nd6_nbr.c revision 1.174
1 /* $NetBSD: nd6_nbr.c,v 1.174 2019/09/25 09:52:32 ozaki-r Exp $ */ 2 /* $KAME: nd6_nbr.c,v 1.61 2001/02/10 16:06:14 jinmei Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __KERNEL_RCSID(0, "$NetBSD: nd6_nbr.c,v 1.174 2019/09/25 09:52:32 ozaki-r Exp $"); 35 36 #ifdef _KERNEL_OPT 37 #include "opt_inet.h" 38 #include "opt_net_mpsafe.h" 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/kmem.h> 44 #include <sys/mbuf.h> 45 #include <sys/socket.h> 46 #include <sys/socketvar.h> 47 #include <sys/sockio.h> 48 #include <sys/time.h> 49 #include <sys/kernel.h> 50 #include <sys/errno.h> 51 #include <sys/ioctl.h> 52 #include <sys/syslog.h> 53 #include <sys/queue.h> 54 #include <sys/callout.h> 55 #include <sys/cprng.h> 56 57 #include <net/if.h> 58 #include <net/if_types.h> 59 #include <net/if_dl.h> 60 #include <net/route.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_var.h> 64 #include <netinet6/in6_var.h> 65 #include <netinet6/in6_ifattach.h> 66 #include <netinet/ip6.h> 67 #include <netinet6/ip6_var.h> 68 #include <netinet6/scope6_var.h> 69 #include <netinet6/nd6.h> 70 #include <netinet/icmp6.h> 71 #include <netinet6/icmp6_private.h> 72 73 #include "carp.h" 74 #if NCARP > 0 75 #include <netinet/ip_carp.h> 76 #endif 77 78 struct dadq; 79 static struct dadq *nd6_dad_find(struct ifaddr *, struct nd_opt_nonce *, bool *); 80 static bool nd6_dad_ownnonce(struct ifaddr *, struct nd_opt_nonce *nonce); 81 static void nd6_dad_starttimer(struct dadq *, int); 82 static void nd6_dad_destroytimer(struct dadq *); 83 static void nd6_dad_timer(struct dadq *); 84 static void nd6_dad_ns_output(struct dadq *, struct ifaddr *); 85 static void nd6_dad_input(struct ifaddr *, struct nd_opt_nonce *, 86 const struct sockaddr_dl *); 87 static void nd6_dad_duplicated(struct ifaddr *, struct dadq *, 88 const struct sockaddr_dl *); 89 90 static int dad_maxtry = 15; /* max # of *tries* to transmit DAD packet */ 91 92 /* 93 * Input a Neighbor Solicitation Message. 94 * 95 * Based on RFC 2461 96 * Based on RFC 2462 (duplicate address detection) 97 */ 98 void 99 nd6_ns_input(struct mbuf *m, int off, int icmp6len) 100 { 101 struct ifnet *ifp; 102 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 103 struct nd_neighbor_solicit *nd_ns; 104 struct in6_addr saddr6 = ip6->ip6_src; 105 struct in6_addr daddr6 = ip6->ip6_dst; 106 struct in6_addr taddr6; 107 struct in6_addr myaddr6; 108 char *lladdr = NULL; 109 struct ifaddr *ifa = NULL; 110 int lladdrlen = 0; 111 int anycast = 0, proxy = 0, tentative = 0; 112 int router = ip6_forwarding; 113 int tlladdr; 114 union nd_opts ndopts; 115 const struct sockaddr_dl *proxydl = NULL; 116 struct psref psref; 117 struct psref psref_ia; 118 char ip6buf[INET6_ADDRSTRLEN], ip6buf2[INET6_ADDRSTRLEN]; 119 120 ifp = m_get_rcvif_psref(m, &psref); 121 if (ifp == NULL) 122 goto freeit; 123 124 IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len); 125 if (nd_ns == NULL) { 126 ICMP6_STATINC(ICMP6_STAT_TOOSHORT); 127 m_put_rcvif_psref(ifp, &psref); 128 return; 129 } 130 ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */ 131 taddr6 = nd_ns->nd_ns_target; 132 if (in6_setscope(&taddr6, ifp, NULL) != 0) 133 goto bad; 134 135 if (ip6->ip6_hlim != 255) { 136 nd6log(LOG_ERR, "invalid hlim (%d) from %s to %s on %s\n", 137 ip6->ip6_hlim, IN6_PRINT(ip6buf, &ip6->ip6_src), 138 IN6_PRINT(ip6buf2, &ip6->ip6_dst), if_name(ifp)); 139 goto bad; 140 } 141 142 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) { 143 /* dst has to be a solicited node multicast address. */ 144 /* don't check ifindex portion */ 145 if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL && 146 daddr6.s6_addr32[1] == 0 && 147 daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE && 148 daddr6.s6_addr8[12] == 0xff) { 149 ; /* good */ 150 } else { 151 nd6log(LOG_INFO, "bad DAD packet (wrong ip6 dst)\n"); 152 goto bad; 153 } 154 } else { 155 struct sockaddr_in6 ssin6; 156 157 /* 158 * Make sure the source address is from a neighbor's address. 159 */ 160 sockaddr_in6_init(&ssin6, &saddr6, 0, 0, 0); 161 if (nd6_is_addr_neighbor(&ssin6, ifp) == 0) { 162 nd6log(LOG_INFO, 163 "NS packet from non-neighbor %s on %s\n", 164 IN6_PRINT(ip6buf, &saddr6), if_name(ifp)); 165 goto bad; 166 } 167 } 168 169 if (IN6_IS_ADDR_MULTICAST(&taddr6)) { 170 nd6log(LOG_INFO, "bad NS target (multicast)\n"); 171 goto bad; 172 } 173 174 icmp6len -= sizeof(*nd_ns); 175 nd6_option_init(nd_ns + 1, icmp6len, &ndopts); 176 if (nd6_options(&ndopts) < 0) { 177 nd6log(LOG_INFO, "invalid ND option, ignored\n"); 178 /* nd6_options have incremented stats */ 179 goto freeit; 180 } 181 182 if (ndopts.nd_opts_src_lladdr) { 183 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1); 184 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3; 185 } 186 187 if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) { 188 nd6log(LOG_INFO, 189 "bad DAD packet (link-layer address option)\n"); 190 goto bad; 191 } 192 193 /* 194 * Attaching target link-layer address to the NA? 195 * (RFC 2461 7.2.4) 196 * 197 * NS IP dst is multicast MUST add 198 * Otherwise MAY be omitted 199 * 200 * In this implementation, we omit the target link-layer address 201 * in the "MAY" case. 202 */ 203 #if 0 /* too much! */ 204 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6); 205 if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST)) 206 tlladdr = 0; 207 else 208 #endif 209 if (!IN6_IS_ADDR_MULTICAST(&daddr6)) 210 tlladdr = 0; 211 else 212 tlladdr = 1; 213 214 /* 215 * Target address (taddr6) must be either: 216 * (1) Valid unicast/anycast address for my receiving interface, 217 * (2) Unicast address for which I'm offering proxy service, or 218 * (3) "tentative" address on which DAD is being performed. 