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/if_private.h>
63 #include <net/route.h>
64 #include <net/vnet.h>
65
66 #include <netinet/in.h>
67 #include <netinet/in_var.h>
68 #include <net/if_llatbl.h>
69 #include <netinet6/in6_var.h>
70 #include <netinet6/in6_ifattach.h>
71 #include <netinet/ip6.h>
72 #include <netinet6/ip6_var.h>
73 #include <netinet6/scope6_var.h>
74 #include <netinet6/nd6.h>
75 #include <netinet/icmp6.h>
76 #include <netinet/ip_carp.h>
77 #include <netinet6/send.h>
78
79 #define SDL(s) ((struct sockaddr_dl *)s)
80
81 struct dadq;
82 static struct dadq *nd6_dad_find(struct ifaddr *, struct nd_opt_nonce *);
83 static void nd6_dad_add(struct dadq *dp);
84 static void nd6_dad_del(struct dadq *dp);
85 static void nd6_dad_rele(struct dadq *);
86 static void nd6_dad_starttimer(struct dadq *, int);
87 static void nd6_dad_stoptimer(struct dadq *);
88 static void nd6_dad_timer(void *);
89 static void nd6_dad_duplicated(struct ifaddr *, struct dadq *);
90 static void nd6_dad_ns_output(struct dadq *);
91 static void nd6_dad_ns_input(struct ifaddr *, struct nd_opt_nonce *);
92 static void nd6_dad_na_input(struct ifaddr *);
93 static void nd6_na_output_fib(struct ifnet *, const struct in6_addr *,
94 const struct in6_addr *, u_long, int, struct sockaddr *, u_int);
95 static void nd6_ns_output_fib(struct ifnet *, const struct in6_addr *,
96 const struct in6_addr *, const struct in6_addr *, uint8_t *, u_int);
97
98 static struct ifaddr *nd6_proxy_fill_sdl(struct ifnet *,
99 const struct in6_addr *, struct sockaddr_dl *);
100
101 VNET_DEFINE_STATIC(int, dad_enhanced) = 1;
102 #define V_dad_enhanced VNET(dad_enhanced)
103
104 SYSCTL_DECL(_net_inet6_ip6);
105 SYSCTL_INT(_net_inet6_ip6, OID_AUTO, dad_enhanced, CTLFLAG_VNET | CTLFLAG_RW,
106 &VNET_NAME(dad_enhanced), 0,
107 "Enable Enhanced DAD, which adds a random nonce to NS messages for DAD.");
108
109 VNET_DEFINE_STATIC(int, dad_maxtry) = 15; /* max # of *tries* to
110 transmit DAD packet */
111 #define V_dad_maxtry VNET(dad_maxtry)
112
113 VNET_DEFINE_STATIC(int, nd6_onlink_ns_rfc4861) = 0;
114 #define V_nd6_onlink_ns_rfc4861 VNET(nd6_onlink_ns_rfc4861)
115 SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_ONLINKNSRFC4861,
116 nd6_onlink_ns_rfc4861, CTLFLAG_VNET | CTLFLAG_RW,
117 &VNET_NAME(nd6_onlink_ns_rfc4861), 0,
118 "Accept 'on-link' ICMPv6 NS messages in compliance with RFC 4861");
119
120 /*
121 * Input a Neighbor Solicitation Message.
122 *
123 * Based on RFC 2461
124 * Based on RFC 2462 (duplicate address detection)
125 */
126 void
nd6_ns_input(struct mbuf * m,int off,int icmp6len)127 nd6_ns_input(struct mbuf *m, int off, int icmp6len)
128 {
129 struct ifnet *ifp;
130 struct ip6_hdr *ip6;
131 struct nd_neighbor_solicit *nd_ns;
132 struct in6_addr daddr6, myaddr6, saddr6, taddr6;
133 struct ifaddr *ifa;
134 struct sockaddr_dl proxydl;
135 union nd_opts ndopts;
136 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
137 char *lladdr;
138 int anycast, lladdrlen, proxy, rflag, tentative, tlladdr;
139
140 ifa = NULL;
141
142 /* RFC 6980: Nodes MUST silently ignore fragments */
143 if(m->m_flags & M_FRAGMENTED)
144 goto freeit;
145
146 ifp = m->m_pkthdr.rcvif;
147 ip6 = mtod(m, struct ip6_hdr *);
148 if (__predict_false(ip6->ip6_hlim != 255)) {
149 ICMP6STAT_INC(icp6s_invlhlim);
150 nd6log((LOG_ERR,
151 "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
152 ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
153 ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
154 goto bads;
155 }
156
157 if (m->m_len < off + icmp6len) {
158 m = m_pullup(m, off + icmp6len);
159 if (m == NULL) {
160 IP6STAT_INC(ip6s_exthdrtoolong);
161 return;
162 }
163 }
164 ip6 = mtod(m, struct ip6_hdr *);
165 nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
166
167 saddr6 = ip6->ip6_src;
168 daddr6 = ip6->ip6_dst;
169 taddr6 = nd_ns->nd_ns_target;
170 if (in6_setscope(&taddr6, ifp, NULL) != 0)
171 goto bad;
172
173 rflag = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
174 if (ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV && V_ip6_norbit_raif)
175 rflag = 0;
176
177 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
178 /* dst has to be a solicited node multicast address. */
179 if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
180 /* don't check ifindex portion */
181 daddr6.s6_addr32[1] == 0 &&
182 daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
183 daddr6.s6_addr8[12] == 0xff) {
184 ; /* good */
185 } else {
186 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
187 "(wrong ip6 dst)\n"));
188 goto bad;
189 }
190 } else if (!V_nd6_onlink_ns_rfc4861) {
191 struct sockaddr_in6 src_sa6;
192
193 /*
194 * According to recent IETF discussions, it is not a good idea
195 * to accept a NS from an address which would not be deemed
196 * to be a neighbor otherwise. This point is expected to be
197 * clarified in future revisions of the specification.
198 */
199 bzero(&src_sa6, sizeof(src_sa6));
200 src_sa6.sin6_family = AF_INET6;
201 src_sa6.sin6_len = sizeof(src_sa6);
202 src_sa6.sin6_addr = saddr6;
203 if (nd6_is_addr_neighbor(&src_sa6, ifp) == 0) {
204 nd6log((LOG_INFO, "nd6_ns_input: "
205 "NS packet from non-neighbor\n"));
206 goto bad;
207 }
208 }
209
210 if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
211 nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
212 goto bad;
213 }
214
215 icmp6len -= sizeof(*nd_ns);
216 nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
217 if (nd6_options(&ndopts) < 0) {
218 nd6log((LOG_INFO,
219 "nd6_ns_input: invalid ND option, ignored\n"));
220 /* nd6_options have incremented stats */
221 goto freeit;
222 }
223
224 lladdr = NULL;
225 lladdrlen = 0;
226 if (ndopts.nd_opts_src_lladdr) {
227 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
228 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
229 }
230
231 if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
232 nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
233 "(link-layer address option)\n"));
234 goto bad;
235 }
236
237 /*
238 * Attaching target link-layer address to the NA?
239 * (RFC 2461 7.2.4)
240 *
241 * NS IP dst is unicast/anycast MUST NOT add
242 * NS IP dst is solicited-node multicast MUST add
243 *
244 * In implementation, we add target link-layer address by default.
