xref: /freebsd/sys/netinet/tcp_usrreq.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
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/in.h>
73 #include <netinet/in_kdtrace.h>
74 #include <netinet/in_pcb.h>
75 #include <netinet/in_systm.h>
76 #include <netinet/in_var.h>
77 #include <netinet/ip_var.h>
78 #ifdef INET6
79 #include <netinet/ip6.h>
80 #include <netinet6/in6_pcb.h>
81 #include <netinet6/ip6_var.h>
82 #include <netinet6/scope6_var.h>
83 #endif
84 #ifdef TCP_RFC7413
85 #include <netinet/tcp_fastopen.h>
86 #endif
87 #include <netinet/tcp.h>
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 #include <netinet/cc/cc.h>
94 #ifdef TCPPCAP
95 #include <netinet/tcp_pcap.h>
96 #endif
97 #ifdef TCPDEBUG
98 #include <netinet/tcp_debug.h>
99 #endif
100 #ifdef TCP_OFFLOAD
101 #include <netinet/tcp_offload.h>
102 #endif
103 
104 /*
105  * TCP protocol interface to socket abstraction.
106  */
107 static int	tcp_attach(struct socket *);
108 #ifdef INET
109 static int	tcp_connect(struct tcpcb *, struct sockaddr *,
110 		    struct thread *td);
111 #endif /* INET */
112 #ifdef INET6
113 static int	tcp6_connect(struct tcpcb *, struct sockaddr *,
114 		    struct thread *td);
115 #endif /* INET6 */
116 static void	tcp_disconnect(struct tcpcb *);
117 static void	tcp_usrclosed(struct tcpcb *);
118 static void	tcp_fill_info(struct tcpcb *, struct tcp_info *);
119 
120 #ifdef TCPDEBUG
121 #define	TCPDEBUG0	int ostate = 0
122 #define	TCPDEBUG1()	ostate = tp ? tp->t_state : 0
123 #define	TCPDEBUG2(req)	if (tp && (so->so_options & SO_DEBUG)) \
124 				tcp_trace(TA_USER, ostate, tp, 0, 0, req)
125 #else
126 #define	TCPDEBUG0
127 #define	TCPDEBUG1()
128 #define	TCPDEBUG2(req)
129 #endif
130 
131 /*
132  * TCP attaches to socket via pru_attach(), reserving space,
133  * and an internet control block.
134  */
135 static int
136 tcp_usr_attach(struct socket *so, int proto, struct thread *td)
137 {
138 	struct inpcb *inp;
139 	struct tcpcb *tp = NULL;
140 	int error;
141 	TCPDEBUG0;
142 
143 	inp = sotoinpcb(so);
144 	KASSERT(inp == NULL, ("tcp_usr_attach: inp != NULL"));
145 	TCPDEBUG1();
146 
147 	error = tcp_attach(so);
148 	if (error)
149 		goto out;
150 
151 	if ((so->so_options & SO_LINGER) && so->so_linger == 0)
152 		so->so_linger = TCP_LINGERTIME;
153 
154 	inp = sotoinpcb(so);
155 	tp = intotcpcb(inp);
156 out:
157 	TCPDEBUG2(PRU_ATTACH);
158 	TCP_PROBE2(debug__user, tp, PRU_ATTACH);
159 	return error;
160 }
161 
162 /*
163  * tcp_detach is called when the socket layer loses its final reference
164  * to the socket, be it a file descriptor reference, a reference from TCP,
165  * etc.  At this point, there is only one case in which we will keep around
166  * inpcb state: time wait.
167  *
168  * This function can probably be re-absorbed back into tcp_usr_detach() now
169  * that there is a single detach path.
170  */
171 static void
172 tcp_detach(struct socket *so, struct inpcb *inp)
173 {
174 	struct tcpcb *tp;
175 
176 	INP_INFO_LOCK_ASSERT(&V_tcbinfo);
177 	INP_WLOCK_ASSERT(inp);
178 
179 	KASSERT(so->so_pcb == inp, ("tcp_detach: so_pcb != inp"));
180 	KASSERT(inp->inp_socket == so, ("tcp_detach: inp_socket != so"));
181 
182 	tp = intotcpcb(inp);
183 
184 	if (inp->inp_flags & INP_TIMEWAIT) {
185 		/*
186 		 * There are two cases to handle: one in which the time wait
187 		 * state is being discarded (INP_DROPPED), and one in which
188 		 * this connection will remain in timewait.  In the former,
189 		 * it is time to discard all state (except tcptw, which has
190 		 * already been discarded by the timewait close code, which
191 		 * should be further up the call stack somewhere).  In the
192 		 * latter case, we detach from the socket, but leave the pcb
193 		 * present until timewait ends.
194 		 *
195 		 * XXXRW: Would it be cleaner to free the tcptw here?
196 		 *
197 		 * Astute question indeed, from twtcp perspective there are
198 		 * three cases to consider:
199 		 *
200 		 * #1 tcp_detach is called at tcptw creation time by
201 		 *  tcp_twstart, then do not discard the newly created tcptw
202 		 *  and leave inpcb present until timewait ends
203 		 * #2 tcp_detach is called at timewait end (or reuse) by
204 		 *  tcp_twclose, then the tcptw has already been discarded
205 		 *  (or reused) and inpcb is freed here
206 		 * #3 tcp_detach is called() after timewait ends (or reuse)
207 		 *  (e.g. by soclose), then tcptw has already been discarded
208 		 *  (or reused) and inpcb is freed here
209 		 *
210 		 *  In all three cases the tcptw should not be freed here.
211 		 */
212 		if (inp->inp_flags & INP_DROPPED) {
213 			KASSERT(tp == NULL, ("tcp_detach: INP_TIMEWAIT && "
214 			    "INP_DROPPED && tp != NULL"));
215 			in_pcbdetach(inp);
216 			in_pcbfree(inp);
217 		} else {
218 			in_pcbdetach(inp);
219 			INP_WUNLOCK(inp);
220 		}
221 	} else {
222 		/*
223 		 * If the connection is not in timewait, we consider two
224 		 * two conditions: one in which no further processing is
225 		 * necessary (dropped || embryonic), and one in which TCP is
226 		 * not yet done, but no longer requires the socket, so the
227 		 * pcb will persist for the time being.
228 		 *
229 		 * XXXRW: Does the second case still occur?
230 		 */
231 		if (inp->inp_flags & INP_DROPPED ||
232 		    tp->t_state < TCPS_SYN_SENT) {
233 			tcp_discardcb(tp);
234 			in_pcbdetach(inp);
235 			in_pcbfree(inp);
236 		} else {
237 			in_pcbdetach(inp);
238 			INP_WUNLOCK(inp);
239 		}
240 	}
241 }
242 
243 /*
244  * pru_detach() detaches the TCP protocol from the socket.
245  * If the protocol state is non-embryonic, then can't
246  * do this directly: have to initiate a pru_disconnect(),
247  * which may finish later; embryonic TCB's can just
248  * be discarded here.
249  */
250 static void
251 tcp_usr_detach(struct socket *so)
252 {
253 	struct inpcb *inp;
254 	int rlock = 0;
255 
256 	inp = sotoinpcb(so);
257 	KASSERT(inp != NULL, ("tcp_usr_detach: inp == NULL"));
258 	if (!INP_INFO_WLOCKED(&V_tcbinfo)) {
259 		INP_INFO_RLOCK(&V_tcbinfo);
260 		rlock = 1;
261 	}
262 	INP_WLOCK(inp);
263 	KASSERT(inp->inp_socket != NULL,
264 	    ("tcp_usr_detach: inp_socket == NULL"));
265 	tcp_detach(so, inp);
266 	if (rlock)
267 		INP_INFO_RUNLOCK(&V_tcbinfo);
268 }
269 
270 #ifdef INET
271 /*
272  * Give the socket an address.
273  */
274 static int
275 tcp_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
276 {
277 	int error = 0;
278 	struct inpcb *inp;
279 	struct tcpcb *tp = NULL;
280 	struct sockaddr_in *sinp;
281 
282 	sinp = (struct sockaddr_in *)nam;
283 	if (nam->sa_len != sizeof (*sinp))
284 		return (EINVAL);
285 	/*
286 	 * Must check for multicast addresses and disallow binding
287 	 * to them.
288 	 */
289 	if (sinp->sin_family == AF_INET &&
290 	    IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
291 		return (EAFNOSUPPORT);
292 
293 	TCPDEBUG0;
294 	inp = sotoinpcb(so);
295 	KASSERT(inp != NULL, ("tcp_usr_bind: inp == NULL"));
296 	INP_WLOCK(inp);
297 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
298 		error = EINVAL;
299 		goto out;
300 	}
301 	tp = intotcpcb(inp);
302 	TCPDEBUG1();
303 	INP_HASH_WLOCK(&V_tcbinfo);
304 	error = in_pcbbind(inp, nam, td->td_ucred);
305 	INP_HASH_WUNLOCK(&V_tcbinfo);
306 out:
307 	TCPDEBUG2(PRU_BIND);
308 	TCP_PROBE2(debug__user, tp, PRU_BIND);
309 	INP_WUNLOCK(inp);
310 
311 	return (error);
312 }
313 #endif /* INET */
314 
315 #ifdef INET6
316 static int
317 tcp6_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
318 {
319 	int error = 0;
320 	struct inpcb *inp;
321 	struct tcpcb *tp = NULL;
322 	struct sockaddr_in6 *sin6p;
323 
324 	sin6p = (struct sockaddr_in6 *)nam;
325 	if (nam->sa_len != sizeof (*sin6p))
326 		return (EINVAL);
327 	/*
328 	 * Must check for multicast addresses and disallow binding
329 	 * to them.
330 	 */
331 	if (sin6p->sin6_family == AF_INET6 &&
332 	    IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
333 		return (EAFNOSUPPORT);
334 
335 	TCPDEBUG0;
336 	inp = sotoinpcb(so);
337 	KASSERT(inp != NULL, ("tcp6_usr_bind: inp == NULL"));
338 	INP_WLOCK(inp);
339 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
340 		error = EINVAL;
341 		goto out;
342 	}
343 	tp = intotcpcb(inp);
344 	TCPDEBUG1();
345 	INP_HASH_WLOCK(&V_tcbinfo);
346 	inp->inp_vflag &= ~INP_IPV4;
347 	inp->inp_vflag |= INP_IPV6;
348 #ifdef INET
349 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
350 		if (IN6_IS_ADDR_UNSPECIFIED(&sin6p->sin6_addr))
351 			inp->inp_vflag |= INP_IPV4;
352 		else if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
353 			struct sockaddr_in sin;
354 
355 			in6_sin6_2_sin(&sin, sin6p);
356 			inp->inp_vflag |= INP_IPV4;
357 			inp->inp_vflag &= ~INP_IPV6;
358 			error = in_pcbbind(inp, (struct sockaddr *)&sin,
359 			    td->td_ucred);
360 			INP_HASH_WUNLOCK(&V_tcbinfo);
361 			goto out;
362 		}
363 	}
364 #endif
365 	error = in6_pcbbind(inp, nam, td->td_ucred);
366 	INP_HASH_WUNLOCK(&V_tcbinfo);
367 out:
368 	TCPDEBUG2(PRU_BIND);
369 	TCP_PROBE2(debug__user, tp, PRU_BIND);
370 	INP_WUNLOCK(inp);
371 	return (error);
372 }
373 #endif /* INET6 */
374 
375 #ifdef INET
376 /*
377  * Prepare to accept connections.
