bsd/netinet6/in6_src.c

   1 /*      $FreeBSD: src/sys/netinet6/in6_src.c,v 1.1.2.2 2001/07/03 11:01:52 ume Exp $    */
   2 /*      $KAME: in6_src.c,v 1.37 2001/03/29 05:34:31 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. All advertising materials mentioning features or use of this software
  46  *    must display the following acknowledgement:
  47  *      This product includes software developed by the University of
  48  *      California, Berkeley and its contributors.
  49  * 4. Neither the name of the University nor the names of its contributors
  50  *    may be used to endorse or promote products derived from this software
  51  *    without specific prior written permission.
  52  *
  53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  63  * SUCH DAMAGE.
  64  *
  65  *      @(#)in_pcb.c    8.2 (Berkeley) 1/4/94
  66  */
  67
  68
  69 #include <sys/param.h>
  70 #include <sys/systm.h>
  71 #include <sys/malloc.h>
  72 #include <sys/mbuf.h>
  73 #include <sys/protosw.h>
  74 #include <sys/socket.h>
  75 #include <sys/socketvar.h>
  76 #include <sys/errno.h>
  77 #include <sys/time.h>
  78 #include <sys/proc.h>
  79 #include <kern/lock.h>
  80
  81 #include <net/if.h>
  82 #include <net/route.h>
  83
  84 #include <netinet/in.h>
  85 #include <netinet/in_var.h>
  86 #include <netinet/in_systm.h>
  87 #include <netinet/ip.h>
  88 #include <netinet/in_pcb.h>
  89 #include <netinet6/in6_var.h>
  90 #include <netinet/ip6.h>
  91 #include <netinet6/in6_pcb.h>
  92 #include <netinet6/ip6_var.h>
  93 #include <netinet6/nd6.h>
  94 #if ENABLE_DEFAULT_SCOPE
  95 #include <netinet6/scope6_var.h>
  96 #endif
  97
  98 #include <net/net_osdep.h>
  99
 100 #include "loop.h"
 101 extern lck_mtx_t *rt_mtx;
 102
 103 /*
 104  * Return an IPv6 address, which is the most appropriate for a given
 105  * destination and user specified options.
 106  * If necessary, this function lookups the routing table and returns
 107  * an entry to the caller for later use.
 108  */
 109 struct in6_addr *
 110 in6_selectsrc(
 111         struct sockaddr_in6 *dstsock,
 112         struct ip6_pktopts *opts,
 113         struct ip6_moptions *mopts,
 114         struct route_in6 *ro,
 115         struct in6_addr *laddr,
 116         struct in6_addr *src_storage,
 117         int *errorp)
 118 {
 119         struct in6_addr *dst;
 120         struct in6_ifaddr *ia6 = 0;
 121         struct in6_pktinfo *pi = NULL;
 122
 123         dst = &dstsock->sin6_addr;
 124         *errorp = 0;
 125
 126         /*
 127          * If the source address is explicitly specified by the caller,
 128          * use it.
 129          */
 130         if (opts && (pi = opts->ip6po_pktinfo) &&
 131             !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr))
 132                 return(&pi->ipi6_addr);
 133
 134         /*
 135          * If the source address is not specified but the socket(if any)
 136          * is already bound, use the bound address.
 137          */
 138         if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr))
 139                 return(laddr);
 140
 141         /*
 142          * If the caller doesn't specify the source address but
 143          * the outgoing interface, use an address associated with
 144          * the interface.
 145          */
 146         if (pi && pi->ipi6_ifindex) {
 147                 /* XXX boundary check is assumed to be already done. */
 148                 ia6 = in6_ifawithscope(ifindex2ifnet[pi->ipi6_ifindex],
 149                                        dst);
 150                 if (ia6 == 0) {
 151                         *errorp = EADDRNOTAVAIL;
 152                         return(0);
 153                 }
 154                 *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 155                 return src_storage;
 156         }
 157
 158         /*
 159          * If the destination address is a link-local unicast address or
 160          * a multicast address, and if the outgoing interface is specified
 161          * by the sin6_scope_id filed, use an address associated with the
 162          * interface.
