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 1.80 2009/11/06 20:41:22 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 1.80 2009/11/06 20:41:22 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 nd_ifinfo *ndi = ND_IFINFO(ifp);
  117         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  118         struct nd_router_solicit *nd_rs;
  119         struct in6_addr saddr6 = ip6->ip6_src;
  120         char *lladdr = NULL;
  121         int lladdrlen = 0;
  122         union nd_opts ndopts;
  123 
  124         /* If I'm not a router, ignore it. */
  125         if (nd6_accepts_rtadv(ndi) || !ip6_forwarding)
  126                 goto freeit;
  127 
  128         /* Sanity checks */
  129         if (ip6->ip6_hlim != 255) {
  130                 nd6log((LOG_ERR,
  131                     "nd6_rs_input: invalid hlim (%d) from %s to %s on %s\n",
  132                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  133                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  134                 goto bad;
  135         }
  136 
  137         /*
  138          * Don't update the neighbor cache, if src = ::.
  139          * This indicates that the src has no IP address assigned yet.
  140          */
  141         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  142                 goto freeit;
  143 
  144         IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
  145         if (nd_rs == NULL) {
  146                 ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
  147                 return;
  148         }
  149 
  150         icmp6len -= sizeof(*nd_rs);
  151         nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
  152         if (nd6_options(&ndopts) < 0) {
  153                 nd6log((LOG_INFO,
  154                     "nd6_rs_input: invalid ND option, ignored\n"));
  155                 /* nd6_options have incremented stats */
  156                 goto freeit;
  157         }
  158 
  159         if (ndopts.nd_opts_src_lladdr) {
  160                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  161                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  162         }
  163 
  164         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  165                 nd6log((LOG_INFO,
  166                     "nd6_rs_input: lladdrlen mismatch for %s "
  167                     "(if %d, RS packet %d)\n",
  168                     ip6_sprintf(&saddr6), ifp->if_addrlen, lladdrlen - 2));
  169                 goto bad;
  170         }
  171 
  172         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
  173 
  174  freeit:
  175         m_freem(m);
  176         return;
  177 
  178  bad:
  179         ICMP6_STATINC(ICMP6_STAT_BADRS);
  180         m_freem(m);
  181 }
  182 
  183 /*
  184  * Receive Router Advertisement Message.
  185  *
  186  * Based on RFC 2461
  187  * TODO: on-link bit on prefix information
  188  * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
  189  */
  190 void
  191 nd6_ra_input(struct mbuf *m, int off, int icmp6len)
  192 {
  193         struct ifnet *ifp = m->m_pkthdr.rcvif;
  194         struct nd_ifinfo *ndi = ND_IFINFO(ifp);
  195         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  196         struct nd_router_advert *nd_ra;
  197         struct in6_addr saddr6 = ip6->ip6_src;
  198 #if 0
  199         struct in6_addr daddr6 = ip6->ip6_dst;
  200         int flags; /* = nd_ra->nd_ra_flags_reserved; */
  201         int is_managed = ((flags & ND_RA_FLAG_MANAGED) != 0);
  202         int is_other = ((flags & ND_RA_FLAG_OTHER) != 0);
  203 #endif
  204         int mcast = 0;
  205         union nd_opts ndopts;
  206         struct nd_defrouter *dr;
  207 
  208         /*
  209          * We only accept RAs only when
  210          * the system-wide variable allows the acceptance, and
  211          * per-interface variable allows RAs on the receiving interface.
  212          */
  213         if (!nd6_accepts_rtadv(ndi))
  214                 goto freeit;
  215 
  216         if (ip6->ip6_hlim != 255) {
  217                 nd6log((LOG_ERR,
  218                     "nd6_ra_input: invalid hlim (%d) from %s to %s on %s\n",
  219                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  220                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  221                 goto bad;
  222         }
  223 
  224         if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
  225                 nd6log((LOG_ERR,
  226                     "nd6_ra_input: src %s is not link-local\n",
  227                     ip6_sprintf(&saddr6)));
  228                 goto bad;
  229         }
  230 
  231         IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
  232         if (nd_ra == NULL) {
  233                 ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
  234                 return;
  235         }
  236 
  237         icmp6len -= sizeof(*nd_ra);
  238         nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
  239         if (nd6_options(&ndopts) < 0) {
  240                 nd6log((LOG_INFO,
  241                     "nd6_ra_input: invalid ND option, ignored\n"));
  242                 /* nd6_options have incremented stats */
  243                 goto freeit;
  244         }
  245 
  246     {
  247         struct nd_defrouter drtr;
  248         u_int32_t advreachable = nd_ra->nd_ra_reachable;
  249 
  250         /* remember if this is a multicasted advertisement */
  251         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
  252                 mcast = 1;
  253 
  254         memset(&drtr, 0, sizeof(drtr));
  255         drtr.rtaddr = saddr6;
  256         drtr.flags  = nd_ra->nd_ra_flags_reserved;
  257         drtr.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
  258         drtr.expire = time_second + drtr.rtlifetime;
  259         drtr.ifp = ifp;
  260         /* unspecified or not? (RFC 2461 6.3.4) */
  261         if (advreachable) {
  262                 NTOHL(advreachable);
  263                 if (advreachable <= MAX_REACHABLE_TIME &&
  264                     ndi->basereachable != advreachable) {
  265                         ndi->basereachable = advreachable;
  266                         ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
  267                         ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
  268                 }
  269         }
  270         if (nd_ra->nd_ra_retransmit)
  271                 ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
  272         if (nd_ra->nd_ra_curhoplimit)
  273                 ndi->chlim = nd_ra->nd_ra_curhoplimit;
  274         dr = defrtrlist_update(&drtr);
  275     }
  276 
  277         /*
  278          * prefix
  279          */
  280         if (ndopts.nd_opts_pi) {
  281                 struct nd_opt_hdr *pt;
  282                 struct nd_opt_prefix_info *pi = NULL;
  283                 struct nd_prefixctl pr;
  284 
  285                 for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
  286                      pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
  287                      pt = (struct nd_opt_hdr *)((char *)pt +
  288                                                 (pt->nd_opt_len << 3))) {
  289                         if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
  290                                 continue;
  291                         pi = (struct nd_opt_prefix_info *)pt;
  292 
  293                         if (pi->nd_opt_pi_len != 4) {
  294                                 nd6log((LOG_INFO,
  295                                     "nd6_ra_input: invalid option "
  296                                     "len %d for prefix information option, "
  297                                     "ignored\n", pi->nd_opt_pi_len));
  298                                 continue;
  299                         }
  300 
  301                         if (128 < pi->nd_opt_pi_prefix_len) {
  302                                 nd6log((LOG_INFO,
  303                                     "nd6_ra_input: invalid prefix "
  304                                     "len %d for prefix information option, "
  305                                     "ignored\n", pi->nd_opt_pi_prefix_len));
  306                                 continue;
  307                         }
  308 
  309                         if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
  310                          || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
  311                                 nd6log((LOG_INFO,
  312                                     "nd6_ra_input: invalid prefix "
  313                                     "%s, ignored\n",
  314                                     ip6_sprintf(&pi->nd_opt_pi_prefix)));
  315                                 continue;
  316                         }
  317 
  318                         memset(&pr, 0, sizeof(pr));
  319                         sockaddr_in6_init(&pr.ndpr_prefix,
  320                             &pi->nd_opt_pi_prefix, 0, 0, 0);
  321                         pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;
  322 
  323                         pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
  324                             ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
  325                         pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
  326                             ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
  327                         pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
  328                         pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
  329                         pr.ndpr_pltime = ntohl(pi->nd_opt_pi_preferred_time);
  330 
  331                         (void)prelist_update(&pr, dr, m, mcast);
  332                 }
  333         }
  334 
  335         /*
  336          * MTU
  337          */
  338         if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
  339                 u_long mtu;
  340                 u_long maxmtu;
  341 
  342                 mtu = ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
  343 
  344                 /* lower bound */
  345                 if (mtu < IPV6_MMTU) {
  346                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
  347                             "mtu=%lu sent from %s, ignoring\n",
  348                             mtu, ip6_sprintf(&ip6->ip6_src)));
  349                         goto skip;
  350                 }
  351 
  352                 /* upper bound */
  353                 maxmtu = (ndi->maxmtu && ndi->maxmtu < ifp->if_mtu)
  354                     ? ndi->maxmtu : ifp->if_mtu;
  355                 if (mtu <= maxmtu) {
  356                         int change = (ndi->linkmtu != mtu);
  357 
  358                         ndi->linkmtu = mtu;
  359                         if (change) /* in6_maxmtu may change */
  360                                 in6_setmaxmtu();
  361                 } else {
  362                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
  363                             "mtu=%lu sent from %s; "
  364                             "exceeds maxmtu %lu, ignoring\n",
  365                             mtu, ip6_sprintf(&ip6->ip6_src), maxmtu));
  366                 }
  367         }
  368 
  369  skip:
  370 
  371         /*
  372          * Source link layer address
  373          */
  374     {
  375         char *lladdr = NULL;
  376         int lladdrlen = 0;
  377 
  378         if (ndopts.nd_opts_src_lladdr) {
  379                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  380                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  381         }
  382 
  383         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  384                 nd6log((LOG_INFO,
  385                     "nd6_ra_input: lladdrlen mismatch for %s "
  386                     "(if %d, RA packet %d)\n", ip6_sprintf(&saddr6),
  387                     ifp->if_addrlen, lladdrlen - 2));
  388                 goto bad;
  389         }
  390 
  391         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_ADVERT, 0);
  392 
  393         /*
  394          * Installing a link-layer address might change the state of the
  395          * router's neighbor cache, which might also affect our on-link
  396          * detection of adveritsed prefixes.
