xref: /dragonfly/sys/netinet/tcp_usrreq.c (revision dc71b7ab)
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) 1982, 1986, 1988, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. Neither the name of the University nor the names of its contributors
47  *    may be used to endorse or promote products derived from this software
48  *    without specific prior written permission.
49  *
50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60  * SUCH DAMAGE.
61  *
62  *	From: @(#)tcp_usrreq.c	8.2 (Berkeley) 1/3/94
63  * $FreeBSD: src/sys/netinet/tcp_usrreq.c,v 1.51.2.17 2002/10/11 11:46:44 ume Exp $
64  */
65 
66 #include "opt_ipsec.h"
67 #include "opt_inet.h"
68 #include "opt_inet6.h"
69 #include "opt_tcpdebug.h"
70 
71 #include <sys/param.h>
72 #include <sys/systm.h>
73 #include <sys/kernel.h>
74 #include <sys/malloc.h>
75 #include <sys/sysctl.h>
76 #include <sys/globaldata.h>
77 #include <sys/thread.h>
78 
79 #include <sys/mbuf.h>
80 #ifdef INET6
81 #include <sys/domain.h>
82 #endif /* INET6 */
83 #include <sys/socket.h>
84 #include <sys/socketvar.h>
85 #include <sys/socketops.h>
86 #include <sys/protosw.h>
87 
88 #include <sys/thread2.h>
89 #include <sys/msgport2.h>
90 #include <sys/socketvar2.h>
91 
92 #include <net/if.h>
93 #include <net/netisr.h>
94 #include <net/route.h>
95 
96 #include <net/netmsg2.h>
97 #include <net/netisr2.h>
98 
99 #include <netinet/in.h>
100 #include <netinet/in_systm.h>
101 #ifdef INET6
102 #include <netinet/ip6.h>
103 #endif
104 #include <netinet/in_pcb.h>
105 #ifdef INET6
106 #include <netinet6/in6_pcb.h>
107 #endif
108 #include <netinet/in_var.h>
109 #include <netinet/ip_var.h>
110 #ifdef INET6
111 #include <netinet6/ip6_var.h>
112 #include <netinet6/tcp6_var.h>
113 #endif
114 #include <netinet/tcp.h>
115 #include <netinet/tcp_fsm.h>
116 #include <netinet/tcp_seq.h>
117 #include <netinet/tcp_timer.h>
118 #include <netinet/tcp_timer2.h>
119 #include <netinet/tcp_var.h>
120 #include <netinet/tcpip.h>
121 #ifdef TCPDEBUG
122 #include <netinet/tcp_debug.h>
123 #endif
124 
125 #ifdef IPSEC
126 #include <netinet6/ipsec.h>
127 #endif /*IPSEC*/
128 
129 /*
130  * TCP protocol interface to socket abstraction.
131  */
132 extern	char *tcpstates[];	/* XXX ??? */
133 
134 static int	tcp_attach (struct socket *, struct pru_attach_info *);
135 static void	tcp_connect (netmsg_t msg);
136 #ifdef INET6
137 static void	tcp6_connect (netmsg_t msg);
138 static int	tcp6_connect_oncpu(struct tcpcb *tp, int flags,
139 				struct mbuf **mp,
140 				struct sockaddr_in6 *sin6,
141 				struct in6_addr *addr6);
142 #endif /* INET6 */
143 static struct tcpcb *
144 		tcp_disconnect (struct tcpcb *);
145 static struct tcpcb *
146 		tcp_usrclosed (struct tcpcb *);
147 
148 #ifdef TCPDEBUG
149 #define	TCPDEBUG0	int ostate = 0
150 #define	TCPDEBUG1()	ostate = tp ? tp->t_state : 0
151 #define	TCPDEBUG2(req)	if (tp && (so->so_options & SO_DEBUG)) \
152 				tcp_trace(TA_USER, ostate, tp, 0, 0, req)
153 #else
154 #define	TCPDEBUG0
155 #define	TCPDEBUG1()
156 #define	TCPDEBUG2(req)
157 #endif
158 
159 static int	tcp_lport_extension = 1;
160 SYSCTL_INT(_net_inet_tcp, OID_AUTO, lportext, CTLFLAG_RW,
161     &tcp_lport_extension, 0, "");
162 
163 /*
164  * For some ill optimized programs, which try to use TCP_NOPUSH
165  * to improve performance, will have small amount of data sits
166  * in the sending buffer.  These small amount of data will _not_
167  * be pushed into the network until more data are written into
168  * the socket or the socket write side is shutdown.
169  */
170 static int	tcp_disable_nopush = 1;
171 SYSCTL_INT(_net_inet_tcp, OID_AUTO, disable_nopush, CTLFLAG_RW,
172     &tcp_disable_nopush, 0, "TCP_NOPUSH socket option will have no effect");
173 
174 /*
175  * TCP attaches to socket via pru_attach(), reserving space,
176  * and an internet control block.  This is likely occuring on
177  * cpu0 and may have to move later when we bind/connect.
178  */
179 static void
180 tcp_usr_attach(netmsg_t msg)
181 {
182 	struct socket *so = msg->base.nm_so;
183 	struct pru_attach_info *ai = msg->attach.nm_ai;
184 	int error;
185 	struct inpcb *inp;
186 	struct tcpcb *tp = NULL;
187 	TCPDEBUG0;
188 
189 	soreference(so);
190 	inp = so->so_pcb;
191 	TCPDEBUG1();
192 	if (inp) {
193 		error = EISCONN;
194 		goto out;
195 	}
196 
197 	error = tcp_attach(so, ai);
198 	if (error)
199 		goto out;
200 
201 	if ((so->so_options & SO_LINGER) && so->so_linger == 0)
202 		so->so_linger = TCP_LINGERTIME;
203 	tp = sototcpcb(so);
204 out:
205 	sofree(so);		/* from ref above */
206 	TCPDEBUG2(PRU_ATTACH);
207 	lwkt_replymsg(&msg->lmsg, error);
208 }
209 
210 /*
211  * pru_detach() detaches the TCP protocol from the socket.
212  * If the protocol state is non-embryonic, then can't
213  * do this directly: have to initiate a pru_disconnect(),
214  * which may finish later; embryonic TCB's can just
215  * be discarded here.
216  */
217 static void
218 tcp_usr_detach(netmsg_t msg)
219 {
220 	struct socket *so = msg->base.nm_so;
221 	int error = 0;
222 	struct inpcb *inp;
223 	struct tcpcb *tp;
224 	TCPDEBUG0;
225 
226 	inp = so->so_pcb;
227 
228 	/*
229 	 * If the inp is already detached it may have been due to an async
230 	 * close.  Just return as if no error occured.
231 	 *
232 	 * It's possible for the tcpcb (tp) to disconnect from the inp due
233 	 * to tcp_drop()->tcp_close() being called.  This may occur *after*
234 	 * the detach message has been queued so we may find a NULL tp here.
235 	 */
236 	if (inp) {
237 		if ((tp = intotcpcb(inp)) != NULL) {
238 			TCPDEBUG1();
239 			tp = tcp_disconnect(tp);
240 			TCPDEBUG2(PRU_DETACH);
241 		}
242 	}
243 	lwkt_replymsg(&msg->lmsg, error);
244 }
245 
246 /*
247  * NOTE: ignore_error is non-zero for certain disconnection races
248  * which we want to silently allow, otherwise close() may return
249  * an unexpected error.
250  *
251  * NOTE: The variables (msg) and (tp) are assumed.
