2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include "opt_compat.h"
37 #include "opt_inet6.h"
38 #include "opt_ipsec.h"
39 #include "opt_tcpdebug.h"
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/callout.h>
44 #include <sys/hhook.h>
45 #include <sys/kernel.h>
46 #include <sys/khelp.h>
47 #include <sys/sysctl.h>
49 #include <sys/malloc.h>
52 #include <sys/domain.h>
56 #include <sys/socket.h>
57 #include <sys/socketvar.h>
58 #include <sys/protosw.h>
59 #include <sys/random.h>
63 #include <net/route.h>
67 #include <netinet/cc.h>
68 #include <netinet/in.h>
69 #include <netinet/in_pcb.h>
70 #include <netinet/in_systm.h>
71 #include <netinet/in_var.h>
72 #include <netinet/ip.h>
73 #include <netinet/ip_icmp.h>
74 #include <netinet/ip_var.h>
76 #include <netinet/ip6.h>
77 #include <netinet6/in6_pcb.h>
78 #include <netinet6/ip6_var.h>
79 #include <netinet6/scope6_var.h>
80 #include <netinet6/nd6.h>
83 #include <netinet/tcp_fsm.h>
84 #include <netinet/tcp_seq.h>
85 #include <netinet/tcp_timer.h>
86 #include <netinet/tcp_var.h>
87 #include <netinet/tcp_syncache.h>
88 #include <netinet/tcp_offload.h>
90 #include <netinet6/tcp6_var.h>
92 #include <netinet/tcpip.h>
94 #include <netinet/tcp_debug.h>
97 #include <netinet6/ip6protosw.h>
101 #include <netipsec/ipsec.h>
102 #include <netipsec/xform.h>
104 #include <netipsec/ipsec6.h>
106 #include <netipsec/key.h>
107 #include <sys/syslog.h>
110 #include <machine/in_cksum.h>
113 #include <security/mac/mac_framework.h>
115 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS;
117 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS;
121 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
126 error = sysctl_handle_int(oidp, &new, 0, req);
127 if (error == 0 && req->newptr) {
128 if (new < TCP_MINMSS)
136 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
137 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_mssdflt), 0,
138 &sysctl_net_inet_tcp_mss_check, "I",
139 "Default TCP Maximum Segment Size");
143 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS)
147 new = V_tcp_v6mssdflt;
148 error = sysctl_handle_int(oidp, &new, 0, req);
149 if (error == 0 && req->newptr) {
150 if (new < TCP_MINMSS)
153 V_tcp_v6mssdflt = new;
158 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
159 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_v6mssdflt), 0,
160 &sysctl_net_inet_tcp_mss_v6_check, "I",
161 "Default TCP Maximum Segment Size for IPv6");
165 * Minimum MSS we accept and use. This prevents DoS attacks where
166 * we are forced to a ridiculous low MSS like 20 and send hundreds
167 * of packets instead of one. The effect scales with the available
168 * bandwidth and quickly saturates the CPU and network interface
169 * with packet generation and sending. Set to zero to disable MINMSS
170 * checking. This setting prevents us from sending too small packets.
172 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS;
173 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW,
174 &VNET_NAME(tcp_minmss), 0,
175 "Minmum TCP Maximum Segment Size");
177 VNET_DEFINE(int, tcp_do_rfc1323) = 1;
178 SYSCTL_VNET_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
179 &VNET_NAME(tcp_do_rfc1323), 0,
180 "Enable rfc1323 (high performance TCP) extensions");
182 static int tcp_log_debug = 0;
183 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW,
184 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments");
186 static int tcp_tcbhashsize = 0;
187 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN,
188 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
190 static int do_tcpdrain = 1;
191 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
192 "Enable tcp_drain routine for extra help when low on mbufs");
194 SYSCTL_VNET_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
195 &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
197 static VNET_DEFINE(int, icmp_may_rst) = 1;
198 #define V_icmp_may_rst VNET(icmp_may_rst)
199 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW,
200 &VNET_NAME(icmp_may_rst), 0,
201 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
203 static VNET_DEFINE(int, tcp_isn_reseed_interval) = 0;
204 #define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval)
205 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
206 &VNET_NAME(tcp_isn_reseed_interval), 0,
207 "Seconds between reseeding of ISN secret");
209 static int tcp_soreceive_stream = 0;
210 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
211 &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
214 static int tcp_sig_checksigs = 1;
215 SYSCTL_INT(_net_inet_tcp, OID_AUTO, signature_verify_input, CTLFLAG_RW,
216 &tcp_sig_checksigs, 0, "Verify RFC2385 digests on inbound traffic");
219 VNET_DEFINE(uma_zone_t, sack_hole_zone);
220 #define V_sack_hole_zone VNET(sack_hole_zone)
222 VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]);
224 static struct inpcb *tcp_notify(struct inpcb *, int);
225 static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th,
226 void *ip4hdr, const void *ip6hdr);
229 * Target size of TCP PCB hash tables. Must be a power of two.
231 * Note that this can be overridden by the kernel environment
232 * variable net.inet.tcp.tcbhashsize
235 #define TCBHASHSIZE 512
240 * Callouts should be moved into struct tcp directly. They are currently
241 * separate because the tcpcb structure is exported to userland for sysctl
242 * parsing purposes, which do not know about callouts.
251 static VNET_DEFINE(uma_zone_t, tcpcb_zone);
252 #define V_tcpcb_zone VNET(tcpcb_zone)
254 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
255 static struct mtx isn_mtx;
257 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF)
258 #define ISN_LOCK() mtx_lock(&isn_mtx)
259 #define ISN_UNLOCK() mtx_unlock(&isn_mtx)
262 * TCP initialization.
265 tcp_zone_change(void *tag)
268 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets);
269 uma_zone_set_max(V_tcpcb_zone, maxsockets);
270 tcp_tw_zone_change();
274 tcp_inpcb_init(void *mem, int size, int flags)
276 struct inpcb *inp = mem;
278 INP_LOCK_INIT(inp, "inp", "tcpinp");
287 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN,
288 &V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
289 printf("%s: WARNING: unable to register helper hook\n", __func__);
290 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT,
291 &V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
292 printf("%s: WARNING: unable to register helper hook\n", __func__);
294 hashsize = TCBHASHSIZE;
295 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
296 if (!powerof2(hashsize)) {
297 printf("WARNING: TCB hash size not a power of 2\n");
298 hashsize = 512; /* safe default */
300 in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize,
301 "tcp_inpcb", tcp_inpcb_init, NULL, UMA_ZONE_NOFREE,
302 IPI_HASHFIELDS_4TUPLE);
305 * These have to be type stable for the benefit of the timers.
