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tcp_usrreq.c revision 1.78
      1 /*	$NetBSD: tcp_usrreq.c,v 1.78 2003/06/26 17:32:22 christos 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 <sys/cdefs.h>
    105 __KERNEL_RCSID(0, "$NetBSD: tcp_usrreq.c,v 1.78 2003/06/26 17:32:22 christos Exp $");
    106 
    107 #include "opt_inet.h"
    108 #include "opt_ipsec.h"
    109 #include "opt_tcp_debug.h"
    110 #include "opt_mbuftrace.h"
    111 
    112 #include <sys/param.h>
    113 #include <sys/systm.h>
    114 #include <sys/kernel.h>
    115 #include <sys/malloc.h>
    116 #include <sys/mbuf.h>
    117 #include <sys/socket.h>
    118 #include <sys/socketvar.h>
    119 #include <sys/protosw.h>
    120 #include <sys/errno.h>
    121 #include <sys/stat.h>
    122 #include <sys/proc.h>
    123 #include <sys/domain.h>
    124 #include <sys/sysctl.h>
    125 
    126 #include <net/if.h>
    127 #include <net/route.h>
    128 
    129 #include <netinet/in.h>
    130 #include <netinet/in_systm.h>
    131 #include <netinet/in_var.h>
    132 #include <netinet/ip.h>
    133 #include <netinet/in_pcb.h>
    134 #include <netinet/ip_var.h>
    135 
    136 #ifdef INET6
    137 #ifndef INET
    138 #include <netinet/in.h>
    139 #endif
    140 #include <netinet/ip6.h>
    141 #include <netinet6/in6_pcb.h>
    142 #include <netinet6/ip6_var.h>
    143 #endif
    144 
    145 #include <netinet/tcp.h>
    146 #include <netinet/tcp_fsm.h>
    147 #include <netinet/tcp_seq.h>
    148 #include <netinet/tcp_timer.h>
    149 #include <netinet/tcp_var.h>
    150 #include <netinet/tcpip.h>
    151 #include <netinet/tcp_debug.h>
    152 
    153 #include "opt_tcp_space.h"
    154 
    155 #ifdef IPSEC
    156 #include <netinet6/ipsec.h>
    157 #endif /*IPSEC*/
    158 
    159 /*
    160  * TCP protocol interface to socket abstraction.
    161  */
    162 extern	char *tcpstates[];
    163 
    164 static int tcp_sysctl_ident(int *, u_int, void *, size_t *, void *, size_t);
    165 
    166 /*
    167  * Process a TCP user request for TCP tb.  If this is a send request
    168  * then m is the mbuf chain of send data.  If this is a timer expiration
    169  * (called from the software clock routine), then timertype tells which timer.
    170  */
    171 /*ARGSUSED*/
    172 int
    173 tcp_usrreq(so, req, m, nam, control, p)
    174 	struct socket *so;
    175 	int req;
    176 	struct mbuf *m, *nam, *control;
    177 	struct proc *p;
    178 {
    179 	struct inpcb *inp;
    180 #ifdef INET6
    181 	struct in6pcb *in6p;
    182 #endif
    183 	struct tcpcb *tp = NULL;
    184 	int s;
    185 	int error = 0;
    186 #ifdef TCP_DEBUG
    187 	int ostate = 0;
    188 #endif
    189 	int family;	/* family of the socket */
    190 
    191 	family = so->so_proto->pr_domain->dom_family;
    192 
    193 	if (req == PRU_CONTROL) {
    194 		switch (family) {
    195 #ifdef INET
    196 		case PF_INET:
    197 			return (in_control(so, (long)m, (caddr_t)nam,
    198 			    (struct ifnet *)control, p));
    199 #endif
    200 #ifdef INET6
    201 		case PF_INET6:
    202 			return (in6_control(so, (long)m, (caddr_t)nam,
    203 			    (struct ifnet *)control, p));
