xref: /freebsd/sys/netinet/tcp_subr.c (revision cfec995c87f39e59c80554b85625b4aaa8ddf8db)
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 
32 #include "opt_inet.h"
33 #include "opt_inet6.h"
34 #include "opt_ipsec.h"
35 #include "opt_kern_tls.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/arb.h>
40 #include <sys/callout.h>
41 #include <sys/eventhandler.h>
42 #ifdef TCP_HHOOK
43 #include <sys/hhook.h>
44 #endif
45 #include <sys/kernel.h>
46 #ifdef TCP_HHOOK
47 #include <sys/khelp.h>
48 #endif
49 #ifdef KERN_TLS
50 #include <sys/ktls.h>
51 #endif
52 #include <sys/qmath.h>
53 #include <sys/stats.h>
54 #include <sys/sysctl.h>
55 #include <sys/jail.h>
56 #include <sys/malloc.h>
57 #include <sys/refcount.h>
58 #include <sys/mbuf.h>
59 #include <sys/priv.h>
60 #include <sys/sdt.h>
61 #include <sys/socket.h>
62 #include <sys/socketvar.h>
63 #include <sys/protosw.h>
64 #include <sys/random.h>
65 
66 #include <vm/uma.h>
67 
68 #include <net/route.h>
69 #include <net/route/nhop.h>
70 #include <net/if.h>
71 #include <net/if_var.h>
72 #include <net/if_private.h>
73 #include <net/vnet.h>
74 
75 #include <netinet/in.h>
76 #include <netinet/in_fib.h>
77 #include <netinet/in_kdtrace.h>
78 #include <netinet/in_pcb.h>
79 #include <netinet/in_systm.h>
80 #include <netinet/in_var.h>
81 #include <netinet/ip.h>
82 #include <netinet/ip_icmp.h>
83 #include <netinet/ip_var.h>
84 #include <netinet/icmp_var.h>
85 #ifdef INET6
86 #include <netinet/icmp6.h>
87 #include <netinet/ip6.h>
88 #include <netinet6/in6_fib.h>
89 #include <netinet6/in6_pcb.h>
90 #include <netinet6/ip6_var.h>
91 #include <netinet6/scope6_var.h>
92 #include <netinet6/nd6.h>
93 #endif
94 
95 #include <netinet/tcp.h>
96 #ifdef INVARIANTS
97 #define TCPSTATES
98 #endif
99 #include <netinet/tcp_fsm.h>
100 #include <netinet/tcp_seq.h>
101 #include <netinet/tcp_timer.h>
102 #include <netinet/tcp_var.h>
103 #include <netinet/tcp_ecn.h>
104 #include <netinet/tcp_log_buf.h>
105 #include <netinet/tcp_syncache.h>
106 #include <netinet/tcp_hpts.h>
107 #include <netinet/tcp_lro.h>
108 #include <netinet/cc/cc.h>
109 #include <netinet/tcpip.h>
110 #include <netinet/tcp_fastopen.h>
111 #include <netinet/tcp_accounting.h>
112 #ifdef TCP_OFFLOAD
113 #include <netinet/tcp_offload.h>
114 #endif
115 #include <netinet/udp.h>
116 #include <netinet/udp_var.h>
117 #ifdef INET6
118 #include <netinet6/tcp6_var.h>
119 #endif
120 
121 #include <netipsec/ipsec_support.h>
122 
123 #include <machine/in_cksum.h>
124 #include <crypto/siphash/siphash.h>
125 
126 #include <security/mac/mac_framework.h>
127 
128 #ifdef INET6
129 static ip6proto_ctlinput_t tcp6_ctlinput;
130 static udp_tun_icmp_t tcp6_ctlinput_viaudp;
131 #endif
132 
133 VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS;
134 #ifdef INET6
135 VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS;
136 #endif
137 
138 VNET_DEFINE(uint32_t, tcp_ack_war_time_window) = 1000;
139 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, ack_war_timewindow,
140     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(tcp_ack_war_time_window), 0,
141    "Time interval in ms used to limit the number (ack_war_cnt) of challenge ACKs sent per TCP connection");
142 VNET_DEFINE(uint32_t, tcp_ack_war_cnt) = 5;
143 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, ack_war_cnt, CTLFLAG_VNET | CTLFLAG_RW,
144     &VNET_NAME(tcp_ack_war_cnt), 0,
145    "Maximum number of challenge ACKs sent per TCP connection during the time interval (ack_war_timewindow)");
146 
147 struct rwlock tcp_function_lock;
148 
149 static int
150 sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
151 {
152 	int error, new;
153 
154 	new = V_tcp_mssdflt;
155 	error = sysctl_handle_int(oidp, &new, 0, req);
156 	if (error == 0 && req->newptr) {
157 		if (new < TCP_MINMSS)
158 			error = EINVAL;
159 		else
160 			V_tcp_mssdflt = new;
161 	}
162 	return (error);
163 }
164 
165 SYSCTL_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
166     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
167     &VNET_NAME(tcp_mssdflt), 0, &sysctl_net_inet_tcp_mss_check, "I",
168     "Default TCP Maximum Segment Size");
169 
170 #ifdef INET6
171 static int
172 sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS)
173 {
174 	int error, new;
175 
176 	new = V_tcp_v6mssdflt;
177 	error = sysctl_handle_int(oidp, &new, 0, req);
178 	if (error == 0 && req->newptr) {
179 		if (new < TCP_MINMSS)
180 			error = EINVAL;
181 		else
182 			V_tcp_v6mssdflt = new;
183 	}
184 	return (error);
185 }
186 
187 SYSCTL_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
188     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
189     &VNET_NAME(tcp_v6mssdflt), 0, &sysctl_net_inet_tcp_mss_v6_check, "I",
190    "Default TCP Maximum Segment Size for IPv6");
191 #endif /* INET6 */
192 
193 /*
194  * Minimum MSS we accept and use. This prevents DoS attacks where
195  * we are forced to a ridiculous low MSS like 20 and send hundreds
196  * of packets instead of one. The effect scales with the available
197  * bandwidth and quickly saturates the CPU and network interface
198  * with packet generation and sending. Set to zero to disable MINMSS
199  * checking. This setting prevents us from sending too small packets.
200  */
201 VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS;
202 SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_VNET | CTLFLAG_RW,
203      &VNET_NAME(tcp_minmss), 0,
204     "Minimum TCP Maximum Segment Size");
205 
206 VNET_DEFINE(int, tcp_do_rfc1323) = 1;
207 SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_VNET | CTLFLAG_RW,
208     &VNET_NAME(tcp_do_rfc1323), 0,
209     "Enable rfc1323 (high performance TCP) extensions");
210 
211 /*
212  * As of June 2021, several TCP stacks violate RFC 7323 from September 2014.
213  * Some stacks negotiate TS, but never send them after connection setup. Some
214  * stacks negotiate TS, but don't send them when sending keep-alive segments.
215  * These include modern widely deployed TCP stacks.
216  * Therefore tolerating violations for now...
217  */
218 VNET_DEFINE(int, tcp_tolerate_missing_ts) = 1;
219 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tolerate_missing_ts, CTLFLAG_VNET | CTLFLAG_RW,
220     &VNET_NAME(tcp_tolerate_missing_ts), 0,
221     "Tolerate missing TCP timestamps");
222 
223 VNET_DEFINE(int, tcp_ts_offset_per_conn) = 1;
224 SYSCTL_INT(_net_inet_tcp, OID_AUTO, ts_offset_per_conn, CTLFLAG_VNET | CTLFLAG_RW,
225     &VNET_NAME(tcp_ts_offset_per_conn), 0,
226     "Initialize TCP timestamps per connection instead of per host pair");
227 
228 /* How many connections are pacing */
229 static volatile uint32_t number_of_tcp_connections_pacing = 0;
230 static uint32_t shadow_num_connections = 0;
231 static counter_u64_t tcp_pacing_failures;
232 static counter_u64_t tcp_dgp_failures;
233 static uint32_t shadow_tcp_pacing_dgp = 0;
234 static volatile uint32_t number_of_dgp_connections = 0;
235 
236 static int tcp_pacing_limit = 10000;
237 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pacing_limit, CTLFLAG_RW,
238     &tcp_pacing_limit, 1000,
239     "If the TCP stack does pacing, is there a limit (-1 = no, 0 = no pacing N = number of connections)");
240 
241 static int tcp_dgp_limit = -1;
242 SYSCTL_INT(_net_inet_tcp, OID_AUTO, dgp_limit, CTLFLAG_RW,
243     &tcp_dgp_limit, -1,
244     "If the TCP stack does DGP, is there a limit (-1 = no, 0 = no dgp N = number of connections)");
245 
246 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, pacing_count, CTLFLAG_RD,
247     &shadow_num_connections, 0, "Number of TCP connections being paced");
248 
249 SYSCTL_COUNTER_U64(_net_inet_tcp, OID_AUTO, pacing_failures, CTLFLAG_RD,
250     &tcp_pacing_failures, "Number of times we failed to enable pacing to avoid exceeding the limit");
251 
252 SYSCTL_COUNTER_U64(_net_inet_tcp, OID_AUTO, dgp_failures, CTLFLAG_RD,
253     &tcp_dgp_failures, "Number of times we failed to enable dgp to avoid exceeding the limit");
254 
255 static int	tcp_log_debug = 0;
256 SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW,
257     &tcp_log_debug, 0, "Log errors caused by incoming TCP segments");
258 
259 /*
260  * Target size of TCP PCB hash tables. Must be a power of two.
261  *
262  * Note that this can be overridden by the kernel environment
263  * variable net.inet.tcp.tcbhashsize
264  */
265 #ifndef TCBHASHSIZE
266 #define TCBHASHSIZE	0
267 #endif
268 static int	tcp_tcbhashsize = TCBHASHSIZE;
269 SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN,
270     &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
271 
272 static int	do_tcpdrain = 1;
273 SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
274     "Enable tcp_drain routine for extra help when low on mbufs");
275 
276 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_VNET | CTLFLAG_RD,
277     &VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
278 
279 VNET_DEFINE_STATIC(int, icmp_may_rst) = 1;
280 #define	V_icmp_may_rst			VNET(icmp_may_rst)
281 SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_VNET | CTLFLAG_RW,
282     &VNET_NAME(icmp_may_rst), 0,
283     "Certain ICMP unreachable messages may abort connections in SYN_SENT");
284 
285 VNET_DEFINE_STATIC(int, tcp_isn_reseed_interval) = 0;
286 #define	V_tcp_isn_reseed_interval	VNET(tcp_isn_reseed_interval)
287 SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_VNET | CTLFLAG_RW,
288     &VNET_NAME(tcp_isn_reseed_interval), 0,
289     "Seconds between reseeding of ISN secret");
290 
291 static int	tcp_soreceive_stream;
292 SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
293     &tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
294 
295 VNET_DEFINE(uma_zone_t, sack_hole_zone);
296 #define	V_sack_hole_zone		VNET(sack_hole_zone)
297 VNET_DEFINE(uint32_t, tcp_map_entries_limit) = 0;	/* unlimited */
298 static int
299 sysctl_net_inet_tcp_map_limit_check(SYSCTL_HANDLER_ARGS)
300 {
301 	int error;
302 	uint32_t new;
303 
304 	new = V_tcp_map_entries_limit;
305 	error = sysctl_handle_int(oidp, &new, 0, req);
306 	if (error == 0 && req->newptr) {
307 		/* only allow "0" and value > minimum */
308 		if (new > 0 && new < TCP_MIN_MAP_ENTRIES_LIMIT)
309 			error = EINVAL;
310 		else
311 			V_tcp_map_entries_limit = new;
312 	}
313 	return (error);
314 }
315 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, map_limit,
316     CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
317     &VNET_NAME(tcp_map_entries_limit), 0,
318     &sysctl_net_inet_tcp_map_limit_check, "IU",
319     "Total sendmap entries limit");
320 
321 VNET_DEFINE(uint32_t, tcp_map_split_limit) = 0;	/* unlimited */
322 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, split_limit, CTLFLAG_VNET | CTLFLAG_RW,
323      &VNET_NAME(tcp_map_split_limit), 0,
324     "Total sendmap split entries limit");
325 
326 #ifdef TCP_HHOOK
327 VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]);
328 #endif
329 
330 #define TS_OFFSET_SECRET_LENGTH SIPHASH_KEY_LENGTH
331 VNET_DEFINE_STATIC(u_char, ts_offset_secret[TS_OFFSET_SECRET_LENGTH]);
332 #define	V_ts_offset_secret	VNET(ts_offset_secret)
333 
334 static int	tcp_default_fb_init(struct tcpcb *tp, void **ptr);
335 static void	tcp_default_fb_fini(struct tcpcb *tp, int tcb_is_purged);
336 static int	tcp_default_handoff_ok(struct tcpcb *tp);
337 static struct inpcb *tcp_notify(struct inpcb *, int);
338 static struct inpcb *tcp_mtudisc_notify(struct inpcb *, int);
339 static struct inpcb *tcp_mtudisc(struct inpcb *, int);
340 static struct inpcb *tcp_drop_syn_sent(struct inpcb *, int);
341 static char *	tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th,
342 		    const void *ip4hdr, const void *ip6hdr);
343 static void	tcp_default_switch_failed(struct tcpcb *tp);
344 
345 #ifdef INET
346 static ipproto_ctlinput_t	tcp_ctlinput;
347 static udp_tun_icmp_t		tcp_ctlinput_viaudp;
348 #endif
349 
350 static struct tcp_function_block tcp_def_funcblk = {
351 	.tfb_tcp_block_name = "freebsd",
352 	.tfb_tcp_output = tcp_default_output,
353 	.tfb_tcp_do_segment = tcp_do_segment,
354 	.tfb_tcp_ctloutput = tcp_default_ctloutput,
355 	.tfb_tcp_handoff_ok = tcp_default_handoff_ok,
356 	.tfb_tcp_fb_init = tcp_default_fb_init,
357 	.tfb_tcp_fb_fini = tcp_default_fb_fini,
358 	.tfb_switch_failed = tcp_default_switch_failed,
359 	.tfb_flags = TCP_FUNC_DEFAULT_OK,
360 };
361 
362 static int tcp_fb_cnt = 0;
363 struct tcp_funchead t_functions;
364 VNET_DEFINE_STATIC(struct tcp_function_block *, tcp_func_set_ptr) = &tcp_def_funcblk;
365 #define	V_tcp_func_set_ptr VNET(tcp_func_set_ptr)
366 
367 void
368 tcp_record_dsack(struct tcpcb *tp, tcp_seq start, tcp_seq end, int tlp)
369 {
370 	TCPSTAT_INC(tcps_dsack_count);
371 	tp->t_dsack_pack++;
372 	if (tlp == 0) {
373 		if (SEQ_GT(end, start)) {
374 			tp->t_dsack_bytes += (end - start);
375 			TCPSTAT_ADD(tcps_dsack_bytes, (end - start));
376 		} else {
377 			tp->t_dsack_tlp_bytes += (start - end);
378 			TCPSTAT_ADD(tcps_dsack_bytes, (start - end));
379 		}
380 	} else {
381 		if (SEQ_GT(end, start)) {
382 			tp->t_dsack_bytes += (end - start);
383 			TCPSTAT_ADD(tcps_dsack_tlp_bytes, (end - start));
384 		} else {
385 			tp->t_dsack_tlp_bytes += (start - end);
386 			TCPSTAT_ADD(tcps_dsack_tlp_bytes, (start - end));
387 		}
388 	}
389 }
390 
391 static struct tcp_function_block *
392 find_tcp_functions_locked(struct tcp_function_set *fs)
393 {
394 	struct tcp_function *f;
395 	struct tcp_function_block *blk = NULL;
396 
397 	rw_assert(&tcp_function_lock, RA_LOCKED);
398 	TAILQ_FOREACH(f, &t_functions, tf_next) {
399 		if (strcmp(f->tf_name, fs->function_set_name) == 0) {
400 			blk = f->tf_fb;
401 			break;
402 		}
403 	}
404 	return (blk);
405 }
406 
407 static struct tcp_function_block *
408 find_tcp_fb_locked(struct tcp_function_block *blk, struct tcp_function **s)
409 {
410 	struct tcp_function_block *rblk = NULL;
411 	struct tcp_function *f;
412 
413 	rw_assert(&tcp_function_lock, RA_LOCKED);
414 	TAILQ_FOREACH(f, &t_functions, tf_next) {
415 		if (f->tf_fb == blk) {
416 			rblk = blk;
417 			if (s) {
418 				*s = f;
419 			}
420 			break;
421 		}
422 	}
423 	return (rblk);
424 }
425 
426 struct tcp_function_block *
427 find_and_ref_tcp_functions(struct tcp_function_set *fs)
428 {
429 	struct tcp_function_block *blk;
430 
431 	rw_rlock(&tcp_function_lock);
432 	blk = find_tcp_functions_locked(fs);
433 	if (blk)
434 		refcount_acquire(&blk->tfb_refcnt);
435 	rw_runlock(&tcp_function_lock);
436 	return (blk);
437 }
438 
439 struct tcp_function_block *
440 find_and_ref_tcp_fb(struct tcp_function_block *blk)
441 {
442 	struct tcp_function_block *rblk;
443 
444 	rw_rlock(&tcp_function_lock);
445 	rblk = find_tcp_fb_locked(blk, NULL);
446 	if (rblk)
447 		refcount_acquire(&rblk->tfb_refcnt);
448 	rw_runlock(&tcp_function_lock);
449 	return (rblk);
450 }
451 
452 /* Find a matching alias for the given tcp_function_block. */
453 int
454 find_tcp_function_alias(struct tcp_function_block *blk,
455     struct tcp_function_set *fs)
456 {
457 	struct tcp_function *f;
458 	int found;
459 
460 	found = 0;
461 	rw_rlock(&tcp_function_lock);
462 	TAILQ_FOREACH(f, &t_functions, tf_next) {
463 		if ((f->tf_fb == blk) &&
464 		    (strncmp(f->tf_name, blk->tfb_tcp_block_name,
465 		        TCP_FUNCTION_NAME_LEN_MAX) != 0)) {
466 			/* Matching function block with different name. */
467 			strncpy(fs->function_set_name, f->tf_name,
468 			    TCP_FUNCTION_NAME_LEN_MAX);
469 			found = 1;
470 			break;
471 		}
472 	}
473 	/* Null terminate the string appropriately. */
474 	if (found) {
475 		fs->function_set_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
476 	} else {
477 		fs->function_set_name[0] = '\0';
478 	}
479 	rw_runlock(&tcp_function_lock);
480 	return (found);
481 }
482 
483 static struct tcp_function_block *
484 find_and_ref_tcp_default_fb(void)
485 {
486 	struct tcp_function_block *rblk;
487 
488 	rw_rlock(&tcp_function_lock);
489 	rblk = V_tcp_func_set_ptr;
490 	refcount_acquire(&rblk->tfb_refcnt);
491 	rw_runlock(&tcp_function_lock);
492 	return (rblk);
493 }
494 
495 void
496 tcp_switch_back_to_default(struct tcpcb *tp)
497 {
498 	struct tcp_function_block *tfb;
499 	void *ptr = NULL;
500 
501 	KASSERT(tp->t_fb != &tcp_def_funcblk,
502 	    ("%s: called by the built-in default stack", __func__));
503 
504 	if (tp->t_fb->tfb_tcp_timer_stop_all != NULL)
505 		tp->t_fb->tfb_tcp_timer_stop_all(tp);
506 
507 	/*
508 	 * Now, we'll find a new function block to use.
509 	 * Start by trying the current user-selected
510 	 * default, unless this stack is the user-selected
511 	 * default.
512 	 */
513 	tfb = find_and_ref_tcp_default_fb();
514 	if (tfb == tp->t_fb) {
515 		refcount_release(&tfb->tfb_refcnt);
516 		tfb = NULL;
517 	}
518 	/* Does the stack accept this connection? */
519 	if (tfb != NULL && (*tfb->tfb_tcp_handoff_ok)(tp)) {
520 		refcount_release(&tfb->tfb_refcnt);
521 		tfb = NULL;
522 	}
523 	/* Try to use that stack. */
524 	if (tfb != NULL) {
525 		/* Initialize the new stack. If it succeeds, we are done. */
526 		if (tfb->tfb_tcp_fb_init == NULL ||
527 		    (*tfb->tfb_tcp_fb_init)(tp, &ptr) == 0) {
528 			/* Release the old stack */
529 			if (tp->t_fb->tfb_tcp_fb_fini != NULL)
530 				(*tp->t_fb->tfb_tcp_fb_fini)(tp, 0);
531 			refcount_release(&tp->t_fb->tfb_refcnt);
532 			/* Now set in all the pointers */
533 			tp->t_fb = tfb;
534 			tp->t_fb_ptr = ptr;
535 			return;
536 		}
537 		/*
538 		 * Initialization failed. Release the reference count on
539 		 * the looked up default stack.
540 		 */
541 		refcount_release(&tfb->tfb_refcnt);
542 	}
543 
544 	/*
545 	 * If that wasn't feasible, use the built-in default
546 	 * stack which is not allowed to reject anyone.
547 	 */
548 	tfb = find_and_ref_tcp_fb(&tcp_def_funcblk);
549 	if (tfb == NULL) {
550 		/* there always should be a default */
551 		panic("Can't refer to tcp_def_funcblk");
552 	}
553 	if ((*tfb->tfb_tcp_handoff_ok)(tp)) {
554 		/* The default stack cannot say no */
555 		panic("Default stack rejects a new session?");
556 	}
557 	if (tfb->tfb_tcp_fb_init != NULL &&
558 	    (*tfb->tfb_tcp_fb_init)(tp, &ptr)) {
559 		/* The default stack cannot fail */
560 		panic("Default stack initialization failed");
561 	}
562 	/* Now release the old stack */
563 	if (tp->t_fb->tfb_tcp_fb_fini != NULL)
564 		(*tp->t_fb->tfb_tcp_fb_fini)(tp, 0);
565 	refcount_release(&tp->t_fb->tfb_refcnt);
566 	/* And set in the pointers to the new */
567 	tp->t_fb = tfb;
568 	tp->t_fb_ptr = ptr;
569 }
570 
571 static bool
572 tcp_recv_udp_tunneled_packet(struct mbuf *m, int off, struct inpcb *inp,
573     const struct sockaddr *sa, void *ctx)
574 {
575 	struct ip *iph;
576 #ifdef INET6
577 	struct ip6_hdr *ip6;
578 #endif
579 	struct udphdr *uh;
580 	struct tcphdr *th;
581 	int len, thlen;
582 	uint16_t port;
583 
584 	TCPSTAT_INC(tcps_tunneled_pkts);
585 	if ((m->m_flags & M_PKTHDR) == 0) {
586 		/* Can't handle one that is not a pkt hdr */
587 		TCPSTAT_INC(tcps_tunneled_errs);
588 		m_freem(m);
589 		return (true);
590 	}
591 	thlen = sizeof(struct tcphdr);
592 	if (m->m_len < off + sizeof(struct udphdr) + thlen &&
593 	    (m =  m_pullup(m, off + sizeof(struct udphdr) + thlen)) == NULL) {
594 		TCPSTAT_INC(tcps_tunneled_errs);
595 		return (true);
596 	}
597 	iph = mtod(m, struct ip *);
598 	uh = (struct udphdr *)((caddr_t)iph + off);
599 	th = (struct tcphdr *)(uh + 1);
600 	thlen = th->th_off << 2;
601 	if (m->m_len < off + sizeof(struct udphdr) + thlen) {
602 		m =  m_pullup(m, off + sizeof(struct udphdr) + thlen);
603 		if (m == NULL) {
604 			TCPSTAT_INC(tcps_tunneled_errs);
605 			return (true);
606 		} else {
607 			iph = mtod(m, struct ip *);
608 			uh = (struct udphdr *)((caddr_t)iph + off);
609 			th = (struct tcphdr *)(uh + 1);
610 		}
611 	}
612 	m->m_pkthdr.tcp_tun_port = port = uh->uh_sport;
613 	bcopy(th, uh, m->m_len - off - sizeof(struct udphdr));
614 	m->m_len -= sizeof(struct udphdr);
615 	m->m_pkthdr.len -= sizeof(struct udphdr);
616 	/*
617 	 * We use the same algorithm for
618 	 * both UDP and TCP for c-sum. So
619 	 * the code in tcp_input will skip
620 	 * the checksum. So we do nothing
621 	 * with the flag (m->m_pkthdr.csum_flags).
