2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved.
3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved.
5 * This code is derived from software contributed to The DragonFly Project
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of The DragonFly Project nor the names of its
17 * contributors may be used to endorse or promote products derived
18 * from this software without specific, prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * All advertising materials mentioning features or use of this software
36 * must display the following acknowledgement:
37 * This product includes software developed by Jeffrey M. Hsu.
39 * Copyright (c) 2001 Networks Associates Technologies, Inc.
40 * All rights reserved.
42 * This software was developed for the FreeBSD Project by Jonathan Lemon
43 * and NAI Labs, the Security Research Division of Network Associates, Inc.
44 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
45 * DARPA CHATS research program.
47 * Redistribution and use in source and binary forms, with or without
48 * modification, are permitted provided that the following conditions
50 * 1. Redistributions of source code must retain the above copyright
51 * notice, this list of conditions and the following disclaimer.
52 * 2. Redistributions in binary form must reproduce the above copyright
53 * notice, this list of conditions and the following disclaimer in the
54 * documentation and/or other materials provided with the distribution.
55 * 3. The name of the author may not be used to endorse or promote
56 * products derived from this software without specific prior written
59 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
60 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
61 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
62 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
63 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
64 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
65 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
66 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
67 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
68 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
71 * $FreeBSD: src/sys/netinet/tcp_syncache.c,v 1.5.2.14 2003/02/24 04:02:27 silby Exp $
72 * $DragonFly: src/sys/netinet/tcp_syncache.c,v 1.35 2008/11/22 11:03:35 sephe Exp $
75 #include "opt_inet6.h"
76 #include "opt_ipsec.h"
78 #include <sys/param.h>
79 #include <sys/systm.h>
80 #include <sys/kernel.h>
81 #include <sys/sysctl.h>
82 #include <sys/malloc.h>
85 #include <sys/proc.h> /* for proc0 declaration */
86 #include <sys/random.h>
87 #include <sys/socket.h>
88 #include <sys/socketvar.h>
89 #include <sys/in_cksum.h>
91 #include <sys/msgport2.h>
92 #include <net/netmsg2.h>
95 #include <net/route.h>
97 #include <netinet/in.h>
98 #include <netinet/in_systm.h>
99 #include <netinet/ip.h>
100 #include <netinet/in_var.h>
101 #include <netinet/in_pcb.h>
102 #include <netinet/ip_var.h>
103 #include <netinet/ip6.h>
105 #include <netinet/icmp6.h>
106 #include <netinet6/nd6.h>
108 #include <netinet6/ip6_var.h>
109 #include <netinet6/in6_pcb.h>
110 #include <netinet/tcp.h>
111 #include <netinet/tcp_fsm.h>
112 #include <netinet/tcp_seq.h>
113 #include <netinet/tcp_timer.h>
114 #include <netinet/tcp_timer2.h>
115 #include <netinet/tcp_var.h>
116 #include <netinet6/tcp6_var.h>
119 #include <netinet6/ipsec.h>
121 #include <netinet6/ipsec6.h>
123 #include <netproto/key/key.h>
127 #include <netproto/ipsec/ipsec.h>
129 #include <netproto/ipsec/ipsec6.h>
131 #include <netproto/ipsec/key.h>
133 #endif /*FAST_IPSEC*/
135 static int tcp_syncookies = 1;
136 SYSCTL_INT(_net_inet_tcp, OID_AUTO, syncookies, CTLFLAG_RW,
138 "Use TCP SYN cookies if the syncache overflows");
140 static void syncache_drop(struct syncache *, struct syncache_head *);
141 static void syncache_free(struct syncache *);
142 static void syncache_insert(struct syncache *, struct syncache_head *);
143 struct syncache *syncache_lookup(struct in_conninfo *, struct syncache_head **);
144 static int syncache_respond(struct syncache *, struct mbuf *);
145 static struct socket *syncache_socket(struct syncache *, struct socket *,
147 static void syncache_timer(void *);
148 static u_int32_t syncookie_generate(struct syncache *);
149 static struct syncache *syncookie_lookup(struct in_conninfo *,
150 struct tcphdr *, struct socket *);
153 * Transmit the SYN,ACK fewer times than TCP_MAXRXTSHIFT specifies.
154 * 3 retransmits corresponds to a timeout of (1 + 2 + 4 + 8 == 15) seconds,
155 * the odds are that the user has given up attempting to connect by then.
