1 /* $OpenBSD: in6_src.c,v 1.15 2003/06/02 23:28:15 millert 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/malloc.h> 67 #include <sys/mbuf.h> 68 #include <sys/protosw.h> 69 #include <sys/socket.h> 70 #include <sys/socketvar.h> 71 #include <sys/ioctl.h> 72 #include <sys/errno.h> 73 #include <sys/time.h> 74 #include <sys/proc.h> 75 76 #include <net/if.h> 77 #include <net/route.h> 78 79 #include <netinet/in.h> 80 #include <netinet/in_var.h> 81 #include <netinet/in_systm.h> 82 #include <netinet/ip.h> 83 #include <netinet/in_pcb.h> 84 #include <netinet6/in6_var.h> 85 #include <netinet/ip6.h> 86 #include <netinet6/ip6_var.h> 87 #include <netinet6/nd6.h> 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 struct in6_addr * 96 in6_selectsrc(dstsock, opts, mopts, ro, laddr, errorp) 97 struct sockaddr_in6 *dstsock; 98 struct ip6_pktopts *opts; 99 struct ip6_moptions *mopts; 100 struct route_in6 *ro; 101 struct in6_addr *laddr; 102 int *errorp; 103 { 104 struct in6_addr *dst; 105 struct in6_ifaddr *ia6 = 0; 106 struct in6_pktinfo *pi = NULL; 107 108 dst = &dstsock->sin6_addr; 109 *errorp = 0; 110 111 /* 112 * If the source address is explicitly specified by the caller, 113 * use it. 114 */ 115 if (opts && (pi = opts->ip6po_pktinfo) && 116 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) 117 return (&pi->ipi6_addr); 118 119 /* 120 * If the source address is not specified but the socket(if any) 121 * is already bound, use the bound address. 122 */ 123 if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) 124 return (laddr); 125 126 /* 127 * If the caller doesn't specify the source address but 128 * the outgoing interface, use an address associated with 129 * the interface. 130 */ 131 if (pi && pi->ipi6_ifindex) { 132 /* XXX boundary check is assumed to be already done. */ 133 ia6 = in6_ifawithscope(ifindex2ifnet[pi->ipi6_ifindex], 134 dst); 135 if (ia6 == 0) { 136 *errorp = EADDRNOTAVAIL; 137 return (0); 138 } 139 return (&satosin6(&ia6->ia_addr)->sin6_addr); 140 } 141 142 /* 143 * If the destination address is a link-local unicast address or 144 * a multicast address, and if the outgoing interface is specified 145 * by the sin6_scope_id filed, use an address associated with the 146 * interface. 147 * XXX: We're now trying to define more specific semantics of 148 * sin6_scope_id field, so this part will be rewritten in 149 * the near future. 150 */ 151 if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MULTICAST(dst)) && 152 dstsock->sin6_scope_id) { 153 /* 154 * I'm not sure if boundary check for scope_id is done 155 * somewhere... 156 */ 157 if (dstsock->sin6_scope_id < 0 || 158 if_index < dstsock->sin6_scope_id) { 159 *errorp = ENXIO; /* XXX: better error? */ 160 return (0); 161 } 162 ia6 = in6_ifawithscope(ifindex2ifnet[dstsock->sin6_scope_id], 163 dst); 164 if (ia6 == 0) { 165 *errorp = EADDRNOTAVAIL; 166 return (0); 167 } 168 return (&satosin6(&ia6->ia_addr)->sin6_addr); 169 } 170 171 /* 172 * If the destination address is a multicast address and 173 * the outgoing interface for the address is specified 174 * by the caller, use an address associated with the interface. 175 * There is a sanity check here; if the destination has node-local 176 * scope, the outgoing interfacde should be a loopback address. 177 * Even if the outgoing interface is not specified, we also 178 * choose a loopback interface as the outgoing interface. 