252  */
253 #define	COMMON_START(so, inp, ignore_error)			\
254 	TCPDEBUG0; 						\
255 								\
256 	inp = so->so_pcb; 					\
257 	do {							\
258 		 if (inp == NULL) {				\
259 			error = ignore_error ? 0 : EINVAL;	\
260 			tp = NULL;				\
261 			goto out;				\
262 		 }						\
263 		 tp = intotcpcb(inp);				\
264 		 TCPDEBUG1();					\
265 	} while(0)
266 
267 #define COMMON_END1(req, noreply)				\
268 	out: do {						\
269 		TCPDEBUG2(req);					\
270 		if (!(noreply))					\
271 			lwkt_replymsg(&msg->lmsg, error);	\
272 		return;						\
273 	} while(0)
274 
275 #define COMMON_END(req)		COMMON_END1((req), 0)
276 
277 /*
278  * Give the socket an address.
279  */
280 static void
281 tcp_usr_bind(netmsg_t msg)
282 {
283 	struct socket *so = msg->bind.base.nm_so;
284 	struct sockaddr *nam = msg->bind.nm_nam;
285 	struct thread *td = msg->bind.nm_td;
286 	int error = 0;
287 	struct inpcb *inp;
288 	struct tcpcb *tp;
289 	struct sockaddr_in *sinp;
290 
291 	COMMON_START(so, inp, 0);
292 
293 	/*
294 	 * Must check for multicast addresses and disallow binding
295 	 * to them.
296 	 */
297 	sinp = (struct sockaddr_in *)nam;
298 	if (sinp->sin_family == AF_INET &&
299 	    IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
300 		error = EAFNOSUPPORT;
301 		goto out;
302 	}
303 	error = in_pcbbind(inp, nam, td);
304 	if (error)
305 		goto out;
306 	COMMON_END(PRU_BIND);
307 
308 }
309 
310 #ifdef INET6
311 
312 static void
313 tcp6_usr_bind(netmsg_t msg)
314 {
315 	struct socket *so = msg->bind.base.nm_so;
316 	struct sockaddr *nam = msg->bind.nm_nam;
317 	struct thread *td = msg->bind.nm_td;
318 	int error = 0;
319 	struct inpcb *inp;
320 	struct tcpcb *tp;
321 	struct sockaddr_in6 *sin6p;
322 
323 	COMMON_START(so, inp, 0);
324 
325 	/*
326 	 * Must check for multicast addresses and disallow binding
327 	 * to them.
328 	 */
329 	sin6p = (struct sockaddr_in6 *)nam;
330 	if (sin6p->sin6_family == AF_INET6 &&
331 	    IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr)) {
332 		error = EAFNOSUPPORT;
333 		goto out;
334 	}
335 	inp->inp_vflag &= ~INP_IPV4;
336 	inp->inp_vflag |= INP_IPV6;
337 	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
338 		if (IN6_IS_ADDR_UNSPECIFIED(&sin6p->sin6_addr))
339 			inp->inp_vflag |= INP_IPV4;
340 		else if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
341 			struct sockaddr_in sin;
342 
343 			in6_sin6_2_sin(&sin, sin6p);
344 			inp->inp_vflag |= INP_IPV4;
345 			inp->inp_vflag &= ~INP_IPV6;
346 			error = in_pcbbind(inp, (struct sockaddr *)&sin, td);
347 			goto out;
348 		}
349 	}
350 	error = in6_pcbbind(inp, nam, td);
351 	if (error)
352 		goto out;
353 	COMMON_END(PRU_BIND);
354 }
355 #endif /* INET6 */
356 
357 struct netmsg_inswildcard {
358 	struct netmsg_base	base;
359 	struct inpcb		*nm_inp;
360 };
361 
362 static void
363 in_pcbinswildcardhash_handler(netmsg_t msg)
364 {
365 	struct netmsg_inswildcard *nm = (struct netmsg_inswildcard *)msg;
366 	int cpu = mycpuid, nextcpu;
367 
368 	in_pcbinswildcardhash_oncpu(nm->nm_inp, &tcbinfo[cpu]);
369 
370 	nextcpu = cpu + 1;
371 	if (nextcpu < ncpus2)
372 		lwkt_forwardmsg(netisr_cpuport(nextcpu), &nm->base.lmsg);
373 	else
374 		lwkt_replymsg(&nm->base.lmsg, 0);
375 }
376 
377 /*
378  * Prepare to accept connections.
379  */
380 static void
381 tcp_usr_listen(netmsg_t msg)
382 {
383 	struct socket *so = msg->listen.base.nm_so;
384 	struct thread *td = msg->listen.nm_td;
385 	int error = 0;
386 	struct inpcb *inp;
387 	struct tcpcb *tp;
388 	struct netmsg_inswildcard nm;
389 
390 	COMMON_START(so, inp, 0);
391 
392 	if (tp->t_flags & TF_LISTEN)
393 		goto out;
394 
395 	if (inp->inp_lport == 0) {
396 		error = in_pcbbind(inp, NULL, td);
397 		if (error)
398 			goto out;
399 	}
400 
401 	tp->t_state = TCPS_LISTEN;
402 	tp->t_flags |= TF_LISTEN;
403 	tp->tt_msg = NULL; /* Catch any invalid timer usage */
404 
405 	if (ncpus > 1) {
406 		/*
407 		 * We have to set the flag because we can't have other cpus
408 		 * messing with our inp's flags.
409 		 */
410 		KASSERT(!(inp->inp_flags & INP_CONNECTED),
411 			("already on connhash"));
412 		KASSERT(!(inp->inp_flags & INP_WILDCARD),
413 			("already on wildcardhash"));
414 		KASSERT(!(inp->inp_flags & INP_WILDCARD_MP),
415 			("already on MP wildcardhash"));
416 		inp->inp_flags |= INP_WILDCARD_MP;
417 
418 		KKASSERT(so->so_port == netisr_cpuport(0));
419 		KKASSERT(&curthread->td_msgport == netisr_cpuport(0));
420 		KKASSERT(inp->inp_pcbinfo == &tcbinfo[0]);
421 
422 		netmsg_init(&nm.base, NULL, &curthread->td_msgport,
423 			    MSGF_PRIORITY, in_pcbinswildcardhash_handler);
424 		nm.nm_inp = inp;
425 		lwkt_domsg(netisr_cpuport(1), &nm.base.lmsg, 0);
426 	}
427 	in_pcbinswildcardhash(inp);
428 	COMMON_END(PRU_LISTEN);
429 }
430 
431 #ifdef INET6
432 
433 static void
434 tcp6_usr_listen(netmsg_t msg)
435 {
436 	struct socket *so = msg->listen.base.nm_so;
437 	struct thread *td = msg->listen.nm_td;
438 	int error = 0;
439 	struct inpcb *inp;
440 	struct tcpcb *tp;
441 	struct netmsg_inswildcard nm;
442 
443 	COMMON_START(so, inp, 0);
444 
445 	if (tp->t_flags & TF_LISTEN)
446 		goto out;
447 
448 	if (inp->inp_lport == 0) {
449 		if (!(inp->inp_flags & IN6P_IPV6_V6ONLY))
450 			inp->inp_vflag |= INP_IPV4;
451 		else
452 			inp->inp_vflag &= ~INP_IPV4;
453 		error = in6_pcbbind(inp, NULL, td);
454 		if (error)
455 			goto out;
456 	}
457 
458 	tp->t_state = TCPS_LISTEN;
459 	tp->t_flags |= TF_LISTEN;
460 	tp->tt_msg = NULL; /* Catch any invalid timer usage */
461 
462 	if (ncpus > 1) {
463 		/*
464 		 * We have to set the flag because we can't have other cpus
465 		 * messing with our inp's flags.
