1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * $KAME: nd6_nbr.c,v 1.86 2002/01/21 02:33:04 jinmei Exp $
32 */
33
34 #include <sys/cdefs.h>
35 #include "opt_inet.h"
36 #include "opt_inet6.h"
37 #include "opt_ipsec.h"
38
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/eventhandler.h>
42 #include <sys/malloc.h>
43 #include <sys/libkern.h>
44 #include <sys/lock.h>
45 #include <sys/rwlock.h>
46 #include <sys/mbuf.h>
47 #include <sys/socket.h>
48 #include <sys/sockio.h>
49 #include <sys/time.h>
50 #include <sys/kernel.h>
51 #include <sys/errno.h>
52 #include <sys/sysctl.h>
53 #include <sys/syslog.h>
54 #include <sys/queue.h>
55 #include <sys/callout.h>
56 #include <sys/refcount.h>
57
58 #include <net/if.h>
59 #include <net/if_types.h>
60 #include <net/if_dl.h>
61 #include <net/if_var.h>
62 #include <net/route.h>
63 #include <net/vnet.h>
64
65 #include <netinet/in.h>
66 #include <netinet/in_var.h>
67 #include <net/if_llatbl.h>
68 #include <netinet6/in6_var.h>
69 #include <netinet6/in6_ifattach.h>
70 #include <netinet/ip6.h>
71 #include <netinet6/ip6_var.h>
72 #include <netinet6/scope6_var.h>
73 #include <netinet6/nd6.h>
74 #include <netinet/icmp6.h>
75 #include <netinet/ip_carp.h>
76 #include <netinet6/send.h>
77
78 #define SDL(s) ((struct sockaddr_dl *)s)
79
80 struct dadq;
81 static struct dadq *nd6_dad_find(struct ifaddr *, struct nd_opt_nonce *);
82 static void nd6_dad_add(struct dadq *dp);
83 static void nd6_dad_del(struct dadq *dp);
84 static void nd6_dad_rele(struct dadq *);
85 static void nd6_dad_starttimer(struct dadq *, int);
86 static void nd6_dad_stoptimer(struct dadq *);
87 static void nd6_dad_timer(void *);
88 static void nd6_dad_duplicated(struct ifaddr *, struct dadq *);
89 static void nd6_dad_ns_output(struct dadq *);
90 static void nd6_dad_ns_input(struct ifaddr *, struct nd_opt_nonce *);
91 static void nd6_dad_na_input(struct ifaddr *);
92 static void nd6_na_output_fib(struct ifnet *, const struct in6_addr *,
93 const struct in6_addr *, u_long, int, struct sockaddr *, u_int);
94 static void nd6_ns_output_fib(struct ifnet *, const struct in6_addr *,
95 const struct in6_addr *, const struct in6_addr *, uint8_t *, u_int);
96
97 VNET_DEFINE_STATIC(int, dad_enhanced) = 1;
98 #define V_dad_enhanced VNET(dad_enhanced)
99
100 SYSCTL_DECL(_net_inet6_ip6);
101 SYSCTL_INT(_net_inet6_ip6, OID_AUTO, dad_enhanced, CTLFLAG_VNET | CTLFLAG_RW,
102 &VNET_NAME(dad_enhanced), 0,
103 "Enable Enhanced DAD, which adds a random nonce to NS messages for DAD.");
104
105 VNET_DEFINE_STATIC(int, dad_maxtry) = 15; /* max # of *tries* to
106 transmit DAD packet */
107 #define V_dad_maxtry VNET(dad_maxtry)
108
109 /*
110 * Input a Neighbor Solicitation Message.
111 *
112 * Based on RFC 2461
113 * Based on RFC 2462 (duplicate address detection)
114 */
115 void
nd6_ns_input(struct mbuf * m,int off,int icmp6len)116 nd6_ns_input(struct mbuf *m, int off, int icmp6len)
117 {
118 struct ifnet *ifp;
119 struct ip6_hdr *ip6;
120 struct nd_neighbor_solicit *nd_ns;
121 struct in6_addr daddr6, myaddr6, saddr6, taddr6;
122 struct ifaddr *ifa;
123 struct sockaddr_dl proxydl;
124 union nd_opts ndopts;
125 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
126 char *lladdr;
127 int anycast, lladdrlen, proxy, rflag, tentative, tlladdr;
128
129 ifa = NULL;
130
131 /* RFC 6980: Nodes MUST silently ignore fragments */
132 if(m->m_flags & M_FRAGMENTED)
133 goto freeit;
134
135 ifp = m->m_pkthdr.rcvif;
136 ip6 = mtod(m, struct ip6_hdr *);
137 if (__predict_false(ip6->ip6_hlim != 255)) {
138 ICMP6STAT_INC(icp6s_invlhlim);
139 nd6log((LOG_ERR,
140 "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
141 ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
142 ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
143 goto bads;
144 }
145
146 if (m->m_len < off + icmp6len) {
147 m = m_pullup(m, off + icmp6len);
148 if (m == NULL) {
149 IP6STAT_INC(ip6s_exthdrtoolong);
150 return;
151 }
152 }
153 ip6 = mtod(m, struct ip6_hdr *);
154 nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
155
156 saddr6 = ip6->ip6_src;
157 daddr6 = ip6->ip6_dst;
158 taddr6 = nd_ns->nd_ns_target;
159 if (in6_setscope(&taddr6, ifp, NULL) != 0)
160 goto bad;
161
162 rflag = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
163 if (ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV && V_ip6_norbit_raif)
164 rflag = 0;
165
166 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
167 /* dst has to be a solicited node multicast address. */
168 if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
169 /* don't check ifindex portion */
170 daddr6.s6_addr32[1] == 0 &&
171 daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
172 daddr6.s6_addr8[12] == 0xff) {
173 ; /* good */
174 } else {
175 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
176 "(wrong ip6 dst)\n"));
177 goto bad;
178 }
179 } else if (!V_nd6_onlink_ns_rfc4861) {
180 struct sockaddr_in6 src_sa6;
181
182 /*
183 * According to recent IETF discussions, it is not a good idea
184 * to accept a NS from an address which would not be deemed
185 * to be a neighbor otherwise. This point is expected to be
186 * clarified in future revisions of the specification.
187 */
188 bzero(&src_sa6, sizeof(src_sa6));
189 src_sa6.sin6_family = AF_INET6;
190 src_sa6.sin6_len = sizeof(src_sa6);
191 src_sa6.sin6_addr = saddr6;
192 if (nd6_is_addr_neighbor(&src_sa6, ifp) == 0) {
193 nd6log((LOG_INFO, "nd6_ns_input: "
194 "NS packet from non-neighbor\n"));
195 goto bad;
196 }
197 }
198
199 if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
200 nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
201 goto bad;
202 }
203
204 icmp6len -= sizeof(*nd_ns);
205 nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
206 if (nd6_options(&ndopts) < 0) {
207 nd6log((LOG_INFO,
208 "nd6_ns_input: invalid ND option, ignored\n"));
209 /* nd6_options have incremented stats */
210 goto freeit;
211 }
212
213 lladdr = NULL;
214 lladdrlen = 0;
215 if (ndopts.nd_opts_src_lladdr) {
216 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
217 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
218 }
219
220 if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
221 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
222 "(link-layer address option)\n"));
223 goto bad;
224 }
225
226 /*
227 * Attaching target link-layer address to the NA?
