xref: /netbsd-src/sys/netinet6/icmp6.c (revision 3b435a73967be44dfb4a27315acd72bfacde430c)
1 /*	$NetBSD: icmp6.c,v 1.11 1999/10/01 10:16:16 itojun Exp $	*/
2 
3 /*
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * Copyright (c) 1982, 1986, 1988, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  * 3. All advertising materials mentioning features or use of this software
45  *    must display the following acknowledgement:
46  *	This product includes software developed by the University of
47  *	California, Berkeley and its contributors.
48  * 4. Neither the name of the University nor the names of its contributors
49  *    may be used to endorse or promote products derived from this software
50  *    without specific prior written permission.
51  *
52  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62  * SUCH DAMAGE.
63  *
64  *	@(#)ip_icmp.c	8.2 (Berkeley) 1/4/94
65  */
66 
67 #if (defined(__FreeBSD__) && __FreeBSD__ >= 3) || defined(__NetBSD__)
68 #include "opt_inet.h"
69 #ifdef __NetBSD__	/*XXX*/
70 #include "opt_ipsec.h"
71 #endif
72 #endif
73 
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/malloc.h>
77 #include <sys/mbuf.h>
78 #include <sys/protosw.h>
79 #include <sys/socket.h>
80 #include <sys/socketvar.h>
81 #include <sys/time.h>
82 #include <sys/kernel.h>
83 #include <sys/syslog.h>
84 
85 #include <net/if.h>
86 #include <net/route.h>
87 #include <net/if_dl.h>
88 #include <net/if_types.h>
89 
90 #include <netinet/in.h>
91 #include <netinet/in_var.h>
92 #include <netinet6/ip6.h>
93 #include <netinet6/ip6_var.h>
94 #include <netinet6/icmp6.h>
95 #include <netinet6/mld6_var.h>
96 #if !defined(__FreeBSD__) || __FreeBSD__ < 3
97 #include <netinet6/in6_pcb.h>
98 #else
99 #include <netinet/in_pcb.h>
100 #endif
101 #include <netinet6/nd6.h>
102 #include <netinet6/in6_ifattach.h>
103 #include <netinet6/ip6protosw.h>
104 
105 #ifdef IPSEC
106 #include <netkey/key.h>
107 #include <netkey/key_debug.h>
108 #endif
109 
110 #include "faith.h"
111 
112 extern struct ip6protosw inet6sw[];
113 extern u_char ip6_protox[];
114 
115 struct icmp6stat icmp6stat;
116 
117 #if !defined(__FreeBSD__) || __FreeBSD__ < 3
118 extern struct in6pcb rawin6pcb;
119 #else
120 extern struct inpcbhead ripcb;
121 #endif
122 extern u_int icmp6errratelim;
123 #ifdef __NetBSD__
124 static struct rttimer_queue *icmp6_mtudisc_timeout_q = NULL;
125 extern int pmtu_expire;
126 #endif
127 
128 static int icmp6_rip6_input __P((struct mbuf **, int));
129 static int icmp6_ratelimit __P((const struct in6_addr *, const int, const int));
130 static void icmp6_redirect_diag __P((int, struct in6_addr *, struct in6_addr *,
131 	struct in6_addr *));
132 static struct mbuf * ni6_input __P((struct mbuf *, int));
133 static int ni6_addrs __P((struct icmp6_nodeinfo *, struct mbuf *,
134 			  struct ifnet **));
135 static int ni6_store_addrs __P((struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
136 				struct ifnet *, int));
137 #ifdef __NetBSD__
138 static struct rtentry *icmp6_mtudisc_clone __P((struct sockaddr *));
139 static void icmp6_mtudisc_timeout __P((struct rtentry *, struct rttimer *));
140 #endif
141 
142 #ifdef COMPAT_RFC1885
143 static struct route_in6 icmp6_reflect_rt;
144 #endif
145 static struct timeval icmp6_nextsend = {0, 0};
146 
147 void
148 icmp6_init()
149 {
150 	mld6_init();
151 #ifdef __NetBSD__
152 	icmp6_mtudisc_timeout_q = rt_timer_queue_create(pmtu_expire);
153 #endif
154 }
155 
156 /*
157  * Generate an error packet of type error in response to bad IP6 packet.
158  */
159 void
160 icmp6_error(m, type, code, param)
161 	struct mbuf *m;
162 	int type, code, param;
163 {
164 	struct ip6_hdr *oip6, *nip6;
165 	struct icmp6_hdr *icmp6;
166 	u_int prep;
167 	int off;
168 	u_char nxt;
169 
170 	icmp6stat.icp6s_error++;
171 
172 	if (m->m_flags & M_DECRYPTED)
173 		goto freeit;
174 
175 	oip6 = mtod(m, struct ip6_hdr *);
176 
177 	/*
178 	 * Multicast destination check. For unrecognized option errors,
179 	 * this check has already done in ip6_unknown_opt(), so we can
180 	 * check only for other errors.
181 	 */
182 	if ((m->m_flags & (M_BCAST|M_MCAST) ||
183 	     IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
184 	    (type != ICMP6_PACKET_TOO_BIG &&
185 	     (type != ICMP6_PARAM_PROB ||
186 	      code != ICMP6_PARAMPROB_OPTION)))
187 		goto freeit;
188 
189 	/* Source address check. XXX: the case of anycast source? */
190 	if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
191 	    IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
192 		goto freeit;
193 
194 	/*
195 	 * If the erroneous packet is also an ICMP error, discard it.
196 	 */
197 	IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), );
198 	off = sizeof(struct ip6_hdr);
199 	nxt = oip6->ip6_nxt;
200 	while(1) {		/* XXX: should avoid inf. loop explicitly? */
201 		struct ip6_ext *ip6e;
202 		struct icmp6_hdr *icp;
203 
204 		switch(nxt) {
205 		case IPPROTO_IPV6:
206 		case IPPROTO_IPV4:
207 		case IPPROTO_UDP:
208 		case IPPROTO_TCP:
209 		case IPPROTO_ESP:
210 		case IPPROTO_FRAGMENT:
211 			/*
212 			 * ICMPv6 error must not be fragmented.
213 			 * XXX: but can we trust the sender?
214 			 */
215 		default:
216 			/* What if unknown header followed by ICMP error? */
217 			goto generate;
218 		case IPPROTO_ICMPV6:
219 			IP6_EXTHDR_CHECK(m, 0, off + sizeof(struct icmp6_hdr), );
220 			icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
221 			if (icp->icmp6_type < ICMP6_ECHO_REQUEST
222 			 || icp->icmp6_type == ND_REDIRECT) {
223 				/*
224 				 * ICMPv6 error
225 				 * Special case: for redirect (which is
226 				 * informational) we must not send icmp6 error.
227 				 */
228 				icmp6stat.icp6s_canterror++;
229 				goto freeit;
230 			} else {
231 				/* ICMPv6 informational */
232 				goto generate;
233 			}
234 		case IPPROTO_HOPOPTS:
235 		case IPPROTO_DSTOPTS:
236 		case IPPROTO_ROUTING:
237 		case IPPROTO_AH:
238 			IP6_EXTHDR_CHECK(m, 0, off + sizeof(struct ip6_ext), );
239 			ip6e = (struct ip6_ext *)(mtod(m, caddr_t) + off);
240 			if (nxt == IPPROTO_AH)
241 				off += (ip6e->ip6e_len + 2) << 2;
242 			else
243 				off += (ip6e->ip6e_len + 1) << 3;
244 			nxt = ip6e->ip6e_nxt;
245 			break;
246 		}
247 	}
248 
249   freeit:
250 	/*
251 	 * If we can't tell wheter or not we can generate ICMP6, free it.
252 	 */
253 	m_freem(m);
254 	return;
255 
256   generate:
257 	oip6 = mtod(m, struct ip6_hdr *); /* adjust pointer */
258 
259 	/* Finally, do rate limitation check. */
260 	if (icmp6_ratelimit(&oip6->ip6_src, type, code)) {
261 		icmp6stat.icp6s_toofreq++;
262 		goto freeit;
263 	}
264 
265 	/*
266 	 * OK, ICMP6 can be generated.
267 	 */
268 
269 	if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
270 		m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
271 
272 	prep = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
273 	M_PREPEND(m, prep, M_DONTWAIT);
274 	if (m && m->m_len < prep)
275 		m = m_pullup(m, prep);
276 	if (m == NULL) {
277 		printf("ENOBUFS in icmp6_error %d\n", __LINE__);
278 		return;
279 	}
280 
281 	nip6 = mtod(m, struct ip6_hdr *);
282 	nip6->ip6_src  = oip6->ip6_src;
283 	nip6->ip6_dst  = oip6->ip6_dst;
284 
285 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
286 		oip6->ip6_src.s6_addr16[1] = 0;
287 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
288 		oip6->ip6_dst.s6_addr16[1] = 0;
289 
290 	icmp6 = (struct icmp6_hdr *)(nip6 + 1);
291 	icmp6->icmp6_type = type;
292 	icmp6->icmp6_code = code;
293 	icmp6->icmp6_pptr = htonl((u_int32_t)param);
294 
295 	icmp6stat.icp6s_outhist[type]++;
296 	icmp6_reflect(m, sizeof(struct ip6_hdr)); /*header order: IPv6 - ICMPv6*/
297 }
298 
299 /*
300  * Process a received ICMP6 message.
