The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netinet6/nd6_rtr.c

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    1 /*      $NetBSD: nd6_rtr.c,v 1.47 2003/12/10 11:46:33 itojun Exp $      */
    2 /*      $KAME: nd6_rtr.c,v 1.95 2001/02/07 08:09:47 itojun Exp $        */
    3 
    4 /*
    5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. Neither the name of the project nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  */
   32 
   33 #include <sys/cdefs.h>
   34 __KERNEL_RCSID(0, "$NetBSD: nd6_rtr.c,v 1.47 2003/12/10 11:46:33 itojun Exp $");
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/malloc.h>
   39 #include <sys/mbuf.h>
   40 #include <sys/socket.h>
   41 #include <sys/sockio.h>
   42 #include <sys/time.h>
   43 #include <sys/kernel.h>
   44 #include <sys/errno.h>
   45 #include <sys/ioctl.h>
   46 #include <sys/syslog.h>
   47 
   48 #include <net/if.h>
   49 #include <net/if_types.h>
   50 #include <net/if_dl.h>
   51 #include <net/route.h>
   52 #include <net/radix.h>
   53 
   54 #include <netinet/in.h>
   55 #include <netinet6/in6_var.h>
   56 #include <netinet/ip6.h>
   57 #include <netinet6/ip6_var.h>
   58 #include <netinet6/nd6.h>
   59 #include <netinet/icmp6.h>
   60 
   61 #include <net/net_osdep.h>
   62 
   63 #define SDL(s)  ((struct sockaddr_dl *)s)
   64 
   65 static int rtpref __P((struct nd_defrouter *));
   66 static struct nd_defrouter *defrtrlist_update __P((struct nd_defrouter *));
   67 static struct in6_ifaddr *in6_ifadd __P((struct nd_prefix *));
   68 static struct nd_pfxrouter *pfxrtr_lookup __P((struct nd_prefix *,
   69         struct nd_defrouter *));
   70 static void pfxrtr_add __P((struct nd_prefix *, struct nd_defrouter *));
   71 static void pfxrtr_del __P((struct nd_pfxrouter *));
   72 static struct nd_pfxrouter *find_pfxlist_reachable_router
   73         __P((struct nd_prefix *));
   74 static void defrouter_delreq __P((struct nd_defrouter *));
   75 static void defrouter_addifreq __P((struct ifnet *));
   76 static void defrouter_delifreq __P((void));
   77 static void nd6_rtmsg __P((int, struct rtentry *));
   78 
   79 static void in6_init_address_ltimes __P((struct nd_prefix *ndpr,
   80         struct in6_addrlifetime *lt6));
   81 
   82 static int rt6_deleteroute __P((struct radix_node *, void *));
   83 
   84 extern int nd6_recalc_reachtm_interval;
   85 
   86 static struct ifnet *nd6_defifp;
   87 int nd6_defifindex;
   88 static struct ifaddr *nd6_defif_installed = NULL;
   89 
   90 /*
   91  * Receive Router Solicitation Message - just for routers.
   92  * Router solicitation/advertisement is mostly managed by userland program
   93  * (rtadvd) so here we have no function like nd6_ra_output().
   94  *
   95  * Based on RFC 2461
   96  */
   97 void
   98 nd6_rs_input(m, off, icmp6len)
   99         struct  mbuf *m;
  100         int off, icmp6len;
  101 {
  102         struct ifnet *ifp = m->m_pkthdr.rcvif;
  103         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  104         struct nd_router_solicit *nd_rs;
  105         struct in6_addr saddr6 = ip6->ip6_src;
  106 #if 0
  107         struct in6_addr daddr6 = ip6->ip6_dst;
  108 #endif
  109         char *lladdr = NULL;
  110         int lladdrlen = 0;
  111 #if 0
  112         struct sockaddr_dl *sdl = (struct sockaddr_dl *)NULL;
  113         struct llinfo_nd6 *ln = (struct llinfo_nd6 *)NULL;
  114         struct rtentry *rt = NULL;
  115         int is_newentry;
  116 #endif
  117         union nd_opts ndopts;
  118 
  119         /* If I'm not a router, ignore it. */
  120         if (ip6_accept_rtadv != 0 || !ip6_forwarding)
  121                 goto freeit;
  122 
  123         /* Sanity checks */
  124         if (ip6->ip6_hlim != 255) {
  125                 nd6log((LOG_ERR,
  126                     "nd6_rs_input: invalid hlim (%d) from %s to %s on %s\n",
  127                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  128                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  129                 goto bad;
  130         }
  131 
  132         /*
  133          * Don't update the neighbor cache, if src = ::.
  134          * This indicates that the src has no IP address assigned yet.
  135          */
  136         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  137                 goto freeit;
  138 
  139         IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
  140         if (nd_rs == NULL) {
  141                 icmp6stat.icp6s_tooshort++;
  142                 return;
  143         }
  144 
  145         icmp6len -= sizeof(*nd_rs);
  146         nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
  147         if (nd6_options(&ndopts) < 0) {
  148                 nd6log((LOG_INFO,
  149                     "nd6_rs_input: invalid ND option, ignored\n"));
  150                 /* nd6_options have incremented stats */
  151                 goto freeit;
  152         }
  153 
  154         if (ndopts.nd_opts_src_lladdr) {
  155                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  156                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  157         }
  158 
  159         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  160                 nd6log((LOG_INFO,
  161                     "nd6_rs_input: lladdrlen mismatch for %s "
  162                     "(if %d, RS packet %d)\n",
  163                     ip6_sprintf(&saddr6), ifp->if_addrlen, lladdrlen - 2));
  164                 goto bad;
  165         }
  166 
  167         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
  168 
  169  freeit:
  170         m_freem(m);
  171         return;
  172 
  173  bad:
  174         icmp6stat.icp6s_badrs++;
  175         m_freem(m);
  176 }
  177 
  178 /*
  179  * Receive Router Advertisement Message.
  180  *
  181  * Based on RFC 2461
  182  * TODO: on-link bit on prefix information
  183  * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
  184  */
  185 void
  186 nd6_ra_input(m, off, icmp6len)
  187         struct  mbuf *m;
  188         int off, icmp6len;
  189 {
  190         struct ifnet *ifp = m->m_pkthdr.rcvif;
  191         struct nd_ifinfo *ndi = ND_IFINFO(ifp);
  192         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  193         struct nd_router_advert *nd_ra;
  194         struct in6_addr saddr6 = ip6->ip6_src;
  195 #if 0
  196         struct in6_addr daddr6 = ip6->ip6_dst;
  197         int flags; /* = nd_ra->nd_ra_flags_reserved; */
  198         int is_managed = ((flags & ND_RA_FLAG_MANAGED) != 0);
  199         int is_other = ((flags & ND_RA_FLAG_OTHER) != 0);
  200 #endif
  201         union nd_opts ndopts;
  202         struct nd_defrouter *dr;
  203 
  204         /*
  205          * We only accept RAs only when
  206          * the system-wide variable allows the acceptance, and
  207          * per-interface variable allows RAs on the receiving interface.
