1 /* $NetBSD: tcp_subr.c,v 1.187.2.3 2005/05/06 08:39:52 tron Exp $ */
2
3 /*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*-
33 * Copyright (c) 1997, 1998, 2000, 2001 The NetBSD Foundation, Inc.
34 * All rights reserved.
35 *
36 * This code is derived from software contributed to The NetBSD Foundation
37 * by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation
38 * Facility, NASA Ames Research Center.
39 *
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
42 * are met:
43 * 1. Redistributions of source code must retain the above copyright
44 * notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 * notice, this list of conditions and the following disclaimer in the
47 * documentation and/or other materials provided with the distribution.
48 * 3. All advertising materials mentioning features or use of this software
49 * must display the following acknowledgement:
50 * This product includes software developed by the NetBSD
51 * Foundation, Inc. and its contributors.
52 * 4. Neither the name of The NetBSD Foundation nor the names of its
53 * contributors may be used to endorse or promote products derived
54 * from this software without specific prior written permission.
55 *
56 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
57 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
58 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
59 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
60 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
61 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
62 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
63 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
64 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
65 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
66 * POSSIBILITY OF SUCH DAMAGE.
67 */
68
69 /*
70 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
71 * The Regents of the University of California. All rights reserved.
72 *
73 * Redistribution and use in source and binary forms, with or without
74 * modification, are permitted provided that the following conditions
75 * are met:
76 * 1. Redistributions of source code must retain the above copyright
77 * notice, this list of conditions and the following disclaimer.
78 * 2. Redistributions in binary form must reproduce the above copyright
79 * notice, this list of conditions and the following disclaimer in the
80 * documentation and/or other materials provided with the distribution.
81 * 3. Neither the name of the University nor the names of its contributors
82 * may be used to endorse or promote products derived from this software
83 * without specific prior written permission.
84 *
85 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
86 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
87 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
88 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
89 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
90 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
91 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
92 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
93 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
94 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
95 * SUCH DAMAGE.
96 *
97 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
98 */
99
100 #include <sys/cdefs.h>
101 __KERNEL_RCSID(0, "$NetBSD: tcp_subr.c,v 1.187.2.3 2005/05/06 08:39:52 tron Exp $");
102
103 #include "opt_inet.h"
104 #include "opt_ipsec.h"
105 #include "opt_tcp_compat_42.h"
106 #include "opt_inet_csum.h"
107 #include "opt_mbuftrace.h"
108 #include "rnd.h"
109
110 #include <sys/param.h>
111 #include <sys/proc.h>
112 #include <sys/systm.h>
113 #include <sys/malloc.h>
114 #include <sys/mbuf.h>
115 #include <sys/socket.h>
116 #include <sys/socketvar.h>
117 #include <sys/protosw.h>
118 #include <sys/errno.h>
119 #include <sys/kernel.h>
120 #include <sys/pool.h>
121 #if NRND > 0
122 #include <sys/md5.h>
123 #include <sys/rnd.h>
124 #endif
125
126 #include <net/route.h>
127 #include <net/if.h>
128
129 #include <netinet/in.h>
130 #include <netinet/in_systm.h>
131 #include <netinet/ip.h>
132 #include <netinet/in_pcb.h>
133 #include <netinet/ip_var.h>
134 #include <netinet/ip_icmp.h>
135
136 #ifdef INET6
137 #ifndef INET
138 #include <netinet/in.h>
139 #endif
140 #include <netinet/ip6.h>
141 #include <netinet6/in6_pcb.h>
142 #include <netinet6/ip6_var.h>
143 #include <netinet6/in6_var.h>
144 #include <netinet6/ip6protosw.h>
145 #include <netinet/icmp6.h>
146 #include <netinet6/nd6.h>
147 #endif
148
149 #include <netinet/tcp.h>
150 #include <netinet/tcp_fsm.h>
151 #include <netinet/tcp_seq.h>
152 #include <netinet/tcp_timer.h>
153 #include <netinet/tcp_var.h>
154 #include <netinet/tcpip.h>
155
156 #ifdef IPSEC
157 #include <netinet6/ipsec.h>
158 #include <netkey/key.h>
159 #endif /*IPSEC*/
160
161 #ifdef FAST_IPSEC
162 #include <netipsec/ipsec.h>
163 #include <netipsec/xform.h>
164 #ifdef INET6
165 #include <netipsec/ipsec6.h>
166 #endif
167 #include <netipsec/key.h>
168 #endif /* FAST_IPSEC*/
169
170
171 struct inpcbtable tcbtable; /* head of queue of active tcpcb's */
172 struct tcpstat tcpstat; /* tcp statistics */
173 u_int32_t tcp_now; /* for RFC 1323 timestamps */
174
175 /* patchable/settable parameters for tcp */
176 int tcp_mssdflt = TCP_MSS;
177 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
178 int tcp_do_rfc1323 = 1; /* window scaling / timestamps (obsolete) */
179 #if NRND > 0
180 int tcp_do_rfc1948 = 0; /* ISS by cryptographic hash */
181 #endif
182 int tcp_do_sack = 1; /* selective acknowledgement */
183 int tcp_do_win_scale = 1; /* RFC1323 window scaling */
184 int tcp_do_timestamps = 1; /* RFC1323 timestamps */
185 int tcp_do_newreno = 1; /* Use the New Reno algorithms */
186 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */
187 #ifndef TCP_INIT_WIN
188 #define TCP_INIT_WIN 0 /* initial slow start window */
189 #endif
190 #ifndef TCP_INIT_WIN_LOCAL
191 #define TCP_INIT_WIN_LOCAL 4 /* initial slow start window for local nets */
192 #endif
193 int tcp_init_win = TCP_INIT_WIN;
194 int tcp_init_win_local = TCP_INIT_WIN_LOCAL;
195 int tcp_mss_ifmtu = 0;
196 #ifdef TCP_COMPAT_42
197 int tcp_compat_42 = 1;
198 #else
199 int tcp_compat_42 = 0;
200 #endif
201 int tcp_rst_ppslim = 100; /* 100pps */
202 int tcp_ackdrop_ppslim = 100; /* 100pps */
203 int tcp_sack_tp_maxholes = 32;
204 int tcp_sack_globalmaxholes = 1024;
205 int tcp_sack_globalholes = 0;
206
207
208 /* tcb hash */
209 #ifndef TCBHASHSIZE
210 #define TCBHASHSIZE 128
211 #endif
212 int tcbhashsize = TCBHASHSIZE;
213
214 /* syn hash parameters */
215 #define TCP_SYN_HASH_SIZE 293
216 #define TCP_SYN_BUCKET_SIZE 35
217 int tcp_syn_cache_size = TCP_SYN_HASH_SIZE;
218 int tcp_syn_cache_limit = TCP_SYN_HASH_SIZE*TCP_SYN_BUCKET_SIZE;
219 int tcp_syn_bucket_limit = 3*TCP_SYN_BUCKET_SIZE;
220 struct syn_cache_head tcp_syn_cache[TCP_SYN_HASH_SIZE];
221
222 int tcp_freeq(struct tcpcb *);
223
224 #ifdef INET
225 void tcp_mtudisc_callback(struct in_addr);
226 #endif
227 #ifdef INET6
228 void tcp6_mtudisc_callback(struct in6_addr *);
229 #endif
230
231 void tcp_mtudisc(struct inpcb *, int);
232 #ifdef INET6
233 void tcp6_mtudisc(struct in6pcb *, int);
234 #endif
235
236 POOL_INIT(tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl", NULL);
237
238 #ifdef TCP_CSUM_COUNTERS
239 #include <sys/device.h>
240
241 struct evcnt tcp_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
242 NULL, "tcp", "hwcsum bad");
243 struct evcnt tcp_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
244 NULL, "tcp", "hwcsum ok");
245 struct evcnt tcp_hwcsum_data = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
246 NULL, "tcp", "hwcsum data");
247 struct evcnt tcp_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
248 NULL, "tcp", "swcsum");
249
250 EVCNT_ATTACH_STATIC(tcp_hwcsum_bad);
251 EVCNT_ATTACH_STATIC(tcp_hwcsum_ok);
252 EVCNT_ATTACH_STATIC(tcp_hwcsum_data);
253 EVCNT_ATTACH_STATIC(tcp_swcsum);
254 #endif /* TCP_CSUM_COUNTERS */
255
256
257 #ifdef TCP_OUTPUT_COUNTERS
258 #include <sys/device.h>
259
260 struct evcnt tcp_output_bigheader = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
261 NULL, "tcp", "output big header");
262 struct evcnt tcp_output_predict_hit = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
263 NULL, "tcp", "output predict hit");
264 struct evcnt tcp_output_predict_miss = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
265 NULL, "tcp", "output predict miss");
266 struct evcnt tcp_output_copysmall = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
267 NULL, "tcp", "output copy small");
268 struct evcnt tcp_output_copybig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
269 NULL, "tcp", "output copy big");
270 struct evcnt tcp_output_refbig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
271 NULL, "tcp", "output reference big");
272
273 EVCNT_ATTACH_STATIC(tcp_output_bigheader);
274 EVCNT_ATTACH_STATIC(tcp_output_predict_hit);
275 EVCNT_ATTACH_STATIC(tcp_output_predict_miss);
276 EVCNT_ATTACH_STATIC(tcp_output_copysmall);
