1 /*-
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: releng/11.0/sys/netinet/tcp_subr.c 303966 2016-08-11 19:05:47Z gallatin $");
34
35 #include "opt_compat.h"
36 #include "opt_inet.h"
37 #include "opt_inet6.h"
38 #include "opt_ipsec.h"
39 #include "opt_tcpdebug.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/callout.h>
44 #include <sys/eventhandler.h>
45 #include <sys/hhook.h>
46 #include <sys/kernel.h>
47 #include <sys/khelp.h>
48 #include <sys/sysctl.h>
49 #include <sys/jail.h>
50 #include <sys/malloc.h>
51 #include <sys/refcount.h>
52 #include <sys/mbuf.h>
53 #ifdef INET6
54 #include <sys/domain.h>
55 #endif
56 #include <sys/priv.h>
57 #include <sys/proc.h>
58 #include <sys/sdt.h>
59 #include <sys/socket.h>
60 #include <sys/socketvar.h>
61 #include <sys/protosw.h>
62 #include <sys/random.h>
63
64 #include <vm/uma.h>
65
66 #include <net/route.h>
67 #include <net/if.h>
68 #include <net/if_var.h>
69 #include <net/vnet.h>
70
71 #include <netinet/in.h>
72 #include <netinet/in_fib.h>
73 #include <netinet/in_kdtrace.h>
74 #include <netinet/in_pcb.h>
75 #include <netinet/in_systm.h>
76 #include <netinet/in_var.h>
77 #include <netinet/ip.h>
78 #include <netinet/ip_icmp.h>
79 #include <netinet/ip_var.h>
80 #ifdef INET6
81 #include <netinet/ip6.h>
82 #include <netinet6/in6_fib.h>
83 #include <netinet6/in6_pcb.h>
84 #include <netinet6/ip6_var.h>
85 #include <netinet6/scope6_var.h>
86 #include <netinet6/nd6.h>
87 #endif
88
89 #ifdef TCP_RFC7413
90 #include <netinet/tcp_fastopen.h>
91 #endif
92 #include <netinet/tcp.h>
93 #include <netinet/tcp_fsm.h>
94 #include <netinet/tcp_seq.h>
95 #include <netinet/tcp_timer.h>
96 #include <netinet/tcp_var.h>
97 #include <netinet/tcp_syncache.h>
98 #include <netinet/cc/cc.h>
99 #ifdef INET6
100 #include <netinet6/tcp6_var.h>
101 #endif
102 #include <netinet/tcpip.h>
103 #ifdef TCPPCAP
104 #include <netinet/tcp_pcap.h>
105 #endif
106 #ifdef TCPDEBUG
107 #include <netinet/tcp_debug.h>
108 #endif
109 #ifdef INET6
110 #include <netinet6/ip6protosw.h>
111 #endif
112 #ifdef TCP_OFFLOAD
113 #include <netinet/tcp_offload.h>
114 #endif
115
116 #ifdef IPSEC
117 #include <netipsec/ipsec.h>
118 #include <netipsec/xform.h>
119 #ifdef INET6
120 #include <netipsec/ipsec6.h>
121 #endif
122 #include <netipsec/key.h>
123 #include <sys/syslog.h>
124 #endif /*IPSEC*/
125
126 #include <machine/in_cksum.h>
127 #include <sys/md5.h>
128
129 #include <security/mac/mac_framework.h>
130
131 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS;
132 #ifdef INET6
133 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS;
134 #endif
135
136 struct rwlock tcp_function_lock;
137
138 static int
139 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
140 {
141 int error, new;
142
143 new = V_tcp_mssdflt;
144 error = sysctl_handle_int(oidp, &new, 0, req);
145 if (error == 0 && req->newptr) {
146 if (new < TCP_MINMSS)
147 error = EINVAL;
148 else
149 V_tcp_mssdflt = new;
150 }
151 return (error);
152 }
153
154 SYSCTL_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
155 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW, &VNET_NAME(tcp_mssdflt), 0,
156 &sysctl_net_inet_tcp_mss_check, "I",
157 "Default TCP Maximum Segment Size");
158
159 #ifdef INET6
160 static int
161 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS)
162 {
163 int error, new;
164
165 new = V_tcp_v6mssdflt;
166 error = sysctl_handle_int(oidp, &new, 0, req);
167 if (error == 0 && req->newptr) {
168 if (new < TCP_MINMSS)
169 error = EINVAL;
170 else
171 V_tcp_v6mssdflt = new;
172 }
173 return (error);
174 }
175
176 SYSCTL_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
177 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW, &VNET_NAME(tcp_v6mssdflt), 0,
178 &sysctl_net_inet_tcp_mss_v6_check, "I",
179 "Default TCP Maximum Segment Size for IPv6");
180 #endif /* INET6 */
181
182 /*
183 * Minimum MSS we accept and use. This prevents DoS attacks where
184 * we are forced to a ridiculous low MSS like 20 and send hundreds
185 * of packets instead of one. The effect scales with the available
186 * bandwidth and quickly saturates the CPU and network interface
187 * with packet generation and sending. Set to zero to disable MINMSS
188 * checking. This setting prevents us from sending too small packets.
189 */
190 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS;
191 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_VNET | CTLFLAG_RW,
192 &VNET_NAME(tcp_minmss), 0,
193 "Minimum TCP Maximum Segment Size");
194
195 VNET_DEFINE(int, tcp_do_rfc1323) = 1;
196 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_VNET | CTLFLAG_RW,
197 &VNET_NAME(tcp_do_rfc1323), 0,
198 "Enable rfc1323 (high performance TCP) extensions");
199
200 static int tcp_log_debug = 0;
201 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW,
202 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments");
203
204 static int tcp_tcbhashsize;
205 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
206 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
207
208 static int do_tcpdrain = 1;
209 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
210 "Enable tcp_drain routine for extra help when low on mbufs");
211
212 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_VNET | CTLFLAG_RD,
213 &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
214
215 static VNET_DEFINE(int, icmp_may_rst) = 1;
216 #define V_icmp_may_rst VNET(icmp_may_rst)
217 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_VNET | CTLFLAG_RW,
218 &VNET_NAME(icmp_may_rst), 0,
219 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
220
221 static VNET_DEFINE(int, tcp_isn_reseed_interval) = 0;
222 #define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval)
223 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_VNET | CTLFLAG_RW,
224 &VNET_NAME(tcp_isn_reseed_interval), 0,
225 "Seconds between reseeding of ISN secret");
226
227 static int tcp_soreceive_stream;
228 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
229 &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
230
231 #ifdef TCP_SIGNATURE
232 static int tcp_sig_checksigs = 1;
233 SYSCTL_INT(_net_inet_tcp, OID_AUTO, signature_verify_input, CTLFLAG_RW,
234 &tcp_sig_checksigs, 0, "Verify RFC2385 digests on inbound traffic");
235 #endif
236
237 VNET_DEFINE(uma_zone_t, sack_hole_zone);
238 #define V_sack_hole_zone VNET(sack_hole_zone)
239
240 VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]);
241
242 static struct inpcb *tcp_notify(struct inpcb *, int);
243 static struct inpcb *tcp_mtudisc_notify(struct inpcb *, int);
244 static void tcp_mtudisc(struct inpcb *, int);
245 static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th,
246 void *ip4hdr, const void *ip6hdr);
247
248
249 static struct tcp_function_block tcp_def_funcblk = {
250 "default",
251 tcp_output,
252 tcp_do_segment,
253 tcp_default_ctloutput,
254 NULL,
255 NULL,
256 NULL,
257 NULL,
258 NULL,
259 NULL,
260 0,
261 0
262 };
263
264 int t_functions_inited = 0;
265 struct tcp_funchead t_functions;
266 static struct tcp_function_block *tcp_func_set_ptr = &tcp_def_funcblk;
267
268 static void
269 init_tcp_functions(void)
270 {
271 if (t_functions_inited == 0) {
272 TAILQ_INIT(&t_functions);
273 rw_init_flags(&tcp_function_lock, "tcp_func_lock" , 0);
274 t_functions_inited = 1;
275 }
276 }
277
278 static struct tcp_function_block *
279 find_tcp_functions_locked(struct tcp_function_set *fs)
280 {
281 struct tcp_function *f;
282 struct tcp_function_block *blk=NULL;
283
284 TAILQ_FOREACH(f, &t_functions, tf_next) {
285 if (strcmp(f->tf_fb->tfb_tcp_block_name, fs->function_set_name) == 0) {
286 blk = f->tf_fb;
287 break;
288 }
289 }
290 return(blk);
291 }
292
293 static struct tcp_function_block *
294 find_tcp_fb_locked(struct tcp_function_block *blk, struct tcp_function **s)
295 {
296 struct tcp_function_block *rblk=NULL;
297 struct tcp_function *f;
298
299 TAILQ_FOREACH(f, &t_functions, tf_next) {
300 if (f->tf_fb == blk) {
301 rblk = blk;
302 if (s) {
303 *s = f;
304 }
305 break;
306 }
307 }
308 return (rblk);
309 }
310
311 struct tcp_function_block *
312 find_and_ref_tcp_functions(struct tcp_function_set *fs)
313 {
314 struct tcp_function_block *blk;
315
316 rw_rlock(&tcp_function_lock);
317 blk = find_tcp_functions_locked(fs);
318 if (blk)
319 refcount_acquire(&blk->tfb_refcnt);
320 rw_runlock(&tcp_function_lock);
321 return(blk);
322 }
323
324 struct tcp_function_block *
325 find_and_ref_tcp_fb(struct tcp_function_block *blk)
326 {
327 struct tcp_function_block *rblk;
328
329 rw_rlock(&tcp_function_lock);
330 rblk = find_tcp_fb_locked(blk, NULL);
331 if (rblk)
332 refcount_acquire(&rblk->tfb_refcnt);
333 rw_runlock(&tcp_function_lock);
334 return(rblk);
335 }
336
337
338 static int
339 sysctl_net_inet_default_tcp_functions(SYSCTL_HANDLER_ARGS)
340 {
341 int error=ENOENT;
342 struct tcp_function_set fs;
343 struct tcp_function_block *blk;
344
345 memset(&fs, 0, sizeof(fs));
346 rw_rlock(&tcp_function_lock);
347 blk = find_tcp_fb_locked(tcp_func_set_ptr, NULL);
348 if (blk) {
349 /* Found him */
350 strcpy(fs.function_set_name, blk->tfb_tcp_block_name);
351 fs.pcbcnt = blk->tfb_refcnt;
352 }
353 rw_runlock(&tcp_function_lock);
354 error = sysctl_handle_string(oidp, fs.function_set_name,
355 sizeof(fs.function_set_name), req);
356
357 /* Check for error or no change */
358 if (error != 0 || req->newptr == NULL)
359 return(error);
360
361 rw_wlock(&tcp_function_lock);
362 blk = find_tcp_functions_locked(&fs);
363 if ((blk == NULL) ||
364 (blk->tfb_flags & TCP_FUNC_BEING_REMOVED)) {
365 error = ENOENT;
366 goto done;
367 }
368 tcp_func_set_ptr = blk;
369 done:
370 rw_wunlock(&tcp_function_lock);
371 return (error);
372 }
373
374 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_default,
375 CTLTYPE_STRING | CTLFLAG_RW,
376 NULL, 0, sysctl_net_inet_default_tcp_functions, "A",
377 "Set/get the default TCP functions");
378
379 static int
380 sysctl_net_inet_list_available(SYSCTL_HANDLER_ARGS)
381 {
382 int error, cnt, linesz;
383 struct tcp_function *f;
384 char *buffer, *cp;
385 size_t bufsz, outsz;
386
387 cnt = 0;
388 rw_rlock(&tcp_function_lock);
389 TAILQ_FOREACH(f, &t_functions, tf_next) {
390 cnt++;
391 }
392 rw_runlock(&tcp_function_lock);
393
394 bufsz = (cnt+2) * (TCP_FUNCTION_NAME_LEN_MAX + 12) + 1;
395 buffer = malloc(bufsz, M_TEMP, M_WAITOK);
396
397 error = 0;
398 cp = buffer;
399
400 linesz = snprintf(cp, bufsz, "\n%-32s%c %s\n", "Stack", 'D', "PCB count");
401 cp += linesz;
402 bufsz -= linesz;
403 outsz = linesz;
404
405 rw_rlock(&tcp_function_lock);
406 TAILQ_FOREACH(f, &t_functions, tf_next) {
407 linesz = snprintf(cp, bufsz, "%-32s%c %u\n",
408 f->tf_fb->tfb_tcp_block_name,
409 (f->tf_fb == tcp_func_set_ptr) ? '*' : ' ',
410 f->tf_fb->tfb_refcnt);
411 if (linesz >= bufsz) {
412 error = EOVERFLOW;
413 break;
414 }
415 cp += linesz;
416 bufsz -= linesz;
417 outsz += linesz;
418 }
419 rw_runlock(&tcp_function_lock);
420 if (error == 0)
421 error = sysctl_handle_string(oidp, buffer, outsz + 1, req);
422 free(buffer, M_TEMP);
423 return (error);
424 }
425
426 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_available,
427 CTLTYPE_STRING|CTLFLAG_RD,
428 NULL, 0, sysctl_net_inet_list_available, "A",
429 "list available TCP Function sets");
430
431 /*
432 * Target size of TCP PCB hash tables. Must be a power of two.