219 */ 220 /* (1) and (3) check. */ 221 #if NCARP > 0 222 if (ifp->if_carp && ifp->if_type != IFT_CARP) { 223 int s = pserialize_read_enter(); 224 ifa = carp_iamatch6(ifp->if_carp, &taddr6); 225 if (ifa != NULL) 226 ifa_acquire(ifa, &psref_ia); 227 pserialize_read_exit(s); 228 } else 229 ifa = NULL; 230 if (!ifa) 231 ifa = (struct ifaddr *)in6ifa_ifpwithaddr_psref(ifp, &taddr6, 232 &psref_ia); 233 #else 234 ifa = (struct ifaddr *)in6ifa_ifpwithaddr_psref(ifp, &taddr6, 235 &psref_ia); 236 #endif 237 238 /* (2) check. */ 239 if (ifa == NULL) { 240 struct rtentry *rt; 241 struct sockaddr_in6 tsin6; 242 243 sockaddr_in6_init(&tsin6, &taddr6, 0, 0, 0); 244 245 rt = rtalloc1(sin6tosa(&tsin6), 0); 246 if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 && 247 rt->rt_gateway->sa_family == AF_LINK) { 248 /* 249 * proxy NDP for single entry 250 */ 251 ifa = (struct ifaddr *)in6ifa_ifpforlinklocal_psref(ifp, 252 IN6_IFF_NOTREADY|IN6_IFF_ANYCAST, &psref_ia); 253 if (ifa) { 254 proxy = 1; 255 proxydl = satocsdl(rt->rt_gateway); 256 router = 0; /* XXX */ 257 } 258 } 259 if (rt) 260 rt_unref(rt); 261 } 262 if (ifa == NULL) { 263 /* 264 * We've got an NS packet, and we don't have that address 265 * assigned for us. We MUST silently ignore it. 266 * See RFC2461 7.2.3. 267 */ 268 goto freeit; 269 } 270 myaddr6 = *IFA_IN6(ifa); 271 anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST; 272 tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE; 273 if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED) 274 goto freeit; 275 276 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) { 277 nd6log(LOG_INFO, "lladdrlen mismatch for %s " 278 "(if %d, NS packet %d)\n", 279 IN6_PRINT(ip6buf, &taddr6), 280 ifp->if_addrlen, lladdrlen - 2); 281 goto bad; 282 } 283 284 if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) { 285 nd6log(LOG_INFO, "duplicate IP6 address %s\n", 286 IN6_PRINT(ip6buf, &saddr6)); 287 goto freeit; 288 } 289 290 /* 291 * We have neighbor solicitation packet, with target address equals to 292 * one of my tentative address. 293 * 294 * src addr how to process? 295 * --- --- 296 * multicast of course, invalid (rejected in ip6_input) 297 * unicast somebody is doing address resolution -> ignore 298 * unspec dup address detection 299 * 300 * The processing is defined in RFC 2462. 301 */ 302 if (tentative) { 303 /* 304 * If source address is unspecified address, it is for 305 * duplicate address detection. 306 * 307 * If not, the packet is for addess resolution; 308 * silently ignore it. 309 */ 310 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) { 311 struct sockaddr_dl sdl, *sdlp; 312 313 if (lladdr != NULL) 314 sdlp = sockaddr_dl_init(&sdl, sizeof(sdl), 315 ifp->if_index, ifp->if_type, 316 NULL, 0, lladdr, lladdrlen); 317 else 318 sdlp = NULL; 319 nd6_dad_input(ifa, ndopts.nd_opts_nonce, sdlp); 320 } 321 goto freeit; 322 } 323 324 /* 325 * It looks that sender is performing DAD. 326 * Check that the nonce is not being used by the same address 327 * on another interface. 328 */ 329 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6) && ndopts.nd_opts_nonce != NULL) { 330 if (nd6_dad_ownnonce(ifa, ndopts.nd_opts_nonce)) 331 goto freeit; 332 } 333 334 ifa_release(ifa, &psref_ia); 335 ifa = NULL; 336 337 /* 338 * If the source address is unspecified address, entries must not 339 * be created or updated. 340 * It looks that sender is performing DAD. Output NA toward 341 * all-node multicast address, to tell the sender that I'm using 342 * the address. 343 * S bit ("solicited") must be zero. 344 */ 345 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) { 346 struct in6_addr in6_all; 347 348 in6_all = in6addr_linklocal_allnodes; 349 if (in6_setscope(&in6_all, ifp, NULL) != 0) 350 goto bad; 351 nd6_na_output(ifp, &in6_all, &taddr6, 352 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) | 353 (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0), 354 tlladdr, (const struct sockaddr *)proxydl); 355 goto freeit; 356 } 357 358 nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0); 359 360 nd6_na_output(ifp, &saddr6, &taddr6, 361 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) | 362 (router ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED, 363 tlladdr, (const struct sockaddr *)proxydl); 364 freeit: 365 ifa_release(ifa, &psref_ia); 366 m_put_rcvif_psref(ifp, &psref); 367 m_freem(m); 368 return; 369 370 bad: 371 nd6log(LOG_ERR, "src=%s\n", IN6_PRINT(ip6buf, &saddr6)); 372 nd6log(LOG_ERR, "dst=%s\n", IN6_PRINT(ip6buf, &daddr6)); 373 nd6log(LOG_ERR, "tgt=%s\n", IN6_PRINT(ip6buf, &taddr6)); 374 ICMP6_STATINC(ICMP6_STAT_BADNS); 375 ifa_release(ifa, &psref_ia); 376 m_put_rcvif_psref(ifp, &psref); 377 m_freem(m); 378 } 379 380 /* 381 * Output a Neighbor Solicitation Message. Caller specifies: 382 * - ICMP6 header source IP6 address 383 * - ND6 header target IP6 address 384 * - ND6 header source datalink address 385 * 386 * Based on RFC 2461 387 * Based on RFC 2462 (duplicate address detection) 388 */ 389 void 390 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *daddr6, 391 const struct in6_addr *taddr6, 392 struct in6_addr *hsrc, 393 uint8_t *nonce /* duplicate address detection */) 394 { 395 struct mbuf *m; 396 struct ip6_hdr *ip6; 397 struct nd_neighbor_solicit *nd_ns; 398 struct in6_addr *src, src_in; 399 struct ip6_moptions im6o; 400 int icmp6len; 401 int maxlen; 402 const void *mac; 403 struct route ro; 404 405 if (IN6_IS_ADDR_MULTICAST(taddr6)) 406 return; 407 408 memset(&ro, 0, sizeof(ro)); 409 410 /* estimate the size of message */ 411 maxlen = sizeof(*ip6) + sizeof(*nd_ns); 412 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7; 413 KASSERTMSG(max_linkhdr + maxlen <= MCLBYTES, 414 "max_linkhdr + maxlen > MCLBYTES (%d + %d > %d)", 415 max_linkhdr, maxlen, MCLBYTES); 416 417 MGETHDR(m, M_DONTWAIT, MT_DATA); 418 if (m && max_linkhdr + maxlen >= MHLEN) { 419 MCLGET(m, M_DONTWAIT); 420 if ((m->m_flags & M_EXT) == 0) { 421 m_free(m); 422 m = NULL; 423 } 424 } 425 if (m == NULL) 426 return; 427 m_reset_rcvif(m); 428 429 if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) { 430 m->m_flags |= M_MCAST; 431 im6o.im6o_multicast_if_index = if_get_index(ifp); 432 im6o.im6o_multicast_hlim = 255; 433 im6o.im6o_multicast_loop = 0; 434 } 435 436 icmp6len = sizeof(*nd_ns); 437 m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len; 438 m->m_data += max_linkhdr; /* or m_align() equivalent? */ 439 440 /* fill neighbor solicitation packet */ 441 ip6 = mtod(m, struct ip6_hdr *); 442 ip6->ip6_flow = 0; 443 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 444 ip6->ip6_vfc |= IPV6_VERSION; 445 /* ip6->ip6_plen will be set later */ 446 ip6->ip6_nxt = IPPROTO_ICMPV6; 447 ip6->ip6_hlim = 255; 448 if (daddr6) 449 ip6->ip6_dst = *daddr6; 450 else { 451 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL; 452 ip6->ip6_dst.s6_addr16[1] = 0; 453 ip6->ip6_dst.s6_addr32[1] = 0; 454 ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE; 455 ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3]; 456 ip6->ip6_dst.s6_addr8[12] = 0xff; 457 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0) 458 goto bad; 459 } 460 if (nonce == NULL) { 461 int s; 462 /* 463 * RFC2461 7.2.2: 464 * "If the source address of the packet prompting the 465 * solicitation is the same as one of the addresses assigned 466 * to the outgoing interface, that address SHOULD be placed 467 * in the IP Source Address of the outgoing solicitation. 468 * Otherwise, any one of the addresses assigned to the 469 * interface should be used." 470 * 471 * We use the source address for the prompting packet 472 * (hsrc), if: 473 * - hsrc is given from the caller (by giving "ln"), and 474 * - hsrc belongs to the outgoing interface. 475 * Otherwise, we perform the source address selection as usual. 476 */ 477 s = pserialize_read_enter(); 478 if (hsrc && in6ifa_ifpwithaddr(ifp, hsrc)) { 479 pserialize_read_exit(s); 480 src = hsrc; 481 } else { 482 int error; 483 struct sockaddr_in6 dst_sa; 484 485 pserialize_read_exit(s); 486 487 sockaddr_in6_init(&dst_sa, &ip6->ip6_dst, 0, 0, 0); 488 489 error = in6_selectsrc(&dst_sa, NULL, 490 NULL, &ro, NULL, NULL, NULL, &src_in); 491 if (error != 0) { 492 char ip6buf[INET6_ADDRSTRLEN]; 493 nd6log(LOG_DEBUG, "source can't be " 494 "determined: dst=%s, error=%d\n", 495 IN6_PRINT(ip6buf, &dst_sa.sin6_addr), 496 error); 497 goto bad; 498 } 499 src = &src_in; 500 } 501 } else { 502 /* 503 * Source address for DAD packet must always be IPv6 504 * unspecified address. (0::0) 505 * We actually don't have to 0-clear the address (we did it 506 * above), but we do so here explicitly to make the intention 507 * clearer. 508 */ 509 memset(&src_in, 0, sizeof(src_in)); 510 src = &src_in; 511 } 512 ip6->ip6_src = *src; 513 nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1); 514 nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT; 515 nd_ns->nd_ns_code = 0; 516 nd_ns->nd_ns_reserved = 0; 517 nd_ns->nd_ns_target = *taddr6; 518 in6_clearscope(&nd_ns->nd_ns_target); /* XXX */ 519 520 /* 521 * Add source link-layer address option. 522 * 523 * spec implementation 524 * --- --- 525 * DAD packet MUST NOT do not add the option 526 * there's no link layer address: 527 * impossible do not add the option 528 * there's link layer address: 529 * Multicast NS MUST add one add the option 530 * Unicast NS SHOULD add one add the option 531 */ 532 if (nonce == NULL && (mac = nd6_ifptomac(ifp))) { 533 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen; 534 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1); 535 /* 8 byte alignments... */ 536 optlen = (optlen + 7) & ~7; 537 538 m->m_pkthdr.len += optlen; 539 m->m_len += optlen; 540 icmp6len += optlen; 541 memset((void *)nd_opt, 0, optlen); 542 nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; 543 nd_opt->nd_opt_len = optlen >> 3; 544 memcpy((void *)(nd_opt + 1), mac, ifp->if_addrlen); 545 } 546 547 /* Add a nonce option (RFC 3971) to detect looped back NS messages. 