179 */ 180 if (IN6_IS_ADDR_MULTICAST(dst)) { 181 struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL; 182 183 if (ifp == NULL && IN6_IS_ADDR_MC_NODELOCAL(dst)) { 184 ifp = lo0ifp; 185 } 186 187 if (ifp) { 188 ia6 = in6_ifawithscope(ifp, dst); 189 if (ia6 == 0) { 190 *errorp = EADDRNOTAVAIL; 191 return (0); 192 } 193 return (&satosin6(&ia6->ia_addr)->sin6_addr); 194 } 195 } 196 197 /* 198 * If the next hop address for the packet is specified 199 * by caller, use an address associated with the route 200 * to the next hop. 201 */ 202 { 203 struct sockaddr_in6 *sin6_next; 204 struct rtentry *rt; 205 206 if (opts && opts->ip6po_nexthop) { 207 sin6_next = satosin6(opts->ip6po_nexthop); 208 rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL); 209 if (rt) { 210 ia6 = in6_ifawithscope(rt->rt_ifp, dst); 211 if (ia6 == 0) 212 ia6 = ifatoia6(rt->rt_ifa); 213 } 214 if (ia6 == 0) { 215 *errorp = EADDRNOTAVAIL; 216 return (0); 217 } 218 return (&satosin6(&ia6->ia_addr)->sin6_addr); 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 (ro->ro_rt && 228 !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr, dst)) { 229 RTFREE(ro->ro_rt); 230 ro->ro_rt = (struct rtentry *)0; 231 } 232 if (ro->ro_rt == (struct rtentry *)0 || 233 ro->ro_rt->rt_ifp == (struct ifnet *)0) { 234 struct sockaddr_in6 *sa6; 235 236 /* No route yet, so try to acquire one */ 237 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 238 sa6 = (struct sockaddr_in6 *)&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 = rtalloc1(&((struct route *)ro) 245 ->ro_dst, 0); 246 } else { 247 rtalloc((struct route *)ro); 248 } 249 } 250 251 /* 252 * in_pcbconnect() checks out IFF_LOOPBACK to skip using 253 * the address. But we don't know why it does so. 254 * It is necessary to ensure the scope even for lo0 255 * so doesn't check out IFF_LOOPBACK. 256 */ 257 258 if (ro->ro_rt) { 259 ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst); 260 if (ia6 == 0) /* xxx scope error ?*/ 261 ia6 = ifatoia6(ro->ro_rt->rt_ifa); 262 } 263 #if 0 264 /* 265 * xxx The followings are necessary? (kazu) 266 * I don't think so. 267 * It's for SO_DONTROUTE option in IPv4.(jinmei) 268 */ 269 if (ia6 == 0) { 270 struct sockaddr_in6 sin6 = {sizeof(sin6), AF_INET6, 0}; 271 272 sin6->sin6_addr = *dst; 273 274 ia6 = ifatoia6(ifa_ifwithdstaddr(sin6tosa(&sin6))); 275 if (ia6 == 0) 276 ia6 = ifatoia6(ifa_ifwithnet(sin6tosa(&sin6))); 277 if (ia6 == 0) 278 return (0); 279 return (&satosin6(&ia6->ia_addr)->sin6_addr); 280 } 281 #endif /* 0 */ 282 if (ia6 == 0) { 283 *errorp = EHOSTUNREACH; /* no route */ 284 return (0); 285 } 286 return (&satosin6(&ia6->ia_addr)->sin6_addr); 287 } 288 289 *errorp = EADDRNOTAVAIL; 290 return (0); 291 } 292 293 /* 294 * Default hop limit selection. The precedence is as follows: 295 * 1. Hoplimit value specified via ioctl. 296 * 2. (If the outgoing interface is detected) the current 297 * hop limit of the interface specified by router advertisement. 298 * 3. The system default hoplimit. 299 */ 300 #define in6pcb inpcb 301 #define in6p_hops inp_hops 302 int 303 in6_selecthlim(in6p, ifp) 304 struct in6pcb *in6p; 305 struct ifnet *ifp; 306 { 307 if (in6p && in6p->in6p_hops >= 0) 308 return (in6p->in6p_hops); 309 else if (ifp) 310 return (ND_IFINFO(ifp)->chlim); 311 else 312 return (ip6_defhlim); 313 } 314 #undef in6pcb 315 #undef in6p_hops 316 317 /* 318 * generate kernel-internal form (scopeid embedded into s6_addr16[1]). 