277 EVCNT_ATTACH_STATIC(tcp_output_copybig);
278 EVCNT_ATTACH_STATIC(tcp_output_refbig);
279
280 #endif /* TCP_OUTPUT_COUNTERS */
281
282 #ifdef TCP_REASS_COUNTERS
283 #include <sys/device.h>
284
285 struct evcnt tcp_reass_ = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
286 NULL, "tcp_reass", "calls");
287 struct evcnt tcp_reass_empty = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
288 &tcp_reass_, "tcp_reass", "insert into empty queue");
289 struct evcnt tcp_reass_iteration[8] = {
290 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", ">7 iterations"),
291 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "1 iteration"),
292 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "2 iterations"),
293 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "3 iterations"),
294 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "4 iterations"),
295 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "5 iterations"),
296 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "6 iterations"),
297 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "7 iterations"),
298 };
299 struct evcnt tcp_reass_prependfirst = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
300 &tcp_reass_, "tcp_reass", "prepend to first");
301 struct evcnt tcp_reass_prepend = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
302 &tcp_reass_, "tcp_reass", "prepend");
303 struct evcnt tcp_reass_insert = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
304 &tcp_reass_, "tcp_reass", "insert");
305 struct evcnt tcp_reass_inserttail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
306 &tcp_reass_, "tcp_reass", "insert at tail");
307 struct evcnt tcp_reass_append = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
308 &tcp_reass_, "tcp_reass", "append");
309 struct evcnt tcp_reass_appendtail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
310 &tcp_reass_, "tcp_reass", "append to tail fragment");
311 struct evcnt tcp_reass_overlaptail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
312 &tcp_reass_, "tcp_reass", "overlap at end");
313 struct evcnt tcp_reass_overlapfront = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
314 &tcp_reass_, "tcp_reass", "overlap at start");
315 struct evcnt tcp_reass_segdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
316 &tcp_reass_, "tcp_reass", "duplicate segment");
317 struct evcnt tcp_reass_fragdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
318 &tcp_reass_, "tcp_reass", "duplicate fragment");
319
320 EVCNT_ATTACH_STATIC(tcp_reass_);
321 EVCNT_ATTACH_STATIC(tcp_reass_empty);
322 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 0);
323 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 1);
324 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 2);
325 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 3);
326 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 4);
327 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 5);
328 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 6);
329 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 7);
330 EVCNT_ATTACH_STATIC(tcp_reass_prependfirst);
331 EVCNT_ATTACH_STATIC(tcp_reass_prepend);
332 EVCNT_ATTACH_STATIC(tcp_reass_insert);
333 EVCNT_ATTACH_STATIC(tcp_reass_inserttail);
334 EVCNT_ATTACH_STATIC(tcp_reass_append);
335 EVCNT_ATTACH_STATIC(tcp_reass_appendtail);
336 EVCNT_ATTACH_STATIC(tcp_reass_overlaptail);
337 EVCNT_ATTACH_STATIC(tcp_reass_overlapfront);
338 EVCNT_ATTACH_STATIC(tcp_reass_segdup);
339 EVCNT_ATTACH_STATIC(tcp_reass_fragdup);
340
341 #endif /* TCP_REASS_COUNTERS */
342
343 #ifdef MBUFTRACE
344 struct mowner tcp_mowner = { "tcp" };
345 struct mowner tcp_rx_mowner = { "tcp", "rx" };
346 struct mowner tcp_tx_mowner = { "tcp", "tx" };
347 #endif
348
349 /*
350 * Tcp initialization
351 */
352 void
353 tcp_init(void)
354 {
355 int hlen;
356
357 /* Initialize the TCPCB template. */
358 tcp_tcpcb_template();
359
360 in_pcbinit(&tcbtable, tcbhashsize, tcbhashsize);
361
362 hlen = sizeof(struct ip) + sizeof(struct tcphdr);
363 #ifdef INET6
364 if (sizeof(struct ip) < sizeof(struct ip6_hdr))
365 hlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
366 #endif
367 if (max_protohdr < hlen)
368 max_protohdr = hlen;
369 if (max_linkhdr + hlen > MHLEN)
370 panic("tcp_init");
371
372 #ifdef INET
373 icmp_mtudisc_callback_register(tcp_mtudisc_callback);
374 #endif
375 #ifdef INET6
376 icmp6_mtudisc_callback_register(tcp6_mtudisc_callback);
377 #endif
378
379 /* Initialize timer state. */
380 tcp_timer_init();
381
382 /* Initialize the compressed state engine. */
383 syn_cache_init();
384
385 MOWNER_ATTACH(&tcp_tx_mowner);
386 MOWNER_ATTACH(&tcp_rx_mowner);
387 MOWNER_ATTACH(&tcp_mowner);
388 }
389
390 /*
391 * Create template to be used to send tcp packets on a connection.
392 * Call after host entry created, allocates an mbuf and fills
393 * in a skeletal tcp/ip header, minimizing the amount of work
394 * necessary when the connection is used.
395 */
396 struct mbuf *
397 tcp_template(struct tcpcb *tp)
398 {
399 struct inpcb *inp = tp->t_inpcb;
400 #ifdef INET6
401 struct in6pcb *in6p = tp->t_in6pcb;
402 #endif
403 struct tcphdr *n;
404 struct mbuf *m;
405 int hlen;
406
407 switch (tp->t_family) {
408 case AF_INET:
409 hlen = sizeof(struct ip);
410 if (inp)
411 break;
412 #ifdef INET6
413 if (in6p) {
414 /* mapped addr case */
415 if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_laddr)
416 && IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr))
417 break;
418 }
419 #endif
420 return NULL; /*EINVAL*/
421 #ifdef INET6
422 case AF_INET6:
423 hlen = sizeof(struct ip6_hdr);
424 if (in6p) {
425 /* more sainty check? */
426 break;
427 }
428 return NULL; /*EINVAL*/
429 #endif
430 default:
431 hlen = 0; /*pacify gcc*/
432 return NULL; /*EAFNOSUPPORT*/
433 }
434 #ifdef DIAGNOSTIC
435 if (hlen + sizeof(struct tcphdr) > MCLBYTES)
436 panic("mclbytes too small for t_template");
437 #endif
438 m = tp->t_template;
439 if (m && m->m_len == hlen + sizeof(struct tcphdr))
440 ;
441 else {
442 if (m)
443 m_freem(m);
444 m = tp->t_template = NULL;
445 MGETHDR(m, M_DONTWAIT, MT_HEADER);
446 if (m && hlen + sizeof(struct tcphdr) > MHLEN) {
447 MCLGET(m, M_DONTWAIT);
448 if ((m->m_flags & M_EXT) == 0) {
449 m_free(m);
450 m = NULL;
451 }
452 }
453 if (m == NULL)
454 return NULL;
455 MCLAIM(m, &tcp_mowner);
456 m->m_pkthdr.len = m->m_len = hlen + sizeof(struct tcphdr);
457 }
458
459 bzero(mtod(m, caddr_t), m->m_len);
460
461 n = (struct tcphdr *)(mtod(m, caddr_t) + hlen);
462
463 switch (tp->t_family) {
464 case AF_INET:
465 {
466 struct ipovly *ipov;
467 mtod(m, struct ip *)->ip_v = 4;
468 mtod(m, struct ip *)->ip_hl = hlen >> 2;
469 ipov = mtod(m, struct ipovly *);
470 ipov->ih_pr = IPPROTO_TCP;
471 ipov->ih_len = htons(sizeof(struct tcphdr));
472 if (inp) {
473 ipov->ih_src = inp->inp_laddr;
474 ipov->ih_dst = inp->inp_faddr;
475 }
476 #ifdef INET6
477 else if (in6p) {
478 /* mapped addr case */
479 bcopy(&in6p->in6p_laddr.s6_addr32[3], &ipov->ih_src,
480 sizeof(ipov->ih_src));
481 bcopy(&in6p->in6p_faddr.s6_addr32[3], &ipov->ih_dst,
482 sizeof(ipov->ih_dst));
483 }
484 #endif
485 /*
486 * Compute the pseudo-header portion of the checksum
487 * now. We incrementally add in the TCP option and
488 * payload lengths later, and then compute the TCP
489 * checksum right before the packet is sent off onto
490 * the wire.
491 */
492 n->th_sum = in_cksum_phdr(ipov->ih_src.s_addr,
493 ipov->ih_dst.s_addr,
494 htons(sizeof(struct tcphdr) + IPPROTO_TCP));
495 break;
496 }
497 #ifdef INET6
498 case AF_INET6:
499 {
500 struct ip6_hdr *ip6;
501 mtod(m, struct ip *)->ip_v = 6;
502 ip6 = mtod(m, struct ip6_hdr *);
503 ip6->ip6_nxt = IPPROTO_TCP;
504 ip6->ip6_plen = htons(sizeof(struct tcphdr));
505 ip6->ip6_src = in6p->in6p_laddr;
506 ip6->ip6_dst = in6p->in6p_faddr;
507 ip6->ip6_flow = in6p->in6p_flowinfo & IPV6_FLOWINFO_MASK;
508 if (ip6_auto_flowlabel) {
509 ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK;
510 ip6->ip6_flow |=
511 (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK);
512 }
513 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
514 ip6->ip6_vfc |= IPV6_VERSION;
515
516 /*
517 * Compute the pseudo-header portion of the checksum
518 * now. We incrementally add in the TCP option and
519 * payload lengths later, and then compute the TCP
520 * checksum right before the packet is sent off onto
521 * the wire.
522 */
523 n->th_sum = in6_cksum_phdr(&in6p->in6p_laddr,
524 &in6p->in6p_faddr, htonl(sizeof(struct tcphdr)),
525 htonl(IPPROTO_TCP));
526 break;
527 }
528 #endif
529 }
530 if (inp) {
531 n->th_sport = inp->inp_lport;
532 n->th_dport = inp->inp_fport;
533 }
534 #ifdef INET6
535 else if (in6p) {
536 n->th_sport = in6p->in6p_lport;
537 n->th_dport = in6p->in6p_fport;
538 }
539 #endif
540 n->th_seq = 0;
541 n->th_ack = 0;
542 n->th_x2 = 0;
543 n->th_off = 5;
544 n->th_flags = 0;
545 n->th_win = 0;
546 n->th_urp = 0;
547 return (m);
548 }
549
550 /*
551 * Send a single message to the TCP at address specified by
552 * the given TCP/IP header. If m == 0, then we make a copy
553 * of the tcpiphdr at ti and send directly to the addressed host.
