nd6_nbr.c revision 1.153
1 /* $NetBSD: nd6_nbr.c,v 1.153 2018/03/19 03:14:08 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 1.153 2018/03/19 03:14:08 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 #include <net/net_osdep.h> 79 80 struct dadq; 81 static struct dadq *nd6_dad_find(struct ifaddr *, struct nd_opt_nonce *); 82 static void nd6_dad_starttimer(struct dadq *, int); 83 static void nd6_dad_destroytimer(struct dadq *); 84 static void nd6_dad_timer(struct dadq *); 85 static void nd6_dad_ns_output(struct dadq *, struct ifaddr *); 86 static void nd6_dad_ns_input(struct ifaddr *, struct nd_opt_nonce *); 87 static void nd6_dad_na_input(struct ifaddr *); 88 static void nd6_dad_duplicated(struct dadq *); 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 } 168 169 170 if (IN6_IS_ADDR_MULTICAST(&taddr6)) { 171 nd6log(LOG_INFO, "bad NS target (multicast)\n"); 172 goto bad; 173 } 174 175 icmp6len -= sizeof(*nd_ns); 176 nd6_option_init(nd_ns + 1, icmp6len, &ndopts); 177 if (nd6_options(&ndopts) < 0) { 178 nd6log(LOG_INFO, "invalid ND option, ignored\n"); 179 /* nd6_options have incremented stats */ 180 goto freeit; 181 } 182 183 if (ndopts.nd_opts_src_lladdr) { 184 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1); 185 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3; 186 } 187 188 if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) { 189 nd6log(LOG_INFO, 190 "bad DAD packet (link-layer address option)\n"); 191 goto bad; 192 } 193 194 /* 195 * Attaching target link-layer address to the NA? 196 * (RFC 2461 7.2.4) 197 * 198 * NS IP dst is multicast MUST add 199 * Otherwise MAY be omitted 200 * 201 * In this implementation, we omit the target link-layer address 202 * in the "MAY" case. 203 */ 204 #if 0 /* too much! */ 205 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6); 206 if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST)) 207 tlladdr = 0; 208 else 209 #endif 210 if (!IN6_IS_ADDR_MULTICAST(&daddr6)) 211 tlladdr = 0; 212 else 213 tlladdr = 1; 214 215 /* 216 * Target address (taddr6) must be either: 217 * (1) Valid unicast/anycast address for my receiving interface, 218 * (2) Unicast address for which I'm offering proxy service, or 219 * (3) "tentative" address on which DAD is being performed. 220 */ 221 /* (1) and (3) check. */ 222 #if NCARP > 0 223 if (ifp->if_carp && ifp->if_type != IFT_CARP) { 224 int s = pserialize_read_enter(); 225 ifa = carp_iamatch6(ifp->if_carp, &taddr6); 226 if (ifa != NULL) 227 ifa_acquire(ifa, &psref_ia); 228 pserialize_read_exit(s); 229 } else 230 ifa = NULL; 231 if (!ifa) 232 ifa = (struct ifaddr *)in6ifa_ifpwithaddr_psref(ifp, &taddr6, 233 &psref_ia); 234 #else 235 ifa = (struct ifaddr *)in6ifa_ifpwithaddr_psref(ifp, &taddr6, 236 &psref_ia); 237 #endif 238 239 /* (2) check. */ 240 if (ifa == NULL) { 241 struct rtentry *rt; 242 struct sockaddr_in6 tsin6; 243 244 sockaddr_in6_init(&tsin6, &taddr6, 0, 0, 0); 245 246 rt = rtalloc1(sin6tosa(&tsin6), 0); 247 if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 && 248 rt->rt_gateway->sa_family == AF_LINK) { 249 /* 250 * proxy NDP for single entry 251 */ 252 ifa = (struct ifaddr *)in6ifa_ifpforlinklocal_psref(ifp, 253 IN6_IFF_NOTREADY|IN6_IFF_ANYCAST, &psref_ia); 254 if (ifa) { 255 proxy = 1; 256 proxydl = satocsdl(rt->rt_gateway); 257 router = 0; /* XXX */ 258 } 259 } 260 if (rt) 261 rt_unref(rt); 262 } 263 if (ifa == NULL) { 264 /* 265 * We've got an NS packet, and we don't have that address 266 * assigned for us. We MUST silently ignore it. 267 * See RFC2461 7.2.3. 268 */ 269 goto freeit; 270 } 271 myaddr6 = *IFA_IN6(ifa); 272 anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST; 273 tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE; 274 if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED) 275 goto freeit; 276 277 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) { 278 nd6log(LOG_INFO, "lladdrlen mismatch for %s " 279 "(if %d, NS packet %d)\n", 280 IN6_PRINT(ip6buf, &taddr6), 281 ifp->if_addrlen, lladdrlen - 2); 282 goto bad; 283 } 284 285 if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) { 286 nd6log(LOG_INFO, "duplicate IP6 address %s\n", 287 IN6_PRINT(ip6buf, &saddr6)); 288 goto freeit; 289 } 290 291 /* 292 * We have neighbor solicitation packet, with target address equals to 293 * one of my tentative address. 294 * 295 * src addr how to process? 296 * --- --- 297 * multicast of course, invalid (rejected in ip6_input) 298 * unicast somebody is doing address resolution -> ignore 299 * unspec dup address detection 300 * 301 * The processing is defined in RFC 2462. 302 */ 303 if (tentative) { 304 /* 305 * If source address is unspecified address, it is for 306 * duplicate address detection. 307 * 308 * If not, the packet is for addess resolution; 309 * silently ignore it. 310 */ 311 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) 312 nd6_dad_ns_input(ifa, ndopts.nd_opts_nonce); 313 ifa_release(ifa, &psref_ia); 314 ifa = NULL; 315 316 goto freeit; 317 } 318 ifa_release(ifa, &psref_ia); 319 ifa = NULL; 320 321 /* 322 * If the source address is unspecified address, entries must not 323 * be created or updated. 