2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved.
3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved.
5 * This code is derived from software contributed to The DragonFly Project
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
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15 * documentation and/or other materials provided with the distribution.
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17 * contributors may be used to endorse or promote products derived
18 * from this software without specific, prior written permission.
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39 * modification, are permitted provided that the following conditions
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63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
66 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
67 * $FreeBSD: src/sys/netinet/tcp_subr.c,v 1.73.2.31 2003/01/24 05:11:34 sam Exp $
68 * $DragonFly: src/sys/netinet/tcp_subr.c,v 1.61 2008/09/23 11:28:49 sephe Exp $
71 #include "opt_compat.h"
72 #include "opt_inet6.h"
73 #include "opt_ipsec.h"
74 #include "opt_tcpdebug.h"
76 #include <sys/param.h>
77 #include <sys/systm.h>
78 #include <sys/callout.h>
79 #include <sys/kernel.h>
80 #include <sys/sysctl.h>
81 #include <sys/malloc.h>
82 #include <sys/mpipe.h>
85 #include <sys/domain.h>
88 #include <sys/socket.h>
89 #include <sys/socketvar.h>
90 #include <sys/protosw.h>
91 #include <sys/random.h>
92 #include <sys/in_cksum.h>
95 #include <vm/vm_zone.h>
97 #include <net/route.h>
99 #include <net/netisr.h>
102 #include <netinet/in.h>
103 #include <netinet/in_systm.h>
104 #include <netinet/ip.h>
105 #include <netinet/ip6.h>
106 #include <netinet/in_pcb.h>
107 #include <netinet6/in6_pcb.h>
108 #include <netinet/in_var.h>
109 #include <netinet/ip_var.h>
110 #include <netinet6/ip6_var.h>
111 #include <netinet/ip_icmp.h>
113 #include <netinet/icmp6.h>
115 #include <netinet/tcp.h>
116 #include <netinet/tcp_fsm.h>
117 #include <netinet/tcp_seq.h>
118 #include <netinet/tcp_timer.h>
119 #include <netinet/tcp_var.h>
120 #include <netinet6/tcp6_var.h>
121 #include <netinet/tcpip.h>
123 #include <netinet/tcp_debug.h>
125 #include <netinet6/ip6protosw.h>
128 #include <netinet6/ipsec.h>
130 #include <netinet6/ipsec6.h>
135 #include <netproto/ipsec/ipsec.h>
137 #include <netproto/ipsec/ipsec6.h>
143 #include <sys/msgport2.h>
144 #include <machine/smp.h>
146 #include <net/netmsg2.h>
148 #if !defined(KTR_TCP)
149 #define KTR_TCP KTR_ALL
151 KTR_INFO_MASTER(tcp);
152 KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0);
153 KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0);
154 KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0);
155 #define logtcp(name) KTR_LOG(tcp_ ## name)
157 struct inpcbinfo tcbinfo[MAXCPU];
158 struct tcpcbackqhead tcpcbackq[MAXCPU];
160 int tcp_mpsafe_proto = 0;
161 TUNABLE_INT("net.inet.tcp.mpsafe_proto", &tcp_mpsafe_proto);
163 static int tcp_mpsafe_thread = 0;
164 TUNABLE_INT("net.inet.tcp.mpsafe_thread", &tcp_mpsafe_thread);
165 SYSCTL_INT(_net_inet_tcp, OID_AUTO, mpsafe_thread, CTLFLAG_RW,
166 &tcp_mpsafe_thread, 0,
167 "0:BGL, 1:Adaptive BGL, 2:No BGL(experimental)");
169 int tcp_mssdflt = TCP_MSS;
170 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW,
171 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size");
174 int tcp_v6mssdflt = TCP6_MSS;
175 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW,
176 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6");
180 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
181 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW,
182 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time");
185 int tcp_do_rfc1323 = 1;
186 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
187 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions");
189 int tcp_do_rfc1644 = 0;
190 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW,
191 &tcp_do_rfc1644, 0, "Enable rfc1644 (TTCP) extensions");
193 static int tcp_tcbhashsize = 0;
194 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD,
195 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable");
197 static int do_tcpdrain = 1;
198 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
199 "Enable tcp_drain routine for extra help when low on mbufs");
202 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
203 &tcbinfo[0].ipi_count, 0, "Number of active PCBs");
205 static int icmp_may_rst = 1;
206 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0,
207 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
209 static int tcp_isn_reseed_interval = 0;
210 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
211 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret");
214 * TCP bandwidth limiting sysctls. Note that the default lower bound of
215 * 1024 exists only for debugging. A good production default would be
216 * something like 6100.
218 static int tcp_inflight_enable = 0;
219 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW,
220 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting");
222 static int tcp_inflight_debug = 0;
223 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW,
224 &tcp_inflight_debug, 0, "Debug TCP inflight calculations");
226 static int tcp_inflight_min = 6144;
227 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW,
228 &tcp_inflight_min, 0, "Lower bound for TCP inflight window");
230 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT;
231 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW,
232 &tcp_inflight_max, 0, "Upper bound for TCP inflight window");
234 static int tcp_inflight_stab = 20;
235 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW,
236 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 2 packets)");
238 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives");
239 static struct malloc_pipe tcptemp_mpipe;
241 static void tcp_willblock(int);
242 static void tcp_cleartaocache (void);
243 static void tcp_notify (struct inpcb *, int);
245 struct tcp_stats tcpstats_percpu[MAXCPU];
248 sysctl_tcpstats(SYSCTL_HANDLER_ARGS)
252 for (cpu = 0; cpu < ncpus; ++cpu) {
253 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu],
254 sizeof(struct tcp_stats))))
256 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu],
257 sizeof(struct tcp_stats))))
263 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW),
264 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics");
266 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW,
267 &tcpstat, tcp_stats, "TCP statistics");
271 * Target size of TCP PCB hash tables. Must be a power of two.
