xref: /freebsd/sys/netinet/tcp_usrreq.c (revision 30dfa264d0f2fceddf9814df3fd7461b1a099856)
1 /*-
2  * Copyright (c) 1982, 1986, 1988, 1993
3  *	The Regents of the University of California.
4  * Copyright (c) 2006-2007 Robert N. M. Watson
5  * Copyright (c) 2010-2011 Juniper Networks, Inc.
6  * All rights reserved.
7  *
8  * Portions of this software were developed by Robert N. M. Watson under
9  * contract to Juniper Networks, Inc.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	From: @(#)tcp_usrreq.c	8.2 (Berkeley) 1/3/94
36  */
37 
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include "opt_ddb.h"
42 #include "opt_inet.h"
43 #include "opt_inet6.h"
44 #include "opt_tcpdebug.h"
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/limits.h>
49 #include <sys/malloc.h>
50 #include <sys/refcount.h>
51 #include <sys/kernel.h>
52 #include <sys/sysctl.h>
53 #include <sys/mbuf.h>
54 #ifdef INET6
55 #include <sys/domain.h>
56 #endif /* INET6 */
57 #include <sys/socket.h>
58 #include <sys/socketvar.h>
59 #include <sys/protosw.h>
60 #include <sys/proc.h>
61 #include <sys/jail.h>
62 
63 #ifdef DDB
64 #include <ddb/ddb.h>
65 #endif
66 
67 #include <net/if.h>
68 #include <net/if_var.h>
69 #include <net/route.h>
70 #include <net/vnet.h>
71 
72 #include <netinet/cc.h>
73 #include <netinet/in.h>
74 #include <netinet/in_kdtrace.h>
75 #include <netinet/in_pcb.h>
76 #include <netinet/in_systm.h>
77 #include <netinet/in_var.h>
78 #include <netinet/ip_var.h>
79 #ifdef INET6
80 #include <netinet/ip6.h>
81 #include <netinet6/in6_pcb.h>
82 #include <netinet6/ip6_var.h>
83 #include <netinet6/scope6_var.h>
84 #endif
85 #ifdef TCP_RFC7413
86 #include <netinet/tcp_fastopen.h>
87 #endif
88 #include <netinet/tcp_fsm.h>
89 #include <netinet/tcp_seq.h>
90 #include <netinet/tcp_timer.h>
91 #include <netinet/tcp_var.h>
92 #include <netinet/tcpip.h>
93 #ifdef TCPPCAP
94 #include <netinet/tcp_pcap.h>
95 #endif
96 #ifdef TCPDEBUG
97 #include <netinet/tcp_debug.h>
98 #endif
99 #ifdef TCP_OFFLOAD
100 #include <netinet/tcp_offload.h>
101 #endif
102 
103 /*
104  * TCP protocol interface to socket abstraction.
105  */
106 static int	tcp_attach(struct socket *);
107 #ifdef INET
108 static int	tcp_connect(struct tcpcb *, struct sockaddr *,
109 		    struct thread *td);
110 #endif /* INET */
111 #ifdef INET6
112 static int	tcp6_connect(struct tcpcb *, struct sockaddr *,
113 		    struct thread *td);
114 #endif /* INET6 */
115 static void	tcp_disconnect(struct tcpcb *);
116 static void	tcp_usrclosed(struct tcpcb *);
117 static void	tcp_fill_info(struct tcpcb *, struct tcp_info *);
118 
119 #ifdef TCPDEBUG
120 #define	TCPDEBUG0	int ostate = 0
121 #define	TCPDEBUG1()	ostate = tp ? tp->t_state : 0
122 #define	TCPDEBUG2(req)	if (tp && (so->so_options & SO_DEBUG)) \
123 				tcp_trace(TA_USER, ostate, tp, 0, 0, req)
124 #else
125 #define	TCPDEBUG0
126 #define	TCPDEBUG1()
127 #define	TCPDEBUG2(req)
128 #endif
129 
130 /*
131  * TCP attaches to socket via pru_attach(), reserving space,
132  * and an internet control block.
133  */
134 static int
135 tcp_usr_attach(struct socket *so, int proto, struct thread *td)
136 {
137 	struct inpcb *inp;
138 	struct tcpcb *tp = NULL;
139 	int error;
140 	TCPDEBUG0;
141 
142 	inp = sotoinpcb(so);
143 	KASSERT(inp == NULL, ("tcp_usr_attach: inp != NULL"));
144 	TCPDEBUG1();
145 
146 	error = tcp_attach(so);
147 	if (error)
148 		goto out;
149 
150 	if ((so->so_options & SO_LINGER) && so->so_linger == 0)
151 		so->so_linger = TCP_LINGERTIME;
152 
153 	inp = sotoinpcb(so);
154 	tp = intotcpcb(inp);
155 out:
156 	TCPDEBUG2(PRU_ATTACH);
157 	TCP_PROBE2(debug__user, tp, PRU_ATTACH);
158 	return error;
159 }
160 
161 /*
162  * tcp_detach is called when the socket layer loses its final reference
163  * to the socket, be it a file descriptor reference, a reference from TCP,
164  * etc.  At this point, there is only one case in which we will keep around
165  * inpcb state: time wait.
166  *
167  * This function can probably be re-absorbed back into tcp_usr_detach() now
168  * that there is a single detach path.
169  */
170 static void
171 tcp_detach(struct socket *so, struct inpcb *inp)
172 {
173 	struct tcpcb *tp;
174 
175 	INP_INFO_LOCK_ASSERT(&V_tcbinfo);
176 	INP_WLOCK_ASSERT(inp);
177 
178 	KASSERT(so->so_pcb == inp, ("tcp_detach: so_pcb != inp"));
179 	KASSERT(inp->inp_socket == so, ("tcp_detach: inp_socket != so"));
180 
181 	tp = intotcpcb(inp);
182 
183 	if (inp->inp_flags & INP_TIMEWAIT) {
184 		/*
185 		 * There are two cases to handle: one in which the time wait
186 		 * state is being discarded (INP_DROPPED), and one in which
187 		 * this connection will remain in timewait.  In the former,
188 		 * it is time to discard all state (except tcptw, which has
189 		 * already been discarded by the timewait close code, which
190 		 * should be further up the call stack somewhere).  In the
191 		 * latter case, we detach from the socket, but leave the pcb
192 		 * present until timewait ends.
193 		 *
194 		 * XXXRW: Would it be cleaner to free the tcptw here?
195 		 *
196 		 * Astute question indeed, from twtcp perspective there are
197 		 * three cases to consider:
198 		 *
199 		 * #1 tcp_detach is called at tcptw creation time by
200 		 *  tcp_twstart, then do not discard the newly created tcptw
201 		 *  and leave inpcb present until timewait ends
202 		 * #2 tcp_detach is called at timewait end (or reuse) by
203 		 *  tcp_twclose, then the tcptw has already been discarded
204 		 *  (or reused) and inpcb is freed here
205 		 * #3 tcp_detach is called() after timewait ends (or reuse)
206 		 *  (e.g. by soclose), then tcptw has already been discarded
207 		 *  (or reused) and inpcb is freed here
208 		 *
209 		 *  In all three cases the tcptw should not be freed here.
210 		 */
211 		if (inp->inp_flags & INP_DROPPED) {
212 			KASSERT(tp == NULL, ("tcp_detach: INP_TIMEWAIT && "
213 			    "INP_DROPPED && tp != NULL"));
214 			in_pcbdetach(inp);
215 			in_pcbfree(inp);
216 		} else {
217 			in_pcbdetach(inp);
218 			INP_WUNLOCK(inp);
219 		}
220 	} else {
221 		/*
222 		 * If the connection is not in timewait, we consider two
223 		 * two conditions: one in which no further processing is
224 		 * necessary (dropped || embryonic), and one in which TCP is
225 		 * not yet done, but no longer requires the socket, so the
226 		 * pcb will persist for the time being.
227 		 *
228 		 * XXXRW: Does the second case still occur?
229 		 */
230 		if (inp->inp_flags & INP_DROPPED ||
231 		    tp->t_state < TCPS_SYN_SENT) {
232 			tcp_discardcb(tp);
233 			in_pcbdetach(inp);
234 			in_pcbfree(inp);
235 		} else {
236 			in_pcbdetach(inp);
237 			INP_WUNLOCK(inp);
238 		}
239 	}
240 }
241 
242 /*
243  * pru_detach() detaches the TCP protocol from the socket.
244  * If the protocol state is non-embryonic, then can't
245  * do this directly: have to initiate a pru_disconnect(),
246  * which may finish later; embryonic TCB's can just
247  * be discarded here.
248  */
249 static void
250 tcp_usr_detach(struct socket *so)
251 {
252 	struct inpcb *inp;
253 	int rlock = 0;
254 
255 	inp = sotoinpcb(so);
256 	KASSERT(inp != NULL, ("tcp_usr_detach: inp == NULL"));
257 	if (!INP_INFO_WLOCKED(&V_tcbinfo)) {
258 		INP_INFO_RLOCK(&V_tcbinfo);
259 		rlock = 1;
260 	}
261 	INP_WLOCK(inp);
262 	KASSERT(inp->inp_socket != NULL,
263 	    ("tcp_usr_detach: inp_socket == NULL"));
264 	tcp_detach(so, inp);
265 	if (rlock)
266 		INP_INFO_RUNLOCK(&V_tcbinfo);
267 }
268 
269 #ifdef INET
270 /*
271  * Give the socket an address.
272  */
273 static int
274 tcp_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
275 {
276 	int error = 0;
277 	struct inpcb *inp;
278 	struct tcpcb *tp = NULL;
279 	struct sockaddr_in *sinp;
280 
281 	sinp = (struct sockaddr_in *)nam;
282 	if (nam->sa_len != sizeof (*sinp))
283 		return (EINVAL);
284 	/*
285 	 * Must check for multicast addresses and disallow binding
286 	 * to them.
287 	 */
288 	if (sinp->sin_family == AF_INET &&
289 	    IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
290 		return (EAFNOSUPPORT);
291 
292 	TCPDEBUG0;
293 	inp = sotoinpcb(so);
294 	KASSERT(inp != NULL, ("tcp_usr_bind: inp == NULL"));
295 	INP_WLOCK(inp);
296 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
297 		error = EINVAL;
298 		goto out;
299 	}
300 	tp = intotcpcb(inp);
301 	TCPDEBUG1();
302 	INP_HASH_WLOCK(&V_tcbinfo);
303 	error = in_pcbbind(inp, nam, td->td_ucred);
304 	INP_HASH_WUNLOCK(&V_tcbinfo);
305 out:
306 	TCPDEBUG2(PRU_BIND);
307 	TCP_PROBE2(debug__user, tp, PRU_BIND);
308 	INP_WUNLOCK(inp);
309 
310 	return (error);
311 }
312 #endif /* INET */
313 
314 #ifdef INET6
315 static int
316 tcp6_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
317 {
318 	int error = 0;
319 	struct inpcb *inp;
320 	struct tcpcb *tp = NULL;
321 	struct sockaddr_in6 *sin6p;
322 
323 	sin6p = (struct sockaddr_in6 *)nam;
324 	if (nam->sa_len != sizeof (*sin6p))
325 		return (EINVAL);
326 	/*
327 	 * Must check for multicast addresses and disallow binding
328 	 * to them.