    204 #endif
    205 		default:
    206 			return EAFNOSUPPORT;
    207 		}
    208 	}
    209 
    210 	if (req == PRU_PURGEIF) {
    211 		switch (family) {
    212 #ifdef INET
    213 		case PF_INET:
    214 			in_pcbpurgeif0(&tcbtable, (struct ifnet *)control);
    215 			in_purgeif((struct ifnet *)control);
    216 			in_pcbpurgeif(&tcbtable, (struct ifnet *)control);
    217 			break;
    218 #endif
    219 #ifdef INET6
    220 		case PF_INET6:
    221 			in6_pcbpurgeif0(&tcb6, (struct ifnet *)control);
    222 			in6_purgeif((struct ifnet *)control);
    223 			in6_pcbpurgeif(&tcb6, (struct ifnet *)control);
    224 			break;
    225 #endif
    226 		default:
    227 			return (EAFNOSUPPORT);
    228 		}
    229 		return (0);
    230 	}
    231 
    232 	s = splsoftnet();
    233 	switch (family) {
    234 #ifdef INET
    235 	case PF_INET:
    236 		inp = sotoinpcb(so);
    237 #ifdef INET6
    238 		in6p = NULL;
    239 #endif
    240 		break;
    241 #endif
    242 #ifdef INET6
    243 	case PF_INET6:
    244 		inp = NULL;
    245 		in6p = sotoin6pcb(so);
    246 		break;
    247 #endif
    248 	default:
    249 		splx(s);
    250 		return EAFNOSUPPORT;
    251 	}
    252 
    253 #ifdef DIAGNOSTIC
    254 #ifdef INET6
    255 	if (inp && in6p)
    256 		panic("tcp_usrreq: both inp and in6p set to non-NULL");
    257 #endif
    258 	if (req != PRU_SEND && req != PRU_SENDOOB && control)
    259 		panic("tcp_usrreq: unexpected control mbuf");
    260 #endif
    261 	/*
    262 	 * When a TCP is attached to a socket, then there will be
    263 	 * a (struct inpcb) pointed at by the socket, and this
    264 	 * structure will point at a subsidary (struct tcpcb).
    265 	 */
    266 #ifndef INET6
    267 	if (inp == 0 && req != PRU_ATTACH)
    268 #else
    269 	if ((inp == 0 && in6p == 0) && req != PRU_ATTACH)
    270 #endif
    271 	{
    272 		error = EINVAL;
    273 		goto release;
    274 	}
    275 #ifdef INET
    276 	if (inp) {
    277 		tp = intotcpcb(inp);
    278 		/* WHAT IF TP IS 0? */
    279 #ifdef KPROF
    280 		tcp_acounts[tp->t_state][req]++;
    281 #endif
    282 #ifdef TCP_DEBUG
    283 		ostate = tp->t_state;
    284 #endif
    285 	}
    286 #endif
    287 #ifdef INET6
    288 	if (in6p) {
    289 		tp = in6totcpcb(in6p);
    290 		/* WHAT IF TP IS 0? */
    291 #ifdef KPROF
    292 		tcp_acounts[tp->t_state][req]++;
    293 #endif
    294 #ifdef TCP_DEBUG
    295 		ostate = tp->t_state;
    296 #endif
    297 	}
    298 #endif
    299 
    300 	switch (req) {
    301 
    302 	/*
    303 	 * TCP attaches to socket via PRU_ATTACH, reserving space,
    304 	 * and an internet control block.
    305 	 */
    306 	case PRU_ATTACH:
    307 #ifndef INET6
    308 		if (inp != 0)
    309 #else
    310 		if (inp != 0 || in6p != 0)
    311 #endif
    312 		{
    313 			error = EISCONN;
    314 			break;
    315 		}
    316 		error = tcp_attach(so);
    317 		if (error)
    318 			break;
    319 		if ((so->so_options & SO_LINGER) && so->so_linger == 0)
    320 			so->so_linger = TCP_LINGERTIME;
    321 		tp = sototcpcb(so);
    322 		break;
    323 
    324 	/*
    325 	 * PRU_DETACH detaches the TCP protocol from the socket.
