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

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    1 /*-
    2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 3. Neither the name of the project nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      $KAME: in6_ifattach.c,v 1.118 2001/05/24 07:44:00 itojun Exp $
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/9.2/sys/netinet6/in6_ifattach.c 253239 2013-07-12 01:52:31Z hrs $");
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/malloc.h>
   38 #include <sys/socket.h>
   39 #include <sys/sockio.h>
   40 #include <sys/jail.h>
   41 #include <sys/kernel.h>
   42 #include <sys/proc.h>
   43 #include <sys/syslog.h>
   44 #include <sys/md5.h>
   45 
   46 #include <net/if.h>
   47 #include <net/if_dl.h>
   48 #include <net/if_types.h>
   49 #include <net/route.h>
   50 #include <net/vnet.h>
   51 
   52 #include <netinet/in.h>
   53 #include <netinet/in_var.h>
   54 #include <netinet/if_ether.h>
   55 #include <netinet/in_pcb.h>
   56 #include <netinet/ip_var.h>
   57 #include <netinet/udp.h>
   58 #include <netinet/udp_var.h>
   59 
   60 #include <netinet/ip6.h>
   61 #include <netinet6/ip6_var.h>
   62 #include <netinet6/in6_var.h>
   63 #include <netinet6/in6_pcb.h>
   64 #include <netinet6/in6_ifattach.h>
   65 #include <netinet6/ip6_var.h>
   66 #include <netinet6/nd6.h>
   67 #include <netinet6/mld6_var.h>
   68 #include <netinet6/scope6_var.h>
   69 
   70 VNET_DEFINE(unsigned long, in6_maxmtu) = 0;
   71 
   72 #ifdef IP6_AUTO_LINKLOCAL
   73 VNET_DEFINE(int, ip6_auto_linklocal) = IP6_AUTO_LINKLOCAL;
   74 #else
   75 VNET_DEFINE(int, ip6_auto_linklocal) = 1;       /* enabled by default */
   76 #endif
   77 
   78 VNET_DEFINE(struct callout, in6_tmpaddrtimer_ch);
   79 #define V_in6_tmpaddrtimer_ch           VNET(in6_tmpaddrtimer_ch)
   80 
   81 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
   82 #define V_ripcbinfo                     VNET(ripcbinfo)
   83 
   84 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
   85 static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
   86 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
   87 static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
   88 static int in6_ifattach_loopback(struct ifnet *);
   89 static void in6_purgemaddrs(struct ifnet *);
   90 
   91 #define EUI64_GBIT      0x01
   92 #define EUI64_UBIT      0x02
   93 #define EUI64_TO_IFID(in6)      do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
   94 #define EUI64_GROUP(in6)        ((in6)->s6_addr[8] & EUI64_GBIT)
   95 #define EUI64_INDIVIDUAL(in6)   (!EUI64_GROUP(in6))
   96 #define EUI64_LOCAL(in6)        ((in6)->s6_addr[8] & EUI64_UBIT)
   97 #define EUI64_UNIVERSAL(in6)    (!EUI64_LOCAL(in6))
   98 
   99 #define IFID_LOCAL(in6)         (!EUI64_LOCAL(in6))
  100 #define IFID_UNIVERSAL(in6)     (!EUI64_UNIVERSAL(in6))
  101 
  102 /*
  103  * Generate a last-resort interface identifier, when the machine has no
  104  * IEEE802/EUI64 address sources.
  105  * The goal here is to get an interface identifier that is
  106  * (1) random enough and (2) does not change across reboot.
  107  * We currently use MD5(hostname) for it.
