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[dragonfly.git] / sys / netinet / tcp_subr.c
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1 /*
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
6 * by Jeffrey M. Hsu.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of The DragonFly Project nor the names of its
17 * contributors may be used to endorse or promote products derived
18 * from this software without specific, prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
35 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
36 * The Regents of the University of California. All rights reserved.
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
40 * are met:
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 * notice, this list of conditions and the following disclaimer in the
45 * documentation and/or other materials provided with the distribution.
46 * 3. All advertising materials mentioning features or use of this software
47 * must display the following acknowledgement:
48 * This product includes software developed by the University of
49 * California, Berkeley and its contributors.
50 * 4. Neither the name of the University nor the names of its contributors
51 * may be used to endorse or promote products derived from this software
52 * without specific prior written permission.
54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64 * SUCH DAMAGE.
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>
83 #include <sys/mbuf.h>
84 #ifdef INET6
85 #include <sys/domain.h>
86 #endif
87 #include <sys/proc.h>
88 #include <sys/priv.h>
89 #include <sys/socket.h>
90 #include <sys/socketvar.h>
91 #include <sys/protosw.h>
92 #include <sys/random.h>
93 #include <sys/in_cksum.h>
94 #include <sys/ktr.h>
96 #include <vm/vm_zone.h>
98 #include <net/route.h>
99 #include <net/if.h>
100 #include <net/netisr.h>
102 #define _IP_VHL
103 #include <netinet/in.h>
104 #include <netinet/in_systm.h>
105 #include <netinet/ip.h>
106 #include <netinet/ip6.h>
107 #include <netinet/in_pcb.h>
108 #include <netinet6/in6_pcb.h>
109 #include <netinet/in_var.h>
110 #include <netinet/ip_var.h>
111 #include <netinet6/ip6_var.h>
112 #include <netinet/ip_icmp.h>
113 #ifdef INET6
114 #include <netinet/icmp6.h>
115 #endif
116 #include <netinet/tcp.h>
117 #include <netinet/tcp_fsm.h>
118 #include <netinet/tcp_seq.h>
119 #include <netinet/tcp_timer.h>
120 #include <netinet/tcp_timer2.h>
121 #include <netinet/tcp_var.h>
122 #include <netinet6/tcp6_var.h>
123 #include <netinet/tcpip.h>
124 #ifdef TCPDEBUG
125 #include <netinet/tcp_debug.h>
126 #endif
127 #include <netinet6/ip6protosw.h>
129 #ifdef IPSEC
130 #include <netinet6/ipsec.h>
131 #ifdef INET6
132 #include <netinet6/ipsec6.h>
133 #endif
134 #endif
136 #ifdef FAST_IPSEC
137 #include <netproto/ipsec/ipsec.h>
138 #ifdef INET6
139 #include <netproto/ipsec/ipsec6.h>
140 #endif
141 #define IPSEC
142 #endif
144 #include <sys/md5.h>
145 #include <sys/msgport2.h>
146 #include <machine/smp.h>
148 #include <net/netmsg2.h>
150 #if !defined(KTR_TCP)
151 #define KTR_TCP KTR_ALL
152 #endif
153 KTR_INFO_MASTER(tcp);
154 KTR_INFO(KTR_TCP, tcp, rxmsg, 0, "tcp getmsg", 0);
155 KTR_INFO(KTR_TCP, tcp, wait, 1, "tcp waitmsg", 0);
156 KTR_INFO(KTR_TCP, tcp, delayed, 2, "tcp execute delayed ops", 0);
157 #define logtcp(name) KTR_LOG(tcp_ ## name)
159 struct inpcbinfo tcbinfo[MAXCPU];
160 struct tcpcbackqhead tcpcbackq[MAXCPU];
162 int tcp_mpsafe_proto = 0;
163 TUNABLE_INT("net.inet.tcp.mpsafe_proto", &tcp_mpsafe_proto);
165 static int tcp_mpsafe_thread = NETMSG_SERVICE_ADAPTIVE;
166 TUNABLE_INT("net.inet.tcp.mpsafe_thread", &tcp_mpsafe_thread);
167 SYSCTL_INT(_net_inet_tcp, OID_AUTO, mpsafe_thread, CTLFLAG_RW,
168 &tcp_mpsafe_thread, 0,
169 "0:BGL, 1:Adaptive BGL, 2:No BGL(experimental)");
171 int tcp_mssdflt = TCP_MSS;
172 SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW,
173 &tcp_mssdflt, 0, "Default TCP Maximum Segment Size");
175 #ifdef INET6
176 int tcp_v6mssdflt = TCP6_MSS;
177 SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW,
178 &tcp_v6mssdflt, 0, "Default TCP Maximum Segment Size for IPv6");
179 #endif
182 * Minimum MSS we accept and use. This prevents DoS attacks where
183 * we are forced to a ridiculous low MSS like 20 and send hundreds
184 * of packets instead of one. The effect scales with the available
185 * bandwidth and quickly saturates the CPU and network interface
186 * with packet generation and sending. Set to zero to disable MINMSS
187 * checking. This setting prevents us from sending too small packets.
189 int tcp_minmss = TCP_MINMSS;
190 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW,
191 &tcp_minmss , 0, "Minmum TCP Maximum Segment Size");
193 #if 0
194 static int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
195 SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW,
196 &tcp_rttdflt, 0, "Default maximum TCP Round Trip Time");
197 #endif
199 int tcp_do_rfc1323 = 1;
200 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
201 &tcp_do_rfc1323, 0, "Enable rfc1323 (high performance TCP) extensions");
203 int tcp_do_rfc1644 = 0;
204 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW,
205 &tcp_do_rfc1644, 0, "Enable rfc1644 (TTCP) extensions");
207 static int tcp_tcbhashsize = 0;
208 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD,
209 &tcp_tcbhashsize, 0, "Size of TCP control block hashtable");
211 static int do_tcpdrain = 1;
212 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
213 "Enable tcp_drain routine for extra help when low on mbufs");
215 /* XXX JH */
216 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
217 &tcbinfo[0].ipi_count, 0, "Number of active PCBs");
219 static int icmp_may_rst = 1;
220 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0,
221 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
223 static int tcp_isn_reseed_interval = 0;
224 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
225 &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret");
228 * TCP bandwidth limiting sysctls. Note that the default lower bound of
229 * 1024 exists only for debugging. A good production default would be
230 * something like 6100.
232 static int tcp_inflight_enable = 0;
233 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW,
234 &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting");
236 static int tcp_inflight_debug = 0;
237 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW,
238 &tcp_inflight_debug, 0, "Debug TCP inflight calculations");
240 static int tcp_inflight_min = 6144;
241 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW,
242 &tcp_inflight_min, 0, "Lower bound for TCP inflight window");
244 static int tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT;
245 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW,
246 &tcp_inflight_max, 0, "Upper bound for TCP inflight window");
248 static int tcp_inflight_stab = 20;
249 SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW,
250 &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 2 packets)");
252 static MALLOC_DEFINE(M_TCPTEMP, "tcptemp", "TCP Templates for Keepalives");
253 static struct malloc_pipe tcptemp_mpipe;
255 static void tcp_willblock(int);
256 static void tcp_cleartaocache (void);
257 static void tcp_notify (struct inpcb *, int);
259 struct tcp_stats tcpstats_percpu[MAXCPU];
260 #ifdef SMP
261 static int
262 sysctl_tcpstats(SYSCTL_HANDLER_ARGS)
264 int cpu, error = 0;
266 for (cpu = 0; cpu < ncpus; ++cpu) {
267 if ((error = SYSCTL_OUT(req, &tcpstats_percpu[cpu],
268 sizeof(struct tcp_stats))))
269 break;
270 if ((error = SYSCTL_IN(req, &tcpstats_percpu[cpu],
271 sizeof(struct tcp_stats))))
272 break;
275 return (error);
277 SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW),
278 0, 0, sysctl_tcpstats, "S,tcp_stats", "TCP statistics");
279 #else
280 SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW,
281 &tcpstat, tcp_stats, "TCP statistics");
282 #endif
285 * Target size of TCP PCB hash tables. Must be a power of two.
287 * Note that this can be overridden by the kernel environment
288 * variable net.inet.tcp.tcbhashsize
290 #ifndef TCBHASHSIZE
291 #define TCBHASHSIZE 512
292 #endif
295 * This is the actual shape of what we allocate using the zone
296 * allocator. Doing it this way allows us to protect both structures
297 * using the same generation count, and also eliminates the overhead
298 * of allocating tcpcbs separately. By hiding the structure here,
299 * we avoid changing most of the rest of the code (although it needs
300 * to be changed, eventually, for greater efficiency).