228 * (RFC 2461 7.2.4)
229 *
230 * NS IP dst is unicast/anycast MUST NOT add
231 * NS IP dst is solicited-node multicast MUST add
232 *
233 * In implementation, we add target link-layer address by default.
234 * We do not add one in MUST NOT cases.
235 */
236 if (!IN6_IS_ADDR_MULTICAST(&daddr6))
237 tlladdr = 0;
238 else
239 tlladdr = 1;
240
241 /*
242 * Target address (taddr6) must be either:
243 * (1) Valid unicast/anycast address for my receiving interface,
244 * (2) Unicast address for which I'm offering proxy service, or
245 * (3) "tentative" address on which DAD is being performed.
246 */
247 /* (1) and (3) check. */
248 if (ifp->if_carp)
249 ifa = (*carp_iamatch6_p)(ifp, &taddr6);
250 else
251 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
252
253 /* (2) check. */
254 proxy = 0;
255 if (ifa == NULL) {
256 struct sockaddr_dl rt_gateway;
257 struct rt_addrinfo info;
258 struct sockaddr_in6 dst6;
259
260 bzero(&dst6, sizeof(dst6));
261 dst6.sin6_len = sizeof(struct sockaddr_in6);
262 dst6.sin6_family = AF_INET6;
263 dst6.sin6_addr = taddr6;
264
265 bzero(&rt_gateway, sizeof(rt_gateway));
266 rt_gateway.sdl_len = sizeof(rt_gateway);
267 bzero(&info, sizeof(info));
268 info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&rt_gateway;
269
270 if (rib_lookup_info(ifp->if_fib, (struct sockaddr *)&dst6,
271 0, 0, &info) == 0) {
272 if ((info.rti_flags & RTF_ANNOUNCE) != 0 &&
273 rt_gateway.sdl_family == AF_LINK) {
274 /*
275 * proxy NDP for single entry
276 */
277 proxydl = *SDL(&rt_gateway);
278 ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(
279 ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
280 if (ifa)
281 proxy = 1;
282 }
283 }
284 }
285 if (ifa == NULL) {
286 /*
287 * We've got an NS packet, and we don't have that address
288 * assigned for us. We MUST silently ignore it.
289 * See RFC2461 7.2.3.
290 */
291 goto freeit;
292 }
293 myaddr6 = *IFA_IN6(ifa);
294 anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
295 tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
296 if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
297 goto freeit;
298
299 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
300 nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
301 "(if %d, NS packet %d)\n",
302 ip6_sprintf(ip6bufs, &taddr6),
303 ifp->if_addrlen, lladdrlen - 2));
304 goto bad;
305 }
306
307 if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
308 nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
309 ip6_sprintf(ip6bufs, &saddr6)));
310 goto freeit;
311 }
312
313 /*
314 * We have neighbor solicitation packet, with target address equals to
315 * one of my tentative address.
316 *
317 * src addr how to process?
318 * --- ---
319 * multicast of course, invalid (rejected in ip6_input)
320 * unicast somebody is doing address resolution -> ignore
321 * unspec dup address detection
322 *
323 * The processing is defined in RFC 2462.
324 */
325 if (tentative) {
326 /*
327 * If source address is unspecified address, it is for
328 * duplicate address detection.
329 *
330 * If not, the packet is for addess resolution;
331 * silently ignore it.
332 */
333 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
334 nd6_dad_ns_input(ifa, ndopts.nd_opts_nonce);
335
336 goto freeit;
337 }
338
339 /*
340 * If the source address is unspecified address, entries must not
341 * be created or updated.
342 * It looks that sender is performing DAD. Output NA toward
343 * all-node multicast address, to tell the sender that I'm using
344 * the address.
345 * S bit ("solicited") must be zero.
346 */
347 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
348 struct in6_addr in6_all;
349
350 in6_all = in6addr_linklocal_allnodes;
351 if (in6_setscope(&in6_all, ifp, NULL) != 0)
352 goto bad;
353 nd6_na_output_fib(ifp, &in6_all, &taddr6,
354 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
355 rflag, tlladdr, proxy ? (struct sockaddr *)&proxydl : NULL,
356 M_GETFIB(m));
357 goto freeit;
358 }
359
360 nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen,
361 ND_NEIGHBOR_SOLICIT, 0);
362
363 nd6_na_output_fib(ifp, &saddr6, &taddr6,
364 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
365 rflag | ND_NA_FLAG_SOLICITED, tlladdr,
366 proxy ? (struct sockaddr *)&proxydl : NULL, M_GETFIB(m));
367 freeit:
368 if (ifa != NULL)
369 ifa_free(ifa);
370 m_freem(m);
371 return;
372
373 bad:
374 nd6log((LOG_ERR, "nd6_ns_input: src=%s\n",
375 ip6_sprintf(ip6bufs, &saddr6)));
376 nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n",
377 ip6_sprintf(ip6bufs, &daddr6)));
378 nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n",
379 ip6_sprintf(ip6bufs, &taddr6)));
380 bads:
381 ICMP6STAT_INC(icp6s_badns);
382 if (ifa != NULL)
383 ifa_free(ifa);
384 m_freem(m);
385 }
386
387 /*
388 * Output a Neighbor Solicitation Message. Caller specifies:
389 * - ICMP6 header source IP6 address
390 * - ND6 header target IP6 address
391 * - ND6 header source datalink address
392 *
393 * Based on RFC 2461
394 * Based on RFC 2462 (duplicate address detection)
395 *
396 * ln - for source address determination
397 * nonce - If non-NULL, NS is used for duplicate address detection and
398 * the value (length is ND_OPT_NONCE_LEN) is used as a random nonce.
399 */
400 static void
nd6_ns_output_fib(struct ifnet * ifp,const struct in6_addr * saddr6,const struct in6_addr * daddr6,const struct in6_addr * taddr6,uint8_t * nonce,u_int fibnum)401 nd6_ns_output_fib(struct ifnet *ifp, const struct in6_addr *saddr6,
402 const struct in6_addr *daddr6, const struct in6_addr *taddr6,
403 uint8_t *nonce, u_int fibnum)
404 {
405 struct mbuf *m;
406 struct m_tag *mtag;
407 struct ip6_hdr *ip6;
408 struct nd_neighbor_solicit *nd_ns;
409 struct ip6_moptions im6o;
410 int icmp6len;
411 int maxlen;
412
413 NET_EPOCH_ASSERT();
414
415 if (IN6_IS_ADDR_MULTICAST(taddr6))
416 return;
417
418 /* estimate the size of message */
419 maxlen = sizeof(*ip6) + sizeof(*nd_ns);
420 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
421 KASSERT(max_linkhdr + maxlen <= MCLBYTES, (
422 "%s: max_linkhdr + maxlen > MCLBYTES (%d + %d > %d)",
423 __func__, max_linkhdr, maxlen, MCLBYTES));
424
425 if (max_linkhdr + maxlen > MHLEN)
426 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
427 else
428 m = m_gethdr(M_NOWAIT, MT_DATA);
429 if (m == NULL)
430 return;
431 M_SETFIB(m, fibnum);
432
433 if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
434 m->m_flags |= M_MCAST;
435 im6o.im6o_multicast_ifp = ifp;
436 im6o.im6o_multicast_hlim = 255;
437 im6o.im6o_multicast_loop = 0;
438 }
439
440 icmp6len = sizeof(*nd_ns);
441 m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
442 m->m_data += max_linkhdr; /* or M_ALIGN() equivalent? */
443
444 /* fill neighbor solicitation packet */
445 ip6 = mtod(m, struct ip6_hdr *);
446 ip6->ip6_flow = 0;
447 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
448 ip6->ip6_vfc |= IPV6_VERSION;
449 /* ip6->ip6_plen will be set later */
450 ip6->ip6_nxt = IPPROTO_ICMPV6;
451 ip6->ip6_hlim = 255;
452 if (daddr6)
453 ip6->ip6_dst = *daddr6;
454 else {
455 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
456 ip6->ip6_dst.s6_addr16[1] = 0;
457 ip6->ip6_dst.s6_addr32[1] = 0;
458 ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
459 ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
460 ip6->ip6_dst.s6_addr8[12] = 0xff;
461 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
462 goto bad;
463 }
464 if (nonce == NULL) {
465 struct ifaddr *ifa = NULL;
466
467 /*
468 * RFC2461 7.2.2:
469 * "If the source address of the packet prompting the
470 * solicitation is the same as one of the addresses assigned
471 * to the outgoing interface, that address SHOULD be placed
472 * in the IP Source Address of the outgoing solicitation.
