root/netinet6/in6_ifattach.c

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DEFINITIONS

This source file includes following definitions.
  1. get_rand_ifid
  2. get_hw_ifid
  3. get_ifid
  4. in6_ifattach_linklocal
  5. in6_ifattach_loopback
  6. in6_nigroup
  7. in6_ifattach
  8. in6_ifdetach

    1 /*      $OpenBSD: in6_ifattach.c,v 1.45 2007/06/08 09:31:38 henning Exp $       */
    2 /*      $KAME: in6_ifattach.c,v 1.124 2001/07/18 08:32:51 jinmei 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 #include <sys/param.h>
   34 #include <sys/systm.h>
   35 #include <sys/malloc.h>
   36 #include <sys/socket.h>
   37 #include <sys/sockio.h>
   38 #include <sys/kernel.h>
   39 #include <sys/syslog.h>
   40 
   41 #include <crypto/md5.h>
   42 
   43 #include <net/if.h>
   44 #include <net/if_dl.h>
   45 #include <net/if_types.h>
   46 #include <net/route.h>
   47 
   48 #include <netinet/in.h>
   49 #include <netinet/in_var.h>
   50 #include <netinet/if_ether.h>
   51 
   52 #include <netinet/ip6.h>
   53 #include <netinet6/ip6_var.h>
   54 #include <netinet6/in6_ifattach.h>
   55 #include <netinet6/ip6_var.h>
   56 #include <netinet6/nd6.h>
   57 #ifdef MROUTING
   58 #include <netinet6/ip6_mroute.h>
   59 #endif
   60 
   61 unsigned long in6_maxmtu = 0;
   62 
   63 int ip6_auto_linklocal = 1;     /* enable by default */
   64 
   65 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
   66 static int get_hw_ifid(struct ifnet *, struct in6_addr *);
   67 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
   68 static int in6_ifattach_loopback(struct ifnet *);
   69 
   70 #define EUI64_GBIT      0x01
   71 #define EUI64_UBIT      0x02
   72 #define EUI64_TO_IFID(in6)      do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
   73 #define EUI64_GROUP(in6)        ((in6)->s6_addr[8] & EUI64_GBIT)
   74 #define EUI64_INDIVIDUAL(in6)   (!EUI64_GROUP(in6))
   75 #define EUI64_LOCAL(in6)        ((in6)->s6_addr[8] & EUI64_UBIT)
   76 #define EUI64_UNIVERSAL(in6)    (!EUI64_LOCAL(in6))
   77 
   78 #define IFID_LOCAL(in6)         (!EUI64_LOCAL(in6))
   79 #define IFID_UNIVERSAL(in6)     (!EUI64_UNIVERSAL(in6))
   80 
   81 /*
   82  * Generate a last-resort interface identifier, when the machine has no
   83  * IEEE802/EUI64 address sources.
   84  * The goal here is to get an interface identifier that is
   85  * (1) random enough and (2) does not change across reboot.
   86  * We currently use MD5(hostname) for it.
   87  */
   88 static int
   89 get_rand_ifid(ifp, in6)
   90         struct ifnet *ifp;
   91         struct in6_addr *in6;   /* upper 64bits are preserved */
   92 {
   93         MD5_CTX ctxt;
   94         u_int8_t digest[16];
   95 
   96 #if 0
   97         /* we need at least several letters as seed for ifid */
   98         if (hostnamelen < 3)
   99                 return -1;
  100 #endif
  101 
  102         /* generate 8 bytes of pseudo-random value. */
  103         bzero(&ctxt, sizeof(ctxt));
  104         MD5Init(&ctxt);
  105         MD5Update(&ctxt, hostname, hostnamelen);
  106         MD5Final(digest, &ctxt);
  107 
  108         /* assumes sizeof(digest) > sizeof(ifid) */
  109         bcopy(digest, &in6->s6_addr[8], 8);
  110 
  111         /* make sure to set "u" bit to local, and "g" bit to individual. */
  112         in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */
  113         in6->s6_addr[8] |= EUI64_UBIT;  /* u bit to "local" */
  114 
  115         /* convert EUI64 into IPv6 interface identifier */
  116         EUI64_TO_IFID(in6);
  117 
  118         return 0;
  119 }
  120 
  121 /*
  122  * Get interface identifier for the specified interface.