433 *
434 * Note that this can be overridden by the kernel environment
435 * variable net.inet.tcp.tcbhashsize
436 */
437 #ifndef TCBHASHSIZE
438 #define TCBHASHSIZE 0
439 #endif
440
441 /*
442 * XXX
443 * Callouts should be moved into struct tcp directly. They are currently
444 * separate because the tcpcb structure is exported to userland for sysctl
445 * parsing purposes, which do not know about callouts.
446 */
447 struct tcpcb_mem {
448 struct tcpcb tcb;
449 struct tcp_timer tt;
450 struct cc_var ccv;
451 struct osd osd;
452 };
453
454 static VNET_DEFINE(uma_zone_t, tcpcb_zone);
455 #define V_tcpcb_zone VNET(tcpcb_zone)
456
457 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
458 MALLOC_DEFINE(M_TCPFUNCTIONS, "tcpfunc", "TCP function set memory");
459
460 static struct mtx isn_mtx;
461
462 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF)
463 #define ISN_LOCK() mtx_lock(&isn_mtx)
464 #define ISN_UNLOCK() mtx_unlock(&isn_mtx)
465
466 /*
467 * TCP initialization.
468 */
469 static void
470 tcp_zone_change(void *tag)
471 {
472
473 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets);
474 uma_zone_set_max(V_tcpcb_zone, maxsockets);
475 tcp_tw_zone_change();
476 }
477
478 static int
479 tcp_inpcb_init(void *mem, int size, int flags)
480 {
481 struct inpcb *inp = mem;
482
483 INP_LOCK_INIT(inp, "inp", "tcpinp");
484 return (0);
485 }
486
487 /*
488 * Take a value and get the next power of 2 that doesn't overflow.
489 * Used to size the tcp_inpcb hash buckets.
490 */
491 static int
492 maketcp_hashsize(int size)
493 {
494 int hashsize;
495
496 /*
497 * auto tune.
498 * get the next power of 2 higher than maxsockets.
499 */
500 hashsize = 1 << fls(size);
501 /* catch overflow, and just go one power of 2 smaller */
502 if (hashsize < size) {
503 hashsize = 1 << (fls(size) - 1);
504 }
505 return (hashsize);
506 }
507
508 int
509 register_tcp_functions(struct tcp_function_block *blk, int wait)
510 {
511 struct tcp_function_block *lblk;
512 struct tcp_function *n;
513 struct tcp_function_set fs;
514
515 if (t_functions_inited == 0) {
516 init_tcp_functions();
517 }
518 if ((blk->tfb_tcp_output == NULL) ||
519 (blk->tfb_tcp_do_segment == NULL) ||
520 (blk->tfb_tcp_ctloutput == NULL) ||
521 (strlen(blk->tfb_tcp_block_name) == 0)) {
522 /*
523 * These functions are required and you
524 * need a name.
525 */
526 return (EINVAL);
527 }
528 if (blk->tfb_tcp_timer_stop_all ||
529 blk->tfb_tcp_timer_activate ||
530 blk->tfb_tcp_timer_active ||
531 blk->tfb_tcp_timer_stop) {
532 /*
533 * If you define one timer function you
534 * must have them all.
535 */
536 if ((blk->tfb_tcp_timer_stop_all == NULL) ||
537 (blk->tfb_tcp_timer_activate == NULL) ||
538 (blk->tfb_tcp_timer_active == NULL) ||
539 (blk->tfb_tcp_timer_stop == NULL)) {
540 return (EINVAL);
541 }
542 }
543 n = malloc(sizeof(struct tcp_function), M_TCPFUNCTIONS, wait);
544 if (n == NULL) {
545 return (ENOMEM);
546 }
547 n->tf_fb = blk;
548 strcpy(fs.function_set_name, blk->tfb_tcp_block_name);
549 rw_wlock(&tcp_function_lock);
550 lblk = find_tcp_functions_locked(&fs);
551 if (lblk) {
552 /* Duplicate name space not allowed */
553 rw_wunlock(&tcp_function_lock);
554 free(n, M_TCPFUNCTIONS);
555 return (EALREADY);
556 }
557 refcount_init(&blk->tfb_refcnt, 0);
558 blk->tfb_flags = 0;
559 TAILQ_INSERT_TAIL(&t_functions, n, tf_next);
560 rw_wunlock(&tcp_function_lock);
561 return(0);
562 }
563
564 int
565 deregister_tcp_functions(struct tcp_function_block *blk)
566 {
567 struct tcp_function_block *lblk;
568 struct tcp_function *f;
569 int error=ENOENT;
570
571 if (strcmp(blk->tfb_tcp_block_name, "default") == 0) {
572 /* You can't un-register the default */
573 return (EPERM);
574 }
575 rw_wlock(&tcp_function_lock);
576 if (blk == tcp_func_set_ptr) {
577 /* You can't free the current default */
578 rw_wunlock(&tcp_function_lock);
579 return (EBUSY);
580 }
581 if (blk->tfb_refcnt) {
582 /* Still tcb attached, mark it. */
583 blk->tfb_flags |= TCP_FUNC_BEING_REMOVED;
584 rw_wunlock(&tcp_function_lock);
585 return (EBUSY);
586 }
587 lblk = find_tcp_fb_locked(blk, &f);
588 if (lblk) {
589 /* Found */
590 TAILQ_REMOVE(&t_functions, f, tf_next);
591 f->tf_fb = NULL;
592 free(f, M_TCPFUNCTIONS);
593 error = 0;
594 }
595 rw_wunlock(&tcp_function_lock);
596 return (error);
597 }
598
599 void
600 tcp_init(void)
601 {
602 const char *tcbhash_tuneable;
603 int hashsize;
604
605 tcbhash_tuneable = "net.inet.tcp.tcbhashsize";
606
607 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN,
608 &V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
609 printf("%s: WARNING: unable to register helper hook\n", __func__);
610 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT,
611 &V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
612 printf("%s: WARNING: unable to register helper hook\n", __func__);
613 hashsize = TCBHASHSIZE;
614 TUNABLE_INT_FETCH(tcbhash_tuneable, &hashsize);
615 if (hashsize == 0) {
616 /*
617 * Auto tune the hash size based on maxsockets.
618 * A perfect hash would have a 1:1 mapping
619 * (hashsize = maxsockets) however it's been
620 * suggested that O(2) average is better.
621 */
622 hashsize = maketcp_hashsize(maxsockets / 4);
623 /*
624 * Our historical default is 512,
625 * do not autotune lower than this.
626 */
627 if (hashsize < 512)
628 hashsize = 512;
629 if (bootverbose && IS_DEFAULT_VNET(curvnet))
630 printf("%s: %s auto tuned to %d\n", __func__,
631 tcbhash_tuneable, hashsize);
632 }
633 /*
634 * We require a hashsize to be a power of two.
635 * Previously if it was not a power of two we would just reset it
636 * back to 512, which could be a nasty surprise if you did not notice
637 * the error message.
638 * Instead what we do is clip it to the closest power of two lower
639 * than the specified hash value.
640 */
641 if (!powerof2(hashsize)) {
642 int oldhashsize = hashsize;
643
644 hashsize = maketcp_hashsize(hashsize);
645 /* prevent absurdly low value */
646 if (hashsize < 16)
647 hashsize = 16;
648 printf("%s: WARNING: TCB hash size not a power of 2, "
649 "clipped from %d to %d.\n", __func__, oldhashsize,
650 hashsize);
651 }
652 in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize,
653 "tcp_inpcb", tcp_inpcb_init, NULL, 0, IPI_HASHFIELDS_4TUPLE);
654
655 /*
656 * These have to be type stable for the benefit of the timers.
657 */
658 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
659 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
660 uma_zone_set_max(V_tcpcb_zone, maxsockets);
661 uma_zone_set_warning(V_tcpcb_zone, "kern.ipc.maxsockets limit reached");
662
663 tcp_tw_init();
664 syncache_init();
665 tcp_hc_init();
666
667 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
668 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
669 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
670
671 /* Skip initialization of globals for non-default instances. */
672 if (!IS_DEFAULT_VNET(curvnet))
673 return;
674
675 tcp_reass_global_init();
676
677 /* XXX virtualize those bellow? */
678 tcp_delacktime = TCPTV_DELACK;
679 tcp_keepinit = TCPTV_KEEP_INIT;
680 tcp_keepidle = TCPTV_KEEP_IDLE;
681 tcp_keepintvl = TCPTV_KEEPINTVL;
682 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
683 tcp_msl = TCPTV_MSL;
684 tcp_rexmit_min = TCPTV_MIN;
685 if (tcp_rexmit_min < 1)
686 tcp_rexmit_min = 1;
687 tcp_persmin = TCPTV_PERSMIN;
688 tcp_persmax = TCPTV_PERSMAX;
689 tcp_rexmit_slop = TCPTV_CPU_VAR;
690 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
691 tcp_tcbhashsize = hashsize;
692 /* Setup the tcp function block list */
693 init_tcp_functions();
694 register_tcp_functions(&tcp_def_funcblk, M_WAITOK);
695
696 if (tcp_soreceive_stream) {
697 #ifdef INET
698 tcp_usrreqs.pru_soreceive = soreceive_stream;
699 #endif
700 #ifdef INET6
701 tcp6_usrreqs.pru_soreceive = soreceive_stream;
702 #endif /* INET6 */
703 }
704
705 #ifdef INET6
706 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
707 #else /* INET6 */
708 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
709 #endif /* INET6 */
710 if (max_protohdr < TCP_MINPROTOHDR)
711 max_protohdr = TCP_MINPROTOHDR;
712 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
713 panic("tcp_init");
714 #undef TCP_MINPROTOHDR
715
716 ISN_LOCK_INIT();
717 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
718 SHUTDOWN_PRI_DEFAULT);
719 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL,
720 EVENTHANDLER_PRI_ANY);
721 #ifdef TCPPCAP
722 tcp_pcap_init();
723 #endif
724
725 #ifdef TCP_RFC7413
726 tcp_fastopen_init();
727 #endif
728 }
729
730 #ifdef VIMAGE
731 static void
732 tcp_destroy(void *unused __unused)
733 {
734 int error, n;
735
736 /*
737 * All our processes are gone, all our sockets should be cleaned
738 * up, which means, we should be past the tcp_discardcb() calls.
739 * Sleep to let all tcpcb timers really disappear and cleanup.
740 */
741 for (;;) {
742 INP_LIST_RLOCK(&V_tcbinfo);
743 n = V_tcbinfo.ipi_count;
744 INP_LIST_RUNLOCK(&V_tcbinfo);
745 if (n == 0)
746 break;
747 pause("tcpdes", hz / 10);
748 }
749 tcp_hc_destroy();
750 syncache_destroy();
751 tcp_tw_destroy();
752 in_pcbinfo_destroy(&V_tcbinfo);
753 /* tcp_discardcb() clears the sack_holes up. */
754 uma_zdestroy(V_sack_hole_zone);
755 uma_zdestroy(V_tcpcb_zone);
756
757 #ifdef TCP_RFC7413
758 /*
759 * Cannot free the zone until all tcpcbs are released as we attach
760 * the allocations to them.
761 */
762 tcp_fastopen_destroy();
763 #endif
764
765 error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_IN]);
766 if (error != 0) {
767 printf("%s: WARNING: unable to deregister helper hook "
768 "type=%d, id=%d: error %d returned\n", __func__,
769 HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN, error);
770 }
771 error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_OUT]);
772 if (error != 0) {
773 printf("%s: WARNING: unable to deregister helper hook "
774 "type=%d, id=%d: error %d returned\n", __func__,
775 HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT, error);
776 }
777 }
778 VNET_SYSUNINIT(tcp, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH, tcp_destroy, NULL);
779 #endif
780
781 void
782 tcp_fini(void *xtp)
783 {
784
785 }
786
787 /*
788 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
789 * tcp_template used to store this data in mbufs, but we now recopy it out
790 * of the tcpcb each time to conserve mbufs.
791 */
792 void
793 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr)
794 {
795 struct tcphdr *th = (struct tcphdr *)tcp_ptr;
796
797 INP_WLOCK_ASSERT(inp);
798
799 #ifdef INET6
800 if ((inp->inp_vflag & INP_IPV6) != 0) {
801 struct ip6_hdr *ip6;
802
803 ip6 = (struct ip6_hdr *)ip_ptr;
804 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
805 (inp->inp_flow & IPV6_FLOWINFO_MASK);
806 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
807 (IPV6_VERSION & IPV6_VERSION_MASK);
808 ip6->ip6_nxt = IPPROTO_TCP;
809 ip6->ip6_plen = htons(sizeof(struct tcphdr));
810 ip6->ip6_src = inp->in6p_laddr;
811 ip6->ip6_dst = inp->in6p_faddr;
812 }
813 #endif /* INET6 */
814 #if defined(INET6) && defined(INET)
815 else
816 #endif
817 #ifdef INET
818 {
819 struct ip *ip;
820
821 ip = (struct ip *)ip_ptr;
822 ip->ip_v = IPVERSION;
823 ip->ip_hl = 5;
824 ip->ip_tos = inp->inp_ip_tos;
825 ip->ip_len = 0;
826 ip->ip_id = 0;
827 ip->ip_off = 0;
828 ip->ip_ttl = inp->inp_ip_ttl;
829 ip->ip_sum = 0;
830 ip->ip_p = IPPROTO_TCP;
831 ip->ip_src = inp->inp_laddr;
832 ip->ip_dst = inp->inp_faddr;
833 }
834 #endif /* INET */
835 th->th_sport = inp->inp_lport;
836 th->th_dport = inp->inp_fport;
837 th->th_seq = 0;
838 th->th_ack = 0;
839 th->th_x2 = 0;
840 th->th_off = 5;
841 th->th_flags = 0;
842 th->th_win = 0;
843 th->th_urp = 0;
844 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */
845 }
846
847 /*
848 * Create template to be used to send tcp packets on a connection.
