xref: /dragonfly/sys/netinet6/nd6_nbr.c (revision acea3a2a)
1 /*	$FreeBSD: src/sys/netinet6/nd6_nbr.c,v 1.4.2.6 2003/01/23 21:06:47 sam Exp $	*/
2 /*	$DragonFly: src/sys/netinet6/nd6_nbr.c,v 1.11 2005/02/12 02:56:05 joerg Exp $	*/
3 /*	$KAME: nd6_nbr.c,v 1.86 2002/01/21 02:33:04 jinmei Exp $	*/
4 
5 /*
6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the project nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include "opt_inet.h"
35 #include "opt_inet6.h"
36 #include "opt_ipsec.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/malloc.h>
41 #include <sys/mbuf.h>
42 #include <sys/socket.h>
43 #include <sys/sockio.h>
44 #include <sys/time.h>
45 #include <sys/kernel.h>
46 #include <sys/errno.h>
47 #include <sys/syslog.h>
48 #include <sys/queue.h>
49 #include <sys/callout.h>
50 
51 #include <net/if.h>
52 #include <net/if_types.h>
53 #include <net/if_dl.h>
54 #include <net/route.h>
55 
56 #include <netinet/in.h>
57 #include <netinet/in_var.h>
58 #include <netinet6/in6_var.h>
59 #include <netinet/ip6.h>
60 #include <netinet6/ip6_var.h>
61 #include <netinet6/nd6.h>
62 #include <netinet/icmp6.h>
63 
64 #ifdef IPSEC
65 #include <netinet6/ipsec.h>
66 #ifdef INET6
67 #include <netinet6/ipsec6.h>
68 #endif
69 #endif
70 
71 #include <net/net_osdep.h>
72 
73 #define SDL(s) ((struct sockaddr_dl *)s)
74 
75 struct dadq;
76 static struct dadq *nd6_dad_find (struct ifaddr *);
77 static void nd6_dad_starttimer (struct dadq *, int);
78 static void nd6_dad_stoptimer (struct dadq *);
79 static void nd6_dad_timer (struct ifaddr *);
80 static void nd6_dad_ns_output (struct dadq *, struct ifaddr *);
81 static void nd6_dad_ns_input (struct ifaddr *);
82 static void nd6_dad_na_input (struct ifaddr *);
83 
84 static int dad_ignore_ns = 0;	/* ignore NS in DAD - specwise incorrect*/
85 static int dad_maxtry = 15;	/* max # of *tries* to transmit DAD packet */
86 
87 /*
88  * Input an Neighbor Solicitation Message.
89  *
90  * Based on RFC 2461
91  * Based on RFC 2462 (duplicated address detection)
92  */
93 void
94 nd6_ns_input(struct mbuf *m, int off, int icmp6len)
95 {
96 	struct ifnet *ifp = m->m_pkthdr.rcvif;
97 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
98 	struct nd_neighbor_solicit *nd_ns;
99 	struct in6_addr saddr6 = ip6->ip6_src;
100 	struct in6_addr daddr6 = ip6->ip6_dst;
101 	struct in6_addr taddr6;
102 	struct in6_addr myaddr6;
103 	char *lladdr = NULL;
104 	struct ifaddr *ifa;
105 	int lladdrlen = 0;
106 	int anycast = 0, proxy = 0, tentative = 0;
107 	int tlladdr;
108 	union nd_opts ndopts;
109 	struct sockaddr_dl *proxydl = NULL;
110 
111 #ifndef PULLDOWN_TEST
112 	IP6_EXTHDR_CHECK(m, off, icmp6len,);
113 	nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
114 #else
115 	IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
116 	if (nd_ns == NULL) {
117 		icmp6stat.icp6s_tooshort++;
118 		return;
119 	}
120 #endif
121 	ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
122 	taddr6 = nd_ns->nd_ns_target;
123 
124 	if (ip6->ip6_hlim != 255) {
125 		nd6log((LOG_ERR,
126 		    "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
127 		    ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
128 		    ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
129 		goto bad;
130 	}
131 
132 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
133 		/* dst has to be solicited node multicast address. */
134 		if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL
135 		    /* don't check ifindex portion */
136 		    && daddr6.s6_addr32[1] == 0
137 		    && daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE
138 		    && daddr6.s6_addr8[12] == 0xff) {
139 			; /* good */
140 		} else {
141 			nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
142 				"(wrong ip6 dst)\n"));
143 			goto bad;
144 		}
145 	}
146 
147 	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
148 		nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
149 		goto bad;
150 	}
151 
152 	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
153 		taddr6.s6_addr16[1] = htons(ifp->if_index);
154 
155 	icmp6len -= sizeof(*nd_ns);
156 	nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
157 	if (nd6_options(&ndopts) < 0) {
158 		nd6log((LOG_INFO,
159 		    "nd6_ns_input: invalid ND option, ignored\n"));
160 		/* nd6_options have incremented stats */
161 		goto freeit;
162 	}
163 
164 	if (ndopts.nd_opts_src_lladdr) {
165 		lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
166 		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
167 	}
168 
169 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
170 		nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
171 		    "(link-layer address option)\n"));
172 		goto bad;
173 	}
174 
175 	/*
176 	 * Attaching target link-layer address to the NA?
177 	 * (RFC 2461 7.2.4)
178 	 *
179 	 * NS IP dst is unicast/anycast			MUST NOT add
180 	 * NS IP dst is solicited-node multicast	MUST add
181 	 *
182 	 * In implementation, we add target link-layer address by default.
183 	 * We do not add one in MUST NOT cases.
184 	 */
185 #if 0 /* too much! */
186 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6);
187 	if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST))
188 		tlladdr = 0;
189 	else
190 #endif
191 	if (!IN6_IS_ADDR_MULTICAST(&daddr6))
192 		tlladdr = 0;
193 	else
194 		tlladdr = 1;
195 
196 	/*
197 	 * Target address (taddr6) must be either:
198 	 * (1) Valid unicast/anycast address for my receiving interface,
199 	 * (2) Unicast address for which I'm offering proxy service, or
200 	 * (3) "tentative" address on which DAD is being performed.