 163          * XXX: We're now trying to define more specific semantics of
 164          *      sin6_scope_id field, so this part will be rewritten in
 165          *      the near future.
 166          */
 167         if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MULTICAST(dst)) &&
 168             dstsock->sin6_scope_id) {
 169                 /*
 170                  * I'm not sure if boundary check for scope_id is done
 171                  * somewhere...
 172                  */
 173                 if (dstsock->sin6_scope_id < 0 ||
 174                     if_index < dstsock->sin6_scope_id) {
 175                         *errorp = ENXIO; /* XXX: better error? */
 176                         return(0);
 177                 }
 178                 ia6 = in6_ifawithscope(ifindex2ifnet[dstsock->sin6_scope_id],
 179                                        dst);
 180                 if (ia6 == 0) {
 181                         *errorp = EADDRNOTAVAIL;
 182                         return(0);
 183                 }
 184                 *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 185                 return src_storage;
 186         }
 187
 188         /*
 189          * If the destination address is a multicast address and
 190          * the outgoing interface for the address is specified
 191          * by the caller, use an address associated with the interface.
 192          * There is a sanity check here; if the destination has node-local
 193          * scope, the outgoing interfacde should be a loopback address.
 194          * Even if the outgoing interface is not specified, we also
 195          * choose a loopback interface as the outgoing interface.
 196          */
 197         if (IN6_IS_ADDR_MULTICAST(dst)) {
 198                 struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL;
 199
 200                 if (ifp == NULL && IN6_IS_ADDR_MC_NODELOCAL(dst)) {
 201                         ifp = &loif[0];
 202                 }
 203
 204                 if (ifp) {
 205                         ia6 = in6_ifawithscope(ifp, dst);
 206                         if (ia6 == 0) {
 207                                 *errorp = EADDRNOTAVAIL;
 208                                 return(0);
 209                         }
 210                         *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 211                         return src_storage;
 212                 }
 213         }
 214
 215         /*
 216          * If the next hop address for the packet is specified
 217          * by caller, use an address associated with the route
 218          * to the next hop.
 219          */
 220         {
 221                 struct sockaddr_in6 *sin6_next;
 222                 struct rtentry *rt;
 223
 224                 if (opts && opts->ip6po_nexthop) {
 225                         sin6_next = satosin6(opts->ip6po_nexthop);
 226                         rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL, 0);
 227                         if (rt) {
 228                                 ia6 = in6_ifawithscope(rt->rt_ifp, dst);
 229                                 if (ia6 == 0)
 230                                         ia6 = ifatoia6(rt->rt_ifa);
 231                         }
 232                         if (ia6 == 0) {
 233                                 *errorp = EADDRNOTAVAIL;
 234                                 return(0);
 235                         }
 236                         *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 237                         return src_storage;
 238                 }
 239         }
 240
 241         /*
 242          * If route is known or can be allocated now,
 243          * our src addr is taken from the i/f, else punt.
 244          */
 245         if (ro) {
 246                 lck_mtx_lock(rt_mtx);
 247                 if (ro->ro_rt &&
 248                     (!(ro->ro_rt->rt_flags & RTF_UP) ||
 249                      satosin6(&ro->ro_dst)->sin6_family != AF_INET6 ||
 250                      !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr,
 251                                          dst))) {
 252                         rtfree_locked(ro->ro_rt);
 253                         ro->ro_rt = (struct rtentry *)0;
 254                 }
 255                 if (ro->ro_rt == (struct rtentry *)0 ||
 256                     ro->ro_rt->rt_ifp == 0) {
 257                         struct sockaddr_in6 *sa6;
 258
 259                         /* No route yet, so try to acquire one */
 260                         bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
 261                         sa6 = (struct sockaddr_in6 *)&ro->ro_dst;
 262                         sa6->sin6_family = AF_INET6;
 263                         sa6->sin6_len = sizeof(struct sockaddr_in6);
 264                         sa6->sin6_addr = *dst;
 265                         sa6->sin6_scope_id = dstsock->sin6_scope_id;
 266                         if (IN6_IS_ADDR_MULTICAST(dst)) {
 267                                 ro->ro_rt = rtalloc1_locked(&((struct route *)ro)
 268                                                      ->ro_dst, 0, 0UL);
 269                         } else {
 270                                 rtalloc_ign_locked((struct route *)ro, 0UL);
 271                         }
 272                 }
 273                 lck_mtx_unlock(rt_mtx);
 274
 275                 /*
 276                  * in_pcbconnect() checks out IFF_LOOPBACK to skip using
 277                  * the address. But we don't know why it does so.
