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tcp_usrreq.c revision 1.42.8.1
      1 /*	$NetBSD: tcp_usrreq.c,v 1.42.8.1 1999/12/27 18:36:20 wrstuden Exp $	*/
      2 
      3 /*
      4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the project nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 /*-
     33  * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
     34  * All rights reserved.
     35  *
     36  * This code is derived from software contributed to The NetBSD Foundation
     37  * by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation
     38  * Facility, NASA Ames Research Center.
     39  *
     40  * Redistribution and use in source and binary forms, with or without
     41  * modification, are permitted provided that the following conditions
     42  * are met:
     43  * 1. Redistributions of source code must retain the above copyright
     44  *    notice, this list of conditions and the following disclaimer.
     45  * 2. Redistributions in binary form must reproduce the above copyright
     46  *    notice, this list of conditions and the following disclaimer in the
     47  *    documentation and/or other materials provided with the distribution.
     48  * 3. All advertising materials mentioning features or use of this software
     49  *    must display the following acknowledgement:
     50  *	This product includes software developed by the NetBSD
     51  *	Foundation, Inc. and its contributors.
     52  * 4. Neither the name of The NetBSD Foundation nor the names of its
     53  *    contributors may be used to endorse or promote products derived
     54  *    from this software without specific prior written permission.
     55  *
     56  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     57  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     58  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     59  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     60  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     61  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     62  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     63  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     64  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     65  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     66  * POSSIBILITY OF SUCH DAMAGE.
     67  */
     68 
     69 /*
     70  * Copyright (c) 1982, 1986, 1988, 1993, 1995
     71  *	The Regents of the University of California.  All rights reserved.
     72  *
     73  * Redistribution and use in source and binary forms, with or without
     74  * modification, are permitted provided that the following conditions
     75  * are met:
     76  * 1. Redistributions of source code must retain the above copyright
     77  *    notice, this list of conditions and the following disclaimer.
     78  * 2. Redistributions in binary form must reproduce the above copyright
     79  *    notice, this list of conditions and the following disclaimer in the
     80  *    documentation and/or other materials provided with the distribution.
     81  * 3. All advertising materials mentioning features or use of this software
     82  *    must display the following acknowledgement:
     83  *	This product includes software developed by the University of
     84  *	California, Berkeley and its contributors.
     85  * 4. Neither the name of the University nor the names of its contributors
     86  *    may be used to endorse or promote products derived from this software
     87  *    without specific prior written permission.
     88  *
     89  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     90  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     91  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     92  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     93  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     94  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     95  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     96  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     97  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     98  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     99  * SUCH DAMAGE.
    100  *
    101  *	@(#)tcp_usrreq.c	8.5 (Berkeley) 6/21/95
    102  */
    103 
    104 #include "opt_inet.h"
    105 #include "opt_ipsec.h"
    106 
    107 #include <sys/param.h>
    108 #include <sys/systm.h>
    109 #include <sys/kernel.h>
    110 #include <sys/malloc.h>
    111 #include <sys/mbuf.h>
    112 #include <sys/socket.h>
    113 #include <sys/socketvar.h>
    114 #include <sys/protosw.h>
    115 #include <sys/errno.h>
    116 #include <sys/stat.h>
    117 #include <sys/proc.h>
    118 #include <sys/ucred.h>
    119 #include <sys/domain.h>
    120 
    121 #include <vm/vm.h>
    122 #include <sys/sysctl.h>
    123 
    124 #include <net/if.h>
    125 #include <net/route.h>
    126 
    127 #include <netinet/in.h>
    128 #include <netinet/in_systm.h>
    129 #include <netinet/in_var.h>
    130 #include <netinet/ip.h>
    131 #include <netinet/in_pcb.h>
    132 #include <netinet/ip_var.h>
    133 
    134 #ifdef INET6
    135 #ifndef INET
    136 #include <netinet/in.h>
    137 #endif
    138 #include <netinet/ip6.h>
    139 #include <netinet6/in6_pcb.h>
    140 #include <netinet6/ip6_var.h>
    141 #endif
    142 
    143 #include <netinet/tcp.h>
    144 #include <netinet/tcp_fsm.h>
    145 #include <netinet/tcp_seq.h>
    146 #include <netinet/tcp_timer.h>
    147 #include <netinet/tcp_var.h>
    148 #include <netinet/tcpip.h>
    149 #include <netinet/tcp_debug.h>
    150 
    151 #include "opt_tcp_recvspace.h"
    152 #include "opt_tcp_sendspace.h"
    153 
    154 #ifdef IPSEC
    155 #include <netinet6/ipsec.h>
    156 #endif /*IPSEC*/
    157 
    158 /*
    159  * TCP protocol interface to socket abstraction.