201 	 */
202 	/* (1) and (3) check. */
203 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
204 
205 	/* (2) check. */
206 	if (!ifa) {
207 		struct rtentry *rt;
208 		struct sockaddr_in6 tsin6;
209 
210 		bzero(&tsin6, sizeof tsin6);
211 		tsin6.sin6_len = sizeof(struct sockaddr_in6);
212 		tsin6.sin6_family = AF_INET6;
213 		tsin6.sin6_addr = taddr6;
214 
215 		rt = rtpurelookup((struct sockaddr *)&tsin6);
216 		if (rt != NULL && (rt->rt_flags & RTF_ANNOUNCE) &&
217 		    rt->rt_gateway->sa_family == AF_LINK) {
218 			/*
219 			 * proxy NDP for single entry
220 			 */
221 			ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
222 				IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
223 			if (ifa) {
224 				proxy = 1;
225 				proxydl = SDL(rt->rt_gateway);
226 			}
227 		}
228 		if (rt != NULL)
229 			--rt->rt_refcnt;
230 	}
231 	if (ifa == NULL) {
232 		/*
233 		 * We've got an NS packet, and we don't have that adddress
234 		 * assigned for us.  We MUST silently ignore it.
235 		 * See RFC2461 7.2.3.
236 		 */
237 		goto freeit;
238 	}
239 	myaddr6 = *IFA_IN6(ifa);
240 	anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
241 	tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
242 	if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
243 		goto freeit;
244 
245 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
246 		nd6log((LOG_INFO,
247 		    "nd6_ns_input: lladdrlen mismatch for %s "
248 		    "(if %d, NS packet %d)\n",
249 			ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2));
250 		goto bad;
251 	}
252 
253 	if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
254 		nd6log((LOG_INFO,
255 			"nd6_ns_input: duplicate IP6 address %s\n",
256 			ip6_sprintf(&saddr6)));
257 		goto freeit;
258 	}
259 
260 	/*
261 	 * We have neighbor solicitation packet, with target address equals to
262 	 * one of my tentative address.
263 	 *
264 	 * src addr	how to process?
265 	 * ---		---
266 	 * multicast	of course, invalid (rejected in ip6_input)
267 	 * unicast	somebody is doing address resolution -> ignore
268 	 * unspec	dup address detection
269 	 *
270 	 * The processing is defined in RFC 2462.
271 	 */
272 	if (tentative) {
273 		/*
274 		 * If source address is unspecified address, it is for
275 		 * duplicated address detection.
276 		 *
277 		 * If not, the packet is for addess resolution;
278 		 * silently ignore it.
279 		 */
280 		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
281 			nd6_dad_ns_input(ifa);
282 
283 		goto freeit;
284 	}
285 
286 	/*
287 	 * If the source address is unspecified address, entries must not
288 	 * be created or updated.
289 	 * It looks that sender is performing DAD.  Output NA toward
290 	 * all-node multicast address, to tell the sender that I'm using
291 	 * the address.
292 	 * S bit ("solicited") must be zero.
293 	 */
294 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
295 		saddr6 = in6addr_linklocal_allnodes;
296 		saddr6.s6_addr16[1] = htons(ifp->if_index);
297 		nd6_na_output(ifp, &saddr6, &taddr6,
298 			      ((anycast || proxy || !tlladdr)
299 				      ? 0 : ND_NA_FLAG_OVERRIDE)
300 			      	| (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
301 			      tlladdr, (struct sockaddr *)proxydl);
302 		goto freeit;
303 	}
304 
305 	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0);
306 
307 	nd6_na_output(ifp, &saddr6, &taddr6,
308 		      ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE)
309 			| (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0)
310 			| ND_NA_FLAG_SOLICITED,
311 		      tlladdr, (struct sockaddr *)proxydl);
312  freeit:
313 	m_freem(m);
314 	return;
315 
316  bad:
317 	nd6log((LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6)));
318 	nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6)));
319 	nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6)));
320 	icmp6stat.icp6s_badns++;
321 	m_freem(m);
322 }
323 
324 /*
325  * Output an Neighbor Solicitation Message. Caller specifies:
326  *	- ICMP6 header source IP6 address
327  *	- ND6 header target IP6 address
328  *	- ND6 header source datalink address
329  *
330  * Based on RFC 2461
331  * Based on RFC 2462 (duplicated address detection)
332  */
333 void
334 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *daddr6,
335 	      const struct in6_addr *taddr6,
336 	      struct llinfo_nd6 *ln,	/* for source address determination */
337 	      int dad)			/* duplicated address detection */
338 {
339 	struct mbuf *m;
340 	struct ip6_hdr *ip6;
341 	struct nd_neighbor_solicit *nd_ns;
342 	struct in6_ifaddr *ia = NULL;
343 	struct ip6_moptions im6o;
344 	int icmp6len;
345 	int maxlen;
346 	caddr_t mac;
347 	struct ifnet *outif = NULL;
348 
349 	if (IN6_IS_ADDR_MULTICAST(taddr6))
350 		return;
351 
352 	/* estimate the size of message */
353 	maxlen = sizeof(*ip6) + sizeof(*nd_ns);
354 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
355 	if (max_linkhdr + maxlen >= MCLBYTES) {
356 #ifdef DIAGNOSTIC
357 		printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
358 		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
359 #endif
360 		return;
361 	}
362 
363 	MGETHDR(m, MB_DONTWAIT, MT_DATA);
364 	if (m && max_linkhdr + maxlen >= MHLEN) {
365 		MCLGET(m, MB_DONTWAIT);
366 		if ((m->m_flags & M_EXT) == 0) {
367 			m_free(m);
368 			m = NULL;
369 		}
370 	}
371 	if (m == NULL)
372 		return;
373 	m->m_pkthdr.rcvif = NULL;
374 
375 	if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
376 		m->m_flags |= M_MCAST;
377 		im6o.im6o_multicast_ifp = ifp;
378 		im6o.im6o_multicast_hlim = 255;
379 		im6o.im6o_multicast_loop = 0;
380 	}
381 
382 	icmp6len = sizeof(*nd_ns);
383 	m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
384 	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */
385 
386 	/* fill neighbor solicitation packet */
387 	ip6 = mtod(m, struct ip6_hdr *);
388 	ip6->ip6_flow = 0;
389 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
390 	ip6->ip6_vfc |= IPV6_VERSION;
391 	/* ip6->ip6_plen will be set later */
392 	ip6->ip6_nxt = IPPROTO_ICMPV6;
393 	ip6->ip6_hlim = 255;
394 	if (daddr6)
395 		ip6->ip6_dst = *daddr6;
396 	else {
397 		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
398 		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
399 		ip6->ip6_dst.s6_addr32[1] = 0;
400 		ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
401 		ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
402 		ip6->ip6_dst.s6_addr8[12] = 0xff;
403 	}
404 	if (!dad) {
405 #if 0	/* KAME way, exact address scope match */
406 		/*
407 		 * Select a source whose scope is the same as that of the dest.