157 #define SYNCACHE_MAXREXMTS 3
159 /* Arbitrary values */
160 #define TCP_SYNCACHE_HASHSIZE 512
161 #define TCP_SYNCACHE_BUCKETLIMIT 30
163 struct netmsg_sc_timer {
164 struct netmsg nm_netmsg;
165 struct msgrec *nm_mrec; /* back pointer to containing msgrec */
169 struct netmsg_sc_timer msg;
170 lwkt_port_t port; /* constant after init */
171 int slot; /* constant after init */
174 static void syncache_timer_handler(netmsg_t);
176 struct tcp_syncache {
184 static struct tcp_syncache tcp_syncache;
186 struct tcp_syncache_percpu {
187 struct syncache_head *hashbase;
189 TAILQ_HEAD(, syncache) timerq[SYNCACHE_MAXREXMTS + 1];
190 struct callout tt_timerq[SYNCACHE_MAXREXMTS + 1];
191 struct msgrec mrec[SYNCACHE_MAXREXMTS + 1];
193 static struct tcp_syncache_percpu tcp_syncache_percpu[MAXCPU];
195 static struct lwkt_port syncache_null_rport;
197 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, syncache, CTLFLAG_RW, 0, "TCP SYN cache");
199 SYSCTL_INT(_net_inet_tcp_syncache, OID_AUTO, bucketlimit, CTLFLAG_RD,
200 &tcp_syncache.bucket_limit, 0, "Per-bucket hash limit for syncache");
202 SYSCTL_INT(_net_inet_tcp_syncache, OID_AUTO, cachelimit, CTLFLAG_RD,
203 &tcp_syncache.cache_limit, 0, "Overall entry limit for syncache");
207 SYSCTL_INT(_net_inet_tcp_syncache, OID_AUTO, count, CTLFLAG_RD,
208 &tcp_syncache.cache_count, 0, "Current number of entries in syncache");
211 SYSCTL_INT(_net_inet_tcp_syncache, OID_AUTO, hashsize, CTLFLAG_RD,
212 &tcp_syncache.hashsize, 0, "Size of TCP syncache hashtable");
214 SYSCTL_INT(_net_inet_tcp_syncache, OID_AUTO, rexmtlimit, CTLFLAG_RW,
215 &tcp_syncache.rexmt_limit, 0, "Limit on SYN/ACK retransmissions");
217 static MALLOC_DEFINE(M_SYNCACHE, "syncache", "TCP syncache");
219 #define SYNCACHE_HASH(inc, mask) \
220 ((tcp_syncache.hash_secret ^ \
221 (inc)->inc_faddr.s_addr ^ \
222 ((inc)->inc_faddr.s_addr >> 16) ^ \
223 (inc)->inc_fport ^ (inc)->inc_lport) & mask)
225 #define SYNCACHE_HASH6(inc, mask) \
226 ((tcp_syncache.hash_secret ^ \
227 (inc)->inc6_faddr.s6_addr32[0] ^ \
228 (inc)->inc6_faddr.s6_addr32[3] ^ \
229 (inc)->inc_fport ^ (inc)->inc_lport) & mask)
231 #define ENDPTS_EQ(a, b) ( \
232 (a)->ie_fport == (b)->ie_fport && \
233 (a)->ie_lport == (b)->ie_lport && \
234 (a)->ie_faddr.s_addr == (b)->ie_faddr.s_addr && \
235 (a)->ie_laddr.s_addr == (b)->ie_laddr.s_addr \
238 #define ENDPTS6_EQ(a, b) (memcmp(a, b, sizeof(*a)) == 0)
241 syncache_timeout(struct tcp_syncache_percpu *syncache_percpu,
242 struct syncache *sc, int slot)
244 sc->sc_rxtslot = slot;
245 sc->sc_rxttime = ticks + TCPTV_RTOBASE * tcp_backoff[slot];
247 TAILQ_INSERT_TAIL(&syncache_percpu->timerq[slot], sc, sc_timerq);
248 if (!callout_active(&syncache_percpu->tt_timerq[slot])) {
249 callout_reset(&syncache_percpu->tt_timerq[slot],
250 TCPTV_RTOBASE * tcp_backoff[slot],
252 &syncache_percpu->mrec[slot]);
258 syncache_free(struct syncache *sc)
262 const boolean_t isipv6 = sc->sc_inc.inc_isipv6;
264 const boolean_t isipv6 = FALSE;
268 m_free(sc->sc_ipopts);
270 rt = isipv6 ? sc->sc_route6.ro_rt : sc->sc_route.ro_rt;
273 * If this is the only reference to a protocol-cloned
274 * route, remove it immediately.
276 if ((rt->rt_flags & RTF_WASCLONED) && rt->rt_refcnt == 1)
277 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
278 rt_mask(rt), rt->rt_flags, NULL);
281 kfree(sc, M_SYNCACHE);
289 tcp_syncache.hashsize = TCP_SYNCACHE_HASHSIZE;
290 tcp_syncache.bucket_limit = TCP_SYNCACHE_BUCKETLIMIT;
291 tcp_syncache.cache_limit =
292 tcp_syncache.hashsize * tcp_syncache.bucket_limit;
293 tcp_syncache.rexmt_limit = SYNCACHE_MAXREXMTS;
294 tcp_syncache.hash_secret = karc4random();
296 TUNABLE_INT_FETCH("net.inet.tcp.syncache.hashsize",
297 &tcp_syncache.hashsize);
298 TUNABLE_INT_FETCH("net.inet.tcp.syncache.cachelimit",
299 &tcp_syncache.cache_limit);
300 TUNABLE_INT_FETCH("net.inet.tcp.syncache.bucketlimit",
301 &tcp_syncache.bucket_limit);
302 if (!powerof2(tcp_syncache.hashsize)) {
303 kprintf("WARNING: syncache hash size is not a power of 2.\n");
304 tcp_syncache.hashsize = 512; /* safe default */
306 tcp_syncache.hashmask = tcp_syncache.hashsize - 1;
308 lwkt_initport_replyonly_null(&syncache_null_rport);
310 for (cpu = 0; cpu < ncpus2; cpu++) {
311 struct tcp_syncache_percpu *syncache_percpu;
313 syncache_percpu = &tcp_syncache_percpu[cpu];
314 /* Allocate the hash table. */
315 MALLOC(syncache_percpu->hashbase, struct syncache_head *,
316 tcp_syncache.hashsize * sizeof(struct syncache_head),
317 M_SYNCACHE, M_WAITOK);
319 /* Initialize the hash buckets. */
320 for (i = 0; i < tcp_syncache.hashsize; i++) {
321 struct syncache_head *bucket;
323 bucket = &syncache_percpu->hashbase[i];
324 TAILQ_INIT(&bucket->sch_bucket);
325 bucket->sch_length = 0;
328 for (i = 0; i <= SYNCACHE_MAXREXMTS; i++) {
329 /* Initialize the timer queues. */
330 TAILQ_INIT(&syncache_percpu->timerq[i]);
331 callout_init(&syncache_percpu->tt_timerq[i]);
333 syncache_percpu->mrec[i].slot = i;
334 syncache_percpu->mrec[i].port = tcp_cport(cpu);
335 syncache_percpu->mrec[i].msg.nm_mrec =
336 &syncache_percpu->mrec[i];
337 netmsg_init(&syncache_percpu->mrec[i].msg.nm_netmsg,
338 NULL, &syncache_null_rport,
339 0, syncache_timer_handler);
345 syncache_insert(struct syncache *sc, struct syncache_head *sch)
347 struct tcp_syncache_percpu *syncache_percpu;
348 struct syncache *sc2;
351 syncache_percpu = &tcp_syncache_percpu[mycpu->gd_cpuid];
354 * Make sure that we don't overflow the per-bucket
355 * limit or the total cache size limit.
