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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("$FreeBSD$");
36
37 #include "opt_inet.h"
38 #include "opt_inet6.h"
39 #include "opt_ipsec.h"
40 #include "opt_kern_tls.h"
41 #include "opt_tcpdebug.h"
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/arb.h>
46 #include <sys/callout.h>
47 #include <sys/eventhandler.h>
48 #ifdef TCP_HHOOK
49 #include <sys/hhook.h>
50 #endif
51 #include <sys/kernel.h>
52 #ifdef TCP_HHOOK
53 #include <sys/khelp.h>
54 #endif
55 #ifdef KERN_TLS
56 #include <sys/ktls.h>
57 #endif
58 #include <sys/qmath.h>
59 #include <sys/stats.h>
60 #include <sys/sysctl.h>
61 #include <sys/jail.h>
62 #include <sys/malloc.h>
63 #include <sys/refcount.h>
64 #include <sys/mbuf.h>
65 #include <sys/priv.h>
66 #include <sys/proc.h>
67 #include <sys/sdt.h>
68 #include <sys/socket.h>
69 #include <sys/socketvar.h>
70 #include <sys/protosw.h>
71 #include <sys/random.h>
72
73 #include <vm/uma.h>
74
75 #include <net/route.h>
76 #include <net/route/nhop.h>
77 #include <net/if.h>
78 #include <net/if_var.h>
79 #include <net/vnet.h>
80
81 #include <netinet/in.h>
82 #include <netinet/in_fib.h>
83 #include <netinet/in_kdtrace.h>
84 #include <netinet/in_pcb.h>
85 #include <netinet/in_systm.h>
86 #include <netinet/in_var.h>
87 #include <netinet/ip.h>
88 #include <netinet/ip_icmp.h>
89 #include <netinet/ip_var.h>
90 #ifdef INET6
91 #include <netinet/icmp6.h>
92 #include <netinet/ip6.h>
93 #include <netinet6/in6_fib.h>
94 #include <netinet6/in6_pcb.h>
95 #include <netinet6/ip6_var.h>
96 #include <netinet6/scope6_var.h>
97 #include <netinet6/nd6.h>
98 #endif
99
100 #include <netinet/tcp.h>
101 #ifdef INVARIANTS
102 #define TCPSTATES
103 #endif
104 #include <netinet/tcp_fsm.h>
105 #include <netinet/tcp_seq.h>
106 #include <netinet/tcp_timer.h>
107 #include <netinet/tcp_var.h>
108 #include <netinet/tcp_log_buf.h>
109 #include <netinet/tcp_syncache.h>
110 #include <netinet/tcp_hpts.h>
111 #include <netinet/cc/cc.h>
112 #ifdef INET6
113 #include <netinet6/tcp6_var.h>
114 #endif
115 #include <netinet/tcpip.h>
116 #include <netinet/tcp_fastopen.h>
117 #ifdef TCPPCAP
118 #include <netinet/tcp_pcap.h>
119 #endif
120 #ifdef TCPDEBUG
121 #include <netinet/tcp_debug.h>
122 #endif
123 #ifdef INET6
124 #include <netinet6/ip6protosw.h>
125 #endif
126 #ifdef TCP_OFFLOAD
127 #include <netinet/tcp_offload.h>
128 #endif
129 #include <netinet/udp.h>
130 #include <netinet/udp_var.h>
131
132 #include <netipsec/ipsec_support.h>
133
134 #include <machine/in_cksum.h>
135 #include <crypto/siphash/siphash.h>
136
137 #include <security/mac/mac_framework.h>
138
139 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS;
140 #ifdef INET6
141 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS;
142 #endif
143
144 #ifdef NETFLIX_EXP_DETECTION
145 /*  Sack attack detection thresholds and such */
146 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, sack_attack,
147     CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
148     "Sack Attack detection thresholds");
149 int32_t tcp_force_detection = 0;
150 SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, force_detection,
151     CTLFLAG_RW,
152     &tcp_force_detection, 0,
153     "Do we force detection even if the INP has it off?");
154 int32_t tcp_sack_to_ack_thresh = 700;   /* 70 % */
155 SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, sack_to_ack_thresh,
156     CTLFLAG_RW,
157     &tcp_sack_to_ack_thresh, 700,
158     "Percentage of sacks to acks we must see above (10.1 percent is 101)?");
159 int32_t tcp_sack_to_move_thresh = 600;  /* 60 % */
160 SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, move_thresh,
161     CTLFLAG_RW,
162     &tcp_sack_to_move_thresh, 600,
163     "Percentage of sack moves we must see above (10.1 percent is 101)");
164 int32_t tcp_restoral_thresh = 650;      /* 65 % (sack:2:ack -5%) */
165 SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, restore_thresh,
166     CTLFLAG_RW,
167     &tcp_restoral_thresh, 550,
168     "Percentage of sack to ack percentage we must see below to restore(10.1 percent is 101)");
169 int32_t tcp_sad_decay_val = 800;
170 SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, decay_per,
171     CTLFLAG_RW,
172     &tcp_sad_decay_val, 800,
173     "The decay percentage (10.1 percent equals 101 )");
174 int32_t tcp_map_minimum = 500;
175 SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, nummaps,
176     CTLFLAG_RW,
177     &tcp_map_minimum, 500,
178     "Number of Map enteries before we start detection");
179 int32_t tcp_attack_on_turns_on_logging = 0;
180 SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, attacks_logged,
181     CTLFLAG_RW,
182     &tcp_attack_on_turns_on_logging, 0,
183    "When we have a positive hit on attack, do we turn on logging?");
184 int32_t tcp_sad_pacing_interval = 2000;
185 SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, sad_pacing_int,
186     CTLFLAG_RW,
187     &tcp_sad_pacing_interval, 2000,
188     "What is the minimum pacing interval for a classified attacker?");
189
190 int32_t tcp_sad_low_pps = 100;
191 SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, sad_low_pps,
192     CTLFLAG_RW,
193     &tcp_sad_low_pps, 100,
194     "What is the input pps that below which we do not decay?");
195 #endif
196 uint32_t tcp_ack_war_time_window = 1000;
197 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, ack_war_timewindow,
198     CTLFLAG_RW,
199     &tcp_ack_war_time_window, 1000,
200    "If the tcp_stack does ack-war prevention how many milliseconds are in its time window?");
201 uint32_t tcp_ack_war_cnt = 5;
202 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, ack_war_cnt,
203     CTLFLAG_RW,
204     &tcp_ack_war_cnt, 5,
205    "If the tcp_stack does ack-war prevention how many acks can be sent in its time window?");
206
207 struct rwlock tcp_function_lock;
208
209 static int
210 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
211 {
212         int error, new;
213
214         new = V_tcp_mssdflt;
215         error = sysctl_handle_int(oidp, &new, 0, req);
216         if (error == 0 && req->newptr) {
217                 if (new < TCP_MINMSS)
218                         error = EINVAL;
219                 else
220                         V_tcp_mssdflt = new;
221         }
222         return (error);
223 }
224
225 SYSCTL_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
226     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
227     &VNET_NAME(tcp_mssdflt), 0, &sysctl_net_inet_tcp_mss_check, "I",
228     "Default TCP Maximum Segment Size");
229
230 #ifdef INET6
231 static int
232 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS)
233 {
234         int error, new;
235
236         new = V_tcp_v6mssdflt;
237         error = sysctl_handle_int(oidp, &new, 0, req);
238         if (error == 0 && req->newptr) {
239                 if (new < TCP_MINMSS)
240                         error = EINVAL;
241                 else
242                         V_tcp_v6mssdflt = new;
243         }
244         return (error);
245 }
246
247 SYSCTL_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
248     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
249     &VNET_NAME(tcp_v6mssdflt), 0, &sysctl_net_inet_tcp_mss_v6_check, "I",
250    "Default TCP Maximum Segment Size for IPv6");
251 #endif /* INET6 */
252
253 /*
254  * Minimum MSS we accept and use. This prevents DoS attacks where
255  * we are forced to a ridiculous low MSS like 20 and send hundreds
256  * of packets instead of one. The effect scales with the available
257  * bandwidth and quickly saturates the CPU and network interface
258  * with packet generation and sending. Set to zero to disable MINMSS
259  * checking. This setting prevents us from sending too small packets.
260  */
261 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS;
262 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_VNET | CTLFLAG_RW,
263      &VNET_NAME(tcp_minmss), 0,
264     "Minimum TCP Maximum Segment Size");
265
266 VNET_DEFINE(int, tcp_do_rfc1323) = 1;
267 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_VNET | CTLFLAG_RW,
268     &VNET_NAME(tcp_do_rfc1323), 0,
269     "Enable rfc1323 (high performance TCP) extensions");
270
271 /*
272  * As of June 2021, several TCP stacks violate RFC 7323 from September 2014.
273  * Some stacks negotiate TS, but never send them after connection setup. Some
274  * stacks negotiate TS, but don't send them when sending keep-alive segments.
275  * These include modern widely deployed TCP stacks.
276  * Therefore tolerating violations for now...
277  */
278 VNET_DEFINE(int, tcp_tolerate_missing_ts) = 1;
279 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tolerate_missing_ts, CTLFLAG_VNET | CTLFLAG_RW,
280     &VNET_NAME(tcp_tolerate_missing_ts), 0,
281     "Tolerate missing TCP timestamps");
282
283 VNET_DEFINE(int, tcp_ts_offset_per_conn) = 1;
284 SYSCTL_INT(_net_inet_tcp, OID_AUTO, ts_offset_per_conn, CTLFLAG_VNET | CTLFLAG_RW,
285     &VNET_NAME(tcp_ts_offset_per_conn), 0,
286     "Initialize TCP timestamps per connection instead of per host pair");
287
288 /* How many connections are pacing */
289 static volatile uint32_t number_of_tcp_connections_pacing = 0;
290 static uint32_t shadow_num_connections = 0;
291
292 static int tcp_pacing_limit = 10000;
293 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pacing_limit, CTLFLAG_RW,
294     &tcp_pacing_limit, 1000,
295     "If the TCP stack does pacing, is there a limit (-1 = no, 0 = no pacing N = number of connections)");
296
297 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, pacing_count, CTLFLAG_RD,
298     &shadow_num_connections, 0, "Number of TCP connections being paced");
299
300 static int      tcp_log_debug = 0;
301 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW,
302     &tcp_log_debug, 0, "Log errors caused by incoming TCP segments");
303
304 static int      tcp_tcbhashsize;
305 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
306     &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
307
308 static int      do_tcpdrain = 1;
309 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
310     "Enable tcp_drain routine for extra help when low on mbufs");
311
312 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_VNET | CTLFLAG_RD,
313     &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
314
315 VNET_DEFINE_STATIC(int, icmp_may_rst) = 1;
316 #define V_icmp_may_rst                  VNET(icmp_may_rst)
317 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_VNET | CTLFLAG_RW,
318     &VNET_NAME(icmp_may_rst), 0,
319     "Certain ICMP unreachable messages may abort connections in SYN_SENT");
320
321 VNET_DEFINE_STATIC(int, tcp_isn_reseed_interval) = 0;
322 #define V_tcp_isn_reseed_interval       VNET(tcp_isn_reseed_interval)
323 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_VNET | CTLFLAG_RW,
324     &VNET_NAME(tcp_isn_reseed_interval), 0,
325     "Seconds between reseeding of ISN secret");
326
327 static int      tcp_soreceive_stream;
328 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
329     &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
330
331 VNET_DEFINE(uma_zone_t, sack_hole_zone);
332 #define V_sack_hole_zone                VNET(sack_hole_zone)
333 VNET_DEFINE(uint32_t, tcp_map_entries_limit) = 0;       /* unlimited */
334 static int
335 sysctl_net_inet_tcp_map_limit_check(SYSCTL_HANDLER_ARGS)
336 {
337         int error;
338         uint32_t new;
339
340         new = V_tcp_map_entries_limit;
341         error = sysctl_handle_int(oidp, &new, 0, req);
342         if (error == 0 && req->newptr) {
343                 /* only allow "0" and value > minimum */
344                 if (new > 0 && new < TCP_MIN_MAP_ENTRIES_LIMIT)
345                         error = EINVAL;
346                 else
347                         V_tcp_map_entries_limit = new;
348         }
349         return (error);
350 }
351 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, map_limit,
352     CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
353     &VNET_NAME(tcp_map_entries_limit), 0,
354     &sysctl_net_inet_tcp_map_limit_check, "IU",
355     "Total sendmap entries limit");
356
357 VNET_DEFINE(uint32_t, tcp_map_split_limit) = 0; /* unlimited */
358 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, split_limit, CTLFLAG_VNET | CTLFLAG_RW,
359      &VNET_NAME(tcp_map_split_limit), 0,
360     "Total sendmap split entries limit");
361
362 #ifdef TCP_HHOOK
363 VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]);
364 #endif
365
366 #define TS_OFFSET_SECRET_LENGTH SIPHASH_KEY_LENGTH
367 VNET_DEFINE_STATIC(u_char, ts_offset_secret[TS_OFFSET_SECRET_LENGTH]);
368 #define V_ts_offset_secret      VNET(ts_offset_secret)
369
370 static int      tcp_default_fb_init(struct tcpcb *tp);
371 static void     tcp_default_fb_fini(struct tcpcb *tp, int tcb_is_purged);
372 static int      tcp_default_handoff_ok(struct tcpcb *tp);
373 static struct inpcb *tcp_notify(struct inpcb *, int);
374 static struct inpcb *tcp_mtudisc_notify(struct inpcb *, int);
375 static struct inpcb *tcp_mtudisc(struct inpcb *, int);
376 static char *   tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th,
377                     const void *ip4hdr, const void *ip6hdr);
378
379 static struct tcp_function_block tcp_def_funcblk = {
380         .tfb_tcp_block_name = "freebsd",
381         .tfb_tcp_output = tcp_default_output,
382         .tfb_tcp_do_segment = tcp_do_segment,
383         .tfb_tcp_ctloutput = tcp_default_ctloutput,
384         .tfb_tcp_handoff_ok = tcp_default_handoff_ok,
385         .tfb_tcp_fb_init = tcp_default_fb_init,
386         .tfb_tcp_fb_fini = tcp_default_fb_fini,
387 };
388
389 static int tcp_fb_cnt = 0;
390 struct tcp_funchead t_functions;
391 static struct tcp_function_block *tcp_func_set_ptr = &tcp_def_funcblk;
392
393 void
394 tcp_record_dsack(struct tcpcb *tp, tcp_seq start, tcp_seq end, int tlp)
395 {
396         TCPSTAT_INC(tcps_dsack_count);
397         tp->t_dsack_pack++;
398         if (tlp == 0) {
399                 if (SEQ_GT(end, start)) {
400                         tp->t_dsack_bytes += (end - start);
401                         TCPSTAT_ADD(tcps_dsack_bytes, (end - start));
402                 } else {
403                         tp->t_dsack_tlp_bytes += (start - end);
404                         TCPSTAT_ADD(tcps_dsack_bytes, (start - end));
405                 }
406         } else {
407                 if (SEQ_GT(end, start)) {
408                         tp->t_dsack_bytes += (end - start);
409                         TCPSTAT_ADD(tcps_dsack_tlp_bytes, (end - start));
410                 } else {
411                         tp->t_dsack_tlp_bytes += (start - end);
412                         TCPSTAT_ADD(tcps_dsack_tlp_bytes, (start - end));
413                 }
414         }
415 }
416
417 static struct tcp_function_block *
418 find_tcp_functions_locked(struct tcp_function_set *fs)
419 {
420         struct tcp_function *f;
421         struct tcp_function_block *blk=NULL;
422
423         TAILQ_FOREACH(f, &t_functions, tf_next) {
424                 if (strcmp(f->tf_name, fs->function_set_name) == 0) {
425                         blk = f->tf_fb;
426                         break;
427                 }
428         }
429         return(blk);
430 }
431
432 static struct tcp_function_block *
433 find_tcp_fb_locked(struct tcp_function_block *blk, struct tcp_function **s)
434 {
435         struct tcp_function_block *rblk=NULL;
436         struct tcp_function *f;
437
438         TAILQ_FOREACH(f, &t_functions, tf_next) {
439                 if (f->tf_fb == blk) {
440                         rblk = blk;
441                         if (s) {
442                                 *s = f;
443                         }
444                         break;
445                 }
446         }
447         return (rblk);
448 }
449
450 struct tcp_function_block *
451 find_and_ref_tcp_functions(struct tcp_function_set *fs)
452 {
453         struct tcp_function_block *blk;
454
455         rw_rlock(&tcp_function_lock);
456         blk = find_tcp_functions_locked(fs);
457         if (blk)
458                 refcount_acquire(&blk->tfb_refcnt);
459         rw_runlock(&tcp_function_lock);
460         return(blk);
461 }
462
463 struct tcp_function_block *
464 find_and_ref_tcp_fb(struct tcp_function_block *blk)
465 {
466         struct tcp_function_block *rblk;
467
468         rw_rlock(&tcp_function_lock);
469         rblk = find_tcp_fb_locked(blk, NULL);
470         if (rblk)
471                 refcount_acquire(&rblk->tfb_refcnt);
472         rw_runlock(&tcp_function_lock);
473         return(rblk);
474 }
475
476 /* Find a matching alias for the given tcp_function_block. */
477 int
478 find_tcp_function_alias(struct tcp_function_block *blk,
479     struct tcp_function_set *fs)
480 {
481         struct tcp_function *f;
482         int found;
483
484         found = 0;
485         rw_rlock(&tcp_function_lock);
486         TAILQ_FOREACH(f, &t_functions, tf_next) {
487                 if ((f->tf_fb == blk) &&
488                     (strncmp(f->tf_name, blk->tfb_tcp_block_name,
489                         TCP_FUNCTION_NAME_LEN_MAX) != 0)) {
490                         /* Matching function block with different name. */
491                         strncpy(fs->function_set_name, f->tf_name,
492                             TCP_FUNCTION_NAME_LEN_MAX);
493                         found = 1;
494                         break;
495                 }
496         }
497         /* Null terminate the string appropriately. */
498         if (found) {
499                 fs->function_set_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
500         } else {
501                 fs->function_set_name[0] = '\0';
502         }
503         rw_runlock(&tcp_function_lock);
504         return (found);
505 }
506
507 static struct tcp_function_block *
508 find_and_ref_tcp_default_fb(void)
509 {
510         struct tcp_function_block *rblk;
511
512         rw_rlock(&tcp_function_lock);
513         rblk = tcp_func_set_ptr;
514         refcount_acquire(&rblk->tfb_refcnt);
515         rw_runlock(&tcp_function_lock);
516         return (rblk);
517 }
518
519 void
520 tcp_switch_back_to_default(struct tcpcb *tp)
521 {
522         struct tcp_function_block *tfb;
523
524         KASSERT(tp->t_fb != &tcp_def_funcblk,
525             ("%s: called by the built-in default stack", __func__));
526
527         /*
528          * Release the old stack. This function will either find a new one
529          * or panic.
530          */
531         if (tp->t_fb->tfb_tcp_fb_fini != NULL)
532                 (*tp->t_fb->tfb_tcp_fb_fini)(tp, 0);
533         refcount_release(&tp->t_fb->tfb_refcnt);
534
535         /*
536          * Now, we'll find a new function block to use.
537          * Start by trying the current user-selected
538          * default, unless this stack is the user-selected
539          * default.
540          */
541         tfb = find_and_ref_tcp_default_fb();
542         if (tfb == tp->t_fb) {
543                 refcount_release(&tfb->tfb_refcnt);
544                 tfb = NULL;
545         }
546         /* Does the stack accept this connection? */
547         if (tfb != NULL && tfb->tfb_tcp_handoff_ok != NULL &&
548             (*tfb->tfb_tcp_handoff_ok)(tp)) {
549                 refcount_release(&tfb->tfb_refcnt);
550                 tfb = NULL;
551         }
552         /* Try to use that stack. */
553         if (tfb != NULL) {
554                 /* Initialize the new stack. If it succeeds, we are done. */
555                 tp->t_fb = tfb;
556                 if (tp->t_fb->tfb_tcp_fb_init == NULL ||
557                     (*tp->t_fb->tfb_tcp_fb_init)(tp) == 0)
558                         return;
559
560                 /*
561                  * Initialization failed. Release the reference count on
562                  * the stack.