  108  *
  109  * in6 - upper 64bits are preserved
  110  */
  111 static int
  112 get_rand_ifid(struct ifnet *ifp, struct in6_addr *in6)
  113 {
  114         MD5_CTX ctxt;
  115         struct prison *pr;
  116         u_int8_t digest[16];
  117         int hostnamelen;
  118 
  119         pr = curthread->td_ucred->cr_prison;
  120         mtx_lock(&pr->pr_mtx);
  121         hostnamelen = strlen(pr->pr_hostname);
  122 #if 0
  123         /* we need at least several letters as seed for ifid */
  124         if (hostnamelen < 3) {
  125                 mtx_unlock(&pr->pr_mtx);
  126                 return -1;
  127         }
  128 #endif
  129 
  130         /* generate 8 bytes of pseudo-random value. */
  131         bzero(&ctxt, sizeof(ctxt));
  132         MD5Init(&ctxt);
  133         MD5Update(&ctxt, pr->pr_hostname, hostnamelen);
  134         mtx_unlock(&pr->pr_mtx);
  135         MD5Final(digest, &ctxt);
  136 
  137         /* assumes sizeof(digest) > sizeof(ifid) */
  138         bcopy(digest, &in6->s6_addr[8], 8);
  139 
  140         /* make sure to set "u" bit to local, and "g" bit to individual. */
  141         in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */
  142         in6->s6_addr[8] |= EUI64_UBIT;  /* u bit to "local" */
  143 
  144         /* convert EUI64 into IPv6 interface identifier */
  145         EUI64_TO_IFID(in6);
  146 
  147         return 0;
  148 }
  149 
  150 static int
  151 generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
  152 {
  153         MD5_CTX ctxt;
  154         u_int8_t seed[16], digest[16], nullbuf[8];
  155         u_int32_t val32;
  156 
  157         /* If there's no history, start with a random seed. */
  158         bzero(nullbuf, sizeof(nullbuf));
  159         if (bcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
  160                 int i;
  161 
  162                 for (i = 0; i < 2; i++) {
  163                         val32 = arc4random();
  164                         bcopy(&val32, seed + sizeof(val32) * i, sizeof(val32));
  165                 }
  166         } else
  167                 bcopy(seed0, seed, 8);
  168 
  169         /* copy the right-most 64-bits of the given address */
  170         /* XXX assumption on the size of IFID */
  171         bcopy(seed1, &seed[8], 8);
  172 
  173         if (0) {                /* for debugging purposes only */
  174                 int i;
  175 
  176                 printf("generate_tmp_ifid: new randomized ID from: ");
  177                 for (i = 0; i < 16; i++)
  178                         printf("%02x", seed[i]);
  179                 printf(" ");
  180         }
  181 
  182         /* generate 16 bytes of pseudo-random value. */
  183         bzero(&ctxt, sizeof(ctxt));
  184         MD5Init(&ctxt);
  185         MD5Update(&ctxt, seed, sizeof(seed));
  186         MD5Final(digest, &ctxt);
  187 
  188         /*
  189          * RFC 3041 3.2.1. (3)
  190          * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
  191          * left-most bit is numbered 0) to zero.
  192          */
  193         bcopy(digest, ret, 8);
  194         ret[0] &= ~EUI64_UBIT;
  195 
  196         /*
  197          * XXX: we'd like to ensure that the generated value is not zero
  198          * for simplicity.  If the caclculated digest happens to be zero,
  199          * use a random non-zero value as the last resort.
  200          */
  201         if (bcmp(nullbuf, ret, sizeof(nullbuf)) == 0) {
  202                 nd6log((LOG_INFO,
  203                     "generate_tmp_ifid: computed MD5 value is zero.\n"));
  204 
  205                 val32 = arc4random();
  206                 val32 = 1 + (val32 % (0xffffffff - 1));
  207         }
  208 
  209         /*
  210          * RFC 3041 3.2.1. (4)
  211          * Take the rightmost 64-bits of the MD5 digest and save them in
  212          * stable storage as the history value to be used in the next
  213          * iteration of the algorithm.
  214          */
  215         bcopy(&digest[8], seed0, 8);
  216 
  217         if (0) {                /* for debugging purposes only */
  218                 int i;
  219 
  220                 printf("to: ");
  221                 for (i = 0; i < 16; i++)
  222                         printf("%02x", digest[i]);
  223                 printf("\n");
  224         }
  225 
  226         return 0;
  227 }
  228 
  229 /*
  230  * Get interface identifier for the specified interface.