307 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
308 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
309 uma_zone_set_max(V_tcpcb_zone, maxsockets);
316 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
317 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
318 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
320 /* Skip initialization of globals for non-default instances. */
321 if (!IS_DEFAULT_VNET(curvnet))
324 /* XXX virtualize those bellow? */
325 tcp_delacktime = TCPTV_DELACK;
326 tcp_keepinit = TCPTV_KEEP_INIT;
327 tcp_keepidle = TCPTV_KEEP_IDLE;
328 tcp_keepintvl = TCPTV_KEEPINTVL;
329 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
331 tcp_rexmit_min = TCPTV_MIN;
332 if (tcp_rexmit_min < 1)
334 tcp_rexmit_slop = TCPTV_CPU_VAR;
335 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
336 tcp_tcbhashsize = hashsize;
338 TUNABLE_INT_FETCH("net.inet.tcp.soreceive_stream", &tcp_soreceive_stream);
339 if (tcp_soreceive_stream) {
341 tcp_usrreqs.pru_soreceive = soreceive_stream;
344 tcp6_usrreqs.pru_soreceive = soreceive_stream;
349 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
351 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
353 if (max_protohdr < TCP_MINPROTOHDR)
354 max_protohdr = TCP_MINPROTOHDR;
355 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
357 #undef TCP_MINPROTOHDR
360 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
361 SHUTDOWN_PRI_DEFAULT);
362 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL,
363 EVENTHANDLER_PRI_ANY);
375 in_pcbinfo_destroy(&V_tcbinfo);
376 uma_zdestroy(V_sack_hole_zone);
377 uma_zdestroy(V_tcpcb_zone);
388 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
389 * tcp_template used to store this data in mbufs, but we now recopy it out
390 * of the tcpcb each time to conserve mbufs.
393 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr)
395 struct tcphdr *th = (struct tcphdr *)tcp_ptr;
397 INP_WLOCK_ASSERT(inp);
400 if ((inp->inp_vflag & INP_IPV6) != 0) {
403 ip6 = (struct ip6_hdr *)ip_ptr;
404 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
405 (inp->inp_flow & IPV6_FLOWINFO_MASK);
406 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
407 (IPV6_VERSION & IPV6_VERSION_MASK);
408 ip6->ip6_nxt = IPPROTO_TCP;
409 ip6->ip6_plen = htons(sizeof(struct tcphdr));
410 ip6->ip6_src = inp->in6p_laddr;
411 ip6->ip6_dst = inp->in6p_faddr;
414 #if defined(INET6) && defined(INET)
421 ip = (struct ip *)ip_ptr;
422 ip->ip_v = IPVERSION;
424 ip->ip_tos = inp->inp_ip_tos;
428 ip->ip_ttl = inp->inp_ip_ttl;
430 ip->ip_p = IPPROTO_TCP;
431 ip->ip_src = inp->inp_laddr;
432 ip->ip_dst = inp->inp_faddr;
435 th->th_sport = inp->inp_lport;
436 th->th_dport = inp->inp_fport;
444 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */
448 * Create template to be used to send tcp packets on a connection.
449 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
450 * use for this function is in keepalives, which use tcp_respond.
453 tcpip_maketemplate(struct inpcb *inp)
457 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT);
460 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t);
465 * Send a single message to the TCP at address specified by
466 * the given TCP/IP header. If m == NULL, then we make a copy
467 * of the tcpiphdr at ti and send directly to the addressed host.
468 * This is used to force keep alive messages out using the TCP
469 * template for a connection. If flags are given then we send
470 * a message back to the TCP which originated the * segment ti,
471 * and discard the mbuf containing it and any other attached mbufs.
473 * In any case the ack and sequence number of the transmitted
474 * segment are as specified by the parameters.
476 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
479 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
480 tcp_seq ack, tcp_seq seq, int flags)
493 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
496 isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4);
503 KASSERT(inp != NULL, ("tcp control block w/o inpcb"));
504 INP_WLOCK_ASSERT(inp);
509 if (!(flags & TH_RST)) {
510 win = sbspace(&inp->inp_socket->so_rcv);
511 if (win > (long)TCP_MAXWIN << tp->rcv_scale)
512 win = (long)TCP_MAXWIN << tp->rcv_scale;
516 m = m_gethdr(M_DONTWAIT, MT_DATA);
520 m->m_data += max_linkhdr;
523 bcopy((caddr_t)ip6, mtod(m, caddr_t),
524 sizeof(struct ip6_hdr));
525 ip6 = mtod(m, struct ip6_hdr *);
526 nth = (struct tcphdr *)(ip6 + 1);
530 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
531 ip = mtod(m, struct ip *);
532 nth = (struct tcphdr *)(ip + 1);
534 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
539 * XXX MRT We inherrit the FIB, which is lucky.
543 m->m_data = (caddr_t)ipgen;
545 /* m_len is set later */
547 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
550 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
551 nth = (struct tcphdr *)(ip6 + 1);
555 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
556 nth = (struct tcphdr *)(ip + 1);
560 * this is usually a case when an extension header
561 * exists between the IPv6 header and the
564 nth->th_sport = th->th_sport;
565 nth->th_dport = th->th_dport;
567 xchg(nth->th_dport, nth->th_sport, uint16_t);
573 ip6->ip6_vfc = IPV6_VERSION;
574 ip6->ip6_nxt = IPPROTO_TCP;
575 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) +
577 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
580 #if defined(INET) && defined(INET6)
585 tlen += sizeof (struct tcpiphdr);
587 ip->ip_ttl = V_ip_defttl;
588 if (V_path_mtu_discovery)
593 m->m_pkthdr.len = tlen;
594 m->m_pkthdr.rcvif = NULL;
598 * Packet is associated with a socket, so allow the
599 * label of the response to reflect the socket label.
601 INP_WLOCK_ASSERT(inp);
602 mac_inpcb_create_mbuf(inp, m);
605 * Packet is not associated with a socket, so possibly
606 * update the label in place.
608 mac_netinet_tcp_reply(m);
611 nth->th_seq = htonl(seq);
612 nth->th_ack = htonl(ack);
614 nth->th_off = sizeof (struct tcphdr) >> 2;
615 nth->th_flags = flags;
617 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
619 nth->th_win = htons((u_short)win);
624 nth->th_sum = in6_cksum(m, IPPROTO_TCP,
625 sizeof(struct ip6_hdr),
626 tlen - sizeof(struct ip6_hdr));
627 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb :
631 #if defined(INET6) && defined(INET)
636 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
637 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
638 m->m_pkthdr.csum_flags = CSUM_TCP;
639 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
643 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
644 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
648 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp);
650 #if defined(INET) && defined(INET6)
654 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp);
659 * Create a new TCP control block, making an
660 * empty reassembly queue and hooking it to the argument
661 * protocol control block. The `inp' parameter must have
662 * come from the zone allocator set up in tcp_init().
665 tcp_newtcpcb(struct inpcb *inp)
667 struct tcpcb_mem *tm;
670 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
673 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO);
678 /* Initialise cc_var struct for this tcpcb. */
680 tp->ccv->type = IPPROTO_TCP;
681 tp->ccv->ccvc.tcp = tp;
684 * Use the current system default CC algorithm.