273 * Note that this can be overridden by the kernel environment
274 * variable net.inet.tcp.tcbhashsize
277 #define TCBHASHSIZE 512
281 * This is the actual shape of what we allocate using the zone
282 * allocator. Doing it this way allows us to protect both structures
283 * using the same generation count, and also eliminates the overhead
284 * of allocating tcpcbs separately. By hiding the structure here,
285 * we avoid changing most of the rest of the code (although it needs
286 * to be changed, eventually, for greater efficiency).
289 #define ALIGNM1 (ALIGNMENT - 1)
293 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1];
296 struct callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl;
297 struct callout inp_tp_delack;
308 struct inpcbporthead *porthashbase;
310 struct vm_zone *ipi_zone;
311 int hashsize = TCBHASHSIZE;
315 * note: tcptemp is used for keepalives, and it is ok for an
316 * allocation to fail so do not specify MPF_INT.
318 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp),
324 tcp_delacktime = TCPTV_DELACK;
325 tcp_keepinit = TCPTV_KEEP_INIT;
326 tcp_keepidle = TCPTV_KEEP_IDLE;
327 tcp_keepintvl = TCPTV_KEEPINTVL;
328 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
330 tcp_rexmit_min = TCPTV_MIN;
331 tcp_rexmit_slop = TCPTV_CPU_VAR;
333 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
334 if (!powerof2(hashsize)) {
335 kprintf("WARNING: TCB hash size not a power of 2\n");
336 hashsize = 512; /* safe default */
338 tcp_tcbhashsize = hashsize;
339 porthashbase = hashinit(hashsize, M_PCB, &porthashmask);
340 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets,
343 for (cpu = 0; cpu < ncpus2; cpu++) {
344 in_pcbinfo_init(&tcbinfo[cpu]);
345 tcbinfo[cpu].cpu = cpu;
346 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB,
347 &tcbinfo[cpu].hashmask);
348 tcbinfo[cpu].porthashbase = porthashbase;
349 tcbinfo[cpu].porthashmask = porthashmask;
350 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB,
351 &tcbinfo[cpu].wildcardhashmask);
352 tcbinfo[cpu].ipi_zone = ipi_zone;
353 TAILQ_INIT(&tcpcbackq[cpu]);
356 tcp_reass_maxseg = nmbclusters / 16;
357 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg);
360 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
362 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
364 if (max_protohdr < TCP_MINPROTOHDR)
365 max_protohdr = TCP_MINPROTOHDR;
366 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
368 #undef TCP_MINPROTOHDR
371 * Initialize TCP statistics counters for each CPU.
374 for (cpu = 0; cpu < ncpus; ++cpu) {
375 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats));
378 bzero(&tcpstat, sizeof(struct tcp_stats));
386 tcpmsg_service_loop(void *dummy)
392 * Thread was started with TDF_MPSAFE
396 while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) {
399 mplocked = netmsg_service(msg, tcp_mpsafe_thread,
401 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL);
404 tcp_willblock(mplocked);
410 tcp_willblock(int mplocked)
413 int cpu = mycpu->gd_cpuid;
416 if (!mplocked && !tcp_mpsafe_proto) {
417 if (TAILQ_EMPTY(&tcpcbackq[cpu]))
425 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) {
426 KKASSERT(tp->t_flags & TF_ONOUTPUTQ);
427 tp->t_flags &= ~TF_ONOUTPUTQ;
428 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq);
438 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
439 * tcp_template used to store this data in mbufs, but we now recopy it out
440 * of the tcpcb each time to conserve mbufs.
443 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr)
445 struct inpcb *inp = tp->t_inpcb;
446 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr;
449 if (inp->inp_vflag & INP_IPV6) {
452 ip6 = (struct ip6_hdr *)ip_ptr;
453 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
454 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK);
455 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
456 (IPV6_VERSION & IPV6_VERSION_MASK);
457 ip6->ip6_nxt = IPPROTO_TCP;
458 ip6->ip6_plen = sizeof(struct tcphdr);
459 ip6->ip6_src = inp->in6p_laddr;
460 ip6->ip6_dst = inp->in6p_faddr;
465 struct ip *ip = (struct ip *) ip_ptr;
467 ip->ip_vhl = IP_VHL_BORING;
474 ip->ip_p = IPPROTO_TCP;
475 ip->ip_src = inp->inp_laddr;
476 ip->ip_dst = inp->inp_faddr;
477 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr,
479 htons(sizeof(struct tcphdr) + IPPROTO_TCP));
482 tcp_hdr->th_sport = inp->inp_lport;
483 tcp_hdr->th_dport = inp->inp_fport;
488 tcp_hdr->th_flags = 0;
494 * Create template to be used to send tcp packets on a connection.
495 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
496 * use for this function is in keepalives, which use tcp_respond.
499 tcp_maketemplate(struct tcpcb *tp)
503 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL)
505 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t);
510 tcp_freetemplate(struct tcptemp *tmp)
512 mpipe_free(&tcptemp_mpipe, tmp);
516 * Send a single message to the TCP at address specified by
517 * the given TCP/IP header. If m == NULL, then we make a copy
518 * of the tcpiphdr at ti and send directly to the addressed host.
519 * This is used to force keep alive messages out using the TCP
520 * template for a connection. If flags are given then we send
521 * a message back to the TCP which originated the * segment ti,
522 * and discard the mbuf containing it and any other attached mbufs.
524 * In any case the ack and sequence number of the transmitted
525 * segment are as specified by the parameters.