    326 	 */
    327 	case PRU_DETACH:
    328 		tp = tcp_disconnect(tp);
    329 		break;
    330 
    331 	/*
    332 	 * Give the socket an address.
    333 	 */
    334 	case PRU_BIND:
    335 		switch (family) {
    336 #ifdef INET
    337 		case PF_INET:
    338 			error = in_pcbbind(inp, nam, p);
    339 			break;
    340 #endif
    341 #ifdef INET6
    342 		case PF_INET6:
    343 			error = in6_pcbbind(in6p, nam, p);
    344 			if (!error) {
    345 				/* mapped addr case */
    346 				if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_laddr))
    347 					tp->t_family = AF_INET;
    348 				else
    349 					tp->t_family = AF_INET6;
    350 			}
    351 			break;
    352 #endif
    353 		}
    354 		break;
    355 
    356 	/*
    357 	 * Prepare to accept connections.
    358 	 */
    359 	case PRU_LISTEN:
    360 #ifdef INET
    361 		if (inp && inp->inp_lport == 0) {
    362 			error = in_pcbbind(inp, (struct mbuf *)0,
    363 			    (struct proc *)0);
    364 			if (error)
    365 				break;
    366 		}
    367 #endif
    368 #ifdef INET6
    369 		if (in6p && in6p->in6p_lport == 0) {
    370 			error = in6_pcbbind(in6p, (struct mbuf *)0,
    371 			    (struct proc *)0);
    372 			if (error)
    373 				break;
    374 		}
    375 #endif
    376 		tp->t_state = TCPS_LISTEN;
    377 		break;
    378 
    379 	/*
    380 	 * Initiate connection to peer.
    381 	 * Create a template for use in transmissions on this connection.
    382 	 * Enter SYN_SENT state, and mark socket as connecting.
    383 	 * Start keep-alive timer, and seed output sequence space.
    384 	 * Send initial segment on connection.
    385 	 */
    386 	case PRU_CONNECT:
    387 #ifdef INET
    388 		if (inp) {
    389 			if (inp->inp_lport == 0) {
    390 				error = in_pcbbind(inp, (struct mbuf *)0,
    391 				    (struct proc *)0);
    392 				if (error)
    393 					break;
    394 			}
    395 			error = in_pcbconnect(inp, nam);
    396 		}
    397 #endif
    398 #ifdef INET6
    399 		if (in6p) {
    400 			if (in6p->in6p_lport == 0) {
    401 				error = in6_pcbbind(in6p, (struct mbuf *)0,
    402 				    (struct proc *)0);
    403 				if (error)
    404 					break;
    405 			}
    406 			error = in6_pcbconnect(in6p, nam);
    407 			if (!error) {
    408 				/* mapped addr case */
    409 				if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr))
    410 					tp->t_family = AF_INET;
    411 				else
    412 					tp->t_family = AF_INET6;
    413 			}
    414 		}
    415 #endif
    416 		if (error)
    417 			break;
    418 		tp->t_template = tcp_template(tp);
    419 		if (tp->t_template == 0) {
    420 #ifdef INET
    421 			if (inp)
    422 				in_pcbdisconnect(inp);
    423 #endif
    424 #ifdef INET6
    425 			if (in6p)
    426 				in6_pcbdisconnect(in6p);
    427 #endif
    428 			error = ENOBUFS;
    429 			break;
    430 		}
    431 		/* Compute window scaling to request.  */
    432 		while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
    433 		    (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
    434 			tp->request_r_scale++;
    435 		soisconnecting(so);
    436 		tcpstat.tcps_connattempt++;
    437 		tp->t_state = TCPS_SYN_SENT;
    438 		TCP_TIMER_ARM(tp, TCPT_KEEP, TCPTV_KEEP_INIT);
    439 		tp->iss = tcp_new_iss(tp, 0);
    440 		tcp_sendseqinit(tp);
    441 		error = tcp_output(tp);
    442 		break;
    443 
    444 	/*
    445 	 * Create a TCP connection between two sockets.
