in6_src.c revision 1.23
1/* $OpenBSD: in6_src.c,v 1.23 2008/11/23 13:30:59 claudio 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 89static int selectroute(struct sockaddr_in6 *, struct ip6_pktopts *, 90 struct ip6_moptions *, struct route_in6 *, struct ifnet **, 91 struct rtentry **, int); 92 93/* 94 * Return an IPv6 address, which is the most appropriate for a given 95 * destination and user specified options. 96 * If necessary, this function lookups the routing table and returns 97 * an entry to the caller for later use. 98 */ 99struct in6_addr * 100in6_selectsrc(dstsock, opts, mopts, ro, laddr, errorp) 101 struct sockaddr_in6 *dstsock; 102 struct ip6_pktopts *opts; 103 struct ip6_moptions *mopts; 104 struct route_in6 *ro; 105 struct in6_addr *laddr; 106 int *errorp; 107{ 108 struct in6_addr *dst; 109 struct in6_ifaddr *ia6 = 0; 110 struct in6_pktinfo *pi = NULL; 111 112 dst = &dstsock->sin6_addr; 113 *errorp = 0; 114 115 /* 116 * If the source address is explicitly specified by the caller, 117 * use it. 118 */ 119 if (opts && (pi = opts->ip6po_pktinfo) && 120 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) 121 return (&pi->ipi6_addr); 122 123 /* 124 * If the source address is not specified but the socket(if any) 125 * is already bound, use the bound address. 126 */ 127 if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) 128 return (laddr); 129 130 /* 131 * If the caller doesn't specify the source address but 132 * the outgoing interface, use an address associated with 133 * the interface. 134 */ 135 if (pi && pi->ipi6_ifindex) { 136 /* XXX boundary check is assumed to be already done. */ 137 ia6 = in6_ifawithscope(ifindex2ifnet[pi->ipi6_ifindex], 138 dst); 139 if (ia6 == 0) { 140 *errorp = EADDRNOTAVAIL; 141 return (0); 142 } 143 return (&satosin6(&ia6->ia_addr)->sin6_addr); 144 } 145 146 /* 147 * If the destination address is a link-local unicast address or 148 * a link/interface-local multicast address, and if the outgoing 149 * interface is specified by the sin6_scope_id filed, use an address 150 * associated with the interface. 151 * XXX: We're now trying to define more specific semantics of 152 * sin6_scope_id field, so this part will be rewritten in 153 * the near future. 154 */ 155 if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) || 156 IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) { 157 /* 158 * I'm not sure if boundary check for scope_id is done 159 * somewhere... 160 */ 161 if (dstsock->sin6_scope_id < 0 || 162 if_indexlim <= dstsock->sin6_scope_id || 163 !ifindex2ifnet[dstsock->sin6_scope_id]) { 164 *errorp = ENXIO; /* XXX: better error? */ 165 return (0); 166 } 167 ia6 = in6_ifawithscope(ifindex2ifnet[dstsock->sin6_scope_id], 168 dst); 169 if (ia6 == 0) { 170 *errorp = EADDRNOTAVAIL; 171 return (0); 172 } 173 return (&satosin6(&ia6->ia_addr)->sin6_addr); 174 } 175 176 /* 177 * If the destination address is a multicast address and 178 * the outgoing interface for the address is specified 179 * by the caller, use an address associated with the interface. 180 * Even if the outgoing interface is not specified, we also 181 * choose a loopback interface as the outgoing interface. 