1 /* $OpenBSD: in6_src.c,v 1.74 2016/06/30 12:36:27 mpi 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 user specified options. 92 * If necessary, this function lookups the routing table and returns 93 * an entry to the caller for later use. 94 */ 95 int 96 in6_selectsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock, 97 struct ip6_pktopts *opts, struct ip6_moptions *mopts, 98 struct route_in6 *ro, struct in6_addr *laddr, u_int rtableid) 99 { 100 struct ifnet *ifp = NULL; 101 struct in6_addr *dst; 102 struct in6_ifaddr *ia6 = NULL; 103 struct in6_pktinfo *pi = NULL; 104 int error; 105 106 dst = &dstsock->sin6_addr; 107 108 /* 109 * If the source address is explicitly specified by the caller, 110 * check if the requested source address is indeed a unicast address 111 * assigned to the node, and can be used as the packet's source 112 * address. If everything is okay, use the address as source. 113 */ 114 if (opts && (pi = opts->ip6po_pktinfo) && 115 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { 116 struct sockaddr_in6 sa6; 117 118 /* get the outgoing interface */ 119 error = in6_selectif(dstsock, opts, mopts, ro, &ifp, rtableid); 120 if (error) 121 return (error); 122 123 bzero(&sa6, sizeof(sa6)); 124 sa6.sin6_family = AF_INET6; 125 sa6.sin6_len = sizeof(sa6); 126 sa6.sin6_addr = pi->ipi6_addr; 127 128 if (ifp && IN6_IS_SCOPE_EMBED(&sa6.sin6_addr)) 129 sa6.sin6_addr.s6_addr16[1] = htons(ifp->if_index); 130 if_put(ifp); /* put reference from in6_selectif */ 131 132 ia6 = ifatoia6(ifa_ifwithaddr(sin6tosa(&sa6), rtableid)); 133 if (ia6 == NULL || 134 (ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) 135 return (EADDRNOTAVAIL); 136 137 pi->ipi6_addr = sa6.sin6_addr; /* XXX: this overrides pi */ 138 139 *in6src = &pi->ipi6_addr; 140 return (0); 141 } 142 143 /* 144 * If the source address is not specified but the socket(if any) 145 * is already bound, use the bound address. 146 */ 147 if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) { 148 *in6src = laddr; 149 return (0); 150 } 151 152 /* 153 * If the caller doesn't specify the source address but 154 * the outgoing interface, use an address associated with 155 * the interface. 156 */ 157 if (pi && pi->ipi6_ifindex) { 158 ifp = if_get(pi->ipi6_ifindex); 159 if (ifp == NULL) 160 return (ENXIO); /* XXX: better error? */ 161 162 ia6 = in6_ifawithscope(ifp, dst, rtableid); 163 if_put(ifp); 164 165 if (ia6 == NULL) 166 return (EADDRNOTAVAIL); 167 168 *in6src = &ia6->ia_addr.sin6_addr; 169 return (0); 170 } 171 172 /* 173 * If the destination address is a link-local unicast address or 174 * a link/interface-local multicast address, and if the outgoing 175 * interface is specified by the sin6_scope_id filed, use an address 176 * associated with the interface. 177 * XXX: We're now trying to define more specific semantics of 178 * sin6_scope_id field, so this part will be rewritten in 179 * the near future. 180 */ 181 if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) || 182 IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) { 183 ifp = if_get(dstsock->sin6_scope_id); 184 if (ifp == NULL) 185 return (ENXIO); /* XXX: better error? */ 186 187 ia6 = in6_ifawithscope(ifp, dst, rtableid); 188 if_put(ifp); 189 190 if (ia6 == NULL) 191 return (EADDRNOTAVAIL); 192 193 *in6src = &ia6->ia_addr.sin6_addr; 194 return (0); 195 } 196 197 /* 198 * If the destination address is a multicast address and 199 * the outgoing interface for the address is specified 200 * by the caller, use an address associated with the interface. 201 * Even if the outgoing interface is not specified, we also 202 * choose a loopback interface as the outgoing interface. 