  231  * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
  232  *
  233  * in6 - upper 64bits are preserved
  234  */
  235 int
  236 in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
  237 {
  238         struct ifaddr *ifa;
  239         struct sockaddr_dl *sdl;
  240         u_int8_t *addr;
  241         size_t addrlen;
  242         static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
  243         static u_int8_t allone[8] =
  244                 { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  245 
  246         IF_ADDR_RLOCK(ifp);
  247         TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
  248                 if (ifa->ifa_addr->sa_family != AF_LINK)
  249                         continue;
  250                 sdl = (struct sockaddr_dl *)ifa->ifa_addr;
  251                 if (sdl == NULL)
  252                         continue;
  253                 if (sdl->sdl_alen == 0)
  254                         continue;
  255 
  256                 goto found;
  257         }
  258         IF_ADDR_RUNLOCK(ifp);
  259 
  260         return -1;
  261 
  262 found:
  263         IF_ADDR_LOCK_ASSERT(ifp);
  264         addr = LLADDR(sdl);
  265         addrlen = sdl->sdl_alen;
  266 
  267         /* get EUI64 */
  268         switch (ifp->if_type) {
  269         case IFT_BRIDGE:
  270         case IFT_ETHER:
  271         case IFT_L2VLAN:
  272         case IFT_FDDI:
  273         case IFT_ISO88025:
  274         case IFT_ATM:
  275         case IFT_IEEE1394:
  276 #ifdef IFT_IEEE80211
  277         case IFT_IEEE80211:
  278 #endif
  279                 /* IEEE802/EUI64 cases - what others? */
  280                 /* IEEE1394 uses 16byte length address starting with EUI64 */
  281                 if (addrlen > 8)
  282                         addrlen = 8;
  283 
  284                 /* look at IEEE802/EUI64 only */
  285                 if (addrlen != 8 && addrlen != 6) {
  286                         IF_ADDR_RUNLOCK(ifp);
  287                         return -1;
  288                 }
  289 
  290                 /*
  291                  * check for invalid MAC address - on bsdi, we see it a lot
  292                  * since wildboar configures all-zero MAC on pccard before
  293                  * card insertion.
  294                  */
  295                 if (bcmp(addr, allzero, addrlen) == 0) {
  296                         IF_ADDR_RUNLOCK(ifp);
  297                         return -1;
  298                 }
  299                 if (bcmp(addr, allone, addrlen) == 0) {
  300                         IF_ADDR_RUNLOCK(ifp);
  301                         return -1;
  302                 }
  303 
  304                 /* make EUI64 address */
  305                 if (addrlen == 8)
  306                         bcopy(addr, &in6->s6_addr[8], 8);
  307                 else if (addrlen == 6) {
  308                         in6->s6_addr[8] = addr[0];
  309                         in6->s6_addr[9] = addr[1];
  310                         in6->s6_addr[10] = addr[2];
  311                         in6->s6_addr[11] = 0xff;
  312                         in6->s6_addr[12] = 0xfe;
  313                         in6->s6_addr[13] = addr[3];
  314                         in6->s6_addr[14] = addr[4];
  315                         in6->s6_addr[15] = addr[5];
  316                 }
  317                 break;
  318 
  319         case IFT_ARCNET:
  320                 if (addrlen != 1) {
  321                         IF_ADDR_RUNLOCK(ifp);
  322                         return -1;
  323                 }
  324                 if (!addr[0]) {
  325                         IF_ADDR_RUNLOCK(ifp);
  326                         return -1;
  327                 }
  328 
  329                 bzero(&in6->s6_addr[8], 8);
  330                 in6->s6_addr[15] = addr[0];
  331 
  332                 /*
  333                  * due to insufficient bitwidth, we mark it local.
  334                  */
  335                 in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */
  336                 in6->s6_addr[8] |= EUI64_UBIT;  /* u bit to "local" */
  337                 break;
  338 
  339         case IFT_GIF:
  340 #ifdef IFT_STF
  341         case IFT_STF:
  342 #endif
  343                 /*
  344                  * RFC2893 says: "SHOULD use IPv4 address as ifid source".
  345                  * however, IPv4 address is not very suitable as unique
  346                  * identifier source (can be renumbered).
  347                  * we don't do this.
  348                  */
  349                 IF_ADDR_RUNLOCK(ifp);
  350                 return -1;
  351 
  352         default:
  353                 IF_ADDR_RUNLOCK(ifp);
  354                 return -1;
  355         }
  356 
  357         /* sanity check: g bit must not indicate "group" */
  358         if (EUI64_GROUP(in6)) {
  359                 IF_ADDR_RUNLOCK(ifp);
  360                 return -1;
  361         }
  362 
  363         /* convert EUI64 into IPv6 interface identifier */
  364         EUI64_TO_IFID(in6);
  365 
  366         /*
  367          * sanity check: ifid must not be all zero, avoid conflict with
  368          * subnet router anycast
  369          */
  370         if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
  371             bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
  372                 IF_ADDR_RUNLOCK(ifp);
  373                 return -1;
  374         }
  375 
  376         IF_ADDR_RUNLOCK(ifp);
  377         return 0;
  378 }
  379 
  380 /*
  381  * Get interface identifier for the specified interface.  If it is not
  382  * available on ifp0, borrow interface identifier from other information
  383  * sources.