687 KASSERT(!STAILQ_EMPTY(&cc_list), ("cc_list is empty!"));
688 CC_ALGO(tp) = CC_DEFAULT();
691 if (CC_ALGO(tp)->cb_init != NULL)
692 if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) {
693 uma_zfree(V_tcpcb_zone, tm);
698 if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) {
699 uma_zfree(V_tcpcb_zone, tm);
704 tp->t_vnet = inp->inp_vnet;
706 tp->t_timers = &tm->tt;
707 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */
708 tp->t_maxseg = tp->t_maxopd =
710 isipv6 ? V_tcp_v6mssdflt :
714 /* Set up our timeouts. */
715 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE);
716 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE);
717 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE);
718 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE);
719 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE);
721 if (V_tcp_do_rfc1323)
722 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
724 tp->t_flags |= TF_SACK_PERMIT;
725 TAILQ_INIT(&tp->snd_holes);
726 tp->t_inpcb = inp; /* XXX */
728 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
729 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
730 * reasonable initial retransmit time.
732 tp->t_srtt = TCPTV_SRTTBASE;
733 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
734 tp->t_rttmin = tcp_rexmit_min;
735 tp->t_rxtcur = TCPTV_RTOBASE;
736 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
737 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
738 tp->t_rcvtime = ticks;
740 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
741 * because the socket may be bound to an IPv6 wildcard address,
742 * which may match an IPv4-mapped IPv6 address.
744 inp->inp_ip_ttl = V_ip_defttl;
746 return (tp); /* XXX */
750 * Switch the congestion control algorithm back to NewReno for any active
751 * control blocks using an algorithm which is about to go away.
752 * This ensures the CC framework can allow the unload to proceed without leaving
753 * any dangling pointers which would trigger a panic.
754 * Returning non-zero would inform the CC framework that something went wrong
755 * and it would be unsafe to allow the unload to proceed. However, there is no
756 * way for this to occur with this implementation so we always return zero.
759 tcp_ccalgounload(struct cc_algo *unload_algo)
761 struct cc_algo *tmpalgo;
764 VNET_ITERATOR_DECL(vnet_iter);
767 * Check all active control blocks across all network stacks and change
768 * any that are using "unload_algo" back to NewReno. If "unload_algo"
769 * requires cleanup code to be run, call it.
772 VNET_FOREACH(vnet_iter) {
773 CURVNET_SET(vnet_iter);
774 INP_INFO_RLOCK(&V_tcbinfo);
776 * New connections already part way through being initialised
777 * with the CC algo we're removing will not race with this code
778 * because the INP_INFO_WLOCK is held during initialisation. We
779 * therefore don't enter the loop below until the connection
780 * list has stabilised.
782 LIST_FOREACH(inp, &V_tcb, inp_list) {
784 /* Important to skip tcptw structs. */
785 if (!(inp->inp_flags & INP_TIMEWAIT) &&
786 (tp = intotcpcb(inp)) != NULL) {
788 * By holding INP_WLOCK here, we are assured
789 * that the connection is not currently
790 * executing inside the CC module's functions
791 * i.e. it is safe to make the switch back to
794 if (CC_ALGO(tp) == unload_algo) {
795 tmpalgo = CC_ALGO(tp);
796 /* NewReno does not require any init. */
797 CC_ALGO(tp) = &newreno_cc_algo;
798 if (tmpalgo->cb_destroy != NULL)
799 tmpalgo->cb_destroy(tp->ccv);
804 INP_INFO_RUNLOCK(&V_tcbinfo);
813 * Drop a TCP connection, reporting
814 * the specified error. If connection is synchronized,
815 * then send a RST to peer.
818 tcp_drop(struct tcpcb *tp, int errno)
820 struct socket *so = tp->t_inpcb->inp_socket;
822 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
823 INP_WLOCK_ASSERT(tp->t_inpcb);
825 if (TCPS_HAVERCVDSYN(tp->t_state)) {
826 tp->t_state = TCPS_CLOSED;
827 (void) tcp_output_reset(tp);
828 TCPSTAT_INC(tcps_drops);
830 TCPSTAT_INC(tcps_conndrops);
831 if (errno == ETIMEDOUT && tp->t_softerror)
832 errno = tp->t_softerror;
833 so->so_error = errno;
834 return (tcp_close(tp));
838 tcp_discardcb(struct tcpcb *tp)
840 struct inpcb *inp = tp->t_inpcb;
841 struct socket *so = inp->inp_socket;
843 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
846 INP_WLOCK_ASSERT(inp);
849 * Make sure that all of our timers are stopped before we delete the
852 * XXXRW: Really, we would like to use callout_drain() here in order
853 * to avoid races experienced in tcp_timer.c where a timer is already
854 * executing at this point. However, we can't, both because we're
855 * running in a context where we can't sleep, and also because we
856 * hold locks required by the timers. What we instead need to do is
857 * test to see if callout_drain() is required, and if so, defer some
858 * portion of the remainder of tcp_discardcb() to an asynchronous
859 * context that can callout_drain() and then continue. Some care
860 * will be required to ensure that no further processing takes place
861 * on the tcpcb, even though it hasn't been freed (a flag?).
863 callout_stop(&tp->t_timers->tt_rexmt);
864 callout_stop(&tp->t_timers->tt_persist);
865 callout_stop(&tp->t_timers->tt_keep);
866 callout_stop(&tp->t_timers->tt_2msl);
867 callout_stop(&tp->t_timers->tt_delack);
870 * If we got enough samples through the srtt filter,
871 * save the rtt and rttvar in the routing entry.
872 * 'Enough' is arbitrarily defined as 4 rtt samples.
873 * 4 samples is enough for the srtt filter to converge
874 * to within enough % of the correct value; fewer samples
875 * and we could save a bogus rtt. The danger is not high
876 * as tcp quickly recovers from everything.
877 * XXX: Works very well but needs some more statistics!
879 if (tp->t_rttupdated >= 4) {
880 struct hc_metrics_lite metrics;
883 bzero(&metrics, sizeof(metrics));
885 * Update the ssthresh always when the conditions below
886 * are satisfied. This gives us better new start value
887 * for the congestion avoidance for new connections.
888 * ssthresh is only set if packet loss occured on a session.
890 * XXXRW: 'so' may be NULL here, and/or socket buffer may be
891 * being torn down. Ideally this code would not use 'so'.
893 ssthresh = tp->snd_ssthresh;
894 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) {
896 * convert the limit from user data bytes to
897 * packets then to packet data bytes.
