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/kernel.h>
45 #include <sys/sysctl.h>
47 #include <sys/malloc.h>
50 #include <sys/domain.h>
54 #include <sys/socket.h>
55 #include <sys/socketvar.h>
56 #include <sys/protosw.h>
57 #include <sys/random.h>
61 #include <net/route.h>
65 #include <netinet/in.h>
66 #include <netinet/in_systm.h>
67 #include <netinet/ip.h>
69 #include <netinet/ip6.h>
71 #include <netinet/in_pcb.h>
73 #include <netinet6/in6_pcb.h>
75 #include <netinet/in_var.h>
76 #include <netinet/ip_var.h>
78 #include <netinet6/ip6_var.h>
79 #include <netinet6/scope6_var.h>
80 #include <netinet6/nd6.h>
82 #include <netinet/ip_icmp.h>
83 #include <netinet/tcp.h>
84 #include <netinet/tcp_fsm.h>
85 #include <netinet/tcp_seq.h>
86 #include <netinet/tcp_timer.h>
87 #include <netinet/tcp_var.h>
88 #include <netinet/tcp_syncache.h>
89 #include <netinet/tcp_offload.h>
91 #include <netinet6/tcp6_var.h>
93 #include <netinet/tcpip.h>
95 #include <netinet/tcp_debug.h>
97 #include <netinet6/ip6protosw.h>
100 #include <netipsec/ipsec.h>
101 #include <netipsec/xform.h>
103 #include <netipsec/ipsec6.h>
105 #include <netipsec/key.h>
106 #include <sys/syslog.h>
109 #include <machine/in_cksum.h>
112 #include <security/mac/mac_framework.h>
114 VNET_DEFINE(int, tcp_mssdflt);
116 VNET_DEFINE(int, tcp_v6mssdflt);
118 VNET_DEFINE(int, tcp_minmss);
119 VNET_DEFINE(int, tcp_do_rfc1323);
121 static VNET_DEFINE(int, icmp_may_rst);
122 static VNET_DEFINE(int, tcp_isn_reseed_interval);
123 static VNET_DEFINE(int, tcp_inflight_enable);
124 static VNET_DEFINE(int, tcp_inflight_rttthresh);
125 static VNET_DEFINE(int, tcp_inflight_min);
126 static VNET_DEFINE(int, tcp_inflight_max);
127 static VNET_DEFINE(int, tcp_inflight_stab);
129 #define V_icmp_may_rst VNET(icmp_may_rst)
130 #define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval)
131 #define V_tcp_inflight_enable VNET(tcp_inflight_enable)
132 #define V_tcp_inflight_rttthresh VNET(tcp_inflight_rttthresh)
133 #define V_tcp_inflight_min VNET(tcp_inflight_min)
134 #define V_tcp_inflight_max VNET(tcp_inflight_max)
135 #define V_tcp_inflight_stab VNET(tcp_inflight_stab)
138 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
143 error = sysctl_handle_int(oidp, &new, 0, req);
144 if (error == 0 && req->newptr) {
145 if (new < TCP_MINMSS)
153 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
154 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_mssdflt), 0,
155 &sysctl_net_inet_tcp_mss_check, "I",
156 "Default TCP Maximum Segment Size");
160 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS)
164 new = V_tcp_v6mssdflt;
165 error = sysctl_handle_int(oidp, &new, 0, req);
166 if (error == 0 && req->newptr) {
167 if (new < TCP_MINMSS)
170 V_tcp_v6mssdflt = new;
175 SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
176 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_v6mssdflt), 0,
177 &sysctl_net_inet_tcp_mss_v6_check, "I",
178 "Default TCP Maximum Segment Size for IPv6");
182 vnet_sysctl_msec_to_ticks(SYSCTL_HANDLER_ARGS)
185 VNET_SYSCTL_ARG(req, arg1);
186 return (sysctl_msec_to_ticks(oidp, arg1, arg2, req));
190 * Minimum MSS we accept and use. This prevents DoS attacks where
191 * we are forced to a ridiculous low MSS like 20 and send hundreds
192 * of packets instead of one. The effect scales with the available
193 * bandwidth and quickly saturates the CPU and network interface
194 * with packet generation and sending. Set to zero to disable MINMSS
195 * checking. This setting prevents us from sending too small packets.
197 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW,
198 &VNET_NAME(tcp_minmss), 0,
199 "Minmum TCP Maximum Segment Size");
201 SYSCTL_VNET_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
202 &VNET_NAME(tcp_do_rfc1323), 0,
203 "Enable rfc1323 (high performance TCP) extensions");
205 static int tcp_log_debug = 0;
206 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW,
207 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments");
209 static int tcp_tcbhashsize = 0;
210 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN,
211 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
213 static int do_tcpdrain = 1;
214 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
215 "Enable tcp_drain routine for extra help when low on mbufs");
217 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
218 &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
220 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW,
221 &VNET_NAME(icmp_may_rst), 0,
222 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
224 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
225 &VNET_NAME(tcp_isn_reseed_interval), 0,
226 "Seconds between reseeding of ISN secret");
229 * TCP bandwidth limiting sysctls. Note that the default lower bound of
230 * 1024 exists only for debugging. A good production default would be
231 * something like 6100.
233 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0,
234 "TCP inflight data limiting");
236 SYSCTL_VNET_INT(_net_inet_tcp_inflight, OID_AUTO, enable, CTLFLAG_RW,
237 &VNET_NAME(tcp_inflight_enable), 0,
238 "Enable automatic TCP inflight data limiting");
240 static int tcp_inflight_debug = 0;
241 SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW,
242 &tcp_inflight_debug, 0,
243 "Debug TCP inflight calculations");
245 SYSCTL_VNET_PROC(_net_inet_tcp_inflight, OID_AUTO, rttthresh,
246 CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(tcp_inflight_rttthresh), 0,
247 vnet_sysctl_msec_to_ticks, "I",
248 "RTT threshold below which inflight will deactivate itself");
250 SYSCTL_VNET_INT(_net_inet_tcp_inflight, OID_AUTO, min, CTLFLAG_RW,
251 &VNET_NAME(tcp_inflight_min), 0,
252 "Lower-bound for TCP inflight window");
254 SYSCTL_VNET_INT(_net_inet_tcp_inflight, OID_AUTO, max, CTLFLAG_RW,
255 &VNET_NAME(tcp_inflight_max), 0,
256 "Upper-bound for TCP inflight window");
258 SYSCTL_VNET_INT(_net_inet_tcp_inflight, OID_AUTO, stab, CTLFLAG_RW,
259 &VNET_NAME(tcp_inflight_stab), 0,
260 "Inflight Algorithm Stabilization 20 = 2 packets");
262 VNET_DEFINE(uma_zone_t, sack_hole_zone);
263 #define V_sack_hole_zone VNET(sack_hole_zone)
265 static struct inpcb *tcp_notify(struct inpcb *, int);
266 static void tcp_isn_tick(void *);
269 * Target size of TCP PCB hash tables. Must be a power of two.
271 * Note that this can be overridden by the kernel environment
272 * variable net.inet.tcp.tcbhashsize
275 #define TCBHASHSIZE 512
280 * Callouts should be moved into struct tcp directly. They are currently
281 * separate because the tcpcb structure is exported to userland for sysctl
282 * parsing purposes, which do not know about callouts.
