1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
5 * The Regents of the University of California. 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 University 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 REGENTS 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 REGENTS 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 * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
32 */
33
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD: releng/12.0/sys/netinet/tcp_subr.c 340980 2018-11-26 16:36:38Z markj $");
36
37 #include "opt_inet.h"
38 #include "opt_inet6.h"
39 #include "opt_ipsec.h"
40 #include "opt_tcpdebug.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/callout.h>
45 #include <sys/eventhandler.h>
46 #ifdef TCP_HHOOK
47 #include <sys/hhook.h>
48 #endif
49 #include <sys/kernel.h>
50 #ifdef TCP_HHOOK
51 #include <sys/khelp.h>
52 #endif
53 #include <sys/sysctl.h>
54 #include <sys/jail.h>
55 #include <sys/malloc.h>
56 #include <sys/refcount.h>
57 #include <sys/mbuf.h>
58 #ifdef INET6
59 #include <sys/domain.h>
60 #endif
61 #include <sys/priv.h>
62 #include <sys/proc.h>
63 #include <sys/sdt.h>
64 #include <sys/socket.h>
65 #include <sys/socketvar.h>
66 #include <sys/protosw.h>
67 #include <sys/random.h>
68
69 #include <vm/uma.h>
70
71 #include <net/route.h>
72 #include <net/if.h>
73 #include <net/if_var.h>
74 #include <net/vnet.h>
75
76 #include <netinet/in.h>
77 #include <netinet/in_fib.h>
78 #include <netinet/in_kdtrace.h>
79 #include <netinet/in_pcb.h>
80 #include <netinet/in_systm.h>
81 #include <netinet/in_var.h>
82 #include <netinet/ip.h>
83 #include <netinet/ip_icmp.h>
84 #include <netinet/ip_var.h>
85 #ifdef INET6
86 #include <netinet/icmp6.h>
87 #include <netinet/ip6.h>
88 #include <netinet6/in6_fib.h>
89 #include <netinet6/in6_pcb.h>
90 #include <netinet6/ip6_var.h>
91 #include <netinet6/scope6_var.h>
92 #include <netinet6/nd6.h>
93 #endif
94
95 #include <netinet/tcp.h>
96 #include <netinet/tcp_fsm.h>
97 #include <netinet/tcp_seq.h>
98 #include <netinet/tcp_timer.h>
99 #include <netinet/tcp_var.h>
100 #include <netinet/tcp_log_buf.h>
101 #include <netinet/tcp_syncache.h>
102 #include <netinet/tcp_hpts.h>
103 #include <netinet/cc/cc.h>
104 #ifdef INET6
105 #include <netinet6/tcp6_var.h>
106 #endif
107 #include <netinet/tcpip.h>
108 #include <netinet/tcp_fastopen.h>
109 #ifdef TCPPCAP
110 #include <netinet/tcp_pcap.h>
111 #endif
112 #ifdef TCPDEBUG
113 #include <netinet/tcp_debug.h>
114 #endif
115 #ifdef INET6
116 #include <netinet6/ip6protosw.h>
117 #endif
118 #ifdef TCP_OFFLOAD
119 #include <netinet/tcp_offload.h>
120 #endif
121
122 #include <netipsec/ipsec_support.h>
123
124 #include <machine/in_cksum.h>
125 #include <sys/md5.h>
126
127 #include <security/mac/mac_framework.h>
128
129 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS;
130 #ifdef INET6
131 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS;
132 #endif
133
134 struct rwlock tcp_function_lock;
135
136 static int
137 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
138 {
139 int error, new;
140
141 new = V_tcp_mssdflt;
142 error = sysctl_handle_int(oidp, &new, 0, req);
143 if (error == 0 && req->newptr) {
144 if (new < TCP_MINMSS)
145 error = EINVAL;
146 else
147 V_tcp_mssdflt = new;
148 }
149 return (error);
150 }
151
152 SYSCTL_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
153 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW, &VNET_NAME(tcp_mssdflt), 0,
154 &sysctl_net_inet_tcp_mss_check, "I",
155 "Default TCP Maximum Segment Size");
156
157 #ifdef INET6
158 static int
159 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS)
160 {
161 int error, new;
162
163 new = V_tcp_v6mssdflt;
164 error = sysctl_handle_int(oidp, &new, 0, req);
165 if (error == 0 && req->newptr) {
166 if (new < TCP_MINMSS)
167 error = EINVAL;
168 else
169 V_tcp_v6mssdflt = new;
170 }
171 return (error);
172 }
173
174 SYSCTL_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
175 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW, &VNET_NAME(tcp_v6mssdflt), 0,
176 &sysctl_net_inet_tcp_mss_v6_check, "I",
177 "Default TCP Maximum Segment Size for IPv6");
178 #endif /* INET6 */
179
180 /*
181 * Minimum MSS we accept and use. This prevents DoS attacks where
182 * we are forced to a ridiculous low MSS like 20 and send hundreds
183 * of packets instead of one. The effect scales with the available
184 * bandwidth and quickly saturates the CPU and network interface
185 * with packet generation and sending. Set to zero to disable MINMSS
186 * checking. This setting prevents us from sending too small packets.
187 */
188 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS;
189 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_VNET | CTLFLAG_RW,
190 &VNET_NAME(tcp_minmss), 0,
191 "Minimum TCP Maximum Segment Size");
192
193 VNET_DEFINE(int, tcp_do_rfc1323) = 1;
194 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_VNET | CTLFLAG_RW,
195 &VNET_NAME(tcp_do_rfc1323), 0,
196 "Enable rfc1323 (high performance TCP) extensions");
197
198 static int tcp_log_debug = 0;
199 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW,
200 &tcp_log_debug, 0, "Log errors caused by incoming TCP segments");
201
202 static int tcp_tcbhashsize;
203 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
204 &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
205
206 static int do_tcpdrain = 1;
207 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
208 "Enable tcp_drain routine for extra help when low on mbufs");
209
210 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_VNET | CTLFLAG_RD,
211 &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
212
213 VNET_DEFINE_STATIC(int, icmp_may_rst) = 1;
214 #define V_icmp_may_rst VNET(icmp_may_rst)
215 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_VNET | CTLFLAG_RW,
216 &VNET_NAME(icmp_may_rst), 0,
217 "Certain ICMP unreachable messages may abort connections in SYN_SENT");
218
219 VNET_DEFINE_STATIC(int, tcp_isn_reseed_interval) = 0;
220 #define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval)
221 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_VNET | CTLFLAG_RW,
222 &VNET_NAME(tcp_isn_reseed_interval), 0,
223 "Seconds between reseeding of ISN secret");
224
225 static int tcp_soreceive_stream;
226 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
227 &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
228
229 VNET_DEFINE(uma_zone_t, sack_hole_zone);
230 #define V_sack_hole_zone VNET(sack_hole_zone)
231
232 #ifdef TCP_HHOOK
233 VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]);
234 #endif
235
236 #define TS_OFFSET_SECRET_LENGTH 32
237 VNET_DEFINE_STATIC(u_char, ts_offset_secret[TS_OFFSET_SECRET_LENGTH]);
238 #define V_ts_offset_secret VNET(ts_offset_secret)
239
240 static int tcp_default_fb_init(struct tcpcb *tp);
241 static void tcp_default_fb_fini(struct tcpcb *tp, int tcb_is_purged);
242 static int tcp_default_handoff_ok(struct tcpcb *tp);
243 static struct inpcb *tcp_notify(struct inpcb *, int);
244 static struct inpcb *tcp_mtudisc_notify(struct inpcb *, int);
245 static void tcp_mtudisc(struct inpcb *, int);
246 static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th,
247 void *ip4hdr, const void *ip6hdr);
248
249
250 static struct tcp_function_block tcp_def_funcblk = {
251 .tfb_tcp_block_name = "freebsd",
252 .tfb_tcp_output = tcp_output,
253 .tfb_tcp_do_segment = tcp_do_segment,
254 .tfb_tcp_ctloutput = tcp_default_ctloutput,
255 .tfb_tcp_handoff_ok = tcp_default_handoff_ok,
256 .tfb_tcp_fb_init = tcp_default_fb_init,
257 .tfb_tcp_fb_fini = tcp_default_fb_fini,
258 };
259
260 int t_functions_inited = 0;
261 static int tcp_fb_cnt = 0;
262 struct tcp_funchead t_functions;
263 static struct tcp_function_block *tcp_func_set_ptr = &tcp_def_funcblk;
264
265 static void
266 init_tcp_functions(void)
267 {
268 if (t_functions_inited == 0) {
269 TAILQ_INIT(&t_functions);
270 rw_init_flags(&tcp_function_lock, "tcp_func_lock" , 0);
271 t_functions_inited = 1;
272 }
273 }
274
275 static struct tcp_function_block *
276 find_tcp_functions_locked(struct tcp_function_set *fs)
277 {
278 struct tcp_function *f;
279 struct tcp_function_block *blk=NULL;
280
281 TAILQ_FOREACH(f, &t_functions, tf_next) {
282 if (strcmp(f->tf_name, fs->function_set_name) == 0) {
283 blk = f->tf_fb;
284 break;
285 }
286 }
287 return(blk);
288 }
289
290 static struct tcp_function_block *
291 find_tcp_fb_locked(struct tcp_function_block *blk, struct tcp_function **s)
292 {
293 struct tcp_function_block *rblk=NULL;
294 struct tcp_function *f;
295
296 TAILQ_FOREACH(f, &t_functions, tf_next) {
297 if (f->tf_fb == blk) {
298 rblk = blk;
299 if (s) {
300 *s = f;
301 }
302 break;
303 }
304 }
305 return (rblk);
306 }
307
308 struct tcp_function_block *
309 find_and_ref_tcp_functions(struct tcp_function_set *fs)
310 {
311 struct tcp_function_block *blk;
312
313 rw_rlock(&tcp_function_lock);
314 blk = find_tcp_functions_locked(fs);
315 if (blk)
316 refcount_acquire(&blk->tfb_refcnt);
317 rw_runlock(&tcp_function_lock);
318 return(blk);
319 }
320
321 struct tcp_function_block *
322 find_and_ref_tcp_fb(struct tcp_function_block *blk)
323 {
324 struct tcp_function_block *rblk;
325
326 rw_rlock(&tcp_function_lock);
327 rblk = find_tcp_fb_locked(blk, NULL);
328 if (rblk)
329 refcount_acquire(&rblk->tfb_refcnt);
330 rw_runlock(&tcp_function_lock);
331 return(rblk);
332 }
333
334 static struct tcp_function_block *
335 find_and_ref_tcp_default_fb(void)
336 {
337 struct tcp_function_block *rblk;
338
339 rw_rlock(&tcp_function_lock);
340 rblk = tcp_func_set_ptr;
341 refcount_acquire(&rblk->tfb_refcnt);
342 rw_runlock(&tcp_function_lock);
343 return (rblk);
344 }
345
346 void
347 tcp_switch_back_to_default(struct tcpcb *tp)
348 {
349 struct tcp_function_block *tfb;
350
351 KASSERT(tp->t_fb != &tcp_def_funcblk,
352 ("%s: called by the built-in default stack", __func__));
353
354 /*
355 * Release the old stack. This function will either find a new one
356 * or panic.
357 */
358 if (tp->t_fb->tfb_tcp_fb_fini != NULL)
359 (*tp->t_fb->tfb_tcp_fb_fini)(tp, 0);
360 refcount_release(&tp->t_fb->tfb_refcnt);
361
362 /*
363 * Now, we'll find a new function block to use.
364 * Start by trying the current user-selected
365 * default, unless this stack is the user-selected
366 * default.
367 */
368 tfb = find_and_ref_tcp_default_fb();
369 if (tfb == tp->t_fb) {
370 refcount_release(&tfb->tfb_refcnt);
371 tfb = NULL;
372 }
373 /* Does the stack accept this connection? */
374 if (tfb != NULL && tfb->tfb_tcp_handoff_ok != NULL &&
375 (*tfb->tfb_tcp_handoff_ok)(tp)) {
376 refcount_release(&tfb->tfb_refcnt);
377 tfb = NULL;
378 }
379 /* Try to use that stack. */
380 if (tfb != NULL) {
381 /* Initialize the new stack. If it succeeds, we are done. */
382 tp->t_fb = tfb;
383 if (tp->t_fb->tfb_tcp_fb_init == NULL ||
384 (*tp->t_fb->tfb_tcp_fb_init)(tp) == 0)
385 return;
386
387 /*
388 * Initialization failed. Release the reference count on
389 * the stack.
390 */
391 refcount_release(&tfb->tfb_refcnt);
392 }
393
394 /*
395 * If that wasn't feasible, use the built-in default
396 * stack which is not allowed to reject anyone.
