The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netinet6/in6_ifattach.c

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    1 /*      $NetBSD: in6_ifattach.c,v 1.85 2009/09/19 13:11:02 christos 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/cdefs.h>
   34 __KERNEL_RCSID(0, "$NetBSD: in6_ifattach.c,v 1.85 2009/09/19 13:11:02 christos Exp $");
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/kmem.h>
   39 #include <sys/malloc.h>
   40 #include <sys/socket.h>
   41 #include <sys/sockio.h>
   42 #include <sys/kernel.h>
   43 #include <sys/syslog.h>
   44 #include <sys/md5.h>
   45 #include <sys/socketvar.h>
   46 
   47 #include <net/if.h>
   48 #include <net/if_dl.h>
   49 #include <net/if_types.h>
   50 #include <net/route.h>
   51 
   52 #include <netinet/in.h>
   53 #include <netinet/in_var.h>
   54 
   55 #include <netinet/ip6.h>
   56 #include <netinet6/in6_ifattach.h>
   57 #include <netinet6/ip6_var.h>
   58 #include <netinet6/nd6.h>
   59 #include <netinet6/ip6_mroute.h>
   60 #include <netinet6/scope6_var.h>
   61 
   62 #include <net/net_osdep.h>
   63 
   64 unsigned long in6_maxmtu = 0;
   65 
   66 int ip6_auto_linklocal = 1;     /* enable by default */
   67 
   68 callout_t in6_tmpaddrtimer_ch;
   69 
   70 
   71 #if 0
   72 static int get_hostid_ifid(struct ifnet *, struct in6_addr *);
   73 #endif
   74 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
   75 static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
   76 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
   77 static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
   78 static int in6_ifattach_loopback(struct ifnet *);
   79 
   80 #define EUI64_GBIT      0x01
   81 #define EUI64_UBIT      0x02
   82 #define EUI64_TO_IFID(in6)      do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (/*CONSTCOND*/ 0)
   83 #define EUI64_GROUP(in6)        ((in6)->s6_addr[8] & EUI64_GBIT)
   84 #define EUI64_INDIVIDUAL(in6)   (!EUI64_GROUP(in6))
   85 #define EUI64_LOCAL(in6)        ((in6)->s6_addr[8] & EUI64_UBIT)
   86 #define EUI64_UNIVERSAL(in6)    (!EUI64_LOCAL(in6))
   87 
   88 #define IFID_LOCAL(in6)         (!EUI64_LOCAL(in6))
   89 #define IFID_UNIVERSAL(in6)     (!EUI64_UNIVERSAL(in6))
   90 
   91 #define GEN_TEMPID_RETRY_MAX 5
   92 
   93 #if 0
   94 /*
   95  * Generate a last-resort interface identifier from hostid.
   96  * works only for certain architectures (like sparc).
   97  * also, using hostid itself may constitute a privacy threat, much worse
   98  * than MAC addresses (hostids are used for software licensing).
   99  * maybe we should use MD5(hostid) instead.
  100  *
  101  * in6 - upper 64bits are preserved
  102  */
  103 static int
  104 get_hostid_ifid(struct ifnet *ifp, struct in6_addr *in6)
  105 {
  106         int off, len;
  107         static const uint8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
  108         static const uint8_t allone[8] =
  109             { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  110 
  111         if (!hostid)
  112                 return -1;
  113 
  114         /* get up to 8 bytes from the hostid field - should we get */
  115         len = (sizeof(hostid) > 8) ? 8 : sizeof(hostid);
  116         off = sizeof(*in6) - len;
  117         memcpy(&in6->s6_addr[off], &hostid, len);
  118 
  119         /* make sure we do not return anything bogus */
  120         if (memcmp(&in6->s6_addr[8], allzero, sizeof(allzero)))
  121                 return -1;
  122         if (memcmp(&in6->s6_addr[8], allone, sizeof(allone)))
  123                 return -1;
  124 
  125         /* make sure to set "u" bit to local, and "g" bit to individual. */
  126         in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */
  127         in6->s6_addr[8] |= EUI64_UBIT;  /* u bit to "local" */
  128 
  129         /* convert EUI64 into IPv6 interface identifier */
  130         EUI64_TO_IFID(in6);
  131 
  132         return 0;
  133 }
  134 #endif
  135 
  136 /*
  137  * Generate a last-resort interface identifier, when the machine has no
  138  * IEEE802/EUI64 address sources.