302 #define ALIGNMENT 32
303 #define ALIGNM1 (ALIGNMENT - 1)
304 struct inp_tp {
305 union {
306 struct inpcb inp;
307 char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1];
308 } inp_tp_u;
309 struct tcpcb tcb;
310 struct tcp_callout inp_tp_rexmt;
311 struct tcp_callout inp_tp_persist;
312 struct tcp_callout inp_tp_keep;
313 struct tcp_callout inp_tp_2msl;
314 struct tcp_callout inp_tp_delack;
315 struct netmsg_tcp_timer inp_tp_timermsg;
317 #undef ALIGNMENT
318 #undef ALIGNM1
321 * Tcp initialization
323 void
324 tcp_init(void)
326 struct inpcbporthead *porthashbase;
327 u_long porthashmask;
328 struct vm_zone *ipi_zone;
329 int hashsize = TCBHASHSIZE;
330 int cpu;
333 * note: tcptemp is used for keepalives, and it is ok for an
334 * allocation to fail so do not specify MPF_INT.
336 mpipe_init(&tcptemp_mpipe, M_TCPTEMP, sizeof(struct tcptemp),
337 25, -1, 0, NULL);
339 tcp_ccgen = 1;
340 tcp_cleartaocache();
342 tcp_delacktime = TCPTV_DELACK;
343 tcp_keepinit = TCPTV_KEEP_INIT;
344 tcp_keepidle = TCPTV_KEEP_IDLE;
345 tcp_keepintvl = TCPTV_KEEPINTVL;
346 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
347 tcp_msl = TCPTV_MSL;
348 tcp_rexmit_min = TCPTV_MIN;
349 tcp_rexmit_slop = TCPTV_CPU_VAR;
351 TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
352 if (!powerof2(hashsize)) {
353 kprintf("WARNING: TCB hash size not a power of 2\n");
354 hashsize = 512; /* safe default */
356 tcp_tcbhashsize = hashsize;
357 porthashbase = hashinit(hashsize, M_PCB, &porthashmask);
358 ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets,
359 ZONE_INTERRUPT, 0);
361 for (cpu = 0; cpu < ncpus2; cpu++) {
362 in_pcbinfo_init(&tcbinfo[cpu]);
363 tcbinfo[cpu].cpu = cpu;
364 tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB,
365 &tcbinfo[cpu].hashmask);
366 tcbinfo[cpu].porthashbase = porthashbase;
367 tcbinfo[cpu].porthashmask = porthashmask;
368 tcbinfo[cpu].wildcardhashbase = hashinit(hashsize, M_PCB,
369 &tcbinfo[cpu].wildcardhashmask);
370 tcbinfo[cpu].ipi_zone = ipi_zone;
371 TAILQ_INIT(&tcpcbackq[cpu]);
374 tcp_reass_maxseg = nmbclusters / 16;
375 TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments", &tcp_reass_maxseg);
377 #ifdef INET6
378 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
379 #else
380 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
381 #endif
382 if (max_protohdr < TCP_MINPROTOHDR)
383 max_protohdr = TCP_MINPROTOHDR;
384 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
385 panic("tcp_init");
386 #undef TCP_MINPROTOHDR
389 * Initialize TCP statistics counters for each CPU.
391 #ifdef SMP
392 for (cpu = 0; cpu < ncpus; ++cpu) {
393 bzero(&tcpstats_percpu[cpu], sizeof(struct tcp_stats));
395 #else
396 bzero(&tcpstat, sizeof(struct tcp_stats));
397 #endif
399 syncache_init();
400 tcp_thread_init();
403 void
404 tcpmsg_service_loop(void *dummy)
406 struct netmsg *msg;
407 int mplocked;
410 * Thread was started with TDF_MPSAFE
412 mplocked = 0;
414 while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) {
415 do {
416 logtcp(rxmsg);
417 mplocked = netmsg_service(msg, tcp_mpsafe_thread,
418 mplocked);
419 } while ((msg = lwkt_getport(&curthread->td_msgport)) != NULL);
421 logtcp(delayed);
422 tcp_willblock(mplocked);
423 logtcp(wait);
427 static void
428 tcp_willblock(int mplocked)
430 struct tcpcb *tp;
431 int cpu = mycpu->gd_cpuid;
432 int unlock = 0;
434 if (!mplocked && !tcp_mpsafe_proto) {
435 if (TAILQ_EMPTY(&tcpcbackq[cpu]))
436 return;
438 get_mplock();
439 mplocked = 1;
440 unlock = 1;
443 while ((tp = TAILQ_FIRST(&tcpcbackq[cpu])) != NULL) {
444 KKASSERT(tp->t_flags & TF_ONOUTPUTQ);
445 tp->t_flags &= ~TF_ONOUTPUTQ;
446 TAILQ_REMOVE(&tcpcbackq[cpu], tp, t_outputq);
447 tcp_output(tp);
450 if (unlock)
451 rel_mplock();
456 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
457 * tcp_template used to store this data in mbufs, but we now recopy it out
458 * of the tcpcb each time to conserve mbufs.
460 void
461 tcp_fillheaders(struct tcpcb *tp, void *ip_ptr, void *tcp_ptr)
463 struct inpcb *inp = tp->t_inpcb;
464 struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr;
466 #ifdef INET6
467 if (inp->inp_vflag & INP_IPV6) {
468 struct ip6_hdr *ip6;
470 ip6 = (struct ip6_hdr *)ip_ptr;
471 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
472 (inp->in6p_flowinfo & IPV6_FLOWINFO_MASK);
473 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
474 (IPV6_VERSION & IPV6_VERSION_MASK);
475 ip6->ip6_nxt = IPPROTO_TCP;
476 ip6->ip6_plen = sizeof(struct tcphdr);
477 ip6->ip6_src = inp->in6p_laddr;
478 ip6->ip6_dst = inp->in6p_faddr;
479 tcp_hdr->th_sum = 0;
480 } else
481 #endif
483 struct ip *ip = (struct ip *) ip_ptr;
485 ip->ip_vhl = IP_VHL_BORING;
486 ip->ip_tos = 0;
487 ip->ip_len = 0;
488 ip->ip_id = 0;
489 ip->ip_off = 0;
490 ip->ip_ttl = 0;
491 ip->ip_sum = 0;
492 ip->ip_p = IPPROTO_TCP;
493 ip->ip_src = inp->inp_laddr;
494 ip->ip_dst = inp->inp_faddr;
495 tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr,
496 ip->ip_dst.s_addr,
497 htons(sizeof(struct tcphdr) + IPPROTO_TCP));
500 tcp_hdr->th_sport = inp->inp_lport;
501 tcp_hdr->th_dport = inp->inp_fport;
502 tcp_hdr->th_seq = 0;
503 tcp_hdr->th_ack = 0;
504 tcp_hdr->th_x2 = 0;
505 tcp_hdr->th_off = 5;
506 tcp_hdr->th_flags = 0;
507 tcp_hdr->th_win = 0;
508 tcp_hdr->th_urp = 0;
512 * Create template to be used to send tcp packets on a connection.
513 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
514 * use for this function is in keepalives, which use tcp_respond.
516 struct tcptemp *
517 tcp_maketemplate(struct tcpcb *tp)
519 struct tcptemp *tmp;
521 if ((tmp = mpipe_alloc_nowait(&tcptemp_mpipe)) == NULL)
522 return (NULL);
523 tcp_fillheaders(tp, &tmp->tt_ipgen, &tmp->tt_t);
524 return (tmp);
527 void
528 tcp_freetemplate(struct tcptemp *tmp)
530 mpipe_free(&tcptemp_mpipe, tmp);
534 * Send a single message to the TCP at address specified by
535 * the given TCP/IP header. If m == NULL, then we make a copy
536 * of the tcpiphdr at ti and send directly to the addressed host.
537 * This is used to force keep alive messages out using the TCP
538 * template for a connection. If flags are given then we send
539 * a message back to the TCP which originated the * segment ti,
540 * and discard the mbuf containing it and any other attached mbufs.
542 * In any case the ack and sequence number of the transmitted
543 * segment are as specified by the parameters.