466 		 */
467 		KASSERT(!(inp->inp_flags & INP_CONNECTED),
468 			("already on connhash"));
469 		KASSERT(!(inp->inp_flags & INP_WILDCARD),
470 			("already on wildcardhash"));
471 		KASSERT(!(inp->inp_flags & INP_WILDCARD_MP),
472 			("already on MP wildcardhash"));
473 		inp->inp_flags |= INP_WILDCARD_MP;
474 
475 		KKASSERT(so->so_port == netisr_cpuport(0));
476 		KKASSERT(&curthread->td_msgport == netisr_cpuport(0));
477 		KKASSERT(inp->inp_pcbinfo == &tcbinfo[0]);
478 
479 		netmsg_init(&nm.base, NULL, &curthread->td_msgport,
480 			    MSGF_PRIORITY, in_pcbinswildcardhash_handler);
481 		nm.nm_inp = inp;
482 		lwkt_domsg(netisr_cpuport(1), &nm.base.lmsg, 0);
483 	}
484 	in_pcbinswildcardhash(inp);
485 	COMMON_END(PRU_LISTEN);
486 }
487 #endif /* INET6 */
488 
489 /*
490  * Initiate connection to peer.
491  * Create a template for use in transmissions on this connection.
492  * Enter SYN_SENT state, and mark socket as connecting.
493  * Start keep-alive timer, and seed output sequence space.
494  * Send initial segment on connection.
495  */
496 static void
497 tcp_usr_connect(netmsg_t msg)
498 {
499 	struct socket *so = msg->connect.base.nm_so;
500 	struct sockaddr *nam = msg->connect.nm_nam;
501 	struct thread *td = msg->connect.nm_td;
502 	int error = 0;
503 	struct inpcb *inp;
504 	struct tcpcb *tp;
505 	struct sockaddr_in *sinp;
506 
507 	COMMON_START(so, inp, 0);
508 
509 	/*
510 	 * Must disallow TCP ``connections'' to multicast addresses.
511 	 */
512 	sinp = (struct sockaddr_in *)nam;
513 	if (sinp->sin_family == AF_INET
514 	    && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
515 		error = EAFNOSUPPORT;
516 		goto out;
517 	}
518 
519 	if (!prison_remote_ip(td, (struct sockaddr*)sinp)) {
520 		error = EAFNOSUPPORT; /* IPv6 only jail */
521 		goto out;
522 	}
523 
524 	tcp_connect(msg);
525 	/* msg is invalid now */
526 	return;
527 out:
528 	if (msg->connect.nm_m) {
529 		m_freem(msg->connect.nm_m);
530 		msg->connect.nm_m = NULL;
531 	}
532 	lwkt_replymsg(&msg->lmsg, error);
533 }
534 
535 #ifdef INET6
536 
537 static void
538 tcp6_usr_connect(netmsg_t msg)
539 {
540 	struct socket *so = msg->connect.base.nm_so;
541 	struct sockaddr *nam = msg->connect.nm_nam;
542 	struct thread *td = msg->connect.nm_td;
543 	int error = 0;
544 	struct inpcb *inp;
545 	struct tcpcb *tp;
546 	struct sockaddr_in6 *sin6p;
547 
548 	COMMON_START(so, inp, 0);
549 
550 	/*
551 	 * Must disallow TCP ``connections'' to multicast addresses.
552 	 */
553 	sin6p = (struct sockaddr_in6 *)nam;
554 	if (sin6p->sin6_family == AF_INET6
555 	    && IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr)) {
556 		error = EAFNOSUPPORT;
557 		goto out;
558 	}
559 
560 	if (!prison_remote_ip(td, nam)) {
561 		error = EAFNOSUPPORT; /* IPv4 only jail */
562 		goto out;
563 	}
564 
565 	if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
566 		struct sockaddr_in *sinp;
567 
568 		if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
569 			error = EINVAL;
570 			goto out;
571 		}
572 		sinp = kmalloc(sizeof(*sinp), M_LWKTMSG, M_INTWAIT);
573 		in6_sin6_2_sin(sinp, sin6p);
574 		inp->inp_vflag |= INP_IPV4;
575 		inp->inp_vflag &= ~INP_IPV6;
576 		msg->connect.nm_nam = (struct sockaddr *)sinp;
577 		msg->connect.nm_reconnect |= NMSG_RECONNECT_NAMALLOC;
578 		tcp_connect(msg);
579 		/* msg is invalid now */
580 		return;
581 	}
582 	inp->inp_vflag &= ~INP_IPV4;
583 	inp->inp_vflag |= INP_IPV6;
584 	inp->inp_inc.inc_isipv6 = 1;
585 
586 	msg->connect.nm_reconnect |= NMSG_RECONNECT_FALLBACK;
587 	tcp6_connect(msg);
588 	/* msg is invalid now */
589 	return;
590 out:
591 	if (msg->connect.nm_m) {
592 		m_freem(msg->connect.nm_m);
593 		msg->connect.nm_m = NULL;
594 	}
595 	lwkt_replymsg(&msg->lmsg, error);
596 }
597 
598 #endif /* INET6 */
599 
600 /*
601  * Initiate disconnect from peer.
602  * If connection never passed embryonic stage, just drop;
603  * else if don't need to let data drain, then can just drop anyways,
604  * else have to begin TCP shutdown process: mark socket disconnecting,
605  * drain unread data, state switch to reflect user close, and
606  * send segment (e.g. FIN) to peer.  Socket will be really disconnected
607  * when peer sends FIN and acks ours.
608  *
609  * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
610  */
611 static void
612 tcp_usr_disconnect(netmsg_t msg)
613 {
614 	struct socket *so = msg->disconnect.base.nm_so;
615 	int error = 0;
616 	struct inpcb *inp;
617 	struct tcpcb *tp;
618 
619 	COMMON_START(so, inp, 1);
620 	tp = tcp_disconnect(tp);
621 	COMMON_END(PRU_DISCONNECT);
622 }
623 
624 /*
625  * Accept a connection.  Essentially all the work is
626  * done at higher levels; just return the address
627  * of the peer, storing through addr.
628  */
629 static void
630 tcp_usr_accept(netmsg_t msg)
631 {
632 	struct socket *so = msg->accept.base.nm_so;
633 	struct sockaddr **nam = msg->accept.nm_nam;
634 	int error = 0;
635 	struct inpcb *inp;
636 	struct tcpcb *tp = NULL;
637 	TCPDEBUG0;
638 
639 	inp = so->so_pcb;
640 	if (so->so_state & SS_ISDISCONNECTED) {
641 		error = ECONNABORTED;
642 		goto out;
643 	}
644 	if (inp == 0) {
645 		error = EINVAL;
646 		goto out;
647 	}
648 
649 	tp = intotcpcb(inp);
650 	TCPDEBUG1();
651 	in_setpeeraddr(so, nam);
652 	COMMON_END(PRU_ACCEPT);
653 }
654 
655 #ifdef INET6
656 static void
657 tcp6_usr_accept(netmsg_t msg)
658 {
659 	struct socket *so = msg->accept.base.nm_so;
660 	struct sockaddr **nam = msg->accept.nm_nam;
661 	int error = 0;
662 	struct inpcb *inp;
663 	struct tcpcb *tp = NULL;
664 	TCPDEBUG0;
665 
666 	inp = so->so_pcb;
667 
668 	if (so->so_state & SS_ISDISCONNECTED) {
669 		error = ECONNABORTED;
670 		goto out;
671 	}
672 	if (inp == 0) {
673 		error = EINVAL;
674 		goto out;
675 	}
676 	tp = intotcpcb(inp);
677 	TCPDEBUG1();
678 	in6_mapped_peeraddr(so, nam);
679 	COMMON_END(PRU_ACCEPT);
680 }
681 #endif /* INET6 */
682 /*
683  * Mark the connection as being incapable of further output.