    160  */
    161 extern	char *tcpstates[];
    162 
    163 /*
    164  * Process a TCP user request for TCP tb.  If this is a send request
    165  * then m is the mbuf chain of send data.  If this is a timer expiration
    166  * (called from the software clock routine), then timertype tells which timer.
    167  */
    168 /*ARGSUSED*/
    169 int
    170 tcp_usrreq(so, req, m, nam, control, p)
    171 	struct socket *so;
    172 	int req;
    173 	struct mbuf *m, *nam, *control;
    174 	struct proc *p;
    175 {
    176 	register struct inpcb *inp;
    177 #ifdef INET6
    178 	register struct in6pcb *in6p;
    179 #endif
    180 	register struct tcpcb *tp = NULL;
    181 	int s;
    182 	int error = 0;
    183 	int ostate;
    184 	int family;	/* family of the socket */
    185 
    186 	family = so->so_proto->pr_domain->dom_family;
    187 
    188 	if (req == PRU_CONTROL) {
    189 		switch (family) {
    190 		case PF_INET:
    191 			return (in_control(so, (long)m, (caddr_t)nam,
    192 			    (struct ifnet *)control, p));
    193 #ifdef INET6
    194 		case PF_INET6:
    195 			return (in6_control(so, (long)m, (caddr_t)nam,
    196 			    (struct ifnet *)control, p));
    197 #endif
    198 		default:
    199 			return EAFNOSUPPORT;
    200 		}
    201 	}
    202 
    203 	s = splsoftnet();
    204 	switch (family) {
    205 	case PF_INET:
    206 		inp = sotoinpcb(so);
    207 #ifdef INET6
    208 		in6p = NULL;
    209 #endif
    210 		break;
    211 #ifdef INET6
    212 	case PF_INET6:
    213 		inp = NULL;
    214 		in6p = sotoin6pcb(so);
    215 		break;
    216 #endif
    217 	default:
    218 		splx(s);
    219 		return EAFNOSUPPORT;
    220 	}
    221 
    222 #ifdef DIAGNOSTIC
    223 	if (req != PRU_SEND && req != PRU_SENDOOB && control)
    224 		panic("tcp_usrreq: unexpected control mbuf");
    225 #endif
    226 	/*
    227 	 * When a TCP is attached to a socket, then there will be
    228 	 * a (struct inpcb) pointed at by the socket, and this
    229 	 * structure will point at a subsidary (struct tcpcb).
    230 	 */
    231 #ifndef INET6
    232 	if (inp == 0 && req != PRU_ATTACH)
    233 #else
    234 	if ((inp == 0 && in6p == 0) && req != PRU_ATTACH)
    235 #endif
    236 	{
    237 		error = EINVAL;
    238 		goto release;
    239 	}
    240 	if (inp) {
    241 		tp = intotcpcb(inp);
    242 		/* WHAT IF TP IS 0? */
    243 #ifdef KPROF
    244 		tcp_acounts[tp->t_state][req]++;
    245 #endif
    246 		ostate = tp->t_state;
    247 	}
    248 #ifdef INET6
    249 	else if (in6p) {
    250 		tp = in6totcpcb(in6p);
    251 		/* WHAT IF TP IS 0? */
    252 #ifdef KPROF
    253 		tcp_acounts[tp->t_state][req]++;
    254 #endif
    255 		ostate = tp->t_state;
    256 	}
    257 #endif
    258 	else
    259 		ostate = 0;
    260 
    261 	switch (req) {
    262 
    263 	/*
    264 	 * TCP attaches to socket via PRU_ATTACH, reserving space,
    265 	 * and an internet control block.
    266 	 */
    267 	case PRU_ATTACH:
    268 #ifndef INET6
    269 		if (inp != 0)
    270 #else
    271 		if (inp != 0 || in6p != 0)
    272 #endif
    273 		{
    274 			error = EISCONN;
    275 			break;
    276 		}
    277 		error = tcp_attach(so);
    278 		if (error)
    279 			break;
    280 		if ((so->so_options & SO_LINGER) && so->so_linger == 0)
    281 			so->so_linger = TCP_LINGERTIME;
    282 		tp = sototcpcb(so);
    283 		break;
    284 
    285 	/*
    286 	 * PRU_DETACH detaches the TCP protocol from the socket.
