xref: /openbsd-src/sys/netinet6/nd6_nbr.c (revision f2da64fbbbf1b03f09f390ab01267c93dfd77c4c)
1 /*	$OpenBSD: nd6_nbr.c,v 1.110 2016/08/23 11:03:10 mpi Exp $	*/
2 /*	$KAME: nd6_nbr.c,v 1.61 2001/02/10 16:06:14 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 <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/malloc.h>
36 #include <sys/mbuf.h>
37 #include <sys/socket.h>
38 #include <sys/sockio.h>
39 #include <sys/time.h>
40 #include <sys/kernel.h>
41 #include <sys/ioctl.h>
42 #include <sys/syslog.h>
43 #include <sys/queue.h>
44 #include <sys/timeout.h>
45 
46 #include <net/if.h>
47 #include <net/if_var.h>
48 #include <net/if_types.h>
49 #include <net/if_dl.h>
50 #include <net/route.h>
51 
52 #include <netinet/in.h>
53 #include <netinet/if_ether.h>
54 #include <netinet6/in6_var.h>
55 #include <netinet/ip6.h>
56 #include <netinet6/ip6_var.h>
57 #include <netinet6/nd6.h>
58 #include <netinet/icmp6.h>
59 
60 #include "carp.h"
61 #if NCARP > 0
62 #include <netinet/ip_carp.h>
63 #endif
64 
65 TAILQ_HEAD(dadq_head, dadq);
66 struct dadq {
67 	TAILQ_ENTRY(dadq) dad_list;
68 	struct ifaddr *dad_ifa;
69 	int dad_count;		/* max NS to send */
70 	int dad_ns_tcount;	/* # of trials to send NS */
71 	int dad_ns_ocount;	/* NS sent so far */
72 	int dad_ns_icount;
73 	int dad_na_icount;
74 	struct timeout dad_timer_ch;
75 };
76 
77 struct dadq *nd6_dad_find(struct ifaddr *);
78 void nd6_dad_starttimer(struct dadq *, int);
79 void nd6_dad_stoptimer(struct dadq *);
80 void nd6_dad_timer(struct ifaddr *);
81 void nd6_dad_ns_output(struct dadq *, struct ifaddr *);
82 void nd6_dad_ns_input(struct ifaddr *);
83 void nd6_dad_duplicated(struct dadq *);
84 
85 int nd6_isneighbor(const struct ifnet *, const struct in6_addr *);
86 
87 static int dad_maxtry = 15;	/* max # of *tries* to transmit DAD packet */
88 
89 /*
90  * Input an Neighbor Solicitation Message.
91  *
92  * Based on RFC 2461
93  * Based on RFC 2462 (duplicated address detection)
94  */
95 void
96 nd6_ns_input(struct mbuf *m, int off, int icmp6len)
97 {
98 	struct ifnet *ifp;
99 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
100 	struct nd_neighbor_solicit *nd_ns;
101 	struct in6_addr saddr6 = ip6->ip6_src;
102 	struct in6_addr daddr6 = ip6->ip6_dst;
103 	struct in6_addr taddr6;
104 	struct in6_addr myaddr6;
105 	char *lladdr = NULL;
106 	struct ifaddr *ifa = NULL;
107 	int lladdrlen = 0;
108 	int anycast = 0, proxy = 0, tentative = 0;
109 	int router = ip6_forwarding;
110 	int tlladdr;
111 	union nd_opts ndopts;
112 	struct sockaddr_dl *proxydl = NULL;
113 	char addr[INET6_ADDRSTRLEN], addr0[INET6_ADDRSTRLEN];
114 
115 	ifp = if_get(m->m_pkthdr.ph_ifidx);
116 	if (ifp == NULL)
117 		goto freeit;
118 
119 	IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
120 	if (nd_ns == NULL) {
121 		icmp6stat.icp6s_tooshort++;
122 		if_put(ifp);
123 		return;
124 	}
125 	ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
126 	taddr6 = nd_ns->nd_ns_target;
127 
128 	if (ip6->ip6_hlim != 255) {
129 		nd6log((LOG_ERR,
130 		    "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
131 		    ip6->ip6_hlim,
132 		    inet_ntop(AF_INET6, &ip6->ip6_src, addr, sizeof(addr)),
133 		    inet_ntop(AF_INET6, &ip6->ip6_dst, addr0, sizeof(addr0)),
134 		    ifp->if_xname));
135 		goto bad;
136 	}
137 
138 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
139 		/* dst has to be solicited node multicast address. */
140 		/* don't check ifindex portion */
141 		if (daddr6.s6_addr16[0] == __IPV6_ADDR_INT16_MLL &&
142 		    daddr6.s6_addr32[1] == 0 &&
143 		    daddr6.s6_addr32[2] == __IPV6_ADDR_INT32_ONE &&
144 		    daddr6.s6_addr8[12] == 0xff) {
145 			; /*good*/
146 		} else {
147 			nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
148 			    "(wrong ip6 dst)\n"));
149 			goto bad;
150 		}
151 	} else {
152 		/*
153 		 * Make sure the source address is from a neighbor's address.
154 		 */
155 		if (!nd6_isneighbor(ifp, &saddr6)) {
156 			nd6log((LOG_INFO, "nd6_ns_input: "
157 			    "NS packet from non-neighbor\n"));
158 			goto bad;
159 		}
160 	}
161 
162 
163 	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
164 		nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
165 		goto bad;
166 	}
167 
168 	if (IN6_IS_SCOPE_EMBED(&taddr6))
169 		taddr6.s6_addr16[1] = htons(ifp->if_index);
170 
171 	icmp6len -= sizeof(*nd_ns);
172 	nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
173 	if (nd6_options(&ndopts) < 0) {
174 		nd6log((LOG_INFO,
175 		    "nd6_ns_input: invalid ND option, ignored\n"));
176 		/* nd6_options have incremented stats */
177 		goto freeit;
178 	}
179 
180 	if (ndopts.nd_opts_src_lladdr) {
181 		lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
182 		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
183 	}
184 
185 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
186 		nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
187 		    "(link-layer address option)\n"));
188 		goto bad;
189 	}
190 
191 	/*
192 	 * Attaching target link-layer address to the NA?
193 	 * (RFC 2461 7.2.4)
194 	 *
195 	 * NS IP dst is unicast/anycast			MUST NOT add
196 	 * NS IP dst is solicited-node multicast	MUST add
197 	 *
198 	 * In implementation, we add target link-layer address by default.
199 	 * We do not add one in MUST NOT cases.