554 * This is used to force keep alive messages out using the TCP
555 * template for a connection tp->t_template. If flags are given
556 * then we send a message back to the TCP which originated the
557 * segment ti, and discard the mbuf containing it and any other
558 * attached mbufs.
559 *
560 * In any case the ack and sequence number of the transmitted
561 * segment are as specified by the parameters.
562 */
563 int
564 tcp_respond(struct tcpcb *tp, struct mbuf *template, struct mbuf *m,
565 struct tcphdr *th0, tcp_seq ack, tcp_seq seq, int flags)
566 {
567 struct route *ro;
568 int error, tlen, win = 0;
569 int hlen;
570 struct ip *ip;
571 #ifdef INET6
572 struct ip6_hdr *ip6;
573 #endif
574 int family; /* family on packet, not inpcb/in6pcb! */
575 struct tcphdr *th;
576 struct socket *so;
577
578 if (tp != NULL && (flags & TH_RST) == 0) {
579 #ifdef DIAGNOSTIC
580 if (tp->t_inpcb && tp->t_in6pcb)
581 panic("tcp_respond: both t_inpcb and t_in6pcb are set");
582 #endif
583 #ifdef INET
584 if (tp->t_inpcb)
585 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
586 #endif
587 #ifdef INET6
588 if (tp->t_in6pcb)
589 win = sbspace(&tp->t_in6pcb->in6p_socket->so_rcv);
590 #endif
591 }
592
593 th = NULL; /* Quell uninitialized warning */
594 ip = NULL;
595 #ifdef INET6
596 ip6 = NULL;
597 #endif
598 if (m == 0) {
599 if (!template)
600 return EINVAL;
601
602 /* get family information from template */
603 switch (mtod(template, struct ip *)->ip_v) {
604 case 4:
605 family = AF_INET;
606 hlen = sizeof(struct ip);
607 break;
608 #ifdef INET6
609 case 6:
610 family = AF_INET6;
611 hlen = sizeof(struct ip6_hdr);
612 break;
613 #endif
614 default:
615 return EAFNOSUPPORT;
616 }
617
618 MGETHDR(m, M_DONTWAIT, MT_HEADER);
619 if (m) {
620 MCLAIM(m, &tcp_tx_mowner);
621 MCLGET(m, M_DONTWAIT);
622 if ((m->m_flags & M_EXT) == 0) {
623 m_free(m);
624 m = NULL;
625 }
626 }
627 if (m == NULL)
628 return (ENOBUFS);
629
630 if (tcp_compat_42)
631 tlen = 1;
632 else
633 tlen = 0;
634
635 m->m_data += max_linkhdr;
636 bcopy(mtod(template, caddr_t), mtod(m, caddr_t),
637 template->m_len);
638 switch (family) {
639 case AF_INET:
640 ip = mtod(m, struct ip *);
641 th = (struct tcphdr *)(ip + 1);
642 break;
643 #ifdef INET6
644 case AF_INET6:
645 ip6 = mtod(m, struct ip6_hdr *);
646 th = (struct tcphdr *)(ip6 + 1);
647 break;
648 #endif
649 #if 0
650 default:
651 /* noone will visit here */
652 m_freem(m);
653 return EAFNOSUPPORT;
654 #endif
655 }
656 flags = TH_ACK;
657 } else {
658
659 if ((m->m_flags & M_PKTHDR) == 0) {
660 #if 0
661 printf("non PKTHDR to tcp_respond\n");
662 #endif
663 m_freem(m);
664 return EINVAL;
665 }
666 #ifdef DIAGNOSTIC
667 if (!th0)
668 panic("th0 == NULL in tcp_respond");
669 #endif
670
671 /* get family information from m */
672 switch (mtod(m, struct ip *)->ip_v) {
673 case 4:
674 family = AF_INET;
675 hlen = sizeof(struct ip);
676 ip = mtod(m, struct ip *);
677 break;
678 #ifdef INET6
679 case 6:
680 family = AF_INET6;
681 hlen = sizeof(struct ip6_hdr);
682 ip6 = mtod(m, struct ip6_hdr *);
683 break;
684 #endif
685 default:
686 m_freem(m);
687 return EAFNOSUPPORT;
688 }
689 /* clear h/w csum flags inherited from rx packet */
690 m->m_pkthdr.csum_flags = 0;
691
692 if ((flags & TH_SYN) == 0 || sizeof(*th0) > (th0->th_off << 2))
693 tlen = sizeof(*th0);
694 else
695 tlen = th0->th_off << 2;
696
697 if (m->m_len > hlen + tlen && (m->m_flags & M_EXT) == 0 &&
698 mtod(m, caddr_t) + hlen == (caddr_t)th0) {
699 m->m_len = hlen + tlen;
700 m_freem(m->m_next);
701 m->m_next = NULL;
702 } else {
703 struct mbuf *n;
704
705 #ifdef DIAGNOSTIC
706 if (max_linkhdr + hlen + tlen > MCLBYTES) {
707 m_freem(m);
708 return EMSGSIZE;
709 }
710 #endif
711 MGETHDR(n, M_DONTWAIT, MT_HEADER);
712 if (n && max_linkhdr + hlen + tlen > MHLEN) {
713 MCLGET(n, M_DONTWAIT);
714 if ((n->m_flags & M_EXT) == 0) {
715 m_freem(n);
716 n = NULL;
717 }
718 }
719 if (!n) {
720 m_freem(m);
721 return ENOBUFS;
722 }
723
724 MCLAIM(n, &tcp_tx_mowner);
725 n->m_data += max_linkhdr;
726 n->m_len = hlen + tlen;
727 m_copyback(n, 0, hlen, mtod(m, caddr_t));
728 m_copyback(n, hlen, tlen, (caddr_t)th0);
729
730 m_freem(m);
731 m = n;
732 n = NULL;
733 }
734
735 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
736 switch (family) {
737 case AF_INET:
738 ip = mtod(m, struct ip *);
739 th = (struct tcphdr *)(ip + 1);
740 ip->ip_p = IPPROTO_TCP;
741 xchg(ip->ip_dst, ip->ip_src, struct in_addr);
742 ip->ip_p = IPPROTO_TCP;
743 break;
744 #ifdef INET6
745 case AF_INET6:
746 ip6 = mtod(m, struct ip6_hdr *);
747 th = (struct tcphdr *)(ip6 + 1);
748 ip6->ip6_nxt = IPPROTO_TCP;
749 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
750 ip6->ip6_nxt = IPPROTO_TCP;
751 break;
752 #endif
753 #if 0
754 default:
755 /* noone will visit here */
756 m_freem(m);
757 return EAFNOSUPPORT;
758 #endif
759 }
760 xchg(th->th_dport, th->th_sport, u_int16_t);
761 #undef xchg
762 tlen = 0; /*be friendly with the following code*/
763 }
764 th->th_seq = htonl(seq);
765 th->th_ack = htonl(ack);
766 th->th_x2 = 0;
767 if ((flags & TH_SYN) == 0) {
768 if (tp)
769 win >>= tp->rcv_scale;
770 if (win > TCP_MAXWIN)
771 win = TCP_MAXWIN;
772 th->th_win = htons((u_int16_t)win);
773 th->th_off = sizeof (struct tcphdr) >> 2;
774 tlen += sizeof(*th);
775 } else
776 tlen += th->th_off << 2;
777 m->m_len = hlen + tlen;
778 m->m_pkthdr.len = hlen + tlen;
779 m->m_pkthdr.rcvif = (struct ifnet *) 0;
780 th->th_flags = flags;
781 th->th_urp = 0;
782
783 switch (family) {
784 #ifdef INET
785 case AF_INET:
786 {
787 struct ipovly *ipov = (struct ipovly *)ip;
788 bzero(ipov->ih_x1, sizeof ipov->ih_x1);
789 ipov->ih_len = htons((u_int16_t)tlen);
790
791 th->th_sum = 0;
792 th->th_sum = in_cksum(m, hlen + tlen);
793 ip->ip_len = htons(hlen + tlen);
794 ip->ip_ttl = ip_defttl;
795 break;
796 }
797 #endif
798 #ifdef INET6
799 case AF_INET6:
800 {
801 th->th_sum = 0;
802 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr),
803 tlen);
804 ip6->ip6_plen = htons(tlen);
805 if (tp && tp->t_in6pcb) {
806 struct ifnet *oifp;
807 ro = (struct route *)&tp->t_in6pcb->in6p_route;
808 oifp = ro->ro_rt ? ro->ro_rt->rt_ifp : NULL;
809 ip6->ip6_hlim = in6_selecthlim(tp->t_in6pcb, oifp);
810 } else
811 ip6->ip6_hlim = ip6_defhlim;
812 ip6->ip6_flow &= ~IPV6_FLOWINFO_MASK;
813 if (ip6_auto_flowlabel) {
814 ip6->ip6_flow |=
815 (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK);
816 }
817 break;
818 }
819 #endif
820 }
821
822 if (tp && tp->t_inpcb)
823 so = tp->t_inpcb->inp_socket;
824 #ifdef INET6
825 else if (tp && tp->t_in6pcb)
826 so = tp->t_in6pcb->in6p_socket;
827 #endif
828 else
829 so = NULL;
830
831 if (tp != NULL && tp->t_inpcb != NULL) {
832 ro = &tp->t_inpcb->inp_route;
833 #ifdef DIAGNOSTIC
834 if (family != AF_INET)
835 panic("tcp_respond: address family mismatch");
836 if (!in_hosteq(ip->ip_dst, tp->t_inpcb->inp_faddr)) {
837 panic("tcp_respond: ip_dst %x != inp_faddr %x",
838 ntohl(ip->ip_dst.s_addr),
839 ntohl(tp->t_inpcb->inp_faddr.s_addr));
840 }
841 #endif
842 }
843 #ifdef INET6
844 else if (tp != NULL && tp->t_in6pcb != NULL) {
845 ro = (struct route *)&tp->t_in6pcb->in6p_route;
846 #ifdef DIAGNOSTIC
847 if (family == AF_INET) {
848 if (!IN6_IS_ADDR_V4MAPPED(&tp->t_in6pcb->in6p_faddr))
849 panic("tcp_respond: not mapped addr");
850 if (bcmp(&ip->ip_dst,
851 &tp->t_in6pcb->in6p_faddr.s6_addr32[3],
852 sizeof(ip->ip_dst)) != 0) {
853 panic("tcp_respond: ip_dst != in6p_faddr");
854 }
855 } else if (family == AF_INET6) {
856 if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
857 &tp->t_in6pcb->in6p_faddr))
858 panic("tcp_respond: ip6_dst != in6p_faddr");
859 } else
860 panic("tcp_respond: address family mismatch");
861 #endif
862 }
863 #endif
864 else
865 ro = NULL;
866
867 switch (family) {
868 #ifdef INET
869 case AF_INET:
870 error = ip_output(m, NULL, ro,
871 (tp && tp->t_mtudisc ? IP_MTUDISC : 0),
872 (struct ip_moptions *)0, so);
873 break;
874 #endif
875 #ifdef INET6
876 case AF_INET6:
877 error = ip6_output(m, NULL, (struct route_in6 *)ro, 0,
878 (struct ip6_moptions *)0, so, NULL);
879 break;
880 #endif
881 default:
882 error = EAFNOSUPPORT;
883 break;
884 }
885
886 return (error);
887 }
888
889 /*
890 * Template TCPCB. Rather than zeroing a new TCPCB and initializing
891 * a bunch of members individually, we maintain this template for the
892 * static and mostly-static components of the TCPCB, and copy it into
893 * the new TCPCB instead.
