in6_ifattach.c revision 1.100
1/* $OpenBSD: in6_ifattach.c,v 1.100 2016/06/30 08:19:03 mpi Exp $ */ 2/* $KAME: in6_ifattach.c,v 1.124 2001/07/18 08:32:51 jinmei Exp $ */ 3 4/* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33#include <sys/param.h> 34#include <sys/systm.h> 35#include <sys/socket.h> 36#include <sys/sockio.h> 37#include <sys/kernel.h> 38#include <sys/syslog.h> 39 40#include <crypto/sha2.h> 41 42#include <net/if.h> 43#include <net/if_var.h> 44#include <net/if_dl.h> 45#include <net/if_types.h> 46#include <net/route.h> 47 48#include <netinet/in.h> 49 50#include <netinet6/in6_var.h> 51#include <netinet/ip6.h> 52#include <netinet6/ip6_var.h> 53#include <netinet6/in6_ifattach.h> 54#include <netinet6/nd6.h> 55#ifdef MROUTING 56#include <netinet6/ip6_mroute.h> 57#endif 58 59int get_last_resort_ifid(struct ifnet *, struct in6_addr *); 60int get_hw_ifid(struct ifnet *, struct in6_addr *); 61int get_ifid(struct ifnet *, struct in6_addr *); 62int in6_ifattach_loopback(struct ifnet *); 63 64#define EUI64_GBIT 0x01 65#define EUI64_UBIT 0x02 66#define EUI64_TO_IFID(in6) do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0) 67#define EUI64_GROUP(in6) ((in6)->s6_addr[8] & EUI64_GBIT) 68#define EUI64_INDIVIDUAL(in6) (!EUI64_GROUP(in6)) 69#define EUI64_LOCAL(in6) ((in6)->s6_addr[8] & EUI64_UBIT) 70#define EUI64_UNIVERSAL(in6) (!EUI64_LOCAL(in6)) 71 72#define IFID_LOCAL(in6) (!EUI64_LOCAL(in6)) 73#define IFID_UNIVERSAL(in6) (!EUI64_UNIVERSAL(in6)) 74 75/* 76 * Generate a last-resort interface identifier, when the machine has no 77 * IEEE802/EUI64 address sources. 78 * The goal here is to get an interface identifier that is 79 * (1) random enough and (2) does not change across reboot. 80 * We currently use SHA512(hostname) for it. 81 * 82 * in6 - upper 64bits are preserved 83 */ 84int 85get_last_resort_ifid(struct ifnet *ifp, struct in6_addr *in6) 86{ 87 SHA2_CTX ctx; 88 u_int8_t digest[SHA512_DIGEST_LENGTH]; 89 90#if 0 91 /* we need at least several letters as seed for ifid */ 92 if (hostnamelen < 3) 93 return -1; 94#endif 95 96 /* generate 8 bytes of pseudo-random value. */ 97 SHA512Init(&ctx); 98 SHA512Update(&ctx, hostname, hostnamelen); 99 SHA512Final(digest, &ctx); 100 101 /* assumes sizeof(digest) > sizeof(ifid) */ 102 bcopy(digest, &in6->s6_addr[8], 8); 103 104 /* make sure to set "u" bit to local, and "g" bit to individual. */ 105 in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */ 106 in6->s6_addr[8] |= EUI64_UBIT; /* u bit to "local" */ 107 108 /* convert EUI64 into IPv6 interface identifier */ 109 EUI64_TO_IFID(in6); 110 111 return 0; 112} 113 114/* 115 * Generate a random interface identifier. 116 * 117 * in6 - upper 64bits are preserved 118 */ 119void 120in6_get_rand_ifid(struct ifnet *ifp, struct in6_addr *in6) 121{ 122 arc4random_buf(&in6->s6_addr32[2], 8); 123 124 /* make sure to set "u" bit to local, and "g" bit to individual. */ 125 in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */ 126 in6->s6_addr[8] |= EUI64_UBIT; /* u bit to "local" */ 127 128 /* convert EUI64 into IPv6 interface identifier */ 129 EUI64_TO_IFID(in6); 130} 131 132/* 133 * Get interface identifier for the specified interface. 