527 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
530 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
531 tcp_seq ack, tcp_seq seq, int flags)
535 struct route *ro = NULL;
537 struct ip *ip = ipgen;
540 struct route_in6 *ro6 = NULL;
541 struct route_in6 sro6;
542 struct ip6_hdr *ip6 = ipgen;
544 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6);
546 const boolean_t isipv6 = FALSE;
550 if (!(flags & TH_RST)) {
551 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv);
552 if (win > (long)TCP_MAXWIN << tp->rcv_scale)
553 win = (long)TCP_MAXWIN << tp->rcv_scale;
556 ro6 = &tp->t_inpcb->in6p_route;
558 ro = &tp->t_inpcb->inp_route;
562 bzero(ro6, sizeof *ro6);
565 bzero(ro, sizeof *ro);
569 m = m_gethdr(MB_DONTWAIT, MT_HEADER);
573 m->m_data += max_linkhdr;
575 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr));
576 ip6 = mtod(m, struct ip6_hdr *);
577 nth = (struct tcphdr *)(ip6 + 1);
579 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
580 ip = mtod(m, struct ip *);
581 nth = (struct tcphdr *)(ip + 1);
583 bcopy(th, nth, sizeof(struct tcphdr));
588 m->m_data = (caddr_t)ipgen;
589 /* m_len is set later */
591 #define xchg(a, b, type) { type t; t = a; a = b; b = t; }
593 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
594 nth = (struct tcphdr *)(ip6 + 1);
596 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long);
597 nth = (struct tcphdr *)(ip + 1);
601 * this is usually a case when an extension header
602 * exists between the IPv6 header and the
605 nth->th_sport = th->th_sport;
606 nth->th_dport = th->th_dport;
608 xchg(nth->th_dport, nth->th_sport, n_short);
613 ip6->ip6_vfc = IPV6_VERSION;
614 ip6->ip6_nxt = IPPROTO_TCP;
615 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen));
616 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
618 tlen += sizeof(struct tcpiphdr);
620 ip->ip_ttl = ip_defttl;
623 m->m_pkthdr.len = tlen;
624 m->m_pkthdr.rcvif = (struct ifnet *) NULL;
625 nth->th_seq = htonl(seq);
626 nth->th_ack = htonl(ack);
628 nth->th_off = sizeof(struct tcphdr) >> 2;
629 nth->th_flags = flags;
631 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
633 nth->th_win = htons((u_short)win);
637 nth->th_sum = in6_cksum(m, IPPROTO_TCP,
638 sizeof(struct ip6_hdr),
639 tlen - sizeof(struct ip6_hdr));
640 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL,
641 (ro6 && ro6->ro_rt) ?
642 ro6->ro_rt->rt_ifp : NULL);
644 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
645 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
646 m->m_pkthdr.csum_flags = CSUM_TCP;
647 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
650 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
651 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
654 ip6_output(m, NULL, ro6, ipflags, NULL, NULL,
655 tp ? tp->t_inpcb : NULL);
656 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) {
661 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL);
662 if ((ro == &sro) && (ro->ro_rt != NULL)) {
670 * Create a new TCP control block, making an
671 * empty reassembly queue and hooking it to the argument
672 * protocol control block. The `inp' parameter must have
673 * come from the zone allocator set up in tcp_init().
676 tcp_newtcpcb(struct inpcb *inp)
681 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0);
683 const boolean_t isipv6 = FALSE;
686 it = (struct inp_tp *)inp;
688 bzero(tp, sizeof(struct tcpcb));
689 LIST_INIT(&tp->t_segq);
690 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt;
692 /* Set up our timeouts. */
693 callout_init(tp->tt_rexmt = &it->inp_tp_rexmt);
694 callout_init(tp->tt_persist = &it->inp_tp_persist);
695 callout_init(tp->tt_keep = &it->inp_tp_keep);
696 callout_init(tp->tt_2msl = &it->inp_tp_2msl);
697 callout_init(tp->tt_delack = &it->inp_tp_delack);
700 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP);
702 tp->t_flags |= TF_REQ_CC;
703 tp->t_inpcb = inp; /* XXX */
704 tp->t_state = TCPS_CLOSED;
706 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
707 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
708 * reasonable initial retransmit time.
710 tp->t_srtt = TCPTV_SRTTBASE;
712 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
713 tp->t_rttmin = tcp_rexmit_min;
714 tp->t_rxtcur = TCPTV_RTOBASE;
715 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
716 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
717 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
718 tp->t_rcvtime = ticks;
720 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
721 * because the socket may be bound to an IPv6 wildcard address,
722 * which may match an IPv4-mapped IPv6 address.
724 inp->inp_ip_ttl = ip_defttl;
726 tcp_sack_tcpcb_init(tp);
727 return (tp); /* XXX */
731 * Drop a TCP connection, reporting the specified error.
732 * If connection is synchronized, then send a RST to peer.
735 tcp_drop(struct tcpcb *tp, int error)
737 struct socket *so = tp->t_inpcb->inp_socket;
739 if (TCPS_HAVERCVDSYN(tp->t_state)) {
740 tp->t_state = TCPS_CLOSED;
742 tcpstat.tcps_drops++;
744 tcpstat.tcps_conndrops++;
745 if (error == ETIMEDOUT && tp->t_softerror)
746 error = tp->t_softerror;
747 so->so_error = error;
748 return (tcp_close(tp));
753 struct netmsg_remwildcard {
754 struct netmsg nm_netmsg;
755 struct inpcb *nm_inp;
756 struct inpcbinfo *nm_pcbinfo;
765 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the
766 * inp can be detached. We do this by cycling through the cpus, ending up
767 * on the cpu controlling the inp last and then doing the disconnect.
770 in_pcbremwildcardhash_handler(struct netmsg *msg0)
772 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0;
775 cpu = msg->nm_pcbinfo->cpu;
777 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) {
778 /* note: detach removes any wildcard hash entry */
781 in6_pcbdetach(msg->nm_inp);
784 in_pcbdetach(msg->nm_inp);
785 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0);
787 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo);
788 cpu = (cpu + 1) % ncpus2;
789 msg->nm_pcbinfo = &tcbinfo[cpu];
790 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg);
797 * Close a TCP control block:
798 * discard all space held by the tcp
799 * discard internet protocol block
800 * wake up any sleepers
803 tcp_close(struct tcpcb *tp)
806 struct inpcb *inp = tp->t_inpcb;
807 struct socket *so = inp->inp_socket;
809 boolean_t dosavessthresh;
814 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0);
815 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0);
817 const boolean_t isipv6 = FALSE;
821 * The tp is not instantly destroyed in the wildcard case. Setting
822 * the state to TCPS_TERMINATING will prevent the TCP stack from
823 * messing with it, though it should be noted that this change may
824 * not take effect on other cpus until we have chained the wildcard
827 * XXX we currently depend on the BGL to synchronize the tp->t_state
828 * update and prevent other tcp protocol threads from accepting new
829 * connections on the listen socket we might be trying to close down.