408 		 * Typically, the dest is link-local solicitation multicast
409 		 * (i.e. neighbor discovery) or link-local/global unicast
410 		 * (i.e. neighbor un-reachability detection).
411 		 */
412 		ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
413 		if (ia == NULL) {
414 			m_freem(m);
415 			return;
416 		}
417 		ip6->ip6_src = ia->ia_addr.sin6_addr;
418 #else	/* spec-wise correct */
419 		/*
420 		 * RFC2461 7.2.2:
421 		 * "If the source address of the packet prompting the
422 		 * solicitation is the same as one of the addresses assigned
423 		 * to the outgoing interface, that address SHOULD be placed
424 		 * in the IP Source Address of the outgoing solicitation.
425 		 * Otherwise, any one of the addresses assigned to the
426 		 * interface should be used."
427 		 *
428 		 * We use the source address for the prompting packet
429 		 * (saddr6), if:
430 		 * - saddr6 is given from the caller (by giving "ln"), and
431 		 * - saddr6 belongs to the outgoing interface.
432 		 * Otherwise, we perform a scope-wise match.
433 		 */
434 		struct ip6_hdr *hip6;		/* hold ip6 */
435 		struct in6_addr *saddr6;
436 
437 		if (ln && ln->ln_hold) {
438 			hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
439 			/* XXX pullup? */
440 			if (sizeof(*hip6) < ln->ln_hold->m_len)
441 				saddr6 = &hip6->ip6_src;
442 			else
443 				saddr6 = NULL;
444 		} else
445 			saddr6 = NULL;
446 		if (saddr6 && in6ifa_ifpwithaddr(ifp, saddr6))
447 			bcopy(saddr6, &ip6->ip6_src, sizeof(*saddr6));
448 		else {
449 			ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
450 			if (ia == NULL) {
451 				m_freem(m);
452 				return;
453 			}
454 			ip6->ip6_src = ia->ia_addr.sin6_addr;
455 		}
456 #endif
457 	} else {
458 		/*
459 		 * Source address for DAD packet must always be IPv6
460 		 * unspecified address. (0::0)
461 		 */
462 		bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
463 	}
464 	nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
465 	nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
466 	nd_ns->nd_ns_code = 0;
467 	nd_ns->nd_ns_reserved = 0;
468 	nd_ns->nd_ns_target = *taddr6;
469 
470 	if (IN6_IS_SCOPE_LINKLOCAL(&nd_ns->nd_ns_target))
471 		nd_ns->nd_ns_target.s6_addr16[1] = 0;
472 
473 	/*
474 	 * Add source link-layer address option.
475 	 *
476 	 *				spec		implementation
477 	 *				---		---
478 	 * DAD packet			MUST NOT	do not add the option
479 	 * there's no link layer address:
480 	 *				impossible	do not add the option
481 	 * there's link layer address:
482 	 *	Multicast NS		MUST add one	add the option
483 	 *	Unicast NS		SHOULD add one	add the option
484 	 */
485 	if (!dad && (mac = nd6_ifptomac(ifp))) {
486 		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
487 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
488 		/* 8 byte alignments... */
489 		optlen = (optlen + 7) & ~7;
490 
491 		m->m_pkthdr.len += optlen;
492 		m->m_len += optlen;
493 		icmp6len += optlen;
494 		bzero((caddr_t)nd_opt, optlen);
495 		nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
496 		nd_opt->nd_opt_len = optlen >> 3;
497 		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
498 	}
499 
500 	ip6->ip6_plen = htons((u_short)icmp6len);
501 	nd_ns->nd_ns_cksum = 0;
502 	nd_ns->nd_ns_cksum
503 		= in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
504 
505 	ip6_output(m, NULL, NULL, dad ? IPV6_DADOUTPUT : 0, &im6o, &outif, NULL);
506 	if (outif) {
507 		icmp6_ifstat_inc(outif, ifs6_out_msg);
508 		icmp6_ifstat_inc(outif, ifs6_out_neighborsolicit);
509 	}
510 	icmp6stat.icp6s_outhist[ND_NEIGHBOR_SOLICIT]++;
511 }
512 
513 /*
514  * Neighbor advertisement input handling.
