xref: /freebsd/sys/netinet6/nd6_nbr.c (revision 1404c3a4b87f21b33148e520ed889d1f8374ea37)
1 /*	$FreeBSD$	*/
2 /*	$KAME: nd6_nbr.c,v 1.86 2002/01/21 02:33:04 jinmei Exp $	*/
3 
4 /*-
5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the project nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #include "opt_inet.h"
34 #include "opt_inet6.h"
35 #include "opt_ipsec.h"
36 #include "opt_carp.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/if_var.h>
55 #include <net/route.h>
56 
57 #include <netinet/in.h>
58 #include <netinet/in_var.h>
59 #include <netinet6/in6_var.h>
60 #include <netinet/ip6.h>
61 #include <netinet6/ip6_var.h>
62 #include <netinet6/nd6.h>
63 #include <netinet/icmp6.h>
64 
65 #ifdef DEV_CARP
66 #include <netinet/ip_carp.h>
67 #endif
68 
69 #include <net/net_osdep.h>
70 
71 #define SDL(s) ((struct sockaddr_dl *)s)
72 
73 struct dadq;
74 static struct dadq *nd6_dad_find __P((struct ifaddr *));
75 static void nd6_dad_starttimer __P((struct dadq *, int));
76 static void nd6_dad_stoptimer __P((struct dadq *));
77 static void nd6_dad_timer __P((struct ifaddr *));
78 static void nd6_dad_ns_output __P((struct dadq *, struct ifaddr *));
79 static void nd6_dad_ns_input __P((struct ifaddr *));
80 static void nd6_dad_na_input __P((struct ifaddr *));
81 
82 static int dad_ignore_ns = 0;	/* ignore NS in DAD - specwise incorrect*/
83 static int dad_maxtry = 15;	/* max # of *tries* to transmit DAD packet */
84 
85 /*
86  * Input a Neighbor Solicitation Message.
87  *
88  * Based on RFC 2461
89  * Based on RFC 2462 (duplicated address detection)
90  */
91 void
92 nd6_ns_input(m, off, icmp6len)
93 	struct mbuf *m;
94 	int off, 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 = NULL;
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 #ifdef DEV_CARP
204 	if (ifp->if_carp)
205 		ifa = carp_iamatch6(ifp->if_carp, &taddr6);
206 	if (!ifa)
207 		ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
208 #else
209 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
210 #endif
211 
212 	/* (2) check. */
213 	if (!ifa) {
214 		struct rtentry *rt;
215 		struct sockaddr_in6 tsin6;
216 		int need_proxy;
217 
218 		bzero(&tsin6, sizeof tsin6);
219 		tsin6.sin6_len = sizeof(struct sockaddr_in6);
220 		tsin6.sin6_family = AF_INET6;
221 		tsin6.sin6_addr = taddr6;
222 
223 		rt = rtalloc1((struct sockaddr *)&tsin6, 0, 0);
224 		need_proxy = (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
225 		    rt->rt_gateway->sa_family == AF_LINK);
226 		if (rt)
227 			rtfree(rt);
228 		if (need_proxy) {
229 			/*
230 			 * proxy NDP for single entry
231 			 */
232 			ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
233 				IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
234 			if (ifa) {
235 				proxy = 1;
236 				proxydl = SDL(rt->rt_gateway);
237 			}
238 		}
239 	}
240 	if (!ifa) {
241 		/*
242 		 * We've got an NS packet, and we don't have that adddress
243 		 * assigned for us.  We MUST silently ignore it.
244 		 * See RFC2461 7.2.3.
245 		 */
246 		goto freeit;
247 	}
248 	myaddr6 = *IFA_IN6(ifa);
249 	anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
250 	tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
251 	if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
252 		goto freeit;
253 
254 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
255 		nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
256 		    "(if %d, NS packet %d)\n",
257 		    ip6_sprintf(&taddr6),
258 		    ifp->if_addrlen, lladdrlen - 2));
259 		goto bad;
260 	}
261 
262 	if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
263 		nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
264 		    ip6_sprintf(&saddr6)));
265 		goto freeit;
266 	}
267 
268 	/*
269 	 * We have neighbor solicitation packet, with target address equals to
270 	 * one of my tentative address.
271 	 *
272 	 * src addr	how to process?
273 	 * ---		---
274 	 * multicast	of course, invalid (rejected in ip6_input)
275 	 * unicast	somebody is doing address resolution -> ignore
276 	 * unspec	dup address detection
277 	 *
278 	 * The processing is defined in RFC 2462.
279 	 */
280 	if (tentative) {
281 		/*
282 		 * If source address is unspecified address, it is for
283 		 * duplicated address detection.
284 		 *
285 		 * If not, the packet is for addess resolution;
286 		 * silently ignore it.
287 		 */
288 		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
289 			nd6_dad_ns_input(ifa);
290 
291 		goto freeit;
292 	}
293 
294 	/*
295 	 * If the source address is unspecified address, entries must not
296 	 * be created or updated.
297 	 * It looks that sender is performing DAD.  Output NA toward
298 	 * all-node multicast address, to tell the sender that I'm using
299 	 * the address.
300 	 * S bit ("solicited") must be zero.
