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icmp6.c revision 1.35
      1 /*	$NetBSD: icmp6.c,v 1.35 2000/07/06 12:36:18 itojun Exp $	*/
      2 /*	$KAME: icmp6.c,v 1.120 2000/07/06 11:47:20 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, 1988, 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  *	@(#)ip_icmp.c	8.2 (Berkeley) 1/4/94
     66  */
     67 
     68 #include "opt_inet.h"
     69 #include "opt_ipsec.h"
     70 
     71 #include <sys/param.h>
     72 #include <sys/systm.h>
     73 #include <sys/malloc.h>
     74 #include <sys/mbuf.h>
     75 #include <sys/protosw.h>
     76 #include <sys/socket.h>
     77 #include <sys/socketvar.h>
     78 #include <sys/time.h>
     79 #include <sys/kernel.h>
     80 #include <sys/syslog.h>
     81 #include <sys/domain.h>
     82 
     83 #include <net/if.h>
     84 #include <net/route.h>
     85 #include <net/if_dl.h>
     86 #include <net/if_types.h>
     87 
     88 #include <netinet/in.h>
     89 #include <netinet/in_var.h>
     90 #include <netinet/ip6.h>
     91 #include <netinet6/ip6_var.h>
     92 #include <netinet/icmp6.h>
     93 #include <netinet6/mld6_var.h>
     94 #include <netinet6/in6_pcb.h>
     95 #include <netinet6/nd6.h>
     96 #include <netinet6/in6_ifattach.h>
     97 #include <netinet6/ip6protosw.h>
     98 
     99 
    100 #ifdef IPSEC
    101 #include <netinet6/ipsec.h>
    102 #include <netkey/key.h>
    103 #endif
    104 
    105 #include "faith.h"
    106 
    107 #include <net/net_osdep.h>
    108 
    109 extern struct domain inet6domain;
    110 
    111 struct icmp6stat icmp6stat;
    112 
    113 extern struct in6pcb rawin6pcb;
    114 extern struct timeval icmp6errratelim;
    115 static struct timeval icmp6errratelim_last;
    116 extern int icmp6errppslim;
    117 static int icmp6errpps_count = 0;
    118 extern int icmp6_nodeinfo;
    119 static struct rttimer_queue *icmp6_mtudisc_timeout_q = NULL;
    120 extern int pmtu_expire;
    121 
    122 static void icmp6_errcount __P((struct icmp6errstat *, int, int));
    123 static int icmp6_rip6_input __P((struct mbuf **, int));
    124 static void icmp6_mtudisc_update __P((struct in6_addr *, struct icmp6_hdr *,
    125 				      struct mbuf *));
    126 static int icmp6_ratelimit __P((const struct in6_addr *, const int, const int));
    127 static const char *icmp6_redirect_diag __P((struct in6_addr *,
    128 	struct in6_addr *, struct in6_addr *));
    129 static struct mbuf *ni6_input __P((struct mbuf *, int));
    130 static struct mbuf *ni6_nametodns __P((const char *, int, int));
    131 static int ni6_dnsmatch __P((const char *, int, const char *, int));
    132 static int ni6_addrs __P((struct icmp6_nodeinfo *, struct mbuf *,
    133 			  struct ifnet **));
    134 static int ni6_store_addrs __P((struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
    135 				struct ifnet *, int));
    136 static struct rtentry *icmp6_mtudisc_clone __P((struct sockaddr *));
    137 static void icmp6_mtudisc_timeout __P((struct rtentry *, struct rttimer *));
    138 
    139 #ifdef COMPAT_RFC1885
    140 static struct route_in6 icmp6_reflect_rt;
    141 #endif
    142 
    143 void
    144 icmp6_init()
    145 {
    146 	mld6_init();
    147 	icmp6_mtudisc_timeout_q = rt_timer_queue_create(pmtu_expire);
    148 }
    149 
    150 static void
    151 icmp6_errcount(stat, type, code)
    152 	struct icmp6errstat *stat;
    153 	int type, code;
    154 {
    155 	switch(type) {
    156 	case ICMP6_DST_UNREACH:
    157 		switch (code) {
    158 		case ICMP6_DST_UNREACH_NOROUTE:
    159 			stat->icp6errs_dst_unreach_noroute++;
    160 			return;
    161 		case ICMP6_DST_UNREACH_ADMIN:
    162 			stat->icp6errs_dst_unreach_admin++;
    163 			return;
    164 		case ICMP6_DST_UNREACH_BEYONDSCOPE:
    165 			stat->icp6errs_dst_unreach_beyondscope++;
    166 			return;
    167 		case ICMP6_DST_UNREACH_ADDR:
    168 			stat->icp6errs_dst_unreach_addr++;
    169 			return;
    170 		case ICMP6_DST_UNREACH_NOPORT:
    171 			stat->icp6errs_dst_unreach_noport++;
    172 			return;
    173 		}
    174 		break;
    175 	case ICMP6_PACKET_TOO_BIG:
    176 		stat->icp6errs_packet_too_big++;
    177 		return;
    178 	case ICMP6_TIME_EXCEEDED:
    179 		switch(code) {
    180 		case ICMP6_TIME_EXCEED_TRANSIT:
    181 			stat->icp6errs_time_exceed_transit++;
    182 			return;
    183 		case ICMP6_TIME_EXCEED_REASSEMBLY:
    184 			stat->icp6errs_time_exceed_reassembly++;
    185 			return;
    186 		}
    187 		break;
    188 	case ICMP6_PARAM_PROB:
    189 		switch(code) {
    190 		case ICMP6_PARAMPROB_HEADER:
    191 			stat->icp6errs_paramprob_header++;
    192 			return;
    193 		case ICMP6_PARAMPROB_NEXTHEADER:
    194 			stat->icp6errs_paramprob_nextheader++;
    195 			return;
    196 		case ICMP6_PARAMPROB_OPTION:
    197 			stat->icp6errs_paramprob_option++;
    198 			return;
    199 		}
    200 		break;
    201 	case ND_REDIRECT:
    202 		stat->icp6errs_redirect++;
    203 		return;
    204 	}
    205 	stat->icp6errs_unknown++;
    206 }
    207 
    208 /*
    209  * Generate an error packet of type error in response to bad IP6 packet.
    210  */
    211 void
    212 icmp6_error(m, type, code, param)
    213 	struct mbuf *m;
    214 	int type, code, param;
    215 {
    216 	struct ip6_hdr *oip6, *nip6;
    217 	struct icmp6_hdr *icmp6;
    218 	u_int preplen;
    219 	int off;
    220 	int nxt;
    221 
    222 	icmp6stat.icp6s_error++;
    223 
    224 	/* count per-type-code statistics */
    225 	icmp6_errcount(&icmp6stat.icp6s_outerrhist, type, code);
    226 
    227 	if (m->m_flags & M_DECRYPTED) {
    228 		icmp6stat.icp6s_canterror++;
    229 		goto freeit;
    230 	}
    231 
    232 #ifndef PULLDOWN_TEST
    233 	IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), );
    234 #else
    235 	if (m->m_len < sizeof(struct ip6_hdr)) {
    236 		m = m_pullup(m, sizeof(struct ip6_hdr));
    237 		if (m == NULL)
    238 			return;
    239 	}
    240 #endif
    241 	oip6 = mtod(m, struct ip6_hdr *);
    242 
    243 	/*
    244 	 * Multicast destination check. For unrecognized option errors,
    245 	 * this check has already done in ip6_unknown_opt(), so we can
    246 	 * check only for other errors.
    247 	 */
    248 	if ((m->m_flags & (M_BCAST|M_MCAST) ||
    249 	     IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
    250 	    (type != ICMP6_PACKET_TOO_BIG &&
    251 	     (type != ICMP6_PARAM_PROB ||
    252 	      code != ICMP6_PARAMPROB_OPTION)))
    253 		goto freeit;
    254 
    255 	/* Source address check. XXX: the case of anycast source? */
    256 	if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
    257 	    IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
    258 		goto freeit;
    259 
    260 	/*
    261 	 * If we are about to send ICMPv6 against ICMPv6 error/redirect,
    262 	 * don't do it.
    263 	 */
    264 	nxt = -1;
    265 	off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
    266 	if (off >= 0 && nxt == IPPROTO_ICMPV6) {
    267 		struct icmp6_hdr *icp;
    268 
    269 #ifndef PULLDOWN_TEST
    270 		IP6_EXTHDR_CHECK(m, 0, off + sizeof(struct icmp6_hdr), );
    271 		icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
    272 #else
    273 		IP6_EXTHDR_GET(icp, struct icmp6_hdr *, m, off,
    274 			sizeof(*icp));
    275 		if (icp == NULL) {
    276 			icmp6stat.icp6s_tooshort++;
    277 			return;
    278 		}
    279 #endif
    280 		if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
    281 		    icp->icmp6_type == ND_REDIRECT) {
    282 			/*
    283 			 * ICMPv6 error
    284 			 * Special case: for redirect (which is
    285 			 * informational) we must not send icmp6 error.
    286 			 */
    287 			icmp6stat.icp6s_canterror++;
    288 			goto freeit;
    289 		} else {
    290 			/* ICMPv6 informational - send the error */
    291 		}
    292 	} else {
    293 		/* non-ICMPv6 - send the error */
    294 	}
    295 
    296 	oip6 = mtod(m, struct ip6_hdr *); /* adjust pointer */
    297 
    298 	/* Finally, do rate limitation check. */
    299 	if (icmp6_ratelimit(&oip6->ip6_src, type, code)) {
    300 		icmp6stat.icp6s_toofreq++;
    301 		goto freeit;
    302 	}
    303 
    304 	/*
    305 	 * OK, ICMP6 can be generated.
    306 	 */
    307 
    308 	if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
    309 		m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
    310 
    311 	preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
    312 	M_PREPEND(m, preplen, M_DONTWAIT);
    313 	if (m && m->m_len < preplen)
    314 		m = m_pullup(m, preplen);
    315 	if (m == NULL) {
    316 		printf("ENOBUFS in icmp6_error %d\n", __LINE__);
    317 		return;
    318 	}
    319 
    320 	nip6 = mtod(m, struct ip6_hdr *);
    321 	nip6->ip6_src  = oip6->ip6_src;
    322 	nip6->ip6_dst  = oip6->ip6_dst;
    323 
    324 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
    325 		oip6->ip6_src.s6_addr16[1] = 0;
    326 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
    327 		oip6->ip6_dst.s6_addr16[1] = 0;
    328 
    329 	icmp6 = (struct icmp6_hdr *)(nip6 + 1);
    330 	icmp6->icmp6_type = type;
    331 	icmp6->icmp6_code = code;
    332 	icmp6->icmp6_pptr = htonl((u_int32_t)param);
    333 
    334 	icmp6stat.icp6s_outhist[type]++;
    335 	icmp6_reflect(m, sizeof(struct ip6_hdr)); /*header order: IPv6 - ICMPv6*/
    336 
    337 	return;
    338 
    339   freeit:
    340 	/*
    341 	 * If we can't tell wheter or not we can generate ICMP6, free it.
    342 	 */
    343 	m_freem(m);
    344 }
    345 
    346 /*
    347  * Process a received ICMP6 message.
    348  */
    349 int
    350 icmp6_input(mp, offp, proto)
    351 	struct mbuf **mp;
    352 	int *offp, proto;
    353 {
    354 	struct mbuf *m = *mp, *n;
    355 	struct ip6_hdr *ip6, *nip6;
    356 	struct icmp6_hdr *icmp6, *nicmp6;
    357 	int off = *offp;
    358 	int icmp6len = m->m_pkthdr.len - *offp;
    359 	int code, sum, noff;
    360 	struct sockaddr_in6 icmp6src;
    361 
    362 #ifndef PULLDOWN_TEST
    363 	IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_hdr), IPPROTO_DONE);
    364 	/* m might change if M_LOOP. So, call mtod after this */
    365 #endif
    366 
    367 	/*
    368 	 * Locate icmp6 structure in mbuf, and check
    369 	 * that not corrupted and of at least minimum length
    370 	 */
    371 
    372 	ip6 = mtod(m, struct ip6_hdr *);
    373 	if (icmp6len < sizeof(struct icmp6_hdr)) {
    374 		icmp6stat.icp6s_tooshort++;
    375 		goto freeit;
    376 	}
    377 
    378 	/*
    379 	 * calculate the checksum
    380 	 */
    381 #ifndef PULLDOWN_TEST
    382 	icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
    383 #else
    384 	IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
    385 	if (icmp6 == NULL) {
    386 		icmp6stat.icp6s_tooshort++;
    387 		return IPPROTO_DONE;
    388 	}
    389 #endif
    390 	code = icmp6->icmp6_code;
    391 
    392 	if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
    393 		log(LOG_ERR,
    394 		    "ICMP6 checksum error(%d|%x) %s\n",
    395 		    icmp6->icmp6_type,
    396 		    sum,
    397 		    ip6_sprintf(&ip6->ip6_src));
    398 		icmp6stat.icp6s_checksum++;
    399 		goto freeit;
    400 	}
    401 
    402 #if defined(NFAITH) && 0 < NFAITH
    403 	if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
    404 		/*
    405 		 * Deliver very specific ICMP6 type only.
    406 		 * This is important to deilver TOOBIG.  Otherwise PMTUD
    407 		 * will not work.