515  *
516  * Based on RFC 2461
517  * Based on RFC 2462 (duplicated address detection)
518  *
519  * the following items are not implemented yet:
520  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
521  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
522  */
523 void
524 nd6_na_input(struct mbuf *m, int off, int icmp6len)
525 {
526 	struct ifnet *ifp = m->m_pkthdr.rcvif;
527 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
528 	struct nd_neighbor_advert *nd_na;
529 #if 0
530 	struct in6_addr saddr6 = ip6->ip6_src;
531 #endif
532 	struct in6_addr daddr6 = ip6->ip6_dst;
533 	struct in6_addr taddr6;
534 	int flags;
535 	int is_router;
536 	int is_solicited;
537 	int is_override;
538 	char *lladdr = NULL;
539 	int lladdrlen = 0;
540 	struct ifaddr *ifa;
541 	struct llinfo_nd6 *ln;
542 	struct rtentry *rt;
543 	struct sockaddr_dl *sdl;
544 	union nd_opts ndopts;
545 
546 	if (ip6->ip6_hlim != 255) {
547 		nd6log((LOG_ERR,
548 		    "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
549 		    ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
550 		    ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
551 		goto bad;
552 	}
553 
554 #ifndef PULLDOWN_TEST
555 	IP6_EXTHDR_CHECK(m, off, icmp6len,);
556 	nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
557 #else
558 	IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
559 	if (nd_na == NULL) {
560 		icmp6stat.icp6s_tooshort++;
561 		return;
562 	}
563 #endif
564 	taddr6 = nd_na->nd_na_target;
565 	flags = nd_na->nd_na_flags_reserved;
566 	is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
567 	is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
568 	is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
569 
570 	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
571 		taddr6.s6_addr16[1] = htons(ifp->if_index);
572 
573 	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
574 		nd6log((LOG_ERR,
575 		    "nd6_na_input: invalid target address %s\n",
576 		    ip6_sprintf(&taddr6)));
577 		goto bad;
578 	}
579 	if (IN6_IS_ADDR_MULTICAST(&daddr6))
580 		if (is_solicited) {
581 			nd6log((LOG_ERR,
582 			    "nd6_na_input: a solicited adv is multicasted\n"));
583 			goto bad;
584 		}
585 
586 	icmp6len -= sizeof(*nd_na);
587 	nd6_option_init(nd_na + 1, icmp6len, &ndopts);
588 	if (nd6_options(&ndopts) < 0) {
589 		nd6log((LOG_INFO,
590 		    "nd6_na_input: invalid ND option, ignored\n"));
591 		/* nd6_options have incremented stats */
592 		goto freeit;
593 	}
594 
595 	if (ndopts.nd_opts_tgt_lladdr) {
596 		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
597 		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
598 	}
599 
600 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
601 
602 	/*
603 	 * Target address matches one of my interface address.
604 	 *
605 	 * If my address is tentative, this means that there's somebody
606 	 * already using the same address as mine.  This indicates DAD failure.
607 	 * This is defined in RFC 2462.
608 	 *
609 	 * Otherwise, process as defined in RFC 2461.
610 	 */
611 	if (ifa
612 	 && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
613 		nd6_dad_na_input(ifa);
614 		goto freeit;
615 	}
616 
617 	/* Just for safety, maybe unnecessary. */
618 	if (ifa) {
619 		log(LOG_ERR,
620 		    "nd6_na_input: duplicate IP6 address %s\n",
621 		    ip6_sprintf(&taddr6));
622 		goto freeit;
623 	}
624 
625 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
626 		nd6log((LOG_INFO,
627 		    "nd6_na_input: lladdrlen mismatch for %s "
628 		    "(if %d, NA packet %d)\n",
629 			ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2));
630 		goto bad;
631 	}
632 
633 	/*
634 	 * If no neighbor cache entry is found, NA SHOULD silently be discarded.
635 	 */
636 	rt = nd6_lookup(&taddr6, 0, ifp);
637 	if ((rt == NULL) ||
638 	   ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) ||
639 	   ((sdl = SDL(rt->rt_gateway)) == NULL))
640 		goto freeit;
641 
642 	if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
643 		/*
644 		 * If the link-layer has address, and no lladdr option came,
645 		 * discard the packet.
646 		 */
647 		if (ifp->if_addrlen && !lladdr)
648 			goto freeit;
649 
650 		/*
651 		 * Record link-layer address, and update the state.
652 		 */
653 		sdl->sdl_alen = ifp->if_addrlen;
654 		bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
655 		if (is_solicited) {
656 			ln->ln_state = ND6_LLINFO_REACHABLE;
657 			ln->ln_byhint = 0;
658 			if (ln->ln_expire)
659 				ln->ln_expire = time_second +
660 				    ND_IFINFO(rt->rt_ifp)->reachable;
661 		} else {
662 			ln->ln_state = ND6_LLINFO_STALE;
663 			ln->ln_expire = time_second + nd6_gctimer;
664 		}
665 		if ((ln->ln_router = is_router) != 0) {
666 			/*
667 			 * This means a router's state has changed from
668 			 * non-reachable to probably reachable, and might
669 			 * affect the status of associated prefixes..
670 			 */
671 			pfxlist_onlink_check();
672 		}
673 	} else {
674 		int llchange;
675 
676 		/*
677 		 * Check if the link-layer address has changed or not.
678 		 */
679 		if (!lladdr)
680 			llchange = 0;
681 		else {
682 			if (sdl->sdl_alen) {
683 				if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen))
684 					llchange = 1;
685 				else
686 					llchange = 0;
687 			} else
688 				llchange = 1;
689 		}
690 
691 		/*
692 		 * This is VERY complex.  Look at it with care.
693 		 *
694 		 * override solicit lladdr llchange	action
695 		 *					(L: record lladdr)
696 		 *
697 		 *	0	0	n	--	(2c)
698 		 *	0	0	y	n	(2b) L
699 		 *	0	0	y	y	(1)    REACHABLE->STALE
700 		 *	0	1	n	--	(2c)   *->REACHABLE
701 		 *	0	1	y	n	(2b) L *->REACHABLE
702 		 *	0	1	y	y	(1)    REACHABLE->STALE
703 		 *	1	0	n	--	(2a)
704 		 *	1	0	y	n	(2a) L
705 		 *	1	0	y	y	(2a) L *->STALE
706 		 *	1	1	n	--	(2a)   *->REACHABLE
707 		 *	1	1	y	n	(2a) L *->REACHABLE
708 		 *	1	1	y	y	(2a) L *->REACHABLE
709 		 */
710 		if (!is_override && (lladdr && llchange)) {	   /* (1) */
711 			/*
712 			 * If state is REACHABLE, make it STALE.
