xref: /freebsd/sys/netinet/tcp_usrreq.c (revision 38069501)
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  * 3. 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_ipsec.h"
45 #include "opt_tcpdebug.h"
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/limits.h>
50 #include <sys/malloc.h>
51 #include <sys/refcount.h>
52 #include <sys/kernel.h>
53 #include <sys/sysctl.h>
54 #include <sys/mbuf.h>
55 #ifdef INET6
56 #include <sys/domain.h>
57 #endif /* INET6 */
58 #include <sys/socket.h>
59 #include <sys/socketvar.h>
60 #include <sys/protosw.h>
61 #include <sys/proc.h>
62 #include <sys/jail.h>
63 #include <sys/syslog.h>
64 
65 #ifdef DDB
66 #include <ddb/ddb.h>
67 #endif
68 
69 #include <net/if.h>
70 #include <net/if_var.h>
71 #include <net/route.h>
72 #include <net/vnet.h>
73 
74 #include <netinet/in.h>
75 #include <netinet/in_kdtrace.h>
76 #include <netinet/in_pcb.h>
77 #include <netinet/in_systm.h>
78 #include <netinet/in_var.h>
79 #include <netinet/ip_var.h>
80 #ifdef INET6
81 #include <netinet/ip6.h>
82 #include <netinet6/in6_pcb.h>
83 #include <netinet6/ip6_var.h>
84 #include <netinet6/scope6_var.h>
85 #endif
86 #ifdef TCP_RFC7413
87 #include <netinet/tcp_fastopen.h>
88 #endif
89 #include <netinet/tcp.h>
90 #include <netinet/tcp_fsm.h>
91 #include <netinet/tcp_seq.h>
92 #include <netinet/tcp_timer.h>
93 #include <netinet/tcp_var.h>
94 #include <netinet/tcpip.h>
95 #include <netinet/cc/cc.h>
96 #ifdef TCPPCAP
97 #include <netinet/tcp_pcap.h>
98 #endif
99 #ifdef TCPDEBUG
100 #include <netinet/tcp_debug.h>
101 #endif
102 #ifdef TCP_OFFLOAD
103 #include <netinet/tcp_offload.h>
104 #endif
105 #include <netipsec/ipsec_support.h>
106 
107 /*
108  * TCP protocol interface to socket abstraction.
109  */
110 static int	tcp_attach(struct socket *);
111 #ifdef INET
112 static int	tcp_connect(struct tcpcb *, struct sockaddr *,
113 		    struct thread *td);
114 #endif /* INET */
115 #ifdef INET6
116 static int	tcp6_connect(struct tcpcb *, struct sockaddr *,
117 		    struct thread *td);
118 #endif /* INET6 */
119 static void	tcp_disconnect(struct tcpcb *);
120 static void	tcp_usrclosed(struct tcpcb *);
121 static void	tcp_fill_info(struct tcpcb *, struct tcp_info *);
122 
123 #ifdef TCPDEBUG
124 #define	TCPDEBUG0	int ostate = 0
125 #define	TCPDEBUG1()	ostate = tp ? tp->t_state : 0
126 #define	TCPDEBUG2(req)	if (tp && (so->so_options & SO_DEBUG)) \
127 				tcp_trace(TA_USER, ostate, tp, 0, 0, req)
128 #else
129 #define	TCPDEBUG0
130 #define	TCPDEBUG1()
131 #define	TCPDEBUG2(req)
132 #endif
133 
134 /*
135  * TCP attaches to socket via pru_attach(), reserving space,
136  * and an internet control block.
137  */
138 static int
139 tcp_usr_attach(struct socket *so, int proto, struct thread *td)
140 {
141 	struct inpcb *inp;
142 	struct tcpcb *tp = NULL;
143 	int error;
144 	TCPDEBUG0;
145 
146 	inp = sotoinpcb(so);
147 	KASSERT(inp == NULL, ("tcp_usr_attach: inp != NULL"));
148 	TCPDEBUG1();
149 
150 	error = tcp_attach(so);
151 	if (error)
152 		goto out;
153 
154 	if ((so->so_options & SO_LINGER) && so->so_linger == 0)
155 		so->so_linger = TCP_LINGERTIME;
156 
157 	inp = sotoinpcb(so);
158 	tp = intotcpcb(inp);
159 out:
160 	TCPDEBUG2(PRU_ATTACH);
161 	TCP_PROBE2(debug__user, tp, PRU_ATTACH);
162 	return error;
163 }
164 
165 /*
166  * tcp_detach is called when the socket layer loses its final reference
167  * to the socket, be it a file descriptor reference, a reference from TCP,
168  * etc.  At this point, there is only one case in which we will keep around
169  * inpcb state: time wait.
170  *
171  * This function can probably be re-absorbed back into tcp_usr_detach() now
172  * that there is a single detach path.
173  */
174 static void
175 tcp_detach(struct socket *so, struct inpcb *inp)
176 {
177 	struct tcpcb *tp;
178 
179 	INP_INFO_LOCK_ASSERT(&V_tcbinfo);
180 	INP_WLOCK_ASSERT(inp);
181 
182 	KASSERT(so->so_pcb == inp, ("tcp_detach: so_pcb != inp"));
183 	KASSERT(inp->inp_socket == so, ("tcp_detach: inp_socket != so"));
184 
185 	tp = intotcpcb(inp);
186 
187 	if (inp->inp_flags & INP_TIMEWAIT) {
188 		/*
189 		 * There are two cases to handle: one in which the time wait
190 		 * state is being discarded (INP_DROPPED), and one in which
191 		 * this connection will remain in timewait.  In the former,
192 		 * it is time to discard all state (except tcptw, which has
193 		 * already been discarded by the timewait close code, which
194 		 * should be further up the call stack somewhere).  In the
195 		 * latter case, we detach from the socket, but leave the pcb
196 		 * present until timewait ends.
197 		 *
198 		 * XXXRW: Would it be cleaner to free the tcptw here?
199 		 *
200 		 * Astute question indeed, from twtcp perspective there are
201 		 * three cases to consider:
202 		 *
203 		 * #1 tcp_detach is called at tcptw creation time by
204 		 *  tcp_twstart, then do not discard the newly created tcptw
205 		 *  and leave inpcb present until timewait ends
206 		 * #2 tcp_detach is called at timewait end (or reuse) by
207 		 *  tcp_twclose, then the tcptw has already been discarded
208 		 *  (or reused) and inpcb is freed here
209 		 * #3 tcp_detach is called() after timewait ends (or reuse)
210 		 *  (e.g. by soclose), then tcptw has already been discarded
211 		 *  (or reused) and inpcb is freed here
212 		 *
213 		 *  In all three cases the tcptw should not be freed here.
214 		 */
215 		if (inp->inp_flags & INP_DROPPED) {
216 			in_pcbdetach(inp);
217 			if (__predict_true(tp == NULL)) {
218 				in_pcbfree(inp);
219 			} else {
220 				/*
221 				 * This case should not happen as in TIMEWAIT
222 				 * state the inp should not be destroyed before
223 				 * its tcptw.  If INVARIANTS is defined, panic.
224 				 */
225 #ifdef INVARIANTS
226 				panic("%s: Panic before an inp double-free: "
227 				    "INP_TIMEWAIT && INP_DROPPED && tp != NULL"
228 				    , __func__);
229 #else
230 				log(LOG_ERR, "%s: Avoid an inp double-free: "
231 				    "INP_TIMEWAIT && INP_DROPPED && tp != NULL"
232 				    , __func__);
233 #endif
234 				INP_WUNLOCK(inp);
235 			}
236 		} else {
237 			in_pcbdetach(inp);
238 			INP_WUNLOCK(inp);
239 		}
240 	} else {
241 		/*
242 		 * If the connection is not in timewait, we consider two
243 		 * two conditions: one in which no further processing is
244 		 * necessary (dropped || embryonic), and one in which TCP is
245 		 * not yet done, but no longer requires the socket, so the
246 		 * pcb will persist for the time being.
247 		 *
248 		 * XXXRW: Does the second case still occur?
249 		 */
250 		if (inp->inp_flags & INP_DROPPED ||
251 		    tp->t_state < TCPS_SYN_SENT) {
252 			tcp_discardcb(tp);
253 			in_pcbdetach(inp);
254 			in_pcbfree(inp);
255 		} else {
256 			in_pcbdetach(inp);
257 			INP_WUNLOCK(inp);
258 		}
259 	}
260 }
261 
262 /*
263  * pru_detach() detaches the TCP protocol from the socket.
264  * If the protocol state is non-embryonic, then can't
265  * do this directly: have to initiate a pru_disconnect(),
266  * which may finish later; embryonic TCB's can just
267  * be discarded here.
268  */
269 static void
270 tcp_usr_detach(struct socket *so)
271 {
272 	struct inpcb *inp;
273 	int rlock = 0;
274 
275 	inp = sotoinpcb(so);
276 	KASSERT(inp != NULL, ("tcp_usr_detach: inp == NULL"));
277 	if (!INP_INFO_WLOCKED(&V_tcbinfo)) {
278 		INP_INFO_RLOCK(&V_tcbinfo);
279 		rlock = 1;
280 	}
281 	INP_WLOCK(inp);
282 	KASSERT(inp->inp_socket != NULL,
283 	    ("tcp_usr_detach: inp_socket == NULL"));
284 	tcp_detach(so, inp);
285 	if (rlock)
286 		INP_INFO_RUNLOCK(&V_tcbinfo);
287 }
288 
289 #ifdef INET
290 /*
291  * Give the socket an address.
292  */
293 static int
294 tcp_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
295 {
296 	int error = 0;
297 	struct inpcb *inp;
298 	struct tcpcb *tp = NULL;
299 	struct sockaddr_in *sinp;
300 
301 	sinp = (struct sockaddr_in *)nam;
302 	if (nam->sa_len != sizeof (*sinp))
303 		return (EINVAL);
304 	/*
305 	 * Must check for multicast addresses and disallow binding
306 	 * to them.
307 	 */
308 	if (sinp->sin_family == AF_INET &&
309 	    IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
310 		return (EAFNOSUPPORT);
311 
312 	TCPDEBUG0;
313 	inp = sotoinpcb(so);
314 	KASSERT(inp != NULL, ("tcp_usr_bind: inp == NULL"));
315 	INP_WLOCK(inp);
316 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
317 		error = EINVAL;
318 		goto out;
319 	}
320 	tp = intotcpcb(inp);
321 	TCPDEBUG1();
322 	INP_HASH_WLOCK(&V_tcbinfo);
323 	error = in_pcbbind(inp, nam, td->td_ucred);
324 	INP_HASH_WUNLOCK(&V_tcbinfo);
325 out:
326 	TCPDEBUG2(PRU_BIND);
327 	TCP_PROBE2(debug__user, tp, PRU_BIND);
328 	INP_WUNLOCK(inp);
329 
330 	return (error);
331 }
332 #endif /* INET */
333 
334 #ifdef INET6
335 static int
336 tcp6_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
337 {
338 	int error = 0;
339 	struct inpcb *inp;
340 	struct tcpcb *tp = NULL;
341 	struct sockaddr_in6 *sin6p;
342 
343 	sin6p = (struct sockaddr_in6 *)nam;
344 	if (nam->sa_len != sizeof (*sin6p))
345 		return (EINVAL);
346 	/*
347 	 * Must check for multicast addresses and disallow binding
348 	 * to them.