899 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg;
902 ssthresh *= (u_long)(tp->t_maxseg +
904 (isipv6 ? sizeof (struct ip6_hdr) +
905 sizeof (struct tcphdr) :
907 sizeof (struct tcpiphdr)
914 metrics.rmx_ssthresh = ssthresh;
916 metrics.rmx_rtt = tp->t_srtt;
917 metrics.rmx_rttvar = tp->t_rttvar;
918 metrics.rmx_cwnd = tp->snd_cwnd;
919 metrics.rmx_sendpipe = 0;
920 metrics.rmx_recvpipe = 0;
922 tcp_hc_update(&inp->inp_inc, &metrics);
925 /* free the reassembly queue, if any */
927 /* Disconnect offload device, if any. */
928 tcp_offload_detach(tp);
930 tcp_free_sackholes(tp);
932 /* Allow the CC algorithm to clean up after itself. */
933 if (CC_ALGO(tp)->cb_destroy != NULL)
934 CC_ALGO(tp)->cb_destroy(tp->ccv);
936 khelp_destroy_osd(tp->osd);
939 inp->inp_ppcb = NULL;
941 uma_zfree(V_tcpcb_zone, tp);
945 * Attempt to close a TCP control block, marking it as dropped, and freeing
946 * the socket if we hold the only reference.
949 tcp_close(struct tcpcb *tp)
951 struct inpcb *inp = tp->t_inpcb;
954 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
955 INP_WLOCK_ASSERT(inp);
957 /* Notify any offload devices of listener close */
958 if (tp->t_state == TCPS_LISTEN)
959 tcp_offload_listen_close(tp);
961 TCPSTAT_INC(tcps_closed);
962 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
963 so = inp->inp_socket;
964 soisdisconnected(so);
965 if (inp->inp_flags & INP_SOCKREF) {
966 KASSERT(so->so_state & SS_PROTOREF,
967 ("tcp_close: !SS_PROTOREF"));
968 inp->inp_flags &= ~INP_SOCKREF;
972 so->so_state &= ~SS_PROTOREF;
982 VNET_ITERATOR_DECL(vnet_iter);
987 VNET_LIST_RLOCK_NOSLEEP();
988 VNET_FOREACH(vnet_iter) {
989 CURVNET_SET(vnet_iter);
994 * Walk the tcpbs, if existing, and flush the reassembly queue,
996 * XXX: The "Net/3" implementation doesn't imply that the TCP
997 * reassembly queue should be flushed, but in a situation
998 * where we're really low on mbufs, this is potentially
1001 INP_INFO_RLOCK(&V_tcbinfo);
1002 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) {
1003 if (inpb->inp_flags & INP_TIMEWAIT)
1006 if ((tcpb = intotcpcb(inpb)) != NULL) {
1007 tcp_reass_flush(tcpb);
1008 tcp_clean_sackreport(tcpb);
1012 INP_INFO_RUNLOCK(&V_tcbinfo);
1015 VNET_LIST_RUNLOCK_NOSLEEP();
1019 * Notify a tcp user of an asynchronous error;
1020 * store error as soft error, but wake up user
1021 * (for now, won't do anything until can select for soft error).
1023 * Do not wake up user since there currently is no mechanism for
1024 * reporting soft errors (yet - a kqueue filter may be added).
1026 static struct inpcb *
1027 tcp_notify(struct inpcb *inp, int error)
1031 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
1032 INP_WLOCK_ASSERT(inp);
1034 if ((inp->inp_flags & INP_TIMEWAIT) ||
1035 (inp->inp_flags & INP_DROPPED))
1038 tp = intotcpcb(inp);
1039 KASSERT(tp != NULL, ("tcp_notify: tp == NULL"));
1042 * Ignore some errors if we are hooked up.
1043 * If connection hasn't completed, has retransmitted several times,
1044 * and receives a second error, give up now. This is better
1045 * than waiting a long time to establish a connection that
1046 * can never complete.
1048 if (tp->t_state == TCPS_ESTABLISHED &&
1049 (error == EHOSTUNREACH || error == ENETUNREACH ||
1050 error == EHOSTDOWN)) {
1052 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
1054 tp = tcp_drop(tp, error);
1060 tp->t_softerror = error;
1064 wakeup( &so->so_timeo);
1071 tcp_pcblist(SYSCTL_HANDLER_ARGS)
1073 int error, i, m, n, pcb_count;
1074 struct inpcb *inp, **inp_list;
1079 * The process of preparing the TCB list is too time-consuming and
1080 * resource-intensive to repeat twice on every request.
1082 if (req->oldptr == NULL) {
1083 n = V_tcbinfo.ipi_count + syncache_pcbcount();
1084 n += imax(n / 8, 10);
1085 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
1089 if (req->newptr != NULL)
1093 * OK, now we're committed to doing something.
1095 INP_INFO_RLOCK(&V_tcbinfo);
1096 gencnt = V_tcbinfo.ipi_gencnt;
1097 n = V_tcbinfo.ipi_count;
1098 INP_INFO_RUNLOCK(&V_tcbinfo);
1100 m = syncache_pcbcount();
1102 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
1103 + (n + m) * sizeof(struct xtcpcb));
1107 xig.xig_len = sizeof xig;
1108 xig.xig_count = n + m;
1109 xig.xig_gen = gencnt;
1110 xig.xig_sogen = so_gencnt;
1111 error = SYSCTL_OUT(req, &xig, sizeof xig);
1115 error = syncache_pcblist(req, m, &pcb_count);
1119 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
1120 if (inp_list == NULL)
1123 INP_INFO_RLOCK(&V_tcbinfo);
1124 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0;
1125 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) {
1127 if (inp->inp_gencnt <= gencnt) {
1129 * XXX: This use of cr_cansee(), introduced with
1130 * TCP state changes, is not quite right, but for
1131 * now, better than nothing.
1133 if (inp->inp_flags & INP_TIMEWAIT) {
1134 if (intotw(inp) != NULL)
1135 error = cr_cansee(req->td->td_ucred,
1136 intotw(inp)->tw_cred);
1138 error = EINVAL; /* Skip this inp. */
1140 error = cr_canseeinpcb(req->td->td_ucred, inp);
1143 inp_list[i++] = inp;
1148 INP_INFO_RUNLOCK(&V_tcbinfo);
1152 for (i = 0; i < n; i++) {
1155 if (inp->inp_gencnt <= gencnt) {
1159 bzero(&xt, sizeof(xt));
1160 xt.xt_len = sizeof xt;
1161 /* XXX should avoid extra copy */
1162 bcopy(inp, &xt.xt_inp, sizeof *inp);
1163 inp_ppcb = inp->inp_ppcb;
1164 if (inp_ppcb == NULL)
1165 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
1166 else if (inp->inp_flags & INP_TIMEWAIT) {
1167 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
1168 xt.xt_tp.t_state = TCPS_TIME_WAIT;
1170 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
1171 if (xt.xt_tp.t_timers)
1172 tcp_timer_to_xtimer(&xt.xt_tp, xt.xt_tp.t_timers, &xt.xt_timer);
1174 if (inp->inp_socket != NULL)
1175 sotoxsocket(inp->inp_socket, &xt.xt_socket);
1177 bzero(&xt.xt_socket, sizeof xt.xt_socket);
1178 xt.xt_socket.xso_protocol = IPPROTO_TCP;
1180 xt.xt_inp.inp_gencnt = inp->inp_gencnt;
1182 error = SYSCTL_OUT(req, &xt, sizeof xt);
1186 INP_INFO_WLOCK(&V_tcbinfo);
1187 for (i = 0; i < n; i++) {
1190 if (!in_pcbrele_rlocked(inp))
1193 INP_INFO_WUNLOCK(&V_tcbinfo);
1197 * Give the user an updated idea of our state.