    408 		 */
    409 		switch (icmp6->icmp6_type) {
    410 		case ICMP6_DST_UNREACH:
    411 		case ICMP6_PACKET_TOO_BIG:
    412 		case ICMP6_TIME_EXCEEDED:
    413 			break;
    414 		default:
    415 			goto freeit;
    416 		}
    417 	}
    418 #endif
    419 
    420 #ifdef IPSEC
    421 	/* drop it if it does not match the default policy */
    422 	if (ipsec6_in_reject(m, NULL)) {
    423 		ipsecstat.in_polvio++;
    424 		goto freeit;
    425 	}
    426 #endif
    427 
    428 	icmp6stat.icp6s_inhist[icmp6->icmp6_type]++;
    429 	icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_msg);
    430 	if (icmp6->icmp6_type < ICMP6_INFOMSG_MASK)
    431 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_error);
    432 
    433 	switch (icmp6->icmp6_type) {
    434 
    435 	case ICMP6_DST_UNREACH:
    436 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_dstunreach);
    437 		switch (code) {
    438 		case ICMP6_DST_UNREACH_NOROUTE:
    439 			code = PRC_UNREACH_NET;
    440 			break;
    441 		case ICMP6_DST_UNREACH_ADMIN:
    442 			icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_adminprohib);
    443 			code = PRC_UNREACH_PROTOCOL; /* is this a good code? */
    444 			break;
    445 		case ICMP6_DST_UNREACH_ADDR:
    446 			code = PRC_HOSTDEAD;
    447 			break;
    448 #ifdef COMPAT_RFC1885
    449 		case ICMP6_DST_UNREACH_NOTNEIGHBOR:
    450 			code = PRC_UNREACH_SRCFAIL;
    451 			break;
    452 #else
    453 		case ICMP6_DST_UNREACH_BEYONDSCOPE:
    454 			/* I mean "source address was incorrect." */
    455 			code = PRC_PARAMPROB;
    456 			break;
    457 #endif
    458 		case ICMP6_DST_UNREACH_NOPORT:
    459 			code = PRC_UNREACH_PORT;
    460 			break;
    461 		default:
    462 			goto badcode;
    463 		}
    464 		goto deliver;
    465 		break;
    466 
    467 	case ICMP6_PACKET_TOO_BIG:
    468 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_pkttoobig);
    469 		if (code != 0)
    470 			goto badcode;
    471 
    472 		code = PRC_MSGSIZE;
    473 
    474 		/*
    475 		 * Updating the path MTU will be done after examining
    476 		 * intermediate extension headers.
    477 		 */
    478 		goto deliver;
    479 		break;
    480 
    481 	case ICMP6_TIME_EXCEEDED:
    482 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_timeexceed);
    483 		switch (code) {
    484 		case ICMP6_TIME_EXCEED_TRANSIT:
    485 		case ICMP6_TIME_EXCEED_REASSEMBLY:
    486 			code += PRC_TIMXCEED_INTRANS;
    487 			break;
    488 		default:
    489 			goto badcode;
    490 		}
    491 		goto deliver;
    492 		break;
    493 
    494 	case ICMP6_PARAM_PROB:
    495 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_paramprob);
    496 		switch (code) {
    497 		case ICMP6_PARAMPROB_NEXTHEADER:
    498 			code = PRC_UNREACH_PROTOCOL;
    499 			break;
    500 		case ICMP6_PARAMPROB_HEADER:
    501 		case ICMP6_PARAMPROB_OPTION:
    502 			code = PRC_PARAMPROB;
    503 			break;
    504 		default:
    505 			goto badcode;
    506 		}
    507 		goto deliver;
    508 		break;
    509 
    510 	case ICMP6_ECHO_REQUEST:
    511 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_echo);
    512 		if (code != 0)
    513 			goto badcode;
    514 		if ((n = m_copy(m, 0, M_COPYALL)) == NULL) {
    515 			/* Give up remote */
    516 			break;
    517 		}
    518 		if ((n->m_flags & M_EXT) != 0
    519 		 || n->m_len < off + sizeof(struct icmp6_hdr)) {
    520 			struct mbuf *n0 = n;
    521 			const int maxlen = sizeof(*nip6) + sizeof(*nicmp6);
    522 
    523 			/*
    524 			 * Prepare an internal mbuf. m_pullup() doesn't
    525 			 * always copy the length we specified.
    526 			 */
    527 			if (maxlen >= MCLBYTES) {
    528 #ifdef DIAGNOSTIC
    529 				printf("MCLBYTES too small\n");
    530 #endif
    531 				/* Give up remote */
    532 				m_freem(n0);
    533 				break;
    534 			}
    535 			MGETHDR(n, M_DONTWAIT, n0->m_type);
    536 			if (n && maxlen >= MHLEN) {
    537 				MCLGET(n, M_DONTWAIT);
    538 				if ((n->m_flags & M_EXT) == 0) {
    539 					m_free(n);
    540 					n = NULL;
    541 				}
    542 			}
    543 			if (n == NULL) {
    544 				/* Give up remote */
    545 				m_freem(n0);
    546 				break;
    547 			}
    548 			M_COPY_PKTHDR(n, n0);
    549 			/*
    550 			 * Copy IPv6 and ICMPv6 only.
    551 			 */
    552 			nip6 = mtod(n, struct ip6_hdr *);
    553 			bcopy(ip6, nip6, sizeof(struct ip6_hdr));
    554 			nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
    555 			bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
    556 			noff = sizeof(struct ip6_hdr);
    557 			n->m_pkthdr.len = n->m_len =
    558 				noff + sizeof(struct icmp6_hdr);
    559 			/*
    560 			 * Adjust mbuf. ip6_plen will be adjusted in
    561 			 * ip6_output().
    562 			 */
    563 			m_adj(n0, off + sizeof(struct icmp6_hdr));
    564 			n->m_pkthdr.len += n0->m_pkthdr.len;
    565 			n->m_next = n0;
    566 			n0->m_flags &= ~M_PKTHDR;
    567 		} else {
    568 			nip6 = mtod(n, struct ip6_hdr *);
    569 			nicmp6 = (struct icmp6_hdr *)((caddr_t)nip6 + off);
    570 			noff = off;
    571 		}
    572 		nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
    573 		nicmp6->icmp6_code = 0;
    574 		if (n) {
    575 			icmp6stat.icp6s_reflect++;
    576 			icmp6stat.icp6s_outhist[ICMP6_ECHO_REPLY]++;
    577 			icmp6_reflect(n, noff);
    578 		}
    579 		break;
    580 
    581 	case ICMP6_ECHO_REPLY:
    582 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_echoreply);
    583 		if (code != 0)
    584 			goto badcode;
    585 		break;
    586 
    587 	case MLD6_LISTENER_QUERY:
    588 	case MLD6_LISTENER_REPORT:
    589 		if (icmp6len < sizeof(struct mld6_hdr))
    590 			goto badlen;
    591 		if (icmp6->icmp6_type == MLD6_LISTENER_QUERY) /* XXX: ugly... */
    592 			icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mldquery);
    593 		else
    594 			icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mldreport);
    595 		if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
    596 			/* give up local */
    597 			mld6_input(m, off);
    598 			m = NULL;
    599 			goto freeit;
    600 		}
    601 		mld6_input(n, off);
    602 		/* m stays. */
    603 		break;
    604 
    605 	case MLD6_LISTENER_DONE:
    606 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mlddone);
    607 		if (icmp6len < sizeof(struct mld6_hdr))	/* necessary? */
    608 			goto badlen;
    609 		break;		/* nothing to be done in kernel */
    610 
    611 	case MLD6_MTRACE_RESP:
    612 	case MLD6_MTRACE:
    613 		/* XXX: these two are experimental. not officially defind. */
    614 		/* XXX: per-interface statistics? */
    615 		break;		/* just pass it to applications */
    616 
    617 	case ICMP6_WRUREQUEST:	/* ICMP6_FQDN_QUERY */
    618 	    {
    619 		enum { WRU, FQDN } mode;
    620 
    621 		if (!icmp6_nodeinfo)
    622 			break;
    623 
    624 		if (icmp6len == sizeof(struct icmp6_hdr) + 4)
    625 			mode = WRU;
    626 		else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
    627 			mode = FQDN;
    628 		else
    629 			goto badlen;
    630 
    631 		if (mode == FQDN) {
    632 #ifndef PULLDOWN_TEST
    633 			IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_nodeinfo),
    634 					 IPPROTO_DONE);
    635 #endif
    636 			n = m_copy(m, 0, M_COPYALL);
    637 			if (n)
    638 				n = ni6_input(n, off);
    639 			/* XXX meaningless if n == NULL */
    640 			noff = sizeof(struct ip6_hdr);
    641 		} else {
    642 			u_char *p;
    643 			int maxlen, maxhlen;
    644 
    645 			if (code != 0)
    646 				goto badcode;
    647 			maxlen = sizeof(*nip6) + sizeof(*nicmp6) + 4;
    648 			if (maxlen >= MCLBYTES) {
    649 #ifdef DIAGNOSTIC
    650 				printf("MCLBYTES too small\n");
    651 #endif
    652 				/* Give up remote */
    653 				break;
    654 			}
    655 			MGETHDR(n, M_DONTWAIT, m->m_type);
    656 			if (n && maxlen > MHLEN) {
    657 				MCLGET(n, M_DONTWAIT);
    658 				if ((n->m_flags & M_EXT) == 0) {
    659 					m_free(n);
    660 					n = NULL;
    661 				}
    662 			}
    663 			if (n == NULL) {
    664 				/* Give up remote */
    665 				break;
    666 			}
    667 			n->m_len = 0;
    668 			maxhlen = M_TRAILINGSPACE(n) - maxlen;
    669 			if (maxhlen > hostnamelen)
    670 				maxhlen = hostnamelen;
    671 			/*
    672 			 * Copy IPv6 and ICMPv6 only.
    673 			 */
    674 			nip6 = mtod(n, struct ip6_hdr *);
    675 			bcopy(ip6, nip6, sizeof(struct ip6_hdr));
    676 			nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
    677 			bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
    678 			p = (u_char *)(nicmp6 + 1);
    679 			bzero(p, 4);
    680 			bcopy(hostname, p + 4, maxhlen); /*meaningless TTL*/
    681 			noff = sizeof(struct ip6_hdr);
    682 			M_COPY_PKTHDR(n, m); /* just for recvif */
    683 			n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
    684 				sizeof(struct icmp6_hdr) + 4 + maxhlen;
    685 			nicmp6->icmp6_type = ICMP6_WRUREPLY;
    686 			nicmp6->icmp6_code = 0;
    687 		}
    688 #undef hostnamelen
    689 		if (n) {
    690 			icmp6stat.icp6s_reflect++;
    691 			icmp6stat.icp6s_outhist[ICMP6_WRUREPLY]++;
    692 			icmp6_reflect(n, noff);
    693 		}
    694 		break;
    695 	    }
    696 
    697 	case ICMP6_WRUREPLY:
    698 		if (code != 0)
    699 			goto badcode;
    700 		break;
    701 
    702 	case ND_ROUTER_SOLICIT:
    703 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_routersolicit);
    704 		if (code != 0)
    705 			goto badcode;
    706 		if (icmp6len < sizeof(struct nd_router_solicit))
    707 			goto badlen;
    708 		if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
    709 			/* give up local */
    710 			nd6_rs_input(m, off, icmp6len);
    711 			m = NULL;
    712 			goto freeit;
    713 		}
    714 		nd6_rs_input(n, off, icmp6len);
    715 		/* m stays. */
    716 		break;
    717 
    718 	case ND_ROUTER_ADVERT:
    719 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_routeradvert);
    720 		if (code != 0)
    721 			goto badcode;
    722 		if (icmp6len < sizeof(struct nd_router_advert))
    723 			goto badlen;
    724 		if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
    725 			/* give up local */
    726 			nd6_ra_input(m, off, icmp6len);
    727 			m = NULL;
    728 			goto freeit;
    729 		}
    730 		nd6_ra_input(n, off, icmp6len);
    731 		/* m stays. */
    732 		break;
    733 
    734 	case ND_NEIGHBOR_SOLICIT:
    735 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_neighborsolicit);
    736 		if (code != 0)
    737 			goto badcode;
    738 		if (icmp6len < sizeof(struct nd_neighbor_solicit))
    739 			goto badlen;
    740 		if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
    741 			/* give up local */
    742 			nd6_ns_input(m, off, icmp6len);
    743 			m = NULL;
    744 			goto freeit;
    745 		}
    746 		nd6_ns_input(n, off, icmp6len);
    747 		/* m stays. */
    748 		break;
    749 
    750 	case ND_NEIGHBOR_ADVERT:
    751 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_neighboradvert);
    752 		if (code != 0)
    753 			goto badcode;
    754 		if (icmp6len < sizeof(struct nd_neighbor_advert))
    755 			goto badlen;
    756 		if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
    757 			/* give up local */
    758 			nd6_na_input(m, off, icmp6len);
    759 			m = NULL;
    760 			goto freeit;
    761 		}
    762 		nd6_na_input(n, off, icmp6len);
    763 		/* m stays. */
    764 		break;
    765 
    766 	case ND_REDIRECT:
    767 		icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_redirect);
    768 		if (code != 0)
    769 			goto badcode;
    770 		if (icmp6len < sizeof(struct nd_redirect))
    771 			goto badlen;
    772 		if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
    773 			/* give up local */
    774 			icmp6_redirect_input(m, off);
    775 			m = NULL;
    776 			goto freeit;
    777 		}
    778 		icmp6_redirect_input(n, off);
    779 		/* m stays. */
    780 		break;
    781 
    782 	case ICMP6_ROUTER_RENUMBERING:
    783 		if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
    784 		    code != ICMP6_ROUTER_RENUMBERING_RESULT)
    785 			goto badcode;
    786 		if (icmp6len < sizeof(struct icmp6_router_renum))
    787 			goto badlen;
    788 		break;
    789 
    790 	default:
    791 		printf("icmp6_input: unknown type %d(src=%s, dst=%s, ifid=%d)\n",
    792 		       icmp6->icmp6_type, ip6_sprintf(&ip6->ip6_src),
    793 		       ip6_sprintf(&ip6->ip6_dst),
    794 		       m->m_pkthdr.rcvif ? m->m_pkthdr.rcvif->if_index : 0);
    795 		if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
    796 			/* ICMPv6 error: MUST deliver it by spec... */
    797 			code = PRC_NCMDS;
    798 			/* deliver */
    799 		} else {
    800 			/* ICMPv6 informational: MUST not deliver */
    801 			break;
    802 		}
    803 	deliver:
    804 		if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
    805 			icmp6stat.icp6s_tooshort++;
    806 			goto freeit;
    807 		}
    808 #ifndef PULLDOWN_TEST
    809 		IP6_EXTHDR_CHECK(m, off,
    810 			sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr),
    811 			IPPROTO_DONE);
    812 		icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
    813 #else
    814 		IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off,
    815 			sizeof(*icmp6) + sizeof(struct ip6_hdr));
    816 		if (icmp6 == NULL) {
    817 			icmp6stat.icp6s_tooshort++;
    818 			return IPPROTO_DONE;
    819 		}
    820 #endif
    821 		bzero(&icmp6src, sizeof(icmp6src));
    822 		icmp6src.sin6_len = sizeof(struct sockaddr_in6);
    823 		icmp6src.sin6_family = AF_INET6;
    824 		icmp6src.sin6_addr = ((struct ip6_hdr *)(icmp6 + 1))->ip6_dst;
    825 
    826 		/* Detect the upper level protocol */
    827 	    {
    828 		void (*ctlfunc) __P((int, struct sockaddr *, void *));
    829 		struct ip6_hdr *eip6 = (struct ip6_hdr *)(icmp6 + 1);
    830 		u_int8_t nxt = eip6->ip6_nxt;
    831 		int eoff = off + sizeof(struct icmp6_hdr) +
    832 			sizeof(struct ip6_hdr);
    833 		struct ip6ctlparam ip6cp;
    834 		struct in6_addr *finaldst = NULL;
    835 		int icmp6type = icmp6->icmp6_type;
    836 		struct ip6_frag *fh;
    837 		struct ip6_rthdr *rth;
    838 		struct ip6_rthdr0 *rth0;
    839 		int rthlen;
    840 
    841 		while (1) { /* XXX: should avoid inf. loop explicitly? */
    842 			struct ip6_ext *eh;
    843 
    844 			switch(nxt) {
    845 			case IPPROTO_HOPOPTS:
    846 			case IPPROTO_DSTOPTS:
    847 			case IPPROTO_AH:
    848 #ifndef PULLDOWN_TEST
    849 				IP6_EXTHDR_CHECK(m, 0, eoff +
    850 						 sizeof(struct ip6_ext),
    851 						 IPPROTO_DONE);
    852 				eh = (struct ip6_ext *)(mtod(m, caddr_t)
    853 							+ eoff);
    854 #else
    855 				IP6_EXTHDR_GET(eh, struct ip6_ext *, m,
    856 					eoff, sizeof(*eh));
    857 				if (eh == NULL) {
    858 					icmp6stat.icp6s_tooshort++;
    859 					return IPPROTO_DONE;
    860 				}
    861 #endif
    862 
    863 				if (nxt == IPPROTO_AH)
    864 					eoff += (eh->ip6e_len + 2) << 2;
    865 				else
    866 					eoff += (eh->ip6e_len + 1) << 3;
    867 				nxt = eh->ip6e_nxt;
    868 				break;
    869 			case IPPROTO_ROUTING:
    870 				/*
    871 				 * When the erroneous packet contains a
    872 				 * routing header, we should examine the
    873 				 * header to determine the final destination.
