xref: /freebsd/sys/netinet/tcp_usrreq.c (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1988, 1993
5  *	The Regents of the University of California.
6  * Copyright (c) 2006-2007 Robert N. M. Watson
7  * Copyright (c) 2010-2011 Juniper Networks, Inc.
8  * All rights reserved.
9  *
10  * Portions of this software were developed by Robert N. M. Watson under
11  * contract to Juniper Networks, Inc.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  *	From: @(#)tcp_usrreq.c	8.2 (Berkeley) 1/3/94
38  */
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include "opt_ddb.h"
44 #include "opt_inet.h"
45 #include "opt_inet6.h"
46 #include "opt_ipsec.h"
47 #include "opt_tcpdebug.h"
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/limits.h>
52 #include <sys/malloc.h>
53 #include <sys/refcount.h>
54 #include <sys/kernel.h>
55 #include <sys/sysctl.h>
56 #include <sys/mbuf.h>
57 #ifdef INET6
58 #include <sys/domain.h>
59 #endif /* INET6 */
60 #include <sys/socket.h>
61 #include <sys/socketvar.h>
62 #include <sys/protosw.h>
63 #include <sys/proc.h>
64 #include <sys/jail.h>
65 #include <sys/syslog.h>
66 
67 #ifdef DDB
68 #include <ddb/ddb.h>
69 #endif
70 
71 #include <net/if.h>
72 #include <net/if_var.h>
73 #include <net/route.h>
74 #include <net/vnet.h>
75 
76 #include <netinet/in.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_var.h>
82 #ifdef INET6
83 #include <netinet/ip6.h>
84 #include <netinet6/in6_pcb.h>
85 #include <netinet6/ip6_var.h>
86 #include <netinet6/scope6_var.h>
87 #endif
88 #ifdef TCP_RFC7413
89 #include <netinet/tcp_fastopen.h>
90 #endif
91 #include <netinet/tcp.h>
92 #include <netinet/tcp_fsm.h>
93 #include <netinet/tcp_seq.h>
94 #include <netinet/tcp_timer.h>
95 #include <netinet/tcp_var.h>
96 #include <netinet/tcpip.h>
97 #include <netinet/cc/cc.h>
98 #ifdef TCPPCAP
99 #include <netinet/tcp_pcap.h>
100 #endif
101 #ifdef TCPDEBUG
102 #include <netinet/tcp_debug.h>
103 #endif
104 #ifdef TCP_OFFLOAD
105 #include <netinet/tcp_offload.h>
106 #endif
107 #include <netipsec/ipsec_support.h>
108 
109 /*
110  * TCP protocol interface to socket abstraction.
111  */
112 static int	tcp_attach(struct socket *);
113 #ifdef INET
114 static int	tcp_connect(struct tcpcb *, struct sockaddr *,
115 		    struct thread *td);
116 #endif /* INET */
117 #ifdef INET6
118 static int	tcp6_connect(struct tcpcb *, struct sockaddr *,
119 		    struct thread *td);
120 #endif /* INET6 */
121 static void	tcp_disconnect(struct tcpcb *);
122 static void	tcp_usrclosed(struct tcpcb *);
123 static void	tcp_fill_info(struct tcpcb *, struct tcp_info *);
124 
125 #ifdef TCPDEBUG
126 #define	TCPDEBUG0	int ostate = 0
127 #define	TCPDEBUG1()	ostate = tp ? tp->t_state : 0
128 #define	TCPDEBUG2(req)	if (tp && (so->so_options & SO_DEBUG)) \
129 				tcp_trace(TA_USER, ostate, tp, 0, 0, req)
130 #else
131 #define	TCPDEBUG0
132 #define	TCPDEBUG1()
133 #define	TCPDEBUG2(req)
134 #endif
135 
136 /*
137  * TCP attaches to socket via pru_attach(), reserving space,
138  * and an internet control block.
139  */
140 static int
141 tcp_usr_attach(struct socket *so, int proto, struct thread *td)
142 {
143 	struct inpcb *inp;
144 	struct tcpcb *tp = NULL;
145 	int error;
146 	TCPDEBUG0;
147 
148 	inp = sotoinpcb(so);
149 	KASSERT(inp == NULL, ("tcp_usr_attach: inp != NULL"));
150 	TCPDEBUG1();
151 
152 	error = tcp_attach(so);
153 	if (error)
154 		goto out;
155 
156 	if ((so->so_options & SO_LINGER) && so->so_linger == 0)
157 		so->so_linger = TCP_LINGERTIME;
158 
159 	inp = sotoinpcb(so);
160 	tp = intotcpcb(inp);
161 out:
162 	TCPDEBUG2(PRU_ATTACH);
163 	TCP_PROBE2(debug__user, tp, PRU_ATTACH);
164 	return error;
165 }
166 
167 /*
168  * tcp_detach is called when the socket layer loses its final reference
169  * to the socket, be it a file descriptor reference, a reference from TCP,
170  * etc.  At this point, there is only one case in which we will keep around
171  * inpcb state: time wait.
172  *
173  * This function can probably be re-absorbed back into tcp_usr_detach() now
174  * that there is a single detach path.
175  */
176 static void
177 tcp_detach(struct socket *so, struct inpcb *inp)
178 {
179 	struct tcpcb *tp;
180 
181 	INP_INFO_LOCK_ASSERT(&V_tcbinfo);
182 	INP_WLOCK_ASSERT(inp);
183 
184 	KASSERT(so->so_pcb == inp, ("tcp_detach: so_pcb != inp"));
185 	KASSERT(inp->inp_socket == so, ("tcp_detach: inp_socket != so"));
186 
187 	tp = intotcpcb(inp);
188 
189 	if (inp->inp_flags & INP_TIMEWAIT) {
190 		/*
191 		 * There are two cases to handle: one in which the time wait
192 		 * state is being discarded (INP_DROPPED), and one in which
193 		 * this connection will remain in timewait.  In the former,
194 		 * it is time to discard all state (except tcptw, which has
195 		 * already been discarded by the timewait close code, which
196 		 * should be further up the call stack somewhere).  In the
197 		 * latter case, we detach from the socket, but leave the pcb
198 		 * present until timewait ends.
199 		 *
200 		 * XXXRW: Would it be cleaner to free the tcptw here?
201 		 *
202 		 * Astute question indeed, from twtcp perspective there are
203 		 * three cases to consider:
204 		 *
205 		 * #1 tcp_detach is called at tcptw creation time by
206 		 *  tcp_twstart, then do not discard the newly created tcptw
207 		 *  and leave inpcb present until timewait ends
208 		 * #2 tcp_detach is called at timewait end (or reuse) by
209 		 *  tcp_twclose, then the tcptw has already been discarded
210 		 *  (or reused) and inpcb is freed here
211 		 * #3 tcp_detach is called() after timewait ends (or reuse)
212 		 *  (e.g. by soclose), then tcptw has already been discarded
213 		 *  (or reused) and inpcb is freed here
214 		 *
215 		 *  In all three cases the tcptw should not be freed here.
216 		 */
217 		if (inp->inp_flags & INP_DROPPED) {
218 			in_pcbdetach(inp);
219 			if (__predict_true(tp == NULL)) {
220 				in_pcbfree(inp);
221 			} else {
222 				/*
223 				 * This case should not happen as in TIMEWAIT
224 				 * state the inp should not be destroyed before
225 				 * its tcptw.  If INVARIANTS is defined, panic.
226 				 */
227 #ifdef INVARIANTS
228 				panic("%s: Panic before an inp double-free: "
229 				    "INP_TIMEWAIT && INP_DROPPED && tp != NULL"
230 				    , __func__);
231 #else
232 				log(LOG_ERR, "%s: Avoid an inp double-free: "
233 				    "INP_TIMEWAIT && INP_DROPPED && tp != NULL"
234 				    , __func__);
235 #endif
236 				INP_WUNLOCK(inp);
237 			}
238 		} else {
239 			in_pcbdetach(inp);
240 			INP_WUNLOCK(inp);
241 		}
242 	} else {
243 		/*
244 		 * If the connection is not in timewait, we consider two
245 		 * two conditions: one in which no further processing is
246 		 * necessary (dropped || embryonic), and one in which TCP is
247 		 * not yet done, but no longer requires the socket, so the
248 		 * pcb will persist for the time being.
249 		 *
250 		 * XXXRW: Does the second case still occur?
251 		 */
252 		if (inp->inp_flags & INP_DROPPED ||
253 		    tp->t_state < TCPS_SYN_SENT) {
254 			tcp_discardcb(tp);
255 			in_pcbdetach(inp);
256 			in_pcbfree(inp);
257 		} else {
258 			in_pcbdetach(inp);
259 			INP_WUNLOCK(inp);
260 		}
261 	}
262 }
263 
264 /*
265  * pru_detach() detaches the TCP protocol from the socket.
266  * If the protocol state is non-embryonic, then can't
267  * do this directly: have to initiate a pru_disconnect(),
268  * which may finish later; embryonic TCB's can just
269  * be discarded here.
270  */
271 static void
272 tcp_usr_detach(struct socket *so)
273 {
274 	struct inpcb *inp;
275 	int rlock = 0;
276 
277 	inp = sotoinpcb(so);
278 	KASSERT(inp != NULL, ("tcp_usr_detach: inp == NULL"));
279 	if (!INP_INFO_WLOCKED(&V_tcbinfo)) {
280 		INP_INFO_RLOCK(&V_tcbinfo);
281 		rlock = 1;
282 	}
283 	INP_WLOCK(inp);
284 	KASSERT(inp->inp_socket != NULL,
285 	    ("tcp_usr_detach: inp_socket == NULL"));
286 	tcp_detach(so, inp);
287 	if (rlock)
288 		INP_INFO_RUNLOCK(&V_tcbinfo);
289 }
290 
291 #ifdef INET
292 /*
293  * Give the socket an address.
294  */
295 static int
296 tcp_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
297 {
298 	int error = 0;
299 	struct inpcb *inp;
300 	struct tcpcb *tp = NULL;
301 	struct sockaddr_in *sinp;
302 
303 	sinp = (struct sockaddr_in *)nam;
304 	if (nam->sa_len != sizeof (*sinp))
305 		return (EINVAL);
306 	/*
307 	 * Must check for multicast addresses and disallow binding
308 	 * to them.
309 	 */
310 	if (sinp->sin_family == AF_INET &&
311 	    IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
312 		return (EAFNOSUPPORT);
313 
314 	TCPDEBUG0;
315 	inp = sotoinpcb(so);
316 	KASSERT(inp != NULL, ("tcp_usr_bind: inp == NULL"));
317 	INP_WLOCK(inp);
318 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
319 		error = EINVAL;
320 		goto out;
321 	}
322 	tp = intotcpcb(inp);
323 	TCPDEBUG1();
324 	INP_HASH_WLOCK(&V_tcbinfo);
325 	error = in_pcbbind(inp, nam, td->td_ucred);
326 	INP_HASH_WUNLOCK(&V_tcbinfo);
327 out:
328 	TCPDEBUG2(PRU_BIND);
329 	TCP_PROBE2(debug__user, tp, PRU_BIND);
330 	INP_WUNLOCK(inp);
331 
332 	return (error);
333 }
334 #endif /* INET */
335 
336 #ifdef INET6
337 static int
338 tcp6_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
339 {
340 	int error = 0;
341 	struct inpcb *inp;
342 	struct tcpcb *tp = NULL;
343 	struct sockaddr_in6 *sin6p;
344 
345 	sin6p = (struct sockaddr_in6 *)nam;
346 	if (nam->sa_len != sizeof (*sin6p))
347 		return (EINVAL);
348 	/*
349 	 * Must check for multicast addresses and disallow binding
350 	 * to them.
