1 /* $NetBSD: tcp_subr.c,v 1.298 2025/02/26 04:49:45 andvar 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, 2008 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 *
49 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
50 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
51 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
52 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
53 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
54 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
55 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
56 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
57 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
58 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
59 * POSSIBILITY OF SUCH DAMAGE.
60 */
61
62 /*
63 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
64 * The Regents of the University of California. All rights reserved.
65 *
66 * Redistribution and use in source and binary forms, with or without
67 * modification, are permitted provided that the following conditions
68 * are met:
69 * 1. Redistributions of source code must retain the above copyright
70 * notice, this list of conditions and the following disclaimer.
71 * 2. Redistributions in binary form must reproduce the above copyright
72 * notice, this list of conditions and the following disclaimer in the
73 * documentation and/or other materials provided with the distribution.
74 * 3. Neither the name of the University nor the names of its contributors
75 * may be used to endorse or promote products derived from this software
76 * without specific prior written permission.
77 *
78 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
79 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
80 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
81 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
82 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
83 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
84 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
85 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
86 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
87 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
88 * SUCH DAMAGE.
89 *
90 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
91 */
92
93 #include <sys/cdefs.h>
94 __KERNEL_RCSID(0, "$NetBSD: tcp_subr.c,v 1.298 2025/02/26 04:49:45 andvar Exp $");
95
96 #ifdef _KERNEL_OPT
97 #include "opt_inet.h"
98 #include "opt_ipsec.h"
99 #include "opt_inet_csum.h"
100 #include "opt_mbuftrace.h"
101 #endif
102
103 #include <sys/param.h>
104 #include <sys/atomic.h>
105 #include <sys/proc.h>
106 #include <sys/systm.h>
107 #include <sys/mbuf.h>
108 #include <sys/once.h>
109 #include <sys/socket.h>
110 #include <sys/socketvar.h>
111 #include <sys/protosw.h>
112 #include <sys/errno.h>
113 #include <sys/kernel.h>
114 #include <sys/pool.h>
115 #include <sys/md5.h>
116 #include <sys/cprng.h>
117
118 #include <net/route.h>
119 #include <net/if.h>
120
121 #include <netinet/in.h>
122 #include <netinet/in_systm.h>
123 #include <netinet/ip.h>
124 #include <netinet/in_pcb.h>
125 #include <netinet/ip_var.h>
126 #include <netinet/ip_icmp.h>
127
128 #ifdef INET6
129 #include <netinet/ip6.h>
130 #include <netinet6/in6_pcb.h>
131 #include <netinet6/ip6_var.h>
132 #include <netinet6/in6_var.h>
133 #include <netinet6/ip6protosw.h>
134 #include <netinet/icmp6.h>
135 #include <netinet6/nd6.h>
136 #endif
137
138 #include <netinet/tcp.h>
139 #include <netinet/tcp_fsm.h>
140 #include <netinet/tcp_seq.h>
141 #include <netinet/tcp_timer.h>
142 #include <netinet/tcp_var.h>
143 #include <netinet/tcp_vtw.h>
144 #include <netinet/tcp_private.h>
145 #include <netinet/tcp_congctl.h>
146 #include <netinet/tcp_syncache.h>
147
148 #ifdef IPSEC
149 #include <netipsec/ipsec.h>
150 #ifdef INET6
151 #include <netipsec/ipsec6.h>
152 #endif
153 #include <netipsec/key.h>
154 #endif
155
156
157 struct inpcbtable tcbtable; /* head of queue of active tcpcb's */
158 u_int32_t tcp_now; /* slow ticks, for RFC 1323 timestamps */
159
160 percpu_t *tcpstat_percpu;
161
162 /* patchable/settable parameters for tcp */
163 int tcp_mssdflt = TCP_MSS;
164 int tcp_minmss = TCP_MINMSS;
165 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
166 int tcp_do_rfc1323 = 1; /* window scaling / timestamps (obsolete) */
167 int tcp_do_rfc1948 = 0; /* ISS by cryptographic hash */
168 int tcp_do_sack = 1; /* selective acknowledgement */
169 int tcp_do_win_scale = 1; /* RFC1323 window scaling */
170 int tcp_do_timestamps = 1; /* RFC1323 timestamps */
171 int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */
172 int tcp_do_ecn = 0; /* Explicit Congestion Notification */
173 #ifndef TCP_INIT_WIN
174 #define TCP_INIT_WIN 4 /* initial slow start window */
175 #endif
176 #ifndef TCP_INIT_WIN_LOCAL
177 #define TCP_INIT_WIN_LOCAL 4 /* initial slow start window for local nets */
178 #endif
179 /*
180 * Up to 5 we scale linearly, to reach 3 * 1460; then (iw) * 1460.
181 * This is to simulate current behavior for iw == 4
182 */
183 int tcp_init_win_max[] = {
184 1 * 1460,
185 1 * 1460,
186 2 * 1460,
187 2 * 1460,
188 3 * 1460,
189 5 * 1460,
190 6 * 1460,
191 7 * 1460,
192 8 * 1460,
193 9 * 1460,
194 10 * 1460
195 };
196 int tcp_init_win = TCP_INIT_WIN;
197 int tcp_init_win_local = TCP_INIT_WIN_LOCAL;
198 int tcp_mss_ifmtu = 0;
199 int tcp_rst_ppslim = 100; /* 100pps */
200 int tcp_ackdrop_ppslim = 100; /* 100pps */
201 int tcp_do_loopback_cksum = 0;
202 int tcp_do_abc = 1; /* RFC3465 Appropriate byte counting. */
203 int tcp_abc_aggressive = 1; /* 1: L=2*SMSS 0: L=1*SMSS */
204 int tcp_sack_tp_maxholes = 32;
205 int tcp_sack_globalmaxholes = 1024;
206 int tcp_sack_globalholes = 0;
207 int tcp_ecn_maxretries = 1;
208 int tcp_msl_enable = 1; /* enable TIME_WAIT truncation */
209 int tcp_msl_loop = PR_SLOWHZ; /* MSL for loopback */
210 int tcp_msl_local = 5 * PR_SLOWHZ; /* MSL for 'local' */
211 int tcp_msl_remote = TCPTV_MSL; /* MSL otherwise */
212 int tcp_msl_remote_threshold = TCPTV_SRTTDFLT; /* RTT threshold */
213 int tcp_rttlocal = 0; /* Use RTT to decide who's 'local' */
214
215 int tcp4_vtw_enable = 0; /* 1 to enable */
216 int tcp6_vtw_enable = 0; /* 1 to enable */
217 int tcp_vtw_was_enabled = 0;
218 int tcp_vtw_entries = 1 << 4; /* 16 vestigial TIME_WAIT entries */
219
220 /* tcb hash */
221 #ifndef TCBHASHSIZE
222 #define TCBHASHSIZE 128
223 #endif
224 int tcbhashsize = TCBHASHSIZE;
225
226 int tcp_freeq(struct tcpcb *);
227 static int tcp_iss_secret_init(void);
228
229 static void tcp_mtudisc_callback(struct in_addr);
230
231 #ifdef INET6
232 static void tcp6_mtudisc(struct inpcb *, int);
233 #endif
234
235 static struct pool tcpcb_pool;
236
237 static int tcp_drainwanted;
238
239 #ifdef TCP_CSUM_COUNTERS
240 #include <sys/device.h>
241
242 struct evcnt tcp_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
243 NULL, "tcp", "hwcsum bad");
244 struct evcnt tcp_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
245 NULL, "tcp", "hwcsum ok");
246 struct evcnt tcp_hwcsum_data = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
247 NULL, "tcp", "hwcsum data");
248 struct evcnt tcp_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
249 NULL, "tcp", "swcsum");
250
251 EVCNT_ATTACH_STATIC(tcp_hwcsum_bad);
252 EVCNT_ATTACH_STATIC(tcp_hwcsum_ok);
253 EVCNT_ATTACH_STATIC(tcp_hwcsum_data);
254 EVCNT_ATTACH_STATIC(tcp_swcsum);
255
256 #if defined(INET6)
257 struct evcnt tcp6_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
258 NULL, "tcp6", "hwcsum bad");
259 struct evcnt tcp6_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
260 NULL, "tcp6", "hwcsum ok");
261 struct evcnt tcp6_hwcsum_data = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
262 NULL, "tcp6", "hwcsum data");
263 struct evcnt tcp6_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
264 NULL, "tcp6", "swcsum");
265
266 EVCNT_ATTACH_STATIC(tcp6_hwcsum_bad);
267 EVCNT_ATTACH_STATIC(tcp6_hwcsum_ok);
268 EVCNT_ATTACH_STATIC(tcp6_hwcsum_data);
269 EVCNT_ATTACH_STATIC(tcp6_swcsum);
270 #endif /* defined(INET6) */
271 #endif /* TCP_CSUM_COUNTERS */
272
273
274 #ifdef TCP_OUTPUT_COUNTERS
275 #include <sys/device.h>
276
277 struct evcnt tcp_output_bigheader = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
278 NULL, "tcp", "output big header");
279 struct evcnt tcp_output_predict_hit = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
280 NULL, "tcp", "output predict hit");
281 struct evcnt tcp_output_predict_miss = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
282 NULL, "tcp", "output predict miss");
283 struct evcnt tcp_output_copysmall = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
284 NULL, "tcp", "output copy small");
285 struct evcnt tcp_output_copybig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
286 NULL, "tcp", "output copy big");
287 struct evcnt tcp_output_refbig = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
288 NULL, "tcp", "output reference big");
289
290 EVCNT_ATTACH_STATIC(tcp_output_bigheader);
291 EVCNT_ATTACH_STATIC(tcp_output_predict_hit);
292 EVCNT_ATTACH_STATIC(tcp_output_predict_miss);
293 EVCNT_ATTACH_STATIC(tcp_output_copysmall);
294 EVCNT_ATTACH_STATIC(tcp_output_copybig);