473 * Otherwise, any one of the addresses assigned to the
474 * interface should be used."
475 *
476 * We use the source address for the prompting packet
477 * (saddr6), if saddr6 belongs to the outgoing interface.
478 * Otherwise, we perform the source address selection as usual.
479 */
480
481 if (saddr6 != NULL)
482 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, saddr6);
483 if (ifa != NULL) {
484 /* ip6_src set already. */
485 ip6->ip6_src = *saddr6;
486 ifa_free(ifa);
487 } else {
488 int error;
489 struct in6_addr dst6, src6;
490 uint32_t scopeid;
491
492 in6_splitscope(&ip6->ip6_dst, &dst6, &scopeid);
493 error = in6_selectsrc_addr(fibnum, &dst6,
494 scopeid, ifp, &src6, NULL);
495 if (error) {
496 char ip6buf[INET6_ADDRSTRLEN];
497 nd6log((LOG_DEBUG, "%s: source can't be "
498 "determined: dst=%s, error=%d\n", __func__,
499 ip6_sprintf(ip6buf, &dst6),
500 error));
501 goto bad;
502 }
503 ip6->ip6_src = src6;
504 }
505 } else {
506 /*
507 * Source address for DAD packet must always be IPv6
508 * unspecified address. (0::0)
509 * We actually don't have to 0-clear the address (we did it
510 * above), but we do so here explicitly to make the intention
511 * clearer.
512 */
513 bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
514 }
515 nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
516 nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
517 nd_ns->nd_ns_code = 0;
518 nd_ns->nd_ns_reserved = 0;
519 nd_ns->nd_ns_target = *taddr6;
520 in6_clearscope(&nd_ns->nd_ns_target); /* XXX */
521
522 /*
523 * Add source link-layer address option.
524 *
525 * spec implementation
526 * --- ---
527 * DAD packet MUST NOT do not add the option
528 * there's no link layer address:
529 * impossible do not add the option
530 * there's link layer address:
531 * Multicast NS MUST add one add the option
532 * Unicast NS SHOULD add one add the option
533 */
534 if (nonce == NULL) {
535 struct nd_opt_hdr *nd_opt;
536 char *mac;
537 int optlen;
538
539 mac = NULL;
540 if (ifp->if_carp)
541 mac = (*carp_macmatch6_p)(ifp, m, &ip6->ip6_src);
542 if (mac == NULL)
543 mac = nd6_ifptomac(ifp);
544
545 if (mac != NULL) {
546 nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
547 optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
548 /* 8 byte alignments... */
549 optlen = (optlen + 7) & ~7;
550 m->m_pkthdr.len += optlen;
551 m->m_len += optlen;
552 icmp6len += optlen;
553 bzero(nd_opt, optlen);
554 nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
555 nd_opt->nd_opt_len = optlen >> 3;
556 bcopy(mac, nd_opt + 1, ifp->if_addrlen);
557 }
558 }
559 /*
560 * Add a Nonce option (RFC 3971) to detect looped back NS messages.
561 * This behavior is documented as Enhanced Duplicate Address
562 * Detection in RFC 7527.
563 * net.inet6.ip6.dad_enhanced=0 disables this.
564 */
565 if (V_dad_enhanced != 0 && nonce != NULL) {
566 int optlen = sizeof(struct nd_opt_hdr) + ND_OPT_NONCE_LEN;
567 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
568 /* 8-byte alignment is required. */
569 optlen = (optlen + 7) & ~7;
570
571 m->m_pkthdr.len += optlen;
572 m->m_len += optlen;
573 icmp6len += optlen;
574 bzero((caddr_t)nd_opt, optlen);
575 nd_opt->nd_opt_type = ND_OPT_NONCE;
576 nd_opt->nd_opt_len = optlen >> 3;
577 bcopy(nonce, (caddr_t)(nd_opt + 1), ND_OPT_NONCE_LEN);
578 }
579 ip6->ip6_plen = htons((u_short)icmp6len);
580 nd_ns->nd_ns_cksum = 0;
581 nd_ns->nd_ns_cksum =
582 in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
583
584 if (send_sendso_input_hook != NULL) {
585 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
586 sizeof(unsigned short), M_NOWAIT);
587 if (mtag == NULL)
588 goto bad;
589 *(unsigned short *)(mtag + 1) = nd_ns->nd_ns_type;
590 m_tag_prepend(m, mtag);
591 }
592
593 ip6_output(m, NULL, NULL, (nonce != NULL) ? IPV6_UNSPECSRC : 0,
594 &im6o, NULL, NULL);
595 icmp6_ifstat_inc(ifp, ifs6_out_msg);
596 icmp6_ifstat_inc(ifp, ifs6_out_neighborsolicit);
597 ICMP6STAT_INC(icp6s_outhist[ND_NEIGHBOR_SOLICIT]);
598
599 return;
600
601 bad:
602 m_freem(m);
603 }
604
605 #ifndef BURN_BRIDGES
606 void
nd6_ns_output(struct ifnet * ifp,const struct in6_addr * saddr6,const struct in6_addr * daddr6,const struct in6_addr * taddr6,uint8_t * nonce)607 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *saddr6,
608 const struct in6_addr *daddr6, const struct in6_addr *taddr6,uint8_t *nonce)
609 {
610
611 nd6_ns_output_fib(ifp, saddr6, daddr6, taddr6, nonce, RT_DEFAULT_FIB);
612 }
613 #endif
614 /*
615 * Neighbor advertisement input handling.