329 	 */
330 	if (sin6p->sin6_family == AF_INET6 &&
331 	    IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
332 		return (EAFNOSUPPORT);
333 
334 	TCPDEBUG0;
335 	inp = sotoinpcb(so);
336 	KASSERT(inp != NULL, ("tcp6_usr_bind: inp == NULL"));
337 	INP_WLOCK(inp);
338 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
339 		error = EINVAL;
340 		goto out;
341 	}
342 	tp = intotcpcb(inp);
343 	TCPDEBUG1();
344 	INP_HASH_WLOCK(&V_tcbinfo);
345 	inp->inp_vflag &= ~INP_IPV4;
346 	inp->inp_vflag |= INP_IPV6;
347 #ifdef INET
348 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
349 		if (IN6_IS_ADDR_UNSPECIFIED(&sin6p->sin6_addr))
350 			inp->inp_vflag |= INP_IPV4;
351 		else if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
352 			struct sockaddr_in sin;
353 
354 			in6_sin6_2_sin(&sin, sin6p);
355 			inp->inp_vflag |= INP_IPV4;
356 			inp->inp_vflag &= ~INP_IPV6;
357 			error = in_pcbbind(inp, (struct sockaddr *)&sin,
358 			    td->td_ucred);
359 			INP_HASH_WUNLOCK(&V_tcbinfo);
360 			goto out;
361 		}
362 	}
363 #endif
364 	error = in6_pcbbind(inp, nam, td->td_ucred);
365 	INP_HASH_WUNLOCK(&V_tcbinfo);
366 out:
367 	TCPDEBUG2(PRU_BIND);
368 	TCP_PROBE2(debug__user, tp, PRU_BIND);
369 	INP_WUNLOCK(inp);
370 	return (error);
371 }
372 #endif /* INET6 */
373 
374 #ifdef INET
375 /*
376  * Prepare to accept connections.
377  */
378 static int
379 tcp_usr_listen(struct socket *so, int backlog, struct thread *td)
380 {
381 	int error = 0;
382 	struct inpcb *inp;
383 	struct tcpcb *tp = NULL;
384 
385 	TCPDEBUG0;
386 	inp = sotoinpcb(so);
387 	KASSERT(inp != NULL, ("tcp_usr_listen: inp == NULL"));
388 	INP_WLOCK(inp);
389 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
390 		error = EINVAL;
391 		goto out;
392 	}
393 	tp = intotcpcb(inp);
394 	TCPDEBUG1();
395 	SOCK_LOCK(so);
396 	error = solisten_proto_check(so);
397 	INP_HASH_WLOCK(&V_tcbinfo);
398 	if (error == 0 && inp->inp_lport == 0)
399 		error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
400 	INP_HASH_WUNLOCK(&V_tcbinfo);
401 	if (error == 0) {
402 		tcp_state_change(tp, TCPS_LISTEN);
403 		solisten_proto(so, backlog);
404 #ifdef TCP_OFFLOAD
405 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
406 			tcp_offload_listen_start(tp);
407 #endif
408 	}
409 	SOCK_UNLOCK(so);
410 
411 #ifdef TCP_RFC7413
412 	if (tp->t_flags & TF_FASTOPEN)
413 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
414 #endif
415 out:
416 	TCPDEBUG2(PRU_LISTEN);
417 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
418 	INP_WUNLOCK(inp);
419 	return (error);
420 }
421 #endif /* INET */
422 
423 #ifdef INET6
424 static int
425 tcp6_usr_listen(struct socket *so, int backlog, struct thread *td)
426 {
427 	int error = 0;
428 	struct inpcb *inp;
429 	struct tcpcb *tp = NULL;
430 
431 	TCPDEBUG0;
432 	inp = sotoinpcb(so);
433 	KASSERT(inp != NULL, ("tcp6_usr_listen: inp == NULL"));
434 	INP_WLOCK(inp);
435 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
436 		error = EINVAL;
437 		goto out;
438 	}
439 	tp = intotcpcb(inp);
440 	TCPDEBUG1();
441 	SOCK_LOCK(so);
442 	error = solisten_proto_check(so);
443 	INP_HASH_WLOCK(&V_tcbinfo);
444 	if (error == 0 && inp->inp_lport == 0) {
445 		inp->inp_vflag &= ~INP_IPV4;
446 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
447 			inp->inp_vflag |= INP_IPV4;
448 		error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
449 	}
450 	INP_HASH_WUNLOCK(&V_tcbinfo);
451 	if (error == 0) {
452 		tcp_state_change(tp, TCPS_LISTEN);
453 		solisten_proto(so, backlog);
454 #ifdef TCP_OFFLOAD
455 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
456 			tcp_offload_listen_start(tp);
457 #endif
458 	}
459 	SOCK_UNLOCK(so);
460 
461 #ifdef TCP_RFC7413
462 	if (tp->t_flags & TF_FASTOPEN)
463 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
464 #endif
465 out:
466 	TCPDEBUG2(PRU_LISTEN);
467 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
468 	INP_WUNLOCK(inp);
469 	return (error);
470 }
471 #endif /* INET6 */
472 
473 #ifdef INET
474 /*
475  * Initiate connection to peer.
476  * Create a template for use in transmissions on this connection.
477  * Enter SYN_SENT state, and mark socket as connecting.
478  * Start keep-alive timer, and seed output sequence space.
479  * Send initial segment on connection.
480  */
481 static int
482 tcp_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
483 {
484 	int error = 0;
485 	struct inpcb *inp;
486 	struct tcpcb *tp = NULL;
487 	struct sockaddr_in *sinp;
488 
489 	sinp = (struct sockaddr_in *)nam;
490 	if (nam->sa_len != sizeof (*sinp))
491 		return (EINVAL);
492 	/*
493 	 * Must disallow TCP ``connections'' to multicast addresses.
494 	 */
495 	if (sinp->sin_family == AF_INET
496 	    && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
497 		return (EAFNOSUPPORT);
498 	if ((error = prison_remote_ip4(td->td_ucred, &sinp->sin_addr)) != 0)
499 		return (error);
500 
501 	TCPDEBUG0;
502 	inp = sotoinpcb(so);
503 	KASSERT(inp != NULL, ("tcp_usr_connect: inp == NULL"));
504 	INP_WLOCK(inp);
505 	if (inp->inp_flags & INP_TIMEWAIT) {
506 		error = EADDRINUSE;
507 		goto out;
508 	}
509 	if (inp->inp_flags & INP_DROPPED) {
510 		error = ECONNREFUSED;
511 		goto out;
512 	}
513 	tp = intotcpcb(inp);
514 	TCPDEBUG1();
515 	if ((error = tcp_connect(tp, nam, td)) != 0)
516 		goto out;
517 #ifdef TCP_OFFLOAD
518 	if (registered_toedevs > 0 &&
519 	    (so->so_options & SO_NO_OFFLOAD) == 0 &&
520 	    (error = tcp_offload_connect(so, nam)) == 0)
521 		goto out;
522 #endif
523 	tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
524 	error = tp->t_fb->tfb_tcp_output(tp);
525 out:
526 	TCPDEBUG2(PRU_CONNECT);
527 	INP_WUNLOCK(inp);
528 	return (error);
529 }
530 #endif /* INET */
531 
532 #ifdef INET6
533 static int
534 tcp6_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
535 {
536 	int error = 0;
537 	struct inpcb *inp;
538 	struct tcpcb *tp = NULL;
539 	struct sockaddr_in6 *sin6p;
540 
541 	TCPDEBUG0;
542 
543 	sin6p = (struct sockaddr_in6 *)nam;
544 	if (nam->sa_len != sizeof (*sin6p))
545 		return (EINVAL);
546 	/*
547 	 * Must disallow TCP ``connections'' to multicast addresses.
548 	 */
549 	if (sin6p->sin6_family == AF_INET6
550 	    && IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
551 		return (EAFNOSUPPORT);
552 
553 	inp = sotoinpcb(so);
554 	KASSERT(inp != NULL, ("tcp6_usr_connect: inp == NULL"));
555 	INP_WLOCK(inp);
556 	if (inp->inp_flags & INP_TIMEWAIT) {
557 		error = EADDRINUSE;
558 		goto out;
559 	}
560 	if (inp->inp_flags & INP_DROPPED) {
561 		error = ECONNREFUSED;
562 		goto out;
563 	}
564 	tp = intotcpcb(inp);
565 	TCPDEBUG1();
566 #ifdef INET
567 	/*
568 	 * XXXRW: Some confusion: V4/V6 flags relate to binding, and
569 	 * therefore probably require the hash lock, which isn't held here.
570 	 * Is this a significant problem?
571 	 */
572 	if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
573 		struct sockaddr_in sin;
574 
575 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
576 			error = EINVAL;
577 			goto out;
578 		}
579 
580 		in6_sin6_2_sin(&sin, sin6p);
581 		inp->inp_vflag |= INP_IPV4;
582 		inp->inp_vflag &= ~INP_IPV6;
583 		if ((error = prison_remote_ip4(td->td_ucred,
584 		    &sin.sin_addr)) != 0)
585 			goto out;
586 		if ((error = tcp_connect(tp, (struct sockaddr *)&sin, td)) != 0)
587 			goto out;
588 #ifdef TCP_OFFLOAD
589 		if (registered_toedevs > 0 &&
590 		    (so->so_options & SO_NO_OFFLOAD) == 0 &&
591 		    (error = tcp_offload_connect(so, nam)) == 0)
592 			goto out;
593 #endif
594 		error = tp->t_fb->tfb_tcp_output(tp);
595 		goto out;
596 	}
597 #endif
598 	inp->inp_vflag &= ~INP_IPV4;
599 	inp->inp_vflag |= INP_IPV6;
600 	inp->inp_inc.inc_flags |= INC_ISIPV6;
601 	if ((error = prison_remote_ip6(td->td_ucred, &sin6p->sin6_addr)) != 0)
602 		goto out;
603 	if ((error = tcp6_connect(tp, nam, td)) != 0)
604 		goto out;
605 #ifdef TCP_OFFLOAD
606 	if (registered_toedevs > 0 &&
607 	    (so->so_options & SO_NO_OFFLOAD) == 0 &&
608 	    (error = tcp_offload_connect(so, nam)) == 0)
609 		goto out;
610 #endif
611 	tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
612 	error = tp->t_fb->tfb_tcp_output(tp);
613 
614 out:
615 	TCPDEBUG2(PRU_CONNECT);
616 	TCP_PROBE2(debug__user, tp, PRU_CONNECT);
617 	INP_WUNLOCK(inp);
618 	return (error);
619 }
620 #endif /* INET6 */
621 
622 /*
623  * Initiate disconnect from peer.
624  * If connection never passed embryonic stage, just drop;
625  * else if don't need to let data drain, then can just drop anyways,
626  * else have to begin TCP shutdown process: mark socket disconnecting,
627  * drain unread data, state switch to reflect user close, and
628  * send segment (e.g. FIN) to peer.  Socket will be really disconnected
629  * when peer sends FIN and acks ours.
