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

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    1 /*-
    2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 3. Neither the name of the project nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      $KAME: nd6_rtr.c,v 1.111 2001/04/27 01:37:15 jinmei Exp $
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/8.2/sys/netinet6/nd6_rtr.c 207695 2010-05-06 06:44:19Z bz $");
   34 
   35 #include "opt_inet.h"
   36 #include "opt_inet6.h"
   37 
   38 #include <sys/param.h>
   39 #include <sys/systm.h>
   40 #include <sys/malloc.h>
   41 #include <sys/mbuf.h>
   42 #include <sys/socket.h>
   43 #include <sys/sockio.h>
   44 #include <sys/time.h>
   45 #include <sys/kernel.h>
   46 #include <sys/lock.h>
   47 #include <sys/errno.h>
   48 #include <sys/rwlock.h>
   49 #include <sys/syslog.h>
   50 #include <sys/queue.h>
   51 
   52 #include <net/if.h>
   53 #include <net/if_types.h>
   54 #include <net/if_dl.h>
   55 #include <net/route.h>
   56 #include <net/radix.h>
   57 #include <net/vnet.h>
   58 
   59 #include <netinet/in.h>
   60 #include <net/if_llatbl.h>
   61 #include <netinet6/in6_var.h>
   62 #include <netinet6/in6_ifattach.h>
   63 #include <netinet/ip6.h>
   64 #include <netinet6/ip6_var.h>
   65 #include <netinet6/nd6.h>
   66 #include <netinet/icmp6.h>
   67 #include <netinet6/scope6_var.h>
   68 
   69 static int rtpref(struct nd_defrouter *);
   70 static struct nd_defrouter *defrtrlist_update(struct nd_defrouter *);
   71 static int prelist_update __P((struct nd_prefixctl *, struct nd_defrouter *,
   72     struct mbuf *, int));
   73 static struct in6_ifaddr *in6_ifadd(struct nd_prefixctl *,      int);
   74 static struct nd_pfxrouter *pfxrtr_lookup __P((struct nd_prefix *,
   75         struct nd_defrouter *));
   76 static void pfxrtr_add(struct nd_prefix *, struct nd_defrouter *);
   77 static void pfxrtr_del(struct nd_pfxrouter *);
   78 static struct nd_pfxrouter *find_pfxlist_reachable_router
   79 (struct nd_prefix *);
   80 static void defrouter_delreq(struct nd_defrouter *);
   81 static void nd6_rtmsg(int, struct rtentry *);
   82 
   83 static int in6_init_prefix_ltimes(struct nd_prefix *);
   84 static void in6_init_address_ltimes __P((struct nd_prefix *,
   85         struct in6_addrlifetime *));
   86 
   87 static int rt6_deleteroute(struct radix_node *, void *);
   88 
   89 VNET_DECLARE(int, nd6_recalc_reachtm_interval);
   90 #define V_nd6_recalc_reachtm_interval   VNET(nd6_recalc_reachtm_interval)
   91 
   92 static VNET_DEFINE(struct ifnet *, nd6_defifp);
   93 VNET_DEFINE(int, nd6_defifindex);
   94 #define V_nd6_defifp                    VNET(nd6_defifp)
   95 
   96 VNET_DEFINE(int, ip6_use_tempaddr) = 0;
   97 
   98 VNET_DEFINE(int, ip6_desync_factor);
   99 VNET_DEFINE(u_int32_t, ip6_temp_preferred_lifetime) = DEF_TEMP_PREFERRED_LIFETIME;
  100 VNET_DEFINE(u_int32_t, ip6_temp_valid_lifetime) = DEF_TEMP_VALID_LIFETIME;
  101 
  102 VNET_DEFINE(int, ip6_temp_regen_advance) = TEMPADDR_REGEN_ADVANCE;
  103 
  104 /* RTPREF_MEDIUM has to be 0! */
  105 #define RTPREF_HIGH     1
  106 #define RTPREF_MEDIUM   0
  107 #define RTPREF_LOW      (-1)
  108 #define RTPREF_RESERVED (-2)
  109 #define RTPREF_INVALID  (-3)    /* internal */
  110 
  111 /*
  112  * Receive Router Solicitation Message - just for routers.
  113  * Router solicitation/advertisement is mostly managed by userland program
  114  * (rtadvd) so here we have no function like nd6_ra_output().
  115  *
  116  * Based on RFC 2461
  117  */
  118 void
  119 nd6_rs_input(struct mbuf *m, int off, int icmp6len)
  120 {
  121         struct ifnet *ifp = m->m_pkthdr.rcvif;
  122         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  123         struct nd_router_solicit *nd_rs;
  124         struct in6_addr saddr6 = ip6->ip6_src;
  125         char *lladdr = NULL;
  126         int lladdrlen = 0;
  127         union nd_opts ndopts;
  128         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  129 
  130         /* If I'm not a router, ignore it. */
  131         if (V_ip6_accept_rtadv != 0 || V_ip6_forwarding != 1)
  132                 goto freeit;
  133 
  134         /* Sanity checks */
  135         if (ip6->ip6_hlim != 255) {
  136                 nd6log((LOG_ERR,
  137                     "nd6_rs_input: invalid hlim (%d) from %s to %s on %s\n",
  138                     ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  139                     ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
  140                 goto bad;
  141         }
  142 
  143         /*
  144          * Don't update the neighbor cache, if src = ::.
  145          * This indicates that the src has no IP address assigned yet.
  146          */
  147         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  148                 goto freeit;
  149 
  150 #ifndef PULLDOWN_TEST
  151         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  152         nd_rs = (struct nd_router_solicit *)((caddr_t)ip6 + off);
  153 #else
  154         IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
  155         if (nd_rs == NULL) {
  156                 ICMP6STAT_INC(icp6s_tooshort);
  157                 return;
  158         }
  159 #endif
  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(ip6bufs, &saddr6),
  180                     ifp->if_addrlen, lladdrlen - 2));
  181                 goto bad;
  182         }
  183 
  184         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
  185 
  186  freeit:
  187         m_freem(m);
  188         return;
  189 
  190  bad:
  191         ICMP6STAT_INC(icp6s_badrs);
  192         m_freem(m);
  193 }
  194 
  195 /*
  196  * Receive Router Advertisement Message.
