1 /* $OpenBSD: in6_src.c,v 1.80 2016/09/02 13:53:44 vgross 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; 102 103 struct ifnet *ifp = 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 return in6_selectsrc(in6src, dstsock, mopts, ro, rtableid); 176 } 177 178 /* 179 * Return an IPv6 address, which is the most appropriate for a given 180 * destination and multicast options. 181 * If necessary, this function lookups the routing table and returns 182 * an entry to the caller for later use. 183 */ 184 int 185 in6_selectsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock, 186 struct ip6_moptions *mopts, struct route_in6 *ro, u_int rtableid) 187 { 188 struct ifnet *ifp = NULL; 189 struct in6_addr *dst; 190 struct in6_ifaddr *ia6 = NULL; 191 192 dst = &dstsock->sin6_addr; 193 194 /* 195 * If the destination address is a link-local unicast address or 196 * a link/interface-local multicast address, and if the outgoing 197 * interface is specified by the sin6_scope_id filed, use an address 198 * associated with the interface. 199 * XXX: We're now trying to define more specific semantics of 200 * sin6_scope_id field, so this part will be rewritten in 201 * the near future. 202 */ 203 if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) || 204 IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) { 205 ifp = if_get(dstsock->sin6_scope_id); 206 if (ifp == NULL) 207 return (ENXIO); /* XXX: better error? */ 208 209 ia6 = in6_ifawithscope(ifp, dst, rtableid); 210 if_put(ifp); 211 212 if (ia6 == NULL) 213 return (EADDRNOTAVAIL); 214 215 *in6src = &ia6->ia_addr.sin6_addr; 216 return (0); 217 } 218 219 /* 220 * If the destination address is a multicast address and 221 * the outgoing interface for the address is specified 222 * by the caller, use an address associated with the interface. 223 * Even if the outgoing interface is not specified, we also 224 * choose a loopback interface as the outgoing interface. 225 */ 226 if (IN6_IS_ADDR_MULTICAST(dst)) { 227 ifp = mopts ? if_get(mopts->im6o_ifidx) : NULL; 228 229 if (!ifp && dstsock->sin6_scope_id) 230 ifp = if_get(htons(dstsock->sin6_scope_id)); 231 232 if (ifp) { 233 ia6 = in6_ifawithscope(ifp, dst, rtableid); 234 if_put(ifp); 235 236 if (ia6 == NULL) 237 return (EADDRNOTAVAIL); 238 239 *in6src = &ia6->ia_addr.sin6_addr; 240 return (0); 241 } 242 } 243 244 /* 245 * If route is known or can be allocated now, 246 * our src addr is taken from the i/f, else punt. 247 */ 248 if (ro) { 249 if (!rtisvalid(ro->ro_rt) || (ro->ro_tableid != rtableid) || 250 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) { 251 rtfree(ro->ro_rt); 252 ro->ro_rt = NULL; 253 } 254 if (ro->ro_rt == NULL) { 255 struct sockaddr_in6 *sa6; 256 257 /* No route yet, so try to acquire one */ 258 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 259 ro->ro_tableid = rtableid; 260 sa6 = &ro->ro_dst; 261 sa6->sin6_family = AF_INET6; 262 sa6->sin6_len = sizeof(struct sockaddr_in6); 263 sa6->sin6_addr = *dst; 264 sa6->sin6_scope_id = dstsock->sin6_scope_id; 265 ro->ro_rt = rtalloc(sin6tosa(&ro->ro_dst), 266 RT_RESOLVE, ro->ro_tableid); 267 } 268 269 /* 270 * in_pcbconnect() checks out IFF_LOOPBACK to skip using 271 * the address. But we don't know why it does so. 272 * It is necessary to ensure the scope even for lo0 273 * so doesn't check out IFF_LOOPBACK. 