bsd/netinet6/in6_src.c

   1 /*
   2  * Copyright (c) 2008 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 /*      $FreeBSD: src/sys/netinet6/in6_src.c,v 1.1.2.2 2001/07/03 11:01:52 ume Exp $    */
  30 /*      $KAME: in6_src.c,v 1.37 2001/03/29 05:34:31 itojun Exp $        */
  31
  32 /*
  33  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  34  * All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  * 1. Redistributions of source code must retain the above copyright
  40  *    notice, this list of conditions and the following disclaimer.
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in the
  43  *    documentation and/or other materials provided with the distribution.
  44  * 3. Neither the name of the project nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  */
  60
  61 /*
  62  * Copyright (c) 1982, 1986, 1991, 1993
  63  *      The Regents of the University of California.  All rights reserved.
  64  *
  65  * Redistribution and use in source and binary forms, with or without
  66  * modification, are permitted provided that the following conditions
  67  * are met:
  68  * 1. Redistributions of source code must retain the above copyright
  69  *    notice, this list of conditions and the following disclaimer.
  70  * 2. Redistributions in binary form must reproduce the above copyright
  71  *    notice, this list of conditions and the following disclaimer in the
  72  *    documentation and/or other materials provided with the distribution.
  73  * 3. All advertising materials mentioning features or use of this software
  74  *    must display the following acknowledgement:
  75  *      This product includes software developed by the University of
  76  *      California, Berkeley and its contributors.
  77  * 4. Neither the name of the University nor the names of its contributors
  78  *    may be used to endorse or promote products derived from this software
  79  *    without specific prior written permission.
  80  *
  81  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  82  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  83  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  84  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  85  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  86  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  87  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  88  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  89  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  90  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  91  * SUCH DAMAGE.
  92  *
  93  *      @(#)in_pcb.c    8.2 (Berkeley) 1/4/94
  94  */
  95
  96
  97 #include <sys/param.h>
  98 #include <sys/systm.h>
  99 #include <sys/malloc.h>
 100 #include <sys/mbuf.h>
 101 #include <sys/protosw.h>
 102 #include <sys/socket.h>
 103 #include <sys/socketvar.h>
 104 #include <sys/errno.h>
 105 #include <sys/time.h>
 106 #include <sys/proc.h>
 107 #include <kern/lock.h>
 108
 109 #include <net/if.h>
 110 #include <net/route.h>
 111
 112 #include <netinet/in.h>
 113 #include <netinet/in_var.h>
 114 #include <netinet/in_systm.h>
 115 #include <netinet/ip.h>
 116 #include <netinet/in_pcb.h>
 117 #include <netinet6/in6_var.h>
 118 #include <netinet/ip6.h>
 119 #include <netinet6/in6_pcb.h>
 120 #include <netinet6/ip6_var.h>
 121 #include <netinet6/nd6.h>
 122 #if ENABLE_DEFAULT_SCOPE
 123 #include <netinet6/scope6_var.h>
 124 #endif
 125
 126 #include <net/net_osdep.h>
 127
 128 #include "loop.h"
 129
 130 /*
 131  * Return an IPv6 address, which is the most appropriate for a given
 132  * destination and user specified options.
 133  * If necessary, this function lookups the routing table and returns
 134  * an entry to the caller for later use.
 135  */
 136 struct in6_addr *
 137 in6_selectsrc(
 138         struct sockaddr_in6 *dstsock,
 139         struct ip6_pktopts *opts,
 140         struct ip6_moptions *mopts,
 141         struct route_in6 *ro,
 142         struct in6_addr *laddr,
 143         struct in6_addr *src_storage,
 144         int *errorp)
 145 {
 146         struct in6_addr *dst;
 147         struct in6_ifaddr *ia6 = 0;
 148         struct in6_pktinfo *pi = NULL;
 149
 150         dst = &dstsock->sin6_addr;
 151         *errorp = 0;
 152
 153         /*
 154          * If the source address is explicitly specified by the caller,
 155          * use it.