563                  */
564                 refcount_release(&tfb->tfb_refcnt);
565         }
566
567         /*
568          * If that wasn't feasible, use the built-in default
569          * stack which is not allowed to reject anyone.
570          */
571         tfb = find_and_ref_tcp_fb(&tcp_def_funcblk);
572         if (tfb == NULL) {
573                 /* there always should be a default */
574                 panic("Can't refer to tcp_def_funcblk");
575         }
576         if (tfb->tfb_tcp_handoff_ok != NULL) {
577                 if ((*tfb->tfb_tcp_handoff_ok) (tp)) {
578                         /* The default stack cannot say no */
579                         panic("Default stack rejects a new session?");
580                 }
581         }
582         tp->t_fb = tfb;
583         if (tp->t_fb->tfb_tcp_fb_init != NULL &&
584             (*tp->t_fb->tfb_tcp_fb_init)(tp)) {
585                 /* The default stack cannot fail */
586                 panic("Default stack initialization failed");
587         }
588 }
589
590 static bool
591 tcp_recv_udp_tunneled_packet(struct mbuf *m, int off, struct inpcb *inp,
592     const struct sockaddr *sa, void *ctx)
593 {
594         struct ip *iph;
595 #ifdef INET6
596         struct ip6_hdr *ip6;
597 #endif
598         struct udphdr *uh;
599         struct tcphdr *th;
600         int thlen;
601         uint16_t port;
602
603         TCPSTAT_INC(tcps_tunneled_pkts);
604         if ((m->m_flags & M_PKTHDR) == 0) {
605                 /* Can't handle one that is not a pkt hdr */
606                 TCPSTAT_INC(tcps_tunneled_errs);
607                 goto out;
608         }
609         thlen = sizeof(struct tcphdr);
610         if (m->m_len < off + sizeof(struct udphdr) + thlen &&
611             (m =  m_pullup(m, off + sizeof(struct udphdr) + thlen)) == NULL) {
612                 TCPSTAT_INC(tcps_tunneled_errs);
613                 goto out;
614         }
615         iph = mtod(m, struct ip *);
616         uh = (struct udphdr *)((caddr_t)iph + off);
617         th = (struct tcphdr *)(uh + 1);
618         thlen = th->th_off << 2;
619         if (m->m_len < off + sizeof(struct udphdr) + thlen) {
620                 m =  m_pullup(m, off + sizeof(struct udphdr) + thlen);
621                 if (m == NULL) {
622                         TCPSTAT_INC(tcps_tunneled_errs);
623                         goto out;
624                 } else {
625                         iph = mtod(m, struct ip *);
626                         uh = (struct udphdr *)((caddr_t)iph + off);
627                         th = (struct tcphdr *)(uh + 1);
628                 }
629         }
630         m->m_pkthdr.tcp_tun_port = port = uh->uh_sport;
631         bcopy(th, uh, m->m_len - off);
632         m->m_len -= sizeof(struct udphdr);
633         m->m_pkthdr.len -= sizeof(struct udphdr);
634         /*
635          * We use the same algorithm for
636          * both UDP and TCP for c-sum. So
637          * the code in tcp_input will skip
638          * the checksum. So we do nothing
639          * with the flag (m->m_pkthdr.csum_flags).
640          */
641         switch (iph->ip_v) {
642 #ifdef INET
643         case IPVERSION:
644                 iph->ip_len = htons(ntohs(iph->ip_len) - sizeof(struct udphdr));
645                 tcp_input_with_port(&m, &off, IPPROTO_TCP, port);
646                 break;
647 #endif
648 #ifdef INET6
649         case IPV6_VERSION >> 4:
650                 ip6 = mtod(m, struct ip6_hdr *);
651                 ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) - sizeof(struct udphdr));
652                 tcp6_input_with_port(&m, &off, IPPROTO_TCP, port);
653                 break;
654 #endif
655         default:
656                 goto out;
657                 break;
658         }
659         return (true);
660 out:
661         m_freem(m);
662
663         return (true);
664 }
665
666 static int
667 sysctl_net_inet_default_tcp_functions(SYSCTL_HANDLER_ARGS)
668 {
669         int error=ENOENT;
670         struct tcp_function_set fs;
671         struct tcp_function_block *blk;
672
673         memset(&fs, 0, sizeof(fs));
674         rw_rlock(&tcp_function_lock);
675         blk = find_tcp_fb_locked(tcp_func_set_ptr, NULL);
676         if (blk) {
677                 /* Found him */
678                 strcpy(fs.function_set_name, blk->tfb_tcp_block_name);
679                 fs.pcbcnt = blk->tfb_refcnt;
680         }
681         rw_runlock(&tcp_function_lock);
682         error = sysctl_handle_string(oidp, fs.function_set_name,
683                                      sizeof(fs.function_set_name), req);
684
685         /* Check for error or no change */
686         if (error != 0 || req->newptr == NULL)
687                 return(error);
688
689         rw_wlock(&tcp_function_lock);
690         blk = find_tcp_functions_locked(&fs);
691         if ((blk == NULL) ||
692             (blk->tfb_flags & TCP_FUNC_BEING_REMOVED)) {
693                 error = ENOENT;
694                 goto done;
695         }
696         tcp_func_set_ptr = blk;
697 done:
698         rw_wunlock(&tcp_function_lock);
699         return (error);
700 }
701
702 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_default,
703     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
704     NULL, 0, sysctl_net_inet_default_tcp_functions, "A",
705     "Set/get the default TCP functions");
706
707 static int
708 sysctl_net_inet_list_available(SYSCTL_HANDLER_ARGS)
709 {
710         int error, cnt, linesz;
711         struct tcp_function *f;
712         char *buffer, *cp;
713         size_t bufsz, outsz;
714         bool alias;
715
716         cnt = 0;
717         rw_rlock(&tcp_function_lock);
718         TAILQ_FOREACH(f, &t_functions, tf_next) {
719                 cnt++;
720         }
721         rw_runlock(&tcp_function_lock);
722
723         bufsz = (cnt+2) * ((TCP_FUNCTION_NAME_LEN_MAX * 2) + 13) + 1;
724         buffer = malloc(bufsz, M_TEMP, M_WAITOK);
725
726         error = 0;
727         cp = buffer;
728
729         linesz = snprintf(cp, bufsz, "\n%-32s%c %-32s %s\n", "Stack", 'D',
730             "Alias", "PCB count");
731         cp += linesz;
732         bufsz -= linesz;
733         outsz = linesz;
734
735         rw_rlock(&tcp_function_lock);
736         TAILQ_FOREACH(f, &t_functions, tf_next) {
737                 alias = (f->tf_name != f->tf_fb->tfb_tcp_block_name);
738                 linesz = snprintf(cp, bufsz, "%-32s%c %-32s %u\n",
739                     f->tf_fb->tfb_tcp_block_name,
740                     (f->tf_fb == tcp_func_set_ptr) ? '*' : ' ',
741                     alias ? f->tf_name : "-",
742                     f->tf_fb->tfb_refcnt);
743                 if (linesz >= bufsz) {
744                         error = EOVERFLOW;
745                         break;
746                 }
747                 cp += linesz;
748                 bufsz -= linesz;
749                 outsz += linesz;
750         }
751         rw_runlock(&tcp_function_lock);
752         if (error == 0)
753                 error = sysctl_handle_string(oidp, buffer, outsz + 1, req);
754         free(buffer, M_TEMP);
755         return (error);
756 }
757
758 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_available,
759     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT,
760     NULL, 0, sysctl_net_inet_list_available, "A",
761     "list available TCP Function sets");
762
763 VNET_DEFINE(int, tcp_udp_tunneling_port) = TCP_TUNNELING_PORT_DEFAULT;
764
765 #ifdef INET
766 VNET_DEFINE(struct socket *, udp4_tun_socket) = NULL;
767 #define V_udp4_tun_socket       VNET(udp4_tun_socket)
768 #endif
769 #ifdef INET6
770 VNET_DEFINE(struct socket *, udp6_tun_socket) = NULL;
771 #define V_udp6_tun_socket       VNET(udp6_tun_socket)
772 #endif
773
774 static void
775 tcp_over_udp_stop(void)
776 {
777         /*
778          * This function assumes sysctl caller holds inp_rinfo_lock()
779          * for writing!
780          */
781 #ifdef INET
782         if (V_udp4_tun_socket != NULL) {
783                 soclose(V_udp4_tun_socket);
784                 V_udp4_tun_socket = NULL;
785         }
786 #endif
787 #ifdef INET6
788         if (V_udp6_tun_socket != NULL) {
789                 soclose(V_udp6_tun_socket);
790                 V_udp6_tun_socket = NULL;
791         }
792 #endif
793 }
794
795 static int
796 tcp_over_udp_start(void)
797 {
798         uint16_t port;
799         int ret;
800 #ifdef INET
801         struct sockaddr_in sin;
802 #endif
803 #ifdef INET6
804         struct sockaddr_in6 sin6;
805 #endif
806         /*
807          * This function assumes sysctl caller holds inp_info_rlock()
808          * for writing!
809          */
810         port = V_tcp_udp_tunneling_port;
811         if (ntohs(port) == 0) {
812                 /* Must have a port set */
813                 return (EINVAL);
814         }
815 #ifdef INET
816         if (V_udp4_tun_socket != NULL) {
817                 /* Already running -- must stop first */
818                 return (EALREADY);
819         }
820 #endif
821 #ifdef INET6
822         if (V_udp6_tun_socket != NULL) {
823                 /* Already running -- must stop first */
824                 return (EALREADY);
825         }
826 #endif
827 #ifdef INET
828         if ((ret = socreate(PF_INET, &V_udp4_tun_socket,
829             SOCK_DGRAM, IPPROTO_UDP,
830             curthread->td_ucred, curthread))) {
831                 tcp_over_udp_stop();
832                 return (ret);
833         }
834         /* Call the special UDP hook. */
835         if ((ret = udp_set_kernel_tunneling(V_udp4_tun_socket,
836             tcp_recv_udp_tunneled_packet,
837             tcp_ctlinput_viaudp,
838             NULL))) {
839                 tcp_over_udp_stop();
840                 return (ret);
841         }
842         /* Ok, we have a socket, bind it to the port. */
843         memset(&sin, 0, sizeof(struct sockaddr_in));
844         sin.sin_len = sizeof(struct sockaddr_in);
845         sin.sin_family = AF_INET;
846         sin.sin_port = htons(port);
847         if ((ret = sobind(V_udp4_tun_socket,
848             (struct sockaddr *)&sin, curthread))) {
849                 tcp_over_udp_stop();
850                 return (ret);
851         }
852 #endif
853 #ifdef INET6
854         if ((ret = socreate(PF_INET6, &V_udp6_tun_socket,
855             SOCK_DGRAM, IPPROTO_UDP,
856             curthread->td_ucred, curthread))) {
857                 tcp_over_udp_stop();
858                 return (ret);
859         }
860         /* Call the special UDP hook. */
861         if ((ret = udp_set_kernel_tunneling(V_udp6_tun_socket,
862             tcp_recv_udp_tunneled_packet,
863             tcp6_ctlinput_viaudp,
864             NULL))) {
865                 tcp_over_udp_stop();
866                 return (ret);
867         }
868         /* Ok, we have a socket, bind it to the port. */
869         memset(&sin6, 0, sizeof(struct sockaddr_in6));
870         sin6.sin6_len = sizeof(struct sockaddr_in6);
871         sin6.sin6_family = AF_INET6;
872         sin6.sin6_port = htons(port);
873         if ((ret = sobind(V_udp6_tun_socket,
874             (struct sockaddr *)&sin6, curthread))) {
875                 tcp_over_udp_stop();
876                 return (ret);
877         }
878 #endif
879         return (0);
880 }
881
882 static int
883 sysctl_net_inet_tcp_udp_tunneling_port_check(SYSCTL_HANDLER_ARGS)
884 {
885         int error;
886         uint32_t old, new;
887
888         old = V_tcp_udp_tunneling_port;
889         new = old;
890         error = sysctl_handle_int(oidp, &new, 0, req);
891         if ((error == 0) &&
892             (req->newptr != NULL)) {
893                 if ((new < TCP_TUNNELING_PORT_MIN) ||
894                     (new > TCP_TUNNELING_PORT_MAX)) {
895                         error = EINVAL;
896                 } else {
897                         V_tcp_udp_tunneling_port = new;
898                         if (old != 0) {
899                                 tcp_over_udp_stop();
900                         }
901                         if (new != 0) {
902                                 error = tcp_over_udp_start();
903                         }
904                 }
905         }
906         return (error);
907 }
908
909 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, udp_tunneling_port,
910     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
911     &VNET_NAME(tcp_udp_tunneling_port),
912     0, &sysctl_net_inet_tcp_udp_tunneling_port_check, "IU",
913     "Tunneling port for tcp over udp");
914
915 VNET_DEFINE(int, tcp_udp_tunneling_overhead) = TCP_TUNNELING_OVERHEAD_DEFAULT;
916
917 static int
918 sysctl_net_inet_tcp_udp_tunneling_overhead_check(SYSCTL_HANDLER_ARGS)
919 {
920         int error, new;
921
922         new = V_tcp_udp_tunneling_overhead;
923         error = sysctl_handle_int(oidp, &new, 0, req);
924         if (error == 0 && req->newptr) {
925                 if ((new < TCP_TUNNELING_OVERHEAD_MIN) ||
926                     (new > TCP_TUNNELING_OVERHEAD_MAX))
927                         error = EINVAL;
928                 else
929                         V_tcp_udp_tunneling_overhead = new;
930         }
931         return (error);
932 }
933
934 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, udp_tunneling_overhead,
935     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
936     &VNET_NAME(tcp_udp_tunneling_overhead),
937     0, &sysctl_net_inet_tcp_udp_tunneling_overhead_check, "IU",
938     "MSS reduction when using tcp over udp");
939
940 /*
941  * Exports one (struct tcp_function_info) for each alias/name.
942  */
943 static int
944 sysctl_net_inet_list_func_info(SYSCTL_HANDLER_ARGS)
945 {
946         int cnt, error;
947         struct tcp_function *f;
948         struct tcp_function_info tfi;
949
950         /*
951          * We don't allow writes.
952          */
953         if (req->newptr != NULL)
954                 return (EINVAL);
955
956         /*
957          * Wire the old buffer so we can directly copy the functions to
958          * user space without dropping the lock.
959          */
960         if (req->oldptr != NULL) {
961                 error = sysctl_wire_old_buffer(req, 0);
962                 if (error)
963                         return (error);
964         }
965
966         /*
967          * Walk the list and copy out matching entries. If INVARIANTS
968          * is compiled in, also walk the list to verify the length of
969          * the list matches what we have recorded.
970          */
971         rw_rlock(&tcp_function_lock);
972
973         cnt = 0;
974 #ifndef INVARIANTS
975         if (req->oldptr == NULL) {
976                 cnt = tcp_fb_cnt;
977                 goto skip_loop;
978         }
979 #endif
980         TAILQ_FOREACH(f, &t_functions, tf_next) {
981 #ifdef INVARIANTS
982                 cnt++;
983 #endif
984                 if (req->oldptr != NULL) {
985                         bzero(&tfi, sizeof(tfi));
986                         tfi.tfi_refcnt = f->tf_fb->tfb_refcnt;
987                         tfi.tfi_id = f->tf_fb->tfb_id;
988                         (void)strlcpy(tfi.tfi_alias, f->tf_name,
989                             sizeof(tfi.tfi_alias));
990                         (void)strlcpy(tfi.tfi_name,
991                             f->tf_fb->tfb_tcp_block_name, sizeof(tfi.tfi_name));
992                         error = SYSCTL_OUT(req, &tfi, sizeof(tfi));
993                         /*
994                          * Don't stop on error, as that is the
995                          * mechanism we use to accumulate length
996                          * information if the buffer was too short.
997                          */
998                 }
999         }
1000         KASSERT(cnt == tcp_fb_cnt,
1001             ("%s: cnt (%d) != tcp_fb_cnt (%d)", __func__, cnt, tcp_fb_cnt));
1002 #ifndef INVARIANTS
1003 skip_loop:
1004 #endif
1005         rw_runlock(&tcp_function_lock);
1006         if (req->oldptr == NULL)
1007                 error = SYSCTL_OUT(req, NULL,
1008                     (cnt + 1) * sizeof(struct tcp_function_info));
1009
1010         return (error);
1011 }
1012
1013 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, function_info,
1014             CTLTYPE_OPAQUE | CTLFLAG_SKIP | CTLFLAG_RD | CTLFLAG_MPSAFE,
1015             NULL, 0, sysctl_net_inet_list_func_info, "S,tcp_function_info",
1016             "List TCP function block name-to-ID mappings");
1017
1018 /*
1019  * tfb_tcp_handoff_ok() function for the default stack.
1020  * Note that we'll basically try to take all comers.
1021  */
1022 static int
1023 tcp_default_handoff_ok(struct tcpcb *tp)
1024 {
1025
1026         return (0);
1027 }
1028
1029 /*
1030  * tfb_tcp_fb_init() function for the default stack.
1031  *
1032  * This handles making sure we have appropriate timers set if you are
1033  * transitioning a socket that has some amount of setup done.
1034  *
1035  * The init() fuction from the default can *never* return non-zero i.e.
1036  * it is required to always succeed since it is the stack of last resort!
1037  */
1038 static int
1039 tcp_default_fb_init(struct tcpcb *tp)
1040 {
1041
1042         struct socket *so;
1043
1044         INP_WLOCK_ASSERT(tp->t_inpcb);
1045
1046         KASSERT(tp->t_state >= 0 && tp->t_state < TCPS_TIME_WAIT,
1047             ("%s: connection %p in unexpected state %d", __func__, tp,
1048             tp->t_state));
1049
1050         /*
1051          * Nothing to do for ESTABLISHED or LISTEN states. And, we don't
1052          * know what to do for unexpected states (which includes TIME_WAIT).
1053          */
1054         if (tp->t_state <= TCPS_LISTEN || tp->t_state >= TCPS_TIME_WAIT)
1055                 return (0);
1056
1057         /*
1058          * Make sure some kind of transmission timer is set if there is
1059          * outstanding data.
1060          */
1061         so = tp->t_inpcb->inp_socket;
1062         if ((!TCPS_HAVEESTABLISHED(tp->t_state) || sbavail(&so->so_snd) ||
1063             tp->snd_una != tp->snd_max) && !(tcp_timer_active(tp, TT_REXMT) ||
1064             tcp_timer_active(tp, TT_PERSIST))) {
1065                 /*
1066                  * If the session has established and it looks like it should
1067                  * be in the persist state, set the persist timer. Otherwise,
1068                  * set the retransmit timer.
1069                  */
1070                 if (TCPS_HAVEESTABLISHED(tp->t_state) && tp->snd_wnd == 0 &&
1071                     (int32_t)(tp->snd_nxt - tp->snd_una) <
1072                     (int32_t)sbavail(&so->so_snd))
1073                         tcp_setpersist(tp);
1074                 else
1075                         tcp_timer_activate(tp, TT_REXMT, tp->t_rxtcur);
1076         }
1077
1078         /* All non-embryonic sessions get a keepalive timer. */
1079         if (!tcp_timer_active(tp, TT_KEEP))
1080                 tcp_timer_activate(tp, TT_KEEP,
1081                     TCPS_HAVEESTABLISHED(tp->t_state) ? TP_KEEPIDLE(tp) :
1082                     TP_KEEPINIT(tp));
1083
1084         /*
1085          * Make sure critical variables are initialized
1086          * if transitioning while in Recovery.