849 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
850 * use for this function is in keepalives, which use tcp_respond.
851 */
852 struct tcptemp *
853 tcpip_maketemplate(struct inpcb *inp)
854 {
855 struct tcptemp *t;
856
857 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT);
858 if (t == NULL)
859 return (NULL);
860 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t);
861 return (t);
862 }
863
864 /*
865 * Send a single message to the TCP at address specified by
866 * the given TCP/IP header. If m == NULL, then we make a copy
867 * of the tcpiphdr at th and send directly to the addressed host.
868 * This is used to force keep alive messages out using the TCP
869 * template for a connection. If flags are given then we send
870 * a message back to the TCP which originated the segment th,
871 * and discard the mbuf containing it and any other attached mbufs.
872 *
873 * In any case the ack and sequence number of the transmitted
874 * segment are as specified by the parameters.
875 *
876 * NOTE: If m != NULL, then th must point to *inside* the mbuf.
877 */
878 void
879 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
880 tcp_seq ack, tcp_seq seq, int flags)
881 {
882 struct tcpopt to;
883 struct inpcb *inp;
884 struct ip *ip;
885 struct mbuf *optm;
886 struct tcphdr *nth;
887 u_char *optp;
888 #ifdef INET6
889 struct ip6_hdr *ip6;
890 int isipv6;
891 #endif /* INET6 */
892 int optlen, tlen, win;
893 bool incl_opts;
894
895 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
896
897 #ifdef INET6
898 isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4);
899 ip6 = ipgen;
900 #endif /* INET6 */
901 ip = ipgen;
902
903 if (tp != NULL) {
904 inp = tp->t_inpcb;
905 KASSERT(inp != NULL, ("tcp control block w/o inpcb"));
906 INP_WLOCK_ASSERT(inp);
907 } else
908 inp = NULL;
909
910 incl_opts = false;
911 win = 0;
912 if (tp != NULL) {
913 if (!(flags & TH_RST)) {
914 win = sbspace(&inp->inp_socket->so_rcv);
915 if (win > (long)TCP_MAXWIN << tp->rcv_scale)
916 win = (long)TCP_MAXWIN << tp->rcv_scale;
917 }
918 if ((tp->t_flags & TF_NOOPT) == 0)
919 incl_opts = true;
920 }
921 if (m == NULL) {
922 m = m_gethdr(M_NOWAIT, MT_DATA);
923 if (m == NULL)
924 return;
925 m->m_data += max_linkhdr;
926 #ifdef INET6
927 if (isipv6) {
928 bcopy((caddr_t)ip6, mtod(m, caddr_t),
929 sizeof(struct ip6_hdr));
930 ip6 = mtod(m, struct ip6_hdr *);
931 nth = (struct tcphdr *)(ip6 + 1);
932 } else
933 #endif /* INET6 */
934 {
935 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
936 ip = mtod(m, struct ip *);
937 nth = (struct tcphdr *)(ip + 1);
938 }
939 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
940 flags = TH_ACK;
941 } else if (!M_WRITABLE(m)) {
942 struct mbuf *n;
943
944 /* Can't reuse 'm', allocate a new mbuf. */
945 n = m_gethdr(M_NOWAIT, MT_DATA);
946 if (n == NULL) {
947 m_freem(m);
948 return;
949 }
950
951 if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
952 m_freem(m);
953 m_freem(n);
954 return;
955 }
956
957 n->m_data += max_linkhdr;
958 /* m_len is set later */
959 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
960 #ifdef INET6
961 if (isipv6) {
962 bcopy((caddr_t)ip6, mtod(n, caddr_t),
963 sizeof(struct ip6_hdr));
964 ip6 = mtod(n, struct ip6_hdr *);
965 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
966 nth = (struct tcphdr *)(ip6 + 1);
967 } else
968 #endif /* INET6 */
969 {
970 bcopy((caddr_t)ip, mtod(n, caddr_t), sizeof(struct ip));
971 ip = mtod(n, struct ip *);
972 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
973 nth = (struct tcphdr *)(ip + 1);
974 }
975 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
976 xchg(nth->th_dport, nth->th_sport, uint16_t);
977 th = nth;
978 m_freem(m);
979 m = n;
980 } else {
981 /*
982 * reuse the mbuf.
983 * XXX MRT We inherit the FIB, which is lucky.
984 */
985 m_freem(m->m_next);
986 m->m_next = NULL;
987 m->m_data = (caddr_t)ipgen;
988 /* m_len is set later */
989 #ifdef INET6
990 if (isipv6) {
991 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
992 nth = (struct tcphdr *)(ip6 + 1);
993 } else
994 #endif /* INET6 */
995 {
996 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
997 nth = (struct tcphdr *)(ip + 1);
998 }
999 if (th != nth) {
1000 /*
1001 * this is usually a case when an extension header
1002 * exists between the IPv6 header and the
1003 * TCP header.
1004 */
1005 nth->th_sport = th->th_sport;
1006 nth->th_dport = th->th_dport;
1007 }
1008 xchg(nth->th_dport, nth->th_sport, uint16_t);
1009 #undef xchg
1010 }
1011 tlen = 0;
1012 #ifdef INET6
1013 if (isipv6)
1014 tlen = sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
1015 #endif
1016 #if defined(INET) && defined(INET6)
1017 else
1018 #endif
1019 #ifdef INET
1020 tlen = sizeof (struct tcpiphdr);
1021 #endif
1022 #ifdef INVARIANTS
1023 m->m_len = 0;
1024 KASSERT(M_TRAILINGSPACE(m) >= tlen,
1025 ("Not enough trailing space for message (m=%p, need=%d, have=%ld)",
1026 m, tlen, (long)M_TRAILINGSPACE(m)));
1027 #endif
1028 m->m_len = tlen;
1029 to.to_flags = 0;
1030 if (incl_opts) {
1031 /* Make sure we have room. */
1032 if (M_TRAILINGSPACE(m) < TCP_MAXOLEN) {
1033 m->m_next = m_get(M_NOWAIT, MT_DATA);
1034 if (m->m_next) {
1035 optp = mtod(m->m_next, u_char *);
1036 optm = m->m_next;
1037 } else
1038 incl_opts = false;
1039 } else {
1040 optp = (u_char *) (nth + 1);
1041 optm = m;
1042 }
1043 }
1044 if (incl_opts) {
1045 /* Timestamps. */
1046 if (tp->t_flags & TF_RCVD_TSTMP) {
1047 to.to_tsval = tcp_ts_getticks() + tp->ts_offset;
1048 to.to_tsecr = tp->ts_recent;
1049 to.to_flags |= TOF_TS;
1050 }
1051 #ifdef TCP_SIGNATURE
1052 /* TCP-MD5 (RFC2385). */
1053 if (tp->t_flags & TF_SIGNATURE)
1054 to.to_flags |= TOF_SIGNATURE;
1055 #endif
1056
1057 /* Add the options. */
1058 tlen += optlen = tcp_addoptions(&to, optp);
1059
1060 /* Update m_len in the correct mbuf. */
1061 optm->m_len += optlen;
1062 } else
1063 optlen = 0;
1064 #ifdef INET6
1065 if (isipv6) {
1066 ip6->ip6_flow = 0;
1067 ip6->ip6_vfc = IPV6_VERSION;
1068 ip6->ip6_nxt = IPPROTO_TCP;
1069 ip6->ip6_plen = htons(tlen - sizeof(*ip6));
1070 }
1071 #endif
1072 #if defined(INET) && defined(INET6)
1073 else
1074 #endif
1075 #ifdef INET
1076 {
1077 ip->ip_len = htons(tlen);
1078 ip->ip_ttl = V_ip_defttl;
1079 if (V_path_mtu_discovery)
1080 ip->ip_off |= htons(IP_DF);
1081 }
1082 #endif
1083 m->m_pkthdr.len = tlen;
1084 m->m_pkthdr.rcvif = NULL;
1085 #ifdef MAC
1086 if (inp != NULL) {
1087 /*
1088 * Packet is associated with a socket, so allow the
1089 * label of the response to reflect the socket label.
1090 */
1091 INP_WLOCK_ASSERT(inp);
1092 mac_inpcb_create_mbuf(inp, m);
1093 } else {
1094 /*
1095 * Packet is not associated with a socket, so possibly
1096 * update the label in place.
1097 */
1098 mac_netinet_tcp_reply(m);
1099 }
1100 #endif
1101 nth->th_seq = htonl(seq);
1102 nth->th_ack = htonl(ack);
1103 nth->th_x2 = 0;
1104 nth->th_off = (sizeof (struct tcphdr) + optlen) >> 2;
1105 nth->th_flags = flags;
1106 if (tp != NULL)
1107 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
1108 else
1109 nth->th_win = htons((u_short)win);
1110 nth->th_urp = 0;
1111
1112 #ifdef TCP_SIGNATURE
1113 if (to.to_flags & TOF_SIGNATURE) {
1114 tcp_signature_compute(m, 0, 0, optlen, to.to_signature,
1115 IPSEC_DIR_OUTBOUND);
1116 }
1117 #endif
1118
1119 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
1120 #ifdef INET6
1121 if (isipv6) {
1122 m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
1123 nth->th_sum = in6_cksum_pseudo(ip6,
1124 tlen - sizeof(struct ip6_hdr), IPPROTO_TCP, 0);
1125 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb :
1126 NULL, NULL);
1127 }
1128 #endif /* INET6 */
1129 #if defined(INET6) && defined(INET)
1130 else
1131 #endif
1132 #ifdef INET
1133 {
1134 m->m_pkthdr.csum_flags = CSUM_TCP;
1135 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
1136 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
1137 }
1138 #endif /* INET */
1139 #ifdef TCPDEBUG
1140 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
1141 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
1142 #endif
1143 TCP_PROBE3(debug__output, tp, th, mtod(m, const char *));
1144 if (flags & TH_RST)
1145 TCP_PROBE5(accept__refused, NULL, NULL, mtod(m, const char *),
1146 tp, nth);
1147
1148 TCP_PROBE5(send, NULL, tp, mtod(m, const char *), tp, nth);
1149 #ifdef INET6
1150 if (isipv6)
1151 (void) ip6_output(m, NULL, NULL, 0, NULL, NULL, inp);
1152 #endif /* INET6 */
1153 #if defined(INET) && defined(INET6)
1154 else
1155 #endif
1156 #ifdef INET
1157 (void) ip_output(m, NULL, NULL, 0, NULL, inp);
1158 #endif
1159 }
1160
1161 /*
1162 * Create a new TCP control block, making an
1163 * empty reassembly queue and hooking it to the argument
1164 * protocol control block. The `inp' parameter must have
1165 * come from the zone allocator set up in tcp_init().
1166 */
1167 struct tcpcb *
1168 tcp_newtcpcb(struct inpcb *inp)
1169 {
1170 struct tcpcb_mem *tm;
1171 struct tcpcb *tp;
1172 #ifdef INET6
1173 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
1174 #endif /* INET6 */
1175
1176 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO);
1177 if (tm == NULL)
1178 return (NULL);
1179 tp = &tm->tcb;
1180
1181 /* Initialise cc_var struct for this tcpcb. */
1182 tp->ccv = &tm->ccv;
1183 tp->ccv->type = IPPROTO_TCP;
1184 tp->ccv->ccvc.tcp = tp;
1185 rw_rlock(&tcp_function_lock);
1186 tp->t_fb = tcp_func_set_ptr;
1187 refcount_acquire(&tp->t_fb->tfb_refcnt);
1188 rw_runlock(&tcp_function_lock);
1189 if (tp->t_fb->tfb_tcp_fb_init) {
1190 (*tp->t_fb->tfb_tcp_fb_init)(tp);
1191 }
1192 /*
1193 * Use the current system default CC algorithm.