245 * We do not add one in MUST NOT cases.
246 */
247 if (!IN6_IS_ADDR_MULTICAST(&daddr6))
248 tlladdr = 0;
249 else
250 tlladdr = 1;
251
252 /*
253 * Target address (taddr6) must be either:
254 * (1) Valid unicast/anycast address for my receiving interface,
255 * (2) Unicast address for which I'm offering proxy service, or
256 * (3) "tentative" address on which DAD is being performed.
257 */
258 /* (1) and (3) check. */
259 if (ifp->if_carp)
260 ifa = (*carp_iamatch6_p)(ifp, &taddr6);
261 else
262 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
263
264 /* (2) check. */
265 proxy = 0;
266 if (ifa == NULL) {
267 if ((ifa = nd6_proxy_fill_sdl(ifp, &taddr6, &proxydl)) != NULL)
268 proxy = 1;
269 }
270 if (ifa == NULL) {
271 /*
272 * We've got an NS packet, and we don't have that address
273 * assigned for us. We MUST silently ignore it.
274 * See RFC2461 7.2.3.
275 */
276 goto freeit;
277 }
278 myaddr6 = *IFA_IN6(ifa);
279 anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
280 tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
281 if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
282 goto freeit;
283
284 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
285 nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
286 "(if %d, NS packet %d)\n",
287 ip6_sprintf(ip6bufs, &taddr6),
288 ifp->if_addrlen, lladdrlen - 2));
289 goto bad;
290 }
291
292 if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
293 nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
294 ip6_sprintf(ip6bufs, &saddr6)));
295 goto freeit;
296 }
297
298 /*
299 * We have neighbor solicitation packet, with target address equals to
300 * one of my tentative address.
301 *
302 * src addr how to process?
303 * --- ---
304 * multicast of course, invalid (rejected in ip6_input)
305 * unicast somebody is doing address resolution -> ignore
306 * unspec dup address detection
307 *
308 * The processing is defined in RFC 2462.
309 */
310 if (tentative) {
311 /*
312 * If source address is unspecified address, it is for
313 * duplicate address detection.
314 *
315 * If not, the packet is for addess resolution;
316 * silently ignore it.
317 */
318 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
319 nd6_dad_ns_input(ifa, ndopts.nd_opts_nonce);
320
321 goto freeit;
322 }
323
324 /*
325 * If the source address is unspecified address, entries must not
326 * be created or updated.
327 * It looks that sender is performing DAD. Output NA toward
328 * all-node multicast address, to tell the sender that I'm using
329 * the address.
330 * S bit ("solicited") must be zero.
331 */
332 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
333 struct in6_addr in6_all;
334
335 in6_all = in6addr_linklocal_allnodes;
336 if (in6_setscope(&in6_all, ifp, NULL) != 0)
337 goto bad;
338 nd6_na_output_fib(ifp, &in6_all, &taddr6,
339 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
340 rflag, tlladdr, proxy ? (struct sockaddr *)&proxydl : NULL,
341 M_GETFIB(m));
342 goto freeit;
343 }
344
345 nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen,
346 ND_NEIGHBOR_SOLICIT, 0);
347
348 nd6_na_output_fib(ifp, &saddr6, &taddr6,
349 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
350 rflag | ND_NA_FLAG_SOLICITED, tlladdr,
351 proxy ? (struct sockaddr *)&proxydl : NULL, M_GETFIB(m));
352 freeit:
353 if (ifa != NULL)
354 ifa_free(ifa);
355 m_freem(m);
356 return;
357
358 bad:
359 nd6log((LOG_ERR, "nd6_ns_input: src=%s\n",
360 ip6_sprintf(ip6bufs, &saddr6)));
361 nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n",
362 ip6_sprintf(ip6bufs, &daddr6)));
363 nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n",
364 ip6_sprintf(ip6bufs, &taddr6)));
365 bads:
366 ICMP6STAT_INC(icp6s_badns);
367 if (ifa != NULL)
368 ifa_free(ifa);
369 m_freem(m);
370 }
371
372 static struct ifaddr *
nd6_proxy_fill_sdl(struct ifnet * ifp,const struct in6_addr * taddr6,struct sockaddr_dl * sdl)373 nd6_proxy_fill_sdl(struct ifnet *ifp, const struct in6_addr *taddr6,
374 struct sockaddr_dl *sdl)
375 {
376 struct ifaddr *ifa;
377 struct llentry *ln;
378
379 ifa = NULL;
380 ln = nd6_lookup(taddr6, LLE_SF(AF_INET6, 0), ifp);
381 if (ln == NULL)
382 return (ifa);
383 if ((ln->la_flags & (LLE_PUB | LLE_VALID)) == (LLE_PUB | LLE_VALID)) {
384 link_init_sdl(ifp, (struct sockaddr *)sdl, ifp->if_type);
385 sdl->sdl_alen = ifp->if_addrlen;
386 bcopy(ln->ll_addr, &sdl->sdl_data, ifp->if_addrlen);
387 LLE_RUNLOCK(ln);
388 ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
389 IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
390 } else
391 LLE_RUNLOCK(ln);
392
393 return (ifa);
394 }
395
396 /*
397 * Output a Neighbor Solicitation Message. Caller specifies:
398 * - ICMP6 header source IP6 address
399 * - ND6 header target IP6 address
400 * - ND6 header source datalink address
401 *
402 * Based on RFC 2461
403 * Based on RFC 2462 (duplicate address detection)
404 *
405 * ln - for source address determination
406 * nonce - If non-NULL, NS is used for duplicate address detection and
407 * the value (length is ND_OPT_NONCE_LEN) is used as a random nonce.
408 */
409 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)410 nd6_ns_output_fib(struct ifnet *ifp, const struct in6_addr *saddr6,
411 const struct in6_addr *daddr6, const struct in6_addr *taddr6,
412 uint8_t *nonce, u_int fibnum)
413 {
414 struct mbuf *m;
415 struct m_tag *mtag;
416 struct ip6_hdr *ip6;
417 struct nd_neighbor_solicit *nd_ns;
418 struct ip6_moptions im6o;
419 int icmp6len;
420 int maxlen;
421
422 NET_EPOCH_ASSERT();
423
424 if (IN6_IS_ADDR_MULTICAST(taddr6))
425 return;
426
427 /* estimate the size of message */
428 maxlen = sizeof(*ip6) + sizeof(*nd_ns);
429 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
430 KASSERT(max_linkhdr + maxlen <= MCLBYTES, (
431 "%s: max_linkhdr + maxlen > MCLBYTES (%d + %d > %d)",
432 __func__, max_linkhdr, maxlen, MCLBYTES));
433
434 if (max_linkhdr + maxlen > MHLEN)
435 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
436 else
437 m = m_gethdr(M_NOWAIT, MT_DATA);
438 if (m == NULL)
439 return;
440 M_SETFIB(m, fibnum);
441
442 if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
443 m->m_flags |= M_MCAST;
444 im6o.im6o_multicast_ifp = ifp;
445 im6o.im6o_multicast_hlim = 255;
446 im6o.im6o_multicast_loop = 0;
447 }
448
449 icmp6len = sizeof(*nd_ns);
450 m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
451 m->m_data += max_linkhdr; /* or M_ALIGN() equivalent? */
452
453 /* fill neighbor solicitation packet */
454 ip6 = mtod(m, struct ip6_hdr *);
455 ip6->ip6_flow = 0;
456 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
457 ip6->ip6_vfc |= IPV6_VERSION;
458 /* ip6->ip6_plen will be set later */
459 ip6->ip6_nxt = IPPROTO_ICMPV6;
460 ip6->ip6_hlim = 255;
461 if (daddr6)
462 ip6->ip6_dst = *daddr6;
463 else {
464 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
465 ip6->ip6_dst.s6_addr16[1] = 0;
466 ip6->ip6_dst.s6_addr32[1] = 0;
467 ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
468 ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
469 ip6->ip6_dst.s6_addr8[12] = 0xff;
470 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
471 goto bad;
472 }
473 if (nonce == NULL) {
474 char ip6buf[INET6_ADDRSTRLEN];
475 struct ifaddr *ifa = NULL;
476
477 /*
478 * RFC2461 7.2.2:
479 * "If the source address of the packet prompting the
480 * solicitation is the same as one of the addresses assigned
481 * to the outgoing interface, that address SHOULD be placed
482 * in the IP Source Address of the outgoing solicitation.