  139  * The goal here is to get an interface identifier that is
  140  * (1) random enough and (2) does not change across reboot.
  141  * We currently use MD5(hostname) for it.
  142  */
  143 static int
  144 get_rand_ifid(struct ifnet *ifp,
  145         struct in6_addr *in6)   /* upper 64bits are preserved */
  146 {
  147         MD5_CTX ctxt;
  148         u_int8_t digest[16];
  149 
  150 #if 0
  151         /* we need at least several letters as seed for ifid */
  152         if (hostnamelen < 3)
  153                 return -1;
  154 #endif
  155 
  156         /* generate 8 bytes of pseudo-random value. */
  157         memset(&ctxt, 0, sizeof(ctxt));
  158         MD5Init(&ctxt);
  159         MD5Update(&ctxt, (u_char *)hostname, hostnamelen);
  160         MD5Final(digest, &ctxt);
  161 
  162         /* assumes sizeof(digest) > sizeof(ifid) */
  163         memcpy(&in6->s6_addr[8], digest, 8);
  164 
  165         /* make sure to set "u" bit to local, and "g" bit to individual. */
  166         in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */
  167         in6->s6_addr[8] |= EUI64_UBIT;  /* u bit to "local" */
  168 
  169         /* convert EUI64 into IPv6 interface identifier */
  170         EUI64_TO_IFID(in6);
  171 
  172         return 0;
  173 }
  174 
  175 static int
  176 generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
  177 {
  178         MD5_CTX ctxt;
  179         u_int8_t seed[16], digest[16], nullbuf[8];
  180         u_int32_t val32;
  181         /*
  182          * interface ID for subnet anycast addresses.
  183          * XXX: we assume the unicast address range that requires IDs
  184          * in EUI-64 format.
  185          */
  186         static const uint8_t anycast_id[8] = { 0xfd, 0xff, 0xff, 0xff,
  187             0xff, 0xff, 0xff, 0x80 };
  188         static const uint8_t isatap_id[4] = { 0x00, 0x00, 0x5e, 0xfe };
  189         int badid, retry = 0;
  190 
  191         /* If there's no hisotry, start with a random seed. */
  192         memset(nullbuf, 0, sizeof(nullbuf));
  193         if (memcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
  194                 int i;
  195 
  196                 for (i = 0; i < 2; i++) {
  197                         val32 = arc4random();
  198                         memcpy(seed + sizeof(val32) * i, &val32, sizeof(val32));
  199                 }
  200         } else
  201                 memcpy(seed, seed0, 8);
  202 
  203         /* copy the right-most 64-bits of the given address */
  204         /* XXX assumption on the size of IFID */
  205         memcpy(&seed[8], seed1, 8);
  206 
  207   again:
  208         /* for debugging purposes only */
  209 #if 0
  210         {
  211                 int i;
  212 
  213                 printf("generate_tmp_ifid: new randomized ID from: ");
  214                 for (i = 0; i < 16; i++)
  215                         printf("%02x", seed[i]);
  216                 printf(" ");
  217         }
  218 #endif
  219 
  220         /* generate 16 bytes of pseudo-random value. */
  221         memset(&ctxt, 0, sizeof(ctxt));
  222         MD5Init(&ctxt);
  223         MD5Update(&ctxt, seed, sizeof(seed));
  224         MD5Final(digest, &ctxt);
  225 
  226         /*
  227          * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (3)
  228          * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
  229          * left-most bit is numbered 0) to zero.
  230          */
  231         memcpy(ret, digest, 8);
  232         ret[0] &= ~EUI64_UBIT;
  233 
  234         /*
  235          * Reject inappropriate identifiers according to
  236          * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (4)
  237          * At this moment, we reject following cases:
  238          * - all 0 identifier
  239          * - identifiers that conflict with reserved subnet anycast addresses,
  240          *   which are defined in RFC 2526.