  397          */
  398         pfxlist_onlink_check();
  399     }
  400 
  401  freeit:
  402         m_freem(m);
  403         return;
  404 
  405  bad:
  406         ICMP6_STATINC(ICMP6_STAT_BADRA);
  407         m_freem(m);
  408 }
  409 
  410 /*
  411  * default router list processing sub routines
  412  */
  413 
  414 /* tell the change to user processes watching the routing socket. */
  415 static void
  416 nd6_rtmsg(int cmd, struct rtentry *rt)
  417 {
  418         struct rt_addrinfo info;
  419 
  420         memset((void *)&info, 0, sizeof(info));
  421         info.rti_info[RTAX_DST] = rt_getkey(rt);
  422         info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
  423         info.rti_info[RTAX_NETMASK] = rt_mask(rt);
  424         if (rt->rt_ifp) {
  425                 info.rti_info[RTAX_IFP] = rt->rt_ifp->if_dl->ifa_addr;
  426                 info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
  427         }
  428 
  429         rt_missmsg(cmd, &info, rt->rt_flags, 0);
  430 }
  431 
  432 void
  433 defrouter_addreq(struct nd_defrouter *new)
  434 {
  435         union {
  436                 struct sockaddr_in6 sin6;
  437                 struct sockaddr sa;
  438         } def, mask, gate;
  439         struct rtentry *newrt = NULL;
  440         int s;
  441         int error;
  442 
  443         memset(&def, 0, sizeof(def));
  444         memset(&mask, 0, sizeof(mask));
  445         memset(&gate, 0,sizeof(gate)); /* for safety */
  446 
  447         def.sin6.sin6_len = mask.sin6.sin6_len = gate.sin6.sin6_len =
  448             sizeof(struct sockaddr_in6);
  449         def.sin6.sin6_family = mask.sin6.sin6_family = gate.sin6.sin6_family = AF_INET6;
  450         gate.sin6.sin6_addr = new->rtaddr;
  451 #ifndef SCOPEDROUTING
  452         gate.sin6.sin6_scope_id = 0;    /* XXX */
  453 #endif
  454 
  455         s = splsoftnet();
  456         error = rtrequest(RTM_ADD, &def.sa, &gate.sa, &mask.sa,
  457             RTF_GATEWAY, &newrt);
  458         if (newrt) {
  459                 nd6_rtmsg(RTM_ADD, newrt); /* tell user process */
  460                 newrt->rt_refcnt--;
  461         }
  462         if (error == 0)
  463                 new->installed = 1;
  464         splx(s);
  465         return;
  466 }
  467 
  468 struct nd_defrouter *
  469 defrouter_lookup(const struct in6_addr *addr, struct ifnet *ifp)
  470 {
  471         struct nd_defrouter *dr;
  472 
  473         TAILQ_FOREACH(dr, &nd_defrouter, dr_entry) {
  474                 if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr))
  475                         break;
  476         }
  477 
  478         return dr;              /* search failed */
  479 }
  480 
  481 void
  482 defrtrlist_del(struct nd_defrouter *dr)
  483 {
  484         struct nd_ifinfo *ndi = ND_IFINFO(dr->ifp);
  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         /* XXX: better condition? */
  493         if (!ip6_forwarding && nd6_accepts_rtadv(ndi))
  494                 rt6_flush(&dr->rtaddr, dr->ifp);
  495 
  496         if (dr->installed) {
  497                 deldr = dr;
  498                 defrouter_delreq(dr);
  499         }
  500         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  501 
  502         /*
  503          * Also delete all the pointers to the router in each prefix lists.
  504          */
  505         LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
  506                 struct nd_pfxrouter *pfxrtr;
  507                 if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
  508                         pfxrtr_del(pfxrtr);
  509         }
  510         pfxlist_onlink_check();
  511 
  512         /*
  513          * If the router is the primary one, choose a new one.
  514          * Note that defrouter_select() will remove the current gateway
  515          * from the routing table.
  516          */
  517         if (deldr)
  518                 defrouter_select();
  519 
  520         free(dr, M_IP6NDP);
  521 }
  522 
  523 /*
  524  * Remove the default route for a given router.
  525  * This is just a subroutine function for defrouter_select(), and should
  526  * not be called from anywhere else.
  527  */
  528 static void
  529 defrouter_delreq(struct nd_defrouter *dr)
  530 {
  531         union {
  532                 struct sockaddr_in6 sin6;
  533                 struct sockaddr sa;
  534         } def, mask, gw;
  535         struct rtentry *oldrt = NULL;
  536 
  537 #ifdef DIAGNOSTIC
  538         if (dr == NULL)
  539                 panic("dr == NULL in defrouter_delreq");
  540 #endif
  541 
  542         memset(&def, 0, sizeof(def));
  543         memset(&mask, 0, sizeof(mask));
  544         memset(&gw, 0, sizeof(gw));     /* for safety */
  545 
  546         def.sin6.sin6_len = mask.sin6.sin6_len = gw.sin6.sin6_len =
  547             sizeof(struct sockaddr_in6);
  548         def.sin6.sin6_family = mask.sin6.sin6_family = gw.sin6.sin6_family = AF_INET6;
  549         gw.sin6.sin6_addr = dr->rtaddr;
  550 #ifndef SCOPEDROUTING
  551         gw.sin6.sin6_scope_id = 0;      /* XXX */
  552 #endif
  553 
  554         rtrequest(RTM_DELETE, &def.sa, &gw.sa, &mask.sa, RTF_GATEWAY, &oldrt);
  555         if (oldrt) {
  556                 nd6_rtmsg(RTM_DELETE, oldrt);
  557                 if (oldrt->rt_refcnt <= 0) {
  558                         /*
  559                          * XXX: borrowed from the RTM_DELETE case of
  560                          * rtrequest().
  561                          */
  562                         oldrt->rt_refcnt++;
  563                         rtfree(oldrt);
  564                 }
  565         }
  566 
  567         dr->installed = 0;
  568 }
  569 
  570 /*
  571  * remove all default routes from default router list
  572  */
  573 void
  574 defrouter_reset(void)
  575 {
  576         struct nd_defrouter *dr;
  577 
  578         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  579              dr = TAILQ_NEXT(dr, dr_entry))
  580                 defrouter_delreq(dr);
  581 
  582         /*
  583          * XXX should we also nuke any default routers in the kernel, by
  584          * going through them by rtalloc1()?
  585          */
  586 }
  587 
  588 /*
  589  * Default Router Selection according to Section 6.3.6 of RFC 2461 and
  590  * draft-ietf-ipngwg-router-selection:
  591  * 1) Routers that are reachable or probably reachable should be preferred.
  592  *    If we have more than one (probably) reachable router, prefer ones
  593  *    with the highest router preference.
  594  * 2) When no routers on the list are known to be reachable or
  595  *    probably reachable, routers SHOULD be selected in a round-robin
  596  *    fashion, regardless of router preference values.
  597  * 3) If the Default Router List is empty, assume that all
  598  *    destinations are on-link.
  599  *
  600  * We assume nd_defrouter is sorted by router preference value.
  601  * Since the code below covers both with and without router preference cases,
  602  * we do not need to classify the cases by ifdef.
  603  *
  604  * At this moment, we do not try to install more than one default router,
  605  * even when the multipath routing is available, because we're not sure about
  606  * the benefits for stub hosts comparing to the risk of making the code
  607  * complicated and the possibility of introducing bugs.
  608  */
  609 void
  610 defrouter_select(void)
  611 {
  612         struct nd_ifinfo *ndi;
  613         int s = splsoftnet();
  614         struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
  615         struct rtentry *rt = NULL;
  616         struct llinfo_nd6 *ln = NULL;
  617 
  618         /*
  619          * This function should be called only when acting as an autoconfigured
  620          * host.  Although the remaining part of this function is not effective
  621          * if the node is not an autoconfigured host, we explicitly exclude
  622          * such cases here for safety.
  623          */
  624         if (ip6_forwarding) {
  625                 nd6log((LOG_WARNING,
  626                     "defrouter_select: called unexpectedly (forwarding=%d, "
  627                     "accept_rtadv=%d)\n", ip6_forwarding, ip6_accept_rtadv));
  628                 splx(s);
  629                 return;
  630         }
  631 
  632         /*
  633          * Let's handle easy case (3) first:
  634          * If default router list is empty, there's nothing to be done.
  635          */
  636         if (!TAILQ_FIRST(&nd_defrouter)) {
  637                 splx(s);
  638                 return;
  639         }
  640 
  641         /*
  642          * Search for a (probably) reachable router from the list.
  643          * We just pick up the first reachable one (if any), assuming that
  644          * the ordering rule of the list described in defrtrlist_update().