349 	 */
350 	if (sin6p->sin6_family == AF_INET6 &&
351 	    IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
352 		return (EAFNOSUPPORT);
353 
354 	TCPDEBUG0;
355 	inp = sotoinpcb(so);
356 	KASSERT(inp != NULL, ("tcp6_usr_bind: inp == NULL"));
357 	INP_WLOCK(inp);
358 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
359 		error = EINVAL;
360 		goto out;
361 	}
362 	tp = intotcpcb(inp);
363 	TCPDEBUG1();
364 	INP_HASH_WLOCK(&V_tcbinfo);
365 	inp->inp_vflag &= ~INP_IPV4;
366 	inp->inp_vflag |= INP_IPV6;
367 #ifdef INET
368 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
369 		if (IN6_IS_ADDR_UNSPECIFIED(&sin6p->sin6_addr))
370 			inp->inp_vflag |= INP_IPV4;
371 		else if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
372 			struct sockaddr_in sin;
373 
374 			in6_sin6_2_sin(&sin, sin6p);
375 			inp->inp_vflag |= INP_IPV4;
376 			inp->inp_vflag &= ~INP_IPV6;
377 			error = in_pcbbind(inp, (struct sockaddr *)&sin,
378 			    td->td_ucred);
379 			INP_HASH_WUNLOCK(&V_tcbinfo);
380 			goto out;
381 		}
382 	}
383 #endif
384 	error = in6_pcbbind(inp, nam, td->td_ucred);
385 	INP_HASH_WUNLOCK(&V_tcbinfo);
386 out:
387 	TCPDEBUG2(PRU_BIND);
388 	TCP_PROBE2(debug__user, tp, PRU_BIND);
389 	INP_WUNLOCK(inp);
390 	return (error);
391 }
392 #endif /* INET6 */
393 
394 #ifdef INET
395 /*
396  * Prepare to accept connections.
397  */
398 static int
399 tcp_usr_listen(struct socket *so, int backlog, struct thread *td)
400 {
401 	int error = 0;
402 	struct inpcb *inp;
403 	struct tcpcb *tp = NULL;
404 
405 	TCPDEBUG0;
406 	inp = sotoinpcb(so);
407 	KASSERT(inp != NULL, ("tcp_usr_listen: inp == NULL"));
408 	INP_WLOCK(inp);
409 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
410 		error = EINVAL;
411 		goto out;
412 	}
413 	tp = intotcpcb(inp);
414 	TCPDEBUG1();
415 	SOCK_LOCK(so);
416 	error = solisten_proto_check(so);
417 	INP_HASH_WLOCK(&V_tcbinfo);
418 	if (error == 0 && inp->inp_lport == 0)
419 		error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
420 	INP_HASH_WUNLOCK(&V_tcbinfo);
421 	if (error == 0) {
422 		tcp_state_change(tp, TCPS_LISTEN);
423 		solisten_proto(so, backlog);
424 #ifdef TCP_OFFLOAD
425 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
426 			tcp_offload_listen_start(tp);
427 #endif
428 	}
429 	SOCK_UNLOCK(so);
430 
431 #ifdef TCP_RFC7413
432 	if (IS_FASTOPEN(tp->t_flags))
433 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
434 #endif
435 out:
436 	TCPDEBUG2(PRU_LISTEN);
437 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
438 	INP_WUNLOCK(inp);
439 	return (error);
440 }
441 #endif /* INET */
442 
443 #ifdef INET6
444 static int
445 tcp6_usr_listen(struct socket *so, int backlog, struct thread *td)
446 {
447 	int error = 0;
448 	struct inpcb *inp;
449 	struct tcpcb *tp = NULL;
450 
451 	TCPDEBUG0;
452 	inp = sotoinpcb(so);
453 	KASSERT(inp != NULL, ("tcp6_usr_listen: inp == NULL"));
454 	INP_WLOCK(inp);
455 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
456 		error = EINVAL;
457 		goto out;
458 	}
459 	tp = intotcpcb(inp);
460 	TCPDEBUG1();
461 	SOCK_LOCK(so);
462 	error = solisten_proto_check(so);
463 	INP_HASH_WLOCK(&V_tcbinfo);
464 	if (error == 0 && inp->inp_lport == 0) {
465 		inp->inp_vflag &= ~INP_IPV4;
466 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
467 			inp->inp_vflag |= INP_IPV4;
468 		error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
469 	}
470 	INP_HASH_WUNLOCK(&V_tcbinfo);
471 	if (error == 0) {
472 		tcp_state_change(tp, TCPS_LISTEN);
473 		solisten_proto(so, backlog);
474 #ifdef TCP_OFFLOAD
475 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
476 			tcp_offload_listen_start(tp);
477 #endif
478 	}
479 	SOCK_UNLOCK(so);
480 
481 #ifdef TCP_RFC7413
482 	if (IS_FASTOPEN(tp->t_flags))
483 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
484 #endif
485 out:
486 	TCPDEBUG2(PRU_LISTEN);
487 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
488 	INP_WUNLOCK(inp);
489 	return (error);
490 }
491 #endif /* INET6 */
492 
493 #ifdef INET
494 /*
495  * Initiate connection to peer.
496  * Create a template for use in transmissions on this connection.
497  * Enter SYN_SENT state, and mark socket as connecting.
498  * Start keep-alive timer, and seed output sequence space.
499  * Send initial segment on connection.
500  */
501 static int
502 tcp_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
503 {
504 	int error = 0;
505 	struct inpcb *inp;
506 	struct tcpcb *tp = NULL;
507 	struct sockaddr_in *sinp;
508 
509 	sinp = (struct sockaddr_in *)nam;
510 	if (nam->sa_len != sizeof (*sinp))
511 		return (EINVAL);
512 	/*
513 	 * Must disallow TCP ``connections'' to multicast addresses.
514 	 */
515 	if (sinp->sin_family == AF_INET
516 	    && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
517 		return (EAFNOSUPPORT);
518 	if ((error = prison_remote_ip4(td->td_ucred, &sinp->sin_addr)) != 0)
519 		return (error);
520 
521 	TCPDEBUG0;
522 	inp = sotoinpcb(so);
523 	KASSERT(inp != NULL, ("tcp_usr_connect: inp == NULL"));
524 	INP_WLOCK(inp);
525 	if (inp->inp_flags & INP_TIMEWAIT) {
526 		error = EADDRINUSE;
527 		goto out;
528 	}
529 	if (inp->inp_flags & INP_DROPPED) {
530 		error = ECONNREFUSED;
531 		goto out;
532 	}
533 	tp = intotcpcb(inp);
534 	TCPDEBUG1();
535 	if ((error = tcp_connect(tp, nam, td)) != 0)
536 		goto out;
537 #ifdef TCP_OFFLOAD
538 	if (registered_toedevs > 0 &&
539 	    (so->so_options & SO_NO_OFFLOAD) == 0 &&
540 	    (error = tcp_offload_connect(so, nam)) == 0)
541 		goto out;
542 #endif
543 	tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
544 	error = tp->t_fb->tfb_tcp_output(tp);
545 out:
546 	TCPDEBUG2(PRU_CONNECT);
547 	TCP_PROBE2(debug__user, tp, PRU_CONNECT);
548 	INP_WUNLOCK(inp);
549 	return (error);
550 }
551 #endif /* INET */
552 
553 #ifdef INET6
554 static int
555 tcp6_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
556 {
557 	int error = 0;
558 	struct inpcb *inp;
559 	struct tcpcb *tp = NULL;
560 	struct sockaddr_in6 *sin6p;
561 
562 	TCPDEBUG0;
563 
564 	sin6p = (struct sockaddr_in6 *)nam;
565 	if (nam->sa_len != sizeof (*sin6p))
566 		return (EINVAL);
567 	/*
568 	 * Must disallow TCP ``connections'' to multicast addresses.
569 	 */
570 	if (sin6p->sin6_family == AF_INET6
571 	    && IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
572 		return (EAFNOSUPPORT);
573 
574 	inp = sotoinpcb(so);
575 	KASSERT(inp != NULL, ("tcp6_usr_connect: inp == NULL"));
576 	INP_WLOCK(inp);
577 	if (inp->inp_flags & INP_TIMEWAIT) {
578 		error = EADDRINUSE;
579 		goto out;
580 	}
581 	if (inp->inp_flags & INP_DROPPED) {
582 		error = ECONNREFUSED;
583 		goto out;
584 	}
585 	tp = intotcpcb(inp);
586 	TCPDEBUG1();
587 #ifdef INET
588 	/*
589 	 * XXXRW: Some confusion: V4/V6 flags relate to binding, and
590 	 * therefore probably require the hash lock, which isn't held here.
591 	 * Is this a significant problem?
592 	 */
593 	if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
594 		struct sockaddr_in sin;
595 
596 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
597 			error = EINVAL;
598 			goto out;
599 		}
600 		if ((inp->inp_vflag & INP_IPV4) == 0) {
601 			error = EAFNOSUPPORT;
602 			goto out;
603 		}
604 
605 		in6_sin6_2_sin(&sin, sin6p);
606 		inp->inp_vflag |= INP_IPV4;
607 		inp->inp_vflag &= ~INP_IPV6;
608 		if ((error = prison_remote_ip4(td->td_ucred,
609 		    &sin.sin_addr)) != 0)
610 			goto out;
611 		if ((error = tcp_connect(tp, (struct sockaddr *)&sin, td)) != 0)
612 			goto out;
613 #ifdef TCP_OFFLOAD
614 		if (registered_toedevs > 0 &&
615 		    (so->so_options & SO_NO_OFFLOAD) == 0 &&
616 		    (error = tcp_offload_connect(so, nam)) == 0)
617 			goto out;
618 #endif
619 		error = tp->t_fb->tfb_tcp_output(tp);
620 		goto out;
621 	} else {
622 		if ((inp->inp_vflag & INP_IPV6) == 0) {
623 			error = EAFNOSUPPORT;
624 			goto out;
625 		}
626 	}
627 #endif
628 	inp->inp_vflag &= ~INP_IPV4;
629 	inp->inp_vflag |= INP_IPV6;
630 	inp->inp_inc.inc_flags |= INC_ISIPV6;
631 	if ((error = prison_remote_ip6(td->td_ucred, &sin6p->sin6_addr)) != 0)
632 		goto out;
633 	if ((error = tcp6_connect(tp, nam, td)) != 0)
634 		goto out;
635 #ifdef TCP_OFFLOAD
636 	if (registered_toedevs > 0 &&
637 	    (so->so_options & SO_NO_OFFLOAD) == 0 &&
638 	    (error = tcp_offload_connect(so, nam)) == 0)
639 		goto out;
640 #endif
641 	tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
642 	error = tp->t_fb->tfb_tcp_output(tp);
643 
644 out:
645 	TCPDEBUG2(PRU_CONNECT);
646 	TCP_PROBE2(debug__user, tp, PRU_CONNECT);
647 	INP_WUNLOCK(inp);
648 	return (error);
649 }
650 #endif /* INET6 */
651 
652 /*
653  * Initiate disconnect from peer.
654  * If connection never passed embryonic stage, just drop;
655  * else if don't need to let data drain, then can just drop anyways,
656  * else have to begin TCP shutdown process: mark socket disconnecting,
657  * drain unread data, state switch to reflect user close, and
658  * send segment (e.g. FIN) to peer.  Socket will be really disconnected
659  * when peer sends FIN and acks ours.