200 	 */
201 #if 0 /* too much! */
202 	ifa = &in6ifa_ifpwithaddr(ifp, &daddr6)->ia_ifa;
203 	if (ifa && (ifatoia6(ifa)->ia6_flags & IN6_IFF_ANYCAST))
204 		tlladdr = 0;
205 	else
206 #endif
207 	if (!IN6_IS_ADDR_MULTICAST(&daddr6))
208 		tlladdr = 0;
209 	else
210 		tlladdr = 1;
211 
212 	/*
213 	 * Target address (taddr6) must be either:
214 	 * (1) Valid unicast/anycast address for my receiving interface,
215 	 * (2) Unicast address for which I'm offering proxy service, or
216 	 * (3) "tentative" address on which DAD is being performed.
217 	 */
218 	/* (1) and (3) check. */
219 	ifa = &in6ifa_ifpwithaddr(ifp, &taddr6)->ia_ifa;
220 #if NCARP > 0
221 	if (ifp->if_type == IFT_CARP && ifa && !carp_iamatch6(ifp))
222 		ifa = NULL;
223 #endif
224 
225 	/* (2) check. */
226 	if (!ifa) {
227 		struct rtentry *rt;
228 		struct sockaddr_in6 tsin6;
229 
230 		bzero(&tsin6, sizeof tsin6);
231 		tsin6.sin6_len = sizeof(struct sockaddr_in6);
232 		tsin6.sin6_family = AF_INET6;
233 		tsin6.sin6_addr = taddr6;
234 
235 		rt = rtalloc(sin6tosa(&tsin6), 0, m->m_pkthdr.ph_rtableid);
236 		if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
237 		    rt->rt_gateway->sa_family == AF_LINK) {
238 			/*
239 			 * proxy NDP for single entry
240 			 */
241 			ifa = &in6ifa_ifpforlinklocal(ifp, IN6_IFF_TENTATIVE|
242 			    IN6_IFF_DUPLICATED|IN6_IFF_ANYCAST)->ia_ifa;
243 			if (ifa) {
244 				proxy = 1;
245 				proxydl = satosdl(rt->rt_gateway);
246 				router = 0;	/* XXX */
247 			}
248 		}
249 		if (rt)
250 			rtfree(rt);
251 	}
252 	if (!ifa) {
253 		/*
254 		 * We've got an NS packet, and we don't have that address
255 		 * assigned for us.  We MUST silently ignore it.
256 		 * See RFC2461 7.2.3.
257 		 */
258 		goto freeit;
259 	}
260 	myaddr6 = *IFA_IN6(ifa);
261 	anycast = ifatoia6(ifa)->ia6_flags & IN6_IFF_ANYCAST;
262 	tentative = ifatoia6(ifa)->ia6_flags & IN6_IFF_TENTATIVE;
263 	if (ifatoia6(ifa)->ia6_flags & IN6_IFF_DUPLICATED)
264 		goto freeit;
265 
266 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
267 		nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
268 		    "(if %d, NS packet %d)\n",
269 		    inet_ntop(AF_INET6, &taddr6, addr, sizeof(addr)),
270 		    ifp->if_addrlen, lladdrlen - 2));
271 		goto bad;
272 	}
273 
274 	if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
275 		log(LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
276 		    inet_ntop(AF_INET6, &saddr6, addr, sizeof(addr)));
277 		goto freeit;
278 	}
279 
280 	/*
281 	 * We have neighbor solicitation packet, with target address equals to
282 	 * one of my tentative address.
283 	 *
284 	 * src addr	how to process?
285 	 * ---		---
286 	 * multicast	of course, invalid (rejected in ip6_input)
287 	 * unicast	somebody is doing address resolution -> ignore
288 	 * unspec	dup address detection
289 	 *
290 	 * The processing is defined in RFC 2462.
291 	 */
292 	if (tentative) {
293 		/*
294 		 * If source address is unspecified address, it is for
295 		 * duplicated address detection.
296 		 *
297 		 * If not, the packet is for address resolution;
298 		 * silently ignore it.
299 		 */
300 		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
301 			nd6_dad_ns_input(ifa);
302 
303 		goto freeit;
304 	}
305 
306 	/*
307 	 * If the source address is unspecified address, entries must not
308 	 * be created or updated.
309 	 * It looks that sender is performing DAD.  Output NA toward
310 	 * all-node multicast address, to tell the sender that I'm using
311 	 * the address.
312 	 * S bit ("solicited") must be zero.
313 	 */
314 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
315 		saddr6 = in6addr_linklocal_allnodes;
316 		saddr6.s6_addr16[1] = htons(ifp->if_index);
317 		nd6_na_output(ifp, &saddr6, &taddr6,
318 		    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
319 		    (router ? ND_NA_FLAG_ROUTER : 0),
320 		    tlladdr, sdltosa(proxydl));
321 		goto freeit;
322 	}
323 
324 	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0);
325 
326 	nd6_na_output(ifp, &saddr6, &taddr6,
327 	    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
328 	    (router ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
329 	    tlladdr, sdltosa(proxydl));
330  freeit:
331 	m_freem(m);
332 	if_put(ifp);
333 	return;
334 
335  bad:
336 	nd6log((LOG_ERR, "nd6_ns_input: src=%s\n",
337 	    inet_ntop(AF_INET6, &saddr6, addr, sizeof(addr))));
338 	nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n",
339 	    inet_ntop(AF_INET6, &daddr6, addr, sizeof(addr))));
340 	nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n",
341 	    inet_ntop(AF_INET6, &taddr6, addr, sizeof(addr))));
342 	icmp6stat.icp6s_badns++;
343 	m_freem(m);
344 	if_put(ifp);
345 }
346 
347 /*
348  * Output an Neighbor Solicitation Message. Caller specifies:
349  *	- ICMP6 header source IP6 address
350  *	- ND6 header target IP6 address
351  *	- ND6 header source datalink address
352  *
353  * Based on RFC 2461
354  * Based on RFC 2462 (duplicated address detection)
355  *
356  * ln - for source address determination
357  * dad - duplicated address detection
358  */
359 void
360 nd6_ns_output(struct ifnet *ifp, struct in6_addr *daddr6,
361     struct in6_addr *taddr6, struct llinfo_nd6 *ln, int dad)
362 {
363 	struct mbuf *m;
364 	struct ip6_hdr *ip6;
365 	struct nd_neighbor_solicit *nd_ns;
366 	struct sockaddr_in6 src_sa, dst_sa;
367 	struct ip6_moptions im6o;
368 	int icmp6len;
369 	int maxlen;
370 	caddr_t mac;
371 
372 	if (IN6_IS_ADDR_MULTICAST(taddr6))
373 		return;
374 
375 	/* estimate the size of message */
376 	maxlen = sizeof(*ip6) + sizeof(*nd_ns);
377 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