351 	 */
352 	if (sin6p->sin6_family == AF_INET6 &&
353 	    IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
354 		return (EAFNOSUPPORT);
355 
356 	TCPDEBUG0;
357 	inp = sotoinpcb(so);
358 	KASSERT(inp != NULL, ("tcp6_usr_bind: inp == NULL"));
359 	INP_WLOCK(inp);
360 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
361 		error = EINVAL;
362 		goto out;
363 	}
364 	tp = intotcpcb(inp);
365 	TCPDEBUG1();
366 	INP_HASH_WLOCK(&V_tcbinfo);
367 	inp->inp_vflag &= ~INP_IPV4;
368 	inp->inp_vflag |= INP_IPV6;
369 #ifdef INET
370 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
371 		if (IN6_IS_ADDR_UNSPECIFIED(&sin6p->sin6_addr))
372 			inp->inp_vflag |= INP_IPV4;
373 		else if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
374 			struct sockaddr_in sin;
375 
376 			in6_sin6_2_sin(&sin, sin6p);
377 			inp->inp_vflag |= INP_IPV4;
378 			inp->inp_vflag &= ~INP_IPV6;
379 			error = in_pcbbind(inp, (struct sockaddr *)&sin,
380 			    td->td_ucred);
381 			INP_HASH_WUNLOCK(&V_tcbinfo);
382 			goto out;
383 		}
384 	}
385 #endif
386 	error = in6_pcbbind(inp, nam, td->td_ucred);
387 	INP_HASH_WUNLOCK(&V_tcbinfo);
388 out:
389 	TCPDEBUG2(PRU_BIND);
390 	TCP_PROBE2(debug__user, tp, PRU_BIND);
391 	INP_WUNLOCK(inp);
392 	return (error);
393 }
394 #endif /* INET6 */
395 
396 #ifdef INET
397 /*
398  * Prepare to accept connections.
399  */
400 static int
401 tcp_usr_listen(struct socket *so, int backlog, struct thread *td)
402 {
403 	int error = 0;
404 	struct inpcb *inp;
405 	struct tcpcb *tp = NULL;
406 
407 	TCPDEBUG0;
408 	inp = sotoinpcb(so);
409 	KASSERT(inp != NULL, ("tcp_usr_listen: inp == NULL"));
410 	INP_WLOCK(inp);
411 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
412 		error = EINVAL;
413 		goto out;
414 	}
415 	tp = intotcpcb(inp);
416 	TCPDEBUG1();
417 	SOCK_LOCK(so);
418 	error = solisten_proto_check(so);
419 	INP_HASH_WLOCK(&V_tcbinfo);
420 	if (error == 0 && inp->inp_lport == 0)
421 		error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
422 	INP_HASH_WUNLOCK(&V_tcbinfo);
423 	if (error == 0) {
424 		tcp_state_change(tp, TCPS_LISTEN);
425 		solisten_proto(so, backlog);
426 #ifdef TCP_OFFLOAD
427 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
428 			tcp_offload_listen_start(tp);
429 #endif
430 	}
431 	SOCK_UNLOCK(so);
432 
433 #ifdef TCP_RFC7413
434 	if (IS_FASTOPEN(tp->t_flags))
435 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
436 #endif
437 out:
438 	TCPDEBUG2(PRU_LISTEN);
439 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
440 	INP_WUNLOCK(inp);
441 	return (error);
442 }
443 #endif /* INET */
444 
445 #ifdef INET6
446 static int
447 tcp6_usr_listen(struct socket *so, int backlog, struct thread *td)
448 {
449 	int error = 0;
450 	struct inpcb *inp;
451 	struct tcpcb *tp = NULL;
452 
453 	TCPDEBUG0;
454 	inp = sotoinpcb(so);
455 	KASSERT(inp != NULL, ("tcp6_usr_listen: inp == NULL"));
456 	INP_WLOCK(inp);
457 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
458 		error = EINVAL;
459 		goto out;
460 	}
461 	tp = intotcpcb(inp);
462 	TCPDEBUG1();
463 	SOCK_LOCK(so);
464 	error = solisten_proto_check(so);
465 	INP_HASH_WLOCK(&V_tcbinfo);
466 	if (error == 0 && inp->inp_lport == 0) {
467 		inp->inp_vflag &= ~INP_IPV4;
468 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
469 			inp->inp_vflag |= INP_IPV4;
470 		error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
471 	}
472 	INP_HASH_WUNLOCK(&V_tcbinfo);
473 	if (error == 0) {
474 		tcp_state_change(tp, TCPS_LISTEN);
475 		solisten_proto(so, backlog);
476 #ifdef TCP_OFFLOAD
477 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
478 			tcp_offload_listen_start(tp);
479 #endif
480 	}
481 	SOCK_UNLOCK(so);
482 
483 #ifdef TCP_RFC7413
484 	if (IS_FASTOPEN(tp->t_flags))
485 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
486 #endif
487 out:
488 	TCPDEBUG2(PRU_LISTEN);
489 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
490 	INP_WUNLOCK(inp);
491 	return (error);
492 }
493 #endif /* INET6 */
494 
495 #ifdef INET
496 /*
497  * Initiate connection to peer.
498  * Create a template for use in transmissions on this connection.
499  * Enter SYN_SENT state, and mark socket as connecting.
500  * Start keep-alive timer, and seed output sequence space.
501  * Send initial segment on connection.
502  */
503 static int
504 tcp_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
505 {
506 	int error = 0;
507 	struct inpcb *inp;
508 	struct tcpcb *tp = NULL;
509 	struct sockaddr_in *sinp;
510 
511 	sinp = (struct sockaddr_in *)nam;
512 	if (nam->sa_len != sizeof (*sinp))
513 		return (EINVAL);
514 	/*
515 	 * Must disallow TCP ``connections'' to multicast addresses.
516 	 */
517 	if (sinp->sin_family == AF_INET
518 	    && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
519 		return (EAFNOSUPPORT);
520 	if ((error = prison_remote_ip4(td->td_ucred, &sinp->sin_addr)) != 0)
521 		return (error);
522 
523 	TCPDEBUG0;
524 	inp = sotoinpcb(so);
525 	KASSERT(inp != NULL, ("tcp_usr_connect: inp == NULL"));
526 	INP_WLOCK(inp);
527 	if (inp->inp_flags & INP_TIMEWAIT) {
528 		error = EADDRINUSE;
529 		goto out;
530 	}
531 	if (inp->inp_flags & INP_DROPPED) {
532 		error = ECONNREFUSED;
533 		goto out;
534 	}
535 	tp = intotcpcb(inp);
536 	TCPDEBUG1();
537 	if ((error = tcp_connect(tp, nam, td)) != 0)
538 		goto out;
539 #ifdef TCP_OFFLOAD
540 	if (registered_toedevs > 0 &&
541 	    (so->so_options & SO_NO_OFFLOAD) == 0 &&
542 	    (error = tcp_offload_connect(so, nam)) == 0)
543 		goto out;
544 #endif
545 	tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
546 	error = tp->t_fb->tfb_tcp_output(tp);
547 out:
548 	TCPDEBUG2(PRU_CONNECT);
549 	TCP_PROBE2(debug__user, tp, PRU_CONNECT);
550 	INP_WUNLOCK(inp);
551 	return (error);
552 }
553 #endif /* INET */
554 
555 #ifdef INET6
556 static int
557 tcp6_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
558 {
559 	int error = 0;
560 	struct inpcb *inp;
561 	struct tcpcb *tp = NULL;
562 	struct sockaddr_in6 *sin6p;
563 
564 	TCPDEBUG0;
565 
566 	sin6p = (struct sockaddr_in6 *)nam;
567 	if (nam->sa_len != sizeof (*sin6p))
568 		return (EINVAL);
569 	/*
570 	 * Must disallow TCP ``connections'' to multicast addresses.
571 	 */
572 	if (sin6p->sin6_family == AF_INET6
573 	    && IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
574 		return (EAFNOSUPPORT);
575 
576 	inp = sotoinpcb(so);
577 	KASSERT(inp != NULL, ("tcp6_usr_connect: inp == NULL"));
578 	INP_WLOCK(inp);
579 	if (inp->inp_flags & INP_TIMEWAIT) {
580 		error = EADDRINUSE;
581 		goto out;
582 	}
583 	if (inp->inp_flags & INP_DROPPED) {
584 		error = ECONNREFUSED;
585 		goto out;
586 	}
587 	tp = intotcpcb(inp);
588 	TCPDEBUG1();
589 #ifdef INET
590 	/*
591 	 * XXXRW: Some confusion: V4/V6 flags relate to binding, and
592 	 * therefore probably require the hash lock, which isn't held here.
593 	 * Is this a significant problem?
594 	 */
595 	if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
596 		struct sockaddr_in sin;
597 
598 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
599 			error = EINVAL;
600 			goto out;
601 		}
602 		if ((inp->inp_vflag & INP_IPV4) == 0) {
603 			error = EAFNOSUPPORT;
604 			goto out;
605 		}
606 
607 		in6_sin6_2_sin(&sin, sin6p);
608 		inp->inp_vflag |= INP_IPV4;
609 		inp->inp_vflag &= ~INP_IPV6;
610 		if ((error = prison_remote_ip4(td->td_ucred,
611 		    &sin.sin_addr)) != 0)
612 			goto out;
613 		if ((error = tcp_connect(tp, (struct sockaddr *)&sin, td)) != 0)
614 			goto out;
615 #ifdef TCP_OFFLOAD
616 		if (registered_toedevs > 0 &&
617 		    (so->so_options & SO_NO_OFFLOAD) == 0 &&
618 		    (error = tcp_offload_connect(so, nam)) == 0)
619 			goto out;
620 #endif
621 		error = tp->t_fb->tfb_tcp_output(tp);
622 		goto out;
623 	} else {
624 		if ((inp->inp_vflag & INP_IPV6) == 0) {
625 			error = EAFNOSUPPORT;
626 			goto out;
627 		}
628 	}
629 #endif
630 	inp->inp_vflag &= ~INP_IPV4;
631 	inp->inp_vflag |= INP_IPV6;
632 	inp->inp_inc.inc_flags |= INC_ISIPV6;
633 	if ((error = prison_remote_ip6(td->td_ucred, &sin6p->sin6_addr)) != 0)
634 		goto out;
635 	if ((error = tcp6_connect(tp, nam, td)) != 0)
636 		goto out;
637 #ifdef TCP_OFFLOAD
638 	if (registered_toedevs > 0 &&
639 	    (so->so_options & SO_NO_OFFLOAD) == 0 &&
640 	    (error = tcp_offload_connect(so, nam)) == 0)
641 		goto out;
642 #endif
643 	tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
644 	error = tp->t_fb->tfb_tcp_output(tp);
645 
646 out:
647 	TCPDEBUG2(PRU_CONNECT);
648 	TCP_PROBE2(debug__user, tp, PRU_CONNECT);
649 	INP_WUNLOCK(inp);
650 	return (error);
651 }
652 #endif /* INET6 */
653 
654 /*
655  * Initiate disconnect from peer.
656  * If connection never passed embryonic stage, just drop;
657  * else if don't need to let data drain, then can just drop anyways,
658  * else have to begin TCP shutdown process: mark socket disconnecting,
659  * drain unread data, state switch to reflect user close, and
660  * send segment (e.g. FIN) to peer.  Socket will be really disconnected
661  * when peer sends FIN and acks ours.