    287 	 */
    288 	case PRU_DETACH:
    289 		tp = tcp_disconnect(tp);
    290 		break;
    291 
    292 	/*
    293 	 * Give the socket an address.
    294 	 */
    295 	case PRU_BIND:
    296 		switch (family) {
    297 		case PF_INET:
    298 			error = in_pcbbind(inp, nam, p);
    299 			break;
    300 #ifdef INET6
    301 		case PF_INET6:
    302 			error = in6_pcbbind(in6p, nam /*, p*/ );
    303 			/* mapped addr case */
    304 			if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_laddr))
    305 				tp->t_family = AF_INET;
    306 			break;
    307 #endif
    308 		}
    309 		break;
    310 
    311 	/*
    312 	 * Prepare to accept connections.
    313 	 */
    314 	case PRU_LISTEN:
    315 		if (inp && inp->inp_lport == 0) {
    316 			error = in_pcbbind(inp, (struct mbuf *)0,
    317 			    (struct proc *)0);
    318 			if (error)
    319 				break;
    320 		}
    321 #ifdef INET6
    322 		else if (in6p && in6p->in6p_lport == 0) {
    323 			error = in6_pcbbind(in6p, (struct mbuf *)0 /*,
    324 			    (struct proc *)0 */ );
    325 			if (error)
    326 				break;
    327 		}
    328 #endif
    329 		tp->t_state = TCPS_LISTEN;
    330 		break;
    331 
    332 	/*
    333 	 * Initiate connection to peer.
    334 	 * Create a template for use in transmissions on this connection.
    335 	 * Enter SYN_SENT state, and mark socket as connecting.
    336 	 * Start keep-alive timer, and seed output sequence space.
    337 	 * Send initial segment on connection.
    338 	 */
    339 	case PRU_CONNECT:
    340 		if (inp) {
    341 			if (inp->inp_lport == 0) {
    342 				error = in_pcbbind(inp, (struct mbuf *)0,
    343 				    (struct proc *)0);
    344 				if (error)
    345 					break;
    346 			}
    347 			error = in_pcbconnect(inp, nam);
    348 		}
    349 #ifdef INET6
    350 		else if (in6p) {
    351 			if (in6p->in6p_lport == 0) {
    352 				error = in6_pcbbind(in6p, (struct mbuf *)0 /*,
    353 				    (struct proc *)0 */ );
    354 				if (error)
    355 					break;
    356 			}
    357 			error = in6_pcbconnect(in6p, nam);
    358 			/* mapped addr case */
    359 			if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr))
    360 				tp->t_family = AF_INET;
    361 		}
    362 #endif
    363 		if (error)
    364 			break;
    365 		tp->t_template = tcp_template(tp);
    366 		if (tp->t_template == 0) {
    367 			if (inp)
    368 				in_pcbdisconnect(inp);
    369 #ifdef INET6
    370 			else if (in6p)
    371 				in6_pcbdisconnect(in6p);
    372 #endif
    373 			error = ENOBUFS;
    374 			break;
    375 		}
    376 		/* Compute window scaling to request.  */
    377 		while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
    378 		    (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
    379 			tp->request_r_scale++;
    380 		soisconnecting(so);
    381 		tcpstat.tcps_connattempt++;
    382 		tp->t_state = TCPS_SYN_SENT;
    383 		TCP_TIMER_ARM(tp, TCPT_KEEP, TCPTV_KEEP_INIT);
    384 		tp->iss = tcp_new_iss(tp, sizeof(struct tcpcb), 0);
    385 		tcp_sendseqinit(tp);
    386 		error = tcp_output(tp);
    387 		break;
    388 
    389 	/*
    390 	 * Create a TCP connection between two sockets.
    391 	 */
    392 	case PRU_CONNECT2:
    393 		error = EOPNOTSUPP;
    394 		break;
    395 
    396 	/*
    397 	 * Initiate disconnect from peer.