  123  * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
  124  */
  125 static int
  126 get_hw_ifid(ifp, in6)
  127         struct ifnet *ifp;
  128         struct in6_addr *in6;   /* upper 64bits are preserved */
  129 {
  130         struct ifaddr *ifa;
  131         struct sockaddr_dl *sdl;
  132         char *addr;
  133         size_t addrlen;
  134         static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
  135         static u_int8_t allone[8] =
  136                 { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  137 
  138         TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
  139                 if (ifa->ifa_addr->sa_family != AF_LINK)
  140                         continue;
  141                 sdl = (struct sockaddr_dl *)ifa->ifa_addr;
  142                 if (sdl == NULL)
  143                         continue;
  144                 if (sdl->sdl_alen == 0)
  145                         continue;
  146 
  147                 goto found;
  148         }
  149 
  150         return -1;
  151 
  152 found:
  153         addr = LLADDR(sdl);
  154         addrlen = sdl->sdl_alen;
  155 
  156         switch (ifp->if_type) {
  157         case IFT_IEEE1394:
  158         case IFT_IEEE80211:
  159                 /* IEEE1394 uses 16byte length address starting with EUI64 */
  160                 if (addrlen > 8)
  161                         addrlen = 8;
  162                 break;
  163         default:
  164                 break;
  165         }
  166 
  167         /* get EUI64 */
  168         switch (ifp->if_type) {
  169         /* IEEE802/EUI64 cases - what others? */
  170         case IFT_ETHER:
  171         case IFT_CARP:
  172         case IFT_FDDI:
  173         case IFT_ATM:
  174         case IFT_IEEE1394:
  175         case IFT_IEEE80211:
  176                 /* look at IEEE802/EUI64 only */
  177                 if (addrlen != 8 && addrlen != 6)
  178                         return -1;
  179 
  180                 /*
  181                  * check for invalid MAC address - on bsdi, we see it a lot
  182                  * since wildboar configures all-zero MAC on pccard before
  183                  * card insertion.
  184                  */
  185                 if (bcmp(addr, allzero, addrlen) == 0)
  186                         return -1;
  187                 if (bcmp(addr, allone, addrlen) == 0)
  188                         return -1;
  189 
  190                 /* make EUI64 address */
  191                 if (addrlen == 8)
  192                         bcopy(addr, &in6->s6_addr[8], 8);
  193                 else if (addrlen == 6) {
  194                         in6->s6_addr[8] = addr[0];
  195                         in6->s6_addr[9] = addr[1];
  196                         in6->s6_addr[10] = addr[2];
  197                         in6->s6_addr[11] = 0xff;
  198                         in6->s6_addr[12] = 0xfe;
  199                         in6->s6_addr[13] = addr[3];
  200                         in6->s6_addr[14] = addr[4];
  201                         in6->s6_addr[15] = addr[5];
  202                 }
  203                 break;
  204 
  205         case IFT_GIF:
  206                 /*
  207                  * RFC2893 says: "SHOULD use IPv4 address as ifid source".
  208                  * however, IPv4 address is not very suitable as unique
  209                  * identifier source (can be renumbered).
  210                  * we don't do this.
  211                  */
  212                 return -1;
  213 
  214         default:
  215                 return -1;
  216         }
  217 
  218         /* sanity check: g bit must not indicate "group" */
  219         if (EUI64_GROUP(in6))
  220                 return -1;
  221 
  222         /* convert EUI64 into IPv6 interface identifier */
  223         EUI64_TO_IFID(in6);
  224 
  225         /*
  226          * sanity check: ifid must not be all zero, avoid conflict with
  227          * subnet router anycast
  228          */
  229         if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
  230             bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
  231                 return -1;
  232         }
  233 
  234         return 0;
  235 }
  236 
  237 /*
  238  * Get interface identifier for the specified interface.  If it is not
  239  * available on ifp0, borrow interface identifier from other information
  240  * sources.