  384  *
  385  * altifp - secondary EUI64 source
  386  */
  387 static int
  388 get_ifid(struct ifnet *ifp0, struct ifnet *altifp,
  389     struct in6_addr *in6)
  390 {
  391         struct ifnet *ifp;
  392 
  393         /* first, try to get it from the interface itself */
  394         if (in6_get_hw_ifid(ifp0, in6) == 0) {
  395                 nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
  396                     if_name(ifp0)));
  397                 goto success;
  398         }
  399 
  400         /* try secondary EUI64 source. this basically is for ATM PVC */
  401         if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
  402                 nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
  403                     if_name(ifp0), if_name(altifp)));
  404                 goto success;
  405         }
  406 
  407         /* next, try to get it from some other hardware interface */
  408         IFNET_RLOCK_NOSLEEP();
  409         TAILQ_FOREACH(ifp, &V_ifnet, if_list) {
  410                 if (ifp == ifp0)
  411                         continue;
  412                 if (in6_get_hw_ifid(ifp, in6) != 0)
  413                         continue;
  414 
  415                 /*
  416                  * to borrow ifid from other interface, ifid needs to be
  417                  * globally unique
  418                  */
  419                 if (IFID_UNIVERSAL(in6)) {
  420                         nd6log((LOG_DEBUG,
  421                             "%s: borrow interface identifier from %s\n",
  422                             if_name(ifp0), if_name(ifp)));
  423                         IFNET_RUNLOCK_NOSLEEP();
  424                         goto success;
  425                 }
  426         }
  427         IFNET_RUNLOCK_NOSLEEP();
  428 
  429         /* last resort: get from random number source */
  430         if (get_rand_ifid(ifp, in6) == 0) {
  431                 nd6log((LOG_DEBUG,
  432                     "%s: interface identifier generated by random number\n",
  433                     if_name(ifp0)));
  434                 goto success;
  435         }
  436 
  437         printf("%s: failed to get interface identifier\n", if_name(ifp0));
  438         return -1;
  439 
  440 success:
  441         nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
  442             if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
  443             in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
  444             in6->s6_addr[14], in6->s6_addr[15]));
  445         return 0;
  446 }
  447 
  448 /*
  449  * altifp - secondary EUI64 source
  450  */
  451 static int
  452 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
  453 {
  454         struct in6_ifaddr *ia;
  455         struct in6_aliasreq ifra;
  456         struct nd_prefixctl pr0;
  457         int i, error;
  458 
  459         /*
  460          * configure link-local address.
  461          */
  462         bzero(&ifra, sizeof(ifra));
  463 
  464         /*
  465          * in6_update_ifa() does not use ifra_name, but we accurately set it
  466          * for safety.
  467          */
  468         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
  469 
  470         ifra.ifra_addr.sin6_family = AF_INET6;
  471         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
  472         ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
  473         ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
  474         if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
  475                 ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
  476                 ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
  477         } else {
  478                 if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
  479                         nd6log((LOG_ERR,
  480                             "%s: no ifid available\n", if_name(ifp)));
  481                         return (-1);
  482                 }
  483         }
  484         if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
  485                 return (-1);
  486 
  487         ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
  488         ifra.ifra_prefixmask.sin6_family = AF_INET6;
  489         ifra.ifra_prefixmask.sin6_addr = in6mask64;
  490         /* link-local addresses should NEVER expire. */
  491         ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
  492         ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
  493 
  494         /*
  495          * Now call in6_update_ifa() to do a bunch of procedures to configure
  496          * a link-local address. We can set the 3rd argument to NULL, because
  497          * we know there's no other link-local address on the interface
  498          * and therefore we are adding one (instead of updating one).
  499          */
  500         if ((error = in6_update_ifa(ifp, &ifra, NULL,
  501                                     IN6_IFAUPDATE_DADDELAY)) != 0) {
  502                 /*
  503                  * XXX: When the interface does not support IPv6, this call
  504                  * would fail in the SIOCSIFADDR ioctl.  I believe the
  505                  * notification is rather confusing in this case, so just
  506                  * suppress it.  (jinmei@kame.net 20010130)
  507                  */
  508                 if (error != EAFNOSUPPORT)
  509                         nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
  510                             "configure a link-local address on %s "
  511                             "(errno=%d)\n",
  512                             if_name(ifp), error));
  513                 return (-1);
  514         }
  515 
  516         ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */
  517         KASSERT(ia != NULL, ("%s: ia == NULL, ifp=%p", __func__, ifp));
  518 
  519         ifa_free(&ia->ia_ifa);
  520 
  521         /*
  522          * Make the link-local prefix (fe80::%link/64) as on-link.
