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 1.76 2008/10/24 21:30:34 dyoung 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 1.76 2008/10/24 21:30:34 dyoung 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 <netinet6/in6_ifattach.h>
   57 #include <netinet/ip6.h>
   58 #include <netinet6/ip6_var.h>
   59 #include <netinet6/nd6.h>
   60 #include <netinet/icmp6.h>
   61 #include <netinet6/icmp6_private.h>
   62 #include <netinet6/scope6_var.h>
   63 
   64 #include <net/net_osdep.h>
   65 
   66 static int rtpref(struct nd_defrouter *);
   67 static struct nd_defrouter *defrtrlist_update(struct nd_defrouter *);
   68 static int prelist_update(struct nd_prefixctl *, struct nd_defrouter *,
   69     struct mbuf *, int);
   70 static struct in6_ifaddr *in6_ifadd(struct nd_prefixctl *, int);
   71 static struct nd_pfxrouter *pfxrtr_lookup(struct nd_prefix *,
   72         struct nd_defrouter *);
   73 static void pfxrtr_add(struct nd_prefix *, struct nd_defrouter *);
   74 static void pfxrtr_del(struct nd_pfxrouter *);
   75 static struct nd_pfxrouter *find_pfxlist_reachable_router
   76         (struct nd_prefix *);
   77 static void defrouter_delreq(struct nd_defrouter *);
   78 static void nd6_rtmsg(int, struct rtentry *);
   79 
   80 static int in6_init_prefix_ltimes(struct nd_prefix *);
   81 static void in6_init_address_ltimes(struct nd_prefix *ndpr,
   82         struct in6_addrlifetime *lt6);
   83 
   84 static int rt6_deleteroute(struct rtentry *, void *);
   85 
   86 extern int nd6_recalc_reachtm_interval;
   87 
   88 static struct ifnet *nd6_defifp;
   89 int nd6_defifindex;
   90 
   91 int ip6_use_tempaddr = 0;
   92 
   93 int ip6_desync_factor;
   94 u_int32_t ip6_temp_preferred_lifetime = DEF_TEMP_PREFERRED_LIFETIME;
   95 u_int32_t ip6_temp_valid_lifetime = DEF_TEMP_VALID_LIFETIME;
   96 int ip6_temp_regen_advance = TEMPADDR_REGEN_ADVANCE;
   97 
   98 /* RTPREF_MEDIUM has to be 0! */
   99 #define RTPREF_HIGH     1
  100 #define RTPREF_MEDIUM   0
  101 #define RTPREF_LOW      (-1)
  102 #define RTPREF_RESERVED (-2)
  103 #define RTPREF_INVALID  (-3)    /* internal */
  104 
  105 /*
  106  * Receive Router Solicitation Message - just for routers.
  107  * Router solicitation/advertisement is mostly managed by userland program
  108  * (rtadvd) so here we have no function like nd6_ra_output().
  109  *
  110  * Based on RFC 2461
  111  */
  112 void
  113 nd6_rs_input(struct mbuf *m, int off, int icmp6len)
  114 {
  115         struct ifnet *ifp = m->m_pkthdr.rcvif;
  116         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  117         struct nd_router_solicit *nd_rs;
  118         struct in6_addr saddr6 = ip6->ip6_src;
  119         char *lladdr = NULL;
  120         int lladdrlen = 0;
  121         union nd_opts ndopts;
  122 
  123         /* If I'm not a router, ignore it. */
  124         if (ip6_accept_rtadv != 0 || !ip6_forwarding)
  125                 goto freeit;
  126 
  127         /* Sanity checks */
  128         if (ip6->ip6_hlim != 255) {
  129                 nd6log((LOG_ERR,
  130                     "nd6_rs_input: invalid hlim (%d) from %s to %s on %s\n",
  131                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  132                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  133                 goto bad;
  134         }
  135 
  136         /*
  137          * Don't update the neighbor cache, if src = ::.
  138          * This indicates that the src has no IP address assigned yet.
  139          */
  140         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  141                 goto freeit;
  142 
  143         IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
  144         if (nd_rs == NULL) {
  145                 ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
  146                 return;
  147         }
  148 
  149         icmp6len -= sizeof(*nd_rs);
  150         nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
  151         if (nd6_options(&ndopts) < 0) {
  152                 nd6log((LOG_INFO,
  153                     "nd6_rs_input: invalid ND option, ignored\n"));
  154                 /* nd6_options have incremented stats */
  155                 goto freeit;
  156         }
  157 
  158         if (ndopts.nd_opts_src_lladdr) {
  159                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  160                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  161         }
  162 
  163         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  164                 nd6log((LOG_INFO,
  165                     "nd6_rs_input: lladdrlen mismatch for %s "
  166                     "(if %d, RS packet %d)\n",
  167                     ip6_sprintf(&saddr6), ifp->if_addrlen, lladdrlen - 2));
  168                 goto bad;
  169         }
  170 
  171         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
  172 
  173  freeit:
  174         m_freem(m);
  175         return;
  176 
  177  bad:
  178         ICMP6_STATINC(ICMP6_STAT_BADRS);
  179         m_freem(m);
  180 }
  181 
  182 /*
  183  * Receive Router Advertisement Message.
  184  *
  185  * Based on RFC 2461
  186  * TODO: on-link bit on prefix information
  187  * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
  188  */
  189 void
  190 nd6_ra_input(struct mbuf *m, int off, int icmp6len)
  191 {
  192         struct ifnet *ifp = m->m_pkthdr.rcvif;
  193         struct nd_ifinfo *ndi = ND_IFINFO(ifp);
  194         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  195         struct nd_router_advert *nd_ra;
  196         struct in6_addr saddr6 = ip6->ip6_src;
  197 #if 0
  198         struct in6_addr daddr6 = ip6->ip6_dst;
  199         int flags; /* = nd_ra->nd_ra_flags_reserved; */
  200         int is_managed = ((flags & ND_RA_FLAG_MANAGED) != 0);
  201         int is_other = ((flags & ND_RA_FLAG_OTHER) != 0);
  202 #endif
  203         int mcast = 0;
  204         union nd_opts ndopts;
  205         struct nd_defrouter *dr;
  206 
  207         /*
  208          * We only accept RAs only when
  209          * the system-wide variable allows the acceptance, and
  210          * per-interface variable allows RAs on the receiving interface.
  211          */
  212         if (ip6_accept_rtadv == 0)
  213                 goto freeit;
  214         if (!(ndi->flags & ND6_IFF_ACCEPT_RTADV))
  215                 goto freeit;
  216 
  217         if (ip6->ip6_hlim != 255) {
  218                 nd6log((LOG_ERR,
  219                     "nd6_ra_input: invalid hlim (%d) from %s to %s on %s\n",
  220                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  221                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  222                 goto bad;
  223         }
  224 
  225         if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
  226                 nd6log((LOG_ERR,
  227                     "nd6_ra_input: src %s is not link-local\n",
  228                     ip6_sprintf(&saddr6)));
  229                 goto bad;
  230         }
  231 
  232         IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
  233         if (nd_ra == NULL) {
  234                 ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
  235                 return;
  236         }
  237 
  238         icmp6len -= sizeof(*nd_ra);
  239         nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
  240         if (nd6_options(&ndopts) < 0) {
  241                 nd6log((LOG_INFO,
  242                     "nd6_ra_input: invalid ND option, ignored\n"));
  243                 /* nd6_options have incremented stats */
  244                 goto freeit;
  245         }
  246 
  247     {
  248         struct nd_defrouter drtr;
  249         u_int32_t advreachable = nd_ra->nd_ra_reachable;
  250 
  251         /* remember if this is a multicasted advertisement */
  252         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
  253                 mcast = 1;
  254 
  255         memset(&drtr, 0, sizeof(drtr));
  256         drtr.rtaddr = saddr6;
  257         drtr.flags  = nd_ra->nd_ra_flags_reserved;
  258         drtr.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
  259         drtr.expire = time_second + drtr.rtlifetime;
  260         drtr.ifp = ifp;
  261         /* unspecified or not? (RFC 2461 6.3.4) */
  262         if (advreachable) {
  263                 NTOHL(advreachable);
  264                 if (advreachable <= MAX_REACHABLE_TIME &&
  265                     ndi->basereachable != advreachable) {
  266                         ndi->basereachable = advreachable;
  267                         ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
  268                         ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
  269                 }
  270         }
  271         if (nd_ra->nd_ra_retransmit)
  272                 ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
  273         if (nd_ra->nd_ra_curhoplimit)
  274                 ndi->chlim = nd_ra->nd_ra_curhoplimit;
  275         dr = defrtrlist_update(&drtr);
  276     }
  277 
  278         /*
  279          * prefix
  280          */
  281         if (ndopts.nd_opts_pi) {
  282                 struct nd_opt_hdr *pt;
  283                 struct nd_opt_prefix_info *pi = NULL;
  284                 struct nd_prefixctl pr;
  285 
  286                 for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
  287                      pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
  288                      pt = (struct nd_opt_hdr *)((char *)pt +
  289                                                 (pt->nd_opt_len << 3))) {
  290                         if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
  291                                 continue;
  292                         pi = (struct nd_opt_prefix_info *)pt;
  293 
  294                         if (pi->nd_opt_pi_len != 4) {
  295                                 nd6log((LOG_INFO,
  296                                     "nd6_ra_input: invalid option "
  297                                     "len %d for prefix information option, "
  298                                     "ignored\n", pi->nd_opt_pi_len));
  299                                 continue;
  300                         }
  301 
  302                         if (128 < pi->nd_opt_pi_prefix_len) {
  303                                 nd6log((LOG_INFO,
  304                                     "nd6_ra_input: invalid prefix "
  305                                     "len %d for prefix information option, "
  306                                     "ignored\n", pi->nd_opt_pi_prefix_len));
  307                                 continue;
  308                         }
  309 