548 * This behavior is documented in RFC 7527. */ 549 if (nonce != NULL) { 550 int optlen = sizeof(struct nd_opt_hdr) + ND_OPT_NONCE_LEN; 551 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1); 552 553 /* 8-byte alignment is required. */ 554 optlen = (optlen + 7) & ~7; 555 m->m_pkthdr.len += optlen; 556 m->m_len += optlen; 557 icmp6len += optlen; 558 memset(nd_opt, 0, optlen); 559 nd_opt->nd_opt_type = ND_OPT_NONCE; 560 nd_opt->nd_opt_len = optlen >> 3; 561 memcpy(nd_opt + 1, nonce, ND_OPT_NONCE_LEN); 562 } 563 564 ip6->ip6_plen = htons((u_int16_t)icmp6len); 565 nd_ns->nd_ns_cksum = 0; 566 nd_ns->nd_ns_cksum = 567 in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len); 568 569 ip6_output(m, NULL, &ro, nonce != NULL ? IPV6_UNSPECSRC : 0, 570 &im6o, NULL, NULL); 571 icmp6_ifstat_inc(ifp, ifs6_out_msg); 572 icmp6_ifstat_inc(ifp, ifs6_out_neighborsolicit); 573 ICMP6_STATINC(ICMP6_STAT_OUTHIST + ND_NEIGHBOR_SOLICIT); 574 575 rtcache_free(&ro); 576 return; 577 578 bad: 579 rtcache_free(&ro); 580 m_freem(m); 581 return; 582 } 583 584 /* 585 * Neighbor advertisement input handling. 586 * 587 * Based on RFC 2461 588 * Based on RFC 2462 (duplicate address detection) 589 * 590 * the following items are not implemented yet: 591 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD) 592 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD) 593 */ 594 void 595 nd6_na_input(struct mbuf *m, int off, int icmp6len) 596 { 597 struct ifnet *ifp; 598 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 599 struct nd_neighbor_advert *nd_na; 600 struct in6_addr saddr6 = ip6->ip6_src; 601 struct in6_addr daddr6 = ip6->ip6_dst; 602 struct in6_addr taddr6; 603 int flags; 604 int is_router; 605 int is_solicited; 606 int is_override; 607 int rt_cmd; 608 char *lladdr = NULL; 609 int lladdrlen = 0; 610 struct ifaddr *ifa; 611 struct llentry *ln = NULL; 612 union nd_opts ndopts; 613 struct sockaddr_in6 ssin6; 614 bool checklink = false; 615 struct psref psref; 616 struct psref psref_ia; 617 char ip6buf[INET6_ADDRSTRLEN], ip6buf2[INET6_ADDRSTRLEN]; 618 619 ifp = m_get_rcvif_psref(m, &psref); 620 if (ifp == NULL) 621 goto freeit; 622 623 if (ip6->ip6_hlim != 255) { 624 nd6log(LOG_ERR, 625 "invalid hlim (%d) from %s to %s on %s\n", 626 ip6->ip6_hlim, IN6_PRINT(ip6buf, &ip6->ip6_src), 627 IN6_PRINT(ip6buf2, &ip6->ip6_dst), if_name(ifp)); 628 goto bad; 629 } 630 631 IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len); 632 if (nd_na == NULL) { 633 m_put_rcvif_psref(ifp, &psref); 634 ICMP6_STATINC(ICMP6_STAT_TOOSHORT); 635 return; 636 } 637 638 flags = nd_na->nd_na_flags_reserved; 639 is_router = ((flags & ND_NA_FLAG_ROUTER) != 0); 640 is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0); 641 is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0); 642 643 taddr6 = nd_na->nd_na_target; 644 if (in6_setscope(&taddr6, ifp, NULL)) { 645 goto bad; 646 } 647 648 if (IN6_IS_ADDR_MULTICAST(&taddr6)) { 649 nd6log(LOG_ERR, "invalid target address %s\n", 650 IN6_PRINT(ip6buf, &taddr6)); 651 goto bad; 652 } 653 if (is_solicited && IN6_IS_ADDR_MULTICAST(&daddr6)) { 654 nd6log(LOG_ERR, "a solicited adv is multicasted\n"); 655 goto bad; 656 } 657 658 icmp6len -= sizeof(*nd_na); 659 nd6_option_init(nd_na + 1, icmp6len, &ndopts); 660 if (nd6_options(&ndopts) < 0) { 661 nd6log(LOG_INFO, "invalid ND option, ignored\n"); 662 /* nd6_options have incremented stats */ 663 goto freeit; 664 } 665 666 if (ndopts.nd_opts_tgt_lladdr != NULL) { 667 struct ifnet *ifp_ll; 668 struct psref psref_ll; 669 670 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1); 671 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3; 672 673 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) { 674 nd6log(LOG_INFO, "lladdrlen mismatch for %s " 675 "(if %d, NA packet %d)\n", IN6_PRINT(ip6buf, &taddr6), 676 ifp->if_addrlen, lladdrlen - 2); 677 goto bad; 678 } 679 680 ifp_ll = if_get_bylla(lladdr, ifp->if_addrlen, &psref_ll); 681 if (ifp_ll != NULL) { 682 /* it's from me, ignore it. */ 683 if_put(ifp_ll, &psref_ll); 684 goto freeit; 685 } 686 } 687 688 ifa = (struct ifaddr *)in6ifa_ifpwithaddr_psref(ifp, &taddr6, &psref_ia); 689 690 /* 691 * Target address matches one of my interface address. 692 * 693 * If my address is tentative, this means that there's somebody 694 * already using the same address as mine. This indicates DAD failure. 695 * This is defined in RFC 2462. 696 * 697 * Otherwise, process as defined in RFC 2461. 698 */ 699 if (ifa) { 700 if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE) { 701 struct sockaddr_dl sdl, *sdlp; 702 703 if (lladdr != NULL) 704 sdlp = sockaddr_dl_init(&sdl, sizeof(sdl), 705 ifp->if_index, ifp->if_type, 706 NULL, 0, lladdr, lladdrlen); 707 else 708 sdlp = NULL; 709 nd6_dad_input(ifa, NULL, sdlp); 710 } else 711 log(LOG_ERR, 712 "nd6_na_input: duplicate IP6 address %s\n", 713 IN6_PRINT(ip6buf, &taddr6)); 714 ifa_release(ifa, &psref_ia); 715 ifa = NULL; 716 goto freeit; 717 } 718 719 /* 720 * Make sure the source address is from a neighbor's address. 721 */ 722 sockaddr_in6_init(&ssin6, &saddr6, 0, 0, 0); 723 if (nd6_is_addr_neighbor(&ssin6, ifp) == 0) { 724 nd6log(LOG_INFO, "ND packet from non-neighbor %s on %s\n", 725 IN6_PRINT(ip6buf, &saddr6), if_name(ifp)); 726 goto bad; 727 } 728 729 /* 730 * If no neighbor cache entry is found, NA SHOULD silently be 731 * discarded. 732 */ 733 ln = nd6_lookup(&taddr6, ifp, true); 734 if (ln == NULL) 735 goto freeit; 736 737 rt_cmd = 0; 738 if (ln->ln_state == ND6_LLINFO_INCOMPLETE) { 739 /* 740 * If the link-layer has address, and no lladdr option came, 741 * discard the packet. 742 */ 743 if (ifp->if_addrlen && !lladdr) 744 goto freeit; 745 746 /* 747 * Record link-layer address, and update the state. 