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 1.62 2006/11/20 04:34:16 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 1.62 2006/11/20 04:34:16 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/scope6_var.h>
   62 
   63 #include <net/net_osdep.h>
   64 
   65 #define SDL(s)  ((struct sockaddr_dl *)s)
   66 
   67 static int rtpref __P((struct nd_defrouter *));
   68 static struct nd_defrouter *defrtrlist_update __P((struct nd_defrouter *));
   69 static int prelist_update __P((struct nd_prefixctl *, struct nd_defrouter *,
   70     struct mbuf *, int));
   71 static struct in6_ifaddr *in6_ifadd __P((struct nd_prefixctl *, int));
   72 static struct nd_pfxrouter *pfxrtr_lookup __P((struct nd_prefix *,
   73         struct nd_defrouter *));
   74 static void pfxrtr_add __P((struct nd_prefix *, struct nd_defrouter *));
   75 static void pfxrtr_del __P((struct nd_pfxrouter *));
   76 static struct nd_pfxrouter *find_pfxlist_reachable_router
   77         __P((struct nd_prefix *));
   78 static void defrouter_delreq __P((struct nd_defrouter *));
   79 static void nd6_rtmsg __P((int, struct rtentry *));
   80 
   81 static int in6_init_prefix_ltimes __P((struct nd_prefix *));
   82 static void in6_init_address_ltimes __P((struct nd_prefix *ndpr,
   83         struct in6_addrlifetime *lt6));
   84 
   85 static int rt6_deleteroute __P((struct radix_node *, void *));
   86 
   87 extern int nd6_recalc_reachtm_interval;
   88 
   89 static struct ifnet *nd6_defifp;
   90 int nd6_defifindex;
   91 
   92 int ip6_use_tempaddr = 0;
   93 
   94 int ip6_desync_factor;
   95 u_int32_t ip6_temp_preferred_lifetime = DEF_TEMP_PREFERRED_LIFETIME;
   96 u_int32_t ip6_temp_valid_lifetime = DEF_TEMP_VALID_LIFETIME;
   97 int ip6_temp_regen_advance = TEMPADDR_REGEN_ADVANCE;
   98 
   99 /* RTPREF_MEDIUM has to be 0! */
  100 #define RTPREF_HIGH     1
  101 #define RTPREF_MEDIUM   0
  102 #define RTPREF_LOW      (-1)
  103 #define RTPREF_RESERVED (-2)
  104 #define RTPREF_INVALID  (-3)    /* internal */
  105 
  106 /*
  107  * Receive Router Solicitation Message - just for routers.
  108  * Router solicitation/advertisement is mostly managed by userland program
  109  * (rtadvd) so here we have no function like nd6_ra_output().
  110  *
  111  * Based on RFC 2461
  112  */
  113 void
  114 nd6_rs_input(m, off, icmp6len)
  115         struct  mbuf *m;
  116         int off, icmp6len;
  117 {
  118         struct ifnet *ifp = m->m_pkthdr.rcvif;
  119         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  120         struct nd_router_solicit *nd_rs;
  121         struct in6_addr saddr6 = ip6->ip6_src;
  122 #if 0
  123         struct in6_addr daddr6 = ip6->ip6_dst;
  124 #endif
  125         char *lladdr = NULL;
  126         int lladdrlen = 0;
  127 #if 0
  128         struct sockaddr_dl *sdl = (struct sockaddr_dl *)NULL;
  129         struct llinfo_nd6 *ln = (struct llinfo_nd6 *)NULL;
  130         struct rtentry *rt = NULL;
  131         int is_newentry;
  132 #endif
  133         union nd_opts ndopts;
  134 
  135         /* If I'm not a router, ignore it. */
  136         if (ip6_accept_rtadv != 0 || !ip6_forwarding)
  137                 goto freeit;
  138 
  139         /* Sanity checks */
  140         if (ip6->ip6_hlim != 255) {
  141                 nd6log((LOG_ERR,
  142                     "nd6_rs_input: invalid hlim (%d) from %s to %s on %s\n",
  143                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  144                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  145                 goto bad;
  146         }
  147 
  148         /*
  149          * Don't update the neighbor cache, if src = ::.
  150          * This indicates that the src has no IP address assigned yet.
  151          */
  152         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  153                 goto freeit;
  154 
  155         IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
  156         if (nd_rs == NULL) {
  157                 icmp6stat.icp6s_tooshort++;
  158                 return;
  159         }
  160 
  161         icmp6len -= sizeof(*nd_rs);
  162         nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
  163         if (nd6_options(&ndopts) < 0) {
  164                 nd6log((LOG_INFO,
  165                     "nd6_rs_input: invalid ND option, ignored\n"));
  166                 /* nd6_options have incremented stats */
  167                 goto freeit;
  168         }
  169 
  170         if (ndopts.nd_opts_src_lladdr) {
  171                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  172                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  173         }
  174 
  175         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  176                 nd6log((LOG_INFO,
  177                     "nd6_rs_input: lladdrlen mismatch for %s "
  178                     "(if %d, RS packet %d)\n",
  179                     ip6_sprintf(&saddr6), ifp->if_addrlen, lladdrlen - 2));
  180                 goto bad;
  181         }
  182 
  183         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
  184 
  185  freeit:
  186         m_freem(m);
  187         return;
  188 
  189  bad:
  190         icmp6stat.icp6s_badrs++;
  191         m_freem(m);
  192 }
  193 
  194 /*
  195  * Receive Router Advertisement Message.
  196  *
  197  * Based on RFC 2461
  198  * TODO: on-link bit on prefix information
  199  * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
  200  */
  201 void
  202 nd6_ra_input(m, off, icmp6len)
  203         struct  mbuf *m;
  204         int off, icmp6len;
  205 {
  206         struct ifnet *ifp = m->m_pkthdr.rcvif;
  207         struct nd_ifinfo *ndi = ND_IFINFO(ifp);
  208         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  209         struct nd_router_advert *nd_ra;
  210         struct in6_addr saddr6 = ip6->ip6_src;
  211 #if 0
  212         struct in6_addr daddr6 = ip6->ip6_dst;
  213         int flags; /* = nd_ra->nd_ra_flags_reserved; */
  214         int is_managed = ((flags & ND_RA_FLAG_MANAGED) != 0);
  215         int is_other = ((flags & ND_RA_FLAG_OTHER) != 0);
  216 #endif
  217         int mcast = 0;
  218         union nd_opts ndopts;
  219         struct nd_defrouter *dr;
  220 
  221         /*
  222          * We only accept RAs only when
  223          * the system-wide variable allows the acceptance, and
  224          * per-interface variable allows RAs on the receiving interface.
  225          */
  226         if (ip6_accept_rtadv == 0)
  227                 goto freeit;
  228         if (!(ndi->flags & ND6_IFF_ACCEPT_RTADV))
  229                 goto freeit;
  230 
  231         if (ip6->ip6_hlim != 255) {
  232                 nd6log((LOG_ERR,
  233                     "nd6_ra_input: invalid hlim (%d) from %s to %s on %s\n",
  234                     ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
  235                     ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
  236                 goto bad;
  237         }
  238 
  239         if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
  240                 nd6log((LOG_ERR,
  241                     "nd6_ra_input: src %s is not link-local\n",
  242                     ip6_sprintf(&saddr6)));
  243                 goto bad;
  244         }
  245 
  246         IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
  247         if (nd_ra == NULL) {
  248                 icmp6stat.icp6s_tooshort++;
  249                 return;
  250         }
  251 
  252         icmp6len -= sizeof(*nd_ra);
  253         nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
  254         if (nd6_options(&ndopts) < 0) {
  255                 nd6log((LOG_INFO,
  256                     "nd6_ra_input: invalid ND option, ignored\n"));
  257                 /* nd6_options have incremented stats */
  258                 goto freeit;
  259         }
  260 
  261     {
  262         struct nd_defrouter drtr;
  263         u_int32_t advreachable = nd_ra->nd_ra_reachable;
  264 
  265         /* remember if this is a multicasted advertisement */
  266         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
  267                 mcast = 1;
  268 
  269         memset(&drtr, 0, sizeof(drtr));
  270         drtr.rtaddr = saddr6;
  271         drtr.flags  = nd_ra->nd_ra_flags_reserved;
  272         drtr.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
  273         drtr.expire = time_second + drtr.rtlifetime;
  274         drtr.ifp = ifp;
  275         /* unspecified or not? (RFC 2461 6.3.4) */
  276         if (advreachable) {
  277                 NTOHL(advreachable);
  278                 if (advreachable <= MAX_REACHABLE_TIME &&
  279                     ndi->basereachable != advreachable) {
  280                         ndi->basereachable = advreachable;
  281                         ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
  282                         ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
  283                 }
  284         }
  285         if (nd_ra->nd_ra_retransmit)
  286                 ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
  287         if (nd_ra->nd_ra_curhoplimit)
  288                 ndi->chlim = nd_ra->nd_ra_curhoplimit;
  289         dr = defrtrlist_update(&drtr);
  290     }
  291 
  292         /*
  293          * prefix
  294          */
  295         if (ndopts.nd_opts_pi) {
  296                 struct nd_opt_hdr *pt;
  297                 struct nd_opt_prefix_info *pi = NULL;
  298                 struct nd_prefixctl pr;
  299 
  300                 for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
  301                      pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
  302                      pt = (struct nd_opt_hdr *)((caddr_t)pt +
  303                                                 (pt->nd_opt_len << 3))) {
  304                         if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
  305                                 continue;
  306                         pi = (struct nd_opt_prefix_info *)pt;
  307 
  308                         if (pi->nd_opt_pi_len != 4) {
  309                                 nd6log((LOG_INFO,
  310                                     "nd6_ra_input: invalid option "
  311                                     "len %d for prefix information option, "
  312                                     "ignored\n", pi->nd_opt_pi_len));
  313                                 continue;
  314                         }
  315 
  316                         if (128 < pi->nd_opt_pi_prefix_len) {
  317                                 nd6log((LOG_INFO,
  318                                     "nd6_ra_input: invalid prefix "
  319                                     "len %d for prefix information option, "
  320                                     "ignored\n", pi->nd_opt_pi_prefix_len));