  645          */
  646         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  647              dr = TAILQ_NEXT(dr, dr_entry)) {
  648                 ndi = ND_IFINFO(dr->ifp);
  649                 if (nd6_accepts_rtadv(ndi))
  650                         continue;
  651 
  652                 if (selected_dr == NULL &&
  653                     (rt = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) != NULL &&
  654                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) != NULL &&
  655                     ND6_IS_LLINFO_PROBREACH(ln)) {
  656                         selected_dr = dr;
  657                 }
  658 
  659                 if (dr->installed && !installed_dr)
  660                         installed_dr = dr;
  661                 else if (dr->installed && installed_dr) {
  662                         /* this should not happen.  warn for diagnosis. */
  663                         log(LOG_ERR, "defrouter_select: more than one router"
  664                             " is installed\n");
  665                 }
  666         }
  667         /*
  668          * If none of the default routers was found to be reachable,
  669          * round-robin the list regardless of preference.
  670          * Otherwise, if we have an installed router, check if the selected
  671          * (reachable) router should really be preferred to the installed one.
  672          * We only prefer the new router when the old one is not reachable
  673          * or when the new one has a really higher preference value.
  674          */
  675         if (selected_dr == NULL) {
  676                 if (installed_dr == NULL || !TAILQ_NEXT(installed_dr, dr_entry))
  677                         selected_dr = TAILQ_FIRST(&nd_defrouter);
  678                 else
  679                         selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
  680         } else if (installed_dr &&
  681             (rt = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp)) &&
  682             (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
  683             ND6_IS_LLINFO_PROBREACH(ln) &&
  684             rtpref(selected_dr) <= rtpref(installed_dr)) {
  685                 selected_dr = installed_dr;
  686         }
  687 
  688         /*
  689          * If the selected router is different than the installed one,
  690          * remove the installed router and install the selected one.
  691          * Note that the selected router is never NULL here.
  692          */
  693         if (installed_dr != selected_dr) {
  694                 if (installed_dr)
  695                         defrouter_delreq(installed_dr);
  696                 defrouter_addreq(selected_dr);
  697         }
  698 
  699         splx(s);
  700         return;
  701 }
  702 
  703 /*
  704  * for default router selection
  705  * regards router-preference field as a 2-bit signed integer
  706  */
  707 static int
  708 rtpref(struct nd_defrouter *dr)
  709 {
  710         switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
  711         case ND_RA_FLAG_RTPREF_HIGH:
  712                 return (RTPREF_HIGH);
  713         case ND_RA_FLAG_RTPREF_MEDIUM:
  714         case ND_RA_FLAG_RTPREF_RSV:
  715                 return (RTPREF_MEDIUM);
  716         case ND_RA_FLAG_RTPREF_LOW:
  717                 return (RTPREF_LOW);
  718         default:
  719                 /*
  720                  * This case should never happen.  If it did, it would mean a
  721                  * serious bug of kernel internal.  We thus always bark here.
  722                  * Or, can we even panic?
  723                  */
  724                 log(LOG_ERR, "rtpref: impossible RA flag %x\n", dr->flags);
  725                 return (RTPREF_INVALID);
  726         }
  727         /* NOTREACHED */
  728 }
  729 
  730 static struct nd_defrouter *
  731 defrtrlist_update(struct nd_defrouter *new)
  732 {
  733         struct nd_defrouter *dr, *n;
  734         int s = splsoftnet();
  735 
  736         if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
  737                 /* entry exists */
  738                 if (new->rtlifetime == 0) {
  739                         defrtrlist_del(dr);
  740                         dr = NULL;
  741                 } else {
  742                         int oldpref = rtpref(dr);
  743 
  744                         /* override */
  745                         dr->flags = new->flags; /* xxx flag check */
  746                         dr->rtlifetime = new->rtlifetime;
  747                         dr->expire = new->expire;
  748 
  749                         /*
  750                          * If the preference does not change, there's no need
  751                          * to sort the entries.
  752                          */
  753                         if (rtpref(new) == oldpref) {
  754                                 splx(s);
  755                                 return (dr);
  756                         }
  757 
  758                         /*
  759                          * preferred router may be changed, so relocate
  760                          * this router.
  761                          * XXX: calling TAILQ_REMOVE directly is a bad manner.
  762                          * However, since defrtrlist_del() has many side
  763                          * effects, we intentionally do so here.
  764                          * defrouter_select() below will handle routing
  765                          * changes later.
  766                          */
  767                         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  768                         n = dr;
  769                         goto insert;
  770                 }
  771                 splx(s);
  772                 return (dr);
  773         }
  774 
  775         /* entry does not exist */
  776         if (new->rtlifetime == 0) {
  777                 splx(s);
  778                 return (NULL);
  779         }
  780 
  781         n = (struct nd_defrouter *)malloc(sizeof(*n), M_IP6NDP, M_NOWAIT);
  782         if (n == NULL) {
  783                 splx(s);
  784                 return (NULL);
  785         }
  786         memset(n, 0, sizeof(*n));
  787         *n = *new;
  788 
  789 insert:
  790         /*
  791          * Insert the new router in the Default Router List;
  792          * The Default Router List should be in the descending order
  793          * of router-preferece.  Routers with the same preference are
  794          * sorted in the arriving time order.
  795          */
  796 
  797         /* insert at the end of the group */
  798         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  799              dr = TAILQ_NEXT(dr, dr_entry)) {
  800                 if (rtpref(n) > rtpref(dr))
  801                         break;
  802         }
  803         if (dr)
  804                 TAILQ_INSERT_BEFORE(dr, n, dr_entry);
  805         else
  806                 TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);
  807 
  808         defrouter_select();
  809 
  810         splx(s);
  811 
  812         return (n);
  813 }
  814 
  815 static struct nd_pfxrouter *
  816 pfxrtr_lookup(struct nd_prefix *pr, struct nd_defrouter *dr)
  817 {
  818         struct nd_pfxrouter *search;
  819 
  820         LIST_FOREACH(search, &pr->ndpr_advrtrs, pfr_entry) {
  821                 if (search->router == dr)
  822                         break;
  823         }
  824 
  825         return (search);
  826 }
  827 
  828 static void
  829 pfxrtr_add(struct nd_prefix *pr, struct nd_defrouter *dr)
  830 {
  831         struct nd_pfxrouter *new;
  832 
  833         new = malloc(sizeof(*new), M_IP6NDP, M_NOWAIT|M_ZERO);
  834         if (new == NULL)
  835                 return;
  836         new->router = dr;
  837 
  838         LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
  839 
  840         pfxlist_onlink_check();
  841 }
  842 
  843 static void
  844 pfxrtr_del(struct nd_pfxrouter *pfr)
  845 {
  846         LIST_REMOVE(pfr, pfr_entry);
  847         free(pfr, M_IP6NDP);
  848 }
  849 
  850 struct nd_prefix *
  851 nd6_prefix_lookup(struct nd_prefixctl *key)
  852 {
  853         struct nd_prefix *search;
  854 
  855         LIST_FOREACH(search, &nd_prefix, ndpr_entry) {
  856                 if (key->ndpr_ifp == search->ndpr_ifp &&
  857                     key->ndpr_plen == search->ndpr_plen &&
  858                     in6_are_prefix_equal(&key->ndpr_prefix.sin6_addr,
  859                     &search->ndpr_prefix.sin6_addr, key->ndpr_plen)) {
  860                         break;
  861                 }
  862         }
  863 
  864         return (search);
  865 }
  866 
  867 int
  868 nd6_prelist_add(struct nd_prefixctl *pr, struct nd_defrouter *dr, 
  869         struct nd_prefix **newp)
  870 {
  871         struct nd_prefix *new = NULL;
  872         int i, s;
  873         int error;
  874 
  875         error = 0;
  876         new = malloc(sizeof(*new), M_IP6NDP, M_NOWAIT|M_ZERO);
  877         if (new == NULL)
  878                 return ENOMEM;
  879         new->ndpr_ifp = pr->ndpr_ifp;
  880         new->ndpr_prefix = pr->ndpr_prefix;
  881         new->ndpr_plen = pr->ndpr_plen;
  882         new->ndpr_vltime = pr->ndpr_vltime;
  883         new->ndpr_pltime = pr->ndpr_pltime;
  884         new->ndpr_flags = pr->ndpr_flags;
  885         if ((error = in6_init_prefix_ltimes(new)) != 0) {
  886                 free(new, M_IP6NDP);
  887                 return(error);
  888         }
  889         new->ndpr_lastupdate = time_second;
  890         if (newp != NULL)
  891                 *newp = new;
  892 
  893         /* initialization */
  894         LIST_INIT(&new->ndpr_advrtrs);
  895         in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
  896         /* make prefix in the canonical form */
  897         for (i = 0; i < 4; i++)
  898                 new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
  899                     new->ndpr_mask.s6_addr32[i];
  900 
  901         s = splsoftnet();
  902         /* link ndpr_entry to nd_prefix list */
  903         LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
  904         splx(s);
  905 
  906         /* ND_OPT_PI_FLAG_ONLINK processing */
  907         if (new->ndpr_raf_onlink) {
  908                 int e;
  909 
  910                 if ((e = nd6_prefix_onlink(new)) != 0) {
  911                         nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
  912                             "the prefix %s/%d on-link on %s (errno=%d)\n",
  913                             ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
  914                             pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  915                         /* proceed anyway. XXX: is it correct? */
  916                 }
  917         }
  918 
  919         if (dr)
  920                 pfxrtr_add(new, dr);
  921 
  922         return 0;
  923 }
  924 
  925 void
  926 prelist_remove(struct nd_prefix *pr)
  927 {
  928         struct nd_pfxrouter *pfr, *next;
  929         int e, s;
  930 
  931         /* make sure to invalidate the prefix until it is really freed. */
  932         pr->ndpr_vltime = 0;
  933         pr->ndpr_pltime = 0;
  934 #if 0
  935         /*
  936          * Though these flags are now meaningless, we'd rather keep the value
  937          * not to confuse users when executing "ndp -p".