616 *
617 * Based on RFC 2461
618 * Based on RFC 2462 (duplicate address detection)
619 *
620 * the following items are not implemented yet:
621 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
622 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
623 */
624 void
nd6_na_input(struct mbuf * m,int off,int icmp6len)625 nd6_na_input(struct mbuf *m, int off, int icmp6len)
626 {
627 struct ifnet *ifp;
628 struct ip6_hdr *ip6;
629 struct ifaddr *ifa;
630 struct llentry *ln;
631 struct mbuf *chain;
632 struct nd_neighbor_advert *nd_na;
633 struct in6_addr daddr6, taddr6;
634 union nd_opts ndopts;
635 u_char linkhdr[LLE_MAX_LINKHDR];
636 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
637 char *lladdr;
638 size_t linkhdrsize;
639 int flags, is_override, is_router, is_solicited;
640 int lladdr_off, lladdrlen, checklink;
641 bool flush_holdchain = false;
642
643 NET_EPOCH_ASSERT();
644
645 chain = NULL;
646 ln = NULL;
647 checklink = 0;
648
649 /* RFC 6980: Nodes MUST silently ignore fragments */
650 if(m->m_flags & M_FRAGMENTED)
651 goto freeit;
652
653 ifp = m->m_pkthdr.rcvif;
654 ip6 = mtod(m, struct ip6_hdr *);
655 if (__predict_false(ip6->ip6_hlim != 255)) {
656 ICMP6STAT_INC(icp6s_invlhlim);
657 nd6log((LOG_ERR,
658 "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
659 ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
660 ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
661 goto bad;
662 }
663
664 if (m->m_len < off + icmp6len) {
665 m = m_pullup(m, off + icmp6len);
666 if (m == NULL) {
667 IP6STAT_INC(ip6s_exthdrtoolong);
668 return;
669 }
670 }
671 ip6 = mtod(m, struct ip6_hdr *);
672 nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
673
674 flags = nd_na->nd_na_flags_reserved;
675 is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
676 is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
677 is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
678
679 taddr6 = nd_na->nd_na_target;
680 if (in6_setscope(&taddr6, ifp, NULL))
681 goto bad; /* XXX: impossible */
682
683 if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
684 nd6log((LOG_ERR,
685 "nd6_na_input: invalid target address %s\n",
686 ip6_sprintf(ip6bufs, &taddr6)));
687 goto bad;
688 }
689
690 daddr6 = ip6->ip6_dst;
691 if (IN6_IS_ADDR_MULTICAST(&daddr6))
692 if (is_solicited) {
693 nd6log((LOG_ERR,
694 "nd6_na_input: a solicited adv is multicasted\n"));
695 goto bad;
696 }
697
698 icmp6len -= sizeof(*nd_na);
699 nd6_option_init(nd_na + 1, icmp6len, &ndopts);
700 if (nd6_options(&ndopts) < 0) {
701 nd6log((LOG_INFO,
702 "nd6_na_input: invalid ND option, ignored\n"));
703 /* nd6_options have incremented stats */
704 goto freeit;
705 }
706
707 lladdr = NULL;
708 lladdrlen = 0;
709 if (ndopts.nd_opts_tgt_lladdr) {
710 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
711 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
712 }
713
714 /*
715 * This effectively disables the DAD check on a non-master CARP
716 * address.
717 */
718 if (ifp->if_carp)
719 ifa = (*carp_iamatch6_p)(ifp, &taddr6);
720 else
721 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
722
723 /*
724 * Target address matches one of my interface address.
725 *
726 * If my address is tentative, this means that there's somebody
727 * already using the same address as mine. This indicates DAD failure.
728 * This is defined in RFC 2462.
729 *
730 * Otherwise, process as defined in RFC 2461.
731 */
732 if (ifa
733 && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
734 nd6_dad_na_input(ifa);
735 ifa_free(ifa);
736 goto freeit;
737 }
738
739 /* Just for safety, maybe unnecessary. */
740 if (ifa) {
741 ifa_free(ifa);
742 log(LOG_ERR,
743 "nd6_na_input: duplicate IP6 address %s\n",
744 ip6_sprintf(ip6bufs, &taddr6));
745 goto freeit;
746 }
747
748 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
749 nd6log((LOG_INFO, "nd6_na_input: lladdrlen mismatch for %s "
750 "(if %d, NA packet %d)\n", ip6_sprintf(ip6bufs, &taddr6),
751 ifp->if_addrlen, lladdrlen - 2));
752 goto bad;
753 }
754
755 /*
756 * If no neighbor cache entry is found, NA SHOULD silently be
757 * discarded.
758 */
759 ln = nd6_lookup(&taddr6, LLE_SF(AF_INET6, LLE_EXCLUSIVE), ifp);
760 if (ln == NULL) {
761 goto freeit;
762 }
763
764 /*
765 * Do not try to override static entry.
766 */
767 if (ln->la_flags & LLE_STATIC)
768 goto freeit;
769
770 if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
771 /*
772 * If the link-layer has address, and no lladdr option came,
773 * discard the packet.
774 */
775 if (ifp->if_addrlen && lladdr == NULL) {
776 goto freeit;
777 }
778
779 /*
780 * Record link-layer address, and update the state.
781 */
782 if (!nd6_try_set_entry_addr(ifp, ln, lladdr))
783 goto freeit;
784
785 flush_holdchain = true;
786 if (is_solicited)
787 nd6_llinfo_setstate(ln, ND6_LLINFO_REACHABLE);
788 else
789 nd6_llinfo_setstate(ln, ND6_LLINFO_STALE);
790 EVENTHANDLER_INVOKE(lle_event, ln, LLENTRY_RESOLVED);
791 if ((ln->ln_router = is_router) != 0) {
792 /*
793 * This means a router's state has changed from
794 * non-reachable to probably reachable, and might
795 * affect the status of associated prefixes..
796 */
797 checklink = 1;
798 }
799 } else {
800 int llchange;
801
802 /*
803 * Check if the link-layer address has changed or not.
804 */
805 if (lladdr == NULL)
806 llchange = 0;
807 else {
808 if (ln->la_flags & LLE_VALID) {
809 if (bcmp(lladdr, ln->ll_addr, ifp->if_addrlen))
810 llchange = 1;
811 else
812 llchange = 0;
813 } else
814 llchange = 1;
815 }
816
817 /*
818 * This is VERY complex. Look at it with care.
819 *
820 * override solicit lladdr llchange action
821 * (L: record lladdr)
822 *
823 * 0 0 n -- (2c)
824 * 0 0 y n (2b) L
825 * 0 0 y y (1) REACHABLE->STALE
826 * 0 1 n -- (2c) *->REACHABLE
827 * 0 1 y n (2b) L *->REACHABLE
828 * 0 1 y y (1) REACHABLE->STALE
829 * 1 0 n -- (2a)
830 * 1 0 y n (2a) L
831 * 1 0 y y (2a) L *->STALE
832 * 1 1 n -- (2a) *->REACHABLE
833 * 1 1 y n (2a) L *->REACHABLE
834 * 1 1 y y (2a) L *->REACHABLE
835 */
836 if (!is_override && (lladdr != NULL && llchange)) { /* (1) */
837 /*
838 * If state is REACHABLE, make it STALE.
839 * no other updates should be done.
840 */
841 if (ln->ln_state == ND6_LLINFO_REACHABLE)
842 nd6_llinfo_setstate(ln, ND6_LLINFO_STALE);
843 goto freeit;
844 } else if (is_override /* (2a) */
845 || (!is_override && (lladdr != NULL && !llchange)) /* (2b) */
846 || lladdr == NULL) { /* (2c) */
847 /*
848 * Update link-local address, if any.
