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udp6_usrreq.c revision 1.40
      1 /*	$NetBSD: udp6_usrreq.c,v 1.40 2001/02/11 06:49:53 itojun Exp $	*/
      2 /*	$KAME: udp6_usrreq.c,v 1.84 2001/02/07 07:38:25 itojun Exp $	*/
      3 
      4 /*
      5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      6  * All rights reserved.
      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 project nor the names of its contributors
     17  *    may be used to endorse or promote products derived from this software
     18  *    without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     30  * SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * Copyright (c) 1982, 1986, 1989, 1993
     35  *	The Regents of the University of California.  All rights reserved.
     36  *
     37  * Redistribution and use in source and binary forms, with or without
     38  * modification, are permitted provided that the following conditions
     39  * are met:
     40  * 1. Redistributions of source code must retain the above copyright
     41  *    notice, this list of conditions and the following disclaimer.
     42  * 2. Redistributions in binary form must reproduce the above copyright
     43  *    notice, this list of conditions and the following disclaimer in the
     44  *    documentation and/or other materials provided with the distribution.
     45  * 3. All advertising materials mentioning features or use of this software
     46  *    must display the following acknowledgement:
     47  *	This product includes software developed by the University of
     48  *	California, Berkeley and its contributors.
     49  * 4. Neither the name of the University nor the names of its contributors
     50  *    may be used to endorse or promote products derived from this software
     51  *    without specific prior written permission.
     52  *
     53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     63  * SUCH DAMAGE.
     64  *
     65  *	@(#)udp_var.h	8.1 (Berkeley) 6/10/93
     66  */
     67 
     68 #include "opt_ipsec.h"
     69 
     70 #include <sys/param.h>
     71 #include <sys/malloc.h>
     72 #include <sys/mbuf.h>
     73 #include <sys/protosw.h>
     74 #include <sys/socket.h>
     75 #include <sys/socketvar.h>
     76 #include <sys/errno.h>
     77 #include <sys/stat.h>
     78 #include <sys/systm.h>
     79 #include <sys/proc.h>
     80 #include <sys/syslog.h>
     81 
     82 #include <net/if.h>
     83 #include <net/route.h>
     84 #include <net/if_types.h>
     85 
     86 #include <netinet/in.h>
     87 #include <netinet/in_var.h>
     88 #include <netinet/in_systm.h>
     89 #include <netinet/ip.h>
     90 #include <netinet/ip_var.h>
     91 #include <netinet/in_pcb.h>
     92 #include <netinet/udp.h>
     93 #include <netinet/udp_var.h>
     94 #include <netinet/ip6.h>
     95 #include <netinet6/ip6_var.h>
     96 #include <netinet6/in6_pcb.h>
     97 #include <netinet/icmp6.h>
     98 #include <netinet6/udp6_var.h>
     99 #include <netinet6/ip6protosw.h>
    100 
    101 #ifdef IPSEC
    102 #include <netinet6/ipsec.h>
    103 #endif /*IPSEC*/
    104 
    105 #include "faith.h"
    106 
    107 /*
    108  * UDP protocol inplementation.
    109  * Per RFC 768, August, 1980.