  523          * Since we'd like to manage prefixes separately from addresses,
  524          * we make an ND6 prefix structure for the link-local prefix,
  525          * and add it to the prefix list as a never-expire prefix.
  526          * XXX: this change might affect some existing code base...
  527          */
  528         bzero(&pr0, sizeof(pr0));
  529         pr0.ndpr_ifp = ifp;
  530         /* this should be 64 at this moment. */
  531         pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
  532         pr0.ndpr_prefix = ifra.ifra_addr;
  533         /* apply the mask for safety. (nd6_prelist_add will apply it again) */
  534         for (i = 0; i < 4; i++) {
  535                 pr0.ndpr_prefix.sin6_addr.s6_addr32[i] &=
  536                     in6mask64.s6_addr32[i];
  537         }
  538         /*
  539          * Initialize parameters.  The link-local prefix must always be
  540          * on-link, and its lifetimes never expire.
  541          */
  542         pr0.ndpr_raf_onlink = 1;
  543         pr0.ndpr_raf_auto = 1;  /* probably meaningless */
  544         pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
  545         pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
  546         /*
  547          * Since there is no other link-local addresses, nd6_prefix_lookup()
  548          * probably returns NULL.  However, we cannot always expect the result.
  549          * For example, if we first remove the (only) existing link-local
  550          * address, and then reconfigure another one, the prefix is still
  551          * valid with referring to the old link-local address.
  552          */
  553         if (nd6_prefix_lookup(&pr0) == NULL) {
  554                 if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
  555                         return (error);
  556         }
  557 
  558         return 0;
  559 }
  560 
  561 /*
  562  * ifp - must be IFT_LOOP
  563  */
  564 static int
  565 in6_ifattach_loopback(struct ifnet *ifp)
  566 {
  567         struct in6_aliasreq ifra;
  568         int error;
  569 
  570         bzero(&ifra, sizeof(ifra));
  571 
  572         /*
  573          * in6_update_ifa() does not use ifra_name, but we accurately set it
  574          * for safety.
  575          */
  576         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
  577 
  578         ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
  579         ifra.ifra_prefixmask.sin6_family = AF_INET6;
  580         ifra.ifra_prefixmask.sin6_addr = in6mask128;
  581 
  582         /*
  583          * Always initialize ia_dstaddr (= broadcast address) to loopback
  584          * address.  Follows IPv4 practice - see in_ifinit().
  585          */
  586         ifra.ifra_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
  587         ifra.ifra_dstaddr.sin6_family = AF_INET6;
  588         ifra.ifra_dstaddr.sin6_addr = in6addr_loopback;
  589 
  590         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
  591         ifra.ifra_addr.sin6_family = AF_INET6;
  592         ifra.ifra_addr.sin6_addr = in6addr_loopback;
  593 
  594         /* the loopback  address should NEVER expire. */
  595         ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
  596         ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
  597 
  598         /* we don't need to perform DAD on loopback interfaces. */
  599         ifra.ifra_flags |= IN6_IFF_NODAD;
  600 
  601         /* skip registration to the prefix list. XXX should be temporary. */
  602         ifra.ifra_flags |= IN6_IFF_NOPFX;
  603 
  604         /*
  605          * We are sure that this is a newly assigned address, so we can set
  606          * NULL to the 3rd arg.
  607          */
  608         if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
  609                 nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
  610                     "the loopback address on %s (errno=%d)\n",
  611                     if_name(ifp), error));
  612                 return (-1);
  613         }
  614 
  615         return 0;
  616 }
  617 
  618 /*
  619  * compute NI group address, based on the current hostname setting.
  620  * see RFC 4620.
  621  *
  622  * when ifp == NULL, the caller is responsible for filling scopeid.
  623  *
  624  * If oldmcprefix == 1, FF02:0:0:0:0:2::/96 is used for NI group address
  625  * while it is FF02:0:0:0:0:2:FF00::/104 in RFC 4620. 
  626  */
  627 static int
  628 in6_nigroup0(struct ifnet *ifp, const char *name, int namelen,
  629     struct in6_addr *in6, int oldmcprefix)
  630 {
  631         struct prison *pr;
  632         const char *p;
  633         u_char *q;
  634         MD5_CTX ctxt;
  635         u_int8_t digest[16];
  636         char l;
  637         char n[64];     /* a single label must not exceed 63 chars */
  638 
  639         /*
  640          * If no name is given and namelen is -1,
  641          * we try to do the hostname lookup ourselves.