203 */ 204 if (IN6_IS_ADDR_MULTICAST(dst)) { 205 ifp = mopts ? if_get(mopts->im6o_ifidx) : NULL; 206 207 if (!ifp && dstsock->sin6_scope_id) 208 ifp = if_get(htons(dstsock->sin6_scope_id)); 209 210 if (ifp) { 211 ia6 = in6_ifawithscope(ifp, dst, rtableid); 212 if_put(ifp); 213 214 if (ia6 == NULL) 215 return (EADDRNOTAVAIL); 216 217 *in6src = &ia6->ia_addr.sin6_addr; 218 return (0); 219 } 220 } 221 222 /* 223 * If route is known or can be allocated now, 224 * our src addr is taken from the i/f, else punt. 225 */ 226 if (ro) { 227 if (!rtisvalid(ro->ro_rt) || (ro->ro_tableid != rtableid) || 228 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) { 229 rtfree(ro->ro_rt); 230 ro->ro_rt = NULL; 231 } 232 if (ro->ro_rt == NULL) { 233 struct sockaddr_in6 *sa6; 234 235 /* No route yet, so try to acquire one */ 236 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 237 ro->ro_tableid = rtableid; 238 sa6 = &ro->ro_dst; 239 sa6->sin6_family = AF_INET6; 240 sa6->sin6_len = sizeof(struct sockaddr_in6); 241 sa6->sin6_addr = *dst; 242 sa6->sin6_scope_id = dstsock->sin6_scope_id; 243 ro->ro_rt = rtalloc(sin6tosa(&ro->ro_dst), 244 RT_RESOLVE, ro->ro_tableid); 245 } 246 247 /* 248 * in_pcbconnect() checks out IFF_LOOPBACK to skip using 249 * the address. But we don't know why it does so. 250 * It is necessary to ensure the scope even for lo0 251 * so doesn't check out IFF_LOOPBACK. 252 */ 253 254 if (ro->ro_rt) { 255 ifp = if_get(ro->ro_rt->rt_ifidx); 256 if (ifp != NULL) { 257 ia6 = in6_ifawithscope(ifp, dst, rtableid); 258 if_put(ifp); 259 } 260 if (ia6 == NULL) { /* xxx scope error ?*/ 261 *in6src = 262 &satosin6(ro->ro_rt->rt_addr)->sin6_addr; 263 return (0); 264 } 265 } 266 if (ia6 == NULL) 267 return (EHOSTUNREACH); /* no route */ 268 269 *in6src = &ia6->ia_addr.sin6_addr; 270 return (0); 271 } 272 273 return (EADDRNOTAVAIL); 274 } 275 276 struct rtentry * 277 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 278 struct route_in6 *ro, unsigned int rtableid) 279 { 280 struct in6_addr *dst; 281 282 dst = &dstsock->sin6_addr; 283 284 /* 285 * Use a cached route if it exists and is valid, else try to allocate 286 * a new one. Note that we should check the address family of the 287 * cached destination, in case of sharing the cache with IPv4. 288 */ 289 if (ro) { 290 if (!rtisvalid(ro->ro_rt) || 291 sin6tosa(&ro->ro_dst)->sa_family != AF_INET6 || 292 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) { 293 rtfree(ro->ro_rt); 294 ro->ro_rt = NULL; 295 } 296 if (ro->ro_rt == NULL) { 297 struct sockaddr_in6 *sa6; 298 299 /* No route yet, so try to acquire one */ 300 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 301 ro->ro_tableid = rtableid; 302 sa6 = &ro->ro_dst; 303 *sa6 = *dstsock; 304 sa6->sin6_scope_id = 0; 305 ro->ro_tableid = rtableid; 306 ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst), 307 NULL, ro->ro_tableid); 308 } 309 310 /* 311 * Check if the outgoing interface conflicts with 312 * the interface specified by ipi6_ifindex (if specified). 313 * Note that loopback interface is always okay. 314 * (this may happen when we are sending a packet to one of 315 * our own addresses.) 316 */ 317 if (opts && opts->ip6po_pktinfo && 318 opts->ip6po_pktinfo->ipi6_ifindex) { 319 if (ro->ro_rt != NULL && 320 !ISSET(ro->ro_rt->rt_flags, RTF_LOCAL) && 321 ro->ro_rt->rt_ifidx != 322 opts->ip6po_pktinfo->ipi6_ifindex) { 323 return (NULL); 324 } 325 } 326 327 return (ro->ro_rt); 328 } 329 330 return (NULL); 331 } 332 333 int 334 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 335 struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp, 336 u_int rtableid) 337 { 338 struct rtentry *rt = NULL; 339 struct in6_pktinfo *pi = NULL; 340 341 /* If the caller specify the outgoing interface explicitly, use it. */ 342 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 343 *retifp = if_get(pi->ipi6_ifindex); 344 if (*retifp != NULL) 345 return (0); 346 } 347 348 /* 349 * If the destination address is a multicast address and the outgoing 350 * interface for the address is specified by the caller, use it. 351 */ 352 if (IN6_IS_ADDR_MULTICAST(&dstsock->sin6_addr) && 353 mopts != NULL && (*retifp = if_get(mopts->im6o_ifidx)) != NULL) 354 return (0); 355 356 rt = in6_selectroute(dstsock, opts, ro, rtableid); 357 if (rt == NULL) 358 return (EHOSTUNREACH); 359 360 /* 361 * do not use a rejected or black hole route. 