378 #ifdef DIAGNOSTIC
379 	if (max_linkhdr + maxlen >= MCLBYTES) {
380 		printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
381 		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
382 		panic("nd6_ns_output: insufficient MCLBYTES");
383 		/* NOTREACHED */
384 	}
385 #endif
386 
387 	MGETHDR(m, M_DONTWAIT, MT_DATA);
388 	if (m && max_linkhdr + maxlen >= MHLEN) {
389 		MCLGET(m, M_DONTWAIT);
390 		if ((m->m_flags & M_EXT) == 0) {
391 			m_free(m);
392 			m = NULL;
393 		}
394 	}
395 	if (m == NULL)
396 		return;
397 	m->m_pkthdr.ph_ifidx = 0;
398 	m->m_pkthdr.ph_rtableid = ifp->if_rdomain;
399 
400 	if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
401 		m->m_flags |= M_MCAST;
402 		im6o.im6o_ifidx = ifp->if_index;
403 		im6o.im6o_hlim = 255;
404 		im6o.im6o_loop = 0;
405 	}
406 
407 	icmp6len = sizeof(*nd_ns);
408 	m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
409 	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */
410 
411 	/* fill neighbor solicitation packet */
412 	ip6 = mtod(m, struct ip6_hdr *);
413 	ip6->ip6_flow = 0;
414 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
415 	ip6->ip6_vfc |= IPV6_VERSION;
416 	/* ip6->ip6_plen will be set later */
417 	ip6->ip6_nxt = IPPROTO_ICMPV6;
418 	ip6->ip6_hlim = 255;
419 	/* determine the source and destination addresses */
420 	bzero(&src_sa, sizeof(src_sa));
421 	bzero(&dst_sa, sizeof(dst_sa));
422 	src_sa.sin6_family = dst_sa.sin6_family = AF_INET6;
423 	src_sa.sin6_len = dst_sa.sin6_len = sizeof(struct sockaddr_in6);
424 	if (daddr6)
425 		dst_sa.sin6_addr = *daddr6;
426 	else {
427 		dst_sa.sin6_addr.s6_addr16[0] = __IPV6_ADDR_INT16_MLL;
428 		dst_sa.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
429 		dst_sa.sin6_addr.s6_addr32[1] = 0;
430 		dst_sa.sin6_addr.s6_addr32[2] = __IPV6_ADDR_INT32_ONE;
431 		dst_sa.sin6_addr.s6_addr32[3] = taddr6->s6_addr32[3];
432 		dst_sa.sin6_addr.s6_addr8[12] = 0xff;
433 	}
434 	ip6->ip6_dst = dst_sa.sin6_addr;
435 	if (!dad) {
436 		/*
437 		 * RFC2461 7.2.2:
438 		 * "If the source address of the packet prompting the
439 		 * solicitation is the same as one of the addresses assigned
440 		 * to the outgoing interface, that address SHOULD be placed
441 		 * in the IP Source Address of the outgoing solicitation.
442 		 * Otherwise, any one of the addresses assigned to the
443 		 * interface should be used."
444 		 *
445 		 * We use the source address for the prompting packet
446 		 * (saddr6), if:
447 		 * - saddr6 is given from the caller (by giving "ln"), and
448 		 * - saddr6 belongs to the outgoing interface.
449 		 * Otherwise, we perform the source address selection as usual.
450 		 */
451 		struct ip6_hdr *hip6;		/* hold ip6 */
452 		struct in6_addr *saddr6;
453 
454 		if (ln && ln->ln_hold) {
455 			hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
456 			/* XXX pullup? */
457 			if (sizeof(*hip6) < ln->ln_hold->m_len)
458 				saddr6 = &hip6->ip6_src;
459 			else
460 				saddr6 = NULL;
461 		} else
462 			saddr6 = NULL;
463 		if (saddr6 && in6ifa_ifpwithaddr(ifp, saddr6))
464 			src_sa.sin6_addr = *saddr6;
465 		else {
466 			struct rtentry *rt;
467 
468 			rt = rtalloc(sin6tosa(&dst_sa), RT_RESOLVE,
469 			    m->m_pkthdr.ph_rtableid);
470 			if (!rtisvalid(rt)) {
471 				char addr[INET6_ADDRSTRLEN];
472 
473 				nd6log((LOG_DEBUG,
474 				    "%s: source can't be determined: dst=%s\n",
475 				    __func__, inet_ntop(AF_INET6,
476 				    &dst_sa.sin6_addr, addr, sizeof(addr))));
477 				rtfree(rt);
478 				goto bad;
479 			}
480 			src_sa.sin6_addr =
481 			    ifatoia6(rt->rt_ifa)->ia_addr.sin6_addr;
482 			rtfree(rt);
483 		}
484 	} else {
485 		/*
486 		 * Source address for DAD packet must always be IPv6
487 		 * unspecified address. (0::0)
488 		 * We actually don't have to 0-clear the address (we did it
489 		 * above), but we do so here explicitly to make the intention
490 		 * clearer.
491 		 */
492 		bzero(&src_sa.sin6_addr, sizeof(src_sa.sin6_addr));
493 	}
494 	ip6->ip6_src = src_sa.sin6_addr;
495 	nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
496 	nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
497 	nd_ns->nd_ns_code = 0;
498 	nd_ns->nd_ns_reserved = 0;
499 	nd_ns->nd_ns_target = *taddr6;
500 
501 	if (IN6_IS_SCOPE_EMBED(&nd_ns->nd_ns_target))
502 		nd_ns->nd_ns_target.s6_addr16[1] = 0;
503 
504 	/*
505 	 * Add source link-layer address option.
506 	 *
507 	 *				spec		implementation
508 	 *				---		---
509 	 * DAD packet			MUST NOT	do not add the option
510 	 * there's no link layer address:
511 	 *				impossible	do not add the option
512 	 * there's link layer address:
513 	 *	Multicast NS		MUST add one	add the option
514 	 *	Unicast NS		SHOULD add one	add the option
515 	 */
516 	if (!dad && (mac = nd6_ifptomac(ifp))) {
517 		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
518 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
519 		/* 8 byte alignments... */
520 		optlen = (optlen + 7) & ~7;
521 
522 		m->m_pkthdr.len += optlen;
523 		m->m_len += optlen;
524 		icmp6len += optlen;
525 		bzero((caddr_t)nd_opt, optlen);
526 		nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
527 		nd_opt->nd_opt_len = optlen >> 3;
528 		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
529 	}
530 
531 	ip6->ip6_plen = htons((u_short)icmp6len);
532 	nd_ns->nd_ns_cksum = 0;
533 	m->m_pkthdr.csum_flags |= M_ICMP_CSUM_OUT;
534 
535 	ip6_output(m, NULL, NULL, dad ? IPV6_UNSPECSRC : 0, &im6o, NULL);
536 	icmp6stat.icp6s_outhist[ND_NEIGHBOR_SOLICIT]++;
537 	return;
538 
539   bad:
540 	m_freem(m);
541 }
542 
543 /*
544  * Neighbor advertisement input handling.