  938          */
  939         pr->ndpr_raf_onlink = 0;
  940         pr->ndpr_raf_auto = 0;
  941 #endif
  942         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
  943             (e = nd6_prefix_offlink(pr)) != 0) {
  944                 nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
  945                     "on %s, errno=%d\n",
  946                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
  947                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  948                 /* what should we do? */
  949         }
  950 
  951         if (pr->ndpr_refcnt > 0)
  952                 return;         /* notice here? */
  953 
  954         s = splsoftnet();
  955         /* unlink ndpr_entry from nd_prefix list */
  956         LIST_REMOVE(pr, ndpr_entry);
  957 
  958         /* free list of routers that adversed the prefix */
  959         for (pfr = LIST_FIRST(&pr->ndpr_advrtrs); pfr != NULL; pfr = next) {
  960                 next = LIST_NEXT(pfr, pfr_entry);
  961 
  962                 free(pfr, M_IP6NDP);
  963         }
  964         splx(s);
  965 
  966         free(pr, M_IP6NDP);
  967 
  968         pfxlist_onlink_check();
  969 }
  970 
  971 static int
  972 prelist_update(struct nd_prefixctl *new, 
  973         struct nd_defrouter *dr, /* may be NULL */
  974         struct mbuf *m, 
  975         int mcast)
  976 {
  977         struct in6_ifaddr *ia6 = NULL, *ia6_match = NULL;
  978         struct ifaddr *ifa;
  979         struct ifnet *ifp = new->ndpr_ifp;
  980         struct nd_prefix *pr;
  981         int s = splsoftnet();
  982         int error = 0;
  983         int newprefix = 0;
  984         int auth;
  985         struct in6_addrlifetime lt6_tmp;
  986 
  987         auth = 0;
  988         if (m) {
  989                 /*
  990                  * Authenticity for NA consists authentication for
  991                  * both IP header and IP datagrams, doesn't it ?
  992                  */
  993 #if defined(M_AUTHIPHDR) && defined(M_AUTHIPDGM)
  994                 auth = (m->m_flags & M_AUTHIPHDR
  995                      && m->m_flags & M_AUTHIPDGM) ? 1 : 0;
  996 #endif
  997         }
  998 
  999         if ((pr = nd6_prefix_lookup(new)) != NULL) {
 1000                 /*
 1001                  * nd6_prefix_lookup() ensures that pr and new have the same
 1002                  * prefix on a same interface.
 1003                  */
 1004 
 1005                 /*
 1006                  * Update prefix information.  Note that the on-link (L) bit
 1007                  * and the autonomous (A) bit should NOT be changed from 1
 1008                  * to 0.
 1009                  */
 1010                 if (new->ndpr_raf_onlink == 1)
 1011                         pr->ndpr_raf_onlink = 1;
 1012                 if (new->ndpr_raf_auto == 1)
 1013                         pr->ndpr_raf_auto = 1;
 1014                 if (new->ndpr_raf_onlink) {
 1015                         pr->ndpr_vltime = new->ndpr_vltime;
 1016                         pr->ndpr_pltime = new->ndpr_pltime;
 1017                         (void)in6_init_prefix_ltimes(pr); /* XXX error case? */
 1018                         pr->ndpr_lastupdate = time_second;
 1019                 }
 1020 
 1021                 if (new->ndpr_raf_onlink &&
 1022                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1023                         int e;
 1024 
 1025                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1026                                 nd6log((LOG_ERR,
 1027                                     "prelist_update: failed to make "
 1028                                     "the prefix %s/%d on-link on %s "
 1029                                     "(errno=%d)\n",
 1030                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1031                                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
 1032                                 /* proceed anyway. XXX: is it correct? */
 1033                         }
 1034                 }
 1035 
 1036                 if (dr && pfxrtr_lookup(pr, dr) == NULL)
 1037                         pfxrtr_add(pr, dr);
 1038         } else {
 1039                 struct nd_prefix *newpr = NULL;
 1040 
 1041                 newprefix = 1;
 1042 
 1043                 if (new->ndpr_vltime == 0)
 1044                         goto end;
 1045                 if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
 1046                         goto end;
 1047 
 1048                 error = nd6_prelist_add(new, dr, &newpr);
 1049                 if (error != 0 || newpr == NULL) {
 1050                         nd6log((LOG_NOTICE, "prelist_update: "
 1051                             "nd6_prelist_add failed for %s/%d on %s "
 1052                             "errno=%d, returnpr=%p\n",
 1053                             ip6_sprintf(&new->ndpr_prefix.sin6_addr),
 1054                             new->ndpr_plen, if_name(new->ndpr_ifp),
 1055                             error, newpr));
 1056                         goto end; /* we should just give up in this case. */
 1057                 }
 1058 
 1059                 /*
 1060                  * XXX: from the ND point of view, we can ignore a prefix
 1061                  * with the on-link bit being zero.  However, we need a
 1062                  * prefix structure for references from autoconfigured
 1063                  * addresses.  Thus, we explicitly make sure that the prefix
 1064                  * itself expires now.
 1065                  */
 1066                 if (newpr->ndpr_raf_onlink == 0) {
 1067                         newpr->ndpr_vltime = 0;
 1068                         newpr->ndpr_pltime = 0;
 1069                         in6_init_prefix_ltimes(newpr);
 1070                 }
 1071 
 1072                 pr = newpr;
 1073         }
 1074 
 1075         /*
 1076          * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
 1077          * Note that pr must be non NULL at this point.
 1078          */
 1079 
 1080         /* 5.5.3 (a). Ignore the prefix without the A bit set. */
 1081         if (!new->ndpr_raf_auto)
 1082                 goto end;
 1083 
 1084         /*
 1085          * 5.5.3 (b). the link-local prefix should have been ignored in
 1086          * nd6_ra_input.
 1087          */
 1088 
 1089         /* 5.5.3 (c). Consistency check on lifetimes: pltime <= vltime. */
 1090         if (new->ndpr_pltime > new->ndpr_vltime) {
 1091                 error = EINVAL; /* XXX: won't be used */
 1092                 goto end;
 1093         }
 1094 
 1095         /*
 1096          * 5.5.3 (d).  If the prefix advertised is not equal to the prefix of
 1097          * an address configured by stateless autoconfiguration already in the
 1098          * list of addresses associated with the interface, and the Valid
 1099          * Lifetime is not 0, form an address.  We first check if we have
 1100          * a matching prefix.
 1101          * Note: we apply a clarification in rfc2462bis-02 here.  We only
 1102          * consider autoconfigured addresses while RFC2462 simply said
 1103          * "address".
 1104          */
 1105         IFADDR_FOREACH(ifa, ifp) {
 1106                 struct in6_ifaddr *ifa6;
 1107                 u_int32_t remaininglifetime;
 1108 
 1109                 if (ifa->ifa_addr->sa_family != AF_INET6)
 1110                         continue;
 1111 
 1112                 ifa6 = (struct in6_ifaddr *)ifa;
 1113 
 1114                 /*
 1115                  * We only consider autoconfigured addresses as per rfc2462bis.
 1116                  */
 1117                 if (!(ifa6->ia6_flags & IN6_IFF_AUTOCONF))
 1118                         continue;
 1119 
 1120                 /*
 1121                  * Spec is not clear here, but I believe we should concentrate
 1122                  * on unicast (i.e. not anycast) addresses.
 1123                  * XXX: other ia6_flags? detached or duplicated?
 1124                  */
 1125                 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0)
 1126                         continue;
 1127 
 1128                 /*
 1129                  * Ignore the address if it is not associated with a prefix
 1130                  * or is associated with a prefix that is different from this
 1131                  * one.  (pr is never NULL here)
 1132                  */
 1133                 if (ifa6->ia6_ndpr != pr)
 1134                         continue;
 1135 
 1136                 if (ia6_match == NULL) /* remember the first one */
 1137                         ia6_match = ifa6;
 1138 
 1139                 /*
 1140                  * An already autoconfigured address matched.  Now that we
 1141                  * are sure there is at least one matched address, we can
 1142                  * proceed to 5.5.3. (e): update the lifetimes according to the
 1143                  * "two hours" rule and the privacy extension.
 1144                  * We apply some clarifications in rfc2462bis:
 1145                  * - use remaininglifetime instead of storedlifetime as a
 1146                  *   variable name
 1147                  * - remove the dead code in the "two-hour" rule
 1148                  */
 1149 #define TWOHOUR         (120*60)
 1150                 lt6_tmp = ifa6->ia6_lifetime;
 1151                 if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME)
 1152                         remaininglifetime = ND6_INFINITE_LIFETIME;
 1153                 else if (time_second - ifa6->ia6_updatetime >
 1154                          lt6_tmp.ia6t_vltime) {
 1155                         /*
 1156                          * The case of "invalid" address.  We should usually
 1157                          * not see this case.