182 */ 183 if (IN6_IS_ADDR_MULTICAST(dst)) { 184 struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL; 185 186 if (!ifp && dstsock->sin6_scope_id) 187 ifp = ifindex2ifnet[htons(dstsock->sin6_scope_id)]; 188 189 if (ifp) { 190 ia6 = in6_ifawithscope(ifp, dst); 191 if (ia6 == 0) { 192 *errorp = EADDRNOTAVAIL; 193 return (0); 194 } 195 return (&satosin6(&ia6->ia_addr)->sin6_addr); 196 } 197 } 198 199 /* 200 * If the next hop address for the packet is specified 201 * by caller, use an address associated with the route 202 * to the next hop. 203 */ 204 { 205 struct sockaddr_in6 *sin6_next; 206 struct rtentry *rt; 207 208 if (opts && opts->ip6po_nexthop) { 209 sin6_next = satosin6(opts->ip6po_nexthop); 210 rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL); 211 if (rt) { 212 ia6 = in6_ifawithscope(rt->rt_ifp, dst); 213 if (ia6 == 0) 214 ia6 = ifatoia6(rt->rt_ifa); 215 } 216 if (ia6 == 0) { 217 *errorp = EADDRNOTAVAIL; 218 return (0); 219 } 220 return (&satosin6(&ia6->ia_addr)->sin6_addr); 221 } 222 } 223 224 /* 225 * If route is known or can be allocated now, 226 * our src addr is taken from the i/f, else punt. 227 */ 228 if (ro) { 229 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 230 !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr, dst))) { 231 RTFREE(ro->ro_rt); 232 ro->ro_rt = (struct rtentry *)0; 233 } 234 if (ro->ro_rt == (struct rtentry *)0 || 235 ro->ro_rt->rt_ifp == (struct ifnet *)0) { 236 struct sockaddr_in6 *sa6; 237 238 /* No route yet, so try to acquire one */ 239 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 240 sa6 = (struct sockaddr_in6 *)&ro->ro_dst; 241 sa6->sin6_family = AF_INET6; 242 sa6->sin6_len = sizeof(struct sockaddr_in6); 243 sa6->sin6_addr = *dst; 244 sa6->sin6_scope_id = dstsock->sin6_scope_id; 245 if (IN6_IS_ADDR_MULTICAST(dst)) { 246 ro->ro_rt = rtalloc1(&((struct route *)ro) 247 ->ro_dst, 0, 0); 248 } else { 249 rtalloc_mpath((struct route *)ro, NULL, 0); 250 } 251 } 252 253 /* 254 * in_pcbconnect() checks out IFF_LOOPBACK to skip using 255 * the address. But we don't know why it does so. 256 * It is necessary to ensure the scope even for lo0 257 * so doesn't check out IFF_LOOPBACK. 258 */ 259 260 if (ro->ro_rt) { 261 ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst); 262 if (ia6 == 0) /* xxx scope error ?*/ 263 ia6 = ifatoia6(ro->ro_rt->rt_ifa); 264 } 265#if 0 266 /* 267 * xxx The followings are necessary? (kazu) 268 * I don't think so. 269 * It's for SO_DONTROUTE option in IPv4.(jinmei) 270 */ 271 if (ia6 == 0) { 272 struct sockaddr_in6 sin6 = {sizeof(sin6), AF_INET6, 0}; 273 274 sin6->sin6_addr = *dst; 275 276 ia6 = ifatoia6(ifa_ifwithdstaddr(sin6tosa(&sin6))); 277 if (ia6 == 0) 278 ia6 = ifatoia6(ifa_ifwithnet(sin6tosa(&sin6))); 279 if (ia6 == 0) 280 return (0); 281 return (&satosin6(&ia6->ia_addr)->sin6_addr); 282 } 283#endif /* 0 */ 284 if (ia6 == 0) { 285 *errorp = EHOSTUNREACH; /* no route */ 286 return (0); 287 } 288 return (&satosin6(&ia6->ia_addr)->sin6_addr); 289 } 290 291 *errorp = EADDRNOTAVAIL; 292 return (0); 293} 294 295static int 296selectroute(dstsock, opts, mopts, ro, retifp, retrt, norouteok) 297 struct sockaddr_in6 *dstsock; 298 struct ip6_pktopts *opts; 299 struct ip6_moptions *mopts; 300 struct route_in6 *ro; 301 struct ifnet **retifp; 302 