630  *
631  * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
632  */
633 static int
634 tcp_usr_disconnect(struct socket *so)
635 {
636 	struct inpcb *inp;
637 	struct tcpcb *tp = NULL;
638 	int error = 0;
639 
640 	TCPDEBUG0;
641 	INP_INFO_RLOCK(&V_tcbinfo);
642 	inp = sotoinpcb(so);
643 	KASSERT(inp != NULL, ("tcp_usr_disconnect: inp == NULL"));
644 	INP_WLOCK(inp);
645 	if (inp->inp_flags & INP_TIMEWAIT)
646 		goto out;
647 	if (inp->inp_flags & INP_DROPPED) {
648 		error = ECONNRESET;
649 		goto out;
650 	}
651 	tp = intotcpcb(inp);
652 	TCPDEBUG1();
653 	tcp_disconnect(tp);
654 out:
655 	TCPDEBUG2(PRU_DISCONNECT);
656 	TCP_PROBE2(debug__user, tp, PRU_DISCONNECT);
657 	INP_WUNLOCK(inp);
658 	INP_INFO_RUNLOCK(&V_tcbinfo);
659 	return (error);
660 }
661 
662 #ifdef INET
663 /*
664  * Accept a connection.  Essentially all the work is done at higher levels;
665  * just return the address of the peer, storing through addr.
666  */
667 static int
668 tcp_usr_accept(struct socket *so, struct sockaddr **nam)
669 {
670 	int error = 0;
671 	struct inpcb *inp = NULL;
672 	struct tcpcb *tp = NULL;
673 	struct in_addr addr;
674 	in_port_t port = 0;
675 	TCPDEBUG0;
676 
677 	if (so->so_state & SS_ISDISCONNECTED)
678 		return (ECONNABORTED);
679 
680 	inp = sotoinpcb(so);
681 	KASSERT(inp != NULL, ("tcp_usr_accept: inp == NULL"));
682 	INP_WLOCK(inp);
683 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
684 		error = ECONNABORTED;
685 		goto out;
686 	}
687 	tp = intotcpcb(inp);
688 	TCPDEBUG1();
689 
690 	/*
691 	 * We inline in_getpeeraddr and COMMON_END here, so that we can
692 	 * copy the data of interest and defer the malloc until after we
693 	 * release the lock.
694 	 */
695 	port = inp->inp_fport;
696 	addr = inp->inp_faddr;
697 
698 out:
699 	TCPDEBUG2(PRU_ACCEPT);
700 	TCP_PROBE2(debug__user, tp, PRU_ACCEPT);
701 	INP_WUNLOCK(inp);
702 	if (error == 0)
703 		*nam = in_sockaddr(port, &addr);
704 	return error;
705 }
706 #endif /* INET */
707 
708 #ifdef INET6
709 static int
710 tcp6_usr_accept(struct socket *so, struct sockaddr **nam)
711 {
712 	struct inpcb *inp = NULL;
713 	int error = 0;
714 	struct tcpcb *tp = NULL;
715 	struct in_addr addr;
716 	struct in6_addr addr6;
717 	in_port_t port = 0;
718 	int v4 = 0;
719 	TCPDEBUG0;
720 
721 	if (so->so_state & SS_ISDISCONNECTED)
722 		return (ECONNABORTED);
723 
724 	inp = sotoinpcb(so);
725 	KASSERT(inp != NULL, ("tcp6_usr_accept: inp == NULL"));
726 	INP_INFO_RLOCK(&V_tcbinfo);
727 	INP_WLOCK(inp);
728 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
729 		error = ECONNABORTED;
730 		goto out;
731 	}
732 	tp = intotcpcb(inp);
733 	TCPDEBUG1();
734 
735 	/*
736 	 * We inline in6_mapped_peeraddr and COMMON_END here, so that we can
737 	 * copy the data of interest and defer the malloc until after we
738 	 * release the lock.
739 	 */
740 	if (inp->inp_vflag & INP_IPV4) {
741 		v4 = 1;
742 		port = inp->inp_fport;
743 		addr = inp->inp_faddr;
744 	} else {
745 		port = inp->inp_fport;
746 		addr6 = inp->in6p_faddr;
747 	}
748 
749 out:
750 	TCPDEBUG2(PRU_ACCEPT);
751 	TCP_PROBE2(debug__user, tp, PRU_ACCEPT);
752 	INP_WUNLOCK(inp);
753 	INP_INFO_RUNLOCK(&V_tcbinfo);
754 	if (error == 0) {
755 		if (v4)
756 			*nam = in6_v4mapsin6_sockaddr(port, &addr);
757 		else
758 			*nam = in6_sockaddr(port, &addr6);
759 	}
760 	return error;
761 }
762 #endif /* INET6 */
763 
764 /*
765  * Mark the connection as being incapable of further output.
766  */
767 static int
768 tcp_usr_shutdown(struct socket *so)
769 {
770 	int error = 0;
771 	struct inpcb *inp;
772 	struct tcpcb *tp = NULL;
773 
774 	TCPDEBUG0;
775 	INP_INFO_RLOCK(&V_tcbinfo);
776 	inp = sotoinpcb(so);
777 	KASSERT(inp != NULL, ("inp == NULL"));
778 	INP_WLOCK(inp);
779 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
780 		error = ECONNRESET;
781 		goto out;
782 	}
783 	tp = intotcpcb(inp);
784 	TCPDEBUG1();
785 	socantsendmore(so);
786 	tcp_usrclosed(tp);
787 	if (!(inp->inp_flags & INP_DROPPED))
788 		error = tp->t_fb->tfb_tcp_output(tp);
789 
790 out:
791 	TCPDEBUG2(PRU_SHUTDOWN);
792 	TCP_PROBE2(debug__user, tp, PRU_SHUTDOWN);
793 	INP_WUNLOCK(inp);
794 	INP_INFO_RUNLOCK(&V_tcbinfo);
795 
796 	return (error);
797 }
798 
799 /*
800  * After a receive, possibly send window update to peer.
801  */
802 static int
803 tcp_usr_rcvd(struct socket *so, int flags)
804 {
805 	struct inpcb *inp;
806 	struct tcpcb *tp = NULL;
807 	int error = 0;
808 
809 	TCPDEBUG0;
810 	inp = sotoinpcb(so);
811 	KASSERT(inp != NULL, ("tcp_usr_rcvd: inp == NULL"));
812 	INP_WLOCK(inp);
813 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
814 		error = ECONNRESET;
815 		goto out;
816 	}
817 	tp = intotcpcb(inp);
818 	TCPDEBUG1();
819 #ifdef TCP_RFC7413
820 	/*
821 	 * For passively-created TFO connections, don't attempt a window
822 	 * update while still in SYN_RECEIVED as this may trigger an early
823 	 * SYN|ACK.  It is preferable to have the SYN|ACK be sent along with
824 	 * application response data, or failing that, when the DELACK timer
825 	 * expires.
826 	 */
827 	if ((tp->t_flags & TF_FASTOPEN) &&
828 	    (tp->t_state == TCPS_SYN_RECEIVED))
829 		goto out;
830 #endif
831 #ifdef TCP_OFFLOAD
832 	if (tp->t_flags & TF_TOE)
833 		tcp_offload_rcvd(tp);
834 	else
835 #endif
836 	tp->t_fb->tfb_tcp_output(tp);
837 
838 out:
839 	TCPDEBUG2(PRU_RCVD);
840 	TCP_PROBE2(debug__user, tp, PRU_RCVD);
841 	INP_WUNLOCK(inp);
842 	return (error);
843 }
844 
845 /*
846  * Do a send by putting data in output queue and updating urgent
847  * marker if URG set.  Possibly send more data.  Unlike the other
848  * pru_*() routines, the mbuf chains are our responsibility.  We
849  * must either enqueue them or free them.  The other pru_* routines
850  * generally are caller-frees.
851  */
852 static int
853 tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
854     struct sockaddr *nam, struct mbuf *control, struct thread *td)
855 {
856 	int error = 0;
857 	struct inpcb *inp;
858 	struct tcpcb *tp = NULL;
859 #ifdef INET6
860 	int isipv6;
861 #endif
862 	TCPDEBUG0;
863 
864 	/*
865 	 * We require the pcbinfo lock if we will close the socket as part of
866 	 * this call.
867 	 */
868 	if (flags & PRUS_EOF)
869 		INP_INFO_RLOCK(&V_tcbinfo);
870 	inp = sotoinpcb(so);
871 	KASSERT(inp != NULL, ("tcp_usr_send: inp == NULL"));
872 	INP_WLOCK(inp);
873 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
874 		if (control)
875 			m_freem(control);
876 		/*
877 		 * In case of PRUS_NOTREADY, tcp_usr_ready() is responsible
878 		 * for freeing memory.
879 		 */
880 		if (m && (flags & PRUS_NOTREADY) == 0)
881 			m_freem(m);
882 		error = ECONNRESET;
883 		goto out;
884 	}
885 #ifdef INET6
886 	isipv6 = nam && nam->sa_family == AF_INET6;
887 #endif /* INET6 */
888 	tp = intotcpcb(inp);
889 	TCPDEBUG1();
890 	if (control) {
891 		/* TCP doesn't do control messages (rights, creds, etc) */
892 		if (control->m_len) {
893 			m_freem(control);
894 			if (m)
895 				m_freem(m);
896 			error = EINVAL;
897 			goto out;
898 		}
899 		m_freem(control);	/* empty control, just free it */
900 	}
901 	if (!(flags & PRUS_OOB)) {
902 		sbappendstream(&so->so_snd, m, flags);
903 		if (nam && tp->t_state < TCPS_SYN_SENT) {
904 			/*
905 			 * Do implied connect if not yet connected,
906 			 * initialize window to default value, and
907 			 * initialize maxseg/maxopd using peer's cached
908 			 * MSS.
909 			 */
910 #ifdef INET6
911 			if (isipv6)
912 				error = tcp6_connect(tp, nam, td);
913 #endif /* INET6 */
914 #if defined(INET6) && defined(INET)
915 			else
916 #endif
917 #ifdef INET
918 				error = tcp_connect(tp, nam, td);
919 #endif
920 			if (error)
921 				goto out;
922 			tp->snd_wnd = TTCP_CLIENT_SND_WND;
923 			tcp_mss(tp, -1);
924 		}
925 		if (flags & PRUS_EOF) {
926 			/*
927 			 * Close the send side of the connection after
928 			 * the data is sent.
929 			 */
930 			INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
931 			socantsendmore(so);
932 			tcp_usrclosed(tp);
933 		}
934 		if (!(inp->inp_flags & INP_DROPPED) &&
935 		    !(flags & PRUS_NOTREADY)) {
936 			if (flags & PRUS_MORETOCOME)
937 				tp->t_flags |= TF_MORETOCOME;
938 			error = tp->t_fb->tfb_tcp_output(tp);
939 			if (flags & PRUS_MORETOCOME)
940 				tp->t_flags &= ~TF_MORETOCOME;
941 		}
942 	} else {
943 		/*
944 		 * XXXRW: PRUS_EOF not implemented with PRUS_OOB?