295 EVCNT_ATTACH_STATIC(tcp_output_refbig);
296
297 #endif /* TCP_OUTPUT_COUNTERS */
298
299 #ifdef TCP_REASS_COUNTERS
300 #include <sys/device.h>
301
302 struct evcnt tcp_reass_ = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
303 NULL, "tcp_reass", "calls");
304 struct evcnt tcp_reass_empty = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
305 &tcp_reass_, "tcp_reass", "insert into empty queue");
306 struct evcnt tcp_reass_iteration[8] = {
307 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", ">7 iterations"),
308 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "1 iteration"),
309 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "2 iterations"),
310 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "3 iterations"),
311 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "4 iterations"),
312 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "5 iterations"),
313 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "6 iterations"),
314 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, &tcp_reass_, "tcp_reass", "7 iterations"),
315 };
316 struct evcnt tcp_reass_prependfirst = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
317 &tcp_reass_, "tcp_reass", "prepend to first");
318 struct evcnt tcp_reass_prepend = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
319 &tcp_reass_, "tcp_reass", "prepend");
320 struct evcnt tcp_reass_insert = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
321 &tcp_reass_, "tcp_reass", "insert");
322 struct evcnt tcp_reass_inserttail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
323 &tcp_reass_, "tcp_reass", "insert at tail");
324 struct evcnt tcp_reass_append = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
325 &tcp_reass_, "tcp_reass", "append");
326 struct evcnt tcp_reass_appendtail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
327 &tcp_reass_, "tcp_reass", "append to tail fragment");
328 struct evcnt tcp_reass_overlaptail = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
329 &tcp_reass_, "tcp_reass", "overlap at end");
330 struct evcnt tcp_reass_overlapfront = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
331 &tcp_reass_, "tcp_reass", "overlap at start");
332 struct evcnt tcp_reass_segdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
333 &tcp_reass_, "tcp_reass", "duplicate segment");
334 struct evcnt tcp_reass_fragdup = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
335 &tcp_reass_, "tcp_reass", "duplicate fragment");
336
337 EVCNT_ATTACH_STATIC(tcp_reass_);
338 EVCNT_ATTACH_STATIC(tcp_reass_empty);
339 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 0);
340 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 1);
341 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 2);
342 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 3);
343 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 4);
344 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 5);
345 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 6);
346 EVCNT_ATTACH_STATIC2(tcp_reass_iteration, 7);
347 EVCNT_ATTACH_STATIC(tcp_reass_prependfirst);
348 EVCNT_ATTACH_STATIC(tcp_reass_prepend);
349 EVCNT_ATTACH_STATIC(tcp_reass_insert);
350 EVCNT_ATTACH_STATIC(tcp_reass_inserttail);
351 EVCNT_ATTACH_STATIC(tcp_reass_append);
352 EVCNT_ATTACH_STATIC(tcp_reass_appendtail);
353 EVCNT_ATTACH_STATIC(tcp_reass_overlaptail);
354 EVCNT_ATTACH_STATIC(tcp_reass_overlapfront);
355 EVCNT_ATTACH_STATIC(tcp_reass_segdup);
356 EVCNT_ATTACH_STATIC(tcp_reass_fragdup);
357
358 #endif /* TCP_REASS_COUNTERS */
359
360 #ifdef MBUFTRACE
361 struct mowner tcp_mowner = MOWNER_INIT("tcp", "");
362 struct mowner tcp_rx_mowner = MOWNER_INIT("tcp", "rx");
363 struct mowner tcp_tx_mowner = MOWNER_INIT("tcp", "tx");
364 struct mowner tcp_sock_mowner = MOWNER_INIT("tcp", "sock");
365 struct mowner tcp_sock_rx_mowner = MOWNER_INIT("tcp", "sock rx");
366 struct mowner tcp_sock_tx_mowner = MOWNER_INIT("tcp", "sock tx");
367 #endif
368
369 static int
do_tcpinit(void)370 do_tcpinit(void)
371 {
372
373 inpcb_init(&tcbtable, tcbhashsize, tcbhashsize);
374 pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl",
375 NULL, IPL_SOFTNET);
376
377 tcp_usrreq_init();
378
379 /* Initialize timer state. */
380 tcp_timer_init();
381
382 /* Initialize the compressed state engine. */
383 syn_cache_init();
384
385 /* Initialize the congestion control algorithms. */
386 tcp_congctl_init();
387
388 /* Initialize the TCPCB template. */
389 tcp_tcpcb_template();
390
391 /* Initialize reassembly queue */
392 tcpipqent_init();
393
394 /* SACK */
395 tcp_sack_init();
396
397 MOWNER_ATTACH(&tcp_tx_mowner);
398 MOWNER_ATTACH(&tcp_rx_mowner);
399 MOWNER_ATTACH(&tcp_reass_mowner);
400 MOWNER_ATTACH(&tcp_sock_mowner);
401 MOWNER_ATTACH(&tcp_sock_tx_mowner);
402 MOWNER_ATTACH(&tcp_sock_rx_mowner);
403 MOWNER_ATTACH(&tcp_mowner);
404
405 tcpstat_percpu = percpu_alloc(sizeof(uint64_t) * TCP_NSTATS);
406
407 vtw_earlyinit();
408
409 tcp_slowtimo_init();
410
411 return 0;
412 }
413
414 void
tcp_init_common(unsigned basehlen)415 tcp_init_common(unsigned basehlen)
416 {
417 static ONCE_DECL(dotcpinit);
418 unsigned hlen = basehlen + sizeof(struct tcphdr);
419 unsigned oldhlen;
420
421 if (max_linkhdr + hlen > MHLEN)
422 panic("tcp_init");
423 while ((oldhlen = max_protohdr) < hlen)
424 atomic_cas_uint(&max_protohdr, oldhlen, hlen);
425
426 RUN_ONCE(&dotcpinit, do_tcpinit);
427 }
428
429 /*
430 * Tcp initialization
431 */
432 void
tcp_init(void)433 tcp_init(void)
434 {
435
436 icmp_mtudisc_callback_register(tcp_mtudisc_callback);
437
438 tcp_init_common(sizeof(struct ip));
439 }
440
441 /*
442 * Create template to be used to send tcp packets on a connection.
443 * Call after host entry created, allocates an mbuf and fills
444 * in a skeletal tcp/ip header, minimizing the amount of work
445 * necessary when the connection is used.
446 */
447 struct mbuf *
tcp_template(struct tcpcb * tp)448 tcp_template(struct tcpcb *tp)
449 {
450 struct inpcb *inp = tp->t_inpcb;
451 struct tcphdr *n;
452 struct mbuf *m;
453 int hlen;
454
455 switch (tp->t_family) {
456 case AF_INET:
457 hlen = sizeof(struct ip);
458 if (inp->inp_af == AF_INET)
459 break;
460 #ifdef INET6
461 if (inp->inp_af == AF_INET6) {
462 /* mapped addr case */
463 if (IN6_IS_ADDR_V4MAPPED(&in6p_laddr(inp))
464 && IN6_IS_ADDR_V4MAPPED(&in6p_faddr(inp)))
465 break;
466 }
467 #endif
468 return NULL; /*EINVAL*/
469 #ifdef INET6
470 case AF_INET6:
471 hlen = sizeof(struct ip6_hdr);
472 if (inp != NULL) {
473 /* more sainty check? */
474 break;
475 }
476 return NULL; /*EINVAL*/
477 #endif
478 default:
479 return NULL; /*EAFNOSUPPORT*/
480 }
481
482 KASSERT(hlen + sizeof(struct tcphdr) <= MCLBYTES);
483
484 m = tp->t_template;
485 if (m && m->m_len == hlen + sizeof(struct tcphdr)) {
486 ;
487 } else {
488 m_freem(m);
489 m = tp->t_template = NULL;
490 MGETHDR(m, M_DONTWAIT, MT_HEADER);
491 if (m && hlen + sizeof(struct tcphdr) > MHLEN) {
492 MCLGET(m, M_DONTWAIT);
493 if ((m->m_flags & M_EXT) == 0) {
494 m_free(m);
495 m = NULL;
496 }
497 }
498 if (m == NULL)
499 return NULL;
500 MCLAIM(m, &tcp_mowner);
501 m->m_pkthdr.len = m->m_len = hlen + sizeof(struct tcphdr);
502 }
503
504 memset(mtod(m, void *), 0, m->m_len);
505
506 n = (struct tcphdr *)(mtod(m, char *) + hlen);
507
508 switch (tp->t_family) {
509 case AF_INET:
510 {
511 struct ipovly *ipov;
512 mtod(m, struct ip *)->ip_v = 4;
513 mtod(m, struct ip *)->ip_hl = hlen >> 2;
514 ipov = mtod(m, struct ipovly *);
515 ipov->ih_pr = IPPROTO_TCP;
516 ipov->ih_len = htons(sizeof(struct tcphdr));
517 if (inp->inp_af == AF_INET) {
518 ipov->ih_src = in4p_laddr(inp);
519 ipov->ih_dst = in4p_faddr(inp);
520 }
521 #ifdef INET6
522 else if (inp->inp_af == AF_INET6) {
523 /* mapped addr case */
524 bcopy(&in6p_laddr(inp).s6_addr32[3], &ipov->ih_src,
525 sizeof(ipov->ih_src));
526 bcopy(&in6p_faddr(inp).s6_addr32[3], &ipov->ih_dst,
527 sizeof(ipov->ih_dst));
528 }
529 #endif
530
531 /*
532 * Compute the pseudo-header portion of the checksum
533 * now. We incrementally add in the TCP option and
534 * payload lengths later, and then compute the TCP
535 * checksum right before the packet is sent off onto
536 * the wire.
537 */
538 n->th_sum = in_cksum_phdr(ipov->ih_src.s_addr,
539 ipov->ih_dst.s_addr,
540 htons(sizeof(struct tcphdr) + IPPROTO_TCP));
541 break;
542 }
543 #ifdef INET6
544 case AF_INET6:
545 {
546 struct ip6_hdr *ip6;
547 mtod(m, struct ip *)->ip_v = 6;
548 ip6 = mtod(m, struct ip6_hdr *);
549 ip6->ip6_nxt = IPPROTO_TCP;
550 ip6->ip6_plen = htons(sizeof(struct tcphdr));
551 ip6->ip6_src = in6p_laddr(inp);
552 ip6->ip6_dst = in6p_faddr(inp);
553 ip6->ip6_flow = in6p_flowinfo(inp) & IPV6_FLOWINFO_MASK;
554 if (ip6_auto_flowlabel) {
555 ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK;
556 ip6->ip6_flow |=
557 (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK);
558 }
559 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
560 ip6->ip6_vfc |= IPV6_VERSION;
561
562 /*
563 * Compute the pseudo-header portion of the checksum
564 * now. We incrementally add in the TCP option and
565 * payload lengths later, and then compute the TCP
566 * checksum right before the packet is sent off onto
567 * the wire.