 156          */
 157         if (opts && (pi = opts->ip6po_pktinfo) &&
 158             !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr))
 159                 return(&pi->ipi6_addr);
 160
 161         /*
 162          * If the source address is not specified but the socket(if any)
 163          * is already bound, use the bound address.
 164          */
 165         if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr))
 166                 return(laddr);
 167
 168         /*
 169          * If the caller doesn't specify the source address but
 170          * the outgoing interface, use an address associated with
 171          * the interface.
 172          */
 173         if (pi && pi->ipi6_ifindex) {
 174                 ifnet_t out_ifp = NULL;
 175                 ifnet_head_lock_shared();
 176                 if (pi->ipi6_ifindex > if_index) {
 177                         ifnet_head_done();
 178                         *errorp = EADDRNOTAVAIL;
 179                         return(0);
 180                 } else {
 181                         out_ifp = ifindex2ifnet[pi->ipi6_ifindex];
 182                 }
 183                 ifnet_head_done();
 184
 185                 /* XXX boundary check is assumed to be already done. */
 186                 ia6 = in6_ifawithscope(out_ifp, dst);
 187                 if (ia6 == 0) {
 188                         *errorp = EADDRNOTAVAIL;
 189                         return(0);
 190                 }
 191                 *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 192                 ifafree(&ia6->ia_ifa);
 193                 return src_storage;
 194         }
 195
 196         /*
 197          * If the destination address is a link-local unicast address or
 198          * a multicast address, and if the outgoing interface is specified
 199          * by the sin6_scope_id filed, use an address associated with the
 200          * interface.
 201          * XXX: We're now trying to define more specific semantics of
 202          *      sin6_scope_id field, so this part will be rewritten in
 203          *      the near future.
 204          */
 205         if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MULTICAST(dst)) &&
 206             dstsock->sin6_scope_id) {
 207                 /*
 208                  * I'm not sure if boundary check for scope_id is done
 209                  * somewhere...
 210                  *
 211                  * Since sin6_scope_id is unsigned, we only need to check against if_index.
 212                  */
 213                 ifnet_t out_ifp = NULL;
 214                 ifnet_head_lock_shared();
 215                 if (if_index < dstsock->sin6_scope_id) {
 216                         *errorp = ENXIO; /* XXX: better error? */
 217                         ifnet_head_done();
 218                         return(0);
 219                 } else {
 220                         out_ifp = ifindex2ifnet[dstsock->sin6_scope_id];
 221                 }
 222                 ifnet_head_done();
 223
 224                 ia6 = in6_ifawithscope(out_ifp, dst);
 225                 if (ia6 == 0) {
 226                         *errorp = EADDRNOTAVAIL;
 227                         return(0);
 228                 }
 229                 *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 230                 ifafree(&ia6->ia_ifa);
 231                 return src_storage;
 232         }
 233
 234         /*
 235          * If the destination address is a multicast address and
 236          * the outgoing interface for the address is specified
 237          * by the caller, use an address associated with the interface.
 238          * There is a sanity check here; if the destination has node-local
 239          * scope, the outgoing interfacde should be a loopback address.
 240          * Even if the outgoing interface is not specified, we also
 241          * choose a loopback interface as the outgoing interface.
 242          */
 243         if (IN6_IS_ADDR_MULTICAST(dst)) {
 244                 struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL;
 245
 246                 if (ifp == NULL && IN6_IS_ADDR_MC_NODELOCAL(dst)) {
 247                         ifp = lo_ifp;
 248                 }
 249
 250                 if (ifp) {
 251                         ia6 = in6_ifawithscope(ifp, dst);
 252                         if (ia6 == 0) {
 253                                 *errorp = EADDRNOTAVAIL;
 254                                 return(0);
 255                         }
 256                         *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 257                         ifafree(&ia6->ia_ifa);
 258                         return src_storage;
 259                 }
 260         }
 261
 262         /*
 263          * If the next hop address for the packet is specified
 264          * by caller, use an address associated with the route
 265          * to the next hop.