894 */
895 static struct tcpcb tcpcb_template = {
896 /*
897 * If TCP_NTIMERS ever changes, we'll need to update this
898 * initializer.
899 */
900 .t_timer = {
901 CALLOUT_INITIALIZER,
902 CALLOUT_INITIALIZER,
903 CALLOUT_INITIALIZER,
904 CALLOUT_INITIALIZER,
905 },
906 .t_delack_ch = CALLOUT_INITIALIZER,
907
908 .t_srtt = TCPTV_SRTTBASE,
909 .t_rttmin = TCPTV_MIN,
910
911 .snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT,
912 .snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT,
913 .snd_numholes = 0,
914
915 .t_partialacks = -1,
916 };
917
918 /*
919 * Updates the TCPCB template whenever a parameter that would affect
920 * the template is changed.
921 */
922 void
923 tcp_tcpcb_template(void)
924 {
925 struct tcpcb *tp = &tcpcb_template;
926 int flags;
927
928 tp->t_peermss = tcp_mssdflt;
929 tp->t_ourmss = tcp_mssdflt;
930 tp->t_segsz = tcp_mssdflt;
931
932 flags = 0;
933 if (tcp_do_rfc1323 && tcp_do_win_scale)
934 flags |= TF_REQ_SCALE;
935 if (tcp_do_rfc1323 && tcp_do_timestamps)
936 flags |= TF_REQ_TSTMP;
937 tp->t_flags = flags;
938
939 /*
940 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
941 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
942 * reasonable initial retransmit time.
943 */
944 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1);
945 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
946 TCPTV_MIN, TCPTV_REXMTMAX);
947 }
948
949 /*
950 * Create a new TCP control block, making an
951 * empty reassembly queue and hooking it to the argument
952 * protocol control block.
953 */
954 /* family selects inpcb, or in6pcb */
955 struct tcpcb *
956 tcp_newtcpcb(int family, void *aux)
957 {
958 struct tcpcb *tp;
959 int i;
960
961 /* XXX Consider using a pool_cache for speed. */
962 tp = pool_get(&tcpcb_pool, PR_NOWAIT);
963 if (tp == NULL)
964 return (NULL);
965 memcpy(tp, &tcpcb_template, sizeof(*tp));
966 TAILQ_INIT(&tp->segq);
967 TAILQ_INIT(&tp->timeq);
968 tp->t_family = family; /* may be overridden later on */
969 TAILQ_INIT(&tp->snd_holes);
970 LIST_INIT(&tp->t_sc); /* XXX can template this */
971
972 /* Don't sweat this loop; hopefully the compiler will unroll it. */
973 for (i = 0; i < TCPT_NTIMERS; i++)
974 TCP_TIMER_INIT(tp, i);
975
976 switch (family) {
977 case AF_INET:
978 {
979 struct inpcb *inp = (struct inpcb *)aux;
980
981 inp->inp_ip.ip_ttl = ip_defttl;
982 inp->inp_ppcb = (caddr_t)tp;
983
984 tp->t_inpcb = inp;
985 tp->t_mtudisc = ip_mtudisc;
986 break;
987 }
988 #ifdef INET6
989 case AF_INET6:
990 {
991 struct in6pcb *in6p = (struct in6pcb *)aux;
992
993 in6p->in6p_ip6.ip6_hlim = in6_selecthlim(in6p,
994 in6p->in6p_route.ro_rt ? in6p->in6p_route.ro_rt->rt_ifp
995 : NULL);
996 in6p->in6p_ppcb = (caddr_t)tp;
997
998 tp->t_in6pcb = in6p;
999 /* for IPv6, always try to run path MTU discovery */
1000 tp->t_mtudisc = 1;
1001 break;
1002 }
1003 #endif /* INET6 */
1004 default:
1005 pool_put(&tcpcb_pool, tp);
1006 return (NULL);
1007 }
1008
1009 /*
1010 * Initialize our timebase. When we send timestamps, we take
1011 * the delta from tcp_now -- this means each connection always
1012 * gets a timebase of 0, which makes it, among other things,
1013 * more difficult to determine how long a system has been up,
1014 * and thus how many TCP sequence increments have occurred.
1015 */
1016 tp->ts_timebase = tcp_now;
1017
1018 return (tp);
1019 }
1020
1021 /*
1022 * Drop a TCP connection, reporting
1023 * the specified error. If connection is synchronized,
1024 * then send a RST to peer.
1025 */
1026 struct tcpcb *
1027 tcp_drop(struct tcpcb *tp, int errno)
1028 {
1029 struct socket *so = NULL;
1030
1031 #ifdef DIAGNOSTIC
1032 if (tp->t_inpcb && tp->t_in6pcb)
1033 panic("tcp_drop: both t_inpcb and t_in6pcb are set");
1034 #endif
1035 #ifdef INET
1036 if (tp->t_inpcb)
1037 so = tp->t_inpcb->inp_socket;
1038 #endif
1039 #ifdef INET6
1040 if (tp->t_in6pcb)
1041 so = tp->t_in6pcb->in6p_socket;
1042 #endif
1043 if (!so)
1044 return NULL;
1045
1046 if (TCPS_HAVERCVDSYN(tp->t_state)) {
1047 tp->t_state = TCPS_CLOSED;
1048 (void) tcp_output(tp);
1049 tcpstat.tcps_drops++;
1050 } else
1051 tcpstat.tcps_conndrops++;
1052 if (errno == ETIMEDOUT && tp->t_softerror)
1053 errno = tp->t_softerror;
1054 so->so_error = errno;
1055 return (tcp_close(tp));
1056 }
1057
1058 /*
1059 * Return whether this tcpcb is marked as dead, indicating
1060 * to the calling timer function that no further action should
1061 * be taken, as we are about to release this tcpcb. The release
1062 * of the storage will be done if this is the last timer running.
1063 *
1064 * This should be called from the callout handler function after
1065 * callout_ack() is done, so that the number of invoking timer
1066 * functions is 0.
1067 */
1068 int
1069 tcp_isdead(struct tcpcb *tp)
1070 {
1071 int dead = (tp->t_flags & TF_DEAD);
1072
1073 if (__predict_false(dead)) {
1074 if (tcp_timers_invoking(tp) > 0)
1075 /* not quite there yet -- count separately? */
1076 return dead;
1077 tcpstat.tcps_delayed_free++;
1078 pool_put(&tcpcb_pool, tp);
1079 }
1080 return dead;
1081 }
1082
1083 /*
1084 * Close a TCP control block:
1085 * discard all space held by the tcp
1086 * discard internet protocol block
1087 * wake up any sleepers
1088 */
1089 struct tcpcb *
1090 tcp_close(struct tcpcb *tp)
1091 {
1092 struct inpcb *inp;
1093 #ifdef INET6
1094 struct in6pcb *in6p;
1095 #endif
1096 struct socket *so;
1097 #ifdef RTV_RTT
1098 struct rtentry *rt;
1099 #endif
1100 struct route *ro;
1101
1102 inp = tp->t_inpcb;
1103 #ifdef INET6
1104 in6p = tp->t_in6pcb;
1105 #endif
1106 so = NULL;
1107 ro = NULL;
1108 if (inp) {
1109 so = inp->inp_socket;
1110 ro = &inp->inp_route;
1111 }
1112 #ifdef INET6
1113 else if (in6p) {
1114 so = in6p->in6p_socket;
1115 ro = (struct route *)&in6p->in6p_route;
1116 }
1117 #endif
1118
1119 #ifdef RTV_RTT
1120 /*
1121 * If we sent enough data to get some meaningful characteristics,
1122 * save them in the routing entry. 'Enough' is arbitrarily
1123 * defined as the sendpipesize (default 4K) * 16. This would
1124 * give us 16 rtt samples assuming we only get one sample per
1125 * window (the usual case on a long haul net). 16 samples is
1126 * enough for the srtt filter to converge to within 5% of the correct
1127 * value; fewer samples and we could save a very bogus rtt.