  208          */
  209         if (ip6_accept_rtadv == 0)
  210                 goto freeit;
  211         if (!(ndi->flags & ND6_IFF_ACCEPT_RTADV))
  212                 goto freeit;
  213 
  214         if (ip6->ip6_hlim != 255) {
  215                 nd6log((LOG_ERR,
  216                     "nd6_ra_input: invalid hlim (%d) from %s to %s on %s\n",
  217                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  218                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  219                 goto bad;
  220         }
  221 
  222         if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
  223                 nd6log((LOG_ERR,
  224                     "nd6_ra_input: src %s is not link-local\n",
  225                     ip6_sprintf(&saddr6)));
  226                 goto bad;
  227         }
  228 
  229         IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
  230         if (nd_ra == NULL) {
  231                 icmp6stat.icp6s_tooshort++;
  232                 return;
  233         }
  234 
  235         icmp6len -= sizeof(*nd_ra);
  236         nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
  237         if (nd6_options(&ndopts) < 0) {
  238                 nd6log((LOG_INFO,
  239                     "nd6_ra_input: invalid ND option, ignored\n"));
  240                 /* nd6_options have incremented stats */
  241                 goto freeit;
  242         }
  243 
  244     {
  245         struct nd_defrouter dr0;
  246         u_int32_t advreachable = nd_ra->nd_ra_reachable;
  247 
  248         Bzero(&dr0, sizeof(dr0));
  249         dr0.rtaddr = saddr6;
  250         dr0.flags  = nd_ra->nd_ra_flags_reserved;
  251         dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
  252         dr0.expire = time.tv_sec + dr0.rtlifetime;
  253         dr0.ifp = ifp;
  254         /* unspecified or not? (RFC 2461 6.3.4) */
  255         if (advreachable) {
  256                 NTOHL(advreachable);
  257                 if (advreachable <= MAX_REACHABLE_TIME &&
  258                     ndi->basereachable != advreachable) {
  259                         ndi->basereachable = advreachable;
  260                         ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
  261                         ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
  262                 }
  263         }
  264         if (nd_ra->nd_ra_retransmit)
  265                 ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
  266         if (nd_ra->nd_ra_curhoplimit)
  267                 ndi->chlim = nd_ra->nd_ra_curhoplimit;
  268         dr = defrtrlist_update(&dr0);
  269     }
  270 
  271         /*
  272          * prefix
  273          */
  274         if (ndopts.nd_opts_pi) {
  275                 struct nd_opt_hdr *pt;
  276                 struct nd_opt_prefix_info *pi = NULL;
  277                 struct nd_prefix pr;
  278 
  279                 for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
  280                      pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
  281                      pt = (struct nd_opt_hdr *)((caddr_t)pt +
  282                                                 (pt->nd_opt_len << 3))) {
  283                         if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
  284                                 continue;
  285                         pi = (struct nd_opt_prefix_info *)pt;
  286 
  287                         if (pi->nd_opt_pi_len != 4) {
  288                                 nd6log((LOG_INFO,
  289                                     "nd6_ra_input: invalid option "
  290                                     "len %d for prefix information option, "
  291                                     "ignored\n", pi->nd_opt_pi_len));
  292                                 continue;
  293                         }
  294 
  295                         if (128 < pi->nd_opt_pi_prefix_len) {
  296                                 nd6log((LOG_INFO,
  297                                     "nd6_ra_input: invalid prefix "
  298                                     "len %d for prefix information option, "
  299                                     "ignored\n", pi->nd_opt_pi_prefix_len));
  300                                 continue;
  301                         }
  302 
  303                         if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
  304                          || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
  305                                 nd6log((LOG_INFO,
  306                                     "nd6_ra_input: invalid prefix "
  307                                     "%s, ignored\n",
  308                                     ip6_sprintf(&pi->nd_opt_pi_prefix)));
  309                                 continue;
  310                         }
  311 
  312                         /* aggregatable unicast address, rfc2374 */
  313                         if ((pi->nd_opt_pi_prefix.s6_addr8[0] & 0xe0) == 0x20
  314                          && pi->nd_opt_pi_prefix_len != 64) {
  315                                 nd6log((LOG_INFO,
  316                                     "nd6_ra_input: invalid prefixlen "
  317                                     "%d for rfc2374 prefix %s, ignored\n",
  318                                     pi->nd_opt_pi_prefix_len,
  319                                     ip6_sprintf(&pi->nd_opt_pi_prefix)));
  320                                 continue;
  321                         }
  322 
  323                         bzero(&pr, sizeof(pr));
  324                         pr.ndpr_prefix.sin6_family = AF_INET6;
  325                         pr.ndpr_prefix.sin6_len = sizeof(pr.ndpr_prefix);
  326                         pr.ndpr_prefix.sin6_addr = pi->nd_opt_pi_prefix;
  327                         pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;
  328 
  329                         pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
  330                              ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
  331                         pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
  332                              ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
  333                         pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
  334                         pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
  335                         pr.ndpr_pltime = ntohl(pi->nd_opt_pi_preferred_time);
  336                         pr.ndpr_lastupdate = time.tv_sec;
  337 
  338                         if (in6_init_prefix_ltimes(&pr))
  339                                 continue; /* prefix lifetime init failed */
  340 
  341                         (void)prelist_update(&pr, dr, m);
  342                 }
  343         }
  344 
  345         /*
  346          * MTU
  347          */
  348         if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
  349                 u_long mtu;
  350                 u_long maxmtu;
  351 
  352                 mtu = ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
  353 
  354                 /* lower bound */
  355                 if (mtu < IPV6_MMTU) {
  356                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
  357                             "mtu=%lu sent from %s, ignoring\n",
  358                             mtu, ip6_sprintf(&ip6->ip6_src)));
  359                         goto skip;
  360                 }
  361 
  362                 /* upper bound */
  363                 maxmtu = (ndi->maxmtu && ndi->maxmtu < ifp->if_mtu)
  364                     ? ndi->maxmtu : ifp->if_mtu;
  365                 if (mtu <= maxmtu) {
  366                         int change = (ndi->linkmtu != mtu);
  367 
  368                         ndi->linkmtu = mtu;
  369                         if (change) /* in6_maxmtu may change */
  370                                 in6_setmaxmtu();
  371                 } else {
  372                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
  373                             "mtu=%lu sent from %s; "
  374                             "exceeds maxmtu %lu, ignoring\n",
  375                             mtu, ip6_sprintf(&ip6->ip6_src), maxmtu));
  376                 }
  377         }
  378 
  379  skip:
  380 
  381         /*
  382          * Source link layer address
  383          */
  384     {
  385         char *lladdr = NULL;
  386         int lladdrlen = 0;
  387 
  388         if (ndopts.nd_opts_src_lladdr) {
  389                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  390                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  391         }
  392 
  393         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  394                 nd6log((LOG_INFO,
  395                     "nd6_ra_input: lladdrlen mismatch for %s "
  396                     "(if %d, RA packet %d)\n", ip6_sprintf(&saddr6),
  397                     ifp->if_addrlen, lladdrlen - 2));
  398                 goto bad;
  399         }
  400 
  401         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_ADVERT, 0);
  402 
  403         /*
  404          * Installing a link-layer address might change the state of the
  405          * router's neighbor cache, which might also affect our on-link
  406          * detection of adveritsed prefixes.
  407          */
  408         pfxlist_onlink_check();
  409     }
  410 
  411  freeit:
  412         m_freem(m);
  413         return;
  414 
  415  bad:
  416         icmp6stat.icp6s_badra++;
  417         m_freem(m);
  418 }
  419 
  420 /*
  421  * default router list processing sub routines
  422  */
  423 
  424 /* tell the change to user processes watching the routing socket. */
  425 static void
  426 nd6_rtmsg(cmd, rt)
  427         int cmd;
  428         struct rtentry *rt;
  429 {
  430         struct rt_addrinfo info;
  431 
  432         bzero((caddr_t)&info, sizeof(info));
  433         info.rti_info[RTAX_DST] = rt_key(rt);
  434         info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
  435         info.rti_info[RTAX_NETMASK] = rt_mask(rt);
  436         if (rt->rt_ifp) {
  437                 info.rti_info[RTAX_IFP] =
  438                     TAILQ_FIRST(&rt->rt_ifp->if_addrlist)->ifa_addr;
  439                 info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
  440         }
  441 
  442         rt_missmsg(cmd, &info, rt->rt_flags, 0);
  443 }
  444 
  445 void
  446 defrouter_addreq(new)
  447         struct nd_defrouter *new;
  448 {
  449         struct sockaddr_in6 def, mask, gate;
  450         struct rtentry *newrt = NULL;
  451         int s;
  452         int error;
  453 
  454         Bzero(&def, sizeof(def));
  455         Bzero(&mask, sizeof(mask));
  456         Bzero(&gate, sizeof(gate)); /* for safety */
  457 
  458         def.sin6_len = mask.sin6_len = gate.sin6_len =
  459             sizeof(struct sockaddr_in6);
  460         def.sin6_family = mask.sin6_family = gate.sin6_family = AF_INET6;
  461         gate.sin6_addr = new->rtaddr;
  462 #ifndef SCOPEDROUTING
  463         gate.sin6_scope_id = 0; /* XXX */
  464 #endif
  465 
  466         s = splsoftnet();
  467         error = rtrequest(RTM_ADD, (struct sockaddr *)&def,
  468             (struct sockaddr *)&gate, (struct sockaddr *)&mask,
  469             RTF_GATEWAY, &newrt);
  470         if (newrt) {
  471                 nd6_rtmsg(RTM_ADD, newrt); /* tell user process */
  472                 newrt->rt_refcnt--;
  473         }
  474         if (error == 0)
  475                 new->installed = 1;
  476         splx(s);
  477         return;
  478 }
  479 
  480 /* Add a route to a given interface as default */
  481 static void
  482 defrouter_addifreq(ifp)
  483         struct ifnet *ifp;
  484 {
  485         struct sockaddr_in6 def, mask;
  486         struct ifaddr *ifa;
  487         struct rtentry *newrt = NULL;
  488         int error, flags;
  489         struct rt_addrinfo info;
  490 
  491         /* remove one if we have already installed one */
  492         if (nd6_defif_installed)
  493                 defrouter_delifreq();
  494 
  495         bzero(&def, sizeof(def));
  496         bzero(&mask, sizeof(mask));
  497 
  498         def.sin6_len = mask.sin6_len = sizeof(struct sockaddr_in6);
  499         def.sin6_family = mask.sin6_family = AF_INET6;
  500 
  501         /*
  502          * Search for an ifaddr beloging to the specified interface.
  503          * XXX: An IPv6 address are required to be assigned on the interface.