397 */
398 tfb = find_and_ref_tcp_fb(&tcp_def_funcblk);
399 if (tfb == NULL) {
400 /* there always should be a default */
401 panic("Can't refer to tcp_def_funcblk");
402 }
403 if (tfb->tfb_tcp_handoff_ok != NULL) {
404 if ((*tfb->tfb_tcp_handoff_ok) (tp)) {
405 /* The default stack cannot say no */
406 panic("Default stack rejects a new session?");
407 }
408 }
409 tp->t_fb = tfb;
410 if (tp->t_fb->tfb_tcp_fb_init != NULL &&
411 (*tp->t_fb->tfb_tcp_fb_init)(tp)) {
412 /* The default stack cannot fail */
413 panic("Default stack initialization failed");
414 }
415 }
416
417 static int
418 sysctl_net_inet_default_tcp_functions(SYSCTL_HANDLER_ARGS)
419 {
420 int error=ENOENT;
421 struct tcp_function_set fs;
422 struct tcp_function_block *blk;
423
424 memset(&fs, 0, sizeof(fs));
425 rw_rlock(&tcp_function_lock);
426 blk = find_tcp_fb_locked(tcp_func_set_ptr, NULL);
427 if (blk) {
428 /* Found him */
429 strcpy(fs.function_set_name, blk->tfb_tcp_block_name);
430 fs.pcbcnt = blk->tfb_refcnt;
431 }
432 rw_runlock(&tcp_function_lock);
433 error = sysctl_handle_string(oidp, fs.function_set_name,
434 sizeof(fs.function_set_name), req);
435
436 /* Check for error or no change */
437 if (error != 0 || req->newptr == NULL)
438 return(error);
439
440 rw_wlock(&tcp_function_lock);
441 blk = find_tcp_functions_locked(&fs);
442 if ((blk == NULL) ||
443 (blk->tfb_flags & TCP_FUNC_BEING_REMOVED)) {
444 error = ENOENT;
445 goto done;
446 }
447 tcp_func_set_ptr = blk;
448 done:
449 rw_wunlock(&tcp_function_lock);
450 return (error);
451 }
452
453 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_default,
454 CTLTYPE_STRING | CTLFLAG_RW,
455 NULL, 0, sysctl_net_inet_default_tcp_functions, "A",
456 "Set/get the default TCP functions");
457
458 static int
459 sysctl_net_inet_list_available(SYSCTL_HANDLER_ARGS)
460 {
461 int error, cnt, linesz;
462 struct tcp_function *f;
463 char *buffer, *cp;
464 size_t bufsz, outsz;
465 bool alias;
466
467 cnt = 0;
468 rw_rlock(&tcp_function_lock);
469 TAILQ_FOREACH(f, &t_functions, tf_next) {
470 cnt++;
471 }
472 rw_runlock(&tcp_function_lock);
473
474 bufsz = (cnt+2) * ((TCP_FUNCTION_NAME_LEN_MAX * 2) + 13) + 1;
475 buffer = malloc(bufsz, M_TEMP, M_WAITOK);
476
477 error = 0;
478 cp = buffer;
479
480 linesz = snprintf(cp, bufsz, "\n%-32s%c %-32s %s\n", "Stack", 'D',
481 "Alias", "PCB count");
482 cp += linesz;
483 bufsz -= linesz;
484 outsz = linesz;
485
486 rw_rlock(&tcp_function_lock);
487 TAILQ_FOREACH(f, &t_functions, tf_next) {
488 alias = (f->tf_name != f->tf_fb->tfb_tcp_block_name);
489 linesz = snprintf(cp, bufsz, "%-32s%c %-32s %u\n",
490 f->tf_fb->tfb_tcp_block_name,
491 (f->tf_fb == tcp_func_set_ptr) ? '*' : ' ',
492 alias ? f->tf_name : "-",
493 f->tf_fb->tfb_refcnt);
494 if (linesz >= bufsz) {
495 error = EOVERFLOW;
496 break;
497 }
498 cp += linesz;
499 bufsz -= linesz;
500 outsz += linesz;
501 }
502 rw_runlock(&tcp_function_lock);
503 if (error == 0)
504 error = sysctl_handle_string(oidp, buffer, outsz + 1, req);
505 free(buffer, M_TEMP);
506 return (error);
507 }
508
509 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_available,
510 CTLTYPE_STRING|CTLFLAG_RD,
511 NULL, 0, sysctl_net_inet_list_available, "A",
512 "list available TCP Function sets");
513
514 /*
515 * Exports one (struct tcp_function_info) for each alias/name.
516 */
517 static int
518 sysctl_net_inet_list_func_info(SYSCTL_HANDLER_ARGS)
519 {
520 int cnt, error;
521 struct tcp_function *f;
522 struct tcp_function_info tfi;
523
524 /*
525 * We don't allow writes.
526 */
527 if (req->newptr != NULL)
528 return (EINVAL);
529
530 /*
531 * Wire the old buffer so we can directly copy the functions to
532 * user space without dropping the lock.
533 */
534 if (req->oldptr != NULL) {
535 error = sysctl_wire_old_buffer(req, 0);
536 if (error)
537 return (error);
538 }
539
540 /*
541 * Walk the list and copy out matching entries. If INVARIANTS
542 * is compiled in, also walk the list to verify the length of
543 * the list matches what we have recorded.
544 */
545 rw_rlock(&tcp_function_lock);
546
547 cnt = 0;
548 #ifndef INVARIANTS
549 if (req->oldptr == NULL) {
550 cnt = tcp_fb_cnt;
551 goto skip_loop;
552 }
553 #endif
554 TAILQ_FOREACH(f, &t_functions, tf_next) {
555 #ifdef INVARIANTS
556 cnt++;
557 #endif
558 if (req->oldptr != NULL) {
559 bzero(&tfi, sizeof(tfi));
560 tfi.tfi_refcnt = f->tf_fb->tfb_refcnt;
561 tfi.tfi_id = f->tf_fb->tfb_id;
562 (void)strncpy(tfi.tfi_alias, f->tf_name,
563 TCP_FUNCTION_NAME_LEN_MAX);
564 tfi.tfi_alias[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
565 (void)strncpy(tfi.tfi_name,
566 f->tf_fb->tfb_tcp_block_name,
567 TCP_FUNCTION_NAME_LEN_MAX);
568 tfi.tfi_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
569 error = SYSCTL_OUT(req, &tfi, sizeof(tfi));
570 /*
571 * Don't stop on error, as that is the
572 * mechanism we use to accumulate length
573 * information if the buffer was too short.
574 */
575 }
576 }
577 KASSERT(cnt == tcp_fb_cnt,
578 ("%s: cnt (%d) != tcp_fb_cnt (%d)", __func__, cnt, tcp_fb_cnt));
579 #ifndef INVARIANTS
580 skip_loop:
581 #endif
582 rw_runlock(&tcp_function_lock);
583 if (req->oldptr == NULL)
584 error = SYSCTL_OUT(req, NULL,
585 (cnt + 1) * sizeof(struct tcp_function_info));
586
587 return (error);
588 }
589
590 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, function_info,
591 CTLTYPE_OPAQUE | CTLFLAG_SKIP | CTLFLAG_RD | CTLFLAG_MPSAFE,
592 NULL, 0, sysctl_net_inet_list_func_info, "S,tcp_function_info",
593 "List TCP function block name-to-ID mappings");
594
595 /*
596 * tfb_tcp_handoff_ok() function for the default stack.
597 * Note that we'll basically try to take all comers.
598 */
599 static int
600 tcp_default_handoff_ok(struct tcpcb *tp)
601 {
602
603 return (0);
604 }
605
606 /*
607 * tfb_tcp_fb_init() function for the default stack.
608 *
609 * This handles making sure we have appropriate timers set if you are
610 * transitioning a socket that has some amount of setup done.
611 *
612 * The init() fuction from the default can *never* return non-zero i.e.
613 * it is required to always succeed since it is the stack of last resort!
614 */
615 static int
616 tcp_default_fb_init(struct tcpcb *tp)
617 {
618
619 struct socket *so;
620
621 INP_WLOCK_ASSERT(tp->t_inpcb);
622
623 KASSERT(tp->t_state >= 0 && tp->t_state < TCPS_TIME_WAIT,
624 ("%s: connection %p in unexpected state %d", __func__, tp,
625 tp->t_state));
626
627 /*
628 * Nothing to do for ESTABLISHED or LISTEN states. And, we don't
629 * know what to do for unexpected states (which includes TIME_WAIT).
630 */
631 if (tp->t_state <= TCPS_LISTEN || tp->t_state >= TCPS_TIME_WAIT)
632 return (0);
633
634 /*
635 * Make sure some kind of transmission timer is set if there is
636 * outstanding data.
637 */
638 so = tp->t_inpcb->inp_socket;
639 if ((!TCPS_HAVEESTABLISHED(tp->t_state) || sbavail(&so->so_snd) ||
640 tp->snd_una != tp->snd_max) && !(tcp_timer_active(tp, TT_REXMT) ||
641 tcp_timer_active(tp, TT_PERSIST))) {
642 /*
643 * If the session has established and it looks like it should
644 * be in the persist state, set the persist timer. Otherwise,
645 * set the retransmit timer.
646 */
647 if (TCPS_HAVEESTABLISHED(tp->t_state) && tp->snd_wnd == 0 &&
648 (int32_t)(tp->snd_nxt - tp->snd_una) <
649 (int32_t)sbavail(&so->so_snd))
650 tcp_setpersist(tp);
651 else
652 tcp_timer_activate(tp, TT_REXMT, tp->t_rxtcur);
653 }
654
655 /* All non-embryonic sessions get a keepalive timer. */
656 if (!tcp_timer_active(tp, TT_KEEP))
657 tcp_timer_activate(tp, TT_KEEP,
658 TCPS_HAVEESTABLISHED(tp->t_state) ? TP_KEEPIDLE(tp) :
659 TP_KEEPINIT(tp));
660
661 return (0);
662 }
663
664 /*
665 * tfb_tcp_fb_fini() function for the default stack.
666 *
667 * This changes state as necessary (or prudent) to prepare for another stack
668 * to assume responsibility for the connection.
669 */
670 static void
671 tcp_default_fb_fini(struct tcpcb *tp, int tcb_is_purged)
672 {
673
674 INP_WLOCK_ASSERT(tp->t_inpcb);
675 return;
676 }
677
678 /*
679 * Target size of TCP PCB hash tables. Must be a power of two.
680 *
681 * Note that this can be overridden by the kernel environment
682 * variable net.inet.tcp.tcbhashsize
683 */
684 #ifndef TCBHASHSIZE
685 #define TCBHASHSIZE 0
686 #endif
687
688 /*
689 * XXX
690 * Callouts should be moved into struct tcp directly. They are currently
691 * separate because the tcpcb structure is exported to userland for sysctl
692 * parsing purposes, which do not know about callouts.
693 */
694 struct tcpcb_mem {
695 struct tcpcb tcb;
696 struct tcp_timer tt;
697 struct cc_var ccv;
698 #ifdef TCP_HHOOK
699 struct osd osd;
700 #endif
701 };
702
703 VNET_DEFINE_STATIC(uma_zone_t, tcpcb_zone);
704 #define V_tcpcb_zone VNET(tcpcb_zone)
705
706 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
707 MALLOC_DEFINE(M_TCPFUNCTIONS, "tcpfunc", "TCP function set memory");
708
709 static struct mtx isn_mtx;
710
711 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF)
712 #define ISN_LOCK() mtx_lock(&isn_mtx)
713 #define ISN_UNLOCK() mtx_unlock(&isn_mtx)
714
715 /*
716 * TCP initialization.
717 */
718 static void
719 tcp_zone_change(void *tag)
720 {
721
722 uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets);
723 uma_zone_set_max(V_tcpcb_zone, maxsockets);
724 tcp_tw_zone_change();
725 }
726
727 static int
728 tcp_inpcb_init(void *mem, int size, int flags)
729 {
730 struct inpcb *inp = mem;
731
732 INP_LOCK_INIT(inp, "inp", "tcpinp");
733 return (0);
734 }
735
736 /*
737 * Take a value and get the next power of 2 that doesn't overflow.
738 * Used to size the tcp_inpcb hash buckets.
739 */
740 static int
741 maketcp_hashsize(int size)
742 {
743 int hashsize;
744
745 /*
746 * auto tune.
747 * get the next power of 2 higher than maxsockets.
748 */
749 hashsize = 1 << fls(size);
750 /* catch overflow, and just go one power of 2 smaller */
751 if (hashsize < size) {
752 hashsize = 1 << (fls(size) - 1);
753 }
754 return (hashsize);
755 }
756
757 static volatile int next_tcp_stack_id = 1;
758
759 /*
760 * Register a TCP function block with the name provided in the names
761 * array. (Note that this function does NOT automatically register
762 * blk->tfb_tcp_block_name as a stack name. Therefore, you should
763 * explicitly include blk->tfb_tcp_block_name in the list of names if
764 * you wish to register the stack with that name.)
765 *
766 * Either all name registrations will succeed or all will fail. If
767 * a name registration fails, the function will update the num_names
768 * argument to point to the array index of the name that encountered
769 * the failure.
770 *
771 * Returns 0 on success, or an error code on failure.
772 */
773 int
774 register_tcp_functions_as_names(struct tcp_function_block *blk, int wait,
775 const char *names[], int *num_names)
776 {
777 struct tcp_function *n;
778 struct tcp_function_set fs;
779 int error, i;
780
781 KASSERT(names != NULL && *num_names > 0,
782 ("%s: Called with 0-length name list", __func__));
783 KASSERT(names != NULL, ("%s: Called with NULL name list", __func__));
784
785 if (t_functions_inited == 0) {
786 init_tcp_functions();
787 }
788 if ((blk->tfb_tcp_output == NULL) ||
789 (blk->tfb_tcp_do_segment == NULL) ||
790 (blk->tfb_tcp_ctloutput == NULL) ||
791 (strlen(blk->tfb_tcp_block_name) == 0)) {
792 /*
793 * These functions are required and you
794 * need a name.
795 */
796 *num_names = 0;
797 return (EINVAL);
798 }
799 if (blk->tfb_tcp_timer_stop_all ||
800 blk->tfb_tcp_timer_activate ||
801 blk->tfb_tcp_timer_active ||
802 blk->tfb_tcp_timer_stop) {
803 /*
804 * If you define one timer function you
805 * must have them all.
806 */
807 if ((blk->tfb_tcp_timer_stop_all == NULL) ||
808 (blk->tfb_tcp_timer_activate == NULL) ||
809 (blk->tfb_tcp_timer_active == NULL) ||
810 (blk->tfb_tcp_timer_stop == NULL)) {
811 *num_names = 0;
812 return (EINVAL);
813 }
814 }
815
816 refcount_init(&blk->tfb_refcnt, 0);
817 blk->tfb_flags = 0;
818 blk->tfb_id = atomic_fetchadd_int(&next_tcp_stack_id, 1);
819 for (i = 0; i < *num_names; i++) {
820 n = malloc(sizeof(struct tcp_function), M_TCPFUNCTIONS, wait);
821 if (n == NULL) {
822 error = ENOMEM;
823 goto cleanup;
824 }
825 n->tf_fb = blk;
826
827 (void)strncpy(fs.function_set_name, names[i],
828 TCP_FUNCTION_NAME_LEN_MAX);
829 fs.function_set_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
830 rw_wlock(&tcp_function_lock);
831 if (find_tcp_functions_locked(&fs) != NULL) {
832 /* Duplicate name space not allowed */
833 rw_wunlock(&tcp_function_lock);
834 free(n, M_TCPFUNCTIONS);
835 error = EALREADY;
836 goto cleanup;
837 }
838 (void)strncpy(n->tf_name, names[i], TCP_FUNCTION_NAME_LEN_MAX);
839 n->tf_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
840 TAILQ_INSERT_TAIL(&t_functions, n, tf_next);
841 tcp_fb_cnt++;
842 rw_wunlock(&tcp_function_lock);
843 }
844 return(0);
845
846 cleanup:
847 /*
848 * Deregister the names we just added. Because registration failed
849 * for names[i], we don't need to deregister that name.
850 */
851 *num_names = i;
852 rw_wlock(&tcp_function_lock);
853 while (--i >= 0) {
854 TAILQ_FOREACH(n, &t_functions, tf_next) {
855 if (!strncmp(n->tf_name, names[i],
856 TCP_FUNCTION_NAME_LEN_MAX)) {
857 TAILQ_REMOVE(&t_functions, n, tf_next);
858 tcp_fb_cnt--;
859 n->tf_fb = NULL;
860 free(n, M_TCPFUNCTIONS);
861 break;
862 }
863 }
864 }
865 rw_wunlock(&tcp_function_lock);
866 return (error);
867 }
868
869 /*
870 * Register a TCP function block using the name provided in the name
871 * argument.