  642          */
  643         if (!name && namelen == -1) {
  644                 pr = curthread->td_ucred->cr_prison;
  645                 mtx_lock(&pr->pr_mtx);
  646                 name = pr->pr_hostname;
  647                 namelen = strlen(name);
  648         } else
  649                 pr = NULL;
  650         if (!name || !namelen) {
  651                 if (pr != NULL)
  652                         mtx_unlock(&pr->pr_mtx);
  653                 return -1;
  654         }
  655 
  656         p = name;
  657         while (p && *p && *p != '.' && p - name < namelen)
  658                 p++;
  659         if (p == name || p - name > sizeof(n) - 1) {
  660                 if (pr != NULL)
  661                         mtx_unlock(&pr->pr_mtx);
  662                 return -1;      /* label too long */
  663         }
  664         l = p - name;
  665         strncpy(n, name, l);
  666         if (pr != NULL)
  667                 mtx_unlock(&pr->pr_mtx);
  668         n[(int)l] = '\0';
  669         for (q = n; *q; q++) {
  670                 if ('A' <= *q && *q <= 'Z')
  671                         *q = *q - 'A' + 'a';
  672         }
  673 
  674         /* generate 16 bytes of pseudo-random value. */
  675         bzero(&ctxt, sizeof(ctxt));
  676         MD5Init(&ctxt);
  677         MD5Update(&ctxt, &l, sizeof(l));
  678         MD5Update(&ctxt, n, l);
  679         MD5Final(digest, &ctxt);
  680 
  681         bzero(in6, sizeof(*in6));
  682         in6->s6_addr16[0] = IPV6_ADDR_INT16_MLL;
  683         in6->s6_addr8[11] = 2;
  684         if (oldmcprefix == 0) {
  685                 in6->s6_addr8[12] = 0xff;
  686                 /* Copy the first 24 bits of 128-bit hash into the address. */
  687                 bcopy(digest, &in6->s6_addr8[13], 3);
  688         } else {
  689                 /* Copy the first 32 bits of 128-bit hash into the address. */
  690                 bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
  691         }
  692         if (in6_setscope(in6, ifp, NULL))
  693                 return (-1); /* XXX: should not fail */
  694 
  695         return 0;
  696 }
  697 
  698 int
  699 in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
  700     struct in6_addr *in6)
  701 {
  702 
  703         return (in6_nigroup0(ifp, name, namelen, in6, 0));
  704 }
  705 
  706 int
  707 in6_nigroup_oldmcprefix(struct ifnet *ifp, const char *name, int namelen,
  708     struct in6_addr *in6)
  709 {
  710 
  711         return (in6_nigroup0(ifp, name, namelen, in6, 1));
  712 }
  713 
  714 /*
  715  * XXX multiple loopback interface needs more care.  for instance,
  716  * nodelocal address needs to be configured onto only one of them.
  717  * XXX multiple link-local address case
  718  *
  719  * altifp - secondary EUI64 source
  720  */
  721 void
  722 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
  723 {
  724         struct in6_ifaddr *ia;
  725         struct in6_addr in6;
  726 
  727         /* some of the interfaces are inherently not IPv6 capable */
  728         switch (ifp->if_type) {
  729         case IFT_PFLOG:
  730         case IFT_PFSYNC:
  731                 ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
  732                 ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED;
  733                 return;
  734         }
  735 
  736         /*
  737          * quirks based on interface type
  738          */
  739         switch (ifp->if_type) {
  740         case IFT_STF:
  741                 /*
  742                  * 6to4 interface is a very special kind of beast.
  743                  * no multicast, no linklocal.  RFC2529 specifies how to make
  744                  * linklocals for 6to4 interface, but there's no use and
  745                  * it is rather harmful to have one.
  746                  */
  747                 ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
  748                 break;
  749         default:
  750                 break;
  751         }
  752 
  753         /*
  754          * usually, we require multicast capability to the interface
  755          */
  756         if ((ifp->if_flags & IFF_MULTICAST) == 0) {
  757                 nd6log((LOG_INFO, "in6_ifattach: "
  758                     "%s is not multicast capable, IPv6 not enabled\n",
  759                     if_name(ifp)));
  760                 return;
  761         }
  762 
  763         /*
  764          * assign loopback address for loopback interface.