545 * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
547 void
548 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
549 tcp_seq ack, tcp_seq seq, int flags)
551 int tlen;
552 int win = 0;
553 struct route *ro = NULL;
554 struct route sro;
555 struct ip *ip = ipgen;
556 struct tcphdr *nth;
557 int ipflags = 0;
558 struct route_in6 *ro6 = NULL;
559 struct route_in6 sro6;
560 struct ip6_hdr *ip6 = ipgen;
561 boolean_t use_tmpro = TRUE;
562 #ifdef INET6
563 boolean_t isipv6 = (IP_VHL_V(ip->ip_vhl) == 6);
564 #else
565 const boolean_t isipv6 = FALSE;
566 #endif
568 if (tp != NULL) {
569 if (!(flags & TH_RST)) {
570 win = ssb_space(&tp->t_inpcb->inp_socket->so_rcv);
571 if (win < 0)
572 win = 0;
573 if (win > (long)TCP_MAXWIN << tp->rcv_scale)
574 win = (long)TCP_MAXWIN << tp->rcv_scale;
577 * Don't use the route cache of a listen socket,
578 * it is not MPSAFE; use temporary route cache.
580 if (tp->t_state != TCPS_LISTEN) {
581 if (isipv6)
582 ro6 = &tp->t_inpcb->in6p_route;
583 else
584 ro = &tp->t_inpcb->inp_route;
585 use_tmpro = FALSE;
588 if (use_tmpro) {
589 if (isipv6) {
590 ro6 = &sro6;
591 bzero(ro6, sizeof *ro6);
592 } else {
593 ro = &sro;
594 bzero(ro, sizeof *ro);
597 if (m == NULL) {
598 m = m_gethdr(MB_DONTWAIT, MT_HEADER);
599 if (m == NULL)
600 return;
601 tlen = 0;
602 m->m_data += max_linkhdr;
603 if (isipv6) {
604 bcopy(ip6, mtod(m, caddr_t), sizeof(struct ip6_hdr));
605 ip6 = mtod(m, struct ip6_hdr *);
606 nth = (struct tcphdr *)(ip6 + 1);
607 } else {
608 bcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
609 ip = mtod(m, struct ip *);
610 nth = (struct tcphdr *)(ip + 1);
612 bcopy(th, nth, sizeof(struct tcphdr));
613 flags = TH_ACK;
614 } else {
615 m_freem(m->m_next);
616 m->m_next = NULL;
617 m->m_data = (caddr_t)ipgen;
618 /* m_len is set later */
619 tlen = 0;
620 #define xchg(a, b, type) { type t; t = a; a = b; b = t; }
621 if (isipv6) {
622 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
623 nth = (struct tcphdr *)(ip6 + 1);
624 } else {
625 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long);
626 nth = (struct tcphdr *)(ip + 1);
628 if (th != nth) {
630 * this is usually a case when an extension header
631 * exists between the IPv6 header and the
632 * TCP header.
634 nth->th_sport = th->th_sport;
635 nth->th_dport = th->th_dport;
637 xchg(nth->th_dport, nth->th_sport, n_short);
638 #undef xchg
640 if (isipv6) {
641 ip6->ip6_flow = 0;
642 ip6->ip6_vfc = IPV6_VERSION;
643 ip6->ip6_nxt = IPPROTO_TCP;
644 ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + tlen));
645 tlen += sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
646 } else {
647 tlen += sizeof(struct tcpiphdr);
648 ip->ip_len = tlen;
649 ip->ip_ttl = ip_defttl;
651 m->m_len = tlen;
652 m->m_pkthdr.len = tlen;
653 m->m_pkthdr.rcvif = NULL;
654 nth->th_seq = htonl(seq);
655 nth->th_ack = htonl(ack);
656 nth->th_x2 = 0;
657 nth->th_off = sizeof(struct tcphdr) >> 2;
658 nth->th_flags = flags;
659 if (tp != NULL)
660 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
661 else
662 nth->th_win = htons((u_short)win);
663 nth->th_urp = 0;
664 if (isipv6) {
665 nth->th_sum = 0;
666 nth->th_sum = in6_cksum(m, IPPROTO_TCP,
667 sizeof(struct ip6_hdr),
668 tlen - sizeof(struct ip6_hdr));
669 ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL,
670 (ro6 && ro6->ro_rt) ?
671 ro6->ro_rt->rt_ifp : NULL);
672 } else {
673 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
674 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
675 m->m_pkthdr.csum_flags = CSUM_TCP;
676 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
678 #ifdef TCPDEBUG
679 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
680 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
681 #endif
682 if (isipv6) {
683 ip6_output(m, NULL, ro6, ipflags, NULL, NULL,
684 tp ? tp->t_inpcb : NULL);
685 if ((ro6 == &sro6) && (ro6->ro_rt != NULL)) {
686 RTFREE(ro6->ro_rt);
687 ro6->ro_rt = NULL;
689 } else {
690 ipflags |= IP_DEBUGROUTE;
691 ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL);
692 if ((ro == &sro) && (ro->ro_rt != NULL)) {
693 RTFREE(ro->ro_rt);
694 ro->ro_rt = NULL;
700 * Create a new TCP control block, making an
701 * empty reassembly queue and hooking it to the argument
702 * protocol control block. The `inp' parameter must have
703 * come from the zone allocator set up in tcp_init().
705 struct tcpcb *
706 tcp_newtcpcb(struct inpcb *inp)
708 struct inp_tp *it;
709 struct tcpcb *tp;
710 #ifdef INET6
711 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0);
712 #else
713 const boolean_t isipv6 = FALSE;
714 #endif
716 it = (struct inp_tp *)inp;
717 tp = &it->tcb;
718 bzero(tp, sizeof(struct tcpcb));
719 LIST_INIT(&tp->t_segq);
720 tp->t_maxseg = tp->t_maxopd = isipv6 ? tcp_v6mssdflt : tcp_mssdflt;
722 /* Set up our timeouts. */
723 tp->tt_rexmt = &it->inp_tp_rexmt;
724 tp->tt_persist = &it->inp_tp_persist;
725 tp->tt_keep = &it->inp_tp_keep;
726 tp->tt_2msl = &it->inp_tp_2msl;
727 tp->tt_delack = &it->inp_tp_delack;
728 tcp_inittimers(tp);
731 * Zero out timer message. We don't create it here,
732 * since the current CPU may not be the owner of this
733 * inpcb.
735 tp->tt_msg = &it->inp_tp_timermsg;
736 bzero(tp->tt_msg, sizeof(*tp->tt_msg));
738 if (tcp_do_rfc1323)
739 tp->t_flags = (TF_REQ_SCALE | TF_REQ_TSTMP);
740 if (tcp_do_rfc1644)
741 tp->t_flags |= TF_REQ_CC;
742 tp->t_inpcb = inp; /* XXX */
743 tp->t_state = TCPS_CLOSED;
745 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
746 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
747 * reasonable initial retransmit time.
749 tp->t_srtt = TCPTV_SRTTBASE;
750 tp->t_rttvar =
751 ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
752 tp->t_rttmin = tcp_rexmit_min;
753 tp->t_rxtcur = TCPTV_RTOBASE;
754 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
755 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
756 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
757 tp->t_rcvtime = ticks;
759 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
760 * because the socket may be bound to an IPv6 wildcard address,
761 * which may match an IPv4-mapped IPv6 address.
763 inp->inp_ip_ttl = ip_defttl;
764 inp->inp_ppcb = tp;
765 tcp_sack_tcpcb_init(tp);
766 return (tp); /* XXX */
770 * Drop a TCP connection, reporting the specified error.
771 * If connection is synchronized, then send a RST to peer.
773 struct tcpcb *
774 tcp_drop(struct tcpcb *tp, int error)
776 struct socket *so = tp->t_inpcb->inp_socket;
778 if (TCPS_HAVERCVDSYN(tp->t_state)) {
779 tp->t_state = TCPS_CLOSED;
780 tcp_output(tp);
781 tcpstat.tcps_drops++;
782 } else
783 tcpstat.tcps_conndrops++;
784 if (error == ETIMEDOUT && tp->t_softerror)
785 error = tp->t_softerror;
786 so->so_error = error;
787 return (tcp_close(tp));
790 #ifdef SMP
792 struct netmsg_remwildcard {
793 struct netmsg nm_netmsg;
794 struct inpcb *nm_inp;
795 struct inpcbinfo *nm_pcbinfo;
796 #if defined(INET6)
797 int nm_isinet6;
798 #else
799 int nm_unused01;
800 #endif
804 * Wildcard inpcb's on SMP boxes must be removed from all cpus before the
805 * inp can be detached. We do this by cycling through the cpus, ending up
806 * on the cpu controlling the inp last and then doing the disconnect.