660  *
661  * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
662  */
663 static int
664 tcp_usr_disconnect(struct socket *so)
665 {
666 	struct inpcb *inp;
667 	struct tcpcb *tp = NULL;
668 	int error = 0;
669 
670 	TCPDEBUG0;
671 	INP_INFO_RLOCK(&V_tcbinfo);
672 	inp = sotoinpcb(so);
673 	KASSERT(inp != NULL, ("tcp_usr_disconnect: inp == NULL"));
674 	INP_WLOCK(inp);
675 	if (inp->inp_flags & INP_TIMEWAIT)
676 		goto out;
677 	if (inp->inp_flags & INP_DROPPED) {
678 		error = ECONNRESET;
679 		goto out;
680 	}
681 	tp = intotcpcb(inp);
682 	TCPDEBUG1();
683 	tcp_disconnect(tp);
684 out:
685 	TCPDEBUG2(PRU_DISCONNECT);
686 	TCP_PROBE2(debug__user, tp, PRU_DISCONNECT);
687 	INP_WUNLOCK(inp);
688 	INP_INFO_RUNLOCK(&V_tcbinfo);
689 	return (error);
690 }
691 
692 #ifdef INET
693 /*
694  * Accept a connection.  Essentially all the work is done at higher levels;
695  * just return the address of the peer, storing through addr.
696  */
697 static int
698 tcp_usr_accept(struct socket *so, struct sockaddr **nam)
699 {
700 	int error = 0;
701 	struct inpcb *inp = NULL;
702 	struct tcpcb *tp = NULL;
703 	struct in_addr addr;
704 	in_port_t port = 0;
705 	TCPDEBUG0;
706 
707 	if (so->so_state & SS_ISDISCONNECTED)
708 		return (ECONNABORTED);
709 
710 	inp = sotoinpcb(so);
711 	KASSERT(inp != NULL, ("tcp_usr_accept: inp == NULL"));
712 	INP_WLOCK(inp);
713 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
714 		error = ECONNABORTED;
715 		goto out;
716 	}
717 	tp = intotcpcb(inp);
718 	TCPDEBUG1();
719 
720 	/*
721 	 * We inline in_getpeeraddr and COMMON_END here, so that we can
722 	 * copy the data of interest and defer the malloc until after we
723 	 * release the lock.
724 	 */
725 	port = inp->inp_fport;
726 	addr = inp->inp_faddr;
727 
728 out:
729 	TCPDEBUG2(PRU_ACCEPT);
730 	TCP_PROBE2(debug__user, tp, PRU_ACCEPT);
731 	INP_WUNLOCK(inp);
732 	if (error == 0)
733 		*nam = in_sockaddr(port, &addr);
734 	return error;
735 }
736 #endif /* INET */
737 
738 #ifdef INET6
739 static int
740 tcp6_usr_accept(struct socket *so, struct sockaddr **nam)
741 {
742 	struct inpcb *inp = NULL;
743 	int error = 0;
744 	struct tcpcb *tp = NULL;
745 	struct in_addr addr;
746 	struct in6_addr addr6;
747 	in_port_t port = 0;
748 	int v4 = 0;
749 	TCPDEBUG0;
750 
751 	if (so->so_state & SS_ISDISCONNECTED)
752 		return (ECONNABORTED);
753 
754 	inp = sotoinpcb(so);
755 	KASSERT(inp != NULL, ("tcp6_usr_accept: inp == NULL"));
756 	INP_INFO_RLOCK(&V_tcbinfo);
757 	INP_WLOCK(inp);
758 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
759 		error = ECONNABORTED;
760 		goto out;
761 	}
762 	tp = intotcpcb(inp);
763 	TCPDEBUG1();
764 
765 	/*
766 	 * We inline in6_mapped_peeraddr and COMMON_END here, so that we can
767 	 * copy the data of interest and defer the malloc until after we
768 	 * release the lock.
769 	 */
770 	if (inp->inp_vflag & INP_IPV4) {
771 		v4 = 1;
772 		port = inp->inp_fport;
773 		addr = inp->inp_faddr;
774 	} else {
775 		port = inp->inp_fport;
776 		addr6 = inp->in6p_faddr;
777 	}
778 
779 out:
780 	TCPDEBUG2(PRU_ACCEPT);
781 	TCP_PROBE2(debug__user, tp, PRU_ACCEPT);
782 	INP_WUNLOCK(inp);
783 	INP_INFO_RUNLOCK(&V_tcbinfo);
784 	if (error == 0) {
785 		if (v4)
786 			*nam = in6_v4mapsin6_sockaddr(port, &addr);
787 		else
788 			*nam = in6_sockaddr(port, &addr6);
789 	}
790 	return error;
791 }
792 #endif /* INET6 */
793 
794 /*
795  * Mark the connection as being incapable of further output.
796  */
797 static int
798 tcp_usr_shutdown(struct socket *so)
799 {
800 	int error = 0;
801 	struct inpcb *inp;
802 	struct tcpcb *tp = NULL;
803 
804 	TCPDEBUG0;
805 	INP_INFO_RLOCK(&V_tcbinfo);
806 	inp = sotoinpcb(so);
807 	KASSERT(inp != NULL, ("inp == NULL"));
808 	INP_WLOCK(inp);
809 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
810 		error = ECONNRESET;
811 		goto out;
812 	}
813 	tp = intotcpcb(inp);
814 	TCPDEBUG1();
815 	socantsendmore(so);
816 	tcp_usrclosed(tp);
817 	if (!(inp->inp_flags & INP_DROPPED))
818 		error = tp->t_fb->tfb_tcp_output(tp);
819 
820 out:
821 	TCPDEBUG2(PRU_SHUTDOWN);
822 	TCP_PROBE2(debug__user, tp, PRU_SHUTDOWN);
823 	INP_WUNLOCK(inp);
824 	INP_INFO_RUNLOCK(&V_tcbinfo);
825 
826 	return (error);
827 }
828 
829 /*
830  * After a receive, possibly send window update to peer.
831  */
832 static int
833 tcp_usr_rcvd(struct socket *so, int flags)
834 {
835 	struct inpcb *inp;
836 	struct tcpcb *tp = NULL;
837 	int error = 0;
838 
839 	TCPDEBUG0;
840 	inp = sotoinpcb(so);
841 	KASSERT(inp != NULL, ("tcp_usr_rcvd: inp == NULL"));
842 	INP_WLOCK(inp);
843 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
844 		error = ECONNRESET;
845 		goto out;
846 	}
847 	tp = intotcpcb(inp);
848 	TCPDEBUG1();
849 #ifdef TCP_RFC7413
850 	/*
851 	 * For passively-created TFO connections, don't attempt a window
852 	 * update while still in SYN_RECEIVED as this may trigger an early
853 	 * SYN|ACK.  It is preferable to have the SYN|ACK be sent along with
854 	 * application response data, or failing that, when the DELACK timer
855 	 * expires.
856 	 */
857 	if (IS_FASTOPEN(tp->t_flags) &&
858 	    (tp->t_state == TCPS_SYN_RECEIVED))
859 		goto out;
860 #endif
861 #ifdef TCP_OFFLOAD
862 	if (tp->t_flags & TF_TOE)
863 		tcp_offload_rcvd(tp);
864 	else
865 #endif
866 	tp->t_fb->tfb_tcp_output(tp);
867 
868 out:
869 	TCPDEBUG2(PRU_RCVD);
870 	TCP_PROBE2(debug__user, tp, PRU_RCVD);
871 	INP_WUNLOCK(inp);
872 	return (error);
873 }
874 
875 /*
876  * Do a send by putting data in output queue and updating urgent
877  * marker if URG set.  Possibly send more data.  Unlike the other
878  * pru_*() routines, the mbuf chains are our responsibility.  We
879  * must either enqueue them or free them.  The other pru_* routines
880  * generally are caller-frees.
881  */
882 static int
883 tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
884     struct sockaddr *nam, struct mbuf *control, struct thread *td)
885 {
886 	int error = 0;
887 	struct inpcb *inp;
888 	struct tcpcb *tp = NULL;
889 #ifdef INET6
890 	int isipv6;
891 #endif
892 	TCPDEBUG0;
893 
894 	/*
895 	 * We require the pcbinfo lock if we will close the socket as part of
896 	 * this call.
897 	 */
898 	if (flags & PRUS_EOF)
899 		INP_INFO_RLOCK(&V_tcbinfo);
900 	inp = sotoinpcb(so);
901 	KASSERT(inp != NULL, ("tcp_usr_send: inp == NULL"));
902 	INP_WLOCK(inp);
903 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
904 		if (control)
905 			m_freem(control);
906 		/*
907 		 * In case of PRUS_NOTREADY, tcp_usr_ready() is responsible
908 		 * for freeing memory.
909 		 */
910 		if (m && (flags & PRUS_NOTREADY) == 0)
911 			m_freem(m);
912 		error = ECONNRESET;
913 		goto out;
914 	}
915 #ifdef INET6
916 	isipv6 = nam && nam->sa_family == AF_INET6;
917 #endif /* INET6 */
918 	tp = intotcpcb(inp);
919 	TCPDEBUG1();
920 	if (control) {
921 		/* TCP doesn't do control messages (rights, creds, etc) */
922 		if (control->m_len) {
923 			m_freem(control);
924 			if (m)
925 				m_freem(m);
926 			error = EINVAL;
927 			goto out;
928 		}
929 		m_freem(control);	/* empty control, just free it */
930 	}
931 	if (!(flags & PRUS_OOB)) {
932 		sbappendstream(&so->so_snd, m, flags);
933 		if (nam && tp->t_state < TCPS_SYN_SENT) {
934 			/*
935 			 * Do implied connect if not yet connected,
936 			 * initialize window to default value, and
937 			 * initialize maxseg using peer's cached MSS.
938 			 */
939 #ifdef INET6
940 			if (isipv6)
941 				error = tcp6_connect(tp, nam, td);
942 #endif /* INET6 */
943 #if defined(INET6) && defined(INET)
944 			else
945 #endif
946 #ifdef INET
947 				error = tcp_connect(tp, nam, td);
948 #endif
949 			if (error)
950 				goto out;
951 			tp->snd_wnd = TTCP_CLIENT_SND_WND;
952 			tcp_mss(tp, -1);
953 		}
954 		if (flags & PRUS_EOF) {
955 			/*
956 			 * Close the send side of the connection after
957 			 * the data is sent.
958 			 */
959 			INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
960 			socantsendmore(so);
961 			tcp_usrclosed(tp);
962 		}
963 		if (!(inp->inp_flags & INP_DROPPED) &&
964 		    !(flags & PRUS_NOTREADY)) {
965 			if (flags & PRUS_MORETOCOME)
966 				tp->t_flags |= TF_MORETOCOME;
967 			error = tp->t_fb->tfb_tcp_output(tp);
968 			if (flags & PRUS_MORETOCOME)
969 				tp->t_flags &= ~TF_MORETOCOME;
970 		}
971 	} else {
972 		/*
973 		 * XXXRW: PRUS_EOF not implemented with PRUS_OOB?
974 		 */
975 		SOCKBUF_LOCK(&so->so_snd);
976 		if (sbspace(&so->so_snd) < -512) {
977 			SOCKBUF_UNLOCK(&so->so_snd);
978 			m_freem(m);
979 			error = ENOBUFS;
980 			goto out;
981 		}
982 		/*
983 		 * According to RFC961 (Assigned Protocols),
984 		 * the urgent pointer points to the last octet
985 		 * of urgent data.  We continue, however,
986 		 * to consider it to indicate the first octet
987 		 * of data past the urgent section.
988 		 * Otherwise, snd_up should be one lower.