622 	 */
623 	switch (iph->ip_v) {
624 #ifdef INET
625 	case IPVERSION:
626 		len = ntohs(iph->ip_len) - sizeof(struct udphdr);
627 		if (__predict_false(len != m->m_pkthdr.len)) {
628 			TCPSTAT_INC(tcps_tunneled_errs);
629 			m_freem(m);
630 			return (true);
631 		} else {
632 			iph->ip_len = htons(len);
633 			tcp_input_with_port(&m, &off, IPPROTO_TCP, port);
634 		}
635 		break;
636 #endif
637 #ifdef INET6
638 	case IPV6_VERSION >> 4:
639 		ip6 = mtod(m, struct ip6_hdr *);
640 		len = ntohs(ip6->ip6_plen) - sizeof(struct udphdr);
641 		if (__predict_false(len + sizeof(struct ip6_hdr) !=
642 		    m->m_pkthdr.len)) {
643 			TCPSTAT_INC(tcps_tunneled_errs);
644 			m_freem(m);
645 			return (true);
646 		} else {
647 			ip6->ip6_plen = htons(len);
648 			tcp6_input_with_port(&m, &off, IPPROTO_TCP, port);
649 		}
650 		break;
651 #endif
652 	default:
653 		m_freem(m);
654 		break;
655 	}
656 	return (true);
657 }
658 
659 static int
660 sysctl_net_inet_default_tcp_functions(SYSCTL_HANDLER_ARGS)
661 {
662 	struct tcp_function_set fs;
663 	struct tcp_function_block *blk;
664 	int error;
665 
666 	memset(&fs, 0, sizeof(struct tcp_function_set));
667 	rw_rlock(&tcp_function_lock);
668 	blk = find_tcp_fb_locked(V_tcp_func_set_ptr, NULL);
669 	if (blk != NULL) {
670 		/* Found him */
671 		strcpy(fs.function_set_name, blk->tfb_tcp_block_name);
672 		fs.pcbcnt = blk->tfb_refcnt;
673 	}
674 	rw_runlock(&tcp_function_lock);
675 	error = sysctl_handle_string(oidp, fs.function_set_name,
676 				     sizeof(fs.function_set_name), req);
677 
678 	/* Check for error or no change */
679 	if (error != 0 || req->newptr == NULL)
680 		return (error);
681 
682 	rw_wlock(&tcp_function_lock);
683 	blk = find_tcp_functions_locked(&fs);
684 	if ((blk == NULL) ||
685 	    (blk->tfb_flags & TCP_FUNC_BEING_REMOVED)) {
686 		error = ENOENT;
687 		goto done;
688 	}
689 	if ((blk->tfb_flags & TCP_FUNC_DEFAULT_OK) == 0) {
690 		error = EINVAL;
691 		goto done;
692 	}
693 	V_tcp_func_set_ptr = blk;
694 done:
695 	rw_wunlock(&tcp_function_lock);
696 	return (error);
697 }
698 
699 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_default,
700     CTLFLAG_VNET | CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
701     NULL, 0, sysctl_net_inet_default_tcp_functions, "A",
702     "Set/get the default TCP functions");
703 
704 static int
705 sysctl_net_inet_list_available(SYSCTL_HANDLER_ARGS)
706 {
707 	int error, cnt, linesz;
708 	struct tcp_function *f;
709 	char *buffer, *cp;
710 	size_t bufsz, outsz;
711 	bool alias;
712 
713 	cnt = 0;
714 	rw_rlock(&tcp_function_lock);
715 	TAILQ_FOREACH(f, &t_functions, tf_next) {
716 		cnt++;
717 	}
718 	rw_runlock(&tcp_function_lock);
719 
720 	bufsz = (cnt+2) * ((TCP_FUNCTION_NAME_LEN_MAX * 2) + 13) + 1;
721 	buffer = malloc(bufsz, M_TEMP, M_WAITOK);
722 
723 	error = 0;
724 	cp = buffer;
725 
726 	linesz = snprintf(cp, bufsz, "\n%-32s%c %-32s %s\n", "Stack", 'D',
727 	    "Alias", "PCB count");
728 	cp += linesz;
729 	bufsz -= linesz;
730 	outsz = linesz;
731 
732 	rw_rlock(&tcp_function_lock);
733 	TAILQ_FOREACH(f, &t_functions, tf_next) {
734 		alias = (f->tf_name != f->tf_fb->tfb_tcp_block_name);
735 		linesz = snprintf(cp, bufsz, "%-32s%c %-32s %u\n",
736 		    f->tf_fb->tfb_tcp_block_name,
737 		    (f->tf_fb == V_tcp_func_set_ptr) ? '*' : ' ',
738 		    alias ? f->tf_name : "-",
739 		    f->tf_fb->tfb_refcnt);
740 		if (linesz >= bufsz) {
741 			error = EOVERFLOW;
742 			break;
743 		}
744 		cp += linesz;
745 		bufsz -= linesz;
746 		outsz += linesz;
747 	}
748 	rw_runlock(&tcp_function_lock);
749 	if (error == 0)
750 		error = sysctl_handle_string(oidp, buffer, outsz + 1, req);
751 	free(buffer, M_TEMP);
752 	return (error);
753 }
754 
755 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_available,
756     CTLFLAG_VNET | CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT,
757     NULL, 0, sysctl_net_inet_list_available, "A",
758     "list available TCP Function sets");
759 
760 VNET_DEFINE(int, tcp_udp_tunneling_port) = TCP_TUNNELING_PORT_DEFAULT;
761 
762 #ifdef INET
763 VNET_DEFINE(struct socket *, udp4_tun_socket) = NULL;
764 #define	V_udp4_tun_socket	VNET(udp4_tun_socket)
765 #endif
766 #ifdef INET6
767 VNET_DEFINE(struct socket *, udp6_tun_socket) = NULL;
768 #define	V_udp6_tun_socket	VNET(udp6_tun_socket)
769 #endif
770 
771 static struct sx tcpoudp_lock;
772 
773 static void
774 tcp_over_udp_stop(void)
775 {
776 
777 	sx_assert(&tcpoudp_lock, SA_XLOCKED);
778 
779 #ifdef INET
780 	if (V_udp4_tun_socket != NULL) {
781 		soclose(V_udp4_tun_socket);
782 		V_udp4_tun_socket = NULL;
783 	}
784 #endif
785 #ifdef INET6
786 	if (V_udp6_tun_socket != NULL) {
787 		soclose(V_udp6_tun_socket);
788 		V_udp6_tun_socket = NULL;
789 	}
790 #endif
791 }
792 
793 static int
794 tcp_over_udp_start(void)
795 {
796 	uint16_t port;
797 	int ret;
798 #ifdef INET
799 	struct sockaddr_in sin;
800 #endif
801 #ifdef INET6
802 	struct sockaddr_in6 sin6;
803 #endif
804 
805 	sx_assert(&tcpoudp_lock, SA_XLOCKED);
806 
807 	port = V_tcp_udp_tunneling_port;
808 	if (ntohs(port) == 0) {
809 		/* Must have a port set */
810 		return (EINVAL);
811 	}
812 #ifdef INET
813 	if (V_udp4_tun_socket != NULL) {
814 		/* Already running -- must stop first */
815 		return (EALREADY);
816 	}
817 #endif
818 #ifdef INET6
819 	if (V_udp6_tun_socket != NULL) {
820 		/* Already running -- must stop first */
821 		return (EALREADY);
822 	}
823 #endif
824 #ifdef INET
825 	if ((ret = socreate(PF_INET, &V_udp4_tun_socket,
826 	    SOCK_DGRAM, IPPROTO_UDP,
827 	    curthread->td_ucred, curthread))) {
828 		tcp_over_udp_stop();
829 		return (ret);
830 	}
831 	/* Call the special UDP hook. */
832 	if ((ret = udp_set_kernel_tunneling(V_udp4_tun_socket,
833 	    tcp_recv_udp_tunneled_packet,
834 	    tcp_ctlinput_viaudp,
835 	    NULL))) {
836 		tcp_over_udp_stop();
837 		return (ret);
838 	}
839 	/* Ok, we have a socket, bind it to the port. */
840 	memset(&sin, 0, sizeof(struct sockaddr_in));
841 	sin.sin_len = sizeof(struct sockaddr_in);
842 	sin.sin_family = AF_INET;
843 	sin.sin_port = htons(port);
844 	if ((ret = sobind(V_udp4_tun_socket,
845 	    (struct sockaddr *)&sin, curthread))) {
846 		tcp_over_udp_stop();
847 		return (ret);
848 	}
849 #endif
850 #ifdef INET6
851 	if ((ret = socreate(PF_INET6, &V_udp6_tun_socket,
852 	    SOCK_DGRAM, IPPROTO_UDP,
853 	    curthread->td_ucred, curthread))) {
854 		tcp_over_udp_stop();
855 		return (ret);
856 	}
857 	/* Call the special UDP hook. */
858 	if ((ret = udp_set_kernel_tunneling(V_udp6_tun_socket,
859 	    tcp_recv_udp_tunneled_packet,
860 	    tcp6_ctlinput_viaudp,
861 	    NULL))) {
862 		tcp_over_udp_stop();
863 		return (ret);
864 	}
865 	/* Ok, we have a socket, bind it to the port. */
866 	memset(&sin6, 0, sizeof(struct sockaddr_in6));
867 	sin6.sin6_len = sizeof(struct sockaddr_in6);
868 	sin6.sin6_family = AF_INET6;
869 	sin6.sin6_port = htons(port);
870 	if ((ret = sobind(V_udp6_tun_socket,
871 	    (struct sockaddr *)&sin6, curthread))) {
872 		tcp_over_udp_stop();
873 		return (ret);
874 	}
875 #endif
876 	return (0);
877 }
878 
879 static int
880 sysctl_net_inet_tcp_udp_tunneling_port_check(SYSCTL_HANDLER_ARGS)
881 {
882 	int error;
883 	uint32_t old, new;
884 
885 	old = V_tcp_udp_tunneling_port;
886 	new = old;
887 	error = sysctl_handle_int(oidp, &new, 0, req);
888 	if ((error == 0) &&
889 	    (req->newptr != NULL)) {
890 		if ((new < TCP_TUNNELING_PORT_MIN) ||
891 		    (new > TCP_TUNNELING_PORT_MAX)) {
892 			error = EINVAL;
893 		} else {
894 			sx_xlock(&tcpoudp_lock);
895 			V_tcp_udp_tunneling_port = new;
896 			if (old != 0) {
897 				tcp_over_udp_stop();
898 			}
899 			if (new != 0) {
900 				error = tcp_over_udp_start();
901 				if (error != 0) {
902 					V_tcp_udp_tunneling_port = 0;
903 				}
904 			}
905 			sx_xunlock(&tcpoudp_lock);
906 		}
907 	}
908 	return (error);
909 }
910 
911 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, udp_tunneling_port,
912     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
913     &VNET_NAME(tcp_udp_tunneling_port),
914     0, &sysctl_net_inet_tcp_udp_tunneling_port_check, "IU",
915     "Tunneling port for tcp over udp");
916 
917 VNET_DEFINE(int, tcp_udp_tunneling_overhead) = TCP_TUNNELING_OVERHEAD_DEFAULT;
918 
919 static int
920 sysctl_net_inet_tcp_udp_tunneling_overhead_check(SYSCTL_HANDLER_ARGS)
921 {
922 	int error, new;
923 
924 	new = V_tcp_udp_tunneling_overhead;
925 	error = sysctl_handle_int(oidp, &new, 0, req);
926 	if (error == 0 && req->newptr) {
927 		if ((new < TCP_TUNNELING_OVERHEAD_MIN) ||
928 		    (new > TCP_TUNNELING_OVERHEAD_MAX))
929 			error = EINVAL;
930 		else
931 			V_tcp_udp_tunneling_overhead = new;
932 	}
933 	return (error);
934 }
935 
936 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, udp_tunneling_overhead,
937     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
938     &VNET_NAME(tcp_udp_tunneling_overhead),
939     0, &sysctl_net_inet_tcp_udp_tunneling_overhead_check, "IU",
940     "MSS reduction when using tcp over udp");
941 
942 /*
943  * Exports one (struct tcp_function_info) for each alias/name.
944  */
945 static int
946 sysctl_net_inet_list_func_info(SYSCTL_HANDLER_ARGS)
947 {
948 	int cnt, error;
949 	struct tcp_function *f;
950 	struct tcp_function_info tfi;
951 
952 	/*
953 	 * We don't allow writes.
954 	 */
955 	if (req->newptr != NULL)
956 		return (EINVAL);
957 
958 	/*
959 	 * Wire the old buffer so we can directly copy the functions to
960 	 * user space without dropping the lock.
961 	 */
962 	if (req->oldptr != NULL) {
963 		error = sysctl_wire_old_buffer(req, 0);
964 		if (error)
965 			return (error);
966 	}
967 
968 	/*
969 	 * Walk the list and copy out matching entries. If INVARIANTS
970 	 * is compiled in, also walk the list to verify the length of
971 	 * the list matches what we have recorded.
972 	 */
973 	rw_rlock(&tcp_function_lock);
974 
975 	cnt = 0;
976 #ifndef INVARIANTS
977 	if (req->oldptr == NULL) {
978 		cnt = tcp_fb_cnt;
979 		goto skip_loop;
980 	}
981 #endif
982 	TAILQ_FOREACH(f, &t_functions, tf_next) {
983 #ifdef INVARIANTS
984 		cnt++;
985 #endif
986 		if (req->oldptr != NULL) {
987 			bzero(&tfi, sizeof(tfi));
988 			tfi.tfi_refcnt = f->tf_fb->tfb_refcnt;
989 			tfi.tfi_id = f->tf_fb->tfb_id;
990 			(void)strlcpy(tfi.tfi_alias, f->tf_name,
991 			    sizeof(tfi.tfi_alias));
992 			(void)strlcpy(tfi.tfi_name,
993 			    f->tf_fb->tfb_tcp_block_name, sizeof(tfi.tfi_name));
994 			error = SYSCTL_OUT(req, &tfi, sizeof(tfi));
995 			/*
996 			 * Don't stop on error, as that is the
997 			 * mechanism we use to accumulate length
998 			 * information if the buffer was too short.
999 			 */
1000 		}
1001 	}
1002 	KASSERT(cnt == tcp_fb_cnt,
1003 	    ("%s: cnt (%d) != tcp_fb_cnt (%d)", __func__, cnt, tcp_fb_cnt));
1004 #ifndef INVARIANTS
1005 skip_loop:
1006 #endif
1007 	rw_runlock(&tcp_function_lock);
1008 	if (req->oldptr == NULL)
1009 		error = SYSCTL_OUT(req, NULL,
1010 		    (cnt + 1) * sizeof(struct tcp_function_info));
1011 
1012 	return (error);
1013 }
1014 
1015 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, function_info,
1016 	    CTLTYPE_OPAQUE | CTLFLAG_SKIP | CTLFLAG_RD | CTLFLAG_MPSAFE,
1017 	    NULL, 0, sysctl_net_inet_list_func_info, "S,tcp_function_info",
1018 	    "List TCP function block name-to-ID mappings");
1019 
1020 /*
1021  * tfb_tcp_handoff_ok() function for the default stack.
1022  * Note that we'll basically try to take all comers.
1023  */
1024 static int
1025 tcp_default_handoff_ok(struct tcpcb *tp)
1026 {
1027 
1028 	return (0);
1029 }
1030 
1031 /*
1032  * tfb_tcp_fb_init() function for the default stack.
1033  *
1034  * This handles making sure we have appropriate timers set if you are
1035  * transitioning a socket that has some amount of setup done.
1036  *
1037  * The init() fuction from the default can *never* return non-zero i.e.
1038  * it is required to always succeed since it is the stack of last resort!
1039  */
1040 static int
1041 tcp_default_fb_init(struct tcpcb *tp, void **ptr)
1042 {
1043 	struct socket *so = tptosocket(tp);
1044 	int rexmt;
1045 
1046 	INP_WLOCK_ASSERT(tptoinpcb(tp));
1047 	/* We don't use the pointer */
1048 	*ptr = NULL;
1049 
1050 	/* Make sure we get no interesting mbuf queuing behavior */
1051 	/* All mbuf queue/ack compress flags should be off */
1052 	tcp_lro_features_off(tp);
1053 
1054 	/* Cancel the GP measurement in progress */
1055 	tp->t_flags &= ~TF_GPUTINPROG;
1056 	/* Validate the timers are not in usec, if they are convert */
1057 	tcp_change_time_units(tp, TCP_TMR_GRANULARITY_TICKS);
1058 	if ((tp->t_state == TCPS_SYN_SENT) ||
1059 	    (tp->t_state == TCPS_SYN_RECEIVED))
1060 		rexmt = tcp_rexmit_initial * tcp_backoff[tp->t_rxtshift];
1061 	else
1062 		rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
1063 	if (tp->t_rxtshift == 0)
1064 		tp->t_rxtcur = rexmt;
1065 	else
1066 		TCPT_RANGESET(tp->t_rxtcur, rexmt, tp->t_rttmin,
1067 		    tcp_rexmit_max);
1068 
1069 	/*
1070 	 * Nothing to do for ESTABLISHED or LISTEN states. And, we don't
1071 	 * know what to do for unexpected states (which includes TIME_WAIT).
1072 	 */
1073 	if (tp->t_state <= TCPS_LISTEN || tp->t_state >= TCPS_TIME_WAIT)
1074 		return (0);
1075 
1076 	/*
1077 	 * Make sure some kind of transmission timer is set if there is
1078 	 * outstanding data.
1079 	 */
1080 	if ((!TCPS_HAVEESTABLISHED(tp->t_state) || sbavail(&so->so_snd) ||
1081 	    tp->snd_una != tp->snd_max) && !(tcp_timer_active(tp, TT_REXMT) ||
1082 	    tcp_timer_active(tp, TT_PERSIST))) {
1083 		/*
1084 		 * If the session has established and it looks like it should
1085 		 * be in the persist state, set the persist timer. Otherwise,
1086 		 * set the retransmit timer.
1087 		 */
1088 		if (TCPS_HAVEESTABLISHED(tp->t_state) && tp->snd_wnd == 0 &&
1089 		    (int32_t)(tp->snd_nxt - tp->snd_una) <
1090 		    (int32_t)sbavail(&so->so_snd))
1091 			tcp_setpersist(tp);
1092 		else
1093 			tcp_timer_activate(tp, TT_REXMT, TP_RXTCUR(tp));
1094 	}
1095 
1096 	/* All non-embryonic sessions get a keepalive timer. */
1097 	if (!tcp_timer_active(tp, TT_KEEP))
1098 		tcp_timer_activate(tp, TT_KEEP,
1099 		    TCPS_HAVEESTABLISHED(tp->t_state) ? TP_KEEPIDLE(tp) :
1100 		    TP_KEEPINIT(tp));
1101 
1102 	/*
1103 	 * Make sure critical variables are initialized
1104 	 * if transitioning while in Recovery.
1105 	 */
1106 	if IN_FASTRECOVERY(tp->t_flags) {
1107 		if (tp->sackhint.recover_fs == 0)
1108 			tp->sackhint.recover_fs = max(1,
1109 			    tp->snd_nxt - tp->snd_una);
1110 	}
1111 
1112 	return (0);
1113 }
1114 
1115 /*
1116  * tfb_tcp_fb_fini() function for the default stack.
1117  *
1118  * This changes state as necessary (or prudent) to prepare for another stack
1119  * to assume responsibility for the connection.
1120  */
1121 static void
1122 tcp_default_fb_fini(struct tcpcb *tp, int tcb_is_purged)
1123 {
1124 
1125 	INP_WLOCK_ASSERT(tptoinpcb(tp));
1126 
1127 #ifdef TCP_BLACKBOX
1128 	tcp_log_flowend(tp);
1129 #endif
1130 	tp->t_acktime = 0;
1131 	return;
1132 }
1133 
1134 MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
1135 MALLOC_DEFINE(M_TCPFUNCTIONS, "tcpfunc", "TCP function set memory");
1136 
1137 static struct mtx isn_mtx;
1138 
1139 #define	ISN_LOCK_INIT()	mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF)
1140 #define	ISN_LOCK()	mtx_lock(&isn_mtx)
1141 #define	ISN_UNLOCK()	mtx_unlock(&isn_mtx)
1142 
1143 INPCBSTORAGE_DEFINE(tcpcbstor, tcpcb, "tcpinp", "tcp_inpcb", "tcphash");
1144 
1145 /*
1146  * Take a value and get the next power of 2 that doesn't overflow.
1147  * Used to size the tcp_inpcb hash buckets.
1148  */
1149 static int
1150 maketcp_hashsize(int size)
1151 {
1152 	int hashsize;
1153 
1154 	/*
1155 	 * auto tune.
1156 	 * get the next power of 2 higher than maxsockets.
1157 	 */
1158 	hashsize = 1 << fls(size);
1159 	/* catch overflow, and just go one power of 2 smaller */
1160 	if (hashsize < size) {
1161 		hashsize = 1 << (fls(size) - 1);
1162 	}
1163 	return (hashsize);
1164 }
1165 
1166 static volatile int next_tcp_stack_id = 1;
1167 
1168 /*
1169  * Register a TCP function block with the name provided in the names
1170  * array.  (Note that this function does NOT automatically register
1171  * blk->tfb_tcp_block_name as a stack name.  Therefore, you should
1172  * explicitly include blk->tfb_tcp_block_name in the list of names if
1173  * you wish to register the stack with that name.)
1174  *
1175  * Either all name registrations will succeed or all will fail.  If
1176  * a name registration fails, the function will update the num_names
1177  * argument to point to the array index of the name that encountered
1178  * the failure.
1179  *
1180  * Returns 0 on success, or an error code on failure.
1181  */
1182 int
1183 register_tcp_functions_as_names(struct tcp_function_block *blk, int wait,
1184     const char *names[], int *num_names)
1185 {
1186 	struct tcp_function *f[TCP_FUNCTION_NAME_NUM_MAX];
1187 	struct tcp_function_set fs;
1188 	int error, i, num_registered;
1189 
1190 	KASSERT(names != NULL, ("%s: Called with NULL name list", __func__));
1191 	KASSERT(*num_names > 0,
1192 	    ("%s: Called with non-positive length of name list", __func__));
1193 	KASSERT(rw_initialized(&tcp_function_lock),
1194 	    ("%s: called too early", __func__));
1195 
1196 	if (*num_names > TCP_FUNCTION_NAME_NUM_MAX) {
1197 		/* Too many names. */
1198 		*num_names = 0;
1199 		return (E2BIG);
1200 	}
1201 	if ((blk->tfb_tcp_output == NULL) ||
1202 	    (blk->tfb_tcp_do_segment == NULL) ||
1203 	    (blk->tfb_tcp_ctloutput == NULL) ||
1204 	    (blk->tfb_tcp_handoff_ok == NULL) ||
1205 	    (strlen(blk->tfb_tcp_block_name) == 0)) {
1206 		/* These functions are required and a name is needed. */
1207 		*num_names = 0;
1208 		return (EINVAL);
1209 	}
1210 
1211 	for (i = 0; i < *num_names; i++) {
1212 		f[i] = malloc(sizeof(struct tcp_function), M_TCPFUNCTIONS, wait);
1213 		if (f[i] == NULL) {
1214 			while (--i >= 0)
1215 				free(f[i], M_TCPFUNCTIONS);
1216 			*num_names = 0;
1217 			return (ENOMEM);
1218 		}
1219 	}
1220 
1221 	num_registered = 0;
1222 	rw_wlock(&tcp_function_lock);
1223 	if (find_tcp_fb_locked(blk, NULL) != NULL) {
1224 		/* A TCP function block can only be registered once. */
1225 		error = EALREADY;
1226 		goto cleanup;
1227 	}
1228 	if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
1229 		error = EINVAL;
1230 		goto cleanup;
1231 	}
1232 	refcount_init(&blk->tfb_refcnt, 0);
1233 	blk->tfb_id = atomic_fetchadd_int(&next_tcp_stack_id, 1);
1234 	for (i = 0; i < *num_names; i++) {
1235 		(void)strlcpy(fs.function_set_name, names[i],
1236 		    sizeof(fs.function_set_name));
1237 		if (find_tcp_functions_locked(&fs) != NULL) {
1238 			/* Duplicate name space not allowed */
1239 			error = EALREADY;
1240 			goto cleanup;
1241 		}
1242 		f[i]->tf_fb = blk;
1243 		(void)strlcpy(f[i]->tf_name, names[i], sizeof(f[i]->tf_name));
1244 		TAILQ_INSERT_TAIL(&t_functions, f[i], tf_next);
1245 		tcp_fb_cnt++;
1246 		num_registered++;
1247 	}
1248 	rw_wunlock(&tcp_function_lock);
1249 	return (0);
1250 
1251 cleanup:
1252 	/* Remove the entries just added. */
1253 	for (i = 0; i < *num_names; i++) {
1254 		if (i < num_registered) {
1255 			TAILQ_REMOVE(&t_functions, f[i], tf_next);
1256 			tcp_fb_cnt--;
1257 		}
1258 		f[i]->tf_fb = NULL;
1259 		free(f[i], M_TCPFUNCTIONS);
1260 	}
1261 	rw_wunlock(&tcp_function_lock);
1262 	*num_names = num_registered;
1263 	return (error);
1264 }
1265 
1266 /*
1267  * Register a TCP function block using the name provided in the name
1268  * argument.
1269  *
1270  * Returns 0 on success, or an error code on failure.
1271  */
1272 int
1273 register_tcp_functions_as_name(struct tcp_function_block *blk, const char *name,
1274     int wait)
1275 {
1276 	const char *name_list[1];
1277 	int num_names, rv;
1278 
1279 	num_names = 1;
1280 	if (name != NULL)
1281 		name_list[0] = name;
1282 	else
1283 		name_list[0] = blk->tfb_tcp_block_name;
1284 	rv = register_tcp_functions_as_names(blk, wait, name_list, &num_names);
1285 	return (rv);
1286 }
1287 
1288 /*
1289  * Register a TCP function block using the name defined in
1290  * blk->tfb_tcp_block_name.
1291  *
1292  * Returns 0 on success, or an error code on failure.
1293  */
1294 int
1295 register_tcp_functions(struct tcp_function_block *blk, int wait)
1296 {
1297 
1298 	return (register_tcp_functions_as_name(blk, NULL, wait));
1299 }
1300 
1301 /*
1302  * Deregister all names associated with a function block. This
1303  * functionally removes the function block from use within the system.
1304  *
1305  * When called with a true quiesce argument, mark the function block
1306  * as being removed so no more stacks will use it and determine
1307  * whether the removal would succeed.
1308  *
1309  * When called with a false quiesce argument, actually attempt the
1310  * removal.
1311  *
1312  * When called with a force argument, attempt to switch all TCBs to
1313  * use the default stack instead of returning EBUSY.
1314  *
1315  * Returns 0 on success (or if the removal would succeed), or an error
1316  * code on failure.