 278                  * It is necessary to ensure the scope even for lo0
 279                  * so doesn't check out IFF_LOOPBACK.
 280                  */
 281
 282                 if (ro->ro_rt) {
 283                         ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst);
 284                         if (ia6 == 0) {
 285                                 ia6 = ifatoia6(ro->ro_rt->rt_ifa);
 286                                 if (ia6)
 287                                         ifaref(&ia6->ia_ifa);
 288                         }
 289                         else {
 290                                 ifaref(&ia6->ia_ifa);
 291                         }
 292                 }
 293 #if 0
 294                 /*
 295                  * xxx The followings are necessary? (kazu)
 296                  * I don't think so.
 297                  * It's for SO_DONTROUTE option in IPv4.(jinmei)
 298                  */
 299                 if (ia6 == 0) {
 300                         struct sockaddr_in6 sin6 = {sizeof(sin6), AF_INET6, 0};
 301
 302                         sin6->sin6_addr = *dst;
 303
 304                         ia6 = ifatoia6(ifa_ifwithdstaddr(sin6tosa(&sin6)));
 305                         if (ia6 == 0)
 306                                 ia6 = ifatoia6(ifa_ifwithnet(sin6tosa(&sin6)));
 307                         if (ia6 == 0)
 308                                 return(0);
 309                         *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 310                         return src_storage;
 311                 }
 312 #endif /* 0 */
 313                 if (ia6 == 0) {
 314                         *errorp = EHOSTUNREACH; /* no route */
 315                         return(0);
 316                 }
 317                 *src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
 318                 ifafree(&ia6->ia_ifa);
 319                 return src_storage;
 320         }
 321
 322         *errorp = EADDRNOTAVAIL;
 323         return(0);
 324 }
 325
 326 /*
 327  * Default hop limit selection. The precedence is as follows:
 328  * 1. Hoplimit value specified via ioctl.
 329  * 2. (If the outgoing interface is detected) the current
 330  *     hop limit of the interface specified by router advertisement.
 331  * 3. The system default hoplimit.
 332 */
 333 int
 334 in6_selecthlim(
 335         struct in6pcb *in6p,
 336         struct ifnet *ifp)
 337 {
 338         if (in6p && in6p->in6p_hops >= 0)
 339                 return(in6p->in6p_hops);
 340         else if (ifp)
 341                 return(nd_ifinfo[ifp->if_index].chlim);
 342         else
 343                 return(ip6_defhlim);
 344 }
 345
 346 /*
 347  * XXX: this is borrowed from in6_pcbbind(). If possible, we should
 348  * share this function by all *bsd*...
