Index: head/sys/netinet/tcp_stacks/rack.c =================================================================== --- head/sys/netinet/tcp_stacks/rack.c (revision 344366) +++ head/sys/netinet/tcp_stacks/rack.c (revision 344367) @@ -1,9156 +1,9156 @@ /*- * Copyright (c) 2016-2018 Netflix, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * */ #include __FBSDID("$FreeBSD$"); #include "opt_inet.h" #include "opt_inet6.h" #include "opt_ipsec.h" #include "opt_tcpdebug.h" #include #include #include #ifdef TCP_HHOOK #include #endif #include #include #include #include #include #include /* for proc0 declaration */ #include #include #include #include #ifdef NETFLIX_STATS #include #endif #include #include #include #include #include #include #include #include #define TCPSTATES /* for logging */ #include #include #include #include #include /* required for icmp_var.h */ #include /* for ICMP_BANDLIM */ #include #include #include #include #include #define TCPOUTFLAGS #include #include #include #include #include #include #include #include #ifdef NETFLIX_CWV #include #endif #include #ifdef TCPDEBUG #include #endif /* TCPDEBUG */ #ifdef TCP_OFFLOAD #include #endif #ifdef INET6 #include #endif #include #if defined(IPSEC) || defined(IPSEC_SUPPORT) #include #include #endif /* IPSEC */ #include #include #include #ifdef MAC #include #endif #include "sack_filter.h" #include "tcp_rack.h" #include "rack_bbr_common.h" uma_zone_t rack_zone; uma_zone_t rack_pcb_zone; #ifndef TICKS2SBT #define TICKS2SBT(__t) (tick_sbt * ((sbintime_t)(__t))) #endif struct sysctl_ctx_list rack_sysctl_ctx; struct sysctl_oid *rack_sysctl_root; #define CUM_ACKED 1 #define SACKED 2 /* * The RACK module incorporates a number of * TCP ideas that have been put out into the IETF * over the last few years: * - Matt Mathis's Rate Halving which slowly drops * the congestion window so that the ack clock can * be maintained during a recovery. * - Yuchung Cheng's RACK TCP (for which its named) that * will stop us using the number of dup acks and instead * use time as the gage of when we retransmit. * - Reorder Detection of RFC4737 and the Tail-Loss probe draft * of Dukkipati et.al. * RACK depends on SACK, so if an endpoint arrives that * cannot do SACK the state machine below will shuttle the * connection back to using the "default" TCP stack that is * in FreeBSD. * * To implement RACK the original TCP stack was first decomposed * into a functional state machine with individual states * for each of the possible TCP connection states. The do_segement * functions role in life is to mandate the connection supports SACK * initially and then assure that the RACK state matches the conenction * state before calling the states do_segment function. Each * state is simplified due to the fact that the original do_segment * has been decomposed and we *know* what state we are in (no * switches on the state) and all tests for SACK are gone. This * greatly simplifies what each state does. * * TCP output is also over-written with a new version since it * must maintain the new rack scoreboard. * */ static int32_t rack_precache = 1; static int32_t rack_tlp_thresh = 1; static int32_t rack_reorder_thresh = 2; static int32_t rack_reorder_fade = 60000; /* 0 - never fade, def 60,000 * - 60 seconds */ static int32_t rack_pkt_delay = 1; static int32_t rack_inc_var = 0;/* For TLP */ static int32_t rack_reduce_largest_on_idle = 0; static int32_t rack_min_pace_time = 0; static int32_t rack_min_pace_time_seg_req=6; static int32_t rack_early_recovery = 1; static int32_t rack_early_recovery_max_seg = 6; static int32_t rack_send_a_lot_in_prr = 1; static int32_t rack_min_to = 1; /* Number of ms minimum timeout */ static int32_t rack_tlp_in_recovery = 1; /* Can we do TLP in recovery? */ static int32_t rack_verbose_logging = 0; static int32_t rack_ignore_data_after_close = 1; /* * Currently regular tcp has a rto_min of 30ms * the backoff goes 12 times so that ends up * being a total of 122.850 seconds before a * connection is killed. */ static int32_t rack_tlp_min = 10; static int32_t rack_rto_min = 30; /* 30ms same as main freebsd */ static int32_t rack_rto_max = 30000; /* 30 seconds */ static const int32_t rack_free_cache = 2; static int32_t rack_hptsi_segments = 40; static int32_t rack_rate_sample_method = USE_RTT_LOW; static int32_t rack_pace_every_seg = 1; static int32_t rack_delayed_ack_time = 200; /* 200ms */ static int32_t rack_slot_reduction = 4; static int32_t rack_lower_cwnd_at_tlp = 0; static int32_t rack_use_proportional_reduce = 0; static int32_t rack_proportional_rate = 10; static int32_t rack_tlp_max_resend = 2; static int32_t rack_limited_retran = 0; static int32_t rack_always_send_oldest = 0; static int32_t rack_sack_block_limit = 128; static int32_t rack_use_sack_filter = 1; static int32_t rack_tlp_threshold_use = TLP_USE_TWO_ONE; /* Rack specific counters */ counter_u64_t rack_badfr; counter_u64_t rack_badfr_bytes; counter_u64_t rack_rtm_prr_retran; counter_u64_t rack_rtm_prr_newdata; counter_u64_t rack_timestamp_mismatch; counter_u64_t rack_reorder_seen; counter_u64_t rack_paced_segments; counter_u64_t rack_unpaced_segments; counter_u64_t rack_saw_enobuf; counter_u64_t rack_saw_enetunreach; /* Tail loss probe counters */ counter_u64_t rack_tlp_tot; counter_u64_t rack_tlp_newdata; counter_u64_t rack_tlp_retran; counter_u64_t rack_tlp_retran_bytes; counter_u64_t rack_tlp_retran_fail; counter_u64_t rack_to_tot; counter_u64_t rack_to_arm_rack; counter_u64_t rack_to_arm_tlp; counter_u64_t rack_to_alloc; counter_u64_t rack_to_alloc_hard; counter_u64_t rack_to_alloc_emerg; counter_u64_t rack_sack_proc_all; counter_u64_t rack_sack_proc_short; counter_u64_t rack_sack_proc_restart; counter_u64_t rack_runt_sacks; counter_u64_t rack_used_tlpmethod; counter_u64_t rack_used_tlpmethod2; counter_u64_t rack_enter_tlp_calc; counter_u64_t rack_input_idle_reduces; counter_u64_t rack_tlp_does_nada; /* Temp CPU counters */ counter_u64_t rack_find_high; counter_u64_t rack_progress_drops; counter_u64_t rack_out_size[TCP_MSS_ACCT_SIZE]; counter_u64_t rack_opts_arry[RACK_OPTS_SIZE]; static void rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick, int event, int line); static int rack_process_ack(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, uint32_t tiwin, int32_t tlen, int32_t * ofia, int32_t thflags, int32_t * ret_val); static int rack_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt); static void rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack, struct tcphdr *th, uint16_t nsegs, uint16_t type, int32_t recovery); static struct rack_sendmap *rack_alloc(struct tcp_rack *rack); static struct rack_sendmap * rack_check_recovery_mode(struct tcpcb *tp, uint32_t tsused); static void rack_cong_signal(struct tcpcb *tp, struct tcphdr *th, uint32_t type); static void rack_counter_destroy(void); static int rack_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp); static int32_t rack_ctor(void *mem, int32_t size, void *arg, int32_t how); static void rack_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos); static void rack_dtor(void *mem, int32_t size, void *arg); static void rack_earlier_retran(struct tcpcb *tp, struct rack_sendmap *rsm, uint32_t t, uint32_t cts); static struct rack_sendmap * rack_find_high_nonack(struct tcp_rack *rack, struct rack_sendmap *rsm); static struct rack_sendmap *rack_find_lowest_rsm(struct tcp_rack *rack); static void rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm); static void rack_fini(struct tcpcb *tp, int32_t tcb_is_purged); static int rack_get_sockopt(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack); static int32_t rack_handoff_ok(struct tcpcb *tp); static int32_t rack_init(struct tcpcb *tp); static void rack_init_sysctls(void); static void rack_log_ack(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th); static void rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len, uint32_t seq_out, uint8_t th_flags, int32_t err, uint32_t ts, uint8_t pass, struct rack_sendmap *hintrsm); static void rack_log_sack_passed(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm); static void rack_log_to_event(struct tcp_rack *rack, int32_t to_num); static int32_t rack_output(struct tcpcb *tp); static void rack_hpts_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos, int32_t nxt_pkt, struct timeval *tv); static uint32_t rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack, struct sackblk *sack, struct tcpopt *to, struct rack_sendmap **prsm, uint32_t cts); static void rack_post_recovery(struct tcpcb *tp, struct tcphdr *th); static void rack_remxt_tmr(struct tcpcb *tp); static int rack_set_sockopt(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack); static void rack_set_state(struct tcpcb *tp, struct tcp_rack *rack); static int32_t rack_stopall(struct tcpcb *tp); static void rack_timer_activate(struct tcpcb *tp, uint32_t timer_type, uint32_t delta); static int32_t rack_timer_active(struct tcpcb *tp, uint32_t timer_type); static void rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line); static void rack_timer_stop(struct tcpcb *tp, uint32_t timer_type); static uint32_t rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm, uint32_t ts, int32_t * lenp); static void rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm, uint32_t ts); static int rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type); static int32_t tcp_addrack(module_t mod, int32_t type, void *data); static void rack_challenge_ack(struct mbuf *m, struct tcphdr *th, struct tcpcb *tp, int32_t * ret_val); static int rack_do_close_wait(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt); static int rack_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt); static void rack_do_drop(struct mbuf *m, struct tcpcb *tp); static void rack_do_dropafterack(struct mbuf *m, struct tcpcb *tp, struct tcphdr *th, int32_t thflags, int32_t tlen, int32_t * ret_val); static void rack_do_dropwithreset(struct mbuf *m, struct tcpcb *tp, struct tcphdr *th, int32_t rstreason, int32_t tlen); static int rack_do_established(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt); static int rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t nxt_pkt); static int rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt); static int rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt); static int rack_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt); static int rack_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt); static int rack_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt); static int rack_drop_checks(struct tcpopt *to, struct mbuf *m, struct tcphdr *th, struct tcpcb *tp, int32_t * tlenp, int32_t * thf, int32_t * drop_hdrlen, int32_t * ret_val); static int rack_process_rst(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp); struct rack_sendmap * tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack, uint32_t tsused); static void tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt); static void tcp_rack_partialack(struct tcpcb *tp, struct tcphdr *th); static int rack_ts_check(struct mbuf *m, struct tcphdr *th, struct tcpcb *tp, int32_t tlen, int32_t thflags, int32_t * ret_val); int32_t rack_clear_counter=0; static int sysctl_rack_clear(SYSCTL_HANDLER_ARGS) { uint32_t stat; int32_t error; error = SYSCTL_OUT(req, &rack_clear_counter, sizeof(uint32_t)); if (error || req->newptr == NULL) return error; error = SYSCTL_IN(req, &stat, sizeof(uint32_t)); if (error) return (error); if (stat == 1) { #ifdef INVARIANTS printf("Clearing RACK counters\n"); #endif counter_u64_zero(rack_badfr); counter_u64_zero(rack_badfr_bytes); counter_u64_zero(rack_rtm_prr_retran); counter_u64_zero(rack_rtm_prr_newdata); counter_u64_zero(rack_timestamp_mismatch); counter_u64_zero(rack_reorder_seen); counter_u64_zero(rack_tlp_tot); counter_u64_zero(rack_tlp_newdata); counter_u64_zero(rack_tlp_retran); counter_u64_zero(rack_tlp_retran_bytes); counter_u64_zero(rack_tlp_retran_fail); counter_u64_zero(rack_to_tot); counter_u64_zero(rack_to_arm_rack); counter_u64_zero(rack_to_arm_tlp); counter_u64_zero(rack_paced_segments); counter_u64_zero(rack_unpaced_segments); counter_u64_zero(rack_saw_enobuf); counter_u64_zero(rack_saw_enetunreach); counter_u64_zero(rack_to_alloc_hard); counter_u64_zero(rack_to_alloc_emerg); counter_u64_zero(rack_sack_proc_all); counter_u64_zero(rack_sack_proc_short); counter_u64_zero(rack_sack_proc_restart); counter_u64_zero(rack_to_alloc); counter_u64_zero(rack_find_high); counter_u64_zero(rack_runt_sacks); counter_u64_zero(rack_used_tlpmethod); counter_u64_zero(rack_used_tlpmethod2); counter_u64_zero(rack_enter_tlp_calc); counter_u64_zero(rack_progress_drops); counter_u64_zero(rack_tlp_does_nada); } rack_clear_counter = 0; return (0); } static void rack_init_sysctls() { SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "rate_sample_method", CTLFLAG_RW, &rack_rate_sample_method , USE_RTT_LOW, "What method should we use for rate sampling 0=high, 1=low "); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "data_after_close", CTLFLAG_RW, &rack_ignore_data_after_close, 0, "Do we hold off sending a RST until all pending data is ack'd"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlpmethod", CTLFLAG_RW, &rack_tlp_threshold_use, TLP_USE_TWO_ONE, "What method do we do for TLP time calc 0=no-de-ack-comp, 1=ID, 2=2.1, 3=2.2"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "min_pace_time", CTLFLAG_RW, &rack_min_pace_time, 0, "Should we enforce a minimum pace time of 1ms"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "min_pace_segs", CTLFLAG_RW, &rack_min_pace_time_seg_req, 6, "How many segments have to be in the len to enforce min-pace-time"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "idle_reduce_high", CTLFLAG_RW, &rack_reduce_largest_on_idle, 0, "Should we reduce the largest cwnd seen to IW on idle reduction"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "bb_verbose", CTLFLAG_RW, &rack_verbose_logging, 0, "Should RACK black box logging be verbose"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "sackfiltering", CTLFLAG_RW, &rack_use_sack_filter, 1, "Do we use sack filtering?"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "delayed_ack", CTLFLAG_RW, &rack_delayed_ack_time, 200, "Delayed ack time (200ms)"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlpminto", CTLFLAG_RW, &rack_tlp_min, 10, "TLP minimum timeout per the specification (10ms)"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "precache", CTLFLAG_RW, &rack_precache, 0, "Where should we precache the mcopy (0 is not at all)"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "sblklimit", CTLFLAG_RW, &rack_sack_block_limit, 128, "When do we start paying attention to small sack blocks"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "send_oldest", CTLFLAG_RW, &rack_always_send_oldest, 1, "Should we always send the oldest TLP and RACK-TLP"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "rack_tlp_in_recovery", CTLFLAG_RW, &rack_tlp_in_recovery, 1, "Can we do a TLP during recovery?"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "rack_tlimit", CTLFLAG_RW, &rack_limited_retran, 0, "How many times can a rack timeout drive out sends"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "minrto", CTLFLAG_RW, &rack_rto_min, 0, "Minimum RTO in ms -- set with caution below 1000 due to TLP"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "maxrto", CTLFLAG_RW, &rack_rto_max, 0, "Maxiumum RTO in ms -- should be at least as large as min_rto"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlp_retry", CTLFLAG_RW, &rack_tlp_max_resend, 2, "How many times does TLP retry a single segment or multiple with no ACK"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "recovery_loss_prop", CTLFLAG_RW, &rack_use_proportional_reduce, 0, "Should we proportionaly reduce cwnd based on the number of losses "); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "recovery_prop", CTLFLAG_RW, &rack_proportional_rate, 10, "What percent reduction per loss"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlp_cwnd_flag", CTLFLAG_RW, &rack_lower_cwnd_at_tlp, 0, "When a TLP completes a retran should we enter recovery?"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "hptsi_reduces", CTLFLAG_RW, &rack_slot_reduction, 4, "When setting a slot should we reduce by divisor"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "hptsi_every_seg", CTLFLAG_RW, &rack_pace_every_seg, 1, "Should we pace out every segment hptsi"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "hptsi_seg_max", CTLFLAG_RW, &rack_hptsi_segments, 6, "Should we pace out only a limited size of segments"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "prr_sendalot", CTLFLAG_RW, &rack_send_a_lot_in_prr, 1, "Send a lot in prr"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "minto", CTLFLAG_RW, &rack_min_to, 1, "Minimum rack timeout in milliseconds"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "earlyrecoveryseg", CTLFLAG_RW, &rack_early_recovery_max_seg, 6, "Max segments in early recovery"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "earlyrecovery", CTLFLAG_RW, &rack_early_recovery, 1, "Do we do early recovery with rack"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "reorder_thresh", CTLFLAG_RW, &rack_reorder_thresh, 2, "What factor for rack will be added when seeing reordering (shift right)"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "rtt_tlp_thresh", CTLFLAG_RW, &rack_tlp_thresh, 1, "what divisor for TLP rtt/retran will be added (1=rtt, 2=1/2 rtt etc)"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "reorder_fade", CTLFLAG_RW, &rack_reorder_fade, 0, "Does reorder detection fade, if so how many ms (0 means never)"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "pktdelay", CTLFLAG_RW, &rack_pkt_delay, 1, "Extra RACK time (in ms) besides reordering thresh"); SYSCTL_ADD_S32(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "inc_var", CTLFLAG_RW, &rack_inc_var, 0, "Should rack add to the TLP timer the variance in rtt calculation"); rack_badfr = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "badfr", CTLFLAG_RD, &rack_badfr, "Total number of bad FRs"); rack_badfr_bytes = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "badfr_bytes", CTLFLAG_RD, &rack_badfr_bytes, "Total number of bad FRs"); rack_rtm_prr_retran = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "prrsndret", CTLFLAG_RD, &rack_rtm_prr_retran, "Total number of prr based retransmits"); rack_rtm_prr_newdata = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "prrsndnew", CTLFLAG_RD, &rack_rtm_prr_newdata, "Total number of prr based new transmits"); rack_timestamp_mismatch = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tsnf", CTLFLAG_RD, &rack_timestamp_mismatch, "Total number of timestamps that we could not find the reported ts"); rack_find_high = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "findhigh", CTLFLAG_RD, &rack_find_high, "Total number of FIN causing find-high"); rack_reorder_seen = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "reordering", CTLFLAG_RD, &rack_reorder_seen, "Total number of times we added delay due to reordering"); rack_tlp_tot = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlp_to_total", CTLFLAG_RD, &rack_tlp_tot, "Total number of tail loss probe expirations"); rack_tlp_newdata = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlp_new", CTLFLAG_RD, &rack_tlp_newdata, "Total number of tail loss probe sending new data"); rack_tlp_retran = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlp_retran", CTLFLAG_RD, &rack_tlp_retran, "Total number of tail loss probe sending retransmitted data"); rack_tlp_retran_bytes = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlp_retran_bytes", CTLFLAG_RD, &rack_tlp_retran_bytes, "Total bytes of tail loss probe sending retransmitted data"); rack_tlp_retran_fail = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlp_retran_fail", CTLFLAG_RD, &rack_tlp_retran_fail, "Total number of tail loss probe sending retransmitted data that failed (wait for t3)"); rack_to_tot = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "rack_to_tot", CTLFLAG_RD, &rack_to_tot, "Total number of times the rack to expired?"); rack_to_arm_rack = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "arm_rack", CTLFLAG_RD, &rack_to_arm_rack, "Total number of times the rack timer armed?"); rack_to_arm_tlp = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "arm_tlp", CTLFLAG_RD, &rack_to_arm_tlp, "Total number of times the tlp timer armed?"); rack_paced_segments = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "paced", CTLFLAG_RD, &rack_paced_segments, "Total number of times a segment send caused hptsi"); rack_unpaced_segments = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "unpaced", CTLFLAG_RD, &rack_unpaced_segments, "Total number of times a segment did not cause hptsi"); rack_saw_enobuf = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "saw_enobufs", CTLFLAG_RD, &rack_saw_enobuf, "Total number of times a segment did not cause hptsi"); rack_saw_enetunreach = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "saw_enetunreach", CTLFLAG_RD, &rack_saw_enetunreach, "Total number of times a segment did not cause hptsi"); rack_to_alloc = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "allocs", CTLFLAG_RD, &rack_to_alloc, "Total allocations of tracking structures"); rack_to_alloc_hard = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "allochard", CTLFLAG_RD, &rack_to_alloc_hard, "Total allocations done with sleeping the hard way"); rack_to_alloc_emerg = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "allocemerg", CTLFLAG_RD, &rack_to_alloc_emerg, "Total alocations done from emergency cache"); rack_sack_proc_all = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "sack_long", CTLFLAG_RD, &rack_sack_proc_all, "Total times we had to walk whole list for sack processing"); rack_sack_proc_restart = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "sack_restart", CTLFLAG_RD, &rack_sack_proc_restart, "Total times we had to walk whole list due to a restart"); rack_sack_proc_short = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "sack_short", CTLFLAG_RD, &rack_sack_proc_short, "Total times we took shortcut for sack processing"); rack_enter_tlp_calc = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlp_calc_entered", CTLFLAG_RD, &rack_enter_tlp_calc, "Total times we called calc-tlp"); rack_used_tlpmethod = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "hit_tlp_method", CTLFLAG_RD, &rack_used_tlpmethod, "Total number of runt sacks"); rack_used_tlpmethod2 = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "hit_tlp_method2", CTLFLAG_RD, &rack_used_tlpmethod2, "Total number of runt sacks 2"); rack_runt_sacks = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "runtsacks", CTLFLAG_RD, &rack_runt_sacks, "Total number of runt sacks"); rack_progress_drops = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "prog_drops", CTLFLAG_RD, &rack_progress_drops, "Total number of progress drops"); rack_input_idle_reduces = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "idle_reduce_oninput", CTLFLAG_RD, &rack_input_idle_reduces, "Total number of idle reductions on input"); rack_tlp_does_nada = counter_u64_alloc(M_WAITOK); SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "tlp_nada", CTLFLAG_RD, &rack_tlp_does_nada, "Total number of nada tlp calls"); COUNTER_ARRAY_ALLOC(rack_out_size, TCP_MSS_ACCT_SIZE, M_WAITOK); SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "outsize", CTLFLAG_RD, rack_out_size, TCP_MSS_ACCT_SIZE, "MSS send sizes"); COUNTER_ARRAY_ALLOC(rack_opts_arry, RACK_OPTS_SIZE, M_WAITOK); SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "opts", CTLFLAG_RD, rack_opts_arry, RACK_OPTS_SIZE, "RACK Option Stats"); SYSCTL_ADD_PROC(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root), OID_AUTO, "clear", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE, &rack_clear_counter, 0, sysctl_rack_clear, "IU", "Clear counters"); } static inline int32_t rack_progress_timeout_check(struct tcpcb *tp) { if (tp->t_maxunacktime && tp->t_acktime && TSTMP_GT(ticks, tp->t_acktime)) { if ((ticks - tp->t_acktime) >= tp->t_maxunacktime) { /* * There is an assumption that the caller * will drop the connection so we will * increment the counters here. */ struct tcp_rack *rack; rack = (struct tcp_rack *)tp->t_fb_ptr; counter_u64_add(rack_progress_drops, 1); #ifdef NETFLIX_STATS TCPSTAT_INC(tcps_progdrops); #endif rack_log_progress_event(rack, tp, ticks, PROGRESS_DROP, __LINE__); return (1); } } return (0); } static void rack_log_to_start(struct tcp_rack *rack, uint32_t cts, uint32_t to, int32_t slot, uint8_t which) { if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.flex1 = TICKS_2_MSEC(rack->rc_tp->t_srtt >> TCP_RTT_SHIFT); log.u_bbr.flex2 = to; log.u_bbr.flex3 = rack->r_ctl.rc_hpts_flags; log.u_bbr.flex4 = slot; log.u_bbr.flex5 = rack->rc_inp->inp_hptsslot; log.u_bbr.flex6 = rack->rc_tp->t_rxtcur; log.u_bbr.flex8 = which; log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts; log.u_bbr.ininput = rack->rc_inp->inp_in_input; TCP_LOG_EVENT(rack->rc_tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, BBR_LOG_TIMERSTAR, 0, 0, &log, false); } } static void rack_log_to_event(struct tcp_rack *rack, int32_t to_num) { if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts; log.u_bbr.ininput = rack->rc_inp->inp_in_input; log.u_bbr.flex8 = to_num; log.u_bbr.flex1 = rack->r_ctl.rc_rack_min_rtt; log.u_bbr.flex2 = rack->rc_rack_rtt; TCP_LOG_EVENT(rack->rc_tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, BBR_LOG_RTO, 0, 0, &log, false); } } static void rack_log_rtt_upd(struct tcpcb *tp, struct tcp_rack *rack, int32_t t, uint32_t o_srtt, uint32_t o_var) { if (tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts; log.u_bbr.ininput = rack->rc_inp->inp_in_input; log.u_bbr.flex1 = t; log.u_bbr.flex2 = o_srtt; log.u_bbr.flex3 = o_var; log.u_bbr.flex4 = rack->r_ctl.rack_rs.rs_rtt_lowest; log.u_bbr.flex5 = rack->r_ctl.rack_rs.rs_rtt_highest; log.u_bbr.flex6 = rack->r_ctl.rack_rs.rs_rtt_cnt; log.u_bbr.rttProp = rack->r_ctl.rack_rs.rs_rtt_tot; log.u_bbr.flex8 = rack->r_ctl.rc_rate_sample_method; TCP_LOG_EVENT(tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, BBR_LOG_BBRRTT, 0, 0, &log, false); } } static void rack_log_rtt_sample(struct tcp_rack *rack, uint32_t rtt) { /* * Log the rtt sample we are * applying to the srtt algorithm in * useconds. */ if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; struct timeval tv; /* Convert our ms to a microsecond */ log.u_bbr.flex1 = rtt * 1000; log.u_bbr.timeStamp = tcp_get_usecs(&tv); TCP_LOG_EVENTP(rack->rc_tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, TCP_LOG_RTT, 0, 0, &log, false, &tv); } } static inline void rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick, int event, int line) { if (rack_verbose_logging && (tp->t_logstate != TCP_LOG_STATE_OFF)) { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts; log.u_bbr.ininput = rack->rc_inp->inp_in_input; log.u_bbr.flex1 = line; log.u_bbr.flex2 = tick; log.u_bbr.flex3 = tp->t_maxunacktime; log.u_bbr.flex4 = tp->t_acktime; log.u_bbr.flex8 = event; TCP_LOG_EVENT(tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, BBR_LOG_PROGRESS, 0, 0, &log, false); } } static void rack_log_type_bbrsnd(struct tcp_rack *rack, uint32_t len, uint32_t slot, uint32_t cts) { if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts; log.u_bbr.ininput = rack->rc_inp->inp_in_input; log.u_bbr.flex1 = slot; log.u_bbr.flex7 = (0x0000ffff & rack->r_ctl.rc_hpts_flags); log.u_bbr.flex8 = rack->rc_in_persist; TCP_LOG_EVENT(rack->rc_tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, BBR_LOG_BBRSND, 0, 0, &log, false); } } static void rack_log_doseg_done(struct tcp_rack *rack, uint32_t cts, int32_t nxt_pkt, int32_t did_out, int way_out) { if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; log.u_bbr.flex1 = did_out; log.u_bbr.flex2 = nxt_pkt; log.u_bbr.flex3 = way_out; log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags; log.u_bbr.flex7 = rack->r_wanted_output; log.u_bbr.flex8 = rack->rc_in_persist; TCP_LOG_EVENT(rack->rc_tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, BBR_LOG_DOSEG_DONE, 0, 0, &log, false); } } static void rack_log_type_just_return(struct tcp_rack *rack, uint32_t cts, uint32_t tlen, uint32_t slot, uint8_t hpts_calling) { if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts; log.u_bbr.ininput = rack->rc_inp->inp_in_input; log.u_bbr.flex1 = slot; log.u_bbr.flex2 = rack->r_ctl.rc_hpts_flags; log.u_bbr.flex7 = hpts_calling; log.u_bbr.flex8 = rack->rc_in_persist; TCP_LOG_EVENT(rack->rc_tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, BBR_LOG_JUSTRET, 0, tlen, &log, false); } } static void rack_log_to_cancel(struct tcp_rack *rack, int32_t hpts_removed, int line) { if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts; log.u_bbr.ininput = rack->rc_inp->inp_in_input; log.u_bbr.flex1 = line; log.u_bbr.flex2 = 0; log.u_bbr.flex3 = rack->r_ctl.rc_hpts_flags; log.u_bbr.flex4 = 0; log.u_bbr.flex6 = rack->rc_tp->t_rxtcur; log.u_bbr.flex8 = hpts_removed; TCP_LOG_EVENT(rack->rc_tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, BBR_LOG_TIMERCANC, 0, 0, &log, false); } } static void rack_log_to_processing(struct tcp_rack *rack, uint32_t cts, int32_t ret, int32_t timers) { if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.flex1 = timers; log.u_bbr.flex2 = ret; log.u_bbr.flex3 = rack->r_ctl.rc_timer_exp; log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags; log.u_bbr.flex5 = cts; TCP_LOG_EVENT(rack->rc_tp, NULL, &rack->rc_inp->inp_socket->so_rcv, &rack->rc_inp->inp_socket->so_snd, BBR_LOG_TO_PROCESS, 0, 0, &log, false); } } static void rack_counter_destroy() { counter_u64_free(rack_badfr); counter_u64_free(rack_badfr_bytes); counter_u64_free(rack_rtm_prr_retran); counter_u64_free(rack_rtm_prr_newdata); counter_u64_free(rack_timestamp_mismatch); counter_u64_free(rack_reorder_seen); counter_u64_free(rack_tlp_tot); counter_u64_free(rack_tlp_newdata); counter_u64_free(rack_tlp_retran); counter_u64_free(rack_tlp_retran_bytes); counter_u64_free(rack_tlp_retran_fail); counter_u64_free(rack_to_tot); counter_u64_free(rack_to_arm_rack); counter_u64_free(rack_to_arm_tlp); counter_u64_free(rack_paced_segments); counter_u64_free(rack_unpaced_segments); counter_u64_free(rack_saw_enobuf); counter_u64_free(rack_saw_enetunreach); counter_u64_free(rack_to_alloc_hard); counter_u64_free(rack_to_alloc_emerg); counter_u64_free(rack_sack_proc_all); counter_u64_free(rack_sack_proc_short); counter_u64_free(rack_sack_proc_restart); counter_u64_free(rack_to_alloc); counter_u64_free(rack_find_high); counter_u64_free(rack_runt_sacks); counter_u64_free(rack_enter_tlp_calc); counter_u64_free(rack_used_tlpmethod); counter_u64_free(rack_used_tlpmethod2); counter_u64_free(rack_progress_drops); counter_u64_free(rack_input_idle_reduces); counter_u64_free(rack_tlp_does_nada); COUNTER_ARRAY_FREE(rack_out_size, TCP_MSS_ACCT_SIZE); COUNTER_ARRAY_FREE(rack_opts_arry, RACK_OPTS_SIZE); } static struct rack_sendmap * rack_alloc(struct tcp_rack *rack) { struct rack_sendmap *rsm; counter_u64_add(rack_to_alloc, 1); rack->r_ctl.rc_num_maps_alloced++; rsm = uma_zalloc(rack_zone, M_NOWAIT); if (rsm) { return (rsm); } if (rack->rc_free_cnt) { counter_u64_add(rack_to_alloc_emerg, 1); rsm = TAILQ_FIRST(&rack->r_ctl.rc_free); TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_next); rack->rc_free_cnt--; return (rsm); } return (NULL); } static void rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm) { rack->r_ctl.rc_num_maps_alloced--; if (rack->r_ctl.rc_tlpsend == rsm) rack->r_ctl.rc_tlpsend = NULL; if (rack->r_ctl.rc_next == rsm) rack->r_ctl.rc_next = NULL; if (rack->r_ctl.rc_sacklast == rsm) rack->r_ctl.rc_sacklast = NULL; if (rack->rc_free_cnt < rack_free_cache) { memset(rsm, 0, sizeof(struct rack_sendmap)); TAILQ_INSERT_TAIL(&rack->r_ctl.rc_free, rsm, r_next); rack->rc_free_cnt++; return; } uma_zfree(rack_zone, rsm); } /* * CC wrapper hook functions */ static void rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack, struct tcphdr *th, uint16_t nsegs, uint16_t type, int32_t recovery) { #ifdef NETFLIX_STATS int32_t gput; #endif #ifdef NETFLIX_CWV u_long old_cwnd = tp->snd_cwnd; #endif INP_WLOCK_ASSERT(tp->t_inpcb); tp->ccv->nsegs = nsegs; tp->ccv->bytes_this_ack = BYTES_THIS_ACK(tp, th); if ((recovery) && (rack->r_ctl.rc_early_recovery_segs)) { uint32_t max; max = rack->r_ctl.rc_early_recovery_segs * tp->t_maxseg; if (tp->ccv->bytes_this_ack > max) { tp->ccv->bytes_this_ack = max; } } if (tp->snd_cwnd <= tp->snd_wnd) tp->ccv->flags |= CCF_CWND_LIMITED; else tp->ccv->flags &= ~CCF_CWND_LIMITED; if (type == CC_ACK) { #ifdef NETFLIX_STATS stats_voi_update_abs_s32(tp->t_stats, VOI_TCP_CALCFRWINDIFF, ((int32_t) tp->snd_cwnd) - tp->snd_wnd); if ((tp->t_flags & TF_GPUTINPROG) && SEQ_GEQ(th->th_ack, tp->gput_ack)) { gput = (((int64_t) (th->th_ack - tp->gput_seq)) << 3) / max(1, tcp_ts_getticks() - tp->gput_ts); stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_GPUT, gput); /* * XXXLAS: This is a temporary hack, and should be * chained off VOI_TCP_GPUT when stats(9) grows an * API to deal with chained VOIs. */ if (tp->t_stats_gput_prev > 0) stats_voi_update_abs_s32(tp->t_stats, VOI_TCP_GPUT_ND, ((gput - tp->t_stats_gput_prev) * 100) / tp->t_stats_gput_prev); tp->t_flags &= ~TF_GPUTINPROG; tp->t_stats_gput_prev = gput; #ifdef NETFLIX_CWV if (tp->t_maxpeakrate) { /* * We update t_peakrate_thr. This gives us roughly * one update per round trip time. */ tcp_update_peakrate_thr(tp); } #endif } #endif if (tp->snd_cwnd > tp->snd_ssthresh) { tp->t_bytes_acked += min(tp->ccv->bytes_this_ack, nsegs * V_tcp_abc_l_var * tp->t_maxseg); if (tp->t_bytes_acked >= tp->snd_cwnd) { tp->t_bytes_acked -= tp->snd_cwnd; tp->ccv->flags |= CCF_ABC_SENTAWND; } } else { tp->ccv->flags &= ~CCF_ABC_SENTAWND; tp->t_bytes_acked = 0; } } if (CC_ALGO(tp)->ack_received != NULL) { /* XXXLAS: Find a way to live without this */ tp->ccv->curack = th->th_ack; CC_ALGO(tp)->ack_received(tp->ccv, type); } #ifdef NETFLIX_STATS stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_LCWIN, tp->snd_cwnd); #endif if (rack->r_ctl.rc_rack_largest_cwnd < tp->snd_cwnd) { rack->r_ctl.rc_rack_largest_cwnd = tp->snd_cwnd; } #ifdef NETFLIX_CWV if (tp->cwv_enabled) { /* * Per RFC 7661: The behaviour in the non-validated phase is * specified as: o A sender determines whether to increase * the cwnd based upon whether it is cwnd-limited (see * Section 4.5.3): * A sender that is cwnd-limited MAY use * the standard TCP method to increase cwnd (i.e., the * standard method permits a TCP sender that fully utilises * the cwnd to increase the cwnd each time it receives an * ACK). * A sender that is not cwnd-limited MUST NOT * increase the cwnd when ACK packets are received in this * phase (i.e., needs to avoid growing the cwnd when it has * not recently sent using the current size of cwnd). */ if ((tp->snd_cwnd > old_cwnd) && (tp->cwv_cwnd_valid == 0) && (!(tp->ccv->flags & CCF_CWND_LIMITED))) { tp->snd_cwnd = old_cwnd; } /* Try to update pipeAck and NCWV state */ if (TCPS_HAVEESTABLISHED(tp->t_state) && !IN_RECOVERY(tp->t_flags)) { uint32_t data = sbavail(&(tp->t_inpcb->inp_socket->so_snd)); tcp_newcwv_update_pipeack(tp, data); } } /* we enforce max peak rate if it is set. */ if (tp->t_peakrate_thr && tp->snd_cwnd > tp->t_peakrate_thr) { tp->snd_cwnd = tp->t_peakrate_thr; } #endif } static void tcp_rack_partialack(struct tcpcb *tp, struct tcphdr *th) { struct tcp_rack *rack; rack = (struct tcp_rack *)tp->t_fb_ptr; INP_WLOCK_ASSERT(tp->t_inpcb); if (rack->r_ctl.rc_prr_sndcnt > 0) rack->r_wanted_output++; } static void rack_post_recovery(struct tcpcb *tp, struct tcphdr *th) { struct tcp_rack *rack; INP_WLOCK_ASSERT(tp->t_inpcb); rack = (struct tcp_rack *)tp->t_fb_ptr; if (CC_ALGO(tp)->post_recovery != NULL) { tp->ccv->curack = th->th_ack; CC_ALGO(tp)->post_recovery(tp->ccv); } /* * Here we can in theory adjust cwnd to be based on the number of * losses in the window (rack->r_ctl.rc_loss_count). This is done * based on the rack_use_proportional flag. */ if (rack->r_ctl.rc_prop_reduce && rack->r_ctl.rc_prop_rate) { int32_t reduce; reduce = (rack->r_ctl.rc_loss_count * rack->r_ctl.rc_prop_rate); if (reduce > 50) { reduce = 50; } tp->snd_cwnd -= ((reduce * tp->snd_cwnd) / 100); } else { if (tp->snd_cwnd > tp->snd_ssthresh) { /* Drop us down to the ssthresh (1/2 cwnd at loss) */ tp->snd_cwnd = tp->snd_ssthresh; } } if (rack->r_ctl.rc_prr_sndcnt > 0) { /* Suck the next prr cnt back into cwnd */ tp->snd_cwnd += rack->r_ctl.rc_prr_sndcnt; rack->r_ctl.rc_prr_sndcnt = 0; } EXIT_RECOVERY(tp->t_flags); #ifdef NETFLIX_CWV if (tp->cwv_enabled) { if ((tp->cwv_cwnd_valid == 0) && (tp->snd_cwv.in_recovery)) tcp_newcwv_end_recovery(tp); } #endif } static void rack_cong_signal(struct tcpcb *tp, struct tcphdr *th, uint32_t type) { struct tcp_rack *rack; INP_WLOCK_ASSERT(tp->t_inpcb); rack = (struct tcp_rack *)tp->t_fb_ptr; switch (type) { case CC_NDUPACK: /* rack->r_ctl.rc_ssthresh_set = 1;*/ if (!IN_FASTRECOVERY(tp->t_flags)) { rack->r_ctl.rc_tlp_rtx_out = 0; rack->r_ctl.rc_prr_delivered = 0; rack->r_ctl.rc_prr_out = 0; rack->r_ctl.rc_loss_count = 0; rack->r_ctl.rc_prr_sndcnt = tp->t_maxseg; rack->r_ctl.rc_prr_recovery_fs = tp->snd_max - tp->snd_una; tp->snd_recover = tp->snd_max; if (tp->t_flags & TF_ECN_PERMIT) tp->t_flags |= TF_ECN_SND_CWR; } break; case CC_ECN: if (!IN_CONGRECOVERY(tp->t_flags)) { TCPSTAT_INC(tcps_ecn_rcwnd); tp->snd_recover = tp->snd_max; if (tp->t_flags & TF_ECN_PERMIT) tp->t_flags |= TF_ECN_SND_CWR; } break; case CC_RTO: tp->t_dupacks = 0; tp->t_bytes_acked = 0; EXIT_RECOVERY(tp->t_flags); tp->snd_ssthresh = max(2, min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg) * tp->t_maxseg; tp->snd_cwnd = tp->t_maxseg; break; case CC_RTO_ERR: TCPSTAT_INC(tcps_sndrexmitbad); /* RTO was unnecessary, so reset everything. */ tp->snd_cwnd = tp->snd_cwnd_prev; tp->snd_ssthresh = tp->snd_ssthresh_prev; tp->snd_recover = tp->snd_recover_prev; if (tp->t_flags & TF_WASFRECOVERY) ENTER_FASTRECOVERY(tp->t_flags); if (tp->t_flags & TF_WASCRECOVERY) ENTER_CONGRECOVERY(tp->t_flags); tp->snd_nxt = tp->snd_max; tp->t_badrxtwin = 0; break; } if (CC_ALGO(tp)->cong_signal != NULL) { if (th != NULL) tp->ccv->curack = th->th_ack; CC_ALGO(tp)->cong_signal(tp->ccv, type); } #ifdef NETFLIX_CWV if (tp->cwv_enabled) { if (tp->snd_cwv.in_recovery == 0 && IN_RECOVERY(tp->t_flags)) { tcp_newcwv_enter_recovery(tp); } if (type == CC_RTO) { tcp_newcwv_reset(tp); } } #endif } static inline void rack_cc_after_idle(struct tcpcb *tp, int reduce_largest) { uint32_t i_cwnd; INP_WLOCK_ASSERT(tp->t_inpcb); #ifdef NETFLIX_STATS TCPSTAT_INC(tcps_idle_restarts); if (tp->t_state == TCPS_ESTABLISHED) TCPSTAT_INC(tcps_idle_estrestarts); #endif if (CC_ALGO(tp)->after_idle != NULL) CC_ALGO(tp)->after_idle(tp->ccv); if (tp->snd_cwnd == 1) i_cwnd = tp->t_maxseg; /* SYN(-ACK) lost */ else i_cwnd = tcp_compute_initwnd(tcp_maxseg(tp)); if (reduce_largest) { /* * Do we reduce the largest cwnd to make * rack play nice on restart hptsi wise? */ if (((struct tcp_rack *)tp->t_fb_ptr)->r_ctl.rc_rack_largest_cwnd > i_cwnd) ((struct tcp_rack *)tp->t_fb_ptr)->r_ctl.rc_rack_largest_cwnd = i_cwnd; } /* * Being idle is no differnt than the initial window. If the cc * clamps it down below the initial window raise it to the initial * window. */ if (tp->snd_cwnd < i_cwnd) { tp->snd_cwnd = i_cwnd; } } /* * Indicate whether this ack should be delayed. We can delay the ack if * following conditions are met: * - There is no delayed ack timer in progress. * - Our last ack wasn't a 0-sized window. We never want to delay * the ack that opens up a 0-sized window. * - LRO wasn't used for this segment. We make sure by checking that the * segment size is not larger than the MSS. * - Delayed acks are enabled or this is a half-synchronized T/TCP * connection. */ #define DELAY_ACK(tp, tlen) \ (((tp->t_flags & TF_RXWIN0SENT) == 0) && \ ((tp->t_flags & TF_DELACK) == 0) && \ (tlen <= tp->t_maxseg) && \ (tp->t_delayed_ack || (tp->t_flags & TF_NEEDSYN))) static inline void rack_calc_rwin(struct socket *so, struct tcpcb *tp) { int32_t win; /* * Calculate amount of space in receive window, and then do TCP * input processing. Receive window is amount of space in rcv queue, * but not less than advertised window. */ win = sbspace(&so->so_rcv); if (win < 0) win = 0; tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt)); } static void rack_do_drop(struct mbuf *m, struct tcpcb *tp) { /* * Drop space held by incoming segment and return. */ if (tp != NULL) INP_WUNLOCK(tp->t_inpcb); if (m) m_freem(m); } static void rack_do_dropwithreset(struct mbuf *m, struct tcpcb *tp, struct tcphdr *th, int32_t rstreason, int32_t tlen) { if (tp != NULL) { tcp_dropwithreset(m, th, tp, tlen, rstreason); INP_WUNLOCK(tp->t_inpcb); } else tcp_dropwithreset(m, th, NULL, tlen, rstreason); } /* * The value in ret_val informs the caller * if we dropped the tcb (and lock) or not. * 1 = we dropped it, 0 = the TCB is still locked * and valid. */ static void rack_do_dropafterack(struct mbuf *m, struct tcpcb *tp, struct tcphdr *th, int32_t thflags, int32_t tlen, int32_t * ret_val) { /* * Generate an ACK dropping incoming segment if it occupies sequence * space, where the ACK reflects our state. * * We can now skip the test for the RST flag since all paths to this * code happen after packets containing RST have been dropped. * * In the SYN-RECEIVED state, don't send an ACK unless the segment * we received passes the SYN-RECEIVED ACK test. If it fails send a * RST. This breaks the loop in the "LAND" DoS attack, and also * prevents an ACK storm between two listening ports that have been * sent forged SYN segments, each with the source address of the * other. */ struct tcp_rack *rack; if (tp->t_state == TCPS_SYN_RECEIVED && (thflags & TH_ACK) && (SEQ_GT(tp->snd_una, th->th_ack) || SEQ_GT(th->th_ack, tp->snd_max))) { *ret_val = 1; rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return; } else *ret_val = 0; rack = (struct tcp_rack *)tp->t_fb_ptr; rack->r_wanted_output++; tp->t_flags |= TF_ACKNOW; if (m) m_freem(m); } static int rack_process_rst(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp) { /* * RFC5961 Section 3.2 * * - RST drops connection only if SEG.SEQ == RCV.NXT. - If RST is in * window, we send challenge ACK. * * Note: to take into account delayed ACKs, we should test against * last_ack_sent instead of rcv_nxt. Note 2: we handle special case * of closed window, not covered by the RFC. */ int dropped = 0; if ((SEQ_GEQ(th->th_seq, (tp->last_ack_sent - 1)) && SEQ_LT(th->th_seq, tp->last_ack_sent + tp->rcv_wnd)) || (tp->rcv_wnd == 0 && tp->last_ack_sent == th->th_seq)) { INP_INFO_RLOCK_ASSERT(&V_tcbinfo); KASSERT(tp->t_state != TCPS_SYN_SENT, ("%s: TH_RST for TCPS_SYN_SENT th %p tp %p", __func__, th, tp)); if (V_tcp_insecure_rst || (tp->last_ack_sent == th->th_seq) || (tp->rcv_nxt == th->th_seq) || ((tp->last_ack_sent - 1) == th->th_seq)) { TCPSTAT_INC(tcps_drops); /* Drop the connection. */ switch (tp->t_state) { case TCPS_SYN_RECEIVED: so->so_error = ECONNREFUSED; goto close; case TCPS_ESTABLISHED: case TCPS_FIN_WAIT_1: case TCPS_FIN_WAIT_2: case TCPS_CLOSE_WAIT: case TCPS_CLOSING: case TCPS_LAST_ACK: so->so_error = ECONNRESET; close: tcp_state_change(tp, TCPS_CLOSED); /* FALLTHROUGH */ default: tp = tcp_close(tp); } dropped = 1; rack_do_drop(m, tp); } else { TCPSTAT_INC(tcps_badrst); /* Send challenge ACK. */ tcp_respond(tp, mtod(m, void *), th, m, tp->rcv_nxt, tp->snd_nxt, TH_ACK); tp->last_ack_sent = tp->rcv_nxt; } } else { m_freem(m); } return (dropped); } /* * The value in ret_val informs the caller * if we dropped the tcb (and lock) or not. * 1 = we dropped it, 0 = the TCB is still locked * and valid. */ static void rack_challenge_ack(struct mbuf *m, struct tcphdr *th, struct tcpcb *tp, int32_t * ret_val) { INP_INFO_RLOCK_ASSERT(&V_tcbinfo); TCPSTAT_INC(tcps_badsyn); if (V_tcp_insecure_syn && SEQ_GEQ(th->th_seq, tp->last_ack_sent) && SEQ_LT(th->th_seq, tp->last_ack_sent + tp->rcv_wnd)) { tp = tcp_drop(tp, ECONNRESET); *ret_val = 1; rack_do_drop(m, tp); } else { /* Send challenge ACK. */ tcp_respond(tp, mtod(m, void *), th, m, tp->rcv_nxt, tp->snd_nxt, TH_ACK); tp->last_ack_sent = tp->rcv_nxt; m = NULL; *ret_val = 0; rack_do_drop(m, NULL); } } /* * rack_ts_check returns 1 for you should not proceed. It places * in ret_val what should be returned 1/0 by the caller. The 1 indicates * that the TCB is unlocked and probably dropped. The 0 indicates the * TCB is still valid and locked. */ static int rack_ts_check(struct mbuf *m, struct tcphdr *th, struct tcpcb *tp, int32_t tlen, int32_t thflags, int32_t * ret_val) { /* Check to see if ts_recent is over 24 days old. */ if (tcp_ts_getticks() - tp->ts_recent_age > TCP_PAWS_IDLE) { /* * Invalidate ts_recent. If this segment updates ts_recent, * the age will be reset later and ts_recent will get a * valid value. If it does not, setting ts_recent to zero * will at least satisfy the requirement that zero be placed * in the timestamp echo reply when ts_recent isn't valid. * The age isn't reset until we get a valid ts_recent * because we don't want out-of-order segments to be dropped * when ts_recent is old. */ tp->ts_recent = 0; } else { TCPSTAT_INC(tcps_rcvduppack); TCPSTAT_ADD(tcps_rcvdupbyte, tlen); TCPSTAT_INC(tcps_pawsdrop); *ret_val = 0; if (tlen) { rack_do_dropafterack(m, tp, th, thflags, tlen, ret_val); } else { rack_do_drop(m, NULL); } return (1); } return (0); } /* * rack_drop_checks returns 1 for you should not proceed. It places * in ret_val what should be returned 1/0 by the caller. The 1 indicates * that the TCB is unlocked and probably dropped. The 0 indicates the * TCB is still valid and locked. */ static int rack_drop_checks(struct tcpopt *to, struct mbuf *m, struct tcphdr *th, struct tcpcb *tp, int32_t * tlenp, int32_t * thf, int32_t * drop_hdrlen, int32_t * ret_val) { int32_t todrop; int32_t thflags; int32_t tlen; thflags = *thf; tlen = *tlenp; todrop = tp->rcv_nxt - th->th_seq; if (todrop > 0) { if (thflags & TH_SYN) { thflags &= ~TH_SYN; th->th_seq++; if (th->th_urp > 1) th->th_urp--; else thflags &= ~TH_URG; todrop--; } /* * Following if statement from Stevens, vol. 2, p. 960. */ if (todrop > tlen || (todrop == tlen && (thflags & TH_FIN) == 0)) { /* * Any valid FIN must be to the left of the window. * At this point the FIN must be a duplicate or out * of sequence; drop it. */ thflags &= ~TH_FIN; /* * Send an ACK to resynchronize and drop any data. * But keep on processing for RST or ACK. */ tp->t_flags |= TF_ACKNOW; todrop = tlen; TCPSTAT_INC(tcps_rcvduppack); TCPSTAT_ADD(tcps_rcvdupbyte, todrop); } else { TCPSTAT_INC(tcps_rcvpartduppack); TCPSTAT_ADD(tcps_rcvpartdupbyte, todrop); } *drop_hdrlen += todrop; /* drop from the top afterwards */ th->th_seq += todrop; tlen -= todrop; if (th->th_urp > todrop) th->th_urp -= todrop; else { thflags &= ~TH_URG; th->th_urp = 0; } } /* * If segment ends after window, drop trailing data (and PUSH and * FIN); if nothing left, just ACK. */ todrop = (th->th_seq + tlen) - (tp->rcv_nxt + tp->rcv_wnd); if (todrop > 0) { TCPSTAT_INC(tcps_rcvpackafterwin); if (todrop >= tlen) { TCPSTAT_ADD(tcps_rcvbyteafterwin, tlen); /* * If window is closed can only take segments at * window edge, and have to drop data and PUSH from * incoming segments. Continue processing, but * remember to ack. Otherwise, drop segment and * ack. */ if (tp->rcv_wnd == 0 && th->th_seq == tp->rcv_nxt) { tp->t_flags |= TF_ACKNOW; TCPSTAT_INC(tcps_rcvwinprobe); } else { rack_do_dropafterack(m, tp, th, thflags, tlen, ret_val); return (1); } } else TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop); m_adj(m, -todrop); tlen -= todrop; thflags &= ~(TH_PUSH | TH_FIN); } *thf = thflags; *tlenp = tlen; return (0); } static struct rack_sendmap * rack_find_lowest_rsm(struct tcp_rack *rack) { struct rack_sendmap *rsm; /* * Walk the time-order transmitted list looking for an rsm that is * not acked. This will be the one that was sent the longest time * ago that is still outstanding. */ TAILQ_FOREACH(rsm, &rack->r_ctl.rc_tmap, r_tnext) { if (rsm->r_flags & RACK_ACKED) { continue; } goto finish; } finish: return (rsm); } static struct rack_sendmap * rack_find_high_nonack(struct tcp_rack *rack, struct rack_sendmap *rsm) { struct rack_sendmap *prsm; /* * Walk the sequence order list backward until we hit and arrive at * the highest seq not acked. In theory when this is called it * should be the last segment (which it was not). */ counter_u64_add(rack_find_high, 1); prsm = rsm; TAILQ_FOREACH_REVERSE_FROM(prsm, &rack->r_ctl.rc_map, rack_head, r_next) { if (prsm->r_flags & (RACK_ACKED | RACK_HAS_FIN)) { continue; } return (prsm); } return (NULL); } static uint32_t rack_calc_thresh_rack(struct tcp_rack *rack, uint32_t srtt, uint32_t cts) { int32_t lro; uint32_t thresh; /* * lro is the flag we use to determine if we have seen reordering. * If it gets set we have seen reordering. The reorder logic either * works in one of two ways: * * If reorder-fade is configured, then we track the last time we saw * re-ordering occur. If we reach the point where enough time as * passed we no longer consider reordering has occuring. * * Or if reorder-face is 0, then once we see reordering we consider * the connection to alway be subject to reordering and just set lro * to 1. * * In the end if lro is non-zero we add the extra time for * reordering in. */ if (srtt == 0) srtt = 1; if (rack->r_ctl.rc_reorder_ts) { if (rack->r_ctl.rc_reorder_fade) { if (SEQ_GEQ(cts, rack->r_ctl.rc_reorder_ts)) { lro = cts - rack->r_ctl.rc_reorder_ts; if (lro == 0) { /* * No time as passed since the last * reorder, mark it as reordering. */ lro = 1; } } else { /* Negative time? */ lro = 0; } if (lro > rack->r_ctl.rc_reorder_fade) { /* Turn off reordering seen too */ rack->r_ctl.rc_reorder_ts = 0; lro = 0; } } else { /* Reodering does not fade */ lro = 1; } } else { lro = 0; } thresh = srtt + rack->r_ctl.rc_pkt_delay; if (lro) { /* It must be set, if not you get 1/4 rtt */ if (rack->r_ctl.rc_reorder_shift) thresh += (srtt >> rack->r_ctl.rc_reorder_shift); else thresh += (srtt >> 2); } else { thresh += 1; } /* We don't let the rack timeout be above a RTO */ if (thresh > TICKS_2_MSEC(rack->rc_tp->t_rxtcur)) { thresh = TICKS_2_MSEC(rack->rc_tp->t_rxtcur); } /* And we don't want it above the RTO max either */ if (thresh > rack_rto_max) { thresh = rack_rto_max; } return (thresh); } static uint32_t rack_calc_thresh_tlp(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm, uint32_t srtt) { struct rack_sendmap *prsm; uint32_t thresh, len; int maxseg; if (srtt == 0) srtt = 1; if (rack->r_ctl.rc_tlp_threshold) thresh = srtt + (srtt / rack->r_ctl.rc_tlp_threshold); else thresh = (srtt * 2); /* Get the previous sent packet, if any */ maxseg = tcp_maxseg(tp); counter_u64_add(rack_enter_tlp_calc, 1); len = rsm->r_end - rsm->r_start; if (rack->rack_tlp_threshold_use == TLP_USE_ID) { /* Exactly like the ID */ if (((tp->snd_max - tp->snd_una) - rack->r_ctl.rc_sacked + rack->r_ctl.rc_holes_rxt) <= maxseg) { uint32_t alt_thresh; /* * Compensate for delayed-ack with the d-ack time. */ counter_u64_add(rack_used_tlpmethod, 1); alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time; if (alt_thresh > thresh) thresh = alt_thresh; } } else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_ONE) { /* 2.1 behavior */ prsm = TAILQ_PREV(rsm, rack_head, r_tnext); if (prsm && (len <= maxseg)) { /* * Two packets outstanding, thresh should be (2*srtt) + * possible inter-packet delay (if any). */ uint32_t inter_gap = 0; int idx, nidx; counter_u64_add(rack_used_tlpmethod, 1); idx = rsm->r_rtr_cnt - 1; nidx = prsm->r_rtr_cnt - 1; if (TSTMP_GEQ(rsm->r_tim_lastsent[nidx], prsm->r_tim_lastsent[idx])) { /* Yes it was sent later (or at the same time) */ inter_gap = rsm->r_tim_lastsent[idx] - prsm->r_tim_lastsent[nidx]; } thresh += inter_gap; } else if (len <= maxseg) { /* * Possibly compensate for delayed-ack. */ uint32_t alt_thresh; counter_u64_add(rack_used_tlpmethod2, 1); alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time; if (alt_thresh > thresh) thresh = alt_thresh; } } else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_TWO) { /* 2.2 behavior */ if (len <= maxseg) { uint32_t alt_thresh; /* * Compensate for delayed-ack with the d-ack time. */ counter_u64_add(rack_used_tlpmethod, 1); alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time; if (alt_thresh > thresh) thresh = alt_thresh; } } /* Not above an RTO */ if (thresh > TICKS_2_MSEC(tp->t_rxtcur)) { thresh = TICKS_2_MSEC(tp->t_rxtcur); } /* Not above a RTO max */ if (thresh > rack_rto_max) { thresh = rack_rto_max; } /* Apply user supplied min TLP */ if (thresh < rack_tlp_min) { thresh = rack_tlp_min; } return (thresh); } static struct rack_sendmap * rack_check_recovery_mode(struct tcpcb *tp, uint32_t tsused) { /* * Check to see that we don't need to fall into recovery. We will * need to do so if our oldest transmit is past the time we should * have had an ack. */ struct tcp_rack *rack; struct rack_sendmap *rsm; int32_t idx; uint32_t srtt_cur, srtt, thresh; rack = (struct tcp_rack *)tp->t_fb_ptr; if (TAILQ_EMPTY(&rack->r_ctl.rc_map)) { return (NULL); } srtt_cur = tp->t_srtt >> TCP_RTT_SHIFT; srtt = TICKS_2_MSEC(srtt_cur); if (rack->rc_rack_rtt && (srtt > rack->rc_rack_rtt)) srtt = rack->rc_rack_rtt; rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap); if (rsm == NULL) return (NULL); if (rsm->r_flags & RACK_ACKED) { rsm = rack_find_lowest_rsm(rack); if (rsm == NULL) return (NULL); } idx = rsm->r_rtr_cnt - 1; thresh = rack_calc_thresh_rack(rack, srtt, tsused); if (tsused < rsm->r_tim_lastsent[idx]) { return (NULL); } if ((tsused - rsm->r_tim_lastsent[idx]) < thresh) { return (NULL); } /* Ok if we reach here we are over-due */ rack->r_ctl.rc_rsm_start = rsm->r_start; rack->r_ctl.rc_cwnd_at = tp->snd_cwnd; rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh; rack_cong_signal(tp, NULL, CC_NDUPACK); return (rsm); } static uint32_t rack_get_persists_timer_val(struct tcpcb *tp, struct tcp_rack *rack) { int32_t t; int32_t tt; uint32_t ret_val; t = TICKS_2_MSEC((tp->t_srtt >> TCP_RTT_SHIFT) + ((tp->t_rttvar * 4) >> TCP_RTT_SHIFT)); TCPT_RANGESET(tt, t * tcp_backoff[tp->t_rxtshift], tcp_persmin, tcp_persmax); if (tp->t_rxtshift < TCP_MAXRXTSHIFT) tp->t_rxtshift++; rack->r_ctl.rc_hpts_flags |= PACE_TMR_PERSIT; ret_val = (uint32_t)tt; return (ret_val); } static uint32_t rack_timer_start(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts) { /* * Start the FR timer, we do this based on getting the first one in * the rc_tmap. Note that if its NULL we must stop the timer. in all * events we need to stop the running timer (if its running) before * starting the new one. */ uint32_t thresh, exp, to, srtt, time_since_sent; uint32_t srtt_cur; int32_t idx; int32_t is_tlp_timer = 0; struct rack_sendmap *rsm; if (rack->t_timers_stopped) { /* All timers have been stopped none are to run */ return (0); } if (rack->rc_in_persist) { /* We can't start any timer in persists */ return (rack_get_persists_timer_val(tp, rack)); } if (tp->t_state < TCPS_ESTABLISHED) goto activate_rxt; rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap); if (rsm == NULL) { /* Nothing on the send map */ activate_rxt: if (SEQ_LT(tp->snd_una, tp->snd_max) || sbavail(&(tp->t_inpcb->inp_socket->so_snd))) { rack->r_ctl.rc_hpts_flags |= PACE_TMR_RXT; to = TICKS_2_MSEC(tp->t_rxtcur); if (to == 0) to = 1; return (to); } return (0); } if (rsm->r_flags & RACK_ACKED) { rsm = rack_find_lowest_rsm(rack); if (rsm == NULL) { /* No lowest? */ goto activate_rxt; } } /* Convert from ms to usecs */ if (rsm->r_flags & RACK_SACK_PASSED) { if ((tp->t_flags & TF_SENTFIN) && ((tp->snd_max - tp->snd_una) == 1) && (rsm->r_flags & RACK_HAS_FIN)) { /* * We don't start a rack timer if all we have is a * FIN outstanding. */ goto activate_rxt; } if (tp->t_srtt) { srtt_cur = (tp->t_srtt >> TCP_RTT_SHIFT); srtt = TICKS_2_MSEC(srtt_cur); } else srtt = RACK_INITIAL_RTO; thresh = rack_calc_thresh_rack(rack, srtt, cts); idx = rsm->r_rtr_cnt - 1; exp = rsm->r_tim_lastsent[idx] + thresh; if (SEQ_GEQ(exp, cts)) { to = exp - cts; if (to < rack->r_ctl.rc_min_to) { to = rack->r_ctl.rc_min_to; } } else { to = rack->r_ctl.rc_min_to; } } else { /* Ok we need to do a TLP not RACK */ if ((rack->rc_tlp_in_progress != 0) || (rack->r_ctl.rc_tlp_rtx_out != 0)) { /* * The previous send was a TLP or a tlp_rtx is in * process. */ goto activate_rxt; } rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext); if (rsm == NULL) { /* We found no rsm to TLP with. */ goto activate_rxt; } if (rsm->r_flags & RACK_HAS_FIN) { /* If its a FIN we dont do TLP */ rsm = NULL; goto activate_rxt; } idx = rsm->r_rtr_cnt - 1; if (TSTMP_GT(cts, rsm->r_tim_lastsent[idx])) time_since_sent = cts - rsm->r_tim_lastsent[idx]; else time_since_sent = 0; is_tlp_timer = 1; if (tp->t_srtt) { srtt_cur = (tp->t_srtt >> TCP_RTT_SHIFT); srtt = TICKS_2_MSEC(srtt_cur); } else srtt = RACK_INITIAL_RTO; thresh = rack_calc_thresh_tlp(tp, rack, rsm, srtt); if (thresh > time_since_sent) to = thresh - time_since_sent; else to = rack->r_ctl.rc_min_to; if (to > TCPTV_REXMTMAX) { /* * If the TLP time works out to larger than the max * RTO lets not do TLP.. just RTO. */ goto activate_rxt; } if (rsm->r_start != rack->r_ctl.rc_last_tlp_seq) { /* * The tail is no longer the last one I did a probe * on */ rack->r_ctl.rc_tlp_seg_send_cnt = 0; rack->r_ctl.rc_last_tlp_seq = rsm->r_start; } } if (is_tlp_timer == 0) { rack->r_ctl.rc_hpts_flags |= PACE_TMR_RACK; } else { if ((rack->r_ctl.rc_tlp_send_cnt > rack_tlp_max_resend) || (rack->r_ctl.rc_tlp_seg_send_cnt > rack_tlp_max_resend)) { /* * We have exceeded how many times we can retran the * current TLP timer, switch to the RTO timer. */ goto activate_rxt; } else { rack->r_ctl.rc_hpts_flags |= PACE_TMR_TLP; } } if (to == 0) to = 1; return (to); } static void rack_enter_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts) { if (rack->rc_in_persist == 0) { if (((tp->t_flags & TF_SENTFIN) == 0) && (tp->snd_max - tp->snd_una) >= sbavail(&rack->rc_inp->inp_socket->so_snd)) /* Must need to send more data to enter persist */ return; rack->r_ctl.rc_went_idle_time = cts; rack_timer_cancel(tp, rack, cts, __LINE__); tp->t_rxtshift = 0; rack->rc_in_persist = 1; } } static void rack_exit_persist(struct tcpcb *tp, struct tcp_rack *rack) { if (rack->rc_inp->inp_in_hpts) { tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT); rack->r_ctl.rc_hpts_flags = 0; } rack->rc_in_persist = 0; rack->r_ctl.rc_went_idle_time = 0; tp->t_flags &= ~TF_FORCEDATA; tp->t_rxtshift = 0; } static void rack_start_hpts_timer(struct tcp_rack *rack, struct tcpcb *tp, uint32_t cts, int32_t line, int32_t slot, uint32_t tot_len_this_send, int32_t frm_out_sbavail) { struct inpcb *inp; uint32_t delayed_ack = 0; uint32_t hpts_timeout; uint8_t stopped; uint32_t left = 0; inp = tp->t_inpcb; if (inp->inp_in_hpts) { /* A previous call is already set up */ return; } if (tp->t_state == TCPS_CLOSED) { return; } stopped = rack->rc_tmr_stopped; if (stopped && TSTMP_GT(rack->r_ctl.rc_timer_exp, cts)) { left = rack->r_ctl.rc_timer_exp - cts; } rack->r_ctl.rc_timer_exp = 0; if (rack->rc_inp->inp_in_hpts == 0) { rack->r_ctl.rc_hpts_flags = 0; } if (slot) { /* We are hptsi too */ rack->r_ctl.rc_hpts_flags |= PACE_PKT_OUTPUT; } else if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) { /* * We are still left on the hpts when the to goes * it will be for output. */ if (TSTMP_GT(cts, rack->r_ctl.rc_last_output_to)) slot = cts - rack->r_ctl.rc_last_output_to; else slot = 1; } if ((tp->snd_wnd == 0) && TCPS_HAVEESTABLISHED(tp->t_state)) { /* No send window.. we must enter persist */ rack_enter_persist(tp, rack, cts); } else if ((frm_out_sbavail && (frm_out_sbavail > (tp->snd_max - tp->snd_una)) && (tp->snd_wnd < tp->t_maxseg)) && TCPS_HAVEESTABLISHED(tp->t_state)) { /* * If we have no window or we can't send a segment (and have * data to send.. we cheat here and frm_out_sbavail is * passed in with the sbavail(sb) only from bbr_output) and * we are established, then we must enter persits (if not * already in persits). */ rack_enter_persist(tp, rack, cts); } hpts_timeout = rack_timer_start(tp, rack, cts); if (tp->t_flags & TF_DELACK) { delayed_ack = TICKS_2_MSEC(tcp_delacktime); rack->r_ctl.rc_hpts_flags |= PACE_TMR_DELACK; } if (delayed_ack && ((hpts_timeout == 0) || (delayed_ack < hpts_timeout))) hpts_timeout = delayed_ack; else rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK; /* * If no timers are going to run and we will fall off the hptsi * wheel, we resort to a keep-alive timer if its configured. */ if ((hpts_timeout == 0) && (slot == 0)) { if ((tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) && (tp->t_state <= TCPS_CLOSING)) { /* * Ok we have no timer (persists, rack, tlp, rxt or * del-ack), we don't have segments being paced. So * all that is left is the keepalive timer. */ if (TCPS_HAVEESTABLISHED(tp->t_state)) { /* Get the established keep-alive time */ hpts_timeout = TP_KEEPIDLE(tp); } else { /* Get the initial setup keep-alive time */ hpts_timeout = TP_KEEPINIT(tp); } rack->r_ctl.rc_hpts_flags |= PACE_TMR_KEEP; } } if (left && (stopped & (PACE_TMR_KEEP | PACE_TMR_DELACK)) == (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK)) { /* * RACK, TLP, persists and RXT timers all are restartable * based on actions input .. i.e we received a packet (ack * or sack) and that changes things (rw, or snd_una etc). * Thus we can restart them with a new value. For * keep-alive, delayed_ack we keep track of what was left * and restart the timer with a smaller value. */ if (left < hpts_timeout) hpts_timeout = left; } if (hpts_timeout) { /* * Hack alert for now we can't time-out over 2,147,483 * seconds (a bit more than 596 hours), which is probably ok * :). */ if (hpts_timeout > 0x7ffffffe) hpts_timeout = 0x7ffffffe; rack->r_ctl.rc_timer_exp = cts + hpts_timeout; } if (slot) { rack->r_ctl.rc_last_output_to = cts + slot; if ((hpts_timeout == 0) || (hpts_timeout > slot)) { if (rack->rc_inp->inp_in_hpts == 0) tcp_hpts_insert(tp->t_inpcb, HPTS_MS_TO_SLOTS(slot)); rack_log_to_start(rack, cts, hpts_timeout, slot, 1); } else { /* * Arrange for the hpts to kick back in after the * t-o if the t-o does not cause a send. */ if (rack->rc_inp->inp_in_hpts == 0) tcp_hpts_insert(tp->t_inpcb, HPTS_MS_TO_SLOTS(hpts_timeout)); rack_log_to_start(rack, cts, hpts_timeout, slot, 0); } } else if (hpts_timeout) { if (rack->rc_inp->inp_in_hpts == 0) tcp_hpts_insert(tp->t_inpcb, HPTS_MS_TO_SLOTS(hpts_timeout)); rack_log_to_start(rack, cts, hpts_timeout, slot, 0); } else { /* No timer starting */ #ifdef INVARIANTS if (SEQ_GT(tp->snd_max, tp->snd_una)) { panic("tp:%p rack:%p tlts:%d cts:%u slot:%u pto:%u -- no timer started?", tp, rack, tot_len_this_send, cts, slot, hpts_timeout); } #endif } rack->rc_tmr_stopped = 0; if (slot) rack_log_type_bbrsnd(rack, tot_len_this_send, slot, cts); } /* * RACK Timer, here we simply do logging and house keeping. * the normal rack_output() function will call the * appropriate thing to check if we need to do a RACK retransmit. * We return 1, saying don't proceed with rack_output only * when all timers have been stopped (destroyed PCB?). */ static int rack_timeout_rack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts) { /* * This timer simply provides an internal trigger to send out data. * The check_recovery_mode call will see if there are needed * retransmissions, if so we will enter fast-recovery. The output * call may or may not do the same thing depending on sysctl * settings. */ struct rack_sendmap *rsm; int32_t recovery; if (tp->t_timers->tt_flags & TT_STOPPED) { return (1); } if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) { /* Its not time yet */ return (0); } rack_log_to_event(rack, RACK_TO_FRM_RACK); recovery = IN_RECOVERY(tp->t_flags); counter_u64_add(rack_to_tot, 1); if (rack->r_state && (rack->r_state != tp->t_state)) rack_set_state(tp, rack); rsm = rack_check_recovery_mode(tp, cts); if (rsm) { uint32_t rtt; rtt = rack->rc_rack_rtt; if (rtt == 0) rtt = 1; if ((recovery == 0) && (rack->r_ctl.rc_prr_sndcnt < tp->t_maxseg)) { /* * The rack-timeout that enter's us into recovery * will force out one MSS and set us up so that we * can do one more send in 2*rtt (transitioning the * rack timeout into a rack-tlp). */ rack->r_ctl.rc_prr_sndcnt = tp->t_maxseg; } else if ((rack->r_ctl.rc_prr_sndcnt < tp->t_maxseg) && ((rsm->r_end - rsm->r_start) > rack->r_ctl.rc_prr_sndcnt)) { /* * When a rack timer goes, we have to send at * least one segment. They will be paced a min of 1ms * apart via the next rack timer (or further * if the rack timer dictates it). */ rack->r_ctl.rc_prr_sndcnt = tp->t_maxseg; } } else { /* This is a case that should happen rarely if ever */ counter_u64_add(rack_tlp_does_nada, 1); #ifdef TCP_BLACKBOX tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true); #endif rack->r_ctl.rc_resend = TAILQ_FIRST(&rack->r_ctl.rc_tmap); } rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RACK; return (0); } /* * TLP Timer, here we simply setup what segment we want to * have the TLP expire on, the normal rack_output() will then * send it out. * * We return 1, saying don't proceed with rack_output only * when all timers have been stopped (destroyed PCB?). */ static int rack_timeout_tlp(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts) { /* * Tail Loss Probe. */ struct rack_sendmap *rsm = NULL; struct socket *so; uint32_t amm, old_prr_snd = 0; uint32_t out, avail; if (tp->t_timers->tt_flags & TT_STOPPED) { return (1); } if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) { /* Its not time yet */ return (0); } if (rack_progress_timeout_check(tp)) { tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT); return (1); } /* * A TLP timer has expired. We have been idle for 2 rtts. So we now * need to figure out how to force a full MSS segment out. */ rack_log_to_event(rack, RACK_TO_FRM_TLP); counter_u64_add(rack_tlp_tot, 1); if (rack->r_state && (rack->r_state != tp->t_state)) rack_set_state(tp, rack); so = tp->t_inpcb->inp_socket; avail = sbavail(&so->so_snd); out = tp->snd_max - tp->snd_una; rack->rc_timer_up = 1; /* * If we are in recovery we can jazz out a segment if new data is * present simply by setting rc_prr_sndcnt to a segment. */ if ((avail > out) && ((rack_always_send_oldest == 0) || (TAILQ_EMPTY(&rack->r_ctl.rc_tmap)))) { /* New data is available */ amm = avail - out; if (amm > tp->t_maxseg) { amm = tp->t_maxseg; } else if ((amm < tp->t_maxseg) && ((tp->t_flags & TF_NODELAY) == 0)) { /* not enough to fill a MTU and no-delay is off */ goto need_retran; } if (IN_RECOVERY(tp->t_flags)) { /* Unlikely */ old_prr_snd = rack->r_ctl.rc_prr_sndcnt; if (out + amm <= tp->snd_wnd) rack->r_ctl.rc_prr_sndcnt = amm; else goto need_retran; } else { /* Set the send-new override */ if (out + amm <= tp->snd_wnd) rack->r_ctl.rc_tlp_new_data = amm; else goto need_retran; } rack->r_ctl.rc_tlp_seg_send_cnt = 0; rack->r_ctl.rc_last_tlp_seq = tp->snd_max; rack->r_ctl.rc_tlpsend = NULL; counter_u64_add(rack_tlp_newdata, 1); goto send; } need_retran: /* * Ok we need to arrange the last un-acked segment to be re-sent, or * optionally the first un-acked segment. */ if (rack_always_send_oldest) rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap); else { rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_map, rack_sendmap, r_next); if (rsm && (rsm->r_flags & (RACK_ACKED | RACK_HAS_FIN))) { rsm = rack_find_high_nonack(rack, rsm); } } if (rsm == NULL) { counter_u64_add(rack_tlp_does_nada, 1); #ifdef TCP_BLACKBOX tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true); #endif goto out; } if ((rsm->r_end - rsm->r_start) > tp->t_maxseg) { /* * We need to split this the last segment in two. */ int32_t idx; struct rack_sendmap *nrsm; nrsm = rack_alloc(rack); if (nrsm == NULL) { /* * No memory to split, we will just exit and punt * off to the RXT timer. */ counter_u64_add(rack_tlp_does_nada, 1); goto out; } nrsm->r_start = (rsm->r_end - tp->t_maxseg); nrsm->r_end = rsm->r_end; nrsm->r_rtr_cnt = rsm->r_rtr_cnt; nrsm->r_flags = rsm->r_flags; nrsm->r_sndcnt = rsm->r_sndcnt; nrsm->r_rtr_bytes = 0; rsm->r_end = nrsm->r_start; for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) { nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx]; } TAILQ_INSERT_AFTER(&rack->r_ctl.rc_map, rsm, nrsm, r_next); if (rsm->r_in_tmap) { TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext); nrsm->r_in_tmap = 1; } rsm->r_flags &= (~RACK_HAS_FIN); rsm = nrsm; } rack->r_ctl.rc_tlpsend = rsm; rack->r_ctl.rc_tlp_rtx_out = 1; if (rsm->r_start == rack->r_ctl.rc_last_tlp_seq) { rack->r_ctl.rc_tlp_seg_send_cnt++; tp->t_rxtshift++; } else { rack->r_ctl.rc_last_tlp_seq = rsm->r_start; rack->r_ctl.rc_tlp_seg_send_cnt = 1; } send: rack->r_ctl.rc_tlp_send_cnt++; if (rack->r_ctl.rc_tlp_send_cnt > rack_tlp_max_resend) { /* * Can't [re]/transmit a segment we have not heard from the * peer in max times. We need the retransmit timer to take * over. */ restore: rack->r_ctl.rc_tlpsend = NULL; if (rsm) rsm->r_flags &= ~RACK_TLP; rack->r_ctl.rc_prr_sndcnt = old_prr_snd; counter_u64_add(rack_tlp_retran_fail, 1); goto out; } else if (rsm) { rsm->r_flags |= RACK_TLP; } if (rsm && (rsm->r_start == rack->r_ctl.rc_last_tlp_seq) && (rack->r_ctl.rc_tlp_seg_send_cnt > rack_tlp_max_resend)) { /* * We don't want to send a single segment more than the max * either. */ goto restore; } rack->r_timer_override = 1; rack->r_tlp_running = 1; rack->rc_tlp_in_progress = 1; rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP; return (0); out: rack->rc_timer_up = 0; rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP; return (0); } /* * Delayed ack Timer, here we simply need to setup the * ACK_NOW flag and remove the DELACK flag. From there * the output routine will send the ack out. * * We only return 1, saying don't proceed, if all timers * are stopped (destroyed PCB?). */ static int rack_timeout_delack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts) { if (tp->t_timers->tt_flags & TT_STOPPED) { return (1); } rack_log_to_event(rack, RACK_TO_FRM_DELACK); tp->t_flags &= ~TF_DELACK; tp->t_flags |= TF_ACKNOW; TCPSTAT_INC(tcps_delack); rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK; return (0); } /* * Persists timer, here we simply need to setup the * FORCE-DATA flag the output routine will send * the one byte send. * * We only return 1, saying don't proceed, if all timers * are stopped (destroyed PCB?). */ static int rack_timeout_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts) { struct inpcb *inp; int32_t retval = 0; inp = tp->t_inpcb; if (tp->t_timers->tt_flags & TT_STOPPED) { return (1); } if (rack->rc_in_persist == 0) return (0); if (rack_progress_timeout_check(tp)) { tcp_set_inp_to_drop(inp, ETIMEDOUT); return (1); } KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); /* * Persistence timer into zero window. Force a byte to be output, if * possible. */ TCPSTAT_INC(tcps_persisttimeo); /* * Hack: if the peer is dead/unreachable, we do not time out if the * window is closed. After a full backoff, drop the connection if * the idle time (no responses to probes) reaches the maximum * backoff that we would use if retransmitting. */ if (tp->t_rxtshift == TCP_MAXRXTSHIFT && (ticks - tp->t_rcvtime >= tcp_maxpersistidle || ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) { TCPSTAT_INC(tcps_persistdrop); retval = 1; tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT); goto out; } if ((sbavail(&rack->rc_inp->inp_socket->so_snd) == 0) && tp->snd_una == tp->snd_max) rack_exit_persist(tp, rack); rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_PERSIT; /* * If the user has closed the socket then drop a persisting * connection after a much reduced timeout. */ if (tp->t_state > TCPS_CLOSE_WAIT && (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) { retval = 1; TCPSTAT_INC(tcps_persistdrop); tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT); goto out; } tp->t_flags |= TF_FORCEDATA; out: rack_log_to_event(rack, RACK_TO_FRM_PERSIST); return (retval); } /* * If a keepalive goes off, we had no other timers * happening. We always return 1 here since this * routine either drops the connection or sends * out a segment with respond. */ static int rack_timeout_keepalive(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts) { struct tcptemp *t_template; struct inpcb *inp; if (tp->t_timers->tt_flags & TT_STOPPED) { return (1); } rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_KEEP; inp = tp->t_inpcb; rack_log_to_event(rack, RACK_TO_FRM_KEEP); /* * Keep-alive timer went off; send something or drop connection if * idle for too long. */ TCPSTAT_INC(tcps_keeptimeo); if (tp->t_state < TCPS_ESTABLISHED) goto dropit; if ((tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) && tp->t_state <= TCPS_CLOSING) { if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp)) goto dropit; /* * Send a packet designed to force a response if the peer is * up and reachable: either an ACK if the connection is * still alive, or an RST if the peer has closed the * connection due to timeout or reboot. Using sequence * number tp->snd_una-1 causes the transmitted zero-length * segment to lie outside the receive window; by the * protocol spec, this requires the correspondent TCP to * respond. */ TCPSTAT_INC(tcps_keepprobe); t_template = tcpip_maketemplate(inp); if (t_template) { tcp_respond(tp, t_template->tt_ipgen, &t_template->tt_t, (struct mbuf *)NULL, tp->rcv_nxt, tp->snd_una - 1, 0); free(t_template, M_TEMP); } } rack_start_hpts_timer(rack, tp, cts, __LINE__, 0, 0, 0); return (1); dropit: TCPSTAT_INC(tcps_keepdrops); tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT); return (1); } /* * Retransmit helper function, clear up all the ack * flags and take care of important book keeping. */ static void rack_remxt_tmr(struct tcpcb *tp) { /* * The retransmit timer went off, all sack'd blocks must be * un-acked. */ struct rack_sendmap *rsm, *trsm = NULL; struct tcp_rack *rack; int32_t cnt = 0; rack = (struct tcp_rack *)tp->t_fb_ptr; rack_timer_cancel(tp, rack, tcp_ts_getticks(), __LINE__); rack_log_to_event(rack, RACK_TO_FRM_TMR); if (rack->r_state && (rack->r_state != tp->t_state)) rack_set_state(tp, rack); /* * Ideally we would like to be able to * mark SACK-PASS on anything not acked here. * However, if we do that we would burst out * all that data 1ms apart. This would be unwise, * so for now we will just let the normal rxt timer * and tlp timer take care of it. */ TAILQ_FOREACH(rsm, &rack->r_ctl.rc_map, r_next) { if (rsm->r_flags & RACK_ACKED) { cnt++; rsm->r_sndcnt = 0; if (rsm->r_in_tmap == 0) { /* We must re-add it back to the tlist */ if (trsm == NULL) { TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext); } else { TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, trsm, rsm, r_tnext); } rsm->r_in_tmap = 1; trsm = rsm; } } rsm->r_flags &= ~(RACK_ACKED | RACK_SACK_PASSED | RACK_WAS_SACKPASS); } /* Clear the count (we just un-acked them) */ rack->r_ctl.rc_sacked = 0; /* Clear the tlp rtx mark */ rack->r_ctl.rc_tlp_rtx_out = 0; rack->r_ctl.rc_tlp_seg_send_cnt = 0; rack->r_ctl.rc_resend = TAILQ_FIRST(&rack->r_ctl.rc_map); /* Setup so we send one segment */ if (rack->r_ctl.rc_prr_sndcnt < tp->t_maxseg) rack->r_ctl.rc_prr_sndcnt = tp->t_maxseg; rack->r_timer_override = 1; } /* * Re-transmit timeout! If we drop the PCB we will return 1, otherwise * we will setup to retransmit the lowest seq number outstanding. */ static int rack_timeout_rxt(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts) { int32_t rexmt; struct inpcb *inp; int32_t retval = 0; inp = tp->t_inpcb; if (tp->t_timers->tt_flags & TT_STOPPED) { return (1); } if (rack_progress_timeout_check(tp)) { tcp_set_inp_to_drop(inp, ETIMEDOUT); return (1); } rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RXT; if (TCPS_HAVEESTABLISHED(tp->t_state) && (tp->snd_una == tp->snd_max)) { /* Nothing outstanding .. nothing to do */ return (0); } /* * Retransmission timer went off. Message has not been acked within * retransmit interval. Back off to a longer retransmit interval * and retransmit one segment. */ if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { tp->t_rxtshift = TCP_MAXRXTSHIFT; TCPSTAT_INC(tcps_timeoutdrop); retval = 1; tcp_set_inp_to_drop(rack->rc_inp, (tp->t_softerror ? (uint16_t) tp->t_softerror : ETIMEDOUT)); goto out; } rack_remxt_tmr(tp); if (tp->t_state == TCPS_SYN_SENT) { /* * If the SYN was retransmitted, indicate CWND to be limited * to 1 segment in cc_conn_init(). */ tp->snd_cwnd = 1; } else if (tp->t_rxtshift == 1) { /* * first retransmit; record ssthresh and cwnd so they can be * recovered if this turns out to be a "bad" retransmit. A * retransmit is considered "bad" if an ACK for this segment * is received within RTT/2 interval; the assumption here is * that the ACK was already in flight. See "On Estimating * End-to-End Network Path Properties" by Allman and Paxson * for more details. */ tp->snd_cwnd_prev = tp->snd_cwnd; tp->snd_ssthresh_prev = tp->snd_ssthresh; tp->snd_recover_prev = tp->snd_recover; if (IN_FASTRECOVERY(tp->t_flags)) tp->t_flags |= TF_WASFRECOVERY; else tp->t_flags &= ~TF_WASFRECOVERY; if (IN_CONGRECOVERY(tp->t_flags)) tp->t_flags |= TF_WASCRECOVERY; else tp->t_flags &= ~TF_WASCRECOVERY; tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1)); tp->t_flags |= TF_PREVVALID; } else tp->t_flags &= ~TF_PREVVALID; TCPSTAT_INC(tcps_rexmttimeo); if ((tp->t_state == TCPS_SYN_SENT) || (tp->t_state == TCPS_SYN_RECEIVED)) - rexmt = MSEC_2_TICKS(RACK_INITIAL_RTO * tcp_syn_backoff[tp->t_rxtshift]); + rexmt = MSEC_2_TICKS(RACK_INITIAL_RTO * tcp_backoff[tp->t_rxtshift]); else rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift]; TCPT_RANGESET(tp->t_rxtcur, rexmt, max(MSEC_2_TICKS(rack_rto_min), rexmt), MSEC_2_TICKS(rack_rto_max)); /* * We enter the path for PLMTUD if connection is established or, if * connection is FIN_WAIT_1 status, reason for the last is that if * amount of data we send is very small, we could send it in couple * of packets and process straight to FIN. In that case we won't * catch ESTABLISHED state. */ if (V_tcp_pmtud_blackhole_detect && (((tp->t_state == TCPS_ESTABLISHED)) || (tp->t_state == TCPS_FIN_WAIT_1))) { #ifdef INET6 int32_t isipv6; #endif /* * Idea here is that at each stage of mtu probe (usually, * 1448 -> 1188 -> 524) should be given 2 chances to recover * before further clamping down. 'tp->t_rxtshift % 2 == 0' * should take care of that. */ if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) == (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) && (tp->t_rxtshift >= 2 && tp->t_rxtshift < 6 && tp->t_rxtshift % 2 == 0)) { /* * Enter Path MTU Black-hole Detection mechanism: - * Disable Path MTU Discovery (IP "DF" bit). - * Reduce MTU to lower value than what we negotiated * with peer. */ if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) == 0) { /* Record that we may have found a black hole. */ tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE; /* Keep track of previous MSS. */ tp->t_pmtud_saved_maxseg = tp->t_maxseg; } /* * Reduce the MSS to blackhole value or to the * default in an attempt to retransmit. */ #ifdef INET6 isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? 