713 			 * no other updates should be done.
714 			 */
715 			if (ln->ln_state == ND6_LLINFO_REACHABLE) {
716 				ln->ln_state = ND6_LLINFO_STALE;
717 				ln->ln_expire = time_second + nd6_gctimer;
718 			}
719 			goto freeit;
720 		} else if (is_override				   /* (2a) */
721 			|| (!is_override && (lladdr && !llchange)) /* (2b) */
722 			|| !lladdr) {				   /* (2c) */
723 			/*
724 			 * Update link-local address, if any.
725 			 */
726 			if (lladdr) {
727 				sdl->sdl_alen = ifp->if_addrlen;
728 				bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
729 			}
730 
731 			/*
732 			 * If solicited, make the state REACHABLE.
733 			 * If not solicited and the link-layer address was
734 			 * changed, make it STALE.
735 			 */
736 			if (is_solicited) {
737 				ln->ln_state = ND6_LLINFO_REACHABLE;
738 				ln->ln_byhint = 0;
739 				if (ln->ln_expire) {
740 					ln->ln_expire = time_second +
741 					    ND_IFINFO(ifp)->reachable;
742 				}
743 			} else {
744 				if (lladdr && llchange) {
745 					ln->ln_state = ND6_LLINFO_STALE;
746 					ln->ln_expire = time_second + nd6_gctimer;
747 				}
748 			}
749 		}
750 
751 		if (ln->ln_router && !is_router) {
752 			/*
753 			 * The peer dropped the router flag.
754 			 * Remove the sender from the Default Router List and
755 			 * update the Destination Cache entries.
756 			 */
757 			struct nd_defrouter *dr;
758 			struct in6_addr *in6;
759 			int s;
760 
761 			in6 = &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr;
762 
763 			/*
764 			 * Lock to protect the default router list.
765 			 * XXX: this might be unnecessary, since this function
766 			 * is only called under the network software interrupt
767 			 * context.  However, we keep it just for safety.
768 			 */
769 			s = splnet();
770 			dr = defrouter_lookup(in6, rt->rt_ifp);
771 			if (dr)
772 				defrtrlist_del(dr);
773 			else if (!ip6_forwarding && ip6_accept_rtadv) {
774 				/*
775 				 * Even if the neighbor is not in the default
776 				 * router list, the neighbor may be used
777 				 * as a next hop for some destinations
778 				 * (e.g. redirect case). So we must
779 				 * call rt6_flush explicitly.
780 				 */
781 				rt6_flush(&ip6->ip6_src, rt->rt_ifp);
782 			}
783 			splx(s);
784 		}
785 		ln->ln_router = is_router;
786 	}
787 	rt->rt_flags &= ~RTF_REJECT;
788 	ln->ln_asked = 0;
789 	if (ln->ln_hold) {
790 		/*
791 		 * we assume ifp is not a loopback here, so just set the 2nd
792 		 * argument as the 1st one.
793 		 */
794 		nd6_output(ifp, ifp, ln->ln_hold,
795 			   (struct sockaddr_in6 *)rt_key(rt), rt);
796 		ln->ln_hold = 0;
797 	}
798 
799  freeit:
800 	m_freem(m);
801 	return;
802 
803  bad:
804 	icmp6stat.icp6s_badna++;
805 	m_freem(m);
806 }
807 
808 /*
809  * Neighbor advertisement output handling.
810  *
811  * Based on RFC 2461
812  *
813  * the following items are not implemented yet:
814  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
815  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
816  */
817 void
818 nd6_na_output(struct ifnet *ifp, const struct in6_addr *daddr6,
819 	      const struct in6_addr *taddr6, u_long flags,
820 	      int tlladdr,	/* 1 if include target link-layer address */
821 	      struct sockaddr *sdl0)	/* sockaddr_dl (= proxy NA) or NULL */
822 {
823 	struct mbuf *m;
824 	struct ip6_hdr *ip6;
825 	struct nd_neighbor_advert *nd_na;
826 	struct in6_ifaddr *ia = NULL;
827 	struct ip6_moptions im6o;
828 	int icmp6len;
829 	int maxlen;
830 	caddr_t mac;
831 	struct ifnet *outif = NULL;
832 
833 	/* estimate the size of message */
834 	maxlen = sizeof(*ip6) + sizeof(*nd_na);
835 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
836 	if (max_linkhdr + maxlen >= MCLBYTES) {
837 #ifdef DIAGNOSTIC
838 		printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
839 		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
840 #endif
841 		return;
842 	}
843 
844 	MGETHDR(m, MB_DONTWAIT, MT_DATA);
845 	if (m && max_linkhdr + maxlen >= MHLEN) {
846 		MCLGET(m, MB_DONTWAIT);
847 		if ((m->m_flags & M_EXT) == 0) {
848 			m_free(m);
849 			m = NULL;
850 		}
851 	}
852 	if (m == NULL)
853 		return;
854 	m->m_pkthdr.rcvif = NULL;
855 
856 	if (IN6_IS_ADDR_MULTICAST(daddr6)) {
857 		m->m_flags |= M_MCAST;
858 		im6o.im6o_multicast_ifp = ifp;
859 		im6o.im6o_multicast_hlim = 255;
860 		im6o.im6o_multicast_loop = 0;
861 	}
862 
863 	icmp6len = sizeof(*nd_na);
864 	m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
865 	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */
866 
867 	/* fill neighbor advertisement packet */
868 	ip6 = mtod(m, struct ip6_hdr *);
869 	ip6->ip6_flow = 0;
870 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
871 	ip6->ip6_vfc |= IPV6_VERSION;
872 	ip6->ip6_nxt = IPPROTO_ICMPV6;
873 	ip6->ip6_hlim = 255;
874 	if (IN6_IS_ADDR_UNSPECIFIED(daddr6)) {
875 		/* reply to DAD */
876 		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
877 		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
878 		ip6->ip6_dst.s6_addr32[1] = 0;
879 		ip6->ip6_dst.s6_addr32[2] = 0;
880 		ip6->ip6_dst.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
881 		flags &= ~ND_NA_FLAG_SOLICITED;
882 	} else
883 		ip6->ip6_dst = *daddr6;
884 
885 	/*
886 	 * Select a source whose scope is the same as that of the dest.