    446 	 */
    447 	case PRU_CONNECT2:
    448 		error = EOPNOTSUPP;
    449 		break;
    450 
    451 	/*
    452 	 * Initiate disconnect from peer.
    453 	 * If connection never passed embryonic stage, just drop;
    454 	 * else if don't need to let data drain, then can just drop anyways,
    455 	 * else have to begin TCP shutdown process: mark socket disconnecting,
    456 	 * drain unread data, state switch to reflect user close, and
    457 	 * send segment (e.g. FIN) to peer.  Socket will be really disconnected
    458 	 * when peer sends FIN and acks ours.
    459 	 *
    460 	 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
    461 	 */
    462 	case PRU_DISCONNECT:
    463 		tp = tcp_disconnect(tp);
    464 		break;
    465 
    466 	/*
    467 	 * Accept a connection.  Essentially all the work is
    468 	 * done at higher levels; just return the address
    469 	 * of the peer, storing through addr.
    470 	 */
    471 	case PRU_ACCEPT:
    472 #ifdef INET
    473 		if (inp)
    474 			in_setpeeraddr(inp, nam);
    475 #endif
    476 #ifdef INET6
    477 		if (in6p)
    478 			in6_setpeeraddr(in6p, nam);
    479 #endif
    480 		break;
    481 
    482 	/*
    483 	 * Mark the connection as being incapable of further output.
    484 	 */
    485 	case PRU_SHUTDOWN:
    486 		socantsendmore(so);
    487 		tp = tcp_usrclosed(tp);
    488 		if (tp)
    489 			error = tcp_output(tp);
    490 		break;
    491 
    492 	/*
    493 	 * After a receive, possibly send window update to peer.
    494 	 */
    495 	case PRU_RCVD:
    496 		/*
    497 		 * soreceive() calls this function when a user receives
    498 		 * ancillary data on a listening socket. We don't call
    499 		 * tcp_output in such a case, since there is no header
    500 		 * template for a listening socket and hence the kernel
    501 		 * will panic.
    502 		 */
    503 		if ((so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) != 0)
    504 			(void) tcp_output(tp);
    505 		break;
    506 
    507 	/*
    508 	 * Do a send by putting data in output queue and updating urgent
    509 	 * marker if URG set.  Possibly send more data.
    510 	 */
    511 	case PRU_SEND:
    512 		if (control && control->m_len) {
    513 			m_freem(control);
    514 			m_freem(m);
    515 			error = EINVAL;
    516 			break;
    517 		}
    518 		sbappendstream(&so->so_snd, m);
    519 		error = tcp_output(tp);
    520 		break;
    521 
    522 	/*
    523 	 * Abort the TCP.
    524 	 */
    525 	case PRU_ABORT:
    526 		tp = tcp_drop(tp, ECONNABORTED);
    527 		break;
    528 
    529 	case PRU_SENSE:
    530 		/*
    531 		 * stat: don't bother with a blocksize.
    532 		 */
    533 		splx(s);
    534 		return (0);
    535 
    536 	case PRU_RCVOOB:
    537 		if (control && control->m_len) {
    538 			m_freem(control);
    539 			m_freem(m);
    540 			error = EINVAL;
    541 			break;
    542 		}
    543 		if ((so->so_oobmark == 0 &&
    544 		    (so->so_state & SS_RCVATMARK) == 0) ||
    545 		    so->so_options & SO_OOBINLINE ||
    546 		    tp->t_oobflags & TCPOOB_HADDATA) {
    547 			error = EINVAL;
    548 			break;
    549 		}
    550 		if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
    551 			error = EWOULDBLOCK;
    552 			break;
    553 		}
    554 		m->m_len = 1;
    555 		*mtod(m, caddr_t) = tp->t_iobc;
    556 		if (((long)nam & MSG_PEEK) == 0)
    557 			tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
    558 		break;
    559 
    560 	case PRU_SENDOOB:
    561 		if (sbspace(&so->so_snd) < -512) {
    562 			m_freem(m);
    563 			error = ENOBUFS;
    564 			break;
    565 		}
    566 		/*
    567 		 * According to RFC961 (Assigned Protocols),
    568 		 * the urgent pointer points to the last octet
    569 		 * of urgent data.  We continue, however,
    570 		 * to consider it to indicate the first octet
    571 		 * of data past the urgent section.