struct rtentry **retrt; 303 int norouteok; 304{ 305 int error = 0; 306 struct ifnet *ifp = NULL; 307 struct rtentry *rt = NULL; 308 struct sockaddr_in6 *sin6_next; 309 struct in6_pktinfo *pi = NULL; 310 struct in6_addr *dst; 311 312 dst = &dstsock->sin6_addr; 313 314#if 0 315 if (dstsock->sin6_addr.s6_addr32[0] == 0 && 316 dstsock->sin6_addr.s6_addr32[1] == 0 && 317 !IN6_IS_ADDR_LOOPBACK(&dstsock->sin6_addr)) { 318 printf("in6_selectroute: strange destination %s\n", 319 ip6_sprintf(&dstsock->sin6_addr)); 320 } else { 321 printf("in6_selectroute: destination = %s%%%d\n", 322 ip6_sprintf(&dstsock->sin6_addr), 323 dstsock->sin6_scope_id); /* for debug */ 324 } 325#endif 326 327 /* If the caller specify the outgoing interface explicitly, use it. */ 328 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 329 /* XXX boundary check is assumed to be already done. */ 330 ifp = ifindex2ifnet[pi->ipi6_ifindex]; 331 if (ifp != NULL && 332 (norouteok || retrt == NULL || 333 IN6_IS_ADDR_MULTICAST(dst))) { 334 /* 335 * we do not have to check or get the route for 336 * multicast. 337 */ 338 goto done; 339 } else 340 goto getroute; 341 } 342 343 /* 344 * If the destination address is a multicast address and the outgoing 345 * interface for the address is specified by the caller, use it. 346 */ 347 if (IN6_IS_ADDR_MULTICAST(dst) && 348 mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) { 349 goto done; /* we do not need a route for multicast. */ 350 } 351 352 getroute: 353 /* 354 * If the next hop address for the packet is specified by the caller, 355 * use it as the gateway. 356 */ 357 if (opts && opts->ip6po_nexthop) { 358 struct route_in6 *ron; 359 360 sin6_next = satosin6(opts->ip6po_nexthop); 361 362 /* at this moment, we only support AF_INET6 next hops */ 363 if (sin6_next->sin6_family != AF_INET6) { 364 error = EAFNOSUPPORT; /* or should we proceed? */ 365 goto done; 366 } 367 368 /* 369 * If the next hop is an IPv6 address, then the node identified 370 * by that address must be a neighbor of the sending host. 371 */ 372 ron = &opts->ip6po_nextroute; 373 if ((ron->ro_rt && 374 (ron->ro_rt->rt_flags & (RTF_UP | RTF_GATEWAY)) != 375 RTF_UP) || 376 !IN6_ARE_ADDR_EQUAL(&satosin6(&ron->ro_dst)->sin6_addr, 377 &sin6_next->sin6_addr)) { 378 if (ron->ro_rt) { 379 RTFREE(ron->ro_rt); 380 ron->ro_rt = NULL; 381 } 382 *satosin6(&ron->ro_dst) = *sin6_next; 383 } 384 if (ron->ro_rt == NULL) { 385 rtalloc((struct route *)ron); /* multi path case? */ 386 if (ron->ro_rt == NULL || 387 (ron->ro_rt->rt_flags & RTF_GATEWAY)) { 388 if (ron->ro_rt) { 389 RTFREE(ron->ro_rt); 390 ron->ro_rt = NULL; 391 } 392 error = EHOSTUNREACH; 393 goto done; 394 } 395 } 396 if (!nd6_is_addr_neighbor(sin6_next, ron->ro_rt->rt_ifp)) { 397 RTFREE(ron->ro_rt); 398 ron->ro_rt = NULL; 399 error = EHOSTUNREACH; 400 goto done; 401 } 402 rt = ron->ro_rt; 403 ifp = rt->rt_ifp; 404 405 /* 406 * When cloning is required, try to allocate a route to the 407 * destination so that the caller can store path MTU 408 * information. 409 */ 410 goto done; 411 } 412 413 /* 414 * Use a cached route if it exists and is valid, else try to allocate 415 * a new one. Note that we should check the address family of the 416 * cached destination, in case of sharing the cache with IPv4. 