xref: /dflybsd-src/sys/netinet/tcp_usrreq.c (revision bc49aa1be5400e3bdd801519c6936e8947d5d432)
1 /*
2  * Copyright (c) 2003, 2004 Jeffrey M. Hsu.  All rights reserved.
3  * Copyright (c) 2003, 2004 The DragonFly Project.  All rights reserved.
4  *
5  * This code is derived from software contributed to The DragonFly Project
6  * by Jeffrey M. Hsu.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of The DragonFly Project nor the names of its
17  *    contributors may be used to endorse or promote products derived
18  *    from this software without specific, prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
24  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 /*
35  * Copyright (c) 2003, 2004 Jeffrey M. Hsu.  All rights reserved.
36  *
37  * License terms: all terms for the DragonFly license above plus the following:
38  *
39  * 4. All advertising materials mentioning features or use of this software
40  *    must display the following acknowledgement:
41  *
42  *	This product includes software developed by Jeffrey M. Hsu
43  *	for the DragonFly Project.
44  *
45  *    This requirement may be waived with permission from Jeffrey Hsu.
46  *    This requirement will sunset and may be removed on July 8 2005,
47  *    after which the standard DragonFly license (as shown above) will
48  *    apply.
49  */
50 
51 /*
52  * Copyright (c) 1982, 1986, 1988, 1993
53  *	The Regents of the University of California.  All rights reserved.
54  *
55  * Redistribution and use in source and binary forms, with or without
56  * modification, are permitted provided that the following conditions
57  * are met:
58  * 1. Redistributions of source code must retain the above copyright
59  *    notice, this list of conditions and the following disclaimer.
60  * 2. Redistributions in binary form must reproduce the above copyright
61  *    notice, this list of conditions and the following disclaimer in the
62  *    documentation and/or other materials provided with the distribution.
63  * 3. All advertising materials mentioning features or use of this software
64  *    must display the following acknowledgement:
65  *	This product includes software developed by the University of
66  *	California, Berkeley and its contributors.
67  * 4. Neither the name of the University nor the names of its contributors
68  *    may be used to endorse or promote products derived from this software
69  *    without specific prior written permission.
70  *
71  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
72  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
73  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
74  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
75  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
76  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
77  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
78  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
79  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
80  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
81  * SUCH DAMAGE.
82  *
83  *	From: @(#)tcp_usrreq.c	8.2 (Berkeley) 1/3/94
84  * $FreeBSD: src/sys/netinet/tcp_usrreq.c,v 1.51.2.17 2002/10/11 11:46:44 ume Exp $
85  * $DragonFly: src/sys/netinet/tcp_usrreq.c,v 1.25 2004/07/08 22:07:35 hsu Exp $
86  */
87 
88 #include "opt_ipsec.h"
89 #include "opt_inet6.h"
90 #include "opt_tcpdebug.h"
91 
92 #include <sys/param.h>
93 #include <sys/systm.h>
94 #include <sys/kernel.h>
95 #include <sys/malloc.h>
96 #include <sys/sysctl.h>
97 #include <sys/globaldata.h>
98 #include <sys/thread.h>
99 
100 #include <sys/mbuf.h>
101 #ifdef INET6
102 #include <sys/domain.h>
103 #endif /* INET6 */
104 #include <sys/socket.h>
105 #include <sys/socketvar.h>
106 #include <sys/protosw.h>
107 
108 #include <sys/msgport2.h>
109 
110 #include <net/if.h>
111 #include <net/netisr.h>
112 #include <net/route.h>
113 
114 #include <netinet/in.h>
115 #include <netinet/in_systm.h>
116 #ifdef INET6
117 #include <netinet/ip6.h>
118 #endif
119 #include <netinet/in_pcb.h>
120 #ifdef INET6
121 #include <netinet6/in6_pcb.h>
122 #endif
123 #include <netinet/in_var.h>
124 #include <netinet/ip_var.h>
125 #ifdef INET6
126 #include <netinet6/ip6_var.h>
127 #endif
128 #include <netinet/tcp.h>
129 #include <netinet/tcp_fsm.h>
130 #include <netinet/tcp_seq.h>
131 #include <netinet/tcp_timer.h>
132 #include <netinet/tcp_var.h>
133 #include <netinet/tcpip.h>
134 #ifdef TCPDEBUG
135 #include <netinet/tcp_debug.h>
136 #endif
137 
138 #ifdef IPSEC
139 #include <netinet6/ipsec.h>
140 #endif /*IPSEC*/
141 
142 /*
143  * TCP protocol interface to socket abstraction.
144  */
145 extern	char *tcpstates[];	/* XXX ??? */
146 
147 static int	tcp_attach (struct socket *, struct pru_attach_info *);
148 static int	tcp_connect (struct tcpcb *, struct sockaddr *,
149 				 struct thread *);
150 #ifdef INET6
151 static int	tcp6_connect (struct tcpcb *, struct sockaddr *,
152 				 struct thread *);
153 #endif /* INET6 */
154 static struct tcpcb *
155 		tcp_disconnect (struct tcpcb *);
156 static struct tcpcb *
157 		tcp_usrclosed (struct tcpcb *);
158 
159 #ifdef TCPDEBUG
160 #define	TCPDEBUG0	int ostate = 0
161 #define	TCPDEBUG1()	ostate = tp ? tp->t_state : 0
162 #define	TCPDEBUG2(req)	if (tp && (so->so_options & SO_DEBUG)) \
163 				tcp_trace(TA_USER, ostate, tp, 0, 0, req)
164 #else
165 #define	TCPDEBUG0
166 #define	TCPDEBUG1()
167 #define	TCPDEBUG2(req)
168 #endif
169 
170 /*
171  * TCP attaches to socket via pru_attach(), reserving space,
172  * and an internet control block.