    110  */
    111 
    112 struct	in6pcb *udp6_last_in6pcb = &udb6;
    113 
    114 #ifdef UDP6
    115 static	int in6_mcmatch __P((struct in6pcb *, struct in6_addr *, struct ifnet *));
    116 #endif
    117 static	void udp6_detach __P((struct in6pcb *));
    118 static	void udp6_notify __P((struct in6pcb *, int));
    119 
    120 void
    121 udp6_init()
    122 {
    123 	udb6.in6p_next = udb6.in6p_prev = &udb6;
    124 }
    125 
    126 #ifdef UDP6
    127 static int
    128 in6_mcmatch(in6p, ia6, ifp)
    129 	struct in6pcb *in6p;
    130 	struct in6_addr *ia6;
    131 	struct ifnet *ifp;
    132 {
    133 	struct ip6_moptions *im6o = in6p->in6p_moptions;
    134 	struct in6_multi_mship *imm;
    135 
    136 	if (im6o == NULL)
    137 		return 0;
    138 
    139 	for (imm = im6o->im6o_memberships.lh_first; imm != NULL;
    140 	     imm = imm->i6mm_chain.le_next) {
    141 		if ((ifp == NULL ||
    142 		     imm->i6mm_maddr->in6m_ifp == ifp) &&
    143 		    IN6_ARE_ADDR_EQUAL(&imm->i6mm_maddr->in6m_addr,
    144 				       ia6))
    145 			return 1;
    146 	}
    147 	return 0;
    148 }
    149 
    150 int
    151 udp6_input(mp, offp, proto)
    152 	struct mbuf **mp;
    153 	int *offp, proto;
    154 {
    155 	struct mbuf *m = *mp;
    156 	struct ip6_hdr *ip6;
    157 	struct udphdr *uh;
    158 	struct in6pcb *in6p;
    159 	struct	mbuf *opts = 0;
    160 	int off = *offp;
    161 	u_int32_t plen, ulen;
    162 	struct sockaddr_in6 udp_in6;
    163 
    164 #if defined(NFAITH) && 0 < NFAITH
    165 	if (m->m_pkthdr.rcvif) {
    166 		if (m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
    167 			/* send icmp6 host unreach? */
    168 			m_freem(m);
    169 			return IPPROTO_DONE;
    170 		}
    171 	}
    172 #endif
    173 	udp6stat.udp6s_ipackets++;
    174 
    175 	ip6 = mtod(m, struct ip6_hdr *);
    176 	/* check for jumbogram is done in ip6_input.  we can trust pkthdr.len */
    177 	plen = m->m_pkthdr.len - off;
    178 #ifndef PULLDOWN_TEST
    179 	IP6_EXTHDR_CHECK(m, off, sizeof(struct udphdr), IPPROTO_DONE);
    180 	uh = (struct udphdr *)((caddr_t)ip6 + off);
    181 #else
    182 	IP6_EXTHDR_GET(uh, struct udphdr *, m, off, sizeof(struct udphdr));
    183 	if (uh == NULL) {
    184 		udp6stat.udp6s_hdrops++;
    185 		return IPPROTO_DONE;
    186 	}
    187 #endif
    188 	ulen = ntohs((u_short)uh->uh_ulen);
    189 	/*
    190 	 * RFC2675 section 4: jumbograms will have 0 in the UDP header field,
    191 	 * iff payload length > 0xffff.
    192 	 */
    193 	if (ulen == 0 && plen > 0xffff)
    194 		ulen = plen;
    195 
    196 	if (plen != ulen) {
    197 		udp6stat.udp6s_badlen++;
    198 		goto bad;
    199 	}
    200 
    201 	/* destination port of 0 is illegal, based on RFC768. */
    202 	if (uh->uh_dport == 0)
    203 		goto bad;
    204 
    205 	/* Be proactive about malicious use of IPv4 mapped address */
    206 	if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
    207 	    IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
    208 		/* XXX stat */
    209 		goto bad;
    210 	}
    211 
    212 	/*
    213 	 * Checksum extended UDP header and data.
    214 	 */
    215 	if (uh->uh_sum == 0)
    216 		udp6stat.udp6s_nosum++;
    217 	else if (in6_cksum(m, IPPROTO_UDP, off, ulen) != 0) {
    218 		udp6stat.udp6s_badsum++;
    219 		goto bad;
    220 	}
    221 
    222 	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
    223 		struct	in6pcb *last;
    224 
    225 		/*
    226 		 * Deliver a multicast datagram to all sockets
    227 		 * for which the local and remote addresses and ports match
    228 		 * those of the incoming datagram.  This allows more than
    229 		 * one process to receive multicasts on the same port.
    230 		 * (This really ought to be done for unicast datagrams as
    231 		 * well, but that would cause problems with existing
    232 		 * applications that open both address-specific sockets and
    233 		 * a wildcard socket listening to the same port -- they would
    234 		 * end up receiving duplicates of every unicast datagram.
    235 		 * Those applications open the multiple sockets to overcome an
    236 		 * inadequacy of the UDP socket interface, but for backwards
    237 		 * compatibility we avoid the problem here rather than
    238 		 * fixing the interface.  Maybe 4.5BSD will remedy this?)