872 *
873 * Returns 0 on success, or an error code on failure.
874 */
875 int
876 register_tcp_functions_as_name(struct tcp_function_block *blk, const char *name,
877 int wait)
878 {
879 const char *name_list[1];
880 int num_names, rv;
881
882 num_names = 1;
883 if (name != NULL)
884 name_list[0] = name;
885 else
886 name_list[0] = blk->tfb_tcp_block_name;
887 rv = register_tcp_functions_as_names(blk, wait, name_list, &num_names);
888 return (rv);
889 }
890
891 /*
892 * Register a TCP function block using the name defined in
893 * blk->tfb_tcp_block_name.
894 *
895 * Returns 0 on success, or an error code on failure.
896 */
897 int
898 register_tcp_functions(struct tcp_function_block *blk, int wait)
899 {
900
901 return (register_tcp_functions_as_name(blk, NULL, wait));
902 }
903
904 /*
905 * Deregister all names associated with a function block. This
906 * functionally removes the function block from use within the system.
907 *
908 * When called with a true quiesce argument, mark the function block
909 * as being removed so no more stacks will use it and determine
910 * whether the removal would succeed.
911 *
912 * When called with a false quiesce argument, actually attempt the
913 * removal.
914 *
915 * When called with a force argument, attempt to switch all TCBs to
916 * use the default stack instead of returning EBUSY.
917 *
918 * Returns 0 on success (or if the removal would succeed, or an error
919 * code on failure.
920 */
921 int
922 deregister_tcp_functions(struct tcp_function_block *blk, bool quiesce,
923 bool force)
924 {
925 struct tcp_function *f;
926
927 if (strcmp(blk->tfb_tcp_block_name, "default") == 0) {
928 /* You can't un-register the default */
929 return (EPERM);
930 }
931 rw_wlock(&tcp_function_lock);
932 if (blk == tcp_func_set_ptr) {
933 /* You can't free the current default */
934 rw_wunlock(&tcp_function_lock);
935 return (EBUSY);
936 }
937 /* Mark the block so no more stacks can use it. */
938 blk->tfb_flags |= TCP_FUNC_BEING_REMOVED;
939 /*
940 * If TCBs are still attached to the stack, attempt to switch them
941 * to the default stack.
942 */
943 if (force && blk->tfb_refcnt) {
944 struct inpcb *inp;
945 struct tcpcb *tp;
946 VNET_ITERATOR_DECL(vnet_iter);
947
948 rw_wunlock(&tcp_function_lock);
949
950 VNET_LIST_RLOCK();
951 VNET_FOREACH(vnet_iter) {
952 CURVNET_SET(vnet_iter);
953 INP_INFO_WLOCK(&V_tcbinfo);
954 CK_LIST_FOREACH(inp, V_tcbinfo.ipi_listhead, inp_list) {
955 INP_WLOCK(inp);
956 if (inp->inp_flags & INP_TIMEWAIT) {
957 INP_WUNLOCK(inp);
958 continue;
959 }
960 tp = intotcpcb(inp);
961 if (tp == NULL || tp->t_fb != blk) {
962 INP_WUNLOCK(inp);
963 continue;
964 }
965 tcp_switch_back_to_default(tp);
966 INP_WUNLOCK(inp);
967 }
968 INP_INFO_WUNLOCK(&V_tcbinfo);
969 CURVNET_RESTORE();
970 }
971 VNET_LIST_RUNLOCK();
972
973 rw_wlock(&tcp_function_lock);
974 }
975 if (blk->tfb_refcnt) {
976 /* TCBs still attached. */
977 rw_wunlock(&tcp_function_lock);
978 return (EBUSY);
979 }
980 if (quiesce) {
981 /* Skip removal. */
982 rw_wunlock(&tcp_function_lock);
983 return (0);
984 }
985 /* Remove any function names that map to this function block. */
986 while (find_tcp_fb_locked(blk, &f) != NULL) {
987 TAILQ_REMOVE(&t_functions, f, tf_next);
988 tcp_fb_cnt--;
989 f->tf_fb = NULL;
990 free(f, M_TCPFUNCTIONS);
991 }
992 rw_wunlock(&tcp_function_lock);
993 return (0);
994 }
995
996 void
997 tcp_init(void)
998 {
999 const char *tcbhash_tuneable;
1000 int hashsize;
1001
1002 tcbhash_tuneable = "net.inet.tcp.tcbhashsize";
1003
1004 #ifdef TCP_HHOOK
1005 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN,
1006 &V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
1007 printf("%s: WARNING: unable to register helper hook\n", __func__);
1008 if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT,
1009 &V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
1010 printf("%s: WARNING: unable to register helper hook\n", __func__);
1011 #endif
1012 hashsize = TCBHASHSIZE;
1013 TUNABLE_INT_FETCH(tcbhash_tuneable, &hashsize);
1014 if (hashsize == 0) {
1015 /*
1016 * Auto tune the hash size based on maxsockets.
1017 * A perfect hash would have a 1:1 mapping
1018 * (hashsize = maxsockets) however it's been
1019 * suggested that O(2) average is better.
1020 */
1021 hashsize = maketcp_hashsize(maxsockets / 4);
1022 /*
1023 * Our historical default is 512,
1024 * do not autotune lower than this.
1025 */
1026 if (hashsize < 512)
1027 hashsize = 512;
1028 if (bootverbose && IS_DEFAULT_VNET(curvnet))
1029 printf("%s: %s auto tuned to %d\n", __func__,
1030 tcbhash_tuneable, hashsize);
1031 }
1032 /*
1033 * We require a hashsize to be a power of two.
1034 * Previously if it was not a power of two we would just reset it
1035 * back to 512, which could be a nasty surprise if you did not notice
1036 * the error message.
1037 * Instead what we do is clip it to the closest power of two lower
1038 * than the specified hash value.
1039 */
1040 if (!powerof2(hashsize)) {
1041 int oldhashsize = hashsize;
1042
1043 hashsize = maketcp_hashsize(hashsize);
1044 /* prevent absurdly low value */
1045 if (hashsize < 16)
1046 hashsize = 16;
1047 printf("%s: WARNING: TCB hash size not a power of 2, "
1048 "clipped from %d to %d.\n", __func__, oldhashsize,
1049 hashsize);
1050 }
1051 in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize,
1052 "tcp_inpcb", tcp_inpcb_init, IPI_HASHFIELDS_4TUPLE);
1053
1054 /*
1055 * These have to be type stable for the benefit of the timers.
1056 */
1057 V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
1058 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
1059 uma_zone_set_max(V_tcpcb_zone, maxsockets);
1060 uma_zone_set_warning(V_tcpcb_zone, "kern.ipc.maxsockets limit reached");
1061
1062 tcp_tw_init();
1063 syncache_init();
1064 tcp_hc_init();
1065
1066 TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
1067 V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
1068 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
1069
1070 tcp_fastopen_init();
1071
1072 /* Skip initialization of globals for non-default instances. */
1073 if (!IS_DEFAULT_VNET(curvnet))
1074 return;
1075
1076 tcp_reass_global_init();
1077
1078 /* XXX virtualize those bellow? */
1079 tcp_delacktime = TCPTV_DELACK;
1080 tcp_keepinit = TCPTV_KEEP_INIT;
1081 tcp_keepidle = TCPTV_KEEP_IDLE;
1082 tcp_keepintvl = TCPTV_KEEPINTVL;
1083 tcp_maxpersistidle = TCPTV_KEEP_IDLE;
1084 tcp_msl = TCPTV_MSL;
1085 tcp_rexmit_min = TCPTV_MIN;
1086 if (tcp_rexmit_min < 1)
1087 tcp_rexmit_min = 1;
1088 tcp_persmin = TCPTV_PERSMIN;
1089 tcp_persmax = TCPTV_PERSMAX;
1090 tcp_rexmit_slop = TCPTV_CPU_VAR;
1091 tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
1092 tcp_tcbhashsize = hashsize;
1093 /* Setup the tcp function block list */
1094 init_tcp_functions();
1095 register_tcp_functions(&tcp_def_funcblk, M_WAITOK);
1096 #ifdef TCP_BLACKBOX
1097 /* Initialize the TCP logging data. */
1098 tcp_log_init();
1099 #endif
1100 arc4rand(&V_ts_offset_secret, sizeof(V_ts_offset_secret), 0);
1101
1102 if (tcp_soreceive_stream) {
1103 #ifdef INET
1104 tcp_usrreqs.pru_soreceive = soreceive_stream;
1105 #endif
1106 #ifdef INET6
1107 tcp6_usrreqs.pru_soreceive = soreceive_stream;
1108 #endif /* INET6 */
1109 }
1110
1111 #ifdef INET6
1112 #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
1113 #else /* INET6 */
1114 #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
1115 #endif /* INET6 */
1116 if (max_protohdr < TCP_MINPROTOHDR)
1117 max_protohdr = TCP_MINPROTOHDR;
1118 if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
1119 panic("tcp_init");
1120 #undef TCP_MINPROTOHDR
1121
1122 ISN_LOCK_INIT();
1123 EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
1124 SHUTDOWN_PRI_DEFAULT);
1125 EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL,
1126 EVENTHANDLER_PRI_ANY);
1127 #ifdef TCPPCAP
1128 tcp_pcap_init();
1129 #endif
1130 }
1131
1132 #ifdef VIMAGE
1133 static void
1134 tcp_destroy(void *unused __unused)
1135 {
1136 int n;
1137 #ifdef TCP_HHOOK
1138 int error;
1139 #endif
1140
1141 /*
1142 * All our processes are gone, all our sockets should be cleaned
1143 * up, which means, we should be past the tcp_discardcb() calls.
1144 * Sleep to let all tcpcb timers really disappear and cleanup.
1145 */
1146 for (;;) {
1147 INP_LIST_RLOCK(&V_tcbinfo);
1148 n = V_tcbinfo.ipi_count;
1149 INP_LIST_RUNLOCK(&V_tcbinfo);
1150 if (n == 0)
1151 break;
1152 pause("tcpdes", hz / 10);
1153 }
1154 tcp_hc_destroy();
1155 syncache_destroy();
1156 tcp_tw_destroy();
1157 in_pcbinfo_destroy(&V_tcbinfo);
1158 /* tcp_discardcb() clears the sack_holes up. */
1159 uma_zdestroy(V_sack_hole_zone);
1160 uma_zdestroy(V_tcpcb_zone);
1161
1162 /*
1163 * Cannot free the zone until all tcpcbs are released as we attach
1164 * the allocations to them.
1165 */
1166 tcp_fastopen_destroy();
1167
1168 #ifdef TCP_HHOOK
1169 error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_IN]);
1170 if (error != 0) {
1171 printf("%s: WARNING: unable to deregister helper hook "
1172 "type=%d, id=%d: error %d returned\n", __func__,
1173 HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN, error);
1174 }
1175 error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_OUT]);
1176 if (error != 0) {
1177 printf("%s: WARNING: unable to deregister helper hook "
1178 "type=%d, id=%d: error %d returned\n", __func__,
1179 HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT, error);
1180 }
1181 #endif
1182 }
1183 VNET_SYSUNINIT(tcp, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH, tcp_destroy, NULL);
1184 #endif
1185
1186 void
1187 tcp_fini(void *xtp)
1188 {
1189
1190 }
1191
1192 /*
1193 * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
1194 * tcp_template used to store this data in mbufs, but we now recopy it out
1195 * of the tcpcb each time to conserve mbufs.
1196 */
1197 void
1198 tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr)
1199 {
1200 struct tcphdr *th = (struct tcphdr *)tcp_ptr;
1201
1202 INP_WLOCK_ASSERT(inp);
1203
1204 #ifdef INET6
1205 if ((inp->inp_vflag & INP_IPV6) != 0) {
1206 struct ip6_hdr *ip6;
1207
1208 ip6 = (struct ip6_hdr *)ip_ptr;
1209 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
1210 (inp->inp_flow & IPV6_FLOWINFO_MASK);
1211 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
1212 (IPV6_VERSION & IPV6_VERSION_MASK);
1213 ip6->ip6_nxt = IPPROTO_TCP;
1214 ip6->ip6_plen = htons(sizeof(struct tcphdr));
1215 ip6->ip6_src = inp->in6p_laddr;
1216 ip6->ip6_dst = inp->in6p_faddr;
1217 }
1218 #endif /* INET6 */
1219 #if defined(INET6) && defined(INET)
1220 else
1221 #endif
1222 #ifdef INET
1223 {
1224 struct ip *ip;
1225
1226 ip = (struct ip *)ip_ptr;
1227 ip->ip_v = IPVERSION;
1228 ip->ip_hl = 5;
1229 ip->ip_tos = inp->inp_ip_tos;
1230 ip->ip_len = 0;
1231 ip->ip_id = 0;
1232 ip->ip_off = 0;
1233 ip->ip_ttl = inp->inp_ip_ttl;
1234 ip->ip_sum = 0;
1235 ip->ip_p = IPPROTO_TCP;
1236 ip->ip_src = inp->inp_laddr;
1237 ip->ip_dst = inp->inp_faddr;
1238 }
1239 #endif /* INET */
1240 th->th_sport = inp->inp_lport;
1241 th->th_dport = inp->inp_fport;
1242 th->th_seq = 0;
1243 th->th_ack = 0;
1244 th->th_x2 = 0;
1245 th->th_off = 5;
1246 th->th_flags = 0;
1247 th->th_win = 0;
1248 th->th_urp = 0;
1249 th->th_sum = 0; /* in_pseudo() is called later for ipv4 */
1250 }
1251
1252 /*
1253 * Create template to be used to send tcp packets on a connection.
1254 * Allocates an mbuf and fills in a skeletal tcp/ip header. The only
1255 * use for this function is in keepalives, which use tcp_respond.
1256 */
1257 struct tcptemp *
1258 tcpip_maketemplate(struct inpcb *inp)
1259 {
1260 struct tcptemp *t;
1261
1262 t = malloc(sizeof(*t), M_TEMP, M_NOWAIT);
1263 if (t == NULL)
1264 return (NULL);
1265 tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t);
1266 return (t);
1267 }
1268
1269 /*
1270 * Send a single message to the TCP at address specified by
1271 * the given TCP/IP header. If m == NULL, then we make a copy
1272 * of the tcpiphdr at th and send directly to the addressed host.
1273 * This is used to force keep alive messages out using the TCP
1274 * template for a connection. If flags are given then we send
1275 * a message back to the TCP which originated the segment th,
1276 * and discard the mbuf containing it and any other attached mbufs.
1277 *
1278 * In any case the ack and sequence number of the transmitted
1279 * segment are as specified by the parameters.