173  */
174 static int
175 tcp_usr_attach(struct socket *so, int proto, struct pru_attach_info *ai)
176 {
177 	int s = splnet();
178 	int error;
179 	struct inpcb *inp = sotoinpcb(so);
180 	struct tcpcb *tp = 0;
181 	TCPDEBUG0;
182 
183 	TCPDEBUG1();
184 	if (inp) {
185 		error = EISCONN;
186 		goto out;
187 	}
188 
189 	error = tcp_attach(so, ai);
190 	if (error)
191 		goto out;
192 
193 	if ((so->so_options & SO_LINGER) && so->so_linger == 0)
194 		so->so_linger = TCP_LINGERTIME;
195 	tp = sototcpcb(so);
196 out:
197 	TCPDEBUG2(PRU_ATTACH);
198 	splx(s);
199 	return error;
200 }
201 
202 /*
203  * pru_detach() detaches the TCP protocol from the socket.
204  * If the protocol state is non-embryonic, then can't
205  * do this directly: have to initiate a pru_disconnect(),
206  * which may finish later; embryonic TCB's can just
207  * be discarded here.
208  */
209 static int
210 tcp_usr_detach(struct socket *so)
211 {
212 	int s = splnet();
213 	int error = 0;
214 	struct inpcb *inp = sotoinpcb(so);
215 	struct tcpcb *tp;
216 	TCPDEBUG0;
217 
218 	if (inp == 0) {
219 		splx(s);
220 		return EINVAL;	/* XXX */
221 	}
222 	tp = intotcpcb(inp);
223 	TCPDEBUG1();
224 	tp = tcp_disconnect(tp);
225 
226 	TCPDEBUG2(PRU_DETACH);
227 	splx(s);
228 	return error;
229 }
230 
231 #define	COMMON_START()	TCPDEBUG0; \
232 			do { \
233 				     if (inp == 0) { \
234 					     splx(s); \
235 					     return EINVAL; \
236 				     } \
237 				     tp = intotcpcb(inp); \
238 				     TCPDEBUG1(); \
239 		     } while(0)
240 
241 #define COMMON_END(req)	out: TCPDEBUG2(req); splx(s); return error; goto out
242 
243 
244 /*
245  * Give the socket an address.
246  */
247 static int
248 tcp_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
249 {
250 	int s = splnet();
251 	int error = 0;
252 	struct inpcb *inp = sotoinpcb(so);
253 	struct tcpcb *tp;
254 	struct sockaddr_in *sinp;
255 
256 	COMMON_START();
257 
258 	/*
259 	 * Must check for multicast addresses and disallow binding
260 	 * to them.
261 	 */
262 	sinp = (struct sockaddr_in *)nam;
263 	if (sinp->sin_family == AF_INET &&
264 	    IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
265 		error = EAFNOSUPPORT;
266 		goto out;
267 	}
268 	error = in_pcbbind(inp, nam, td);
269 	if (error)
270 		goto out;
271 	COMMON_END(PRU_BIND);
272 
273 }
274 
275 #ifdef INET6
276 static int
277 tcp6_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
278 {
279 	int s = splnet();
280 	int error = 0;
281 	struct inpcb *inp = sotoinpcb(so);
282 	struct tcpcb *tp;
283 	struct sockaddr_in6 *sin6p;
284 
285 	COMMON_START();
286 
287 	/*
288 	 * Must check for multicast addresses and disallow binding
289 	 * to them.
290 	 */
291 	sin6p = (struct sockaddr_in6 *)nam;
292 	if (sin6p->sin6_family == AF_INET6 &&
293 	    IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr)) {
294 		error = EAFNOSUPPORT;
295 		goto out;
296 	}
297 	inp->inp_vflag &= ~INP_IPV4;
298 	inp->inp_vflag |= INP_IPV6;
299 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
300 		if (IN6_IS_ADDR_UNSPECIFIED(&sin6p->sin6_addr))
301 			inp->inp_vflag |= INP_IPV4;
302 		else if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
303 			struct sockaddr_in sin;
304 
305 			in6_sin6_2_sin(&sin, sin6p);
306 			inp->inp_vflag |= INP_IPV4;
307 			inp->inp_vflag &= ~INP_IPV6;
308 			error = in_pcbbind(inp, (struct sockaddr *)&sin, td);
309 			goto out;
310 		}
311 	}
312 	error = in6_pcbbind(inp, nam, td);
313 	if (error)
314 		goto out;
315 	COMMON_END(PRU_BIND);
316 }
317 #endif /* INET6 */
318 
319 #ifdef SMP
320 struct netmsg_inswildcard {
321 	struct lwkt_msg		nm_lmsg;
322 	struct inpcb		*nm_inp;
323 	struct inpcbinfo	*nm_pcbinfo;
324 };
325 
326 static int
327 in_pcbinswildcardhash_handler(struct lwkt_msg *msg0)
328 {
329 	struct netmsg_inswildcard *msg = (struct netmsg_inswildcard *)msg0;
330 
331 	in_pcbinswildcardhash_oncpu(msg->nm_inp, msg->nm_pcbinfo);
332 	lwkt_replymsg(&msg->nm_lmsg, 0);
333 	return (EASYNC);
334 }
335 #endif
336 
337 /*
338  * Prepare to accept connections.