  321                                 continue;
  322                         }
  323 
  324                         if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
  325                          || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
  326                                 nd6log((LOG_INFO,
  327                                     "nd6_ra_input: invalid prefix "
  328                                     "%s, ignored\n",
  329                                     ip6_sprintf(&pi->nd_opt_pi_prefix)));
  330                                 continue;
  331                         }
  332 
  333                         bzero(&pr, sizeof(pr));
  334                         pr.ndpr_prefix.sin6_family = AF_INET6;
  335                         pr.ndpr_prefix.sin6_len = sizeof(pr.ndpr_prefix);
  336                         pr.ndpr_prefix.sin6_addr = pi->nd_opt_pi_prefix;
  337                         pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;
  338 
  339                         pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
  340                             ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
  341                         pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
  342                             ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
  343                         pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
  344                         pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
  345                         pr.ndpr_pltime = ntohl(pi->nd_opt_pi_preferred_time);
  346 
  347                         (void)prelist_update(&pr, dr, m, mcast);
  348                 }
  349         }
  350 
  351         /*
  352          * MTU
  353          */
  354         if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
  355                 u_long mtu;
  356                 u_long maxmtu;
  357 
  358                 mtu = ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
  359 
  360                 /* lower bound */
  361                 if (mtu < IPV6_MMTU) {
  362                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
  363                             "mtu=%lu sent from %s, ignoring\n",
  364                             mtu, ip6_sprintf(&ip6->ip6_src)));
  365                         goto skip;
  366                 }
  367 
  368                 /* upper bound */
  369                 maxmtu = (ndi->maxmtu && ndi->maxmtu < ifp->if_mtu)
  370                     ? ndi->maxmtu : ifp->if_mtu;
  371                 if (mtu <= maxmtu) {
  372                         int change = (ndi->linkmtu != mtu);
  373 
  374                         ndi->linkmtu = mtu;
  375                         if (change) /* in6_maxmtu may change */
  376                                 in6_setmaxmtu();
  377                 } else {
  378                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
  379                             "mtu=%lu sent from %s; "
  380                             "exceeds maxmtu %lu, ignoring\n",
  381                             mtu, ip6_sprintf(&ip6->ip6_src), maxmtu));
  382                 }
  383         }
  384 
  385  skip:
  386 
  387         /*
  388          * Source link layer address
  389          */
  390     {
  391         char *lladdr = NULL;
  392         int lladdrlen = 0;
  393 
  394         if (ndopts.nd_opts_src_lladdr) {
  395                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  396                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  397         }
  398 
  399         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  400                 nd6log((LOG_INFO,
  401                     "nd6_ra_input: lladdrlen mismatch for %s "
  402                     "(if %d, RA packet %d)\n", ip6_sprintf(&saddr6),
  403                     ifp->if_addrlen, lladdrlen - 2));
  404                 goto bad;
  405         }
  406 
  407         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_ADVERT, 0);
  408 
  409         /*
  410          * Installing a link-layer address might change the state of the
  411          * router's neighbor cache, which might also affect our on-link
  412          * detection of adveritsed prefixes.
  413          */
  414         pfxlist_onlink_check();
  415     }
  416 
  417  freeit:
  418         m_freem(m);
  419         return;
  420 
  421  bad:
  422         icmp6stat.icp6s_badra++;
  423         m_freem(m);
  424 }
  425 
  426 /*
  427  * default router list processing sub routines
  428  */
  429 
  430 /* tell the change to user processes watching the routing socket. */
  431 static void
  432 nd6_rtmsg(cmd, rt)
  433         int cmd;
  434         struct rtentry *rt;
  435 {
  436         struct rt_addrinfo info;
  437 
  438         bzero((caddr_t)&info, sizeof(info));
  439         info.rti_info[RTAX_DST] = rt_key(rt);
  440         info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
  441         info.rti_info[RTAX_NETMASK] = rt_mask(rt);
  442         if (rt->rt_ifp) {
  443                 info.rti_info[RTAX_IFP] =
  444                     TAILQ_FIRST(&rt->rt_ifp->if_addrlist)->ifa_addr;
  445                 info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
  446         }
  447 
  448         rt_missmsg(cmd, &info, rt->rt_flags, 0);
  449 }
  450 
  451 void
  452 defrouter_addreq(new)
  453         struct nd_defrouter *new;
  454 {
  455         struct sockaddr_in6 def, mask, gate;
  456         struct rtentry *newrt = NULL;
  457         int s;
  458         int error;
  459 
  460         memset(&def, 0, sizeof(def));
  461         memset(&mask, 0, sizeof(mask));
  462         memset(&gate, 0,sizeof(gate)); /* for safety */
  463 
  464         def.sin6_len = mask.sin6_len = gate.sin6_len =
  465             sizeof(struct sockaddr_in6);
  466         def.sin6_family = mask.sin6_family = gate.sin6_family = AF_INET6;
  467         gate.sin6_addr = new->rtaddr;
  468 #ifndef SCOPEDROUTING
  469         gate.sin6_scope_id = 0; /* XXX */
  470 #endif
  471 
  472         s = splsoftnet();
  473         error = rtrequest(RTM_ADD, (struct sockaddr *)&def,
  474             (struct sockaddr *)&gate, (struct sockaddr *)&mask,
  475             RTF_GATEWAY, &newrt);
  476         if (newrt) {
  477                 nd6_rtmsg(RTM_ADD, newrt); /* tell user process */
  478                 newrt->rt_refcnt--;
  479         }
  480         if (error == 0)
  481                 new->installed = 1;
  482         splx(s);
  483         return;
  484 }
  485 
  486 struct nd_defrouter *
  487 defrouter_lookup(addr, ifp)
  488         struct in6_addr *addr;
  489         struct ifnet *ifp;
  490 {
  491         struct nd_defrouter *dr;
  492 
  493         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  494              dr = TAILQ_NEXT(dr, dr_entry)) {
  495                 if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr)) {
  496                         return (dr);
  497                 }
  498         }
  499 
  500         return (NULL);          /* search failed */
  501 }
  502 
  503 void
  504 defrtrlist_del(dr)
  505         struct nd_defrouter *dr;
  506 {
  507         struct nd_defrouter *deldr = NULL;
  508         struct nd_prefix *pr;
  509 
  510         /*
  511          * Flush all the routing table entries that use the router
  512          * as a next hop.
  513          */
  514         if (!ip6_forwarding && ip6_accept_rtadv) /* XXX: better condition? */
  515                 rt6_flush(&dr->rtaddr, dr->ifp);
  516 
  517         if (dr->installed) {
  518                 deldr = dr;
  519                 defrouter_delreq(dr);
  520         }
  521         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  522 
  523         /*
  524          * Also delete all the pointers to the router in each prefix lists.
  525          */
  526         LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
  527                 struct nd_pfxrouter *pfxrtr;
  528                 if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
  529                         pfxrtr_del(pfxrtr);
  530         }
  531         pfxlist_onlink_check();
  532 
  533         /*
  534          * If the router is the primary one, choose a new one.
  535          * Note that defrouter_select() will remove the current gateway
  536          * from the routing table.
  537          */
  538         if (deldr)
  539                 defrouter_select();
  540 
  541         free(dr, M_IP6NDP);
  542 }
  543 
  544 /*
  545  * Remove the default route for a given router.
  546  * This is just a subroutine function for defrouter_select(), and should
  547  * not be called from anywhere else.
  548  */
  549 static void
  550 defrouter_delreq(dr)
  551         struct nd_defrouter *dr;
  552 {
  553         struct sockaddr_in6 def, mask, gw;
  554         struct rtentry *oldrt = NULL;
  555 
  556 #ifdef DIAGNOSTIC
  557         if (dr == NULL)
  558                 panic("dr == NULL in defrouter_delreq");
  559 #endif
  560 
  561         bzero(&def, sizeof(def));
  562         bzero(&mask, sizeof(mask));
  563         bzero(&gw, sizeof(gw)); /* for safety */
  564 
  565         def.sin6_len = mask.sin6_len = gw.sin6_len =
  566             sizeof(struct sockaddr_in6);
  567         def.sin6_family = mask.sin6_family = gw.sin6_family = AF_INET6;
  568         gw.sin6_addr = dr->rtaddr;
  569 #ifndef SCOPEDROUTING
  570         gw.sin6_scope_id = 0;   /* XXX */
  571 #endif
  572 
  573         rtrequest(RTM_DELETE, (struct sockaddr *)&def,
  574             (struct sockaddr *)&gw,
  575             (struct sockaddr *)&mask, RTF_GATEWAY, &oldrt);
  576         if (oldrt) {
  577                 nd6_rtmsg(RTM_DELETE, oldrt);
  578                 if (oldrt->rt_refcnt <= 0) {
  579                         /*
  580                          * XXX: borrowed from the RTM_DELETE case of
  581                          * rtrequest().
  582                          */
  583                         oldrt->rt_refcnt++;
  584                         rtfree(oldrt);
  585                 }
  586         }
  587 
  588         dr->installed = 0;
  589 }
  590 
  591 /*
  592  * remove all default routes from default router list
  593  */
  594 void
  595 defrouter_reset()
  596 {
  597         struct nd_defrouter *dr;
  598 
  599         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  600              dr = TAILQ_NEXT(dr, dr_entry))
  601                 defrouter_delreq(dr);
  602 
  603         /*
  604          * XXX should we also nuke any default routers in the kernel, by
  605          * going through them by rtalloc1()?
  606          */
  607 }
  608 
  609 /*
  610  * Default Router Selection according to Section 6.3.6 of RFC 2461 and
  611  * draft-ietf-ipngwg-router-selection:
  612  * 1) Routers that are reachable or probably reachable should be preferred.