945 		 */
946 		SOCKBUF_LOCK(&so->so_snd);
947 		if (sbspace(&so->so_snd) < -512) {
948 			SOCKBUF_UNLOCK(&so->so_snd);
949 			m_freem(m);
950 			error = ENOBUFS;
951 			goto out;
952 		}
953 		/*
954 		 * According to RFC961 (Assigned Protocols),
955 		 * the urgent pointer points to the last octet
956 		 * of urgent data.  We continue, however,
957 		 * to consider it to indicate the first octet
958 		 * of data past the urgent section.
959 		 * Otherwise, snd_up should be one lower.
960 		 */
961 		sbappendstream_locked(&so->so_snd, m, flags);
962 		SOCKBUF_UNLOCK(&so->so_snd);
963 		if (nam && tp->t_state < TCPS_SYN_SENT) {
964 			/*
965 			 * Do implied connect if not yet connected,
966 			 * initialize window to default value, and
967 			 * initialize maxseg/maxopd using peer's cached
968 			 * MSS.
969 			 */
970 #ifdef INET6
971 			if (isipv6)
972 				error = tcp6_connect(tp, nam, td);
973 #endif /* INET6 */
974 #if defined(INET6) && defined(INET)
975 			else
976 #endif
977 #ifdef INET
978 				error = tcp_connect(tp, nam, td);
979 #endif
980 			if (error)
981 				goto out;
982 			tp->snd_wnd = TTCP_CLIENT_SND_WND;
983 			tcp_mss(tp, -1);
984 		}
985 		tp->snd_up = tp->snd_una + sbavail(&so->so_snd);
986 		if (!(flags & PRUS_NOTREADY)) {
987 			tp->t_flags |= TF_FORCEDATA;
988 			error = tp->t_fb->tfb_tcp_output(tp);
989 			tp->t_flags &= ~TF_FORCEDATA;
990 		}
991 	}
992 out:
993 	TCPDEBUG2((flags & PRUS_OOB) ? PRU_SENDOOB :
994 		  ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
995 	TCP_PROBE2(debug__user, tp, (flags & PRUS_OOB) ? PRU_SENDOOB :
996 		   ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
997 	INP_WUNLOCK(inp);
998 	if (flags & PRUS_EOF)
999 		INP_INFO_RUNLOCK(&V_tcbinfo);
1000 	return (error);
1001 }
1002 
1003 static int
1004 tcp_usr_ready(struct socket *so, struct mbuf *m, int count)
1005 {
1006 	struct inpcb *inp;
1007 	struct tcpcb *tp;
1008 	int error;
1009 
1010 	inp = sotoinpcb(so);
1011 	INP_WLOCK(inp);
1012 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1013 		INP_WUNLOCK(inp);
1014 		for (int i = 0; i < count; i++)
1015 			m = m_free(m);
1016 		return (ECONNRESET);
1017 	}
1018 	tp = intotcpcb(inp);
1019 
1020 	SOCKBUF_LOCK(&so->so_snd);
1021 	error = sbready(&so->so_snd, m, count);
1022 	SOCKBUF_UNLOCK(&so->so_snd);
1023 	if (error == 0)
1024 		error = tp->t_fb->tfb_tcp_output(tp);
1025 	INP_WUNLOCK(inp);
1026 
1027 	return (error);
1028 }
1029 
1030 /*
1031  * Abort the TCP.  Drop the connection abruptly.
1032  */
1033 static void
1034 tcp_usr_abort(struct socket *so)
1035 {
1036 	struct inpcb *inp;
1037 	struct tcpcb *tp = NULL;
1038 	TCPDEBUG0;
1039 
1040 	inp = sotoinpcb(so);
1041 	KASSERT(inp != NULL, ("tcp_usr_abort: inp == NULL"));
1042 
1043 	INP_INFO_RLOCK(&V_tcbinfo);
1044 	INP_WLOCK(inp);
1045 	KASSERT(inp->inp_socket != NULL,
1046 	    ("tcp_usr_abort: inp_socket == NULL"));
1047 
1048 	/*
1049 	 * If we still have full TCP state, and we're not dropped, drop.
1050 	 */
1051 	if (!(inp->inp_flags & INP_TIMEWAIT) &&
1052 	    !(inp->inp_flags & INP_DROPPED)) {
1053 		tp = intotcpcb(inp);
1054 		TCPDEBUG1();
1055 		tcp_drop(tp, ECONNABORTED);
1056 		TCPDEBUG2(PRU_ABORT);
1057 		TCP_PROBE2(debug__user, tp, PRU_ABORT);
1058 	}
1059 	if (!(inp->inp_flags & INP_DROPPED)) {
1060 		SOCK_LOCK(so);
1061 		so->so_state |= SS_PROTOREF;
1062 		SOCK_UNLOCK(so);
1063 		inp->inp_flags |= INP_SOCKREF;
1064 	}
1065 	INP_WUNLOCK(inp);
1066 	INP_INFO_RUNLOCK(&V_tcbinfo);
1067 }
1068 
1069 /*
1070  * TCP socket is closed.  Start friendly disconnect.
1071  */
1072 static void
1073 tcp_usr_close(struct socket *so)
1074 {
1075 	struct inpcb *inp;
1076 	struct tcpcb *tp = NULL;
1077 	TCPDEBUG0;
1078 
1079 	inp = sotoinpcb(so);
1080 	KASSERT(inp != NULL, ("tcp_usr_close: inp == NULL"));
1081 
1082 	INP_INFO_RLOCK(&V_tcbinfo);
1083 	INP_WLOCK(inp);
1084 	KASSERT(inp->inp_socket != NULL,
1085 	    ("tcp_usr_close: inp_socket == NULL"));
1086 
1087 	/*
1088 	 * If we still have full TCP state, and we're not dropped, initiate
1089 	 * a disconnect.
1090 	 */
1091 	if (!(inp->inp_flags & INP_TIMEWAIT) &&
1092 	    !(inp->inp_flags & INP_DROPPED)) {
1093 		tp = intotcpcb(inp);
1094 		TCPDEBUG1();
1095 		tcp_disconnect(tp);
1096 		TCPDEBUG2(PRU_CLOSE);
1097 		TCP_PROBE2(debug__user, tp, PRU_CLOSE);
1098 	}
1099 	if (!(inp->inp_flags & INP_DROPPED)) {
1100 		SOCK_LOCK(so);
1101 		so->so_state |= SS_PROTOREF;
1102 		SOCK_UNLOCK(so);
1103 		inp->inp_flags |= INP_SOCKREF;
1104 	}
1105 	INP_WUNLOCK(inp);
1106 	INP_INFO_RUNLOCK(&V_tcbinfo);
1107 }
1108 
1109 /*
1110  * Receive out-of-band data.
1111  */
1112 static int
1113 tcp_usr_rcvoob(struct socket *so, struct mbuf *m, int flags)
1114 {
1115 	int error = 0;
1116 	struct inpcb *inp;
1117 	struct tcpcb *tp = NULL;
1118 
1119 	TCPDEBUG0;
1120 	inp = sotoinpcb(so);
1121 	KASSERT(inp != NULL, ("tcp_usr_rcvoob: inp == NULL"));
1122 	INP_WLOCK(inp);
1123 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1124 		error = ECONNRESET;
1125 		goto out;
1126 	}
1127 	tp = intotcpcb(inp);
1128 	TCPDEBUG1();
1129 	if ((so->so_oobmark == 0 &&
1130 	     (so->so_rcv.sb_state & SBS_RCVATMARK) == 0) ||
1131 	    so->so_options & SO_OOBINLINE ||
1132 	    tp->t_oobflags & TCPOOB_HADDATA) {
1133 		error = EINVAL;
1134 		goto out;
1135 	}
1136 	if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
1137 		error = EWOULDBLOCK;
1138 		goto out;
1139 	}
1140 	m->m_len = 1;
1141 	*mtod(m, caddr_t) = tp->t_iobc;
1142 	if ((flags & MSG_PEEK) == 0)
1143 		tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
1144 
1145 out:
1146 	TCPDEBUG2(PRU_RCVOOB);
1147 	TCP_PROBE2(debug__user, tp, PRU_RCVOOB);
1148 	INP_WUNLOCK(inp);
1149 	return (error);
1150 }
1151 
1152 #ifdef INET
1153 struct pr_usrreqs tcp_usrreqs = {
1154 	.pru_abort =		tcp_usr_abort,
1155 	.pru_accept =		tcp_usr_accept,
1156 	.pru_attach =		tcp_usr_attach,
1157 	.pru_bind =		tcp_usr_bind,
1158 	.pru_connect =		tcp_usr_connect,
1159 	.pru_control =		in_control,
1160 	.pru_detach =		tcp_usr_detach,
1161 	.pru_disconnect =	tcp_usr_disconnect,
1162 	.pru_listen =		tcp_usr_listen,
1163 	.pru_peeraddr =		in_getpeeraddr,
1164 	.pru_rcvd =		tcp_usr_rcvd,
1165 	.pru_rcvoob =		tcp_usr_rcvoob,
1166 	.pru_send =		tcp_usr_send,
1167 	.pru_ready =		tcp_usr_ready,
1168 	.pru_shutdown =		tcp_usr_shutdown,
1169 	.pru_sockaddr =		in_getsockaddr,
1170 	.pru_sosetlabel =	in_pcbsosetlabel,
1171 	.pru_close =		tcp_usr_close,
1172 };
1173 #endif /* INET */
1174 
1175 #ifdef INET6
1176 struct pr_usrreqs tcp6_usrreqs = {
1177 	.pru_abort =		tcp_usr_abort,
1178 	.pru_accept =		tcp6_usr_accept,
1179 	.pru_attach =		tcp_usr_attach,
1180 	.pru_bind =		tcp6_usr_bind,
1181 	.pru_connect =		tcp6_usr_connect,
1182 	.pru_control =		in6_control,
1183 	.pru_detach =		tcp_usr_detach,
1184 	.pru_disconnect =	tcp_usr_disconnect,
1185 	.pru_listen =		tcp6_usr_listen,
1186 	.pru_peeraddr =		in6_mapped_peeraddr,
1187 	.pru_rcvd =		tcp_usr_rcvd,
1188 	.pru_rcvoob =		tcp_usr_rcvoob,
1189 	.pru_send =		tcp_usr_send,
1190 	.pru_ready =		tcp_usr_ready,
1191 	.pru_shutdown =		tcp_usr_shutdown,
1192 	.pru_sockaddr =		in6_mapped_sockaddr,
1193 	.pru_sosetlabel =	in_pcbsosetlabel,
1194 	.pru_close =		tcp_usr_close,
1195 };
1196 #endif /* INET6 */
1197 
1198 #ifdef INET
1199 /*
1200  * Common subroutine to open a TCP connection to remote host specified
1201  * by struct sockaddr_in in mbuf *nam.  Call in_pcbbind to assign a local
1202  * port number if needed.  Call in_pcbconnect_setup to do the routing and
1203  * to choose a local host address (interface).  If there is an existing
1204  * incarnation of the same connection in TIME-WAIT state and if the remote
1205  * host was sending CC options and if the connection duration was < MSL, then
1206  * truncate the previous TIME-WAIT state and proceed.
1207  * Initialize connection parameters and enter SYN-SENT state.