339  */
340 static int
341 tcp_usr_listen(struct socket *so, struct thread *td)
342 {
343 	int s = splnet();
344 	int error = 0;
345 	struct inpcb *inp = sotoinpcb(so);
346 	struct tcpcb *tp;
347 #ifdef SMP
348 	int cpu;
349 #endif
350 
351 	COMMON_START();
352 	if (inp->inp_lport == 0) {
353 		error = in_pcbbind(inp, NULL, td);
354 		if (error != 0)
355 			goto out;
356 	}
357 
358 	tp->t_state = TCPS_LISTEN;
359 #ifdef SMP
360 	for (cpu = 0; cpu < ncpus2; cpu++) {
361 		struct netmsg_inswildcard *msg;
362 
363 		if (cpu == mycpu->gd_cpuid) {
364 			in_pcbinswildcardhash_oncpu(inp, &tcbinfo[cpu]);
365 			continue;
366 		}
367 
368 		msg = malloc(sizeof(struct netmsg_inswildcard), M_LWKTMSG,
369 		    M_INTWAIT);
370 		lwkt_initmsg(&msg->nm_lmsg, &netisr_afree_rport, 0,
371 		    lwkt_cmd_func(in_pcbinswildcardhash_handler),
372 		    lwkt_cmd_op_none);
373 		msg->nm_inp = inp;
374 		msg->nm_pcbinfo = &tcbinfo[cpu];
375 		lwkt_sendmsg(tcp_cport(cpu), &msg->nm_lmsg);
376 	}
377 	inp->inp_flags |= INP_WILDCARD_MP;
378 #else
379 	in_pcbinswildcardhash(inp);
380 #endif
381 	COMMON_END(PRU_LISTEN);
382 }
383 
384 #ifdef INET6
385 static int
386 tcp6_usr_listen(struct socket *so, struct thread *td)
387 {
388 	int s = splnet();
389 	int error = 0;
390 	struct inpcb *inp = sotoinpcb(so);
391 	struct tcpcb *tp;
392 
393 	COMMON_START();
394 	if (inp->inp_lport == 0) {
395 		inp->inp_vflag &= ~INP_IPV4;
396 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
397 			inp->inp_vflag |= INP_IPV4;
398 		error = in6_pcbbind(inp, (struct sockaddr *)0, td);
399 	}
400 	if (error == 0)
401 		tp->t_state = TCPS_LISTEN;
402 	in_pcbinswildcardhash(inp);
403 	COMMON_END(PRU_LISTEN);
404 }
405 #endif /* INET6 */
406 
407 /*
408  * Initiate connection to peer.
409  * Create a template for use in transmissions on this connection.
410  * Enter SYN_SENT state, and mark socket as connecting.
411  * Start keep-alive timer, and seed output sequence space.
412  * Send initial segment on connection.
413  */
414 static int
415 tcp_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
416 {
417 	int s = splnet();
418 	int error = 0;
419 	struct inpcb *inp = sotoinpcb(so);
420 	struct tcpcb *tp;
421 	struct sockaddr_in *sinp;
422 
423 	COMMON_START();
424 
425 	/*
426 	 * Must disallow TCP ``connections'' to multicast addresses.
427 	 */
428 	sinp = (struct sockaddr_in *)nam;
429 	if (sinp->sin_family == AF_INET
430 	    && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
431 		error = EAFNOSUPPORT;
432 		goto out;
433 	}
434 
435 	prison_remote_ip(td, 0, &sinp->sin_addr.s_addr);
436 
437 	if ((error = tcp_connect(tp, nam, td)) != 0)
438 		goto out;
439 	error = tcp_output(tp);
440 	COMMON_END(PRU_CONNECT);
441 }
442 
443 #ifdef INET6
444 static int
445 tcp6_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
446 {
447 	int s = splnet();
448 	int error = 0;
449 	struct inpcb *inp = sotoinpcb(so);
450 	struct tcpcb *tp;
451 	struct sockaddr_in6 *sin6p;
452 
453 	COMMON_START();
454 
455 	/*
456 	 * Must disallow TCP ``connections'' to multicast addresses.
457 	 */
458 	sin6p = (struct sockaddr_in6 *)nam;
459 	if (sin6p->sin6_family == AF_INET6
460 	    && IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr)) {
461 		error = EAFNOSUPPORT;
462 		goto out;
463 	}
464 
465 	if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
466 		struct sockaddr_in sin;
467 
468 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
469 			error = EINVAL;
470 			goto out;
471 		}
472 
473 		in6_sin6_2_sin(&sin, sin6p);
474 		inp->inp_vflag |= INP_IPV4;
475 		inp->inp_vflag &= ~INP_IPV6;
476 		if ((error = tcp_connect(tp, (struct sockaddr *)&sin, td)) != 0)
477 			goto out;
478 		error = tcp_output(tp);
479 		goto out;
480 	}
481 	inp->inp_vflag &= ~INP_IPV4;
482 	inp->inp_vflag |= INP_IPV6;
483 	inp->inp_inc.inc_isipv6 = 1;
484 	if ((error = tcp6_connect(tp, nam, td)) != 0)
485 		goto out;
486 	error = tcp_output(tp);
487 	COMMON_END(PRU_CONNECT);
488 }
489 #endif /* INET6 */
490 
491 /*
492  * Initiate disconnect from peer.
493  * If connection never passed embryonic stage, just drop;
494  * else if don't need to let data drain, then can just drop anyways,
495  * else have to begin TCP shutdown process: mark socket disconnecting,
496  * drain unread data, state switch to reflect user close, and
497  * send segment (e.g. FIN) to peer.  Socket will be really disconnected
498  * when peer sends FIN and acks ours.
499  *
500  * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
501  */
502 static int
503 tcp_usr_disconnect(struct socket *so)
504 {
505 	int s = splnet();
506 	int error = 0;
507 	struct inpcb *inp = sotoinpcb(so);
508 	struct tcpcb *tp;
509 
510 	COMMON_START();
511 	tp = tcp_disconnect(tp);
512 	COMMON_END(PRU_DISCONNECT);
513 }
514 
515 /*
516  * Accept a connection.  Essentially all the work is
517  * done at higher levels; just return the address
518  * of the peer, storing through addr.
