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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21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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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 1.63 2008/11/11 10:46:58 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_timer2.h>
120 #include <netinet/tcp_var.h>
121 #include <netinet6/tcp6_var.h>
122 #include <netinet/tcpip.h>
124 #include <netinet/tcp_debug.h>
126 #include <netinet6/ip6protosw.h>
129 #include <netinet6/ipsec.h>
131 #include <netinet6/ipsec6.h>
136 #include <netproto/ipsec/ipsec.h>
138 #include <netproto/ipsec/ipsec6.h>
144 #include <sys/msgport2.h>
145 #include <machine/smp.h>
147 #include <net/netmsg2.h>
149 #if !defined(KTR_TCP)
150 #define KTR_TCP KTR_ALL
152 KTR_INFO_MASTER(tcp);
153 KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0);
154 KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0);
155 KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0);
156 #define logtcp(name) KTR_LOG(tcp_ ## name)
158 struct inpcbinfo tcbinfo[MAXCPU];
159 struct tcpcbackqhead tcpcbackq[MAXCPU];
161 int tcp_mpsafe_proto = 0;
162 TUNABLE_INT("net.inet.tcp.mpsafe_proto", &tcp_mpsafe_proto);
164 static int tcp_mpsafe_thread = 0;
165 TUNABLE_INT("net.inet.tcp.mpsafe_thread", &tcp_mpsafe_thread);
166 SYSCTL_INT(_net_inet_tcp, OID_AUTO, mpsafe_thread, CTLFLAG_RW,
167 &tcp_mpsafe_thread, 0,
168 "0:BGL, 1:Adaptive BGL, 2:No BGL(experimental)");
170 int tcp_mssdflt = TCP_MSS;
171 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW,
172 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size");
175 int tcp_v6mssdflt = TCP6_MSS;
176 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW,
177 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6");
181 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
182 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW,
183 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time");
186 int tcp_do_rfc1323 = 1;
187 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
188 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions");
190 int tcp_do_rfc1644 = 0;
191 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW,
192 &tcp_do_rfc1644, 0, "Enable rfc1644 (TTCP) extensions");
194 static int tcp_tcbhashsize = 0;
195 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD,
196 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable");
198 static int do_tcpdrain = 1;
199 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
200 "Enable tcp_drain routine for extra help when low on mbufs");
203 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
204 &tcbinfo[0].ipi_count, 0, "Number of active PCBs");
206 static int icmp_may_rst = 1;
207 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0,
208 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
210 static int tcp_isn_reseed_interval = 0;
211 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
212 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret");
215 * TCP bandwidth limiting sysctls. Note that the default lower bound of
216 * 1024 exists only for debugging. A good production default would be
217 * something like 6100.
219 static int tcp_inflight_enable = 0;
220 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW,
221 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting");
223 static int tcp_inflight_debug = 0;
224 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW,
225 &tcp_inflight_debug, 0, "Debug TCP inflight calculations");
227 static int tcp_inflight_min = 6144;
228 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW,
229 &tcp_inflight_min, 0, "Lower bound for TCP inflight window");
231 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT;
232 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW,
233 &tcp_inflight_max, 0, "Upper bound for TCP inflight window");
235 static int tcp_inflight_stab = 20;
236 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW,
237 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 2 packets)");
239 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives");
240 static struct malloc_pipe tcptemp_mpipe;
242 static void tcp_willblock(int);
243 static void tcp_cleartaocache (void);
244 static void tcp_notify (struct inpcb *, int);
246 struct tcp_stats tcpstats_percpu[MAXCPU];
249 sysctl_tcpstats(SYSCTL_HANDLER_ARGS)
253 for (cpu = 0; cpu < ncpus; ++cpu) {
254 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu],
255 sizeof(struct tcp_stats))))
257 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu],
258 sizeof(struct tcp_stats))))
264 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW),
265 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics");
267 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW,
268 &tcpstat, tcp_stats, "TCP statistics");
272 * Target size of TCP PCB hash tables. Must be a power of two.
274 * Note that this can be overridden by the kernel environment
275 * variable net.inet.tcp.tcbhashsize
278 #define TCBHASHSIZE 512
282 * This is the actual shape of what we allocate using the zone
283 * allocator. Doing it this way allows us to protect both structures
284 * using the same generation count, and also eliminates the overhead
285 * of allocating tcpcbs separately. By hiding the structure here,
286 * we avoid changing most of the rest of the code (although it needs
287 * to be changed, eventually, for greater efficiency).
290 #define ALIGNM1 (ALIGNMENT - 1)
294 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1];
297 struct tcp_callout inp_tp_rexmt;
298 struct tcp_callout inp_tp_persist;
299 struct tcp_callout inp_tp_keep;
300 struct tcp_callout inp_tp_2msl;
301 struct tcp_callout inp_tp_delack;
302 struct netmsg_tcp_timer inp_tp_timermsg;
313 struct inpcbporthead *porthashbase;
315 struct vm_zone *ipi_zone;
316 int hashsize = TCBHASHSIZE;
320 * note: tcptemp is used for keepalives, and it is ok for an
321 * allocation to fail so do not specify MPF_INT.
323 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp),
329 tcp_delacktime = TCPTV_DELACK;
330 tcp_keepinit = TCPTV_KEEP_INIT;
331 tcp_keepidle = TCPTV_KEEP_IDLE;
332 tcp_keepintvl = TCPTV_KEEPINTVL;
333 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
335 tcp_rexmit_min = TCPTV_MIN;
336 tcp_rexmit_slop = TCPTV_CPU_VAR;
338 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
339 if (!powerof2(hashsize)) {
340 kprintf("WARNING: TCB hash size not a power of 2\n");
341 hashsize = 512; /* safe default */
343 tcp_tcbhashsize = hashsize;
344 porthashbase = hashinit(hashsize, M_PCB, &porthashmask);
345 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets,
348 for (cpu = 0; cpu < ncpus2; cpu++) {
349 in_pcbinfo_init(&tcbinfo[cpu]);
350 tcbinfo[cpu].cpu = cpu;
351 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB,
352 &tcbinfo[cpu].hashmask);
353 tcbinfo[cpu].porthashbase = porthashbase;
354 tcbinfo[cpu].porthashmask = porthashmask;
355 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB,
356 &tcbinfo[cpu].wildcardhashmask);
357 tcbinfo[cpu].ipi_zone = ipi_zone;
358 TAILQ_INIT(&tcpcbackq[cpu]);
361 tcp_reass_maxseg = nmbclusters / 16;
362 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg);
365 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
367 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
369 if (max_protohdr < TCP_MINPROTOHDR)
370 max_protohdr = TCP_MINPROTOHDR;
371 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
373 #undef TCP_MINPROTOHDR
376 * Initialize TCP statistics counters for each CPU.