  310                         if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
  311                          || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
  312                                 nd6log((LOG_INFO,
  313                                     "nd6_ra_input: invalid prefix "
  314                                     "%s, ignored\n",
  315                                     ip6_sprintf(&pi->nd_opt_pi_prefix)));
  316                                 continue;
  317                         }
  318 
  319                         bzero(&pr, sizeof(pr));
  320                         sockaddr_in6_init(&pr.ndpr_prefix,
  321                             &pi->nd_opt_pi_prefix, 0, 0, 0);
  322                         pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;
  323 
  324                         pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
  325                             ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
  326                         pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
  327                             ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
  328                         pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
  329                         pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
  330                         pr.ndpr_pltime = ntohl(pi->nd_opt_pi_preferred_time);
  331 
  332                         (void)prelist_update(&pr, dr, m, mcast);
  333                 }
  334         }
  335 
  336         /*
  337          * MTU
  338          */
  339         if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
  340                 u_long mtu;
  341                 u_long maxmtu;
  342 
  343                 mtu = ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
  344 
  345                 /* lower bound */
  346                 if (mtu < IPV6_MMTU) {
  347                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
  348                             "mtu=%lu sent from %s, ignoring\n",
  349                             mtu, ip6_sprintf(&ip6->ip6_src)));
  350                         goto skip;
  351                 }
  352 
  353                 /* upper bound */
  354                 maxmtu = (ndi->maxmtu && ndi->maxmtu < ifp->if_mtu)
  355                     ? ndi->maxmtu : ifp->if_mtu;
  356                 if (mtu <= maxmtu) {
  357                         int change = (ndi->linkmtu != mtu);
  358 
  359                         ndi->linkmtu = mtu;
  360                         if (change) /* in6_maxmtu may change */
  361                                 in6_setmaxmtu();
  362                 } else {
  363                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
  364                             "mtu=%lu sent from %s; "
  365                             "exceeds maxmtu %lu, ignoring\n",
  366                             mtu, ip6_sprintf(&ip6->ip6_src), maxmtu));
  367                 }
  368         }
  369 
  370  skip:
  371 
  372         /*
  373          * Source link layer address
  374          */
  375     {
  376         char *lladdr = NULL;
  377         int lladdrlen = 0;
  378 
  379         if (ndopts.nd_opts_src_lladdr) {
  380                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  381                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  382         }
  383 
  384         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  385                 nd6log((LOG_INFO,
  386                     "nd6_ra_input: lladdrlen mismatch for %s "
  387                     "(if %d, RA packet %d)\n", ip6_sprintf(&saddr6),
  388                     ifp->if_addrlen, lladdrlen - 2));
  389                 goto bad;
  390         }
  391 
  392         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_ADVERT, 0);
  393 
  394         /*
  395          * Installing a link-layer address might change the state of the
  396          * router's neighbor cache, which might also affect our on-link
  397          * detection of adveritsed prefixes.
  398          */
  399         pfxlist_onlink_check();
  400     }
  401 
  402  freeit:
  403         m_freem(m);
  404         return;
  405 
  406  bad:
  407         ICMP6_STATINC(ICMP6_STAT_BADRA);
  408         m_freem(m);
  409 }
  410 
  411 /*
  412  * default router list processing sub routines
  413  */
  414 
  415 /* tell the change to user processes watching the routing socket. */
  416 static void
  417 nd6_rtmsg(int cmd, struct rtentry *rt)
  418 {
  419         struct rt_addrinfo info;
  420 
  421         bzero((void *)&info, sizeof(info));
  422         info.rti_info[RTAX_DST] = rt_getkey(rt);
  423         info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
  424         info.rti_info[RTAX_NETMASK] = rt_mask(rt);
  425         if (rt->rt_ifp) {
  426                 info.rti_info[RTAX_IFP] = rt->rt_ifp->if_dl->ifa_addr;
  427                 info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
  428         }
  429 
  430         rt_missmsg(cmd, &info, rt->rt_flags, 0);
  431 }
  432 
  433 void
  434 defrouter_addreq(struct nd_defrouter *new)
  435 {
  436         union {
  437                 struct sockaddr_in6 sin6;
  438                 struct sockaddr sa;
  439         } def, mask, gate;
  440         struct rtentry *newrt = NULL;
  441         int s;
  442         int error;
  443 
  444         memset(&def, 0, sizeof(def));
  445         memset(&mask, 0, sizeof(mask));
  446         memset(&gate, 0,sizeof(gate)); /* for safety */
  447 
  448         def.sin6.sin6_len = mask.sin6.sin6_len = gate.sin6.sin6_len =
  449             sizeof(struct sockaddr_in6);
  450         def.sin6.sin6_family = mask.sin6.sin6_family = gate.sin6.sin6_family = AF_INET6;
  451         gate.sin6.sin6_addr = new->rtaddr;
  452 #ifndef SCOPEDROUTING
  453         gate.sin6.sin6_scope_id = 0;    /* XXX */
  454 #endif
  455 
  456         s = splsoftnet();
  457         error = rtrequest(RTM_ADD, &def.sa, &gate.sa, &mask.sa,
  458             RTF_GATEWAY, &newrt);
  459         if (newrt) {
  460                 nd6_rtmsg(RTM_ADD, newrt); /* tell user process */
  461                 newrt->rt_refcnt--;
  462         }
  463         if (error == 0)
  464                 new->installed = 1;
  465         splx(s);
  466         return;
  467 }
  468 
  469 struct nd_defrouter *
  470 defrouter_lookup(const struct in6_addr *addr, struct ifnet *ifp)
  471 {
  472         struct nd_defrouter *dr;
  473 
  474         TAILQ_FOREACH(dr, &nd_defrouter, dr_entry) {
  475                 if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr))
  476                         break;
  477         }
  478 
  479         return dr;              /* search failed */
  480 }
  481 
  482 void
  483 defrtrlist_del(struct nd_defrouter *dr)
  484 {
  485         struct nd_defrouter *deldr = NULL;
  486         struct nd_prefix *pr;
  487 
  488         /*
  489          * Flush all the routing table entries that use the router
  490          * as a next hop.
  491          */
  492         if (!ip6_forwarding && ip6_accept_rtadv) /* XXX: better condition? */
  493                 rt6_flush(&dr->rtaddr, dr->ifp);
  494 
  495         if (dr->installed) {
  496                 deldr = dr;
  497                 defrouter_delreq(dr);
  498         }
  499         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  500 
  501         /*
  502          * Also delete all the pointers to the router in each prefix lists.
  503          */
  504         LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
  505                 struct nd_pfxrouter *pfxrtr;
  506                 if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
  507                         pfxrtr_del(pfxrtr);
  508         }
  509         pfxlist_onlink_check();
  510 
  511         /*
  512          * If the router is the primary one, choose a new one.
  513          * Note that defrouter_select() will remove the current gateway
  514          * from the routing table.
  515          */
  516         if (deldr)
  517                 defrouter_select();
  518 
  519         free(dr, M_IP6NDP);
  520 }
  521 
  522 /*
  523  * Remove the default route for a given router.
  524  * This is just a subroutine function for defrouter_select(), and should
  525  * not be called from anywhere else.
  526  */
  527 static void
  528 defrouter_delreq(struct nd_defrouter *dr)
  529 {
  530         union {
  531                 struct sockaddr_in6 sin6;
  532                 struct sockaddr sa;
  533         } def, mask, gw;
  534         struct rtentry *oldrt = NULL;
  535 
  536 #ifdef DIAGNOSTIC
  537         if (dr == NULL)
  538                 panic("dr == NULL in defrouter_delreq");
  539 #endif
  540 
  541         memset(&def, 0, sizeof(def));
  542         memset(&mask, 0, sizeof(mask));
  543         memset(&gw, 0, sizeof(gw));     /* for safety */
  544 
  545         def.sin6.sin6_len = mask.sin6.sin6_len = gw.sin6.sin6_len =
  546             sizeof(struct sockaddr_in6);
  547         def.sin6.sin6_family = mask.sin6.sin6_family = gw.sin6.sin6_family = AF_INET6;
  548         gw.sin6.sin6_addr = dr->rtaddr;
  549 #ifndef SCOPEDROUTING
  550         gw.sin6.sin6_scope_id = 0;      /* XXX */
  551 #endif
  552 
  553         rtrequest(RTM_DELETE, &def.sa, &gw.sa, &mask.sa, RTF_GATEWAY, &oldrt);
  554         if (oldrt) {
  555                 nd6_rtmsg(RTM_DELETE, oldrt);
  556                 if (oldrt->rt_refcnt <= 0) {
  557                         /*
  558                          * XXX: borrowed from the RTM_DELETE case of
  559                          * rtrequest().
  560                          */
  561                         oldrt->rt_refcnt++;
  562                         rtfree(oldrt);
  563                 }
  564         }
  565 
  566         dr->installed = 0;
  567 }
  568 
  569 /*
  570  * remove all default routes from default router list
  571  */
  572 void
  573 defrouter_reset(void)
  574 {
  575         struct nd_defrouter *dr;
  576 
  577         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  578              dr = TAILQ_NEXT(dr, dr_entry))
  579                 defrouter_delreq(dr);
  580 
  581         /*
  582          * XXX should we also nuke any default routers in the kernel, by
  583          * going through them by rtalloc1()?
  584          */
  585 }
  586 
  587 /*
  588  * Default Router Selection according to Section 6.3.6 of RFC 2461 and
  589  * draft-ietf-ipngwg-router-selection:
  590  * 1) Routers that are reachable or probably reachable should be preferred.
  591  *    If we have more than one (probably) reachable router, prefer ones
  592  *    with the highest router preference.