519  */
520 static int
521 tcp_usr_accept(struct socket *so, struct sockaddr **nam)
522 {
523 	int s = splnet();
524 	int error = 0;
525 	struct inpcb *inp = sotoinpcb(so);
526 	struct tcpcb *tp = NULL;
527 	TCPDEBUG0;
528 
529 	if (so->so_state & SS_ISDISCONNECTED) {
530 		error = ECONNABORTED;
531 		goto out;
532 	}
533 	if (inp == 0) {
534 		splx(s);
535 		return (EINVAL);
536 	}
537 	tp = intotcpcb(inp);
538 	TCPDEBUG1();
539 	in_setpeeraddr(so, nam);
540 	COMMON_END(PRU_ACCEPT);
541 }
542 
543 #ifdef INET6
544 static int
545 tcp6_usr_accept(struct socket *so, struct sockaddr **nam)
546 {
547 	int s = splnet();
548 	int error = 0;
549 	struct inpcb *inp = sotoinpcb(so);
550 	struct tcpcb *tp = NULL;
551 	TCPDEBUG0;
552 
553 	if (so->so_state & SS_ISDISCONNECTED) {
554 		error = ECONNABORTED;
555 		goto out;
556 	}
557 	if (inp == 0) {
558 		splx(s);
559 		return (EINVAL);
560 	}
561 	tp = intotcpcb(inp);
562 	TCPDEBUG1();
563 	in6_mapped_peeraddr(so, nam);
564 	COMMON_END(PRU_ACCEPT);
565 }
566 #endif /* INET6 */
567 /*
568  * Mark the connection as being incapable of further output.
569  */
570 static int
571 tcp_usr_shutdown(struct socket *so)
572 {
573 	int s = splnet();
574 	int error = 0;
575 	struct inpcb *inp = sotoinpcb(so);
576 	struct tcpcb *tp;
577 
578 	COMMON_START();
579 	socantsendmore(so);
580 	tp = tcp_usrclosed(tp);
581 	if (tp)
582 		error = tcp_output(tp);
583 	COMMON_END(PRU_SHUTDOWN);
584 }
585 
586 /*
587  * After a receive, possibly send window update to peer.
588  */
589 static int
590 tcp_usr_rcvd(struct socket *so, int flags)
591 {
592 	int s = splnet();
593 	int error = 0;
594 	struct inpcb *inp = sotoinpcb(so);
595 	struct tcpcb *tp;
596 
597 	COMMON_START();
598 	tcp_output(tp);
599 	COMMON_END(PRU_RCVD);
600 }
601 
602 /*
603  * Do a send by putting data in output queue and updating urgent
604  * marker if URG set.  Possibly send more data.  Unlike the other
605  * pru_*() routines, the mbuf chains are our responsibility.  We
606  * must either enqueue them or free them.  The other pru_* routines
607  * generally are caller-frees.
608  */
609 static int
610 tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
611 	     struct sockaddr *nam, struct mbuf *control, struct thread *td)
612 {
613 	int s = splnet();
614 	int error = 0;
615 	struct inpcb *inp = sotoinpcb(so);
616 	struct tcpcb *tp;
617 #ifdef INET6
618 	int isipv6;
619 #endif
620 	TCPDEBUG0;
621 
622 	if (inp == NULL) {
623 		/*
624 		 * OOPS! we lost a race, the TCP session got reset after
625 		 * we checked SS_CANTSENDMORE, eg: while doing uiomove or a
626 		 * network interrupt in the non-splnet() section of sosend().
627 		 */
628 		if (m)
629 			m_freem(m);
630 		if (control)
631 			m_freem(control);
632 		error = ECONNRESET;	/* XXX EPIPE? */
633 		tp = NULL;
634 		TCPDEBUG1();
635 		goto out;
636 	}
637 #ifdef INET6
638 	isipv6 = nam && nam->sa_family == AF_INET6;
639 #endif /* INET6 */
640 	tp = intotcpcb(inp);
641 	TCPDEBUG1();
642 	if (control) {
643 		/* TCP doesn't do control messages (rights, creds, etc) */
644 		if (control->m_len) {
645 			m_freem(control);
646 			if (m)
647 				m_freem(m);
648 			error = EINVAL;
649 			goto out;
650 		}
651 		m_freem(control);	/* empty control, just free it */
652 	}
653 	if(!(flags & PRUS_OOB)) {
654 		sbappend(&so->so_snd, m);
655 		if (nam && tp->t_state < TCPS_SYN_SENT) {
656 			/*
657 			 * Do implied connect if not yet connected,
658 			 * initialize window to default value, and
659 			 * initialize maxseg/maxopd using peer's cached
660 			 * MSS.
661 			 */
662 #ifdef INET6
663 			if (isipv6)
664 				error = tcp6_connect(tp, nam, td);
665 			else
666 #endif /* INET6 */
667 			error = tcp_connect(tp, nam, td);
668 			if (error)
669 				goto out;
670 			tp->snd_wnd = TTCP_CLIENT_SND_WND;
671 			tcp_mss(tp, -1);
672 		}
673 
674 		if (flags & PRUS_EOF) {
675 			/*
676 			 * Close the send side of the connection after
677 			 * the data is sent.
678 			 */
679 			socantsendmore(so);
680 			tp = tcp_usrclosed(tp);
681 		}
682 		if (tp != NULL) {
683 			if (flags & PRUS_MORETOCOME)
684 				tp->t_flags |= TF_MORETOCOME;
685 			error = tcp_output(tp);
686 			if (flags & PRUS_MORETOCOME)
687 				tp->t_flags &= ~TF_MORETOCOME;
688 		}
689 	} else {
690 		if (sbspace(&so->so_snd) < -512) {
691 			m_freem(m);
692 			error = ENOBUFS;
693 			goto out;
694 		}
695 		/*
696 		 * According to RFC961 (Assigned Protocols),
697 		 * the urgent pointer points to the last octet
698 		 * of urgent data.  We continue, however,
699 		 * to consider it to indicate the first octet
700 		 * of data past the urgent section.
