in6_src.c revision 1.70
1/* $OpenBSD: in6_src.c,v 1.70 2015/10/25 14:43:06 florian 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 86int 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 */ 95int 96in6_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 if (IN6_IS_ADDR_MULTICAST(dst)) { 244 ro->ro_rt = rtalloc(sin6tosa(&ro->ro_dst), 245 RT_REPORT|RT_RESOLVE, ro->ro_tableid); 246 } else { 247 ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst), 248 NULL, ro->ro_tableid); 249 } 250 } 251 252 /* 253 * in_pcbconnect() checks out IFF_LOOPBACK to skip using 254 * the address. But we don't know why it does so. 255 * It is necessary to ensure the scope even for lo0 256 * so doesn't check out IFF_LOOPBACK. 257 */ 258 259 if (ro->ro_rt) { 260 ifp = if_get(ro->ro_rt->rt_ifidx); 261 if (ifp != NULL) { 262 ia6 = in6_ifawithscope(ifp, dst, rtableid); 263 if_put(ifp); 264 } 265 if (ia6 == NULL) /* xxx scope error ?*/ 266 ia6 = ifatoia6(ro->ro_rt->rt_ifa); 267 } 268 if (ia6 == NULL) 269 return (EHOSTUNREACH); /* no route */ 270 271 *in6src = &ia6->ia_addr.sin6_addr; 272 return (0); 273 } 274 275 return (EADDRNOTAVAIL); 276} 277 278struct rtentry * 279in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 280 struct route_in6 *ro, unsigned int rtableid) 281{ 282 struct in6_addr *dst; 283 284 dst = &dstsock->sin6_addr; 285 286 /* 287 * Use a cached route if it exists and is valid, else try to allocate 288 * a new one. Note that we should check the address family of the 289 * cached destination, in case of sharing the cache with IPv4. 290 */ 291 if (ro) { 292 if (!rtisvalid(ro->ro_rt) || 293 sin6tosa(&ro->ro_dst)->sa_family != AF_INET6 || 294 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) { 295 rtfree(ro->ro_rt); 296 ro->ro_rt = NULL; 297 } 298 if (ro->ro_rt == NULL) { 299 struct sockaddr_in6 *sa6; 300 301 /* No route yet, so try to acquire one */ 302 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 303 ro->ro_tableid = rtableid; 304 sa6 = &ro->ro_dst; 305 *sa6 = *dstsock; 306 sa6->sin6_scope_id = 0; 307 ro->ro_tableid = rtableid; 308 ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst), 309 NULL, ro->ro_tableid); 310 } 311 312 /* 313 * Check if the outgoing interface conflicts with 314 * the interface specified by ipi6_ifindex (if specified). 315 * Note that loopback interface is always okay. 316 * (this may happen when we are sending a packet to one of 317 * our own addresses.) 318 */ 319 if (opts && opts->ip6po_pktinfo && 320 opts->ip6po_pktinfo->ipi6_ifindex) { 321 if (ro->ro_rt != NULL && 322 !ISSET(ro->ro_rt->rt_flags, RTF_LOCAL) && 323 ro->ro_rt->rt_ifidx != 324 opts->ip6po_pktinfo->ipi6_ifindex) { 325 return (NULL); 326 } 327 } 328 329 return (ro->ro_rt); 330 } 331 332 return (NULL); 333} 334 335int 336in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 337 struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp, 338 u_int rtableid) 339{ 340 struct rtentry *rt = NULL; 341 struct in6_pktinfo *pi = NULL; 342 343 /* If the caller specify the outgoing interface explicitly, use it. */ 344 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 345 *retifp = if_get(pi->ipi6_ifindex); 346 if (*retifp != NULL) 347 return (0); 348 } 349 350 /* 351 * If the destination address is a multicast address and the outgoing 352 * interface for the address is specified by the caller, use it. 353 */ 354 if (IN6_IS_ADDR_MULTICAST(&dstsock->sin6_addr) && 355 mopts != NULL && (*retifp = if_get(mopts->im6o_ifidx)) != NULL) 356 return (0); 357 358 rt = in6_selectroute(dstsock, opts, ro, rtableid); 359 if (rt == NULL) 360 return (EHOSTUNREACH); 361 362 /* 363 * do not use a rejected or black hole route. 364 * XXX: this check should be done in the L2 output routine. 365 * However, if we skipped this check here, we'd see the following 366 * scenario: 367 * - install a rejected route for a scoped address prefix 368 * (like fe80::/10) 369 * - send a packet to a destination that matches the scoped prefix, 370 * with ambiguity about the scope zone. 371 * - pick the outgoing interface from the route, and disambiguate the 372 * scope zone with the interface. 