301  */
302 int
303 icmp6_input(mp, offp, proto)
304 	struct mbuf **mp;
305 	int *offp, proto;
306 {
307 	struct mbuf *m = *mp, *n;
308 	struct ip6_hdr *ip6, *nip6;
309 	struct icmp6_hdr *icmp6, *nicmp6;
310 	int off = *offp;
311 	int icmp6len = m->m_pkthdr.len - *offp;
312 	int code, sum, noff;
313 	struct sockaddr_in6 icmp6src;
314 
315 	IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_hdr), IPPROTO_DONE);
316 	/* m might change if M_LOOP. So, call mtod after this */
317 
318 	/*
319 	 * Locate icmp6 structure in mbuf, and check
320 	 * that not corrupted and of at least minimum length
321 	 */
322 
323 	ip6 = mtod(m, struct ip6_hdr *);
324 	if (icmp6len < sizeof(struct icmp6_hdr)) {
325 		icmp6stat.icp6s_tooshort++;
326 		goto freeit;
327 	}
328 
329 	/*
330 	 * calculate the checksum
331 	 */
332 
333 	icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
334 	code = icmp6->icmp6_code;
335 
336 	if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
337 		log(LOG_ERR,
338 		    "ICMP6 checksum error(%d|%x) %s\n",
339 		    icmp6->icmp6_type,
340 		    sum,
341 		    ip6_sprintf(&ip6->ip6_src));
342 		icmp6stat.icp6s_checksum++;
343 		goto freeit;
344 	}
345 
346 #if defined(NFAITH) && 0 < NFAITH
347 	if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
348 		/*
349 		 * Deliver very specific ICMP6 type only.
350 		 * This is important to deilver TOOBIG.  Otherwise PMTUD
351 		 * will not work.
352 		 */
353 		switch (icmp6->icmp6_type) {
354 		case ICMP6_DST_UNREACH:
355 		case ICMP6_PACKET_TOO_BIG:
356 		case ICMP6_TIME_EXCEEDED:
357 			break;
358 		default:
359 			goto freeit;
360 		}
361 	}
362 #endif
363 
364 #ifdef IPSEC
365 	/* drop it if it does not match the default policy */
366 	if (ipsec6_in_reject(m, NULL)) {
367 		ipsecstat.in_polvio++;
368 		goto freeit;
369 	}
370 #endif
371 
372 	icmp6stat.icp6s_inhist[icmp6->icmp6_type]++;
373 
374 	switch (icmp6->icmp6_type) {
375 
376 	case ICMP6_DST_UNREACH:
377 		switch (code) {
378 		case ICMP6_DST_UNREACH_NOROUTE:
379 			code = PRC_UNREACH_NET;
380 			break;
381 		case ICMP6_DST_UNREACH_ADMIN:
382 		case ICMP6_DST_UNREACH_ADDR:
383 			code = PRC_UNREACH_HOST;
384 			break;
385 		case ICMP6_DST_UNREACH_NOTNEIGHBOR:
386 			code = PRC_UNREACH_SRCFAIL;
387 			break;
388 		case ICMP6_DST_UNREACH_NOPORT:
389 			code = PRC_UNREACH_PORT;
390 			break;
391 		default:
392 			goto badcode;
393 		}
394 		goto deliver;
395 		break;
396 
397 	case ICMP6_PACKET_TOO_BIG:
398 		if (code != 0)
399 			goto badcode;
400 	    {
401 		u_int mtu = ntohl(icmp6->icmp6_mtu);
402 		struct rtentry *rt;
403 		struct sockaddr_in6 sin6;
404 #ifdef __bsdi__
405 		struct route_in6 ro6;
406 #endif
407 
408 		code = PRC_MSGSIZE;
409 		bzero(&sin6, sizeof(sin6));
410 		sin6.sin6_family = PF_INET6;
411 		sin6.sin6_len = sizeof(struct sockaddr_in6);
412 		sin6.sin6_addr = ((struct ip6_hdr *)(icmp6 + 1))->ip6_dst;
413 #ifdef __NetBSD__
414 		rt = rtalloc1((struct sockaddr *)&sin6, 1);	/*clone*/
415 		if (!rt || (rt->rt_flags & RTF_HOST) == 0) {
416 			if (rt)
417 				RTFREE(rt);
418 			rt = icmp6_mtudisc_clone((struct sockaddr *)&sin6);
419 		}
420 #endif
421 #ifdef __FreeBSD__
422 		rt = rtalloc1((struct sockaddr *)&sin6, 0,
423 			RTF_CLONING | RTF_PRCLONING);
424 #endif /*__FreeBSD__*/
425 #ifdef __bsdi__
426 		bcopy(&sin6, &ro6.ro_dst, sizeof(struct sockaddr_in6));
427 		ro6.ro_rt = 0;
428 		rtcalloc((struct route *)&ro6);
429 		rt = ro6.ro_rt;
430 #endif /*__bsdi__*/
431 
432 		if (rt && (rt->rt_flags & RTF_HOST)
433 		    && !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
434 			if (mtu < IPV6_MMTU) {
435 				/* xxx */
436 				rt->rt_rmx.rmx_locks |= RTV_MTU;
437 			} else if (mtu < rt->rt_ifp->if_mtu &&
438 				   rt->rt_rmx.rmx_mtu > mtu) {
439 				rt->rt_rmx.rmx_mtu = mtu;
440 			}
441 		}
442 		if (rt)
443 			RTFREE(rt);
444 
445 		goto deliver;
446 	    }
447 		break;
448 
449 	case ICMP6_TIME_EXCEEDED:
450 		switch (code) {
451 		case ICMP6_TIME_EXCEED_TRANSIT:
452 		case ICMP6_TIME_EXCEED_REASSEMBLY:
453 			code += PRC_TIMXCEED_INTRANS;
454 			break;
455 		default:
456 			goto badcode;
457 		}
458 		goto deliver;
459 		break;
460 
461 	case ICMP6_PARAM_PROB:
462 		switch (code) {
463 		case ICMP6_PARAMPROB_NEXTHEADER:
464 			code = PRC_UNREACH_PROTOCOL;
465 			break;
466 		case ICMP6_PARAMPROB_HEADER:
467 		case ICMP6_PARAMPROB_OPTION:
468 			code = PRC_PARAMPROB;
469 			break;
470 		default:
471 			goto badcode;
472 		}
473 		goto deliver;
474 		break;
475 
476 	case ICMP6_ECHO_REQUEST:
477 		if (code != 0)
478 			goto badcode;
479 		if ((n = m_copy(m, 0, M_COPYALL)) == NULL) {
480 			/* Give up remote */
481 			break;
482 		}
483 		if (n->m_flags & M_EXT) {
484 			int gap, move;
485 			struct mbuf *n0 = n;
486 
487 			/*
488 			 * Prepare an internal mbuf. m_pullup() doesn't
489 			 * always copy the length we specified.
490 			 */
491 			MGETHDR(n, M_DONTWAIT, n0->m_type);
492 			if (n == NULL) {
493 				/* Give up remote */
494 				m_freem(n0);
495 				break;
496 			}
497 			M_COPY_PKTHDR(n, n0);
498 			n0->m_flags &= ~M_PKTHDR;
499 			n->m_next = n0;
500 			/*
501 			 * Copy IPv6 and ICMPv6 only.
502 			 */
503 			nip6 = mtod(n, struct ip6_hdr *);
504 			bcopy(ip6, nip6, sizeof(struct ip6_hdr));
505 			nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
506 			bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
507 			/*
508 			 * Adjust mbuf. ip6_plen will be adjusted.
509 			 */
510 			noff = sizeof(struct ip6_hdr);
511 			n->m_len = noff + sizeof(struct icmp6_hdr);
512 			move = off + sizeof(struct icmp6_hdr);
513 			n0->m_len -= move;
514 			n0->m_data += move;
515 			gap = off - noff;
516 			n->m_pkthdr.len -= gap;
517 		} else {
518 			nip6 = mtod(n, struct ip6_hdr *);
519 			nicmp6 = (struct icmp6_hdr *)((caddr_t)nip6 + off);
520 			noff = off;
521 		}
522 		nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
523 		nicmp6->icmp6_code = 0;
524 		if (n) {
525 			icmp6stat.icp6s_reflect++;
526 			icmp6stat.icp6s_outhist[ICMP6_ECHO_REPLY]++;
527 			icmp6_reflect(n, noff);
528 		}
529 		break;
530 
531 	case ICMP6_ECHO_REPLY:
532 		if (code != 0)
533 			goto badcode;
534 		break;
535 
536 	case MLD6_LISTENER_QUERY:
537 	case MLD6_LISTENER_REPORT:
538 		if (icmp6len < sizeof(struct mld6_hdr))
539 			goto badlen;
540 		IP6_EXTHDR_CHECK(m, off, icmp6len, IPPROTO_DONE);
541 		mld6_input(m, off);
542 		/* m stays. */
543 		break;
544 
545 	case MLD6_LISTENER_DONE:
546 		if (icmp6len < sizeof(struct mld6_hdr))
547 			goto badlen;
548 		break;		/* nothing to be done in kernel */
549 
550 	case ICMP6_WRUREQUEST:	/* ICMP6_FQDN_QUERY */
551 	    {
552 		enum { WRU, FQDN } mode;
553 
554 		if (code != 0)
555 			goto badcode;
556 		if (icmp6len == sizeof(struct icmp6_hdr) + 4)
557 			mode = WRU;
558 		else if (icmp6len >= sizeof(struct icmp6_hdr) + 8) /* XXX */
559 			mode = FQDN;
560 		else
561 			goto badlen;
562 
563 #ifdef __FreeBSD__
564 #define hostnamelen	strlen(hostname)
565 #endif
566 		if (mode == FQDN) {
567 			IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_nodeinfo),
568 					 IPPROTO_DONE);
569 			n = ni6_input(m, off);
570 			noff = sizeof(struct ip6_hdr);
571 		}
572 		else {
573 			u_char *p;
574 
575 			MGETHDR(n, M_DONTWAIT, m->m_type);
576 			if (n == NULL) {
577 				/* Give up remote */
578 				break;
579 			}
580 			/*
581 			 * Copy IPv6 and ICMPv6 only.