    874 				 * Otherwise, we can't properly update
    875 				 * information that depends on the final
    876 				 * destination (e.g. path MTU).
    877 				 */
    878 #ifndef PULLDOWN_TEST
    879 				IP6_EXTHDR_CHECK(m, 0, eoff + sizeof(*rth),
    880 						 IPPROTO_DONE);
    881 				rth = (struct ip6_rthdr *)(mtod(m, caddr_t)
    882 							   + eoff);
    883 #else
    884 				IP6_EXTHDR_GET(rth, struct ip6_rthdr *, m,
    885 					eoff, sizeof(*rth));
    886 				if (rth == NULL) {
    887 					icmp6stat.icp6s_tooshort++;
    888 					return IPPROTO_DONE;
    889 				}
    890 #endif
    891 				rthlen = (rth->ip6r_len + 1) << 3;
    892 				/*
    893 				 * XXX: currently there is no
    894 				 * officially defined type other
    895 				 * than type-0.
    896 				 * Note that if the segment left field
    897 				 * is 0, all intermediate hops must
    898 				 * have been passed.
    899 				 */
    900 				if (rth->ip6r_segleft &&
    901 				    rth->ip6r_type == IPV6_RTHDR_TYPE_0) {
    902 					int hops;
    903 
    904 #ifndef PULLDOWN_TEST
    905 					IP6_EXTHDR_CHECK(m, 0, eoff + rthlen,
    906 							 IPPROTO_DONE);
    907 					rth0 = (struct ip6_rthdr0 *)(mtod(m, caddr_t) + eoff);
    908 #else
    909 					IP6_EXTHDR_GET(rth0,
    910 						       struct ip6_rthdr0 *, m,
    911 						       eoff, rthlen);
    912 					if (rth0 == NULL) {
    913 						icmp6stat.icp6s_tooshort++;
    914 						return IPPROTO_DONE;
    915 					}
    916 #endif
    917 					/* just ignore a bogus header */
    918 					if ((rth0->ip6r0_len % 2) == 0 &&
    919 					    (hops = rth0->ip6r0_len/2))
    920 						finaldst = (struct in6_addr *)(rth0 + 1) + (hops - 1);
    921 				}
    922 				eoff += rthlen;
    923 				nxt = rth->ip6r_nxt;
    924 				break;
    925 			case IPPROTO_FRAGMENT:
    926 #ifndef PULLDOWN_TEST
    927 				IP6_EXTHDR_CHECK(m, 0, eoff +
    928 						 sizeof(struct ip6_frag),
    929 						 IPPROTO_DONE);
    930 				fh = (struct ip6_frag *)(mtod(m, caddr_t)
    931 							 + eoff);
    932 #else
    933 				IP6_EXTHDR_GET(fh, struct ip6_frag *, m,
    934 					eoff, sizeof(*fh));
    935 				if (fh == NULL) {
    936 					icmp6stat.icp6s_tooshort++;
    937 					return IPPROTO_DONE;
    938 				}
    939 #endif
    940 				/*
    941 				 * Data after a fragment header is meaningless
    942 				 * unless it is the first fragment, but
    943 				 * we'll go to the notify label for path MTU
    944 				 * discovery.
    945 				 */
    946 				if (fh->ip6f_offlg & IP6F_OFF_MASK)
    947 					goto notify;
    948 
    949 				eoff += sizeof(struct ip6_frag);
    950 				nxt = fh->ip6f_nxt;
    951 				break;
    952 			default:
    953 				/*
    954 				 * This case includes ESP and the No Next
    955 				 * Header. In such cases going to the notify
    956 				 * label does not have any meaning
    957 				 * (i.e. ctlfunc will be NULL), but we go
    958 				 * anyway since we might have to update
    959 				 * path MTU information.
    960 				 */
    961 				goto notify;
    962 			}
    963 		}
    964 	    notify:
    965 #ifndef PULLDOWN_TEST
    966 		icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
    967 #else
    968 		IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off,
    969 			sizeof(*icmp6) + sizeof(struct ip6_hdr));
    970 		if (icmp6 == NULL) {
    971 			icmp6stat.icp6s_tooshort++;
    972 			return IPPROTO_DONE;
    973 		}
    974 #endif
    975 		if (icmp6type == ICMP6_PACKET_TOO_BIG) {
    976 			if (finaldst == NULL)
    977 				finaldst = &((struct ip6_hdr *)(icmp6 + 1))->ip6_dst;
    978 			icmp6_mtudisc_update(finaldst, icmp6, m);
    979 		}
    980 
    981 		ctlfunc = (void (*) __P((int, struct sockaddr *, void *)))
    982 			(inet6sw[ip6_protox[nxt]].pr_ctlinput);
    983 		if (ctlfunc) {
    984 			ip6cp.ip6c_m = m;
    985 			ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
    986 			ip6cp.ip6c_off = eoff;
    987 			(*ctlfunc)(code, (struct sockaddr *)&icmp6src, &ip6cp);
    988 		}
    989 	    }
    990 		break;
    991 
    992 	badcode:
    993 		icmp6stat.icp6s_badcode++;
    994 		break;
    995 
    996 	badlen:
    997 		icmp6stat.icp6s_badlen++;
    998 		break;
    999 	}
   1000 
   1001 	icmp6_rip6_input(&m, *offp);
   1002 	return IPPROTO_DONE;
   1003 
   1004  freeit:
   1005 	m_freem(m);
   1006 	return IPPROTO_DONE;
   1007 }
   1008 
   1009 static void
   1010 icmp6_mtudisc_update(dst, icmp6, m)
   1011 	struct in6_addr *dst;
   1012 	struct icmp6_hdr *icmp6;/* we can assume the validity of the pointer */
   1013 	struct mbuf *m;	/* currently unused but added for scoped addrs */
   1014 {
   1015 	u_int mtu = ntohl(icmp6->icmp6_mtu);
   1016 	struct rtentry *rt = NULL;
   1017 	struct sockaddr_in6 sin6;
   1018 
   1019 	bzero(&sin6, sizeof(sin6));
   1020 	sin6.sin6_family = PF_INET6;
   1021 	sin6.sin6_len = sizeof(struct sockaddr_in6);
   1022 	sin6.sin6_addr = *dst;
   1023 	/* sin6.sin6_scope_id = XXX: should be set if DST is a scoped addr */
   1024 	rt = rtalloc1((struct sockaddr *)&sin6, 1);	/*clone*/
   1025 	if (!rt || (rt->rt_flags & RTF_HOST) == 0) {
   1026 		if (rt)
   1027 			RTFREE(rt);
   1028 		rt = icmp6_mtudisc_clone((struct sockaddr *)&sin6);
   1029 	}
   1030 
   1031 	if (rt && (rt->rt_flags & RTF_HOST)
   1032 	    && !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
   1033 		if (mtu < IPV6_MMTU) {
   1034 				/* xxx */
   1035 			rt->rt_rmx.rmx_locks |= RTV_MTU;
   1036 		} else if (mtu < rt->rt_ifp->if_mtu &&
   1037 			   rt->rt_rmx.rmx_mtu > mtu) {
   1038 			rt->rt_rmx.rmx_mtu = mtu;
   1039 		}
   1040 	}
   1041 	if (rt)
   1042 		RTFREE(rt);
   1043 }
   1044 
   1045 /*
   1046  * Process a Node Information Query packet, (roughly) based on
   1047  * draft-ietf-ipngwg-icmp-name-lookups-05.
   1048  *
   1049  * Spec incompatibilities:
   1050  * - IPv6 Subject address handling
   1051  * - IPv4 Subject address handling support missing
   1052  * - Proxy reply (answer even if it's not for me)
   1053  * - "Supported Qtypes" support missing
   1054  * - joins NI group address at in6_ifattach() time only, does not cope
   1055  *   with hostname changes by sethostname(3)
   1056  */
   1057 #ifndef offsetof		/* XXX */
   1058 #define	offsetof(type, member)	((size_t)(&((type *)0)->member))
   1059 #endif
   1060 static struct mbuf *
   1061 ni6_input(m, off)
   1062 	struct mbuf *m;
   1063 	int off;
   1064 {
   1065 	struct icmp6_nodeinfo *ni6, *nni6;
   1066 	struct mbuf *n = NULL;
   1067 	u_int16_t qtype;
   1068 	int subjlen;
   1069 	int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
   1070 	struct ni_reply_fqdn *fqdn;
   1071 	int addrs;		/* for NI_QTYPE_NODEADDR */
   1072 	struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
   1073 	struct sockaddr_in6 sin6;
   1074 	struct ip6_hdr *ip6;
   1075 	int oldfqdn = 0;	/* if 1, return pascal string (03 draft) */
   1076 	char *subj;
   1077 
   1078 	ip6 = mtod(m, struct ip6_hdr *);
   1079 #ifndef PULLDOWN_TEST
   1080 	ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
   1081 #else
   1082 	IP6_EXTHDR_GET(ni6, struct icmp6_nodeinfo *, m, off, sizeof(*ni6));
   1083 	if (ni6 == NULL) {
   1084 		/* m is already reclaimed */
   1085 		return NULL;
   1086 	}
   1087 #endif
   1088 
   1089 	/*
   1090 	 * Validate IPv6 destination address.
   1091 	 *
   1092 	 * We accept packets with the following IPv6 destination address:
   1093 	 * - Responder's unicast/anycast address,
   1094 	 * - link-local multicast address
   1095 	 * This is a violation to last paragraph in icmp-name-lookups-05
   1096 	 * page 4, which restricts IPv6 destination address of a query to:
   1097 	 * - Responder's unicast/anycast address,
   1098 	 * - NI group address for a name belongs to the Responder, or
   1099 	 * - NI group address for a name for which the Responder is providing
   1100 	 *   proxy service.