684  */
685 static void
686 tcp_usr_shutdown(netmsg_t msg)
687 {
688 	struct socket *so = msg->shutdown.base.nm_so;
689 	int error = 0;
690 	struct inpcb *inp;
691 	struct tcpcb *tp;
692 
693 	COMMON_START(so, inp, 0);
694 	socantsendmore(so);
695 	tp = tcp_usrclosed(tp);
696 	if (tp)
697 		error = tcp_output(tp);
698 	COMMON_END(PRU_SHUTDOWN);
699 }
700 
701 /*
702  * After a receive, possibly send window update to peer.
703  */
704 static void
705 tcp_usr_rcvd(netmsg_t msg)
706 {
707 	struct socket *so = msg->rcvd.base.nm_so;
708 	int error = 0, noreply = 0;
709 	struct inpcb *inp;
710 	struct tcpcb *tp;
711 
712 	COMMON_START(so, inp, 0);
713 
714 	if (msg->rcvd.nm_pru_flags & PRUR_ASYNC) {
715 		noreply = 1;
716 		so_async_rcvd_reply(so);
717 	}
718 	tcp_output(tp);
719 
720 	COMMON_END1(PRU_RCVD, noreply);
721 }
722 
723 /*
724  * Do a send by putting data in output queue and updating urgent
725  * marker if URG set.  Possibly send more data.  Unlike the other
726  * pru_*() routines, the mbuf chains are our responsibility.  We
727  * must either enqueue them or free them.  The other pru_* routines
728  * generally are caller-frees.
729  */
730 static void
731 tcp_usr_send(netmsg_t msg)
732 {
733 	struct socket *so = msg->send.base.nm_so;
734 	int flags = msg->send.nm_flags;
735 	struct mbuf *m = msg->send.nm_m;
736 	int error = 0;
737 	struct inpcb *inp;
738 	struct tcpcb *tp;
739 	TCPDEBUG0;
740 
741 	KKASSERT(msg->send.nm_control == NULL);
742 	KKASSERT(msg->send.nm_addr == NULL);
743 	KKASSERT((flags & PRUS_FREEADDR) == 0);
744 
745 	inp = so->so_pcb;
746 
747 	if (inp == NULL) {
748 		/*
749 		 * OOPS! we lost a race, the TCP session got reset after
750 		 * we checked SS_CANTSENDMORE, eg: while doing uiomove or a
751 		 * network interrupt in the non-critical section of sosend().
752 		 */
753 		m_freem(m);
754 		error = ECONNRESET;	/* XXX EPIPE? */
755 		tp = NULL;
756 		TCPDEBUG1();
757 		goto out;
758 	}
759 	tp = intotcpcb(inp);
760 	TCPDEBUG1();
761 
762 #ifdef foo
763 	/*
764 	 * This is no longer necessary, since:
765 	 * - sosendtcp() has already checked it for us
766 	 * - It does not work with asynchronized send
767 	 */
768 
769 	/*
770 	 * Don't let too much OOB data build up
771 	 */
772 	if (flags & PRUS_OOB) {
773 		if (ssb_space(&so->so_snd) < -512) {
774 			m_freem(m);
775 			error = ENOBUFS;
776 			goto out;
777 		}
778 	}
779 #endif
780 
781 	/*
782 	 * Pump the data into the socket.
783 	 */
784 	if (m)
785 		ssb_appendstream(&so->so_snd, m);
786 	if (flags & PRUS_OOB) {
787 		/*
788 		 * According to RFC961 (Assigned Protocols),
789 		 * the urgent pointer points to the last octet
790 		 * of urgent data.  We continue, however,
791 		 * to consider it to indicate the first octet
792 		 * of data past the urgent section.
793 		 * Otherwise, snd_up should be one lower.
794 		 */
795 		tp->snd_up = tp->snd_una + so->so_snd.ssb_cc;
796 		tp->t_flags |= TF_FORCE;
797 		error = tcp_output(tp);
798 		tp->t_flags &= ~TF_FORCE;
799 	} else {
800 		if (flags & PRUS_EOF) {
801 			/*
802 			 * Close the send side of the connection after
803 			 * the data is sent.
804 			 */
805 			socantsendmore(so);
806 			tp = tcp_usrclosed(tp);
807 		}
808 		if (tp != NULL && !tcp_output_pending(tp)) {
809 			if (flags & PRUS_MORETOCOME)
810 				tp->t_flags |= TF_MORETOCOME;
811 			error = tcp_output_fair(tp);
812 			if (flags & PRUS_MORETOCOME)
813 				tp->t_flags &= ~TF_MORETOCOME;
814 		}
815 	}
816 	COMMON_END1((flags & PRUS_OOB) ? PRU_SENDOOB :
817 		   ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND),
818 		   (flags & PRUS_NOREPLY));
819 }
820 
821 /*
822  * NOTE: (so) is referenced from soabort*() and netmsg_pru_abort()
823  *	 will sofree() it when we return.
824  */
825 static void
826 tcp_usr_abort(netmsg_t msg)
827 {
828 	struct socket *so = msg->abort.base.nm_so;
829 	int error = 0;
830 	struct inpcb *inp;
831 	struct tcpcb *tp;
832 
833 	COMMON_START(so, inp, 1);
834 	tp = tcp_drop(tp, ECONNABORTED);
835 	COMMON_END(PRU_ABORT);
836 }
837 
838 /*
839  * Receive out-of-band data.
840  */
841 static void
842 tcp_usr_rcvoob(netmsg_t msg)
843 {
844 	struct socket *so = msg->rcvoob.base.nm_so;
845 	struct mbuf *m = msg->rcvoob.nm_m;
846 	int flags = msg->rcvoob.nm_flags;
847 	int error = 0;
848 	struct inpcb *inp;
849 	struct tcpcb *tp;
850 
851 	COMMON_START(so, inp, 0);
852 	if ((so->so_oobmark == 0 &&
853 	     (so->so_state & SS_RCVATMARK) == 0) ||
854 	    so->so_options & SO_OOBINLINE ||
855 	    tp->t_oobflags & TCPOOB_HADDATA) {
856 		error = EINVAL;
857 		goto out;
858 	}
859 	if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
860 		error = EWOULDBLOCK;
861 		goto out;
862 	}
863 	m->m_len = 1;
864 	*mtod(m, caddr_t) = tp->t_iobc;
865 	if ((flags & MSG_PEEK) == 0)
866 		tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
867 	COMMON_END(PRU_RCVOOB);
868 }
869 
870 static void
871 tcp_usr_savefaddr(struct socket *so, const struct sockaddr *faddr)
872 {
873 	in_savefaddr(so, faddr);
874 }
875 
876 #ifdef INET6
877 static void
878 tcp6_usr_savefaddr(struct socket *so, const struct sockaddr *faddr)
879 {
880 	in6_mapped_savefaddr(so, faddr);
881 }
882 #endif
883 
884 /* xxx - should be const */
885 struct pr_usrreqs tcp_usrreqs = {
886 	.pru_abort = tcp_usr_abort,
887 	.pru_accept = tcp_usr_accept,
888 	.pru_attach = tcp_usr_attach,
889 	.pru_bind = tcp_usr_bind,
890 	.pru_connect = tcp_usr_connect,
891 	.pru_connect2 = pr_generic_notsupp,
892 	.pru_control = in_control_dispatch,
893 	.pru_detach = tcp_usr_detach,
894 	.pru_disconnect = tcp_usr_disconnect,
895 	.pru_listen = tcp_usr_listen,
896 	.pru_peeraddr = in_setpeeraddr_dispatch,
897 	.pru_rcvd = tcp_usr_rcvd,
898 	.pru_rcvoob = tcp_usr_rcvoob,
899 	.pru_send = tcp_usr_send,
900 	.pru_sense = pru_sense_null,
901 	.pru_shutdown = tcp_usr_shutdown,
902 	.pru_sockaddr = in_setsockaddr_dispatch,
903 	.pru_sosend = sosendtcp,
904 	.pru_soreceive = sorecvtcp,
905 	.pru_savefaddr = tcp_usr_savefaddr
906 };
907 
908 #ifdef INET6
909 struct pr_usrreqs tcp6_usrreqs = {
910 	.pru_abort = tcp_usr_abort,
911 	.pru_accept = tcp6_usr_accept,
912 	.pru_attach = tcp_usr_attach,
913 	.pru_bind = tcp6_usr_bind,
914 	.pru_connect = tcp6_usr_connect,
915 	.pru_connect2 = pr_generic_notsupp,
916 	.pru_control = in6_control_dispatch,
917 	.pru_detach = tcp_usr_detach,
918 	.pru_disconnect = tcp_usr_disconnect,
919 	.pru_listen = tcp6_usr_listen,
920 	.pru_peeraddr = in6_mapped_peeraddr_dispatch,
921 	.pru_rcvd = tcp_usr_rcvd,
922 	.pru_rcvoob = tcp_usr_rcvoob,
923 	.pru_send = tcp_usr_send,
924 	.pru_sense = pru_sense_null,
925 	.pru_shutdown = tcp_usr_shutdown,
926 	.pru_sockaddr = in6_mapped_sockaddr_dispatch,
927 	.pru_sosend = sosendtcp,
928 	.pru_soreceive = sorecvtcp,
929 	.pru_savefaddr = tcp6_usr_savefaddr
930 };
931 #endif /* INET6 */
932 
933 static int
934 tcp_connect_oncpu(struct tcpcb *tp, int flags, struct mbuf *m,
935 		  struct sockaddr_in *sin, struct sockaddr_in *if_sin)
936 {
937 	struct inpcb *inp = tp->t_inpcb, *oinp;
938 	struct socket *so = inp->inp_socket;
939 	struct route *ro = &inp->inp_route;
940 
941 	oinp = in_pcblookup_hash(&tcbinfo[mycpu->gd_cpuid],
942 				 sin->sin_addr, sin->sin_port,
943 				 (inp->inp_laddr.s_addr != INADDR_ANY ?