    239 		 */
    240 
    241 		/*
    242 		 * In a case that laddr should be set to the link-local
    243 		 * address (this happens in RIPng), the multicast address
    244 		 * specified in the received packet does not match with
    245 		 * laddr. To cure this situation, the matching is relaxed
    246 		 * if the receiving interface is the same as one specified
    247 		 * in the socket and if the destination multicast address
    248 		 * matches one of the multicast groups specified in the socket.
    249 		 */
    250 
    251 		/*
    252 		 * Construct sockaddr format source address.
    253 		 */
    254 		bzero(&udp_in6, sizeof(udp_in6));
    255 		udp_in6.sin6_len = sizeof(struct sockaddr_in6);
    256 		udp_in6.sin6_family = AF_INET6;
    257 		udp_in6.sin6_port = uh->uh_sport;
    258 #if 0 /*XXX inbound flowinfo */
    259 		udp_in6.sin6_flowinfo = ip6->ip6_flow & IPV6_FLOWINFO_MASK;
    260 #endif
    261 		/* KAME hack: recover scopeid */
    262 		(void)in6_recoverscope(&udp_in6, &ip6->ip6_src,
    263 		    m->m_pkthdr.rcvif);
    264 
    265 		/*
    266 		 * KAME note: usually we drop udphdr from mbuf here.
    267 		 * We need udphdr for IPsec processing so we do that later.
    268 		 */
    269 
    270 		/*
    271 		 * Locate pcb(s) for datagram.
    272 		 * (Algorithm copied from raw_intr().)
    273 		 */
    274 		last = NULL;
    275 		for (in6p = udb6.in6p_next;
    276 		     in6p != &udb6;
    277 		     in6p = in6p->in6p_next) {
    278 			if (in6p->in6p_lport != uh->uh_dport)
    279 				continue;
    280 			if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr)) {
    281 				if (!IN6_ARE_ADDR_EQUAL(&in6p->in6p_laddr,
    282 							&ip6->ip6_dst) &&
    283 				    !in6_mcmatch(in6p, &ip6->ip6_dst,
    284 						 m->m_pkthdr.rcvif))
    285 					continue;
    286 			}
    287 			if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
    288 				if (!IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr,
    289 							&ip6->ip6_src) ||
    290 				   in6p->in6p_fport != uh->uh_sport)
    291 					continue;
    292 			}
    293 
    294 			if (last != NULL) {
    295 				struct	mbuf *n;
    296 
    297 #ifdef IPSEC
    298 				/*
    299 				 * Check AH/ESP integrity.
    300 				 */
    301 				if (ipsec6_in_reject(m, last)) {
    302 					ipsec6stat.in_polvio++;
    303 					/* do not inject data into pcb */
    304 				} else
    305 #endif /*IPSEC*/
    306 				if ((n = m_copy(m, 0, M_COPYALL)) != NULL) {
    307 					/*
    308 					 * KAME NOTE: do not
    309 					 * m_copy(m, offset, ...) above.
    310 					 * sbappendaddr() expects M_PKTHDR,
    311 					 * and m_copy() will copy M_PKTHDR
    312 					 * only if offset is 0.
    313 					 */
    314 					if (last->in6p_flags & IN6P_CONTROLOPTS
    315 					 || last->in6p_socket->so_options & SO_TIMESTAMP) {
    316 						ip6_savecontrol(last, &opts,
    317 								ip6, n);
    318 					}
    319 
    320 					m_adj(n, off + sizeof(struct udphdr));
    321 					if (sbappendaddr(&last->in6p_socket->so_rcv,
    322 							(struct sockaddr *)&udp_in6,
    323 							n, opts) == 0) {
    324 						m_freem(n);
    325 						if (opts)
    326 							m_freem(opts);
    327 						udp6stat.udp6s_fullsock++;
    328 					} else
    329 						sorwakeup(last->in6p_socket);
    330 					opts = 0;
    331 				}
    332 			}
    333 			last = in6p;
    334 			/*
    335 			 * Don't look for additional matches if this one does
    336 			 * not have either the SO_REUSEPORT or SO_REUSEADDR
    337 			 * socket options set.  This heuristic avoids searching
    338 			 * through all pcbs in the common case of a non-shared
    339 			 * port.  It assumes that an application will never
    340 			 * clear these options after setting them.
    341 			 */
    342 			if ((last->in6p_socket->so_options &
    343 			     (SO_REUSEPORT|SO_REUSEADDR)) == 0)
    344 				break;
    345 		}
    346 
    347 		if (last == NULL) {
    348 			/*
    349 			 * No matching pcb found; discard datagram.