1 : 0; if (isipv6 && tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss) { /* Use the sysctl tuneable blackhole MSS. */ tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss; TCPSTAT_INC(tcps_pmtud_blackhole_activated); } else if (isipv6) { /* Use the default MSS. */ tp->t_maxseg = V_tcp_v6mssdflt; /* * Disable Path MTU Discovery when we switch * to minmss. */ tp->t_flags2 &= ~TF2_PLPMTU_PMTUD; TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss); } #endif #if defined(INET6) && defined(INET) else #endif #ifdef INET if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss) { /* Use the sysctl tuneable blackhole MSS. */ tp->t_maxseg = V_tcp_pmtud_blackhole_mss; TCPSTAT_INC(tcps_pmtud_blackhole_activated); } else { /* Use the default MSS. */ tp->t_maxseg = V_tcp_mssdflt; /* * Disable Path MTU Discovery when we switch * to minmss. */ tp->t_flags2 &= ~TF2_PLPMTU_PMTUD; TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss); } #endif } else { /* * If further retransmissions are still unsuccessful * with a lowered MTU, maybe this isn't a blackhole * and we restore the previous MSS and blackhole * detection flags. The limit '6' is determined by * giving each probe stage (1448, 1188, 524) 2 * chances to recover. */ if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) && (tp->t_rxtshift >= 6)) { tp->t_flags2 |= TF2_PLPMTU_PMTUD; tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE; tp->t_maxseg = tp->t_pmtud_saved_maxseg; TCPSTAT_INC(tcps_pmtud_blackhole_failed); } } } /* * Disable RFC1323 and SACK if we haven't got any response to our * third SYN to work-around some broken terminal servers (most of * which have hopefully been retired) that have bad VJ header * compression code which trashes TCP segments containing * unknown-to-them TCP options. */ if (tcp_rexmit_drop_options && (tp->t_state == TCPS_SYN_SENT) && (tp->t_rxtshift == 3)) tp->t_flags &= ~(TF_REQ_SCALE | TF_REQ_TSTMP | TF_SACK_PERMIT); /* * If we backed off this far, our srtt estimate is probably bogus. * Clobber it so we'll take the next rtt measurement as our srtt; * move the current srtt into rttvar to keep the current retransmit * times until then. */ if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { #ifdef INET6 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) in6_losing(tp->t_inpcb); else #endif in_losing(tp->t_inpcb); tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); tp->t_srtt = 0; } if (rack_use_sack_filter) sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una); tp->snd_recover = tp->snd_max; tp->t_flags |= TF_ACKNOW; tp->t_rtttime = 0; rack_cong_signal(tp, NULL, CC_RTO); out: return (retval); } static int rack_process_timers(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, uint8_t hpts_calling) { int32_t ret = 0; int32_t timers = (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK); if (timers == 0) { return (0); } if (tp->t_state == TCPS_LISTEN) { /* no timers on listen sockets */ if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) return (0); return (1); } if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) { uint32_t left; if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) { ret = -1; rack_log_to_processing(rack, cts, ret, 0); return (0); } if (hpts_calling == 0) { ret = -2; rack_log_to_processing(rack, cts, ret, 0); return (0); } /* * Ok our timer went off early and we are not paced false * alarm, go back to sleep. */ ret = -3; left = rack->r_ctl.rc_timer_exp - cts; tcp_hpts_insert(tp->t_inpcb, HPTS_MS_TO_SLOTS(left)); rack_log_to_processing(rack, cts, ret, left); rack->rc_last_pto_set = 0; return (1); } rack->rc_tmr_stopped = 0; rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_MASK; if (timers & PACE_TMR_DELACK) { ret = rack_timeout_delack(tp, rack, cts); } else if (timers & PACE_TMR_RACK) { ret = rack_timeout_rack(tp, rack, cts); } else if (timers & PACE_TMR_TLP) { ret = rack_timeout_tlp(tp, rack, cts); } else if (timers & PACE_TMR_RXT) { ret = rack_timeout_rxt(tp, rack, cts); } else if (timers & PACE_TMR_PERSIT) { ret = rack_timeout_persist(tp, rack, cts); } else if (timers & PACE_TMR_KEEP) { ret = rack_timeout_keepalive(tp, rack, cts); } rack_log_to_processing(rack, cts, ret, timers); return (ret); } static void rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line) { uint8_t hpts_removed = 0; if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) && TSTMP_GEQ(cts, rack->r_ctl.rc_last_output_to)) { tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT); hpts_removed = 1; } if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) { rack->rc_tmr_stopped = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK; if (rack->rc_inp->inp_in_hpts && ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0)) { /* * Canceling timer's when we have no output being * paced. We also must remove ourselves from the * hpts. */ tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT); hpts_removed = 1; } rack_log_to_cancel(rack, hpts_removed, line); rack->r_ctl.rc_hpts_flags &= ~(PACE_TMR_MASK); } } static void rack_timer_stop(struct tcpcb *tp, uint32_t timer_type) { return; } static int rack_stopall(struct tcpcb *tp) { struct tcp_rack *rack; rack = (struct tcp_rack *)tp->t_fb_ptr; rack->t_timers_stopped = 1; return (0); } static void rack_timer_activate(struct tcpcb *tp, uint32_t timer_type, uint32_t delta) { return; } static int rack_timer_active(struct tcpcb *tp, uint32_t timer_type) { return (0); } static void rack_stop_all_timers(struct tcpcb *tp) { struct tcp_rack *rack; /* * Assure no timers are running. */ if (tcp_timer_active(tp, TT_PERSIST)) { /* We enter in persists, set the flag appropriately */ rack = (struct tcp_rack *)tp->t_fb_ptr; rack->rc_in_persist = 1; } tcp_timer_suspend(tp, TT_PERSIST); tcp_timer_suspend(tp, TT_REXMT); tcp_timer_suspend(tp, TT_KEEP); tcp_timer_suspend(tp, TT_DELACK); } static void rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm, uint32_t ts) { int32_t idx; rsm->r_rtr_cnt++; rsm->r_sndcnt++; if (rsm->r_rtr_cnt > RACK_NUM_OF_RETRANS) { rsm->r_rtr_cnt = RACK_NUM_OF_RETRANS; rsm->r_flags |= RACK_OVERMAX; } if ((rsm->r_rtr_cnt > 1) && (rack->r_tlp_running == 0)) { rack->r_ctl.rc_holes_rxt += (rsm->r_end - rsm->r_start); rsm->r_rtr_bytes += (rsm->r_end - rsm->r_start); } idx = rsm->r_rtr_cnt - 1; rsm->r_tim_lastsent[idx] = ts; if (rsm->r_flags & RACK_ACKED) { /* Problably MTU discovery messing with us */ rsm->r_flags &= ~RACK_ACKED; rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start); } if (rsm->r_in_tmap) { TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext); } TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext); rsm->r_in_tmap = 1; if (rsm->r_flags & RACK_SACK_PASSED) { /* We have retransmitted due to the SACK pass */ rsm->r_flags &= ~RACK_SACK_PASSED; rsm->r_flags |= RACK_WAS_SACKPASS; } /* Update memory for next rtr */ rack->r_ctl.rc_next = TAILQ_NEXT(rsm, r_next); } static uint32_t rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm, uint32_t ts, int32_t * lenp) { /* * We (re-)transmitted starting at rsm->r_start for some length * (possibly less than r_end. */ struct rack_sendmap *nrsm; uint32_t c_end; int32_t len; int32_t idx; len = *lenp; c_end = rsm->r_start + len; if (SEQ_GEQ(c_end, rsm->r_end)) { /* * We retransmitted the whole piece or more than the whole * slopping into the next rsm. */ rack_update_rsm(tp, rack, rsm, ts); if (c_end == rsm->r_end) { *lenp = 0; return (0); } else { int32_t act_len; /* Hangs over the end return whats left */ act_len = rsm->r_end - rsm->r_start; *lenp = (len - act_len); return (rsm->r_end); } /* We don't get out of this block. */ } /* * Here we retransmitted less than the whole thing which means we * have to split this into what was transmitted and what was not. */ nrsm = rack_alloc(rack); if (nrsm == NULL) { /* * We can't get memory, so lets not proceed. */ *lenp = 0; return (0); } /* * So here we are going to take the original rsm and make it what we * retransmitted. nrsm will be the tail portion we did not * retransmit. For example say the chunk was 1, 11 (10 bytes). And * we retransmitted 5 bytes i.e. 1, 5. The original piece shrinks to * 1, 6 and the new piece will be 6, 11. */ nrsm->r_start = c_end; nrsm->r_end = rsm->r_end; nrsm->r_rtr_cnt = rsm->r_rtr_cnt; nrsm->r_flags = rsm->r_flags; nrsm->r_sndcnt = rsm->r_sndcnt; nrsm->r_rtr_bytes = 0; rsm->r_end = c_end; for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) { nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx]; } TAILQ_INSERT_AFTER(&rack->r_ctl.rc_map, rsm, nrsm, r_next); if (rsm->r_in_tmap) { TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext); nrsm->r_in_tmap = 1; } rsm->r_flags &= (~RACK_HAS_FIN); rack_update_rsm(tp, rack, rsm, ts); *lenp = 0; return (0); } static void rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len, uint32_t seq_out, uint8_t th_flags, int32_t err, uint32_t ts, uint8_t pass, struct rack_sendmap *hintrsm) { struct tcp_rack *rack; struct rack_sendmap *rsm, *nrsm; register uint32_t snd_max, snd_una; int32_t idx; /* * Add to the RACK log of packets in flight or retransmitted. If * there is a TS option we will use the TS echoed, if not we will * grab a TS. * * Retransmissions will increment the count and move the ts to its * proper place. Note that if options do not include TS's then we * won't be able to effectively use the ACK for an RTT on a retran. * * Notes about r_start and r_end. Lets consider a send starting at * sequence 1 for 10 bytes. In such an example the r_start would be * 1 (starting sequence) but the r_end would be r_start+len i.e. 11. * This means that r_end is actually the first sequence for the next * slot (11). * */ /* * If err is set what do we do XXXrrs? should we not add the thing? * -- i.e. return if err != 0 or should we pretend we sent it? -- * i.e. proceed with add ** do this for now. */ INP_WLOCK_ASSERT(tp->t_inpcb); if (err) /* * We don't log errors -- we could but snd_max does not * advance in this case either. */ return; if (th_flags & TH_RST) { /* * We don't log resets and we return immediately from * sending */ return; } rack = (struct tcp_rack *)tp->t_fb_ptr; snd_una = tp->snd_una; if (SEQ_LEQ((seq_out + len), snd_una)) { /* Are sending an old segment to induce an ack (keep-alive)? */ return; } if (SEQ_LT(seq_out, snd_una)) { /* huh? should we panic? */ uint32_t end; end = seq_out + len; seq_out = snd_una; len = end - seq_out; } snd_max = tp->snd_max; if (th_flags & (TH_SYN | TH_FIN)) { /* * The call to rack_log_output is made before bumping * snd_max. This means we can record one extra byte on a SYN * or FIN if seq_out is adding more on and a FIN is present * (and we are not resending). */ if (th_flags & TH_SYN) len++; if (th_flags & TH_FIN) len++; if (SEQ_LT(snd_max, tp->snd_nxt)) { /* * The add/update as not been done for the FIN/SYN * yet. */ snd_max = tp->snd_nxt; } } if (len == 0) { /* We don't log zero window probes */ return; } rack->r_ctl.rc_time_last_sent = ts; if (IN_RECOVERY(tp->t_flags)) { rack->r_ctl.rc_prr_out += len; } /* First question is it a retransmission? */ if (seq_out == snd_max) { again: rsm = rack_alloc(rack); if (rsm == NULL) { /* * Hmm out of memory and the tcb got destroyed while * we tried to wait. */ #ifdef INVARIANTS panic("Out of memory when we should not be rack:%p", rack); #endif return; } if (th_flags & TH_FIN) { rsm->r_flags = RACK_HAS_FIN; } else { rsm->r_flags = 0; } rsm->r_tim_lastsent[0] = ts; rsm->r_rtr_cnt = 1; rsm->r_rtr_bytes = 0; if (th_flags & TH_SYN) { /* The data space is one beyond snd_una */ rsm->r_start = seq_out + 1; rsm->r_end = rsm->r_start + (len - 1); } else { /* Normal case */ rsm->r_start = seq_out; rsm->r_end = rsm->r_start + len; } rsm->r_sndcnt = 0; TAILQ_INSERT_TAIL(&rack->r_ctl.rc_map, rsm, r_next); TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext); rsm->r_in_tmap = 1; return; } /* * If we reach here its a retransmission and we need to find it. */ more: if (hintrsm && (hintrsm->r_start == seq_out)) { rsm = hintrsm; hintrsm = NULL; } else if (rack->r_ctl.rc_next) { /* We have a hint from a previous run */ rsm = rack->r_ctl.rc_next; } else { /* No hints sorry */ rsm = NULL; } if ((rsm) && (rsm->r_start == seq_out)) { /* * We used rc_next or hintrsm to retransmit, hopefully the * likely case. */ seq_out = rack_update_entry(tp, rack, rsm, ts, &len); if (len == 0) { return; } else { goto more; } } /* Ok it was not the last pointer go through it the hard way. */ TAILQ_FOREACH(rsm, &rack->r_ctl.rc_map, r_next) { if (rsm->r_start == seq_out) { seq_out = rack_update_entry(tp, rack, rsm, ts, &len); rack->r_ctl.rc_next = TAILQ_NEXT(rsm, r_next); if (len == 0) { return; } else { continue; } } if (SEQ_GEQ(seq_out, rsm->r_start) && SEQ_LT(seq_out, rsm->r_end)) { /* Transmitted within this piece */ /* * Ok we must split off the front and then let the * update do the rest */ nrsm = rack_alloc(rack); if (nrsm == NULL) { #ifdef INVARIANTS panic("Ran out of memory that was preallocated? rack:%p", rack); #endif rack_update_rsm(tp, rack, rsm, ts); return; } /* * copy rsm to nrsm and then trim the front of rsm * to not include this part. */ nrsm->r_start = seq_out; nrsm->r_end = rsm->r_end; nrsm->r_rtr_cnt = rsm->r_rtr_cnt; nrsm->r_flags = rsm->r_flags; nrsm->r_sndcnt = rsm->r_sndcnt; nrsm->r_rtr_bytes = 0; for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) { nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx]; } rsm->r_end = nrsm->r_start; TAILQ_INSERT_AFTER(&rack->r_ctl.rc_map, rsm, nrsm, r_next); if (rsm->r_in_tmap) { TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext); nrsm->r_in_tmap = 1; } rsm->r_flags &= (~RACK_HAS_FIN); seq_out = rack_update_entry(tp, rack, nrsm, ts, &len); if (len == 0) { return; } } } /* * Hmm not found in map did they retransmit both old and on into the * new? */ if (seq_out == tp->snd_max) { goto again; } else if (SEQ_LT(seq_out, tp->snd_max)) { #ifdef INVARIANTS printf("seq_out:%u len:%d snd_una:%u snd_max:%u -- but rsm not found?\n", seq_out, len, tp->snd_una, tp->snd_max); printf("Starting Dump of all rack entries\n"); TAILQ_FOREACH(rsm, &rack->r_ctl.rc_map, r_next) { printf("rsm:%p start:%u end:%u\n", rsm, rsm->r_start, rsm->r_end); } printf("Dump complete\n"); panic("seq_out not found rack:%p tp:%p", rack, tp); #endif } else { #ifdef INVARIANTS /* * Hmm beyond sndmax? (only if we are using the new rtt-pack * flag) */ panic("seq_out:%u(%d) is beyond snd_max:%u tp:%p", seq_out, len, tp->snd_max, tp); #endif } } /* * Record one of the RTT updates from an ack into * our sample structure. */ static void tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt) { if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) || (rack->r_ctl.rack_rs.rs_rtt_lowest > rtt)) { rack->r_ctl.rack_rs.rs_rtt_lowest = rtt; } if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) || (rack->r_ctl.rack_rs.rs_rtt_highest < rtt)) { rack->r_ctl.rack_rs.rs_rtt_highest = rtt; } rack->r_ctl.rack_rs.rs_flags = RACK_RTT_VALID; rack->r_ctl.rack_rs.rs_rtt_tot += rtt; rack->r_ctl.rack_rs.rs_rtt_cnt++; } /* * Collect new round-trip time estimate * and update averages and current timeout. */ static void tcp_rack_xmit_timer_commit(struct tcp_rack *rack, struct tcpcb *tp) { int32_t delta; uint32_t o_srtt, o_var; int32_t rtt; if (rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) /* No valid sample */ return; if (rack->r_ctl.rc_rate_sample_method == USE_RTT_LOW) { /* We are to use the lowest RTT seen in a single ack */ rtt = rack->r_ctl.rack_rs.rs_rtt_lowest; } else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_HIGH) { /* We are to use the highest RTT seen in a single ack */ rtt = rack->r_ctl.rack_rs.rs_rtt_highest; } else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_AVG) { /* We are to use the average RTT seen in a single ack */ rtt = (int32_t)(rack->r_ctl.rack_rs.rs_rtt_tot / (uint64_t)rack->r_ctl.rack_rs.rs_rtt_cnt); } else { #ifdef INVARIANTS panic("Unknown rtt variant %d", rack->r_ctl.rc_rate_sample_method); #endif return; } if (rtt == 0) rtt = 1; rack_log_rtt_sample(rack, rtt); o_srtt = tp->t_srtt; o_var = tp->t_rttvar; rack = (struct tcp_rack *)tp->t_fb_ptr; if (tp->t_srtt != 0) { /* * srtt is stored as fixed point with 5 bits after the * binary point (i.e., scaled by 8). The following magic is * equivalent to the smoothing algorithm in rfc793 with an * alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed point). * Adjust rtt to origin 0. */ delta = ((rtt - 1) << TCP_DELTA_SHIFT) - (tp->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT)); tp->t_srtt += delta; if (tp->t_srtt <= 0) tp->t_srtt = 1; /* * We accumulate a smoothed rtt variance (actually, a * smoothed mean difference), then set the retransmit timer * to smoothed rtt + 4 times the smoothed variance. rttvar * is stored as fixed point with 4 bits after the binary * point (scaled by 16). The following is equivalent to * rfc793 smoothing with an alpha of .75 (rttvar = * rttvar*3/4 + |delta| / 4). This replaces rfc793's * wired-in beta. */ if (delta < 0) delta = -delta; delta -= tp->t_rttvar >> (TCP_RTTVAR_SHIFT - TCP_DELTA_SHIFT); tp->t_rttvar += delta; if (tp->t_rttvar <= 0) tp->t_rttvar = 1; if (tp->t_rttbest > tp->t_srtt + tp->t_rttvar) tp->t_rttbest = tp->t_srtt + tp->t_rttvar; } else { /* * No rtt measurement yet - use the unsmoothed rtt. Set the * variance to half the rtt (so our first retransmit happens * at 3*rtt). */ tp->t_srtt = rtt << TCP_RTT_SHIFT; tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1); tp->t_rttbest = tp->t_srtt + tp->t_rttvar; } TCPSTAT_INC(tcps_rttupdated); rack_log_rtt_upd(tp, rack, rtt, o_srtt, o_var); tp->t_rttupdated++; #ifdef NETFLIX_STATS stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, rtt)); #endif tp->t_rxtshift = 0; /* * the retransmit should happen at rtt + 4 * rttvar. Because of the * way we do the smoothing, srtt and rttvar will each average +1/2 * tick of bias. When we compute the retransmit timer, we want 1/2 * tick of rounding and 1 extra tick because of +-1/2 tick * uncertainty in the firing of the timer. The bias will give us * exactly the 1.5 tick we need. But, because the bias is * statistical, we have to test that we don't drop below the minimum * feasible timer (which is 2 ticks). */ TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), max(MSEC_2_TICKS(rack_rto_min), rtt + 2), MSEC_2_TICKS(rack_rto_max)); tp->t_softerror = 0; } static void rack_earlier_retran(struct tcpcb *tp, struct rack_sendmap *rsm, uint32_t t, uint32_t cts) { /* * For this RSM, we acknowledged the data from a previous * transmission, not the last one we made. This means we did a false * retransmit. */ struct tcp_rack *rack; if (rsm->r_flags & RACK_HAS_FIN) { /* * The sending of the FIN often is multiple sent when we * have everything outstanding ack'd. We ignore this case * since its over now. */ return; } if (rsm->r_flags & RACK_TLP) { /* * We expect TLP's to have this occur. */ return; } rack = (struct tcp_rack *)tp->t_fb_ptr; /* should we undo cc changes and exit recovery? */ if (IN_RECOVERY(tp->t_flags)) { if (rack->r_ctl.rc_rsm_start == rsm->r_start) { /* * Undo what we ratched down and exit recovery if * possible */ EXIT_RECOVERY(tp->t_flags); tp->snd_recover = tp->snd_una; if (rack->r_ctl.rc_cwnd_at > tp->snd_cwnd) tp->snd_cwnd = rack->r_ctl.rc_cwnd_at; if (rack->r_ctl.rc_ssthresh_at > tp->snd_ssthresh) tp->snd_ssthresh = rack->r_ctl.rc_ssthresh_at; } } if (rsm->r_flags & RACK_WAS_SACKPASS) { /* * We retransmitted based on a sack and the earlier * retransmission ack'd it - re-ordering is occuring. */ counter_u64_add(rack_reorder_seen, 1); rack->r_ctl.rc_reorder_ts = cts; } counter_u64_add(rack_badfr, 1); counter_u64_add(rack_badfr_bytes, (rsm->r_end - rsm->r_start)); } static int rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type) { int32_t i; uint32_t t; if (rsm->r_flags & RACK_ACKED) /* Already done */ return (0); if ((rsm->r_rtr_cnt == 1) || ((ack_type == CUM_ACKED) && (to->to_flags & TOF_TS) && (to->to_tsecr) && (rsm->r_tim_lastsent[rsm->r_rtr_cnt - 1] == to->to_tsecr)) ) { /* * We will only find a matching timestamp if its cum-acked. * But if its only one retransmission its for-sure matching * :-) */ t = cts - rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)]; if ((int)t <= 0) t = 1; if (!tp->t_rttlow || tp->t_rttlow > t) tp->t_rttlow = t; if (!rack->r_ctl.rc_rack_min_rtt || SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) { rack->r_ctl.rc_rack_min_rtt = t; if (rack->r_ctl.rc_rack_min_rtt == 0) { rack->r_ctl.rc_rack_min_rtt = 1; } } tcp_rack_xmit_timer(rack, TCP_TS_TO_TICKS(t) + 1); if ((rsm->r_flags & RACK_TLP) && (!IN_RECOVERY(tp->t_flags))) { /* Segment was a TLP and our retrans matched */ if (rack->r_ctl.rc_tlp_cwnd_reduce) { rack->r_ctl.rc_rsm_start = tp->snd_max; rack->r_ctl.rc_cwnd_at = tp->snd_cwnd; rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh; rack_cong_signal(tp, NULL, CC_NDUPACK); /* * When we enter recovery we need to assure * we send one packet. */ rack->r_ctl.rc_prr_sndcnt = tp->t_maxseg; } else rack->r_ctl.rc_tlp_rtx_out = 0; } if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) { /* New more recent rack_tmit_time */ rack->r_ctl.rc_rack_tmit_time = rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)]; rack->rc_rack_rtt = t; } return (1); } /* * We clear the soft/rxtshift since we got an ack. * There is no assurance we will call the commit() function * so we need to clear these to avoid incorrect handling. */ tp->t_rxtshift = 0; tp->t_softerror = 0; if ((to->to_flags & TOF_TS) && (ack_type == CUM_ACKED) && (to->to_tsecr) && ((rsm->r_flags & (RACK_DEFERRED | RACK_OVERMAX)) == 0)) { /* * Now which timestamp does it match? In this block the ACK * must be coming from a previous transmission. */ for (i = 0; i < rsm->r_rtr_cnt; i++) { if (rsm->r_tim_lastsent[i] == to->to_tsecr) { t = cts - rsm->r_tim_lastsent[i]; if ((int)t <= 0) t = 1; if ((i + 1) < rsm->r_rtr_cnt) { /* Likely */ rack_earlier_retran(tp, rsm, t, cts); } if (!tp->t_rttlow || tp->t_rttlow > t) tp->t_rttlow = t; if (!rack->r_ctl.rc_rack_min_rtt || SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) { rack->r_ctl.rc_rack_min_rtt = t; if (rack->r_ctl.rc_rack_min_rtt == 0) { rack->r_ctl.rc_rack_min_rtt = 1; } } /* * Note the following calls to * tcp_rack_xmit_timer() are being commented * out for now. They give us no more accuracy * and often lead to a wrong choice. We have * enough samples that have not been * retransmitted. I leave the commented out * code in here in case in the future we * decide to add it back (though I can't forsee * doing that). That way we will easily see * where they need to be placed. */ if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) { /* New more recent rack_tmit_time */ rack->r_ctl.rc_rack_tmit_time = rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)]; rack->rc_rack_rtt = t; } return (1); } } goto ts_not_found; } else { /* * Ok its a SACK block that we retransmitted. or a windows * machine without timestamps. We can tell nothing from the * time-stamp since its not there or the time the peer last * recieved a segment that moved forward its cum-ack point. */ ts_not_found: i = rsm->r_rtr_cnt - 1; t = cts - rsm->r_tim_lastsent[i]; if ((int)t <= 0) t = 1; if (rack->r_ctl.rc_rack_min_rtt && SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) { /* * We retransmitted and the ack came back in less * than the smallest rtt we have observed. We most * likey did an improper retransmit as outlined in * 4.2 Step 3 point 2 in the rack-draft. */ i = rsm->r_rtr_cnt - 2; t = cts - rsm->r_tim_lastsent[i]; rack_earlier_retran(tp, rsm, t, cts); } else if (rack->r_ctl.rc_rack_min_rtt) { /* * We retransmitted it and the retransmit did the * job. */ if (!rack->r_ctl.rc_rack_min_rtt || SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) { rack->r_ctl.rc_rack_min_rtt = t; if (rack->r_ctl.rc_rack_min_rtt == 0) { rack->r_ctl.rc_rack_min_rtt = 1; } } if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, rsm->r_tim_lastsent[i])) { /* New more recent rack_tmit_time */ rack->r_ctl.rc_rack_tmit_time = rsm->r_tim_lastsent[i]; rack->rc_rack_rtt = t; } return (1); } } return (0); } /* * Mark the SACK_PASSED flag on all entries prior to rsm send wise. */ static void rack_log_sack_passed(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm) { struct rack_sendmap *nrsm; uint32_t ts; int32_t idx; idx = rsm->r_rtr_cnt - 1; ts = rsm->r_tim_lastsent[idx]; nrsm = rsm; TAILQ_FOREACH_REVERSE_FROM(nrsm, &rack->r_ctl.rc_tmap, rack_head, r_tnext) { if (nrsm == rsm) { /* Skip orginal segment he is acked */ continue; } if (nrsm->r_flags & RACK_ACKED) { /* Skip ack'd segments */ continue; } idx = nrsm->r_rtr_cnt - 1; if (ts == nrsm->r_tim_lastsent[idx]) { /* * For this case lets use seq no, if we sent in a * big block (TSO) we would have a bunch of segments * sent at the same time. * * We would only get a report if its SEQ is earlier. * If we have done multiple retransmits the times * would not be equal. */ if (SEQ_LT(nrsm->r_start, rsm->r_start)) { nrsm->r_flags |= RACK_SACK_PASSED; nrsm->r_flags &= ~RACK_WAS_SACKPASS; } } else { /* * Here they were sent at different times, not a big * block. Since we transmitted this one later and * see it sack'd then this must also be missing (or * we would have gotten a sack block for it) */ nrsm->r_flags |= RACK_SACK_PASSED; nrsm->r_flags &= ~RACK_WAS_SACKPASS; } } } static uint32_t rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack, struct sackblk *sack, struct tcpopt *to, struct rack_sendmap **prsm, uint32_t cts) { int32_t idx; int32_t times = 0; uint32_t start, end, changed = 0; struct rack_sendmap *rsm, *nrsm; int32_t used_ref = 1; start = sack->start; end = sack->end; rsm = *prsm; if (rsm && SEQ_LT(start, rsm->r_start)) { TAILQ_FOREACH_REVERSE_FROM(rsm, &rack->r_ctl.rc_map, rack_head, r_next) { if (SEQ_GEQ(start, rsm->r_start) && SEQ_LT(start, rsm->r_end)) { goto do_rest_ofb; } } } if (rsm == NULL) { start_at_beginning: rsm = NULL; used_ref = 0; } /* First lets locate the block where this guy is */ TAILQ_FOREACH_FROM(rsm, &rack->r_ctl.rc_map, r_next) { if (SEQ_GEQ(start, rsm->r_start) && SEQ_LT(start, rsm->r_end)) { break; } } do_rest_ofb: if (rsm == NULL) { /* * This happens when we get duplicate sack blocks with the * same end. For example SACK 4: 100 SACK 3: 100 The sort * will not change there location so we would just start at * the end of the first one and get lost. */ if (tp->t_flags & TF_SENTFIN) { /* * Check to see if we have not logged the FIN that * went out. */ nrsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_map, rack_sendmap, r_next); if (nrsm && (nrsm->r_end + 1) == tp->snd_max) { /* * Ok we did not get the FIN logged. */ nrsm->r_end++; rsm = nrsm; goto do_rest_ofb; } } if (times == 1) { #ifdef INVARIANTS panic("tp:%p rack:%p sack:%p to:%p prsm:%p", tp, rack, sack, to, prsm); #else goto out; #endif } times++; counter_u64_add(rack_sack_proc_restart, 1); goto start_at_beginning; } /* Ok we have an ACK for some piece of rsm */ if (rsm->r_start != start) { /* * Need to split this in two pieces the before and after. */ nrsm = rack_alloc(rack); if (nrsm == NULL) { /* * failed XXXrrs what can we do but loose the sack * info? */ goto out; } nrsm->r_start = start; nrsm->r_rtr_bytes = 0; nrsm->r_end = rsm->r_end; nrsm->r_rtr_cnt = rsm->r_rtr_cnt; nrsm->r_flags = rsm->r_flags; nrsm->r_sndcnt = rsm->r_sndcnt; for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) { nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx]; } rsm->r_end = nrsm->r_start; TAILQ_INSERT_AFTER(&rack->r_ctl.rc_map, rsm, nrsm, r_next); if (rsm->r_in_tmap) { TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext); nrsm->r_in_tmap = 1; } rsm->r_flags &= (~RACK_HAS_FIN); rsm = nrsm; } if (SEQ_GEQ(end, rsm->r_end)) { /* * The end of this block is either beyond this guy or right * at this guy. */ if ((rsm->r_flags & RACK_ACKED) == 0) { rack_update_rtt(tp, rack, rsm, to, cts, SACKED); changed += (rsm->r_end - rsm->r_start); rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start); rack_log_sack_passed(tp, rack, rsm); /* Is Reordering occuring? */ if (rsm->r_flags & RACK_SACK_PASSED) { counter_u64_add(rack_reorder_seen, 1); rack->r_ctl.rc_reorder_ts = cts; } rsm->r_flags |= RACK_ACKED; rsm->r_flags &= ~RACK_TLP; if (rsm->r_in_tmap) { TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext); rsm->r_in_tmap = 0; } } if (end == rsm->r_end) { /* This block only - done */ goto out; } /* There is more not coverend by this rsm move on */ start = rsm->r_end; nrsm = TAILQ_NEXT(rsm, r_next); rsm = nrsm; times = 0; goto do_rest_ofb; } /* Ok we need to split off this one at the tail */ nrsm = rack_alloc(rack); if (nrsm == NULL) { /* failed rrs what can we do but loose the sack info? */ goto out; } /* Clone it */ nrsm->r_start = end; nrsm->r_end = rsm->r_end; nrsm->r_rtr_bytes = 0; nrsm->r_rtr_cnt = rsm->r_rtr_cnt; nrsm->r_flags = rsm->r_flags; nrsm->r_sndcnt = rsm->r_sndcnt; for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) { nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx]; } /* The sack block does not cover this guy fully */ rsm->r_flags &= (~RACK_HAS_FIN); rsm->r_end = end; TAILQ_INSERT_AFTER(&rack->r_ctl.rc_map, rsm, nrsm, r_next); if (rsm->r_in_tmap) { TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext); nrsm->r_in_tmap = 1; } if (rsm->r_flags & RACK_ACKED) { /* Been here done that */ goto out; } rack_update_rtt(tp, rack, rsm, to, cts, SACKED); changed += (rsm->r_end - rsm->r_start); rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start); rack_log_sack_passed(tp, rack, rsm); /* Is Reordering occuring? */ if (rsm->r_flags & RACK_SACK_PASSED) { counter_u64_add(rack_reorder_seen, 1); rack->r_ctl.rc_reorder_ts = cts; } rsm->r_flags |= RACK_ACKED; rsm->r_flags &= ~RACK_TLP; if (rsm->r_in_tmap) { TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext); rsm->r_in_tmap = 0; } out: if (used_ref == 0) { counter_u64_add(rack_sack_proc_all, 1); } else { counter_u64_add(rack_sack_proc_short, 1); } /* Save off where we last were */ if (rsm) rack->r_ctl.rc_sacklast = TAILQ_NEXT(rsm, r_next); else rack->r_ctl.rc_sacklast = NULL; *prsm = rsm; return (changed); } static void inline rack_peer_reneges(struct tcp_rack *rack, struct rack_sendmap *rsm, tcp_seq th_ack) { struct rack_sendmap *tmap; tmap = NULL; while (rsm && (rsm->r_flags & RACK_ACKED)) { /* Its no longer sacked, mark it so */ rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start); #ifdef INVARIANTS if (rsm->r_in_tmap) { panic("rack:%p rsm:%p flags:0x%x in tmap?", rack, rsm, rsm->r_flags); } #endif rsm->r_flags &= ~(RACK_ACKED|RACK_SACK_PASSED|RACK_WAS_SACKPASS); /* Rebuild it into our tmap */ if (tmap == NULL) { TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext); tmap = rsm; } else { TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, tmap, rsm, r_tnext); tmap = rsm; } tmap->r_in_tmap = 1; rsm = TAILQ_NEXT(rsm, r_next); } /* * Now lets possibly clear the sack filter so we start * recognizing sacks that cover this area. */ if (rack_use_sack_filter) sack_filter_clear(&rack->r_ctl.rack_sf, th_ack); } static void rack_log_ack(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th) { uint32_t changed, last_seq, entered_recovery = 0; struct tcp_rack *rack; struct rack_sendmap *rsm; struct sackblk sack, sack_blocks[TCP_MAX_SACK + 1]; register uint32_t th_ack; int32_t i, j, k, num_sack_blks = 0; uint32_t cts, acked, ack_point, sack_changed = 0; INP_WLOCK_ASSERT(tp->t_inpcb); if (th->th_flags & TH_RST) { /* We don't log resets */ return; } rack = (struct tcp_rack *)tp->t_fb_ptr; cts = tcp_ts_getticks(); rsm = TAILQ_FIRST(&rack->r_ctl.rc_map); changed = 0; th_ack = th->th_ack; if (SEQ_GT(th_ack, tp->snd_una)) { rack_log_progress_event(rack, tp, ticks, PROGRESS_UPDATE, __LINE__); tp->t_acktime = ticks; } if (rsm && SEQ_GT(th_ack, rsm->r_start)) changed = th_ack - rsm->r_start; if (changed) { /* * The ACK point is advancing to th_ack, we must drop off * the packets in the rack log and calculate any eligble * RTT's. */ rack->r_wanted_output++; more: rsm = TAILQ_FIRST(&rack->r_ctl.rc_map); if (rsm == NULL) { if ((th_ack - 1) == tp->iss) { /* * For the SYN incoming case we will not * have called tcp_output for the sending of * the SYN, so there will be no map. All * other cases should probably be a panic. */ goto proc_sack; } if (tp->t_flags & TF_SENTFIN) { /* if we send a FIN we will not hav a map */ goto proc_sack; } #ifdef INVARIANTS panic("No rack map tp:%p for th:%p state:%d rack:%p snd_una:%u snd_max:%u snd_nxt:%u chg:%d\n", tp, th, tp->t_state, rack, tp->snd_una, tp->snd_max, tp->snd_nxt, changed); #endif goto proc_sack; } if (SEQ_LT(th_ack, rsm->r_start)) { /* Huh map is missing this */ #ifdef INVARIANTS printf("Rack map starts at r_start:%u for th_ack:%u huh? ts:%d rs:%d\n", rsm->r_start, th_ack, tp->t_state, rack->r_state); #endif goto proc_sack; } rack_update_rtt(tp, rack, rsm, to, cts, CUM_ACKED); /* Now do we consume the whole thing? */ if (SEQ_GEQ(th_ack, rsm->r_end)) { /* Its all consumed. */ uint32_t left; rack->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes; rsm->r_rtr_bytes = 0; TAILQ_REMOVE(&rack->r_ctl.rc_map, rsm, r_next); if (rsm->r_in_tmap) { TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext); rsm->r_in_tmap = 0; } if (rack->r_ctl.rc_next == rsm) { /* scoot along the marker */ rack->r_ctl.rc_next = TAILQ_FIRST(&rack->r_ctl.rc_map); } if (rsm->r_flags & RACK_ACKED) { /* * It was acked on the scoreboard -- remove * it from total */ rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start); } else if (rsm->r_flags & RACK_SACK_PASSED) { /* * There are acked segments ACKED on the * scoreboard further up. We are seeing * reordering. */ counter_u64_add(rack_reorder_seen, 1); rsm->r_flags |= RACK_ACKED; rack->r_ctl.rc_reorder_ts = cts; } left = th_ack - rsm->r_end; if (rsm->r_rtr_cnt > 1) { /* * Technically we should make r_rtr_cnt be * monotonicly increasing and just mod it to * the timestamp it is replacing.. that way * we would have the last 3 retransmits. Now * rc_loss_count will be wrong if we * retransmit something more than 2 times in * recovery :( */ rack->r_ctl.rc_loss_count += (rsm->r_rtr_cnt - 1); } /* Free back to zone */ rack_free(rack, rsm); if (left) { goto more; } goto proc_sack; } if (rsm->r_flags & RACK_ACKED) { /* * It was acked on the scoreboard -- remove it from * total for the part being cum-acked. */ rack->r_ctl.rc_sacked -= (th_ack - rsm->r_start); } rack->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes; rsm->r_rtr_bytes = 0; rsm->r_start = th_ack; } proc_sack: /* Check for reneging */ rsm = TAILQ_FIRST(&rack->r_ctl.rc_map); if (rsm && (rsm->r_flags & RACK_ACKED) && (th_ack == rsm->r_start)) { /* * The peer has moved snd_una up to * the edge of this send, i.e. one * that it had previously acked. The only * way that can be true if the peer threw * away data (space issues) that it had * previously sacked (else it would have * given us snd_una up to (rsm->r_end). * We need to undo the acked markings here. * * Note we have to look to make sure th_ack is * our rsm->r_start in case we get an old ack * where th_ack is behind snd_una. */ rack_peer_reneges(rack, rsm, th->th_ack); } if ((to->to_flags & TOF_SACK) == 0) { /* We are done nothing left to log */ goto out; } rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_map, rack_sendmap, r_next); if (rsm) { last_seq = rsm->r_end; } else { last_seq = tp->snd_max; } /* Sack block processing */ if (SEQ_GT(th_ack, tp->snd_una)) ack_point = th_ack; else ack_point = tp->snd_una; for (i = 0; i < to->to_nsacks; i++) { bcopy((to->to_sacks + i * TCPOLEN_SACK), &sack, sizeof(sack)); sack.start = ntohl(sack.start); sack.end = ntohl(sack.end); if (SEQ_GT(sack.end, sack.start) && SEQ_GT(sack.start, ack_point) && SEQ_LT(sack.start, tp->snd_max) && SEQ_GT(sack.end, ack_point) && SEQ_LEQ(sack.end, tp->snd_max)) { if ((rack->r_ctl.rc_num_maps_alloced > rack_sack_block_limit) && (SEQ_LT(sack.end, last_seq)) && ((sack.end - sack.start) < (tp->t_maxseg / 8))) { /* * Not the last piece and its smaller than * 1/8th of a MSS. We ignore this. */ counter_u64_add(rack_runt_sacks, 1); continue; } sack_blocks[num_sack_blks] = sack; num_sack_blks++; #ifdef NETFLIX_STATS } else if (SEQ_LEQ(sack.start, th_ack) && SEQ_LEQ(sack.end, th_ack)) { /* * Its a D-SACK block. */ tcp_record_dsack(sack.start, sack.end); #endif } } if (num_sack_blks == 0) goto out; /* * Sort the SACK blocks so we can update the rack scoreboard with * just one pass. */ if (rack_use_sack_filter) { num_sack_blks = sack_filter_blks(&rack->r_ctl.rack_sf, sack_blocks, num_sack_blks, th->th_ack); } if (num_sack_blks < 2) { goto do_sack_work; } /* Sort the sacks */ for (i = 0; i < num_sack_blks; i++) { for (j = i + 1; j < num_sack_blks; j++) { if (SEQ_GT(sack_blocks[i].end, sack_blocks[j].end)) { sack = sack_blocks[i]; sack_blocks[i] = sack_blocks[j]; sack_blocks[j] = sack; } } } /* * Now are any of the sack block ends the same (yes some * implememtations send these)? */ again: if (num_sack_blks > 1) { for (i = 0; i < num_sack_blks; i++) { for (j = i + 1; j < num_sack_blks; j++) { if (sack_blocks[i].end == sack_blocks[j].end) { /* * Ok these two have the same end we * want the smallest end and then * throw away the larger and start * again. */ if (SEQ_LT(sack_blocks[j].start, sack_blocks[i].start)) { /* * The second block covers * more area use that */ sack_blocks[i].start = sack_blocks[j].start; } /* * Now collapse out the dup-sack and * lower the count */ for (k = (j + 1); k < num_sack_blks; k++) { sack_blocks[j].start = sack_blocks[k].start; sack_blocks[j].end = sack_blocks[k].end; j++; } num_sack_blks--; goto again; } } } } do_sack_work: rsm = rack->r_ctl.rc_sacklast; for (i = 0; i < num_sack_blks; i++) { acked = rack_proc_sack_blk(tp, rack, &sack_blocks[i], to, &rsm, cts); if (acked) { rack->r_wanted_output++; changed += acked; sack_changed += acked; } } out: if (changed) { /* Something changed cancel the rack timer */ rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); } if ((sack_changed) && (!IN_RECOVERY(tp->t_flags))) { /* * Ok we have a high probability that we need to go in to * recovery since we have data sack'd */ struct rack_sendmap *rsm; uint32_t tsused; tsused = tcp_ts_getticks(); rsm = tcp_rack_output(tp, rack, tsused); if (rsm) { /* Enter recovery */ rack->r_ctl.rc_rsm_start = rsm->r_start; rack->r_ctl.rc_cwnd_at = tp->snd_cwnd; rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh; entered_recovery = 1; rack_cong_signal(tp, NULL, CC_NDUPACK); /* * When we enter recovery we need to assure we send * one packet. */ rack->r_ctl.rc_prr_sndcnt = tp->t_maxseg; rack->r_timer_override = 1; } } if (IN_RECOVERY(tp->t_flags) && (entered_recovery == 0)) { /* Deal with changed an PRR here (in recovery only) */ uint32_t pipe, snd_una; rack->r_ctl.rc_prr_delivered += changed; /* Compute prr_sndcnt */ if (SEQ_GT(tp->snd_una, th_ack)) { snd_una = tp->snd_una; } else { snd_una = th_ack; } pipe = ((tp->snd_max - snd_una) - rack->r_ctl.rc_sacked) + rack->r_ctl.rc_holes_rxt; if (pipe > tp->snd_ssthresh) { long sndcnt; sndcnt = rack->r_ctl.rc_prr_delivered * tp->snd_ssthresh; if (rack->r_ctl.rc_prr_recovery_fs > 0) sndcnt /= (long)rack->r_ctl.rc_prr_recovery_fs; else { rack->r_ctl.rc_prr_sndcnt = 0; sndcnt = 0; } sndcnt++; if (sndcnt > (long)rack->r_ctl.rc_prr_out) sndcnt -= rack->r_ctl.rc_prr_out; else sndcnt = 0; rack->r_ctl.rc_prr_sndcnt = sndcnt; } else { uint32_t limit; if (rack->r_ctl.rc_prr_delivered > rack->r_ctl.rc_prr_out) limit = (rack->r_ctl.rc_prr_delivered - rack->r_ctl.rc_prr_out); else limit = 0; if (changed > limit) limit = changed; limit += tp->t_maxseg; if (tp->snd_ssthresh > pipe) { rack->r_ctl.rc_prr_sndcnt = min((tp->snd_ssthresh - pipe), limit); } else { rack->r_ctl.rc_prr_sndcnt = min(0, limit); } } if (rack->r_ctl.rc_prr_sndcnt >= tp->t_maxseg) { rack->r_timer_override = 1; } } } /* * Return value of 1, we do not need to call rack_process_data(). * return value of 0, rack_process_data can be called. * For ret_val if its 0 the TCP is locked, if its non-zero * its unlocked and probably unsafe to touch the TCB. */ static int rack_process_ack(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, uint32_t tiwin, int32_t tlen, int32_t * ofia, int32_t thflags, int32_t * ret_val) { int32_t ourfinisacked = 0; int32_t nsegs, acked_amount; int32_t acked; struct mbuf *mfree; struct tcp_rack *rack; int32_t recovery = 0; rack = (struct tcp_rack *)tp->t_fb_ptr; if (SEQ_GT(th->th_ack, tp->snd_max)) { rack_do_dropafterack(m, tp, th, thflags, tlen, ret_val); return (1); } if (SEQ_GEQ(th->th_ack, tp->snd_una) || to->to_nsacks) { rack_log_ack(tp, to, th); } if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) { /* * Old ack, behind (or duplicate to) the last one rcv'd * Note: Should mark reordering is occuring! We should also * look for sack blocks arriving e.g. ack 1, 4-4 then ack 1, * 3-3, 4-4 would be reording. As well as ack 1, 3-3 ack 3 */ return (0); } /* * If we reach this point, ACK is not a duplicate, i.e., it ACKs * something we sent. */ if (tp->t_flags & TF_NEEDSYN) { /* * T/TCP: Connection was half-synchronized, and our SYN has * been ACK'd (so connection is now fully synchronized). Go * to non-starred state, increment snd_una for ACK of SYN, * and check if we can do window scaling. */ tp->t_flags &= ~TF_NEEDSYN; tp->snd_una++; /* Do window scaling? */ if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) == (TF_RCVD_SCALE | TF_REQ_SCALE)) { tp->rcv_scale = tp->request_r_scale; /* Send window already scaled. */ } } nsegs = max(1, m->m_pkthdr.lro_nsegs); INP_WLOCK_ASSERT(tp->t_inpcb); acked = BYTES_THIS_ACK(tp, th); TCPSTAT_ADD(tcps_rcvackpack, nsegs); TCPSTAT_ADD(tcps_rcvackbyte, acked); /* * If we just performed our first retransmit, and the ACK arrives * within our recovery window, then it was a mistake to do the * retransmit in the first place. Recover our original cwnd and * ssthresh, and proceed to transmit where we left off. */ if (tp->t_flags & TF_PREVVALID) { tp->t_flags &= ~TF_PREVVALID; if (tp->t_rxtshift == 1 && (int)(ticks - tp->t_badrxtwin) < 0) rack_cong_signal(tp, th, CC_RTO_ERR); } /* * If we have a timestamp reply, update smoothed round trip time. If * no timestamp is present but transmit timer is running and timed * sequence number was acked, update smoothed round trip time. Since * we now have an rtt measurement, cancel the timer backoff (cf., * Phil Karn's retransmit alg.). Recompute the initial retransmit * timer. * * Some boxes send broken timestamp replies during the SYN+ACK * phase, ignore timestamps of 0 or we could calculate a huge RTT * and blow up the retransmit timer. */ /* * If all outstanding data is acked, stop retransmit timer and * remember to restart (more output or persist). If there is more * data to be acked, restart retransmit timer, using current * (possibly backed-off) value. */ if (th->th_ack == tp->snd_max) { rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); rack->r_wanted_output++; } /* * If no data (only SYN) was ACK'd, skip rest of ACK processing. */ if (acked == 0) { if (ofia) *ofia = ourfinisacked; return (0); } if (rack->r_ctl.rc_early_recovery) { if (IN_FASTRECOVERY(tp->t_flags)) { if (SEQ_LT(th->th_ack, tp->snd_recover)) { tcp_rack_partialack(tp, th); } else { rack_post_recovery(tp, th); recovery = 1; } } } /* * Let the congestion control algorithm update congestion control * related information. This typically means increasing the * congestion window. */ rack_ack_received(tp, rack, th, nsegs, CC_ACK, recovery); SOCKBUF_LOCK(&so->so_snd); acked_amount = min(acked, (int)sbavail(&so->so_snd)); tp->snd_wnd -= acked_amount; mfree = sbcut_locked(&so->so_snd, acked_amount); if ((sbused(&so->so_snd) == 0) && (acked > acked_amount) && (tp->t_state >= TCPS_FIN_WAIT_1)) { ourfinisacked = 1; } /* NB: sowwakeup_locked() does an implicit unlock. */ sowwakeup_locked(so); m_freem(mfree); if (rack->r_ctl.rc_early_recovery == 0) { if (IN_FASTRECOVERY(tp->t_flags)) { if (SEQ_LT(th->th_ack, tp->snd_recover)) { tcp_rack_partialack(tp, th); } else { rack_post_recovery(tp, th); } } } tp->snd_una = th->th_ack; if (SEQ_GT(tp->snd_una, tp->snd_recover)) tp->snd_recover = tp->snd_una; if (SEQ_LT(tp->snd_nxt, tp->snd_una)) { tp->snd_nxt = tp->snd_una; } if (tp->snd_una == tp->snd_max) { /* Nothing left outstanding */ rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__); tp->t_acktime = 0; rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); /* Set need output so persist might get set */ rack->r_wanted_output++; if (rack_use_sack_filter) sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una); if ((tp->t_state >= TCPS_FIN_WAIT_1) && (sbavail(&so->so_snd) == 0) && (tp->t_flags2 & TF2_DROP_AF_DATA)) { /* * The socket was gone and the * peer sent data, time to * reset him. */ *ret_val = 1; tp = tcp_close(tp); rack_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, tlen); return (1); } } if (ofia) *ofia = ourfinisacked; return (0); } /* * Return value of 1, the TCB is unlocked and most * likely gone, return value of 0, the TCP is still * locked. */ static int rack_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt) { /* * Update window information. Don't look at window if no ACK: TAC's * send garbage on first SYN. */ int32_t nsegs; int32_t tfo_syn; struct tcp_rack *rack; rack = (struct tcp_rack *)tp->t_fb_ptr; INP_WLOCK_ASSERT(tp->t_inpcb); nsegs = max(1, m->m_pkthdr.lro_nsegs); if ((thflags & TH_ACK) && (SEQ_LT(tp->snd_wl1, th->th_seq) || (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) || (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) { /* keep track of pure window updates */ if (tlen == 0 && tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd) TCPSTAT_INC(tcps_rcvwinupd); tp->snd_wnd = tiwin; tp->snd_wl1 = th->th_seq; tp->snd_wl2 = th->th_ack; if (tp->snd_wnd > tp->max_sndwnd) tp->max_sndwnd = tp->snd_wnd; rack->r_wanted_output++; } else if (thflags & TH_ACK) { if ((tp->snd_wl2 == th->th_ack) && (tiwin < tp->snd_wnd)) { tp->snd_wnd = tiwin; tp->snd_wl1 = th->th_seq; tp->snd_wl2 = th->th_ack; } } /* Was persist timer active and now we have window space? */ if ((rack->rc_in_persist != 0) && tp->snd_wnd) { rack_exit_persist(tp, rack); tp->snd_nxt = tp->snd_max; /* Make sure we output to start the timer */ rack->r_wanted_output++; } if (tp->t_flags2 & TF2_DROP_AF_DATA) { m_freem(m); return (0); } /* * Process segments with URG. */ if ((thflags & TH_URG) && th->th_urp && TCPS_HAVERCVDFIN(tp->t_state) == 0) { /* * This is a kludge, but if we receive and accept random * urgent pointers, we'll crash in soreceive. It's hard to * imagine someone actually wanting to send this much urgent * data. */ SOCKBUF_LOCK(&so->so_rcv); if (th->th_urp + sbavail(&so->so_rcv) > sb_max) { th->th_urp = 0; /* XXX */ thflags &= ~TH_URG; /* XXX */ SOCKBUF_UNLOCK(&so->so_rcv); /* XXX */ goto dodata; /* XXX */ } /* * If this segment advances the known urgent pointer, then * mark the data stream. This should not happen in * CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since a * FIN has been received from the remote side. In these * states we ignore the URG. * * According to RFC961 (Assigned Protocols), the urgent * pointer points to the last octet of urgent data. We * continue, however, to consider it to indicate the first * octet of data past the urgent section as the original * spec states (in one of two places). */ if (SEQ_GT(th->th_seq + th->th_urp, tp->rcv_up)) { tp->rcv_up = th->th_seq + th->th_urp; so->so_oobmark = sbavail(&so->so_rcv) + (tp->rcv_up - tp->rcv_nxt) - 1; if (so->so_oobmark == 0) so->so_rcv.sb_state |= SBS_RCVATMARK; sohasoutofband(so); tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA); } SOCKBUF_UNLOCK(&so->so_rcv); /* * Remove out of band data so doesn't get presented to user. * This can happen independent of advancing the URG pointer, * but if two URG's are pending at once, some out-of-band * data may creep in... ick. */ if (th->th_urp <= (uint32_t) tlen && !