    572 		 * Otherwise, snd_up should be one lower.
    573 		 */
    574 		sbappendstream(&so->so_snd, m);
    575 		tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
    576 		tp->t_force = 1;
    577 		error = tcp_output(tp);
    578 		tp->t_force = 0;
    579 		break;
    580 
    581 	case PRU_SOCKADDR:
    582 #ifdef INET
    583 		if (inp)
    584 			in_setsockaddr(inp, nam);
    585 #endif
    586 #ifdef INET6
    587 		if (in6p)
    588 			in6_setsockaddr(in6p, nam);
    589 #endif
    590 		break;
    591 
    592 	case PRU_PEERADDR:
    593 #ifdef INET
    594 		if (inp)
    595 			in_setpeeraddr(inp, nam);
    596 #endif
    597 #ifdef INET6
    598 		if (in6p)
    599 			in6_setpeeraddr(in6p, nam);
    600 #endif
    601 		break;
    602 
    603 	default:
    604 		panic("tcp_usrreq");
    605 	}
    606 #ifdef TCP_DEBUG
    607 	if (tp && (so->so_options & SO_DEBUG))
    608 		tcp_trace(TA_USER, ostate, tp, NULL, req);
    609 #endif
    610 
    611 release:
    612 	splx(s);
    613 	return (error);
    614 }
    615 
    616 int
    617 tcp_ctloutput(op, so, level, optname, mp)
    618 	int op;
    619 	struct socket *so;
    620 	int level, optname;
    621 	struct mbuf **mp;
    622 {
    623 	int error = 0, s;
    624 	struct inpcb *inp;
    625 #ifdef INET6
    626 	struct in6pcb *in6p;
    627 #endif
    628 	struct tcpcb *tp;
    629 	struct mbuf *m;
    630 	int i;
    631 	int family;	/* family of the socket */
    632 
    633 	family = so->so_proto->pr_domain->dom_family;
    634 
    635 	s = splsoftnet();
    636 	switch (family) {
    637 #ifdef INET
    638 	case PF_INET:
    639 		inp = sotoinpcb(so);
    640 #ifdef INET6
    641 		in6p = NULL;
    642 #endif
    643 		break;
    644 #endif
    645 #ifdef INET6
    646 	case PF_INET6:
    647 		inp = NULL;
    648 		in6p = sotoin6pcb(so);
    649 		break;
    650 #endif
    651 	default:
    652 		splx(s);
    653 		return EAFNOSUPPORT;
    654 	}
    655 #ifndef INET6
    656 	if (inp == NULL)
    657 #else
    658 	if (inp == NULL && in6p == NULL)
    659 #endif
    660 	{
    661 		splx(s);
    662 		if (op == PRCO_SETOPT && *mp)
    663 			(void) m_free(*mp);
    664 		return (ECONNRESET);
    665 	}
    666 	if (level != IPPROTO_TCP) {
    667 		switch (family) {
    668 #ifdef INET
    669 		case PF_INET:
    670 			error = ip_ctloutput(op, so, level, optname, mp);
    671 			break;
    672 #endif
    673 #ifdef INET6
    674 		case PF_INET6:
    675 			error = ip6_ctloutput(op, so, level, optname, mp);
    676 			break;
    677 #endif
    678 		}
    679 		splx(s);
    680 		return (error);
    681 	}
    682 	if (inp)
    683 		tp = intotcpcb(inp);
    684 #ifdef INET6
    685 	else if (in6p)
    686 		tp = in6totcpcb(in6p);
    687 #endif
    688 	else
    689 		tp = NULL;
    690 
    691 	switch (op) {
    692 
    693 	case PRCO_SETOPT:
    694 		m = *mp;
    695 		switch (optname) {
    696 
    697 		case TCP_NODELAY:
    698 			if (m == NULL || m->m_len < sizeof (int))
    699 				error = EINVAL;
    700 			else if (*mtod(m, int *))
    701 				tp->t_flags |= TF_NODELAY;
    702 			else
    703 				tp->t_flags &= ~TF_NODELAY;
    704 			break;
    705 
    706 		case TCP_MAXSEG:
    707 			if (m && (i = *mtod(m, int *)) > 0 &&
    708 			    i <= tp->t_peermss)