357 if (sch->sch_length >= tcp_syncache.bucket_limit) {
359 * The bucket is full, toss the oldest element.
361 sc2 = TAILQ_FIRST(&sch->sch_bucket);
362 sc2->sc_tp->ts_recent = ticks;
363 syncache_drop(sc2, sch);
364 tcpstat.tcps_sc_bucketoverflow++;
365 } else if (syncache_percpu->cache_count >= tcp_syncache.cache_limit) {
367 * The cache is full. Toss the oldest entry in the
368 * entire cache. This is the front entry in the
369 * first non-empty timer queue with the largest
372 for (i = SYNCACHE_MAXREXMTS; i >= 0; i--) {
373 sc2 = TAILQ_FIRST(&syncache_percpu->timerq[i]);
377 sc2->sc_tp->ts_recent = ticks;
378 syncache_drop(sc2, NULL);
379 tcpstat.tcps_sc_cacheoverflow++;
382 /* Initialize the entry's timer. */
383 syncache_timeout(syncache_percpu, sc, 0);
385 /* Put it into the bucket. */
386 TAILQ_INSERT_TAIL(&sch->sch_bucket, sc, sc_hash);
388 syncache_percpu->cache_count++;
389 tcpstat.tcps_sc_added++;
393 syncache_destroy(struct tcpcb *tp)
395 struct tcp_syncache_percpu *syncache_percpu;
396 struct syncache_head *bucket;
400 syncache_percpu = &tcp_syncache_percpu[mycpu->gd_cpuid];
402 for (i = 0; i < tcp_syncache.hashsize; i++) {
403 bucket = &syncache_percpu->hashbase[i];
404 TAILQ_FOREACH(sc, &bucket->sch_bucket, sc_hash) {
405 if (sc->sc_tp == tp) {
407 tp->t_flags &= ~TF_SYNCACHE;
412 kprintf("Warning: delete stale syncache for tp=%p, sc=%p\n", tp, sc);
416 syncache_drop(struct syncache *sc, struct syncache_head *sch)
418 struct tcp_syncache_percpu *syncache_percpu;
420 const boolean_t isipv6 = sc->sc_inc.inc_isipv6;
422 const boolean_t isipv6 = FALSE;
425 syncache_percpu = &tcp_syncache_percpu[mycpu->gd_cpuid];
429 sch = &syncache_percpu->hashbase[
430 SYNCACHE_HASH6(&sc->sc_inc, tcp_syncache.hashmask)];
432 sch = &syncache_percpu->hashbase[
433 SYNCACHE_HASH(&sc->sc_inc, tcp_syncache.hashmask)];
437 TAILQ_REMOVE(&sch->sch_bucket, sc, sc_hash);
439 syncache_percpu->cache_count--;
445 sc->sc_tp->t_flags &= ~TF_SYNCACHE;
450 * Remove the entry from the syncache timer/timeout queue. Note
451 * that we do not try to stop any running timer since we do not know
452 * whether the timer's message is in-transit or not. Since timeouts
453 * are fairly long, taking an unneeded callout does not detrimentally
454 * effect performance.
457 TAILQ_REMOVE(&syncache_percpu->timerq[sc->sc_rxtslot], sc, sc_timerq);
464 * Place a timeout message on the TCP thread's message queue.
465 * This routine runs in soft interrupt context.
467 * An invariant is for this routine to be called, the callout must
468 * have been active. Note that the callout is not deactivated until
469 * after the message has been processed in syncache_timer_handler() below.
472 syncache_timer(void *p)
474 struct netmsg_sc_timer *msg = p;
476 lwkt_sendmsg(msg->nm_mrec->port, &msg->nm_netmsg.nm_lmsg);
480 * Service a timer message queued by timer expiration.
481 * This routine runs in the TCP protocol thread.
483 * Walk the timer queues, looking for SYN,ACKs that need to be retransmitted.
484 * If we have retransmitted an entry the maximum number of times, expire it.
486 * When we finish processing timed-out entries, we restart the timer if there
487 * are any entries still on the queue and deactivate it otherwise. Only after
488 * a timer has been deactivated here can it be restarted by syncache_timeout().
491 syncache_timer_handler(netmsg_t netmsg)
493 struct tcp_syncache_percpu *syncache_percpu;
494 struct syncache *sc, *nsc;
498 slot = ((struct netmsg_sc_timer *)netmsg)->nm_mrec->slot;
499 syncache_percpu = &tcp_syncache_percpu[mycpu->gd_cpuid];
502 nsc = TAILQ_FIRST(&syncache_percpu->timerq[slot]);
503 while (nsc != NULL) {
504 if (ticks < nsc->sc_rxttime)
505 break; /* finished because timerq sorted by time */
507 if (sc->sc_tp == NULL) {
508 nsc = TAILQ_NEXT(sc, sc_timerq);
509 syncache_drop(sc, NULL);
510 tcpstat.tcps_sc_stale++;
513 inp = sc->sc_tp->t_inpcb;
514 if (slot == SYNCACHE_MAXREXMTS ||
515 slot >= tcp_syncache.rexmt_limit ||
517 inp->inp_gencnt != sc->sc_inp_gencnt) {
518 nsc = TAILQ_NEXT(sc, sc_timerq);
519 syncache_drop(sc, NULL);
520 tcpstat.tcps_sc_stale++;
524 * syncache_respond() may call back into the syncache to
525 * to modify another entry, so do not obtain the next
526 * entry on the timer chain until it has completed.