1087          */
1088         if IN_FASTRECOVERY(tp->t_flags) {
1089                 if (tp->sackhint.recover_fs == 0)
1090                         tp->sackhint.recover_fs = max(1,
1091                             tp->snd_nxt - tp->snd_una);
1092         }
1093
1094         return (0);
1095 }
1096
1097 /*
1098  * tfb_tcp_fb_fini() function for the default stack.
1099  *
1100  * This changes state as necessary (or prudent) to prepare for another stack
1101  * to assume responsibility for the connection.
1102  */
1103 static void
1104 tcp_default_fb_fini(struct tcpcb *tp, int tcb_is_purged)
1105 {
1106
1107         INP_WLOCK_ASSERT(tp->t_inpcb);
1108         return;
1109 }
1110
1111 /*
1112  * Target size of TCP PCB hash tables. Must be a power of two.
1113  *
1114  * Note that this can be overridden by the kernel environment
1115  * variable net.inet.tcp.tcbhashsize
1116  */
1117 #ifndef TCBHASHSIZE
1118 #define TCBHASHSIZE     0
1119 #endif
1120
1121 /*
1122  * XXX
1123  * Callouts should be moved into struct tcp directly.  They are currently
1124  * separate because the tcpcb structure is exported to userland for sysctl
1125  * parsing purposes, which do not know about callouts.
1126  */
1127 struct tcpcb_mem {
1128         struct  tcpcb           tcb;
1129         struct  tcp_timer       tt;
1130         struct  cc_var          ccv;
1131 #ifdef TCP_HHOOK
1132         struct  osd             osd;
1133 #endif
1134 };
1135
1136 VNET_DEFINE_STATIC(uma_zone_t, tcpcb_zone);
1137 #define V_tcpcb_zone                    VNET(tcpcb_zone)
1138
1139 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
1140 MALLOC_DEFINE(M_TCPFUNCTIONS, "tcpfunc", "TCP function set memory");
1141
1142 static struct mtx isn_mtx;
1143
1144 #define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF)
1145 #define ISN_LOCK()      mtx_lock(&isn_mtx)
1146 #define ISN_UNLOCK()    mtx_unlock(&isn_mtx)
1147
1148 INPCBSTORAGE_DEFINE(tcpcbstor, "tcpinp", "tcp_inpcb", "tcp", "tcphash");
1149
1150 /*
1151  * Take a value and get the next power of 2 that doesn't overflow.
1152  * Used to size the tcp_inpcb hash buckets.
1153  */
1154 static int
1155 maketcp_hashsize(int size)
1156 {
1157         int hashsize;
1158
1159         /*
1160          * auto tune.
1161          * get the next power of 2 higher than maxsockets.
1162          */
1163         hashsize = 1 << fls(size);
1164         /* catch overflow, and just go one power of 2 smaller */
1165         if (hashsize < size) {
1166                 hashsize = 1 << (fls(size) - 1);
1167         }
1168         return (hashsize);
1169 }
1170
1171 static volatile int next_tcp_stack_id = 1;
1172
1173 /*
1174  * Register a TCP function block with the name provided in the names
1175  * array.  (Note that this function does NOT automatically register
1176  * blk->tfb_tcp_block_name as a stack name.  Therefore, you should
1177  * explicitly include blk->tfb_tcp_block_name in the list of names if
1178  * you wish to register the stack with that name.)
1179  *
1180  * Either all name registrations will succeed or all will fail.  If
1181  * a name registration fails, the function will update the num_names
1182  * argument to point to the array index of the name that encountered
1183  * the failure.
1184  *
1185  * Returns 0 on success, or an error code on failure.
1186  */
1187 int
1188 register_tcp_functions_as_names(struct tcp_function_block *blk, int wait,
1189     const char *names[], int *num_names)
1190 {
1191         struct tcp_function *n;
1192         struct tcp_function_set fs;
1193         int error, i;
1194
1195         KASSERT(names != NULL && *num_names > 0,
1196             ("%s: Called with 0-length name list", __func__));
1197         KASSERT(names != NULL, ("%s: Called with NULL name list", __func__));
1198         KASSERT(rw_initialized(&tcp_function_lock),
1199             ("%s: called too early", __func__));
1200
1201         if ((blk->tfb_tcp_output == NULL) ||
1202             (blk->tfb_tcp_do_segment == NULL) ||
1203             (blk->tfb_tcp_ctloutput == NULL) ||
1204             (strlen(blk->tfb_tcp_block_name) == 0)) {
1205                 /*
1206                  * These functions are required and you
1207                  * need a name.
1208                  */
1209                 *num_names = 0;
1210                 return (EINVAL);
1211         }
1212         if (blk->tfb_tcp_timer_stop_all ||
1213             blk->tfb_tcp_timer_activate ||
1214             blk->tfb_tcp_timer_active ||
1215             blk->tfb_tcp_timer_stop) {
1216                 /*
1217                  * If you define one timer function you
1218                  * must have them all.
1219                  */
1220                 if ((blk->tfb_tcp_timer_stop_all == NULL) ||
1221                     (blk->tfb_tcp_timer_activate == NULL) ||
1222                     (blk->tfb_tcp_timer_active == NULL) ||
1223                     (blk->tfb_tcp_timer_stop == NULL)) {
1224                         *num_names = 0;
1225                         return (EINVAL);
1226                 }
1227         }
1228
1229         if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
1230                 *num_names = 0;
1231                 return (EINVAL);
1232         }
1233
1234         refcount_init(&blk->tfb_refcnt, 0);
1235         blk->tfb_id = atomic_fetchadd_int(&next_tcp_stack_id, 1);
1236         for (i = 0; i < *num_names; i++) {
1237                 n = malloc(sizeof(struct tcp_function), M_TCPFUNCTIONS, wait);
1238                 if (n == NULL) {
1239                         error = ENOMEM;
1240                         goto cleanup;
1241                 }
1242                 n->tf_fb = blk;
1243
1244                 (void)strlcpy(fs.function_set_name, names[i],
1245                     sizeof(fs.function_set_name));
1246                 rw_wlock(&tcp_function_lock);
1247                 if (find_tcp_functions_locked(&fs) != NULL) {
1248                         /* Duplicate name space not allowed */
1249                         rw_wunlock(&tcp_function_lock);
1250                         free(n, M_TCPFUNCTIONS);
1251                         error = EALREADY;
1252                         goto cleanup;
1253                 }
1254                 (void)strlcpy(n->tf_name, names[i], sizeof(n->tf_name));
1255                 TAILQ_INSERT_TAIL(&t_functions, n, tf_next);
1256                 tcp_fb_cnt++;
1257                 rw_wunlock(&tcp_function_lock);
1258         }
1259         return(0);
1260
1261 cleanup:
1262         /*
1263          * Deregister the names we just added. Because registration failed
1264          * for names[i], we don't need to deregister that name.
1265          */
1266         *num_names = i;
1267         rw_wlock(&tcp_function_lock);
1268         while (--i >= 0) {
1269                 TAILQ_FOREACH(n, &t_functions, tf_next) {
1270                         if (!strncmp(n->tf_name, names[i],
1271                             TCP_FUNCTION_NAME_LEN_MAX)) {
1272                                 TAILQ_REMOVE(&t_functions, n, tf_next);
1273                                 tcp_fb_cnt--;
1274                                 n->tf_fb = NULL;
1275                                 free(n, M_TCPFUNCTIONS);
1276                                 break;
1277                         }
1278                 }
1279         }
1280         rw_wunlock(&tcp_function_lock);
1281         return (error);
1282 }
1283
1284 /*
1285  * Register a TCP function block using the name provided in the name
1286  * argument.
1287  *
1288  * Returns 0 on success, or an error code on failure.
1289  */
1290 int
1291 register_tcp_functions_as_name(struct tcp_function_block *blk, const char *name,
1292     int wait)
1293 {
1294         const char *name_list[1];
1295         int num_names, rv;
1296
1297         num_names = 1;
1298         if (name != NULL)
1299                 name_list[0] = name;
1300         else
1301                 name_list[0] = blk->tfb_tcp_block_name;
1302         rv = register_tcp_functions_as_names(blk, wait, name_list, &num_names);
1303         return (rv);
1304 }
1305
1306 /*
1307  * Register a TCP function block using the name defined in
1308  * blk->tfb_tcp_block_name.
1309  *
1310  * Returns 0 on success, or an error code on failure.
1311  */
1312 int
1313 register_tcp_functions(struct tcp_function_block *blk, int wait)
1314 {
1315
1316         return (register_tcp_functions_as_name(blk, NULL, wait));
1317 }
1318
1319 /*
1320  * Deregister all names associated with a function block. This
1321  * functionally removes the function block from use within the system.
1322  *
1323  * When called with a true quiesce argument, mark the function block
1324  * as being removed so no more stacks will use it and determine
1325  * whether the removal would succeed.
1326  *
1327  * When called with a false quiesce argument, actually attempt the
1328  * removal.
1329  *
1330  * When called with a force argument, attempt to switch all TCBs to
1331  * use the default stack instead of returning EBUSY.
1332  *
1333  * Returns 0 on success (or if the removal would succeed, or an error
1334  * code on failure.
1335  */
1336 int
1337 deregister_tcp_functions(struct tcp_function_block *blk, bool quiesce,
1338     bool force)
1339 {
1340         struct tcp_function *f;
1341
1342         if (blk == &tcp_def_funcblk) {
1343                 /* You can't un-register the default */
1344                 return (EPERM);
1345         }
1346         rw_wlock(&tcp_function_lock);
1347         if (blk == tcp_func_set_ptr) {
1348                 /* You can't free the current default */
1349                 rw_wunlock(&tcp_function_lock);
1350                 return (EBUSY);
1351         }
1352         /* Mark the block so no more stacks can use it. */
1353         blk->tfb_flags |= TCP_FUNC_BEING_REMOVED;
1354         /*
1355          * If TCBs are still attached to the stack, attempt to switch them
1356          * to the default stack.
1357          */
1358         if (force && blk->tfb_refcnt) {
1359                 struct inpcb_iterator inpi = INP_ALL_ITERATOR(&V_tcbinfo,
1360                     INPLOOKUP_WLOCKPCB);
1361                 struct inpcb *inp;
1362                 struct tcpcb *tp;
1363                 VNET_ITERATOR_DECL(vnet_iter);
1364
1365                 rw_wunlock(&tcp_function_lock);
1366
1367                 VNET_LIST_RLOCK();
1368                 VNET_FOREACH(vnet_iter) {
1369                         CURVNET_SET(vnet_iter);
1370                         while ((inp = inp_next(&inpi)) != NULL) {
1371                                 if (inp->inp_flags & INP_TIMEWAIT)
1372                                         continue;
1373                                 tp = intotcpcb(inp);
1374                                 if (tp == NULL || tp->t_fb != blk)
1375                                         continue;
1376                                 tcp_switch_back_to_default(tp);
1377                         }
1378                         CURVNET_RESTORE();
1379                 }
1380                 VNET_LIST_RUNLOCK();
1381
1382                 rw_wlock(&tcp_function_lock);
1383         }
1384         if (blk->tfb_refcnt) {
1385                 /* TCBs still attached. */
1386                 rw_wunlock(&tcp_function_lock);
1387                 return (EBUSY);
1388         }
1389         if (quiesce) {
1390                 /* Skip removal. */
1391                 rw_wunlock(&tcp_function_lock);
1392                 return (0);
1393         }
1394         /* Remove any function names that map to this function block. */
1395         while (find_tcp_fb_locked(blk, &f) != NULL) {
1396                 TAILQ_REMOVE(&t_functions, f, tf_next);
1397                 tcp_fb_cnt--;
1398                 f->tf_fb = NULL;
1399                 free(f, M_TCPFUNCTIONS);
1400         }
1401         rw_wunlock(&tcp_function_lock);
1402         return (0);
1403 }
1404
1405 static void
1406 tcp_drain(void)
1407 {
1408         struct epoch_tracker et;
1409         VNET_ITERATOR_DECL(vnet_iter);
1410
1411         if (!do_tcpdrain)
1412                 return;
1413
1414         NET_EPOCH_ENTER(et);
1415         VNET_LIST_RLOCK_NOSLEEP();
1416         VNET_FOREACH(vnet_iter) {
1417                 CURVNET_SET(vnet_iter);
1418                 struct inpcb_iterator inpi = INP_ALL_ITERATOR(&V_tcbinfo,
1419                     INPLOOKUP_WLOCKPCB);
1420                 struct inpcb *inpb;
1421                 struct tcpcb *tcpb;
1422
1423         /*
1424          * Walk the tcpbs, if existing, and flush the reassembly queue,
1425          * if there is one...
1426          * XXX: The "Net/3" implementation doesn't imply that the TCP
1427          *      reassembly queue should be flushed, but in a situation
1428          *      where we're really low on mbufs, this is potentially
1429          *      useful.
1430          */
1431                 while ((inpb = inp_next(&inpi)) != NULL) {
1432                         if (inpb->inp_flags & INP_TIMEWAIT)
1433                                 continue;
1434                         if ((tcpb = intotcpcb(inpb)) != NULL) {
1435                                 tcp_reass_flush(tcpb);
1436                                 tcp_clean_sackreport(tcpb);
1437 #ifdef TCP_BLACKBOX
1438                                 tcp_log_drain(tcpb);
1439 #endif
1440 #ifdef TCPPCAP
1441                                 if (tcp_pcap_aggressive_free) {
1442                                         /* Free the TCP PCAP queues. */
1443                                         tcp_pcap_drain(&(tcpb->t_inpkts));
1444                                         tcp_pcap_drain(&(tcpb->t_outpkts));
1445                                 }
1446 #endif
1447                         }
1448                 }
1449                 CURVNET_RESTORE();
1450         }
1451         VNET_LIST_RUNLOCK_NOSLEEP();
1452         NET_EPOCH_EXIT(et);
1453 }
1454
1455 static void
1456 tcp_vnet_init(void *arg __unused)
1457 {
1458
1459 #ifdef TCP_HHOOK
1460         if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN,
1461             &V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
1462                 printf("%s: WARNING: unable to register helper hook\n", __func__);
1463         if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT,
1464             &V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
1465                 printf("%s: WARNING: unable to register helper hook\n", __func__);
1466 #endif
1467 #ifdef STATS
1468         if (tcp_stats_init())
1469                 printf("%s: WARNING: unable to initialise TCP stats\n",
1470                     __func__);
1471 #endif
1472         in_pcbinfo_init(&V_tcbinfo, &tcpcbstor, tcp_tcbhashsize,
1473             tcp_tcbhashsize);
1474
1475         /*
1476          * These have to be type stable for the benefit of the timers.
1477          */
1478         V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
1479             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
1480         uma_zone_set_max(V_tcpcb_zone, maxsockets);
1481         uma_zone_set_warning(V_tcpcb_zone, "kern.ipc.maxsockets limit reached");
1482
1483         tcp_tw_init();
1484         syncache_init();
1485         tcp_hc_init();
1486
1487         TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
1488         V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
1489             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
1490
1491         tcp_fastopen_init();
1492
1493         COUNTER_ARRAY_ALLOC(V_tcps_states, TCP_NSTATES, M_WAITOK);
1494         VNET_PCPUSTAT_ALLOC(tcpstat, M_WAITOK);
1495
1496         V_tcp_msl = TCPTV_MSL;
1497 }
1498 VNET_SYSINIT(tcp_vnet_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
1499     tcp_vnet_init, NULL);
1500
1501 static void
1502 tcp_init(void *arg __unused)
1503 {
1504         const char *tcbhash_tuneable;
1505         int hashsize;
1506
1507         tcp_reass_global_init();
1508
1509         /* XXX virtualize those below? */
1510         tcp_delacktime = TCPTV_DELACK;
1511         tcp_keepinit = TCPTV_KEEP_INIT;
1512         tcp_keepidle = TCPTV_KEEP_IDLE;
1513         tcp_keepintvl = TCPTV_KEEPINTVL;
1514         tcp_maxpersistidle = TCPTV_KEEP_IDLE;
1515         tcp_rexmit_initial = TCPTV_RTOBASE;
1516         if (tcp_rexmit_initial < 1)
1517                 tcp_rexmit_initial = 1;
1518         tcp_rexmit_min = TCPTV_MIN;
1519         if (tcp_rexmit_min < 1)
1520                 tcp_rexmit_min = 1;
1521         tcp_persmin = TCPTV_PERSMIN;
1522         tcp_persmax = TCPTV_PERSMAX;
1523         tcp_rexmit_slop = TCPTV_CPU_VAR;
1524         tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
1525
1526         /* Setup the tcp function block list */
1527         TAILQ_INIT(&t_functions);
1528         rw_init(&tcp_function_lock, "tcp_func_lock");
1529         register_tcp_functions(&tcp_def_funcblk, M_WAITOK);
1530 #ifdef TCP_BLACKBOX
1531         /* Initialize the TCP logging data. */
1532         tcp_log_init();
1533 #endif
1534         arc4rand(&V_ts_offset_secret, sizeof(V_ts_offset_secret), 0);
1535
1536         if (tcp_soreceive_stream) {
1537 #ifdef INET
1538                 tcp_protosw.pr_soreceive = soreceive_stream;
1539 #endif
1540 #ifdef INET6
1541                 tcp6_protosw.pr_soreceive = soreceive_stream;
1542 #endif /* INET6 */
1543         }
1544
1545 #ifdef INET6
1546         max_protohdr_grow(sizeof(struct ip6_hdr) + sizeof(struct tcphdr));
1547 #else /* INET6 */
1548         max_protohdr_grow(sizeof(struct tcpiphdr));
1549 #endif /* INET6 */
1550
1551         ISN_LOCK_INIT();
1552         EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
1553                 SHUTDOWN_PRI_DEFAULT);
1554         EVENTHANDLER_REGISTER(vm_lowmem, tcp_drain, NULL, LOWMEM_PRI_DEFAULT);
1555         EVENTHANDLER_REGISTER(mbuf_lowmem, tcp_drain, NULL, LOWMEM_PRI_DEFAULT);
1556
1557         tcp_inp_lro_direct_queue = counter_u64_alloc(M_WAITOK);
1558         tcp_inp_lro_wokeup_queue = counter_u64_alloc(M_WAITOK);
1559         tcp_inp_lro_compressed = counter_u64_alloc(M_WAITOK);
1560         tcp_inp_lro_locks_taken = counter_u64_alloc(M_WAITOK);
1561         tcp_extra_mbuf = counter_u64_alloc(M_WAITOK);
1562         tcp_would_have_but = counter_u64_alloc(M_WAITOK);
1563         tcp_comp_total = counter_u64_alloc(M_WAITOK);
1564         tcp_uncomp_total = counter_u64_alloc(M_WAITOK);
1565         tcp_bad_csums = counter_u64_alloc(M_WAITOK);
1566 #ifdef TCPPCAP
1567         tcp_pcap_init();
1568 #endif
1569
1570         hashsize = TCBHASHSIZE;
1571         tcbhash_tuneable = "net.inet.tcp.tcbhashsize";
1572         TUNABLE_INT_FETCH(tcbhash_tuneable, &hashsize);
1573         if (hashsize == 0) {
1574                 /*
1575                  * Auto tune the hash size based on maxsockets.
1576                  * A perfect hash would have a 1:1 mapping
1577                  * (hashsize = maxsockets) however it's been
1578                  * suggested that O(2) average is better.
1579                  */
1580                 hashsize = maketcp_hashsize(maxsockets / 4);
1581                 /*
1582                  * Our historical default is 512,
1583                  * do not autotune lower than this.
1584                  */
1585                 if (hashsize < 512)
1586                         hashsize = 512;
1587                 if (bootverbose)
1588                         printf("%s: %s auto tuned to %d\n", __func__,
1589                             tcbhash_tuneable, hashsize);
1590         }
1591         /*
1592          * We require a hashsize to be a power of two.