701 		 * Otherwise, snd_up should be one lower.
702 		 */
703 		sbappend(&so->so_snd, m);
704 		if (nam && tp->t_state < TCPS_SYN_SENT) {
705 			/*
706 			 * Do implied connect if not yet connected,
707 			 * initialize window to default value, and
708 			 * initialize maxseg/maxopd using peer's cached
709 			 * MSS.
710 			 */
711 #ifdef INET6
712 			if (isipv6)
713 				error = tcp6_connect(tp, nam, td);
714 			else
715 #endif /* INET6 */
716 			error = tcp_connect(tp, nam, td);
717 			if (error)
718 				goto out;
719 			tp->snd_wnd = TTCP_CLIENT_SND_WND;
720 			tcp_mss(tp, -1);
721 		}
722 		tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
723 		tp->t_flags |= TF_FORCE;
724 		error = tcp_output(tp);
725 		tp->t_flags &= ~TF_FORCE;
726 	}
727 	COMMON_END((flags & PRUS_OOB) ? PRU_SENDOOB :
728 		   ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
729 }
730 
731 /*
732  * Abort the TCP.
733  */
734 static int
735 tcp_usr_abort(struct socket *so)
736 {
737 	int s = splnet();
738 	int error = 0;
739 	struct inpcb *inp = sotoinpcb(so);
740 	struct tcpcb *tp;
741 
742 	COMMON_START();
743 	tp = tcp_drop(tp, ECONNABORTED);
744 	COMMON_END(PRU_ABORT);
745 }
746 
747 /*
748  * Receive out-of-band data.
749  */
750 static int
751 tcp_usr_rcvoob(struct socket *so, struct mbuf *m, int flags)
752 {
753 	int s = splnet();
754 	int error = 0;
755 	struct inpcb *inp = sotoinpcb(so);
756 	struct tcpcb *tp;
757 
758 	COMMON_START();
759 	if ((so->so_oobmark == 0 &&
760 	     (so->so_state & SS_RCVATMARK) == 0) ||
761 	    so->so_options & SO_OOBINLINE ||
762 	    tp->t_oobflags & TCPOOB_HADDATA) {
763 		error = EINVAL;
764 		goto out;
765 	}
766 	if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
767 		error = EWOULDBLOCK;
768 		goto out;
769 	}
770 	m->m_len = 1;
771 	*mtod(m, caddr_t) = tp->t_iobc;
772 	if ((flags & MSG_PEEK) == 0)
773 		tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
774 	COMMON_END(PRU_RCVOOB);
775 }
776 
777 /* xxx - should be const */
778 struct pr_usrreqs tcp_usrreqs = {
779 	tcp_usr_abort, tcp_usr_accept, tcp_usr_attach, tcp_usr_bind,
780 	tcp_usr_connect, pru_connect2_notsupp, in_control, tcp_usr_detach,
781 	tcp_usr_disconnect, tcp_usr_listen, in_setpeeraddr, tcp_usr_rcvd,
782 	tcp_usr_rcvoob, tcp_usr_send, pru_sense_null, tcp_usr_shutdown,
783 	in_setsockaddr, sosend, soreceive, sopoll
784 };
785 
786 #ifdef INET6
787 struct pr_usrreqs tcp6_usrreqs = {
788 	tcp_usr_abort, tcp6_usr_accept, tcp_usr_attach, tcp6_usr_bind,
789 	tcp6_usr_connect, pru_connect2_notsupp, in6_control, tcp_usr_detach,
790 	tcp_usr_disconnect, tcp6_usr_listen, in6_mapped_peeraddr, tcp_usr_rcvd,
791 	tcp_usr_rcvoob, tcp_usr_send, pru_sense_null, tcp_usr_shutdown,
792 	in6_mapped_sockaddr, sosend, soreceive, sopoll
793 };
794 #endif /* INET6 */
795 
796 static int
797 tcp_connect_oncpu(struct tcpcb *tp, struct sockaddr_in *sin,
798 		  struct sockaddr_in *if_sin)
799 {
800 	struct inpcb *inp = tp->t_inpcb, *oinp;
801 	struct socket *so = inp->inp_socket;
802 	struct tcpcb *otp;
803 	struct rmxp_tao *taop;
804 	struct rmxp_tao tao_noncached;
805 
806 	oinp = in_pcblookup_hash(&tcbinfo[mycpu->gd_cpuid],
807 	    sin->sin_addr, sin->sin_port,
808 	    inp->inp_laddr.s_addr != INADDR_ANY ?
809 	        inp->inp_laddr : if_sin->sin_addr,
810 	    inp->inp_lport, 0, NULL);
811 	if (oinp != NULL) {
812 		if (oinp != inp && (otp = intotcpcb(oinp)) != NULL &&
813 		    otp->t_state == TCPS_TIME_WAIT &&
814 		    (ticks - otp->t_starttime) < tcp_msl &&
815 		    (otp->t_flags & TF_RCVD_CC))
816 			(void) tcp_close(otp);
817 		else
818 			return (EADDRINUSE);
819 	}
820 	if (inp->inp_laddr.s_addr == INADDR_ANY)
821 		inp->inp_laddr = if_sin->sin_addr;
822 	inp->inp_faddr = sin->sin_addr;
823 	inp->inp_fport = sin->sin_port;
824 	inp->inp_cpcbinfo = &tcbinfo[mycpu->gd_cpuid];
825 	in_pcbinsconnhash(inp);
826 
827 	/* Compute window scaling to request.  */
828 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
829 	    (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
830 		tp->request_r_scale++;
831 
832 	soisconnecting(so);
833 	tcpstat.tcps_connattempt++;
834 	tp->t_state = TCPS_SYN_SENT;
835 	callout_reset(tp->tt_keep, tcp_keepinit, tcp_timer_keep, tp);
836 	tp->iss = tcp_new_isn(tp);
837 	tp->t_bw_rtseq = tp->iss;
838 	tcp_sendseqinit(tp);
839 
840 	/*
841 	 * Generate a CC value for this connection and
842 	 * check whether CC or CCnew should be used.