545  *
546  * Based on RFC 2461
547  * Based on RFC 2462 (duplicated address detection)
548  *
549  * the following items are not implemented yet:
550  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
551  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
552  */
553 void
554 nd6_na_input(struct mbuf *m, int off, int icmp6len)
555 {
556 	struct ifnet *ifp;
557 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
558 	struct nd_neighbor_advert *nd_na;
559 	struct in6_addr saddr6 = ip6->ip6_src;
560 	struct in6_addr daddr6 = ip6->ip6_dst;
561 	struct in6_addr taddr6;
562 	int flags;
563 	int is_router;
564 	int is_solicited;
565 	int is_override;
566 	char *lladdr = NULL;
567 	int lladdrlen = 0;
568 	struct ifaddr *ifa;
569 	struct llinfo_nd6 *ln;
570 	struct rtentry *rt = NULL;
571 	struct sockaddr_dl *sdl;
572 	union nd_opts ndopts;
573 	char addr[INET6_ADDRSTRLEN], addr0[INET6_ADDRSTRLEN];
574 
575 	ifp = if_get(m->m_pkthdr.ph_ifidx);
576 	if (ifp == NULL)
577 		goto freeit;
578 
579 	if (ip6->ip6_hlim != 255) {
580 		nd6log((LOG_ERR,
581 		    "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
582 		    ip6->ip6_hlim,
583 		    inet_ntop(AF_INET6, &ip6->ip6_src, addr, sizeof(addr)),
584 		    inet_ntop(AF_INET6, &ip6->ip6_dst, addr0, sizeof(addr0)),
585 		    ifp->if_xname));
586 		goto bad;
587 	}
588 
589 	IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
590 	if (nd_na == NULL) {
591 		icmp6stat.icp6s_tooshort++;
592 		if_put(ifp);
593 		return;
594 	}
595 	taddr6 = nd_na->nd_na_target;
596 	flags = nd_na->nd_na_flags_reserved;
597 	is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
598 	is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
599 	is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
600 
601 	if (IN6_IS_SCOPE_EMBED(&taddr6))
602 		taddr6.s6_addr16[1] = htons(ifp->if_index);
603 
604 	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
605 		nd6log((LOG_ERR,
606 		    "nd6_na_input: invalid target address %s\n",
607 		    inet_ntop(AF_INET6, &taddr6, addr, sizeof(addr))));
608 		goto bad;
609 	}
610 	if (is_solicited && IN6_IS_ADDR_MULTICAST(&daddr6)) {
611 		nd6log((LOG_ERR,
612 		    "nd6_na_input: a solicited adv is multicasted\n"));
613 		goto bad;
614 	}
615 
616 	icmp6len -= sizeof(*nd_na);
617 	nd6_option_init(nd_na + 1, icmp6len, &ndopts);
618 	if (nd6_options(&ndopts) < 0) {
619 		nd6log((LOG_INFO,
620 		    "nd6_na_input: invalid ND option, ignored\n"));
621 		/* nd6_options have incremented stats */
622 		goto freeit;
623 	}
624 
625 	if (IN6_IS_ADDR_MULTICAST(&daddr6) && !ndopts.nd_opts_tgt_lladdr) {
626 		nd6log((LOG_INFO,
627 		    "nd6_na_input: multicast adv without TLLA\n"));
628 		goto bad;
629 	}
630 
631 	if (ndopts.nd_opts_tgt_lladdr) {
632 		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
633 		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
634 	}
635 
636 	ifa = &in6ifa_ifpwithaddr(ifp, &taddr6)->ia_ifa;
637 
638 	/*
639 	 * Target address matches one of my interface address.
640 	 *
641 	 * If my address is tentative, this means that there's somebody
642 	 * already using the same address as mine.  This indicates DAD failure.
643 	 * This is defined in RFC 2462.
644 	 *
645 	 * Otherwise, process as defined in RFC 2461.
646 	 */
647 	if (ifa && (ifatoia6(ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
648 		struct dadq *dp;
649 
650 		dp = nd6_dad_find(ifa);
651 		if (dp) {
652 			dp->dad_na_icount++;
653 
654 			/* remove the address. */
655 			nd6_dad_duplicated(dp);
656 		}
657 		goto freeit;
658 	}
659 
660 	if (ifa) {
661 #if NCARP > 0
662 		/*
663 		 * Ignore NAs silently for carp addresses if we're not
664 		 * the CARP master.
665 		 */
666 		if (ifp->if_type == IFT_CARP && !carp_iamatch6(ifp))
667 			goto freeit;
668 #endif
669 		log(LOG_ERR,
670 		    "nd6_na_input: duplicate IP6 address %s\n",
671 		    inet_ntop(AF_INET6, &taddr6, addr, sizeof(addr)));
672 		goto freeit;
673 	}
674 	/*
675 	 * Make sure the source address is from a neighbor's address.
676 	 */
677 	if (!nd6_isneighbor(ifp, &saddr6)) {
678 		nd6log((LOG_INFO, "nd6_na_input: "
679 		    "ND packet from non-neighbor\n"));
680 		goto bad;
681 	}
682 
683 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
684 		nd6log((LOG_INFO, "nd6_na_input: lladdrlen mismatch for %s "
685 		    "(if %d, NA packet %d)\n",
686 		    inet_ntop(AF_INET6, &taddr6, addr, sizeof(addr)),
687 		    ifp->if_addrlen, lladdrlen - 2));
688 		goto bad;
689 	}
690 
691 	/*
692 	 * If no neighbor cache entry is found, NA SHOULD silently be
693 	 * discarded.
694 	 */
695 	rt = nd6_lookup(&taddr6, 0, ifp, ifp->if_rdomain);
696 	if ((rt == NULL) ||
697 	   ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) ||
698 	   ((sdl = satosdl(rt->rt_gateway)) == NULL))
699 		goto freeit;
700 
701 	if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
702 		/*
703 		 * If the link-layer has address, and no lladdr option came,
704 		 * discard the packet.
705 		 */
706 		if (ifp->if_addrlen && !lladdr)
707 			goto freeit;
708 
709 		/*
710 		 * Record link-layer address, and update the state.