849 */
850 if (lladdr != NULL) {
851 linkhdrsize = sizeof(linkhdr);
852 if (lltable_calc_llheader(ifp, AF_INET6, lladdr,
853 linkhdr, &linkhdrsize, &lladdr_off) != 0)
854 goto freeit;
855 if (lltable_try_set_entry_addr(ifp, ln, linkhdr,
856 linkhdrsize, lladdr_off) == 0)
857 goto freeit;
858 EVENTHANDLER_INVOKE(lle_event, ln,
859 LLENTRY_RESOLVED);
860 }
861
862 /*
863 * If solicited, make the state REACHABLE.
864 * If not solicited and the link-layer address was
865 * changed, make it STALE.
866 */
867 if (is_solicited)
868 nd6_llinfo_setstate(ln, ND6_LLINFO_REACHABLE);
869 else {
870 if (lladdr != NULL && llchange)
871 nd6_llinfo_setstate(ln, ND6_LLINFO_STALE);
872 }
873 }
874
875 if (ln->ln_router && !is_router) {
876 /*
877 * The peer dropped the router flag.
878 * Remove the sender from the Default Router List and
879 * update the Destination Cache entries.
880 */
881 struct ifnet *nd6_ifp;
882
883 nd6_ifp = lltable_get_ifp(ln->lle_tbl);
884 if (!defrouter_remove(&ln->r_l3addr.addr6, nd6_ifp) &&
885 (ND_IFINFO(nd6_ifp)->flags &
886 ND6_IFF_ACCEPT_RTADV) != 0)
887 /*
888 * Even if the neighbor is not in the default
889 * router list, the neighbor may be used as a
890 * next hop for some destinations (e.g. redirect
891 * case). So we must call rt6_flush explicitly.
892 */
893 rt6_flush(&ip6->ip6_src, ifp);
894 }
895 ln->ln_router = is_router;
896 }
897 /* XXX - QL
898 * Does this matter?
899 * rt->rt_flags &= ~RTF_REJECT;
900 */
901 ln->la_asked = 0;
902 if (ln->la_hold != NULL)
903 chain = nd6_grab_holdchain(ln);
904 freeit:
905 if (ln != NULL)
906 LLE_WUNLOCK(ln);
907
908 if (chain != NULL)
909 nd6_flush_holdchain(ifp, ln, chain);
910 if (flush_holdchain)
911 nd6_flush_children_holdchain(ifp, ln);
912
913 if (checklink)
914 pfxlist_onlink_check();
915
916 m_freem(m);
917 return;
918
919 bad:
920 if (ln != NULL)
921 LLE_WUNLOCK(ln);
922
923 ICMP6STAT_INC(icp6s_badna);
924 m_freem(m);
925 }
926
927 /*
928 * Neighbor advertisement output handling.
929 *
930 * Based on RFC 2461
931 *
932 * the following items are not implemented yet:
933 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
934 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
935 *
936 * tlladdr - 1 if include target link-layer address
937 * sdl0 - sockaddr_dl (= proxy NA) or NULL
938 */
939 static void
nd6_na_output_fib(struct ifnet * ifp,const struct in6_addr * daddr6_0,const struct in6_addr * taddr6,u_long flags,int tlladdr,struct sockaddr * sdl0,u_int fibnum)940 nd6_na_output_fib(struct ifnet *ifp, const struct in6_addr *daddr6_0,
941 const struct in6_addr *taddr6, u_long flags, int tlladdr,
942 struct sockaddr *sdl0, u_int fibnum)
943 {
944 struct mbuf *m;
945 struct m_tag *mtag;
946 struct ip6_hdr *ip6;
947 struct nd_neighbor_advert *nd_na;
948 struct ip6_moptions im6o;
949 struct in6_addr daddr6, dst6, src6;
950 uint32_t scopeid;
951
952 NET_EPOCH_ASSERT();
953
954 int icmp6len, maxlen, error;
955 caddr_t mac = NULL;
956
957 daddr6 = *daddr6_0; /* make a local copy for modification */
958
959 /* estimate the size of message */
960 maxlen = sizeof(*ip6) + sizeof(*nd_na);
961 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
962 KASSERT(max_linkhdr + maxlen <= MCLBYTES, (
963 "%s: max_linkhdr + maxlen > MCLBYTES (%d + %d > %d)",
964 __func__, max_linkhdr, maxlen, MCLBYTES));
965
966 if (max_linkhdr + maxlen > MHLEN)
967 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
968 else
969 m = m_gethdr(M_NOWAIT, MT_DATA);
970 if (m == NULL)
971 return;
972 M_SETFIB(m, fibnum);
973
974 if (IN6_IS_ADDR_MULTICAST(&daddr6)) {
975 m->m_flags |= M_MCAST;
976 im6o.im6o_multicast_ifp = ifp;
977 im6o.im6o_multicast_hlim = 255;
978 im6o.im6o_multicast_loop = 0;
979 }
980
981 icmp6len = sizeof(*nd_na);
982 m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
983 m->m_data += max_linkhdr; /* or M_ALIGN() equivalent? */
984
985 /* fill neighbor advertisement packet */
986 ip6 = mtod(m, struct ip6_hdr *);
987 ip6->ip6_flow = 0;
988 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
989 ip6->ip6_vfc |= IPV6_VERSION;
990 ip6->ip6_nxt = IPPROTO_ICMPV6;
991 ip6->ip6_hlim = 255;
992 if (IN6_IS_ADDR_UNSPECIFIED(&daddr6)) {
993 /* reply to DAD */
994 daddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
995 daddr6.s6_addr16[1] = 0;
996 daddr6.s6_addr32[1] = 0;
997 daddr6.s6_addr32[2] = 0;
998 daddr6.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
999 if (in6_setscope(&daddr6, ifp, NULL))
1000 goto bad;
1001
1002 flags &= ~ND_NA_FLAG_SOLICITED;
1003 }
1004 ip6->ip6_dst = daddr6;
1005
1006 /*
1007 * Select a source whose scope is the same as that of the dest.
1008 */
1009 in6_splitscope(&daddr6, &dst6, &scopeid);
1010 error = in6_selectsrc_addr(fibnum, &dst6,
1011 scopeid, ifp, &src6, NULL);
1012 if (error) {
1013 char ip6buf[INET6_ADDRSTRLEN];
1014 nd6log((LOG_DEBUG, "nd6_na_output: source can't be "
1015 "determined: dst=%s, error=%d\n",
1016 ip6_sprintf(ip6buf, &daddr6), error));
1017 goto bad;
1018 }
1019 ip6->ip6_src = src6;
1020 nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
1021 nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
1022 nd_na->nd_na_code = 0;
1023 nd_na->nd_na_target = *taddr6;
1024 in6_clearscope(&nd_na->nd_na_target); /* XXX */
1025
1026 /*
1027 * "tlladdr" indicates NS's condition for adding tlladdr or not.
1028 * see nd6_ns_input() for details.
1029 * Basically, if NS packet is sent to unicast/anycast addr,
1030 * target lladdr option SHOULD NOT be included.
1031 */
1032 if (tlladdr) {
1033 /*
1034 * sdl0 != NULL indicates proxy NA. If we do proxy, use
1035 * lladdr in sdl0. If we are not proxying (sending NA for
1036 * my address) use lladdr configured for the interface.