  197  *
  198  * Based on RFC 2461
  199  * TODO: on-link bit on prefix information
  200  * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
  201  */
  202 void
  203 nd6_ra_input(struct mbuf *m, int off, int icmp6len)
  204 {
  205         struct ifnet *ifp = m->m_pkthdr.rcvif;
  206         struct nd_ifinfo *ndi = ND_IFINFO(ifp);
  207         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  208         struct nd_router_advert *nd_ra;
  209         struct in6_addr saddr6 = ip6->ip6_src;
  210         int mcast = 0;
  211         union nd_opts ndopts;
  212         struct nd_defrouter *dr;
  213         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  214 
  215         /*
  216          * We only accept RAs only when
  217          * the system-wide variable allows the acceptance, and
  218          * per-interface variable allows RAs on the receiving interface.
  219          */
  220         if (V_ip6_accept_rtadv == 0)
  221                 goto freeit;
  222         if (!(ndi->flags & ND6_IFF_ACCEPT_RTADV))
  223                 goto freeit;
  224 
  225         if (ip6->ip6_hlim != 255) {
  226                 nd6log((LOG_ERR,
  227                     "nd6_ra_input: invalid hlim (%d) from %s to %s on %s\n",
  228                     ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  229                     ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
  230                 goto bad;
  231         }
  232 
  233         if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
  234                 nd6log((LOG_ERR,
  235                     "nd6_ra_input: src %s is not link-local\n",
  236                     ip6_sprintf(ip6bufs, &saddr6)));
  237                 goto bad;
  238         }
  239 
  240 #ifndef PULLDOWN_TEST
  241         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  242         nd_ra = (struct nd_router_advert *)((caddr_t)ip6 + off);
  243 #else
  244         IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
  245         if (nd_ra == NULL) {
  246                 ICMP6STAT_INC(icp6s_tooshort);
  247                 return;
  248         }
  249 #endif
  250 
  251         icmp6len -= sizeof(*nd_ra);
  252         nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
  253         if (nd6_options(&ndopts) < 0) {
  254                 nd6log((LOG_INFO,
  255                     "nd6_ra_input: invalid ND option, ignored\n"));
  256                 /* nd6_options have incremented stats */
  257                 goto freeit;
  258         }
  259 
  260     {
  261         struct nd_defrouter dr0;
  262         u_int32_t advreachable = nd_ra->nd_ra_reachable;
  263 
  264         /* remember if this is a multicasted advertisement */
  265         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
  266                 mcast = 1;
  267 
  268         bzero(&dr0, sizeof(dr0));
  269         dr0.rtaddr = saddr6;
  270         dr0.flags  = nd_ra->nd_ra_flags_reserved;
  271         dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
  272         dr0.expire = time_second + dr0.rtlifetime;
  273         dr0.ifp = ifp;
  274         /* unspecified or not? (RFC 2461 6.3.4) */
  275         if (advreachable) {
  276                 advreachable = ntohl(advreachable);
  277                 if (advreachable <= MAX_REACHABLE_TIME &&
  278                     ndi->basereachable != advreachable) {
  279                         ndi->basereachable = advreachable;
  280                         ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
  281                         ndi->recalctm = V_nd6_recalc_reachtm_interval; /* reset */
  282                 }
  283         }
  284         if (nd_ra->nd_ra_retransmit)
  285                 ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
  286         if (nd_ra->nd_ra_curhoplimit)
  287                 ndi->chlim = nd_ra->nd_ra_curhoplimit;
  288         dr = defrtrlist_update(&dr0);
  289     }
  290 
  291         /*
  292          * prefix
  293          */
  294         if (ndopts.nd_opts_pi) {
  295                 struct nd_opt_hdr *pt;
  296                 struct nd_opt_prefix_info *pi = NULL;
  297                 struct nd_prefixctl pr;
  298 
  299                 for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
  300                      pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
  301                      pt = (struct nd_opt_hdr *)((caddr_t)pt +
  302                                                 (pt->nd_opt_len << 3))) {
  303                         if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
  304                                 continue;
  305                         pi = (struct nd_opt_prefix_info *)pt;
  306 
  307                         if (pi->nd_opt_pi_len != 4) {
  308                                 nd6log((LOG_INFO,
  309                                     "nd6_ra_input: invalid option "
  310                                     "len %d for prefix information option, "
  311                                     "ignored\n", pi->nd_opt_pi_len));
  312                                 continue;
  313                         }
  314 
  315                         if (128 < pi->nd_opt_pi_prefix_len) {
  316                                 nd6log((LOG_INFO,
  317                                     "nd6_ra_input: invalid prefix "
  318                                     "len %d for prefix information option, "
  319                                     "ignored\n", pi->nd_opt_pi_prefix_len));
  320                                 continue;
  321                         }
  322 
  323                         if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
  324                          || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
  325                                 nd6log((LOG_INFO,
  326                                     "nd6_ra_input: invalid prefix "
  327                                     "%s, ignored\n",
  328                                     ip6_sprintf(ip6bufs,
  329                                         &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                         (void)prelist_update(&pr, dr, m, mcast);
  347                 }
  348         }
  349 
  350         /*
  351          * MTU
  352          */
  353         if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