662  *
663  * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
664  */
665 static int
666 tcp_usr_disconnect(struct socket *so)
667 {
668 	struct inpcb *inp;
669 	struct tcpcb *tp = NULL;
670 	int error = 0;
671 
672 	TCPDEBUG0;
673 	INP_INFO_RLOCK(&V_tcbinfo);
674 	inp = sotoinpcb(so);
675 	KASSERT(inp != NULL, ("tcp_usr_disconnect: inp == NULL"));
676 	INP_WLOCK(inp);
677 	if (inp->inp_flags & INP_TIMEWAIT)
678 		goto out;
679 	if (inp->inp_flags & INP_DROPPED) {
680 		error = ECONNRESET;
681 		goto out;
682 	}
683 	tp = intotcpcb(inp);
684 	TCPDEBUG1();
685 	tcp_disconnect(tp);
686 out:
687 	TCPDEBUG2(PRU_DISCONNECT);
688 	TCP_PROBE2(debug__user, tp, PRU_DISCONNECT);
689 	INP_WUNLOCK(inp);
690 	INP_INFO_RUNLOCK(&V_tcbinfo);
691 	return (error);
692 }
693 
694 #ifdef INET
695 /*
696  * Accept a connection.  Essentially all the work is done at higher levels;
697  * just return the address of the peer, storing through addr.
698  */
699 static int
700 tcp_usr_accept(struct socket *so, struct sockaddr **nam)
701 {
702 	int error = 0;
703 	struct inpcb *inp = NULL;
704 	struct tcpcb *tp = NULL;
705 	struct in_addr addr;
706 	in_port_t port = 0;
707 	TCPDEBUG0;
708 
709 	if (so->so_state & SS_ISDISCONNECTED)
710 		return (ECONNABORTED);
711 
712 	inp = sotoinpcb(so);
713 	KASSERT(inp != NULL, ("tcp_usr_accept: inp == NULL"));
714 	INP_WLOCK(inp);
715 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
716 		error = ECONNABORTED;
717 		goto out;
718 	}
719 	tp = intotcpcb(inp);
720 	TCPDEBUG1();
721 
722 	/*
723 	 * We inline in_getpeeraddr and COMMON_END here, so that we can
724 	 * copy the data of interest and defer the malloc until after we
725 	 * release the lock.
726 	 */
727 	port = inp->inp_fport;
728 	addr = inp->inp_faddr;
729 
730 out:
731 	TCPDEBUG2(PRU_ACCEPT);
732 	TCP_PROBE2(debug__user, tp, PRU_ACCEPT);
733 	INP_WUNLOCK(inp);
734 	if (error == 0)
735 		*nam = in_sockaddr(port, &addr);
736 	return error;
737 }
738 #endif /* INET */
739 
740 #ifdef INET6
741 static int
742 tcp6_usr_accept(struct socket *so, struct sockaddr **nam)
743 {
744 	struct inpcb *inp = NULL;
745 	int error = 0;
746 	struct tcpcb *tp = NULL;
747 	struct in_addr addr;
748 	struct in6_addr addr6;
749 	in_port_t port = 0;
750 	int v4 = 0;
751 	TCPDEBUG0;
752 
753 	if (so->so_state & SS_ISDISCONNECTED)
754 		return (ECONNABORTED);
755 
756 	inp = sotoinpcb(so);
757 	KASSERT(inp != NULL, ("tcp6_usr_accept: inp == NULL"));
758 	INP_INFO_RLOCK(&V_tcbinfo);
759 	INP_WLOCK(inp);
760 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
761 		error = ECONNABORTED;
762 		goto out;
763 	}
764 	tp = intotcpcb(inp);
765 	TCPDEBUG1();
766 
767 	/*
768 	 * We inline in6_mapped_peeraddr and COMMON_END here, so that we can
769 	 * copy the data of interest and defer the malloc until after we
770 	 * release the lock.
771 	 */
772 	if (inp->inp_vflag & INP_IPV4) {
773 		v4 = 1;
774 		port = inp->inp_fport;
775 		addr = inp->inp_faddr;
776 	} else {
777 		port = inp->inp_fport;
778 		addr6 = inp->in6p_faddr;
779 	}
780 
781 out:
782 	TCPDEBUG2(PRU_ACCEPT);
783 	TCP_PROBE2(debug__user, tp, PRU_ACCEPT);
784 	INP_WUNLOCK(inp);
785 	INP_INFO_RUNLOCK(&V_tcbinfo);
786 	if (error == 0) {
787 		if (v4)
788 			*nam = in6_v4mapsin6_sockaddr(port, &addr);
789 		else
790 			*nam = in6_sockaddr(port, &addr6);
791 	}
792 	return error;
793 }
794 #endif /* INET6 */
795 
796 /*
797  * Mark the connection as being incapable of further output.
798  */
799 static int
800 tcp_usr_shutdown(struct socket *so)
801 {
802 	int error = 0;
803 	struct inpcb *inp;
804 	struct tcpcb *tp = NULL;
805 
806 	TCPDEBUG0;
807 	INP_INFO_RLOCK(&V_tcbinfo);
808 	inp = sotoinpcb(so);
809 	KASSERT(inp != NULL, ("inp == NULL"));
810 	INP_WLOCK(inp);
811 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
812 		error = ECONNRESET;
813 		goto out;
814 	}
815 	tp = intotcpcb(inp);
816 	TCPDEBUG1();
817 	socantsendmore(so);
818 	tcp_usrclosed(tp);
819 	if (!(inp->inp_flags & INP_DROPPED))
820 		error = tp->t_fb->tfb_tcp_output(tp);
821 
822 out:
823 	TCPDEBUG2(PRU_SHUTDOWN);
824 	TCP_PROBE2(debug__user, tp, PRU_SHUTDOWN);
825 	INP_WUNLOCK(inp);
826 	INP_INFO_RUNLOCK(&V_tcbinfo);
827 
828 	return (error);
829 }
830 
831 /*
832  * After a receive, possibly send window update to peer.
833  */
834 static int
835 tcp_usr_rcvd(struct socket *so, int flags)
836 {
837 	struct inpcb *inp;
838 	struct tcpcb *tp = NULL;
839 	int error = 0;
840 
841 	TCPDEBUG0;
842 	inp = sotoinpcb(so);
843 	KASSERT(inp != NULL, ("tcp_usr_rcvd: inp == NULL"));
844 	INP_WLOCK(inp);
845 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
846 		error = ECONNRESET;
847 		goto out;
848 	}
849 	tp = intotcpcb(inp);
850 	TCPDEBUG1();
851 #ifdef TCP_RFC7413
852 	/*
853 	 * For passively-created TFO connections, don't attempt a window
854 	 * update while still in SYN_RECEIVED as this may trigger an early
855 	 * SYN|ACK.  It is preferable to have the SYN|ACK be sent along with
856 	 * application response data, or failing that, when the DELACK timer
857 	 * expires.
858 	 */
859 	if (IS_FASTOPEN(tp->t_flags) &&
860 	    (tp->t_state == TCPS_SYN_RECEIVED))
861 		goto out;
862 #endif
863 #ifdef TCP_OFFLOAD
864 	if (tp->t_flags & TF_TOE)
865 		tcp_offload_rcvd(tp);
866 	else
867 #endif
868 	tp->t_fb->tfb_tcp_output(tp);
869 
870 out:
871 	TCPDEBUG2(PRU_RCVD);
872 	TCP_PROBE2(debug__user, tp, PRU_RCVD);
873 	INP_WUNLOCK(inp);
874 	return (error);
875 }
876 
877 /*
878  * Do a send by putting data in output queue and updating urgent
879  * marker if URG set.  Possibly send more data.  Unlike the other
880  * pru_*() routines, the mbuf chains are our responsibility.  We
881  * must either enqueue them or free them.  The other pru_* routines
882  * generally are caller-frees.
883  */
884 static int
885 tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
886     struct sockaddr *nam, struct mbuf *control, struct thread *td)
887 {
888 	int error = 0;
889 	struct inpcb *inp;
890 	struct tcpcb *tp = NULL;
891 #ifdef INET6
892 	int isipv6;
893 #endif
894 	TCPDEBUG0;
895 
896 	/*
897 	 * We require the pcbinfo lock if we will close the socket as part of
898 	 * this call.
899 	 */
900 	if (flags & PRUS_EOF)
901 		INP_INFO_RLOCK(&V_tcbinfo);
902 	inp = sotoinpcb(so);
903 	KASSERT(inp != NULL, ("tcp_usr_send: inp == NULL"));
904 	INP_WLOCK(inp);
905 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
906 		if (control)
907 			m_freem(control);
908 		/*
909 		 * In case of PRUS_NOTREADY, tcp_usr_ready() is responsible
910 		 * for freeing memory.
911 		 */
912 		if (m && (flags & PRUS_NOTREADY) == 0)
913 			m_freem(m);
914 		error = ECONNRESET;
915 		goto out;
916 	}
917 #ifdef INET6
918 	isipv6 = nam && nam->sa_family == AF_INET6;
919 #endif /* INET6 */
920 	tp = intotcpcb(inp);
921 	TCPDEBUG1();
922 	if (control) {
923 		/* TCP doesn't do control messages (rights, creds, etc) */
924 		if (control->m_len) {
925 			m_freem(control);
926 			if (m)
927 				m_freem(m);
928 			error = EINVAL;
929 			goto out;
930 		}
931 		m_freem(control);	/* empty control, just free it */
932 	}
933 	if (!(flags & PRUS_OOB)) {
934 		sbappendstream(&so->so_snd, m, flags);
935 		if (nam && tp->t_state < TCPS_SYN_SENT) {
936 			/*
937 			 * Do implied connect if not yet connected,
938 			 * initialize window to default value, and
939 			 * initialize maxseg using peer's cached MSS.
940 			 */
941 #ifdef INET6
942 			if (isipv6)
943 				error = tcp6_connect(tp, nam, td);
944 #endif /* INET6 */
945 #if defined(INET6) && defined(INET)
946 			else
947 #endif
948 #ifdef INET
949 				error = tcp_connect(tp, nam, td);
950 #endif
951 			if (error)
952 				goto out;
953 			tp->snd_wnd = TTCP_CLIENT_SND_WND;
954 			tcp_mss(tp, -1);
955 		}
956 		if (flags & PRUS_EOF) {
957 			/*
958 			 * Close the send side of the connection after
959 			 * the data is sent.
960 			 */
961 			INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
962 			socantsendmore(so);
963 			tcp_usrclosed(tp);
964 		}
965 		if (!(inp->inp_flags & INP_DROPPED) &&
966 		    !(flags & PRUS_NOTREADY)) {
967 			if (flags & PRUS_MORETOCOME)
968 				tp->t_flags |= TF_MORETOCOME;
969 			error = tp->t_fb->tfb_tcp_output(tp);
970 			if (flags & PRUS_MORETOCOME)
971 				tp->t_flags &= ~TF_MORETOCOME;
972 		}
973 	} else {
974 		/*
975 		 * XXXRW: PRUS_EOF not implemented with PRUS_OOB?
976 		 */
977 		SOCKBUF_LOCK(&so->so_snd);
978 		if (sbspace(&so->so_snd) < -512) {
979 			SOCKBUF_UNLOCK(&so->so_snd);
980 			m_freem(m);
981 			error = ENOBUFS;
982 			goto out;
983 		}
984 		/*
985 		 * According to RFC961 (Assigned Protocols),
986 		 * the urgent pointer points to the last octet
987 		 * of urgent data.  We continue, however,
988 		 * to consider it to indicate the first octet
989 		 * of data past the urgent section.