1037 */
1038 if (sdl0 == NULL) {
1039 if (ifp->if_carp)
1040 mac = (*carp_macmatch6_p)(ifp, m, taddr6);
1041 if (mac == NULL)
1042 mac = nd6_ifptomac(ifp);
1043 } else if (sdl0->sa_family == AF_LINK) {
1044 struct sockaddr_dl *sdl;
1045 sdl = (struct sockaddr_dl *)sdl0;
1046 if (sdl->sdl_alen == ifp->if_addrlen)
1047 mac = LLADDR(sdl);
1048 }
1049 }
1050 if (tlladdr && mac) {
1051 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
1052 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
1053
1054 /* roundup to 8 bytes alignment! */
1055 optlen = (optlen + 7) & ~7;
1056
1057 m->m_pkthdr.len += optlen;
1058 m->m_len += optlen;
1059 icmp6len += optlen;
1060 bzero((caddr_t)nd_opt, optlen);
1061 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
1062 nd_opt->nd_opt_len = optlen >> 3;
1063 bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
1064 } else
1065 flags &= ~ND_NA_FLAG_OVERRIDE;
1066
1067 ip6->ip6_plen = htons((u_short)icmp6len);
1068 nd_na->nd_na_flags_reserved = flags;
1069 nd_na->nd_na_cksum = 0;
1070 nd_na->nd_na_cksum =
1071 in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
1072
1073 if (send_sendso_input_hook != NULL) {
1074 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
1075 sizeof(unsigned short), M_NOWAIT);
1076 if (mtag == NULL)
1077 goto bad;
1078 *(unsigned short *)(mtag + 1) = nd_na->nd_na_type;
1079 m_tag_prepend(m, mtag);
1080 }
1081
1082 ip6_output(m, NULL, NULL, 0, &im6o, NULL, NULL);
1083 icmp6_ifstat_inc(ifp, ifs6_out_msg);
1084 icmp6_ifstat_inc(ifp, ifs6_out_neighboradvert);
1085 ICMP6STAT_INC(icp6s_outhist[ND_NEIGHBOR_ADVERT]);
1086
1087 return;
1088
1089 bad:
1090 m_freem(m);
1091 }
1092
1093 #ifndef BURN_BRIDGES
1094 void
nd6_na_output(struct ifnet * ifp,const struct in6_addr * daddr6_0,const struct in6_addr * taddr6,u_long flags,int tlladdr,struct sockaddr * sdl0)1095 nd6_na_output(struct ifnet *ifp, const struct in6_addr *daddr6_0,
1096 const struct in6_addr *taddr6, u_long flags, int tlladdr,
1097 struct sockaddr *sdl0)
1098 {
1099
1100 nd6_na_output_fib(ifp, daddr6_0, taddr6, flags, tlladdr, sdl0,
1101 RT_DEFAULT_FIB);
1102 }
1103 #endif
1104
1105 caddr_t
nd6_ifptomac(struct ifnet * ifp)1106 nd6_ifptomac(struct ifnet *ifp)
1107 {
1108 switch (ifp->if_type) {
1109 case IFT_ETHER:
1110 case IFT_IEEE1394:
1111 case IFT_L2VLAN:
1112 case IFT_INFINIBAND:
1113 case IFT_BRIDGE:
1114 return IF_LLADDR(ifp);
1115 default:
1116 return NULL;
1117 }
1118 }
1119
1120 struct dadq {
1121 TAILQ_ENTRY(dadq) dad_list;
1122 struct ifaddr *dad_ifa;
1123 int dad_count; /* max NS to send */
1124 int dad_ns_tcount; /* # of trials to send NS */
1125 int dad_ns_ocount; /* NS sent so far */
1126 int dad_ns_icount;
1127 int dad_na_icount;
1128 int dad_ns_lcount; /* looped back NS */
1129 int dad_loopbackprobe; /* probing state for loopback detection */
1130 struct callout dad_timer_ch;
1131 struct vnet *dad_vnet;
1132 u_int dad_refcnt;
1133 #define ND_OPT_NONCE_LEN32 \
1134 ((ND_OPT_NONCE_LEN + sizeof(uint32_t) - 1)/sizeof(uint32_t))
1135 uint32_t dad_nonce[ND_OPT_NONCE_LEN32];
1136 bool dad_ondadq; /* on dadq? Protected by DADQ_WLOCK. */
1137 };
1138
1139 VNET_DEFINE_STATIC(TAILQ_HEAD(, dadq), dadq);
1140 VNET_DEFINE_STATIC(struct rwlock, dad_rwlock);
1141 #define V_dadq VNET(dadq)
1142 #define V_dad_rwlock VNET(dad_rwlock)
1143
1144 #define DADQ_LOCKPTR() (&V_dad_rwlock)
1145 #define DADQ_LOCK_INIT() rw_init(DADQ_LOCKPTR(), "nd6 DAD queue")
1146 #define DADQ_RLOCK() rw_rlock(DADQ_LOCKPTR())
1147 #define DADQ_RUNLOCK() rw_runlock(DADQ_LOCKPTR())
1148 #define DADQ_WLOCK() rw_wlock(DADQ_LOCKPTR())
1149 #define DADQ_WUNLOCK() rw_wunlock(DADQ_LOCKPTR())
1150
1151 #define DADQ_LOCK_ASSERT() rw_assert(DADQ_LOCKPTR(), RA_LOCKED);
1152 #define DADQ_RLOCK_ASSERT() rw_assert(DADQ_LOCKPTR(), RA_RLOCKED);
1153 #define DADQ_WLOCK_ASSERT() rw_assert(DADQ_LOCKPTR(), RA_WLOCKED);
1154
1155 static void
nd6_dad_add(struct dadq * dp)1156 nd6_dad_add(struct dadq *dp)
1157 {
1158 DADQ_WLOCK_ASSERT();
1159
1160 TAILQ_INSERT_TAIL(&V_dadq, dp, dad_list);
1161 dp->dad_ondadq = true;
1162 }
1163
1164 static void
nd6_dad_del(struct dadq * dp)1165 nd6_dad_del(struct dadq *dp)
1166 {
1167 DADQ_WLOCK_ASSERT();
1168
1169 if (dp->dad_ondadq) {
1170 /*
1171 * Remove dp from the dadq and release the dadq's
1172 * reference.
1173 */
1174 TAILQ_REMOVE(&V_dadq, dp, dad_list);
1175 dp->dad_ondadq = false;
1176 nd6_dad_rele(dp);
1177 }
1178 }
1179
1180 static struct dadq *
nd6_dad_find(struct ifaddr * ifa,struct nd_opt_nonce * n)1181 nd6_dad_find(struct ifaddr *ifa, struct nd_opt_nonce *n)
1182 {
1183 struct dadq *dp;
1184
1185 DADQ_LOCK_ASSERT();
1186
1187 TAILQ_FOREACH(dp, &V_dadq, dad_list) {
1188 if (dp->dad_ifa != ifa)
1189 continue;
1190
1191 /*
1192 * Skip if the nonce matches the received one.
1193 * +2 in the length is required because of type and
1194 * length fields are included in a header.