748 */ 749 memcpy(&ln->ll_addr, lladdr, ifp->if_addrlen); 750 ln->la_flags |= LLE_VALID; 751 rt_cmd = RTM_ADD; 752 if (is_solicited) { 753 ln->ln_state = ND6_LLINFO_REACHABLE; 754 ln->ln_byhint = 0; 755 if (!ND6_LLINFO_PERMANENT(ln)) { 756 nd6_llinfo_settimer(ln, 757 ND_IFINFO(ln->lle_tbl->llt_ifp)->reachable * hz); 758 } 759 } else { 760 ln->ln_state = ND6_LLINFO_STALE; 761 nd6_llinfo_settimer(ln, nd6_gctimer * hz); 762 } 763 if ((ln->ln_router = is_router) != 0) { 764 /* 765 * This means a router's state has changed from 766 * non-reachable to probably reachable, and might 767 * affect the status of associated prefixes.. 768 */ 769 checklink = true; 770 } 771 } else { 772 bool llchange; 773 774 /* 775 * Check if the link-layer address has changed or not. 776 */ 777 if (lladdr == NULL) 778 llchange = false; 779 else { 780 if (ln->la_flags & LLE_VALID) { 781 if (memcmp(lladdr, &ln->ll_addr, ifp->if_addrlen)) 782 llchange = true; 783 else 784 llchange = false; 785 } else 786 llchange = true; 787 } 788 if (llchange) 789 rt_cmd = RTM_CHANGE; 790 791 /* 792 * This is VERY complex. Look at it with care. 793 * 794 * override solicit lladdr llchange action 795 * (L: record lladdr) 796 * 797 * 0 0 n -- (2c) 798 * 0 0 y n (2b) L 799 * 0 0 y y (1) REACHABLE->STALE 800 * 0 1 n -- (2c) *->REACHABLE 801 * 0 1 y n (2b) L *->REACHABLE 802 * 0 1 y y (1) REACHABLE->STALE 803 * 1 0 n -- (2a) 804 * 1 0 y n (2a) L 805 * 1 0 y y (2a) L *->STALE 806 * 1 1 n -- (2a) *->REACHABLE 807 * 1 1 y n (2a) L *->REACHABLE 808 * 1 1 y y (2a) L *->REACHABLE 809 */ 810 if (!is_override && lladdr != NULL && llchange) { /* (1) */ 811 /* 812 * If state is REACHABLE, make it STALE. 813 * no other updates should be done. 814 */ 815 if (ln->ln_state == ND6_LLINFO_REACHABLE) { 816 ln->ln_state = ND6_LLINFO_STALE; 817 nd6_llinfo_settimer(ln, nd6_gctimer * hz); 818 } 819 goto freeit; 820 } else if (is_override /* (2a) */ 821 || (!is_override && lladdr != NULL && !llchange) /* (2b) */ 822 || lladdr == NULL) { /* (2c) */ 823 /* 824 * Update link-local address, if any. 825 */ 826 if (lladdr != NULL) { 827 memcpy(&ln->ll_addr, lladdr, ifp->if_addrlen); 828 ln->la_flags |= LLE_VALID; 829 } 830 831 /* 832 * If solicited, make the state REACHABLE. 833 * If not solicited and the link-layer address was 834 * changed, make it STALE. 835 */ 836 if (is_solicited) { 837 ln->ln_state = ND6_LLINFO_REACHABLE; 838 ln->ln_byhint = 0; 839 if (!ND6_LLINFO_PERMANENT(ln)) { 840 nd6_llinfo_settimer(ln, 841 ND_IFINFO(ifp)->reachable * hz); 842 } 843 } else { 844 if (lladdr && llchange) { 845 ln->ln_state = ND6_LLINFO_STALE; 846 nd6_llinfo_settimer(ln, 847 nd6_gctimer * hz); 848 } 849 } 850 } 851 852 if (ln->ln_router && !is_router) { 853 /* 854 * The peer dropped the router flag. 855 * Remove the sender from the Default Router List and 856 * update the Destination Cache entries. 857 */ 858 const struct in6_addr *in6 = &ln->r_l3addr.addr6; 859 struct nd_defrouter *dr; 860 861 ND6_WLOCK(); 862 dr = nd6_defrouter_lookup(in6, ln->lle_tbl->llt_ifp); 863 if (dr) 864 nd6_defrtrlist_del(dr, NULL); 865 else if (!ip6_forwarding) { 866 /* 867 * Even if the neighbor is not in the default 868 * router list, the neighbor may be used 869 * as a next hop for some destinations 870 * (e.g. redirect case). So we must 871 * call nd6_rt_flush explicitly. 872 */ 873 nd6_rt_flush(&ip6->ip6_src, ln->lle_tbl->llt_ifp); 874 } 875 ND6_UNLOCK(); 876 } 877 ln->ln_router = is_router; 878 } 879 /* 880 * XXX: does this matter? 881 * rt->rt_flags &= ~RTF_REJECT; 882 */ 883 ln->ln_asked = 0; 884 nd6_llinfo_release_pkts(ln, ifp); 885 886 if (rt_cmd != 0) { 887 struct sockaddr_in6 sin6; 888 889 sockaddr_in6_init(&sin6, &ln->r_l3addr.addr6, 0, 0, 0); 890 rt_clonedmsg(rt_cmd, sin6tosa(&sin6), 891 (char *)&ln->ll_addr, ln->lle_tbl->llt_ifp); 892 } 893 894 freeit: 895 if (ln != NULL) 896 LLE_WUNLOCK(ln); 897 898 if (checklink) { 899 ND6_WLOCK(); 900 nd6_pfxlist_onlink_check(); 901 ND6_UNLOCK(); 902 } 903 904 m_put_rcvif_psref(ifp, &psref); 905 m_freem(m); 906 return; 907 908 bad: 909 if (ln != NULL) 910 LLE_WUNLOCK(ln); 911 912 ICMP6_STATINC(ICMP6_STAT_BADNA); 913 m_put_rcvif_psref(ifp, &psref); 914 m_freem(m); 915 } 916 917 /* 918 * Neighbor advertisement output handling. 919 * 920 * Based on RFC 2461 921 * 922 * the following items are not implemented yet: 923 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD) 924 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD) 925 */ 926 void 927 nd6_na_output( 928 struct ifnet *ifp, 929 const struct in6_addr *daddr6_0, 930 const struct in6_addr *taddr6, 931 u_long flags, 932 int tlladdr, /* 1 if include target link-layer address */ 933 const struct sockaddr *sdl0) /* sockaddr_dl (= proxy NA) or NULL */ 934 { 935 struct mbuf *m; 936 struct ip6_hdr *ip6; 937 struct nd_neighbor_advert *nd_na; 938 struct ip6_moptions im6o; 939 struct sockaddr *dst; 940 union { 941 struct sockaddr dst; 942 struct sockaddr_in6 dst6; 943 } u; 944 struct in6_addr daddr6; 945 int icmp6len, maxlen, error; 946 const void *mac; 947 struct route ro; 948 949 mac = NULL; 950 memset(&ro, 0, sizeof(ro)); 951 952 daddr6 = *daddr6_0; /* make a local copy for modification */ 953 954 /* estimate the size of message */ 955 maxlen = sizeof(*ip6) + sizeof(*nd_na); 956 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7; 957 KASSERTMSG(max_linkhdr + maxlen <= MCLBYTES, 958 "max_linkhdr + maxlen > MCLBYTES (%d + %d > %d)", 959 max_linkhdr, maxlen, MCLBYTES); 960 961 MGETHDR(m, M_DONTWAIT, MT_DATA); 962 if (m && max_linkhdr + maxlen >= MHLEN) { 963 MCLGET(m, M_DONTWAIT); 964 if ((m->m_flags & M_EXT) == 0) { 965 m_free(m); 966 m = NULL; 967 } 968 } 969 if (m == NULL) 970 return; 971 m_reset_rcvif(m); 972 973 if (IN6_IS_ADDR_MULTICAST(&daddr6)) { 974 m->m_flags |= M_MCAST; 975 im6o.im6o_multicast_if_index = if_get_index(ifp); 976 im6o.im6o_multicast_hlim = 255; 977 im6o.im6o_multicast_loop = 0; 978 } 979 980 icmp6len = sizeof(*nd_na); 981 m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len; 982 m->m_data += max_linkhdr; /* or m_align() equivalent? */ 983 984 /* fill neighbor advertisement packet */ 985 ip6 = mtod(m, struct ip6_hdr *); 986 ip6->ip6_flow = 0; 987 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 988 ip6->ip6_vfc |= IPV6_VERSION; 989 ip6->ip6_nxt = IPPROTO_ICMPV6; 990 ip6->ip6_hlim = 255; 991 if (IN6_IS_ADDR_UNSPECIFIED(&daddr6)) { 992 /* reply to DAD */ 993 daddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL; 994 daddr6.s6_addr16[1] = 0; 995 daddr6.s6_addr32[1] = 0; 996 daddr6.s6_addr32[2] = 0; 997 daddr6.s6_addr32[3] = IPV6_ADDR_INT32_ONE; 998 if (in6_setscope(&daddr6, ifp, NULL)) 999 goto bad; 1000 1001 flags &= ~ND_NA_FLAG_SOLICITED; 1002 } 1003 ip6->ip6_dst = daddr6; 1004 sockaddr_in6_init(&u.dst6, &daddr6, 0, 0, 0); 1005 dst = &u.dst; 1006 if (rtcache_setdst(&ro, dst) != 0) 1007 goto bad; 1008 1009 /* 1010 * Select a source whose scope is the same as that of the dest. 1011 */ 1012 error = in6_selectsrc(satosin6(dst), NULL, NULL, &ro, NULL, NULL, NULL, 1013 &ip6->ip6_src); 1014 if (error != 0) { 1015 char ip6buf[INET6_ADDRSTRLEN]; 1016 nd6log(LOG_DEBUG, "source can't be " 1017 "determined: dst=%s, error=%d\n", 1018 IN6_PRINT(ip6buf, &satocsin6(dst)->sin6_addr), error); 1019 goto bad; 1020 } 1021 nd_na = (struct nd_neighbor_advert *)(ip6 + 1); 1022 nd_na->nd_na_type = ND_NEIGHBOR_ADVERT; 1023 nd_na->nd_na_code = 0; 1024 nd_na->nd_na_target = *taddr6; 1025 in6_clearscope(&nd_na->nd_na_target); /* XXX */ 1026 1027 /* 1028 * "tlladdr" indicates NS's condition for adding tlladdr or not. 1029 * see nd6_ns_input() for details. 1030 * Basically, if NS packet is sent to unicast/anycast addr, 1031 * target lladdr option SHOULD NOT be included. 1032 */ 1033 if (tlladdr) { 1034 /* 1035 * sdl0 != NULL indicates proxy NA. If we do proxy, use 1036 * lladdr in sdl0. If we are not proxying (sending NA for 1037 * my address) use lladdr configured for the interface. 1038 */ 1039 if (sdl0 == NULL) 1040 mac = nd6_ifptomac(ifp); 1041 else if (sdl0->sa_family == AF_LINK) { 1042 const struct sockaddr_dl *sdl; 1043 sdl = satocsdl(sdl0); 1044 if (sdl->sdl_alen == ifp->if_addrlen) 1045 mac = CLLADDR(sdl); 1046 } 1047 } 1048 if (tlladdr && mac) { 1049 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen; 1050 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1); 1051 1052 /* roundup to 8 bytes alignment! */ 1053 optlen = (optlen + 7) & ~7; 1054 1055 m->m_pkthdr.len += optlen; 1056 m->m_len += optlen; 1057 icmp6len += optlen; 1058 memset((void *)nd_opt, 0, optlen); 1059 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR; 1060 nd_opt->nd_opt_len = optlen >> 3; 1061 memcpy((void *)(nd_opt + 1), mac, ifp->if_addrlen); 1062 } else 1063 flags &= ~ND_NA_FLAG_OVERRIDE; 1064 1065 ip6->ip6_plen = htons((u_int16_t)icmp6len); 1066 nd_na->nd_na_flags_reserved = flags; 1067 nd_na->nd_na_cksum = 0; 1068 nd_na->nd_na_cksum = 1069 in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len); 1070 1071 ip6_output(m, NULL, NULL, 0, &im6o, NULL, NULL); 1072 1073 icmp6_ifstat_inc(ifp, ifs6_out_msg); 1074 icmp6_ifstat_inc(ifp, ifs6_out_neighboradvert); 1075 ICMP6_STATINC(ICMP6_STAT_OUTHIST + ND_NEIGHBOR_ADVERT); 1076 1077 rtcache_free(&ro); 1078 return; 1079 1080 bad: 1081 rtcache_free(&ro); 1082 m_freem(m); 1083 return; 1084 } 1085 1086 const void * 1087 nd6_ifptomac(const struct ifnet *ifp) 1088 { 1089 switch (ifp->if_type) { 1090 case IFT_ARCNET: 1091 case IFT_ETHER: 1092 case IFT_FDDI: 1093 case IFT_IEEE1394: 1094 case IFT_PROPVIRTUAL: 1095 case IFT_CARP: 1096 case IFT_L2VLAN: 1097 case IFT_IEEE80211: 1098 return CLLADDR(ifp->if_sadl); 1099 default: 1100 return NULL; 1101 } 1102 } 1103 1104 TAILQ_HEAD(dadq_head, dadq); 1105 struct dadq { 1106 TAILQ_ENTRY(dadq) dad_list; 1107 struct ifaddr *dad_ifa; 1108 int dad_count; /* max NS to send */ 1109 int dad_ns_tcount; /* # of trials to send NS */ 1110 int dad_ns_ocount; /* NS sent so far */ 1111 int dad_ns_lcount; /* looped back NS */ 1112 struct callout dad_timer_ch; 1113 #define ND_OPT_NONCE_STORE 3 /* dad_count should not exceed this */ 1114 /* 1115 * The default ip6_dad_count is 1 as specified by RFC 4862 and 1116 * practically must users won't exceed this. 1117 * A storage of 3 is defaulted to here, in-case the administrator wants 1118 * to match the equivalent behaviour in our ARP implementation. 