    398 	 * If connection never passed embryonic stage, just drop;
    399 	 * else if don't need to let data drain, then can just drop anyways,
    400 	 * else have to begin TCP shutdown process: mark socket disconnecting,
    401 	 * drain unread data, state switch to reflect user close, and
    402 	 * send segment (e.g. FIN) to peer.  Socket will be really disconnected
    403 	 * when peer sends FIN and acks ours.
    404 	 *
    405 	 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
    406 	 */
    407 	case PRU_DISCONNECT:
    408 		tp = tcp_disconnect(tp);
    409 		break;
    410 
    411 	/*
    412 	 * Accept a connection.  Essentially all the work is
    413 	 * done at higher levels; just return the address
    414 	 * of the peer, storing through addr.
    415 	 */
    416 	case PRU_ACCEPT:
    417 		if (inp)
    418 			in_setpeeraddr(inp, nam);
    419 #ifdef INET6
    420 		else if (in6p)
    421 			in6_setpeeraddr(in6p, nam);
    422 #endif
    423 		break;
    424 
    425 	/*
    426 	 * Mark the connection as being incapable of further output.
    427 	 */
    428 	case PRU_SHUTDOWN:
    429 		socantsendmore(so);
    430 		tp = tcp_usrclosed(tp);
    431 		if (tp)
    432 			error = tcp_output(tp);
    433 		break;
    434 
    435 	/*
    436 	 * After a receive, possibly send window update to peer.
    437 	 */
    438 	case PRU_RCVD:
    439 		(void) tcp_output(tp);
    440 		break;
    441 
    442 	/*
    443 	 * Do a send by putting data in output queue and updating urgent
    444 	 * marker if URG set.  Possibly send more data.
    445 	 */
    446 	case PRU_SEND:
    447 		if (control && control->m_len) {
    448 			m_freem(control);
    449 			m_freem(m);
    450 			error = EINVAL;
    451 			break;
    452 		}
    453 		sbappend(&so->so_snd, m);
    454 		error = tcp_output(tp);
    455 		break;
    456 
    457 	/*
    458 	 * Abort the TCP.
    459 	 */
    460 	case PRU_ABORT:
    461 		tp = tcp_drop(tp, ECONNABORTED);
    462 		break;
    463 
    464 	case PRU_SENSE:
    465 		/*
    466 		 * stat: don't bother with a blocksize.
    467 		 */
    468 		splx(s);
    469 		return (0);
    470 
    471 	case PRU_RCVOOB:
    472 		if (control && control->m_len) {
    473 			m_freem(control);
    474 			m_freem(m);
    475 			error = EINVAL;
    476 			break;
    477 		}
    478 		if ((so->so_oobmark == 0 &&
    479 		    (so->so_state & SS_RCVATMARK) == 0) ||
    480 		    so->so_options & SO_OOBINLINE ||
    481 		    tp->t_oobflags & TCPOOB_HADDATA) {
    482 			error = EINVAL;
    483 			break;
    484 		}
    485 		if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
    486 			error = EWOULDBLOCK;
    487 			break;
    488 		}
    489 		m->m_len = 1;
    490 		*mtod(m, caddr_t) = tp->t_iobc;
    491 		if (((long)nam & MSG_PEEK) == 0)
    492 			tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
    493 		break;
    494 
    495 	case PRU_SENDOOB:
    496 		if (sbspace(&so->so_snd) < -512) {
    497 			m_freem(m);
    498 			error = ENOBUFS;
    499 			break;
    500 		}
    501 		/*
    502 		 * According to RFC961 (Assigned Protocols),
    503 		 * the urgent pointer points to the last octet
    504 		 * of urgent data.  We continue, however,
    505 		 * to consider it to indicate the first octet
    506 		 * of data past the urgent section.
    507 		 * Otherwise, snd_up should be one lower.
    508 		 */
    509 		sbappend(&so->so_snd, m);
    510 		tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
    511 		tp->t_force = 1;
    512 		error = tcp_output(tp);
    513 		tp->t_force = 0;
    514 		break;
    515 
    516 	case PRU_SOCKADDR:
    517 		if (inp)
    518 			in_setsockaddr(inp, nam);
    519 #ifdef INET6
    520 		else if (in6p)
    521 			in6_setsockaddr(in6p, nam);
    522 #endif
    523 		break;
    524 
    525 	case PRU_PEERADDR:
    526 		if (inp)
    527 			in_setpeeraddr(inp, nam);
    528 #ifdef INET6
    529 		else if (in6p)
    530 			in6_setpeeraddr(in6p, nam);
    531 #endif
    532 		break;
    533 
    534 	/*
    535 	 * TCP slow timer went off; going through this
    536 	 * routine for tracing's sake.