1198 * If the generation differs from what we told
1199 * her before, she knows that something happened
1200 * while we were processing this request, and it
1201 * might be necessary to retry.
1203 INP_INFO_RLOCK(&V_tcbinfo);
1204 xig.xig_gen = V_tcbinfo.ipi_gencnt;
1205 xig.xig_sogen = so_gencnt;
1206 xig.xig_count = V_tcbinfo.ipi_count + pcb_count;
1207 INP_INFO_RUNLOCK(&V_tcbinfo);
1208 error = SYSCTL_OUT(req, &xig, sizeof xig);
1210 free(inp_list, M_TEMP);
1214 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist,
1215 CTLTYPE_OPAQUE | CTLFLAG_RD, NULL, 0,
1216 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
1220 tcp_getcred(SYSCTL_HANDLER_ARGS)
1223 struct sockaddr_in addrs[2];
1227 error = priv_check(req->td, PRIV_NETINET_GETCRED);
1230 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1233 inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
1234 addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL);
1236 if (inp->inp_socket == NULL)
1239 error = cr_canseeinpcb(req->td->td_ucred, inp);
1241 cru2x(inp->inp_cred, &xuc);
1246 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1250 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
1251 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1252 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection");
1257 tcp6_getcred(SYSCTL_HANDLER_ARGS)
1260 struct sockaddr_in6 addrs[2];
1267 error = priv_check(req->td, PRIV_NETINET_GETCRED);
1270 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1273 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
1274 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
1277 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
1279 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
1288 inp = in_pcblookup(&V_tcbinfo,
1289 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
1291 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
1292 addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL);
1295 inp = in6_pcblookup(&V_tcbinfo,
1296 &addrs[1].sin6_addr, addrs[1].sin6_port,
1297 &addrs[0].sin6_addr, addrs[0].sin6_port,
1298 INPLOOKUP_RLOCKPCB, NULL);
1300 if (inp->inp_socket == NULL)
1303 error = cr_canseeinpcb(req->td->td_ucred, inp);
1305 cru2x(inp->inp_cred, &xuc);
1310 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1314 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
1315 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1316 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection");
1322 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
1324 struct ip *ip = vip;
1326 struct in_addr faddr;
1329 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1331 struct in_conninfo inc;
1332 tcp_seq icmp_tcp_seq;
1335 faddr = ((struct sockaddr_in *)sa)->sin_addr;
1336 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
1339 if (cmd == PRC_MSGSIZE)
1340 notify = tcp_mtudisc;
1341 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
1342 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip)
1343 notify = tcp_drop_syn_sent;
1345 * Redirects don't need to be handled up here.
1347 else if (PRC_IS_REDIRECT(cmd))
1350 * Source quench is depreciated.
1352 else if (cmd == PRC_QUENCH)
1355 * Hostdead is ugly because it goes linearly through all PCBs.
1356 * XXX: We never get this from ICMP, otherwise it makes an
1357 * excellent DoS attack on machines with many connections.
1359 else if (cmd == PRC_HOSTDEAD)
1361 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
1364 icp = (struct icmp *)((caddr_t)ip
1365 - offsetof(struct icmp, icmp_ip));
1366 th = (struct tcphdr *)((caddr_t)ip
1367 + (ip->ip_hl << 2));
1368 INP_INFO_WLOCK(&V_tcbinfo);
1369 inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport,
1370 ip->ip_src, th->th_sport, INPLOOKUP_WLOCKPCB, NULL);
1372 if (!(inp->inp_flags & INP_TIMEWAIT) &&
1373 !(inp->inp_flags & INP_DROPPED) &&
1374 !(inp->inp_socket == NULL)) {
1375 icmp_tcp_seq = htonl(th->th_seq);
1376 tp = intotcpcb(inp);
1377 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) &&
1378 SEQ_LT(icmp_tcp_seq, tp->snd_max)) {
1379 if (cmd == PRC_MSGSIZE) {
1382 * If we got a needfrag set the MTU
1383 * in the route to the suggested new
1384 * value (if given) and then notify.
1386 bzero(&inc, sizeof(inc));
1387 inc.inc_faddr = faddr;
1389 inp->inp_inc.inc_fibnum;
1391 mtu = ntohs(icp->icmp_nextmtu);
1393 * If no alternative MTU was
1394 * proposed, try the next smaller
1395 * one. ip->ip_len has already
1396 * been swapped in icmp_input().
1399 mtu = ip_next_mtu(ip->ip_len,
1401 if (mtu < V_tcp_minmss
1402 + sizeof(struct tcpiphdr))
1404 + sizeof(struct tcpiphdr);
1406 * Only cache the MTU if it
1407 * is smaller than the interface
1408 * or route MTU. tcp_mtudisc()
1409 * will do right thing by itself.
1411 if (mtu <= tcp_maxmtu(&inc, NULL))
1412 tcp_hc_updatemtu(&inc, mtu);
1415 inp = (*notify)(inp, inetctlerrmap[cmd]);
1421 bzero(&inc, sizeof(inc));
1422 inc.inc_fport = th->th_dport;
1423 inc.inc_lport = th->th_sport;
1424 inc.inc_faddr = faddr;
1425 inc.inc_laddr = ip->ip_src;
1426 syncache_unreach(&inc, th);
1428 INP_INFO_WUNLOCK(&V_tcbinfo);
1430 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify);
1436 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
1439 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1440 struct ip6_hdr *ip6;
1442 struct ip6ctlparam *ip6cp = NULL;
1443 const struct sockaddr_in6 *sa6_src = NULL;
1445 struct tcp_portonly {
1450 if (sa->sa_family != AF_INET6 ||
1451 sa->sa_len != sizeof(struct sockaddr_in6))
1454 if (cmd == PRC_MSGSIZE)
1455 notify = tcp_mtudisc;
1456 else if (!PRC_IS_REDIRECT(cmd) &&
1457 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
1459 /* Source quench is depreciated. */
1460 else if (cmd == PRC_QUENCH)
1463 /* if the parameter is from icmp6, decode it. */
1465 ip6cp = (struct ip6ctlparam *)d;
1467 ip6 = ip6cp->ip6c_ip6;
1468 off = ip6cp->ip6c_off;
1469 sa6_src = ip6cp->ip6c_src;
1473 off = 0; /* fool gcc */
1478 struct in_conninfo inc;
1480 * XXX: We assume that when IPV6 is non NULL,
1481 * M and OFF are valid.