  241          * - identifiers that conflict with ISATAP addresses
  242          * - identifiers used in our own addresses
  243          */
  244         badid = 0;
  245         if (memcmp(nullbuf, ret, sizeof(nullbuf)) == 0)
  246                 badid = 1;
  247         else if (memcmp(anycast_id, ret, 7) == 0 &&
  248             (anycast_id[7] & ret[7]) == anycast_id[7]) {
  249                 badid = 1;
  250         } else if (memcmp(isatap_id, ret, sizeof(isatap_id)) == 0)
  251                 badid = 1;
  252         else {
  253                 struct in6_ifaddr *ia;
  254 
  255                 for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
  256                         if (!memcmp(&ia->ia_addr.sin6_addr.s6_addr[8], 
  257                             ret, 8)) {
  258                                 badid = 1;
  259                                 break;
  260                         }
  261                 }
  262         }
  263 
  264         /*
  265          * In the event that an unacceptable identifier has been generated,
  266          * restart the process, using the right-most 64 bits of the MD5 digest
  267          * obtained in place of the history value.
  268          */
  269         if (badid) {
  270                 /* for debugging purposes only */
  271 #if 0
  272                 {
  273                         int i;
  274 
  275                         printf("unacceptable random ID: ");
  276                         for (i = 0; i < 16; i++)
  277                                 printf("%02x", digest[i]);
  278                         printf("\n");
  279                 }
  280 #endif
  281 
  282                 if (++retry < GEN_TEMPID_RETRY_MAX) {
  283                         memcpy(seed, &digest[8], 8);
  284                         goto again;
  285                 } else {
  286                         /*
  287                          * We're so unlucky.  Give up for now, and return
  288                          * all 0 IDs to tell the caller not to make a
  289                          * temporary address.
  290                          */
  291                         nd6log((LOG_NOTICE,
  292                             "generate_tmp_ifid: never found a good ID\n"));
  293                         memset(ret, 0, 8);
  294                 }
  295         }
  296 
  297         /*
  298          * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (6)
  299          * Take the rightmost 64-bits of the MD5 digest and save them in
  300          * stable storage as the history value to be used in the next
  301          * iteration of the algorithm.
  302          */
  303         memcpy(seed0, &digest[8], 8);
  304 
  305         /* for debugging purposes only */
  306 #if 0
  307         {
  308                 int i;
  309 
  310                 printf("to: ");
  311                 for (i = 0; i < 16; i++)
  312                         printf("%02x", digest[i]);
  313                 printf("\n");
  314         }
  315 #endif
  316 
  317         return 0;
  318 }
  319 
  320 /*
  321  * Get interface identifier for the specified interface.
  322  *
  323  * in6 - upper 64bits are preserved
  324  */
  325 int
  326 in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
  327 {
  328         struct ifaddr *ifa;
  329         const struct sockaddr_dl *sdl = NULL, *tsdl;
  330         const char *addr;
  331         size_t addrlen;
  332         static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
  333         static u_int8_t allone[8] =
  334                 { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  335 
  336         IFADDR_FOREACH(ifa, ifp) {
  337                 if (ifa->ifa_addr->sa_family != AF_LINK)
  338                         continue;
  339                 tsdl = satocsdl(ifa->ifa_addr);
  340                 if (tsdl == NULL || tsdl->sdl_alen == 0)
  341                         continue;
  342                 if (sdl == NULL || ifa == ifp->if_dl || ifa == ifp->if_hwdl)
  343                         sdl = tsdl;
  344                 if (ifa == ifp->if_hwdl)
  345                         break;
  346         }
  347 
  348         if (sdl == NULL)
  349                 return -1;
  350 
  351         addr = CLLADDR(sdl);
  352         addrlen = sdl->sdl_alen;
  353 
  354         switch (ifp->if_type) {
  355         case IFT_IEEE1394:
  356         case IFT_IEEE80211:
  357                 /* IEEE1394 uses 16byte length address starting with EUI64 */
  358                 if (addrlen > 8)
  359                         addrlen = 8;
  360                 break;
  361         default:
  362                 break;
  363         }
  364 
  365         /* get EUI64 */
  366         switch (ifp->if_type) {
  367         /* IEEE802/EUI64 cases - what others? */
  368         case IFT_ETHER:
  369         case IFT_FDDI:
  370         case IFT_ATM:
  371         case IFT_IEEE1394:
  372         case IFT_IEEE80211:
  373                 /* look at IEEE802/EUI64 only */
  374                 if (addrlen != 8 && addrlen != 6)
  375                         return -1;
  376 
  377                 /*
  378                  * check for invalid MAC address - on bsdi, we see it a lot
  379                  * since wildboar configures all-zero MAC on pccard before
  380                  * card insertion.