582 			 */
583 			nip6 = mtod(n, struct ip6_hdr *);
584 			bcopy(ip6, nip6, sizeof(struct ip6_hdr));
585 			nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
586 			bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
587 			p = (u_char *)(nicmp6 + 1);
588 			bzero(p, 4);
589 			bcopy(hostname, p + 4, hostnamelen);
590 			noff = sizeof(struct ip6_hdr);
591 			M_COPY_PKTHDR(n, m); /* just for recvif */
592 			n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
593 				sizeof(struct icmp6_hdr) + 4 + hostnamelen;
594 			nicmp6->icmp6_type = ICMP6_WRUREPLY;
595 			nicmp6->icmp6_code = 0;
596 		}
597 #undef hostnamelen
598 		if (n) {
599 			icmp6stat.icp6s_reflect++;
600 			icmp6stat.icp6s_outhist[ICMP6_WRUREPLY]++;
601 			icmp6_reflect(n, noff);
602 		}
603 		break;
604 	    }
605 
606 	case ICMP6_WRUREPLY:
607 		if (code != 0)
608 			goto badcode;
609 		break;
610 
611 	case ND_ROUTER_SOLICIT:
612 		if (code != 0)
613 			goto badcode;
614 		if (icmp6len < sizeof(struct nd_router_solicit))
615 			goto badlen;
616 		IP6_EXTHDR_CHECK(m, off, icmp6len, IPPROTO_DONE);
617 		nd6_rs_input(m, off, icmp6len);
618 		/* m stays. */
619 		break;
620 
621 	case ND_ROUTER_ADVERT:
622 		if (code != 0)
623 			goto badcode;
624 		if (icmp6len < sizeof(struct nd_router_advert))
625 			goto badlen;
626 		IP6_EXTHDR_CHECK(m, off, icmp6len, IPPROTO_DONE);
627 		nd6_ra_input(m, off, icmp6len);
628 		/* m stays. */
629 		break;
630 
631 	case ND_NEIGHBOR_SOLICIT:
632 		if (code != 0)
633 			goto badcode;
634 		if (icmp6len < sizeof(struct nd_neighbor_solicit))
635 			goto badlen;
636 		IP6_EXTHDR_CHECK(m, off, icmp6len, IPPROTO_DONE);
637 		nd6_ns_input(m, off, icmp6len);
638 		/* m stays. */
639 		break;
640 
641 	case ND_NEIGHBOR_ADVERT:
642 		if (code != 0)
643 			goto badcode;
644 		if (icmp6len < sizeof(struct nd_neighbor_advert))
645 			goto badlen;
646 		IP6_EXTHDR_CHECK(m, off, icmp6len, IPPROTO_DONE);
647 		nd6_na_input(m, off, icmp6len);
648 		/* m stays. */
649 		break;
650 
651 	case ND_REDIRECT:
652 		if (code != 0)
653 			goto badcode;
654 		if (icmp6len < sizeof(struct nd_redirect))
655 			goto badlen;
656 		icmp6_redirect_input(m, off);
657 		/* m stays. */
658 		break;
659 
660 	case ICMP6_ROUTER_RENUMBERING:
661 		if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
662 		    code != ICMP6_ROUTER_RENUMBERING_RESULT)
663 			goto badcode;
664 		if (icmp6len < sizeof(struct icmp6_router_renum))
665 			goto badlen;
666 		break;
667 
668 	default:
669 		printf("icmp6_input: unknown type %d\n", icmp6->icmp6_type);
670 		if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
671 			/* ICMPv6 error: MUST deliver it by spec... */
672 			code = PRC_NCMDS;
673 			/* deliver */
674 		} else {
675 			/* ICMPv6 informational: MUST not deliver */
676 			break;
677 		}
678 	deliver:
679 		if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
680 			icmp6stat.icp6s_tooshort++;
681 			goto freeit;
682 		}
683 		IP6_EXTHDR_CHECK(m, off,
684 			sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr),
685 			IPPROTO_DONE);
686 		icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
687 		bzero(&icmp6src, sizeof(icmp6src));
688 		icmp6src.sin6_len = sizeof(struct sockaddr_in6);
689 		icmp6src.sin6_family = AF_INET6;
690 		icmp6src.sin6_addr = ((struct ip6_hdr *)(icmp6 + 1))->ip6_dst;
691 
692 		/* Detect the upper level protocol */
693 	    {
694 		void (*ctlfunc) __P((int, struct sockaddr *,
695 				     struct ip6_hdr *,
696 				     struct mbuf *, int)); /* XXX */
697 		struct ip6_hdr *eip6 = (struct ip6_hdr *)(icmp6 + 1);
698 		u_int8_t nxt = eip6->ip6_nxt;
699 		int eoff = off + sizeof(struct icmp6_hdr) +
700 			sizeof(struct ip6_hdr);
701 
702 		while (1) { /* XXX: should avoid inf. loop explicitly? */
703 			struct ip6_ext *eh;
704 
705 			switch(nxt) {
706 			case IPPROTO_ESP:
707 			case IPPROTO_NONE:
708 				goto passit;
709 			case IPPROTO_HOPOPTS:
710 			case IPPROTO_DSTOPTS:
711 			case IPPROTO_ROUTING:
712 			case IPPROTO_AH:
713 			case IPPROTO_FRAGMENT:
714 				IP6_EXTHDR_CHECK(m, 0, eoff +
715 						 sizeof(struct ip6_ext),
716 						 IPPROTO_DONE);
717 				eh = (struct ip6_ext *)(mtod(m, caddr_t)
718 							+ eoff);
719 				if (nxt == IPPROTO_AH)
720 					eoff += (eh->ip6e_len + 2) << 2;
721 				else if (nxt == IPPROTO_FRAGMENT)
722 					eoff += sizeof(struct ip6_frag);
723 				else
724 					eoff += (eh->ip6e_len + 1) << 3;
725 				nxt = eh->ip6e_nxt;
726 				break;
727 			default:
728 				goto notify;
729 			}
730 		}
731 	    notify:
732 		icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
733 		ctlfunc = (void (*) __P((int, struct sockaddr *,
734 					 struct ip6_hdr *,
735 					 struct mbuf *, int)))
736 			(inet6sw[ip6_protox[nxt]].pr_ctlinput);
737 		if (ctlfunc)
738 			(*ctlfunc)(code, (struct sockaddr *)&icmp6src,
739 				   (struct ip6_hdr *)(icmp6 + 1),
740 				   m, eoff);
741 	    }
742 		break;
743 
744 	badcode:
745 		icmp6stat.icp6s_badcode++;
746 		break;
747 
748 	badlen:
749 		icmp6stat.icp6s_badlen++;
750 		break;
751 	}
752 
753  passit:
754 	icmp6_rip6_input(&m, *offp);
755 	return IPPROTO_DONE;
756 
757  freeit:
758 	m_freem(m);
759 	return IPPROTO_DONE;
760 }
761 
762 /*
763  * Process a Node Information Query
764  */
765 #ifdef __FreeBSD__
766 #define hostnamelen	strlen(hostname)
767 #endif
768 #ifndef offsetof		/* XXX */
769 #define	offsetof(type, member)	((size_t)(&((type *)0)->member))
770 #endif
771 
772 static struct mbuf *
773 ni6_input(m, off)
774 	struct mbuf *m;
775 	int off;
776 {
777 	struct icmp6_nodeinfo *ni6 =
778 		(struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off), *nni6;
779 	struct mbuf *n = NULL;
780 	u_int16_t qtype = ntohs(ni6->ni_qtype);
781 	int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
782 	struct ni_reply_fqdn *fqdn;
783 	int addrs;		/* for NI_QTYPE_NODEADDR */
784 	struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
785 
786 	switch(qtype) {
787 	 case NI_QTYPE_NOOP:
788 		 break;		/* no reply data */
789 	 case NI_QTYPE_SUPTYPES:
790 		 goto bad;	/* xxx: to be implemented */
791 		 break;
792 	 case NI_QTYPE_FQDN:
793 		 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_name) +
794 			 hostnamelen;
795 		 break;
796 	 case NI_QTYPE_NODEADDR:
797 		 addrs = ni6_addrs(ni6, m, &ifp);
798 		 if ((replylen += addrs * sizeof(struct in6_addr)) > MCLBYTES)
799 			 replylen = MCLBYTES; /* XXX: we'll truncate later */
800 
801 		 break;
802 	 default:
803 		 /*
804 		  * XXX: We must return a reply with the ICMP6 code
805 		  * `unknown Qtype' in this case. However we regard the case
806 		  * as an FQDN query for backward compatibility.
807 		  * Older versions set a random value to this field,
808 		  * so it rarely varies in the defined qtypes.
809 		  * But the mechanism is not reliable...
810 		  * maybe we should obsolete older versions.
811 		  */
812 		 qtype = NI_QTYPE_FQDN;
813 		 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_name) +
814 			 hostnamelen;
815 		 break;
816 	}
817 
818 	/* allocate a mbuf to reply. */
819 	MGETHDR(n, M_DONTWAIT, m->m_type);
820 	if (n == NULL)
821 		return(NULL);
822 	M_COPY_PKTHDR(n, m); /* just for recvif */
823 	if (replylen > MHLEN) {
824 		if (replylen > MCLBYTES)
825 			 /*
826 			  * XXX: should we try to allocate more? But MCLBYTES is
827 			  * probably much larger than IPV6_MMTU...