301 	 */
302 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
303 		saddr6 = in6addr_linklocal_allnodes;
304 		saddr6.s6_addr16[1] = htons(ifp->if_index);
305 		nd6_na_output(ifp, &saddr6, &taddr6,
306 		    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
307 		    (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
308 		    tlladdr, (struct sockaddr *)proxydl);
309 		goto freeit;
310 	}
311 
312 	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen,
313 	    ND_NEIGHBOR_SOLICIT, 0);
314 
315 	nd6_na_output(ifp, &saddr6, &taddr6,
316 	    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
317 	    (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
318 	    tlladdr, (struct sockaddr *)proxydl);
319  freeit:
320 	m_freem(m);
321 	return;
322 
323  bad:
324 	nd6log((LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6)));
325 	nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6)));
326 	nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6)));
327 	icmp6stat.icp6s_badns++;
328 	m_freem(m);
329 }
330 
331 /*
332  * Output a Neighbor Solicitation Message. Caller specifies:
333  *	- ICMP6 header source IP6 address
334  *	- ND6 header target IP6 address
335  *	- ND6 header source datalink address
336  *
337  * Based on RFC 2461
338  * Based on RFC 2462 (duplicated address detection)
339  */
340 void
341 nd6_ns_output(ifp, daddr6, taddr6, ln, dad)
342 	struct ifnet *ifp;
343 	const struct in6_addr *daddr6, *taddr6;
344 	struct llinfo_nd6 *ln;	/* for source address determination */
345 	int dad;	/* duplicated address detection */
346 {
347 	struct mbuf *m;
348 	struct ip6_hdr *ip6;
349 	struct nd_neighbor_solicit *nd_ns;
350 	struct in6_ifaddr *ia = NULL;
351 	struct ip6_moptions im6o;
352 	int icmp6len;
353 	int maxlen;
354 	caddr_t mac;
355 	struct ifnet *outif = NULL;
356 
357 	if (IN6_IS_ADDR_MULTICAST(taddr6))
358 		return;
359 
360 	/* estimate the size of message */
361 	maxlen = sizeof(*ip6) + sizeof(*nd_ns);
362 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
363 	if (max_linkhdr + maxlen >= MCLBYTES) {
364 #ifdef DIAGNOSTIC
365 		printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
366 		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
367 #endif
368 		return;
369 	}
370 
371 	MGETHDR(m, M_DONTWAIT, MT_DATA);
372 	if (m && max_linkhdr + maxlen >= MHLEN) {
373 		MCLGET(m, M_DONTWAIT);
374 		if ((m->m_flags & M_EXT) == 0) {
375 			m_free(m);
376 			m = NULL;
377 		}
378 	}
379 	if (m == NULL)
380 		return;
381 	m->m_pkthdr.rcvif = NULL;
382 
383 	if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
384 		m->m_flags |= M_MCAST;
385 		im6o.im6o_multicast_ifp = ifp;
386 		im6o.im6o_multicast_hlim = 255;
387 		im6o.im6o_multicast_loop = 0;
388 	}
389 
390 	icmp6len = sizeof(*nd_ns);
391 	m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
392 	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */
393 
394 	/* fill neighbor solicitation packet */
395 	ip6 = mtod(m, struct ip6_hdr *);
396 	ip6->ip6_flow = 0;
397 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
398 	ip6->ip6_vfc |= IPV6_VERSION;
399 	/* ip6->ip6_plen will be set later */
400 	ip6->ip6_nxt = IPPROTO_ICMPV6;
401 	ip6->ip6_hlim = 255;
402 	if (daddr6)
403 		ip6->ip6_dst = *daddr6;
404 	else {
405 		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
406 		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
407 		ip6->ip6_dst.s6_addr32[1] = 0;
408 		ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
409 		ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
410 		ip6->ip6_dst.s6_addr8[12] = 0xff;
411 	}
412 	if (!dad) {
413 		/*
414 		 * RFC2461 7.2.2:
415 		 * "If the source address of the packet prompting the
416 		 * solicitation is the same as one of the addresses assigned
417 		 * to the outgoing interface, that address SHOULD be placed
418 		 * in the IP Source Address of the outgoing solicitation.
419 		 * Otherwise, any one of the addresses assigned to the
420 		 * interface should be used."
421 		 *
422 		 * We use the source address for the prompting packet
423 		 * (saddr6), if:
424 		 * - saddr6 is given from the caller (by giving "ln"), and
425 		 * - saddr6 belongs to the outgoing interface.
426 		 * Otherwise, we perform a scope-wise match.
427 		 */
428 		struct ip6_hdr *hip6;		/* hold ip6 */
429 		struct in6_addr *saddr6;
430 
431 		if (ln && ln->ln_hold) {
432 			hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
433 			/* XXX pullup? */
434 			if (sizeof(*hip6) < ln->ln_hold->m_len)
435 				saddr6 = &hip6->ip6_src;
436 			else
437 				saddr6 = NULL;
438 		} else
439 			saddr6 = NULL;
440 		if (saddr6 && in6ifa_ifpwithaddr(ifp, saddr6))
441 			bcopy(saddr6, &ip6->ip6_src, sizeof(*saddr6));
442 		else {
443 			ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
444 			if (ia == NULL) {
445 				m_freem(m);
446 				return;
447 			}
448 			ip6->ip6_src = ia->ia_addr.sin6_addr;
449 		}
450 	} else {
451 		/*
452 		 * Source address for DAD packet must always be IPv6
453 		 * unspecified address. (0::0)
454 		 */
455 		bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
456 	}
457 	nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
458 	nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
459 	nd_ns->nd_ns_code = 0;
460 	nd_ns->nd_ns_reserved = 0;
461 	nd_ns->nd_ns_target = *taddr6;
462 	in6_clearscope(&nd_ns->nd_ns_target); /* XXX */
463 
464 	/*
465 	 * Add source link-layer address option.