711 		 */
712 		sdl->sdl_alen = ifp->if_addrlen;
713 		bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
714 		if (is_solicited) {
715 			ln->ln_state = ND6_LLINFO_REACHABLE;
716 			ln->ln_byhint = 0;
717 			if (!ND6_LLINFO_PERMANENT(ln)) {
718 				nd6_llinfo_settimer(ln,
719 				    ND_IFINFO(ifp)->reachable);
720 			}
721 		} else {
722 			ln->ln_state = ND6_LLINFO_STALE;
723 			nd6_llinfo_settimer(ln, nd6_gctimer);
724 		}
725 		if ((ln->ln_router = is_router) != 0) {
726 			/*
727 			 * This means a router's state has changed from
728 			 * non-reachable to probably reachable, and might
729 			 * affect the status of associated prefixes..
730 			 */
731 			pfxlist_onlink_check();
732 			if ((rt->rt_flags & RTF_LLINFO) == 0)
733 				goto freeit;	/* ln is gone */
734 		}
735 	} else {
736 		int llchange;
737 
738 		/*
739 		 * Check if the link-layer address has changed or not.
740 		 */
741 		if (!lladdr)
742 			llchange = 0;
743 		else {
744 			if (sdl->sdl_alen) {
745 				if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen))
746 					llchange = 1;
747 				else
748 					llchange = 0;
749 			} else
750 				llchange = 1;
751 		}
752 
753 		/*
754 		 * This is VERY complex.  Look at it with care.
755 		 *
756 		 * override solicit lladdr llchange	action
757 		 *					(L: record lladdr)
758 		 *
759 		 *	0	0	n	--	(2c)
760 		 *	0	0	y	n	(2b) L
761 		 *	0	0	y	y	(1)    REACHABLE->STALE
762 		 *	0	1	n	--	(2c)   *->REACHABLE
763 		 *	0	1	y	n	(2b) L *->REACHABLE
764 		 *	0	1	y	y	(1)    REACHABLE->STALE
765 		 *	1	0	n	--	(2a)
766 		 *	1	0	y	n	(2a) L
767 		 *	1	0	y	y	(2a) L *->STALE
768 		 *	1	1	n	--	(2a)   *->REACHABLE
769 		 *	1	1	y	n	(2a) L *->REACHABLE
770 		 *	1	1	y	y	(2a) L *->REACHABLE
771 		 */
772 		if (!is_override && (lladdr && llchange)) {	   /* (1) */
773 			/*
774 			 * If state is REACHABLE, make it STALE.
775 			 * no other updates should be done.
776 			 */
777 			if (ln->ln_state == ND6_LLINFO_REACHABLE) {
778 				ln->ln_state = ND6_LLINFO_STALE;
779 				nd6_llinfo_settimer(ln, nd6_gctimer);
780 			}
781 			goto freeit;
782 		} else if (is_override				   /* (2a) */
783 			|| (!is_override && (lladdr && !llchange)) /* (2b) */
784 			|| !lladdr) {				   /* (2c) */
785 			/*
786 			 * Update link-local address, if any.
787 			 */
788 			if (llchange) {
789 				log(LOG_INFO, "ndp info overwritten for %s "
790 				    "by %s on %s\n",
791 				    inet_ntop(AF_INET6, &taddr6,
792 					addr, sizeof(addr)),
793 				    ether_sprintf(lladdr), ifp->if_xname);
794 			}
795 			if (lladdr) {
796 				sdl->sdl_alen = ifp->if_addrlen;
797 				bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
798 			}
799 
800 			/*
801 			 * If solicited, make the state REACHABLE.
802 			 * If not solicited and the link-layer address was
803 			 * changed, make it STALE.
804 			 */
805 			if (is_solicited) {
806 				ln->ln_state = ND6_LLINFO_REACHABLE;
807 				ln->ln_byhint = 0;
808 				if (!ND6_LLINFO_PERMANENT(ln)) {
809 					nd6_llinfo_settimer(ln,
810 					    ND_IFINFO(ifp)->reachable);
811 				}
812 			} else {
813 				if (lladdr && llchange) {
814 					ln->ln_state = ND6_LLINFO_STALE;
815 					nd6_llinfo_settimer(ln, nd6_gctimer);
816 				}
817 			}
818 		}
819 
820 		if (ln->ln_router && !is_router) {
821 			/*
822 			 * The peer dropped the router flag.
823 			 * Remove the sender from the Default Router List and
824 			 * update the Destination Cache entries.
825 			 */
826 			struct nd_defrouter *dr;
827 			struct in6_addr *in6;
828 			int s;
829 
830 			in6 = &satosin6(rt_key(rt))->sin6_addr;
831 
832 			/*
833 			 * Lock to protect the default router list.
834 			 * XXX: this might be unnecessary, since this function
835 			 * is only called under the network software interrupt
836 			 * context.  However, we keep it just for safety.
837 			 */
838 			s = splsoftnet();
839 			dr = defrouter_lookup(in6, rt->rt_ifidx);
840 			if (dr)
841 				defrtrlist_del(dr);
842 			else if (!ip6_forwarding) {
843 				/*
844 				 * Even if the neighbor is not in the default
845 				 * router list, the neighbor may be used
846 				 * as a next hop for some destinations
847 				 * (e.g. redirect case). So we must
848 				 * call rt6_flush explicitly.
849 				 */
850 				rt6_flush(&ip6->ip6_src, ifp);
851 			}
852 			splx(s);
853 		}
854 		ln->ln_router = is_router;
855 	}
856 	rt->rt_flags &= ~RTF_REJECT;
857 	ln->ln_asked = 0;
858 	if (ln->ln_hold) {
859 		struct mbuf *n = ln->ln_hold;
860 		ln->ln_hold = NULL;
861 		/*
862 		 * we assume ifp is not a loopback here, so just set the 2nd
863 		 * argument as the 1st one.
864 		 */
865 		ifp->if_output(ifp, n, rt_key(rt), rt);
866 		if (ln->ln_hold == n) {
867 			/* n is back in ln_hold. Discard. */
868 			m_freem(ln->ln_hold);
869 			ln->ln_hold = NULL;
870 		}
871 	}
872 
873  freeit:
874  	rtfree(rt);
875 	m_freem(m);
876 	if_put(ifp);
877 	return;
878 
879  bad:
880 	icmp6stat.icp6s_badna++;
881 	m_freem(m);
882 	if_put(ifp);
883 }
884 
885 /*
886  * Neighbor advertisement output handling.