    709 				tp->t_peermss = i;  /* limit on send size */
    710 			else
    711 				error = EINVAL;
    712 			break;
    713 
    714 		default:
    715 			error = ENOPROTOOPT;
    716 			break;
    717 		}
    718 		if (m)
    719 			(void) m_free(m);
    720 		break;
    721 
    722 	case PRCO_GETOPT:
    723 		*mp = m = m_get(M_WAIT, MT_SOOPTS);
    724 		m->m_len = sizeof(int);
    725 		MCLAIM(m, so->so_mowner);
    726 
    727 		switch (optname) {
    728 		case TCP_NODELAY:
    729 			*mtod(m, int *) = tp->t_flags & TF_NODELAY;
    730 			break;
    731 		case TCP_MAXSEG:
    732 			*mtod(m, int *) = tp->t_peermss;
    733 			break;
    734 		default:
    735 			error = ENOPROTOOPT;
    736 			break;
    737 		}
    738 		break;
    739 	}
    740 	splx(s);
    741 	return (error);
    742 }
    743 
    744 #ifndef TCP_SENDSPACE
    745 #define	TCP_SENDSPACE	1024*16
    746 #endif
    747 int	tcp_sendspace = TCP_SENDSPACE;
    748 #ifndef TCP_RECVSPACE
    749 #define	TCP_RECVSPACE	1024*16
    750 #endif
    751 int	tcp_recvspace = TCP_RECVSPACE;
    752 
    753 /*
    754  * Attach TCP protocol to socket, allocating
    755  * internet protocol control block, tcp control block,
    756  * bufer space, and entering LISTEN state if to accept connections.
    757  */
    758 int
    759 tcp_attach(so)
    760 	struct socket *so;
    761 {
    762 	struct tcpcb *tp;
    763 	struct inpcb *inp;
    764 #ifdef INET6
    765 	struct in6pcb *in6p;
    766 #endif
    767 	int error;
    768 	int family;	/* family of the socket */
    769 
    770 	family = so->so_proto->pr_domain->dom_family;
    771 
    772 #ifdef MBUFTRACE
    773 	so->so_mowner = &tcp_mowner;
    774 	so->so_rcv.sb_mowner = &tcp_rx_mowner;
    775 	so->so_snd.sb_mowner = &tcp_tx_mowner;
    776 #endif
    777 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
    778 		error = soreserve(so, tcp_sendspace, tcp_recvspace);
    779 		if (error)
    780 			return (error);
    781 	}
    782 	switch (family) {
    783 #ifdef INET
    784 	case PF_INET:
    785 		error = in_pcballoc(so, &tcbtable);
    786 		if (error)
    787 			return (error);
    788 		inp = sotoinpcb(so);
    789 #ifdef INET6
    790 		in6p = NULL;
    791 #endif
    792 		break;
    793 #endif
    794 #ifdef INET6
    795 	case PF_INET6:
    796 		error = in6_pcballoc(so, &tcb6);
    797 		if (error)
    798 			return (error);
    799 		inp = NULL;
    800 		in6p = sotoin6pcb(so);
    801 		break;
    802 #endif
    803 	default:
    804 		return EAFNOSUPPORT;
    805 	}
    806 	if (inp)
    807 		tp = tcp_newtcpcb(family, (void *)inp);
    808 #ifdef INET6
    809 	else if (in6p)
    810 		tp = tcp_newtcpcb(family, (void *)in6p);
    811 #endif
    812 	else
    813 		tp = NULL;
    814 
    815 	if (tp == 0) {
    816 		int nofd = so->so_state & SS_NOFDREF;	/* XXX */
    817 
    818 		so->so_state &= ~SS_NOFDREF;	/* don't free the socket yet */
    819 #ifdef INET
    820 		if (inp)
    821 			in_pcbdetach(inp);
    822 #endif
    823 #ifdef INET6
    824 		if (in6p)
    825 			in6_pcbdetach(in6p);
    826 #endif
    827 		so->so_state |= nofd;
    828 		return (ENOBUFS);
    829 	}
    830 	tp->t_state = TCPS_CLOSED;
    831 	return (0);
    832 }
    833 
    834 /*
    835  * Initiate (or continue) disconnect.