324 * It looks that sender is performing DAD. Output NA toward 325 * all-node multicast address, to tell the sender that I'm using 326 * the address. 327 * S bit ("solicited") must be zero. 328 */ 329 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) { 330 struct in6_addr in6_all; 331 332 in6_all = in6addr_linklocal_allnodes; 333 if (in6_setscope(&in6_all, ifp, NULL) != 0) 334 goto bad; 335 nd6_na_output(ifp, &in6_all, &taddr6, 336 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) | 337 (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0), 338 tlladdr, (const struct sockaddr *)proxydl); 339 goto freeit; 340 } 341 342 nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0); 343 344 nd6_na_output(ifp, &saddr6, &taddr6, 345 ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) | 346 (router ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED, 347 tlladdr, (const struct sockaddr *)proxydl); 348 freeit: 349 ifa_release(ifa, &psref_ia); 350 m_put_rcvif_psref(ifp, &psref); 351 m_freem(m); 352 return; 353 354 bad: 355 nd6log(LOG_ERR, "src=%s\n", IN6_PRINT(ip6buf, &saddr6)); 356 nd6log(LOG_ERR, "dst=%s\n", IN6_PRINT(ip6buf, &daddr6)); 357 nd6log(LOG_ERR, "tgt=%s\n", IN6_PRINT(ip6buf, &taddr6)); 358 ICMP6_STATINC(ICMP6_STAT_BADNS); 359 ifa_release(ifa, &psref_ia); 360 m_put_rcvif_psref(ifp, &psref); 361 m_freem(m); 362 } 363 364 /* 365 * Output a Neighbor Solicitation Message. Caller specifies: 366 * - ICMP6 header source IP6 address 367 * - ND6 header target IP6 address 368 * - ND6 header source datalink address 369 * 370 * Based on RFC 2461 371 * Based on RFC 2462 (duplicate address detection) 372 */ 373 void 374 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *daddr6, 375 const struct in6_addr *taddr6, 376 struct in6_addr *hsrc, 377 uint8_t *nonce /* duplicate address detection */) 378 { 379 struct mbuf *m; 380 struct ip6_hdr *ip6; 381 struct nd_neighbor_solicit *nd_ns; 382 struct in6_addr *src, src_in; 383 struct ip6_moptions im6o; 384 int icmp6len; 385 int maxlen; 386 const void *mac; 387 struct route ro; 388 389 if (IN6_IS_ADDR_MULTICAST(taddr6)) 390 return; 391 392 memset(&ro, 0, sizeof(ro)); 393 394 /* estimate the size of message */ 395 maxlen = sizeof(*ip6) + sizeof(*nd_ns); 396 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7; 397 KASSERTMSG(max_linkhdr + maxlen < MCLBYTES, 398 "max_linkhdr + maxlen >= MCLBYTES (%d + %d >= %d)", 399 max_linkhdr, maxlen, MCLBYTES); 400 401 MGETHDR(m, M_DONTWAIT, MT_DATA); 402 if (m && max_linkhdr + maxlen >= MHLEN) { 403 MCLGET(m, M_DONTWAIT); 404 if ((m->m_flags & M_EXT) == 0) { 405 m_free(m); 406 m = NULL; 407 } 408 } 409 if (m == NULL) 410 return; 411 m_reset_rcvif(m); 412 413 if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) { 414 m->m_flags |= M_MCAST; 415 im6o.im6o_multicast_if_index = if_get_index(ifp); 416 im6o.im6o_multicast_hlim = 255; 417 im6o.im6o_multicast_loop = 0; 418 } 419 420 icmp6len = sizeof(*nd_ns); 421 m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len; 422 m->m_data += max_linkhdr; /* or MH_ALIGN() equivalent? */ 423 424 /* fill neighbor solicitation packet */ 425 ip6 = mtod(m, struct ip6_hdr *); 426 ip6->ip6_flow = 0; 427 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 428 ip6->ip6_vfc |= IPV6_VERSION; 429 /* ip6->ip6_plen will be set later */ 430 ip6->ip6_nxt = IPPROTO_ICMPV6; 431 ip6->ip6_hlim = 255; 432 if (daddr6) 433 ip6->ip6_dst = *daddr6; 434 else { 435 ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL; 436 ip6->ip6_dst.s6_addr16[1] = 0; 437 ip6->ip6_dst.s6_addr32[1] = 0; 438 ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE; 439 ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3]; 440 ip6->ip6_dst.s6_addr8[12] = 0xff; 441 if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0) 442 goto bad; 443 } 444 if (nonce == NULL) { 445 int s; 446 /* 447 * RFC2461 7.2.2: 448 * "If the source address of the packet prompting the 449 * solicitation is the same as one of the addresses assigned 450 * to the outgoing interface, that address SHOULD be placed 451 * in the IP Source Address of the outgoing solicitation. 452 * Otherwise, any one of the addresses assigned to the 453 * interface should be used." 454 * 455 * We use the source address for the prompting packet 456 * (hsrc), if: 457 * - hsrc is given from the caller (by giving "ln"), and 458 * - hsrc belongs to the outgoing interface. 459 * Otherwise, we perform the source address selection as usual. 