  381                  */
  382                 if (memcmp(addr, allzero, addrlen) == 0)
  383                         return -1;
  384                 if (memcmp(addr, allone, addrlen) == 0)
  385                         return -1;
  386 
  387                 /* make EUI64 address */
  388                 if (addrlen == 8)
  389                         memcpy(&in6->s6_addr[8], addr, 8);
  390                 else if (addrlen == 6) {
  391                         in6->s6_addr[8] = addr[0];
  392                         in6->s6_addr[9] = addr[1];
  393                         in6->s6_addr[10] = addr[2];
  394                         in6->s6_addr[11] = 0xff;
  395                         in6->s6_addr[12] = 0xfe;
  396                         in6->s6_addr[13] = addr[3];
  397                         in6->s6_addr[14] = addr[4];
  398                         in6->s6_addr[15] = addr[5];
  399                 }
  400                 break;
  401 
  402         case IFT_ARCNET:
  403                 if (addrlen != 1)
  404                         return -1;
  405                 if (!addr[0])
  406                         return -1;
  407 
  408                 memset(&in6->s6_addr[8], 0, 8);
  409                 in6->s6_addr[15] = addr[0];
  410 
  411                 /*
  412                  * due to insufficient bitwidth, we mark it local.
  413                  */
  414                 in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */
  415                 in6->s6_addr[8] |= EUI64_UBIT;  /* u bit to "local" */
  416                 break;
  417 
  418         case IFT_GIF:
  419 #ifdef IFT_STF
  420         case IFT_STF:
  421 #endif
  422                 /*
  423                  * RFC2893 says: "SHOULD use IPv4 address as ifid source".
  424                  * however, IPv4 address is not very suitable as unique
  425                  * identifier source (can be renumbered).
  426                  * we don't do this.
  427                  */
  428                 return -1;
  429 
  430         default:
  431                 return -1;
  432         }
  433 
  434         /* sanity check: g bit must not indicate "group" */
  435         if (EUI64_GROUP(in6))
  436                 return -1;
  437 
  438         /* convert EUI64 into IPv6 interface identifier */
  439         EUI64_TO_IFID(in6);
  440 
  441         /*
  442          * sanity check: ifid must not be all zero, avoid conflict with
  443          * subnet router anycast
  444          */
  445         if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
  446             memcmp(&in6->s6_addr[9], allzero, 7) == 0) {
  447                 return -1;
  448         }
  449 
  450         return 0;
  451 }
  452 
  453 /*
  454  * Get interface identifier for the specified interface.  If it is not
  455  * available on ifp0, borrow interface identifier from other information
  456  * sources.
  457  *
  458  * altifp - secondary EUI64 source
  459  */
  460 static int
  461 get_ifid(struct ifnet *ifp0, struct ifnet *altifp, 
  462         struct in6_addr *in6)
  463 {
  464         struct ifnet *ifp;
  465 
  466         /* first, try to get it from the interface itself */
  467         if (in6_get_hw_ifid(ifp0, in6) == 0) {
  468                 nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
  469                     if_name(ifp0)));
  470                 goto success;
  471         }
  472 
  473         /* try secondary EUI64 source. this basically is for ATM PVC */
  474         if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
  475                 nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
  476                     if_name(ifp0), if_name(altifp)));
  477                 goto success;
  478         }
  479 
  480         /* next, try to get it from some other hardware interface */
  481         TAILQ_FOREACH(ifp, &ifnet, if_list) {
  482                 if (ifp == ifp0)
  483                         continue;
  484                 if (in6_get_hw_ifid(ifp, in6) != 0)
  485                         continue;
  486 
  487                 /*
  488                  * to borrow ifid from other interface, ifid needs to be
  489                  * globally unique
  490                  */
  491                 if (IFID_UNIVERSAL(in6)) {
  492                         nd6log((LOG_DEBUG,
  493                             "%s: borrow interface identifier from %s\n",
  494                             if_name(ifp0), if_name(ifp)));
  495                         goto success;
  496                 }
  497         }
  498 
  499 #if 0
  500         /* get from hostid - only for certain architectures */
  501         if (get_hostid_ifid(ifp, in6) == 0) {
  502                 nd6log((LOG_DEBUG,
  503                     "%s: interface identifier generated by hostid\n",
  504                     if_name(ifp0)));
  505                 goto success;
  506         }
  507 #endif
  508 
  509         /* last resort: get from random number source */
  510         if (get_rand_ifid(ifp, in6) == 0) {
  511                 nd6log((LOG_DEBUG,
  512                     "%s: interface identifier generated by random number\n",
  513                     if_name(ifp0)));
  514                 goto success;
  515         }
  516 
  517         printf("%s: failed to get interface identifier\n", if_name(ifp0));
  518         return -1;
  519 
  520 success:
  521         nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
  522             if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
  523             in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
  524             in6->s6_addr[14], in6->s6_addr[15]));
  525         return 0;
  526 }
  527 
  528 /*
  529  * altifp - secondary EUI64 source
  530  */
  531 
  532 static int
  533 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
  534 {
  535         struct in6_ifaddr *ia;
  536         struct in6_aliasreq ifra;
  537         struct nd_prefixctl pr0;
  538         int i, error;
  539 
  540         /*
  541          * configure link-local address.