  354                 u_long mtu;
  355                 u_long maxmtu;
  356 
  357                 mtu = (u_long)ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
  358 
  359                 /* lower bound */
  360                 if (mtu < IPV6_MMTU) {
  361                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
  362                             "mtu=%lu sent from %s, ignoring\n",
  363                             mtu, ip6_sprintf(ip6bufs, &ip6->ip6_src)));
  364                         goto skip;
  365                 }
  366 
  367                 /* upper bound */
  368                 maxmtu = (ndi->maxmtu && ndi->maxmtu < ifp->if_mtu)
  369                     ? ndi->maxmtu : ifp->if_mtu;
  370                 if (mtu <= maxmtu) {
  371                         int change = (ndi->linkmtu != mtu);
  372 
  373                         ndi->linkmtu = mtu;
  374                         if (change) /* in6_maxmtu may change */
  375                                 in6_setmaxmtu();
  376                 } else {
  377                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
  378                             "mtu=%lu sent from %s; "
  379                             "exceeds maxmtu %lu, ignoring\n",
  380                             mtu, ip6_sprintf(ip6bufs, &ip6->ip6_src), maxmtu));
  381                 }
  382         }
  383 
  384  skip:
  385 
  386         /*
  387          * Source link layer address
  388          */
  389     {
  390         char *lladdr = NULL;
  391         int lladdrlen = 0;
  392 
  393         if (ndopts.nd_opts_src_lladdr) {
  394                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  395                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  396         }
  397 
  398         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  399                 nd6log((LOG_INFO,
  400                     "nd6_ra_input: lladdrlen mismatch for %s "
  401                     "(if %d, RA packet %d)\n", ip6_sprintf(ip6bufs, &saddr6),
  402                     ifp->if_addrlen, lladdrlen - 2));
  403                 goto bad;
  404         }
  405 
  406         nd6_cache_lladdr(ifp, &saddr6, lladdr,
  407             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_INC(icp6s_badra);
  423         m_freem(m);
  424 }
  425 
  426 /*
  427  * default router list proccessing sub routines
  428  */
  429 
  430 /* tell the change to user processes watching the routing socket. */
  431 static void
  432 nd6_rtmsg(int cmd, struct rtentry *rt)
  433 {
  434         struct rt_addrinfo info;
  435         struct ifnet *ifp;
  436         struct ifaddr *ifa;
  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         ifp = rt->rt_ifp;
  443         if (ifp != NULL) {
  444                 IF_ADDR_LOCK(ifp);
  445                 ifa = TAILQ_FIRST(&ifp->if_addrhead);
  446                 info.rti_info[RTAX_IFP] = ifa->ifa_addr;
  447                 ifa_ref(ifa);
  448                 IF_ADDR_UNLOCK(ifp);
  449                 info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
  450         } else
  451                 ifa = NULL;
  452 
  453         rt_missmsg(cmd, &info, rt->rt_flags, 0);
  454         if (ifa != NULL)
  455                 ifa_free(ifa);
  456 }
  457 
  458 void
  459 defrouter_addreq(struct nd_defrouter *new)
  460 {
  461         struct sockaddr_in6 def, mask, gate;
  462         struct rtentry *newrt = NULL;
  463         int s;
  464         int error;
  465 
  466         bzero(&def, sizeof(def));
  467         bzero(&mask, sizeof(mask));
  468         bzero(&gate, sizeof(gate));
  469 
  470         def.sin6_len = mask.sin6_len = gate.sin6_len =
  471             sizeof(struct sockaddr_in6);
  472         def.sin6_family = gate.sin6_family = AF_INET6;
  473         gate.sin6_addr = new->rtaddr;
  474 
  475         s = splnet();
  476         error = rtrequest(RTM_ADD, (struct sockaddr *)&def,
  477             (struct sockaddr *)&gate, (struct sockaddr *)&mask,
  478             RTF_GATEWAY, &newrt);
  479         if (newrt) {
  480                 nd6_rtmsg(RTM_ADD, newrt); /* tell user process */
  481                 RTFREE(newrt);
  482         }
  483         if (error == 0)
  484                 new->installed = 1;
  485         splx(s);
  486         return;
  487 }
  488 
  489 struct nd_defrouter *
  490 defrouter_lookup(struct in6_addr *addr, struct ifnet *ifp)
  491 {
  492         struct nd_defrouter *dr;
  493 
  494         for (dr = TAILQ_FIRST(&V_nd_defrouter); dr;
  495              dr = TAILQ_NEXT(dr, dr_entry)) {
  496                 if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr))
  497                         return (dr);
  498         }
  499 
  500         return (NULL);          /* search failed */
  501 }
  502 
  503 /*
  504  * Remove the default route for a given router.
  505  * This is just a subroutine function for defrouter_select(), and should
  506  * not be called from anywhere else.
  507  */
  508 static void
  509 defrouter_delreq(struct nd_defrouter *dr)
  510 {
  511         struct sockaddr_in6 def, mask, gate;
  512         struct rtentry *oldrt = NULL;
  513 
  514         bzero(&def, sizeof(def));
  515         bzero(&mask, sizeof(mask));
  516         bzero(&gate, sizeof(gate));
  517 
  518         def.sin6_len = mask.sin6_len = gate.sin6_len =
  519             sizeof(struct sockaddr_in6);
  520         def.sin6_family = gate.sin6_family = AF_INET6;
  521         gate.sin6_addr = dr->rtaddr;
  522 
  523         rtrequest(RTM_DELETE, (struct sockaddr *)&def,
  524             (struct sockaddr *)&gate,
  525             (struct sockaddr *)&mask, RTF_GATEWAY, &oldrt);
  526         if (oldrt) {
  527                 nd6_rtmsg(RTM_DELETE, oldrt);
  528                 RTFREE(oldrt);
  529         }
  530 
  531         dr->installed = 0;
  532 }
  533 
  534 /*
  535  * remove all default routes from default router list
  536  */
  537 void
  538 defrouter_reset(void)
  539 {
  540         struct nd_defrouter *dr;
  541 
  542         for (dr = TAILQ_FIRST(&V_nd_defrouter); dr;
  543              dr = TAILQ_NEXT(dr, dr_entry))
  544                 defrouter_delreq(dr);
  545 
  546         /*
  547          * XXX should we also nuke any default routers in the kernel, by
  548          * going through them by rtalloc1()?