417 */ 418 if (ro) { 419 if (ro->ro_rt && 420 (!(ro->ro_rt->rt_flags & RTF_UP) || 421 ((struct sockaddr *)(&ro->ro_dst))->sa_family != AF_INET6 || 422 !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr, 423 dst))) { 424 RTFREE(ro->ro_rt); 425 ro->ro_rt = (struct rtentry *)NULL; 426 } 427 if (ro->ro_rt == (struct rtentry *)NULL) { 428 struct sockaddr_in6 *sa6; 429 430 /* No route yet, so try to acquire one */ 431 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 432 sa6 = (struct sockaddr_in6 *)&ro->ro_dst; 433 *sa6 = *dstsock; 434 sa6->sin6_scope_id = 0; 435 rtalloc_mpath((struct route *)ro, NULL, 0); 436 } 437 438 /* 439 * do not care about the result if we have the nexthop 440 * explicitly specified. 441 */ 442 if (opts && opts->ip6po_nexthop) 443 goto done; 444 445 if (ro->ro_rt) { 446 ifp = ro->ro_rt->rt_ifp; 447 448 if (ifp == NULL) { /* can this really happen? */ 449 RTFREE(ro->ro_rt); 450 ro->ro_rt = NULL; 451 } 452 } 453 if (ro->ro_rt == NULL) 454 error = EHOSTUNREACH; 455 rt = ro->ro_rt; 456 457 /* 458 * Check if the outgoing interface conflicts with 459 * the interface specified by ipi6_ifindex (if specified). 460 * Note that loopback interface is always okay. 461 * (this may happen when we are sending a packet to one of 462 * our own addresses.) 463 */ 464 if (opts && opts->ip6po_pktinfo && 465 opts->ip6po_pktinfo->ipi6_ifindex) { 466 if (!(ifp->if_flags & IFF_LOOPBACK) && 467 ifp->if_index != 468 opts->ip6po_pktinfo->ipi6_ifindex) { 469 error = EHOSTUNREACH; 470 goto done; 471 } 472 } 473 } 474 475 done: 476 if (ifp == NULL && rt == NULL) { 477 /* 478 * This can happen if the caller did not pass a cached route 479 * nor any other hints. We treat this case an error. 480 */ 481 error = EHOSTUNREACH; 482 } 483 if (error == EHOSTUNREACH) 484 ip6stat.ip6s_noroute++; 485 486 if (retifp != NULL) 487 *retifp = ifp; 488 if (retrt != NULL) 489 *retrt = rt; /* rt may be NULL */ 490 491 return (error); 492} 493 494int 495in6_selectroute(dstsock, opts, mopts, ro, retifp, retrt) 496 struct sockaddr_in6 *dstsock; 497 struct ip6_pktopts *opts; 498 struct ip6_moptions *mopts; 499 struct route_in6 *ro; 500 struct ifnet **retifp; 501 struct rtentry **retrt; 502{ 503 504 return (selectroute(dstsock, opts, mopts, ro, retifp, retrt, 0)); 505} 506 507/* 508 * Default hop limit selection. The precedence is as follows: 509 * 1. Hoplimit value specified via ioctl. 510 * 2. (If the outgoing interface is detected) the current 511 * hop limit of the interface specified by router advertisement. 512 * 3. The system default hoplimit. 513*/ 514#define in6pcb inpcb 515#define in6p_hops inp_hops 516int 517in6_selecthlim(in6p, ifp) 518 struct in6pcb *in6p; 519 struct ifnet *ifp; 520{ 521 if (in6p && in6p->in6p_hops >= 0) 522 return (in6p->in6p_hops); 523 else if (ifp) 524 return (ND_IFINFO(ifp)->chlim); 525 else 526 return (ip6_defhlim); 527} 528#undef in6pcb 529#undef in6p_hops 530 531/* 532 * generate kernel-internal form (scopeid embedded into s6_addr16[1]). 533 * If the address scope of is link-local, embed the interface index in the 534 * address. The routine determines our precedence 535 * between advanced API scope/interface specification and basic API 536 * specification. 