828 			  */
829 			goto bad;
830 		MCLGET(n, M_DONTWAIT);
831 		if ((n->m_flags & M_EXT) == 0) {
832 			goto bad;
833 		}
834 	}
835 	n->m_pkthdr.len = n->m_len = replylen;
836 
837 	/* copy mbuf header and IPv6 + Node Information base headers */
838 	bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
839 	nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
840 	bcopy(mtod(m, caddr_t) + off, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));
841 
842 	/* qtype dependent procedure */
843 	switch (qtype) {
844 	 case NI_QTYPE_NOOP:
845 		 nni6->ni_flags = 0;
846 		 break;
847 	 case NI_QTYPE_SUPTYPES:
848 		 goto bad;	/* xxx: to be implemented */
849 		 break;
850 	 case NI_QTYPE_FQDN:
851 		 if (hostnamelen > 255) { /* XXX: rare case, but may happen */
852 			 printf("ni6_input: "
853 				"hostname length(%d) is too large for reply\n",
854 				hostnamelen);
855 			 goto bad;
856 		 }
857 		 fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
858 						 sizeof(struct ip6_hdr) +
859 						 sizeof(struct icmp6_nodeinfo));
860 		 nni6->ni_flags = 0; /* XXX: meaningless TTL */
861 		 fqdn->ni_fqdn_ttl = 0;	/* ditto. */
862 		 fqdn->ni_fqdn_namelen = hostnamelen;
863 		 bcopy(hostname, &fqdn->ni_fqdn_name[0], hostnamelen);
864 		 break;
865 	 case NI_QTYPE_NODEADDR:
866 	 {
867 		 int lenlim, copied;
868 
869 		 if (n->m_flags & M_EXT)
870 			 lenlim = MCLBYTES - sizeof(struct ip6_hdr) -
871 				 sizeof(struct icmp6_nodeinfo);
872 		 else
873 			 lenlim = MHLEN - sizeof(struct ip6_hdr) -
874 				 sizeof(struct icmp6_nodeinfo);
875 		 copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
876 		 /* XXX: reset mbuf length */
877 		 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
878 			 sizeof(struct icmp6_nodeinfo) + copied;
879 		 break;
880 	 }
881 	 default:
882 		 break;		/* XXX impossible! */
883 	}
884 
885 	nni6->ni_type = ICMP6_NI_REPLY;
886 	nni6->ni_code = ICMP6_NI_SUCESS;
887 	return(n);
888 
889   bad:
890 	if (n)
891 		m_freem(n);
892 	return(NULL);
893 }
894 #undef hostnamelen
895 
896 /*
897  * calculate the number of addresses to be returned in the node info reply.
898  */
899 static int
900 ni6_addrs(ni6, m, ifpp)
901 	struct icmp6_nodeinfo *ni6;
902 	struct mbuf *m;
903 	struct ifnet **ifpp;
904 {
905 	register struct ifnet *ifp;
906 	register struct in6_ifaddr *ifa6;
907 	register struct ifaddr *ifa;
908 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
909 	int addrs = 0, addrsofif, iffound = 0;
910 
911 #ifdef __NetBSD__
912 	for (ifp = TAILQ_FIRST(&ifnet); ifp; ifp = TAILQ_NEXT(ifp, if_list))
913 #else
914 	for (ifp = ifnet; ifp; ifp = ifp->if_next)
915 #endif
916 	{
917 		addrsofif = 0;
918 #ifdef __NetBSD__
919 		for (ifa = ifp->if_addrlist.tqh_first; ifa;
920 		     ifa = ifa->ifa_list.tqe_next)
921 #else
922 		for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
923 #endif
924 		{
925 			if (ifa->ifa_addr->sa_family != AF_INET6)
926 				continue;
927 			ifa6 = (struct in6_ifaddr *)ifa;
928 
929 			if (!(ni6->ni_flags & NI_NODEADDR_FLAG_ALL) &&
930 			    IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
931 					       &ifa6->ia_addr.sin6_addr))
932 				iffound = 1;
933 
934 			if (ifa6->ia6_flags & IN6_IFF_ANYCAST)
935 				continue; /* we need only unicast addresses */
936 
937 			if ((ni6->ni_flags & (NI_NODEADDR_FLAG_LINKLOCAL |
938 					      NI_NODEADDR_FLAG_SITELOCAL |
939 					      NI_NODEADDR_FLAG_GLOBAL)) == 0)
940 				continue;
941 
942 			/* What do we have to do about ::1? */
943 			switch(in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
944 			 case IPV6_ADDR_SCOPE_LINKLOCAL:
945 				if (ni6->ni_flags & NI_NODEADDR_FLAG_LINKLOCAL)
946 					addrsofif++;
947 				break;
948 			 case IPV6_ADDR_SCOPE_SITELOCAL:
949 				if (ni6->ni_flags & NI_NODEADDR_FLAG_SITELOCAL)
950 					addrsofif++;
951 				break;
952 			 case IPV6_ADDR_SCOPE_GLOBAL:
953 				 if (ni6->ni_flags & NI_NODEADDR_FLAG_GLOBAL)
954 					 addrsofif++;
955 				 break;
956 			 default:
957 				 continue;
958 			}
959 		}
960 		if (iffound) {
961 			*ifpp = ifp;
962 			return(addrsofif);
963 		}
964 
965 		addrs += addrsofif;
966 	}
967 
968 	return(addrs);
969 }
970 
971 static int
972 ni6_store_addrs(ni6, nni6, ifp0, resid)
973 	struct icmp6_nodeinfo *ni6, *nni6;
974 	struct ifnet *ifp0;
975 	int resid;
976 {
977 #ifdef __NetBSD__
978 	register struct ifnet *ifp = ifp0 ? ifp0 : TAILQ_FIRST(&ifnet);
979 #else
980 	register struct ifnet *ifp = ifp0 ? ifp0 : ifnet;
981 #endif
982 	register struct in6_ifaddr *ifa6;
983 	register struct ifaddr *ifa;
984 	int docopy, copied = 0;
985 	u_char *cp = (u_char *)(nni6 + 1);
986 
987 	if (ifp0 == NULL && !(ni6->ni_flags & NI_NODEADDR_FLAG_ALL))
988 		return(0);	/* needless to copy */
989 
990 #ifdef __NetBSD__
991 	for (; ifp; ifp = TAILQ_NEXT(ifp, if_list))
992 #else
993 	for (; ifp; ifp = ifp->if_next)
994 #endif
995 	{
996 #ifdef __NetBSD__
997 		for (ifa = ifp->if_addrlist.tqh_first; ifa;
998 		     ifa = ifa->ifa_list.tqe_next)
999 #else
1000 		for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
1001 #endif
1002 		{
1003 			docopy = 0;
1004 
1005 			if (ifa->ifa_addr->sa_family != AF_INET6)
1006 				continue;
1007 			ifa6 = (struct in6_ifaddr *)ifa;
1008 
1009 			if (ifa6->ia6_flags & IN6_IFF_ANYCAST)
1010 				continue; /* we need only unicast addresses */
1011 
1012 			/* What do we have to do about ::1? */
1013 			switch(in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
1014 			 case IPV6_ADDR_SCOPE_LINKLOCAL:
1015 				if (ni6->ni_flags & NI_NODEADDR_FLAG_LINKLOCAL)
1016 					docopy = 1;
1017 				break;
1018 			 case IPV6_ADDR_SCOPE_SITELOCAL:
1019 				if (ni6->ni_flags & NI_NODEADDR_FLAG_SITELOCAL)
1020 					docopy = 1;
1021 				break;
1022 			 case IPV6_ADDR_SCOPE_GLOBAL:
1023 				 if (ni6->ni_flags & NI_NODEADDR_FLAG_GLOBAL)
1024 					 docopy = 1;
1025 				 break;
1026 			 default:
1027 				 continue;
1028 			}
1029 
1030 			if (docopy) {
1031 				if (resid < sizeof(struct in6_addr)) {
1032 					/*
1033 					 * We give up much more copy.
1034 					 * Set the truncate flag and return.
1035 					 */
1036 					nni6->ni_flags |=
1037 						NI_NODEADDR_FLAG_TRUNCATE;
1038 					return(copied);
1039 				}
1040 				bcopy(&ifa6->ia_addr.sin6_addr, cp,
1041 				      sizeof(struct in6_addr));
1042 				/* XXX: KAME link-local hack; remove ifindex */
1043 				if (IN6_IS_ADDR_LINKLOCAL(&ifa6->ia_addr.sin6_addr))
1044 					((struct in6_addr *)cp)->s6_addr16[1] = 0;
1045 				cp += sizeof(struct in6_addr);
1046 				resid -= sizeof(struct in6_addr);
1047 				copied += sizeof(struct in6_addr);
1048 			}
1049 		}
1050 		if (ifp0)	/* we need search only on the specified IF */
1051 			break;
1052 	}
1053 
1054 	return(copied);
1055 }
1056 
1057 /*
1058  * XXX almost dup'ed code with rip6_input.