568 */
569 n->th_sum = in6_cksum_phdr(&in6p_laddr(inp),
570 &in6p_faddr(inp), htonl(sizeof(struct tcphdr)),
571 htonl(IPPROTO_TCP));
572 break;
573 }
574 #endif
575 }
576
577 n->th_sport = inp->inp_lport;
578 n->th_dport = inp->inp_fport;
579
580 n->th_seq = 0;
581 n->th_ack = 0;
582 n->th_x2 = 0;
583 n->th_off = 5;
584 n->th_flags = 0;
585 n->th_win = 0;
586 n->th_urp = 0;
587 return m;
588 }
589
590 /*
591 * Send a single message to the TCP at address specified by
592 * the given TCP/IP header. If m == 0, then we make a copy
593 * of the tcpiphdr at ti and send directly to the addressed host.
594 * This is used to force keep alive messages out using the TCP
595 * template for a connection tp->t_template. If flags are given
596 * then we send a message back to the TCP which originated the
597 * segment ti, and discard the mbuf containing it and any other
598 * attached mbufs.
599 *
600 * In any case the ack and sequence number of the transmitted
601 * segment are as specified by the parameters.
602 */
603 int
tcp_respond(struct tcpcb * tp,struct mbuf * mtemplate,struct mbuf * m,struct tcphdr * th0,tcp_seq ack,tcp_seq seq,int flags)604 tcp_respond(struct tcpcb *tp, struct mbuf *mtemplate, struct mbuf *m,
605 struct tcphdr *th0, tcp_seq ack, tcp_seq seq, int flags)
606 {
607 struct route *ro;
608 int error, tlen, win = 0;
609 int hlen;
610 struct ip *ip;
611 #ifdef INET6
612 struct ip6_hdr *ip6;
613 #endif
614 int family; /* family on packet, not inpcb! */
615 struct tcphdr *th;
616
617 if (tp != NULL && (flags & TH_RST) == 0) {
618 KASSERT(tp->t_inpcb != NULL);
619
620 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
621 }
622
623 th = NULL; /* Quell uninitialized warning */
624 ip = NULL;
625 #ifdef INET6
626 ip6 = NULL;
627 #endif
628 if (m == NULL) {
629 if (!mtemplate)
630 return EINVAL;
631
632 /* get family information from template */
633 switch (mtod(mtemplate, struct ip *)->ip_v) {
634 case 4:
635 family = AF_INET;
636 hlen = sizeof(struct ip);
637 break;
638 #ifdef INET6
639 case 6:
640 family = AF_INET6;
641 hlen = sizeof(struct ip6_hdr);
642 break;
643 #endif
644 default:
645 return EAFNOSUPPORT;
646 }
647
648 MGETHDR(m, M_DONTWAIT, MT_HEADER);
649 if (m) {
650 MCLAIM(m, &tcp_tx_mowner);
651 MCLGET(m, M_DONTWAIT);
652 if ((m->m_flags & M_EXT) == 0) {
653 m_free(m);
654 m = NULL;
655 }
656 }
657 if (m == NULL)
658 return ENOBUFS;
659
660 tlen = 0;
661
662 m->m_data += max_linkhdr;
663 bcopy(mtod(mtemplate, void *), mtod(m, void *),
664 mtemplate->m_len);
665 switch (family) {
666 case AF_INET:
667 ip = mtod(m, struct ip *);
668 th = (struct tcphdr *)(ip + 1);
669 break;
670 #ifdef INET6
671 case AF_INET6:
672 ip6 = mtod(m, struct ip6_hdr *);
673 th = (struct tcphdr *)(ip6 + 1);
674 break;
675 #endif
676 }
677 flags = TH_ACK;
678 } else {
679 if ((m->m_flags & M_PKTHDR) == 0) {
680 m_freem(m);
681 return EINVAL;
682 }
683 KASSERT(th0 != NULL);
684
685 /* get family information from m */
686 switch (mtod(m, struct ip *)->ip_v) {
687 case 4:
688 family = AF_INET;
689 hlen = sizeof(struct ip);
690 ip = mtod(m, struct ip *);
691 break;
692 #ifdef INET6
693 case 6:
694 family = AF_INET6;
695 hlen = sizeof(struct ip6_hdr);
696 ip6 = mtod(m, struct ip6_hdr *);
697 break;
698 #endif
699 default:
700 m_freem(m);
701 return EAFNOSUPPORT;
702 }
703 /* clear h/w csum flags inherited from rx packet */
704 m->m_pkthdr.csum_flags = 0;
705
706 if ((flags & TH_SYN) == 0 || sizeof(*th0) > (th0->th_off << 2))
707 tlen = sizeof(*th0);
708 else
709 tlen = th0->th_off << 2;
710
711 if (m->m_len > hlen + tlen && (m->m_flags & M_EXT) == 0 &&
712 mtod(m, char *) + hlen == (char *)th0) {
713 m->m_len = hlen + tlen;
714 m_freem(m->m_next);
715 m->m_next = NULL;
716 } else {
717 struct mbuf *n;
718
719 KASSERT(max_linkhdr + hlen + tlen <= MCLBYTES);
720
721 MGETHDR(n, M_DONTWAIT, MT_HEADER);
722 if (n && max_linkhdr + hlen + tlen > MHLEN) {
723 MCLGET(n, M_DONTWAIT);
724 if ((n->m_flags & M_EXT) == 0) {
725 m_freem(n);
726 n = NULL;
727 }
728 }
729 if (!n) {
730 m_freem(m);
731 return ENOBUFS;
732 }
733
734 MCLAIM(n, &tcp_tx_mowner);
735 n->m_data += max_linkhdr;
736 n->m_len = hlen + tlen;
737 m_copyback(n, 0, hlen, mtod(m, void *));
738 m_copyback(n, hlen, tlen, (void *)th0);
739
740 m_freem(m);
741 m = n;
742 n = NULL;
743 }
744
745 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
746 switch (family) {
747 case AF_INET:
748 ip = mtod(m, struct ip *);
749 th = (struct tcphdr *)(ip + 1);
750 ip->ip_p = IPPROTO_TCP;
751 xchg(ip->ip_dst, ip->ip_src, struct in_addr);
752 ip->ip_p = IPPROTO_TCP;
753 break;
754 #ifdef INET6
755 case AF_INET6:
756 ip6 = mtod(m, struct ip6_hdr *);
757 th = (struct tcphdr *)(ip6 + 1);
758 ip6->ip6_nxt = IPPROTO_TCP;
759 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
760 ip6->ip6_nxt = IPPROTO_TCP;
761 break;
762 #endif
763 }
764 xchg(th->th_dport, th->th_sport, u_int16_t);
765 #undef xchg
766 tlen = 0; /*be friendly with the following code*/
767 }
768 th->th_seq = htonl(seq);
769 th->th_ack = htonl(ack);
770 th->th_x2 = 0;
771 if ((flags & TH_SYN) == 0) {
772 if (tp)
773 win >>= tp->rcv_scale;
774 if (win > TCP_MAXWIN)
775 win = TCP_MAXWIN;
776 th->th_win = htons((u_int16_t)win);
777 th->th_off = sizeof (struct tcphdr) >> 2;
778 tlen += sizeof(*th);
779 } else {
780 tlen += th->th_off << 2;
781 }
782 m->m_len = hlen + tlen;
783 m->m_pkthdr.len = hlen + tlen;
784 m_reset_rcvif(m);
785 th->th_flags = flags;
786 th->th_urp = 0;
787
788 switch (family) {
789 case AF_INET:
790 {
791 struct ipovly *ipov = (struct ipovly *)ip;
792 memset(ipov->ih_x1, 0, sizeof ipov->ih_x1);
793 ipov->ih_len = htons((u_int16_t)tlen);
794
795 th->th_sum = 0;
796 th->th_sum = in_cksum(m, hlen + tlen);
797 ip->ip_len = htons(hlen + tlen);
798 ip->ip_ttl = ip_defttl;
799 break;
800 }
801 #ifdef INET6
802 case AF_INET6:
803 {
804 th->th_sum = 0;
805 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr),
806 tlen);
807 ip6->ip6_plen = htons(tlen);
808 if (tp && tp->t_inpcb->inp_af == AF_INET6)
809 ip6->ip6_hlim = in6pcb_selecthlim_rt(tp->t_inpcb);
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 != NULL && tp->t_inpcb->inp_af == AF_INET) {
823 ro = &tp->t_inpcb->inp_route;
824 KASSERT(family == AF_INET);
825 KASSERT(in_hosteq(ip->ip_dst, in4p_faddr(tp->t_inpcb)));
826 }
827 #ifdef INET6
828 else if (tp != NULL && tp->t_inpcb->inp_af == AF_INET6) {
829 ro = (struct route *)&tp->t_inpcb->inp_route;
830
831 #ifdef DIAGNOSTIC
832 if (family == AF_INET) {
833 if (!IN6_IS_ADDR_V4MAPPED(&in6p_faddr(tp->t_inpcb)))
834 panic("tcp_respond: not mapped addr");
835 if (memcmp(&ip->ip_dst,
836 &in6p_faddr(tp->t_inpcb).s6_addr32[3],
837 sizeof(ip->ip_dst)) != 0) {
838 panic("tcp_respond: ip_dst != in6p_faddr");
839 }
840 } else if (family == AF_INET6) {
841 if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
842 &in6p_faddr(tp->t_inpcb)))
843 panic("tcp_respond: ip6_dst != in6p_faddr");
844 } else
845 panic("tcp_respond: address family mismatch");
846 #endif
847 }
848 #endif
849 else
850 ro = NULL;
851
852 switch (family) {
853 case AF_INET:
854 error = ip_output(m, NULL, ro,
855 (tp && tp->t_mtudisc ? IP_MTUDISC : 0), NULL,
856 tp ? tp->t_inpcb : NULL);
857 break;
858 #ifdef INET6
859 case AF_INET6:
860 error = ip6_output(m, NULL, ro, 0, NULL,
861 tp ? tp->t_inpcb : NULL, NULL);
862 break;
863 #endif
864 default:
865 error = EAFNOSUPPORT;
866 break;
867 }
868
869 return error;
870 }
871
872 /*
873 * Template TCPCB. Rather than zeroing a new TCPCB and initializing
874 * a bunch of members individually, we maintain this template for the
875 * static and mostly-static components of the TCPCB, and copy it into
876 * the new TCPCB instead.