  504          */
  505         if ((ifa = ifaof_ifpforaddr((struct sockaddr *)&def, ifp)) == NULL) {
  506                 nd6log((LOG_ERR,        /* better error? */
  507                     "defrouter_addifreq: failed to find an ifaddr "
  508                     "to install a route to interface %s\n",
  509                     if_name(ifp)));
  510                 return;
  511         }
  512 
  513         /* RTF_CLONING is necessary to make sure to perform ND */
  514         flags = ifa->ifa_flags | RTF_CLONING;
  515         bzero(&info, sizeof(info));
  516         info.rti_info[RTAX_DST] = (struct sockaddr *)&def;
  517         info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)ifa->ifa_addr;
  518         info.rti_info[RTAX_NETMASK] = (struct sockaddr *)&mask;
  519         info.rti_info[RTAX_IFA] = (struct sockaddr *)ifa->ifa_addr;
  520         info.rti_flags = flags;
  521         error = rtrequest1(RTM_ADD, &info, &newrt);
  522         if (error != 0) {
  523                 nd6log((LOG_ERR,
  524                     "defrouter_addifreq: failed to install a route to "
  525                     "interface %s (errno = %d)\n",
  526                     if_name(ifp), error));
  527 
  528                 if (newrt)      /* maybe unnecessary, but do it for safety */
  529                         newrt->rt_refcnt--;
  530         } else {
  531                 if (newrt) {
  532                         nd6_rtmsg(RTM_ADD, newrt);
  533                         newrt->rt_refcnt--;
  534                 }
  535         }
  536 
  537         nd6_defif_installed = ifa;
  538         IFAREF(ifa);
  539 }
  540 
  541 /* Remove a default route points to interface */
  542 static void
  543 defrouter_delifreq()
  544 {
  545         struct sockaddr_in6 def, mask;
  546         struct rtentry *oldrt = NULL;
  547 
  548         if (!nd6_defif_installed)
  549                 return;
  550 
  551         Bzero(&def, sizeof(def));
  552         Bzero(&mask, sizeof(mask));
  553 
  554         def.sin6_len = mask.sin6_len = sizeof(struct sockaddr_in6);
  555         def.sin6_family = mask.sin6_family = AF_INET6;
  556 
  557         rtrequest(RTM_DELETE, (struct sockaddr *)&def,
  558             (struct sockaddr *)nd6_defif_installed->ifa_addr,
  559             (struct sockaddr *)&mask, RTF_GATEWAY, &oldrt);
  560         if (oldrt) {
  561                 nd6_rtmsg(RTM_DELETE, oldrt);
  562                 if (oldrt->rt_refcnt <= 0) {
  563                         /*
  564                          * XXX: borrowed from the RTM_DELETE case of
  565                          * rtrequest().
  566                          */
  567                         oldrt->rt_refcnt++;
  568                         rtfree(oldrt);
  569                 }
  570         }
  571 
  572         IFAFREE(nd6_defif_installed);
  573         nd6_defif_installed = NULL;
  574 }
  575 
  576 struct nd_defrouter *
  577 defrouter_lookup(addr, ifp)
  578         struct in6_addr *addr;
  579         struct ifnet *ifp;
  580 {
  581         struct nd_defrouter *dr;
  582 
  583         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  584              dr = TAILQ_NEXT(dr, dr_entry)) {
  585                 if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr)) {
  586                         return (dr);
  587                 }
  588         }
  589 
  590         return (NULL);          /* search failed */
  591 }
  592 
  593 void
  594 defrtrlist_del(dr)
  595         struct nd_defrouter *dr;
  596 {
  597         struct nd_defrouter *deldr = NULL;
  598         struct nd_prefix *pr;
  599 
  600         /*
  601          * Flush all the routing table entries that use the router
  602          * as a next hop.
  603          */
  604         if (!ip6_forwarding && ip6_accept_rtadv) /* XXX: better condition? */
  605                 rt6_flush(&dr->rtaddr, dr->ifp);
  606 
  607         if (dr->installed) {
  608                 deldr = dr;
  609                 defrouter_delreq(dr);
  610         }
  611         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  612 
  613         /*
  614          * Also delete all the pointers to the router in each prefix lists.
  615          */
  616         for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
  617                 struct nd_pfxrouter *pfxrtr;
  618                 if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
  619                         pfxrtr_del(pfxrtr);
  620         }
  621         pfxlist_onlink_check();
  622 
  623         /*
  624          * If the router is the primary one, choose a new one.
  625          * Note that defrouter_select() will remove the current gateway
  626          * from the routing table.
  627          */
  628         if (deldr)
  629                 defrouter_select();
  630 
  631         free(dr, M_IP6NDP);
  632 }
  633 
  634 /*
  635  * Remove the default route for a given router.
  636  * This is just a subroutine function for defrouter_select(), and should
  637  * not be called from anywhere else.
  638  */
  639 static void
  640 defrouter_delreq(dr)
  641         struct nd_defrouter *dr;
  642 {
  643         struct sockaddr_in6 def, mask, gw;
  644         struct rtentry *oldrt = NULL;
  645 
  646 #ifdef DIAGNOSTIC
  647         if (!dr)
  648                 panic("dr == NULL in defrouter_delreq");
  649 #endif
  650 
  651         Bzero(&def, sizeof(def));
  652         Bzero(&mask, sizeof(mask));
  653         Bzero(&gw, sizeof(gw)); /* for safety */
  654 
  655         def.sin6_len = mask.sin6_len = gw.sin6_len =
  656             sizeof(struct sockaddr_in6);
  657         def.sin6_family = mask.sin6_family = gw.sin6_family = AF_INET6;
  658         gw.sin6_addr = dr->rtaddr;
  659 #ifndef SCOPEDROUTING
  660         gw.sin6_scope_id = 0;   /* XXX */
  661 #endif
  662 
  663         rtrequest(RTM_DELETE, (struct sockaddr *)&def,
  664             (struct sockaddr *)&gw,
  665             (struct sockaddr *)&mask, RTF_GATEWAY, &oldrt);
  666         if (oldrt) {
  667                 nd6_rtmsg(RTM_DELETE, oldrt);
  668                 if (oldrt->rt_refcnt <= 0) {
  669                         /*
  670                          * XXX: borrowed from the RTM_DELETE case of
  671                          * rtrequest().
  672                          */
  673                         oldrt->rt_refcnt++;
  674                         rtfree(oldrt);
  675                 }
  676         }
  677 
  678         dr->installed = 0;
  679 }
  680 
  681 /*
  682  * remove all default routes from default router list
  683  */
  684 void
  685 defrouter_reset()
  686 {
  687         struct nd_defrouter *dr;
  688 
  689         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  690              dr = TAILQ_NEXT(dr, dr_entry))
  691                 defrouter_delreq(dr);
  692         defrouter_delifreq();
  693 
  694         /*
  695          * XXX should we also nuke any default routers in the kernel, by
  696          * going through them by rtalloc1()?
  697          */
  698 }
  699 
  700 /*
  701  * Default Router Selection according to Section 6.3.6 of RFC 2461 and
  702  * draft-ietf-ipngwg-router-selection:
  703  * 1) Routers that are reachable or probably reachable should be preferred.
  704  *    If we have more than one (probably) reachable router, prefer ones
  705  *    with the highest router preference.
  706  * 2) When no routers on the list are known to be reachable or
  707  *    probably reachable, routers SHOULD be selected in a round-robin
  708  *    fashion, regardless of router preference values.
  709  * 3) If the Default Router List is empty, assume that all
  710  *    destinations are on-link.
  711  *
  712  * We assume nd_defrouter is sorted by router preference value.
  713  * Since the code below covers both with and without router preference cases,
  714  * we do not need to classify the cases by ifdef.
  715  *
  716  * At this moment, we do not try to install more than one default router,
  717  * even when the multipath routing is available, because we're not sure about
  718  * the benefits for stub hosts comparing to the risk of making the code
  719  * complicated and the possibility of introducing bugs.
  720  */
  721 void
  722 defrouter_select()
  723 {
  724         int s = splsoftnet();
  725         struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
  726         struct rtentry *rt = NULL;
  727         struct llinfo_nd6 *ln = NULL;
  728 
  729         /*
  730          * This function should be called only when acting as an autoconfigured
  731          * host.  Although the remaining part of this function is not effective
  732          * if the node is not an autoconfigured host, we explicitly exclude
  733          * such cases here for safety.
  734          */
  735         if (ip6_forwarding || !ip6_accept_rtadv) {
  736                 nd6log((LOG_WARNING,
  737                     "defrouter_select: called unexpectedly (forwarding=%d, "
  738                     "accept_rtadv=%d)\n", ip6_forwarding, ip6_accept_rtadv));
  739                 splx(s);
  740                 return;
  741         }
  742 
  743         /*
  744          * Let's handle easy case (3) first:
  745          * If default router list is empty, we should probably install
  746          * an interface route and assume that all destinations are on-link.
  747          */
  748         if (!TAILQ_FIRST(&nd_defrouter)) {
  749                 /*
  750                  * XXX: The specification does not say this mechanism should
  751                  * be restricted to hosts, but this would be not useful
  752                  * (even harmful) for routers.
  753                  * This test is meaningless due to a test at the beginning of
  754                  * the function, but we intentionally keep it to make the note
  755                  * clear.
  756                  */
  757                 if (!ip6_forwarding) {
  758                         if (nd6_defifp) {
  759                                 /*
  760                                  * Install a route to the default interface
  761                                  * as default route.
  762                                  */
  763                                 defrouter_addifreq(nd6_defifp);
  764                         } else {
  765                                 /*
  766                                  * purge the existing route.
  767                                  * XXX: is this really correct?
  768                                  */
  769                                 defrouter_delifreq();
  770                                 nd6log((LOG_INFO, "defrouter_select: "
  771                                     "there's no default router and no default"
  772                                     " interface\n"));
  773                         }
  774                 }
  775                 splx(s);
  776                 return;
  777         }
  778 
  779         /*
  780          * If we have a default route for the default interface, delete it.
  781          * Note that the existence of the route is checked in the delete
  782          * function.