1059  */
1060 static int
1061 icmp6_rip6_input(mp, off)
1062 	struct	mbuf **mp;
1063 	int	off;
1064 {
1065 	struct mbuf *m = *mp;
1066 	register struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1067 	register struct in6pcb *in6p;
1068 	struct in6pcb *last = NULL;
1069 	struct sockaddr_in6 rip6src;
1070 	struct icmp6_hdr *icmp6;
1071 	struct mbuf *opts = NULL;
1072 
1073 	/* this is assumed to be safe. */
1074 	icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
1075 
1076 	bzero(&rip6src, sizeof(rip6src));
1077 	rip6src.sin6_len = sizeof(struct sockaddr_in6);
1078 	rip6src.sin6_family = AF_INET6;
1079 	rip6src.sin6_addr = ip6->ip6_src;
1080 	if (IN6_IS_SCOPE_LINKLOCAL(&rip6src.sin6_addr))
1081 		rip6src.sin6_addr.s6_addr16[1] = 0;
1082 	if (m->m_pkthdr.rcvif) {
1083 		if (IN6_IS_SCOPE_LINKLOCAL(&rip6src.sin6_addr))
1084 			rip6src.sin6_scope_id = m->m_pkthdr.rcvif->if_index;
1085 		else
1086 			rip6src.sin6_scope_id = 0;
1087 	} else
1088 		rip6src.sin6_scope_id = 0;
1089 
1090 #if !defined(__FreeBSD__) || __FreeBSD__ < 3
1091 	for (in6p = rawin6pcb.in6p_next;
1092 	     in6p != &rawin6pcb; in6p = in6p->in6p_next)
1093 #else
1094 	LIST_FOREACH(in6p, &ripcb, inp_list)
1095 #endif
1096 	{
1097 #if defined(__FreeBSD__) && __FreeBSD__ >= 3
1098 		if ((in6p->inp_vflag & INP_IPV6) == NULL)
1099 			continue;
1100 #endif
1101 		if (in6p->in6p_ip6_nxt != IPPROTO_ICMPV6)
1102 			continue;
1103 		if (!IN6_IS_ADDR_ANY(&in6p->in6p_laddr) &&
1104 		   !IN6_ARE_ADDR_EQUAL(&in6p->in6p_laddr, &ip6->ip6_dst))
1105 			continue;
1106 		if (!IN6_IS_ADDR_ANY(&in6p->in6p_faddr) &&
1107 		   !IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr, &ip6->ip6_src))
1108 			continue;
1109 		if (in6p->in6p_icmp6filt
1110 		    && ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
1111 				 in6p->in6p_icmp6filt))
1112 			continue;
1113 		if (last) {
1114 			struct	mbuf *n;
1115 			if ((n = m_copy(m, 0, (int)M_COPYALL)) != NULL) {
1116 				if (last->in6p_flags & IN6P_CONTROLOPTS)
1117 					ip6_savecontrol(last, &opts, ip6, n);
1118 				/* strip intermediate headers */
1119 				m_adj(n, off);
1120 				if (sbappendaddr(&last->in6p_socket->so_rcv,
1121 						 (struct sockaddr *)&rip6src,
1122 						 n, opts) == 0) {
1123 					/* should notify about lost packet */
1124 					m_freem(n);
1125 					if (opts)
1126 						m_freem(opts);
1127 				} else
1128 					sorwakeup(last->in6p_socket);
1129 				opts = NULL;
1130 			}
1131 		}
1132 		last = in6p;
1133 	}
1134 	if (last) {
1135 		if (last->in6p_flags & IN6P_CONTROLOPTS)
1136 			ip6_savecontrol(last, &opts, ip6, m);
1137 		/* strip intermediate headers */
1138 		m_adj(m, off);
1139 		if (sbappendaddr(&last->in6p_socket->so_rcv,
1140 				(struct sockaddr *)&rip6src, m, opts) == 0) {
1141 			m_freem(m);
1142 			if (opts)
1143 				m_freem(opts);
1144 		} else
1145 			sorwakeup(last->in6p_socket);
1146 	} else {
1147 		m_freem(m);
1148 		ip6stat.ip6s_delivered--;
1149 	}
1150 	return IPPROTO_DONE;
1151 }
1152 
1153 /*
1154  * Reflect the ip6 packet back to the source.
1155  * The caller MUST check if the destination is multicast or not.
1156  * This function is usually called with a unicast destination which
1157  * can be safely the source of the reply packet. But some exceptions
1158  * exist(e.g. ECHOREPLY, PATCKET_TOOBIG, "10" in OPTION type).
1159  * ``off'' points to the icmp6 header, counted from the top of the mbuf.
1160  */
1161 void
1162 icmp6_reflect(m, off)
1163 	struct	mbuf *m;
1164 	size_t off;
1165 {
1166 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1167 	struct icmp6_hdr *icmp6;
1168 	struct in6_ifaddr *ia;
1169 	struct in6_addr t, *src = 0;
1170 	int plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
1171 #ifdef COMPAT_RFC1885
1172 	int mtu = IPV6_MMTU;
1173 	struct sockaddr_in6 *sin6 = &icmp6_reflect_rt.ro_dst;
1174 #endif
1175 
1176 	/*
1177 	 * If there are extra headers between IPv6 and ICMPv6, strip
1178 	 * off that header first.
1179 	 */
1180 	if (off != sizeof(struct ip6_hdr)) {
1181 		size_t siz;
1182 
1183 		/* sanity checks */
1184 		if (off < sizeof(struct ip6_hdr)) {
1185 			printf("sanity fail: off=%x, sizeof(ip6)=%x in %s:%d\n",
1186 			       (unsigned int)off,
1187 			       (unsigned int)sizeof(struct ip6_hdr),
1188 			       __FILE__, __LINE__);
1189 			goto bad;
1190 		}
1191 		siz = off - sizeof(struct ip6_hdr);
1192 		if (plen < siz) {
1193 			printf("sanity fail: siz=%x, payloadlen=%x in %s:%d\n",
1194 			       (unsigned int)siz, plen, __FILE__, __LINE__);
1195 			goto bad;
1196 		}
1197 		IP6_EXTHDR_CHECK(m, 0, off, /*nothing*/);
1198 		IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_hdr), /*nothing*/);
1199 
1200 		bcopy((caddr_t)ip6,
1201 			(caddr_t)(mtod(m, u_char *) + siz),
1202 			sizeof(struct ip6_hdr));
1203 		m->m_data += siz;
1204 		m->m_len -= siz;
1205 		m->m_pkthdr.len -= siz;
1206 		ip6 = mtod(m, struct ip6_hdr *);
1207 		ip6->ip6_nxt = IPPROTO_ICMPV6;
1208 		plen -= siz;
1209 	}
1210 
1211 	icmp6 = (struct icmp6_hdr *)(ip6 + 1);
1212 
1213 	t = ip6->ip6_dst;
1214 	/*
1215 	 * ip6_input() drops a packet if its src is multicast.
1216 	 * So, the src is never multicast.
1217 	 */
1218 	ip6->ip6_dst = ip6->ip6_src;
1219 
1220 	/* XXX hack for link-local addresses */
1221 	if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
1222 		ip6->ip6_dst.s6_addr16[1] =
1223 			htons(m->m_pkthdr.rcvif->if_index);
1224 	if (IN6_IS_ADDR_LINKLOCAL(&t))
1225 		t.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
1226 
1227 #ifdef COMPAT_RFC1885
1228 	/*
1229 	 * xxx guess MTU
1230 	 * RFC 1885 requires that echo reply should be truncated if it
1231 	 * does not fit in with (return) path MTU, but the description was
1232 	 * removed in the new spec.
1233 	 */
1234 	if (icmp6_reflect_rt.ro_rt == 0 ||
1235 	    ! (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr, &ip6->ip6_dst))) {
1236 		if (icmp6_reflect_rt.ro_rt) {
1237 #ifdef __FreeBSD__
1238 			RTFREE(icmp6_reflect_rt.ro_rt);
1239 #endif
1240 #ifdef __bsdi__
1241 			rtfree(icmp6_reflect_rt.ro_rt);
1242 #endif
1243 			icmp6_reflect_rt.ro_rt = 0;
1244 		}
1245 		bzero(sin6, sizeof(*sin6));
1246 		sin6->sin6_family = PF_INET6;
1247 		sin6->sin6_len = sizeof(struct sockaddr_in6);
1248 		sin6->sin6_addr = ip6->ip6_dst;
1249 
1250 #ifdef __FreeBSD__
1251 		rtalloc_ign((struct route *)&icmp6_reflect_rt.ro_rt,
1252 			    RTF_PRCLONING);
1253 #else
1254 		rtalloc((struct route *)&icmp6_reflect_rt.ro_rt);
1255 #endif
1256 	}
1257 
1258 	if (icmp6_reflect_rt.ro_rt == 0)
1259 		goto bad;
1260 
1261 	if ((icmp6_reflect_rt.ro_rt->rt_flags & RTF_HOST)
1262 	    && mtu < icmp6_reflect_rt.ro_rt->rt_ifp->if_mtu)
1263 		mtu = icmp6_reflect_rt.ro_rt->rt_rmx.rmx_mtu;
1264 
1265 	if (mtu < m->m_pkthdr.len) {
1266 		plen -= (m->m_pkthdr.len - mtu);
1267 		m_adj(m, mtu - m->m_pkthdr.len);
1268 	}
1269 #endif
1270 	/*
1271 	 * If the incoming packet was addressed directly to us(i.e. unicast),
1272 	 * use dst as the src for the reply.
1273 	 */
1274 	for (ia = in6_ifaddr; ia; ia = ia->ia_next)
1275 		if (IN6_ARE_ADDR_EQUAL(&t, &ia->ia_addr.sin6_addr) &&
1276 		    (ia->ia6_flags & IN6_IFF_ANYCAST) == 0) {
1277 			src = &t;
1278 			break;
1279 		}
1280 	if (ia == NULL && IN6_IS_ADDR_LINKLOCAL(&t) && (m->m_flags & M_LOOP)) {
1281 		/*
1282 		 * This is the case if the dst is our link-local address
1283 		 * and the sender is also ourseleves.
1284 		 */
1285 		src = &t;
1286 	}
1287 
1288 	if (src == 0)
1289 		/*
1290 		 * We have not multicast routing yet. So this case matches
1291 		 * to our multicast, our anycast or not to our unicast.
1292 		 * Select a source address which has the same scope.