378  */
379 static int
380 tcp_usr_listen(struct socket *so, int backlog, struct thread *td)
381 {
382 	int error = 0;
383 	struct inpcb *inp;
384 	struct tcpcb *tp = NULL;
385 
386 	TCPDEBUG0;
387 	inp = sotoinpcb(so);
388 	KASSERT(inp != NULL, ("tcp_usr_listen: inp == NULL"));
389 	INP_WLOCK(inp);
390 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
391 		error = EINVAL;
392 		goto out;
393 	}
394 	tp = intotcpcb(inp);
395 	TCPDEBUG1();
396 	SOCK_LOCK(so);
397 	error = solisten_proto_check(so);
398 	INP_HASH_WLOCK(&V_tcbinfo);
399 	if (error == 0 && inp->inp_lport == 0)
400 		error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
401 	INP_HASH_WUNLOCK(&V_tcbinfo);
402 	if (error == 0) {
403 		tcp_state_change(tp, TCPS_LISTEN);
404 		solisten_proto(so, backlog);
405 #ifdef TCP_OFFLOAD
406 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
407 			tcp_offload_listen_start(tp);
408 #endif
409 	}
410 	SOCK_UNLOCK(so);
411 
412 #ifdef TCP_RFC7413
413 	if (tp->t_flags & TF_FASTOPEN)
414 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
415 #endif
416 out:
417 	TCPDEBUG2(PRU_LISTEN);
418 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
419 	INP_WUNLOCK(inp);
420 	return (error);
421 }
422 #endif /* INET */
423 
424 #ifdef INET6
425 static int
426 tcp6_usr_listen(struct socket *so, int backlog, struct thread *td)
427 {
428 	int error = 0;
429 	struct inpcb *inp;
430 	struct tcpcb *tp = NULL;
431 
432 	TCPDEBUG0;
433 	inp = sotoinpcb(so);
434 	KASSERT(inp != NULL, ("tcp6_usr_listen: inp == NULL"));
435 	INP_WLOCK(inp);
436 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
437 		error = EINVAL;
438 		goto out;
439 	}
440 	tp = intotcpcb(inp);
441 	TCPDEBUG1();
442 	SOCK_LOCK(so);
443 	error = solisten_proto_check(so);
444 	INP_HASH_WLOCK(&V_tcbinfo);
445 	if (error == 0 && inp->inp_lport == 0) {
446 		inp->inp_vflag &= ~INP_IPV4;
447 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
448 			inp->inp_vflag |= INP_IPV4;
449 		error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
450 	}
451 	INP_HASH_WUNLOCK(&V_tcbinfo);
452 	if (error == 0) {
453 		tcp_state_change(tp, TCPS_LISTEN);
454 		solisten_proto(so, backlog);
455 #ifdef TCP_OFFLOAD
456 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
457 			tcp_offload_listen_start(tp);
458 #endif
459 	}
460 	SOCK_UNLOCK(so);
461 
462 #ifdef TCP_RFC7413
463 	if (tp->t_flags & TF_FASTOPEN)
464 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
465 #endif
466 out:
467 	TCPDEBUG2(PRU_LISTEN);
468 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
469 	INP_WUNLOCK(inp);
470 	return (error);
471 }
472 #endif /* INET6 */
473 
474 #ifdef INET
475 /*
476  * Initiate connection to peer.
477  * Create a template for use in transmissions on this connection.
478  * Enter SYN_SENT state, and mark socket as connecting.
479  * Start keep-alive timer, and seed output sequence space.
480  * Send initial segment on connection.
481  */
482 static int
483 tcp_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
484 {
485 	int error = 0;
486 	struct inpcb *inp;
487 	struct tcpcb *tp = NULL;
488 	struct sockaddr_in *sinp;
489 
490 	sinp = (struct sockaddr_in *)nam;
491 	if (nam->sa_len != sizeof (*sinp))
492 		return (EINVAL);
493 	/*
494 	 * Must disallow TCP ``connections'' to multicast addresses.
495 	 */
496 	if (sinp->sin_family == AF_INET
497 	    && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
498 		return (EAFNOSUPPORT);
499 	if ((error = prison_remote_ip4(td->td_ucred, &sinp->sin_addr)) != 0)
500 		return (error);
501 
502 	TCPDEBUG0;
503 	inp = sotoinpcb(so);
504 	KASSERT(inp != NULL, ("tcp_usr_connect: inp == NULL"));
505 	INP_WLOCK(inp);
506 	if (inp->inp_flags & INP_TIMEWAIT) {
507 		error = EADDRINUSE;
508 		goto out;
509 	}
510 	if (inp->inp_flags & INP_DROPPED) {
511 		error = ECONNREFUSED;
512 		goto out;
513 	}
514 	tp = intotcpcb(inp);
515 	TCPDEBUG1();
516 	if ((error = tcp_connect(tp, nam, td)) != 0)
517 		goto out;
518 #ifdef TCP_OFFLOAD
519 	if (registered_toedevs > 0 &&
520 	    (so->so_options & SO_NO_OFFLOAD) == 0 &&
521 	    (error = tcp_offload_connect(so, nam)) == 0)
522 		goto out;
523 #endif
524 	tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
525 	error = tp->t_fb->tfb_tcp_output(tp);
526 out:
527 	TCPDEBUG2(PRU_CONNECT);
528 	INP_WUNLOCK(inp);
529 	return (error);
530 }
531 #endif /* INET */
532 
533 #ifdef INET6
534 static int
535 tcp6_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
536 {
537 	int error = 0;
538 	struct inpcb *inp;
539 	struct tcpcb *tp = NULL;
540 	struct sockaddr_in6 *sin6p;
541 
542 	TCPDEBUG0;
543 
544 	sin6p = (struct sockaddr_in6 *)nam;
545 	if (nam->sa_len != sizeof (*sin6p))
546 		return (EINVAL);
547 	/*
548 	 * Must disallow TCP ``connections'' to multicast addresses.
549 	 */
550 	if (sin6p->sin6_family == AF_INET6
551 	    && IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
552 		return (EAFNOSUPPORT);
553 
554 	inp = sotoinpcb(so);
555 	KASSERT(inp != NULL, ("tcp6_usr_connect: inp == NULL"));
556 	INP_WLOCK(inp);
557 	if (inp->inp_flags & INP_TIMEWAIT) {
558 		error = EADDRINUSE;
559 		goto out;
560 	}
561 	if (inp->inp_flags & INP_DROPPED) {
562 		error = ECONNREFUSED;
563 		goto out;
564 	}
565 	tp = intotcpcb(inp);
566 	TCPDEBUG1();
567 #ifdef INET
568 	/*
569 	 * XXXRW: Some confusion: V4/V6 flags relate to binding, and
570 	 * therefore probably require the hash lock, which isn't held here.
571 	 * Is this a significant problem?
572 	 */
573 	if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
574 		struct sockaddr_in sin;
575 
576 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
577 			error = EINVAL;
578 			goto out;
579 		}
580 
581 		in6_sin6_2_sin(&sin, sin6p);
582 		inp->inp_vflag |= INP_IPV4;
583 		inp->inp_vflag &= ~INP_IPV6;
584 		if ((error = prison_remote_ip4(td->td_ucred,
585 		    &sin.sin_addr)) != 0)
586 			goto out;
587 		if ((error = tcp_connect(tp, (struct sockaddr *)&sin, td)) != 0)
588 			goto out;
589 #ifdef TCP_OFFLOAD
590 		if (registered_toedevs > 0 &&
591 		    (so->so_options & SO_NO_OFFLOAD) == 0 &&
592 		    (error = tcp_offload_connect(so, nam)) == 0)
593 			goto out;
594 #endif
595 		error = tp->t_fb->tfb_tcp_output(tp);
596 		goto out;
597 	}
598 #endif
599 	inp->inp_vflag &= ~INP_IPV4;
600 	inp->inp_vflag |= INP_IPV6;
601 	inp->inp_inc.inc_flags |= INC_ISIPV6;
602 	if ((error = prison_remote_ip6(td->td_ucred, &sin6p->sin6_addr)) != 0)
603 		goto out;
604 	if ((error = tcp6_connect(tp, nam, td)) != 0)
605 		goto out;
606 #ifdef TCP_OFFLOAD
607 	if (registered_toedevs > 0 &&
608 	    (so->so_options & SO_NO_OFFLOAD) == 0 &&
609 	    (error = tcp_offload_connect(so, nam)) == 0)
610 		goto out;
611 #endif
612 	tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
613 	error = tp->t_fb->tfb_tcp_output(tp);
614 
615 out:
616 	TCPDEBUG2(PRU_CONNECT);
617 	TCP_PROBE2(debug__user, tp, PRU_CONNECT);
618 	INP_WUNLOCK(inp);
619 	return (error);
620 }
621 #endif /* INET6 */
622 
623 /*
624  * Initiate disconnect from peer.
625  * If connection never passed embryonic stage, just drop;
626  * else if don't need to let data drain, then can just drop anyways,
627  * else have to begin TCP shutdown process: mark socket disconnecting,
628  * drain unread data, state switch to reflect user close, and
629  * send segment (e.g. FIN) to peer.  Socket will be really disconnected
630  * when peer sends FIN and acks ours.
631  *
632  * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
633  */
634 static int
635 tcp_usr_disconnect(struct socket *so)
636 {
637 	struct inpcb *inp;
638 	struct tcpcb *tp = NULL;
639 	int error = 0;
640 
641 	TCPDEBUG0;
642 	INP_INFO_RLOCK(&V_tcbinfo);
643 	inp = sotoinpcb(so);
644 	KASSERT(inp != NULL, ("tcp_usr_disconnect: inp == NULL"));
645 	INP_WLOCK(inp);
646 	if (inp->inp_flags & INP_TIMEWAIT)
647 		goto out;
648 	if (inp->inp_flags & INP_DROPPED) {
649 		error = ECONNRESET;
650 		goto out;
651 	}
652 	tp = intotcpcb(inp);
653 	TCPDEBUG1();
654 	tcp_disconnect(tp);
655 out:
656 	TCPDEBUG2(PRU_DISCONNECT);
657 	TCP_PROBE2(debug__user, tp, PRU_DISCONNECT);
658 	INP_WUNLOCK(inp);
659 	INP_INFO_RUNLOCK(&V_tcbinfo);
660 	return (error);
661 }
662 
663 #ifdef INET
664 /*
665  * Accept a connection.  Essentially all the work is done at higher levels;
666  * just return the address of the peer, storing through addr.