989 		 */
990 		sbappendstream_locked(&so->so_snd, m, flags);
991 		SOCKBUF_UNLOCK(&so->so_snd);
992 		if (nam && tp->t_state < TCPS_SYN_SENT) {
993 			/*
994 			 * Do implied connect if not yet connected,
995 			 * initialize window to default value, and
996 			 * initialize maxseg using peer's cached MSS.
997 			 */
998 #ifdef INET6
999 			if (isipv6)
1000 				error = tcp6_connect(tp, nam, td);
1001 #endif /* INET6 */
1002 #if defined(INET6) && defined(INET)
1003 			else
1004 #endif
1005 #ifdef INET
1006 				error = tcp_connect(tp, nam, td);
1007 #endif
1008 			if (error)
1009 				goto out;
1010 			tp->snd_wnd = TTCP_CLIENT_SND_WND;
1011 			tcp_mss(tp, -1);
1012 		}
1013 		tp->snd_up = tp->snd_una + sbavail(&so->so_snd);
1014 		if (!(flags & PRUS_NOTREADY)) {
1015 			tp->t_flags |= TF_FORCEDATA;
1016 			error = tp->t_fb->tfb_tcp_output(tp);
1017 			tp->t_flags &= ~TF_FORCEDATA;
1018 		}
1019 	}
1020 out:
1021 	TCPDEBUG2((flags & PRUS_OOB) ? PRU_SENDOOB :
1022 		  ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
1023 	TCP_PROBE2(debug__user, tp, (flags & PRUS_OOB) ? PRU_SENDOOB :
1024 		   ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
1025 	INP_WUNLOCK(inp);
1026 	if (flags & PRUS_EOF)
1027 		INP_INFO_RUNLOCK(&V_tcbinfo);
1028 	return (error);
1029 }
1030 
1031 static int
1032 tcp_usr_ready(struct socket *so, struct mbuf *m, int count)
1033 {
1034 	struct inpcb *inp;
1035 	struct tcpcb *tp;
1036 	int error;
1037 
1038 	inp = sotoinpcb(so);
1039 	INP_WLOCK(inp);
1040 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1041 		INP_WUNLOCK(inp);
1042 		for (int i = 0; i < count; i++)
1043 			m = m_free(m);
1044 		return (ECONNRESET);
1045 	}
1046 	tp = intotcpcb(inp);
1047 
1048 	SOCKBUF_LOCK(&so->so_snd);
1049 	error = sbready(&so->so_snd, m, count);
1050 	SOCKBUF_UNLOCK(&so->so_snd);
1051 	if (error == 0)
1052 		error = tp->t_fb->tfb_tcp_output(tp);
1053 	INP_WUNLOCK(inp);
1054 
1055 	return (error);
1056 }
1057 
1058 /*
1059  * Abort the TCP.  Drop the connection abruptly.
1060  */
1061 static void
1062 tcp_usr_abort(struct socket *so)
1063 {
1064 	struct inpcb *inp;
1065 	struct tcpcb *tp = NULL;
1066 	TCPDEBUG0;
1067 
1068 	inp = sotoinpcb(so);
1069 	KASSERT(inp != NULL, ("tcp_usr_abort: inp == NULL"));
1070 
1071 	INP_INFO_RLOCK(&V_tcbinfo);
1072 	INP_WLOCK(inp);
1073 	KASSERT(inp->inp_socket != NULL,
1074 	    ("tcp_usr_abort: inp_socket == NULL"));
1075 
1076 	/*
1077 	 * If we still have full TCP state, and we're not dropped, drop.
1078 	 */
1079 	if (!(inp->inp_flags & INP_TIMEWAIT) &&
1080 	    !(inp->inp_flags & INP_DROPPED)) {
1081 		tp = intotcpcb(inp);
1082 		TCPDEBUG1();
1083 		tcp_drop(tp, ECONNABORTED);
1084 		TCPDEBUG2(PRU_ABORT);
1085 		TCP_PROBE2(debug__user, tp, PRU_ABORT);
1086 	}
1087 	if (!(inp->inp_flags & INP_DROPPED)) {
1088 		SOCK_LOCK(so);
1089 		so->so_state |= SS_PROTOREF;
1090 		SOCK_UNLOCK(so);
1091 		inp->inp_flags |= INP_SOCKREF;
1092 	}
1093 	INP_WUNLOCK(inp);
1094 	INP_INFO_RUNLOCK(&V_tcbinfo);
1095 }
1096 
1097 /*
1098  * TCP socket is closed.  Start friendly disconnect.
1099  */
1100 static void
1101 tcp_usr_close(struct socket *so)
1102 {
1103 	struct inpcb *inp;
1104 	struct tcpcb *tp = NULL;
1105 	TCPDEBUG0;
1106 
1107 	inp = sotoinpcb(so);
1108 	KASSERT(inp != NULL, ("tcp_usr_close: inp == NULL"));
1109 
1110 	INP_INFO_RLOCK(&V_tcbinfo);
1111 	INP_WLOCK(inp);
1112 	KASSERT(inp->inp_socket != NULL,
1113 	    ("tcp_usr_close: inp_socket == NULL"));
1114 
1115 	/*
1116 	 * If we still have full TCP state, and we're not dropped, initiate
1117 	 * a disconnect.
1118 	 */
1119 	if (!(inp->inp_flags & INP_TIMEWAIT) &&
1120 	    !(inp->inp_flags & INP_DROPPED)) {
1121 		tp = intotcpcb(inp);
1122 		TCPDEBUG1();
1123 		tcp_disconnect(tp);
1124 		TCPDEBUG2(PRU_CLOSE);
1125 		TCP_PROBE2(debug__user, tp, PRU_CLOSE);
1126 	}
1127 	if (!(inp->inp_flags & INP_DROPPED)) {
1128 		SOCK_LOCK(so);
1129 		so->so_state |= SS_PROTOREF;
1130 		SOCK_UNLOCK(so);
1131 		inp->inp_flags |= INP_SOCKREF;
1132 	}
1133 	INP_WUNLOCK(inp);
1134 	INP_INFO_RUNLOCK(&V_tcbinfo);
1135 }
1136 
1137 /*
1138  * Receive out-of-band data.
1139  */
1140 static int
1141 tcp_usr_rcvoob(struct socket *so, struct mbuf *m, int flags)
1142 {
1143 	int error = 0;
1144 	struct inpcb *inp;
1145 	struct tcpcb *tp = NULL;
1146 
1147 	TCPDEBUG0;
1148 	inp = sotoinpcb(so);
1149 	KASSERT(inp != NULL, ("tcp_usr_rcvoob: inp == NULL"));
1150 	INP_WLOCK(inp);
1151 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1152 		error = ECONNRESET;
1153 		goto out;
1154 	}
1155 	tp = intotcpcb(inp);
1156 	TCPDEBUG1();
1157 	if ((so->so_oobmark == 0 &&
1158 	     (so->so_rcv.sb_state & SBS_RCVATMARK) == 0) ||
1159 	    so->so_options & SO_OOBINLINE ||
1160 	    tp->t_oobflags & TCPOOB_HADDATA) {
1161 		error = EINVAL;
1162 		goto out;
1163 	}
1164 	if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
1165 		error = EWOULDBLOCK;
1166 		goto out;
1167 	}
1168 	m->m_len = 1;
1169 	*mtod(m, caddr_t) = tp->t_iobc;
1170 	if ((flags & MSG_PEEK) == 0)
1171 		tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
1172 
1173 out:
1174 	TCPDEBUG2(PRU_RCVOOB);
1175 	TCP_PROBE2(debug__user, tp, PRU_RCVOOB);
1176 	INP_WUNLOCK(inp);
1177 	return (error);
1178 }
1179 
1180 #ifdef INET
1181 struct pr_usrreqs tcp_usrreqs = {
1182 	.pru_abort =		tcp_usr_abort,
1183 	.pru_accept =		tcp_usr_accept,
1184 	.pru_attach =		tcp_usr_attach,
1185 	.pru_bind =		tcp_usr_bind,
1186 	.pru_connect =		tcp_usr_connect,
1187 	.pru_control =		in_control,
1188 	.pru_detach =		tcp_usr_detach,
1189 	.pru_disconnect =	tcp_usr_disconnect,
1190 	.pru_listen =		tcp_usr_listen,
1191 	.pru_peeraddr =		in_getpeeraddr,
1192 	.pru_rcvd =		tcp_usr_rcvd,
1193 	.pru_rcvoob =		tcp_usr_rcvoob,
1194 	.pru_send =		tcp_usr_send,
1195 	.pru_ready =		tcp_usr_ready,
1196 	.pru_shutdown =		tcp_usr_shutdown,
1197 	.pru_sockaddr =		in_getsockaddr,
1198 	.pru_sosetlabel =	in_pcbsosetlabel,
1199 	.pru_close =		tcp_usr_close,
1200 };
1201 #endif /* INET */
1202 
1203 #ifdef INET6
1204 struct pr_usrreqs tcp6_usrreqs = {
1205 	.pru_abort =		tcp_usr_abort,
1206 	.pru_accept =		tcp6_usr_accept,
1207 	.pru_attach =		tcp_usr_attach,
1208 	.pru_bind =		tcp6_usr_bind,
1209 	.pru_connect =		tcp6_usr_connect,
1210 	.pru_control =		in6_control,
1211 	.pru_detach =		tcp_usr_detach,
1212 	.pru_disconnect =	tcp_usr_disconnect,
1213 	.pru_listen =		tcp6_usr_listen,
1214 	.pru_peeraddr =		in6_mapped_peeraddr,
1215 	.pru_rcvd =		tcp_usr_rcvd,
1216 	.pru_rcvoob =		tcp_usr_rcvoob,
1217 	.pru_send =		tcp_usr_send,
1218 	.pru_ready =		tcp_usr_ready,
1219 	.pru_shutdown =		tcp_usr_shutdown,
1220 	.pru_sockaddr =		in6_mapped_sockaddr,
1221 	.pru_sosetlabel =	in_pcbsosetlabel,
1222 	.pru_close =		tcp_usr_close,
1223 };
1224 #endif /* INET6 */
1225 
1226 #ifdef INET
1227 /*
1228  * Common subroutine to open a TCP connection to remote host specified
1229  * by struct sockaddr_in in mbuf *nam.  Call in_pcbbind to assign a local
1230  * port number if needed.  Call in_pcbconnect_setup to do the routing and
1231  * to choose a local host address (interface).  If there is an existing
1232  * incarnation of the same connection in TIME-WAIT state and if the remote
1233  * host was sending CC options and if the connection duration was < MSL, then
1234  * truncate the previous TIME-WAIT state and proceed.
1235  * Initialize connection parameters and enter SYN-SENT state.
1236  */
1237 static int
1238 tcp_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
1239 {
1240 	struct inpcb *inp = tp->t_inpcb, *oinp;
1241 	struct socket *so = inp->inp_socket;
1242 	struct in_addr laddr;
1243 	u_short lport;
1244 	int error;
1245 
1246 	INP_WLOCK_ASSERT(inp);
1247 	INP_HASH_WLOCK(&V_tcbinfo);
1248 
1249 	if (inp->inp_lport == 0) {
1250 		error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
1251 		if (error)
1252 			goto out;
1253 	}
1254 
1255 	/*
1256 	 * Cannot simply call in_pcbconnect, because there might be an
1257 	 * earlier incarnation of this same connection still in
1258 	 * TIME_WAIT state, creating an ADDRINUSE error.