  549          */
  550 }
  551 
  552 void
  553 defrtrlist_del(struct nd_defrouter *dr)
  554 {
  555         struct nd_defrouter *deldr = NULL;
  556         struct nd_prefix *pr;
  557 
  558         /*
  559          * Flush all the routing table entries that use the router
  560          * as a next hop.
  561          */
  562         if (!V_ip6_forwarding && V_ip6_accept_rtadv) /* XXX: better condition? */
  563                 rt6_flush(&dr->rtaddr, dr->ifp);
  564 
  565         if (dr->installed) {
  566                 deldr = dr;
  567                 defrouter_delreq(dr);
  568         }
  569         TAILQ_REMOVE(&V_nd_defrouter, dr, dr_entry);
  570 
  571         /*
  572          * Also delete all the pointers to the router in each prefix lists.
  573          */
  574         for (pr = V_nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
  575                 struct nd_pfxrouter *pfxrtr;
  576                 if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
  577                         pfxrtr_del(pfxrtr);
  578         }
  579         pfxlist_onlink_check();
  580 
  581         /*
  582          * If the router is the primary one, choose a new one.
  583          * Note that defrouter_select() will remove the current gateway
  584          * from the routing table.
  585          */
  586         if (deldr)
  587                 defrouter_select();
  588 
  589         free(dr, M_IP6NDP);
  590 }
  591 
  592 /*
  593  * Default Router Selection according to Section 6.3.6 of RFC 2461 and
  594  * draft-ietf-ipngwg-router-selection:
  595  * 1) Routers that are reachable or probably reachable should be preferred.
  596  *    If we have more than one (probably) reachable router, prefer ones
  597  *    with the highest router preference.
  598  * 2) When no routers on the list are known to be reachable or
  599  *    probably reachable, routers SHOULD be selected in a round-robin
  600  *    fashion, regardless of router preference values.
  601  * 3) If the Default Router List is empty, assume that all
  602  *    destinations are on-link.
  603  *
  604  * We assume nd_defrouter is sorted by router preference value.
  605  * Since the code below covers both with and without router preference cases,
  606  * we do not need to classify the cases by ifdef.
  607  *
  608  * At this moment, we do not try to install more than one default router,
  609  * even when the multipath routing is available, because we're not sure about
  610  * the benefits for stub hosts comparing to the risk of making the code
  611  * complicated and the possibility of introducing bugs.
  612  */
  613 void
  614 defrouter_select(void)
  615 {
  616         int s = splnet();
  617         struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
  618         struct llentry *ln = NULL;
  619 
  620         /*
  621          * This function should be called only when acting as an autoconfigured
  622          * host.  Although the remaining part of this function is not effective
  623          * if the node is not an autoconfigured host, we explicitly exclude
  624          * such cases here for safety.
  625          */
  626         if (V_ip6_forwarding || !V_ip6_accept_rtadv) {
  627                 nd6log((LOG_WARNING,
  628                     "defrouter_select: called unexpectedly (forwarding=%d, "
  629                     "accept_rtadv=%d)\n", V_ip6_forwarding, V_ip6_accept_rtadv));
  630                 splx(s);
  631                 return;
  632         }
  633 
  634         /*
  635          * Let's handle easy case (3) first:
  636          * If default router list is empty, there's nothing to be done.
  637          */
  638         if (!TAILQ_FIRST(&V_nd_defrouter)) {
  639                 splx(s);
  640                 return;
  641         }
  642 
  643         /*
  644          * Search for a (probably) reachable router from the list.
  645          * We just pick up the first reachable one (if any), assuming that
  646          * the ordering rule of the list described in defrtrlist_update().
  647          */
  648         for (dr = TAILQ_FIRST(&V_nd_defrouter); dr;
  649              dr = TAILQ_NEXT(dr, dr_entry)) {
  650                 IF_AFDATA_LOCK(dr->ifp);
  651                 if (selected_dr == NULL &&
  652                     (ln = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) &&
  653                     ND6_IS_LLINFO_PROBREACH(ln)) {
  654                         selected_dr = dr;
  655                 }
  656                 IF_AFDATA_UNLOCK(dr->ifp);
  657                 if (ln != NULL) {
  658                         LLE_RUNLOCK(ln);
  659                         ln = NULL;
  660                 }
  661 
  662                 if (dr->installed && installed_dr == NULL)
  663                         installed_dr = dr;
  664                 else if (dr->installed && installed_dr) {
  665                         /* this should not happen.  warn for diagnosis. */
  666                         log(LOG_ERR, "defrouter_select: more than one router"
  667                             " is installed\n");
  668                 }
  669         }
  670         /*
  671          * If none of the default routers was found to be reachable,
  672          * round-robin the list regardless of preference.
  673          * Otherwise, if we have an installed router, check if the selected
  674          * (reachable) router should really be preferred to the installed one.
  675          * We only prefer the new router when the old one is not reachable
  676          * or when the new one has a really higher preference value.
  677          */
  678         if (selected_dr == NULL) {
  679                 if (installed_dr == NULL || !TAILQ_NEXT(installed_dr, dr_entry))
  680                         selected_dr = TAILQ_FIRST(&V_nd_defrouter);
  681                 else
  682                         selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
  683         } else if (installed_dr) {
  684                 IF_AFDATA_LOCK(installed_dr->ifp);
  685                 if ((ln = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp)) &&
  686                     ND6_IS_LLINFO_PROBREACH(ln) &&
  687                     rtpref(selected_dr) <= rtpref(installed_dr)) {
  688                         selected_dr = installed_dr;
  689                 }
  690                 IF_AFDATA_UNLOCK(installed_dr->ifp);
  691                 if (ln != NULL)
  692                         LLE_RUNLOCK(ln);
  693         }
  694 
  695         /*
  696          * If the selected router is different than the installed one,
  697          * remove the installed router and install the selected one.