  783          */
  784         defrouter_delifreq();
  785 
  786         /*
  787          * Search for a (probably) reachable router from the list.
  788          * We just pick up the first reachable one (if any), assuming that
  789          * the ordering rule of the list described in defrtrlist_update().
  790          */
  791         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  792              dr = TAILQ_NEXT(dr, dr_entry)) {
  793                 if (!selected_dr &&
  794                     (rt = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) &&
  795                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
  796                     ND6_IS_LLINFO_PROBREACH(ln)) {
  797                         selected_dr = dr;
  798                 }
  799 
  800                 if (dr->installed && !installed_dr)
  801                         installed_dr = dr;
  802                 else if (dr->installed && installed_dr) {
  803                         /* this should not happen.  warn for diagnosis. */
  804                         log(LOG_ERR, "defrouter_select: more than one router"
  805                             " is installed\n");
  806                 }
  807         }
  808         /*
  809          * If none of the default routers was found to be reachable,
  810          * round-robin the list regardless of preference.
  811          * Otherwise, if we have an installed router, check if the selected
  812          * (reachable) router should really be preferred to the installed one.
  813          * We only prefer the new router when the old one is not reachable
  814          * or when the new one has a really higher preference value.
  815          */
  816         if (!selected_dr) {
  817                 if (!installed_dr || !TAILQ_NEXT(installed_dr, dr_entry))
  818                         selected_dr = TAILQ_FIRST(&nd_defrouter);
  819                 else
  820                         selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
  821         } else if (installed_dr &&
  822             (rt = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp)) &&
  823             (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
  824             ND6_IS_LLINFO_PROBREACH(ln) &&
  825             rtpref(selected_dr) <= rtpref(installed_dr)) {
  826                 selected_dr = installed_dr;
  827         }
  828 
  829         /*
  830          * If the selected router is different than the installed one,
  831          * remove the installed router and install the selected one.
  832          * Note that the selected router is never NULL here.
  833          */
  834         if (installed_dr != selected_dr) {
  835                 if (installed_dr)
  836                         defrouter_delreq(installed_dr);
  837                 defrouter_addreq(selected_dr);
  838         }
  839 
  840         splx(s);
  841         return;
  842 }
  843 
  844 /*
  845  * for default router selection
  846  * regards router-preference field as a 2-bit signed integer
  847  */
  848 static int
  849 rtpref(struct nd_defrouter *dr)
  850 {
  851 #ifdef RTPREF
  852         switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
  853         case ND_RA_FLAG_RTPREF_HIGH:
  854                 return RTPREF_HIGH;
  855         case ND_RA_FLAG_RTPREF_MEDIUM:
  856         case ND_RA_FLAG_RTPREF_RSV:
  857                 return RTPREF_MEDIUM;
  858         case ND_RA_FLAG_RTPREF_LOW:
  859                 return RTPREF_LOW;
  860         default:
  861                 /*
  862                  * This case should never happen.  If it did, it would mean a
  863                  * serious bug of kernel internal.  We thus always bark here.
  864                  * Or, can we even panic?
  865                  */
  866                 log(LOG_ERR, "rtpref: impossible RA flag %x", dr->flags);
  867                 return RTPREF_INVALID;
  868         }
  869         /* NOTREACHED */
  870 #else
  871         return 0;
  872 #endif
  873 }
  874 
  875 static struct nd_defrouter *
  876 defrtrlist_update(new)
  877         struct nd_defrouter *new;
  878 {
  879         struct nd_defrouter *dr, *n;
  880         int s = splsoftnet();
  881 
  882         if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
  883                 /* entry exists */
  884                 if (new->rtlifetime == 0) {
  885                         defrtrlist_del(dr);
  886                         dr = NULL;
  887                 } else {
  888                         int oldpref = rtpref(dr);
  889 
  890                         /* override */
  891                         dr->flags = new->flags; /* xxx flag check */
  892                         dr->rtlifetime = new->rtlifetime;
  893                         dr->expire = new->expire;
  894 
  895                         /*
  896                          * If the preference does not change, there's no need
  897                          * to sort the entries.
  898                          */
  899                         if (rtpref(new) == oldpref) {
  900                                 splx(s);
  901                                 return (dr);
  902                         }
  903 
  904                         /*
  905                          * preferred router may be changed, so relocate
  906                          * this router.
  907                          * XXX: calling TAILQ_REMOVE directly is a bad manner.
  908                          * However, since defrtrlist_del() has many side
  909                          * effects, we intentionally do so here.
  910                          * defrouter_select() below will handle routing
  911                          * changes later.
  912                          */
  913                         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  914                         n = dr;
  915                         goto insert;
  916                 }
  917                 splx(s);
  918                 return (dr);
  919         }
  920 
  921         /* entry does not exist */
  922         if (new->rtlifetime == 0) {
  923                 splx(s);
  924                 return (NULL);
  925         }
  926 
  927         n = (struct nd_defrouter *)malloc(sizeof(*n), M_IP6NDP, M_NOWAIT);
  928         if (n == NULL) {
  929                 splx(s);
  930                 return (NULL);
  931         }
  932         bzero(n, sizeof(*n));
  933         *n = *new;
  934 
  935 insert:
  936         /*
  937          * Insert the new router in the Default Router List;
  938          * The Default Router List should be in the descending order
  939          * of router-preferece.  Routers with the same preference are
  940          * sorted in the arriving time order.
  941          */
  942 
  943         /* insert at the end of the group */
  944         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  945              dr = TAILQ_NEXT(dr, dr_entry)) {
  946                 if (rtpref(n) > rtpref(dr))
  947                         break;
  948         }
  949         if (dr)
  950                 TAILQ_INSERT_BEFORE(dr, n, dr_entry);
  951         else
  952                 TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);
  953 
  954         defrouter_select();
  955 
  956         splx(s);
  957 
  958         return (n);
  959 }
  960 
  961 static struct nd_pfxrouter *
  962 pfxrtr_lookup(pr, dr)
  963         struct nd_prefix *pr;
  964         struct nd_defrouter *dr;
  965 {
  966         struct nd_pfxrouter *search;
  967 
  968         for (search = pr->ndpr_advrtrs.lh_first; search; search = search->pfr_next) {
  969                 if (search->router == dr)
  970                         break;
  971         }
  972 
  973         return (search);
  974 }
  975 
  976 static void
  977 pfxrtr_add(pr, dr)
  978         struct nd_prefix *pr;
  979         struct nd_defrouter *dr;
  980 {
  981         struct nd_pfxrouter *new;
  982 
  983         new = (struct nd_pfxrouter *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  984         if (new == NULL)
  985                 return;
  986         bzero(new, sizeof(*new));
  987         new->router = dr;
  988 
  989         LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
  990 
  991         pfxlist_onlink_check();
  992 }
  993 
  994 static void
  995 pfxrtr_del(pfr)
  996         struct nd_pfxrouter *pfr;
  997 {
  998         LIST_REMOVE(pfr, pfr_entry);
  999         free(pfr, M_IP6NDP);
 1000 }
 1001 
 1002 struct nd_prefix *
 1003 nd6_prefix_lookup(pr)
 1004         struct nd_prefix *pr;
 1005 {
 1006         struct nd_prefix *search;
 1007 
 1008         for (search = nd_prefix.lh_first; search; search = search->ndpr_next) {
 1009                 if (pr->ndpr_ifp == search->ndpr_ifp &&
 1010                     pr->ndpr_plen == search->ndpr_plen &&
 1011                     in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1012                     &search->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
 1013                         break;
 1014                 }
 1015         }
 1016 
 1017         return (search);
 1018 }
 1019 
 1020 int
 1021 nd6_prelist_add(pr, dr, newp)
 1022         struct nd_prefix *pr, **newp;
 1023         struct nd_defrouter *dr;
 1024 {
 1025         struct nd_prefix *new = NULL;
 1026         int i, s;
 1027 
 1028         new = (struct nd_prefix *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
 1029         if (new == NULL)
 1030                 return ENOMEM;
 1031         bzero(new, sizeof(*new));
 1032         *new = *pr;
 1033         if (newp != NULL)
 1034                 *newp = new;
 1035 
 1036         /* initilization */
 1037         LIST_INIT(&new->ndpr_advrtrs);
 1038         in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
 1039         /* make prefix in the canonical form */
 1040         for (i = 0; i < 4; i++)
 1041                 new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
 1042                     new->ndpr_mask.s6_addr32[i];
 1043 
 1044         s = splsoftnet();
 1045         /* link ndpr_entry to nd_prefix list */
 1046         LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
 1047         splx(s);
 1048 
 1049         /* ND_OPT_PI_FLAG_ONLINK processing */
 1050         if (new->ndpr_raf_onlink) {
 1051                 int e;
 1052 
 1053                 if ((e = nd6_prefix_onlink(new)) != 0) {
 1054                         nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
 1055                             "the prefix %s/%d on-link on %s (errno=%d)\n",
 1056                             ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1057                             pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
 1058                         /* proceed anyway. XXX: is it correct? */
 1059                 }
 1060         }
 1061 
 1062         if (dr)
 1063                 pfxrtr_add(new, dr);
 1064 
 1065         return 0;
 1066 }
 1067 
 1068 void
 1069 prelist_remove(pr)
 1070         struct nd_prefix *pr;
 1071 {
 1072         struct nd_pfxrouter *pfr, *next;
 1073         int e, s;
 1074 
 1075         /* make sure to invalidate the prefix until it is really freed. */
 1076         pr->ndpr_vltime = 0;
 1077         pr->ndpr_pltime = 0;
 1078 #if 0
 1079         /*
 1080          * Though these flags are now meaningless, we'd rather keep the value
 1081          * not to confuse users when executing "ndp -p".