  613  *    If we have more than one (probably) reachable router, prefer ones
  614  *    with the highest router preference.
  615  * 2) When no routers on the list are known to be reachable or
  616  *    probably reachable, routers SHOULD be selected in a round-robin
  617  *    fashion, regardless of router preference values.
  618  * 3) If the Default Router List is empty, assume that all
  619  *    destinations are on-link.
  620  *
  621  * We assume nd_defrouter is sorted by router preference value.
  622  * Since the code below covers both with and without router preference cases,
  623  * we do not need to classify the cases by ifdef.
  624  *
  625  * At this moment, we do not try to install more than one default router,
  626  * even when the multipath routing is available, because we're not sure about
  627  * the benefits for stub hosts comparing to the risk of making the code
  628  * complicated and the possibility of introducing bugs.
  629  */
  630 void
  631 defrouter_select()
  632 {
  633         int s = splsoftnet();
  634         struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
  635         struct rtentry *rt = NULL;
  636         struct llinfo_nd6 *ln = NULL;
  637 
  638         /*
  639          * This function should be called only when acting as an autoconfigured
  640          * host.  Although the remaining part of this function is not effective
  641          * if the node is not an autoconfigured host, we explicitly exclude
  642          * such cases here for safety.
  643          */
  644         if (ip6_forwarding || !ip6_accept_rtadv) {
  645                 nd6log((LOG_WARNING,
  646                     "defrouter_select: called unexpectedly (forwarding=%d, "
  647                     "accept_rtadv=%d)\n", ip6_forwarding, ip6_accept_rtadv));
  648                 splx(s);
  649                 return;
  650         }
  651 
  652         /*
  653          * Let's handle easy case (3) first:
  654          * If default router list is empty, there's nothing to be done.
  655          */
  656         if (!TAILQ_FIRST(&nd_defrouter)) {
  657                 splx(s);
  658                 return;
  659         }
  660 
  661         /*
  662          * Search for a (probably) reachable router from the list.
  663          * We just pick up the first reachable one (if any), assuming that
  664          * the ordering rule of the list described in defrtrlist_update().
  665          */
  666         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  667              dr = TAILQ_NEXT(dr, dr_entry)) {
  668                 if (selected_dr == NULL &&
  669                     (rt = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) != NULL &&
  670                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) != NULL &&
  671                     ND6_IS_LLINFO_PROBREACH(ln)) {
  672                         selected_dr = dr;
  673                 }
  674 
  675                 if (dr->installed && !installed_dr)
  676                         installed_dr = dr;
  677                 else if (dr->installed && installed_dr) {
  678                         /* this should not happen.  warn for diagnosis. */
  679                         log(LOG_ERR, "defrouter_select: more than one router"
  680                             " is installed\n");
  681                 }
  682         }
  683         /*
  684          * If none of the default routers was found to be reachable,
  685          * round-robin the list regardless of preference.
  686          * Otherwise, if we have an installed router, check if the selected
  687          * (reachable) router should really be preferred to the installed one.
  688          * We only prefer the new router when the old one is not reachable
  689          * or when the new one has a really higher preference value.
  690          */
  691         if (selected_dr == NULL) {
  692                 if (installed_dr == NULL || !TAILQ_NEXT(installed_dr, dr_entry))
  693                         selected_dr = TAILQ_FIRST(&nd_defrouter);
  694                 else
  695                         selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
  696         } else if (installed_dr &&
  697             (rt = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp)) &&
  698             (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
  699             ND6_IS_LLINFO_PROBREACH(ln) &&
  700             rtpref(selected_dr) <= rtpref(installed_dr)) {
  701                 selected_dr = installed_dr;
  702         }
  703 
  704         /*
  705          * If the selected router is different than the installed one,
  706          * remove the installed router and install the selected one.
  707          * Note that the selected router is never NULL here.
  708          */
  709         if (installed_dr != selected_dr) {
  710                 if (installed_dr)
  711                         defrouter_delreq(installed_dr);
  712                 defrouter_addreq(selected_dr);
  713         }
  714 
  715         splx(s);
  716         return;
  717 }
  718 
  719 /*
  720  * for default router selection
  721  * regards router-preference field as a 2-bit signed integer
  722  */
  723 static int
  724 rtpref(struct nd_defrouter *dr)
  725 {
  726         switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
  727         case ND_RA_FLAG_RTPREF_HIGH:
  728                 return (RTPREF_HIGH);
  729         case ND_RA_FLAG_RTPREF_MEDIUM:
  730         case ND_RA_FLAG_RTPREF_RSV:
  731                 return (RTPREF_MEDIUM);
  732         case ND_RA_FLAG_RTPREF_LOW:
  733                 return (RTPREF_LOW);
  734         default:
  735                 /*
  736                  * This case should never happen.  If it did, it would mean a
  737                  * serious bug of kernel internal.  We thus always bark here.
  738                  * Or, can we even panic?
  739                  */
  740                 log(LOG_ERR, "rtpref: impossible RA flag %x\n", dr->flags);
  741                 return (RTPREF_INVALID);
  742         }
  743         /* NOTREACHED */
  744 }
  745 
  746 static struct nd_defrouter *
  747 defrtrlist_update(new)
  748         struct nd_defrouter *new;
  749 {
  750         struct nd_defrouter *dr, *n;
  751         int s = splsoftnet();
  752 
  753         if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
  754                 /* entry exists */
  755                 if (new->rtlifetime == 0) {
  756                         defrtrlist_del(dr);
  757                         dr = NULL;
  758                 } else {
  759                         int oldpref = rtpref(dr);
  760 
  761                         /* override */
  762                         dr->flags = new->flags; /* xxx flag check */
  763                         dr->rtlifetime = new->rtlifetime;
  764                         dr->expire = new->expire;
  765 
  766                         /*
  767                          * If the preference does not change, there's no need
  768                          * to sort the entries.
  769                          */
  770                         if (rtpref(new) == oldpref) {
  771                                 splx(s);
  772                                 return (dr);
  773                         }
  774 
  775                         /*
  776                          * preferred router may be changed, so relocate
  777                          * this router.
  778                          * XXX: calling TAILQ_REMOVE directly is a bad manner.
  779                          * However, since defrtrlist_del() has many side
  780                          * effects, we intentionally do so here.
  781                          * defrouter_select() below will handle routing
  782                          * changes later.
  783                          */
  784                         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  785                         n = dr;
  786                         goto insert;
  787                 }
  788                 splx(s);
  789                 return (dr);
  790         }
  791 
  792         /* entry does not exist */
  793         if (new->rtlifetime == 0) {
  794                 splx(s);
  795                 return (NULL);
  796         }
  797 
  798         n = (struct nd_defrouter *)malloc(sizeof(*n), M_IP6NDP, M_NOWAIT);
  799         if (n == NULL) {
  800                 splx(s);
  801                 return (NULL);
  802         }
  803         bzero(n, sizeof(*n));
  804         *n = *new;
  805 
  806 insert:
  807         /*
  808          * Insert the new router in the Default Router List;
  809          * The Default Router List should be in the descending order
  810          * of router-preferece.  Routers with the same preference are
  811          * sorted in the arriving time order.
  812          */
  813 
  814         /* insert at the end of the group */
  815         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  816              dr = TAILQ_NEXT(dr, dr_entry)) {
  817                 if (rtpref(n) > rtpref(dr))
  818                         break;
  819         }
  820         if (dr)
  821                 TAILQ_INSERT_BEFORE(dr, n, dr_entry);
  822         else
  823                 TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);
  824 
  825         defrouter_select();
  826 
  827         splx(s);
  828 
  829         return (n);
  830 }
  831 
  832 static struct nd_pfxrouter *
  833 pfxrtr_lookup(pr, dr)
  834         struct nd_prefix *pr;
  835         struct nd_defrouter *dr;
  836 {
  837         struct nd_pfxrouter *search;
  838 
  839         LIST_FOREACH(search, &pr->ndpr_advrtrs, pfr_entry) {
  840                 if (search->router == dr)
  841                         break;
  842         }
  843 
  844         return (search);
  845 }
  846 
  847 static void
  848 pfxrtr_add(pr, dr)
  849         struct nd_prefix *pr;
  850         struct nd_defrouter *dr;
  851 {
  852         struct nd_pfxrouter *new;
  853 
  854         new = (struct nd_pfxrouter *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  855         if (new == NULL)
  856                 return;
  857         bzero(new, sizeof(*new));
  858         new->router = dr;
  859 
  860         LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
  861 
  862         pfxlist_onlink_check();
  863 }
  864 
  865 static void
  866 pfxrtr_del(pfr)
  867         struct nd_pfxrouter *pfr;
  868 {
  869         LIST_REMOVE(pfr, pfr_entry);
  870         free(pfr, M_IP6NDP);
  871 }
  872 
  873 struct nd_prefix *
  874 nd6_prefix_lookup(key)
  875         struct nd_prefixctl *key;
  876 {
  877         struct nd_prefix *search;
  878 
  879         LIST_FOREACH(search, &nd_prefix, ndpr_entry) {
  880                 if (key->ndpr_ifp == search->ndpr_ifp &&
  881                     key->ndpr_plen == search->ndpr_plen &&
  882                     in6_are_prefix_equal(&key->ndpr_prefix.sin6_addr,
  883                     &search->ndpr_prefix.sin6_addr, key->ndpr_plen)) {
  884                         break;
  885                 }
  886         }
  887 
  888         return (search);
  889 }
  890 
  891 int
  892 nd6_prelist_add(pr, dr, newp)
  893         struct nd_prefixctl *pr;
  894         struct nd_prefix **newp;
  895         struct nd_defrouter *dr;
  896 {
  897         struct nd_prefix *new = NULL;
  898         int i, s;
  899         int error;
  900 
  901         error = 0;
  902         new = (struct nd_prefix *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  903         if (new == NULL)
  904                 return ENOMEM;
  905         bzero(new, sizeof(*new));
  906         new->ndpr_ifp = pr->ndpr_ifp;
  907         new->ndpr_prefix = pr->ndpr_prefix;
  908         new->ndpr_plen = pr->ndpr_plen;
  909         new->ndpr_vltime = pr->ndpr_vltime;
  910         new->ndpr_pltime = pr->ndpr_pltime;
  911         new->ndpr_flags = pr->ndpr_flags;
  912         if ((error = in6_init_prefix_ltimes(new)) != 0) {
  913                 free(new, M_IP6NDP);
  914                 return(error);
  915         }
  916         new->ndpr_lastupdate = time_second;
  917         if (newp != NULL)
  918                 *newp = new;
  919 
  920         /* initialization */
  921         LIST_INIT(&new->ndpr_advrtrs);
  922         in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
  923         /* make prefix in the canonical form */
  924         for (i = 0; i < 4; i++)
  925                 new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
  926                     new->ndpr_mask.s6_addr32[i];
  927 
  928         s = splsoftnet();
  929         /* link ndpr_entry to nd_prefix list */
  930         LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
  931         splx(s);
  932 
  933         /* ND_OPT_PI_FLAG_ONLINK processing */
  934         if (new->ndpr_raf_onlink) {
  935                 int e;
  936 
  937                 if ((e = nd6_prefix_onlink(new)) != 0) {
  938                         nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
  939                             "the prefix %s/%d on-link on %s (errno=%d)\n",
  940                             ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
  941                             pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  942                         /* proceed anyway. XXX: is it correct? */
  943                 }
  944         }
  945 
  946         if (dr)
  947                 pfxrtr_add(new, dr);
  948 
  949         return 0;
  950 }
  951 
  952 void
  953 prelist_remove(pr)
  954         struct nd_prefix *pr;
  955 {
  956         struct nd_pfxrouter *pfr, *next;
  957         int e, s;
  958 
  959         /* make sure to invalidate the prefix until it is really freed. */
  960         pr->ndpr_vltime = 0;
  961         pr->ndpr_pltime = 0;
  962 #if 0
  963         /*
  964          * Though these flags are now meaningless, we'd rather keep the value
  965          * not to confuse users when executing "ndp -p".