379 for (cpu = 0; cpu < ncpus; ++cpu) {
380 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats));
383 bzero(&tcpstat, sizeof(struct tcp_stats));
391 tcpmsg_service_loop(void *dummy)
397 * Thread was started with TDF_MPSAFE
401 while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) {
404 mplocked = netmsg_service(msg, tcp_mpsafe_thread,
406 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL);
409 tcp_willblock(mplocked);
415 tcp_willblock(int mplocked)
418 int cpu = mycpu->gd_cpuid;
421 if (!mplocked && !tcp_mpsafe_proto) {
422 if (TAILQ_EMPTY(&tcpcbackq[cpu]))
430 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) {
431 KKASSERT(tp->t_flags & TF_ONOUTPUTQ);
432 tp->t_flags &= ~TF_ONOUTPUTQ;
433 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq);
443 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
444 * tcp_template used to store this data in mbufs, but we now recopy it out
445 * of the tcpcb each time to conserve mbufs.
448 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr)
450 struct inpcb *inp = tp->t_inpcb;
451 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr;
454 if (inp->inp_vflag & INP_IPV6) {
457 ip6 = (struct ip6_hdr *)ip_ptr;
458 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
459 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK);
460 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
461 (IPV6_VERSION & IPV6_VERSION_MASK);
462 ip6->ip6_nxt = IPPROTO_TCP;
463 ip6->ip6_plen = sizeof(struct tcphdr);
464 ip6->ip6_src = inp->in6p_laddr;
465 ip6->ip6_dst = inp->in6p_faddr;
470 struct ip *ip = (struct ip *) ip_ptr;
472 ip->ip_vhl = IP_VHL_BORING;
479 ip->ip_p = IPPROTO_TCP;
480 ip->ip_src = inp->inp_laddr;
481 ip->ip_dst = inp->inp_faddr;
482 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr,
484 htons(sizeof(struct tcphdr) + IPPROTO_TCP));
487 tcp_hdr->th_sport = inp->inp_lport;
488 tcp_hdr->th_dport = inp->inp_fport;
493 tcp_hdr->th_flags = 0;
499 * Create template to be used to send tcp packets on a connection.
500 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
501 * use for this function is in keepalives, which use tcp_respond.
504 tcp_maketemplate(struct tcpcb *tp)
508 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL)
510 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t);
515 tcp_freetemplate(struct tcptemp *tmp)
517 mpipe_free(&tcptemp_mpipe, tmp);
521 * Send a single message to the TCP at address specified by
522 * the given TCP/IP header. If m == NULL, then we make a copy
523 * of the tcpiphdr at ti and send directly to the addressed host.
524 * This is used to force keep alive messages out using the TCP
525 * template for a connection. If flags are given then we send
526 * a message back to the TCP which originated the * segment ti,
527 * and discard the mbuf containing it and any other attached mbufs.
529 * In any case the ack and sequence number of the transmitted
530 * segment are as specified by the parameters.
532 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
535 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
536 tcp_seq ack, tcp_seq seq, int flags)
540 struct route *ro = NULL;
542 struct ip *ip = ipgen;
545 struct route_in6 *ro6 = NULL;
546 struct route_in6 sro6;
547 struct ip6_hdr *ip6 = ipgen;
548 boolean_t use_tmpro = TRUE;
550 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6);
552 const boolean_t isipv6 = FALSE;
556 if (!(flags & TH_RST)) {
557 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv);
558 if (win > (long)TCP_MAXWIN << tp->rcv_scale)
559 win = (long)TCP_MAXWIN << tp->rcv_scale;
562 * Don't use the route cache of a listen socket,
563 * it is not MPSAFE; use temporary route cache.
565 if (tp->t_state != TCPS_LISTEN) {
567 ro6 = &tp->t_inpcb->in6p_route;
569 ro = &tp->t_inpcb->inp_route;
576 bzero(ro6, sizeof *ro6);
579 bzero(ro, sizeof *ro);
583 m = m_gethdr(MB_DONTWAIT, MT_HEADER);
587 m->m_data += max_linkhdr;
589 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr));
590 ip6 = mtod(m, struct ip6_hdr *);
591 nth = (struct tcphdr *)(ip6 + 1);
593 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
594 ip = mtod(m, struct ip *);
595 nth = (struct tcphdr *)(ip + 1);
597 bcopy(th, nth, sizeof(struct tcphdr));
602 m->m_data = (caddr_t)ipgen;
603 /* m_len is set later */
605 #define xchg(a, b, type) { type t; t = a; a = b; b = t; }
607 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
608 nth = (struct tcphdr *)(ip6 + 1);
610 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long);
611 nth = (struct tcphdr *)(ip + 1);
615 * this is usually a case when an extension header
616 * exists between the IPv6 header and the
619 nth->th_sport = th->th_sport;
620 nth->th_dport = th->th_dport;
622 xchg(nth->th_dport, nth->th_sport, n_short);
627 ip6->ip6_vfc = IPV6_VERSION;
628 ip6->ip6_nxt = IPPROTO_TCP;
629 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen));
630 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
632 tlen += sizeof(struct tcpiphdr);
634 ip->ip_ttl = ip_defttl;
637 m->m_pkthdr.len = tlen;
638 m->m_pkthdr.rcvif = (struct ifnet *) NULL;
639 nth->th_seq = htonl(seq);
640 nth->th_ack = htonl(ack);
642 nth->th_off = sizeof(struct tcphdr) >> 2;
643 nth->th_flags = flags;
645 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
647 nth->th_win = htons((u_short)win);
651 nth->th_sum = in6_cksum(m, IPPROTO_TCP,
652 sizeof(struct ip6_hdr),
653 tlen - sizeof(struct ip6_hdr));
654 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL,
655 (ro6 && ro6->ro_rt) ?
