1 /* $OpenBSD: in6_src.c,v 1.16 2003/12/10 03:30:21 itojun 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_indexlim <= dstsock->sin6_scope_id || 159 !ifindex2ifnet[dstsock->sin6_scope_id]) { 160 *errorp = ENXIO; /* XXX: better error? */ 161 return (0); 162 } 163 ia6 = in6_ifawithscope(ifindex2ifnet[dstsock->sin6_scope_id], 164 dst); 165 if (ia6 == 0) { 166 *errorp = EADDRNOTAVAIL; 167 return (0); 168 } 169 return (&satosin6(&ia6->ia_addr)->sin6_addr); 170 } 171 172 /* 173 * If the destination address is a multicast address and 174 * the outgoing interface for the address is specified 175 * by the caller, use an address associated with the interface. 176 * There is a sanity check here; if the destination has node-local 177 * scope, the outgoing interfacde should be a loopback address. 178 * Even if the outgoing interface is not specified, we also 179 * choose a loopback interface as the outgoing interface. 180 */ 181 if (IN6_IS_ADDR_MULTICAST(dst)) { 182 struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL; 183 184 if (ifp == NULL && IN6_IS_ADDR_MC_NODELOCAL(dst)) { 185 ifp = lo0ifp; 186 } 187 188 if (ifp) { 189 ia6 = in6_ifawithscope(ifp, dst); 190 if (ia6 == 0) { 191 *errorp = EADDRNOTAVAIL; 192 return (0); 193 } 194 return (&satosin6(&ia6->ia_addr)->sin6_addr); 195 } 196 } 197 198 /* 199 * If the next hop address for the packet is specified 200 * by caller, use an address associated with the route 201 * to the next hop. 202 */ 203 { 204 struct sockaddr_in6 *sin6_next; 205 struct rtentry *rt; 206 207 if (opts && opts->ip6po_nexthop) { 208 sin6_next = satosin6(opts->ip6po_nexthop); 209 rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL); 210 if (rt) { 211 ia6 = in6_ifawithscope(rt->rt_ifp, dst); 212 if (ia6 == 0) 213 ia6 = ifatoia6(rt->rt_ifa); 214 } 215 if (ia6 == 0) { 216 *errorp = EADDRNOTAVAIL; 217 return (0); 218 } 219 return (&satosin6(&ia6->ia_addr)->sin6_addr); 220 } 221 } 222 223 /* 224 * If route is known or can be allocated now, 225 * our src addr is taken from the i/f, else punt. 226 */ 227 if (ro) { 228 if (ro->ro_rt && 229 !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr, dst)) { 230 RTFREE(ro->ro_rt); 231 ro->ro_rt = (struct rtentry *)0; 232 } 233 if (ro->ro_rt == (struct rtentry *)0 || 234 ro->ro_rt->rt_ifp == (struct ifnet *)0) { 235 struct sockaddr_in6 *sa6; 236 237 /* No route yet, so try to acquire one */ 238 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 239 sa6 = (struct sockaddr_in6 *)&ro->ro_dst; 240 sa6->sin6_family = AF_INET6; 241 sa6->sin6_len = sizeof(struct sockaddr_in6); 242 sa6->sin6_addr = *dst; 243 sa6->sin6_scope_id = dstsock->sin6_scope_id; 244 if (IN6_IS_ADDR_MULTICAST(dst)) { 245 ro->ro_rt = rtalloc1(&((struct route *)ro) 246 ->ro_dst, 0); 247 } else { 248 rtalloc((struct route *)ro); 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 ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst); 261 if (ia6 == 0) /* xxx scope error ?*/ 262 ia6 = ifatoia6(ro->ro_rt->rt_ifa); 263 } 264 #if 0 265 /* 266 * xxx The followings are necessary? (kazu) 267 * I don't think so. 268 * It's for SO_DONTROUTE option in IPv4.(jinmei) 269 */ 270 if (ia6 == 0) { 271 struct sockaddr_in6 sin6 = {sizeof(sin6), AF_INET6, 0}; 272 273 sin6->sin6_addr = *dst; 274 275 ia6 = ifatoia6(ifa_ifwithdstaddr(sin6tosa(&sin6))); 276 if (ia6 == 0) 277 ia6 = ifatoia6(ifa_ifwithnet(sin6tosa(&sin6))); 278 if (ia6 == 0) 279 return (0); 280 return (&satosin6(&ia6->ia_addr)->sin6_addr); 281 } 282 #endif /* 0 */ 283 if (ia6 == 0) { 284 *errorp = EHOSTUNREACH; /* no route */ 285 return (0); 286 } 287 return (&satosin6(&ia6->ia_addr)->sin6_addr); 288 } 289 290 *errorp = EADDRNOTAVAIL; 291 return (0); 292 } 293 294 /* 295 * Default hop limit selection. The precedence is as follows: 296 * 1. Hoplimit value specified via ioctl. 297 * 2. (If the outgoing interface is detected) the current 298 * hop limit of the interface specified by router advertisement. 