877 */
878 static struct tcpcb tcpcb_template = {
879 .t_srtt = TCPTV_SRTTBASE,
880 .t_rttmin = TCPTV_MIN,
881
882 .snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT,
883 .snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT,
884 .snd_numholes = 0,
885 .snd_cubic_wmax = 0,
886 .snd_cubic_wmax_last = 0,
887 .snd_cubic_ctime = 0,
888
889 .t_partialacks = -1,
890 .t_bytes_acked = 0,
891 .t_sndrexmitpack = 0,
892 .t_rcvoopack = 0,
893 .t_sndzerowin = 0,
894 };
895
896 /*
897 * Updates the TCPCB template whenever a parameter that would affect
898 * the template is changed.
899 */
900 void
tcp_tcpcb_template(void)901 tcp_tcpcb_template(void)
902 {
903 struct tcpcb *tp = &tcpcb_template;
904 int flags;
905
906 tp->t_peermss = tcp_mssdflt;
907 tp->t_ourmss = tcp_mssdflt;
908 tp->t_segsz = tcp_mssdflt;
909
910 flags = 0;
911 if (tcp_do_rfc1323 && tcp_do_win_scale)
912 flags |= TF_REQ_SCALE;
913 if (tcp_do_rfc1323 && tcp_do_timestamps)
914 flags |= TF_REQ_TSTMP;
915 tp->t_flags = flags;
916
917 /*
918 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
919 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
920 * reasonable initial retransmit time.
921 */
922 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1);
923 TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
924 TCPTV_MIN, TCPTV_REXMTMAX);
925
926 /* Keep Alive */
927 tp->t_keepinit = MIN(tcp_keepinit, TCP_TIMER_MAXTICKS);
928 tp->t_keepidle = MIN(tcp_keepidle, TCP_TIMER_MAXTICKS);
929 tp->t_keepintvl = MIN(tcp_keepintvl, TCP_TIMER_MAXTICKS);
930 tp->t_keepcnt = MAX(1, MIN(tcp_keepcnt, TCP_TIMER_MAXTICKS));
931 tp->t_maxidle = tp->t_keepcnt * MIN(tp->t_keepintvl,
932 TCP_TIMER_MAXTICKS/tp->t_keepcnt);
933
934 /* MSL */
935 tp->t_msl = TCPTV_MSL;
936 }
937
938 /*
939 * Create a new TCP control block, making an
940 * empty reassembly queue and hooking it to the argument
941 * protocol control block.
942 */
943 struct tcpcb *
tcp_newtcpcb(int family,struct inpcb * inp)944 tcp_newtcpcb(int family, struct inpcb *inp)
945 {
946 struct tcpcb *tp;
947 int i;
948
949 /* XXX Consider using a pool_cache for speed. */
950 tp = pool_get(&tcpcb_pool, PR_NOWAIT); /* splsoftnet via tcp_usrreq */
951 if (tp == NULL)
952 return NULL;
953 memcpy(tp, &tcpcb_template, sizeof(*tp));
954 TAILQ_INIT(&tp->segq);
955 TAILQ_INIT(&tp->timeq);
956 tp->t_family = family; /* may be overridden later on */
957 TAILQ_INIT(&tp->snd_holes);
958 LIST_INIT(&tp->t_sc); /* XXX can template this */
959
960 /* Don't sweat this loop; hopefully the compiler will unroll it. */
961 for (i = 0; i < TCPT_NTIMERS; i++) {
962 callout_init(&tp->t_timer[i], CALLOUT_MPSAFE);
963 TCP_TIMER_INIT(tp, i);
964 }
965 callout_init(&tp->t_delack_ch, CALLOUT_MPSAFE);
966
967 switch (family) {
968 case AF_INET:
969 in4p_ip(inp).ip_ttl = ip_defttl;
970 inp->inp_ppcb = (void *)tp;
971
972 tp->t_inpcb = inp;
973 tp->t_mtudisc = ip_mtudisc;
974 break;
975 #ifdef INET6
976 case AF_INET6:
977 in6p_ip6(inp).ip6_hlim = in6pcb_selecthlim_rt(inp);
978 inp->inp_ppcb = (void *)tp;
979
980 tp->t_inpcb = inp;
981 /* for IPv6, always try to run path MTU discovery */
982 tp->t_mtudisc = 1;
983 break;
984 #endif /* INET6 */
985 default:
986 for (i = 0; i < TCPT_NTIMERS; i++)
987 callout_destroy(&tp->t_timer[i]);
988 callout_destroy(&tp->t_delack_ch);
989 pool_put(&tcpcb_pool, tp); /* splsoftnet via tcp_usrreq */
990 return NULL;
991 }
992
993 /*
994 * Initialize our timebase. When we send timestamps, we take
995 * the delta from tcp_now -- this means each connection always
996 * gets a timebase of 1, which makes it, among other things,
997 * more difficult to determine how long a system has been up,
998 * and thus how many TCP sequence increments have occurred.
999 *
1000 * We start with 1, because 0 doesn't work with linux, which
1001 * considers timestamp 0 in a SYN packet as a bug and disables
1002 * timestamps.
1003 */
1004 tp->ts_timebase = tcp_now - 1;
1005
1006 tcp_congctl_select(tp, tcp_congctl_global_name);
1007
1008 return tp;
1009 }
1010
1011 /*
1012 * Drop a TCP connection, reporting
1013 * the specified error. If connection is synchronized,
1014 * then send a RST to peer.
1015 */
1016 struct tcpcb *
tcp_drop(struct tcpcb * tp,int errno)1017 tcp_drop(struct tcpcb *tp, int errno)
1018 {
1019 struct socket *so;
1020
1021 KASSERT(tp->t_inpcb != NULL);
1022
1023 so = tp->t_inpcb->inp_socket;
1024 if (so == NULL)
1025 return NULL;
1026
1027 if (TCPS_HAVERCVDSYN(tp->t_state)) {
1028 tp->t_state = TCPS_CLOSED;
1029 (void) tcp_output(tp);
1030 TCP_STATINC(TCP_STAT_DROPS);
1031 } else
1032 TCP_STATINC(TCP_STAT_CONNDROPS);
1033 if (errno == ETIMEDOUT && tp->t_softerror)
1034 errno = tp->t_softerror;
1035 so->so_error = errno;
1036 return (tcp_close(tp));
1037 }
1038
1039 /*
1040 * Close a TCP control block:
1041 * discard all space held by the tcp
1042 * discard internet protocol block
1043 * wake up any sleepers
1044 */
1045 struct tcpcb *
tcp_close(struct tcpcb * tp)1046 tcp_close(struct tcpcb *tp)
1047 {
1048 struct inpcb *inp;
1049 struct socket *so;
1050 #ifdef RTV_RTT
1051 struct rtentry *rt = NULL;
1052 #endif
1053 struct route *ro;
1054 int j;
1055
1056 inp = tp->t_inpcb;
1057 so = inp->inp_socket;
1058 ro = &inp->inp_route;
1059
1060 #ifdef RTV_RTT
1061 /*
1062 * If we sent enough data to get some meaningful characteristics,
1063 * save them in the routing entry. 'Enough' is arbitrarily
1064 * defined as the sendpipesize (default 4K) * 16. This would
1065 * give us 16 rtt samples assuming we only get one sample per
1066 * window (the usual case on a long haul net). 16 samples is
1067 * enough for the srtt filter to converge to within 5% of the correct
1068 * value; fewer samples and we could save a very bogus rtt.
1069 *
1070 * Don't update the default route's characteristics and don't
1071 * update anything that the user "locked".
1072 */
1073 if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) &&
1074 ro && (rt = rtcache_validate(ro)) != NULL &&
1075 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr)) {
1076 u_long i = 0;
1077
1078 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) {
1079 i = tp->t_srtt *
1080 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2));
1081 if (rt->rt_rmx.rmx_rtt && i)
1082 /*
1083 * filter this update to half the old & half
1084 * the new values, converting scale.
1085 * See route.h and tcp_var.h for a
1086 * description of the scaling constants.
1087 */
1088 rt->rt_rmx.rmx_rtt =
1089 (rt->rt_rmx.rmx_rtt + i) / 2;
1090 else
1091 rt->rt_rmx.rmx_rtt = i;
1092 }
1093 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) {
1094 i = tp->t_rttvar *
1095 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2));
1096 if (rt->rt_rmx.rmx_rttvar && i)
1097 rt->rt_rmx.rmx_rttvar =
1098 (rt->rt_rmx.rmx_rttvar + i) / 2;
1099 else
1100 rt->rt_rmx.rmx_rttvar = i;
1101 }
1102 /*
1103 * update the pipelimit (ssthresh) if it has been updated
1104 * already or if a pipesize was specified & the threshold
1105 * got below half the pipesize. I.e., wait for bad news
1106 * before we start updating, then update on both good
1107 * and bad news.
1108 */
1109 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 &&
1110 (i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) ||
1111 i < (rt->rt_rmx.rmx_sendpipe / 2)) {
1112 /*
1113 * convert the limit from user data bytes to
1114 * packets then to packet data bytes.