808 static void
809 in_pcbremwildcardhash_handler(struct netmsg *msg0)
811 struct netmsg_remwildcard *msg = (struct netmsg_remwildcard *)msg0;
812 int cpu;
814 cpu = msg->nm_pcbinfo->cpu;
816 if (cpu == msg->nm_inp->inp_pcbinfo->cpu) {
817 /* note: detach removes any wildcard hash entry */
818 #ifdef INET6
819 if (msg->nm_isinet6)
820 in6_pcbdetach(msg->nm_inp);
821 else
822 #endif
823 in_pcbdetach(msg->nm_inp);
824 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0);
825 } else {
826 in_pcbremwildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo);
827 cpu = (cpu + 1) % ncpus2;
828 msg->nm_pcbinfo = &tcbinfo[cpu];
829 lwkt_forwardmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg);
833 #endif
836 * Close a TCP control block:
837 * discard all space held by the tcp
838 * discard internet protocol block
839 * wake up any sleepers
841 struct tcpcb *
842 tcp_close(struct tcpcb *tp)
844 struct tseg_qent *q;
845 struct inpcb *inp = tp->t_inpcb;
846 struct socket *so = inp->inp_socket;
847 struct rtentry *rt;
848 boolean_t dosavessthresh;
849 #ifdef SMP
850 int cpu;
851 #endif
852 #ifdef INET6
853 boolean_t isipv6 = ((inp->inp_vflag & INP_IPV6) != 0);
854 boolean_t isafinet6 = (INP_CHECK_SOCKAF(so, AF_INET6) != 0);
855 #else
856 const boolean_t isipv6 = FALSE;
857 #endif
860 * The tp is not instantly destroyed in the wildcard case. Setting
861 * the state to TCPS_TERMINATING will prevent the TCP stack from
862 * messing with it, though it should be noted that this change may
863 * not take effect on other cpus until we have chained the wildcard
864 * hash removal.
866 * XXX we currently depend on the BGL to synchronize the tp->t_state
867 * update and prevent other tcp protocol threads from accepting new
868 * connections on the listen socket we might be trying to close down.
870 KKASSERT(tp->t_state != TCPS_TERMINATING);
871 tp->t_state = TCPS_TERMINATING;
874 * Make sure that all of our timers are stopped before we
875 * delete the PCB. For listen TCP socket (tp->tt_msg == NULL),
876 * timers are never used. If timer message is never created
877 * (tp->tt_msg->tt_tcb == NULL), timers are never used too.
879 if (tp->tt_msg != NULL && tp->tt_msg->tt_tcb != NULL) {
880 tcp_callout_stop(tp, tp->tt_rexmt);
881 tcp_callout_stop(tp, tp->tt_persist);
882 tcp_callout_stop(tp, tp->tt_keep);
883 tcp_callout_stop(tp, tp->tt_2msl);
884 tcp_callout_stop(tp, tp->tt_delack);
887 if (tp->t_flags & TF_ONOUTPUTQ) {
888 KKASSERT(tp->tt_cpu == mycpu->gd_cpuid);
889 TAILQ_REMOVE(&tcpcbackq[tp->tt_cpu], tp, t_outputq);
890 tp->t_flags &= ~TF_ONOUTPUTQ;
894 * If we got enough samples through the srtt filter,
895 * save the rtt and rttvar in the routing entry.
896 * 'Enough' is arbitrarily defined as the 16 samples.
897 * 16 samples is enough for the srtt filter to converge
898 * to within 5% of the correct value; fewer samples and
899 * we could save a very bogus rtt.
901 * Don't update the default route's characteristics and don't
902 * update anything that the user "locked".
904 if (tp->t_rttupdated >= 16) {
905 u_long i = 0;
907 if (isipv6) {
908 struct sockaddr_in6 *sin6;
910 if ((rt = inp->in6p_route.ro_rt) == NULL)
911 goto no_valid_rt;
912 sin6 = (struct sockaddr_in6 *)rt_key(rt);
913 if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr))
914 goto no_valid_rt;
915 } else
916 if ((rt = inp->inp_route.ro_rt) == NULL ||
917 ((struct sockaddr_in *)rt_key(rt))->
918 sin_addr.s_addr == INADDR_ANY)
919 goto no_valid_rt;
921 if (!(rt->rt_rmx.rmx_locks & RTV_RTT)) {
922 i = tp->t_srtt * (RTM_RTTUNIT / (hz * TCP_RTT_SCALE));
923 if (rt->rt_rmx.rmx_rtt && i)
925 * filter this update to half the old & half
926 * the new values, converting scale.
927 * See route.h and tcp_var.h for a
928 * description of the scaling constants.
930 rt->rt_rmx.rmx_rtt =
931 (rt->rt_rmx.rmx_rtt + i) / 2;
932 else
933 rt->rt_rmx.rmx_rtt = i;
934 tcpstat.tcps_cachedrtt++;
936 if (!(rt->rt_rmx.rmx_locks & RTV_RTTVAR)) {
937 i = tp->t_rttvar *
938 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE));
939 if (rt->rt_rmx.rmx_rttvar && i)
940 rt->rt_rmx.rmx_rttvar =
941 (rt->rt_rmx.rmx_rttvar + i) / 2;
942 else
943 rt->rt_rmx.rmx_rttvar = i;
944 tcpstat.tcps_cachedrttvar++;
947 * The old comment here said:
948 * update the pipelimit (ssthresh) if it has been updated
949 * already or if a pipesize was specified & the threshhold
950 * got below half the pipesize. I.e., wait for bad news
951 * before we start updating, then update on both good
952 * and bad news.
954 * But we want to save the ssthresh even if no pipesize is
955 * specified explicitly in the route, because such
956 * connections still have an implicit pipesize specified
957 * by the global tcp_sendspace. In the absence of a reliable
958 * way to calculate the pipesize, it will have to do.
960 i = tp->snd_ssthresh;
961 if (rt->rt_rmx.rmx_sendpipe != 0)
962 dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe/2);
963 else
964 dosavessthresh = (i < so->so_snd.ssb_hiwat/2);
965 if (dosavessthresh ||
966 (!(rt->rt_rmx.rmx_locks & RTV_SSTHRESH) && (i != 0) &&
967 (rt->rt_rmx.rmx_ssthresh != 0))) {
969 * convert the limit from user data bytes to
970 * packets then to packet data bytes.
972 i = (i + tp->t_maxseg / 2) / tp->t_maxseg;
973 if (i < 2)
974 i = 2;
975 i *= tp->t_maxseg +
976 (isipv6 ?
977 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
978 sizeof(struct tcpiphdr));
979 if (rt->rt_rmx.rmx_ssthresh)
980 rt->rt_rmx.rmx_ssthresh =
981 (rt->rt_rmx.rmx_ssthresh + i) / 2;
982 else
983 rt->rt_rmx.rmx_ssthresh = i;
984 tcpstat.tcps_cachedssthresh++;
988 no_valid_rt:
989 /* free the reassembly queue, if any */
990 while((q = LIST_FIRST(&tp->t_segq)) != NULL) {
991 LIST_REMOVE(q, tqe_q);
992 m_freem(q->tqe_m);
993 FREE(q, M_TSEGQ);
994 tcp_reass_qsize--;
996 /* throw away SACK blocks in scoreboard*/
997 if (TCP_DO_SACK(tp))
998 tcp_sack_cleanup(&tp->scb);
1000 inp->inp_ppcb = NULL;
1001 soisdisconnected(so);
1003 tcp_destroy_timermsg(tp);
1006 * Discard the inp. In the SMP case a wildcard inp's hash (created
1007 * by a listen socket or an INADDR_ANY udp socket) is replicated
1008 * for each protocol thread and must be removed in the context of
1009 * that thread. This is accomplished by chaining the message
1010 * through the cpus.
1012 * If the inp is not wildcarded we simply detach, which will remove
1013 * the any hashes still present for this inp.