 266          */
 267         {
 268                 struct sockaddr_in6 *sin6_next;
 269                 struct rtentry *rt;
 270
 271                 if (opts && opts->ip6po_nexthop) {
 272                         sin6_next = satosin6(opts->ip6po_nexthop);
 273                         rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL, 0);
 274                         if (rt != NULL) {
 275                                 RT_LOCK_ASSERT_HELD(rt);
 276                                 ia6 = in6_ifawithscope(rt->rt_ifp, dst);
 277                                 if (ia6 == 0) {
 278                                         ia6 = ifatoia6(rt->rt_ifa);
 279                                         if (ia6 != NULL)
 280                                                 ifaref(&ia6->ia_ifa);
 281                                 }
 282                         }
 283                         if (ia6 == 0) {
 284                                 *errorp = EADDRNOTAVAIL;
 285                                 if (rt != NULL) {
 286                                         RT_REMREF_LOCKED(rt);
 287                                         RT_UNLOCK(rt);
 288                                 }
 289                                 return(0);
 290                         }
 291                         *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 292                         ifafree(&ia6->ia_ifa);
 293                         RT_REMREF_LOCKED(rt);
 294                         RT_UNLOCK(rt);
 295                         return src_storage;
 296                 }
 297         }
 298
 299         /*
 300          * If route is known or can be allocated now,
 301          * our src addr is taken from the i/f, else punt.
 302          */
 303         if (ro) {
 304                 if (ro->ro_rt != NULL)
 305                         RT_LOCK(ro->ro_rt);
 306                 if (ro->ro_rt != NULL &&
 307                     (!(ro->ro_rt->rt_flags & RTF_UP) ||
 308                      satosin6(&ro->ro_dst)->sin6_family != AF_INET6 ||
 309                      ro->ro_rt->generation_id != route_generation ||
 310                      !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr,
 311                                          dst))) {
 312                         RT_UNLOCK(ro->ro_rt);
 313                         rtfree(ro->ro_rt);
 314                         ro->ro_rt = NULL;
 315                 }
 316                 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp == NULL) {
 317                         struct sockaddr_in6 *sa6;
 318
 319                         if (ro->ro_rt != NULL)
 320                                 RT_UNLOCK(ro->ro_rt);
 321                         /* No route yet, so try to acquire one */
 322                         bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
 323                         sa6 = (struct sockaddr_in6 *)&ro->ro_dst;
 324                         sa6->sin6_family = AF_INET6;
 325                         sa6->sin6_len = sizeof(struct sockaddr_in6);
 326                         sa6->sin6_addr = *dst;
 327 #if SCOPEDROUTING
 328                         sa6->sin6_scope_id = dstsock->sin6_scope_id;
 329 #endif
 330                         if (IN6_IS_ADDR_MULTICAST(dst)) {
 331                                 ro->ro_rt = rtalloc1(
 332                                     &((struct route *)ro)->ro_dst, 0, 0);
 333                         } else {
 334                                 rtalloc_ign((struct route *)ro, 0);
 335                         }
 336                         if (ro->ro_rt != NULL)
 337                                 RT_LOCK(ro->ro_rt);
 338                 }
 339
 340                 /*
 341                  * in_pcbconnect() checks out IFF_LOOPBACK to skip using
 342                  * the address. But we don't know why it does so.
 343                  * It is necessary to ensure the scope even for lo0
 344                  * so doesn't check out IFF_LOOPBACK.
 345                  */
 346                 if (ro->ro_rt != NULL) {
 347                         RT_LOCK_ASSERT_HELD(ro->ro_rt);
 348                         ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst);
 349                         if (ia6 == 0) {
 350                                 ia6 = ifatoia6(ro->ro_rt->rt_ifa);
 351                                 if (ia6)
 352                                         ifaref(&ia6->ia_ifa);
 353                         }
 354                         RT_UNLOCK(ro->ro_rt);
 355                 }
 356 #if 0
 357                 /*
 358                  * xxx The followings are necessary? (kazu)
 359                  * I don't think so.