1593          * Previously if it was not a power of two we would just reset it
1594          * back to 512, which could be a nasty surprise if you did not notice
1595          * the error message.
1596          * Instead what we do is clip it to the closest power of two lower
1597          * than the specified hash value.
1598          */
1599         if (!powerof2(hashsize)) {
1600                 int oldhashsize = hashsize;
1601
1602                 hashsize = maketcp_hashsize(hashsize);
1603                 /* prevent absurdly low value */
1604                 if (hashsize < 16)
1605                         hashsize = 16;
1606                 printf("%s: WARNING: TCB hash size not a power of 2, "
1607                     "clipped from %d to %d.\n", __func__, oldhashsize,
1608                     hashsize);
1609         }
1610         tcp_tcbhashsize = hashsize;
1611
1612 #ifdef INET
1613         IPPROTO_REGISTER(IPPROTO_TCP, tcp_input, tcp_ctlinput);
1614 #endif
1615 #ifdef INET6
1616         IP6PROTO_REGISTER(IPPROTO_TCP, tcp6_input, tcp6_ctlinput);
1617 #endif
1618 }
1619 SYSINIT(tcp_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, tcp_init, NULL);
1620
1621 #ifdef VIMAGE
1622 static void
1623 tcp_destroy(void *unused __unused)
1624 {
1625         int n;
1626 #ifdef TCP_HHOOK
1627         int error;
1628 #endif
1629
1630         /*
1631          * All our processes are gone, all our sockets should be cleaned
1632          * up, which means, we should be past the tcp_discardcb() calls.
1633          * Sleep to let all tcpcb timers really disappear and cleanup.
1634          */
1635         for (;;) {
1636                 INP_INFO_WLOCK(&V_tcbinfo);
1637                 n = V_tcbinfo.ipi_count;
1638                 INP_INFO_WUNLOCK(&V_tcbinfo);
1639                 if (n == 0)
1640                         break;
1641                 pause("tcpdes", hz / 10);
1642         }
1643         tcp_hc_destroy();
1644         syncache_destroy();
1645         tcp_tw_destroy();
1646         in_pcbinfo_destroy(&V_tcbinfo);
1647         /* tcp_discardcb() clears the sack_holes up. */
1648         uma_zdestroy(V_sack_hole_zone);
1649         uma_zdestroy(V_tcpcb_zone);
1650
1651         /*
1652          * Cannot free the zone until all tcpcbs are released as we attach
1653          * the allocations to them.
1654          */
1655         tcp_fastopen_destroy();
1656
1657         COUNTER_ARRAY_FREE(V_tcps_states, TCP_NSTATES);
1658         VNET_PCPUSTAT_FREE(tcpstat);
1659
1660 #ifdef TCP_HHOOK
1661         error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_IN]);
1662         if (error != 0) {
1663                 printf("%s: WARNING: unable to deregister helper hook "
1664                     "type=%d, id=%d: error %d returned\n", __func__,
1665                     HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN, error);
1666         }
1667         error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_OUT]);
1668         if (error != 0) {
1669                 printf("%s: WARNING: unable to deregister helper hook "
1670                     "type=%d, id=%d: error %d returned\n", __func__,
1671                     HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT, error);
1672         }
1673 #endif
1674 }
1675 VNET_SYSUNINIT(tcp, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH, tcp_destroy, NULL);
1676 #endif
1677
1678 void
1679 tcp_fini(void *xtp)
1680 {
1681
1682 }
1683
1684 /*
1685  * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
1686  * tcp_template used to store this data in mbufs, but we now recopy it out
1687  * of the tcpcb each time to conserve mbufs.
1688  */
1689 void
1690 tcpip_fillheaders(struct inpcb *inp, uint16_t port, void *ip_ptr, void *tcp_ptr)
1691 {
1692         struct tcphdr *th = (struct tcphdr *)tcp_ptr;
1693
1694         INP_WLOCK_ASSERT(inp);
1695
1696 #ifdef INET6
1697         if ((inp->inp_vflag & INP_IPV6) != 0) {
1698                 struct ip6_hdr *ip6;
1699
1700                 ip6 = (struct ip6_hdr *)ip_ptr;
1701                 ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
1702                         (inp->inp_flow & IPV6_FLOWINFO_MASK);
1703                 ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
1704                         (IPV6_VERSION & IPV6_VERSION_MASK);
1705                 if (port == 0)
1706                         ip6->ip6_nxt = IPPROTO_TCP;
1707                 else
1708                         ip6->ip6_nxt = IPPROTO_UDP;
1709                 ip6->ip6_plen = htons(sizeof(struct tcphdr));
1710                 ip6->ip6_src = inp->in6p_laddr;
1711                 ip6->ip6_dst = inp->in6p_faddr;
1712         }
1713 #endif /* INET6 */
1714 #if defined(INET6) && defined(INET)
1715         else
1716 #endif
1717 #ifdef INET
1718         {
1719                 struct ip *ip;
1720
1721                 ip = (struct ip *)ip_ptr;
1722                 ip->ip_v = IPVERSION;
1723                 ip->ip_hl = 5;
1724                 ip->ip_tos = inp->inp_ip_tos;
1725                 ip->ip_len = 0;
1726                 ip->ip_id = 0;
1727                 ip->ip_off = 0;
1728                 ip->ip_ttl = inp->inp_ip_ttl;
1729                 ip->ip_sum = 0;
1730                 if (port == 0)
1731                         ip->ip_p = IPPROTO_TCP;
1732                 else
1733                         ip->ip_p = IPPROTO_UDP;
1734                 ip->ip_src = inp->inp_laddr;
1735                 ip->ip_dst = inp->inp_faddr;
1736         }
1737 #endif /* INET */
1738         th->th_sport = inp->inp_lport;
1739         th->th_dport = inp->inp_fport;
1740         th->th_seq = 0;
1741         th->th_ack = 0;
1742         th->th_off = 5;
1743         tcp_set_flags(th, 0);
1744         th->th_win = 0;
1745         th->th_urp = 0;
1746         th->th_sum = 0;         /* in_pseudo() is called later for ipv4 */
1747 }
1748
1749 /*
1750  * Create template to be used to send tcp packets on a connection.
1751  * Allocates an mbuf and fills in a skeletal tcp/ip header.  The only
1752  * use for this function is in keepalives, which use tcp_respond.
1753  */
1754 struct tcptemp *
1755 tcpip_maketemplate(struct inpcb *inp)
1756 {
1757         struct tcptemp *t;
1758
1759         t = malloc(sizeof(*t), M_TEMP, M_NOWAIT);
1760         if (t == NULL)
1761                 return (NULL);
1762         tcpip_fillheaders(inp, 0, (void *)&t->tt_ipgen, (void *)&t->tt_t);
1763         return (t);
1764 }
1765
1766 /*
1767  * Send a single message to the TCP at address specified by
1768  * the given TCP/IP header.  If m == NULL, then we make a copy
1769  * of the tcpiphdr at th and send directly to the addressed host.
1770  * This is used to force keep alive messages out using the TCP
1771  * template for a connection.  If flags are given then we send
1772  * a message back to the TCP which originated the segment th,
1773  * and discard the mbuf containing it and any other attached mbufs.
1774  *
1775  * In any case the ack and sequence number of the transmitted
1776  * segment are as specified by the parameters.
1777  *
1778  * NOTE: If m != NULL, then th must point to *inside* the mbuf.
1779  */
1780 void
1781 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
1782     tcp_seq ack, tcp_seq seq, int flags)
1783 {
1784         struct tcpopt to;
1785         struct inpcb *inp;
1786         struct ip *ip;
1787         struct mbuf *optm;
1788         struct udphdr *uh = NULL;
1789         struct tcphdr *nth;
1790         struct tcp_log_buffer *lgb;
1791         u_char *optp;
1792 #ifdef INET6
1793         struct ip6_hdr *ip6;
1794         int isipv6;
1795 #endif /* INET6 */
1796         int optlen, tlen, win, ulen;
1797         bool incl_opts;
1798         uint16_t port;
1799         int output_ret;
1800 #ifdef INVARIANTS
1801         int thflags = tcp_get_flags(th);
1802 #endif
1803
1804         KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
1805         NET_EPOCH_ASSERT();
1806
1807 #ifdef INET6
1808         isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4);
1809         ip6 = ipgen;
1810 #endif /* INET6 */
1811         ip = ipgen;
1812
1813         if (tp != NULL) {
1814                 inp = tp->t_inpcb;
1815                 KASSERT(inp != NULL, ("tcp control block w/o inpcb"));
1816                 INP_LOCK_ASSERT(inp);
1817         } else
1818                 inp = NULL;
1819
1820         if (m != NULL) {
1821 #ifdef INET6
1822                 if (isipv6 && ip6 && (ip6->ip6_nxt == IPPROTO_UDP))
1823                         port = m->m_pkthdr.tcp_tun_port;
1824                 else
1825 #endif
1826                 if (ip && (ip->ip_p == IPPROTO_UDP))
1827                         port = m->m_pkthdr.tcp_tun_port;
1828                 else
1829                         port = 0;
1830         } else
1831                 port = tp->t_port;
1832
1833         incl_opts = false;
1834         win = 0;
1835         if (tp != NULL) {
1836                 if (!(flags & TH_RST)) {
1837                         win = sbspace(&inp->inp_socket->so_rcv);
1838                         if (win > TCP_MAXWIN << tp->rcv_scale)
1839                                 win = TCP_MAXWIN << tp->rcv_scale;
1840                 }
1841                 if ((tp->t_flags & TF_NOOPT) == 0)
1842                         incl_opts = true;
1843         }
1844         if (m == NULL) {
1845                 m = m_gethdr(M_NOWAIT, MT_DATA);
1846                 if (m == NULL)
1847                         return;
1848                 m->m_data += max_linkhdr;
1849 #ifdef INET6
1850                 if (isipv6) {
1851                         bcopy((caddr_t)ip6, mtod(m, caddr_t),
1852                               sizeof(struct ip6_hdr));
1853                         ip6 = mtod(m, struct ip6_hdr *);
1854                         nth = (struct tcphdr *)(ip6 + 1);
1855                         if (port) {
1856                                 /* Insert a UDP header */
1857                                 uh = (struct udphdr *)nth;
1858                                 uh->uh_sport = htons(V_tcp_udp_tunneling_port);
1859                                 uh->uh_dport = port;
1860                                 nth = (struct tcphdr *)(uh + 1);
1861                         }
1862                 } else
1863 #endif /* INET6 */
1864                 {
1865                         bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
1866                         ip = mtod(m, struct ip *);
1867                         nth = (struct tcphdr *)(ip + 1);
1868                         if (port) {
1869                                 /* Insert a UDP header */
1870                                 uh = (struct udphdr *)nth;
1871                                 uh->uh_sport = htons(V_tcp_udp_tunneling_port);
1872                                 uh->uh_dport = port;
1873                                 nth = (struct tcphdr *)(uh + 1);
1874                         }
1875                 }
1876                 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
1877                 flags = TH_ACK;
1878         } else if ((!M_WRITABLE(m)) || (port != 0)) {
1879                 struct mbuf *n;
1880
1881                 /* Can't reuse 'm', allocate a new mbuf. */
1882                 n = m_gethdr(M_NOWAIT, MT_DATA);
1883                 if (n == NULL) {
1884                         m_freem(m);
1885                         return;
1886                 }
1887
1888                 if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
1889                         m_freem(m);
1890                         m_freem(n);
1891                         return;
1892                 }
1893
1894                 n->m_data += max_linkhdr;
1895                 /* m_len is set later */
1896 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
1897 #ifdef INET6
1898                 if (isipv6) {
1899                         bcopy((caddr_t)ip6, mtod(n, caddr_t),
1900                               sizeof(struct ip6_hdr));
1901                         ip6 = mtod(n, struct ip6_hdr *);
1902                         xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
1903                         nth = (struct tcphdr *)(ip6 + 1);
1904                         if (port) {
1905                                 /* Insert a UDP header */
1906                                 uh = (struct udphdr *)nth;
1907                                 uh->uh_sport = htons(V_tcp_udp_tunneling_port);
1908                                 uh->uh_dport = port;
1909                                 nth = (struct tcphdr *)(uh + 1);
1910                         }
1911                 } else
1912 #endif /* INET6 */
1913                 {
1914                         bcopy((caddr_t)ip, mtod(n, caddr_t), sizeof(struct ip));
1915                         ip = mtod(n, struct ip *);
1916                         xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
1917                         nth = (struct tcphdr *)(ip + 1);
1918                         if (port) {
1919                                 /* Insert a UDP header */
1920                                 uh = (struct udphdr *)nth;
1921                                 uh->uh_sport = htons(V_tcp_udp_tunneling_port);
1922                                 uh->uh_dport = port;
1923                                 nth = (struct tcphdr *)(uh + 1);
1924                         }
1925                 }
1926                 bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
1927                 xchg(nth->th_dport, nth->th_sport, uint16_t);
1928                 th = nth;
1929                 m_freem(m);
1930                 m = n;
1931         } else {
1932                 /*
1933                  *  reuse the mbuf.
1934                  * XXX MRT We inherit the FIB, which is lucky.
1935                  */
1936                 m_freem(m->m_next);
1937                 m->m_next = NULL;
1938                 m->m_data = (caddr_t)ipgen;
1939                 /* m_len is set later */
1940 #ifdef INET6
1941                 if (isipv6) {
1942                         xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
1943                         nth = (struct tcphdr *)(ip6 + 1);
1944                 } else
1945 #endif /* INET6 */
1946                 {
1947                         xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
1948                         nth = (struct tcphdr *)(ip + 1);
1949                 }
1950                 if (th != nth) {
1951                         /*
1952                          * this is usually a case when an extension header
1953                          * exists between the IPv6 header and the
1954                          * TCP header.
1955                          */
1956                         nth->th_sport = th->th_sport;
1957                         nth->th_dport = th->th_dport;
1958                 }
1959                 xchg(nth->th_dport, nth->th_sport, uint16_t);
1960 #undef xchg
1961         }
1962         tlen = 0;
1963 #ifdef INET6
1964         if (isipv6)
1965                 tlen = sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
1966 #endif
1967 #if defined(INET) && defined(INET6)
1968         else
1969 #endif
1970 #ifdef INET
1971                 tlen = sizeof (struct tcpiphdr);
1972 #endif
1973         if (port)
1974                 tlen += sizeof (struct udphdr);
1975 #ifdef INVARIANTS
1976         m->m_len = 0;
1977         KASSERT(M_TRAILINGSPACE(m) >= tlen,
1978             ("Not enough trailing space for message (m=%p, need=%d, have=%ld)",
1979             m, tlen, (long)M_TRAILINGSPACE(m)));
1980 #endif
1981         m->m_len = tlen;
1982         to.to_flags = 0;
1983         if (incl_opts) {
1984                 /* Make sure we have room. */
1985                 if (M_TRAILINGSPACE(m) < TCP_MAXOLEN) {
1986                         m->m_next = m_get(M_NOWAIT, MT_DATA);
1987                         if (m->m_next) {
1988                                 optp = mtod(m->m_next, u_char *);
1989                                 optm = m->m_next;
1990                         } else
1991                                 incl_opts = false;
1992                 } else {
1993                         optp = (u_char *) (nth + 1);
1994                         optm = m;
1995                 }
1996         }
1997         if (incl_opts) {
1998                 /* Timestamps. */
1999                 if (tp->t_flags & TF_RCVD_TSTMP) {
2000                         to.to_tsval = tcp_ts_getticks() + tp->ts_offset;
2001                         to.to_tsecr = tp->ts_recent;
2002                         to.to_flags |= TOF_TS;
2003                 }
2004 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
2005                 /* TCP-MD5 (RFC2385). */
2006                 if (tp->t_flags & TF_SIGNATURE)
2007                         to.to_flags |= TOF_SIGNATURE;
2008 #endif
2009                 /* Add the options. */
2010                 tlen += optlen = tcp_addoptions(&to, optp);
2011
2012                 /* Update m_len in the correct mbuf. */
2013                 optm->m_len += optlen;
2014         } else
2015                 optlen = 0;
2016 #ifdef INET6
2017         if (isipv6) {
2018                 if (uh) {
2019                         ulen = tlen - sizeof(struct ip6_hdr);
2020                         uh->uh_ulen = htons(ulen);
2021                 }
2022                 ip6->ip6_flow = 0;
2023                 ip6->ip6_vfc = IPV6_VERSION;
2024                 if (port)
2025                         ip6->ip6_nxt = IPPROTO_UDP;
2026                 else
2027                         ip6->ip6_nxt = IPPROTO_TCP;
2028                 ip6->ip6_plen = htons(tlen - sizeof(*ip6));
2029         }
2030 #endif
2031 #if defined(INET) && defined(INET6)
2032         else
2033 #endif
2034 #ifdef INET
2035         {
2036                 if (uh) {
2037                         ulen = tlen - sizeof(struct ip);
2038                         uh->uh_ulen = htons(ulen);
2039                 }
2040                 ip->ip_len = htons(tlen);
2041                 ip->ip_ttl = V_ip_defttl;
2042                 if (port) {
2043                         ip->ip_p = IPPROTO_UDP;
2044                 } else {
2045                         ip->ip_p = IPPROTO_TCP;
2046                 }
2047                 if (V_path_mtu_discovery)
2048                         ip->ip_off |= htons(IP_DF);
2049         }
2050 #endif
2051         m->m_pkthdr.len = tlen;
2052         m->m_pkthdr.rcvif = NULL;
2053 #ifdef MAC
2054         if (inp != NULL) {
2055                 /*
2056                  * Packet is associated with a socket, so allow the
2057                  * label of the response to reflect the socket label.
2058                  */
2059                 INP_LOCK_ASSERT(inp);
2060                 mac_inpcb_create_mbuf(inp, m);
2061         } else {
2062                 /*
2063                  * Packet is not associated with a socket, so possibly
2064                  * update the label in place.
2065                  */
2066                 mac_netinet_tcp_reply(m);
2067         }
2068 #endif
2069         nth->th_seq = htonl(seq);
2070         nth->th_ack = htonl(ack);
2071         nth->th_off = (sizeof (struct tcphdr) + optlen) >> 2;
2072         tcp_set_flags(nth, flags);
2073         if (tp != NULL)
2074                 nth->th_win = htons((u_short) (win >> tp->rcv_scale));
2075         else
2076                 nth->th_win = htons((u_short)win);
2077         nth->th_urp = 0;
2078
2079 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
2080         if (to.to_flags & TOF_SIGNATURE) {
2081                 if (!TCPMD5_ENABLED() ||
2082                     TCPMD5_OUTPUT(m, nth, to.to_signature) != 0) {
2083                         m_freem(m);
2084                         return;
2085                 }
2086         }
2087 #endif
2088
2089 #ifdef INET6
2090         if (isipv6) {
2091                 if (port) {
2092                         m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
2093                         m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
2094                         uh->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
2095                         nth->th_sum = 0;
2096                 } else {
2097                         m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
2098                         m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
2099                         nth->th_sum = in6_cksum_pseudo(ip6,
2100                             tlen - sizeof(struct ip6_hdr), IPPROTO_TCP, 0);
2101                 }
2102                 ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb :
2103                     NULL, NULL);
2104         }
2105 #endif /* INET6 */
2106 #if defined(INET6) && defined(INET)
2107         else
2108 #endif
2109 #ifdef INET
2110         {
2111                 if (port) {
2112                         uh->uh_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
2113                             htons(ulen + IPPROTO_UDP));
2114                         m->m_pkthdr.csum_flags = CSUM_UDP;
2115                         m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
2116                         nth->th_sum = 0;
2117                 } else {
2118                         m->m_pkthdr.csum_flags = CSUM_TCP;
2119                         m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
2120                         nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
2121                             htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
2122                 }
2123         }
2124 #endif /* INET */
2125 #ifdef TCPDEBUG
2126         if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
2127                 tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
2128 #endif
2129         TCP_PROBE3(debug__output, tp, th, m);
2130         if (flags & TH_RST)
2131                 TCP_PROBE5(accept__refused, NULL, NULL, m, tp, nth);
2132         lgb = NULL;
2133         if ((tp != NULL) && (tp->t_logstate != TCP_LOG_STATE_OFF)) {
2134                 if (INP_WLOCKED(inp)) {
2135                         union tcp_log_stackspecific log;
2136                         struct timeval tv;
2137
2138                         memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2139                         log.u_bbr.inhpts = tp->t_inpcb->inp_in_hpts;
2140                         log.u_bbr.flex8 = 4;
2141                         log.u_bbr.pkts_out = tp->t_maxseg;
2142                         log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2143                         log.u_bbr.delivered = 0;
2144                         lgb = tcp_log_event_(tp, nth, NULL, NULL, TCP_LOG_OUT,
2145                             ERRNO_UNK, 0, &log, false, NULL, NULL, 0, &tv);
2146                 } else {
2147                         /*
2148                          * We can not log the packet, since we only own the
2149                          * read lock, but a write lock is needed. The read lock
2150                          * is not upgraded to a write lock, since only getting
2151                          * the read lock was done intentionally to improve the
2152                          * handling of SYN flooding attacks.