887 	 */
888 	ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
889 	if (ia == NULL) {
890 		m_freem(m);
891 		return;
892 	}
893 	ip6->ip6_src = ia->ia_addr.sin6_addr;
894 	nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
895 	nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
896 	nd_na->nd_na_code = 0;
897 	nd_na->nd_na_target = *taddr6;
898 	if (IN6_IS_SCOPE_LINKLOCAL(&nd_na->nd_na_target))
899 		nd_na->nd_na_target.s6_addr16[1] = 0;
900 
901 	/*
902 	 * "tlladdr" indicates NS's condition for adding tlladdr or not.
903 	 * see nd6_ns_input() for details.
904 	 * Basically, if NS packet is sent to unicast/anycast addr,
905 	 * target lladdr option SHOULD NOT be included.
906 	 */
907 	mac = NULL;
908 	if (tlladdr) {
909 		/*
910 		 * sdl0 != NULL indicates proxy NA.  If we do proxy, use
911 		 * lladdr in sdl0.  If we are not proxying (sending NA for
912 		 * my address) use lladdr configured for the interface.
913 		 */
914 		if (sdl0 == NULL)
915 			mac = nd6_ifptomac(ifp);
916 		else if (sdl0->sa_family == AF_LINK) {
917 			struct sockaddr_dl *sdl;
918 			sdl = (struct sockaddr_dl *)sdl0;
919 			if (sdl->sdl_alen == ifp->if_addrlen)
920 				mac = LLADDR(sdl);
921 		}
922 	}
923 	if (mac != NULL) {
924 		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
925 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
926 
927 		/* roundup to 8 bytes alignment! */
928 		optlen = (optlen + 7) & ~7;
929 
930 		m->m_pkthdr.len += optlen;
931 		m->m_len += optlen;
932 		icmp6len += optlen;
933 		bzero((caddr_t)nd_opt, optlen);
934 		nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
935 		nd_opt->nd_opt_len = optlen >> 3;
936 		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
937 	} else
938 		flags &= ~ND_NA_FLAG_OVERRIDE;
939 
940 	ip6->ip6_plen = htons((u_short)icmp6len);
941 	nd_na->nd_na_flags_reserved = flags;
942 	nd_na->nd_na_cksum = 0;
943 	nd_na->nd_na_cksum =
944 		in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
945 
946 	ip6_output(m, NULL, NULL, 0, &im6o, &outif, NULL);
947 	if (outif) {
948 		icmp6_ifstat_inc(outif, ifs6_out_msg);
949 		icmp6_ifstat_inc(outif, ifs6_out_neighboradvert);
950 	}
951 	icmp6stat.icp6s_outhist[ND_NEIGHBOR_ADVERT]++;
952 }
953 
954 caddr_t
955 nd6_ifptomac(struct ifnet *ifp)
956 {
957 	switch (ifp->if_type) {
958 	case IFT_ARCNET:
959 	case IFT_ETHER:
960 	case IFT_FDDI:
961 	case IFT_IEEE1394:
962 #ifdef IFT_L2VLAN
963 	case IFT_L2VLAN:
964 #endif
965 #ifdef IFT_IEEE80211
966 	case IFT_IEEE80211:
967 #endif
968 		return ((caddr_t)(ifp + 1));
969 		break;
970 	default:
971 		return NULL;
972 	}
973 }
974 
975 TAILQ_HEAD(dadq_head, dadq);
976 struct dadq {
977 	TAILQ_ENTRY(dadq) dad_list;
978 	struct ifaddr *dad_ifa;
979 	int dad_count;		/* max NS to send */
980 	int dad_ns_tcount;	/* # of trials to send NS */
981 	int dad_ns_ocount;	/* NS sent so far */
982 	int dad_ns_icount;
983 	int dad_na_icount;
984 	struct callout dad_timer_ch;
985 };
986 
987 static struct dadq_head dadq;
988 static int dad_init = 0;
989 
990 static struct dadq *
991 nd6_dad_find(struct ifaddr *ifa)
992 {
993 	struct dadq *dp;
994 
995 	TAILQ_FOREACH(dp, &dadq, dad_list) {
996 		if (dp->dad_ifa == ifa)
997 			return dp;
998 	}
999 	return NULL;
1000 }
1001 
1002 static void
1003 nd6_dad_starttimer(struct dadq *dp, int ticks)
1004 {
1005 
1006 	callout_reset(&dp->dad_timer_ch, ticks,
1007 	    (void (*) (void *))nd6_dad_timer, (void *)dp->dad_ifa);
1008 }
1009 
1010 static void
1011 nd6_dad_stoptimer(struct dadq *dp)
1012 {
1013 
1014 	callout_stop(&dp->dad_timer_ch);
1015 }
1016 
1017 /*
1018  * Start Duplicated Address Detection (DAD) for specified interface address.
1019  */
1020 void
1021 nd6_dad_start(struct ifaddr *ifa,
1022 	      int *tick)	/* minimum delay ticks for IFF_UP event */
1023 {
1024 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1025 	struct dadq *dp;
1026 
1027 	if (!dad_init) {
1028 		TAILQ_INIT(&dadq);
1029 		dad_init++;
1030 	}
1031 
1032 	/*
1033 	 * If we don't need DAD, don't do it.