1317  */
1318 int
1319 deregister_tcp_functions(struct tcp_function_block *blk, bool quiesce,
1320     bool force)
1321 {
1322 	struct tcp_function *f;
1323 	VNET_ITERATOR_DECL(vnet_iter);
1324 
1325 	if (blk == &tcp_def_funcblk) {
1326 		/* You can't un-register the default */
1327 		return (EPERM);
1328 	}
1329 	rw_wlock(&tcp_function_lock);
1330 	VNET_LIST_RLOCK_NOSLEEP();
1331 	VNET_FOREACH(vnet_iter) {
1332 		CURVNET_SET(vnet_iter);
1333 		if (blk == V_tcp_func_set_ptr) {
1334 			/* You can't free the current default in some vnet. */
1335 			CURVNET_RESTORE();
1336 			VNET_LIST_RUNLOCK_NOSLEEP();
1337 			rw_wunlock(&tcp_function_lock);
1338 			return (EBUSY);
1339 		}
1340 		CURVNET_RESTORE();
1341 	}
1342 	VNET_LIST_RUNLOCK_NOSLEEP();
1343 	/* Mark the block so no more stacks can use it. */
1344 	blk->tfb_flags |= TCP_FUNC_BEING_REMOVED;
1345 	/*
1346 	 * If TCBs are still attached to the stack, attempt to switch them
1347 	 * to the default stack.
1348 	 */
1349 	if (force && blk->tfb_refcnt) {
1350 		struct inpcb *inp;
1351 		struct tcpcb *tp;
1352 		VNET_ITERATOR_DECL(vnet_iter);
1353 
1354 		rw_wunlock(&tcp_function_lock);
1355 
1356 		VNET_LIST_RLOCK();
1357 		VNET_FOREACH(vnet_iter) {
1358 			CURVNET_SET(vnet_iter);
1359 			struct inpcb_iterator inpi = INP_ALL_ITERATOR(&V_tcbinfo,
1360 			    INPLOOKUP_WLOCKPCB);
1361 
1362 			while ((inp = inp_next(&inpi)) != NULL) {
1363 				tp = intotcpcb(inp);
1364 				if (tp == NULL || tp->t_fb != blk)
1365 					continue;
1366 				tcp_switch_back_to_default(tp);
1367 			}
1368 			CURVNET_RESTORE();
1369 		}
1370 		VNET_LIST_RUNLOCK();
1371 
1372 		rw_wlock(&tcp_function_lock);
1373 	}
1374 	if (blk->tfb_refcnt) {
1375 		/* TCBs still attached. */
1376 		rw_wunlock(&tcp_function_lock);
1377 		return (EBUSY);
1378 	}
1379 	if (quiesce) {
1380 		/* Skip removal. */
1381 		rw_wunlock(&tcp_function_lock);
1382 		return (0);
1383 	}
1384 	/* Remove any function names that map to this function block. */
1385 	while (find_tcp_fb_locked(blk, &f) != NULL) {
1386 		TAILQ_REMOVE(&t_functions, f, tf_next);
1387 		tcp_fb_cnt--;
1388 		f->tf_fb = NULL;
1389 		free(f, M_TCPFUNCTIONS);
1390 	}
1391 	rw_wunlock(&tcp_function_lock);
1392 	return (0);
1393 }
1394 
1395 static void
1396 tcp_drain(void *ctx __unused, int flags __unused)
1397 {
1398 	struct epoch_tracker et;
1399 	VNET_ITERATOR_DECL(vnet_iter);
1400 
1401 	if (!do_tcpdrain)
1402 		return;
1403 
1404 	NET_EPOCH_ENTER(et);
1405 	VNET_LIST_RLOCK_NOSLEEP();
1406 	VNET_FOREACH(vnet_iter) {
1407 		CURVNET_SET(vnet_iter);
1408 		struct inpcb_iterator inpi = INP_ALL_ITERATOR(&V_tcbinfo,
1409 		    INPLOOKUP_WLOCKPCB);
1410 		struct inpcb *inpb;
1411 		struct tcpcb *tcpb;
1412 
1413 	/*
1414 	 * Walk the tcpbs, if existing, and flush the reassembly queue,
1415 	 * if there is one...
1416 	 * XXX: The "Net/3" implementation doesn't imply that the TCP
1417 	 *      reassembly queue should be flushed, but in a situation
1418 	 *	where we're really low on mbufs, this is potentially
1419 	 *	useful.
1420 	 */
1421 		while ((inpb = inp_next(&inpi)) != NULL) {
1422 			if ((tcpb = intotcpcb(inpb)) != NULL) {
1423 				tcp_reass_flush(tcpb);
1424 				tcp_clean_sackreport(tcpb);
1425 #ifdef TCP_BLACKBOX
1426 				tcp_log_drain(tcpb);
1427 #endif
1428 			}
1429 		}
1430 		CURVNET_RESTORE();
1431 	}
1432 	VNET_LIST_RUNLOCK_NOSLEEP();
1433 	NET_EPOCH_EXIT(et);
1434 }
1435 
1436 static void
1437 tcp_vnet_init(void *arg __unused)
1438 {
1439 
1440 #ifdef TCP_HHOOK
1441 	if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN,
1442 	    &V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
1443 		printf("%s: WARNING: unable to register helper hook\n", __func__);
1444 	if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT,
1445 	    &V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
1446 		printf("%s: WARNING: unable to register helper hook\n", __func__);
1447 #endif
1448 #ifdef STATS
1449 	if (tcp_stats_init())
1450 		printf("%s: WARNING: unable to initialise TCP stats\n",
1451 		    __func__);
1452 #endif
1453 	in_pcbinfo_init(&V_tcbinfo, &tcpcbstor, tcp_tcbhashsize,
1454 	    tcp_tcbhashsize);
1455 
1456 	syncache_init();
1457 	tcp_hc_init();
1458 
1459 	TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
1460 	V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
1461 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
1462 
1463 	tcp_fastopen_init();
1464 
1465 	COUNTER_ARRAY_ALLOC(V_tcps_states, TCP_NSTATES, M_WAITOK);
1466 	VNET_PCPUSTAT_ALLOC(tcpstat, M_WAITOK);
1467 
1468 	V_tcp_msl = TCPTV_MSL;
1469 	V_tcp_msl_local = TCPTV_MSL_LOCAL;
1470 	arc4rand(&V_ts_offset_secret, sizeof(V_ts_offset_secret), 0);
1471 }
1472 VNET_SYSINIT(tcp_vnet_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
1473     tcp_vnet_init, NULL);
1474 
1475 static void
1476 tcp_init(void *arg __unused)
1477 {
1478 	int hashsize;
1479 
1480 	tcp_reass_global_init();
1481 
1482 	/* XXX virtualize those below? */
1483 	tcp_delacktime = TCPTV_DELACK;
1484 	tcp_keepinit = TCPTV_KEEP_INIT;
1485 	tcp_keepidle = TCPTV_KEEP_IDLE;
1486 	tcp_keepintvl = TCPTV_KEEPINTVL;
1487 	tcp_maxpersistidle = TCPTV_KEEP_IDLE;
1488 	tcp_rexmit_initial = TCPTV_RTOBASE;
1489 	tcp_rexmit_min = TCPTV_MIN;
1490 	tcp_rexmit_max = TCPTV_REXMTMAX;
1491 	tcp_persmin = TCPTV_PERSMIN;
1492 	tcp_persmax = TCPTV_PERSMAX;
1493 	tcp_rexmit_slop = TCPTV_CPU_VAR;
1494 	tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
1495 
1496 	/* Setup the tcp function block list */
1497 	TAILQ_INIT(&t_functions);
1498 	rw_init(&tcp_function_lock, "tcp_func_lock");
1499 	register_tcp_functions(&tcp_def_funcblk, M_WAITOK);
1500 	sx_init(&tcpoudp_lock, "TCP over UDP configuration");
1501 #ifdef TCP_BLACKBOX
1502 	/* Initialize the TCP logging data. */
1503 	tcp_log_init();
1504 #endif
1505 
1506 	if (tcp_soreceive_stream) {
1507 #ifdef INET
1508 		tcp_protosw.pr_soreceive = soreceive_stream;
1509 #endif
1510 #ifdef INET6
1511 		tcp6_protosw.pr_soreceive = soreceive_stream;
1512 #endif /* INET6 */
1513 	}
1514 
1515 #ifdef INET6
1516 	max_protohdr_grow(sizeof(struct ip6_hdr) + sizeof(struct tcphdr));
1517 #else /* INET6 */
1518 	max_protohdr_grow(sizeof(struct tcpiphdr));
1519 #endif /* INET6 */
1520 
1521 	ISN_LOCK_INIT();
1522 	EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
1523 		SHUTDOWN_PRI_DEFAULT);
1524 	EVENTHANDLER_REGISTER(vm_lowmem, tcp_drain, NULL, LOWMEM_PRI_DEFAULT);
1525 	EVENTHANDLER_REGISTER(mbuf_lowmem, tcp_drain, NULL, LOWMEM_PRI_DEFAULT);
1526 
1527 	tcp_inp_lro_direct_queue = counter_u64_alloc(M_WAITOK);
1528 	tcp_inp_lro_wokeup_queue = counter_u64_alloc(M_WAITOK);
1529 	tcp_inp_lro_compressed = counter_u64_alloc(M_WAITOK);
1530 	tcp_inp_lro_locks_taken = counter_u64_alloc(M_WAITOK);
1531 	tcp_extra_mbuf = counter_u64_alloc(M_WAITOK);
1532 	tcp_would_have_but = counter_u64_alloc(M_WAITOK);
1533 	tcp_comp_total = counter_u64_alloc(M_WAITOK);
1534 	tcp_uncomp_total = counter_u64_alloc(M_WAITOK);
1535 	tcp_bad_csums = counter_u64_alloc(M_WAITOK);
1536 	tcp_pacing_failures = counter_u64_alloc(M_WAITOK);
1537 	tcp_dgp_failures = counter_u64_alloc(M_WAITOK);
1538 
1539 	hashsize = tcp_tcbhashsize;
1540 	if (hashsize == 0) {
1541 		/*
1542 		 * Auto tune the hash size based on maxsockets.
1543 		 * A perfect hash would have a 1:1 mapping
1544 		 * (hashsize = maxsockets) however it's been
1545 		 * suggested that O(2) average is better.
1546 		 */
1547 		hashsize = maketcp_hashsize(maxsockets / 4);
1548 		/*
1549 		 * Our historical default is 512,
1550 		 * do not autotune lower than this.
1551 		 */
1552 		if (hashsize < 512)
1553 			hashsize = 512;
1554 		if (bootverbose)
1555 			printf("%s: %s auto tuned to %d\n", __func__,
1556 			    "net.inet.tcp.tcbhashsize", hashsize);
1557 	}
1558 	/*
1559 	 * We require a hashsize to be a power of two.
1560 	 * Previously if it was not a power of two we would just reset it
1561 	 * back to 512, which could be a nasty surprise if you did not notice
1562 	 * the error message.
1563 	 * Instead what we do is clip it to the closest power of two lower
1564 	 * than the specified hash value.
1565 	 */
1566 	if (!powerof2(hashsize)) {
1567 		int oldhashsize = hashsize;
1568 
1569 		hashsize = maketcp_hashsize(hashsize);
1570 		/* prevent absurdly low value */
1571 		if (hashsize < 16)
1572 			hashsize = 16;
1573 		printf("%s: WARNING: TCB hash size not a power of 2, "
1574 		    "clipped from %d to %d.\n", __func__, oldhashsize,
1575 		    hashsize);
1576 	}
1577 	tcp_tcbhashsize = hashsize;
1578 
1579 #ifdef INET
1580 	IPPROTO_REGISTER(IPPROTO_TCP, tcp_input, tcp_ctlinput);
1581 #endif
1582 #ifdef INET6
1583 	IP6PROTO_REGISTER(IPPROTO_TCP, tcp6_input, tcp6_ctlinput);
1584 #endif
1585 }
1586 SYSINIT(tcp_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, tcp_init, NULL);
1587 
1588 #ifdef VIMAGE
1589 static void
1590 tcp_destroy(void *unused __unused)
1591 {
1592 #ifdef TCP_HHOOK
1593 	int error;
1594 #endif
1595 
1596 	tcp_hc_destroy();
1597 	syncache_destroy();
1598 	in_pcbinfo_destroy(&V_tcbinfo);
1599 	/* tcp_discardcb() clears the sack_holes up. */
1600 	uma_zdestroy(V_sack_hole_zone);
1601 
1602 	/*
1603 	 * Cannot free the zone until all tcpcbs are released as we attach
1604 	 * the allocations to them.
1605 	 */
1606 	tcp_fastopen_destroy();
1607 
1608 	COUNTER_ARRAY_FREE(V_tcps_states, TCP_NSTATES);
1609 	VNET_PCPUSTAT_FREE(tcpstat);
1610 
1611 #ifdef TCP_HHOOK
1612 	error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_IN]);
1613 	if (error != 0) {
1614 		printf("%s: WARNING: unable to deregister helper hook "
1615 		    "type=%d, id=%d: error %d returned\n", __func__,
1616 		    HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN, error);
1617 	}
1618 	error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_OUT]);
1619 	if (error != 0) {
1620 		printf("%s: WARNING: unable to deregister helper hook "
1621 		    "type=%d, id=%d: error %d returned\n", __func__,
1622 		    HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT, error);
1623 	}
1624 #endif
1625 }
1626 VNET_SYSUNINIT(tcp, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH, tcp_destroy, NULL);
1627 #endif
1628 
1629 void
1630 tcp_fini(void *xtp)
1631 {
1632 
1633 }
1634 
1635 /*
1636  * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
1637  * tcp_template used to store this data in mbufs, but we now recopy it out
1638  * of the tcpcb each time to conserve mbufs.
1639  */
1640 void
1641 tcpip_fillheaders(struct inpcb *inp, uint16_t port, void *ip_ptr, void *tcp_ptr)
1642 {
1643 	struct tcphdr *th = (struct tcphdr *)tcp_ptr;
1644 
1645 	INP_WLOCK_ASSERT(inp);
1646 
1647 #ifdef INET6
1648 	if ((inp->inp_vflag & INP_IPV6) != 0) {
1649 		struct ip6_hdr *ip6;
1650 
1651 		ip6 = (struct ip6_hdr *)ip_ptr;
1652 		ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
1653 			(inp->inp_flow & IPV6_FLOWINFO_MASK);
1654 		ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
1655 			(IPV6_VERSION & IPV6_VERSION_MASK);
1656 		if (port == 0)
1657 			ip6->ip6_nxt = IPPROTO_TCP;
1658 		else
1659 			ip6->ip6_nxt = IPPROTO_UDP;
1660 		ip6->ip6_plen = htons(sizeof(struct tcphdr));
1661 		ip6->ip6_src = inp->in6p_laddr;
1662 		ip6->ip6_dst = inp->in6p_faddr;
1663 	}
1664 #endif /* INET6 */
1665 #if defined(INET6) && defined(INET)
1666 	else
1667 #endif
1668 #ifdef INET
1669 	{
1670 		struct ip *ip;
1671 
1672 		ip = (struct ip *)ip_ptr;
1673 		ip->ip_v = IPVERSION;
1674 		ip->ip_hl = 5;
1675 		ip->ip_tos = inp->inp_ip_tos;
1676 		ip->ip_len = 0;
1677 		ip->ip_id = 0;
1678 		ip->ip_off = 0;
1679 		ip->ip_ttl = inp->inp_ip_ttl;
1680 		ip->ip_sum = 0;
1681 		if (port == 0)
1682 			ip->ip_p = IPPROTO_TCP;
1683 		else
1684 			ip->ip_p = IPPROTO_UDP;
1685 		ip->ip_src = inp->inp_laddr;
1686 		ip->ip_dst = inp->inp_faddr;
1687 	}
1688 #endif /* INET */
1689 	th->th_sport = inp->inp_lport;
1690 	th->th_dport = inp->inp_fport;
1691 	th->th_seq = 0;
1692 	th->th_ack = 0;
1693 	th->th_off = 5;
1694 	tcp_set_flags(th, 0);
1695 	th->th_win = 0;
1696 	th->th_urp = 0;
1697 	th->th_sum = 0;		/* in_pseudo() is called later for ipv4 */
1698 }
1699 
1700 /*
1701  * Create template to be used to send tcp packets on a connection.
1702  * Allocates an mbuf and fills in a skeletal tcp/ip header.  The only
1703  * use for this function is in keepalives, which use tcp_respond.
1704  */
1705 struct tcptemp *
1706 tcpip_maketemplate(struct inpcb *inp)
1707 {
1708 	struct tcptemp *t;
1709 
1710 	t = malloc(sizeof(*t), M_TEMP, M_NOWAIT);
1711 	if (t == NULL)
1712 		return (NULL);
1713 	tcpip_fillheaders(inp, 0, (void *)&t->tt_ipgen, (void *)&t->tt_t);
1714 	return (t);
1715 }
1716 
1717 /*
1718  * Send a single message to the TCP at address specified by
1719  * the given TCP/IP header.  If m == NULL, then we make a copy
1720  * of the tcpiphdr at th and send directly to the addressed host.
1721  * This is used to force keep alive messages out using the TCP
1722  * template for a connection.  If flags are given then we send
1723  * a message back to the TCP which originated the segment th,
1724  * and discard the mbuf containing it and any other attached mbufs.
1725  *
1726  * In any case the ack and sequence number of the transmitted
1727  * segment are as specified by the parameters.
1728  *
1729  * NOTE: If m != NULL, then th must point to *inside* the mbuf.
1730  */
1731 
1732 void
1733 tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
1734     tcp_seq ack, tcp_seq seq, uint16_t flags)
1735 {
1736 	struct tcpopt to;
1737 	struct inpcb *inp;
1738 	struct ip *ip;
1739 	struct mbuf *optm;
1740 	struct udphdr *uh = NULL;
1741 	struct tcphdr *nth;
1742 	struct tcp_log_buffer *lgb;
1743 	u_char *optp;
1744 #ifdef INET6
1745 	struct ip6_hdr *ip6;
1746 	int isipv6;
1747 #endif /* INET6 */
1748 	int optlen, tlen, win, ulen;
1749 	int ect = 0;
1750 	bool incl_opts;
1751 	uint16_t port;
1752 	int output_ret;
1753 #ifdef INVARIANTS
1754 	int thflags = tcp_get_flags(th);
1755 #endif
1756 
1757 	KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
1758 	NET_EPOCH_ASSERT();
1759 
1760 #ifdef INET6
1761 	isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4);
1762 	ip6 = ipgen;
1763 #endif /* INET6 */
1764 	ip = ipgen;
1765 
1766 	if (tp != NULL) {
1767 		inp = tptoinpcb(tp);
1768 		INP_LOCK_ASSERT(inp);
1769 	} else
1770 		inp = NULL;
1771 
1772 	if (m != NULL) {
1773 #ifdef INET6
1774 		if (isipv6 && ip6 && (ip6->ip6_nxt == IPPROTO_UDP))
1775 			port = m->m_pkthdr.tcp_tun_port;
1776 		else
1777 #endif
1778 		if (ip && (ip->ip_p == IPPROTO_UDP))
1779 			port = m->m_pkthdr.tcp_tun_port;
1780 		else
1781 			port = 0;
1782 	} else
1783 		port = tp->t_port;
1784 
1785 	incl_opts = false;
1786 	win = 0;
1787 	if (tp != NULL) {
1788 		if (!(flags & TH_RST)) {
1789 			win = sbspace(&inp->inp_socket->so_rcv);
1790 			if (win > TCP_MAXWIN << tp->rcv_scale)
1791 				win = TCP_MAXWIN << tp->rcv_scale;
1792 		}
1793 		if ((tp->t_flags & TF_NOOPT) == 0)
1794 			incl_opts = true;
1795 	}
1796 	if (m == NULL) {
1797 		m = m_gethdr(M_NOWAIT, MT_DATA);
1798 		if (m == NULL)
1799 			return;
1800 		m->m_data += max_linkhdr;
1801 #ifdef INET6
1802 		if (isipv6) {
1803 			bcopy((caddr_t)ip6, mtod(m, caddr_t),
1804 			      sizeof(struct ip6_hdr));
1805 			ip6 = mtod(m, struct ip6_hdr *);
1806 			nth = (struct tcphdr *)(ip6 + 1);
1807 			if (port) {
1808 				/* Insert a UDP header */
1809 				uh = (struct udphdr *)nth;
1810 				uh->uh_sport = htons(V_tcp_udp_tunneling_port);
1811 				uh->uh_dport = port;
1812 				nth = (struct tcphdr *)(uh + 1);
1813 			}
1814 		} else
1815 #endif /* INET6 */
1816 		{
1817 			bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
1818 			ip = mtod(m, struct ip *);
1819 			nth = (struct tcphdr *)(ip + 1);
1820 			if (port) {
1821 				/* Insert a UDP header */
1822 				uh = (struct udphdr *)nth;
1823 				uh->uh_sport = htons(V_tcp_udp_tunneling_port);
1824 				uh->uh_dport = port;
1825 				nth = (struct tcphdr *)(uh + 1);
1826 			}
1827 		}
1828 		bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
1829 		flags = TH_ACK;
1830 	} else if ((!M_WRITABLE(m)) || (port != 0)) {
1831 		struct mbuf *n;
1832 
1833 		/* Can't reuse 'm', allocate a new mbuf. */
1834 		n = m_gethdr(M_NOWAIT, MT_DATA);
1835 		if (n == NULL) {
1836 			m_freem(m);
1837 			return;
1838 		}
1839 
1840 		if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
1841 			m_freem(m);
1842 			m_freem(n);
1843 			return;
1844 		}
1845 
1846 		n->m_data += max_linkhdr;
1847 		/* m_len is set later */
1848 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
1849 #ifdef INET6
1850 		if (isipv6) {
1851 			bcopy((caddr_t)ip6, mtod(n, caddr_t),
1852 			      sizeof(struct ip6_hdr));
1853 			ip6 = mtod(n, struct ip6_hdr *);
1854 			xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
1855 			nth = (struct tcphdr *)(ip6 + 1);
1856 			if (port) {
1857 				/* Insert a UDP header */
1858 				uh = (struct udphdr *)nth;
1859 				uh->uh_sport = htons(V_tcp_udp_tunneling_port);
1860 				uh->uh_dport = port;
1861 				nth = (struct tcphdr *)(uh + 1);
1862 			}
1863 		} else
1864 #endif /* INET6 */
1865 		{
1866 			bcopy((caddr_t)ip, mtod(n, caddr_t), sizeof(struct ip));
1867 			ip = mtod(n, struct ip *);
1868 			xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
1869 			nth = (struct tcphdr *)(ip + 1);
1870 			if (port) {
1871 				/* Insert a UDP header */
1872 				uh = (struct udphdr *)nth;
1873 				uh->uh_sport = htons(V_tcp_udp_tunneling_port);
1874 				uh->uh_dport = port;
1875 				nth = (struct tcphdr *)(uh + 1);
1876 			}
1877 		}
1878 		bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
1879 		xchg(nth->th_dport, nth->th_sport, uint16_t);
1880 		th = nth;
1881 		m_freem(m);
1882 		m = n;
1883 	} else {
1884 		/*
1885 		 *  reuse the mbuf.
1886 		 * XXX MRT We inherit the FIB, which is lucky.
1887 		 */
1888 		m_freem(m->m_next);
1889 		m->m_next = NULL;
1890 		m->m_data = (caddr_t)ipgen;
1891 		/* clear any receive flags for proper bpf timestamping */
1892 		m->m_flags &= ~(M_TSTMP | M_TSTMP_LRO);
1893 		/* m_len is set later */
1894 #ifdef INET6
1895 		if (isipv6) {
1896 			xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
1897 			nth = (struct tcphdr *)(ip6 + 1);
1898 		} else
1899 #endif /* INET6 */
1900 		{
1901 			xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
1902 			nth = (struct tcphdr *)(ip + 1);
1903 		}
1904 		if (th != nth) {
1905 			/*
1906 			 * this is usually a case when an extension header
1907 			 * exists between the IPv6 header and the
1908 			 * TCP header.