656 ro6->ro_rt->rt_ifp : NULL);
658 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
659 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
660 m->m_pkthdr.csum_flags = CSUM_TCP;
661 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
664 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
665 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
668 ip6_output(m, NULL, ro6, ipflags, NULL, NULL,
669 tp ? tp->t_inpcb : NULL);
670 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) {
675 ipflags |= IP_DEBUGROUTE;
676 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL);
677 if ((ro == &sro) && (ro->ro_rt != NULL)) {
685 * Create a new TCP control block, making an
686 * empty reassembly queue and hooking it to the argument
687 * protocol control block. The `inp' parameter must have
688 * come from the zone allocator set up in tcp_init().
691 tcp_newtcpcb(struct inpcb *inp)
696 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0);
698 const boolean_t isipv6 = FALSE;
701 it = (struct inp_tp *)inp;
703 bzero(tp, sizeof(struct tcpcb));
704 LIST_INIT(&tp->t_segq);
705 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt;
707 /* Set up our timeouts. */
708 tp->tt_rexmt = &it->inp_tp_rexmt;
709 tp->tt_persist = &it->inp_tp_persist;
710 tp->tt_keep = &it->inp_tp_keep;
711 tp->tt_2msl = &it->inp_tp_2msl;
712 tp->tt_delack = &it->inp_tp_delack;
715 tp->tt_msg = &it->inp_tp_timermsg;
717 /* Don't mess with IPv6; always create timer message */
718 tcp_create_timermsg(tp);
721 * Zero out timer message. We don't create it here,
722 * since the current CPU may not be the owner of this
725 bzero(tp->tt_msg, sizeof(*tp->tt_msg));
729 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP);
731 tp->t_flags |= TF_REQ_CC;
732 tp->t_inpcb = inp; /* XXX */
733 tp->t_state = TCPS_CLOSED;
735 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
736 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
737 * reasonable initial retransmit time.
739 tp->t_srtt = TCPTV_SRTTBASE;
741 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
742 tp->t_rttmin = tcp_rexmit_min;
743 tp->t_rxtcur = TCPTV_RTOBASE;
744 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
745 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
746 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
747 tp->t_rcvtime = ticks;
749 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
750 * because the socket may be bound to an IPv6 wildcard address,
751 * which may match an IPv4-mapped IPv6 address.
753 inp->inp_ip_ttl = ip_defttl;
755 tcp_sack_tcpcb_init(tp);
756 return (tp); /* XXX */
760 * Drop a TCP connection, reporting the specified error.
761 * If connection is synchronized, then send a RST to peer.
764 tcp_drop(struct tcpcb *tp, int error)
766 struct socket *so = tp->t_inpcb->inp_socket;
768 if (TCPS_HAVERCVDSYN(tp->t_state)) {
769 tp->t_state = TCPS_CLOSED;
771 tcpstat.tcps_drops++;
773 tcpstat.tcps_conndrops++;
774 if (error == ETIMEDOUT && tp->t_softerror)
775 error = tp->t_softerror;
776 so->so_error = error;
777 return (tcp_close(tp));
782 struct netmsg_remwildcard {
783 struct netmsg nm_netmsg;
784 struct inpcb *nm_inp;
785 struct inpcbinfo *nm_pcbinfo;
794 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the
795 * inp can be detached. We do this by cycling through the cpus, ending up
796 * on the cpu controlling the inp last and then doing the disconnect.
799 in_pcbremwildcardhash_handler(struct netmsg *msg0)
801 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0;
804 cpu = msg->nm_pcbinfo->cpu;
806 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) {
807 /* note: detach removes any wildcard hash entry */
810 in6_pcbdetach(msg->nm_inp);
813 in_pcbdetach(msg->nm_inp);
814 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0);
816 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo);
817 cpu = (cpu + 1) % ncpus2;
818 msg->nm_pcbinfo = &tcbinfo[cpu];
819 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg);
826 * Close a TCP control block:
827 * discard all space held by the tcp
828 * discard internet protocol block
829 * wake up any sleepers
832 tcp_close(struct tcpcb *tp)
835 struct inpcb *inp = tp->t_inpcb;
836 struct socket *so = inp->inp_socket;
838 boolean_t dosavessthresh;
843 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0);
844 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0);
846 const boolean_t isipv6 = FALSE;
850 * The tp is not instantly destroyed in the wildcard case. Setting
851 * the state to TCPS_TERMINATING will prevent the TCP stack from
852 * messing with it, though it should be noted that this change may
853 * not take effect on other cpus until we have chained the wildcard
856 * XXX we currently depend on the BGL to synchronize the tp->t_state
857 * update and prevent other tcp protocol threads from accepting new
858 * connections on the listen socket we might be trying to close down.
860 KKASSERT(tp->t_state != TCPS_TERMINATING);
861 tp->t_state = TCPS_TERMINATING;
864 * Make sure that all of our timers are stopped before we
865 * delete the PCB. For listen TCP socket (tp->tt_msg == NULL),
866 * timers are never used.
868 if (tp->tt_msg != NULL) {
869 tcp_callout_stop(tp, tp->tt_rexmt);
870 tcp_callout_stop(tp, tp->tt_persist);
871 tcp_callout_stop(tp, tp->tt_keep);
872 tcp_callout_stop(tp, tp->tt_2msl);
873 tcp_callout_stop(tp, tp->tt_delack);
876 if (tp->t_flags & TF_ONOUTPUTQ) {
877 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid);
878 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq);
879 tp->t_flags &= ~TF_ONOUTPUTQ;
883 * If we got enough samples through the srtt filter,
884 * save the rtt and rttvar in the routing entry.