460 */ 461 s = pserialize_read_enter(); 462 if (hsrc && in6ifa_ifpwithaddr(ifp, hsrc)) { 463 pserialize_read_exit(s); 464 src = hsrc; 465 } else { 466 int error; 467 struct sockaddr_in6 dst_sa; 468 469 pserialize_read_exit(s); 470 471 sockaddr_in6_init(&dst_sa, &ip6->ip6_dst, 0, 0, 0); 472 473 error = in6_selectsrc(&dst_sa, NULL, 474 NULL, &ro, NULL, NULL, NULL, &src_in); 475 if (error != 0) { 476 char ip6buf[INET6_ADDRSTRLEN]; 477 nd6log(LOG_DEBUG, "source can't be " 478 "determined: dst=%s, error=%d\n", 479 IN6_PRINT(ip6buf, &dst_sa.sin6_addr), 480 error); 481 pserialize_read_exit(s); 482 goto bad; 483 } 484 src = &src_in; 485 } 486 } else { 487 /* 488 * Source address for DAD packet must always be IPv6 489 * unspecified address. (0::0) 490 * We actually don't have to 0-clear the address (we did it 491 * above), but we do so here explicitly to make the intention 492 * clearer. 493 */ 494 memset(&src_in, 0, sizeof(src_in)); 495 src = &src_in; 496 } 497 ip6->ip6_src = *src; 498 nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1); 499 nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT; 500 nd_ns->nd_ns_code = 0; 501 nd_ns->nd_ns_reserved = 0; 502 nd_ns->nd_ns_target = *taddr6; 503 in6_clearscope(&nd_ns->nd_ns_target); /* XXX */ 504 505 /* 506 * Add source link-layer address option. 507 * 508 * spec implementation 509 * --- --- 510 * DAD packet MUST NOT do not add the option 511 * there's no link layer address: 512 * impossible do not add the option 513 * there's link layer address: 514 * Multicast NS MUST add one add the option 515 * Unicast NS SHOULD add one add the option 516 */ 517 if (nonce == NULL && (mac = nd6_ifptomac(ifp))) { 518 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen; 519 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1); 520 /* 8 byte alignments... */ 521 optlen = (optlen + 7) & ~7; 522 523 m->m_pkthdr.len += optlen; 524 m->m_len += optlen; 525 icmp6len += optlen; 526 memset((void *)nd_opt, 0, optlen); 527 nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; 528 nd_opt->nd_opt_len = optlen >> 3; 529 memcpy((void *)(nd_opt + 1), mac, ifp->if_addrlen); 530 } 531 532 /* Add a nonce option (RFC 3971) to detect looped back NS messages. 533 * This behavior is documented in RFC 7527. */ 534 if (nonce != NULL) { 535 int optlen = sizeof(struct nd_opt_hdr) + ND_OPT_NONCE_LEN; 536 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1); 537 538 /* 8-byte alignment is required. */ 539 optlen = (optlen + 7) & ~7; 540 m->m_pkthdr.len += optlen; 541 m->m_len += optlen; 542 icmp6len += optlen; 543 memset(nd_opt, 0, optlen); 544 nd_opt->nd_opt_type = ND_OPT_NONCE; 545 nd_opt->nd_opt_len = optlen >> 3; 546 memcpy(nd_opt + 1, nonce, ND_OPT_NONCE_LEN); 547 } 548 549 ip6->ip6_plen = htons((u_int16_t)icmp6len); 550 nd_ns->nd_ns_cksum = 0; 551 nd_ns->nd_ns_cksum = 552 in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len); 553 554 ip6_output(m, NULL, &ro, nonce != NULL ? IPV6_UNSPECSRC : 0, 555 &im6o, NULL, NULL); 556 icmp6_ifstat_inc(ifp, ifs6_out_msg); 557 icmp6_ifstat_inc(ifp, ifs6_out_neighborsolicit); 558 ICMP6_STATINC(ICMP6_STAT_OUTHIST + ND_NEIGHBOR_SOLICIT); 559 560 rtcache_free(&ro); 561 return; 562 563 bad: 564 rtcache_free(&ro); 565 m_freem(m); 566 return; 567 } 568 569 /* 570 * Neighbor advertisement input handling. 571 * 572 * Based on RFC 2461 573 * Based on RFC 2462 (duplicate address detection) 574 * 575 * the following items are not implemented yet: 576 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD) 577 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD) 578 */ 579 void 580 nd6_na_input(struct mbuf *m, int off, int icmp6len) 581 { 582 struct ifnet *ifp; 583 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 584 struct nd_neighbor_advert *nd_na; 585 struct in6_addr saddr6 = ip6->ip6_src; 586 struct in6_addr daddr6 = ip6->ip6_dst; 587 struct in6_addr taddr6; 588 int flags; 589 int is_router; 590 int is_solicited; 591 int is_override; 592 char *lladdr = NULL; 593 int lladdrlen = 0; 594 struct ifaddr *ifa; 595 struct llentry *ln = NULL; 596 union nd_opts ndopts; 597 struct sockaddr_in6 ssin6; 598 int rt_announce; 599 bool checklink = false; 600 struct psref psref; 601 struct psref psref_ia; 602 char ip6buf[INET6_ADDRSTRLEN], ip6buf2[INET6_ADDRSTRLEN]; 603 604 ifp = m_get_rcvif_psref(m, &psref); 605 if (ifp == NULL) 606 goto freeit; 607 608 if (ip6->ip6_hlim != 255) { 609 nd6log(LOG_ERR, 610 "invalid hlim (%d) from %s to %s on %s\n", 611 ip6->ip6_hlim, IN6_PRINT(ip6buf, &ip6->ip6_src), 612 IN6_PRINT(ip6buf2, &ip6->ip6_dst), if_name(ifp)); 613 goto bad; 614 } 615 616 IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len); 617 if (nd_na == NULL) { 618 m_put_rcvif_psref(ifp, &psref); 619 ICMP6_STATINC(ICMP6_STAT_TOOSHORT); 620 return; 621 } 622 623 flags = nd_na->nd_na_flags_reserved; 624 is_router = ((flags & ND_NA_FLAG_ROUTER) != 0); 625 is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0); 626 is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0); 627 628 taddr6 = nd_na->nd_na_target; 629 if (in6_setscope(&taddr6, ifp, NULL)) { 630 goto bad; 631 } 632 633 if (IN6_IS_ADDR_MULTICAST(&taddr6)) { 634 nd6log(LOG_ERR, "invalid target address %s\n", 635 IN6_PRINT(ip6buf, &taddr6)); 636 goto bad; 637 } 638 if (is_solicited && IN6_IS_ADDR_MULTICAST(&daddr6)) { 639 nd6log(LOG_ERR, "a solicited adv is multicasted\n"); 640 goto bad; 641 } 642 643 icmp6len -= sizeof(*nd_na); 644 nd6_option_init(nd_na + 1, icmp6len, &ndopts); 645 if (nd6_options(&ndopts) < 0) { 646 nd6log(LOG_INFO, "invalid ND option, ignored\n"); 647 /* nd6_options have incremented stats */ 648 goto freeit; 649 } 650 651 if (ndopts.nd_opts_tgt_lladdr) { 652 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1); 653 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3; 654 } 655 656 ifa = (struct ifaddr *)in6ifa_ifpwithaddr_psref(ifp, &taddr6, &psref_ia); 657 658 /* 659 * Target address matches one of my interface address. 