134 * 135 * in6 - upper 64bits are preserved 136 */ 137int 138get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6) 139{ 140 struct sockaddr_dl *sdl; 141 char *addr; 142 size_t addrlen; 143 static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 }; 144 static u_int8_t allone[8] = 145 { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; 146 147 sdl = ifp->if_sadl; 148 if (sdl == NULL || sdl->sdl_alen == 0) 149 return -1; 150 151 addr = LLADDR(sdl); 152 addrlen = sdl->sdl_alen; 153 154 switch (ifp->if_type) { 155 case IFT_IEEE1394: 156 case IFT_IEEE80211: 157 /* IEEE1394 uses 16byte length address starting with EUI64 */ 158 if (addrlen > 8) 159 addrlen = 8; 160 break; 161 default: 162 break; 163 } 164 165 /* get EUI64 */ 166 switch (ifp->if_type) { 167 /* IEEE802/EUI64 cases - what others? */ 168 case IFT_ETHER: 169 case IFT_CARP: 170 case IFT_IEEE1394: 171 case IFT_IEEE80211: 172 /* look at IEEE802/EUI64 only */ 173 if (addrlen != 8 && addrlen != 6) 174 return -1; 175 176 /* 177 * check for invalid MAC address - on bsdi, we see it a lot 178 * since wildboar configures all-zero MAC on pccard before 179 * card insertion. 180 */ 181 if (bcmp(addr, allzero, addrlen) == 0) 182 return -1; 183 if (bcmp(addr, allone, addrlen) == 0) 184 return -1; 185 186 /* make EUI64 address */ 187 if (addrlen == 8) 188 bcopy(addr, &in6->s6_addr[8], 8); 189 else if (addrlen == 6) { 190 in6->s6_addr[8] = addr[0]; 191 in6->s6_addr[9] = addr[1]; 192 in6->s6_addr[10] = addr[2]; 193 in6->s6_addr[11] = 0xff; 194 in6->s6_addr[12] = 0xfe; 195 in6->s6_addr[13] = addr[3]; 196 in6->s6_addr[14] = addr[4]; 197 in6->s6_addr[15] = addr[5]; 198 } 199 break; 200 201 case IFT_GIF: 202 /* 203 * RFC2893 says: "SHOULD use IPv4 address as ifid source". 204 * however, IPv4 address is not very suitable as unique 205 * identifier source (can be renumbered). 206 * we don't do this. 207 */ 208 return -1; 209 210 default: 211 return -1; 212 } 213 214 /* sanity check: g bit must not indicate "group" */ 215 if (EUI64_GROUP(in6)) 216 return -1; 217 218 /* convert EUI64 into IPv6 interface identifier */ 219 EUI64_TO_IFID(in6); 220 221 /* 222 * sanity check: ifid must not be all zero, avoid conflict with 223 * subnet router anycast 224 */ 225 if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 && 226 bcmp(&in6->s6_addr[9], allzero, 7) == 0) { 227 return -1; 228 } 229 230 return 0; 231} 232 233/* 234 * Get interface identifier for the specified interface. If it is not 235 * available on ifp0, borrow interface identifier from other information 236 * sources. 237 */ 238int 239get_ifid(struct ifnet *ifp0, struct in6_addr *in6) 240{ 241 struct ifnet *ifp; 242 243 /* first, try to get it from the interface itself */ 244 if (get_hw_ifid(ifp0, in6) == 0) { 245 nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n", 246 ifp0->if_xname)); 247 goto success; 248 } 249 250 /* next, try to get it from some other hardware interface */ 251 TAILQ_FOREACH(ifp, &ifnet, if_list) { 252 if (ifp == ifp0) 253 continue; 254 if (get_hw_ifid(ifp, in6) != 0) 255 continue; 256 257 /* 258 * to borrow ifid from other interface, ifid needs to be 259 * globally unique 260 */ 261 if (IFID_UNIVERSAL(in6)) { 262 nd6log((LOG_DEBUG, 263 "%s: borrow interface identifier from %s\n", 264 ifp0->if_xname, ifp->if_xname)); 265 goto success; 266 } 267 } 268 269 /* last resort: get from random number source */ 270 if (get_last_resort_ifid(ifp, in6) == 0) { 271 nd6log((LOG_DEBUG, 272 "%s: interface identifier generated by random number\n", 273 ifp0->if_xname)); 274 goto success; 275 } 276 277 printf("%s: failed to get interface identifier\n", ifp0->if_xname); 278 return -1; 279 280success: 281 nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n", 282 ifp0->if_xname, in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10], 283 in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13], 284 in6->s6_addr[14], in6->s6_addr[15])); 285 return 0; 286} 287 288/* 289 * ifid - used as EUI64 if not NULL, overrides other EUI64 sources 290 */ 291 292int 293in6_ifattach_linklocal(struct ifnet *ifp, struct in6_addr *ifid) 294{ 295 struct in6_aliasreq ifra; 296 struct in6_ifaddr *ia6; 297 int s, error, flags; 298 299 /* 300 * configure link-local address. 301 */ 302 bzero(&ifra, sizeof(ifra)); 303 strncpy(ifra.ifra_name, ifp->if_xname, sizeof(ifra.ifra_name)); 304 ifra.ifra_addr.sin6_family = AF_INET6; 305 ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6); 306 ifra.ifra_addr.sin6_addr.s6_addr16[0] = htons(0xfe80); 307 ifra.ifra_addr.sin6_addr.s6_addr16[1] = htons(ifp->if_index); 308 ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0; 309 if ((ifp->if_flags & IFF_LOOPBACK) != 0) { 310 ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0; 311 ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1); 312 } else if (ifid) { 313 ifra.ifra_addr.sin6_addr = *ifid; 314 ifra.ifra_addr.sin6_addr.s6_addr16[0] = htons(0xfe80); 315 ifra.ifra_addr.sin6_addr.s6_addr16[1] = htons(ifp->if_index); 316 ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0; 317 ifra.ifra_addr.sin6_addr.s6_addr[8] &= ~EUI64_GBIT; 318 ifra.ifra_addr.sin6_addr.s6_addr[8] |= EUI64_UBIT; 319 } else { 320 if (get_ifid(ifp, &ifra.ifra_addr.sin6_addr) != 0) { 321 nd6log((LOG_ERR, 322 "%s: no ifid available\n", ifp->if_xname)); 323 return (-1); 324 } 325 } 326 327 ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6); 328 ifra.ifra_prefixmask.sin6_family = AF_INET6; 329 ifra.ifra_prefixmask.sin6_addr = in6mask64; 330 /* link-local addresses should NEVER expire. */ 331 ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME; 332 ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME; 333 334 /* 335 * XXX: Some P2P interfaces seem not to send packets just after 336 * becoming up, so we skip p2p interfaces for safety. 