831 KKASSERT(tp->t_state != TCPS_TERMINATING);
832 tp->t_state = TCPS_TERMINATING;
835 * Make sure that all of our timers are stopped before we
838 callout_stop(tp->tt_rexmt);
839 callout_stop(tp->tt_persist);
840 callout_stop(tp->tt_keep);
841 callout_stop(tp->tt_2msl);
842 callout_stop(tp->tt_delack);
844 if (tp->t_flags & TF_ONOUTPUTQ) {
845 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid);
846 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq);
847 tp->t_flags &= ~TF_ONOUTPUTQ;
851 * If we got enough samples through the srtt filter,
852 * save the rtt and rttvar in the routing entry.
853 * 'Enough' is arbitrarily defined as the 16 samples.
854 * 16 samples is enough for the srtt filter to converge
855 * to within 5% of the correct value; fewer samples and
856 * we could save a very bogus rtt.
858 * Don't update the default route's characteristics and don't
859 * update anything that the user "locked".
861 if (tp->t_rttupdated >= 16) {
865 struct sockaddr_in6 *sin6;
867 if ((rt = inp->in6p_route.ro_rt) == NULL)
869 sin6 = (struct sockaddr_in6 *)rt_key(rt);
870 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr))
873 if ((rt = inp->inp_route.ro_rt) == NULL ||
874 ((struct sockaddr_in *)rt_key(rt))->
875 sin_addr.s_addr == INADDR_ANY)
878 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) {
879 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE));
880 if (rt->rt_rmx.rmx_rtt && i)
882 * filter this update to half the old & half
883 * the new values, converting scale.
884 * See route.h and tcp_var.h for a
885 * description of the scaling constants.
888 (rt->rt_rmx.rmx_rtt + i) / 2;
890 rt->rt_rmx.rmx_rtt = i;
891 tcpstat.tcps_cachedrtt++;
893 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) {
895 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE));
896 if (rt->rt_rmx.rmx_rttvar && i)
897 rt->rt_rmx.rmx_rttvar =
898 (rt->rt_rmx.rmx_rttvar + i) / 2;
900 rt->rt_rmx.rmx_rttvar = i;
901 tcpstat.tcps_cachedrttvar++;
904 * The old comment here said:
905 * update the pipelimit (ssthresh) if it has been updated
906 * already or if a pipesize was specified & the threshhold
907 * got below half the pipesize. I.e., wait for bad news
908 * before we start updating, then update on both good
911 * But we want to save the ssthresh even if no pipesize is
912 * specified explicitly in the route, because such
913 * connections still have an implicit pipesize specified
914 * by the global tcp_sendspace. In the absence of a reliable
915 * way to calculate the pipesize, it will have to do.
917 i = tp->snd_ssthresh;
918 if (rt->rt_rmx.rmx_sendpipe != 0)
919 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2);
921 dosavessthresh = (i < so->so_snd.ssb_hiwat/2);
922 if (dosavessthresh ||
923 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) &&
924 (rt->rt_rmx.rmx_ssthresh != 0))) {
926 * convert the limit from user data bytes to
927 * packets then to packet data bytes.
929 i = (i + tp->t_maxseg / 2) / tp->t_maxseg;
934 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
935 sizeof(struct tcpiphdr));
936 if (rt->rt_rmx.rmx_ssthresh)
937 rt->rt_rmx.rmx_ssthresh =
938 (rt->rt_rmx.rmx_ssthresh + i) / 2;
940 rt->rt_rmx.rmx_ssthresh = i;
941 tcpstat.tcps_cachedssthresh++;
946 /* free the reassembly queue, if any */
947 while((q = LIST_FIRST(&tp->t_segq)) != NULL) {
948 LIST_REMOVE(q, tqe_q);
953 /* throw away SACK blocks in scoreboard*/
955 tcp_sack_cleanup(&tp->scb);
957 inp->inp_ppcb = NULL;
958 soisdisconnected(so);
960 * Discard the inp. In the SMP case a wildcard inp's hash (created
961 * by a listen socket or an INADDR_ANY udp socket) is replicated
962 * for each protocol thread and must be removed in the context of
963 * that thread. This is accomplished by chaining the message
966 * If the inp is not wildcarded we simply detach, which will remove
967 * the any hashes still present for this inp.
970 if (inp->inp_flags & INP_WILDCARD_MP) {
971 struct netmsg_remwildcard *msg;
973 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2;
974 msg = kmalloc(sizeof(struct netmsg_remwildcard),
975 M_LWKTMSG, M_INTWAIT);
976 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0,
977 in_pcbremwildcardhash_handler);
979 msg->nm_isinet6 = isafinet6;
982 msg->nm_pcbinfo = &tcbinfo[cpu];
983 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg);
987 /* note: detach removes any wildcard hash entry */
995 tcpstat.tcps_closed++;
1000 tcp_drain_oncpu(struct inpcbhead *head)
1004 struct tseg_qent *te;
1006 LIST_FOREACH(inpb, head, inp_list) {
1007 if (inpb->inp_flags & INP_PLACEMARKER)
1009 if ((tcpb = intotcpcb(inpb))) {
1010 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) {
1011 LIST_REMOVE(te, tqe_q);
1021 struct netmsg_tcp_drain {
1022 struct netmsg nm_netmsg;
1023 struct inpcbhead *nm_head;
1027 tcp_drain_handler(netmsg_t netmsg)
1029 struct netmsg_tcp_drain *nm = (void *)netmsg;
1031 tcp_drain_oncpu(nm->nm_head);
1032 lwkt_replymsg(&nm->nm_netmsg.nm_lmsg, 0);
1047 * Walk the tcpbs, if existing, and flush the reassembly queue,
1048 * if there is one...