  241  */
  242 static int
  243 get_ifid(ifp0, altifp, in6)
  244         struct ifnet *ifp0;
  245         struct ifnet *altifp;   /* secondary EUI64 source */
  246         struct in6_addr *in6;
  247 {
  248         struct ifnet *ifp;
  249 
  250         /* first, try to get it from the interface itself */
  251         if (get_hw_ifid(ifp0, in6) == 0) {
  252                 nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
  253                     ifp0->if_xname));
  254                 goto success;
  255         }
  256 
  257         /* try secondary EUI64 source. this basically is for ATM PVC */
  258         if (altifp && get_hw_ifid(altifp, in6) == 0) {
  259                 nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
  260                     ifp0->if_xname, altifp->if_xname));
  261                 goto success;
  262         }
  263 
  264         /* next, try to get it from some other hardware interface */
  265         TAILQ_FOREACH(ifp, &ifnet, if_list) {
  266                 if (ifp == ifp0)
  267                         continue;
  268                 if (get_hw_ifid(ifp, in6) != 0)
  269                         continue;
  270 
  271                 /*
  272                  * to borrow ifid from other interface, ifid needs to be
  273                  * globally unique
  274                  */
  275                 if (IFID_UNIVERSAL(in6)) {
  276                         nd6log((LOG_DEBUG,
  277                             "%s: borrow interface identifier from %s\n",
  278                             ifp0->if_xname, ifp->if_xname));
  279                         goto success;
  280                 }
  281         }
  282 
  283         /* last resort: get from random number source */
  284         if (get_rand_ifid(ifp, in6) == 0) {
  285                 nd6log((LOG_DEBUG,
  286                     "%s: interface identifier generated by random number\n",
  287                     ifp0->if_xname));
  288                 goto success;
  289         }
  290 
  291         printf("%s: failed to get interface identifier\n", ifp0->if_xname);
  292         return -1;
  293 
  294 success:
  295         nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
  296             ifp0->if_xname, in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
  297             in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
  298             in6->s6_addr[14], in6->s6_addr[15]));
  299         return 0;
  300 }
  301 
  302 int
  303 in6_ifattach_linklocal(ifp, altifp)
  304         struct ifnet *ifp;
  305         struct ifnet *altifp;   /*secondary EUI64 source*/
  306 {
  307         struct in6_ifaddr *ia;
  308         struct in6_aliasreq ifra;
  309         struct nd_prefix pr0;
  310         int i, error;
  311 
  312         /*
  313          * configure link-local address.
  314          */
  315         bzero(&ifra, sizeof(ifra));
  316 
  317         /*
  318          * in6_update_ifa() does not use ifra_name, but we accurately set it
  319          * for safety.
  320          */
  321         strncpy(ifra.ifra_name, ifp->if_xname, sizeof(ifra.ifra_name));
  322 
  323         ifra.ifra_addr.sin6_family = AF_INET6;
  324         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
  325         ifra.ifra_addr.sin6_addr.s6_addr16[0] = htons(0xfe80);
  326         ifra.ifra_addr.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
  327         ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
  328         if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
  329                 ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
  330                 ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
  331         } else {
  332                 if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
  333                         nd6log((LOG_ERR,
  334                             "%s: no ifid available\n", ifp->if_xname));
  335                         return (-1);
  336                 }
  337         }
  338 
  339         ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
  340         ifra.ifra_prefixmask.sin6_family = AF_INET6;
  341         ifra.ifra_prefixmask.sin6_addr = in6mask64;
  342         /* link-local addresses should NEVER expire. */
  343         ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
  344         ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
  345 
  346         /*
  347          * Do not let in6_update_ifa() do DAD, since we need a random delay
  348          * before sending an NS at the first time the interface becomes up.