843 	 */
844 	if ((taop = tcp_gettaocache(&tp->t_inpcb->inp_inc)) == NULL) {
845 		taop = &tao_noncached;
846 		bzero(taop, sizeof(*taop));
847 	}
848 
849 	tp->cc_send = CC_INC(tcp_ccgen);
850 	if (taop->tao_ccsent != 0 &&
851 	    CC_GEQ(tp->cc_send, taop->tao_ccsent)) {
852 		taop->tao_ccsent = tp->cc_send;
853 	} else {
854 		taop->tao_ccsent = 0;
855 		tp->t_flags |= TF_SENDCCNEW;
856 	}
857 
858 	return (0);
859 }
860 
861 #ifdef SMP
862 
863 struct netmsg_tcp_connect {
864 	struct lwkt_msg		nm_lmsg;
865 	struct tcpcb		*nm_tp;
866 	struct sockaddr_in	*nm_sin;
867 	struct sockaddr_in	*nm_ifsin;
868 };
869 
870 static int
871 tcp_connect_handler(lwkt_msg_t lmsg)
872 {
873 	struct netmsg_tcp_connect *msg = (void *)lmsg;
874 	int error;
875 
876 	error = tcp_connect_oncpu(msg->nm_tp, msg->nm_sin, msg->nm_ifsin);
877 	lwkt_replymsg(lmsg, error);
878 	return(EASYNC);
879 }
880 
881 #endif
882 
883 /*
884  * Common subroutine to open a TCP connection to remote host specified
885  * by struct sockaddr_in in mbuf *nam.  Call in_pcbbind to assign a local
886  * port number if needed.  Call in_pcbladdr to do the routing and to choose
887  * a local host address (interface).  If there is an existing incarnation
888  * of the same connection in TIME-WAIT state and if the remote host was
889  * sending CC options and if the connection duration was < MSL, then
890  * truncate the previous TIME-WAIT state and proceed.
891  * Initialize connection parameters and enter SYN-SENT state.
892  */
893 static int
894 tcp_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
895 {
896 	struct inpcb *inp = tp->t_inpcb;
897 	struct sockaddr_in *sin = (struct sockaddr_in *)nam;
898 	struct sockaddr_in *if_sin;
899 	int error;
900 #ifdef SMP
901 	lwkt_port_t port;
902 #endif
903 
904 	if (inp->inp_lport == 0) {
905 		error = in_pcbbind(inp, (struct sockaddr *)NULL, td);
906 		if (error)
907 			return (error);
908 	}
909 
910 	/*
911 	 * Cannot simply call in_pcbconnect, because there might be an
912 	 * earlier incarnation of this same connection still in
913 	 * TIME_WAIT state, creating an ADDRINUSE error.
914 	 */
915 	error = in_pcbladdr(inp, nam, &if_sin);
916 	if (error)
917 		return (error);
918 
919 #ifdef SMP
920 	port = tcp_addrport(sin->sin_addr.s_addr, sin->sin_port,
921 	    inp->inp_laddr.s_addr ?
922 		inp->inp_laddr.s_addr : if_sin->sin_addr.s_addr,
923 	    inp->inp_lport);
924 
925 	if (port->mp_td != curthread) {
926 		struct netmsg_tcp_connect msg;
927 
928 		lwkt_initmsg(&msg.nm_lmsg, &curthread->td_msgport, 0,
929 		    lwkt_cmd_func(tcp_connect_handler), lwkt_cmd_op_none);
930 		msg.nm_tp = tp;
931 		msg.nm_sin = sin;
932 		msg.nm_ifsin = if_sin;
933 		error = lwkt_domsg(port, &msg.nm_lmsg);
934 	} else
935 #endif
936 		error = tcp_connect_oncpu(tp, sin, if_sin);
937 
938 	return (error);
939 }
940 
941 #ifdef INET6
942 static int
943 tcp6_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
944 {
945 	struct inpcb *inp = tp->t_inpcb, *oinp;
946 	struct socket *so = inp->inp_socket;
947 	struct tcpcb *otp;
948 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)nam;
949 	struct in6_addr *addr6;
950 	struct rmxp_tao *taop;
951 	struct rmxp_tao tao_noncached;
952 	int error;
953 
954 	if (inp->inp_lport == 0) {
955 		error = in6_pcbbind(inp, (struct sockaddr *)0, td);
956 		if (error)
957 			return error;
958 	}
959 
960 	/*
961 	 * Cannot simply call in_pcbconnect, because there might be an
962 	 * earlier incarnation of this same connection still in
963 	 * TIME_WAIT state, creating an ADDRINUSE error.