667  */
668 static int
669 tcp_usr_accept(struct socket *so, struct sockaddr **nam)
670 {
671 	int error = 0;
672 	struct inpcb *inp = NULL;
673 	struct tcpcb *tp = NULL;
674 	struct in_addr addr;
675 	in_port_t port = 0;
676 	TCPDEBUG0;
677 
678 	if (so->so_state & SS_ISDISCONNECTED)
679 		return (ECONNABORTED);
680 
681 	inp = sotoinpcb(so);
682 	KASSERT(inp != NULL, ("tcp_usr_accept: inp == NULL"));
683 	INP_WLOCK(inp);
684 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
685 		error = ECONNABORTED;
686 		goto out;
687 	}
688 	tp = intotcpcb(inp);
689 	TCPDEBUG1();
690 
691 	/*
692 	 * We inline in_getpeeraddr and COMMON_END here, so that we can
693 	 * copy the data of interest and defer the malloc until after we
694 	 * release the lock.
695 	 */
696 	port = inp->inp_fport;
697 	addr = inp->inp_faddr;
698 
699 out:
700 	TCPDEBUG2(PRU_ACCEPT);
701 	TCP_PROBE2(debug__user, tp, PRU_ACCEPT);
702 	INP_WUNLOCK(inp);
703 	if (error == 0)
704 		*nam = in_sockaddr(port, &addr);
705 	return error;
706 }
707 #endif /* INET */
708 
709 #ifdef INET6
710 static int
711 tcp6_usr_accept(struct socket *so, struct sockaddr **nam)
712 {
713 	struct inpcb *inp = NULL;
714 	int error = 0;
715 	struct tcpcb *tp = NULL;
716 	struct in_addr addr;
717 	struct in6_addr addr6;
718 	in_port_t port = 0;
719 	int v4 = 0;
720 	TCPDEBUG0;
721 
722 	if (so->so_state & SS_ISDISCONNECTED)
723 		return (ECONNABORTED);
724 
725 	inp = sotoinpcb(so);
726 	KASSERT(inp != NULL, ("tcp6_usr_accept: inp == NULL"));
727 	INP_INFO_RLOCK(&V_tcbinfo);
728 	INP_WLOCK(inp);
729 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
730 		error = ECONNABORTED;
731 		goto out;
732 	}
733 	tp = intotcpcb(inp);
734 	TCPDEBUG1();
735 
736 	/*
737 	 * We inline in6_mapped_peeraddr and COMMON_END here, so that we can
738 	 * copy the data of interest and defer the malloc until after we
739 	 * release the lock.
740 	 */
741 	if (inp->inp_vflag & INP_IPV4) {
742 		v4 = 1;
743 		port = inp->inp_fport;
744 		addr = inp->inp_faddr;
745 	} else {
746 		port = inp->inp_fport;
747 		addr6 = inp->in6p_faddr;
748 	}
749 
750 out:
751 	TCPDEBUG2(PRU_ACCEPT);
752 	TCP_PROBE2(debug__user, tp, PRU_ACCEPT);
753 	INP_WUNLOCK(inp);
754 	INP_INFO_RUNLOCK(&V_tcbinfo);
755 	if (error == 0) {
756 		if (v4)
757 			*nam = in6_v4mapsin6_sockaddr(port, &addr);
758 		else
759 			*nam = in6_sockaddr(port, &addr6);
760 	}
761 	return error;
762 }
763 #endif /* INET6 */
764 
765 /*
766  * Mark the connection as being incapable of further output.
767  */
768 static int
769 tcp_usr_shutdown(struct socket *so)
770 {
771 	int error = 0;
772 	struct inpcb *inp;
773 	struct tcpcb *tp = NULL;
774 
775 	TCPDEBUG0;
776 	INP_INFO_RLOCK(&V_tcbinfo);
777 	inp = sotoinpcb(so);
778 	KASSERT(inp != NULL, ("inp == NULL"));
779 	INP_WLOCK(inp);
780 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
781 		error = ECONNRESET;
782 		goto out;
783 	}
784 	tp = intotcpcb(inp);
785 	TCPDEBUG1();
786 	socantsendmore(so);
787 	tcp_usrclosed(tp);
788 	if (!(inp->inp_flags & INP_DROPPED))
789 		error = tp->t_fb->tfb_tcp_output(tp);
790 
791 out:
792 	TCPDEBUG2(PRU_SHUTDOWN);
793 	TCP_PROBE2(debug__user, tp, PRU_SHUTDOWN);
794 	INP_WUNLOCK(inp);
795 	INP_INFO_RUNLOCK(&V_tcbinfo);
796 
797 	return (error);
798 }
799 
800 /*
801  * After a receive, possibly send window update to peer.
802  */
803 static int
804 tcp_usr_rcvd(struct socket *so, int flags)
805 {
806 	struct inpcb *inp;
807 	struct tcpcb *tp = NULL;
808 	int error = 0;
809 
810 	TCPDEBUG0;
811 	inp = sotoinpcb(so);
812 	KASSERT(inp != NULL, ("tcp_usr_rcvd: inp == NULL"));
813 	INP_WLOCK(inp);
814 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
815 		error = ECONNRESET;
816 		goto out;
817 	}
818 	tp = intotcpcb(inp);
819 	TCPDEBUG1();
820 #ifdef TCP_RFC7413
821 	/*
822 	 * For passively-created TFO connections, don't attempt a window
823 	 * update while still in SYN_RECEIVED as this may trigger an early
824 	 * SYN|ACK.  It is preferable to have the SYN|ACK be sent along with
825 	 * application response data, or failing that, when the DELACK timer
826 	 * expires.
827 	 */
828 	if ((tp->t_flags & TF_FASTOPEN) &&
829 	    (tp->t_state == TCPS_SYN_RECEIVED))
830 		goto out;
831 #endif
832 #ifdef TCP_OFFLOAD
833 	if (tp->t_flags & TF_TOE)
834 		tcp_offload_rcvd(tp);
835 	else
836 #endif
837 	tp->t_fb->tfb_tcp_output(tp);
838 
839 out:
840 	TCPDEBUG2(PRU_RCVD);
841 	TCP_PROBE2(debug__user, tp, PRU_RCVD);
842 	INP_WUNLOCK(inp);
843 	return (error);
844 }
845 
846 /*
847  * Do a send by putting data in output queue and updating urgent
848  * marker if URG set.  Possibly send more data.  Unlike the other
849  * pru_*() routines, the mbuf chains are our responsibility.  We
850  * must either enqueue them or free them.  The other pru_* routines
851  * generally are caller-frees.
852  */
853 static int
854 tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
855     struct sockaddr *nam, struct mbuf *control, struct thread *td)
856 {
857 	int error = 0;
858 	struct inpcb *inp;
859 	struct tcpcb *tp = NULL;
860 #ifdef INET6
861 	int isipv6;
862 #endif
863 	TCPDEBUG0;
864 
865 	/*
866 	 * We require the pcbinfo lock if we will close the socket as part of
867 	 * this call.
868 	 */
869 	if (flags & PRUS_EOF)
870 		INP_INFO_RLOCK(&V_tcbinfo);
871 	inp = sotoinpcb(so);
872 	KASSERT(inp != NULL, ("tcp_usr_send: inp == NULL"));
873 	INP_WLOCK(inp);
874 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
875 		if (control)
876 			m_freem(control);
877 		/*
878 		 * In case of PRUS_NOTREADY, tcp_usr_ready() is responsible
879 		 * for freeing memory.
880 		 */
881 		if (m && (flags & PRUS_NOTREADY) == 0)
882 			m_freem(m);
883 		error = ECONNRESET;
884 		goto out;
885 	}
886 #ifdef INET6
887 	isipv6 = nam && nam->sa_family == AF_INET6;
888 #endif /* INET6 */
889 	tp = intotcpcb(inp);
890 	TCPDEBUG1();
891 	if (control) {
892 		/* TCP doesn't do control messages (rights, creds, etc) */
893 		if (control->m_len) {
894 			m_freem(control);
895 			if (m)
896 				m_freem(m);
897 			error = EINVAL;
898 			goto out;
899 		}
900 		m_freem(control);	/* empty control, just free it */
901 	}
902 	if (!(flags & PRUS_OOB)) {
903 		sbappendstream(&so->so_snd, m, flags);
904 		if (nam && tp->t_state < TCPS_SYN_SENT) {
905 			/*
906 			 * Do implied connect if not yet connected,
907 			 * initialize window to default value, and
908 			 * initialize maxseg using peer's cached 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 using peer's cached MSS.
968 			 */
969 #ifdef INET6
970 			if (isipv6)
971 				error = tcp6_connect(tp, nam, td);
972 #endif /* INET6 */
973 #if defined(INET6) && defined(INET)
974 			else
975 #endif
976 #ifdef INET
977 				error = tcp_connect(tp, nam, td);
978 #endif
979 			if (error)
980 				goto out;
981 			tp->snd_wnd = TTCP_CLIENT_SND_WND;
982 			tcp_mss(tp, -1);
983 		}
984 		tp->snd_up = tp->snd_una + sbavail(&so->so_snd);
985 		if (!(flags & PRUS_NOTREADY)) {
986 			tp->t_flags |= TF_FORCEDATA;
987 			error = tp->t_fb->tfb_tcp_output(tp);
988 			tp->t_flags &= ~TF_FORCEDATA;
989 		}
990 	}
991 out:
992 	TCPDEBUG2((flags & PRUS_OOB) ? PRU_SENDOOB :
993 		  ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
994 	TCP_PROBE2(debug__user, tp, (flags & PRUS_OOB) ? PRU_SENDOOB :
995 		   ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
996 	INP_WUNLOCK(inp);
997 	if (flags & PRUS_EOF)
998 		INP_INFO_RUNLOCK(&V_tcbinfo);
999 	return (error);
1000 }
1001 
1002 static int
1003 tcp_usr_ready(struct socket *so, struct mbuf *m, int count)
1004 {
1005 	struct inpcb *inp;
1006 	struct tcpcb *tp;
1007 	int error;
1008 
1009 	inp = sotoinpcb(so);
1010 	INP_WLOCK(inp);
1011 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1012 		INP_WUNLOCK(inp);
1013 		for (int i = 0; i < count; i++)
1014 			m = m_free(m);
1015 		return (ECONNRESET);
1016 	}
1017 	tp = intotcpcb(inp);
1018 
1019 	SOCKBUF_LOCK(&so->so_snd);
1020 	error = sbready(&so->so_snd, m, count);
1021 	SOCKBUF_UNLOCK(&so->so_snd);
1022 	if (error == 0)
1023 		error = tp->t_fb->tfb_tcp_output(tp);
1024 	INP_WUNLOCK(inp);
1025 
1026 	return (error);
1027 }
1028 
1029 /*
1030  * Abort the TCP.  Drop the connection abruptly.