660 * 661 * If my address is tentative, this means that there's somebody 662 * already using the same address as mine. This indicates DAD failure. 663 * This is defined in RFC 2462. 664 * 665 * Otherwise, process as defined in RFC 2461. 666 */ 667 if (ifa 668 && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) { 669 nd6_dad_na_input(ifa); 670 ifa_release(ifa, &psref_ia); 671 ifa = NULL; 672 goto freeit; 673 } 674 675 /* Just for safety, maybe unnecessary. */ 676 if (ifa) { 677 log(LOG_ERR, 678 "nd6_na_input: duplicate IP6 address %s\n", 679 IN6_PRINT(ip6buf, &taddr6)); 680 ifa_release(ifa, &psref_ia); 681 ifa = NULL; 682 goto freeit; 683 } 684 685 /* 686 * Make sure the source address is from a neighbor's address. 687 */ 688 sockaddr_in6_init(&ssin6, &saddr6, 0, 0, 0); 689 if (nd6_is_addr_neighbor(&ssin6, ifp) == 0) { 690 nd6log(LOG_INFO, "ND packet from non-neighbor %s on %s\n", 691 IN6_PRINT(ip6buf, &saddr6), if_name(ifp)); 692 goto bad; 693 } 694 695 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) { 696 nd6log(LOG_INFO, "lladdrlen mismatch for %s " 697 "(if %d, NA packet %d)\n", IN6_PRINT(ip6buf, &taddr6), 698 ifp->if_addrlen, lladdrlen - 2); 699 goto bad; 700 } 701 702 /* 703 * If no neighbor cache entry is found, NA SHOULD silently be 704 * discarded. 705 */ 706 ln = nd6_lookup(&taddr6, ifp, true); 707 if (ln == NULL) 708 goto freeit; 709 710 rt_announce = 0; 711 if (ln->ln_state == ND6_LLINFO_INCOMPLETE) { 712 /* 713 * If the link-layer has address, and no lladdr option came, 714 * discard the packet. 715 */ 716 if (ifp->if_addrlen && !lladdr) 717 goto freeit; 718 719 /* 720 * Record link-layer address, and update the state. 721 */ 722 memcpy(&ln->ll_addr, lladdr, ifp->if_addrlen); 723 ln->la_flags |= LLE_VALID; 724 rt_announce = 1; 725 if (is_solicited) { 726 ln->ln_state = ND6_LLINFO_REACHABLE; 727 ln->ln_byhint = 0; 728 if (!ND6_LLINFO_PERMANENT(ln)) { 729 nd6_llinfo_settimer(ln, 730 ND_IFINFO(ln->lle_tbl->llt_ifp)->reachable * hz); 731 } 732 } else { 733 ln->ln_state = ND6_LLINFO_STALE; 734 nd6_llinfo_settimer(ln, nd6_gctimer * hz); 735 } 736 if ((ln->ln_router = is_router) != 0) { 737 /* 738 * This means a router's state has changed from 739 * non-reachable to probably reachable, and might 740 * affect the status of associated prefixes.. 741 */ 742 checklink = true; 743 } 744 } else { 745 int llchange; 746 747 /* 748 * Check if the link-layer address has changed or not. 749 */ 750 if (lladdr == NULL) 751 llchange = 0; 752 else { 753 if (ln->la_flags & LLE_VALID) { 754 if (memcmp(lladdr, &ln->ll_addr, ifp->if_addrlen)) 755 llchange = rt_announce = 1; 756 else 757 llchange = 0; 758 } else 759 llchange = rt_announce = 1; 760 } 761 762 /* 763 * This is VERY complex. Look at it with care. 764 * 765 * override solicit lladdr llchange action 766 * (L: record lladdr) 767 * 768 * 0 0 n -- (2c) 769 * 0 0 y n (2b) L 770 * 0 0 y y (1) REACHABLE->STALE 771 * 0 1 n -- (2c) *->REACHABLE 772 * 0 1 y n (2b) L *->REACHABLE 773 * 0 1 y y (1) REACHABLE->STALE 774 * 1 0 n -- (2a) 775 * 1 0 y n (2a) L 776 * 1 0 y y (2a) L *->STALE 777 * 1 1 n -- (2a) *->REACHABLE 778 * 1 1 y n (2a) L *->REACHABLE 779 * 1 1 y y (2a) L *->REACHABLE 780 */ 781 if (!is_override && lladdr != NULL && llchange) { /* (1) */ 782 /* 783 * If state is REACHABLE, make it STALE. 784 * no other updates should be done. 785 */ 786 if (ln->ln_state == ND6_LLINFO_REACHABLE) { 787 ln->ln_state = ND6_LLINFO_STALE; 788 nd6_llinfo_settimer(ln, nd6_gctimer * hz); 789 } 790 goto freeit; 791 } else if (is_override /* (2a) */ 792 || (!is_override && lladdr != NULL && !llchange) /* (2b) */ 793 || lladdr == NULL) { /* (2c) */ 794 /* 795 * Update link-local address, if any. 796 */ 797 if (lladdr != NULL) { 798 memcpy(&ln->ll_addr, lladdr, ifp->if_addrlen); 799 ln->la_flags |= LLE_VALID; 800 } 801 802 /* 803 * If solicited, make the state REACHABLE. 804 * If not solicited and the link-layer address was 805 * changed, make it STALE. 806 */ 807 if (is_solicited) { 808 ln->ln_state = ND6_LLINFO_REACHABLE; 809 ln->ln_byhint = 0; 810 if (!ND6_LLINFO_PERMANENT(ln)) { 811 nd6_llinfo_settimer(ln, 812 ND_IFINFO(ifp)->reachable * hz); 813 } 814 } else { 815 if (lladdr && llchange) { 816 ln->ln_state = ND6_LLINFO_STALE; 817 nd6_llinfo_settimer(ln, 818 nd6_gctimer * hz); 819 } 820 } 821 } 822 823 if (ln->ln_router && !is_router) { 824 /* 825 * The peer dropped the router flag. 826 * Remove the sender from the Default Router List and 827 * update the Destination Cache entries. 