1 /* $OpenBSD: in6_src.c,v 1.81 2016/12/02 11:16:04 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 pcb. We need the additional opt parameter because 92 * the values set at pcb level can be overriden 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 in6_addr *dst; 104 struct in6_ifaddr *ia6 = NULL; 105 struct in6_pktinfo *pi = NULL; 106 int error; 107 108 dst = &dstsock->sin6_addr; 109 110 /* 111 * If the source address is explicitly specified by the caller, 112 * check if the requested source address is indeed a unicast address 113 * assigned to the node, and can be used as the packet's source 114 * address. If everything is okay, use the address as source. 115 */ 116 if (opts && (pi = opts->ip6po_pktinfo) && 117 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { 118 struct sockaddr_in6 sa6; 119 120 /* get the outgoing interface */ 121 error = in6_selectif(dstsock, opts, mopts, ro, &ifp, rtableid); 122 if (error) 123 return (error); 124 125 bzero(&sa6, sizeof(sa6)); 126 sa6.sin6_family = AF_INET6; 127 sa6.sin6_len = sizeof(sa6); 128 sa6.sin6_addr = pi->ipi6_addr; 129 130 if (ifp && IN6_IS_SCOPE_EMBED(&sa6.sin6_addr)) 131 sa6.sin6_addr.s6_addr16[1] = htons(ifp->if_index); 132 if_put(ifp); /* put reference from in6_selectif */ 133 134 ia6 = ifatoia6(ifa_ifwithaddr(sin6tosa(&sa6), rtableid)); 135 if (ia6 == NULL || (ia6->ia6_flags & 136 (IN6_IFF_ANYCAST|IN6_IFF_TENTATIVE|IN6_IFF_DUPLICATED))) 137 return (EADDRNOTAVAIL); 138 139 pi->ipi6_addr = sa6.sin6_addr; /* XXX: this overrides pi */ 140 141 *in6src = &pi->ipi6_addr; 142 return (0); 143 } 144 145 /* 146 * If the source address is not specified but the socket(if any) 147 * is already bound, use the bound address. 148 */ 149 if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) { 150 *in6src = laddr; 151 return (0); 152 } 153 154 /* 155 * If the caller doesn't specify the source address but 156 * the outgoing interface, use an address associated with 157 * the interface. 158 */ 159 if (pi && pi->ipi6_ifindex) { 160 ifp = if_get(pi->ipi6_ifindex); 161 if (ifp == NULL) 162 return (ENXIO); /* XXX: better error? */ 163 164 ia6 = in6_ifawithscope(ifp, dst, rtableid); 165 if_put(ifp); 166 167 if (ia6 == NULL) 168 return (EADDRNOTAVAIL); 169 170 *in6src = &ia6->ia_addr.sin6_addr; 171 return (0); 172 } 173 174 error = in6_selectsrc(in6src, dstsock, mopts, rtableid); 175 if (error != EADDRNOTAVAIL) 176 return (error); 177 178 /* 179 * If route is known or can be allocated now, 180 * our src addr is taken from the i/f, else punt. 181 */ 182 if (!rtisvalid(ro->ro_rt) || (ro->ro_tableid != rtableid) || 183 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) { 184 rtfree(ro->ro_rt); 185 ro->ro_rt = NULL; 186 } 187 if (ro->ro_rt == NULL) { 188 struct sockaddr_in6 *sa6; 189 190 /* No route yet, so try to acquire one */ 191 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 192 ro->ro_tableid = rtableid; 193 sa6 = &ro->ro_dst; 194 sa6->sin6_family = AF_INET6; 195 sa6->sin6_len = sizeof(struct sockaddr_in6); 196 sa6->sin6_addr = *dst; 197 sa6->sin6_scope_id = dstsock->sin6_scope_id; 198 ro->ro_rt = rtalloc(sin6tosa(&ro->ro_dst), 199 RT_RESOLVE, ro->ro_tableid); 200 } 201 202 /* 203 * in_pcbconnect() checks out IFF_LOOPBACK to skip using 204 * the address. But we don't know why it does so. 205 * It is necessary to ensure the scope even for lo0 206 * so doesn't check out IFF_LOOPBACK. 207 */ 208 209 if (ro->ro_rt) { 210 ifp = if_get(ro->ro_rt->rt_ifidx); 211 if (ifp != NULL) { 212 ia6 = in6_ifawithscope(ifp, dst, rtableid); 213 if_put(ifp); 214 } 215 if (ia6 == NULL) /* xxx scope error ?*/ 216 ia6 = ifatoia6(ro->ro_rt->rt_ifa); 217 } 218 if (ia6 == NULL) 219 return (EHOSTUNREACH); /* no route */ 220 221 *in6src = &ia6->ia_addr.sin6_addr; 222 return (0); 223 } 224 225 /* 226 * Return an IPv6 address, which is the most appropriate for a given 227 * destination and multicast options. 