   1101 	 * (note: NI group address is a link-local multicast address)
   1102 	 *
   1103 	 * We allow any link-local multicast address, since "ping6 -w ff02::1"
   1104 	 * has been really useful for us debugging our network.  Also this is
   1105 	 * still questionable if the restriction in spec buy us security at all,
   1106 	 * since RFC2463 permits echo packet to multicast destination.
   1107 	 * Even if we forbid NI query to ff02::1, we can effectively get the
   1108 	 * same result as "ping6 -w ff02::1" by the following steps:
   1109 	 * - run "ping6 ff02::1", then
   1110 	 * - run "ping6 -w" for all addresses replied.
   1111 	 */
   1112 	bzero(&sin6, sizeof(sin6));
   1113 	sin6.sin6_family = AF_INET6;
   1114 	sin6.sin6_len = sizeof(struct sockaddr_in6);
   1115 	bcopy(&ip6->ip6_dst, &sin6.sin6_addr, sizeof(sin6.sin6_addr));
   1116 	/* XXX scopeid */
   1117 	if (ifa_ifwithaddr((struct sockaddr *)&sin6))
   1118 		; /*unicast/anycast, fine*/
   1119 	else if (IN6_IS_ADDR_MC_LINKLOCAL(&sin6.sin6_addr))
   1120 		; /*violates spec slightly, see above*/
   1121 	else
   1122 		goto bad;
   1123 
   1124 	/* guess reply length */
   1125 	qtype = ntohs(ni6->ni_qtype);
   1126 	switch (qtype) {
   1127 	case NI_QTYPE_NOOP:
   1128 		break;		/* no reply data */
   1129 	case NI_QTYPE_SUPTYPES:
   1130 		goto bad;	/* xxx: to be implemented */
   1131 		break;
   1132 	case NI_QTYPE_FQDN:
   1133 		/* XXX will append a mbuf */
   1134 		replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
   1135 		break;
   1136 	case NI_QTYPE_NODEADDR:
   1137 		addrs = ni6_addrs(ni6, m, &ifp);
   1138 		if ((replylen += addrs * sizeof(struct in6_addr)) > MCLBYTES)
   1139 			replylen = MCLBYTES; /* XXX: we'll truncate later */
   1140 		break;
   1141 	default:
   1142 		/*
   1143 		 * XXX: We must return a reply with the ICMP6 code
   1144 		 * `unknown Qtype' in this case. However we regard the case
   1145 		 * as an FQDN query for backward compatibility.
   1146 		 * Older versions set a random value to this field,
   1147 		 * so it rarely varies in the defined qtypes.
   1148 		 * But the mechanism is not reliable...
   1149 		 * maybe we should obsolete older versions.
   1150 		 */
   1151 		qtype = NI_QTYPE_FQDN;
   1152 		/* XXX will append a mbuf */
   1153 		replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
   1154 		oldfqdn++;
   1155 		break;
   1156 	}
   1157 
   1158 	/* validate query Subject field. */
   1159 	subjlen = m->m_pkthdr.len - off - sizeof(struct icmp6_nodeinfo);
   1160 	switch (qtype) {
   1161 	case NI_QTYPE_NOOP:
   1162 	case NI_QTYPE_SUPTYPES:
   1163 		if (subjlen != 0)
   1164 			goto bad;
   1165 		break;
   1166 
   1167 	case NI_QTYPE_FQDN:
   1168 	case NI_QTYPE_NODEADDR:
   1169 		switch (ni6->ni_code) {
   1170 		case ICMP6_NI_SUBJ_IPV6:
   1171 #if ICMP6_NI_SUBJ_IPV6 != 0
   1172 		case 0:
   1173 #endif
   1174 			/*
   1175 			 * backward compatibility - try to accept 03 draft
   1176 			 * format, where no Subject is present.
   1177 			 */
   1178 			if (subjlen == 0) {
   1179 				oldfqdn++;
   1180 				break;
   1181 			}
   1182 
   1183 			if (subjlen != sizeof(sin6.sin6_addr))
   1184 				goto bad;
   1185 
   1186 			/*
   1187 			 * Validate Subject address.
   1188 			 *
   1189 			 * Not sure what exactly does "address belongs to the
   1190 			 * node" mean in the spec, is it just unicast, or what?
   1191 			 *
   1192 			 * At this moment we consider Subject address as
   1193 			 * "belong to the node" if the Subject address equals
   1194 			 * to the IPv6 destination address; validation for
   1195 			 * IPv6 destination address should have done enough
   1196 			 * check for us.
   1197 			 *
   1198 			 * We do not do proxy at this moment.
   1199 			 */
   1200 			/* m_pulldown instead of copy? */
   1201 			m_copydata(m, off + sizeof(struct icmp6_nodeinfo),
   1202 			    subjlen, (caddr_t)&sin6.sin6_addr);
   1203 			/* XXX kame scope hack */
   1204 			if (IN6_IS_SCOPE_LINKLOCAL(&sin6.sin6_addr)) {
   1205 #ifdef FAKE_LOOPBACK_IF
   1206 				if ((m->m_flags & M_PKTHDR) != 0 &&
   1207 				    m->m_pkthdr.rcvif) {
   1208 					sin6.sin6_addr.s6_addr16[1] =
   1209 					    htons(m->m_pkthdr.rcvif->if_index);
   1210 				}
   1211 #else
   1212 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
   1213 					sin6.sin6_addr.s6_addr16[1] =
   1214 					    ip6->ip6_dst.s6_addr16[1];
   1215 				}
   1216 #endif
   1217 			}
   1218 			if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &sin6.sin6_addr))
   1219 				break;
   1220 			/*
   1221 			 * XXX if we are to allow other cases, we should really
   1222 			 * be careful about scope here.
   1223 			 * basically, we should disallow queries toward IPv6
   1224 			 * destination X with subject Y, if scope(X) > scope(Y).
   1225 			 * if we allow scope(X) > scope(Y), it will result in
   1226 			 * information leakage across scope boundary.
   1227 			 */
   1228 			goto bad;
   1229 
   1230 		case ICMP6_NI_SUBJ_FQDN:
   1231 			/*
   1232 			 * Validate Subject name with gethostname(3).
   1233 			 *
   1234 			 * The behavior may need some debate, since:
   1235 			 * - we are not sure if the node has FQDN as
   1236 			 *   hostname (returned by gethostname(3)).
   1237 			 * - the code does wildcard match for truncated names.
   1238 			 *   however, we are not sure if we want to perform
   1239 			 *   wildcard match, if gethostname(3) side has
   1240 			 *   truncated hostname.
   1241 			 */
   1242 			n = ni6_nametodns(hostname, hostnamelen, 0);
   1243 			if (!n || n->m_next || n->m_len == 0)
   1244 				goto bad;
   1245 			IP6_EXTHDR_GET(subj, char *, m,
   1246 			    off + sizeof(struct icmp6_nodeinfo), subjlen);
   1247 			if (subj == NULL)
   1248 				goto bad;
   1249 			if (!ni6_dnsmatch(subj, subjlen, mtod(n, const char *),
   1250 					n->m_len)) {
   1251 				goto bad;
   1252 			}
   1253 			m_freem(n);
   1254 			n = NULL;
   1255 			break;
   1256 
   1257 		case ICMP6_NI_SUBJ_IPV4:	/* xxx: to be implemented? */
   1258 		default:
   1259 			goto bad;
   1260 		}
   1261 		break;
   1262 
   1263 	default:
   1264 		/* should never be here due to "switch (qtype)" above */
   1265 		goto bad;
   1266 	}
   1267 
   1268 	/* allocate a mbuf to reply. */
   1269 	MGETHDR(n, M_DONTWAIT, m->m_type);
   1270 	if (n == NULL) {
   1271 		m_freem(m);
   1272 		return(NULL);
   1273 	}
   1274 	M_COPY_PKTHDR(n, m); /* just for recvif */
   1275 	if (replylen > MHLEN) {
   1276 		if (replylen > MCLBYTES) {
   1277 			 /*
   1278 			  * XXX: should we try to allocate more? But MCLBYTES is
   1279 			  * probably much larger than IPV6_MMTU...
   1280 			  */
   1281 			goto bad;
   1282 		}
   1283 		MCLGET(n, M_DONTWAIT);
   1284 		if ((n->m_flags & M_EXT) == 0) {
   1285 			goto bad;
   1286 		}
   1287 	}
   1288 	n->m_pkthdr.len = n->m_len = replylen;
   1289 
   1290 	/* copy mbuf header and IPv6 + Node Information base headers */
   1291 	bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
   1292 	nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
   1293 	bcopy((caddr_t)ni6, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));
   1294 
   1295 	/* qtype dependent procedure */
   1296 	switch (qtype) {
   1297 	case NI_QTYPE_NOOP:
   1298 		nni6->ni_flags = 0;
   1299 		break;
   1300 	case NI_QTYPE_SUPTYPES:
   1301 		goto bad;	/* xxx: to be implemented */
   1302 		break;
   1303 	case NI_QTYPE_FQDN:
   1304 		fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
   1305 						sizeof(struct ip6_hdr) +
   1306 						sizeof(struct icmp6_nodeinfo));
   1307 		nni6->ni_flags = 0; /* XXX: meaningless TTL */
   1308 		fqdn->ni_fqdn_ttl = 0;	/* ditto. */
   1309 		/*
   1310 		 * XXX do we really have FQDN in variable "hostname"?
   1311 		 */
   1312 		n->m_next = ni6_nametodns(hostname, hostnamelen, oldfqdn);
   1313 		if (n->m_next == NULL)
   1314 			goto bad;
   1315 		/* XXX we assume that n->m_next is not a chain */
   1316 		if (n->m_next->m_next != NULL)
   1317 			goto bad;
   1318 		n->m_pkthdr.len += n->m_next->m_len;
   1319 		break;
   1320 	case NI_QTYPE_NODEADDR:
   1321 	{
   1322 		int lenlim, copied;
   1323 
   1324 		if (n->m_flags & M_EXT)
   1325 			lenlim = MCLBYTES - sizeof(struct ip6_hdr) -
   1326 				sizeof(struct icmp6_nodeinfo);
   1327 		else
   1328 			lenlim = MHLEN - sizeof(struct ip6_hdr) -
   1329 				sizeof(struct icmp6_nodeinfo);
   1330 		copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
   1331 		/* XXX: reset mbuf length */
   1332 		n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
   1333 			sizeof(struct icmp6_nodeinfo) + copied;
   1334 		break;
   1335 	}
   1336 	default:
   1337 		break;		/* XXX impossible! */
   1338 	}
   1339 
   1340 	nni6->ni_type = ICMP6_NI_REPLY;
   1341 	nni6->ni_code = ICMP6_NI_SUCESS;
   1342 	m_freem(m);
   1343 	return(n);
   1344 
   1345   bad:
   1346 	m_freem(m);
   1347 	if (n)
   1348 		m_freem(n);
   1349 	return(NULL);
   1350 }
   1351 #undef hostnamelen
   1352 
   1353 /*
   1354  * make a mbuf with DNS-encoded string.  no compression support.
   1355  *
   1356  * XXX names with less than 2 dots (like "foo" or "foo.section") will be
   1357  * treated as truncated name (two \0 at the end).  this is a wild guess.
   1358  */
   1359 static struct mbuf *
   1360 ni6_nametodns(name, namelen, old)
   1361 	const char *name;
   1362 	int namelen;
   1363 	int old;	/* return pascal string if non-zero */
   1364 {
   1365 	struct mbuf *m;
   1366 	char *cp, *ep;
   1367 	const char *p, *q;
   1368 	int i, len, nterm;
   1369 
   1370 	if (old)
   1371 		len = namelen + 1;
   1372 	else
   1373 		len = MCLBYTES;
   1374 
   1375 	/* because MAXHOSTNAMELEN is usually 256, we use cluster mbuf */
   1376 	MGET(m, M_DONTWAIT, MT_DATA);
   1377 	if (m && len > MLEN) {
   1378 		MCLGET(m, M_DONTWAIT);
   1379 		if ((m->m_flags & M_EXT) == 0)
   1380 			goto fail;
   1381 	}
   1382 	if (!m)
   1383 		goto fail;
   1384 	m->m_next = NULL;
   1385 
   1386 	if (old) {
   1387 		m->m_len = len;
   1388 		*mtod(m, char *) = namelen;
   1389 		bcopy(name, mtod(m, char *) + 1, namelen);
   1390 		return m;
   1391 	} else {
   1392 		m->m_len = 0;
   1393 		cp = mtod(m, char *);
   1394 		ep = mtod(m, char *) + M_TRAILINGSPACE(m);
   1395 
   1396 		/* if not certain about my name, return empty buffer */
   1397 		if (namelen == 0)
   1398 			return m;
   1399 
   1400 		/*
   1401 		 * guess if it looks like shortened hostname, or FQDN.
   1402 		 * shortened hostname needs two trailing "\0".
   1403 		 */
   1404 		i = 0;
   1405 		for (p = name; p < name + namelen; p++) {
   1406 			if (*p && *p == '.')
   1407 				i++;
   1408 		}
   1409 		if (i < 2)
   1410 			nterm = 2;
   1411 		else
   1412 			nterm = 1;
   1413 
   1414 		p = name;
   1415 		while (cp < ep && p < name + namelen) {
   1416 			i = 0;
   1417 			for (q = p; q < name + namelen && *q && *q != '.'; q++)
   1418 				i++;
   1419 			/* result does not fit into mbuf */
   1420 			if (cp + i + 1 >= ep)
   1421 				goto fail;
   1422 			/* DNS label length restriction, RFC1035 page 8 */
   1423 			if (i >= 64)
   1424 				goto fail;
   1425 			*cp++ = i;
   1426 			bcopy(p, cp, i);
   1427 			cp += i;
   1428 			p = q;
   1429 			if (p < name + namelen && *p == '.')