964 	 */
965 	error = in6_pcbladdr(inp, nam, &addr6);
966 	if (error)
967 		return error;
968 	oinp = in6_pcblookup_hash(inp->inp_cpcbinfo,
969 				  &sin6->sin6_addr, sin6->sin6_port,
970 				  IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) ?
971 				      addr6 : &inp->in6p_laddr,
972 				  inp->inp_lport,  0, NULL);
973 	if (oinp) {
974 		if (oinp != inp && (otp = intotcpcb(oinp)) != NULL &&
975 		    otp->t_state == TCPS_TIME_WAIT &&
976 		    (ticks - otp->t_starttime) < tcp_msl &&
977 		    (otp->t_flags & TF_RCVD_CC))
978 			otp = tcp_close(otp);
979 		else
980 			return (EADDRINUSE);
981 	}
982 	if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
983 		inp->in6p_laddr = *addr6;
984 	inp->in6p_faddr = sin6->sin6_addr;
985 	inp->inp_fport = sin6->sin6_port;
986 	if ((sin6->sin6_flowinfo & IPV6_FLOWINFO_MASK) != NULL)
987 		inp->in6p_flowinfo = sin6->sin6_flowinfo;
988 	in_pcbinsconnhash(inp);
989 
990 	/* Compute window scaling to request.  */
991 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
992 	    (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
993 		tp->request_r_scale++;
994 
995 	soisconnecting(so);
996 	tcpstat.tcps_connattempt++;
997 	tp->t_state = TCPS_SYN_SENT;
998 	callout_reset(tp->tt_keep, tcp_keepinit, tcp_timer_keep, tp);
999 	tp->iss = tcp_new_isn(tp);
1000 	tp->t_bw_rtseq = tp->iss;
1001 	tcp_sendseqinit(tp);
1002 
1003 	/*
1004 	 * Generate a CC value for this connection and
1005 	 * check whether CC or CCnew should be used.
1006 	 */
1007 	if ((taop = tcp_gettaocache(&tp->t_inpcb->inp_inc)) == NULL) {
1008 		taop = &tao_noncached;
1009 		bzero(taop, sizeof(*taop));
1010 	}
1011 
1012 	tp->cc_send = CC_INC(tcp_ccgen);
1013 	if (taop->tao_ccsent != 0 &&
1014 	    CC_GEQ(tp->cc_send, taop->tao_ccsent)) {
1015 		taop->tao_ccsent = tp->cc_send;
1016 	} else {
1017 		taop->tao_ccsent = 0;
1018 		tp->t_flags |= TF_SENDCCNEW;
1019 	}
1020 
1021 	return (0);
1022 }
1023 #endif /* INET6 */
1024 
1025 /*
1026  * The new sockopt interface makes it possible for us to block in the
1027  * copyin/out step (if we take a page fault).  Taking a page fault at
1028  * splnet() is probably a Bad Thing.  (Since sockets and pcbs both now
1029  * use TSM, there probably isn't any need for this function to run at
1030  * splnet() any more.  This needs more examination.)
1031  */
1032 int
1033 tcp_ctloutput(so, sopt)
1034 	struct socket *so;
1035 	struct sockopt *sopt;
1036 {
1037 	int	error, opt, optval, s;
1038 	struct	inpcb *inp;
1039 	struct	tcpcb *tp;
1040 
1041 	error = 0;
1042 	s = splnet();		/* XXX */
1043 	inp = sotoinpcb(so);
1044 	if (inp == NULL) {
1045 		splx(s);
1046 		return (ECONNRESET);
1047 	}
1048 	if (sopt->sopt_level != IPPROTO_TCP) {
1049 #ifdef INET6
1050 		if (INP_CHECK_SOCKAF(so, AF_INET6))
1051 			error = ip6_ctloutput(so, sopt);
1052 		else
1053 #endif /* INET6 */
1054 		error = ip_ctloutput(so, sopt);
1055 		splx(s);
1056 		return (error);
1057 	}
1058 	tp = intotcpcb(inp);
1059 
1060 	switch (sopt->sopt_dir) {
1061 	case SOPT_SET:
1062 		switch (sopt->sopt_name) {
1063 		case TCP_NODELAY:
1064 		case TCP_NOOPT:
1065 			error = sooptcopyin(sopt, &optval, sizeof optval,
1066 					    sizeof optval);
1067 			if (error)
1068 				break;
1069 
1070 			switch (sopt->sopt_name) {
1071 			case TCP_NODELAY:
1072 				opt = TF_NODELAY;
1073 				break;
1074 			case TCP_NOOPT:
1075 				opt = TF_NOOPT;
1076 				break;
1077 			default:
1078 				opt = 0; /* dead code to fool gcc */
1079 				break;
1080 			}
1081 
1082 			if (optval)
1083 				tp->t_flags |= opt;
1084 			else
1085 				tp->t_flags &= ~opt;
1086 			break;
1087 
1088 		case TCP_NOPUSH:
1089 			error = sooptcopyin(sopt, &optval, sizeof optval,
1090 					    sizeof optval);
1091 			if (error)
1092 				break;
1093 
1094 			if (optval)
1095 				tp->t_flags |= TF_NOPUSH;
1096 			else {
1097 				tp->t_flags &= ~TF_NOPUSH;
1098 				error = tcp_output(tp);
1099 			}
1100 			break;
1101 
1102 		case TCP_MAXSEG:
1103 			error = sooptcopyin(sopt, &optval, sizeof optval,
1104 					    sizeof optval);
1105 			if (error)
1106 				break;
1107 
1108 			if (optval > 0 && optval <= tp->t_maxseg)
1109 				tp->t_maxseg = optval;
1110 			else
1111 				error = EINVAL;
1112 			break;
1113 
1114 		default:
1115 			error = ENOPROTOOPT;
1116 			break;
1117 		}
1118 		break;
1119 
1120 	case SOPT_GET:
1121 		switch (sopt->sopt_name) {
1122 		case TCP_NODELAY:
1123 			optval = tp->t_flags & TF_NODELAY;
1124 			break;
1125 		case TCP_MAXSEG:
1126 			optval = tp->t_maxseg;
1127 			break;
1128 		case TCP_NOOPT:
1129 			optval = tp->t_flags & TF_NOOPT;
1130 			break;
1131 		case TCP_NOPUSH:
1132 			optval = tp->t_flags & TF_NOPUSH;
1133 			break;
1134 		default:
1135 			error = ENOPROTOOPT;
1136 			break;
1137 		}
1138 		if (error == 0)
1139 			error = sooptcopyout(sopt, &optval, sizeof optval);
1140 		break;
1141 	}
1142 	splx(s);
1143 	return (error);
1144 }
1145 
1146 /*
1147  * tcp_sendspace and tcp_recvspace are the default send and receive window
1148  * sizes, respectively.  These are obsolescent (this information should
1149  * be set by the route).