2153                          * This happens only for pure SYN segments received in
2154                          * the initial CLOSED state, or received in a more
2155                          * advanced state than listen and the UDP encapsulation
2156                          * port is unexpected.
2157                          * The incoming SYN segments do not really belong to
2158                          * the TCP connection and the handling does not change
2159                          * the state of the TCP connection. Therefore, the
2160                          * sending of the RST segments is not logged. Please
2161                          * note that also the incoming SYN segments are not
2162                          * logged.
2163                          *
2164                          * The following code ensures that the above description
2165                          * is and stays correct.
2166                          */
2167                         KASSERT((thflags & (TH_ACK|TH_SYN)) == TH_SYN &&
2168                             (tp->t_state == TCPS_CLOSED ||
2169                             (tp->t_state > TCPS_LISTEN && tp->t_port != port)),
2170                             ("%s: Logging of TCP segment with flags 0x%b and "
2171                             "UDP encapsulation port %u skipped in state %s",
2172                             __func__, thflags, PRINT_TH_FLAGS,
2173                             ntohs(port), tcpstates[tp->t_state]));
2174                 }
2175         }
2176
2177 #ifdef INET6
2178         if (isipv6) {
2179                 TCP_PROBE5(send, NULL, tp, ip6, tp, nth);
2180                 output_ret = ip6_output(m, NULL, NULL, 0, NULL, NULL, inp);
2181         }
2182 #endif /* INET6 */
2183 #if defined(INET) && defined(INET6)
2184         else
2185 #endif
2186 #ifdef INET
2187         {
2188                 TCP_PROBE5(send, NULL, tp, ip, tp, nth);
2189                 output_ret = ip_output(m, NULL, NULL, 0, NULL, inp);
2190         }
2191 #endif
2192         if (lgb != NULL)
2193                 lgb->tlb_errno = output_ret;
2194 }
2195
2196 /*
2197  * Create a new TCP control block, making an
2198  * empty reassembly queue and hooking it to the argument
2199  * protocol control block.  The `inp' parameter must have
2200  * come from the zone allocator set up in tcp_init().
2201  */
2202 struct tcpcb *
2203 tcp_newtcpcb(struct inpcb *inp)
2204 {
2205         struct tcpcb_mem *tm;
2206         struct tcpcb *tp;
2207 #ifdef INET6
2208         int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
2209 #endif /* INET6 */
2210
2211         tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO);
2212         if (tm == NULL)
2213                 return (NULL);
2214         tp = &tm->tcb;
2215
2216         /* Initialise cc_var struct for this tcpcb. */
2217         tp->ccv = &tm->ccv;
2218         tp->ccv->type = IPPROTO_TCP;
2219         tp->ccv->ccvc.tcp = tp;
2220         rw_rlock(&tcp_function_lock);
2221         tp->t_fb = tcp_func_set_ptr;
2222         refcount_acquire(&tp->t_fb->tfb_refcnt);
2223         rw_runlock(&tcp_function_lock);
2224         /*
2225          * Use the current system default CC algorithm.
2226          */
2227         cc_attach(tp, CC_DEFAULT_ALGO());
2228
2229         /*
2230          * The tcpcb will hold a reference on its inpcb until tcp_discardcb()
2231          * is called.
2232          */
2233         in_pcbref(inp); /* Reference for tcpcb */
2234         tp->t_inpcb = inp;
2235
2236         if (CC_ALGO(tp)->cb_init != NULL)
2237                 if (CC_ALGO(tp)->cb_init(tp->ccv, NULL) > 0) {
2238                         cc_detach(tp);
2239                         if (tp->t_fb->tfb_tcp_fb_fini)
2240                                 (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
2241                         in_pcbrele_wlocked(inp);
2242                         refcount_release(&tp->t_fb->tfb_refcnt);
2243                         uma_zfree(V_tcpcb_zone, tm);
2244                         return (NULL);
2245                 }
2246
2247 #ifdef TCP_HHOOK
2248         tp->osd = &tm->osd;
2249         if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) {
2250                 if (tp->t_fb->tfb_tcp_fb_fini)
2251                         (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
2252                 in_pcbrele_wlocked(inp);
2253                 refcount_release(&tp->t_fb->tfb_refcnt);
2254                 uma_zfree(V_tcpcb_zone, tm);
2255                 return (NULL);
2256         }
2257 #endif
2258
2259 #ifdef VIMAGE
2260         tp->t_vnet = inp->inp_vnet;
2261 #endif
2262         tp->t_timers = &tm->tt;
2263         TAILQ_INIT(&tp->t_segq);
2264         tp->t_maxseg =
2265 #ifdef INET6
2266                 isipv6 ? V_tcp_v6mssdflt :
2267 #endif /* INET6 */
2268                 V_tcp_mssdflt;
2269
2270         /* Set up our timeouts. */
2271         callout_init(&tp->t_timers->tt_rexmt, 1);
2272         callout_init(&tp->t_timers->tt_persist, 1);
2273         callout_init(&tp->t_timers->tt_keep, 1);
2274         callout_init(&tp->t_timers->tt_2msl, 1);
2275         callout_init(&tp->t_timers->tt_delack, 1);
2276
2277         if (V_tcp_do_rfc1323)
2278                 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
2279         if (V_tcp_do_sack)
2280                 tp->t_flags |= TF_SACK_PERMIT;
2281         TAILQ_INIT(&tp->snd_holes);
2282
2283         /*
2284          * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
2285          * rtt estimate.  Set rttvar so that srtt + 4 * rttvar gives
2286          * reasonable initial retransmit time.
2287          */
2288         tp->t_srtt = TCPTV_SRTTBASE;
2289         tp->t_rttvar = ((tcp_rexmit_initial - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
2290         tp->t_rttmin = tcp_rexmit_min;
2291         tp->t_rxtcur = tcp_rexmit_initial;
2292         tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
2293         tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
2294         tp->t_rcvtime = ticks;
2295         /*
2296          * IPv4 TTL initialization is necessary for an IPv6 socket as well,
2297          * because the socket may be bound to an IPv6 wildcard address,
2298          * which may match an IPv4-mapped IPv6 address.
2299          */
2300         inp->inp_ip_ttl = V_ip_defttl;
2301         inp->inp_ppcb = tp;
2302 #ifdef TCPPCAP
2303         /*
2304          * Init the TCP PCAP queues.
2305          */
2306         tcp_pcap_tcpcb_init(tp);
2307 #endif
2308 #ifdef TCP_BLACKBOX
2309         /* Initialize the per-TCPCB log data. */
2310         tcp_log_tcpcbinit(tp);
2311 #endif
2312         tp->t_pacing_rate = -1;
2313         if (tp->t_fb->tfb_tcp_fb_init) {
2314                 if ((*tp->t_fb->tfb_tcp_fb_init)(tp)) {
2315                         refcount_release(&tp->t_fb->tfb_refcnt);
2316                         in_pcbrele_wlocked(inp);
2317                         uma_zfree(V_tcpcb_zone, tm);
2318                         return (NULL);
2319                 }
2320         }
2321 #ifdef STATS
2322         if (V_tcp_perconn_stats_enable == 1)
2323                 tp->t_stats = stats_blob_alloc(V_tcp_perconn_stats_dflt_tpl, 0);
2324 #endif
2325         if (V_tcp_do_lrd)
2326                 tp->t_flags |= TF_LRD;
2327         return (tp);            /* XXX */
2328 }
2329
2330 /*
2331  * Drop a TCP connection, reporting
2332  * the specified error.  If connection is synchronized,
2333  * then send a RST to peer.
2334  */
2335 struct tcpcb *
2336 tcp_drop(struct tcpcb *tp, int errno)
2337 {
2338         struct socket *so = tp->t_inpcb->inp_socket;
2339
2340         NET_EPOCH_ASSERT();
2341         INP_WLOCK_ASSERT(tp->t_inpcb);
2342
2343         if (TCPS_HAVERCVDSYN(tp->t_state)) {
2344                 tcp_state_change(tp, TCPS_CLOSED);
2345                 /* Don't use tcp_output() here due to possible recursion. */
2346                 (void)tcp_output_nodrop(tp);
2347                 TCPSTAT_INC(tcps_drops);
2348         } else
2349                 TCPSTAT_INC(tcps_conndrops);
2350         if (errno == ETIMEDOUT && tp->t_softerror)
2351                 errno = tp->t_softerror;
2352         so->so_error = errno;
2353         return (tcp_close(tp));
2354 }
2355
2356 void
2357 tcp_discardcb(struct tcpcb *tp)
2358 {
2359         struct inpcb *inp = tp->t_inpcb;
2360
2361         INP_WLOCK_ASSERT(inp);
2362
2363         /*
2364          * Make sure that all of our timers are stopped before we delete the
2365          * PCB.
2366          *
2367          * If stopping a timer fails, we schedule a discard function in same
2368          * callout, and the last discard function called will take care of
2369          * deleting the tcpcb.
2370          */
2371         tp->t_timers->tt_draincnt = 0;
2372         tcp_timer_stop(tp, TT_REXMT);
2373         tcp_timer_stop(tp, TT_PERSIST);
2374         tcp_timer_stop(tp, TT_KEEP);
2375         tcp_timer_stop(tp, TT_2MSL);
2376         tcp_timer_stop(tp, TT_DELACK);
2377         if (tp->t_fb->tfb_tcp_timer_stop_all) {
2378                 /*
2379                  * Call the stop-all function of the methods,
2380                  * this function should call the tcp_timer_stop()
2381                  * method with each of the function specific timeouts.
2382                  * That stop will be called via the tfb_tcp_timer_stop()
2383                  * which should use the async drain function of the
2384                  * callout system (see tcp_var.h).
2385                  */
2386                 tp->t_fb->tfb_tcp_timer_stop_all(tp);
2387         }
2388
2389         /* free the reassembly queue, if any */
2390         tcp_reass_flush(tp);
2391
2392 #ifdef TCP_OFFLOAD
2393         /* Disconnect offload device, if any. */
2394         if (tp->t_flags & TF_TOE)
2395                 tcp_offload_detach(tp);
2396 #endif
2397
2398         tcp_free_sackholes(tp);
2399
2400 #ifdef TCPPCAP
2401         /* Free the TCP PCAP queues. */
2402         tcp_pcap_drain(&(tp->t_inpkts));
2403         tcp_pcap_drain(&(tp->t_outpkts));
2404 #endif
2405
2406         /* Allow the CC algorithm to clean up after itself. */
2407         if (CC_ALGO(tp)->cb_destroy != NULL)
2408                 CC_ALGO(tp)->cb_destroy(tp->ccv);
2409         CC_DATA(tp) = NULL;
2410         /* Detach from the CC algorithm */
2411         cc_detach(tp);
2412
2413 #ifdef TCP_HHOOK
2414         khelp_destroy_osd(tp->osd);
2415 #endif
2416 #ifdef STATS
2417         stats_blob_destroy(tp->t_stats);
2418 #endif
2419
2420         CC_ALGO(tp) = NULL;
2421         inp->inp_ppcb = NULL;
2422         if (tp->t_timers->tt_draincnt == 0) {
2423                 bool released __diagused;
2424
2425                 released = tcp_freecb(tp);
2426                 KASSERT(!released, ("%s: inp %p should not have been released "
2427                     "here", __func__, inp));
2428         }
2429 }
2430
2431 bool
2432 tcp_freecb(struct tcpcb *tp)
2433 {
2434         struct inpcb *inp = tp->t_inpcb;
2435         struct socket *so = inp->inp_socket;
2436 #ifdef INET6
2437         bool isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
2438 #endif
2439
2440         INP_WLOCK_ASSERT(inp);
2441         MPASS(tp->t_timers->tt_draincnt == 0);
2442
2443         /* We own the last reference on tcpcb, let's free it. */
2444 #ifdef TCP_BLACKBOX
2445         tcp_log_tcpcbfini(tp);
2446 #endif
2447         TCPSTATES_DEC(tp->t_state);
2448         if (tp->t_fb->tfb_tcp_fb_fini)
2449                 (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
2450
2451         /*
2452          * If we got enough samples through the srtt filter,
2453          * save the rtt and rttvar in the routing entry.
2454          * 'Enough' is arbitrarily defined as 4 rtt samples.
2455          * 4 samples is enough for the srtt filter to converge
2456          * to within enough % of the correct value; fewer samples
2457          * and we could save a bogus rtt. The danger is not high
2458          * as tcp quickly recovers from everything.
2459          * XXX: Works very well but needs some more statistics!
2460          *
2461          * XXXRRS: Updating must be after the stack fini() since
2462          * that may be converting some internal representation of
2463          * say srtt etc into the general one used by other stacks.
2464          * Lets also at least protect against the so being NULL
2465          * as RW stated below.
2466          */
2467         if ((tp->t_rttupdated >= 4) && (so != NULL)) {
2468                 struct hc_metrics_lite metrics;
2469                 uint32_t ssthresh;
2470
2471                 bzero(&metrics, sizeof(metrics));
2472                 /*
2473                  * Update the ssthresh always when the conditions below
2474                  * are satisfied. This gives us better new start value
2475                  * for the congestion avoidance for new connections.
2476                  * ssthresh is only set if packet loss occurred on a session.
2477                  *
2478                  * XXXRW: 'so' may be NULL here, and/or socket buffer may be
2479                  * being torn down.  Ideally this code would not use 'so'.
2480                  */
2481                 ssthresh = tp->snd_ssthresh;
2482                 if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) {
2483                         /*
2484                          * convert the limit from user data bytes to
2485                          * packets then to packet data bytes.
2486                          */
2487                         ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg;
2488                         if (ssthresh < 2)
2489                                 ssthresh = 2;
2490                         ssthresh *= (tp->t_maxseg +
2491 #ifdef INET6
2492                             (isipv6 ? sizeof (struct ip6_hdr) +
2493                             sizeof (struct tcphdr) :
2494 #endif
2495                             sizeof (struct tcpiphdr)
2496 #ifdef INET6
2497                             )
2498 #endif
2499                             );
2500                 } else
2501                         ssthresh = 0;
2502                 metrics.rmx_ssthresh = ssthresh;
2503
2504                 metrics.rmx_rtt = tp->t_srtt;
2505                 metrics.rmx_rttvar = tp->t_rttvar;
2506                 metrics.rmx_cwnd = tp->snd_cwnd;
2507                 metrics.rmx_sendpipe = 0;
2508                 metrics.rmx_recvpipe = 0;
2509
2510                 tcp_hc_update(&inp->inp_inc, &metrics);
2511         }
2512
2513         refcount_release(&tp->t_fb->tfb_refcnt);
2514         uma_zfree(V_tcpcb_zone, tp);
2515
2516         return (in_pcbrele_wlocked(inp));
2517 }
2518
2519 /*
2520  * Attempt to close a TCP control block, marking it as dropped, and freeing
2521  * the socket if we hold the only reference.
2522  */
2523 struct tcpcb *
2524 tcp_close(struct tcpcb *tp)
2525 {
2526         struct inpcb *inp = tp->t_inpcb;
2527         struct socket *so;
2528
2529         INP_WLOCK_ASSERT(inp);
2530
2531 #ifdef TCP_OFFLOAD
2532         if (tp->t_state == TCPS_LISTEN)
2533                 tcp_offload_listen_stop(tp);
2534 #endif
2535         /*
2536          * This releases the TFO pending counter resource for TFO listen
2537          * sockets as well as passively-created TFO sockets that transition
2538          * from SYN_RECEIVED to CLOSED.
2539          */
2540         if (tp->t_tfo_pending) {
2541                 tcp_fastopen_decrement_counter(tp->t_tfo_pending);
2542                 tp->t_tfo_pending = NULL;
2543         }
2544 #ifdef TCPHPTS
2545         tcp_hpts_remove(inp);
2546 #endif
2547         in_pcbdrop(inp);
2548         TCPSTAT_INC(tcps_closed);
2549         if (tp->t_state != TCPS_CLOSED)
2550                 tcp_state_change(tp, TCPS_CLOSED);
2551         KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
2552         so = inp->inp_socket;
2553         soisdisconnected(so);
2554         if (inp->inp_flags & INP_SOCKREF) {
2555                 inp->inp_flags &= ~INP_SOCKREF;
2556                 INP_WUNLOCK(inp);
2557                 sorele(so);
2558                 return (NULL);
2559         }
2560         return (tp);
2561 }
2562
2563 /*
2564  * Notify a tcp user of an asynchronous error;
2565  * store error as soft error, but wake up user
2566  * (for now, won't do anything until can select for soft error).
2567  *
2568  * Do not wake up user since there currently is no mechanism for
2569  * reporting soft errors (yet - a kqueue filter may be added).
2570  */
2571 static struct inpcb *
2572 tcp_notify(struct inpcb *inp, int error)
2573 {
2574         struct tcpcb *tp;
2575
2576         INP_WLOCK_ASSERT(inp);
2577
2578         if ((inp->inp_flags & INP_TIMEWAIT) ||
2579             (inp->inp_flags & INP_DROPPED))
2580                 return (inp);
2581
2582         tp = intotcpcb(inp);
2583         KASSERT(tp != NULL, ("tcp_notify: tp == NULL"));
2584
2585         /*
2586          * Ignore some errors if we are hooked up.
2587          * If connection hasn't completed, has retransmitted several times,
2588          * and receives a second error, give up now.  This is better
2589          * than waiting a long time to establish a connection that
2590          * can never complete.
2591          */
2592         if (tp->t_state == TCPS_ESTABLISHED &&
2593             (error == EHOSTUNREACH || error == ENETUNREACH ||
2594              error == EHOSTDOWN)) {
2595                 if (inp->inp_route.ro_nh) {
2596                         NH_FREE(inp->inp_route.ro_nh);
2597                         inp->inp_route.ro_nh = (struct nhop_object *)NULL;
2598                 }
2599                 return (inp);
2600         } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
2601             tp->t_softerror) {
2602                 tp = tcp_drop(tp, error);
2603                 if (tp != NULL)
2604                         return (inp);
2605                 else
2606                         return (NULL);
2607         } else {
2608                 tp->t_softerror = error;
2609                 return (inp);
2610         }
2611 #if 0
2612         wakeup( &so->so_timeo);
2613         sorwakeup(so);
2614         sowwakeup(so);
2615 #endif
2616 }
2617
2618 static int
2619 tcp_pcblist(SYSCTL_HANDLER_ARGS)
2620 {
2621         struct inpcb_iterator inpi = INP_ALL_ITERATOR(&V_tcbinfo,
2622             INPLOOKUP_RLOCKPCB);
2623         struct xinpgen xig;
2624         struct inpcb *inp;
2625         int error;
2626
2627         if (req->newptr != NULL)
2628                 return (EPERM);
2629
2630         if (req->oldptr == NULL) {
2631                 int n;
2632
2633                 n = V_tcbinfo.ipi_count +
2634                     counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
2635                 n += imax(n / 8, 10);
2636                 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
2637                 return (0);
2638         }
2639
2640         if ((error = sysctl_wire_old_buffer(req, 0)) != 0)
2641                 return (error);
2642
2643         bzero(&xig, sizeof(xig));
2644         xig.xig_len = sizeof xig;
2645         xig.xig_count = V_tcbinfo.ipi_count +
2646             counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
2647         xig.xig_gen = V_tcbinfo.ipi_gencnt;
2648         xig.xig_sogen = so_gencnt;
2649         error = SYSCTL_OUT(req, &xig, sizeof xig);
2650         if (error)
2651                 return (error);
2652
2653         error = syncache_pcblist(req);
2654         if (error)
2655                 return (error);
2656
2657         while ((inp = inp_next(&inpi)) != NULL) {
2658                 if (inp->inp_gencnt <= xig.xig_gen) {
2659                         int crerr;
2660
2661                         /*
2662                          * XXX: This use of cr_cansee(), introduced with
2663                          * TCP state changes, is not quite right, but for
2664                          * now, better than nothing.