    537 	 */
    538 	case PRU_SLOWTIMO:
    539 		tp = tcp_timers(tp, (long)nam);
    540 		req |= (long)nam << 8;		/* for debug's sake */
    541 		break;
    542 
    543 	default:
    544 		panic("tcp_usrreq");
    545 	}
    546 	if (tp && (so->so_options & SO_DEBUG))
    547 		tcp_trace(TA_USER, ostate, tp, NULL, req);
    548 
    549 release:
    550 	splx(s);
    551 	return (error);
    552 }
    553 
    554 int
    555 tcp_ctloutput(op, so, level, optname, mp)
    556 	int op;
    557 	struct socket *so;
    558 	int level, optname;
    559 	struct mbuf **mp;
    560 {
    561 	int error = 0, s;
    562 	struct inpcb *inp;
    563 #ifdef INET6
    564 	register struct in6pcb *in6p;
    565 #endif
    566 	register struct tcpcb *tp;
    567 	register struct mbuf *m;
    568 	register int i;
    569 	int family;	/* family of the socket */
    570 
    571 	family = so->so_proto->pr_domain->dom_family;
    572 
    573 	s = splsoftnet();
    574 	switch (family) {
    575 	case PF_INET:
    576 		inp = sotoinpcb(so);
    577 #ifdef INET6
    578 		in6p = NULL;
    579 #endif
    580 		break;
    581 #ifdef INET6
    582 	case PF_INET6:
    583 		inp = NULL;
    584 		in6p = sotoin6pcb(so);
    585 		break;
    586 #endif
    587 	default:
    588 		splx(s);
    589 		return EAFNOSUPPORT;
    590 	}
    591 #ifndef INET6
    592 	if (inp == NULL)
    593 #else
    594 	if (inp == NULL && in6p == NULL)
    595 #endif
    596 	{
    597 		splx(s);
    598 		if (op == PRCO_SETOPT && *mp)
    599 			(void) m_free(*mp);
    600 		return (ECONNRESET);
    601 	}
    602 	if (level != IPPROTO_TCP) {
    603 		switch (family) {
    604 		case PF_INET:
    605 			error = ip_ctloutput(op, so, level, optname, mp);
    606 			break;
    607 #ifdef INET6
    608 		case PF_INET6:
    609 			error = ip6_ctloutput(op, so, level, optname, mp);
    610 			break;
    611 #endif
    612 		}
    613 		splx(s);
    614 		return (error);
    615 	}
    616 	if (inp)
    617 		tp = intotcpcb(inp);
    618 #ifdef INET6
    619 	else if (in6p)
    620 		tp = in6totcpcb(in6p);
    621 #endif
    622 	else
    623 		tp = NULL;
    624 
    625 	switch (op) {
    626 
    627 	case PRCO_SETOPT:
    628 		m = *mp;
    629 		switch (optname) {
    630 
    631 		case TCP_NODELAY:
    632 			if (m == NULL || m->m_len < sizeof (int))
    633 				error = EINVAL;
    634 			else if (*mtod(m, int *))
    635 				tp->t_flags |= TF_NODELAY;
    636 			else
    637 				tp->t_flags &= ~TF_NODELAY;
    638 			break;
    639 
    640 		case TCP_MAXSEG:
    641 			if (m && (i = *mtod(m, int *)) > 0 &&
    642 			    i <= tp->t_peermss)
    643 				tp->t_peermss = i;  /* limit on send size */
    644 			else
    645 				error = EINVAL;
    646 			break;
    647 
    648 		default:
    649 			error = ENOPROTOOPT;
    650 			break;
    651 		}
    652 		if (m)
    653 			(void) m_free(m);
    654 		break;
    655 
    656 	case PRCO_GETOPT:
    657 		*mp = m = m_get(M_WAIT, MT_SOOPTS);
    658 		m->m_len = sizeof(int);
    659 
    660 		switch (optname) {
    661 		case TCP_NODELAY:
    662 			*mtod(m, int *) = tp->t_flags & TF_NODELAY;
    663 			break;
    664 		case TCP_MAXSEG:
    665 			*mtod(m, int *) = tp->t_peermss;
    666 			break;
    667 		default:
    668 			error = ENOPROTOOPT;
    669 			break;
    670 		}
    671 		break;
    672 	}
    673 	splx(s);
    674 	return (error);
    675 }
    676 
    677 #ifndef TCP_SENDSPACE
    678 #define	TCP_SENDSPACE	1024*16;
    679 #endif
    680 int	tcp_sendspace = TCP_SENDSPACE;
    681 #ifndef TCP_RECVSPACE
    682 #define	TCP_RECVSPACE	1024*16;
    683 #endif
    684 int	tcp_recvspace = TCP_RECVSPACE;
    685 
    686 /*
    687  * Attach TCP protocol to socket, allocating
    688  * internet protocol control block, tcp control block,
    689  * bufer space, and entering LISTEN state if to accept connections.
