1 /* $OpenBSD: in6_src.c,v 1.85 2021/03/10 10:21:49 jsg Exp $ */ 2 /* $KAME: in6_src.c,v 1.36 2001/02/06 04:08:17 itojun 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 /* 34 * Copyright (c) 1982, 1986, 1991, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 3. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 * 61 * @(#)in_pcb.c 8.2 (Berkeley) 1/4/94 62 */ 63 64 #include <sys/param.h> 65 #include <sys/systm.h> 66 #include <sys/mbuf.h> 67 #include <sys/protosw.h> 68 #include <sys/socket.h> 69 #include <sys/socketvar.h> 70 #include <sys/ioctl.h> 71 #include <sys/errno.h> 72 #include <sys/time.h> 73 74 #include <net/if.h> 75 #include <net/if_var.h> 76 #include <net/route.h> 77 78 #include <netinet/in.h> 79 #include <netinet/ip.h> 80 #include <netinet/in_pcb.h> 81 #include <netinet6/in6_var.h> 82 #include <netinet/ip6.h> 83 #include <netinet6/ip6_var.h> 84 #include <netinet6/nd6.h> 85 86 int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *, 87 struct ip6_moptions *, struct route_in6 *, struct ifnet **, u_int); 88 89 /* 90 * Return an IPv6 address, which is the most appropriate for a given 91 * destination and pcb. We need the additional opt parameter because 92 * the values set at pcb level can be overridden via cmsg. 93 */ 94 int 95 in6_pcbselsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock, 96 struct inpcb *inp, struct ip6_pktopts *opts) 97 { 98 struct ip6_moptions *mopts = inp->inp_moptions6; 99 struct route_in6 *ro = &inp->inp_route6; 100 struct in6_addr *laddr = &inp->inp_laddr6; 101 u_int rtableid = inp->inp_rtableid; 102 struct ifnet *ifp = NULL; 103 struct sockaddr *ip6_source = NULL; 104 struct in6_addr *dst; 105 struct in6_ifaddr *ia6 = NULL; 106 struct in6_pktinfo *pi = NULL; 107 int error; 108 109 dst = &dstsock->sin6_addr; 110 111 /* 112 * If the source address is explicitly specified by the caller, 113 * check if the requested source address is indeed a unicast address 114 * assigned to the node, and can be used as the packet's source 115 * address. If everything is okay, use the address as source. 116 */ 117 if (opts && (pi = opts->ip6po_pktinfo) && 118 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { 119 struct sockaddr_in6 sa6; 120 121 /* get the outgoing interface */ 122 error = in6_selectif(dstsock, opts, mopts, ro, &ifp, rtableid); 123 if (error) 124 return (error); 125 126 bzero(&sa6, sizeof(sa6)); 127 sa6.sin6_family = AF_INET6; 128 sa6.sin6_len = sizeof(sa6); 129 sa6.sin6_addr = pi->ipi6_addr; 130 131 if (ifp && IN6_IS_SCOPE_EMBED(&sa6.sin6_addr)) 132 sa6.sin6_addr.s6_addr16[1] = htons(ifp->if_index); 133 if_put(ifp); /* put reference from in6_selectif */ 134 135 ia6 = ifatoia6(ifa_ifwithaddr(sin6tosa(&sa6), rtableid)); 136 if (ia6 == NULL || (ia6->ia6_flags & 137 (IN6_IFF_ANYCAST|IN6_IFF_TENTATIVE|IN6_IFF_DUPLICATED))) 138 return (EADDRNOTAVAIL); 139 140 pi->ipi6_addr = sa6.sin6_addr; /* XXX: this overrides pi */ 141 142 *in6src = &pi->ipi6_addr; 143 return (0); 144 } 145 146 /* 147 * If the source address is not specified but the socket(if any) 148 * is already bound, use the bound address. 149 */ 150 if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) { 151 *in6src = laddr; 152 return (0); 153 } 154 155 /* 156 * If the caller doesn't specify the source address but 157 * the outgoing interface, use an address associated with 158 * the interface. 