 1158                          */
 1159                         remaininglifetime = 0;
 1160                 } else
 1161                         remaininglifetime = lt6_tmp.ia6t_vltime -
 1162                             (time_second - ifa6->ia6_updatetime);
 1163 
 1164                 /* when not updating, keep the current stored lifetime. */
 1165                 lt6_tmp.ia6t_vltime = remaininglifetime;
 1166 
 1167                 if (TWOHOUR < new->ndpr_vltime ||
 1168                     remaininglifetime < new->ndpr_vltime) {
 1169                         lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1170                 } else if (remaininglifetime <= TWOHOUR) {
 1171                         if (auth)
 1172                                 lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1173                 } else {
 1174                         /*
 1175                          * new->ndpr_vltime <= TWOHOUR &&
 1176                          * TWOHOUR < remaininglifetime
 1177                          */
 1178                         lt6_tmp.ia6t_vltime = TWOHOUR;
 1179                 }
 1180 
 1181                 /* The 2 hour rule is not imposed for preferred lifetime. */
 1182                 lt6_tmp.ia6t_pltime = new->ndpr_pltime;
 1183 
 1184                 in6_init_address_ltimes(pr, &lt6_tmp);
 1185 
 1186                 /*
 1187                  * We need to treat lifetimes for temporary addresses
 1188                  * differently, according to
 1189                  * draft-ietf-ipv6-privacy-addrs-v2-01.txt 3.3 (1);
 1190                  * we only update the lifetimes when they are in the maximum
 1191                  * intervals.
 1192                  */
 1193                 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0) {
 1194                         u_int32_t maxvltime, maxpltime;
 1195 
 1196                         if (ip6_temp_valid_lifetime >
 1197                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1198                             ip6_desync_factor)) {
 1199                                 maxvltime = ip6_temp_valid_lifetime -
 1200                                     (time_second - ifa6->ia6_createtime) -
 1201                                     ip6_desync_factor;
 1202                         } else
 1203                                 maxvltime = 0;
 1204                         if (ip6_temp_preferred_lifetime >
 1205                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1206                             ip6_desync_factor)) {
 1207                                 maxpltime = ip6_temp_preferred_lifetime -
 1208                                     (time_second - ifa6->ia6_createtime) -
 1209                                     ip6_desync_factor;
 1210                         } else
 1211                                 maxpltime = 0;
 1212 
 1213                         if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME ||
 1214                             lt6_tmp.ia6t_vltime > maxvltime) {
 1215                                 lt6_tmp.ia6t_vltime = maxvltime;
 1216                         }
 1217                         if (lt6_tmp.ia6t_pltime == ND6_INFINITE_LIFETIME ||
 1218                             lt6_tmp.ia6t_pltime > maxpltime) {
 1219                                 lt6_tmp.ia6t_pltime = maxpltime;
 1220                         }
 1221                 }
 1222 
 1223                 ifa6->ia6_lifetime = lt6_tmp;
 1224                 ifa6->ia6_updatetime = time_second;
 1225         }
 1226         if (ia6_match == NULL && new->ndpr_vltime) {
 1227                 int ifidlen;
 1228 
 1229                 /*
 1230                  * 5.5.3 (d) (continued)
 1231                  * No address matched and the valid lifetime is non-zero.
 1232                  * Create a new address.
 1233                  */
 1234 
 1235                 /*
 1236                  * Prefix Length check:
 1237                  * If the sum of the prefix length and interface identifier
 1238                  * length does not equal 128 bits, the Prefix Information
 1239                  * option MUST be ignored.  The length of the interface
 1240                  * identifier is defined in a separate link-type specific
 1241                  * document.
 1242                  */
 1243                 ifidlen = in6_if2idlen(ifp);
 1244                 if (ifidlen < 0) {
 1245                         /* this should not happen, so we always log it. */
 1246                         log(LOG_ERR, "prelist_update: IFID undefined (%s)\n",
 1247                             if_name(ifp));
 1248                         goto end;
 1249                 }
 1250                 if (ifidlen + pr->ndpr_plen != 128) {
 1251                         nd6log((LOG_INFO,
 1252                             "prelist_update: invalid prefixlen "
 1253                             "%d for %s, ignored\n",
 1254                             pr->ndpr_plen, if_name(ifp)));
 1255                         goto end;
 1256                 }
 1257 
 1258                 if ((ia6 = in6_ifadd(new, mcast)) != NULL) {
 1259                         /*
 1260                          * note that we should use pr (not new) for reference.
 1261                          */
 1262                         pr->ndpr_refcnt++;
 1263                         ia6->ia6_ndpr = pr;
 1264 
 1265                         /*
 1266                          * draft-ietf-ipngwg-temp-addresses-v2-00 3.3 (2).
 1267                          * When a new public address is created as described
 1268                          * in RFC2462, also create a new temporary address.
 1269                          *
 1270                          * draft-ietf-ipngwg-temp-addresses-v2-00 3.5.
 1271                          * When an interface connects to a new link, a new
 1272                          * randomized interface identifier should be generated
 1273                          * immediately together with a new set of temporary
 1274                          * addresses.  Thus, we specifiy 1 as the 2nd arg of
 1275                          * in6_tmpifadd().
 1276                          */
 1277                         if (ip6_use_tempaddr) {
 1278                                 int e;
 1279                                 if ((e = in6_tmpifadd(ia6, 1, 1)) != 0) {
 1280                                         nd6log((LOG_NOTICE, "prelist_update: "
 1281                                             "failed to create a temporary "
 1282                                             "address, errno=%d\n",
 1283                                             e));
 1284                                 }
 1285                         }
 1286 
 1287                         /*
 1288                          * A newly added address might affect the status
 1289                          * of other addresses, so we check and update it.
 1290                          * XXX: what if address duplication happens?
 1291                          */
 1292                         pfxlist_onlink_check();
 1293                 } else {
 1294                         /* just set an error. do not bark here. */
 1295                         error = EADDRNOTAVAIL; /* XXX: might be unused. */
 1296                 }
 1297         }
 1298 
 1299  end:
 1300         splx(s);
 1301         return error;
 1302 }
 1303 
 1304 /*
 1305  * A supplement function used in the on-link detection below;
 1306  * detect if a given prefix has a (probably) reachable advertising router.
 1307  * XXX: lengthy function name...
 1308  */
 1309 static struct nd_pfxrouter *
 1310 find_pfxlist_reachable_router(struct nd_prefix *pr)
 1311 {
 1312         struct nd_pfxrouter *pfxrtr;
 1313         struct rtentry *rt;
 1314         struct llinfo_nd6 *ln;
 1315 
 1316         for (pfxrtr = LIST_FIRST(&pr->ndpr_advrtrs); pfxrtr;
 1317              pfxrtr = LIST_NEXT(pfxrtr, pfr_entry)) {
 1318                 if ((rt = nd6_lookup(&pfxrtr->router->rtaddr, 0,
 1319                     pfxrtr->router->ifp)) &&
 1320                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
 1321                     ND6_IS_LLINFO_PROBREACH(ln))
 1322                         break;  /* found */
 1323         }
 1324 
 1325         return (pfxrtr);
 1326 }
 1327 
 1328 /*
 1329  * Check if each prefix in the prefix list has at least one available router
 1330  * that advertised the prefix (a router is "available" if its neighbor cache
 1331  * entry is reachable or probably reachable).
 1332  * If the check fails, the prefix may be off-link, because, for example,
 1333  * we have moved from the network but the lifetime of the prefix has not
 1334  * expired yet.  So we should not use the prefix if there is another prefix
 1335  * that has an available router.
 1336  * But, if there is no prefix that has an available router, we still regards
 1337  * all the prefixes as on-link.  This is because we can't tell if all the
 1338  * routers are simply dead or if we really moved from the network and there
 1339  * is no router around us.
 1340  */
 1341 void
 1342 pfxlist_onlink_check(void)
 1343 {
 1344         struct nd_prefix *pr;
 1345         struct in6_ifaddr *ifa;
 1346         struct nd_defrouter *dr;
 1347         struct nd_pfxrouter *pfxrtr = NULL;
 1348 
 1349         /*
 1350          * Check if there is a prefix that has a reachable advertising
 1351          * router.
 1352          */
 1353         LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1354                 if (pr->ndpr_raf_onlink && find_pfxlist_reachable_router(pr))
 1355                         break;
 1356         }
 1357         /*
 1358          * If we have no such prefix, check whether we still have a router
 1359          * that does not advertise any prefixes.
 1360          */
 1361         if (pr == NULL) {
 1362                 TAILQ_FOREACH(dr, &nd_defrouter, dr_entry) {
 1363                         struct nd_prefix *pr0;
 1364 
 1365                         LIST_FOREACH(pr0, &nd_prefix, ndpr_entry) {
 1366                                 if ((pfxrtr = pfxrtr_lookup(pr0, dr)) != NULL)
 1367                                         break;
 1368                         }
 1369                         if (pfxrtr)
 1370                                 break;
 1371                 }
 1372         }
 1373         if (pr != NULL || (TAILQ_FIRST(&nd_defrouter) && !pfxrtr)) {
 1374                 /*
 1375                  * There is at least one prefix that has a reachable router,
 1376                  * or at least a router which probably does not advertise
 1377                  * any prefixes.  The latter would be the case when we move
 1378                  * to a new link where we have a router that does not provide
 1379                  * prefixes and we configure an address by hand.
 1380                  * Detach prefixes which have no reachable advertising
 1381                  * router, and attach other prefixes.
 1382                  */
 1383                 LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1384                         /* XXX: a link-local prefix should never be detached */
 1385                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1386                                 continue;
 1387 
 1388                         /*
 1389                          * we aren't interested in prefixes without the L bit
 1390                          * set.