1049 * XXX: The "Net/3" implementation doesn't imply that the TCP
1050 * reassembly queue should be flushed, but in a situation
1051 * where we're really low on mbufs, this is potentially
1055 for (cpu = 0; cpu < ncpus2; cpu++) {
1056 struct netmsg_tcp_drain *msg;
1058 if (cpu == mycpu->gd_cpuid) {
1059 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead);
1061 msg = kmalloc(sizeof(struct netmsg_tcp_drain),
1062 M_LWKTMSG, M_NOWAIT);
1065 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0,
1067 msg->nm_head = &tcbinfo[cpu].pcblisthead;
1068 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg);
1072 tcp_drain_oncpu(&tcbinfo[0].pcblisthead);
1077 * Notify a tcp user of an asynchronous error;
1078 * store error as soft error, but wake up user
1079 * (for now, won't do anything until can select for soft error).
1081 * Do not wake up user since there currently is no mechanism for
1082 * reporting soft errors (yet - a kqueue filter may be added).
1085 tcp_notify(struct inpcb *inp, int error)
1087 struct tcpcb *tp = intotcpcb(inp);
1090 * Ignore some errors if we are hooked up.
1091 * If connection hasn't completed, has retransmitted several times,
1092 * and receives a second error, give up now. This is better
1093 * than waiting a long time to establish a connection that
1094 * can never complete.
1096 if (tp->t_state == TCPS_ESTABLISHED &&
1097 (error == EHOSTUNREACH || error == ENETUNREACH ||
1098 error == EHOSTDOWN)) {
1100 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
1102 tcp_drop(tp, error);
1104 tp->t_softerror = error;
1106 wakeup(&so->so_timeo);
1113 tcp_pcblist(SYSCTL_HANDLER_ARGS)
1116 struct inpcb *marker;
1126 * The process of preparing the TCB list is too time-consuming and
1127 * resource-intensive to repeat twice on every request.
1129 if (req->oldptr == NULL) {
1130 for (ccpu = 0; ccpu < ncpus; ++ccpu) {
1131 gd = globaldata_find(ccpu);
1132 n += tcbinfo[gd->gd_cpuid].ipi_count;
1134 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb);
1138 if (req->newptr != NULL)
1141 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO);
1142 marker->inp_flags |= INP_PLACEMARKER;
1145 * OK, now we're committed to doing something. Run the inpcb list
1146 * for each cpu in the system and construct the output. Use a
1147 * list placemarker to deal with list changes occuring during
1148 * copyout blockages (but otherwise depend on being on the correct
1149 * cpu to avoid races).
1151 origcpu = mycpu->gd_cpuid;
1152 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) {
1158 cpu_id = (origcpu + ccpu) % ncpus;
1159 if ((smp_active_mask & (1 << cpu_id)) == 0)
1161 rgd = globaldata_find(cpu_id);
1162 lwkt_setcpu_self(rgd);
1164 gencnt = tcbinfo[cpu_id].ipi_gencnt;
1165 n = tcbinfo[cpu_id].ipi_count;
1167 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list);
1169 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) {
1171 * process a snapshot of pcbs, ignoring placemarkers
1172 * and using our own to allow SYSCTL_OUT to block.
1174 LIST_REMOVE(marker, inp_list);
1175 LIST_INSERT_AFTER(inp, marker, inp_list);
1177 if (inp->inp_flags & INP_PLACEMARKER)
1179 if (inp->inp_gencnt > gencnt)
1181 if (prison_xinpcb(req->td, inp))
1184 xt.xt_len = sizeof xt;
1185 bcopy(inp, &xt.xt_inp, sizeof *inp);
1186 inp_ppcb = inp->inp_ppcb;
1187 if (inp_ppcb != NULL)
1188 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
1190 bzero(&xt.xt_tp, sizeof xt.xt_tp);
1191 if (inp->inp_socket)
1192 sotoxsocket(inp->inp_socket, &xt.xt_socket);
1193 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0)
1197 LIST_REMOVE(marker, inp_list);
1198 if (error == 0 && i < n) {
1199 bzero(&xt, sizeof xt);
1200 xt.xt_len = sizeof xt;
1202 error = SYSCTL_OUT(req, &xt, sizeof xt);
1211 * Make sure we are on the same cpu we were on originally, since
1212 * higher level callers expect this. Also don't pollute caches with
1213 * migrated userland data by (eventually) returning to userland
1214 * on a different cpu.