   1430 				p++;
   1431 		}
   1432 		/* termination */
   1433 		if (cp + nterm >= ep)
   1434 			goto fail;
   1435 		while (nterm-- > 0)
   1436 			*cp++ = '\0';
   1437 		m->m_len = cp - mtod(m, char *);
   1438 		return m;
   1439 	}
   1440 
   1441 	panic("should not reach here");
   1442 	/*NOTREACHED*/
   1443 
   1444  fail:
   1445 	if (m)
   1446 		m_freem(m);
   1447 	return NULL;
   1448 }
   1449 
   1450 /*
   1451  * check if two DNS-encoded string matches.  takes care of truncated
   1452  * form (with \0\0 at the end).  no compression support.
   1453  */
   1454 static int
   1455 ni6_dnsmatch(a, alen, b, blen)
   1456 	const char *a;
   1457 	int alen;
   1458 	const char *b;
   1459 	int blen;
   1460 {
   1461 	const char *a0, *b0;
   1462 	int l;
   1463 
   1464 	/* simplest case - need validation? */
   1465 	if (alen == blen && bcmp(a, b, alen) == 0)
   1466 		return 1;
   1467 
   1468 	a0 = a;
   1469 	b0 = b;
   1470 
   1471 	/* termination is mandatory */
   1472 	if (alen < 2 || blen < 2)
   1473 		return 0;
   1474 	if (a0[alen - 1] != '\0' || b0[blen - 1] != '\0')
   1475 		return 0;
   1476 	alen--;
   1477 	blen--;
   1478 
   1479 	while (a - a0 < alen && b - b0 < blen) {
   1480 		if (a - a0 + 1 > alen || b - b0 + 1 > blen)
   1481 			return 0;
   1482 
   1483 		if ((signed char)a[0] < 0 || (signed char)b[0] < 0)
   1484 			return 0;
   1485 		/* we don't support compression yet */
   1486 		if (a[0] >= 64 || b[0] >= 64)
   1487 			return 0;
   1488 
   1489 		/* truncated case */
   1490 		if (a[0] == 0 && a - a0 == alen - 1)
   1491 			return 1;
   1492 		if (b[0] == 0 && b - b0 == blen - 1)
   1493 			return 1;
   1494 		if (a[0] == 0 || b[0] == 0)
   1495 			return 0;
   1496 
   1497 		if (a[0] != b[0])
   1498 			return 0;
   1499 		l = a[0];
   1500 		if (a - a0 + 1 + l > alen || b - b0 + 1 + l > blen)
   1501 			return 0;
   1502 		if (bcmp(a + 1, b + 1, l) != 0)
   1503 			return 0;
   1504 
   1505 		a += 1 + l;
   1506 		b += 1 + l;
   1507 	}
   1508 
   1509 	if (a - a0 == alen && b - b0 == blen)
   1510 		return 1;
   1511 	else
   1512 		return 0;
   1513 }
   1514 
   1515 /*
   1516  * calculate the number of addresses to be returned in the node info reply.
   1517  */
   1518 static int
   1519 ni6_addrs(ni6, m, ifpp)
   1520 	struct icmp6_nodeinfo *ni6;
   1521 	struct mbuf *m;
   1522 	struct ifnet **ifpp;
   1523 {
   1524 	register struct ifnet *ifp;
   1525 	register struct in6_ifaddr *ifa6;
   1526 	register struct ifaddr *ifa;
   1527 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
   1528 	int addrs = 0, addrsofif, iffound = 0;
   1529 
   1530 	for (ifp = TAILQ_FIRST(&ifnet); ifp; ifp = TAILQ_NEXT(ifp, if_list))
   1531 	{
   1532 		addrsofif = 0;
   1533 		for (ifa = ifp->if_addrlist.tqh_first; ifa;
   1534 		     ifa = ifa->ifa_list.tqe_next)
   1535 		{
   1536 			if (ifa->ifa_addr->sa_family != AF_INET6)
   1537 				continue;
   1538 			ifa6 = (struct in6_ifaddr *)ifa;
   1539 
   1540 			if (!(ni6->ni_flags & NI_NODEADDR_FLAG_ALL) &&
   1541 			    IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
   1542 					       &ifa6->ia_addr.sin6_addr))
   1543 				iffound = 1;
   1544 
   1545 			/*
   1546 			 * IPv4-mapped addresses can only be returned by a
   1547 			 * Node Information proxy, since they represent
   1548 			 * addresses of IPv4-only nodes, which perforce do
   1549 			 * not implement this protocol.
   1550 			 * [icmp-name-lookups-05]
   1551 			 * So we don't support NI_NODEADDR_FLAG_COMPAT in
   1552 			 * this function at this moment.
   1553 			 */
   1554 
   1555 			if (ifa6->ia6_flags & IN6_IFF_ANYCAST)
   1556 				continue; /* we need only unicast addresses */
   1557 
   1558 			if ((ni6->ni_flags & (NI_NODEADDR_FLAG_LINKLOCAL |
   1559 					      NI_NODEADDR_FLAG_SITELOCAL |
   1560 					      NI_NODEADDR_FLAG_GLOBAL)) == 0)
   1561 				continue;
   1562 
   1563 			/* What do we have to do about ::1? */
   1564 			switch(in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
   1565 			 case IPV6_ADDR_SCOPE_LINKLOCAL:
   1566 				if (ni6->ni_flags & NI_NODEADDR_FLAG_LINKLOCAL)
   1567 					addrsofif++;
   1568 				break;
   1569 			 case IPV6_ADDR_SCOPE_SITELOCAL:
   1570 				if (ni6->ni_flags & NI_NODEADDR_FLAG_SITELOCAL)
   1571 					addrsofif++;
   1572 				break;
   1573 			 case IPV6_ADDR_SCOPE_GLOBAL:
   1574 				 if (ni6->ni_flags & NI_NODEADDR_FLAG_GLOBAL)
   1575 					 addrsofif++;
   1576 				 break;
   1577 			 default:
   1578 				 continue;
   1579 			}
   1580 		}
   1581 		if (iffound) {
   1582 			*ifpp = ifp;
   1583 			return(addrsofif);
   1584 		}
   1585 
   1586 		addrs += addrsofif;
   1587 	}
   1588 
   1589 	return(addrs);
   1590 }
   1591 
   1592 static int
   1593 ni6_store_addrs(ni6, nni6, ifp0, resid)
   1594 	struct icmp6_nodeinfo *ni6, *nni6;
   1595 	struct ifnet *ifp0;
   1596 	int resid;
   1597 {
   1598 	register struct ifnet *ifp = ifp0 ? ifp0 : TAILQ_FIRST(&ifnet);
   1599 	register struct in6_ifaddr *ifa6;
   1600 	register struct ifaddr *ifa;
   1601 	int docopy, copied = 0;
   1602 	u_char *cp = (u_char *)(nni6 + 1);
   1603 
   1604 	if (ifp0 == NULL && !(ni6->ni_flags & NI_NODEADDR_FLAG_ALL))
   1605 		return(0);	/* needless to copy */
   1606 
   1607 	for (; ifp; ifp = TAILQ_NEXT(ifp, if_list))
   1608 	{
   1609 		for (ifa = ifp->if_addrlist.tqh_first; ifa;
   1610 		     ifa = ifa->ifa_list.tqe_next)
   1611 		{
   1612 			docopy = 0;
   1613 
   1614 			if (ifa->ifa_addr->sa_family != AF_INET6)
   1615 				continue;
   1616 			ifa6 = (struct in6_ifaddr *)ifa;
   1617 
   1618 			if (ifa6->ia6_flags & IN6_IFF_ANYCAST) {
   1619 				/* just experimental. not in the spec. */
   1620 				if (ni6->ni_flags & NI_NODEADDR_FLAG_ANYCAST)
   1621 					docopy = 1;
   1622 				else
   1623 					continue;
   1624 			}
   1625 			else {	/* unicast address */
   1626 				if (ni6->ni_flags & NI_NODEADDR_FLAG_ANYCAST)
   1627 					continue;
   1628 				else
   1629 					docopy = 1;
   1630 			}
   1631 
   1632 			/* What do we have to do about ::1? */
   1633 			switch(in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
   1634 			 case IPV6_ADDR_SCOPE_LINKLOCAL:
   1635 				if (ni6->ni_flags & NI_NODEADDR_FLAG_LINKLOCAL)
   1636 					docopy = 1;
   1637 				break;
   1638 			 case IPV6_ADDR_SCOPE_SITELOCAL:
   1639 				if (ni6->ni_flags & NI_NODEADDR_FLAG_SITELOCAL)
   1640 					docopy = 1;
   1641 				break;
   1642 			 case IPV6_ADDR_SCOPE_GLOBAL:
   1643 				 if (ni6->ni_flags & NI_NODEADDR_FLAG_GLOBAL)
   1644 					 docopy = 1;
   1645 				 break;
   1646 			 default:
   1647 				 continue;
   1648 			}
   1649 
   1650 			if (docopy) {
   1651 				if (resid < sizeof(struct in6_addr)) {
   1652 					/*
   1653 					 * We give up much more copy.
   1654 					 * Set the truncate flag and return.
   1655 					 */
   1656 					nni6->ni_flags |=
   1657 						NI_NODEADDR_FLAG_TRUNCATE;
   1658 					return(copied);
   1659 				}
   1660 				bcopy(&ifa6->ia_addr.sin6_addr, cp,
   1661 				      sizeof(struct in6_addr));
   1662 				/* XXX: KAME link-local hack; remove ifindex */
   1663 				if (IN6_IS_ADDR_LINKLOCAL(&ifa6->ia_addr.sin6_addr))
   1664 					((struct in6_addr *)cp)->s6_addr16[1] = 0;
   1665 				cp += sizeof(struct in6_addr);
   1666 				resid -= sizeof(struct in6_addr);
   1667 				copied += sizeof(struct in6_addr);
   1668 			}
   1669 		}
   1670 		if (ifp0)	/* we need search only on the specified IF */
   1671 			break;
   1672 	}
   1673 
   1674 	return(copied);
   1675 }
   1676 
   1677 /*
   1678  * XXX almost dup'ed code with rip6_input.
   1679  */
   1680 static int
   1681 icmp6_rip6_input(mp, off)
   1682 	struct	mbuf **mp;
   1683 	int	off;
   1684 {
   1685 	struct mbuf *m = *mp;
   1686 	register struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
   1687 	register struct in6pcb *in6p;
   1688 	struct in6pcb *last = NULL;
   1689 	struct sockaddr_in6 rip6src;
   1690 	struct icmp6_hdr *icmp6;
   1691 	struct mbuf *opts = NULL;
   1692 
   1693 #ifndef PULLDOWN_TEST
   1694 	/* this is assumed to be safe. */
   1695 	icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
   1696 #else
   1697 	IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
   1698 	if (icmp6 == NULL) {
   1699 		/* m is already reclaimed */
   1700 		return IPPROTO_DONE;
   1701 	}
   1702 #endif
   1703 
   1704 	bzero(&rip6src, sizeof(rip6src));
   1705 	rip6src.sin6_len = sizeof(struct sockaddr_in6);
   1706 	rip6src.sin6_family = AF_INET6;
   1707 	rip6src.sin6_addr = ip6->ip6_src;
   1708 	if (IN6_IS_SCOPE_LINKLOCAL(&rip6src.sin6_addr))
   1709 		rip6src.sin6_addr.s6_addr16[1] = 0;
   1710 	if (m->m_pkthdr.rcvif) {
   1711 		if (IN6_IS_SCOPE_LINKLOCAL(&rip6src.sin6_addr))
   1712 			rip6src.sin6_scope_id = m->m_pkthdr.rcvif->if_index;
   1713 		else
   1714 			rip6src.sin6_scope_id = 0;
   1715 	} else
   1716 		rip6src.sin6_scope_id = 0;
   1717 
   1718 	for (in6p = rawin6pcb.in6p_next;
   1719 	     in6p != &rawin6pcb; in6p = in6p->in6p_next)
   1720 	{
   1721 		if (in6p->in6p_ip6_nxt != IPPROTO_ICMPV6)
   1722 			continue;
   1723 		if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr) &&
   1724 		   !IN6_ARE_ADDR_EQUAL(&in6p->in6p_laddr, &ip6->ip6_dst))
   1725 			continue;
   1726 		if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr) &&
   1727 		   !IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr, &ip6->ip6_src))
   1728 			continue;
   1729 		if (in6p->in6p_icmp6filt
   1730 		    && ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
   1731 				 in6p->in6p_icmp6filt))
   1732 			continue;
   1733 		if (last) {
   1734 			struct	mbuf *n;
   1735 			if ((n = m_copy(m, 0, (int)M_COPYALL)) != NULL) {
   1736 				if (last->in6p_flags & IN6P_CONTROLOPTS)
   1737 					ip6_savecontrol(last, &opts, ip6, n);
   1738 				/* strip intermediate headers */
   1739 				m_adj(n, off);
   1740 				if (sbappendaddr(&last->in6p_socket->so_rcv,
   1741 						 (struct sockaddr *)&rip6src,
   1742 						 n, opts) == 0) {
   1743 					/* should notify about lost packet */
   1744 					m_freem(n);
   1745 					if (opts)
   1746 						m_freem(opts);
   1747 				} else
   1748 					sorwakeup(last->in6p_socket);
   1749 				opts = NULL;
   1750 			}
   1751 		}
   1752 		last = in6p;
   1753 	}
   1754 	if (last) {
   1755 		if (last->in6p_flags & IN6P_CONTROLOPTS)
   1756 			ip6_savecontrol(last, &opts, ip6, m);
   1757 		/* strip intermediate headers */
   1758 		m_adj(m, off);
   1759 		if (sbappendaddr(&last->in6p_socket->so_rcv,
   1760 				(struct sockaddr *)&rip6src, m, opts) == 0) {
   1761 			m_freem(m);
   1762 			if (opts)
   1763 				m_freem(opts);
   1764 		} else
   1765 			sorwakeup(last->in6p_socket);
   1766 	} else {
   1767 		m_freem(m);
   1768 		ip6stat.ip6s_delivered--;
   1769 	}
   1770 	return IPPROTO_DONE;
   1771 }
   1772 
   1773 /*
   1774  * Reflect the ip6 packet back to the source.