    836  * If embryonic state, just send reset (once).
    837  * If in ``let data drain'' option and linger null, just drop.
    838  * Otherwise (hard), mark socket disconnecting and drop
    839  * current input data; switch states based on user close, and
    840  * send segment to peer (with FIN).
    841  */
    842 struct tcpcb *
    843 tcp_disconnect(tp)
    844 	struct tcpcb *tp;
    845 {
    846 	struct socket *so;
    847 
    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 
    857 	if (TCPS_HAVEESTABLISHED(tp->t_state) == 0)
    858 		tp = tcp_close(tp);
    859 	else if ((so->so_options & SO_LINGER) && so->so_linger == 0)
    860 		tp = tcp_drop(tp, 0);
    861 	else {
    862 		soisdisconnecting(so);
    863 		sbflush(&so->so_rcv);
    864 		tp = tcp_usrclosed(tp);
    865 		if (tp)
    866 			(void) tcp_output(tp);
    867 	}
    868 	return (tp);
    869 }
    870 
    871 /*
    872  * User issued close, and wish to trail through shutdown states:
    873  * if never received SYN, just forget it.  If got a SYN from peer,
    874  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
    875  * If already got a FIN from peer, then almost done; go to LAST_ACK
    876  * state.  In all other cases, have already sent FIN to peer (e.g.
    877  * after PRU_SHUTDOWN), and just have to play tedious game waiting
    878  * for peer to send FIN or not respond to keep-alives, etc.
    879  * We can let the user exit from the close as soon as the FIN is acked.
    880  */
    881 struct tcpcb *
    882 tcp_usrclosed(tp)
    883 	struct tcpcb *tp;
    884 {
    885 
    886 	switch (tp->t_state) {
    887 
    888 	case TCPS_CLOSED:
    889 	case TCPS_LISTEN:
    890 	case TCPS_SYN_SENT:
    891 		tp->t_state = TCPS_CLOSED;
    892 		tp = tcp_close(tp);
    893 		break;
    894 
    895 	case TCPS_SYN_RECEIVED:
    896 	case TCPS_ESTABLISHED:
    897 		tp->t_state = TCPS_FIN_WAIT_1;
    898 		break;
    899 
    900 	case TCPS_CLOSE_WAIT:
    901 		tp->t_state = TCPS_LAST_ACK;
    902 		break;
    903 	}
    904 	if (tp && tp->t_state >= TCPS_FIN_WAIT_2) {
    905 		struct socket *so;
    906 		if (tp->t_inpcb)
    907 			so = tp->t_inpcb->inp_socket;
    908 #ifdef INET6
    909 		else if (tp->t_in6pcb)
    910 			so = tp->t_in6pcb->in6p_socket;
    911 #endif
    912 		else
    913 			so = NULL;
    914 		soisdisconnected(so);
    915 		/*
    916 		 * If we are in FIN_WAIT_2, we arrived here because the
    917 		 * application did a shutdown of the send side.  Like the
    918 		 * case of a transition from FIN_WAIT_1 to FIN_WAIT_2 after
    919 		 * a full close, we start a timer to make sure sockets are
    920 		 * not left in FIN_WAIT_2 forever.