1259 	 */
1260 	laddr = inp->inp_laddr;
1261 	lport = inp->inp_lport;
1262 	error = in_pcbconnect_setup(inp, nam, &laddr.s_addr, &lport,
1263 	    &inp->inp_faddr.s_addr, &inp->inp_fport, &oinp, td->td_ucred);
1264 	if (error && oinp == NULL)
1265 		goto out;
1266 	if (oinp) {
1267 		error = EADDRINUSE;
1268 		goto out;
1269 	}
1270 	inp->inp_laddr = laddr;
1271 	in_pcbrehash(inp);
1272 	INP_HASH_WUNLOCK(&V_tcbinfo);
1273 
1274 	/*
1275 	 * Compute window scaling to request:
1276 	 * Scale to fit into sweet spot.  See tcp_syncache.c.
1277 	 * XXX: This should move to tcp_output().
1278 	 */
1279 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1280 	    (TCP_MAXWIN << tp->request_r_scale) < sb_max)
1281 		tp->request_r_scale++;
1282 
1283 	soisconnecting(so);
1284 	TCPSTAT_INC(tcps_connattempt);
1285 	tcp_state_change(tp, TCPS_SYN_SENT);
1286 	tp->iss = tcp_new_isn(tp);
1287 	tcp_sendseqinit(tp);
1288 
1289 	return 0;
1290 
1291 out:
1292 	INP_HASH_WUNLOCK(&V_tcbinfo);
1293 	return (error);
1294 }
1295 #endif /* INET */
1296 
1297 #ifdef INET6
1298 static int
1299 tcp6_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
1300 {
1301 	struct inpcb *inp = tp->t_inpcb;
1302 	int error;
1303 
1304 	INP_WLOCK_ASSERT(inp);
1305 	INP_HASH_WLOCK(&V_tcbinfo);
1306 
1307 	if (inp->inp_lport == 0) {
1308 		error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
1309 		if (error)
1310 			goto out;
1311 	}
1312 	error = in6_pcbconnect(inp, nam, td->td_ucred);
1313 	if (error != 0)
1314 		goto out;
1315 	INP_HASH_WUNLOCK(&V_tcbinfo);
1316 
1317 	/* Compute window scaling to request.  */
1318 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1319 	    (TCP_MAXWIN << tp->request_r_scale) < sb_max)
1320 		tp->request_r_scale++;
1321 
1322 	soisconnecting(inp->inp_socket);
1323 	TCPSTAT_INC(tcps_connattempt);
1324 	tcp_state_change(tp, TCPS_SYN_SENT);
1325 	tp->iss = tcp_new_isn(tp);
1326 	tcp_sendseqinit(tp);
1327 
1328 	return 0;
1329 
1330 out:
1331 	INP_HASH_WUNLOCK(&V_tcbinfo);
1332 	return error;
1333 }
1334 #endif /* INET6 */
1335 
1336 /*
1337  * Export TCP internal state information via a struct tcp_info, based on the
1338  * Linux 2.6 API.  Not ABI compatible as our constants are mapped differently
1339  * (TCP state machine, etc).  We export all information using FreeBSD-native
1340  * constants -- for example, the numeric values for tcpi_state will differ
1341  * from Linux.
1342  */
1343 static void
1344 tcp_fill_info(struct tcpcb *tp, struct tcp_info *ti)
1345 {
1346 
1347 	INP_WLOCK_ASSERT(tp->t_inpcb);
1348 	bzero(ti, sizeof(*ti));
1349 
1350 	ti->tcpi_state = tp->t_state;
1351 	if ((tp->t_flags & TF_REQ_TSTMP) && (tp->t_flags & TF_RCVD_TSTMP))
1352 		ti->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1353 	if (tp->t_flags & TF_SACK_PERMIT)
1354 		ti->tcpi_options |= TCPI_OPT_SACK;
1355 	if ((tp->t_flags & TF_REQ_SCALE) && (tp->t_flags & TF_RCVD_SCALE)) {
1356 		ti->tcpi_options |= TCPI_OPT_WSCALE;
1357 		ti->tcpi_snd_wscale = tp->snd_scale;
1358 		ti->tcpi_rcv_wscale = tp->rcv_scale;
1359 	}
1360 	if (tp->t_flags & TF_ECN_PERMIT)
1361 		ti->tcpi_options |= TCPI_OPT_ECN;
1362 
1363 	ti->tcpi_rto = tp->t_rxtcur * tick;
1364 	ti->tcpi_last_data_recv = ((uint32_t)ticks - tp->t_rcvtime) * tick;
1365 	ti->tcpi_rtt = ((u_int64_t)tp->t_srtt * tick) >> TCP_RTT_SHIFT;
1366 	ti->tcpi_rttvar = ((u_int64_t)tp->t_rttvar * tick) >> TCP_RTTVAR_SHIFT;
1367 
1368 	ti->tcpi_snd_ssthresh = tp->snd_ssthresh;
1369 	ti->tcpi_snd_cwnd = tp->snd_cwnd;
1370 
1371 	/*
1372 	 * FreeBSD-specific extension fields for tcp_info.
1373 	 */
1374 	ti->tcpi_rcv_space = tp->rcv_wnd;
1375 	ti->tcpi_rcv_nxt = tp->rcv_nxt;
1376 	ti->tcpi_snd_wnd = tp->snd_wnd;
1377 	ti->tcpi_snd_bwnd = 0;		/* Unused, kept for compat. */
1378 	ti->tcpi_snd_nxt = tp->snd_nxt;
1379 	ti->tcpi_snd_mss = tp->t_maxseg;
1380 	ti->tcpi_rcv_mss = tp->t_maxseg;
1381 	if (tp->t_flags & TF_TOE)
1382 		ti->tcpi_options |= TCPI_OPT_TOE;
1383 	ti->tcpi_snd_rexmitpack = tp->t_sndrexmitpack;
1384 	ti->tcpi_rcv_ooopack = tp->t_rcvoopack;
1385 	ti->tcpi_snd_zerowin = tp->t_sndzerowin;
1386 }
1387 
1388 /*
1389  * tcp_ctloutput() must drop the inpcb lock before performing copyin on
1390  * socket option arguments.  When it re-acquires the lock after the copy, it
1391  * has to revalidate that the connection is still valid for the socket
1392  * option.
1393  */
1394 #define INP_WLOCK_RECHECK_CLEANUP(inp, cleanup) do {			\
1395 	INP_WLOCK(inp);							\
1396 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {		\
1397 		INP_WUNLOCK(inp);					\
1398 		cleanup;						\
1399 		return (ECONNRESET);					\
1400 	}								\
1401 	tp = intotcpcb(inp);						\
1402 } while(0)
1403 #define INP_WLOCK_RECHECK(inp) INP_WLOCK_RECHECK_CLEANUP((inp), /* noop */)
1404 
1405 int
1406 tcp_ctloutput(struct socket *so, struct sockopt *sopt)
1407 {
1408 	int	error;
1409 	struct	inpcb *inp;
1410 	struct	tcpcb *tp;
1411 	struct tcp_function_block *blk;
1412 	struct tcp_function_set fsn;
1413 
1414 	error = 0;
1415 	inp = sotoinpcb(so);
1416 	KASSERT(inp != NULL, ("tcp_ctloutput: inp == NULL"));
1417 	INP_WLOCK(inp);
1418 	if (sopt->sopt_level != IPPROTO_TCP) {
1419 #ifdef INET6
1420 		if (inp->inp_vflag & INP_IPV6PROTO) {
1421 			INP_WUNLOCK(inp);
1422 			error = ip6_ctloutput(so, sopt);
1423 		}
1424 #endif /* INET6 */
1425 #if defined(INET6) && defined(INET)
1426 		else
1427 #endif
1428 #ifdef INET
1429 		{
1430 			INP_WUNLOCK(inp);
1431 			error = ip_ctloutput(so, sopt);
1432 		}
1433 #endif
1434 		return (error);
1435 	}
1436 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1437 		INP_WUNLOCK(inp);
1438 		return (ECONNRESET);
1439 	}
1440 	tp = intotcpcb(inp);
1441 	/*
1442 	 * Protect the TCP option TCP_FUNCTION_BLK so
1443 	 * that a sub-function can *never* overwrite this.
1444 	 */
1445 	if ((sopt->sopt_dir == SOPT_SET) &&
1446 	    (sopt->sopt_name == TCP_FUNCTION_BLK)) {
1447 		INP_WUNLOCK(inp);
1448 		error = sooptcopyin(sopt, &fsn, sizeof fsn,
1449 		    sizeof fsn);
1450 		if (error)
1451 			return (error);
1452 		INP_WLOCK_RECHECK(inp);
1453 		blk = find_and_ref_tcp_functions(&fsn);
1454 		if (blk == NULL) {
1455 			INP_WUNLOCK(inp);
1456 			return (ENOENT);
1457 		}
1458 		if (tp->t_fb == blk) {
1459 			/* You already have this */
1460 			refcount_release(&blk->tfb_refcnt);
1461 			INP_WUNLOCK(inp);
1462 			return (0);
1463 		}
1464 		if (tp->t_state != TCPS_CLOSED) {
1465 			int error=EINVAL;
1466 			/*
1467 			 * The user has advanced the state
1468 			 * past the initial point, we may not
1469 			 * be able to switch.
1470 			 */
1471 			if (blk->tfb_tcp_handoff_ok != NULL) {
1472 				/*
1473 				 * Does the stack provide a
1474 				 * query mechanism, if so it may
1475 				 * still be possible?
1476 				 */
1477 				error = (*blk->tfb_tcp_handoff_ok)(tp);
1478 			}
1479 			if (error) {
1480 				refcount_release(&blk->tfb_refcnt);
1481 				INP_WUNLOCK(inp);
1482 				return(error);
1483 			}
1484 		}
1485 		if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
1486 			refcount_release(&blk->tfb_refcnt);
1487 			INP_WUNLOCK(inp);
1488 			return (ENOENT);
1489 		}
1490 		/*
1491 		 * Release the old refcnt, the
1492 		 * lookup acquired a ref on the
1493 		 * new one already.
1494 		 */
1495 		if (tp->t_fb->tfb_tcp_fb_fini) {
1496 			/*
1497 			 * Tell the stack to cleanup with 0 i.e.
1498 			 * the tcb is not going away.
1499 			 */
1500 			(*tp->t_fb->tfb_tcp_fb_fini)(tp, 0);
1501 		}
1502 		refcount_release(&tp->t_fb->tfb_refcnt);
1503 		tp->t_fb = blk;
1504 		if (tp->t_fb->tfb_tcp_fb_init) {
1505 			(*tp->t_fb->tfb_tcp_fb_init)(tp);
1506 		}
1507 #ifdef TCP_OFFLOAD
1508 		if (tp->t_flags & TF_TOE) {
1509 			tcp_offload_ctloutput(tp, sopt->sopt_dir,
1510 			     sopt->sopt_name);
1511 		}
1512 #endif
1513 		INP_WUNLOCK(inp);
1514 		return (error);
1515 	} else if ((sopt->sopt_dir == SOPT_GET) &&
1516 	    (sopt->sopt_name == TCP_FUNCTION_BLK)) {
1517 		strcpy(fsn.function_set_name, tp->t_fb->tfb_tcp_block_name);
1518 		fsn.pcbcnt = tp->t_fb->tfb_refcnt;
1519 		INP_WUNLOCK(inp);
1520 		error = sooptcopyout(sopt, &fsn, sizeof fsn);
1521 		return (error);
1522 	}
1523 	/* Pass in the INP locked, called must unlock it */
1524 	return (tp->t_fb->tfb_tcp_ctloutput(so, sopt, inp, tp));
1525 }
1526 
1527 int
1528 tcp_default_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp)
1529 {
1530 	int	error, opt, optval;
1531 	u_int	ui;
1532 	struct	tcp_info ti;
1533 	struct cc_algo *algo;
1534 	char	*pbuf, buf[TCP_CA_NAME_MAX];
1535 	size_t	len;
1536 
1537 	/*
1538 	 * For TCP_CCALGOOPT forward the control to CC module, for both
1539 	 * SOPT_SET and SOPT_GET.