  966          */
  967         pr->ndpr_raf_onlink = 0;
  968         pr->ndpr_raf_auto = 0;
  969 #endif
  970         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
  971             (e = nd6_prefix_offlink(pr)) != 0) {
  972                 nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
  973                     "on %s, errno=%d\n",
  974                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
  975                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  976                 /* what should we do? */
  977         }
  978 
  979         if (pr->ndpr_refcnt > 0)
  980                 return;         /* notice here? */
  981 
  982         s = splsoftnet();
  983         /* unlink ndpr_entry from nd_prefix list */
  984         LIST_REMOVE(pr, ndpr_entry);
  985 
  986         /* free list of routers that adversed the prefix */
  987         for (pfr = LIST_FIRST(&pr->ndpr_advrtrs); pfr != NULL; pfr = next) {
  988                 next = LIST_NEXT(pfr, pfr_entry);
  989 
  990                 free(pfr, M_IP6NDP);
  991         }
  992         splx(s);
  993 
  994         free(pr, M_IP6NDP);
  995 
  996         pfxlist_onlink_check();
  997 }
  998 
  999 static int
 1000 prelist_update(new, dr, m, mcast)
 1001         struct nd_prefixctl *new;
 1002         struct nd_defrouter *dr; /* may be NULL */
 1003         struct mbuf *m;
 1004         int mcast;
 1005 {
 1006         struct in6_ifaddr *ia6 = NULL, *ia6_match = NULL;
 1007         struct ifaddr *ifa;
 1008         struct ifnet *ifp = new->ndpr_ifp;
 1009         struct nd_prefix *pr;
 1010         int s = splsoftnet();
 1011         int error = 0;
 1012         int newprefix = 0;
 1013         int auth;
 1014         struct in6_addrlifetime lt6_tmp;
 1015 
 1016         auth = 0;
 1017         if (m) {
 1018                 /*
 1019                  * Authenticity for NA consists authentication for
 1020                  * both IP header and IP datagrams, doesn't it ?
 1021                  */
 1022 #if defined(M_AUTHIPHDR) && defined(M_AUTHIPDGM)
 1023                 auth = (m->m_flags & M_AUTHIPHDR
 1024                      && m->m_flags & M_AUTHIPDGM) ? 1 : 0;
 1025 #endif
 1026         }
 1027 
 1028         if ((pr = nd6_prefix_lookup(new)) != NULL) {
 1029                 /*
 1030                  * nd6_prefix_lookup() ensures that pr and new have the same
 1031                  * prefix on a same interface.
 1032                  */
 1033 
 1034                 /*
 1035                  * Update prefix information.  Note that the on-link (L) bit
 1036                  * and the autonomous (A) bit should NOT be changed from 1
 1037                  * to 0.
 1038                  */
 1039                 if (new->ndpr_raf_onlink == 1)
 1040                         pr->ndpr_raf_onlink = 1;
 1041                 if (new->ndpr_raf_auto == 1)
 1042                         pr->ndpr_raf_auto = 1;
 1043                 if (new->ndpr_raf_onlink) {
 1044                         pr->ndpr_vltime = new->ndpr_vltime;
 1045                         pr->ndpr_pltime = new->ndpr_pltime;
 1046                         (void)in6_init_prefix_ltimes(pr); /* XXX error case? */
 1047                         pr->ndpr_lastupdate = time_second;
 1048                 }
 1049 
 1050                 if (new->ndpr_raf_onlink &&
 1051                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1052                         int e;
 1053 
 1054                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1055                                 nd6log((LOG_ERR,
 1056                                     "prelist_update: failed to make "
 1057                                     "the prefix %s/%d on-link on %s "
 1058                                     "(errno=%d)\n",
 1059                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1060                                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
 1061                                 /* proceed anyway. XXX: is it correct? */
 1062                         }
 1063                 }
 1064 
 1065                 if (dr && pfxrtr_lookup(pr, dr) == NULL)
 1066                         pfxrtr_add(pr, dr);
 1067         } else {
 1068                 struct nd_prefix *newpr = NULL;
 1069 
 1070                 newprefix = 1;
 1071 
 1072                 if (new->ndpr_vltime == 0)
 1073                         goto end;
 1074                 if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
 1075                         goto end;
 1076 
 1077                 error = nd6_prelist_add(new, dr, &newpr);
 1078                 if (error != 0 || newpr == NULL) {
 1079                         nd6log((LOG_NOTICE, "prelist_update: "
 1080                             "nd6_prelist_add failed for %s/%d on %s "
 1081                             "errno=%d, returnpr=%p\n",
 1082                             ip6_sprintf(&new->ndpr_prefix.sin6_addr),
 1083                             new->ndpr_plen, if_name(new->ndpr_ifp),
 1084                             error, newpr));
 1085                         goto end; /* we should just give up in this case. */
 1086                 }
 1087 
 1088                 /*
 1089                  * XXX: from the ND point of view, we can ignore a prefix
 1090                  * with the on-link bit being zero.  However, we need a
 1091                  * prefix structure for references from autoconfigured
 1092                  * addresses.  Thus, we explicitly make sure that the prefix
 1093                  * itself expires now.
 1094                  */
 1095                 if (newpr->ndpr_raf_onlink == 0) {
 1096                         newpr->ndpr_vltime = 0;
 1097                         newpr->ndpr_pltime = 0;
 1098                         in6_init_prefix_ltimes(newpr);
 1099                 }
 1100 
 1101                 pr = newpr;
 1102         }
 1103 
 1104         /*
 1105          * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
 1106          * Note that pr must be non NULL at this point.
 1107          */
 1108 
 1109         /* 5.5.3 (a). Ignore the prefix without the A bit set. */
 1110         if (!new->ndpr_raf_auto)
 1111                 goto end;
 1112 
 1113         /*
 1114          * 5.5.3 (b). the link-local prefix should have been ignored in
 1115          * nd6_ra_input.
 1116          */
 1117 
 1118         /* 5.5.3 (c). Consistency check on lifetimes: pltime <= vltime. */
 1119         if (new->ndpr_pltime > new->ndpr_vltime) {
 1120                 error = EINVAL; /* XXX: won't be used */
 1121                 goto end;
 1122         }
 1123 
 1124         /*
 1125          * 5.5.3 (d).  If the prefix advertised is not equal to the prefix of
 1126          * an address configured by stateless autoconfiguration already in the
 1127          * list of addresses associated with the interface, and the Valid
 1128          * Lifetime is not 0, form an address.  We first check if we have
 1129          * a matching prefix.
 1130          * Note: we apply a clarification in rfc2462bis-02 here.  We only
 1131          * consider autoconfigured addresses while RFC2462 simply said
 1132          * "address".
 1133          */
 1134         TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
 1135                 struct in6_ifaddr *ifa6;
 1136                 u_int32_t remaininglifetime;
 1137 
 1138                 if (ifa->ifa_addr->sa_family != AF_INET6)
 1139                         continue;
 1140 
 1141                 ifa6 = (struct in6_ifaddr *)ifa;
 1142 
 1143                 /*
 1144                  * We only consider autoconfigured addresses as per rfc2462bis.
 1145                  */
 1146                 if (!(ifa6->ia6_flags & IN6_IFF_AUTOCONF))
 1147                         continue;
 1148 
 1149                 /*
 1150                  * Spec is not clear here, but I believe we should concentrate
 1151                  * on unicast (i.e. not anycast) addresses.
 1152                  * XXX: other ia6_flags? detached or duplicated?