483 * Otherwise, any one of the addresses assigned to the
484 * interface should be used."
485 *
486 * We use the source address for the prompting packet
487 * (saddr6), if saddr6 belongs to the outgoing interface.
488 * Otherwise, we perform the source address selection as usual.
489 */
490 if (saddr6 != NULL)
491 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, saddr6);
492 if (ifa == NULL) {
493 int error;
494 struct in6_addr dst6, src6;
495 uint32_t scopeid;
496
497 in6_splitscope(&ip6->ip6_dst, &dst6, &scopeid);
498 error = in6_selectsrc_addr(fibnum, &dst6,
499 scopeid, ifp, &src6, NULL);
500 if (error) {
501 nd6log((LOG_DEBUG, "%s: source can't be "
502 "determined: dst=%s, error=%d\n", __func__,
503 ip6_sprintf(ip6buf, &dst6),
504 error));
505 goto bad;
506 }
507 ip6->ip6_src = src6;
508 } else
509 ip6->ip6_src = *saddr6;
510
511 if (ifp->if_carp != NULL) {
512 /*
513 * Check that selected source address belongs to
514 * CARP addresses.
515 */
516 if (ifa == NULL)
517 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp,
518 &ip6->ip6_src);
519 /*
520 * Do not send NS for CARP address if we are not
521 * the CARP master.
522 */
523 if (ifa != NULL && ifa->ifa_carp != NULL &&
524 !(*carp_master_p)(ifa)) {
525 nd6log((LOG_DEBUG,
526 "nd6_ns_output: NS from BACKUP CARP address %s\n",
527 ip6_sprintf(ip6buf, &ip6->ip6_src)));
528 ifa_free(ifa);
529 goto bad;
530 }
531 }
532 if (ifa != NULL)
533 ifa_free(ifa);
534 } else {
535 /*
536 * Source address for DAD packet must always be IPv6
537 * unspecified address. (0::0)
538 * We actually don't have to 0-clear the address (we did it
539 * above), but we do so here explicitly to make the intention
540 * clearer.
541 */
542 bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
543 }
544 nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
545 nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
546 nd_ns->nd_ns_code = 0;
547 nd_ns->nd_ns_reserved = 0;
548 nd_ns->nd_ns_target = *taddr6;
549 in6_clearscope(&nd_ns->nd_ns_target); /* XXX */
550
551 /*
552 * Add source link-layer address option.
553 *
554 * spec implementation
555 * --- ---
556 * DAD packet MUST NOT do not add the option
557 * there's no link layer address:
558 * impossible do not add the option
559 * there's link layer address:
560 * Multicast NS MUST add one add the option
561 * Unicast NS SHOULD add one add the option
562 */
563 if (nonce == NULL) {
564 struct nd_opt_hdr *nd_opt;
565 char *mac;
566 int optlen;
567
568 mac = NULL;
569 if (ifp->if_carp)
570 mac = (*carp_macmatch6_p)(ifp, m, &ip6->ip6_src);
571 if (mac == NULL)
572 mac = nd6_ifptomac(ifp);
573
574 if (mac != NULL) {
575 nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
576 optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
577 /* 8 byte alignments... */
578 optlen = (optlen + 7) & ~7;
579 m->m_pkthdr.len += optlen;
580 m->m_len += optlen;
581 icmp6len += optlen;
582 bzero(nd_opt, optlen);
583 nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
584 nd_opt->nd_opt_len = optlen >> 3;
585 bcopy(mac, nd_opt + 1, ifp->if_addrlen);
586 }
587 }
588 /*
589 * Add a Nonce option (RFC 3971) to detect looped back NS messages.
590 * This behavior is documented as Enhanced Duplicate Address
591 * Detection in RFC 7527.
592 * net.inet6.ip6.dad_enhanced=0 disables this.
593 */
594 if (V_dad_enhanced != 0 && nonce != NULL) {
595 int optlen = sizeof(struct nd_opt_hdr) + ND_OPT_NONCE_LEN;
596 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
597 /* 8-byte alignment is required. */
598 optlen = (optlen + 7) & ~7;
599
600 m->m_pkthdr.len += optlen;
601 m->m_len += optlen;
602 icmp6len += optlen;
603 bzero((caddr_t)nd_opt, optlen);
604 nd_opt->nd_opt_type = ND_OPT_NONCE;
605 nd_opt->nd_opt_len = optlen >> 3;
606 bcopy(nonce, (caddr_t)(nd_opt + 1), ND_OPT_NONCE_LEN);
607 }
608 ip6->ip6_plen = htons((u_short)icmp6len);
609 nd_ns->nd_ns_cksum = 0;
610 nd_ns->nd_ns_cksum =
611 in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
612
613 if (send_sendso_input_hook != NULL) {
614 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
615 sizeof(unsigned short), M_NOWAIT);
616 if (mtag == NULL)
617 goto bad;
618 *(unsigned short *)(mtag + 1) = nd_ns->nd_ns_type;
619 m_tag_prepend(m, mtag);
620 }
621
622 ip6_output(m, NULL, NULL, (nonce != NULL) ? IPV6_UNSPECSRC : 0,
623 &im6o, NULL, NULL);
624 icmp6_ifstat_inc(ifp, ifs6_out_msg);
625 icmp6_ifstat_inc(ifp, ifs6_out_neighborsolicit);
626 ICMP6STAT_INC2(icp6s_outhist, ND_NEIGHBOR_SOLICIT);
627
628 return;
629
630 bad:
631 m_freem(m);
632 }
633
634 #ifndef BURN_BRIDGES
635 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)636 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *saddr6,
637 const struct in6_addr *daddr6, const struct in6_addr *taddr6,uint8_t *nonce)
638 {
639
640 nd6_ns_output_fib(ifp, saddr6, daddr6, taddr6, nonce, RT_DEFAULT_FIB);
641 }
642 #endif
643 /*
644 * Neighbor advertisement input handling.