  593  * 2) When no routers on the list are known to be reachable or
  594  *    probably reachable, routers SHOULD be selected in a round-robin
  595  *    fashion, regardless of router preference values.
  596  * 3) If the Default Router List is empty, assume that all
  597  *    destinations are on-link.
  598  *
  599  * We assume nd_defrouter is sorted by router preference value.
  600  * Since the code below covers both with and without router preference cases,
  601  * we do not need to classify the cases by ifdef.
  602  *
  603  * At this moment, we do not try to install more than one default router,
  604  * even when the multipath routing is available, because we're not sure about
  605  * the benefits for stub hosts comparing to the risk of making the code
  606  * complicated and the possibility of introducing bugs.
  607  */
  608 void
  609 defrouter_select(void)
  610 {
  611         int s = splsoftnet();
  612         struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
  613         struct rtentry *rt = NULL;
  614         struct llinfo_nd6 *ln = NULL;
  615 
  616         /*
  617          * This function should be called only when acting as an autoconfigured
  618          * host.  Although the remaining part of this function is not effective
  619          * if the node is not an autoconfigured host, we explicitly exclude
  620          * such cases here for safety.
  621          */
  622         if (ip6_forwarding || !ip6_accept_rtadv) {
  623                 nd6log((LOG_WARNING,
  624                     "defrouter_select: called unexpectedly (forwarding=%d, "
  625                     "accept_rtadv=%d)\n", ip6_forwarding, ip6_accept_rtadv));
  626                 splx(s);
  627                 return;
  628         }
  629 
  630         /*
  631          * Let's handle easy case (3) first:
  632          * If default router list is empty, there's nothing to be done.
  633          */
  634         if (!TAILQ_FIRST(&nd_defrouter)) {
  635                 splx(s);
  636                 return;
  637         }
  638 
  639         /*
  640          * Search for a (probably) reachable router from the list.
  641          * We just pick up the first reachable one (if any), assuming that
  642          * the ordering rule of the list described in defrtrlist_update().
  643          */
  644         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  645              dr = TAILQ_NEXT(dr, dr_entry)) {
  646                 if (selected_dr == NULL &&
  647                     (rt = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) != NULL &&
  648                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) != NULL &&
  649                     ND6_IS_LLINFO_PROBREACH(ln)) {
  650                         selected_dr = dr;
  651                 }
  652 
  653                 if (dr->installed && !installed_dr)
  654                         installed_dr = dr;
  655                 else if (dr->installed && installed_dr) {
  656                         /* this should not happen.  warn for diagnosis. */
  657                         log(LOG_ERR, "defrouter_select: more than one router"
  658                             " is installed\n");
  659                 }
  660         }
  661         /*
  662          * If none of the default routers was found to be reachable,
  663          * round-robin the list regardless of preference.
  664          * Otherwise, if we have an installed router, check if the selected
  665          * (reachable) router should really be preferred to the installed one.
  666          * We only prefer the new router when the old one is not reachable
  667          * or when the new one has a really higher preference value.
  668          */
  669         if (selected_dr == NULL) {
  670                 if (installed_dr == NULL || !TAILQ_NEXT(installed_dr, dr_entry))
  671                         selected_dr = TAILQ_FIRST(&nd_defrouter);
  672                 else
  673                         selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
  674         } else if (installed_dr &&
  675             (rt = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp)) &&
  676             (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
  677             ND6_IS_LLINFO_PROBREACH(ln) &&
  678             rtpref(selected_dr) <= rtpref(installed_dr)) {
  679                 selected_dr = installed_dr;
  680         }
  681 
  682         /*
  683          * If the selected router is different than the installed one,
  684          * remove the installed router and install the selected one.
  685          * Note that the selected router is never NULL here.
  686          */
  687         if (installed_dr != selected_dr) {
  688                 if (installed_dr)
  689                         defrouter_delreq(installed_dr);
  690                 defrouter_addreq(selected_dr);
  691         }
  692 
  693         splx(s);
  694         return;
  695 }
  696 
  697 /*
  698  * for default router selection
  699  * regards router-preference field as a 2-bit signed integer
  700  */
  701 static int
  702 rtpref(struct nd_defrouter *dr)
  703 {
  704         switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
  705         case ND_RA_FLAG_RTPREF_HIGH:
  706                 return (RTPREF_HIGH);
  707         case ND_RA_FLAG_RTPREF_MEDIUM:
  708         case ND_RA_FLAG_RTPREF_RSV:
  709                 return (RTPREF_MEDIUM);
  710         case ND_RA_FLAG_RTPREF_LOW:
  711                 return (RTPREF_LOW);
  712         default:
  713                 /*
  714                  * This case should never happen.  If it did, it would mean a
  715                  * serious bug of kernel internal.  We thus always bark here.
  716                  * Or, can we even panic?
  717                  */
  718                 log(LOG_ERR, "rtpref: impossible RA flag %x\n", dr->flags);
  719                 return (RTPREF_INVALID);
  720         }
  721         /* NOTREACHED */
  722 }
  723 
  724 static struct nd_defrouter *
  725 defrtrlist_update(struct nd_defrouter *new)
  726 {
  727         struct nd_defrouter *dr, *n;
  728         int s = splsoftnet();
  729 
  730         if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
  731                 /* entry exists */
  732                 if (new->rtlifetime == 0) {
  733                         defrtrlist_del(dr);
  734                         dr = NULL;
  735                 } else {
  736                         int oldpref = rtpref(dr);
  737 
  738                         /* override */
  739                         dr->flags = new->flags; /* xxx flag check */
  740                         dr->rtlifetime = new->rtlifetime;
  741                         dr->expire = new->expire;
  742 
  743                         /*
  744                          * If the preference does not change, there's no need
  745                          * to sort the entries.
  746                          */
  747                         if (rtpref(new) == oldpref) {
  748                                 splx(s);
  749                                 return (dr);
  750                         }
  751 
  752                         /*
  753                          * preferred router may be changed, so relocate
  754                          * this router.
  755                          * XXX: calling TAILQ_REMOVE directly is a bad manner.
  756                          * However, since defrtrlist_del() has many side
  757                          * effects, we intentionally do so here.
  758                          * defrouter_select() below will handle routing
  759                          * changes later.
  760                          */
  761                         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  762                         n = dr;
  763                         goto insert;
  764                 }
  765                 splx(s);
  766                 return (dr);
  767         }
  768 
  769         /* entry does not exist */
  770         if (new->rtlifetime == 0) {
  771                 splx(s);
  772                 return (NULL);
  773         }
  774 
  775         n = (struct nd_defrouter *)malloc(sizeof(*n), M_IP6NDP, M_NOWAIT);
  776         if (n == NULL) {
  777                 splx(s);
  778                 return (NULL);
  779         }
  780         bzero(n, sizeof(*n));
  781         *n = *new;
  782 
  783 insert:
  784         /*
  785          * Insert the new router in the Default Router List;
  786          * The Default Router List should be in the descending order
  787          * of router-preferece.  Routers with the same preference are
  788          * sorted in the arriving time order.
  789          */
  790 
  791         /* insert at the end of the group */
  792         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  793              dr = TAILQ_NEXT(dr, dr_entry)) {
  794                 if (rtpref(n) > rtpref(dr))
  795                         break;
  796         }
  797         if (dr)
  798                 TAILQ_INSERT_BEFORE(dr, n, dr_entry);
  799         else
  800                 TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);
  801 
  802         defrouter_select();
  803 
  804         splx(s);
  805 
  806         return (n);
  807 }
  808 
  809 static struct nd_pfxrouter *
  810 pfxrtr_lookup(struct nd_prefix *pr, struct nd_defrouter *dr)
  811 {
  812         struct nd_pfxrouter *search;
  813 
  814         LIST_FOREACH(search, &pr->ndpr_advrtrs, pfr_entry) {
  815                 if (search->router == dr)
  816                         break;
  817         }
  818 
  819         return (search);
  820 }
  821 
  822 static void
  823 pfxrtr_add(struct nd_prefix *pr, struct nd_defrouter *dr)
  824 {
  825         struct nd_pfxrouter *new;
  826 
  827         new = (struct nd_pfxrouter *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  828         if (new == NULL)
  829                 return;
  830         bzero(new, sizeof(*new));
  831         new->router = dr;
  832 
  833         LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
  834 
  835         pfxlist_onlink_check();
  836 }
  837 
  838 static void
  839 pfxrtr_del(struct nd_pfxrouter *pfr)
  840 {
  841         LIST_REMOVE(pfr, pfr_entry);
  842         free(pfr, M_IP6NDP);
  843 }
  844 
  845 struct nd_prefix *
  846 nd6_prefix_lookup(struct nd_prefixctl *key)
  847 {
  848         struct nd_prefix *search;
  849 
  850         LIST_FOREACH(search, &nd_prefix, ndpr_entry) {
  851                 if (key->ndpr_ifp == search->ndpr_ifp &&
  852                     key->ndpr_plen == search->ndpr_plen &&
  853                     in6_are_prefix_equal(&key->ndpr_prefix.sin6_addr,
  854                     &search->ndpr_prefix.sin6_addr, key->ndpr_plen)) {
  855                         break;
  856                 }
  857         }
  858 
  859         return (search);
  860 }
  861 
  862 int
  863 nd6_prelist_add(struct nd_prefixctl *pr, struct nd_defrouter *dr, 
  864         struct nd_prefix **newp)
  865 {
  866         struct nd_prefix *new = NULL;
  867         int i, s;
  868         int error;
  869 
  870         error = 0;
  871         new = (struct nd_prefix *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  872         if (new == NULL)
  873                 return ENOMEM;
  874         bzero(new, sizeof(*new));
  875         new->ndpr_ifp = pr->ndpr_ifp;
  876         new->ndpr_prefix = pr->ndpr_prefix;
  877         new->ndpr_plen = pr->ndpr_plen;
  878         new->ndpr_vltime = pr->ndpr_vltime;
  879         new->ndpr_pltime = pr->ndpr_pltime;
  880         new->ndpr_flags = pr->ndpr_flags;
  881         if ((error = in6_init_prefix_ltimes(new)) != 0) {
  882                 free(new, M_IP6NDP);
  883                 return(error);
  884         }
  885         new->ndpr_lastupdate = time_second;
  886         if (newp != NULL)
  887                 *newp = new;
  888 
  889         /* initialization */
  890         LIST_INIT(&new->ndpr_advrtrs);
  891         in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
  892         /* make prefix in the canonical form */
  893         for (i = 0; i < 4; i++)
  894                 new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
  895                     new->ndpr_mask.s6_addr32[i];
  896 
  897         s = splsoftnet();
  898         /* link ndpr_entry to nd_prefix list */
  899         LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
  900         splx(s);
  901 
  902         /* ND_OPT_PI_FLAG_ONLINK processing */
  903         if (new->ndpr_raf_onlink) {
  904                 int e;
  905 
  906                 if ((e = nd6_prefix_onlink(new)) != 0) {
  907                         nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
  908                             "the prefix %s/%d on-link on %s (errno=%d)\n",
  909                             ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
  910                             pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  911                         /* proceed anyway. XXX: is it correct? */
  912                 }
  913         }
  914 
  915         if (dr)
  916                 pfxrtr_add(new, dr);
  917 
  918         return 0;
  919 }
  920 
  921 void
  922 prelist_remove(struct nd_prefix *pr)
  923 {
  924         struct nd_pfxrouter *pfr, *next;
  925         int e, s;
  926 
  927         /* make sure to invalidate the prefix until it is really freed. */
  928         pr->ndpr_vltime = 0;
  929         pr->ndpr_pltime = 0;
  930 #if 0
  931         /*
  932          * Though these flags are now meaningless, we'd rather keep the value
  933          * not to confuse users when executing "ndp -p".