528 syncache_respond(sc, NULL);
529 nsc = TAILQ_NEXT(sc, sc_timerq);
530 tcpstat.tcps_sc_retransmitted++;
531 TAILQ_REMOVE(&syncache_percpu->timerq[slot], sc, sc_timerq);
532 syncache_timeout(syncache_percpu, sc, slot + 1);
535 callout_reset(&syncache_percpu->tt_timerq[slot],
536 nsc->sc_rxttime - ticks, syncache_timer,
537 &syncache_percpu->mrec[slot]);
539 callout_deactivate(&syncache_percpu->tt_timerq[slot]);
542 lwkt_replymsg(&netmsg->nm_lmsg, 0);
546 * Find an entry in the syncache.
549 syncache_lookup(struct in_conninfo *inc, struct syncache_head **schp)
551 struct tcp_syncache_percpu *syncache_percpu;
553 struct syncache_head *sch;
555 syncache_percpu = &tcp_syncache_percpu[mycpu->gd_cpuid];
557 if (inc->inc_isipv6) {
558 sch = &syncache_percpu->hashbase[
559 SYNCACHE_HASH6(inc, tcp_syncache.hashmask)];
561 TAILQ_FOREACH(sc, &sch->sch_bucket, sc_hash)
562 if (ENDPTS6_EQ(&inc->inc_ie, &sc->sc_inc.inc_ie))
567 sch = &syncache_percpu->hashbase[
568 SYNCACHE_HASH(inc, tcp_syncache.hashmask)];
570 TAILQ_FOREACH(sc, &sch->sch_bucket, sc_hash) {
572 if (sc->sc_inc.inc_isipv6)
575 if (ENDPTS_EQ(&inc->inc_ie, &sc->sc_inc.inc_ie))
583 * This function is called when we get a RST for a
584 * non-existent connection, so that we can see if the
585 * connection is in the syn cache. If it is, zap it.
588 syncache_chkrst(struct in_conninfo *inc, struct tcphdr *th)
591 struct syncache_head *sch;
593 sc = syncache_lookup(inc, &sch);
597 * If the RST bit is set, check the sequence number to see
598 * if this is a valid reset segment.
600 * In all states except SYN-SENT, all reset (RST) segments
601 * are validated by checking their SEQ-fields. A reset is
602 * valid if its sequence number is in the window.
604 * The sequence number in the reset segment is normally an
605 * echo of our outgoing acknowlegement numbers, but some hosts
606 * send a reset with the sequence number at the rightmost edge
607 * of our receive window, and we have to handle this case.
609 if (SEQ_GEQ(th->th_seq, sc->sc_irs) &&
610 SEQ_LEQ(th->th_seq, sc->sc_irs + sc->sc_wnd)) {
611 syncache_drop(sc, sch);
612 tcpstat.tcps_sc_reset++;
617 syncache_badack(struct in_conninfo *inc)
620 struct syncache_head *sch;
622 sc = syncache_lookup(inc, &sch);
624 syncache_drop(sc, sch);
625 tcpstat.tcps_sc_badack++;
630 syncache_unreach(struct in_conninfo *inc, struct tcphdr *th)
633 struct syncache_head *sch;
635 /* we are called at splnet() here */
636 sc = syncache_lookup(inc, &sch);
640 /* If the sequence number != sc_iss, then it's a bogus ICMP msg */
641 if (ntohl(th->th_seq) != sc->sc_iss)
645 * If we've rertransmitted 3 times and this is our second error,
646 * we remove the entry. Otherwise, we allow it to continue on.
647 * This prevents us from incorrectly nuking an entry during a
648 * spurious network outage.
652 if ((sc->sc_flags & SCF_UNREACH) == 0 || sc->sc_rxtslot < 3) {
653 sc->sc_flags |= SCF_UNREACH;
656 syncache_drop(sc, sch);
657 tcpstat.tcps_sc_unreach++;
661 * Build a new TCP socket structure from a syncache entry.
663 * This is called from the context of the SYN+ACK
665 static struct socket *
666 syncache_socket(struct syncache *sc, struct socket *lso, struct mbuf *m)
668 struct inpcb *inp = NULL, *linp;
673 const boolean_t isipv6 = sc->sc_inc.inc_isipv6;
675 const boolean_t isipv6 = FALSE;
679 * Ok, create the full blown connection, and set things up
680 * as they would have been set up if we had created the
681 * connection when the SYN arrived. If we can't create
682 * the connection, abort it.
684 so = sonewconn(lso, SS_ISCONNECTED);
687 * Drop the connection; we will send a RST if the peer
688 * retransmits the ACK,
690 tcpstat.tcps_listendrop++;
695 * Set the protocol processing port for the socket to the current
696 * port (that the connection came in on).
698 sosetport(so, &curthread->td_msgport);
701 * Insert new socket into hash list.
704 inp->inp_inc.inc_isipv6 = sc->sc_inc.inc_isipv6;
706 inp->in6p_laddr = sc->sc_inc.inc6_laddr;
709 inp->inp_vflag &= ~INP_IPV6;
710 inp->inp_vflag |= INP_IPV4;
711 inp->inp_flags &= ~IN6P_IPV6_V6ONLY;
713 inp->inp_laddr = sc->sc_inc.inc_laddr;
715 inp->inp_lport = sc->sc_inc.inc_lport;
716 if (in_pcbinsporthash(inp) != 0) {
718 * Undo the assignments above if we failed to
719 * put the PCB on the hash lists.
722 inp->in6p_laddr = kin6addr_any;
724 inp->inp_laddr.s_addr = INADDR_ANY;
730 /* copy old policy into new socket's */
731 if (ipsec_copy_policy(linp->inp_sp, inp->inp_sp))
732 kprintf("syncache_expand: could not copy policy\n");
735 struct in6_addr laddr6;
736 struct sockaddr_in6 sin6;
738 * Inherit socket options from the listening socket.
739 * Note that in6p_inputopts are not (and should not be)
740 * copied, since it stores previously received options and is
741 * used to detect if each new option is different than the
742 * previous one and hence should be passed to a user.
743 * If we copied in6p_inputopts, a user would not be able to
744 * receive options just after calling the accept system call.