828 */ 829 struct nd_defrouter *dr; 830 const struct in6_addr *in6; 831 832 in6 = &ln->r_l3addr.addr6; 833 834 ND6_WLOCK(); 835 dr = nd6_defrouter_lookup(in6, ln->lle_tbl->llt_ifp); 836 if (dr) 837 nd6_defrtrlist_del(dr, NULL); 838 else if (!ip6_forwarding) { 839 /* 840 * Even if the neighbor is not in the default 841 * router list, the neighbor may be used 842 * as a next hop for some destinations 843 * (e.g. redirect case). So we must 844 * call nd6_rt_flush explicitly. 845 */ 846 nd6_rt_flush(&ip6->ip6_src, ln->lle_tbl->llt_ifp); 847 } 848 ND6_UNLOCK(); 849 } 850 ln->ln_router = is_router; 851 } 852 /* 853 * XXX: does this matter? 854 * rt->rt_flags &= ~RTF_REJECT; 855 */ 856 ln->ln_asked = 0; 857 nd6_llinfo_release_pkts(ln, ifp); 858 /* FIXME */ 859 #if 0 860 if (rt_announce) /* tell user process about any new lladdr */ 861 rt_newmsg(RTM_CHANGE, rt); 862 #endif 863 864 freeit: 865 if (ln != NULL) 866 LLE_WUNLOCK(ln); 867 868 if (checklink) { 869 ND6_WLOCK(); 870 nd6_pfxlist_onlink_check(); 871 ND6_UNLOCK(); 872 } 873 874 m_put_rcvif_psref(ifp, &psref); 875 m_freem(m); 876 return; 877 878 bad: 879 if (ln != NULL) 880 LLE_WUNLOCK(ln); 881 882 ICMP6_STATINC(ICMP6_STAT_BADNA); 883 m_put_rcvif_psref(ifp, &psref); 884 m_freem(m); 885 } 886 887 /* 888 * Neighbor advertisement output handling. 889 * 890 * Based on RFC 2461 891 * 892 * the following items are not implemented yet: 893 * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD) 894 * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD) 895 */ 896 void 897 nd6_na_output( 898 struct ifnet *ifp, 899 const struct in6_addr *daddr6_0, 900 const struct in6_addr *taddr6, 901 u_long flags, 902 int tlladdr, /* 1 if include target link-layer address */ 903 const struct sockaddr *sdl0) /* sockaddr_dl (= proxy NA) or NULL */ 904 { 905 struct mbuf *m; 906 struct ip6_hdr *ip6; 907 struct nd_neighbor_advert *nd_na; 908 struct ip6_moptions im6o; 909 struct sockaddr *dst; 910 union { 911 struct sockaddr dst; 912 struct sockaddr_in6 dst6; 913 } u; 914 struct in6_addr daddr6; 915 int icmp6len, maxlen, error; 916 const void *mac; 917 struct route ro; 918 919 mac = NULL; 920 memset(&ro, 0, sizeof(ro)); 921 922 daddr6 = *daddr6_0; /* make a local copy for modification */ 923 924 /* estimate the size of message */ 925 maxlen = sizeof(*ip6) + sizeof(*nd_na); 926 maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7; 927 KASSERTMSG(max_linkhdr + maxlen < MCLBYTES, 928 "max_linkhdr + maxlen >= MCLBYTES (%d + %d >= %d)", 929 max_linkhdr, maxlen, MCLBYTES); 930 931 MGETHDR(m, M_DONTWAIT, MT_DATA); 932 if (m && max_linkhdr + maxlen >= MHLEN) { 933 MCLGET(m, M_DONTWAIT); 934 if ((m->m_flags & M_EXT) == 0) { 935 m_free(m); 936 m = NULL; 937 } 938 } 939 if (m == NULL) 940 return; 941 m_reset_rcvif(m); 942 943 if (IN6_IS_ADDR_MULTICAST(&daddr6)) { 944 m->m_flags |= M_MCAST; 945 im6o.im6o_multicast_if_index = if_get_index(ifp); 946 im6o.im6o_multicast_hlim = 255; 947 im6o.im6o_multicast_loop = 0; 948 } 949 950 icmp6len = sizeof(*nd_na); 951 m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len; 952 m->m_data += max_linkhdr; /* or MH_ALIGN() equivalent? */ 953 954 /* fill neighbor advertisement packet */ 955 ip6 = mtod(m, struct ip6_hdr *); 956 ip6->ip6_flow = 0; 957 ip6->ip6_vfc &= ~IPV6_VERSION_MASK; 958 ip6->ip6_vfc |= IPV6_VERSION; 959 ip6->ip6_nxt = IPPROTO_ICMPV6; 960 ip6->ip6_hlim = 255; 961 if (IN6_IS_ADDR_UNSPECIFIED(&daddr6)) { 962 /* reply to DAD */ 963 daddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL; 964 daddr6.s6_addr16[1] = 0; 965 daddr6.s6_addr32[1] = 0; 966 daddr6.s6_addr32[2] = 0; 967 daddr6.s6_addr32[3] = IPV6_ADDR_INT32_ONE; 968 if (in6_setscope(&daddr6, ifp, NULL)) 969 goto bad; 970 971 flags &= ~ND_NA_FLAG_SOLICITED; 972 } 973 ip6->ip6_dst = daddr6; 974 sockaddr_in6_init(&u.dst6, &daddr6, 0, 0, 0); 975 dst = &u.dst; 976 if (rtcache_setdst(&ro, dst) != 0) 977 goto bad; 978 979 /* 980 * Select a source whose scope is the same as that of the dest. 981 */ 982 error = in6_selectsrc(satosin6(dst), NULL, NULL, &ro, NULL, NULL, NULL, 983 &ip6->ip6_src); 984 if (error != 0) { 985 char ip6buf[INET6_ADDRSTRLEN]; 986 nd6log(LOG_DEBUG, "source can't be " 987 "determined: dst=%s, error=%d\n", 988 IN6_PRINT(ip6buf, &satocsin6(dst)->sin6_addr), error); 989 goto bad; 990 } 991 nd_na = (struct nd_neighbor_advert *)(ip6 + 1); 992 nd_na->nd_na_type = ND_NEIGHBOR_ADVERT; 993 nd_na->nd_na_code = 0; 994 nd_na->nd_na_target = *taddr6; 995 in6_clearscope(&nd_na->nd_na_target); /* XXX */ 996 997 /* 998 * "tlladdr" indicates NS's condition for adding tlladdr or not. 999 * see nd6_ns_input() for details. 1000 * Basically, if NS packet is sent to unicast/anycast addr, 1001 * target lladdr option SHOULD NOT be included. 1002 */ 1003 if (tlladdr) { 1004 /* 1005 * sdl0 != NULL indicates proxy NA. If we do proxy, use 1006 * lladdr in sdl0. If we are not proxying (sending NA for 1007 * my address) use lladdr configured for the interface. 