  934          */
  935         pr->ndpr_raf_onlink = 0;
  936         pr->ndpr_raf_auto = 0;
  937 #endif
  938         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
  939             (e = nd6_prefix_offlink(pr)) != 0) {
  940                 nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
  941                     "on %s, errno=%d\n",
  942                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
  943                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  944                 /* what should we do? */
  945         }
  946 
  947         if (pr->ndpr_refcnt > 0)
  948                 return;         /* notice here? */
  949 
  950         s = splsoftnet();
  951         /* unlink ndpr_entry from nd_prefix list */
  952         LIST_REMOVE(pr, ndpr_entry);
  953 
  954         /* free list of routers that adversed the prefix */
  955         for (pfr = LIST_FIRST(&pr->ndpr_advrtrs); pfr != NULL; pfr = next) {
  956                 next = LIST_NEXT(pfr, pfr_entry);
  957 
  958                 free(pfr, M_IP6NDP);
  959         }
  960         splx(s);
  961 
  962         free(pr, M_IP6NDP);
  963 
  964         pfxlist_onlink_check();
  965 }
  966 
  967 static int
  968 prelist_update(struct nd_prefixctl *new, 
  969         struct nd_defrouter *dr, /* may be NULL */
  970         struct mbuf *m, 
  971         int mcast)
  972 {
  973         struct in6_ifaddr *ia6 = NULL, *ia6_match = NULL;
  974         struct ifaddr *ifa;
  975         struct ifnet *ifp = new->ndpr_ifp;
  976         struct nd_prefix *pr;
  977         int s = splsoftnet();
  978         int error = 0;
  979         int newprefix = 0;
  980         int auth;
  981         struct in6_addrlifetime lt6_tmp;
  982 
  983         auth = 0;
  984         if (m) {
  985                 /*
  986                  * Authenticity for NA consists authentication for
  987                  * both IP header and IP datagrams, doesn't it ?
  988                  */
  989 #if defined(M_AUTHIPHDR) && defined(M_AUTHIPDGM)
  990                 auth = (m->m_flags & M_AUTHIPHDR
  991                      && m->m_flags & M_AUTHIPDGM) ? 1 : 0;
  992 #endif
  993         }
  994 
  995         if ((pr = nd6_prefix_lookup(new)) != NULL) {
  996                 /*
  997                  * nd6_prefix_lookup() ensures that pr and new have the same
  998                  * prefix on a same interface.
  999                  */
 1000 
 1001                 /*
 1002                  * Update prefix information.  Note that the on-link (L) bit
 1003                  * and the autonomous (A) bit should NOT be changed from 1
 1004                  * to 0.
 1005                  */
 1006                 if (new->ndpr_raf_onlink == 1)
 1007                         pr->ndpr_raf_onlink = 1;
 1008                 if (new->ndpr_raf_auto == 1)
 1009                         pr->ndpr_raf_auto = 1;
 1010                 if (new->ndpr_raf_onlink) {
 1011                         pr->ndpr_vltime = new->ndpr_vltime;
 1012                         pr->ndpr_pltime = new->ndpr_pltime;
 1013                         (void)in6_init_prefix_ltimes(pr); /* XXX error case? */
 1014                         pr->ndpr_lastupdate = time_second;
 1015                 }
 1016 
 1017                 if (new->ndpr_raf_onlink &&
 1018                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1019                         int e;
 1020 
 1021                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1022                                 nd6log((LOG_ERR,
 1023                                     "prelist_update: failed to make "
 1024                                     "the prefix %s/%d on-link on %s "
 1025                                     "(errno=%d)\n",
 1026                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1027                                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
 1028                                 /* proceed anyway. XXX: is it correct? */
 1029                         }
 1030                 }
 1031 
 1032                 if (dr && pfxrtr_lookup(pr, dr) == NULL)
 1033                         pfxrtr_add(pr, dr);
 1034         } else {
 1035                 struct nd_prefix *newpr = NULL;
 1036 
 1037                 newprefix = 1;
 1038 
 1039                 if (new->ndpr_vltime == 0)
 1040                         goto end;
 1041                 if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
 1042                         goto end;
 1043 
 1044                 error = nd6_prelist_add(new, dr, &newpr);
 1045                 if (error != 0 || newpr == NULL) {
 1046                         nd6log((LOG_NOTICE, "prelist_update: "
 1047                             "nd6_prelist_add failed for %s/%d on %s "
 1048                             "errno=%d, returnpr=%p\n",
 1049                             ip6_sprintf(&new->ndpr_prefix.sin6_addr),
 1050                             new->ndpr_plen, if_name(new->ndpr_ifp),
 1051                             error, newpr));
 1052                         goto end; /* we should just give up in this case. */
 1053                 }
 1054 
 1055                 /*
 1056                  * XXX: from the ND point of view, we can ignore a prefix
 1057                  * with the on-link bit being zero.  However, we need a
 1058                  * prefix structure for references from autoconfigured
 1059                  * addresses.  Thus, we explicitly make sure that the prefix
 1060                  * itself expires now.
 1061                  */
 1062                 if (newpr->ndpr_raf_onlink == 0) {
 1063                         newpr->ndpr_vltime = 0;
 1064                         newpr->ndpr_pltime = 0;
 1065                         in6_init_prefix_ltimes(newpr);
 1066                 }
 1067 
 1068                 pr = newpr;
 1069         }
 1070 
 1071         /*
 1072          * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
 1073          * Note that pr must be non NULL at this point.
 1074          */
 1075 
 1076         /* 5.5.3 (a). Ignore the prefix without the A bit set. */
 1077         if (!new->ndpr_raf_auto)
 1078                 goto end;
 1079 
 1080         /*
 1081          * 5.5.3 (b). the link-local prefix should have been ignored in
 1082          * nd6_ra_input.
 1083          */
 1084 
 1085         /* 5.5.3 (c). Consistency check on lifetimes: pltime <= vltime. */
 1086         if (new->ndpr_pltime > new->ndpr_vltime) {
 1087                 error = EINVAL; /* XXX: won't be used */
 1088                 goto end;
 1089         }
 1090 
 1091         /*
 1092          * 5.5.3 (d).  If the prefix advertised is not equal to the prefix of
 1093          * an address configured by stateless autoconfiguration already in the
 1094          * list of addresses associated with the interface, and the Valid
 1095          * Lifetime is not 0, form an address.  We first check if we have
 1096          * a matching prefix.
 1097          * Note: we apply a clarification in rfc2462bis-02 here.  We only
 1098          * consider autoconfigured addresses while RFC2462 simply said
 1099          * "address".
 1100          */
 1101         IFADDR_FOREACH(ifa, ifp) {
 1102                 struct in6_ifaddr *ifa6;
 1103                 u_int32_t remaininglifetime;
 1104 
 1105                 if (ifa->ifa_addr->sa_family != AF_INET6)
 1106                         continue;
 1107 
 1108                 ifa6 = (struct in6_ifaddr *)ifa;
 1109 
 1110                 /*
 1111                  * We only consider autoconfigured addresses as per rfc2462bis.
 1112                  */
 1113                 if (!(ifa6->ia6_flags & IN6_IFF_AUTOCONF))
 1114                         continue;
 1115 
 1116                 /*
 1117                  * Spec is not clear here, but I believe we should concentrate
 1118                  * on unicast (i.e. not anycast) addresses.
 1119                  * XXX: other ia6_flags? detached or duplicated?