  542          */
  543         memset(&ifra, 0, sizeof(ifra));
  544 
  545         /*
  546          * in6_update_ifa() does not use ifra_name, but we accurately set it
  547          * for safety.
  548          */
  549         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
  550 
  551         ifra.ifra_addr.sin6_family = AF_INET6;
  552         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
  553         ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
  554         ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
  555         if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
  556                 ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
  557                 ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
  558         } else {
  559                 if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
  560                         nd6log((LOG_ERR,
  561                             "%s: no ifid available\n", if_name(ifp)));
  562                         return -1;
  563                 }
  564         }
  565         if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
  566                 return -1;
  567 
  568         sockaddr_in6_init(&ifra.ifra_prefixmask, &in6mask64, 0, 0, 0);
  569         /* link-local addresses should NEVER expire. */
  570         ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
  571         ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
  572 
  573         /*
  574          * Now call in6_update_ifa() to do a bunch of procedures to configure
  575          * a link-local address. We can set the 3rd argument to NULL, because
  576          * we know there's no other link-local address on the interface
  577          * and therefore we are adding one (instead of updating one).
  578          */
  579         if ((error = in6_update_ifa(ifp, &ifra, NULL,
  580             IN6_IFAUPDATE_DADDELAY)) != 0) {
  581                 /*
  582                  * XXX: When the interface does not support IPv6, this call
  583                  * would fail in the SIOCINITIFADDR ioctl.  I believe the
  584                  * notification is rather confusing in this case, so just
  585                  * suppress it.  (jinmei@kame.net 20010130)
  586                  */
  587                 if (error != EAFNOSUPPORT)
  588                         nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
  589                             "configure a link-local address on %s "
  590                             "(errno=%d)\n",
  591                             if_name(ifp), error));
  592                 return -1;
  593         }
  594 
  595         ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */
  596 #ifdef DIAGNOSTIC
  597         if (!ia) {
  598                 panic("ia == NULL in in6_ifattach_linklocal");
  599                 /* NOTREACHED */
  600         }
  601 #endif
  602 
  603         /*
  604          * Make the link-local prefix (fe80::/64%link) as on-link.
  605          * Since we'd like to manage prefixes separately from addresses,
  606          * we make an ND6 prefix structure for the link-local prefix,
  607          * and add it to the prefix list as a never-expire prefix.
  608          * XXX: this change might affect some existing code base...
  609          */
  610         memset(&pr0, 0, sizeof(pr0));
  611         pr0.ndpr_ifp = ifp;
  612         /* this should be 64 at this moment. */
  613         pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
  614         pr0.ndpr_prefix = ifra.ifra_addr;
  615         /* apply the mask for safety. (nd6_prelist_add will apply it again) */
  616         for (i = 0; i < 4; i++) {
  617                 pr0.ndpr_prefix.sin6_addr.s6_addr32[i] &=
  618                     in6mask64.s6_addr32[i];
  619         }
  620         /*
  621          * Initialize parameters.  The link-local prefix must always be
  622          * on-link, and its lifetimes never expire.
  623          */
  624         pr0.ndpr_raf_onlink = 1;
  625         pr0.ndpr_raf_auto = 1;  /* probably meaningless */
  626         pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
  627         pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
  628         /*
  629          * Since there is no other link-local addresses, nd6_prefix_lookup()
  630          * probably returns NULL.  However, we cannot always expect the result.
  631          * For example, if we first remove the (only) existing link-local
  632          * address, and then reconfigure another one, the prefix is still
  633          * valid with referring to the old link-local address.