228 * If necessary, this function lookups the routing table and returns 229 * an entry to the caller for later use. 230 */ 231 int 232 in6_selectsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock, 233 struct ip6_moptions *mopts, unsigned int rtableid) 234 { 235 struct ifnet *ifp = NULL; 236 struct in6_addr *dst; 237 struct in6_ifaddr *ia6 = NULL; 238 239 dst = &dstsock->sin6_addr; 240 241 /* 242 * If the destination address is a link-local unicast address or 243 * a link/interface-local multicast address, and if the outgoing 244 * interface is specified by the sin6_scope_id filed, use an address 245 * associated with the interface. 246 * XXX: We're now trying to define more specific semantics of 247 * sin6_scope_id field, so this part will be rewritten in 248 * the near future. 249 */ 250 if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) || 251 IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) { 252 ifp = if_get(dstsock->sin6_scope_id); 253 if (ifp == NULL) 254 return (ENXIO); /* XXX: better error? */ 255 256 ia6 = in6_ifawithscope(ifp, dst, rtableid); 257 if_put(ifp); 258 259 if (ia6 == NULL) 260 return (EADDRNOTAVAIL); 261 262 *in6src = &ia6->ia_addr.sin6_addr; 263 return (0); 264 } 265 266 /* 267 * If the destination address is a multicast address and 268 * the outgoing interface for the address is specified 269 * by the caller, use an address associated with the interface. 270 * Even if the outgoing interface is not specified, we also 271 * choose a loopback interface as the outgoing interface. 272 */ 273 if (IN6_IS_ADDR_MULTICAST(dst)) { 274 ifp = mopts ? if_get(mopts->im6o_ifidx) : NULL; 275 276 if (!ifp && dstsock->sin6_scope_id) 277 ifp = if_get(htons(dstsock->sin6_scope_id)); 278 279 if (ifp) { 280 ia6 = in6_ifawithscope(ifp, dst, rtableid); 281 if_put(ifp); 282 283 if (ia6 == NULL) 284 return (EADDRNOTAVAIL); 285 286 *in6src = &ia6->ia_addr.sin6_addr; 287 return (0); 288 } 289 } 290 291 return (EADDRNOTAVAIL); 292 } 293 294 struct rtentry * 295 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 296 struct route_in6 *ro, unsigned int rtableid) 297 { 298 struct in6_addr *dst; 299 300 dst = &dstsock->sin6_addr; 301 302 /* 303 * Use a cached route if it exists and is valid, else try to allocate 304 * a new one. 305 */ 306 if (ro) { 307 if (rtisvalid(ro->ro_rt)) 308 KASSERT(sin6tosa(&ro->ro_dst)->sa_family == AF_INET6); 309 if (!rtisvalid(ro->ro_rt) || 310 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) { 311 rtfree(ro->ro_rt); 312 ro->ro_rt = NULL; 313 } 314 if (ro->ro_rt == NULL) { 315 struct sockaddr_in6 *sa6; 316 317 /* No route yet, so try to acquire one */ 318 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 319 ro->ro_tableid = rtableid; 320 sa6 = &ro->ro_dst; 321 *sa6 = *dstsock; 322 sa6->sin6_scope_id = 0; 323 ro->ro_tableid = rtableid; 324 ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst), 325 NULL, ro->ro_tableid); 326 } 327 328 /* 329 * Check if the outgoing interface conflicts with 330 * the interface specified by ipi6_ifindex (if specified). 331 * Note that loopback interface is always okay. 332 * (this may happen when we are sending a packet to one of 333 * our own addresses.) 334 */ 335 if (opts && opts->ip6po_pktinfo && 336 opts->ip6po_pktinfo->ipi6_ifindex) { 337 if (ro->ro_rt != NULL && 338 !ISSET(ro->ro_rt->rt_flags, RTF_LOCAL) && 339 ro->ro_rt->rt_ifidx != 340 opts->ip6po_pktinfo->ipi6_ifindex) { 341 return (NULL); 342 } 343 } 344 345 return (ro->ro_rt); 346 } 347 348 return (NULL); 349 } 350 351 int 352 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 353 struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp, 354 u_int rtableid) 355 { 356 struct rtentry *rt = NULL; 357 struct in6_pktinfo *pi = NULL; 358 359 /* If the caller specify the outgoing interface explicitly, use it. */ 360 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 361 *retifp = if_get(pi->ipi6_ifindex); 362 if (*retifp != NULL) 363 return (0); 364 } 365 366 /* 367 * If the destination address is a multicast address and the outgoing 368 * interface for the address is specified by the caller, use it. 369 */ 370 if (IN6_IS_ADDR_MULTICAST(&dstsock->sin6_addr) && 371 mopts != NULL && (*retifp = if_get(mopts->im6o_ifidx)) != NULL) 372 return (0); 373 374 rt = in6_selectroute(dstsock, opts, ro, rtableid); 375 if (rt == NULL) 376 return (EHOSTUNREACH); 377 378 /* 379 * do not use a rejected or black hole route. 