537 * 538 * this function should be nuked in the future, when we get rid of 539 * embedded scopeid thing. 540 * 541 * XXX actually, it is over-specification to return ifp against sin6_scope_id. 542 * there can be multiple interfaces that belong to a particular scope zone 543 * (in specification, we have 1:N mapping between a scope zone and interfaces). 544 * we may want to change the function to return something other than ifp. 545 */ 546int 547in6_embedscope(in6, sin6, in6p, ifpp) 548 struct in6_addr *in6; 549 const struct sockaddr_in6 *sin6; 550 struct inpcb *in6p; 551#define in6p_outputopts inp_outputopts6 552#define in6p_moptions inp_moptions6 553 struct ifnet **ifpp; 554{ 555 struct ifnet *ifp = NULL; 556 u_int32_t scopeid; 557 558 *in6 = sin6->sin6_addr; 559 scopeid = sin6->sin6_scope_id; 560 if (ifpp) 561 *ifpp = NULL; 562 563 /* 564 * don't try to read sin6->sin6_addr beyond here, since the caller may 565 * ask us to overwrite existing sockaddr_in6 566 */ 567 568 if (IN6_IS_SCOPE_EMBED(in6)) { 569 struct in6_pktinfo *pi; 570 571 /* 572 * KAME assumption: link id == interface id 573 */ 574 575 if (in6p && in6p->in6p_outputopts && 576 (pi = in6p->in6p_outputopts->ip6po_pktinfo) && 577 pi->ipi6_ifindex) { 578 ifp = ifindex2ifnet[pi->ipi6_ifindex]; 579 in6->s6_addr16[1] = htons(pi->ipi6_ifindex); 580 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) && 581 in6p->in6p_moptions && 582 in6p->in6p_moptions->im6o_multicast_ifp) { 583 ifp = in6p->in6p_moptions->im6o_multicast_ifp; 584 in6->s6_addr16[1] = htons(ifp->if_index); 585 } else if (scopeid) { 586 /* boundary check */ 587 if (scopeid < 0 || if_indexlim <= scopeid || 588 !ifindex2ifnet[scopeid]) 589 return ENXIO; /* XXX EINVAL? */ 590 ifp = ifindex2ifnet[scopeid]; 591 /*XXX assignment to 16bit from 32bit variable */ 592 in6->s6_addr16[1] = htons(scopeid & 0xffff); 593 } 594 595 if (ifpp) 596 *ifpp = ifp; 597 } 598 599 return 0; 600} 601#undef in6p_outputopts 602#undef in6p_moptions 603 604/* 605 * generate standard sockaddr_in6 from embedded form. 606 * touches sin6_addr and sin6_scope_id only. 607 * 608 * this function should be nuked in the future, when we get rid of 609 * embedded scopeid thing. 610 */ 611int 612in6_recoverscope(sin6, in6, ifp) 613 struct sockaddr_in6 *sin6; 614 const struct in6_addr *in6; 615 struct ifnet *ifp; 616{ 617 u_int32_t scopeid; 618 619 sin6->sin6_addr = *in6; 620 621 /* 622 * don't try to read *in6 beyond here, since the caller may 623 * ask us to overwrite existing sockaddr_in6 624 */ 625 626 sin6->sin6_scope_id = 0; 627 if (IN6_IS_SCOPE_EMBED(in6)) { 628 /* 629 * KAME assumption: link id == interface id 630 */ 631 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]); 632 if (scopeid) { 633 /* sanity check */ 634 if (scopeid < 0 || if_indexlim <= scopeid || 635 !ifindex2ifnet[scopeid]) 636 return ENXIO; 637 if (ifp && ifp->if_index != scopeid) 638 return ENXIO; 639 sin6->sin6_addr.s6_addr16[1] = 0; 640 sin6->sin6_scope_id = scopeid; 641 } 642 } 643 644 return 0; 645} 646 647/* 648 * just clear the embedded scope identifer. 649 */ 650void 651in6_clearscope(addr) 652 struct in6_addr *addr; 653{ 654 if (IN6_IS_SCOPE_EMBED(addr)) 655 addr->s6_addr16[1] = 0; 656} 657