944 				  inp->inp_laddr : if_sin->sin_addr),
945 				inp->inp_lport, 0, NULL);
946 	if (oinp != NULL) {
947 		m_freem(m);
948 		return (EADDRINUSE);
949 	}
950 	if (inp->inp_laddr.s_addr == INADDR_ANY)
951 		inp->inp_laddr = if_sin->sin_addr;
952 	inp->inp_faddr = sin->sin_addr;
953 	inp->inp_fport = sin->sin_port;
954 	inp->inp_cpcbinfo = &tcbinfo[mycpu->gd_cpuid];
955 	in_pcbinsconnhash(inp);
956 
957 	/*
958 	 * We are now on the inpcb's owner CPU, if the cached route was
959 	 * freed because the rtentry's owner CPU is not the current CPU
960 	 * (e.g. in tcp_connect()), then we try to reallocate it here with
961 	 * the hope that a rtentry may be cloned from a RTF_PRCLONING
962 	 * rtentry.
963 	 */
964 	if (!(inp->inp_socket->so_options & SO_DONTROUTE) && /*XXX*/
965 	    ro->ro_rt == NULL) {
966 		bzero(&ro->ro_dst, sizeof(struct sockaddr_in));
967 		ro->ro_dst.sa_family = AF_INET;
968 		ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
969 		((struct sockaddr_in *)&ro->ro_dst)->sin_addr =
970 			sin->sin_addr;
971 		rtalloc(ro);
972 	}
973 
974 	/*
975 	 * Now that no more errors can occur, change the protocol processing
976 	 * port to the current thread (which is the correct thread).
977 	 *
978 	 * Create TCP timer message now; we are on the tcpcb's owner
979 	 * CPU/thread.
980 	 */
981 	tcp_create_timermsg(tp, &curthread->td_msgport);
982 
983 	/*
984 	 * Compute window scaling to request.  Use a larger scaling then
985 	 * needed for the initial receive buffer in case the receive buffer
986 	 * gets expanded.
987 	 */
988 	if (tp->request_r_scale < TCP_MIN_WINSHIFT)
989 		tp->request_r_scale = TCP_MIN_WINSHIFT;
990 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
991 	       (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.ssb_hiwat
992 	) {
993 		tp->request_r_scale++;
994 	}
995 
996 	soisconnecting(so);
997 	tcpstat.tcps_connattempt++;
998 	tp->t_state = TCPS_SYN_SENT;
999 	tcp_callout_reset(tp, tp->tt_keep, tp->t_keepinit, tcp_timer_keep);
1000 	tp->iss = tcp_new_isn(tp);
1001 	tcp_sendseqinit(tp);
1002 	if (m) {
1003 		ssb_appendstream(&so->so_snd, m);
1004 		m = NULL;
1005 		if (flags & PRUS_OOB)
1006 			tp->snd_up = tp->snd_una + so->so_snd.ssb_cc;
1007 	}
1008 
1009 	/*
1010 	 * Close the send side of the connection after
1011 	 * the data is sent if flagged.
1012 	 */
1013 	if ((flags & (PRUS_OOB|PRUS_EOF)) == PRUS_EOF) {
1014 		socantsendmore(so);
1015 		tp = tcp_usrclosed(tp);
1016 	}
1017 	return (tcp_output(tp));
1018 }
1019 
1020 /*
1021  * Common subroutine to open a TCP connection to remote host specified
1022  * by struct sockaddr_in in mbuf *nam.  Call in_pcbbind to assign a local
1023  * port number if needed.  Call in_pcbladdr to do the routing and to choose
1024  * a local host address (interface).
1025  * Initialize connection parameters and enter SYN-SENT state.
1026  */
1027 static void
1028 tcp_connect(netmsg_t msg)
1029 {
1030 	struct socket *so = msg->connect.base.nm_so;
1031 	struct sockaddr *nam = msg->connect.nm_nam;
1032 	struct thread *td = msg->connect.nm_td;
1033 	struct sockaddr_in *sin = (struct sockaddr_in *)nam;
1034 	struct sockaddr_in *if_sin;
1035 	struct inpcb *inp;
1036 	struct tcpcb *tp;
1037 	int error, calc_laddr = 1;
1038 	lwkt_port_t port;
1039 
1040 	COMMON_START(so, inp, 0);
1041 
1042 	/*
1043 	 * Reconnect our pcb if we have to
1044 	 */
1045 	if (msg->connect.nm_reconnect & NMSG_RECONNECT_RECONNECT) {
1046 		msg->connect.nm_reconnect &= ~NMSG_RECONNECT_RECONNECT;
1047 		in_pcblink(so->so_pcb, &tcbinfo[mycpu->gd_cpuid]);
1048 	}
1049 
1050 	/*
1051 	 * Bind if we have to
1052 	 */
1053 	if (inp->inp_lport == 0) {
1054 		if (tcp_lport_extension) {
1055 			KKASSERT(inp->inp_laddr.s_addr == INADDR_ANY);
1056 
1057 			error = in_pcbladdr(inp, nam, &if_sin, td);
1058 			if (error)
1059 				goto out;
1060 			inp->inp_laddr.s_addr = if_sin->sin_addr.s_addr;
1061 
1062 			error = in_pcbconn_bind(inp, nam, td);
1063 			if (error)
1064 				goto out;
1065 
1066 			calc_laddr = 0;
1067 		} else {
1068 			error = in_pcbbind(inp, NULL, td);
1069 			if (error)
1070 				goto out;
1071 		}
1072 	}
1073 
1074 	if (calc_laddr) {
1075 		/*
1076 		 * Calculate the correct protocol processing thread.  The
1077 		 * connect operation must run there.  Set the forwarding
1078 		 * port before we forward the message or it will get bounced
1079 		 * right back to us.