  698          * Note that the selected router is never NULL here.
  699          */
  700         if (installed_dr != selected_dr) {
  701                 if (installed_dr)
  702                         defrouter_delreq(installed_dr);
  703                 defrouter_addreq(selected_dr);
  704         }
  705 
  706         splx(s);
  707         return;
  708 }
  709 
  710 /*
  711  * for default router selection
  712  * regards router-preference field as a 2-bit signed integer
  713  */
  714 static int
  715 rtpref(struct nd_defrouter *dr)
  716 {
  717         switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
  718         case ND_RA_FLAG_RTPREF_HIGH:
  719                 return (RTPREF_HIGH);
  720         case ND_RA_FLAG_RTPREF_MEDIUM:
  721         case ND_RA_FLAG_RTPREF_RSV:
  722                 return (RTPREF_MEDIUM);
  723         case ND_RA_FLAG_RTPREF_LOW:
  724                 return (RTPREF_LOW);
  725         default:
  726                 /*
  727                  * This case should never happen.  If it did, it would mean a
  728                  * serious bug of kernel internal.  We thus always bark here.
  729                  * Or, can we even panic?
  730                  */
  731                 log(LOG_ERR, "rtpref: impossible RA flag %x\n", dr->flags);
  732                 return (RTPREF_INVALID);
  733         }
  734         /* NOTREACHED */
  735 }
  736 
  737 static struct nd_defrouter *
  738 defrtrlist_update(struct nd_defrouter *new)
  739 {
  740         struct nd_defrouter *dr, *n;
  741         int s = splnet();
  742 
  743         if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
  744                 /* entry exists */
  745                 if (new->rtlifetime == 0) {
  746                         defrtrlist_del(dr);
  747                         dr = NULL;
  748                 } else {
  749                         int oldpref = rtpref(dr);
  750 
  751                         /* override */
  752                         dr->flags = new->flags; /* xxx flag check */
  753                         dr->rtlifetime = new->rtlifetime;
  754                         dr->expire = new->expire;
  755 
  756                         /*
  757                          * If the preference does not change, there's no need
  758                          * to sort the entries.
  759                          */
  760                         if (rtpref(new) == oldpref) {
  761                                 splx(s);
  762                                 return (dr);
  763                         }
  764 
  765                         /*
  766                          * preferred router may be changed, so relocate
  767                          * this router.
  768                          * XXX: calling TAILQ_REMOVE directly is a bad manner.
  769                          * However, since defrtrlist_del() has many side
  770                          * effects, we intentionally do so here.
  771                          * defrouter_select() below will handle routing
  772                          * changes later.
  773                          */
  774                         TAILQ_REMOVE(&V_nd_defrouter, dr, dr_entry);
  775                         n = dr;
  776                         goto insert;
  777                 }
  778                 splx(s);
  779                 return (dr);
  780         }
  781 
  782         /* entry does not exist */
  783         if (new->rtlifetime == 0) {
  784                 splx(s);
  785                 return (NULL);
  786         }
  787 
  788         n = (struct nd_defrouter *)malloc(sizeof(*n), M_IP6NDP, M_NOWAIT);
  789         if (n == NULL) {
  790                 splx(s);
  791                 return (NULL);
  792         }
  793         bzero(n, sizeof(*n));
  794         *n = *new;
  795 
  796 insert:
  797         /*
  798          * Insert the new router in the Default Router List;
  799          * The Default Router List should be in the descending order
  800          * of router-preferece.  Routers with the same preference are
  801          * sorted in the arriving time order.
  802          */
  803 
  804         /* insert at the end of the group */
  805         for (dr = TAILQ_FIRST(&V_nd_defrouter); dr;
  806              dr = TAILQ_NEXT(dr, dr_entry)) {
  807                 if (rtpref(n) > rtpref(dr))
  808                         break;
  809         }
  810         if (dr)
  811                 TAILQ_INSERT_BEFORE(dr, n, dr_entry);
  812         else
  813                 TAILQ_INSERT_TAIL(&V_nd_defrouter, n, dr_entry);
  814 
  815         defrouter_select();
  816 
  817         splx(s);
  818 
  819         return (n);
  820 }
  821 
  822 static struct nd_pfxrouter *
  823 pfxrtr_lookup(struct nd_prefix *pr, struct nd_defrouter *dr)
  824 {
  825         struct nd_pfxrouter *search;
  826 
  827         for (search = pr->ndpr_advrtrs.lh_first; search; search = search->pfr_next) {
  828                 if (search->router == dr)
  829                         break;
  830         }
  831 
  832         return (search);
  833 }
  834 
  835 static void
  836 pfxrtr_add(struct nd_prefix *pr, struct nd_defrouter *dr)
  837 {
  838         struct nd_pfxrouter *new;
  839 
  840         new = (struct nd_pfxrouter *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  841         if (new == NULL)
  842                 return;
  843         bzero(new, sizeof(*new));
  844         new->router = dr;
  845 
  846         LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
  847 
  848         pfxlist_onlink_check();
  849 }
  850 
  851 static void
  852 pfxrtr_del(struct nd_pfxrouter *pfr)
  853 {
  854         LIST_REMOVE(pfr, pfr_entry);
  855         free(pfr, M_IP6NDP);
  856 }
  857 
  858 struct nd_prefix *
  859 nd6_prefix_lookup(struct nd_prefixctl *key)
  860 {
  861         struct nd_prefix *search;
  862 
  863         for (search = V_nd_prefix.lh_first;