337 */ 338 if (in6if_do_dad(ifp) && ((ifp->if_flags & IFF_POINTOPOINT) == 0)) 339 ifra.ifra_flags |= IN6_IFF_TENTATIVE; 340 341 s = splsoftnet(); 342 error = in6_update_ifa(ifp, &ifra, in6ifa_ifpforlinklocal(ifp, 0)); 343 splx(s); 344 if (error != 0) 345 return (error); 346 347 ia6 = in6ifa_ifpforlinklocal(ifp, 0); 348 349 /* Perform DAD, if needed. */ 350 if (ia6->ia6_flags & IN6_IFF_TENTATIVE) 351 nd6_dad_start(&ia6->ia_ifa); 352 353 if (ifp->if_flags & IFF_LOOPBACK) { 354 dohooks(ifp->if_addrhooks, 0); 355 return (0); /* No need to install a connected route. */ 356 } 357 358 flags = RTF_CONNECTED; 359 if ((ifp->if_flags & IFF_POINTOPOINT) == 0) 360 flags |= RTF_CLONING; 361 362 s = splsoftnet(); 363 error = rt_ifa_add(&ia6->ia_ifa, flags, ia6->ia_ifa.ifa_addr); 364 if (error) { 365 in6_purgeaddr(&ia6->ia_ifa); 366 splx(s); 367 return (error); 368 } 369 dohooks(ifp->if_addrhooks, 0); 370 splx(s); 371 372 return (0); 373} 374 375int 376in6_ifattach_loopback(struct ifnet *ifp) 377{ 378 struct in6_aliasreq ifra; 379 380 KASSERT(ifp->if_flags & IFF_LOOPBACK); 381 382 bzero(&ifra, sizeof(ifra)); 383 strncpy(ifra.ifra_name, ifp->if_xname, sizeof(ifra.ifra_name)); 384 ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6); 385 ifra.ifra_prefixmask.sin6_family = AF_INET6; 386 ifra.ifra_prefixmask.sin6_addr = in6mask128; 387 388 /* 389 * Always initialize ia_dstaddr (= broadcast address) to loopback 390 * address. Follows IPv4 practice - see in_ifinit(). 391 */ 392 ifra.ifra_dstaddr.sin6_len = sizeof(struct sockaddr_in6); 393 ifra.ifra_dstaddr.sin6_family = AF_INET6; 394 ifra.ifra_dstaddr.sin6_addr = in6addr_loopback; 395 396 ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6); 397 ifra.ifra_addr.sin6_family = AF_INET6; 398 ifra.ifra_addr.sin6_addr = in6addr_loopback; 399 400 /* the loopback address should NEVER expire. */ 401 ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME; 402 ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME; 403 404 /* 405 * We are sure that this is a newly assigned address, so we can set 406 * NULL to the 3rd arg. 407 */ 408 return (in6_update_ifa(ifp, &ifra, NULL)); 409} 410 411/* 412 * compute NI group address, based on the current hostname setting. 413 * see draft-ietf-ipngwg-icmp-name-lookup-* (04 and later). 414 * 415 * when ifp == NULL, the caller is responsible for filling scopeid. 416 */ 417int 418in6_nigroup(struct ifnet *ifp, const char *name, int namelen, 419 struct sockaddr_in6 *sa6) 420{ 421 const char *p; 422 u_int8_t *q; 423 SHA2_CTX ctx; 424 u_int8_t digest[SHA512_DIGEST_LENGTH]; 425 u_int8_t l; 426 u_int8_t n[64]; /* a single label must not exceed 63 chars */ 427 428 if (!namelen || !name) 429 return -1; 430 431 p = name; 432 while (p && *p && *p != '.' && p - name < namelen) 433 p++; 434 if (p - name > sizeof(n) - 1) 435 return -1; /* label too long */ 436 l = p - name; 437 strncpy((char *)n, name, l); 438 n[(int)l] = '\0'; 439 for (q = n; *q; q++) { 440 if ('A' <= *q && *q <= 'Z') 441 *q = *q - 'A' + 'a'; 442 } 443 444 /* generate 8 bytes of pseudo-random value. */ 445 SHA512Init(&ctx); 446 SHA512Update(&ctx, &l, sizeof(l)); 447 SHA512Update(&ctx, n, l); 448 SHA512Final(digest, &ctx); 449 450 bzero(sa6, sizeof(*sa6)); 451 sa6->sin6_family = AF_INET6; 452 sa6->sin6_len = sizeof(*sa6); 453 sa6->sin6_addr.s6_addr16[0] = htons(0xff02); 454 sa6->sin6_addr.s6_addr16[1] = htons(ifp->if_index); 455 sa6->sin6_addr.s6_addr8[11] = 2; 456 bcopy(digest, &sa6->sin6_addr.s6_addr32[3], 457 sizeof(sa6->sin6_addr.s6_addr32[3])); 