466 	 *
467 	 *				spec		implementation
468 	 *				---		---
469 	 * DAD packet			MUST NOT	do not add the option
470 	 * there's no link layer address:
471 	 *				impossible	do not add the option
472 	 * there's link layer address:
473 	 *	Multicast NS		MUST add one	add the option
474 	 *	Unicast NS		SHOULD add one	add the option
475 	 */
476 	if (!dad && (mac = nd6_ifptomac(ifp))) {
477 		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
478 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
479 		/* 8 byte alignments... */
480 		optlen = (optlen + 7) & ~7;
481 
482 		m->m_pkthdr.len += optlen;
483 		m->m_len += optlen;
484 		icmp6len += optlen;
485 		bzero((caddr_t)nd_opt, optlen);
486 		nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
487 		nd_opt->nd_opt_len = optlen >> 3;
488 		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
489 	}
490 
491 	ip6->ip6_plen = htons((u_short)icmp6len);
492 	nd_ns->nd_ns_cksum = 0;
493 	nd_ns->nd_ns_cksum =
494 	    in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
495 
496 	ip6_output(m, NULL, NULL, dad ? IPV6_DADOUTPUT : 0, &im6o, &outif, NULL);
497 	if (outif) {
498 		icmp6_ifstat_inc(outif, ifs6_out_msg);
499 		icmp6_ifstat_inc(outif, ifs6_out_neighborsolicit);
500 	}
501 	icmp6stat.icp6s_outhist[ND_NEIGHBOR_SOLICIT]++;
502 }
503 
504 /*
505  * Neighbor advertisement input handling.
506  *
507  * Based on RFC 2461
508  * Based on RFC 2462 (duplicated address detection)
509  *
510  * the following items are not implemented yet:
511  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
512  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
513  */
514 void
515 nd6_na_input(m, off, icmp6len)
516 	struct mbuf *m;
517 	int off, icmp6len;
518 {
519 	struct ifnet *ifp = m->m_pkthdr.rcvif;
520 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
521 	struct nd_neighbor_advert *nd_na;
522 	struct in6_addr daddr6 = ip6->ip6_dst;
523 	struct in6_addr taddr6;
524 	int flags;
525 	int is_router;
526 	int is_solicited;
527 	int is_override;
528 	char *lladdr = NULL;
529 	int lladdrlen = 0;
530 	struct ifaddr *ifa;
531 	struct llinfo_nd6 *ln;
532 	struct rtentry *rt;
533 	struct sockaddr_dl *sdl;
534 	union nd_opts ndopts;
535 
536 	if (ip6->ip6_hlim != 255) {
537 		nd6log((LOG_ERR,
538 		    "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
539 		    ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
540 		    ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
541 		goto bad;
542 	}
543 
544 #ifndef PULLDOWN_TEST
545 	IP6_EXTHDR_CHECK(m, off, icmp6len,);
546 	nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
547 #else
548 	IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
549 	if (nd_na == NULL) {
550 		icmp6stat.icp6s_tooshort++;
551 		return;
552 	}
553 #endif
554 	taddr6 = nd_na->nd_na_target;
555 	flags = nd_na->nd_na_flags_reserved;
556 	is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
557 	is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
558 	is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
559 
560 	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
561 		taddr6.s6_addr16[1] = htons(ifp->if_index);
562 
563 	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
564 		nd6log((LOG_ERR,
565 		    "nd6_na_input: invalid target address %s\n",
566 		    ip6_sprintf(&taddr6)));
567 		goto bad;
568 	}
569 	if (IN6_IS_ADDR_MULTICAST(&daddr6))
570 		if (is_solicited) {
571 			nd6log((LOG_ERR,
572 			    "nd6_na_input: a solicited adv is multicasted\n"));
573 			goto bad;
574 		}
575 
576 	icmp6len -= sizeof(*nd_na);
577 	nd6_option_init(nd_na + 1, icmp6len, &ndopts);
578 	if (nd6_options(&ndopts) < 0) {
579 		nd6log((LOG_INFO,
580 		    "nd6_na_input: invalid ND option, ignored\n"));
581 		/* nd6_options have incremented stats */
582 		goto freeit;
583 	}
584 
585 	if (ndopts.nd_opts_tgt_lladdr) {
586 		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
587 		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
588 	}
589 
590 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
591 
592 	/*
593 	 * Target address matches one of my interface address.
594 	 *
595 	 * If my address is tentative, this means that there's somebody
596 	 * already using the same address as mine.  This indicates DAD failure.
597 	 * This is defined in RFC 2462.
598 	 *
599 	 * Otherwise, process as defined in RFC 2461.
600 	 */
601 	if (ifa
602 	 && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
603 		nd6_dad_na_input(ifa);
604 		goto freeit;
605 	}
606 
607 	/* Just for safety, maybe unnecessary. */
608 	if (ifa) {
609 		log(LOG_ERR,
610 		    "nd6_na_input: duplicate IP6 address %s\n",
611 		    ip6_sprintf(&taddr6));
612 		goto freeit;
613 	}
614 
615 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
616 		nd6log((LOG_INFO, "nd6_na_input: lladdrlen mismatch for %s "
617 		    "(if %d, NA packet %d)\n", ip6_sprintf(&taddr6),
618 		    ifp->if_addrlen, lladdrlen - 2));
619 		goto bad;
620 	}
621 
622 	/*
623 	 * If no neighbor cache entry is found, NA SHOULD silently be
624 	 * discarded.