 360                  * It's for SO_DONTROUTE option in IPv4.(jinmei)
 361                  */
 362                 if (ia6 == 0) {
 363                         struct sockaddr_in6 sin6 = {sizeof(sin6), AF_INET6, 0};
 364
 365                         sin6->sin6_addr = *dst;
 366
 367                         ia6 = ifatoia6(ifa_ifwithdstaddr(sin6tosa(&sin6)));
 368                         if (ia6 == 0)
 369                                 ia6 = ifatoia6(ifa_ifwithnet(sin6tosa(&sin6)));
 370                         if (ia6 == 0)
 371                                 return(0);
 372                         *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 373                         ifafree(&ia6->ia_ifa);
 374                         return src_storage;
 375                 }
 376 #endif /* 0 */
 377                 if (ia6 == 0) {
 378                         *errorp = EHOSTUNREACH; /* no route */
 379                         return(0);
 380                 }
 381                 *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 382                 ifafree(&ia6->ia_ifa);
 383                 return src_storage;
 384         }
 385
 386         *errorp = EADDRNOTAVAIL;
 387         return(0);
 388 }
 389
 390 /*
 391  * Default hop limit selection. The precedence is as follows:
 392  * 1. Hoplimit value specified via ioctl.
 393  * 2. (If the outgoing interface is detected) the current
 394  *     hop limit of the interface specified by router advertisement.
 395  * 3. The system default hoplimit.
 396 */
 397 int
 398 in6_selecthlim(
 399         struct in6pcb *in6p,
 400         struct ifnet *ifp)
 401 {
 402         if (in6p && in6p->in6p_hops >= 0) {
 403                 return(in6p->in6p_hops);
 404         } else {
 405                 lck_rw_lock_shared(nd_if_rwlock);
 406                 if (ifp && ifp->if_index < nd_ifinfo_indexlim) {
 407                         u_int8_t chlim = nd_ifinfo[ifp->if_index].chlim;
 408                         lck_rw_done(nd_if_rwlock);
 409                         return (chlim);
 410                 } else {
 411                         lck_rw_done(nd_if_rwlock);
 412                         return(ip6_defhlim);
 413                 }
 414         }
 415 }
 416
 417 /*
 418  * XXX: this is borrowed from in6_pcbbind(). If possible, we should
 419  * share this function by all *bsd*...
 420  */
 421 int
 422 in6_pcbsetport(
 423         __unused struct in6_addr *laddr,
 424         struct inpcb *inp,
 425         struct proc *p,
 426         int locked)
 427 {
 428         struct socket *so = inp->inp_socket;
 429         u_int16_t lport = 0, first, last, *lastport;
 430         int count, error = 0, wild = 0;
 431         struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
 432         if (!locked) { /* Make sure we don't run into a deadlock: 4052373 */
 433                 if (!lck_rw_try_lock_exclusive(pcbinfo->mtx)) {
 434                         socket_unlock(inp->inp_socket, 0);
 435                         lck_rw_lock_exclusive(pcbinfo->mtx);
 436                         socket_lock(inp->inp_socket, 0);
 437                 }
 438         }
 439
 440         /* XXX: this is redundant when called from in6_pcbbind */
 441         if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0)
 442                 wild = INPLOOKUP_WILDCARD;
 443
 444         inp->inp_flags |= INP_ANONPORT;
 445
 446         if (inp->inp_flags & INP_HIGHPORT) {
 447                 first = ipport_hifirstauto;     /* sysctl */
 448                 last  = ipport_hilastauto;
 449                 lastport = &pcbinfo->lasthi;
 450         } else if (inp->inp_flags & INP_LOWPORT) {
 451                 if ((error = proc_suser(p)) != 0) {
 452                         if (!locked)
 453                                 lck_rw_done(pcbinfo->mtx);
 454                         return error;
 455                 }
 456                 first = ipport_lowfirstauto;    /* 1023 */
 457                 last  = ipport_lowlastauto;     /* 600 */
 458                 lastport = &pcbinfo->lastlow;
 459         } else {
 460                 first = ipport_firstauto;       /* sysctl */
 461                 last  = ipport_lastauto;
 462                 lastport = &pcbinfo->lastport;
 463         }
 464         /*
 465          * Simple check to ensure all ports are not used up causing
 466          * a deadlock here.