    921 		 */
    922 		if ((tp->t_state == TCPS_FIN_WAIT_2) && (tcp_maxidle > 0))
    923 			TCP_TIMER_ARM(tp, TCPT_2MSL, tcp_maxidle);
    924 	}
    925 	return (tp);
    926 }
    927 
    928 static const struct {
    929 	 unsigned int valid : 1;
    930 	 unsigned int rdonly : 1;
    931 	 int *var;
    932 	 int val;
    933 	 } tcp_ctlvars[] = TCPCTL_VARIABLES;
    934 
    935 /*
    936  * Sysctl for tcp variables.
    937  */
    938 int
    939 tcp_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
    940 	int *name;
    941 	u_int namelen;
    942 	void *oldp;
    943 	size_t *oldlenp;
    944 	void *newp;
    945 	size_t newlen;
    946 {
    947 	int error, saved_value = 0;
    948 
    949 	if (name[0] == TCPCTL_IDENT)
    950 		return tcp_sysctl_ident(&name[1], namelen - 1, oldp, oldlenp,
    951 		    newp, newlen);
    952 
    953 	/* All sysctl names at this level are terminal. */
    954 	if (namelen != 1)
    955 		return (ENOTDIR);
    956 
    957 	if (name[0] < sizeof(tcp_ctlvars)/sizeof(tcp_ctlvars[0])
    958 	    && tcp_ctlvars[name[0]].valid) {
    959 		if (tcp_ctlvars[name[0]].rdonly) {
    960 			return (sysctl_rdint(oldp, oldlenp, newp,
    961 			    tcp_ctlvars[name[0]].val));
    962 		} else {
    963 			switch (name[0]) {
    964 			case TCPCTL_MSSDFLT:
    965 				saved_value = tcp_mssdflt;
    966 				break;
    967 			}
    968 			error = sysctl_int(oldp, oldlenp, newp, newlen,
    969 			    tcp_ctlvars[name[0]].var);
    970 			if (error)
    971 				return (error);
    972 			switch (name[0]) {
    973 			case TCPCTL_MSSDFLT:
    974 				if (tcp_mssdflt < 32) {
    975 					tcp_mssdflt = saved_value;
    976 					return (EINVAL);
    977 				}
    978 				break;
    979 			}
    980 			return (0);
    981 		}
    982 	}
    983 
    984 	return (ENOPROTOOPT);
    985 }
    986 
    987 
    988 static int
    989 tcp_sysctl_ident(int *name, u_int namelen, void *oldp, size_t *oldlenp,
    990     void *newp, size_t newlen)
    991 {
    992 	struct inpcb *inb;
    993 	struct in_addr laddr, raddr;
    994 	u_int lport, rport;
    995 	uid_t uid;
    996 	int error;
    997 
    998 	if (*oldlenp != sizeof(uid_t))
    999 		return ENOMEM;
   1000 	if (!oldp || *oldlenp != sizeof(uid_t))
   1001 		return ENOMEM;
   1002 	if (namelen != 4)
   1003 		return EINVAL;
   1004 
   1005 	raddr.s_addr = (uint32_t)name[0];
   1006 	rport = (u_int)name[1];
   1007 	laddr.s_addr = (uint32_t)name[2];
   1008 	lport = (u_int)name[3];
   1009 
   1010 	inb = in_pcblookup_connect(&tcbtable, raddr, rport, laddr, lport);
   1011 	if (inb) {
   1012 		struct socket *sockp = inb->inp_socket;
   1013 		if (sockp)
   1014 			uid = sockp->so_uid;
   1015 		else
   1016 			return ESRCH;
   1017 	} else
   1018 		return ESRCH;
   1019 
   1020 	if ((error = copyout(&uid, oldp, sizeof(uid))) != 0)
   1021 		return error;
   1022 
   1023 	return 0;
   1024 }
   1025