1194 */
1195 CC_LIST_RLOCK();
1196 KASSERT(!STAILQ_EMPTY(&cc_list), ("cc_list is empty!"));
1197 CC_ALGO(tp) = CC_DEFAULT();
1198 CC_LIST_RUNLOCK();
1199
1200 if (CC_ALGO(tp)->cb_init != NULL)
1201 if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) {
1202 if (tp->t_fb->tfb_tcp_fb_fini)
1203 (*tp->t_fb->tfb_tcp_fb_fini)(tp);
1204 refcount_release(&tp->t_fb->tfb_refcnt);
1205 uma_zfree(V_tcpcb_zone, tm);
1206 return (NULL);
1207 }
1208
1209 tp->osd = &tm->osd;
1210 if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) {
1211 if (tp->t_fb->tfb_tcp_fb_fini)
1212 (*tp->t_fb->tfb_tcp_fb_fini)(tp);
1213 refcount_release(&tp->t_fb->tfb_refcnt);
1214 uma_zfree(V_tcpcb_zone, tm);
1215 return (NULL);
1216 }
1217
1218 #ifdef VIMAGE
1219 tp->t_vnet = inp->inp_vnet;
1220 #endif
1221 tp->t_timers = &tm->tt;
1222 /* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */
1223 tp->t_maxseg =
1224 #ifdef INET6
1225 isipv6 ? V_tcp_v6mssdflt :
1226 #endif /* INET6 */
1227 V_tcp_mssdflt;
1228
1229 /* Set up our timeouts. */
1230 callout_init(&tp->t_timers->tt_rexmt, 1);
1231 callout_init(&tp->t_timers->tt_persist, 1);
1232 callout_init(&tp->t_timers->tt_keep, 1);
1233 callout_init(&tp->t_timers->tt_2msl, 1);
1234 callout_init(&tp->t_timers->tt_delack, 1);
1235
1236 if (V_tcp_do_rfc1323)
1237 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
1238 if (V_tcp_do_sack)
1239 tp->t_flags |= TF_SACK_PERMIT;
1240 TAILQ_INIT(&tp->snd_holes);
1241 /*
1242 * The tcpcb will hold a reference on its inpcb until tcp_discardcb()
1243 * is called.
1244 */
1245 in_pcbref(inp); /* Reference for tcpcb */
1246 tp->t_inpcb = inp;
1247
1248 /*
1249 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
1250 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
1251 * reasonable initial retransmit time.
1252 */
1253 tp->t_srtt = TCPTV_SRTTBASE;
1254 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
1255 tp->t_rttmin = tcp_rexmit_min;
1256 tp->t_rxtcur = TCPTV_RTOBASE;
1257 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1258 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1259 tp->t_rcvtime = ticks;
1260 /*
1261 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
1262 * because the socket may be bound to an IPv6 wildcard address,
1263 * which may match an IPv4-mapped IPv6 address.
1264 */
1265 inp->inp_ip_ttl = V_ip_defttl;
1266 inp->inp_ppcb = tp;
1267 #ifdef TCPPCAP
1268 /*
1269 * Init the TCP PCAP queues.
1270 */
1271 tcp_pcap_tcpcb_init(tp);
1272 #endif
1273 return (tp); /* XXX */
1274 }
1275
1276 /*
1277 * Switch the congestion control algorithm back to NewReno for any active
1278 * control blocks using an algorithm which is about to go away.
1279 * This ensures the CC framework can allow the unload to proceed without leaving
1280 * any dangling pointers which would trigger a panic.
1281 * Returning non-zero would inform the CC framework that something went wrong
1282 * and it would be unsafe to allow the unload to proceed. However, there is no
1283 * way for this to occur with this implementation so we always return zero.
1284 */
1285 int
1286 tcp_ccalgounload(struct cc_algo *unload_algo)
1287 {
1288 struct cc_algo *tmpalgo;
1289 struct inpcb *inp;
1290 struct tcpcb *tp;
1291 VNET_ITERATOR_DECL(vnet_iter);
1292
1293 /*
1294 * Check all active control blocks across all network stacks and change
1295 * any that are using "unload_algo" back to NewReno. If "unload_algo"
1296 * requires cleanup code to be run, call it.
1297 */
1298 VNET_LIST_RLOCK();
1299 VNET_FOREACH(vnet_iter) {
1300 CURVNET_SET(vnet_iter);
1301 INP_INFO_WLOCK(&V_tcbinfo);
1302 /*
1303 * New connections already part way through being initialised
1304 * with the CC algo we're removing will not race with this code
1305 * because the INP_INFO_WLOCK is held during initialisation. We
1306 * therefore don't enter the loop below until the connection
1307 * list has stabilised.
1308 */
1309 LIST_FOREACH(inp, &V_tcb, inp_list) {
1310 INP_WLOCK(inp);
1311 /* Important to skip tcptw structs. */
1312 if (!(inp->inp_flags & INP_TIMEWAIT) &&
1313 (tp = intotcpcb(inp)) != NULL) {
1314 /*
1315 * By holding INP_WLOCK here, we are assured
1316 * that the connection is not currently
1317 * executing inside the CC module's functions
1318 * i.e. it is safe to make the switch back to
1319 * NewReno.
1320 */
1321 if (CC_ALGO(tp) == unload_algo) {
1322 tmpalgo = CC_ALGO(tp);
1323 /* NewReno does not require any init. */
1324 CC_ALGO(tp) = &newreno_cc_algo;
1325 if (tmpalgo->cb_destroy != NULL)
1326 tmpalgo->cb_destroy(tp->ccv);
1327 }
1328 }
1329 INP_WUNLOCK(inp);
1330 }
1331 INP_INFO_WUNLOCK(&V_tcbinfo);
1332 CURVNET_RESTORE();
1333 }
1334 VNET_LIST_RUNLOCK();
1335
1336 return (0);
1337 }
1338
1339 /*
1340 * Drop a TCP connection, reporting
1341 * the specified error. If connection is synchronized,
1342 * then send a RST to peer.
1343 */
1344 struct tcpcb *
1345 tcp_drop(struct tcpcb *tp, int errno)
1346 {
1347 struct socket *so = tp->t_inpcb->inp_socket;
1348
1349 INP_INFO_LOCK_ASSERT(&V_tcbinfo);
1350 INP_WLOCK_ASSERT(tp->t_inpcb);
1351
1352 if (TCPS_HAVERCVDSYN(tp->t_state)) {
1353 tcp_state_change(tp, TCPS_CLOSED);
1354 (void) tp->t_fb->tfb_tcp_output(tp);
1355 TCPSTAT_INC(tcps_drops);
1356 } else
1357 TCPSTAT_INC(tcps_conndrops);
1358 if (errno == ETIMEDOUT && tp->t_softerror)
1359 errno = tp->t_softerror;
1360 so->so_error = errno;
1361 return (tcp_close(tp));
1362 }
1363
1364 void
1365 tcp_discardcb(struct tcpcb *tp)
1366 {
1367 struct inpcb *inp = tp->t_inpcb;
1368 struct socket *so = inp->inp_socket;
1369 #ifdef INET6
1370 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
1371 #endif /* INET6 */
1372 int released;
1373
1374 INP_WLOCK_ASSERT(inp);
1375
1376 /*
1377 * Make sure that all of our timers are stopped before we delete the
1378 * PCB.
1379 *
1380 * If stopping a timer fails, we schedule a discard function in same
1381 * callout, and the last discard function called will take care of
1382 * deleting the tcpcb.
1383 */
1384 tp->t_timers->tt_draincnt = 0;
1385 tcp_timer_stop(tp, TT_REXMT);
1386 tcp_timer_stop(tp, TT_PERSIST);
1387 tcp_timer_stop(tp, TT_KEEP);
1388 tcp_timer_stop(tp, TT_2MSL);
1389 tcp_timer_stop(tp, TT_DELACK);
1390 if (tp->t_fb->tfb_tcp_timer_stop_all) {
1391 /*
1392 * Call the stop-all function of the methods,
1393 * this function should call the tcp_timer_stop()
1394 * method with each of the function specific timeouts.
1395 * That stop will be called via the tfb_tcp_timer_stop()
1396 * which should use the async drain function of the
1397 * callout system (see tcp_var.h).
1398 */
1399 tp->t_fb->tfb_tcp_timer_stop_all(tp);
1400 }
1401
1402 /*
1403 * If we got enough samples through the srtt filter,
1404 * save the rtt and rttvar in the routing entry.
1405 * 'Enough' is arbitrarily defined as 4 rtt samples.
1406 * 4 samples is enough for the srtt filter to converge
1407 * to within enough % of the correct value; fewer samples
1408 * and we could save a bogus rtt. The danger is not high
1409 * as tcp quickly recovers from everything.
1410 * XXX: Works very well but needs some more statistics!
1411 */
1412 if (tp->t_rttupdated >= 4) {
1413 struct hc_metrics_lite metrics;
1414 u_long ssthresh;
1415
1416 bzero(&metrics, sizeof(metrics));
1417 /*
1418 * Update the ssthresh always when the conditions below
1419 * are satisfied. This gives us better new start value
1420 * for the congestion avoidance for new connections.
1421 * ssthresh is only set if packet loss occurred on a session.
1422 *
1423 * XXXRW: 'so' may be NULL here, and/or socket buffer may be
1424 * being torn down. Ideally this code would not use 'so'.
1425 */
1426 ssthresh = tp->snd_ssthresh;
1427 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) {
1428 /*
1429 * convert the limit from user data bytes to
1430 * packets then to packet data bytes.
1431 */
1432 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg;
1433 if (ssthresh < 2)
1434 ssthresh = 2;
1435 ssthresh *= (u_long)(tp->t_maxseg +
1436 #ifdef INET6
1437 (isipv6 ? sizeof (struct ip6_hdr) +
1438 sizeof (struct tcphdr) :
1439 #endif
1440 sizeof (struct tcpiphdr)
1441 #ifdef INET6
1442 )
1443 #endif
1444 );
1445 } else
1446 ssthresh = 0;
1447 metrics.rmx_ssthresh = ssthresh;
1448
1449 metrics.rmx_rtt = tp->t_srtt;
1450 metrics.rmx_rttvar = tp->t_rttvar;
1451 metrics.rmx_cwnd = tp->snd_cwnd;
1452 metrics.rmx_sendpipe = 0;
1453 metrics.rmx_recvpipe = 0;
1454
1455 tcp_hc_update(&inp->inp_inc, &metrics);
1456 }
1457
1458 /* free the reassembly queue, if any */
1459 tcp_reass_flush(tp);
1460
1461 #ifdef TCP_OFFLOAD
1462 /* Disconnect offload device, if any. */
1463 if (tp->t_flags & TF_TOE)
1464 tcp_offload_detach(tp);
1465 #endif
1466
1467 tcp_free_sackholes(tp);
1468
1469 #ifdef TCPPCAP
1470 /* Free the TCP PCAP queues. */
1471 tcp_pcap_drain(&(tp->t_inpkts));
1472 tcp_pcap_drain(&(tp->t_outpkts));
1473 #endif
1474
1475 /* Allow the CC algorithm to clean up after itself. */
1476 if (CC_ALGO(tp)->cb_destroy != NULL)
1477 CC_ALGO(tp)->cb_destroy(tp->ccv);
1478
1479 khelp_destroy_osd(tp->osd);
1480
1481 CC_ALGO(tp) = NULL;
1482 inp->inp_ppcb = NULL;
1483 if (tp->t_timers->tt_draincnt == 0) {
1484 /* We own the last reference on tcpcb, let's free it. */
1485 if (tp->t_fb->tfb_tcp_fb_fini)
1486 (*tp->t_fb->tfb_tcp_fb_fini)(tp);
1487 refcount_release(&tp->t_fb->tfb_refcnt);
1488 tp->t_inpcb = NULL;
1489 uma_zfree(V_tcpcb_zone, tp);
1490 released = in_pcbrele_wlocked(inp);
1491 KASSERT(!released, ("%s: inp %p should not have been released "
1492 "here", __func__, inp));
1493 }
1494 }
1495
1496 void
1497 tcp_timer_discard(void *ptp)
1498 {
1499 struct inpcb *inp;
1500 struct tcpcb *tp;
1501
1502 tp = (struct tcpcb *)ptp;
1503 CURVNET_SET(tp->t_vnet);
1504 INP_INFO_RLOCK(&V_tcbinfo);
1505 inp = tp->t_inpcb;
1506 KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL",
1507 __func__, tp));
1508 INP_WLOCK(inp);
1509 KASSERT((tp->t_timers->tt_flags & TT_STOPPED) != 0,
1510 ("%s: tcpcb has to be stopped here", __func__));
1511 tp->t_timers->tt_draincnt--;
1512 if (tp->t_timers->tt_draincnt == 0) {
1513 /* We own the last reference on this tcpcb, let's free it. */
1514 if (tp->t_fb->tfb_tcp_fb_fini)
1515 (*tp->t_fb->tfb_tcp_fb_fini)(tp);
1516 refcount_release(&tp->t_fb->tfb_refcnt);
1517 tp->t_inpcb = NULL;
1518 uma_zfree(V_tcpcb_zone, tp);
1519 if (in_pcbrele_wlocked(inp)) {
1520 INP_INFO_RUNLOCK(&V_tcbinfo);
1521 CURVNET_RESTORE();
1522 return;
1523 }
1524 }
1525 INP_WUNLOCK(inp);
1526 INP_INFO_RUNLOCK(&V_tcbinfo);
1527 CURVNET_RESTORE();
1528 }
1529
1530 /*
1531 * Attempt to close a TCP control block, marking it as dropped, and freeing
1532 * the socket if we hold the only reference.