1909 			 */
1910 			nth->th_sport = th->th_sport;
1911 			nth->th_dport = th->th_dport;
1912 		}
1913 		xchg(nth->th_dport, nth->th_sport, uint16_t);
1914 #undef xchg
1915 	}
1916 	tlen = 0;
1917 #ifdef INET6
1918 	if (isipv6)
1919 		tlen = sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
1920 #endif
1921 #if defined(INET) && defined(INET6)
1922 	else
1923 #endif
1924 #ifdef INET
1925 		tlen = sizeof (struct tcpiphdr);
1926 #endif
1927 	if (port)
1928 		tlen += sizeof (struct udphdr);
1929 #ifdef INVARIANTS
1930 	m->m_len = 0;
1931 	KASSERT(M_TRAILINGSPACE(m) >= tlen,
1932 	    ("Not enough trailing space for message (m=%p, need=%d, have=%ld)",
1933 	    m, tlen, (long)M_TRAILINGSPACE(m)));
1934 #endif
1935 	m->m_len = tlen;
1936 	to.to_flags = 0;
1937 	if (incl_opts) {
1938 		ect = tcp_ecn_output_established(tp, &flags, 0, false);
1939 		/* Make sure we have room. */
1940 		if (M_TRAILINGSPACE(m) < TCP_MAXOLEN) {
1941 			m->m_next = m_get(M_NOWAIT, MT_DATA);
1942 			if (m->m_next) {
1943 				optp = mtod(m->m_next, u_char *);
1944 				optm = m->m_next;
1945 			} else
1946 				incl_opts = false;
1947 		} else {
1948 			optp = (u_char *) (nth + 1);
1949 			optm = m;
1950 		}
1951 	}
1952 	if (incl_opts) {
1953 		/* Timestamps. */
1954 		if (tp->t_flags & TF_RCVD_TSTMP) {
1955 			to.to_tsval = tcp_ts_getticks() + tp->ts_offset;
1956 			to.to_tsecr = tp->ts_recent;
1957 			to.to_flags |= TOF_TS;
1958 		}
1959 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
1960 		/* TCP-MD5 (RFC2385). */
1961 		if (tp->t_flags & TF_SIGNATURE)
1962 			to.to_flags |= TOF_SIGNATURE;
1963 #endif
1964 		/* Add the options. */
1965 		tlen += optlen = tcp_addoptions(&to, optp);
1966 
1967 		/* Update m_len in the correct mbuf. */
1968 		optm->m_len += optlen;
1969 	} else
1970 		optlen = 0;
1971 #ifdef INET6
1972 	if (isipv6) {
1973 		if (uh) {
1974 			ulen = tlen - sizeof(struct ip6_hdr);
1975 			uh->uh_ulen = htons(ulen);
1976 		}
1977 		ip6->ip6_flow = htonl(ect << IPV6_FLOWLABEL_LEN);
1978 		ip6->ip6_vfc = IPV6_VERSION;
1979 		if (port)
1980 			ip6->ip6_nxt = IPPROTO_UDP;
1981 		else
1982 			ip6->ip6_nxt = IPPROTO_TCP;
1983 		ip6->ip6_plen = htons(tlen - sizeof(*ip6));
1984 	}
1985 #endif
1986 #if defined(INET) && defined(INET6)
1987 	else
1988 #endif
1989 #ifdef INET
1990 	{
1991 		if (uh) {
1992 			ulen = tlen - sizeof(struct ip);
1993 			uh->uh_ulen = htons(ulen);
1994 		}
1995 		ip->ip_len = htons(tlen);
1996 		if (inp != NULL) {
1997 			ip->ip_tos = inp->inp_ip_tos & ~IPTOS_ECN_MASK;
1998 			ip->ip_ttl = inp->inp_ip_ttl;
1999 		} else {
2000 			ip->ip_tos = 0;
2001 			ip->ip_ttl = V_ip_defttl;
2002 		}
2003 		ip->ip_tos |= ect;
2004 		if (port) {
2005 			ip->ip_p = IPPROTO_UDP;
2006 		} else {
2007 			ip->ip_p = IPPROTO_TCP;
2008 		}
2009 		if (V_path_mtu_discovery)
2010 			ip->ip_off |= htons(IP_DF);
2011 	}
2012 #endif
2013 	m->m_pkthdr.len = tlen;
2014 	m->m_pkthdr.rcvif = NULL;
2015 #ifdef MAC
2016 	if (inp != NULL) {
2017 		/*
2018 		 * Packet is associated with a socket, so allow the
2019 		 * label of the response to reflect the socket label.
2020 		 */
2021 		INP_LOCK_ASSERT(inp);
2022 		mac_inpcb_create_mbuf(inp, m);
2023 	} else {
2024 		/*
2025 		 * Packet is not associated with a socket, so possibly
2026 		 * update the label in place.
2027 		 */
2028 		mac_netinet_tcp_reply(m);
2029 	}
2030 #endif
2031 	nth->th_seq = htonl(seq);
2032 	nth->th_ack = htonl(ack);
2033 	nth->th_off = (sizeof (struct tcphdr) + optlen) >> 2;
2034 	tcp_set_flags(nth, flags);
2035 	if (tp && (flags & TH_RST)) {
2036 		/* Log the reset */
2037 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
2038 	}
2039 	if (tp != NULL)
2040 		nth->th_win = htons((u_short) (win >> tp->rcv_scale));
2041 	else
2042 		nth->th_win = htons((u_short)win);
2043 	nth->th_urp = 0;
2044 
2045 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
2046 	if (to.to_flags & TOF_SIGNATURE) {
2047 		if (!TCPMD5_ENABLED() ||
2048 		    TCPMD5_OUTPUT(m, nth, to.to_signature) != 0) {
2049 			m_freem(m);
2050 			return;
2051 		}
2052 	}
2053 #endif
2054 
2055 #ifdef INET6
2056 	if (isipv6) {
2057 		if (port) {
2058 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
2059 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
2060 			uh->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
2061 			nth->th_sum = 0;
2062 		} else {
2063 			m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
2064 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
2065 			nth->th_sum = in6_cksum_pseudo(ip6,
2066 			    tlen - sizeof(struct ip6_hdr), IPPROTO_TCP, 0);
2067 		}
2068 		ip6->ip6_hlim = in6_selecthlim(inp, NULL);
2069 	}
2070 #endif /* INET6 */
2071 #if defined(INET6) && defined(INET)
2072 	else
2073 #endif
2074 #ifdef INET
2075 	{
2076 		if (port) {
2077 			uh->uh_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
2078 			    htons(ulen + IPPROTO_UDP));
2079 			m->m_pkthdr.csum_flags = CSUM_UDP;
2080 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
2081 			nth->th_sum = 0;
2082 		} else {
2083 			m->m_pkthdr.csum_flags = CSUM_TCP;
2084 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
2085 			nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
2086 			    htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
2087 		}
2088 	}
2089 #endif /* INET */
2090 	TCP_PROBE3(debug__output, tp, th, m);
2091 	if (flags & TH_RST)
2092 		TCP_PROBE5(accept__refused, NULL, NULL, m, tp, nth);
2093 	lgb = NULL;
2094 	if ((tp != NULL) && tcp_bblogging_on(tp)) {
2095 		if (INP_WLOCKED(inp)) {
2096 			union tcp_log_stackspecific log;
2097 			struct timeval tv;
2098 
2099 			memset(&log, 0, sizeof(log));
2100 			log.u_bbr.inhpts = tcp_in_hpts(tp);
2101 			log.u_bbr.flex8 = 4;
2102 			log.u_bbr.pkts_out = tp->t_maxseg;
2103 			log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2104 			log.u_bbr.delivered = 0;
2105 			lgb = tcp_log_event(tp, nth, NULL, NULL, TCP_LOG_OUT,
2106 			    ERRNO_UNK, 0, &log, false, NULL, NULL, 0, &tv);
2107 		} else {
2108 			/*
2109 			 * We can not log the packet, since we only own the
2110 			 * read lock, but a write lock is needed. The read lock
2111 			 * is not upgraded to a write lock, since only getting
2112 			 * the read lock was done intentionally to improve the
2113 			 * handling of SYN flooding attacks.
2114 			 * This happens only for pure SYN segments received in
2115 			 * the initial CLOSED state, or received in a more
2116 			 * advanced state than listen and the UDP encapsulation
2117 			 * port is unexpected.
2118 			 * The incoming SYN segments do not really belong to
2119 			 * the TCP connection and the handling does not change
2120 			 * the state of the TCP connection. Therefore, the
2121 			 * sending of the RST segments is not logged. Please
2122 			 * note that also the incoming SYN segments are not
2123 			 * logged.
2124 			 *
2125 			 * The following code ensures that the above description
2126 			 * is and stays correct.
2127 			 */
2128 			KASSERT((thflags & (TH_ACK|TH_SYN)) == TH_SYN &&
2129 			    (tp->t_state == TCPS_CLOSED ||
2130 			    (tp->t_state > TCPS_LISTEN && tp->t_port != port)),
2131 			    ("%s: Logging of TCP segment with flags 0x%b and "
2132 			    "UDP encapsulation port %u skipped in state %s",
2133 			    __func__, thflags, PRINT_TH_FLAGS,
2134 			    ntohs(port), tcpstates[tp->t_state]));
2135 		}
2136 	}
2137 
2138 	if (flags & TH_ACK)
2139 		TCPSTAT_INC(tcps_sndacks);
2140 	else if (flags & (TH_SYN|TH_FIN|TH_RST))
2141 		TCPSTAT_INC(tcps_sndctrl);
2142 	TCPSTAT_INC(tcps_sndtotal);
2143 
2144 #ifdef INET6
2145 	if (isipv6) {
2146 		TCP_PROBE5(send, NULL, tp, ip6, tp, nth);
2147 		output_ret = ip6_output(m, inp ? inp->in6p_outputopts : NULL,
2148 		    NULL, 0, NULL, NULL, inp);
2149 	}
2150 #endif /* INET6 */
2151 #if defined(INET) && defined(INET6)
2152 	else
2153 #endif
2154 #ifdef INET
2155 	{
2156 		TCP_PROBE5(send, NULL, tp, ip, tp, nth);
2157 		output_ret = ip_output(m, NULL, NULL, 0, NULL, inp);
2158 	}
2159 #endif
2160 	if (lgb != NULL)
2161 		lgb->tlb_errno = output_ret;
2162 }
2163 
2164 /*
2165  * Check that no more than V_tcp_ack_war_cnt per V_tcp_ack_war_time_window
2166  * are sent. *epoch_end is the end of the current epoch and is updated, if the
2167  * current epoch ended in the past. *ack_cnt is the counter used during the
2168  * current epoch. It might be reset and incremented.
2169  * The function returns true if a challenge ACK should be sent.
2170  */
2171 bool
2172 tcp_challenge_ack_check(sbintime_t *epoch_end, uint32_t *ack_cnt)
2173 {
2174 	sbintime_t now;
2175 
2176 	/*
2177 	 * The sending of a challenge ACK could be triggered by a blind attacker
2178 	 * to detect an existing TCP connection. To mitigate that, increment
2179 	 * also the global counter which would be incremented if the attacker
2180 	 * would have guessed wrongly.
2181 	 */
2182 	(void)badport_bandlim(BANDLIM_TCP_RST);
2183 
2184 	if (V_tcp_ack_war_time_window == 0 || V_tcp_ack_war_cnt == 0) {
2185 		/* ACK war protection is disabled. */
2186 		return (true);
2187 	} else {
2188 		/* Start new epoch, if the previous one is already over. */
2189 		now = getsbinuptime();
2190 		if (*epoch_end < now) {
2191 			*ack_cnt = 0;
2192 			*epoch_end = now + V_tcp_ack_war_time_window * SBT_1MS;
2193 		}
2194 		/*
2195 		 * Send a challenge ACK, if less than tcp_ack_war_cnt have been
2196 		 * sent in the current epoch.
2197 		 */
2198 		if (*ack_cnt < V_tcp_ack_war_cnt) {
2199 			(*ack_cnt)++;
2200 			return (true);
2201 		} else {
2202 			return (false);
2203 		}
2204 	}
2205 }
2206 
2207 /*
2208  * Send a challenge ack (no data, no SACK option), but not more than
2209  * V_tcp_ack_war_cnt per V_tcp_ack_war_time_window (per TCP connection).
2210  */
2211 void
2212 tcp_send_challenge_ack(struct tcpcb *tp, struct tcphdr *th, struct mbuf *m)
2213 {
2214 	if (tcp_challenge_ack_check(&tp->t_challenge_ack_end,
2215 	    &tp->t_challenge_ack_cnt)) {
2216 		tcp_respond(tp, mtod(m, void *), th, m, tp->rcv_nxt,
2217 		    tp->snd_nxt, TH_ACK);
2218 		tp->last_ack_sent = tp->rcv_nxt;
2219 	} else {
2220 		m_freem(m);
2221 	}
2222 }
2223 
2224 /*
2225  * Create a new TCP control block, making an empty reassembly queue and hooking
2226  * it to the argument protocol control block.  The `inp' parameter must have
2227  * come from the zone allocator set up by tcpcbstor declaration.
2228  * The caller can provide a pointer to a tcpcb of the listener to inherit the
2229  * TCP function block from the listener.
2230  */
2231 struct tcpcb *
2232 tcp_newtcpcb(struct inpcb *inp, struct tcpcb *listening_tcb)
2233 {
2234 	struct tcpcb *tp = intotcpcb(inp);
2235 #ifdef INET6
2236 	int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
2237 #endif /* INET6 */
2238 
2239 	/*
2240 	 * Historically allocation was done with M_ZERO.  There is a lot of
2241 	 * code that rely on that.  For now take safe approach and zero whole
2242 	 * tcpcb.  This definitely can be optimized.
2243 	 */
2244 	bzero(&tp->t_start_zero, t_zero_size);
2245 
2246 	/* Initialise cc_var struct for this tcpcb. */
2247 	tp->t_ccv.tp = tp;
2248 	rw_rlock(&tcp_function_lock);
2249 	if (listening_tcb != NULL) {
2250 		INP_LOCK_ASSERT(tptoinpcb(listening_tcb));
2251 		KASSERT(listening_tcb->t_fb != NULL,
2252 		    ("tcp_newtcpcb: listening_tcb->t_fb is NULL"));
2253 		if (listening_tcb->t_fb->tfb_flags & TCP_FUNC_BEING_REMOVED) {
2254 			rw_runlock(&tcp_function_lock);
2255 			return (NULL);
2256 		}
2257 		tp->t_fb = listening_tcb->t_fb;
2258 	} else {
2259 		tp->t_fb = V_tcp_func_set_ptr;
2260 	}
2261 	refcount_acquire(&tp->t_fb->tfb_refcnt);
2262 	KASSERT((tp->t_fb->tfb_flags & TCP_FUNC_BEING_REMOVED) == 0,
2263 	    ("tcp_newtcpcb: using TFB being removed"));
2264 	rw_runlock(&tcp_function_lock);
2265 	CC_LIST_RLOCK();
2266 	if (listening_tcb != NULL) {
2267 		if (CC_ALGO(listening_tcb)->flags & CC_MODULE_BEING_REMOVED) {
2268 			CC_LIST_RUNLOCK();
2269 			if (tp->t_fb->tfb_tcp_fb_fini)
2270 				(*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
2271 			refcount_release(&tp->t_fb->tfb_refcnt);
2272 			return (NULL);
2273 		}
2274 		CC_ALGO(tp) = CC_ALGO(listening_tcb);
2275 	} else
2276 		CC_ALGO(tp) = CC_DEFAULT_ALGO();
2277 	cc_refer(CC_ALGO(tp));
2278 	CC_LIST_RUNLOCK();
2279 	if (CC_ALGO(tp)->cb_init != NULL)
2280 		if (CC_ALGO(tp)->cb_init(&tp->t_ccv, NULL) > 0) {
2281 			cc_detach(tp);
2282 			if (tp->t_fb->tfb_tcp_fb_fini)
2283 				(*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
2284 			refcount_release(&tp->t_fb->tfb_refcnt);
2285 			return (NULL);
2286 		}
2287 
2288 #ifdef TCP_HHOOK
2289 	if (khelp_init_osd(HELPER_CLASS_TCP, &tp->t_osd)) {
2290 		if (CC_ALGO(tp)->cb_destroy != NULL)
2291 			CC_ALGO(tp)->cb_destroy(&tp->t_ccv);
2292 		CC_DATA(tp) = NULL;
2293 		cc_detach(tp);
2294 		if (tp->t_fb->tfb_tcp_fb_fini)
2295 			(*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
2296 		refcount_release(&tp->t_fb->tfb_refcnt);
2297 		return (NULL);
2298 	}
2299 #endif
2300 
2301 	TAILQ_INIT(&tp->t_segq);
2302 	STAILQ_INIT(&tp->t_inqueue);
2303 	tp->t_maxseg =
2304 #ifdef INET6
2305 		isipv6 ? V_tcp_v6mssdflt :
2306 #endif /* INET6 */
2307 		V_tcp_mssdflt;
2308 
2309 	/* All mbuf queue/ack compress flags should be off */
2310 	tcp_lro_features_off(tp);
2311 
2312 	tp->t_hpts_cpu = HPTS_CPU_NONE;
2313 	tp->t_lro_cpu = HPTS_CPU_NONE;
2314 
2315 	callout_init_rw(&tp->t_callout, &inp->inp_lock,
2316 	    CALLOUT_TRYLOCK | CALLOUT_RETURNUNLOCKED);
2317 	for (int i = 0; i < TT_N; i++)
2318 		tp->t_timers[i] = SBT_MAX;
2319 
2320 	switch (V_tcp_do_rfc1323) {
2321 		case 0:
2322 			break;
2323 		default:
2324 		case 1:
2325 			tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
2326 			break;
2327 		case 2:
2328 			tp->t_flags = TF_REQ_SCALE;
2329 			break;
2330 		case 3:
2331 			tp->t_flags = TF_REQ_TSTMP;
2332 			break;
2333 	}
2334 	if (V_tcp_do_sack)
2335 		tp->t_flags |= TF_SACK_PERMIT;
2336 	TAILQ_INIT(&tp->snd_holes);
2337 
2338 	/*
2339 	 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
2340 	 * rtt estimate.  Set rttvar so that srtt + 4 * rttvar gives
2341 	 * reasonable initial retransmit time.
2342 	 */
2343 	tp->t_srtt = TCPTV_SRTTBASE;
2344 	tp->t_rttvar = ((tcp_rexmit_initial - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
2345 	tp->t_rttmin = tcp_rexmit_min;
2346 	tp->t_rxtcur = tcp_rexmit_initial;
2347 	tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
2348 	tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
2349 	tp->t_rcvtime = ticks;
2350 	/* We always start with ticks granularity */
2351 	tp->t_tmr_granularity = TCP_TMR_GRANULARITY_TICKS;
2352 	/*
2353 	 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
2354 	 * because the socket may be bound to an IPv6 wildcard address,
2355 	 * which may match an IPv4-mapped IPv6 address.
2356 	 */
2357 	inp->inp_ip_ttl = V_ip_defttl;
2358 #ifdef TCP_BLACKBOX
2359 	/* Initialize the per-TCPCB log data. */
2360 	tcp_log_tcpcbinit(tp);
2361 #endif
2362 	tp->t_pacing_rate = -1;
2363 	if (tp->t_fb->tfb_tcp_fb_init) {
2364 		if ((*tp->t_fb->tfb_tcp_fb_init)(tp, &tp->t_fb_ptr)) {
2365 			if (CC_ALGO(tp)->cb_destroy != NULL)
2366 				CC_ALGO(tp)->cb_destroy(&tp->t_ccv);
2367 			CC_DATA(tp) = NULL;
2368 			cc_detach(tp);
2369 #ifdef TCP_HHOOK
2370 			khelp_destroy_osd(&tp->t_osd);
2371 #endif
2372 			refcount_release(&tp->t_fb->tfb_refcnt);
2373 			return (NULL);
2374 		}
2375 	}
2376 #ifdef STATS
2377 	if (V_tcp_perconn_stats_enable == 1)
2378 		tp->t_stats = stats_blob_alloc(V_tcp_perconn_stats_dflt_tpl, 0);
2379 #endif
2380 	if (V_tcp_do_lrd)
2381 		tp->t_flags |= TF_LRD;
2382 
2383 	return (tp);
2384 }
2385 
2386 /*
2387  * Drop a TCP connection, reporting
2388  * the specified error.  If connection is synchronized,
2389  * then send a RST to peer.
2390  */
2391 struct tcpcb *
2392 tcp_drop(struct tcpcb *tp, int errno)
2393 {
2394 	struct socket *so = tptosocket(tp);
2395 
2396 	NET_EPOCH_ASSERT();
2397 	INP_WLOCK_ASSERT(tptoinpcb(tp));
2398 
2399 	if (TCPS_HAVERCVDSYN(tp->t_state)) {
2400 		tcp_state_change(tp, TCPS_CLOSED);
2401 		/* Don't use tcp_output() here due to possible recursion. */
2402 		(void)tcp_output_nodrop(tp);
2403 		TCPSTAT_INC(tcps_drops);
2404 	} else
2405 		TCPSTAT_INC(tcps_conndrops);
2406 	if (errno == ETIMEDOUT && tp->t_softerror)
2407 		errno = tp->t_softerror;
2408 	so->so_error = errno;
2409 	return (tcp_close(tp));
2410 }
2411 
2412 void
2413 tcp_discardcb(struct tcpcb *tp)
2414 {
2415 	struct inpcb *inp = tptoinpcb(tp);
2416 	struct socket *so = tptosocket(tp);
2417 	struct mbuf *m;
2418 #ifdef INET6
2419 	bool isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
2420 #endif
2421 
2422 	INP_WLOCK_ASSERT(inp);
2423 	MPASS(!callout_active(&tp->t_callout));
2424 	MPASS(TAILQ_EMPTY(&tp->snd_holes));
2425 
2426 	/* free the reassembly queue, if any */
2427 	tcp_reass_flush(tp);
2428 
2429 #ifdef TCP_OFFLOAD
2430 	/* Disconnect offload device, if any. */
2431 	if (tp->t_flags & TF_TOE)
2432 		tcp_offload_detach(tp);
2433 #endif
2434 
2435 	/* Allow the CC algorithm to clean up after itself. */
2436 	if (CC_ALGO(tp)->cb_destroy != NULL)
2437 		CC_ALGO(tp)->cb_destroy(&tp->t_ccv);
2438 	CC_DATA(tp) = NULL;
2439 	/* Detach from the CC algorithm */
2440 	cc_detach(tp);
2441 
2442 #ifdef TCP_HHOOK
2443 	khelp_destroy_osd(&tp->t_osd);
2444 #endif
2445 #ifdef STATS
2446 	stats_blob_destroy(tp->t_stats);
2447 #endif
2448 
2449 	CC_ALGO(tp) = NULL;
2450 	if ((m = STAILQ_FIRST(&tp->t_inqueue)) != NULL) {
2451 		struct mbuf *prev;
2452 
2453 		STAILQ_INIT(&tp->t_inqueue);
2454 		STAILQ_FOREACH_FROM_SAFE(m, &tp->t_inqueue, m_stailqpkt, prev)
2455 			m_freem(m);
2456 	}
2457 	TCPSTATES_DEC(tp->t_state);
2458 
2459 	if (tp->t_fb->tfb_tcp_fb_fini)
2460 		(*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
2461 	MPASS(!tcp_in_hpts(tp));
2462 #ifdef TCP_BLACKBOX
2463 	tcp_log_tcpcbfini(tp);
2464 #endif
2465 
2466 	/*
2467 	 * If we got enough samples through the srtt filter,
2468 	 * save the rtt and rttvar in the routing entry.
2469 	 * 'Enough' is arbitrarily defined as 4 rtt samples.
2470 	 * 4 samples is enough for the srtt filter to converge
2471 	 * to within enough % of the correct value; fewer samples
2472 	 * and we could save a bogus rtt. The danger is not high
2473 	 * as tcp quickly recovers from everything.
2474 	 * XXX: Works very well but needs some more statistics!
2475 	 *
2476 	 * XXXRRS: Updating must be after the stack fini() since
2477 	 * that may be converting some internal representation of
2478 	 * say srtt etc into the general one used by other stacks.
2479 	 */
2480 	if (tp->t_rttupdated >= 4) {
2481 		struct hc_metrics_lite metrics;
2482 		uint32_t ssthresh;
2483 
2484 		bzero(&metrics, sizeof(metrics));
2485 		/*
2486 		 * Update the ssthresh always when the conditions below
2487 		 * are satisfied. This gives us better new start value
2488 		 * for the congestion avoidance for new connections.
2489 		 * ssthresh is only set if packet loss occurred on a session.
2490 		 */
2491 		ssthresh = tp->snd_ssthresh;
2492 		if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) {
2493 			/*
2494 			 * convert the limit from user data bytes to
2495 			 * packets then to packet data bytes.
2496 			 */
2497 			ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg;
2498 			if (ssthresh < 2)
2499 				ssthresh = 2;
2500 			ssthresh *= (tp->t_maxseg +
2501 #ifdef INET6
2502 			    (isipv6 ? sizeof (struct ip6_hdr) +
2503 			    sizeof (struct tcphdr) :
2504 #endif
2505 			    sizeof (struct tcpiphdr)
2506 #ifdef INET6
2507 			    )
2508 #endif
2509 			    );
2510 		} else
2511 			ssthresh = 0;
2512 		metrics.hc_ssthresh = ssthresh;
2513 
2514 		metrics.hc_rtt = tp->t_srtt;
2515 		metrics.hc_rttvar = tp->t_rttvar;
2516 		metrics.hc_cwnd = tp->snd_cwnd;
2517 		metrics.hc_sendpipe = 0;
2518 		metrics.hc_recvpipe = 0;
2519 
2520 		tcp_hc_update(&inp->inp_inc, &metrics);
2521 	}
2522 
2523 	refcount_release(&tp->t_fb->tfb_refcnt);
2524 }
2525 
2526 /*
2527  * Attempt to close a TCP control block, marking it as dropped, and freeing
2528  * the socket if we hold the only reference.
2529  */
2530 struct tcpcb *
2531 tcp_close(struct tcpcb *tp)
2532 {
2533 	struct inpcb *inp = tptoinpcb(tp);
2534 	struct socket *so = tptosocket(tp);
2535 
2536 	INP_WLOCK_ASSERT(inp);
2537 
2538 #ifdef TCP_OFFLOAD
2539 	if (tp->t_state == TCPS_LISTEN)
2540 		tcp_offload_listen_stop(tp);
2541 #endif
2542 	/*
2543 	 * This releases the TFO pending counter resource for TFO listen
2544 	 * sockets as well as passively-created TFO sockets that transition
2545 	 * from SYN_RECEIVED to CLOSED.
2546 	 */
2547 	if (tp->t_tfo_pending) {
2548 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
2549 		tp->t_tfo_pending = NULL;
2550 	}
2551 	tcp_timer_stop(tp);
2552 	if (tp->t_fb->tfb_tcp_timer_stop_all != NULL)
2553 		tp->t_fb->tfb_tcp_timer_stop_all(tp);
2554 #if defined(INET) && defined(INET6)
2555 	if ((inp->inp_vflag & INP_IPV6) != 0)
2556 		in6_pcbdisconnect(inp);
2557 	else
2558 		in_pcbdisconnect(inp);
2559 #elif defined(INET6)
2560 	in6_pcbdisconnect(inp);
2561 #else
2562 	in_pcbdisconnect(inp);
2563 #endif
2564 	TCPSTAT_INC(tcps_closed);
2565 	if (tp->t_state != TCPS_CLOSED)
2566 		tcp_state_change(tp, TCPS_CLOSED);
2567 	tp->t_flags |= TF_DISCONNECTED;
2568 	KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
2569 	tcp_free_sackholes(tp);
2570 	soisdisconnected(so);
2571 	if (inp->inp_flags & INP_SOCKREF) {
2572 		inp->inp_flags &= ~INP_SOCKREF;
2573 		INP_WUNLOCK(inp);
2574 		sorele(so);
2575 		return (NULL);
2576 	}
2577 	return (tp);
2578 }
2579 
2580 /*
2581  * Notify a tcp user of an asynchronous error;
2582  * store error as soft error, but wake up user
2583  * (for now, won't do anything until can select for soft error).