885 * 'Enough' is arbitrarily defined as the 16 samples.
886 * 16 samples is enough for the srtt filter to converge
887 * to within 5% of the correct value; fewer samples and
888 * we could save a very bogus rtt.
890 * Don't update the default route's characteristics and don't
891 * update anything that the user "locked".
893 if (tp->t_rttupdated >= 16) {
897 struct sockaddr_in6 *sin6;
899 if ((rt = inp->in6p_route.ro_rt) == NULL)
901 sin6 = (struct sockaddr_in6 *)rt_key(rt);
902 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr))
905 if ((rt = inp->inp_route.ro_rt) == NULL ||
906 ((struct sockaddr_in *)rt_key(rt))->
907 sin_addr.s_addr == INADDR_ANY)
910 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) {
911 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE));
912 if (rt->rt_rmx.rmx_rtt && i)
914 * filter this update to half the old & half
915 * the new values, converting scale.
916 * See route.h and tcp_var.h for a
917 * description of the scaling constants.
920 (rt->rt_rmx.rmx_rtt + i) / 2;
922 rt->rt_rmx.rmx_rtt = i;
923 tcpstat.tcps_cachedrtt++;
925 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) {
927 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE));
928 if (rt->rt_rmx.rmx_rttvar && i)
929 rt->rt_rmx.rmx_rttvar =
930 (rt->rt_rmx.rmx_rttvar + i) / 2;
932 rt->rt_rmx.rmx_rttvar = i;
933 tcpstat.tcps_cachedrttvar++;
936 * The old comment here said:
937 * update the pipelimit (ssthresh) if it has been updated
938 * already or if a pipesize was specified & the threshhold
939 * got below half the pipesize. I.e., wait for bad news
940 * before we start updating, then update on both good
943 * But we want to save the ssthresh even if no pipesize is
944 * specified explicitly in the route, because such
945 * connections still have an implicit pipesize specified
946 * by the global tcp_sendspace. In the absence of a reliable
947 * way to calculate the pipesize, it will have to do.
949 i = tp->snd_ssthresh;
950 if (rt->rt_rmx.rmx_sendpipe != 0)
951 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2);
953 dosavessthresh = (i < so->so_snd.ssb_hiwat/2);
954 if (dosavessthresh ||
955 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) &&
956 (rt->rt_rmx.rmx_ssthresh != 0))) {
958 * convert the limit from user data bytes to
959 * packets then to packet data bytes.
961 i = (i + tp->t_maxseg / 2) / tp->t_maxseg;
966 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
967 sizeof(struct tcpiphdr));
968 if (rt->rt_rmx.rmx_ssthresh)
969 rt->rt_rmx.rmx_ssthresh =
970 (rt->rt_rmx.rmx_ssthresh + i) / 2;
972 rt->rt_rmx.rmx_ssthresh = i;
973 tcpstat.tcps_cachedssthresh++;
978 /* free the reassembly queue, if any */
979 while((q = LIST_FIRST(&tp->t_segq)) != NULL) {
980 LIST_REMOVE(q, tqe_q);
985 /* throw away SACK blocks in scoreboard*/
987 tcp_sack_cleanup(&tp->scb);
989 inp->inp_ppcb = NULL;
990 soisdisconnected(so);
992 tcp_destroy_timermsg(tp);
995 * Discard the inp. In the SMP case a wildcard inp's hash (created
996 * by a listen socket or an INADDR_ANY udp socket) is replicated
997 * for each protocol thread and must be removed in the context of
998 * that thread. This is accomplished by chaining the message
1001 * If the inp is not wildcarded we simply detach, which will remove
1002 * the any hashes still present for this inp.
1005 if (inp->inp_flags & INP_WILDCARD_MP) {
1006 struct netmsg_remwildcard *msg;
1008 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2;
1009 msg = kmalloc(sizeof(struct netmsg_remwildcard),
1010 M_LWKTMSG, M_INTWAIT);
1011 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0,
1012 in_pcbremwildcardhash_handler);
1014 msg->nm_isinet6 = isafinet6;
1017 msg->nm_pcbinfo = &tcbinfo[cpu];
1018 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg);
1022 /* note: detach removes any wildcard hash entry */
1030 tcpstat.tcps_closed++;
1034 static __inline void
1035 tcp_drain_oncpu(struct inpcbhead *head)
1039 struct tseg_qent *te;
1041 LIST_FOREACH(inpb, head, inp_list) {
1042 if (inpb->inp_flags & INP_PLACEMARKER)
1044 if ((tcpb = intotcpcb(inpb))) {
1045 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) {
1046 LIST_REMOVE(te, tqe_q);
1056 struct netmsg_tcp_drain {
1057 struct netmsg nm_netmsg;
1058 struct inpcbhead *nm_head;
1062 tcp_drain_handler(netmsg_t netmsg)
1064 struct netmsg_tcp_drain *nm = (void *)netmsg;
1066 tcp_drain_oncpu(nm->nm_head);
1067 lwkt_replymsg(&nm->nm_netmsg.nm_lmsg, 0);
1082 * Walk the tcpbs, if existing, and flush the reassembly queue,
1083 * if there is one...
1084 * XXX: The "Net/3" implementation doesn't imply that the TCP
1085 * reassembly queue should be flushed, but in a situation
1086 * where we're really low on mbufs, this is potentially
1090 for (cpu = 0; cpu < ncpus2; cpu++) {
1091 struct netmsg_tcp_drain *msg;
1093 if (cpu == mycpu->gd_cpuid) {
1094 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead);
1096 msg = kmalloc(sizeof(struct netmsg_tcp_drain),
1097 M_LWKTMSG, M_NOWAIT);
1100 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0,
1102 msg->nm_head = &tcbinfo[cpu].pcblisthead;
1103 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg);
1107 tcp_drain_oncpu(&tcbinfo[0].pcblisthead);
1112 * Notify a tcp user of an asynchronous error;
1113 * store error as soft error, but wake up user
1114 * (for now, won't do anything until can select for soft error).