(so->so_options & SO_OOBINLINE)) { /* hdr drop is delayed */ tcp_pulloutofband(so, th, m, drop_hdrlen); } } else { /* * If no out of band data is expected, pull receive urgent * pointer along with the receive window. */ if (SEQ_GT(tp->rcv_nxt, tp->rcv_up)) tp->rcv_up = tp->rcv_nxt; } dodata: /* XXX */ INP_WLOCK_ASSERT(tp->t_inpcb); /* * Process the segment text, merging it into the TCP sequencing * queue, and arranging for acknowledgment of receipt if necessary. * This process logically involves adjusting tp->rcv_wnd as data is * presented to the user (this happens in tcp_usrreq.c, case * PRU_RCVD). If a FIN has already been received on this connection * then we just ignore the text. */ tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) && IS_FASTOPEN(tp->t_flags)); if ((tlen || (thflags & TH_FIN) || tfo_syn) && TCPS_HAVERCVDFIN(tp->t_state) == 0) { tcp_seq save_start = th->th_seq; m_adj(m, drop_hdrlen); /* delayed header drop */ /* * Insert segment which includes th into TCP reassembly * queue with control block tp. Set thflags to whether * reassembly now includes a segment with FIN. This handles * the common case inline (segment is the next to be * received on an established connection, and the queue is * empty), avoiding linkage into and removal from the queue * and repetition of various conversions. Set DELACK for * segments received in order, but ack immediately when * segments are out of order (so fast retransmit can work). */ if (th->th_seq == tp->rcv_nxt && SEGQ_EMPTY(tp) && (TCPS_HAVEESTABLISHED(tp->t_state) || tfo_syn)) { if (DELAY_ACK(tp, tlen) || tfo_syn) { rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); tp->t_flags |= TF_DELACK; } else { rack->r_wanted_output++; tp->t_flags |= TF_ACKNOW; } tp->rcv_nxt += tlen; thflags = th->th_flags & TH_FIN; TCPSTAT_ADD(tcps_rcvpack, nsegs); TCPSTAT_ADD(tcps_rcvbyte, tlen); SOCKBUF_LOCK(&so->so_rcv); if (so->so_rcv.sb_state & SBS_CANTRCVMORE) m_freem(m); else sbappendstream_locked(&so->so_rcv, m, 0); /* NB: sorwakeup_locked() does an implicit unlock. */ sorwakeup_locked(so); } else { /* * XXX: Due to the header drop above "th" is * theoretically invalid by now. Fortunately * m_adj() doesn't actually frees any mbufs when * trimming from the head. */ thflags = tcp_reass(tp, th, &save_start, &tlen, m); tp->t_flags |= TF_ACKNOW; } if (tlen > 0) tcp_update_sack_list(tp, save_start, save_start + tlen); } else { m_freem(m); thflags &= ~TH_FIN; } /* * If FIN is received ACK the FIN and let the user know that the * connection is closing. */ if (thflags & TH_FIN) { if (TCPS_HAVERCVDFIN(tp->t_state) == 0) { socantrcvmore(so); /* * If connection is half-synchronized (ie NEEDSYN * flag on) then delay ACK, so it may be piggybacked * when SYN is sent. Otherwise, since we received a * FIN then no more input can be expected, send ACK * now. */ if (tp->t_flags & TF_NEEDSYN) { rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); tp->t_flags |= TF_DELACK; } else { tp->t_flags |= TF_ACKNOW; } tp->rcv_nxt++; } switch (tp->t_state) { /* * In SYN_RECEIVED and ESTABLISHED STATES enter the * CLOSE_WAIT state. */ case TCPS_SYN_RECEIVED: tp->t_starttime = ticks; /* FALLTHROUGH */ case TCPS_ESTABLISHED: rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); tcp_state_change(tp, TCPS_CLOSE_WAIT); break; /* * If still in FIN_WAIT_1 STATE FIN has not been * acked so enter the CLOSING state. */ case TCPS_FIN_WAIT_1: rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); tcp_state_change(tp, TCPS_CLOSING); break; /* * In FIN_WAIT_2 state enter the TIME_WAIT state, * starting the time-wait timer, turning off the * other standard timers. */ case TCPS_FIN_WAIT_2: rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); INP_INFO_RLOCK_ASSERT(&V_tcbinfo); tcp_twstart(tp); return (1); } } /* * Return any desired output. */ if ((tp->t_flags & TF_ACKNOW) || (sbavail(&so->so_snd) > (tp->snd_max - tp->snd_una))) { rack->r_wanted_output++; } INP_WLOCK_ASSERT(tp->t_inpcb); return (0); } /* * Here nothing is really faster, its just that we * have broken out the fast-data path also just like * the fast-ack. */ static int rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t nxt_pkt) { int32_t nsegs; int32_t newsize = 0; /* automatic sockbuf scaling */ struct tcp_rack *rack; #ifdef TCPDEBUG /* * The size of tcp_saveipgen must be the size of the max ip header, * now IPv6. */ u_char tcp_saveipgen[IP6_HDR_LEN]; struct tcphdr tcp_savetcp; short ostate = 0; #endif /* * If last ACK falls within this segment's sequence numbers, record * the timestamp. NOTE that the test is modified according to the * latest proposal of the tcplw@cray.com list (Braden 1993/04/26). */ if (__predict_false(th->th_seq != tp->rcv_nxt)) { return (0); } if (__predict_false(tp->snd_nxt != tp->snd_max)) { return (0); } if (tiwin && tiwin != tp->snd_wnd) { return (0); } if (__predict_false((tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN)))) { return (0); } if (__predict_false((to->to_flags & TOF_TS) && (TSTMP_LT(to->to_tsval, tp->ts_recent)))) { return (0); } if (__predict_false((th->th_ack != tp->snd_una))) { return (0); } if (__predict_false(tlen > sbspace(&so->so_rcv))) { return (0); } if ((to->to_flags & TOF_TS) != 0 && SEQ_LEQ(th->th_seq, tp->last_ack_sent)) { tp->ts_recent_age = tcp_ts_getticks(); tp->ts_recent = to->to_tsval; } rack = (struct tcp_rack *)tp->t_fb_ptr; /* * This is a pure, in-sequence data packet with nothing on the * reassembly queue and we have enough buffer space to take it. */ nsegs = max(1, m->m_pkthdr.lro_nsegs); /* Clean receiver SACK report if present */ if (tp->rcv_numsacks) tcp_clean_sackreport(tp); TCPSTAT_INC(tcps_preddat); tp->rcv_nxt += tlen; /* * Pull snd_wl1 up to prevent seq wrap relative to th_seq. */ tp->snd_wl1 = th->th_seq; /* * Pull rcv_up up to prevent seq wrap relative to rcv_nxt. */ tp->rcv_up = tp->rcv_nxt; TCPSTAT_ADD(tcps_rcvpack, nsegs); TCPSTAT_ADD(tcps_rcvbyte, tlen); #ifdef TCPDEBUG if (so->so_options & SO_DEBUG) tcp_trace(TA_INPUT, ostate, tp, (void *)tcp_saveipgen, &tcp_savetcp, 0); #endif newsize = tcp_autorcvbuf(m, th, so, tp, tlen); /* Add data to socket buffer. */ SOCKBUF_LOCK(&so->so_rcv); if (so->so_rcv.sb_state & SBS_CANTRCVMORE) { m_freem(m); } else { /* * Set new socket buffer size. Give up when limit is * reached. */ if (newsize) if (!sbreserve_locked(&so->so_rcv, newsize, so, NULL)) so->so_rcv.sb_flags &= ~SB_AUTOSIZE; m_adj(m, drop_hdrlen); /* delayed header drop */ sbappendstream_locked(&so->so_rcv, m, 0); rack_calc_rwin(so, tp); } /* NB: sorwakeup_locked() does an implicit unlock. */ sorwakeup_locked(so); if (DELAY_ACK(tp, tlen)) { rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); tp->t_flags |= TF_DELACK; } else { tp->t_flags |= TF_ACKNOW; rack->r_wanted_output++; } if ((tp->snd_una == tp->snd_max) && rack_use_sack_filter) sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una); return (1); } /* * This subfunction is used to try to highly optimize the * fast path. We again allow window updates that are * in sequence to remain in the fast-path. We also add * in the __predict's to attempt to help the compiler. * Note that if we return a 0, then we can *not* process * it and the caller should push the packet into the * slow-path. */ static int rack_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t nxt_pkt, uint32_t cts) { int32_t acked; int32_t nsegs; #ifdef TCPDEBUG /* * The size of tcp_saveipgen must be the size of the max ip header, * now IPv6. */ u_char tcp_saveipgen[IP6_HDR_LEN]; struct tcphdr tcp_savetcp; short ostate = 0; #endif struct tcp_rack *rack; if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) { /* Old ack, behind (or duplicate to) the last one rcv'd */ return (0); } if (__predict_false(SEQ_GT(th->th_ack, tp->snd_max))) { /* Above what we have sent? */ return (0); } if (__predict_false(tp->snd_nxt != tp->snd_max)) { /* We are retransmitting */ return (0); } if (__predict_false(tiwin == 0)) { /* zero window */ return (0); } if (__predict_false(tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN))) { /* We need a SYN or a FIN, unlikely.. */ return (0); } if ((to->to_flags & TOF_TS) && __predict_false(TSTMP_LT(to->to_tsval, tp->ts_recent))) { /* Timestamp is behind .. old ack with seq wrap? */ return (0); } if (__predict_false(IN_RECOVERY(tp->t_flags))) { /* Still recovering */ return (0); } rack = (struct tcp_rack *)tp->t_fb_ptr; if (rack->r_ctl.rc_sacked) { /* We have sack holes on our scoreboard */ return (0); } /* Ok if we reach here, we can process a fast-ack */ nsegs = max(1, m->m_pkthdr.lro_nsegs); rack_log_ack(tp, to, th); /* Did the window get updated? */ if (tiwin != tp->snd_wnd) { tp->snd_wnd = tiwin; tp->snd_wl1 = th->th_seq; if (tp->snd_wnd > tp->max_sndwnd) tp->max_sndwnd = tp->snd_wnd; } if ((rack->rc_in_persist != 0) && (tp->snd_wnd >= tp->t_maxseg)) { rack_exit_persist(tp, rack); } /* * If last ACK falls within this segment's sequence numbers, record * the timestamp. NOTE that the test is modified according to the * latest proposal of the tcplw@cray.com list (Braden 1993/04/26). */ if ((to->to_flags & TOF_TS) != 0 && SEQ_LEQ(th->th_seq, tp->last_ack_sent)) { tp->ts_recent_age = tcp_ts_getticks(); tp->ts_recent = to->to_tsval; } /* * This is a pure ack for outstanding data. */ TCPSTAT_INC(tcps_predack); /* * "bad retransmit" recovery. */ if (tp->t_flags & TF_PREVVALID) { tp->t_flags &= ~TF_PREVVALID; if (tp->t_rxtshift == 1 && (int)(ticks - tp->t_badrxtwin) < 0) rack_cong_signal(tp, th, CC_RTO_ERR); } /* * Recalculate the transmit timer / rtt. * * Some boxes send broken timestamp replies during the SYN+ACK * phase, ignore timestamps of 0 or we could calculate a huge RTT * and blow up the retransmit timer. */ acked = BYTES_THIS_ACK(tp, th); #ifdef TCP_HHOOK /* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */ hhook_run_tcp_est_in(tp, th, to); #endif TCPSTAT_ADD(tcps_rcvackpack, nsegs); TCPSTAT_ADD(tcps_rcvackbyte, acked); sbdrop(&so->so_snd, acked); /* * Let the congestion control algorithm update congestion control * related information. This typically means increasing the * congestion window. */ rack_ack_received(tp, rack, th, nsegs, CC_ACK, 0); tp->snd_una = th->th_ack; /* * Pull snd_wl2 up to prevent seq wrap relative to th_ack. */ tp->snd_wl2 = th->th_ack; tp->t_dupacks = 0; m_freem(m); /* ND6_HINT(tp); *//* Some progress has been made. */ /* * If all outstanding data are acked, stop retransmit timer, * otherwise restart timer using current (possibly backed-off) * value. If process is waiting for space, wakeup/selwakeup/signal. * If data are ready to send, let tcp_output decide between more * output or persist. */ #ifdef TCPDEBUG if (so->so_options & SO_DEBUG) tcp_trace(TA_INPUT, ostate, tp, (void *)tcp_saveipgen, &tcp_savetcp, 0); #endif if (tp->snd_una == tp->snd_max) { rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__); tp->t_acktime = 0; rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); } /* Wake up the socket if we have room to write more */ sowwakeup(so); if (sbavail(&so->so_snd)) { rack->r_wanted_output++; } return (1); } /* * Return value of 1, the TCB is unlocked and most * likely gone, return value of 0, the TCP is still * locked. */ static int rack_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt) { int32_t ret_val = 0; int32_t todrop; int32_t ourfinisacked = 0; rack_calc_rwin(so, tp); /* * If the state is SYN_SENT: if seg contains an ACK, but not for our * SYN, drop the input. if seg contains a RST, then drop the * connection. if seg does not contain SYN, then drop it. Otherwise * this is an acceptable SYN segment initialize tp->rcv_nxt and * tp->irs if seg contains ack then advance tp->snd_una if seg * contains an ECE and ECN support is enabled, the stream is ECN * capable. if SYN has been acked change to ESTABLISHED else * SYN_RCVD state arrange for segment to be acked (eventually) * continue processing rest of data/controls, beginning with URG */ if ((thflags & TH_ACK) && (SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) { rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } if ((thflags & (TH_ACK | TH_RST)) == (TH_ACK | TH_RST)) { TCP_PROBE5(connect__refused, NULL, tp, mtod(m, const char *), tp, th); tp = tcp_drop(tp, ECONNREFUSED); rack_do_drop(m, tp); return (1); } if (thflags & TH_RST) { rack_do_drop(m, tp); return (1); } if (!(thflags & TH_SYN)) { rack_do_drop(m, tp); return (1); } tp->irs = th->th_seq; tcp_rcvseqinit(tp); if (thflags & TH_ACK) { int tfo_partial = 0; TCPSTAT_INC(tcps_connects); soisconnected(so); #ifdef MAC mac_socketpeer_set_from_mbuf(m, so); #endif /* Do window scaling on this connection? */ if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) == (TF_RCVD_SCALE | TF_REQ_SCALE)) { tp->rcv_scale = tp->request_r_scale; } tp->rcv_adv += min(tp->rcv_wnd, TCP_MAXWIN << tp->rcv_scale); /* * If not all the data that was sent in the TFO SYN * has been acked, resend the remainder right away. */ if (IS_FASTOPEN(tp->t_flags) && (tp->snd_una != tp->snd_max)) { tp->snd_nxt = th->th_ack; tfo_partial = 1; } /* * If there's data, delay ACK; if there's also a FIN ACKNOW * will be turned on later. */ if (DELAY_ACK(tp, tlen) && tlen != 0 && (tfo_partial == 0)) { rack_timer_cancel(tp, (struct tcp_rack *)tp->t_fb_ptr, ((struct tcp_rack *)tp->t_fb_ptr)->r_ctl.rc_rcvtime, __LINE__); tp->t_flags |= TF_DELACK; } else { ((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output++; tp->t_flags |= TF_ACKNOW; } if (((thflags & (TH_CWR | TH_ECE)) == TH_ECE) && V_tcp_do_ecn) { tp->t_flags |= TF_ECN_PERMIT; TCPSTAT_INC(tcps_ecn_shs); } if (SEQ_GT(th->th_ack, tp->snd_una)) { /* * We advance snd_una for the * fast open case. If th_ack is * acknowledging data beyond * snd_una we can't just call * ack-processing since the * data stream in our send-map * will start at snd_una + 1 (one * beyond the SYN). If its just * equal we don't need to do that * and there is no send_map. */ tp->snd_una++; } /* * Received in SYN_SENT[*] state. Transitions: * SYN_SENT --> ESTABLISHED SYN_SENT* --> FIN_WAIT_1 */ tp->t_starttime = ticks; if (tp->t_flags & TF_NEEDFIN) { tcp_state_change(tp, TCPS_FIN_WAIT_1); tp->t_flags &= ~TF_NEEDFIN; thflags &= ~TH_SYN; } else { tcp_state_change(tp, TCPS_ESTABLISHED); TCP_PROBE5(connect__established, NULL, tp, mtod(m, const char *), tp, th); cc_conn_init(tp); } } else { /* * Received initial SYN in SYN-SENT[*] state => simultaneous * open. If segment contains CC option and there is a * cached CC, apply TAO test. If it succeeds, connection is * * half-synchronized. Otherwise, do 3-way handshake: * SYN-SENT -> SYN-RECEIVED SYN-SENT* -> SYN-RECEIVED* If * there was no CC option, clear cached CC value. */ tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN); tcp_state_change(tp, TCPS_SYN_RECEIVED); } INP_INFO_RLOCK_ASSERT(&V_tcbinfo); INP_WLOCK_ASSERT(tp->t_inpcb); /* * Advance th->th_seq to correspond to first data byte. If data, * trim to stay within window, dropping FIN if necessary. */ th->th_seq++; if (tlen > tp->rcv_wnd) { todrop = tlen - tp->rcv_wnd; m_adj(m, -todrop); tlen = tp->rcv_wnd; thflags &= ~TH_FIN; TCPSTAT_INC(tcps_rcvpackafterwin); TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop); } tp->snd_wl1 = th->th_seq - 1; tp->rcv_up = th->th_seq; /* * Client side of transaction: already sent SYN and data. If the * remote host used T/TCP to validate the SYN, our data will be * ACK'd; if so, enter normal data segment processing in the middle * of step 5, ack processing. Otherwise, goto step 6. */ if (thflags & TH_ACK) { if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) return (ret_val); /* We may have changed to FIN_WAIT_1 above */ if (tp->t_state == TCPS_FIN_WAIT_1) { /* * In FIN_WAIT_1 STATE in addition to the processing * for the ESTABLISHED state if our FIN is now * acknowledged then enter FIN_WAIT_2. */ if (ourfinisacked) { /* * If we can't receive any more data, then * closing user can proceed. Starting the * timer is contrary to the specification, * but if we don't get a FIN we'll hang * forever. * * XXXjl: we should release the tp also, and * use a compressed state. */ if (so->so_rcv.sb_state & SBS_CANTRCVMORE) { soisdisconnected(so); tcp_timer_activate(tp, TT_2MSL, (tcp_fast_finwait2_recycle ? tcp_finwait2_timeout : TP_MAXIDLE(tp))); } tcp_state_change(tp, TCPS_FIN_WAIT_2); } } } return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } /* * Return value of 1, the TCB is unlocked and most * likely gone, return value of 0, the TCP is still * locked. */ static int rack_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt) { int32_t ret_val = 0; int32_t ourfinisacked = 0; rack_calc_rwin(so, tp); if ((thflags & TH_ACK) && (SEQ_LEQ(th->th_ack, tp->snd_una) || SEQ_GT(th->th_ack, tp->snd_max))) { rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } if (IS_FASTOPEN(tp->t_flags)) { /* * When a TFO connection is in SYN_RECEIVED, the * only valid packets are the initial SYN, a * retransmit/copy of the initial SYN (possibly with * a subset of the original data), a valid ACK, a * FIN, or a RST. */ if ((thflags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) { rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } else if (thflags & TH_SYN) { /* non-initial SYN is ignored */ struct tcp_rack *rack; rack = (struct tcp_rack *)tp->t_fb_ptr; if ((rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT) || (rack->r_ctl.rc_hpts_flags & PACE_TMR_TLP) || (rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK)) { rack_do_drop(m, NULL); return (0); } } else if (!(thflags & (TH_ACK | TH_FIN | TH_RST))) { rack_do_drop(m, NULL); return (0); } } if (thflags & TH_RST) return (rack_process_rst(m, th, so, tp)); /* * RFC 1323 PAWS: If we have a timestamp reply on this segment and * it's less than ts_recent, drop it. */ if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent && TSTMP_LT(to->to_tsval, tp->ts_recent)) { if (rack_ts_check(m, th, tp, tlen, thflags, &ret_val)) return (ret_val); } /* * In the SYN-RECEIVED state, validate that the packet belongs to * this connection before trimming the data to fit the receive * window. Check the sequence number versus IRS since we know the * sequence numbers haven't wrapped. This is a partial fix for the * "LAND" DoS attack. */ if (SEQ_LT(th->th_seq, tp->irs)) { rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } if (rack_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) { return (ret_val); } /* * If last ACK falls within this segment's sequence numbers, record * its timestamp. NOTE: 1) That the test incorporates suggestions * from the latest proposal of the tcplw@cray.com list (Braden * 1993/04/26). 2) That updating only on newer timestamps interferes * with our earlier PAWS tests, so this check should be solely * predicated on the sequence space of this segment. 3) That we * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ * + SEG.Len instead of RFC1323's Last.ACK.Sent < SEG.SEQ + * SEG.Len, This modified check allows us to overcome RFC1323's * limitations as described in Stevens TCP/IP Illustrated Vol. 2 * p.869. In such cases, we can still calculate the RTT correctly * when RCV.NXT == Last.ACK.Sent. */ if ((to->to_flags & TOF_TS) != 0 && SEQ_LEQ(th->th_seq, tp->last_ack_sent) && SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + ((thflags & (TH_SYN | TH_FIN)) != 0))) { tp->ts_recent_age = tcp_ts_getticks(); tp->ts_recent = to->to_tsval; } tp->snd_wnd = tiwin; /* * If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN flag * is on (half-synchronized state), then queue data for later * processing; else drop segment and return. */ if ((thflags & TH_ACK) == 0) { if (IS_FASTOPEN(tp->t_flags)) { cc_conn_init(tp); } return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } TCPSTAT_INC(tcps_connects); soisconnected(so); /* Do window scaling? */ if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) == (TF_RCVD_SCALE | TF_REQ_SCALE)) { tp->rcv_scale = tp->request_r_scale; } /* * Make transitions: SYN-RECEIVED -> ESTABLISHED SYN-RECEIVED* -> * FIN-WAIT-1 */ tp->t_starttime = ticks; if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) { tcp_fastopen_decrement_counter(tp->t_tfo_pending); tp->t_tfo_pending = NULL; /* * Account for the ACK of our SYN prior to * regular ACK processing below. */ tp->snd_una++; } if (tp->t_flags & TF_NEEDFIN) { tcp_state_change(tp, TCPS_FIN_WAIT_1); tp->t_flags &= ~TF_NEEDFIN; } else { tcp_state_change(tp, TCPS_ESTABLISHED); TCP_PROBE5(accept__established, NULL, tp, mtod(m, const char *), tp, th); /* * TFO connections call cc_conn_init() during SYN * processing. Calling it again here for such connections * is not harmless as it would undo the snd_cwnd reduction * that occurs when a TFO SYN|ACK is retransmitted. */ if (!IS_FASTOPEN(tp->t_flags)) cc_conn_init(tp); } /* * If segment contains data or ACK, will call tcp_reass() later; if * not, do so now to pass queued data to user. */ if (tlen == 0 && (thflags & TH_FIN) == 0) (void) tcp_reass(tp, (struct tcphdr *)0, NULL, 0, (struct mbuf *)0); tp->snd_wl1 = th->th_seq - 1; if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) { return (ret_val); } if (tp->t_state == TCPS_FIN_WAIT_1) { /* We could have went to FIN_WAIT_1 (or EST) above */ /* * In FIN_WAIT_1 STATE in addition to the processing for the * ESTABLISHED state if our FIN is now acknowledged then * enter FIN_WAIT_2. */ if (ourfinisacked) { /* * If we can't receive any more data, then closing * user can proceed. Starting the timer is contrary * to the specification, but if we don't get a FIN * we'll hang forever. * * XXXjl: we should release the tp also, and use a * compressed state. */ if (so->so_rcv.sb_state & SBS_CANTRCVMORE) { soisdisconnected(so); tcp_timer_activate(tp, TT_2MSL, (tcp_fast_finwait2_recycle ? tcp_finwait2_timeout : TP_MAXIDLE(tp))); } tcp_state_change(tp, TCPS_FIN_WAIT_2); } } return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } /* * Return value of 1, the TCB is unlocked and most * likely gone, return value of 0, the TCP is still * locked. */ static int rack_do_established(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt) { int32_t ret_val = 0; /* * Header prediction: check for the two common cases of a * uni-directional data xfer. If the packet has no control flags, * is in-sequence, the window didn't change and we're not * retransmitting, it's a candidate. If the length is zero and the * ack moved forward, we're the sender side of the xfer. Just free * the data acked & wake any higher level process that was blocked * waiting for space. If the length is non-zero and the ack didn't * move, we're the receiver side. If we're getting packets in-order * (the reassembly queue is empty), add the data toc The socket * buffer and note that we need a delayed ack. Make sure that the * hidden state-flags are also off. Since we check for * TCPS_ESTABLISHED first, it can only be TH_NEEDSYN. */ if (__predict_true(((to->to_flags & TOF_SACK) == 0)) && __predict_true((thflags & (TH_SYN | TH_FIN | TH_RST | TH_URG | TH_ACK)) == TH_ACK) && __predict_true(SEGQ_EMPTY(tp)) && __predict_true(th->th_seq == tp->rcv_nxt)) { struct tcp_rack *rack; rack = (struct tcp_rack *)tp->t_fb_ptr; if (tlen == 0) { if (rack_fastack(m, th, so, tp, to, drop_hdrlen, tlen, tiwin, nxt_pkt, rack->r_ctl.rc_rcvtime)) { return (0); } } else { if (rack_do_fastnewdata(m, th, so, tp, to, drop_hdrlen, tlen, tiwin, nxt_pkt)) { return (0); } } } rack_calc_rwin(so, tp); if (thflags & TH_RST) return (rack_process_rst(m, th, so, tp)); /* * RFC5961 Section 4.2 Send challenge ACK for any SYN in * synchronized state. */ if (thflags & TH_SYN) { rack_challenge_ack(m, th, tp, &ret_val); return (ret_val); } /* * RFC 1323 PAWS: If we have a timestamp reply on this segment and * it's less than ts_recent, drop it. */ if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent && TSTMP_LT(to->to_tsval, tp->ts_recent)) { if (rack_ts_check(m, th, tp, tlen, thflags, &ret_val)) return (ret_val); } if (rack_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) { return (ret_val); } /* * If last ACK falls within this segment's sequence numbers, record * its timestamp. NOTE: 1) That the test incorporates suggestions * from the latest proposal of the tcplw@cray.com list (Braden * 1993/04/26). 2) That updating only on newer timestamps interferes * with our earlier PAWS tests, so this check should be solely * predicated on the sequence space of this segment. 3) That we * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ * + SEG.Len instead of RFC1323's Last.ACK.Sent < SEG.SEQ + * SEG.Len, This modified check allows us to overcome RFC1323's * limitations as described in Stevens TCP/IP Illustrated Vol. 2 * p.869. In such cases, we can still calculate the RTT correctly * when RCV.NXT == Last.ACK.Sent. */ if ((to->to_flags & TOF_TS) != 0 && SEQ_LEQ(th->th_seq, tp->last_ack_sent) && SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + ((thflags & (TH_SYN | TH_FIN)) != 0))) { tp->ts_recent_age = tcp_ts_getticks(); tp->ts_recent = to->to_tsval; } /* * If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN flag * is on (half-synchronized state), then queue data for later * processing; else drop segment and return. */ if ((thflags & TH_ACK) == 0) { if (tp->t_flags & TF_NEEDSYN) { return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } else if (tp->t_flags & TF_ACKNOW) { rack_do_dropafterack(m, tp, th, thflags, tlen, &ret_val); return (ret_val); } else { rack_do_drop(m, NULL); return (0); } } /* * Ack processing. */ if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) { return (ret_val); } if (sbavail(&so->so_snd)) { if (rack_progress_timeout_check(tp)) { tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT); rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } } /* State changes only happen in rack_process_data() */ return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } /* * Return value of 1, the TCB is unlocked and most * likely gone, return value of 0, the TCP is still * locked. */ static int rack_do_close_wait(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt) { int32_t ret_val = 0; rack_calc_rwin(so, tp); if (thflags & TH_RST) return (rack_process_rst(m, th, so, tp)); /* * RFC5961 Section 4.2 Send challenge ACK for any SYN in * synchronized state. */ if (thflags & TH_SYN) { rack_challenge_ack(m, th, tp, &ret_val); return (ret_val); } /* * RFC 1323 PAWS: If we have a timestamp reply on this segment and * it's less than ts_recent, drop it. */ if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent && TSTMP_LT(to->to_tsval, tp->ts_recent)) { if (rack_ts_check(m, th, tp, tlen, thflags, &ret_val)) return (ret_val); } if (rack_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) { return (ret_val); } /* * If last ACK falls within this segment's sequence numbers, record * its timestamp. NOTE: 1) That the test incorporates suggestions * from the latest proposal of the tcplw@cray.com list (Braden * 1993/04/26). 2) That updating only on newer timestamps interferes * with our earlier PAWS tests, so this check should be solely * predicated on the sequence space of this segment. 3) That we * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ * + SEG.Len instead of RFC1323's Last.ACK.Sent < SEG.SEQ + * SEG.Len, This modified check allows us to overcome RFC1323's * limitations as described in Stevens TCP/IP Illustrated Vol. 2 * p.869. In such cases, we can still calculate the RTT correctly * when RCV.NXT == Last.ACK.Sent. */ if ((to->to_flags & TOF_TS) != 0 && SEQ_LEQ(th->th_seq, tp->last_ack_sent) && SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + ((thflags & (TH_SYN | TH_FIN)) != 0))) { tp->ts_recent_age = tcp_ts_getticks(); tp->ts_recent = to->to_tsval; } /* * If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN flag * is on (half-synchronized state), then queue data for later * processing; else drop segment and return. */ if ((thflags & TH_ACK) == 0) { if (tp->t_flags & TF_NEEDSYN) { return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } else if (tp->t_flags & TF_ACKNOW) { rack_do_dropafterack(m, tp, th, thflags, tlen, &ret_val); return (ret_val); } else { rack_do_drop(m, NULL); return (0); } } /* * Ack processing. */ if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) { return (ret_val); } if (sbavail(&so->so_snd)) { if (rack_progress_timeout_check(tp)) { tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT); rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } } return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } static int rack_check_data_after_close(struct mbuf *m, struct tcpcb *tp, int32_t *tlen, struct tcphdr *th, struct socket *so) { struct tcp_rack *rack; INP_INFO_RLOCK_ASSERT(&V_tcbinfo); rack = (struct tcp_rack *)tp->t_fb_ptr; if (rack->rc_allow_data_af_clo == 0) { close_now: tp = tcp_close(tp); TCPSTAT_INC(tcps_rcvafterclose); rack_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, (*tlen)); return (1); } if (sbavail(&so->so_snd) == 0) goto close_now; /* Ok we allow data that is ignored and a followup reset */ tp->rcv_nxt = th->th_seq + *tlen; tp->t_flags2 |= TF2_DROP_AF_DATA; rack->r_wanted_output = 1; *tlen = 0; return (0); } /* * Return value of 1, the TCB is unlocked and most * likely gone, return value of 0, the TCP is still * locked. */ static int rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt) { int32_t ret_val = 0; int32_t ourfinisacked = 0; rack_calc_rwin(so, tp); if (thflags & TH_RST) return (rack_process_rst(m, th, so, tp)); /* * RFC5961 Section 4.2 Send challenge ACK for any SYN in * synchronized state. */ if (thflags & TH_SYN) { rack_challenge_ack(m, th, tp, &ret_val); return (ret_val); } /* * RFC 1323 PAWS: If we have a timestamp reply on this segment and * it's less than ts_recent, drop it. */ if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent && TSTMP_LT(to->to_tsval, tp->ts_recent)) { if (rack_ts_check(m, th, tp, tlen, thflags, &ret_val)) return (ret_val); } if (rack_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) { return (ret_val); } /* * If new data are received on a connection after the user processes * are gone, then RST the other end. */ if ((so->so_state & SS_NOFDREF) && tlen) { if (rack_check_data_after_close(m, tp, &tlen, th, so)) return (1); } /* * If last ACK falls within this segment's sequence numbers, record * its timestamp. NOTE: 1) That the test incorporates suggestions * from the latest proposal of the tcplw@cray.com list (Braden * 1993/04/26). 2) That updating only on newer timestamps interferes * with our earlier PAWS tests, so this check should be solely * predicated on the sequence space of this segment. 3) That we * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ * + SEG.Len instead of RFC1323's Last.ACK.Sent < SEG.SEQ + * SEG.Len, This modified check allows us to overcome RFC1323's * limitations as described in Stevens TCP/IP Illustrated Vol. 2 * p.869. In such cases, we can still calculate the RTT correctly * when RCV.NXT == Last.ACK.Sent. */ if ((to->to_flags & TOF_TS) != 0 && SEQ_LEQ(th->th_seq, tp->last_ack_sent) && SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + ((thflags & (TH_SYN | TH_FIN)) != 0))) { tp->ts_recent_age = tcp_ts_getticks(); tp->ts_recent = to->to_tsval; } /* * If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN flag * is on (half-synchronized state), then queue data for later * processing; else drop segment and return. */ if ((thflags & TH_ACK) == 0) { if (tp->t_flags & TF_NEEDSYN) { return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } else if (tp->t_flags & TF_ACKNOW) { rack_do_dropafterack(m, tp, th, thflags, tlen, &ret_val); return (ret_val); } else { rack_do_drop(m, NULL); return (0); } } /* * Ack processing. */ if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) { return (ret_val); } if (ourfinisacked) { /* * If we can't receive any more data, then closing user can * proceed. Starting the timer is contrary to the * specification, but if we don't get a FIN we'll hang * forever. * * XXXjl: we should release the tp also, and use a * compressed state. */ if (so->so_rcv.sb_state & SBS_CANTRCVMORE) { soisdisconnected(so); tcp_timer_activate(tp, TT_2MSL, (tcp_fast_finwait2_recycle ? tcp_finwait2_timeout : TP_MAXIDLE(tp))); } tcp_state_change(tp, TCPS_FIN_WAIT_2); } if (sbavail(&so->so_snd)) { if (rack_progress_timeout_check(tp)) { tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT); rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } } return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } /* * Return value of 1, the TCB is unlocked and most * likely gone, return value of 0, the TCP is still * locked. */ static int rack_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt) { int32_t ret_val = 0; int32_t ourfinisacked = 0; rack_calc_rwin(so, tp); if (thflags & TH_RST) return (rack_process_rst(m, th, so, tp)); /* * RFC5961 Section 4.2 Send challenge ACK for any SYN in * synchronized state. */ if (thflags & TH_SYN) { rack_challenge_ack(m, th, tp, &ret_val); return (ret_val); } /* * RFC 1323 PAWS: If we have a timestamp reply on this segment and * it's less than ts_recent, drop it. */ if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent && TSTMP_LT(to->to_tsval, tp->ts_recent)) { if (rack_ts_check(m, th, tp, tlen, thflags, &ret_val)) return (ret_val); } if (rack_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) { return (ret_val); } /* * If new data are received on a connection after the user processes * are gone, then RST the other end. */ if ((so->so_state & SS_NOFDREF) && tlen) { if (rack_check_data_after_close(m, tp, &tlen, th, so)) return (1); } /* * If last ACK falls within this segment's sequence numbers, record * its timestamp. NOTE: 1) That the test incorporates suggestions * from the latest proposal of the tcplw@cray.com list (Braden * 1993/04/26). 2) That updating only on newer timestamps interferes * with our earlier PAWS tests, so this check should be solely * predicated on the sequence space of this segment. 3) That we * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ * + SEG.Len instead of RFC1323's Last.ACK.Sent < SEG.SEQ + * SEG.Len, This modified check allows us to overcome RFC1323's * limitations as described in Stevens TCP/IP Illustrated Vol. 2 * p.869. In such cases, we can still calculate the RTT correctly * when RCV.NXT == Last.ACK.Sent. */ if ((to->to_flags & TOF_TS) != 0 && SEQ_LEQ(th->th_seq, tp->last_ack_sent) && SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + ((thflags & (TH_SYN | TH_FIN)) != 0))) { tp->ts_recent_age = tcp_ts_getticks(); tp->ts_recent = to->to_tsval; } /* * If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN flag * is on (half-synchronized state), then queue data for later * processing; else drop segment and return. */ if ((thflags & TH_ACK) == 0) { if (tp->t_flags & TF_NEEDSYN) { return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } else if (tp->t_flags & TF_ACKNOW) { rack_do_dropafterack(m, tp, th, thflags, tlen, &ret_val); return (ret_val); } else { rack_do_drop(m, NULL); return (0); } } /* * Ack processing. */ if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) { return (ret_val); } if (ourfinisacked) { INP_INFO_RLOCK_ASSERT(&V_tcbinfo); tcp_twstart(tp); m_freem(m); return (1); } if (sbavail(&so->so_snd)) { if (rack_progress_timeout_check(tp)) { tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT); rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } } return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } /* * Return value of 1, the TCB is unlocked and most * likely gone, return value of 0, the TCP is still * locked. */ static int rack_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt) { int32_t ret_val = 0; int32_t ourfinisacked = 0; rack_calc_rwin(so, tp); if (thflags & TH_RST) return (rack_process_rst(m, th, so, tp)); /* * RFC5961 Section 4.2 Send challenge ACK for any SYN in * synchronized state. */ if (thflags & TH_SYN) { rack_challenge_ack(m, th, tp, &ret_val); return (ret_val); } /* * RFC 1323 PAWS: If we have a timestamp reply on this segment and * it's less than ts_recent, drop it. */ if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent && TSTMP_LT(to->to_tsval, tp->ts_recent)) { if (rack_ts_check(m, th, tp, tlen, thflags, &ret_val)) return (ret_val); } if (rack_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) { return (ret_val); } /* * If new data are received on a connection after the user processes * are gone, then RST the other end. */ if ((so->so_state & SS_NOFDREF) && tlen) { if (rack_check_data_after_close(m, tp, &tlen, th, so)) return (1); } /* * If last ACK falls within this segment's sequence numbers, record * its timestamp. NOTE: 1) That the test incorporates suggestions * from the latest proposal of the tcplw@cray.com list (Braden * 1993/04/26). 2) That updating only on newer timestamps interferes * with our earlier PAWS tests, so this check should be solely * predicated on the sequence space of this segment. 3) That we * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ * + SEG.Len instead of RFC1323's Last.ACK.Sent < SEG.SEQ + * SEG.Len, This modified check allows us to overcome RFC1323's * limitations as described in Stevens TCP/IP Illustrated Vol. 2 * p.869. In such cases, we can still calculate the RTT correctly * when RCV.NXT == Last.ACK.Sent. */ if ((to->to_flags & TOF_TS) != 0 && SEQ_LEQ(th->th_seq, tp->last_ack_sent) && SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + ((thflags & (TH_SYN | TH_FIN)) != 0))) { tp->ts_recent_age = tcp_ts_getticks(); tp->ts_recent = to->to_tsval; } /* * If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN flag * is on (half-synchronized state), then queue data for later * processing; else drop segment and return. */ if ((thflags & TH_ACK) == 0) { if (tp->t_flags & TF_NEEDSYN) { return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } else if (tp->t_flags & TF_ACKNOW) { rack_do_dropafterack(m, tp, th, thflags, tlen, &ret_val); return (ret_val); } else { rack_do_drop(m, NULL); return (0); } } /* * case TCPS_LAST_ACK: Ack processing. */ if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) { return (ret_val); } if (ourfinisacked) { INP_INFO_RLOCK_ASSERT(&V_tcbinfo); tp = tcp_close(tp); rack_do_drop(m, tp); return (1); } if (sbavail(&so->so_snd)) { if (rack_progress_timeout_check(tp)) { tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT); rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } } return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } /* * Return value of 1, the TCB is unlocked and most * likely gone, return value of 0, the TCP is still * locked. */ static int rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt) { int32_t ret_val = 0; int32_t ourfinisacked = 0; rack_calc_rwin(so, tp); /* Reset receive buffer auto scaling when not in bulk receive mode. */ if (thflags & TH_RST) return (rack_process_rst(m, th, so, tp)); /* * RFC5961 Section 4.2 Send challenge ACK for any SYN in * synchronized state. */ if (thflags & TH_SYN) { rack_challenge_ack(m, th, tp, &ret_val); return (ret_val); } /* * RFC 1323 PAWS: If we have a timestamp reply on this segment and * it's less than ts_recent, drop it. */ if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent && TSTMP_LT(to->to_tsval, tp->ts_recent)) { if (rack_ts_check(m, th, tp, tlen, thflags, &ret_val)) return (ret_val); } if (rack_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) { return (ret_val); } /* * If new data are received on a connection after the user processes * are gone, then RST the other end. */ if ((so->so_state & SS_NOFDREF) && tlen) { if (rack_check_data_after_close(m, tp, &tlen, th, so)) return (1); } /* * If last ACK falls within this segment's sequence numbers, record * its timestamp. NOTE: 1) That the test incorporates suggestions * from the latest proposal of the tcplw@cray.com list (Braden * 1993/04/26). 2) That updating only on newer timestamps interferes * with our earlier PAWS tests, so this check should be solely * predicated on the sequence space of this segment. 