2584  *
2585  * Do not wake up user since there currently is no mechanism for
2586  * reporting soft errors (yet - a kqueue filter may be added).
2587  */
2588 static struct inpcb *
2589 tcp_notify(struct inpcb *inp, int error)
2590 {
2591 	struct tcpcb *tp;
2592 
2593 	INP_WLOCK_ASSERT(inp);
2594 
2595 	tp = intotcpcb(inp);
2596 	KASSERT(tp != NULL, ("tcp_notify: tp == NULL"));
2597 
2598 	/*
2599 	 * Ignore some errors if we are hooked up.
2600 	 * If connection hasn't completed, has retransmitted several times,
2601 	 * and receives a second error, give up now.  This is better
2602 	 * than waiting a long time to establish a connection that
2603 	 * can never complete.
2604 	 */
2605 	if (tp->t_state == TCPS_ESTABLISHED &&
2606 	    (error == EHOSTUNREACH || error == ENETUNREACH ||
2607 	     error == EHOSTDOWN)) {
2608 		if (inp->inp_route.ro_nh) {
2609 			NH_FREE(inp->inp_route.ro_nh);
2610 			inp->inp_route.ro_nh = (struct nhop_object *)NULL;
2611 		}
2612 		return (inp);
2613 	} else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
2614 	    tp->t_softerror) {
2615 		tp = tcp_drop(tp, error);
2616 		if (tp != NULL)
2617 			return (inp);
2618 		else
2619 			return (NULL);
2620 	} else {
2621 		tp->t_softerror = error;
2622 		return (inp);
2623 	}
2624 #if 0
2625 	wakeup( &so->so_timeo);
2626 	sorwakeup(so);
2627 	sowwakeup(so);
2628 #endif
2629 }
2630 
2631 static int
2632 tcp_pcblist(SYSCTL_HANDLER_ARGS)
2633 {
2634 	struct inpcb_iterator inpi = INP_ALL_ITERATOR(&V_tcbinfo,
2635 	    INPLOOKUP_RLOCKPCB);
2636 	struct xinpgen xig;
2637 	struct inpcb *inp;
2638 	int error;
2639 
2640 	if (req->newptr != NULL)
2641 		return (EPERM);
2642 
2643 	if (req->oldptr == NULL) {
2644 		int n;
2645 
2646 		n = V_tcbinfo.ipi_count +
2647 		    counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
2648 		n += imax(n / 8, 10);
2649 		req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
2650 		return (0);
2651 	}
2652 
2653 	if ((error = sysctl_wire_old_buffer(req, 0)) != 0)
2654 		return (error);
2655 
2656 	bzero(&xig, sizeof(xig));
2657 	xig.xig_len = sizeof xig;
2658 	xig.xig_count = V_tcbinfo.ipi_count +
2659 	    counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
2660 	xig.xig_gen = V_tcbinfo.ipi_gencnt;
2661 	xig.xig_sogen = so_gencnt;
2662 	error = SYSCTL_OUT(req, &xig, sizeof xig);
2663 	if (error)
2664 		return (error);
2665 
2666 	error = syncache_pcblist(req);
2667 	if (error)
2668 		return (error);
2669 
2670 	while ((inp = inp_next(&inpi)) != NULL) {
2671 		if (inp->inp_gencnt <= xig.xig_gen &&
2672 		    cr_canseeinpcb(req->td->td_ucred, inp) == 0) {
2673 			struct xtcpcb xt;
2674 
2675 			tcp_inptoxtp(inp, &xt);
2676 			error = SYSCTL_OUT(req, &xt, sizeof xt);
2677 			if (error) {
2678 				INP_RUNLOCK(inp);
2679 				break;
2680 			} else
2681 				continue;
2682 		}
2683 	}
2684 
2685 	if (!error) {
2686 		/*
2687 		 * Give the user an updated idea of our state.
2688 		 * If the generation differs from what we told
2689 		 * her before, she knows that something happened
2690 		 * while we were processing this request, and it
2691 		 * might be necessary to retry.
2692 		 */
2693 		xig.xig_gen = V_tcbinfo.ipi_gencnt;
2694 		xig.xig_sogen = so_gencnt;
2695 		xig.xig_count = V_tcbinfo.ipi_count +
2696 		    counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
2697 		error = SYSCTL_OUT(req, &xig, sizeof xig);
2698 	}
2699 
2700 	return (error);
2701 }
2702 
2703 SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist,
2704     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_NEEDGIANT,
2705     NULL, 0, tcp_pcblist, "S,xtcpcb",
2706     "List of active TCP connections");
2707 
2708 #define SND_TAG_STATUS_MAXLEN	128
2709 
2710 #ifdef KERN_TLS
2711 
2712 static struct sx ktlslist_lock;
2713 SX_SYSINIT(ktlslistlock, &ktlslist_lock, "ktlslist");
2714 static uint64_t ktls_glob_gen = 1;
2715 
2716 static int
2717 tcp_ktlslist_locked(SYSCTL_HANDLER_ARGS, bool export_keys)
2718 {
2719 	struct xinpgen xig;
2720 	struct inpcb *inp;
2721 	struct socket *so;
2722 	struct ktls_session *ksr, *kss;
2723 	char *buf;
2724 	struct xktls_session *xktls;
2725 	uint64_t ipi_gencnt;
2726 	size_t buflen, len, sz;
2727 	u_int cnt;
2728 	int error;
2729 	bool ek, p;
2730 
2731 	sx_assert(&ktlslist_lock, SA_XLOCKED);
2732 	if (req->newptr != NULL)
2733 		return (EPERM);
2734 
2735 	len = 0;
2736 	cnt = 0;
2737 	ipi_gencnt = V_tcbinfo.ipi_gencnt;
2738 	bzero(&xig, sizeof(xig));
2739 	xig.xig_len = sizeof(xig);
2740 	xig.xig_gen = ktls_glob_gen++;
2741 	xig.xig_sogen = so_gencnt;
2742 
2743 	struct inpcb_iterator inpi = INP_ALL_ITERATOR(&V_tcbinfo,
2744 	    INPLOOKUP_RLOCKPCB);
2745 	while ((inp = inp_next(&inpi)) != NULL) {
2746 		if (inp->inp_gencnt > ipi_gencnt ||
2747 		    cr_canseeinpcb(req->td->td_ucred, inp) != 0)
2748 			continue;
2749 
2750 		so = inp->inp_socket;
2751 		if (so != NULL && so->so_gencnt <= xig.xig_sogen) {
2752 			p = false;
2753 			ek = export_keys && cr_canexport_ktlskeys(
2754 			    req->td, inp);
2755 			ksr = so->so_rcv.sb_tls_info;
2756 			if (ksr != NULL) {
2757 				ksr->gen = xig.xig_gen;
2758 				p = true;
2759 				if (ek) {
2760 					sz = SIZE_T_MAX;
2761 					ktls_session_copy_keys(ksr,
2762 					    NULL, &sz);
2763 					len += sz;
2764 				}
2765 				if (ksr->snd_tag != NULL &&
2766 				    ksr->snd_tag->sw->snd_tag_status_str !=
2767 				    NULL) {
2768 					sz = SND_TAG_STATUS_MAXLEN;
2769 					in_pcbref(inp);
2770 					INP_RUNLOCK(inp);
2771 					error = ksr->snd_tag->sw->
2772 					    snd_tag_status_str(
2773 					    ksr->snd_tag, NULL, &sz);
2774 					if (in_pcbrele_rlock(inp))
2775 						return (EDEADLK);
2776 					if (error == 0)
2777 						len += sz;
2778 				}
2779 			}
2780 			kss = so->so_snd.sb_tls_info;
2781 			if (kss != NULL) {
2782 				kss->gen = xig.xig_gen;
2783 				p = true;
2784 				if (ek) {
2785 					sz = SIZE_T_MAX;
2786 					ktls_session_copy_keys(kss,
2787 					    NULL, &sz);
2788 					len += sz;
2789 				}
2790 				if (kss->snd_tag != NULL &&
2791 				    kss->snd_tag->sw->snd_tag_status_str !=
2792 				    NULL) {
2793 					sz = SND_TAG_STATUS_MAXLEN;
2794 					in_pcbref(inp);
2795 					INP_RUNLOCK(inp);
2796 					error = kss->snd_tag->sw->
2797 					    snd_tag_status_str(
2798 					    kss->snd_tag, NULL, &sz);
2799 					if (in_pcbrele_rlock(inp))
2800 						return (EDEADLK);
2801 					if (error == 0)
2802 						len += sz;
2803 				}
2804 			}
2805 			if (p) {
2806 				len += sizeof(*xktls);
2807 				len = roundup2(len, __alignof(struct
2808 				    xktls_session));
2809 			}
2810 		}
2811 	}
2812 	if (req->oldptr == NULL) {
2813 		len += 2 * sizeof(xig);
2814 		len += 3 * len / 4;
2815 		req->oldidx = len;
2816 		return (0);
2817 	}
2818 
2819 	if ((error = sysctl_wire_old_buffer(req, 0)) != 0)
2820 		return (error);
2821 
2822 	error = SYSCTL_OUT(req, &xig, sizeof xig);
2823 	if (error != 0)
2824 		return (error);
2825 
2826 	buflen = roundup2(sizeof(*xktls) + 2 * TLS_MAX_PARAM_SIZE +
2827 	    2 * SND_TAG_STATUS_MAXLEN, __alignof(struct xktls_session));
2828 	buf = malloc(buflen, M_TEMP, M_WAITOK | M_ZERO);
2829 	struct inpcb_iterator inpi1 = INP_ALL_ITERATOR(&V_tcbinfo,
2830 	    INPLOOKUP_RLOCKPCB);
2831 	while ((inp = inp_next(&inpi1)) != NULL) {
2832 		if (inp->inp_gencnt > ipi_gencnt ||
2833 		    cr_canseeinpcb(req->td->td_ucred, inp) != 0)
2834 			continue;
2835 
2836 		so = inp->inp_socket;
2837 		if (so == NULL)
2838 			continue;
2839 
2840 		p = false;
2841 		ek = export_keys && cr_canexport_ktlskeys(req->td, inp);
2842 		ksr = so->so_rcv.sb_tls_info;
2843 		kss = so->so_snd.sb_tls_info;
2844 		xktls = (struct xktls_session *)buf;
2845 		if (ksr != NULL && ksr->gen == xig.xig_gen) {
2846 			p = true;
2847 			ktls_session_to_xktls_onedir(ksr, ek, &xktls->rcv);
2848 		}
2849 		if (kss != NULL && kss->gen == xig.xig_gen) {
2850 			p = true;
2851 			ktls_session_to_xktls_onedir(kss, ek, &xktls->snd);
2852 		}
2853 		if (!p)
2854 			continue;
2855 
2856 		xktls->inp_gencnt = inp->inp_gencnt;
2857 		xktls->so_pcb = (kvaddr_t)inp;
2858 		memcpy(&xktls->coninf, &inp->inp_inc, sizeof(xktls->coninf));
2859 		len = sizeof(*xktls);
2860 		if (ksr != NULL && ksr->gen == xig.xig_gen) {
2861 			if (ek) {
2862 				sz = buflen - len;
2863 				ktls_session_copy_keys(ksr, buf + len, &sz);
2864 				len += sz;
2865 			} else {
2866 				xktls->rcv.cipher_key_len = 0;
2867 				xktls->rcv.auth_key_len = 0;
2868 			}
2869 			if (ksr->snd_tag != NULL &&
2870 			    ksr->snd_tag->sw->snd_tag_status_str != NULL) {
2871 				sz = SND_TAG_STATUS_MAXLEN;
2872 				in_pcbref(inp);
2873 				INP_RUNLOCK(inp);
2874 				error = ksr->snd_tag->sw->snd_tag_status_str(
2875 				    ksr->snd_tag, buf + len, &sz);
2876 				if (in_pcbrele_rlock(inp))
2877 					return (EDEADLK);
2878 				if (error == 0) {
2879 					xktls->rcv.drv_st_len = sz;
2880 					len += sz;
2881 				}
2882 			}
2883 		}
2884 		if (kss != NULL && kss->gen == xig.xig_gen) {
2885 			if (ek) {
2886 				sz = buflen - len;
2887 				ktls_session_copy_keys(kss, buf + len, &sz);
2888 				len += sz;
2889 			} else {
2890 				xktls->snd.cipher_key_len = 0;
2891 				xktls->snd.auth_key_len = 0;
2892 			}
2893 			if (kss->snd_tag != NULL &&
2894 			    kss->snd_tag->sw->snd_tag_status_str != NULL) {
2895 				sz = SND_TAG_STATUS_MAXLEN;
2896 				in_pcbref(inp);
2897 				INP_RUNLOCK(inp);
2898 				error = kss->snd_tag->sw->snd_tag_status_str(
2899 				    kss->snd_tag, buf + len, &sz);
2900 				if (in_pcbrele_rlock(inp))
2901 					return (EDEADLK);
2902 				if (error == 0) {
2903 					xktls->snd.drv_st_len = sz;
2904 					len += sz;
2905 				}
2906 			}
2907 		}
2908 		len = roundup2(len, __alignof(*xktls));
2909 		xktls->tsz = len;
2910 		xktls->fsz = sizeof(*xktls);
2911 
2912 		error = SYSCTL_OUT(req, xktls, len);
2913 		if (error != 0) {
2914 			INP_RUNLOCK(inp);
2915 			break;
2916 		}
2917 		cnt++;
2918 	}
2919 
2920 	if (error == 0) {
2921 		xig.xig_sogen = so_gencnt;
2922 		xig.xig_count = cnt;
2923 		error = SYSCTL_OUT(req, &xig, sizeof(xig));
2924 	}
2925 
2926 	zfree(buf, M_TEMP);
2927 	return (error);
2928 }
2929 
2930 static int
2931 tcp_ktlslist1(SYSCTL_HANDLER_ARGS, bool export_keys)
2932 {
2933 	int repeats, error;
2934 
2935 	for (repeats = 0; repeats < 100; repeats++) {
2936 		if (sx_xlock_sig(&ktlslist_lock))
2937 			return (EINTR);
2938 		error = tcp_ktlslist_locked(oidp, arg1, arg2, req,
2939 		    export_keys);
2940 		sx_xunlock(&ktlslist_lock);
2941 		if (error != EDEADLK)
2942 			break;
2943 		if (sig_intr() != 0) {
2944 			error = EINTR;
2945 			break;
2946 		}
2947 		req->oldidx = 0;
2948 	}
2949 	return (error);
2950 }
2951 
2952 static int
2953 tcp_ktlslist_nokeys(SYSCTL_HANDLER_ARGS)
2954 {
2955 	return (tcp_ktlslist1(oidp, arg1, arg2, req, false));
2956 }
2957 
2958 static int
2959 tcp_ktlslist_wkeys(SYSCTL_HANDLER_ARGS)
2960 {
2961 	return (tcp_ktlslist1(oidp, arg1, arg2, req, true));
2962 }
2963 
2964 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KTLSLIST, ktlslist,
2965     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
2966     NULL, 0, tcp_ktlslist_nokeys, "S,xktls_session",
2967     "List of active kTLS sessions for TCP connections");
2968 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KTLSLIST_WKEYS, ktlslist_wkeys,
2969     CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
2970     NULL, 0, tcp_ktlslist_wkeys, "S,xktls_session",
2971     "List of active kTLS sessions for TCP connections with keys");
2972 #endif /* KERN_TLS */
2973 
2974 #ifdef INET
2975 static int
2976 tcp_getcred(SYSCTL_HANDLER_ARGS)
2977 {
2978 	struct xucred xuc;
2979 	struct sockaddr_in addrs[2];
2980 	struct epoch_tracker et;
2981 	struct inpcb *inp;
2982 	int error;
2983 
2984 	if (req->newptr == NULL)
2985 		return (EINVAL);
2986 	error = priv_check(req->td, PRIV_NETINET_GETCRED);
2987 	if (error)
2988 		return (error);
2989 	error = SYSCTL_IN(req, addrs, sizeof(addrs));
2990 	if (error)
2991 		return (error);
2992 	NET_EPOCH_ENTER(et);
2993 	inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
2994 	    addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL);
2995 	NET_EPOCH_EXIT(et);
2996 	if (inp != NULL) {
2997 		if (error == 0)
2998 			error = cr_canseeinpcb(req->td->td_ucred, inp);
2999 		if (error == 0)
3000 			cru2x(inp->inp_cred, &xuc);
3001 		INP_RUNLOCK(inp);
3002 	} else
3003 		error = ENOENT;
3004 	if (error == 0)
3005 		error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
3006 	return (error);
3007 }
3008 
3009 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
3010     CTLTYPE_OPAQUE | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_NEEDGIANT,
3011     0, 0, tcp_getcred, "S,xucred",
3012     "Get the xucred of a TCP connection");
3013 #endif /* INET */
3014 
3015 #ifdef INET6
3016 static int
3017 tcp6_getcred(SYSCTL_HANDLER_ARGS)
3018 {
3019 	struct epoch_tracker et;
3020 	struct xucred xuc;
3021 	struct sockaddr_in6 addrs[2];
3022 	struct inpcb *inp;
3023 	int error;
3024 #ifdef INET
3025 	int mapped = 0;
3026 #endif
3027 
3028 	if (req->newptr == NULL)
3029 		return (EINVAL);
3030 	error = priv_check(req->td, PRIV_NETINET_GETCRED);
3031 	if (error)
3032 		return (error);
3033 	error = SYSCTL_IN(req, addrs, sizeof(addrs));
3034 	if (error)
3035 		return (error);
3036 	if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
3037 	    (error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
3038 		return (error);
3039 	}
3040 	if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
3041 #ifdef INET
3042 		if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
3043 			mapped = 1;
3044 		else
3045 #endif
3046 			return (EINVAL);
3047 	}
3048 
3049 	NET_EPOCH_ENTER(et);
3050 #ifdef INET
3051 	if (mapped == 1)
3052 		inp = in_pcblookup(&V_tcbinfo,
3053 			*(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
3054 			addrs[1].sin6_port,
3055 			*(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
3056 			addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL);
3057 	else
3058 #endif
3059 		inp = in6_pcblookup(&V_tcbinfo,
3060 			&addrs[1].sin6_addr, addrs[1].sin6_port,
3061 			&addrs[0].sin6_addr, addrs[0].sin6_port,
3062 			INPLOOKUP_RLOCKPCB, NULL);
3063 	NET_EPOCH_EXIT(et);
3064 	if (inp != NULL) {
3065 		if (error == 0)
3066 			error = cr_canseeinpcb(req->td->td_ucred, inp);
3067 		if (error == 0)
3068 			cru2x(inp->inp_cred, &xuc);
3069 		INP_RUNLOCK(inp);
3070 	} else
3071 		error = ENOENT;
3072 	if (error == 0)
3073 		error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
3074 	return (error);
3075 }
3076 
3077 SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
3078     CTLTYPE_OPAQUE | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_NEEDGIANT,
3079     0, 0, tcp6_getcred, "S,xucred",
3080     "Get the xucred of a TCP6 connection");
3081 #endif /* INET6 */
3082 
3083 #ifdef INET
3084 /* Path MTU to try next when a fragmentation-needed message is received. */
3085 static inline int
3086 tcp_next_pmtu(const struct icmp *icp, const struct ip *ip)
3087 {
3088 	int mtu = ntohs(icp->icmp_nextmtu);
3089 
3090 	/* If no alternative MTU was proposed, try the next smaller one. */
3091 	if (!mtu)
3092 		mtu = ip_next_mtu(ntohs(ip->ip_len), 1);
3093 	if (mtu < V_tcp_minmss + sizeof(struct tcpiphdr))
3094 		mtu = V_tcp_minmss + sizeof(struct tcpiphdr);
3095 
3096 	return (mtu);
3097 }
3098 
3099 static void
3100 tcp_ctlinput_with_port(struct icmp *icp, uint16_t port)
3101 {
3102 	struct ip *ip;
3103 	struct tcphdr *th;
3104 	struct inpcb *inp;
3105 	struct tcpcb *tp;
3106 	struct inpcb *(*notify)(struct inpcb *, int);
3107 	struct in_conninfo inc;
3108 	tcp_seq icmp_tcp_seq;
3109 	int errno, mtu;
3110 
3111 	errno = icmp_errmap(icp);
3112 	switch (errno) {
3113 	case 0:
3114 		return;
3115 	case EMSGSIZE:
3116 		notify = tcp_mtudisc_notify;
3117 		break;
3118 	case ECONNREFUSED:
3119 		if (V_icmp_may_rst)
3120 			notify = tcp_drop_syn_sent;
3121 		else
3122 			notify = tcp_notify;
3123 		break;
3124 	case EHOSTUNREACH:
3125 		if (V_icmp_may_rst && icp->icmp_type == ICMP_TIMXCEED)
3126 			notify = tcp_drop_syn_sent;
3127 		else
3128 			notify = tcp_notify;
3129 		break;
3130 	default:
3131 		notify = tcp_notify;
3132 	}
3133 
3134 	ip = &icp->icmp_ip;
3135 	th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
3136 	icmp_tcp_seq = th->th_seq;
3137 	inp = in_pcblookup(&V_tcbinfo, ip->ip_dst, th->th_dport, ip->ip_src,
3138 	    th->th_sport, INPLOOKUP_WLOCKPCB, NULL);
3139 	if (inp != NULL)  {
3140 		tp = intotcpcb(inp);
3141 #ifdef TCP_OFFLOAD
3142 		if (tp->t_flags & TF_TOE && errno == EMSGSIZE) {
3143 			/*
3144 			 * MTU discovery for offloaded connections.  Let
3145 			 * the TOE driver verify seq# and process it.
3146 			 */
3147 			mtu = tcp_next_pmtu(icp, ip);
3148 			tcp_offload_pmtu_update(tp, icmp_tcp_seq, mtu);
3149 			goto out;
3150 		}
3151 #endif
3152 		if (tp->t_port != port)
3153 			goto out;
3154 		if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
3155 		    SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
3156 			if (errno == EMSGSIZE) {
3157 				/*
3158 				 * MTU discovery: we got a needfrag and
3159 				 * will potentially try a lower MTU.
3160 				 */
3161 				mtu = tcp_next_pmtu(icp, ip);
3162 
3163 				/*
3164 				 * Only process the offered MTU if it
3165 				 * is smaller than the current one.
3166 				 */
3167 				if (mtu < tp->t_maxseg +
3168 				    sizeof(struct tcpiphdr)) {
3169 					bzero(&inc, sizeof(inc));
3170 					inc.inc_faddr = ip->ip_dst;
3171 					inc.inc_fibnum =
3172 					    inp->inp_inc.inc_fibnum;
3173 					tcp_hc_updatemtu(&inc, mtu);
3174 					inp = tcp_mtudisc(inp, mtu);
3175 				}
3176 			} else
3177 				inp = (*notify)(inp, errno);
3178 		}
3179 	} else {
3180 		bzero(&inc, sizeof(inc));
3181 		inc.inc_fport = th->th_dport;
3182 		inc.inc_lport = th->th_sport;
3183 		inc.inc_faddr = ip->ip_dst;
3184 		inc.inc_laddr = ip->ip_src;
3185 		syncache_unreach(&inc, icmp_tcp_seq, port);
3186 	}
3187 out:
3188 	if (inp != NULL)
3189 		INP_WUNLOCK(inp);
3190 }
3191 
3192 static void
3193 tcp_ctlinput(struct icmp *icmp)
3194 {
3195 	tcp_ctlinput_with_port(icmp, htons(0));
3196 }
3197 
3198 static void
3199 tcp_ctlinput_viaudp(udp_tun_icmp_param_t param)
3200 {
3201 	/* Its a tunneled TCP over UDP icmp */
3202 	struct icmp *icmp = param.icmp;
3203 	struct ip *outer_ip, *inner_ip;
3204 	struct udphdr *udp;
3205 	struct tcphdr *th, ttemp;
3206 	int i_hlen, o_len;
3207 	uint16_t port;
3208 
3209 	outer_ip = (struct ip *)((caddr_t)icmp - sizeof(struct ip));
3210 	inner_ip = &icmp->icmp_ip;
3211 	i_hlen = inner_ip->ip_hl << 2;
3212 	o_len = ntohs(outer_ip->ip_len);
3213 	if (o_len <
3214 	    (sizeof(struct ip) + 8 + i_hlen + sizeof(struct udphdr) + offsetof(struct tcphdr, th_ack))) {
3215 		/* Not enough data present */
3216 		return;
3217 	}
3218 	/* Ok lets strip out the inner udphdr header by copying up on top of it the tcp hdr */
3219 	udp = (struct udphdr *)(((caddr_t)inner_ip) + i_hlen);
3220 	if (ntohs(udp->uh_sport) != V_tcp_udp_tunneling_port) {
3221 		return;
3222 	}
3223 	port = udp->uh_dport;
3224 	th = (struct tcphdr *)(udp + 1);
3225 	memcpy(&ttemp, th, sizeof(struct tcphdr));
3226 	memcpy(udp, &ttemp, sizeof(struct tcphdr));
3227 	/* Now adjust down the size of the outer IP header */
3228 	o_len -= sizeof(struct udphdr);
3229 	outer_ip->ip_len = htons(o_len);
3230 	/* Now call in to the normal handling code */
3231 	tcp_ctlinput_with_port(icmp, port);
3232 }
3233 #endif /* INET */
3234 
3235 #ifdef INET6
3236 static inline int
3237 tcp6_next_pmtu(const struct icmp6_hdr *icmp6)
3238 {
3239 	int mtu = ntohl(icmp6->icmp6_mtu);
3240 
3241 	/*
3242 	 * If no alternative MTU was proposed, or the proposed MTU was too
3243 	 * small, set to the min.