1128 *
1129 * Don't update the default route's characteristics and don't
1130 * update anything that the user "locked".
1131 */
1132 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) &&
1133 ro && (rt = ro->ro_rt) &&
1134 !in_nullhost(satosin(rt_key(rt))->sin_addr)) {
1135 u_long i = 0;
1136
1137 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) {
1138 i = tp->t_srtt *
1139 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2));
1140 if (rt->rt_rmx.rmx_rtt && i)
1141 /*
1142 * filter this update to half the old & half
1143 * the new values, converting scale.
1144 * See route.h and tcp_var.h for a
1145 * description of the scaling constants.
1146 */
1147 rt->rt_rmx.rmx_rtt =
1148 (rt->rt_rmx.rmx_rtt + i) / 2;
1149 else
1150 rt->rt_rmx.rmx_rtt = i;
1151 }
1152 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) {
1153 i = tp->t_rttvar *
1154 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2));
1155 if (rt->rt_rmx.rmx_rttvar && i)
1156 rt->rt_rmx.rmx_rttvar =
1157 (rt->rt_rmx.rmx_rttvar + i) / 2;
1158 else
1159 rt->rt_rmx.rmx_rttvar = i;
1160 }
1161 /*
1162 * update the pipelimit (ssthresh) if it has been updated
1163 * already or if a pipesize was specified & the threshhold
1164 * got below half the pipesize. I.e., wait for bad news
1165 * before we start updating, then update on both good
1166 * and bad news.
1167 */
1168 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 &&
1169 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) ||
1170 i < (rt->rt_rmx.rmx_sendpipe / 2)) {
1171 /*
1172 * convert the limit from user data bytes to
1173 * packets then to packet data bytes.
1174 */
1175 i = (i + tp->t_segsz / 2) / tp->t_segsz;
1176 if (i < 2)
1177 i = 2;
1178 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr));
1179 if (rt->rt_rmx.rmx_ssthresh)
1180 rt->rt_rmx.rmx_ssthresh =
1181 (rt->rt_rmx.rmx_ssthresh + i) / 2;
1182 else
1183 rt->rt_rmx.rmx_ssthresh = i;
1184 }
1185 }
1186 #endif /* RTV_RTT */
1187 /* free the reassembly queue, if any */
1188 TCP_REASS_LOCK(tp);
1189 (void) tcp_freeq(tp);
1190 TCP_REASS_UNLOCK(tp);
1191
1192 /* free the SACK holes list. */
1193 tcp_free_sackholes(tp);
1194
1195 tcp_canceltimers(tp);
1196 TCP_CLEAR_DELACK(tp);
1197 syn_cache_cleanup(tp);
1198
1199 if (tp->t_template) {
1200 m_free(tp->t_template);
1201 tp->t_template = NULL;
1202 }
1203 if (tcp_timers_invoking(tp))
1204 tp->t_flags |= TF_DEAD;
1205 else
1206 pool_put(&tcpcb_pool, tp);
1207
1208 if (inp) {
1209 inp->inp_ppcb = 0;
1210 soisdisconnected(so);
1211 in_pcbdetach(inp);
1212 }
1213 #ifdef INET6
1214 else if (in6p) {
1215 in6p->in6p_ppcb = 0;
1216 soisdisconnected(so);
1217 in6_pcbdetach(in6p);
1218 }
1219 #endif
1220 tcpstat.tcps_closed++;
1221 return ((struct tcpcb *)0);
1222 }
1223
1224 int
1225 tcp_freeq(tp)
1226 struct tcpcb *tp;
1227 {
1228 struct ipqent *qe;
1229 int rv = 0;
1230 #ifdef TCPREASS_DEBUG
1231 int i = 0;
1232 #endif
1233
1234 TCP_REASS_LOCK_CHECK(tp);
1235
1236 while ((qe = TAILQ_FIRST(&tp->segq)) != NULL) {
1237 #ifdef TCPREASS_DEBUG
1238 printf("tcp_freeq[%p,%d]: %u:%u(%u) 0x%02x\n",
1239 tp, i++, qe->ipqe_seq, qe->ipqe_seq + qe->ipqe_len,
1240 qe->ipqe_len, qe->ipqe_flags & (TH_SYN|TH_FIN|TH_RST));
1241 #endif
1242 TAILQ_REMOVE(&tp->segq, qe, ipqe_q);
1243 TAILQ_REMOVE(&tp->timeq, qe, ipqe_timeq);
1244 m_freem(qe->ipqe_m);
1245 tcpipqent_free(qe);
1246 rv = 1;
1247 }
1248 tp->t_segqlen = 0;
1249 KASSERT(TAILQ_EMPTY(&tp->timeq));
1250 return (rv);
1251 }
1252
1253 /*
1254 * Protocol drain routine. Called when memory is in short supply.
1255 */
1256 void
1257 tcp_drain(void)
1258 {
1259 struct inpcb_hdr *inph;
1260 struct tcpcb *tp;
1261
1262 /*
1263 * Free the sequence queue of all TCP connections.
1264 */
1265 CIRCLEQ_FOREACH(inph, &tcbtable.inpt_queue, inph_queue) {
1266 switch (inph->inph_af) {
1267 case AF_INET:
1268 tp = intotcpcb((struct inpcb *)inph);
1269 break;
1270 #ifdef INET6
1271 case AF_INET6:
1272 tp = in6totcpcb((struct in6pcb *)inph);
1273 break;
1274 #endif
1275 default:
1276 tp = NULL;
1277 break;
1278 }
1279 if (tp != NULL) {
1280 /*
1281 * We may be called from a device's interrupt
1282 * context. If the tcpcb is already busy,
1283 * just bail out now.
1284 */
1285 if (tcp_reass_lock_try(tp) == 0)
1286 continue;
1287 if (tcp_freeq(tp))
1288 tcpstat.tcps_connsdrained++;
1289 TCP_REASS_UNLOCK(tp);
1290 }
1291 }
1292 }
1293
1294 /*
1295 * Notify a tcp user of an asynchronous error;
1296 * store error as soft error, but wake up user
1297 * (for now, won't do anything until can select for soft error).
1298 */
1299 void
1300 tcp_notify(struct inpcb *inp, int error)
1301 {
1302 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb;
1303 struct socket *so = inp->inp_socket;
1304
1305 /*
1306 * Ignore some errors if we are hooked up.
1307 * If connection hasn't completed, has retransmitted several times,
1308 * and receives a second error, give up now. This is better
1309 * than waiting a long time to establish a connection that
1310 * can never complete.
1311 */
1312 if (tp->t_state == TCPS_ESTABLISHED &&
1313 (error == EHOSTUNREACH || error == ENETUNREACH ||
1314 error == EHOSTDOWN)) {
1315 return;
1316 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 &&
1317 tp->t_rxtshift > 3 && tp->t_softerror)
1318 so->so_error = error;
1319 else
1320 tp->t_softerror = error;
1321 wakeup((caddr_t) &so->so_timeo);
1322 sorwakeup(so);
1323 sowwakeup(so);
1324 }
1325
1326 #ifdef INET6
1327 void
1328 tcp6_notify(struct in6pcb *in6p, int error)
1329 {
1330 struct tcpcb *tp = (struct tcpcb *)in6p->in6p_ppcb;
1331 struct socket *so = in6p->in6p_socket;
1332
1333 /*
1334 * Ignore some errors if we are hooked up.
1335 * If connection hasn't completed, has retransmitted several times,
1336 * and receives a second error, give up now. This is better
1337 * than waiting a long time to establish a connection that
1338 * can never complete.
1339 */
1340 if (tp->t_state == TCPS_ESTABLISHED &&
1341 (error == EHOSTUNREACH || error == ENETUNREACH ||
1342 error == EHOSTDOWN)) {
1343 return;
1344 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 &&
1345 tp->t_rxtshift > 3 && tp->t_softerror)
1346 so->so_error = error;
1347 else
1348 tp->t_softerror = error;
1349 wakeup((caddr_t) &so->so_timeo);
1350 sorwakeup(so);
1351 sowwakeup(so);
1352 }
1353 #endif
1354
1355 #ifdef INET6
1356 void
1357 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
1358 {
1359 struct tcphdr th;
1360 void (*notify)(struct in6pcb *, int) = tcp6_notify;
1361 int nmatch;
1362 struct ip6_hdr *ip6;
1363 const struct sockaddr_in6 *sa6_src = NULL;
1364 struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa;
1365 struct mbuf *m;
1366 int off;
1367
1368 if (sa->sa_family != AF_INET6 ||
1369 sa->sa_len != sizeof(struct sockaddr_in6))
1370 return;
1371 if ((unsigned)cmd >= PRC_NCMDS)
1372 return;
1373 else if (cmd == PRC_QUENCH) {
1374 /* XXX there's no PRC_QUENCH in IPv6 */
1375 notify = tcp6_quench;
1376 } else if (PRC_IS_REDIRECT(cmd))
1377 notify = in6_rtchange, d = NULL;
1378 else if (cmd == PRC_MSGSIZE)
1379 ; /* special code is present, see below */
1380 else if (cmd == PRC_HOSTDEAD)
1381 d = NULL;
1382 else if (inet6ctlerrmap[cmd] == 0)
1383 return;
1384
1385 /* if the parameter is from icmp6, decode it. */
1386 if (d != NULL) {
1387 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
1388 m = ip6cp->ip6c_m;
1389 ip6 = ip6cp->ip6c_ip6;
1390 off = ip6cp->ip6c_off;
1391 sa6_src = ip6cp->ip6c_src;
1392 } else {
1393 m = NULL;
1394 ip6 = NULL;
1395 sa6_src = &sa6_any;
1396 off = 0;
1397 }
1398
1399 if (ip6) {
1400 /*
1401 * XXX: We assume that when ip6 is non NULL,
1402 * M and OFF are valid.