 1153                  */
 1154                 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0)
 1155                         continue;
 1156 
 1157                 /*
 1158                  * Ignore the address if it is not associated with a prefix
 1159                  * or is associated with a prefix that is different from this
 1160                  * one.  (pr is never NULL here)
 1161                  */
 1162                 if (ifa6->ia6_ndpr != pr)
 1163                         continue;
 1164 
 1165                 if (ia6_match == NULL) /* remember the first one */
 1166                         ia6_match = ifa6;
 1167 
 1168                 /*
 1169                  * An already autoconfigured address matched.  Now that we
 1170                  * are sure there is at least one matched address, we can
 1171                  * proceed to 5.5.3. (e): update the lifetimes according to the
 1172                  * "two hours" rule and the privacy extension.
 1173                  * We apply some clarifications in rfc2462bis:
 1174                  * - use remaininglifetime instead of storedlifetime as a
 1175                  *   variable name
 1176                  * - remove the dead code in the "two-hour" rule
 1177                  */
 1178 #define TWOHOUR         (120*60)
 1179                 lt6_tmp = ifa6->ia6_lifetime;
 1180                 if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME)
 1181                         remaininglifetime = ND6_INFINITE_LIFETIME;
 1182                 else if (time_second - ifa6->ia6_updatetime >
 1183                          lt6_tmp.ia6t_vltime) {
 1184                         /*
 1185                          * The case of "invalid" address.  We should usually
 1186                          * not see this case.
 1187                          */
 1188                         remaininglifetime = 0;
 1189                 } else
 1190                         remaininglifetime = lt6_tmp.ia6t_vltime -
 1191                             (time_second - ifa6->ia6_updatetime);
 1192 
 1193                 /* when not updating, keep the current stored lifetime. */
 1194                 lt6_tmp.ia6t_vltime = remaininglifetime;
 1195 
 1196                 if (TWOHOUR < new->ndpr_vltime ||
 1197                     remaininglifetime < new->ndpr_vltime) {
 1198                         lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1199                 } else if (remaininglifetime <= TWOHOUR) {
 1200                         if (auth)
 1201                                 lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1202                 } else {
 1203                         /*
 1204                          * new->ndpr_vltime <= TWOHOUR &&
 1205                          * TWOHOUR < remaininglifetime
 1206                          */
 1207                         lt6_tmp.ia6t_vltime = TWOHOUR;
 1208                 }
 1209 
 1210                 /* The 2 hour rule is not imposed for preferred lifetime. */
 1211                 lt6_tmp.ia6t_pltime = new->ndpr_pltime;
 1212 
 1213                 in6_init_address_ltimes(pr, &lt6_tmp);
 1214 
 1215                 /*
 1216                  * We need to treat lifetimes for temporary addresses
 1217                  * differently, according to
 1218                  * draft-ietf-ipv6-privacy-addrs-v2-01.txt 3.3 (1);
 1219                  * we only update the lifetimes when they are in the maximum
 1220                  * intervals.
 1221                  */
 1222                 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0) {
 1223                         u_int32_t maxvltime, maxpltime;
 1224 
 1225                         if (ip6_temp_valid_lifetime >
 1226                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1227                             ip6_desync_factor)) {
 1228                                 maxvltime = ip6_temp_valid_lifetime -
 1229                                     (time_second - ifa6->ia6_createtime) -
 1230                                     ip6_desync_factor;
 1231                         } else
 1232                                 maxvltime = 0;
 1233                         if (ip6_temp_preferred_lifetime >
 1234                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1235                             ip6_desync_factor)) {
 1236                                 maxpltime = ip6_temp_preferred_lifetime -
 1237                                     (time_second - ifa6->ia6_createtime) -
 1238                                     ip6_desync_factor;
 1239                         } else
 1240                                 maxpltime = 0;
 1241 
 1242                         if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME ||
 1243                             lt6_tmp.ia6t_vltime > maxvltime) {
 1244                                 lt6_tmp.ia6t_vltime = maxvltime;
 1245                         }
 1246                         if (lt6_tmp.ia6t_pltime == ND6_INFINITE_LIFETIME ||
 1247                             lt6_tmp.ia6t_pltime > maxpltime) {
 1248                                 lt6_tmp.ia6t_pltime = maxpltime;
 1249                         }
 1250                 }
 1251 
 1252                 ifa6->ia6_lifetime = lt6_tmp;
 1253                 ifa6->ia6_updatetime = time_second;
 1254         }
 1255         if (ia6_match == NULL && new->ndpr_vltime) {
 1256                 int ifidlen;
 1257 
 1258                 /*
 1259                  * 5.5.3 (d) (continued)
 1260                  * No address matched and the valid lifetime is non-zero.
 1261                  * Create a new address.
 1262                  */
 1263 
 1264                 /*
 1265                  * Prefix Length check:
 1266                  * If the sum of the prefix length and interface identifier
 1267                  * length does not equal 128 bits, the Prefix Information
 1268                  * option MUST be ignored.  The length of the interface
 1269                  * identifier is defined in a separate link-type specific
 1270                  * document.
 1271                  */
 1272                 ifidlen = in6_if2idlen(ifp);
 1273                 if (ifidlen < 0) {
 1274                         /* this should not happen, so we always log it. */
 1275                         log(LOG_ERR, "prelist_update: IFID undefined (%s)\n",
 1276                             if_name(ifp));
 1277                         goto end;
 1278                 }
 1279                 if (ifidlen + pr->ndpr_plen != 128) {
 1280                         nd6log((LOG_INFO,
 1281                             "prelist_update: invalid prefixlen "
 1282                             "%d for %s, ignored\n",
 1283                             pr->ndpr_plen, if_name(ifp)));
 1284                         goto end;
 1285                 }
 1286 
 1287                 if ((ia6 = in6_ifadd(new, mcast)) != NULL) {
 1288                         /*
 1289                          * note that we should use pr (not new) for reference.
 1290                          */
 1291                         pr->ndpr_refcnt++;
 1292                         ia6->ia6_ndpr = pr;
 1293 
 1294                         /*
 1295                          * draft-ietf-ipngwg-temp-addresses-v2-00 3.3 (2).
 1296                          * When a new public address is created as described
 1297                          * in RFC2462, also create a new temporary address.
 1298                          *
 1299                          * draft-ietf-ipngwg-temp-addresses-v2-00 3.5.
 1300                          * When an interface connects to a new link, a new
 1301                          * randomized interface identifier should be generated
 1302                          * immediately together with a new set of temporary
 1303                          * addresses.  Thus, we specifiy 1 as the 2nd arg of
 1304                          * in6_tmpifadd().
 1305                          */
 1306                         if (ip6_use_tempaddr) {
 1307                                 int e;
 1308                                 if ((e = in6_tmpifadd(ia6, 1, 1)) != 0) {
 1309                                         nd6log((LOG_NOTICE, "prelist_update: "
 1310                                             "failed to create a temporary "
 1311                                             "address, errno=%d\n",
 1312                                             e));
 1313                                 }
 1314                         }
 1315 
 1316                         /*
 1317                          * A newly added address might affect the status
 1318                          * of other addresses, so we check and update it.
 1319                          * XXX: what if address duplication happens?
 1320                          */
 1321                         pfxlist_onlink_check();
 1322                 } else {
 1323                         /* just set an error. do not bark here. */
 1324                         error = EADDRNOTAVAIL; /* XXX: might be unused. */
 1325                 }
 1326         }
 1327 
 1328  end:
 1329         splx(s);
 1330         return error;
 1331 }
 1332 
 1333 /*
 1334  * A supplement function used in the on-link detection below;
 1335  * detect if a given prefix has a (probably) reachable advertising router.
 1336  * XXX: lengthy function name...
 1337  */
 1338 static struct nd_pfxrouter *
 1339 find_pfxlist_reachable_router(pr)
 1340         struct nd_prefix *pr;
 1341 {
 1342         struct nd_pfxrouter *pfxrtr;
 1343         struct rtentry *rt;
 1344         struct llinfo_nd6 *ln;
 1345 
 1346         for (pfxrtr = LIST_FIRST(&pr->ndpr_advrtrs); pfxrtr;
 1347              pfxrtr = LIST_NEXT(pfxrtr, pfr_entry)) {
 1348                 if ((rt = nd6_lookup(&pfxrtr->router->rtaddr, 0,
 1349                     pfxrtr->router->ifp)) &&
 1350                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
 1351                     ND6_IS_LLINFO_PROBREACH(ln))
 1352                         break;  /* found */
 1353         }
 1354 
 1355         return (pfxrtr);
 1356 }
 1357 
 1358 /*
 1359  * Check if each prefix in the prefix list has at least one available router
 1360  * that advertised the prefix (a router is "available" if its neighbor cache
 1361  * entry is reachable or probably reachable).
 1362  * If the check fails, the prefix may be off-link, because, for example,
 1363  * we have moved from the network but the lifetime of the prefix has not
 1364  * expired yet.  So we should not use the prefix if there is another prefix
 1365  * that has an available router.
 1366  * But, if there is no prefix that has an available router, we still regards
 1367  * all the prefixes as on-link.  This is because we can't tell if all the
 1368  * routers are simply dead or if we really moved from the network and there
 1369  * is no router around us.
 1370  */
 1371 void
 1372 pfxlist_onlink_check()
 1373 {
 1374         struct nd_prefix *pr;
 1375         struct in6_ifaddr *ifa;
 1376         struct nd_defrouter *dr;
 1377         struct nd_pfxrouter *pfxrtr = NULL;
 1378 
 1379         /*
 1380          * Check if there is a prefix that has a reachable advertising
 1381          * router.
 1382          */
 1383         LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1384                 if (pr->ndpr_raf_onlink && find_pfxlist_reachable_router(pr))
 1385                         break;
 1386         }
 1387         /*
 1388          * If we have no such prefix, check whether we still have a router
 1389          * that does not advertise any prefixes.