990 		 * Otherwise, snd_up should be one lower.
991 		 */
992 		sbappendstream_locked(&so->so_snd, m, flags);
993 		SOCKBUF_UNLOCK(&so->so_snd);
994 		if (nam && tp->t_state < TCPS_SYN_SENT) {
995 			/*
996 			 * Do implied connect if not yet connected,
997 			 * initialize window to default value, and
998 			 * initialize maxseg using peer's cached MSS.
999 			 */
1000 #ifdef INET6
1001 			if (isipv6)
1002 				error = tcp6_connect(tp, nam, td);
1003 #endif /* INET6 */
1004 #if defined(INET6) && defined(INET)
1005 			else
1006 #endif
1007 #ifdef INET
1008 				error = tcp_connect(tp, nam, td);
1009 #endif
1010 			if (error)
1011 				goto out;
1012 			tp->snd_wnd = TTCP_CLIENT_SND_WND;
1013 			tcp_mss(tp, -1);
1014 		}
1015 		tp->snd_up = tp->snd_una + sbavail(&so->so_snd);
1016 		if (!(flags & PRUS_NOTREADY)) {
1017 			tp->t_flags |= TF_FORCEDATA;
1018 			error = tp->t_fb->tfb_tcp_output(tp);
1019 			tp->t_flags &= ~TF_FORCEDATA;
1020 		}
1021 	}
1022 out:
1023 	TCPDEBUG2((flags & PRUS_OOB) ? PRU_SENDOOB :
1024 		  ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
1025 	TCP_PROBE2(debug__user, tp, (flags & PRUS_OOB) ? PRU_SENDOOB :
1026 		   ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
1027 	INP_WUNLOCK(inp);
1028 	if (flags & PRUS_EOF)
1029 		INP_INFO_RUNLOCK(&V_tcbinfo);
1030 	return (error);
1031 }
1032 
1033 static int
1034 tcp_usr_ready(struct socket *so, struct mbuf *m, int count)
1035 {
1036 	struct inpcb *inp;
1037 	struct tcpcb *tp;
1038 	int error;
1039 
1040 	inp = sotoinpcb(so);
1041 	INP_WLOCK(inp);
1042 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1043 		INP_WUNLOCK(inp);
1044 		for (int i = 0; i < count; i++)
1045 			m = m_free(m);
1046 		return (ECONNRESET);
1047 	}
1048 	tp = intotcpcb(inp);
1049 
1050 	SOCKBUF_LOCK(&so->so_snd);
1051 	error = sbready(&so->so_snd, m, count);
1052 	SOCKBUF_UNLOCK(&so->so_snd);
1053 	if (error == 0)
1054 		error = tp->t_fb->tfb_tcp_output(tp);
1055 	INP_WUNLOCK(inp);
1056 
1057 	return (error);
1058 }
1059 
1060 /*
1061  * Abort the TCP.  Drop the connection abruptly.
1062  */
1063 static void
1064 tcp_usr_abort(struct socket *so)
1065 {
1066 	struct inpcb *inp;
1067 	struct tcpcb *tp = NULL;
1068 	TCPDEBUG0;
1069 
1070 	inp = sotoinpcb(so);
1071 	KASSERT(inp != NULL, ("tcp_usr_abort: inp == NULL"));
1072 
1073 	INP_INFO_RLOCK(&V_tcbinfo);
1074 	INP_WLOCK(inp);
1075 	KASSERT(inp->inp_socket != NULL,
1076 	    ("tcp_usr_abort: inp_socket == NULL"));
1077 
1078 	/*
1079 	 * If we still have full TCP state, and we're not dropped, drop.
1080 	 */
1081 	if (!(inp->inp_flags & INP_TIMEWAIT) &&
1082 	    !(inp->inp_flags & INP_DROPPED)) {
1083 		tp = intotcpcb(inp);
1084 		TCPDEBUG1();
1085 		tcp_drop(tp, ECONNABORTED);
1086 		TCPDEBUG2(PRU_ABORT);
1087 		TCP_PROBE2(debug__user, tp, PRU_ABORT);
1088 	}
1089 	if (!(inp->inp_flags & INP_DROPPED)) {
1090 		SOCK_LOCK(so);
1091 		so->so_state |= SS_PROTOREF;
1092 		SOCK_UNLOCK(so);
1093 		inp->inp_flags |= INP_SOCKREF;
1094 	}
1095 	INP_WUNLOCK(inp);
1096 	INP_INFO_RUNLOCK(&V_tcbinfo);
1097 }
1098 
1099 /*
1100  * TCP socket is closed.  Start friendly disconnect.
1101  */
1102 static void
1103 tcp_usr_close(struct socket *so)
1104 {
1105 	struct inpcb *inp;
1106 	struct tcpcb *tp = NULL;
1107 	TCPDEBUG0;
1108 
1109 	inp = sotoinpcb(so);
1110 	KASSERT(inp != NULL, ("tcp_usr_close: inp == NULL"));
1111 
1112 	INP_INFO_RLOCK(&V_tcbinfo);
1113 	INP_WLOCK(inp);
1114 	KASSERT(inp->inp_socket != NULL,
1115 	    ("tcp_usr_close: inp_socket == NULL"));
1116 
1117 	/*
1118 	 * If we still have full TCP state, and we're not dropped, initiate
1119 	 * a disconnect.
1120 	 */
1121 	if (!(inp->inp_flags & INP_TIMEWAIT) &&
1122 	    !(inp->inp_flags & INP_DROPPED)) {
1123 		tp = intotcpcb(inp);
1124 		TCPDEBUG1();
1125 		tcp_disconnect(tp);
1126 		TCPDEBUG2(PRU_CLOSE);
1127 		TCP_PROBE2(debug__user, tp, PRU_CLOSE);
1128 	}
1129 	if (!(inp->inp_flags & INP_DROPPED)) {
1130 		SOCK_LOCK(so);
1131 		so->so_state |= SS_PROTOREF;
1132 		SOCK_UNLOCK(so);
1133 		inp->inp_flags |= INP_SOCKREF;
1134 	}
1135 	INP_WUNLOCK(inp);
1136 	INP_INFO_RUNLOCK(&V_tcbinfo);
1137 }
1138 
1139 /*
1140  * Receive out-of-band data.
1141  */
1142 static int
1143 tcp_usr_rcvoob(struct socket *so, struct mbuf *m, int flags)
1144 {
1145 	int error = 0;
1146 	struct inpcb *inp;
1147 	struct tcpcb *tp = NULL;
1148 
1149 	TCPDEBUG0;
1150 	inp = sotoinpcb(so);
1151 	KASSERT(inp != NULL, ("tcp_usr_rcvoob: inp == NULL"));
1152 	INP_WLOCK(inp);
1153 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1154 		error = ECONNRESET;
1155 		goto out;
1156 	}
1157 	tp = intotcpcb(inp);
1158 	TCPDEBUG1();
1159 	if ((so->so_oobmark == 0 &&
1160 	     (so->so_rcv.sb_state & SBS_RCVATMARK) == 0) ||
1161 	    so->so_options & SO_OOBINLINE ||
1162 	    tp->t_oobflags & TCPOOB_HADDATA) {
1163 		error = EINVAL;
1164 		goto out;
1165 	}
1166 	if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
1167 		error = EWOULDBLOCK;
1168 		goto out;
1169 	}
1170 	m->m_len = 1;
1171 	*mtod(m, caddr_t) = tp->t_iobc;
1172 	if ((flags & MSG_PEEK) == 0)
1173 		tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
1174 
1175 out:
1176 	TCPDEBUG2(PRU_RCVOOB);
1177 	TCP_PROBE2(debug__user, tp, PRU_RCVOOB);
1178 	INP_WUNLOCK(inp);
1179 	return (error);
1180 }
1181 
1182 #ifdef INET
1183 struct pr_usrreqs tcp_usrreqs = {
1184 	.pru_abort =		tcp_usr_abort,
1185 	.pru_accept =		tcp_usr_accept,
1186 	.pru_attach =		tcp_usr_attach,
1187 	.pru_bind =		tcp_usr_bind,
1188 	.pru_connect =		tcp_usr_connect,
1189 	.pru_control =		in_control,
1190 	.pru_detach =		tcp_usr_detach,
1191 	.pru_disconnect =	tcp_usr_disconnect,
1192 	.pru_listen =		tcp_usr_listen,
1193 	.pru_peeraddr =		in_getpeeraddr,
1194 	.pru_rcvd =		tcp_usr_rcvd,
1195 	.pru_rcvoob =		tcp_usr_rcvoob,
1196 	.pru_send =		tcp_usr_send,
1197 	.pru_ready =		tcp_usr_ready,
1198 	.pru_shutdown =		tcp_usr_shutdown,
1199 	.pru_sockaddr =		in_getsockaddr,
1200 	.pru_sosetlabel =	in_pcbsosetlabel,
1201 	.pru_close =		tcp_usr_close,
1202 };
1203 #endif /* INET */
1204 
1205 #ifdef INET6
1206 struct pr_usrreqs tcp6_usrreqs = {
1207 	.pru_abort =		tcp_usr_abort,
1208 	.pru_accept =		tcp6_usr_accept,
1209 	.pru_attach =		tcp_usr_attach,
1210 	.pru_bind =		tcp6_usr_bind,
1211 	.pru_connect =		tcp6_usr_connect,
1212 	.pru_control =		in6_control,
1213 	.pru_detach =		tcp_usr_detach,
1214 	.pru_disconnect =	tcp_usr_disconnect,
1215 	.pru_listen =		tcp6_usr_listen,
1216 	.pru_peeraddr =		in6_mapped_peeraddr,
1217 	.pru_rcvd =		tcp_usr_rcvd,
1218 	.pru_rcvoob =		tcp_usr_rcvoob,
1219 	.pru_send =		tcp_usr_send,
1220 	.pru_ready =		tcp_usr_ready,
1221 	.pru_shutdown =		tcp_usr_shutdown,
1222 	.pru_sockaddr =		in6_mapped_sockaddr,
1223 	.pru_sosetlabel =	in_pcbsosetlabel,
1224 	.pru_close =		tcp_usr_close,
1225 };
1226 #endif /* INET6 */
1227 
1228 #ifdef INET
1229 /*
1230  * Common subroutine to open a TCP connection to remote host specified
1231  * by struct sockaddr_in in mbuf *nam.  Call in_pcbbind to assign a local
1232  * port number if needed.  Call in_pcbconnect_setup to do the routing and
1233  * to choose a local host address (interface).  If there is an existing
1234  * incarnation of the same connection in TIME-WAIT state and if the remote
1235  * host was sending CC options and if the connection duration was < MSL, then
1236  * truncate the previous TIME-WAIT state and proceed.
1237  * Initialize connection parameters and enter SYN-SENT state.
1238  */
1239 static int
1240 tcp_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
1241 {
1242 	struct inpcb *inp = tp->t_inpcb, *oinp;
1243 	struct socket *so = inp->inp_socket;
1244 	struct in_addr laddr;
1245 	u_short lport;
1246 	int error;
1247 
1248 	INP_WLOCK_ASSERT(inp);
1249 	INP_HASH_WLOCK(&V_tcbinfo);
1250 
1251 	if (inp->inp_lport == 0) {
1252 		error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
1253 		if (error)
1254 			goto out;
1255 	}
1256 
1257 	/*
1258 	 * Cannot simply call in_pcbconnect, because there might be an
1259 	 * earlier incarnation of this same connection still in
1260 	 * TIME_WAIT state, creating an ADDRINUSE error.