625 	 */
626 	rt = nd6_lookup(&taddr6, 0, ifp);
627 	if ((rt == NULL) ||
628 	   ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) ||
629 	   ((sdl = SDL(rt->rt_gateway)) == NULL))
630 		goto freeit;
631 
632 	if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
633 		/*
634 		 * If the link-layer has address, and no lladdr option came,
635 		 * discard the packet.
636 		 */
637 		if (ifp->if_addrlen && !lladdr)
638 			goto freeit;
639 
640 		/*
641 		 * Record link-layer address, and update the state.
642 		 */
643 		sdl->sdl_alen = ifp->if_addrlen;
644 		bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
645 		if (is_solicited) {
646 			ln->ln_state = ND6_LLINFO_REACHABLE;
647 			ln->ln_byhint = 0;
648 			if (ln->ln_expire) {
649 				ln->ln_expire = time_second +
650 				    ND_IFINFO(rt->rt_ifp)->reachable;
651 			}
652 		} else {
653 			ln->ln_state = ND6_LLINFO_STALE;
654 			ln->ln_expire = time_second + nd6_gctimer;
655 		}
656 		if ((ln->ln_router = is_router) != 0) {
657 			/*
658 			 * This means a router's state has changed from
659 			 * non-reachable to probably reachable, and might
660 			 * affect the status of associated prefixes..
661 			 */
662 			pfxlist_onlink_check();
663 		}
664 	} else {
665 		int llchange;
666 
667 		/*
668 		 * Check if the link-layer address has changed or not.
669 		 */
670 		if (!lladdr)
671 			llchange = 0;
672 		else {
673 			if (sdl->sdl_alen) {
674 				if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen))
675 					llchange = 1;
676 				else
677 					llchange = 0;
678 			} else
679 				llchange = 1;
680 		}
681 
682 		/*
683 		 * This is VERY complex.  Look at it with care.
684 		 *
685 		 * override solicit lladdr llchange	action
686 		 *					(L: record lladdr)
687 		 *
688 		 *	0	0	n	--	(2c)
689 		 *	0	0	y	n	(2b) L
690 		 *	0	0	y	y	(1)    REACHABLE->STALE
691 		 *	0	1	n	--	(2c)   *->REACHABLE
692 		 *	0	1	y	n	(2b) L *->REACHABLE
693 		 *	0	1	y	y	(1)    REACHABLE->STALE
694 		 *	1	0	n	--	(2a)
695 		 *	1	0	y	n	(2a) L
696 		 *	1	0	y	y	(2a) L *->STALE
697 		 *	1	1	n	--	(2a)   *->REACHABLE
698 		 *	1	1	y	n	(2a) L *->REACHABLE
699 		 *	1	1	y	y	(2a) L *->REACHABLE
700 		 */
701 		if (!is_override && (lladdr && llchange)) {	   /* (1) */
702 			/*
703 			 * If state is REACHABLE, make it STALE.
704 			 * no other updates should be done.
705 			 */
706 			if (ln->ln_state == ND6_LLINFO_REACHABLE) {
707 				ln->ln_state = ND6_LLINFO_STALE;
708 				ln->ln_expire = time_second + nd6_gctimer;
709 			}
710 			goto freeit;
711 		} else if (is_override				   /* (2a) */
712 			|| (!is_override && (lladdr && !llchange)) /* (2b) */
713 			|| !lladdr) {				   /* (2c) */
714 			/*
715 			 * Update link-local address, if any.
716 			 */
717 			if (lladdr) {
718 				sdl->sdl_alen = ifp->if_addrlen;
719 				bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
720 			}
721 
722 			/*
723 			 * If solicited, make the state REACHABLE.
724 			 * If not solicited and the link-layer address was
725 			 * changed, make it STALE.
726 			 */
727 			if (is_solicited) {
728 				ln->ln_state = ND6_LLINFO_REACHABLE;
729 				ln->ln_byhint = 0;
730 				if (ln->ln_expire) {
731 					ln->ln_expire = time_second +
732 					    ND_IFINFO(ifp)->reachable;
733 				}
734 			} else {
735 				if (lladdr && llchange) {
736 					ln->ln_state = ND6_LLINFO_STALE;
737 					ln->ln_expire = time_second + nd6_gctimer;
738 				}
739 			}
740 		}
741 
742 		if (ln->ln_router && !is_router) {
743 			/*
744 			 * The peer dropped the router flag.
745 			 * Remove the sender from the Default Router List and
746 			 * update the Destination Cache entries.
747 			 */
748 			struct nd_defrouter *dr;
749 			struct in6_addr *in6;
750 			int s;
751 
752 			in6 = &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr;
753 
754 			/*
755 			 * Lock to protect the default router list.
756 			 * XXX: this might be unnecessary, since this function
757 			 * is only called under the network software interrupt
758 			 * context.  However, we keep it just for safety.
759 			 */
760 			s = splnet();
761 			dr = defrouter_lookup(in6, ifp);
762 			if (dr)
763 				defrtrlist_del(dr);
764 			else if (!ip6_forwarding && ip6_accept_rtadv) {
765 				/*
766 				 * Even if the neighbor is not in the default
767 				 * router list, the neighbor may be used
768 				 * as a next hop for some destinations
769 				 * (e.g. redirect case). So we must
770 				 * call rt6_flush explicitly.