1484 /* check if we can safely examine src and dst ports */
1485 if (m->m_pkthdr.len < off + sizeof(*thp))
1488 bzero(&th, sizeof(th));
1489 m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
1491 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport,
1492 (struct sockaddr *)ip6cp->ip6c_src,
1493 th.th_sport, cmd, NULL, notify);
1495 bzero(&inc, sizeof(inc));
1496 inc.inc_fport = th.th_dport;
1497 inc.inc_lport = th.th_sport;
1498 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
1499 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
1500 inc.inc_flags |= INC_ISIPV6;
1501 INP_INFO_WLOCK(&V_tcbinfo);
1502 syncache_unreach(&inc, &th);
1503 INP_INFO_WUNLOCK(&V_tcbinfo);
1505 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src,
1506 0, cmd, NULL, notify);
1512 * Following is where TCP initial sequence number generation occurs.
1514 * There are two places where we must use initial sequence numbers:
1515 * 1. In SYN-ACK packets.
1516 * 2. In SYN packets.
1518 * All ISNs for SYN-ACK packets are generated by the syncache. See
1519 * tcp_syncache.c for details.
1521 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
1522 * depends on this property. In addition, these ISNs should be
1523 * unguessable so as to prevent connection hijacking. To satisfy
1524 * the requirements of this situation, the algorithm outlined in
1525 * RFC 1948 is used, with only small modifications.
1527 * Implementation details:
1529 * Time is based off the system timer, and is corrected so that it
1530 * increases by one megabyte per second. This allows for proper
1531 * recycling on high speed LANs while still leaving over an hour
1534 * As reading the *exact* system time is too expensive to be done
1535 * whenever setting up a TCP connection, we increment the time
1536 * offset in two ways. First, a small random positive increment
1537 * is added to isn_offset for each connection that is set up.
1538 * Second, the function tcp_isn_tick fires once per clock tick
1539 * and increments isn_offset as necessary so that sequence numbers
1540 * are incremented at approximately ISN_BYTES_PER_SECOND. The
1541 * random positive increments serve only to ensure that the same
1542 * exact sequence number is never sent out twice (as could otherwise
1543 * happen when a port is recycled in less than the system tick
1546 * net.inet.tcp.isn_reseed_interval controls the number of seconds
1547 * between seeding of isn_secret. This is normally set to zero,
1548 * as reseeding should not be necessary.
1550 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
1551 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In
1552 * general, this means holding an exclusive (write) lock.
1555 #define ISN_BYTES_PER_SECOND 1048576
1556 #define ISN_STATIC_INCREMENT 4096
1557 #define ISN_RANDOM_INCREMENT (4096 - 1)
1559 static VNET_DEFINE(u_char, isn_secret[32]);
1560 static VNET_DEFINE(int, isn_last);
1561 static VNET_DEFINE(int, isn_last_reseed);
1562 static VNET_DEFINE(u_int32_t, isn_offset);
1563 static VNET_DEFINE(u_int32_t, isn_offset_old);
1565 #define V_isn_secret VNET(isn_secret)
1566 #define V_isn_last VNET(isn_last)
1567 #define V_isn_last_reseed VNET(isn_last_reseed)
1568 #define V_isn_offset VNET(isn_offset)
1569 #define V_isn_offset_old VNET(isn_offset_old)
1572 tcp_new_isn(struct tcpcb *tp)
1575 u_int32_t md5_buffer[4];
1577 u_int32_t projected_offset;
1579 INP_WLOCK_ASSERT(tp->t_inpcb);
1582 /* Seed if this is the first use, reseed if requested. */
1583 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) &&
1584 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz)
1586 read_random(&V_isn_secret, sizeof(V_isn_secret));
1587 V_isn_last_reseed = ticks;
1590 /* Compute the md5 hash and return the ISN. */
1592 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
1593 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
1595 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
1596 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
1597 sizeof(struct in6_addr));
1598 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
1599 sizeof(struct in6_addr));
1603 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
1604 sizeof(struct in_addr));
1605 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
1606 sizeof(struct in_addr));
1608 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret));
1609 MD5Final((u_char *) &md5_buffer, &isn_ctx);
1610 new_isn = (tcp_seq) md5_buffer[0];
1611 V_isn_offset += ISN_STATIC_INCREMENT +
1612 (arc4random() & ISN_RANDOM_INCREMENT);
1613 if (ticks != V_isn_last) {
1614 projected_offset = V_isn_offset_old +
1615 ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last);
1616 if (SEQ_GT(projected_offset, V_isn_offset))
1617 V_isn_offset = projected_offset;
1618 V_isn_offset_old = V_isn_offset;
1621 new_isn += V_isn_offset;
1627 * When a specific ICMP unreachable message is received and the
1628 * connection state is SYN-SENT, drop the connection. This behavior
1629 * is controlled by the icmp_may_rst sysctl.
1632 tcp_drop_syn_sent(struct inpcb *inp, int errno)
1636 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
1637 INP_WLOCK_ASSERT(inp);
1639 if ((inp->inp_flags & INP_TIMEWAIT) ||
1640 (inp->inp_flags & INP_DROPPED))
1643 tp = intotcpcb(inp);
1644 if (tp->t_state != TCPS_SYN_SENT)
1647 tp = tcp_drop(tp, errno);
1655 * When `need fragmentation' ICMP is received, update our idea of the MSS
1656 * based on the new value in the route. Also nudge TCP to send something,
1657 * since we know the packet we just sent was dropped.
1658 * This duplicates some code in the tcp_mss() function in tcp_input.c.
1661 tcp_mtudisc(struct inpcb *inp, int errno)
1666 INP_WLOCK_ASSERT(inp);
1667 if ((inp->inp_flags & INP_TIMEWAIT) ||
1668 (inp->inp_flags & INP_DROPPED))
1671 tp = intotcpcb(inp);
1672 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
1674 tcp_mss_update(tp, -1, NULL, NULL);
1676 so = inp->inp_socket;
1677 SOCKBUF_LOCK(&so->so_snd);
1678 /* If the mss is larger than the socket buffer, decrease the mss. */
1679 if (so->so_snd.sb_hiwat < tp->t_maxseg)
1680 tp->t_maxseg = so->so_snd.sb_hiwat;
1681 SOCKBUF_UNLOCK(&so->so_snd);
1683 TCPSTAT_INC(tcps_mturesent);
1685 tp->snd_nxt = tp->snd_una;
1686 tcp_free_sackholes(tp);
1687 tp->snd_recover = tp->snd_max;
1688 if (tp->t_flags & TF_SACK_PERMIT)
1689 EXIT_FASTRECOVERY(tp->t_flags);
1690 tcp_output_send(tp);
1696 * Look-up the routing entry to the peer of this inpcb. If no route
1697 * is found and it cannot be allocated, then return 0. This routine
1698 * is called by TCP routines that access the rmx structure and by
1699 * tcp_mss_update to get the peer/interface MTU.