  864             search; search = search->ndpr_next) {
  865                 if (key->ndpr_ifp == search->ndpr_ifp &&
  866                     key->ndpr_plen == search->ndpr_plen &&
  867                     in6_are_prefix_equal(&key->ndpr_prefix.sin6_addr,
  868                     &search->ndpr_prefix.sin6_addr, key->ndpr_plen)) {
  869                         break;
  870                 }
  871         }
  872 
  873         return (search);
  874 }
  875 
  876 int
  877 nd6_prelist_add(struct nd_prefixctl *pr, struct nd_defrouter *dr,
  878     struct nd_prefix **newp)
  879 {
  880         struct nd_prefix *new = NULL;
  881         int error = 0;
  882         int i, s;
  883         char ip6buf[INET6_ADDRSTRLEN];
  884 
  885         new = (struct nd_prefix *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  886         if (new == NULL)
  887                 return(ENOMEM);
  888         bzero(new, sizeof(*new));
  889         new->ndpr_ifp = pr->ndpr_ifp;
  890         new->ndpr_prefix = pr->ndpr_prefix;
  891         new->ndpr_plen = pr->ndpr_plen;
  892         new->ndpr_vltime = pr->ndpr_vltime;
  893         new->ndpr_pltime = pr->ndpr_pltime;
  894         new->ndpr_flags = pr->ndpr_flags;
  895         if ((error = in6_init_prefix_ltimes(new)) != 0) {
  896                 free(new, M_IP6NDP);
  897                 return(error);
  898         }
  899         new->ndpr_lastupdate = time_second;
  900         if (newp != NULL)
  901                 *newp = new;
  902 
  903         /* initialization */
  904         LIST_INIT(&new->ndpr_advrtrs);
  905         in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
  906         /* make prefix in the canonical form */
  907         for (i = 0; i < 4; i++)
  908                 new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
  909                     new->ndpr_mask.s6_addr32[i];
  910 
  911         s = splnet();
  912         /* link ndpr_entry to nd_prefix list */
  913         LIST_INSERT_HEAD(&V_nd_prefix, new, ndpr_entry);
  914         splx(s);
  915 
  916         /* ND_OPT_PI_FLAG_ONLINK processing */
  917         if (new->ndpr_raf_onlink) {
  918                 int e;
  919 
  920                 if ((e = nd6_prefix_onlink(new)) != 0) {
  921                         nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
  922                             "the prefix %s/%d on-link on %s (errno=%d)\n",
  923                             ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
  924                             pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  925                         /* proceed anyway. XXX: is it correct? */
  926                 }
  927         }
  928 
  929         if (dr)
  930                 pfxrtr_add(new, dr);
  931 
  932         return 0;
  933 }
  934 
  935 void
  936 prelist_remove(struct nd_prefix *pr)
  937 {
  938         struct nd_pfxrouter *pfr, *next;
  939         int e, s;
  940         char ip6buf[INET6_ADDRSTRLEN];
  941 
  942         /* make sure to invalidate the prefix until it is really freed. */
  943         pr->ndpr_vltime = 0;
  944         pr->ndpr_pltime = 0;
  945 
  946         /*
  947          * Though these flags are now meaningless, we'd rather keep the value
  948          * of pr->ndpr_raf_onlink and pr->ndpr_raf_auto not to confuse users
  949          * when executing "ndp -p".
  950          */
  951 
  952         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
  953             (e = nd6_prefix_offlink(pr)) != 0) {
  954                 nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
  955                     "on %s, errno=%d\n",
  956                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
  957                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  958                 /* what should we do? */
  959         }
  960 
  961         if (pr->ndpr_refcnt > 0)
  962                 return;         /* notice here? */
  963 
  964         s = splnet();
  965 
  966         /* unlink ndpr_entry from nd_prefix list */
  967         LIST_REMOVE(pr, ndpr_entry);
  968 
  969         /* free list of routers that adversed the prefix */
  970         for (pfr = pr->ndpr_advrtrs.lh_first; pfr; pfr = next) {
  971                 next = pfr->pfr_next;
  972 
  973                 free(pfr, M_IP6NDP);
  974         }
  975         splx(s);
  976 
  977         free(pr, M_IP6NDP);
  978 
  979         pfxlist_onlink_check();
  980 }
  981 
  982 /*
  983  * dr - may be NULL
  984  */
  985 
  986 static int
  987 prelist_update(struct nd_prefixctl *new, struct nd_defrouter *dr,
  988     struct mbuf *m, int mcast)
  989 {
  990         struct in6_ifaddr *ia6 = NULL, *ia6_match = NULL;
  991         struct ifaddr *ifa;
  992         struct ifnet *ifp = new->ndpr_ifp;
  993         struct nd_prefix *pr;
  994         int s = splnet();
  995         int error = 0;
  996         int newprefix = 0;
  997         int auth;
  998         struct in6_addrlifetime lt6_tmp;
  999         char ip6buf[INET6_ADDRSTRLEN];
 1000 
 1001         auth = 0;
 1002         if (m) {
 1003                 /*
 1004                  * Authenticity for NA consists authentication for
 1005                  * both IP header and IP datagrams, doesn't it ?
 1006                  */
 1007 #if defined(M_AUTHIPHDR) && defined(M_AUTHIPDGM)
 1008                 auth = ((m->m_flags & M_AUTHIPHDR) &&
 1009                     (m->m_flags & M_AUTHIPDGM));
 1010 #endif
 1011         }
 1012 
 1013         if ((pr = nd6_prefix_lookup(new)) != NULL) {
 1014                 /*
 1015                  * nd6_prefix_lookup() ensures that pr and new have the same
 1016                  * prefix on a same interface.
 1017                  */
 1018 
 1019                 /*
 1020                  * Update prefix information.  Note that the on-link (L) bit
 1021                  * and the autonomous (A) bit should NOT be changed from 1
 1022                  * to 0.