771 				 */
772 				rt6_flush(&ip6->ip6_src, ifp);
773 			}
774 			splx(s);
775 		}
776 		ln->ln_router = is_router;
777 	}
778 	rt->rt_flags &= ~RTF_REJECT;
779 	ln->ln_asked = 0;
780 	if (ln->ln_hold) {
781 		/*
782 		 * we assume ifp is not a loopback here, so just set the 2nd
783 		 * argument as the 1st one.
784 		 */
785 		nd6_output(ifp, ifp, ln->ln_hold,
786 			   (struct sockaddr_in6 *)rt_key(rt), rt);
787 		ln->ln_hold = NULL;
788 	}
789 
790  freeit:
791 	m_freem(m);
792 	return;
793 
794  bad:
795 	icmp6stat.icp6s_badna++;
796 	m_freem(m);
797 }
798 
799 /*
800  * Neighbor advertisement output handling.
801  *
802  * Based on RFC 2461
803  *
804  * the following items are not implemented yet:
805  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
806  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
807  */
808 void
809 nd6_na_output(ifp, daddr6, taddr6, flags, tlladdr, sdl0)
810 	struct ifnet *ifp;
811 	const struct in6_addr *daddr6, *taddr6;
812 	u_long flags;
813 	int tlladdr;		/* 1 if include target link-layer address */
814 	struct sockaddr *sdl0;	/* sockaddr_dl (= proxy NA) or NULL */
815 {
816 	struct mbuf *m;
817 	struct ip6_hdr *ip6;
818 	struct nd_neighbor_advert *nd_na;
819 	struct in6_ifaddr *ia = NULL;
820 	struct ip6_moptions im6o;
821 	int icmp6len;
822 	int maxlen;
823 	caddr_t mac = NULL;
824 	struct ifnet *outif = NULL;
825 
826 	/* estimate the size of message */
827 	maxlen = sizeof(*ip6) + sizeof(*nd_na);
828 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
829 	if (max_linkhdr + maxlen >= MCLBYTES) {
830 #ifdef DIAGNOSTIC
831 		printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
832 		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
833 #endif
834 		return;
835 	}
836 
837 	MGETHDR(m, M_DONTWAIT, MT_DATA);
838 	if (m && max_linkhdr + maxlen >= MHLEN) {
839 		MCLGET(m, M_DONTWAIT);
840 		if ((m->m_flags & M_EXT) == 0) {
841 			m_free(m);
842 			m = NULL;
843 		}
844 	}
845 	if (m == NULL)
846 		return;
847 	m->m_pkthdr.rcvif = NULL;
848 
849 	if (IN6_IS_ADDR_MULTICAST(daddr6)) {
850 		m->m_flags |= M_MCAST;
851 		im6o.im6o_multicast_ifp = ifp;
852 		im6o.im6o_multicast_hlim = 255;
853 		im6o.im6o_multicast_loop = 0;
854 	}
855 
856 	icmp6len = sizeof(*nd_na);
857 	m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
858 	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */
859 
860 	/* fill neighbor advertisement packet */
861 	ip6 = mtod(m, struct ip6_hdr *);
862 	ip6->ip6_flow = 0;
863 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
864 	ip6->ip6_vfc |= IPV6_VERSION;
865 	ip6->ip6_nxt = IPPROTO_ICMPV6;
866 	ip6->ip6_hlim = 255;
867 	if (IN6_IS_ADDR_UNSPECIFIED(daddr6)) {
868 		/* reply to DAD */
869 		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
870 		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
871 		ip6->ip6_dst.s6_addr32[1] = 0;
872 		ip6->ip6_dst.s6_addr32[2] = 0;
873 		ip6->ip6_dst.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
874 		flags &= ~ND_NA_FLAG_SOLICITED;
875 	} else
876 		ip6->ip6_dst = *daddr6;
877 
878 	/*
879 	 * Select a source whose scope is the same as that of the dest.
880 	 */
881 	ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
882 	if (ia == NULL) {
883 		m_freem(m);
884 		return;
885 	}
886 	ip6->ip6_src = ia->ia_addr.sin6_addr;
887 	nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
888 	nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
889 	nd_na->nd_na_code = 0;
890 	nd_na->nd_na_target = *taddr6;
891 	in6_clearscope(&nd_na->nd_na_target); /* XXX */
892 
893 	/*
894 	 * "tlladdr" indicates NS's condition for adding tlladdr or not.
895 	 * see nd6_ns_input() for details.
896 	 * Basically, if NS packet is sent to unicast/anycast addr,
897 	 * target lladdr option SHOULD NOT be included.
898 	 */
899 	if (tlladdr) {
900 		/*
901 		 * sdl0 != NULL indicates proxy NA.  If we do proxy, use
902 		 * lladdr in sdl0.  If we are not proxying (sending NA for
903 		 * my address) use lladdr configured for the interface.