1216 lwkt_setcpu_self(globaldata_find(origcpu));
1217 kfree(marker, M_TEMP);
1221 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
1222 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
1225 tcp_getcred(SYSCTL_HANDLER_ARGS)
1227 struct sockaddr_in addrs[2];
1232 error = suser(req->td);
1235 error = SYSCTL_IN(req, addrs, sizeof addrs);
1239 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port,
1240 addrs[0].sin_addr.s_addr, addrs[0].sin_port);
1241 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr,
1242 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
1243 if (inp == NULL || inp->inp_socket == NULL) {
1247 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
1253 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW),
1254 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection");
1258 tcp6_getcred(SYSCTL_HANDLER_ARGS)
1260 struct sockaddr_in6 addrs[2];
1263 boolean_t mapped = FALSE;
1265 error = suser(req->td);
1268 error = SYSCTL_IN(req, addrs, sizeof addrs);
1271 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
1272 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
1279 inp = in_pcblookup_hash(&tcbinfo[0],
1280 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
1282 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
1286 inp = in6_pcblookup_hash(&tcbinfo[0],
1287 &addrs[1].sin6_addr, addrs[1].sin6_port,
1288 &addrs[0].sin6_addr, addrs[0].sin6_port,
1291 if (inp == NULL || inp->inp_socket == NULL) {
1295 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
1301 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW),
1303 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection");
1307 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
1309 struct ip *ip = vip;
1311 struct in_addr faddr;
1314 void (*notify)(struct inpcb *, int) = tcp_notify;
1318 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) {
1322 faddr = ((struct sockaddr_in *)sa)->sin_addr;
1323 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
1326 arg = inetctlerrmap[cmd];
1327 if (cmd == PRC_QUENCH) {
1328 notify = tcp_quench;
1329 } else if (icmp_may_rst &&
1330 (cmd == PRC_UNREACH_ADMIN_PROHIB ||
1331 cmd == PRC_UNREACH_PORT ||
1332 cmd == PRC_TIMXCEED_INTRANS) &&
1334 notify = tcp_drop_syn_sent;
1335 } else if (cmd == PRC_MSGSIZE) {
1336 struct icmp *icmp = (struct icmp *)
1337 ((caddr_t)ip - offsetof(struct icmp, icmp_ip));
1339 arg = ntohs(icmp->icmp_nextmtu);
1340 notify = tcp_mtudisc;
1341 } else if (PRC_IS_REDIRECT(cmd)) {
1343 notify = in_rtchange;
1344 } else if (cmd == PRC_HOSTDEAD) {
1350 th = (struct tcphdr *)((caddr_t)ip +
1351 (IP_VHL_HL(ip->ip_vhl) << 2));
1352 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport,
1353 ip->ip_src.s_addr, th->th_sport);
1354 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport,
1355 ip->ip_src, th->th_sport, 0, NULL);
1356 if ((inp != NULL) && (inp->inp_socket != NULL)) {
1357 icmpseq = htonl(th->th_seq);
1358 tp = intotcpcb(inp);
1359 if (SEQ_GEQ(icmpseq, tp->snd_una) &&
1360 SEQ_LT(icmpseq, tp->snd_max))
1361 (*notify)(inp, arg);
1363 struct in_conninfo inc;
1365 inc.inc_fport = th->th_dport;
1366 inc.inc_lport = th->th_sport;
1367 inc.inc_faddr = faddr;
1368 inc.inc_laddr = ip->ip_src;
1372 syncache_unreach(&inc, th);
1376 for (cpu = 0; cpu < ncpus2; cpu++) {
1377 in_pcbnotifyall(&tcbinfo[cpu].pcblisthead, faddr, arg,
1385 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
1388 void (*notify) (struct inpcb *, int) = tcp_notify;
1389 struct ip6_hdr *ip6;
1391 struct ip6ctlparam *ip6cp = NULL;
1392 const struct sockaddr_in6 *sa6_src = NULL;
1394 struct tcp_portonly {
1400 if (sa->sa_family != AF_INET6 ||
1401 sa->sa_len != sizeof(struct sockaddr_in6))
1405 if (cmd == PRC_QUENCH)
1406 notify = tcp_quench;
1407 else if (cmd == PRC_MSGSIZE) {
1408 struct ip6ctlparam *ip6cp = d;
1409 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
1411 arg = ntohl(icmp6->icmp6_mtu);
1412 notify = tcp_mtudisc;
1413 } else if (!PRC_IS_REDIRECT(cmd) &&
1414 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) {
1418 /* if the parameter is from icmp6, decode it. */
1420 ip6cp = (struct ip6ctlparam *)d;
1422 ip6 = ip6cp->ip6c_ip6;
1423 off = ip6cp->ip6c_off;
1424 sa6_src = ip6cp->ip6c_src;
1428 off = 0; /* fool gcc */
1433 struct in_conninfo inc;
1435 * XXX: We assume that when IPV6 is non NULL,
1436 * M and OFF are valid.
1439 /* check if we can safely examine src and dst ports */
1440 if (m->m_pkthdr.len < off + sizeof *thp)
1443 bzero(&th, sizeof th);
1444 m_copydata(m, off, sizeof *thp, (caddr_t)&th);
1446 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport,
1447 (struct sockaddr *)ip6cp->ip6c_src,
1448 th.th_sport, cmd, arg, notify);
1450 inc.inc_fport = th.th_dport;
1451 inc.inc_lport = th.th_sport;
1452 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
1453 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
1455 syncache_unreach(&inc, &th);
1457 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0,
1458 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify);
1463 * Following is where TCP initial sequence number generation occurs.
1465 * There are two places where we must use initial sequence numbers:
1466 * 1. In SYN-ACK packets.
1467 * 2. In SYN packets.
1469 * All ISNs for SYN-ACK packets are generated by the syncache. See
1470 * tcp_syncache.c for details.
1472 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
1473 * depends on this property. In addition, these ISNs should be
1474 * unguessable so as to prevent connection hijacking. To satisfy
1475 * the requirements of this situation, the algorithm outlined in
1476 * RFC 1948 is used to generate sequence numbers.
1478 * Implementation details:
1480 * Time is based off the system timer, and is corrected so that it
1481 * increases by one megabyte per second. This allows for proper
1482 * recycling on high speed LANs while still leaving over an hour
1485 * net.inet.tcp.isn_reseed_interval controls the number of seconds
1486 * between seeding of isn_secret. This is normally set to zero,
1487 * as reseeding should not be necessary.
1491 #define ISN_BYTES_PER_SECOND 1048576
1493 u_char isn_secret[32];
1494 int isn_last_reseed;
1498 tcp_new_isn(struct tcpcb *tp)
1500 u_int32_t md5_buffer[4];
1503 /* Seed if this is the first use, reseed if requested. */
1504 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) &&
1505 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz)
1507 read_random_unlimited(&isn_secret, sizeof isn_secret);
1508 isn_last_reseed = ticks;
1511 /* Compute the md5 hash and return the ISN. */
1513 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short));
1514 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short));
1516 if (tp->t_inpcb->inp_vflag & INP_IPV6) {
1517 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
1518 sizeof(struct in6_addr));
1519 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
1520 sizeof(struct in6_addr));
1524 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
1525 sizeof(struct in_addr));
1526 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
1527 sizeof(struct in_addr));
1529 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret));
1530 MD5Final((u_char *) &md5_buffer, &isn_ctx);
1531 new_isn = (tcp_seq) md5_buffer[0];
1532 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz);
1537 * When a source quench is received, close congestion window
1538 * to one segment. We will gradually open it again as we proceed.