    690  */
    691 int
    692 tcp_attach(so)
    693 	struct socket *so;
    694 {
    695 	register struct tcpcb *tp;
    696 	struct inpcb *inp;
    697 #ifdef INET6
    698 	struct in6pcb *in6p;
    699 #endif
    700 	int error;
    701 	int family;	/* family of the socket */
    702 
    703 	family = so->so_proto->pr_domain->dom_family;
    704 
    705 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
    706 		error = soreserve(so, tcp_sendspace, tcp_recvspace);
    707 		if (error)
    708 			return (error);
    709 	}
    710 	switch (family) {
    711 	case PF_INET:
    712 		error = in_pcballoc(so, &tcbtable);
    713 		if (error)
    714 			return (error);
    715 		inp = sotoinpcb(so);
    716 #ifdef INET6
    717 		in6p = NULL;
    718 #endif
    719 		break;
    720 #ifdef INET6
    721 	case PF_INET6:
    722 		error = in6_pcballoc(so, &tcb6);
    723 		if (error)
    724 			return (error);
    725 		inp = NULL;
    726 		in6p = sotoin6pcb(so);
    727 		break;
    728 #endif
    729 	default:
    730 		return EAFNOSUPPORT;
    731 	}
    732 #ifdef IPSEC
    733 	if (inp) {
    734 		error = ipsec_init_policy(&inp->inp_sp);
    735 		if (error != 0) {
    736 			in_pcbdetach(inp);
    737 			return (error);
    738 		}
    739 	}
    740 #ifdef INET6
    741 	else if (in6p) {
    742 		error = ipsec_init_policy(&in6p->in6p_sp);
    743 		if (error != 0) {
    744 			in6_pcbdetach(in6p);
    745 			return (error);
    746 		}
    747 	}
    748 #endif
    749 #endif /*IPSEC*/
    750 	if (inp)
    751 		tp = tcp_newtcpcb(family, (void *)inp);
    752 #ifdef INET6
    753 	else if (in6p)
    754 		tp = tcp_newtcpcb(family, (void *)in6p);
    755 #endif
    756 	else
    757 		tp = NULL;
    758 
    759 	if (tp == 0) {
    760 		int nofd = so->so_state & SS_NOFDREF;	/* XXX */
    761 
    762 		so->so_state &= ~SS_NOFDREF;	/* don't free the socket yet */
    763 		if (inp)
    764 			in_pcbdetach(inp);
    765 #ifdef INET6
    766 		else if (in6p)
    767 			in6_pcbdetach(in6p);
    768 #endif
    769 		so->so_state |= nofd;
    770 		return (ENOBUFS);
    771 	}
    772 	tp->t_state = TCPS_CLOSED;
    773 	return (0);
    774 }
    775 
    776 /*
    777  * Initiate (or continue) disconnect.
    778  * If embryonic state, just send reset (once).
    779  * If in ``let data drain'' option and linger null, just drop.
    780  * Otherwise (hard), mark socket disconnecting and drop
    781  * current input data; switch states based on user close, and
    782  * send segment to peer (with FIN).