289 static VNET_DEFINE(uma_zone_t, tcpcb_zone);
290 #define V_tcpcb_zone VNET(tcpcb_zone)
292 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
293 struct callout isn_callout;
294 static struct mtx isn_mtx;
296 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF)
297 #define ISN_LOCK() mtx_lock(&isn_mtx)
298 #define ISN_UNLOCK() mtx_unlock(&isn_mtx)
301 * TCP initialization.
304 tcp_zone_change(void *tag)
307 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets);
308 uma_zone_set_max(V_tcpcb_zone, maxsockets);
309 tcp_tw_zone_change();
313 tcp_inpcb_init(void *mem, int size, int flags)
315 struct inpcb *inp = mem;
317 INP_LOCK_INIT(inp, "inp", "tcpinp");
327 V_tcp_delack_enabled = 1;
329 V_tcp_do_rfc3042 = 1;
330 V_tcp_do_rfc3390 = 1;
332 V_tcp_ecn_maxretries = 1;
333 V_tcp_insecure_rst = 0;
334 V_tcp_do_autorcvbuf = 1;
335 V_tcp_autorcvbuf_inc = 16*1024;
336 V_tcp_autorcvbuf_max = 256*1024;
337 V_tcp_do_rfc3465 = 1;
340 V_tcp_mssdflt = TCP_MSS;
342 V_tcp_v6mssdflt = TCP6_MSS;
344 V_tcp_minmss = TCP_MINMSS;
345 V_tcp_do_rfc1323 = 1;
347 V_tcp_isn_reseed_interval = 0;
348 V_tcp_inflight_enable = 1;
349 V_tcp_inflight_min = 6144;
350 V_tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT;
351 V_tcp_inflight_stab = 20;
353 V_path_mtu_discovery = 1;
355 V_ss_fltsz_local = 4;
356 V_tcp_do_newreno = 1;
358 V_tcp_do_autosndbuf = 1;
359 V_tcp_autosndbuf_inc = 8*1024;
360 V_tcp_autosndbuf_max = 256*1024;
362 V_nolocaltimewait = 0;
365 V_tcp_sack_maxholes = 128;
366 V_tcp_sack_globalmaxholes = 65536;
367 V_tcp_sack_globalholes = 0;
369 V_tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH;
371 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
373 INP_INFO_LOCK_INIT(&V_tcbinfo, "tcp");
376 V_tcbinfo.ipi_vnet = curvnet;
378 V_tcbinfo.ipi_listhead = &V_tcb;
379 hashsize = TCBHASHSIZE;
380 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
381 if (!powerof2(hashsize)) {
382 printf("WARNING: TCB hash size not a power of 2\n");
383 hashsize = 512; /* safe default */
385 V_tcbinfo.ipi_hashbase = hashinit(hashsize, M_PCB,
386 &V_tcbinfo.ipi_hashmask);
387 V_tcbinfo.ipi_porthashbase = hashinit(hashsize, M_PCB,
388 &V_tcbinfo.ipi_porthashmask);
389 V_tcbinfo.ipi_zone = uma_zcreate("tcp_inpcb", sizeof(struct inpcb),
390 NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
391 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets);
393 * These have to be type stable for the benefit of the timers.
395 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
396 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
397 uma_zone_set_max(V_tcpcb_zone, maxsockets);
402 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
403 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
405 /* Skip initialization of globals for non-default instances. */
406 if (!IS_DEFAULT_VNET(curvnet))
409 /* XXX virtualize those bellow? */
410 tcp_delacktime = TCPTV_DELACK;
411 tcp_keepinit = TCPTV_KEEP_INIT;
412 tcp_keepidle = TCPTV_KEEP_IDLE;
413 tcp_keepintvl = TCPTV_KEEPINTVL;
414 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
416 tcp_rexmit_min = TCPTV_MIN;
417 if (tcp_rexmit_min < 1)
419 tcp_rexmit_slop = TCPTV_CPU_VAR;
420 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
421 tcp_tcbhashsize = hashsize;
424 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
426 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
428 if (max_protohdr < TCP_MINPROTOHDR)
429 max_protohdr = TCP_MINPROTOHDR;
430 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
432 #undef TCP_MINPROTOHDR
435 callout_init(&isn_callout, CALLOUT_MPSAFE);
436 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL);
437 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
438 SHUTDOWN_PRI_DEFAULT);
439 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL,
440 EVENTHANDLER_PRI_ANY);
452 /* XXX check that hashes are empty! */
453 hashdestroy(V_tcbinfo.ipi_hashbase, M_PCB,
454 V_tcbinfo.ipi_hashmask);
455 hashdestroy(V_tcbinfo.ipi_porthashbase, M_PCB,
456 V_tcbinfo.ipi_porthashmask);
457 INP_INFO_LOCK_DESTROY(&V_tcbinfo);
465 callout_stop(&isn_callout);
469 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
470 * tcp_template used to store this data in mbufs, but we now recopy it out
471 * of the tcpcb each time to conserve mbufs.
474 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr)
476 struct tcphdr *th = (struct tcphdr *)tcp_ptr;
478 INP_WLOCK_ASSERT(inp);
481 if ((inp->inp_vflag & INP_IPV6) != 0) {
484 ip6 = (struct ip6_hdr *)ip_ptr;
485 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
486 (inp->inp_flow & IPV6_FLOWINFO_MASK);
487 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
488 (IPV6_VERSION & IPV6_VERSION_MASK);
489 ip6->ip6_nxt = IPPROTO_TCP;
490 ip6->ip6_plen = htons(sizeof(struct tcphdr));
491 ip6->ip6_src = inp->in6p_laddr;
492 ip6->ip6_dst = inp->in6p_faddr;
498 ip = (struct ip *)ip_ptr;
499 ip->ip_v = IPVERSION;
501 ip->ip_tos = inp->inp_ip_tos;
505 ip->ip_ttl = inp->inp_ip_ttl;
507 ip->ip_p = IPPROTO_TCP;
508 ip->ip_src = inp->inp_laddr;
509 ip->ip_dst = inp->inp_faddr;
511 th->th_sport = inp->inp_lport;
512 th->th_dport = inp->inp_fport;
520 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */
524 * Create template to be used to send tcp packets on a connection.
525 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
526 * use for this function is in keepalives, which use tcp_respond.
529 tcpip_maketemplate(struct inpcb *inp)
533 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT);
536 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t);
541 * Send a single message to the TCP at address specified by
542 * the given TCP/IP header. If m == NULL, then we make a copy
543 * of the tcpiphdr at ti and send directly to the addressed host.
544 * This is used to force keep alive messages out using the TCP
545 * template for a connection. If flags are given then we send
546 * a message back to the TCP which originated the * segment ti,
547 * and discard the mbuf containing it and any other attached mbufs.
549 * In any case the ack and sequence number of the transmitted
550 * segment are as specified by the parameters.
552 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
555 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
556 tcp_seq ack, tcp_seq seq, int flags)
569 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
572 isipv6 = ((struct ip *)ipgen)->ip_v == 6;
579 KASSERT(inp != NULL, ("tcp control block w/o inpcb"));
580 INP_WLOCK_ASSERT(inp);
585 if (!(flags & TH_RST)) {
586 win = sbspace(&inp->inp_socket->so_rcv);
587 if (win > (long)TCP_MAXWIN << tp->rcv_scale)
588 win = (long)TCP_MAXWIN << tp->rcv_scale;
592 m = m_gethdr(M_DONTWAIT, MT_DATA);
596 m->m_data += max_linkhdr;
599 bcopy((caddr_t)ip6, mtod(m, caddr_t),
600 sizeof(struct ip6_hdr));
601 ip6 = mtod(m, struct ip6_hdr *);
602 nth = (struct tcphdr *)(ip6 + 1);
606 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
607 ip = mtod(m, struct ip *);
608 nth = (struct tcphdr *)(ip + 1);
610 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
615 * XXX MRT We inherrit the FIB, which is lucky.