1208  */
1209 static int
1210 tcp_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
1211 {
1212 	struct inpcb *inp = tp->t_inpcb, *oinp;
1213 	struct socket *so = inp->inp_socket;
1214 	struct in_addr laddr;
1215 	u_short lport;
1216 	int error;
1217 
1218 	INP_WLOCK_ASSERT(inp);
1219 	INP_HASH_WLOCK(&V_tcbinfo);
1220 
1221 	if (inp->inp_lport == 0) {
1222 		error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
1223 		if (error)
1224 			goto out;
1225 	}
1226 
1227 	/*
1228 	 * Cannot simply call in_pcbconnect, because there might be an
1229 	 * earlier incarnation of this same connection still in
1230 	 * TIME_WAIT state, creating an ADDRINUSE error.
1231 	 */
1232 	laddr = inp->inp_laddr;
1233 	lport = inp->inp_lport;
1234 	error = in_pcbconnect_setup(inp, nam, &laddr.s_addr, &lport,
1235 	    &inp->inp_faddr.s_addr, &inp->inp_fport, &oinp, td->td_ucred);
1236 	if (error && oinp == NULL)
1237 		goto out;
1238 	if (oinp) {
1239 		error = EADDRINUSE;
1240 		goto out;
1241 	}
1242 	inp->inp_laddr = laddr;
1243 	in_pcbrehash(inp);
1244 	INP_HASH_WUNLOCK(&V_tcbinfo);
1245 
1246 	/*
1247 	 * Compute window scaling to request:
1248 	 * Scale to fit into sweet spot.  See tcp_syncache.c.
1249 	 * XXX: This should move to tcp_output().
1250 	 */
1251 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1252 	    (TCP_MAXWIN << tp->request_r_scale) < sb_max)
1253 		tp->request_r_scale++;
1254 
1255 	soisconnecting(so);
1256 	TCPSTAT_INC(tcps_connattempt);
1257 	tcp_state_change(tp, TCPS_SYN_SENT);
1258 	tp->iss = tcp_new_isn(tp);
1259 	tcp_sendseqinit(tp);
1260 
1261 	return 0;
1262 
1263 out:
1264 	INP_HASH_WUNLOCK(&V_tcbinfo);
1265 	return (error);
1266 }
1267 #endif /* INET */
1268 
1269 #ifdef INET6
1270 static int
1271 tcp6_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
1272 {
1273 	struct inpcb *inp = tp->t_inpcb;
1274 	int error;
1275 
1276 	INP_WLOCK_ASSERT(inp);
1277 	INP_HASH_WLOCK(&V_tcbinfo);
1278 
1279 	if (inp->inp_lport == 0) {
1280 		error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
1281 		if (error)
1282 			goto out;
1283 	}
1284 	error = in6_pcbconnect(inp, nam, td->td_ucred);
1285 	if (error != 0)
1286 		goto out;
1287 	INP_HASH_WUNLOCK(&V_tcbinfo);
1288 
1289 	/* Compute window scaling to request.  */
1290 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1291 	    (TCP_MAXWIN << tp->request_r_scale) < sb_max)
1292 		tp->request_r_scale++;
1293 
1294 	soisconnecting(inp->inp_socket);
1295 	TCPSTAT_INC(tcps_connattempt);
1296 	tcp_state_change(tp, TCPS_SYN_SENT);
1297 	tp->iss = tcp_new_isn(tp);
1298 	tcp_sendseqinit(tp);
1299 
1300 	return 0;
1301 
1302 out:
1303 	INP_HASH_WUNLOCK(&V_tcbinfo);
1304 	return error;
1305 }
1306 #endif /* INET6 */
1307 
1308 /*
1309  * Export TCP internal state information via a struct tcp_info, based on the
1310  * Linux 2.6 API.  Not ABI compatible as our constants are mapped differently
1311  * (TCP state machine, etc).  We export all information using FreeBSD-native
1312  * constants -- for example, the numeric values for tcpi_state will differ
1313  * from Linux.
1314  */
1315 static void
1316 tcp_fill_info(struct tcpcb *tp, struct tcp_info *ti)
1317 {
1318 
1319 	INP_WLOCK_ASSERT(tp->t_inpcb);
1320 	bzero(ti, sizeof(*ti));
1321 
1322 	ti->tcpi_state = tp->t_state;
1323 	if ((tp->t_flags & TF_REQ_TSTMP) && (tp->t_flags & TF_RCVD_TSTMP))
1324 		ti->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1325 	if (tp->t_flags & TF_SACK_PERMIT)
1326 		ti->tcpi_options |= TCPI_OPT_SACK;
1327 	if ((tp->t_flags & TF_REQ_SCALE) && (tp->t_flags & TF_RCVD_SCALE)) {
1328 		ti->tcpi_options |= TCPI_OPT_WSCALE;
1329 		ti->tcpi_snd_wscale = tp->snd_scale;
1330 		ti->tcpi_rcv_wscale = tp->rcv_scale;
1331 	}
1332 
1333 	ti->tcpi_rto = tp->t_rxtcur * tick;
1334 	ti->tcpi_last_data_recv = (long)(ticks - (int)tp->t_rcvtime) * tick;
1335 	ti->tcpi_rtt = ((u_int64_t)tp->t_srtt * tick) >> TCP_RTT_SHIFT;
1336 	ti->tcpi_rttvar = ((u_int64_t)tp->t_rttvar * tick) >> TCP_RTTVAR_SHIFT;
1337 
1338 	ti->tcpi_snd_ssthresh = tp->snd_ssthresh;
1339 	ti->tcpi_snd_cwnd = tp->snd_cwnd;
1340 
1341 	/*
1342 	 * FreeBSD-specific extension fields for tcp_info.
1343 	 */
1344 	ti->tcpi_rcv_space = tp->rcv_wnd;
1345 	ti->tcpi_rcv_nxt = tp->rcv_nxt;
1346 	ti->tcpi_snd_wnd = tp->snd_wnd;
1347 	ti->tcpi_snd_bwnd = 0;		/* Unused, kept for compat. */
1348 	ti->tcpi_snd_nxt = tp->snd_nxt;
1349 	ti->tcpi_snd_mss = tp->t_maxseg;
1350 	ti->tcpi_rcv_mss = tp->t_maxseg;
1351 	if (tp->t_flags & TF_TOE)
1352 		ti->tcpi_options |= TCPI_OPT_TOE;
1353 	ti->tcpi_snd_rexmitpack = tp->t_sndrexmitpack;
1354 	ti->tcpi_rcv_ooopack = tp->t_rcvoopack;
1355 	ti->tcpi_snd_zerowin = tp->t_sndzerowin;
1356 }
1357 
1358 /*
1359  * tcp_ctloutput() must drop the inpcb lock before performing copyin on
1360  * socket option arguments.  When it re-acquires the lock after the copy, it
1361  * has to revalidate that the connection is still valid for the socket
1362  * option.
1363  */
1364 #define INP_WLOCK_RECHECK(inp) do {					\
1365 	INP_WLOCK(inp);							\
1366 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {		\
1367 		INP_WUNLOCK(inp);					\
1368 		return (ECONNRESET);					\
1369 	}								\
1370 	tp = intotcpcb(inp);						\
1371 } while(0)
1372 
1373 int
1374 tcp_ctloutput(struct socket *so, struct sockopt *sopt)
1375 {
1376 	int	error;
1377 	struct	inpcb *inp;
1378 	struct	tcpcb *tp;
1379 	struct tcp_function_block *blk;
1380 	struct tcp_function_set fsn;
1381 
1382 	error = 0;
1383 	inp = sotoinpcb(so);
1384 	KASSERT(inp != NULL, ("tcp_ctloutput: inp == NULL"));
1385 	INP_WLOCK(inp);
1386 	if (sopt->sopt_level != IPPROTO_TCP) {
1387 #ifdef INET6
1388 		if (inp->inp_vflag & INP_IPV6PROTO) {
1389 			INP_WUNLOCK(inp);
1390 			error = ip6_ctloutput(so, sopt);
1391 		}
1392 #endif /* INET6 */
1393 #if defined(INET6) && defined(INET)
1394 		else
1395 #endif
1396 #ifdef INET
1397 		{
1398 			INP_WUNLOCK(inp);
1399 			error = ip_ctloutput(so, sopt);
1400 		}
1401 #endif
1402 		return (error);
1403 	}
1404 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1405 		INP_WUNLOCK(inp);
1406 		return (ECONNRESET);
1407 	}
1408 	tp = intotcpcb(inp);
1409 	/*
1410 	 * Protect the TCP option TCP_FUNCTION_BLK so
1411 	 * that a sub-function can *never* overwrite this.
1412 	 */
1413 	if ((sopt->sopt_dir == SOPT_SET) &&
1414 	    (sopt->sopt_name == TCP_FUNCTION_BLK)) {
1415 		INP_WUNLOCK(inp);
1416 		error = sooptcopyin(sopt, &fsn, sizeof fsn,
1417 		    sizeof fsn);
1418 		if (error)
1419 			return (error);
1420 		INP_WLOCK_RECHECK(inp);
1421 		if (tp->t_state != TCPS_CLOSED) {
1422 			/*
1423 			 * The user has advanced the state
1424 			 * past the initial point, we can't
1425 			 * switch since we are down the road
1426 			 * and a new set of functions may
1427 			 * not be compatibile.
1428 			 */
1429 			INP_WUNLOCK(inp);
1430 			return(EINVAL);
1431 		}
1432 		blk = find_and_ref_tcp_functions(&fsn);
1433 		if (blk == NULL) {
1434 			INP_WUNLOCK(inp);
1435 			return (ENOENT);
1436 		}
1437 		if (tp->t_fb != blk) {
1438 			if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
1439 				refcount_release(&blk->tfb_refcnt);
1440 				INP_WUNLOCK(inp);
1441 				return (ENOENT);
1442 			}
1443 			/*
1444 			 * Release the old refcnt, the
1445 			 * lookup acquires a ref on the
1446 			 * new one.