1293 		 */
1294 		if ((ia = in6_ifawithscope(m->m_pkthdr.rcvif, &t)) != 0)
1295 			src = &IA6_SIN6(ia)->sin6_addr;
1296 
1297 	if (src == 0)
1298 		goto bad;
1299 
1300 	ip6->ip6_src = *src;
1301 
1302 	ip6->ip6_flow = 0;
1303 	ip6->ip6_vfc = IPV6_VERSION;
1304 	ip6->ip6_nxt = IPPROTO_ICMPV6;
1305 	if (m->m_pkthdr.rcvif) {
1306 		/* XXX: This may not be the outgoing interface */
1307 		ip6->ip6_hlim = nd_ifinfo[m->m_pkthdr.rcvif->if_index].chlim;
1308 	}
1309 
1310 	icmp6->icmp6_cksum = 0;
1311 	icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
1312 					sizeof(struct ip6_hdr), plen);
1313 
1314 	/*
1315 	 * xxx option handling
1316 	 */
1317 
1318 	m->m_flags &= ~(M_BCAST|M_MCAST);
1319 #ifdef IPSEC
1320 	m->m_pkthdr.rcvif = NULL;
1321 #endif /*IPSEC*/
1322 
1323 #ifdef COMPAT_RFC1885
1324 	ip6_output(m, NULL, &icmp6_reflect_rt, 0, NULL);
1325 #else
1326 	ip6_output(m, NULL, NULL, 0, NULL);
1327 #endif
1328 
1329 	return;
1330 
1331  bad:
1332 	m_freem(m);
1333 	return;
1334 }
1335 
1336 void
1337 icmp6_fasttimo()
1338 {
1339 	mld6_fasttimeo();
1340 }
1341 
1342 static void
1343 icmp6_redirect_diag(level, src6, dst6, tgt6)
1344 	int level;
1345 	struct in6_addr *src6;
1346 	struct in6_addr *dst6;
1347 	struct in6_addr *tgt6;
1348 {
1349 	log(level, "ICMP6 redirect: src=%s dst=%s tgt=%s\n",
1350 		ip6_sprintf(src6), ip6_sprintf(dst6), ip6_sprintf(tgt6));
1351 }
1352 
1353 void
1354 icmp6_redirect_input(m, off)
1355 	register struct mbuf *m;
1356 	int off;
1357 {
1358 	struct ifnet *ifp = m->m_pkthdr.rcvif;
1359 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
1360 	struct nd_redirect *nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
1361 	int icmp6len = ntohs(ip6->ip6_plen);
1362 	char *lladdr = NULL;
1363 	int lladdrlen = 0;
1364 	u_char *redirhdr = NULL;
1365 	int redirhdrlen = 0;
1366 	struct rtentry *rt = NULL;
1367 	int is_router;
1368 	int is_onlink;
1369 	struct in6_addr src6 = ip6->ip6_src;
1370 	struct in6_addr redtgt6 = nd_rd->nd_rd_target;
1371 	struct in6_addr reddst6 = nd_rd->nd_rd_dst;
1372 	union nd_opts ndopts;
1373 
1374 	if (!m || !ifp)
1375 		return;
1376 
1377 	/* XXX if we are router, we don't update route by icmp6 redirect */
1378 	if (ip6_forwarding)
1379 		return;
1380 	if (!icmp6_rediraccept)
1381 		return;
1382 
1383 	if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
1384 		redtgt6.s6_addr16[1] = htons(ifp->if_index);
1385 	if (IN6_IS_ADDR_LINKLOCAL(&reddst6))
1386 		reddst6.s6_addr16[1] = htons(ifp->if_index);
1387 
1388 	/* validation */
1389 	if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
1390 		log(LOG_ERR,
1391 			"ICMP6 redirect sent from %s rejected; "
1392 			"must be from linklocal\n", ip6_sprintf(&src6));
1393 		return;
1394 	}
1395 	if (ip6->ip6_hlim != 255) {
1396 		log(LOG_ERR,
1397 			"ICMP6 redirect sent from %s rejected; "
1398 			"hlim=%d (must be 255)\n",
1399 			ip6_sprintf(&src6), ip6->ip6_hlim);
1400 		return;
1401 	}
1402     {
1403 	/* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
1404 	struct sockaddr_in6 sin6;
1405 	struct in6_addr *gw6;
1406 
1407 	bzero(&sin6, sizeof(sin6));
1408 	sin6.sin6_family = AF_INET6;
1409 	sin6.sin6_len = sizeof(struct sockaddr_in6);
1410 	bcopy(&reddst6, &sin6.sin6_addr, sizeof(reddst6));
1411 	rt = rtalloc1((struct sockaddr *)&sin6, 0
1412 #ifdef __FreeBSD__
1413 		      , 0UL
1414 #endif
1415 		      );
1416 	if (rt) {
1417 		gw6 = &(((struct sockaddr_in6 *)rt->rt_gateway)->sin6_addr);
1418 		if (bcmp(&src6, gw6, sizeof(struct in6_addr)) != 0) {
1419 			icmp6_redirect_diag(LOG_ERR, &src6, &reddst6, &redtgt6);
1420 			log(LOG_ERR,
1421 				"ICMP6 redirect sent from %s rejected; "
1422 				"not equal to gw for src=%s (must be same)\n",
1423 				ip6_sprintf(&src6), ip6_sprintf(gw6));
1424 			RTFREE(rt);
1425 			return;
1426 		}
1427 	} else {
1428 		icmp6_redirect_diag(LOG_ERR, &src6, &reddst6, &redtgt6);
1429 		log(LOG_ERR,
1430 			"ICMP6 redirect sent from %s rejected; "
1431 			"no route found for redirect dst\n",
1432 			ip6_sprintf(&src6));
1433 		return;
1434 	}
1435 	RTFREE(rt);
1436 	rt = NULL;
1437     }
1438 	if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
1439 		icmp6_redirect_diag(LOG_ERR, &src6, &reddst6, &redtgt6);
1440 		log(LOG_ERR,
1441 			"ICMP6 redirect sent from %s rejected; "
1442 			"redirect dst must be unicast\n",
1443 			ip6_sprintf(&src6));
1444 		return;
1445 	}
1446 
1447 	is_router = is_onlink = 0;
1448 	if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
1449 		is_router = 1;	/* router case */
1450 	if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
1451 		is_onlink = 1;	/* on-link destination case */
1452 	if (!is_router && !is_onlink) {
1453 		icmp6_redirect_diag(LOG_ERR, &src6, &reddst6, &redtgt6);
1454 		log(LOG_ERR,
1455 			"ICMP6 redirect sent from %s rejected; "
1456 			"neither router case nor onlink case\n",
1457 			ip6_sprintf(&src6));
1458 		return;
1459 	}
1460 	/* validation passed */
1461 
1462 	icmp6len -= sizeof(*nd_rd);
1463 	nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
1464 	if (nd6_options(&ndopts) < 0) {
1465 		icmp6_redirect_diag(LOG_INFO, &src6, &reddst6, &redtgt6);
1466 		log(LOG_INFO, "icmp6_redirect_input: "
1467 			"invalid ND option, rejected\n");
1468 		return;
1469 	}
1470 
1471 	if (ndopts.nd_opts_tgt_lladdr) {
1472 		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
1473 		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
1474 	}
1475 
1476 	if (ndopts.nd_opts_rh) {
1477 		redirhdrlen = ndopts.nd_opts_rh->nd_opt_rh_len;
1478 		redirhdr = (u_char *)(ndopts.nd_opts_rh + 1); /* xxx */
1479 	}
1480 
1481 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
1482 		icmp6_redirect_diag(LOG_INFO, &src6, &reddst6, &redtgt6);
1483 		log(LOG_INFO,
1484 			"icmp6_redirect_input: lladdrlen mismatch for %s "
1485 			"(if %d, icmp6 packet %d)\n",
1486 			ip6_sprintf(&redtgt6), ifp->if_addrlen, lladdrlen - 2);
1487 	}
1488 
1489 	/* RFC 2461 8.3 */
1490 	nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
1491 			 is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
1492 
1493 	if (!is_onlink) {	/* better router case. perform rtredirect. */
1494 		/* perform rtredirect */
1495 		struct sockaddr_in6 sdst;
1496 		struct sockaddr_in6 sgw;
1497 		struct sockaddr_in6 ssrc;
1498 #ifdef __bsdi__
1499 		extern int icmp_redirtimeout;	/*XXX*/
1500 #endif
1501 
1502 		bzero(&sdst, sizeof(sdst));
1503 		bzero(&sgw, sizeof(sgw));
1504 		bzero(&ssrc, sizeof(ssrc));
1505 		sdst.sin6_family = sgw.sin6_family = ssrc.sin6_family = AF_INET6;
1506 		sdst.sin6_len = sgw.sin6_len = ssrc.sin6_len =
1507 			sizeof(struct sockaddr_in6);
1508 		bcopy(&redtgt6, &sgw.sin6_addr, sizeof(struct in6_addr));
1509 		bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
1510 		bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
1511 		rtredirect((struct sockaddr *)&sdst, (struct sockaddr *)&sgw,
1512 			   (struct sockaddr *)NULL, RTF_GATEWAY | RTF_HOST,
1513 			   (struct sockaddr *)&ssrc,
1514 #if defined(__FreeBSD__) || defined(__NetBSD__)
1515 			   (struct rtentry **)NULL
1516 #elif defined(__bsdi__)
1517 			   icmp_redirtimeout /*XXX*/
1518 #endif /*__FreeBSD__, __NetBSD__, __bsdi__*/
1519 			   );
1520 	}
1521 	/* finally update cached route in each socket via pfctlinput */
1522 	{
1523 		struct sockaddr_in6 sdst;
1524 
1525 		bzero(&sdst, sizeof(sdst));
1526 		sdst.sin6_family = AF_INET6;
1527 		sdst.sin6_len = sizeof(struct sockaddr_in6);
1528 		bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
1529 		pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&sdst);
1530 #ifdef IPSEC
1531 		key_sa_routechange((struct sockaddr *)&sdst);
1532 #endif
1533 	}
1534 }
1535 
1536 void
1537 icmp6_redirect_output(m0, rt)
1538 	struct mbuf *m0;
1539 	struct rtentry *rt;
1540 {
1541 	struct ifnet *ifp;	/* my outgoing interface */
1542 	struct in6_addr *ifp_ll6;
1543 	struct in6_addr *router_ll6;
1544 	struct ip6_hdr *sip6;	/* m0 as struct ip6_hdr */
1545 	struct mbuf *m = NULL;	/* newly allocated one */
1546 	struct ip6_hdr *ip6;	/* m as struct ip6_hdr */
1547 	struct nd_redirect *nd_rd;
1548 	size_t maxlen;
1549 	u_char *p;
1550 
1551 	/* if we are not router, we don't send icmp6 redirect */
1552 	if (!ip6_forwarding || ip6_accept_rtadv)
1553 		goto fail;
1554 
1555 	/* sanity check */
1556 	if (!m0 || !rt || !(rt->rt_flags & RTF_UP) || !(ifp = rt->rt_ifp))
1557 		goto fail;
1558 
1559 	/*
1560 	 * Address check:
1561 	 *  the source address must identify a neighbor, and
1562 	 *  the destination address must not be a multicast address
1563 	 *  [RFC 2461, sec 8.2]
1564 	 */
1565 	sip6 = mtod(m0, struct ip6_hdr *);
1566 	if (nd6_is_addr_neighbor(&sip6->ip6_src, ifp) == 0)
1567 		goto fail;
1568 	if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
1569 		goto fail;	/* what should we do here? */
1570 
1571 	/* rate limit */
1572 	if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
1573 		goto fail;
1574 
1575 	/*
1576 	 * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
1577 	 * we almost always ask for an mbuf cluster for simplicity.