1115 */
1116 i = (i + tp->t_segsz / 2) / tp->t_segsz;
1117 if (i < 2)
1118 i = 2;
1119 i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr));
1120 if (rt->rt_rmx.rmx_ssthresh)
1121 rt->rt_rmx.rmx_ssthresh =
1122 (rt->rt_rmx.rmx_ssthresh + i) / 2;
1123 else
1124 rt->rt_rmx.rmx_ssthresh = i;
1125 }
1126 }
1127 rtcache_unref(rt, ro);
1128 #endif /* RTV_RTT */
1129 /* free the reassembly queue, if any */
1130 TCP_REASS_LOCK(tp);
1131 (void) tcp_freeq(tp);
1132 TCP_REASS_UNLOCK(tp);
1133
1134 /* free the SACK holes list. */
1135 tcp_free_sackholes(tp);
1136 tcp_congctl_release(tp);
1137 syn_cache_cleanup(tp);
1138
1139 if (tp->t_template) {
1140 m_free(tp->t_template);
1141 tp->t_template = NULL;
1142 }
1143
1144 /*
1145 * Detaching the pcb will unlock the socket/tcpcb, and stopping
1146 * the timers can also drop the lock. We need to prevent access
1147 * to the tcpcb as it's half torn down. Flag the pcb as dead
1148 * (prevents access by timers) and only then detach it.
1149 */
1150 tp->t_flags |= TF_DEAD;
1151 inp->inp_ppcb = NULL;
1152 soisdisconnected(so);
1153 inpcb_destroy(inp);
1154 /*
1155 * pcb is no longer visble elsewhere, so we can safely release
1156 * the lock in callout_halt() if needed.
1157 */
1158 TCP_STATINC(TCP_STAT_CLOSED);
1159 for (j = 0; j < TCPT_NTIMERS; j++) {
1160 callout_halt(&tp->t_timer[j], softnet_lock);
1161 callout_destroy(&tp->t_timer[j]);
1162 }
1163 callout_halt(&tp->t_delack_ch, softnet_lock);
1164 callout_destroy(&tp->t_delack_ch);
1165 pool_put(&tcpcb_pool, tp);
1166
1167 return NULL;
1168 }
1169
1170 int
tcp_freeq(struct tcpcb * tp)1171 tcp_freeq(struct tcpcb *tp)
1172 {
1173 struct ipqent *qe;
1174 int rv = 0;
1175
1176 TCP_REASS_LOCK_CHECK(tp);
1177
1178 while ((qe = TAILQ_FIRST(&tp->segq)) != NULL) {
1179 TAILQ_REMOVE(&tp->segq, qe, ipqe_q);
1180 TAILQ_REMOVE(&tp->timeq, qe, ipqe_timeq);
1181 m_freem(qe->ipqe_m);
1182 tcpipqent_free(qe);
1183 rv = 1;
1184 }
1185 tp->t_segqlen = 0;
1186 KASSERT(TAILQ_EMPTY(&tp->timeq));
1187 return (rv);
1188 }
1189
1190 void
tcp_fasttimo(void)1191 tcp_fasttimo(void)
1192 {
1193 if (tcp_drainwanted) {
1194 tcp_drain();
1195 tcp_drainwanted = 0;
1196 }
1197 }
1198
1199 void
tcp_drainstub(void)1200 tcp_drainstub(void)
1201 {
1202 tcp_drainwanted = 1;
1203 }
1204
1205 /*
1206 * Protocol drain routine. Called when memory is in short supply.
1207 * Called from pr_fasttimo thus a callout context.
1208 */
1209 void
tcp_drain(void)1210 tcp_drain(void)
1211 {
1212 struct inpcb *inp;
1213 struct tcpcb *tp;
1214
1215 mutex_enter(softnet_lock);
1216 KERNEL_LOCK(1, NULL);
1217
1218 /*
1219 * Free the sequence queue of all TCP connections.
1220 */
1221 TAILQ_FOREACH(inp, &tcbtable.inpt_queue, inp_queue) {
1222 tp = intotcpcb(inp);
1223 if (tp != NULL) {
1224 /*
1225 * If the tcpcb is already busy,
1226 * just bail out now.
1227 */
1228 if (tcp_reass_lock_try(tp) == 0)
1229 continue;
1230 if (tcp_freeq(tp))
1231 TCP_STATINC(TCP_STAT_CONNSDRAINED);
1232 TCP_REASS_UNLOCK(tp);
1233 }
1234 }
1235
1236 KERNEL_UNLOCK_ONE(NULL);
1237 mutex_exit(softnet_lock);
1238 }
1239
1240 /*
1241 * Notify a tcp user of an asynchronous error;
1242 * store error as soft error, but wake up user
1243 * (for now, won't do anything until can select for soft error).
1244 */
1245 void
tcp_notify(struct inpcb * inp,int error)1246 tcp_notify(struct inpcb *inp, int error)
1247 {
1248 struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb;
1249 struct socket *so = inp->inp_socket;
1250
1251 /*
1252 * Ignore some errors if we are hooked up.
1253 * If connection hasn't completed, has retransmitted several times,
1254 * and receives a second error, give up now. This is better
1255 * than waiting a long time to establish a connection that
1256 * can never complete.
1257 */
1258 if (tp->t_state == TCPS_ESTABLISHED &&
1259 (error == EHOSTUNREACH || error == ENETUNREACH ||
1260 error == EHOSTDOWN)) {
1261 return;
1262 } else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 &&
1263 tp->t_rxtshift > 3 && tp->t_softerror)
1264 so->so_error = error;
1265 else
1266 tp->t_softerror = error;
1267 cv_broadcast(&so->so_cv);
1268 sorwakeup(so);
1269 sowwakeup(so);
1270 }
1271
1272 #ifdef INET6
1273 void *
tcp6_ctlinput(int cmd,const struct sockaddr * sa,void * d)1274 tcp6_ctlinput(int cmd, const struct sockaddr *sa, void *d)
1275 {
1276 struct tcphdr th;
1277 void (*notify)(struct inpcb *, int) = tcp_notify;
1278 int nmatch;
1279 struct ip6_hdr *ip6;
1280 const struct sockaddr_in6 *sa6_src = NULL;
1281 const struct sockaddr_in6 *sa6 = (const struct sockaddr_in6 *)sa;
1282 struct mbuf *m;
1283 int off;
1284
1285 if (sa->sa_family != AF_INET6 ||
1286 sa->sa_len != sizeof(struct sockaddr_in6))
1287 return NULL;
1288 if ((unsigned)cmd >= PRC_NCMDS)
1289 return NULL;
1290 else if (cmd == PRC_QUENCH) {
1291 /*
1292 * Don't honor ICMP Source Quench messages meant for
1293 * TCP connections.
1294 */
1295 return NULL;
1296 } else if (PRC_IS_REDIRECT(cmd))
1297 notify = in6pcb_rtchange, d = NULL;
1298 else if (cmd == PRC_MSGSIZE)
1299 ; /* special code is present, see below */
1300 else if (cmd == PRC_HOSTDEAD)
1301 d = NULL;
1302 else if (inet6ctlerrmap[cmd] == 0)
1303 return NULL;
1304
1305 /* if the parameter is from icmp6, decode it. */
1306 if (d != NULL) {
1307 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
1308 m = ip6cp->ip6c_m;
1309 ip6 = ip6cp->ip6c_ip6;
1310 off = ip6cp->ip6c_off;
1311 sa6_src = ip6cp->ip6c_src;
1312 } else {
1313 m = NULL;
1314 ip6 = NULL;
1315 sa6_src = &sa6_any;
1316 off = 0;
1317 }
1318
1319 if (ip6) {
1320 /* check if we can safely examine src and dst ports */
1321 if (m->m_pkthdr.len < off + sizeof(th)) {
1322 if (cmd == PRC_MSGSIZE)
1323 icmp6_mtudisc_update((struct ip6ctlparam *)d, 0);
1324 return NULL;
1325 }
1326
1327 memset(&th, 0, sizeof(th));
1328 m_copydata(m, off, sizeof(th), (void *)&th);
1329
1330 if (cmd == PRC_MSGSIZE) {
1331 int valid = 0;
1332
1333 /*
1334 * Check to see if we have a valid TCP connection
1335 * corresponding to the address in the ICMPv6 message
1336 * payload.
1337 */
1338 if (in6pcb_lookup(&tcbtable, &sa6->sin6_addr,
1339 th.th_dport,
1340 (const struct in6_addr *)&sa6_src->sin6_addr,
1341 th.th_sport, 0, 0))
1342 valid++;
1343
1344 /*
1345 * Depending on the value of "valid" and routing table
1346 * size (mtudisc_{hi,lo}wat), we will:
1347 * - recalculate the new MTU and create the
1348 * corresponding routing entry, or
1349 * - ignore the MTU change notification.
1350 */
1351 icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
1352
1353 /*
1354 * no need to call in6pcb_notify, it should have been
1355 * called via callback if necessary
1356 */
1357 return NULL;
1358 }
1359
1360 nmatch = in6pcb_notify(&tcbtable, sa, th.th_dport,
1361 (const struct sockaddr *)sa6_src, th.th_sport, cmd, NULL, notify);
1362 if (nmatch == 0 && syn_cache_count &&
1363 (inet6ctlerrmap[cmd] == EHOSTUNREACH ||
1364 inet6ctlerrmap[cmd] == ENETUNREACH ||
1365 inet6ctlerrmap[cmd] == EHOSTDOWN))
1366 syn_cache_unreach((const struct sockaddr *)sa6_src,
1367 sa, &th);
1368 } else {
1369 (void) in6pcb_notify(&tcbtable, sa, 0,
1370 (const struct sockaddr *)sa6_src, 0, cmd, NULL, notify);
1371 }
1372
1373 return NULL;
1374 }
1375 #endif
1376
1377 /* assumes that ip header and tcp header are contiguous on mbuf */
1378 void *
tcp_ctlinput(int cmd,const struct sockaddr * sa,void * v)1379 tcp_ctlinput(int cmd, const struct sockaddr *sa, void *v)
1380 {
1381 struct ip *ip = v;
1382 struct tcphdr *th;
1383 struct icmp *icp;
1384 extern const int inetctlerrmap[];
1385 void (*notify)(struct inpcb *, int) = tcp_notify;
1386 int errno;
1387 int nmatch;
1388 struct tcpcb *tp;
1389 u_int mtu;
1390 tcp_seq seq;
1391 struct inpcb *inp;
1392 #ifdef INET6
1393 struct in6_addr src6, dst6;
1394 #endif
1395
1396 if (sa->sa_family != AF_INET ||
1397 sa->sa_len != sizeof(struct sockaddr_in))
1398 return NULL;
1399 if ((unsigned)cmd >= PRC_NCMDS)
1400 return NULL;
1401 errno = inetctlerrmap[cmd];
1402 if (cmd == PRC_QUENCH)
1403 /*
1404 * Don't honor ICMP Source Quench messages meant for
1405 * TCP connections.