 1390          */
 1391         if (pr == NULL) {
 1392                 TAILQ_FOREACH(dr, &nd_defrouter, dr_entry) {
 1393                         struct nd_prefix *pr0;
 1394 
 1395                         LIST_FOREACH(pr0, &nd_prefix, ndpr_entry) {
 1396                                 if ((pfxrtr = pfxrtr_lookup(pr0, dr)) != NULL)
 1397                                         break;
 1398                         }
 1399                         if (pfxrtr)
 1400                                 break;
 1401                 }
 1402         }
 1403         if (pr != NULL || (TAILQ_FIRST(&nd_defrouter) && !pfxrtr)) {
 1404                 /*
 1405                  * There is at least one prefix that has a reachable router,
 1406                  * or at least a router which probably does not advertise
 1407                  * any prefixes.  The latter would be the case when we move
 1408                  * to a new link where we have a router that does not provide
 1409                  * prefixes and we configure an address by hand.
 1410                  * Detach prefixes which have no reachable advertising
 1411                  * router, and attach other prefixes.
 1412                  */
 1413                 LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1414                         /* XXX: a link-local prefix should never be detached */
 1415                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1416                                 continue;
 1417 
 1418                         /*
 1419                          * we aren't interested in prefixes without the L bit
 1420                          * set.
 1421                          */
 1422                         if (pr->ndpr_raf_onlink == 0)
 1423                                 continue;
 1424 
 1425                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1426                             find_pfxlist_reachable_router(pr) == NULL)
 1427                                 pr->ndpr_stateflags |= NDPRF_DETACHED;
 1428                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1429                             find_pfxlist_reachable_router(pr) != 0)
 1430                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1431                 }
 1432         } else {
 1433                 /* there is no prefix that has a reachable router */
 1434                 LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1435                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1436                                 continue;
 1437 
 1438                         if (pr->ndpr_raf_onlink == 0)
 1439                                 continue;
 1440 
 1441                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1442                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1443                 }
 1444         }
 1445 
 1446         /*
 1447          * Remove each interface route associated with a (just) detached
 1448          * prefix, and reinstall the interface route for a (just) attached
 1449          * prefix.  Note that all attempt of reinstallation does not
 1450          * necessarily success, when a same prefix is shared among multiple
 1451          * interfaces.  Such cases will be handled in nd6_prefix_onlink,
 1452          * so we don't have to care about them.
 1453          */
 1454         LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
 1455                 int e;
 1456 
 1457                 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1458                         continue;
 1459 
 1460                 if (pr->ndpr_raf_onlink == 0)
 1461                         continue;
 1462 
 1463                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1464                     (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1465                         if ((e = nd6_prefix_offlink(pr)) != 0) {
 1466                                 nd6log((LOG_ERR,
 1467                                     "pfxlist_onlink_check: failed to "
 1468                                     "make %s/%d offlink, errno=%d\n",
 1469                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1470                                     pr->ndpr_plen, e));
 1471                         }
 1472                 }
 1473                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1474                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0 &&
 1475                     pr->ndpr_raf_onlink) {
 1476                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1477                                 nd6log((LOG_ERR,
 1478                                     "pfxlist_onlink_check: failed to "
 1479                                     "make %s/%d onlink, errno=%d\n",
 1480                                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1481                                     pr->ndpr_plen, e));
 1482                         }
 1483                 }
 1484         }
 1485 
 1486         /*
 1487          * Changes on the prefix status might affect address status as well.
 1488          * Make sure that all addresses derived from an attached prefix are
 1489          * attached, and that all addresses derived from a detached prefix are
 1490          * detached.  Note, however, that a manually configured address should
 1491          * always be attached.
 1492          * The precise detection logic is same as the one for prefixes.
 1493          */
 1494         for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1495                 if (!(ifa->ia6_flags & IN6_IFF_AUTOCONF))
 1496                         continue;
 1497 
 1498                 if (ifa->ia6_ndpr == NULL) {
 1499                         /*
 1500                          * This can happen when we first configure the address
 1501                          * (i.e. the address exists, but the prefix does not).
 1502                          * XXX: complicated relationships...
 1503                          */
 1504                         continue;
 1505                 }
 1506 
 1507                 if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
 1508                         break;
 1509         }
 1510         if (ifa) {
 1511                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1512                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1513                                 continue;
 1514 
 1515                         if (ifa->ia6_ndpr == NULL) /* XXX: see above. */
 1516                                 continue;
 1517 
 1518                         if (find_pfxlist_reachable_router(ifa->ia6_ndpr)) {
 1519                                 if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1520                                         ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1521                                         ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1522                                         nd6_dad_start((struct ifaddr *)ifa,
 1523                                             0);
 1524                                 }
 1525                         } else {
 1526                                 if ((ifa->ia6_flags & IN6_IFF_DETACHED) == 0) {
 1527                                         ifa->ia6_flags |= IN6_IFF_DETACHED;
 1528                                 }
 1529                         }
 1530                 }
 1531         }
 1532         else {
 1533                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1534                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1535                                 continue;
 1536 
 1537                         if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1538                                 ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1539                                 ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1540                                 /* Do we need a delay in this case? */
 1541                                 nd6_dad_start((struct ifaddr *)ifa, 0);
 1542                         }
 1543                 }
 1544         }
 1545 }
 1546 
 1547 int
 1548 nd6_prefix_onlink(pr)
 1549         struct nd_prefix *pr;
 1550 {
 1551         struct ifaddr *ifa;
 1552         struct ifnet *ifp = pr->ndpr_ifp;
 1553         struct sockaddr_in6 mask6;
 1554         struct nd_prefix *opr;
 1555         u_long rtflags;
 1556         int error = 0;
 1557         struct rtentry *rt = NULL;
 1558 
 1559         /* sanity check */
 1560         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1561                 nd6log((LOG_ERR,
 1562                     "nd6_prefix_onlink: %s/%d is already on-link\n",
 1563                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen));
 1564                 return (EEXIST);
 1565         }
 1566 
 1567         /*
 1568          * Add the interface route associated with the prefix.  Before
 1569          * installing the route, check if there's the same prefix on another
 1570          * interface, and the prefix has already installed the interface route.
 1571          * Although such a configuration is expected to be rare, we explicitly
 1572          * allow it.
 1573          */
 1574         LIST_FOREACH(opr, &nd_prefix, ndpr_entry) {
 1575                 if (opr == pr)
 1576                         continue;
 1577 
 1578                 if ((opr->ndpr_stateflags & NDPRF_ONLINK) == 0)
 1579                         continue;
 1580 
 1581                 if (opr->ndpr_plen == pr->ndpr_plen &&
 1582                     in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1583                     &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen))
 1584                         return (0);
 1585         }
 1586 
 1587         /*
 1588          * We prefer link-local addresses as the associated interface address.
 1589          */
 1590         /* search for a link-local addr */
 1591         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
 1592             IN6_IFF_NOTREADY | IN6_IFF_ANYCAST);
 1593         if (ifa == NULL) {
 1594                 /* XXX: freebsd does not have ifa_ifwithaf */
 1595                 TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
 1596                         if (ifa->ifa_addr->sa_family == AF_INET6)
 1597                                 break;
 1598                 }
 1599                 /* should we care about ia6_flags? */
 1600         }
 1601         if (ifa == NULL) {
 1602                 /*
 1603                  * This can still happen, when, for example, we receive an RA
 1604                  * containing a prefix with the L bit set and the A bit clear,
 1605                  * after removing all IPv6 addresses on the receiving
 1606                  * interface.  This should, of course, be rare though.
 1607                  */
 1608                 nd6log((LOG_NOTICE,
 1609                     "nd6_prefix_onlink: failed to find any ifaddr"
 1610                     " to add route for a prefix(%s/%d) on %s\n",
 1611                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1612                     pr->ndpr_plen, if_name(ifp)));
 1613                 return (0);
 1614         }
 1615 
 1616         /*
 1617          * in6_ifinit() sets nd6_rtrequest to ifa_rtrequest for all ifaddrs.
 1618          * ifa->ifa_rtrequest = nd6_rtrequest;
 1619          */
 1620         bzero(&mask6, sizeof(mask6));
 1621         mask6.sin6_len = sizeof(mask6);
 1622         mask6.sin6_addr = pr->ndpr_mask;
 1623         /* rtrequest() will probably set RTF_UP, but we're not sure. */
 1624         rtflags = ifa->ifa_flags | RTF_UP;
 1625         if (nd6_need_cache(ifp)) {
 1626                 /* explicitly set in case ifa_flags does not set the flag. */
 1627                 rtflags |= RTF_CLONING;
 1628         } else {
 1629                 /*
 1630                  * explicitly clear the cloning bit in case ifa_flags sets it.
 1631                  */
 1632                 rtflags &= ~RTF_CLONING;
 1633         }
 1634         error = rtrequest(RTM_ADD, (struct sockaddr *)&pr->ndpr_prefix,
 1635             ifa->ifa_addr, (struct sockaddr *)&mask6, rtflags, &rt);
 1636         if (error == 0) {
 1637                 if (rt != NULL) /* this should be non NULL, though */
 1638                         nd6_rtmsg(RTM_ADD, rt);
 1639                 pr->ndpr_stateflags |= NDPRF_ONLINK;
 1640         } else {
 1641                 nd6log((LOG_ERR, "nd6_prefix_onlink: failed to add route for a"
 1642                     " prefix (%s/%d) on %s, gw=%s, mask=%s, flags=%lx "
 1643                     "errno = %d\n",
 1644                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
 1645                     pr->ndpr_plen, if_name(ifp),
 1646                     ip6_sprintf(&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr),
 1647                     ip6_sprintf(&mask6.sin6_addr), rtflags, error));
 1648         }
 1649 
 1650         if (rt != NULL)
 1651                 rt->rt_refcnt--;
 1652 
 1653         return (error);
 1654 }
 1655 
 1656 int
 1657 nd6_prefix_offlink(pr)
 1658         struct nd_prefix *pr;
 1659 {
 1660         int error = 0;
 1661         struct ifnet *ifp = pr->ndpr_ifp;
 1662         struct nd_prefix *opr;
 1663         struct sockaddr_in6 sa6, mask6;
 1664         struct rtentry *rt = NULL;
 1665 
 1666         /* sanity check */
 1667         if ((pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1668                 nd6log((LOG_ERR,
 1669                     "nd6_prefix_offlink: %s/%d is already off-link\n",
 1670                     ip6_sprintf(&pr->ndpr_prefix.sin6_addr), pr->ndpr_plen));
 1671                 return (EEXIST);
 1672         }
 1673 
 1674         bzero(&sa6, sizeof(sa6));
 1675         sa6.sin6_family = AF_INET6;
 1676         sa6.sin6_len = sizeof(sa6);
 1677         bcopy(&pr->ndpr_prefix.sin6_addr, &sa6.sin6_addr,
 1678             sizeof(struct in6_addr));
 1679         bzero(&mask6, sizeof(mask6));
 1680         mask6.sin6_family = AF_INET6;
 1681         mask6.sin6_len = sizeof(sa6);
 1682         bcopy(&pr->ndpr_mask, &mask6.sin6_addr, sizeof(struct in6_addr));
 1683         error = rtrequest(RTM_DELETE, (struct sockaddr *)&sa6, NULL,
 1684             (struct sockaddr *)&mask6, 0, &rt);
 1685         if (error == 0) {
 1686                 pr->ndpr_stateflags &= ~NDPRF_ONLINK;
 1687 
 1688                 /* report the route deletion to the routing socket. */
 1689                 if (rt != NULL)
 1690                         nd6_rtmsg(RTM_DELETE, rt);
 1691 
 1692                 /*
 1693                  * There might be the same prefix on another interface,
 1694                  * the prefix which could not be on-link just because we have
 1695                  * the interface route (see comments in nd6_prefix_onlink).