1280 *
1281 * NOTE: If m != NULL, then th must point to *inside* the mbuf.
1282 */
1283 void
1284 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
1285 tcp_seq ack, tcp_seq seq, int flags)
1286 {
1287 struct tcpopt to;
1288 struct inpcb *inp;
1289 struct ip *ip;
1290 struct mbuf *optm;
1291 struct tcphdr *nth;
1292 u_char *optp;
1293 #ifdef INET6
1294 struct ip6_hdr *ip6;
1295 int isipv6;
1296 #endif /* INET6 */
1297 int optlen, tlen, win;
1298 bool incl_opts;
1299
1300 KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
1301
1302 #ifdef INET6
1303 isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4);
1304 ip6 = ipgen;
1305 #endif /* INET6 */
1306 ip = ipgen;
1307
1308 if (tp != NULL) {
1309 inp = tp->t_inpcb;
1310 KASSERT(inp != NULL, ("tcp control block w/o inpcb"));
1311 INP_WLOCK_ASSERT(inp);
1312 } else
1313 inp = NULL;
1314
1315 incl_opts = false;
1316 win = 0;
1317 if (tp != NULL) {
1318 if (!(flags & TH_RST)) {
1319 win = sbspace(&inp->inp_socket->so_rcv);
1320 if (win > TCP_MAXWIN << tp->rcv_scale)
1321 win = TCP_MAXWIN << tp->rcv_scale;
1322 }
1323 if ((tp->t_flags & TF_NOOPT) == 0)
1324 incl_opts = true;
1325 }
1326 if (m == NULL) {
1327 m = m_gethdr(M_NOWAIT, MT_DATA);
1328 if (m == NULL)
1329 return;
1330 m->m_data += max_linkhdr;
1331 #ifdef INET6
1332 if (isipv6) {
1333 bcopy((caddr_t)ip6, mtod(m, caddr_t),
1334 sizeof(struct ip6_hdr));
1335 ip6 = mtod(m, struct ip6_hdr *);
1336 nth = (struct tcphdr *)(ip6 + 1);
1337 } else
1338 #endif /* INET6 */
1339 {
1340 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
1341 ip = mtod(m, struct ip *);
1342 nth = (struct tcphdr *)(ip + 1);
1343 }
1344 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
1345 flags = TH_ACK;
1346 } else if (!M_WRITABLE(m)) {
1347 struct mbuf *n;
1348
1349 /* Can't reuse 'm', allocate a new mbuf. */
1350 n = m_gethdr(M_NOWAIT, MT_DATA);
1351 if (n == NULL) {
1352 m_freem(m);
1353 return;
1354 }
1355
1356 if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
1357 m_freem(m);
1358 m_freem(n);
1359 return;
1360 }
1361
1362 n->m_data += max_linkhdr;
1363 /* m_len is set later */
1364 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
1365 #ifdef INET6
1366 if (isipv6) {
1367 bcopy((caddr_t)ip6, mtod(n, caddr_t),
1368 sizeof(struct ip6_hdr));
1369 ip6 = mtod(n, struct ip6_hdr *);
1370 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
1371 nth = (struct tcphdr *)(ip6 + 1);
1372 } else
1373 #endif /* INET6 */
1374 {
1375 bcopy((caddr_t)ip, mtod(n, caddr_t), sizeof(struct ip));
1376 ip = mtod(n, struct ip *);
1377 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
1378 nth = (struct tcphdr *)(ip + 1);
1379 }
1380 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
1381 xchg(nth->th_dport, nth->th_sport, uint16_t);
1382 th = nth;
1383 m_freem(m);
1384 m = n;
1385 } else {
1386 /*
1387 * reuse the mbuf.
1388 * XXX MRT We inherit the FIB, which is lucky.
1389 */
1390 m_freem(m->m_next);
1391 m->m_next = NULL;
1392 m->m_data = (caddr_t)ipgen;
1393 /* m_len is set later */
1394 #ifdef INET6
1395 if (isipv6) {
1396 xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
1397 nth = (struct tcphdr *)(ip6 + 1);
1398 } else
1399 #endif /* INET6 */
1400 {
1401 xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
1402 nth = (struct tcphdr *)(ip + 1);
1403 }
1404 if (th != nth) {
1405 /*
1406 * this is usually a case when an extension header
1407 * exists between the IPv6 header and the
1408 * TCP header.
1409 */
1410 nth->th_sport = th->th_sport;
1411 nth->th_dport = th->th_dport;
1412 }
1413 xchg(nth->th_dport, nth->th_sport, uint16_t);
1414 #undef xchg
1415 }
1416 tlen = 0;
1417 #ifdef INET6
1418 if (isipv6)
1419 tlen = sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
1420 #endif
1421 #if defined(INET) && defined(INET6)
1422 else
1423 #endif
1424 #ifdef INET
1425 tlen = sizeof (struct tcpiphdr);
1426 #endif
1427 #ifdef INVARIANTS
1428 m->m_len = 0;
1429 KASSERT(M_TRAILINGSPACE(m) >= tlen,
1430 ("Not enough trailing space for message (m=%p, need=%d, have=%ld)",
1431 m, tlen, (long)M_TRAILINGSPACE(m)));
1432 #endif
1433 m->m_len = tlen;
1434 to.to_flags = 0;
1435 if (incl_opts) {
1436 /* Make sure we have room. */
1437 if (M_TRAILINGSPACE(m) < TCP_MAXOLEN) {
1438 m->m_next = m_get(M_NOWAIT, MT_DATA);
1439 if (m->m_next) {
1440 optp = mtod(m->m_next, u_char *);
1441 optm = m->m_next;
1442 } else
1443 incl_opts = false;
1444 } else {
1445 optp = (u_char *) (nth + 1);
1446 optm = m;
1447 }
1448 }
1449 if (incl_opts) {
1450 /* Timestamps. */
1451 if (tp->t_flags & TF_RCVD_TSTMP) {
1452 to.to_tsval = tcp_ts_getticks() + tp->ts_offset;
1453 to.to_tsecr = tp->ts_recent;
1454 to.to_flags |= TOF_TS;
1455 }
1456 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
1457 /* TCP-MD5 (RFC2385). */
1458 if (tp->t_flags & TF_SIGNATURE)
1459 to.to_flags |= TOF_SIGNATURE;
1460 #endif
1461 /* Add the options. */
1462 tlen += optlen = tcp_addoptions(&to, optp);
1463
1464 /* Update m_len in the correct mbuf. */
1465 optm->m_len += optlen;
1466 } else
1467 optlen = 0;
1468 #ifdef INET6
1469 if (isipv6) {
1470 ip6->ip6_flow = 0;
1471 ip6->ip6_vfc = IPV6_VERSION;
1472 ip6->ip6_nxt = IPPROTO_TCP;
1473 ip6->ip6_plen = htons(tlen - sizeof(*ip6));
1474 }
1475 #endif
1476 #if defined(INET) && defined(INET6)
1477 else
1478 #endif
1479 #ifdef INET
1480 {
1481 ip->ip_len = htons(tlen);
1482 ip->ip_ttl = V_ip_defttl;
1483 if (V_path_mtu_discovery)
1484 ip->ip_off |= htons(IP_DF);
1485 }
1486 #endif
1487 m->m_pkthdr.len = tlen;
1488 m->m_pkthdr.rcvif = NULL;
1489 #ifdef MAC
1490 if (inp != NULL) {
1491 /*
1492 * Packet is associated with a socket, so allow the
1493 * label of the response to reflect the socket label.
1494 */
1495 INP_WLOCK_ASSERT(inp);
1496 mac_inpcb_create_mbuf(inp, m);
1497 } else {
1498 /*
1499 * Packet is not associated with a socket, so possibly
1500 * update the label in place.
1501 */
1502 mac_netinet_tcp_reply(m);
1503 }
1504 #endif
1505 nth->th_seq = htonl(seq);
1506 nth->th_ack = htonl(ack);
1507 nth->th_x2 = 0;
1508 nth->th_off = (sizeof (struct tcphdr) + optlen) >> 2;
1509 nth->th_flags = flags;
1510 if (tp != NULL)
1511 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
1512 else
1513 nth->th_win = htons((u_short)win);
1514 nth->th_urp = 0;
1515
1516 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
1517 if (to.to_flags & TOF_SIGNATURE) {
1518 if (!TCPMD5_ENABLED() ||
1519 TCPMD5_OUTPUT(m, nth, to.to_signature) != 0) {
1520 m_freem(m);
1521 return;
1522 }
1523 }
1524 #endif
1525
1526 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
1527 #ifdef INET6
1528 if (isipv6) {
1529 m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
1530 nth->th_sum = in6_cksum_pseudo(ip6,
1531 tlen - sizeof(struct ip6_hdr), IPPROTO_TCP, 0);
1532 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb :
1533 NULL, NULL);
1534 }
1535 #endif /* INET6 */
1536 #if defined(INET6) && defined(INET)
1537 else
1538 #endif
1539 #ifdef INET
1540 {
1541 m->m_pkthdr.csum_flags = CSUM_TCP;
1542 nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
1543 htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
1544 }
1545 #endif /* INET */
1546 #ifdef TCPDEBUG
1547 if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
1548 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
1549 #endif
1550 TCP_PROBE3(debug__output, tp, th, m);
1551 if (flags & TH_RST)
1552 TCP_PROBE5(accept__refused, NULL, NULL, m, tp, nth);
1553
1554 #ifdef INET6
1555 if (isipv6) {
1556 TCP_PROBE5(send, NULL, tp, ip6, tp, nth);
1557 (void)ip6_output(m, NULL, NULL, 0, NULL, NULL, inp);
1558 }
1559 #endif /* INET6 */
1560 #if defined(INET) && defined(INET6)
1561 else
1562 #endif
1563 #ifdef INET
1564 {
1565 TCP_PROBE5(send, NULL, tp, ip, tp, nth);
1566 (void)ip_output(m, NULL, NULL, 0, NULL, inp);
1567 }
1568 #endif
1569 }
1570
1571 /*
1572 * Create a new TCP control block, making an
1573 * empty reassembly queue and hooking it to the argument
1574 * protocol control block. The `inp' parameter must have
1575 * come from the zone allocator set up in tcp_init().
1576 */
1577 struct tcpcb *
1578 tcp_newtcpcb(struct inpcb *inp)
1579 {
1580 struct tcpcb_mem *tm;
1581 struct tcpcb *tp;
1582 #ifdef INET6
1583 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
1584 #endif /* INET6 */
1585
1586 tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO);
1587 if (tm == NULL)
1588 return (NULL);
1589 tp = &tm->tcb;
1590
1591 /* Initialise cc_var struct for this tcpcb. */
1592 tp->ccv = &tm->ccv;
1593 tp->ccv->type = IPPROTO_TCP;
1594 tp->ccv->ccvc.tcp = tp;
1595 rw_rlock(&tcp_function_lock);
1596 tp->t_fb = tcp_func_set_ptr;
1597 refcount_acquire(&tp->t_fb->tfb_refcnt);
1598 rw_runlock(&tcp_function_lock);
1599 /*
1600 * Use the current system default CC algorithm.
1601 */
1602 CC_LIST_RLOCK();
1603 KASSERT(!STAILQ_EMPTY(&cc_list), ("cc_list is empty!"));
1604 CC_ALGO(tp) = CC_DEFAULT();
1605 CC_LIST_RUNLOCK();
1606
1607 if (CC_ALGO(tp)->cb_init != NULL)
1608 if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) {
1609 if (tp->t_fb->tfb_tcp_fb_fini)
1610 (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
1611 refcount_release(&tp->t_fb->tfb_refcnt);
1612 uma_zfree(V_tcpcb_zone, tm);
1613 return (NULL);
1614 }
1615
1616 #ifdef TCP_HHOOK
1617 tp->osd = &tm->osd;
1618 if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) {
1619 if (tp->t_fb->tfb_tcp_fb_fini)
1620 (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
1621 refcount_release(&tp->t_fb->tfb_refcnt);
1622 uma_zfree(V_tcpcb_zone, tm);
1623 return (NULL);
1624 }
1625 #endif
1626
1627 #ifdef VIMAGE
1628 tp->t_vnet = inp->inp_vnet;
1629 #endif
1630 tp->t_timers = &tm->tt;
1631 TAILQ_INIT(&tp->t_segq);
1632 tp->t_maxseg =
1633 #ifdef INET6
1634 isipv6 ? V_tcp_v6mssdflt :
1635 #endif /* INET6 */
1636 V_tcp_mssdflt;
1637
1638 /* Set up our timeouts. */
1639 callout_init(&tp->t_timers->tt_rexmt, 1);
1640 callout_init(&tp->t_timers->tt_persist, 1);
1641 callout_init(&tp->t_timers->tt_keep, 1);
1642 callout_init(&tp->t_timers->tt_2msl, 1);
1643 callout_init(&tp->t_timers->tt_delack, 1);
1644
1645 if (V_tcp_do_rfc1323)
1646 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
1647 if (V_tcp_do_sack)
1648 tp->t_flags |= TF_SACK_PERMIT;
1649 TAILQ_INIT(&tp->snd_holes);
1650 /*
1651 * The tcpcb will hold a reference on its inpcb until tcp_discardcb()
1652 * is called.
1653 */
1654 in_pcbref(inp); /* Reference for tcpcb */
1655 tp->t_inpcb = inp;
1656
1657 /*
1658 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
1659 * rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
1660 * reasonable initial retransmit time.
1661 */
1662 tp->t_srtt = TCPTV_SRTTBASE;
1663 tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
1664 tp->t_rttmin = tcp_rexmit_min;
1665 tp->t_rxtcur = TCPTV_RTOBASE;
1666 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1667 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
1668 tp->t_rcvtime = ticks;
1669 /*
1670 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
1671 * because the socket may be bound to an IPv6 wildcard address,
1672 * which may match an IPv4-mapped IPv6 address.
1673 */
1674 inp->inp_ip_ttl = V_ip_defttl;
1675 inp->inp_ppcb = tp;
1676 #ifdef TCPPCAP
1677 /*
1678 * Init the TCP PCAP queues.
1679 */
1680 tcp_pcap_tcpcb_init(tp);
1681 #endif
1682 #ifdef TCP_BLACKBOX
1683 /* Initialize the per-TCPCB log data. */
1684 tcp_log_tcpcbinit(tp);
1685 #endif
1686 if (tp->t_fb->tfb_tcp_fb_init) {
1687 (*tp->t_fb->tfb_tcp_fb_init)(tp);
1688 }
1689 return (tp); /* XXX */
1690 }
1691
1692 /*
1693 * Switch the congestion control algorithm back to NewReno for any active
1694 * control blocks using an algorithm which is about to go away.