1116 * Do not wake up user since there currently is no mechanism for
1117 * reporting soft errors (yet - a kqueue filter may be added).
1120 tcp_notify(struct inpcb *inp, int error)
1122 struct tcpcb *tp = intotcpcb(inp);
1125 * Ignore some errors if we are hooked up.
1126 * If connection hasn't completed, has retransmitted several times,
1127 * and receives a second error, give up now. This is better
1128 * than waiting a long time to establish a connection that
1129 * can never complete.
1131 if (tp->t_state == TCPS_ESTABLISHED &&
1132 (error == EHOSTUNREACH || error == ENETUNREACH ||
1133 error == EHOSTDOWN)) {
1135 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
1137 tcp_drop(tp, error);
1139 tp->t_softerror = error;
1141 wakeup(&so->so_timeo);
1148 tcp_pcblist(SYSCTL_HANDLER_ARGS)
1151 struct inpcb *marker;
1161 * The process of preparing the TCB list is too time-consuming and
1162 * resource-intensive to repeat twice on every request.
1164 if (req->oldptr == NULL) {
1165 for (ccpu = 0; ccpu < ncpus; ++ccpu) {
1166 gd = globaldata_find(ccpu);
1167 n += tcbinfo[gd->gd_cpuid].ipi_count;
1169 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb);
1173 if (req->newptr != NULL)
1176 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO);
1177 marker->inp_flags |= INP_PLACEMARKER;
1180 * OK, now we're committed to doing something. Run the inpcb list
1181 * for each cpu in the system and construct the output. Use a
1182 * list placemarker to deal with list changes occuring during
1183 * copyout blockages (but otherwise depend on being on the correct
1184 * cpu to avoid races).
1186 origcpu = mycpu->gd_cpuid;
1187 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) {
1193 cpu_id = (origcpu + ccpu) % ncpus;
1194 if ((smp_active_mask & (1 << cpu_id)) == 0)
1196 rgd = globaldata_find(cpu_id);
1197 lwkt_setcpu_self(rgd);
1199 gencnt = tcbinfo[cpu_id].ipi_gencnt;
1200 n = tcbinfo[cpu_id].ipi_count;
1202 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list);
1204 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) {
1206 * process a snapshot of pcbs, ignoring placemarkers
1207 * and using our own to allow SYSCTL_OUT to block.
1209 LIST_REMOVE(marker, inp_list);
1210 LIST_INSERT_AFTER(inp, marker, inp_list);
1212 if (inp->inp_flags & INP_PLACEMARKER)
1214 if (inp->inp_gencnt > gencnt)
1216 if (prison_xinpcb(req->td, inp))
1219 xt.xt_len = sizeof xt;
1220 bcopy(inp, &xt.xt_inp, sizeof *inp);
1221 inp_ppcb = inp->inp_ppcb;
1222 if (inp_ppcb != NULL)
1223 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
1225 bzero(&xt.xt_tp, sizeof xt.xt_tp);
1226 if (inp->inp_socket)
1227 sotoxsocket(inp->inp_socket, &xt.xt_socket);
1228 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0)
1232 LIST_REMOVE(marker, inp_list);
1233 if (error == 0 && i < n) {
1234 bzero(&xt, sizeof xt);
1235 xt.xt_len = sizeof xt;
1237 error = SYSCTL_OUT(req, &xt, sizeof xt);
1246 * Make sure we are on the same cpu we were on originally, since
1247 * higher level callers expect this. Also don't pollute caches with
1248 * migrated userland data by (eventually) returning to userland
1249 * on a different cpu.
1251 lwkt_setcpu_self(globaldata_find(origcpu));
1252 kfree(marker, M_TEMP);
1256 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
1257 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
1260 tcp_getcred(SYSCTL_HANDLER_ARGS)
1262 struct sockaddr_in addrs[2];
1267 error = suser(req->td);
1270 error = SYSCTL_IN(req, addrs, sizeof addrs);
1274 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port,
1275 addrs[0].sin_addr.s_addr, addrs[0].sin_port);
1276 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr,
1277 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
1278 if (inp == NULL || inp->inp_socket == NULL) {
1282 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
1288 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW),
1289 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection");
1293 tcp6_getcred(SYSCTL_HANDLER_ARGS)
1295 struct sockaddr_in6 addrs[2];
1298 boolean_t mapped = FALSE;
1300 error = suser(req->td);
1303 error = SYSCTL_IN(req, addrs, sizeof addrs);
1306 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
1307 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
1314 inp = in_pcblookup_hash(&tcbinfo[0],
1315 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
1317 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
1321 inp = in6_pcblookup_hash(&tcbinfo[0],
1322 &addrs[1].sin6_addr, addrs[1].sin6_port,
1323 &addrs[0].sin6_addr, addrs[0].sin6_port,
1326 if (inp == NULL || inp->inp_socket == NULL) {
1330 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
1336 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW),
1338 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection");
1341 struct netmsg_tcp_notify {
1342 struct netmsg nm_nmsg;
1343 void (*nm_notify)(struct inpcb *, int);
1344 struct in_addr nm_faddr;
1349 tcp_notifyall_oncpu(struct netmsg *netmsg)
1351 struct netmsg_tcp_notify *nmsg = (struct netmsg_tcp_notify *)netmsg;
1354 in_pcbnotifyall(&tcbinfo[mycpuid].pcblisthead, nmsg->nm_faddr,
1355 nmsg->nm_arg, nmsg->nm_notify);
1357 nextcpu = mycpuid + 1;
1358 if (nextcpu < ncpus2)
1359 lwkt_forwardmsg(tcp_cport(nextcpu), &netmsg->nm_lmsg);
1361 lwkt_replymsg(&netmsg->nm_lmsg, 0);
1365 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
1367 struct ip *ip = vip;
1369 struct in_addr faddr;
1372 void (*notify)(struct inpcb *, int) = tcp_notify;
1376 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) {
1380 faddr = ((struct sockaddr_in *)sa)->sin_addr;
1381 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