    350 			 * (No need to send an ICMP Port Unreachable
    351 			 * for a broadcast or multicast datgram.)
    352 			 */
    353 			udp6stat.udp6s_noport++;
    354 			udp6stat.udp6s_noportmcast++;
    355 			goto bad;
    356 		}
    357 #ifdef IPSEC
    358 		/*
    359 		 * Check AH/ESP integrity.
    360 		 */
    361 		if (last != NULL && ipsec6_in_reject(m, last)) {
    362 			ipsec6stat.in_polvio++;
    363 			goto bad;
    364 		}
    365 #endif /*IPSEC*/
    366 		if (last->in6p_flags & IN6P_CONTROLOPTS
    367 		 || last->in6p_socket->so_options & SO_TIMESTAMP) {
    368 			ip6_savecontrol(last, &opts, ip6, m);
    369 		}
    370 
    371 		m_adj(m, off + sizeof(struct udphdr));
    372 		if (sbappendaddr(&last->in6p_socket->so_rcv,
    373 				(struct sockaddr *)&udp_in6,
    374 				m, opts) == 0) {
    375 			udp6stat.udp6s_fullsock++;
    376 			goto bad;
    377 		}
    378 		sorwakeup(last->in6p_socket);
    379 		return IPPROTO_DONE;
    380 	}
    381 	/*
    382 	 * Locate pcb for datagram.
    383 	 */
    384 	in6p = udp6_last_in6pcb;
    385 	if (in6p->in6p_lport != uh->uh_dport ||
    386 	   in6p->in6p_fport != uh->uh_sport ||
    387 	   !IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr, &ip6->ip6_src) ||
    388 	   !IN6_ARE_ADDR_EQUAL(&in6p->in6p_laddr, &ip6->ip6_dst)) {
    389 		in6p = in6_pcblookup(&udb6,
    390 				     &ip6->ip6_src, uh->uh_sport,
    391 				     &ip6->ip6_dst, uh->uh_dport,
    392 				     IN6PLOOKUP_WILDCARD);
    393 		if (in6p)
    394 			udp6_last_in6pcb = in6p;
    395 		udp6stat.udp6ps_pcbcachemiss++;
    396 	}
    397 	if (in6p == 0) {
    398 		udp6stat.udp6s_noport++;
    399 		if (m->m_flags & M_MCAST) {
    400 			printf("UDP6: M_MCAST is set in a unicast packet.\n");
    401 			udp6stat.udp6s_noportmcast++;
    402 			goto bad;
    403 		}
    404 		icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOPORT, 0);
    405 		return IPPROTO_DONE;
    406 	}
    407 #ifdef IPSEC
    408 	/*
    409 	 * Check AH/ESP integrity.
    410 	 */
    411 	if (in6p != NULL && ipsec6_in_reject(m, in6p)) {
    412 		ipsec6stat.in_polvio++;
    413 		goto bad;
    414 	}
    415 #endif /*IPSEC*/
    416 
    417 	/*
    418 	 * Construct sockaddr format source address.
    419 	 * Stuff source address and datagram in user buffer.
    420 	 */
    421 	bzero(&udp_in6, sizeof(udp_in6));
    422 	udp_in6.sin6_len = sizeof(struct sockaddr_in6);
    423 	udp_in6.sin6_family = AF_INET6;
    424 	udp_in6.sin6_port = uh->uh_sport;
    425 	/* KAME hack: recover scopeid */
    426 	(void)in6_recoverscope(&udp_in6, &ip6->ip6_src, m->m_pkthdr.rcvif);
    427 	if (in6p->in6p_flags & IN6P_CONTROLOPTS
    428 	 || in6p->in6p_socket->so_options & SO_TIMESTAMP) {
    429 		ip6_savecontrol(in6p, &opts, ip6, m);
    430 	}
    431 
    432 	m_adj(m, off + sizeof(struct udphdr));
    433 	if (sbappendaddr(&in6p->in6p_socket->so_rcv,
    434 			(struct sockaddr *)&udp_in6,
    435 			m, opts) == 0) {
    436 		udp6stat.udp6s_fullsock++;
    437 		goto bad;
    438 	}
    439 	sorwakeup(in6p->in6p_socket);
    440 	return IPPROTO_DONE;
    441 bad:
    442 	if (m)
    443 		m_freem(m);
    444 	if (opts)
    445 		m_freem(opts);
    446 	return IPPROTO_DONE;
    447 }
    448 #endif
    449 
    450 /*
    451  * Notify a udp user of an asynchronous error;
    452  * just wake up so that he can collect error status.