1015 #ifdef SMP
1016 if (inp->inp_flags & INP_WILDCARD_MP) {
1017 struct netmsg_remwildcard *msg;
1019 cpu = (inp->inp_pcbinfo->cpu + 1) % ncpus2;
1020 msg = kmalloc(sizeof(struct netmsg_remwildcard),
1021 M_LWKTMSG, M_INTWAIT);
1022 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0,
1023 in_pcbremwildcardhash_handler);
1024 #ifdef INET6
1025 msg->nm_isinet6 = isafinet6;
1026 #endif
1027 msg->nm_inp = inp;
1028 msg->nm_pcbinfo = &tcbinfo[cpu];
1029 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg);
1030 } else
1031 #endif
1033 /* note: detach removes any wildcard hash entry */
1034 #ifdef INET6
1035 if (isafinet6)
1036 in6_pcbdetach(inp);
1037 else
1038 #endif
1039 in_pcbdetach(inp);
1041 tcpstat.tcps_closed++;
1042 return (NULL);
1045 static __inline void
1046 tcp_drain_oncpu(struct inpcbhead *head)
1048 struct inpcb *inpb;
1049 struct tcpcb *tcpb;
1050 struct tseg_qent *te;
1052 LIST_FOREACH(inpb, head, inp_list) {
1053 if (inpb->inp_flags & INP_PLACEMARKER)
1054 continue;
1055 if ((tcpb = intotcpcb(inpb))) {
1056 while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) {
1057 LIST_REMOVE(te, tqe_q);
1058 m_freem(te->tqe_m);
1059 FREE(te, M_TSEGQ);
1060 tcp_reass_qsize--;
1066 #ifdef SMP
1067 struct netmsg_tcp_drain {
1068 struct netmsg nm_netmsg;
1069 struct inpcbhead *nm_head;
1072 static void
1073 tcp_drain_handler(netmsg_t netmsg)
1075 struct netmsg_tcp_drain *nm = (void *)netmsg;
1077 tcp_drain_oncpu(nm->nm_head);
1078 lwkt_replymsg(&nm->nm_netmsg.nm_lmsg, 0);
1080 #endif
1082 void
1083 tcp_drain(void)
1085 #ifdef SMP
1086 int cpu;
1087 #endif
1089 if (!do_tcpdrain)
1090 return;
1093 * Walk the tcpbs, if existing, and flush the reassembly queue,
1094 * if there is one...
1095 * XXX: The "Net/3" implementation doesn't imply that the TCP
1096 * reassembly queue should be flushed, but in a situation
1097 * where we're really low on mbufs, this is potentially
1098 * useful.
1100 #ifdef SMP
1101 for (cpu = 0; cpu < ncpus2; cpu++) {
1102 struct netmsg_tcp_drain *msg;
1104 if (cpu == mycpu->gd_cpuid) {
1105 tcp_drain_oncpu(&tcbinfo[cpu].pcblisthead);
1106 } else {
1107 msg = kmalloc(sizeof(struct netmsg_tcp_drain),
1108 M_LWKTMSG, M_NOWAIT);
1109 if (msg == NULL)
1110 continue;
1111 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0,
1112 tcp_drain_handler);
1113 msg->nm_head = &tcbinfo[cpu].pcblisthead;
1114 lwkt_sendmsg(tcp_cport(cpu), &msg->nm_netmsg.nm_lmsg);
1117 #else
1118 tcp_drain_oncpu(&tcbinfo[0].pcblisthead);
1119 #endif
1123 * Notify a tcp user of an asynchronous error;
1124 * store error as soft error, but wake up user
1125 * (for now, won't do anything until can select for soft error).
1127 * Do not wake up user since there currently is no mechanism for
1128 * reporting soft errors (yet - a kqueue filter may be added).
1130 static void
1131 tcp_notify(struct inpcb *inp, int error)
1133 struct tcpcb *tp = intotcpcb(inp);
1136 * Ignore some errors if we are hooked up.
1137 * If connection hasn't completed, has retransmitted several times,
1138 * and receives a second error, give up now. This is better
1139 * than waiting a long time to establish a connection that
1140 * can never complete.
1142 if (tp->t_state == TCPS_ESTABLISHED &&
1143 (error == EHOSTUNREACH || error == ENETUNREACH ||
1144 error == EHOSTDOWN)) {
1145 return;
1146 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
1147 tp->t_softerror)
1148 tcp_drop(tp, error);
1149 else
1150 tp->t_softerror = error;
1151 #if 0
1152 wakeup(&so->so_timeo);
1153 sorwakeup(so);
1154 sowwakeup(so);
1155 #endif
1158 static int
1159 tcp_pcblist(SYSCTL_HANDLER_ARGS)
1161 int error, i, n;
1162 struct inpcb *marker;
1163 struct inpcb *inp;
1164 inp_gen_t gencnt;
1165 globaldata_t gd;
1166 int origcpu, ccpu;
1168 error = 0;
1169 n = 0;
1172 * The process of preparing the TCB list is too time-consuming and
1173 * resource-intensive to repeat twice on every request.
1175 if (req->oldptr == NULL) {
1176 for (ccpu = 0; ccpu < ncpus; ++ccpu) {
1177 gd = globaldata_find(ccpu);
1178 n += tcbinfo[gd->gd_cpuid].ipi_count;
1180 req->oldidx = (n + n/8 + 10) * sizeof(struct xtcpcb);
1181 return (0);
1184 if (req->newptr != NULL)
1185 return (EPERM);
1187 marker = kmalloc(sizeof(struct inpcb), M_TEMP, M_WAITOK|M_ZERO);
1188 marker->inp_flags |= INP_PLACEMARKER;
1191 * OK, now we're committed to doing something. Run the inpcb list
1192 * for each cpu in the system and construct the output. Use a
1193 * list placemarker to deal with list changes occuring during
1194 * copyout blockages (but otherwise depend on being on the correct
1195 * cpu to avoid races).
1197 origcpu = mycpu->gd_cpuid;
1198 for (ccpu = 1; ccpu <= ncpus && error == 0; ++ccpu) {
1199 globaldata_t rgd;
1200 caddr_t inp_ppcb;
1201 struct xtcpcb xt;
1202 int cpu_id;
1204 cpu_id = (origcpu + ccpu) % ncpus;
1205 if ((smp_active_mask & (1 << cpu_id)) == 0)
1206 continue;
1207 rgd = globaldata_find(cpu_id);
1208 lwkt_setcpu_self(rgd);
1210 gencnt = tcbinfo[cpu_id].ipi_gencnt;
1211 n = tcbinfo[cpu_id].ipi_count;
1213 LIST_INSERT_HEAD(&tcbinfo[cpu_id].pcblisthead, marker, inp_list);
1214 i = 0;
1215 while ((inp = LIST_NEXT(marker, inp_list)) != NULL && i < n) {
1217 * process a snapshot of pcbs, ignoring placemarkers
1218 * and using our own to allow SYSCTL_OUT to block.
1220 LIST_REMOVE(marker, inp_list);
1221 LIST_INSERT_AFTER(inp, marker, inp_list);
1223 if (inp->inp_flags & INP_PLACEMARKER)
1224 continue;
1225 if (inp->inp_gencnt > gencnt)
1226 continue;
1227 if (prison_xinpcb(req->td, inp))
1228 continue;
1230 xt.xt_len = sizeof xt;
1231 bcopy(inp, &xt.xt_inp, sizeof *inp);
1232 inp_ppcb = inp->inp_ppcb;
1233 if (inp_ppcb != NULL)
1234 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
1235 else
1236 bzero(&xt.xt_tp, sizeof xt.xt_tp);
1237 if (inp->inp_socket)
1238 sotoxsocket(inp->inp_socket, &xt.xt_socket);
1239 if ((error = SYSCTL_OUT(req, &xt, sizeof xt)) != 0)
1240 break;
1241 ++i;
1243 LIST_REMOVE(marker, inp_list);
1244 if (error == 0 && i < n) {
1245 bzero(&xt, sizeof xt);
1246 xt.xt_len = sizeof xt;
1247 while (i < n) {
1248 error = SYSCTL_OUT(req, &xt, sizeof xt);
1249 if (error)
1250 break;
1251 ++i;
1257 * Make sure we are on the same cpu we were on originally, since
1258 * higher level callers expect this. Also don't pollute caches with
1259 * migrated userland data by (eventually) returning to userland
1260 * on a different cpu.