746 inp->inp_flags |= linp->inp_flags & INP_CONTROLOPTS;
747 if (linp->in6p_outputopts)
748 inp->in6p_outputopts =
749 ip6_copypktopts(linp->in6p_outputopts, M_INTWAIT);
750 inp->in6p_route = sc->sc_route6;
751 sc->sc_route6.ro_rt = NULL;
753 sin6.sin6_family = AF_INET6;
754 sin6.sin6_len = sizeof sin6;
755 sin6.sin6_addr = sc->sc_inc.inc6_faddr;
756 sin6.sin6_port = sc->sc_inc.inc_fport;
757 sin6.sin6_flowinfo = sin6.sin6_scope_id = 0;
758 laddr6 = inp->in6p_laddr;
759 if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
760 inp->in6p_laddr = sc->sc_inc.inc6_laddr;
761 if (in6_pcbconnect(inp, (struct sockaddr *)&sin6, &thread0)) {
762 inp->in6p_laddr = laddr6;
766 struct in_addr laddr;
767 struct sockaddr_in sin;
769 inp->inp_options = ip_srcroute(m);
770 if (inp->inp_options == NULL) {
771 inp->inp_options = sc->sc_ipopts;
772 sc->sc_ipopts = NULL;
774 inp->inp_route = sc->sc_route;
775 sc->sc_route.ro_rt = NULL;
777 sin.sin_family = AF_INET;
778 sin.sin_len = sizeof sin;
779 sin.sin_addr = sc->sc_inc.inc_faddr;
780 sin.sin_port = sc->sc_inc.inc_fport;
781 bzero(sin.sin_zero, sizeof sin.sin_zero);
782 laddr = inp->inp_laddr;
783 if (inp->inp_laddr.s_addr == INADDR_ANY)
784 inp->inp_laddr = sc->sc_inc.inc_laddr;
785 if (in_pcbconnect(inp, (struct sockaddr *)&sin, &thread0)) {
786 inp->inp_laddr = laddr;
792 * The current port should be in the context of the SYN+ACK and
793 * so should match the tcp address port.
795 * XXX we may be running on the netisr thread instead of a tcp
796 * thread, in which case port will not match
797 * curthread->td_msgport.
800 port = tcp6_addrport();
802 port = tcp_addrport(inp->inp_faddr.s_addr, inp->inp_fport,
803 inp->inp_laddr.s_addr, inp->inp_lport);
805 /*KKASSERT(port == &curthread->td_msgport);*/
808 tp->t_state = TCPS_SYN_RECEIVED;
809 tp->iss = sc->sc_iss;
810 tp->irs = sc->sc_irs;
813 tp->snd_wl1 = sc->sc_irs;
814 tp->rcv_up = sc->sc_irs + 1;
815 tp->rcv_wnd = sc->sc_wnd;
816 tp->rcv_adv += tp->rcv_wnd;
818 tp->t_flags = sototcpcb(lso)->t_flags & (TF_NOPUSH | TF_NODELAY);
819 if (sc->sc_flags & SCF_NOOPT)
820 tp->t_flags |= TF_NOOPT;
821 if (sc->sc_flags & SCF_WINSCALE) {
822 tp->t_flags |= TF_REQ_SCALE | TF_RCVD_SCALE;
823 tp->requested_s_scale = sc->sc_requested_s_scale;
824 tp->request_r_scale = sc->sc_request_r_scale;
826 if (sc->sc_flags & SCF_TIMESTAMP) {
827 tp->t_flags |= TF_REQ_TSTMP | TF_RCVD_TSTMP;
828 tp->ts_recent = sc->sc_tsrecent;
829 tp->ts_recent_age = ticks;
831 if (sc->sc_flags & SCF_SACK_PERMITTED)
832 tp->t_flags |= TF_SACK_PERMITTED;
834 tcp_mss(tp, sc->sc_peer_mss);
837 * If the SYN,ACK was retransmitted, reset cwnd to 1 segment.
839 if (sc->sc_rxtslot != 0)
840 tp->snd_cwnd = tp->t_maxseg;
841 tcp_create_timermsg(tp, port);
842 tcp_callout_reset(tp, tp->tt_keep, tcp_keepinit, tcp_timer_keep);
844 tcpstat.tcps_accepts++;
854 * This function gets called when we receive an ACK for a
855 * socket in the LISTEN state. We look up the connection
856 * in the syncache, and if its there, we pull it out of
857 * the cache and turn it into a full-blown connection in
858 * the SYN-RECEIVED state.
861 syncache_expand(struct in_conninfo *inc, struct tcphdr *th, struct socket **sop,
865 struct syncache_head *sch;
868 sc = syncache_lookup(inc, &sch);
871 * There is no syncache entry, so see if this ACK is
872 * a returning syncookie. To do this, first:
873 * A. See if this socket has had a syncache entry dropped in
874 * the past. We don't want to accept a bogus syncookie
875 * if we've never received a SYN.
876 * B. check that the syncookie is valid. If it is, then
877 * cobble up a fake syncache entry, and return.
881 sc = syncookie_lookup(inc, th, *sop);
885 tcpstat.tcps_sc_recvcookie++;
889 * If seg contains an ACK, but not for our SYN/ACK, send a RST.
891 if (th->th_ack != sc->sc_iss + 1)
894 so = syncache_socket(sc, *sop, m);
898 /* XXXjlemon check this - is this correct? */
899 tcp_respond(NULL, m, m, th,
900 th->th_seq + tlen, (tcp_seq)0, TH_RST | TH_ACK);
902 m_freem(m); /* XXX only needed for above */
903 tcpstat.tcps_sc_aborted++;
905 tcpstat.tcps_sc_completed++;
910 syncache_drop(sc, sch);
916 * Given a LISTEN socket and an inbound SYN request, add
917 * this to the syn cache, and send back a segment:
918 * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
921 * IMPORTANT NOTE: We do _NOT_ ACK data that might accompany the SYN.