    453  */
    454 static	void
    455 udp6_notify(in6p, errno)
    456 	struct in6pcb *in6p;
    457 	int errno;
    458 {
    459 	in6p->in6p_socket->so_error = errno;
    460 	sorwakeup(in6p->in6p_socket);
    461 	sowwakeup(in6p->in6p_socket);
    462 }
    463 
    464 void
    465 udp6_ctlinput(cmd, sa, d)
    466 	int cmd;
    467 	struct sockaddr *sa;
    468 	void *d;
    469 {
    470 	struct udphdr uh;
    471 	struct ip6_hdr *ip6;
    472 	struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa;
    473 	struct mbuf *m;
    474 	int off;
    475 	void *cmdarg;
    476 	struct ip6ctlparam *ip6cp = NULL;
    477 	const struct sockaddr_in6 *sa6_src = NULL;
    478 	void (*notify) __P((struct in6pcb *, int)) = udp6_notify;
    479 	struct udp_portonly {
    480 		u_int16_t uh_sport;
    481 		u_int16_t uh_dport;
    482 	} *uhp;
    483 
    484 	if (sa->sa_family != AF_INET6 ||
    485 	    sa->sa_len != sizeof(struct sockaddr_in6))
    486 		return;
    487 
    488 	if ((unsigned)cmd >= PRC_NCMDS)
    489 		return;
    490 	if (PRC_IS_REDIRECT(cmd))
    491 		notify = in6_rtchange, d = NULL;
    492 	else if (cmd == PRC_HOSTDEAD)
    493 		d = NULL;
    494 	else if (cmd == PRC_MSGSIZE)
    495 		; /* special code is present, see below */
    496 	else if (inet6ctlerrmap[cmd] == 0)
    497 		return;
    498 
    499 	/* if the parameter is from icmp6, decode it. */
    500 	if (d != NULL) {
    501 		ip6cp = (struct ip6ctlparam *)d;
    502 		m = ip6cp->ip6c_m;
    503 		ip6 = ip6cp->ip6c_ip6;
    504 		off = ip6cp->ip6c_off;
    505 		cmdarg = ip6cp->ip6c_cmdarg;
    506 		sa6_src = ip6cp->ip6c_src;
    507 	} else {
    508 		m = NULL;
    509 		ip6 = NULL;
    510 		cmdarg = NULL;
    511 		sa6_src = &sa6_any;
    512 	}
    513 
    514 	if (ip6) {
    515 		/*
    516 		 * XXX: We assume that when IPV6 is non NULL,
    517 		 * M and OFF are valid.
    518 		 */
    519 
    520 		/* check if we can safely examine src and dst ports */
    521 		if (m->m_pkthdr.len < off + sizeof(*uhp))
    522 			return;
    523 
    524 		bzero(&uh, sizeof(uh));
    525 		m_copydata(m, off, sizeof(*uhp), (caddr_t)&uh);
    526 
    527 		if (cmd == PRC_MSGSIZE) {
    528 			int valid = 0;
    529 
    530 			/*
    531 			 * Check to see if we have a valid UDP socket
    532 			 * corresponding to the address in the ICMPv6 message
    533 			 * payload.
    534 			 */
    535 			if (in6_pcblookup_connect(&udb6, &sa6->sin6_addr,
    536 			    uh.uh_dport, (struct in6_addr *)&sa6_src->sin6_addr,
    537 			    uh.uh_sport, 0))
    538 				valid++;
    539 #if 0
    540 			/*
    541 			 * As the use of sendto(2) is fairly popular,
    542 			 * we may want to allow non-connected pcb too.
    543 			 * But it could be too weak against attacks...
    544 			 * We should at least check if the local address (= s)
    545 			 * is really ours.