1262 lwkt_setcpu_self(globaldata_find(origcpu));
1263 kfree(marker, M_TEMP);
1264 return (error);
1267 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
1268 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
1270 static int
1271 tcp_getcred(SYSCTL_HANDLER_ARGS)
1273 struct sockaddr_in addrs[2];
1274 struct inpcb *inp;
1275 int cpu;
1276 int error;
1278 error = priv_check(req->td, PRIV_ROOT);
1279 if (error != 0)
1280 return (error);
1281 error = SYSCTL_IN(req, addrs, sizeof addrs);
1282 if (error != 0)
1283 return (error);
1284 crit_enter();
1285 cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port,
1286 addrs[0].sin_addr.s_addr, addrs[0].sin_port);
1287 inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr,
1288 addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
1289 if (inp == NULL || inp->inp_socket == NULL) {
1290 error = ENOENT;
1291 goto out;
1293 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
1294 out:
1295 crit_exit();
1296 return (error);
1299 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW),
1300 0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection");
1302 #ifdef INET6
1303 static int
1304 tcp6_getcred(SYSCTL_HANDLER_ARGS)
1306 struct sockaddr_in6 addrs[2];
1307 struct inpcb *inp;
1308 int error;
1309 boolean_t mapped = FALSE;
1311 error = priv_check(req->td, PRIV_ROOT);
1312 if (error != 0)
1313 return (error);
1314 error = SYSCTL_IN(req, addrs, sizeof addrs);
1315 if (error != 0)
1316 return (error);
1317 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
1318 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
1319 mapped = TRUE;
1320 else
1321 return (EINVAL);
1323 crit_enter();
1324 if (mapped) {
1325 inp = in_pcblookup_hash(&tcbinfo[0],
1326 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
1327 addrs[1].sin6_port,
1328 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
1329 addrs[0].sin6_port,
1330 0, NULL);
1331 } else {
1332 inp = in6_pcblookup_hash(&tcbinfo[0],
1333 &addrs[1].sin6_addr, addrs[1].sin6_port,
1334 &addrs[0].sin6_addr, addrs[0].sin6_port,
1335 0, NULL);
1337 if (inp == NULL || inp->inp_socket == NULL) {
1338 error = ENOENT;
1339 goto out;
1341 error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
1342 out:
1343 crit_exit();
1344 return (error);
1347 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, (CTLTYPE_OPAQUE | CTLFLAG_RW),
1348 0, 0,
1349 tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection");
1350 #endif
1352 struct netmsg_tcp_notify {
1353 struct netmsg nm_nmsg;
1354 void (*nm_notify)(struct inpcb *, int);
1355 struct in_addr nm_faddr;
1356 int nm_arg;
1359 static void
1360 tcp_notifyall_oncpu(struct netmsg *netmsg)
1362 struct netmsg_tcp_notify *nmsg = (struct netmsg_tcp_notify *)netmsg;
1363 int nextcpu;
1365 in_pcbnotifyall(&tcbinfo[mycpuid].pcblisthead, nmsg->nm_faddr,
1366 nmsg->nm_arg, nmsg->nm_notify);
1368 nextcpu = mycpuid + 1;
1369 if (nextcpu < ncpus2)
1370 lwkt_forwardmsg(tcp_cport(nextcpu), &netmsg->nm_lmsg);
1371 else
1372 lwkt_replymsg(&netmsg->nm_lmsg, 0);
1375 void
1376 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
1378 struct ip *ip = vip;
1379 struct tcphdr *th;
1380 struct in_addr faddr;
1381 struct inpcb *inp;
1382 struct tcpcb *tp;
1383 void (*notify)(struct inpcb *, int) = tcp_notify;
1384 tcp_seq icmpseq;
1385 int arg, cpu;
1387 if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0) {
1388 return;
1391 faddr = ((struct sockaddr_in *)sa)->sin_addr;
1392 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
1393 return;
1395 arg = inetctlerrmap[cmd];
1396 if (cmd == PRC_QUENCH) {
1397 notify = tcp_quench;
1398 } else if (icmp_may_rst &&
1399 (cmd == PRC_UNREACH_ADMIN_PROHIB ||
1400 cmd == PRC_UNREACH_PORT ||
1401 cmd == PRC_TIMXCEED_INTRANS) &&
1402 ip != NULL) {
1403 notify = tcp_drop_syn_sent;
1404 } else if (cmd == PRC_MSGSIZE) {
1405 struct icmp *icmp = (struct icmp *)
1406 ((caddr_t)ip - offsetof(struct icmp, icmp_ip));
1408 arg = ntohs(icmp->icmp_nextmtu);
1409 notify = tcp_mtudisc;
1410 } else if (PRC_IS_REDIRECT(cmd)) {
1411 ip = NULL;
1412 notify = in_rtchange;
1413 } else if (cmd == PRC_HOSTDEAD) {
1414 ip = NULL;
1417 if (ip != NULL) {
1418 crit_enter();
1419 th = (struct tcphdr *)((caddr_t)ip +
1420 (IP_VHL_HL(ip->ip_vhl) << 2));
1421 cpu = tcp_addrcpu(faddr.s_addr, th->th_dport,
1422 ip->ip_src.s_addr, th->th_sport);
1423 inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport,
1424 ip->ip_src, th->th_sport, 0, NULL);
1425 if ((inp != NULL) && (inp->inp_socket != NULL)) {
1426 icmpseq = htonl(th->th_seq);
1427 tp = intotcpcb(inp);
1428 if (SEQ_GEQ(icmpseq, tp->snd_una) &&
1429 SEQ_LT(icmpseq, tp->snd_max))
1430 (*notify)(inp, arg);
1431 } else {
1432 struct in_conninfo inc;
1434 inc.inc_fport = th->th_dport;
1435 inc.inc_lport = th->th_sport;
1436 inc.inc_faddr = faddr;
1437 inc.inc_laddr = ip->ip_src;
1438 #ifdef INET6
1439 inc.inc_isipv6 = 0;
1440 #endif
1441 syncache_unreach(&inc, th);
1443 crit_exit();
1444 } else {
1445 struct netmsg_tcp_notify nmsg;
1447 KKASSERT(&curthread->td_msgport == cpu_portfn(0));
1448 netmsg_init(&nmsg.nm_nmsg, &curthread->td_msgport, 0,
1449 tcp_notifyall_oncpu);
1450 nmsg.nm_faddr = faddr;
1451 nmsg.nm_arg = arg;
1452 nmsg.nm_notify = notify;
1454 lwkt_domsg(tcp_cport(0), &nmsg.nm_nmsg.nm_lmsg, 0);
1458 #ifdef INET6
1459 void
1460 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
1462 struct tcphdr th;
1463 void (*notify) (struct inpcb *, int) = tcp_notify;
1464 struct ip6_hdr *ip6;
1465 struct mbuf *m;
1466 struct ip6ctlparam *ip6cp = NULL;
1467 const struct sockaddr_in6 *sa6_src = NULL;
1468 int off;
1469 struct tcp_portonly {
1470 u_int16_t th_sport;
1471 u_int16_t th_dport;
1472 } *thp;
1473 int arg;
1475 if (sa->sa_family != AF_INET6 ||
1476 sa->sa_len != sizeof(struct sockaddr_in6))
1477 return;
1479 arg = 0;
1480 if (cmd == PRC_QUENCH)
1481 notify = tcp_quench;
1482 else if (cmd == PRC_MSGSIZE) {
1483 struct ip6ctlparam *ip6cp = d;
1484 struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
1486 arg = ntohl(icmp6->icmp6_mtu);
1487 notify = tcp_mtudisc;
1488 } else if (!PRC_IS_REDIRECT(cmd) &&
1489 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0)) {
1490 return;
1493 /* if the parameter is from icmp6, decode it. */
1494 if (d != NULL) {
1495 ip6cp = (struct ip6ctlparam *)d;
1496 m = ip6cp->ip6c_m;
1497 ip6 = ip6cp->ip6c_ip6;
1498 off = ip6cp->ip6c_off;
1499 sa6_src = ip6cp->ip6c_src;
1500 } else {
1501 m = NULL;
1502 ip6 = NULL;
1503 off = 0; /* fool gcc */
1504 sa6_src = &sa6_any;
1507 if (ip6 != NULL) {
1508 struct in_conninfo inc;
1510 * XXX: We assume that when IPV6 is non NULL,
1511 * M and OFF are valid.
1514 /* check if we can safely examine src and dst ports */
1515 if (m->m_pkthdr.len < off + sizeof *thp)
1516 return;
1518 bzero(&th, sizeof th);
1519 m_copydata(m, off, sizeof *thp, (caddr_t)&th);
1521 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, th.th_dport,
1522 (struct sockaddr *)ip6cp->ip6c_src,
1523 th.th_sport, cmd, arg, notify);
1525 inc.inc_fport = th.th_dport;
1526 inc.inc_lport = th.th_sport;
1527 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
1528 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
1529 inc.inc_isipv6 = 1;
1530 syncache_unreach(&inc, &th);
1531 } else
1532 in6_pcbnotify(&tcbinfo[0].pcblisthead, sa, 0,
1533 (const struct sockaddr *)sa6_src, 0, cmd, arg, notify);
1535 #endif
1538 * Following is where TCP initial sequence number generation occurs.
1540 * There are two places where we must use initial sequence numbers:
1541 * 1. In SYN-ACK packets.
1542 * 2. In SYN packets.
1544 * All ISNs for SYN-ACK packets are generated by the syncache. See
1545 * tcp_syncache.c for details.