1034 	 * There are several cases:
1035 	 * - DAD is disabled (ip6_dad_count == 0)
1036 	 * - the interface address is anycast
1037 	 */
1038 	if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
1039 		log(LOG_DEBUG,
1040 			"nd6_dad_start: called with non-tentative address "
1041 			"%s(%s)\n",
1042 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1043 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1044 		return;
1045 	}
1046 	if (ia->ia6_flags & IN6_IFF_ANYCAST) {
1047 		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1048 		return;
1049 	}
1050 	if (!ip6_dad_count) {
1051 		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1052 		return;
1053 	}
1054 	if (!ifa->ifa_ifp)
1055 		panic("nd6_dad_start: ifa->ifa_ifp == NULL");
1056 	if (!(ifa->ifa_ifp->if_flags & IFF_UP))
1057 		return;
1058 	if (nd6_dad_find(ifa) != NULL) {
1059 		/* DAD already in progress */
1060 		return;
1061 	}
1062 
1063 	dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
1064 	if (dp == NULL) {
1065 		log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
1066 			"%s(%s)\n",
1067 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1068 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1069 		return;
1070 	}
1071 	bzero(dp, sizeof(*dp));
1072 	callout_init(&dp->dad_timer_ch);
1073 	TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
1074 
1075 	nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
1076 	    ip6_sprintf(&ia->ia_addr.sin6_addr)));
1077 
1078 	/*
1079 	 * Send NS packet for DAD, ip6_dad_count times.
1080 	 * Note that we must delay the first transmission, if this is the
1081 	 * first packet to be sent from the interface after interface
1082 	 * (re)initialization.
1083 	 */
1084 	dp->dad_ifa = ifa;
1085 	IFAREF(ifa);	/* just for safety */
1086 	dp->dad_count = ip6_dad_count;
1087 	dp->dad_ns_icount = dp->dad_na_icount = 0;
1088 	dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
1089 	if (tick == NULL) {
1090 		nd6_dad_ns_output(dp, ifa);
1091 		nd6_dad_starttimer(dp,
1092 		    ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1093 	} else {
1094 		int ntick;
1095 
1096 		if (*tick == 0)
1097 			ntick = random() % (MAX_RTR_SOLICITATION_DELAY * hz);
1098 		else
1099 			ntick = *tick + random() % (hz / 2);
1100 		*tick = ntick;
1101 		nd6_dad_starttimer(dp, ntick);
1102 	}
1103 }
1104 
1105 /*
1106  * terminate DAD unconditionally.  used for address removals.
1107  */
1108 void
1109 nd6_dad_stop(struct ifaddr *ifa)
1110 {
1111 	struct dadq *dp;
1112 
1113 	if (!dad_init)
1114 		return;
1115 	dp = nd6_dad_find(ifa);
1116 	if (!dp) {
1117 		/* DAD wasn't started yet */
1118 		return;
1119 	}
1120 
1121 	nd6_dad_stoptimer(dp);
1122 
1123 	TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1124 	free(dp, M_IP6NDP);
1125 	dp = NULL;
1126 	IFAFREE(ifa);
1127 }
1128 
1129 static void
1130 nd6_dad_timer(struct ifaddr *ifa)
1131 {
1132 	int s;
1133 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1134 	struct dadq *dp;
1135 
1136 	s = splnet();		/* XXX */
1137 
1138 	/* Sanity check */
1139 	if (ia == NULL) {
1140 		log(LOG_ERR, "nd6_dad_timer: called with null parameter\n");
1141 		goto done;
1142 	}
1143 	dp = nd6_dad_find(ifa);
1144 	if (dp == NULL) {
1145 		log(LOG_ERR, "nd6_dad_timer: DAD structure not found\n");
1146 		goto done;
1147 	}
1148 	if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
1149 		log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
1150 			"%s(%s)\n",
1151 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1152 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1153 		goto done;
1154 	}
1155 	if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
1156 		log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
1157 			"%s(%s)\n",
1158 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1159 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1160 		goto done;
1161 	}
1162 
1163 	/* timeouted with IFF_{RUNNING,UP} check */
1164 	if (dp->dad_ns_tcount > dad_maxtry) {
1165 		nd6log((LOG_INFO, "%s: could not run DAD, driver problem?\n",
1166 			if_name(ifa->ifa_ifp)));
1167 
1168 		TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1169 		free(dp, M_IP6NDP);
1170 		dp = NULL;
1171 		IFAFREE(ifa);
1172 		goto done;
1173 	}
1174 
1175 	/* Need more checks? */
1176 	if (dp->dad_ns_ocount < dp->dad_count) {
1177 		/*
1178 		 * We have more NS to go.  Send NS packet for DAD.
1179 		 */
1180 		nd6_dad_ns_output(dp, ifa);
1181 		nd6_dad_starttimer(dp,
1182 			ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1183 	} else {
1184 		/*
1185 		 * We have transmitted sufficient number of DAD packets.
1186 		 * See what we've got.
1187 		 */
1188 		int duplicate;
1189 
1190 		duplicate = 0;
1191 
1192 		if (dp->dad_na_icount) {
1193 			/*
1194 			 * the check is in nd6_dad_na_input(),
1195 			 * but just in case
1196 			 */
1197 			duplicate++;
1198 		}
1199 
1200 		if (dp->dad_ns_icount) {
1201 #if 0 /* heuristics */
1202 			/*
1203 			 * if
1204 			 * - we have sent many(?) DAD NS, and
1205 			 * - the number of NS we sent equals to the
1206 			 *   number of NS we've got, and
1207 			 * - we've got no NA
1208 			 * we may have a faulty network card/driver which
1209 			 * loops back multicasts to myself.