1540 	 */
1541 	switch (sopt->sopt_name) {
1542 	case TCP_CCALGOOPT:
1543 		INP_WUNLOCK(inp);
1544 		pbuf = malloc(sopt->sopt_valsize, M_TEMP, M_WAITOK | M_ZERO);
1545 		error = sooptcopyin(sopt, pbuf, sopt->sopt_valsize,
1546 		    sopt->sopt_valsize);
1547 		if (error) {
1548 			free(pbuf, M_TEMP);
1549 			return (error);
1550 		}
1551 		INP_WLOCK_RECHECK_CLEANUP(inp, free(pbuf, M_TEMP));
1552 		if (CC_ALGO(tp)->ctl_output != NULL)
1553 			error = CC_ALGO(tp)->ctl_output(tp->ccv, sopt, pbuf);
1554 		else
1555 			error = ENOENT;
1556 		INP_WUNLOCK(inp);
1557 		if (error == 0 && sopt->sopt_dir == SOPT_GET)
1558 			error = sooptcopyout(sopt, pbuf, sopt->sopt_valsize);
1559 		free(pbuf, M_TEMP);
1560 		return (error);
1561 	}
1562 
1563 	switch (sopt->sopt_dir) {
1564 	case SOPT_SET:
1565 		switch (sopt->sopt_name) {
1566 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
1567 		case TCP_MD5SIG:
1568 			if (!TCPMD5_ENABLED()) {
1569 				INP_WUNLOCK(inp);
1570 				return (ENOPROTOOPT);
1571 			}
1572 			error = TCPMD5_PCBCTL(inp, sopt);
1573 			if (error)
1574 				return (error);
1575 			goto unlock_and_done;
1576 #endif /* IPSEC */
1577 
1578 		case TCP_NODELAY:
1579 		case TCP_NOOPT:
1580 			INP_WUNLOCK(inp);
1581 			error = sooptcopyin(sopt, &optval, sizeof optval,
1582 			    sizeof optval);
1583 			if (error)
1584 				return (error);
1585 
1586 			INP_WLOCK_RECHECK(inp);
1587 			switch (sopt->sopt_name) {
1588 			case TCP_NODELAY:
1589 				opt = TF_NODELAY;
1590 				break;
1591 			case TCP_NOOPT:
1592 				opt = TF_NOOPT;
1593 				break;
1594 			default:
1595 				opt = 0; /* dead code to fool gcc */
1596 				break;
1597 			}
1598 
1599 			if (optval)
1600 				tp->t_flags |= opt;
1601 			else
1602 				tp->t_flags &= ~opt;
1603 unlock_and_done:
1604 #ifdef TCP_OFFLOAD
1605 			if (tp->t_flags & TF_TOE) {
1606 				tcp_offload_ctloutput(tp, sopt->sopt_dir,
1607 				    sopt->sopt_name);
1608 			}
1609 #endif
1610 			INP_WUNLOCK(inp);
1611 			break;
1612 
1613 		case TCP_NOPUSH:
1614 			INP_WUNLOCK(inp);
1615 			error = sooptcopyin(sopt, &optval, sizeof optval,
1616 			    sizeof optval);
1617 			if (error)
1618 				return (error);
1619 
1620 			INP_WLOCK_RECHECK(inp);
1621 			if (optval)
1622 				tp->t_flags |= TF_NOPUSH;
1623 			else if (tp->t_flags & TF_NOPUSH) {
1624 				tp->t_flags &= ~TF_NOPUSH;
1625 				if (TCPS_HAVEESTABLISHED(tp->t_state))
1626 					error = tp->t_fb->tfb_tcp_output(tp);
1627 			}
1628 			goto unlock_and_done;
1629 
1630 		case TCP_MAXSEG:
1631 			INP_WUNLOCK(inp);
1632 			error = sooptcopyin(sopt, &optval, sizeof optval,
1633 			    sizeof optval);
1634 			if (error)
1635 				return (error);
1636 
1637 			INP_WLOCK_RECHECK(inp);
1638 			if (optval > 0 && optval <= tp->t_maxseg &&
1639 			    optval + 40 >= V_tcp_minmss)
1640 				tp->t_maxseg = optval;
1641 			else
1642 				error = EINVAL;
1643 			goto unlock_and_done;
1644 
1645 		case TCP_INFO:
1646 			INP_WUNLOCK(inp);
1647 			error = EINVAL;
1648 			break;
1649 
1650 		case TCP_CONGESTION:
1651 			INP_WUNLOCK(inp);
1652 			error = sooptcopyin(sopt, buf, TCP_CA_NAME_MAX - 1, 1);
1653 			if (error)
1654 				break;
1655 			buf[sopt->sopt_valsize] = '\0';
1656 			INP_WLOCK_RECHECK(inp);
1657 			CC_LIST_RLOCK();
1658 			STAILQ_FOREACH(algo, &cc_list, entries)
1659 				if (strncmp(buf, algo->name,
1660 				    TCP_CA_NAME_MAX) == 0)
1661 					break;
1662 			CC_LIST_RUNLOCK();
1663 			if (algo == NULL) {
1664 				INP_WUNLOCK(inp);
1665 				error = EINVAL;
1666 				break;
1667 			}
1668 			/*
1669 			 * We hold a write lock over the tcb so it's safe to
1670 			 * do these things without ordering concerns.
1671 			 */
1672 			if (CC_ALGO(tp)->cb_destroy != NULL)
1673 				CC_ALGO(tp)->cb_destroy(tp->ccv);
1674 			CC_ALGO(tp) = algo;
1675 			/*
1676 			 * If something goes pear shaped initialising the new
1677 			 * algo, fall back to newreno (which does not
1678 			 * require initialisation).
1679 			 */
1680 			if (algo->cb_init != NULL &&
1681 			    algo->cb_init(tp->ccv) != 0) {
1682 				CC_ALGO(tp) = &newreno_cc_algo;
1683 				/*
1684 				 * The only reason init should fail is
1685 				 * because of malloc.
1686 				 */
1687 				error = ENOMEM;
1688 			}
1689 			INP_WUNLOCK(inp);
1690 			break;
1691 
1692 		case TCP_KEEPIDLE:
1693 		case TCP_KEEPINTVL:
1694 		case TCP_KEEPINIT:
1695 			INP_WUNLOCK(inp);
1696 			error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
1697 			if (error)
1698 				return (error);
1699 
1700 			if (ui > (UINT_MAX / hz)) {
1701 				error = EINVAL;
1702 				break;
1703 			}
1704 			ui *= hz;
1705 
1706 			INP_WLOCK_RECHECK(inp);
1707 			switch (sopt->sopt_name) {
1708 			case TCP_KEEPIDLE:
1709 				tp->t_keepidle = ui;
1710 				/*
1711 				 * XXX: better check current remaining
1712 				 * timeout and "merge" it with new value.
1713 				 */
1714 				if ((tp->t_state > TCPS_LISTEN) &&
1715 				    (tp->t_state <= TCPS_CLOSING))
1716 					tcp_timer_activate(tp, TT_KEEP,
1717 					    TP_KEEPIDLE(tp));
1718 				break;
1719 			case TCP_KEEPINTVL:
1720 				tp->t_keepintvl = ui;
1721 				if ((tp->t_state == TCPS_FIN_WAIT_2) &&
1722 				    (TP_MAXIDLE(tp) > 0))
1723 					tcp_timer_activate(tp, TT_2MSL,
1724 					    TP_MAXIDLE(tp));
1725 				break;
1726 			case TCP_KEEPINIT:
1727 				tp->t_keepinit = ui;
1728 				if (tp->t_state == TCPS_SYN_RECEIVED ||
1729 				    tp->t_state == TCPS_SYN_SENT)
1730 					tcp_timer_activate(tp, TT_KEEP,
1731 					    TP_KEEPINIT(tp));
1732 				break;
1733 			}
1734 			goto unlock_and_done;
1735 
1736 		case TCP_KEEPCNT:
1737 			INP_WUNLOCK(inp);
1738 			error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
1739 			if (error)
1740 				return (error);
1741 
1742 			INP_WLOCK_RECHECK(inp);
1743 			tp->t_keepcnt = ui;
1744 			if ((tp->t_state == TCPS_FIN_WAIT_2) &&
1745 			    (TP_MAXIDLE(tp) > 0))
1746 				tcp_timer_activate(tp, TT_2MSL,
1747 				    TP_MAXIDLE(tp));
1748 			goto unlock_and_done;
1749 
1750 #ifdef TCPPCAP
1751 		case TCP_PCAP_OUT:
1752 		case TCP_PCAP_IN:
1753 			INP_WUNLOCK(inp);
1754 			error = sooptcopyin(sopt, &optval, sizeof optval,
1755 			    sizeof optval);
1756 			if (error)
1757 				return (error);
1758 
1759 			INP_WLOCK_RECHECK(inp);
1760 			if (optval >= 0)
1761 				tcp_pcap_set_sock_max(TCP_PCAP_OUT ?