1541 tcp_quench(struct inpcb *inp, int error)
1543 struct tcpcb *tp = intotcpcb(inp);
1546 tp->snd_cwnd = tp->t_maxseg;
1552 * When a specific ICMP unreachable message is received and the
1553 * connection state is SYN-SENT, drop the connection. This behavior
1554 * is controlled by the icmp_may_rst sysctl.
1557 tcp_drop_syn_sent(struct inpcb *inp, int error)
1559 struct tcpcb *tp = intotcpcb(inp);
1561 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT))
1562 tcp_drop(tp, error);
1566 * When a `need fragmentation' ICMP is received, update our idea of the MSS
1567 * based on the new value in the route. Also nudge TCP to send something,
1568 * since we know the packet we just sent was dropped.
1569 * This duplicates some code in the tcp_mss() function in tcp_input.c.
1572 tcp_mtudisc(struct inpcb *inp, int mtu)
1574 struct tcpcb *tp = intotcpcb(inp);
1576 struct socket *so = inp->inp_socket;
1579 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0);
1581 const boolean_t isipv6 = FALSE;
1588 * If no MTU is provided in the ICMP message, use the
1589 * next lower likely value, as specified in RFC 1191.
1594 oldmtu = tp->t_maxopd +
1596 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1597 sizeof(struct tcpiphdr));
1598 mtu = ip_next_mtu(oldmtu, 0);
1602 rt = tcp_rtlookup6(&inp->inp_inc);
1604 rt = tcp_rtlookup(&inp->inp_inc);
1606 struct rmxp_tao *taop = rmx_taop(rt->rt_rmx);
1608 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu)
1609 mtu = rt->rt_rmx.rmx_mtu;
1613 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1614 sizeof(struct tcpiphdr));
1617 * XXX - The following conditional probably violates the TCP
1618 * spec. The problem is that, since we don't know the
1619 * other end's MSS, we are supposed to use a conservative
1620 * default. But, if we do that, then MTU discovery will
1621 * never actually take place, because the conservative
1622 * default is much less than the MTUs typically seen
1623 * on the Internet today. For the moment, we'll sweep
1624 * this under the carpet.
1626 * The conservative default might not actually be a problem
1627 * if the only case this occurs is when sending an initial
1628 * SYN with options and data to a host we've never talked
1629 * to before. Then, they will reply with an MSS value which
1630 * will get recorded and the new parameters should get
1631 * recomputed. For Further Study.
1633 if (taop->tao_mssopt != 0 && taop->tao_mssopt < maxopd)
1634 maxopd = taop->tao_mssopt;
1638 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1639 sizeof(struct tcpiphdr));
1641 if (tp->t_maxopd <= maxopd)
1643 tp->t_maxopd = maxopd;
1646 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) ==
1647 (TF_REQ_TSTMP | TF_RCVD_TSTMP))
1648 mss -= TCPOLEN_TSTAMP_APPA;
1650 if ((tp->t_flags & (TF_REQ_CC | TF_RCVD_CC | TF_NOOPT)) ==
1651 (TF_REQ_CC | TF_RCVD_CC))
1652 mss -= TCPOLEN_CC_APPA;
1654 /* round down to multiple of MCLBYTES */
1655 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */
1657 mss &= ~(MCLBYTES - 1);
1660 mss = (mss / MCLBYTES) * MCLBYTES;
1663 if (so->so_snd.ssb_hiwat < mss)
1664 mss = so->so_snd.ssb_hiwat;
1668 tp->snd_nxt = tp->snd_una;
1670 tcpstat.tcps_mturesent++;
1674 * Look-up the routing entry to the peer of this inpcb. If no route
1675 * is found and it cannot be allocated the return NULL. This routine
1676 * is called by TCP routines that access the rmx structure and by tcp_mss
1677 * to get the interface MTU.
1680 tcp_rtlookup(struct in_conninfo *inc)
1682 struct route *ro = &inc->inc_route;
1684 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) {
1685 /* No route yet, so try to acquire one */
1686 if (inc->inc_faddr.s_addr != INADDR_ANY) {
1688 * unused portions of the structure MUST be zero'd
1689 * out because rtalloc() treats it as opaque data
1691 bzero(&ro->ro_dst, sizeof(struct sockaddr_in));
1692 ro->ro_dst.sa_family = AF_INET;
1693 ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
1694 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
1704 tcp_rtlookup6(struct in_conninfo *inc)
1706 struct route_in6 *ro6 = &inc->inc6_route;
1708 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) {
1709 /* No route yet, so try to acquire one */
1710 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
1712 * unused portions of the structure MUST be zero'd
1713 * out because rtalloc() treats it as opaque data
1715 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6));
1716 ro6->ro_dst.sin6_family = AF_INET6;
1717 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6);
1718 ro6->ro_dst.sin6_addr = inc->inc6_faddr;
1719 rtalloc((struct route *)ro6);
1722 return (ro6->ro_rt);
1727 /* compute ESP/AH header size for TCP, including outer IP header. */
1729 ipsec_hdrsiz_tcp(struct tcpcb *tp)
1737 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
1739 MGETHDR(m, MB_DONTWAIT, MT_DATA);
1744 if (inp->inp_vflag & INP_IPV6) {
1745 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1747 th = (struct tcphdr *)(ip6 + 1);
1748 m->m_pkthdr.len = m->m_len =
1749 sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1750 tcp_fillheaders(tp, ip6, th);
1751 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1755 ip = mtod(m, struct ip *);
1756 th = (struct tcphdr *)(ip + 1);
1757 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
1758 tcp_fillheaders(tp, ip, th);
1759 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1768 * Return a pointer to the cached information about the remote host.
1769 * The cached information is stored in the protocol specific part of
1770 * the route metrics.