 1023                  */
 1024                 if (new->ndpr_raf_onlink == 1)
 1025                         pr->ndpr_raf_onlink = 1;
 1026                 if (new->ndpr_raf_auto == 1)
 1027                         pr->ndpr_raf_auto = 1;
 1028                 if (new->ndpr_raf_onlink) {
 1029                         pr->ndpr_vltime = new->ndpr_vltime;
 1030                         pr->ndpr_pltime = new->ndpr_pltime;
 1031                         (void)in6_init_prefix_ltimes(pr); /* XXX error case? */
 1032                         pr->ndpr_lastupdate = time_second;
 1033                 }
 1034 
 1035                 if (new->ndpr_raf_onlink &&
 1036                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1037                         int e;
 1038 
 1039                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1040                                 nd6log((LOG_ERR,
 1041                                     "prelist_update: failed to make "
 1042                                     "the prefix %s/%d on-link on %s "
 1043                                     "(errno=%d)\n",
 1044                                     ip6_sprintf(ip6buf,
 1045                                             &pr->ndpr_prefix.sin6_addr),
 1046                                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
 1047                                 /* proceed anyway. XXX: is it correct? */
 1048                         }
 1049                 }
 1050 
 1051                 if (dr && pfxrtr_lookup(pr, dr) == NULL)
 1052                         pfxrtr_add(pr, dr);
 1053         } else {
 1054                 struct nd_prefix *newpr = NULL;
 1055 
 1056                 newprefix = 1;
 1057 
 1058                 if (new->ndpr_vltime == 0)
 1059                         goto end;
 1060                 if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
 1061                         goto end;
 1062 
 1063                 error = nd6_prelist_add(new, dr, &newpr);
 1064                 if (error != 0 || newpr == NULL) {
 1065                         nd6log((LOG_NOTICE, "prelist_update: "
 1066                             "nd6_prelist_add failed for %s/%d on %s "
 1067                             "errno=%d, returnpr=%p\n",
 1068                             ip6_sprintf(ip6buf, &new->ndpr_prefix.sin6_addr),
 1069                             new->ndpr_plen, if_name(new->ndpr_ifp),
 1070                             error, newpr));
 1071                         goto end; /* we should just give up in this case. */
 1072                 }
 1073 
 1074                 /*
 1075                  * XXX: from the ND point of view, we can ignore a prefix
 1076                  * with the on-link bit being zero.  However, we need a
 1077                  * prefix structure for references from autoconfigured
 1078                  * addresses.  Thus, we explicitly make sure that the prefix
 1079                  * itself expires now.
 1080                  */
 1081                 if (newpr->ndpr_raf_onlink == 0) {
 1082                         newpr->ndpr_vltime = 0;
 1083                         newpr->ndpr_pltime = 0;
 1084                         in6_init_prefix_ltimes(newpr);
 1085                 }
 1086 
 1087                 pr = newpr;
 1088         }
 1089 
 1090         /*
 1091          * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
 1092          * Note that pr must be non NULL at this point.
 1093          */
 1094 
 1095         /* 5.5.3 (a). Ignore the prefix without the A bit set. */
 1096         if (!new->ndpr_raf_auto)
 1097                 goto end;
 1098 
 1099         /*
 1100          * 5.5.3 (b). the link-local prefix should have been ignored in
 1101          * nd6_ra_input.
 1102          */
 1103 
 1104         /* 5.5.3 (c). Consistency check on lifetimes: pltime <= vltime. */
 1105         if (new->ndpr_pltime > new->ndpr_vltime) {
 1106                 error = EINVAL; /* XXX: won't be used */
 1107                 goto end;
 1108         }
 1109 
 1110         /*
 1111          * 5.5.3 (d).  If the prefix advertised is not equal to the prefix of
 1112          * an address configured by stateless autoconfiguration already in the
 1113          * list of addresses associated with the interface, and the Valid
 1114          * Lifetime is not 0, form an address.  We first check if we have
 1115          * a matching prefix.
 1116          * Note: we apply a clarification in rfc2462bis-02 here.  We only
 1117          * consider autoconfigured addresses while RFC2462 simply said
 1118          * "address".
 1119          */
 1120         IF_ADDR_LOCK(ifp);
 1121         TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 1122                 struct in6_ifaddr *ifa6;
 1123                 u_int32_t remaininglifetime;
 1124 
 1125                 if (ifa->ifa_addr->sa_family != AF_INET6)
 1126                         continue;
 1127 
 1128                 ifa6 = (struct in6_ifaddr *)ifa;
 1129 
 1130                 /*
 1131                  * We only consider autoconfigured addresses as per rfc2462bis.
 1132                  */
 1133                 if (!(ifa6->ia6_flags & IN6_IFF_AUTOCONF))
 1134                         continue;
 1135 
 1136                 /*
 1137                  * Spec is not clear here, but I believe we should concentrate
 1138                  * on unicast (i.e. not anycast) addresses.
 1139                  * XXX: other ia6_flags? detached or duplicated?
 1140                  */
 1141                 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0)
 1142                         continue;
 1143 
 1144                 /*
 1145                  * Ignore the address if it is not associated with a prefix
 1146                  * or is associated with a prefix that is different from this
 1147                  * one.  (pr is never NULL here)
 1148                  */
 1149                 if (ifa6->ia6_ndpr != pr)
 1150                         continue;
 1151 
 1152                 if (ia6_match == NULL) /* remember the first one */
 1153                         ia6_match = ifa6;
 1154 
 1155                 /*
 1156                  * An already autoconfigured address matched.  Now that we
 1157                  * are sure there is at least one matched address, we can
 1158                  * proceed to 5.5.3. (e): update the lifetimes according to the
 1159                  * "two hours" rule and the privacy extension.
 1160                  * We apply some clarifications in rfc2462bis:
 1161                  * - use remaininglifetime instead of storedlifetime as a
 1162                  *   variable name
 1163                  * - remove the dead code in the "two-hour" rule
 1164                  */
 1165 #define TWOHOUR         (120*60)
 1166                 lt6_tmp = ifa6->ia6_lifetime;
 1167 
 1168                 if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME)
 1169                         remaininglifetime = ND6_INFINITE_LIFETIME;
 1170                 else if (time_second - ifa6->ia6_updatetime >
 1171                          lt6_tmp.ia6t_vltime) {
 1172                         /*
 1173                          * The case of "invalid" address.  We should usually
 1174                          * not see this case.