1384 arg = inetctlerrmap[cmd];
1385 if (cmd == PRC_QUENCH) {
1386 notify = tcp_quench;
1387 } else if (icmp_may_rst &&
1388 (cmd == PRC_UNREACH_ADMIN_PROHIB ||
1389 cmd == PRC_UNREACH_PORT ||
1390 cmd == PRC_TIMXCEED_INTRANS) &&
1392 notify = tcp_drop_syn_sent;
1393 } else if (cmd == PRC_MSGSIZE) {
1394 struct icmp *icmp = (struct icmp *)
1395 ((caddr_t)ip - offsetof(struct icmp, icmp_ip));
1397 arg = ntohs(icmp->icmp_nextmtu);
1398 notify = tcp_mtudisc;
1399 } else if (PRC_IS_REDIRECT(cmd)) {
1401 notify = in_rtchange;
1402 } else if (cmd == PRC_HOSTDEAD) {
1408 th = (struct tcphdr *)((caddr_t)ip +
1409 (IP_VHL_HL(ip->ip_vhl) << 2));
1410 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport,
1411 ip->ip_src.s_addr, th->th_sport);
1412 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport,
1413 ip->ip_src, th->th_sport, 0, NULL);
1414 if ((inp != NULL) && (inp->inp_socket != NULL)) {
1415 icmpseq = htonl(th->th_seq);
1416 tp = intotcpcb(inp);
1417 if (SEQ_GEQ(icmpseq, tp->snd_una) &&
1418 SEQ_LT(icmpseq, tp->snd_max))
1419 (*notify)(inp, arg);
1421 struct in_conninfo inc;
1423 inc.inc_fport = th->th_dport;
1424 inc.inc_lport = th->th_sport;
1425 inc.inc_faddr = faddr;
1426 inc.inc_laddr = ip->ip_src;
1430 syncache_unreach(&inc, th);
1434 struct netmsg_tcp_notify nmsg;
1436 KKASSERT(&curthread->td_msgport == cpu_portfn(0));
1437 netmsg_init(&nmsg.nm_nmsg, &curthread->td_msgport, 0,
1438 tcp_notifyall_oncpu);
1439 nmsg.nm_faddr = faddr;
1441 nmsg.nm_notify = notify;
1443 lwkt_domsg(tcp_cport(0), &nmsg.nm_nmsg.nm_lmsg, 0);
1449 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
1452 void (*notify) (struct inpcb *, int) = tcp_notify;
1453 struct ip6_hdr *ip6;
1455 struct ip6ctlparam *ip6cp = NULL;
1456 const struct sockaddr_in6 *sa6_src = NULL;
1458 struct tcp_portonly {
1464 if (sa->sa_family != AF_INET6 ||
1465 sa->sa_len != sizeof(struct sockaddr_in6))
1469 if (cmd == PRC_QUENCH)
1470 notify = tcp_quench;
1471 else if (cmd == PRC_MSGSIZE) {
1472 struct ip6ctlparam *ip6cp = d;
1473 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
1475 arg = ntohl(icmp6->icmp6_mtu);
1476 notify = tcp_mtudisc;
1477 } else if (!PRC_IS_REDIRECT(cmd) &&
1478 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) {
1482 /* if the parameter is from icmp6, decode it. */
1484 ip6cp = (struct ip6ctlparam *)d;
1486 ip6 = ip6cp->ip6c_ip6;
1487 off = ip6cp->ip6c_off;
1488 sa6_src = ip6cp->ip6c_src;
1492 off = 0; /* fool gcc */
1497 struct in_conninfo inc;
1499 * XXX: We assume that when IPV6 is non NULL,
1500 * M and OFF are valid.
1503 /* check if we can safely examine src and dst ports */
1504 if (m->m_pkthdr.len < off + sizeof *thp)
1507 bzero(&th, sizeof th);
1508 m_copydata(m, off, sizeof *thp, (caddr_t)&th);
1510 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport,
1511 (struct sockaddr *)ip6cp->ip6c_src,
1512 th.th_sport, cmd, arg, notify);
1514 inc.inc_fport = th.th_dport;
1515 inc.inc_lport = th.th_sport;
1516 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
1517 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
1519 syncache_unreach(&inc, &th);
1521 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0,
1522 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify);
1527 * Following is where TCP initial sequence number generation occurs.
1529 * There are two places where we must use initial sequence numbers:
1530 * 1. In SYN-ACK packets.
1531 * 2. In SYN packets.
1533 * All ISNs for SYN-ACK packets are generated by the syncache. See
1534 * tcp_syncache.c for details.
1536 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
1537 * depends on this property. In addition, these ISNs should be
1538 * unguessable so as to prevent connection hijacking. To satisfy
1539 * the requirements of this situation, the algorithm outlined in
1540 * RFC 1948 is used to generate sequence numbers.
1542 * Implementation details:
1544 * Time is based off the system timer, and is corrected so that it
1545 * increases by one megabyte per second. This allows for proper
1546 * recycling on high speed LANs while still leaving over an hour
1549 * net.inet.tcp.isn_reseed_interval controls the number of seconds
1550 * between seeding of isn_secret. This is normally set to zero,
1551 * as reseeding should not be necessary.
1555 #define ISN_BYTES_PER_SECOND 1048576
1557 u_char isn_secret[32];
1558 int isn_last_reseed;
1562 tcp_new_isn(struct tcpcb *tp)
1564 u_int32_t md5_buffer[4];
1567 /* Seed if this is the first use, reseed if requested. */
1568 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) &&
1569 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz)
1571 read_random_unlimited(&isn_secret, sizeof isn_secret);
1572 isn_last_reseed = ticks;
1575 /* Compute the md5 hash and return the ISN. */
1577 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short));
1578 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short));
1580 if (tp->t_inpcb->inp_vflag & INP_IPV6) {
1581 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
1582 sizeof(struct in6_addr));
1583 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
1584 sizeof(struct in6_addr));
1588 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
1589 sizeof(struct in_addr));
1590 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
1591 sizeof(struct in_addr));
1593 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret));
1594 MD5Final((u_char *) &md5_buffer, &isn_ctx);
1595 new_isn = (tcp_seq) md5_buffer[0];
1596 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz);
1601 * When a source quench is received, close congestion window
1602 * to one segment. We will gradually open it again as we proceed.