619 m->m_data = (caddr_t)ipgen;
620 /* m_len is set later */
622 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
625 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
626 nth = (struct tcphdr *)(ip6 + 1);
630 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
631 nth = (struct tcphdr *)(ip + 1);
635 * this is usually a case when an extension header
636 * exists between the IPv6 header and the
639 nth->th_sport = th->th_sport;
640 nth->th_dport = th->th_dport;
642 xchg(nth->th_dport, nth->th_sport, uint16_t);
648 ip6->ip6_vfc = IPV6_VERSION;
649 ip6->ip6_nxt = IPPROTO_TCP;
650 ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) +
652 tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
656 tlen += sizeof (struct tcpiphdr);
658 ip->ip_ttl = V_ip_defttl;
659 if (V_path_mtu_discovery)
663 m->m_pkthdr.len = tlen;
664 m->m_pkthdr.rcvif = NULL;
668 * Packet is associated with a socket, so allow the
669 * label of the response to reflect the socket label.
671 INP_WLOCK_ASSERT(inp);
672 mac_inpcb_create_mbuf(inp, m);
675 * Packet is not associated with a socket, so possibly
676 * update the label in place.
678 mac_netinet_tcp_reply(m);
681 nth->th_seq = htonl(seq);
682 nth->th_ack = htonl(ack);
684 nth->th_off = sizeof (struct tcphdr) >> 2;
685 nth->th_flags = flags;
687 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
689 nth->th_win = htons((u_short)win);
694 nth->th_sum = in6_cksum(m, IPPROTO_TCP,
695 sizeof(struct ip6_hdr),
696 tlen - sizeof(struct ip6_hdr));
697 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb :
702 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
703 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
704 m->m_pkthdr.csum_flags = CSUM_TCP;
705 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
708 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
709 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
713 (void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp);
716 (void) ip_output(m, NULL, NULL, ipflags, NULL, inp);
720 * Create a new TCP control block, making an
721 * empty reassembly queue and hooking it to the argument
722 * protocol control block. The `inp' parameter must have
723 * come from the zone allocator set up in tcp_init().
726 tcp_newtcpcb(struct inpcb *inp)
728 struct tcpcb_mem *tm;
731 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
734 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO);
739 tp->t_vnet = inp->inp_vnet;
741 tp->t_timers = &tm->tt;
742 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */
743 tp->t_maxseg = tp->t_maxopd =
745 isipv6 ? V_tcp_v6mssdflt :
749 /* Set up our timeouts. */
750 callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE);
751 callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE);
752 callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE);
753 callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE);
754 callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE);
756 if (V_tcp_do_rfc1323)
757 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
759 tp->t_flags |= TF_SACK_PERMIT;
760 TAILQ_INIT(&tp->snd_holes);
761 tp->t_inpcb = inp; /* XXX */
763 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
764 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
765 * reasonable initial retransmit time.
767 tp->t_srtt = TCPTV_SRTTBASE;
768 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
769 tp->t_rttmin = tcp_rexmit_min;
770 tp->t_rxtcur = TCPTV_RTOBASE;
771 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
772 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
773 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
774 tp->t_rcvtime = ticks;
775 tp->t_bw_rtttime = ticks;
777 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
778 * because the socket may be bound to an IPv6 wildcard address,
779 * which may match an IPv4-mapped IPv6 address.
781 inp->inp_ip_ttl = V_ip_defttl;
783 return (tp); /* XXX */
787 * Drop a TCP connection, reporting
788 * the specified error. If connection is synchronized,
789 * then send a RST to peer.
792 tcp_drop(struct tcpcb *tp, int errno)
794 struct socket *so = tp->t_inpcb->inp_socket;
796 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
797 INP_WLOCK_ASSERT(tp->t_inpcb);
799 if (TCPS_HAVERCVDSYN(tp->t_state)) {
800 tp->t_state = TCPS_CLOSED;
801 (void) tcp_output_reset(tp);
802 TCPSTAT_INC(tcps_drops);
804 TCPSTAT_INC(tcps_conndrops);
805 if (errno == ETIMEDOUT && tp->t_softerror)
806 errno = tp->t_softerror;
807 so->so_error = errno;
808 return (tcp_close(tp));
812 tcp_discardcb(struct tcpcb *tp)
815 struct inpcb *inp = tp->t_inpcb;
816 struct socket *so = inp->inp_socket;
818 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
821 INP_WLOCK_ASSERT(inp);
824 * Make sure that all of our timers are stopped before we
827 callout_stop(&tp->t_timers->tt_rexmt);
828 callout_stop(&tp->t_timers->tt_persist);
829 callout_stop(&tp->t_timers->tt_keep);
830 callout_stop(&tp->t_timers->tt_2msl);
831 callout_stop(&tp->t_timers->tt_delack);
834 * If we got enough samples through the srtt filter,
835 * save the rtt and rttvar in the routing entry.
836 * 'Enough' is arbitrarily defined as 4 rtt samples.
837 * 4 samples is enough for the srtt filter to converge
838 * to within enough % of the correct value; fewer samples
839 * and we could save a bogus rtt. The danger is not high
840 * as tcp quickly recovers from everything.
841 * XXX: Works very well but needs some more statistics!
843 if (tp->t_rttupdated >= 4) {
844 struct hc_metrics_lite metrics;
847 bzero(&metrics, sizeof(metrics));
849 * Update the ssthresh always when the conditions below
850 * are satisfied. This gives us better new start value
851 * for the congestion avoidance for new connections.
852 * ssthresh is only set if packet loss occured on a session.
854 * XXXRW: 'so' may be NULL here, and/or socket buffer may be
855 * being torn down. Ideally this code would not use 'so'.
857 ssthresh = tp->snd_ssthresh;
858 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) {
860 * convert the limit from user data bytes to
861 * packets then to packet data bytes.
863 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg;
866 ssthresh *= (u_long)(tp->t_maxseg +
868 (isipv6 ? sizeof (struct ip6_hdr) +
869 sizeof (struct tcphdr) :
871 sizeof (struct tcpiphdr)
878 metrics.rmx_ssthresh = ssthresh;
880 metrics.rmx_rtt = tp->t_srtt;
881 metrics.rmx_rttvar = tp->t_rttvar;
882 /* XXX: This wraps if the pipe is more than 4 Gbit per second */
883 metrics.rmx_bandwidth = tp->snd_bandwidth;
884 metrics.rmx_cwnd = tp->snd_cwnd;
885 metrics.rmx_sendpipe = 0;
886 metrics.rmx_recvpipe = 0;
888 tcp_hc_update(&inp->inp_inc, &metrics);
891 /* free the reassembly queue, if any */
892 while ((q = LIST_FIRST(&tp->t_segq)) != NULL) {
893 LIST_REMOVE(q, tqe_q);
895 uma_zfree(V_tcp_reass_zone, q);
899 /* Disconnect offload device, if any. */
900 tcp_offload_detach(tp);
902 tcp_free_sackholes(tp);
903 inp->inp_ppcb = NULL;
905 uma_zfree(V_tcpcb_zone, tp);
909 * Attempt to close a TCP control block, marking it as dropped, and freeing
910 * the socket if we hold the only reference.