1702 tcp_maxmtu(struct in_conninfo *inc, int *flags)
1705 struct sockaddr_in *dst;
1709 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
1711 bzero(&sro, sizeof(sro));
1712 if (inc->inc_faddr.s_addr != INADDR_ANY) {
1713 dst = (struct sockaddr_in *)&sro.ro_dst;
1714 dst->sin_family = AF_INET;
1715 dst->sin_len = sizeof(*dst);
1716 dst->sin_addr = inc->inc_faddr;
1717 in_rtalloc_ign(&sro, 0, inc->inc_fibnum);
1719 if (sro.ro_rt != NULL) {
1720 ifp = sro.ro_rt->rt_ifp;
1721 if (sro.ro_rt->rt_rmx.rmx_mtu == 0)
1722 maxmtu = ifp->if_mtu;
1724 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu);
1726 /* Report additional interface capabilities. */
1727 if (flags != NULL) {
1728 if (ifp->if_capenable & IFCAP_TSO4 &&
1729 ifp->if_hwassist & CSUM_TSO)
1740 tcp_maxmtu6(struct in_conninfo *inc, int *flags)
1742 struct route_in6 sro6;
1746 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
1748 bzero(&sro6, sizeof(sro6));
1749 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
1750 sro6.ro_dst.sin6_family = AF_INET6;
1751 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
1752 sro6.ro_dst.sin6_addr = inc->inc6_faddr;
1753 in6_rtalloc_ign(&sro6, 0, inc->inc_fibnum);
1755 if (sro6.ro_rt != NULL) {
1756 ifp = sro6.ro_rt->rt_ifp;
1757 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0)
1758 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp);
1760 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu,
1761 IN6_LINKMTU(sro6.ro_rt->rt_ifp));
1763 /* Report additional interface capabilities. */
1764 if (flags != NULL) {
1765 if (ifp->if_capenable & IFCAP_TSO6 &&
1766 ifp->if_hwassist & CSUM_TSO)
1777 /* compute ESP/AH header size for TCP, including outer IP header. */
1779 ipsec_hdrsiz_tcp(struct tcpcb *tp)
1786 struct ip6_hdr *ip6;
1790 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
1792 MGETHDR(m, M_DONTWAIT, MT_DATA);
1797 if ((inp->inp_vflag & INP_IPV6) != 0) {
1798 ip6 = mtod(m, struct ip6_hdr *);
1799 th = (struct tcphdr *)(ip6 + 1);
1800 m->m_pkthdr.len = m->m_len =
1801 sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1802 tcpip_fillheaders(inp, ip6, th);
1803 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1807 ip = mtod(m, struct ip *);
1808 th = (struct tcphdr *)(ip + 1);
1809 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
1810 tcpip_fillheaders(inp, ip, th);
1811 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1819 #ifdef TCP_SIGNATURE
1821 * Callback function invoked by m_apply() to digest TCP segment data
1822 * contained within an mbuf chain.
1825 tcp_signature_apply(void *fstate, void *data, u_int len)
1828 MD5Update(fstate, (u_char *)data, len);
1833 * Compute TCP-MD5 hash of a TCP segment. (RFC2385)
1836 * m pointer to head of mbuf chain
1838 * len length of TCP segment data, excluding options
1839 * optlen length of TCP segment options
1840 * buf pointer to storage for computed MD5 digest
1841 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND)
1843 * We do this over ip, tcphdr, segment data, and the key in the SADB.
1844 * When called from tcp_input(), we can be sure that th_sum has been
1845 * zeroed out and verified already.
1847 * Return 0 if successful, otherwise return -1.
1849 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a
1850 * search with the destination IP address, and a 'magic SPI' to be
1851 * determined by the application. This is hardcoded elsewhere to 1179
1852 * right now. Another branch of this code exists which uses the SPD to
1853 * specify per-application flows but it is unstable.
1856 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen,
1857 u_char *buf, u_int direction)
1859 union sockaddr_union dst;
1861 struct ippseudo ippseudo;
1867 struct ipovly *ipovly;
1869 struct secasvar *sav;
1872 struct ip6_hdr *ip6;
1873 struct in6_addr in6;
1874 char ip6buf[INET6_ADDRSTRLEN];
1880 KASSERT(m != NULL, ("NULL mbuf chain"));
1881 KASSERT(buf != NULL, ("NULL signature pointer"));
1883 /* Extract the destination from the IP header in the mbuf. */
1884 bzero(&dst, sizeof(union sockaddr_union));
1885 ip = mtod(m, struct ip *);
1887 ip6 = NULL; /* Make the compiler happy. */
1892 dst.sa.sa_len = sizeof(struct sockaddr_in);
1893 dst.sa.sa_family = AF_INET;
1894 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ?
1895 ip->ip_src : ip->ip_dst;
1899 case (IPV6_VERSION >> 4):
1900 ip6 = mtod(m, struct ip6_hdr *);
1901 dst.sa.sa_len = sizeof(struct sockaddr_in6);
1902 dst.sa.sa_family = AF_INET6;
1903 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ?
1904 ip6->ip6_src : ip6->ip6_dst;
1913 /* Look up an SADB entry which matches the address of the peer. */
1914 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI));
1916 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__,
1917 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) :
1919 (ip->ip_v == (IPV6_VERSION >> 4)) ?
1920 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) :
1928 * Step 1: Update MD5 hash with IP(v6) pseudo-header.
1930 * XXX The ippseudo header MUST be digested in network byte order,
1931 * or else we'll fail the regression test. Assume all fields we've
1932 * been doing arithmetic on have been in host byte order.
1933 * XXX One cannot depend on ipovly->ih_len here. When called from
1934 * tcp_output(), the underlying ip_len member has not yet been set.
1939 ipovly = (struct ipovly *)ip;
1940 ippseudo.ippseudo_src = ipovly->ih_src;
1941 ippseudo.ippseudo_dst = ipovly->ih_dst;
1942 ippseudo.ippseudo_pad = 0;
1943 ippseudo.ippseudo_p = IPPROTO_TCP;
1944 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) +
1946 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo));
1948 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip));
1949 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen;
1954 * RFC 2385, 2.0 Proposal
1955 * For IPv6, the pseudo-header is as described in RFC 2460, namely the
1956 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero-
1957 * extended next header value (to form 32 bits), and 32-bit segment
1959 * Note: Upper-Layer Packet Length comes before Next Header.
1961 case (IPV6_VERSION >> 4):
1963 in6_clearscope(&in6);
1964 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
1966 in6_clearscope(&in6);
1967 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
1968 plen = htonl(len + sizeof(struct tcphdr) + optlen);
1969 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t));
1971 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
1972 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
1973 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
1975 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
1977 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr));
1978 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen;
1989 * Step 2: Update MD5 hash with TCP header, excluding options.