1695 * This ensures the CC framework can allow the unload to proceed without leaving
1696 * any dangling pointers which would trigger a panic.
1697 * Returning non-zero would inform the CC framework that something went wrong
1698 * and it would be unsafe to allow the unload to proceed. However, there is no
1699 * way for this to occur with this implementation so we always return zero.
1700 */
1701 int
1702 tcp_ccalgounload(struct cc_algo *unload_algo)
1703 {
1704 struct cc_algo *tmpalgo;
1705 struct inpcb *inp;
1706 struct tcpcb *tp;
1707 VNET_ITERATOR_DECL(vnet_iter);
1708
1709 /*
1710 * Check all active control blocks across all network stacks and change
1711 * any that are using "unload_algo" back to NewReno. If "unload_algo"
1712 * requires cleanup code to be run, call it.
1713 */
1714 VNET_LIST_RLOCK();
1715 VNET_FOREACH(vnet_iter) {
1716 CURVNET_SET(vnet_iter);
1717 INP_INFO_WLOCK(&V_tcbinfo);
1718 /*
1719 * New connections already part way through being initialised
1720 * with the CC algo we're removing will not race with this code
1721 * because the INP_INFO_WLOCK is held during initialisation. We
1722 * therefore don't enter the loop below until the connection
1723 * list has stabilised.
1724 */
1725 CK_LIST_FOREACH(inp, &V_tcb, inp_list) {
1726 INP_WLOCK(inp);
1727 /* Important to skip tcptw structs. */
1728 if (!(inp->inp_flags & INP_TIMEWAIT) &&
1729 (tp = intotcpcb(inp)) != NULL) {
1730 /*
1731 * By holding INP_WLOCK here, we are assured
1732 * that the connection is not currently
1733 * executing inside the CC module's functions
1734 * i.e. it is safe to make the switch back to
1735 * NewReno.
1736 */
1737 if (CC_ALGO(tp) == unload_algo) {
1738 tmpalgo = CC_ALGO(tp);
1739 if (tmpalgo->cb_destroy != NULL)
1740 tmpalgo->cb_destroy(tp->ccv);
1741 CC_DATA(tp) = NULL;
1742 /*
1743 * NewReno may allocate memory on
1744 * demand for certain stateful
1745 * configuration as needed, but is
1746 * coded to never fail on memory
1747 * allocation failure so it is a safe
1748 * fallback.
1749 */
1750 CC_ALGO(tp) = &newreno_cc_algo;
1751 }
1752 }
1753 INP_WUNLOCK(inp);
1754 }
1755 INP_INFO_WUNLOCK(&V_tcbinfo);
1756 CURVNET_RESTORE();
1757 }
1758 VNET_LIST_RUNLOCK();
1759
1760 return (0);
1761 }
1762
1763 /*
1764 * Drop a TCP connection, reporting
1765 * the specified error. If connection is synchronized,
1766 * then send a RST to peer.
1767 */
1768 struct tcpcb *
1769 tcp_drop(struct tcpcb *tp, int errno)
1770 {
1771 struct socket *so = tp->t_inpcb->inp_socket;
1772
1773 INP_INFO_LOCK_ASSERT(&V_tcbinfo);
1774 INP_WLOCK_ASSERT(tp->t_inpcb);
1775
1776 if (TCPS_HAVERCVDSYN(tp->t_state)) {
1777 tcp_state_change(tp, TCPS_CLOSED);
1778 (void) tp->t_fb->tfb_tcp_output(tp);
1779 TCPSTAT_INC(tcps_drops);
1780 } else
1781 TCPSTAT_INC(tcps_conndrops);
1782 if (errno == ETIMEDOUT && tp->t_softerror)
1783 errno = tp->t_softerror;
1784 so->so_error = errno;
1785 return (tcp_close(tp));
1786 }
1787
1788 void
1789 tcp_discardcb(struct tcpcb *tp)
1790 {
1791 struct inpcb *inp = tp->t_inpcb;
1792 struct socket *so = inp->inp_socket;
1793 #ifdef INET6
1794 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
1795 #endif /* INET6 */
1796 int released __unused;
1797
1798 INP_WLOCK_ASSERT(inp);
1799
1800 /*
1801 * Make sure that all of our timers are stopped before we delete the
1802 * PCB.
1803 *
1804 * If stopping a timer fails, we schedule a discard function in same
1805 * callout, and the last discard function called will take care of
1806 * deleting the tcpcb.
1807 */
1808 tp->t_timers->tt_draincnt = 0;
1809 tcp_timer_stop(tp, TT_REXMT);
1810 tcp_timer_stop(tp, TT_PERSIST);
1811 tcp_timer_stop(tp, TT_KEEP);
1812 tcp_timer_stop(tp, TT_2MSL);
1813 tcp_timer_stop(tp, TT_DELACK);
1814 if (tp->t_fb->tfb_tcp_timer_stop_all) {
1815 /*
1816 * Call the stop-all function of the methods,
1817 * this function should call the tcp_timer_stop()
1818 * method with each of the function specific timeouts.
1819 * That stop will be called via the tfb_tcp_timer_stop()
1820 * which should use the async drain function of the
1821 * callout system (see tcp_var.h).
1822 */
1823 tp->t_fb->tfb_tcp_timer_stop_all(tp);
1824 }
1825
1826 /*
1827 * If we got enough samples through the srtt filter,
1828 * save the rtt and rttvar in the routing entry.
1829 * 'Enough' is arbitrarily defined as 4 rtt samples.
1830 * 4 samples is enough for the srtt filter to converge
1831 * to within enough % of the correct value; fewer samples
1832 * and we could save a bogus rtt. The danger is not high
1833 * as tcp quickly recovers from everything.
1834 * XXX: Works very well but needs some more statistics!
1835 */
1836 if (tp->t_rttupdated >= 4) {
1837 struct hc_metrics_lite metrics;
1838 uint32_t ssthresh;
1839
1840 bzero(&metrics, sizeof(metrics));
1841 /*
1842 * Update the ssthresh always when the conditions below
1843 * are satisfied. This gives us better new start value
1844 * for the congestion avoidance for new connections.
1845 * ssthresh is only set if packet loss occurred on a session.
1846 *
1847 * XXXRW: 'so' may be NULL here, and/or socket buffer may be
1848 * being torn down. Ideally this code would not use 'so'.
1849 */
1850 ssthresh = tp->snd_ssthresh;
1851 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) {
1852 /*
1853 * convert the limit from user data bytes to
1854 * packets then to packet data bytes.
1855 */
1856 ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg;
1857 if (ssthresh < 2)
1858 ssthresh = 2;
1859 ssthresh *= (tp->t_maxseg +
1860 #ifdef INET6
1861 (isipv6 ? sizeof (struct ip6_hdr) +
1862 sizeof (struct tcphdr) :
1863 #endif
1864 sizeof (struct tcpiphdr)
1865 #ifdef INET6
1866 )
1867 #endif
1868 );
1869 } else
1870 ssthresh = 0;
1871 metrics.rmx_ssthresh = ssthresh;
1872
1873 metrics.rmx_rtt = tp->t_srtt;
1874 metrics.rmx_rttvar = tp->t_rttvar;
1875 metrics.rmx_cwnd = tp->snd_cwnd;
1876 metrics.rmx_sendpipe = 0;
1877 metrics.rmx_recvpipe = 0;
1878
1879 tcp_hc_update(&inp->inp_inc, &metrics);
1880 }
1881
1882 /* free the reassembly queue, if any */
1883 tcp_reass_flush(tp);
1884
1885 #ifdef TCP_OFFLOAD
1886 /* Disconnect offload device, if any. */
1887 if (tp->t_flags & TF_TOE)
1888 tcp_offload_detach(tp);
1889 #endif
1890
1891 tcp_free_sackholes(tp);
1892
1893 #ifdef TCPPCAP
1894 /* Free the TCP PCAP queues. */
1895 tcp_pcap_drain(&(tp->t_inpkts));
1896 tcp_pcap_drain(&(tp->t_outpkts));
1897 #endif
1898
1899 /* Allow the CC algorithm to clean up after itself. */
1900 if (CC_ALGO(tp)->cb_destroy != NULL)
1901 CC_ALGO(tp)->cb_destroy(tp->ccv);
1902 CC_DATA(tp) = NULL;
1903
1904 #ifdef TCP_HHOOK
1905 khelp_destroy_osd(tp->osd);
1906 #endif
1907
1908 CC_ALGO(tp) = NULL;
1909 inp->inp_ppcb = NULL;
1910 if (tp->t_timers->tt_draincnt == 0) {
1911 /* We own the last reference on tcpcb, let's free it. */
1912 #ifdef TCP_BLACKBOX
1913 tcp_log_tcpcbfini(tp);
1914 #endif
1915 TCPSTATES_DEC(tp->t_state);
1916 if (tp->t_fb->tfb_tcp_fb_fini)
1917 (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
1918 refcount_release(&tp->t_fb->tfb_refcnt);
1919 tp->t_inpcb = NULL;
1920 uma_zfree(V_tcpcb_zone, tp);
1921 released = in_pcbrele_wlocked(inp);
1922 KASSERT(!released, ("%s: inp %p should not have been released "
1923 "here", __func__, inp));
1924 }
1925 }
1926
1927 void
1928 tcp_timer_discard(void *ptp)
1929 {
1930 struct inpcb *inp;
1931 struct tcpcb *tp;
1932 struct epoch_tracker et;
1933
1934 tp = (struct tcpcb *)ptp;
1935 CURVNET_SET(tp->t_vnet);
1936 INP_INFO_RLOCK_ET(&V_tcbinfo, et);
1937 inp = tp->t_inpcb;
1938 KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL",
1939 __func__, tp));
1940 INP_WLOCK(inp);
1941 KASSERT((tp->t_timers->tt_flags & TT_STOPPED) != 0,
1942 ("%s: tcpcb has to be stopped here", __func__));
1943 tp->t_timers->tt_draincnt--;
1944 if (tp->t_timers->tt_draincnt == 0) {
1945 /* We own the last reference on this tcpcb, let's free it. */
1946 #ifdef TCP_BLACKBOX
1947 tcp_log_tcpcbfini(tp);
1948 #endif
1949 TCPSTATES_DEC(tp->t_state);
1950 if (tp->t_fb->tfb_tcp_fb_fini)
1951 (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
1952 refcount_release(&tp->t_fb->tfb_refcnt);
1953 tp->t_inpcb = NULL;
1954 uma_zfree(V_tcpcb_zone, tp);
1955 if (in_pcbrele_wlocked(inp)) {
1956 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
1957 CURVNET_RESTORE();
1958 return;
1959 }
1960 }
1961 INP_WUNLOCK(inp);
1962 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
1963 CURVNET_RESTORE();
1964 }
1965
1966 /*
1967 * Attempt to close a TCP control block, marking it as dropped, and freeing
1968 * the socket if we hold the only reference.
1969 */
1970 struct tcpcb *
1971 tcp_close(struct tcpcb *tp)
1972 {
1973 struct inpcb *inp = tp->t_inpcb;
1974 struct socket *so;
1975
1976 INP_INFO_LOCK_ASSERT(&V_tcbinfo);
1977 INP_WLOCK_ASSERT(inp);
1978
1979 #ifdef TCP_OFFLOAD
1980 if (tp->t_state == TCPS_LISTEN)
1981 tcp_offload_listen_stop(tp);
1982 #endif
1983 /*
1984 * This releases the TFO pending counter resource for TFO listen
1985 * sockets as well as passively-created TFO sockets that transition
1986 * from SYN_RECEIVED to CLOSED.
1987 */
1988 if (tp->t_tfo_pending) {
1989 tcp_fastopen_decrement_counter(tp->t_tfo_pending);
1990 tp->t_tfo_pending = NULL;
1991 }
1992 in_pcbdrop(inp);
1993 TCPSTAT_INC(tcps_closed);
1994 if (tp->t_state != TCPS_CLOSED)
1995 tcp_state_change(tp, TCPS_CLOSED);
1996 KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
1997 so = inp->inp_socket;
1998 soisdisconnected(so);
1999 if (inp->inp_flags & INP_SOCKREF) {
2000 KASSERT(so->so_state & SS_PROTOREF,
2001 ("tcp_close: !SS_PROTOREF"));
2002 inp->inp_flags &= ~INP_SOCKREF;
2003 INP_WUNLOCK(inp);
2004 SOCK_LOCK(so);
2005 so->so_state &= ~SS_PROTOREF;
2006 sofree(so);
2007 return (NULL);
2008 }
2009 return (tp);
2010 }
2011
2012 void
2013 tcp_drain(void)
2014 {
2015 VNET_ITERATOR_DECL(vnet_iter);
2016
2017 if (!do_tcpdrain)
2018 return;
2019
2020 VNET_LIST_RLOCK_NOSLEEP();
2021 VNET_FOREACH(vnet_iter) {
2022 CURVNET_SET(vnet_iter);
2023 struct inpcb *inpb;
2024 struct tcpcb *tcpb;
2025
2026 /*
2027 * Walk the tcpbs, if existing, and flush the reassembly queue,
2028 * if there is one...
2029 * XXX: The "Net/3" implementation doesn't imply that the TCP
2030 * reassembly queue should be flushed, but in a situation
2031 * where we're really low on mbufs, this is potentially
2032 * useful.
2033 */
2034 INP_INFO_WLOCK(&V_tcbinfo);
2035 CK_LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) {
2036 INP_WLOCK(inpb);
2037 if (inpb->inp_flags & INP_TIMEWAIT) {
2038 INP_WUNLOCK(inpb);
2039 continue;
2040 }
2041 if ((tcpb = intotcpcb(inpb)) != NULL) {
2042 tcp_reass_flush(tcpb);
2043 tcp_clean_sackreport(tcpb);
2044 #ifdef TCP_BLACKBOX
2045 tcp_log_drain(tcpb);
2046 #endif
2047 #ifdef TCPPCAP
2048 if (tcp_pcap_aggressive_free) {
2049 /* Free the TCP PCAP queues. */
2050 tcp_pcap_drain(&(tcpb->t_inpkts));
2051 tcp_pcap_drain(&(tcpb->t_outpkts));
2052 }
2053 #endif
2054 }
2055 INP_WUNLOCK(inpb);
2056 }
2057 INP_INFO_WUNLOCK(&V_tcbinfo);
2058 CURVNET_RESTORE();
2059 }
2060 VNET_LIST_RUNLOCK_NOSLEEP();
2061 }
2062
2063 /*
2064 * Notify a tcp user of an asynchronous error;
2065 * store error as soft error, but wake up user
2066 * (for now, won't do anything until can select for soft error).
2067 *
2068 * Do not wake up user since there currently is no mechanism for
2069 * reporting soft errors (yet - a kqueue filter may be added).