3) That we * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ * + SEG.Len instead of RFC1323's Last.ACK.Sent < SEG.SEQ + * SEG.Len, This modified check allows us to overcome RFC1323's * limitations as described in Stevens TCP/IP Illustrated Vol. 2 * p.869. In such cases, we can still calculate the RTT correctly * when RCV.NXT == Last.ACK.Sent. */ if ((to->to_flags & TOF_TS) != 0 && SEQ_LEQ(th->th_seq, tp->last_ack_sent) && SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + ((thflags & (TH_SYN | TH_FIN)) != 0))) { tp->ts_recent_age = tcp_ts_getticks(); tp->ts_recent = to->to_tsval; } /* * If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN flag * is on (half-synchronized state), then queue data for later * processing; else drop segment and return. */ if ((thflags & TH_ACK) == 0) { if (tp->t_flags & TF_NEEDSYN) { return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } else if (tp->t_flags & TF_ACKNOW) { rack_do_dropafterack(m, tp, th, thflags, tlen, &ret_val); return (ret_val); } else { rack_do_drop(m, NULL); return (0); } } /* * Ack processing. */ if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) { return (ret_val); } if (sbavail(&so->so_snd)) { if (rack_progress_timeout_check(tp)) { tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT); rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return (1); } } return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt)); } static void inline rack_clear_rate_sample(struct tcp_rack *rack) { rack->r_ctl.rack_rs.rs_flags = RACK_RTT_EMPTY; rack->r_ctl.rack_rs.rs_rtt_cnt = 0; rack->r_ctl.rack_rs.rs_rtt_tot = 0; } static int rack_init(struct tcpcb *tp) { struct tcp_rack *rack = NULL; tp->t_fb_ptr = uma_zalloc(rack_pcb_zone, M_NOWAIT); if (tp->t_fb_ptr == NULL) { /* * We need to allocate memory but cant. The INP and INP_INFO * locks and they are recusive (happens during setup. So a * scheme to drop the locks fails :( * */ return (ENOMEM); } memset(tp->t_fb_ptr, 0, sizeof(struct tcp_rack)); rack = (struct tcp_rack *)tp->t_fb_ptr; TAILQ_INIT(&rack->r_ctl.rc_map); TAILQ_INIT(&rack->r_ctl.rc_free); TAILQ_INIT(&rack->r_ctl.rc_tmap); rack->rc_tp = tp; if (tp->t_inpcb) { rack->rc_inp = tp->t_inpcb; } /* Probably not needed but lets be sure */ rack_clear_rate_sample(rack); rack->r_cpu = 0; rack->r_ctl.rc_reorder_fade = rack_reorder_fade; rack->rc_allow_data_af_clo = rack_ignore_data_after_close; rack->r_ctl.rc_tlp_threshold = rack_tlp_thresh; rack->rc_pace_reduce = rack_slot_reduction; if (V_tcp_delack_enabled) tp->t_delayed_ack = 1; else tp->t_delayed_ack = 0; rack->rc_pace_max_segs = rack_hptsi_segments; rack->r_ctl.rc_early_recovery_segs = rack_early_recovery_max_seg; rack->r_ctl.rc_reorder_shift = rack_reorder_thresh; rack->r_ctl.rc_pkt_delay = rack_pkt_delay; rack->r_ctl.rc_prop_reduce = rack_use_proportional_reduce; rack->r_idle_reduce_largest = rack_reduce_largest_on_idle; rack->r_enforce_min_pace = rack_min_pace_time; rack->r_min_pace_seg_thresh = rack_min_pace_time_seg_req; rack->r_ctl.rc_prop_rate = rack_proportional_rate; rack->r_ctl.rc_tlp_cwnd_reduce = rack_lower_cwnd_at_tlp; rack->r_ctl.rc_early_recovery = rack_early_recovery; rack->rc_always_pace = rack_pace_every_seg; rack->r_ctl.rc_rate_sample_method = rack_rate_sample_method; rack->rack_tlp_threshold_use = rack_tlp_threshold_use; rack->r_ctl.rc_prr_sendalot = rack_send_a_lot_in_prr; rack->r_ctl.rc_min_to = rack_min_to; rack->r_ctl.rc_prr_inc_var = rack_inc_var; rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), __LINE__, 0, 0, 0); if (tp->snd_una != tp->snd_max) { /* Create a send map for the current outstanding data */ struct rack_sendmap *rsm; rsm = rack_alloc(rack); if (rsm == NULL) { uma_zfree(rack_pcb_zone, tp->t_fb_ptr); tp->t_fb_ptr = NULL; return (ENOMEM); } rsm->r_flags = RACK_OVERMAX; rsm->r_tim_lastsent[0] = tcp_ts_getticks(); rsm->r_rtr_cnt = 1; rsm->r_rtr_bytes = 0; rsm->r_start = tp->snd_una; rsm->r_end = tp->snd_max; rsm->r_sndcnt = 0; TAILQ_INSERT_TAIL(&rack->r_ctl.rc_map, rsm, r_next); TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext); rsm->r_in_tmap = 1; } return (0); } static int rack_handoff_ok(struct tcpcb *tp) { if ((tp->t_state == TCPS_CLOSED) || (tp->t_state == TCPS_LISTEN)) { /* Sure no problem though it may not stick */ return (0); } if ((tp->t_state == TCPS_SYN_SENT) || (tp->t_state == TCPS_SYN_RECEIVED)) { /* * We really don't know you have to get to ESTAB or beyond * to tell. */ return (EAGAIN); } if (tp->t_flags & TF_SACK_PERMIT) { return (0); } /* * If we reach here we don't do SACK on this connection so we can * never do rack. */ return (EINVAL); } static void rack_fini(struct tcpcb *tp, int32_t tcb_is_purged) { if (tp->t_fb_ptr) { struct tcp_rack *rack; struct rack_sendmap *rsm; rack = (struct tcp_rack *)tp->t_fb_ptr; #ifdef TCP_BLACKBOX tcp_log_flowend(tp); #endif rsm = TAILQ_FIRST(&rack->r_ctl.rc_map); while (rsm) { TAILQ_REMOVE(&rack->r_ctl.rc_map, rsm, r_next); uma_zfree(rack_zone, rsm); rsm = TAILQ_FIRST(&rack->r_ctl.rc_map); } rsm = TAILQ_FIRST(&rack->r_ctl.rc_free); while (rsm) { TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_next); uma_zfree(rack_zone, rsm); rsm = TAILQ_FIRST(&rack->r_ctl.rc_free); } rack->rc_free_cnt = 0; uma_zfree(rack_pcb_zone, tp->t_fb_ptr); tp->t_fb_ptr = NULL; } } static void rack_set_state(struct tcpcb *tp, struct tcp_rack *rack) { switch (tp->t_state) { case TCPS_SYN_SENT: rack->r_state = TCPS_SYN_SENT; rack->r_substate = rack_do_syn_sent; break; case TCPS_SYN_RECEIVED: rack->r_state = TCPS_SYN_RECEIVED; rack->r_substate = rack_do_syn_recv; break; case TCPS_ESTABLISHED: rack->r_state = TCPS_ESTABLISHED; rack->r_substate = rack_do_established; break; case TCPS_CLOSE_WAIT: rack->r_state = TCPS_CLOSE_WAIT; rack->r_substate = rack_do_close_wait; break; case TCPS_FIN_WAIT_1: rack->r_state = TCPS_FIN_WAIT_1; rack->r_substate = rack_do_fin_wait_1; break; case TCPS_CLOSING: rack->r_state = TCPS_CLOSING; rack->r_substate = rack_do_closing; break; case TCPS_LAST_ACK: rack->r_state = TCPS_LAST_ACK; rack->r_substate = rack_do_lastack; break; case TCPS_FIN_WAIT_2: rack->r_state = TCPS_FIN_WAIT_2; rack->r_substate = rack_do_fin_wait_2; break; case TCPS_LISTEN: case TCPS_CLOSED: case TCPS_TIME_WAIT: default: #ifdef INVARIANTS panic("tcp tp:%p state:%d sees impossible state?", tp, tp->t_state); #endif break; }; } static void rack_timer_audit(struct tcpcb *tp, struct tcp_rack *rack, struct sockbuf *sb) { /* * We received an ack, and then did not * call send or were bounced out due to the * hpts was running. Now a timer is up as well, is * it the right timer? */ struct rack_sendmap *rsm; int tmr_up; tmr_up = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK; if (rack->rc_in_persist && (tmr_up == PACE_TMR_PERSIT)) return; rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap); if (((rsm == NULL) || (tp->t_state < TCPS_ESTABLISHED)) && (tmr_up == PACE_TMR_RXT)) { /* Should be an RXT */ return; } if (rsm == NULL) { /* Nothing outstanding? */ if (tp->t_flags & TF_DELACK) { if (tmr_up == PACE_TMR_DELACK) /* We are supposed to have delayed ack up and we do */ return; } else if (sbavail(&tp->t_inpcb->inp_socket->so_snd) && (tmr_up == PACE_TMR_RXT)) { /* * if we hit enobufs then we would expect the possiblity * of nothing outstanding and the RXT up (and the hptsi timer). */ return; } else if (((tcp_always_keepalive || rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) && (tp->t_state <= TCPS_CLOSING)) && (tmr_up == PACE_TMR_KEEP) && (tp->snd_max == tp->snd_una)) { /* We should have keep alive up and we do */ return; } } if (rsm && (rsm->r_flags & RACK_SACK_PASSED)) { if ((tp->t_flags & TF_SENTFIN) && ((tp->snd_max - tp->snd_una) == 1) && (rsm->r_flags & RACK_HAS_FIN)) { /* needs to be a RXT */ if (tmr_up == PACE_TMR_RXT) return; } else if (tmr_up == PACE_TMR_RACK) return; } else if (SEQ_GT(tp->snd_max,tp->snd_una) && ((tmr_up == PACE_TMR_TLP) || (tmr_up == PACE_TMR_RXT))) { /* * Either a TLP or RXT is fine if no sack-passed * is in place and data is outstanding. */ return; } else if (tmr_up == PACE_TMR_DELACK) { /* * If the delayed ack was going to go off * before the rtx/tlp/rack timer were going to * expire, then that would be the timer in control. * Note we don't check the time here trusting the * code is correct. */ return; } /* * Ok the timer originally started is not what we want now. * We will force the hpts to be stopped if any, and restart * with the slot set to what was in the saved slot. */ rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__); rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), __LINE__, 0, 0, 0); } static void rack_hpts_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos, int32_t nxt_pkt, struct timeval *tv) { int32_t thflags, retval, did_out = 0; int32_t way_out = 0; uint32_t cts; uint32_t tiwin; struct tcpopt to; struct tcp_rack *rack; struct rack_sendmap *rsm; int32_t prev_state = 0; cts = tcp_tv_to_mssectick(tv); rack = (struct tcp_rack *)tp->t_fb_ptr; kern_prefetch(rack, &prev_state); prev_state = 0; thflags = th->th_flags; /* * If this is either a state-changing packet or current state isn't * established, we require a read lock on tcbinfo. Otherwise, we * allow the tcbinfo to be in either locked or unlocked, as the * caller may have unnecessarily acquired a lock due to a race. */ if ((thflags & (TH_SYN | TH_FIN | TH_RST)) != 0 || tp->t_state != TCPS_ESTABLISHED) { INP_INFO_RLOCK_ASSERT(&V_tcbinfo); } INP_WLOCK_ASSERT(tp->t_inpcb); KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN", __func__)); KASSERT(tp->t_state != TCPS_TIME_WAIT, ("%s: TCPS_TIME_WAIT", __func__)); { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts; log.u_bbr.ininput = rack->rc_inp->inp_in_input; TCP_LOG_EVENT(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_IN, 0, tlen, &log, true); } if ((thflags & TH_SYN) && (thflags & TH_FIN) && V_drop_synfin) { way_out = 4; goto done_with_input; } /* * If a segment with the ACK-bit set arrives in the SYN-SENT state * check SEQ.ACK first as described on page 66 of RFC 793, section 3.9. */ if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) && (SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) { rack_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen); return; } /* * Segment received on connection. Reset idle time and keep-alive * timer. XXX: This should be done after segment validation to * ignore broken/spoofed segs. */ if (tp->t_idle_reduce && (tp->snd_max == tp->snd_una)) { #ifdef NETFLIX_CWV if ((tp->cwv_enabled) && ((tp->cwv_cwnd_valid == 0) && TCPS_HAVEESTABLISHED(tp->t_state) && (tp->snd_cwnd > tp->snd_cwv.init_cwnd))) { tcp_newcwv_nvp_closedown(tp); } else #endif if ((ticks - tp->t_rcvtime) >= tp->t_rxtcur) { counter_u64_add(rack_input_idle_reduces, 1); rack_cc_after_idle(tp, (rack->r_idle_reduce_largest ? 1 :0)); } } rack->r_ctl.rc_rcvtime = cts; tp->t_rcvtime = ticks; #ifdef NETFLIX_CWV if (tp->cwv_enabled) { if ((tp->cwv_cwnd_valid == 0) && TCPS_HAVEESTABLISHED(tp->t_state) && (tp->snd_cwnd > tp->snd_cwv.init_cwnd)) tcp_newcwv_nvp_closedown(tp); } #endif /* * Unscale the window into a 32-bit value. For the SYN_SENT state * the scale is zero. */ tiwin = th->th_win << tp->snd_scale; #ifdef NETFLIX_STATS stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_FRWIN, tiwin); #endif /* * TCP ECN processing. XXXJTL: If we ever use ECN, we need to move * this to occur after we've validated the segment. */ if (tp->t_flags & TF_ECN_PERMIT) { if (thflags & TH_CWR) tp->t_flags &= ~TF_ECN_SND_ECE; switch (iptos & IPTOS_ECN_MASK) { case IPTOS_ECN_CE: tp->t_flags |= TF_ECN_SND_ECE; TCPSTAT_INC(tcps_ecn_ce); break; case IPTOS_ECN_ECT0: TCPSTAT_INC(tcps_ecn_ect0); break; case IPTOS_ECN_ECT1: TCPSTAT_INC(tcps_ecn_ect1); break; } /* Congestion experienced. */ if (thflags & TH_ECE) { rack_cong_signal(tp, th, CC_ECN); } } /* * Parse options on any incoming segment. */ tcp_dooptions(&to, (u_char *)(th + 1), (th->th_off << 2) - sizeof(struct tcphdr), (thflags & TH_SYN) ? TO_SYN : 0); /* * If echoed timestamp is later than the current time, fall back to * non RFC1323 RTT calculation. Normalize timestamp if syncookies * were used when this connection was established. */ if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) { to.to_tsecr -= tp->ts_offset; if (TSTMP_GT(to.to_tsecr, cts)) to.to_tsecr = 0; } /* * If its the first time in we need to take care of options and * verify we can do SACK for rack! */ if (rack->r_state == 0) { /* Should be init'd by rack_init() */ KASSERT(rack->rc_inp != NULL, ("%s: rack->rc_inp unexpectedly NULL", __func__)); if (rack->rc_inp == NULL) { rack->rc_inp = tp->t_inpcb; } /* * Process options only when we get SYN/ACK back. The SYN * case for incoming connections is handled in tcp_syncache. * According to RFC1323 the window field in a SYN (i.e., a * or ) segment itself is never scaled. XXX * this is traditional behavior, may need to be cleaned up. */ rack->r_cpu = inp_to_cpuid(tp->t_inpcb); if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) { if ((to.to_flags & TOF_SCALE) && (tp->t_flags & TF_REQ_SCALE)) { tp->t_flags |= TF_RCVD_SCALE; tp->snd_scale = to.to_wscale; } /* * Initial send window. It will be updated with the * next incoming segment to the scaled value. */ tp->snd_wnd = th->th_win; if (to.to_flags & TOF_TS) { tp->t_flags |= TF_RCVD_TSTMP; tp->ts_recent = to.to_tsval; tp->ts_recent_age = cts; } if (to.to_flags & TOF_MSS) tcp_mss(tp, to.to_mss); if ((tp->t_flags & TF_SACK_PERMIT) && (to.to_flags & TOF_SACKPERM) == 0) tp->t_flags &= ~TF_SACK_PERMIT; if (IS_FASTOPEN(tp->t_flags)) { if (to.to_flags & TOF_FASTOPEN) { uint16_t mss; if (to.to_flags & TOF_MSS) mss = to.to_mss; else if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) mss = TCP6_MSS; else mss = TCP_MSS; tcp_fastopen_update_cache(tp, mss, to.to_tfo_len, to.to_tfo_cookie); } else tcp_fastopen_disable_path(tp); } } /* * At this point we are at the initial call. Here we decide * if we are doing RACK or not. We do this by seeing if * TF_SACK_PERMIT is set, if not rack is *not* possible and * we switch to the default code. */ if ((tp->t_flags & TF_SACK_PERMIT) == 0) { tcp_switch_back_to_default(tp); (*tp->t_fb->tfb_tcp_do_segment) (m, th, so, tp, drop_hdrlen, tlen, iptos); return; } /* Set the flag */ rack->r_is_v6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; tcp_set_hpts(tp->t_inpcb); rack_stop_all_timers(tp); sack_filter_clear(&rack->r_ctl.rack_sf, th->th_ack); } /* * This is the one exception case where we set the rack state * always. All other times (timers etc) we must have a rack-state * set (so we assure we have done the checks above for SACK). */ if (rack->r_state != tp->t_state) rack_set_state(tp, rack); if (SEQ_GT(th->th_ack, tp->snd_una) && (rsm = TAILQ_FIRST(&rack->r_ctl.rc_map)) != NULL) kern_prefetch(rsm, &prev_state); prev_state = rack->r_state; rack->r_ctl.rc_tlp_send_cnt = 0; rack_clear_rate_sample(rack); retval = (*rack->r_substate) (m, th, so, tp, &to, drop_hdrlen, tlen, tiwin, thflags, nxt_pkt); #ifdef INVARIANTS if ((retval == 0) && (tp->t_inpcb == NULL)) { panic("retval:%d tp:%p t_inpcb:NULL state:%d", retval, tp, prev_state); } #endif if (retval == 0) { /* * If retval is 1 the tcb is unlocked and most likely the tp * is gone. */ INP_WLOCK_ASSERT(tp->t_inpcb); tcp_rack_xmit_timer_commit(rack, tp); if (((tp->snd_max - tp->snd_una) > tp->snd_wnd) && (rack->rc_in_persist == 0)){ /* * The peer shrunk its window on us to the point * where we have sent too much. The only thing * we can do here is stop any timers and * enter persist. We most likely lost the last * bytes we sent but oh well, we will have to * retransmit them after the peer is caught up. */ if (rack->rc_inp->inp_in_hpts) tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT); rack_timer_cancel(tp, rack, cts, __LINE__); rack_enter_persist(tp, rack, cts); rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), __LINE__, 0, 0, 0); way_out = 3; goto done_with_input; } if (nxt_pkt == 0) { if (rack->r_wanted_output != 0) { did_out = 1; (void)tp->t_fb->tfb_tcp_output(tp); } rack_start_hpts_timer(rack, tp, cts, __LINE__, 0, 0, 0); } if (((rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) == 0) && (SEQ_GT(tp->snd_max, tp->snd_una) || (tp->t_flags & TF_DELACK) || ((tcp_always_keepalive || rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) && (tp->t_state <= TCPS_CLOSING)))) { /* We could not send (probably in the hpts but stopped the timer earlier)? */ if ((tp->snd_max == tp->snd_una) && ((tp->t_flags & TF_DELACK) == 0) && (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) { /* keep alive not needed if we are hptsi output yet */ ; } else { if (rack->rc_inp->inp_in_hpts) tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT); rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), __LINE__, 0, 0, 0); } way_out = 1; } else { /* Do we have the correct timer running? */ rack_timer_audit(tp, rack, &so->so_snd); way_out = 2; } done_with_input: rack_log_doseg_done(rack, cts, nxt_pkt, did_out, way_out); if (did_out) rack->r_wanted_output = 0; #ifdef INVARIANTS if (tp->t_inpcb == NULL) { panic("OP:%d retval:%d tp:%p t_inpcb:NULL state:%d", did_out, retval, tp, prev_state); } #endif INP_WUNLOCK(tp->t_inpcb); } } void rack_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos) { struct timeval tv; #ifdef RSS struct tcp_function_block *tfb; struct tcp_rack *rack; struct epoch_tracker et; rack = (struct tcp_rack *)tp->t_fb_ptr; if (rack->r_state == 0) { /* * Initial input (ACK to SYN-ACK etc)lets go ahead and get * it processed */ INP_INFO_RLOCK_ET(&V_tcbinfo, et); tcp_get_usecs(&tv); rack_hpts_do_segment(m, th, so, tp, drop_hdrlen, tlen, iptos, 0, &tv); INP_INFO_RUNLOCK_ET(&V_tcbinfo, et); return; } tcp_queue_to_input(tp, m, th, tlen, drop_hdrlen, iptos); INP_WUNLOCK(tp->t_inpcb); #else tcp_get_usecs(&tv); rack_hpts_do_segment(m, th, so, tp, drop_hdrlen, tlen, iptos, 0, &tv); #endif } struct rack_sendmap * tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack, uint32_t tsused) { struct rack_sendmap *rsm = NULL; int32_t idx; uint32_t srtt_cur, srtt = 0, thresh = 0, ts_low = 0; /* Return the next guy to be re-transmitted */ if (TAILQ_EMPTY(&rack->r_ctl.rc_map)) { return (NULL); } if (tp->t_flags & TF_SENTFIN) { /* retran the end FIN? */ return (NULL); } /* ok lets look at this one */ rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap); if (rsm && ((rsm->r_flags & RACK_ACKED) == 0)) { goto check_it; } rsm = rack_find_lowest_rsm(rack); if (rsm == NULL) { return (NULL); } check_it: srtt_cur = tp->t_srtt >> TCP_RTT_SHIFT; srtt = TICKS_2_MSEC(srtt_cur); if (rack->rc_rack_rtt && (srtt > rack->rc_rack_rtt)) srtt = rack->rc_rack_rtt; if (rsm->r_flags & RACK_ACKED) { return (NULL); } if ((rsm->r_flags & RACK_SACK_PASSED) == 0) { /* Its not yet ready */ return (NULL); } idx = rsm->r_rtr_cnt - 1; ts_low = rsm->r_tim_lastsent[idx]; thresh = rack_calc_thresh_rack(rack, srtt, tsused); if (tsused <= ts_low) { return (NULL); } if ((tsused - ts_low) >= thresh) { return (rsm); } return (NULL); } static int rack_output(struct tcpcb *tp) { struct socket *so; uint32_t recwin, sendwin; uint32_t sb_offset; int32_t len, flags, error = 0; struct mbuf *m; struct mbuf *mb; uint32_t if_hw_tsomaxsegcount = 0; uint32_t if_hw_tsomaxsegsize; long tot_len_this_send = 0; struct ip *ip = NULL; #ifdef TCPDEBUG struct ipovly *ipov = NULL; #endif struct udphdr *udp = NULL; struct tcp_rack *rack; struct tcphdr *th; uint8_t pass = 0; uint8_t wanted_cookie = 0; u_char opt[TCP_MAXOLEN]; unsigned ipoptlen, optlen, hdrlen, ulen=0; uint32_t rack_seq; #if defined(IPSEC) || defined(IPSEC_SUPPORT) unsigned ipsec_optlen = 0; #endif int32_t idle, sendalot; int32_t sub_from_prr = 0; volatile int32_t sack_rxmit; struct rack_sendmap *rsm = NULL; int32_t tso, mtu, would_have_fin = 0; struct tcpopt to; int32_t slot = 0; uint32_t cts; uint8_t hpts_calling, doing_tlp = 0; int32_t do_a_prefetch; int32_t prefetch_rsm = 0; int32_t prefetch_so_done = 0; struct tcp_log_buffer *lgb = NULL; struct inpcb *inp; struct sockbuf *sb; #ifdef INET6 struct ip6_hdr *ip6 = NULL; int32_t isipv6; #endif /* setup and take the cache hits here */ rack = (struct tcp_rack *)tp->t_fb_ptr; inp = rack->rc_inp; so = inp->inp_socket; sb = &so->so_snd; kern_prefetch(sb, &do_a_prefetch); do_a_prefetch = 1; INP_WLOCK_ASSERT(inp); #ifdef TCP_OFFLOAD if (tp->t_flags & TF_TOE) return (tcp_offload_output(tp)); #endif #ifdef INET6 if (rack->r_state) { /* Use the cache line loaded if possible */ isipv6 = rack->r_is_v6; } else { isipv6 = (inp->inp_vflag & INP_IPV6) != 0; } #endif cts = tcp_ts_getticks(); if (((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0) && inp->inp_in_hpts) { /* * We are on the hpts for some timer but not hptsi output. * Remove from the hpts unconditionally. */ rack_timer_cancel(tp, rack, cts, __LINE__); } /* Mark that we have called rack_output(). */ if ((rack->r_timer_override) || (tp->t_flags & TF_FORCEDATA) || (tp->t_state < TCPS_ESTABLISHED)) { if (tp->t_inpcb->inp_in_hpts) tcp_hpts_remove(tp->t_inpcb, HPTS_REMOVE_OUTPUT); } else if (tp->t_inpcb->inp_in_hpts) { /* * On the hpts you can't pass even if ACKNOW is on, we will * when the hpts fires. */ counter_u64_add(rack_out_size[TCP_MSS_ACCT_INPACE], 1); return (0); } hpts_calling = inp->inp_hpts_calls; inp->inp_hpts_calls = 0; if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) { if (rack_process_timers(tp, rack, cts, hpts_calling)) { counter_u64_add(rack_out_size[TCP_MSS_ACCT_ATIMER], 1); return (0); } } rack->r_wanted_output = 0; rack->r_timer_override = 0; /* * For TFO connections in SYN_SENT or SYN_RECEIVED, * only allow the initial SYN or SYN|ACK and those sent * by the retransmit timer. */ if (IS_FASTOPEN(tp->t_flags) && ((tp->t_state == TCPS_SYN_RECEIVED) || (tp->t_state == TCPS_SYN_SENT)) && SEQ_GT(tp->snd_max, tp->snd_una) && /* initial SYN or SYN|ACK sent */ (tp->t_rxtshift == 0)) /* not a retransmit */ return (0); /* * Determine length of data that should be transmitted, and flags * that will be used. If there is some data or critical controls * (SYN, RST) to send, then transmit; otherwise, investigate * further. */ idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una); #ifdef NETFLIX_CWV if (tp->cwv_enabled) { if ((tp->cwv_cwnd_valid == 0) && TCPS_HAVEESTABLISHED(tp->t_state) && (tp->snd_cwnd > tp->snd_cwv.init_cwnd)) tcp_newcwv_nvp_closedown(tp); } else #endif if (tp->t_idle_reduce) { if (idle && ((ticks - tp->t_rcvtime) >= tp->t_rxtcur)) rack_cc_after_idle(tp, (rack->r_idle_reduce_largest ? 1 :0)); } tp->t_flags &= ~TF_LASTIDLE; if (idle) { if (tp->t_flags & TF_MORETOCOME) { tp->t_flags |= TF_LASTIDLE; idle = 0; } } again: /* * If we've recently taken a timeout, snd_max will be greater than * snd_nxt. There may be SACK information that allows us to avoid * resending already delivered data. Adjust snd_nxt accordingly. */ sendalot = 0; cts = tcp_ts_getticks(); tso = 0; mtu = 0; sb_offset = tp->snd_max - tp->snd_una; sendwin = min(tp->snd_wnd, tp->snd_cwnd); flags = tcp_outflags[tp->t_state]; /* * Send any SACK-generated retransmissions. If we're explicitly * trying to send out new data (when sendalot is 1), bypass this * function. If we retransmit in fast recovery mode, decrement * snd_cwnd, since we're replacing a (future) new transmission with * a retransmission now, and we previously incremented snd_cwnd in * tcp_input(). */ /* * Still in sack recovery , reset rxmit flag to zero. */ while (rack->rc_free_cnt < rack_free_cache) { rsm = rack_alloc(rack); if (rsm == NULL) { if (inp->inp_hpts_calls) /* Retry in a ms */ slot = 1; goto just_return_nolock; } TAILQ_INSERT_TAIL(&rack->r_ctl.rc_free, rsm, r_next); rack->rc_free_cnt++; rsm = NULL; } if (inp->inp_hpts_calls) inp->inp_hpts_calls = 0; sack_rxmit = 0; len = 0; rsm = NULL; if (flags & TH_RST) { SOCKBUF_LOCK(sb); goto send; } if (rack->r_ctl.rc_tlpsend) { /* Tail loss probe */ long cwin; long tlen; doing_tlp = 1; rsm = rack->r_ctl.rc_tlpsend; rack->r_ctl.rc_tlpsend = NULL; sack_rxmit = 1; tlen = rsm->r_end - rsm->r_start; if (tlen > tp->t_maxseg) tlen = tp->t_maxseg; KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start), ("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p", __func__, __LINE__, rsm->r_start, tp->snd_una, tp, rack, rsm)); sb_offset = rsm->r_start - tp->snd_una; cwin = min(tp->snd_wnd, tlen); len = cwin; } else if (rack->r_ctl.rc_resend) { /* Retransmit timer */ rsm = rack->r_ctl.rc_resend; rack->r_ctl.rc_resend = NULL; len = rsm->r_end - rsm->r_start; sack_rxmit = 1; sendalot = 0; KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start), ("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p", __func__, __LINE__, rsm->r_start, tp->snd_una, tp, rack, rsm)); sb_offset = rsm->r_start - tp->snd_una; if (len >= tp->t_maxseg) { len = tp->t_maxseg; } } else if ((rack->rc_in_persist == 0) && ((rsm = tcp_rack_output(tp, rack, cts)) != NULL)) { long tlen; if ((!IN_RECOVERY(tp->t_flags)) && ((tp->t_flags & (TF_WASFRECOVERY | TF_WASCRECOVERY)) == 0)) { /* Enter recovery if not induced by a time-out */ rack->r_ctl.rc_rsm_start = rsm->r_start; rack->r_ctl.rc_cwnd_at = tp->snd_cwnd; rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh; rack_cong_signal(tp, NULL, CC_NDUPACK); /* * When we enter recovery we need to assure we send * one packet. */ rack->r_ctl.rc_prr_sndcnt = tp->t_maxseg; } #ifdef INVARIANTS if (SEQ_LT(rsm->r_start, tp->snd_una)) { panic("Huh, tp:%p rack:%p rsm:%p start:%u < snd_una:%u\n", tp, rack, rsm, rsm->r_start, tp->snd_una); } #endif tlen = rsm->r_end - rsm->r_start; KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start), ("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p", __func__, __LINE__, rsm->r_start, tp->snd_una, tp, rack, rsm)); sb_offset = rsm->r_start - tp->snd_una; if (tlen > rack->r_ctl.rc_prr_sndcnt) { len = rack->r_ctl.rc_prr_sndcnt; } else { len = tlen; } if (len >= tp->t_maxseg) { sendalot = 1; len = tp->t_maxseg; } else { sendalot = 0; if ((rack->rc_timer_up == 0) && (len < tlen)) { /* * If its not a timer don't send a partial * segment. */ len = 0; goto just_return_nolock; } } if (len > 0) { sub_from_prr = 1; sack_rxmit = 1; TCPSTAT_INC(tcps_sack_rexmits); TCPSTAT_ADD(tcps_sack_rexmit_bytes, min(len, tp->t_maxseg)); counter_u64_add(rack_rtm_prr_retran, 1); } } if (rsm && (rsm->r_flags & RACK_HAS_FIN)) { /* we are retransmitting the fin */ len--; if (len) { /* * When retransmitting data do *not* include the * FIN. This could happen from a TLP probe. */ flags &= ~TH_FIN; } } #ifdef INVARIANTS /* For debugging */ rack->r_ctl.rc_rsm_at_retran = rsm; #endif /* * Get standard flags, and add SYN or FIN if requested by 'hidden' * state flags. */ if (tp->t_flags & TF_NEEDFIN) flags |= TH_FIN; if (tp->t_flags & TF_NEEDSYN) flags |= TH_SYN; if ((sack_rxmit == 0) && (prefetch_rsm == 0)) { void *end_rsm; end_rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext); if (end_rsm) kern_prefetch(end_rsm, &prefetch_rsm); prefetch_rsm = 1; } SOCKBUF_LOCK(sb); /* * If in persist timeout with window of 0, send 1 byte. Otherwise, * if window is small but nonzero and time TF_SENTFIN expired, we * will send what we can and go to transmit state. */ if (tp->t_flags & TF_FORCEDATA) { if (sendwin == 0) { /* * If we still have some data to send, then clear * the FIN bit. Usually this would happen below * when it realizes that we aren't sending all the * data. However, if we have exactly 1 byte of * unsent data, then it won't clear the FIN bit * below, and if we are in persist state, we wind up * sending the packet without recording that we sent * the FIN bit. * * We can't just blindly clear the FIN bit, because * if we don't have any more data to send then the * probe will be the FIN itself. */ if (sb_offset < sbused(sb)) flags &= ~TH_FIN; sendwin = 1; } else { if (rack->rc_in_persist) rack_exit_persist(tp, rack); /* * If we are dropping persist mode then we need to * correct snd_nxt/snd_max and off. */ tp->snd_nxt = tp->snd_max; sb_offset = tp->snd_nxt - tp->snd_una; } } /* * If snd_nxt == snd_max and we have transmitted a FIN, the * sb_offset will be > 0 even if so_snd.sb_cc is 0, resulting in a * negative length. This can also occur when TCP opens up its * congestion window while receiving additional duplicate acks after * fast-retransmit because TCP will reset snd_nxt to snd_max after * the fast-retransmit. * * In the normal retransmit-FIN-only case, however, snd_nxt will be * set to snd_una, the sb_offset will be 0, and the length may wind * up 0. * * If sack_rxmit is true we are retransmitting from the scoreboard * in which case len is already set. */ if (sack_rxmit == 0) { uint32_t avail; avail = sbavail(sb); if (SEQ_GT(tp->snd_nxt, tp->snd_una) && avail) sb_offset = tp->snd_nxt - tp->snd_una; else sb_offset = 0; if (IN_RECOVERY(tp->t_flags) == 0) { if (rack->r_ctl.rc_tlp_new_data) { /* TLP is forcing out new data */ if (rack->r_ctl.rc_tlp_new_data > (uint32_t) (avail - sb_offset)) { rack->r_ctl.rc_tlp_new_data = (uint32_t) (avail - sb_offset); } if (rack->r_ctl.rc_tlp_new_data > tp->snd_wnd) len = tp->snd_wnd; else len = rack->r_ctl.rc_tlp_new_data; rack->r_ctl.rc_tlp_new_data = 0; doing_tlp = 1; } else { if (sendwin > avail) { /* use the available */ if (avail > sb_offset) { len = (int32_t)(avail - sb_offset); } else { len = 0; } } else { if (sendwin > sb_offset) { len = (int32_t)(sendwin - sb_offset); } else { len = 0; } } } } else { uint32_t outstanding; /* * We are inside of a SACK recovery episode and are * sending new data, having retransmitted all the * data possible so far in the scoreboard. */ outstanding = tp->snd_max - tp->snd_una; if ((rack->r_ctl.rc_prr_sndcnt + outstanding) > tp->snd_wnd) len = 0; else if (avail > sb_offset) len = avail - sb_offset; else len = 0; if (len > 0) { if (len > rack->r_ctl.rc_prr_sndcnt) len = rack->r_ctl.rc_prr_sndcnt; if (len > 0) { sub_from_prr = 1; counter_u64_add(rack_rtm_prr_newdata, 1); } } if (len > tp->t_maxseg) { /* * We should never send more than a MSS when * retransmitting or sending new data in prr * mode unless the override flag is on. Most * likely the PRR algorithm is not going to * let us send a lot as well :-) */ if (rack->r_ctl.rc_prr_sendalot == 0) len = tp->t_maxseg; } else if (len < tp->t_maxseg) { /* * Do we send any? The idea here is if the * send empty's the socket buffer we want to * do it. However if not then lets just wait * for our prr_sndcnt to get bigger. */ long leftinsb; leftinsb = sbavail(sb) - sb_offset; if (leftinsb > len) { /* This send does not empty the sb */ len = 0; } } } } if (prefetch_so_done == 0) { kern_prefetch(so, &prefetch_so_done); prefetch_so_done = 1; } /* * Lop off SYN bit if it has already been sent. However, if this is * SYN-SENT state and if segment contains data and if we don't know * that foreign host supports TAO, suppress sending segment. */ if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una) && ((sack_rxmit == 0) && (tp->t_rxtshift == 0))) { if (tp->t_state != TCPS_SYN_RECEIVED) flags &= ~TH_SYN; /* * When sending additional segments following a TFO SYN|ACK, * do not include the SYN bit. */ if (IS_FASTOPEN(tp->t_flags) && (tp->t_state == TCPS_SYN_RECEIVED)) flags &= ~TH_SYN; sb_offset--, len++; } /* * Be careful not to send data and/or FIN on SYN segments. This * measure is needed to prevent interoperability problems with not * fully conformant TCP implementations. */ if ((flags & TH_SYN) && (tp->t_flags & TF_NOOPT)) { len = 0; flags &= ~TH_FIN; } /* * On TFO sockets, ensure no data is sent in the following cases: * * - When retransmitting SYN|ACK on a passively-created socket * * - When retransmitting SYN on an actively created socket * * - When sending a zero-length cookie (cookie request) on an * actively created socket * * - When the socket is in the CLOSED state (RST is being sent) */ if (IS_FASTOPEN(tp->t_flags) && (((flags & TH_SYN) && (tp->t_rxtshift > 0)) || ((tp->t_state == TCPS_SYN_SENT) && (tp->t_tfo_client_cookie_len == 0)) || (flags & TH_RST))) { sack_rxmit = 0; len = 0; } /* Without fast-open there should never be data sent on a SYN */ if ((flags & TH_SYN) && (!IS_FASTOPEN(tp->t_flags))) len = 0; if (len <= 0) { /* * If FIN has been sent but not acked, but we haven't been * called to retransmit, len will be < 0. Otherwise, window * shrank after we sent into it. If window shrank to 0, * cancel pending retransmit, pull snd_nxt back to (closed) * window, and set the persist timer if it isn't already * going. If the window didn't close completely, just wait * for an ACK. * * We also do a general check here to ensure that we will * set the persist timer when we have data to send, but a * 0-byte window. This makes sure the persist timer is set * even if the packet hits one of the "goto send" lines * below. */ len = 0; if ((tp->snd_wnd == 0) && (TCPS_HAVEESTABLISHED(tp->t_state)) && (sb_offset < (int)sbavail(sb))) { tp->snd_nxt = tp->snd_una; rack_enter_persist(tp, rack, cts); } } /* len will be >= 0 after this point. */ KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__)); tcp_sndbuf_autoscale(tp, so, sendwin); /* * Decide if we can use TCP Segmentation Offloading (if supported by * hardware). * * TSO may only be used if we are in a pure bulk sending state. The * presence of TCP-MD5, SACK retransmits, SACK advertizements and IP * options prevent using TSO. With TSO the TCP header is the same * (except for the sequence number) for all generated packets. This * makes it impossible to transmit any options which vary per * generated segment or packet. * * IPv4 handling has a clear separation of ip options and ip header * flags while IPv6 combines both in in6p_outputopts. ip6_optlen() does * the right thing below to provide length of just ip options and thus * checking for ipoptlen is enough to decide if ip options are present. */ #ifdef INET6 if (isipv6) ipoptlen = ip6_optlen(tp->t_inpcb); else #endif if (tp->t_inpcb->inp_options) ipoptlen = tp->t_inpcb->inp_options->m_len - offsetof(struct ipoption, ipopt_list); else ipoptlen = 0; #if defined(IPSEC) || defined(IPSEC_SUPPORT) /* * Pre-calculate here as we save another lookup into the darknesses * of IPsec that way and can actually decide if TSO is ok. */ #ifdef INET6 if (isipv6 && IPSEC_ENABLED(ipv6)) ipsec_optlen = IPSEC_HDRSIZE(ipv6, tp->t_inpcb); #ifdef INET else #endif #endif /* INET6 */ #ifdef INET if (IPSEC_ENABLED(ipv4)) ipsec_optlen = IPSEC_HDRSIZE(ipv4, tp->t_inpcb); #endif /* INET */ #endif #if defined(IPSEC) || defined(IPSEC_SUPPORT) ipoptlen += ipsec_optlen; #endif if ((tp->t_flags & TF_TSO) && V_tcp_do_tso && len > tp->t_maxseg && (tp->t_port == 0) && ((tp->t_flags & TF_SIGNATURE) == 0) && tp->rcv_numsacks == 0 && sack_rxmit == 0 && ipoptlen == 0) tso = 1; { uint32_t outstanding; outstanding = tp->snd_max - tp->snd_una; if (tp->t_flags & TF_SENTFIN) { /* * If we sent a fin, snd_max is 1 higher than * snd_una */ outstanding--; } if (outstanding > 0) { /* * This is sub-optimal. We only send a stand alone * FIN on its own segment. */ if (flags & TH_FIN) { flags &= ~TH_FIN; would_have_fin = 1; } } else if (sack_rxmit) { if ((rsm->r_flags & RACK_HAS_FIN) == 0) flags &= ~TH_FIN; } else { if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + sbused(sb))) flags &= ~TH_FIN; } } recwin = sbspace(&so->so_rcv); /* * Sender silly window avoidance. We transmit under the following * conditions when len is non-zero: * * - We have a full segment (or more with TSO) - This is the last * buffer in a write()/send() and we are either idle or running * NODELAY - we've timed out (e.g. persist timer) - we have more * then 1/2 the maximum send window's worth of data (receiver may be * limited the window size) - we need to retransmit */ if (len) { if (len >= tp->t_maxseg) { pass = 1; goto send; } /* * NOTE! on localhost connections an 'ack' from the remote * end may occur synchronously with the output and cause us * to flush a buffer queued with moretocome. XXX * */ if (!(tp->t_flags & TF_MORETOCOME) && /* normal case */ (idle || (tp->t_flags & TF_NODELAY)) && ((uint32_t)len + (uint32_t)sb_offset >= sbavail(&so->so_snd)) && (tp->t_flags & TF_NOPUSH) == 0) { pass = 2; goto send; } if (tp->t_flags & TF_FORCEDATA) { /* typ. timeout case */ pass = 3; goto send; } if ((tp->snd_una == tp->snd_max) && len) { /* Nothing outstanding */ goto send; } if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) { pass = 4; goto send; } if (SEQ_LT(tp->snd_nxt, tp->snd_max)) { /* retransmit case */ pass = 5; goto send; } if (sack_rxmit) { pass = 6; goto send; } } /* * Sending of standalone window updates. * * Window updates are important when we close our window due to a * full socket buffer and are opening it again after the application * reads data from it. Once the window has opened again and the * remote end starts to send again the ACK clock takes over and * provides the most current window information. * * We must avoid the silly window syndrome whereas every read from * the receive buffer, no matter how small, causes a window update * to be sent. We also should avoid sending a flurry of window * updates when the socket buffer had queued a lot of data and the * application is doing small reads. * * Prevent a flurry of pointless window updates by only sending an * update when we can increase the advertized window by more than * 1/4th of the socket buffer capacity. When the buffer is getting * full or is very small be more aggressive and send an update * whenever we can increase by two mss sized segments. In all other * situations the ACK's to new incoming data will carry further * window increases. * * Don't send an independent window update if a delayed ACK is * pending (it will get piggy-backed on it) or the remote side * already has done a half-close and won't send more data. Skip * this if the connection is in T/TCP half-open state. */ if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN) && !(tp->t_flags & TF_DELACK) && !TCPS_HAVERCVDFIN(tp->t_state)) { /* * "adv" is the amount we could increase the window, taking * into account that we are limited by TCP_MAXWIN << * tp->rcv_scale. */ int32_t adv; int oldwin; adv = min(recwin, (long)TCP_MAXWIN << tp->rcv_scale); if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) { oldwin = (tp->rcv_adv - tp->rcv_nxt); adv -= oldwin; } else oldwin = 0; /* * If the new window size ends up being the same as the old * size when it is scaled, then don't force a window update. */ if (oldwin >> tp->rcv_scale == (adv + oldwin) >> tp->rcv_scale) goto dontupdate; if (adv >= (int32_t)(2 * tp->t_maxseg) && (adv >= (int32_t)(so->so_rcv.sb_hiwat / 4) || recwin <= (int32_t)(so->so_rcv.sb_hiwat / 8) || so->so_rcv.sb_hiwat <= 8 * tp->t_maxseg)) { pass = 7; goto send; } if (2 * adv >= (int32_t) so->so_rcv.sb_hiwat) goto send; } dontupdate: /* * Send if we owe the peer an ACK, RST, SYN, or urgent data. ACKNOW * is also a catch-all for the retransmit timer timeout case. */ if (tp->t_flags & TF_ACKNOW) { pass = 8; goto send; } if (((flags & TH_SYN) && (tp->t_flags & TF_NEEDSYN) == 0)) { pass = 9; goto send; } if (SEQ_GT(tp->snd_up, tp->snd_una)) { pass = 10; goto send; } /* * If our state indicates that FIN should be sent and we have not * yet done so, then we need to send. */ if ((flags & TH_FIN) && (tp->snd_nxt == tp->snd_una)) { pass = 11; goto send; } /* * No reason to send a segment, just return. */ just_return: SOCKBUF_UNLOCK(sb); just_return_nolock: if (tot_len_this_send == 0) counter_u64_add(rack_out_size[TCP_MSS_ACCT_JUSTRET], 1); rack_start_hpts_timer(rack, tp, cts, __LINE__, slot, tot_len_this_send, 1); rack_log_type_just_return(rack, cts, tot_len_this_send, slot, hpts_calling); tp->t_flags &= ~TF_FORCEDATA; return (0); send: if (doing_tlp == 0) { /* * Data not a TLP, and its not the rxt firing. If it is the * rxt firing, we want to leave the tlp_in_progress flag on * so we don't send another TLP. It has to be a rack timer * or normal send (response to acked data) to clear the tlp * in progress flag. */ rack->rc_tlp_in_progress = 0; } SOCKBUF_LOCK_ASSERT(sb); if (len > 0) { if (len >= tp->t_maxseg) tp->t_flags2 |= TF2_PLPMTU_MAXSEGSNT; else tp->t_flags2 &= ~TF2_PLPMTU_MAXSEGSNT; } /* * Before ESTABLISHED, force sending of initial options unless TCP * set not to do any options. NOTE: we assume that the IP/TCP header * plus TCP options always fit in a single mbuf, leaving room for a * maximum link header, i.e. max_linkhdr + sizeof (struct tcpiphdr) * + optlen <= MCLBYTES */ optlen = 0; #ifdef INET6 if (isipv6) hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); else #endif hdrlen = sizeof(struct tcpiphdr); /* * Compute options for segment. We only have to care about SYN and * established connection segments. Options for SYN-ACK segments * are handled in TCP syncache. */ to.to_flags = 0; if ((tp->t_flags & TF_NOOPT) == 0) { /* Maximum segment size. */ if (flags & TH_SYN) { tp->snd_nxt = tp->iss; to.to_mss = tcp_mssopt(&inp->inp_inc); #ifdef NETFLIX_TCPOUDP if (tp->t_port) to.to_mss -= V_tcp_udp_tunneling_overhead; #endif to.to_flags |= TOF_MSS; /* * On SYN or SYN|ACK transmits on TFO connections, * only include the TFO option if it is not a * retransmit, as the presence of the TFO option may * have caused the original SYN or SYN|ACK to have * been dropped by a middlebox. */ if (IS_FASTOPEN(tp->t_flags) && (tp->t_rxtshift == 0)) { if (tp->t_state == TCPS_SYN_RECEIVED) { to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN; to.to_tfo_cookie = (u_int8_t *)&tp->t_tfo_cookie.server; to.to_flags |= TOF_FASTOPEN; wanted_cookie = 1; } else if (tp->t_state == TCPS_SYN_SENT) { to.to_tfo_len = tp->t_tfo_client_cookie_len; to.to_tfo_cookie = tp->t_tfo_cookie.client; to.to_flags |= TOF_FASTOPEN; wanted_cookie = 1; /* * If we wind up having more data to * send with the SYN than can fit in * one segment, don't send any more * until the SYN|ACK comes back from * the other end. */ sendalot = 0; } } } /* Window scaling. */ if ((flags & TH_SYN) && (tp->t_flags & TF_REQ_SCALE)) { to.to_wscale = tp->request_r_scale; to.to_flags |= TOF_SCALE; } /* Timestamps. */ if ((tp->t_flags & TF_RCVD_TSTMP) || ((flags & TH_SYN) && (tp->t_flags & TF_REQ_TSTMP))) { to.to_tsval = cts + tp->ts_offset; to.to_tsecr = tp->ts_recent; to.to_flags |= TOF_TS; } /* Set receive buffer autosizing timestamp. */ if (tp->rfbuf_ts == 0 && (so->so_rcv.sb_flags & SB_AUTOSIZE)) tp->rfbuf_ts = tcp_ts_getticks(); /* Selective ACK's. */ if (flags & TH_SYN) to.to_flags |= TOF_SACKPERM; else if (TCPS_HAVEESTABLISHED(tp->t_state) && tp->rcv_numsacks > 0) { to.to_flags |= TOF_SACK; to.to_nsacks = tp->rcv_numsacks; to.to_sacks = (u_char *)tp->sackblks; } #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE) /* TCP-MD5 (RFC2385). */ if (tp->t_flags & TF_SIGNATURE) to.to_flags |= TOF_SIGNATURE; #endif /* TCP_SIGNATURE */ /* Processing the options. */ hdrlen += optlen = tcp_addoptions(&to, opt); /* * If we wanted a TFO option to be added, but it was unable * to fit, ensure no data is sent. */ if (IS_FASTOPEN(tp->t_flags) && wanted_cookie && !(to.to_flags & TOF_FASTOPEN)) len = 0; } #ifdef NETFLIX_TCPOUDP if (tp->t_port) { if (V_tcp_udp_tunneling_port == 0) { /* The port was removed?? */ SOCKBUF_UNLOCK(&so->so_snd); return (EHOSTUNREACH); } hdrlen += sizeof(struct udphdr); } #endif ipoptlen = 0; #if defined(IPSEC) || defined(IPSEC_SUPPORT) ipoptlen += ipsec_optlen; #endif /* * Adjust data length if insertion of options will bump the packet * length beyond the t_maxseg length. Clear the FIN bit because we * cut off the tail of the segment. */ if (len + optlen + ipoptlen > tp->t_maxseg) { if (flags & TH_FIN) { would_have_fin = 1; flags &= ~TH_FIN; } if (tso) { uint32_t if_hw_tsomax; uint32_t moff; int32_t max_len; /* extract TSO information */ if_hw_tsomax = tp->t_tsomax; if_hw_tsomaxsegcount = tp->t_tsomaxsegcount; if_hw_tsomaxsegsize = tp->t_tsomaxsegsize; KASSERT(ipoptlen == 0, ("%s: TSO can't do IP options", __func__)); /* * Check if we should limit by maximum payload * length: */ if (if_hw_tsomax != 0) { /* compute maximum TSO length */ max_len = (if_hw_tsomax - hdrlen - max_linkhdr); if (max_len <= 0) { len = 0; } else if (len > max_len) { sendalot = 1; len = max_len; } } /* * Prevent the last segment from being fractional * unless the send sockbuf can be emptied: */ max_len = (tp->t_maxseg - optlen); if ((sb_offset + len) < sbavail(sb)) { moff = len % (u_int)max_len; if (moff != 0) { len -= moff; sendalot = 1; } } /* * In case there are too many small fragments don't * use TSO: */ if (len <= max_len) { len = max_len; sendalot = 1; tso = 0; } /* * Send the FIN in a separate segment after the bulk * sending is done. We don't trust the TSO * implementations to clear the FIN flag on all but * the last segment. */ if (tp->t_flags & TF_NEEDFIN) sendalot = 1; } else { len = tp->t_maxseg - optlen - ipoptlen; sendalot = 1; } } else tso = 0; KASSERT(len + hdrlen + ipoptlen <= IP_MAXPACKET, ("%s: len > IP_MAXPACKET", __func__)); #ifdef DIAGNOSTIC #ifdef INET6 if (max_linkhdr + hdrlen > MCLBYTES) #else if (max_linkhdr + hdrlen > MHLEN) #endif panic("tcphdr too big"); #endif /* * This KASSERT is here to catch edge cases at a well defined place. * Before, those had triggered (random) panic conditions further * down. */ KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__)); if ((len == 0) && (flags & TH_FIN) && (sbused(sb))) { /* * We have outstanding data, don't send a fin by itself!. */ goto just_return; } /* * Grab a header mbuf, attaching a copy of data to be transmitted, * and initialize the header from the template for sends on this * connection. */ if (len) { uint32_t max_val; uint32_t moff; if (rack->rc_pace_max_segs) max_val = rack->rc_pace_max_segs * tp->t_maxseg; else max_val = len; /* * We allow a limit on sending with hptsi. */ if (len > max_val) { len = max_val; } #ifdef INET6 if (MHLEN < hdrlen + max_linkhdr) m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR); else #endif m = m_gethdr(M_NOWAIT, MT_DATA); if (m == NULL) { SOCKBUF_UNLOCK(sb); error = ENOBUFS; sack_rxmit = 0; goto out; } m->m_data += max_linkhdr; m->m_len = hdrlen; /* * Start the m_copy functions from the closest mbuf to the * sb_offset in the socket buffer chain. */ mb = sbsndptr_noadv(sb, sb_offset, &moff); if (len <= MHLEN - hdrlen - max_linkhdr) { m_copydata(mb, moff, (int)len, mtod(m, caddr_t)+hdrlen); if (SEQ_LT(tp->snd_nxt, tp->snd_max)) sbsndptr_adv(sb, mb, len); m->m_len += len; } else { struct sockbuf *msb; if (SEQ_LT(tp->snd_nxt, tp->snd_max)) msb = NULL; else msb = sb; m->m_next = tcp_m_copym(mb, moff, &len, if_hw_tsomaxsegcount, if_hw_tsomaxsegsize, msb); if (len <= (tp->t_maxseg - optlen)) { /* * Must have ran out of mbufs for the copy * shorten it to no longer need tso. Lets * not put on sendalot since we are low on * mbufs. */ tso = 0; } if (m->m_next == NULL) { SOCKBUF_UNLOCK(sb); (void)m_free(m); error = ENOBUFS; sack_rxmit = 0; goto out; } } if ((tp->t_flags & TF_FORCEDATA) && len == 1) { TCPSTAT_INC(tcps_sndprobe); #ifdef NETFLIX_STATS if (SEQ_LT(tp->snd_nxt, tp->snd_max)) stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB, len); else stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB, len); #endif } else if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) { if (rsm && (rsm->r_flags & RACK_TLP)) { /* * TLP should not count in retran count, but * in its own bin */ counter_u64_add(rack_tlp_retran, 1); counter_u64_add(rack_tlp_retran_bytes, len); } else { tp->t_sndrexmitpack++; TCPSTAT_INC(tcps_sndrexmitpack); TCPSTAT_ADD(tcps_sndrexmitbyte, len); } #ifdef NETFLIX_STATS stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB, len); #endif } else { TCPSTAT_INC(tcps_sndpack); TCPSTAT_ADD(tcps_sndbyte, len); #ifdef NETFLIX_STATS stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB, len); #endif } /* * If we're sending everything we've got, set PUSH. (This * will keep happy those implementations which only give * data to the user when a buffer fills or a PUSH comes in.) */ if (sb_offset + len == sbused(sb) && sbused(sb) && !