    546 			 */
    547 			else if (in6_pcblookup_bind(&udb6, &sa6->sin6_addr,
    548 						    uh.uh_dport, 0))
    549 				valid++;
    550 #endif
    551 
    552 			/*
    553 			 * Depending on the value of "valid" and routing table
    554 			 * size (mtudisc_{hi,lo}wat), we will:
    555 			 * - recalcurate the new MTU and create the
    556 			 *   corresponding routing entry, or
    557 			 * - ignore the MTU change notification.
    558 			 */
    559 			icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
    560 
    561 			/*
    562 			 * regardless of if we called icmp6_mtudisc_update(),
    563 			 * we need to call in6_pcbnotify(), to notify path
    564 			 * MTU change to the userland (2292bis-02), because
    565 			 * some unconnected sockets may share the same
    566 			 * destination and want to know the path MTU.
    567 			 */
    568 		}
    569 
    570 		(void) in6_pcbnotify(&udb6, sa, uh.uh_dport,
    571 		    (struct sockaddr *)sa6_src, uh.uh_sport, cmd, cmdarg,
    572 		    notify);
    573 	} else {
    574 		(void) in6_pcbnotify(&udb6, sa, 0, (struct sockaddr *)sa6_src,
    575 		    0, cmd, cmdarg, notify);
    576 	}
    577 }
    578 
    579 extern	int udp6_sendspace;
    580 extern	int udp6_recvspace;
    581 
    582 int
    583 udp6_usrreq(so, req, m, addr6, control, p)
    584 	struct socket *so;
    585 	int req;
    586 	struct mbuf *m, *addr6, *control;
    587 	struct proc *p;
    588 {
    589 	struct	in6pcb *in6p = sotoin6pcb(so);
    590 	int	error = 0;
    591 	int	s;
    592 
    593 	/*
    594 	 * MAPPED_ADDR implementation info:
    595 	 *  Mapped addr support for PRU_CONTROL is not necessary.
    596 	 *  Because typical user of PRU_CONTROL is such as ifconfig,
    597 	 *  and they don't associate any addr to their socket.  Then
    598 	 *  socket family is only hint about the PRU_CONTROL'ed address
    599 	 *  family, especially when getting addrs from kernel.
    600 	 *  So AF_INET socket need to be used to control AF_INET addrs,
    601 	 *  and AF_INET6 socket for AF_INET6 addrs.
    602 	 */
    603 	if (req == PRU_CONTROL)
    604 		return(in6_control(so, (u_long)m, (caddr_t)addr6,
    605 				   (struct ifnet *)control, p));
    606 
    607 	if (req == PRU_PURGEIF) {
    608 		in6_purgeif((struct ifnet *)control);
    609 		in6_pcbpurgeif(&udb6, (struct ifnet *)control);
    610 		return (0);
    611 	}
    612 
    613 	if (in6p == NULL && req != PRU_ATTACH) {
    614 		error = EINVAL;
    615 		goto release;
    616 	}
    617 
    618 	switch (req) {
    619 	case PRU_ATTACH:
    620 		/*
    621 		 * MAPPED_ADDR implementation spec:
    622 		 *  Always attach for IPv6,
    623 		 *  and only when necessary for IPv4.