1080 		 */
1081 		error = in_pcbladdr(inp, nam, &if_sin, td);
1082 		if (error)
1083 			goto out;
1084 	}
1085 	KKASSERT(inp->inp_socket == so);
1086 
1087 	port = tcp_addrport(sin->sin_addr.s_addr, sin->sin_port,
1088 			    (inp->inp_laddr.s_addr ?
1089 			     inp->inp_laddr.s_addr : if_sin->sin_addr.s_addr),
1090 			    inp->inp_lport);
1091 
1092 	if (port != &curthread->td_msgport) {
1093 		struct route *ro = &inp->inp_route;
1094 
1095 		/*
1096 		 * in_pcbladdr() may have allocated a route entry for us
1097 		 * on the current CPU, but we need a route entry on the
1098 		 * inpcb's owner CPU, so free it here.
1099 		 */
1100 		if (ro->ro_rt != NULL)
1101 			RTFREE(ro->ro_rt);
1102 		bzero(ro, sizeof(*ro));
1103 
1104 		/*
1105 		 * We are moving the protocol processing port the socket
1106 		 * is on, we have to unlink here and re-link on the
1107 		 * target cpu.
1108 		 */
1109 		in_pcbunlink(so->so_pcb, &tcbinfo[mycpu->gd_cpuid]);
1110 		sosetport(so, port);
1111 		msg->connect.nm_reconnect |= NMSG_RECONNECT_RECONNECT;
1112 		msg->connect.base.nm_dispatch = tcp_connect;
1113 
1114 		lwkt_forwardmsg(port, &msg->connect.base.lmsg);
1115 		/* msg invalid now */
1116 		return;
1117 	}
1118 	error = tcp_connect_oncpu(tp, msg->connect.nm_flags,
1119 				  msg->connect.nm_m, sin, if_sin);
1120 	msg->connect.nm_m = NULL;
1121 out:
1122 	if (msg->connect.nm_m) {
1123 		m_freem(msg->connect.nm_m);
1124 		msg->connect.nm_m = NULL;
1125 	}
1126 	if (msg->connect.nm_reconnect & NMSG_RECONNECT_NAMALLOC) {
1127 		kfree(msg->connect.nm_nam, M_LWKTMSG);
1128 		msg->connect.nm_nam = NULL;
1129 	}
1130 	lwkt_replymsg(&msg->connect.base.lmsg, error);
1131 	/* msg invalid now */
1132 }
1133 
1134 #ifdef INET6
1135 
1136 static void
1137 tcp6_connect(netmsg_t msg)
1138 {
1139 	struct tcpcb *tp;
1140 	struct socket *so = msg->connect.base.nm_so;
1141 	struct sockaddr *nam = msg->connect.nm_nam;
1142 	struct thread *td = msg->connect.nm_td;
1143 	struct inpcb *inp;
1144 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)nam;
1145 	struct in6_addr *addr6;
1146 	lwkt_port_t port;
1147 	int error;
1148 
1149 	COMMON_START(so, inp, 0);
1150 
1151 	/*
1152 	 * Reconnect our pcb if we have to
1153 	 */
1154 	if (msg->connect.nm_reconnect & NMSG_RECONNECT_RECONNECT) {
1155 		msg->connect.nm_reconnect &= ~NMSG_RECONNECT_RECONNECT;
1156 		in_pcblink(so->so_pcb, &tcbinfo[mycpu->gd_cpuid]);
1157 	}
1158 
1159 	/*
1160 	 * Bind if we have to
1161 	 */
1162 	if (inp->inp_lport == 0) {
1163 		error = in6_pcbbind(inp, NULL, td);
1164 		if (error)
1165 			goto out;
1166 	}
1167 
1168 	/*
1169 	 * Cannot simply call in_pcbconnect, because there might be an
1170 	 * earlier incarnation of this same connection still in
1171 	 * TIME_WAIT state, creating an ADDRINUSE error.
1172 	 */
1173 	error = in6_pcbladdr(inp, nam, &addr6, td);
1174 	if (error)
1175 		goto out;
1176 
1177 	port = tcp6_addrport();	/* XXX hack for now, always cpu0 */
1178 
1179 	if (port != &curthread->td_msgport) {
1180 		struct route *ro = &inp->inp_route;
1181 
1182 		/*
1183 		 * in_pcbladdr() may have allocated a route entry for us
1184 		 * on the current CPU, but we need a route entry on the
1185 		 * inpcb's owner CPU, so free it here.
1186 		 */
1187 		if (ro->ro_rt != NULL)
1188 			RTFREE(ro->ro_rt);
1189 		bzero(ro, sizeof(*ro));
1190 
1191 		in_pcbunlink(so->so_pcb, &tcbinfo[mycpu->gd_cpuid]);
1192 		sosetport(so, port);
1193 		msg->connect.nm_reconnect |= NMSG_RECONNECT_RECONNECT;
1194 		msg->connect.base.nm_dispatch = tcp6_connect;
1195 
1196 		lwkt_forwardmsg(port, &msg->connect.base.lmsg);
1197 		/* msg invalid now */
1198 		return;
1199 	}
1200 	error = tcp6_connect_oncpu(tp, msg->connect.nm_flags,
1201 				   &msg->connect.nm_m, sin6, addr6);
1202 	/* nm_m may still be intact */
1203 out:
1204 	if (error && (msg->connect.nm_reconnect & NMSG_RECONNECT_FALLBACK)) {
1205 		tcp_connect(msg);
1206 		/* msg invalid now */
1207 	} else {
1208 		if (msg->connect.nm_m) {
1209 			m_freem(msg->connect.nm_m);
1210 			msg->connect.nm_m = NULL;
1211 		}
1212 		if (msg->connect.nm_reconnect & NMSG_RECONNECT_NAMALLOC) {
1213 			kfree(msg->connect.nm_nam, M_LWKTMSG);
1214 			msg->connect.nm_nam = NULL;
1215 		}
1216 		lwkt_replymsg(&msg->connect.base.lmsg, error);
1217 		/* msg invalid now */
1218 	}
1219 }
1220 
1221 static int
1222 tcp6_connect_oncpu(struct tcpcb *tp, int flags, struct mbuf **mp,
1223 		   struct sockaddr_in6 *sin6, struct in6_addr *addr6)
1224 {
1225 	struct mbuf *m = *mp;
1226 	struct inpcb *inp = tp->t_inpcb;
1227 	struct socket *so = inp->inp_socket;
1228 	struct inpcb *oinp;
1229 
1230 	/*
1231 	 * Cannot simply call in_pcbconnect, because there might be an
1232 	 * earlier incarnation of this same connection still in
1233 	 * TIME_WAIT state, creating an ADDRINUSE error.
1234 	 */
1235 	oinp = in6_pcblookup_hash(inp->inp_cpcbinfo,
1236 				  &sin6->sin6_addr, sin6->sin6_port,
1237 				  (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) ?
1238 				      addr6 : &inp->in6p_laddr),
1239 				  inp->inp_lport,  0, NULL);
1240 	if (oinp)
1241 		return (EADDRINUSE);
1242 
1243 	if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
1244 		inp->in6p_laddr = *addr6;
1245 	inp->in6p_faddr = sin6->sin6_addr;
1246 	inp->inp_fport = sin6->sin6_port;
1247 	if ((sin6->sin6_flowinfo & IPV6_FLOWINFO_MASK) != 0)
1248 		inp->in6p_flowinfo = sin6->sin6_flowinfo;
1249 	in_pcbinsconnhash(inp);
1250 
1251 	/*
1252 	 * Now that no more errors can occur, change the protocol processing
1253 	 * port to the current thread (which is the correct thread).
1254 	 *
1255 	 * Create TCP timer message now; we are on the tcpcb's owner
1256 	 * CPU/thread.