159 */ 160 if (pi && pi->ipi6_ifindex) { 161 ifp = if_get(pi->ipi6_ifindex); 162 if (ifp == NULL) 163 return (ENXIO); /* XXX: better error? */ 164 165 ia6 = in6_ifawithscope(ifp, dst, rtableid); 166 if_put(ifp); 167 168 if (ia6 == NULL) 169 return (EADDRNOTAVAIL); 170 171 *in6src = &ia6->ia_addr.sin6_addr; 172 return (0); 173 } 174 175 error = in6_selectsrc(in6src, dstsock, mopts, rtableid); 176 if (error != EADDRNOTAVAIL) 177 return (error); 178 179 /* 180 * If route is known or can be allocated now, 181 * our src addr is taken from the i/f, else punt. 182 */ 183 if (!rtisvalid(ro->ro_rt) || (ro->ro_tableid != rtableid) || 184 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) { 185 rtfree(ro->ro_rt); 186 ro->ro_rt = NULL; 187 } 188 if (ro->ro_rt == NULL) { 189 struct sockaddr_in6 *sa6; 190 191 /* No route yet, so try to acquire one */ 192 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 193 ro->ro_tableid = rtableid; 194 sa6 = &ro->ro_dst; 195 sa6->sin6_family = AF_INET6; 196 sa6->sin6_len = sizeof(struct sockaddr_in6); 197 sa6->sin6_addr = *dst; 198 sa6->sin6_scope_id = dstsock->sin6_scope_id; 199 ro->ro_rt = rtalloc(sin6tosa(&ro->ro_dst), 200 RT_RESOLVE, ro->ro_tableid); 201 } 202 203 /* 204 * in_pcbconnect() checks out IFF_LOOPBACK to skip using 205 * the address. But we don't know why it does so. 206 * It is necessary to ensure the scope even for lo0 207 * so doesn't check out IFF_LOOPBACK. 208 */ 209 210 if (ro->ro_rt) { 211 ifp = if_get(ro->ro_rt->rt_ifidx); 212 if (ifp != NULL) { 213 ia6 = in6_ifawithscope(ifp, dst, rtableid); 214 if_put(ifp); 215 } 216 if (ia6 == NULL) /* xxx scope error ?*/ 217 ia6 = ifatoia6(ro->ro_rt->rt_ifa); 218 } 219 220 /* 221 * Use preferred source address if : 222 * - destination is not onlink 223 * - preferred source address is set 224 * - output interface is UP 225 */ 226 if (ro->ro_rt && !(ro->ro_rt->rt_flags & RTF_LLINFO) && 227 !(ro->ro_rt->rt_flags & RTF_HOST)) { 228 ip6_source = rtable_getsource(rtableid, AF_INET6); 229 if (ip6_source != NULL) { 230 struct ifaddr *ifa; 231 if ((ifa = ifa_ifwithaddr(ip6_source, rtableid)) != 232 NULL && ISSET(ifa->ifa_ifp->if_flags, IFF_UP)) { 233 *in6src = &satosin6(ip6_source)->sin6_addr; 234 return (0); 235 } 236 } 237 } 238 239 if (ia6 == NULL) 240 return (EHOSTUNREACH); /* no route */ 241 242 *in6src = &ia6->ia_addr.sin6_addr; 243 return (0); 244 } 245 246 /* 247 * Return an IPv6 address, which is the most appropriate for a given 248 * destination and multicast options. 249 * If necessary, this function lookups the routing table and returns 250 * an entry to the caller for later use. 251 */ 252 int 253 in6_selectsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock, 254 struct ip6_moptions *mopts, unsigned int rtableid) 255 { 256 struct ifnet *ifp = NULL; 257 struct in6_addr *dst; 258 struct in6_ifaddr *ia6 = NULL; 259 260 dst = &dstsock->sin6_addr; 261 262 /* 263 * If the destination address is a link-local unicast address or 264 * a link/interface-local multicast address, and if the outgoing 265 * interface is specified by the sin6_scope_id filed, use an address 266 * associated with the interface. 267 * XXX: We're now trying to define more specific semantics of 268 * sin6_scope_id field, so this part will be rewritten in 269 * the near future. 270 */ 271 if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) || 272 IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) { 273 ifp = if_get(dstsock->sin6_scope_id); 274 if (ifp == NULL) 275 return (ENXIO); /* XXX: better error? */ 276 277 ia6 = in6_ifawithscope(ifp, dst, rtableid); 278 if_put(ifp); 279 280 if (ia6 == NULL) 281 return (EADDRNOTAVAIL); 282 283 *in6src = &ia6->ia_addr.sin6_addr; 284 return (0); 285 } 286 287 /* 288 * If the destination address is a multicast address and 289 * the outgoing interface for the address is specified 290 * by the caller, use an address associated with the interface. 