299 * 3. The system default hoplimit. 300 */ 301 #define in6pcb inpcb 302 #define in6p_hops inp_hops 303 int 304 in6_selecthlim(in6p, ifp) 305 struct in6pcb *in6p; 306 struct ifnet *ifp; 307 { 308 if (in6p && in6p->in6p_hops >= 0) 309 return (in6p->in6p_hops); 310 else if (ifp) 311 return (ND_IFINFO(ifp)->chlim); 312 else 313 return (ip6_defhlim); 314 } 315 #undef in6pcb 316 #undef in6p_hops 317 318 /* 319 * generate kernel-internal form (scopeid embedded into s6_addr16[1]). 320 * If the address scope of is link-local, embed the interface index in the 321 * address. The routine determines our precedence 322 * between advanced API scope/interface specification and basic API 323 * specification. 324 * 325 * this function should be nuked in the future, when we get rid of 326 * embedded scopeid thing. 327 * 328 * XXX actually, it is over-specification to return ifp against sin6_scope_id. 329 * there can be multiple interfaces that belong to a particular scope zone 330 * (in specification, we have 1:N mapping between a scope zone and interfaces). 331 * we may want to change the function to return something other than ifp. 332 */ 333 int 334 in6_embedscope(in6, sin6, in6p, ifpp) 335 struct in6_addr *in6; 336 const struct sockaddr_in6 *sin6; 337 struct inpcb *in6p; 338 #define in6p_outputopts inp_outputopts6 339 #define in6p_moptions inp_moptions6 340 struct ifnet **ifpp; 341 { 342 struct ifnet *ifp = NULL; 343 u_int32_t scopeid; 344 345 *in6 = sin6->sin6_addr; 346 scopeid = sin6->sin6_scope_id; 347 if (ifpp) 348 *ifpp = NULL; 349 350 /* 351 * don't try to read sin6->sin6_addr beyond here, since the caller may 352 * ask us to overwrite existing sockaddr_in6 353 */ 354 355 if (IN6_IS_SCOPE_LINKLOCAL(in6)) { 356 struct in6_pktinfo *pi; 357 358 /* 359 * KAME assumption: link id == interface id 360 */ 361 362 if (in6p && in6p->in6p_outputopts && 363 (pi = in6p->in6p_outputopts->ip6po_pktinfo) && 364 pi->ipi6_ifindex) { 365 ifp = ifindex2ifnet[pi->ipi6_ifindex]; 366 in6->s6_addr16[1] = htons(pi->ipi6_ifindex); 367 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) && 368 in6p->in6p_moptions && 369 in6p->in6p_moptions->im6o_multicast_ifp) { 370 ifp = in6p->in6p_moptions->im6o_multicast_ifp; 371 in6->s6_addr16[1] = htons(ifp->if_index); 372 } else if (scopeid) { 373 /* boundary check */ 374 if (scopeid < 0 || if_indexlim <= scopeid || 375 !ifindex2ifnet[scopeid]) 376 return ENXIO; /* XXX EINVAL? */ 377 ifp = ifindex2ifnet[scopeid]; 378 /*XXX assignment to 16bit from 32bit variable */ 379 in6->s6_addr16[1] = htons(scopeid & 0xffff); 380 } 381 382 if (ifpp) 383 *ifpp = ifp; 384 } 385 386 return 0; 387 } 388 #undef in6p_outputopts 389 #undef in6p_moptions 390 391 /* 392 * generate standard sockaddr_in6 from embedded form. 393 * touches sin6_addr and sin6_scope_id only. 394 * 395 * this function should be nuked in the future, when we get rid of 396 * embedded scopeid thing. 397 */ 398 int 399 in6_recoverscope(sin6, in6, ifp) 400 struct sockaddr_in6 *sin6; 401 const struct in6_addr *in6; 402 struct ifnet *ifp; 403 { 404 u_int32_t scopeid; 405 406 sin6->sin6_addr = *in6; 407 408 /* 409 * don't try to read *in6 beyond here, since the caller may 410 * ask us to overwrite existing sockaddr_in6 411 */ 412 413 sin6->sin6_scope_id = 0; 414 if (IN6_IS_SCOPE_LINKLOCAL(in6)) { 415 /* 416 * KAME assumption: link id == interface id 417 */ 418 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]); 419 if (scopeid) { 420 /* sanity check */ 421 if (scopeid < 0 || if_indexlim <= scopeid || 422 !ifindex2ifnet[scopeid]) 423 return ENXIO; 424 if (ifp && ifp->if_index != scopeid) 425 return ENXIO; 426 sin6->sin6_addr.s6_addr16[1] = 0; 427 sin6->sin6_scope_id = scopeid; 428 } 429 } 430 431 return 0; 432 } 433 434 /* 435 * just clear the embedded scope identifer. 436 */ 437 void 438 in6_clearscope(addr) 439 struct in6_addr *addr; 440 { 441 if (IN6_IS_SCOPE_LINKLOCAL(addr)) 442 addr->s6_addr16[1] = 0; 443 } 444