Index: sys/netinet/tcp_input.c =================================================================== --- sys/netinet/tcp_input.c +++ sys/netinet/tcp_input.c @@ -489,13 +489,11 @@ * 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) \ ((!tcp_timer_active(tp, TT_DELACK) && \ (tp->t_flags & TF_RXWIN0SENT) == 0) && \ - (tlen <= tp->t_maxopd) && \ + (tlen <= tp->t_maxseg) && \ (V_tcp_delack_enabled || (tp->t_flags & TF_NEEDSYN))) static void inline @@ -3399,11 +3397,9 @@ * While looking at the routing entry, we also initialize other path-dependent * parameters from pre-set or cached values in the routing entry. * - * Also take into account the space needed for options that we - * send regularly. Make maxseg shorter by that amount to assure - * that we can send maxseg amount of data even when the options - * are present. Store the upper limit of the length of options plus - * data in maxopd. + * NOTE that resulting t_maxseg doesn't include space for TCP options or + * IP options, e.g. IPSEC data, since length of this data may vary, and + * thus it is calculated for every segment separately in tcp_output(). * * NOTE that this routine is only called when we process an incoming * segment, or an ICMP need fragmentation datagram. Outgoing SYN/ACK MSS @@ -3417,7 +3413,6 @@ u_long maxmtu = 0; struct inpcb *inp = tp->t_inpcb; struct hc_metrics_lite metrics; - int origoffer; #ifdef INET6 int isipv6 = ((inp->inp_vflag & INP_IPV6) != 0) ? 1 : 0; size_t min_protoh = isipv6 ? @@ -3433,13 +3428,12 @@ KASSERT(offer == -1, ("%s: conflict", __func__)); offer = mtuoffer - min_protoh; } - origoffer = offer; /* Initialize. */ #ifdef INET6 if (isipv6) { maxmtu = tcp_maxmtu6(&inp->inp_inc, cap); - tp->t_maxopd = tp->t_maxseg = V_tcp_v6mssdflt; + tp->t_maxseg = V_tcp_v6mssdflt; } #endif #if defined(INET) && defined(INET6) @@ -3448,7 +3442,7 @@ #ifdef INET { maxmtu = tcp_maxmtu(&inp->inp_inc, cap); - tp->t_maxopd = tp->t_maxseg = V_tcp_mssdflt; + tp->t_maxseg = V_tcp_mssdflt; } #endif @@ -3472,9 +3466,9 @@ /* * Offer == 0 means that there was no MSS on the SYN * segment, in this case we use tcp_mssdflt as - * already assigned to t_maxopd above. + * already assigned to t_maxseg above. */ - offer = tp->t_maxopd; + offer = tp->t_maxseg; break; case -1: @@ -3545,32 +3539,6 @@ } mss = min(mss, offer); - /* - * Sanity check: make sure that maxopd will be large - * enough to allow some data on segments even if the - * all the option space is used (40bytes). Otherwise - * funny things may happen in tcp_output. - */ - mss = max(mss, 64); - - /* - * maxopd stores the maximum length of data AND options - * in a segment; maxseg is the amount of data in a normal - * segment. We need to store this value (maxopd) apart - * from maxseg, because now every segment carries options - * and thus we normally have somewhat less data in segments. - */ - tp->t_maxopd = mss; - - /* - * origoffer==-1 indicates that no segments were received yet. - * In this case we just guess. - */ - if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && - (origoffer == -1 || - (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP)) - mss -= TCPOLEN_TSTAMP_APPA; - tp->t_maxseg = mss; } Index: sys/netinet/tcp_output.c =================================================================== --- sys/netinet/tcp_output.c +++ sys/netinet/tcp_output.c @@ -777,11 +777,11 @@ /* * Adjust data length if insertion of options will - * bump the packet length beyond the t_maxopd length. + * 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_maxopd) { + if (len + optlen + ipoptlen > tp->t_maxseg) { flags &= ~TH_FIN; if (tso) { @@ -874,7 +874,7 @@ * fractional unless the send sockbuf can be * emptied: */ - max_len = (tp->t_maxopd - optlen); + max_len = (tp->t_maxseg - optlen); if ((off + len) < sbavail(&so->so_snd)) { moff = len % max_len; if (moff != 0) { @@ -904,7 +904,7 @@ sendalot = 1; } else { - len = tp->t_maxopd - optlen - ipoptlen; + len = tp->t_maxseg - optlen - ipoptlen; sendalot = 1; } } else @@ -1214,10 +1214,10 @@ * The TCP pseudo header checksum is always provided. */ if (tso) { - KASSERT(len > tp->t_maxopd - optlen, + 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_maxopd - optlen; + m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen; } #ifdef IPSEC @@ -1284,7 +1284,7 @@ */ ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6)); - if (V_path_mtu_discovery && tp->t_maxopd > V_tcp_minmss) + if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) tp->t_flags2 |= TF2_PLPMTU_PMTUD; else tp->t_flags2 &= ~TF2_PLPMTU_PMTUD; @@ -1325,7 +1325,7 @@ * * NB: Don't set DF on small MTU/MSS to have a safe fallback. */ - if (V_path_mtu_discovery && tp->t_maxopd > V_tcp_minmss) { + if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) { ip->ip_off |= htons(IP_DF); tp->t_flags2 |= TF2_PLPMTU_PMTUD; } else { Index: sys/netinet/tcp_subr.c =================================================================== --- sys/netinet/tcp_subr.c +++ sys/netinet/tcp_subr.c @@ -787,7 +787,7 @@ #endif tp->t_timers = &tm->tt; /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */ - tp->t_maxseg = tp->t_maxopd = + tp->t_maxseg = #ifdef INET6 isipv6 ? V_tcp_v6mssdflt : #endif /* INET6 */ Index: sys/netinet/tcp_timer.c =================================================================== --- sys/netinet/tcp_timer.c +++ sys/netinet/tcp_timer.c @@ -653,7 +653,6 @@ */ if (V_tcp_pmtud_blackhole_detect && (((tp->t_state == TCPS_ESTABLISHED)) || (tp->t_state == TCPS_FIN_WAIT_1))) { - int optlen; #ifdef INET6 int isipv6; #endif @@ -671,8 +670,7 @@ tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE; /* Keep track of previous MSS. */ - optlen = tp->t_maxopd - tp->t_maxseg; - tp->t_pmtud_saved_maxopd = tp->t_maxopd; + tp->t_pmtud_saved_maxseg = tp->t_maxseg; /* * Reduce the MSS to blackhole value or to the default @@ -681,13 +679,13 @@ #ifdef INET6 isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? 1 : 0; if (isipv6 && - tp->t_maxopd > V_tcp_v6pmtud_blackhole_mss) { + tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss) { /* Use the sysctl tuneable blackhole MSS. */ - tp->t_maxopd = V_tcp_v6pmtud_blackhole_mss; + tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss; V_tcp_pmtud_blackhole_activated++; } else if (isipv6) { /* Use the default MSS. */ - tp->t_maxopd = V_tcp_v6mssdflt; + tp->t_maxseg = V_tcp_v6mssdflt; /* * Disable Path MTU Discovery when we switch to * minmss. @@ -700,13 +698,13 @@ else #endif #ifdef INET - if (tp->t_maxopd > V_tcp_pmtud_blackhole_mss) { + if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss) { /* Use the sysctl tuneable blackhole MSS. */ - tp->t_maxopd = V_tcp_pmtud_blackhole_mss; + tp->t_maxseg = V_tcp_pmtud_blackhole_mss; V_tcp_pmtud_blackhole_activated++; } else { /* Use the default MSS. */ - tp->t_maxopd = V_tcp_mssdflt; + tp->t_maxseg = V_tcp_mssdflt; /* * Disable Path MTU Discovery when we switch to * minmss. @@ -715,7 +713,6 @@ V_tcp_pmtud_blackhole_activated_min_mss++; } #endif - tp->t_maxseg = tp->t_maxopd - optlen; /* * Reset the slow-start flight size * as it may depend on the new MSS. @@ -733,9 +730,7 @@ (tp->t_rxtshift > 4)) { tp->t_flags2 |= TF2_PLPMTU_PMTUD; tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE; - optlen = tp->t_maxopd - tp->t_maxseg; - tp->t_maxopd = tp->t_pmtud_saved_maxopd; - tp->t_maxseg = tp->t_maxopd - optlen; + tp->t_maxseg = tp->t_pmtud_saved_maxseg; V_tcp_pmtud_blackhole_failed++; /* * Reset the slow-start flight size as it Index: sys/netinet/tcp_usrreq.c =================================================================== --- sys/netinet/tcp_usrreq.c +++ sys/netinet/tcp_usrreq.c @@ -865,8 +865,7 @@ /* * Do implied connect if not yet connected, * initialize window to default value, and - * initialize maxseg/maxopd using peer's cached - * MSS. + * initialize maxseg using peer's cached MSS. */ #ifdef INET6 if (isipv6) @@ -925,8 +924,7 @@ /* * Do implied connect if not yet connected, * initialize window to default value, and - * initialize maxseg/maxopd using peer's cached - * MSS. + * initialize maxseg using peer's cached MSS. */ #ifdef INET6 if (isipv6) @@ -2027,8 +2025,8 @@ "0x%08x\n", tp->snd_ssthresh, tp->snd_recover); db_print_indent(indent); - db_printf("t_maxopd: %u t_rcvtime: %u t_startime: %u\n", - tp->t_maxopd, tp->t_rcvtime, tp->t_starttime); + db_printf("t_rcvtime: %u t_startime: %u\n", + tp->t_rcvtime, tp->t_starttime); db_print_indent(indent); db_printf("t_rttime: %u t_rtsq: 0x%08x\n", Index: sys/netinet/tcp_var.h =================================================================== --- sys/netinet/tcp_var.h +++ sys/netinet/tcp_var.h @@ -140,8 +140,6 @@ u_long snd_spare2; /* unused */ tcp_seq snd_recover; /* for use in NewReno Fast Recovery */ - u_int t_maxopd; /* mss plus options */ - u_int t_rcvtime; /* inactivity time */ u_int t_starttime; /* time connection was established */ u_int t_rtttime; /* RTT measurement start time */ @@ -152,6 +150,7 @@ int t_rxtcur; /* current retransmit value (ticks) */ u_int t_maxseg; /* maximum segment size */ + u_int t_pmtud_saved_maxseg; /* pre-blackhole MSS */ int t_srtt; /* smoothed round-trip time */ int t_rttvar; /* variance in round-trip time */ @@ -211,7 +210,6 @@ u_int t_tsomax; /* TSO total burst length limit in bytes */ u_int t_tsomaxsegcount; /* TSO maximum segment count */ u_int t_tsomaxsegsize; /* TSO maximum segment size in bytes */ - u_int t_pmtud_saved_maxopd; /* pre-blackhole MSS */ u_int t_flags2; /* More tcpcb flags storage */ uint32_t t_ispare[8]; /* 5 UTO, 3 TBD */