1261 	 */
1262 	laddr = inp->inp_laddr;
1263 	lport = inp->inp_lport;
1264 	error = in_pcbconnect_setup(inp, nam, &laddr.s_addr, &lport,
1265 	    &inp->inp_faddr.s_addr, &inp->inp_fport, &oinp, td->td_ucred);
1266 	if (error && oinp == NULL)
1267 		goto out;
1268 	if (oinp) {
1269 		error = EADDRINUSE;
1270 		goto out;
1271 	}
1272 	inp->inp_laddr = laddr;
1273 	in_pcbrehash(inp);
1274 	INP_HASH_WUNLOCK(&V_tcbinfo);
1275 
1276 	/*
1277 	 * Compute window scaling to request:
1278 	 * Scale to fit into sweet spot.  See tcp_syncache.c.
1279 	 * XXX: This should move to tcp_output().
1280 	 */
1281 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1282 	    (TCP_MAXWIN << tp->request_r_scale) < sb_max)
1283 		tp->request_r_scale++;
1284 
1285 	soisconnecting(so);
1286 	TCPSTAT_INC(tcps_connattempt);
1287 	tcp_state_change(tp, TCPS_SYN_SENT);
1288 	tp->iss = tcp_new_isn(tp);
1289 	tcp_sendseqinit(tp);
1290 
1291 	return 0;
1292 
1293 out:
1294 	INP_HASH_WUNLOCK(&V_tcbinfo);
1295 	return (error);
1296 }
1297 #endif /* INET */
1298 
1299 #ifdef INET6
1300 static int
1301 tcp6_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
1302 {
1303 	struct inpcb *inp = tp->t_inpcb;
1304 	int error;
1305 
1306 	INP_WLOCK_ASSERT(inp);
1307 	INP_HASH_WLOCK(&V_tcbinfo);
1308 
1309 	if (inp->inp_lport == 0) {
1310 		error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
1311 		if (error)
1312 			goto out;
1313 	}
1314 	error = in6_pcbconnect(inp, nam, td->td_ucred);
1315 	if (error != 0)
1316 		goto out;
1317 	INP_HASH_WUNLOCK(&V_tcbinfo);
1318 
1319 	/* Compute window scaling to request.  */
1320 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1321 	    (TCP_MAXWIN << tp->request_r_scale) < sb_max)
1322 		tp->request_r_scale++;
1323 
1324 	soisconnecting(inp->inp_socket);
1325 	TCPSTAT_INC(tcps_connattempt);
1326 	tcp_state_change(tp, TCPS_SYN_SENT);
1327 	tp->iss = tcp_new_isn(tp);
1328 	tcp_sendseqinit(tp);
1329 
1330 	return 0;
1331 
1332 out:
1333 	INP_HASH_WUNLOCK(&V_tcbinfo);
1334 	return error;
1335 }
1336 #endif /* INET6 */
1337 
1338 /*
1339  * Export TCP internal state information via a struct tcp_info, based on the
1340  * Linux 2.6 API.  Not ABI compatible as our constants are mapped differently
1341  * (TCP state machine, etc).  We export all information using FreeBSD-native
1342  * constants -- for example, the numeric values for tcpi_state will differ
1343  * from Linux.
1344  */
1345 static void
1346 tcp_fill_info(struct tcpcb *tp, struct tcp_info *ti)
1347 {
1348 
1349 	INP_WLOCK_ASSERT(tp->t_inpcb);
1350 	bzero(ti, sizeof(*ti));
1351 
1352 	ti->tcpi_state = tp->t_state;
1353 	if ((tp->t_flags & TF_REQ_TSTMP) && (tp->t_flags & TF_RCVD_TSTMP))
1354 		ti->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1355 	if (tp->t_flags & TF_SACK_PERMIT)
1356 		ti->tcpi_options |= TCPI_OPT_SACK;
1357 	if ((tp->t_flags & TF_REQ_SCALE) && (tp->t_flags & TF_RCVD_SCALE)) {
1358 		ti->tcpi_options |= TCPI_OPT_WSCALE;
1359 		ti->tcpi_snd_wscale = tp->snd_scale;
1360 		ti->tcpi_rcv_wscale = tp->rcv_scale;
1361 	}
1362 	if (tp->t_flags & TF_ECN_PERMIT)
1363 		ti->tcpi_options |= TCPI_OPT_ECN;
1364 
1365 	ti->tcpi_rto = tp->t_rxtcur * tick;
1366 	ti->tcpi_last_data_recv = ((uint32_t)ticks - tp->t_rcvtime) * tick;
1367 	ti->tcpi_rtt = ((u_int64_t)tp->t_srtt * tick) >> TCP_RTT_SHIFT;
1368 	ti->tcpi_rttvar = ((u_int64_t)tp->t_rttvar * tick) >> TCP_RTTVAR_SHIFT;
1369 
1370 	ti->tcpi_snd_ssthresh = tp->snd_ssthresh;
1371 	ti->tcpi_snd_cwnd = tp->snd_cwnd;
1372 
1373 	/*
1374 	 * FreeBSD-specific extension fields for tcp_info.
1375 	 */
1376 	ti->tcpi_rcv_space = tp->rcv_wnd;
1377 	ti->tcpi_rcv_nxt = tp->rcv_nxt;
1378 	ti->tcpi_snd_wnd = tp->snd_wnd;
1379 	ti->tcpi_snd_bwnd = 0;		/* Unused, kept for compat. */
1380 	ti->tcpi_snd_nxt = tp->snd_nxt;
1381 	ti->tcpi_snd_mss = tp->t_maxseg;
1382 	ti->tcpi_rcv_mss = tp->t_maxseg;
1383 	if (tp->t_flags & TF_TOE)
1384 		ti->tcpi_options |= TCPI_OPT_TOE;
1385 	ti->tcpi_snd_rexmitpack = tp->t_sndrexmitpack;
1386 	ti->tcpi_rcv_ooopack = tp->t_rcvoopack;
1387 	ti->tcpi_snd_zerowin = tp->t_sndzerowin;
1388 }
1389 
1390 /*
1391  * tcp_ctloutput() must drop the inpcb lock before performing copyin on
1392  * socket option arguments.  When it re-acquires the lock after the copy, it
1393  * has to revalidate that the connection is still valid for the socket
1394  * option.
1395  */
1396 #define INP_WLOCK_RECHECK_CLEANUP(inp, cleanup) do {			\
1397 	INP_WLOCK(inp);							\
1398 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {		\
1399 		INP_WUNLOCK(inp);					\
1400 		cleanup;						\
1401 		return (ECONNRESET);					\
1402 	}								\
1403 	tp = intotcpcb(inp);						\
1404 } while(0)
1405 #define INP_WLOCK_RECHECK(inp) INP_WLOCK_RECHECK_CLEANUP((inp), /* noop */)
1406 
1407 int
1408 tcp_ctloutput(struct socket *so, struct sockopt *sopt)
1409 {
1410 	int	error;
1411 	struct	inpcb *inp;
1412 	struct	tcpcb *tp;
1413 	struct tcp_function_block *blk;
1414 	struct tcp_function_set fsn;
1415 
1416 	error = 0;
1417 	inp = sotoinpcb(so);
1418 	KASSERT(inp != NULL, ("tcp_ctloutput: inp == NULL"));
1419 	INP_WLOCK(inp);
1420 	if (sopt->sopt_level != IPPROTO_TCP) {
1421 #ifdef INET6
1422 		if (inp->inp_vflag & INP_IPV6PROTO) {
1423 			INP_WUNLOCK(inp);
1424 			error = ip6_ctloutput(so, sopt);
1425 		}
1426 #endif /* INET6 */
1427 #if defined(INET6) && defined(INET)
1428 		else
1429 #endif
1430 #ifdef INET
1431 		{
1432 			INP_WUNLOCK(inp);
1433 			error = ip_ctloutput(so, sopt);
1434 		}
1435 #endif
1436 		return (error);
1437 	}
1438 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1439 		INP_WUNLOCK(inp);
1440 		return (ECONNRESET);
1441 	}
1442 	tp = intotcpcb(inp);
1443 	/*
1444 	 * Protect the TCP option TCP_FUNCTION_BLK so
1445 	 * that a sub-function can *never* overwrite this.
1446 	 */
1447 	if ((sopt->sopt_dir == SOPT_SET) &&
1448 	    (sopt->sopt_name == TCP_FUNCTION_BLK)) {
1449 		INP_WUNLOCK(inp);
1450 		error = sooptcopyin(sopt, &fsn, sizeof fsn,
1451 		    sizeof fsn);
1452 		if (error)
1453 			return (error);
1454 		INP_WLOCK_RECHECK(inp);
1455 		blk = find_and_ref_tcp_functions(&fsn);
1456 		if (blk == NULL) {
1457 			INP_WUNLOCK(inp);
1458 			return (ENOENT);
1459 		}
1460 		if (tp->t_fb == blk) {
1461 			/* You already have this */
1462 			refcount_release(&blk->tfb_refcnt);
1463 			INP_WUNLOCK(inp);
1464 			return (0);
1465 		}
1466 		if (tp->t_state != TCPS_CLOSED) {
1467 			int error=EINVAL;
1468 			/*
1469 			 * The user has advanced the state
1470 			 * past the initial point, we may not
1471 			 * be able to switch.
1472 			 */
1473 			if (blk->tfb_tcp_handoff_ok != NULL) {
1474 				/*
1475 				 * Does the stack provide a
1476 				 * query mechanism, if so it may
1477 				 * still be possible?
1478 				 */
1479 				error = (*blk->tfb_tcp_handoff_ok)(tp);
1480 			}
1481 			if (error) {
1482 				refcount_release(&blk->tfb_refcnt);
1483 				INP_WUNLOCK(inp);
1484 				return(error);
1485 			}
1486 		}
1487 		if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
1488 			refcount_release(&blk->tfb_refcnt);
1489 			INP_WUNLOCK(inp);
1490 			return (ENOENT);
1491 		}
1492 		/*
1493 		 * Release the old refcnt, the
1494 		 * lookup acquired a ref on the
1495 		 * new one already.
1496 		 */
1497 		if (tp->t_fb->tfb_tcp_fb_fini) {
1498 			/*
1499 			 * Tell the stack to cleanup with 0 i.e.
1500 			 * the tcb is not going away.
1501 			 */
1502 			(*tp->t_fb->tfb_tcp_fb_fini)(tp, 0);
1503 		}
1504 		refcount_release(&tp->t_fb->tfb_refcnt);
1505 		tp->t_fb = blk;
1506 		if (tp->t_fb->tfb_tcp_fb_init) {
1507 			(*tp->t_fb->tfb_tcp_fb_init)(tp);
1508 		}
1509 #ifdef TCP_OFFLOAD
1510 		if (tp->t_flags & TF_TOE) {
1511 			tcp_offload_ctloutput(tp, sopt->sopt_dir,
1512 			     sopt->sopt_name);
1513 		}
1514 #endif
1515 		INP_WUNLOCK(inp);
1516 		return (error);
1517 	} else if ((sopt->sopt_dir == SOPT_GET) &&
1518 	    (sopt->sopt_name == TCP_FUNCTION_BLK)) {
1519 		strcpy(fsn.function_set_name, tp->t_fb->tfb_tcp_block_name);
1520 		fsn.pcbcnt = tp->t_fb->tfb_refcnt;
1521 		INP_WUNLOCK(inp);
1522 		error = sooptcopyout(sopt, &fsn, sizeof fsn);
1523 		return (error);
1524 	}
1525 	/* Pass in the INP locked, called must unlock it */
1526 	return (tp->t_fb->tfb_tcp_ctloutput(so, sopt, inp, tp));
1527 }
1528 
1529 int
1530 tcp_default_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp)
1531 {
1532 	int	error, opt, optval;
1533 	u_int	ui;
1534 	struct	tcp_info ti;
1535 	struct cc_algo *algo;
1536 	char	*pbuf, buf[TCP_CA_NAME_MAX];
1537 	size_t	len;
1538 
1539 	/*
1540 	 * For TCP_CCALGOOPT forward the control to CC module, for both
1541 	 * SOPT_SET and SOPT_GET.