274 */ 275 276 if (ro->ro_rt) { 277 ifp = if_get(ro->ro_rt->rt_ifidx); 278 if (ifp != NULL) { 279 ia6 = in6_ifawithscope(ifp, dst, rtableid); 280 if_put(ifp); 281 } 282 if (ia6 == NULL) /* xxx scope error ?*/ 283 ia6 = ifatoia6(ro->ro_rt->rt_ifa); 284 } 285 if (ia6 == NULL) 286 return (EHOSTUNREACH); /* no route */ 287 288 *in6src = &ia6->ia_addr.sin6_addr; 289 return (0); 290 } 291 292 return (EADDRNOTAVAIL); 293 } 294 295 struct rtentry * 296 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 297 struct route_in6 *ro, unsigned int rtableid) 298 { 299 struct in6_addr *dst; 300 301 dst = &dstsock->sin6_addr; 302 303 /* 304 * Use a cached route if it exists and is valid, else try to allocate 305 * a new one. 306 */ 307 if (ro) { 308 if (rtisvalid(ro->ro_rt)) 309 KASSERT(sin6tosa(&ro->ro_dst)->sa_family == AF_INET6); 310 if (!rtisvalid(ro->ro_rt) || 311 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) { 312 rtfree(ro->ro_rt); 313 ro->ro_rt = NULL; 314 } 315 if (ro->ro_rt == NULL) { 316 struct sockaddr_in6 *sa6; 317 318 /* No route yet, so try to acquire one */ 319 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 320 ro->ro_tableid = rtableid; 321 sa6 = &ro->ro_dst; 322 *sa6 = *dstsock; 323 sa6->sin6_scope_id = 0; 324 ro->ro_tableid = rtableid; 325 ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst), 326 NULL, ro->ro_tableid); 327 } 328 329 /* 330 * Check if the outgoing interface conflicts with 331 * the interface specified by ipi6_ifindex (if specified). 332 * Note that loopback interface is always okay. 333 * (this may happen when we are sending a packet to one of 334 * our own addresses.) 335 */ 336 if (opts && opts->ip6po_pktinfo && 337 opts->ip6po_pktinfo->ipi6_ifindex) { 338 if (ro->ro_rt != NULL && 339 !ISSET(ro->ro_rt->rt_flags, RTF_LOCAL) && 340 ro->ro_rt->rt_ifidx != 341 opts->ip6po_pktinfo->ipi6_ifindex) { 342 return (NULL); 343 } 344 } 345 346 return (ro->ro_rt); 347 } 348 349 return (NULL); 350 } 351 352 int 353 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 354 struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp, 355 u_int rtableid) 356 { 357 struct rtentry *rt = NULL; 358 struct in6_pktinfo *pi = NULL; 359 360 /* If the caller specify the outgoing interface explicitly, use it. */ 361 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 362 *retifp = if_get(pi->ipi6_ifindex); 363 if (*retifp != NULL) 364 return (0); 365 } 366 367 /* 368 * If the destination address is a multicast address and the outgoing 369 * interface for the address is specified by the caller, use it. 370 */ 371 if (IN6_IS_ADDR_MULTICAST(&dstsock->sin6_addr) && 372 mopts != NULL && (*retifp = if_get(mopts->im6o_ifidx)) != NULL) 373 return (0); 374 375 rt = in6_selectroute(dstsock, opts, ro, rtableid); 376 if (rt == NULL) 377 return (EHOSTUNREACH); 378 379 /* 380 * do not use a rejected or black hole route. 381 * XXX: this check should be done in the L2 output routine. 382 * However, if we skipped this check here, we'd see the following 383 * scenario: 384 * - install a rejected route for a scoped address prefix 385 * (like fe80::/10) 386 * - send a packet to a destination that matches the scoped prefix, 387 * with ambiguity about the scope zone. 388 * - pick the outgoing interface from the route, and disambiguate the 389 * scope zone with the interface. 390 * - ip6_output() would try to get another route with the "new" 391 * destination, which may be valid. 392 * - we'd see no error on output. 