1195 */
1196 if (n != NULL &&
1197 n->nd_opt_nonce_len == (ND_OPT_NONCE_LEN + 2) / 8 &&
1198 memcmp(&n->nd_opt_nonce[0], &dp->dad_nonce[0],
1199 ND_OPT_NONCE_LEN) == 0) {
1200 dp->dad_ns_lcount++;
1201 continue;
1202 }
1203 break;
1204 }
1205
1206 return (dp);
1207 }
1208
1209 static void
nd6_dad_starttimer(struct dadq * dp,int ticks)1210 nd6_dad_starttimer(struct dadq *dp, int ticks)
1211 {
1212 DADQ_WLOCK_ASSERT();
1213
1214 callout_reset(&dp->dad_timer_ch, ticks, nd6_dad_timer, dp);
1215 }
1216
1217 static void
nd6_dad_stoptimer(struct dadq * dp)1218 nd6_dad_stoptimer(struct dadq *dp)
1219 {
1220 callout_drain(&dp->dad_timer_ch);
1221 }
1222
1223 static void
nd6_dad_rele(struct dadq * dp)1224 nd6_dad_rele(struct dadq *dp)
1225 {
1226 if (refcount_release(&dp->dad_refcnt)) {
1227 KASSERT(!dp->dad_ondadq, ("dp %p still on DAD queue", dp));
1228 ifa_free(dp->dad_ifa);
1229 free(dp, M_IP6NDP);
1230 }
1231 }
1232
1233 void
nd6_dad_init(void)1234 nd6_dad_init(void)
1235 {
1236 DADQ_LOCK_INIT();
1237 TAILQ_INIT(&V_dadq);
1238 }
1239
1240 /*
1241 * Start Duplicate Address Detection (DAD) for specified interface address.
1242 */
1243 void
nd6_dad_start(struct ifaddr * ifa,int delay)1244 nd6_dad_start(struct ifaddr *ifa, int delay)
1245 {
1246 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1247 struct dadq *dp;
1248 char ip6buf[INET6_ADDRSTRLEN];
1249
1250 KASSERT((ia->ia6_flags & IN6_IFF_TENTATIVE) != 0,
1251 ("starting DAD on non-tentative address %p", ifa));
1252
1253 /*
1254 * If we don't need DAD, don't do it.
1255 * There are several cases:
1256 * - DAD is disabled globally or on the interface
1257 * - the interface address is anycast
1258 */
1259 if ((ia->ia6_flags & IN6_IFF_ANYCAST) != 0 ||
1260 V_ip6_dad_count == 0 ||
1261 (ND_IFINFO(ifa->ifa_ifp)->flags & ND6_IFF_NO_DAD) != 0) {
1262 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1263 return;
1264 }
1265 if ((ifa->ifa_ifp->if_flags & IFF_UP) == 0 ||
1266 (ifa->ifa_ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
1267 (ND_IFINFO(ifa->ifa_ifp)->flags & ND6_IFF_IFDISABLED) != 0)
1268 return;
1269
1270 DADQ_WLOCK();
1271 if ((dp = nd6_dad_find(ifa, NULL)) != NULL) {
1272 /*
1273 * DAD is already in progress. Let the existing entry
1274 * finish it.
1275 */
1276 DADQ_WUNLOCK();
1277 return;
1278 }
1279
1280 dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT | M_ZERO);
1281 if (dp == NULL) {
1282 log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
1283 "%s(%s)\n",
1284 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
1285 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1286 return;
1287 }
1288 callout_init_rw(&dp->dad_timer_ch, DADQ_LOCKPTR(),
1289 CALLOUT_RETURNUNLOCKED);
1290 #ifdef VIMAGE
1291 dp->dad_vnet = curvnet;
1292 #endif
1293 nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
1294 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr)));
1295
1296 /*
1297 * Send NS packet for DAD, ip6_dad_count times.
1298 * Note that we must delay the first transmission, if this is the
1299 * first packet to be sent from the interface after interface
1300 * (re)initialization.
1301 */
1302 dp->dad_ifa = ifa;
1303 ifa_ref(dp->dad_ifa);
1304 dp->dad_count = V_ip6_dad_count;
1305 dp->dad_ns_icount = dp->dad_na_icount = 0;
1306 dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
1307 dp->dad_ns_lcount = dp->dad_loopbackprobe = 0;
1308
1309 /* Add this to the dadq and add a reference for the dadq. */
1310 refcount_init(&dp->dad_refcnt, 1);
1311 nd6_dad_add(dp);
1312 nd6_dad_starttimer(dp, delay);
1313 DADQ_WUNLOCK();
1314 }
1315
1316 /*
1317 * terminate DAD unconditionally. used for address removals.
1318 */
1319 void
nd6_dad_stop(struct ifaddr * ifa)1320 nd6_dad_stop(struct ifaddr *ifa)
1321 {
1322 struct dadq *dp;
1323
1324 DADQ_WLOCK();
1325 dp = nd6_dad_find(ifa, NULL);
1326 if (dp == NULL) {
1327 DADQ_WUNLOCK();
1328 /* DAD wasn't started yet */
1329 return;
1330 }
1331
1332 /*
1333 * Acquire a temporary reference so that we can safely stop the callout.
1334 */
1335 (void)refcount_acquire(&dp->dad_refcnt);
1336 nd6_dad_del(dp);
1337 DADQ_WUNLOCK();
1338
1339 nd6_dad_stoptimer(dp);
1340 nd6_dad_rele(dp);
1341 }
1342
1343 static void
nd6_dad_timer(void * arg)1344 nd6_dad_timer(void *arg)
1345 {
1346 struct dadq *dp = arg;
1347 struct ifaddr *ifa = dp->dad_ifa;
1348 struct ifnet *ifp = dp->dad_ifa->ifa_ifp;
1349 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1350 char ip6buf[INET6_ADDRSTRLEN];
1351 struct epoch_tracker et;
1352
1353 CURVNET_SET(dp->dad_vnet);
1354 KASSERT(ia != NULL, ("DAD entry %p with no address", dp));
1355
1356 NET_EPOCH_ENTER(et);
1357 if (ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) {
1358 /* Do not need DAD for ifdisabled interface. */
1359 log(LOG_ERR, "nd6_dad_timer: cancel DAD on %s because of "
1360 "ND6_IFF_IFDISABLED.\n", ifp->if_xname);
1361 goto err;
1362 }
1363 if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
1364 log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
1365 "%s(%s)\n",
1366 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
1367 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1368 goto err;
1369 }
1370 if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
1371 log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
1372 "%s(%s)\n",
1373 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
1374 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1375 goto err;
1376 }
1377
1378 /* Stop DAD if the interface is down even after dad_maxtry attempts. */
1379 if ((dp->dad_ns_tcount > V_dad_maxtry) &&
1380 (((ifp->if_flags & IFF_UP) == 0) ||
1381 ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0))) {
1382 nd6log((LOG_INFO, "%s: could not run DAD "
1383 "because the interface was down or not running.\n",
1384 if_name(ifa->ifa_ifp)));
1385 goto err;
1386 }
1387
1388 /* Need more checks? */
1389 if (dp->dad_ns_ocount < dp->dad_count) {
1390 /*
1391 * We have more NS to go. Send NS packet for DAD.
1392 */
1393 nd6_dad_starttimer(dp,
1394 (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1395 nd6_dad_ns_output(dp);
1396 goto done;
1397 } else {
1398 /*
1399 * We have transmitted sufficient number of DAD packets.
1400 * See what we've got.