2665                          */
2666                         if (inp->inp_flags & INP_TIMEWAIT) {
2667                                 if (intotw(inp) != NULL)
2668                                         crerr = cr_cansee(req->td->td_ucred,
2669                                             intotw(inp)->tw_cred);
2670                                 else
2671                                         crerr = EINVAL; /* Skip this inp. */
2672                         } else
2673                                 crerr = cr_canseeinpcb(req->td->td_ucred, inp);
2674                         if (crerr == 0) {
2675                                 struct xtcpcb xt;
2676
2677                                 tcp_inptoxtp(inp, &xt);
2678                                 error = SYSCTL_OUT(req, &xt, sizeof xt);
2679                                 if (error) {
2680                                         INP_RUNLOCK(inp);
2681                                         break;
2682                                 } else
2683                                         continue;
2684                         }
2685                 }
2686         }
2687
2688         if (!error) {
2689                 /*
2690                  * Give the user an updated idea of our state.
2691                  * If the generation differs from what we told
2692                  * her before, she knows that something happened
2693                  * while we were processing this request, and it
2694                  * might be necessary to retry.
2695                  */
2696                 xig.xig_gen = V_tcbinfo.ipi_gencnt;
2697                 xig.xig_sogen = so_gencnt;
2698                 xig.xig_count = V_tcbinfo.ipi_count +
2699                     counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
2700                 error = SYSCTL_OUT(req, &xig, sizeof xig);
2701         }
2702
2703         return (error);
2704 }
2705
2706 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist,
2707     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_NEEDGIANT,
2708     NULL, 0, tcp_pcblist, "S,xtcpcb",
2709     "List of active TCP connections");
2710
2711 #ifdef INET
2712 static int
2713 tcp_getcred(SYSCTL_HANDLER_ARGS)
2714 {
2715         struct xucred xuc;
2716         struct sockaddr_in addrs[2];
2717         struct epoch_tracker et;
2718         struct inpcb *inp;
2719         int error;
2720
2721         error = priv_check(req->td, PRIV_NETINET_GETCRED);
2722         if (error)
2723                 return (error);
2724         error = SYSCTL_IN(req, addrs, sizeof(addrs));
2725         if (error)
2726                 return (error);
2727         NET_EPOCH_ENTER(et);
2728         inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
2729             addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL);
2730         NET_EPOCH_EXIT(et);
2731         if (inp != NULL) {
2732                 if (inp->inp_socket == NULL)
2733                         error = ENOENT;
2734                 if (error == 0)
2735                         error = cr_canseeinpcb(req->td->td_ucred, inp);
2736                 if (error == 0)
2737                         cru2x(inp->inp_cred, &xuc);
2738                 INP_RUNLOCK(inp);
2739         } else
2740                 error = ENOENT;
2741         if (error == 0)
2742                 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
2743         return (error);
2744 }
2745
2746 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
2747     CTLTYPE_OPAQUE | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_NEEDGIANT,
2748     0, 0, tcp_getcred, "S,xucred",
2749     "Get the xucred of a TCP connection");
2750 #endif /* INET */
2751
2752 #ifdef INET6
2753 static int
2754 tcp6_getcred(SYSCTL_HANDLER_ARGS)
2755 {
2756         struct epoch_tracker et;
2757         struct xucred xuc;
2758         struct sockaddr_in6 addrs[2];
2759         struct inpcb *inp;
2760         int error;
2761 #ifdef INET
2762         int mapped = 0;
2763 #endif
2764
2765         error = priv_check(req->td, PRIV_NETINET_GETCRED);
2766         if (error)
2767                 return (error);
2768         error = SYSCTL_IN(req, addrs, sizeof(addrs));
2769         if (error)
2770                 return (error);
2771         if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
2772             (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
2773                 return (error);
2774         }
2775         if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
2776 #ifdef INET
2777                 if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
2778                         mapped = 1;
2779                 else
2780 #endif
2781                         return (EINVAL);
2782         }
2783
2784         NET_EPOCH_ENTER(et);
2785 #ifdef INET
2786         if (mapped == 1)
2787                 inp = in_pcblookup(&V_tcbinfo,
2788                         *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
2789                         addrs[1].sin6_port,
2790                         *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
2791                         addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL);
2792         else
2793 #endif
2794                 inp = in6_pcblookup(&V_tcbinfo,
2795                         &addrs[1].sin6_addr, addrs[1].sin6_port,
2796                         &addrs[0].sin6_addr, addrs[0].sin6_port,
2797                         INPLOOKUP_RLOCKPCB, NULL);
2798         NET_EPOCH_EXIT(et);
2799         if (inp != NULL) {
2800                 if (inp->inp_socket == NULL)
2801                         error = ENOENT;
2802                 if (error == 0)
2803                         error = cr_canseeinpcb(req->td->td_ucred, inp);
2804                 if (error == 0)
2805                         cru2x(inp->inp_cred, &xuc);
2806                 INP_RUNLOCK(inp);
2807         } else
2808                 error = ENOENT;
2809         if (error == 0)
2810                 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
2811         return (error);
2812 }
2813
2814 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
2815     CTLTYPE_OPAQUE | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_NEEDGIANT,
2816     0, 0, tcp6_getcred, "S,xucred",
2817     "Get the xucred of a TCP6 connection");
2818 #endif /* INET6 */
2819
2820 #ifdef INET
2821 /* Path MTU to try next when a fragmentation-needed message is received. */
2822 static inline int
2823 tcp_next_pmtu(const struct icmp *icp, const struct ip *ip)
2824 {
2825         int mtu = ntohs(icp->icmp_nextmtu);
2826
2827         /* If no alternative MTU was proposed, try the next smaller one. */
2828         if (!mtu)
2829                 mtu = ip_next_mtu(ntohs(ip->ip_len), 1);
2830         if (mtu < V_tcp_minmss + sizeof(struct tcpiphdr))
2831                 mtu = V_tcp_minmss + sizeof(struct tcpiphdr);
2832
2833         return (mtu);
2834 }
2835
2836 static void
2837 tcp_ctlinput_with_port(int cmd, struct sockaddr *sa, void *vip, uint16_t port)
2838 {
2839         struct ip *ip = vip;
2840         struct tcphdr *th;
2841         struct in_addr faddr;
2842         struct inpcb *inp;
2843         struct tcpcb *tp;
2844         struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
2845         struct icmp *icp;
2846         struct in_conninfo inc;
2847         tcp_seq icmp_tcp_seq;
2848         int mtu;
2849
2850         faddr = ((struct sockaddr_in *)sa)->sin_addr;
2851         if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
2852                 return;
2853
2854         if (cmd == PRC_MSGSIZE)
2855                 notify = tcp_mtudisc_notify;
2856         else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
2857                 cmd == PRC_UNREACH_PORT || cmd == PRC_UNREACH_PROTOCOL ||
2858                 cmd == PRC_TIMXCEED_INTRANS) && ip)
2859                 notify = tcp_drop_syn_sent;
2860
2861         /*
2862          * Hostdead is ugly because it goes linearly through all PCBs.
2863          * XXX: We never get this from ICMP, otherwise it makes an
2864          * excellent DoS attack on machines with many connections.
2865          */
2866         else if (cmd == PRC_HOSTDEAD)
2867                 ip = NULL;
2868         else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
2869                 return;
2870
2871         if (ip == NULL) {
2872                 in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify);
2873                 return;
2874         }
2875
2876         icp = (struct icmp *)((caddr_t)ip - offsetof(struct icmp, icmp_ip));
2877         th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
2878         inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport, ip->ip_src,
2879             th->th_sport, INPLOOKUP_WLOCKPCB, NULL);
2880         if (inp != NULL && PRC_IS_REDIRECT(cmd)) {
2881                 /* signal EHOSTDOWN, as it flushes the cached route */
2882                 inp = (*notify)(inp, EHOSTDOWN);
2883                 goto out;
2884         }
2885         icmp_tcp_seq = th->th_seq;
2886         if (inp != NULL)  {
2887                 if (!(inp->inp_flags & INP_TIMEWAIT) &&
2888                     !(inp->inp_flags & INP_DROPPED) &&
2889                     !(inp->inp_socket == NULL)) {
2890                         tp = intotcpcb(inp);
2891 #ifdef TCP_OFFLOAD
2892                         if (tp->t_flags & TF_TOE && cmd == PRC_MSGSIZE) {
2893                                 /*
2894                                  * MTU discovery for offloaded connections.  Let
2895                                  * the TOE driver verify seq# and process it.
2896                                  */
2897                                 mtu = tcp_next_pmtu(icp, ip);
2898                                 tcp_offload_pmtu_update(tp, icmp_tcp_seq, mtu);
2899                                 goto out;
2900                         }
2901 #endif
2902                         if (tp->t_port != port) {
2903                                 goto out;
2904                         }
2905                         if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
2906                             SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
2907                                 if (cmd == PRC_MSGSIZE) {
2908                                         /*
2909                                          * MTU discovery: we got a needfrag and
2910                                          * will potentially try a lower MTU.
2911                                          */
2912                                         mtu = tcp_next_pmtu(icp, ip);
2913
2914                                         /*
2915                                          * Only process the offered MTU if it
2916                                          * is smaller than the current one.
2917                                          */
2918                                         if (mtu < tp->t_maxseg +
2919                                             sizeof(struct tcpiphdr)) {
2920                                                 bzero(&inc, sizeof(inc));
2921                                                 inc.inc_faddr = faddr;
2922                                                 inc.inc_fibnum =
2923                                                     inp->inp_inc.inc_fibnum;
2924                                                 tcp_hc_updatemtu(&inc, mtu);
2925                                                 inp = tcp_mtudisc(inp, mtu);
2926                                         }
2927                                 } else
2928                                         inp = (*notify)(inp,
2929                                             inetctlerrmap[cmd]);
2930                         }
2931                 }
2932         } else {
2933                 bzero(&inc, sizeof(inc));
2934                 inc.inc_fport = th->th_dport;
2935                 inc.inc_lport = th->th_sport;
2936                 inc.inc_faddr = faddr;
2937                 inc.inc_laddr = ip->ip_src;
2938                 syncache_unreach(&inc, icmp_tcp_seq, port);
2939         }
2940 out:
2941         if (inp != NULL)
2942                 INP_WUNLOCK(inp);
2943 }
2944
2945 void
2946 tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
2947 {
2948         tcp_ctlinput_with_port(cmd, sa, vip, htons(0));
2949 }
2950
2951 void
2952 tcp_ctlinput_viaudp(int cmd, struct sockaddr *sa, void *vip, void *unused)
2953 {
2954         /* Its a tunneled TCP over UDP icmp */
2955         struct ip *outer_ip, *inner_ip;
2956         struct icmp *icmp;
2957         struct udphdr *udp;
2958         struct tcphdr *th, ttemp;
2959         int i_hlen, o_len;
2960         uint16_t port;
2961
2962         inner_ip = (struct ip *)vip;
2963         icmp = (struct icmp *)((caddr_t)inner_ip -
2964             (sizeof(struct icmp) - sizeof(struct ip)));
2965         outer_ip = (struct ip *)((caddr_t)icmp - sizeof(struct ip));
2966         i_hlen = inner_ip->ip_hl << 2;
2967         o_len = ntohs(outer_ip->ip_len);
2968         if (o_len <
2969             (sizeof(struct ip) + 8 + i_hlen + sizeof(struct udphdr) + offsetof(struct tcphdr, th_ack))) {
2970                 /* Not enough data present */
2971                 return;
2972         }
2973         /* Ok lets strip out the inner udphdr header by copying up on top of it the tcp hdr */
2974         udp = (struct udphdr *)(((caddr_t)inner_ip) + i_hlen);
2975         if (ntohs(udp->uh_sport) != V_tcp_udp_tunneling_port) {
2976                 return;
2977         }
2978         port = udp->uh_dport;
2979         th = (struct tcphdr *)(udp + 1);
2980         memcpy(&ttemp, th, sizeof(struct tcphdr));
2981         memcpy(udp, &ttemp, sizeof(struct tcphdr));
2982         /* Now adjust down the size of the outer IP header */
2983         o_len -= sizeof(struct udphdr);
2984         outer_ip->ip_len = htons(o_len);
2985         /* Now call in to the normal handling code */
2986         tcp_ctlinput_with_port(cmd, sa, vip, port);
2987 }
2988 #endif /* INET */
2989
2990 #ifdef INET6
2991 static inline int
2992 tcp6_next_pmtu(const struct icmp6_hdr *icmp6)
2993 {
2994         int mtu = ntohl(icmp6->icmp6_mtu);
2995
2996         /*
2997          * If no alternative MTU was proposed, or the proposed MTU was too
2998          * small, set to the min.
2999          */
3000         if (mtu < IPV6_MMTU)
3001                 mtu = IPV6_MMTU - 8;    /* XXXNP: what is the adjustment for? */
3002         return (mtu);
3003 }
3004
3005 static void
3006 tcp6_ctlinput_with_port(int cmd, struct sockaddr *sa, void *d, uint16_t port)
3007 {
3008         struct in6_addr *dst;
3009         struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
3010         struct ip6_hdr *ip6;
3011         struct mbuf *m;
3012         struct inpcb *inp;
3013         struct tcpcb *tp;
3014         struct icmp6_hdr *icmp6;
3015         struct ip6ctlparam *ip6cp = NULL;
3016         const struct sockaddr_in6 *sa6_src = NULL;
3017         struct in_conninfo inc;
3018         struct tcp_ports {
3019                 uint16_t th_sport;
3020                 uint16_t th_dport;
3021         } t_ports;
3022         tcp_seq icmp_tcp_seq;
3023         unsigned int mtu;
3024         unsigned int off;
3025
3026         if (sa->sa_family != AF_INET6 ||
3027             sa->sa_len != sizeof(struct sockaddr_in6))
3028                 return;
3029
3030         /* if the parameter is from icmp6, decode it. */
3031         if (d != NULL) {
3032                 ip6cp = (struct ip6ctlparam *)d;
3033                 icmp6 = ip6cp->ip6c_icmp6;
3034                 m = ip6cp->ip6c_m;
3035                 ip6 = ip6cp->ip6c_ip6;
3036                 off = ip6cp->ip6c_off;
3037                 sa6_src = ip6cp->ip6c_src;
3038                 dst = ip6cp->ip6c_finaldst;
3039         } else {
3040                 m = NULL;
3041                 ip6 = NULL;
3042                 off = 0;        /* fool gcc */
3043                 sa6_src = &sa6_any;
3044                 dst = NULL;
3045         }
3046
3047         if (cmd == PRC_MSGSIZE)
3048                 notify = tcp_mtudisc_notify;
3049         else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
3050                 cmd == PRC_UNREACH_PORT || cmd == PRC_UNREACH_PROTOCOL ||
3051                 cmd == PRC_TIMXCEED_INTRANS) && ip6 != NULL)
3052                 notify = tcp_drop_syn_sent;
3053
3054         /*
3055          * Hostdead is ugly because it goes linearly through all PCBs.
3056          * XXX: We never get this from ICMP, otherwise it makes an
3057          * excellent DoS attack on machines with many connections.
3058          */
3059         else if (cmd == PRC_HOSTDEAD)
3060                 ip6 = NULL;
3061         else if ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)
3062                 return;
3063
3064         if (ip6 == NULL) {
3065                 in6_pcbnotify(&V_tcbinfo, sa, 0,
3066                               (const struct sockaddr *)sa6_src,
3067                               0, cmd, NULL, notify);
3068                 return;
3069         }
3070
3071         /* Check if we can safely get the ports from the tcp hdr */
3072         if (m == NULL ||
3073             (m->m_pkthdr.len <
3074                 (int32_t) (off + sizeof(struct tcp_ports)))) {
3075                 return;
3076         }
3077         bzero(&t_ports, sizeof(struct tcp_ports));
3078         m_copydata(m, off, sizeof(struct tcp_ports), (caddr_t)&t_ports);
3079         inp = in6_pcblookup(&V_tcbinfo, &ip6->ip6_dst, t_ports.th_dport,
3080             &ip6->ip6_src, t_ports.th_sport, INPLOOKUP_WLOCKPCB, NULL);
3081         if (inp != NULL && PRC_IS_REDIRECT(cmd)) {
3082                 /* signal EHOSTDOWN, as it flushes the cached route */
3083                 inp = (*notify)(inp, EHOSTDOWN);
3084                 goto out;
3085         }
3086         off += sizeof(struct tcp_ports);
3087         if (m->m_pkthdr.len < (int32_t) (off + sizeof(tcp_seq))) {
3088                 goto out;
3089         }
3090         m_copydata(m, off, sizeof(tcp_seq), (caddr_t)&icmp_tcp_seq);
3091         if (inp != NULL)  {
3092                 if (!(inp->inp_flags & INP_TIMEWAIT) &&
3093                     !(inp->inp_flags & INP_DROPPED) &&
3094                     !(inp->inp_socket == NULL)) {
3095                         tp = intotcpcb(inp);
3096 #ifdef TCP_OFFLOAD
3097                         if (tp->t_flags & TF_TOE && cmd == PRC_MSGSIZE) {
3098                                 /* MTU discovery for offloaded connections. */
3099                                 mtu = tcp6_next_pmtu(icmp6);
3100                                 tcp_offload_pmtu_update(tp, icmp_tcp_seq, mtu);
3101                                 goto out;
3102                         }
3103 #endif
3104                         if (tp->t_port != port) {
3105                                 goto out;
3106                         }
3107                         if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
3108                             SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
3109                                 if (cmd == PRC_MSGSIZE) {
3110                                         /*
3111                                          * MTU discovery:
3112                                          * If we got a needfrag set the MTU
3113                                          * in the route to the suggested new
3114                                          * value (if given) and then notify.
3115                                          */
3116                                         mtu = tcp6_next_pmtu(icmp6);
3117
3118                                         bzero(&inc, sizeof(inc));
3119                                         inc.inc_fibnum = M_GETFIB(m);
3120                                         inc.inc_flags |= INC_ISIPV6;
3121                                         inc.inc6_faddr = *dst;
3122                                         if (in6_setscope(&inc.inc6_faddr,
3123                                                 m->m_pkthdr.rcvif, NULL))
3124                                                 goto out;
3125                                         /*
3126                                          * Only process the offered MTU if it
3127                                          * is smaller than the current one.