(flags & TH_SYN)) flags |= TH_PUSH; /* * Are we doing hptsi, if so we must calculate the slot. We * only do hptsi in ESTABLISHED and with no RESET being * sent where we have data to send. */ if (((tp->t_state == TCPS_ESTABLISHED) || (tp->t_state == TCPS_CLOSE_WAIT) || ((tp->t_state == TCPS_FIN_WAIT_1) && ((tp->t_flags & TF_SENTFIN) == 0) && ((flags & TH_FIN) == 0))) && ((flags & TH_RST) == 0) && (rack->rc_always_pace)) { /* * We use the most optimistic possible cwnd/srtt for * sending calculations. This will make our * calculation anticipate getting more through * quicker then possible. But thats ok we don't want * the peer to have a gap in data sending. */ uint32_t srtt, cwnd, tr_perms = 0; if (rack->r_ctl.rc_rack_min_rtt) srtt = rack->r_ctl.rc_rack_min_rtt; else srtt = TICKS_2_MSEC((tp->t_srtt >> TCP_RTT_SHIFT)); if (rack->r_ctl.rc_rack_largest_cwnd) cwnd = rack->r_ctl.rc_rack_largest_cwnd; else cwnd = tp->snd_cwnd; tr_perms = cwnd / srtt; if (tr_perms == 0) { tr_perms = tp->t_maxseg; } tot_len_this_send += len; /* * Calculate how long this will take to drain, if * the calculation comes out to zero, thats ok we * will use send_a_lot to possibly spin around for * more increasing tot_len_this_send to the point * that its going to require a pace, or we hit the * cwnd. Which in that case we are just waiting for * a ACK. */ slot = tot_len_this_send / tr_perms; /* Now do we reduce the time so we don't run dry? */ if (slot && rack->rc_pace_reduce) { int32_t reduce; reduce = (slot / rack->rc_pace_reduce); if (reduce < slot) { slot -= reduce; } else slot = 0; } if (rack->r_enforce_min_pace && (slot == 0) && (tot_len_this_send >= (rack->r_min_pace_seg_thresh * tp->t_maxseg))) { /* We are enforcing a minimum pace time of 1ms */ slot = rack->r_enforce_min_pace; } } SOCKBUF_UNLOCK(sb); } else { SOCKBUF_UNLOCK(sb); if (tp->t_flags & TF_ACKNOW) TCPSTAT_INC(tcps_sndacks); else if (flags & (TH_SYN | TH_FIN | TH_RST)) TCPSTAT_INC(tcps_sndctrl); else if (SEQ_GT(tp->snd_up, tp->snd_una)) TCPSTAT_INC(tcps_sndurg); else TCPSTAT_INC(tcps_sndwinup); m = m_gethdr(M_NOWAIT, MT_DATA); if (m == NULL) { error = ENOBUFS; sack_rxmit = 0; goto out; } #ifdef INET6 if (isipv6 && (MHLEN < hdrlen + max_linkhdr) && MHLEN >= hdrlen) { M_ALIGN(m, hdrlen); } else #endif m->m_data += max_linkhdr; m->m_len = hdrlen; } SOCKBUF_UNLOCK_ASSERT(sb); m->m_pkthdr.rcvif = (struct ifnet *)0; #ifdef MAC mac_inpcb_create_mbuf(inp, m); #endif #ifdef INET6 if (isipv6) { ip6 = mtod(m, struct ip6_hdr *); #ifdef NETFLIX_TCPOUDP if (tp->t_port) { udp = (struct udphdr *)((caddr_t)ip6 + ipoptlen + sizeof(struct ip6_hdr)); udp->uh_sport = htons(V_tcp_udp_tunneling_port); udp->uh_dport = tp->t_port; ulen = hdrlen + len - sizeof(struct ip6_hdr); udp->uh_ulen = htons(ulen); th = (struct tcphdr *)(udp + 1); } else #endif th = (struct tcphdr *)(ip6 + 1); tcpip_fillheaders(inp, ip6, th); } else #endif /* INET6 */ { ip = mtod(m, struct ip *); #ifdef TCPDEBUG ipov = (struct ipovly *)ip; #endif #ifdef NETFLIX_TCPOUDP if (tp->t_port) { udp = (struct udphdr *)((caddr_t)ip + ipoptlen + sizeof(struct ip)); udp->uh_sport = htons(V_tcp_udp_tunneling_port); udp->uh_dport = tp->t_port; ulen = hdrlen + len - sizeof(struct ip); udp->uh_ulen = htons(ulen); th = (struct tcphdr *)(udp + 1); } else #endif th = (struct tcphdr *)(ip + 1); tcpip_fillheaders(inp, ip, th); } /* * Fill in fields, remembering maximum advertised window for use in * delaying messages about window sizes. If resending a FIN, be sure * not to use a new sequence number. */ if (flags & TH_FIN && tp->t_flags & TF_SENTFIN && tp->snd_nxt == tp->snd_max) tp->snd_nxt--; /* * If we are starting a connection, send ECN setup SYN packet. If we * are on a retransmit, we may resend those bits a number of times * as per RFC 3168. */ if (tp->t_state == TCPS_SYN_SENT && V_tcp_do_ecn == 1) { if (tp->t_rxtshift >= 1) { if (tp->t_rxtshift <= V_tcp_ecn_maxretries) flags |= TH_ECE | TH_CWR; } else flags |= TH_ECE | TH_CWR; } if (tp->t_state == TCPS_ESTABLISHED && (tp->t_flags & TF_ECN_PERMIT)) { /* * If the peer has ECN, mark data packets with ECN capable * transmission (ECT). Ignore pure ack packets, * retransmissions and window probes. */ if (len > 0 && SEQ_GEQ(tp->snd_nxt, tp->snd_max) && !((tp->t_flags & TF_FORCEDATA) && len == 1)) { #ifdef INET6 if (isipv6) ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20); else #endif ip->ip_tos |= IPTOS_ECN_ECT0; TCPSTAT_INC(tcps_ecn_ect0); } /* * Reply with proper ECN notifications. */ if (tp->t_flags & TF_ECN_SND_CWR) { flags |= TH_CWR; tp->t_flags &= ~TF_ECN_SND_CWR; } if (tp->t_flags & TF_ECN_SND_ECE) flags |= TH_ECE; } /* * If we are doing retransmissions, then snd_nxt will not reflect * the first unsent octet. For ACK only packets, we do not want the * sequence number of the retransmitted packet, we want the sequence * number of the next unsent octet. So, if there is no data (and no * SYN or FIN), use snd_max instead of snd_nxt when filling in * ti_seq. But if we are in persist state, snd_max might reflect * one byte beyond the right edge of the window, so use snd_nxt in * that case, since we know we aren't doing a retransmission. * (retransmit and persist are mutually exclusive...) */ if (sack_rxmit == 0) { if (len || (flags & (TH_SYN | TH_FIN)) || rack->rc_in_persist) { th->th_seq = htonl(tp->snd_nxt); rack_seq = tp->snd_nxt; } else if (flags & TH_RST) { /* * For a Reset send the last cum ack in sequence * (this like any other choice may still generate a * challenge ack, if a ack-update packet is in * flight). */ th->th_seq = htonl(tp->snd_una); rack_seq = tp->snd_una; } else { th->th_seq = htonl(tp->snd_max); rack_seq = tp->snd_max; } } else { th->th_seq = htonl(rsm->r_start); rack_seq = rsm->r_start; } th->th_ack = htonl(tp->rcv_nxt); if (optlen) { bcopy(opt, th + 1, optlen); th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; } th->th_flags = flags; /* * Calculate receive window. Don't shrink window, but avoid silly * window syndrome. * If a RST segment is sent, advertise a window of zero. */ if (flags & TH_RST) { recwin = 0; } else { if (recwin < (long)(so->so_rcv.sb_hiwat / 4) && recwin < (long)tp->t_maxseg) recwin = 0; if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt) && recwin < (long)(tp->rcv_adv - tp->rcv_nxt)) recwin = (long)(tp->rcv_adv - tp->rcv_nxt); if (recwin > (long)TCP_MAXWIN << tp->rcv_scale) recwin = (long)TCP_MAXWIN << tp->rcv_scale; } /* * According to RFC1323 the window field in a SYN (i.e., a or * ) segment itself is never scaled. The case is * handled in syncache. */ if (flags & TH_SYN) th->th_win = htons((u_short) (min(sbspace(&so->so_rcv), TCP_MAXWIN))); else th->th_win = htons((u_short)(recwin >> tp->rcv_scale)); /* * Adjust the RXWIN0SENT flag - indicate that we have advertised a 0 * window. This may cause the remote transmitter to stall. This * flag tells soreceive() to disable delayed acknowledgements when * draining the buffer. This can occur if the receiver is * attempting to read more data than can be buffered prior to * transmitting on the connection. */ if (th->th_win == 0) { tp->t_sndzerowin++; tp->t_flags |= TF_RXWIN0SENT; } else tp->t_flags &= ~TF_RXWIN0SENT; if (SEQ_GT(tp->snd_up, tp->snd_nxt)) { th->th_urp = htons((u_short)(tp->snd_up - tp->snd_nxt)); th->th_flags |= TH_URG; } else /* * If no urgent pointer to send, then we pull the urgent * pointer to the left edge of the send window so that it * doesn't drift into the send window on sequence number * wraparound. */ tp->snd_up = tp->snd_una; /* drag it along */ #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE) if (to.to_flags & TOF_SIGNATURE) { /* * Calculate MD5 signature and put it into the place * determined before. * NOTE: since TCP options buffer doesn't point into * mbuf's data, calculate offset and use it. */ if (!TCPMD5_ENABLED() || TCPMD5_OUTPUT(m, th, (u_char *)(th + 1) + (to.to_signature - opt)) != 0) { /* * Do not send segment if the calculation of MD5 * digest has failed. */ goto out; } } #endif /* * Put TCP length in extended header, and then checksum extended * header and data. */ m->m_pkthdr.len = hdrlen + len; /* in6_cksum() need this */ #ifdef INET6 if (isipv6) { /* * ip6_plen is not need to be filled now, and will be filled * in ip6_output. */ if (tp->t_port) { m->m_pkthdr.csum_flags = CSUM_UDP_IPV6; m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum); udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0); th->th_sum = htons(0); } else { m->m_pkthdr.csum_flags = CSUM_TCP_IPV6; m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); th->th_sum = in6_cksum_pseudo(ip6, sizeof(struct tcphdr) + optlen + len, IPPROTO_TCP, 0); } } #endif #if defined(INET6) && defined(INET) else #endif #ifdef INET { if (tp->t_port) { m->m_pkthdr.csum_flags = CSUM_UDP; m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum); udp->uh_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP)); th->th_sum = htons(0); } else { m->m_pkthdr.csum_flags = CSUM_TCP; m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) + IPPROTO_TCP + len + optlen)); } /* IP version must be set here for ipv4/ipv6 checking later */ KASSERT(ip->ip_v == IPVERSION, ("%s: IP version incorrect: %d", __func__, ip->ip_v)); } #endif /* * Enable TSO and specify the size of the segments. The TCP pseudo * header checksum is always provided. XXX: Fixme: This is currently * not the case for IPv6. */ if (tso) { KASSERT(len > tp->t_maxseg - optlen, ("%s: len <= tso_segsz", __func__)); m->m_pkthdr.csum_flags |= CSUM_TSO; m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen; } #if defined(IPSEC) || defined(IPSEC_SUPPORT) KASSERT(len + hdrlen + ipoptlen - ipsec_optlen == m_length(m, NULL), ("%s: mbuf chain shorter than expected: %d + %u + %u - %u != %u", __func__, len, hdrlen, ipoptlen, ipsec_optlen, m_length(m, NULL))); #else KASSERT(len + hdrlen + ipoptlen == m_length(m, NULL), ("%s: mbuf chain shorter than expected: %d + %u + %u != %u", __func__, len, hdrlen, ipoptlen, m_length(m, NULL))); #endif #ifdef TCP_HHOOK /* Run HHOOK_TCP_ESTABLISHED_OUT helper hooks. */ hhook_run_tcp_est_out(tp, th, &to, len, tso); #endif #ifdef TCPDEBUG /* * Trace. */ if (so->so_options & SO_DEBUG) { u_short save = 0; #ifdef INET6 if (!isipv6) #endif { save = ipov->ih_len; ipov->ih_len = htons(m->m_pkthdr.len /* - hdrlen + * (th->th_off << 2) */ ); } tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0); #ifdef INET6 if (!isipv6) #endif ipov->ih_len = save; } #endif /* TCPDEBUG */ /* We're getting ready to send; log now. */ if (tp->t_logstate != TCP_LOG_STATE_OFF) { union tcp_log_stackspecific log; memset(&log.u_bbr, 0, sizeof(log.u_bbr)); log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts; log.u_bbr.ininput = rack->rc_inp->inp_in_input; log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt; if (rsm || sack_rxmit) { log.u_bbr.flex8 = 1; } else { log.u_bbr.flex8 = 0; } lgb = tcp_log_event_(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_OUT, ERRNO_UNK, len, &log, false, NULL, NULL, 0, NULL); } else lgb = NULL; /* * Fill in IP length and desired time to live and send to IP level. * There should be a better way to handle ttl and tos; we could keep * them in the template, but need a way to checksum without them. */ /* * m->m_pkthdr.len should have been set before cksum calcuration, * because in6_cksum() need it. */ #ifdef INET6 if (isipv6) { /* * we separately set hoplimit for every segment, since the * user might want to change the value via setsockopt. Also, * desired default hop limit might be changed via Neighbor * Discovery. */ ip6->ip6_hlim = in6_selecthlim(inp, NULL); /* * Set the packet size here for the benefit of DTrace * probes. ip6_output() will set it properly; it's supposed * to include the option header lengths as well. */ ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6)); if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) tp->t_flags2 |= TF2_PLPMTU_PMTUD; else tp->t_flags2 &= ~TF2_PLPMTU_PMTUD; if (tp->t_state == TCPS_SYN_SENT) TCP_PROBE5(connect__request, NULL, tp, ip6, tp, th); TCP_PROBE5(send, NULL, tp, ip6, tp, th); /* TODO: IPv6 IP6TOS_ECT bit on */ error = ip6_output(m, tp->t_inpcb->in6p_outputopts, &inp->inp_route6, ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0), NULL, NULL, inp); if (error == EMSGSIZE && inp->inp_route6.ro_rt != NULL) mtu = inp->inp_route6.ro_rt->rt_mtu; } #endif /* INET6 */ #if defined(INET) && defined(INET6) else #endif #ifdef INET { ip->ip_len = htons(m->m_pkthdr.len); #ifdef INET6 if (inp->inp_vflag & INP_IPV6PROTO) ip->ip_ttl = in6_selecthlim(inp, NULL); #endif /* INET6 */ /* * If we do path MTU discovery, then we set DF on every * packet. This might not be the best thing to do according * to RFC3390 Section 2. However the tcp hostcache migitates * the problem so it affects only the first tcp connection * with a host. * * NB: Don't set DF on small MTU/MSS to have a safe * fallback. */ if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) { tp->t_flags2 |= TF2_PLPMTU_PMTUD; if (tp->t_port == 0 || len < V_tcp_minmss) { ip->ip_off |= htons(IP_DF); } } else { tp->t_flags2 &= ~TF2_PLPMTU_PMTUD; } if (tp->t_state == TCPS_SYN_SENT) TCP_PROBE5(connect__request, NULL, tp, ip, tp, th); TCP_PROBE5(send, NULL, tp, ip, tp, th); error = ip_output(m, tp->t_inpcb->inp_options, &inp->inp_route, ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0), 0, inp); if (error == EMSGSIZE && inp->inp_route.ro_rt != NULL) mtu = inp->inp_route.ro_rt->rt_mtu; } #endif /* INET */ out: if (lgb) { lgb->tlb_errno = error; lgb = NULL; } /* * In transmit state, time the transmission and arrange for the * retransmit. In persist state, just set snd_max. */ if (error == 0) { if (len == 0) counter_u64_add(rack_out_size[TCP_MSS_ACCT_SNDACK], 1); else if (len == 1) { counter_u64_add(rack_out_size[TCP_MSS_ACCT_PERSIST], 1); } else if (len > 1) { int idx; idx = (len / tp->t_maxseg) + 3; if (idx >= TCP_MSS_ACCT_ATIMER) counter_u64_add(rack_out_size[(TCP_MSS_ACCT_ATIMER-1)], 1); else counter_u64_add(rack_out_size[idx], 1); } } if (sub_from_prr && (error == 0)) { rack->r_ctl.rc_prr_sndcnt -= len; } sub_from_prr = 0; rack_log_output(tp, &to, len, rack_seq, (uint8_t) flags, error, cts, pass, rsm); if ((tp->t_flags & TF_FORCEDATA) == 0 || (rack->rc_in_persist == 0)) { tcp_seq startseq = tp->snd_nxt; /* * Advance snd_nxt over sequence space of this segment. */ if (error) /* We don't log or do anything with errors */ goto timer; if (flags & (TH_SYN | TH_FIN)) { if (flags & TH_SYN) tp->snd_nxt++; if (flags & TH_FIN) { tp->snd_nxt++; tp->t_flags |= TF_SENTFIN; } } /* In the ENOBUFS case we do *not* update snd_max */ if (sack_rxmit) goto timer; tp->snd_nxt += len; if (SEQ_GT(tp->snd_nxt, tp->snd_max)) { if (tp->snd_una == tp->snd_max) { /* * Update the time we just added data since * none was outstanding. */ rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__); tp->t_acktime = ticks; } tp->snd_max = tp->snd_nxt; /* * Time this transmission if not a retransmission and * not currently timing anything. * This is only relevant in case of switching back to * the base stack. */ if (tp->t_rtttime == 0) { tp->t_rtttime = ticks; tp->t_rtseq = startseq; TCPSTAT_INC(tcps_segstimed); } #ifdef NETFLIX_STATS if (!(tp->t_flags & TF_GPUTINPROG) && len) { tp->t_flags |= TF_GPUTINPROG; tp->gput_seq = startseq; tp->gput_ack = startseq + ulmin(sbavail(sb) - sb_offset, sendwin); tp->gput_ts = tcp_ts_getticks(); } #endif } /* * Set retransmit timer if not currently set, and not doing * a pure ack or a keep-alive probe. Initial value for * retransmit timer is smoothed round-trip time + 2 * * round-trip time variance. Initialize shift counter which * is used for backoff of retransmit time. */ timer: if ((tp->snd_wnd == 0) && TCPS_HAVEESTABLISHED(tp->t_state)) { /* * If the persists timer was set above (right before * the goto send), and still needs to be on. Lets * make sure all is canceled. If the persist timer * is not running, we want to get it up. */ if (rack->rc_in_persist == 0) { rack_enter_persist(tp, rack, cts); } } } else { /* * Persist case, update snd_max but since we are in persist * mode (no window) we do not update snd_nxt. */ int32_t xlen = len; if (error) goto nomore; if (flags & TH_SYN) ++xlen; if (flags & TH_FIN) { ++xlen; tp->t_flags |= TF_SENTFIN; } /* In the ENOBUFS case we do *not* update snd_max */ if (SEQ_GT(tp->snd_nxt + xlen, tp->snd_max)) { if (tp->snd_una == tp->snd_max) { /* * Update the time we just added data since * none was outstanding. */ rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__); tp->t_acktime = ticks; } tp->snd_max = tp->snd_nxt + len; } } nomore: if (error) { SOCKBUF_UNLOCK_ASSERT(sb); /* Check gotos. */ /* * Failures do not advance the seq counter above. For the * case of ENOBUFS we will fall out and retry in 1ms with * the hpts. Everything else will just have to retransmit * with the timer. * * In any case, we do not want to loop around for another * send without a good reason. */ sendalot = 0; switch (error) { case EPERM: tp->t_flags &= ~TF_FORCEDATA; tp->t_softerror = error; return (error); case ENOBUFS: if (slot == 0) { /* * Pace us right away to retry in a some * time */ slot = 1 + rack->rc_enobuf; if (rack->rc_enobuf < 255) rack->rc_enobuf++; if (slot > (rack->rc_rack_rtt / 2)) { slot = rack->rc_rack_rtt / 2; } if (slot < 10) slot = 10; } counter_u64_add(rack_saw_enobuf, 1); error = 0; goto enobufs; case EMSGSIZE: /* * For some reason the interface we used initially * to send segments changed to another or lowered * its MTU. If TSO was active we either got an * interface without TSO capabilits or TSO was * turned off. If we obtained mtu from ip_output() * then update it and try again. */ if (tso) tp->t_flags &= ~TF_TSO; if (mtu != 0) { tcp_mss_update(tp, -1, mtu, NULL, NULL); goto again; } slot = 10; rack_start_hpts_timer(rack, tp, cts, __LINE__, slot, 0, 1); tp->t_flags &= ~TF_FORCEDATA; return (error); case ENETUNREACH: counter_u64_add(rack_saw_enetunreach, 1); case EHOSTDOWN: case EHOSTUNREACH: case ENETDOWN: if (TCPS_HAVERCVDSYN(tp->t_state)) { tp->t_softerror = error; } /* FALLTHROUGH */ default: slot = 10; rack_start_hpts_timer(rack, tp, cts, __LINE__, slot, 0, 1); tp->t_flags &= ~TF_FORCEDATA; return (error); } } else { rack->rc_enobuf = 0; } TCPSTAT_INC(tcps_sndtotal); /* * Data sent (as far as we can tell). If this advertises a larger * window than any other segment, then remember the size of the * advertised window. Any pending ACK has now been sent. */ if (recwin > 0 && SEQ_GT(tp->rcv_nxt + recwin, tp->rcv_adv)) tp->rcv_adv = tp->rcv_nxt + recwin; tp->last_ack_sent = tp->rcv_nxt; tp->t_flags &= ~(TF_ACKNOW | TF_DELACK); enobufs: rack->r_tlp_running = 0; if ((flags & TH_RST) || (would_have_fin == 1)) { /* * We don't send again after a RST. We also do *not* send * again if we would have had a find, but now have * outstanding data. */ slot = 0; sendalot = 0; } if (slot) { /* set the rack tcb into the slot N */ counter_u64_add(rack_paced_segments, 1); } else if (sendalot) { if (len) counter_u64_add(rack_unpaced_segments, 1); sack_rxmit = 0; tp->t_flags &= ~TF_FORCEDATA; goto again; } else if (len) { counter_u64_add(rack_unpaced_segments, 1); } tp->t_flags &= ~TF_FORCEDATA; rack_start_hpts_timer(rack, tp, cts, __LINE__, slot, tot_len_this_send, 1); return (error); } /* * rack_ctloutput() must drop the inpcb lock before performing copyin on * socket option arguments. When it re-acquires the lock after the copy, it * has to revalidate that the connection is still valid for the socket * option. */ static int rack_set_sockopt(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack) { int32_t error = 0, optval; switch (sopt->sopt_name) { case TCP_RACK_PROP_RATE: case TCP_RACK_PROP: case TCP_RACK_TLP_REDUCE: case TCP_RACK_EARLY_RECOV: case TCP_RACK_PACE_ALWAYS: case TCP_DELACK: case TCP_RACK_PACE_REDUCE: case TCP_RACK_PACE_MAX_SEG: case TCP_RACK_PRR_SENDALOT: case TCP_RACK_MIN_TO: case TCP_RACK_EARLY_SEG: case TCP_RACK_REORD_THRESH: case TCP_RACK_REORD_FADE: case TCP_RACK_TLP_THRESH: case TCP_RACK_PKT_DELAY: case TCP_RACK_TLP_USE: case TCP_RACK_TLP_INC_VAR: case TCP_RACK_IDLE_REDUCE_HIGH: case TCP_RACK_MIN_PACE: case TCP_RACK_MIN_PACE_SEG: case TCP_BBR_RACK_RTT_USE: case TCP_DATA_AFTER_CLOSE: break; default: return (tcp_default_ctloutput(so, sopt, inp, tp)); break; } INP_WUNLOCK(inp); error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval)); if (error) return (error); INP_WLOCK(inp); if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) { INP_WUNLOCK(inp); return (ECONNRESET); } tp = intotcpcb(inp); rack = (struct tcp_rack *)tp->t_fb_ptr; switch (sopt->sopt_name) { case TCP_RACK_PROP_RATE: if ((optval <= 0) || (optval >= 100)) { error = EINVAL; break; } RACK_OPTS_INC(tcp_rack_prop_rate); rack->r_ctl.rc_prop_rate = optval; break; case TCP_RACK_TLP_USE: if ((optval < TLP_USE_ID) || (optval > TLP_USE_TWO_TWO)) { error = EINVAL; break; } RACK_OPTS_INC(tcp_tlp_use); rack->rack_tlp_threshold_use = optval; break; case TCP_RACK_PROP: /* RACK proportional rate reduction (bool) */ RACK_OPTS_INC(tcp_rack_prop); rack->r_ctl.rc_prop_reduce = optval; break; case TCP_RACK_TLP_REDUCE: /* RACK TLP cwnd reduction (bool) */ RACK_OPTS_INC(tcp_rack_tlp_reduce); rack->r_ctl.rc_tlp_cwnd_reduce = optval; break; case TCP_RACK_EARLY_RECOV: /* Should recovery happen early (bool) */ RACK_OPTS_INC(tcp_rack_early_recov); rack->r_ctl.rc_early_recovery = optval; break; case TCP_RACK_PACE_ALWAYS: /* Use the always pace method (bool) */ RACK_OPTS_INC(tcp_rack_pace_always); if (optval > 0) rack->rc_always_pace = 1; else rack->rc_always_pace = 0; break; case TCP_RACK_PACE_REDUCE: /* RACK Hptsi reduction factor (divisor) */ RACK_OPTS_INC(tcp_rack_pace_reduce); if (optval) /* Must be non-zero */ rack->rc_pace_reduce = optval; else error = EINVAL; break; case TCP_RACK_PACE_MAX_SEG: /* Max segments in a pace */ RACK_OPTS_INC(tcp_rack_max_seg); rack->rc_pace_max_segs = optval; break; case TCP_RACK_PRR_SENDALOT: /* Allow PRR to send more than one seg */ RACK_OPTS_INC(tcp_rack_prr_sendalot); rack->r_ctl.rc_prr_sendalot = optval; break; case TCP_RACK_MIN_TO: /* Minimum time between rack t-o's in ms */ RACK_OPTS_INC(tcp_rack_min_to); rack->r_ctl.rc_min_to = optval; break; case TCP_RACK_EARLY_SEG: /* If early recovery max segments */ RACK_OPTS_INC(tcp_rack_early_seg); rack->r_ctl.rc_early_recovery_segs = optval; break; case TCP_RACK_REORD_THRESH: /* RACK reorder threshold (shift amount) */ RACK_OPTS_INC(tcp_rack_reord_thresh); if ((optval > 0) && (optval < 31)) rack->r_ctl.rc_reorder_shift = optval; else error = EINVAL; break; case TCP_RACK_REORD_FADE: /* Does reordering fade after ms time */ RACK_OPTS_INC(tcp_rack_reord_fade); rack->r_ctl.rc_reorder_fade = optval; break; case TCP_RACK_TLP_THRESH: /* RACK TLP theshold i.e. srtt+(srtt/N) */ RACK_OPTS_INC(tcp_rack_tlp_thresh); if (optval) rack->r_ctl.rc_tlp_threshold = optval; else error = EINVAL; break; case TCP_RACK_PKT_DELAY: /* RACK added ms i.e. rack-rtt + reord + N */ RACK_OPTS_INC(tcp_rack_pkt_delay); rack->r_ctl.rc_pkt_delay = optval; break; case TCP_RACK_TLP_INC_VAR: /* Does TLP include rtt variance in t-o */ RACK_OPTS_INC(tcp_rack_tlp_inc_var); rack->r_ctl.rc_prr_inc_var = optval; break; case TCP_RACK_IDLE_REDUCE_HIGH: RACK_OPTS_INC(tcp_rack_idle_reduce_high); if (optval) rack->r_idle_reduce_largest = 1; else rack->r_idle_reduce_largest = 0; break; case TCP_DELACK: if (optval == 0) tp->t_delayed_ack = 0; else tp->t_delayed_ack = 1; if (tp->t_flags & TF_DELACK) { tp->t_flags &= ~TF_DELACK; tp->t_flags |= TF_ACKNOW; rack_output(tp); } break; case TCP_RACK_MIN_PACE: RACK_OPTS_INC(tcp_rack_min_pace); if (optval > 3) rack->r_enforce_min_pace = 3; else rack->r_enforce_min_pace = optval; break; case TCP_RACK_MIN_PACE_SEG: RACK_OPTS_INC(tcp_rack_min_pace_seg); if (optval >= 16) rack->r_min_pace_seg_thresh = 15; else rack->r_min_pace_seg_thresh = optval; break; case TCP_BBR_RACK_RTT_USE: if ((optval != USE_RTT_HIGH) && (optval != USE_RTT_LOW) && (optval != USE_RTT_AVG)) error = EINVAL; else rack->r_ctl.rc_rate_sample_method = optval; break; case TCP_DATA_AFTER_CLOSE: if (optval) rack->rc_allow_data_af_clo = 1; else rack->rc_allow_data_af_clo = 0; break; default: return (tcp_default_ctloutput(so, sopt, inp, tp)); break; } #ifdef NETFLIX_STATS tcp_log_socket_option(tp, sopt->sopt_name, optval, error); #endif INP_WUNLOCK(inp); return (error); } static int rack_get_sockopt(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack) { int32_t error, optval; /* * Because all our options are either boolean or an int, we can just * pull everything into optval and then unlock and copy. If we ever * add a option that is not a int, then this will have quite an * impact to this routine. */ switch (sopt->sopt_name) { case TCP_RACK_PROP_RATE: optval = rack->r_ctl.rc_prop_rate; break; case TCP_RACK_PROP: /* RACK proportional rate reduction (bool) */ optval = rack->r_ctl.rc_prop_reduce; break; case TCP_RACK_TLP_REDUCE: /* RACK TLP cwnd reduction (bool) */ optval = rack->r_ctl.rc_tlp_cwnd_reduce; break; case TCP_RACK_EARLY_RECOV: /* Should recovery happen early (bool) */ optval = rack->r_ctl.rc_early_recovery; break; case TCP_RACK_PACE_REDUCE: /* RACK Hptsi reduction factor (divisor) */ optval = rack->rc_pace_reduce; break; case TCP_RACK_PACE_MAX_SEG: /* Max segments in a pace */ optval = rack->rc_pace_max_segs; break; case TCP_RACK_PACE_ALWAYS: /* Use the always pace method */ optval = rack->rc_always_pace; break; case TCP_RACK_PRR_SENDALOT: /* Allow PRR to send more than one seg */ optval = rack->r_ctl.rc_prr_sendalot; break; case TCP_RACK_MIN_TO: /* Minimum time between rack t-o's in ms */ optval = rack->r_ctl.rc_min_to; break; case TCP_RACK_EARLY_SEG: /* If early recovery max segments */ optval = rack->r_ctl.rc_early_recovery_segs; break; case TCP_RACK_REORD_THRESH: /* RACK reorder threshold (shift amount) */ optval = rack->r_ctl.rc_reorder_shift; break; case TCP_RACK_REORD_FADE: /* Does reordering fade after ms time */ optval = rack->r_ctl.rc_reorder_fade; break; case TCP_RACK_TLP_THRESH: /* RACK TLP theshold i.e. srtt+(srtt/N) */ optval = rack->r_ctl.rc_tlp_threshold; break; case TCP_RACK_PKT_DELAY: /* RACK added ms i.e. rack-rtt + reord + N */ optval = rack->r_ctl.rc_pkt_delay; break; case TCP_RACK_TLP_USE: optval = rack->rack_tlp_threshold_use; break; case TCP_RACK_TLP_INC_VAR: /* Does TLP include rtt variance in t-o */ optval = rack->r_ctl.rc_prr_inc_var; break; case TCP_RACK_IDLE_REDUCE_HIGH: optval = rack->r_idle_reduce_largest; break; case TCP_RACK_MIN_PACE: optval = rack->r_enforce_min_pace; break; case TCP_RACK_MIN_PACE_SEG: optval = rack->r_min_pace_seg_thresh; break; case TCP_BBR_RACK_RTT_USE: optval = rack->r_ctl.rc_rate_sample_method; break; case TCP_DELACK: optval = tp->t_delayed_ack; break; case TCP_DATA_AFTER_CLOSE: optval = rack->rc_allow_data_af_clo; break; default: return (tcp_default_ctloutput(so, sopt, inp, tp)); break; } INP_WUNLOCK(inp); error = sooptcopyout(sopt, &optval, sizeof optval); return (error); } static int rack_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp) { int32_t error = EINVAL; struct tcp_rack *rack; rack = (struct tcp_rack *)tp->t_fb_ptr; if (rack == NULL) { /* Huh? */ goto out; } if (sopt->sopt_dir == SOPT_SET) { return (rack_set_sockopt(so, sopt, inp, tp, rack)); } else if (sopt->sopt_dir == SOPT_GET) { return (rack_get_sockopt(so, sopt, inp, tp, rack)); } out: INP_WUNLOCK(inp); return (error); } struct tcp_function_block __tcp_rack = { .tfb_tcp_block_name = __XSTRING(STACKNAME), .tfb_tcp_output = rack_output, .tfb_tcp_do_segment = rack_do_segment, .tfb_tcp_hpts_do_segment = rack_hpts_do_segment, .tfb_tcp_ctloutput = rack_ctloutput, .tfb_tcp_fb_init = rack_init, .tfb_tcp_fb_fini = rack_fini, .tfb_tcp_timer_stop_all = rack_stopall, .tfb_tcp_timer_activate = rack_timer_activate, .tfb_tcp_timer_active = rack_timer_active, .tfb_tcp_timer_stop = rack_timer_stop, .tfb_tcp_rexmit_tmr = rack_remxt_tmr, .tfb_tcp_handoff_ok = rack_handoff_ok }; static const char *rack_stack_names[] = { __XSTRING(STACKNAME), #ifdef STACKALIAS __XSTRING(STACKALIAS), #endif }; static int rack_ctor(void *mem, int32_t size, void *arg, int32_t how) { memset(mem, 0, size); return (0); } static void rack_dtor(void *mem, int32_t size, void *arg) { } static bool rack_mod_inited = false; static int tcp_addrack(module_t mod, int32_t type, void *data) { int32_t err = 0; int num_stacks; switch (type) { case MOD_LOAD: rack_zone = uma_zcreate(__XSTRING(MODNAME) "_map", sizeof(struct rack_sendmap), rack_ctor, rack_dtor, NULL, NULL, UMA_ALIGN_PTR, 0); rack_pcb_zone = uma_zcreate(__XSTRING(MODNAME) "_pcb", sizeof(struct tcp_rack), rack_ctor, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0); sysctl_ctx_init(&rack_sysctl_ctx); rack_sysctl_root = SYSCTL_ADD_NODE(&rack_sysctl_ctx, SYSCTL_STATIC_CHILDREN(_net_inet_tcp), OID_AUTO, __XSTRING(STACKNAME), CTLFLAG_RW, 0, ""); if (rack_sysctl_root == NULL) { printf("Failed to add sysctl node\n"); err = EFAULT; goto free_uma; } rack_init_sysctls(); num_stacks = nitems(rack_stack_names); err = register_tcp_functions_as_names(&__tcp_rack, M_WAITOK, rack_stack_names, &num_stacks); if (err) { printf("Failed to register %s stack name for " "%s module\n", rack_stack_names[num_stacks], __XSTRING(MODNAME)); sysctl_ctx_free(&rack_sysctl_ctx); free_uma: uma_zdestroy(rack_zone); uma_zdestroy(rack_pcb_zone); rack_counter_destroy(); printf("Failed to register rack module -- err:%d\n", err); return (err); } rack_mod_inited = true; break; case MOD_QUIESCE: err = deregister_tcp_functions(&__tcp_rack, true, false); break; case MOD_UNLOAD: err = deregister_tcp_functions(&__tcp_rack, false, true); if (err == EBUSY) break; if (rack_mod_inited) { uma_zdestroy(rack_zone); uma_zdestroy(rack_pcb_zone); sysctl_ctx_free(&rack_sysctl_ctx); rack_counter_destroy(); rack_mod_inited = false; } err = 0; break; default: return (EOPNOTSUPP); } return (err); } static moduledata_t tcp_rack = { .name = __XSTRING(MODNAME), .evhand = tcp_addrack, .priv = 0 }; MODULE_VERSION(MODNAME, 1); DECLARE_MODULE(MODNAME, tcp_rack, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY); MODULE_DEPEND(MODNAME, tcphpts, 1, 1, 1); Index: head/sys/netinet/tcp_syncache.c =================================================================== --- head/sys/netinet/tcp_syncache.c (revision 344366) +++ head/sys/netinet/tcp_syncache.c (revision 344367) @@ -1,2296 +1,2296 @@ /*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 2001 McAfee, Inc. * Copyright (c) 2006,2013 Andre Oppermann, Internet Business Solutions AG * All rights reserved. * * This software was developed for the FreeBSD Project by Jonathan Lemon * and McAfee Research, the Security Research Division of McAfee, Inc. under * DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the * DARPA CHATS research program. [2001 McAfee, Inc.] * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include "opt_inet.h" #include "opt_inet6.h" #include "opt_ipsec.h" #include "opt_pcbgroup.h" #include #include #include #include #include #include #include #include #include #include #include #include /* for proc0 declaration */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET6 #include #include #include #include #include #endif #include #include #include #include #include #include #include #ifdef INET6 #include #endif #ifdef TCP_OFFLOAD #include #endif #include #include #include VNET_DEFINE_STATIC(int, tcp_syncookies) = 1; #define V_tcp_syncookies VNET(tcp_syncookies) SYSCTL_INT(_net_inet_tcp, OID_AUTO, syncookies, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(tcp_syncookies), 0, "Use TCP SYN cookies if the syncache overflows"); VNET_DEFINE_STATIC(int, tcp_syncookiesonly) = 0; #define V_tcp_syncookiesonly VNET(tcp_syncookiesonly) SYSCTL_INT(_net_inet_tcp, OID_AUTO, syncookies_only, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(tcp_syncookiesonly), 0, "Use only TCP SYN cookies"); VNET_DEFINE_STATIC(int, functions_inherit_listen_socket_stack) = 1; #define V_functions_inherit_listen_socket_stack \ VNET(functions_inherit_listen_socket_stack) SYSCTL_INT(_net_inet_tcp, OID_AUTO, functions_inherit_listen_socket_stack, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(functions_inherit_listen_socket_stack), 0, "Inherit listen socket's stack"); #ifdef TCP_OFFLOAD #define ADDED_BY_TOE(sc) ((sc)->sc_tod != NULL) #endif static void syncache_drop(struct syncache *, struct syncache_head *); static void syncache_free(struct syncache *); static void syncache_insert(struct syncache *, struct syncache_head *); static int syncache_respond(struct syncache *, struct syncache_head *, const struct mbuf *, int); static struct socket *syncache_socket(struct syncache *, struct socket *, struct mbuf *m); static void syncache_timeout(struct syncache *sc, struct syncache_head *sch, int docallout); static void syncache_timer(void *); static uint32_t syncookie_mac(struct in_conninfo *, tcp_seq, uint8_t, uint8_t *, uintptr_t); static tcp_seq syncookie_generate(struct syncache_head *, struct syncache *); static struct syncache *syncookie_lookup(struct in_conninfo *, struct syncache_head *, struct syncache *, struct tcphdr *, struct tcpopt *, struct socket *); static void syncookie_reseed(void *); #ifdef INVARIANTS static int syncookie_cmp(struct in_conninfo *inc, struct syncache_head *sch, struct syncache *sc, struct tcphdr *th, struct tcpopt *to, struct socket *lso); #endif /* * Transmit the SYN,ACK fewer times than TCP_MAXRXTSHIFT specifies. * 3 retransmits corresponds to a timeout with default values of - * TCPTV_RTOBASE * ( 1 + - * tcp_syn_backoff[1] + - * tcp_syn_backoff[2] + - * tcp_syn_backoff[3]) + 3 * tcp_rexmit_slop, - * 3000 ms * (1 + 1 + 1 + 1) + 3 * 200 ms = 12600 ms, + * TCPTV_RTOBASE * ( 1 + + * tcp_backoff[1] + + * tcp_backoff[2] + + * tcp_backoff[3]) + 3 * tcp_rexmit_slop, + * 3000 ms * (1 + 2 + 4 + 8) + 3 * 200 ms = 45600 ms, * the odds are that the user has given up attempting to connect by then. */ #define SYNCACHE_MAXREXMTS 3 /* Arbitrary values */ #define TCP_SYNCACHE_HASHSIZE 512 #define TCP_SYNCACHE_BUCKETLIMIT 30 VNET_DEFINE_STATIC(struct tcp_syncache, tcp_syncache); #define V_tcp_syncache VNET(tcp_syncache) static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, syncache, CTLFLAG_RW, 0, "TCP SYN cache"); SYSCTL_UINT(_net_inet_tcp_syncache, OID_AUTO, bucketlimit, CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_syncache.bucket_limit), 0, "Per-bucket hash limit for syncache"); SYSCTL_UINT(_net_inet_tcp_syncache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_syncache.cache_limit), 0, "Overall entry limit for syncache"); SYSCTL_UMA_CUR(_net_inet_tcp_syncache, OID_AUTO, count, CTLFLAG_VNET, &VNET_NAME(tcp_syncache.zone), "Current number of entries in syncache"); SYSCTL_UINT(_net_inet_tcp_syncache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_syncache.hashsize), 0, "Size of TCP syncache hashtable"); static int sysctl_net_inet_tcp_syncache_rexmtlimit_check(SYSCTL_HANDLER_ARGS) { int error; u_int new; new = V_tcp_syncache.rexmt_limit; error = sysctl_handle_int(oidp, &new, 0, req); if ((error == 0) && (req->newptr != NULL)) { if (new > TCP_MAXRXTSHIFT) error = EINVAL; else V_tcp_syncache.rexmt_limit = new; } return (error); } SYSCTL_PROC(_net_inet_tcp_syncache, OID_AUTO, rexmtlimit, CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, &VNET_NAME(tcp_syncache.rexmt_limit), 0, sysctl_net_inet_tcp_syncache_rexmtlimit_check, "UI", "Limit on SYN/ACK retransmissions"); VNET_DEFINE(int, tcp_sc_rst_sock_fail) = 1; SYSCTL_INT(_net_inet_tcp_syncache, OID_AUTO, rst_on_sock_fail, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(tcp_sc_rst_sock_fail), 0, "Send reset on socket allocation failure"); static MALLOC_DEFINE(M_SYNCACHE, "syncache", "TCP syncache"); #define SCH_LOCK(sch) mtx_lock(&(sch)->sch_mtx) #define SCH_UNLOCK(sch) mtx_unlock(&(sch)->sch_mtx) #define SCH_LOCK_ASSERT(sch) mtx_assert(&(sch)->sch_mtx, MA_OWNED) /* * Requires the syncache entry to be already removed from the bucket list. */ static void syncache_free(struct syncache *sc) { if (sc->sc_ipopts) (void) m_free(sc->sc_ipopts); if (sc->sc_cred) crfree(sc->sc_cred); #ifdef MAC mac_syncache_destroy(&sc->sc_label); #endif uma_zfree(V_tcp_syncache.zone, sc); } void syncache_init(void) { int i; V_tcp_syncache.hashsize = TCP_SYNCACHE_HASHSIZE; V_tcp_syncache.bucket_limit = TCP_SYNCACHE_BUCKETLIMIT; V_tcp_syncache.rexmt_limit = SYNCACHE_MAXREXMTS; V_tcp_syncache.hash_secret = arc4random(); TUNABLE_INT_FETCH("net.inet.tcp.syncache.hashsize", &V_tcp_syncache.hashsize); TUNABLE_INT_FETCH("net.inet.tcp.syncache.bucketlimit", &V_tcp_syncache.bucket_limit); if (!powerof2(V_tcp_syncache.hashsize) || V_tcp_syncache.hashsize == 0) { printf("WARNING: syncache hash size is not a power of 2.