1008 */ 1009 if (sdl0 == NULL) 1010 mac = nd6_ifptomac(ifp); 1011 else if (sdl0->sa_family == AF_LINK) { 1012 const struct sockaddr_dl *sdl; 1013 sdl = satocsdl(sdl0); 1014 if (sdl->sdl_alen == ifp->if_addrlen) 1015 mac = CLLADDR(sdl); 1016 } 1017 } 1018 if (tlladdr && mac) { 1019 int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen; 1020 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1); 1021 1022 /* roundup to 8 bytes alignment! */ 1023 optlen = (optlen + 7) & ~7; 1024 1025 m->m_pkthdr.len += optlen; 1026 m->m_len += optlen; 1027 icmp6len += optlen; 1028 memset((void *)nd_opt, 0, optlen); 1029 nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR; 1030 nd_opt->nd_opt_len = optlen >> 3; 1031 memcpy((void *)(nd_opt + 1), mac, ifp->if_addrlen); 1032 } else 1033 flags &= ~ND_NA_FLAG_OVERRIDE; 1034 1035 ip6->ip6_plen = htons((u_int16_t)icmp6len); 1036 nd_na->nd_na_flags_reserved = flags; 1037 nd_na->nd_na_cksum = 0; 1038 nd_na->nd_na_cksum = 1039 in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len); 1040 1041 ip6_output(m, NULL, NULL, 0, &im6o, NULL, NULL); 1042 1043 icmp6_ifstat_inc(ifp, ifs6_out_msg); 1044 icmp6_ifstat_inc(ifp, ifs6_out_neighboradvert); 1045 ICMP6_STATINC(ICMP6_STAT_OUTHIST + ND_NEIGHBOR_ADVERT); 1046 1047 rtcache_free(&ro); 1048 return; 1049 1050 bad: 1051 rtcache_free(&ro); 1052 m_freem(m); 1053 return; 1054 } 1055 1056 const void * 1057 nd6_ifptomac(const struct ifnet *ifp) 1058 { 1059 switch (ifp->if_type) { 1060 case IFT_ARCNET: 1061 case IFT_ETHER: 1062 case IFT_FDDI: 1063 case IFT_IEEE1394: 1064 case IFT_PROPVIRTUAL: 1065 case IFT_CARP: 1066 case IFT_L2VLAN: 1067 case IFT_IEEE80211: 1068 return CLLADDR(ifp->if_sadl); 1069 default: 1070 return NULL; 1071 } 1072 } 1073 1074 TAILQ_HEAD(dadq_head, dadq); 1075 struct dadq { 1076 TAILQ_ENTRY(dadq) dad_list; 1077 struct ifaddr *dad_ifa; 1078 int dad_count; /* max NS to send */ 1079 int dad_ns_tcount; /* # of trials to send NS */ 1080 int dad_ns_ocount; /* NS sent so far */ 1081 int dad_ns_icount; 1082 int dad_na_icount; 1083 int dad_ns_lcount; /* looped back NS */ 1084 struct callout dad_timer_ch; 1085 #define ND_OPT_NONCE_STORE 3 /* dad_count should not exceed this */ 1086 /* 1087 * The default ip6_dad_count is 1 as specified by RFC 4862 and 1088 * practically must users won't exceed this. 1089 * A storage of 3 is defaulted to here, in-case the administrator wants 1090 * to match the equivalent behaviour in our ARP implementation. 1091 * This constraint could be removed by sending the on wire nonce as 1092 * hmac(key, dad_ns_ocount), but that would increase the nonce size 1093 * sent on the wire. 1094 */ 1095 uint8_t dad_nonce[ND_OPT_NONCE_STORE][ND_OPT_NONCE_LEN]; 1096 }; 1097 1098 static struct dadq_head dadq; 1099 static int dad_init = 0; 1100 static kmutex_t nd6_dad_lock; 1101 1102 static struct dadq * 1103 nd6_dad_find(struct ifaddr *ifa, struct nd_opt_nonce *nonce) 1104 { 1105 struct dadq *dp; 1106 int i, nonce_max; 1107 1108 KASSERT(mutex_owned(&nd6_dad_lock)); 1109 1110 TAILQ_FOREACH(dp, &dadq, dad_list) { 1111 if (dp->dad_ifa != ifa) 1112 continue; 1113 1114 if (nonce == NULL || 1115 nonce->nd_opt_nonce_len != (ND_OPT_NONCE_LEN + 2) / 8) 1116 break; 1117 1118 nonce_max = MIN(dp->dad_ns_ocount, ND_OPT_NONCE_STORE); 1119 for (i = 0; i < nonce_max; i++) { 1120 if (memcmp(nonce->nd_opt_nonce, 1121 dp->dad_nonce[i], 1122 ND_OPT_NONCE_LEN) == 0) 1123 break; 1124 } 1125 if (i < nonce_max) { 1126 char ip6buf[INET6_ADDRSTRLEN]; 1127 1128 log(LOG_DEBUG, 1129 "%s: detected a looped back NS message for %s\n", 1130 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???", 1131 IN6_PRINT(ip6buf, IFA_IN6(ifa))); 1132 dp->dad_ns_lcount++; 1133 continue; 1134 } 1135 1136 break; 1137 } 1138 return dp; 1139 } 1140 1141 static void 1142 nd6_dad_starttimer(struct dadq *dp, int ticks) 1143 { 1144 1145 callout_reset(&dp->dad_timer_ch, ticks, 1146 (void (*)(void *))nd6_dad_timer, dp); 1147 } 1148 1149 static void 1150 nd6_dad_stoptimer(struct dadq *dp) 1151 { 1152 1153 KASSERT(mutex_owned(&nd6_dad_lock)); 1154 1155 TAILQ_REMOVE(&dadq, dp, dad_list); 1156 /* Tell the timer that dp is being destroyed. */ 1157 dp->dad_ifa = NULL; 1158 callout_halt(&dp->dad_timer_ch, &nd6_dad_lock); 1159 } 1160 1161 static void 1162 nd6_dad_destroytimer(struct dadq *dp) 1163 { 1164 1165 KASSERT(dp->dad_ifa == NULL); 1166 callout_destroy(&dp->dad_timer_ch); 1167 kmem_intr_free(dp, sizeof(*dp)); 1168 } 1169 1170 /* 1171 * Start Duplicate Address Detection (DAD) for specified interface address. 1172 * 1173 * Note that callout is used when xtick > 0 and not when xtick == 0. 