3128                                          */
3129                                         if (mtu < tp->t_maxseg +
3130                                             sizeof (struct tcphdr) +
3131                                             sizeof (struct ip6_hdr)) {
3132                                                 tcp_hc_updatemtu(&inc, mtu);
3133                                                 tcp_mtudisc(inp, mtu);
3134                                                 ICMP6STAT_INC(icp6s_pmtuchg);
3135                                         }
3136                                 } else
3137                                         inp = (*notify)(inp,
3138                                             inet6ctlerrmap[cmd]);
3139                         }
3140                 }
3141         } else {
3142                 bzero(&inc, sizeof(inc));
3143                 inc.inc_fibnum = M_GETFIB(m);
3144                 inc.inc_flags |= INC_ISIPV6;
3145                 inc.inc_fport = t_ports.th_dport;
3146                 inc.inc_lport = t_ports.th_sport;
3147                 inc.inc6_faddr = *dst;
3148                 inc.inc6_laddr = ip6->ip6_src;
3149                 syncache_unreach(&inc, icmp_tcp_seq, port);
3150         }
3151 out:
3152         if (inp != NULL)
3153                 INP_WUNLOCK(inp);
3154 }
3155
3156 void
3157 tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
3158 {
3159         tcp6_ctlinput_with_port(cmd, sa, d, htons(0));
3160 }
3161
3162 void
3163 tcp6_ctlinput_viaudp(int cmd, struct sockaddr *sa, void *d, void *unused)
3164 {
3165         struct ip6ctlparam *ip6cp;
3166         struct mbuf *m;
3167         struct udphdr *udp;
3168         uint16_t port;
3169
3170         ip6cp = (struct ip6ctlparam *)d;
3171         m = m_pulldown(ip6cp->ip6c_m, ip6cp->ip6c_off, sizeof(struct udphdr), NULL);
3172         if (m == NULL) {
3173                 return;
3174         }
3175         udp = mtod(m, struct udphdr *);
3176         if (ntohs(udp->uh_sport) != V_tcp_udp_tunneling_port) {
3177                 return;
3178         }
3179         port = udp->uh_dport;
3180         m_adj(m, sizeof(struct udphdr));
3181         if ((m->m_flags & M_PKTHDR) == 0) {
3182                 ip6cp->ip6c_m->m_pkthdr.len -= sizeof(struct udphdr);
3183         }
3184         /* Now call in to the normal handling code */
3185         tcp6_ctlinput_with_port(cmd, sa, d, port);
3186 }
3187
3188 #endif /* INET6 */
3189
3190 static uint32_t
3191 tcp_keyed_hash(struct in_conninfo *inc, u_char *key, u_int len)
3192 {
3193         SIPHASH_CTX ctx;
3194         uint32_t hash[2];
3195
3196         KASSERT(len >= SIPHASH_KEY_LENGTH,
3197             ("%s: keylen %u too short ", __func__, len));
3198         SipHash24_Init(&ctx);
3199         SipHash_SetKey(&ctx, (uint8_t *)key);
3200         SipHash_Update(&ctx, &inc->inc_fport, sizeof(uint16_t));
3201         SipHash_Update(&ctx, &inc->inc_lport, sizeof(uint16_t));
3202         switch (inc->inc_flags & INC_ISIPV6) {
3203 #ifdef INET
3204         case 0:
3205                 SipHash_Update(&ctx, &inc->inc_faddr, sizeof(struct in_addr));
3206                 SipHash_Update(&ctx, &inc->inc_laddr, sizeof(struct in_addr));
3207                 break;
3208 #endif
3209 #ifdef INET6
3210         case INC_ISIPV6:
3211                 SipHash_Update(&ctx, &inc->inc6_faddr, sizeof(struct in6_addr));
3212                 SipHash_Update(&ctx, &inc->inc6_laddr, sizeof(struct in6_addr));
3213                 break;
3214 #endif
3215         }
3216         SipHash_Final((uint8_t *)hash, &ctx);
3217
3218         return (hash[0] ^ hash[1]);
3219 }
3220
3221 uint32_t
3222 tcp_new_ts_offset(struct in_conninfo *inc)
3223 {
3224         struct in_conninfo inc_store, *local_inc;
3225
3226         if (!V_tcp_ts_offset_per_conn) {
3227                 memcpy(&inc_store, inc, sizeof(struct in_conninfo));
3228                 inc_store.inc_lport = 0;
3229                 inc_store.inc_fport = 0;
3230                 local_inc = &inc_store;
3231         } else {
3232                 local_inc = inc;
3233         }
3234         return (tcp_keyed_hash(local_inc, V_ts_offset_secret,
3235             sizeof(V_ts_offset_secret)));
3236 }
3237
3238 /*
3239  * Following is where TCP initial sequence number generation occurs.
3240  *
3241  * There are two places where we must use initial sequence numbers:
3242  * 1.  In SYN-ACK packets.
3243  * 2.  In SYN packets.
3244  *
3245  * All ISNs for SYN-ACK packets are generated by the syncache.  See
3246  * tcp_syncache.c for details.
3247  *
3248  * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
3249  * depends on this property.  In addition, these ISNs should be
3250  * unguessable so as to prevent connection hijacking.  To satisfy
3251  * the requirements of this situation, the algorithm outlined in
3252  * RFC 1948 is used, with only small modifications.
3253  *
3254  * Implementation details:
3255  *
3256  * Time is based off the system timer, and is corrected so that it
3257  * increases by one megabyte per second.  This allows for proper
3258  * recycling on high speed LANs while still leaving over an hour
3259  * before rollover.
3260  *
3261  * As reading the *exact* system time is too expensive to be done
3262  * whenever setting up a TCP connection, we increment the time
3263  * offset in two ways.  First, a small random positive increment
3264  * is added to isn_offset for each connection that is set up.
3265  * Second, the function tcp_isn_tick fires once per clock tick
3266  * and increments isn_offset as necessary so that sequence numbers
3267  * are incremented at approximately ISN_BYTES_PER_SECOND.  The
3268  * random positive increments serve only to ensure that the same
3269  * exact sequence number is never sent out twice (as could otherwise
3270  * happen when a port is recycled in less than the system tick
3271  * interval.)
3272  *
3273  * net.inet.tcp.isn_reseed_interval controls the number of seconds
3274  * between seeding of isn_secret.  This is normally set to zero,
3275  * as reseeding should not be necessary.
3276  *
3277  * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
3278  * isn_offset_old, and isn_ctx is performed using the ISN lock.  In
3279  * general, this means holding an exclusive (write) lock.
3280  */
3281
3282 #define ISN_BYTES_PER_SECOND 1048576
3283 #define ISN_STATIC_INCREMENT 4096
3284 #define ISN_RANDOM_INCREMENT (4096 - 1)
3285 #define ISN_SECRET_LENGTH    SIPHASH_KEY_LENGTH
3286
3287 VNET_DEFINE_STATIC(u_char, isn_secret[ISN_SECRET_LENGTH]);
3288 VNET_DEFINE_STATIC(int, isn_last);
3289 VNET_DEFINE_STATIC(int, isn_last_reseed);
3290 VNET_DEFINE_STATIC(u_int32_t, isn_offset);
3291 VNET_DEFINE_STATIC(u_int32_t, isn_offset_old);
3292
3293 #define V_isn_secret                    VNET(isn_secret)
3294 #define V_isn_last                      VNET(isn_last)
3295 #define V_isn_last_reseed               VNET(isn_last_reseed)
3296 #define V_isn_offset                    VNET(isn_offset)
3297 #define V_isn_offset_old                VNET(isn_offset_old)
3298
3299 tcp_seq
3300 tcp_new_isn(struct in_conninfo *inc)
3301 {
3302         tcp_seq new_isn;
3303         u_int32_t projected_offset;
3304
3305         ISN_LOCK();
3306         /* Seed if this is the first use, reseed if requested. */
3307         if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) &&
3308              (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz)
3309                 < (u_int)ticks))) {
3310                 arc4rand(&V_isn_secret, sizeof(V_isn_secret), 0);
3311                 V_isn_last_reseed = ticks;
3312         }
3313
3314         /* Compute the hash and return the ISN. */
3315         new_isn = (tcp_seq)tcp_keyed_hash(inc, V_isn_secret,
3316             sizeof(V_isn_secret));
3317         V_isn_offset += ISN_STATIC_INCREMENT +
3318                 (arc4random() & ISN_RANDOM_INCREMENT);
3319         if (ticks != V_isn_last) {
3320                 projected_offset = V_isn_offset_old +
3321                     ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last);
3322                 if (SEQ_GT(projected_offset, V_isn_offset))
3323                         V_isn_offset = projected_offset;
3324                 V_isn_offset_old = V_isn_offset;
3325                 V_isn_last = ticks;
3326         }
3327         new_isn += V_isn_offset;
3328         ISN_UNLOCK();
3329         return (new_isn);
3330 }
3331
3332 /*
3333  * When a specific ICMP unreachable message is received and the
3334  * connection state is SYN-SENT, drop the connection.  This behavior
3335  * is controlled by the icmp_may_rst sysctl.
3336  */
3337 struct inpcb *
3338 tcp_drop_syn_sent(struct inpcb *inp, int errno)
3339 {
3340         struct tcpcb *tp;
3341
3342         NET_EPOCH_ASSERT();
3343         INP_WLOCK_ASSERT(inp);
3344
3345         if ((inp->inp_flags & INP_TIMEWAIT) ||
3346             (inp->inp_flags & INP_DROPPED))
3347                 return (inp);
3348
3349         tp = intotcpcb(inp);
3350         if (tp->t_state != TCPS_SYN_SENT)
3351                 return (inp);
3352
3353         if (IS_FASTOPEN(tp->t_flags))
3354                 tcp_fastopen_disable_path(tp);
3355
3356         tp = tcp_drop(tp, errno);
3357         if (tp != NULL)
3358                 return (inp);
3359         else
3360                 return (NULL);
3361 }
3362
3363 /*
3364  * When `need fragmentation' ICMP is received, update our idea of the MSS
3365  * based on the new value. Also nudge TCP to send something, since we
3366  * know the packet we just sent was dropped.
3367  * This duplicates some code in the tcp_mss() function in tcp_input.c.
3368  */
3369 static struct inpcb *
3370 tcp_mtudisc_notify(struct inpcb *inp, int error)
3371 {
3372
3373         return (tcp_mtudisc(inp, -1));
3374 }
3375
3376 static struct inpcb *
3377 tcp_mtudisc(struct inpcb *inp, int mtuoffer)
3378 {
3379         struct tcpcb *tp;
3380         struct socket *so;
3381
3382         INP_WLOCK_ASSERT(inp);
3383         if ((inp->inp_flags & INP_TIMEWAIT) ||
3384             (inp->inp_flags & INP_DROPPED))
3385                 return (inp);
3386
3387         tp = intotcpcb(inp);
3388         KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
3389
3390         tcp_mss_update(tp, -1, mtuoffer, NULL, NULL);
3391
3392         so = inp->inp_socket;
3393         SOCKBUF_LOCK(&so->so_snd);
3394         /* If the mss is larger than the socket buffer, decrease the mss. */
3395         if (so->so_snd.sb_hiwat < tp->t_maxseg)
3396                 tp->t_maxseg = so->so_snd.sb_hiwat;
3397         SOCKBUF_UNLOCK(&so->so_snd);
3398
3399         TCPSTAT_INC(tcps_mturesent);
3400         tp->t_rtttime = 0;
3401         tp->snd_nxt = tp->snd_una;
3402         tcp_free_sackholes(tp);
3403         tp->snd_recover = tp->snd_max;
3404         if (tp->t_flags & TF_SACK_PERMIT)
3405                 EXIT_FASTRECOVERY(tp->t_flags);
3406         if (tp->t_fb->tfb_tcp_mtu_chg != NULL) {
3407                 /*
3408                  * Conceptually the snd_nxt setting
3409                  * and freeing sack holes should
3410                  * be done by the default stacks
3411                  * own tfb_tcp_mtu_chg().
3412                  */
3413                 tp->t_fb->tfb_tcp_mtu_chg(tp);
3414         }
3415         if (tcp_output(tp) < 0)
3416                 return (NULL);
3417         else
3418                 return (inp);
3419 }
3420
3421 #ifdef INET
3422 /*
3423  * Look-up the routing entry to the peer of this inpcb.  If no route
3424  * is found and it cannot be allocated, then return 0.  This routine
3425  * is called by TCP routines that access the rmx structure and by
3426  * tcp_mss_update to get the peer/interface MTU.
3427  */
3428 uint32_t
3429 tcp_maxmtu(struct in_conninfo *inc, struct tcp_ifcap *cap)
3430 {
3431         struct nhop_object *nh;
3432         struct ifnet *ifp;
3433         uint32_t maxmtu = 0;
3434
3435         KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
3436
3437         if (inc->inc_faddr.s_addr != INADDR_ANY) {
3438                 nh = fib4_lookup(inc->inc_fibnum, inc->inc_faddr, 0, NHR_NONE, 0);
3439                 if (nh == NULL)
3440                         return (0);
3441
3442                 ifp = nh->nh_ifp;
3443                 maxmtu = nh->nh_mtu;
3444
3445                 /* Report additional interface capabilities. */
3446                 if (cap != NULL) {
3447                         if (ifp->if_capenable & IFCAP_TSO4 &&
3448                             ifp->if_hwassist & CSUM_TSO) {
3449                                 cap->ifcap |= CSUM_TSO;
3450                                 cap->tsomax = ifp->if_hw_tsomax;
3451                                 cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
3452                                 cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
3453                         }
3454                 }
3455         }
3456         return (maxmtu);
3457 }
3458 #endif /* INET */
3459
3460 #ifdef INET6
3461 uint32_t
3462 tcp_maxmtu6(struct in_conninfo *inc, struct tcp_ifcap *cap)
3463 {
3464         struct nhop_object *nh;
3465         struct in6_addr dst6;
3466         uint32_t scopeid;
3467         struct ifnet *ifp;
3468         uint32_t maxmtu = 0;
3469
3470         KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
3471
3472         if (inc->inc_flags & INC_IPV6MINMTU)
3473                 return (IPV6_MMTU);
3474
3475         if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
3476                 in6_splitscope(&inc->inc6_faddr, &dst6, &scopeid);
3477                 nh = fib6_lookup(inc->inc_fibnum, &dst6, scopeid, NHR_NONE, 0);
3478                 if (nh == NULL)
3479                         return (0);
3480
3481                 ifp = nh->nh_ifp;
3482                 maxmtu = nh->nh_mtu;
3483
3484                 /* Report additional interface capabilities. */
3485                 if (cap != NULL) {
3486                         if (ifp->if_capenable & IFCAP_TSO6 &&
3487                             ifp->if_hwassist & CSUM_TSO) {
3488                                 cap->ifcap |= CSUM_TSO;
3489                                 cap->tsomax = ifp->if_hw_tsomax;
3490                                 cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
3491                                 cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
3492                         }
3493                 }
3494         }
3495
3496         return (maxmtu);
3497 }
3498
3499 /*
3500  * Handle setsockopt(IPV6_USE_MIN_MTU) by a TCP stack.
3501  *
3502  * XXXGL: we are updating inpcb here with INC_IPV6MINMTU flag.
3503  * The right place to do that is ip6_setpktopt() that has just been
3504  * executed.  By the way it just filled ip6po_minmtu for us.
3505  */
3506 void
3507 tcp6_use_min_mtu(struct tcpcb *tp)
3508 {
3509         struct inpcb *inp = tp->t_inpcb;
3510
3511         INP_WLOCK_ASSERT(inp);
3512         /*
3513          * In case of the IPV6_USE_MIN_MTU socket
3514          * option, the INC_IPV6MINMTU flag to announce
3515          * a corresponding MSS during the initial
3516          * handshake.  If the TCP connection is not in
3517          * the front states, just reduce the MSS being
3518          * used.  This avoids the sending of TCP
3519          * segments which will be fragmented at the
3520          * IPv6 layer.
3521          */
3522         inp->inp_inc.inc_flags |= INC_IPV6MINMTU;
3523         if ((tp->t_state >= TCPS_SYN_SENT) &&
3524             (inp->inp_inc.inc_flags & INC_ISIPV6)) {
3525                 struct ip6_pktopts *opt;
3526
3527                 opt = inp->in6p_outputopts;
3528                 if (opt != NULL && opt->ip6po_minmtu == IP6PO_MINMTU_ALL &&
3529                     tp->t_maxseg > TCP6_MSS)
3530                         tp->t_maxseg = TCP6_MSS;
3531         }
3532 }
3533 #endif /* INET6 */
3534
3535 /*
3536  * Calculate effective SMSS per RFC5681 definition for a given TCP
3537  * connection at its current state, taking into account SACK and etc.
3538  */
3539 u_int
3540 tcp_maxseg(const struct tcpcb *tp)
3541 {
3542         u_int optlen;
3543
3544         if (tp->t_flags & TF_NOOPT)
3545                 return (tp->t_maxseg);
3546
3547         /*
3548          * Here we have a simplified code from tcp_addoptions(),
3549          * without a proper loop, and having most of paddings hardcoded.
3550          * We might make mistakes with padding here in some edge cases,
3551          * but this is harmless, since result of tcp_maxseg() is used
3552          * only in cwnd and ssthresh estimations.
3553          */
3554         if (TCPS_HAVEESTABLISHED(tp->t_state)) {
3555                 if (tp->t_flags & TF_RCVD_TSTMP)
3556                         optlen = TCPOLEN_TSTAMP_APPA;
3557                 else
3558                         optlen = 0;
3559 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
3560                 if (tp->t_flags & TF_SIGNATURE)
3561                         optlen += PADTCPOLEN(TCPOLEN_SIGNATURE);
3562 #endif
3563                 if ((tp->t_flags & TF_SACK_PERMIT) && tp->rcv_numsacks > 0) {
3564                         optlen += TCPOLEN_SACKHDR;
3565                         optlen += tp->rcv_numsacks * TCPOLEN_SACK;
3566                         optlen = PADTCPOLEN(optlen);
3567                 }
3568         } else {
3569                 if (tp->t_flags & TF_REQ_TSTMP)
3570                         optlen = TCPOLEN_TSTAMP_APPA;
3571                 else
3572                         optlen = PADTCPOLEN(TCPOLEN_MAXSEG);
3573                 if (tp->t_flags & TF_REQ_SCALE)
3574                         optlen += PADTCPOLEN(TCPOLEN_WINDOW);
3575 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
3576                 if (tp->t_flags & TF_SIGNATURE)
3577                         optlen += PADTCPOLEN(TCPOLEN_SIGNATURE);
3578 #endif
3579                 if (tp->t_flags & TF_SACK_PERMIT)
3580                         optlen += PADTCPOLEN(TCPOLEN_SACK_PERMITTED);
3581         }
3582 #undef PAD
3583         optlen = min(optlen, TCP_MAXOLEN);
3584         return (tp->t_maxseg - optlen);
3585 }
3586
3587
3588 u_int
3589 tcp_fixed_maxseg(const struct tcpcb *tp)
3590 {
3591         int optlen;
3592
3593         if (tp->t_flags & TF_NOOPT)
3594                 return (tp->t_maxseg);
3595
3596         /*
3597          * Here we have a simplified code from tcp_addoptions(),
3598          * without a proper loop, and having most of paddings hardcoded.
3599          * We only consider fixed options that we would send every
3600          * time I.e. SACK is not considered. This is important
3601          * for cc modules to figure out what the modulo of the
3602          * cwnd should be.