904 		 */
905 		if (sdl0 == NULL) {
906 #ifdef DEV_CARP
907 			if (ifp->if_carp)
908 				mac = carp_macmatch6(ifp->if_carp, m, taddr6);
909 			if (mac == NULL)
910 				mac = nd6_ifptomac(ifp);
911 #else
912 			mac = nd6_ifptomac(ifp);
913 #endif
914 		} else if (sdl0->sa_family == AF_LINK) {
915 			struct sockaddr_dl *sdl;
916 			sdl = (struct sockaddr_dl *)sdl0;
917 			if (sdl->sdl_alen == ifp->if_addrlen)
918 				mac = LLADDR(sdl);
919 		}
920 	}
921 	if (tlladdr && mac) {
922 		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
923 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
924 
925 		/* roundup to 8 bytes alignment! */
926 		optlen = (optlen + 7) & ~7;
927 
928 		m->m_pkthdr.len += optlen;
929 		m->m_len += optlen;
930 		icmp6len += optlen;
931 		bzero((caddr_t)nd_opt, optlen);
932 		nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
933 		nd_opt->nd_opt_len = optlen >> 3;
934 		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
935 	} else
936 		flags &= ~ND_NA_FLAG_OVERRIDE;
937 
938 	ip6->ip6_plen = htons((u_short)icmp6len);
939 	nd_na->nd_na_flags_reserved = flags;
940 	nd_na->nd_na_cksum = 0;
941 	nd_na->nd_na_cksum =
942 	    in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
943 
944 	ip6_output(m, NULL, NULL, 0, &im6o, &outif, NULL);
945 	if (outif) {
946 		icmp6_ifstat_inc(outif, ifs6_out_msg);
947 		icmp6_ifstat_inc(outif, ifs6_out_neighboradvert);
948 	}
949 	icmp6stat.icp6s_outhist[ND_NEIGHBOR_ADVERT]++;
950 }
951 
952 caddr_t
953 nd6_ifptomac(ifp)
954 	struct ifnet *ifp;
955 {
956 	switch (ifp->if_type) {
957 	case IFT_ARCNET:
958 	case IFT_ETHER:
959 	case IFT_FDDI:
960 	case IFT_IEEE1394:
961 #ifdef IFT_L2VLAN
962 	case IFT_L2VLAN:
963 #endif
964 #ifdef IFT_IEEE80211
965 	case IFT_IEEE80211:
966 #endif
967 #ifdef IFT_CARP
968 	case IFT_CARP:
969 #endif
970 	case IFT_ISO88025:
971 		return IF_LLADDR(ifp);
972 	default:
973 		return NULL;
974 	}
975 }
976 
977 TAILQ_HEAD(dadq_head, dadq);
978 struct dadq {
979 	TAILQ_ENTRY(dadq) dad_list;
980 	struct ifaddr *dad_ifa;
981 	int dad_count;		/* max NS to send */
982 	int dad_ns_tcount;	/* # of trials to send NS */
983 	int dad_ns_ocount;	/* NS sent so far */
984 	int dad_ns_icount;
985 	int dad_na_icount;
986 	struct callout dad_timer_ch;
987 };
988 
989 static struct dadq_head dadq;
990 static int dad_init = 0;
991 
992 static struct dadq *
993 nd6_dad_find(ifa)
994 	struct ifaddr *ifa;
995 {
996 	struct dadq *dp;
997 
998 	for (dp = dadq.tqh_first; dp; dp = dp->dad_list.tqe_next) {
999 		if (dp->dad_ifa == ifa)
1000 			return dp;
1001 	}
1002 	return NULL;
1003 }
1004 
1005 static void
1006 nd6_dad_starttimer(dp, ticks)
1007 	struct dadq *dp;
1008 	int ticks;
1009 {
1010 
1011 	callout_reset(&dp->dad_timer_ch, ticks,
1012 	    (void (*) __P((void *)))nd6_dad_timer, (void *)dp->dad_ifa);
1013 }
1014 
1015 static void
1016 nd6_dad_stoptimer(dp)
1017 	struct dadq *dp;
1018 {
1019 
1020 	callout_stop(&dp->dad_timer_ch);
1021 }
1022 
1023 /*
1024  * Start Duplicated Address Detection (DAD) for specified interface address.
1025  */
1026 void
1027 nd6_dad_start(ifa, tick)
1028 	struct ifaddr *ifa;
1029 	int *tick;	/* minimum delay ticks for IFF_UP event */
1030 {
1031 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1032 	struct dadq *dp;
1033 
1034 	if (!dad_init) {
1035 		TAILQ_INIT(&dadq);
1036 		dad_init++;
1037 	}
1038 
1039 	/*
1040 	 * If we don't need DAD, don't do it.
1041 	 * There are several cases:
1042 	 * - DAD is disabled (ip6_dad_count == 0)
1043 	 * - the interface address is anycast
1044 	 */
1045 	if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
1046 		log(LOG_DEBUG,
1047 			"nd6_dad_start: called with non-tentative address "
1048 			"%s(%s)\n",
1049 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1050 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1051 		return;
1052 	}
1053 	if (ia->ia6_flags & IN6_IFF_ANYCAST) {
1054 		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1055 		return;
1056 	}
1057 	if (!ip6_dad_count) {
1058 		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1059 		return;
1060 	}
1061 	if (!ifa->ifa_ifp)
1062 		panic("nd6_dad_start: ifa->ifa_ifp == NULL");
1063 	if (!(ifa->ifa_ifp->if_flags & IFF_UP)) {
1064 		return;
1065 	}
1066 	if (nd6_dad_find(ifa) != NULL) {
1067 		/* DAD already in progress */
1068 		return;
1069 	}
1070 
1071 	dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
1072 	if (dp == NULL) {
1073 		log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
1074 			"%s(%s)\n",
1075 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1076 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1077 		return;
1078 	}
1079 	bzero(dp, sizeof(*dp));
1080 	callout_init(&dp->dad_timer_ch, 0);
1081 	TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
1082 
1083 	nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
1084 	    ip6_sprintf(&ia->ia_addr.sin6_addr)));
1085 
1086 	/*
1087 	 * Send NS packet for DAD, ip6_dad_count times.