1174 * 1175 * xtick: minimum delay ticks for IFF_UP event 1176 */ 1177 void 1178 nd6_dad_start(struct ifaddr *ifa, int xtick) 1179 { 1180 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa; 1181 struct dadq *dp; 1182 char ip6buf[INET6_ADDRSTRLEN]; 1183 1184 if (!dad_init) { 1185 TAILQ_INIT(&dadq); 1186 mutex_init(&nd6_dad_lock, MUTEX_DEFAULT, IPL_NONE); 1187 dad_init++; 1188 } 1189 1190 /* 1191 * If we don't need DAD, don't do it. 1192 * There are several cases: 1193 * - DAD is disabled (ip6_dad_count == 0) 1194 * - the interface address is anycast 1195 */ 1196 if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) { 1197 log(LOG_DEBUG, 1198 "nd6_dad_start: called with non-tentative address " 1199 "%s(%s)\n", 1200 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), 1201 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???"); 1202 return; 1203 } 1204 if (ia->ia6_flags & IN6_IFF_ANYCAST || !ip6_dad_count) { 1205 ia->ia6_flags &= ~IN6_IFF_TENTATIVE; 1206 rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL); 1207 return; 1208 } 1209 KASSERT(ifa->ifa_ifp != NULL); 1210 if (!(ifa->ifa_ifp->if_flags & IFF_UP)) 1211 return; 1212 1213 dp = kmem_intr_alloc(sizeof(*dp), KM_NOSLEEP); 1214 1215 mutex_enter(&nd6_dad_lock); 1216 if (nd6_dad_find(ifa, NULL) != NULL) { 1217 mutex_exit(&nd6_dad_lock); 1218 /* DAD already in progress */ 1219 if (dp != NULL) 1220 kmem_intr_free(dp, sizeof(*dp)); 1221 return; 1222 } 1223 1224 if (dp == NULL) { 1225 mutex_exit(&nd6_dad_lock); 1226 log(LOG_ERR, "nd6_dad_start: memory allocation failed for " 1227 "%s(%s)\n", 1228 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), 1229 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???"); 1230 return; 1231 } 1232 1233 /* 1234 * Send NS packet for DAD, ip6_dad_count times. 1235 * Note that we must delay the first transmission, if this is the 1236 * first packet to be sent from the interface after interface 1237 * (re)initialization. 1238 */ 1239 callout_init(&dp->dad_timer_ch, CALLOUT_MPSAFE); 1240 dp->dad_ifa = ifa; 1241 ifaref(ifa); /* just for safety */ 1242 dp->dad_count = ip6_dad_count; 1243 dp->dad_ns_icount = dp->dad_na_icount = 0; 1244 dp->dad_ns_ocount = dp->dad_ns_tcount = 0; 1245 dp->dad_ns_lcount = 0; 1246 TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list); 1247 1248 nd6log(LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp), 1249 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr)); 1250 1251 if (xtick == 0) { 1252 nd6_dad_ns_output(dp, ifa); 1253 nd6_dad_starttimer(dp, 1254 (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000); 1255 } else 1256 nd6_dad_starttimer(dp, xtick); 1257 mutex_exit(&nd6_dad_lock); 1258 } 1259 1260 /* 1261 * terminate DAD unconditionally. used for address removals. 1262 */ 1263 void 1264 nd6_dad_stop(struct ifaddr *ifa) 1265 { 1266 struct dadq *dp; 1267 1268 if (!dad_init) 1269 return; 1270 1271 mutex_enter(&nd6_dad_lock); 1272 dp = nd6_dad_find(ifa, NULL); 1273 if (dp == NULL) { 1274 mutex_exit(&nd6_dad_lock); 1275 /* DAD wasn't started yet */ 1276 return; 1277 } 1278 1279 /* Prevent the timer from running anymore. */ 1280 nd6_dad_stoptimer(dp); 1281 1282 mutex_exit(&nd6_dad_lock); 1283 1284 nd6_dad_destroytimer(dp); 1285 ifafree(ifa); 1286 } 1287 1288 static void 1289 nd6_dad_timer(struct dadq *dp) 1290 { 1291 struct ifaddr *ifa; 1292 struct in6_ifaddr *ia; 1293 int duplicate = 0; 1294 char ip6buf[INET6_ADDRSTRLEN]; 1295 bool need_free = false; 1296 1297 KERNEL_LOCK_UNLESS_NET_MPSAFE(); 1298 mutex_enter(&nd6_dad_lock); 1299 1300 ifa = dp->dad_ifa; 1301 if (ifa == NULL) { 1302 /* dp is being destroyed by someone. Do nothing. */ 1303 goto done; 1304 } 1305 1306 ia = (struct in6_ifaddr *)ifa; 1307 if (ia->ia6_flags & IN6_IFF_DUPLICATED) { 1308 log(LOG_ERR, "nd6_dad_timer: called with duplicate address " 1309 "%s(%s)\n", 1310 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), 1311 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???"); 1312 goto done; 1313 } 1314 if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) { 1315 log(LOG_ERR, "nd6_dad_timer: called with non-tentative address " 1316 "%s(%s)\n", 1317 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), 1318 ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???"); 1319 goto done; 1320 } 1321 1322 /* timeouted with IFF_{RUNNING,UP} check */ 1323 if (dp->dad_ns_tcount > dad_maxtry) { 1324 nd6log(LOG_INFO, "%s: could not run DAD, driver problem?\n", 1325 if_name(ifa->ifa_ifp)); 1326 1327 nd6_dad_stoptimer(dp); 1328 need_free = true; 1329 goto done; 1330 } 1331 1332 /* Need more checks? */ 1333 if (dp->dad_ns_ocount < dp->dad_count) { 1334 /* 1335 * We have more NS to go. Send NS packet for DAD. 1336 */ 1337 nd6_dad_ns_output(dp, ifa); 1338 nd6_dad_starttimer(dp, 1339 (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000); 1340 } else { 1341 /* 1342 * We have transmitted sufficient number of DAD packets. 1343 * See what we've got. 1344 */ 1345 if (dp->dad_na_icount) { 1346 /* 1347 * the check is in nd6_dad_na_input(), 1348 * but just in case 1349 */ 1350 duplicate++; 1351 } 1352 1353 if (dp->dad_ns_icount) { 1354 /* We've seen NS, means DAD has failed. */ 1355 duplicate++; 1356 } 1357 1358 if (duplicate) { 1359 nd6_dad_duplicated(dp); 1360 nd6_dad_stoptimer(dp); 1361 need_free = true; 1362 } else { 1363 /* 1364 * We are done with DAD. No NA came, no NS came. 1365 * No duplicate address found. 