1031  */
1032 static void
1033 tcp_usr_abort(struct socket *so)
1034 {
1035 	struct inpcb *inp;
1036 	struct tcpcb *tp = NULL;
1037 	TCPDEBUG0;
1038 
1039 	inp = sotoinpcb(so);
1040 	KASSERT(inp != NULL, ("tcp_usr_abort: inp == NULL"));
1041 
1042 	INP_INFO_RLOCK(&V_tcbinfo);
1043 	INP_WLOCK(inp);
1044 	KASSERT(inp->inp_socket != NULL,
1045 	    ("tcp_usr_abort: inp_socket == NULL"));
1046 
1047 	/*
1048 	 * If we still have full TCP state, and we're not dropped, drop.
1049 	 */
1050 	if (!(inp->inp_flags & INP_TIMEWAIT) &&
1051 	    !(inp->inp_flags & INP_DROPPED)) {
1052 		tp = intotcpcb(inp);
1053 		TCPDEBUG1();
1054 		tcp_drop(tp, ECONNABORTED);
1055 		TCPDEBUG2(PRU_ABORT);
1056 		TCP_PROBE2(debug__user, tp, PRU_ABORT);
1057 	}
1058 	if (!(inp->inp_flags & INP_DROPPED)) {
1059 		SOCK_LOCK(so);
1060 		so->so_state |= SS_PROTOREF;
1061 		SOCK_UNLOCK(so);
1062 		inp->inp_flags |= INP_SOCKREF;
1063 	}
1064 	INP_WUNLOCK(inp);
1065 	INP_INFO_RUNLOCK(&V_tcbinfo);
1066 }
1067 
1068 /*
1069  * TCP socket is closed.  Start friendly disconnect.
1070  */
1071 static void
1072 tcp_usr_close(struct socket *so)
1073 {
1074 	struct inpcb *inp;
1075 	struct tcpcb *tp = NULL;
1076 	TCPDEBUG0;
1077 
1078 	inp = sotoinpcb(so);
1079 	KASSERT(inp != NULL, ("tcp_usr_close: inp == NULL"));
1080 
1081 	INP_INFO_RLOCK(&V_tcbinfo);
1082 	INP_WLOCK(inp);
1083 	KASSERT(inp->inp_socket != NULL,
1084 	    ("tcp_usr_close: inp_socket == NULL"));
1085 
1086 	/*
1087 	 * If we still have full TCP state, and we're not dropped, initiate
1088 	 * a disconnect.
1089 	 */
1090 	if (!(inp->inp_flags & INP_TIMEWAIT) &&
1091 	    !(inp->inp_flags & INP_DROPPED)) {
1092 		tp = intotcpcb(inp);
1093 		TCPDEBUG1();
1094 		tcp_disconnect(tp);
1095 		TCPDEBUG2(PRU_CLOSE);
1096 		TCP_PROBE2(debug__user, tp, PRU_CLOSE);
1097 	}
1098 	if (!(inp->inp_flags & INP_DROPPED)) {
1099 		SOCK_LOCK(so);
1100 		so->so_state |= SS_PROTOREF;
1101 		SOCK_UNLOCK(so);
1102 		inp->inp_flags |= INP_SOCKREF;
1103 	}
1104 	INP_WUNLOCK(inp);
1105 	INP_INFO_RUNLOCK(&V_tcbinfo);
1106 }
1107 
1108 /*
1109  * Receive out-of-band data.
1110  */
1111 static int
1112 tcp_usr_rcvoob(struct socket *so, struct mbuf *m, int flags)
1113 {
1114 	int error = 0;
1115 	struct inpcb *inp;
1116 	struct tcpcb *tp = NULL;
1117 
1118 	TCPDEBUG0;
1119 	inp = sotoinpcb(so);
1120 	KASSERT(inp != NULL, ("tcp_usr_rcvoob: inp == NULL"));
1121 	INP_WLOCK(inp);
1122 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1123 		error = ECONNRESET;
1124 		goto out;
1125 	}
1126 	tp = intotcpcb(inp);
1127 	TCPDEBUG1();
1128 	if ((so->so_oobmark == 0 &&
1129 	     (so->so_rcv.sb_state & SBS_RCVATMARK) == 0) ||
1130 	    so->so_options & SO_OOBINLINE ||
1131 	    tp->t_oobflags & TCPOOB_HADDATA) {
1132 		error = EINVAL;
1133 		goto out;
1134 	}
1135 	if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
1136 		error = EWOULDBLOCK;
1137 		goto out;
1138 	}
1139 	m->m_len = 1;
1140 	*mtod(m, caddr_t) = tp->t_iobc;
1141 	if ((flags & MSG_PEEK) == 0)
1142 		tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
1143 
1144 out:
1145 	TCPDEBUG2(PRU_RCVOOB);
1146 	TCP_PROBE2(debug__user, tp, PRU_RCVOOB);
1147 	INP_WUNLOCK(inp);
1148 	return (error);
1149 }
1150 
1151 #ifdef INET
1152 struct pr_usrreqs tcp_usrreqs = {
1153 	.pru_abort =		tcp_usr_abort,
1154 	.pru_accept =		tcp_usr_accept,
1155 	.pru_attach =		tcp_usr_attach,
1156 	.pru_bind =		tcp_usr_bind,
1157 	.pru_connect =		tcp_usr_connect,
1158 	.pru_control =		in_control,
1159 	.pru_detach =		tcp_usr_detach,
1160 	.pru_disconnect =	tcp_usr_disconnect,
1161 	.pru_listen =		tcp_usr_listen,
1162 	.pru_peeraddr =		in_getpeeraddr,
1163 	.pru_rcvd =		tcp_usr_rcvd,
1164 	.pru_rcvoob =		tcp_usr_rcvoob,
1165 	.pru_send =		tcp_usr_send,
1166 	.pru_ready =		tcp_usr_ready,
1167 	.pru_shutdown =		tcp_usr_shutdown,
1168 	.pru_sockaddr =		in_getsockaddr,
1169 	.pru_sosetlabel =	in_pcbsosetlabel,
1170 	.pru_close =		tcp_usr_close,
1171 };
1172 #endif /* INET */
1173 
1174 #ifdef INET6
1175 struct pr_usrreqs tcp6_usrreqs = {
1176 	.pru_abort =		tcp_usr_abort,
1177 	.pru_accept =		tcp6_usr_accept,
1178 	.pru_attach =		tcp_usr_attach,
1179 	.pru_bind =		tcp6_usr_bind,
1180 	.pru_connect =		tcp6_usr_connect,
1181 	.pru_control =		in6_control,
1182 	.pru_detach =		tcp_usr_detach,
1183 	.pru_disconnect =	tcp_usr_disconnect,
1184 	.pru_listen =		tcp6_usr_listen,
1185 	.pru_peeraddr =		in6_mapped_peeraddr,
1186 	.pru_rcvd =		tcp_usr_rcvd,
1187 	.pru_rcvoob =		tcp_usr_rcvoob,
1188 	.pru_send =		tcp_usr_send,
1189 	.pru_ready =		tcp_usr_ready,
1190 	.pru_shutdown =		tcp_usr_shutdown,
1191 	.pru_sockaddr =		in6_mapped_sockaddr,
1192 	.pru_sosetlabel =	in_pcbsosetlabel,
1193 	.pru_close =		tcp_usr_close,
1194 };
1195 #endif /* INET6 */
1196 
1197 #ifdef INET
1198 /*
1199  * Common subroutine to open a TCP connection to remote host specified
1200  * by struct sockaddr_in in mbuf *nam.  Call in_pcbbind to assign a local
1201  * port number if needed.  Call in_pcbconnect_setup to do the routing and
1202  * to choose a local host address (interface).  If there is an existing
1203  * incarnation of the same connection in TIME-WAIT state and if the remote
1204  * host was sending CC options and if the connection duration was < MSL, then
1205  * truncate the previous TIME-WAIT state and proceed.
1206  * Initialize connection parameters and enter SYN-SENT state.
1207  */
1208 static int
1209 tcp_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
1210 {
1211 	struct inpcb *inp = tp->t_inpcb, *oinp;
1212 	struct socket *so = inp->inp_socket;
1213 	struct in_addr laddr;
1214 	u_short lport;
1215 	int error;
1216 
1217 	INP_WLOCK_ASSERT(inp);
1218 	INP_HASH_WLOCK(&V_tcbinfo);
1219 
1220 	if (inp->inp_lport == 0) {
1221 		error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
1222 		if (error)
1223 			goto out;
1224 	}
1225 
1226 	/*
1227 	 * Cannot simply call in_pcbconnect, because there might be an
1228 	 * earlier incarnation of this same connection still in
1229 	 * TIME_WAIT state, creating an ADDRINUSE error.
1230 	 */
1231 	laddr = inp->inp_laddr;
1232 	lport = inp->inp_lport;
1233 	error = in_pcbconnect_setup(inp, nam, &laddr.s_addr, &lport,
1234 	    &inp->inp_faddr.s_addr, &inp->inp_fport, &oinp, td->td_ucred);
1235 	if (error && oinp == NULL)
1236 		goto out;
1237 	if (oinp) {
1238 		error = EADDRINUSE;
1239 		goto out;
1240 	}
1241 	inp->inp_laddr = laddr;
1242 	in_pcbrehash(inp);
1243 	INP_HASH_WUNLOCK(&V_tcbinfo);
1244 
1245 	/*
1246 	 * Compute window scaling to request:
1247 	 * Scale to fit into sweet spot.  See tcp_syncache.c.
1248 	 * XXX: This should move to tcp_output().