1403 */
1404
1405 /* check if we can safely examine src and dst ports */
1406 if (m->m_pkthdr.len < off + sizeof(th)) {
1407 if (cmd == PRC_MSGSIZE)
1408 icmp6_mtudisc_update((struct ip6ctlparam *)d, 0);
1409 return;
1410 }
1411
1412 bzero(&th, sizeof(th));
1413 m_copydata(m, off, sizeof(th), (caddr_t)&th);
1414
1415 if (cmd == PRC_MSGSIZE) {
1416 int valid = 0;
1417
1418 /*
1419 * Check to see if we have a valid TCP connection
1420 * corresponding to the address in the ICMPv6 message
1421 * payload.
1422 */
1423 if (in6_pcblookup_connect(&tcbtable, &sa6->sin6_addr,
1424 th.th_dport, (struct in6_addr *)&sa6_src->sin6_addr,
1425 th.th_sport, 0))
1426 valid++;
1427
1428 /*
1429 * Depending on the value of "valid" and routing table
1430 * size (mtudisc_{hi,lo}wat), we will:
1431 * - recalcurate the new MTU and create the
1432 * corresponding routing entry, or
1433 * - ignore the MTU change notification.
1434 */
1435 icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
1436
1437 /*
1438 * no need to call in6_pcbnotify, it should have been
1439 * called via callback if necessary
1440 */
1441 return;
1442 }
1443
1444 nmatch = in6_pcbnotify(&tcbtable, sa, th.th_dport,
1445 (struct sockaddr *)sa6_src, th.th_sport, cmd, NULL, notify);
1446 if (nmatch == 0 && syn_cache_count &&
1447 (inet6ctlerrmap[cmd] == EHOSTUNREACH ||
1448 inet6ctlerrmap[cmd] == ENETUNREACH ||
1449 inet6ctlerrmap[cmd] == EHOSTDOWN))
1450 syn_cache_unreach((struct sockaddr *)sa6_src,
1451 sa, &th);
1452 } else {
1453 (void) in6_pcbnotify(&tcbtable, sa, 0,
1454 (struct sockaddr *)sa6_src, 0, cmd, NULL, notify);
1455 }
1456 }
1457 #endif
1458
1459 #ifdef INET
1460 /* assumes that ip header and tcp header are contiguous on mbuf */
1461 void *
1462 tcp_ctlinput(int cmd, struct sockaddr *sa, void *v)
1463 {
1464 struct ip *ip = v;
1465 struct tcphdr *th;
1466 struct icmp *icp;
1467 extern const int inetctlerrmap[];
1468 void (*notify)(struct inpcb *, int) = tcp_notify;
1469 int errno;
1470 int nmatch;
1471 #ifdef INET6
1472 struct in6_addr src6, dst6;
1473 #endif
1474
1475 if (sa->sa_family != AF_INET ||
1476 sa->sa_len != sizeof(struct sockaddr_in))
1477 return NULL;
1478 if ((unsigned)cmd >= PRC_NCMDS)
1479 return NULL;
1480 errno = inetctlerrmap[cmd];
1481 if (cmd == PRC_QUENCH)
1482 notify = tcp_quench;
1483 else if (PRC_IS_REDIRECT(cmd))
1484 notify = in_rtchange, ip = 0;
1485 else if (cmd == PRC_MSGSIZE && ip && ip->ip_v == 4) {
1486 /*
1487 * Check to see if we have a valid TCP connection
1488 * corresponding to the address in the ICMP message
1489 * payload.
1490 *
1491 * Boundary check is made in icmp_input(), with ICMP_ADVLENMIN.
1492 */
1493 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
1494 #ifdef INET6
1495 memset(&src6, 0, sizeof(src6));
1496 memset(&dst6, 0, sizeof(dst6));
1497 src6.s6_addr16[5] = dst6.s6_addr16[5] = 0xffff;
1498 memcpy(&src6.s6_addr32[3], &ip->ip_src, sizeof(struct in_addr));
1499 memcpy(&dst6.s6_addr32[3], &ip->ip_dst, sizeof(struct in_addr));
1500 #endif
1501 if (in_pcblookup_connect(&tcbtable, ip->ip_dst, th->th_dport,
1502 ip->ip_src, th->th_sport) != NULL)
1503 ;
1504 #ifdef INET6
1505 else if (in6_pcblookup_connect(&tcbtable, &dst6,
1506 th->th_dport, &src6, th->th_sport, 0) != NULL)
1507 ;
1508 #endif
1509 else
1510 return NULL;
1511
1512 /*
1513 * Now that we've validated that we are actually communicating
1514 * with the host indicated in the ICMP message, locate the
1515 * ICMP header, recalculate the new MTU, and create the
1516 * corresponding routing entry.
1517 */
1518 icp = (struct icmp *)((caddr_t)ip -
1519 offsetof(struct icmp, icmp_ip));
1520 icmp_mtudisc(icp, ip->ip_dst);
1521
1522 return NULL;
1523 } else if (cmd == PRC_HOSTDEAD)
1524 ip = 0;
1525 else if (errno == 0)
1526 return NULL;
1527 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) {
1528 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
1529 nmatch = in_pcbnotify(&tcbtable, satosin(sa)->sin_addr,
1530 th->th_dport, ip->ip_src, th->th_sport, errno, notify);
1531 if (nmatch == 0 && syn_cache_count &&
1532 (inetctlerrmap[cmd] == EHOSTUNREACH ||
1533 inetctlerrmap[cmd] == ENETUNREACH ||
1534 inetctlerrmap[cmd] == EHOSTDOWN)) {
1535 struct sockaddr_in sin;
1536 bzero(&sin, sizeof(sin));
1537 sin.sin_len = sizeof(sin);
1538 sin.sin_family = AF_INET;
1539 sin.sin_port = th->th_sport;
1540 sin.sin_addr = ip->ip_src;
1541 syn_cache_unreach((struct sockaddr *)&sin, sa, th);
1542 }
1543
1544 /* XXX mapped address case */
1545 } else
1546 in_pcbnotifyall(&tcbtable, satosin(sa)->sin_addr, errno,
1547 notify);
1548 return NULL;
1549 }
1550
1551 /*
1552 * When a source quench is received, we are being notified of congestion.
1553 * Close the congestion window down to the Loss Window (one segment).
1554 * We will gradually open it again as we proceed.
1555 */
1556 void
1557 tcp_quench(struct inpcb *inp, int errno)
1558 {
1559 struct tcpcb *tp = intotcpcb(inp);
1560
1561 if (tp)
1562 tp->snd_cwnd = tp->t_segsz;
1563 }
1564 #endif
1565
1566 #ifdef INET6
1567 void
1568 tcp6_quench(struct in6pcb *in6p, int errno)
1569 {
1570 struct tcpcb *tp = in6totcpcb(in6p);
1571
1572 if (tp)
1573 tp->snd_cwnd = tp->t_segsz;
1574 }
1575 #endif
1576
1577 #ifdef INET
1578 /*
1579 * Path MTU Discovery handlers.
1580 */
1581 void
1582 tcp_mtudisc_callback(struct in_addr faddr)
1583 {
1584 #ifdef INET6
1585 struct in6_addr in6;
1586 #endif
1587
1588 in_pcbnotifyall(&tcbtable, faddr, EMSGSIZE, tcp_mtudisc);
1589 #ifdef INET6
1590 memset(&in6, 0, sizeof(in6));
1591 in6.s6_addr16[5] = 0xffff;
1592 memcpy(&in6.s6_addr32[3], &faddr, sizeof(struct in_addr));
1593 tcp6_mtudisc_callback(&in6);
1594 #endif
1595 }
1596
1597 /*
1598 * On receipt of path MTU corrections, flush old route and replace it
1599 * with the new one. Retransmit all unacknowledged packets, to ensure
1600 * that all packets will be received.
1601 */
1602 void
1603 tcp_mtudisc(struct inpcb *inp, int errno)
1604 {
1605 struct tcpcb *tp = intotcpcb(inp);
1606 struct rtentry *rt = in_pcbrtentry(inp);
1607
1608 if (tp != 0) {
1609 if (rt != 0) {
1610 /*
1611 * If this was not a host route, remove and realloc.
1612 */
1613 if ((rt->rt_flags & RTF_HOST) == 0) {
1614 in_rtchange(inp, errno);
1615 if ((rt = in_pcbrtentry(inp)) == 0)
1616 return;
1617 }
1618
1619 /*
1620 * Slow start out of the error condition. We
1621 * use the MTU because we know it's smaller
1622 * than the previously transmitted segment.
1623 *
1624 * Note: This is more conservative than the
1625 * suggestion in draft-floyd-incr-init-win-03.
1626 */
1627 if (rt->rt_rmx.rmx_mtu != 0)
1628 tp->snd_cwnd =
1629 TCP_INITIAL_WINDOW(tcp_init_win,
1630 rt->rt_rmx.rmx_mtu);
1631 }
1632
1633 /*
1634 * Resend unacknowledged packets.
1635 */
1636 tp->snd_nxt = tp->snd_una;
1637 tcp_output(tp);
1638 }
1639 }
1640 #endif
1641
1642 #ifdef INET6
1643 /*
1644 * Path MTU Discovery handlers.