913 tcp_close(struct tcpcb *tp)
915 struct inpcb *inp = tp->t_inpcb;
918 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
919 INP_WLOCK_ASSERT(inp);
921 /* Notify any offload devices of listener close */
922 if (tp->t_state == TCPS_LISTEN)
923 tcp_offload_listen_close(tp);
925 TCPSTAT_INC(tcps_closed);
926 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
927 so = inp->inp_socket;
928 soisdisconnected(so);
929 if (inp->inp_flags & INP_SOCKREF) {
930 KASSERT(so->so_state & SS_PROTOREF,
931 ("tcp_close: !SS_PROTOREF"));
932 inp->inp_flags &= ~INP_SOCKREF;
936 so->so_state &= ~SS_PROTOREF;
946 VNET_ITERATOR_DECL(vnet_iter);
951 VNET_LIST_RLOCK_NOSLEEP();
952 VNET_FOREACH(vnet_iter) {
953 CURVNET_SET(vnet_iter);
956 struct tseg_qent *te;
959 * Walk the tcpbs, if existing, and flush the reassembly queue,
961 * XXX: The "Net/3" implementation doesn't imply that the TCP
962 * reassembly queue should be flushed, but in a situation
963 * where we're really low on mbufs, this is potentially
966 INP_INFO_RLOCK(&V_tcbinfo);
967 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) {
968 if (inpb->inp_flags & INP_TIMEWAIT)
971 if ((tcpb = intotcpcb(inpb)) != NULL) {
972 while ((te = LIST_FIRST(&tcpb->t_segq))
974 LIST_REMOVE(te, tqe_q);
976 uma_zfree(V_tcp_reass_zone, te);
980 tcp_clean_sackreport(tcpb);
984 INP_INFO_RUNLOCK(&V_tcbinfo);
987 VNET_LIST_RUNLOCK_NOSLEEP();
991 * Notify a tcp user of an asynchronous error;
992 * store error as soft error, but wake up user
993 * (for now, won't do anything until can select for soft error).
995 * Do not wake up user since there currently is no mechanism for
996 * reporting soft errors (yet - a kqueue filter may be added).
998 static struct inpcb *
999 tcp_notify(struct inpcb *inp, int error)
1003 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
1004 INP_WLOCK_ASSERT(inp);
1006 if ((inp->inp_flags & INP_TIMEWAIT) ||
1007 (inp->inp_flags & INP_DROPPED))
1010 tp = intotcpcb(inp);
1011 KASSERT(tp != NULL, ("tcp_notify: tp == NULL"));
1014 * Ignore some errors if we are hooked up.
1015 * If connection hasn't completed, has retransmitted several times,
1016 * and receives a second error, give up now. This is better
1017 * than waiting a long time to establish a connection that
1018 * can never complete.
1020 if (tp->t_state == TCPS_ESTABLISHED &&
1021 (error == EHOSTUNREACH || error == ENETUNREACH ||
1022 error == EHOSTDOWN)) {
1024 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
1026 tp = tcp_drop(tp, error);
1032 tp->t_softerror = error;
1036 wakeup( &so->so_timeo);
1043 tcp_pcblist(SYSCTL_HANDLER_ARGS)
1045 int error, i, m, n, pcb_count;
1046 struct inpcb *inp, **inp_list;
1051 * The process of preparing the TCB list is too time-consuming and
1052 * resource-intensive to repeat twice on every request.
1054 if (req->oldptr == NULL) {
1055 m = syncache_pcbcount();
1056 n = V_tcbinfo.ipi_count;
1057 req->oldidx = 2 * (sizeof xig)
1058 + ((m + n) + n/8) * sizeof(struct xtcpcb);
1062 if (req->newptr != NULL)
1066 * OK, now we're committed to doing something.
1068 INP_INFO_RLOCK(&V_tcbinfo);
1069 gencnt = V_tcbinfo.ipi_gencnt;
1070 n = V_tcbinfo.ipi_count;
1071 INP_INFO_RUNLOCK(&V_tcbinfo);
1073 m = syncache_pcbcount();
1075 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
1076 + (n + m) * sizeof(struct xtcpcb));
1080 xig.xig_len = sizeof xig;
1081 xig.xig_count = n + m;
1082 xig.xig_gen = gencnt;
1083 xig.xig_sogen = so_gencnt;
1084 error = SYSCTL_OUT(req, &xig, sizeof xig);
1088 error = syncache_pcblist(req, m, &pcb_count);
1092 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
1093 if (inp_list == NULL)
1096 INP_INFO_RLOCK(&V_tcbinfo);
1097 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0;
1098 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) {
1100 if (inp->inp_gencnt <= gencnt) {
1102 * XXX: This use of cr_cansee(), introduced with
1103 * TCP state changes, is not quite right, but for
1104 * now, better than nothing.
1106 if (inp->inp_flags & INP_TIMEWAIT) {
1107 if (intotw(inp) != NULL)
1108 error = cr_cansee(req->td->td_ucred,
1109 intotw(inp)->tw_cred);
1111 error = EINVAL; /* Skip this inp. */
1113 error = cr_canseeinpcb(req->td->td_ucred, inp);
1115 inp_list[i++] = inp;
1119 INP_INFO_RUNLOCK(&V_tcbinfo);
1123 for (i = 0; i < n; i++) {
1126 if (inp->inp_gencnt <= gencnt) {
1130 bzero(&xt, sizeof(xt));
1131 xt.xt_len = sizeof xt;
1132 /* XXX should avoid extra copy */
1133 bcopy(inp, &xt.xt_inp, sizeof *inp);
1134 inp_ppcb = inp->inp_ppcb;
1135 if (inp_ppcb == NULL)
1136 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
1137 else if (inp->inp_flags & INP_TIMEWAIT) {
1138 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
1139 xt.xt_tp.t_state = TCPS_TIME_WAIT;
1141 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
1142 if (inp->inp_socket != NULL)
1143 sotoxsocket(inp->inp_socket, &xt.xt_socket);
1145 bzero(&xt.xt_socket, sizeof xt.xt_socket);
1146 xt.xt_socket.xso_protocol = IPPROTO_TCP;
1148 xt.xt_inp.inp_gencnt = inp->inp_gencnt;
1150 error = SYSCTL_OUT(req, &xt, sizeof xt);
1157 * Give the user an updated idea of our state.
1158 * If the generation differs from what we told
1159 * her before, she knows that something happened
1160 * while we were processing this request, and it
1161 * might be necessary to retry.