 1391                          */
 1392                         if (pr->ndpr_raf_onlink == 0)
 1393                                 continue;
 1394 
 1395                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1396                             find_pfxlist_reachable_router(pr) == NULL)
 1397                                 pr->ndpr_stateflags |= NDPRF_DETACHED;
 1398                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1399                             find_pfxlist_reachable_router(pr) != 0)
 1400                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1401                 }
 1402         } else {
 1403                 /* there is no prefix that has a reachable router */
 1404                 LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1405                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1406                                 continue;
 1407 
 1408                         if (pr->ndpr_raf_onlink == 0)
 1409                                 continue;
 1410 
 1411                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1412                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1413                 }
 1414         }
 1415 
 1416         /*
 1417          * Remove each interface route associated with a (just) detached
 1418          * prefix, and reinstall the interface route for a (just) attached
 1419          * prefix.  Note that all attempt of reinstallation does not
 1420          * necessarily success, when a same prefix is shared among multiple
 1421          * interfaces.  Such cases will be handled in nd6_prefix_onlink,
 1422          * so we don't have to care about them.
 1423          */
 1424         LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1425                 int e;
 1426 
 1427                 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1428                         continue;
 1429 
 1430                 if (pr->ndpr_raf_onlink == 0)
 1431                         continue;
 1432 
 1433                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1434                     (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1435                         if ((e = nd6_prefix_offlink(pr)) != 0) {
 1436                                 nd6log((LOG_ERR,
 1437                                     "pfxlist_onlink_check: failed to "
 1438                                     "make %s/%d offlink, errno=%d\n",
 1439                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1440                                     pr->ndpr_plen, e));
 1441                         }
 1442                 }
 1443                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1444                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0 &&
 1445                     pr->ndpr_raf_onlink) {
 1446                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1447                                 nd6log((LOG_ERR,
 1448                                     "pfxlist_onlink_check: failed to "
 1449                                     "make %s/%d onlink, errno=%d\n",
 1450                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1451                                     pr->ndpr_plen, e));
 1452                         }
 1453                 }
 1454         }
 1455 
 1456         /*
 1457          * Changes on the prefix status might affect address status as well.
 1458          * Make sure that all addresses derived from an attached prefix are
 1459          * attached, and that all addresses derived from a detached prefix are
 1460          * detached.  Note, however, that a manually configured address should
 1461          * always be attached.
 1462          * The precise detection logic is same as the one for prefixes.
 1463          */
 1464         for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1465                 if (!(ifa->ia6_flags & IN6_IFF_AUTOCONF))
 1466                         continue;
 1467 
 1468                 if (ifa->ia6_ndpr == NULL) {
 1469                         /*
 1470                          * This can happen when we first configure the address
 1471                          * (i.e. the address exists, but the prefix does not).
 1472                          * XXX: complicated relationships...
 1473                          */
 1474                         continue;
 1475                 }
 1476 
 1477                 if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
 1478                         break;
 1479         }
 1480         if (ifa) {
 1481                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1482                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1483                                 continue;
 1484 
 1485                         if (ifa->ia6_ndpr == NULL) /* XXX: see above. */
 1486                                 continue;
 1487 
 1488                         if (find_pfxlist_reachable_router(ifa->ia6_ndpr)) {
 1489                                 if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1490                                         ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1491                                         ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1492                                         nd6_dad_start((struct ifaddr *)ifa,
 1493                                             0);
 1494                                 }
 1495                         } else {
 1496                                 if ((ifa->ia6_flags & IN6_IFF_DETACHED) == 0) {
 1497                                         ifa->ia6_flags |= IN6_IFF_DETACHED;
 1498                                 }
 1499                         }
 1500                 }
 1501         }
 1502         else {
 1503                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1504                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1505                                 continue;
 1506 
 1507                         if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1508                                 ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1509                                 ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1510                                 /* Do we need a delay in this case? */
 1511                                 nd6_dad_start((struct ifaddr *)ifa, 0);
 1512                         }
 1513                 }
 1514         }
 1515 }
 1516 
 1517 int
 1518 nd6_prefix_onlink(struct nd_prefix *pr)
 1519 {
 1520         struct ifaddr *ifa;
 1521         struct ifnet *ifp = pr->ndpr_ifp;
 1522         struct sockaddr_in6 mask6;
 1523         struct nd_prefix *opr;
 1524         u_long rtflags;
 1525         int error = 0;
 1526         struct rtentry *rt = NULL;
 1527 
 1528         /* sanity check */
 1529         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1530                 nd6log((LOG_ERR,
 1531                     "nd6_prefix_onlink: %s/%d is already on-link\n",
 1532                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen));
 1533                 return (EEXIST);
 1534         }
 1535 
 1536         /*
 1537          * Add the interface route associated with the prefix.  Before
 1538          * installing the route, check if there's the same prefix on another
 1539          * interface, and the prefix has already installed the interface route.
 1540          * Although such a configuration is expected to be rare, we explicitly
 1541          * allow it.
 1542          */
 1543         LIST_FOREACH(opr, &nd_prefix, ndpr_entry) {
 1544                 if (opr == pr)
 1545                         continue;
 1546 
 1547                 if ((opr->ndpr_stateflags & NDPRF_ONLINK) == 0)
 1548                         continue;
 1549 
 1550                 if (opr->ndpr_plen == pr->ndpr_plen &&
 1551                     in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1552                     &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen))
 1553                         return (0);
 1554         }
 1555 
 1556         /*
 1557          * We prefer link-local addresses as the associated interface address.
 1558          */
 1559         /* search for a link-local addr */
 1560         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
 1561             IN6_IFF_NOTREADY | IN6_IFF_ANYCAST);
 1562         if (ifa == NULL) {
 1563                 /* XXX: freebsd does not have ifa_ifwithaf */
 1564                 IFADDR_FOREACH(ifa, ifp) {
 1565                         if (ifa->ifa_addr->sa_family == AF_INET6)
 1566                                 break;
 1567                 }
 1568                 /* should we care about ia6_flags? */
 1569         }
 1570         if (ifa == NULL) {
 1571                 /*
 1572                  * This can still happen, when, for example, we receive an RA
 1573                  * containing a prefix with the L bit set and the A bit clear,
 1574                  * after removing all IPv6 addresses on the receiving
 1575                  * interface.  This should, of course, be rare though.
 1576                  */
 1577                 nd6log((LOG_NOTICE,
 1578                     "nd6_prefix_onlink: failed to find any ifaddr"
 1579                     " to add route for a prefix(%s/%d) on %s\n",
 1580                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1581                     pr->ndpr_plen, if_name(ifp)));
 1582                 return (0);
 1583         }
 1584 
 1585         /*
 1586          * in6_ifinit() sets nd6_rtrequest to ifa_rtrequest for all ifaddrs.
 1587          * ifa->ifa_rtrequest = nd6_rtrequest;
 1588          */
 1589         memset(&mask6, 0, sizeof(mask6));
 1590         mask6.sin6_len = sizeof(mask6);
 1591         mask6.sin6_addr = pr->ndpr_mask;
 1592         /* rtrequest() will probably set RTF_UP, but we're not sure. */
 1593         rtflags = ifa->ifa_flags | RTF_UP;
 1594         if (nd6_need_cache(ifp)) {
 1595                 /* explicitly set in case ifa_flags does not set the flag. */
 1596                 rtflags |= RTF_CLONING;
 1597         } else {
 1598                 /*
 1599                  * explicitly clear the cloning bit in case ifa_flags sets it.
 1600                  */
 1601                 rtflags &= ~RTF_CLONING;
 1602         }
 1603         error = rtrequest(RTM_ADD, (struct sockaddr *)&pr->ndpr_prefix,
 1604             ifa->ifa_addr, (struct sockaddr *)&mask6, rtflags, &rt);
 1605         if (error == 0) {
 1606                 if (rt != NULL) /* this should be non NULL, though */
 1607                         nd6_rtmsg(RTM_ADD, rt);
 1608                 pr->ndpr_stateflags |= NDPRF_ONLINK;
 1609         } else {
 1610                 nd6log((LOG_ERR, "nd6_prefix_onlink: failed to add route for a"
 1611                     " prefix (%s/%d) on %s, gw=%s, mask=%s, flags=%lx "
 1612                     "errno = %d\n",
 1613                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1614                     pr->ndpr_plen, if_name(ifp),
 1615                     ip6_sprintf(&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr),
 1616                     ip6_sprintf(&mask6.sin6_addr), rtflags, error));
 1617         }
 1618 
 1619         if (rt != NULL)
 1620                 rt->rt_refcnt--;
 1621 
 1622         return (error);
 1623 }
 1624 
 1625 int
 1626 nd6_prefix_offlink(struct nd_prefix *pr)
 1627 {
 1628         int error = 0;
 1629         struct ifnet *ifp = pr->ndpr_ifp;
 1630         struct nd_prefix *opr;
 1631         struct sockaddr_in6 sa6, mask6;
 1632         struct rtentry *rt = NULL;
 1633 
 1634         /* sanity check */
 1635         if ((pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1636                 nd6log((LOG_ERR,
 1637                     "nd6_prefix_offlink: %s/%d is already off-link\n",
 1638                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen));
 1639                 return (EEXIST);
 1640         }
 1641 
 1642         sockaddr_in6_init(&sa6, &pr->ndpr_prefix.sin6_addr, 0, 0, 0);
 1643         sockaddr_in6_init(&mask6, &pr->ndpr_mask, 0, 0, 0);
 1644         error = rtrequest(RTM_DELETE, (struct sockaddr *)&sa6, NULL,
 1645             (struct sockaddr *)&mask6, 0, &rt);
 1646         if (error == 0) {
 1647                 pr->ndpr_stateflags &= ~NDPRF_ONLINK;
 1648 
 1649                 /* report the route deletion to the routing socket. */
 1650                 if (rt != NULL)
 1651                         nd6_rtmsg(RTM_DELETE, rt);
 1652 
 1653                 /*
 1654                  * There might be the same prefix on another interface,
 1655                  * the prefix which could not be on-link just because we have
 1656                  * the interface route (see comments in nd6_prefix_onlink).