 349  */
 350 int
 351 in6_pcbsetport(laddr, inp, p, locked)
 352         struct in6_addr *laddr;
 353         struct inpcb *inp;
 354         struct proc *p;
 355         int locked;
 356 {
 357         struct socket *so = inp->inp_socket;
 358         u_int16_t lport = 0, first, last, *lastport;
 359         int count, error = 0, wild = 0;
 360         struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
 361         if (!locked) { /* Make sure we don't run into a deadlock: 4052373 */
 362                 if (!lck_rw_try_lock_exclusive(pcbinfo->mtx)) {
 363                         socket_unlock(inp->inp_socket, 0);
 364                         lck_rw_lock_exclusive(pcbinfo->mtx);
 365                         socket_lock(inp->inp_socket, 0);
 366                 }
 367         }
 368
 369         /* XXX: this is redundant when called from in6_pcbbind */
 370         if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0)
 371                 wild = INPLOOKUP_WILDCARD;
 372
 373         inp->inp_flags |= INP_ANONPORT;
 374
 375         if (inp->inp_flags & INP_HIGHPORT) {
 376                 first = ipport_hifirstauto;     /* sysctl */
 377                 last  = ipport_hilastauto;
 378                 lastport = &pcbinfo->lasthi;
 379         } else if (inp->inp_flags & INP_LOWPORT) {
 380                 if (p && (error = proc_suser(p))) {
 381                         if (!locked)
 382                                 lck_rw_done(pcbinfo->mtx);
 383                         return error;
 384                 }
 385                 first = ipport_lowfirstauto;    /* 1023 */
 386                 last  = ipport_lowlastauto;     /* 600 */
 387                 lastport = &pcbinfo->lastlow;
 388         } else {
 389                 first = ipport_firstauto;       /* sysctl */
 390                 last  = ipport_lastauto;
 391                 lastport = &pcbinfo->lastport;
 392         }
 393         /*
 394          * Simple check to ensure all ports are not used up causing
 395          * a deadlock here.
 396          *
 397          * We split the two cases (up and down) so that the direction
 398          * is not being tested on each round of the loop.
 399          */
 400         if (first > last) {
 401                 /*
 402                  * counting down
 403                  */
 404                 count = first - last;
 405
 406                 do {
 407                         if (count-- < 0) {      /* completely used? */
 408                                 /*
 409                                  * Undo any address bind that may have
 410                                  * occurred above.
 411                                  */
 412                                 inp->in6p_laddr = in6addr_any;
 413                                 if (!locked)
 414                                         lck_rw_done(pcbinfo->mtx);
 415                                 return (EAGAIN);
 416                         }
 417                         --*lastport;
 418                         if (*lastport > first || *lastport < last)
 419                                 *lastport = first;
 420                         lport = htons(*lastport);
 421                 } while (in6_pcblookup_local(pcbinfo,
 422                                              &inp->in6p_laddr, lport, wild));
 423         } else {
 424                 /*
 425                          * counting up
 426                          */
 427                 count = last - first;
 428
 429                 do {
 430                         if (count-- < 0) {      /* completely used? */
 431                                 /*
 432                                  * Undo any address bind that may have
 433                                  * occurred above.
 434                                  */
 435                                 inp->in6p_laddr = in6addr_any;
 436                                 if (!locked)
 437                                         lck_rw_done(pcbinfo->mtx);
 438                                 return (EAGAIN);
 439                         }
 440                         ++*lastport;
 441                         if (*lastport < first || *lastport > last)
 442                                 *lastport = first;
 443                         lport = htons(*lastport);
 444                 } while (in6_pcblookup_local(pcbinfo,
 445                                              &inp->in6p_laddr, lport, wild));
 446         }
 447
 448         inp->inp_lport = lport;
 449         if (in_pcbinshash(inp, 1) != 0) {
 450                 inp->in6p_laddr = in6addr_any;
 451                 inp->inp_lport = 0;
 452                 if (!locked)
 453                         lck_rw_done(pcbinfo->mtx);
 454                 return (EAGAIN);
 455         }
 456
 457         if (!locked)
 458                 lck_rw_done(pcbinfo->mtx);
 459         return(0);
 460 }
 461
 462 /*
 463  * generate kernel-internal form (scopeid embedded into s6_addr16[1]).
 464  * If the address scope of is link-local, embed the interface index in the
 465  * address.  The routine determines our precedence
 466  * between advanced API scope/interface specification and basic API
 467  * specification.
 468  *
 469  * this function should be nuked in the future, when we get rid of
 470  * embedded scopeid thing.
 471  *
 472  * XXX actually, it is over-specification to return ifp against sin6_scope_id.
 473  * there can be multiple interfaces that belong to a particular scope zone
 474  * (in specification, we have 1:N mapping between a scope zone and interfaces).
 475  * we may want to change the function to return something other than ifp.