1406 */
1407 return NULL;
1408 else if (PRC_IS_REDIRECT(cmd))
1409 notify = inpcb_rtchange, ip = 0;
1410 else if (cmd == PRC_MSGSIZE && ip && ip->ip_v == 4) {
1411 /*
1412 * Check to see if we have a valid TCP connection
1413 * corresponding to the address in the ICMP message
1414 * payload.
1415 *
1416 * Boundary check is made in icmp_input(), with ICMP_ADVLENMIN.
1417 */
1418 th = (struct tcphdr *)((char *)ip + (ip->ip_hl << 2));
1419 #ifdef INET6
1420 in6_in_2_v4mapin6(&ip->ip_src, &src6);
1421 in6_in_2_v4mapin6(&ip->ip_dst, &dst6);
1422 #endif
1423 if ((inp = inpcb_lookup(&tcbtable, ip->ip_dst,
1424 th->th_dport, ip->ip_src, th->th_sport, 0)) != NULL)
1425 ;
1426 #ifdef INET6
1427 else if ((inp = in6pcb_lookup(&tcbtable, &dst6,
1428 th->th_dport, &src6, th->th_sport, 0, 0)) != NULL)
1429 ;
1430 #endif
1431 else
1432 return NULL;
1433
1434 /*
1435 * Now that we've validated that we are actually communicating
1436 * with the host indicated in the ICMP message, locate the
1437 * ICMP header, recalculate the new MTU, and create the
1438 * corresponding routing entry.
1439 */
1440 icp = (struct icmp *)((char *)ip -
1441 offsetof(struct icmp, icmp_ip));
1442 tp = intotcpcb(inp);
1443 if (tp == NULL)
1444 return NULL;
1445 seq = ntohl(th->th_seq);
1446 if (SEQ_LT(seq, tp->snd_una) || SEQ_GT(seq, tp->snd_max))
1447 return NULL;
1448 /*
1449 * If the ICMP message advertises a Next-Hop MTU
1450 * equal or larger than the maximum packet size we have
1451 * ever sent, drop the message.
1452 */
1453 mtu = (u_int)ntohs(icp->icmp_nextmtu);
1454 if (mtu >= tp->t_pmtud_mtu_sent)
1455 return NULL;
1456 if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) {
1457 /*
1458 * Calculate new MTU, and create corresponding
1459 * route (traditional PMTUD).
1460 */
1461 tp->t_flags &= ~TF_PMTUD_PEND;
1462 icmp_mtudisc(icp, ip->ip_dst);
1463 } else {
1464 /*
1465 * Record the information got in the ICMP
1466 * message; act on it later.
1467 * If we had already recorded an ICMP message,
1468 * replace the old one only if the new message
1469 * refers to an older TCP segment
1470 */
1471 if (tp->t_flags & TF_PMTUD_PEND) {
1472 if (SEQ_LT(tp->t_pmtud_th_seq, seq))
1473 return NULL;
1474 } else
1475 tp->t_flags |= TF_PMTUD_PEND;
1476 tp->t_pmtud_th_seq = seq;
1477 tp->t_pmtud_nextmtu = icp->icmp_nextmtu;
1478 tp->t_pmtud_ip_len = icp->icmp_ip.ip_len;
1479 tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl;
1480 }
1481 return NULL;
1482 } else if (cmd == PRC_HOSTDEAD)
1483 ip = 0;
1484 else if (errno == 0)
1485 return NULL;
1486 if (ip && ip->ip_v == 4 && sa->sa_family == AF_INET) {
1487 th = (struct tcphdr *)((char *)ip + (ip->ip_hl << 2));
1488 nmatch = inpcb_notify(&tcbtable, satocsin(sa)->sin_addr,
1489 th->th_dport, ip->ip_src, th->th_sport, errno, notify);
1490 if (nmatch == 0 && syn_cache_count &&
1491 (inetctlerrmap[cmd] == EHOSTUNREACH ||
1492 inetctlerrmap[cmd] == ENETUNREACH ||
1493 inetctlerrmap[cmd] == EHOSTDOWN)) {
1494 struct sockaddr_in sin;
1495 memset(&sin, 0, sizeof(sin));
1496 sin.sin_len = sizeof(sin);
1497 sin.sin_family = AF_INET;
1498 sin.sin_port = th->th_sport;
1499 sin.sin_addr = ip->ip_src;
1500 syn_cache_unreach((struct sockaddr *)&sin, sa, th);
1501 }
1502
1503 /* XXX mapped address case */
1504 } else
1505 inpcb_notifyall(&tcbtable, satocsin(sa)->sin_addr, errno,
1506 notify);
1507 return NULL;
1508 }
1509
1510 /*
1511 * When a source quench is received, we are being notified of congestion.
1512 * Close the congestion window down to the Loss Window (one segment).
1513 * We will gradually open it again as we proceed.
1514 */
1515 void
tcp_quench(struct inpcb * inp)1516 tcp_quench(struct inpcb *inp)
1517 {
1518 struct tcpcb *tp = intotcpcb(inp);
1519
1520 if (tp) {
1521 tp->snd_cwnd = tp->t_segsz;
1522 tp->t_bytes_acked = 0;
1523 }
1524 }
1525
1526 /*
1527 * Path MTU Discovery handlers.
1528 */
1529 void
tcp_mtudisc_callback(struct in_addr faddr)1530 tcp_mtudisc_callback(struct in_addr faddr)
1531 {
1532 #ifdef INET6
1533 struct in6_addr in6;
1534 #endif
1535
1536 inpcb_notifyall(&tcbtable, faddr, EMSGSIZE, tcp_mtudisc);
1537 #ifdef INET6
1538 in6_in_2_v4mapin6(&faddr, &in6);
1539 tcp6_mtudisc_callback(&in6);
1540 #endif
1541 }
1542
1543 /*
1544 * On receipt of path MTU corrections, flush old route and replace it
1545 * with the new one. Retransmit all unacknowledged packets, to ensure
1546 * that all packets will be received.
1547 */
1548 void
tcp_mtudisc(struct inpcb * inp,int errno)1549 tcp_mtudisc(struct inpcb *inp, int errno)
1550 {
1551 struct tcpcb *tp = intotcpcb(inp);
1552 struct rtentry *rt;
1553
1554 if (tp == NULL)
1555 return;
1556
1557 rt = inpcb_rtentry(inp);
1558 if (rt != NULL) {
1559 /*
1560 * If this was not a host route, remove and realloc.
1561 */
1562 if ((rt->rt_flags & RTF_HOST) == 0) {
1563 inpcb_rtentry_unref(rt, inp);
1564 inpcb_rtchange(inp, errno);
1565 if ((rt = inpcb_rtentry(inp)) == NULL)
1566 return;
1567 }
1568
1569 /*
1570 * Slow start out of the error condition. We
1571 * use the MTU because we know it's smaller
1572 * than the previously transmitted segment.
1573 *
1574 * Note: This is more conservative than the
1575 * suggestion in draft-floyd-incr-init-win-03.
1576 */
1577 if (rt->rt_rmx.rmx_mtu != 0)
1578 tp->snd_cwnd =
1579 TCP_INITIAL_WINDOW(tcp_init_win,
1580 rt->rt_rmx.rmx_mtu);
1581 inpcb_rtentry_unref(rt, inp);
1582 }
1583
1584 /*
1585 * Resend unacknowledged packets.
1586 */
1587 tp->snd_nxt = tp->sack_newdata = tp->snd_una;
1588 tcp_output(tp);
1589 }
1590
1591 #ifdef INET6
1592 /*
1593 * Path MTU Discovery handlers.
1594 */
1595 void
tcp6_mtudisc_callback(struct in6_addr * faddr)1596 tcp6_mtudisc_callback(struct in6_addr *faddr)
1597 {
1598 struct sockaddr_in6 sin6;
1599
1600 memset(&sin6, 0, sizeof(sin6));
1601 sin6.sin6_family = AF_INET6;
1602 sin6.sin6_len = sizeof(struct sockaddr_in6);
1603 sin6.sin6_addr = *faddr;
1604 (void) in6pcb_notify(&tcbtable, (struct sockaddr *)&sin6, 0,
1605 (const struct sockaddr *)&sa6_any, 0, PRC_MSGSIZE, NULL, tcp6_mtudisc);
1606 }
1607
1608 void
tcp6_mtudisc(struct inpcb * inp,int errno)1609 tcp6_mtudisc(struct inpcb *inp, int errno)
1610 {
1611 struct tcpcb *tp = intotcpcb(inp);
1612 struct rtentry *rt;
1613
1614 if (tp == NULL)
1615 return;
1616
1617 rt = in6pcb_rtentry(inp);
1618 if (rt != NULL) {
1619 /*
1620 * If this was not a host route, remove and realloc.
1621 */
1622 if ((rt->rt_flags & RTF_HOST) == 0) {
1623 in6pcb_rtentry_unref(rt, inp);
1624 in6pcb_rtchange(inp, errno);
1625 rt = in6pcb_rtentry(inp);
1626 if (rt == NULL)
1627 return;
1628 }
1629
1630 /*
1631 * Slow start out of the error condition. We
1632 * use the MTU because we know it's smaller
1633 * than the previously transmitted segment.
1634 *
1635 * Note: This is more conservative than the
1636 * suggestion in draft-floyd-incr-init-win-03.
1637 */
1638 if (rt->rt_rmx.rmx_mtu != 0) {
1639 tp->snd_cwnd = TCP_INITIAL_WINDOW(tcp_init_win,
1640 rt->rt_rmx.rmx_mtu);
1641 }
1642 in6pcb_rtentry_unref(rt, inp);
1643 }
1644
1645 /*
1646 * Resend unacknowledged packets.