1533 */
1534 struct tcpcb *
1535 tcp_close(struct tcpcb *tp)
1536 {
1537 struct inpcb *inp = tp->t_inpcb;
1538 struct socket *so;
1539
1540 INP_INFO_LOCK_ASSERT(&V_tcbinfo);
1541 INP_WLOCK_ASSERT(inp);
1542
1543 #ifdef TCP_OFFLOAD
1544 if (tp->t_state == TCPS_LISTEN)
1545 tcp_offload_listen_stop(tp);
1546 #endif
1547 #ifdef TCP_RFC7413
1548 /*
1549 * This releases the TFO pending counter resource for TFO listen
1550 * sockets as well as passively-created TFO sockets that transition
1551 * from SYN_RECEIVED to CLOSED.
1552 */
1553 if (tp->t_tfo_pending) {
1554 tcp_fastopen_decrement_counter(tp->t_tfo_pending);
1555 tp->t_tfo_pending = NULL;
1556 }
1557 #endif
1558 in_pcbdrop(inp);
1559 TCPSTAT_INC(tcps_closed);
1560 TCPSTATES_DEC(tp->t_state);
1561 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
1562 so = inp->inp_socket;
1563 soisdisconnected(so);
1564 if (inp->inp_flags & INP_SOCKREF) {
1565 KASSERT(so->so_state & SS_PROTOREF,
1566 ("tcp_close: !SS_PROTOREF"));
1567 inp->inp_flags &= ~INP_SOCKREF;
1568 INP_WUNLOCK(inp);
1569 ACCEPT_LOCK();
1570 SOCK_LOCK(so);
1571 so->so_state &= ~SS_PROTOREF;
1572 sofree(so);
1573 return (NULL);
1574 }
1575 return (tp);
1576 }
1577
1578 void
1579 tcp_drain(void)
1580 {
1581 VNET_ITERATOR_DECL(vnet_iter);
1582
1583 if (!do_tcpdrain)
1584 return;
1585
1586 VNET_LIST_RLOCK_NOSLEEP();
1587 VNET_FOREACH(vnet_iter) {
1588 CURVNET_SET(vnet_iter);
1589 struct inpcb *inpb;
1590 struct tcpcb *tcpb;
1591
1592 /*
1593 * Walk the tcpbs, if existing, and flush the reassembly queue,
1594 * if there is one...
1595 * XXX: The "Net/3" implementation doesn't imply that the TCP
1596 * reassembly queue should be flushed, but in a situation
1597 * where we're really low on mbufs, this is potentially
1598 * useful.
1599 */
1600 INP_INFO_WLOCK(&V_tcbinfo);
1601 LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) {
1602 if (inpb->inp_flags & INP_TIMEWAIT)
1603 continue;
1604 INP_WLOCK(inpb);
1605 if ((tcpb = intotcpcb(inpb)) != NULL) {
1606 tcp_reass_flush(tcpb);
1607 tcp_clean_sackreport(tcpb);
1608 #ifdef TCPPCAP
1609 if (tcp_pcap_aggressive_free) {
1610 /* Free the TCP PCAP queues. */
1611 tcp_pcap_drain(&(tcpb->t_inpkts));
1612 tcp_pcap_drain(&(tcpb->t_outpkts));
1613 }
1614 #endif
1615 }
1616 INP_WUNLOCK(inpb);
1617 }
1618 INP_INFO_WUNLOCK(&V_tcbinfo);
1619 CURVNET_RESTORE();
1620 }
1621 VNET_LIST_RUNLOCK_NOSLEEP();
1622 }
1623
1624 /*
1625 * Notify a tcp user of an asynchronous error;
1626 * store error as soft error, but wake up user
1627 * (for now, won't do anything until can select for soft error).
1628 *
1629 * Do not wake up user since there currently is no mechanism for
1630 * reporting soft errors (yet - a kqueue filter may be added).
1631 */
1632 static struct inpcb *
1633 tcp_notify(struct inpcb *inp, int error)
1634 {
1635 struct tcpcb *tp;
1636
1637 INP_INFO_LOCK_ASSERT(&V_tcbinfo);
1638 INP_WLOCK_ASSERT(inp);
1639
1640 if ((inp->inp_flags & INP_TIMEWAIT) ||
1641 (inp->inp_flags & INP_DROPPED))
1642 return (inp);
1643
1644 tp = intotcpcb(inp);
1645 KASSERT(tp != NULL, ("tcp_notify: tp == NULL"));
1646
1647 /*
1648 * Ignore some errors if we are hooked up.
1649 * If connection hasn't completed, has retransmitted several times,
1650 * and receives a second error, give up now. This is better
1651 * than waiting a long time to establish a connection that
1652 * can never complete.
1653 */
1654 if (tp->t_state == TCPS_ESTABLISHED &&
1655 (error == EHOSTUNREACH || error == ENETUNREACH ||
1656 error == EHOSTDOWN)) {
1657 if (inp->inp_route.ro_rt) {
1658 RTFREE(inp->inp_route.ro_rt);
1659 inp->inp_route.ro_rt = (struct rtentry *)NULL;
1660 }
1661 return (inp);
1662 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
1663 tp->t_softerror) {
1664 tp = tcp_drop(tp, error);
1665 if (tp != NULL)
1666 return (inp);
1667 else
1668 return (NULL);
1669 } else {
1670 tp->t_softerror = error;
1671 return (inp);
1672 }
1673 #if 0
1674 wakeup( &so->so_timeo);
1675 sorwakeup(so);
1676 sowwakeup(so);
1677 #endif
1678 }
1679
1680 static int
1681 tcp_pcblist(SYSCTL_HANDLER_ARGS)
1682 {
1683 int error, i, m, n, pcb_count;
1684 struct inpcb *inp, **inp_list;
1685 inp_gen_t gencnt;
1686 struct xinpgen xig;
1687
1688 /*
1689 * The process of preparing the TCB list is too time-consuming and
1690 * resource-intensive to repeat twice on every request.
1691 */
1692 if (req->oldptr == NULL) {
1693 n = V_tcbinfo.ipi_count +
1694 counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
1695 n += imax(n / 8, 10);
1696 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
1697 return (0);
1698 }
1699
1700 if (req->newptr != NULL)
1701 return (EPERM);
1702
1703 /*
1704 * OK, now we're committed to doing something.
1705 */
1706 INP_LIST_RLOCK(&V_tcbinfo);
1707 gencnt = V_tcbinfo.ipi_gencnt;
1708 n = V_tcbinfo.ipi_count;
1709 INP_LIST_RUNLOCK(&V_tcbinfo);
1710
1711 m = counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
1712
1713 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
1714 + (n + m) * sizeof(struct xtcpcb));
1715 if (error != 0)
1716 return (error);
1717
1718 xig.xig_len = sizeof xig;
1719 xig.xig_count = n + m;
1720 xig.xig_gen = gencnt;
1721 xig.xig_sogen = so_gencnt;
1722 error = SYSCTL_OUT(req, &xig, sizeof xig);
1723 if (error)
1724 return (error);
1725
1726 error = syncache_pcblist(req, m, &pcb_count);
1727 if (error)
1728 return (error);
1729
1730 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
1731
1732 INP_INFO_WLOCK(&V_tcbinfo);
1733 for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0;
1734 inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) {
1735 INP_WLOCK(inp);
1736 if (inp->inp_gencnt <= gencnt) {
1737 /*
1738 * XXX: This use of cr_cansee(), introduced with
1739 * TCP state changes, is not quite right, but for
1740 * now, better than nothing.
1741 */
1742 if (inp->inp_flags & INP_TIMEWAIT) {
1743 if (intotw(inp) != NULL)
1744 error = cr_cansee(req->td->td_ucred,
1745 intotw(inp)->tw_cred);
1746 else
1747 error = EINVAL; /* Skip this inp. */
1748 } else
1749 error = cr_canseeinpcb(req->td->td_ucred, inp);
1750 if (error == 0) {
1751 in_pcbref(inp);
1752 inp_list[i++] = inp;
1753 }
1754 }
1755 INP_WUNLOCK(inp);
1756 }
1757 INP_INFO_WUNLOCK(&V_tcbinfo);
1758 n = i;
1759
1760 error = 0;
1761 for (i = 0; i < n; i++) {
1762 inp = inp_list[i];
1763 INP_RLOCK(inp);
1764 if (inp->inp_gencnt <= gencnt) {
1765 struct xtcpcb xt;
1766 void *inp_ppcb;
1767
1768 bzero(&xt, sizeof(xt));
1769 xt.xt_len = sizeof xt;
1770 /* XXX should avoid extra copy */
1771 bcopy(inp, &xt.xt_inp, sizeof *inp);
1772 inp_ppcb = inp->inp_ppcb;
1773 if (inp_ppcb == NULL)
1774 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
1775 else if (inp->inp_flags & INP_TIMEWAIT) {
1776 bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
1777 xt.xt_tp.t_state = TCPS_TIME_WAIT;
1778 } else {
1779 bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
1780 if (xt.xt_tp.t_timers)
1781 tcp_timer_to_xtimer(&xt.xt_tp, xt.xt_tp.t_timers, &xt.xt_timer);
1782 }
1783 if (inp->inp_socket != NULL)
1784 sotoxsocket(inp->inp_socket, &xt.xt_socket);
1785 else {
1786 bzero(&xt.xt_socket, sizeof xt.xt_socket);
1787 xt.xt_socket.xso_protocol = IPPROTO_TCP;
1788 }
1789 xt.xt_inp.inp_gencnt = inp->inp_gencnt;
1790 INP_RUNLOCK(inp);
1791 error = SYSCTL_OUT(req, &xt, sizeof xt);
1792 } else
1793 INP_RUNLOCK(inp);
1794 }
1795 INP_INFO_RLOCK(&V_tcbinfo);
1796 for (i = 0; i < n; i++) {
1797 inp = inp_list[i];
1798 INP_RLOCK(inp);
1799 if (!in_pcbrele_rlocked(inp))
1800 INP_RUNLOCK(inp);
1801 }
1802 INP_INFO_RUNLOCK(&V_tcbinfo);
1803
1804 if (!error) {
1805 /*
1806 * Give the user an updated idea of our state.
1807 * If the generation differs from what we told
1808 * her before, she knows that something happened
1809 * while we were processing this request, and it
1810 * might be necessary to retry.
1811 */
1812 INP_LIST_RLOCK(&V_tcbinfo);
1813 xig.xig_gen = V_tcbinfo.ipi_gencnt;
1814 xig.xig_sogen = so_gencnt;
1815 xig.xig_count = V_tcbinfo.ipi_count + pcb_count;
1816 INP_LIST_RUNLOCK(&V_tcbinfo);
1817 error = SYSCTL_OUT(req, &xig, sizeof xig);
1818 }
1819 free(inp_list, M_TEMP);
1820 return (error);
1821 }
1822
1823 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist,
1824 CTLTYPE_OPAQUE | CTLFLAG_RD, NULL, 0,
1825 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
1826
1827 #ifdef INET
1828 static int
1829 tcp_getcred(SYSCTL_HANDLER_ARGS)
1830 {
1831 struct xucred xuc;
1832 struct sockaddr_in addrs[2];
1833 struct inpcb *inp;
1834 int error;
1835
1836 error = priv_check(req->td, PRIV_NETINET_GETCRED);
1837 if (error)
1838 return (error);
1839 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1840 if (error)
1841 return (error);
1842 inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
1843 addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL);
1844 if (inp != NULL) {
1845 if (inp->inp_socket == NULL)
1846 error = ENOENT;
1847 if (error == 0)
1848 error = cr_canseeinpcb(req->td->td_ucred, inp);
1849 if (error == 0)
1850 cru2x(inp->inp_cred, &xuc);
1851 INP_RUNLOCK(inp);
1852 } else
1853 error = ENOENT;
1854 if (error == 0)
1855 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1856 return (error);
1857 }
1858
1859 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
1860 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1861 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection");
1862 #endif /* INET */
1863
1864 #ifdef INET6
1865 static int
1866 tcp6_getcred(SYSCTL_HANDLER_ARGS)
1867 {
1868 struct xucred xuc;
1869 struct sockaddr_in6 addrs[2];
1870 struct inpcb *inp;
1871 int error;
1872 #ifdef INET
1873 int mapped = 0;
1874 #endif
1875
1876 error = priv_check(req->td, PRIV_NETINET_GETCRED);
1877 if (error)
1878 return (error);
1879 error = SYSCTL_IN(req, addrs, sizeof(addrs));
1880 if (error)
1881 return (error);
1882 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
1883 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
1884 return (error);
1885 }
1886 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
1887 #ifdef INET
1888 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
1889 mapped = 1;
1890 else
1891 #endif
1892 return (EINVAL);
1893 }
1894
1895 #ifdef INET
1896 if (mapped == 1)
1897 inp = in_pcblookup(&V_tcbinfo,
1898 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
1899 addrs[1].sin6_port,
1900 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
1901 addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL);
1902 else
1903 #endif
1904 inp = in6_pcblookup(&V_tcbinfo,
1905 &addrs[1].sin6_addr, addrs[1].sin6_port,
1906 &addrs[0].sin6_addr, addrs[0].sin6_port,
1907 INPLOOKUP_RLOCKPCB, NULL);
1908 if (inp != NULL) {
1909 if (inp->inp_socket == NULL)
1910 error = ENOENT;
1911 if (error == 0)
1912 error = cr_canseeinpcb(req->td->td_ucred, inp);
1913 if (error == 0)
1914 cru2x(inp->inp_cred, &xuc);
1915 INP_RUNLOCK(inp);
1916 } else
1917 error = ENOENT;
1918 if (error == 0)
1919 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
1920 return (error);
1921 }
1922
1923 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
1924 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
1925 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection");
1926 #endif /* INET6 */
1927
1928
1929 #ifdef INET
1930 void
1931 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
1932 {
1933 struct ip *ip = vip;
1934 struct tcphdr *th;
1935 struct in_addr faddr;
1936 struct inpcb *inp;
1937 struct tcpcb *tp;
1938 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
1939 struct icmp *icp;
1940 struct in_conninfo inc;
1941 tcp_seq icmp_tcp_seq;
1942 int mtu;
1943
1944 faddr = ((struct sockaddr_in *)sa)->sin_addr;
1945 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
1946 return;
1947
1948 if (cmd == PRC_MSGSIZE)
1949 notify = tcp_mtudisc_notify;
1950 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
1951 cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip)
1952 notify = tcp_drop_syn_sent;
1953
1954 /*
1955 * Hostdead is ugly because it goes linearly through all PCBs.