 1657                  * If there's one, try to make the prefix on-link on the
 1658                  * interface.
 1659                  */
 1660                 LIST_FOREACH(opr, &nd_prefix, ndpr_entry) {
 1661                         if (opr == pr)
 1662                                 continue;
 1663 
 1664                         if ((opr->ndpr_stateflags & NDPRF_ONLINK) != 0)
 1665                                 continue;
 1666 
 1667                         /*
 1668                          * KAME specific: detached prefixes should not be
 1669                          * on-link.
 1670                          */
 1671                         if ((opr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1672                                 continue;
 1673 
 1674                         if (opr->ndpr_plen == pr->ndpr_plen &&
 1675                             in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1676                             &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
 1677                                 int e;
 1678 
 1679                                 if ((e = nd6_prefix_onlink(opr)) != 0) {
 1680                                         nd6log((LOG_ERR,
 1681                                             "nd6_prefix_offlink: failed to "
 1682                                             "recover a prefix %s/%d from %s "
 1683                                             "to %s (errno = %d)\n",
 1684                                             ip6_sprintf(&opr->ndpr_prefix.sin6_addr),
 1685                                             opr->ndpr_plen, if_name(ifp),
 1686                                             if_name(opr->ndpr_ifp), e));
 1687                                 }
 1688                         }
 1689                 }
 1690         } else {
 1691                 /* XXX: can we still set the NDPRF_ONLINK flag? */
 1692                 nd6log((LOG_ERR,
 1693                     "nd6_prefix_offlink: failed to delete route: "
 1694                     "%s/%d on %s (errno = %d)\n",
 1695                     ip6_sprintf(&sa6.sin6_addr), pr->ndpr_plen, if_name(ifp),
 1696                     error));
 1697         }
 1698 
 1699         if (rt != NULL) {
 1700                 if (rt->rt_refcnt <= 0) {
 1701                         /* XXX: we should free the entry ourselves. */
 1702                         rt->rt_refcnt++;
 1703                         rtfree(rt);
 1704                 }
 1705         }
 1706 
 1707         return (error);
 1708 }
 1709 
 1710 static struct in6_ifaddr *
 1711 in6_ifadd(struct nd_prefixctl *pr, int mcast)
 1712 {
 1713         struct ifnet *ifp = pr->ndpr_ifp;
 1714         struct ifaddr *ifa;
 1715         struct in6_aliasreq ifra;
 1716         struct in6_ifaddr *ia, *ib;
 1717         int error, plen0;
 1718         struct in6_addr mask;
 1719         int prefixlen = pr->ndpr_plen;
 1720         int updateflags;
 1721 
 1722         in6_prefixlen2mask(&mask, prefixlen);
 1723 
 1724         /*
 1725          * find a link-local address (will be interface ID).
 1726          * Is it really mandatory? Theoretically, a global or a site-local
 1727          * address can be configured without a link-local address, if we
 1728          * have a unique interface identifier...
 1729          *
 1730          * it is not mandatory to have a link-local address, we can generate
 1731          * interface identifier on the fly.  we do this because:
 1732          * (1) it should be the easiest way to find interface identifier.
 1733          * (2) RFC2462 5.4 suggesting the use of the same interface identifier
 1734          * for multiple addresses on a single interface, and possible shortcut
 1735          * of DAD.  we omitted DAD for this reason in the past.
 1736          * (3) a user can prevent autoconfiguration of global address
 1737          * by removing link-local address by hand (this is partly because we
 1738          * don't have other way to control the use of IPv6 on an interface.
 1739          * this has been our design choice - cf. NRL's "ifconfig auto").
 1740          * (4) it is easier to manage when an interface has addresses
 1741          * with the same interface identifier, than to have multiple addresses
 1742          * with different interface identifiers.
 1743          */
 1744         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0); /* 0 is OK? */
 1745         if (ifa)
 1746                 ib = (struct in6_ifaddr *)ifa;
 1747         else
 1748                 return NULL;
 1749 
 1750 #if 0 /* don't care link local addr state, and always do DAD */
 1751         /* if link-local address is not eligible, do not autoconfigure. */
 1752         if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY) {
 1753                 printf("in6_ifadd: link-local address not ready\n");
 1754                 return NULL;
 1755         }
 1756 #endif
 1757 
 1758         /* prefixlen + ifidlen must be equal to 128 */
 1759         plen0 = in6_mask2len(&ib->ia_prefixmask.sin6_addr, NULL);
 1760         if (prefixlen != plen0) {
 1761                 nd6log((LOG_INFO, "in6_ifadd: wrong prefixlen for %s "
 1762                     "(prefix=%d ifid=%d)\n",
 1763                     if_name(ifp), prefixlen, 128 - plen0));
 1764                 return NULL;
 1765         }
 1766 
 1767         /* make ifaddr */
 1768 
 1769         memset(&ifra, 0, sizeof(ifra));
 1770         /*
 1771          * in6_update_ifa() does not use ifra_name, but we accurately set it
 1772          * for safety.
 1773          */
 1774         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1775         sockaddr_in6_init(&ifra.ifra_addr, &pr->ndpr_prefix.sin6_addr, 0, 0, 0);
 1776         /* prefix */
 1777         ifra.ifra_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
 1778         ifra.ifra_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
 1779         ifra.ifra_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
 1780         ifra.ifra_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
 1781 
 1782         /* interface ID */
 1783         ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
 1784             (ib->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
 1785         ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
 1786             (ib->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
 1787         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1788             (ib->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
 1789         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1790             (ib->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);
 1791 
 1792         /* new prefix mask. */
 1793         sockaddr_in6_init(&ifra.ifra_prefixmask, &mask, 0, 0, 0);
 1794 
 1795         /* lifetimes */
 1796         ifra.ifra_lifetime.ia6t_vltime = pr->ndpr_vltime;
 1797         ifra.ifra_lifetime.ia6t_pltime = pr->ndpr_pltime;
 1798 
 1799         /* XXX: scope zone ID? */
 1800 
 1801         ifra.ifra_flags |= IN6_IFF_AUTOCONF; /* obey autoconf */
 1802 
 1803         /*
 1804          * Make sure that we do not have this address already.  This should
 1805          * usually not happen, but we can still see this case, e.g., if we
 1806          * have manually configured the exact address to be configured.
 1807          */
 1808         if (in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr) != NULL) {
 1809                 /* this should be rare enough to make an explicit log */
 1810                 log(LOG_INFO, "in6_ifadd: %s is already configured\n",
 1811                     ip6_sprintf(&ifra.ifra_addr.sin6_addr));
 1812                 return (NULL);
 1813         }
 1814 
 1815         /*
 1816          * Allocate ifaddr structure, link into chain, etc.
 1817          * If we are going to create a new address upon receiving a multicasted
 1818          * RA, we need to impose a random delay before starting DAD.
 1819          * [draft-ietf-ipv6-rfc2462bis-02.txt, Section 5.4.2]
 1820          */
 1821         updateflags = 0;
 1822         if (mcast)
 1823                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1824         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0) {
 1825                 nd6log((LOG_ERR,
 1826                     "in6_ifadd: failed to make ifaddr %s on %s (errno=%d)\n",
 1827                     ip6_sprintf(&ifra.ifra_addr.sin6_addr), if_name(ifp),
 1828                     error));
 1829                 return (NULL);  /* ifaddr must not have been allocated. */
 1830         }
 1831 
 1832         ia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1833 
 1834         return (ia);            /* this is always non-NULL */
 1835 }
 1836 
 1837 int
 1838 in6_tmpifadd(
 1839         const struct in6_ifaddr *ia0, /* corresponding public address */
 1840         int forcegen, 
 1841         int dad_delay)
 1842 {
 1843         struct ifnet *ifp = ia0->ia_ifa.ifa_ifp;
 1844         struct in6_ifaddr *newia, *ia;
 1845         struct in6_aliasreq ifra;
 1846         int i, error;
 1847         int trylimit = 3;       /* XXX: adhoc value */
 1848         int updateflags;
 1849         u_int32_t randid[2];
 1850         u_int32_t vltime0, pltime0;
 1851 
 1852         memset(&ifra, 0, sizeof(ifra));
 1853         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1854         ifra.ifra_addr = ia0->ia_addr;
 1855         /* copy prefix mask */
 1856         ifra.ifra_prefixmask = ia0->ia_prefixmask;
 1857         /* clear the old IFID */
 1858         for (i = 0; i < 4; i++) {
 1859                 ifra.ifra_addr.sin6_addr.s6_addr32[i] &=
 1860                     ifra.ifra_prefixmask.sin6_addr.s6_addr32[i];
 1861         }
 1862 
 1863   again:
 1864         if (in6_get_tmpifid(ifp, (u_int8_t *)randid,
 1865             (const u_int8_t *)&ia0->ia_addr.sin6_addr.s6_addr[8], forcegen)) {
 1866                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to find a good "
 1867                     "random IFID\n"));
 1868                 return (EINVAL);
 1869         }
 1870         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1871             (randid[0] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[2]));
 1872         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1873             (randid[1] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[3]));
 1874 
 1875         /*
 1876          * in6_get_tmpifid() quite likely provided a unique interface ID.