887  *
888  * Based on RFC 2461
889  *
890  * the following items are not implemented yet:
891  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
892  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
893  *
894  * tlladdr - 1 if include target link-layer address
895  * sdl0 - sockaddr_dl (= proxy NA) or NULL
896  */
897 void
898 nd6_na_output(struct ifnet *ifp, struct in6_addr *daddr6,
899     struct in6_addr *taddr6, u_long flags, int tlladdr,
900     struct sockaddr *sdl0)
901 {
902 	struct mbuf *m;
903 	struct rtentry *rt = NULL;
904 	struct ip6_hdr *ip6;
905 	struct nd_neighbor_advert *nd_na;
906 	struct ip6_moptions im6o;
907 	struct sockaddr_in6 dst_sa;
908 	int icmp6len, maxlen;
909 	caddr_t mac = NULL;
910 
911 	/* estimate the size of message */
912 	maxlen = sizeof(*ip6) + sizeof(*nd_na);
913 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
914 #ifdef DIAGNOSTIC
915 	if (max_linkhdr + maxlen >= MCLBYTES) {
916 		printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
917 		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
918 		panic("nd6_na_output: insufficient MCLBYTES");
919 		/* NOTREACHED */
920 	}
921 #endif
922 
923 	MGETHDR(m, M_DONTWAIT, MT_DATA);
924 	if (m && max_linkhdr + maxlen >= MHLEN) {
925 		MCLGET(m, M_DONTWAIT);
926 		if ((m->m_flags & M_EXT) == 0) {
927 			m_free(m);
928 			m = NULL;
929 		}
930 	}
931 	if (m == NULL)
932 		return;
933 	m->m_pkthdr.ph_ifidx = 0;
934 	m->m_pkthdr.ph_rtableid = ifp->if_rdomain;
935 
936 	if (IN6_IS_ADDR_MULTICAST(daddr6)) {
937 		m->m_flags |= M_MCAST;
938 		im6o.im6o_ifidx = ifp->if_index;
939 		im6o.im6o_hlim = 255;
940 		im6o.im6o_loop = 0;
941 	}
942 
943 	icmp6len = sizeof(*nd_na);
944 	m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
945 	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */
946 
947 	/* fill neighbor advertisement packet */
948 	ip6 = mtod(m, struct ip6_hdr *);
949 	ip6->ip6_flow = 0;
950 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
951 	ip6->ip6_vfc |= IPV6_VERSION;
952 	ip6->ip6_nxt = IPPROTO_ICMPV6;
953 	ip6->ip6_hlim = 255;
954 	bzero(&dst_sa, sizeof(dst_sa));
955 	dst_sa.sin6_len = sizeof(struct sockaddr_in6);
956 	dst_sa.sin6_family = AF_INET6;
957 	dst_sa.sin6_addr = *daddr6;
958 	if (IN6_IS_ADDR_UNSPECIFIED(daddr6)) {
959 		/* reply to DAD */
960 		dst_sa.sin6_addr.s6_addr16[0] = __IPV6_ADDR_INT16_MLL;
961 		dst_sa.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
962 		dst_sa.sin6_addr.s6_addr32[1] = 0;
963 		dst_sa.sin6_addr.s6_addr32[2] = 0;
964 		dst_sa.sin6_addr.s6_addr32[3] = __IPV6_ADDR_INT32_ONE;
965 
966 		flags &= ~ND_NA_FLAG_SOLICITED;
967 	}
968 	ip6->ip6_dst = dst_sa.sin6_addr;
969 
970 	/*
971 	 * Select a source whose scope is the same as that of the dest.
972 	 */
973 	rt = rtalloc(sin6tosa(&dst_sa), RT_RESOLVE, ifp->if_rdomain);
974 	if (!rtisvalid(rt)) {
975 		char addr[INET6_ADDRSTRLEN];
976 
977 		nd6log((LOG_DEBUG, "%s: source can't be determined: dst=%s\n",
978 		    __func__, inet_ntop(AF_INET6, &dst_sa.sin6_addr, addr,
979 		    sizeof(addr))));
980 		rtfree(rt);
981 		goto bad;
982 	}
983 	ip6->ip6_src = ifatoia6(rt->rt_ifa)->ia_addr.sin6_addr;
984 	rtfree(rt);
985 	nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
986 	nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
987 	nd_na->nd_na_code = 0;
988 	nd_na->nd_na_target = *taddr6;
989 	if (IN6_IS_SCOPE_EMBED(&nd_na->nd_na_target))
990 		nd_na->nd_na_target.s6_addr16[1] = 0;
991 
992 	/*
993 	 * "tlladdr" indicates NS's condition for adding tlladdr or not.
994 	 * see nd6_ns_input() for details.
995 	 * Basically, if NS packet is sent to unicast/anycast addr,
996 	 * target lladdr option SHOULD NOT be included.
997 	 */
998 	if (tlladdr) {
999 		/*
1000 		 * sdl0 != NULL indicates proxy NA.  If we do proxy, use
1001 		 * lladdr in sdl0.  If we are not proxying (sending NA for
1002 		 * my address) use lladdr configured for the interface.