 1082          */
 1083         pr->ndpr_raf_onlink = 0;
 1084         pr->ndpr_raf_auto = 0;
 1085 #endif
 1086         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
 1087             (e = nd6_prefix_offlink(pr)) != 0) {
 1088                 nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
 1089                     "on %s, errno=%d\n",
 1090                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1091                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
 1092                 /* what should we do? */
 1093         }
 1094 
 1095         if (pr->ndpr_refcnt > 0)
 1096                 return;         /* notice here? */
 1097 
 1098         s = splsoftnet();
 1099         /* unlink ndpr_entry from nd_prefix list */
 1100         LIST_REMOVE(pr, ndpr_entry);
 1101 
 1102         /* free list of routers that adversed the prefix */
 1103         for (pfr = pr->ndpr_advrtrs.lh_first; pfr; pfr = next) {
 1104                 next = pfr->pfr_next;
 1105 
 1106                 free(pfr, M_IP6NDP);
 1107         }
 1108         splx(s);
 1109 
 1110         free(pr, M_IP6NDP);
 1111 
 1112         pfxlist_onlink_check();
 1113 }
 1114 
 1115 int
 1116 prelist_update(new, dr, m)
 1117         struct nd_prefix *new;
 1118         struct nd_defrouter *dr; /* may be NULL */
 1119         struct mbuf *m;
 1120 {
 1121         struct in6_ifaddr *ia6 = NULL, *ia6_match = NULL;
 1122         struct ifaddr *ifa;
 1123         struct ifnet *ifp = new->ndpr_ifp;
 1124         struct nd_prefix *pr;
 1125         int s = splsoftnet();
 1126         int error = 0;
 1127         int auth;
 1128         struct in6_addrlifetime lt6_tmp;
 1129 
 1130         auth = 0;
 1131         if (m) {
 1132                 /*
 1133                  * Authenticity for NA consists authentication for
 1134                  * both IP header and IP datagrams, doesn't it ?
 1135                  */
 1136 #if defined(M_AUTHIPHDR) && defined(M_AUTHIPDGM)
 1137                 auth = (m->m_flags & M_AUTHIPHDR
 1138                      && m->m_flags & M_AUTHIPDGM) ? 1 : 0;
 1139 #endif
 1140         }
 1141 
 1142         if ((pr = nd6_prefix_lookup(new)) != NULL) {
 1143                 /*
 1144                  * nd6_prefix_lookup() ensures that pr and new have the same
 1145                  * prefix on a same interface.
 1146                  */
 1147 
 1148                 /*
 1149                  * Update prefix information.  Note that the on-link (L) bit
 1150                  * and the autonomous (A) bit should NOT be changed from 1
 1151                  * to 0.
 1152                  */
 1153                 if (new->ndpr_raf_onlink == 1)
 1154                         pr->ndpr_raf_onlink = 1;
 1155                 if (new->ndpr_raf_auto == 1)
 1156                         pr->ndpr_raf_auto = 1;
 1157                 if (new->ndpr_raf_onlink) {
 1158                         pr->ndpr_vltime = new->ndpr_vltime;
 1159                         pr->ndpr_pltime = new->ndpr_pltime;
 1160                         pr->ndpr_preferred = new->ndpr_preferred;
 1161                         pr->ndpr_expire = new->ndpr_expire;
 1162                         pr->ndpr_lastupdate = new->ndpr_lastupdate;
 1163                 }
 1164 
 1165                 if (new->ndpr_raf_onlink &&
 1166                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1167                         int e;
 1168 
 1169                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1170                                 nd6log((LOG_ERR,
 1171                                     "prelist_update: failed to make "
 1172                                     "the prefix %s/%d on-link on %s "
 1173                                     "(errno=%d)\n",
 1174                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1175                                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
 1176                                 /* proceed anyway. XXX: is it correct? */
 1177                         }
 1178                 }
 1179 
 1180                 if (dr && pfxrtr_lookup(pr, dr) == NULL)
 1181                         pfxrtr_add(pr, dr);
 1182         } else {
 1183                 struct nd_prefix *newpr = NULL;
 1184 
 1185                 if (new->ndpr_vltime == 0)
 1186                         goto end;
 1187                 if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
 1188                         goto end;
 1189 
 1190                 error = nd6_prelist_add(new, dr, &newpr);
 1191                 if (error != 0 || newpr == NULL) {
 1192                         nd6log((LOG_NOTICE, "prelist_update: "
 1193                             "nd6_prelist_add failed for %s/%d on %s "
 1194                             "errno=%d, returnpr=%p\n",
 1195                             ip6_sprintf(&new->ndpr_prefix.sin6_addr),
 1196                             new->ndpr_plen, if_name(new->ndpr_ifp),
 1197                             error, newpr));
 1198                         goto end; /* we should just give up in this case. */
 1199                 }
 1200 
 1201                 /*
 1202                  * XXX: from the ND point of view, we can ignore a prefix
 1203                  * with the on-link bit being zero.  However, we need a
 1204                  * prefix structure for references from autoconfigured
 1205                  * addresses.  Thus, we explicitly make sure that the prefix
 1206                  * itself expires now.
 1207                  */
 1208                 if (newpr->ndpr_raf_onlink == 0) {
 1209                         newpr->ndpr_vltime = 0;
 1210                         newpr->ndpr_pltime = 0;
 1211                         in6_init_prefix_ltimes(newpr);
 1212                 }
 1213 
 1214                 pr = newpr;
 1215         }
 1216 
 1217         /*
 1218          * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
 1219          * Note that pr must be non NULL at this point.
 1220          */
 1221 
 1222         /* 5.5.3 (a). Ignore the prefix without the A bit set. */
 1223         if (!new->ndpr_raf_auto)
 1224                 goto end;
 1225 
 1226         /*
 1227          * 5.5.3 (b). the link-local prefix should have been ignored in
 1228          * nd6_ra_input.
 1229          */
 1230 
 1231         /*
 1232          * 5.5.3 (c). Consistency check on lifetimes: pltime <= vltime.
 1233          * This should have been done in nd6_ra_input.
 1234          */
 1235 
 1236         /*
 1237          * 5.5.3 (d). If the prefix advertised does not match the prefix of an
 1238          * address already in the list, and the Valid Lifetime is not 0,
 1239          * form an address.  Note that even a manually configured address
 1240          * should reject autoconfiguration of a new address.
 1241          */
 1242         for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa->ifa_list.tqe_next)
 1243         {
 1244                 struct in6_ifaddr *ifa6;
 1245                 int ifa_plen;
 1246                 u_int32_t storedlifetime;
 1247 
 1248                 if (ifa->ifa_addr->sa_family != AF_INET6)
 1249                         continue;
 1250 
 1251                 ifa6 = (struct in6_ifaddr *)ifa;
 1252 
 1253                 /*
 1254                  * Spec is not clear here, but I believe we should concentrate
 1255                  * on unicast (i.e. not anycast) addresses.
 1256                  * XXX: other ia6_flags? detached or duplicated?
 1257                  */
 1258                 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0)
 1259                         continue;
 1260 
 1261                 ifa_plen = in6_mask2len(&ifa6->ia_prefixmask.sin6_addr, NULL);
 1262                 if (ifa_plen != new->ndpr_plen ||
 1263                     !in6_are_prefix_equal(&ifa6->ia_addr.sin6_addr,
 1264                     &new->ndpr_prefix.sin6_addr, ifa_plen))
 1265                         continue;
 1266 
 1267                 if (ia6_match == NULL) /* remember the first one */
 1268                         ia6_match = ifa6;
 1269 
 1270                 if ((ifa6->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1271                         continue;
 1272 
 1273                 /*
 1274                  * An already autoconfigured address matched.  Now that we
 1275                  * are sure there is at least one matched address, we can
 1276                  * proceed to 5.5.3. (e): update the lifetimes according to the
 1277                  * "two hours" rule and the privacy extension.
 1278                  */
 1279 #define TWOHOUR         (120*60)
 1280                 /*
 1281                  * RFC2462 introduces the notion of StoredLifetime to the
 1282                  * "two hours" rule as follows:
 1283                  *   the Lifetime associated with the previously autoconfigured
 1284                  *   address.
 1285                  * Our interpretation of this definition is "the remaining
 1286                  * lifetime to expiration at the evaluation time".  One might
 1287                  * be wondering if this interpretation is really conform to the
 1288                  * RFC, because the text can read that "Lifetimes" are never
 1289                  * decreased, and our definition of the "storedlifetime" below
 1290                  * essentially reduces the "Valid Lifetime" advertised in the
 1291                  * previous RA.  But, this is due to the wording of the text,
 1292                  * and our interpretation is the same as an author's intention.
 1293                  * See the discussion in the IETF ipngwg ML in August 2001,
 1294                  * with the Subject "StoredLifetime in RFC 2462".