   1775  * OFF points to the icmp6 header, counted from the top of the mbuf.
   1776  */
   1777 void
   1778 icmp6_reflect(m, off)
   1779 	struct	mbuf *m;
   1780 	size_t off;
   1781 {
   1782 	struct ip6_hdr *ip6;
   1783 	struct icmp6_hdr *icmp6;
   1784 	struct in6_ifaddr *ia;
   1785 	struct in6_addr t, *src = 0;
   1786 	int plen;
   1787 	int type, code;
   1788 	struct ifnet *outif = NULL;
   1789 #ifdef COMPAT_RFC1885
   1790 	int mtu = IPV6_MMTU;
   1791 	struct sockaddr_in6 *sin6 = &icmp6_reflect_rt.ro_dst;
   1792 #endif
   1793 
   1794 	/* too short to reflect */
   1795 	if (off < sizeof(struct ip6_hdr)) {
   1796 		printf("sanity fail: off=%lx, sizeof(ip6)=%lx in %s:%d\n",
   1797 		       (u_long)off, (u_long)sizeof(struct ip6_hdr),
   1798 		       __FILE__, __LINE__);
   1799 		goto bad;
   1800 	}
   1801 
   1802 	/*
   1803 	 * If there are extra headers between IPv6 and ICMPv6, strip
   1804 	 * off that header first.
   1805 	 */
   1806 #ifdef DIAGNOSTIC
   1807 	if (sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) > MHLEN)
   1808 		panic("assumption failed in icmp6_reflect");
   1809 #endif
   1810 	if (off > sizeof(struct ip6_hdr)) {
   1811 		size_t l;
   1812 		struct ip6_hdr nip6;
   1813 
   1814 		l = off - sizeof(struct ip6_hdr);
   1815 		m_copydata(m, 0, sizeof(nip6), (caddr_t)&nip6);
   1816 		m_adj(m, l);
   1817 		l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
   1818 		if (m->m_len < l) {
   1819 			if ((m = m_pullup(m, l)) == NULL)
   1820 				return;
   1821 		}
   1822 		bcopy((caddr_t)&nip6, mtod(m, caddr_t), sizeof(nip6));
   1823 	} else /* off == sizeof(struct ip6_hdr) */ {
   1824 		size_t l;
   1825 		l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
   1826 		if (m->m_len < l) {
   1827 			if ((m = m_pullup(m, l)) == NULL)
   1828 				return;
   1829 		}
   1830 	}
   1831 	plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
   1832 	ip6 = mtod(m, struct ip6_hdr *);
   1833 	ip6->ip6_nxt = IPPROTO_ICMPV6;
   1834 	icmp6 = (struct icmp6_hdr *)(ip6 + 1);
   1835 	type = icmp6->icmp6_type; /* keep type for statistics */
   1836 	code = icmp6->icmp6_code; /* ditto. */
   1837 
   1838 	t = ip6->ip6_dst;
   1839 	/*
   1840 	 * ip6_input() drops a packet if its src is multicast.
   1841 	 * So, the src is never multicast.
   1842 	 */
   1843 	ip6->ip6_dst = ip6->ip6_src;
   1844 
   1845 	/* XXX hack for link-local addresses */
   1846 	if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
   1847 		ip6->ip6_dst.s6_addr16[1] =
   1848 			htons(m->m_pkthdr.rcvif->if_index);
   1849 	if (IN6_IS_ADDR_LINKLOCAL(&t))
   1850 		t.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
   1851 
   1852 #ifdef COMPAT_RFC1885
   1853 	/*
   1854 	 * xxx guess MTU
   1855 	 * RFC 1885 requires that echo reply should be truncated if it
   1856 	 * does not fit in with (return) path MTU, but the description was
   1857 	 * removed in the new spec.
   1858 	 */
   1859 	if (icmp6_reflect_rt.ro_rt == 0 ||
   1860 	    ! (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr, &ip6->ip6_dst))) {
   1861 		if (icmp6_reflect_rt.ro_rt) {
   1862 			icmp6_reflect_rt.ro_rt = 0;
   1863 		}
   1864 		bzero(sin6, sizeof(*sin6));
   1865 		sin6->sin6_family = PF_INET6;
   1866 		sin6->sin6_len = sizeof(struct sockaddr_in6);
   1867 		sin6->sin6_addr = ip6->ip6_dst;
   1868 
   1869 		rtalloc((struct route *)&icmp6_reflect_rt.ro_rt);
   1870 	}
   1871 
   1872 	if (icmp6_reflect_rt.ro_rt == 0)
   1873 		goto bad;
   1874 
   1875 	if ((icmp6_reflect_rt.ro_rt->rt_flags & RTF_HOST)
   1876 	    && mtu < icmp6_reflect_rt.ro_rt->rt_ifp->if_mtu)
   1877 		mtu = icmp6_reflect_rt.ro_rt->rt_rmx.rmx_mtu;
   1878 
   1879 	if (mtu < m->m_pkthdr.len) {
   1880 		plen -= (m->m_pkthdr.len - mtu);
   1881 		m_adj(m, mtu - m->m_pkthdr.len);
   1882 	}
   1883 #endif
   1884 	/*
   1885 	 * If the incoming packet was addressed directly to us(i.e. unicast),
   1886 	 * use dst as the src for the reply.
   1887 	 * The IN6_IFF_NOTREADY case would be VERY rare, but is possible
   1888 	 * (for example) when we encounter an error while forwarding procedure
   1889 	 * destined to a duplicated address of ours.
   1890 	 */
   1891 	for (ia = in6_ifaddr; ia; ia = ia->ia_next)
   1892 		if (IN6_ARE_ADDR_EQUAL(&t, &ia->ia_addr.sin6_addr) &&
   1893 		    (ia->ia6_flags & (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY)) == 0) {
   1894 			src = &t;
   1895 			break;
   1896 		}
   1897 	if (ia == NULL && IN6_IS_ADDR_LINKLOCAL(&t) && (m->m_flags & M_LOOP)) {
   1898 		/*
   1899 		 * This is the case if the dst is our link-local address
   1900 		 * and the sender is also ourseleves.
   1901 		 */
   1902 		src = &t;
   1903 	}
   1904 
   1905 	if (src == 0)
   1906 		/*
   1907 		 * This case matches to multicasts, our anycast, or unicasts
   1908 		 * that we do not own. Select a source address which has the
   1909 		 * same scope.
   1910 		 * XXX: for (non link-local) multicast addresses, this might
   1911 		 * not be a good choice.
   1912 		 */
   1913 		if ((ia = in6_ifawithscope(m->m_pkthdr.rcvif, &t)) != 0)
   1914 			src = &IA6_SIN6(ia)->sin6_addr;
   1915 
   1916 	if (src == 0)
   1917 		goto bad;
   1918 
   1919 	ip6->ip6_src = *src;
   1920 
   1921 	ip6->ip6_flow = 0;
   1922 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
   1923 	ip6->ip6_vfc |= IPV6_VERSION;
   1924 	ip6->ip6_nxt = IPPROTO_ICMPV6;
   1925 	if (m->m_pkthdr.rcvif) {
   1926 		/* XXX: This may not be the outgoing interface */
   1927 		ip6->ip6_hlim = nd_ifinfo[m->m_pkthdr.rcvif->if_index].chlim;
   1928 	}
   1929 
   1930 	icmp6->icmp6_cksum = 0;
   1931 	icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
   1932 					sizeof(struct ip6_hdr), plen);
   1933 
   1934 	/*
   1935 	 * xxx option handling
   1936 	 */
   1937 
   1938 	m->m_flags &= ~(M_BCAST|M_MCAST);
   1939 #ifdef IPSEC
   1940 	/* Don't lookup socket */
   1941 	ipsec_setsocket(m, NULL);
   1942 #endif /*IPSEC*/
   1943 
   1944 #ifdef COMPAT_RFC1885
   1945 	ip6_output(m, NULL, &icmp6_reflect_rt, 0, NULL, &outif);
   1946 #else
   1947 	ip6_output(m, NULL, NULL, 0, NULL, &outif);
   1948 #endif
   1949 	if (outif)
   1950 		icmp6_ifoutstat_inc(outif, type, code);
   1951 
   1952 	return;
   1953 
   1954  bad:
   1955 	m_freem(m);
   1956 	return;
   1957 }
   1958 
   1959 void
   1960 icmp6_fasttimo()
   1961 {
   1962 
   1963 	mld6_fasttimeo();
   1964 
   1965 	/* reset ICMPv6 pps limit */
   1966 	icmp6errpps_count = 0;
   1967 }
   1968 
   1969 static const char *
   1970 icmp6_redirect_diag(src6, dst6, tgt6)
   1971 	struct in6_addr *src6;
   1972 	struct in6_addr *dst6;
   1973 	struct in6_addr *tgt6;
   1974 {
   1975 	static char buf[1024];
   1976 	snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
   1977 		ip6_sprintf(src6), ip6_sprintf(dst6), ip6_sprintf(tgt6));
   1978 	return buf;
   1979 }
   1980 
   1981 void
   1982 icmp6_redirect_input(m, off)
   1983 	register struct mbuf *m;
   1984 	int off;
   1985 {
   1986 	struct ifnet *ifp = m->m_pkthdr.rcvif;
   1987 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
   1988 	struct nd_redirect *nd_rd;
   1989 	int icmp6len = ntohs(ip6->ip6_plen);
   1990 	char *lladdr = NULL;
   1991 	int lladdrlen = 0;
   1992 	u_char *redirhdr = NULL;
   1993 	int redirhdrlen = 0;
   1994 	struct rtentry *rt = NULL;
   1995 	int is_router;
   1996 	int is_onlink;
   1997 	struct in6_addr src6 = ip6->ip6_src;
   1998 	struct in6_addr redtgt6;
   1999 	struct in6_addr reddst6;
   2000 	union nd_opts ndopts;
   2001 
   2002 	if (!m || !ifp)
   2003 		return;
   2004 
   2005 	/* XXX if we are router, we don't update route by icmp6 redirect */
   2006 	if (ip6_forwarding)
   2007 		goto freeit;
   2008 	if (!icmp6_rediraccept)
   2009 		goto freeit;
   2010 
   2011 #ifndef PULLDOWN_TEST
   2012 	IP6_EXTHDR_CHECK(m, off, icmp6len,);
   2013 	nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
   2014 #else
   2015 	IP6_EXTHDR_GET(nd_rd, struct nd_redirect *, m, off, icmp6len);
   2016 	if (nd_rd == NULL) {
   2017 		icmp6stat.icp6s_tooshort++;
   2018 		return;
   2019 	}
   2020 #endif
   2021 	redtgt6 = nd_rd->nd_rd_target;
   2022 	reddst6 = nd_rd->nd_rd_dst;
   2023 
   2024 	if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
   2025 		redtgt6.s6_addr16[1] = htons(ifp->if_index);
   2026 	if (IN6_IS_ADDR_LINKLOCAL(&reddst6))
   2027 		reddst6.s6_addr16[1] = htons(ifp->if_index);
   2028 
   2029 	/* validation */
   2030 	if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
   2031 		log(LOG_ERR,
   2032 			"ICMP6 redirect sent from %s rejected; "
   2033 			"must be from linklocal\n", ip6_sprintf(&src6));
   2034 		goto freeit;
   2035 	}
   2036 	if (ip6->ip6_hlim != 255) {
   2037 		log(LOG_ERR,
   2038 			"ICMP6 redirect sent from %s rejected; "
   2039 			"hlim=%d (must be 255)\n",
   2040 			ip6_sprintf(&src6), ip6->ip6_hlim);
   2041 		goto freeit;
   2042 	}
   2043     {
   2044 	/* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
   2045 	struct sockaddr_in6 sin6;
   2046 	struct in6_addr *gw6;
   2047 
   2048 	bzero(&sin6, sizeof(sin6));
   2049 	sin6.sin6_family = AF_INET6;
   2050 	sin6.sin6_len = sizeof(struct sockaddr_in6);
   2051 	bcopy(&reddst6, &sin6.sin6_addr, sizeof(reddst6));
   2052 	rt = rtalloc1((struct sockaddr *)&sin6, 0);
   2053 	if (rt) {
   2054 		gw6 = &(((struct sockaddr_in6 *)rt->rt_gateway)->sin6_addr);
   2055 		if (bcmp(&src6, gw6, sizeof(struct in6_addr)) != 0) {
   2056 			log(LOG_ERR,
   2057 				"ICMP6 redirect rejected; "
   2058 				"not equal to gw-for-src=%s (must be same): "
   2059 				"%s\n",
   2060 				ip6_sprintf(gw6),
   2061 				icmp6_redirect_diag(&src6, &reddst6, &redtgt6));
   2062 			RTFREE(rt);
   2063 			goto freeit;
   2064 		}
   2065 	} else {
   2066 		log(LOG_ERR,
   2067 			"ICMP6 redirect rejected; "
   2068 			"no route found for redirect dst: %s\n",
   2069 			icmp6_redirect_diag(&src6, &reddst6, &redtgt6));
   2070 		goto freeit;
   2071 	}
   2072 	RTFREE(rt);
   2073 	rt = NULL;
   2074     }
   2075 	if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
   2076 		log(LOG_ERR,
   2077 			"ICMP6 redirect rejected; "
   2078 			"redirect dst must be unicast: %s\n",
   2079 			icmp6_redirect_diag(&src6, &reddst6, &redtgt6));
   2080 		goto freeit;
   2081 	}
   2082 
   2083 	is_router = is_onlink = 0;
   2084 	if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
   2085 		is_router = 1;	/* router case */
   2086 	if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
   2087 		is_onlink = 1;	/* on-link destination case */