1547 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
1548 * depends on this property. In addition, these ISNs should be
1549 * unguessable so as to prevent connection hijacking. To satisfy
1550 * the requirements of this situation, the algorithm outlined in
1551 * RFC 1948 is used to generate sequence numbers.
1553 * Implementation details:
1555 * Time is based off the system timer, and is corrected so that it
1556 * increases by one megabyte per second. This allows for proper
1557 * recycling on high speed LANs while still leaving over an hour
1558 * before rollover.
1560 * net.inet.tcp.isn_reseed_interval controls the number of seconds
1561 * between seeding of isn_secret. This is normally set to zero,
1562 * as reseeding should not be necessary.
1566 #define ISN_BYTES_PER_SECOND 1048576
1568 u_char isn_secret[32];
1569 int isn_last_reseed;
1570 MD5_CTX isn_ctx;
1572 tcp_seq
1573 tcp_new_isn(struct tcpcb *tp)
1575 u_int32_t md5_buffer[4];
1576 tcp_seq new_isn;
1578 /* Seed if this is the first use, reseed if requested. */
1579 if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) &&
1580 (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz)
1581 < (u_int)ticks))) {
1582 read_random_unlimited(&isn_secret, sizeof isn_secret);
1583 isn_last_reseed = ticks;
1586 /* Compute the md5 hash and return the ISN. */
1587 MD5Init(&isn_ctx);
1588 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_fport, sizeof(u_short));
1589 MD5Update(&isn_ctx, (u_char *)&tp->t_inpcb->inp_lport, sizeof(u_short));
1590 #ifdef INET6
1591 if (tp->t_inpcb->inp_vflag & INP_IPV6) {
1592 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
1593 sizeof(struct in6_addr));
1594 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
1595 sizeof(struct in6_addr));
1596 } else
1597 #endif
1599 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
1600 sizeof(struct in_addr));
1601 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
1602 sizeof(struct in_addr));
1604 MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret));
1605 MD5Final((u_char *) &md5_buffer, &isn_ctx);
1606 new_isn = (tcp_seq) md5_buffer[0];
1607 new_isn += ticks * (ISN_BYTES_PER_SECOND / hz);
1608 return (new_isn);
1612 * When a source quench is received, close congestion window
1613 * to one segment. We will gradually open it again as we proceed.
1615 void
1616 tcp_quench(struct inpcb *inp, int error)
1618 struct tcpcb *tp = intotcpcb(inp);
1620 if (tp != NULL) {
1621 tp->snd_cwnd = tp->t_maxseg;
1622 tp->snd_wacked = 0;
1627 * When a specific ICMP unreachable message is received and the
1628 * connection state is SYN-SENT, drop the connection. This behavior
1629 * is controlled by the icmp_may_rst sysctl.
1631 void
1632 tcp_drop_syn_sent(struct inpcb *inp, int error)
1634 struct tcpcb *tp = intotcpcb(inp);
1636 if ((tp != NULL) && (tp->t_state == TCPS_SYN_SENT))
1637 tcp_drop(tp, error);
1641 * When a `need fragmentation' ICMP is received, update our idea of the MSS
1642 * based on the new value in the route. Also nudge TCP to send something,
1643 * since we know the packet we just sent was dropped.
1644 * This duplicates some code in the tcp_mss() function in tcp_input.c.
1646 void
1647 tcp_mtudisc(struct inpcb *inp, int mtu)
1649 struct tcpcb *tp = intotcpcb(inp);
1650 struct rtentry *rt;
1651 struct socket *so = inp->inp_socket;
1652 int maxopd, mss;
1653 #ifdef INET6
1654 boolean_t isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0);
1655 #else
1656 const boolean_t isipv6 = FALSE;
1657 #endif
1659 if (tp == NULL)
1660 return;
1663 * If no MTU is provided in the ICMP message, use the
1664 * next lower likely value, as specified in RFC 1191.
1666 if (mtu == 0) {
1667 int oldmtu;
1669 oldmtu = tp->t_maxopd +
1670 (isipv6 ?
1671 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1672 sizeof(struct tcpiphdr));
1673 mtu = ip_next_mtu(oldmtu, 0);
1676 if (isipv6)
1677 rt = tcp_rtlookup6(&inp->inp_inc);
1678 else
1679 rt = tcp_rtlookup(&inp->inp_inc);
1680 if (rt != NULL) {
1681 struct rmxp_tao *taop = rmx_taop(rt->rt_rmx);
1683 if (rt->rt_rmx.rmx_mtu != 0 && rt->rt_rmx.rmx_mtu < mtu)
1684 mtu = rt->rt_rmx.rmx_mtu;
1686 maxopd = mtu -
1687 (isipv6 ?
1688 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1689 sizeof(struct tcpiphdr));
1692 * XXX - The following conditional probably violates the TCP
1693 * spec. The problem is that, since we don't know the
1694 * other end's MSS, we are supposed to use a conservative
1695 * default. But, if we do that, then MTU discovery will
1696 * never actually take place, because the conservative
1697 * default is much less than the MTUs typically seen
1698 * on the Internet today. For the moment, we'll sweep
1699 * this under the carpet.
1701 * The conservative default might not actually be a problem
1702 * if the only case this occurs is when sending an initial
1703 * SYN with options and data to a host we've never talked
1704 * to before. Then, they will reply with an MSS value which
1705 * will get recorded and the new parameters should get
1706 * recomputed. For Further Study.
1708 if (taop->tao_mssopt != 0 && taop->tao_mssopt < maxopd)
1709 maxopd = taop->tao_mssopt;
1710 } else
1711 maxopd = mtu -
1712 (isipv6 ?
1713 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
1714 sizeof(struct tcpiphdr));
1716 if (tp->t_maxopd <= maxopd)
1717 return;
1718 tp->t_maxopd = maxopd;
1720 mss = maxopd;
1721 if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP | TF_NOOPT)) ==
1722 (TF_REQ_TSTMP | TF_RCVD_TSTMP))
1723 mss -= TCPOLEN_TSTAMP_APPA;
1725 if ((tp->t_flags & (TF_REQ_CC | TF_RCVD_CC | TF_NOOPT)) ==
1726 (TF_REQ_CC | TF_RCVD_CC))
1727 mss -= TCPOLEN_CC_APPA;
1729 /* round down to multiple of MCLBYTES */
1730 #if (MCLBYTES & (MCLBYTES - 1)) == 0 /* test if MCLBYTES power of 2 */
1731 if (mss > MCLBYTES)
1732 mss &= ~(MCLBYTES - 1);
1733 #else
1734 if (mss > MCLBYTES)
1735 mss = (mss / MCLBYTES) * MCLBYTES;
1736 #endif
1738 if (so->so_snd.ssb_hiwat < mss)
1739 mss = so->so_snd.ssb_hiwat;
1741 tp->t_maxseg = mss;
1742 tp->t_rtttime = 0;
1743 tp->snd_nxt = tp->snd_una;
1744 tcp_output(tp);
1745 tcpstat.tcps_mturesent++;
1749 * Look-up the routing entry to the peer of this inpcb. If no route
1750 * is found and it cannot be allocated the return NULL. This routine
1751 * is called by TCP routines that access the rmx structure and by tcp_mss
1752 * to get the interface MTU.
1754 struct rtentry *
1755 tcp_rtlookup(struct in_conninfo *inc)
1757 struct route *ro = &inc->inc_route;
1759 if (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP)) {
1760 /* No route yet, so try to acquire one */
1761 if (inc->inc_faddr.s_addr != INADDR_ANY) {
1763 * unused portions of the structure MUST be zero'd
1764 * out because rtalloc() treats it as opaque data
1766 bzero(&ro->ro_dst, sizeof(struct sockaddr_in));
1767 ro->ro_dst.sa_family = AF_INET;
1768 ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
1769 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
1770 inc->inc_faddr;
1771 rtalloc(ro);
1774 return (ro->ro_rt);
1777 #ifdef INET6
1778 struct rtentry *
1779 tcp_rtlookup6(struct in_conninfo *inc)
1781 struct route_in6 *ro6 = &inc->inc6_route;
1783 if (ro6->ro_rt == NULL || !(ro6->ro_rt->rt_flags & RTF_UP)) {
1784 /* No route yet, so try to acquire one */
1785 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
1787 * unused portions of the structure MUST be zero'd
1788 * out because rtalloc() treats it as opaque data
1790 bzero(&ro6->ro_dst, sizeof(struct sockaddr_in6));
1791 ro6->ro_dst.sin6_family = AF_INET6;
1792 ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6);
1793 ro6->ro_dst.sin6_addr = inc->inc6_faddr;
1794 rtalloc((struct route *)ro6);
1797 return (ro6->ro_rt);
1799 #endif
1801 #ifdef IPSEC
1802 /* compute ESP/AH header size for TCP, including outer IP header. */
1803 size_t
1804 ipsec_hdrsiz_tcp(struct tcpcb *tp)
1806 struct inpcb *inp;
1807 struct mbuf *m;
1808 size_t hdrsiz;
1809 struct ip *ip;
1810 struct tcphdr *th;
1812 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
1813 return (0);
1814 MGETHDR(m, MB_DONTWAIT, MT_DATA);
1815 if (!m)
1816 return (0);
1818 #ifdef INET6
1819 if (inp->inp_vflag & INP_IPV6) {
1820 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1822 th = (struct tcphdr *)(ip6 + 1);
1823 m->m_pkthdr.len = m->m_len =
1824 sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
1825 tcp_fillheaders(tp, ip6, th);
1826 hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1827 } else
1828 #endif
1830 ip = mtod(m, struct ip *);
1831 th = (struct tcphdr *)(ip + 1);
1832 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
1833 tcp_fillheaders(tp, ip, th);
1834 hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
1837 m_free(m);
1838 return (hdrsiz);
1840 #endif
1843 * Return a pointer to the cached information about the remote host.