319 * If the address scope of is link-local, embed the interface index in the 320 * address. The routine determines our precedence 321 * between advanced API scope/interface specification and basic API 322 * specification. 323 * 324 * this function should be nuked in the future, when we get rid of 325 * embedded scopeid thing. 326 * 327 * XXX actually, it is over-specification to return ifp against sin6_scope_id. 328 * there can be multiple interfaces that belong to a particular scope zone 329 * (in specification, we have 1:N mapping between a scope zone and interfaces). 330 * we may want to change the function to return something other than ifp. 331 */ 332 int 333 in6_embedscope(in6, sin6, in6p, ifpp) 334 struct in6_addr *in6; 335 const struct sockaddr_in6 *sin6; 336 struct inpcb *in6p; 337 #define in6p_outputopts inp_outputopts6 338 #define in6p_moptions inp_moptions6 339 struct ifnet **ifpp; 340 { 341 struct ifnet *ifp = NULL; 342 u_int32_t scopeid; 343 344 *in6 = sin6->sin6_addr; 345 scopeid = sin6->sin6_scope_id; 346 if (ifpp) 347 *ifpp = NULL; 348 349 /* 350 * don't try to read sin6->sin6_addr beyond here, since the caller may 351 * ask us to overwrite existing sockaddr_in6 352 */ 353 354 if (IN6_IS_SCOPE_LINKLOCAL(in6)) { 355 struct in6_pktinfo *pi; 356 357 /* 358 * KAME assumption: link id == interface id 359 */ 360 361 if (in6p && in6p->in6p_outputopts && 362 (pi = in6p->in6p_outputopts->ip6po_pktinfo) && 363 pi->ipi6_ifindex) { 364 ifp = ifindex2ifnet[pi->ipi6_ifindex]; 365 in6->s6_addr16[1] = htons(pi->ipi6_ifindex); 366 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) && 367 in6p->in6p_moptions && 368 in6p->in6p_moptions->im6o_multicast_ifp) { 369 ifp = in6p->in6p_moptions->im6o_multicast_ifp; 370 in6->s6_addr16[1] = htons(ifp->if_index); 371 } else if (scopeid) { 372 /* boundary check */ 373 if (scopeid < 0 || if_index < scopeid) 374 return ENXIO; /* XXX EINVAL? */ 375 ifp = ifindex2ifnet[scopeid]; 376 /*XXX assignment to 16bit from 32bit variable */ 377 in6->s6_addr16[1] = htons(scopeid & 0xffff); 378 } 379 380 if (ifpp) 381 *ifpp = ifp; 382 } 383 384 return 0; 385 } 386 #undef in6p_outputopts 387 #undef in6p_moptions 388 389 /* 390 * generate standard sockaddr_in6 from embedded form. 391 * touches sin6_addr and sin6_scope_id only. 392 * 393 * this function should be nuked in the future, when we get rid of 394 * embedded scopeid thing. 395 */ 396 int 397 in6_recoverscope(sin6, in6, ifp) 398 struct sockaddr_in6 *sin6; 399 const struct in6_addr *in6; 400 struct ifnet *ifp; 401 { 402 u_int32_t scopeid; 403 404 sin6->sin6_addr = *in6; 405 406 /* 407 * don't try to read *in6 beyond here, since the caller may 408 * ask us to overwrite existing sockaddr_in6 409 */ 410 411 sin6->sin6_scope_id = 0; 412 if (IN6_IS_SCOPE_LINKLOCAL(in6)) { 413 /* 414 * KAME assumption: link id == interface id 415 */ 416 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]); 417 if (scopeid) { 418 /* sanity check */ 419 if (scopeid < 0 || if_index < scopeid) 420 return ENXIO; 421 if (ifp && ifp->if_index != scopeid) 422 return ENXIO; 423 sin6->sin6_addr.s6_addr16[1] = 0; 424 sin6->sin6_scope_id = scopeid; 425 } 426 } 427 428 return 0; 429 } 430 431 /* 432 * just clear the embedded scope identifer. 433 */ 434 void 435 in6_clearscope(addr) 436 struct in6_addr *addr; 437 { 438 if (IN6_IS_SCOPE_LINKLOCAL(addr)) 439 addr->s6_addr16[1] = 0; 440 } 441