1645 */
1646 void
1647 tcp6_mtudisc_callback(struct in6_addr *faddr)
1648 {
1649 struct sockaddr_in6 sin6;
1650
1651 bzero(&sin6, sizeof(sin6));
1652 sin6.sin6_family = AF_INET6;
1653 sin6.sin6_len = sizeof(struct sockaddr_in6);
1654 sin6.sin6_addr = *faddr;
1655 (void) in6_pcbnotify(&tcbtable, (struct sockaddr *)&sin6, 0,
1656 (struct sockaddr *)&sa6_any, 0, PRC_MSGSIZE, NULL, tcp6_mtudisc);
1657 }
1658
1659 void
1660 tcp6_mtudisc(struct in6pcb *in6p, int errno)
1661 {
1662 struct tcpcb *tp = in6totcpcb(in6p);
1663 struct rtentry *rt = in6_pcbrtentry(in6p);
1664
1665 if (tp != 0) {
1666 if (rt != 0) {
1667 /*
1668 * If this was not a host route, remove and realloc.
1669 */
1670 if ((rt->rt_flags & RTF_HOST) == 0) {
1671 in6_rtchange(in6p, errno);
1672 if ((rt = in6_pcbrtentry(in6p)) == 0)
1673 return;
1674 }
1675
1676 /*
1677 * Slow start out of the error condition. We
1678 * use the MTU because we know it's smaller
1679 * than the previously transmitted segment.
1680 *
1681 * Note: This is more conservative than the
1682 * suggestion in draft-floyd-incr-init-win-03.
1683 */
1684 if (rt->rt_rmx.rmx_mtu != 0)
1685 tp->snd_cwnd =
1686 TCP_INITIAL_WINDOW(tcp_init_win,
1687 rt->rt_rmx.rmx_mtu);
1688 }
1689
1690 /*
1691 * Resend unacknowledged packets.
1692 */
1693 tp->snd_nxt = tp->snd_una;
1694 tcp_output(tp);
1695 }
1696 }
1697 #endif /* INET6 */
1698
1699 /*
1700 * Compute the MSS to advertise to the peer. Called only during
1701 * the 3-way handshake. If we are the server (peer initiated
1702 * connection), we are called with a pointer to the interface
1703 * on which the SYN packet arrived. If we are the client (we
1704 * initiated connection), we are called with a pointer to the
1705 * interface out which this connection should go.
1706 *
1707 * NOTE: Do not subtract IP option/extension header size nor IPsec
1708 * header size from MSS advertisement. MSS option must hold the maximum
1709 * segment size we can accept, so it must always be:
1710 * max(if mtu) - ip header - tcp header
1711 */
1712 u_long
1713 tcp_mss_to_advertise(const struct ifnet *ifp, int af)
1714 {
1715 extern u_long in_maxmtu;
1716 u_long mss = 0;
1717 u_long hdrsiz;
1718
1719 /*
1720 * In order to avoid defeating path MTU discovery on the peer,
1721 * we advertise the max MTU of all attached networks as our MSS,
1722 * per RFC 1191, section 3.1.
1723 *
1724 * We provide the option to advertise just the MTU of
1725 * the interface on which we hope this connection will
1726 * be receiving. If we are responding to a SYN, we
1727 * will have a pretty good idea about this, but when
1728 * initiating a connection there is a bit more doubt.
1729 *
1730 * We also need to ensure that loopback has a large enough
1731 * MSS, as the loopback MTU is never included in in_maxmtu.
1732 */
1733
1734 if (ifp != NULL)
1735 switch (af) {
1736 case AF_INET:
1737 mss = ifp->if_mtu;
1738 break;
1739 #ifdef INET6
1740 case AF_INET6:
1741 mss = IN6_LINKMTU(ifp);
1742 break;
1743 #endif
1744 }
1745
1746 if (tcp_mss_ifmtu == 0)
1747 switch (af) {
1748 case AF_INET:
1749 mss = max(in_maxmtu, mss);
1750 break;
1751 #ifdef INET6
1752 case AF_INET6:
1753 mss = max(in6_maxmtu, mss);
1754 break;
1755 #endif
1756 }
1757
1758 switch (af) {
1759 case AF_INET:
1760 hdrsiz = sizeof(struct ip);
1761 break;
1762 #ifdef INET6
1763 case AF_INET6:
1764 hdrsiz = sizeof(struct ip6_hdr);
1765 break;
1766 #endif
1767 default:
1768 hdrsiz = 0;
1769 break;
1770 }
1771 hdrsiz += sizeof(struct tcphdr);
1772 if (mss > hdrsiz)
1773 mss -= hdrsiz;
1774
1775 mss = max(tcp_mssdflt, mss);
1776 return (mss);
1777 }
1778
1779 /*
1780 * Set connection variables based on the peer's advertised MSS.
1781 * We are passed the TCPCB for the actual connection. If we
1782 * are the server, we are called by the compressed state engine
1783 * when the 3-way handshake is complete. If we are the client,
1784 * we are called when we receive the SYN,ACK from the server.
1785 *
1786 * NOTE: Our advertised MSS value must be initialized in the TCPCB
1787 * before this routine is called!
1788 */
1789 void
1790 tcp_mss_from_peer(struct tcpcb *tp, int offer)
1791 {
1792 struct socket *so;
1793 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
1794 struct rtentry *rt;
1795 #endif
1796 u_long bufsize;
1797 int mss;
1798
1799 #ifdef DIAGNOSTIC
1800 if (tp->t_inpcb && tp->t_in6pcb)
1801 panic("tcp_mss_from_peer: both t_inpcb and t_in6pcb are set");
1802 #endif
1803 so = NULL;
1804 rt = NULL;
1805 #ifdef INET
1806 if (tp->t_inpcb) {
1807 so = tp->t_inpcb->inp_socket;
1808 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
1809 rt = in_pcbrtentry(tp->t_inpcb);
1810 #endif
1811 }
1812 #endif
1813 #ifdef INET6
1814 if (tp->t_in6pcb) {
1815 so = tp->t_in6pcb->in6p_socket;
1816 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
1817 rt = in6_pcbrtentry(tp->t_in6pcb);
1818 #endif
1819 }
1820 #endif
1821
1822 /*
1823 * As per RFC1122, use the default MSS value, unless they
1824 * sent us an offer. Do not accept offers less than 256 bytes.
1825 */
1826 mss = tcp_mssdflt;
1827 if (offer)
1828 mss = offer;
1829 mss = max(mss, 256); /* sanity */
1830 tp->t_peermss = mss;
1831 mss -= tcp_optlen(tp);
1832 #ifdef INET
1833 if (tp->t_inpcb)
1834 mss -= ip_optlen(tp->t_inpcb);
1835 #endif
1836 #ifdef INET6
1837 if (tp->t_in6pcb)
1838 mss -= ip6_optlen(tp->t_in6pcb);
1839 #endif
1840
1841 /*
1842 * If there's a pipesize, change the socket buffer to that size.
1843 * Make the socket buffer an integral number of MSS units. If
1844 * the MSS is larger than the socket buffer, artificially decrease
1845 * the MSS.
1846 */
1847 #ifdef RTV_SPIPE
1848 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0)
1849 bufsize = rt->rt_rmx.rmx_sendpipe;
1850 else
1851 #endif
1852 bufsize = so->so_snd.sb_hiwat;
1853 if (bufsize < mss)
1854 mss = bufsize;
1855 else {
1856 bufsize = roundup(bufsize, mss);
1857 if (bufsize > sb_max)
1858 bufsize = sb_max;
1859 (void) sbreserve(&so->so_snd, bufsize, so);
1860 }
1861 tp->t_segsz = mss;
1862
1863 #ifdef RTV_SSTHRESH
1864 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) {
1865 /*
1866 * There's some sort of gateway or interface buffer
1867 * limit on the path. Use this to set the slow
1868 * start threshold, but set the threshold to no less
1869 * than 2 * MSS.
1870 */
1871 tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh);
1872 }
1873 #endif
1874 }
1875
1876 /*
1877 * Processing necessary when a TCP connection is established.
1878 */
1879 void
1880 tcp_established(struct tcpcb *tp)
1881 {
1882 struct socket *so;
1883 #ifdef RTV_RPIPE
1884 struct rtentry *rt;
1885 #endif
1886 u_long bufsize;
1887
1888 #ifdef DIAGNOSTIC
1889 if (tp->t_inpcb && tp->t_in6pcb)
1890 panic("tcp_established: both t_inpcb and t_in6pcb are set");
1891 #endif
1892 so = NULL;
1893 rt = NULL;
1894 #ifdef INET
1895 if (tp->t_inpcb) {
1896 so = tp->t_inpcb->inp_socket;
1897 #if defined(RTV_RPIPE)
1898 rt = in_pcbrtentry(tp->t_inpcb);
1899 #endif
1900 }
1901 #endif
1902 #ifdef INET6
1903 if (tp->t_in6pcb) {
1904 so = tp->t_in6pcb->in6p_socket;
1905 #if defined(RTV_RPIPE)
1906 rt = in6_pcbrtentry(tp->t_in6pcb);
1907 #endif
1908 }
1909 #endif
1910
1911 tp->t_state = TCPS_ESTABLISHED;
1912 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle);
1913
1914 #ifdef RTV_RPIPE
1915 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0)
1916 bufsize = rt->rt_rmx.rmx_recvpipe;
1917 else
1918 #endif
1919 bufsize = so->so_rcv.sb_hiwat;
1920 if (bufsize > tp->t_ourmss) {
1921 bufsize = roundup(bufsize, tp->t_ourmss);
1922 if (bufsize > sb_max)
1923 bufsize = sb_max;
1924 (void) sbreserve(&so->so_rcv, bufsize, so);
1925 }
1926 }
1927
1928 /*
1929 * Check if there's an initial rtt or rttvar. Convert from the
1930 * route-table units to scaled multiples of the slow timeout timer.
1931 * Called only during the 3-way handshake.