\n"); V_tcp_syncache.hashsize = TCP_SYNCACHE_HASHSIZE; } V_tcp_syncache.hashmask = V_tcp_syncache.hashsize - 1; /* Set limits. */ V_tcp_syncache.cache_limit = V_tcp_syncache.hashsize * V_tcp_syncache.bucket_limit; TUNABLE_INT_FETCH("net.inet.tcp.syncache.cachelimit", &V_tcp_syncache.cache_limit); /* Allocate the hash table. */ V_tcp_syncache.hashbase = malloc(V_tcp_syncache.hashsize * sizeof(struct syncache_head), M_SYNCACHE, M_WAITOK | M_ZERO); #ifdef VIMAGE V_tcp_syncache.vnet = curvnet; #endif /* Initialize the hash buckets. */ for (i = 0; i < V_tcp_syncache.hashsize; i++) { TAILQ_INIT(&V_tcp_syncache.hashbase[i].sch_bucket); mtx_init(&V_tcp_syncache.hashbase[i].sch_mtx, "tcp_sc_head", NULL, MTX_DEF); callout_init_mtx(&V_tcp_syncache.hashbase[i].sch_timer, &V_tcp_syncache.hashbase[i].sch_mtx, 0); V_tcp_syncache.hashbase[i].sch_length = 0; V_tcp_syncache.hashbase[i].sch_sc = &V_tcp_syncache; V_tcp_syncache.hashbase[i].sch_last_overflow = -(SYNCOOKIE_LIFETIME + 1); } /* Create the syncache entry zone. */ V_tcp_syncache.zone = uma_zcreate("syncache", sizeof(struct syncache), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); V_tcp_syncache.cache_limit = uma_zone_set_max(V_tcp_syncache.zone, V_tcp_syncache.cache_limit); /* Start the SYN cookie reseeder callout. */ callout_init(&V_tcp_syncache.secret.reseed, 1); arc4rand(V_tcp_syncache.secret.key[0], SYNCOOKIE_SECRET_SIZE, 0); arc4rand(V_tcp_syncache.secret.key[1], SYNCOOKIE_SECRET_SIZE, 0); callout_reset(&V_tcp_syncache.secret.reseed, SYNCOOKIE_LIFETIME * hz, syncookie_reseed, &V_tcp_syncache); } #ifdef VIMAGE void syncache_destroy(void) { struct syncache_head *sch; struct syncache *sc, *nsc; int i; /* * Stop the re-seed timer before freeing resources. No need to * possibly schedule it another time. */ callout_drain(&V_tcp_syncache.secret.reseed); /* Cleanup hash buckets: stop timers, free entries, destroy locks. */ for (i = 0; i < V_tcp_syncache.hashsize; i++) { sch = &V_tcp_syncache.hashbase[i]; callout_drain(&sch->sch_timer); SCH_LOCK(sch); TAILQ_FOREACH_SAFE(sc, &sch->sch_bucket, sc_hash, nsc) syncache_drop(sc, sch); SCH_UNLOCK(sch); KASSERT(TAILQ_EMPTY(&sch->sch_bucket), ("%s: sch->sch_bucket not empty", __func__)); KASSERT(sch->sch_length == 0, ("%s: sch->sch_length %d not 0", __func__, sch->sch_length)); mtx_destroy(&sch->sch_mtx); } KASSERT(uma_zone_get_cur(V_tcp_syncache.zone) == 0, ("%s: cache_count not 0", __func__)); /* Free the allocated global resources. */ uma_zdestroy(V_tcp_syncache.zone); free(V_tcp_syncache.hashbase, M_SYNCACHE); } #endif /* * Inserts a syncache entry into the specified bucket row. * Locks and unlocks the syncache_head autonomously. */ static void syncache_insert(struct syncache *sc, struct syncache_head *sch) { struct syncache *sc2; SCH_LOCK(sch); /* * Make sure that we don't overflow the per-bucket limit. * If the bucket is full, toss the oldest element. */ if (sch->sch_length >= V_tcp_syncache.bucket_limit) { KASSERT(!TAILQ_EMPTY(&sch->sch_bucket), ("sch->sch_length incorrect")); sc2 = TAILQ_LAST(&sch->sch_bucket, sch_head); sch->sch_last_overflow = time_uptime; syncache_drop(sc2, sch); TCPSTAT_INC(tcps_sc_bucketoverflow); } /* Put it into the bucket. */ TAILQ_INSERT_HEAD(&sch->sch_bucket, sc, sc_hash); sch->sch_length++; #ifdef TCP_OFFLOAD if (ADDED_BY_TOE(sc)) { struct toedev *tod = sc->sc_tod; tod->tod_syncache_added(tod, sc->sc_todctx); } #endif /* Reinitialize the bucket row's timer. */ if (sch->sch_length == 1) sch->sch_nextc = ticks + INT_MAX; syncache_timeout(sc, sch, 1); SCH_UNLOCK(sch); TCPSTATES_INC(TCPS_SYN_RECEIVED); TCPSTAT_INC(tcps_sc_added); } /* * Remove and free entry from syncache bucket row. * Expects locked syncache head. */ static void syncache_drop(struct syncache *sc, struct syncache_head *sch) { SCH_LOCK_ASSERT(sch); TCPSTATES_DEC(TCPS_SYN_RECEIVED); TAILQ_REMOVE(&sch->sch_bucket, sc, sc_hash); sch->sch_length--; #ifdef TCP_OFFLOAD if (ADDED_BY_TOE(sc)) { struct toedev *tod = sc->sc_tod; tod->tod_syncache_removed(tod, sc->sc_todctx); } #endif syncache_free(sc); } /* * Engage/reengage time on bucket row. */ static void syncache_timeout(struct syncache *sc, struct syncache_head *sch, int docallout) { int rexmt; if (sc->sc_rxmits == 0) rexmt = TCPTV_RTOBASE; else - TCPT_RANGESET(rexmt, TCPTV_RTOBASE * tcp_syn_backoff[sc->sc_rxmits], + TCPT_RANGESET(rexmt, TCPTV_RTOBASE * tcp_backoff[sc->sc_rxmits], tcp_rexmit_min, TCPTV_REXMTMAX); sc->sc_rxttime = ticks + rexmt; sc->sc_rxmits++; if (TSTMP_LT(sc->sc_rxttime, sch->sch_nextc)) { sch->sch_nextc = sc->sc_rxttime; if (docallout) callout_reset(&sch->sch_timer, sch->sch_nextc - ticks, syncache_timer, (void *)sch); } } /* * Walk the timer queues, looking for SYN,ACKs that need to be retransmitted. * If we have retransmitted an entry the maximum number of times, expire it. * One separate timer for each bucket row. */ static void syncache_timer(void *xsch) { struct syncache_head *sch = (struct syncache_head *)xsch; struct syncache *sc, *nsc; int tick = ticks; char *s; CURVNET_SET(sch->sch_sc->vnet); /* NB: syncache_head has already been locked by the callout. */ SCH_LOCK_ASSERT(sch); /* * In the following cycle we may remove some entries and/or * advance some timeouts, so re-initialize the bucket timer. */ sch->sch_nextc = tick + INT_MAX; TAILQ_FOREACH_SAFE(sc, &sch->sch_bucket, sc_hash, nsc) { /* * We do not check if the listen socket still exists * and accept the case where the listen socket may be * gone by the time we resend the SYN/ACK. We do * not expect this to happens often. If it does, * then the RST will be sent by the time the remote * host does the SYN/ACK->ACK. */ if (TSTMP_GT(sc->sc_rxttime, tick)) { if (TSTMP_LT(sc->sc_rxttime, sch->sch_nextc)) sch->sch_nextc = sc->sc_rxttime; continue; } if (sc->sc_rxmits > V_tcp_syncache.rexmt_limit) { if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: Retransmits exhausted, " "giving up and removing syncache entry\n", s, __func__); free(s, M_TCPLOG); } syncache_drop(sc, sch); TCPSTAT_INC(tcps_sc_stale); continue; } if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: Response timeout, " "retransmitting (%u) SYN|ACK\n", s, __func__, sc->sc_rxmits); free(s, M_TCPLOG); } syncache_respond(sc, sch, NULL, TH_SYN|TH_ACK); TCPSTAT_INC(tcps_sc_retransmitted); syncache_timeout(sc, sch, 0); } if (!TAILQ_EMPTY(&(sch)->sch_bucket)) callout_reset(&(sch)->sch_timer, (sch)->sch_nextc - tick, syncache_timer, (void *)(sch)); CURVNET_RESTORE(); } /* * Find an entry in the syncache. * Returns always with locked syncache_head plus a matching entry or NULL. */ static struct syncache * syncache_lookup(struct in_conninfo *inc, struct syncache_head **schp) { struct syncache *sc; struct syncache_head *sch; uint32_t hash; /* * The hash is built on foreign port + local port + foreign address. * We rely on the fact that struct in_conninfo starts with 16 bits * of foreign port, then 16 bits of local port then followed by 128 * bits of foreign address. In case of IPv4 address, the first 3 * 32-bit words of the address always are zeroes. */ hash = jenkins_hash32((uint32_t *)&inc->inc_ie, 5, V_tcp_syncache.hash_secret) & V_tcp_syncache.hashmask; sch = &V_tcp_syncache.hashbase[hash]; *schp = sch; SCH_LOCK(sch); /* Circle through bucket row to find matching entry. */ TAILQ_FOREACH(sc, &sch->sch_bucket, sc_hash) if (bcmp(&inc->inc_ie, &sc->sc_inc.inc_ie, sizeof(struct in_endpoints)) == 0) break; return (sc); /* Always returns with locked sch. */ } /* * This function is called when we get a RST for a * non-existent connection, so that we can see if the * connection is in the syn cache. If it is, zap it. * If required send a challenge ACK. */ void syncache_chkrst(struct in_conninfo *inc, struct tcphdr *th, struct mbuf *m) { struct syncache *sc; struct syncache_head *sch; char *s = NULL; sc = syncache_lookup(inc, &sch); /* returns locked sch */ SCH_LOCK_ASSERT(sch); /* * Any RST to our SYN|ACK must not carry ACK, SYN or FIN flags. * See RFC 793 page 65, section SEGMENT ARRIVES. */ if (th->th_flags & (TH_ACK|TH_SYN|TH_FIN)) { if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: Spurious RST with ACK, SYN or " "FIN flag set, segment ignored\n", s, __func__); TCPSTAT_INC(tcps_badrst); goto done; } /* * No corresponding connection was found in syncache. * If syncookies are enabled and possibly exclusively * used, or we are under memory pressure, a valid RST * may not find a syncache entry. In that case we're * done and no SYN|ACK retransmissions will happen. * Otherwise the RST was misdirected or spoofed. */ if (sc == NULL) { if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: Spurious RST without matching " "syncache entry (possibly syncookie only), " "segment ignored\n", s, __func__); TCPSTAT_INC(tcps_badrst); goto done; } /* * If the RST bit is set, check the sequence number to see * if this is a valid reset segment. * * RFC 793 page 37: * In all states except SYN-SENT, all reset (RST) segments * are validated by checking their SEQ-fields. A reset is * valid if its sequence number is in the window. * * RFC 793 page 69: * There are four cases for the acceptability test for an incoming * segment: * * Segment Receive Test * Length Window * ------- ------- ------------------------------------------- * 0 0 SEG.SEQ = RCV.NXT * 0 >0 RCV.NXT =< SEG.SEQ < RCV.NXT+RCV.WND * >0 0 not acceptable * >0 >0 RCV.NXT =< SEG.SEQ < RCV.NXT+RCV.WND * or RCV.NXT =< SEG.SEQ+SEG.LEN-1 < RCV.NXT+RCV.WND * * Note that when receiving a SYN segment in the LISTEN state, * IRS is set to SEG.SEQ and RCV.NXT is set to SEG.SEQ+1, as * described in RFC 793, page 66. */ if ((SEQ_GEQ(th->th_seq, sc->sc_irs + 1) && SEQ_LT(th->th_seq, sc->sc_irs + 1 + sc->sc_wnd)) || (sc->sc_wnd == 0 && th->th_seq == sc->sc_irs + 1)) { if (V_tcp_insecure_rst || th->th_seq == sc->sc_irs + 1) { syncache_drop(sc, sch); if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: Our SYN|ACK was rejected, " "connection attempt aborted by remote " "endpoint\n", s, __func__); TCPSTAT_INC(tcps_sc_reset); } else { TCPSTAT_INC(tcps_badrst); /* Send challenge ACK. */ if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: RST with invalid " " SEQ %u != NXT %u (+WND %u), " "sending challenge ACK\n", s, __func__, th->th_seq, sc->sc_irs + 1, sc->sc_wnd); syncache_respond(sc, sch, m, TH_ACK); } } else { if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: RST with invalid SEQ %u != " "NXT %u (+WND %u), segment ignored\n", s, __func__, th->th_seq, sc->sc_irs + 1, sc->sc_wnd); TCPSTAT_INC(tcps_badrst); } done: if (s != NULL) free(s, M_TCPLOG); SCH_UNLOCK(sch); } void syncache_badack(struct in_conninfo *inc) { struct syncache *sc; struct syncache_head *sch; sc = syncache_lookup(inc, &sch); /* returns locked sch */ SCH_LOCK_ASSERT(sch); if (sc != NULL) { syncache_drop(sc, sch); TCPSTAT_INC(tcps_sc_badack); } SCH_UNLOCK(sch); } void syncache_unreach(struct in_conninfo *inc, tcp_seq th_seq) { struct syncache *sc; struct syncache_head *sch; sc = syncache_lookup(inc, &sch); /* returns locked sch */ SCH_LOCK_ASSERT(sch); if (sc == NULL) goto done; /* If the sequence number != sc_iss, then it's a bogus ICMP msg */ if (ntohl(th_seq) != sc->sc_iss) goto done; /* * If we've rertransmitted 3 times and this is our second error, * we remove the entry. Otherwise, we allow it to continue on. * This prevents us from incorrectly nuking an entry during a * spurious network outage. * * See tcp_notify(). */ if ((sc->sc_flags & SCF_UNREACH) == 0 || sc->sc_rxmits < 3 + 1) { sc->sc_flags |= SCF_UNREACH; goto done; } syncache_drop(sc, sch); TCPSTAT_INC(tcps_sc_unreach); done: SCH_UNLOCK(sch); } /* * Build a new TCP socket structure from a syncache entry. * * On success return the newly created socket with its underlying inp locked. */ static struct socket * syncache_socket(struct syncache *sc, struct socket *lso, struct mbuf *m) { struct tcp_function_block *blk; struct inpcb *inp = NULL; struct socket *so; struct tcpcb *tp; int error; char *s; INP_INFO_RLOCK_ASSERT(&V_tcbinfo); /* * Ok, create the full blown connection, and set things up * as they would have been set up if we had created the * connection when the SYN arrived. If we can't create * the connection, abort it. */ so = sonewconn(lso, 0); if (so == NULL) { /* * Drop the connection; we will either send a RST or * have the peer retransmit its SYN again after its * RTO and try again. */ TCPSTAT_INC(tcps_listendrop); if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: Socket create failed " "due to limits or memory shortage\n", s, __func__); free(s, M_TCPLOG); } goto abort2; } #ifdef MAC mac_socketpeer_set_from_mbuf(m, so); #endif inp = sotoinpcb(so); inp->inp_inc.inc_fibnum = so->so_fibnum; INP_WLOCK(inp); /* * Exclusive pcbinfo lock is not required in syncache socket case even * if two inpcb locks can be acquired simultaneously: * - the inpcb in LISTEN state, * - the newly created inp. * * In this case, an inp cannot be at same time in LISTEN state and * just created by an accept() call. */ INP_HASH_WLOCK(&V_tcbinfo); /* Insert new socket into PCB hash list. */ inp->inp_inc.inc_flags = sc->sc_inc.inc_flags; #ifdef INET6 if (sc->sc_inc.inc_flags & INC_ISIPV6) { inp->inp_vflag &= ~INP_IPV4; inp->inp_vflag |= INP_IPV6; inp->in6p_laddr = sc->sc_inc.inc6_laddr; } else { inp->inp_vflag &= ~INP_IPV6; inp->inp_vflag |= INP_IPV4; #endif inp->inp_laddr = sc->sc_inc.inc_laddr; #ifdef INET6 } #endif /* * If there's an mbuf and it has a flowid, then let's initialise the * inp with that particular flowid. */ if (m != NULL && M_HASHTYPE_GET(m) != M_HASHTYPE_NONE) { inp->inp_flowid = m->m_pkthdr.flowid; inp->inp_flowtype = M_HASHTYPE_GET(m); } /* * Install in the reservation hash table for now, but don't yet * install a connection group since the full 4-tuple isn't yet * configured. */ inp->inp_lport = sc->sc_inc.inc_lport; if ((error = in_pcbinshash_nopcbgroup(inp)) != 0) { /* * Undo the assignments above if we failed to * put the PCB on the hash lists. */ #ifdef INET6 if (sc->sc_inc.inc_flags & INC_ISIPV6) inp->in6p_laddr = in6addr_any; else #endif inp->inp_laddr.s_addr = INADDR_ANY; inp->inp_lport = 0; if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: in_pcbinshash failed " "with error %i\n", s, __func__, error); free(s, M_TCPLOG); } INP_HASH_WUNLOCK(&V_tcbinfo); goto abort; } #ifdef INET6 if (inp->inp_vflag & INP_IPV6PROTO) { struct inpcb *oinp = sotoinpcb(lso); /* * Inherit socket options from the listening socket. * Note that in6p_inputopts are not (and should not be) * copied, since it stores previously received options and is * used to detect if each new option is different than the * previous one and hence should be passed to a user. * If we copied in6p_inputopts, a user would not be able to * receive options just after calling the accept system call. */ inp->inp_flags |= oinp->inp_flags & INP_CONTROLOPTS; if (oinp->in6p_outputopts) inp->in6p_outputopts = ip6_copypktopts(oinp->in6p_outputopts, M_NOWAIT); } if (sc->sc_inc.inc_flags & INC_ISIPV6) { struct in6_addr laddr6; struct sockaddr_in6 sin6; sin6.sin6_family = AF_INET6; sin6.sin6_len = sizeof(sin6); sin6.sin6_addr = sc->sc_inc.inc6_faddr; sin6.sin6_port = sc->sc_inc.inc_fport; sin6.sin6_flowinfo = sin6.sin6_scope_id = 0; laddr6 = inp->in6p_laddr; if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) inp->in6p_laddr = sc->sc_inc.inc6_laddr; if ((error = in6_pcbconnect_mbuf(inp, (struct sockaddr *)&sin6, thread0.td_ucred, m)) != 0) { inp->in6p_laddr = laddr6; if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: in6_pcbconnect failed " "with error %i\n", s, __func__, error); free(s, M_TCPLOG); } INP_HASH_WUNLOCK(&V_tcbinfo); goto abort; } /* Override flowlabel from in6_pcbconnect. */ inp->inp_flow &= ~IPV6_FLOWLABEL_MASK; inp->inp_flow |= sc->sc_flowlabel; } #endif /* INET6 */ #if defined(INET) && defined(INET6) else #endif #ifdef INET { struct in_addr laddr; struct sockaddr_in sin; inp->inp_options = (m) ? ip_srcroute(m) : NULL; if (inp->inp_options == NULL) { inp->inp_options = sc->sc_ipopts; sc->sc_ipopts = NULL; } sin.sin_family = AF_INET; sin.sin_len = sizeof(sin); sin.sin_addr = sc->sc_inc.inc_faddr; sin.sin_port = sc->sc_inc.inc_fport; bzero((caddr_t)sin.sin_zero, sizeof(sin.sin_zero)); laddr = inp->inp_laddr; if (inp->inp_laddr.s_addr == INADDR_ANY) inp->inp_laddr = sc->sc_inc.inc_laddr; if ((error = in_pcbconnect_mbuf(inp, (struct sockaddr *)&sin, thread0.td_ucred, m)) != 0) { inp->inp_laddr = laddr; if ((s = tcp_log_addrs(&sc->sc_inc, NULL, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: in_pcbconnect failed " "with error %i\n", s, __func__, error); free(s, M_TCPLOG); } INP_HASH_WUNLOCK(&V_tcbinfo); goto abort; } } #endif /* INET */ #if defined(IPSEC) || defined(IPSEC_SUPPORT) /* Copy old policy into new socket's. */ if (ipsec_copy_pcbpolicy(sotoinpcb(lso), inp) != 0) printf("syncache_socket: could not copy policy\n"); #endif INP_HASH_WUNLOCK(&V_tcbinfo); tp = intotcpcb(inp); tcp_state_change(tp, TCPS_SYN_RECEIVED); tp->iss = sc->sc_iss; tp->irs = sc->sc_irs; tcp_rcvseqinit(tp); tcp_sendseqinit(tp); blk = sototcpcb(lso)->t_fb; if (V_functions_inherit_listen_socket_stack && blk != tp->t_fb) { /* * Our parents t_fb was not the default, * we need to release our ref on tp->t_fb and * pickup one on the new entry. */ struct tcp_function_block *rblk; rblk = find_and_ref_tcp_fb(blk); KASSERT(rblk != NULL, ("cannot find blk %p out of syncache?", blk)); if (tp->t_fb->tfb_tcp_fb_fini) (*tp->t_fb->tfb_tcp_fb_fini)(tp, 0); refcount_release(&tp->t_fb->tfb_refcnt); tp->t_fb = rblk; /* * XXXrrs this is quite dangerous, it is possible * for the new function to fail to init. We also * are not asking if the handoff_is_ok though at * the very start thats probalbly ok. */ if (tp->t_fb->tfb_tcp_fb_init) { (*tp->t_fb->tfb_tcp_fb_init)(tp); } } tp->snd_wl1 = sc->sc_irs; tp->snd_max = tp->iss + 1; tp->snd_nxt = tp->iss + 1; tp->rcv_up = sc->sc_irs + 1; tp->rcv_wnd = sc->sc_wnd; tp->rcv_adv += tp->rcv_wnd; tp->last_ack_sent = tp->rcv_nxt; tp->t_flags = sototcpcb(lso)->t_flags & (TF_NOPUSH|TF_NODELAY); if (sc->sc_flags & SCF_NOOPT) tp->t_flags |= TF_NOOPT; else { if (sc->sc_flags & SCF_WINSCALE) { tp->t_flags |= TF_REQ_SCALE|TF_RCVD_SCALE; tp->snd_scale = sc->sc_requested_s_scale; tp->request_r_scale = sc->sc_requested_r_scale; } if (sc->sc_flags & SCF_TIMESTAMP) { tp->t_flags |= TF_REQ_TSTMP|TF_RCVD_TSTMP; tp->ts_recent = sc->sc_tsreflect; tp->ts_recent_age = tcp_ts_getticks(); tp->ts_offset = sc->sc_tsoff; } #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE) if (sc->sc_flags & SCF_SIGNATURE) tp->t_flags |= TF_SIGNATURE; #endif if (sc->sc_flags & SCF_SACK) tp->t_flags |= TF_SACK_PERMIT; } if (sc->sc_flags & SCF_ECN) tp->t_flags |= TF_ECN_PERMIT; /* * Set up MSS and get cached values from tcp_hostcache. * This might overwrite some of the defaults we just set. */ tcp_mss(tp, sc->sc_peer_mss); /* * If the SYN,ACK was retransmitted, indicate that CWND to be * limited to one segment in cc_conn_init(). * NB: sc_rxmits counts all SYN,ACK transmits, not just retransmits. */ if (sc->sc_rxmits > 1) tp->snd_cwnd = 1; #ifdef TCP_OFFLOAD /* * Allow a TOE driver to install its hooks. Note that we hold the * pcbinfo lock too and that prevents tcp_usr_accept from accepting a * new connection before the TOE driver has done its thing. */ if (ADDED_BY_TOE(sc)) { struct toedev *tod = sc->sc_tod; tod->tod_offload_socket(tod, sc->sc_todctx, so); } #endif /* * Copy and activate timers. */ tp->t_keepinit = sototcpcb(lso)->t_keepinit; tp->t_keepidle = sototcpcb(lso)->t_keepidle; tp->t_keepintvl = sototcpcb(lso)->t_keepintvl; tp->t_keepcnt = sototcpcb(lso)->t_keepcnt; tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp)); TCPSTAT_INC(tcps_accepts); return (so); abort: INP_WUNLOCK(inp); abort2: if (so != NULL) soabort(so); return (NULL); } /* * This function gets called when we receive an ACK for a * socket in the LISTEN state. We look up the connection * in the syncache, and if its there, we pull it out of * the cache and turn it into a full-blown connection in * the SYN-RECEIVED state. * * On syncache_socket() success the newly created socket * has its underlying inp locked. */ int syncache_expand(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th, struct socket **lsop, struct mbuf *m) { struct syncache *sc; struct syncache_head *sch; struct syncache scs; char *s; /* * Global TCP locks are held because we manipulate the PCB lists * and create a new socket. */ INP_INFO_RLOCK_ASSERT(&V_tcbinfo); KASSERT((th->th_flags & (TH_RST|TH_ACK|TH_SYN)) == TH_ACK, ("%s: can handle only ACK", __func__)); sc = syncache_lookup(inc, &sch); /* returns locked sch */ SCH_LOCK_ASSERT(sch); #ifdef INVARIANTS /* * Test code for syncookies comparing the syncache stored * values with the reconstructed values from the cookie. */ if (sc != NULL) syncookie_cmp(inc, sch, sc, th, to, *lsop); #endif if (sc == NULL) { /* * There is no syncache entry, so see if this ACK is * a returning syncookie. To do this, first: * A. Check if syncookies are used in case of syncache * overflows * B. See if this socket has had a syncache entry dropped in * the recent past. We don't want to accept a bogus * syncookie if we've never received a SYN or accept it * twice. * C. check that the syncookie is valid. If it is, then * cobble up a fake syncache entry, and return. */ if (!V_tcp_syncookies) { SCH_UNLOCK(sch); if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: Spurious ACK, " "segment rejected (syncookies disabled)\n", s, __func__); goto failed; } if (!V_tcp_syncookiesonly && sch->sch_last_overflow < time_uptime - SYNCOOKIE_LIFETIME) { SCH_UNLOCK(sch); if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: Spurious ACK, " "segment rejected (no syncache entry)\n", s, __func__); goto failed; } bzero(&scs, sizeof(scs)); sc = syncookie_lookup(inc, sch, &scs, th, to, *lsop); SCH_UNLOCK(sch); if (sc == NULL) { if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: Segment failed " "SYNCOOKIE authentication, segment rejected " "(probably spoofed)\n", s, __func__); goto failed; } #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE) /* If received ACK has MD5 signature, check it. */ if ((to->to_flags & TOF_SIGNATURE) != 0 && (!TCPMD5_ENABLED() || TCPMD5_INPUT(m, th, to->to_signature) != 0)) { /* Drop the ACK. */ if ((s = tcp_log_addrs(inc, th, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: Segment rejected, " "MD5 signature doesn't match.\n", s, __func__); free(s, M_TCPLOG); } TCPSTAT_INC(tcps_sig_err_sigopt); return (-1); /* Do not send RST */ } #endif /* TCP_SIGNATURE */ } else { #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE) /* * If listening socket requested TCP digests, check that * received ACK has signature and it is correct. * If not, drop the ACK and leave sc entry in th cache, * because SYN was received with correct signature. */ if (sc->sc_flags & SCF_SIGNATURE) { if ((to->to_flags & TOF_SIGNATURE) == 0) { /* No signature */ TCPSTAT_INC(tcps_sig_err_nosigopt); SCH_UNLOCK(sch); if ((s = tcp_log_addrs(inc, th, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: Segment " "rejected, MD5 signature wasn't " "provided.\n", s, __func__); free(s, M_TCPLOG); } return (-1); /* Do not send RST */ } if (!TCPMD5_ENABLED() || TCPMD5_INPUT(m, th, to->to_signature) != 0) { /* Doesn't match or no SA */ SCH_UNLOCK(sch); if ((s = tcp_log_addrs(inc, th, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: Segment " "rejected, MD5 signature doesn't " "match.\n", s, __func__); free(s, M_TCPLOG); } return (-1); /* Do not send RST */ } } #endif /* TCP_SIGNATURE */ /* * Pull out the entry to unlock the bucket row. * * NOTE: We must decrease TCPS_SYN_RECEIVED count here, not * tcp_state_change(). The tcpcb is not existent at this * moment. A new one will be allocated via syncache_socket-> * sonewconn->tcp_usr_attach in TCPS_CLOSED state, then * syncache_socket() will change it to TCPS_SYN_RECEIVED. */ TCPSTATES_DEC(TCPS_SYN_RECEIVED); TAILQ_REMOVE(&sch->sch_bucket, sc, sc_hash); sch->sch_length--; #ifdef TCP_OFFLOAD if (ADDED_BY_TOE(sc)) { struct toedev *tod = sc->sc_tod; tod->tod_syncache_removed(tod, sc->sc_todctx); } #endif SCH_UNLOCK(sch); } /* * Segment validation: * ACK must match our initial sequence number + 1 (the SYN|ACK). */ if (th->th_ack != sc->sc_iss + 1) { if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: ACK %u != ISS+1 %u, segment " "rejected\n", s, __func__, th->th_ack, sc->sc_iss); goto failed; } /* * The SEQ must fall in the window starting at the received * initial receive sequence number + 1 (the SYN). */ if (SEQ_LEQ(th->th_seq, sc->sc_irs) || SEQ_GT(th->th_seq, sc->sc_irs + sc->sc_wnd)) { if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: SEQ %u != IRS+1 %u, segment " "rejected\n", s, __func__, th->th_seq, sc->sc_irs); goto failed; } /* * If timestamps were not negotiated during SYN/ACK they * must not appear on any segment during this session. */ if (!(sc->sc_flags & SCF_TIMESTAMP) && (to->to_flags & TOF_TS)) { if ((s = tcp_log_addrs(inc, th, NULL, NULL))) log(LOG_DEBUG, "%s; %s: Timestamp not expected, " "segment rejected\n", s, __func__); goto failed; } /* * If timestamps were negotiated during SYN/ACK they should * appear on every segment during this session. * XXXAO: This is only informal as there have been unverified * reports of non-compliants stacks. */ if ((sc->sc_flags & SCF_TIMESTAMP) && !(to->to_flags & TOF_TS)) { if ((s = tcp_log_addrs(inc, th, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: Timestamp missing, " "no action\n", s, __func__); free(s, M_TCPLOG); s = NULL; } } *lsop = syncache_socket(sc, *lsop, m); if (*lsop == NULL) TCPSTAT_INC(tcps_sc_aborted); else TCPSTAT_INC(tcps_sc_completed); /* how do we find the inp for the new socket? */ if (sc != &scs) syncache_free(sc); return (1); failed: if (sc != NULL && sc != &scs) syncache_free(sc); if (s != NULL) free(s, M_TCPLOG); *lsop = NULL; return (0); } static void syncache_tfo_expand(struct syncache *sc, struct socket **lsop, struct mbuf *m, uint64_t response_cookie) { struct inpcb *inp; struct tcpcb *tp; unsigned int *pending_counter; /* * Global TCP locks are held because we manipulate the PCB lists * and create a new socket. */ INP_INFO_RLOCK_ASSERT(&V_tcbinfo); pending_counter = intotcpcb(sotoinpcb(*lsop))->t_tfo_pending; *lsop = syncache_socket(sc, *lsop, m); if (*lsop == NULL) { TCPSTAT_INC(tcps_sc_aborted); atomic_subtract_int(pending_counter, 1); } else { soisconnected(*lsop); inp = sotoinpcb(*lsop); tp = intotcpcb(inp); tp->t_flags |= TF_FASTOPEN; tp->t_tfo_cookie.server = response_cookie; tp->snd_max = tp->iss; tp->snd_nxt = tp->iss; tp->t_tfo_pending = pending_counter; TCPSTAT_INC(tcps_sc_completed); } } /* * Given a LISTEN socket and an inbound SYN request, add * this to the syn cache, and send back a segment: * * to the source. * * IMPORTANT NOTE: We do _NOT_ ACK data that might accompany the SYN. * Doing so would require that we hold onto the data and deliver it * to the application. However, if we are the target of a SYN-flood * DoS attack, an attacker could send data which would eventually * consume all available buffer space if it were ACKed. By not ACKing * the data, we avoid this DoS scenario. * * The exception to the above is when a SYN with a valid TCP Fast Open (TFO) * cookie is processed and a new socket is created. In this case, any data * accompanying the SYN will be queued to the socket by tcp_input() and will * be ACKed either when the application sends response data or the delayed * ACK timer expires, whichever comes first. */ int syncache_add(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th, struct inpcb *inp, struct socket **lsop, struct mbuf *m, void *tod, void *todctx) { struct tcpcb *tp; struct socket *so; struct syncache *sc = NULL; struct syncache_head *sch; struct mbuf *ipopts = NULL; u_int ltflags; int win, ip_ttl, ip_tos; char *s; int rv = 0; #ifdef INET6 int autoflowlabel = 0; #endif #ifdef MAC struct label *maclabel; #endif struct syncache scs; struct ucred *cred; uint64_t tfo_response_cookie; unsigned int *tfo_pending = NULL; int tfo_cookie_valid = 0; int tfo_response_cookie_valid = 0; INP_WLOCK_ASSERT(inp); /* listen socket */ KASSERT((th->th_flags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN, ("%s: unexpected tcp flags", __func__)); /* * Combine all so/tp operations very early to drop the INP lock as * soon as possible. */ so = *lsop; KASSERT(SOLISTENING(so), ("%s: %p not listening", __func__, so)); tp = sototcpcb(so); cred = crhold(so->so_cred); #ifdef INET6 if ((inc->inc_flags & INC_ISIPV6) && (inp->inp_flags & IN6P_AUTOFLOWLABEL)) autoflowlabel = 1; #endif ip_ttl = inp->inp_ip_ttl; ip_tos = inp->inp_ip_tos; win = so->sol_sbrcv_hiwat; ltflags = (tp->t_flags & (TF_NOOPT | TF_SIGNATURE)); if (V_tcp_fastopen_server_enable && IS_FASTOPEN(tp->t_flags) && (tp->t_tfo_pending != NULL) && (to->to_flags & TOF_FASTOPEN)) { /* * Limit the number of pending TFO connections to * approximately half of the queue limit. This prevents TFO * SYN floods from starving the service by filling the * listen queue with bogus TFO connections. */ if (atomic_fetchadd_int(tp->t_tfo_pending, 1) <= (so->sol_qlimit / 2)) { int result; result = tcp_fastopen_check_cookie(inc, to->to_tfo_cookie, to->to_tfo_len, &tfo_response_cookie); tfo_cookie_valid = (result > 0); tfo_response_cookie_valid = (result >= 0); } /* * Remember the TFO pending counter as it will have to be * decremented below if we don't make it to syncache_tfo_expand(). */ tfo_pending = tp->t_tfo_pending; } /* By the time we drop the lock these should no longer be used. */ so = NULL; tp = NULL; #ifdef MAC if (mac_syncache_init(&maclabel) != 0) { INP_WUNLOCK(inp); goto done; } else mac_syncache_create(maclabel, inp); #endif if (!tfo_cookie_valid) INP_WUNLOCK(inp); /* * Remember the IP options, if any. */ #ifdef INET6 if (!(inc->inc_flags & INC_ISIPV6)) #endif #ifdef INET ipopts = (m) ? ip_srcroute(m) : NULL; #else ipopts = NULL; #endif #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE) /* * If listening socket requested TCP digests, check that received * SYN has signature and it is correct. If signature doesn't match * or TCP_SIGNATURE support isn't enabled, drop the packet. */ if (ltflags & TF_SIGNATURE) { if ((to->to_flags & TOF_SIGNATURE) == 0) { TCPSTAT_INC(tcps_sig_err_nosigopt); goto done; } if (!TCPMD5_ENABLED() || TCPMD5_INPUT(m, th, to->to_signature) != 0) goto done; } #endif /* TCP_SIGNATURE */ /* * See if we already have an entry for this connection. * If we do, resend the SYN,ACK, and reset the retransmit timer. * * XXX: should the syncache be re-initialized with the contents * of the new SYN here (which may have different options?) * * XXX: We do not check the sequence number to see if this is a * real retransmit or a new connection attempt. The question is * how to handle such a case; either ignore it as spoofed, or * drop the current entry and create a new one? */ sc = syncache_lookup(inc, &sch); /* returns locked entry */ SCH_LOCK_ASSERT(sch); if (sc != NULL) { if (tfo_cookie_valid) INP_WUNLOCK(inp); TCPSTAT_INC(tcps_sc_dupsyn); if (ipopts) { /* * If we were remembering a previous source route, * forget it and use the new one we've been given. */ if (sc->sc_ipopts) (void) m_free(sc->sc_ipopts); sc->sc_ipopts = ipopts; } /* * Update timestamp if present. */ if ((sc->sc_flags & SCF_TIMESTAMP) && (to->to_flags & TOF_TS)) sc->sc_tsreflect = to->to_tsval; else sc->sc_flags &= ~SCF_TIMESTAMP; #ifdef MAC /* * Since we have already unconditionally allocated label * storage, free it up. The syncache entry will already * have an initialized label we can use. */ mac_syncache_destroy(&maclabel); #endif TCP_PROBE5(receive, NULL, NULL, m, NULL, th); /* Retransmit SYN|ACK and reset retransmit count. */ if ((s = tcp_log_addrs(&sc->sc_inc, th, NULL, NULL))) { log(LOG_DEBUG, "%s; %s: Received duplicate SYN, " "resetting timer and retransmitting SYN|ACK\n", s, __func__); free(s, M_TCPLOG); } if (syncache_respond(sc, sch, m, TH_SYN|TH_ACK) == 0) { sc->sc_rxmits = 0; syncache_timeout(sc, sch, 1); TCPSTAT_INC(tcps_sndacks); TCPSTAT_INC(tcps_sndtotal); } SCH_UNLOCK(sch); goto donenoprobe; } if (tfo_cookie_valid) { bzero(&scs, sizeof(scs)); sc = &scs; goto skip_alloc; } sc = uma_zalloc(V_tcp_syncache.zone, M_NOWAIT | M_ZERO); if (sc == NULL) { /* * The zone allocator couldn't provide more entries. * Treat this as if the cache was full; drop the oldest * entry and insert the new one. */ TCPSTAT_INC(tcps_sc_zonefail); if ((sc = TAILQ_LAST(&sch->sch_bucket, sch_head)) != NULL) { sch->sch_last_overflow = time_uptime; syncache_drop(sc, sch); } sc = uma_zalloc(V_tcp_syncache.zone, M_NOWAIT | M_ZERO); if (sc == NULL) { if (V_tcp_syncookies) { bzero(&scs, sizeof(scs)); sc = &scs; } else { SCH_UNLOCK(sch); if (ipopts) (void) m_free(ipopts); goto done; } } } skip_alloc: if (!tfo_cookie_valid && tfo_response_cookie_valid) sc->sc_tfo_cookie = &tfo_response_cookie; /* * Fill in the syncache values. */ #ifdef MAC sc->sc_label = maclabel; #endif sc->sc_cred = cred; cred = NULL; sc->sc_ipopts = ipopts; bcopy(inc, &sc->sc_inc, sizeof(struct in_conninfo)); #ifdef INET6 if (!(inc->inc_flags & INC_ISIPV6)) #endif { sc->sc_ip_tos = ip_tos; sc->sc_ip_ttl = ip_ttl; } #ifdef TCP_OFFLOAD sc->sc_tod = tod; sc->sc_todctx = todctx; #endif sc->sc_irs = th->th_seq; sc->sc_iss = arc4random(); sc->sc_flags = 0; sc->sc_flowlabel = 0; /* * Initial receive window: clip sbspace to [0 .. TCP_MAXWIN]. * win was derived from socket earlier in the function. */ win = imax(win, 0); win = imin(win, TCP_MAXWIN); sc->sc_wnd = win; if (V_tcp_do_rfc1323) { /* * A timestamp received in a SYN makes * it ok to send timestamp requests and replies. */ if (to->to_flags & TOF_TS) { sc->sc_tsreflect = to->to_tsval; sc->sc_flags |= SCF_TIMESTAMP; sc->sc_tsoff = tcp_new_ts_offset(inc); } if (to->to_flags & TOF_SCALE) { int wscale = 0; /* * Pick the smallest possible scaling factor that * will still allow us to scale up to sb_max, aka * kern.ipc.maxsockbuf. * * We do this because there are broken firewalls that * will corrupt the window scale option, leading to * the other endpoint believing that our advertised * window is unscaled. At scale factors larger than * 5 the unscaled window will drop below 1500 bytes, * leading to serious problems when traversing these * broken firewalls. * * With the default maxsockbuf of 256K, a scale factor * of 3 will be chosen by this algorithm. Those who * choose a larger maxsockbuf should watch out * for the compatibility problems mentioned above. * * RFC1323: The Window field in a SYN (i.e., a * or ) segment itself is never scaled. */ while (wscale < TCP_MAX_WINSHIFT && (TCP_MAXWIN << wscale) < sb_max) wscale++; sc->sc_requested_r_scale = wscale; sc->sc_requested_s_scale = to->to_wscale; sc->sc_flags |= SCF_WINSCALE; } } #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE) /* * If listening socket requested TCP digests, flag this in the * syncache so that syncache_respond() will do the right thing * with the SYN+ACK. */ if (ltflags & TF_SIGNATURE) sc->sc_flags |= SCF_SIGNATURE; #endif /* TCP_SIGNATURE */ if (to->to_flags & TOF_SACKPERM) sc->sc_flags |= SCF_SACK; if (to->to_flags & TOF_MSS) sc->sc_peer_mss = to->to_mss; /* peer mss may be zero */ if (ltflags & TF_NOOPT) sc->sc_flags |= SCF_NOOPT; if ((th->th_flags & (TH_ECE|TH_CWR)) && V_tcp_do_ecn) sc->sc_flags |= SCF_ECN; if (V_tcp_syncookies) sc->sc_iss = syncookie_generate(sch, sc); #ifdef INET6 if (autoflowlabel) { if (V_tcp_syncookies) sc->sc_flowlabel = sc->sc_iss; else sc->sc_flowlabel = ip6_randomflowlabel(); sc->sc_flowlabel = htonl(sc->sc_flowlabel) & IPV6_FLOWLABEL_MASK; } #endif SCH_UNLOCK(sch); if (tfo_cookie_valid) { syncache_tfo_expand(sc, lsop, m, tfo_response_cookie); /* INP_WUNLOCK(inp) will be performed by the caller */ rv = 1; goto tfo_expanded; } TCP_PROBE5(receive, NULL, NULL, m, NULL, th); /* * Do a standard 3-way handshake. */ if (syncache_respond(sc, sch, m, TH_SYN|TH_ACK) == 0) { if (V_tcp_syncookies && V_tcp_syncookiesonly && sc != &scs) syncache_free(sc); else if (sc != &scs) syncache_insert(sc, sch); /* locks and unlocks sch */ TCPSTAT_INC(tcps_sndacks); TCPSTAT_INC(tcps_sndtotal); } else { if (sc != &scs) syncache_free(sc); TCPSTAT_INC(tcps_sc_dropped); } goto donenoprobe; done: TCP_PROBE5(receive, NULL, NULL, m, NULL, th); donenoprobe: if (m) { *lsop = NULL; m_freem(m); } /* * If tfo_pending is not NULL here, then a TFO SYN that did not * result in a new socket was processed and the associated pending * counter has not yet been decremented. All such TFO processing paths * transit this point. */ if (tfo_pending != NULL) tcp_fastopen_decrement_counter(tfo_pending); tfo_expanded: if (cred != NULL) crfree(cred); #ifdef MAC if (sc == &scs) mac_syncache_destroy(&maclabel); #endif return (rv); } /* * Send SYN|ACK or ACK to the peer. Either in response to a peer's segment, * i.e. m0 != NULL, or upon 3WHS ACK timeout, i.e. m0 == NULL. */ static int syncache_respond(struct syncache *sc, struct syncache_head *sch, const struct mbuf *m0, int flags) { struct ip *ip = NULL; struct mbuf *m; struct tcphdr *th = NULL; int optlen, error = 0; /* Make compiler happy */ u_int16_t hlen, tlen, mssopt; struct tcpopt to; #ifdef INET6 struct ip6_hdr *ip6 = NULL; #endif hlen = #ifdef INET6 (sc->sc_inc.inc_flags & INC_ISIPV6) ? sizeof(struct ip6_hdr) : #endif sizeof(struct ip); tlen = hlen + sizeof(struct tcphdr); /* Determine MSS we advertize to other end of connection. */ mssopt = max(tcp_mssopt(&sc->sc_inc), V_tcp_minmss); /* XXX: Assume that the entire packet will fit in a header mbuf. */ KASSERT(max_linkhdr + tlen + TCP_MAXOLEN <= MHLEN, ("syncache: mbuf too small")); /* Create the IP+TCP header from scratch. */ m = m_gethdr(M_NOWAIT, MT_DATA); if (m == NULL) return (ENOBUFS); #ifdef MAC mac_syncache_create_mbuf(sc->sc_label, m); #endif m->m_data += max_linkhdr; m->m_len = tlen; m->m_pkthdr.len = tlen; m->m_pkthdr.rcvif = NULL; #ifdef INET6 if (sc->sc_inc.inc_flags & INC_ISIPV6) { ip6 = mtod(m, struct ip6_hdr *); ip6->ip6_vfc = IPV6_VERSION; ip6->ip6_nxt = IPPROTO_TCP; ip6->ip6_src = sc->sc_inc.inc6_laddr; ip6->ip6_dst = sc->sc_inc.inc6_faddr; ip6->ip6_plen = htons(tlen - hlen); /* ip6_hlim is set after checksum */ ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK; ip6->ip6_flow |= sc->sc_flowlabel; th = (struct tcphdr *)(ip6 + 1); } #endif #if defined(INET6) && defined(INET) else #endif #ifdef INET { ip = mtod(m, struct ip *); ip->ip_v = IPVERSION; ip->ip_hl = sizeof(struct ip) >> 2; ip->ip_len = htons(tlen); ip->ip_id = 0; ip->ip_off = 0; ip->ip_sum = 0; ip->ip_p = IPPROTO_TCP; ip->ip_src = sc->sc_inc.inc_laddr; ip->ip_dst = sc->sc_inc.inc_faddr; ip->ip_ttl = sc->sc_ip_ttl; ip->ip_tos = sc->sc_ip_tos; /* * See if we should do MTU discovery. Route lookups are * expensive, so we will only unset the DF bit if: * * 1) path_mtu_discovery is disabled * 2) the SCF_UNREACH flag has been set */ if (V_path_mtu_discovery && ((sc->sc_flags & SCF_UNREACH) == 0)) ip->ip_off |= htons(IP_DF); th = (struct tcphdr *)(ip + 1); } #endif /* INET */ th->th_sport = sc->sc_inc.inc_lport; th->th_dport = sc->sc_inc.inc_fport; if (flags & TH_SYN) th->th_seq = htonl(sc->sc_iss); else th->th_seq = htonl(sc->sc_iss + 1); th->th_ack = htonl(sc->sc_irs + 1); th->th_off = sizeof(struct tcphdr) >> 2; th->th_x2 = 0; th->th_flags = flags; th->th_win = htons(sc->sc_wnd); th->th_urp = 0; if ((flags & TH_SYN) && (sc->sc_flags & SCF_ECN)) { th->th_flags |= TH_ECE; TCPSTAT_INC(tcps_ecn_shs); } /* Tack on the TCP options. */ if ((sc->sc_flags & SCF_NOOPT) == 0) { to.to_flags = 0; if (flags & TH_SYN) { to.to_mss = mssopt; to.to_flags = TOF_MSS; if (sc->sc_flags & SCF_WINSCALE) { to.to_wscale = sc->sc_requested_r_scale; to.to_flags |= TOF_SCALE; } if (sc->sc_flags & SCF_SACK) to.to_flags |= TOF_SACKPERM; #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE) if (sc->sc_flags & SCF_SIGNATURE) to.to_flags |= TOF_SIGNATURE; #endif if (sc->sc_tfo_cookie) { to.to_flags |= TOF_FASTOPEN; to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN; to.to_tfo_cookie = sc->sc_tfo_cookie; /* don't send cookie again when retransmitting response */ sc->sc_tfo_cookie = NULL; } } if (sc->sc_flags & SCF_TIMESTAMP) { to.to_tsval = sc->sc_tsoff + tcp_ts_getticks(); to.to_tsecr = sc->sc_tsreflect; to.to_flags |= TOF_TS; } optlen = tcp_addoptions(&to, (u_char *)(th + 1)); /* Adjust headers by option size. */ th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; m->m_len += optlen; m->m_pkthdr.len += optlen; #ifdef INET6 if (sc->sc_inc.inc_flags & INC_ISIPV6) ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) + optlen); else #endif ip->ip_len = htons(ntohs(ip->ip_len) + optlen); #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE) if (sc->sc_flags & SCF_SIGNATURE) { KASSERT(to.to_flags & TOF_SIGNATURE, ("tcp_addoptions() didn't set tcp_signature")); /* NOTE: to.to_signature is inside of mbuf */ if (!TCPMD5_ENABLED() || TCPMD5_OUTPUT(m, th, to.to_signature) != 0) { m_freem(m); return (EACCES); } } #endif } else optlen = 0; M_SETFIB(m, sc->sc_inc.inc_fibnum); m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); /* * If we have peer's SYN and it has a flowid, then let's assign it to * our SYN|ACK. ip6_output() and ip_output() will not assign flowid * to SYN|ACK due to lack of inp here. */ if (m0 != NULL && M_HASHTYPE_GET(m0) != M_HASHTYPE_NONE) { m->m_pkthdr.flowid = m0->m_pkthdr.flowid; M_HASHTYPE_SET(m, M_HASHTYPE_GET(m0)); } #ifdef INET6 if (sc->sc_inc.inc_flags & INC_ISIPV6) { m->m_pkthdr.csum_flags = CSUM_TCP_IPV6; th->th_sum = in6_cksum_pseudo(ip6, tlen + optlen - hlen, IPPROTO_TCP, 0); ip6->ip6_hlim = in6_selecthlim(NULL, NULL); #ifdef TCP_OFFLOAD if (ADDED_BY_TOE(sc)) { struct toedev *tod = sc->sc_tod; error = tod->tod_syncache_respond(tod, sc->sc_todctx, m); return (error); } #endif TCP_PROBE5(send, NULL, NULL, ip6, NULL, th); error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); } #endif #if defined(INET6) && defined(INET) else #endif #ifdef INET { m->m_pkthdr.csum_flags = CSUM_TCP; th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, htons(tlen + optlen - hlen + IPPROTO_TCP)); #ifdef TCP_OFFLOAD if (ADDED_BY_TOE(sc)) { struct toedev *tod = sc->sc_tod; error = tod->tod_syncache_respond(tod, sc->sc_todctx, m); return (error); } #endif TCP_PROBE5(send, NULL, NULL, ip, NULL, th); error = ip_output(m, sc->sc_ipopts, NULL, 0, NULL, NULL); } #endif return (error); } /* * The purpose of syncookies is to handle spoofed SYN flooding DoS attacks * that exceed the capacity of the syncache by avoiding the storage of any * of the SYNs we receive. Syncookies defend against blind SYN flooding * attacks where the attacker does not have access to our responses. * * Syncookies encode and include all necessary information about the * connection setup within the SYN|ACK that we send back. That way we * can avoid keeping any local state until the ACK to our SYN|ACK returns * (if ever). Normally the syncache and syncookies are running in parallel * with the latter taking over when the former is exhausted. When matching * syncache entry is found the syncookie is ignored. * * The only reliable information persisting the 3WHS is our initial sequence * number ISS of 32 bits. Syncookies embed a cryptographically sufficient * strong hash (MAC) value and a few bits of TCP SYN options in the ISS * of our SYN|ACK. The MAC can be recomputed when the ACK to our SYN|ACK * returns and signifies a legitimate connection if it matches the ACK. * * The available space of 32 bits to store the hash and to encode the SYN * option information is very tight and we should have at least 24 bits for * the MAC to keep the number of guesses by blind spoofing reasonably high. * * SYN option information we have to encode to fully restore a connection: * MSS: is imporant to chose an optimal segment size to avoid IP level * fragmentation along the path. The common MSS values can be encoded * in a 3-bit table. Uncommon values are captured by the next lower value * in the table leading to a slight increase in packetization overhead. * WSCALE: is necessary to allow large windows to be used for high delay- * bandwidth product links. Not scaling the window when it was initially * negotiated is bad for performance as lack of scaling further decreases * the apparent available send window. We only need to encode the WSCALE * we received from the remote end. Our end can be recalculated at any * time. The common WSCALE values can be encoded in a 3-bit table. * Uncommon values are captured by the next lower value in the table * making us under-estimate the available window size halving our * theoretically possible maximum throughput for that connection. * SACK: Greatly assists in packet loss recovery and requires 1 bit. * TIMESTAMP and SIGNATURE is not encoded because they are permanent options * that are included in all segments on a connection. We enable them when * the ACK has them. * * Security of syncookies and attack vectors: * * The MAC is computed over (faddr||laddr||fport||lport||irs||flags||secmod) * together with the gloabl secret to make it unique per connection attempt. * Thus any change of any of those parameters results in a different MAC output * in an unpredictable way unless a collision is encountered. 