1762 					&(tp->t_outpkts) : &(tp->t_inpkts),
1763 					optval);
1764 			else
1765 				error = EINVAL;
1766 			goto unlock_and_done;
1767 #endif
1768 
1769 #ifdef TCP_RFC7413
1770 		case TCP_FASTOPEN:
1771 			INP_WUNLOCK(inp);
1772 			if (!V_tcp_fastopen_enabled)
1773 				return (EPERM);
1774 
1775 			error = sooptcopyin(sopt, &optval, sizeof optval,
1776 			    sizeof optval);
1777 			if (error)
1778 				return (error);
1779 
1780 			INP_WLOCK_RECHECK(inp);
1781 			if (optval) {
1782 				tp->t_flags |= TF_FASTOPEN;
1783 				if ((tp->t_state == TCPS_LISTEN) &&
1784 				    (tp->t_tfo_pending == NULL))
1785 					tp->t_tfo_pending =
1786 					    tcp_fastopen_alloc_counter();
1787 			} else
1788 				tp->t_flags &= ~TF_FASTOPEN;
1789 			goto unlock_and_done;
1790 #endif
1791 
1792 		default:
1793 			INP_WUNLOCK(inp);
1794 			error = ENOPROTOOPT;
1795 			break;
1796 		}
1797 		break;
1798 
1799 	case SOPT_GET:
1800 		tp = intotcpcb(inp);
1801 		switch (sopt->sopt_name) {
1802 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
1803 		case TCP_MD5SIG:
1804 			if (!TCPMD5_ENABLED()) {
1805 				INP_WUNLOCK(inp);
1806 				return (ENOPROTOOPT);
1807 			}
1808 			error = TCPMD5_PCBCTL(inp, sopt);
1809 			break;
1810 #endif
1811 
1812 		case TCP_NODELAY:
1813 			optval = tp->t_flags & TF_NODELAY;
1814 			INP_WUNLOCK(inp);
1815 			error = sooptcopyout(sopt, &optval, sizeof optval);
1816 			break;
1817 		case TCP_MAXSEG:
1818 			optval = tp->t_maxseg;
1819 			INP_WUNLOCK(inp);
1820 			error = sooptcopyout(sopt, &optval, sizeof optval);
1821 			break;
1822 		case TCP_NOOPT:
1823 			optval = tp->t_flags & TF_NOOPT;
1824 			INP_WUNLOCK(inp);
1825 			error = sooptcopyout(sopt, &optval, sizeof optval);
1826 			break;
1827 		case TCP_NOPUSH:
1828 			optval = tp->t_flags & TF_NOPUSH;
1829 			INP_WUNLOCK(inp);
1830 			error = sooptcopyout(sopt, &optval, sizeof optval);
1831 			break;
1832 		case TCP_INFO:
1833 			tcp_fill_info(tp, &ti);
1834 			INP_WUNLOCK(inp);
1835 			error = sooptcopyout(sopt, &ti, sizeof ti);
1836 			break;
1837 		case TCP_CONGESTION:
1838 			len = strlcpy(buf, CC_ALGO(tp)->name, TCP_CA_NAME_MAX);
1839 			INP_WUNLOCK(inp);
1840 			error = sooptcopyout(sopt, buf, len + 1);
1841 			break;
1842 		case TCP_KEEPIDLE:
1843 		case TCP_KEEPINTVL:
1844 		case TCP_KEEPINIT:
1845 		case TCP_KEEPCNT:
1846 			switch (sopt->sopt_name) {
1847 			case TCP_KEEPIDLE:
1848 				ui = TP_KEEPIDLE(tp) / hz;
1849 				break;
1850 			case TCP_KEEPINTVL:
1851 				ui = TP_KEEPINTVL(tp) / hz;
1852 				break;
1853 			case TCP_KEEPINIT:
1854 				ui = TP_KEEPINIT(tp) / hz;
1855 				break;
1856 			case TCP_KEEPCNT:
1857 				ui = TP_KEEPCNT(tp);
1858 				break;
1859 			}
1860 			INP_WUNLOCK(inp);
1861 			error = sooptcopyout(sopt, &ui, sizeof(ui));
1862 			break;
1863 #ifdef TCPPCAP
1864 		case TCP_PCAP_OUT:
1865 		case TCP_PCAP_IN:
1866 			optval = tcp_pcap_get_sock_max(TCP_PCAP_OUT ?
1867 					&(tp->t_outpkts) : &(tp->t_inpkts));
1868 			INP_WUNLOCK(inp);
1869 			error = sooptcopyout(sopt, &optval, sizeof optval);
1870 			break;
1871 #endif
1872 
1873 #ifdef TCP_RFC7413
1874 		case TCP_FASTOPEN:
1875 			optval = tp->t_flags & TF_FASTOPEN;
1876 			INP_WUNLOCK(inp);
1877 			error = sooptcopyout(sopt, &optval, sizeof optval);
1878 			break;
1879 #endif
1880 		default:
1881 			INP_WUNLOCK(inp);
1882 			error = ENOPROTOOPT;
1883 			break;
1884 		}
1885 		break;
1886 	}
1887 	return (error);
1888 }
1889 #undef INP_WLOCK_RECHECK
1890 #undef INP_WLOCK_RECHECK_CLEANUP
1891 
1892 /*
1893  * Attach TCP protocol to socket, allocating
1894  * internet protocol control block, tcp control block,
1895  * bufer space, and entering LISTEN state if to accept connections.
1896  */
1897 static int
1898 tcp_attach(struct socket *so)
1899 {
1900 	struct tcpcb *tp;
1901 	struct inpcb *inp;
1902 	int error;
1903 
1904 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
1905 		error = soreserve(so, V_tcp_sendspace, V_tcp_recvspace);
1906 		if (error)
1907 			return (error);
1908 	}
1909 	so->so_rcv.sb_flags |= SB_AUTOSIZE;
1910 	so->so_snd.sb_flags |= SB_AUTOSIZE;
1911 	INP_INFO_RLOCK(&V_tcbinfo);
1912 	error = in_pcballoc(so, &V_tcbinfo);
1913 	if (error) {
1914 		INP_INFO_RUNLOCK(&V_tcbinfo);
1915 		return (error);
1916 	}
1917 	inp = sotoinpcb(so);
1918 #ifdef INET6
1919 	if (inp->inp_vflag & INP_IPV6PROTO) {
1920 		inp->inp_vflag |= INP_IPV6;
1921 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
1922 			inp->inp_vflag |= INP_IPV4;
1923 		inp->in6p_hops = -1;	/* use kernel default */
1924 	}
1925 	else
1926 #endif
1927 	inp->inp_vflag |= INP_IPV4;
1928 	tp = tcp_newtcpcb(inp);
1929 	if (tp == NULL) {
1930 		in_pcbdetach(inp);
1931 		in_pcbfree(inp);
1932 		INP_INFO_RUNLOCK(&V_tcbinfo);
1933 		return (ENOBUFS);
1934 	}
1935 	tp->t_state = TCPS_CLOSED;
1936 	INP_WUNLOCK(inp);
1937 	INP_INFO_RUNLOCK(&V_tcbinfo);
1938 	TCPSTATES_INC(TCPS_CLOSED);
1939 	return (0);
1940 }
1941 
1942 /*
1943  * Initiate (or continue) disconnect.
1944  * If embryonic state, just send reset (once).
1945  * If in ``let data drain'' option and linger null, just drop.
1946  * Otherwise (hard), mark socket disconnecting and drop
1947  * current input data; switch states based on user close, and
1948  * send segment to peer (with FIN).
1949  */
1950 static void
1951 tcp_disconnect(struct tcpcb *tp)
1952 {
1953 	struct inpcb *inp = tp->t_inpcb;
1954 	struct socket *so = inp->inp_socket;
1955 
1956 	INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
1957 	INP_WLOCK_ASSERT(inp);
1958 
1959 	/*
1960 	 * Neither tcp_close() nor tcp_drop() should return NULL, as the
1961 	 * socket is still open.
1962 	 */
1963 	if (tp->t_state < TCPS_ESTABLISHED) {
1964 		tp = tcp_close(tp);
1965 		KASSERT(tp != NULL,
1966 		    ("tcp_disconnect: tcp_close() returned NULL"));
1967 	} else if ((so->so_options & SO_LINGER) && so->so_linger == 0) {
1968 		tp = tcp_drop(tp, 0);
1969 		KASSERT(tp != NULL,
1970 		    ("tcp_disconnect: tcp_drop() returned NULL"));
1971 	} else {
1972 		soisdisconnecting(so);
1973 		sbflush(&so->so_rcv);
1974 		tcp_usrclosed(tp);
1975 		if (!(inp->inp_flags & INP_DROPPED))
1976 			tp->t_fb->tfb_tcp_output(tp);
1977 	}
1978 }
1979 
1980 /*
1981  * User issued close, and wish to trail through shutdown states:
1982  * if never received SYN, just forget it.  If got a SYN from peer,
1983  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
1984  * If already got a FIN from peer, then almost done; go to LAST_ACK
1985  * state.  In all other cases, have already sent FIN to peer (e.g.
1986  * after PRU_SHUTDOWN), and just have to play tedious game waiting
1987  * for peer to send FIN or not respond to keep-alives, etc.
1988  * We can let the user exit from the close as soon as the FIN is acked.
1989  */
1990 static void
1991 tcp_usrclosed(struct tcpcb *tp)
1992 {
1993 
1994 	INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
1995 	INP_WLOCK_ASSERT(tp->t_inpcb);
1996 
1997 	switch (tp->t_state) {
1998 	case TCPS_LISTEN:
1999 #ifdef TCP_OFFLOAD
2000 		tcp_offload_listen_stop(tp);
2001 #endif
2002 		tcp_state_change(tp, TCPS_CLOSED);
2003 		/* FALLTHROUGH */
2004 	case TCPS_CLOSED:
2005 		tp = tcp_close(tp);
2006 		/*
2007 		 * tcp_close() should never return NULL here as the socket is
2008 		 * still open.
2009 		 */
2010 		KASSERT(tp != NULL,
2011 		    ("tcp_usrclosed: tcp_close() returned NULL"));
2012 		break;
2013 
2014 	case TCPS_SYN_SENT:
2015 	case TCPS_SYN_RECEIVED:
2016 		tp->t_flags |= TF_NEEDFIN;
2017 		break;
2018 
2019 	case TCPS_ESTABLISHED:
2020 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
2021 		break;
2022 
2023 	case TCPS_CLOSE_WAIT:
2024 		tcp_state_change(tp, TCPS_LAST_ACK);
2025 		break;
2026 	}
2027 	if (tp->t_state >= TCPS_FIN_WAIT_2) {
2028 		soisdisconnected(tp->t_inpcb->inp_socket);
2029 		/* Prevent the connection hanging in FIN_WAIT_2 forever. */
2030 		if (tp->t_state == TCPS_FIN_WAIT_2) {
2031 			int timeout;
2032 
2033 			timeout = (tcp_fast_finwait2_recycle) ?