1578 	 * (MHLEN < IPV6_MMTU is almost always true)
1579 	 */
1580 	MGETHDR(m, M_DONTWAIT, MT_HEADER);
1581 	if (!m)
1582 		goto fail;
1583 	if (MHLEN < IPV6_MMTU)
1584 		MCLGET(m, M_DONTWAIT);
1585 	maxlen = (m->m_flags & M_EXT) ? MCLBYTES : MHLEN;
1586 	maxlen = min(IPV6_MMTU, maxlen);
1587 	/* just for safety */
1588 	if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr))
1589 		goto fail;
1590 
1591 	{
1592 		/* get ip6 linklocal address for ifp(my outgoing interface). */
1593 		struct in6_ifaddr *ia = in6ifa_ifpforlinklocal(ifp);
1594 		if (ia == NULL)
1595 			goto fail;
1596 		ifp_ll6 = &ia->ia_addr.sin6_addr;
1597 	}
1598 
1599 	/* get ip6 linklocal address for the router. */
1600 	if (rt->rt_gateway && (rt->rt_flags & RTF_GATEWAY)) {
1601 		struct sockaddr_in6 *sin6;
1602 		sin6 = (struct sockaddr_in6 *)rt->rt_gateway;
1603 		router_ll6 = &sin6->sin6_addr;
1604 		if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
1605 			router_ll6 = (struct in6_addr *)NULL;
1606 	} else
1607 		router_ll6 = (struct in6_addr *)NULL;
1608 
1609 	/* ip6 */
1610 	ip6 = mtod(m, struct ip6_hdr *);
1611 	ip6->ip6_flow = 0;
1612 	ip6->ip6_vfc = IPV6_VERSION;
1613 	/* ip6->ip6_plen will be set later */
1614 	ip6->ip6_nxt = IPPROTO_ICMPV6;
1615 	ip6->ip6_hlim = 255;
1616 	/* ip6->ip6_src must be linklocal addr for my outgoing if. */
1617 	bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
1618 	bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));
1619 
1620 	/* ND Redirect */
1621 	nd_rd = (struct nd_redirect *)(ip6 + 1);
1622 	nd_rd->nd_rd_type = ND_REDIRECT;
1623 	nd_rd->nd_rd_code = 0;
1624 	nd_rd->nd_rd_reserved = 0;
1625 	if (rt->rt_flags & RTF_GATEWAY) {
1626 		/*
1627 		 * nd_rd->nd_rd_target must be a link-local address in
1628 		 * better router cases.
1629 		 */
1630 		if (!router_ll6)
1631 			goto fail;
1632 		bcopy(router_ll6, &nd_rd->nd_rd_target,
1633 		      sizeof(nd_rd->nd_rd_target));
1634 		bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
1635 		      sizeof(nd_rd->nd_rd_dst));
1636 	} else {
1637 		/* make sure redtgt == reddst */
1638 		bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
1639 		      sizeof(nd_rd->nd_rd_target));
1640 		bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
1641 		      sizeof(nd_rd->nd_rd_dst));
1642 	}
1643 
1644 	p = (u_char *)(nd_rd + 1);
1645 
1646 	if (!router_ll6)
1647 		goto nolladdropt;
1648 
1649     {
1650 	/* target lladdr option */
1651 	struct rtentry *rt_router = NULL;
1652 	int len;
1653 	struct sockaddr_dl *sdl;
1654 	struct nd_opt_hdr *nd_opt;
1655 	char *lladdr;
1656 
1657 	rt_router = nd6_lookup(router_ll6, 0, ifp);
1658 	if (!rt_router)
1659 		goto nolladdropt;
1660 	if (!(rt_router->rt_flags & RTF_GATEWAY)
1661 	 && (rt_router->rt_flags & RTF_LLINFO)
1662 	 && (rt_router->rt_gateway->sa_family == AF_LINK)
1663 	 && (sdl = (struct sockaddr_dl *)rt_router->rt_gateway)) {
1664 		nd_opt = (struct nd_opt_hdr *)p;
1665 		nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
1666 		len = 2 + ifp->if_addrlen;
1667 		len = (len + 7) & ~7;	/*round by 8*/
1668 		nd_opt->nd_opt_len = len >> 3;
1669 		p += len;
1670 		lladdr = (char *)(nd_opt + 1);
1671 		bcopy(LLADDR(sdl), lladdr, ifp->if_addrlen);
1672 	}
1673     }
1674 nolladdropt:;
1675 
1676 	m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
1677 
1678 	/* just to be safe */
1679 	if (m0->m_flags & M_DECRYPTED)
1680 		goto noredhdropt;
1681 
1682     {
1683 	/* redirected header option */
1684 	int len;
1685 	struct nd_opt_rd_hdr *nd_opt_rh;
1686 
1687 	/*
1688 	 * compute the maximum size for icmp6 redirect header option.
1689 	 * XXX room for auth header?
1690 	 */
1691 	len = maxlen - (p - (u_char *)ip6);
1692 	len &= ~7;
1693 
1694 	/* This is just for simplicity. */
1695 	if (m0->m_pkthdr.len != m0->m_len) {
1696 		if (m0->m_next) {
1697 			m_freem(m0->m_next);
1698 			m0->m_next = NULL;
1699 		}
1700 		m0->m_pkthdr.len = m0->m_len;
1701 	}
1702 
1703 	/*
1704 	 * Redirected header option spec (RFC2461 4.6.3) talks nothing
1705 	 * about padding/trancate rule for the original IP packet.
1706 	 * From the discussion on IPv6imp in Feb 1999, the consensus was:
1707 	 * - "attach as much as possible" is the goal
1708 	 * - pad if not aligned (original size can be guessed by original
1709 	 *   ip6 header)
1710 	 * Following code adds the padding if it is simple enough,
1711 	 * and truncates if not.
1712 	 */
1713 	if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
1714 		panic("assumption failed in %s:%d\n", __FILE__, __LINE__);
1715 
1716 	if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
1717 		/* not enough room, truncate */
1718 		m0->m_pkthdr.len = m0->m_len = len - sizeof(*nd_opt_rh);
1719 	} else {
1720 		/* enough room, pad or truncate */
1721 		size_t extra;
1722 
1723 		extra = m0->m_pkthdr.len % 8;
1724 		if (extra) {
1725 			/* pad if easy enough, truncate if not */
1726 			if (8 - extra <= M_TRAILINGSPACE(m0)) {
1727 				/* pad */
1728 				m0->m_len += (8 - extra);
1729 				m0->m_pkthdr.len += (8 - extra);
1730 			} else {
1731 				/* truncate */
1732 				m0->m_pkthdr.len -= extra;
1733 				m0->m_len -= extra;
1734 			}
1735 		}
1736 		len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
1737 		m0->m_pkthdr.len = m0->m_len = len - sizeof(*nd_opt_rh);
1738 	}
1739 
1740 	nd_opt_rh = (struct nd_opt_rd_hdr *)p;
1741 	bzero(nd_opt_rh, sizeof(*nd_opt_rh));
1742 	nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
1743 	nd_opt_rh->nd_opt_rh_len = len >> 3;
1744 	p += sizeof(*nd_opt_rh);
1745 	m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
1746 
1747 	/* connect m0 to m */
1748 	m->m_next = m0;
1749 	m->m_pkthdr.len = m->m_len + m0->m_len;
1750     }
1751 noredhdropt:;
1752 
1753 	if (IN6_IS_ADDR_LINKLOCAL(&sip6->ip6_src))
1754 		sip6->ip6_src.s6_addr16[1] = 0;
1755 	if (IN6_IS_ADDR_LINKLOCAL(&sip6->ip6_dst))
1756 		sip6->ip6_dst.s6_addr16[1] = 0;
1757 #if 0
1758 	if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
1759 		ip6->ip6_src.s6_addr16[1] = 0;
1760 	if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
1761 		ip6->ip6_dst.s6_addr16[1] = 0;
1762 #endif
1763 	if (IN6_IS_ADDR_LINKLOCAL(&nd_rd->nd_rd_target))
1764 		nd_rd->nd_rd_target.s6_addr16[1] = 0;
1765 	if (IN6_IS_ADDR_LINKLOCAL(&nd_rd->nd_rd_dst))
1766 		nd_rd->nd_rd_dst.s6_addr16[1] = 0;
1767 
1768 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
1769 
1770 	nd_rd->nd_rd_cksum = 0;
1771 	nd_rd->nd_rd_cksum
1772 		= in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), ntohs(ip6->ip6_plen));
1773 
1774 	/* send the packet to outside... */
1775 #ifdef IPSEC
1776 	m->m_pkthdr.rcvif = NULL;
1777 #endif /*IPSEC*/
1778 	ip6_output(m, NULL, NULL, 0, NULL);
1779 	icmp6stat.icp6s_outhist[ND_REDIRECT]++;
1780 
1781 	return;
1782 
1783 fail:
1784 	if (m)
1785 		m_freem(m);
1786 	if (m0)
1787 		m_freem(m0);
1788 }
1789 
1790 /*
1791  * ICMPv6 socket option processing.