   2088 	if (!is_router && !is_onlink) {
   2089 		log(LOG_ERR,
   2090 			"ICMP6 redirect rejected; "
   2091 			"neither router case nor onlink case: %s\n",
   2092 			icmp6_redirect_diag(&src6, &reddst6, &redtgt6));
   2093 		goto freeit;
   2094 	}
   2095 	/* validation passed */
   2096 
   2097 	icmp6len -= sizeof(*nd_rd);
   2098 	nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
   2099 	if (nd6_options(&ndopts) < 0) {
   2100 		log(LOG_INFO, "icmp6_redirect_input: "
   2101 			"invalid ND option, rejected: %s\n",
   2102 			icmp6_redirect_diag(&src6, &reddst6, &redtgt6));
   2103 		goto freeit;
   2104 	}
   2105 
   2106 	if (ndopts.nd_opts_tgt_lladdr) {
   2107 		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
   2108 		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
   2109 	}
   2110 
   2111 	if (ndopts.nd_opts_rh) {
   2112 		redirhdrlen = ndopts.nd_opts_rh->nd_opt_rh_len;
   2113 		redirhdr = (u_char *)(ndopts.nd_opts_rh + 1); /* xxx */
   2114 	}
   2115 
   2116 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
   2117 		log(LOG_INFO,
   2118 			"icmp6_redirect_input: lladdrlen mismatch for %s "
   2119 			"(if %d, icmp6 packet %d): %s\n",
   2120 			ip6_sprintf(&redtgt6), ifp->if_addrlen, lladdrlen - 2,
   2121 			icmp6_redirect_diag(&src6, &reddst6, &redtgt6));
   2122 	}
   2123 
   2124 	/* RFC 2461 8.3 */
   2125 	nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
   2126 			 is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
   2127 
   2128 	if (!is_onlink) {	/* better router case. perform rtredirect. */
   2129 		/* perform rtredirect */
   2130 		struct sockaddr_in6 sdst;
   2131 		struct sockaddr_in6 sgw;
   2132 		struct sockaddr_in6 ssrc;
   2133 
   2134 		bzero(&sdst, sizeof(sdst));
   2135 		bzero(&sgw, sizeof(sgw));
   2136 		bzero(&ssrc, sizeof(ssrc));
   2137 		sdst.sin6_family = sgw.sin6_family = ssrc.sin6_family = AF_INET6;
   2138 		sdst.sin6_len = sgw.sin6_len = ssrc.sin6_len =
   2139 			sizeof(struct sockaddr_in6);
   2140 		bcopy(&redtgt6, &sgw.sin6_addr, sizeof(struct in6_addr));
   2141 		bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
   2142 		bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
   2143 		rtredirect((struct sockaddr *)&sdst, (struct sockaddr *)&sgw,
   2144 			   (struct sockaddr *)NULL, RTF_GATEWAY | RTF_HOST,
   2145 			   (struct sockaddr *)&ssrc,
   2146 			   (struct rtentry **)NULL
   2147 			   );
   2148 	}
   2149 	/* finally update cached route in each socket via pfctlinput */
   2150     {
   2151 	struct sockaddr_in6 sdst;
   2152 #if 1
   2153 #else
   2154 	struct ip6protosw *pr;
   2155 #endif
   2156 
   2157 	bzero(&sdst, sizeof(sdst));
   2158 	sdst.sin6_family = AF_INET6;
   2159 	sdst.sin6_len = sizeof(struct sockaddr_in6);
   2160 	bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
   2161 #if 1
   2162 	pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&sdst);
   2163 #else
   2164 	/*
   2165 	 * do not use pfctlinput() here, we have different prototype for
   2166 	 * xx_ctlinput() in ip6proto.
   2167 	 */
   2168 	for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
   2169 	     pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW;
   2170 	     pr++) {
   2171 		if (pr->pr_ctlinput) {
   2172 			(*pr->pr_ctlinput)(PRC_REDIRECT_HOST,
   2173 				(struct sockaddr *)&sdst, NULL, NULL, 0);
   2174 		}
   2175 	}
   2176 #endif
   2177 #ifdef IPSEC
   2178 	key_sa_routechange((struct sockaddr *)&sdst);
   2179 #endif
   2180     }
   2181 
   2182  freeit:
   2183 	m_freem(m);
   2184 }
   2185 
   2186 void
   2187 icmp6_redirect_output(m0, rt)
   2188 	struct mbuf *m0;
   2189 	struct rtentry *rt;
   2190 {
   2191 	struct ifnet *ifp;	/* my outgoing interface */
   2192 	struct in6_addr *ifp_ll6;
   2193 	struct in6_addr *router_ll6;
   2194 	struct ip6_hdr *sip6;	/* m0 as struct ip6_hdr */
   2195 	struct mbuf *m = NULL;	/* newly allocated one */
   2196 	struct ip6_hdr *ip6;	/* m as struct ip6_hdr */
   2197 	struct nd_redirect *nd_rd;
   2198 	size_t maxlen;
   2199 	u_char *p;
   2200 	struct ifnet *outif = NULL;
   2201 	struct sockaddr_in6 src_sa;
   2202 
   2203 	icmp6_errcount(&icmp6stat.icp6s_outerrhist, ND_REDIRECT, 0);
   2204 
   2205 	/* if we are not router, we don't send icmp6 redirect */
   2206 	if (!ip6_forwarding || ip6_accept_rtadv)
   2207 		goto fail;
   2208 
   2209 	/* sanity check */
   2210 	if (!m0 || !rt || !(rt->rt_flags & RTF_UP) || !(ifp = rt->rt_ifp))
   2211 		goto fail;
   2212 
   2213 	/*
   2214 	 * Address check:
   2215 	 *  the source address must identify a neighbor, and
   2216 	 *  the destination address must not be a multicast address
   2217 	 *  [RFC 2461, sec 8.2]
   2218 	 */
   2219 	sip6 = mtod(m0, struct ip6_hdr *);
   2220 	bzero(&src_sa, sizeof(src_sa));
   2221 	src_sa.sin6_family = AF_INET6;
   2222 	src_sa.sin6_len = sizeof(src_sa);
   2223 	src_sa.sin6_addr = sip6->ip6_src;
   2224 	/* we don't currently use sin6_scope_id, but eventually use it */
   2225 	src_sa.sin6_scope_id = in6_addr2scopeid(ifp, &sip6->ip6_src);
   2226 	if (nd6_is_addr_neighbor(&src_sa, ifp) == 0)
   2227 		goto fail;
   2228 	if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
   2229 		goto fail;	/* what should we do here? */
   2230 
   2231 	/* rate limit */
   2232 	if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
   2233 		goto fail;
   2234 
   2235 	/*
   2236 	 * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
   2237 	 * we almost always ask for an mbuf cluster for simplicity.
   2238 	 * (MHLEN < IPV6_MMTU is almost always true)
   2239 	 */
   2240 #if IPV6_MMTU >= MCLBYTES
   2241 # error assumption failed about IPV6_MMTU and MCLBYTES
   2242 #endif
   2243 	MGETHDR(m, M_DONTWAIT, MT_HEADER);
   2244 	if (m && IPV6_MMTU >= MHLEN)
   2245 		MCLGET(m, M_DONTWAIT);
   2246 	if (!m)
   2247 		goto fail;
   2248 	maxlen = (m->m_flags & M_EXT) ? MCLBYTES : MHLEN;
   2249 	maxlen = min(IPV6_MMTU, maxlen);
   2250 	/* just for safety */
   2251 	if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) +
   2252 	    ((sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7)) {
   2253 		goto fail;
   2254 	}
   2255 
   2256 	{
   2257 		/* get ip6 linklocal address for ifp(my outgoing interface). */
   2258 		struct in6_ifaddr *ia;
   2259 		if ((ia = in6ifa_ifpforlinklocal(ifp,
   2260 						 IN6_IFF_NOTREADY|
   2261 						 IN6_IFF_ANYCAST)) == NULL)
   2262 			goto fail;
   2263 		ifp_ll6 = &ia->ia_addr.sin6_addr;
   2264 	}
   2265 
   2266 	/* get ip6 linklocal address for the router. */
   2267 	if (rt->rt_gateway && (rt->rt_flags & RTF_GATEWAY)) {
   2268 		struct sockaddr_in6 *sin6;
   2269 		sin6 = (struct sockaddr_in6 *)rt->rt_gateway;
   2270 		router_ll6 = &sin6->sin6_addr;
   2271 		if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
   2272 			router_ll6 = (struct in6_addr *)NULL;
   2273 	} else
   2274 		router_ll6 = (struct in6_addr *)NULL;
   2275 
   2276 	/* ip6 */
   2277 	ip6 = mtod(m, struct ip6_hdr *);
   2278 	ip6->ip6_flow = 0;
   2279 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
   2280 	ip6->ip6_vfc |= IPV6_VERSION;
   2281 	/* ip6->ip6_plen will be set later */
   2282 	ip6->ip6_nxt = IPPROTO_ICMPV6;
   2283 	ip6->ip6_hlim = 255;
   2284 	/* ip6->ip6_src must be linklocal addr for my outgoing if. */
   2285 	bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
   2286 	bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));
   2287 
   2288 	/* ND Redirect */
   2289 	nd_rd = (struct nd_redirect *)(ip6 + 1);
   2290 	nd_rd->nd_rd_type = ND_REDIRECT;
   2291 	nd_rd->nd_rd_code = 0;
   2292 	nd_rd->nd_rd_reserved = 0;
   2293 	if (rt->rt_flags & RTF_GATEWAY) {
   2294 		/*
   2295 		 * nd_rd->nd_rd_target must be a link-local address in
   2296 		 * better router cases.
   2297 		 */
   2298 		if (!router_ll6)
   2299 			goto fail;
   2300 		bcopy(router_ll6, &nd_rd->nd_rd_target,
   2301 		      sizeof(nd_rd->nd_rd_target));
   2302 		bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
   2303 		      sizeof(nd_rd->nd_rd_dst));
   2304 	} else {
   2305 		/* make sure redtgt == reddst */
   2306 		bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
   2307 		      sizeof(nd_rd->nd_rd_target));
   2308 		bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
   2309 		      sizeof(nd_rd->nd_rd_dst));
   2310 	}
   2311 
   2312 	p = (u_char *)(nd_rd + 1);
   2313 
   2314 	if (!router_ll6)
   2315 		goto nolladdropt;
   2316 
   2317     {
   2318 	/* target lladdr option */
   2319 	struct rtentry *rt_router = NULL;
   2320 	int len;
   2321 	struct sockaddr_dl *sdl;
   2322 	struct nd_opt_hdr *nd_opt;
   2323 	char *lladdr;
   2324 
   2325 	rt_router = nd6_lookup(router_ll6, 0, ifp);
   2326 	if (!rt_router)
   2327 		goto nolladdropt;
   2328 	len = sizeof(*nd_opt) + ifp->if_addrlen;
   2329 	len = (len + 7) & ~7;	/*round by 8*/
   2330 	/* safety check */
   2331 	if (len + (p - (u_char *)ip6) > maxlen)
   2332 		goto nolladdropt;
   2333 	if (!(rt_router->rt_flags & RTF_GATEWAY) &&
   2334 	    (rt_router->rt_flags & RTF_LLINFO) &&
   2335 	    (rt_router->rt_gateway->sa_family == AF_LINK) &&
   2336 	    (sdl = (struct sockaddr_dl *)rt_router->rt_gateway) &&
   2337 	    sdl->sdl_alen) {
   2338 		nd_opt = (struct nd_opt_hdr *)p;
   2339 		nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
   2340 		nd_opt->nd_opt_len = len >> 3;
   2341 		lladdr = (char *)(nd_opt + 1);
   2342 		bcopy(LLADDR(sdl), lladdr, ifp->if_addrlen);
   2343 		p += len;
   2344 	}
   2345     }
   2346 nolladdropt:;
   2347 
   2348 	m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
   2349 
   2350 	/* just to be safe */
   2351 	if (m0->m_flags & M_DECRYPTED)
   2352 		goto noredhdropt;
   2353 	if (p - (u_char *)ip6 > maxlen)
   2354 		goto noredhdropt;
   2355 
   2356     {
   2357 	/* redirected header option */
   2358 	int len;
   2359 	struct nd_opt_rd_hdr *nd_opt_rh;
   2360 
   2361 	/*
   2362 	 * compute the maximum size for icmp6 redirect header option.
   2363 	 * XXX room for auth header?
   2364 	 */
   2365 	len = maxlen - (p - (u_char *)ip6);
   2366 	len &= ~7;
   2367 
   2368 	/* This is just for simplicity. */
   2369 	if (m0->m_pkthdr.len != m0->m_len) {
   2370 		if (m0->m_next) {
   2371 			m_freem(m0->m_next);
   2372 			m0->m_next = NULL;
   2373 		}
   2374 		m0->m_pkthdr.len = m0->m_len;
   2375 	}
   2376 
   2377 	/*
   2378 	 * Redirected header option spec (RFC2461 4.6.3) talks nothing
   2379 	 * about padding/truncate rule for the original IP packet.