645 *
646 * Based on RFC 2461
647 * Based on RFC 2462 (duplicate address detection)
648 *
649 * the following items are not implemented yet:
650 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
651 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
652 */
653 void
nd6_na_input(struct mbuf * m,int off,int icmp6len)654 nd6_na_input(struct mbuf *m, int off, int icmp6len)
655 {
656 struct ifnet *ifp;
657 struct ip6_hdr *ip6;
658 struct ifaddr *ifa;
659 struct llentry *ln;
660 struct mbuf *chain;
661 struct nd_neighbor_advert *nd_na;
662 struct in6_addr daddr6, taddr6;
663 union nd_opts ndopts;
664 u_char linkhdr[LLE_MAX_LINKHDR];
665 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
666 char *lladdr;
667 size_t linkhdrsize;
668 int flags, is_override, is_router, is_solicited;
669 int lladdr_off, lladdrlen, checklink;
670 bool flush_holdchain = false;
671
672 NET_EPOCH_ASSERT();
673
674 chain = NULL;
675 ln = NULL;
676 checklink = 0;
677
678 /* RFC 6980: Nodes MUST silently ignore fragments */
679 if(m->m_flags & M_FRAGMENTED)
680 goto freeit;
681
682 ifp = m->m_pkthdr.rcvif;
683 ip6 = mtod(m, struct ip6_hdr *);
684 if (__predict_false(ip6->ip6_hlim != 255)) {
685 ICMP6STAT_INC(icp6s_invlhlim);
686 nd6log((LOG_ERR,
687 "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
688 ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
689 ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
690 goto bad;
691 }
692
693 if (m->m_len < off + icmp6len) {
694 m = m_pullup(m, off + icmp6len);
695 if (m == NULL) {
696 IP6STAT_INC(ip6s_exthdrtoolong);
697 return;
698 }
699 }
700 ip6 = mtod(m, struct ip6_hdr *);
701 nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
702
703 flags = nd_na->nd_na_flags_reserved;
704 is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
705 is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
706 is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
707
708 taddr6 = nd_na->nd_na_target;
709 if (in6_setscope(&taddr6, ifp, NULL))
710 goto bad; /* XXX: impossible */
711
712 if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
713 nd6log((LOG_ERR,
714 "nd6_na_input: invalid target address %s\n",
715 ip6_sprintf(ip6bufs, &taddr6)));
716 goto bad;
717 }
718
719 daddr6 = ip6->ip6_dst;
720 if (IN6_IS_ADDR_MULTICAST(&daddr6))
721 if (is_solicited) {
722 nd6log((LOG_ERR,
723 "nd6_na_input: a solicited adv is multicasted\n"));
724 goto bad;
725 }
726
727 icmp6len -= sizeof(*nd_na);
728 nd6_option_init(nd_na + 1, icmp6len, &ndopts);
729 if (nd6_options(&ndopts) < 0) {
730 nd6log((LOG_INFO,
731 "nd6_na_input: invalid ND option, ignored\n"));
732 /* nd6_options have incremented stats */
733 goto freeit;
734 }
735
736 lladdr = NULL;
737 lladdrlen = 0;
738 if (ndopts.nd_opts_tgt_lladdr) {
739 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
740 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
741 }
742
743 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
744 if (ifa != NULL && ifa->ifa_carp != NULL) {
745 /*
746 * Silently ignore NAs for CARP addresses if we are not
747 * the CARP master.
748 */
749 if (!(*carp_master_p)(ifa)) {
750 nd6log((LOG_DEBUG,
751 "nd6_na_input: NA for BACKUP CARP address %s\n",
752 ip6_sprintf(ip6bufs, &taddr6)));
753 ifa_free(ifa);
754 goto freeit;
755 }
756 }
757 /*
758 * Target address matches one of my interface address.
759 *
760 * If my address is tentative, this means that there's somebody
761 * already using the same address as mine. This indicates DAD failure.
762 * This is defined in RFC 2462.
763 *
764 * Otherwise, process as defined in RFC 2461.
765 */
766 if (ifa
767 && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
768 nd6_dad_na_input(ifa);
769 ifa_free(ifa);
770 goto freeit;
771 }
772
773 /* Just for safety, maybe unnecessary. */
774 if (ifa) {
775 ifa_free(ifa);
776 log(LOG_ERR,
777 "nd6_na_input: duplicate IP6 address %s\n",
778 ip6_sprintf(ip6bufs, &taddr6));
779 goto freeit;
780 }
781
782 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
783 nd6log((LOG_INFO, "nd6_na_input: lladdrlen mismatch for %s "
784 "(if %d, NA packet %d)\n", ip6_sprintf(ip6bufs, &taddr6),
785 ifp->if_addrlen, lladdrlen - 2));
786 goto bad;
787 }
788
789 /*
790 * If no neighbor cache entry is found, NA SHOULD silently be
791 * discarded.
792 */
793 ln = nd6_lookup(&taddr6, LLE_SF(AF_INET6, LLE_EXCLUSIVE), ifp);
794 if (ln == NULL) {
795 goto freeit;
796 }
797
798 /*
799 * Do not try to override static entry.
800 */
801 if (ln->la_flags & LLE_STATIC)
802 goto freeit;
803
804 if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
805 /*
806 * If the link-layer has address, and no lladdr option came,
807 * discard the packet.
808 */
809 if (ifp->if_addrlen && lladdr == NULL) {
810 goto freeit;
811 }
812
813 /*
814 * Record link-layer address, and update the state.
815 */
816 if (!nd6_try_set_entry_addr(ifp, ln, lladdr))
817 goto freeit;
818
819 flush_holdchain = true;
820 if (is_solicited)
821 nd6_llinfo_setstate(ln, ND6_LLINFO_REACHABLE);
822 else
823 nd6_llinfo_setstate(ln, ND6_LLINFO_STALE);
824 EVENTHANDLER_INVOKE(lle_event, ln, LLENTRY_RESOLVED);
825 if ((ln->ln_router = is_router) != 0) {
826 /*
827 * This means a router's state has changed from
828 * non-reachable to probably reachable, and might
829 * affect the status of associated prefixes..
830 */
831 checklink = 1;
832 }
833 } else {
834 int llchange;
835
836 /*
837 * Check if the link-layer address has changed or not.
838 */
839 if (lladdr == NULL)
840 llchange = 0;
841 else {
842 if (ln->la_flags & LLE_VALID) {
843 if (bcmp(lladdr, ln->ll_addr, ifp->if_addrlen))
844 llchange = 1;
845 else
846 llchange = 0;
847 } else
848 llchange = 1;
849 }
850
851 /*
852 * This is VERY complex. Look at it with care.
853 *
854 * override solicit lladdr llchange action
855 * (L: record lladdr)
856 *
857 * 0 0 n -- (2c)
858 * 0 0 y n (2b) L
859 * 0 0 y y (1) REACHABLE->STALE
860 * 0 1 n -- (2c) *->REACHABLE
861 * 0 1 y n (2b) L *->REACHABLE
862 * 0 1 y y (1) REACHABLE->STALE
863 * 1 0 n -- (2a)
864 * 1 0 y n (2a) L
865 * 1 0 y y (2a) L *->STALE
866 * 1 1 n -- (2a) *->REACHABLE
867 * 1 1 y n (2a) L *->REACHABLE
868 * 1 1 y y (2a) L *->REACHABLE
869 */
870 if (!is_override && (lladdr != NULL && llchange)) { /* (1) */
871 /*
872 * If state is REACHABLE, make it STALE.
873 * no other updates should be done.