1163 INP_INFO_RLOCK(&V_tcbinfo);
1164 xig.xig_gen = V_tcbinfo.ipi_gencnt;
1165 xig.xig_sogen = so_gencnt;
1166 xig.xig_count = V_tcbinfo.ipi_count + pcb_count;
1167 INP_INFO_RUNLOCK(&V_tcbinfo);
1168 error = SYSCTL_OUT(req, &xig, sizeof xig);
1170 free(inp_list, M_TEMP);
1174 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
1175 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
1178 tcp_getcred(SYSCTL_HANDLER_ARGS)
1181 struct sockaddr_in addrs[2];
1185 error = priv_check(req->td, PRIV_NETINET_GETCRED);
1188 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1191 INP_INFO_RLOCK(&V_tcbinfo);
1192 inp = in_pcblookup_hash(&V_tcbinfo, addrs[1].sin_addr,
1193 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
1196 INP_INFO_RUNLOCK(&V_tcbinfo);
1197 if (inp->inp_socket == NULL)
1200 error = cr_canseeinpcb(req->td->td_ucred, inp);
1202 cru2x(inp->inp_cred, &xuc);
1205 INP_INFO_RUNLOCK(&V_tcbinfo);
1209 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1213 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
1214 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1215 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection");
1219 tcp6_getcred(SYSCTL_HANDLER_ARGS)
1222 struct sockaddr_in6 addrs[2];
1224 int error, mapped = 0;
1226 error = priv_check(req->td, PRIV_NETINET_GETCRED);
1229 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1232 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
1233 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
1236 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
1237 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
1243 INP_INFO_RLOCK(&V_tcbinfo);
1245 inp = in_pcblookup_hash(&V_tcbinfo,
1246 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
1248 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
1252 inp = in6_pcblookup_hash(&V_tcbinfo,
1253 &addrs[1].sin6_addr, addrs[1].sin6_port,
1254 &addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL);
1257 INP_INFO_RUNLOCK(&V_tcbinfo);
1258 if (inp->inp_socket == NULL)
1261 error = cr_canseeinpcb(req->td->td_ucred, inp);
1263 cru2x(inp->inp_cred, &xuc);
1266 INP_INFO_RUNLOCK(&V_tcbinfo);
1270 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1274 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
1275 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1276 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection");
1281 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
1283 struct ip *ip = vip;
1285 struct in_addr faddr;
1288 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1290 struct in_conninfo inc;
1291 tcp_seq icmp_tcp_seq;
1294 faddr = ((struct sockaddr_in *)sa)->sin_addr;
1295 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
1298 if (cmd == PRC_MSGSIZE)
1299 notify = tcp_mtudisc;
1300 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
1301 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip)
1302 notify = tcp_drop_syn_sent;
1304 * Redirects don't need to be handled up here.
1306 else if (PRC_IS_REDIRECT(cmd))
1309 * Source quench is depreciated.
1311 else if (cmd == PRC_QUENCH)
1314 * Hostdead is ugly because it goes linearly through all PCBs.
1315 * XXX: We never get this from ICMP, otherwise it makes an
1316 * excellent DoS attack on machines with many connections.
1318 else if (cmd == PRC_HOSTDEAD)
1320 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
1323 icp = (struct icmp *)((caddr_t)ip
1324 - offsetof(struct icmp, icmp_ip));
1325 th = (struct tcphdr *)((caddr_t)ip
1326 + (ip->ip_hl << 2));
1327 INP_INFO_WLOCK(&V_tcbinfo);
1328 inp = in_pcblookup_hash(&V_tcbinfo, faddr, th->th_dport,
1329 ip->ip_src, th->th_sport, 0, NULL);
1332 if (!(inp->inp_flags & INP_TIMEWAIT) &&
1333 !(inp->inp_flags & INP_DROPPED) &&
1334 !(inp->inp_socket == NULL)) {
1335 icmp_tcp_seq = htonl(th->th_seq);
1336 tp = intotcpcb(inp);
1337 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) &&
1338 SEQ_LT(icmp_tcp_seq, tp->snd_max)) {
1339 if (cmd == PRC_MSGSIZE) {
1342 * If we got a needfrag set the MTU
1343 * in the route to the suggested new
1344 * value (if given) and then notify.
1346 bzero(&inc, sizeof(inc));
1347 inc.inc_faddr = faddr;
1349 inp->inp_inc.inc_fibnum;
1351 mtu = ntohs(icp->icmp_nextmtu);
1353 * If no alternative MTU was
1354 * proposed, try the next smaller
1355 * one. ip->ip_len has already
1356 * been swapped in icmp_input().
1359 mtu = ip_next_mtu(ip->ip_len,
1361 if (mtu < max(296, V_tcp_minmss
1362 + sizeof(struct tcpiphdr)))
1366 + sizeof(struct tcpiphdr);
1368 * Only cache the the MTU if it
1369 * is smaller than the interface
1370 * or route MTU. tcp_mtudisc()
1371 * will do right thing by itself.
1373 if (mtu <= tcp_maxmtu(&inc, NULL))
1374 tcp_hc_updatemtu(&inc, mtu);
1377 inp = (*notify)(inp, inetctlerrmap[cmd]);
1383 bzero(&inc, sizeof(inc));
1384 inc.inc_fport = th->th_dport;
1385 inc.inc_lport = th->th_sport;
1386 inc.inc_faddr = faddr;
1387 inc.inc_laddr = ip->ip_src;
1388 syncache_unreach(&inc, th);
1390 INP_INFO_WUNLOCK(&V_tcbinfo);
1392 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify);
1397 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
1400 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1401 struct ip6_hdr *ip6;
1403 struct ip6ctlparam *ip6cp = NULL;
1404 const struct sockaddr_in6 *sa6_src = NULL;
1406 struct tcp_portonly {
1411 if (sa->sa_family != AF_INET6 ||
1412 sa->sa_len != sizeof(struct sockaddr_in6))
1415 if (cmd == PRC_MSGSIZE)
1416 notify = tcp_mtudisc;
1417 else if (!PRC_IS_REDIRECT(cmd) &&
1418 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
1420 /* Source quench is depreciated. */
1421 else if (cmd == PRC_QUENCH)
1424 /* if the parameter is from icmp6, decode it. */
1426 ip6cp = (struct ip6ctlparam *)d;
1428 ip6 = ip6cp->ip6c_ip6;
1429 off = ip6cp->ip6c_off;
1430 sa6_src = ip6cp->ip6c_src;
1434 off = 0; /* fool gcc */
1439 struct in_conninfo inc;
1441 * XXX: We assume that when IPV6 is non NULL,
1442 * M and OFF are valid.
1445 /* check if we can safely examine src and dst ports */
1446 if (m->m_pkthdr.len < off + sizeof(*thp))
1449 bzero(&th, sizeof(th));
1450 m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
1452 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport,
1453 (struct sockaddr *)ip6cp->ip6c_src,
1454 th.th_sport, cmd, NULL, notify);
1456 bzero(&inc, sizeof(inc));
1457 inc.inc_fport = th.th_dport;
1458 inc.inc_lport = th.th_sport;
1459 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
1460 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
1461 inc.inc_flags |= INC_ISIPV6;
1462 INP_INFO_WLOCK(&V_tcbinfo);
1463 syncache_unreach(&inc, &th);
1464 INP_INFO_WUNLOCK(&V_tcbinfo);
1466 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src,
1467 0, cmd, NULL, notify);
1473 * Following is where TCP initial sequence number generation occurs.
1475 * There are two places where we must use initial sequence numbers:
1476 * 1. In SYN-ACK packets.
1477 * 2. In SYN packets.
1479 * All ISNs for SYN-ACK packets are generated by the syncache. See
1480 * tcp_syncache.c for details.
1482 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
1483 * depends on this property. In addition, these ISNs should be
1484 * unguessable so as to prevent connection hijacking. To satisfy
1485 * the requirements of this situation, the algorithm outlined in
1486 * RFC 1948 is used, with only small modifications.
1488 * Implementation details:
1490 * Time is based off the system timer, and is corrected so that it
1491 * increases by one megabyte per second. This allows for proper
1492 * recycling on high speed LANs while still leaving over an hour
1495 * As reading the *exact* system time is too expensive to be done
1496 * whenever setting up a TCP connection, we increment the time
1497 * offset in two ways. First, a small random positive increment
1498 * is added to isn_offset for each connection that is set up.
1499 * Second, the function tcp_isn_tick fires once per clock tick
1500 * and increments isn_offset as necessary so that sequence numbers
1501 * are incremented at approximately ISN_BYTES_PER_SECOND. The
1502 * random positive increments serve only to ensure that the same
1503 * exact sequence number is never sent out twice (as could otherwise
1504 * happen when a port is recycled in less than the system tick
1507 * net.inet.tcp.isn_reseed_interval controls the number of seconds
1508 * between seeding of isn_secret. This is normally set to zero,
1509 * as reseeding should not be necessary.