 1295                  */
 1296                 lt6_tmp = ifa6->ia6_lifetime;
 1297                 if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME)
 1298                         storedlifetime = ND6_INFINITE_LIFETIME;
 1299                 else if (time.tv_sec - ifa6->ia6_updatetime >
 1300                          lt6_tmp.ia6t_vltime) {
 1301                         /*
 1302                          * The case of "invalid" address.  We should usually
 1303                          * not see this case.
 1304                          */
 1305                         storedlifetime = 0;
 1306                 } else
 1307                         storedlifetime = lt6_tmp.ia6t_vltime -
 1308                                 (time.tv_sec - ifa6->ia6_updatetime);
 1309                 if (TWOHOUR < new->ndpr_vltime ||
 1310                     storedlifetime < new->ndpr_vltime) {
 1311                         lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1312                 } else if (storedlifetime <= TWOHOUR
 1313 #if 0
 1314                            /*
 1315                             * This condition is logically redundant, so we just
 1316                             * omit it.
 1317                             * See IPng 6712, 6717, and 6721.
 1318                             */
 1319                            && new->ndpr_vltime <= storedlifetime
 1320 #endif
 1321                         ) {
 1322                         if (auth) {
 1323                                 lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1324                         }
 1325                 } else {
 1326                         /*
 1327                          * new->ndpr_vltime <= TWOHOUR &&
 1328                          * TWOHOUR < storedlifetime
 1329                          */
 1330                         lt6_tmp.ia6t_vltime = TWOHOUR;
 1331                 }
 1332 
 1333                 /* The 2 hour rule is not imposed for preferred lifetime. */
 1334                 lt6_tmp.ia6t_pltime = new->ndpr_pltime;
 1335 
 1336                 in6_init_address_ltimes(pr, &lt6_tmp);
 1337 
 1338                 ifa6->ia6_lifetime = lt6_tmp;
 1339                 ifa6->ia6_updatetime = time.tv_sec;
 1340         }
 1341         if (ia6_match == NULL && new->ndpr_vltime) {
 1342                 /*
 1343                  * No address matched and the valid lifetime is non-zero.
 1344                  * Create a new address.
 1345                  */
 1346                 if ((ia6 = in6_ifadd(new)) != NULL) {
 1347                         /*
 1348                          * note that we should use pr (not new) for reference.
 1349                          */
 1350                         pr->ndpr_refcnt++;
 1351                         ia6->ia6_ndpr = pr;
 1352 
 1353                         /*
 1354                          * A newly added address might affect the status
 1355                          * of other addresses, so we check and update it.
 1356                          * XXX: what if address duplication happens?
 1357                          */
 1358                         pfxlist_onlink_check();
 1359                 } else {
 1360                         /* just set an error. do not bark here. */
 1361                         error = EADDRNOTAVAIL; /* XXX: might be unused. */
 1362                 }
 1363         }
 1364 
 1365  end:
 1366         splx(s);
 1367         return error;
 1368 }
 1369 
 1370 /*
 1371  * A supplement function used in the on-link detection below;
 1372  * detect if a given prefix has a (probably) reachable advertising router.
 1373  * XXX: lengthy function name...
 1374  */
 1375 static struct nd_pfxrouter *
 1376 find_pfxlist_reachable_router(pr)
 1377         struct nd_prefix *pr;
 1378 {
 1379         struct nd_pfxrouter *pfxrtr;
 1380         struct rtentry *rt;
 1381         struct llinfo_nd6 *ln;
 1382 
 1383         for (pfxrtr = LIST_FIRST(&pr->ndpr_advrtrs); pfxrtr;
 1384              pfxrtr = LIST_NEXT(pfxrtr, pfr_entry)) {
 1385                 if ((rt = nd6_lookup(&pfxrtr->router->rtaddr, 0,
 1386                     pfxrtr->router->ifp)) &&
 1387                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
 1388                     ND6_IS_LLINFO_PROBREACH(ln))
 1389                         break;  /* found */
 1390         }
 1391 
 1392         return (pfxrtr);
 1393 }
 1394 
 1395 /*
 1396  * Check if each prefix in the prefix list has at least one available router
 1397  * that advertised the prefix (a router is "available" if its neighbor cache
 1398  * entry is reachable or probably reachable).
 1399  * If the check fails, the prefix may be off-link, because, for example,
 1400  * we have moved from the network but the lifetime of the prefix has not
 1401  * expired yet.  So we should not use the prefix if there is another prefix
 1402  * that has an available router.
 1403  * But, if there is no prefix that has an available router, we still regards
 1404  * all the prefixes as on-link.  This is because we can't tell if all the
 1405  * routers are simply dead or if we really moved from the network and there
 1406  * is no router around us.
 1407  */
 1408 void
 1409 pfxlist_onlink_check()
 1410 {
 1411         struct nd_prefix *pr;
 1412         struct in6_ifaddr *ifa;
 1413 
 1414         /*
 1415          * Check if there is a prefix that has a reachable advertising
 1416          * router.
 1417          */
 1418         for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1419                 if (pr->ndpr_raf_onlink && find_pfxlist_reachable_router(pr))
 1420                         break;
 1421         }
 1422         if (pr != NULL || TAILQ_FIRST(&nd_defrouter) != NULL) {
 1423                 /*
 1424                  * There is at least one prefix that has a reachable router,
 1425                  * or at least a router which probably does not advertise
 1426                  * any prefixes.  The latter would be the case when we move
 1427                  * to a new link where we have a router that does not provide
 1428                  * prefixes and we configure an address by hand.
 1429                  * Detach prefixes which have no reachable advertising
 1430                  * router, and attach other prefixes.
 1431                  */
 1432                 for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1433                         /* XXX: a link-local prefix should never be detached */
 1434                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1435                                 continue;
 1436 
 1437                         /*
 1438                          * we aren't interested in prefixes without the L bit
 1439                          * set.
 1440                          */
 1441                         if (pr->ndpr_raf_onlink == 0)
 1442                                 continue;
 1443 
 1444                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1445                             find_pfxlist_reachable_router(pr) == NULL)
 1446                                 pr->ndpr_stateflags |= NDPRF_DETACHED;
 1447                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1448                             find_pfxlist_reachable_router(pr) != 0)
 1449                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1450                 }
 1451         } else {
 1452                 /* there is no prefix that has a reachable router */
 1453                 for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1454                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1455                                 continue;
 1456 
 1457                         if (pr->ndpr_raf_onlink == 0)
 1458                                 continue;
 1459 
 1460                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1461                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1462                 }
 1463         }
 1464 
 1465         /*
 1466          * Remove each interface route associated with a (just) detached
 1467          * prefix, and reinstall the interface route for a (just) attached
 1468          * prefix.  Note that all attempt of reinstallation does not
 1469          * necessarily success, when a same prefix is shared among multiple
 1470          * interfaces.  Such cases will be handled in nd6_prefix_onlink,
 1471          * so we don't have to care about them.
 1472          */
 1473         for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1474                 int e;
 1475 
 1476                 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1477                         continue;
 1478 
 1479                 if (pr->ndpr_raf_onlink == 0)
 1480                         continue;
 1481 
 1482                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1483                     (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1484                         if ((e = nd6_prefix_offlink(pr)) != 0) {
 1485                                 nd6log((LOG_ERR,
 1486                                     "pfxlist_onlink_check: failed to "
 1487                                     "make %s/%d offlink, errno=%d\n",
 1488                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1489                                     pr->ndpr_plen, e));
 1490                         }
 1491                 }
 1492                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1493                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0 &&
 1494                     pr->ndpr_raf_onlink) {
 1495                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1496                                 nd6log((LOG_ERR,
 1497                                     "pfxlist_onlink_check: failed to "
 1498                                     "make %s/%d offlink, errno=%d\n",
 1499                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1500                                     pr->ndpr_plen, e));
 1501                         }
 1502                 }
 1503         }
 1504 
 1505         /*
 1506          * Changes on the prefix status might affect address status as well.
 1507          * Make sure that all addresses derived from an attached prefix are
 1508          * attached, and that all addresses derived from a detached prefix are
 1509          * detached.  Note, however, that a manually configured address should
 1510          * always be attached.
 1511          * The precise detection logic is same as the one for prefixes.
 1512          */
 1513         for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1514                 if (!(ifa->ia6_flags & IN6_IFF_AUTOCONF))
 1515                         continue;
 1516 
 1517                 if (ifa->ia6_ndpr == NULL) {
 1518                         /*
 1519                          * This can happen when we first configure the address
 1520                          * (i.e. the address exists, but the prefix does not).
 1521                          * XXX: complicated relationships...
 1522                          */
 1523                         continue;
 1524                 }
 1525 
 1526                 if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
 1527                         break;
 1528         }
 1529         if (ifa) {
 1530                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1531                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1532                                 continue;
 1533 
 1534                         if (ifa->ia6_ndpr == NULL) /* XXX: see above. */
 1535                                 continue;
 1536 
 1537                         if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
 1538                                 ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1539                         else
 1540                                 ifa->ia6_flags |= IN6_IFF_DETACHED;
 1541                 }
 1542         }
 1543         else {
 1544                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1545                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1546                                 continue;
 1547 
 1548                         ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1549                 }
 1550         }
 1551 }
 1552 
 1553 int
 1554 nd6_prefix_onlink(pr)
 1555         struct nd_prefix *pr;
 1556 {
 1557         struct ifaddr *ifa;
 1558         struct ifnet *ifp = pr->ndpr_ifp;
 1559         struct sockaddr_in6 mask6;
 1560         struct nd_prefix *opr;
 1561         u_long rtflags;
 1562         int error = 0;
 1563         struct rtentry *rt = NULL;
 1564 
 1565         /* sanity check */
 1566         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1567                 nd6log((LOG_ERR,
 1568                     "nd6_prefix_onlink: %s/%d is already on-link\n",
 1569                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen);
 1570                 return (EEXIST));
 1571         }
 1572 
 1573         /*
 1574          * Add the interface route associated with the prefix.  Before
 1575          * installing the route, check if there's the same prefix on another
 1576          * interface, and the prefix has already installed the interface route.