  765          * XXX multiple loopback interface case.
  766          */
  767         if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
  768                 struct ifaddr *ifa;
  769 
  770                 in6 = in6addr_loopback;
  771                 ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &in6);
  772                 if (ifa == NULL) {
  773                         if (in6_ifattach_loopback(ifp) != 0)
  774                                 return;
  775                 } else
  776                         ifa_free(ifa);
  777         }
  778 
  779         /*
  780          * assign a link-local address, if there's none.
  781          */
  782         if (!(ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) &&
  783             ND_IFINFO(ifp)->flags & ND6_IFF_AUTO_LINKLOCAL) {
  784                 int error;
  785 
  786                 ia = in6ifa_ifpforlinklocal(ifp, 0);
  787                 if (ia == NULL) {
  788                         error = in6_ifattach_linklocal(ifp, altifp);
  789 #if 0
  790                         if (error)
  791                                 log(LOG_NOTICE, "in6_ifattach_linklocal: "
  792                                     "failed to add a link-local addr to %s\n",
  793                                     if_name(ifp));
  794 #endif
  795                 } else
  796                         ifa_free(&ia->ia_ifa);
  797         }
  798 
  799         /* update dynamically. */
  800         if (V_in6_maxmtu < ifp->if_mtu)
  801                 V_in6_maxmtu = ifp->if_mtu;
  802 }
  803 
  804 /*
  805  * NOTE: in6_ifdetach() does not support loopback if at this moment.
  806  * We don't need this function in bsdi, because interfaces are never removed
  807  * from the ifnet list in bsdi.
  808  */
  809 void
  810 in6_ifdetach(struct ifnet *ifp)
  811 {
  812         struct in6_ifaddr *ia;
  813         struct ifaddr *ifa, *next;
  814         struct radix_node_head *rnh;
  815         struct rtentry *rt;
  816         struct sockaddr_in6 sin6;
  817         struct in6_multi_mship *imm;
  818 
  819         /* remove neighbor management table */
  820         nd6_purge(ifp);
  821 
  822         /* nuke any of IPv6 addresses we have */
  823         TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
  824                 if (ifa->ifa_addr->sa_family != AF_INET6)
  825                         continue;
  826                 in6_purgeaddr(ifa);
  827         }
  828 
  829         /* undo everything done by in6_ifattach(), just in case */
  830         TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
  831                 if (ifa->ifa_addr->sa_family != AF_INET6
  832                  || !IN6_IS_ADDR_LINKLOCAL(&satosin6(&ifa->ifa_addr)->sin6_addr)) {
  833                         continue;
  834                 }
  835 
  836                 ia = (struct in6_ifaddr *)ifa;
  837 
  838                 /*
  839                  * leave from multicast groups we have joined for the interface
  840                  */
  841                 while ((imm = LIST_FIRST(&ia->ia6_memberships)) != NULL) {
  842                         LIST_REMOVE(imm, i6mm_chain);
  843                         in6_leavegroup(imm);
  844                 }
  845 
  846                 /* Remove link-local from the routing table. */
  847                 if (ia->ia_flags & IFA_ROUTE)
  848                         (void)rtinit(&ia->ia_ifa, RTM_DELETE, ia->ia_flags);
  849 
  850                 /* remove from the linked list */
  851                 IF_ADDR_WLOCK(ifp);
  852                 TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
  853                 IF_ADDR_WUNLOCK(ifp);
  854                 ifa_free(ifa);                          /* if_addrhead */
  855 
  856                 IN6_IFADDR_WLOCK();
  857                 TAILQ_REMOVE(&V_in6_ifaddrhead, ia, ia_link);
  858                 IN6_IFADDR_WUNLOCK();
  859                 ifa_free(ifa);
  860         }
  861 
  862         in6_pcbpurgeif0(&V_udbinfo, ifp);
  863         in6_pcbpurgeif0(&V_ripcbinfo, ifp);
  864         /* leave from all multicast groups joined */
  865         in6_purgemaddrs(ifp);
  866 
  867         /*
  868          * remove neighbor management table.  we call it twice just to make
  869          * sure we nuke everything.  maybe we need just one call.
  870          * XXX: since the first call did not release addresses, some prefixes
  871          * might remain.  We should call nd6_purge() again to release the
  872          * prefixes after removing all addresses above.
  873          * (Or can we just delay calling nd6_purge until at this point?)