1088 	 * Note that we must delay the first transmission, if this is the
1089 	 * first packet to be sent from the interface after interface
1090 	 * (re)initialization.
1091 	 */
1092 	dp->dad_ifa = ifa;
1093 	IFAREF(ifa);	/* just for safety */
1094 	dp->dad_count = ip6_dad_count;
1095 	dp->dad_ns_icount = dp->dad_na_icount = 0;
1096 	dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
1097 	if (tick == NULL) {
1098 		nd6_dad_ns_output(dp, ifa);
1099 		nd6_dad_starttimer(dp,
1100 		    ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1101 	} else {
1102 		int ntick;
1103 
1104 		if (*tick == 0)
1105 			ntick = arc4random() % (MAX_RTR_SOLICITATION_DELAY * hz);
1106 		else
1107 			ntick = *tick + arc4random() % (hz / 2);
1108 		*tick = ntick;
1109 		nd6_dad_starttimer(dp, ntick);
1110 	}
1111 }
1112 
1113 /*
1114  * terminate DAD unconditionally.  used for address removals.
1115  */
1116 void
1117 nd6_dad_stop(ifa)
1118 	struct ifaddr *ifa;
1119 {
1120 	struct dadq *dp;
1121 
1122 	if (!dad_init)
1123 		return;
1124 	dp = nd6_dad_find(ifa);
1125 	if (!dp) {
1126 		/* DAD wasn't started yet */
1127 		return;
1128 	}
1129 
1130 	nd6_dad_stoptimer(dp);
1131 
1132 	TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1133 	free(dp, M_IP6NDP);
1134 	dp = NULL;
1135 	IFAFREE(ifa);
1136 }
1137 
1138 static void
1139 nd6_dad_timer(ifa)
1140 	struct ifaddr *ifa;
1141 {
1142 	int s;
1143 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1144 	struct dadq *dp;
1145 
1146 	s = splnet();		/* XXX */
1147 
1148 	/* Sanity check */
1149 	if (ia == NULL) {
1150 		log(LOG_ERR, "nd6_dad_timer: called with null parameter\n");
1151 		goto done;
1152 	}
1153 	dp = nd6_dad_find(ifa);
1154 	if (dp == NULL) {
1155 		log(LOG_ERR, "nd6_dad_timer: DAD structure not found\n");
1156 		goto done;
1157 	}
1158 	if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
1159 		log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
1160 			"%s(%s)\n",
1161 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1162 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1163 		goto done;
1164 	}
1165 	if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
1166 		log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
1167 			"%s(%s)\n",
1168 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1169 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1170 		goto done;
1171 	}
1172 
1173 	/* timeouted with IFF_{RUNNING,UP} check */
1174 	if (dp->dad_ns_tcount > dad_maxtry) {
1175 		nd6log((LOG_INFO, "%s: could not run DAD, driver problem?\n",
1176 		    if_name(ifa->ifa_ifp)));
1177 
1178 		TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1179 		free(dp, M_IP6NDP);
1180 		dp = NULL;
1181 		IFAFREE(ifa);
1182 		goto done;
1183 	}
1184 
1185 	/* Need more checks? */
1186 	if (dp->dad_ns_ocount < dp->dad_count) {
1187 		/*
1188 		 * We have more NS to go.  Send NS packet for DAD.
1189 		 */
1190 		nd6_dad_ns_output(dp, ifa);
1191 		nd6_dad_starttimer(dp,
1192 		    ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1193 	} else {
1194 		/*
1195 		 * We have transmitted sufficient number of DAD packets.
1196 		 * See what we've got.
1197 		 */
1198 		int duplicate;
1199 
1200 		duplicate = 0;
1201 
1202 		if (dp->dad_na_icount) {
1203 			/*
1204 			 * the check is in nd6_dad_na_input(),
1205 			 * but just in case
1206 			 */
1207 			duplicate++;
1208 		}
1209 
1210 		if (dp->dad_ns_icount) {
1211 #if 0 /* heuristics */
1212 			/*
1213 			 * if
1214 			 * - we have sent many(?) DAD NS, and
1215 			 * - the number of NS we sent equals to the
1216 			 *   number of NS we've got, and
1217 			 * - we've got no NA
1218 			 * we may have a faulty network card/driver which
1219 			 * loops back multicasts to myself.
1220 			 */
1221 			if (3 < dp->dad_count
1222 			 && dp->dad_ns_icount == dp->dad_count
1223 			 && dp->dad_na_icount == 0) {
1224 				log(LOG_INFO, "DAD questionable for %s(%s): "
1225 				    "network card loops back multicast?\n",
1226 				    ip6_sprintf(&ia->ia_addr.sin6_addr),
1227 				    if_name(ifa->ifa_ifp));
1228 				/* XXX consider it a duplicate or not? */
1229 				/* duplicate++; */
1230 			} else {
1231 				/* We've seen NS, means DAD has failed. */
1232 				duplicate++;
1233 			}
1234 #else
1235 			/* We've seen NS, means DAD has failed. */
1236 			duplicate++;
1237 #endif
1238 		}
1239 
1240 		if (duplicate) {
1241 			/* (*dp) will be freed in nd6_dad_duplicated() */
1242 			dp = NULL;
1243 			nd6_dad_duplicated(ifa);
1244 		} else {
1245 			/*
1246 			 * We are done with DAD.  No NA came, no NS came.