922 * Doing so would require that we hold onto the data and deliver it
923 * to the application. However, if we are the target of a SYN-flood
924 * DoS attack, an attacker could send data which would eventually
925 * consume all available buffer space if it were ACKed. By not ACKing
926 * the data, we avoid this DoS scenario.
929 syncache_add(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th,
930 struct socket **sop, struct mbuf *m)
932 struct tcp_syncache_percpu *syncache_percpu;
935 struct syncache *sc = NULL;
936 struct syncache_head *sch;
937 struct mbuf *ipopts = NULL;
940 syncache_percpu = &tcp_syncache_percpu[mycpu->gd_cpuid];
945 * Remember the IP options, if any.
948 if (!inc->inc_isipv6)
950 ipopts = ip_srcroute(m);
953 * See if we already have an entry for this connection.
954 * If we do, resend the SYN,ACK, and reset the retransmit timer.
957 * The syncache should be re-initialized with the contents
958 * of the new SYN which may have different options.
960 sc = syncache_lookup(inc, &sch);
962 tcpstat.tcps_sc_dupsyn++;
965 * If we were remembering a previous source route,
966 * forget it and use the new one we've been given.
969 m_free(sc->sc_ipopts);
970 sc->sc_ipopts = ipopts;
973 * Update timestamp if present.
975 if (sc->sc_flags & SCF_TIMESTAMP)
976 sc->sc_tsrecent = to->to_tsval;
978 /* Just update the TOF_SACK_PERMITTED for now. */
979 if (tcp_do_sack && (to->to_flags & TOF_SACK_PERMITTED))
980 sc->sc_flags |= SCF_SACK_PERMITTED;
982 sc->sc_flags &= ~SCF_SACK_PERMITTED;
985 * PCB may have changed, pick up new values.
988 sc->sc_tp->t_flags &= ~TF_SYNCACHE;
989 tp->t_flags |= TF_SYNCACHE;
992 sc->sc_inp_gencnt = tp->t_inpcb->inp_gencnt;
993 if (syncache_respond(sc, m) == 0) {
995 TAILQ_REMOVE(&syncache_percpu->timerq[sc->sc_rxtslot],
998 syncache_timeout(syncache_percpu, sc, sc->sc_rxtslot);
999 tcpstat.tcps_sndacks++;
1000 tcpstat.tcps_sndtotal++;
1007 * Fill in the syncache values.
1009 sc = kmalloc(sizeof(struct syncache), M_SYNCACHE, M_WAITOK|M_ZERO);
1010 sc->sc_inp_gencnt = tp->t_inpcb->inp_gencnt;
1011 sc->sc_ipopts = ipopts;
1012 sc->sc_inc.inc_fport = inc->inc_fport;
1013 sc->sc_inc.inc_lport = inc->inc_lport;
1015 tp->t_flags |= TF_SYNCACHE;
1017 sc->sc_inc.inc_isipv6 = inc->inc_isipv6;
1018 if (inc->inc_isipv6) {
1019 sc->sc_inc.inc6_faddr = inc->inc6_faddr;
1020 sc->sc_inc.inc6_laddr = inc->inc6_laddr;
1021 sc->sc_route6.ro_rt = NULL;
1025 sc->sc_inc.inc_faddr = inc->inc_faddr;
1026 sc->sc_inc.inc_laddr = inc->inc_laddr;
1027 sc->sc_route.ro_rt = NULL;
1029 sc->sc_irs = th->th_seq;
1031 sc->sc_peer_mss = to->to_flags & TOF_MSS ? to->to_mss : 0;
1033 sc->sc_iss = syncookie_generate(sc);
1035 sc->sc_iss = karc4random();
1037 /* Initial receive window: clip ssb_space to [0 .. TCP_MAXWIN] */
1038 win = ssb_space(&so->so_rcv);
1040 win = imin(win, TCP_MAXWIN);
1043 if (tcp_do_rfc1323) {
1045 * A timestamp received in a SYN makes
1046 * it ok to send timestamp requests and replies.
1048 if (to->to_flags & TOF_TS) {
1049 sc->sc_tsrecent = to->to_tsval;
1050 sc->sc_flags |= SCF_TIMESTAMP;
1052 if (to->to_flags & TOF_SCALE) {
1053 int wscale = TCP_MIN_WINSHIFT;
1055 /* Compute proper scaling value from buffer space */
1056 while (wscale < TCP_MAX_WINSHIFT &&
1057 (TCP_MAXWIN << wscale) < so->so_rcv.ssb_hiwat) {
1060 sc->sc_request_r_scale = wscale;
1061 sc->sc_requested_s_scale = to->to_requested_s_scale;
1062 sc->sc_flags |= SCF_WINSCALE;
1065 if (tcp_do_sack && (to->to_flags & TOF_SACK_PERMITTED))
1066 sc->sc_flags |= SCF_SACK_PERMITTED;
1067 if (tp->t_flags & TF_NOOPT)
1068 sc->sc_flags = SCF_NOOPT;
1070 if (syncache_respond(sc, m) == 0) {
1071 syncache_insert(sc, sch);
1072 tcpstat.tcps_sndacks++;
1073 tcpstat.tcps_sndtotal++;
1076 tcpstat.tcps_sc_dropped++;
1083 syncache_respond(struct syncache *sc, struct mbuf *m)
1087 u_int16_t tlen, hlen, mssopt;
1088 struct ip *ip = NULL;
1091 struct ip6_hdr *ip6 = NULL;
1093 const boolean_t isipv6 = sc->sc_inc.inc_isipv6;
1095 const boolean_t isipv6 = FALSE;
1099 rt = tcp_rtlookup6(&sc->sc_inc);
1101 mssopt = rt->rt_ifp->if_mtu -
1102 (sizeof(struct ip6_hdr) + sizeof(struct tcphdr));
1104 mssopt = tcp_v6mssdflt;
1105 hlen = sizeof(struct ip6_hdr);
1107 rt = tcp_rtlookup(&sc->sc_inc);
1109 mssopt = rt->rt_ifp->if_mtu -
1110 (sizeof(struct ip) + sizeof(struct tcphdr));
1112 mssopt = tcp_mssdflt;
1113 hlen = sizeof(struct ip);
1116 /* Compute the size of the TCP options. */
1117 if (sc->sc_flags & SCF_NOOPT) {
1120 optlen = TCPOLEN_MAXSEG +
1121 ((sc->sc_flags & SCF_WINSCALE) ? 4 : 0) +
1122 ((sc->sc_flags & SCF_TIMESTAMP) ? TCPOLEN_TSTAMP_APPA : 0) +
1123 ((sc->sc_flags & SCF_SACK_PERMITTED) ?