1119 * This constraint could be removed by sending the on wire nonce as 1120 * hmac(key, dad_ns_ocount), but that would increase the nonce size 1121 * sent on the wire. 1122 */ 1123 uint8_t dad_nonce[ND_OPT_NONCE_STORE][ND_OPT_NONCE_LEN]; 1124 }; 1125 1126 static struct dadq_head dadq; 1127 static kmutex_t nd6_dad_lock; 1128 1129 void 1130 nd6_nbr_init(void) 1131 { 1132 1133 TAILQ_INIT(&dadq); 1134 mutex_init(&nd6_dad_lock, MUTEX_DEFAULT, IPL_NONE); 1135 } 1136 1137 static struct dadq * 1138 nd6_dad_find(struct ifaddr *ifa, struct nd_opt_nonce *nonce, bool *found_nonce) 1139 { 1140 struct in6_addr *myaddr6, *dadaddr6; 1141 bool match_ifa; 1142 struct dadq *dp; 1143 int i, nonce_max; 1144 1145 KASSERT(mutex_owned(&nd6_dad_lock)); 1146 KASSERT(ifa != NULL); 1147 1148 myaddr6 = IFA_IN6(ifa); 1149 if (nonce != NULL && 1150 nonce->nd_opt_nonce_len != (ND_OPT_NONCE_LEN + 2) / 8) 1151 nonce = NULL; 1152 match_ifa = nonce == NULL || found_nonce == NULL || *found_nonce == false; 1153 if (found_nonce != NULL) 1154 *found_nonce = false; 1155 1156 TAILQ_FOREACH(dp, &dadq, dad_list) { 1157 if (match_ifa) { 1158 if (dp->dad_ifa != ifa) 1159 continue; 1160 } else { 1161 dadaddr6 = IFA_IN6(dp->dad_ifa); 1162 if (!IN6_ARE_ADDR_EQUAL(myaddr6, dadaddr6)) 1163 continue; 1164 } 1165 1166 if (nonce == NULL) 1167 break; 1168 1169 nonce_max = MIN(dp->dad_ns_ocount, ND_OPT_NONCE_STORE); 1170 for (i = 0; i < nonce_max; i++) { 1171 if (memcmp(nonce->nd_opt_nonce, 1172 dp->dad_nonce[i], 1173 ND_OPT_NONCE_LEN) == 0) 1174 break; 1175 } 1176 if (i < nonce_max) { 1177 char ip6buf[INET6_ADDRSTRLEN]; 1178 1179 *found_nonce = true; 1180 log(LOG_DEBUG, 1181 "%s: detected a looped back NS message for %s\n", 1182 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???", 1183 IN6_PRINT(ip6buf, myaddr6)); 1184 dp->dad_ns_lcount++; 1185 continue; 1186 } 1187 1188 break; 1189 } 1190 return dp; 1191 } 1192 1193 static bool 1194 nd6_dad_ownnonce(struct ifaddr *ifa, struct nd_opt_nonce *nonce) 1195 { 1196 bool found_nonce = true; 1197 1198 mutex_enter(&nd6_dad_lock); 1199 nd6_dad_find(ifa, nonce, &found_nonce); 1200 mutex_exit(&nd6_dad_lock); 1201 1202 return found_nonce; 1203 } 1204 1205 static void 1206 nd6_dad_starttimer(struct dadq *dp, int ticks) 1207 { 1208 1209 callout_reset(&dp->dad_timer_ch, ticks, 1210 (void (*)(void *))nd6_dad_timer, dp); 1211 } 1212 1213 static void 1214 nd6_dad_stoptimer(struct dadq *dp) 1215 { 1216 1217 KASSERT(mutex_owned(&nd6_dad_lock)); 1218 1219 TAILQ_REMOVE(&dadq, dp, dad_list); 1220 /* Tell the timer that dp is being destroyed. */ 1221 dp->dad_ifa = NULL; 1222 callout_halt(&dp->dad_timer_ch, &nd6_dad_lock); 1223 } 1224 1225 static void 1226 nd6_dad_destroytimer(struct dadq *dp) 1227 { 1228 1229 KASSERT(dp->dad_ifa == NULL); 1230 callout_destroy(&dp->dad_timer_ch); 1231 kmem_intr_free(dp, sizeof(*dp)); 1232 } 1233 1234 /* 1235 * Start Duplicate Address Detection (DAD) for specified interface address. 1236 * 1237 * Note that callout is used when xtick > 0 and not when xtick == 0. 1238 * 1239 * xtick: minimum delay ticks for IFF_UP event 1240 */ 1241 void 1242 nd6_dad_start(struct ifaddr *ifa, int xtick) 1243 { 1244 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa; 1245 struct dadq *dp; 1246 char ip6buf[INET6_ADDRSTRLEN]; 1247 1248 /* 1249 * If we don't need DAD, don't do it. 1250 * There are several cases: 1251 * - DAD is disabled 1252 * - the interface address is anycast 1253 */ 1254 if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) { 1255 log(LOG_DEBUG, 1256 "nd6_dad_start: called with non-tentative address " 1257 "%s(%s)\n", 1258 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), 1259 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???"); 1260 return; 1261 } 1262 if (ia->ia6_flags & IN6_IFF_ANYCAST || !ip6_dad_enabled()) { 1263 ia->ia6_flags &= ~IN6_IFF_TENTATIVE; 1264 rt_addrmsg(RTM_NEWADDR, ifa); 1265 return; 1266 } 1267 KASSERT(ifa->ifa_ifp != NULL); 1268 if (!(ifa->ifa_ifp->if_flags & IFF_UP)) 1269 return; 1270 1271 dp = kmem_intr_alloc(sizeof(*dp), KM_NOSLEEP); 1272 1273 mutex_enter(&nd6_dad_lock); 1274 if (nd6_dad_find(ifa, NULL, NULL) != NULL) { 1275 mutex_exit(&nd6_dad_lock); 1276 /* DAD already in progress */ 1277 if (dp != NULL) 1278 kmem_intr_free(dp, sizeof(*dp)); 1279 return; 1280 } 1281 1282 if (dp == NULL) { 1283 mutex_exit(&nd6_dad_lock); 1284 log(LOG_ERR, "nd6_dad_start: memory allocation failed for " 1285 "%s(%s)\n", 1286 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), 1287 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???"); 1288 return; 1289 } 1290 1291 /* 1292 * Send NS packet for DAD, ip6_dad_count times. 1293 * Note that we must delay the first transmission, if this is the 1294 * first packet to be sent from the interface after interface 1295 * (re)initialization. 1296 */ 1297 callout_init(&dp->dad_timer_ch, CALLOUT_MPSAFE); 1298 dp->dad_ifa = ifa; 1299 ifaref(ifa); /* just for safety */ 1300 dp->dad_count = ip6_dad_count; 1301 dp->dad_ns_ocount = dp->dad_ns_tcount = 0; 1302 dp->dad_ns_lcount = 0; 1303 TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list); 1304 1305 nd6log(LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp), 1306 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr)); 1307 1308 if (xtick == 0) { 1309 nd6_dad_ns_output(dp, ifa); 1310 nd6_dad_starttimer(dp, 1311 (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000); 1312 } else 1313 nd6_dad_starttimer(dp, xtick); 1314 mutex_exit(&nd6_dad_lock); 1315 } 1316 1317 /* 1318 * terminate DAD unconditionally. used for address removals. 