458 459 return 0; 460} 461 462/* 463 * XXX multiple loopback interface needs more care. for instance, 464 * nodelocal address needs to be configured onto only one of them. 465 * XXX multiple link-local address case 466 */ 467int 468in6_ifattach(struct ifnet *ifp) 469{ 470 /* some of the interfaces are inherently not IPv6 capable */ 471 switch (ifp->if_type) { 472 case IFT_BRIDGE: 473 case IFT_ENC: 474 case IFT_PFLOG: 475 case IFT_PFSYNC: 476 return (0); 477 } 478 479 /* 480 * if link mtu is too small, don't try to configure IPv6. 481 * remember there could be some link-layer that has special 482 * fragmentation logic. 483 */ 484 if (ifp->if_mtu < IPV6_MMTU) 485 return (EINVAL); 486 487 if ((ifp->if_flags & IFF_MULTICAST) == 0) 488 return (EINVAL); 489 490 /* Assign loopback address, if there's none. */ 491 if (ifp->if_flags & IFF_LOOPBACK) { 492 struct in6_addr in6 = in6addr_loopback; 493 int error; 494 495 if (in6ifa_ifpwithaddr(ifp, &in6) != NULL) 496 return (0); 497 498 error = in6_ifattach_loopback(ifp); 499 if (error) 500 return (error); 501 } 502 503 /* Assign a link-local address, if there's none. */ 504 if (in6ifa_ifpforlinklocal(ifp, 0) == NULL) { 505 if (in6_ifattach_linklocal(ifp, NULL) != 0) { 506 /* failed to assign linklocal address. bark? */ 507 } 508 } 509 510 if (ifp->if_xflags & IFXF_AUTOCONF6) 511 nd6_rs_attach(ifp); 512 513 return (0); 514} 515 516/* 517 * NOTE: in6_ifdetach() does not support loopback if at this moment. 518 */ 519void 520in6_ifdetach(struct ifnet *ifp) 521{ 522 struct ifaddr *ifa, *next; 523 struct rtentry *rt; 524 struct sockaddr_in6 sin6; 525 526#ifdef MROUTING 527 /* remove ip6_mrouter stuff */ 528 ip6_mrouter_detach(ifp); 529#endif 530 531 /* nuke any of IPv6 addresses we have */ 532 TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrlist, ifa_list, next) { 533 if (ifa->ifa_addr->sa_family != AF_INET6) 534 continue; 535 in6_purgeaddr(ifa); 536 dohooks(ifp->if_addrhooks, 0); 537 } 538 539 /* 540 * Remove neighbor management table. Must be called after 541 * purging addresses. 542 */ 543 nd6_purge(ifp); 544 545 /* remove route to interface local allnodes multicast (ff01::1) */ 546 bzero(&sin6, sizeof(sin6)); 547 sin6.sin6_len = sizeof(struct sockaddr_in6); 548 sin6.sin6_family = AF_INET6; 549 sin6.sin6_addr = in6addr_intfacelocal_allnodes; 550 sin6.sin6_addr.s6_addr16[1] = htons(ifp->if_index); 551 rt = rtalloc(sin6tosa(&sin6), 0, ifp->if_rdomain); 552 if (rt && rt->rt_ifidx == ifp->if_index) { 553 rtdeletemsg(rt, ifp, ifp->if_rdomain); 554 rtfree(rt); 555 } 556 557 /* remove route to link-local allnodes multicast (ff02::1) */ 558 bzero(&sin6, sizeof(sin6)); 559 sin6.sin6_len = sizeof(struct sockaddr_in6); 560 sin6.sin6_family = AF_INET6; 561 sin6.sin6_addr = in6addr_linklocal_allnodes; 562 sin6.sin6_addr.s6_addr16[1] = htons(ifp->if_index); 563 rt = rtalloc(sin6tosa(&sin6), 0, ifp->if_rdomain); 564 if (rt && rt->rt_ifidx == ifp->if_index) { 565 rtdeletemsg(rt, ifp, ifp->if_rdomain); 566 rtfree(rt); 567 } 568 569 if (ifp->if_xflags & IFXF_AUTOCONF6) { 570 nd6_rs_detach(ifp); 571 ifp->if_xflags &= ~IFXF_AUTOCONF6; 572 } 573} 574