  349          * Instead, in6_if_up() will start DAD with a proper random delay.
  350          */
  351         ifra.ifra_flags |= IN6_IFF_NODAD;
  352 
  353         /*
  354          * Now call in6_update_ifa() to do a bunch of procedures to configure
  355          * a link-local address. In the case of CARP, we may be called after
  356          * one has already been configured, so check if it's already there
  357          * with in6ifa_ifpforlinklocal() and clobber it if it exists.
  358          */
  359         if ((error = in6_update_ifa(ifp, &ifra,
  360              in6ifa_ifpforlinklocal(ifp, 0))) != 0) {
  361                 /*
  362                  * XXX: When the interface does not support IPv6, this call
  363                  * would fail in the SIOCSIFADDR ioctl.  I believe the
  364                  * notification is rather confusing in this case, so just
  365                  * suppress it.  (jinmei@kame.net 20010130)
  366                  */
  367                 if (error != EAFNOSUPPORT)
  368                         nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
  369                             "configure a link-local address on %s "
  370                             "(errno=%d)\n",
  371                             ifp->if_xname, error));
  372                 return (-1);
  373         }
  374 
  375         /*
  376          * Adjust ia6_flags so that in6_if_up will perform DAD.
  377          * XXX: Some P2P interfaces seem not to send packets just after
  378          * becoming up, so we skip p2p interfaces for safety.
  379          */
  380         ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */
  381 #ifdef DIAGNOSTIC
  382         if (!ia) {
  383                 panic("ia == NULL in in6_ifattach_linklocal");
  384                 /* NOTREACHED */
  385         }
  386 #endif
  387         if (in6if_do_dad(ifp) && ((ifp->if_flags & IFF_POINTOPOINT) ||
  388             (ifp->if_type == IFT_CARP)) == 0) {
  389                 ia->ia6_flags &= ~IN6_IFF_NODAD;
  390                 ia->ia6_flags |= IN6_IFF_TENTATIVE;
  391         }
  392 
  393         /*
  394          * Make the link-local prefix (fe80::/64%link) as on-link.
  395          * Since we'd like to manage prefixes separately from addresses,
  396          * we make an ND6 prefix structure for the link-local prefix,
  397          * and add it to the prefix list as a never-expire prefix.
  398          * XXX: this change might affect some existing code base...
  399          */
  400         bzero(&pr0, sizeof(pr0));
  401         pr0.ndpr_ifp = ifp;
  402         /* this should be 64 at this moment. */
  403         pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
  404         pr0.ndpr_mask = ifra.ifra_prefixmask.sin6_addr;
  405         pr0.ndpr_prefix = ifra.ifra_addr;
  406         /* apply the mask for safety. (nd6_prelist_add will apply it again) */
  407         for (i = 0; i < 4; i++) {
  408                 pr0.ndpr_prefix.sin6_addr.s6_addr32[i] &=
  409                     in6mask64.s6_addr32[i];
  410         }
  411         /*
  412          * Initialize parameters.  The link-local prefix must always be
  413          * on-link, and its lifetimes never expire.
  414          */
  415         pr0.ndpr_raf_onlink = 1;
  416         pr0.ndpr_raf_auto = 1;  /* probably meaningless */
  417         pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
  418         pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
  419         /*
  420          * Since there is no other link-local addresses, nd6_prefix_lookup()
  421          * probably returns NULL.  However, we cannot always expect the result.
  422          * For example, if we first remove the (only) existing link-local
  423          * address, and then reconfigure another one, the prefix is still
  424          * valid with referring to the old link-local address.
  425          */
  426         if (nd6_prefix_lookup(&pr0) == NULL) {
  427                 if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
  428                         return (error);
  429         }
  430 
  431         return 0;
  432 }
  433 
  434 static int
  435 in6_ifattach_loopback(ifp)
  436         struct ifnet *ifp;      /* must be IFT_LOOP */
  437 {
  438         struct in6_aliasreq ifra;
  439         int error;
  440 
  441         bzero(&ifra, sizeof(ifra));
  442 
  443         /*
  444          * in6_update_ifa() does not use ifra_name, but we accurately set it
  445          * for safety.