1124 TCPOLEN_SACK_PERMITTED_ALIGNED : 0);
1126 tlen = hlen + sizeof(struct tcphdr) + optlen;
1130 * assume that the entire packet will fit in a header mbuf
1132 KASSERT(max_linkhdr + tlen <= MHLEN, ("syncache: mbuf too small"));
1135 * XXX shouldn't this reuse the mbuf if possible ?
1136 * Create the IP+TCP header from scratch.
1141 m = m_gethdr(MB_DONTWAIT, MT_HEADER);
1144 m->m_data += max_linkhdr;
1146 m->m_pkthdr.len = tlen;
1147 m->m_pkthdr.rcvif = NULL;
1150 ip6 = mtod(m, struct ip6_hdr *);
1151 ip6->ip6_vfc = IPV6_VERSION;
1152 ip6->ip6_nxt = IPPROTO_TCP;
1153 ip6->ip6_src = sc->sc_inc.inc6_laddr;
1154 ip6->ip6_dst = sc->sc_inc.inc6_faddr;
1155 ip6->ip6_plen = htons(tlen - hlen);
1156 /* ip6_hlim is set after checksum */
1157 /* ip6_flow = ??? */
1159 th = (struct tcphdr *)(ip6 + 1);
1161 ip = mtod(m, struct ip *);
1162 ip->ip_v = IPVERSION;
1163 ip->ip_hl = sizeof(struct ip) >> 2;
1168 ip->ip_p = IPPROTO_TCP;
1169 ip->ip_src = sc->sc_inc.inc_laddr;
1170 ip->ip_dst = sc->sc_inc.inc_faddr;
1171 ip->ip_ttl = sc->sc_tp->t_inpcb->inp_ip_ttl; /* XXX */
1172 ip->ip_tos = sc->sc_tp->t_inpcb->inp_ip_tos; /* XXX */
1175 * See if we should do MTU discovery. Route lookups are
1176 * expensive, so we will only unset the DF bit if:
1178 * 1) path_mtu_discovery is disabled
1179 * 2) the SCF_UNREACH flag has been set
1181 if (path_mtu_discovery
1182 && ((sc->sc_flags & SCF_UNREACH) == 0)) {
1183 ip->ip_off |= IP_DF;
1186 th = (struct tcphdr *)(ip + 1);
1188 th->th_sport = sc->sc_inc.inc_lport;
1189 th->th_dport = sc->sc_inc.inc_fport;
1191 th->th_seq = htonl(sc->sc_iss);
1192 th->th_ack = htonl(sc->sc_irs + 1);
1193 th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
1195 th->th_flags = TH_SYN | TH_ACK;
1196 th->th_win = htons(sc->sc_wnd);
1199 /* Tack on the TCP options. */
1202 optp = (u_int8_t *)(th + 1);
1203 *optp++ = TCPOPT_MAXSEG;
1204 *optp++ = TCPOLEN_MAXSEG;
1205 *optp++ = (mssopt >> 8) & 0xff;
1206 *optp++ = mssopt & 0xff;
1208 if (sc->sc_flags & SCF_WINSCALE) {
1209 *((u_int32_t *)optp) = htonl(TCPOPT_NOP << 24 |
1210 TCPOPT_WINDOW << 16 | TCPOLEN_WINDOW << 8 |
1211 sc->sc_request_r_scale);
1215 if (sc->sc_flags & SCF_TIMESTAMP) {
1216 u_int32_t *lp = (u_int32_t *)(optp);
1218 /* Form timestamp option as shown in appendix A of RFC 1323. */
1219 *lp++ = htonl(TCPOPT_TSTAMP_HDR);
1220 *lp++ = htonl(ticks);
1221 *lp = htonl(sc->sc_tsrecent);
1222 optp += TCPOLEN_TSTAMP_APPA;
1225 if (sc->sc_flags & SCF_SACK_PERMITTED) {
1226 *((u_int32_t *)optp) = htonl(TCPOPT_SACK_PERMITTED_ALIGNED);
1227 optp += TCPOLEN_SACK_PERMITTED_ALIGNED;
1232 struct route_in6 *ro6 = &sc->sc_route6;
1235 th->th_sum = in6_cksum(m, IPPROTO_TCP, hlen, tlen - hlen);
1236 ip6->ip6_hlim = in6_selecthlim(NULL,
1237 ro6->ro_rt ? ro6->ro_rt->rt_ifp : NULL);
1238 error = ip6_output(m, NULL, ro6, 0, NULL, NULL,
1239 sc->sc_tp->t_inpcb);
1241 th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
1242 htons(tlen - hlen + IPPROTO_TCP));
1243 m->m_pkthdr.csum_flags = CSUM_TCP;
1244 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
1245 error = ip_output(m, sc->sc_ipopts, &sc->sc_route,
1246 IP_DEBUGROUTE, NULL, sc->sc_tp->t_inpcb);
1254 * |. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .|
1256 * | MD5(laddr,faddr,secret,lport,fport) |. . . . . . .|
1258 * (A): peer mss index
1262 * The values below are chosen to minimize the size of the tcp_secret
1263 * table, as well as providing roughly a 16 second lifetime for the cookie.