   2380 	 * From the discussion on IPv6imp in Feb 1999, the consensus was:
   2381 	 * - "attach as much as possible" is the goal
   2382 	 * - pad if not aligned (original size can be guessed by original
   2383 	 *   ip6 header)
   2384 	 * Following code adds the padding if it is simple enough,
   2385 	 * and truncates if not.
   2386 	 */
   2387 	if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
   2388 		panic("assumption failed in %s:%d\n", __FILE__, __LINE__);
   2389 
   2390 	if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
   2391 		/* not enough room, truncate */
   2392 		m0->m_pkthdr.len = m0->m_len = len - sizeof(*nd_opt_rh);
   2393 	} else {
   2394 		/* enough room, pad or truncate */
   2395 		size_t extra;
   2396 
   2397 		extra = m0->m_pkthdr.len % 8;
   2398 		if (extra) {
   2399 			/* pad if easy enough, truncate if not */
   2400 			if (8 - extra <= M_TRAILINGSPACE(m0)) {
   2401 				/* pad */
   2402 				m0->m_len += (8 - extra);
   2403 				m0->m_pkthdr.len += (8 - extra);
   2404 			} else {
   2405 				/* truncate */
   2406 				m0->m_pkthdr.len -= extra;
   2407 				m0->m_len -= extra;
   2408 			}
   2409 		}
   2410 		len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
   2411 		m0->m_pkthdr.len = m0->m_len = len - sizeof(*nd_opt_rh);
   2412 	}
   2413 
   2414 	nd_opt_rh = (struct nd_opt_rd_hdr *)p;
   2415 	bzero(nd_opt_rh, sizeof(*nd_opt_rh));
   2416 	nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
   2417 	nd_opt_rh->nd_opt_rh_len = len >> 3;
   2418 	p += sizeof(*nd_opt_rh);
   2419 	m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
   2420 
   2421 	/* connect m0 to m */
   2422 	m->m_next = m0;
   2423 	m->m_pkthdr.len = m->m_len + m0->m_len;
   2424     }
   2425 noredhdropt:;
   2426 
   2427 	if (IN6_IS_ADDR_LINKLOCAL(&sip6->ip6_src))
   2428 		sip6->ip6_src.s6_addr16[1] = 0;
   2429 	if (IN6_IS_ADDR_LINKLOCAL(&sip6->ip6_dst))
   2430 		sip6->ip6_dst.s6_addr16[1] = 0;
   2431 #if 0
   2432 	if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
   2433 		ip6->ip6_src.s6_addr16[1] = 0;
   2434 	if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
   2435 		ip6->ip6_dst.s6_addr16[1] = 0;
   2436 #endif
   2437 	if (IN6_IS_ADDR_LINKLOCAL(&nd_rd->nd_rd_target))
   2438 		nd_rd->nd_rd_target.s6_addr16[1] = 0;
   2439 	if (IN6_IS_ADDR_LINKLOCAL(&nd_rd->nd_rd_dst))
   2440 		nd_rd->nd_rd_dst.s6_addr16[1] = 0;
   2441 
   2442 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
   2443 
   2444 	nd_rd->nd_rd_cksum = 0;
   2445 	nd_rd->nd_rd_cksum
   2446 		= in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), ntohs(ip6->ip6_plen));
   2447 
   2448 	/* send the packet to outside... */
   2449 #ifdef IPSEC
   2450 	/* Don't lookup socket */
   2451 	ipsec_setsocket(m, NULL);
   2452 #endif /*IPSEC*/
   2453 	ip6_output(m, NULL, NULL, 0, NULL, &outif);
   2454 	if (outif) {
   2455 		icmp6_ifstat_inc(outif, ifs6_out_msg);
   2456 		icmp6_ifstat_inc(outif, ifs6_out_redirect);
   2457 	}
   2458 	icmp6stat.icp6s_outhist[ND_REDIRECT]++;
   2459 
   2460 	return;
   2461 
   2462 fail:
   2463 	if (m)
   2464 		m_freem(m);
   2465 	if (m0)
   2466 		m_freem(m0);
   2467 }
   2468 
   2469 /*
   2470  * ICMPv6 socket option processing.
   2471  */
   2472 int
   2473 icmp6_ctloutput(op, so, level, optname, mp)
   2474 	int op;
   2475 	struct socket *so;
   2476 	int level, optname;
   2477 	struct mbuf **mp;
   2478 {
   2479 	register struct in6pcb *in6p = sotoin6pcb(so);
   2480 	register struct mbuf *m = *mp;
   2481 	int error = 0;
   2482 
   2483 	if (level != IPPROTO_ICMPV6) {
   2484 		error = EINVAL;
   2485 		if (op == PRCO_SETOPT && m)
   2486 			(void)m_free(m);
   2487 	} else switch(op) {
   2488 	 case PRCO_SETOPT:
   2489 		 switch (optname) {
   2490 		  case ICMP6_FILTER:
   2491 		  {
   2492 			  struct icmp6_filter *p;
   2493 
   2494 			  p = mtod(m, struct icmp6_filter *);
   2495 			  if (!p || !in6p->in6p_icmp6filt) {
   2496 				  error = EINVAL;
   2497 				  break;
   2498 			  }
   2499 			  bcopy(p, in6p->in6p_icmp6filt,
   2500 				sizeof(struct icmp6_filter));
   2501 			  error = 0;
   2502 			  break;
   2503 		  }
   2504 
   2505 		  default:
   2506 			  error = ENOPROTOOPT;
   2507 			  break;
   2508 		 }
   2509 		 if (m)
   2510 			 (void)m_free(m);
   2511 		 break;
   2512 
   2513 	 case PRCO_GETOPT:
   2514 		 switch (optname) {
   2515 		  case ICMP6_FILTER:
   2516 		  {
   2517 			  struct icmp6_filter *p;
   2518 
   2519 			  if (!in6p->in6p_icmp6filt) {
   2520 				  error = EINVAL;
   2521 				  break;
   2522 			  }
   2523 			  *mp = m = m_get(M_WAIT, MT_SOOPTS);
   2524 			  m->m_len = sizeof(struct icmp6_filter);
   2525 			  p = mtod(m, struct icmp6_filter *);
   2526 			  bcopy(in6p->in6p_icmp6filt, p,
   2527 				sizeof(struct icmp6_filter));
   2528 			  error = 0;
   2529 			  break;
   2530 		  }
   2531 
   2532 		  default:
   2533 			  error = ENOPROTOOPT;
   2534 			  break;
   2535 		 }
   2536 		 break;
   2537 	}
   2538 
   2539 	return(error);
   2540 }
   2541 
   2542 /*
   2543  * Perform rate limit check.
   2544  * Returns 0 if it is okay to send the icmp6 packet.
   2545  * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
   2546  * limitation.
   2547  *
   2548  * There are two limitations defined:
   2549  * - pps limit: ICMPv6 error packet cannot exceed defined packet-per-second.
   2550  *   we measure it every 0.2 second, since fasttimo works every 0.2 second.
   2551  * - rate limit: ICMPv6 error packet cannot appear more than once per
   2552  *   defined interval.
   2553  * In any case, if we perform rate limitation, we'll see jitter in the ICMPv6
   2554  * error packets.
   2555  *
   2556  * XXX per-destination/type check necessary?
   2557  */
   2558 static int
   2559 icmp6_ratelimit(dst, type, code)
   2560 	const struct in6_addr *dst;	/* not used at this moment */
   2561 	const int type;			/* not used at this moment */
   2562 	const int code;			/* not used at this moment */
   2563 {
   2564 	int ret;
   2565 
   2566 	ret = 0;	/*okay to send*/
   2567 
   2568 	/* PPS limit */
   2569 	icmp6errpps_count++;
   2570 	if (icmp6errppslim && icmp6errpps_count > icmp6errppslim / 5) {
   2571 		/* The packet is subject to pps limit */
   2572 		ret++;
   2573 	}
   2574 
   2575 	if (!ratecheck(&icmp6errratelim_last, &icmp6errratelim)) {
   2576 		/* The packet is subject to rate limit */
   2577 		ret++;
   2578 	}
   2579 
   2580 	return ret;
   2581 }
   2582 
   2583 static struct rtentry *
   2584 icmp6_mtudisc_clone(dst)
   2585 	struct sockaddr *dst;
   2586 {
   2587 	struct rtentry *rt;
   2588 	int    error;
   2589 
   2590 	rt = rtalloc1(dst, 1);
   2591 	if (rt == 0)
   2592 		return NULL;
   2593 
   2594 	/* If we didn't get a host route, allocate one */
   2595 	if ((rt->rt_flags & RTF_HOST) == 0) {
   2596 		struct rtentry *nrt;
   2597 
   2598 		error = rtrequest((int) RTM_ADD, dst,
   2599 		    (struct sockaddr *) rt->rt_gateway,
   2600 		    (struct sockaddr *) 0,
   2601 		    RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt);
   2602 		if (error) {
   2603 			rtfree(rt);
   2604 			rtfree(nrt);
   2605 			return NULL;
   2606 		}
   2607 		nrt->rt_rmx = rt->rt_rmx;
   2608 		rtfree(rt);
   2609 		rt = nrt;
   2610 	}
   2611 	error = rt_timer_add(rt, icmp6_mtudisc_timeout,
   2612 			icmp6_mtudisc_timeout_q);
   2613 	if (error) {
   2614 		rtfree(rt);
   2615 		return NULL;
   2616 	}
   2617 
   2618 	return rt;	/* caller need to call rtfree() */
   2619 }
   2620 
   2621 static void
   2622 icmp6_mtudisc_timeout(rt, r)
   2623 	struct rtentry *rt;
   2624 	struct rttimer *r;
   2625 {
   2626 	if (rt == NULL)
   2627 		panic("icmp6_mtudisc_timeout: bad route to timeout");
   2628 	if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) ==
   2629 	    (RTF_DYNAMIC | RTF_HOST)) {
   2630 		rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
   2631 		    rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
   2632 	} else {
   2633 		if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) {
   2634 			rt->rt_rmx.rmx_mtu = 0;
   2635 		}
   2636 	}
   2637 }
   2638 
   2639 #include <uvm/uvm_extern.h>
   2640 #include <sys/sysctl.h>
   2641 
   2642 int
   2643 icmp6_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
   2644 	int *name;
   2645 	u_int namelen;
   2646 	void *oldp;
   2647 	size_t *oldlenp;
   2648 	void *newp;
   2649 	size_t newlen;
   2650 {
   2651 
   2652 	/* All sysctl names at this level are terminal. */
   2653 	if (namelen != 1)
   2654 		return ENOTDIR;
   2655 
   2656 	switch (name[0]) {
   2657 
   2658 	case ICMPV6CTL_REDIRACCEPT:
   2659 		return sysctl_int(oldp, oldlenp, newp, newlen,
   2660 				&icmp6_rediraccept);
   2661 	case ICMPV6CTL_REDIRTIMEOUT:
   2662 		return sysctl_int(oldp, oldlenp, newp, newlen,
   2663 				&icmp6_redirtimeout);
   2664 	case ICMPV6CTL_STATS:
   2665 		return sysctl_rdstruct(oldp, oldlenp, newp,
   2666 				&icmp6stat, sizeof(icmp6stat));
   2667 	case ICMPV6CTL_ERRRATELIMIT:
   2668 	    {
   2669 		int rate_usec, error, s;
   2670 
   2671 		/*
   2672 		 * The sysctl specifies the rate in usec-between-icmp,
   2673 		 * so we must convert from/to a timeval.
   2674 		 */
   2675 		rate_usec = (icmp6errratelim.tv_sec * 1000000) +
   2676 		    icmp6errratelim.tv_usec;
   2677 		error = sysctl_int(oldp, oldlenp, newp, newlen, &rate_usec);
   2678 		if (error)
   2679 			return (error);
   2680 		if (rate_usec < 0)
   2681 			return (EINVAL);
   2682 		s = splsoftnet();
   2683 		icmp6errratelim.tv_sec = rate_usec / 1000000;
   2684 		icmp6errratelim.tv_usec = rate_usec % 1000000;
   2685 		splx(s);
   2686 
   2687 		return (0);
   2688 	    }
   2689 	case ICMPV6CTL_ND6_PRUNE:
   2690 		return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_prune);
   2691 	case ICMPV6CTL_ND6_DELAY:
   2692 		return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_delay);
   2693 	case ICMPV6CTL_ND6_UMAXTRIES:
   2694 		return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_umaxtries);
   2695 	case ICMPV6CTL_ND6_MMAXTRIES:
   2696 		return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_mmaxtries);
   2697 	case ICMPV6CTL_ND6_USELOOPBACK:
   2698 		return sysctl_int(oldp, oldlenp, newp, newlen,
   2699 				&nd6_useloopback);
   2700 	case ICMPV6CTL_NODEINFO:
   2701 		return sysctl_int(oldp, oldlenp, newp, newlen, &icmp6_nodeinfo);
   2702 	case ICMPV6CTL_ERRPPSLIMIT:
   2703 		return sysctl_int(oldp, oldlenp, newp, newlen, &icmp6errppslim);
   2704 	case ICMPV6CTL_ND6_MAXNUDHINT:
   2705 		return sysctl_int(oldp, oldlenp, newp, newlen,
   2706 				&nd6_maxnudhint);
   2707 	default:
   2708 		return ENOPROTOOPT;
   2709 	}
   2710 	/* NOTREACHED */
   2711 }
   2712