393 * Although this may not be very harmful, it should still be confusing. 394 * We thus reject the case here. 395 */ 396 if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) 397 return (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 398 399 if (rt != NULL) 400 *retifp = if_get(rt->rt_ifidx); 401 402 return (0); 403 } 404 405 int 406 in6_selecthlim(struct inpcb *in6p) 407 { 408 if (in6p && in6p->inp_hops >= 0) 409 return (in6p->inp_hops); 410 411 return (ip6_defhlim); 412 } 413 414 /* 415 * generate kernel-internal form (scopeid embedded into s6_addr16[1]). 416 * If the address scope of is link-local, embed the interface index in the 417 * address. The routine determines our precedence 418 * between advanced API scope/interface specification and basic API 419 * specification. 420 * 421 * this function should be nuked in the future, when we get rid of 422 * embedded scopeid thing. 423 * 424 * XXX actually, it is over-specification to return ifp against sin6_scope_id. 425 * there can be multiple interfaces that belong to a particular scope zone 426 * (in specification, we have 1:N mapping between a scope zone and interfaces). 427 * we may want to change the function to return something other than ifp. 428 */ 429 int 430 in6_embedscope(struct in6_addr *in6, const struct sockaddr_in6 *sin6, 431 struct inpcb *in6p) 432 { 433 struct ifnet *ifp = NULL; 434 u_int32_t scopeid; 435 436 *in6 = sin6->sin6_addr; 437 scopeid = sin6->sin6_scope_id; 438 439 /* 440 * don't try to read sin6->sin6_addr beyond here, since the caller may 441 * ask us to overwrite existing sockaddr_in6 442 */ 443 444 if (IN6_IS_SCOPE_EMBED(in6)) { 445 struct in6_pktinfo *pi; 446 447 /* 448 * KAME assumption: link id == interface id 449 */ 450 451 if (in6p && in6p->inp_outputopts6 && 452 (pi = in6p->inp_outputopts6->ip6po_pktinfo) && 453 pi->ipi6_ifindex) { 454 ifp = if_get(pi->ipi6_ifindex); 455 if (ifp == NULL) 456 return ENXIO; /* XXX EINVAL? */ 457 in6->s6_addr16[1] = htons(pi->ipi6_ifindex); 458 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) && 459 in6p->inp_moptions6 && 460 (ifp = if_get(in6p->inp_moptions6->im6o_ifidx))) { 461 in6->s6_addr16[1] = htons(ifp->if_index); 462 } else if (scopeid) { 463 ifp = if_get(scopeid); 464 if (ifp == NULL) 465 return ENXIO; /* XXX EINVAL? */ 466 /*XXX assignment to 16bit from 32bit variable */ 467 in6->s6_addr16[1] = htons(scopeid & 0xffff); 468 } 469 if_put(ifp); 470 } 471 472 return 0; 473 } 474 475 /* 476 * generate standard sockaddr_in6 from embedded form. 477 * touches sin6_addr and sin6_scope_id only. 478 * 479 * this function should be nuked in the future, when we get rid of 480 * embedded scopeid thing. 481 */ 482 void 483 in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6) 484 { 485 u_int32_t scopeid; 486 487 sin6->sin6_addr = *in6; 488 489 /* 490 * don't try to read *in6 beyond here, since the caller may 491 * ask us to overwrite existing sockaddr_in6 492 */ 493 494 sin6->sin6_scope_id = 0; 495 if (IN6_IS_SCOPE_EMBED(in6)) { 496 /* 497 * KAME assumption: link id == interface id 498 */ 499 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]); 500 if (scopeid) { 501 sin6->sin6_addr.s6_addr16[1] = 0; 502 sin6->sin6_scope_id = scopeid; 503 } 504 } 505 } 506 507 /* 508 * just clear the embedded scope identifer. 509 */ 510 void 511 in6_clearscope(struct in6_addr *addr) 512 { 513 if (IN6_IS_SCOPE_EMBED(addr)) 514 addr->s6_addr16[1] = 0; 515 } 516