1150  */
1151 u_long	tcp_sendspace = 1024*32;
1152 SYSCTL_INT(_net_inet_tcp, TCPCTL_SENDSPACE, sendspace, CTLFLAG_RW,
1153     &tcp_sendspace , 0, "Maximum outgoing TCP datagram size");
1154 u_long	tcp_recvspace = 57344;	/* largest multiple of PAGE_SIZE < 64k */
1155 SYSCTL_INT(_net_inet_tcp, TCPCTL_RECVSPACE, recvspace, CTLFLAG_RW,
1156     &tcp_recvspace , 0, "Maximum incoming TCP datagram size");
1157 
1158 /*
1159  * Attach TCP protocol to socket, allocating
1160  * internet protocol control block, tcp control block,
1161  * bufer space, and entering LISTEN state if to accept connections.
1162  */
1163 static int
1164 tcp_attach(struct socket *so, struct pru_attach_info *ai)
1165 {
1166 	struct tcpcb *tp;
1167 	struct inpcb *inp;
1168 	int error;
1169 	int cpu;
1170 #ifdef INET6
1171 	int isipv6 = INP_CHECK_SOCKAF(so, AF_INET6) != NULL;
1172 #endif
1173 
1174 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
1175 		error = soreserve(so, tcp_sendspace, tcp_recvspace,
1176 				  ai->sb_rlimit);
1177 		if (error)
1178 			return (error);
1179 	}
1180 	cpu = mycpu->gd_cpuid;
1181 	error = in_pcballoc(so, &tcbinfo[cpu]);
1182 	if (error)
1183 		return (error);
1184 	inp = sotoinpcb(so);
1185 #ifdef INET6
1186 	if (isipv6) {
1187 		inp->inp_vflag |= INP_IPV6;
1188 		inp->in6p_hops = -1;	/* use kernel default */
1189 	}
1190 	else
1191 #endif
1192 	inp->inp_vflag |= INP_IPV4;
1193 	tp = tcp_newtcpcb(inp);
1194 	if (tp == 0) {
1195 		int nofd = so->so_state & SS_NOFDREF;	/* XXX */
1196 
1197 		so->so_state &= ~SS_NOFDREF;	/* don't free the socket yet */
1198 #ifdef INET6
1199 		if (isipv6)
1200 			in6_pcbdetach(inp);
1201 		else
1202 #endif
1203 		in_pcbdetach(inp);
1204 		so->so_state |= nofd;
1205 		return (ENOBUFS);
1206 	}
1207 	tp->t_state = TCPS_CLOSED;
1208 	return (0);
1209 }
1210 
1211 /*
1212  * Initiate (or continue) disconnect.
1213  * If embryonic state, just send reset (once).
1214  * If in ``let data drain'' option and linger null, just drop.
1215  * Otherwise (hard), mark socket disconnecting and drop
1216  * current input data; switch states based on user close, and
1217  * send segment to peer (with FIN).
1218  */
1219 static struct tcpcb *
1220 tcp_disconnect(tp)
1221 	struct tcpcb *tp;
1222 {
1223 	struct socket *so = tp->t_inpcb->inp_socket;
1224 
1225 	if (tp->t_state < TCPS_ESTABLISHED)
1226 		tp = tcp_close(tp);
1227 	else if ((so->so_options & SO_LINGER) && so->so_linger == 0)
1228 		tp = tcp_drop(tp, 0);
1229 	else {
1230 		soisdisconnecting(so);
1231 		sbflush(&so->so_rcv);
1232 		tp = tcp_usrclosed(tp);
1233 		if (tp)
1234 			(void) tcp_output(tp);
1235 	}
1236 	return (tp);
1237 }
1238 
1239 /*
1240  * User issued close, and wish to trail through shutdown states:
1241  * if never received SYN, just forget it.  If got a SYN from peer,
1242  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
1243  * If already got a FIN from peer, then almost done; go to LAST_ACK
1244  * state.  In all other cases, have already sent FIN to peer (e.g.
1245  * after PRU_SHUTDOWN), and just have to play tedious game waiting
1246  * for peer to send FIN or not respond to keep-alives, etc.
1247  * We can let the user exit from the close as soon as the FIN is acked.
1248  */
1249 static struct tcpcb *
1250 tcp_usrclosed(tp)
1251 	struct tcpcb *tp;
1252 {
1253 
1254 	switch (tp->t_state) {
1255 
1256 	case TCPS_CLOSED:
1257 	case TCPS_LISTEN:
1258 		tp->t_state = TCPS_CLOSED;
1259 		tp = tcp_close(tp);
1260 		break;
1261 
1262 	case TCPS_SYN_SENT:
1263 	case TCPS_SYN_RECEIVED:
1264 		tp->t_flags |= TF_NEEDFIN;
1265 		break;
1266 
1267 	case TCPS_ESTABLISHED:
1268 		tp->t_state = TCPS_FIN_WAIT_1;
1269 		break;
1270 
1271 	case TCPS_CLOSE_WAIT:
1272 		tp->t_state = TCPS_LAST_ACK;
1273 		break;
1274 	}
1275 	if (tp && tp->t_state >= TCPS_FIN_WAIT_2) {
1276 		soisdisconnected(tp->t_inpcb->inp_socket);
1277 		/* To prevent the connection hanging in FIN_WAIT_2 forever. */
1278 		if (tp->t_state == TCPS_FIN_WAIT_2)
1279 			callout_reset(tp->tt_2msl, tcp_maxidle,
1280 				      tcp_timer_2msl, tp);
1281 	}
1282 	return (tp);
1283 }
1284