1990 * The TCP checksum must be set to zero.
1992 savecsum = th->th_sum;
1994 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr));
1995 th->th_sum = savecsum;
1998 * Step 3: Update MD5 hash with TCP segment data.
1999 * Use m_apply() to avoid an early m_pullup().
2002 m_apply(m, doff, len, tcp_signature_apply, &ctx);
2005 * Step 4: Update MD5 hash with shared secret.
2007 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth));
2008 MD5Final(buf, &ctx);
2010 key_sa_recordxfer(sav, m);
2016 * Verify the TCP-MD5 hash of a TCP segment. (RFC2385)
2019 * m pointer to head of mbuf chain
2020 * len length of TCP segment data, excluding options
2021 * optlen length of TCP segment options
2022 * buf pointer to storage for computed MD5 digest
2023 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND)
2025 * Return 1 if successful, otherwise return 0.
2028 tcp_signature_verify(struct mbuf *m, int off0, int tlen, int optlen,
2029 struct tcpopt *to, struct tcphdr *th, u_int tcpbflag)
2031 char tmpdigest[TCP_SIGLEN];
2033 if (tcp_sig_checksigs == 0)
2035 if ((tcpbflag & TF_SIGNATURE) == 0) {
2036 if ((to->to_flags & TOF_SIGNATURE) != 0) {
2039 * If this socket is not expecting signature but
2040 * the segment contains signature just fail.
2042 TCPSTAT_INC(tcps_sig_err_sigopt);
2043 TCPSTAT_INC(tcps_sig_rcvbadsig);
2047 /* Signature is not expected, and not present in segment. */
2052 * If this socket is expecting signature but the segment does not
2053 * contain any just fail.
2055 if ((to->to_flags & TOF_SIGNATURE) == 0) {
2056 TCPSTAT_INC(tcps_sig_err_nosigopt);
2057 TCPSTAT_INC(tcps_sig_rcvbadsig);
2060 if (tcp_signature_compute(m, off0, tlen, optlen, &tmpdigest[0],
2061 IPSEC_DIR_INBOUND) == -1) {
2062 TCPSTAT_INC(tcps_sig_err_buildsig);
2063 TCPSTAT_INC(tcps_sig_rcvbadsig);
2067 if (bcmp(to->to_signature, &tmpdigest[0], TCP_SIGLEN) != 0) {
2068 TCPSTAT_INC(tcps_sig_rcvbadsig);
2071 TCPSTAT_INC(tcps_sig_rcvgoodsig);
2074 #endif /* TCP_SIGNATURE */
2077 sysctl_drop(SYSCTL_HANDLER_ARGS)
2079 /* addrs[0] is a foreign socket, addrs[1] is a local one. */
2080 struct sockaddr_storage addrs[2];
2084 struct sockaddr_in *fin, *lin;
2086 struct sockaddr_in6 *fin6, *lin6;
2097 if (req->oldptr != NULL || req->oldlen != 0)
2099 if (req->newptr == NULL)
2101 if (req->newlen < sizeof(addrs))
2103 error = SYSCTL_IN(req, &addrs, sizeof(addrs));
2107 switch (addrs[0].ss_family) {
2110 fin6 = (struct sockaddr_in6 *)&addrs[0];
2111 lin6 = (struct sockaddr_in6 *)&addrs[1];
2112 if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
2113 lin6->sin6_len != sizeof(struct sockaddr_in6))
2115 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
2116 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
2118 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
2119 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
2120 fin = (struct sockaddr_in *)&addrs[0];
2121 lin = (struct sockaddr_in *)&addrs[1];
2124 error = sa6_embedscope(fin6, V_ip6_use_defzone);
2127 error = sa6_embedscope(lin6, V_ip6_use_defzone);
2134 fin = (struct sockaddr_in *)&addrs[0];
2135 lin = (struct sockaddr_in *)&addrs[1];
2136 if (fin->sin_len != sizeof(struct sockaddr_in) ||
2137 lin->sin_len != sizeof(struct sockaddr_in))
2144 INP_INFO_WLOCK(&V_tcbinfo);
2145 switch (addrs[0].ss_family) {
2148 inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
2149 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
2150 INPLOOKUP_WLOCKPCB, NULL);
2155 inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
2156 lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
2161 if (inp->inp_flags & INP_TIMEWAIT) {
2163 * XXXRW: There currently exists a state where an
2164 * inpcb is present, but its timewait state has been
2165 * discarded. For now, don't allow dropping of this
2173 } else if (!(inp->inp_flags & INP_DROPPED) &&
2174 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) {
2175 tp = intotcpcb(inp);
2176 tp = tcp_drop(tp, ECONNABORTED);
2183 INP_INFO_WUNLOCK(&V_tcbinfo);
2187 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
2188 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL,
2189 0, sysctl_drop, "", "Drop TCP connection");
2192 * Generate a standardized TCP log line for use throughout the
2193 * tcp subsystem. Memory allocation is done with M_NOWAIT to
2194 * allow use in the interrupt context.
2196 * NB: The caller MUST free(s, M_TCPLOG) the returned string.
2197 * NB: The function may return NULL if memory allocation failed.
2199 * Due to header inclusion and ordering limitations the struct ip
2200 * and ip6_hdr pointers have to be passed as void pointers.
2203 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2207 /* Is logging enabled? */
2208 if (tcp_log_in_vain == 0)
2211 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
2215 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2219 /* Is logging enabled? */
2220 if (tcp_log_debug == 0)
2223 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
2227 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2234 const struct ip6_hdr *ip6;
2236 ip6 = (const struct ip6_hdr *)ip6hdr;
2238 ip = (struct ip *)ip4hdr;
2241 * The log line looks like this:
2242 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>"
2244 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") +
2245 sizeof(PRINT_TH_FLAGS) + 1 +
2247 2 * INET6_ADDRSTRLEN;
2249 2 * INET_ADDRSTRLEN;
2252 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT);
2256 strcat(s, "TCP: [");
2259 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) {
2260 inet_ntoa_r(inc->inc_faddr, sp);
2262 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2264 inet_ntoa_r(inc->inc_laddr, sp);
2266 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2269 ip6_sprintf(sp, &inc->inc6_faddr);
2271 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2273 ip6_sprintf(sp, &inc->inc6_laddr);
2275 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2276 } else if (ip6 && th) {
2277 ip6_sprintf(sp, &ip6->ip6_src);
2279 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2281 ip6_sprintf(sp, &ip6->ip6_dst);
2283 sprintf(sp, "]:%i", ntohs(th->th_dport));
2286 } else if (ip && th) {
2287 inet_ntoa_r(ip->ip_src, sp);
2289 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2291 inet_ntoa_r(ip->ip_dst, sp);
2293 sprintf(sp, "]:%i", ntohs(th->th_dport));
2301 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS);
2302 if (*(s + size - 1) != '\0')
2303 panic("%s: string too long", __func__);