1447 			 */
1448 			if (tp->t_fb->tfb_tcp_fb_fini)
1449 				(*tp->t_fb->tfb_tcp_fb_fini)(tp);
1450 			refcount_release(&tp->t_fb->tfb_refcnt);
1451 			tp->t_fb = blk;
1452 			if (tp->t_fb->tfb_tcp_fb_init) {
1453 				(*tp->t_fb->tfb_tcp_fb_init)(tp);
1454 			}
1455 		}
1456 #ifdef TCP_OFFLOAD
1457 		if (tp->t_flags & TF_TOE) {
1458 			tcp_offload_ctloutput(tp, sopt->sopt_dir,
1459 			     sopt->sopt_name);
1460 		}
1461 #endif
1462 		INP_WUNLOCK(inp);
1463 		return (error);
1464 	} else if ((sopt->sopt_dir == SOPT_GET) &&
1465 	    (sopt->sopt_name == TCP_FUNCTION_BLK)) {
1466 		strcpy(fsn.function_set_name, tp->t_fb->tfb_tcp_block_name);
1467 		fsn.pcbcnt = tp->t_fb->tfb_refcnt;
1468 		INP_WUNLOCK(inp);
1469 		error = sooptcopyout(sopt, &fsn, sizeof fsn);
1470 		return (error);
1471 	}
1472 	/* Pass in the INP locked, called must unlock it */
1473 	return (tp->t_fb->tfb_tcp_ctloutput(so, sopt, inp, tp));
1474 }
1475 
1476 int
1477 tcp_default_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp)
1478 {
1479 	int	error, opt, optval;
1480 	u_int	ui;
1481 	struct	tcp_info ti;
1482 	struct cc_algo *algo;
1483 	char buf[TCP_CA_NAME_MAX];
1484 
1485 	switch (sopt->sopt_dir) {
1486 	case SOPT_SET:
1487 		switch (sopt->sopt_name) {
1488 #ifdef TCP_SIGNATURE
1489 		case TCP_MD5SIG:
1490 			INP_WUNLOCK(inp);
1491 			error = sooptcopyin(sopt, &optval, sizeof optval,
1492 			    sizeof optval);
1493 			if (error)
1494 				return (error);
1495 
1496 			INP_WLOCK_RECHECK(inp);
1497 			if (optval > 0)
1498 				tp->t_flags |= TF_SIGNATURE;
1499 			else
1500 				tp->t_flags &= ~TF_SIGNATURE;
1501 			goto unlock_and_done;
1502 #endif /* TCP_SIGNATURE */
1503 
1504 		case TCP_NODELAY:
1505 		case TCP_NOOPT:
1506 			INP_WUNLOCK(inp);
1507 			error = sooptcopyin(sopt, &optval, sizeof optval,
1508 			    sizeof optval);
1509 			if (error)
1510 				return (error);
1511 
1512 			INP_WLOCK_RECHECK(inp);
1513 			switch (sopt->sopt_name) {
1514 			case TCP_NODELAY:
1515 				opt = TF_NODELAY;
1516 				break;
1517 			case TCP_NOOPT:
1518 				opt = TF_NOOPT;
1519 				break;
1520 			default:
1521 				opt = 0; /* dead code to fool gcc */
1522 				break;
1523 			}
1524 
1525 			if (optval)
1526 				tp->t_flags |= opt;
1527 			else
1528 				tp->t_flags &= ~opt;
1529 unlock_and_done:
1530 #ifdef TCP_OFFLOAD
1531 			if (tp->t_flags & TF_TOE) {
1532 				tcp_offload_ctloutput(tp, sopt->sopt_dir,
1533 				    sopt->sopt_name);
1534 			}
1535 #endif
1536 			INP_WUNLOCK(inp);
1537 			break;
1538 
1539 		case TCP_NOPUSH:
1540 			INP_WUNLOCK(inp);
1541 			error = sooptcopyin(sopt, &optval, sizeof optval,
1542 			    sizeof optval);
1543 			if (error)
1544 				return (error);
1545 
1546 			INP_WLOCK_RECHECK(inp);
1547 			if (optval)
1548 				tp->t_flags |= TF_NOPUSH;
1549 			else if (tp->t_flags & TF_NOPUSH) {
1550 				tp->t_flags &= ~TF_NOPUSH;
1551 				if (TCPS_HAVEESTABLISHED(tp->t_state))
1552 					error = tp->t_fb->tfb_tcp_output(tp);
1553 			}
1554 			goto unlock_and_done;
1555 
1556 		case TCP_MAXSEG:
1557 			INP_WUNLOCK(inp);
1558 			error = sooptcopyin(sopt, &optval, sizeof optval,
1559 			    sizeof optval);
1560 			if (error)
1561 				return (error);
1562 
1563 			INP_WLOCK_RECHECK(inp);
1564 			if (optval > 0 && optval <= tp->t_maxseg &&
1565 			    optval + 40 >= V_tcp_minmss)
1566 				tp->t_maxseg = optval;
1567 			else
1568 				error = EINVAL;
1569 			goto unlock_and_done;
1570 
1571 		case TCP_INFO:
1572 			INP_WUNLOCK(inp);
1573 			error = EINVAL;
1574 			break;
1575 
1576 		case TCP_CONGESTION:
1577 			INP_WUNLOCK(inp);
1578 			bzero(buf, sizeof(buf));
1579 			error = sooptcopyin(sopt, &buf, sizeof(buf), 1);
1580 			if (error)
1581 				break;
1582 			INP_WLOCK_RECHECK(inp);
1583 			/*
1584 			 * Return EINVAL if we can't find the requested cc algo.
1585 			 */
1586 			error = EINVAL;
1587 			CC_LIST_RLOCK();
1588 			STAILQ_FOREACH(algo, &cc_list, entries) {
1589 				if (strncmp(buf, algo->name, TCP_CA_NAME_MAX)
1590 				    == 0) {
1591 					/* We've found the requested algo. */
1592 					error = 0;
1593 					/*
1594 					 * We hold a write lock over the tcb
1595 					 * so it's safe to do these things
1596 					 * without ordering concerns.
1597 					 */
1598 					if (CC_ALGO(tp)->cb_destroy != NULL)
1599 						CC_ALGO(tp)->cb_destroy(tp->ccv);
1600 					CC_ALGO(tp) = algo;
1601 					/*
1602 					 * If something goes pear shaped
1603 					 * initialising the new algo,
1604 					 * fall back to newreno (which
1605 					 * does not require initialisation).
1606 					 */
1607 					if (algo->cb_init != NULL)
1608 						if (algo->cb_init(tp->ccv) > 0) {
1609 							CC_ALGO(tp) = &newreno_cc_algo;
1610 							/*
1611 							 * The only reason init
1612 							 * should fail is
1613 							 * because of malloc.
1614 							 */
1615 							error = ENOMEM;
1616 						}
1617 					break; /* Break the STAILQ_FOREACH. */
1618 				}
1619 			}
1620 			CC_LIST_RUNLOCK();
1621 			goto unlock_and_done;
1622 
1623 		case TCP_KEEPIDLE:
1624 		case TCP_KEEPINTVL:
1625 		case TCP_KEEPINIT:
1626 			INP_WUNLOCK(inp);
1627 			error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
1628 			if (error)
1629 				return (error);
1630 
1631 			if (ui > (UINT_MAX / hz)) {
1632 				error = EINVAL;
1633 				break;
1634 			}
1635 			ui *= hz;
1636 
1637 			INP_WLOCK_RECHECK(inp);
1638 			switch (sopt->sopt_name) {
1639 			case TCP_KEEPIDLE:
1640 				tp->t_keepidle = ui;
1641 				/*
1642 				 * XXX: better check current remaining
1643 				 * timeout and "merge" it with new value.
1644 				 */
1645 				if ((tp->t_state > TCPS_LISTEN) &&
1646 				    (tp->t_state <= TCPS_CLOSING))
1647 					tcp_timer_activate(tp, TT_KEEP,
1648 					    TP_KEEPIDLE(tp));
1649 				break;
1650 			case TCP_KEEPINTVL:
1651 				tp->t_keepintvl = ui;
1652 				if ((tp->t_state == TCPS_FIN_WAIT_2) &&
1653 				    (TP_MAXIDLE(tp) > 0))
1654 					tcp_timer_activate(tp, TT_2MSL,
1655 					    TP_MAXIDLE(tp));
1656 				break;
1657 			case TCP_KEEPINIT:
1658 				tp->t_keepinit = ui;
1659 				if (tp->t_state == TCPS_SYN_RECEIVED ||
1660 				    tp->t_state == TCPS_SYN_SENT)
1661 					tcp_timer_activate(tp, TT_KEEP,
1662 					    TP_KEEPINIT(tp));
1663 				break;
1664 			}
1665 			goto unlock_and_done;
1666 
1667 		case TCP_KEEPCNT:
1668 			INP_WUNLOCK(inp);
1669 			error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
1670 			if (error)
1671 				return (error);
1672 
1673 			INP_WLOCK_RECHECK(inp);
1674 			tp->t_keepcnt = ui;
1675 			if ((tp->t_state == TCPS_FIN_WAIT_2) &&
1676 			    (TP_MAXIDLE(tp) > 0))
1677 				tcp_timer_activate(tp, TT_2MSL,
1678 				    TP_MAXIDLE(tp));
1679 			goto unlock_and_done;
1680 
1681 #ifdef TCPPCAP
1682 		case TCP_PCAP_OUT:
1683 		case TCP_PCAP_IN:
1684 			INP_WUNLOCK(inp);
1685 			error = sooptcopyin(sopt, &optval, sizeof optval,
1686 			    sizeof optval);
1687 			if (error)
1688 				return (error);
1689 
1690 			INP_WLOCK_RECHECK(inp);
1691 			if (optval >= 0)
1692 				tcp_pcap_set_sock_max(TCP_PCAP_OUT ?
1693 					&(tp->t_outpkts) : &(tp->t_inpkts),
1694 					optval);
1695 			else
1696 				error = EINVAL;
1697 			goto unlock_and_done;
1698 #endif
1699 
1700 #ifdef TCP_RFC7413
1701 		case TCP_FASTOPEN:
1702 			INP_WUNLOCK(inp);
1703 			if (!V_tcp_fastopen_enabled)
1704 				return (EPERM);
1705 
1706 			error = sooptcopyin(sopt, &optval, sizeof optval,
1707 			    sizeof optval);
1708 			if (error)
1709 				return (error);
1710 
1711 			INP_WLOCK_RECHECK(inp);
1712 			if (optval) {
1713 				tp->t_flags |= TF_FASTOPEN;
1714 				if ((tp->t_state == TCPS_LISTEN) &&
1715 				    (tp->t_tfo_pending == NULL))
1716 					tp->t_tfo_pending =
1717 					    tcp_fastopen_alloc_counter();
1718 			} else
1719 				tp->t_flags &= ~TF_FASTOPEN;
1720 			goto unlock_and_done;
1721 #endif
1722 
1723 		default:
1724 			INP_WUNLOCK(inp);
1725 			error = ENOPROTOOPT;
1726 			break;
1727 		}
1728 		break;
1729 
1730 	case SOPT_GET:
1731 		tp = intotcpcb(inp);
1732 		switch (sopt->sopt_name) {
1733 #ifdef TCP_SIGNATURE
1734 		case TCP_MD5SIG:
1735 			optval = (tp->t_flags & TF_SIGNATURE) ? 1 : 0;
1736 			INP_WUNLOCK(inp);
1737 			error = sooptcopyout(sopt, &optval, sizeof optval);
1738 			break;
1739 #endif
1740 
1741 		case TCP_NODELAY:
1742 			optval = tp->t_flags & TF_NODELAY;
1743 			INP_WUNLOCK(inp);
1744 			error = sooptcopyout(sopt, &optval, sizeof optval);
1745 			break;
1746 		case TCP_MAXSEG:
1747 			optval = tp->t_maxseg;
1748 			INP_WUNLOCK(inp);
1749 			error = sooptcopyout(sopt, &optval, sizeof optval);
1750 			break;
1751 		case TCP_NOOPT:
1752 			optval = tp->t_flags & TF_NOOPT;
1753 			INP_WUNLOCK(inp);
1754 			error = sooptcopyout(sopt, &optval, sizeof optval);
1755 			break;
1756 		case TCP_NOPUSH:
1757 			optval = tp->t_flags & TF_NOPUSH;
1758 			INP_WUNLOCK(inp);
1759 			error = sooptcopyout(sopt, &optval, sizeof optval);
1760 			break;
1761 		case TCP_INFO:
1762 			tcp_fill_info(tp, &ti);
1763 			INP_WUNLOCK(inp);
1764 			error = sooptcopyout(sopt, &ti, sizeof ti);
1765 			break;
1766 		case TCP_CONGESTION:
1767 			bzero(buf, sizeof(buf));
1768 			strlcpy(buf, CC_ALGO(tp)->name, TCP_CA_NAME_MAX);
1769 			INP_WUNLOCK(inp);
1770 			error = sooptcopyout(sopt, buf, TCP_CA_NAME_MAX);
1771 			break;
1772 		case TCP_KEEPIDLE:
1773 		case TCP_KEEPINTVL:
1774 		case TCP_KEEPINIT:
1775 		case TCP_KEEPCNT:
1776 			switch (sopt->sopt_name) {
1777 			case TCP_KEEPIDLE:
1778 				ui = tp->t_keepidle / hz;
1779 				break;
1780 			case TCP_KEEPINTVL:
1781 				ui = tp->t_keepintvl / hz;
1782 				break;
1783 			case TCP_KEEPINIT:
1784 				ui = tp->t_keepinit / hz;
1785 				break;
1786 			case TCP_KEEPCNT:
1787 				ui = tp->t_keepcnt;
1788 				break;
1789 			}
1790 			INP_WUNLOCK(inp);
1791 			error = sooptcopyout(sopt, &ui, sizeof(ui));
1792 			break;
1793 #ifdef TCPPCAP
1794 		case TCP_PCAP_OUT:
1795 		case TCP_PCAP_IN:
1796 			optval = tcp_pcap_get_sock_max(TCP_PCAP_OUT ?