 1696                  * If there's one, try to make the prefix on-link on the
 1697                  * interface.
 1698                  */
 1699                 LIST_FOREACH(opr, &nd_prefix, ndpr_entry) {
 1700                         if (opr == pr)
 1701                                 continue;
 1702 
 1703                         if ((opr->ndpr_stateflags & NDPRF_ONLINK) != 0)
 1704                                 continue;
 1705 
 1706                         /*
 1707                          * KAME specific: detached prefixes should not be
 1708                          * on-link.
 1709                          */
 1710                         if ((opr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1711                                 continue;
 1712 
 1713                         if (opr->ndpr_plen == pr->ndpr_plen &&
 1714                             in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1715                             &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
 1716                                 int e;
 1717 
 1718                                 if ((e = nd6_prefix_onlink(opr)) != 0) {
 1719                                         nd6log((LOG_ERR,
 1720                                             "nd6_prefix_offlink: failed to "
 1721                                             "recover a prefix %s/%d from %s "
 1722                                             "to %s (errno = %d)\n",
 1723                                             ip6_sprintf(&opr->ndpr_prefix.sin6_addr),
 1724                                             opr->ndpr_plen, if_name(ifp),
 1725                                             if_name(opr->ndpr_ifp), e));
 1726                                 }
 1727                         }
 1728                 }
 1729         } else {
 1730                 /* XXX: can we still set the NDPRF_ONLINK flag? */
 1731                 nd6log((LOG_ERR,
 1732                     "nd6_prefix_offlink: failed to delete route: "
 1733                     "%s/%d on %s (errno = %d)\n",
 1734                     ip6_sprintf(&sa6.sin6_addr), pr->ndpr_plen, if_name(ifp),
 1735                     error));
 1736         }
 1737 
 1738         if (rt != NULL) {
 1739                 if (rt->rt_refcnt <= 0) {
 1740                         /* XXX: we should free the entry ourselves. */
 1741                         rt->rt_refcnt++;
 1742                         rtfree(rt);
 1743                 }
 1744         }
 1745 
 1746         return (error);
 1747 }
 1748 
 1749 static struct in6_ifaddr *
 1750 in6_ifadd(pr, mcast)
 1751         struct nd_prefixctl *pr;
 1752         int mcast;
 1753 {
 1754         struct ifnet *ifp = pr->ndpr_ifp;
 1755         struct ifaddr *ifa;
 1756         struct in6_aliasreq ifra;
 1757         struct in6_ifaddr *ia, *ib;
 1758         int error, plen0;
 1759         struct in6_addr mask;
 1760         int prefixlen = pr->ndpr_plen;
 1761         int updateflags;
 1762 
 1763         in6_prefixlen2mask(&mask, prefixlen);
 1764 
 1765         /*
 1766          * find a link-local address (will be interface ID).
 1767          * Is it really mandatory? Theoretically, a global or a site-local
 1768          * address can be configured without a link-local address, if we
 1769          * have a unique interface identifier...
 1770          *
 1771          * it is not mandatory to have a link-local address, we can generate
 1772          * interface identifier on the fly.  we do this because:
 1773          * (1) it should be the easiest way to find interface identifier.
 1774          * (2) RFC2462 5.4 suggesting the use of the same interface identifier
 1775          * for multiple addresses on a single interface, and possible shortcut
 1776          * of DAD.  we omitted DAD for this reason in the past.
 1777          * (3) a user can prevent autoconfiguration of global address
 1778          * by removing link-local address by hand (this is partly because we
 1779          * don't have other way to control the use of IPv6 on an interface.
 1780          * this has been our design choice - cf. NRL's "ifconfig auto").
 1781          * (4) it is easier to manage when an interface has addresses
 1782          * with the same interface identifier, than to have multiple addresses
 1783          * with different interface identifiers.
 1784          */
 1785         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0); /* 0 is OK? */
 1786         if (ifa)
 1787                 ib = (struct in6_ifaddr *)ifa;
 1788         else
 1789                 return NULL;
 1790 
 1791 #if 0 /* don't care link local addr state, and always do DAD */
 1792         /* if link-local address is not eligible, do not autoconfigure. */
 1793         if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_NOTREADY) {
 1794                 printf("in6_ifadd: link-local address not ready\n");
 1795                 return NULL;
 1796         }
 1797 #endif
 1798 
 1799         /* prefixlen + ifidlen must be equal to 128 */
 1800         plen0 = in6_mask2len(&ib->ia_prefixmask.sin6_addr, NULL);
 1801         if (prefixlen != plen0) {
 1802                 nd6log((LOG_INFO, "in6_ifadd: wrong prefixlen for %s "
 1803                     "(prefix=%d ifid=%d)\n",
 1804                     if_name(ifp), prefixlen, 128 - plen0));
 1805                 return NULL;
 1806         }
 1807 
 1808         /* make ifaddr */
 1809 
 1810         memset(&ifra, 0, sizeof(ifra));
 1811         /*
 1812          * in6_update_ifa() does not use ifra_name, but we accurately set it
 1813          * for safety.
 1814          */
 1815         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1816         ifra.ifra_addr.sin6_family = AF_INET6;
 1817         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
 1818         /* prefix */
 1819         ifra.ifra_addr.sin6_addr = pr->ndpr_prefix.sin6_addr;
 1820         ifra.ifra_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
 1821         ifra.ifra_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
 1822         ifra.ifra_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
 1823         ifra.ifra_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
 1824 
 1825         /* interface ID */
 1826         ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
 1827             (ib->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
 1828         ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
 1829             (ib->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
 1830         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1831             (ib->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
 1832         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1833             (ib->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);
 1834 
 1835         /* new prefix mask. */
 1836         ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
 1837         ifra.ifra_prefixmask.sin6_family = AF_INET6;
 1838         bcopy(&mask, &ifra.ifra_prefixmask.sin6_addr,
 1839             sizeof(ifra.ifra_prefixmask.sin6_addr));
 1840 
 1841         /* lifetimes */
 1842         ifra.ifra_lifetime.ia6t_vltime = pr->ndpr_vltime;
 1843         ifra.ifra_lifetime.ia6t_pltime = pr->ndpr_pltime;
 1844 
 1845         /* XXX: scope zone ID? */
 1846 
 1847         ifra.ifra_flags |= IN6_IFF_AUTOCONF; /* obey autoconf */
 1848 
 1849         /*
 1850          * Make sure that we do not have this address already.  This should
 1851          * usually not happen, but we can still see this case, e.g., if we
 1852          * have manually configured the exact address to be configured.
 1853          */
 1854         if (in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr) != NULL) {
 1855                 /* this should be rare enough to make an explicit log */
 1856                 log(LOG_INFO, "in6_ifadd: %s is already configured\n",
 1857                     ip6_sprintf(&ifra.ifra_addr.sin6_addr));
 1858                 return (NULL);
 1859         }
 1860 
 1861         /*
 1862          * Allocate ifaddr structure, link into chain, etc.
 1863          * If we are going to create a new address upon receiving a multicasted
 1864          * RA, we need to impose a random delay before starting DAD.
 1865          * [draft-ietf-ipv6-rfc2462bis-02.txt, Section 5.4.2]
 1866          */
 1867         updateflags = 0;
 1868         if (mcast)
 1869                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1870         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0) {
 1871                 nd6log((LOG_ERR,
 1872                     "in6_ifadd: failed to make ifaddr %s on %s (errno=%d)\n",
 1873                     ip6_sprintf(&ifra.ifra_addr.sin6_addr), if_name(ifp),
 1874                     error));
 1875                 return (NULL);  /* ifaddr must not have been allocated. */
 1876         }
 1877 
 1878         ia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1879 
 1880         return (ia);            /* this is always non-NULL */
 1881 }
 1882 
 1883 int
 1884 in6_tmpifadd(ia0, forcegen, dad_delay)
 1885         const struct in6_ifaddr *ia0; /* corresponding public address */
 1886         int forcegen, dad_delay;
 1887 {
 1888         struct ifnet *ifp = ia0->ia_ifa.ifa_ifp;
 1889         struct in6_ifaddr *newia, *ia;
 1890         struct in6_aliasreq ifra;
 1891         int i, error;
 1892         int trylimit = 3;       /* XXX: adhoc value */
 1893         int updateflags;
 1894         u_int32_t randid[2];
 1895         u_int32_t vltime0, pltime0;
 1896 
 1897         memset(&ifra, 0, sizeof(ifra));
 1898         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1899         ifra.ifra_addr = ia0->ia_addr;
 1900         /* copy prefix mask */
 1901         ifra.ifra_prefixmask = ia0->ia_prefixmask;
 1902         /* clear the old IFID */
 1903         for (i = 0; i < 4; i++) {
 1904                 ifra.ifra_addr.sin6_addr.s6_addr32[i] &=
 1905                     ifra.ifra_prefixmask.sin6_addr.s6_addr32[i];
 1906         }
 1907 
 1908   again:
 1909         if (in6_get_tmpifid(ifp, (u_int8_t *)randid,
 1910             (const u_int8_t *)&ia0->ia_addr.sin6_addr.s6_addr[8], forcegen)) {
 1911                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to find a good "
 1912                     "random IFID\n"));
 1913                 return (EINVAL);
 1914         }
 1915         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1916             (randid[0] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[2]));
 1917         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1918             (randid[1] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[3]));
 1919 
 1920         /*
 1921          * in6_get_tmpifid() quite likely provided a unique interface ID.