1511 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
1512 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In
1513 * general, this means holding an exclusive (write) lock.
1516 #define ISN_BYTES_PER_SECOND 1048576
1517 #define ISN_STATIC_INCREMENT 4096
1518 #define ISN_RANDOM_INCREMENT (4096 - 1)
1520 static VNET_DEFINE(u_char, isn_secret[32]);
1521 static VNET_DEFINE(int, isn_last_reseed);
1522 static VNET_DEFINE(u_int32_t, isn_offset);
1523 static VNET_DEFINE(u_int32_t, isn_offset_old);
1525 #define V_isn_secret VNET(isn_secret)
1526 #define V_isn_last_reseed VNET(isn_last_reseed)
1527 #define V_isn_offset VNET(isn_offset)
1528 #define V_isn_offset_old VNET(isn_offset_old)
1531 tcp_new_isn(struct tcpcb *tp)
1534 u_int32_t md5_buffer[4];
1537 INP_WLOCK_ASSERT(tp->t_inpcb);
1540 /* Seed if this is the first use, reseed if requested. */
1541 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) &&
1542 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz)
1544 read_random(&V_isn_secret, sizeof(V_isn_secret));
1545 V_isn_last_reseed = ticks;
1548 /* Compute the md5 hash and return the ISN. */
1550 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
1551 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
1553 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
1554 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
1555 sizeof(struct in6_addr));
1556 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
1557 sizeof(struct in6_addr));
1561 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
1562 sizeof(struct in_addr));
1563 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
1564 sizeof(struct in_addr));
1566 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret));
1567 MD5Final((u_char *) &md5_buffer, &isn_ctx);
1568 new_isn = (tcp_seq) md5_buffer[0];
1569 V_isn_offset += ISN_STATIC_INCREMENT +
1570 (arc4random() & ISN_RANDOM_INCREMENT);
1571 new_isn += V_isn_offset;
1577 * Increment the offset to the next ISN_BYTES_PER_SECOND / 100 boundary
1578 * to keep time flowing at a relatively constant rate. If the random
1579 * increments have already pushed us past the projected offset, do nothing.
1582 tcp_isn_tick(void *xtp)
1584 VNET_ITERATOR_DECL(vnet_iter);
1585 u_int32_t projected_offset;
1587 VNET_LIST_RLOCK_NOSLEEP();
1589 VNET_FOREACH(vnet_iter) {
1590 CURVNET_SET(vnet_iter); /* XXX appease INVARIANTS */
1592 V_isn_offset_old + ISN_BYTES_PER_SECOND / 100;
1594 if (SEQ_GT(projected_offset, V_isn_offset))
1595 V_isn_offset = projected_offset;
1597 V_isn_offset_old = V_isn_offset;
1601 VNET_LIST_RUNLOCK_NOSLEEP();
1602 callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL);
1606 * When a specific ICMP unreachable message is received and the
1607 * connection state is SYN-SENT, drop the connection. This behavior
1608 * is controlled by the icmp_may_rst sysctl.
1611 tcp_drop_syn_sent(struct inpcb *inp, int errno)
1615 INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
1616 INP_WLOCK_ASSERT(inp);
1618 if ((inp->inp_flags & INP_TIMEWAIT) ||
1619 (inp->inp_flags & INP_DROPPED))
1622 tp = intotcpcb(inp);
1623 if (tp->t_state != TCPS_SYN_SENT)
1626 tp = tcp_drop(tp, errno);
1634 * When `need fragmentation' ICMP is received, update our idea of the MSS
1635 * based on the new value in the route. Also nudge TCP to send something,
1636 * since we know the packet we just sent was dropped.
1637 * This duplicates some code in the tcp_mss() function in tcp_input.c.
1640 tcp_mtudisc(struct inpcb *inp, int errno)
1645 INP_WLOCK_ASSERT(inp);
1646 if ((inp->inp_flags & INP_TIMEWAIT) ||
1647 (inp->inp_flags & INP_DROPPED))
1650 tp = intotcpcb(inp);
1651 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
1653 tcp_mss_update(tp, -1, NULL, NULL);
1655 so = inp->inp_socket;
1656 SOCKBUF_LOCK(&so->so_snd);
1657 /* If the mss is larger than the socket buffer, decrease the mss. */
1658 if (so->so_snd.sb_hiwat < tp->t_maxseg)
1659 tp->t_maxseg = so->so_snd.sb_hiwat;
1660 SOCKBUF_UNLOCK(&so->so_snd);
1662 TCPSTAT_INC(tcps_mturesent);
1664 tp->snd_nxt = tp->snd_una;
1665 tcp_free_sackholes(tp);
1666 tp->snd_recover = tp->snd_max;
1667 if (tp->t_flags & TF_SACK_PERMIT)
1668 EXIT_FASTRECOVERY(tp);
1669 tcp_output_send(tp);
1674 * Look-up the routing entry to the peer of this inpcb. If no route
1675 * is found and it cannot be allocated, then return 0. This routine
1676 * is called by TCP routines that access the rmx structure and by
1677 * tcp_mss_update to get the peer/interface MTU.
1680 tcp_maxmtu(struct in_conninfo *inc, int *flags)
1683 struct sockaddr_in *dst;
1687 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
1689 bzero(&sro, sizeof(sro));
1690 if (inc->inc_faddr.s_addr != INADDR_ANY) {
1691 dst = (struct sockaddr_in *)&sro.ro_dst;
1692 dst->sin_family = AF_INET;
1693 dst->sin_len = sizeof(*dst);
1694 dst->sin_addr = inc->inc_faddr;
1695 in_rtalloc_ign(&sro, 0, inc->inc_fibnum);
1697 if (sro.ro_rt != NULL) {
1698 ifp = sro.ro_rt->rt_ifp;
1699 if (sro.ro_rt->rt_rmx.rmx_mtu == 0)
1700 maxmtu = ifp->if_mtu;
1702 maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu);
1704 /* Report additional interface capabilities. */
1705 if (flags != NULL) {
1706 if (ifp->if_capenable & IFCAP_TSO4 &&
1707 ifp->if_hwassist & CSUM_TSO)
1717 tcp_maxmtu6(struct in_conninfo *inc, int *flags)
1719 struct route_in6 sro6;
1723 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
1725 bzero(&sro6, sizeof(sro6));
1726 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
1727 sro6.ro_dst.sin6_family = AF_INET6;
1728 sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
1729 sro6.ro_dst.sin6_addr = inc->inc6_faddr;
1730 rtalloc_ign((struct route *)&sro6, 0);
1732 if (sro6.ro_rt != NULL) {
1733 ifp = sro6.ro_rt->rt_ifp;
1734 if (sro6.ro_rt->rt_rmx.rmx_mtu == 0)
1735 maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp);
1737 maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu,
1738 IN6_LINKMTU(sro6.ro_rt->rt_ifp));
1740 /* Report additional interface capabilities. */
1741 if (flags != NULL) {
1742 if (ifp->if_capenable & IFCAP_TSO6 &&
1743 ifp->if_hwassist & CSUM_TSO)
1754 /* compute ESP/AH header size for TCP, including outer IP header. */
1756 ipsec_hdrsiz_tcp(struct tcpcb *tp)
1763 struct ip6_hdr *ip6;
1767 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
1769 MGETHDR(m, M_DONTWAIT, MT_DATA);
1774 if ((inp->inp_vflag & INP_IPV6) != 0) {
1775 ip6 = mtod(m, struct ip6_hdr *);
1776 th = (struct tcphdr *)(ip6 + 1);
1777 m->m_pkthdr.len = m->m_len =
1778 sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1779 tcpip_fillheaders(inp, ip6, th);
1780 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1784 ip = mtod(m, struct ip *);
1785 th = (struct tcphdr *)(ip + 1);
1786 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
1787 tcpip_fillheaders(inp, ip, th);
1788 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1797 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
1799 * This code attempts to calculate the bandwidth-delay product as a
1800 * means of determining the optimal window size to maximize bandwidth,
1801 * minimize RTT, and avoid the over-allocation of buffers on interfaces and
1802 * routers. This code also does a fairly good job keeping RTTs in check
1803 * across slow links like modems. We implement an algorithm which is very
1804 * similar (but not meant to be) TCP/Vegas. The code operates on the
1805 * transmitter side of a TCP connection and so only effects the transmit
1806 * side of the connection.