1647 */
1648 tp->snd_nxt = tp->sack_newdata = tp->snd_una;
1649 tcp_output(tp);
1650 }
1651 #endif /* INET6 */
1652
1653 /*
1654 * Compute the MSS to advertise to the peer. Called only during
1655 * the 3-way handshake. If we are the server (peer initiated
1656 * connection), we are called with a pointer to the interface
1657 * on which the SYN packet arrived. If we are the client (we
1658 * initiated connection), we are called with a pointer to the
1659 * interface out which this connection should go.
1660 *
1661 * NOTE: Do not subtract IP option/extension header size nor IPsec
1662 * header size from MSS advertisement. MSS option must hold the maximum
1663 * segment size we can accept, so it must always be:
1664 * max(if mtu) - ip header - tcp header
1665 */
1666 u_long
tcp_mss_to_advertise(const struct ifnet * ifp,int af)1667 tcp_mss_to_advertise(const struct ifnet *ifp, int af)
1668 {
1669 extern u_long in_maxmtu;
1670 u_long mss = 0;
1671 u_long hdrsiz;
1672
1673 /*
1674 * In order to avoid defeating path MTU discovery on the peer,
1675 * we advertise the max MTU of all attached networks as our MSS,
1676 * per RFC 1191, section 3.1.
1677 *
1678 * We provide the option to advertise just the MTU of
1679 * the interface on which we hope this connection will
1680 * be receiving. If we are responding to a SYN, we
1681 * will have a pretty good idea about this, but when
1682 * initiating a connection there is a bit more doubt.
1683 *
1684 * We also need to ensure that loopback has a large enough
1685 * MSS, as the loopback MTU is never included in in_maxmtu.
1686 */
1687
1688 if (ifp != NULL)
1689 switch (af) {
1690 #ifdef INET6
1691 case AF_INET6: /* FALLTHROUGH */
1692 #endif
1693 case AF_INET:
1694 mss = ifp->if_mtu;
1695 break;
1696 }
1697
1698 if (tcp_mss_ifmtu == 0)
1699 switch (af) {
1700 #ifdef INET6
1701 case AF_INET6: /* FALLTHROUGH */
1702 #endif
1703 case AF_INET:
1704 mss = uimax(in_maxmtu, mss);
1705 break;
1706 }
1707
1708 switch (af) {
1709 case AF_INET:
1710 hdrsiz = sizeof(struct ip);
1711 break;
1712 #ifdef INET6
1713 case AF_INET6:
1714 hdrsiz = sizeof(struct ip6_hdr);
1715 break;
1716 #endif
1717 default:
1718 hdrsiz = 0;
1719 break;
1720 }
1721 hdrsiz += sizeof(struct tcphdr);
1722 if (mss > hdrsiz)
1723 mss -= hdrsiz;
1724
1725 mss = uimax(tcp_mssdflt, mss);
1726 return (mss);
1727 }
1728
1729 /*
1730 * Set connection variables based on the peer's advertised MSS.
1731 * We are passed the TCPCB for the actual connection. If we
1732 * are the server, we are called by the compressed state engine
1733 * when the 3-way handshake is complete. If we are the client,
1734 * we are called when we receive the SYN,ACK from the server.
1735 *
1736 * NOTE: Our advertised MSS value must be initialized in the TCPCB
1737 * before this routine is called!
1738 */
1739 void
tcp_mss_from_peer(struct tcpcb * tp,int offer)1740 tcp_mss_from_peer(struct tcpcb *tp, int offer)
1741 {
1742 struct socket *so;
1743 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
1744 struct rtentry *rt;
1745 #endif
1746 u_long bufsize;
1747 int mss;
1748
1749 KASSERT(tp->t_inpcb != NULL);
1750
1751 so = NULL;
1752 rt = NULL;
1753
1754 so = tp->t_inpcb->inp_socket;
1755 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
1756 rt = inpcb_rtentry(tp->t_inpcb);
1757 #endif
1758
1759 /*
1760 * As per RFC1122, use the default MSS value, unless they
1761 * sent us an offer. Do not accept offers less than 256 bytes.
1762 */
1763 mss = tcp_mssdflt;
1764 if (offer)
1765 mss = offer;
1766 mss = uimax(mss, 256); /* sanity */
1767 tp->t_peermss = mss;
1768 mss -= tcp_optlen(tp);
1769 if (tp->t_inpcb->inp_af == AF_INET)
1770 mss -= ip_optlen(tp->t_inpcb);
1771 #ifdef INET6
1772 if (tp->t_inpcb->inp_af == AF_INET6)
1773 mss -= ip6_optlen(tp->t_inpcb);
1774 #endif
1775 /*
1776 * XXX XXX What if mss goes negative or zero? This can happen if a
1777 * socket has large IPv6 options. We crash below.
1778 */
1779
1780 /*
1781 * If there's a pipesize, change the socket buffer to that size.
1782 * Make the socket buffer an integral number of MSS units. If
1783 * the MSS is larger than the socket buffer, artificially decrease
1784 * the MSS.
1785 */
1786 #ifdef RTV_SPIPE
1787 if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0)
1788 bufsize = rt->rt_rmx.rmx_sendpipe;
1789 else
1790 #endif
1791 {
1792 KASSERT(so != NULL);
1793 bufsize = so->so_snd.sb_hiwat;
1794 }
1795 if (bufsize < mss)
1796 mss = bufsize;
1797 else {
1798 bufsize = roundup(bufsize, mss);
1799 if (bufsize > sb_max)
1800 bufsize = sb_max;
1801 (void) sbreserve(&so->so_snd, bufsize, so);
1802 }
1803 tp->t_segsz = mss;
1804
1805 #ifdef RTV_SSTHRESH
1806 if (rt != NULL && rt->rt_rmx.rmx_ssthresh) {
1807 /*
1808 * There's some sort of gateway or interface buffer
1809 * limit on the path. Use this to set the slow
1810 * start threshold, but set the threshold to no less
1811 * than 2 * MSS.
1812 */
1813 tp->snd_ssthresh = uimax(2 * mss, rt->rt_rmx.rmx_ssthresh);
1814 }
1815 #endif
1816 #if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
1817 inpcb_rtentry_unref(rt, tp->t_inpcb);
1818 #endif
1819 }
1820
1821 /*
1822 * Processing necessary when a TCP connection is established.
1823 */
1824 void
tcp_established(struct tcpcb * tp)1825 tcp_established(struct tcpcb *tp)
1826 {
1827 struct socket *so;
1828 #ifdef RTV_RPIPE
1829 struct rtentry *rt;
1830 #endif
1831 u_long bufsize;
1832
1833 KASSERT(tp->t_inpcb != NULL);
1834
1835 so = NULL;
1836 rt = NULL;
1837
1838 /* This is a while() to reduce the dreadful stairstepping below */
1839 while (tp->t_inpcb->inp_af == AF_INET) {
1840 so = tp->t_inpcb->inp_socket;
1841 #if defined(RTV_RPIPE)
1842 rt = inpcb_rtentry(tp->t_inpcb);
1843 #endif
1844 if (__predict_true(tcp_msl_enable)) {
1845 if (in4p_laddr(tp->t_inpcb).s_addr == INADDR_LOOPBACK) {
1846 tp->t_msl = tcp_msl_loop ? tcp_msl_loop : (TCPTV_MSL >> 2);
1847 break;
1848 }
1849
1850 if (__predict_false(tcp_rttlocal)) {
1851 /* This may be adjusted by tcp_input */
1852 tp->t_msl = tcp_msl_local ? tcp_msl_local : (TCPTV_MSL >> 1);
1853 break;
1854 }
1855 if (in_localaddr(in4p_faddr(tp->t_inpcb))) {
1856 tp->t_msl = tcp_msl_local ? tcp_msl_local : (TCPTV_MSL >> 1);
1857 break;
1858 }
1859 }
1860 tp->t_msl = tcp_msl_remote ? tcp_msl_remote : TCPTV_MSL;
1861 break;
1862 }
1863
1864 /* Clamp to a reasonable range. */
1865 tp->t_msl = MIN(tp->t_msl, TCP_MAXMSL);
1866
1867 #ifdef INET6
1868 while (tp->t_inpcb->inp_af == AF_INET6) {
1869 so = tp->t_inpcb->inp_socket;
1870 #if defined(RTV_RPIPE)
1871 rt = in6pcb_rtentry(tp->t_inpcb);
1872 #endif
1873 if (__predict_true(tcp_msl_enable)) {
1874 extern const struct in6_addr in6addr_loopback;
1875
1876 if (IN6_ARE_ADDR_EQUAL(&in6p_laddr(tp->t_inpcb),
1877 &in6addr_loopback)) {
1878 tp->t_msl = tcp_msl_loop ? tcp_msl_loop : (TCPTV_MSL >> 2);
1879 break;
1880 }
1881
1882 if (__predict_false(tcp_rttlocal)) {
1883 /* This may be adjusted by tcp_input */
1884 tp->t_msl = tcp_msl_local ? tcp_msl_local : (TCPTV_MSL >> 1);
1885 break;
1886 }
1887 if (in6_localaddr(&in6p_faddr(tp->t_inpcb))) {
1888 tp->t_msl = tcp_msl_local ? tcp_msl_local : (TCPTV_MSL >> 1);
1889 break;
1890 }
1891 }
1892 tp->t_msl = tcp_msl_remote ? tcp_msl_remote : TCPTV_MSL;
1893 break;
1894 }
1895
1896 /* Clamp to a reasonable range. */
1897 tp->t_msl = MIN(tp->t_msl, TCP_MAXMSL);
1898 #endif
1899
1900 tp->t_state = TCPS_ESTABLISHED;
1901 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle);
1902
1903 #ifdef RTV_RPIPE
1904 if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0)
1905 bufsize = rt->rt_rmx.rmx_recvpipe;
1906 else
1907 #endif
1908 {
1909 KASSERT(so != NULL);
1910 bufsize = so->so_rcv.sb_hiwat;
1911 }
1912 if (bufsize > tp->t_ourmss) {
1913 bufsize = roundup(bufsize, tp->t_ourmss);
1914 if (bufsize > sb_max)
1915 bufsize = sb_max;
1916 (void) sbreserve(&so->so_rcv, bufsize, so);
1917 }
1918 #ifdef RTV_RPIPE
1919 inpcb_rtentry_unref(rt, tp->t_inpcb);
1920 #endif
1921 }
1922
1923 /*
1924 * Check if there's an initial rtt or rttvar. Convert from the
1925 * route-table units to scaled multiples of the slow timeout timer.