1542 	 */
1543 	switch (sopt->sopt_name) {
1544 	case TCP_CCALGOOPT:
1545 		INP_WUNLOCK(inp);
1546 		pbuf = malloc(sopt->sopt_valsize, M_TEMP, M_WAITOK | M_ZERO);
1547 		error = sooptcopyin(sopt, pbuf, sopt->sopt_valsize,
1548 		    sopt->sopt_valsize);
1549 		if (error) {
1550 			free(pbuf, M_TEMP);
1551 			return (error);
1552 		}
1553 		INP_WLOCK_RECHECK_CLEANUP(inp, free(pbuf, M_TEMP));
1554 		if (CC_ALGO(tp)->ctl_output != NULL)
1555 			error = CC_ALGO(tp)->ctl_output(tp->ccv, sopt, pbuf);
1556 		else
1557 			error = ENOENT;
1558 		INP_WUNLOCK(inp);
1559 		if (error == 0 && sopt->sopt_dir == SOPT_GET)
1560 			error = sooptcopyout(sopt, pbuf, sopt->sopt_valsize);
1561 		free(pbuf, M_TEMP);
1562 		return (error);
1563 	}
1564 
1565 	switch (sopt->sopt_dir) {
1566 	case SOPT_SET:
1567 		switch (sopt->sopt_name) {
1568 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
1569 		case TCP_MD5SIG:
1570 			if (!TCPMD5_ENABLED()) {
1571 				INP_WUNLOCK(inp);
1572 				return (ENOPROTOOPT);
1573 			}
1574 			error = TCPMD5_PCBCTL(inp, sopt);
1575 			if (error)
1576 				return (error);
1577 			goto unlock_and_done;
1578 #endif /* IPSEC */
1579 
1580 		case TCP_NODELAY:
1581 		case TCP_NOOPT:
1582 			INP_WUNLOCK(inp);
1583 			error = sooptcopyin(sopt, &optval, sizeof optval,
1584 			    sizeof optval);
1585 			if (error)
1586 				return (error);
1587 
1588 			INP_WLOCK_RECHECK(inp);
1589 			switch (sopt->sopt_name) {
1590 			case TCP_NODELAY:
1591 				opt = TF_NODELAY;
1592 				break;
1593 			case TCP_NOOPT:
1594 				opt = TF_NOOPT;
1595 				break;
1596 			default:
1597 				opt = 0; /* dead code to fool gcc */
1598 				break;
1599 			}
1600 
1601 			if (optval)
1602 				tp->t_flags |= opt;
1603 			else
1604 				tp->t_flags &= ~opt;
1605 unlock_and_done:
1606 #ifdef TCP_OFFLOAD
1607 			if (tp->t_flags & TF_TOE) {
1608 				tcp_offload_ctloutput(tp, sopt->sopt_dir,
1609 				    sopt->sopt_name);
1610 			}
1611 #endif
1612 			INP_WUNLOCK(inp);
1613 			break;
1614 
1615 		case TCP_NOPUSH:
1616 			INP_WUNLOCK(inp);
1617 			error = sooptcopyin(sopt, &optval, sizeof optval,
1618 			    sizeof optval);
1619 			if (error)
1620 				return (error);
1621 
1622 			INP_WLOCK_RECHECK(inp);
1623 			if (optval)
1624 				tp->t_flags |= TF_NOPUSH;
1625 			else if (tp->t_flags & TF_NOPUSH) {
1626 				tp->t_flags &= ~TF_NOPUSH;
1627 				if (TCPS_HAVEESTABLISHED(tp->t_state))
1628 					error = tp->t_fb->tfb_tcp_output(tp);
1629 			}
1630 			goto unlock_and_done;
1631 
1632 		case TCP_MAXSEG:
1633 			INP_WUNLOCK(inp);
1634 			error = sooptcopyin(sopt, &optval, sizeof optval,
1635 			    sizeof optval);
1636 			if (error)
1637 				return (error);
1638 
1639 			INP_WLOCK_RECHECK(inp);
1640 			if (optval > 0 && optval <= tp->t_maxseg &&
1641 			    optval + 40 >= V_tcp_minmss)
1642 				tp->t_maxseg = optval;
1643 			else
1644 				error = EINVAL;
1645 			goto unlock_and_done;
1646 
1647 		case TCP_INFO:
1648 			INP_WUNLOCK(inp);
1649 			error = EINVAL;
1650 			break;
1651 
1652 		case TCP_CONGESTION:
1653 			INP_WUNLOCK(inp);
1654 			error = sooptcopyin(sopt, buf, TCP_CA_NAME_MAX - 1, 1);
1655 			if (error)
1656 				break;
1657 			buf[sopt->sopt_valsize] = '\0';
1658 			INP_WLOCK_RECHECK(inp);
1659 			CC_LIST_RLOCK();
1660 			STAILQ_FOREACH(algo, &cc_list, entries)
1661 				if (strncmp(buf, algo->name,
1662 				    TCP_CA_NAME_MAX) == 0)
1663 					break;
1664 			CC_LIST_RUNLOCK();
1665 			if (algo == NULL) {
1666 				INP_WUNLOCK(inp);
1667 				error = EINVAL;
1668 				break;
1669 			}
1670 			/*
1671 			 * We hold a write lock over the tcb so it's safe to
1672 			 * do these things without ordering concerns.
1673 			 */
1674 			if (CC_ALGO(tp)->cb_destroy != NULL)
1675 				CC_ALGO(tp)->cb_destroy(tp->ccv);
1676 			CC_ALGO(tp) = algo;
1677 			/*
1678 			 * If something goes pear shaped initialising the new
1679 			 * algo, fall back to newreno (which does not
1680 			 * require initialisation).
1681 			 */
1682 			if (algo->cb_init != NULL &&
1683 			    algo->cb_init(tp->ccv) != 0) {
1684 				CC_ALGO(tp) = &newreno_cc_algo;
1685 				/*
1686 				 * The only reason init should fail is
1687 				 * because of malloc.
1688 				 */
1689 				error = ENOMEM;
1690 			}
1691 			INP_WUNLOCK(inp);
1692 			break;
1693 
1694 		case TCP_KEEPIDLE:
1695 		case TCP_KEEPINTVL:
1696 		case TCP_KEEPINIT:
1697 			INP_WUNLOCK(inp);
1698 			error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
1699 			if (error)
1700 				return (error);
1701 
1702 			if (ui > (UINT_MAX / hz)) {
1703 				error = EINVAL;
1704 				break;
1705 			}
1706 			ui *= hz;
1707 
1708 			INP_WLOCK_RECHECK(inp);
1709 			switch (sopt->sopt_name) {
1710 			case TCP_KEEPIDLE:
1711 				tp->t_keepidle = ui;
1712 				/*
1713 				 * XXX: better check current remaining
1714 				 * timeout and "merge" it with new value.
1715 				 */
1716 				if ((tp->t_state > TCPS_LISTEN) &&
1717 				    (tp->t_state <= TCPS_CLOSING))
1718 					tcp_timer_activate(tp, TT_KEEP,
1719 					    TP_KEEPIDLE(tp));
1720 				break;
1721 			case TCP_KEEPINTVL:
1722 				tp->t_keepintvl = ui;
1723 				if ((tp->t_state == TCPS_FIN_WAIT_2) &&
1724 				    (TP_MAXIDLE(tp) > 0))
1725 					tcp_timer_activate(tp, TT_2MSL,
1726 					    TP_MAXIDLE(tp));
1727 				break;
1728 			case TCP_KEEPINIT:
1729 				tp->t_keepinit = ui;
1730 				if (tp->t_state == TCPS_SYN_RECEIVED ||
1731 				    tp->t_state == TCPS_SYN_SENT)
1732 					tcp_timer_activate(tp, TT_KEEP,
1733 					    TP_KEEPINIT(tp));
1734 				break;
1735 			}
1736 			goto unlock_and_done;
1737 
1738 		case TCP_KEEPCNT:
1739 			INP_WUNLOCK(inp);
1740 			error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
1741 			if (error)
1742 				return (error);
1743 
1744 			INP_WLOCK_RECHECK(inp);
1745 			tp->t_keepcnt = ui;
1746 			if ((tp->t_state == TCPS_FIN_WAIT_2) &&
1747 			    (TP_MAXIDLE(tp) > 0))
1748 				tcp_timer_activate(tp, TT_2MSL,
1749 				    TP_MAXIDLE(tp));
1750 			goto unlock_and_done;
1751 
1752 #ifdef TCPPCAP
1753 		case TCP_PCAP_OUT:
1754 		case TCP_PCAP_IN:
1755 			INP_WUNLOCK(inp);
1756 			error = sooptcopyin(sopt, &optval, sizeof optval,
1757 			    sizeof optval);
1758 			if (error)
1759 				return (error);
1760 
1761 			INP_WLOCK_RECHECK(inp);
1762 			if (optval >= 0)
1763 				tcp_pcap_set_sock_max(TCP_PCAP_OUT ?