 1120                  */
 1121                 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0)
 1122                         continue;
 1123 
 1124                 /*
 1125                  * Ignore the address if it is not associated with a prefix
 1126                  * or is associated with a prefix that is different from this
 1127                  * one.  (pr is never NULL here)
 1128                  */
 1129                 if (ifa6->ia6_ndpr != pr)
 1130                         continue;
 1131 
 1132                 if (ia6_match == NULL) /* remember the first one */
 1133                         ia6_match = ifa6;
 1134 
 1135                 /*
 1136                  * An already autoconfigured address matched.  Now that we
 1137                  * are sure there is at least one matched address, we can
 1138                  * proceed to 5.5.3. (e): update the lifetimes according to the
 1139                  * "two hours" rule and the privacy extension.
 1140                  * We apply some clarifications in rfc2462bis:
 1141                  * - use remaininglifetime instead of storedlifetime as a
 1142                  *   variable name
 1143                  * - remove the dead code in the "two-hour" rule
 1144                  */
 1145 #define TWOHOUR         (120*60)
 1146                 lt6_tmp = ifa6->ia6_lifetime;
 1147                 if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME)
 1148                         remaininglifetime = ND6_INFINITE_LIFETIME;
 1149                 else if (time_second - ifa6->ia6_updatetime >
 1150                          lt6_tmp.ia6t_vltime) {
 1151                         /*
 1152                          * The case of "invalid" address.  We should usually
 1153                          * not see this case.
 1154                          */
 1155                         remaininglifetime = 0;
 1156                 } else
 1157                         remaininglifetime = lt6_tmp.ia6t_vltime -
 1158                             (time_second - ifa6->ia6_updatetime);
 1159 
 1160                 /* when not updating, keep the current stored lifetime. */
 1161                 lt6_tmp.ia6t_vltime = remaininglifetime;
 1162 
 1163                 if (TWOHOUR < new->ndpr_vltime ||
 1164                     remaininglifetime < new->ndpr_vltime) {
 1165                         lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1166                 } else if (remaininglifetime <= TWOHOUR) {
 1167                         if (auth)
 1168                                 lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1169                 } else {
 1170                         /*
 1171                          * new->ndpr_vltime <= TWOHOUR &&
 1172                          * TWOHOUR < remaininglifetime
 1173                          */
 1174                         lt6_tmp.ia6t_vltime = TWOHOUR;
 1175                 }
 1176 
 1177                 /* The 2 hour rule is not imposed for preferred lifetime. */
 1178                 lt6_tmp.ia6t_pltime = new->ndpr_pltime;
 1179 
 1180                 in6_init_address_ltimes(pr, &lt6_tmp);
 1181 
 1182                 /*
 1183                  * We need to treat lifetimes for temporary addresses
 1184                  * differently, according to
 1185                  * draft-ietf-ipv6-privacy-addrs-v2-01.txt 3.3 (1);
 1186                  * we only update the lifetimes when they are in the maximum
 1187                  * intervals.
 1188                  */
 1189                 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0) {
 1190                         u_int32_t maxvltime, maxpltime;
 1191 
 1192                         if (ip6_temp_valid_lifetime >
 1193                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1194                             ip6_desync_factor)) {
 1195                                 maxvltime = ip6_temp_valid_lifetime -
 1196                                     (time_second - ifa6->ia6_createtime) -
 1197                                     ip6_desync_factor;
 1198                         } else
 1199                                 maxvltime = 0;
 1200                         if (ip6_temp_preferred_lifetime >
 1201                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1202                             ip6_desync_factor)) {
 1203                                 maxpltime = ip6_temp_preferred_lifetime -
 1204                                     (time_second - ifa6->ia6_createtime) -
 1205                                     ip6_desync_factor;
 1206                         } else
 1207                                 maxpltime = 0;
 1208 
 1209                         if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME ||
 1210                             lt6_tmp.ia6t_vltime > maxvltime) {
 1211                                 lt6_tmp.ia6t_vltime = maxvltime;
 1212                         }
 1213                         if (lt6_tmp.ia6t_pltime == ND6_INFINITE_LIFETIME ||
 1214                             lt6_tmp.ia6t_pltime > maxpltime) {
 1215                                 lt6_tmp.ia6t_pltime = maxpltime;
 1216                         }
 1217                 }
 1218 
 1219                 ifa6->ia6_lifetime = lt6_tmp;
 1220                 ifa6->ia6_updatetime = time_second;
 1221         }
 1222         if (ia6_match == NULL && new->ndpr_vltime) {
 1223                 int ifidlen;
 1224 
 1225                 /*
 1226                  * 5.5.3 (d) (continued)
 1227                  * No address matched and the valid lifetime is non-zero.
 1228                  * Create a new address.
 1229                  */
 1230 
 1231                 /*
 1232                  * Prefix Length check:
 1233                  * If the sum of the prefix length and interface identifier
 1234                  * length does not equal 128 bits, the Prefix Information
 1235                  * option MUST be ignored.  The length of the interface
 1236                  * identifier is defined in a separate link-type specific
 1237                  * document.
 1238                  */
 1239                 ifidlen = in6_if2idlen(ifp);
 1240                 if (ifidlen < 0) {
 1241                         /* this should not happen, so we always log it. */
 1242                         log(LOG_ERR, "prelist_update: IFID undefined (%s)\n",
 1243                             if_name(ifp));
 1244                         goto end;
 1245                 }
 1246                 if (ifidlen + pr->ndpr_plen != 128) {
 1247                         nd6log((LOG_INFO,
 1248                             "prelist_update: invalid prefixlen "
 1249                             "%d for %s, ignored\n",
 1250                             pr->ndpr_plen, if_name(ifp)));
 1251                         goto end;
 1252                 }
 1253 
 1254                 if ((ia6 = in6_ifadd(new, mcast)) != NULL) {
 1255                         /*
 1256                          * note that we should use pr (not new) for reference.
 1257                          */
 1258                         pr->ndpr_refcnt++;
 1259                         ia6->ia6_ndpr = pr;
 1260 
 1261                         /*
 1262                          * draft-ietf-ipngwg-temp-addresses-v2-00 3.3 (2).
 1263                          * When a new public address is created as described
 1264                          * in RFC2462, also create a new temporary address.
 1265                          *
 1266                          * draft-ietf-ipngwg-temp-addresses-v2-00 3.5.
 1267                          * When an interface connects to a new link, a new
 1268                          * randomized interface identifier should be generated
 1269                          * immediately together with a new set of temporary
 1270                          * addresses.  Thus, we specifiy 1 as the 2nd arg of
 1271                          * in6_tmpifadd().
 1272                          */
 1273                         if (ip6_use_tempaddr) {
 1274                                 int e;
 1275                                 if ((e = in6_tmpifadd(ia6, 1, 1)) != 0) {
 1276                                         nd6log((LOG_NOTICE, "prelist_update: "
 1277                                             "failed to create a temporary "
 1278                                             "address, errno=%d\n",
 1279                                             e));
 1280                                 }
 1281                         }
 1282 
 1283                         /*
 1284                          * A newly added address might affect the status
 1285                          * of other addresses, so we check and update it.
 1286                          * XXX: what if address duplication happens?
 1287                          */
 1288                         pfxlist_onlink_check();
 1289                 } else {
 1290                         /* just set an error. do not bark here. */
 1291                         error = EADDRNOTAVAIL; /* XXX: might be unused. */
 1292                 }
 1293         }
 1294 
 1295  end:
 1296         splx(s);
 1297         return error;
 1298 }
 1299 
 1300 /*
 1301  * A supplement function used in the on-link detection below;
 1302  * detect if a given prefix has a (probably) reachable advertising router.
 1303  * XXX: lengthy function name...
 1304  */
 1305 static struct nd_pfxrouter *
 1306 find_pfxlist_reachable_router(struct nd_prefix *pr)
 1307 {
 1308         struct nd_pfxrouter *pfxrtr;
 1309         struct rtentry *rt;
 1310         struct llinfo_nd6 *ln;
 1311 
 1312         for (pfxrtr = LIST_FIRST(&pr->ndpr_advrtrs); pfxrtr;
 1313              pfxrtr = LIST_NEXT(pfxrtr, pfr_entry)) {
 1314                 if ((rt = nd6_lookup(&pfxrtr->router->rtaddr, 0,
 1315                     pfxrtr->router->ifp)) &&
 1316                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
 1317                     ND6_IS_LLINFO_PROBREACH(ln))
 1318                         break;  /* found */
 1319         }
 1320 
 1321         return (pfxrtr);
 1322 }
 1323 
 1324 /*
 1325  * Check if each prefix in the prefix list has at least one available router
 1326  * that advertised the prefix (a router is "available" if its neighbor cache
 1327  * entry is reachable or probably reachable).
 1328  * If the check fails, the prefix may be off-link, because, for example,
 1329  * we have moved from the network but the lifetime of the prefix has not
 1330  * expired yet.  So we should not use the prefix if there is another prefix
 1331  * that has an available router.
 1332  * But, if there is no prefix that has an available router, we still regards
 1333  * all the prefixes as on-link.  This is because we can't tell if all the
 1334  * routers are simply dead or if we really moved from the network and there
 1335  * is no router around us.
 1336  */
 1337 void
 1338 pfxlist_onlink_check(void)
 1339 {
 1340         struct nd_prefix *pr;
 1341         struct in6_ifaddr *ifa;
 1342         struct nd_defrouter *dr;
 1343         struct nd_pfxrouter *pfxrtr = NULL;
 1344 
 1345         /*
 1346          * Check if there is a prefix that has a reachable advertising
 1347          * router.
 1348          */
 1349         LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1350                 if (pr->ndpr_raf_onlink && find_pfxlist_reachable_router(pr))
 1351                         break;
 1352         }
 1353         /*
 1354          * If we have no such prefix, check whether we still have a router
 1355          * that does not advertise any prefixes.