874 */
875 if (ln->ln_state == ND6_LLINFO_REACHABLE)
876 nd6_llinfo_setstate(ln, ND6_LLINFO_STALE);
877 goto freeit;
878 } else if (is_override /* (2a) */
879 || (!is_override && (lladdr != NULL && !llchange)) /* (2b) */
880 || lladdr == NULL) { /* (2c) */
881 /*
882 * Update link-local address, if any.
883 */
884 if (lladdr != NULL) {
885 linkhdrsize = sizeof(linkhdr);
886 if (lltable_calc_llheader(ifp, AF_INET6, lladdr,
887 linkhdr, &linkhdrsize, &lladdr_off) != 0)
888 goto freeit;
889 if (lltable_try_set_entry_addr(ifp, ln, linkhdr,
890 linkhdrsize, lladdr_off) == 0)
891 goto freeit;
892 EVENTHANDLER_INVOKE(lle_event, ln,
893 LLENTRY_RESOLVED);
894 }
895
896 /*
897 * If solicited, make the state REACHABLE.
898 * If not solicited and the link-layer address was
899 * changed, make it STALE.
900 */
901 if (is_solicited)
902 nd6_llinfo_setstate(ln, ND6_LLINFO_REACHABLE);
903 else {
904 if (lladdr != NULL && llchange)
905 nd6_llinfo_setstate(ln, ND6_LLINFO_STALE);
906 }
907 }
908
909 if (ln->ln_router && !is_router) {
910 /*
911 * The peer dropped the router flag.
912 * Remove the sender from the Default Router List and
913 * update the Destination Cache entries.
914 */
915 struct ifnet *nd6_ifp;
916
917 nd6_ifp = lltable_get_ifp(ln->lle_tbl);
918 if (!defrouter_remove(&ln->r_l3addr.addr6, nd6_ifp) &&
919 (ND_IFINFO(nd6_ifp)->flags &
920 ND6_IFF_ACCEPT_RTADV) != 0)
921 /*
922 * Even if the neighbor is not in the default
923 * router list, the neighbor may be used as a
924 * next hop for some destinations (e.g. redirect
925 * case). So we must call rt6_flush explicitly.
926 */
927 rt6_flush(&ip6->ip6_src, ifp);
928 }
929 ln->ln_router = is_router;
930 }
931 /* XXX - QL
932 * Does this matter?
933 * rt->rt_flags &= ~RTF_REJECT;
934 */
935 ln->la_asked = 0;
936 if (ln->la_hold != NULL)
937 chain = nd6_grab_holdchain(ln);
938 freeit:
939 if (ln != NULL)
940 LLE_WUNLOCK(ln);
941
942 if (chain != NULL)
943 nd6_flush_holdchain(ifp, ln, chain);
944 if (flush_holdchain)
945 nd6_flush_children_holdchain(ifp, ln);
946
947 if (checklink)
948 pfxlist_onlink_check();
949
950 m_freem(m);
951 return;
952
953 bad:
954 if (ln != NULL)
955 LLE_WUNLOCK(ln);
956
957 ICMP6STAT_INC(icp6s_badna);
958 m_freem(m);
959 }
960
961 /*
962 * Neighbor advertisement output handling.
963 *
964 * Based on RFC 2461
965 *
966 * the following items are not implemented yet:
967 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
968 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
969 *
970 * tlladdr - 1 if include target link-layer address
971 * sdl0 - sockaddr_dl (= proxy NA) or NULL
972 */
973 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)974 nd6_na_output_fib(struct ifnet *ifp, const struct in6_addr *daddr6_0,
975 const struct in6_addr *taddr6, u_long flags, int tlladdr,
976 struct sockaddr *sdl0, u_int fibnum)
977 {
978 struct mbuf *m;
979 struct m_tag *mtag;
980 struct ip6_hdr *ip6;
981 struct nd_neighbor_advert *nd_na;
982 struct ip6_moptions im6o;
983 struct in6_addr daddr6, dst6, src6;
984 uint32_t scopeid;
985
986 NET_EPOCH_ASSERT();
987
988 int icmp6len, maxlen, error;
989 caddr_t mac = NULL;
990
991 daddr6 = *daddr6_0; /* make a local copy for modification */
992
993 /* estimate the size of message */
994 maxlen = sizeof(*ip6) + sizeof(*nd_na);
995 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
996 KASSERT(max_linkhdr + maxlen <= MCLBYTES, (
997 "%s: max_linkhdr + maxlen > MCLBYTES (%d + %d > %d)",
998 __func__, max_linkhdr, maxlen, MCLBYTES));
999
1000 if (max_linkhdr + maxlen > MHLEN)
1001 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
1002 else
1003 m = m_gethdr(M_NOWAIT, MT_DATA);
1004 if (m == NULL)
1005 return;
1006 M_SETFIB(m, fibnum);
1007
1008 if (IN6_IS_ADDR_MULTICAST(&daddr6)) {
1009 m->m_flags |= M_MCAST;
1010 im6o.im6o_multicast_ifp = ifp;
1011 im6o.im6o_multicast_hlim = 255;
1012 im6o.im6o_multicast_loop = 0;
1013 }
1014
1015 icmp6len = sizeof(*nd_na);
1016 m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
1017 m->m_data += max_linkhdr; /* or M_ALIGN() equivalent? */
1018
1019 /* fill neighbor advertisement packet */
1020 ip6 = mtod(m, struct ip6_hdr *);
1021 ip6->ip6_flow = 0;
1022 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
1023 ip6->ip6_vfc |= IPV6_VERSION;
1024 ip6->ip6_nxt = IPPROTO_ICMPV6;
1025 ip6->ip6_hlim = 255;
1026 if (IN6_IS_ADDR_UNSPECIFIED(&daddr6)) {
1027 /* reply to DAD */
1028 daddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
1029 daddr6.s6_addr16[1] = 0;
1030 daddr6.s6_addr32[1] = 0;
1031 daddr6.s6_addr32[2] = 0;
1032 daddr6.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
1033 if (in6_setscope(&daddr6, ifp, NULL))
1034 goto bad;
1035
1036 flags &= ~ND_NA_FLAG_SOLICITED;
1037 }
1038 ip6->ip6_dst = daddr6;
1039
1040 /*
1041 * Select a source whose scope is the same as that of the dest.
1042 */
1043 in6_splitscope(&daddr6, &dst6, &scopeid);
1044 error = in6_selectsrc_addr(fibnum, &dst6,
1045 scopeid, ifp, &src6, NULL);
1046 if (error) {
1047 char ip6buf[INET6_ADDRSTRLEN];
1048 nd6log((LOG_DEBUG, "nd6_na_output: source can't be "
1049 "determined: dst=%s, error=%d\n",
1050 ip6_sprintf(ip6buf, &daddr6), error));
1051 goto bad;
1052 }
1053 ip6->ip6_src = src6;
1054 nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
1055 nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
1056 nd_na->nd_na_code = 0;
1057 nd_na->nd_na_target = *taddr6;
1058 in6_clearscope(&nd_na->nd_na_target); /* XXX */
1059
1060 /*
1061 * "tlladdr" indicates NS's condition for adding tlladdr or not.
1062 * see nd6_ns_input() for details.
1063 * Basically, if NS packet is sent to unicast/anycast addr,
1064 * target lladdr option SHOULD NOT be included.
1065 */
1066 if (tlladdr) {
1067 /*
1068 * sdl0 != NULL indicates proxy NA. If we do proxy, use
1069 * lladdr in sdl0. If we are not proxying (sending NA for
1070 * my address) use lladdr configured for the interface.
