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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 */

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