1401 */
1402 if (dp->dad_ns_icount > 0 || dp->dad_na_icount > 0) {
1403 /* We've seen NS or NA, means DAD has failed. */
1404 nd6_dad_duplicated(ifa, dp);
1405 } else if (V_dad_enhanced != 0 &&
1406 dp->dad_ns_lcount > 0 &&
1407 dp->dad_ns_lcount > dp->dad_loopbackprobe) {
1408 /*
1409 * Sec. 4.1 in RFC 7527 requires transmission of
1410 * additional probes until the loopback condition
1411 * becomes clear when a looped back probe is detected.
1412 */
1413 log(LOG_ERR, "%s: a looped back NS message is "
1414 "detected during DAD for %s. "
1415 "Another DAD probes are being sent.\n",
1416 if_name(ifa->ifa_ifp),
1417 ip6_sprintf(ip6buf, IFA_IN6(ifa)));
1418 dp->dad_loopbackprobe = dp->dad_ns_lcount;
1419 /*
1420 * Send an NS immediately and increase dad_count by
1421 * V_nd6_mmaxtries - 1.
1422 */
1423 dp->dad_count =
1424 dp->dad_ns_ocount + V_nd6_mmaxtries - 1;
1425 nd6_dad_starttimer(dp,
1426 (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1427 nd6_dad_ns_output(dp);
1428 goto done;
1429 } else {
1430 /*
1431 * We are done with DAD. No NA came, no NS came.
1432 * No duplicate address found. Check IFDISABLED flag
1433 * again in case that it is changed between the
1434 * beginning of this function and here.
1435 */
1436 if ((ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) == 0)
1437 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1438
1439 nd6log((LOG_DEBUG,
1440 "%s: DAD complete for %s - no duplicates found\n",
1441 if_name(ifa->ifa_ifp),
1442 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr)));
1443 if (dp->dad_ns_lcount > 0)
1444 log(LOG_ERR, "%s: DAD completed while "
1445 "a looped back NS message is detected "
1446 "during DAD for %s.\n",
1447 if_name(ifa->ifa_ifp),
1448 ip6_sprintf(ip6buf, IFA_IN6(ifa)));
1449 }
1450 }
1451 err:
1452 nd6_dad_del(dp);
1453 DADQ_WUNLOCK();
1454 done:
1455 NET_EPOCH_EXIT(et);
1456 CURVNET_RESTORE();
1457 }
1458
1459 static void
nd6_dad_duplicated(struct ifaddr * ifa,struct dadq * dp)1460 nd6_dad_duplicated(struct ifaddr *ifa, struct dadq *dp)
1461 {
1462 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1463 struct ifnet *ifp;
1464 char ip6buf[INET6_ADDRSTRLEN];
1465
1466 log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
1467 "NS in/out/loopback=%d/%d/%d, NA in=%d\n",
1468 if_name(ifa->ifa_ifp), ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
1469 dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_ns_lcount,
1470 dp->dad_na_icount);
1471
1472 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1473 ia->ia6_flags |= IN6_IFF_DUPLICATED;
1474
1475 ifp = ifa->ifa_ifp;
1476 log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
1477 if_name(ifp), ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr));
1478 log(LOG_ERR, "%s: manual intervention required\n",
1479 if_name(ifp));
1480
1481 /*
1482 * If the address is a link-local address formed from an interface
1483 * identifier based on the hardware address which is supposed to be
1484 * uniquely assigned (e.g., EUI-64 for an Ethernet interface), IP
1485 * operation on the interface SHOULD be disabled.
1486 * [RFC 4862, Section 5.4.5]
1487 */
1488 if (IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) {
1489 struct in6_addr in6;
1490
1491 /*
1492 * To avoid over-reaction, we only apply this logic when we are
1493 * very sure that hardware addresses are supposed to be unique.
1494 */
1495 switch (ifp->if_type) {
1496 case IFT_ETHER:
1497 case IFT_ATM:
1498 case IFT_IEEE1394:
1499 case IFT_INFINIBAND:
1500 in6 = ia->ia_addr.sin6_addr;
1501 if (in6_get_hw_ifid(ifp, &in6) == 0 &&
1502 IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr, &in6)) {
1503 ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED;
1504 log(LOG_ERR, "%s: possible hardware address "
1505 "duplication detected, disable IPv6\n",
1506 if_name(ifp));
1507 }
1508 break;
1509 }
1510 }
1511 }
1512
1513 /*
1514 * Transmit a neighbour solicitation for the purpose of DAD. Returns with the
1515 * DAD queue unlocked.
1516 */
1517 static void
nd6_dad_ns_output(struct dadq * dp)1518 nd6_dad_ns_output(struct dadq *dp)
1519 {
1520 struct in6_ifaddr *ia = (struct in6_ifaddr *)dp->dad_ifa;
1521 struct ifnet *ifp = dp->dad_ifa->ifa_ifp;
1522 int i;
1523
1524 DADQ_WLOCK_ASSERT();
1525
1526 dp->dad_ns_tcount++;
1527 if ((ifp->if_flags & IFF_UP) == 0) {
1528 DADQ_WUNLOCK();
1529 return;
1530 }
1531 if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
1532 DADQ_WUNLOCK();
1533 return;
1534 }
1535
1536 dp->dad_ns_ocount++;
1537 if (V_dad_enhanced != 0) {
1538 for (i = 0; i < ND_OPT_NONCE_LEN32; i++)
1539 dp->dad_nonce[i] = arc4random();
1540 /*
1541 * XXXHRS: Note that in the case that
1542 * DupAddrDetectTransmits > 1, multiple NS messages with
1543 * different nonces can be looped back in an unexpected
1544 * order. The current implementation recognizes only
1545 * the latest nonce on the sender side. Practically it
1546 * should work well in almost all cases.
1547 */
1548 }
1549 DADQ_WUNLOCK();
1550 nd6_ns_output(ifp, NULL, NULL, &ia->ia_addr.sin6_addr,
1551 (uint8_t *)&dp->dad_nonce[0]);
1552 }
1553
1554 static void
nd6_dad_ns_input(struct ifaddr * ifa,struct nd_opt_nonce * ndopt_nonce)1555 nd6_dad_ns_input(struct ifaddr *ifa, struct nd_opt_nonce *ndopt_nonce)
1556 {
1557 struct dadq *dp;
1558
1559 if (ifa == NULL)
1560 panic("ifa == NULL in nd6_dad_ns_input");
1561
1562 /* Ignore Nonce option when Enhanced DAD is disabled. */
1563 if (V_dad_enhanced == 0)
1564 ndopt_nonce = NULL;
1565 DADQ_RLOCK();
1566 dp = nd6_dad_find(ifa, ndopt_nonce);
1567 if (dp != NULL)
1568 dp->dad_ns_icount++;
1569 DADQ_RUNLOCK();
1570 }
1571
1572 static void
nd6_dad_na_input(struct ifaddr * ifa)1573 nd6_dad_na_input(struct ifaddr *ifa)
1574 {
1575 struct dadq *dp;
1576
1577 if (ifa == NULL)
1578 panic("ifa == NULL in nd6_dad_na_input");
1579
1580 DADQ_RLOCK();
1581 dp = nd6_dad_find(ifa, NULL);
1582 if (dp != NULL)
1583 dp->dad_na_icount++;
1584 DADQ_RUNLOCK();
1585 }
1586