 476  */
 477 int
 478 in6_embedscope(
 479         struct in6_addr *in6,
 480         const struct sockaddr_in6 *sin6,
 481 #ifdef HAVE_NRL_INPCB
 482         struct inpcb *in6p,
 483 #define in6p_outputopts inp_outputopts6
 484 #define in6p_moptions   inp_moptions6
 485 #else
 486         struct in6pcb *in6p,
 487 #endif
 488         struct ifnet **ifpp)
 489 {
 490         struct ifnet *ifp = NULL;
 491         u_int32_t scopeid;
 492
 493         *in6 = sin6->sin6_addr;
 494         scopeid = sin6->sin6_scope_id;
 495         if (ifpp)
 496                 *ifpp = NULL;
 497
 498         /*
 499          * don't try to read sin6->sin6_addr beyond here, since the caller may
 500          * ask us to overwrite existing sockaddr_in6
 501          */
 502
 503 #ifdef ENABLE_DEFAULT_SCOPE
 504         if (scopeid == 0)
 505                 scopeid = scope6_addr2default(in6);
 506 #endif
 507
 508         if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
 509                 struct in6_pktinfo *pi;
 510
 511                 /*
 512                  * KAME assumption: link id == interface id
 513                  */
 514
 515                 if (in6p && in6p->in6p_outputopts &&
 516                     (pi = in6p->in6p_outputopts->ip6po_pktinfo) &&
 517                     pi->ipi6_ifindex) {
 518                         ifp = ifindex2ifnet[pi->ipi6_ifindex];
 519                         in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
 520                 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
 521                            in6p->in6p_moptions &&
 522                            in6p->in6p_moptions->im6o_multicast_ifp) {
 523                         ifp = in6p->in6p_moptions->im6o_multicast_ifp;
 524                         in6->s6_addr16[1] = htons(ifp->if_index);
 525                 } else if (scopeid) {
 526                         /* boundary check */
 527                         if (scopeid < 0 || if_index < scopeid)
 528                                 return ENXIO;  /* XXX EINVAL? */
 529                         ifp = ifindex2ifnet[scopeid];
 530                         /*XXX assignment to 16bit from 32bit variable */
 531                         in6->s6_addr16[1] = htons(scopeid & 0xffff);
 532                 }
 533
 534                 if (ifpp)
 535                         *ifpp = ifp;
 536         }
 537
 538         return 0;
 539 }
 540 #if HAVE_NRL_INPCB
 541 #undef in6p_outputopts
 542 #undef in6p_moptions
 543 #endif
 544
 545 /*
 546  * generate standard sockaddr_in6 from embedded form.
 547  * touches sin6_addr and sin6_scope_id only.
 548  *
 549  * this function should be nuked in the future, when we get rid of
 550  * embedded scopeid thing.
 551  */
 552 int
 553 in6_recoverscope(
 554         struct sockaddr_in6 *sin6,
 555         const struct in6_addr *in6,
 556         struct ifnet *ifp)
 557 {
 558         u_int32_t scopeid;
 559
 560         sin6->sin6_addr = *in6;
 561
 562         /*
 563          * don't try to read *in6 beyond here, since the caller may
 564          * ask us to overwrite existing sockaddr_in6
 565          */
 566
 567         sin6->sin6_scope_id = 0;
 568         if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
 569                 /*
 570                  * KAME assumption: link id == interface id
 571                  */
 572                 scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]);
 573                 if (scopeid) {
 574                         /* sanity check */
 575                         if (scopeid < 0 || if_index < scopeid)
 576                                 return ENXIO;
 577                         if (ifp && ifp->if_index != scopeid)
 578                                 return ENXIO;
 579                         sin6->sin6_addr.s6_addr16[1] = 0;
 580                         sin6->sin6_scope_id = scopeid;
 581                 }
 582         }
 583
 584         return 0;
 585 }
 586
 587 /*
 588  * just clear the embedded scope identifer.
 589  * XXX: currently used for bsdi4 only as a supplement function.
 590  */
 591 void
 592 in6_clearscope(addr)
 593         struct in6_addr *addr;
 594 {
 595         if (IN6_IS_SCOPE_LINKLOCAL(addr))
 596                 addr->s6_addr16[1] = 0;
 597 }