1764 					&(tp->t_outpkts) : &(tp->t_inpkts),
1765 					optval);
1766 			else
1767 				error = EINVAL;
1768 			goto unlock_and_done;
1769 #endif
1770 
1771 #ifdef TCP_RFC7413
1772 		case TCP_FASTOPEN:
1773 			INP_WUNLOCK(inp);
1774 			if (!V_tcp_fastopen_enabled)
1775 				return (EPERM);
1776 
1777 			error = sooptcopyin(sopt, &optval, sizeof optval,
1778 			    sizeof optval);
1779 			if (error)
1780 				return (error);
1781 
1782 			INP_WLOCK_RECHECK(inp);
1783 			if (optval) {
1784 				tp->t_flags |= TF_FASTOPEN;
1785 				if ((tp->t_state == TCPS_LISTEN) &&
1786 				    (tp->t_tfo_pending == NULL))
1787 					tp->t_tfo_pending =
1788 					    tcp_fastopen_alloc_counter();
1789 			} else
1790 				tp->t_flags &= ~TF_FASTOPEN;
1791 			goto unlock_and_done;
1792 #endif
1793 
1794 		default:
1795 			INP_WUNLOCK(inp);
1796 			error = ENOPROTOOPT;
1797 			break;
1798 		}
1799 		break;
1800 
1801 	case SOPT_GET:
1802 		tp = intotcpcb(inp);
1803 		switch (sopt->sopt_name) {
1804 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
1805 		case TCP_MD5SIG:
1806 			if (!TCPMD5_ENABLED()) {
1807 				INP_WUNLOCK(inp);
1808 				return (ENOPROTOOPT);
1809 			}
1810 			error = TCPMD5_PCBCTL(inp, sopt);
1811 			break;
1812 #endif
1813 
1814 		case TCP_NODELAY:
1815 			optval = tp->t_flags & TF_NODELAY;
1816 			INP_WUNLOCK(inp);
1817 			error = sooptcopyout(sopt, &optval, sizeof optval);
1818 			break;
1819 		case TCP_MAXSEG:
1820 			optval = tp->t_maxseg;
1821 			INP_WUNLOCK(inp);
1822 			error = sooptcopyout(sopt, &optval, sizeof optval);
1823 			break;
1824 		case TCP_NOOPT:
1825 			optval = tp->t_flags & TF_NOOPT;
1826 			INP_WUNLOCK(inp);
1827 			error = sooptcopyout(sopt, &optval, sizeof optval);
1828 			break;
1829 		case TCP_NOPUSH:
1830 			optval = tp->t_flags & TF_NOPUSH;
1831 			INP_WUNLOCK(inp);
1832 			error = sooptcopyout(sopt, &optval, sizeof optval);
1833 			break;
1834 		case TCP_INFO:
1835 			tcp_fill_info(tp, &ti);
1836 			INP_WUNLOCK(inp);
1837 			error = sooptcopyout(sopt, &ti, sizeof ti);
1838 			break;
1839 		case TCP_CONGESTION:
1840 			len = strlcpy(buf, CC_ALGO(tp)->name, TCP_CA_NAME_MAX);
1841 			INP_WUNLOCK(inp);
1842 			error = sooptcopyout(sopt, buf, len + 1);
1843 			break;
1844 		case TCP_KEEPIDLE:
1845 		case TCP_KEEPINTVL:
1846 		case TCP_KEEPINIT:
1847 		case TCP_KEEPCNT:
1848 			switch (sopt->sopt_name) {
1849 			case TCP_KEEPIDLE:
1850 				ui = TP_KEEPIDLE(tp) / hz;
1851 				break;
1852 			case TCP_KEEPINTVL:
1853 				ui = TP_KEEPINTVL(tp) / hz;
1854 				break;
1855 			case TCP_KEEPINIT:
1856 				ui = TP_KEEPINIT(tp) / hz;
1857 				break;
1858 			case TCP_KEEPCNT:
1859 				ui = TP_KEEPCNT(tp);
1860 				break;
1861 			}
1862 			INP_WUNLOCK(inp);
1863 			error = sooptcopyout(sopt, &ui, sizeof(ui));
1864 			break;
1865 #ifdef TCPPCAP
1866 		case TCP_PCAP_OUT:
1867 		case TCP_PCAP_IN:
1868 			optval = tcp_pcap_get_sock_max(TCP_PCAP_OUT ?
1869 					&(tp->t_outpkts) : &(tp->t_inpkts));
1870 			INP_WUNLOCK(inp);
1871 			error = sooptcopyout(sopt, &optval, sizeof optval);
1872 			break;
1873 #endif
1874 
1875 #ifdef TCP_RFC7413
1876 		case TCP_FASTOPEN:
1877 			optval = tp->t_flags & TF_FASTOPEN;
1878 			INP_WUNLOCK(inp);
1879 			error = sooptcopyout(sopt, &optval, sizeof optval);
1880 			break;
1881 #endif
1882 		default:
1883 			INP_WUNLOCK(inp);
1884 			error = ENOPROTOOPT;
1885 			break;
1886 		}
1887 		break;
1888 	}
1889 	return (error);
1890 }
1891 #undef INP_WLOCK_RECHECK
1892 #undef INP_WLOCK_RECHECK_CLEANUP
1893 
1894 /*
1895  * Attach TCP protocol to socket, allocating
1896  * internet protocol control block, tcp control block,
1897  * bufer space, and entering LISTEN state if to accept connections.
1898  */
1899 static int
1900 tcp_attach(struct socket *so)
1901 {
1902 	struct tcpcb *tp;
1903 	struct inpcb *inp;
1904 	int error;
1905 
1906 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
1907 		error = soreserve(so, V_tcp_sendspace, V_tcp_recvspace);
1908 		if (error)
1909 			return (error);
1910 	}
1911 	so->so_rcv.sb_flags |= SB_AUTOSIZE;
1912 	so->so_snd.sb_flags |= SB_AUTOSIZE;
1913 	INP_INFO_RLOCK(&V_tcbinfo);
1914 	error = in_pcballoc(so, &V_tcbinfo);
1915 	if (error) {
1916 		INP_INFO_RUNLOCK(&V_tcbinfo);
1917 		return (error);
1918 	}
1919 	inp = sotoinpcb(so);
1920 #ifdef INET6
1921 	if (inp->inp_vflag & INP_IPV6PROTO) {
1922 		inp->inp_vflag |= INP_IPV6;
1923 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
1924 			inp->inp_vflag |= INP_IPV4;
1925 		inp->in6p_hops = -1;	/* use kernel default */
1926 	}
1927 	else
1928 #endif
1929 	inp->inp_vflag |= INP_IPV4;
1930 	tp = tcp_newtcpcb(inp);
1931 	if (tp == NULL) {
1932 		in_pcbdetach(inp);
1933 		in_pcbfree(inp);
1934 		INP_INFO_RUNLOCK(&V_tcbinfo);
1935 		return (ENOBUFS);
1936 	}
1937 	tp->t_state = TCPS_CLOSED;
1938 	INP_WUNLOCK(inp);
1939 	INP_INFO_RUNLOCK(&V_tcbinfo);
1940 	TCPSTATES_INC(TCPS_CLOSED);
1941 	return (0);
1942 }
1943 
1944 /*
1945  * Initiate (or continue) disconnect.
1946  * If embryonic state, just send reset (once).
1947  * If in ``let data drain'' option and linger null, just drop.
1948  * Otherwise (hard), mark socket disconnecting and drop
1949  * current input data; switch states based on user close, and
1950  * send segment to peer (with FIN).
1951  */
1952 static void
1953 tcp_disconnect(struct tcpcb *tp)
1954 {
1955 	struct inpcb *inp = tp->t_inpcb;
1956 	struct socket *so = inp->inp_socket;
1957 
1958 	INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
1959 	INP_WLOCK_ASSERT(inp);
1960 
1961 	/*
1962 	 * Neither tcp_close() nor tcp_drop() should return NULL, as the
1963 	 * socket is still open.
1964 	 */
1965 	if (tp->t_state < TCPS_ESTABLISHED) {
1966 		tp = tcp_close(tp);
1967 		KASSERT(tp != NULL,
1968 		    ("tcp_disconnect: tcp_close() returned NULL"));
1969 	} else if ((so->so_options & SO_LINGER) && so->so_linger == 0) {
1970 		tp = tcp_drop(tp, 0);
1971 		KASSERT(tp != NULL,
1972 		    ("tcp_disconnect: tcp_drop() returned NULL"));
1973 	} else {
1974 		soisdisconnecting(so);
1975 		sbflush(&so->so_rcv);
1976 		tcp_usrclosed(tp);
1977 		if (!(inp->inp_flags & INP_DROPPED))
1978 			tp->t_fb->tfb_tcp_output(tp);
1979 	}
1980 }
1981 
1982 /*
1983  * User issued close, and wish to trail through shutdown states:
1984  * if never received SYN, just forget it.  If got a SYN from peer,
1985  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
1986  * If already got a FIN from peer, then almost done; go to LAST_ACK
1987  * state.  In all other cases, have already sent FIN to peer (e.g.
1988  * after PRU_SHUTDOWN), and just have to play tedious game waiting
1989  * for peer to send FIN or not respond to keep-alives, etc.
1990  * We can let the user exit from the close as soon as the FIN is acked.
1991  */
1992 static void
1993 tcp_usrclosed(struct tcpcb *tp)
1994 {
1995 
1996 	INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
1997 	INP_WLOCK_ASSERT(tp->t_inpcb);
1998 
1999 	switch (tp->t_state) {
2000 	case TCPS_LISTEN:
2001 #ifdef TCP_OFFLOAD
2002 		tcp_offload_listen_stop(tp);
2003 #endif
2004 		tcp_state_change(tp, TCPS_CLOSED);
2005 		/* FALLTHROUGH */
2006 	case TCPS_CLOSED:
2007 		tp = tcp_close(tp);
2008 		/*
2009 		 * tcp_close() should never return NULL here as the socket is
2010 		 * still open.
2011 		 */
2012 		KASSERT(tp != NULL,
2013 		    ("tcp_usrclosed: tcp_close() returned NULL"));
2014 		break;
2015 
2016 	case TCPS_SYN_SENT:
2017 	case TCPS_SYN_RECEIVED:
2018 		tp->t_flags |= TF_NEEDFIN;
2019 		break;
2020 
2021 	case TCPS_ESTABLISHED:
2022 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
2023 		break;
2024 
2025 	case TCPS_CLOSE_WAIT:
2026 		tcp_state_change(tp, TCPS_LAST_ACK);
2027 		break;
2028 	}
2029 	if (tp->t_state >= TCPS_FIN_WAIT_2) {
2030 		soisdisconnected(tp->t_inpcb->inp_socket);
2031 		/* Prevent the connection hanging in FIN_WAIT_2 forever. */
2032 		if (tp->t_state == TCPS_FIN_WAIT_2) {
2033 			int timeout;
2034 
2035 			timeout = (tcp_fast_finwait2_recycle) ?