1808 * BACKGROUND: TCP makes no provision for the management of buffer space
1809 * at the end points or at the intermediate routers and switches. A TCP
1810 * stream, whether using NewReno or not, will eventually buffer as
1811 * many packets as it is able and the only reason this typically works is
1812 * due to the fairly small default buffers made available for a connection
1813 * (typicaly 16K or 32K). As machines use larger windows and/or window
1814 * scaling it is now fairly easy for even a single TCP connection to blow-out
1815 * all available buffer space not only on the local interface, but on
1816 * intermediate routers and switches as well. NewReno makes a misguided
1817 * attempt to 'solve' this problem by waiting for an actual failure to occur,
1818 * then backing off, then steadily increasing the window again until another
1819 * failure occurs, ad-infinitum. This results in terrible oscillation that
1820 * is only made worse as network loads increase and the idea of intentionally
1821 * blowing out network buffers is, frankly, a terrible way to manage network
1824 * It is far better to limit the transmit window prior to the failure
1825 * condition being achieved. There are two general ways to do this: First
1826 * you can 'scan' through different transmit window sizes and locate the
1827 * point where the RTT stops increasing, indicating that you have filled the
1828 * pipe, then scan backwards until you note that RTT stops decreasing, then
1829 * repeat ad-infinitum. This method works in principle but has severe
1830 * implementation issues due to RTT variances, timer granularity, and
1831 * instability in the algorithm which can lead to many false positives and
1832 * create oscillations as well as interact badly with other TCP streams
1833 * implementing the same algorithm.
1835 * The second method is to limit the window to the bandwidth delay product
1836 * of the link. This is the method we implement. RTT variances and our
1837 * own manipulation of the congestion window, bwnd, can potentially
1838 * destabilize the algorithm. For this reason we have to stabilize the
1839 * elements used to calculate the window. We do this by using the minimum
1840 * observed RTT, the long term average of the observed bandwidth, and
1841 * by adding two segments worth of slop. It isn't perfect but it is able
1842 * to react to changing conditions and gives us a very stable basis on
1843 * which to extend the algorithm.
1846 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq)
1852 INP_WLOCK_ASSERT(tp->t_inpcb);
1855 * If inflight_enable is disabled in the middle of a tcp connection,
1856 * make sure snd_bwnd is effectively disabled.
1858 if (V_tcp_inflight_enable == 0 ||
1859 tp->t_rttlow < V_tcp_inflight_rttthresh) {
1860 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1861 tp->snd_bandwidth = 0;
1866 * Figure out the bandwidth. Due to the tick granularity this
1867 * is a very rough number and it MUST be averaged over a fairly
1868 * long period of time. XXX we need to take into account a link
1869 * that is not using all available bandwidth, but for now our
1870 * slop will ramp us up if this case occurs and the bandwidth later
1873 * Note: if ticks rollover 'bw' may wind up negative. We must
1874 * effectively reset t_bw_rtttime for this case.
1877 if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1)
1880 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz /
1881 (save_ticks - tp->t_bw_rtttime);
1882 tp->t_bw_rtttime = save_ticks;
1883 tp->t_bw_rtseq = ack_seq;
1884 if (tp->t_bw_rtttime == 0 || (int)bw < 0)
1886 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4;
1888 tp->snd_bandwidth = bw;
1891 * Calculate the semi-static bandwidth delay product, plus two maximal
1892 * segments. The additional slop puts us squarely in the sweet
1893 * spot and also handles the bandwidth run-up case and stabilization.
1894 * Without the slop we could be locking ourselves into a lower
1897 * Situations Handled:
1898 * (1) Prevents over-queueing of packets on LANs, especially on
1899 * high speed LANs, allowing larger TCP buffers to be
1900 * specified, and also does a good job preventing
1901 * over-queueing of packets over choke points like modems
1902 * (at least for the transmit side).
1904 * (2) Is able to handle changing network loads (bandwidth
1905 * drops so bwnd drops, bandwidth increases so bwnd
1908 * (3) Theoretically should stabilize in the face of multiple
1909 * connections implementing the same algorithm (this may need
1912 * (4) Stability value (defaults to 20 = 2 maximal packets) can
1913 * be adjusted with a sysctl but typically only needs to be
1914 * on very slow connections. A value no smaller then 5
1915 * should be used, but only reduce this default if you have
1918 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2)
1919 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + V_tcp_inflight_stab * tp->t_maxseg / 10;
1922 if (tcp_inflight_debug > 0) {
1924 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) {
1926 printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n",
1935 if ((long)bwnd < V_tcp_inflight_min)
1936 bwnd = V_tcp_inflight_min;
1937 if (bwnd > V_tcp_inflight_max)
1938 bwnd = V_tcp_inflight_max;
1939 if ((long)bwnd < tp->t_maxseg * 2)
1940 bwnd = tp->t_maxseg * 2;
1941 tp->snd_bwnd = bwnd;
1944 #ifdef TCP_SIGNATURE
1946 * Callback function invoked by m_apply() to digest TCP segment data
1947 * contained within an mbuf chain.
1950 tcp_signature_apply(void *fstate, void *data, u_int len)
1953 MD5Update(fstate, (u_char *)data, len);
1958 * Compute TCP-MD5 hash of a TCP segment. (RFC2385)
1961 * m pointer to head of mbuf chain
1963 * len length of TCP segment data, excluding options
1964 * optlen length of TCP segment options
1965 * buf pointer to storage for computed MD5 digest
1966 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND)
1968 * We do this over ip, tcphdr, segment data, and the key in the SADB.
1969 * When called from tcp_input(), we can be sure that th_sum has been
1970 * zeroed out and verified already.
1972 * Return 0 if successful, otherwise return -1.
1974 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a
1975 * search with the destination IP address, and a 'magic SPI' to be
1976 * determined by the application. This is hardcoded elsewhere to 1179
1977 * right now. Another branch of this code exists which uses the SPD to
1978 * specify per-application flows but it is unstable.
1981 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen,
1982 u_char *buf, u_int direction)
1984 union sockaddr_union dst;
1985 struct ippseudo ippseudo;
1989 struct ipovly *ipovly;
1990 struct secasvar *sav;
1993 struct ip6_hdr *ip6;
1994 struct in6_addr in6;
1995 char ip6buf[INET6_ADDRSTRLEN];
2001 KASSERT(m != NULL, ("NULL mbuf chain"));
2002 KASSERT(buf != NULL, ("NULL signature pointer"));
2004 /* Extract the destination from the IP header in the mbuf. */
2005 bzero(&dst, sizeof(union sockaddr_union));
2006 ip = mtod(m, struct ip *);
2008 ip6 = NULL; /* Make the compiler happy. */
2012 dst.sa.sa_len = sizeof(struct sockaddr_in);
2013 dst.sa.sa_family = AF_INET;
2014 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ?