1003 		 */
1004 		if (sdl0 == NULL) {
1005 			mac = nd6_ifptomac(ifp);
1006 		} else if (sdl0->sa_family == AF_LINK) {
1007 			struct sockaddr_dl *sdl;
1008 			sdl = satosdl(sdl0);
1009 			if (sdl->sdl_alen == ifp->if_addrlen)
1010 				mac = LLADDR(sdl);
1011 		}
1012 	}
1013 	if (tlladdr && mac) {
1014 		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
1015 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
1016 
1017 		/* roundup to 8 bytes alignment! */
1018 		optlen = (optlen + 7) & ~7;
1019 
1020 		m->m_pkthdr.len += optlen;
1021 		m->m_len += optlen;
1022 		icmp6len += optlen;
1023 		bzero((caddr_t)nd_opt, optlen);
1024 		nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
1025 		nd_opt->nd_opt_len = optlen >> 3;
1026 		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
1027 	} else
1028 		flags &= ~ND_NA_FLAG_OVERRIDE;
1029 
1030 #if NCARP > 0
1031 	/* Do not send NAs for carp addresses if we're not the CARP master. */
1032 	if (ifp->if_type == IFT_CARP && !carp_iamatch6(ifp))
1033 		goto bad;
1034 #endif
1035 
1036 	ip6->ip6_plen = htons((u_short)icmp6len);
1037 	nd_na->nd_na_flags_reserved = flags;
1038 	nd_na->nd_na_cksum = 0;
1039 	m->m_pkthdr.csum_flags |= M_ICMP_CSUM_OUT;
1040 
1041 	ip6_output(m, NULL, NULL, 0, &im6o, NULL);
1042 	icmp6stat.icp6s_outhist[ND_NEIGHBOR_ADVERT]++;
1043 	return;
1044 
1045   bad:
1046 	m_freem(m);
1047 }
1048 
1049 caddr_t
1050 nd6_ifptomac(struct ifnet *ifp)
1051 {
1052 	switch (ifp->if_type) {
1053 	case IFT_ETHER:
1054 	case IFT_IEEE1394:
1055 	case IFT_PROPVIRTUAL:
1056 	case IFT_CARP:
1057 	case IFT_IEEE80211:
1058 		return ((caddr_t)(ifp + 1));
1059 	default:
1060 		return NULL;
1061 	}
1062 }
1063 
1064 static struct dadq_head dadq;
1065 static int dad_init = 0;
1066 
1067 struct dadq *
1068 nd6_dad_find(struct ifaddr *ifa)
1069 {
1070 	struct dadq *dp;
1071 
1072 	TAILQ_FOREACH(dp, &dadq, dad_list) {
1073 		if (dp->dad_ifa == ifa)
1074 			return dp;
1075 	}
1076 	return NULL;
1077 }
1078 
1079 void
1080 nd6_dad_starttimer(struct dadq *dp, int ticks)
1081 {
1082 
1083 	timeout_set(&dp->dad_timer_ch, (void (*)(void *))nd6_dad_timer,
1084 	    (void *)dp->dad_ifa);
1085 	timeout_add(&dp->dad_timer_ch, ticks);
1086 }
1087 
1088 void
1089 nd6_dad_stoptimer(struct dadq *dp)
1090 {
1091 
1092 	timeout_del(&dp->dad_timer_ch);
1093 }
1094 
1095 /*
1096  * Start Duplicated Address Detection (DAD) for specified interface address.
1097  */
1098 void
1099 nd6_dad_start(struct ifaddr *ifa)
1100 {
1101 	struct in6_ifaddr *ia6 = ifatoia6(ifa);
1102 	struct dadq *dp;
1103 	char addr[INET6_ADDRSTRLEN];
1104 	int s;
1105 
1106 	if (!dad_init) {
1107 		TAILQ_INIT(&dadq);
1108 		dad_init++;
1109 	}
1110 
1111 	/*
1112 	 * If we don't need DAD, don't do it.
1113 	 * There are several cases:
1114 	 * - DAD is disabled (ip6_dad_count == 0)
1115 	 * - the interface address is anycast
1116 	 */
1117 	KASSERT(ia6->ia6_flags & IN6_IFF_TENTATIVE);
1118 	if ((ia6->ia6_flags & IN6_IFF_ANYCAST) || (!ip6_dad_count)) {
1119 		ia6->ia6_flags &= ~IN6_IFF_TENTATIVE;
1120 		return;
1121 	}
1122 
1123 	/* DAD already in progress */
1124 	if (nd6_dad_find(ifa) != NULL)
1125 		return;
1126 
1127 	dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT | M_ZERO);
1128 	if (dp == NULL) {
1129 		log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
1130 			"%s(%s)\n",
1131 			inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr,
1132 			    addr, sizeof(addr)),
1133 			ifa->ifa_ifp ? ifa->ifa_ifp->if_xname : "???");
1134 		return;
1135 	}
1136 	bzero(&dp->dad_timer_ch, sizeof(dp->dad_timer_ch));
1137 
1138 	s = splsoftnet();
1139 	TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
1140 	ip6_dad_pending++;
1141 
1142 	nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", ifa->ifa_ifp->if_xname,
1143 	    inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr, addr, sizeof(addr))));
1144 
1145 	/*
1146 	 * Send NS packet for DAD, ip6_dad_count times.
1147 	 * Note that we must delay the first transmission, if this is the
1148 	 * first packet to be sent from the interface after interface
1149 	 * (re)initialization.
1150 	 */
1151 	dp->dad_ifa = ifa;
1152 	ifa->ifa_refcnt++;	/* just for safety */
1153 	dp->dad_count = ip6_dad_count;
1154 	dp->dad_ns_icount = dp->dad_na_icount = 0;
1155 	dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
1156 	nd6_dad_ns_output(dp, ifa);
1157 	nd6_dad_starttimer(dp,
1158 	    (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1159 	splx(s);
1160 }
1161 
1162 /*
1163  * terminate DAD unconditionally.  used for address removals.
1164  */
1165 void
1166 nd6_dad_stop(struct ifaddr *ifa)
1167 {
1168 	struct dadq *dp;
1169 
1170 	if (!dad_init)
1171 		return;
1172 	dp = nd6_dad_find(ifa);
1173 	if (!dp) {
1174 		/* DAD wasn't started yet */
1175 		return;
1176 	}
1177 
1178 	nd6_dad_stoptimer(dp);
1179 
1180 	TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1181 	free(dp, M_IP6NDP, sizeof(*dp));
1182 	dp = NULL;
1183 	ifafree(ifa);
1184 	ip6_dad_pending--;
1185 }
1186 
1187 void
1188 nd6_dad_timer(struct ifaddr *ifa)
1189 {
1190 	int s;
1191 	struct in6_ifaddr *ia6 = ifatoia6(ifa);
1192 	struct dadq *dp;
1193 	char addr[INET6_ADDRSTRLEN];
1194 
1195 	s = splsoftnet();		/* XXX */
1196 
1197 	/* Sanity check */
1198 	if (ia6 == NULL) {
1199 		log(LOG_ERR, "nd6_dad_timer: called with null parameter\n");
1200 		goto done;
1201 	}
1202 	dp = nd6_dad_find(ifa);
1203 	if (dp == NULL) {
1204 		log(LOG_ERR, "nd6_dad_timer: DAD structure not found\n");
1205 		goto done;
1206 	}
1207 	if (ia6->ia6_flags & IN6_IFF_DUPLICATED) {
1208 		log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
1209 			"%s(%s)\n",
1210 			inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr,
1211 			    addr, sizeof(addr)),
1212 			ifa->ifa_ifp ? ifa->ifa_ifp->if_xname : "???");
1213 		goto done;
1214 	}
1215 	if ((ia6->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
1216 		log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
1217 			"%s(%s)\n",
1218 			inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr,
1219 			    addr, sizeof(addr)),
1220 			ifa->ifa_ifp ? ifa->ifa_ifp->if_xname : "???");
1221 		goto done;
1222 	}
1223 
1224 	/* timeouted with IFF_{RUNNING,UP} check */
1225 	if (dp->dad_ns_tcount > dad_maxtry) {
1226 		nd6log((LOG_INFO, "%s: could not run DAD, driver problem?\n",
1227 			ifa->ifa_ifp->if_xname));
1228 
1229 		TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1230 		free(dp, M_IP6NDP, sizeof(*dp));
1231 		dp = NULL;
1232 		ifafree(ifa);
1233 		ip6_dad_pending--;
1234 		goto done;
1235 	}
1236 
1237 	/* Need more checks? */
1238 	if (dp->dad_ns_ocount < dp->dad_count) {
1239 		/*
1240 		 * We have more NS to go.  Send NS packet for DAD.