2070 */
2071 static struct inpcb *
2072 tcp_notify(struct inpcb *inp, int error)
2073 {
2074 struct tcpcb *tp;
2075
2076 INP_INFO_LOCK_ASSERT(&V_tcbinfo);
2077 INP_WLOCK_ASSERT(inp);
2078
2079 if ((inp->inp_flags & INP_TIMEWAIT) ||
2080 (inp->inp_flags & INP_DROPPED))
2081 return (inp);
2082
2083 tp = intotcpcb(inp);
2084 KASSERT(tp != NULL, ("tcp_notify: tp == NULL"));
2085
2086 /*
2087 * Ignore some errors if we are hooked up.
2088 * If connection hasn't completed, has retransmitted several times,
2089 * and receives a second error, give up now. This is better
2090 * than waiting a long time to establish a connection that
2091 * can never complete.
2092 */
2093 if (tp->t_state == TCPS_ESTABLISHED &&
2094 (error == EHOSTUNREACH || error == ENETUNREACH ||
2095 error == EHOSTDOWN)) {
2096 if (inp->inp_route.ro_rt) {
2097 RTFREE(inp->inp_route.ro_rt);
2098 inp->inp_route.ro_rt = (struct rtentry *)NULL;
2099 }
2100 return (inp);
2101 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
2102 tp->t_softerror) {
2103 tp = tcp_drop(tp, error);
2104 if (tp != NULL)
2105 return (inp);
2106 else
2107 return (NULL);
2108 } else {
2109 tp->t_softerror = error;
2110 return (inp);
2111 }
2112 #if 0
2113 wakeup( &so->so_timeo);
2114 sorwakeup(so);
2115 sowwakeup(so);
2116 #endif
2117 }
2118
2119 static int
2120 tcp_pcblist(SYSCTL_HANDLER_ARGS)
2121 {
2122 int error, i, m, n, pcb_count;
2123 struct inpcb *inp, **inp_list;
2124 inp_gen_t gencnt;
2125 struct xinpgen xig;
2126 struct epoch_tracker et;
2127
2128 /*
2129 * The process of preparing the TCB list is too time-consuming and
2130 * resource-intensive to repeat twice on every request.
2131 */
2132 if (req->oldptr == NULL) {
2133 n = V_tcbinfo.ipi_count +
2134 counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
2135 n += imax(n / 8, 10);
2136 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
2137 return (0);
2138 }
2139
2140 if (req->newptr != NULL)
2141 return (EPERM);
2142
2143 /*
2144 * OK, now we're committed to doing something.
2145 */
2146 INP_LIST_RLOCK(&V_tcbinfo);
2147 gencnt = V_tcbinfo.ipi_gencnt;
2148 n = V_tcbinfo.ipi_count;
2149 INP_LIST_RUNLOCK(&V_tcbinfo);
2150
2151 m = counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
2152
2153 error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
2154 + (n + m) * sizeof(struct xtcpcb));
2155 if (error != 0)
2156 return (error);
2157
2158 bzero(&xig, sizeof(xig));
2159 xig.xig_len = sizeof xig;
2160 xig.xig_count = n + m;
2161 xig.xig_gen = gencnt;
2162 xig.xig_sogen = so_gencnt;
2163 error = SYSCTL_OUT(req, &xig, sizeof xig);
2164 if (error)
2165 return (error);
2166
2167 error = syncache_pcblist(req, m, &pcb_count);
2168 if (error)
2169 return (error);
2170
2171 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
2172
2173 INP_INFO_WLOCK(&V_tcbinfo);
2174 for (inp = CK_LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0;
2175 inp != NULL && i < n; inp = CK_LIST_NEXT(inp, inp_list)) {
2176 INP_WLOCK(inp);
2177 if (inp->inp_gencnt <= gencnt) {
2178 /*
2179 * XXX: This use of cr_cansee(), introduced with
2180 * TCP state changes, is not quite right, but for
2181 * now, better than nothing.
2182 */
2183 if (inp->inp_flags & INP_TIMEWAIT) {
2184 if (intotw(inp) != NULL)
2185 error = cr_cansee(req->td->td_ucred,
2186 intotw(inp)->tw_cred);
2187 else
2188 error = EINVAL; /* Skip this inp. */
2189 } else
2190 error = cr_canseeinpcb(req->td->td_ucred, inp);
2191 if (error == 0) {
2192 in_pcbref(inp);
2193 inp_list[i++] = inp;
2194 }
2195 }
2196 INP_WUNLOCK(inp);
2197 }
2198 INP_INFO_WUNLOCK(&V_tcbinfo);
2199 n = i;
2200
2201 error = 0;
2202 for (i = 0; i < n; i++) {
2203 inp = inp_list[i];
2204 INP_RLOCK(inp);
2205 if (inp->inp_gencnt <= gencnt) {
2206 struct xtcpcb xt;
2207
2208 tcp_inptoxtp(inp, &xt);
2209 INP_RUNLOCK(inp);
2210 error = SYSCTL_OUT(req, &xt, sizeof xt);
2211 } else
2212 INP_RUNLOCK(inp);
2213 }
2214 INP_INFO_RLOCK_ET(&V_tcbinfo, et);
2215 for (i = 0; i < n; i++) {
2216 inp = inp_list[i];
2217 INP_RLOCK(inp);
2218 if (!in_pcbrele_rlocked(inp))
2219 INP_RUNLOCK(inp);
2220 }
2221 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
2222
2223 if (!error) {
2224 /*
2225 * Give the user an updated idea of our state.
2226 * If the generation differs from what we told
2227 * her before, she knows that something happened
2228 * while we were processing this request, and it
2229 * might be necessary to retry.
2230 */
2231 INP_LIST_RLOCK(&V_tcbinfo);
2232 xig.xig_gen = V_tcbinfo.ipi_gencnt;
2233 xig.xig_sogen = so_gencnt;
2234 xig.xig_count = V_tcbinfo.ipi_count + pcb_count;
2235 INP_LIST_RUNLOCK(&V_tcbinfo);
2236 error = SYSCTL_OUT(req, &xig, sizeof xig);
2237 }
2238 free(inp_list, M_TEMP);
2239 return (error);
2240 }
2241
2242 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist,
2243 CTLTYPE_OPAQUE | CTLFLAG_RD, NULL, 0,
2244 tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
2245
2246 #ifdef INET
2247 static int
2248 tcp_getcred(SYSCTL_HANDLER_ARGS)
2249 {
2250 struct xucred xuc;
2251 struct sockaddr_in addrs[2];
2252 struct inpcb *inp;
2253 int error;
2254
2255 error = priv_check(req->td, PRIV_NETINET_GETCRED);
2256 if (error)
2257 return (error);
2258 error = SYSCTL_IN(req, addrs, sizeof(addrs));
2259 if (error)
2260 return (error);
2261 inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
2262 addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL);
2263 if (inp != NULL) {
2264 if (inp->inp_socket == NULL)
2265 error = ENOENT;
2266 if (error == 0)
2267 error = cr_canseeinpcb(req->td->td_ucred, inp);
2268 if (error == 0)
2269 cru2x(inp->inp_cred, &xuc);
2270 INP_RUNLOCK(inp);
2271 } else
2272 error = ENOENT;
2273 if (error == 0)
2274 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
2275 return (error);
2276 }
2277
2278 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
2279 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
2280 tcp_getcred, "S,xucred", "Get the xucred of a TCP connection");
2281 #endif /* INET */
2282
2283 #ifdef INET6
2284 static int
2285 tcp6_getcred(SYSCTL_HANDLER_ARGS)
2286 {
2287 struct xucred xuc;
2288 struct sockaddr_in6 addrs[2];
2289 struct inpcb *inp;
2290 int error;
2291 #ifdef INET
2292 int mapped = 0;
2293 #endif
2294
2295 error = priv_check(req->td, PRIV_NETINET_GETCRED);
2296 if (error)
2297 return (error);
2298 error = SYSCTL_IN(req, addrs, sizeof(addrs));
2299 if (error)
2300 return (error);
2301 if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
2302 (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
2303 return (error);
2304 }
2305 if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
2306 #ifdef INET
2307 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
2308 mapped = 1;
2309 else
2310 #endif
2311 return (EINVAL);
2312 }
2313
2314 #ifdef INET
2315 if (mapped == 1)
2316 inp = in_pcblookup(&V_tcbinfo,
2317 *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
2318 addrs[1].sin6_port,
2319 *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
2320 addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL);
2321 else
2322 #endif
2323 inp = in6_pcblookup(&V_tcbinfo,
2324 &addrs[1].sin6_addr, addrs[1].sin6_port,
2325 &addrs[0].sin6_addr, addrs[0].sin6_port,
2326 INPLOOKUP_RLOCKPCB, NULL);
2327 if (inp != NULL) {
2328 if (inp->inp_socket == NULL)
2329 error = ENOENT;
2330 if (error == 0)
2331 error = cr_canseeinpcb(req->td->td_ucred, inp);
2332 if (error == 0)
2333 cru2x(inp->inp_cred, &xuc);
2334 INP_RUNLOCK(inp);
2335 } else
2336 error = ENOENT;
2337 if (error == 0)
2338 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
2339 return (error);
2340 }
2341
2342 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
2343 CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
2344 tcp6_getcred, "S,xucred", "Get the xucred of a TCP6 connection");
2345 #endif /* INET6 */
2346
2347
2348 #ifdef INET
2349 void
2350 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
2351 {
2352 struct ip *ip = vip;
2353 struct tcphdr *th;
2354 struct in_addr faddr;
2355 struct inpcb *inp;
2356 struct tcpcb *tp;
2357 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
2358 struct icmp *icp;
2359 struct in_conninfo inc;
2360 struct epoch_tracker et;
2361 tcp_seq icmp_tcp_seq;
2362 int mtu;
2363
2364 faddr = ((struct sockaddr_in *)sa)->sin_addr;
2365 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
2366 return;
2367
2368 if (cmd == PRC_MSGSIZE)
2369 notify = tcp_mtudisc_notify;
2370 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
2371 cmd == PRC_UNREACH_PORT || cmd == PRC_UNREACH_PROTOCOL ||
2372 cmd == PRC_TIMXCEED_INTRANS) && ip)
2373 notify = tcp_drop_syn_sent;
2374
2375 /*
2376 * Hostdead is ugly because it goes linearly through all PCBs.
2377 * XXX: We never get this from ICMP, otherwise it makes an
2378 * excellent DoS attack on machines with many connections.
2379 */
2380 else if (cmd == PRC_HOSTDEAD)
2381 ip = NULL;
2382 else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
2383 return;
2384
2385 if (ip == NULL) {
2386 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify);
2387 return;
2388 }
2389
2390 icp = (struct icmp *)((caddr_t)ip - offsetof(struct icmp, icmp_ip));
2391 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
2392 INP_INFO_RLOCK_ET(&V_tcbinfo, et);
2393 inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport, ip->ip_src,
2394 th->th_sport, INPLOOKUP_WLOCKPCB, NULL);
2395 if (inp != NULL && PRC_IS_REDIRECT(cmd)) {
2396 /* signal EHOSTDOWN, as it flushes the cached route */
2397 inp = (*notify)(inp, EHOSTDOWN);
2398 goto out;
2399 }
2400 icmp_tcp_seq = th->th_seq;
2401 if (inp != NULL) {
2402 if (!(inp->inp_flags & INP_TIMEWAIT) &&
2403 !(inp->inp_flags & INP_DROPPED) &&
2404 !(inp->inp_socket == NULL)) {
2405 tp = intotcpcb(inp);
2406 if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
2407 SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
2408 if (cmd == PRC_MSGSIZE) {
2409 /*
2410 * MTU discovery:
2411 * If we got a needfrag set the MTU
2412 * in the route to the suggested new
2413 * value (if given) and then notify.
2414 */
2415 mtu = ntohs(icp->icmp_nextmtu);
2416 /*
2417 * If no alternative MTU was
2418 * proposed, try the next smaller
2419 * one.
2420 */
2421 if (!mtu)
2422 mtu = ip_next_mtu(
2423 ntohs(ip->ip_len), 1);
2424 if (mtu < V_tcp_minmss +
2425 sizeof(struct tcpiphdr))
2426 mtu = V_tcp_minmss +
2427 sizeof(struct tcpiphdr);
2428 /*
2429 * Only process the offered MTU if it
2430 * is smaller than the current one.
2431 */
2432 if (mtu < tp->t_maxseg +
2433 sizeof(struct tcpiphdr)) {
2434 bzero(&inc, sizeof(inc));
2435 inc.inc_faddr = faddr;
2436 inc.inc_fibnum =
2437 inp->inp_inc.inc_fibnum;
2438 tcp_hc_updatemtu(&inc, mtu);
2439 tcp_mtudisc(inp, mtu);
2440 }
2441 } else
2442 inp = (*notify)(inp,
2443 inetctlerrmap[cmd]);
2444 }
2445 }
2446 } else {
2447 bzero(&inc, sizeof(inc));
2448 inc.inc_fport = th->th_dport;
2449 inc.inc_lport = th->th_sport;
2450 inc.inc_faddr = faddr;
2451 inc.inc_laddr = ip->ip_src;
2452 syncache_unreach(&inc, icmp_tcp_seq);
2453 }
2454 out:
2455 if (inp != NULL)
2456 INP_WUNLOCK(inp);
2457 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
2458 }
2459 #endif /* INET */
2460
2461 #ifdef INET6
2462 void
2463 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
2464 {
2465 struct in6_addr *dst;
2466 struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
2467 struct ip6_hdr *ip6;
2468 struct mbuf *m;
2469 struct inpcb *inp;
2470 struct tcpcb *tp;
2471 struct icmp6_hdr *icmp6;
2472 struct ip6ctlparam *ip6cp = NULL;
2473 const struct sockaddr_in6 *sa6_src = NULL;
2474 struct in_conninfo inc;
2475 struct epoch_tracker et;
2476 struct tcp_ports {
2477 uint16_t th_sport;
2478 uint16_t th_dport;
2479 } t_ports;
2480 tcp_seq icmp_tcp_seq;
2481 unsigned int mtu;
2482 unsigned int off;
2483
2484 if (sa->sa_family != AF_INET6 ||
2485 sa->sa_len != sizeof(struct sockaddr_in6))
2486 return;
2487
2488 /* if the parameter is from icmp6, decode it. */
2489 if (d != NULL) {
2490 ip6cp = (struct ip6ctlparam *)d;
2491 icmp6 = ip6cp->ip6c_icmp6;
2492 m = ip6cp->ip6c_m;
2493 ip6 = ip6cp->ip6c_ip6;
2494 off = ip6cp->ip6c_off;
2495 sa6_src = ip6cp->ip6c_src;
2496 dst = ip6cp->ip6c_finaldst;
2497 } else {
2498 m = NULL;
2499 ip6 = NULL;
2500 off = 0; /* fool gcc */
2501 sa6_src = &sa6_any;
2502 dst = NULL;
2503 }
2504
2505 if (cmd == PRC_MSGSIZE)
2506 notify = tcp_mtudisc_notify;
2507 else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
2508 cmd == PRC_UNREACH_PORT || cmd == PRC_UNREACH_PROTOCOL ||
2509 cmd == PRC_TIMXCEED_INTRANS) && ip6 != NULL)
2510 notify = tcp_drop_syn_sent;
2511
2512 /*
2513 * Hostdead is ugly because it goes linearly through all PCBs.