3244 	 */
3245 	if (mtu < IPV6_MMTU)
3246 		mtu = IPV6_MMTU;
3247 	return (mtu);
3248 }
3249 
3250 static void
3251 tcp6_ctlinput_with_port(struct ip6ctlparam *ip6cp, uint16_t port)
3252 {
3253 	struct in6_addr *dst;
3254 	struct inpcb *(*notify)(struct inpcb *, int);
3255 	struct ip6_hdr *ip6;
3256 	struct mbuf *m;
3257 	struct inpcb *inp;
3258 	struct tcpcb *tp;
3259 	struct icmp6_hdr *icmp6;
3260 	struct in_conninfo inc;
3261 	struct tcp_ports {
3262 		uint16_t th_sport;
3263 		uint16_t th_dport;
3264 	} t_ports;
3265 	tcp_seq icmp_tcp_seq;
3266 	unsigned int mtu;
3267 	unsigned int off;
3268 	int errno;
3269 
3270 	icmp6 = ip6cp->ip6c_icmp6;
3271 	m = ip6cp->ip6c_m;
3272 	ip6 = ip6cp->ip6c_ip6;
3273 	off = ip6cp->ip6c_off;
3274 	dst = &ip6cp->ip6c_finaldst->sin6_addr;
3275 
3276 	errno = icmp6_errmap(icmp6);
3277 	switch (errno) {
3278 	case 0:
3279 		return;
3280 	case EMSGSIZE:
3281 		notify = tcp_mtudisc_notify;
3282 		break;
3283 	case ECONNREFUSED:
3284 		if (V_icmp_may_rst)
3285 			notify = tcp_drop_syn_sent;
3286 		else
3287 			notify = tcp_notify;
3288 		break;
3289 	case EHOSTUNREACH:
3290 		/*
3291 		 * There are only four ICMPs that may reset connection:
3292 		 * - administratively prohibited
3293 		 * - port unreachable
3294 		 * - time exceeded in transit
3295 		 * - unknown next header
3296 		 */
3297 		if (V_icmp_may_rst &&
3298 		    ((icmp6->icmp6_type == ICMP6_DST_UNREACH &&
3299 		     (icmp6->icmp6_code == ICMP6_DST_UNREACH_ADMIN ||
3300 		      icmp6->icmp6_code == ICMP6_DST_UNREACH_NOPORT)) ||
3301 		    (icmp6->icmp6_type == ICMP6_TIME_EXCEEDED &&
3302 		      icmp6->icmp6_code == ICMP6_TIME_EXCEED_TRANSIT) ||
3303 		    (icmp6->icmp6_type == ICMP6_PARAM_PROB &&
3304 		      icmp6->icmp6_code == ICMP6_PARAMPROB_NEXTHEADER)))
3305 			notify = tcp_drop_syn_sent;
3306 		else
3307 			notify = tcp_notify;
3308 		break;
3309 	default:
3310 		notify = tcp_notify;
3311 	}
3312 
3313 	/* Check if we can safely get the ports from the tcp hdr */
3314 	if (m == NULL ||
3315 	    (m->m_pkthdr.len <
3316 		(int32_t) (off + sizeof(struct tcp_ports)))) {
3317 		return;
3318 	}
3319 	bzero(&t_ports, sizeof(struct tcp_ports));
3320 	m_copydata(m, off, sizeof(struct tcp_ports), (caddr_t)&t_ports);
3321 	inp = in6_pcblookup(&V_tcbinfo, &ip6->ip6_dst, t_ports.th_dport,
3322 	    &ip6->ip6_src, t_ports.th_sport, INPLOOKUP_WLOCKPCB, NULL);
3323 	off += sizeof(struct tcp_ports);
3324 	if (m->m_pkthdr.len < (int32_t) (off + sizeof(tcp_seq))) {
3325 		goto out;
3326 	}
3327 	m_copydata(m, off, sizeof(tcp_seq), (caddr_t)&icmp_tcp_seq);
3328 	if (inp != NULL)  {
3329 		tp = intotcpcb(inp);
3330 #ifdef TCP_OFFLOAD
3331 		if (tp->t_flags & TF_TOE && errno == EMSGSIZE) {
3332 			/* MTU discovery for offloaded connections. */
3333 			mtu = tcp6_next_pmtu(icmp6);
3334 			tcp_offload_pmtu_update(tp, icmp_tcp_seq, mtu);
3335 			goto out;
3336 		}
3337 #endif
3338 		if (tp->t_port != port)
3339 			goto out;
3340 		if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
3341 		    SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
3342 			if (errno == EMSGSIZE) {
3343 				/*
3344 				 * MTU discovery:
3345 				 * If we got a needfrag set the MTU
3346 				 * in the route to the suggested new
3347 				 * value (if given) and then notify.
3348 				 */
3349 				mtu = tcp6_next_pmtu(icmp6);
3350 
3351 				bzero(&inc, sizeof(inc));
3352 				inc.inc_fibnum = M_GETFIB(m);
3353 				inc.inc_flags |= INC_ISIPV6;
3354 				inc.inc6_faddr = *dst;
3355 				if (in6_setscope(&inc.inc6_faddr,
3356 					m->m_pkthdr.rcvif, NULL))
3357 					goto out;
3358 				/*
3359 				 * Only process the offered MTU if it
3360 				 * is smaller than the current one.
3361 				 */
3362 				if (mtu < tp->t_maxseg +
3363 				    sizeof (struct tcphdr) +
3364 				    sizeof (struct ip6_hdr)) {
3365 					tcp_hc_updatemtu(&inc, mtu);
3366 					tcp_mtudisc(inp, mtu);
3367 					ICMP6STAT_INC(icp6s_pmtuchg);
3368 				}
3369 			} else
3370 				inp = (*notify)(inp, errno);
3371 		}
3372 	} else {
3373 		bzero(&inc, sizeof(inc));
3374 		inc.inc_fibnum = M_GETFIB(m);
3375 		inc.inc_flags |= INC_ISIPV6;
3376 		inc.inc_fport = t_ports.th_dport;
3377 		inc.inc_lport = t_ports.th_sport;
3378 		inc.inc6_faddr = *dst;
3379 		inc.inc6_laddr = ip6->ip6_src;
3380 		syncache_unreach(&inc, icmp_tcp_seq, port);
3381 	}
3382 out:
3383 	if (inp != NULL)
3384 		INP_WUNLOCK(inp);
3385 }
3386 
3387 static void
3388 tcp6_ctlinput(struct ip6ctlparam *ctl)
3389 {
3390 	tcp6_ctlinput_with_port(ctl, htons(0));
3391 }
3392 
3393 static void
3394 tcp6_ctlinput_viaudp(udp_tun_icmp_param_t param)
3395 {
3396 	struct ip6ctlparam *ip6cp = param.ip6cp;
3397 	struct mbuf *m;
3398 	struct udphdr *udp;
3399 	uint16_t port;
3400 
3401 	m = m_pulldown(ip6cp->ip6c_m, ip6cp->ip6c_off, sizeof(struct udphdr), NULL);
3402 	if (m == NULL) {
3403 		return;
3404 	}
3405 	udp = mtod(m, struct udphdr *);
3406 	if (ntohs(udp->uh_sport) != V_tcp_udp_tunneling_port) {
3407 		return;
3408 	}
3409 	port = udp->uh_dport;
3410 	m_adj(m, sizeof(struct udphdr));
3411 	if ((m->m_flags & M_PKTHDR) == 0) {
3412 		ip6cp->ip6c_m->m_pkthdr.len -= sizeof(struct udphdr);
3413 	}
3414 	/* Now call in to the normal handling code */
3415 	tcp6_ctlinput_with_port(ip6cp, port);
3416 }
3417 
3418 #endif /* INET6 */
3419 
3420 static uint32_t
3421 tcp_keyed_hash(struct in_conninfo *inc, u_char *key, u_int len)
3422 {
3423 	SIPHASH_CTX ctx;
3424 	uint32_t hash[2];
3425 
3426 	KASSERT(len >= SIPHASH_KEY_LENGTH,
3427 	    ("%s: keylen %u too short ", __func__, len));
3428 	SipHash24_Init(&ctx);
3429 	SipHash_SetKey(&ctx, (uint8_t *)key);
3430 	SipHash_Update(&ctx, &inc->inc_fport, sizeof(uint16_t));
3431 	SipHash_Update(&ctx, &inc->inc_lport, sizeof(uint16_t));
3432 	switch (inc->inc_flags & INC_ISIPV6) {
3433 #ifdef INET
3434 	case 0:
3435 		SipHash_Update(&ctx, &inc->inc_faddr, sizeof(struct in_addr));
3436 		SipHash_Update(&ctx, &inc->inc_laddr, sizeof(struct in_addr));
3437 		break;
3438 #endif
3439 #ifdef INET6
3440 	case INC_ISIPV6:
3441 		SipHash_Update(&ctx, &inc->inc6_faddr, sizeof(struct in6_addr));
3442 		SipHash_Update(&ctx, &inc->inc6_laddr, sizeof(struct in6_addr));
3443 		break;
3444 #endif
3445 	}
3446 	SipHash_Final((uint8_t *)hash, &ctx);
3447 
3448 	return (hash[0] ^ hash[1]);
3449 }
3450 
3451 uint32_t
3452 tcp_new_ts_offset(struct in_conninfo *inc)
3453 {
3454 	struct in_conninfo inc_store, *local_inc;
3455 
3456 	if (!V_tcp_ts_offset_per_conn) {
3457 		memcpy(&inc_store, inc, sizeof(struct in_conninfo));
3458 		inc_store.inc_lport = 0;
3459 		inc_store.inc_fport = 0;
3460 		local_inc = &inc_store;
3461 	} else {
3462 		local_inc = inc;
3463 	}
3464 	return (tcp_keyed_hash(local_inc, V_ts_offset_secret,
3465 	    sizeof(V_ts_offset_secret)));
3466 }
3467 
3468 /*
3469  * Following is where TCP initial sequence number generation occurs.
3470  *
3471  * There are two places where we must use initial sequence numbers:
3472  * 1.  In SYN-ACK packets.
3473  * 2.  In SYN packets.
3474  *
3475  * All ISNs for SYN-ACK packets are generated by the syncache.  See
3476  * tcp_syncache.c for details.
3477  *
3478  * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
3479  * depends on this property.  In addition, these ISNs should be
3480  * unguessable so as to prevent connection hijacking.  To satisfy
3481  * the requirements of this situation, the algorithm outlined in
3482  * RFC 1948 is used, with only small modifications.
3483  *
3484  * Implementation details:
3485  *
3486  * Time is based off the system timer, and is corrected so that it
3487  * increases by one megabyte per second.  This allows for proper
3488  * recycling on high speed LANs while still leaving over an hour
3489  * before rollover.
3490  *
3491  * As reading the *exact* system time is too expensive to be done
3492  * whenever setting up a TCP connection, we increment the time
3493  * offset in two ways.  First, a small random positive increment
3494  * is added to isn_offset for each connection that is set up.
3495  * Second, the function tcp_isn_tick fires once per clock tick
3496  * and increments isn_offset as necessary so that sequence numbers
3497  * are incremented at approximately ISN_BYTES_PER_SECOND.  The
3498  * random positive increments serve only to ensure that the same
3499  * exact sequence number is never sent out twice (as could otherwise
3500  * happen when a port is recycled in less than the system tick
3501  * interval.)
3502  *
3503  * net.inet.tcp.isn_reseed_interval controls the number of seconds
3504  * between seeding of isn_secret.  This is normally set to zero,
3505  * as reseeding should not be necessary.
3506  *
3507  * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
3508  * isn_offset_old, and isn_ctx is performed using the ISN lock.  In
3509  * general, this means holding an exclusive (write) lock.
3510  */
3511 
3512 #define ISN_BYTES_PER_SECOND 1048576
3513 #define ISN_STATIC_INCREMENT 4096
3514 #define ISN_RANDOM_INCREMENT (4096 - 1)
3515 #define ISN_SECRET_LENGTH    SIPHASH_KEY_LENGTH
3516 
3517 VNET_DEFINE_STATIC(u_char, isn_secret[ISN_SECRET_LENGTH]);
3518 VNET_DEFINE_STATIC(int, isn_last);
3519 VNET_DEFINE_STATIC(int, isn_last_reseed);
3520 VNET_DEFINE_STATIC(u_int32_t, isn_offset);
3521 VNET_DEFINE_STATIC(u_int32_t, isn_offset_old);
3522 
3523 #define	V_isn_secret			VNET(isn_secret)
3524 #define	V_isn_last			VNET(isn_last)
3525 #define	V_isn_last_reseed		VNET(isn_last_reseed)
3526 #define	V_isn_offset			VNET(isn_offset)
3527 #define	V_isn_offset_old		VNET(isn_offset_old)
3528 
3529 tcp_seq
3530 tcp_new_isn(struct in_conninfo *inc)
3531 {
3532 	tcp_seq new_isn;
3533 	u_int32_t projected_offset;
3534 
3535 	ISN_LOCK();
3536 	/* Seed if this is the first use, reseed if requested. */
3537 	if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) &&
3538 	     (((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz)
3539 		< (u_int)ticks))) {
3540 		arc4rand(&V_isn_secret, sizeof(V_isn_secret), 0);
3541 		V_isn_last_reseed = ticks;
3542 	}
3543 
3544 	/* Compute the hash and return the ISN. */
3545 	new_isn = (tcp_seq)tcp_keyed_hash(inc, V_isn_secret,
3546 	    sizeof(V_isn_secret));
3547 	V_isn_offset += ISN_STATIC_INCREMENT +
3548 		(arc4random() & ISN_RANDOM_INCREMENT);
3549 	if (ticks != V_isn_last) {
3550 		projected_offset = V_isn_offset_old +
3551 		    ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last);
3552 		if (SEQ_GT(projected_offset, V_isn_offset))
3553 			V_isn_offset = projected_offset;
3554 		V_isn_offset_old = V_isn_offset;
3555 		V_isn_last = ticks;
3556 	}
3557 	new_isn += V_isn_offset;
3558 	ISN_UNLOCK();
3559 	return (new_isn);
3560 }
3561 
3562 /*
3563  * When a specific ICMP unreachable message is received and the
3564  * connection state is SYN-SENT, drop the connection.  This behavior
3565  * is controlled by the icmp_may_rst sysctl.
3566  */
3567 static struct inpcb *
3568 tcp_drop_syn_sent(struct inpcb *inp, int errno)
3569 {
3570 	struct tcpcb *tp;
3571 
3572 	NET_EPOCH_ASSERT();
3573 	INP_WLOCK_ASSERT(inp);
3574 
3575 	tp = intotcpcb(inp);
3576 	if (tp->t_state != TCPS_SYN_SENT)
3577 		return (inp);
3578 
3579 	if (tp->t_flags & TF_FASTOPEN)
3580 		tcp_fastopen_disable_path(tp);
3581 
3582 	tp = tcp_drop(tp, errno);
3583 	if (tp != NULL)
3584 		return (inp);
3585 	else
3586 		return (NULL);
3587 }
3588 
3589 /*
3590  * When `need fragmentation' ICMP is received, update our idea of the MSS
3591  * based on the new value. Also nudge TCP to send something, since we
3592  * know the packet we just sent was dropped.
3593  * This duplicates some code in the tcp_mss() function in tcp_input.c.
3594  */
3595 static struct inpcb *
3596 tcp_mtudisc_notify(struct inpcb *inp, int error)
3597 {
3598 
3599 	return (tcp_mtudisc(inp, -1));
3600 }
3601 
3602 static struct inpcb *
3603 tcp_mtudisc(struct inpcb *inp, int mtuoffer)
3604 {
3605 	struct tcpcb *tp;
3606 	struct socket *so;
3607 
3608 	INP_WLOCK_ASSERT(inp);
3609 
3610 	tp = intotcpcb(inp);
3611 	KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
3612 
3613 	tcp_mss_update(tp, -1, mtuoffer, NULL, NULL);
3614 
3615 	so = inp->inp_socket;
3616 	SOCK_SENDBUF_LOCK(so);
3617 	/* If the mss is larger than the socket buffer, decrease the mss. */
3618 	if (so->so_snd.sb_hiwat < tp->t_maxseg) {
3619 		tp->t_maxseg = so->so_snd.sb_hiwat;
3620 		if (tp->t_maxseg < V_tcp_mssdflt) {
3621 			/*
3622 			 * The MSS is so small we should not process incoming
3623 			 * SACK's since we are subject to attack in such a
3624 			 * case.
3625 			 */
3626 			tp->t_flags2 |= TF2_PROC_SACK_PROHIBIT;
3627 		} else {
3628 			tp->t_flags2 &= ~TF2_PROC_SACK_PROHIBIT;
3629 		}
3630 	}
3631 	SOCK_SENDBUF_UNLOCK(so);
3632 
3633 	TCPSTAT_INC(tcps_mturesent);
3634 	tp->t_rtttime = 0;
3635 	tp->snd_nxt = tp->snd_una;
3636 	tcp_free_sackholes(tp);
3637 	tp->snd_recover = tp->snd_max;
3638 	if (tp->t_flags & TF_SACK_PERMIT)
3639 		EXIT_FASTRECOVERY(tp->t_flags);
3640 	if (tp->t_fb->tfb_tcp_mtu_chg != NULL) {
3641 		/*
3642 		 * Conceptually the snd_nxt setting
3643 		 * and freeing sack holes should
3644 		 * be done by the default stacks
3645 		 * own tfb_tcp_mtu_chg().
3646 		 */
3647 		tp->t_fb->tfb_tcp_mtu_chg(tp);
3648 	}
3649 	if (tcp_output(tp) < 0)
3650 		return (NULL);
3651 	else
3652 		return (inp);
3653 }
3654 
3655 #ifdef INET
3656 /*
3657  * Look-up the routing entry to the peer of this inpcb.  If no route
3658  * is found and it cannot be allocated, then return 0.  This routine
3659  * is called by TCP routines that access the rmx structure and by
3660  * tcp_mss_update to get the peer/interface MTU.
3661  */
3662 uint32_t
3663 tcp_maxmtu(struct in_conninfo *inc, struct tcp_ifcap *cap)
3664 {
3665 	struct nhop_object *nh;
3666 	struct ifnet *ifp;
3667 	uint32_t maxmtu = 0;
3668 
3669 	KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
3670 
3671 	if (inc->inc_faddr.s_addr != INADDR_ANY) {
3672 		nh = fib4_lookup(inc->inc_fibnum, inc->inc_faddr, 0, NHR_NONE, 0);
3673 		if (nh == NULL)
3674 			return (0);
3675 
3676 		ifp = nh->nh_ifp;
3677 		maxmtu = nh->nh_mtu;
3678 
3679 		/* Report additional interface capabilities. */
3680 		if (cap != NULL) {
3681 			if (ifp->if_capenable & IFCAP_TSO4 &&
3682 			    ifp->if_hwassist & CSUM_TSO) {
3683 				cap->ifcap |= CSUM_TSO;
3684 				cap->tsomax = ifp->if_hw_tsomax;
3685 				cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
3686 				cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
3687 				/* XXXKIB IFCAP2_IPSEC_OFFLOAD_TSO */
3688 				cap->ipsec_tso =  (ifp->if_capenable2 &
3689 				    IFCAP2_BIT(IFCAP2_IPSEC_OFFLOAD)) != 0;
3690 			}
3691 		}
3692 	}
3693 	return (maxmtu);
3694 }
3695 #endif /* INET */
3696 
3697 #ifdef INET6
3698 uint32_t
3699 tcp_maxmtu6(struct in_conninfo *inc, struct tcp_ifcap *cap)
3700 {
3701 	struct nhop_object *nh;
3702 	struct in6_addr dst6;
3703 	uint32_t scopeid;
3704 	struct ifnet *ifp;
3705 	uint32_t maxmtu = 0;
3706 
3707 	KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
3708 
3709 	if (inc->inc_flags & INC_IPV6MINMTU)
3710 		return (IPV6_MMTU);
3711 
3712 	if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
3713 		in6_splitscope(&inc->inc6_faddr, &dst6, &scopeid);
3714 		nh = fib6_lookup(inc->inc_fibnum, &dst6, scopeid, NHR_NONE, 0);
3715 		if (nh == NULL)
3716 			return (0);
3717 
3718 		ifp = nh->nh_ifp;
3719 		maxmtu = nh->nh_mtu;
3720 
3721 		/* Report additional interface capabilities. */
3722 		if (cap != NULL) {
3723 			if (ifp->if_capenable & IFCAP_TSO6 &&
3724 			    ifp->if_hwassist & CSUM_TSO) {
3725 				cap->ifcap |= CSUM_TSO;
3726 				cap->tsomax = ifp->if_hw_tsomax;
3727 				cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
3728 				cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
3729 				cap->ipsec_tso = false; /* XXXKIB */
3730 			}
3731 		}
3732 	}
3733 
3734 	return (maxmtu);
3735 }
3736 
3737 /*
3738  * Handle setsockopt(IPV6_USE_MIN_MTU) by a TCP stack.
3739  *
3740  * XXXGL: we are updating inpcb here with INC_IPV6MINMTU flag.
3741  * The right place to do that is ip6_setpktopt() that has just been
3742  * executed.  By the way it just filled ip6po_minmtu for us.
3743  */
3744 void
3745 tcp6_use_min_mtu(struct tcpcb *tp)
3746 {
3747 	struct inpcb *inp = tptoinpcb(tp);
3748 
3749 	INP_WLOCK_ASSERT(inp);
3750 	/*
3751 	 * In case of the IPV6_USE_MIN_MTU socket
3752 	 * option, the INC_IPV6MINMTU flag to announce
3753 	 * a corresponding MSS during the initial
3754 	 * handshake.  If the TCP connection is not in
3755 	 * the front states, just reduce the MSS being
3756 	 * used.  This avoids the sending of TCP
3757 	 * segments which will be fragmented at the
3758 	 * IPv6 layer.
3759 	 */
3760 	inp->inp_inc.inc_flags |= INC_IPV6MINMTU;
3761 	if ((tp->t_state >= TCPS_SYN_SENT) &&
3762 	    (inp->inp_inc.inc_flags & INC_ISIPV6)) {
3763 		struct ip6_pktopts *opt;
3764 
3765 		opt = inp->in6p_outputopts;
3766 		if (opt != NULL && opt->ip6po_minmtu == IP6PO_MINMTU_ALL &&
3767 		    tp->t_maxseg > TCP6_MSS) {
3768 			tp->t_maxseg = TCP6_MSS;
3769 			if (tp->t_maxseg < V_tcp_mssdflt) {
3770 				/*
3771 				 * The MSS is so small we should not process incoming
3772 				 * SACK's since we are subject to attack in such a
3773 				 * case.
3774 				 */
3775 				tp->t_flags2 |= TF2_PROC_SACK_PROHIBIT;
3776 			} else {
3777 				tp->t_flags2 &= ~TF2_PROC_SACK_PROHIBIT;
3778 			}
3779 		}
3780 	}
3781 }
3782 #endif /* INET6 */
3783 
3784 /*
3785  * Calculate effective SMSS per RFC5681 definition for a given TCP
3786  * connection at its current state, taking into account SACK and etc.
3787  */
3788 u_int
3789 tcp_maxseg(const struct tcpcb *tp)
3790 {
3791 	u_int optlen;
3792 
3793 	if (tp->t_flags & TF_NOOPT)
3794 		return (tp->t_maxseg);
3795 
3796 	/*
3797 	 * Here we have a simplified code from tcp_addoptions(),
3798 	 * without a proper loop, and having most of paddings hardcoded.
3799 	 * We might make mistakes with padding here in some edge cases,
3800 	 * but this is harmless, since result of tcp_maxseg() is used
3801 	 * only in cwnd and ssthresh estimations.
3802 	 */
3803 	if (TCPS_HAVEESTABLISHED(tp->t_state)) {
3804 		if (tp->t_flags & TF_RCVD_TSTMP)
3805 			optlen = TCPOLEN_TSTAMP_APPA;
3806 		else
3807 			optlen = 0;
3808 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
3809 		if (tp->t_flags & TF_SIGNATURE)
3810 			optlen += PADTCPOLEN(TCPOLEN_SIGNATURE);
3811 #endif
3812 		if ((tp->t_flags & TF_SACK_PERMIT) && tp->rcv_numsacks > 0) {
3813 			optlen += TCPOLEN_SACKHDR;
3814 			optlen += tp->rcv_numsacks * TCPOLEN_SACK;
3815 			optlen = PADTCPOLEN(optlen);
3816 		}
3817 	} else {
3818 		if (tp->t_flags & TF_REQ_TSTMP)
3819 			optlen = TCPOLEN_TSTAMP_APPA;
3820 		else
3821 			optlen = PADTCPOLEN(TCPOLEN_MAXSEG);
3822 		if (tp->t_flags & TF_REQ_SCALE)
3823 			optlen += PADTCPOLEN(TCPOLEN_WINDOW);
3824 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
3825 		if (tp->t_flags & TF_SIGNATURE)
3826 			optlen += PADTCPOLEN(TCPOLEN_SIGNATURE);
3827 #endif
3828 		if (tp->t_flags & TF_SACK_PERMIT)
3829 			optlen += PADTCPOLEN(TCPOLEN_SACK_PERMITTED);
3830 	}
3831 	optlen = min(optlen, TCP_MAXOLEN);
3832 	return (tp->t_maxseg - optlen);
3833 }
3834 
3835 
3836 u_int
3837 tcp_fixed_maxseg(const struct tcpcb *tp)
3838 {
3839 	int optlen;
3840 
3841 	if (tp->t_flags & TF_NOOPT)
3842 		return (tp->t_maxseg);
3843 
3844 	/*
3845 	 * Here we have a simplified code from tcp_addoptions(),
3846 	 * without a proper loop, and having most of paddings hardcoded.