1071 */
1072 if (sdl0 == NULL) {
1073 if (ifp->if_carp)
1074 mac = (*carp_macmatch6_p)(ifp, m, taddr6);
1075 if (mac == NULL)
1076 mac = nd6_ifptomac(ifp);
1077 } else if (sdl0->sa_family == AF_LINK) {
1078 struct sockaddr_dl *sdl;
1079 sdl = (struct sockaddr_dl *)sdl0;
1080 if (sdl->sdl_alen == ifp->if_addrlen)
1081 mac = LLADDR(sdl);
1082 }
1083 }
1084 if (tlladdr && mac) {
1085 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
1086 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
1087
1088 /* roundup to 8 bytes alignment! */
1089 optlen = (optlen + 7) & ~7;
1090
1091 m->m_pkthdr.len += optlen;
1092 m->m_len += optlen;
1093 icmp6len += optlen;
1094 bzero((caddr_t)nd_opt, optlen);
1095 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
1096 nd_opt->nd_opt_len = optlen >> 3;
1097 bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
1098 } else
1099 flags &= ~ND_NA_FLAG_OVERRIDE;
1100
1101 ip6->ip6_plen = htons((u_short)icmp6len);
1102 nd_na->nd_na_flags_reserved = flags;
1103 nd_na->nd_na_cksum = 0;
1104 nd_na->nd_na_cksum =
1105 in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
1106
1107 if (send_sendso_input_hook != NULL) {
1108 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING,
1109 sizeof(unsigned short), M_NOWAIT);
1110 if (mtag == NULL)
1111 goto bad;
1112 *(unsigned short *)(mtag + 1) = nd_na->nd_na_type;
1113 m_tag_prepend(m, mtag);
1114 }
1115
1116 ip6_output(m, NULL, NULL, 0, &im6o, NULL, NULL);
1117 icmp6_ifstat_inc(ifp, ifs6_out_msg);
1118 icmp6_ifstat_inc(ifp, ifs6_out_neighboradvert);
1119 ICMP6STAT_INC2(icp6s_outhist, ND_NEIGHBOR_ADVERT);
1120
1121 return;
1122
1123 bad:
1124 m_freem(m);
1125 }
1126
1127 #ifndef BURN_BRIDGES
1128 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)1129 nd6_na_output(struct ifnet *ifp, const struct in6_addr *daddr6_0,
1130 const struct in6_addr *taddr6, u_long flags, int tlladdr,
1131 struct sockaddr *sdl0)
1132 {
1133
1134 nd6_na_output_fib(ifp, daddr6_0, taddr6, flags, tlladdr, sdl0,
1135 RT_DEFAULT_FIB);
1136 }
1137 #endif
1138
1139 caddr_t
nd6_ifptomac(struct ifnet * ifp)1140 nd6_ifptomac(struct ifnet *ifp)
1141 {
1142 switch (ifp->if_type) {
1143 case IFT_ETHER:
1144 case IFT_IEEE1394:
1145 case IFT_L2VLAN:
1146 case IFT_INFINIBAND:
1147 case IFT_BRIDGE:
1148 return IF_LLADDR(ifp);
1149 default:
1150 return NULL;
1151 }
1152 }
1153
1154 struct dadq {
1155 TAILQ_ENTRY(dadq) dad_list;
1156 struct ifaddr *dad_ifa;
1157 int dad_count; /* max NS to send */
1158 int dad_ns_tcount; /* # of trials to send NS */
1159 int dad_ns_ocount; /* NS sent so far */
1160 int dad_ns_icount;
1161 int dad_na_icount;
1162 int dad_ns_lcount; /* looped back NS */
1163 int dad_loopbackprobe; /* probing state for loopback detection */
1164 struct callout dad_timer_ch;
1165 struct vnet *dad_vnet;
1166 u_int dad_refcnt;
1167 #define ND_OPT_NONCE_LEN32 \
1168 ((ND_OPT_NONCE_LEN + sizeof(uint32_t) - 1)/sizeof(uint32_t))
1169 uint32_t dad_nonce[ND_OPT_NONCE_LEN32];
1170 bool dad_ondadq; /* on dadq? Protected by DADQ_WLOCK. */
1171 };
1172
1173 VNET_DEFINE_STATIC(TAILQ_HEAD(, dadq), dadq);
1174 VNET_DEFINE_STATIC(struct rwlock, dad_rwlock);
1175 #define V_dadq VNET(dadq)
1176 #define V_dad_rwlock VNET(dad_rwlock)
1177
1178 #define DADQ_LOCKPTR() (&V_dad_rwlock)
1179 #define DADQ_LOCK_INIT() rw_init(DADQ_LOCKPTR(), "nd6 DAD queue")
1180 #define DADQ_RLOCK() rw_rlock(DADQ_LOCKPTR())
1181 #define DADQ_RUNLOCK() rw_runlock(DADQ_LOCKPTR())
1182 #define DADQ_WLOCK() rw_wlock(DADQ_LOCKPTR())
1183 #define DADQ_WUNLOCK() rw_wunlock(DADQ_LOCKPTR())
1184
1185 #define DADQ_LOCK_ASSERT() rw_assert(DADQ_LOCKPTR(), RA_LOCKED);
1186 #define DADQ_RLOCK_ASSERT() rw_assert(DADQ_LOCKPTR(), RA_RLOCKED);
1187 #define DADQ_WLOCK_ASSERT() rw_assert(DADQ_LOCKPTR(), RA_WLOCKED);
1188
1189 static void
nd6_dad_add(struct dadq * dp)1190 nd6_dad_add(struct dadq *dp)
1191 {
1192 DADQ_WLOCK_ASSERT();
1193
1194 TAILQ_INSERT_TAIL(&V_dadq, dp, dad_list);
1195 dp->dad_ondadq = true;
1196 }
1197
1198 static void
nd6_dad_del(struct dadq * dp)1199 nd6_dad_del(struct dadq *dp)
1200 {
1201 DADQ_WLOCK_ASSERT();
1202
1203 if (dp->dad_ondadq) {
1204 /*
1205 * Remove dp from the dadq and release the dadq's
1206 * reference.
1207 */
1208 TAILQ_REMOVE(&V_dadq, dp, dad_list);
1209 dp->dad_ondadq = false;
1210 nd6_dad_rele(dp);
1211 }
1212 }
1213
1214 static struct dadq *
nd6_dad_find(struct ifaddr * ifa,struct nd_opt_nonce * n)1215 nd6_dad_find(struct ifaddr *ifa, struct nd_opt_nonce *n)
1216 {
1217 struct dadq *dp;
1218
1219 DADQ_LOCK_ASSERT();
1220
1221 TAILQ_FOREACH(dp, &V_dadq, dad_list) {
1222 if (dp->dad_ifa != ifa)
1223 continue;
1224
1225 /*
1226 * Skip if the nonce matches the received one.
1227 * +2 in the length is required because of type and
1228 * length fields are included in a header.