1926 * Called only during the 3-way handshake.
1927 */
1928 void
tcp_rmx_rtt(struct tcpcb * tp)1929 tcp_rmx_rtt(struct tcpcb *tp)
1930 {
1931 #ifdef RTV_RTT
1932 struct rtentry *rt = NULL;
1933 int rtt;
1934
1935 KASSERT(tp->t_inpcb != NULL);
1936
1937 rt = inpcb_rtentry(tp->t_inpcb);
1938 if (rt == NULL)
1939 return;
1940
1941 if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) {
1942 /*
1943 * XXX The lock bit for MTU indicates that the value
1944 * is also a minimum value; this is subject to time.
1945 */
1946 if (rt->rt_rmx.rmx_locks & RTV_RTT)
1947 TCPT_RANGESET(tp->t_rttmin,
1948 rtt / (RTM_RTTUNIT / PR_SLOWHZ),
1949 TCPTV_MIN, TCPTV_REXMTMAX);
1950 tp->t_srtt = rtt /
1951 ((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2));
1952 if (rt->rt_rmx.rmx_rttvar) {
1953 tp->t_rttvar = rt->rt_rmx.rmx_rttvar /
1954 ((RTM_RTTUNIT / PR_SLOWHZ) >>
1955 (TCP_RTTVAR_SHIFT + 2));
1956 } else {
1957 /* Default variation is +- 1 rtt */
1958 tp->t_rttvar =
1959 tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT);
1960 }
1961 TCPT_RANGESET(tp->t_rxtcur,
1962 ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2),
1963 tp->t_rttmin, TCPTV_REXMTMAX);
1964 }
1965 inpcb_rtentry_unref(rt, tp->t_inpcb);
1966 #endif
1967 }
1968
1969 tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */
1970
1971 /*
1972 * Get a new sequence value given a tcp control block
1973 */
1974 tcp_seq
tcp_new_iss(struct tcpcb * tp)1975 tcp_new_iss(struct tcpcb *tp)
1976 {
1977
1978 if (tp->t_inpcb->inp_af == AF_INET) {
1979 return tcp_new_iss1(&in4p_laddr(tp->t_inpcb),
1980 &in4p_faddr(tp->t_inpcb), tp->t_inpcb->inp_lport,
1981 tp->t_inpcb->inp_fport, sizeof(in4p_laddr(tp->t_inpcb)));
1982 }
1983 #ifdef INET6
1984 if (tp->t_inpcb->inp_af == AF_INET6) {
1985 return tcp_new_iss1(&in6p_laddr(tp->t_inpcb),
1986 &in6p_faddr(tp->t_inpcb), tp->t_inpcb->inp_lport,
1987 tp->t_inpcb->inp_fport, sizeof(in6p_laddr(tp->t_inpcb)));
1988 }
1989 #endif
1990
1991 panic("tcp_new_iss: unreachable");
1992 }
1993
1994 static u_int8_t tcp_iss_secret[16]; /* 128 bits; should be plenty */
1995
1996 /*
1997 * Initialize RFC 1948 ISS Secret
1998 */
1999 static int
tcp_iss_secret_init(void)2000 tcp_iss_secret_init(void)
2001 {
2002 cprng_strong(kern_cprng,
2003 tcp_iss_secret, sizeof(tcp_iss_secret), 0);
2004
2005 return 0;
2006 }
2007
2008 /*
2009 * This routine actually generates a new TCP initial sequence number.
2010 */
2011 tcp_seq
tcp_new_iss1(void * laddr,void * faddr,u_int16_t lport,u_int16_t fport,size_t addrsz)2012 tcp_new_iss1(void *laddr, void *faddr, u_int16_t lport, u_int16_t fport,
2013 size_t addrsz)
2014 {
2015 tcp_seq tcp_iss;
2016
2017 if (tcp_do_rfc1948) {
2018 MD5_CTX ctx;
2019 u_int8_t hash[16]; /* XXX MD5 knowledge */
2020 static ONCE_DECL(tcp_iss_secret_control);
2021
2022 /*
2023 * If we haven't been here before, initialize our cryptographic
2024 * hash secret.
2025 */
2026 RUN_ONCE(&tcp_iss_secret_control, tcp_iss_secret_init);
2027
2028 /*
2029 * Compute the base value of the ISS. It is a hash
2030 * of (saddr, sport, daddr, dport, secret).
2031 */
2032 MD5Init(&ctx);
2033
2034 MD5Update(&ctx, (u_char *) laddr, addrsz);
2035 MD5Update(&ctx, (u_char *) &lport, sizeof(lport));
2036
2037 MD5Update(&ctx, (u_char *) faddr, addrsz);
2038 MD5Update(&ctx, (u_char *) &fport, sizeof(fport));
2039
2040 MD5Update(&ctx, tcp_iss_secret, sizeof(tcp_iss_secret));
2041
2042 MD5Final(hash, &ctx);
2043
2044 memcpy(&tcp_iss, hash, sizeof(tcp_iss));
2045
2046 #ifdef TCPISS_DEBUG
2047 printf("ISS hash 0x%08x, ", tcp_iss);
2048 #endif
2049 } else {
2050 /*
2051 * Randomize.
2052 */
2053 tcp_iss = cprng_fast32() & TCP_ISS_RANDOM_MASK;
2054 #ifdef TCPISS_DEBUG
2055 printf("ISS random 0x%08x, ", tcp_iss);
2056 #endif
2057 }
2058
2059 /*
2060 * Add the offset in to the computed value.
2061 */
2062 tcp_iss += tcp_iss_seq;
2063 #ifdef TCPISS_DEBUG
2064 printf("ISS %08x\n", tcp_iss);
2065 #endif
2066 return tcp_iss;
2067 }
2068
2069 #if defined(IPSEC)
2070 /* compute ESP/AH header size for TCP, including outer IP header. */
2071 size_t
ipsec4_hdrsiz_tcp(struct tcpcb * tp)2072 ipsec4_hdrsiz_tcp(struct tcpcb *tp)
2073 {
2074 struct inpcb *inp;
2075 size_t hdrsiz;
2076
2077 /* XXX mapped addr case (tp->t_inpcb) */
2078 if (!tp || !tp->t_template || !(inp = tp->t_inpcb))
2079 return 0;
2080 switch (tp->t_family) {
2081 case AF_INET:
2082 /* XXX: should use correct direction. */
2083 hdrsiz = ipsec_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp);
2084 break;
2085 default:
2086 hdrsiz = 0;
2087 break;
2088 }
2089
2090 return hdrsiz;
2091 }
2092
2093 #ifdef INET6
2094 size_t
ipsec6_hdrsiz_tcp(struct tcpcb * tp)2095 ipsec6_hdrsiz_tcp(struct tcpcb *tp)
2096 {
2097 struct inpcb *inp;
2098 size_t hdrsiz;
2099
2100 if (!tp || !tp->t_template || !(inp = tp->t_inpcb))
2101 return 0;
2102 switch (tp->t_family) {
2103 case AF_INET6:
2104 /* XXX: should use correct direction. */
2105 hdrsiz = ipsec_hdrsiz(tp->t_template, IPSEC_DIR_OUTBOUND, inp);
2106 break;
2107 case AF_INET:
2108 /* mapped address case - tricky */
2109 default:
2110 hdrsiz = 0;
2111 break;
2112 }
2113
2114 return hdrsiz;
2115 }
2116 #endif
2117 #endif /*IPSEC*/
2118
2119 /*
2120 * Determine the length of the TCP options for this connection.
2121 *
2122 * XXX: What do we do for SACK, when we add that? Just reserve
2123 * all of the space? Otherwise we can't exactly be incrementing
2124 * cwnd by an amount that varies depending on the amount we last
2125 * had to SACK!
2126 */
2127
2128 u_int
tcp_optlen(struct tcpcb * tp)2129 tcp_optlen(struct tcpcb *tp)
2130 {
2131 u_int optlen;
2132
2133 optlen = 0;
2134 if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) ==
2135 (TF_REQ_TSTMP | TF_RCVD_TSTMP))
2136 optlen += TCPOLEN_TSTAMP_APPA;
2137
2138 #ifdef TCP_SIGNATURE
2139 if (tp->t_flags & TF_SIGNATURE)
2140 optlen += TCPOLEN_SIGLEN;
2141 #endif
2142
2143 return optlen;
2144 }
2145
2146 u_int
tcp_hdrsz(struct tcpcb * tp)2147 tcp_hdrsz(struct tcpcb *tp)
2148 {
2149 u_int hlen;
2150
2151 switch (tp->t_family) {
2152 #ifdef INET6
2153 case AF_INET6:
2154 hlen = sizeof(struct ip6_hdr);
2155 break;
2156 #endif
2157 case AF_INET:
2158 hlen = sizeof(struct ip);
2159 break;
2160 default:
2161 hlen = 0;
2162 break;
2163 }
2164 hlen += sizeof(struct tcphdr);
2165
2166 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
2167 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP)
2168 hlen += TCPOLEN_TSTAMP_APPA;
2169 #ifdef TCP_SIGNATURE
2170 if (tp->t_flags & TF_SIGNATURE)
2171 hlen += TCPOLEN_SIGLEN;
2172 #endif
2173 return hlen;
2174 }
2175
2176 void
tcp_statinc(u_int stat)2177 tcp_statinc(u_int stat)
2178 {
2179
2180 KASSERT(stat < TCP_NSTATS);
2181 TCP_STATINC(stat);
2182 }
2183
2184 void
tcp_statadd(u_int stat,uint64_t val)2185 tcp_statadd(u_int stat, uint64_t val)
2186 {
2187
2188 KASSERT(stat < TCP_NSTATS);
2189 TCP_STATADD(stat, val);
2190 }
2191