1844 * The cached information is stored in the protocol specific part of
1845 * the route metrics.
1847 struct rmxp_tao *
1848 tcp_gettaocache(struct in_conninfo *inc)
1850 struct rtentry *rt;
1852 #ifdef INET6
1853 if (inc->inc_isipv6)
1854 rt = tcp_rtlookup6(inc);
1855 else
1856 #endif
1857 rt = tcp_rtlookup(inc);
1859 /* Make sure this is a host route and is up. */
1860 if (rt == NULL ||
1861 (rt->rt_flags & (RTF_UP | RTF_HOST)) != (RTF_UP | RTF_HOST))
1862 return (NULL);
1864 return (rmx_taop(rt->rt_rmx));
1868 * Clear all the TAO cache entries, called from tcp_init.
1870 * XXX
1871 * This routine is just an empty one, because we assume that the routing
1872 * routing tables are initialized at the same time when TCP, so there is
1873 * nothing in the cache left over.
1875 static void
1876 tcp_cleartaocache(void)
1881 * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
1883 * This code attempts to calculate the bandwidth-delay product as a
1884 * means of determining the optimal window size to maximize bandwidth,
1885 * minimize RTT, and avoid the over-allocation of buffers on interfaces and
1886 * routers. This code also does a fairly good job keeping RTTs in check
1887 * across slow links like modems. We implement an algorithm which is very
1888 * similar (but not meant to be) TCP/Vegas. The code operates on the
1889 * transmitter side of a TCP connection and so only effects the transmit
1890 * side of the connection.
1892 * BACKGROUND: TCP makes no provision for the management of buffer space
1893 * at the end points or at the intermediate routers and switches. A TCP
1894 * stream, whether using NewReno or not, will eventually buffer as
1895 * many packets as it is able and the only reason this typically works is
1896 * due to the fairly small default buffers made available for a connection
1897 * (typicaly 16K or 32K). As machines use larger windows and/or window
1898 * scaling it is now fairly easy for even a single TCP connection to blow-out
1899 * all available buffer space not only on the local interface, but on
1900 * intermediate routers and switches as well. NewReno makes a misguided
1901 * attempt to 'solve' this problem by waiting for an actual failure to occur,
1902 * then backing off, then steadily increasing the window again until another
1903 * failure occurs, ad-infinitum. This results in terrible oscillation that
1904 * is only made worse as network loads increase and the idea of intentionally
1905 * blowing out network buffers is, frankly, a terrible way to manage network
1906 * resources.
1908 * It is far better to limit the transmit window prior to the failure
1909 * condition being achieved. There are two general ways to do this: First
1910 * you can 'scan' through different transmit window sizes and locate the
1911 * point where the RTT stops increasing, indicating that you have filled the
1912 * pipe, then scan backwards until you note that RTT stops decreasing, then
1913 * repeat ad-infinitum. This method works in principle but has severe
1914 * implementation issues due to RTT variances, timer granularity, and
1915 * instability in the algorithm which can lead to many false positives and
1916 * create oscillations as well as interact badly with other TCP streams
1917 * implementing the same algorithm.
1919 * The second method is to limit the window to the bandwidth delay product
1920 * of the link. This is the method we implement. RTT variances and our
1921 * own manipulation of the congestion window, bwnd, can potentially
1922 * destabilize the algorithm. For this reason we have to stabilize the
1923 * elements used to calculate the window. We do this by using the minimum
1924 * observed RTT, the long term average of the observed bandwidth, and
1925 * by adding two segments worth of slop. It isn't perfect but it is able
1926 * to react to changing conditions and gives us a very stable basis on
1927 * which to extend the algorithm.
1929 void
1930 tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq)
1932 u_long bw;
1933 u_long bwnd;
1934 int save_ticks;
1935 int delta_ticks;
1938 * If inflight_enable is disabled in the middle of a tcp connection,
1939 * make sure snd_bwnd is effectively disabled.
1941 if (!tcp_inflight_enable) {
1942 tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1943 tp->snd_bandwidth = 0;
1944 return;
1948 * Validate the delta time. If a connection is new or has been idle
1949 * a long time we have to reset the bandwidth calculator.
1951 save_ticks = ticks;
1952 delta_ticks = save_ticks - tp->t_bw_rtttime;
1953 if (tp->t_bw_rtttime == 0 || delta_ticks < 0 || delta_ticks > hz * 10) {
1954 tp->t_bw_rtttime = ticks;
1955 tp->t_bw_rtseq = ack_seq;
1956 if (tp->snd_bandwidth == 0)
1957 tp->snd_bandwidth = tcp_inflight_min;
1958 return;
1960 if (delta_ticks == 0)
1961 return;
1964 * Sanity check, plus ignore pure window update acks.
1966 if ((int)(ack_seq - tp->t_bw_rtseq) <= 0)
1967 return;
1970 * Figure out the bandwidth. Due to the tick granularity this
1971 * is a very rough number and it MUST be averaged over a fairly
1972 * long period of time. XXX we need to take into account a link
1973 * that is not using all available bandwidth, but for now our
1974 * slop will ramp us up if this case occurs and the bandwidth later
1975 * increases.
1977 bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / delta_ticks;
1978 tp->t_bw_rtttime = save_ticks;
1979 tp->t_bw_rtseq = ack_seq;
1980 bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4;
1982 tp->snd_bandwidth = bw;
1985 * Calculate the semi-static bandwidth delay product, plus two maximal
1986 * segments. The additional slop puts us squarely in the sweet
1987 * spot and also handles the bandwidth run-up case. Without the
1988 * slop we could be locking ourselves into a lower bandwidth.
1990 * Situations Handled:
1991 * (1) Prevents over-queueing of packets on LANs, especially on
1992 * high speed LANs, allowing larger TCP buffers to be
1993 * specified, and also does a good job preventing
1994 * over-queueing of packets over choke points like modems
1995 * (at least for the transmit side).
1997 * (2) Is able to handle changing network loads (bandwidth
1998 * drops so bwnd drops, bandwidth increases so bwnd
1999 * increases).
2001 * (3) Theoretically should stabilize in the face of multiple
2002 * connections implementing the same algorithm (this may need
2003 * a little work).
2005 * (4) Stability value (defaults to 20 = 2 maximal packets) can
2006 * be adjusted with a sysctl but typically only needs to be on
2007 * very slow connections. A value no smaller then 5 should
2008 * be used, but only reduce this default if you have no other
2009 * choice.
2012 #define USERTT ((tp->t_srtt + tp->t_rttbest) / 2)
2013 bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) +
2014 tcp_inflight_stab * (int)tp->t_maxseg / 10;
2015 #undef USERTT
2017 if (tcp_inflight_debug > 0) {
2018 static int ltime;
2019 if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) {
2020 ltime = ticks;
2021 kprintf("%p bw %ld rttbest %d srtt %d bwnd %ld\n",
2022 tp, bw, tp->t_rttbest, tp->t_srtt, bwnd);
2025 if ((long)bwnd < tcp_inflight_min)
2026 bwnd = tcp_inflight_min;
2027 if (bwnd > tcp_inflight_max)
2028 bwnd = tcp_inflight_max;
2029 if ((long)bwnd < tp->t_maxseg * 2)
2030 bwnd = tp->t_maxseg * 2;
2031 tp->snd_bwnd = bwnd;