3847 	 * We only consider fixed options that we would send every
3848 	 * time I.e. SACK is not considered. This is important
3849 	 * for cc modules to figure out what the modulo of the
3850 	 * cwnd should be.
3851 	 */
3852 	if (TCPS_HAVEESTABLISHED(tp->t_state)) {
3853 		if (tp->t_flags & TF_RCVD_TSTMP)
3854 			optlen = TCPOLEN_TSTAMP_APPA;
3855 		else
3856 			optlen = 0;
3857 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
3858 		if (tp->t_flags & TF_SIGNATURE)
3859 			optlen += PADTCPOLEN(TCPOLEN_SIGNATURE);
3860 #endif
3861 	} else {
3862 		if (tp->t_flags & TF_REQ_TSTMP)
3863 			optlen = TCPOLEN_TSTAMP_APPA;
3864 		else
3865 			optlen = PADTCPOLEN(TCPOLEN_MAXSEG);
3866 		if (tp->t_flags & TF_REQ_SCALE)
3867 			optlen += PADTCPOLEN(TCPOLEN_WINDOW);
3868 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
3869 		if (tp->t_flags & TF_SIGNATURE)
3870 			optlen += PADTCPOLEN(TCPOLEN_SIGNATURE);
3871 #endif
3872 		if (tp->t_flags & TF_SACK_PERMIT)
3873 			optlen += PADTCPOLEN(TCPOLEN_SACK_PERMITTED);
3874 	}
3875 	optlen = min(optlen, TCP_MAXOLEN);
3876 	return (tp->t_maxseg - optlen);
3877 }
3878 
3879 
3880 
3881 static int
3882 sysctl_drop(SYSCTL_HANDLER_ARGS)
3883 {
3884 	/* addrs[0] is a foreign socket, addrs[1] is a local one. */
3885 	struct sockaddr_storage addrs[2];
3886 	struct inpcb *inp;
3887 	struct tcpcb *tp;
3888 #ifdef INET
3889 	struct sockaddr_in *fin = NULL, *lin = NULL;
3890 #endif
3891 	struct epoch_tracker et;
3892 #ifdef INET6
3893 	struct sockaddr_in6 *fin6, *lin6;
3894 #endif
3895 	int error;
3896 
3897 	inp = NULL;
3898 #ifdef INET6
3899 	fin6 = lin6 = NULL;
3900 #endif
3901 	error = 0;
3902 
3903 	if (req->oldptr != NULL || req->oldlen != 0)
3904 		return (EINVAL);
3905 	if (req->newptr == NULL)
3906 		return (EPERM);
3907 	if (req->newlen < sizeof(addrs))
3908 		return (ENOMEM);
3909 	error = SYSCTL_IN(req, &addrs, sizeof(addrs));
3910 	if (error)
3911 		return (error);
3912 
3913 	switch (addrs[0].ss_family) {
3914 #ifdef INET6
3915 	case AF_INET6:
3916 		fin6 = (struct sockaddr_in6 *)&addrs[0];
3917 		lin6 = (struct sockaddr_in6 *)&addrs[1];
3918 		if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
3919 		    lin6->sin6_len != sizeof(struct sockaddr_in6))
3920 			return (EINVAL);
3921 		if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
3922 			if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
3923 				return (EINVAL);
3924 			in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
3925 			in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
3926 #ifdef INET
3927 			fin = (struct sockaddr_in *)&addrs[0];
3928 			lin = (struct sockaddr_in *)&addrs[1];
3929 #endif
3930 			break;
3931 		}
3932 		error = sa6_embedscope(fin6, V_ip6_use_defzone);
3933 		if (error)
3934 			return (error);
3935 		error = sa6_embedscope(lin6, V_ip6_use_defzone);
3936 		if (error)
3937 			return (error);
3938 		break;
3939 #endif
3940 #ifdef INET
3941 	case AF_INET:
3942 		fin = (struct sockaddr_in *)&addrs[0];
3943 		lin = (struct sockaddr_in *)&addrs[1];
3944 		if (fin->sin_len != sizeof(struct sockaddr_in) ||
3945 		    lin->sin_len != sizeof(struct sockaddr_in))
3946 			return (EINVAL);
3947 		break;
3948 #endif
3949 	default:
3950 		return (EINVAL);
3951 	}
3952 	NET_EPOCH_ENTER(et);
3953 	switch (addrs[0].ss_family) {
3954 #ifdef INET6
3955 	case AF_INET6:
3956 		inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
3957 		    fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
3958 		    INPLOOKUP_WLOCKPCB, NULL);
3959 		break;
3960 #endif
3961 #ifdef INET
3962 	case AF_INET:
3963 		inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
3964 		    lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
3965 		break;
3966 #endif
3967 	}
3968 	if (inp != NULL) {
3969 		if (!SOLISTENING(inp->inp_socket)) {
3970 			tp = intotcpcb(inp);
3971 			tp = tcp_drop(tp, ECONNABORTED);
3972 			if (tp != NULL)
3973 				INP_WUNLOCK(inp);
3974 		} else
3975 			INP_WUNLOCK(inp);
3976 	} else
3977 		error = ESRCH;
3978 	NET_EPOCH_EXIT(et);
3979 	return (error);
3980 }
3981 
3982 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
3983     CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
3984     CTLFLAG_NEEDGIANT, NULL, 0, sysctl_drop, "",
3985     "Drop TCP connection");
3986 
3987 static int
3988 tcp_sysctl_setsockopt(SYSCTL_HANDLER_ARGS)
3989 {
3990 	return (sysctl_setsockopt(oidp, arg1, arg2, req, &V_tcbinfo,
3991 	    &tcp_ctloutput_set));
3992 }
3993 
3994 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, setsockopt,
3995     CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
3996     CTLFLAG_MPSAFE, NULL, 0, tcp_sysctl_setsockopt, "",
3997     "Set socket option for TCP endpoint");
3998 
3999 #ifdef KERN_TLS
4000 static int
4001 sysctl_switch_tls(SYSCTL_HANDLER_ARGS)
4002 {
4003 	/* addrs[0] is a foreign socket, addrs[1] is a local one. */
4004 	struct sockaddr_storage addrs[2];
4005 	struct inpcb *inp;
4006 #ifdef INET
4007 	struct sockaddr_in *fin = NULL, *lin = NULL;
4008 #endif
4009 	struct epoch_tracker et;
4010 #ifdef INET6
4011 	struct sockaddr_in6 *fin6, *lin6;
4012 #endif
4013 	int error;
4014 
4015 	inp = NULL;
4016 #ifdef INET6
4017 	fin6 = lin6 = NULL;
4018 #endif
4019 	error = 0;
4020 
4021 	if (req->oldptr != NULL || req->oldlen != 0)
4022 		return (EINVAL);
4023 	if (req->newptr == NULL)
4024 		return (EPERM);
4025 	if (req->newlen < sizeof(addrs))
4026 		return (ENOMEM);
4027 	error = SYSCTL_IN(req, &addrs, sizeof(addrs));
4028 	if (error)
4029 		return (error);
4030 
4031 	switch (addrs[0].ss_family) {
4032 #ifdef INET6
4033 	case AF_INET6:
4034 		fin6 = (struct sockaddr_in6 *)&addrs[0];
4035 		lin6 = (struct sockaddr_in6 *)&addrs[1];
4036 		if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
4037 		    lin6->sin6_len != sizeof(struct sockaddr_in6))
4038 			return (EINVAL);
4039 		if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
4040 			if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
4041 				return (EINVAL);
4042 			in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
4043 			in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
4044 #ifdef INET
4045 			fin = (struct sockaddr_in *)&addrs[0];
4046 			lin = (struct sockaddr_in *)&addrs[1];
4047 #endif
4048 			break;
4049 		}
4050 		error = sa6_embedscope(fin6, V_ip6_use_defzone);
4051 		if (error)
4052 			return (error);
4053 		error = sa6_embedscope(lin6, V_ip6_use_defzone);
4054 		if (error)
4055 			return (error);
4056 		break;
4057 #endif
4058 #ifdef INET
4059 	case AF_INET:
4060 		fin = (struct sockaddr_in *)&addrs[0];
4061 		lin = (struct sockaddr_in *)&addrs[1];
4062 		if (fin->sin_len != sizeof(struct sockaddr_in) ||
4063 		    lin->sin_len != sizeof(struct sockaddr_in))
4064 			return (EINVAL);
4065 		break;
4066 #endif
4067 	default:
4068 		return (EINVAL);
4069 	}
4070 	NET_EPOCH_ENTER(et);
4071 	switch (addrs[0].ss_family) {
4072 #ifdef INET6
4073 	case AF_INET6:
4074 		inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
4075 		    fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
4076 		    INPLOOKUP_WLOCKPCB, NULL);
4077 		break;
4078 #endif
4079 #ifdef INET
4080 	case AF_INET:
4081 		inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
4082 		    lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
4083 		break;
4084 #endif
4085 	}
4086 	NET_EPOCH_EXIT(et);
4087 	if (inp != NULL) {
4088 		struct socket *so;
4089 
4090 		so = inp->inp_socket;
4091 		soref(so);
4092 		error = ktls_set_tx_mode(so,
4093 		    arg2 == 0 ? TCP_TLS_MODE_SW : TCP_TLS_MODE_IFNET);
4094 		INP_WUNLOCK(inp);
4095 		sorele(so);
4096 	} else
4097 		error = ESRCH;
4098 	return (error);
4099 }
4100 
4101 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, switch_to_sw_tls,
4102     CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
4103     CTLFLAG_NEEDGIANT, NULL, 0, sysctl_switch_tls, "",
4104     "Switch TCP connection to SW TLS");
4105 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, switch_to_ifnet_tls,
4106     CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
4107     CTLFLAG_NEEDGIANT, NULL, 1, sysctl_switch_tls, "",
4108     "Switch TCP connection to ifnet TLS");
4109 #endif
4110 
4111 /*
4112  * Generate a standardized TCP log line for use throughout the
4113  * tcp subsystem.  Memory allocation is done with M_NOWAIT to
4114  * allow use in the interrupt context.
4115  *
4116  * NB: The caller MUST free(s, M_TCPLOG) the returned string.
4117  * NB: The function may return NULL if memory allocation failed.
4118  *
4119  * Due to header inclusion and ordering limitations the struct ip
4120  * and ip6_hdr pointers have to be passed as void pointers.
4121  */
4122 char *
4123 tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, const void *ip4hdr,
4124     const void *ip6hdr)
4125 {
4126 
4127 	/* Is logging enabled? */
4128 	if (V_tcp_log_in_vain == 0)
4129 		return (NULL);
4130 
4131 	return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
4132 }
4133 
4134 char *
4135 tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, const void *ip4hdr,
4136     const void *ip6hdr)
4137 {
4138 
4139 	/* Is logging enabled? */
4140 	if (tcp_log_debug == 0)
4141 		return (NULL);
4142 
4143 	return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
4144 }
4145 
4146 static char *
4147 tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, const void *ip4hdr,
4148     const void *ip6hdr)
4149 {
4150 	char *s, *sp;
4151 	size_t size;
4152 #ifdef INET
4153 	const struct ip *ip = (const struct ip *)ip4hdr;
4154 #endif
4155 #ifdef INET6
4156 	const struct ip6_hdr *ip6 = (const struct ip6_hdr *)ip6hdr;
4157 #endif /* INET6 */
4158 
4159 	/*
4160 	 * The log line looks like this:
4161 	 * "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>"
4162 	 */
4163 	size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") +
4164 	    sizeof(PRINT_TH_FLAGS) + 1 +
4165 #ifdef INET6
4166 	    2 * INET6_ADDRSTRLEN;
4167 #else
4168 	    2 * INET_ADDRSTRLEN;
4169 #endif /* INET6 */
4170 
4171 	s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT);
4172 	if (s == NULL)
4173 		return (NULL);
4174 
4175 	strcat(s, "TCP: [");
4176 	sp = s + strlen(s);
4177 
4178 	if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) {
4179 		inet_ntoa_r(inc->inc_faddr, sp);
4180 		sp = s + strlen(s);
4181 		sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
4182 		sp = s + strlen(s);
4183 		inet_ntoa_r(inc->inc_laddr, sp);
4184 		sp = s + strlen(s);
4185 		sprintf(sp, "]:%i", ntohs(inc->inc_lport));
4186 #ifdef INET6
4187 	} else if (inc) {
4188 		ip6_sprintf(sp, &inc->inc6_faddr);
4189 		sp = s + strlen(s);
4190 		sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
4191 		sp = s + strlen(s);
4192 		ip6_sprintf(sp, &inc->inc6_laddr);
4193 		sp = s + strlen(s);
4194 		sprintf(sp, "]:%i", ntohs(inc->inc_lport));
4195 	} else if (ip6 && th) {
4196 		ip6_sprintf(sp, &ip6->ip6_src);
4197 		sp = s + strlen(s);
4198 		sprintf(sp, "]:%i to [", ntohs(th->th_sport));
4199 		sp = s + strlen(s);
4200 		ip6_sprintf(sp, &ip6->ip6_dst);
4201 		sp = s + strlen(s);
4202 		sprintf(sp, "]:%i", ntohs(th->th_dport));
4203 #endif /* INET6 */
4204 #ifdef INET
4205 	} else if (ip && th) {
4206 		inet_ntoa_r(ip->ip_src, sp);
4207 		sp = s + strlen(s);
4208 		sprintf(sp, "]:%i to [", ntohs(th->th_sport));
4209 		sp = s + strlen(s);
4210 		inet_ntoa_r(ip->ip_dst, sp);
4211 		sp = s + strlen(s);
4212 		sprintf(sp, "]:%i", ntohs(th->th_dport));
4213 #endif /* INET */
4214 	} else {
4215 		free(s, M_TCPLOG);
4216 		return (NULL);
4217 	}
4218 	sp = s + strlen(s);
4219 	if (th)
4220 		sprintf(sp, " tcpflags 0x%b", tcp_get_flags(th), PRINT_TH_FLAGS);
4221 	if (*(s + size - 1) != '\0')
4222 		panic("%s: string too long", __func__);
4223 	return (s);
4224 }
4225 
4226 /*
4227  * A subroutine which makes it easy to track TCP state changes with DTrace.
4228  * This function shouldn't be called for t_state initializations that don't
4229  * correspond to actual TCP state transitions.
4230  */
4231 void
4232 tcp_state_change(struct tcpcb *tp, int newstate)
4233 {
4234 #if defined(KDTRACE_HOOKS)
4235 	int pstate = tp->t_state;
4236 #endif
4237 
4238 	TCPSTATES_DEC(tp->t_state);
4239 	TCPSTATES_INC(newstate);
4240 	tp->t_state = newstate;
4241 	TCP_PROBE6(state__change, NULL, tp, NULL, tp, NULL, pstate);
4242 }
4243 
4244 /*
4245  * Create an external-format (``xtcpcb'') structure using the information in
4246  * the kernel-format tcpcb structure pointed to by tp.  This is done to
4247  * reduce the spew of irrelevant information over this interface, to isolate
4248  * user code from changes in the kernel structure, and potentially to provide
4249  * information-hiding if we decide that some of this information should be
4250  * hidden from users.
4251  */
4252 void
4253 tcp_inptoxtp(const struct inpcb *inp, struct xtcpcb *xt)
4254 {
4255 	struct tcpcb *tp = intotcpcb(inp);
4256 	sbintime_t now;
4257 
4258 	bzero(xt, sizeof(*xt));
4259 	xt->t_state = tp->t_state;
4260 	xt->t_logstate = tcp_get_bblog_state(tp);
4261 	xt->t_flags = tp->t_flags;
4262 	xt->t_sndzerowin = tp->t_sndzerowin;
4263 	xt->t_sndrexmitpack = tp->t_sndrexmitpack;
4264 	xt->t_rcvoopack = tp->t_rcvoopack;
4265 	xt->t_rcv_wnd = tp->rcv_wnd;
4266 	xt->t_snd_wnd = tp->snd_wnd;
4267 	xt->t_snd_cwnd = tp->snd_cwnd;
4268 	xt->t_snd_ssthresh = tp->snd_ssthresh;
4269 	xt->t_dsack_bytes = tp->t_dsack_bytes;
4270 	xt->t_dsack_tlp_bytes = tp->t_dsack_tlp_bytes;
4271 	xt->t_dsack_pack = tp->t_dsack_pack;
4272 	xt->t_maxseg = tp->t_maxseg;
4273 	xt->xt_ecn = (tp->t_flags2 & TF2_ECN_PERMIT) ? 1 : 0 +
4274 		     (tp->t_flags2 & TF2_ACE_PERMIT) ? 2 : 0;
4275 
4276 	now = getsbinuptime();
4277 #define	COPYTIMER(which,where)	do {					\
4278 	if (tp->t_timers[which] != SBT_MAX)				\
4279 		xt->where = (tp->t_timers[which] - now) / SBT_1MS;	\
4280 	else								\
4281 		xt->where = 0;						\
4282 } while (0)
4283 	COPYTIMER(TT_DELACK, tt_delack);
4284 	COPYTIMER(TT_REXMT, tt_rexmt);
4285 	COPYTIMER(TT_PERSIST, tt_persist);
4286 	COPYTIMER(TT_KEEP, tt_keep);
4287 	COPYTIMER(TT_2MSL, tt_2msl);
4288 #undef COPYTIMER
4289 	xt->t_rcvtime = 1000 * (ticks - tp->t_rcvtime) / hz;
4290 
4291 	xt->xt_encaps_port = tp->t_port;
4292 	bcopy(tp->t_fb->tfb_tcp_block_name, xt->xt_stack,
4293 	    TCP_FUNCTION_NAME_LEN_MAX);
4294 	bcopy(CC_ALGO(tp)->name, xt->xt_cc, TCP_CA_NAME_MAX);
4295 #ifdef TCP_BLACKBOX
4296 	(void)tcp_log_get_id(tp, xt->xt_logid);
4297 #endif
4298 
4299 	xt->xt_len = sizeof(struct xtcpcb);
4300 	in_pcbtoxinpcb(inp, &xt->xt_inp);
4301 }
4302 
4303 void
4304 tcp_log_end_status(struct tcpcb *tp, uint8_t status)
4305 {
4306 	uint32_t bit, i;
4307 
4308 	if ((tp == NULL) ||
4309 	    (status > TCP_EI_STATUS_MAX_VALUE) ||
4310 	    (status == 0)) {
4311 		/* Invalid */
4312 		return;
4313 	}
4314 	if (status > (sizeof(uint32_t) * 8)) {
4315 		/* Should this be a KASSERT? */
4316 		return;
4317 	}
4318 	bit = 1U << (status - 1);
4319 	if (bit & tp->t_end_info_status) {
4320 		/* already logged */
4321 		return;
4322 	}
4323 	for (i = 0; i < TCP_END_BYTE_INFO; i++) {
4324 		if (tp->t_end_info_bytes[i] == TCP_EI_EMPTY_SLOT) {
4325 			tp->t_end_info_bytes[i] = status;
4326 			tp->t_end_info_status |= bit;
4327 			break;
4328 		}
4329 	}
4330 }
4331 
4332 int
4333 tcp_can_enable_pacing(void)
4334 {
4335 
4336 	if ((tcp_pacing_limit == -1) ||
4337 	    (tcp_pacing_limit > number_of_tcp_connections_pacing)) {
4338 		atomic_fetchadd_int(&number_of_tcp_connections_pacing, 1);
4339 		shadow_num_connections = number_of_tcp_connections_pacing;
4340 		return (1);
4341 	} else {
4342 		counter_u64_add(tcp_pacing_failures, 1);
4343 		return (0);
4344 	}
4345 }
4346 
4347 int
4348 tcp_incr_dgp_pacing_cnt(void)
4349 {
4350 	if ((tcp_dgp_limit == -1) ||
4351 	    (tcp_dgp_limit > number_of_dgp_connections)) {
4352 		atomic_fetchadd_int(&number_of_dgp_connections, 1);
4353 		shadow_tcp_pacing_dgp = number_of_dgp_connections;
4354 		return (1);
4355 	} else {
4356 		counter_u64_add(tcp_dgp_failures, 1);
4357 		return (0);
4358 	}
4359 }
4360 
4361 static uint8_t tcp_dgp_warning = 0;
4362 
4363 void
4364 tcp_dec_dgp_pacing_cnt(void)
4365 {
4366 	uint32_t ret;
4367 
4368 	ret = atomic_fetchadd_int(&number_of_dgp_connections, -1);
4369 	shadow_tcp_pacing_dgp = number_of_dgp_connections;
4370 	KASSERT(ret != 0, ("number_of_dgp_connections -1 would cause wrap?"));
4371 	if (ret == 0) {
4372 		if (tcp_dgp_limit != -1) {
4373 			printf("Warning all DGP is now disabled, count decrements invalidly!\n");
4374 			tcp_dgp_limit = 0;
4375 			tcp_dgp_warning = 1;
4376 		} else if (tcp_dgp_warning == 0) {
4377 			printf("Warning DGP pacing is invalid, invalid decrement\n");
4378 			tcp_dgp_warning = 1;
4379 		}
4380 	}
4381 
4382 }
4383 
4384 static uint8_t tcp_pacing_warning = 0;
4385 
4386 void
4387 tcp_decrement_paced_conn(void)
4388 {
4389 	uint32_t ret;
4390 
4391 	ret = atomic_fetchadd_int(&number_of_tcp_connections_pacing, -1);
4392 	shadow_num_connections = number_of_tcp_connections_pacing;
4393 	KASSERT(ret != 0, ("tcp_paced_connection_exits -1 would cause wrap?"));
4394 	if (ret == 0) {
4395 		if (tcp_pacing_limit != -1) {
4396 			printf("Warning all pacing is now disabled, count decrements invalidly!\n");
4397 			tcp_pacing_limit = 0;
4398 		} else if (tcp_pacing_warning == 0) {
4399 			printf("Warning pacing count is invalid, invalid decrement\n");
4400 			tcp_pacing_warning = 1;
4401 		}
4402 	}
4403 }
4404 
4405 static void
4406 tcp_default_switch_failed(struct tcpcb *tp)
4407 {
4408 	/*
4409 	 * If a switch fails we only need to
4410 	 * care about two things:
4411 	 * a) The t_flags2
4412 	 * and
4413 	 * b) The timer granularity.
4414 	 * Timeouts, at least for now, don't use the
4415 	 * old callout system in the other stacks so
4416 	 * those are hopefully safe.
4417 	 */
4418 	tcp_lro_features_off(tp);
4419 	tcp_change_time_units(tp, TCP_TMR_GRANULARITY_TICKS);
4420 }
4421 
4422 #ifdef TCP_ACCOUNTING
4423 int
4424 tcp_do_ack_accounting(struct tcpcb *tp, struct tcphdr *th, struct tcpopt *to, uint32_t tiwin, int mss)
4425 {
4426 	if (SEQ_LT(th->th_ack, tp->snd_una)) {
4427 		/* Do we have a SACK? */
4428 		if (to->to_flags & TOF_SACK) {
4429 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
4430 				tp->tcp_cnt_counters[ACK_SACK]++;
4431 			}
4432 			return (ACK_SACK);
4433 		} else {
4434 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
4435 				tp->tcp_cnt_counters[ACK_BEHIND]++;
4436 			}
4437 			return (ACK_BEHIND);
4438 		}
4439 	} else if (th->th_ack == tp->snd_una) {
4440 		/* Do we have a SACK? */
4441 		if (to->to_flags & TOF_SACK) {
4442 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
4443 				tp->tcp_cnt_counters[ACK_SACK]++;
4444 			}
4445 			return (ACK_SACK);
4446 		} else if (tiwin != tp->snd_wnd) {
4447 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
4448 				tp->tcp_cnt_counters[ACK_RWND]++;
4449 			}
4450 			return (ACK_RWND);
4451 		} else {
4452 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
4453 				tp->tcp_cnt_counters[ACK_DUPACK]++;
4454 			}
4455 			return (ACK_DUPACK);
4456 		}
4457 	} else {
4458 		if (!SEQ_GT(th->th_ack, tp->snd_max)) {
4459 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
4460 				tp->tcp_cnt_counters[CNT_OF_ACKS_IN] += (((th->th_ack - tp->snd_una) + mss - 1)/mss);
4461 			}
4462 		}
4463 		if (to->to_flags & TOF_SACK) {
4464 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
4465 				tp->tcp_cnt_counters[ACK_CUMACK_SACK]++;
4466 			}
4467 			return (ACK_CUMACK_SACK);
4468 		} else {
4469 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
4470 				tp->tcp_cnt_counters[ACK_CUMACK]++;
4471 			}
4472 			return (ACK_CUMACK);
4473 		}
4474 	}
4475 }
4476 #endif
4477 
4478 void
4479 tcp_change_time_units(struct tcpcb *tp, int granularity)
4480 {
4481 	if (tp->t_tmr_granularity == granularity) {
4482 		/* We are there */
4483 		return;
4484 	}
4485 	if (granularity == TCP_TMR_GRANULARITY_USEC) {
4486 		KASSERT((tp->t_tmr_granularity == TCP_TMR_GRANULARITY_TICKS),
4487 			("Granularity is not TICKS its %u in tp:%p",
4488 			 tp->t_tmr_granularity, tp));
4489 		tp->t_rttlow = TICKS_2_USEC(tp->t_rttlow);
4490 		if (tp->t_srtt > 1) {
4491 			uint32_t val, frac;
4492 
4493 			val = tp->t_srtt >> TCP_RTT_SHIFT;
4494 			frac = tp->t_srtt & 0x1f;
4495 			tp->t_srtt = TICKS_2_USEC(val);
4496 			/*
4497 			 * frac is the fractional part of the srtt (if any)
4498 			 * but its in ticks and every bit represents
4499 			 * 1/32nd of a hz.