1229 */
1230 if (n != NULL &&
1231 n->nd_opt_nonce_len == (ND_OPT_NONCE_LEN + 2) / 8 &&
1232 memcmp(&n->nd_opt_nonce[0], &dp->dad_nonce[0],
1233 ND_OPT_NONCE_LEN) == 0) {
1234 dp->dad_ns_lcount++;
1235 continue;
1236 }
1237 break;
1238 }
1239
1240 return (dp);
1241 }
1242
1243 static void
nd6_dad_starttimer(struct dadq * dp,int ticks)1244 nd6_dad_starttimer(struct dadq *dp, int ticks)
1245 {
1246 DADQ_WLOCK_ASSERT();
1247
1248 callout_reset(&dp->dad_timer_ch, ticks, nd6_dad_timer, dp);
1249 }
1250
1251 static void
nd6_dad_stoptimer(struct dadq * dp)1252 nd6_dad_stoptimer(struct dadq *dp)
1253 {
1254 callout_drain(&dp->dad_timer_ch);
1255 }
1256
1257 static void
nd6_dad_rele(struct dadq * dp)1258 nd6_dad_rele(struct dadq *dp)
1259 {
1260 if (refcount_release(&dp->dad_refcnt)) {
1261 KASSERT(!dp->dad_ondadq, ("dp %p still on DAD queue", dp));
1262 ifa_free(dp->dad_ifa);
1263 free(dp, M_IP6NDP);
1264 }
1265 }
1266
1267 void
nd6_dad_init(void)1268 nd6_dad_init(void)
1269 {
1270 DADQ_LOCK_INIT();
1271 TAILQ_INIT(&V_dadq);
1272 }
1273
1274 /*
1275 * Start Duplicate Address Detection (DAD) for specified interface address.
1276 */
1277 void
nd6_dad_start(struct ifaddr * ifa,int delay)1278 nd6_dad_start(struct ifaddr *ifa, int delay)
1279 {
1280 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1281 struct dadq *dp;
1282 char ip6buf[INET6_ADDRSTRLEN];
1283
1284 KASSERT((ia->ia6_flags & IN6_IFF_TENTATIVE) != 0,
1285 ("starting DAD on non-tentative address %p", ifa));
1286
1287 /*
1288 * If we don't need DAD, don't do it.
1289 * There are several cases:
1290 * - DAD is disabled globally or on the interface
1291 * - the interface address is anycast
1292 */
1293 if ((ia->ia6_flags & IN6_IFF_ANYCAST) != 0 ||
1294 V_ip6_dad_count == 0 ||
1295 (ND_IFINFO(ifa->ifa_ifp)->flags & ND6_IFF_NO_DAD) != 0) {
1296 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1297 return;
1298 }
1299 if ((ifa->ifa_ifp->if_flags & IFF_UP) == 0 ||
1300 (ifa->ifa_ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
1301 (ND_IFINFO(ifa->ifa_ifp)->flags & ND6_IFF_IFDISABLED) != 0)
1302 return;
1303
1304 DADQ_WLOCK();
1305 if ((dp = nd6_dad_find(ifa, NULL)) != NULL) {
1306 /*
1307 * DAD is already in progress. Let the existing entry
1308 * finish it.
1309 */
1310 DADQ_WUNLOCK();
1311 return;
1312 }
1313
1314 dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT | M_ZERO);
1315 if (dp == NULL) {
1316 log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
1317 "%s(%s)\n",
1318 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
1319 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1320 return;
1321 }
1322 callout_init_rw(&dp->dad_timer_ch, DADQ_LOCKPTR(),
1323 CALLOUT_RETURNUNLOCKED);
1324 #ifdef VIMAGE
1325 dp->dad_vnet = curvnet;
1326 #endif
1327 nd6log((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
1328 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr)));
1329
1330 /*
1331 * Send NS packet for DAD, ip6_dad_count times.
1332 * Note that we must delay the first transmission, if this is the
1333 * first packet to be sent from the interface after interface
1334 * (re)initialization.
1335 */
1336 dp->dad_ifa = ifa;
1337 ifa_ref(dp->dad_ifa);
1338 dp->dad_count = V_ip6_dad_count;
1339 dp->dad_ns_icount = dp->dad_na_icount = 0;
1340 dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
1341 dp->dad_ns_lcount = dp->dad_loopbackprobe = 0;
1342
1343 /* Add this to the dadq and add a reference for the dadq. */
1344 refcount_init(&dp->dad_refcnt, 1);
1345 nd6_dad_add(dp);
1346 nd6_dad_starttimer(dp, delay);
1347 DADQ_WUNLOCK();
1348 }
1349
1350 /*
1351 * terminate DAD unconditionally. used for address removals.
1352 */
1353 void
nd6_dad_stop(struct ifaddr * ifa)1354 nd6_dad_stop(struct ifaddr *ifa)
1355 {
1356 struct dadq *dp;
1357
1358 DADQ_WLOCK();
1359 dp = nd6_dad_find(ifa, NULL);
1360 if (dp == NULL) {
1361 DADQ_WUNLOCK();
1362 /* DAD wasn't started yet */
1363 return;
1364 }
1365
1366 /*
1367 * Acquire a temporary reference so that we can safely stop the callout.
1368 */
1369 (void)refcount_acquire(&dp->dad_refcnt);
1370 nd6_dad_del(dp);
1371 DADQ_WUNLOCK();
1372
1373 nd6_dad_stoptimer(dp);
1374 nd6_dad_rele(dp);
1375 }
1376
1377 static void
nd6_dad_timer(void * arg)1378 nd6_dad_timer(void *arg)
1379 {
1380 struct dadq *dp = arg;
1381 struct ifaddr *ifa = dp->dad_ifa;
1382 struct ifnet *ifp = dp->dad_ifa->ifa_ifp;
1383 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1384 char ip6buf[INET6_ADDRSTRLEN];
1385 struct epoch_tracker et;
1386
1387 CURVNET_SET(dp->dad_vnet);
1388 KASSERT(ia != NULL, ("DAD entry %p with no address", dp));
1389
1390 NET_EPOCH_ENTER(et);
1391 if (ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) {
1392 /* Do not need DAD for ifdisabled interface. */
1393 log(LOG_ERR, "nd6_dad_timer: cancel DAD on %s because of "
1394 "ND6_IFF_IFDISABLED.\n", ifp->if_xname);
1395 goto err;
1396 }
1397 if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
1398 log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
1399 "%s(%s)\n",
1400 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
1401 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1402 goto err;
1403 }
1404 if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
1405 log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
1406 "%s(%s)\n",
1407 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
1408 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1409 goto err;
1410 }
1411
1412 /* Stop DAD if the interface is down even after dad_maxtry attempts. */
1413 if ((dp->dad_ns_tcount > V_dad_maxtry) &&
1414 (((ifp->if_flags & IFF_UP) == 0) ||
1415 ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0))) {
1416 nd6log((LOG_INFO, "%s: could not run DAD "
1417 "because the interface was down or not running.\n",
1418 if_name(ifa->ifa_ifp)));
1419 goto err;
1420 }
1421
1422 /* Need more checks? */
1423 if (dp->dad_ns_ocount < dp->dad_count) {
1424 /*
1425 * We have more NS to go. Send NS packet for DAD.
1426 */
1427 nd6_dad_starttimer(dp,
1428 (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1429 nd6_dad_ns_output(dp);
1430 goto done;
1431 } else {
1432 /*
1433 * We have transmitted sufficient number of DAD packets.
1434 * See what we've got.