1773 tcp_gettaocache(struct in_conninfo *inc)
1778 if (inc->inc_isipv6)
1779 rt = tcp_rtlookup6(inc);
1782 rt = tcp_rtlookup(inc);
1784 /* Make sure this is a host route and is up. */
1786 (rt->rt_flags & (RTF_UP | RTF_HOST)) != (RTF_UP | RTF_HOST))
1789 return (rmx_taop(rt->rt_rmx));
1793 * Clear all the TAO cache entries, called from tcp_init.
1796 * This routine is just an empty one, because we assume that the routing
1797 * routing tables are initialized at the same time when TCP, so there is
1798 * nothing in the cache left over.
1801 tcp_cleartaocache(void)
1806 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
1808 * This code attempts to calculate the bandwidth-delay product as a
1809 * means of determining the optimal window size to maximize bandwidth,
1810 * minimize RTT, and avoid the over-allocation of buffers on interfaces and
1811 * routers. This code also does a fairly good job keeping RTTs in check
1812 * across slow links like modems. We implement an algorithm which is very
1813 * similar (but not meant to be) TCP/Vegas. The code operates on the
1814 * transmitter side of a TCP connection and so only effects the transmit
1815 * side of the connection.
1817 * BACKGROUND: TCP makes no provision for the management of buffer space
1818 * at the end points or at the intermediate routers and switches. A TCP
1819 * stream, whether using NewReno or not, will eventually buffer as
1820 * many packets as it is able and the only reason this typically works is
1821 * due to the fairly small default buffers made available for a connection
1822 * (typicaly 16K or 32K). As machines use larger windows and/or window
1823 * scaling it is now fairly easy for even a single TCP connection to blow-out
1824 * all available buffer space not only on the local interface, but on
1825 * intermediate routers and switches as well. NewReno makes a misguided
1826 * attempt to 'solve' this problem by waiting for an actual failure to occur,
1827 * then backing off, then steadily increasing the window again until another
1828 * failure occurs, ad-infinitum. This results in terrible oscillation that
1829 * is only made worse as network loads increase and the idea of intentionally
1830 * blowing out network buffers is, frankly, a terrible way to manage network
1833 * It is far better to limit the transmit window prior to the failure
1834 * condition being achieved. There are two general ways to do this: First
1835 * you can 'scan' through different transmit window sizes and locate the
1836 * point where the RTT stops increasing, indicating that you have filled the
1837 * pipe, then scan backwards until you note that RTT stops decreasing, then
1838 * repeat ad-infinitum. This method works in principle but has severe
1839 * implementation issues due to RTT variances, timer granularity, and
1840 * instability in the algorithm which can lead to many false positives and
1841 * create oscillations as well as interact badly with other TCP streams
1842 * implementing the same algorithm.
1844 * The second method is to limit the window to the bandwidth delay product
1845 * of the link. This is the method we implement. RTT variances and our
1846 * own manipulation of the congestion window, bwnd, can potentially
1847 * destabilize the algorithm. For this reason we have to stabilize the
1848 * elements used to calculate the window. We do this by using the minimum
1849 * observed RTT, the long term average of the observed bandwidth, and
1850 * by adding two segments worth of slop. It isn't perfect but it is able
1851 * to react to changing conditions and gives us a very stable basis on
1852 * which to extend the algorithm.
1855 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq)
1863 * If inflight_enable is disabled in the middle of a tcp connection,
1864 * make sure snd_bwnd is effectively disabled.
1866 if (!tcp_inflight_enable) {
1867 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1868 tp->snd_bandwidth = 0;
1873 * Validate the delta time. If a connection is new or has been idle
1874 * a long time we have to reset the bandwidth calculator.
1877 delta_ticks = save_ticks - tp->t_bw_rtttime;
1878 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) {
1879 tp->t_bw_rtttime = ticks;
1880 tp->t_bw_rtseq = ack_seq;
1881 if (tp->snd_bandwidth == 0)
1882 tp->snd_bandwidth = tcp_inflight_min;
1885 if (delta_ticks == 0)
1889 * Sanity check, plus ignore pure window update acks.
1891 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0)
1895 * Figure out the bandwidth. Due to the tick granularity this
1896 * is a very rough number and it MUST be averaged over a fairly
1897 * long period of time. XXX we need to take into account a link
1898 * that is not using all available bandwidth, but for now our
1899 * slop will ramp us up if this case occurs and the bandwidth later
1902 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks;
1903 tp->t_bw_rtttime = save_ticks;
1904 tp->t_bw_rtseq = ack_seq;
1905 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4;
1907 tp->snd_bandwidth = bw;
1910 * Calculate the semi-static bandwidth delay product, plus two maximal
1911 * segments. The additional slop puts us squarely in the sweet
1912 * spot and also handles the bandwidth run-up case. Without the
1913 * slop we could be locking ourselves into a lower bandwidth.
1915 * Situations Handled:
1916 * (1) Prevents over-queueing of packets on LANs, especially on
1917 * high speed LANs, allowing larger TCP buffers to be
1918 * specified, and also does a good job preventing
1919 * over-queueing of packets over choke points like modems
1920 * (at least for the transmit side).
1922 * (2) Is able to handle changing network loads (bandwidth
1923 * drops so bwnd drops, bandwidth increases so bwnd
1926 * (3) Theoretically should stabilize in the face of multiple
1927 * connections implementing the same algorithm (this may need
1930 * (4) Stability value (defaults to 20 = 2 maximal packets) can
1931 * be adjusted with a sysctl but typically only needs to be on
1932 * very slow connections. A value no smaller then 5 should
1933 * be used, but only reduce this default if you have no other
1937 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2)
1938 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) +
1939 tcp_inflight_stab * (int)tp->t_maxseg / 10;
1942 if (tcp_inflight_debug > 0) {
1944 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) {
1946 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n",
1947 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd);
1950 if ((long)bwnd < tcp_inflight_min)
1951 bwnd = tcp_inflight_min;
1952 if (bwnd > tcp_inflight_max)
1953 bwnd = tcp_inflight_max;
1954 if ((long)bwnd < tp->t_maxseg * 2)
1955 bwnd = tp->t_maxseg * 2;
1956 tp->snd_bwnd = bwnd;