1249 	 */
1250 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1251 	    (TCP_MAXWIN << tp->request_r_scale) < sb_max)
1252 		tp->request_r_scale++;
1253 
1254 	soisconnecting(so);
1255 	TCPSTAT_INC(tcps_connattempt);
1256 	tcp_state_change(tp, TCPS_SYN_SENT);
1257 	tp->iss = tcp_new_isn(tp);
1258 	tcp_sendseqinit(tp);
1259 
1260 	return 0;
1261 
1262 out:
1263 	INP_HASH_WUNLOCK(&V_tcbinfo);
1264 	return (error);
1265 }
1266 #endif /* INET */
1267 
1268 #ifdef INET6
1269 static int
1270 tcp6_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
1271 {
1272 	struct inpcb *inp = tp->t_inpcb;
1273 	int error;
1274 
1275 	INP_WLOCK_ASSERT(inp);
1276 	INP_HASH_WLOCK(&V_tcbinfo);
1277 
1278 	if (inp->inp_lport == 0) {
1279 		error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
1280 		if (error)
1281 			goto out;
1282 	}
1283 	error = in6_pcbconnect(inp, nam, td->td_ucred);
1284 	if (error != 0)
1285 		goto out;
1286 	INP_HASH_WUNLOCK(&V_tcbinfo);
1287 
1288 	/* Compute window scaling to request.  */
1289 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1290 	    (TCP_MAXWIN << tp->request_r_scale) < sb_max)
1291 		tp->request_r_scale++;
1292 
1293 	soisconnecting(inp->inp_socket);
1294 	TCPSTAT_INC(tcps_connattempt);
1295 	tcp_state_change(tp, TCPS_SYN_SENT);
1296 	tp->iss = tcp_new_isn(tp);
1297 	tcp_sendseqinit(tp);
1298 
1299 	return 0;
1300 
1301 out:
1302 	INP_HASH_WUNLOCK(&V_tcbinfo);
1303 	return error;
1304 }
1305 #endif /* INET6 */
1306 
1307 /*
1308  * Export TCP internal state information via a struct tcp_info, based on the
1309  * Linux 2.6 API.  Not ABI compatible as our constants are mapped differently
1310  * (TCP state machine, etc).  We export all information using FreeBSD-native
1311  * constants -- for example, the numeric values for tcpi_state will differ
1312  * from Linux.
1313  */
1314 static void
1315 tcp_fill_info(struct tcpcb *tp, struct tcp_info *ti)
1316 {
1317 
1318 	INP_WLOCK_ASSERT(tp->t_inpcb);
1319 	bzero(ti, sizeof(*ti));
1320 
1321 	ti->tcpi_state = tp->t_state;
1322 	if ((tp->t_flags & TF_REQ_TSTMP) && (tp->t_flags & TF_RCVD_TSTMP))
1323 		ti->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1324 	if (tp->t_flags & TF_SACK_PERMIT)
1325 		ti->tcpi_options |= TCPI_OPT_SACK;
1326 	if ((tp->t_flags & TF_REQ_SCALE) && (tp->t_flags & TF_RCVD_SCALE)) {
1327 		ti->tcpi_options |= TCPI_OPT_WSCALE;
1328 		ti->tcpi_snd_wscale = tp->snd_scale;
1329 		ti->tcpi_rcv_wscale = tp->rcv_scale;
1330 	}
1331 
1332 	ti->tcpi_rto = tp->t_rxtcur * tick;
1333 	ti->tcpi_last_data_recv = (long)(ticks - (int)tp->t_rcvtime) * tick;
1334 	ti->tcpi_rtt = ((u_int64_t)tp->t_srtt * tick) >> TCP_RTT_SHIFT;
1335 	ti->tcpi_rttvar = ((u_int64_t)tp->t_rttvar * tick) >> TCP_RTTVAR_SHIFT;
1336 
1337 	ti->tcpi_snd_ssthresh = tp->snd_ssthresh;
1338 	ti->tcpi_snd_cwnd = tp->snd_cwnd;
1339 
1340 	/*
1341 	 * FreeBSD-specific extension fields for tcp_info.
1342 	 */
1343 	ti->tcpi_rcv_space = tp->rcv_wnd;
1344 	ti->tcpi_rcv_nxt = tp->rcv_nxt;
1345 	ti->tcpi_snd_wnd = tp->snd_wnd;
1346 	ti->tcpi_snd_bwnd = 0;		/* Unused, kept for compat. */
1347 	ti->tcpi_snd_nxt = tp->snd_nxt;
1348 	ti->tcpi_snd_mss = tp->t_maxseg;
1349 	ti->tcpi_rcv_mss = tp->t_maxseg;
1350 	if (tp->t_flags & TF_TOE)
1351 		ti->tcpi_options |= TCPI_OPT_TOE;
1352 	ti->tcpi_snd_rexmitpack = tp->t_sndrexmitpack;
1353 	ti->tcpi_rcv_ooopack = tp->t_rcvoopack;
1354 	ti->tcpi_snd_zerowin = tp->t_sndzerowin;
1355 }
1356 
1357 /*
1358  * tcp_ctloutput() must drop the inpcb lock before performing copyin on
1359  * socket option arguments.  When it re-acquires the lock after the copy, it
1360  * has to revalidate that the connection is still valid for the socket
1361  * option.
1362  */
1363 #define INP_WLOCK_RECHECK(inp) do {					\
1364 	INP_WLOCK(inp);							\
1365 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {		\
1366 		INP_WUNLOCK(inp);					\
1367 		return (ECONNRESET);					\
1368 	}								\
1369 	tp = intotcpcb(inp);						\
1370 } while(0)
1371 
1372 int
1373 tcp_ctloutput(struct socket *so, struct sockopt *sopt)
1374 {
1375 	int	error;
1376 	struct	inpcb *inp;
1377 	struct	tcpcb *tp;
1378 	struct tcp_function_block *blk;
1379 	struct tcp_function_set fsn;
1380 
1381 	error = 0;
1382 	inp = sotoinpcb(so);
1383 	KASSERT(inp != NULL, ("tcp_ctloutput: inp == NULL"));
1384 	INP_WLOCK(inp);
1385 	if (sopt->sopt_level != IPPROTO_TCP) {
1386 #ifdef INET6
1387 		if (inp->inp_vflag & INP_IPV6PROTO) {
1388 			INP_WUNLOCK(inp);
1389 			error = ip6_ctloutput(so, sopt);
1390 		}
1391 #endif /* INET6 */
1392 #if defined(INET6) && defined(INET)
1393 		else
1394 #endif
1395 #ifdef INET
1396 		{
1397 			INP_WUNLOCK(inp);
1398 			error = ip_ctloutput(so, sopt);
1399 		}
1400 #endif
1401 		return (error);
1402 	}
1403 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
1404 		INP_WUNLOCK(inp);
1405 		return (ECONNRESET);
1406 	}
1407 	tp = intotcpcb(inp);
1408 	/*
1409 	 * Protect the TCP option TCP_FUNCTION_BLK so
1410 	 * that a sub-function can *never* overwrite this.
1411 	 */
1412 	if ((sopt->sopt_dir == SOPT_SET) &&
1413 	    (sopt->sopt_name == TCP_FUNCTION_BLK)) {
1414 		INP_WUNLOCK(inp);
1415 		error = sooptcopyin(sopt, &fsn, sizeof fsn,
1416 		    sizeof fsn);
1417 		if (error)
1418 			return (error);
1419 		INP_WLOCK_RECHECK(inp);
1420 		if (tp->t_state != TCPS_CLOSED) {
1421 			/*
1422 			 * The user has advanced the state
1423 			 * past the initial point, we can't
1424 			 * switch since we are down the road
1425 			 * and a new set of functions may
1426 			 * not be compatibile.
1427 			 */
1428 			INP_WUNLOCK(inp);
1429 			return(EINVAL);
1430 		}
1431 		blk = find_and_ref_tcp_functions(&fsn);
1432 		if (blk == NULL) {
1433 			INP_WUNLOCK(inp);
1434 			return (ENOENT);
1435 		}
1436 		if (tp->t_fb != blk) {
1437 			if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
1438 				refcount_release(&blk->tfb_refcnt);
1439 				INP_WUNLOCK(inp);
1440 				return (ENOENT);
1441 			}
1442 			/*
1443 			 * Release the old refcnt, the
1444 			 * lookup acquires a ref on the
1445 			 * new one.
1446 			 */
1447 			if (tp->t_fb->tfb_tcp_fb_fini)
1448 				(*tp->t_fb->tfb_tcp_fb_fini)(tp);
1449 			refcount_release(&tp->t_fb->tfb_refcnt);
1450 			tp->t_fb = blk;
1451 			if (tp->t_fb->tfb_tcp_fb_init) {
1452 				(*tp->t_fb->tfb_tcp_fb_init)(tp);
1453 			}
1454 		}
1455 #ifdef TCP_OFFLOAD
1456 		if (tp->t_flags & TF_TOE) {
1457 			tcp_offload_ctloutput(tp, sopt->sopt_dir,
1458 			     sopt->sopt_name);
1459 		}
1460 #endif
1461 		INP_WUNLOCK(inp);
1462 		return (error);
1463 	} else if ((sopt->sopt_dir == SOPT_GET) &&
1464 	    (sopt->sopt_name == TCP_FUNCTION_BLK)) {
1465 		strcpy(fsn.function_set_name, tp->t_fb->tfb_tcp_block_name);
1466 		fsn.pcbcnt = tp->t_fb->tfb_refcnt;
1467 		INP_WUNLOCK(inp);
1468 		error = sooptcopyout(sopt, &fsn, sizeof fsn);
1469 		return (error);
1470 	}
1471 	/* Pass in the INP locked, called must unlock it */
1472 	return (tp->t_fb->tfb_tcp_ctloutput(so, sopt, inp, tp));
1473 }
1474 
1475 int
1476 tcp_default_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp)
1477 {
1478 	int	error, opt, optval;
1479 	u_int	ui;
1480 	struct	tcp_info ti;
1481 	struct cc_algo *algo;
1482 	char	*pbuf, buf[TCP_CA_NAME_MAX];
1483 	size_t	len;
1484 
1485 	/*
1486 	 * For TCP_CCALGOOPT forward the control to CC module, for both
1487 	 * SOPT_SET and SOPT_GET.