1956 * XXX: We never get this from ICMP, otherwise it makes an
1957 * excellent DoS attack on machines with many connections.
1958 */
1959 else if (cmd == PRC_HOSTDEAD)
1960 ip = NULL;
1961 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
1962 return;
1963
1964 if (ip == NULL) {
1965 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify);
1966 return;
1967 }
1968
1969 icp = (struct icmp *)((caddr_t)ip - offsetof(struct icmp, icmp_ip));
1970 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
1971 INP_INFO_RLOCK(&V_tcbinfo);
1972 inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport, ip->ip_src,
1973 th->th_sport, INPLOOKUP_WLOCKPCB, NULL);
1974 if (inp != NULL && PRC_IS_REDIRECT(cmd)) {
1975 /* signal EHOSTDOWN, as it flushes the cached route */
1976 inp = (*notify)(inp, EHOSTDOWN);
1977 if (inp != NULL)
1978 INP_WUNLOCK(inp);
1979 } else if (inp != NULL) {
1980 if (!(inp->inp_flags & INP_TIMEWAIT) &&
1981 !(inp->inp_flags & INP_DROPPED) &&
1982 !(inp->inp_socket == NULL)) {
1983 icmp_tcp_seq = ntohl(th->th_seq);
1984 tp = intotcpcb(inp);
1985 if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) &&
1986 SEQ_LT(icmp_tcp_seq, tp->snd_max)) {
1987 if (cmd == PRC_MSGSIZE) {
1988 /*
1989 * MTU discovery:
1990 * If we got a needfrag set the MTU
1991 * in the route to the suggested new
1992 * value (if given) and then notify.
1993 */
1994 mtu = ntohs(icp->icmp_nextmtu);
1995 /*
1996 * If no alternative MTU was
1997 * proposed, try the next smaller
1998 * one.
1999 */
2000 if (!mtu)
2001 mtu = ip_next_mtu(
2002 ntohs(ip->ip_len), 1);
2003 if (mtu < V_tcp_minmss +
2004 sizeof(struct tcpiphdr))
2005 mtu = V_tcp_minmss +
2006 sizeof(struct tcpiphdr);
2007 /*
2008 * Only process the offered MTU if it
2009 * is smaller than the current one.
2010 */
2011 if (mtu < tp->t_maxseg +
2012 sizeof(struct tcpiphdr)) {
2013 bzero(&inc, sizeof(inc));
2014 inc.inc_faddr = faddr;
2015 inc.inc_fibnum =
2016 inp->inp_inc.inc_fibnum;
2017 tcp_hc_updatemtu(&inc, mtu);
2018 tcp_mtudisc(inp, mtu);
2019 }
2020 } else
2021 inp = (*notify)(inp,
2022 inetctlerrmap[cmd]);
2023 }
2024 }
2025 if (inp != NULL)
2026 INP_WUNLOCK(inp);
2027 } else {
2028 bzero(&inc, sizeof(inc));
2029 inc.inc_fport = th->th_dport;
2030 inc.inc_lport = th->th_sport;
2031 inc.inc_faddr = faddr;
2032 inc.inc_laddr = ip->ip_src;
2033 syncache_unreach(&inc, th);
2034 }
2035 INP_INFO_RUNLOCK(&V_tcbinfo);
2036 }
2037 #endif /* INET */
2038
2039 #ifdef INET6
2040 void
2041 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
2042 {
2043 struct tcphdr th;
2044 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
2045 struct ip6_hdr *ip6;
2046 struct mbuf *m;
2047 struct ip6ctlparam *ip6cp = NULL;
2048 const struct sockaddr_in6 *sa6_src = NULL;
2049 int off;
2050 struct tcp_portonly {
2051 u_int16_t th_sport;
2052 u_int16_t th_dport;
2053 } *thp;
2054
2055 if (sa->sa_family != AF_INET6 ||
2056 sa->sa_len != sizeof(struct sockaddr_in6))
2057 return;
2058
2059 if (cmd == PRC_MSGSIZE)
2060 notify = tcp_mtudisc_notify;
2061 else if (!PRC_IS_REDIRECT(cmd) &&
2062 ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
2063 return;
2064
2065 /* if the parameter is from icmp6, decode it. */
2066 if (d != NULL) {
2067 ip6cp = (struct ip6ctlparam *)d;
2068 m = ip6cp->ip6c_m;
2069 ip6 = ip6cp->ip6c_ip6;
2070 off = ip6cp->ip6c_off;
2071 sa6_src = ip6cp->ip6c_src;
2072 } else {
2073 m = NULL;
2074 ip6 = NULL;
2075 off = 0; /* fool gcc */
2076 sa6_src = &sa6_any;
2077 }
2078
2079 if (ip6 != NULL) {
2080 struct in_conninfo inc;
2081 /*
2082 * XXX: We assume that when IPV6 is non NULL,
2083 * M and OFF are valid.
2084 */
2085
2086 /* check if we can safely examine src and dst ports */
2087 if (m->m_pkthdr.len < off + sizeof(*thp))
2088 return;
2089
2090 bzero(&th, sizeof(th));
2091 m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
2092
2093 in6_pcbnotify(&V_tcbinfo, sa, th.th_dport,
2094 (struct sockaddr *)ip6cp->ip6c_src,
2095 th.th_sport, cmd, NULL, notify);
2096
2097 bzero(&inc, sizeof(inc));
2098 inc.inc_fport = th.th_dport;
2099 inc.inc_lport = th.th_sport;
2100 inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
2101 inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
2102 inc.inc_flags |= INC_ISIPV6;
2103 INP_INFO_RLOCK(&V_tcbinfo);
2104 syncache_unreach(&inc, &th);
2105 INP_INFO_RUNLOCK(&V_tcbinfo);
2106 } else
2107 in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src,
2108 0, cmd, NULL, notify);
2109 }
2110 #endif /* INET6 */
2111
2112
2113 /*
2114 * Following is where TCP initial sequence number generation occurs.
2115 *
2116 * There are two places where we must use initial sequence numbers:
2117 * 1. In SYN-ACK packets.
2118 * 2. In SYN packets.
2119 *
2120 * All ISNs for SYN-ACK packets are generated by the syncache. See
2121 * tcp_syncache.c for details.
2122 *
2123 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
2124 * depends on this property. In addition, these ISNs should be
2125 * unguessable so as to prevent connection hijacking. To satisfy
2126 * the requirements of this situation, the algorithm outlined in
2127 * RFC 1948 is used, with only small modifications.
2128 *
2129 * Implementation details:
2130 *
2131 * Time is based off the system timer, and is corrected so that it
2132 * increases by one megabyte per second. This allows for proper
2133 * recycling on high speed LANs while still leaving over an hour
2134 * before rollover.
2135 *
2136 * As reading the *exact* system time is too expensive to be done
2137 * whenever setting up a TCP connection, we increment the time
2138 * offset in two ways. First, a small random positive increment
2139 * is added to isn_offset for each connection that is set up.
2140 * Second, the function tcp_isn_tick fires once per clock tick
2141 * and increments isn_offset as necessary so that sequence numbers
2142 * are incremented at approximately ISN_BYTES_PER_SECOND. The
2143 * random positive increments serve only to ensure that the same
2144 * exact sequence number is never sent out twice (as could otherwise
2145 * happen when a port is recycled in less than the system tick
2146 * interval.)
2147 *
2148 * net.inet.tcp.isn_reseed_interval controls the number of seconds
2149 * between seeding of isn_secret. This is normally set to zero,
2150 * as reseeding should not be necessary.
2151 *
2152 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
2153 * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock. In
2154 * general, this means holding an exclusive (write) lock.
2155 */
2156
2157 #define ISN_BYTES_PER_SECOND 1048576
2158 #define ISN_STATIC_INCREMENT 4096
2159 #define ISN_RANDOM_INCREMENT (4096 - 1)
2160
2161 static VNET_DEFINE(u_char, isn_secret[32]);
2162 static VNET_DEFINE(int, isn_last);
2163 static VNET_DEFINE(int, isn_last_reseed);
2164 static VNET_DEFINE(u_int32_t, isn_offset);
2165 static VNET_DEFINE(u_int32_t, isn_offset_old);
2166
2167 #define V_isn_secret VNET(isn_secret)
2168 #define V_isn_last VNET(isn_last)
2169 #define V_isn_last_reseed VNET(isn_last_reseed)
2170 #define V_isn_offset VNET(isn_offset)
2171 #define V_isn_offset_old VNET(isn_offset_old)
2172
2173 tcp_seq
2174 tcp_new_isn(struct tcpcb *tp)
2175 {
2176 MD5_CTX isn_ctx;
2177 u_int32_t md5_buffer[4];
2178 tcp_seq new_isn;
2179 u_int32_t projected_offset;
2180
2181 INP_WLOCK_ASSERT(tp->t_inpcb);
2182
2183 ISN_LOCK();
2184 /* Seed if this is the first use, reseed if requested. */
2185 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) &&
2186 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz)
2187 < (u_int)ticks))) {
2188 read_random(&V_isn_secret, sizeof(V_isn_secret));
2189 V_isn_last_reseed = ticks;
2190 }
2191
2192 /* Compute the md5 hash and return the ISN. */
2193 MD5Init(&isn_ctx);
2194 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
2195 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
2196 #ifdef INET6
2197 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
2198 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
2199 sizeof(struct in6_addr));
2200 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
2201 sizeof(struct in6_addr));
2202 } else
2203 #endif
2204 {
2205 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
2206 sizeof(struct in_addr));
2207 MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
2208 sizeof(struct in_addr));
2209 }
2210 MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret));
2211 MD5Final((u_char *) &md5_buffer, &isn_ctx);
2212 new_isn = (tcp_seq) md5_buffer[0];
2213 V_isn_offset += ISN_STATIC_INCREMENT +
2214 (arc4random() & ISN_RANDOM_INCREMENT);
2215 if (ticks != V_isn_last) {
2216 projected_offset = V_isn_offset_old +
2217 ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last);
2218 if (SEQ_GT(projected_offset, V_isn_offset))
2219 V_isn_offset = projected_offset;
2220 V_isn_offset_old = V_isn_offset;
2221 V_isn_last = ticks;
2222 }
2223 new_isn += V_isn_offset;
2224 ISN_UNLOCK();
2225 return (new_isn);
2226 }
2227
2228 /*
2229 * When a specific ICMP unreachable message is received and the
2230 * connection state is SYN-SENT, drop the connection. This behavior
2231 * is controlled by the icmp_may_rst sysctl.
2232 */
2233 struct inpcb *
2234 tcp_drop_syn_sent(struct inpcb *inp, int errno)
2235 {
2236 struct tcpcb *tp;
2237
2238 INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
2239 INP_WLOCK_ASSERT(inp);
2240
2241 if ((inp->inp_flags & INP_TIMEWAIT) ||
2242 (inp->inp_flags & INP_DROPPED))
2243 return (inp);
2244
2245 tp = intotcpcb(inp);
2246 if (tp->t_state != TCPS_SYN_SENT)
2247 return (inp);
2248
2249 tp = tcp_drop(tp, errno);
2250 if (tp != NULL)
2251 return (inp);
2252 else
2253 return (NULL);
2254 }
2255
2256 /*
2257 * When `need fragmentation' ICMP is received, update our idea of the MSS
2258 * based on the new value. Also nudge TCP to send something, since we
2259 * know the packet we just sent was dropped.
2260 * This duplicates some code in the tcp_mss() function in tcp_input.c.