291 * Even if the outgoing interface is not specified, we also 292 * choose a loopback interface as the outgoing interface. 293 */ 294 if (IN6_IS_ADDR_MULTICAST(dst)) { 295 ifp = mopts ? if_get(mopts->im6o_ifidx) : NULL; 296 297 if (!ifp && dstsock->sin6_scope_id) 298 ifp = if_get(htons(dstsock->sin6_scope_id)); 299 300 if (ifp) { 301 ia6 = in6_ifawithscope(ifp, dst, rtableid); 302 if_put(ifp); 303 304 if (ia6 == NULL) 305 return (EADDRNOTAVAIL); 306 307 *in6src = &ia6->ia_addr.sin6_addr; 308 return (0); 309 } 310 } 311 312 return (EADDRNOTAVAIL); 313 } 314 315 struct rtentry * 316 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 317 struct route_in6 *ro, unsigned int rtableid) 318 { 319 struct in6_addr *dst; 320 321 dst = &dstsock->sin6_addr; 322 323 /* 324 * Use a cached route if it exists and is valid, else try to allocate 325 * a new one. 326 */ 327 if (ro) { 328 if (rtisvalid(ro->ro_rt)) 329 KASSERT(sin6tosa(&ro->ro_dst)->sa_family == AF_INET6); 330 if (!rtisvalid(ro->ro_rt) || 331 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) { 332 rtfree(ro->ro_rt); 333 ro->ro_rt = NULL; 334 } 335 if (ro->ro_rt == NULL) { 336 struct sockaddr_in6 *sa6; 337 338 /* No route yet, so try to acquire one */ 339 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 340 ro->ro_tableid = rtableid; 341 sa6 = &ro->ro_dst; 342 *sa6 = *dstsock; 343 sa6->sin6_scope_id = 0; 344 ro->ro_tableid = rtableid; 345 ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst), 346 NULL, ro->ro_tableid); 347 } 348 349 /* 350 * Check if the outgoing interface conflicts with 351 * the interface specified by ipi6_ifindex (if specified). 352 * Note that loopback interface is always okay. 353 * (this may happen when we are sending a packet to one of 354 * our own addresses.) 355 */ 356 if (opts && opts->ip6po_pktinfo && 357 opts->ip6po_pktinfo->ipi6_ifindex) { 358 if (ro->ro_rt != NULL && 359 !ISSET(ro->ro_rt->rt_flags, RTF_LOCAL) && 360 ro->ro_rt->rt_ifidx != 361 opts->ip6po_pktinfo->ipi6_ifindex) { 362 return (NULL); 363 } 364 } 365 366 return (ro->ro_rt); 367 } 368 369 return (NULL); 370 } 371 372 int 373 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 374 struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp, 375 u_int rtableid) 376 { 377 struct rtentry *rt = NULL; 378 struct in6_pktinfo *pi = NULL; 379 380 /* If the caller specify the outgoing interface explicitly, use it. */ 381 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 382 *retifp = if_get(pi->ipi6_ifindex); 383 if (*retifp != NULL) 384 return (0); 385 } 386 387 /* 388 * If the destination address is a multicast address and the outgoing 389 * interface for the address is specified by the caller, use it. 390 */ 391 if (IN6_IS_ADDR_MULTICAST(&dstsock->sin6_addr) && 392 mopts != NULL && (*retifp = if_get(mopts->im6o_ifidx)) != NULL) 393 return (0); 394 395 rt = in6_selectroute(dstsock, opts, ro, rtableid); 396 if (rt == NULL) 397 return (EHOSTUNREACH); 398 399 /* 400 * do not use a rejected or black hole route. 401 * XXX: this check should be done in the L2 output routine. 402 * However, if we skipped this check here, we'd see the following 403 * scenario: 404 * - install a rejected route for a scoped address prefix 405 * (like fe80::/10) 406 * - send a packet to a destination that matches the scoped prefix, 407 * with ambiguity about the scope zone. 408 * - pick the outgoing interface from the route, and disambiguate the 409 * scope zone with the interface. 