2015 ip->ip_src : ip->ip_dst;
2018 case (IPV6_VERSION >> 4):
2019 ip6 = mtod(m, struct ip6_hdr *);
2020 dst.sa.sa_len = sizeof(struct sockaddr_in6);
2021 dst.sa.sa_family = AF_INET6;
2022 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ?
2023 ip6->ip6_src : ip6->ip6_dst;
2032 /* Look up an SADB entry which matches the address of the peer. */
2033 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI));
2035 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__,
2036 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) :
2038 (ip->ip_v == (IPV6_VERSION >> 4)) ?
2039 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) :
2047 * Step 1: Update MD5 hash with IP(v6) pseudo-header.
2049 * XXX The ippseudo header MUST be digested in network byte order,
2050 * or else we'll fail the regression test. Assume all fields we've
2051 * been doing arithmetic on have been in host byte order.
2052 * XXX One cannot depend on ipovly->ih_len here. When called from
2053 * tcp_output(), the underlying ip_len member has not yet been set.
2057 ipovly = (struct ipovly *)ip;
2058 ippseudo.ippseudo_src = ipovly->ih_src;
2059 ippseudo.ippseudo_dst = ipovly->ih_dst;
2060 ippseudo.ippseudo_pad = 0;
2061 ippseudo.ippseudo_p = IPPROTO_TCP;
2062 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) +
2064 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo));
2066 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip));
2067 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen;
2071 * RFC 2385, 2.0 Proposal
2072 * For IPv6, the pseudo-header is as described in RFC 2460, namely the
2073 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero-
2074 * extended next header value (to form 32 bits), and 32-bit segment
2076 * Note: Upper-Layer Packet Length comes before Next Header.
2078 case (IPV6_VERSION >> 4):
2080 in6_clearscope(&in6);
2081 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
2083 in6_clearscope(&in6);
2084 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
2085 plen = htonl(len + sizeof(struct tcphdr) + optlen);
2086 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t));
2088 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
2089 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
2090 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
2092 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
2094 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr));
2095 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen;
2106 * Step 2: Update MD5 hash with TCP header, excluding options.
2107 * The TCP checksum must be set to zero.
2109 savecsum = th->th_sum;
2111 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr));
2112 th->th_sum = savecsum;
2115 * Step 3: Update MD5 hash with TCP segment data.
2116 * Use m_apply() to avoid an early m_pullup().
2119 m_apply(m, doff, len, tcp_signature_apply, &ctx);
2122 * Step 4: Update MD5 hash with shared secret.
2124 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth));
2125 MD5Final(buf, &ctx);
2127 key_sa_recordxfer(sav, m);
2131 #endif /* TCP_SIGNATURE */
2134 sysctl_drop(SYSCTL_HANDLER_ARGS)
2136 /* addrs[0] is a foreign socket, addrs[1] is a local one. */
2137 struct sockaddr_storage addrs[2];
2141 struct sockaddr_in *fin, *lin;
2143 struct sockaddr_in6 *fin6, *lin6;
2154 if (req->oldptr != NULL || req->oldlen != 0)
2156 if (req->newptr == NULL)
2158 if (req->newlen < sizeof(addrs))
2160 error = SYSCTL_IN(req, &addrs, sizeof(addrs));
2164 switch (addrs[0].ss_family) {
2167 fin6 = (struct sockaddr_in6 *)&addrs[0];
2168 lin6 = (struct sockaddr_in6 *)&addrs[1];
2169 if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
2170 lin6->sin6_len != sizeof(struct sockaddr_in6))
2172 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
2173 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
2175 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
2176 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
2177 fin = (struct sockaddr_in *)&addrs[0];
2178 lin = (struct sockaddr_in *)&addrs[1];
2181 error = sa6_embedscope(fin6, V_ip6_use_defzone);
2184 error = sa6_embedscope(lin6, V_ip6_use_defzone);
2190 fin = (struct sockaddr_in *)&addrs[0];
2191 lin = (struct sockaddr_in *)&addrs[1];
2192 if (fin->sin_len != sizeof(struct sockaddr_in) ||
2193 lin->sin_len != sizeof(struct sockaddr_in))
2199 INP_INFO_WLOCK(&V_tcbinfo);
2200 switch (addrs[0].ss_family) {
2203 inp = in6_pcblookup_hash(&V_tcbinfo, &fin6->sin6_addr,
2204 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port, 0,
2209 inp = in_pcblookup_hash(&V_tcbinfo, fin->sin_addr,
2210 fin->sin_port, lin->sin_addr, lin->sin_port, 0, NULL);
2215 if (inp->inp_flags & INP_TIMEWAIT) {
2217 * XXXRW: There currently exists a state where an
2218 * inpcb is present, but its timewait state has been
2219 * discarded. For now, don't allow dropping of this
2227 } else if (!(inp->inp_flags & INP_DROPPED) &&
2228 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) {
2229 tp = intotcpcb(inp);
2230 tp = tcp_drop(tp, ECONNABORTED);
2237 INP_INFO_WUNLOCK(&V_tcbinfo);
2241 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
2242 CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL,
2243 0, sysctl_drop, "", "Drop TCP connection");
2246 * Generate a standardized TCP log line for use throughout the
2247 * tcp subsystem. Memory allocation is done with M_NOWAIT to
2248 * allow use in the interrupt context.
2250 * NB: The caller MUST free(s, M_TCPLOG) the returned string.
2251 * NB: The function may return NULL if memory allocation failed.
2253 * Due to header inclusion and ordering limitations the struct ip
2254 * and ip6_hdr pointers have to be passed as void pointers.
2257 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2264 const struct ip6_hdr *ip6;
2266 ip6 = (const struct ip6_hdr *)ip6hdr;
2268 ip = (struct ip *)ip4hdr;
2271 * The log line looks like this:
2272 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>"
2274 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") +
2275 sizeof(PRINT_TH_FLAGS) + 1 +
2277 2 * INET6_ADDRSTRLEN;
2279 2 * INET_ADDRSTRLEN;
2282 /* Is logging enabled? */
2283 if (tcp_log_debug == 0 && tcp_log_in_vain == 0)
2286 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT);
2290 strcat(s, "TCP: [");
2293 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) {
2294 inet_ntoa_r(inc->inc_faddr, sp);
2296 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2298 inet_ntoa_r(inc->inc_laddr, sp);
2300 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2303 ip6_sprintf(sp, &inc->inc6_faddr);
2305 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2307 ip6_sprintf(sp, &inc->inc6_laddr);
2309 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2310 } else if (ip6 && th) {
2311 ip6_sprintf(sp, &ip6->ip6_src);
2313 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2315 ip6_sprintf(sp, &ip6->ip6_dst);
2317 sprintf(sp, "]:%i", ntohs(th->th_dport));
2319 } else if (ip && th) {
2320 inet_ntoa_r(ip->ip_src, sp);
2322 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2324 inet_ntoa_r(ip->ip_dst, sp);
2326 sprintf(sp, "]:%i", ntohs(th->th_dport));
2333 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS);
2334 if (*(s + size - 1) != '\0')
2335 panic("%s: string too long", __func__);