1932 */
1933 void
1934 tcp_rmx_rtt(struct tcpcb *tp)
1935 {
1936 #ifdef RTV_RTT
1937 struct rtentry *rt = NULL;
1938 int rtt;
1939
1940 #ifdef DIAGNOSTIC
1941 if (tp->t_inpcb && tp->t_in6pcb)
1942 panic("tcp_rmx_rtt: both t_inpcb and t_in6pcb are set");
1943 #endif
1944 #ifdef INET
1945 if (tp->t_inpcb)
1946 rt = in_pcbrtentry(tp->t_inpcb);
1947 #endif
1948 #ifdef INET6
1949 if (tp->t_in6pcb)
1950 rt = in6_pcbrtentry(tp->t_in6pcb);
1951 #endif
1952 if (rt == NULL)
1953 return;
1954
1955 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) {
1956 /*
1957 * XXX The lock bit for MTU indicates that the value
1958 * is also a minimum value; this is subject to time.
1959 */
1960 if (rt->rt_rmx.rmx_locks & RTV_RTT)
1961 TCPT_RANGESET(tp->t_rttmin,
1962 rtt / (RTM_RTTUNIT / PR_SLOWHZ),
1963 TCPTV_MIN, TCPTV_REXMTMAX);
1964 tp->t_srtt = rtt /
1965 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2));
1966 if (rt->rt_rmx.rmx_rttvar) {
1967 tp->t_rttvar = rt->rt_rmx.rmx_rttvar /
1968 ((RTM_RTTUNIT / PR_SLOWHZ) >>
1969 (TCP_RTTVAR_SHIFT + 2));
1970 } else {
1971 /* Default variation is +- 1 rtt */
1972 tp->t_rttvar =
1973 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT);
1974 }
1975 TCPT_RANGESET(tp->t_rxtcur,
1976 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2),
1977 tp->t_rttmin, TCPTV_REXMTMAX);
1978 }
1979 #endif
1980 }
1981
1982 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */
1983 #if NRND > 0
1984 u_int8_t tcp_iss_secret[16]; /* 128 bits; should be plenty */
1985 #endif
1986
1987 /*
1988 * Get a new sequence value given a tcp control block
1989 */
1990 tcp_seq
1991 tcp_new_iss(struct tcpcb *tp, tcp_seq addin)
1992 {
1993
1994 #ifdef INET
1995 if (tp->t_inpcb != NULL) {
1996 return (tcp_new_iss1(&tp->t_inpcb->inp_laddr,
1997 &tp->t_inpcb->inp_faddr, tp->t_inpcb->inp_lport,
1998 tp->t_inpcb->inp_fport, sizeof(tp->t_inpcb->inp_laddr),
1999 addin));
2000 }
2001 #endif
2002 #ifdef INET6
2003 if (tp->t_in6pcb != NULL) {
2004 return (tcp_new_iss1(&tp->t_in6pcb->in6p_laddr,
2005 &tp->t_in6pcb->in6p_faddr, tp->t_in6pcb->in6p_lport,
2006 tp->t_in6pcb->in6p_fport, sizeof(tp->t_in6pcb->in6p_laddr),
2007 addin));
2008 }
2009 #endif
2010 /* Not possible. */
2011 panic("tcp_new_iss");
2012 }
2013
2014 /*
2015 * This routine actually generates a new TCP initial sequence number.
2016 */
2017 tcp_seq
2018 tcp_new_iss1(void *laddr, void *faddr, u_int16_t lport, u_int16_t fport,
2019 size_t addrsz, tcp_seq addin)
2020 {
2021 tcp_seq tcp_iss;
2022
2023 #if NRND > 0
2024 static int beenhere;
2025
2026 /*
2027 * If we haven't been here before, initialize our cryptographic
2028 * hash secret.
2029 */
2030 if (beenhere == 0) {
2031 rnd_extract_data(tcp_iss_secret, sizeof(tcp_iss_secret),
2032 RND_EXTRACT_ANY);
2033 beenhere = 1;
2034 }
2035
2036 if (tcp_do_rfc1948) {
2037 MD5_CTX ctx;
2038 u_int8_t hash[16]; /* XXX MD5 knowledge */
2039
2040 /*
2041 * Compute the base value of the ISS. It is a hash
2042 * of (saddr, sport, daddr, dport, secret).
2043 */
2044 MD5Init(&ctx);
2045
2046 MD5Update(&ctx, (u_char *) laddr, addrsz);
2047 MD5Update(&ctx, (u_char *) &lport, sizeof(lport));
2048
2049 MD5Update(&ctx, (u_char *) faddr, addrsz);
2050 MD5Update(&ctx, (u_char *) &fport, sizeof(fport));
2051
2052 MD5Update(&ctx, tcp_iss_secret, sizeof(tcp_iss_secret));
2053
2054 MD5Final(hash, &ctx);
2055
2056 memcpy(&tcp_iss, hash, sizeof(tcp_iss));
2057
2058 /*
2059 * Now increment our "timer", and add it in to
2060 * the computed value.
2061 *
2062 * XXX Use `addin'?
2063 * XXX TCP_ISSINCR too large to use?
2064 */
2065 tcp_iss_seq += TCP_ISSINCR;
2066 #ifdef TCPISS_DEBUG
2067 printf("ISS hash 0x%08x, ", tcp_iss);
2068 #endif
2069 tcp_iss += tcp_iss_seq + addin;
2070 #ifdef TCPISS_DEBUG
2071 printf("new ISS 0x%08x\n", tcp_iss);
2072 #endif
2073 } else
2074 #endif /* NRND > 0 */
2075 {
2076 /*
2077 * Randomize.
2078 */
2079 #if NRND > 0
2080 rnd_extract_data(&tcp_iss, sizeof(tcp_iss), RND_EXTRACT_ANY);
2081 #else
2082 tcp_iss = arc4random();
2083 #endif
2084
2085 /*
2086 * If we were asked to add some amount to a known value,
2087 * we will take a random value obtained above, mask off
2088 * the upper bits, and add in the known value. We also
2089 * add in a constant to ensure that we are at least a
2090 * certain distance from the original value.
2091 *
2092 * This is used when an old connection is in timed wait
2093 * and we have a new one coming in, for instance.
2094 */
2095 if (addin != 0) {
2096 #ifdef TCPISS_DEBUG
2097 printf("Random %08x, ", tcp_iss);
2098 #endif
2099 tcp_iss &= TCP_ISS_RANDOM_MASK;
2100 tcp_iss += addin + TCP_ISSINCR;
2101 #ifdef TCPISS_DEBUG
2102 printf("Old ISS %08x, ISS %08x\n", addin, tcp_iss);
2103 #endif
2104 } else {
2105 tcp_iss &= TCP_ISS_RANDOM_MASK;
2106 tcp_iss += tcp_iss_seq;
2107 tcp_iss_seq += TCP_ISSINCR;
2108 #ifdef TCPISS_DEBUG
2109 printf("ISS %08x\n", tcp_iss);
2110 #endif
2111 }
2112 }
2113
2114 if (tcp_compat_42) {
2115 /*
2116 * Limit it to the positive range for really old TCP
2117 * implementations.
2118 * Just AND off the top bit instead of checking if
2119 * is set first - saves a branch 50% of the time.
2120 */
2121 tcp_iss &= 0x7fffffff; /* XXX */
2122 }
2123
2124 return (tcp_iss);
2125 }
2126
2127 #if defined(IPSEC) || defined(FAST_IPSEC)
2128 /* compute ESP/AH header size for TCP, including outer IP header. */
2129 size_t
2130 ipsec4_hdrsiz_tcp(struct tcpcb *tp)
2131 {
2132 struct inpcb *inp;
2133 size_t hdrsiz;
2134
2135 /* XXX mapped addr case (tp->t_in6pcb) */
2136 if (!tp || !tp->t_template || !(inp = tp->t_inpcb))
2137 return 0;
2138 switch (tp->t_family) {
2139 case AF_INET:
2140 /* XXX: should use currect direction. */
2141 hdrsiz = ipsec4_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp);
2142 break;
2143 default:
2144 hdrsiz = 0;
2145 break;
2146 }
2147
2148 return hdrsiz;
2149 }
2150
2151 #ifdef INET6
2152 size_t
2153 ipsec6_hdrsiz_tcp(struct tcpcb *tp)
2154 {
2155 struct in6pcb *in6p;
2156 size_t hdrsiz;
2157
2158 if (!tp || !tp->t_template || !(in6p = tp->t_in6pcb))
2159 return 0;
2160 switch (tp->t_family) {
2161 case AF_INET6:
2162 /* XXX: should use currect direction. */
2163 hdrsiz = ipsec6_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, in6p);
2164 break;
2165 case AF_INET:
2166 /* mapped address case - tricky */
2167 default:
2168 hdrsiz = 0;
2169 break;
2170 }
2171
2172 return hdrsiz;
2173 }
2174 #endif
2175 #endif /*IPSEC*/
2176
2177 /*
2178 * Determine the length of the TCP options for this connection.
2179 *
2180 * XXX: What do we do for SACK, when we add that? Just reserve
2181 * all of the space? Otherwise we can't exactly be incrementing
2182 * cwnd by an amount that varies depending on the amount we last
2183 * had to SACK!
2184 */
2185
2186 u_int
2187 tcp_optlen(struct tcpcb *tp)
2188 {
2189 u_int optlen;
2190
2191 optlen = 0;
2192 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) ==
2193 (TF_REQ_TSTMP | TF_RCVD_TSTMP))
2194 optlen += TCPOLEN_TSTAMP_APPA;
2195
2196 #ifdef TCP_SIGNATURE
2197 #if defined(INET6) && defined(FAST_IPSEC)
2198 if (tp->t_family == AF_INET)
2199 #endif
2200 if (tp->t_flags & TF_SIGNATURE)
2201 optlen += TCPOLEN_SIGNATURE + 2;
2202 #endif /* TCP_SIGNATURE */
2203
2204 return optlen;
2205 }
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