    624 		 */
    625 		if (in6p != NULL) {
    626 			error = EINVAL;
    627 			break;
    628 		}
    629 		s = splsoftnet();
    630 		error = in6_pcballoc(so, &udb6);
    631 		splx(s);
    632 		if (error)
    633 			break;
    634 		error = soreserve(so, udp6_sendspace, udp6_recvspace);
    635 		if (error)
    636 			break;
    637 		in6p = sotoin6pcb(so);
    638 		in6p->in6p_cksum = -1;	/* just to be sure */
    639 #ifdef IPSEC
    640 		error = ipsec_init_policy(so, &in6p->in6p_sp);
    641 		if (error != 0) {
    642 			in6_pcbdetach(in6p);
    643 			break;
    644 		}
    645 #endif /*IPSEC*/
    646 		break;
    647 
    648 	case PRU_DETACH:
    649 		udp6_detach(in6p);
    650 		break;
    651 
    652 	case PRU_BIND:
    653 		s = splsoftnet();
    654 		error = in6_pcbbind(in6p, addr6, p);
    655 		splx(s);
    656 		break;
    657 
    658 	case PRU_LISTEN:
    659 		error = EOPNOTSUPP;
    660 		break;
    661 
    662 	case PRU_CONNECT:
    663 		if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
    664 			error = EISCONN;
    665 			break;
    666 		}
    667 		s = splsoftnet();
    668 		error = in6_pcbconnect(in6p, addr6);
    669 		if (ip6_auto_flowlabel) {
    670 			in6p->in6p_flowinfo &= ~IPV6_FLOWLABEL_MASK;
    671 			in6p->in6p_flowinfo |=
    672 				(htonl(ip6_flow_seq++) & IPV6_FLOWLABEL_MASK);
    673 		}
    674 		splx(s);
    675 		if (error == 0)
    676 			soisconnected(so);
    677 		break;
    678 
    679 	case PRU_CONNECT2:
    680 		error = EOPNOTSUPP;
    681 		break;
    682 
    683 	case PRU_ACCEPT:
    684 		error = EOPNOTSUPP;
    685 		break;
    686 
    687 	case PRU_DISCONNECT:
    688 		if (IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
    689 			error = ENOTCONN;
    690 			break;
    691 		}
    692 		s = splsoftnet();
    693 		in6_pcbdisconnect(in6p);
    694 		bzero((caddr_t)&in6p->in6p_laddr, sizeof(in6p->in6p_laddr));
    695 		splx(s);
    696 		so->so_state &= ~SS_ISCONNECTED;		/* XXX */
    697 		break;
    698 
    699 	case PRU_SHUTDOWN:
    700 		socantsendmore(so);
    701 		break;
    702 
    703 	case PRU_SEND:
    704 		return(udp6_output(in6p, m, addr6, control, p));
    705 
    706 	case PRU_ABORT:
    707 		soisdisconnected(so);
    708 		udp6_detach(in6p);
    709 		break;
    710 
    711 	case PRU_SOCKADDR:
    712 		in6_setsockaddr(in6p, addr6);
    713 		break;
    714 
    715 	case PRU_PEERADDR:
    716 		in6_setpeeraddr(in6p, addr6);
    717 		break;
    718 
    719 	case PRU_SENSE:
    720 		/*
    721 		 * stat: don't bother with a blocksize
    722 		 */
    723 		return(0);
    724 
    725 	case PRU_SENDOOB:
    726 	case PRU_FASTTIMO:
    727 	case PRU_SLOWTIMO:
    728 	case PRU_PROTORCV:
    729 	case PRU_PROTOSEND:
    730 		error = EOPNOTSUPP;
    731 		break;
    732 
    733 	case PRU_RCVD:
    734 	case PRU_RCVOOB:
    735 		return(EOPNOTSUPP);	/* do not free mbuf's */
    736 
    737 	default:
    738 		panic("udp6_usrreq");
    739 	}
    740 
    741 release:
    742 	if (control) {
    743 		printf("udp control data unexpectedly retained\n");
    744 		m_freem(control);
    745 	}
    746 	if (m)
    747 		m_freem(m);
    748 	return(error);
    749 }
    750 
    751 static void
    752 udp6_detach(in6p)
    753 	struct in6pcb *in6p;
    754 {
    755 	int s = splsoftnet();
    756 
    757 	if (in6p == udp6_last_in6pcb)
    758 		udp6_last_in6pcb = &udb6;
    759 	in6_pcbdetach(in6p);
    760 	splx(s);
    761 }
    762 
    763 #include <uvm/uvm_extern.h>
    764 #include <sys/sysctl.h>
    765 
    766 int
    767 udp6_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
    768 	int *name;
    769 	u_int namelen;
    770 	void *oldp;
    771 	size_t *oldlenp;
    772 	void *newp;
    773 	size_t newlen;
    774 {
    775 	/* All sysctl names at this level are terminal. */
    776 	if (namelen != 1)
    777 		return ENOTDIR;
    778 
    779 	switch (name[0]) {
    780 
    781 	case UDP6CTL_SENDSPACE:
    782 		return sysctl_int(oldp, oldlenp, newp, newlen,
    783 		    &udp6_sendspace);
    784 	case UDP6CTL_RECVSPACE:
    785 		return sysctl_int(oldp, oldlenp, newp, newlen,
    786 		    &udp6_recvspace);
    787 	default:
    788 		return ENOPROTOOPT;
    789 	}
    790 	/* NOTREACHED */
    791 }
    792