1605 tcp_quench(struct inpcb *inp, int error)
1607 struct tcpcb *tp = intotcpcb(inp);
1610 tp->snd_cwnd = tp->t_maxseg;
1616 * When a specific ICMP unreachable message is received and the
1617 * connection state is SYN-SENT, drop the connection. This behavior
1618 * is controlled by the icmp_may_rst sysctl.
1621 tcp_drop_syn_sent(struct inpcb *inp, int error)
1623 struct tcpcb *tp = intotcpcb(inp);
1625 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT))
1626 tcp_drop(tp, error);
1630 * When a `need fragmentation' ICMP is received, update our idea of the MSS
1631 * based on the new value in the route. Also nudge TCP to send something,
1632 * since we know the packet we just sent was dropped.
1633 * This duplicates some code in the tcp_mss() function in tcp_input.c.
1636 tcp_mtudisc(struct inpcb *inp, int mtu)
1638 struct tcpcb *tp = intotcpcb(inp);
1640 struct socket *so = inp->inp_socket;
1643 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0);
1645 const boolean_t isipv6 = FALSE;
1652 * If no MTU is provided in the ICMP message, use the
1653 * next lower likely value, as specified in RFC 1191.
1658 oldmtu = tp->t_maxopd +
1660 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1661 sizeof(struct tcpiphdr));
1662 mtu = ip_next_mtu(oldmtu, 0);
1666 rt = tcp_rtlookup6(&inp->inp_inc);
1668 rt = tcp_rtlookup(&inp->inp_inc);
1670 struct rmxp_tao *taop = rmx_taop(rt->rt_rmx);
1672 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu)
1673 mtu = rt->rt_rmx.rmx_mtu;
1677 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1678 sizeof(struct tcpiphdr));
1681 * XXX - The following conditional probably violates the TCP
1682 * spec. The problem is that, since we don't know the
1683 * other end's MSS, we are supposed to use a conservative
1684 * default. But, if we do that, then MTU discovery will
1685 * never actually take place, because the conservative
1686 * default is much less than the MTUs typically seen
1687 * on the Internet today. For the moment, we'll sweep
1688 * this under the carpet.
1690 * The conservative default might not actually be a problem
1691 * if the only case this occurs is when sending an initial
1692 * SYN with options and data to a host we've never talked
1693 * to before. Then, they will reply with an MSS value which
1694 * will get recorded and the new parameters should get
1695 * recomputed. For Further Study.
1697 if (taop->tao_mssopt != 0 && taop->tao_mssopt < maxopd)
1698 maxopd = taop->tao_mssopt;
1702 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1703 sizeof(struct tcpiphdr));
1705 if (tp->t_maxopd <= maxopd)
1707 tp->t_maxopd = maxopd;
1710 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) ==
1711 (TF_REQ_TSTMP | TF_RCVD_TSTMP))
1712 mss -= TCPOLEN_TSTAMP_APPA;
1714 if ((tp->t_flags & (TF_REQ_CC | TF_RCVD_CC | TF_NOOPT)) ==
1715 (TF_REQ_CC | TF_RCVD_CC))
1716 mss -= TCPOLEN_CC_APPA;
1718 /* round down to multiple of MCLBYTES */
1719 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */
1721 mss &= ~(MCLBYTES - 1);
1724 mss = (mss / MCLBYTES) * MCLBYTES;
1727 if (so->so_snd.ssb_hiwat < mss)
1728 mss = so->so_snd.ssb_hiwat;
1732 tp->snd_nxt = tp->snd_una;
1734 tcpstat.tcps_mturesent++;
1738 * Look-up the routing entry to the peer of this inpcb. If no route
1739 * is found and it cannot be allocated the return NULL. This routine
1740 * is called by TCP routines that access the rmx structure and by tcp_mss
1741 * to get the interface MTU.
1744 tcp_rtlookup(struct in_conninfo *inc)
1746 struct route *ro = &inc->inc_route;
1748 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) {
1749 /* No route yet, so try to acquire one */
1750 if (inc->inc_faddr.s_addr != INADDR_ANY) {
1752 * unused portions of the structure MUST be zero'd
1753 * out because rtalloc() treats it as opaque data
1755 bzero(&ro->ro_dst, sizeof(struct sockaddr_in));
1756 ro->ro_dst.sa_family = AF_INET;
1757 ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
1758 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
1768 tcp_rtlookup6(struct in_conninfo *inc)
1770 struct route_in6 *ro6 = &inc->inc6_route;
1772 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) {
1773 /* No route yet, so try to acquire one */
1774 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
1776 * unused portions of the structure MUST be zero'd
1777 * out because rtalloc() treats it as opaque data
1779 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6));
1780 ro6->ro_dst.sin6_family = AF_INET6;
1781 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6);
1782 ro6->ro_dst.sin6_addr = inc->inc6_faddr;
1783 rtalloc((struct route *)ro6);
1786 return (ro6->ro_rt);
1791 /* compute ESP/AH header size for TCP, including outer IP header. */
1793 ipsec_hdrsiz_tcp(struct tcpcb *tp)
1801 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
1803 MGETHDR(m, MB_DONTWAIT, MT_DATA);
1808 if (inp->inp_vflag & INP_IPV6) {
1809 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1811 th = (struct tcphdr *)(ip6 + 1);
1812 m->m_pkthdr.len = m->m_len =
1813 sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1814 tcp_fillheaders(tp, ip6, th);
1815 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1819 ip = mtod(m, struct ip *);
1820 th = (struct tcphdr *)(ip + 1);
1821 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
1822 tcp_fillheaders(tp, ip, th);
1823 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1832 * Return a pointer to the cached information about the remote host.
1833 * The cached information is stored in the protocol specific part of
1834 * the route metrics.