362 * XXX: this check should be done in the L2 output routine. 363 * However, if we skipped this check here, we'd see the following 364 * scenario: 365 * - install a rejected route for a scoped address prefix 366 * (like fe80::/10) 367 * - send a packet to a destination that matches the scoped prefix, 368 * with ambiguity about the scope zone. 369 * - pick the outgoing interface from the route, and disambiguate the 370 * scope zone with the interface. 371 * - ip6_output() would try to get another route with the "new" 372 * destination, which may be valid. 373 * - we'd see no error on output. 374 * Although this may not be very harmful, it should still be confusing. 375 * We thus reject the case here. 376 */ 377 if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) 378 return (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 379 380 if (rt != NULL) 381 *retifp = if_get(rt->rt_ifidx); 382 383 return (0); 384 } 385 386 int 387 in6_selecthlim(struct inpcb *in6p) 388 { 389 if (in6p && in6p->inp_hops >= 0) 390 return (in6p->inp_hops); 391 392 return (ip6_defhlim); 393 } 394 395 /* 396 * generate kernel-internal form (scopeid embedded into s6_addr16[1]). 397 * If the address scope of is link-local, embed the interface index in the 398 * address. The routine determines our precedence 399 * between advanced API scope/interface specification and basic API 400 * specification. 401 * 402 * this function should be nuked in the future, when we get rid of 403 * embedded scopeid thing. 404 * 405 * XXX actually, it is over-specification to return ifp against sin6_scope_id. 406 * there can be multiple interfaces that belong to a particular scope zone 407 * (in specification, we have 1:N mapping between a scope zone and interfaces). 408 * we may want to change the function to return something other than ifp. 409 */ 410 int 411 in6_embedscope(struct in6_addr *in6, const struct sockaddr_in6 *sin6, 412 struct inpcb *in6p) 413 { 414 struct ifnet *ifp = NULL; 415 u_int32_t scopeid; 416 417 *in6 = sin6->sin6_addr; 418 scopeid = sin6->sin6_scope_id; 419 420 /* 421 * don't try to read sin6->sin6_addr beyond here, since the caller may 422 * ask us to overwrite existing sockaddr_in6 423 */ 424 425 if (IN6_IS_SCOPE_EMBED(in6)) { 426 struct in6_pktinfo *pi; 427 428 /* 429 * KAME assumption: link id == interface id 430 */ 431 432 if (in6p && in6p->inp_outputopts6 && 433 (pi = in6p->inp_outputopts6->ip6po_pktinfo) && 434 pi->ipi6_ifindex) { 435 ifp = if_get(pi->ipi6_ifindex); 436 if (ifp == NULL) 437 return ENXIO; /* XXX EINVAL? */ 438 in6->s6_addr16[1] = htons(pi->ipi6_ifindex); 439 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) && 440 in6p->inp_moptions6 && 441 (ifp = if_get(in6p->inp_moptions6->im6o_ifidx))) { 442 in6->s6_addr16[1] = htons(ifp->if_index); 443 } else if (scopeid) { 444 ifp = if_get(scopeid); 445 if (ifp == NULL) 446 return ENXIO; /* XXX EINVAL? */ 447 /*XXX assignment to 16bit from 32bit variable */ 448 in6->s6_addr16[1] = htons(scopeid & 0xffff); 449 } 450 if_put(ifp); 451 } 452 453 return 0; 454 } 455 456 /* 457 * generate standard sockaddr_in6 from embedded form. 458 * touches sin6_addr and sin6_scope_id only. 459 * 460 * this function should be nuked in the future, when we get rid of 461 * embedded scopeid thing. 462 */ 463 void 464 in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6) 465 { 466 u_int32_t scopeid; 467 468 sin6->sin6_addr = *in6; 469 470 /* 471 * don't try to read *in6 beyond here, since the caller may 472 * ask us to overwrite existing sockaddr_in6 473 */ 474 475 sin6->sin6_scope_id = 0; 476 if (IN6_IS_SCOPE_EMBED(in6)) { 477 /* 478 * KAME assumption: link id == interface id 479 */ 480 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]); 481 if (scopeid) { 482 sin6->sin6_addr.s6_addr16[1] = 0; 483 sin6->sin6_scope_id = scopeid; 484 } 485 } 486 } 487 488 /* 489 * just clear the embedded scope identifer. 490 */ 491 void 492 in6_clearscope(struct in6_addr *addr) 493 { 494 if (IN6_IS_SCOPE_EMBED(addr)) 495 addr->s6_addr16[1] = 0; 496 } 497