  446          */
  447         strncpy(ifra.ifra_name, ifp->if_xname, sizeof(ifra.ifra_name));
  448 
  449         ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
  450         ifra.ifra_prefixmask.sin6_family = AF_INET6;
  451         ifra.ifra_prefixmask.sin6_addr = in6mask128;
  452 
  453         /*
  454          * Always initialize ia_dstaddr (= broadcast address) to loopback
  455          * address.  Follows IPv4 practice - see in_ifinit().
  456          */
  457         ifra.ifra_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
  458         ifra.ifra_dstaddr.sin6_family = AF_INET6;
  459         ifra.ifra_dstaddr.sin6_addr = in6addr_loopback;
  460 
  461         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
  462         ifra.ifra_addr.sin6_family = AF_INET6;
  463         ifra.ifra_addr.sin6_addr = in6addr_loopback;
  464 
  465         /* the loopback  address should NEVER expire. */
  466         ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
  467         ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
  468 
  469         /* we don't need to perform DAD on loopback interfaces. */
  470         ifra.ifra_flags |= IN6_IFF_NODAD;
  471 
  472         /*
  473          * We are sure that this is a newly assigned address, so we can set
  474          * NULL to the 3rd arg.
  475          */
  476         if ((error = in6_update_ifa(ifp, &ifra, NULL)) != 0) {
  477                 nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
  478                     "the loopback address on %s (errno=%d)\n",
  479                     ifp->if_xname, error));
  480                 return (-1);
  481         }
  482 
  483         return 0;
  484 }
  485 
  486 /*
  487  * compute NI group address, based on the current hostname setting.
  488  * see draft-ietf-ipngwg-icmp-name-lookup-* (04 and later).
  489  *
  490  * when ifp == NULL, the caller is responsible for filling scopeid.
  491  */
  492 int
  493 in6_nigroup(ifp, name, namelen, sa6)
  494         struct ifnet *ifp;
  495         const char *name;
  496         int namelen;
  497         struct sockaddr_in6 *sa6;
  498 {
  499         const char *p;
  500         u_int8_t *q;
  501         MD5_CTX ctxt;
  502         u_int8_t digest[16];
  503         u_int8_t l;
  504         u_int8_t n[64]; /* a single label must not exceed 63 chars */
  505 
  506         if (!namelen || !name)
  507                 return -1;
  508 
  509         p = name;
  510         while (p && *p && *p != '.' && p - name < namelen)
  511                 p++;
  512         if (p - name > sizeof(n) - 1)
  513                 return -1;      /* label too long */
  514         l = p - name;
  515         strncpy((char *)n, name, l);
  516         n[(int)l] = '\0';
  517         for (q = n; *q; q++) {
  518                 if ('A' <= *q && *q <= 'Z')
  519                         *q = *q - 'A' + 'a';
  520         }
  521 
  522         /* generate 8 bytes of pseudo-random value. */
  523         bzero(&ctxt, sizeof(ctxt));
  524         MD5Init(&ctxt);
  525         MD5Update(&ctxt, &l, sizeof(l));
  526         MD5Update(&ctxt, n, l);
  527         MD5Final(digest, &ctxt);
  528 
  529         bzero(sa6, sizeof(*sa6));
  530         sa6->sin6_family = AF_INET6;
  531         sa6->sin6_len = sizeof(*sa6);
  532         sa6->sin6_addr.s6_addr16[0] = htons(0xff02);
  533         sa6->sin6_addr.s6_addr16[1] = htons(ifp->if_index);
  534         sa6->sin6_addr.s6_addr8[11] = 2;
  535         bcopy(digest, &sa6->sin6_addr.s6_addr32[3],
  536             sizeof(sa6->sin6_addr.s6_addr32[3]));
  537 
  538         return 0;
  539 }
  540 
  541 /*
  542  * XXX multiple loopback interface needs more care.  for instance,
  543  * nodelocal address needs to be configured onto only one of them.