1797 					&(tp->t_outpkts) : &(tp->t_inpkts));
1798 			INP_WUNLOCK(inp);
1799 			error = sooptcopyout(sopt, &optval, sizeof optval);
1800 			break;
1801 #endif
1802 
1803 #ifdef TCP_RFC7413
1804 		case TCP_FASTOPEN:
1805 			optval = tp->t_flags & TF_FASTOPEN;
1806 			INP_WUNLOCK(inp);
1807 			error = sooptcopyout(sopt, &optval, sizeof optval);
1808 			break;
1809 #endif
1810 		default:
1811 			INP_WUNLOCK(inp);
1812 			error = ENOPROTOOPT;
1813 			break;
1814 		}
1815 		break;
1816 	}
1817 	return (error);
1818 }
1819 #undef INP_WLOCK_RECHECK
1820 
1821 /*
1822  * Attach TCP protocol to socket, allocating
1823  * internet protocol control block, tcp control block,
1824  * bufer space, and entering LISTEN state if to accept connections.
1825  */
1826 static int
1827 tcp_attach(struct socket *so)
1828 {
1829 	struct tcpcb *tp;
1830 	struct inpcb *inp;
1831 	int error;
1832 
1833 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
1834 		error = soreserve(so, V_tcp_sendspace, V_tcp_recvspace);
1835 		if (error)
1836 			return (error);
1837 	}
1838 	so->so_rcv.sb_flags |= SB_AUTOSIZE;
1839 	so->so_snd.sb_flags |= SB_AUTOSIZE;
1840 	INP_INFO_RLOCK(&V_tcbinfo);
1841 	error = in_pcballoc(so, &V_tcbinfo);
1842 	if (error) {
1843 		INP_INFO_RUNLOCK(&V_tcbinfo);
1844 		return (error);
1845 	}
1846 	inp = sotoinpcb(so);
1847 #ifdef INET6
1848 	if (inp->inp_vflag & INP_IPV6PROTO) {
1849 		inp->inp_vflag |= INP_IPV6;
1850 		inp->in6p_hops = -1;	/* use kernel default */
1851 	}
1852 	else
1853 #endif
1854 	inp->inp_vflag |= INP_IPV4;
1855 	tp = tcp_newtcpcb(inp);
1856 	if (tp == NULL) {
1857 		in_pcbdetach(inp);
1858 		in_pcbfree(inp);
1859 		INP_INFO_RUNLOCK(&V_tcbinfo);
1860 		return (ENOBUFS);
1861 	}
1862 	tp->t_state = TCPS_CLOSED;
1863 	INP_WUNLOCK(inp);
1864 	INP_INFO_RUNLOCK(&V_tcbinfo);
1865 	return (0);
1866 }
1867 
1868 /*
1869  * Initiate (or continue) disconnect.
1870  * If embryonic state, just send reset (once).
1871  * If in ``let data drain'' option and linger null, just drop.
1872  * Otherwise (hard), mark socket disconnecting and drop
1873  * current input data; switch states based on user close, and
1874  * send segment to peer (with FIN).
1875  */
1876 static void
1877 tcp_disconnect(struct tcpcb *tp)
1878 {
1879 	struct inpcb *inp = tp->t_inpcb;
1880 	struct socket *so = inp->inp_socket;
1881 
1882 	INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
1883 	INP_WLOCK_ASSERT(inp);
1884 
1885 	/*
1886 	 * Neither tcp_close() nor tcp_drop() should return NULL, as the
1887 	 * socket is still open.
1888 	 */
1889 	if (tp->t_state < TCPS_ESTABLISHED) {
1890 		tp = tcp_close(tp);
1891 		KASSERT(tp != NULL,
1892 		    ("tcp_disconnect: tcp_close() returned NULL"));
1893 	} else if ((so->so_options & SO_LINGER) && so->so_linger == 0) {
1894 		tp = tcp_drop(tp, 0);
1895 		KASSERT(tp != NULL,
1896 		    ("tcp_disconnect: tcp_drop() returned NULL"));
1897 	} else {
1898 		soisdisconnecting(so);
1899 		sbflush(&so->so_rcv);
1900 		tcp_usrclosed(tp);
1901 		if (!(inp->inp_flags & INP_DROPPED))
1902 			tp->t_fb->tfb_tcp_output(tp);
1903 	}
1904 }
1905 
1906 /*
1907  * User issued close, and wish to trail through shutdown states:
1908  * if never received SYN, just forget it.  If got a SYN from peer,
1909  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
1910  * If already got a FIN from peer, then almost done; go to LAST_ACK
1911  * state.  In all other cases, have already sent FIN to peer (e.g.
1912  * after PRU_SHUTDOWN), and just have to play tedious game waiting
1913  * for peer to send FIN or not respond to keep-alives, etc.
1914  * We can let the user exit from the close as soon as the FIN is acked.
1915  */
1916 static void
1917 tcp_usrclosed(struct tcpcb *tp)
1918 {
1919 
1920 	INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
1921 	INP_WLOCK_ASSERT(tp->t_inpcb);
1922 
1923 	switch (tp->t_state) {
1924 	case TCPS_LISTEN:
1925 #ifdef TCP_OFFLOAD
1926 		tcp_offload_listen_stop(tp);
1927 #endif
1928 		tcp_state_change(tp, TCPS_CLOSED);
1929 		/* FALLTHROUGH */
1930 	case TCPS_CLOSED:
1931 		tp = tcp_close(tp);
1932 		/*
1933 		 * tcp_close() should never return NULL here as the socket is
1934 		 * still open.
1935 		 */
1936 		KASSERT(tp != NULL,
1937 		    ("tcp_usrclosed: tcp_close() returned NULL"));
1938 		break;
1939 
1940 	case TCPS_SYN_SENT:
1941 	case TCPS_SYN_RECEIVED:
1942 		tp->t_flags |= TF_NEEDFIN;
1943 		break;
1944 
1945 	case TCPS_ESTABLISHED:
1946 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
1947 		break;
1948 
1949 	case TCPS_CLOSE_WAIT:
1950 		tcp_state_change(tp, TCPS_LAST_ACK);
1951 		break;
1952 	}
1953 	if (tp->t_state >= TCPS_FIN_WAIT_2) {
1954 		soisdisconnected(tp->t_inpcb->inp_socket);
1955 		/* Prevent the connection hanging in FIN_WAIT_2 forever. */
1956 		if (tp->t_state == TCPS_FIN_WAIT_2) {
1957 			int timeout;
1958 
1959 			timeout = (tcp_fast_finwait2_recycle) ?