1366 */ 1367 ia->ia6_flags &= ~IN6_IFF_TENTATIVE; 1368 rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL); 1369 1370 nd6log(LOG_DEBUG, 1371 "%s: DAD complete for %s - no duplicates found\n", 1372 if_name(ifa->ifa_ifp), 1373 IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr)); 1374 1375 nd6_dad_stoptimer(dp); 1376 need_free = true; 1377 } 1378 } 1379 done: 1380 mutex_exit(&nd6_dad_lock); 1381 1382 if (need_free) { 1383 nd6_dad_destroytimer(dp); 1384 KASSERT(ifa != NULL); 1385 ifafree(ifa); 1386 } 1387 1388 KERNEL_UNLOCK_UNLESS_NET_MPSAFE(); 1389 } 1390 1391 static void 1392 nd6_dad_duplicated(struct dadq *dp) 1393 { 1394 struct ifaddr *ifa = dp->dad_ifa; 1395 struct in6_ifaddr *ia; 1396 struct ifnet *ifp; 1397 char ip6buf[INET6_ADDRSTRLEN]; 1398 1399 KASSERT(mutex_owned(&nd6_dad_lock)); 1400 KASSERT(ifa != NULL); 1401 1402 ifp = ifa->ifa_ifp; 1403 ia = (struct in6_ifaddr *)ifa; 1404 log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: " 1405 "NS in/out/loopback=%d/%d/%d, NA in=%d\n", 1406 if_name(ifp), IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), 1407 dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_ns_lcount, 1408 dp->dad_na_icount); 1409 1410 ia->ia6_flags &= ~IN6_IFF_TENTATIVE; 1411 ia->ia6_flags |= IN6_IFF_DUPLICATED; 1412 1413 log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n", 1414 if_name(ifp), IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr)); 1415 log(LOG_ERR, "%s: manual intervention required\n", 1416 if_name(ifp)); 1417 1418 /* Inform the routing socket that DAD has completed */ 1419 rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL); 1420 1421 /* 1422 * If the address is a link-local address formed from an interface 1423 * identifier based on the hardware address which is supposed to be 1424 * uniquely assigned (e.g., EUI-64 for an Ethernet interface), IP 1425 * operation on the interface SHOULD be disabled. 1426 * [rfc2462bis-03 Section 5.4.5] 1427 */ 1428 if (IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) { 1429 struct in6_addr in6; 1430 1431 /* 1432 * To avoid over-reaction, we only apply this logic when we are 1433 * very sure that hardware addresses are supposed to be unique. 1434 */ 1435 switch (ifp->if_type) { 1436 case IFT_ETHER: 1437 case IFT_FDDI: 1438 case IFT_ATM: 1439 case IFT_IEEE1394: 1440 case IFT_IEEE80211: 1441 in6 = ia->ia_addr.sin6_addr; 1442 if (in6_get_hw_ifid(ifp, &in6) == 0 && 1443 IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr, &in6)) { 1444 ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED; 1445 log(LOG_ERR, "%s: possible hardware address " 1446 "duplication detected, disable IPv6\n", 1447 if_name(ifp)); 1448 } 1449 break; 1450 } 1451 } 1452 } 1453 1454 static void 1455 nd6_dad_ns_output(struct dadq *dp, struct ifaddr *ifa) 1456 { 1457 struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa; 1458 struct ifnet *ifp = ifa->ifa_ifp; 1459 uint8_t *nonce; 1460 1461 dp->dad_ns_tcount++; 1462 if ((ifp->if_flags & IFF_UP) == 0) { 1463 #if 0 1464 printf("%s: interface down?\n", if_name(ifp)); 1465 #endif 1466 return; 1467 } 1468 if ((ifp->if_flags & IFF_RUNNING) == 0) { 1469 #if 0 1470 printf("%s: interface not running?\n", if_name(ifp)); 1471 #endif 1472 return; 1473 } 1474 1475 dp->dad_ns_tcount = 0; 1476 nonce = dp->dad_nonce[dp->dad_ns_ocount % ND_OPT_NONCE_STORE]; 1477 cprng_fast(nonce, ND_OPT_NONCE_LEN); 1478 dp->dad_ns_ocount++; 1479 1480 nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, nonce); 1481 } 1482 1483 static void 1484 nd6_dad_ns_input(struct ifaddr *ifa, struct nd_opt_nonce *nonce) 1485 { 1486 struct dadq *dp; 1487 int duplicate; 1488 1489 if (ifa == NULL) 1490 panic("ifa == NULL in nd6_dad_ns_input"); 1491 1492 duplicate = 0; 1493 1494 mutex_enter(&nd6_dad_lock); 1495 dp = nd6_dad_find(ifa, nonce); 1496 1497 /* 1498 * if I'm yet to start DAD, someone else started using this address 1499 * first. I have a duplicate and you win. 1500 */ 1501 if (dp == NULL || dp->dad_ns_ocount == 0) 1502 duplicate++; 1503 1504 /* XXX more checks for loopback situation - see nd6_dad_timer too */ 1505 1506 if (duplicate) { 1507 if (dp) { 1508 nd6_dad_duplicated(dp); 1509 nd6_dad_stoptimer(dp); 1510 } 1511 } else { 1512 /* 1513 * not sure if I got a duplicate. 1514 * increment ns count and see what happens. 1515 */ 1516 if (dp) 1517 dp->dad_ns_icount++; 1518 } 1519 mutex_exit(&nd6_dad_lock); 1520 1521 if (duplicate && dp) { 1522 nd6_dad_destroytimer(dp); 1523 ifafree(ifa); 1524 } 1525 } 1526 1527 static void 1528 nd6_dad_na_input(struct ifaddr *ifa) 1529 { 1530 struct dadq *dp; 1531 1532 KASSERT(ifa != NULL); 1533 1534 mutex_enter(&nd6_dad_lock); 1535 1536 dp = nd6_dad_find(ifa, NULL); 1537 if (dp == NULL) { 1538 mutex_exit(&nd6_dad_lock); 1539 return; 1540 } 1541 1542 dp->dad_na_icount++; 1543 1544 /* remove the address. */ 1545 nd6_dad_duplicated(dp); 1546 nd6_dad_stoptimer(dp); 1547 1548 mutex_exit(&nd6_dad_lock); 1549 1550 nd6_dad_destroytimer(dp); 1551 ifafree(ifa); 1552 } 1553
Indexes created Mon Sep 29 21:09:56 GMT 2025