1257 	 */
1258 	tcp_create_timermsg(tp, &curthread->td_msgport);
1259 
1260 	/* Compute window scaling to request.  */
1261 	if (tp->request_r_scale < TCP_MIN_WINSHIFT)
1262 		tp->request_r_scale = TCP_MIN_WINSHIFT;
1263 	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1264 	    (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.ssb_hiwat) {
1265 		tp->request_r_scale++;
1266 	}
1267 
1268 	soisconnecting(so);
1269 	tcpstat.tcps_connattempt++;
1270 	tp->t_state = TCPS_SYN_SENT;
1271 	tcp_callout_reset(tp, tp->tt_keep, tp->t_keepinit, tcp_timer_keep);
1272 	tp->iss = tcp_new_isn(tp);
1273 	tcp_sendseqinit(tp);
1274 	if (m) {
1275 		ssb_appendstream(&so->so_snd, m);
1276 		*mp = NULL;
1277 		if (flags & PRUS_OOB)
1278 			tp->snd_up = tp->snd_una + so->so_snd.ssb_cc;
1279 	}
1280 
1281 	/*
1282 	 * Close the send side of the connection after
1283 	 * the data is sent if flagged.
1284 	 */
1285 	if ((flags & (PRUS_OOB|PRUS_EOF)) == PRUS_EOF) {
1286 		socantsendmore(so);
1287 		tp = tcp_usrclosed(tp);
1288 	}
1289 	return (tcp_output(tp));
1290 }
1291 
1292 #endif /* INET6 */
1293 
1294 /*
1295  * The new sockopt interface makes it possible for us to block in the
1296  * copyin/out step (if we take a page fault).  Taking a page fault while
1297  * in a critical section is probably a Bad Thing.  (Since sockets and pcbs
1298  * both now use TSM, there probably isn't any need for this function to
1299  * run in a critical section any more.  This needs more examination.)
1300  */
1301 void
1302 tcp_ctloutput(netmsg_t msg)
1303 {
1304 	struct socket *so = msg->base.nm_so;
1305 	struct sockopt *sopt = msg->ctloutput.nm_sopt;
1306 	int	error, opt, optval, opthz;
1307 	struct	inpcb *inp;
1308 	struct	tcpcb *tp;
1309 
1310 	error = 0;
1311 	inp = so->so_pcb;
1312 	if (inp == NULL) {
1313 		error = ECONNRESET;
1314 		goto done;
1315 	}
1316 
1317 	if (sopt->sopt_level != IPPROTO_TCP) {
1318 #ifdef INET6
1319 		if (INP_CHECK_SOCKAF(so, AF_INET6))
1320 			ip6_ctloutput_dispatch(msg);
1321 		else
1322 #endif /* INET6 */
1323 		ip_ctloutput(msg);
1324 		/* msg invalid now */
1325 		return;
1326 	}
1327 	tp = intotcpcb(inp);
1328 
1329 	switch (sopt->sopt_dir) {
1330 	case SOPT_SET:
1331 		error = soopt_to_kbuf(sopt, &optval, sizeof optval,
1332 				      sizeof optval);
1333 		if (error)
1334 			break;
1335 		switch (sopt->sopt_name) {
1336 		case TCP_FASTKEEP:
1337 			if (optval > 0)
1338 				tp->t_keepidle = tp->t_keepintvl;
1339 			else
1340 				tp->t_keepidle = tcp_keepidle;
1341 			tcp_timer_keep_activity(tp, 0);
1342 			break;
1343 #ifdef TCP_SIGNATURE
1344 		case TCP_SIGNATURE_ENABLE:
1345 			if (tp->t_state == TCPS_CLOSED) {
1346 				/*
1347 				 * This is the only safe state that this
1348 				 * option could be changed.  Some segments
1349 				 * could already have been sent in other
1350 				 * states.
1351 				 */
1352 				if (optval > 0)
1353 					tp->t_flags |= TF_SIGNATURE;
1354 				else
1355 					tp->t_flags &= ~TF_SIGNATURE;
1356 			} else {
1357 				error = EOPNOTSUPP;
1358 			}
1359 			break;
1360 #endif /* TCP_SIGNATURE */
1361 		case TCP_NODELAY:
1362 		case TCP_NOOPT:
1363 			switch (sopt->sopt_name) {
1364 			case TCP_NODELAY:
1365 				opt = TF_NODELAY;
1366 				break;
1367 			case TCP_NOOPT:
1368 				opt = TF_NOOPT;
1369 				break;
1370 			default:
1371 				opt = 0; /* dead code to fool gcc */
1372 				break;
1373 			}
1374 
1375 			if (optval)
1376 				tp->t_flags |= opt;
1377 			else
1378 				tp->t_flags &= ~opt;
1379 			break;
1380 
1381 		case TCP_NOPUSH:
1382 			if (tcp_disable_nopush)
1383 				break;
1384 			if (optval)
1385 				tp->t_flags |= TF_NOPUSH;
1386 			else {
1387 				tp->t_flags &= ~TF_NOPUSH;
1388 				error = tcp_output(tp);
1389 			}
1390 			break;
1391 
1392 		case TCP_MAXSEG:
1393 			/*
1394 			 * Must be between 0 and maxseg.  If the requested
1395 			 * maxseg is too small to satisfy the desired minmss,
1396 			 * pump it up (silently so sysctl modifications of
1397 			 * minmss do not create unexpected program failures).
1398 			 * Handle degenerate cases.
1399 			 */
1400 			if (optval > 0 && optval <= tp->t_maxseg) {
1401 				if (optval + 40 < tcp_minmss) {
1402 					optval = tcp_minmss - 40;
1403 					if (optval < 0)
1404 						optval = 1;
1405 				}
1406 				tp->t_maxseg = optval;
1407 			} else {
1408 				error = EINVAL;
1409 			}
1410 			break;
1411 
1412 		case TCP_KEEPINIT:
1413 			opthz = ((int64_t)optval * hz) / 1000;
1414 			if (opthz >= 1)
1415 				tp->t_keepinit = opthz;
1416 			else
1417 				error = EINVAL;
1418 			break;
1419 
1420 		case TCP_KEEPIDLE:
1421 			opthz = ((int64_t)optval * hz) / 1000;
1422 			if (opthz >= 1) {
1423 				tp->t_keepidle = opthz;
1424 				tcp_timer_keep_activity(tp, 0);
1425 			} else {
1426 				error = EINVAL;
1427 			}
1428 			break;
1429 
1430 		case TCP_KEEPINTVL:
1431 			opthz = ((int64_t)optval * hz) / 1000;
1432 			if (opthz >= 1) {
1433 				tp->t_keepintvl = opthz;
1434 				tp->t_maxidle = tp->t_keepintvl * tp->t_keepcnt;
1435 			} else {
1436 				error = EINVAL;
1437 			}
1438 			break;
1439 
1440 		case TCP_KEEPCNT:
1441 			if (optval > 0) {
1442 				tp->t_keepcnt = optval;
1443 				tp->t_maxidle = tp->t_keepintvl * tp->t_keepcnt;
1444 			} else {
1445 				error = EINVAL;
1446 			}
1447 			break;
1448 
1449 		default:
1450 			error = ENOPROTOOPT;
1451 			break;
1452 		}
1453 		break;
1454 
1455 	case SOPT_GET:
1456 		switch (sopt->sopt_name) {
1457 #ifdef TCP_SIGNATURE
1458 		case TCP_SIGNATURE_ENABLE:
1459 			optval = (tp->t_flags & TF_SIGNATURE) ? 1 : 0;
1460 			break;
1461 #endif /* TCP_SIGNATURE */
1462 		case TCP_NODELAY:
1463 			optval = tp->t_flags & TF_NODELAY;
1464 			break;
1465 		case TCP_MAXSEG:
1466 			optval = tp->t_maxseg;
1467 			break;
1468 		case TCP_NOOPT:
1469 			optval = tp->t_flags & TF_NOOPT;
1470 			break;
1471 		case TCP_NOPUSH:
1472 			optval = tp->t_flags & TF_NOPUSH;
1473 			break;
1474 		case TCP_KEEPINIT:
1475 			optval = ((int64_t)tp->t_keepinit * 1000) / hz;
1476 			break;
1477 		case TCP_KEEPIDLE:
1478 			optval = ((int64_t)tp->t_keepidle * 1000) / hz;
1479 			break;
1480 		case TCP_KEEPINTVL:
1481 			optval = ((int64_t)tp->t_keepintvl * 1000) / hz;
1482 			break;
1483 		case TCP_KEEPCNT:
1484 			optval = tp->t_keepcnt;
1485 			break;
1486 		default:
1487 			error = ENOPROTOOPT;
1488 			break;
1489 		}
1490 		if (error == 0)
1491 			soopt_from_kbuf(sopt, &optval, sizeof optval);
1492 		break;
1493 	}
1494 done:
1495 	lwkt_replymsg(&msg->lmsg, error);
1496 }
1497 
1498 /*
1499  * tcp_sendspace and tcp_recvspace are the default send and receive window
1500  * sizes, respectively.  These are obsolescent (this information should
1501  * be set by the route).