 1577          * Although such a configuration is expected to be rare, we explicitly
 1578          * allow it.
 1579          */
 1580         for (opr = nd_prefix.lh_first; opr; opr = opr->ndpr_next) {
 1581                 if (opr == pr)
 1582                         continue;
 1583 
 1584                 if ((opr->ndpr_stateflags & NDPRF_ONLINK) == 0)
 1585                         continue;
 1586 
 1587                 if (opr->ndpr_plen == pr->ndpr_plen &&
 1588                     in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1589                     &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen))
 1590                         return (0);
 1591         }
 1592 
 1593         /*
 1594          * We prefer link-local addresses as the associated interface address.
 1595          */
 1596         /* search for a link-local addr */
 1597         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
 1598             IN6_IFF_NOTREADY | IN6_IFF_ANYCAST);
 1599         if (ifa == NULL) {
 1600                 /* XXX: freebsd does not have ifa_ifwithaf */
 1601                 for (ifa = ifp->if_addrlist.tqh_first;
 1602                      ifa;
 1603                      ifa = ifa->ifa_list.tqe_next)
 1604                 {
 1605                         if (ifa->ifa_addr->sa_family == AF_INET6)
 1606                                 break;
 1607                 }
 1608                 /* should we care about ia6_flags? */
 1609         }
 1610         if (ifa == NULL) {
 1611                 /*
 1612                  * This can still happen, when, for example, we receive an RA
 1613                  * containing a prefix with the L bit set and the A bit clear,
 1614                  * after removing all IPv6 addresses on the receiving
 1615                  * interface.  This should, of course, be rare though.
 1616                  */
 1617                 nd6log((LOG_NOTICE,
 1618                     "nd6_prefix_onlink: failed to find any ifaddr"
 1619                     " to add route for a prefix(%s/%d) on %s\n",
 1620                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1621                     pr->ndpr_plen, if_name(ifp)));
 1622                 return (0);
 1623         }
 1624 
 1625         /*
 1626          * in6_ifinit() sets nd6_rtrequest to ifa_rtrequest for all ifaddrs.
 1627          * ifa->ifa_rtrequest = nd6_rtrequest;
 1628          */
 1629         bzero(&mask6, sizeof(mask6));
 1630         mask6.sin6_len = sizeof(mask6);
 1631         mask6.sin6_addr = pr->ndpr_mask;
 1632         /* rtrequest() will probably set RTF_UP, but we're not sure. */
 1633         rtflags = ifa->ifa_flags | RTF_UP;
 1634         if (nd6_need_cache(ifp)) {
 1635                 /* explicitly set in case ifa_flags does not set the flag. */
 1636                 rtflags |= RTF_CLONING;
 1637         } else {
 1638                 /*
 1639                  * explicitly clear the cloning bit in case ifa_flags sets it.
 1640                  */
 1641                 rtflags &= ~RTF_CLONING;
 1642         }
 1643         error = rtrequest(RTM_ADD, (struct sockaddr *)&pr->ndpr_prefix,
 1644             ifa->ifa_addr, (struct sockaddr *)&mask6, rtflags, &rt);
 1645         if (error == 0) {
 1646                 if (rt != NULL) /* this should be non NULL, though */
 1647                         nd6_rtmsg(RTM_ADD, rt);
 1648                 pr->ndpr_stateflags |= NDPRF_ONLINK;
 1649         } else {
 1650                 nd6log((LOG_ERR, "nd6_prefix_onlink: failed to add route for a"
 1651                     " prefix (%s/%d) on %s, gw=%s, mask=%s, flags=%lx "
 1652                     "errno = %d\n",
 1653                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1654                     pr->ndpr_plen, if_name(ifp),
 1655                     ip6_sprintf(&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr),
 1656                     ip6_sprintf(&mask6.sin6_addr), rtflags, error));
 1657         }
 1658 
 1659         if (rt != NULL)
 1660                 rt->rt_refcnt--;
 1661 
 1662         return (error);
 1663 }
 1664 
 1665 int
 1666 nd6_prefix_offlink(pr)
 1667         struct nd_prefix *pr;
 1668 {
 1669         int error = 0;
 1670         struct ifnet *ifp = pr->ndpr_ifp;
 1671         struct nd_prefix *opr;
 1672         struct sockaddr_in6 sa6, mask6;
 1673         struct rtentry *rt = NULL;
 1674 
 1675         /* sanity check */
 1676         if ((pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1677                 nd6log((LOG_ERR,
 1678                     "nd6_prefix_offlink: %s/%d is already off-link\n",
 1679                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen));
 1680                 return (EEXIST);
 1681         }
 1682 
 1683         bzero(&sa6, sizeof(sa6));
 1684         sa6.sin6_family = AF_INET6;
 1685         sa6.sin6_len = sizeof(sa6);
 1686         bcopy(&pr->ndpr_prefix.sin6_addr, &sa6.sin6_addr,
 1687             sizeof(struct in6_addr));
 1688         bzero(&mask6, sizeof(mask6));
 1689         mask6.sin6_family = AF_INET6;
 1690         mask6.sin6_len = sizeof(sa6);
 1691         bcopy(&pr->ndpr_mask, &mask6.sin6_addr, sizeof(struct in6_addr));
 1692         error = rtrequest(RTM_DELETE, (struct sockaddr *)&sa6, NULL,
 1693             (struct sockaddr *)&mask6, 0, &rt);
 1694         if (error == 0) {
 1695                 pr->ndpr_stateflags &= ~NDPRF_ONLINK;
 1696 
 1697                 /* report the route deletion to the routing socket. */
 1698                 if (rt != NULL)
 1699                         nd6_rtmsg(RTM_DELETE, rt);
 1700 
 1701                 /*
 1702                  * There might be the same prefix on another interface,
 1703                  * the prefix which could not be on-link just because we have
 1704                  * the interface route (see comments in nd6_prefix_onlink).
 1705                  * If there's one, try to make the prefix on-link on the
 1706                  * interface.
 1707                  */
 1708                 for (opr = nd_prefix.lh_first; opr; opr = opr->ndpr_next) {
 1709                         if (opr == pr)
 1710                                 continue;
 1711 
 1712                         if ((opr->ndpr_stateflags & NDPRF_ONLINK) != 0)
 1713                                 continue;
 1714 
 1715                         /*
 1716                          * KAME specific: detached prefixes should not be
 1717                          * on-link.
 1718                          */
 1719                         if ((opr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1720                                 continue;
 1721 
 1722                         if (opr->ndpr_plen == pr->ndpr_plen &&
 1723                             in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1724                             &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
 1725                                 int e;
 1726 
 1727                                 if ((e = nd6_prefix_onlink(opr)) != 0) {
 1728                                         nd6log((LOG_ERR,
 1729                                             "nd6_prefix_offlink: failed to "
 1730                                             "recover a prefix %s/%d from %s "
 1731                                             "to %s (errno = %d)\n",
 1732                                             ip6_sprintf(&opr->ndpr_prefix.sin6_addr),
 1733                                             opr->ndpr_plen, if_name(ifp),
 1734                                             if_name(opr->ndpr_ifp), e));
 1735                                 }
 1736                         }
 1737                 }
 1738         } else {
 1739                 /* XXX: can we still set the NDPRF_ONLINK flag? */
 1740                 nd6log((LOG_ERR,
 1741                     "nd6_prefix_offlink: failed to delete route: "
 1742                     "%s/%d on %s (errno = %d)\n",
 1743                     ip6_sprintf(&sa6.sin6_addr), pr->ndpr_plen, if_name(ifp),
 1744                     error));
 1745         }
 1746 
 1747         if (rt != NULL) {
 1748                 if (rt->rt_refcnt <= 0) {
 1749                         /* XXX: we should free the entry ourselves. */
 1750                         rt->rt_refcnt++;
 1751                         rtfree(rt);
 1752                 }
 1753         }
 1754 
 1755         return (error);
 1756 }
 1757 
 1758 static struct in6_ifaddr *
 1759 in6_ifadd(pr)
 1760         struct nd_prefix *pr;
 1761 {
 1762         struct ifnet *ifp = pr->ndpr_ifp;
 1763         struct ifaddr *ifa;
 1764         struct in6_aliasreq ifra;
 1765         struct in6_ifaddr *ia, *ib;
 1766         int error, plen0;
 1767         struct in6_addr mask;
 1768         int prefixlen = pr->ndpr_plen;
 1769 
 1770         in6_prefixlen2mask(&mask, prefixlen);
 1771 
 1772         /*
 1773          * find a link-local address (will be interface ID).