1488 	 */
1489 	switch (sopt->sopt_name) {
1490 	case TCP_CCALGOOPT:
1491 		INP_WUNLOCK(inp);
1492 		pbuf = malloc(sopt->sopt_valsize, M_TEMP, M_WAITOK | M_ZERO);
1493 		error = sooptcopyin(sopt, pbuf, sopt->sopt_valsize,
1494 		    sopt->sopt_valsize);
1495 		if (error) {
1496 			free(pbuf, M_TEMP);
1497 			return (error);
1498 		}
1499 		INP_WLOCK_RECHECK(inp);
1500 		if (CC_ALGO(tp)->ctl_output != NULL)
1501 			error = CC_ALGO(tp)->ctl_output(tp->ccv, sopt, pbuf);
1502 		else
1503 			error = ENOENT;
1504 		INP_WUNLOCK(inp);
1505 		if (error == 0 && sopt->sopt_dir == SOPT_GET)
1506 			error = sooptcopyout(sopt, pbuf, sopt->sopt_valsize);
1507 		free(pbuf, M_TEMP);
1508 		return (error);
1509 	}
1510 
1511 	switch (sopt->sopt_dir) {
1512 	case SOPT_SET:
1513 		switch (sopt->sopt_name) {
1514 #ifdef TCP_SIGNATURE
1515 		case TCP_MD5SIG:
1516 			INP_WUNLOCK(inp);
1517 			error = sooptcopyin(sopt, &optval, sizeof optval,
1518 			    sizeof optval);
1519 			if (error)
1520 				return (error);
1521 
1522 			INP_WLOCK_RECHECK(inp);
1523 			if (optval > 0)
1524 				tp->t_flags |= TF_SIGNATURE;
1525 			else
1526 				tp->t_flags &= ~TF_SIGNATURE;
1527 			goto unlock_and_done;
1528 #endif /* TCP_SIGNATURE */
1529 
1530 		case TCP_NODELAY:
1531 		case TCP_NOOPT:
1532 			INP_WUNLOCK(inp);
1533 			error = sooptcopyin(sopt, &optval, sizeof optval,
1534 			    sizeof optval);
1535 			if (error)
1536 				return (error);
1537 
1538 			INP_WLOCK_RECHECK(inp);
1539 			switch (sopt->sopt_name) {
1540 			case TCP_NODELAY:
1541 				opt = TF_NODELAY;
1542 				break;
1543 			case TCP_NOOPT:
1544 				opt = TF_NOOPT;
1545 				break;
1546 			default:
1547 				opt = 0; /* dead code to fool gcc */
1548 				break;
1549 			}
1550 
1551 			if (optval)
1552 				tp->t_flags |= opt;
1553 			else
1554 				tp->t_flags &= ~opt;
1555 unlock_and_done:
1556 #ifdef TCP_OFFLOAD
1557 			if (tp->t_flags & TF_TOE) {
1558 				tcp_offload_ctloutput(tp, sopt->sopt_dir,
1559 				    sopt->sopt_name);
1560 			}
1561 #endif
1562 			INP_WUNLOCK(inp);
1563 			break;
1564 
1565 		case TCP_NOPUSH:
1566 			INP_WUNLOCK(inp);
1567 			error = sooptcopyin(sopt, &optval, sizeof optval,
1568 			    sizeof optval);
1569 			if (error)
1570 				return (error);
1571 
1572 			INP_WLOCK_RECHECK(inp);
1573 			if (optval)
1574 				tp->t_flags |= TF_NOPUSH;
1575 			else if (tp->t_flags & TF_NOPUSH) {
1576 				tp->t_flags &= ~TF_NOPUSH;
1577 				if (TCPS_HAVEESTABLISHED(tp->t_state))
1578 					error = tp->t_fb->tfb_tcp_output(tp);
1579 			}
1580 			goto unlock_and_done;
1581 
1582 		case TCP_MAXSEG:
1583 			INP_WUNLOCK(inp);
1584 			error = sooptcopyin(sopt, &optval, sizeof optval,
1585 			    sizeof optval);
1586 			if (error)
1587 				return (error);
1588 
1589 			INP_WLOCK_RECHECK(inp);
1590 			if (optval > 0 && optval <= tp->t_maxseg &&
1591 			    optval + 40 >= V_tcp_minmss)
1592 				tp->t_maxseg = optval;
1593 			else
1594 				error = EINVAL;
1595 			goto unlock_and_done;
1596 
1597 		case TCP_INFO:
1598 			INP_WUNLOCK(inp);
1599 			error = EINVAL;
1600 			break;
1601 
1602 		case TCP_CONGESTION:
1603 			INP_WUNLOCK(inp);
1604 			error = sooptcopyin(sopt, buf, TCP_CA_NAME_MAX - 1, 1);
1605 			if (error)
1606 				break;
1607 			buf[sopt->sopt_valsize] = '\0';
1608 			INP_WLOCK_RECHECK(inp);
1609 			CC_LIST_RLOCK();
1610 			STAILQ_FOREACH(algo, &cc_list, entries)
1611 				if (strncmp(buf, algo->name,
1612 				    TCP_CA_NAME_MAX) == 0)
1613 					break;
1614 			CC_LIST_RUNLOCK();
1615 			if (algo == NULL) {
1616 				INP_WUNLOCK(inp);
1617 				error = EINVAL;
1618 				break;
1619 			}
1620 			/*
1621 			 * We hold a write lock over the tcb so it's safe to
1622 			 * do these things without ordering concerns.
1623 			 */
1624 			if (CC_ALGO(tp)->cb_destroy != NULL)
1625 				CC_ALGO(tp)->cb_destroy(tp->ccv);
1626 			CC_ALGO(tp) = algo;
1627 			/*
1628 			 * If something goes pear shaped initialising the new
1629 			 * algo, fall back to newreno (which does not
1630 			 * require initialisation).
1631 			 */
1632 			if (algo->cb_init != NULL &&
1633 			    algo->cb_init(tp->ccv) != 0) {
1634 				CC_ALGO(tp) = &newreno_cc_algo;
1635 				/*
1636 				 * The only reason init should fail is
1637 				 * because of malloc.
1638 				 */
1639 				error = ENOMEM;
1640 			}
1641 			INP_WUNLOCK(inp);
1642 			break;
1643 
1644 		case TCP_KEEPIDLE:
1645 		case TCP_KEEPINTVL:
1646 		case TCP_KEEPINIT:
1647 			INP_WUNLOCK(inp);
1648 			error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
1649 			if (error)
1650 				return (error);
1651 
1652 			if (ui > (UINT_MAX / hz)) {
1653 				error = EINVAL;
1654 				break;
1655 			}
1656 			ui *= hz;
1657 
1658 			INP_WLOCK_RECHECK(inp);
1659 			switch (sopt->sopt_name) {
1660 			case TCP_KEEPIDLE:
1661 				tp->t_keepidle = ui;
1662 				/*
1663 				 * XXX: better check current remaining
1664 				 * timeout and "merge" it with new value.
1665 				 */
1666 				if ((tp->t_state > TCPS_LISTEN) &&
1667 				    (tp->t_state <= TCPS_CLOSING))
1668 					tcp_timer_activate(tp, TT_KEEP,
1669 					    TP_KEEPIDLE(tp));
1670 				break;
1671 			case TCP_KEEPINTVL:
1672 				tp->t_keepintvl = ui;
1673 				if ((tp->t_state == TCPS_FIN_WAIT_2) &&
1674 				    (TP_MAXIDLE(tp) > 0))
1675 					tcp_timer_activate(tp, TT_2MSL,
1676 					    TP_MAXIDLE(tp));
1677 				break;
1678 			case TCP_KEEPINIT:
1679 				tp->t_keepinit = ui;
1680 				if (tp->t_state == TCPS_SYN_RECEIVED ||
1681 				    tp->t_state == TCPS_SYN_SENT)
1682 					tcp_timer_activate(tp, TT_KEEP,
1683 					    TP_KEEPINIT(tp));
1684 				break;
1685 			}
1686 			goto unlock_and_done;
1687 
1688 		case TCP_KEEPCNT:
1689 			INP_WUNLOCK(inp);
1690 			error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
1691 			if (error)
1692 				return (error);
1693 
1694 			INP_WLOCK_RECHECK(inp);
1695 			tp->t_keepcnt = ui;
1696 			if ((tp->t_state == TCPS_FIN_WAIT_2) &&
1697 			    (TP_MAXIDLE(tp) > 0))
1698 				tcp_timer_activate(tp, TT_2MSL,
1699 				    TP_MAXIDLE(tp));
1700 			goto unlock_and_done;
1701 
1702 #ifdef TCPPCAP
1703 		case TCP_PCAP_OUT:
1704 		case TCP_PCAP_IN:
1705 			INP_WUNLOCK(inp);
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 >= 0)
1713 				tcp_pcap_set_sock_max(TCP_PCAP_OUT ?
1714 					&(tp->t_outpkts) : &(tp->t_inpkts),
1715 					optval);
1716 			else
1717 				error = EINVAL;
1718 			goto unlock_and_done;
1719 #endif
1720 
1721 #ifdef TCP_RFC7413
1722 		case TCP_FASTOPEN:
1723 			INP_WUNLOCK(inp);
1724 			if (!V_tcp_fastopen_enabled)
1725 				return (EPERM);
1726 
1727 			error = sooptcopyin(sopt, &optval, sizeof optval,
1728 			    sizeof optval);
1729 			if (error)
1730 				return (error);
1731 
1732 			INP_WLOCK_RECHECK(inp);
1733 			if (optval) {
1734 				tp->t_flags |= TF_FASTOPEN;
1735 				if ((tp->t_state == TCPS_LISTEN) &&
1736 				    (tp->t_tfo_pending == NULL))
1737 					tp->t_tfo_pending =
1738 					    tcp_fastopen_alloc_counter();
1739 			} else
1740 				tp->t_flags &= ~TF_FASTOPEN;
1741 			goto unlock_and_done;
1742 #endif
1743 
1744 		default:
1745 			INP_WUNLOCK(inp);
1746 			error = ENOPROTOOPT;
1747 			break;
1748 		}
1749 		break;
1750 
1751 	case SOPT_GET:
1752 		tp = intotcpcb(inp);
1753 		switch (sopt->sopt_name) {
1754 #ifdef TCP_SIGNATURE
1755 		case TCP_MD5SIG:
1756 			optval = (tp->t_flags & TF_SIGNATURE) ? 1 : 0;
1757 			INP_WUNLOCK(inp);
1758 			error = sooptcopyout(sopt, &optval, sizeof optval);
1759 			break;
1760 #endif
1761 
1762 		case TCP_NODELAY:
1763 			optval = tp->t_flags & TF_NODELAY;
1764 			INP_WUNLOCK(inp);
1765 			error = sooptcopyout(sopt, &optval, sizeof optval);
1766 			break;
1767 		case TCP_MAXSEG:
1768 			optval = tp->t_maxseg;
1769 			INP_WUNLOCK(inp);
1770 			error = sooptcopyout(sopt, &optval, sizeof optval);
1771 			break;
1772 		case TCP_NOOPT:
1773 			optval = tp->t_flags & TF_NOOPT;
1774 			INP_WUNLOCK(inp);
1775 			error = sooptcopyout(sopt, &optval, sizeof optval);
1776 			break;
1777 		case TCP_NOPUSH:
1778 			optval = tp->t_flags & TF_NOPUSH;
1779 			INP_WUNLOCK(inp);
1780 			error = sooptcopyout(sopt, &optval, sizeof optval);
1781 			break;
1782 		case TCP_INFO:
1783 			tcp_fill_info(tp, &ti);
1784 			INP_WUNLOCK(inp);
1785 			error = sooptcopyout(sopt, &ti, sizeof ti);
1786 			break;
1787 		case TCP_CONGESTION:
1788 			len = strlcpy(buf, CC_ALGO(tp)->name, TCP_CA_NAME_MAX);
1789 			INP_WUNLOCK(inp);
1790 			error = sooptcopyout(sopt, buf, len + 1);
1791 			break;
1792 		case TCP_KEEPIDLE:
1793 		case TCP_KEEPINTVL:
1794 		case TCP_KEEPINIT:
1795 		case TCP_KEEPCNT:
1796 			switch (sopt->sopt_name) {
1797 			case TCP_KEEPIDLE:
1798 				ui = tp->t_keepidle / hz;
1799 				break;
1800 			case TCP_KEEPINTVL:
1801 				ui = tp->t_keepintvl / hz;
1802 				break;
1803 			case TCP_KEEPINIT:
1804 				ui = tp->t_keepinit / hz;
1805 				break;
1806 			case TCP_KEEPCNT:
1807 				ui = tp->t_keepcnt;
1808 				break;
1809 			}
1810 			INP_WUNLOCK(inp);
1811 			error = sooptcopyout(sopt, &ui, sizeof(ui));
1812 			break;
1813 #ifdef TCPPCAP
1814 		case TCP_PCAP_OUT:
1815 		case TCP_PCAP_IN:
1816 			optval = tcp_pcap_get_sock_max(TCP_PCAP_OUT ?