 1877          * However, we may still have a chance to see collision, because
 1878          * there may be a time lag between generation of the ID and generation
 1879          * of the address.  So, we'll do one more sanity check.
 1880          */
 1881         for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
 1882                 if (IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
 1883                     &ifra.ifra_addr.sin6_addr)) {
 1884                         if (trylimit-- == 0) {
 1885                                 /*
 1886                                  * Give up.  Something strange should have
 1887                                  * happened.
 1888                                  */
 1889                                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to "
 1890                                     "find a unique random IFID\n"));
 1891                                 return (EEXIST);
 1892                         }
 1893                         forcegen = 1;
 1894                         goto again;
 1895                 }
 1896         }
 1897 
 1898         /*
 1899          * The Valid Lifetime is the lower of the Valid Lifetime of the
 1900          * public address or TEMP_VALID_LIFETIME.
 1901          * The Preferred Lifetime is the lower of the Preferred Lifetime
 1902          * of the public address or TEMP_PREFERRED_LIFETIME -
 1903          * DESYNC_FACTOR.
 1904          */
 1905         if (ia0->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
 1906                 vltime0 = IFA6_IS_INVALID(ia0) ? 0 :
 1907                     (ia0->ia6_lifetime.ia6t_vltime -
 1908                     (time_second - ia0->ia6_updatetime));
 1909                 if (vltime0 > ip6_temp_valid_lifetime)
 1910                         vltime0 = ip6_temp_valid_lifetime;
 1911         } else
 1912                 vltime0 = ip6_temp_valid_lifetime;
 1913         if (ia0->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
 1914                 pltime0 = IFA6_IS_DEPRECATED(ia0) ? 0 :
 1915                     (ia0->ia6_lifetime.ia6t_pltime -
 1916                     (time_second - ia0->ia6_updatetime));
 1917                 if (pltime0 > ip6_temp_preferred_lifetime - ip6_desync_factor){
 1918                         pltime0 = ip6_temp_preferred_lifetime -
 1919                             ip6_desync_factor;
 1920                 }
 1921         } else
 1922                 pltime0 = ip6_temp_preferred_lifetime - ip6_desync_factor;
 1923         ifra.ifra_lifetime.ia6t_vltime = vltime0;
 1924         ifra.ifra_lifetime.ia6t_pltime = pltime0;
 1925 
 1926         /*
 1927          * A temporary address is created only if this calculated Preferred
 1928          * Lifetime is greater than REGEN_ADVANCE time units.
 1929          */
 1930         if (ifra.ifra_lifetime.ia6t_pltime <= ip6_temp_regen_advance)
 1931                 return (0);
 1932 
 1933         /* XXX: scope zone ID? */
 1934 
 1935         ifra.ifra_flags |= (IN6_IFF_AUTOCONF|IN6_IFF_TEMPORARY);
 1936 
 1937         /* allocate ifaddr structure, link into chain, etc. */
 1938         updateflags = 0;
 1939         if (dad_delay)
 1940                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1941         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0)
 1942                 return (error);
 1943 
 1944         newia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1945         if (newia == NULL) {    /* XXX: can it happen? */
 1946                 nd6log((LOG_ERR,
 1947                     "in6_tmpifadd: ifa update succeeded, but we got "
 1948                     "no ifaddr\n"));
 1949                 return (EINVAL); /* XXX */
 1950         }
 1951         newia->ia6_ndpr = ia0->ia6_ndpr;
 1952         newia->ia6_ndpr->ndpr_refcnt++;
 1953 
 1954         /*
 1955          * A newly added address might affect the status of other addresses.
 1956          * XXX: when the temporary address is generated with a new public
 1957          * address, the onlink check is redundant.  However, it would be safe
 1958          * to do the check explicitly everywhere a new address is generated,
 1959          * and, in fact, we surely need the check when we create a new
 1960          * temporary address due to deprecation of an old temporary address.
 1961          */
 1962         pfxlist_onlink_check();
 1963 
 1964         return (0);
 1965 }
 1966 
 1967 static int
 1968 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
 1969 {
 1970 
 1971         /* check if preferred lifetime > valid lifetime.  RFC2462 5.5.3 (c) */
 1972         if (ndpr->ndpr_pltime > ndpr->ndpr_vltime) {
 1973                 nd6log((LOG_INFO, "in6_init_prefix_ltimes: preferred lifetime"
 1974                     "(%d) is greater than valid lifetime(%d)\n",
 1975                     (u_int)ndpr->ndpr_pltime, (u_int)ndpr->ndpr_vltime));
 1976                 return (EINVAL);
 1977         }
 1978         if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
 1979                 ndpr->ndpr_preferred = 0;
 1980         else
 1981                 ndpr->ndpr_preferred = time_second + ndpr->ndpr_pltime;
 1982         if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
 1983                 ndpr->ndpr_expire = 0;
 1984         else
 1985                 ndpr->ndpr_expire = time_second + ndpr->ndpr_vltime;
 1986 
 1987         return 0;
 1988 }
 1989 
 1990 static void
 1991 in6_init_address_ltimes(struct nd_prefix *new,
 1992     struct in6_addrlifetime *lt6)
 1993 {
 1994 
 1995         /* Valid lifetime must not be updated unless explicitly specified. */
 1996         /* init ia6t_expire */
 1997         if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
 1998                 lt6->ia6t_expire = 0;
 1999         else {
 2000                 lt6->ia6t_expire = time_second;
 2001                 lt6->ia6t_expire += lt6->ia6t_vltime;
 2002         }
 2003 
 2004         /* init ia6t_preferred */
 2005         if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
 2006                 lt6->ia6t_preferred = 0;
 2007         else {
 2008                 lt6->ia6t_preferred = time_second;
 2009                 lt6->ia6t_preferred += lt6->ia6t_pltime;
 2010         }
 2011 }
 2012 
 2013 /*
 2014  * Delete all the routing table entries that use the specified gateway.
 2015  * XXX: this function causes search through all entries of routing table, so
 2016  * it shouldn't be called when acting as a router.
 2017  */
 2018 void
 2019 rt6_flush(struct in6_addr *gateway, struct ifnet *ifp)
 2020 {
 2021         int s = splsoftnet();
 2022 
 2023         /* We'll care only link-local addresses */
 2024         if (!IN6_IS_ADDR_LINKLOCAL(gateway)) {
 2025                 splx(s);
 2026                 return;
 2027         }
 2028 
 2029         rt_walktree(AF_INET6, rt6_deleteroute, (void *)gateway);
 2030         splx(s);
 2031 }
 2032 
 2033 static int
 2034 rt6_deleteroute(struct rtentry *rt, void *arg)
 2035 {
 2036 #define SIN6(s) ((struct sockaddr_in6 *)s)
 2037         struct in6_addr *gate = (struct in6_addr *)arg;
 2038 
 2039         if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
 2040                 return (0);
 2041 
 2042         if (!IN6_ARE_ADDR_EQUAL(gate, &SIN6(rt->rt_gateway)->sin6_addr))
 2043                 return (0);
 2044 
 2045         /*
 2046          * Do not delete a static route.
 2047          * XXX: this seems to be a bit ad-hoc. Should we consider the
 2048          * 'cloned' bit instead?
 2049          */
 2050         if ((rt->rt_flags & RTF_STATIC) != 0)
 2051                 return (0);
 2052 
 2053         /*
 2054          * We delete only host route. This means, in particular, we don't
 2055          * delete default route.
 2056          */
 2057         if ((rt->rt_flags & RTF_HOST) == 0)
 2058                 return (0);
 2059 
 2060         return (rtrequest(RTM_DELETE, rt_getkey(rt), rt->rt_gateway,
 2061             rt_mask(rt), rt->rt_flags, 0));
 2062 #undef SIN6
 2063 }
 2064 
 2065 int
 2066 nd6_setdefaultiface(int ifindex)
 2067 {
 2068         int error = 0;
 2069 
 2070         if (ifindex < 0 || if_indexlim <= ifindex)
 2071                 return (EINVAL);
 2072         if (ifindex != 0 && !ifindex2ifnet[ifindex])
 2073                 return (EINVAL);
 2074 
 2075         if (nd6_defifindex != ifindex) {
 2076                 nd6_defifindex = ifindex;
 2077                 if (nd6_defifindex > 0) {
 2078                         nd6_defifp = ifindex2ifnet[nd6_defifindex];
 2079                 } else
 2080                         nd6_defifp = NULL;
 2081 
 2082                 /*
 2083                  * Our current implementation assumes one-to-one maping between
 2084                  * interfaces and links, so it would be natural to use the
 2085                  * default interface as the default link.
 2086                  */
 2087                 scope6_setdefault(nd6_defifp);
 2088         }
 2089 
 2090         return (error);
 2091 }

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