24 bits of the * MAC are embedded into the ISS. * * To prevent replay attacks two rotating global secrets are updated with a * new random value every 15 seconds. The life-time of a syncookie is thus * 15-30 seconds. * * Vector 1: Attacking the secret. This requires finding a weakness in the * MAC itself or the way it is used here. The attacker can do a chosen plain * text attack by varying and testing the all parameters under his control. * The strength depends on the size and randomness of the secret, and the * cryptographic security of the MAC function. Due to the constant updating * of the secret the attacker has at most 29.999 seconds to find the secret * and launch spoofed connections. After that he has to start all over again. * * Vector 2: Collision attack on the MAC of a single ACK. With a 24 bit MAC * size an average of 4,823 attempts are required for a 50% chance of success * to spoof a single syncookie (birthday collision paradox). However the * attacker is blind and doesn't know if one of his attempts succeeded unless * he has a side channel to interfere success from. A single connection setup * success average of 90% requires 8,790 packets, 99.99% requires 17,578 packets. * This many attempts are required for each one blind spoofed connection. For * every additional spoofed connection he has to launch another N attempts. * Thus for a sustained rate 100 spoofed connections per second approximately * 1,800,000 packets per second would have to be sent. * * NB: The MAC function should be fast so that it doesn't become a CPU * exhaustion attack vector itself. * * References: * RFC4987 TCP SYN Flooding Attacks and Common Mitigations * SYN cookies were first proposed by cryptographer Dan J. Bernstein in 1996 * http://cr.yp.to/syncookies.html (overview) * http://cr.yp.to/syncookies/archive (details) * * * Schematic construction of a syncookie enabled Initial Sequence Number: * 0 1 2 3 * 12345678901234567890123456789012 * |xxxxxxxxxxxxxxxxxxxxxxxxWWWMMMSP| * * x 24 MAC (truncated) * W 3 Send Window Scale index * M 3 MSS index * S 1 SACK permitted * P 1 Odd/even secret */ /* * Distribution and probability of certain MSS values. Those in between are * rounded down to the next lower one. * [An Analysis of TCP Maximum Segment Sizes, S. Alcock and R. Nelson, 2011] * .2% .3% 5% 7% 7% 20% 15% 45% */ static int tcp_sc_msstab[] = { 216, 536, 1200, 1360, 1400, 1440, 1452, 1460 }; /* * Distribution and probability of certain WSCALE values. We have to map the * (send) window scale (shift) option with a range of 0-14 from 4 bits into 3 * bits based on prevalence of certain values. Where we don't have an exact * match for are rounded down to the next lower one letting us under-estimate * the true available window. At the moment this would happen only for the * very uncommon values 3, 5 and those above 8 (more than 16MB socket buffer * and window size). The absence of the WSCALE option (no scaling in either * direction) is encoded with index zero. * [WSCALE values histograms, Allman, 2012] * X 10 10 35 5 6 14 10% by host * X 11 4 5 5 18 49 3% by connections */ static int tcp_sc_wstab[] = { 0, 0, 1, 2, 4, 6, 7, 8 }; /* * Compute the MAC for the SYN cookie. SIPHASH-2-4 is chosen for its speed * and good cryptographic properties. */ static uint32_t syncookie_mac(struct in_conninfo *inc, tcp_seq irs, uint8_t flags, uint8_t *secbits, uintptr_t secmod) { SIPHASH_CTX ctx; uint32_t siphash[2]; SipHash24_Init(&ctx); SipHash_SetKey(&ctx, secbits); switch (inc->inc_flags & INC_ISIPV6) { #ifdef INET case 0: SipHash_Update(&ctx, &inc->inc_faddr, sizeof(inc->inc_faddr)); SipHash_Update(&ctx, &inc->inc_laddr, sizeof(inc->inc_laddr)); break; #endif #ifdef INET6 case INC_ISIPV6: SipHash_Update(&ctx, &inc->inc6_faddr, sizeof(inc->inc6_faddr)); SipHash_Update(&ctx, &inc->inc6_laddr, sizeof(inc->inc6_laddr)); break; #endif } SipHash_Update(&ctx, &inc->inc_fport, sizeof(inc->inc_fport)); SipHash_Update(&ctx, &inc->inc_lport, sizeof(inc->inc_lport)); SipHash_Update(&ctx, &irs, sizeof(irs)); SipHash_Update(&ctx, &flags, sizeof(flags)); SipHash_Update(&ctx, &secmod, sizeof(secmod)); SipHash_Final((u_int8_t *)&siphash, &ctx); return (siphash[0] ^ siphash[1]); } static tcp_seq syncookie_generate(struct syncache_head *sch, struct syncache *sc) { u_int i, secbit, wscale; uint32_t iss, hash; uint8_t *secbits; union syncookie cookie; SCH_LOCK_ASSERT(sch); cookie.cookie = 0; /* Map our computed MSS into the 3-bit index. */ for (i = nitems(tcp_sc_msstab) - 1; tcp_sc_msstab[i] > sc->sc_peer_mss && i > 0; i--) ; cookie.flags.mss_idx = i; /* * Map the send window scale into the 3-bit index but only if * the wscale option was received. */ if (sc->sc_flags & SCF_WINSCALE) { wscale = sc->sc_requested_s_scale; for (i = nitems(tcp_sc_wstab) - 1; tcp_sc_wstab[i] > wscale && i > 0; i--) ; cookie.flags.wscale_idx = i; } /* Can we do SACK? */ if (sc->sc_flags & SCF_SACK) cookie.flags.sack_ok = 1; /* Which of the two secrets to use. */ secbit = sch->sch_sc->secret.oddeven & 0x1; cookie.flags.odd_even = secbit; secbits = sch->sch_sc->secret.key[secbit]; hash = syncookie_mac(&sc->sc_inc, sc->sc_irs, cookie.cookie, secbits, (uintptr_t)sch); /* * Put the flags into the hash and XOR them to get better ISS number * variance. This doesn't enhance the cryptographic strength and is * done to prevent the 8 cookie bits from showing up directly on the * wire. */ iss = hash & ~0xff; iss |= cookie.cookie ^ (hash >> 24); TCPSTAT_INC(tcps_sc_sendcookie); return (iss); } static struct syncache * syncookie_lookup(struct in_conninfo *inc, struct syncache_head *sch, struct syncache *sc, struct tcphdr *th, struct tcpopt *to, struct socket *lso) { uint32_t hash; uint8_t *secbits; tcp_seq ack, seq; int wnd, wscale = 0; union syncookie cookie; SCH_LOCK_ASSERT(sch); /* * Pull information out of SYN-ACK/ACK and revert sequence number * advances. */ ack = th->th_ack - 1; seq = th->th_seq - 1; /* * Unpack the flags containing enough information to restore the * connection. */ cookie.cookie = (ack & 0xff) ^ (ack >> 24); /* Which of the two secrets to use. */ secbits = sch->sch_sc->secret.key[cookie.flags.odd_even]; hash = syncookie_mac(inc, seq, cookie.cookie, secbits, (uintptr_t)sch); /* The recomputed hash matches the ACK if this was a genuine cookie. */ if ((ack & ~0xff) != (hash & ~0xff)) return (NULL); /* Fill in the syncache values. */ sc->sc_flags = 0; bcopy(inc, &sc->sc_inc, sizeof(struct in_conninfo)); sc->sc_ipopts = NULL; sc->sc_irs = seq; sc->sc_iss = ack; switch (inc->inc_flags & INC_ISIPV6) { #ifdef INET case 0: sc->sc_ip_ttl = sotoinpcb(lso)->inp_ip_ttl; sc->sc_ip_tos = sotoinpcb(lso)->inp_ip_tos; break; #endif #ifdef INET6 case INC_ISIPV6: if (sotoinpcb(lso)->inp_flags & IN6P_AUTOFLOWLABEL) sc->sc_flowlabel = sc->sc_iss & IPV6_FLOWLABEL_MASK; break; #endif } sc->sc_peer_mss = tcp_sc_msstab[cookie.flags.mss_idx]; /* We can simply recompute receive window scale we sent earlier. */ while (wscale < TCP_MAX_WINSHIFT && (TCP_MAXWIN << wscale) < sb_max) wscale++; /* Only use wscale if it was enabled in the orignal SYN. */ if (cookie.flags.wscale_idx > 0) { sc->sc_requested_r_scale = wscale; sc->sc_requested_s_scale = tcp_sc_wstab[cookie.flags.wscale_idx]; sc->sc_flags |= SCF_WINSCALE; } wnd = lso->sol_sbrcv_hiwat; wnd = imax(wnd, 0); wnd = imin(wnd, TCP_MAXWIN); sc->sc_wnd = wnd; if (cookie.flags.sack_ok) sc->sc_flags |= SCF_SACK; if (to->to_flags & TOF_TS) { sc->sc_flags |= SCF_TIMESTAMP; sc->sc_tsreflect = to->to_tsval; sc->sc_tsoff = tcp_new_ts_offset(inc); } if (to->to_flags & TOF_SIGNATURE) sc->sc_flags |= SCF_SIGNATURE; sc->sc_rxmits = 0; TCPSTAT_INC(tcps_sc_recvcookie); return (sc); } #ifdef INVARIANTS static int syncookie_cmp(struct in_conninfo *inc, struct syncache_head *sch, struct syncache *sc, struct tcphdr *th, struct tcpopt *to, struct socket *lso) { struct syncache scs, *scx; char *s; bzero(&scs, sizeof(scs)); scx = syncookie_lookup(inc, sch, &scs, th, to, lso); if ((s = tcp_log_addrs(inc, th, NULL, NULL)) == NULL) return (0); if (scx != NULL) { if (sc->sc_peer_mss != scx->sc_peer_mss) log(LOG_DEBUG, "%s; %s: mss different %i vs %i\n", s, __func__, sc->sc_peer_mss, scx->sc_peer_mss); if (sc->sc_requested_r_scale != scx->sc_requested_r_scale) log(LOG_DEBUG, "%s; %s: rwscale different %i vs %i\n", s, __func__, sc->sc_requested_r_scale, scx->sc_requested_r_scale); if (sc->sc_requested_s_scale != scx->sc_requested_s_scale) log(LOG_DEBUG, "%s; %s: swscale different %i vs %i\n", s, __func__, sc->sc_requested_s_scale, scx->sc_requested_s_scale); if ((sc->sc_flags & SCF_SACK) != (scx->sc_flags & SCF_SACK)) log(LOG_DEBUG, "%s; %s: SACK different\n", s, __func__); } if (s != NULL) free(s, M_TCPLOG); return (0); } #endif /* INVARIANTS */ static void syncookie_reseed(void *arg) { struct tcp_syncache *sc = arg; uint8_t *secbits; int secbit; /* * Reseeding the secret doesn't have to be protected by a lock. * It only must be ensured that the new random values are visible * to all CPUs in a SMP environment. The atomic with release * semantics ensures that. */ secbit = (sc->secret.oddeven & 0x1) ? 0 : 1; secbits = sc->secret.key[secbit]; arc4rand(secbits, SYNCOOKIE_SECRET_SIZE, 0); atomic_add_rel_int(&sc->secret.oddeven, 1); /* Reschedule ourself. */ callout_schedule(&sc->secret.reseed, SYNCOOKIE_LIFETIME * hz); } /* * Exports the syncache entries to userland so that netstat can display * them alongside the other sockets. This function is intended to be * called only from tcp_pcblist. * * Due to concurrency on an active system, the number of pcbs exported * may have no relation to max_pcbs. max_pcbs merely indicates the * amount of space the caller allocated for this function to use. */ int syncache_pcblist(struct sysctl_req *req, int max_pcbs, int *pcbs_exported) { struct xtcpcb xt; struct syncache *sc; struct syncache_head *sch; int count, error, i; for (count = 0, error = 0, i = 0; i < V_tcp_syncache.hashsize; i++) { sch = &V_tcp_syncache.hashbase[i]; SCH_LOCK(sch); TAILQ_FOREACH(sc, &sch->sch_bucket, sc_hash) { if (count >= max_pcbs) { SCH_UNLOCK(sch); goto exit; } if (cr_cansee(req->td->td_ucred, sc->sc_cred) != 0) continue; bzero(&xt, sizeof(xt)); xt.xt_len = sizeof(xt); if (sc->sc_inc.inc_flags & INC_ISIPV6) xt.xt_inp.inp_vflag = INP_IPV6; else xt.xt_inp.inp_vflag = INP_IPV4; bcopy(&sc->sc_inc, &xt.xt_inp.inp_inc, sizeof (struct in_conninfo)); xt.t_state = TCPS_SYN_RECEIVED; xt.xt_inp.xi_socket.xso_protocol = IPPROTO_TCP; xt.xt_inp.xi_socket.xso_len = sizeof (struct xsocket); xt.xt_inp.xi_socket.so_type = SOCK_STREAM; xt.xt_inp.xi_socket.so_state = SS_ISCONNECTING; error = SYSCTL_OUT(req, &xt, sizeof xt); if (error) { SCH_UNLOCK(sch); goto exit; } count++; } SCH_UNLOCK(sch); } exit: *pcbs_exported = count; return error; } Index: head/sys/netinet/tcp_timer.c =================================================================== --- head/sys/netinet/tcp_timer.c (revision 344366) +++ head/sys/netinet/tcp_timer.c (revision 344367) @@ -1,1064 +1,1061 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95 */ #include __FBSDID("$FreeBSD$"); #include "opt_inet.h" #include "opt_inet6.h" #include "opt_tcpdebug.h" #include "opt_rss.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET6 #include #endif #include #include #include #include #include #include #include #include #ifdef INET6 #include #endif #include #ifdef TCPDEBUG #include #endif int tcp_persmin; SYSCTL_PROC(_net_inet_tcp, OID_AUTO, persmin, CTLTYPE_INT|CTLFLAG_RW, &tcp_persmin, 0, sysctl_msec_to_ticks, "I", "minimum persistence interval"); int tcp_persmax; SYSCTL_PROC(_net_inet_tcp, OID_AUTO, persmax, CTLTYPE_INT|CTLFLAG_RW, &tcp_persmax, 0, sysctl_msec_to_ticks, "I", "maximum persistence interval"); int tcp_keepinit; SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW, &tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "time to establish connection"); int tcp_keepidle; SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle, CTLTYPE_INT|CTLFLAG_RW, &tcp_keepidle, 0, sysctl_msec_to_ticks, "I", "time before keepalive probes begin"); int tcp_keepintvl; SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW, &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "time between keepalive probes"); int tcp_delacktime; SYSCTL_PROC(_net_inet_tcp, TCPCTL_DELACKTIME, delacktime, CTLTYPE_INT|CTLFLAG_RW, &tcp_delacktime, 0, sysctl_msec_to_ticks, "I", "Time before a delayed ACK is sent"); int tcp_msl; SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW, &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime"); int tcp_rexmit_min; SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_min, CTLTYPE_INT|CTLFLAG_RW, &tcp_rexmit_min, 0, sysctl_msec_to_ticks, "I", "Minimum Retransmission Timeout"); int tcp_rexmit_slop; SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_slop, CTLTYPE_INT|CTLFLAG_RW, &tcp_rexmit_slop, 0, sysctl_msec_to_ticks, "I", "Retransmission Timer Slop"); int tcp_always_keepalive = 1; SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW, &tcp_always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections"); int tcp_fast_finwait2_recycle = 0; SYSCTL_INT(_net_inet_tcp, OID_AUTO, fast_finwait2_recycle, CTLFLAG_RW, &tcp_fast_finwait2_recycle, 0, "Recycle closed FIN_WAIT_2 connections faster"); int tcp_finwait2_timeout; SYSCTL_PROC(_net_inet_tcp, OID_AUTO, finwait2_timeout, CTLTYPE_INT|CTLFLAG_RW, &tcp_finwait2_timeout, 0, sysctl_msec_to_ticks, "I", "FIN-WAIT2 timeout"); int tcp_keepcnt = TCPTV_KEEPCNT; SYSCTL_INT(_net_inet_tcp, OID_AUTO, keepcnt, CTLFLAG_RW, &tcp_keepcnt, 0, "Number of keepalive probes to send"); /* max idle probes */ int tcp_maxpersistidle; int tcp_rexmit_drop_options = 0; SYSCTL_INT(_net_inet_tcp, OID_AUTO, rexmit_drop_options, CTLFLAG_RW, &tcp_rexmit_drop_options, 0, "Drop TCP options from 3rd and later retransmitted SYN"); VNET_DEFINE(int, tcp_pmtud_blackhole_detect); SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_detection, CTLFLAG_RW|CTLFLAG_VNET, &VNET_NAME(tcp_pmtud_blackhole_detect), 0, "Path MTU Discovery Black Hole Detection Enabled"); #ifdef INET VNET_DEFINE(int, tcp_pmtud_blackhole_mss) = 1200; SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_mss, CTLFLAG_RW|CTLFLAG_VNET, &VNET_NAME(tcp_pmtud_blackhole_mss), 0, "Path MTU Discovery Black Hole Detection lowered MSS"); #endif #ifdef INET6 VNET_DEFINE(int, tcp_v6pmtud_blackhole_mss) = 1220; SYSCTL_INT(_net_inet_tcp, OID_AUTO, v6pmtud_blackhole_mss, CTLFLAG_RW|CTLFLAG_VNET, &VNET_NAME(tcp_v6pmtud_blackhole_mss), 0, "Path MTU Discovery IPv6 Black Hole Detection lowered MSS"); #endif #ifdef RSS static int per_cpu_timers = 1; #else static int per_cpu_timers = 0; #endif SYSCTL_INT(_net_inet_tcp, OID_AUTO, per_cpu_timers, CTLFLAG_RW, &per_cpu_timers , 0, "run tcp timers on all cpus"); /* * Map the given inp to a CPU id. * * This queries RSS if it's compiled in, else it defaults to the current * CPU ID. */ inline int inp_to_cpuid(struct inpcb *inp) { u_int cpuid; #ifdef RSS if (per_cpu_timers) { cpuid = rss_hash2cpuid(inp->inp_flowid, inp->inp_flowtype); if (cpuid == NETISR_CPUID_NONE) return (curcpu); /* XXX */ else return (cpuid); } #else /* Legacy, pre-RSS behaviour */ if (per_cpu_timers) { /* * We don't have a flowid -> cpuid mapping, so cheat and * just map unknown cpuids to curcpu. Not the best, but * apparently better than defaulting to swi 0. */ cpuid = inp->inp_flowid % (mp_maxid + 1); if (! CPU_ABSENT(cpuid)) return (cpuid); return (curcpu); } #endif /* Default for RSS and non-RSS - cpuid 0 */ else { return (0); } } /* * Tcp protocol timeout routine called every 500 ms. * Updates timestamps used for TCP * causes finite state machine actions if timers expire. */ void tcp_slowtimo(void) { VNET_ITERATOR_DECL(vnet_iter); VNET_LIST_RLOCK_NOSLEEP(); VNET_FOREACH(vnet_iter) { CURVNET_SET(vnet_iter); (void) tcp_tw_2msl_scan(0); CURVNET_RESTORE(); } VNET_LIST_RUNLOCK_NOSLEEP(); } -int tcp_syn_backoff[TCP_MAXRXTSHIFT + 1] = - { 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 64, 64 }; - int tcp_backoff[TCP_MAXRXTSHIFT + 1] = { 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 512, 512, 512 }; int tcp_totbackoff = 2559; /* sum of tcp_backoff[] */ /* * TCP timer processing. */ void tcp_timer_delack(void *xtp) { struct tcpcb *tp = xtp; struct inpcb *inp; CURVNET_SET(tp->t_vnet); inp = tp->t_inpcb; KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); INP_WLOCK(inp); if (callout_pending(&tp->t_timers->tt_delack) || !callout_active(&tp->t_timers->tt_delack)) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } callout_deactivate(&tp->t_timers->tt_delack); if ((inp->inp_flags & INP_DROPPED) != 0) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } tp->t_flags |= TF_ACKNOW; TCPSTAT_INC(tcps_delack); (void) tp->t_fb->tfb_tcp_output(tp); INP_WUNLOCK(inp); CURVNET_RESTORE(); } void tcp_inpinfo_lock_del(struct inpcb *inp, struct tcpcb *tp) { if (inp && tp != NULL) INP_WUNLOCK(inp); } void tcp_timer_2msl(void *xtp) { struct tcpcb *tp = xtp; struct inpcb *inp; struct epoch_tracker et; CURVNET_SET(tp->t_vnet); #ifdef TCPDEBUG int ostate; ostate = tp->t_state; #endif inp = tp->t_inpcb; KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); INP_WLOCK(inp); tcp_free_sackholes(tp); if (callout_pending(&tp->t_timers->tt_2msl) || !callout_active(&tp->t_timers->tt_2msl)) { INP_WUNLOCK(tp->t_inpcb); CURVNET_RESTORE(); return; } callout_deactivate(&tp->t_timers->tt_2msl); if ((inp->inp_flags & INP_DROPPED) != 0) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0, ("%s: tp %p tcpcb can't be stopped here", __func__, tp)); /* * 2 MSL timeout in shutdown went off. If we're closed but * still waiting for peer to close and connection has been idle * too long delete connection control block. Otherwise, check * again in a bit. * * If in TIME_WAIT state just ignore as this timeout is handled in * tcp_tw_2msl_scan(). * * If fastrecycle of FIN_WAIT_2, in FIN_WAIT_2 and receiver has closed, * there's no point in hanging onto FIN_WAIT_2 socket. Just close it. * Ignore fact that there were recent incoming segments. */ if ((inp->inp_flags & INP_TIMEWAIT) != 0) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } if (tcp_fast_finwait2_recycle && tp->t_state == TCPS_FIN_WAIT_2 && tp->t_inpcb && tp->t_inpcb->inp_socket && (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) { TCPSTAT_INC(tcps_finwait2_drops); if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) { tcp_inpinfo_lock_del(inp, tp); goto out; } INP_INFO_RLOCK_ET(&V_tcbinfo, et); tp = tcp_close(tp); INP_INFO_RUNLOCK_ET(&V_tcbinfo, et); tcp_inpinfo_lock_del(inp, tp); goto out; } else { if (ticks - tp->t_rcvtime <= TP_MAXIDLE(tp)) { callout_reset(&tp->t_timers->tt_2msl, TP_KEEPINTVL(tp), tcp_timer_2msl, tp); } else { if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) { tcp_inpinfo_lock_del(inp, tp); goto out; } INP_INFO_RLOCK_ET(&V_tcbinfo, et); tp = tcp_close(tp); INP_INFO_RUNLOCK_ET(&V_tcbinfo, et); tcp_inpinfo_lock_del(inp, tp); goto out; } } #ifdef TCPDEBUG if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, PRU_SLOWTIMO); #endif TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO); if (tp != NULL) INP_WUNLOCK(inp); out: CURVNET_RESTORE(); } void tcp_timer_keep(void *xtp) { struct tcpcb *tp = xtp; struct tcptemp *t_template; struct inpcb *inp; struct epoch_tracker et; CURVNET_SET(tp->t_vnet); #ifdef TCPDEBUG int ostate; ostate = tp->t_state; #endif inp = tp->t_inpcb; KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); INP_WLOCK(inp); if (callout_pending(&tp->t_timers->tt_keep) || !callout_active(&tp->t_timers->tt_keep)) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } callout_deactivate(&tp->t_timers->tt_keep); if ((inp->inp_flags & INP_DROPPED) != 0) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0, ("%s: tp %p tcpcb can't be stopped here", __func__, tp)); /* * Because we don't regularly reset the keepalive callout in * the ESTABLISHED state, it may be that we don't actually need * to send a keepalive yet. If that occurs, schedule another * call for the next time the keepalive timer might expire. */ if (TCPS_HAVEESTABLISHED(tp->t_state)) { u_int idletime; idletime = ticks - tp->t_rcvtime; if (idletime < TP_KEEPIDLE(tp)) { callout_reset(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp) - idletime, tcp_timer_keep, tp); INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } } /* * Keep-alive timer went off; send something * or drop connection if idle for too long. */ TCPSTAT_INC(tcps_keeptimeo); if (tp->t_state < TCPS_ESTABLISHED) goto dropit; if ((tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) && tp->t_state <= TCPS_CLOSING) { if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp)) goto dropit; /* * Send a packet designed to force a response * if the peer is up and reachable: * either an ACK if the connection is still alive, * or an RST if the peer has closed the connection * due to timeout or reboot. * Using sequence number tp->snd_una-1 * causes the transmitted zero-length segment * to lie outside the receive window; * by the protocol spec, this requires the * correspondent TCP to respond. */ TCPSTAT_INC(tcps_keepprobe); t_template = tcpip_maketemplate(inp); if (t_template) { tcp_respond(tp, t_template->tt_ipgen, &t_template->tt_t, (struct mbuf *)NULL, tp->rcv_nxt, tp->snd_una - 1, 0); free(t_template, M_TEMP); } callout_reset(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp), tcp_timer_keep, tp); } else callout_reset(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp), tcp_timer_keep, tp); #ifdef TCPDEBUG if (inp->inp_socket->so_options & SO_DEBUG) tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, PRU_SLOWTIMO); #endif TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO); INP_WUNLOCK(inp); CURVNET_RESTORE(); return; dropit: TCPSTAT_INC(tcps_keepdrops); if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) { tcp_inpinfo_lock_del(inp, tp); goto out; } INP_INFO_RLOCK_ET(&V_tcbinfo, et); tp = tcp_drop(tp, ETIMEDOUT); #ifdef TCPDEBUG if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, PRU_SLOWTIMO); #endif TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO); INP_INFO_RUNLOCK_ET(&V_tcbinfo, et); tcp_inpinfo_lock_del(inp, tp); out: CURVNET_RESTORE(); } void tcp_timer_persist(void *xtp) { struct tcpcb *tp = xtp; struct inpcb *inp; struct epoch_tracker et; CURVNET_SET(tp->t_vnet); #ifdef TCPDEBUG int ostate; ostate = tp->t_state; #endif inp = tp->t_inpcb; KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); INP_WLOCK(inp); if (callout_pending(&tp->t_timers->tt_persist) || !callout_active(&tp->t_timers->tt_persist)) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } callout_deactivate(&tp->t_timers->tt_persist); if ((inp->inp_flags & INP_DROPPED) != 0) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0, ("%s: tp %p tcpcb can't be stopped here", __func__, tp)); /* * Persistence timer into zero window. * Force a byte to be output, if possible. */ TCPSTAT_INC(tcps_persisttimeo); /* * Hack: if the peer is dead/unreachable, we do not * time out if the window is closed. After a full * backoff, drop the connection if the idle time * (no responses to probes) reaches the maximum * backoff that we would use if retransmitting. */ if (tp->t_rxtshift == TCP_MAXRXTSHIFT && (ticks - tp->t_rcvtime >= tcp_maxpersistidle || ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) { TCPSTAT_INC(tcps_persistdrop); if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) { tcp_inpinfo_lock_del(inp, tp); goto out; } INP_INFO_RLOCK_ET(&V_tcbinfo, et); tp = tcp_drop(tp, ETIMEDOUT); INP_INFO_RUNLOCK_ET(&V_tcbinfo, et); tcp_inpinfo_lock_del(inp, tp); goto out; } /* * If the user has closed the socket then drop a persisting * connection after a much reduced timeout. */ if (tp->t_state > TCPS_CLOSE_WAIT && (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) { TCPSTAT_INC(tcps_persistdrop); if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) { tcp_inpinfo_lock_del(inp, tp); goto out; } INP_INFO_RLOCK_ET(&V_tcbinfo, et); tp = tcp_drop(tp, ETIMEDOUT); INP_INFO_RUNLOCK_ET(&V_tcbinfo, et); tcp_inpinfo_lock_del(inp, tp); goto out; } tcp_setpersist(tp); tp->t_flags |= TF_FORCEDATA; (void) tp->t_fb->tfb_tcp_output(tp); tp->t_flags &= ~TF_FORCEDATA; #ifdef TCPDEBUG if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG) tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO); #endif TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO); INP_WUNLOCK(inp); out: CURVNET_RESTORE(); } void tcp_timer_rexmt(void * xtp) { struct tcpcb *tp = xtp; CURVNET_SET(tp->t_vnet); int rexmt; struct inpcb *inp; struct epoch_tracker et; #ifdef TCPDEBUG int ostate; ostate = tp->t_state; #endif inp = tp->t_inpcb; KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); INP_WLOCK(inp); if (callout_pending(&tp->t_timers->tt_rexmt) || !callout_active(&tp->t_timers->tt_rexmt)) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } callout_deactivate(&tp->t_timers->tt_rexmt); if ((inp->inp_flags & INP_DROPPED) != 0) { INP_WUNLOCK(inp); CURVNET_RESTORE(); return; } KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0, ("%s: tp %p tcpcb can't be stopped here", __func__, tp)); tcp_free_sackholes(tp); TCP_LOG_EVENT(tp, NULL, NULL, NULL, TCP_LOG_RTO, 0, 0, NULL, false); if (tp->t_fb->tfb_tcp_rexmit_tmr) { /* The stack has a timer action too. */ (*tp->t_fb->tfb_tcp_rexmit_tmr)(tp); } /* * Retransmission timer went off. Message has not * been acked within retransmit interval. Back off * to a longer retransmit interval and retransmit one segment. */ if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { tp->t_rxtshift = TCP_MAXRXTSHIFT; TCPSTAT_INC(tcps_timeoutdrop); if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) { tcp_inpinfo_lock_del(inp, tp); goto out; } INP_INFO_RLOCK_ET(&V_tcbinfo, et); tp = tcp_drop(tp, ETIMEDOUT); INP_INFO_RUNLOCK_ET(&V_tcbinfo, et); tcp_inpinfo_lock_del(inp, tp); goto out; } if (tp->t_state == TCPS_SYN_SENT) { /* * If the SYN was retransmitted, indicate CWND to be * limited to 1 segment in cc_conn_init(). */ tp->snd_cwnd = 1; } else if (tp->t_rxtshift == 1) { /* * first retransmit; record ssthresh and cwnd so they can * be recovered if this turns out to be a "bad" retransmit. * A retransmit is considered "bad" if an ACK for this * segment is received within RTT/2 interval; the assumption * here is that the ACK was already in flight. See * "On Estimating End-to-End Network Path Properties" by * Allman and Paxson for more details. */ tp->snd_cwnd_prev = tp->snd_cwnd; tp->snd_ssthresh_prev = tp->snd_ssthresh; tp->snd_recover_prev = tp->snd_recover; if (IN_FASTRECOVERY(tp->t_flags)) tp->t_flags |= TF_WASFRECOVERY; else tp->t_flags &= ~TF_WASFRECOVERY; if (IN_CONGRECOVERY(tp->t_flags)) tp->t_flags |= TF_WASCRECOVERY; else tp->t_flags &= ~TF_WASCRECOVERY; if ((tp->t_flags & TF_RCVD_TSTMP) == 0) tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1)); /* In the event that we've negotiated timestamps * badrxtwin will be set to the value that we set * the retransmitted packet's to_tsval to by tcp_output */ tp->t_flags |= TF_PREVVALID; } else tp->t_flags &= ~TF_PREVVALID; TCPSTAT_INC(tcps_rexmttimeo); if ((tp->t_state == TCPS_SYN_SENT) || (tp->t_state == TCPS_SYN_RECEIVED)) - rexmt = TCPTV_RTOBASE * tcp_syn_backoff[tp->t_rxtshift]; + rexmt = TCPTV_RTOBASE * tcp_backoff[tp->t_rxtshift]; else rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift]; TCPT_RANGESET(tp->t_rxtcur, rexmt, tp->t_rttmin, TCPTV_REXMTMAX); /* * We enter the path for PLMTUD if connection is established or, if * connection is FIN_WAIT_1 status, reason for the last is that if * amount of data we send is very small, we could send it in couple of * packets and process straight to FIN. In that case we won't catch * ESTABLISHED state. */ if (V_tcp_pmtud_blackhole_detect && (((tp->t_state == TCPS_ESTABLISHED)) || (tp->t_state == TCPS_FIN_WAIT_1))) { #ifdef INET6 int isipv6; #endif /* * Idea here is that at each stage of mtu probe (usually, 1448 * -> 1188 -> 524) should be given 2 chances to recover before * further clamping down. 'tp->t_rxtshift % 2 == 0' should * take care of that. */ if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD|TF2_PLPMTU_MAXSEGSNT)) == (TF2_PLPMTU_PMTUD|TF2_PLPMTU_MAXSEGSNT)) && (tp->t_rxtshift >= 2 && tp->t_rxtshift < 6 && tp->t_rxtshift % 2 == 0)) { /* * Enter Path MTU Black-hole Detection mechanism: * - Disable Path MTU Discovery (IP "DF" bit). * - Reduce MTU to lower value than what we * negotiated with peer. */ if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) == 0) { /* Record that we may have found a black hole. */ tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE; /* Keep track of previous MSS. */ tp->t_pmtud_saved_maxseg = tp->t_maxseg; } /* * Reduce the MSS to blackhole value or to the default * in an attempt to retransmit. */ #ifdef INET6 isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? 1 : 0; if (isipv6 && tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss) { /* Use the sysctl tuneable blackhole MSS. */ tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss; TCPSTAT_INC(tcps_pmtud_blackhole_activated); } else if (isipv6) { /* Use the default MSS. */ tp->t_maxseg = V_tcp_v6mssdflt; /* * Disable Path MTU Discovery when we switch to * minmss. */ tp->t_flags2 &= ~TF2_PLPMTU_PMTUD; TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss); } #endif #if defined(INET6) && defined(INET) else #endif #ifdef INET if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss) { /* Use the sysctl tuneable blackhole MSS. */ tp->t_maxseg = V_tcp_pmtud_blackhole_mss; TCPSTAT_INC(tcps_pmtud_blackhole_activated); } else { /* Use the default MSS. */ tp->t_maxseg = V_tcp_mssdflt; /* * Disable Path MTU Discovery when we switch to * minmss. */ tp->t_flags2 &= ~TF2_PLPMTU_PMTUD; TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss); } #endif /* * Reset the slow-start flight size * as it may depend on the new MSS. */ if (CC_ALGO(tp)->conn_init != NULL) CC_ALGO(tp)->conn_init(tp->ccv); } else { /* * If further retransmissions are still unsuccessful * with a lowered MTU, maybe this isn't a blackhole and * we restore the previous MSS and blackhole detection * flags. * The limit '6' is determined by giving each probe * stage (1448, 1188, 524) 2 chances to recover. */ if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) && (tp->t_rxtshift >= 6)) { tp->t_flags2 |= TF2_PLPMTU_PMTUD; tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE; tp->t_maxseg = tp->t_pmtud_saved_maxseg; TCPSTAT_INC(tcps_pmtud_blackhole_failed); /* * Reset the slow-start flight size as it * may depend on the new MSS. */ if (CC_ALGO(tp)->conn_init != NULL) CC_ALGO(tp)->conn_init(tp->ccv); } } } /* * Disable RFC1323 and SACK if we haven't got any response to * our third SYN to work-around some broken terminal servers * (most of which have hopefully been retired) that have bad VJ * header compression code which trashes TCP segments containing * unknown-to-them TCP options. */ if (tcp_rexmit_drop_options && (tp->t_state == TCPS_SYN_SENT) && (tp->t_rxtshift == 3)) tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP|TF_SACK_PERMIT); /* * If we backed off this far, notify the L3 protocol that we're having * connection problems. */ if (tp->t_rxtshift > TCP_RTT_INVALIDATE) { #ifdef INET6 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) in6_losing(tp->t_inpcb); else #endif in_losing(tp->t_inpcb); } tp->snd_nxt = tp->snd_una; tp->snd_recover = tp->snd_max; /* * Force a segment to be sent. */ tp->t_flags |= TF_ACKNOW; /* * If timing a segment in this window, stop the timer. */ tp->t_rtttime = 0; cc_cong_signal(tp, NULL, CC_RTO); (void) tp->t_fb->tfb_tcp_output(tp); #ifdef TCPDEBUG if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, PRU_SLOWTIMO); #endif TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO); INP_WUNLOCK(inp); out: CURVNET_RESTORE(); } void tcp_timer_activate(struct tcpcb *tp, uint32_t timer_type, u_int delta) { struct callout *t_callout; timeout_t *f_callout; struct inpcb *inp = tp->t_inpcb; int cpu = inp_to_cpuid(inp); #ifdef TCP_OFFLOAD if (tp->t_flags & TF_TOE) return; #endif if (tp->t_timers->tt_flags & TT_STOPPED) return; switch (timer_type) { case TT_DELACK: t_callout = &tp->t_timers->tt_delack; f_callout = tcp_timer_delack; break; case TT_REXMT: t_callout = &tp->t_timers->tt_rexmt; f_callout = tcp_timer_rexmt; break; case TT_PERSIST: t_callout = &tp->t_timers->tt_persist; f_callout = tcp_timer_persist; break; case TT_KEEP: t_callout = &tp->t_timers->tt_keep; f_callout = tcp_timer_keep; break; case TT_2MSL: t_callout = &tp->t_timers->tt_2msl; f_callout = tcp_timer_2msl; break; default: if (tp->t_fb->tfb_tcp_timer_activate) { tp->t_fb->tfb_tcp_timer_activate(tp, timer_type, delta); return; } panic("tp %p bad timer_type %#x", tp, timer_type); } if (delta == 0) { callout_stop(t_callout); } else { callout_reset_on(t_callout, delta, f_callout, tp, cpu); } } int tcp_timer_active(struct tcpcb *tp, uint32_t timer_type) { struct callout *t_callout; switch (timer_type) { case TT_DELACK: t_callout = &tp->t_timers->tt_delack; break; case TT_REXMT: t_callout = &tp->t_timers->tt_rexmt; break; case TT_PERSIST: t_callout = &tp->t_timers->tt_persist; break; case TT_KEEP: t_callout = &tp->t_timers->tt_keep; break; case TT_2MSL: t_callout = &tp->t_timers->tt_2msl; break; default: if (tp->t_fb->tfb_tcp_timer_active) { return(tp->t_fb->tfb_tcp_timer_active(tp, timer_type)); } panic("tp %p bad timer_type %#x", tp, timer_type); } return callout_active(t_callout); } /* * Stop the timer from running, and apply a flag * against the timer_flags that will force the * timer never to run. The flag is needed to assure * a race does not leave it running and cause * the timer to possibly restart itself (keep and persist * especially do this). */ int tcp_timer_suspend(struct tcpcb *tp, uint32_t timer_type) { struct callout *t_callout; uint32_t t_flags; switch (timer_type) { case TT_DELACK: t_flags = TT_DELACK_SUS; t_callout = &tp->t_timers->tt_delack; break; case TT_REXMT: t_flags = TT_REXMT_SUS; t_callout = &tp->t_timers->tt_rexmt; break; case TT_PERSIST: t_flags = TT_PERSIST_SUS; t_callout = &tp->t_timers->tt_persist; break; case TT_KEEP: t_flags = TT_KEEP_SUS; t_callout = &tp->t_timers->tt_keep; break; case TT_2MSL: t_flags = TT_2MSL_SUS; t_callout = &tp->t_timers->tt_2msl; break; default: panic("tp:%p bad timer_type 0x%x", tp, timer_type); } tp->t_timers->tt_flags |= t_flags; return (callout_stop(t_callout)); } void tcp_timers_unsuspend(struct tcpcb *tp, uint32_t timer_type) { switch (timer_type) { case TT_DELACK: if (tp->t_timers->tt_flags & TT_DELACK_SUS) { tp->t_timers->tt_flags &= ~TT_DELACK_SUS; if (tp->t_flags & TF_DELACK) { /* Delayed ack timer should be up activate a timer */ tp->t_flags &= ~TF_DELACK; tcp_timer_activate(tp, TT_DELACK, tcp_delacktime); } } break; case TT_REXMT: if (tp->t_timers->tt_flags & TT_REXMT_SUS) { tp->t_timers->tt_flags &= ~TT_REXMT_SUS; if (SEQ_GT(tp->snd_max, tp->snd_una) && (tcp_timer_active((tp), TT_PERSIST) == 0) && tp->snd_wnd) { /* We have outstanding data activate a timer */ tcp_timer_activate(tp, TT_REXMT, tp->t_rxtcur); } } break; case TT_PERSIST: if (tp->t_timers->tt_flags & TT_PERSIST_SUS) { tp->t_timers->tt_flags &= ~TT_PERSIST_SUS; if (tp->snd_wnd == 0) { /* Activate the persists timer */ tp->t_rxtshift = 0; tcp_setpersist(tp); } } break; case TT_KEEP: if (tp->t_timers->tt_flags & TT_KEEP_SUS) { tp->t_timers->tt_flags &= ~TT_KEEP_SUS; tcp_timer_activate(tp, TT_KEEP, TCPS_HAVEESTABLISHED(tp->t_state) ? TP_KEEPIDLE(tp) : TP_KEEPINIT(tp)); } break; case TT_2MSL: if (tp->t_timers->tt_flags &= TT_2MSL_SUS) { tp->t_timers->tt_flags &= ~TT_2MSL_SUS; if ((tp->t_state == TCPS_FIN_WAIT_2) && ((tp->t_inpcb->inp_socket == NULL) || (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE))) { /* Star the 2MSL timer */ tcp_timer_activate(tp, TT_2MSL, (tcp_fast_finwait2_recycle) ? tcp_finwait2_timeout : TP_MAXIDLE(tp)); } } break; default: panic("tp:%p bad timer_type 0x%x", tp, timer_type); } } void tcp_timer_stop(struct tcpcb *tp, uint32_t timer_type) { struct callout *t_callout; tp->t_timers->tt_flags |= TT_STOPPED; switch (timer_type) { case TT_DELACK: t_callout = &tp->t_timers->tt_delack; break; case TT_REXMT: t_callout = &tp->t_timers->tt_rexmt; break; case TT_PERSIST: t_callout = &tp->t_timers->tt_persist; break; case TT_KEEP: t_callout = &tp->t_timers->tt_keep; break; case TT_2MSL: t_callout = &tp->t_timers->tt_2msl; break; default: if (tp->t_fb->tfb_tcp_timer_stop) { /* * XXXrrs we need to look at this with the * stop case below (flags). */ tp->t_fb->tfb_tcp_timer_stop(tp, timer_type); return; } panic("tp %p bad timer_type %#x", tp, timer_type); } if (callout_async_drain(t_callout, tcp_timer_discard) == 0) { /* * Can't stop the callout, defer tcpcb actual deletion * to the last one. We do this using the async drain * function and incrementing the count in */ tp->t_timers->tt_draincnt++; } } Index: head/sys/netinet/tcp_timer.h =================================================================== --- head/sys/netinet/tcp_timer.h (revision 344366) +++ head/sys/netinet/tcp_timer.h (revision 344367) @@ -1,231 +1,230 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1982, 1986, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93 * $FreeBSD$ */ #ifndef _NETINET_TCP_TIMER_H_ #define _NETINET_TCP_TIMER_H_ /* * The TCPT_REXMT timer is used to force retransmissions. * The TCP has the TCPT_REXMT timer set whenever segments * have been sent for which ACKs are expected but not yet * received. If an ACK is received which advances tp->snd_una, * then the retransmit timer is cleared (if there are no more * outstanding segments) or reset to the base value (if there * are more ACKs expected). Whenever the retransmit timer goes off, * we retransmit one unacknowledged segment, and do a backoff * on the retransmit timer. * * The TCPT_PERSIST timer is used to keep window size information * flowing even if the window goes shut. If all previous transmissions * have been acknowledged (so that there are no retransmissions in progress), * and the window is too small to bother sending anything, then we start * the TCPT_PERSIST timer. When it expires, if the window is nonzero, * we go to transmit state. Otherwise, at intervals send a single byte * into the peer's window to force him to update our window information. * We do this at most as often as TCPT_PERSMIN time intervals, * but no more frequently than the current estimate of round-trip * packet time. The TCPT_PERSIST timer is cleared whenever we receive * a window update from the peer. * * The TCPT_KEEP timer is used to keep connections alive. If an * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time, * but not yet established, then we drop the connection. Once the connection * is established, if the connection is idle for TCPTV_KEEP_IDLE time * (and keepalives have been enabled on the socket), we begin to probe * the connection. We force the peer to send us a segment by sending: * * This segment is (deliberately) outside the window, and should elicit * an ack segment in response from the peer. If, despite the TCPT_KEEP * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE * amount of time probing, then we drop the connection. */ /* * Time constants. */ #define TCPTV_MSL ( 30*hz) /* max seg lifetime (hah!) */ #define TCPTV_SRTTBASE 0 /* base roundtrip time; if 0, no idea yet */ #define TCPTV_RTOBASE ( 3*hz) /* assumed RTO if no info */ #define TCPTV_PERSMIN ( 5*hz) /* minimum persist interval */ #define TCPTV_PERSMAX ( 60*hz) /* maximum persist interval */ #define TCPTV_KEEP_INIT ( 75*hz) /* initial connect keepalive */ #define TCPTV_KEEP_IDLE (120*60*hz) /* dflt time before probing */ #define TCPTV_KEEPINTVL ( 75*hz) /* default probe interval */ #define TCPTV_KEEPCNT 8 /* max probes before drop */ #define TCPTV_FINWAIT2_TIMEOUT (60*hz) /* FIN_WAIT_2 timeout if no receiver */ /* * Minimum retransmit timer is 3 ticks, for algorithmic stability. * TCPT_RANGESET() will add another TCPTV_CPU_VAR to deal with * the expected worst-case processing variances by the kernels * representing the end points. Such variances do not always show * up in the srtt because the timestamp is often calculated at * the interface rather then at the TCP layer. This value is * typically 50ms. However, it is also possible that delayed * acks (typically 100ms) could create issues so we set the slop * to 200ms to try to cover it. Note that, properly speaking, * delayed-acks should not create a major issue for interactive * environments which 'P'ush the last segment, at least as * long as implementations do the required 'at least one ack * for every two packets' for the non-interactive streaming case. * (maybe the RTO calculation should use 2*RTT instead of RTT * to handle the ack-every-other-packet case). * * The prior minimum of 1*hz (1 second) badly breaks throughput on any * networks faster then a modem that has minor (e.g. 1%) packet loss. */ #define TCPTV_MIN ( hz/33 ) /* minimum allowable value */ #define TCPTV_CPU_VAR ( hz/5 ) /* cpu variance allowed (200ms) */ #define TCPTV_REXMTMAX ( 64*hz) /* max allowable REXMT value */ #define TCPTV_TWTRUNC 8 /* RTO factor to truncate TW */ #define TCP_LINGERTIME 120 /* linger at most 2 minutes */ #define TCP_MAXRXTSHIFT 12 /* maximum retransmits */ #define TCPTV_DELACK ( hz/10 ) /* 100ms timeout */ /* * If we exceed this number of retransmits for a single segment, we'll consider * the current srtt measurement no longer valid and will recalculate from * scratch starting with the next ACK. */ #define TCP_RTT_INVALIDATE (TCP_MAXRXTSHIFT / 4) #ifdef TCPTIMERS static const char *tcptimers[] = { "REXMT", "PERSIST", "KEEP", "2MSL", "DELACK" }; #endif /* * Force a time value to be in a certain range. */ #define TCPT_RANGESET(tv, value, tvmin, tvmax) do { \ (tv) = (value) + tcp_rexmit_slop; \ if ((u_long)(tv) < (u_long)(tvmin)) \ (tv) = (tvmin); \ if ((u_long)(tv) > (u_long)(tvmax)) \ (tv) = (tvmax); \ } while(0) #ifdef _KERNEL struct xtcp_timer; struct tcp_timer { struct callout tt_rexmt; /* retransmit timer */ struct callout tt_persist; /* retransmit persistence */ struct callout tt_keep; /* keepalive */ struct callout tt_2msl; /* 2*msl TIME_WAIT timer */ struct callout tt_delack; /* delayed ACK timer */ uint32_t tt_flags; /* Timers flags */ uint32_t tt_draincnt; /* Count being drained */ }; /* * Flags for the tt_flags field. */ #define TT_DELACK 0x0001 #define TT_REXMT 0x0002 #define TT_PERSIST 0x0004 #define TT_KEEP 0x0008 #define TT_2MSL 0x0010 #define TT_MASK (TT_DELACK|TT_REXMT|TT_PERSIST|TT_KEEP|TT_2MSL) /* * Suspend flags - used when suspending a timer * from ever running again. */ #define TT_DELACK_SUS 0x0100 #define TT_REXMT_SUS 0x0200 #define TT_PERSIST_SUS 0x0400 #define TT_KEEP_SUS 0x0800 #define TT_2MSL_SUS 0x1000 #define TT_STOPPED 0x00010000 #define TP_KEEPINIT(tp) ((tp)->t_keepinit ? (tp)->t_keepinit : tcp_keepinit) #define TP_KEEPIDLE(tp) ((tp)->t_keepidle ? (tp)->t_keepidle : tcp_keepidle) #define TP_KEEPINTVL(tp) ((tp)->t_keepintvl ? (tp)->t_keepintvl : tcp_keepintvl) #define TP_KEEPCNT(tp) ((tp)->t_keepcnt ? (tp)->t_keepcnt : tcp_keepcnt) #define TP_MAXIDLE(tp) (TP_KEEPCNT(tp) * TP_KEEPINTVL(tp)) extern int tcp_persmin; /* minimum persist interval */ extern int tcp_persmax; /* maximum persist interval */ extern int tcp_keepinit; /* time to establish connection */ extern int tcp_keepidle; /* time before keepalive probes begin */ extern int tcp_keepintvl; /* time between keepalive probes */ extern int tcp_keepcnt; /* number of keepalives */ extern int tcp_delacktime; /* time before sending a delayed ACK */ extern int tcp_maxpersistidle; extern int tcp_rexmit_min; extern int tcp_rexmit_slop; extern int tcp_msl; extern int tcp_ttl; /* time to live for TCP segs */ extern int tcp_backoff[]; -extern int tcp_syn_backoff[]; extern int tcp_totbackoff; extern int tcp_rexmit_drop_options; extern int tcp_always_keepalive; extern int tcp_finwait2_timeout; extern int tcp_fast_finwait2_recycle; VNET_DECLARE(int, tcp_pmtud_blackhole_detect); #define V_tcp_pmtud_blackhole_detect VNET(tcp_pmtud_blackhole_detect) VNET_DECLARE(int, tcp_pmtud_blackhole_mss); #define V_tcp_pmtud_blackhole_mss VNET(tcp_pmtud_blackhole_mss) VNET_DECLARE(int, tcp_v6pmtud_blackhole_mss); #define V_tcp_v6pmtud_blackhole_mss VNET(tcp_v6pmtud_blackhole_mss) void tcp_inpinfo_lock_del(struct inpcb *inp, struct tcpcb *tp); void tcp_timer_init(void); void tcp_timer_2msl(void *xtp); void tcp_timer_discard(void *); struct tcptw * tcp_tw_2msl_scan(int reuse); /* XXX temporary? */ void tcp_timer_keep(void *xtp); void tcp_timer_persist(void *xtp); void tcp_timer_rexmt(void *xtp); void tcp_timer_delack(void *xtp); #endif /* _KERNEL */ #endif /* !_NETINET_TCP_TIMER_H_ */