373 * - ip6_output() would try to get another route with the "new" 374 * destination, which may be valid. 375 * - we'd see no error on output. 376 * Although this may not be very harmful, it should still be confusing. 377 * We thus reject the case here. 378 */ 379 if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) 380 return (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 381 382 if (rt != NULL) 383 *retifp = if_get(rt->rt_ifidx); 384 385 return (0); 386} 387 388/* 389 * Default hop limit selection. The precedence is as follows: 390 * 1. Hoplimit value specified via ioctl. 391 * 2. (If the outgoing interface is detected) the current 392 * hop limit of the interface specified by router advertisement. 393 * 3. The system default hoplimit. 394*/ 395int 396in6_selecthlim(struct inpcb *in6p) 397{ 398 if (in6p && in6p->inp_hops >= 0) 399 return (in6p->inp_hops); 400 401 return (ip6_defhlim); 402} 403 404/* 405 * generate kernel-internal form (scopeid embedded into s6_addr16[1]). 406 * If the address scope of is link-local, embed the interface index in the 407 * address. The routine determines our precedence 408 * between advanced API scope/interface specification and basic API 409 * specification. 410 * 411 * this function should be nuked in the future, when we get rid of 412 * embedded scopeid thing. 413 * 414 * XXX actually, it is over-specification to return ifp against sin6_scope_id. 415 * there can be multiple interfaces that belong to a particular scope zone 416 * (in specification, we have 1:N mapping between a scope zone and interfaces). 417 * we may want to change the function to return something other than ifp. 418 */ 419int 420in6_embedscope(struct in6_addr *in6, const struct sockaddr_in6 *sin6, 421 struct inpcb *in6p) 422{ 423 struct ifnet *ifp = NULL; 424 u_int32_t scopeid; 425 426 *in6 = sin6->sin6_addr; 427 scopeid = sin6->sin6_scope_id; 428 429 /* 430 * don't try to read sin6->sin6_addr beyond here, since the caller may 431 * ask us to overwrite existing sockaddr_in6 432 */ 433 434 if (IN6_IS_SCOPE_EMBED(in6)) { 435 struct in6_pktinfo *pi; 436 437 /* 438 * KAME assumption: link id == interface id 439 */ 440 441 if (in6p && in6p->inp_outputopts6 && 442 (pi = in6p->inp_outputopts6->ip6po_pktinfo) && 443 pi->ipi6_ifindex) { 444 ifp = if_get(pi->ipi6_ifindex); 445 if (ifp == NULL) 446 return ENXIO; /* XXX EINVAL? */ 447 in6->s6_addr16[1] = htons(pi->ipi6_ifindex); 448 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) && 449 in6p->inp_moptions6 && 450 (ifp = if_get(in6p->inp_moptions6->im6o_ifidx))) { 451 in6->s6_addr16[1] = htons(ifp->if_index); 452 } else if (scopeid) { 453 ifp = if_get(scopeid); 454 if (ifp == NULL) 455 return ENXIO; /* XXX EINVAL? */ 456 /*XXX assignment to 16bit from 32bit variable */ 457 in6->s6_addr16[1] = htons(scopeid & 0xffff); 458 } 459 if_put(ifp); 460 } 461 462 return 0; 463} 464 465/* 466 * generate standard sockaddr_in6 from embedded form. 467 * touches sin6_addr and sin6_scope_id only. 468 * 469 * this function should be nuked in the future, when we get rid of 470 * embedded scopeid thing. 471 */ 472void 473in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6) 474{ 475 u_int32_t scopeid; 476 477 sin6->sin6_addr = *in6; 478 479 /* 480 * don't try to read *in6 beyond here, since the caller may 481 * ask us to overwrite existing sockaddr_in6 482 */ 483 484 sin6->sin6_scope_id = 0; 485 if (IN6_IS_SCOPE_EMBED(in6)) { 486 /* 487 * KAME assumption: link id == interface id 488 */ 489 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]); 490 if (scopeid) { 491 sin6->sin6_addr.s6_addr16[1] = 0; 492 sin6->sin6_scope_id = scopeid; 493 } 494 } 495} 496 497/* 498 * just clear the embedded scope identifer. 499 */ 500void 501in6_clearscope(struct in6_addr *addr) 502{ 503 if (IN6_IS_SCOPE_EMBED(addr)) 504 addr->s6_addr16[1] = 0; 505} 506