 467          *
 468          * We split the two cases (up and down) so that the direction
 469          * is not being tested on each round of the loop.
 470          */
 471         if (first > last) {
 472                 /*
 473                  * counting down
 474                  */
 475                 count = first - last;
 476
 477                 do {
 478                         if (count-- < 0) {      /* completely used? */
 479                                 /*
 480                                  * Undo any address bind that may have
 481                                  * occurred above.
 482                                  */
 483                                 inp->in6p_laddr = in6addr_any;
 484                                 if (!locked)
 485                                         lck_rw_done(pcbinfo->mtx);
 486                                 return (EAGAIN);
 487                         }
 488                         --*lastport;
 489                         if (*lastport > first || *lastport < last)
 490                                 *lastport = first;
 491                         lport = htons(*lastport);
 492                 } while (in6_pcblookup_local(pcbinfo,
 493                                              &inp->in6p_laddr, lport, wild));
 494         } else {
 495                 /*
 496                          * counting up
 497                          */
 498                 count = last - first;
 499
 500                 do {
 501                         if (count-- < 0) {      /* completely used? */
 502                                 /*
 503                                  * Undo any address bind that may have
 504                                  * occurred above.
 505                                  */
 506                                 inp->in6p_laddr = in6addr_any;
 507                                 if (!locked)
 508                                         lck_rw_done(pcbinfo->mtx);
 509                                 return (EAGAIN);
 510                         }
 511                         ++*lastport;
 512                         if (*lastport < first || *lastport > last)
 513                                 *lastport = first;
 514                         lport = htons(*lastport);
 515                 } while (in6_pcblookup_local(pcbinfo,
 516                                              &inp->in6p_laddr, lport, wild));
 517         }
 518
 519         inp->inp_lport = lport;
 520         if (in_pcbinshash(inp, 1) != 0) {
 521                 inp->in6p_laddr = in6addr_any;
 522                 inp->inp_lport = 0;
 523                 if (!locked)
 524                         lck_rw_done(pcbinfo->mtx);
 525                 return (EAGAIN);
 526         }
 527
 528         if (!locked)
 529                 lck_rw_done(pcbinfo->mtx);
 530         return(0);
 531 }
 532
 533 /*
 534  * generate kernel-internal form (scopeid embedded into s6_addr16[1]).
 535  * If the address scope of is link-local, embed the interface index in the
 536  * address.  The routine determines our precedence
 537  * between advanced API scope/interface specification and basic API
 538  * specification.
 539  *
 540  * this function should be nuked in the future, when we get rid of
 541  * embedded scopeid thing.
 542  *
 543  * XXX actually, it is over-specification to return ifp against sin6_scope_id.
 544  * there can be multiple interfaces that belong to a particular scope zone
 545  * (in specification, we have 1:N mapping between a scope zone and interfaces).
 546  * we may want to change the function to return something other than ifp.