 1356          */
 1357         if (pr == NULL) {
 1358                 TAILQ_FOREACH(dr, &nd_defrouter, dr_entry) {
 1359                         struct nd_prefix *pr0;
 1360 
 1361                         LIST_FOREACH(pr0, &nd_prefix, ndpr_entry) {
 1362                                 if ((pfxrtr = pfxrtr_lookup(pr0, dr)) != NULL)
 1363                                         break;
 1364                         }
 1365                         if (pfxrtr)
 1366                                 break;
 1367                 }
 1368         }
 1369         if (pr != NULL || (TAILQ_FIRST(&nd_defrouter) && !pfxrtr)) {
 1370                 /*
 1371                  * There is at least one prefix that has a reachable router,
 1372                  * or at least a router which probably does not advertise
 1373                  * any prefixes.  The latter would be the case when we move
 1374                  * to a new link where we have a router that does not provide
 1375                  * prefixes and we configure an address by hand.
 1376                  * Detach prefixes which have no reachable advertising
 1377                  * router, and attach other prefixes.
 1378                  */
 1379                 LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1380                         /* XXX: a link-local prefix should never be detached */
 1381                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1382                                 continue;
 1383 
 1384                         /*
 1385                          * we aren't interested in prefixes without the L bit
 1386                          * set.
 1387                          */
 1388                         if (pr->ndpr_raf_onlink == 0)
 1389                                 continue;
 1390 
 1391                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1392                             find_pfxlist_reachable_router(pr) == NULL)
 1393                                 pr->ndpr_stateflags |= NDPRF_DETACHED;
 1394                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1395                             find_pfxlist_reachable_router(pr) != 0)
 1396                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1397                 }
 1398         } else {
 1399                 /* there is no prefix that has a reachable router */
 1400                 LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1401                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1402                                 continue;
 1403 
 1404                         if (pr->ndpr_raf_onlink == 0)
 1405                                 continue;
 1406 
 1407                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1408                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1409                 }
 1410         }
 1411 
 1412         /*
 1413          * Remove each interface route associated with a (just) detached
 1414          * prefix, and reinstall the interface route for a (just) attached
 1415          * prefix.  Note that all attempt of reinstallation does not
 1416          * necessarily success, when a same prefix is shared among multiple
 1417          * interfaces.  Such cases will be handled in nd6_prefix_onlink,
 1418          * so we don't have to care about them.
 1419          */
 1420         LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1421                 int e;
 1422 
 1423                 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1424                         continue;
 1425 
 1426                 if (pr->ndpr_raf_onlink == 0)
 1427                         continue;
 1428 
 1429                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1430                     (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1431                         if ((e = nd6_prefix_offlink(pr)) != 0) {
 1432                                 nd6log((LOG_ERR,
 1433                                     "pfxlist_onlink_check: failed to "
 1434                                     "make %s/%d offlink, errno=%d\n",
 1435                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1436                                     pr->ndpr_plen, e));
 1437                         }
 1438                 }
 1439                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1440                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0 &&
 1441                     pr->ndpr_raf_onlink) {
 1442                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1443                                 nd6log((LOG_ERR,
 1444                                     "pfxlist_onlink_check: failed to "
 1445                                     "make %s/%d onlink, errno=%d\n",
 1446                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1447                                     pr->ndpr_plen, e));
 1448                         }
 1449                 }
 1450         }
 1451 
 1452         /*
 1453          * Changes on the prefix status might affect address status as well.
 1454          * Make sure that all addresses derived from an attached prefix are
 1455          * attached, and that all addresses derived from a detached prefix are
 1456          * detached.  Note, however, that a manually configured address should
 1457          * always be attached.
 1458          * The precise detection logic is same as the one for prefixes.
 1459          */
 1460         for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1461                 if (!(ifa->ia6_flags & IN6_IFF_AUTOCONF))
 1462                         continue;
 1463 
 1464                 if (ifa->ia6_ndpr == NULL) {
 1465                         /*
 1466                          * This can happen when we first configure the address
 1467                          * (i.e. the address exists, but the prefix does not).
 1468                          * XXX: complicated relationships...
 1469                          */
 1470                         continue;
 1471                 }
 1472 
 1473                 if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
 1474                         break;
 1475         }
 1476         if (ifa) {
 1477                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1478                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1479                                 continue;
 1480 
 1481                         if (ifa->ia6_ndpr == NULL) /* XXX: see above. */
 1482                                 continue;
 1483 
 1484                         if (find_pfxlist_reachable_router(ifa->ia6_ndpr)) {
 1485                                 if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1486                                         ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1487                                         ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1488                                         nd6_dad_start((struct ifaddr *)ifa,
 1489                                             0);
 1490                                 }
 1491                         } else {
 1492                                 if ((ifa->ia6_flags & IN6_IFF_DETACHED) == 0) {
 1493                                         ifa->ia6_flags |= IN6_IFF_DETACHED;
 1494                                 }
 1495                         }
 1496                 }
 1497         }
 1498         else {
 1499                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1500                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1501                                 continue;
 1502 
 1503                         if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1504                                 ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1505                                 ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1506                                 /* Do we need a delay in this case? */
 1507                                 nd6_dad_start((struct ifaddr *)ifa, 0);
 1508                         }
 1509                 }
 1510         }
 1511 }
 1512 
 1513 int
 1514 nd6_prefix_onlink(struct nd_prefix *pr)
 1515 {
 1516         struct ifaddr *ifa;
 1517         struct ifnet *ifp = pr->ndpr_ifp;
 1518         struct sockaddr_in6 mask6;
 1519         struct nd_prefix *opr;
 1520         u_long rtflags;
 1521         int error = 0;
 1522         struct rtentry *rt = NULL;
 1523 
 1524         /* sanity check */
 1525         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1526                 nd6log((LOG_ERR,
 1527                     "nd6_prefix_onlink: %s/%d is already on-link\n",
 1528                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen));
 1529                 return (EEXIST);
 1530         }
 1531 
 1532         /*
 1533          * Add the interface route associated with the prefix.  Before
 1534          * installing the route, check if there's the same prefix on another
 1535          * interface, and the prefix has already installed the interface route.
 1536          * Although such a configuration is expected to be rare, we explicitly
 1537          * allow it.
 1538          */
 1539         LIST_FOREACH(opr, &nd_prefix, ndpr_entry) {
 1540                 if (opr == pr)
 1541                         continue;
 1542 
 1543                 if ((opr->ndpr_stateflags & NDPRF_ONLINK) == 0)
 1544                         continue;
 1545 
 1546                 if (opr->ndpr_plen == pr->ndpr_plen &&
 1547                     in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1548                     &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen))
 1549                         return (0);
 1550         }
 1551 
 1552         /*
 1553          * We prefer link-local addresses as the associated interface address.
 1554          */
 1555         /* search for a link-local addr */
 1556         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
 1557             IN6_IFF_NOTREADY | IN6_IFF_ANYCAST);
 1558         if (ifa == NULL) {
 1559                 /* XXX: freebsd does not have ifa_ifwithaf */
 1560                 IFADDR_FOREACH(ifa, ifp) {
 1561                         if (ifa->ifa_addr->sa_family == AF_INET6)
 1562                                 break;
 1563                 }
 1564                 /* should we care about ia6_flags? */
 1565         }
 1566         if (ifa == NULL) {
 1567                 /*
 1568                  * This can still happen, when, for example, we receive an RA
 1569                  * containing a prefix with the L bit set and the A bit clear,
 1570                  * after removing all IPv6 addresses on the receiving
 1571                  * interface.  This should, of course, be rare though.
 1572                  */
 1573                 nd6log((LOG_NOTICE,
 1574                     "nd6_prefix_onlink: failed to find any ifaddr"
 1575                     " to add route for a prefix(%s/%d) on %s\n",
 1576                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1577                     pr->ndpr_plen, if_name(ifp)));
 1578                 return (0);
 1579         }
 1580 
 1581         /*
 1582          * in6_ifinit() sets nd6_rtrequest to ifa_rtrequest for all ifaddrs.
 1583          * ifa->ifa_rtrequest = nd6_rtrequest;
 1584          */
 1585         bzero(&mask6, sizeof(mask6));
 1586         mask6.sin6_len = sizeof(mask6);
 1587         mask6.sin6_addr = pr->ndpr_mask;
 1588         /* rtrequest() will probably set RTF_UP, but we're not sure. */
 1589         rtflags = ifa->ifa_flags | RTF_UP;
 1590         if (nd6_need_cache(ifp)) {
 1591                 /* explicitly set in case ifa_flags does not set the flag. */
 1592                 rtflags |= RTF_CLONING;
 1593         } else {
 1594                 /*
 1595                  * explicitly clear the cloning bit in case ifa_flags sets it.