1241 		 */
1242 		nd6_dad_ns_output(dp, ifa);
1243 		nd6_dad_starttimer(dp,
1244 		    (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1245 	} else {
1246 		/*
1247 		 * We have transmitted sufficient number of DAD packets.
1248 		 * See what we've got.
1249 		 */
1250 		int duplicate;
1251 
1252 		duplicate = 0;
1253 
1254 		if (dp->dad_na_icount) {
1255 			duplicate++;
1256 		}
1257 
1258 		if (dp->dad_ns_icount) {
1259 			/* We've seen NS, means DAD has failed. */
1260 			duplicate++;
1261 		}
1262 
1263 		if (duplicate) {
1264 			/* dp will be freed in nd6_dad_duplicated() */
1265 			nd6_dad_duplicated(dp);
1266 		} else {
1267 			/*
1268 			 * We are done with DAD.  No NA came, no NS came.
1269 			 * duplicated address found.
1270 			 */
1271 			ia6->ia6_flags &= ~IN6_IFF_TENTATIVE;
1272 
1273 			nd6log((LOG_DEBUG,
1274 			    "%s: DAD complete for %s - no duplicates found\n",
1275 			    ifa->ifa_ifp->if_xname,
1276 			    inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr,
1277 				addr, sizeof(addr))));
1278 
1279 			TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1280 			free(dp, M_IP6NDP, sizeof(*dp));
1281 			dp = NULL;
1282 			ifafree(ifa);
1283 			ip6_dad_pending--;
1284 		}
1285 	}
1286 
1287 done:
1288 	splx(s);
1289 }
1290 
1291 void
1292 nd6_dad_duplicated(struct dadq *dp)
1293 {
1294 	struct in6_ifaddr *ia6 = ifatoia6(dp->dad_ifa);
1295 	char addr[INET6_ADDRSTRLEN];
1296 
1297 	log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
1298 	    "NS in/out=%d/%d, NA in=%d\n",
1299 	    ia6->ia_ifp->if_xname,
1300 	    inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr, addr, sizeof(addr)),
1301 	    dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_na_icount);
1302 
1303 	ia6->ia6_flags &= ~IN6_IFF_TENTATIVE;
1304 	ia6->ia6_flags |= IN6_IFF_DUPLICATED;
1305 
1306 	/* We are done with DAD, with duplicated address found. (failure) */
1307 	nd6_dad_stoptimer(dp);
1308 
1309 	log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
1310 	    ia6->ia_ifp->if_xname,
1311 	    inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr, addr, sizeof(addr)));
1312 	log(LOG_ERR, "%s: manual intervention required\n",
1313 	    ia6->ia_ifp->if_xname);
1314 
1315 	TAILQ_REMOVE(&dadq, dp, dad_list);
1316 	ifafree(dp->dad_ifa);
1317 	free(dp, M_IP6NDP, sizeof(*dp));
1318 	ip6_dad_pending--;
1319 }
1320 
1321 void
1322 nd6_dad_ns_output(struct dadq *dp, struct ifaddr *ifa)
1323 {
1324 	struct in6_ifaddr *ia6 = ifatoia6(ifa);
1325 	struct ifnet *ifp = ifa->ifa_ifp;
1326 
1327 	dp->dad_ns_tcount++;
1328 	if ((ifp->if_flags & IFF_UP) == 0) {
1329 #if 0
1330 		printf("%s: interface down?\n", ifp->if_xname);
1331 #endif
1332 		return;
1333 	}
1334 	if ((ifp->if_flags & IFF_RUNNING) == 0) {
1335 #if 0
1336 		printf("%s: interface not running?\n", ifp->if_xname);
1337 #endif
1338 		return;
1339 	}
1340 
1341 	dp->dad_ns_ocount++;
1342 	nd6_ns_output(ifp, NULL, &ia6->ia_addr.sin6_addr, NULL, 1);
1343 }
1344 
1345 void
1346 nd6_dad_ns_input(struct ifaddr *ifa)
1347 {
1348 	struct dadq *dp;
1349 	int duplicate;
1350 
1351 	if (!ifa)
1352 		panic("ifa == NULL in nd6_dad_ns_input");
1353 
1354 	duplicate = 0;
1355 	dp = nd6_dad_find(ifa);
1356 
1357 	/*
1358 	 * if I'm yet to start DAD, someone else started using this address
1359 	 * first.  I have a duplicate and you win.
1360 	 */
1361 	if (!dp || dp->dad_ns_ocount == 0)
1362 		duplicate++;
1363 
1364 	/* XXX more checks for loopback situation - see nd6_dad_timer too */
1365 
1366 	if (duplicate) {
1367 		/* dp will be freed in nd6_dad_duplicated() */
1368 		nd6_dad_duplicated(dp);
1369 	} else {
1370 		/*
1371 		 * not sure if I got a duplicate.
1372 		 * increment ns count and see what happens.
1373 		 */
1374 		if (dp)
1375 			dp->dad_ns_icount++;
1376 	}
1377 }
1378 
1379 /*
1380  * Check whether ``addr'' is a neighbor address connected to ``ifp''.
1381  */
1382 int
1383 nd6_isneighbor(const struct ifnet *ifp, const struct in6_addr *addr)
1384 {
1385 	struct rtentry		*rt;
1386 	struct sockaddr_in6	 sin6;
1387 	unsigned int		 tableid = ifp->if_rdomain;
1388 	int rv = 0;
1389 
1390 	memset(&sin6, 0, sizeof(sin6));
1391 	sin6.sin6_len = sizeof(struct sockaddr_in6);
1392 	sin6.sin6_family = AF_INET6;
1393 	sin6.sin6_addr = *addr;
1394 	rt = rtalloc(sin6tosa(&sin6), 0, tableid);
1395 
1396 	if (rtisvalid(rt) && ISSET(rt->rt_flags, RTF_CLONING|RTF_CLONED))
1397 		rv = if_isconnected(ifp, rt->rt_ifidx);
1398 
1399 	rtfree(rt);
1400 	return (rv);
1401 }
1402