 1922          * However, we may still have a chance to see collision, because
 1923          * there may be a time lag between generation of the ID and generation
 1924          * of the address.  So, we'll do one more sanity check.
 1925          */
 1926         for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
 1927                 if (IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
 1928                     &ifra.ifra_addr.sin6_addr)) {
 1929                         if (trylimit-- == 0) {
 1930                                 /*
 1931                                  * Give up.  Something strange should have
 1932                                  * happened.
 1933                                  */
 1934                                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to "
 1935                                     "find a unique random IFID\n"));
 1936                                 return (EEXIST);
 1937                         }
 1938                         forcegen = 1;
 1939                         goto again;
 1940                 }
 1941         }
 1942 
 1943         /*
 1944          * The Valid Lifetime is the lower of the Valid Lifetime of the
 1945          * public address or TEMP_VALID_LIFETIME.
 1946          * The Preferred Lifetime is the lower of the Preferred Lifetime
 1947          * of the public address or TEMP_PREFERRED_LIFETIME -
 1948          * DESYNC_FACTOR.
 1949          */
 1950         if (ia0->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
 1951                 vltime0 = IFA6_IS_INVALID(ia0) ? 0 :
 1952                     (ia0->ia6_lifetime.ia6t_vltime -
 1953                     (time_second - ia0->ia6_updatetime));
 1954                 if (vltime0 > ip6_temp_valid_lifetime)
 1955                         vltime0 = ip6_temp_valid_lifetime;
 1956         } else
 1957                 vltime0 = ip6_temp_valid_lifetime;
 1958         if (ia0->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
 1959                 pltime0 = IFA6_IS_DEPRECATED(ia0) ? 0 :
 1960                     (ia0->ia6_lifetime.ia6t_pltime -
 1961                     (time_second - ia0->ia6_updatetime));
 1962                 if (pltime0 > ip6_temp_preferred_lifetime - ip6_desync_factor){
 1963                         pltime0 = ip6_temp_preferred_lifetime -
 1964                             ip6_desync_factor;
 1965                 }
 1966         } else
 1967                 pltime0 = ip6_temp_preferred_lifetime - ip6_desync_factor;
 1968         ifra.ifra_lifetime.ia6t_vltime = vltime0;
 1969         ifra.ifra_lifetime.ia6t_pltime = pltime0;
 1970 
 1971         /*
 1972          * A temporary address is created only if this calculated Preferred
 1973          * Lifetime is greater than REGEN_ADVANCE time units.
 1974          */
 1975         if (ifra.ifra_lifetime.ia6t_pltime <= ip6_temp_regen_advance)
 1976                 return (0);
 1977 
 1978         /* XXX: scope zone ID? */
 1979 
 1980         ifra.ifra_flags |= (IN6_IFF_AUTOCONF|IN6_IFF_TEMPORARY);
 1981 
 1982         /* allocate ifaddr structure, link into chain, etc. */
 1983         updateflags = 0;
 1984         if (dad_delay)
 1985                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1986         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0)
 1987                 return (error);
 1988 
 1989         newia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1990         if (newia == NULL) {    /* XXX: can it happen? */
 1991                 nd6log((LOG_ERR,
 1992                     "in6_tmpifadd: ifa update succeeded, but we got "
 1993                     "no ifaddr\n"));
 1994                 return (EINVAL); /* XXX */
 1995         }
 1996         newia->ia6_ndpr = ia0->ia6_ndpr;
 1997         newia->ia6_ndpr->ndpr_refcnt++;
 1998 
 1999         /*
 2000          * A newly added address might affect the status of other addresses.
 2001          * XXX: when the temporary address is generated with a new public
 2002          * address, the onlink check is redundant.  However, it would be safe
 2003          * to do the check explicitly everywhere a new address is generated,
 2004          * and, in fact, we surely need the check when we create a new
 2005          * temporary address due to deprecation of an old temporary address.
 2006          */
 2007         pfxlist_onlink_check();
 2008 
 2009         return (0);
 2010 }
 2011 
 2012 static int
 2013 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
 2014 {
 2015 
 2016         /* check if preferred lifetime > valid lifetime.  RFC2462 5.5.3 (c) */
 2017         if (ndpr->ndpr_pltime > ndpr->ndpr_vltime) {
 2018                 nd6log((LOG_INFO, "in6_init_prefix_ltimes: preferred lifetime"
 2019                     "(%d) is greater than valid lifetime(%d)\n",
 2020                     (u_int)ndpr->ndpr_pltime, (u_int)ndpr->ndpr_vltime));
 2021                 return (EINVAL);
 2022         }
 2023         if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
 2024                 ndpr->ndpr_preferred = 0;
 2025         else
 2026                 ndpr->ndpr_preferred = time_second + ndpr->ndpr_pltime;
 2027         if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
 2028                 ndpr->ndpr_expire = 0;
 2029         else
 2030                 ndpr->ndpr_expire = time_second + ndpr->ndpr_vltime;
 2031 
 2032         return 0;
 2033 }
 2034 
 2035 static void
 2036 in6_init_address_ltimes(struct nd_prefix *new,
 2037     struct in6_addrlifetime *lt6)
 2038 {
 2039 
 2040         /* Valid lifetime must not be updated unless explicitly specified. */
 2041         /* init ia6t_expire */
 2042         if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
 2043                 lt6->ia6t_expire = 0;
 2044         else {
 2045                 lt6->ia6t_expire = time_second;
 2046                 lt6->ia6t_expire += lt6->ia6t_vltime;
 2047         }
 2048 
 2049         /* init ia6t_preferred */
 2050         if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
 2051                 lt6->ia6t_preferred = 0;
 2052         else {
 2053                 lt6->ia6t_preferred = time_second;
 2054                 lt6->ia6t_preferred += lt6->ia6t_pltime;
 2055         }
 2056 }
 2057 
 2058 /*
 2059  * Delete all the routing table entries that use the specified gateway.
 2060  * XXX: this function causes search through all entries of routing table, so
 2061  * it shouldn't be called when acting as a router.
 2062  */
 2063 void
 2064 rt6_flush(struct in6_addr *gateway, struct ifnet *ifp)
 2065 {
 2066         struct radix_node_head *rnh = rt_tables[AF_INET6];
 2067         int s = splsoftnet();
 2068 
 2069         /* We'll care only link-local addresses */
 2070         if (!IN6_IS_ADDR_LINKLOCAL(gateway)) {
 2071                 splx(s);
 2072                 return;
 2073         }
 2074 
 2075         rnh->rnh_walktree(rnh, rt6_deleteroute, (void *)gateway);
 2076         splx(s);
 2077 }
 2078 
 2079 static int
 2080 rt6_deleteroute(rn, arg)
 2081         struct radix_node *rn;
 2082         void *arg;
 2083 {
 2084 #define SIN6(s) ((struct sockaddr_in6 *)s)
 2085         struct rtentry *rt = (struct rtentry *)rn;
 2086         struct in6_addr *gate = (struct in6_addr *)arg;
 2087 
 2088         if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
 2089                 return (0);
 2090 
 2091         if (!IN6_ARE_ADDR_EQUAL(gate, &SIN6(rt->rt_gateway)->sin6_addr))
 2092                 return (0);
 2093 
 2094         /*
 2095          * Do not delete a static route.
 2096          * XXX: this seems to be a bit ad-hoc. Should we consider the
 2097          * 'cloned' bit instead?
 2098          */
 2099         if ((rt->rt_flags & RTF_STATIC) != 0)
 2100                 return (0);
 2101 
 2102         /*
 2103          * We delete only host route. This means, in particular, we don't
 2104          * delete default route.
 2105          */
 2106         if ((rt->rt_flags & RTF_HOST) == 0)
 2107                 return (0);
 2108 
 2109         return (rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
 2110             rt_mask(rt), rt->rt_flags, 0));
 2111 #undef SIN6
 2112 }
 2113 
 2114 int
 2115 nd6_setdefaultiface(ifindex)
 2116         int ifindex;
 2117 {
 2118         int error = 0;
 2119 
 2120         if (ifindex < 0 || if_indexlim <= ifindex)
 2121                 return (EINVAL);
 2122         if (ifindex != 0 && !ifindex2ifnet[ifindex])
 2123                 return (EINVAL);
 2124 
 2125         if (nd6_defifindex != ifindex) {
 2126                 nd6_defifindex = ifindex;
 2127                 if (nd6_defifindex > 0) {
 2128                         nd6_defifp = ifindex2ifnet[nd6_defifindex];
 2129                 } else
 2130                         nd6_defifp = NULL;
 2131 
 2132                 /*
 2133                  * Our current implementation assumes one-to-one maping between
 2134                  * interfaces and links, so it would be natural to use the
 2135                  * default interface as the default link.
 2136                  */
 2137                 scope6_setdefault(nd6_defifp);
 2138         }
 2139 
 2140         return (error);
 2141 }

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