3603          */
3604 #define PAD(len)        ((((len) / 4) + !!((len) % 4)) * 4)
3605         if (TCPS_HAVEESTABLISHED(tp->t_state)) {
3606                 if (tp->t_flags & TF_RCVD_TSTMP)
3607                         optlen = TCPOLEN_TSTAMP_APPA;
3608                 else
3609                         optlen = 0;
3610 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
3611                 if (tp->t_flags & TF_SIGNATURE)
3612                         optlen += PAD(TCPOLEN_SIGNATURE);
3613 #endif
3614         } else {
3615                 if (tp->t_flags & TF_REQ_TSTMP)
3616                         optlen = TCPOLEN_TSTAMP_APPA;
3617                 else
3618                         optlen = PAD(TCPOLEN_MAXSEG);
3619                 if (tp->t_flags & TF_REQ_SCALE)
3620                         optlen += PAD(TCPOLEN_WINDOW);
3621 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
3622                 if (tp->t_flags & TF_SIGNATURE)
3623                         optlen += PAD(TCPOLEN_SIGNATURE);
3624 #endif
3625                 if (tp->t_flags & TF_SACK_PERMIT)
3626                         optlen += PAD(TCPOLEN_SACK_PERMITTED);
3627         }
3628 #undef PAD
3629         optlen = min(optlen, TCP_MAXOLEN);
3630         return (tp->t_maxseg - optlen);
3631 }
3632
3633
3634
3635 static int
3636 sysctl_drop(SYSCTL_HANDLER_ARGS)
3637 {
3638         /* addrs[0] is a foreign socket, addrs[1] is a local one. */
3639         struct sockaddr_storage addrs[2];
3640         struct inpcb *inp;
3641         struct tcpcb *tp;
3642         struct tcptw *tw;
3643 #ifdef INET
3644         struct sockaddr_in *fin = NULL, *lin = NULL;
3645 #endif
3646         struct epoch_tracker et;
3647 #ifdef INET6
3648         struct sockaddr_in6 *fin6, *lin6;
3649 #endif
3650         int error;
3651
3652         inp = NULL;
3653 #ifdef INET6
3654         fin6 = lin6 = NULL;
3655 #endif
3656         error = 0;
3657
3658         if (req->oldptr != NULL || req->oldlen != 0)
3659                 return (EINVAL);
3660         if (req->newptr == NULL)
3661                 return (EPERM);
3662         if (req->newlen < sizeof(addrs))
3663                 return (ENOMEM);
3664         error = SYSCTL_IN(req, &addrs, sizeof(addrs));
3665         if (error)
3666                 return (error);
3667
3668         switch (addrs[0].ss_family) {
3669 #ifdef INET6
3670         case AF_INET6:
3671                 fin6 = (struct sockaddr_in6 *)&addrs[0];
3672                 lin6 = (struct sockaddr_in6 *)&addrs[1];
3673                 if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
3674                     lin6->sin6_len != sizeof(struct sockaddr_in6))
3675                         return (EINVAL);
3676                 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
3677                         if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
3678                                 return (EINVAL);
3679                         in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
3680                         in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
3681 #ifdef INET
3682                         fin = (struct sockaddr_in *)&addrs[0];
3683                         lin = (struct sockaddr_in *)&addrs[1];
3684 #endif
3685                         break;
3686                 }
3687                 error = sa6_embedscope(fin6, V_ip6_use_defzone);
3688                 if (error)
3689                         return (error);
3690                 error = sa6_embedscope(lin6, V_ip6_use_defzone);
3691                 if (error)
3692                         return (error);
3693                 break;
3694 #endif
3695 #ifdef INET
3696         case AF_INET:
3697                 fin = (struct sockaddr_in *)&addrs[0];
3698                 lin = (struct sockaddr_in *)&addrs[1];
3699                 if (fin->sin_len != sizeof(struct sockaddr_in) ||
3700                     lin->sin_len != sizeof(struct sockaddr_in))
3701                         return (EINVAL);
3702                 break;
3703 #endif
3704         default:
3705                 return (EINVAL);
3706         }
3707         NET_EPOCH_ENTER(et);
3708         switch (addrs[0].ss_family) {
3709 #ifdef INET6
3710         case AF_INET6:
3711                 inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
3712                     fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
3713                     INPLOOKUP_WLOCKPCB, NULL);
3714                 break;
3715 #endif
3716 #ifdef INET
3717         case AF_INET:
3718                 inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
3719                     lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
3720                 break;
3721 #endif
3722         }
3723         if (inp != NULL) {
3724                 if (inp->inp_flags & INP_TIMEWAIT) {
3725                         /*
3726                          * XXXRW: There currently exists a state where an
3727                          * inpcb is present, but its timewait state has been
3728                          * discarded.  For now, don't allow dropping of this
3729                          * type of inpcb.
3730                          */
3731                         tw = intotw(inp);
3732                         if (tw != NULL)
3733                                 tcp_twclose(tw, 0);
3734                         else
3735                                 INP_WUNLOCK(inp);
3736                 } else if ((inp->inp_flags & INP_DROPPED) == 0 &&
3737                     !SOLISTENING(inp->inp_socket)) {
3738                         tp = intotcpcb(inp);
3739                         tp = tcp_drop(tp, ECONNABORTED);
3740                         if (tp != NULL)
3741                                 INP_WUNLOCK(inp);
3742                 } else
3743                         INP_WUNLOCK(inp);
3744         } else
3745                 error = ESRCH;
3746         NET_EPOCH_EXIT(et);
3747         return (error);
3748 }
3749
3750 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
3751     CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
3752     CTLFLAG_NEEDGIANT, NULL, 0, sysctl_drop, "",
3753     "Drop TCP connection");
3754
3755 static int
3756 tcp_sysctl_setsockopt(SYSCTL_HANDLER_ARGS)
3757 {
3758         return (sysctl_setsockopt(oidp, arg1, arg2, req, &V_tcbinfo,
3759             &tcp_ctloutput_set));
3760 }
3761
3762 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, setsockopt,
3763     CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
3764     CTLFLAG_MPSAFE, NULL, 0, tcp_sysctl_setsockopt, "",
3765     "Set socket option for TCP endpoint");
3766
3767 #ifdef KERN_TLS
3768 static int
3769 sysctl_switch_tls(SYSCTL_HANDLER_ARGS)
3770 {
3771         /* addrs[0] is a foreign socket, addrs[1] is a local one. */
3772         struct sockaddr_storage addrs[2];
3773         struct inpcb *inp;
3774 #ifdef INET
3775         struct sockaddr_in *fin = NULL, *lin = NULL;
3776 #endif
3777         struct epoch_tracker et;
3778 #ifdef INET6
3779         struct sockaddr_in6 *fin6, *lin6;
3780 #endif
3781         int error;
3782
3783         inp = NULL;
3784 #ifdef INET6
3785         fin6 = lin6 = NULL;
3786 #endif
3787         error = 0;
3788
3789         if (req->oldptr != NULL || req->oldlen != 0)
3790                 return (EINVAL);
3791         if (req->newptr == NULL)
3792                 return (EPERM);
3793         if (req->newlen < sizeof(addrs))
3794                 return (ENOMEM);
3795         error = SYSCTL_IN(req, &addrs, sizeof(addrs));
3796         if (error)
3797                 return (error);
3798
3799         switch (addrs[0].ss_family) {
3800 #ifdef INET6
3801         case AF_INET6:
3802                 fin6 = (struct sockaddr_in6 *)&addrs[0];
3803                 lin6 = (struct sockaddr_in6 *)&addrs[1];
3804                 if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
3805                     lin6->sin6_len != sizeof(struct sockaddr_in6))
3806                         return (EINVAL);
3807                 if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
3808                         if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
3809                                 return (EINVAL);
3810                         in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
3811                         in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
3812 #ifdef INET
3813                         fin = (struct sockaddr_in *)&addrs[0];
3814                         lin = (struct sockaddr_in *)&addrs[1];
3815 #endif
3816                         break;
3817                 }
3818                 error = sa6_embedscope(fin6, V_ip6_use_defzone);
3819                 if (error)
3820                         return (error);
3821                 error = sa6_embedscope(lin6, V_ip6_use_defzone);
3822                 if (error)
3823                         return (error);
3824                 break;
3825 #endif
3826 #ifdef INET
3827         case AF_INET:
3828                 fin = (struct sockaddr_in *)&addrs[0];
3829                 lin = (struct sockaddr_in *)&addrs[1];
3830                 if (fin->sin_len != sizeof(struct sockaddr_in) ||
3831                     lin->sin_len != sizeof(struct sockaddr_in))
3832                         return (EINVAL);
3833                 break;
3834 #endif
3835         default:
3836                 return (EINVAL);
3837         }
3838         NET_EPOCH_ENTER(et);
3839         switch (addrs[0].ss_family) {
3840 #ifdef INET6
3841         case AF_INET6:
3842                 inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
3843                     fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
3844                     INPLOOKUP_WLOCKPCB, NULL);
3845                 break;
3846 #endif
3847 #ifdef INET
3848         case AF_INET:
3849                 inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
3850                     lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
3851                 break;
3852 #endif
3853         }
3854         NET_EPOCH_EXIT(et);
3855         if (inp != NULL) {
3856                 if ((inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) != 0 ||
3857                     inp->inp_socket == NULL) {
3858                         error = ECONNRESET;
3859                         INP_WUNLOCK(inp);
3860                 } else {
3861                         struct socket *so;
3862
3863                         so = inp->inp_socket;
3864                         soref(so);
3865                         error = ktls_set_tx_mode(so,
3866                             arg2 == 0 ? TCP_TLS_MODE_SW : TCP_TLS_MODE_IFNET);
3867                         INP_WUNLOCK(inp);
3868                         sorele(so);
3869                 }
3870         } else
3871                 error = ESRCH;
3872         return (error);
3873 }
3874
3875 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, switch_to_sw_tls,
3876     CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
3877     CTLFLAG_NEEDGIANT, NULL, 0, sysctl_switch_tls, "",
3878     "Switch TCP connection to SW TLS");
3879 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, switch_to_ifnet_tls,
3880     CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
3881     CTLFLAG_NEEDGIANT, NULL, 1, sysctl_switch_tls, "",
3882     "Switch TCP connection to ifnet TLS");
3883 #endif
3884
3885 /*
3886  * Generate a standardized TCP log line for use throughout the
3887  * tcp subsystem.  Memory allocation is done with M_NOWAIT to
3888  * allow use in the interrupt context.
3889  *
3890  * NB: The caller MUST free(s, M_TCPLOG) the returned string.
3891  * NB: The function may return NULL if memory allocation failed.
3892  *
3893  * Due to header inclusion and ordering limitations the struct ip
3894  * and ip6_hdr pointers have to be passed as void pointers.
3895  */
3896 char *
3897 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, const void *ip4hdr,
3898     const void *ip6hdr)
3899 {
3900
3901         /* Is logging enabled? */
3902         if (V_tcp_log_in_vain == 0)
3903                 return (NULL);
3904
3905         return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
3906 }
3907
3908 char *
3909 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, const void *ip4hdr,
3910     const void *ip6hdr)
3911 {
3912
3913         /* Is logging enabled? */
3914         if (tcp_log_debug == 0)
3915                 return (NULL);
3916
3917         return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
3918 }
3919
3920 static char *
3921 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, const void *ip4hdr,
3922     const void *ip6hdr)
3923 {
3924         char *s, *sp;
3925         size_t size;
3926 #ifdef INET
3927         const struct ip *ip = (const struct ip *)ip4hdr;
3928 #endif
3929 #ifdef INET6
3930         const struct ip6_hdr *ip6 = (const struct ip6_hdr *)ip6hdr;
3931 #endif /* INET6 */
3932
3933         /*
3934          * The log line looks like this:
3935          * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>"
3936          */
3937         size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") +
3938             sizeof(PRINT_TH_FLAGS) + 1 +
3939 #ifdef INET6
3940             2 * INET6_ADDRSTRLEN;
3941 #else
3942             2 * INET_ADDRSTRLEN;
3943 #endif /* INET6 */
3944
3945         s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT);
3946         if (s == NULL)
3947                 return (NULL);
3948
3949         strcat(s, "TCP: [");
3950         sp = s + strlen(s);
3951
3952         if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) {
3953                 inet_ntoa_r(inc->inc_faddr, sp);
3954                 sp = s + strlen(s);
3955                 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
3956                 sp = s + strlen(s);
3957                 inet_ntoa_r(inc->inc_laddr, sp);
3958                 sp = s + strlen(s);
3959                 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
3960 #ifdef INET6
3961         } else if (inc) {
3962                 ip6_sprintf(sp, &inc->inc6_faddr);
3963                 sp = s + strlen(s);
3964                 sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
3965                 sp = s + strlen(s);
3966                 ip6_sprintf(sp, &inc->inc6_laddr);
3967                 sp = s + strlen(s);
3968                 sprintf(sp, "]:%i", ntohs(inc->inc_lport));
3969         } else if (ip6 && th) {
3970                 ip6_sprintf(sp, &ip6->ip6_src);
3971                 sp = s + strlen(s);
3972                 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
3973                 sp = s + strlen(s);
3974                 ip6_sprintf(sp, &ip6->ip6_dst);
3975                 sp = s + strlen(s);
3976                 sprintf(sp, "]:%i", ntohs(th->th_dport));
3977 #endif /* INET6 */
3978 #ifdef INET
3979         } else if (ip && th) {
3980                 inet_ntoa_r(ip->ip_src, sp);
3981                 sp = s + strlen(s);
3982                 sprintf(sp, "]:%i to [", ntohs(th->th_sport));
3983                 sp = s + strlen(s);
3984                 inet_ntoa_r(ip->ip_dst, sp);
3985                 sp = s + strlen(s);
3986                 sprintf(sp, "]:%i", ntohs(th->th_dport));
3987 #endif /* INET */
3988         } else {
3989                 free(s, M_TCPLOG);
3990                 return (NULL);
3991         }
3992         sp = s + strlen(s);
3993         if (th)
3994                 sprintf(sp, " tcpflags 0x%b", tcp_get_flags(th), PRINT_TH_FLAGS);
3995         if (*(s + size - 1) != '\0')
3996                 panic("%s: string too long", __func__);
3997         return (s);
3998 }
3999
4000 /*
4001  * A subroutine which makes it easy to track TCP state changes with DTrace.
4002  * This function shouldn't be called for t_state initializations that don't
4003  * correspond to actual TCP state transitions.
4004  */
4005 void
4006 tcp_state_change(struct tcpcb *tp, int newstate)
4007 {
4008 #if defined(KDTRACE_HOOKS)
4009         int pstate = tp->t_state;
4010 #endif
4011
4012         TCPSTATES_DEC(tp->t_state);
4013         TCPSTATES_INC(newstate);
4014         tp->t_state = newstate;
4015         TCP_PROBE6(state__change, NULL, tp, NULL, tp, NULL, pstate);
4016 }
4017
4018 /*
4019  * Create an external-format (``xtcpcb'') structure using the information in
4020  * the kernel-format tcpcb structure pointed to by tp.  This is done to
4021  * reduce the spew of irrelevant information over this interface, to isolate
4022  * user code from changes in the kernel structure, and potentially to provide
4023  * information-hiding if we decide that some of this information should be
4024  * hidden from users.
4025  */
4026 void
4027 tcp_inptoxtp(const struct inpcb *inp, struct xtcpcb *xt)
4028 {
4029         struct tcpcb *tp = intotcpcb(inp);
4030         struct tcptw *tw = intotw(inp);
4031         sbintime_t now;
4032
4033         bzero(xt, sizeof(*xt));
4034         if (inp->inp_flags & INP_TIMEWAIT) {
4035                 xt->t_state = TCPS_TIME_WAIT;
4036                 xt->xt_encaps_port = tw->t_port;
4037         } else {
4038                 xt->t_state = tp->t_state;
4039                 xt->t_logstate = tp->t_logstate;
4040                 xt->t_flags = tp->t_flags;
4041                 xt->t_sndzerowin = tp->t_sndzerowin;
4042                 xt->t_sndrexmitpack = tp->t_sndrexmitpack;
4043                 xt->t_rcvoopack = tp->t_rcvoopack;
4044                 xt->t_rcv_wnd = tp->rcv_wnd;
4045                 xt->t_snd_wnd = tp->snd_wnd;
4046                 xt->t_snd_cwnd = tp->snd_cwnd;
4047                 xt->t_snd_ssthresh = tp->snd_ssthresh;
4048                 xt->t_dsack_bytes = tp->t_dsack_bytes;
4049                 xt->t_dsack_tlp_bytes = tp->t_dsack_tlp_bytes;
4050                 xt->t_dsack_pack = tp->t_dsack_pack;
4051                 xt->t_maxseg = tp->t_maxseg;
4052                 xt->xt_ecn = (tp->t_flags2 & TF2_ECN_PERMIT) ? 1 : 0 +
4053                              (tp->t_flags2 & TF2_ACE_PERMIT) ? 2 : 0;
4054
4055                 now = getsbinuptime();
4056 #define COPYTIMER(ttt)  do {                                            \
4057                 if (callout_active(&tp->t_timers->ttt))                 \
4058                         xt->ttt = (tp->t_timers->ttt.c_time - now) /    \
4059                             SBT_1MS;                                    \
4060                 else                                                    \
4061                         xt->ttt = 0;                                    \
4062 } while (0)
4063                 COPYTIMER(tt_delack);
4064                 COPYTIMER(tt_rexmt);
4065                 COPYTIMER(tt_persist);
4066                 COPYTIMER(tt_keep);
4067                 COPYTIMER(tt_2msl);
4068 #undef COPYTIMER
4069                 xt->t_rcvtime = 1000 * (ticks - tp->t_rcvtime) / hz;
4070
4071                 xt->xt_encaps_port = tp->t_port;
4072                 bcopy(tp->t_fb->tfb_tcp_block_name, xt->xt_stack,
4073                     TCP_FUNCTION_NAME_LEN_MAX);
4074                 bcopy(CC_ALGO(tp)->name, xt->xt_cc,
4075                     TCP_CA_NAME_MAX);
4076 #ifdef TCP_BLACKBOX
4077                 (void)tcp_log_get_id(tp, xt->xt_logid);
4078 #endif
4079         }
4080
4081         xt->xt_len = sizeof(struct xtcpcb);
4082         in_pcbtoxinpcb(inp, &xt->xt_inp);
4083         if (inp->inp_socket == NULL)
4084                 xt->xt_inp.xi_socket.xso_protocol = IPPROTO_TCP;
4085 }
4086
4087 void
4088 tcp_log_end_status(struct tcpcb *tp, uint8_t status)
4089 {
4090         uint32_t bit, i;
4091
4092         if ((tp == NULL) ||
4093             (status > TCP_EI_STATUS_MAX_VALUE) ||
4094             (status == 0)) {
4095                 /* Invalid */
4096                 return;
4097         }
4098         if (status > (sizeof(uint32_t) * 8)) {
4099                 /* Should this be a KASSERT? */
4100                 return;
4101         }
4102         bit = 1U << (status - 1);
4103         if (bit & tp->t_end_info_status) {
4104                 /* already logged */
4105                 return;
4106         }
4107         for (i = 0; i < TCP_END_BYTE_INFO; i++) {
4108                 if (tp->t_end_info_bytes[i] == TCP_EI_EMPTY_SLOT) {
4109                         tp->t_end_info_bytes[i] = status;
4110                         tp->t_end_info_status |= bit;
4111                         break;
4112                 }
4113         }
4114 }
4115
4116 int
4117 tcp_can_enable_pacing(void)
4118 {
4119
4120         if ((tcp_pacing_limit == -1) ||
4121             (tcp_pacing_limit > number_of_tcp_connections_pacing)) {
4122                 atomic_fetchadd_int(&number_of_tcp_connections_pacing, 1);
4123                 shadow_num_connections = number_of_tcp_connections_pacing;
4124                 return (1);
4125         } else {
4126                 return (0);
4127         }
4128 }
4129
4130 static uint8_t tcp_pacing_warning = 0;
4131
4132 void
4133 tcp_decrement_paced_conn(void)
4134 {
4135         uint32_t ret;
4136
4137         ret = atomic_fetchadd_int(&number_of_tcp_connections_pacing, -1);
4138         shadow_num_connections = number_of_tcp_connections_pacing;
4139         KASSERT(ret != 0, ("tcp_paced_connection_exits -1 would cause wrap?"));
4140         if (ret == 0) {
4141                 if (tcp_pacing_limit != -1) {
4142                         printf("Warning all pacing is now disabled, count decrements invalidly!\n");
4143                         tcp_pacing_limit = 0;
4144                 } else if (tcp_pacing_warning == 0) {
4145                         printf("Warning pacing count is invalid, invalid decrement\n");
4146                         tcp_pacing_warning = 1;
4147                 }
4148         }
4149 }