2261 */
2262 static struct inpcb *
2263 tcp_mtudisc_notify(struct inpcb *inp, int error)
2264 {
2265
2266 tcp_mtudisc(inp, -1);
2267 return (inp);
2268 }
2269
2270 static void
2271 tcp_mtudisc(struct inpcb *inp, int mtuoffer)
2272 {
2273 struct tcpcb *tp;
2274 struct socket *so;
2275
2276 INP_WLOCK_ASSERT(inp);
2277 if ((inp->inp_flags & INP_TIMEWAIT) ||
2278 (inp->inp_flags & INP_DROPPED))
2279 return;
2280
2281 tp = intotcpcb(inp);
2282 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
2283
2284 tcp_mss_update(tp, -1, mtuoffer, NULL, NULL);
2285
2286 so = inp->inp_socket;
2287 SOCKBUF_LOCK(&so->so_snd);
2288 /* If the mss is larger than the socket buffer, decrease the mss. */
2289 if (so->so_snd.sb_hiwat < tp->t_maxseg)
2290 tp->t_maxseg = so->so_snd.sb_hiwat;
2291 SOCKBUF_UNLOCK(&so->so_snd);
2292
2293 TCPSTAT_INC(tcps_mturesent);
2294 tp->t_rtttime = 0;
2295 tp->snd_nxt = tp->snd_una;
2296 tcp_free_sackholes(tp);
2297 tp->snd_recover = tp->snd_max;
2298 if (tp->t_flags & TF_SACK_PERMIT)
2299 EXIT_FASTRECOVERY(tp->t_flags);
2300 tp->t_fb->tfb_tcp_output(tp);
2301 }
2302
2303 #ifdef INET
2304 /*
2305 * Look-up the routing entry to the peer of this inpcb. If no route
2306 * is found and it cannot be allocated, then return 0. This routine
2307 * is called by TCP routines that access the rmx structure and by
2308 * tcp_mss_update to get the peer/interface MTU.
2309 */
2310 u_long
2311 tcp_maxmtu(struct in_conninfo *inc, struct tcp_ifcap *cap)
2312 {
2313 struct nhop4_extended nh4;
2314 struct ifnet *ifp;
2315 u_long maxmtu = 0;
2316
2317 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
2318
2319 if (inc->inc_faddr.s_addr != INADDR_ANY) {
2320
2321 if (fib4_lookup_nh_ext(inc->inc_fibnum, inc->inc_faddr,
2322 NHR_REF, 0, &nh4) != 0)
2323 return (0);
2324
2325 ifp = nh4.nh_ifp;
2326 maxmtu = nh4.nh_mtu;
2327
2328 /* Report additional interface capabilities. */
2329 if (cap != NULL) {
2330 if (ifp->if_capenable & IFCAP_TSO4 &&
2331 ifp->if_hwassist & CSUM_TSO) {
2332 cap->ifcap |= CSUM_TSO;
2333 cap->tsomax = ifp->if_hw_tsomax;
2334 cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
2335 cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
2336 }
2337 }
2338 fib4_free_nh_ext(inc->inc_fibnum, &nh4);
2339 }
2340 return (maxmtu);
2341 }
2342 #endif /* INET */
2343
2344 #ifdef INET6
2345 u_long
2346 tcp_maxmtu6(struct in_conninfo *inc, struct tcp_ifcap *cap)
2347 {
2348 struct nhop6_extended nh6;
2349 struct in6_addr dst6;
2350 uint32_t scopeid;
2351 struct ifnet *ifp;
2352 u_long maxmtu = 0;
2353
2354 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
2355
2356 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
2357 in6_splitscope(&inc->inc6_faddr, &dst6, &scopeid);
2358 if (fib6_lookup_nh_ext(inc->inc_fibnum, &dst6, scopeid, 0,
2359 0, &nh6) != 0)
2360 return (0);
2361
2362 ifp = nh6.nh_ifp;
2363 maxmtu = nh6.nh_mtu;
2364
2365 /* Report additional interface capabilities. */
2366 if (cap != NULL) {
2367 if (ifp->if_capenable & IFCAP_TSO6 &&
2368 ifp->if_hwassist & CSUM_TSO) {
2369 cap->ifcap |= CSUM_TSO;
2370 cap->tsomax = ifp->if_hw_tsomax;
2371 cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
2372 cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
2373 }
2374 }
2375 fib6_free_nh_ext(inc->inc_fibnum, &nh6);
2376 }
2377
2378 return (maxmtu);
2379 }
2380 #endif /* INET6 */
2381
2382 /*
2383 * Calculate effective SMSS per RFC5681 definition for a given TCP
2384 * connection at its current state, taking into account SACK and etc.
2385 */
2386 u_int
2387 tcp_maxseg(const struct tcpcb *tp)
2388 {
2389 u_int optlen;
2390
2391 if (tp->t_flags & TF_NOOPT)
2392 return (tp->t_maxseg);
2393
2394 /*
2395 * Here we have a simplified code from tcp_addoptions(),
2396 * without a proper loop, and having most of paddings hardcoded.
2397 * We might make mistakes with padding here in some edge cases,
2398 * but this is harmless, since result of tcp_maxseg() is used
2399 * only in cwnd and ssthresh estimations.
2400 */
2401 #define PAD(len) ((((len) / 4) + !!((len) % 4)) * 4)
2402 if (TCPS_HAVEESTABLISHED(tp->t_state)) {
2403 if (tp->t_flags & TF_RCVD_TSTMP)
2404 optlen = TCPOLEN_TSTAMP_APPA;
2405 else
2406 optlen = 0;
2407 #ifdef TCP_SIGNATURE
2408 if (tp->t_flags & TF_SIGNATURE)
2409 optlen += PAD(TCPOLEN_SIGNATURE);
2410 #endif
2411 if ((tp->t_flags & TF_SACK_PERMIT) && tp->rcv_numsacks > 0) {
2412 optlen += TCPOLEN_SACKHDR;
2413 optlen += tp->rcv_numsacks * TCPOLEN_SACK;
2414 optlen = PAD(optlen);
2415 }
2416 } else {
2417 if (tp->t_flags & TF_REQ_TSTMP)
2418 optlen = TCPOLEN_TSTAMP_APPA;
2419 else
2420 optlen = PAD(TCPOLEN_MAXSEG);
2421 if (tp->t_flags & TF_REQ_SCALE)
2422 optlen += PAD(TCPOLEN_WINDOW);
2423 #ifdef TCP_SIGNATURE
2424 if (tp->t_flags & TF_SIGNATURE)
2425 optlen += PAD(TCPOLEN_SIGNATURE);
2426 #endif
2427 if (tp->t_flags & TF_SACK_PERMIT)
2428 optlen += PAD(TCPOLEN_SACK_PERMITTED);
2429 }
2430 #undef PAD
2431 optlen = min(optlen, TCP_MAXOLEN);
2432 return (tp->t_maxseg - optlen);
2433 }
2434
2435 #ifdef IPSEC
2436 /* compute ESP/AH header size for TCP, including outer IP header. */
2437 size_t
2438 ipsec_hdrsiz_tcp(struct tcpcb *tp)
2439 {
2440 struct inpcb *inp;
2441 struct mbuf *m;
2442 size_t hdrsiz;
2443 struct ip *ip;
2444 #ifdef INET6
2445 struct ip6_hdr *ip6;
2446 #endif
2447 struct tcphdr *th;
2448
2449 if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL) ||
2450 (!key_havesp(IPSEC_DIR_OUTBOUND)))
2451 return (0);
2452 m = m_gethdr(M_NOWAIT, MT_DATA);
2453 if (!m)
2454 return (0);
2455
2456 #ifdef INET6
2457 if ((inp->inp_vflag & INP_IPV6) != 0) {
2458 ip6 = mtod(m, struct ip6_hdr *);
2459 th = (struct tcphdr *)(ip6 + 1);
2460 m->m_pkthdr.len = m->m_len =
2461 sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
2462 tcpip_fillheaders(inp, ip6, th);
2463 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
2464 } else
2465 #endif /* INET6 */
2466 {
2467 ip = mtod(m, struct ip *);
2468 th = (struct tcphdr *)(ip + 1);
2469 m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
2470 tcpip_fillheaders(inp, ip, th);
2471 hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
2472 }
2473
2474 m_free(m);
2475 return (hdrsiz);
2476 }
2477 #endif /* IPSEC */
2478
2479 #ifdef TCP_SIGNATURE
2480 /*
2481 * Callback function invoked by m_apply() to digest TCP segment data
2482 * contained within an mbuf chain.
2483 */
2484 static int
2485 tcp_signature_apply(void *fstate, void *data, u_int len)
2486 {
2487
2488 MD5Update(fstate, (u_char *)data, len);
2489 return (0);
2490 }
2491
2492 /*
2493 * XXX The key is retrieved from the system's PF_KEY SADB, by keying a
2494 * search with the destination IP address, and a 'magic SPI' to be
2495 * determined by the application. This is hardcoded elsewhere to 1179
2496 */
2497 struct secasvar *
2498 tcp_get_sav(struct mbuf *m, u_int direction)
2499 {
2500 union sockaddr_union dst;
2501 struct secasvar *sav;
2502 struct ip *ip;
2503 #ifdef INET6
2504 struct ip6_hdr *ip6;
2505 char ip6buf[INET6_ADDRSTRLEN];
2506 #endif
2507
2508 /* Extract the destination from the IP header in the mbuf. */
2509 bzero(&dst, sizeof(union sockaddr_union));
2510 ip = mtod(m, struct ip *);
2511 #ifdef INET6
2512 ip6 = NULL; /* Make the compiler happy. */
2513 #endif
2514 switch (ip->ip_v) {
2515 #ifdef INET
2516 case IPVERSION:
2517 dst.sa.sa_len = sizeof(struct sockaddr_in);
2518 dst.sa.sa_family = AF_INET;
2519 dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ?
2520 ip->ip_src : ip->ip_dst;
2521 break;
2522 #endif
2523 #ifdef INET6
2524 case (IPV6_VERSION >> 4):
2525 ip6 = mtod(m, struct ip6_hdr *);
2526 dst.sa.sa_len = sizeof(struct sockaddr_in6);
2527 dst.sa.sa_family = AF_INET6;
2528 dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ?
2529 ip6->ip6_src : ip6->ip6_dst;
2530 break;
2531 #endif
2532 default:
2533 return (NULL);
2534 /* NOTREACHED */
2535 break;
2536 }
2537
2538 /* Look up an SADB entry which matches the address of the peer. */
2539 sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI));
2540 if (sav == NULL) {
2541 ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__,
2542 (ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) :
2543 #ifdef INET6
2544 (ip->ip_v == (IPV6_VERSION >> 4)) ?
2545 ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) :
2546 #endif
2547 "(unsupported)"));
2548 }
2549
2550 return (sav);
2551 }
2552
2553 /*
2554 * Compute TCP-MD5 hash of a TCP segment. (RFC2385)
2555 *
2556 * Parameters:
2557 * m pointer to head of mbuf chain
2558 * len length of TCP segment data, excluding options
2559 * optlen length of TCP segment options
2560 * buf pointer to storage for computed MD5 digest
2561 * sav pointer to security assosiation
2562 *
2563 * We do this over ip, tcphdr, segment data, and the key in the SADB.
2564 * When called from tcp_input(), we can be sure that th_sum has been
2565 * zeroed out and verified already.
2566 *
2567 * Releases reference to SADB key before return.
2568 *
2569 * Return 0 if successful, otherwise return -1.
2570 *
2571 */
2572 int
2573 tcp_signature_do_compute(struct mbuf *m, int len, int optlen,
2574 u_char *buf, struct secasvar *sav)
2575 {
2576 #ifdef INET
2577 struct ippseudo ippseudo;
2578 #endif
2579 MD5_CTX ctx;
2580 int doff;
2581 struct ip *ip;
2582 #ifdef INET
2583 struct ipovly *ipovly;
2584 #endif
2585 struct tcphdr *th;
2586 #ifdef INET6
2587 struct ip6_hdr *ip6;
2588 struct in6_addr in6;
2589 uint32_t plen;
2590 uint16_t nhdr;
2591 #endif
2592 u_short savecsum;
2593
2594 KASSERT(m != NULL, ("NULL mbuf chain"));
2595 KASSERT(buf != NULL, ("NULL signature pointer"));
2596
2597 /* Extract the destination from the IP header in the mbuf. */
2598 ip = mtod(m, struct ip *);
2599 #ifdef INET6
2600 ip6 = NULL; /* Make the compiler happy. */
2601 #endif
2602
2603 MD5Init(&ctx);
2604 /*
2605 * Step 1: Update MD5 hash with IP(v6) pseudo-header.
2606 *
2607 * XXX The ippseudo header MUST be digested in network byte order,
2608 * or else we'll fail the regression test. Assume all fields we've
2609 * been doing arithmetic on have been in host byte order.
2610 * XXX One cannot depend on ipovly->ih_len here. When called from
2611 * tcp_output(), the underlying ip_len member has not yet been set.
2612 */
2613 switch (ip->ip_v) {
2614 #ifdef INET
2615 case IPVERSION:
2616 ipovly = (struct ipovly *)ip;
2617 ippseudo.ippseudo_src = ipovly->ih_src;
2618 ippseudo.ippseudo_dst = ipovly->ih_dst;
2619 ippseudo.ippseudo_pad = 0;
2620 ippseudo.ippseudo_p = IPPROTO_TCP;
2621 ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) +
2622 optlen);
2623 MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo));
2624
2625 th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip));
2626 doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen;
2627 break;
2628 #endif
2629 #ifdef INET6
2630 /*
2631 * RFC 2385, 2.0 Proposal
2632 * For IPv6, the pseudo-header is as described in RFC 2460, namely the
2633 * 128-bit source IPv6 address, 128-bit destination IPv6 address, zero-
2634 * extended next header value (to form 32 bits), and 32-bit segment
2635 * length.