  634          */
  635         if (nd6_prefix_lookup(&pr0) == NULL) {
  636                 if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
  637                         return error;
  638         }
  639 
  640         return 0;
  641 }
  642 
  643 /*
  644  * ifp - mut be IFT_LOOP
  645  */
  646 
  647 static int
  648 in6_ifattach_loopback(struct ifnet *ifp)
  649 {
  650         struct in6_aliasreq ifra;
  651         int error;
  652 
  653         memset(&ifra, 0, sizeof(ifra));
  654 
  655         /*
  656          * in6_update_ifa() does not use ifra_name, but we accurately set it
  657          * for safety.
  658          */
  659         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
  660 
  661         sockaddr_in6_init(&ifra.ifra_prefixmask, &in6mask128, 0, 0, 0);
  662 
  663         /*
  664          * Always initialize ia_dstaddr (= broadcast address) to loopback
  665          * address.  Follows IPv4 practice - see in_ifinit().
  666          */
  667         sockaddr_in6_init(&ifra.ifra_dstaddr, &in6addr_loopback, 0, 0, 0);
  668 
  669         sockaddr_in6_init(&ifra.ifra_addr, &in6addr_loopback, 0, 0, 0);
  670 
  671         /* the loopback  address should NEVER expire. */
  672         ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
  673         ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
  674 
  675         /* we don't need to perform DAD on loopback interfaces. */
  676         ifra.ifra_flags |= IN6_IFF_NODAD;
  677 
  678         /*
  679          * We are sure that this is a newly assigned address, so we can set
  680          * NULL to the 3rd arg.
  681          */
  682         if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
  683                 nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
  684                     "the loopback address on %s (errno=%d)\n",
  685                     if_name(ifp), error));
  686                 return -1;
  687         }
  688 
  689         return 0;
  690 }
  691 
  692 /*
  693  * compute NI group address, based on the current hostname setting.
  694  * see draft-ietf-ipngwg-icmp-name-lookup-* (04 and later).
  695  *
  696  * when ifp == NULL, the caller is responsible for filling scopeid.
  697  */
  698 int
  699 in6_nigroup(struct ifnet *ifp, const char *name, int namelen, 
  700         struct sockaddr_in6 *sa6)
  701 {
  702         const char *p;
  703         u_int8_t *q;
  704         MD5_CTX ctxt;
  705         u_int8_t digest[16];
  706         u_int8_t l;
  707         u_int8_t n[64]; /* a single label must not exceed 63 chars */
  708 
  709         if (!namelen || !name)
  710                 return -1;
  711 
  712         p = name;
  713         while (p && *p && *p != '.' && p - name < namelen)
  714                 p++;
  715         if (p - name > sizeof(n) - 1)
  716                 return -1;      /* label too long */
  717         l = p - name;
  718         strncpy((char *)n, name, l);
  719         n[(int)l] = '\0';
  720         for (q = n; *q; q++) {
  721                 if ('A' <= *q && *q <= 'Z')
  722                         *q = *q - 'A' + 'a';
  723         }
  724 
  725         /* generate 8 bytes of pseudo-random value. */
  726         memset(&ctxt, 0, sizeof(ctxt));
  727         MD5Init(&ctxt);
  728         MD5Update(&ctxt, &l, sizeof(l));
  729         MD5Update(&ctxt, n, l);
  730         MD5Final(digest, &ctxt);
  731 
  732         memset(sa6, 0, sizeof(*sa6));
  733         sa6->sin6_family = AF_INET6;
  734         sa6->sin6_len = sizeof(*sa6);
  735         sa6->sin6_addr.s6_addr16[0] = htons(0xff02);
  736         sa6->sin6_addr.s6_addr8[11] = 2;
  737         memcpy(&sa6->sin6_addr.s6_addr32[3], digest,
  738             sizeof(sa6->sin6_addr.s6_addr32[3]));
  739         if (in6_setscope(&sa6->sin6_addr, ifp, NULL))
  740                 return -1; /* XXX: should not fail */
  741 
  742         return 0;
  743 }
  744 
  745 /*
  746  * XXX multiple loopback interface needs more care.  for instance,
  747  * nodelocal address needs to be configured onto only one of them.
  748  * XXX multiple link-local address case
  749  *
  750  * altifp - secondary EUI64 source
  751  */
  752 void
  753 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
  754 {
  755         struct in6_ifaddr *ia;
  756         struct in6_addr in6;
  757 
  758         /* some of the interfaces are inherently not IPv6 capable */
  759         switch (ifp->if_type) {
  760         case IFT_BRIDGE:
  761 #ifdef IFT_PFLOG
  762         case IFT_PFLOG:
  763 #endif
  764 #ifdef IFT_PFSYNC
  765         case IFT_PFSYNC:
  766 #endif
  767                 return;
  768         }
  769 
  770         /*
  771          * if link mtu is too small, don't try to configure IPv6.