  544  * XXX multiple link-local address case
  545  */
  546 void
  547 in6_ifattach(ifp, altifp)
  548         struct ifnet *ifp;
  549         struct ifnet *altifp;   /* secondary EUI64 source */
  550 {
  551         struct in6_ifaddr *ia;
  552         struct in6_addr in6;
  553 
  554         /* some of the interfaces are inherently not IPv6 capable */
  555         switch (ifp->if_type) {
  556         case IFT_BRIDGE:
  557         case IFT_ENC:
  558         case IFT_PFLOG:
  559         case IFT_PFSYNC:
  560                 return;
  561         }
  562 
  563         /*
  564          * if link mtu is too small, don't try to configure IPv6.
  565          * remember there could be some link-layer that has special
  566          * fragmentation logic.
  567          */
  568         if (ifp->if_mtu < IPV6_MMTU) {
  569                 nd6log((LOG_INFO, "in6_ifattach: "
  570                     "%s has too small MTU, IPv6 not enabled\n",
  571                     ifp->if_xname));
  572                 return;
  573         }
  574 
  575         /* create a multicast kludge storage (if we have not had one) */
  576         in6_createmkludge(ifp);
  577 
  578         /*
  579          * quirks based on interface type
  580          */
  581         switch (ifp->if_type) {
  582         /* we attach a link-local address when a vhid is assigned */
  583         case IFT_CARP:
  584                 return;
  585         default:
  586                 break;
  587         }
  588 
  589         /*
  590          * usually, we require multicast capability to the interface
  591          */
  592         if ((ifp->if_flags & IFF_MULTICAST) == 0) {
  593                 nd6log((LOG_INFO, "in6_ifattach: "
  594                     "%s is not multicast capable, IPv6 not enabled\n",
  595                     ifp->if_xname));
  596                 return;
  597         }
  598 
  599         /*
  600          * assign loopback address for loopback interface.
  601          * XXX multiple loopback interface case.
  602          */
  603         if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
  604                 in6 = in6addr_loopback;
  605                 if (in6ifa_ifpwithaddr(ifp, &in6) == NULL) {
  606                         if (in6_ifattach_loopback(ifp) != 0)
  607                                 return;
  608                 }
  609         }
  610 
  611         /*
  612          * assign a link-local address, if there's none.
  613          */
  614         if (ip6_auto_linklocal) {
  615                 ia = in6ifa_ifpforlinklocal(ifp, 0);
  616                 if (ia == NULL) {
  617                         if (in6_ifattach_linklocal(ifp, altifp) == 0) {
  618                                 /* linklocal address assigned */
  619                         } else {
  620                                 /* failed to assign linklocal address. bark? */
  621                         }
  622                 }
  623         }
  624 }
  625 
  626 /*
  627  * NOTE: in6_ifdetach() does not support loopback if at this moment.