 1596                  */
 1597                 rtflags &= ~RTF_CLONING;
 1598         }
 1599         error = rtrequest(RTM_ADD, (struct sockaddr *)&pr->ndpr_prefix,
 1600             ifa->ifa_addr, (struct sockaddr *)&mask6, rtflags, &rt);
 1601         if (error == 0) {
 1602                 if (rt != NULL) /* this should be non NULL, though */
 1603                         nd6_rtmsg(RTM_ADD, rt);
 1604                 pr->ndpr_stateflags |= NDPRF_ONLINK;
 1605         } else {
 1606                 nd6log((LOG_ERR, "nd6_prefix_onlink: failed to add route for a"
 1607                     " prefix (%s/%d) on %s, gw=%s, mask=%s, flags=%lx "
 1608                     "errno = %d\n",
 1609                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1610                     pr->ndpr_plen, if_name(ifp),
 1611                     ip6_sprintf(&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr),
 1612                     ip6_sprintf(&mask6.sin6_addr), rtflags, error));
 1613         }
 1614 
 1615         if (rt != NULL)
 1616                 rt->rt_refcnt--;
 1617 
 1618         return (error);
 1619 }
 1620 
 1621 int
 1622 nd6_prefix_offlink(struct nd_prefix *pr)
 1623 {
 1624         int error = 0;
 1625         struct ifnet *ifp = pr->ndpr_ifp;
 1626         struct nd_prefix *opr;
 1627         struct sockaddr_in6 sa6, mask6;
 1628         struct rtentry *rt = NULL;
 1629 
 1630         /* sanity check */
 1631         if ((pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1632                 nd6log((LOG_ERR,
 1633                     "nd6_prefix_offlink: %s/%d is already off-link\n",
 1634                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen));
 1635                 return (EEXIST);
 1636         }
 1637 
 1638         sockaddr_in6_init(&sa6, &pr->ndpr_prefix.sin6_addr, 0, 0, 0);
 1639         sockaddr_in6_init(&mask6, &pr->ndpr_mask, 0, 0, 0);
 1640         error = rtrequest(RTM_DELETE, (struct sockaddr *)&sa6, NULL,
 1641             (struct sockaddr *)&mask6, 0, &rt);
 1642         if (error == 0) {
 1643                 pr->ndpr_stateflags &= ~NDPRF_ONLINK;
 1644 
 1645                 /* report the route deletion to the routing socket. */
 1646                 if (rt != NULL)
 1647                         nd6_rtmsg(RTM_DELETE, rt);
 1648 
 1649                 /*
 1650                  * There might be the same prefix on another interface,
 1651                  * the prefix which could not be on-link just because we have
 1652                  * the interface route (see comments in nd6_prefix_onlink).
 1653                  * If there's one, try to make the prefix on-link on the
 1654                  * interface.
 1655                  */
 1656                 LIST_FOREACH(opr, &nd_prefix, ndpr_entry) {
 1657                         if (opr == pr)
 1658                                 continue;
 1659 
 1660                         if ((opr->ndpr_stateflags & NDPRF_ONLINK) != 0)
 1661                                 continue;
 1662 
 1663                         /*
 1664                          * KAME specific: detached prefixes should not be
 1665                          * on-link.
 1666                          */
 1667                         if ((opr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1668                                 continue;
 1669 
 1670                         if (opr->ndpr_plen == pr->ndpr_plen &&
 1671                             in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1672                             &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
 1673                                 int e;
 1674 
 1675                                 if ((e = nd6_prefix_onlink(opr)) != 0) {
 1676                                         nd6log((LOG_ERR,
 1677                                             "nd6_prefix_offlink: failed to "
 1678                                             "recover a prefix %s/%d from %s "
 1679                                             "to %s (errno = %d)\n",
 1680                                             ip6_sprintf(&opr->ndpr_prefix.sin6_addr),
 1681                                             opr->ndpr_plen, if_name(ifp),
 1682                                             if_name(opr->ndpr_ifp), e));
 1683                                 }
 1684                         }
 1685                 }
 1686         } else {
 1687                 /* XXX: can we still set the NDPRF_ONLINK flag? */
 1688                 nd6log((LOG_ERR,
 1689                     "nd6_prefix_offlink: failed to delete route: "
 1690                     "%s/%d on %s (errno = %d)\n",
 1691                     ip6_sprintf(&sa6.sin6_addr), pr->ndpr_plen, if_name(ifp),
 1692                     error));
 1693         }
 1694 
 1695         if (rt != NULL) {
 1696                 if (rt->rt_refcnt <= 0) {
 1697                         /* XXX: we should free the entry ourselves. */
 1698                         rt->rt_refcnt++;
 1699                         rtfree(rt);
 1700                 }
 1701         }
 1702 
 1703         return (error);
 1704 }
 1705 
 1706 static struct in6_ifaddr *
 1707 in6_ifadd(struct nd_prefixctl *pr, int mcast)
 1708 {
 1709         struct ifnet *ifp = pr->ndpr_ifp;
 1710         struct ifaddr *ifa;
 1711         struct in6_aliasreq ifra;
 1712         struct in6_ifaddr *ia, *ib;
 1713         int error, plen0;
 1714         struct in6_addr mask;
 1715         int prefixlen = pr->ndpr_plen;
 1716         int updateflags;
 1717 
 1718         in6_prefixlen2mask(&mask, prefixlen);
 1719 
 1720         /*
 1721          * find a link-local address (will be interface ID).
 1722          * Is it really mandatory? Theoretically, a global or a site-local
 1723          * address can be configured without a link-local address, if we
 1724          * have a unique interface identifier...
 1725          *
 1726          * it is not mandatory to have a link-local address, we can generate
 1727          * interface identifier on the fly.  we do this because:
 1728          * (1) it should be the easiest way to find interface identifier.
 1729          * (2) RFC2462 5.4 suggesting the use of the same interface identifier
 1730          * for multiple addresses on a single interface, and possible shortcut
 1731          * of DAD.  we omitted DAD for this reason in the past.
 1732          * (3) a user can prevent autoconfiguration of global address
 1733          * by removing link-local address by hand (this is partly because we
 1734          * don't have other way to control the use of IPv6 on an interface.
 1735          * this has been our design choice - cf. NRL's "ifconfig auto").
 1736          * (4) it is easier to manage when an interface has addresses
 1737          * with the same interface identifier, than to have multiple addresses
 1738          * with different interface identifiers.
 1739          */
 1740         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0); /* 0 is OK? */
 1741         if (ifa)
 1742                 ib = (struct in6_ifaddr *)ifa;
 1743         else
 1744                 return NULL;
 1745 
 1746 #if 0 /* don't care link local addr state, and always do DAD */
 1747         /* if link-local address is not eligible, do not autoconfigure. */
 1748         if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY) {
 1749                 printf("in6_ifadd: link-local address not ready\n");
 1750                 return NULL;
 1751         }
 1752 #endif
 1753 
 1754         /* prefixlen + ifidlen must be equal to 128 */
 1755         plen0 = in6_mask2len(&ib->ia_prefixmask.sin6_addr, NULL);
 1756         if (prefixlen != plen0) {
 1757                 nd6log((LOG_INFO, "in6_ifadd: wrong prefixlen for %s "
 1758                     "(prefix=%d ifid=%d)\n",
 1759                     if_name(ifp), prefixlen, 128 - plen0));
 1760                 return NULL;
 1761         }
 1762 
 1763         /* make ifaddr */
 1764 
 1765         memset(&ifra, 0, sizeof(ifra));
 1766         /*
 1767          * in6_update_ifa() does not use ifra_name, but we accurately set it
 1768          * for safety.
 1769          */
 1770         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1771         sockaddr_in6_init(&ifra.ifra_addr, &pr->ndpr_prefix.sin6_addr, 0, 0, 0);
 1772         /* prefix */
 1773         ifra.ifra_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
 1774         ifra.ifra_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
 1775         ifra.ifra_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
 1776         ifra.ifra_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
 1777 
 1778         /* interface ID */
 1779         ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
 1780             (ib->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
 1781         ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
 1782             (ib->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
 1783         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1784             (ib->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
 1785         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1786             (ib->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);
 1787 
 1788         /* new prefix mask. */
 1789         sockaddr_in6_init(&ifra.ifra_prefixmask, &mask, 0, 0, 0);
 1790 
 1791         /* lifetimes */
 1792         ifra.ifra_lifetime.ia6t_vltime = pr->ndpr_vltime;
 1793         ifra.ifra_lifetime.ia6t_pltime = pr->ndpr_pltime;
 1794 
 1795         /* XXX: scope zone ID? */
 1796 
 1797         ifra.ifra_flags |= IN6_IFF_AUTOCONF; /* obey autoconf */
 1798 
 1799         /*
 1800          * Make sure that we do not have this address already.  This should
 1801          * usually not happen, but we can still see this case, e.g., if we
 1802          * have manually configured the exact address to be configured.
 1803          */
 1804         if (in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr) != NULL) {
 1805                 /* this should be rare enough to make an explicit log */
 1806                 log(LOG_INFO, "in6_ifadd: %s is already configured\n",
 1807                     ip6_sprintf(&ifra.ifra_addr.sin6_addr));
 1808                 return (NULL);
 1809         }
 1810 
 1811         /*
 1812          * Allocate ifaddr structure, link into chain, etc.
 1813          * If we are going to create a new address upon receiving a multicasted
 1814          * RA, we need to impose a random delay before starting DAD.
 1815          * [draft-ietf-ipv6-rfc2462bis-02.txt, Section 5.4.2]
 1816          */
 1817         updateflags = 0;
 1818         if (mcast)
 1819                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1820         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0) {
 1821                 nd6log((LOG_ERR,
 1822                     "in6_ifadd: failed to make ifaddr %s on %s (errno=%d)\n",
 1823                     ip6_sprintf(&ifra.ifra_addr.sin6_addr), if_name(ifp),
 1824                     error));
 1825                 return (NULL);  /* ifaddr must not have been allocated. */
 1826         }
 1827 
 1828         ia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1829 
 1830         return (ia);            /* this is always non-NULL */
 1831 }
 1832 
 1833 int
 1834 in6_tmpifadd(
 1835         const struct in6_ifaddr *ia0, /* corresponding public address */
 1836         int forcegen, 
 1837         int dad_delay)
 1838 {
 1839         struct ifnet *ifp = ia0->ia_ifa.ifa_ifp;
 1840         struct in6_ifaddr *newia, *ia;
 1841         struct in6_aliasreq ifra;
 1842         int i, error;
 1843         int trylimit = 3;       /* XXX: adhoc value */
 1844         int updateflags;
 1845         u_int32_t randid[2];
 1846         u_int32_t vltime0, pltime0;
 1847 
 1848         memset(&ifra, 0, sizeof(ifra));
 1849         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1850         ifra.ifra_addr = ia0->ia_addr;
 1851         /* copy prefix mask */
 1852         ifra.ifra_prefixmask = ia0->ia_prefixmask;
 1853         /* clear the old IFID */
 1854         for (i = 0; i < 4; i++) {
 1855                 ifra.ifra_addr.sin6_addr.s6_addr32[i] &=
 1856                     ifra.ifra_prefixmask.sin6_addr.s6_addr32[i];
 1857         }
 1858 
 1859   again:
 1860         if (in6_get_tmpifid(ifp, (u_int8_t *)randid,
 1861             (const u_int8_t *)&ia0->ia_addr.sin6_addr.s6_addr[8], forcegen)) {
 1862                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to find a good "
 1863                     "random IFID\n"));
 1864                 return (EINVAL);
 1865         }
 1866         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1867             (randid[0] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[2]));
 1868         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1869             (randid[1] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[3]));
 1870 
 1871         /*
 1872          * in6_get_tmpifid() quite likely provided a unique interface ID.