  772          * remember there could be some link-layer that has special
  773          * fragmentation logic.
  774          */
  775         if (ifp->if_mtu < IPV6_MMTU) {
  776                 nd6log((LOG_INFO, "in6_ifattach: "
  777                     "%s has too small MTU, IPv6 not enabled\n",
  778                     if_name(ifp)));
  779                 return;
  780         }
  781 
  782         /* create a multicast kludge storage (if we have not had one) */
  783         in6_createmkludge(ifp);
  784 
  785         /*
  786          * quirks based on interface type
  787          */
  788         switch (ifp->if_type) {
  789 #ifdef IFT_STF
  790         case IFT_STF:
  791                 /*
  792                  * 6to4 interface is a very special kind of beast.
  793                  * no multicast, no linklocal.  RFC2529 specifies how to make
  794                  * linklocals for 6to4 interface, but there's no use and
  795                  * it is rather harmful to have one.
  796                  */
  797                 return;
  798 #endif
  799         case IFT_CARP:
  800                 return;
  801         default:
  802                 break;
  803         }
  804 
  805         /*
  806          * usually, we require multicast capability to the interface
  807          */
  808         if ((ifp->if_flags & IFF_MULTICAST) == 0) {
  809                 nd6log((LOG_INFO, "in6_ifattach: "
  810                     "%s is not multicast capable, IPv6 not enabled\n",
  811                     if_name(ifp)));
  812                 return;
  813         }
  814 
  815         /*
  816          * assign loopback address for loopback interface.
  817          * XXX multiple loopback interface case.
  818          */
  819         if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
  820                 in6 = in6addr_loopback;
  821                 if (in6ifa_ifpwithaddr(ifp, &in6) == NULL) {
  822                         if (in6_ifattach_loopback(ifp) != 0)
  823                                 return;
  824                 }
  825         }
  826 
  827         /*
  828          * assign a link-local address, if there's none.
  829          */
  830         if (ip6_auto_linklocal) {
  831                 ia = in6ifa_ifpforlinklocal(ifp, 0);
  832                 if (ia == NULL && in6_ifattach_linklocal(ifp, altifp) != 0) {
  833                         printf("%s: cannot assign link-local address\n",
  834                             ifp->if_xname);
  835                 }
  836         }
  837 }
  838 
  839 /*
  840  * NOTE: in6_ifdetach() does not support loopback if at this moment.
  841  * We don't need this function in bsdi, because interfaces are never removed
  842  * from the ifnet list in bsdi.
  843  */
  844 void
  845 in6_ifdetach(struct ifnet *ifp)
  846 {
  847         struct in6_ifaddr *ia, *oia;
  848         struct ifaddr *ifa, *next;
  849         struct rtentry *rt;
  850         short rtflags;
  851         struct in6_multi_mship *imm;
  852 
  853         /* remove ip6_mrouter stuff */
  854         ip6_mrouter_detach(ifp);
  855 
  856         /* remove neighbor management table */
  857         nd6_purge(ifp);
  858 
  859         /* XXX this code is duplicated in in6_purgeif() --dyoung */
  860         /* nuke any of IPv6 addresses we have */
  861         if_purgeaddrs(ifp, AF_INET6, in6_purgeaddr);
  862 
  863         /* XXX isn't this code is redundant, given the above? --dyoung */
  864         /* XXX doesn't this code replicate code in in6_purgeaddr() ? --dyoung */
  865         /* undo everything done by in6_ifattach(), just in case */
  866         for (ifa = IFADDR_FIRST(ifp); ifa != NULL; ifa = next) {
  867                 next = IFADDR_NEXT(ifa);
  868 
  869                 if (ifa->ifa_addr->sa_family != AF_INET6
  870                  || !IN6_IS_ADDR_LINKLOCAL(&satosin6(&ifa->ifa_addr)->sin6_addr)) {
  871                         continue;
  872                 }
  873 
  874                 ia = (struct in6_ifaddr *)ifa;
  875 
  876                 /*
  877                  * leave from multicast groups we have joined for the interface
  878                  */
  879                 while ((imm = LIST_FIRST(&ia->ia6_memberships)) != NULL) {
  880                         LIST_REMOVE(imm, i6mm_chain);
  881                         in6_leavegroup(imm);
  882                 }
  883 
  884                 /* remove from the routing table */