1266 #define SYNCOOKIE_WNDBITS 5 /* exposed bits for window indexing */
1267 #define SYNCOOKIE_TIMESHIFT 1 /* scale ticks to window time units */
1269 #define SYNCOOKIE_WNDMASK ((1 << SYNCOOKIE_WNDBITS) - 1)
1270 #define SYNCOOKIE_NSECRETS (1 << SYNCOOKIE_WNDBITS)
1271 #define SYNCOOKIE_TIMEOUT \
1272 (hz * (1 << SYNCOOKIE_WNDBITS) / (1 << SYNCOOKIE_TIMESHIFT))
1273 #define SYNCOOKIE_DATAMASK ((3 << SYNCOOKIE_WNDBITS) | SYNCOOKIE_WNDMASK)
1276 u_int32_t ts_secbits[4];
1278 } tcp_secret[SYNCOOKIE_NSECRETS];
1280 static int tcp_msstab[] = { 0, 536, 1460, 8960 };
1282 static MD5_CTX syn_ctx;
1284 #define MD5Add(v) MD5Update(&syn_ctx, (u_char *)&v, sizeof(v))
1287 u_int32_t laddr, faddr;
1288 u_int32_t secbits[4];
1289 u_int16_t lport, fport;
1293 CTASSERT(sizeof(struct md5_add) == 28);
1297 * Consider the problem of a recreated (and retransmitted) cookie. If the
1298 * original SYN was accepted, the connection is established. The second
1299 * SYN is inflight, and if it arrives with an ISN that falls within the
1300 * receive window, the connection is killed.
1302 * However, since cookies have other problems, this may not be worth
1307 syncookie_generate(struct syncache *sc)
1309 u_int32_t md5_buffer[4];
1314 const boolean_t isipv6 = sc->sc_inc.inc_isipv6;
1316 const boolean_t isipv6 = FALSE;
1319 idx = ((ticks << SYNCOOKIE_TIMESHIFT) / hz) & SYNCOOKIE_WNDMASK;
1320 if (tcp_secret[idx].ts_expire < ticks) {
1321 for (i = 0; i < 4; i++)
1322 tcp_secret[idx].ts_secbits[i] = karc4random();
1323 tcp_secret[idx].ts_expire = ticks + SYNCOOKIE_TIMEOUT;
1325 for (data = sizeof(tcp_msstab) / sizeof(int) - 1; data > 0; data--)
1326 if (tcp_msstab[data] <= sc->sc_peer_mss)
1328 data = (data << SYNCOOKIE_WNDBITS) | idx;
1329 data ^= sc->sc_irs; /* peer's iss */
1332 MD5Add(sc->sc_inc.inc6_laddr);
1333 MD5Add(sc->sc_inc.inc6_faddr);
1337 add.laddr = sc->sc_inc.inc_laddr.s_addr;
1338 add.faddr = sc->sc_inc.inc_faddr.s_addr;
1340 add.lport = sc->sc_inc.inc_lport;
1341 add.fport = sc->sc_inc.inc_fport;
1342 add.secbits[0] = tcp_secret[idx].ts_secbits[0];
1343 add.secbits[1] = tcp_secret[idx].ts_secbits[1];
1344 add.secbits[2] = tcp_secret[idx].ts_secbits[2];
1345 add.secbits[3] = tcp_secret[idx].ts_secbits[3];
1347 MD5Final((u_char *)&md5_buffer, &syn_ctx);
1348 data ^= (md5_buffer[0] & ~SYNCOOKIE_WNDMASK);
1352 static struct syncache *
1353 syncookie_lookup(struct in_conninfo *inc, struct tcphdr *th, struct socket *so)
1355 u_int32_t md5_buffer[4];
1356 struct syncache *sc;
1361 data = (th->th_ack - 1) ^ (th->th_seq - 1); /* remove ISS */
1362 idx = data & SYNCOOKIE_WNDMASK;
1363 if (tcp_secret[idx].ts_expire < ticks ||
1364 sototcpcb(so)->ts_recent + SYNCOOKIE_TIMEOUT < ticks)
1368 if (inc->inc_isipv6) {
1369 MD5Add(inc->inc6_laddr);
1370 MD5Add(inc->inc6_faddr);
1376 add.laddr = inc->inc_laddr.s_addr;
1377 add.faddr = inc->inc_faddr.s_addr;
1379 add.lport = inc->inc_lport;
1380 add.fport = inc->inc_fport;
1381 add.secbits[0] = tcp_secret[idx].ts_secbits[0];
1382 add.secbits[1] = tcp_secret[idx].ts_secbits[1];
1383 add.secbits[2] = tcp_secret[idx].ts_secbits[2];
1384 add.secbits[3] = tcp_secret[idx].ts_secbits[3];
1386 MD5Final((u_char *)&md5_buffer, &syn_ctx);
1387 data ^= md5_buffer[0];
1388 if (data & ~SYNCOOKIE_DATAMASK)
1390 data = data >> SYNCOOKIE_WNDBITS;
1393 * Fill in the syncache values.
1394 * XXX duplicate code from syncache_add
1396 sc = kmalloc(sizeof(struct syncache), M_SYNCACHE, M_WAITOK|M_ZERO);
1397 sc->sc_ipopts = NULL;
1398 sc->sc_inc.inc_fport = inc->inc_fport;
1399 sc->sc_inc.inc_lport = inc->inc_lport;
1401 sc->sc_inc.inc_isipv6 = inc->inc_isipv6;
1402 if (inc->inc_isipv6) {
1403 sc->sc_inc.inc6_faddr = inc->inc6_faddr;
1404 sc->sc_inc.inc6_laddr = inc->inc6_laddr;
1405 sc->sc_route6.ro_rt = NULL;
1409 sc->sc_inc.inc_faddr = inc->inc_faddr;
1410 sc->sc_inc.inc_laddr = inc->inc_laddr;
1411 sc->sc_route.ro_rt = NULL;
1413 sc->sc_irs = th->th_seq - 1;
1414 sc->sc_iss = th->th_ack - 1;
1415 wnd = ssb_space(&so->so_rcv);
1417 wnd = imin(wnd, TCP_MAXWIN);
1421 sc->sc_peer_mss = tcp_msstab[data];