 547  */
 548 int
 549 in6_embedscope(
 550         struct in6_addr *in6,
 551         const struct sockaddr_in6 *sin6,
 552 #ifdef HAVE_NRL_INPCB
 553         struct inpcb *in6p,
 554 #define in6p_outputopts inp_outputopts6
 555 #define in6p_moptions   inp_moptions6
 556 #else
 557         struct in6pcb *in6p,
 558 #endif
 559         struct ifnet **ifpp)
 560 {
 561         struct ifnet *ifp = NULL;
 562         u_int32_t scopeid;
 563
 564         *in6 = sin6->sin6_addr;
 565         scopeid = sin6->sin6_scope_id;
 566         if (ifpp)
 567                 *ifpp = NULL;
 568
 569         /*
 570          * don't try to read sin6->sin6_addr beyond here, since the caller may
 571          * ask us to overwrite existing sockaddr_in6
 572          */
 573
 574 #ifdef ENABLE_DEFAULT_SCOPE
 575         if (scopeid == 0)
 576                 scopeid = scope6_addr2default(in6);
 577 #endif
 578
 579         if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
 580                 struct in6_pktinfo *pi;
 581
 582                 /*
 583                  * KAME assumption: link id == interface id
 584                  */
 585
 586                 ifnet_head_lock_shared();
 587                 if (in6p && in6p->in6p_outputopts &&
 588                     (pi = in6p->in6p_outputopts->ip6po_pktinfo) &&
 589                     pi->ipi6_ifindex) {
 590                         ifp = ifindex2ifnet[pi->ipi6_ifindex];
 591                         in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
 592                 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
 593                            in6p->in6p_moptions &&
 594                            in6p->in6p_moptions->im6o_multicast_ifp) {
 595                         ifp = in6p->in6p_moptions->im6o_multicast_ifp;
 596                         in6->s6_addr16[1] = htons(ifp->if_index);
 597                 } else if (scopeid) {
 598                         /*
 599                          * Since scopeid is unsigned, we only have to check it
 600                          * against if_index
 601                          */
 602                         if (if_index < scopeid) {
 603                                 ifnet_head_done();
 604                                 return ENXIO;  /* XXX EINVAL? */
 605
 606                         }
 607                         ifp = ifindex2ifnet[scopeid];
 608                         /*XXX assignment to 16bit from 32bit variable */
 609                         in6->s6_addr16[1] = htons(scopeid & 0xffff);
 610                 }
 611                 ifnet_head_done();
 612
 613                 if (ifpp)
 614                         *ifpp = ifp;
 615         }
 616
 617         return 0;
 618 }
 619 #if HAVE_NRL_INPCB
 620 #undef in6p_outputopts
 621 #undef in6p_moptions
 622 #endif
 623
 624 /*
 625  * generate standard sockaddr_in6 from embedded form.
 626  * touches sin6_addr and sin6_scope_id only.
 627  *
 628  * this function should be nuked in the future, when we get rid of
 629  * embedded scopeid thing.
 630  */
 631 int
 632 in6_recoverscope(
 633         struct sockaddr_in6 *sin6,
 634         const struct in6_addr *in6,
 635         struct ifnet *ifp)
 636 {
 637         u_int32_t scopeid;
 638
 639         sin6->sin6_addr = *in6;
 640
 641         /*
 642          * don't try to read *in6 beyond here, since the caller may
 643          * ask us to overwrite existing sockaddr_in6
 644          */
 645
 646         sin6->sin6_scope_id = 0;
 647         if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
 648                 /*
 649                  * KAME assumption: link id == interface id
 650                  */
 651                 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]);
 652                 if (scopeid) {
 653                         /*
 654                          * sanity check
 655                          *
 656                          * Since scopeid is unsigned, we only have to check it
 657                          * against if_index
 658                          */
 659                         if (if_index < scopeid)
 660                                 return ENXIO;
 661                         if (ifp && ifp->if_index != scopeid)
 662                                 return ENXIO;
 663                         sin6->sin6_addr.s6_addr16[1] = 0;
 664                         sin6->sin6_scope_id = scopeid;
 665                 }
 666         }
 667
 668         return 0;
 669 }
 670
 671 /*
 672  * just clear the embedded scope identifer.
 673  * XXX: currently used for bsdi4 only as a supplement function.
 674  */
 675 void
 676 in6_clearscope(addr)
 677         struct in6_addr *addr;
 678 {
 679         if (IN6_IS_SCOPE_LINKLOCAL(addr))
 680                 addr->s6_addr16[1] = 0;
 681 }