1817 					&(tp->t_outpkts) : &(tp->t_inpkts));
1818 			INP_WUNLOCK(inp);
1819 			error = sooptcopyout(sopt, &optval, sizeof optval);
1820 			break;
1821 #endif
1822 
1823 #ifdef TCP_RFC7413
1824 		case TCP_FASTOPEN:
1825 			optval = tp->t_flags & TF_FASTOPEN;
1826 			INP_WUNLOCK(inp);
1827 			error = sooptcopyout(sopt, &optval, sizeof optval);
1828 			break;
1829 #endif
1830 		default:
1831 			INP_WUNLOCK(inp);
1832 			error = ENOPROTOOPT;
1833 			break;
1834 		}
1835 		break;
1836 	}
1837 	return (error);
1838 }
1839 #undef INP_WLOCK_RECHECK
1840 
1841 /*
1842  * Attach TCP protocol to socket, allocating
1843  * internet protocol control block, tcp control block,
1844  * bufer space, and entering LISTEN state if to accept connections.
1845  */
1846 static int
1847 tcp_attach(struct socket *so)
1848 {
1849 	struct tcpcb *tp;
1850 	struct inpcb *inp;
1851 	int error;
1852 
1853 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
1854 		error = soreserve(so, V_tcp_sendspace, V_tcp_recvspace);
1855 		if (error)
1856 			return (error);
1857 	}
1858 	so->so_rcv.sb_flags |= SB_AUTOSIZE;
1859 	so->so_snd.sb_flags |= SB_AUTOSIZE;
1860 	INP_INFO_RLOCK(&V_tcbinfo);
1861 	error = in_pcballoc(so, &V_tcbinfo);
1862 	if (error) {
1863 		INP_INFO_RUNLOCK(&V_tcbinfo);
1864 		return (error);
1865 	}
1866 	inp = sotoinpcb(so);
1867 #ifdef INET6
1868 	if (inp->inp_vflag & INP_IPV6PROTO) {
1869 		inp->inp_vflag |= INP_IPV6;
1870 		inp->in6p_hops = -1;	/* use kernel default */
1871 	}
1872 	else
1873 #endif
1874 	inp->inp_vflag |= INP_IPV4;
1875 	tp = tcp_newtcpcb(inp);
1876 	if (tp == NULL) {
1877 		in_pcbdetach(inp);
1878 		in_pcbfree(inp);
1879 		INP_INFO_RUNLOCK(&V_tcbinfo);
1880 		return (ENOBUFS);
1881 	}
1882 	tp->t_state = TCPS_CLOSED;
1883 	INP_WUNLOCK(inp);
1884 	INP_INFO_RUNLOCK(&V_tcbinfo);
1885 	TCPSTAT_INC(tcps_states[TCPS_CLOSED]);
1886 	return (0);
1887 }
1888 
1889 /*
1890  * Initiate (or continue) disconnect.
1891  * If embryonic state, just send reset (once).
1892  * If in ``let data drain'' option and linger null, just drop.
1893  * Otherwise (hard), mark socket disconnecting and drop
1894  * current input data; switch states based on user close, and
1895  * send segment to peer (with FIN).
1896  */
1897 static void
1898 tcp_disconnect(struct tcpcb *tp)
1899 {
1900 	struct inpcb *inp = tp->t_inpcb;
1901 	struct socket *so = inp->inp_socket;
1902 
1903 	INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
1904 	INP_WLOCK_ASSERT(inp);
1905 
1906 	/*
1907 	 * Neither tcp_close() nor tcp_drop() should return NULL, as the
1908 	 * socket is still open.
1909 	 */
1910 	if (tp->t_state < TCPS_ESTABLISHED) {
1911 		tp = tcp_close(tp);
1912 		KASSERT(tp != NULL,
1913 		    ("tcp_disconnect: tcp_close() returned NULL"));
1914 	} else if ((so->so_options & SO_LINGER) && so->so_linger == 0) {
1915 		tp = tcp_drop(tp, 0);
1916 		KASSERT(tp != NULL,
1917 		    ("tcp_disconnect: tcp_drop() returned NULL"));
1918 	} else {
1919 		soisdisconnecting(so);
1920 		sbflush(&so->so_rcv);
1921 		tcp_usrclosed(tp);
1922 		if (!(inp->inp_flags & INP_DROPPED))
1923 			tp->t_fb->tfb_tcp_output(tp);
1924 	}
1925 }
1926 
1927 /*
1928  * User issued close, and wish to trail through shutdown states:
1929  * if never received SYN, just forget it.  If got a SYN from peer,
1930  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
1931  * If already got a FIN from peer, then almost done; go to LAST_ACK
1932  * state.  In all other cases, have already sent FIN to peer (e.g.
1933  * after PRU_SHUTDOWN), and just have to play tedious game waiting
1934  * for peer to send FIN or not respond to keep-alives, etc.
1935  * We can let the user exit from the close as soon as the FIN is acked.
1936  */
1937 static void
1938 tcp_usrclosed(struct tcpcb *tp)
1939 {
1940 
1941 	INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
1942 	INP_WLOCK_ASSERT(tp->t_inpcb);
1943 
1944 	switch (tp->t_state) {
1945 	case TCPS_LISTEN:
1946 #ifdef TCP_OFFLOAD
1947 		tcp_offload_listen_stop(tp);
1948 #endif
1949 		tcp_state_change(tp, TCPS_CLOSED);
1950 		/* FALLTHROUGH */
1951 	case TCPS_CLOSED:
1952 		tp = tcp_close(tp);
1953 		/*
1954 		 * tcp_close() should never return NULL here as the socket is
1955 		 * still open.
1956 		 */
1957 		KASSERT(tp != NULL,
1958 		    ("tcp_usrclosed: tcp_close() returned NULL"));
1959 		break;
1960 
1961 	case TCPS_SYN_SENT:
1962 	case TCPS_SYN_RECEIVED:
1963 		tp->t_flags |= TF_NEEDFIN;
1964 		break;
1965 
1966 	case TCPS_ESTABLISHED:
1967 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
1968 		break;
1969 
1970 	case TCPS_CLOSE_WAIT:
1971 		tcp_state_change(tp, TCPS_LAST_ACK);
1972 		break;
1973 	}
1974 	if (tp->t_state >= TCPS_FIN_WAIT_2) {
1975 		soisdisconnected(tp->t_inpcb->inp_socket);
1976 		/* Prevent the connection hanging in FIN_WAIT_2 forever. */
1977 		if (tp->t_state == TCPS_FIN_WAIT_2) {
1978 			int timeout;
1979 
1980 			timeout = (tcp_fast_finwait2_recycle) ?
1981 			    tcp_finwait2_timeout : TP_MAXIDLE(tp);
1982 			tcp_timer_activate(tp, TT_2MSL, timeout);
1983 		}
1984 	}
1985 }
1986 
1987 #ifdef DDB
1988 static void
1989 db_print_indent(int indent)
1990 {
1991 	int i;
1992 
1993 	for (i = 0; i < indent; i++)
1994 		db_printf(" ");
1995 }
1996 
1997 static void
1998 db_print_tstate(int t_state)
1999 {
2000 
2001 	switch (t_state) {
2002 	case TCPS_CLOSED:
2003 		db_printf("TCPS_CLOSED");
2004 		return;
2005 
2006 	case TCPS_LISTEN:
2007 		db_printf("TCPS_LISTEN");
2008 		return;
2009 
2010 	case TCPS_SYN_SENT:
2011 		db_printf("TCPS_SYN_SENT");
2012 		return;
2013 
2014 	case TCPS_SYN_RECEIVED:
2015 		db_printf("TCPS_SYN_RECEIVED");
2016 		return;
2017 
2018 	case TCPS_ESTABLISHED:
2019 		db_printf("TCPS_ESTABLISHED");
2020 		return;
2021 
2022 	case TCPS_CLOSE_WAIT:
2023 		db_printf("TCPS_CLOSE_WAIT");
2024 		return;
2025 
2026 	case TCPS_FIN_WAIT_1:
2027 		db_printf("TCPS_FIN_WAIT_1");
2028 		return;
2029 
2030 	case TCPS_CLOSING:
2031 		db_printf("TCPS_CLOSING");
2032 		return;
2033 
2034 	case TCPS_LAST_ACK:
2035 		db_printf("TCPS_LAST_ACK");
2036 		return;
2037 
2038 	case TCPS_FIN_WAIT_2:
2039 		db_printf("TCPS_FIN_WAIT_2");
2040 		return;
2041 
2042 	case TCPS_TIME_WAIT:
2043 		db_printf("TCPS_TIME_WAIT");
2044 		return;
2045 
2046 	default:
2047 		db_printf("unknown");
2048 		return;
2049 	}
2050 }
2051 
2052 static void
2053 db_print_tflags(u_int t_flags)
2054 {
2055 	int comma;
2056 
2057 	comma = 0;
2058 	if (t_flags & TF_ACKNOW) {
2059 		db_printf("%sTF_ACKNOW", comma ? ", " : "");
2060 		comma = 1;
2061 	}
2062 	if (t_flags & TF_DELACK) {
2063 		db_printf("%sTF_DELACK", comma ? ", " : "");
2064 		comma = 1;
2065 	}
2066 	if (t_flags & TF_NODELAY) {
2067 		db_printf("%sTF_NODELAY", comma ? ", " : "");
2068 		comma = 1;
2069 	}
2070 	if (t_flags & TF_NOOPT) {
2071 		db_printf("%sTF_NOOPT", comma ? ", " : "");
2072 		comma = 1;
2073 	}
2074 	if (t_flags & TF_SENTFIN) {
2075 		db_printf("%sTF_SENTFIN", comma ? ", " : "");
2076 		comma = 1;
2077 	}
2078 	if (t_flags & TF_REQ_SCALE) {
2079 		db_printf("%sTF_REQ_SCALE", comma ? ", " : "");