410 * - ip6_output() would try to get another route with the "new" 411 * destination, which may be valid. 412 * - we'd see no error on output. 413 * Although this may not be very harmful, it should still be confusing. 414 * We thus reject the case here. 415 */ 416 if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) 417 return (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 418 419 if (rt != NULL) 420 *retifp = if_get(rt->rt_ifidx); 421 422 return (0); 423 } 424 425 int 426 in6_selecthlim(struct inpcb *in6p) 427 { 428 if (in6p && in6p->inp_hops >= 0) 429 return (in6p->inp_hops); 430 431 return (ip6_defhlim); 432 } 433 434 /* 435 * generate kernel-internal form (scopeid embedded into s6_addr16[1]). 436 * If the address scope of is link-local, embed the interface index in the 437 * address. The routine determines our precedence 438 * between advanced API scope/interface specification and basic API 439 * specification. 440 * 441 * this function should be nuked in the future, when we get rid of 442 * embedded scopeid thing. 443 * 444 * XXX actually, it is over-specification to return ifp against sin6_scope_id. 445 * there can be multiple interfaces that belong to a particular scope zone 446 * (in specification, we have 1:N mapping between a scope zone and interfaces). 447 * we may want to change the function to return something other than ifp. 448 */ 449 int 450 in6_embedscope(struct in6_addr *in6, const struct sockaddr_in6 *sin6, 451 struct inpcb *in6p) 452 { 453 struct ifnet *ifp = NULL; 454 u_int32_t scopeid; 455 456 *in6 = sin6->sin6_addr; 457 scopeid = sin6->sin6_scope_id; 458 459 /* 460 * don't try to read sin6->sin6_addr beyond here, since the caller may 461 * ask us to overwrite existing sockaddr_in6 462 */ 463 464 if (IN6_IS_SCOPE_EMBED(in6)) { 465 struct in6_pktinfo *pi; 466 467 /* 468 * KAME assumption: link id == interface id 469 */ 470 471 if (in6p && in6p->inp_outputopts6 && 472 (pi = in6p->inp_outputopts6->ip6po_pktinfo) && 473 pi->ipi6_ifindex) { 474 ifp = if_get(pi->ipi6_ifindex); 475 if (ifp == NULL) 476 return ENXIO; /* XXX EINVAL? */ 477 in6->s6_addr16[1] = htons(pi->ipi6_ifindex); 478 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) && 479 in6p->inp_moptions6 && 480 (ifp = if_get(in6p->inp_moptions6->im6o_ifidx))) { 481 in6->s6_addr16[1] = htons(ifp->if_index); 482 } else if (scopeid) { 483 ifp = if_get(scopeid); 484 if (ifp == NULL) 485 return ENXIO; /* XXX EINVAL? */ 486 /*XXX assignment to 16bit from 32bit variable */ 487 in6->s6_addr16[1] = htons(scopeid & 0xffff); 488 } 489 if_put(ifp); 490 } 491 492 return 0; 493 } 494 495 /* 496 * generate standard sockaddr_in6 from embedded form. 497 * touches sin6_addr and sin6_scope_id only. 498 * 499 * this function should be nuked in the future, when we get rid of 500 * embedded scopeid thing. 501 */ 502 void 503 in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6) 504 { 505 u_int32_t scopeid; 506 507 sin6->sin6_addr = *in6; 508 509 /* 510 * don't try to read *in6 beyond here, since the caller may 511 * ask us to overwrite existing sockaddr_in6 512 */ 513 514 sin6->sin6_scope_id = 0; 515 if (IN6_IS_SCOPE_EMBED(in6)) { 516 /* 517 * KAME assumption: link id == interface id 518 */ 519 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]); 520 if (scopeid) { 521 sin6->sin6_addr.s6_addr16[1] = 0; 522 sin6->sin6_scope_id = scopeid; 523 } 524 } 525 } 526 527 /* 528 * just clear the embedded scope identifier. 529 */ 530 void 531 in6_clearscope(struct in6_addr *addr) 532 { 533 if (IN6_IS_SCOPE_EMBED(addr)) 534 addr->s6_addr16[1] = 0; 535 } 536