380 * XXX: this check should be done in the L2 output routine. 381 * However, if we skipped this check here, we'd see the following 382 * scenario: 383 * - install a rejected route for a scoped address prefix 384 * (like fe80::/10) 385 * - send a packet to a destination that matches the scoped prefix, 386 * with ambiguity about the scope zone. 387 * - pick the outgoing interface from the route, and disambiguate the 388 * scope zone with the interface. 389 * - ip6_output() would try to get another route with the "new" 390 * destination, which may be valid. 391 * - we'd see no error on output. 392 * Although this may not be very harmful, it should still be confusing. 393 * We thus reject the case here. 394 */ 395 if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) 396 return (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 397 398 if (rt != NULL) 399 *retifp = if_get(rt->rt_ifidx); 400 401 return (0); 402 } 403 404 int 405 in6_selecthlim(struct inpcb *in6p) 406 { 407 if (in6p && in6p->inp_hops >= 0) 408 return (in6p->inp_hops); 409 410 return (ip6_defhlim); 411 } 412 413 /* 414 * generate kernel-internal form (scopeid embedded into s6_addr16[1]). 415 * If the address scope of is link-local, embed the interface index in the 416 * address. The routine determines our precedence 417 * between advanced API scope/interface specification and basic API 418 * specification. 419 * 420 * this function should be nuked in the future, when we get rid of 421 * embedded scopeid thing. 422 * 423 * XXX actually, it is over-specification to return ifp against sin6_scope_id. 424 * there can be multiple interfaces that belong to a particular scope zone 425 * (in specification, we have 1:N mapping between a scope zone and interfaces). 426 * we may want to change the function to return something other than ifp. 427 */ 428 int 429 in6_embedscope(struct in6_addr *in6, const struct sockaddr_in6 *sin6, 430 struct inpcb *in6p) 431 { 432 struct ifnet *ifp = NULL; 433 u_int32_t scopeid; 434 435 *in6 = sin6->sin6_addr; 436 scopeid = sin6->sin6_scope_id; 437 438 /* 439 * don't try to read sin6->sin6_addr beyond here, since the caller may 440 * ask us to overwrite existing sockaddr_in6 441 */ 442 443 if (IN6_IS_SCOPE_EMBED(in6)) { 444 struct in6_pktinfo *pi; 445 446 /* 447 * KAME assumption: link id == interface id 448 */ 449 450 if (in6p && in6p->inp_outputopts6 && 451 (pi = in6p->inp_outputopts6->ip6po_pktinfo) && 452 pi->ipi6_ifindex) { 453 ifp = if_get(pi->ipi6_ifindex); 454 if (ifp == NULL) 455 return ENXIO; /* XXX EINVAL? */ 456 in6->s6_addr16[1] = htons(pi->ipi6_ifindex); 457 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) && 458 in6p->inp_moptions6 && 459 (ifp = if_get(in6p->inp_moptions6->im6o_ifidx))) { 460 in6->s6_addr16[1] = htons(ifp->if_index); 461 } else if (scopeid) { 462 ifp = if_get(scopeid); 463 if (ifp == NULL) 464 return ENXIO; /* XXX EINVAL? */ 465 /*XXX assignment to 16bit from 32bit variable */ 466 in6->s6_addr16[1] = htons(scopeid & 0xffff); 467 } 468 if_put(ifp); 469 } 470 471 return 0; 472 } 473 474 /* 475 * generate standard sockaddr_in6 from embedded form. 476 * touches sin6_addr and sin6_scope_id only. 477 * 478 * this function should be nuked in the future, when we get rid of 479 * embedded scopeid thing. 480 */ 481 void 482 in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6) 483 { 484 u_int32_t scopeid; 485 486 sin6->sin6_addr = *in6; 487 488 /* 489 * don't try to read *in6 beyond here, since the caller may 490 * ask us to overwrite existing sockaddr_in6 491 */ 492 493 sin6->sin6_scope_id = 0; 494 if (IN6_IS_SCOPE_EMBED(in6)) { 495 /* 496 * KAME assumption: link id == interface id 497 */ 498 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]); 499 if (scopeid) { 500 sin6->sin6_addr.s6_addr16[1] = 0; 501 sin6->sin6_scope_id = scopeid; 502 } 503 } 504 } 505 506 /* 507 * just clear the embedded scope identifer. 508 */ 509 void 510 in6_clearscope(struct in6_addr *addr) 511 { 512 if (IN6_IS_SCOPE_EMBED(addr)) 513 addr->s6_addr16[1] = 0; 514 } 515