4500 			 */
4501 			if (frac) {
4502 				if (hz == 1000) {
4503 					frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_MSEC) / (uint64_t)TCP_RTT_SCALE);
4504 				} else {
4505 					frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_SEC) / ((uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE));
4506 				}
4507 				tp->t_srtt += frac;
4508 			}
4509 		}
4510 		if (tp->t_rttvar) {
4511 			uint32_t val, frac;
4512 
4513 			val = tp->t_rttvar >> TCP_RTTVAR_SHIFT;
4514 			frac = tp->t_rttvar & 0x1f;
4515 			tp->t_rttvar = TICKS_2_USEC(val);
4516 			/*
4517 			 * frac is the fractional part of the srtt (if any)
4518 			 * but its in ticks and every bit represents
4519 			 * 1/32nd of a hz.
4520 			 */
4521 			if (frac) {
4522 				if (hz == 1000) {
4523 					frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_MSEC) / (uint64_t)TCP_RTT_SCALE);
4524 				} else {
4525 					frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_SEC) / ((uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE));
4526 				}
4527 				tp->t_rttvar += frac;
4528 			}
4529 		}
4530 		tp->t_tmr_granularity = TCP_TMR_GRANULARITY_USEC;
4531 	} else if (granularity == TCP_TMR_GRANULARITY_TICKS) {
4532 		/* Convert back to ticks, with  */
4533 		KASSERT((tp->t_tmr_granularity == TCP_TMR_GRANULARITY_USEC),
4534 			("Granularity is not USEC its %u in tp:%p",
4535 			 tp->t_tmr_granularity, tp));
4536 		if (tp->t_srtt > 1) {
4537 			uint32_t val, frac;
4538 
4539 			val = USEC_2_TICKS(tp->t_srtt);
4540 			frac = tp->t_srtt % (HPTS_USEC_IN_SEC / hz);
4541 			tp->t_srtt = val << TCP_RTT_SHIFT;
4542 			/*
4543 			 * frac is the fractional part here is left
4544 			 * over from converting to hz and shifting.
4545 			 * We need to convert this to the 5 bit
4546 			 * remainder.
4547 			 */
4548 			if (frac) {
4549 				if (hz == 1000) {
4550 					frac = (((uint64_t)frac *  (uint64_t)TCP_RTT_SCALE) / (uint64_t)HPTS_USEC_IN_MSEC);
4551 				} else {
4552 					frac = (((uint64_t)frac * (uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE) /(uint64_t)HPTS_USEC_IN_SEC);
4553 				}
4554 				tp->t_srtt += frac;
4555 			}
4556 		}
4557 		if (tp->t_rttvar) {
4558 			uint32_t val, frac;
4559 
4560 			val = USEC_2_TICKS(tp->t_rttvar);
4561 			frac = tp->t_rttvar % (HPTS_USEC_IN_SEC / hz);
4562 			tp->t_rttvar = val <<  TCP_RTTVAR_SHIFT;
4563 			/*
4564 			 * frac is the fractional part here is left
4565 			 * over from converting to hz and shifting.
4566 			 * We need to convert this to the 4 bit
4567 			 * remainder.
4568 			 */
4569 			if (frac) {
4570 				if (hz == 1000) {
4571 					frac = (((uint64_t)frac *  (uint64_t)TCP_RTTVAR_SCALE) / (uint64_t)HPTS_USEC_IN_MSEC);
4572 				} else {
4573 					frac = (((uint64_t)frac * (uint64_t)(hz) * (uint64_t)TCP_RTTVAR_SCALE) /(uint64_t)HPTS_USEC_IN_SEC);
4574 				}
4575 				tp->t_rttvar += frac;
4576 			}
4577 		}
4578 		tp->t_rttlow = USEC_2_TICKS(tp->t_rttlow);
4579 		tp->t_tmr_granularity = TCP_TMR_GRANULARITY_TICKS;
4580 	}
4581 #ifdef INVARIANTS
4582 	else {
4583 		panic("Unknown granularity:%d tp:%p",
4584 		      granularity, tp);
4585 	}
4586 #endif
4587 }
4588 
4589 void
4590 tcp_handle_orphaned_packets(struct tcpcb *tp)
4591 {
4592 	struct mbuf *save, *m, *prev;
4593 	/*
4594 	 * Called when a stack switch is occuring from the fini()
4595 	 * of the old stack. We assue the init() as already been
4596 	 * run of the new stack and it has set the t_flags2 to
4597 	 * what it supports. This function will then deal with any
4598 	 * differences i.e. cleanup packets that maybe queued that
4599 	 * the newstack does not support.
4600 	 */
4601 
4602 	if (tp->t_flags2 & TF2_MBUF_L_ACKS)
4603 		return;
4604 	if ((tp->t_flags2 & TF2_SUPPORTS_MBUFQ) == 0 &&
4605 	    !STAILQ_EMPTY(&tp->t_inqueue)) {
4606 		/*
4607 		 * It is unsafe to process the packets since a
4608 		 * reset may be lurking in them (its rare but it
4609 		 * can occur). If we were to find a RST, then we
4610 		 * would end up dropping the connection and the
4611 		 * INP lock, so when we return the caller (tcp_usrreq)
4612 		 * will blow up when it trys to unlock the inp.
4613 		 * This new stack does not do any fancy LRO features
4614 		 * so all we can do is toss the packets.
4615 		 */
4616 		m = STAILQ_FIRST(&tp->t_inqueue);
4617 		STAILQ_INIT(&tp->t_inqueue);
4618 		STAILQ_FOREACH_FROM_SAFE(m, &tp->t_inqueue, m_stailqpkt, save)
4619 			m_freem(m);
4620 	} else {
4621 		/*
4622 		 * Here we have a stack that does mbuf queuing but
4623 		 * does not support compressed ack's. We must
4624 		 * walk all the mbufs and discard any compressed acks.
4625 		 */
4626 		STAILQ_FOREACH_SAFE(m, &tp->t_inqueue, m_stailqpkt, save) {
4627 			if (m->m_flags & M_ACKCMP) {
4628 				if (m == STAILQ_FIRST(&tp->t_inqueue))
4629 					STAILQ_REMOVE_HEAD(&tp->t_inqueue,
4630 					    m_stailqpkt);
4631 				else
4632 					STAILQ_REMOVE_AFTER(&tp->t_inqueue,
4633 					    prev, m_stailqpkt);
4634 				m_freem(m);
4635 			} else
4636 				prev = m;
4637 		}
4638 	}
4639 }
4640 
4641 #ifdef TCP_REQUEST_TRK
4642 uint32_t
4643 tcp_estimate_tls_overhead(struct socket *so, uint64_t tls_usr_bytes)
4644 {
4645 #ifdef KERN_TLS
4646 	struct ktls_session *tls;
4647 	uint32_t rec_oh, records;
4648 
4649 	tls = so->so_snd.sb_tls_info;
4650 	if (tls == NULL)
4651 	    return (0);
4652 
4653 	rec_oh = tls->params.tls_hlen + tls->params.tls_tlen;
4654 	records = ((tls_usr_bytes + tls->params.max_frame_len - 1)/tls->params.max_frame_len);
4655 	return (records * rec_oh);
4656 #else
4657 	return (0);
4658 #endif
4659 }
4660 
4661 extern uint32_t tcp_stale_entry_time;
4662 uint32_t tcp_stale_entry_time = 250000;
4663 SYSCTL_UINT(_net_inet_tcp, OID_AUTO, usrlog_stale, CTLFLAG_RW,
4664     &tcp_stale_entry_time, 250000, "Time that a tcpreq entry without a sendfile ages out");
4665 
4666 void
4667 tcp_req_log_req_info(struct tcpcb *tp, struct tcp_sendfile_track *req,
4668     uint16_t slot, uint8_t val, uint64_t offset, uint64_t nbytes)
4669 {
4670 	if (tcp_bblogging_on(tp)) {
4671 		union tcp_log_stackspecific log;
4672 		struct timeval tv;
4673 
4674 		memset(&log, 0, sizeof(log));
4675 		log.u_bbr.inhpts = tcp_in_hpts(tp);
4676 		log.u_bbr.flex8 = val;
4677 		log.u_bbr.rttProp = req->timestamp;
4678 		log.u_bbr.delRate = req->start;
4679 		log.u_bbr.cur_del_rate = req->end;
4680 		log.u_bbr.flex1 = req->start_seq;
4681 		log.u_bbr.flex2 = req->end_seq;
4682 		log.u_bbr.flex3 = req->flags;
4683 		log.u_bbr.flex4 = ((req->localtime >> 32) & 0x00000000ffffffff);
4684 		log.u_bbr.flex5 = (req->localtime & 0x00000000ffffffff);
4685 		log.u_bbr.flex7 = slot;
4686 		log.u_bbr.bw_inuse = offset;
4687 		/* nbytes = flex6 | epoch */
4688 		log.u_bbr.flex6 = ((nbytes >> 32) & 0x00000000ffffffff);
4689 		log.u_bbr.epoch = (nbytes & 0x00000000ffffffff);
4690 		/* cspr =  lt_epoch | pkts_out */
4691 		log.u_bbr.lt_epoch = ((req->cspr >> 32) & 0x00000000ffffffff);
4692 		log.u_bbr.pkts_out |= (req->cspr & 0x00000000ffffffff);
4693 		log.u_bbr.applimited = tp->t_tcpreq_closed;
4694 		log.u_bbr.applimited <<= 8;
4695 		log.u_bbr.applimited |= tp->t_tcpreq_open;
4696 		log.u_bbr.applimited <<= 8;
4697 		log.u_bbr.applimited |= tp->t_tcpreq_req;
4698 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
4699 		TCP_LOG_EVENTP(tp, NULL,
4700 		    &tptosocket(tp)->so_rcv,
4701 		    &tptosocket(tp)->so_snd,
4702 		    TCP_LOG_REQ_T, 0,
4703 		    0, &log, false, &tv);
4704 	}
4705 }
4706 
4707 void
4708 tcp_req_free_a_slot(struct tcpcb *tp, struct tcp_sendfile_track *ent)
4709 {
4710 	if (tp->t_tcpreq_req > 0)
4711 		tp->t_tcpreq_req--;
4712 	if (ent->flags & TCP_TRK_TRACK_FLG_OPEN) {
4713 		if (tp->t_tcpreq_open > 0)
4714 			tp->t_tcpreq_open--;
4715 	} else {
4716 		if (tp->t_tcpreq_closed > 0)
4717 			tp->t_tcpreq_closed--;
4718 	}
4719 	ent->flags = TCP_TRK_TRACK_FLG_EMPTY;
4720 }
4721 
4722 static void
4723 tcp_req_check_for_stale_entries(struct tcpcb *tp, uint64_t ts, int rm_oldest)
4724 {
4725 	struct tcp_sendfile_track *ent;
4726 	uint64_t time_delta, oldest_delta;
4727 	int i, oldest, oldest_set = 0, cnt_rm = 0;
4728 
4729 	for (i = 0; i < MAX_TCP_TRK_REQ; i++) {
4730 		ent = &tp->t_tcpreq_info[i];
4731 		if (ent->flags != TCP_TRK_TRACK_FLG_USED) {
4732 			/*
4733 			 * We only care about closed end ranges
4734 			 * that are allocated and have no sendfile
4735 			 * ever touching them. They would be in
4736 			 * state USED.
4737 			 */
4738 			continue;
4739 		}
4740 		if (ts >= ent->localtime)
4741 			time_delta = ts - ent->localtime;
4742 		else
4743 			time_delta = 0;
4744 		if (time_delta &&
4745 		    ((oldest_delta < time_delta) || (oldest_set == 0))) {
4746 			oldest_set = 1;
4747 			oldest = i;
4748 			oldest_delta = time_delta;
4749 		}
4750 		if (tcp_stale_entry_time && (time_delta >= tcp_stale_entry_time)) {
4751 			/*
4752 			 * No sendfile in a our time-limit
4753 			 * time to purge it.
4754 			 */
4755 			cnt_rm++;
4756 			tcp_req_log_req_info(tp, &tp->t_tcpreq_info[i], i, TCP_TRK_REQ_LOG_STALE,
4757 					      time_delta, 0);
4758 			tcp_req_free_a_slot(tp, ent);
4759 		}
4760 	}
4761 	if ((cnt_rm == 0) && rm_oldest && oldest_set) {
4762 		ent = &tp->t_tcpreq_info[oldest];
4763 		tcp_req_log_req_info(tp, &tp->t_tcpreq_info[i], i, TCP_TRK_REQ_LOG_STALE,
4764 				      oldest_delta, 1);
4765 		tcp_req_free_a_slot(tp, ent);
4766 	}
4767 }
4768 
4769 int
4770 tcp_req_check_for_comp(struct tcpcb *tp, tcp_seq ack_point)
4771 {
4772 	int i, ret = 0;
4773 	struct tcp_sendfile_track *ent;
4774 
4775 	/* Clean up any old closed end requests that are now completed */
4776 	if (tp->t_tcpreq_req == 0)
4777 		return (0);
4778 	if (tp->t_tcpreq_closed == 0)
4779 		return (0);
4780 	for (i = 0; i < MAX_TCP_TRK_REQ; i++) {
4781 		ent = &tp->t_tcpreq_info[i];
4782 		/* Skip empty ones */
4783 		if (ent->flags == TCP_TRK_TRACK_FLG_EMPTY)
4784 			continue;
4785 		/* Skip open ones */
4786 		if (ent->flags & TCP_TRK_TRACK_FLG_OPEN)
4787 			continue;
4788 		if (SEQ_GEQ(ack_point, ent->end_seq)) {
4789 			/* We are past it -- free it */
4790 			tcp_req_log_req_info(tp, ent,
4791 					      i, TCP_TRK_REQ_LOG_FREED, 0, 0);
4792 			tcp_req_free_a_slot(tp, ent);
4793 			ret++;
4794 		}
4795 	}
4796 	return (ret);
4797 }
4798 
4799 int
4800 tcp_req_is_entry_comp(struct tcpcb *tp, struct tcp_sendfile_track *ent, tcp_seq ack_point)
4801 {
4802 	if (tp->t_tcpreq_req == 0)
4803 		return (-1);
4804 	if (tp->t_tcpreq_closed == 0)
4805 		return (-1);
4806 	if (ent->flags == TCP_TRK_TRACK_FLG_EMPTY)
4807 		return (-1);
4808 	if (SEQ_GEQ(ack_point, ent->end_seq)) {
4809 		return (1);
4810 	}
4811 	return (0);
4812 }
4813 
4814 struct tcp_sendfile_track *
4815 tcp_req_find_a_req_that_is_completed_by(struct tcpcb *tp, tcp_seq th_ack, int *ip)
4816 {
4817 	/*
4818 	 * Given an ack point (th_ack) walk through our entries and
4819 	 * return the first one found that th_ack goes past the
4820 	 * end_seq.
4821 	 */
4822 	struct tcp_sendfile_track *ent;
4823 	int i;
4824 
4825 	if (tp->t_tcpreq_req == 0) {
4826 		/* none open */
4827 		return (NULL);
4828 	}
4829 	for (i = 0; i < MAX_TCP_TRK_REQ; i++) {
4830 		ent = &tp->t_tcpreq_info[i];
4831 		if (ent->flags == TCP_TRK_TRACK_FLG_EMPTY)
4832 			continue;
4833 		if ((ent->flags & TCP_TRK_TRACK_FLG_OPEN) == 0) {
4834 			if (SEQ_GEQ(th_ack, ent->end_seq)) {
4835 				*ip = i;
4836 				return (ent);
4837 			}
4838 		}
4839 	}
4840 	return (NULL);
4841 }
4842 
4843 struct tcp_sendfile_track *
4844 tcp_req_find_req_for_seq(struct tcpcb *tp, tcp_seq seq)
4845 {
4846 	struct tcp_sendfile_track *ent;
4847 	int i;
4848 
4849 	if (tp->t_tcpreq_req == 0) {
4850 		/* none open */
4851 		return (NULL);
4852 	}
4853 	for (i = 0; i < MAX_TCP_TRK_REQ; i++) {
4854 		ent = &tp->t_tcpreq_info[i];
4855 		tcp_req_log_req_info(tp, ent, i, TCP_TRK_REQ_LOG_SEARCH,
4856 				      (uint64_t)seq, 0);
4857 		if (ent->flags == TCP_TRK_TRACK_FLG_EMPTY) {
4858 			continue;
4859 		}
4860 		if (ent->flags & TCP_TRK_TRACK_FLG_OPEN) {
4861 			/*
4862 			 * An open end request only needs to
4863 			 * match the beginning seq or be
4864 			 * all we have (once we keep going on
4865 			 * a open end request we may have a seq
4866 			 * wrap).
4867 			 */
4868 			if ((SEQ_GEQ(seq, ent->start_seq)) ||
4869 			    (tp->t_tcpreq_closed == 0))
4870 				return (ent);
4871 		} else {
4872 			/*
4873 			 * For this one we need to
4874 			 * be a bit more careful if its
4875 			 * completed at least.
4876 			 */
4877 			if ((SEQ_GEQ(seq, ent->start_seq)) &&
4878 			    (SEQ_LT(seq, ent->end_seq))) {
4879 				return (ent);
4880 			}
4881 		}
4882 	}
4883 	return (NULL);
4884 }
4885 
4886 /* Should this be in its own file tcp_req.c ? */
4887 struct tcp_sendfile_track *
4888 tcp_req_alloc_req_full(struct tcpcb *tp, struct tcp_snd_req *req, uint64_t ts, int rec_dups)
4889 {
4890 	struct tcp_sendfile_track *fil;
4891 	int i, allocated;
4892 
4893 	/* In case the stack does not check for completions do so now */
4894 	tcp_req_check_for_comp(tp, tp->snd_una);
4895 	/* Check for stale entries */
4896 	if (tp->t_tcpreq_req)
4897 		tcp_req_check_for_stale_entries(tp, ts,
4898 		    (tp->t_tcpreq_req >= MAX_TCP_TRK_REQ));
4899 	/* Check to see if this is a duplicate of one not started */
4900 	if (tp->t_tcpreq_req) {
4901 		for (i = 0, allocated = 0; i < MAX_TCP_TRK_REQ; i++) {
4902 			fil = &tp->t_tcpreq_info[i];
4903 			if ((fil->flags & TCP_TRK_TRACK_FLG_USED) == 0)
4904 				continue;
4905 			if ((fil->timestamp == req->timestamp) &&
4906 			    (fil->start == req->start) &&
4907 			    ((fil->flags & TCP_TRK_TRACK_FLG_OPEN) ||
4908 			     (fil->end == req->end))) {
4909 				/*
4910 				 * We already have this request
4911 				 * and it has not been started with sendfile.
4912 				 * This probably means the user was returned
4913 				 * a 4xx of some sort and its going to age
4914 				 * out, lets not duplicate it.
4915 				 */
4916 				return (fil);
4917 			}
4918 		}
4919 	}
4920 	/* Ok if there is no room at the inn we are in trouble */
4921 	if (tp->t_tcpreq_req >= MAX_TCP_TRK_REQ) {
4922 		tcp_trace_point(tp, TCP_TP_REQ_LOG_FAIL);
4923 		for (i = 0; i < MAX_TCP_TRK_REQ; i++) {
4924 			tcp_req_log_req_info(tp, &tp->t_tcpreq_info[i],
4925 			    i, TCP_TRK_REQ_LOG_ALLOCFAIL, 0, 0);
4926 		}
4927 		return (NULL);
4928 	}
4929 	for (i = 0, allocated = 0; i < MAX_TCP_TRK_REQ; i++) {
4930 		fil = &tp->t_tcpreq_info[i];
4931 		if (fil->flags == TCP_TRK_TRACK_FLG_EMPTY) {
4932 			allocated = 1;
4933 			fil->flags = TCP_TRK_TRACK_FLG_USED;
4934 			fil->timestamp = req->timestamp;
4935 			fil->playout_ms = req->playout_ms;
4936 			fil->localtime = ts;
4937 			fil->start = req->start;
4938 			if (req->flags & TCP_LOG_HTTPD_RANGE_END) {
4939 				fil->end = req->end;
4940 			} else {
4941 				fil->end = 0;
4942 				fil->flags |= TCP_TRK_TRACK_FLG_OPEN;
4943 			}
4944 			/*
4945 			 * We can set the min boundaries to the TCP Sequence space,
4946 			 * but it might be found to be further up when sendfile
4947 			 * actually runs on this range (if it ever does).
4948 			 */
4949 			fil->sbcc_at_s = tptosocket(tp)->so_snd.sb_ccc;
4950 			fil->start_seq = tp->snd_una +
4951 			    tptosocket(tp)->so_snd.sb_ccc;
4952 			if (req->flags & TCP_LOG_HTTPD_RANGE_END)
4953 				fil->end_seq = (fil->start_seq + ((uint32_t)(fil->end - fil->start)));
4954 			else
4955 				fil->end_seq = 0;
4956 			if (tptosocket(tp)->so_snd.sb_tls_info) {
4957 				/*
4958 				 * This session is doing TLS. Take a swag guess
4959 				 * at the overhead.
4960 				 */
4961 				fil->end_seq += tcp_estimate_tls_overhead(
4962 				    tptosocket(tp), (fil->end - fil->start));
4963 			}
4964 			tp->t_tcpreq_req++;
4965 			if (fil->flags & TCP_TRK_TRACK_FLG_OPEN)
4966 				tp->t_tcpreq_open++;
4967 			else
4968 				tp->t_tcpreq_closed++;
4969 			tcp_req_log_req_info(tp, fil, i,
4970 			    TCP_TRK_REQ_LOG_NEW, 0, 0);
4971 			break;
4972 		} else
4973 			fil = NULL;
4974 	}
4975 	return (fil);
4976 }
4977 
4978 void
4979 tcp_req_alloc_req(struct tcpcb *tp, union tcp_log_userdata *user, uint64_t ts)
4980 {
4981 	(void)tcp_req_alloc_req_full(tp, &user->tcp_req, ts, 1);
4982 }
4983 #endif
4984 
4985 void
4986 tcp_log_socket_option(struct tcpcb *tp, uint32_t option_num, uint32_t option_val, int err)
4987 {
4988 	if (tcp_bblogging_on(tp)) {
4989 		struct tcp_log_buffer *l;
4990 
4991 		l = tcp_log_event(tp, NULL,
4992 		        &tptosocket(tp)->so_rcv,
4993 		        &tptosocket(tp)->so_snd,
4994 		        TCP_LOG_SOCKET_OPT,
4995 		        err, 0, NULL, 1,
4996 		        NULL, NULL, 0, NULL);
4997 		if (l) {
4998 			l->tlb_flex1 = option_num;
4999 			l->tlb_flex2 = option_val;
5000 		}
5001 	}
5002 }
5003 
5004 uint32_t
5005 tcp_get_srtt(struct tcpcb *tp, int granularity)
5006 {
5007 	uint32_t srtt;
5008 
5009 	KASSERT(granularity == TCP_TMR_GRANULARITY_USEC ||
5010 	    granularity == TCP_TMR_GRANULARITY_TICKS,
5011 	    ("%s: called with unexpected granularity %d", __func__,
5012 	    granularity));
5013 
5014 	srtt = tp->t_srtt;
5015 
5016 	/*
5017 	 * We only support two granularities. If the stored granularity
5018 	 * does not match the granularity requested by the caller,
5019 	 * convert the stored value to the requested unit of granularity.
5020 	 */
5021 	if (tp->t_tmr_granularity != granularity) {
5022 		if (granularity == TCP_TMR_GRANULARITY_USEC)
5023 			srtt = TICKS_2_USEC(srtt);
5024 		else
5025 			srtt = USEC_2_TICKS(srtt);
5026 	}
5027 
5028 	/*
5029 	 * If the srtt is stored with ticks granularity, we need to
5030 	 * unshift to get the actual value. We do this after the
5031 	 * conversion above (if one was necessary) in order to maximize
5032 	 * precision.
5033 	 */
5034 	if (tp->t_tmr_granularity == TCP_TMR_GRANULARITY_TICKS)
5035 		srtt = srtt >> TCP_RTT_SHIFT;
5036 
5037 	return (srtt);
5038 }
5039 
5040 void
5041 tcp_account_for_send(struct tcpcb *tp, uint32_t len, uint8_t is_rxt,
5042     uint8_t is_tlp, bool hw_tls)
5043 {
5044 
5045 	if (is_tlp) {
5046 		tp->t_sndtlppack++;
5047 		tp->t_sndtlpbyte += len;
5048 	}
5049 	/* To get total bytes sent you must add t_snd_rxt_bytes to t_sndbytes */
5050 	if (is_rxt)
5051 		tp->t_snd_rxt_bytes += len;
5052 	else
5053 		tp->t_sndbytes += len;
5054 
5055 #ifdef KERN_TLS
5056 	if (hw_tls && is_rxt && len != 0) {
5057 		uint64_t rexmit_percent;
5058 
5059 		rexmit_percent = (1000ULL * tp->t_snd_rxt_bytes) /
5060 		    (10ULL * (tp->t_snd_rxt_bytes + tp->t_sndbytes));
5061 		if (rexmit_percent > ktls_ifnet_max_rexmit_pct)
5062 			ktls_disable_ifnet(tp);
5063 	}
5064 #endif
5065 }
5066