  628  */
  629 void
  630 in6_ifdetach(ifp)
  631         struct ifnet *ifp;
  632 {
  633         struct in6_ifaddr *ia, *oia;
  634         struct ifaddr *ifa, *next;
  635         struct rtentry *rt;
  636         short rtflags;
  637         struct sockaddr_in6 sin6;
  638         struct in6_multi_mship *imm;
  639 
  640 #ifdef MROUTING
  641         /* remove ip6_mrouter stuff */
  642         ip6_mrouter_detach(ifp);
  643 #endif
  644 
  645         /* remove neighbor management table */
  646         nd6_purge(ifp);
  647 
  648         /* nuke any of IPv6 addresses we have */
  649         for (ifa = TAILQ_FIRST(&ifp->if_addrlist);
  650             ifa != TAILQ_END(&ifp->if_addrlist); ifa = next) {
  651                 next = TAILQ_NEXT(ifa, ifa_list);
  652                 if (ifa->ifa_addr->sa_family != AF_INET6)
  653                         continue;
  654                 in6_purgeaddr(ifa);
  655         }
  656 
  657         /* undo everything done by in6_ifattach(), just in case */
  658         for (ifa = TAILQ_FIRST(&ifp->if_addrlist);
  659             ifa != TAILQ_END(&ifp->if_addrlist); ifa = next) {
  660                 next = TAILQ_NEXT(ifa, ifa_list);
  661 
  662                 if (ifa->ifa_addr->sa_family != AF_INET6
  663                  || !IN6_IS_ADDR_LINKLOCAL(&satosin6(&ifa->ifa_addr)->sin6_addr)) {
  664                         continue;
  665                 }
  666 
  667                 ia = (struct in6_ifaddr *)ifa;
  668 
  669                 /*
  670                  * leave from multicast groups we have joined for the interface
  671                  */
  672                 while (!LIST_EMPTY(&ia->ia6_memberships)) {
  673                         imm = LIST_FIRST(&ia->ia6_memberships);
  674                         LIST_REMOVE(imm, i6mm_chain);
  675                         in6_leavegroup(imm);
  676                 }
  677 
  678                 /* remove from the routing table */
  679                 if ((ia->ia_flags & IFA_ROUTE) &&
  680                     (rt = rtalloc1((struct sockaddr *)&ia->ia_addr, 0, 0))) {
  681                         rtflags = rt->rt_flags;
  682                         rtfree(rt);
  683                         rtrequest(RTM_DELETE, (struct sockaddr *)&ia->ia_addr,
  684                             (struct sockaddr *)&ia->ia_addr,
  685                             (struct sockaddr *)&ia->ia_prefixmask,
  686                             rtflags, (struct rtentry **)0, 0);
  687                 }
  688 
  689                 /* remove from the linked list */
  690                 TAILQ_REMOVE(&ifp->if_addrlist, (struct ifaddr *)ia, ifa_list);
  691                 IFAFREE(&ia->ia_ifa);
  692 
  693                 /* also remove from the IPv6 address chain(itojun&jinmei) */
  694                 oia = ia;
  695                 if (oia == (ia = in6_ifaddr))
  696                         in6_ifaddr = ia->ia_next;
  697                 else {
  698                         while (ia->ia_next && (ia->ia_next != oia))
  699                                 ia = ia->ia_next;
  700                         if (ia->ia_next)
  701                                 ia->ia_next = oia->ia_next;
  702                         else {
  703                                 nd6log((LOG_ERR,
  704                                     "%s: didn't unlink in6ifaddr from list\n",
  705                                     ifp->if_xname));
  706                         }
  707                 }
  708 
  709                 IFAFREE(&oia->ia_ifa);
  710         }
  711 
  712         /* cleanup multicast address kludge table, if there is any */
  713         in6_purgemkludge(ifp);
  714 
  715         /*
  716          * remove neighbor management table.  we call it twice just to make
  717          * sure we nuke everything.  maybe we need just one call.
  718          * XXX: since the first call did not release addresses, some prefixes
  719          * might remain.  We should call nd6_purge() again to release the
  720          * prefixes after removing all addresses above.
  721          * (Or can we just delay calling nd6_purge until at this point?)
  722          */
  723         nd6_purge(ifp);
  724 
  725         /* remove route to link-local allnodes multicast (ff02::1) */
  726         bzero(&sin6, sizeof(sin6));
  727         sin6.sin6_len = sizeof(struct sockaddr_in6);
  728         sin6.sin6_family = AF_INET6;
  729         sin6.sin6_addr = in6addr_linklocal_allnodes;
  730         sin6.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
  731         rt = rtalloc1((struct sockaddr *)&sin6, 0, 0);
  732         if (rt && rt->rt_ifp == ifp) {
  733                 rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt),
  734                     rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0, 0);
  735                 rtfree(rt);
  736         }
  737 }

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