1435 */
1436 if (dp->dad_ns_icount > 0 || dp->dad_na_icount > 0) {
1437 /* We've seen NS or NA, means DAD has failed. */
1438 nd6_dad_duplicated(ifa, dp);
1439 } else if (V_dad_enhanced != 0 &&
1440 dp->dad_ns_lcount > 0 &&
1441 dp->dad_ns_lcount > dp->dad_loopbackprobe) {
1442 /*
1443 * Sec. 4.1 in RFC 7527 requires transmission of
1444 * additional probes until the loopback condition
1445 * becomes clear when a looped back probe is detected.
1446 */
1447 log(LOG_ERR, "%s: a looped back NS message is "
1448 "detected during DAD for %s. "
1449 "Another DAD probes are being sent.\n",
1450 if_name(ifa->ifa_ifp),
1451 ip6_sprintf(ip6buf, IFA_IN6(ifa)));
1452 dp->dad_loopbackprobe = dp->dad_ns_lcount;
1453 /*
1454 * Send an NS immediately and increase dad_count by
1455 * V_nd6_mmaxtries - 1.
1456 */
1457 dp->dad_count =
1458 dp->dad_ns_ocount + V_nd6_mmaxtries - 1;
1459 nd6_dad_starttimer(dp,
1460 (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
1461 nd6_dad_ns_output(dp);
1462 goto done;
1463 } else {
1464 /*
1465 * We are done with DAD. No NA came, no NS came.
1466 * No duplicate address found. Check IFDISABLED flag
1467 * again in case that it is changed between the
1468 * beginning of this function and here.
1469 */
1470 if ((ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) == 0)
1471 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1472
1473 nd6log((LOG_DEBUG,
1474 "%s: DAD complete for %s - no duplicates found\n",
1475 if_name(ifa->ifa_ifp),
1476 ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr)));
1477 if (dp->dad_ns_lcount > 0)
1478 log(LOG_ERR, "%s: DAD completed while "
1479 "a looped back NS message is detected "
1480 "during DAD for %s.\n",
1481 if_name(ifa->ifa_ifp),
1482 ip6_sprintf(ip6buf, IFA_IN6(ifa)));
1483 }
1484 }
1485 err:
1486 nd6_dad_del(dp);
1487 DADQ_WUNLOCK();
1488 done:
1489 NET_EPOCH_EXIT(et);
1490 CURVNET_RESTORE();
1491 }
1492
1493 static void
nd6_dad_duplicated(struct ifaddr * ifa,struct dadq * dp)1494 nd6_dad_duplicated(struct ifaddr *ifa, struct dadq *dp)
1495 {
1496 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1497 struct ifnet *ifp;
1498 char ip6buf[INET6_ADDRSTRLEN];
1499
1500 log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: "
1501 "NS in/out/loopback=%d/%d/%d, NA in=%d\n",
1502 if_name(ifa->ifa_ifp), ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr),
1503 dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_ns_lcount,
1504 dp->dad_na_icount);
1505
1506 ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1507 ia->ia6_flags |= IN6_IFF_DUPLICATED;
1508
1509 ifp = ifa->ifa_ifp;
1510 log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
1511 if_name(ifp), ip6_sprintf(ip6buf, &ia->ia_addr.sin6_addr));
1512 log(LOG_ERR, "%s: manual intervention required\n",
1513 if_name(ifp));
1514
1515 /*
1516 * If the address is a link-local address formed from an interface
1517 * identifier based on the hardware address which is supposed to be
1518 * uniquely assigned (e.g., EUI-64 for an Ethernet interface), IP
1519 * operation on the interface SHOULD be disabled.
1520 * [RFC 4862, Section 5.4.5]
1521 */
1522 if (IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) {
1523 struct in6_addr in6;
1524
1525 /*
1526 * To avoid over-reaction, we only apply this logic when we are
1527 * very sure that hardware addresses are supposed to be unique.
1528 */
1529 switch (ifp->if_type) {
1530 case IFT_ETHER:
1531 case IFT_ATM:
1532 case IFT_IEEE1394:
1533 case IFT_INFINIBAND:
1534 in6 = ia->ia_addr.sin6_addr;
1535 if (in6_get_hw_ifid(ifp, &in6) == 0 &&
1536 IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr, &in6)) {
1537 ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED;
1538 log(LOG_ERR, "%s: possible hardware address "
1539 "duplication detected, disable IPv6\n",
1540 if_name(ifp));
1541 }
1542 break;
1543 }
1544 }
1545 }
1546
1547 /*
1548 * Transmit a neighbour solicitation for the purpose of DAD. Returns with the
1549 * DAD queue unlocked.
1550 */
1551 static void
nd6_dad_ns_output(struct dadq * dp)1552 nd6_dad_ns_output(struct dadq *dp)
1553 {
1554 struct in6_ifaddr *ia = (struct in6_ifaddr *)dp->dad_ifa;
1555 struct ifnet *ifp = dp->dad_ifa->ifa_ifp;
1556 int i;
1557
1558 DADQ_WLOCK_ASSERT();
1559
1560 dp->dad_ns_tcount++;
1561 if ((ifp->if_flags & IFF_UP) == 0) {
1562 DADQ_WUNLOCK();
1563 return;
1564 }
1565 if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
1566 DADQ_WUNLOCK();
1567 return;
1568 }
1569
1570 dp->dad_ns_ocount++;
1571 if (V_dad_enhanced != 0) {
1572 for (i = 0; i < ND_OPT_NONCE_LEN32; i++)
1573 dp->dad_nonce[i] = arc4random();
1574 /*
1575 * XXXHRS: Note that in the case that
1576 * DupAddrDetectTransmits > 1, multiple NS messages with
1577 * different nonces can be looped back in an unexpected
1578 * order. The current implementation recognizes only
1579 * the latest nonce on the sender side. Practically it
1580 * should work well in almost all cases.
1581 */
1582 }
1583 DADQ_WUNLOCK();
1584 nd6_ns_output(ifp, NULL, NULL, &ia->ia_addr.sin6_addr,
1585 (uint8_t *)&dp->dad_nonce[0]);
1586 }
1587
1588 static void
nd6_dad_ns_input(struct ifaddr * ifa,struct nd_opt_nonce * ndopt_nonce)1589 nd6_dad_ns_input(struct ifaddr *ifa, struct nd_opt_nonce *ndopt_nonce)
1590 {
1591 struct dadq *dp;
1592
1593 if (ifa == NULL)
1594 panic("ifa == NULL in nd6_dad_ns_input");
1595
1596 /* Ignore Nonce option when Enhanced DAD is disabled. */
1597 if (V_dad_enhanced == 0)
1598 ndopt_nonce = NULL;
1599 DADQ_RLOCK();
1600 dp = nd6_dad_find(ifa, ndopt_nonce);
1601 if (dp != NULL)
1602 dp->dad_ns_icount++;
1603 DADQ_RUNLOCK();
1604 }
1605
1606 static void
nd6_dad_na_input(struct ifaddr * ifa)1607 nd6_dad_na_input(struct ifaddr *ifa)
1608 {
1609 struct dadq *dp;
1610
1611 if (ifa == NULL)
1612 panic("ifa == NULL in nd6_dad_na_input");
1613
1614 DADQ_RLOCK();
1615 dp = nd6_dad_find(ifa, NULL);
1616 if (dp != NULL)
1617 dp->dad_na_icount++;
1618 DADQ_RUNLOCK();
1619 }
1620