1837 tcp_gettaocache(struct in_conninfo *inc)
1842 if (inc->inc_isipv6)
1843 rt = tcp_rtlookup6(inc);
1846 rt = tcp_rtlookup(inc);
1848 /* Make sure this is a host route and is up. */
1850 (rt->rt_flags & (RTF_UP | RTF_HOST)) != (RTF_UP | RTF_HOST))
1853 return (rmx_taop(rt->rt_rmx));
1857 * Clear all the TAO cache entries, called from tcp_init.
1860 * This routine is just an empty one, because we assume that the routing
1861 * routing tables are initialized at the same time when TCP, so there is
1862 * nothing in the cache left over.
1865 tcp_cleartaocache(void)
1870 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
1872 * This code attempts to calculate the bandwidth-delay product as a
1873 * means of determining the optimal window size to maximize bandwidth,
1874 * minimize RTT, and avoid the over-allocation of buffers on interfaces and
1875 * routers. This code also does a fairly good job keeping RTTs in check
1876 * across slow links like modems. We implement an algorithm which is very
1877 * similar (but not meant to be) TCP/Vegas. The code operates on the
1878 * transmitter side of a TCP connection and so only effects the transmit
1879 * side of the connection.
1881 * BACKGROUND: TCP makes no provision for the management of buffer space
1882 * at the end points or at the intermediate routers and switches. A TCP
1883 * stream, whether using NewReno or not, will eventually buffer as
1884 * many packets as it is able and the only reason this typically works is
1885 * due to the fairly small default buffers made available for a connection
1886 * (typicaly 16K or 32K). As machines use larger windows and/or window
1887 * scaling it is now fairly easy for even a single TCP connection to blow-out
1888 * all available buffer space not only on the local interface, but on
1889 * intermediate routers and switches as well. NewReno makes a misguided
1890 * attempt to 'solve' this problem by waiting for an actual failure to occur,
1891 * then backing off, then steadily increasing the window again until another
1892 * failure occurs, ad-infinitum. This results in terrible oscillation that
1893 * is only made worse as network loads increase and the idea of intentionally
1894 * blowing out network buffers is, frankly, a terrible way to manage network
1897 * It is far better to limit the transmit window prior to the failure
1898 * condition being achieved. There are two general ways to do this: First
1899 * you can 'scan' through different transmit window sizes and locate the
1900 * point where the RTT stops increasing, indicating that you have filled the
1901 * pipe, then scan backwards until you note that RTT stops decreasing, then
1902 * repeat ad-infinitum. This method works in principle but has severe
1903 * implementation issues due to RTT variances, timer granularity, and
1904 * instability in the algorithm which can lead to many false positives and
1905 * create oscillations as well as interact badly with other TCP streams
1906 * implementing the same algorithm.
1908 * The second method is to limit the window to the bandwidth delay product
1909 * of the link. This is the method we implement. RTT variances and our
1910 * own manipulation of the congestion window, bwnd, can potentially
1911 * destabilize the algorithm. For this reason we have to stabilize the
1912 * elements used to calculate the window. We do this by using the minimum
1913 * observed RTT, the long term average of the observed bandwidth, and
1914 * by adding two segments worth of slop. It isn't perfect but it is able
1915 * to react to changing conditions and gives us a very stable basis on
1916 * which to extend the algorithm.
1919 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq)
1927 * If inflight_enable is disabled in the middle of a tcp connection,
1928 * make sure snd_bwnd is effectively disabled.
1930 if (!tcp_inflight_enable) {
1931 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1932 tp->snd_bandwidth = 0;
1937 * Validate the delta time. If a connection is new or has been idle
1938 * a long time we have to reset the bandwidth calculator.
1941 delta_ticks = save_ticks - tp->t_bw_rtttime;
1942 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) {
1943 tp->t_bw_rtttime = ticks;
1944 tp->t_bw_rtseq = ack_seq;
1945 if (tp->snd_bandwidth == 0)
1946 tp->snd_bandwidth = tcp_inflight_min;
1949 if (delta_ticks == 0)
1953 * Sanity check, plus ignore pure window update acks.
1955 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0)
1959 * Figure out the bandwidth. Due to the tick granularity this
1960 * is a very rough number and it MUST be averaged over a fairly
1961 * long period of time. XXX we need to take into account a link
1962 * that is not using all available bandwidth, but for now our
1963 * slop will ramp us up if this case occurs and the bandwidth later
1966 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks;
1967 tp->t_bw_rtttime = save_ticks;
1968 tp->t_bw_rtseq = ack_seq;
1969 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4;
1971 tp->snd_bandwidth = bw;
1974 * Calculate the semi-static bandwidth delay product, plus two maximal
1975 * segments. The additional slop puts us squarely in the sweet
1976 * spot and also handles the bandwidth run-up case. Without the
1977 * slop we could be locking ourselves into a lower bandwidth.
1979 * Situations Handled:
1980 * (1) Prevents over-queueing of packets on LANs, especially on
1981 * high speed LANs, allowing larger TCP buffers to be
1982 * specified, and also does a good job preventing
1983 * over-queueing of packets over choke points like modems
1984 * (at least for the transmit side).
1986 * (2) Is able to handle changing network loads (bandwidth
1987 * drops so bwnd drops, bandwidth increases so bwnd
1990 * (3) Theoretically should stabilize in the face of multiple
1991 * connections implementing the same algorithm (this may need
1994 * (4) Stability value (defaults to 20 = 2 maximal packets) can
1995 * be adjusted with a sysctl but typically only needs to be on
1996 * very slow connections. A value no smaller then 5 should
1997 * be used, but only reduce this default if you have no other
2001 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2)
2002 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) +
2003 tcp_inflight_stab * (int)tp->t_maxseg / 10;
2006 if (tcp_inflight_debug > 0) {
2008 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) {
2010 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n",
2011 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd);
2014 if ((long)bwnd < tcp_inflight_min)
2015 bwnd = tcp_inflight_min;
2016 if (bwnd > tcp_inflight_max)
2017 bwnd = tcp_inflight_max;
2018 if ((long)bwnd < tp->t_maxseg * 2)
2019 bwnd = tp->t_maxseg * 2;
2020 tp->snd_bwnd = bwnd;