1960 			    tcp_finwait2_timeout : TP_MAXIDLE(tp);
1961 			tcp_timer_activate(tp, TT_2MSL, timeout);
1962 		}
1963 	}
1964 }
1965 
1966 #ifdef DDB
1967 static void
1968 db_print_indent(int indent)
1969 {
1970 	int i;
1971 
1972 	for (i = 0; i < indent; i++)
1973 		db_printf(" ");
1974 }
1975 
1976 static void
1977 db_print_tstate(int t_state)
1978 {
1979 
1980 	switch (t_state) {
1981 	case TCPS_CLOSED:
1982 		db_printf("TCPS_CLOSED");
1983 		return;
1984 
1985 	case TCPS_LISTEN:
1986 		db_printf("TCPS_LISTEN");
1987 		return;
1988 
1989 	case TCPS_SYN_SENT:
1990 		db_printf("TCPS_SYN_SENT");
1991 		return;
1992 
1993 	case TCPS_SYN_RECEIVED:
1994 		db_printf("TCPS_SYN_RECEIVED");
1995 		return;
1996 
1997 	case TCPS_ESTABLISHED:
1998 		db_printf("TCPS_ESTABLISHED");
1999 		return;
2000 
2001 	case TCPS_CLOSE_WAIT:
2002 		db_printf("TCPS_CLOSE_WAIT");
2003 		return;
2004 
2005 	case TCPS_FIN_WAIT_1:
2006 		db_printf("TCPS_FIN_WAIT_1");
2007 		return;
2008 
2009 	case TCPS_CLOSING:
2010 		db_printf("TCPS_CLOSING");
2011 		return;
2012 
2013 	case TCPS_LAST_ACK:
2014 		db_printf("TCPS_LAST_ACK");
2015 		return;
2016 
2017 	case TCPS_FIN_WAIT_2:
2018 		db_printf("TCPS_FIN_WAIT_2");
2019 		return;
2020 
2021 	case TCPS_TIME_WAIT:
2022 		db_printf("TCPS_TIME_WAIT");
2023 		return;
2024 
2025 	default:
2026 		db_printf("unknown");
2027 		return;
2028 	}
2029 }
2030 
2031 static void
2032 db_print_tflags(u_int t_flags)
2033 {
2034 	int comma;
2035 
2036 	comma = 0;
2037 	if (t_flags & TF_ACKNOW) {
2038 		db_printf("%sTF_ACKNOW", comma ? ", " : "");
2039 		comma = 1;
2040 	}
2041 	if (t_flags & TF_DELACK) {
2042 		db_printf("%sTF_DELACK", comma ? ", " : "");
2043 		comma = 1;
2044 	}
2045 	if (t_flags & TF_NODELAY) {
2046 		db_printf("%sTF_NODELAY", comma ? ", " : "");
2047 		comma = 1;
2048 	}
2049 	if (t_flags & TF_NOOPT) {
2050 		db_printf("%sTF_NOOPT", comma ? ", " : "");
2051 		comma = 1;
2052 	}
2053 	if (t_flags & TF_SENTFIN) {
2054 		db_printf("%sTF_SENTFIN", comma ? ", " : "");
2055 		comma = 1;
2056 	}
2057 	if (t_flags & TF_REQ_SCALE) {
2058 		db_printf("%sTF_REQ_SCALE", comma ? ", " : "");
2059 		comma = 1;
2060 	}
2061 	if (t_flags & TF_RCVD_SCALE) {
2062 		db_printf("%sTF_RECVD_SCALE", comma ? ", " : "");
2063 		comma = 1;
2064 	}
2065 	if (t_flags & TF_REQ_TSTMP) {
2066 		db_printf("%sTF_REQ_TSTMP", comma ? ", " : "");
2067 		comma = 1;
2068 	}
2069 	if (t_flags & TF_RCVD_TSTMP) {
2070 		db_printf("%sTF_RCVD_TSTMP", comma ? ", " : "");
2071 		comma = 1;
2072 	}
2073 	if (t_flags & TF_SACK_PERMIT) {
2074 		db_printf("%sTF_SACK_PERMIT", comma ? ", " : "");
2075 		comma = 1;
2076 	}
2077 	if (t_flags & TF_NEEDSYN) {
2078 		db_printf("%sTF_NEEDSYN", comma ? ", " : "");
2079 		comma = 1;
2080 	}
2081 	if (t_flags & TF_NEEDFIN) {
2082 		db_printf("%sTF_NEEDFIN", comma ? ", " : "");
2083 		comma = 1;
2084 	}
2085 	if (t_flags & TF_NOPUSH) {
2086 		db_printf("%sTF_NOPUSH", comma ? ", " : "");
2087 		comma = 1;
2088 	}
2089 	if (t_flags & TF_MORETOCOME) {
2090 		db_printf("%sTF_MORETOCOME", comma ? ", " : "");
2091 		comma = 1;
2092 	}
2093 	if (t_flags & TF_LQ_OVERFLOW) {
2094 		db_printf("%sTF_LQ_OVERFLOW", comma ? ", " : "");
2095 		comma = 1;
2096 	}
2097 	if (t_flags & TF_LASTIDLE) {
2098 		db_printf("%sTF_LASTIDLE", comma ? ", " : "");
2099 		comma = 1;
2100 	}
2101 	if (t_flags & TF_RXWIN0SENT) {
2102 		db_printf("%sTF_RXWIN0SENT", comma ? ", " : "");
2103 		comma = 1;
2104 	}
2105 	if (t_flags & TF_FASTRECOVERY) {
2106 		db_printf("%sTF_FASTRECOVERY", comma ? ", " : "");
2107 		comma = 1;
2108 	}
2109 	if (t_flags & TF_CONGRECOVERY) {
2110 		db_printf("%sTF_CONGRECOVERY", comma ? ", " : "");
2111 		comma = 1;
2112 	}
2113 	if (t_flags & TF_WASFRECOVERY) {
2114 		db_printf("%sTF_WASFRECOVERY", comma ? ", " : "");
2115 		comma = 1;
2116 	}
2117 	if (t_flags & TF_SIGNATURE) {
2118 		db_printf("%sTF_SIGNATURE", comma ? ", " : "");
2119 		comma = 1;
2120 	}
2121 	if (t_flags & TF_FORCEDATA) {
2122 		db_printf("%sTF_FORCEDATA", comma ? ", " : "");
2123 		comma = 1;
2124 	}
2125 	if (t_flags & TF_TSO) {
2126 		db_printf("%sTF_TSO", comma ? ", " : "");
2127 		comma = 1;
2128 	}
2129 	if (t_flags & TF_ECN_PERMIT) {
2130 		db_printf("%sTF_ECN_PERMIT", comma ? ", " : "");
2131 		comma = 1;
2132 	}
2133 	if (t_flags & TF_FASTOPEN) {
2134 		db_printf("%sTF_FASTOPEN", comma ? ", " : "");
2135 		comma = 1;
2136 	}
2137 }
2138 
2139 static void
2140 db_print_toobflags(char t_oobflags)
2141 {
2142 	int comma;
2143 
2144 	comma = 0;
2145 	if (t_oobflags & TCPOOB_HAVEDATA) {
2146 		db_printf("%sTCPOOB_HAVEDATA", comma ? ", " : "");
2147 		comma = 1;
2148 	}
2149 	if (t_oobflags & TCPOOB_HADDATA) {
2150 		db_printf("%sTCPOOB_HADDATA", comma ? ", " : "");
2151 		comma = 1;
2152 	}
2153 }
2154 
2155 static void
2156 db_print_tcpcb(struct tcpcb *tp, const char *name, int indent)
2157 {
2158 
2159 	db_print_indent(indent);
2160 	db_printf("%s at %p\n", name, tp);
2161 
2162 	indent += 2;
2163 
2164 	db_print_indent(indent);
2165 	db_printf("t_segq first: %p   t_segqlen: %d   t_dupacks: %d\n",
2166 	   LIST_FIRST(&tp->t_segq), tp->t_segqlen, tp->t_dupacks);
2167 
2168 	db_print_indent(indent);
2169 	db_printf("tt_rexmt: %p   tt_persist: %p   tt_keep: %p\n",
2170 	    &tp->t_timers->tt_rexmt, &tp->t_timers->tt_persist, &tp->t_timers->tt_keep);
2171 
2172 	db_print_indent(indent);
2173 	db_printf("tt_2msl: %p   tt_delack: %p   t_inpcb: %p\n", &tp->t_timers->tt_2msl,
2174 	    &tp->t_timers->tt_delack, tp->t_inpcb);
2175 
2176 	db_print_indent(indent);
2177 	db_printf("t_state: %d (", tp->t_state);
2178 	db_print_tstate(tp->t_state);
2179 	db_printf(")\n");
2180 
2181 	db_print_indent(indent);
2182 	db_printf("t_flags: 0x%x (", tp->t_flags);
2183 	db_print_tflags(tp->t_flags);
2184 	db_printf(")\n");
2185 
2186 	db_print_indent(indent);
2187 	db_printf("snd_una: 0x%08x   snd_max: 0x%08x   snd_nxt: x0%08x\n",
2188 	    tp->snd_una, tp->snd_max, tp->snd_nxt);
2189 
2190 	db_print_indent(indent);
2191 	db_printf("snd_up: 0x%08x   snd_wl1: 0x%08x   snd_wl2: 0x%08x\n",
2192 	   tp->snd_up, tp->snd_wl1, tp->snd_wl2);
2193 
2194 	db_print_indent(indent);
2195 	db_printf("iss: 0x%08x   irs: 0x%08x   rcv_nxt: 0x%08x\n",
2196 	    tp->iss, tp->irs, tp->rcv_nxt);
2197 
2198 	db_print_indent(indent);
2199 	db_printf("rcv_adv: 0x%08x   rcv_wnd: %lu   rcv_up: 0x%08x\n",
2200 	    tp->rcv_adv, tp->rcv_wnd, tp->rcv_up);
2201 
2202 	db_print_indent(indent);
2203 	db_printf("snd_wnd: %lu   snd_cwnd: %lu\n",
2204 	   tp->snd_wnd, tp->snd_cwnd);
2205 
2206 	db_print_indent(indent);
2207 	db_printf("snd_ssthresh: %lu   snd_recover: "
2208 	    "0x%08x\n", tp->snd_ssthresh, tp->snd_recover);
2209 
2210 	db_print_indent(indent);
2211 	db_printf("t_maxopd: %u   t_rcvtime: %u   t_startime: %u\n",
2212 	    tp->t_maxopd, tp->t_rcvtime, tp->t_starttime);
2213 
2214 	db_print_indent(indent);
2215 	db_printf("t_rttime: %u   t_rtsq: 0x%08x\n",
2216 	    tp->t_rtttime, tp->t_rtseq);
2217 
2218 	db_print_indent(indent);
2219 	db_printf("t_rxtcur: %d   t_maxseg: %u   t_srtt: %d\n",
2220 	    tp->t_rxtcur, tp->t_maxseg, tp->t_srtt);
2221 
2222 	db_print_indent(indent);
2223 	db_printf("t_rttvar: %d   t_rxtshift: %d   t_rttmin: %u   "
2224 	    "t_rttbest: %u\n", tp->t_rttvar, tp->t_rxtshift, tp->t_rttmin,
2225 	    tp->t_rttbest);
2226 
2227 	db_print_indent(indent);
2228 	db_printf("t_rttupdated: %lu   max_sndwnd: %lu   t_softerror: %d\n",
2229 	    tp->t_rttupdated, tp->max_sndwnd, tp->t_softerror);
2230 
2231 	db_print_indent(indent);
2232 	db_printf("t_oobflags: 0x%x (", tp->t_oobflags);
2233 	db_print_toobflags(tp->t_oobflags);
2234 	db_printf(")   t_iobc: 0x%02x\n", tp->t_iobc);
2235 
2236 	db_print_indent(indent);
2237 	db_printf("snd_scale: %u   rcv_scale: %u   request_r_scale: %u\n",
2238 	    tp->snd_scale, tp->rcv_scale, tp->request_r_scale);
2239 
2240 	db_print_indent(indent);
2241 	db_printf("ts_recent: %u   ts_recent_age: %u\n",
2242 	    tp->ts_recent, tp->ts_recent_age);
2243 
2244 	db_print_indent(indent);
2245 	db_printf("ts_offset: %u   last_ack_sent: 0x%08x   snd_cwnd_prev: "
2246 	    "%lu\n", tp->ts_offset, tp->last_ack_sent, tp->snd_cwnd_prev);
2247 
2248 	db_print_indent(indent);
2249 	db_printf("snd_ssthresh_prev: %lu   snd_recover_prev: 0x%08x   "
2250 	    "t_badrxtwin: %u\n", tp->snd_ssthresh_prev,
2251 	    tp->snd_recover_prev, tp->t_badrxtwin);
2252 
2253 	db_print_indent(indent);
2254 	db_printf("snd_numholes: %d  snd_holes first: %p\n",
2255 	    tp->snd_numholes, TAILQ_FIRST(&tp->snd_holes));
2256 
2257 	db_print_indent(indent);
2258 	db_printf("snd_fack: 0x%08x   rcv_numsacks: %d   sack_newdata: "
2259 	    "0x%08x\n", tp->snd_fack, tp->rcv_numsacks, tp->sack_newdata);
2260 
2261 	/* Skip sackblks, sackhint. */
2262 
2263 	db_print_indent(indent);
2264 	db_printf("t_rttlow: %d   rfbuf_ts: %u   rfbuf_cnt: %d\n",
2265 	    tp->t_rttlow, tp->rfbuf_ts, tp->rfbuf_cnt);
2266 }
2267 
2268 DB_SHOW_COMMAND(tcpcb, db_show_tcpcb)
2269 {
2270 	struct tcpcb *tp;
2271 
2272 	if (!have_addr) {
2273 		db_printf("usage: show tcpcb <addr>\n");
2274 		return;
2275 	}
2276 	tp = (struct tcpcb *)addr;
2277 
2278 	db_print_tcpcb(tp, "tcpcb", 0);
2279 }
2280 #endif
2281