1247 			 * duplicated address found.
1248 			 */
1249 			ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1250 
1251 			nd6log((LOG_DEBUG,
1252 			    "%s: DAD complete for %s - no duplicates found\n",
1253 			    if_name(ifa->ifa_ifp),
1254 			    ip6_sprintf(&ia->ia_addr.sin6_addr)));
1255 
1256 			TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1257 			free(dp, M_IP6NDP);
1258 			dp = NULL;
1259 			IFAFREE(ifa);
1260 		}
1261 	}
1262 
1263 done:
1264 	splx(s);
1265 }
1266 
1267 void
1268 nd6_dad_duplicated(ifa)
1269 	struct ifaddr *ifa;
1270 {
1271 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1272 	struct dadq *dp;
1273 
1274 	dp = nd6_dad_find(ifa);
1275 	if (dp == NULL) {
1276 		log(LOG_ERR, "nd6_dad_duplicated: DAD structure not found\n");
1277 		return;
1278 	}
1279 
1280 	log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
1281 	    "NS in/out=%d/%d, NA in=%d\n",
1282 	    if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr),
1283 	    dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_na_icount);
1284 
1285 	ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1286 	ia->ia6_flags |= IN6_IFF_DUPLICATED;
1287 
1288 	/* We are done with DAD, with duplicated address found. (failure) */
1289 	nd6_dad_stoptimer(dp);
1290 
1291 	log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
1292 	    if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr));
1293 	log(LOG_ERR, "%s: manual intervention required\n",
1294 	    if_name(ifa->ifa_ifp));
1295 
1296 	TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1297 	free(dp, M_IP6NDP);
1298 	dp = NULL;
1299 	IFAFREE(ifa);
1300 }
1301 
1302 static void
1303 nd6_dad_ns_output(dp, ifa)
1304 	struct dadq *dp;
1305 	struct ifaddr *ifa;
1306 {
1307 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1308 	struct ifnet *ifp = ifa->ifa_ifp;
1309 
1310 	dp->dad_ns_tcount++;
1311 	if ((ifp->if_flags & IFF_UP) == 0) {
1312 #if 0
1313 		printf("%s: interface down?\n", if_name(ifp));
1314 #endif
1315 		return;
1316 	}
1317 	if ((ifp->if_flags & IFF_RUNNING) == 0) {
1318 #if 0
1319 		printf("%s: interface not running?\n", if_name(ifp));
1320 #endif
1321 		return;
1322 	}
1323 
1324 	dp->dad_ns_ocount++;
1325 	nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, 1);
1326 }
1327 
1328 static void
1329 nd6_dad_ns_input(ifa)
1330 	struct ifaddr *ifa;
1331 {
1332 	struct in6_ifaddr *ia;
1333 	struct ifnet *ifp;
1334 	const struct in6_addr *taddr6;
1335 	struct dadq *dp;
1336 	int duplicate;
1337 
1338 	if (!ifa)
1339 		panic("ifa == NULL in nd6_dad_ns_input");
1340 
1341 	ia = (struct in6_ifaddr *)ifa;
1342 	ifp = ifa->ifa_ifp;
1343 	taddr6 = &ia->ia_addr.sin6_addr;
1344 	duplicate = 0;
1345 	dp = nd6_dad_find(ifa);
1346 
1347 	/* Quickhack - completely ignore DAD NS packets */
1348 	if (dad_ignore_ns) {
1349 		nd6log((LOG_INFO,
1350 		    "nd6_dad_ns_input: ignoring DAD NS packet for "
1351 		    "address %s(%s)\n", ip6_sprintf(taddr6),
1352 		    if_name(ifa->ifa_ifp)));
1353 		return;
1354 	}
1355 
1356 	/*
1357 	 * if I'm yet to start DAD, someone else started using this address
1358 	 * first.  I have a duplicate and you win.
1359 	 */
1360 	if (!dp || dp->dad_ns_ocount == 0)
1361 		duplicate++;
1362 
1363 	/* XXX more checks for loopback situation - see nd6_dad_timer too */
1364 
1365 	if (duplicate) {
1366 		dp = NULL;	/* will be freed in nd6_dad_duplicated() */
1367 		nd6_dad_duplicated(ifa);
1368 	} else {
1369 		/*
1370 		 * not sure if I got a duplicate.
1371 		 * increment ns count and see what happens.
1372 		 */
1373 		if (dp)
1374 			dp->dad_ns_icount++;
1375 	}
1376 }
1377 
1378 static void
1379 nd6_dad_na_input(ifa)
1380 	struct ifaddr *ifa;
1381 {
1382 	struct dadq *dp;
1383 
1384 	if (!ifa)
1385 		panic("ifa == NULL in nd6_dad_na_input");
1386 
1387 	dp = nd6_dad_find(ifa);
1388 	if (dp)
1389 		dp->dad_na_icount++;
1390 
1391 	/* remove the address. */
1392 	nd6_dad_duplicated(ifa);
1393 }
1394