2514 * XXX: We never get this from ICMP, otherwise it makes an
2515 * excellent DoS attack on machines with many connections.
2516 */
2517 else if (cmd == PRC_HOSTDEAD)
2518 ip6 = NULL;
2519 else if ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)
2520 return;
2521
2522 if (ip6 == NULL) {
2523 in6_pcbnotify(&V_tcbinfo, sa, 0,
2524 (const struct sockaddr *)sa6_src,
2525 0, cmd, NULL, notify);
2526 return;
2527 }
2528
2529 /* Check if we can safely get the ports from the tcp hdr */
2530 if (m == NULL ||
2531 (m->m_pkthdr.len <
2532 (int32_t) (off + sizeof(struct tcp_ports)))) {
2533 return;
2534 }
2535 bzero(&t_ports, sizeof(struct tcp_ports));
2536 m_copydata(m, off, sizeof(struct tcp_ports), (caddr_t)&t_ports);
2537 INP_INFO_RLOCK_ET(&V_tcbinfo, et);
2538 inp = in6_pcblookup(&V_tcbinfo, &ip6->ip6_dst, t_ports.th_dport,
2539 &ip6->ip6_src, t_ports.th_sport, INPLOOKUP_WLOCKPCB, NULL);
2540 if (inp != NULL && PRC_IS_REDIRECT(cmd)) {
2541 /* signal EHOSTDOWN, as it flushes the cached route */
2542 inp = (*notify)(inp, EHOSTDOWN);
2543 goto out;
2544 }
2545 off += sizeof(struct tcp_ports);
2546 if (m->m_pkthdr.len < (int32_t) (off + sizeof(tcp_seq))) {
2547 goto out;
2548 }
2549 m_copydata(m, off, sizeof(tcp_seq), (caddr_t)&icmp_tcp_seq);
2550 if (inp != NULL) {
2551 if (!(inp->inp_flags & INP_TIMEWAIT) &&
2552 !(inp->inp_flags & INP_DROPPED) &&
2553 !(inp->inp_socket == NULL)) {
2554 tp = intotcpcb(inp);
2555 if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
2556 SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
2557 if (cmd == PRC_MSGSIZE) {
2558 /*
2559 * MTU discovery:
2560 * If we got a needfrag set the MTU
2561 * in the route to the suggested new
2562 * value (if given) and then notify.
2563 */
2564 mtu = ntohl(icmp6->icmp6_mtu);
2565 /*
2566 * If no alternative MTU was
2567 * proposed, or the proposed
2568 * MTU was too small, set to
2569 * the min.
2570 */
2571 if (mtu < IPV6_MMTU)
2572 mtu = IPV6_MMTU - 8;
2573 bzero(&inc, sizeof(inc));
2574 inc.inc_fibnum = M_GETFIB(m);
2575 inc.inc_flags |= INC_ISIPV6;
2576 inc.inc6_faddr = *dst;
2577 if (in6_setscope(&inc.inc6_faddr,
2578 m->m_pkthdr.rcvif, NULL))
2579 goto out;
2580 /*
2581 * Only process the offered MTU if it
2582 * is smaller than the current one.
2583 */
2584 if (mtu < tp->t_maxseg +
2585 sizeof (struct tcphdr) +
2586 sizeof (struct ip6_hdr)) {
2587 tcp_hc_updatemtu(&inc, mtu);
2588 tcp_mtudisc(inp, mtu);
2589 ICMP6STAT_INC(icp6s_pmtuchg);
2590 }
2591 } else
2592 inp = (*notify)(inp,
2593 inet6ctlerrmap[cmd]);
2594 }
2595 }
2596 } else {
2597 bzero(&inc, sizeof(inc));
2598 inc.inc_fibnum = M_GETFIB(m);
2599 inc.inc_flags |= INC_ISIPV6;
2600 inc.inc_fport = t_ports.th_dport;
2601 inc.inc_lport = t_ports.th_sport;
2602 inc.inc6_faddr = *dst;
2603 inc.inc6_laddr = ip6->ip6_src;
2604 syncache_unreach(&inc, icmp_tcp_seq);
2605 }
2606 out:
2607 if (inp != NULL)
2608 INP_WUNLOCK(inp);
2609 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
2610 }
2611 #endif /* INET6 */
2612
2613 static uint32_t
2614 tcp_keyed_hash(struct in_conninfo *inc, u_char *key, u_int len)
2615 {
2616 MD5_CTX ctx;
2617 uint32_t hash[4];
2618
2619 MD5Init(&ctx);
2620 MD5Update(&ctx, &inc->inc_fport, sizeof(uint16_t));
2621 MD5Update(&ctx, &inc->inc_lport, sizeof(uint16_t));
2622 switch (inc->inc_flags & INC_ISIPV6) {
2623 #ifdef INET
2624 case 0:
2625 MD5Update(&ctx, &inc->inc_faddr, sizeof(struct in_addr));
2626 MD5Update(&ctx, &inc->inc_laddr, sizeof(struct in_addr));
2627 break;
2628 #endif
2629 #ifdef INET6
2630 case INC_ISIPV6:
2631 MD5Update(&ctx, &inc->inc6_faddr, sizeof(struct in6_addr));
2632 MD5Update(&ctx, &inc->inc6_laddr, sizeof(struct in6_addr));
2633 break;
2634 #endif
2635 }
2636 MD5Update(&ctx, key, len);
2637 MD5Final((unsigned char *)hash, &ctx);
2638
2639 return (hash[0]);
2640 }
2641
2642 uint32_t
2643 tcp_new_ts_offset(struct in_conninfo *inc)
2644 {
2645 return (tcp_keyed_hash(inc, V_ts_offset_secret,
2646 sizeof(V_ts_offset_secret)));
2647 }
2648
2649 /*
2650 * Following is where TCP initial sequence number generation occurs.
2651 *
2652 * There are two places where we must use initial sequence numbers:
2653 * 1. In SYN-ACK packets.
2654 * 2. In SYN packets.
2655 *
2656 * All ISNs for SYN-ACK packets are generated by the syncache. See
2657 * tcp_syncache.c for details.
2658 *
2659 * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
2660 * depends on this property. In addition, these ISNs should be
2661 * unguessable so as to prevent connection hijacking. To satisfy
2662 * the requirements of this situation, the algorithm outlined in
2663 * RFC 1948 is used, with only small modifications.
2664 *
2665 * Implementation details:
2666 *
2667 * Time is based off the system timer, and is corrected so that it
2668 * increases by one megabyte per second. This allows for proper
2669 * recycling on high speed LANs while still leaving over an hour
2670 * before rollover.
2671 *
2672 * As reading the *exact* system time is too expensive to be done
2673 * whenever setting up a TCP connection, we increment the time
2674 * offset in two ways. First, a small random positive increment
2675 * is added to isn_offset for each connection that is set up.
2676 * Second, the function tcp_isn_tick fires once per clock tick
2677 * and increments isn_offset as necessary so that sequence numbers
2678 * are incremented at approximately ISN_BYTES_PER_SECOND. The
2679 * random positive increments serve only to ensure that the same
2680 * exact sequence number is never sent out twice (as could otherwise
2681 * happen when a port is recycled in less than the system tick
2682 * interval.)
2683 *
2684 * net.inet.tcp.isn_reseed_interval controls the number of seconds
2685 * between seeding of isn_secret. This is normally set to zero,
2686 * as reseeding should not be necessary.
2687 *
2688 * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
2689 * isn_offset_old, and isn_ctx is performed using the ISN lock. In
2690 * general, this means holding an exclusive (write) lock.
2691 */
2692
2693 #define ISN_BYTES_PER_SECOND 1048576
2694 #define ISN_STATIC_INCREMENT 4096
2695 #define ISN_RANDOM_INCREMENT (4096 - 1)
2696 #define ISN_SECRET_LENGTH 32
2697
2698 VNET_DEFINE_STATIC(u_char, isn_secret[ISN_SECRET_LENGTH]);
2699 VNET_DEFINE_STATIC(int, isn_last);
2700 VNET_DEFINE_STATIC(int, isn_last_reseed);
2701 VNET_DEFINE_STATIC(u_int32_t, isn_offset);
2702 VNET_DEFINE_STATIC(u_int32_t, isn_offset_old);
2703
2704 #define V_isn_secret VNET(isn_secret)
2705 #define V_isn_last VNET(isn_last)
2706 #define V_isn_last_reseed VNET(isn_last_reseed)
2707 #define V_isn_offset VNET(isn_offset)
2708 #define V_isn_offset_old VNET(isn_offset_old)
2709
2710 tcp_seq
2711 tcp_new_isn(struct in_conninfo *inc)
2712 {
2713 tcp_seq new_isn;
2714 u_int32_t projected_offset;
2715
2716 ISN_LOCK();
2717 /* Seed if this is the first use, reseed if requested. */
2718 if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) &&
2719 (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz)
2720 < (u_int)ticks))) {
2721 arc4rand(&V_isn_secret, sizeof(V_isn_secret), 0);
2722 V_isn_last_reseed = ticks;
2723 }
2724
2725 /* Compute the md5 hash and return the ISN. */
2726 new_isn = (tcp_seq)tcp_keyed_hash(inc, V_isn_secret,
2727 sizeof(V_isn_secret));
2728 V_isn_offset += ISN_STATIC_INCREMENT +
2729 (arc4random() & ISN_RANDOM_INCREMENT);
2730 if (ticks != V_isn_last) {
2731 projected_offset = V_isn_offset_old +
2732 ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last);
2733 if (SEQ_GT(projected_offset, V_isn_offset))
2734 V_isn_offset = projected_offset;
2735 V_isn_offset_old = V_isn_offset;
2736 V_isn_last = ticks;
2737 }
2738 new_isn += V_isn_offset;
2739 ISN_UNLOCK();
2740 return (new_isn);
2741 }
2742
2743 /*
2744 * When a specific ICMP unreachable message is received and the
2745 * connection state is SYN-SENT, drop the connection. This behavior
2746 * is controlled by the icmp_may_rst sysctl.
2747 */
2748 struct inpcb *
2749 tcp_drop_syn_sent(struct inpcb *inp, int errno)
2750 {
2751 struct tcpcb *tp;
2752
2753 INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
2754 INP_WLOCK_ASSERT(inp);
2755
2756 if ((inp->inp_flags & INP_TIMEWAIT) ||
2757 (inp->inp_flags & INP_DROPPED))
2758 return (inp);
2759
2760 tp = intotcpcb(inp);
2761 if (tp->t_state != TCPS_SYN_SENT)
2762 return (inp);
2763
2764 if (IS_FASTOPEN(tp->t_flags))
2765 tcp_fastopen_disable_path(tp);
2766
2767 tp = tcp_drop(tp, errno);
2768 if (tp != NULL)
2769 return (inp);
2770 else
2771 return (NULL);
2772 }
2773
2774 /*
2775 * When `need fragmentation' ICMP is received, update our idea of the MSS
2776 * based on the new value. Also nudge TCP to send something, since we
2777 * know the packet we just sent was dropped.
2778 * This duplicates some code in the tcp_mss() function in tcp_input.c.
2779 */
2780 static struct inpcb *
2781 tcp_mtudisc_notify(struct inpcb *inp, int error)
2782 {
2783
2784 tcp_mtudisc(inp, -1);
2785 return (inp);
2786 }
2787
2788 static void
2789 tcp_mtudisc(struct inpcb *inp, int mtuoffer)
2790 {
2791 struct tcpcb *tp;
2792 struct socket *so;
2793
2794 INP_WLOCK_ASSERT(inp);
2795 if ((inp->inp_flags & INP_TIMEWAIT) ||
2796 (inp->inp_flags & INP_DROPPED))
2797 return;
2798
2799 tp = intotcpcb(inp);
2800 KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
2801
2802 tcp_mss_update(tp, -1, mtuoffer, NULL, NULL);
2803
2804 so = inp->inp_socket;
2805 SOCKBUF_LOCK(&so->so_snd);
2806 /* If the mss is larger than the socket buffer, decrease the mss. */
2807 if (so->so_snd.sb_hiwat < tp->t_maxseg)
2808 tp->t_maxseg = so->so_snd.sb_hiwat;
2809 SOCKBUF_UNLOCK(&so->so_snd);
2810
2811 TCPSTAT_INC(tcps_mturesent);
2812 tp->t_rtttime = 0;
2813 tp->snd_nxt = tp->snd_una;
2814 tcp_free_sackholes(tp);
2815 tp->snd_recover = tp->snd_max;
2816 if (tp->t_flags & TF_SACK_PERMIT)
2817 EXIT_FASTRECOVERY(tp->t_flags);
2818 tp->t_fb->tfb_tcp_output(tp);
2819 }
2820
2821 #ifdef INET
2822 /*
2823 * Look-up the routing entry to the peer of this inpcb. If no route
2824 * is found and it cannot be allocated, then return 0. This routine
2825 * is called by TCP routines that access the rmx structure and by
2826 * tcp_mss_update to get the peer/interface MTU.