2036 			    tcp_finwait2_timeout : TP_MAXIDLE(tp);
2037 			tcp_timer_activate(tp, TT_2MSL, timeout);
2038 		}
2039 	}
2040 }
2041 
2042 #ifdef DDB
2043 static void
2044 db_print_indent(int indent)
2045 {
2046 	int i;
2047 
2048 	for (i = 0; i < indent; i++)
2049 		db_printf(" ");
2050 }
2051 
2052 static void
2053 db_print_tstate(int t_state)
2054 {
2055 
2056 	switch (t_state) {
2057 	case TCPS_CLOSED:
2058 		db_printf("TCPS_CLOSED");
2059 		return;
2060 
2061 	case TCPS_LISTEN:
2062 		db_printf("TCPS_LISTEN");
2063 		return;
2064 
2065 	case TCPS_SYN_SENT:
2066 		db_printf("TCPS_SYN_SENT");
2067 		return;
2068 
2069 	case TCPS_SYN_RECEIVED:
2070 		db_printf("TCPS_SYN_RECEIVED");
2071 		return;
2072 
2073 	case TCPS_ESTABLISHED:
2074 		db_printf("TCPS_ESTABLISHED");
2075 		return;
2076 
2077 	case TCPS_CLOSE_WAIT:
2078 		db_printf("TCPS_CLOSE_WAIT");
2079 		return;
2080 
2081 	case TCPS_FIN_WAIT_1:
2082 		db_printf("TCPS_FIN_WAIT_1");
2083 		return;
2084 
2085 	case TCPS_CLOSING:
2086 		db_printf("TCPS_CLOSING");
2087 		return;
2088 
2089 	case TCPS_LAST_ACK:
2090 		db_printf("TCPS_LAST_ACK");
2091 		return;
2092 
2093 	case TCPS_FIN_WAIT_2:
2094 		db_printf("TCPS_FIN_WAIT_2");
2095 		return;
2096 
2097 	case TCPS_TIME_WAIT:
2098 		db_printf("TCPS_TIME_WAIT");
2099 		return;
2100 
2101 	default:
2102 		db_printf("unknown");
2103 		return;
2104 	}
2105 }
2106 
2107 static void
2108 db_print_tflags(u_int t_flags)
2109 {
2110 	int comma;
2111 
2112 	comma = 0;
2113 	if (t_flags & TF_ACKNOW) {
2114 		db_printf("%sTF_ACKNOW", comma ? ", " : "");
2115 		comma = 1;
2116 	}
2117 	if (t_flags & TF_DELACK) {
2118 		db_printf("%sTF_DELACK", comma ? ", " : "");
2119 		comma = 1;
2120 	}
2121 	if (t_flags & TF_NODELAY) {
2122 		db_printf("%sTF_NODELAY", comma ? ", " : "");
2123 		comma = 1;
2124 	}
2125 	if (t_flags & TF_NOOPT) {
2126 		db_printf("%sTF_NOOPT", comma ? ", " : "");
2127 		comma = 1;
2128 	}
2129 	if (t_flags & TF_SENTFIN) {
2130 		db_printf("%sTF_SENTFIN", comma ? ", " : "");
2131 		comma = 1;
2132 	}
2133 	if (t_flags & TF_REQ_SCALE) {
2134 		db_printf("%sTF_REQ_SCALE", comma ? ", " : "");
2135 		comma = 1;
2136 	}
2137 	if (t_flags & TF_RCVD_SCALE) {
2138 		db_printf("%sTF_RECVD_SCALE", comma ? ", " : "");
2139 		comma = 1;
2140 	}
2141 	if (t_flags & TF_REQ_TSTMP) {
2142 		db_printf("%sTF_REQ_TSTMP", comma ? ", " : "");
2143 		comma = 1;
2144 	}
2145 	if (t_flags & TF_RCVD_TSTMP) {
2146 		db_printf("%sTF_RCVD_TSTMP", comma ? ", " : "");
2147 		comma = 1;
2148 	}
2149 	if (t_flags & TF_SACK_PERMIT) {
2150 		db_printf("%sTF_SACK_PERMIT", comma ? ", " : "");
2151 		comma = 1;
2152 	}
2153 	if (t_flags & TF_NEEDSYN) {
2154 		db_printf("%sTF_NEEDSYN", comma ? ", " : "");
2155 		comma = 1;
2156 	}
2157 	if (t_flags & TF_NEEDFIN) {
2158 		db_printf("%sTF_NEEDFIN", comma ? ", " : "");
2159 		comma = 1;
2160 	}
2161 	if (t_flags & TF_NOPUSH) {
2162 		db_printf("%sTF_NOPUSH", comma ? ", " : "");
2163 		comma = 1;
2164 	}
2165 	if (t_flags & TF_MORETOCOME) {
2166 		db_printf("%sTF_MORETOCOME", comma ? ", " : "");
2167 		comma = 1;
2168 	}
2169 	if (t_flags & TF_LQ_OVERFLOW) {
2170 		db_printf("%sTF_LQ_OVERFLOW", comma ? ", " : "");
2171 		comma = 1;
2172 	}
2173 	if (t_flags & TF_LASTIDLE) {
2174 		db_printf("%sTF_LASTIDLE", comma ? ", " : "");
2175 		comma = 1;
2176 	}
2177 	if (t_flags & TF_RXWIN0SENT) {
2178 		db_printf("%sTF_RXWIN0SENT", comma ? ", " : "");
2179 		comma = 1;
2180 	}
2181 	if (t_flags & TF_FASTRECOVERY) {
2182 		db_printf("%sTF_FASTRECOVERY", comma ? ", " : "");
2183 		comma = 1;
2184 	}
2185 	if (t_flags & TF_CONGRECOVERY) {
2186 		db_printf("%sTF_CONGRECOVERY", comma ? ", " : "");
2187 		comma = 1;
2188 	}
2189 	if (t_flags & TF_WASFRECOVERY) {
2190 		db_printf("%sTF_WASFRECOVERY", comma ? ", " : "");
2191 		comma = 1;
2192 	}
2193 	if (t_flags & TF_SIGNATURE) {
2194 		db_printf("%sTF_SIGNATURE", comma ? ", " : "");
2195 		comma = 1;
2196 	}
2197 	if (t_flags & TF_FORCEDATA) {
2198 		db_printf("%sTF_FORCEDATA", comma ? ", " : "");
2199 		comma = 1;
2200 	}
2201 	if (t_flags & TF_TSO) {
2202 		db_printf("%sTF_TSO", comma ? ", " : "");
2203 		comma = 1;
2204 	}
2205 	if (t_flags & TF_ECN_PERMIT) {
2206 		db_printf("%sTF_ECN_PERMIT", comma ? ", " : "");
2207 		comma = 1;
2208 	}
2209 	if (t_flags & TF_FASTOPEN) {
2210 		db_printf("%sTF_FASTOPEN", comma ? ", " : "");
2211 		comma = 1;
2212 	}
2213 }
2214 
2215 static void
2216 db_print_toobflags(char t_oobflags)
2217 {
2218 	int comma;
2219 
2220 	comma = 0;
2221 	if (t_oobflags & TCPOOB_HAVEDATA) {
2222 		db_printf("%sTCPOOB_HAVEDATA", comma ? ", " : "");
2223 		comma = 1;
2224 	}
2225 	if (t_oobflags & TCPOOB_HADDATA) {
2226 		db_printf("%sTCPOOB_HADDATA", comma ? ", " : "");
2227 		comma = 1;
2228 	}
2229 }
2230 
2231 static void
2232 db_print_tcpcb(struct tcpcb *tp, const char *name, int indent)
2233 {
2234 
2235 	db_print_indent(indent);
2236 	db_printf("%s at %p\n", name, tp);
2237 
2238 	indent += 2;
2239 
2240 	db_print_indent(indent);
2241 	db_printf("t_segq first: %p   t_segqlen: %d   t_dupacks: %d\n",
2242 	   LIST_FIRST(&tp->t_segq), tp->t_segqlen, tp->t_dupacks);
2243 
2244 	db_print_indent(indent);
2245 	db_printf("tt_rexmt: %p   tt_persist: %p   tt_keep: %p\n",
2246 	    &tp->t_timers->tt_rexmt, &tp->t_timers->tt_persist, &tp->t_timers->tt_keep);
2247 
2248 	db_print_indent(indent);
2249 	db_printf("tt_2msl: %p   tt_delack: %p   t_inpcb: %p\n", &tp->t_timers->tt_2msl,
2250 	    &tp->t_timers->tt_delack, tp->t_inpcb);
2251 
2252 	db_print_indent(indent);
2253 	db_printf("t_state: %d (", tp->t_state);
2254 	db_print_tstate(tp->t_state);
2255 	db_printf(")\n");
2256 
2257 	db_print_indent(indent);
2258 	db_printf("t_flags: 0x%x (", tp->t_flags);
2259 	db_print_tflags(tp->t_flags);
2260 	db_printf(")\n");
2261 
2262 	db_print_indent(indent);
2263 	db_printf("snd_una: 0x%08x   snd_max: 0x%08x   snd_nxt: x0%08x\n",
2264 	    tp->snd_una, tp->snd_max, tp->snd_nxt);
2265 
2266 	db_print_indent(indent);
2267 	db_printf("snd_up: 0x%08x   snd_wl1: 0x%08x   snd_wl2: 0x%08x\n",
2268 	   tp->snd_up, tp->snd_wl1, tp->snd_wl2);
2269 
2270 	db_print_indent(indent);
2271 	db_printf("iss: 0x%08x   irs: 0x%08x   rcv_nxt: 0x%08x\n",
2272 	    tp->iss, tp->irs, tp->rcv_nxt);
2273 
2274 	db_print_indent(indent);
2275 	db_printf("rcv_adv: 0x%08x   rcv_wnd: %u   rcv_up: 0x%08x\n",
2276 	    tp->rcv_adv, tp->rcv_wnd, tp->rcv_up);
2277 
2278 	db_print_indent(indent);
2279 	db_printf("snd_wnd: %u   snd_cwnd: %u\n",
2280 	   tp->snd_wnd, tp->snd_cwnd);
2281 
2282 	db_print_indent(indent);
2283 	db_printf("snd_ssthresh: %u   snd_recover: "
2284 	    "0x%08x\n", tp->snd_ssthresh, tp->snd_recover);
2285 
2286 	db_print_indent(indent);
2287 	db_printf("t_rcvtime: %u   t_startime: %u\n",
2288 	    tp->t_rcvtime, tp->t_starttime);
2289 
2290 	db_print_indent(indent);
2291 	db_printf("t_rttime: %u   t_rtsq: 0x%08x\n",
2292 	    tp->t_rtttime, tp->t_rtseq);
2293 
2294 	db_print_indent(indent);
2295 	db_printf("t_rxtcur: %d   t_maxseg: %u   t_srtt: %d\n",
2296 	    tp->t_rxtcur, tp->t_maxseg, tp->t_srtt);
2297 
2298 	db_print_indent(indent);
2299 	db_printf("t_rttvar: %d   t_rxtshift: %d   t_rttmin: %u   "
2300 	    "t_rttbest: %u\n", tp->t_rttvar, tp->t_rxtshift, tp->t_rttmin,
2301 	    tp->t_rttbest);
2302 
2303 	db_print_indent(indent);
2304 	db_printf("t_rttupdated: %lu   max_sndwnd: %u   t_softerror: %d\n",
2305 	    tp->t_rttupdated, tp->max_sndwnd, tp->t_softerror);
2306 
2307 	db_print_indent(indent);
2308 	db_printf("t_oobflags: 0x%x (", tp->t_oobflags);
2309 	db_print_toobflags(tp->t_oobflags);
2310 	db_printf(")   t_iobc: 0x%02x\n", tp->t_iobc);
2311 
2312 	db_print_indent(indent);
2313 	db_printf("snd_scale: %u   rcv_scale: %u   request_r_scale: %u\n",
2314 	    tp->snd_scale, tp->rcv_scale, tp->request_r_scale);
2315 
2316 	db_print_indent(indent);
2317 	db_printf("ts_recent: %u   ts_recent_age: %u\n",
2318 	    tp->ts_recent, tp->ts_recent_age);
2319 
2320 	db_print_indent(indent);
2321 	db_printf("ts_offset: %u   last_ack_sent: 0x%08x   snd_cwnd_prev: "
2322 	    "%u\n", tp->ts_offset, tp->last_ack_sent, tp->snd_cwnd_prev);
2323 
2324 	db_print_indent(indent);
2325 	db_printf("snd_ssthresh_prev: %u   snd_recover_prev: 0x%08x   "
2326 	    "t_badrxtwin: %u\n", tp->snd_ssthresh_prev,
2327 	    tp->snd_recover_prev, tp->t_badrxtwin);
2328 
2329 	db_print_indent(indent);
2330 	db_printf("snd_numholes: %d  snd_holes first: %p\n",
2331 	    tp->snd_numholes, TAILQ_FIRST(&tp->snd_holes));
2332 
2333 	db_print_indent(indent);
2334 	db_printf("snd_fack: 0x%08x   rcv_numsacks: %d   sack_newdata: "
2335 	    "0x%08x\n", tp->snd_fack, tp->rcv_numsacks, tp->sack_newdata);
2336 
2337 	/* Skip sackblks, sackhint. */
2338 
2339 	db_print_indent(indent);
2340 	db_printf("t_rttlow: %d   rfbuf_ts: %u   rfbuf_cnt: %d\n",
2341 	    tp->t_rttlow, tp->rfbuf_ts, tp->rfbuf_cnt);
2342 }
2343 
2344 DB_SHOW_COMMAND(tcpcb, db_show_tcpcb)
2345 {
2346 	struct tcpcb *tp;
2347 
2348 	if (!have_addr) {
2349 		db_printf("usage: show tcpcb <addr>\n");
2350 		return;
2351 	}
2352 	tp = (struct tcpcb *)addr;
2353 
2354 	db_print_tcpcb(tp, "tcpcb", 0);
2355 }
2356 #endif
2357