2034 			    tcp_finwait2_timeout : TP_MAXIDLE(tp);
2035 			tcp_timer_activate(tp, TT_2MSL, timeout);
2036 		}
2037 	}
2038 }
2039 
2040 #ifdef DDB
2041 static void
2042 db_print_indent(int indent)
2043 {
2044 	int i;
2045 
2046 	for (i = 0; i < indent; i++)
2047 		db_printf(" ");
2048 }
2049 
2050 static void
2051 db_print_tstate(int t_state)
2052 {
2053 
2054 	switch (t_state) {
2055 	case TCPS_CLOSED:
2056 		db_printf("TCPS_CLOSED");
2057 		return;
2058 
2059 	case TCPS_LISTEN:
2060 		db_printf("TCPS_LISTEN");
2061 		return;
2062 
2063 	case TCPS_SYN_SENT:
2064 		db_printf("TCPS_SYN_SENT");
2065 		return;
2066 
2067 	case TCPS_SYN_RECEIVED:
2068 		db_printf("TCPS_SYN_RECEIVED");
2069 		return;
2070 
2071 	case TCPS_ESTABLISHED:
2072 		db_printf("TCPS_ESTABLISHED");
2073 		return;
2074 
2075 	case TCPS_CLOSE_WAIT:
2076 		db_printf("TCPS_CLOSE_WAIT");
2077 		return;
2078 
2079 	case TCPS_FIN_WAIT_1:
2080 		db_printf("TCPS_FIN_WAIT_1");
2081 		return;
2082 
2083 	case TCPS_CLOSING:
2084 		db_printf("TCPS_CLOSING");
2085 		return;
2086 
2087 	case TCPS_LAST_ACK:
2088 		db_printf("TCPS_LAST_ACK");
2089 		return;
2090 
2091 	case TCPS_FIN_WAIT_2:
2092 		db_printf("TCPS_FIN_WAIT_2");
2093 		return;
2094 
2095 	case TCPS_TIME_WAIT:
2096 		db_printf("TCPS_TIME_WAIT");
2097 		return;
2098 
2099 	default:
2100 		db_printf("unknown");
2101 		return;
2102 	}
2103 }
2104 
2105 static void
2106 db_print_tflags(u_int t_flags)
2107 {
2108 	int comma;
2109 
2110 	comma = 0;
2111 	if (t_flags & TF_ACKNOW) {
2112 		db_printf("%sTF_ACKNOW", comma ? ", " : "");
2113 		comma = 1;
2114 	}
2115 	if (t_flags & TF_DELACK) {
2116 		db_printf("%sTF_DELACK", comma ? ", " : "");
2117 		comma = 1;
2118 	}
2119 	if (t_flags & TF_NODELAY) {
2120 		db_printf("%sTF_NODELAY", comma ? ", " : "");
2121 		comma = 1;
2122 	}
2123 	if (t_flags & TF_NOOPT) {
2124 		db_printf("%sTF_NOOPT", comma ? ", " : "");
2125 		comma = 1;
2126 	}
2127 	if (t_flags & TF_SENTFIN) {
2128 		db_printf("%sTF_SENTFIN", comma ? ", " : "");
2129 		comma = 1;
2130 	}
2131 	if (t_flags & TF_REQ_SCALE) {
2132 		db_printf("%sTF_REQ_SCALE", comma ? ", " : "");
2133 		comma = 1;
2134 	}
2135 	if (t_flags & TF_RCVD_SCALE) {
2136 		db_printf("%sTF_RECVD_SCALE", comma ? ", " : "");
2137 		comma = 1;
2138 	}
2139 	if (t_flags & TF_REQ_TSTMP) {
2140 		db_printf("%sTF_REQ_TSTMP", comma ? ", " : "");
2141 		comma = 1;
2142 	}
2143 	if (t_flags & TF_RCVD_TSTMP) {
2144 		db_printf("%sTF_RCVD_TSTMP", comma ? ", " : "");
2145 		comma = 1;
2146 	}
2147 	if (t_flags & TF_SACK_PERMIT) {
2148 		db_printf("%sTF_SACK_PERMIT", comma ? ", " : "");
2149 		comma = 1;
2150 	}
2151 	if (t_flags & TF_NEEDSYN) {
2152 		db_printf("%sTF_NEEDSYN", comma ? ", " : "");
2153 		comma = 1;
2154 	}
2155 	if (t_flags & TF_NEEDFIN) {
2156 		db_printf("%sTF_NEEDFIN", comma ? ", " : "");
2157 		comma = 1;
2158 	}
2159 	if (t_flags & TF_NOPUSH) {
2160 		db_printf("%sTF_NOPUSH", comma ? ", " : "");
2161 		comma = 1;
2162 	}
2163 	if (t_flags & TF_MORETOCOME) {
2164 		db_printf("%sTF_MORETOCOME", comma ? ", " : "");
2165 		comma = 1;
2166 	}
2167 	if (t_flags & TF_LQ_OVERFLOW) {
2168 		db_printf("%sTF_LQ_OVERFLOW", comma ? ", " : "");
2169 		comma = 1;
2170 	}
2171 	if (t_flags & TF_LASTIDLE) {
2172 		db_printf("%sTF_LASTIDLE", comma ? ", " : "");
2173 		comma = 1;
2174 	}
2175 	if (t_flags & TF_RXWIN0SENT) {
2176 		db_printf("%sTF_RXWIN0SENT", comma ? ", " : "");
2177 		comma = 1;
2178 	}
2179 	if (t_flags & TF_FASTRECOVERY) {
2180 		db_printf("%sTF_FASTRECOVERY", comma ? ", " : "");
2181 		comma = 1;
2182 	}
2183 	if (t_flags & TF_CONGRECOVERY) {
2184 		db_printf("%sTF_CONGRECOVERY", comma ? ", " : "");
2185 		comma = 1;
2186 	}
2187 	if (t_flags & TF_WASFRECOVERY) {
2188 		db_printf("%sTF_WASFRECOVERY", comma ? ", " : "");
2189 		comma = 1;
2190 	}
2191 	if (t_flags & TF_SIGNATURE) {
2192 		db_printf("%sTF_SIGNATURE", comma ? ", " : "");
2193 		comma = 1;
2194 	}
2195 	if (t_flags & TF_FORCEDATA) {
2196 		db_printf("%sTF_FORCEDATA", comma ? ", " : "");
2197 		comma = 1;
2198 	}
2199 	if (t_flags & TF_TSO) {
2200 		db_printf("%sTF_TSO", comma ? ", " : "");
2201 		comma = 1;
2202 	}
2203 	if (t_flags & TF_ECN_PERMIT) {
2204 		db_printf("%sTF_ECN_PERMIT", comma ? ", " : "");
2205 		comma = 1;
2206 	}
2207 	if (t_flags & TF_FASTOPEN) {
2208 		db_printf("%sTF_FASTOPEN", comma ? ", " : "");
2209 		comma = 1;
2210 	}
2211 }
2212 
2213 static void
2214 db_print_toobflags(char t_oobflags)
2215 {
2216 	int comma;
2217 
2218 	comma = 0;
2219 	if (t_oobflags & TCPOOB_HAVEDATA) {
2220 		db_printf("%sTCPOOB_HAVEDATA", comma ? ", " : "");
2221 		comma = 1;
2222 	}
2223 	if (t_oobflags & TCPOOB_HADDATA) {
2224 		db_printf("%sTCPOOB_HADDATA", comma ? ", " : "");
2225 		comma = 1;
2226 	}
2227 }
2228 
2229 static void
2230 db_print_tcpcb(struct tcpcb *tp, const char *name, int indent)
2231 {
2232 
2233 	db_print_indent(indent);
2234 	db_printf("%s at %p\n", name, tp);
2235 
2236 	indent += 2;
2237 
2238 	db_print_indent(indent);
2239 	db_printf("t_segq first: %p   t_segqlen: %d   t_dupacks: %d\n",
2240 	   LIST_FIRST(&tp->t_segq), tp->t_segqlen, tp->t_dupacks);
2241 
2242 	db_print_indent(indent);
2243 	db_printf("tt_rexmt: %p   tt_persist: %p   tt_keep: %p\n",
2244 	    &tp->t_timers->tt_rexmt, &tp->t_timers->tt_persist, &tp->t_timers->tt_keep);
2245 
2246 	db_print_indent(indent);
2247 	db_printf("tt_2msl: %p   tt_delack: %p   t_inpcb: %p\n", &tp->t_timers->tt_2msl,
2248 	    &tp->t_timers->tt_delack, tp->t_inpcb);
2249 
2250 	db_print_indent(indent);
2251 	db_printf("t_state: %d (", tp->t_state);
2252 	db_print_tstate(tp->t_state);
2253 	db_printf(")\n");
2254 
2255 	db_print_indent(indent);
2256 	db_printf("t_flags: 0x%x (", tp->t_flags);
2257 	db_print_tflags(tp->t_flags);
2258 	db_printf(")\n");
2259 
2260 	db_print_indent(indent);
2261 	db_printf("snd_una: 0x%08x   snd_max: 0x%08x   snd_nxt: x0%08x\n",
2262 	    tp->snd_una, tp->snd_max, tp->snd_nxt);
2263 
2264 	db_print_indent(indent);
2265 	db_printf("snd_up: 0x%08x   snd_wl1: 0x%08x   snd_wl2: 0x%08x\n",
2266 	   tp->snd_up, tp->snd_wl1, tp->snd_wl2);
2267 
2268 	db_print_indent(indent);
2269 	db_printf("iss: 0x%08x   irs: 0x%08x   rcv_nxt: 0x%08x\n",
2270 	    tp->iss, tp->irs, tp->rcv_nxt);
2271 
2272 	db_print_indent(indent);
2273 	db_printf("rcv_adv: 0x%08x   rcv_wnd: %u   rcv_up: 0x%08x\n",
2274 	    tp->rcv_adv, tp->rcv_wnd, tp->rcv_up);
2275 
2276 	db_print_indent(indent);
2277 	db_printf("snd_wnd: %u   snd_cwnd: %u\n",
2278 	   tp->snd_wnd, tp->snd_cwnd);
2279 
2280 	db_print_indent(indent);
2281 	db_printf("snd_ssthresh: %u   snd_recover: "
2282 	    "0x%08x\n", tp->snd_ssthresh, tp->snd_recover);
2283 
2284 	db_print_indent(indent);
2285 	db_printf("t_rcvtime: %u   t_startime: %u\n",
2286 	    tp->t_rcvtime, tp->t_starttime);
2287 
2288 	db_print_indent(indent);
2289 	db_printf("t_rttime: %u   t_rtsq: 0x%08x\n",
2290 	    tp->t_rtttime, tp->t_rtseq);
2291 
2292 	db_print_indent(indent);
2293 	db_printf("t_rxtcur: %d   t_maxseg: %u   t_srtt: %d\n",
2294 	    tp->t_rxtcur, tp->t_maxseg, tp->t_srtt);
2295 
2296 	db_print_indent(indent);
2297 	db_printf("t_rttvar: %d   t_rxtshift: %d   t_rttmin: %u   "
2298 	    "t_rttbest: %u\n", tp->t_rttvar, tp->t_rxtshift, tp->t_rttmin,
2299 	    tp->t_rttbest);
2300 
2301 	db_print_indent(indent);
2302 	db_printf("t_rttupdated: %lu   max_sndwnd: %u   t_softerror: %d\n",
2303 	    tp->t_rttupdated, tp->max_sndwnd, tp->t_softerror);
2304 
2305 	db_print_indent(indent);
2306 	db_printf("t_oobflags: 0x%x (", tp->t_oobflags);
2307 	db_print_toobflags(tp->t_oobflags);
2308 	db_printf(")   t_iobc: 0x%02x\n", tp->t_iobc);
2309 
2310 	db_print_indent(indent);
2311 	db_printf("snd_scale: %u   rcv_scale: %u   request_r_scale: %u\n",
2312 	    tp->snd_scale, tp->rcv_scale, tp->request_r_scale);
2313 
2314 	db_print_indent(indent);
2315 	db_printf("ts_recent: %u   ts_recent_age: %u\n",
2316 	    tp->ts_recent, tp->ts_recent_age);
2317 
2318 	db_print_indent(indent);
2319 	db_printf("ts_offset: %u   last_ack_sent: 0x%08x   snd_cwnd_prev: "
2320 	    "%u\n", tp->ts_offset, tp->last_ack_sent, tp->snd_cwnd_prev);
2321 
2322 	db_print_indent(indent);
2323 	db_printf("snd_ssthresh_prev: %u   snd_recover_prev: 0x%08x   "
2324 	    "t_badrxtwin: %u\n", tp->snd_ssthresh_prev,
2325 	    tp->snd_recover_prev, tp->t_badrxtwin);
2326 
2327 	db_print_indent(indent);
2328 	db_printf("snd_numholes: %d  snd_holes first: %p\n",
2329 	    tp->snd_numholes, TAILQ_FIRST(&tp->snd_holes));
2330 
2331 	db_print_indent(indent);
2332 	db_printf("snd_fack: 0x%08x   rcv_numsacks: %d   sack_newdata: "
2333 	    "0x%08x\n", tp->snd_fack, tp->rcv_numsacks, tp->sack_newdata);
2334 
2335 	/* Skip sackblks, sackhint. */
2336 
2337 	db_print_indent(indent);
2338 	db_printf("t_rttlow: %d   rfbuf_ts: %u   rfbuf_cnt: %d\n",
2339 	    tp->t_rttlow, tp->rfbuf_ts, tp->rfbuf_cnt);
2340 }
2341 
2342 DB_SHOW_COMMAND(tcpcb, db_show_tcpcb)
2343 {
2344 	struct tcpcb *tp;
2345 
2346 	if (!have_addr) {
2347 		db_printf("usage: show tcpcb <addr>\n");
2348 		return;
2349 	}
2350 	tp = (struct tcpcb *)addr;
2351 
2352 	db_print_tcpcb(tp, "tcpcb", 0);
2353 }
2354 #endif
2355