  885                 if ((ia->ia_flags & IFA_ROUTE) &&
  886                     (rt = rtalloc1((struct sockaddr *)&ia->ia_addr, 0))) {
  887                         rtflags = rt->rt_flags;
  888                         rtfree(rt);
  889                         rtrequest(RTM_DELETE, (struct sockaddr *)&ia->ia_addr,
  890                             (struct sockaddr *)&ia->ia_addr,
  891                             (struct sockaddr *)&ia->ia_prefixmask,
  892                             rtflags, (struct rtentry **)0);
  893                 }
  894 
  895                 /* remove from the linked list */
  896                 ifa_remove(ifp, &ia->ia_ifa);
  897 
  898                 /* also remove from the IPv6 address chain(itojun&jinmei) */
  899                 oia = ia;
  900                 if (oia == (ia = in6_ifaddr))
  901                         in6_ifaddr = ia->ia_next;
  902                 else {
  903                         while (ia->ia_next && (ia->ia_next != oia))
  904                                 ia = ia->ia_next;
  905                         if (ia->ia_next)
  906                                 ia->ia_next = oia->ia_next;
  907                         else {
  908                                 nd6log((LOG_ERR,
  909                                     "%s: didn't unlink in6ifaddr from list\n",
  910                                     if_name(ifp)));
  911                         }
  912                 }
  913 
  914                 IFAFREE(&oia->ia_ifa);
  915         }
  916 
  917         /* cleanup multicast address kludge table, if there is any */
  918         in6_purgemkludge(ifp);
  919 
  920         /*
  921          * remove neighbor management table.  we call it twice just to make
  922          * sure we nuke everything.  maybe we need just one call.
  923          * XXX: since the first call did not release addresses, some prefixes
  924          * might remain.  We should call nd6_purge() again to release the
  925          * prefixes after removing all addresses above.
  926          * (Or can we just delay calling nd6_purge until at this point?)
  927          */
  928         nd6_purge(ifp);
  929 }
  930 
  931 int
  932 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf, 
  933         const u_int8_t *baseid, int generate)
  934 {
  935         u_int8_t nullbuf[8];
  936         struct nd_ifinfo *ndi = ND_IFINFO(ifp);
  937 
  938         memset(nullbuf, 0, sizeof(nullbuf));
  939         if (memcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
  940                 /* we've never created a random ID.  Create a new one. */
  941                 generate = 1;
  942         }
  943 
  944         if (generate) {
  945                 memcpy(ndi->randomseed1, baseid, sizeof(ndi->randomseed1));
  946 
  947                 /* generate_tmp_ifid will update seedn and buf */
  948                 (void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
  949                     ndi->randomid);
  950         }
  951         memcpy(retbuf, ndi->randomid, 8);
  952         if (generate && memcmp(retbuf, nullbuf, sizeof(nullbuf)) == 0) {
  953                 /* generate_tmp_ifid could not found a good ID. */
  954                 return -1;
  955         }
  956 
  957         return 0;
  958 }
  959 
  960 void
  961 in6_tmpaddrtimer(void *ignored_arg)
  962 {
  963         struct nd_ifinfo *ndi;
  964         u_int8_t nullbuf[8];
  965         struct ifnet *ifp;
  966 
  967         mutex_enter(softnet_lock);
  968         KERNEL_LOCK(1, NULL);
  969 
  970         callout_reset(&in6_tmpaddrtimer_ch,
  971             (ip6_temp_preferred_lifetime - ip6_desync_factor -
  972             ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, NULL);
  973 
  974         memset(nullbuf, 0, sizeof(nullbuf));
  975         TAILQ_FOREACH(ifp, &ifnet, if_list) {
  976                 ndi = ND_IFINFO(ifp);
  977                 if (memcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
  978                         /*
  979                          * We've been generating a random ID on this interface.
  980                          * Create a new one.
  981                          */
  982                         (void)generate_tmp_ifid(ndi->randomseed0,
  983                             ndi->randomseed1, ndi->randomid);
  984                 }
  985         }
  986 
  987         KERNEL_UNLOCK_ONE(NULL);
  988         mutex_exit(softnet_lock);
  989 }

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