 1873          * However, we may still have a chance to see collision, because
 1874          * there may be a time lag between generation of the ID and generation
 1875          * of the address.  So, we'll do one more sanity check.
 1876          */
 1877         for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
 1878                 if (IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
 1879                     &ifra.ifra_addr.sin6_addr)) {
 1880                         if (trylimit-- == 0) {
 1881                                 /*
 1882                                  * Give up.  Something strange should have
 1883                                  * happened.
 1884                                  */
 1885                                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to "
 1886                                     "find a unique random IFID\n"));
 1887                                 return (EEXIST);
 1888                         }
 1889                         forcegen = 1;
 1890                         goto again;
 1891                 }
 1892         }
 1893 
 1894         /*
 1895          * The Valid Lifetime is the lower of the Valid Lifetime of the
 1896          * public address or TEMP_VALID_LIFETIME.
 1897          * The Preferred Lifetime is the lower of the Preferred Lifetime
 1898          * of the public address or TEMP_PREFERRED_LIFETIME -
 1899          * DESYNC_FACTOR.
 1900          */
 1901         if (ia0->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
 1902                 vltime0 = IFA6_IS_INVALID(ia0) ? 0 :
 1903                     (ia0->ia6_lifetime.ia6t_vltime -
 1904                     (time_second - ia0->ia6_updatetime));
 1905                 if (vltime0 > ip6_temp_valid_lifetime)
 1906                         vltime0 = ip6_temp_valid_lifetime;
 1907         } else
 1908                 vltime0 = ip6_temp_valid_lifetime;
 1909         if (ia0->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
 1910                 pltime0 = IFA6_IS_DEPRECATED(ia0) ? 0 :
 1911                     (ia0->ia6_lifetime.ia6t_pltime -
 1912                     (time_second - ia0->ia6_updatetime));
 1913                 if (pltime0 > ip6_temp_preferred_lifetime - ip6_desync_factor){
 1914                         pltime0 = ip6_temp_preferred_lifetime -
 1915                             ip6_desync_factor;
 1916                 }
 1917         } else
 1918                 pltime0 = ip6_temp_preferred_lifetime - ip6_desync_factor;
 1919         ifra.ifra_lifetime.ia6t_vltime = vltime0;
 1920         ifra.ifra_lifetime.ia6t_pltime = pltime0;
 1921 
 1922         /*
 1923          * A temporary address is created only if this calculated Preferred
 1924          * Lifetime is greater than REGEN_ADVANCE time units.
 1925          */
 1926         if (ifra.ifra_lifetime.ia6t_pltime <= ip6_temp_regen_advance)
 1927                 return (0);
 1928 
 1929         /* XXX: scope zone ID? */
 1930 
 1931         ifra.ifra_flags |= (IN6_IFF_AUTOCONF|IN6_IFF_TEMPORARY);
 1932 
 1933         /* allocate ifaddr structure, link into chain, etc. */
 1934         updateflags = 0;
 1935         if (dad_delay)
 1936                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1937         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0)
 1938                 return (error);
 1939 
 1940         newia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1941         if (newia == NULL) {    /* XXX: can it happen? */
 1942                 nd6log((LOG_ERR,
 1943                     "in6_tmpifadd: ifa update succeeded, but we got "
 1944                     "no ifaddr\n"));
 1945                 return (EINVAL); /* XXX */
 1946         }
 1947         newia->ia6_ndpr = ia0->ia6_ndpr;
 1948         newia->ia6_ndpr->ndpr_refcnt++;
 1949 
 1950         /*
 1951          * A newly added address might affect the status of other addresses.
 1952          * XXX: when the temporary address is generated with a new public
 1953          * address, the onlink check is redundant.  However, it would be safe
 1954          * to do the check explicitly everywhere a new address is generated,
 1955          * and, in fact, we surely need the check when we create a new
 1956          * temporary address due to deprecation of an old temporary address.
 1957          */
 1958         pfxlist_onlink_check();
 1959 
 1960         return (0);
 1961 }
 1962 
 1963 static int
 1964 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
 1965 {
 1966 
 1967         /* check if preferred lifetime > valid lifetime.  RFC2462 5.5.3 (c) */
 1968         if (ndpr->ndpr_pltime > ndpr->ndpr_vltime) {
 1969                 nd6log((LOG_INFO, "in6_init_prefix_ltimes: preferred lifetime"
 1970                     "(%d) is greater than valid lifetime(%d)\n",
 1971                     (u_int)ndpr->ndpr_pltime, (u_int)ndpr->ndpr_vltime));
 1972                 return (EINVAL);
 1973         }
 1974         if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
 1975                 ndpr->ndpr_preferred = 0;
 1976         else
 1977                 ndpr->ndpr_preferred = time_second + ndpr->ndpr_pltime;
 1978         if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
 1979                 ndpr->ndpr_expire = 0;
 1980         else
 1981                 ndpr->ndpr_expire = time_second + ndpr->ndpr_vltime;
 1982 
 1983         return 0;
 1984 }
 1985 
 1986 static void
 1987 in6_init_address_ltimes(struct nd_prefix *new,
 1988     struct in6_addrlifetime *lt6)
 1989 {
 1990 
 1991         /* Valid lifetime must not be updated unless explicitly specified. */
 1992         /* init ia6t_expire */
 1993         if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
 1994                 lt6->ia6t_expire = 0;
 1995         else {
 1996                 lt6->ia6t_expire = time_second;
 1997                 lt6->ia6t_expire += lt6->ia6t_vltime;
 1998         }
 1999 
 2000         /* init ia6t_preferred */
 2001         if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
 2002                 lt6->ia6t_preferred = 0;
 2003         else {
 2004                 lt6->ia6t_preferred = time_second;
 2005                 lt6->ia6t_preferred += lt6->ia6t_pltime;
 2006         }
 2007 }
 2008 
 2009 /*
 2010  * Delete all the routing table entries that use the specified gateway.
 2011  * XXX: this function causes search through all entries of routing table, so
 2012  * it shouldn't be called when acting as a router.
 2013  */
 2014 void
 2015 rt6_flush(struct in6_addr *gateway, struct ifnet *ifp)
 2016 {
 2017         int s = splsoftnet();
 2018 
 2019         /* We'll care only link-local addresses */
 2020         if (!IN6_IS_ADDR_LINKLOCAL(gateway)) {
 2021                 splx(s);
 2022                 return;
 2023         }
 2024 
 2025         rt_walktree(AF_INET6, rt6_deleteroute, (void *)gateway);
 2026         splx(s);
 2027 }
 2028 
 2029 static int
 2030 rt6_deleteroute(struct rtentry *rt, void *arg)
 2031 {
 2032 #define SIN6(s) ((struct sockaddr_in6 *)s)
 2033         struct in6_addr *gate = (struct in6_addr *)arg;
 2034 
 2035         if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
 2036                 return (0);
 2037 
 2038         if (!IN6_ARE_ADDR_EQUAL(gate, &SIN6(rt->rt_gateway)->sin6_addr))
 2039                 return (0);
 2040 
 2041         /*
 2042          * Do not delete a static route.
 2043          * XXX: this seems to be a bit ad-hoc. Should we consider the
 2044          * 'cloned' bit instead?
 2045          */
 2046         if ((rt->rt_flags & RTF_STATIC) != 0)
 2047                 return (0);
 2048 
 2049         /*
 2050          * We delete only host route. This means, in particular, we don't
 2051          * delete default route.
 2052          */
 2053         if ((rt->rt_flags & RTF_HOST) == 0)
 2054                 return (0);
 2055 
 2056         return (rtrequest(RTM_DELETE, rt_getkey(rt), rt->rt_gateway,
 2057             rt_mask(rt), rt->rt_flags, 0));
 2058 #undef SIN6
 2059 }
 2060 
 2061 int
 2062 nd6_setdefaultiface(int ifindex)
 2063 {
 2064         int error = 0;
 2065 
 2066         if (ifindex < 0 || if_indexlim <= ifindex)
 2067                 return (EINVAL);
 2068         if (ifindex != 0 && !ifindex2ifnet[ifindex])
 2069                 return (EINVAL);
 2070 
 2071         if (nd6_defifindex != ifindex) {
 2072                 nd6_defifindex = ifindex;
 2073                 if (nd6_defifindex > 0) {
 2074                         nd6_defifp = ifindex2ifnet[nd6_defifindex];
 2075                 } else
 2076                         nd6_defifp = NULL;
 2077 
 2078                 /*
 2079                  * Our current implementation assumes one-to-one maping between
 2080                  * interfaces and links, so it would be natural to use the
 2081                  * default interface as the default link.
 2082                  */
 2083                 scope6_setdefault(nd6_defifp);
 2084         }
 2085 
 2086         return (error);
 2087 }

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