1792  */
1793 int
1794 icmp6_ctloutput(op, so, level, optname, mp)
1795 	int op;
1796 	struct socket *so;
1797 	int level, optname;
1798 	struct mbuf **mp;
1799 {
1800 	register struct in6pcb *in6p = sotoin6pcb(so);
1801 	register struct mbuf *m = *mp;
1802 	int error = 0;
1803 
1804 	if (level != IPPROTO_ICMPV6) {
1805 		error = EINVAL;
1806 		if (op == PRCO_SETOPT && m)
1807 			(void)m_free(m);
1808 	} else switch(op) {
1809 	 case PRCO_SETOPT:
1810 		 switch (optname) {
1811 		  case ICMP6_FILTER:
1812 		  {
1813 			  struct icmp6_filter *p;
1814 
1815 			  p = mtod(m, struct icmp6_filter *);
1816 			  if (!p || !in6p->in6p_icmp6filt) {
1817 				  error = EINVAL;
1818 				  break;
1819 			  }
1820 			  bcopy(p, in6p->in6p_icmp6filt,
1821 				sizeof(struct icmp6_filter));
1822 			  error = 0;
1823 			  break;
1824 		  }
1825 
1826 		  default:
1827 			  error = ENOPROTOOPT;
1828 			  break;
1829 		 }
1830 		 if (m)
1831 			 (void)m_free(m);
1832 		 break;
1833 
1834 	 case PRCO_GETOPT:
1835 		 switch (optname) {
1836 		  case ICMP6_FILTER:
1837 		  {
1838 			  struct icmp6_filter *p;
1839 
1840 			  p = mtod(m, struct icmp6_filter *);
1841 			  if (!p || !in6p->in6p_icmp6filt) {
1842 				  error = EINVAL;
1843 				  break;
1844 			  }
1845 			  bcopy(in6p->in6p_icmp6filt, p,
1846 				sizeof(struct icmp6_filter));
1847 			  error = 0;
1848 			  break;
1849 		  }
1850 
1851 		  default:
1852 			  error = ENOPROTOOPT;
1853 			  break;
1854 		 }
1855 		 break;
1856 	}
1857 
1858 	return(error);
1859 }
1860 
1861 /*
1862  * Perform rate limit check.
1863  * Returns 0 if it is okay to send the icmp6 packet.
1864  * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
1865  * limitation.
1866  *
1867  * XXX per-destination/type check necessary?
1868  */
1869 static int
1870 icmp6_ratelimit(dst, type, code)
1871 	const struct in6_addr *dst;	/* not used at this moment */
1872 	const int type;			/* not used at this moment */
1873 	const int code;			/* not used at this moment */
1874 {
1875 	struct timeval tp;
1876 	long sec_diff, usec_diff;
1877 
1878 	/* If we are not doing rate limitation, it is always okay to send */
1879 	if (!icmp6errratelim)
1880 		return 0;
1881 
1882 #if defined(__FreeBSD__) && __FreeBSD__ >= 3
1883 	microtime(&tp);
1884 	tp.tv_sec = time_second;
1885 #else
1886 	tp = time;
1887 #endif
1888 	if (tp.tv_sec < icmp6_nextsend.tv_sec
1889 	 || (tp.tv_sec == icmp6_nextsend.tv_sec
1890 	  && tp.tv_usec < icmp6_nextsend.tv_usec)) {
1891 		/* The packet is subject to rate limit */
1892 		return 1;
1893 	}
1894 	sec_diff = icmp6errratelim / 1000000;
1895 	usec_diff = icmp6errratelim % 1000000;
1896 	icmp6_nextsend.tv_sec = tp.tv_sec + sec_diff;
1897 	if ((tp.tv_usec = tp.tv_usec + usec_diff) >= 1000000) {
1898 		icmp6_nextsend.tv_sec++;
1899 		icmp6_nextsend.tv_usec -= 1000000;
1900 	}
1901 
1902 	/* it is okay to send this */
1903 	return 0;
1904 }
1905 
1906 #ifdef __NetBSD__
1907 static struct rtentry *
1908 icmp6_mtudisc_clone(dst)
1909 	struct sockaddr *dst;
1910 {
1911 	struct rtentry *rt;
1912 	int    error;
1913 
1914 	rt = rtalloc1(dst, 1);
1915 	if (rt == 0)
1916 		return NULL;
1917 
1918 	/* If we didn't get a host route, allocate one */
1919 	if ((rt->rt_flags & RTF_HOST) == 0) {
1920 		struct rtentry *nrt;
1921 
1922 		error = rtrequest((int) RTM_ADD, dst,
1923 		    (struct sockaddr *) rt->rt_gateway,
1924 		    (struct sockaddr *) 0,
1925 		    RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt);
1926 		if (error) {
1927 			rtfree(rt);
1928 			rtfree(nrt);
1929 			return NULL;
1930 		}
1931 		nrt->rt_rmx = rt->rt_rmx;
1932 		rtfree(rt);
1933 		rt = nrt;
1934 	}
1935 	error = rt_timer_add(rt, icmp6_mtudisc_timeout,
1936 			icmp6_mtudisc_timeout_q);
1937 	if (error) {
1938 		rtfree(rt);
1939 		return NULL;
1940 	}
1941 
1942 	return rt;	/* caller need to call rtfree() */
1943 }
1944 
1945 static void
1946 icmp6_mtudisc_timeout(rt, r)
1947 	struct rtentry *rt;
1948 	struct rttimer *r;
1949 {
1950 	if (rt == NULL)
1951 		panic("icmp6_mtudisc_timeout: bad route to timeout");
1952 	if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) ==
1953 	    (RTF_DYNAMIC | RTF_HOST)) {
1954 		rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
1955 		    rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
1956 	} else {
1957 		if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) {
1958 			rt->rt_rmx.rmx_mtu = 0;
1959 		}
1960 	}
1961 }
1962 #endif /*__NetBSD__*/
1963 
1964 #ifdef __bsdi__
1965 void
1966 icmp6_mtuexpire(rt, rtt)
1967 	struct rtentry *rt;
1968 	struct rttimer *rtt;
1969 {
1970 	rt->rt_flags |= RTF_PROBEMTU;
1971 	Free(rtt);
1972 }
1973 
1974 int *icmp6_sysvars[] = ICMPV6CTL_VARS;
1975 
1976 int
1977 icmp6_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
1978 	int *name;
1979 	u_int namelen;
1980 	void *oldp;
1981 	size_t *oldlenp;
1982 	void *newp;
1983 	size_t newlen;
1984 {
1985 	if (name[0] >= ICMPV6CTL_MAXID)
1986 		return (EOPNOTSUPP);
1987 	switch (name[0]) {
1988 #if 0
1989 	ICMPV6CTL_ND6_PRUNE:
1990 	ICMPV6CTL_ND6_DELAY:
1991 	ICMPV6CTL_ND6_UMAXTRIES:
1992 	ICMPV6CTL_ND6_MMAXTRIES:
1993 	ICMPV6CTL_ND6_USELOOPBACK:
1994 	ICMPV6CTL_ND6_PROXYALL:
1995 		/* need to check the value. */
1996 #endif
1997 	case ICMPV6CTL_STATS:
1998 		return sysctl_rdtrunc(oldp, oldlenp, newp, &icmp6stat,
1999 		    sizeof(icmp6stat));
2000 
2001 	default:
2002 		return (sysctl_int_arr(icmp6_sysvars, name, namelen,
2003 		    oldp, oldlenp, newp, newlen));
2004 	}
2005 }
2006 #endif /*__bsdi__*/
2007 
2008 #ifdef __NetBSD__
2009 #include <vm/vm.h>
2010 #include <sys/sysctl.h>
2011 int
2012 icmp6_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
2013 	int *name;
2014 	u_int namelen;
2015 	void *oldp;
2016 	size_t *oldlenp;
2017 	void *newp;
2018 	size_t newlen;
2019 {
2020 
2021 	/* All sysctl names at this level are terminal. */
2022 	if (namelen != 1)
2023 		return ENOTDIR;
2024 
2025 	switch (name[0]) {
2026 
2027 	case ICMPV6CTL_REDIRACCEPT:
2028 		return sysctl_int(oldp, oldlenp, newp, newlen,
2029 				&icmp6_rediraccept);
2030 	case ICMPV6CTL_REDIRTIMEOUT:
2031 		return sysctl_int(oldp, oldlenp, newp, newlen,
2032 				&icmp6_redirtimeout);
2033 	case ICMPV6CTL_STATS:
2034 		return sysctl_rdstruct(oldp, oldlenp, newp,
2035 				&icmp6stat, sizeof(icmp6stat));
2036 	case ICMPV6CTL_ERRRATELIMIT:
2037 		return sysctl_int(oldp, oldlenp, newp, newlen,
2038 				  &icmp6errratelim);
2039 	case ICMPV6CTL_ND6_PRUNE:
2040 		return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_prune);
2041 	case ICMPV6CTL_ND6_DELAY:
2042 		return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_delay);
2043 	case ICMPV6CTL_ND6_UMAXTRIES:
2044 		return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_umaxtries);
2045 	case ICMPV6CTL_ND6_MMAXTRIES:
2046 		return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_mmaxtries);
2047 	case ICMPV6CTL_ND6_USELOOPBACK:
2048 		return sysctl_int(oldp, oldlenp, newp, newlen,
2049 				&nd6_useloopback);
2050 	case ICMPV6CTL_ND6_PROXYALL:
2051 		return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_proxyall);
2052 	default:
2053 		return ENOPROTOOPT;
2054 	}
2055 	/* NOTREACHED */
2056 }
2057 #endif /* __NetBSD__ */
2058