1210 			 */
1211 			if (3 < dp->dad_count
1212 			 && dp->dad_ns_icount == dp->dad_count
1213 			 && dp->dad_na_icount == 0) {
1214 				log(LOG_INFO, "DAD questionable for %s(%s): "
1215 					"network card loops back multicast?\n",
1216 					ip6_sprintf(&ia->ia_addr.sin6_addr),
1217 					if_name(ifa->ifa_ifp));
1218 				/* XXX consider it a duplicate or not? */
1219 				/* duplicate++; */
1220 			} else {
1221 				/* We've seen NS, means DAD has failed. */
1222 				duplicate++;
1223 			}
1224 #else
1225 			/* We've seen NS, means DAD has failed. */
1226 			duplicate++;
1227 #endif
1228 		}
1229 
1230 		if (duplicate) {
1231 			/* (*dp) will be freed in nd6_dad_duplicated() */
1232 			dp = NULL;
1233 			nd6_dad_duplicated(ifa);
1234 		} else {
1235 			/*
1236 			 * We are done with DAD.  No NA came, no NS came.
1237 			 * duplicated address found.
1238 			 */
1239 			ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1240 
1241 			nd6log((LOG_DEBUG,
1242 			    "%s: DAD complete for %s - no duplicates found\n",
1243 			    if_name(ifa->ifa_ifp),
1244 			    ip6_sprintf(&ia->ia_addr.sin6_addr)));
1245 
1246 			TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1247 			free(dp, M_IP6NDP);
1248 			dp = NULL;
1249 			IFAFREE(ifa);
1250 		}
1251 	}
1252 
1253 done:
1254 	splx(s);
1255 }
1256 
1257 void
1258 nd6_dad_duplicated(struct ifaddr *ifa)
1259 {
1260 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1261 	struct dadq *dp;
1262 
1263 	dp = nd6_dad_find(ifa);
1264 	if (dp == NULL) {
1265 		log(LOG_ERR, "nd6_dad_duplicated: DAD structure not found\n");
1266 		return;
1267 	}
1268 
1269 	log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
1270 	    "NS in/out=%d/%d, NA in=%d\n",
1271 	    if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr),
1272 	    dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_na_icount);
1273 
1274 	ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1275 	ia->ia6_flags |= IN6_IFF_DUPLICATED;
1276 
1277 	/* We are done with DAD, with duplicated address found. (failure) */
1278 	nd6_dad_stoptimer(dp);
1279 
1280 	log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
1281 	    if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr));
1282 	log(LOG_ERR, "%s: manual intervention required\n",
1283 	    if_name(ifa->ifa_ifp));
1284 
1285 	TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1286 	free(dp, M_IP6NDP);
1287 	dp = NULL;
1288 	IFAFREE(ifa);
1289 }
1290 
1291 static void
1292 nd6_dad_ns_output(struct dadq *dp, struct ifaddr *ifa)
1293 {
1294 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1295 	struct ifnet *ifp = ifa->ifa_ifp;
1296 
1297 	dp->dad_ns_tcount++;
1298 	if ((ifp->if_flags & IFF_UP) == 0) {
1299 #if 0
1300 		printf("%s: interface down?\n", if_name(ifp));
1301 #endif
1302 		return;
1303 	}
1304 	if ((ifp->if_flags & IFF_RUNNING) == 0) {
1305 #if 0
1306 		printf("%s: interface not running?\n", if_name(ifp));
1307 #endif
1308 		return;
1309 	}
1310 
1311 	dp->dad_ns_ocount++;
1312 	nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, 1);
1313 }
1314 
1315 static void
1316 nd6_dad_ns_input(struct ifaddr *ifa)
1317 {
1318 	struct in6_ifaddr *ia;
1319 	struct ifnet *ifp;
1320 	const struct in6_addr *taddr6;
1321 	struct dadq *dp;
1322 	int duplicate;
1323 
1324 	if (!ifa)
1325 		panic("ifa == NULL in nd6_dad_ns_input");
1326 
1327 	ia = (struct in6_ifaddr *)ifa;
1328 	ifp = ifa->ifa_ifp;
1329 	taddr6 = &ia->ia_addr.sin6_addr;
1330 	duplicate = 0;
1331 	dp = nd6_dad_find(ifa);
1332 
1333 	/* Quickhack - completely ignore DAD NS packets */
1334 	if (dad_ignore_ns) {
1335 		nd6log((LOG_INFO,
1336 		    "nd6_dad_ns_input: ignoring DAD NS packet for "
1337 		    "address %s(%s)\n", ip6_sprintf(taddr6),
1338 		    if_name(ifa->ifa_ifp)));
1339 		return;
1340 	}
1341 
1342 	/*
1343 	 * if I'm yet to start DAD, someone else started using this address
1344 	 * first.  I have a duplicate and you win.
1345 	 */
1346 	if (!dp || dp->dad_ns_ocount == 0)
1347 		duplicate++;
1348 
1349 	/* XXX more checks for loopback situation - see nd6_dad_timer too */
1350 
1351 	if (duplicate) {
1352 		dp = NULL;	/* will be freed in nd6_dad_duplicated() */
1353 		nd6_dad_duplicated(ifa);
1354 	} else {
1355 		/*
1356 		 * not sure if I got a duplicate.
1357 		 * increment ns count and see what happens.
1358 		 */
1359 		if (dp)
1360 			dp->dad_ns_icount++;
1361 	}
1362 }
1363 
1364 static void
1365 nd6_dad_na_input(struct ifaddr *ifa)
1366 {
1367 	struct dadq *dp;
1368 
1369 	if (!ifa)
1370 		panic("ifa == NULL in nd6_dad_na_input");
1371 
1372 	dp = nd6_dad_find(ifa);
1373 	if (dp)
1374 		dp->dad_na_icount++;
1375 
1376 	/* remove the address. */
1377 	nd6_dad_duplicated(ifa);
1378 }
1379