  874          */
  875         nd6_purge(ifp);
  876 
  877         /*
  878          * Remove route to link-local allnodes multicast (ff02::1).
  879          * These only get automatically installed for the default FIB.
  880          */
  881         bzero(&sin6, sizeof(sin6));
  882         sin6.sin6_len = sizeof(struct sockaddr_in6);
  883         sin6.sin6_family = AF_INET6;
  884         sin6.sin6_addr = in6addr_linklocal_allnodes;
  885         if (in6_setscope(&sin6.sin6_addr, ifp, NULL))
  886                 /* XXX: should not fail */
  887                 return;
  888         /* XXX grab lock first to avoid LOR */
  889         rnh = rt_tables_get_rnh(RT_DEFAULT_FIB, AF_INET6);
  890         if (rnh != NULL) {
  891                 RADIX_NODE_HEAD_LOCK(rnh);
  892                 rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, RTF_RNH_LOCKED,
  893                     RT_DEFAULT_FIB);
  894                 if (rt) {
  895                         if (rt->rt_ifp == ifp)
  896                                 rtexpunge(rt);
  897                         RTFREE_LOCKED(rt);
  898                 }
  899                 RADIX_NODE_HEAD_UNLOCK(rnh);
  900         }
  901 }
  902 
  903 int
  904 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf,
  905     const u_int8_t *baseid, int generate)
  906 {
  907         u_int8_t nullbuf[8];
  908         struct nd_ifinfo *ndi = ND_IFINFO(ifp);
  909 
  910         bzero(nullbuf, sizeof(nullbuf));
  911         if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
  912                 /* we've never created a random ID.  Create a new one. */
  913                 generate = 1;
  914         }
  915 
  916         if (generate) {
  917                 bcopy(baseid, ndi->randomseed1, sizeof(ndi->randomseed1));
  918 
  919                 /* generate_tmp_ifid will update seedn and buf */
  920                 (void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
  921                     ndi->randomid);
  922         }
  923         bcopy(ndi->randomid, retbuf, 8);
  924 
  925         return (0);
  926 }
  927 
  928 void
  929 in6_tmpaddrtimer(void *arg)
  930 {
  931         CURVNET_SET((struct vnet *) arg);
  932         struct nd_ifinfo *ndi;
  933         u_int8_t nullbuf[8];
  934         struct ifnet *ifp;
  935 
  936         callout_reset(&V_in6_tmpaddrtimer_ch,
  937             (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
  938             V_ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, curvnet);
  939 
  940         bzero(nullbuf, sizeof(nullbuf));
  941         TAILQ_FOREACH(ifp, &V_ifnet, if_list) {
  942                 ndi = ND_IFINFO(ifp);
  943                 if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
  944                         /*
  945                          * We've been generating a random ID on this interface.
  946                          * Create a new one.
  947                          */
  948                         (void)generate_tmp_ifid(ndi->randomseed0,
  949                             ndi->randomseed1, ndi->randomid);
  950                 }
  951         }
  952 
  953         CURVNET_RESTORE();
  954 }
  955 
  956 static void
  957 in6_purgemaddrs(struct ifnet *ifp)
  958 {
  959         LIST_HEAD(,in6_multi)    purgeinms;
  960         struct in6_multi        *inm, *tinm;
  961         struct ifmultiaddr      *ifma;
  962 
  963         LIST_INIT(&purgeinms);
  964         IN6_MULTI_LOCK();
  965 
  966         /*
  967          * Extract list of in6_multi associated with the detaching ifp
  968          * which the PF_INET6 layer is about to release.
  969          * We need to do this as IF_ADDR_LOCK() may be re-acquired
  970          * by code further down.
  971          */
  972         IF_ADDR_RLOCK(ifp);
  973         TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
  974                 if (ifma->ifma_addr->sa_family != AF_INET6 ||
  975                     ifma->ifma_protospec == NULL)
  976                         continue;
  977                 inm = (struct in6_multi *)ifma->ifma_protospec;
  978                 LIST_INSERT_HEAD(&purgeinms, inm, in6m_entry);
  979         }
  980         IF_ADDR_RUNLOCK(ifp);
  981 
  982         LIST_FOREACH_SAFE(inm, &purgeinms, in6m_entry, tinm) {
  983                 LIST_REMOVE(inm, in6m_entry);
  984                 in6m_release_locked(inm);
  985         }
  986         mld_ifdetach(ifp);
  987 
  988         IN6_MULTI_UNLOCK();
  989 }

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