 1774          * Is it really mandatory? Theoretically, a global or a site-local
 1775          * address can be configured without a link-local address, if we
 1776          * have a unique interface identifier...
 1777          *
 1778          * it is not mandatory to have a link-local address, we can generate
 1779          * interface identifier on the fly.  we do this because:
 1780          * (1) it should be the easiest way to find interface identifier.
 1781          * (2) RFC2462 5.4 suggesting the use of the same interface identifier
 1782          * for multiple addresses on a single interface, and possible shortcut
 1783          * of DAD.  we omitted DAD for this reason in the past.
 1784          * (3) a user can prevent autoconfiguration of global address
 1785          * by removing link-local address by hand (this is partly because we
 1786          * don't have other way to control the use of IPv6 on a interface.
 1787          * this has been our design choice - cf. NRL's "ifconfig auto").
 1788          * (4) it is easier to manage when an interface has addresses
 1789          * with the same interface identifier, than to have multiple addresses
 1790          * with different interface identifiers.
 1791          */
 1792         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0); /* 0 is OK? */
 1793         if (ifa)
 1794                 ib = (struct in6_ifaddr *)ifa;
 1795         else
 1796                 return NULL;
 1797 
 1798 #if 0 /* don't care link local addr state, and always do DAD */
 1799         /* if link-local address is not eligible, do not autoconfigure. */
 1800         if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY) {
 1801                 printf("in6_ifadd: link-local address not ready\n");
 1802                 return NULL;
 1803         }
 1804 #endif
 1805 
 1806         /* prefixlen + ifidlen must be equal to 128 */
 1807         plen0 = in6_mask2len(&ib->ia_prefixmask.sin6_addr, NULL);
 1808         if (prefixlen != plen0) {
 1809                 nd6log((LOG_ERR, "in6_ifadd: wrong prefixlen for %s"
 1810                     "(prefix=%d ifid=%d)\n",
 1811                     if_name(ifp), prefixlen, 128 - plen0));
 1812                 return NULL;
 1813         }
 1814 
 1815         /* make ifaddr */
 1816 
 1817         bzero(&ifra, sizeof(ifra));
 1818         /*
 1819          * in6_update_ifa() does not use ifra_name, but we accurately set it
 1820          * for safety.
 1821          */
 1822         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1823         ifra.ifra_addr.sin6_family = AF_INET6;
 1824         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
 1825         /* prefix */
 1826         bcopy(&pr->ndpr_prefix.sin6_addr, &ifra.ifra_addr.sin6_addr,
 1827             sizeof(ifra.ifra_addr.sin6_addr));
 1828         ifra.ifra_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
 1829         ifra.ifra_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
 1830         ifra.ifra_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
 1831         ifra.ifra_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
 1832 
 1833         /* interface ID */
 1834         ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
 1835             (ib->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
 1836         ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
 1837             (ib->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
 1838         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1839             (ib->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
 1840         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1841             (ib->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);
 1842 
 1843         /* new prefix mask. */
 1844         ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
 1845         ifra.ifra_prefixmask.sin6_family = AF_INET6;
 1846         bcopy(&mask, &ifra.ifra_prefixmask.sin6_addr,
 1847             sizeof(ifra.ifra_prefixmask.sin6_addr));
 1848 
 1849         /*
 1850          * lifetime.
 1851          * XXX: in6_init_address_ltimes would override these values later.
 1852          * We should reconsider this logic.
 1853          */
 1854         ifra.ifra_lifetime.ia6t_vltime = pr->ndpr_vltime;
 1855         ifra.ifra_lifetime.ia6t_pltime = pr->ndpr_pltime;
 1856 
 1857         /* XXX: scope zone ID? */
 1858 
 1859         ifra.ifra_flags |= IN6_IFF_AUTOCONF; /* obey autoconf */
 1860 
 1861         /* allocate ifaddr structure, link into chain, etc. */
 1862         if ((error = in6_update_ifa(ifp, &ifra, NULL)) != 0) {
 1863                 nd6log((LOG_ERR,
 1864                     "in6_ifadd: failed to make ifaddr %s on %s (errno=%d)\n",
 1865                     ip6_sprintf(&ifra.ifra_addr.sin6_addr), if_name(ifp),
 1866                     error));
 1867                 return (NULL);  /* ifaddr must not have been allocated. */
 1868         }
 1869 
 1870         ia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1871 
 1872         return (ia);            /* this is always non-NULL */
 1873 }
 1874 
 1875 int
 1876 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
 1877 {
 1878 
 1879         /* check if preferred lifetime > valid lifetime.  RFC2462 5.5.3 (c) */
 1880         if (ndpr->ndpr_pltime > ndpr->ndpr_vltime) {
 1881                 nd6log((LOG_INFO, "in6_init_prefix_ltimes: preferred lifetime"
 1882                     "(%d) is greater than valid lifetime(%d)\n",
 1883                     (u_int)ndpr->ndpr_pltime, (u_int)ndpr->ndpr_vltime));
 1884                 return (EINVAL);
 1885         }
 1886         if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
 1887                 ndpr->ndpr_preferred = 0;
 1888         else
 1889                 ndpr->ndpr_preferred = time.tv_sec + ndpr->ndpr_pltime;
 1890         if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
 1891                 ndpr->ndpr_expire = 0;
 1892         else
 1893                 ndpr->ndpr_expire = time.tv_sec + ndpr->ndpr_vltime;
 1894 
 1895         return 0;
 1896 }
 1897 
 1898 static void
 1899 in6_init_address_ltimes(struct nd_prefix *new, struct in6_addrlifetime *lt6)
 1900 {
 1901 
 1902         /* Valid lifetime must not be updated unless explicitly specified. */
 1903         /* init ia6t_expire */
 1904         if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
 1905                 lt6->ia6t_expire = 0;
 1906         else {
 1907                 lt6->ia6t_expire = time.tv_sec;
 1908                 lt6->ia6t_expire += lt6->ia6t_vltime;
 1909         }
 1910 
 1911         /* init ia6t_preferred */
 1912         if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
 1913                 lt6->ia6t_preferred = 0;
 1914         else {
 1915                 lt6->ia6t_preferred = time.tv_sec;
 1916                 lt6->ia6t_preferred += lt6->ia6t_pltime;
 1917         }
 1918 }
 1919 
 1920 /*
 1921  * Delete all the routing table entries that use the specified gateway.
 1922  * XXX: this function causes search through all entries of routing table, so
 1923  * it shouldn't be called when acting as a router.
 1924  */
 1925 void
 1926 rt6_flush(gateway, ifp)
 1927         struct in6_addr *gateway;
 1928         struct ifnet *ifp;
 1929 {
 1930         struct radix_node_head *rnh = rt_tables[AF_INET6];
 1931         int s = splsoftnet();
 1932 
 1933         /* We'll care only link-local addresses */
 1934         if (!IN6_IS_ADDR_LINKLOCAL(gateway)) {
 1935                 splx(s);
 1936                 return;
 1937         }
 1938         /* XXX: hack for KAME's link-local address kludge */
 1939         gateway->s6_addr16[1] = htons(ifp->if_index);
 1940 
 1941         rnh->rnh_walktree(rnh, rt6_deleteroute, (void *)gateway);
 1942         splx(s);
 1943 }
 1944 
 1945 static int
 1946 rt6_deleteroute(rn, arg)
 1947         struct radix_node *rn;
 1948         void *arg;
 1949 {
 1950 #define SIN6(s) ((struct sockaddr_in6 *)s)
 1951         struct rtentry *rt = (struct rtentry *)rn;
 1952         struct in6_addr *gate = (struct in6_addr *)arg;
 1953 
 1954         if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
 1955                 return (0);
 1956 
 1957         if (!IN6_ARE_ADDR_EQUAL(gate, &SIN6(rt->rt_gateway)->sin6_addr))
 1958                 return (0);
 1959 
 1960         /*
 1961          * Do not delete a static route.
 1962          * XXX: this seems to be a bit ad-hoc. Should we consider the
 1963          * 'cloned' bit instead?
 1964          */
 1965         if ((rt->rt_flags & RTF_STATIC) != 0)
 1966                 return (0);
 1967 
 1968         /*
 1969          * We delete only host route. This means, in particular, we don't
 1970          * delete default route.
 1971          */
 1972         if ((rt->rt_flags & RTF_HOST) == 0)
 1973                 return (0);
 1974 
 1975         return (rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
 1976             rt_mask(rt), rt->rt_flags, 0));
 1977 #undef SIN6
 1978 }
 1979 
 1980 int
 1981 nd6_setdefaultiface(ifindex)
 1982         int ifindex;
 1983 {
 1984         int error = 0;
 1985 
 1986         if (ifindex < 0 || if_indexlim <= ifindex || !ifindex2ifnet[ifindex])
 1987                 return (EINVAL);
 1988 
 1989         if (nd6_defifindex != ifindex) {
 1990                 nd6_defifindex = ifindex;
 1991                 if (nd6_defifindex > 0) {
 1992                         nd6_defifp = ifindex2ifnet[nd6_defifindex];
 1993                 } else
 1994                         nd6_defifp = NULL;
 1995 
 1996                 /*
 1997                  * Rescan default router list, refresh default route(s).
 1998                  */
 1999                 defrouter_select();
 2000         }
 2001 
 2002         return (error);
 2003 }

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