    783  */
    784 struct tcpcb *
    785 tcp_disconnect(tp)
    786 	register struct tcpcb *tp;
    787 {
    788 	struct socket *so;
    789 
    790 	if (tp->t_inpcb)
    791 		so = tp->t_inpcb->inp_socket;
    792 #ifdef INET6
    793 	else if (tp->t_in6pcb)
    794 		so = tp->t_in6pcb->in6p_socket;
    795 #endif
    796 	else
    797 		so = NULL;
    798 
    799 	if (TCPS_HAVEESTABLISHED(tp->t_state) == 0)
    800 		tp = tcp_close(tp);
    801 	else if ((so->so_options & SO_LINGER) && so->so_linger == 0)
    802 		tp = tcp_drop(tp, 0);
    803 	else {
    804 		soisdisconnecting(so);
    805 		sbflush(&so->so_rcv);
    806 		tp = tcp_usrclosed(tp);
    807 		if (tp)
    808 			(void) tcp_output(tp);
    809 	}
    810 	return (tp);
    811 }
    812 
    813 /*
    814  * User issued close, and wish to trail through shutdown states:
    815  * if never received SYN, just forget it.  If got a SYN from peer,
    816  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
    817  * If already got a FIN from peer, then almost done; go to LAST_ACK
    818  * state.  In all other cases, have already sent FIN to peer (e.g.
    819  * after PRU_SHUTDOWN), and just have to play tedious game waiting
    820  * for peer to send FIN or not respond to keep-alives, etc.
    821  * We can let the user exit from the close as soon as the FIN is acked.
    822  */
    823 struct tcpcb *
    824 tcp_usrclosed(tp)
    825 	register struct tcpcb *tp;
    826 {
    827 
    828 	switch (tp->t_state) {
    829 
    830 	case TCPS_CLOSED:
    831 	case TCPS_LISTEN:
    832 	case TCPS_SYN_SENT:
    833 		tp->t_state = TCPS_CLOSED;
    834 		tp = tcp_close(tp);
    835 		break;
    836 
    837 	case TCPS_SYN_RECEIVED:
    838 	case TCPS_ESTABLISHED:
    839 		tp->t_state = TCPS_FIN_WAIT_1;
    840 		break;
    841 
    842 	case TCPS_CLOSE_WAIT:
    843 		tp->t_state = TCPS_LAST_ACK;
    844 		break;
    845 	}
    846 	if (tp && tp->t_state >= TCPS_FIN_WAIT_2) {
    847 		struct socket *so;
    848 		if (tp->t_inpcb)
    849 			so = tp->t_inpcb->inp_socket;
    850 #ifdef INET6
    851 		else if (tp->t_in6pcb)
    852 			so = tp->t_in6pcb->in6p_socket;
    853 #endif
    854 		else
    855 			so = NULL;
    856 		soisdisconnected(so);
    857 		/*
    858 		 * If we are in FIN_WAIT_2, we arrived here because the
    859 		 * application did a shutdown of the send side.  Like the
    860 		 * case of a transition from FIN_WAIT_1 to FIN_WAIT_2 after
    861 		 * a full close, we start a timer to make sure sockets are
    862 		 * not left in FIN_WAIT_2 forever.
    863 		 */
    864 		if ((tp->t_state == TCPS_FIN_WAIT_2) && (tcp_maxidle > 0))
    865 			TCP_TIMER_ARM(tp, TCPT_2MSL, tcp_maxidle);
    866 	}
    867 	return (tp);
    868 }
    869 
    870 static struct {
    871 	 unsigned int valid : 1;
    872 	 unsigned int rdonly : 1;
    873 	 int *var;
    874 	 int val;
    875 	 } tcp_ctlvars[] = TCPCTL_VARIABLES;
    876 
    877 /*
    878  * Sysctl for tcp variables.
    879  */
    880 int
    881 tcp_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
    882 	int *name;
    883 	u_int namelen;
    884 	void *oldp;
    885 	size_t *oldlenp;
    886 	void *newp;
    887 	size_t newlen;
    888 {
    889 	/* All sysctl names at this level are terminal. */
    890 	if (namelen != 1)
    891 		return (ENOTDIR);
    892 
    893 	if (name[0] < sizeof(tcp_ctlvars)/sizeof(tcp_ctlvars[0])
    894 	    && tcp_ctlvars[name[0]].valid) {
    895 		if (tcp_ctlvars[name[0]].rdonly)
    896 			return (sysctl_rdint(oldp, oldlenp, newp,
    897 			    tcp_ctlvars[name[0]].val));
    898 		else
    899 			return (sysctl_int(oldp, oldlenp, newp, newlen,
    900 			    tcp_ctlvars[name[0]].var));
    901 	}
    902 
    903 	return (ENOPROTOOPT);
    904 }
    905