2636 * Note: Upper-Layer Packet Length comes before Next Header.
2637 */
2638 case (IPV6_VERSION >> 4):
2639 in6 = ip6->ip6_src;
2640 in6_clearscope(&in6);
2641 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
2642 in6 = ip6->ip6_dst;
2643 in6_clearscope(&in6);
2644 MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
2645 plen = htonl(len + sizeof(struct tcphdr) + optlen);
2646 MD5Update(&ctx, (char *)&plen, sizeof(uint32_t));
2647 nhdr = 0;
2648 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
2649 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
2650 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
2651 nhdr = IPPROTO_TCP;
2652 MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
2653
2654 th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr));
2655 doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen;
2656 break;
2657 #endif
2658 default:
2659 KEY_FREESAV(&sav);
2660 return (-1);
2661 /* NOTREACHED */
2662 break;
2663 }
2664
2665
2666 /*
2667 * Step 2: Update MD5 hash with TCP header, excluding options.
2668 * The TCP checksum must be set to zero.
2669 */
2670 savecsum = th->th_sum;
2671 th->th_sum = 0;
2672 MD5Update(&ctx, (char *)th, sizeof(struct tcphdr));
2673 th->th_sum = savecsum;
2674
2675 /*
2676 * Step 3: Update MD5 hash with TCP segment data.
2677 * Use m_apply() to avoid an early m_pullup().
2678 */
2679 if (len > 0)
2680 m_apply(m, doff, len, tcp_signature_apply, &ctx);
2681
2682 /*
2683 * Step 4: Update MD5 hash with shared secret.
2684 */
2685 MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth));
2686 MD5Final(buf, &ctx);
2687
2688 key_sa_recordxfer(sav, m);
2689 KEY_FREESAV(&sav);
2690 return (0);
2691 }
2692
2693 /*
2694 * Compute TCP-MD5 hash of a TCP segment. (RFC2385)
2695 *
2696 * Return 0 if successful, otherwise return -1.
2697 */
2698 int
2699 tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen,
2700 u_char *buf, u_int direction)
2701 {
2702 struct secasvar *sav;
2703
2704 if ((sav = tcp_get_sav(m, direction)) == NULL)
2705 return (-1);
2706
2707 return (tcp_signature_do_compute(m, len, optlen, buf, sav));
2708 }
2709
2710 /*
2711 * Verify the TCP-MD5 hash of a TCP segment. (RFC2385)
2712 *
2713 * Parameters:
2714 * m pointer to head of mbuf chain
2715 * len length of TCP segment data, excluding options
2716 * optlen length of TCP segment options
2717 * buf pointer to storage for computed MD5 digest
2718 * direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND)
2719 *
2720 * Return 1 if successful, otherwise return 0.
2721 */
2722 int
2723 tcp_signature_verify(struct mbuf *m, int off0, int tlen, int optlen,
2724 struct tcpopt *to, struct tcphdr *th, u_int tcpbflag)
2725 {
2726 char tmpdigest[TCP_SIGLEN];
2727
2728 if (tcp_sig_checksigs == 0)
2729 return (1);
2730 if ((tcpbflag & TF_SIGNATURE) == 0) {
2731 if ((to->to_flags & TOF_SIGNATURE) != 0) {
2732
2733 /*
2734 * If this socket is not expecting signature but
2735 * the segment contains signature just fail.
2736 */
2737 TCPSTAT_INC(tcps_sig_err_sigopt);
2738 TCPSTAT_INC(tcps_sig_rcvbadsig);
2739 return (0);
2740 }
2741
2742 /* Signature is not expected, and not present in segment. */
2743 return (1);
2744 }
2745
2746 /*
2747 * If this socket is expecting signature but the segment does not
2748 * contain any just fail.
2749 */
2750 if ((to->to_flags & TOF_SIGNATURE) == 0) {
2751 TCPSTAT_INC(tcps_sig_err_nosigopt);
2752 TCPSTAT_INC(tcps_sig_rcvbadsig);
2753 return (0);
2754 }
2755 if (tcp_signature_compute(m, off0, tlen, optlen, &tmpdigest[0],
2756 IPSEC_DIR_INBOUND) == -1) {
2757 TCPSTAT_INC(tcps_sig_err_buildsig);
2758 TCPSTAT_INC(tcps_sig_rcvbadsig);
2759 return (0);
2760 }
2761
2762 if (bcmp(to->to_signature, &tmpdigest[0], TCP_SIGLEN) != 0) {
2763 TCPSTAT_INC(tcps_sig_rcvbadsig);
2764 return (0);
2765 }
2766 TCPSTAT_INC(tcps_sig_rcvgoodsig);
2767 return (1);
2768 }
2769 #endif /* TCP_SIGNATURE */
2770
2771 static int
2772 sysctl_drop(SYSCTL_HANDLER_ARGS)
2773 {
2774 /* addrs[0] is a foreign socket, addrs[1] is a local one. */
2775 struct sockaddr_storage addrs[2];
2776 struct inpcb *inp;
2777 struct tcpcb *tp;
2778 struct tcptw *tw;
2779 struct sockaddr_in *fin, *lin;
2780 #ifdef INET6
2781 struct sockaddr_in6 *fin6, *lin6;
2782 #endif
2783 int error;
2784
2785 inp = NULL;
2786 fin = lin = NULL;
2787 #ifdef INET6
2788 fin6 = lin6 = NULL;
2789 #endif
2790 error = 0;
2791
2792 if (req->oldptr != NULL || req->oldlen != 0)
2793 return (EINVAL);
2794 if (req->newptr == NULL)
2795 return (EPERM);
2796 if (req->newlen < sizeof(addrs))
2797 return (ENOMEM);
2798 error = SYSCTL_IN(req, &addrs, sizeof(addrs));
2799 if (error)
2800 return (error);
2801
2802 switch (addrs[0].ss_family) {
2803 #ifdef INET6
2804 case AF_INET6:
2805 fin6 = (struct sockaddr_in6 *)&addrs[0];
2806 lin6 = (struct sockaddr_in6 *)&addrs[1];
2807 if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
2808 lin6->sin6_len != sizeof(struct sockaddr_in6))
2809 return (EINVAL);
2810 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
2811 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
2812 return (EINVAL);
2813 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
2814 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
2815 fin = (struct sockaddr_in *)&addrs[0];
2816 lin = (struct sockaddr_in *)&addrs[1];
2817 break;
2818 }
2819 error = sa6_embedscope(fin6, V_ip6_use_defzone);
2820 if (error)
2821 return (error);
2822 error = sa6_embedscope(lin6, V_ip6_use_defzone);
2823 if (error)
2824 return (error);
2825 break;
2826 #endif
2827 #ifdef INET
2828 case AF_INET:
2829 fin = (struct sockaddr_in *)&addrs[0];
2830 lin = (struct sockaddr_in *)&addrs[1];
2831 if (fin->sin_len != sizeof(struct sockaddr_in) ||
2832 lin->sin_len != sizeof(struct sockaddr_in))
2833 return (EINVAL);
2834 break;
2835 #endif
2836 default:
2837 return (EINVAL);
2838 }
2839 INP_INFO_RLOCK(&V_tcbinfo);
2840 switch (addrs[0].ss_family) {
2841 #ifdef INET6
2842 case AF_INET6:
2843 inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
2844 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
2845 INPLOOKUP_WLOCKPCB, NULL);
2846 break;
2847 #endif
2848 #ifdef INET
2849 case AF_INET:
2850 inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
2851 lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
2852 break;
2853 #endif
2854 }
2855 if (inp != NULL) {
2856 if (inp->inp_flags & INP_TIMEWAIT) {
2857 /*
2858 * XXXRW: There currently exists a state where an
2859 * inpcb is present, but its timewait state has been
2860 * discarded. For now, don't allow dropping of this
2861 * type of inpcb.
2862 */
2863 tw = intotw(inp);
2864 if (tw != NULL)
2865 tcp_twclose(tw, 0);
2866 else
2867 INP_WUNLOCK(inp);
2868 } else if (!(inp->inp_flags & INP_DROPPED) &&
2869 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) {
2870 tp = intotcpcb(inp);
2871 tp = tcp_drop(tp, ECONNABORTED);
2872 if (tp != NULL)
2873 INP_WUNLOCK(inp);
2874 } else
2875 INP_WUNLOCK(inp);
2876 } else
2877 error = ESRCH;
2878 INP_INFO_RUNLOCK(&V_tcbinfo);
2879 return (error);
2880 }
2881
2882 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
2883 CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP, NULL,
2884 0, sysctl_drop, "", "Drop TCP connection");
2885
2886 /*
2887 * Generate a standardized TCP log line for use throughout the
2888 * tcp subsystem. Memory allocation is done with M_NOWAIT to
2889 * allow use in the interrupt context.
2890 *
2891 * NB: The caller MUST free(s, M_TCPLOG) the returned string.
2892 * NB: The function may return NULL if memory allocation failed.
2893 *
2894 * Due to header inclusion and ordering limitations the struct ip
2895 * and ip6_hdr pointers have to be passed as void pointers.
2896 */
2897 char *
2898 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2899 const void *ip6hdr)
2900 {
2901
2902 /* Is logging enabled? */
2903 if (tcp_log_in_vain == 0)
2904 return (NULL);
2905
2906 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
2907 }
2908
2909 char *
2910 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2911 const void *ip6hdr)
2912 {
2913
2914 /* Is logging enabled? */
2915 if (tcp_log_debug == 0)
2916 return (NULL);
2917
2918 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
2919 }
2920
2921 static char *
2922 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
2923 const void *ip6hdr)
2924 {
2925 char *s, *sp;
2926 size_t size;
2927 struct ip *ip;
2928 #ifdef INET6
2929 const struct ip6_hdr *ip6;
2930
2931 ip6 = (const struct ip6_hdr *)ip6hdr;
2932 #endif /* INET6 */
2933 ip = (struct ip *)ip4hdr;
2934
2935 /*
2936 * The log line looks like this:
2937 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>"
2938 */
2939 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") +
2940 sizeof(PRINT_TH_FLAGS) + 1 +
2941 #ifdef INET6
2942 2 * INET6_ADDRSTRLEN;
2943 #else
2944 2 * INET_ADDRSTRLEN;
2945 #endif /* INET6 */
2946
2947 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT);
2948 if (s == NULL)
2949 return (NULL);
2950
2951 strcat(s, "TCP: [");
2952 sp = s + strlen(s);
2953
2954 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) {
2955 inet_ntoa_r(inc->inc_faddr, sp);
2956 sp = s + strlen(s);
2957 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2958 sp = s + strlen(s);
2959 inet_ntoa_r(inc->inc_laddr, sp);
2960 sp = s + strlen(s);
2961 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2962 #ifdef INET6
2963 } else if (inc) {
2964 ip6_sprintf(sp, &inc->inc6_faddr);
2965 sp = s + strlen(s);
2966 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
2967 sp = s + strlen(s);
2968 ip6_sprintf(sp, &inc->inc6_laddr);
2969 sp = s + strlen(s);
2970 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
2971 } else if (ip6 && th) {
2972 ip6_sprintf(sp, &ip6->ip6_src);
2973 sp = s + strlen(s);
2974 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2975 sp = s + strlen(s);
2976 ip6_sprintf(sp, &ip6->ip6_dst);
2977 sp = s + strlen(s);
2978 sprintf(sp, "]:%i", ntohs(th->th_dport));
2979 #endif /* INET6 */
2980 #ifdef INET
2981 } else if (ip && th) {
2982 inet_ntoa_r(ip->ip_src, sp);
2983 sp = s + strlen(s);
2984 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
2985 sp = s + strlen(s);
2986 inet_ntoa_r(ip->ip_dst, sp);
2987 sp = s + strlen(s);
2988 sprintf(sp, "]:%i", ntohs(th->th_dport));
2989 #endif /* INET */
2990 } else {
2991 free(s, M_TCPLOG);
2992 return (NULL);
2993 }
2994 sp = s + strlen(s);
2995 if (th)
2996 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS);
2997 if (*(s + size - 1) != '\0')
2998 panic("%s: string too long", __func__);
2999 return (s);
3000 }
3001
3002 /*
3003 * A subroutine which makes it easy to track TCP state changes with DTrace.
3004 * This function shouldn't be called for t_state initializations that don't
3005 * correspond to actual TCP state transitions.
3006 */
3007 void
3008 tcp_state_change(struct tcpcb *tp, int newstate)
3009 {
3010 #if defined(KDTRACE_HOOKS)
3011 int pstate = tp->t_state;
3012 #endif
3013
3014 TCPSTATES_DEC(tp->t_state);
3015 TCPSTATES_INC(newstate);
3016 tp->t_state = newstate;
3017 TCP_PROBE6(state__change, NULL, tp, NULL, tp, NULL, pstate);
3018 }
Cache object: 8df19b644dae1ae4550370008635a6f1
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