2827 */
2828 uint32_t
2829 tcp_maxmtu(struct in_conninfo *inc, struct tcp_ifcap *cap)
2830 {
2831 struct nhop4_extended nh4;
2832 struct ifnet *ifp;
2833 uint32_t maxmtu = 0;
2834
2835 KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
2836
2837 if (inc->inc_faddr.s_addr != INADDR_ANY) {
2838
2839 if (fib4_lookup_nh_ext(inc->inc_fibnum, inc->inc_faddr,
2840 NHR_REF, 0, &nh4) != 0)
2841 return (0);
2842
2843 ifp = nh4.nh_ifp;
2844 maxmtu = nh4.nh_mtu;
2845
2846 /* Report additional interface capabilities. */
2847 if (cap != NULL) {
2848 if (ifp->if_capenable & IFCAP_TSO4 &&
2849 ifp->if_hwassist & CSUM_TSO) {
2850 cap->ifcap |= CSUM_TSO;
2851 cap->tsomax = ifp->if_hw_tsomax;
2852 cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
2853 cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
2854 }
2855 }
2856 fib4_free_nh_ext(inc->inc_fibnum, &nh4);
2857 }
2858 return (maxmtu);
2859 }
2860 #endif /* INET */
2861
2862 #ifdef INET6
2863 uint32_t
2864 tcp_maxmtu6(struct in_conninfo *inc, struct tcp_ifcap *cap)
2865 {
2866 struct nhop6_extended nh6;
2867 struct in6_addr dst6;
2868 uint32_t scopeid;
2869 struct ifnet *ifp;
2870 uint32_t maxmtu = 0;
2871
2872 KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
2873
2874 if (inc->inc_flags & INC_IPV6MINMTU)
2875 return (IPV6_MMTU);
2876
2877 if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
2878 in6_splitscope(&inc->inc6_faddr, &dst6, &scopeid);
2879 if (fib6_lookup_nh_ext(inc->inc_fibnum, &dst6, scopeid, 0,
2880 0, &nh6) != 0)
2881 return (0);
2882
2883 ifp = nh6.nh_ifp;
2884 maxmtu = nh6.nh_mtu;
2885
2886 /* Report additional interface capabilities. */
2887 if (cap != NULL) {
2888 if (ifp->if_capenable & IFCAP_TSO6 &&
2889 ifp->if_hwassist & CSUM_TSO) {
2890 cap->ifcap |= CSUM_TSO;
2891 cap->tsomax = ifp->if_hw_tsomax;
2892 cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
2893 cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
2894 }
2895 }
2896 fib6_free_nh_ext(inc->inc_fibnum, &nh6);
2897 }
2898
2899 return (maxmtu);
2900 }
2901 #endif /* INET6 */
2902
2903 /*
2904 * Calculate effective SMSS per RFC5681 definition for a given TCP
2905 * connection at its current state, taking into account SACK and etc.
2906 */
2907 u_int
2908 tcp_maxseg(const struct tcpcb *tp)
2909 {
2910 u_int optlen;
2911
2912 if (tp->t_flags & TF_NOOPT)
2913 return (tp->t_maxseg);
2914
2915 /*
2916 * Here we have a simplified code from tcp_addoptions(),
2917 * without a proper loop, and having most of paddings hardcoded.
2918 * We might make mistakes with padding here in some edge cases,
2919 * but this is harmless, since result of tcp_maxseg() is used
2920 * only in cwnd and ssthresh estimations.
2921 */
2922 #define PAD(len) ((((len) / 4) + !!((len) % 4)) * 4)
2923 if (TCPS_HAVEESTABLISHED(tp->t_state)) {
2924 if (tp->t_flags & TF_RCVD_TSTMP)
2925 optlen = TCPOLEN_TSTAMP_APPA;
2926 else
2927 optlen = 0;
2928 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
2929 if (tp->t_flags & TF_SIGNATURE)
2930 optlen += PAD(TCPOLEN_SIGNATURE);
2931 #endif
2932 if ((tp->t_flags & TF_SACK_PERMIT) && tp->rcv_numsacks > 0) {
2933 optlen += TCPOLEN_SACKHDR;
2934 optlen += tp->rcv_numsacks * TCPOLEN_SACK;
2935 optlen = PAD(optlen);
2936 }
2937 } else {
2938 if (tp->t_flags & TF_REQ_TSTMP)
2939 optlen = TCPOLEN_TSTAMP_APPA;
2940 else
2941 optlen = PAD(TCPOLEN_MAXSEG);
2942 if (tp->t_flags & TF_REQ_SCALE)
2943 optlen += PAD(TCPOLEN_WINDOW);
2944 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
2945 if (tp->t_flags & TF_SIGNATURE)
2946 optlen += PAD(TCPOLEN_SIGNATURE);
2947 #endif
2948 if (tp->t_flags & TF_SACK_PERMIT)
2949 optlen += PAD(TCPOLEN_SACK_PERMITTED);
2950 }
2951 #undef PAD
2952 optlen = min(optlen, TCP_MAXOLEN);
2953 return (tp->t_maxseg - optlen);
2954 }
2955
2956 static int
2957 sysctl_drop(SYSCTL_HANDLER_ARGS)
2958 {
2959 /* addrs[0] is a foreign socket, addrs[1] is a local one. */
2960 struct sockaddr_storage addrs[2];
2961 struct inpcb *inp;
2962 struct tcpcb *tp;
2963 struct tcptw *tw;
2964 struct sockaddr_in *fin, *lin;
2965 struct epoch_tracker et;
2966 #ifdef INET6
2967 struct sockaddr_in6 *fin6, *lin6;
2968 #endif
2969 int error;
2970
2971 inp = NULL;
2972 fin = lin = NULL;
2973 #ifdef INET6
2974 fin6 = lin6 = NULL;
2975 #endif
2976 error = 0;
2977
2978 if (req->oldptr != NULL || req->oldlen != 0)
2979 return (EINVAL);
2980 if (req->newptr == NULL)
2981 return (EPERM);
2982 if (req->newlen < sizeof(addrs))
2983 return (ENOMEM);
2984 error = SYSCTL_IN(req, &addrs, sizeof(addrs));
2985 if (error)
2986 return (error);
2987
2988 switch (addrs[0].ss_family) {
2989 #ifdef INET6
2990 case AF_INET6:
2991 fin6 = (struct sockaddr_in6 *)&addrs[0];
2992 lin6 = (struct sockaddr_in6 *)&addrs[1];
2993 if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
2994 lin6->sin6_len != sizeof(struct sockaddr_in6))
2995 return (EINVAL);
2996 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
2997 if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
2998 return (EINVAL);
2999 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
3000 in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
3001 fin = (struct sockaddr_in *)&addrs[0];
3002 lin = (struct sockaddr_in *)&addrs[1];
3003 break;
3004 }
3005 error = sa6_embedscope(fin6, V_ip6_use_defzone);
3006 if (error)
3007 return (error);
3008 error = sa6_embedscope(lin6, V_ip6_use_defzone);
3009 if (error)
3010 return (error);
3011 break;
3012 #endif
3013 #ifdef INET
3014 case AF_INET:
3015 fin = (struct sockaddr_in *)&addrs[0];
3016 lin = (struct sockaddr_in *)&addrs[1];
3017 if (fin->sin_len != sizeof(struct sockaddr_in) ||
3018 lin->sin_len != sizeof(struct sockaddr_in))
3019 return (EINVAL);
3020 break;
3021 #endif
3022 default:
3023 return (EINVAL);
3024 }
3025 INP_INFO_RLOCK_ET(&V_tcbinfo, et);
3026 switch (addrs[0].ss_family) {
3027 #ifdef INET6
3028 case AF_INET6:
3029 inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
3030 fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
3031 INPLOOKUP_WLOCKPCB, NULL);
3032 break;
3033 #endif
3034 #ifdef INET
3035 case AF_INET:
3036 inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
3037 lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
3038 break;
3039 #endif
3040 }
3041 if (inp != NULL) {
3042 if (inp->inp_flags & INP_TIMEWAIT) {
3043 /*
3044 * XXXRW: There currently exists a state where an
3045 * inpcb is present, but its timewait state has been
3046 * discarded. For now, don't allow dropping of this
3047 * type of inpcb.
3048 */
3049 tw = intotw(inp);
3050 if (tw != NULL)
3051 tcp_twclose(tw, 0);
3052 else
3053 INP_WUNLOCK(inp);
3054 } else if (!(inp->inp_flags & INP_DROPPED) &&
3055 !(inp->inp_socket->so_options & SO_ACCEPTCONN)) {
3056 tp = intotcpcb(inp);
3057 tp = tcp_drop(tp, ECONNABORTED);
3058 if (tp != NULL)
3059 INP_WUNLOCK(inp);
3060 } else
3061 INP_WUNLOCK(inp);
3062 } else
3063 error = ESRCH;
3064 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
3065 return (error);
3066 }
3067
3068 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
3069 CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP, NULL,
3070 0, sysctl_drop, "", "Drop TCP connection");
3071
3072 /*
3073 * Generate a standardized TCP log line for use throughout the
3074 * tcp subsystem. Memory allocation is done with M_NOWAIT to
3075 * allow use in the interrupt context.
3076 *
3077 * NB: The caller MUST free(s, M_TCPLOG) the returned string.
3078 * NB: The function may return NULL if memory allocation failed.
3079 *
3080 * Due to header inclusion and ordering limitations the struct ip
3081 * and ip6_hdr pointers have to be passed as void pointers.
3082 */
3083 char *
3084 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
3085 const void *ip6hdr)
3086 {
3087
3088 /* Is logging enabled? */
3089 if (tcp_log_in_vain == 0)
3090 return (NULL);
3091
3092 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
3093 }
3094
3095 char *
3096 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
3097 const void *ip6hdr)
3098 {
3099
3100 /* Is logging enabled? */
3101 if (tcp_log_debug == 0)
3102 return (NULL);
3103
3104 return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
3105 }
3106
3107 static char *
3108 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
3109 const void *ip6hdr)
3110 {
3111 char *s, *sp;
3112 size_t size;
3113 struct ip *ip;
3114 #ifdef INET6
3115 const struct ip6_hdr *ip6;
3116
3117 ip6 = (const struct ip6_hdr *)ip6hdr;
3118 #endif /* INET6 */
3119 ip = (struct ip *)ip4hdr;
3120
3121 /*
3122 * The log line looks like this:
3123 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>"
3124 */
3125 size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") +
3126 sizeof(PRINT_TH_FLAGS) + 1 +
3127 #ifdef INET6
3128 2 * INET6_ADDRSTRLEN;
3129 #else
3130 2 * INET_ADDRSTRLEN;
3131 #endif /* INET6 */
3132
3133 s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT);
3134 if (s == NULL)
3135 return (NULL);
3136
3137 strcat(s, "TCP: [");
3138 sp = s + strlen(s);
3139
3140 if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) {
3141 inet_ntoa_r(inc->inc_faddr, sp);
3142 sp = s + strlen(s);
3143 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
3144 sp = s + strlen(s);
3145 inet_ntoa_r(inc->inc_laddr, sp);
3146 sp = s + strlen(s);
3147 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
3148 #ifdef INET6
3149 } else if (inc) {
3150 ip6_sprintf(sp, &inc->inc6_faddr);
3151 sp = s + strlen(s);
3152 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
3153 sp = s + strlen(s);
3154 ip6_sprintf(sp, &inc->inc6_laddr);
3155 sp = s + strlen(s);
3156 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
3157 } else if (ip6 && th) {
3158 ip6_sprintf(sp, &ip6->ip6_src);
3159 sp = s + strlen(s);
3160 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
3161 sp = s + strlen(s);
3162 ip6_sprintf(sp, &ip6->ip6_dst);
3163 sp = s + strlen(s);
3164 sprintf(sp, "]:%i", ntohs(th->th_dport));
3165 #endif /* INET6 */
3166 #ifdef INET
3167 } else if (ip && th) {
3168 inet_ntoa_r(ip->ip_src, sp);
3169 sp = s + strlen(s);
3170 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
3171 sp = s + strlen(s);
3172 inet_ntoa_r(ip->ip_dst, sp);
3173 sp = s + strlen(s);
3174 sprintf(sp, "]:%i", ntohs(th->th_dport));
3175 #endif /* INET */
3176 } else {
3177 free(s, M_TCPLOG);
3178 return (NULL);
3179 }
3180 sp = s + strlen(s);
3181 if (th)
3182 sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS);
3183 if (*(s + size - 1) != '\0')
3184 panic("%s: string too long", __func__);
3185 return (s);
3186 }
3187
3188 /*
3189 * A subroutine which makes it easy to track TCP state changes with DTrace.
3190 * This function shouldn't be called for t_state initializations that don't
3191 * correspond to actual TCP state transitions.
3192 */
3193 void
3194 tcp_state_change(struct tcpcb *tp, int newstate)
3195 {
3196 #if defined(KDTRACE_HOOKS)
3197 int pstate = tp->t_state;
3198 #endif
3199
3200 TCPSTATES_DEC(tp->t_state);
3201 TCPSTATES_INC(newstate);
3202 tp->t_state = newstate;
3203 TCP_PROBE6(state__change, NULL, tp, NULL, tp, NULL, pstate);
3204 }
3205
3206 /*
3207 * Create an external-format (``xtcpcb'') structure using the information in
3208 * the kernel-format tcpcb structure pointed to by tp. This is done to
3209 * reduce the spew of irrelevant information over this interface, to isolate
3210 * user code from changes in the kernel structure, and potentially to provide
3211 * information-hiding if we decide that some of this information should be
3212 * hidden from users.
3213 */
3214 void
3215 tcp_inptoxtp(const struct inpcb *inp, struct xtcpcb *xt)
3216 {
3217 struct tcpcb *tp = intotcpcb(inp);
3218 sbintime_t now;
3219
3220 bzero(xt, sizeof(*xt));
3221 if (inp->inp_flags & INP_TIMEWAIT) {
3222 xt->t_state = TCPS_TIME_WAIT;
3223 } else {
3224 xt->t_state = tp->t_state;
3225 xt->t_logstate = tp->t_logstate;
3226 xt->t_flags = tp->t_flags;
3227 xt->t_sndzerowin = tp->t_sndzerowin;
3228 xt->t_sndrexmitpack = tp->t_sndrexmitpack;
3229 xt->t_rcvoopack = tp->t_rcvoopack;
3230
3231 now = getsbinuptime();
3232 #define COPYTIMER(ttt) do { \
3233 if (callout_active(&tp->t_timers->ttt)) \
3234 xt->ttt = (tp->t_timers->ttt.c_time - now) / \
3235 SBT_1MS; \
3236 else \
3237 xt->ttt = 0; \
3238 } while (0)
3239 COPYTIMER(tt_delack);
3240 COPYTIMER(tt_rexmt);
3241 COPYTIMER(tt_persist);
3242 COPYTIMER(tt_keep);
3243 COPYTIMER(tt_2msl);
3244 #undef COPYTIMER
3245 xt->t_rcvtime = 1000 * (ticks - tp->t_rcvtime) / hz;
3246
3247 bcopy(tp->t_fb->tfb_tcp_block_name, xt->xt_stack,
3248 TCP_FUNCTION_NAME_LEN_MAX);
3249 #ifdef TCP_BLACKBOX
3250 (void)tcp_log_get_id(tp, xt->xt_logid);
3251 #endif
3252 }
3253
3254 xt->xt_len = sizeof(struct xtcpcb);
3255 in_pcbtoxinpcb(inp, &xt->xt_inp);
3256 if (inp->inp_socket == NULL)
3257 xt->xt_inp.xi_socket.xso_protocol = IPPROTO_TCP;
3258 }
Cache object: f79eef7815bd7e81cd820fa9332cf854
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