2080 		comma = 1;
2081 	}
2082 	if (t_flags & TF_RCVD_SCALE) {
2083 		db_printf("%sTF_RECVD_SCALE", comma ? ", " : "");
2084 		comma = 1;
2085 	}
2086 	if (t_flags & TF_REQ_TSTMP) {
2087 		db_printf("%sTF_REQ_TSTMP", comma ? ", " : "");
2088 		comma = 1;
2089 	}
2090 	if (t_flags & TF_RCVD_TSTMP) {
2091 		db_printf("%sTF_RCVD_TSTMP", comma ? ", " : "");
2092 		comma = 1;
2093 	}
2094 	if (t_flags & TF_SACK_PERMIT) {
2095 		db_printf("%sTF_SACK_PERMIT", comma ? ", " : "");
2096 		comma = 1;
2097 	}
2098 	if (t_flags & TF_NEEDSYN) {
2099 		db_printf("%sTF_NEEDSYN", comma ? ", " : "");
2100 		comma = 1;
2101 	}
2102 	if (t_flags & TF_NEEDFIN) {
2103 		db_printf("%sTF_NEEDFIN", comma ? ", " : "");
2104 		comma = 1;
2105 	}
2106 	if (t_flags & TF_NOPUSH) {
2107 		db_printf("%sTF_NOPUSH", comma ? ", " : "");
2108 		comma = 1;
2109 	}
2110 	if (t_flags & TF_MORETOCOME) {
2111 		db_printf("%sTF_MORETOCOME", comma ? ", " : "");
2112 		comma = 1;
2113 	}
2114 	if (t_flags & TF_LQ_OVERFLOW) {
2115 		db_printf("%sTF_LQ_OVERFLOW", comma ? ", " : "");
2116 		comma = 1;
2117 	}
2118 	if (t_flags & TF_LASTIDLE) {
2119 		db_printf("%sTF_LASTIDLE", comma ? ", " : "");
2120 		comma = 1;
2121 	}
2122 	if (t_flags & TF_RXWIN0SENT) {
2123 		db_printf("%sTF_RXWIN0SENT", comma ? ", " : "");
2124 		comma = 1;
2125 	}
2126 	if (t_flags & TF_FASTRECOVERY) {
2127 		db_printf("%sTF_FASTRECOVERY", comma ? ", " : "");
2128 		comma = 1;
2129 	}
2130 	if (t_flags & TF_CONGRECOVERY) {
2131 		db_printf("%sTF_CONGRECOVERY", comma ? ", " : "");
2132 		comma = 1;
2133 	}
2134 	if (t_flags & TF_WASFRECOVERY) {
2135 		db_printf("%sTF_WASFRECOVERY", comma ? ", " : "");
2136 		comma = 1;
2137 	}
2138 	if (t_flags & TF_SIGNATURE) {
2139 		db_printf("%sTF_SIGNATURE", comma ? ", " : "");
2140 		comma = 1;
2141 	}
2142 	if (t_flags & TF_FORCEDATA) {
2143 		db_printf("%sTF_FORCEDATA", comma ? ", " : "");
2144 		comma = 1;
2145 	}
2146 	if (t_flags & TF_TSO) {
2147 		db_printf("%sTF_TSO", comma ? ", " : "");
2148 		comma = 1;
2149 	}
2150 	if (t_flags & TF_ECN_PERMIT) {
2151 		db_printf("%sTF_ECN_PERMIT", comma ? ", " : "");
2152 		comma = 1;
2153 	}
2154 	if (t_flags & TF_FASTOPEN) {
2155 		db_printf("%sTF_FASTOPEN", comma ? ", " : "");
2156 		comma = 1;
2157 	}
2158 }
2159 
2160 static void
2161 db_print_toobflags(char t_oobflags)
2162 {
2163 	int comma;
2164 
2165 	comma = 0;
2166 	if (t_oobflags & TCPOOB_HAVEDATA) {
2167 		db_printf("%sTCPOOB_HAVEDATA", comma ? ", " : "");
2168 		comma = 1;
2169 	}
2170 	if (t_oobflags & TCPOOB_HADDATA) {
2171 		db_printf("%sTCPOOB_HADDATA", comma ? ", " : "");
2172 		comma = 1;
2173 	}
2174 }
2175 
2176 static void
2177 db_print_tcpcb(struct tcpcb *tp, const char *name, int indent)
2178 {
2179 
2180 	db_print_indent(indent);
2181 	db_printf("%s at %p\n", name, tp);
2182 
2183 	indent += 2;
2184 
2185 	db_print_indent(indent);
2186 	db_printf("t_segq first: %p   t_segqlen: %d   t_dupacks: %d\n",
2187 	   LIST_FIRST(&tp->t_segq), tp->t_segqlen, tp->t_dupacks);
2188 
2189 	db_print_indent(indent);
2190 	db_printf("tt_rexmt: %p   tt_persist: %p   tt_keep: %p\n",
2191 	    &tp->t_timers->tt_rexmt, &tp->t_timers->tt_persist, &tp->t_timers->tt_keep);
2192 
2193 	db_print_indent(indent);
2194 	db_printf("tt_2msl: %p   tt_delack: %p   t_inpcb: %p\n", &tp->t_timers->tt_2msl,
2195 	    &tp->t_timers->tt_delack, tp->t_inpcb);
2196 
2197 	db_print_indent(indent);
2198 	db_printf("t_state: %d (", tp->t_state);
2199 	db_print_tstate(tp->t_state);
2200 	db_printf(")\n");
2201 
2202 	db_print_indent(indent);
2203 	db_printf("t_flags: 0x%x (", tp->t_flags);
2204 	db_print_tflags(tp->t_flags);
2205 	db_printf(")\n");
2206 
2207 	db_print_indent(indent);
2208 	db_printf("snd_una: 0x%08x   snd_max: 0x%08x   snd_nxt: x0%08x\n",
2209 	    tp->snd_una, tp->snd_max, tp->snd_nxt);
2210 
2211 	db_print_indent(indent);
2212 	db_printf("snd_up: 0x%08x   snd_wl1: 0x%08x   snd_wl2: 0x%08x\n",
2213 	   tp->snd_up, tp->snd_wl1, tp->snd_wl2);
2214 
2215 	db_print_indent(indent);
2216 	db_printf("iss: 0x%08x   irs: 0x%08x   rcv_nxt: 0x%08x\n",
2217 	    tp->iss, tp->irs, tp->rcv_nxt);
2218 
2219 	db_print_indent(indent);
2220 	db_printf("rcv_adv: 0x%08x   rcv_wnd: %lu   rcv_up: 0x%08x\n",
2221 	    tp->rcv_adv, tp->rcv_wnd, tp->rcv_up);
2222 
2223 	db_print_indent(indent);
2224 	db_printf("snd_wnd: %lu   snd_cwnd: %lu\n",
2225 	   tp->snd_wnd, tp->snd_cwnd);
2226 
2227 	db_print_indent(indent);
2228 	db_printf("snd_ssthresh: %lu   snd_recover: "
2229 	    "0x%08x\n", tp->snd_ssthresh, tp->snd_recover);
2230 
2231 	db_print_indent(indent);
2232 	db_printf("t_rcvtime: %u   t_startime: %u\n",
2233 	    tp->t_rcvtime, tp->t_starttime);
2234 
2235 	db_print_indent(indent);
2236 	db_printf("t_rttime: %u   t_rtsq: 0x%08x\n",
2237 	    tp->t_rtttime, tp->t_rtseq);
2238 
2239 	db_print_indent(indent);
2240 	db_printf("t_rxtcur: %d   t_maxseg: %u   t_srtt: %d\n",
2241 	    tp->t_rxtcur, tp->t_maxseg, tp->t_srtt);
2242 
2243 	db_print_indent(indent);
2244 	db_printf("t_rttvar: %d   t_rxtshift: %d   t_rttmin: %u   "
2245 	    "t_rttbest: %u\n", tp->t_rttvar, tp->t_rxtshift, tp->t_rttmin,
2246 	    tp->t_rttbest);
2247 
2248 	db_print_indent(indent);
2249 	db_printf("t_rttupdated: %lu   max_sndwnd: %lu   t_softerror: %d\n",
2250 	    tp->t_rttupdated, tp->max_sndwnd, tp->t_softerror);
2251 
2252 	db_print_indent(indent);
2253 	db_printf("t_oobflags: 0x%x (", tp->t_oobflags);
2254 	db_print_toobflags(tp->t_oobflags);
2255 	db_printf(")   t_iobc: 0x%02x\n", tp->t_iobc);
2256 
2257 	db_print_indent(indent);
2258 	db_printf("snd_scale: %u   rcv_scale: %u   request_r_scale: %u\n",
2259 	    tp->snd_scale, tp->rcv_scale, tp->request_r_scale);
2260 
2261 	db_print_indent(indent);
2262 	db_printf("ts_recent: %u   ts_recent_age: %u\n",
2263 	    tp->ts_recent, tp->ts_recent_age);
2264 
2265 	db_print_indent(indent);
2266 	db_printf("ts_offset: %u   last_ack_sent: 0x%08x   snd_cwnd_prev: "
2267 	    "%lu\n", tp->ts_offset, tp->last_ack_sent, tp->snd_cwnd_prev);
2268 
2269 	db_print_indent(indent);
2270 	db_printf("snd_ssthresh_prev: %lu   snd_recover_prev: 0x%08x   "
2271 	    "t_badrxtwin: %u\n", tp->snd_ssthresh_prev,
2272 	    tp->snd_recover_prev, tp->t_badrxtwin);
2273 
2274 	db_print_indent(indent);
2275 	db_printf("snd_numholes: %d  snd_holes first: %p\n",
2276 	    tp->snd_numholes, TAILQ_FIRST(&tp->snd_holes));
2277 
2278 	db_print_indent(indent);
2279 	db_printf("snd_fack: 0x%08x   rcv_numsacks: %d   sack_newdata: "
2280 	    "0x%08x\n", tp->snd_fack, tp->rcv_numsacks, tp->sack_newdata);
2281 
2282 	/* Skip sackblks, sackhint. */
2283 
2284 	db_print_indent(indent);
2285 	db_printf("t_rttlow: %d   rfbuf_ts: %u   rfbuf_cnt: %d\n",
2286 	    tp->t_rttlow, tp->rfbuf_ts, tp->rfbuf_cnt);
2287 }
2288 
2289 DB_SHOW_COMMAND(tcpcb, db_show_tcpcb)
2290 {
2291 	struct tcpcb *tp;
2292 
2293 	if (!have_addr) {
2294 		db_printf("usage: show tcpcb <addr>\n");
2295 		return;
2296 	}
2297 	tp = (struct tcpcb *)addr;
2298 
2299 	db_print_tcpcb(tp, "tcpcb", 0);
2300 }
2301 #endif
2302