1319 */ 1320 void 1321 nd6_dad_stop(struct ifaddr *ifa) 1322 { 1323 struct dadq *dp; 1324 1325 mutex_enter(&nd6_dad_lock); 1326 dp = nd6_dad_find(ifa, NULL, NULL); 1327 if (dp == NULL) { 1328 mutex_exit(&nd6_dad_lock); 1329 /* DAD wasn't started yet */ 1330 return; 1331 } 1332 1333 /* Prevent the timer from running anymore. */ 1334 nd6_dad_stoptimer(dp); 1335 1336 mutex_exit(&nd6_dad_lock); 1337 1338 nd6_dad_destroytimer(dp); 1339 ifafree(ifa); 1340 } 1341 1342 static void 1343 nd6_dad_timer(struct dadq *dp) 1344 { 1345 struct ifaddr *ifa; 1346 struct in6_ifaddr *ia; 1347 char ip6buf[INET6_ADDRSTRLEN]; 1348 bool need_free = false; 1349 1350 KERNEL_LOCK_UNLESS_NET_MPSAFE(); 1351 mutex_enter(&nd6_dad_lock); 1352 1353 ifa = dp->dad_ifa; 1354 if (ifa == NULL) { 1355 /* dp is being destroyed by someone. Do nothing. */ 1356 goto done; 1357 } 1358 1359 ia = (struct in6_ifaddr *)ifa; 1360 if (ia->ia6_flags & IN6_IFF_DUPLICATED) { 1361 log(LOG_ERR, "nd6_dad_timer: called with duplicate address " 1362 "%s(%s)\n", 1363 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), 1364 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???"); 1365 goto done; 1366 } 1367 if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) { 1368 log(LOG_ERR, "nd6_dad_timer: called with non-tentative address " 1369 "%s(%s)\n", 1370 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), 1371 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???"); 1372 goto done; 1373 } 1374 1375 /* timeouted with IFF_{RUNNING,UP} check */ 1376 if (dp->dad_ns_tcount > dad_maxtry) { 1377 nd6log(LOG_INFO, "%s: could not run DAD, driver problem?\n", 1378 if_name(ifa->ifa_ifp)); 1379 1380 nd6_dad_stoptimer(dp); 1381 need_free = true; 1382 goto done; 1383 } 1384 1385 /* Need more checks? */ 1386 if (dp->dad_ns_ocount < dp->dad_count) { 1387 /* 1388 * We have more NS to go. Send NS packet for DAD. 1389 */ 1390 nd6_dad_ns_output(dp, ifa); 1391 nd6_dad_starttimer(dp, 1392 (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000); 1393 } else { 1394 /* 1395 * We are done with DAD. No NA came, no NS came. 1396 * No duplicate address found. 1397 */ 1398 ia->ia6_flags &= ~IN6_IFF_TENTATIVE; 1399 rt_addrmsg(RTM_NEWADDR, ifa); 1400 1401 nd6log(LOG_DEBUG, 1402 "%s: DAD complete for %s - no duplicates found\n", 1403 if_name(ifa->ifa_ifp), 1404 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr)); 1405 1406 nd6_dad_stoptimer(dp); 1407 need_free = true; 1408 } 1409 done: 1410 mutex_exit(&nd6_dad_lock); 1411 1412 if (need_free) { 1413 nd6_dad_destroytimer(dp); 1414 KASSERT(ifa != NULL); 1415 ifafree(ifa); 1416 } 1417 1418 KERNEL_UNLOCK_UNLESS_NET_MPSAFE(); 1419 } 1420 1421 static void 1422 nd6_dad_duplicated(struct ifaddr *ifa, struct dadq *dp, 1423 const struct sockaddr_dl *from) 1424 { 1425 struct in6_ifaddr *ia; 1426 struct ifnet *ifp; 1427 char ip6buf[INET6_ADDRSTRLEN], llabuf[LLA_ADDRSTRLEN], *llastr; 1428 1429 KASSERT(mutex_owned(&nd6_dad_lock)); 1430 KASSERT(ifa != NULL); 1431 1432 ifp = ifa->ifa_ifp; 1433 ia = (struct in6_ifaddr *)ifa; 1434 1435 ia->ia6_flags &= ~IN6_IFF_TENTATIVE; 1436 ia->ia6_flags |= IN6_IFF_DUPLICATED; 1437 1438 if (__predict_false(from == NULL)) 1439 llastr = NULL; 1440 else 1441 llastr = lla_snprintf(llabuf, sizeof(llabuf), 1442 CLLADDR(from), from->sdl_alen); 1443 1444 log(LOG_ERR, "%s: DAD duplicate address %s from %s\n", 1445 if_name(ifp), IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), llastr); 1446 1447 /* Inform the routing socket that DAD has completed */ 1448 rt_addrmsg_src(RTM_NEWADDR, ifa, (const struct sockaddr *)from); 1449 1450 /* 1451 * If the address is a link-local address formed from an interface 1452 * identifier based on the hardware address which is supposed to be 1453 * uniquely assigned (e.g., EUI-64 for an Ethernet interface), IP 1454 * operation on the interface SHOULD be disabled. 1455 * [rfc2462bis-03 Section 5.4.5] 1456 */ 1457 if (IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) { 1458 struct in6_addr in6; 1459 1460 /* 1461 * To avoid over-reaction, we only apply this logic when we are 1462 * very sure that hardware addresses are supposed to be unique. 1463 */ 1464 switch (ifp->if_type) { 1465 case IFT_ETHER: 1466 case IFT_FDDI: 1467 case IFT_ATM: 1468 case IFT_IEEE1394: 1469 case IFT_IEEE80211: 1470 in6 = ia->ia_addr.sin6_addr; 1471 if (in6_get_hw_ifid(ifp, &in6) == 0 && 1472 IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr, &in6)) { 1473 ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED; 1474 log(LOG_ERR, "%s: possible hardware address " 1475 "duplication detected, disable IPv6\n", 1476 if_name(ifp)); 1477 } 1478 break; 1479 } 1480 } 1481 } 1482 1483 static void 1484 nd6_dad_ns_output(struct dadq *dp, struct ifaddr *ifa) 1485 { 1486 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa; 1487 struct ifnet *ifp = ifa->ifa_ifp; 1488 uint8_t *nonce; 1489 1490 dp->dad_ns_tcount++; 1491 if ((ifp->if_flags & IFF_UP) == 0) { 1492 #if 0 1493 printf("%s: interface down?\n", if_name(ifp)); 1494 #endif 1495 return; 1496 } 1497 if ((ifp->if_flags & IFF_RUNNING) == 0) { 1498 #if 0 1499 printf("%s: interface not running?\n", if_name(ifp)); 1500 #endif 1501 return; 1502 } 1503 1504 dp->dad_ns_tcount = 0; 1505 nonce = dp->dad_nonce[dp->dad_ns_ocount % ND_OPT_NONCE_STORE]; 1506 cprng_fast(nonce, ND_OPT_NONCE_LEN); 1507 dp->dad_ns_ocount++; 1508 1509 nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, nonce); 1510 } 1511 1512 static void 1513 nd6_dad_input(struct ifaddr *ifa, struct nd_opt_nonce *nonce, 1514 const struct sockaddr_dl *from) 1515 { 1516 struct dadq *dp; 1517 bool found_nonce = false; 1518 1519 KASSERT(ifa != NULL); 1520 1521 mutex_enter(&nd6_dad_lock); 1522 dp = nd6_dad_find(ifa, nonce, &found_nonce); 1523 if (!found_nonce) { 1524 nd6_dad_duplicated(ifa, dp, from); 1525 if (dp != NULL) 1526 nd6_dad_stoptimer(dp); 1527 } 1528 mutex_exit(&nd6_dad_lock); 1529 if (dp != NULL) { 1530 nd6_dad_destroytimer(dp); 1531 ifafree(ifa); 1532 } 1533 } 1534
Indexes created Mon Sep 29 21:09:56 GMT 2025