1502  *
1503  * Use a default that does not require tcp window scaling to be turned
1504  * on.  Individual programs or the administrator can increase the default.
1505  */
1506 u_long	tcp_sendspace = 57344;	/* largest multiple of PAGE_SIZE < 64k */
1507 SYSCTL_INT(_net_inet_tcp, TCPCTL_SENDSPACE, sendspace, CTLFLAG_RW,
1508     &tcp_sendspace , 0, "Maximum outgoing TCP datagram size");
1509 u_long	tcp_recvspace = 57344;	/* largest multiple of PAGE_SIZE < 64k */
1510 SYSCTL_INT(_net_inet_tcp, TCPCTL_RECVSPACE, recvspace, CTLFLAG_RW,
1511     &tcp_recvspace , 0, "Maximum incoming TCP datagram size");
1512 
1513 /*
1514  * Attach TCP protocol to socket, allocating internet protocol control
1515  * block, tcp control block, bufer space, and entering LISTEN state
1516  * if to accept connections.
1517  */
1518 static int
1519 tcp_attach(struct socket *so, struct pru_attach_info *ai)
1520 {
1521 	struct tcpcb *tp;
1522 	struct inpcb *inp;
1523 	int error;
1524 	int cpu;
1525 #ifdef INET6
1526 	int isipv6 = INP_CHECK_SOCKAF(so, AF_INET6) != 0;
1527 #endif
1528 
1529 	if (so->so_snd.ssb_hiwat == 0 || so->so_rcv.ssb_hiwat == 0) {
1530 		lwkt_gettoken(&so->so_rcv.ssb_token);
1531 		error = soreserve(so, tcp_sendspace, tcp_recvspace,
1532 				  ai->sb_rlimit);
1533 		lwkt_reltoken(&so->so_rcv.ssb_token);
1534 		if (error)
1535 			return (error);
1536 	}
1537 	atomic_set_int(&so->so_rcv.ssb_flags, SSB_AUTOSIZE);
1538 	atomic_set_int(&so->so_snd.ssb_flags, SSB_AUTOSIZE);
1539 	cpu = mycpu->gd_cpuid;
1540 
1541 	/*
1542 	 * Set the default port for protocol processing. This will likely
1543 	 * change when we connect.
1544 	 */
1545 	error = in_pcballoc(so, &tcbinfo[cpu]);
1546 	if (error)
1547 		return (error);
1548 	inp = so->so_pcb;
1549 #ifdef INET6
1550 	if (isipv6) {
1551 		inp->inp_vflag |= INP_IPV6;
1552 		inp->in6p_hops = -1;	/* use kernel default */
1553 	}
1554 	else
1555 #endif
1556 	inp->inp_vflag |= INP_IPV4;
1557 	tp = tcp_newtcpcb(inp);
1558 	if (tp == NULL) {
1559 		/*
1560 		 * Make sure the socket is destroyed by the pcbdetach.
1561 		 */
1562 		soreference(so);
1563 #ifdef INET6
1564 		if (isipv6)
1565 			in6_pcbdetach(inp);
1566 		else
1567 #endif
1568 		in_pcbdetach(inp);
1569 		sofree(so);	/* from ref above */
1570 		return (ENOBUFS);
1571 	}
1572 	tp->t_state = TCPS_CLOSED;
1573 	/* Keep a reference for asynchronized pru_rcvd */
1574 	soreference(so);
1575 	return (0);
1576 }
1577 
1578 /*
1579  * Initiate (or continue) disconnect.
1580  * If embryonic state, just send reset (once).
1581  * If in ``let data drain'' option and linger null, just drop.
1582  * Otherwise (hard), mark socket disconnecting and drop
1583  * current input data; switch states based on user close, and
1584  * send segment to peer (with FIN).
1585  */
1586 static struct tcpcb *
1587 tcp_disconnect(struct tcpcb *tp)
1588 {
1589 	struct socket *so = tp->t_inpcb->inp_socket;
1590 
1591 	if (tp->t_state < TCPS_ESTABLISHED) {
1592 		tp = tcp_close(tp);
1593 	} else if ((so->so_options & SO_LINGER) && so->so_linger == 0) {
1594 		tp = tcp_drop(tp, 0);
1595 	} else {
1596 		lwkt_gettoken(&so->so_rcv.ssb_token);
1597 		soisdisconnecting(so);
1598 		sbflush(&so->so_rcv.sb);
1599 		tp = tcp_usrclosed(tp);
1600 		if (tp)
1601 			tcp_output(tp);
1602 		lwkt_reltoken(&so->so_rcv.ssb_token);
1603 	}
1604 	return (tp);
1605 }
1606 
1607 /*
1608  * User issued close, and wish to trail through shutdown states:
1609  * if never received SYN, just forget it.  If got a SYN from peer,
1610  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
1611  * If already got a FIN from peer, then almost done; go to LAST_ACK
1612  * state.  In all other cases, have already sent FIN to peer (e.g.
1613  * after PRU_SHUTDOWN), and just have to play tedious game waiting
1614  * for peer to send FIN or not respond to keep-alives, etc.
1615  * We can let the user exit from the close as soon as the FIN is acked.
1616  */
1617 static struct tcpcb *
1618 tcp_usrclosed(struct tcpcb *tp)
1619 {
1620 
1621 	switch (tp->t_state) {
1622 
1623 	case TCPS_CLOSED:
1624 	case TCPS_LISTEN:
1625 		tp->t_state = TCPS_CLOSED;
1626 		tp = tcp_close(tp);
1627 		break;
1628 
1629 	case TCPS_SYN_SENT:
1630 	case TCPS_SYN_RECEIVED:
1631 		tp->t_flags |= TF_NEEDFIN;
1632 		break;
1633 
1634 	case TCPS_ESTABLISHED:
1635 		tp->t_state = TCPS_FIN_WAIT_1;
1636 		break;
1637 
1638 	case TCPS_CLOSE_WAIT:
1639 		tp->t_state = TCPS_LAST_ACK;
1640 		break;
1641 	}
1642 	if (tp && tp->t_state >= TCPS_FIN_WAIT_2) {
1643 		soisdisconnected(tp->t_inpcb->inp_socket);
1644 		/* To prevent the connection hanging in FIN_WAIT_2 forever. */
1645 		if (tp->t_state == TCPS_FIN_WAIT_2) {
1646 			tcp_callout_reset(tp, tp->tt_2msl, tp->t_maxidle,
1647 			    tcp_timer_2msl);
1648 		}
1649 	}
1650 	return (tp);
1651 }
1652