 1175                          */
 1176                         remaininglifetime = 0;
 1177                 } else
 1178                         remaininglifetime = lt6_tmp.ia6t_vltime -
 1179                             (time_second - ifa6->ia6_updatetime);
 1180 
 1181                 /* when not updating, keep the current stored lifetime. */
 1182                 lt6_tmp.ia6t_vltime = remaininglifetime;
 1183 
 1184                 if (TWOHOUR < new->ndpr_vltime ||
 1185                     remaininglifetime < new->ndpr_vltime) {
 1186                         lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1187                 } else if (remaininglifetime <= TWOHOUR) {
 1188                         if (auth) {
 1189                                 lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1190                         }
 1191                 } else {
 1192                         /*
 1193                          * new->ndpr_vltime <= TWOHOUR &&
 1194                          * TWOHOUR < remaininglifetime
 1195                          */
 1196                         lt6_tmp.ia6t_vltime = TWOHOUR;
 1197                 }
 1198 
 1199                 /* The 2 hour rule is not imposed for preferred lifetime. */
 1200                 lt6_tmp.ia6t_pltime = new->ndpr_pltime;
 1201 
 1202                 in6_init_address_ltimes(pr, &lt6_tmp);
 1203 
 1204                 /*
 1205                  * We need to treat lifetimes for temporary addresses
 1206                  * differently, according to
 1207                  * draft-ietf-ipv6-privacy-addrs-v2-01.txt 3.3 (1);
 1208                  * we only update the lifetimes when they are in the maximum
 1209                  * intervals.
 1210                  */
 1211                 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0) {
 1212                         u_int32_t maxvltime, maxpltime;
 1213 
 1214                         if (V_ip6_temp_valid_lifetime >
 1215                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1216                             V_ip6_desync_factor)) {
 1217                                 maxvltime = V_ip6_temp_valid_lifetime -
 1218                                     (time_second - ifa6->ia6_createtime) -
 1219                                     V_ip6_desync_factor;
 1220                         } else
 1221                                 maxvltime = 0;
 1222                         if (V_ip6_temp_preferred_lifetime >
 1223                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1224                             V_ip6_desync_factor)) {
 1225                                 maxpltime = V_ip6_temp_preferred_lifetime -
 1226                                     (time_second - ifa6->ia6_createtime) -
 1227                                     V_ip6_desync_factor;
 1228                         } else
 1229                                 maxpltime = 0;
 1230 
 1231                         if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME ||
 1232                             lt6_tmp.ia6t_vltime > maxvltime) {
 1233                                 lt6_tmp.ia6t_vltime = maxvltime;
 1234                         }
 1235                         if (lt6_tmp.ia6t_pltime == ND6_INFINITE_LIFETIME ||
 1236                             lt6_tmp.ia6t_pltime > maxpltime) {
 1237                                 lt6_tmp.ia6t_pltime = maxpltime;
 1238                         }
 1239                 }
 1240                 ifa6->ia6_lifetime = lt6_tmp;
 1241                 ifa6->ia6_updatetime = time_second;
 1242         }
 1243         IF_ADDR_UNLOCK(ifp);
 1244         if (ia6_match == NULL && new->ndpr_vltime) {
 1245                 int ifidlen;
 1246 
 1247                 /*
 1248                  * 5.5.3 (d) (continued)
 1249                  * No address matched and the valid lifetime is non-zero.
 1250                  * Create a new address.
 1251                  */
 1252 
 1253                 /*
 1254                  * Prefix Length check:
 1255                  * If the sum of the prefix length and interface identifier
 1256                  * length does not equal 128 bits, the Prefix Information
 1257                  * option MUST be ignored.  The length of the interface
 1258                  * identifier is defined in a separate link-type specific
 1259                  * document.
 1260                  */
 1261                 ifidlen = in6_if2idlen(ifp);
 1262                 if (ifidlen < 0) {
 1263                         /* this should not happen, so we always log it. */
 1264                         log(LOG_ERR, "prelist_update: IFID undefined (%s)\n",
 1265                             if_name(ifp));
 1266                         goto end;
 1267                 }
 1268                 if (ifidlen + pr->ndpr_plen != 128) {
 1269                         nd6log((LOG_INFO,
 1270                             "prelist_update: invalid prefixlen "
 1271                             "%d for %s, ignored\n",
 1272                             pr->ndpr_plen, if_name(ifp)));
 1273                         goto end;
 1274                 }
 1275 
 1276                 if ((ia6 = in6_ifadd(new, mcast)) != NULL) {
 1277                         /*
 1278                          * note that we should use pr (not new) for reference.
 1279                          */
 1280                         pr->ndpr_refcnt++;
 1281                         ia6->ia6_ndpr = pr;
 1282 
 1283                         /*
 1284                          * RFC 3041 3.3 (2).
 1285                          * When a new public address is created as described
 1286                          * in RFC2462, also create a new temporary address.
 1287                          *
 1288                          * RFC 3041 3.5.
 1289                          * When an interface connects to a new link, a new
 1290                          * randomized interface identifier should be generated
 1291                          * immediately together with a new set of temporary
 1292                          * addresses.  Thus, we specifiy 1 as the 2nd arg of
 1293                          * in6_tmpifadd().
 1294                          */
 1295                         if (V_ip6_use_tempaddr) {
 1296                                 int e;
 1297                                 if ((e = in6_tmpifadd(ia6, 1, 1)) != 0) {
 1298                                         nd6log((LOG_NOTICE, "prelist_update: "
 1299                                             "failed to create a temporary "
 1300                                             "address, errno=%d\n",
 1301                                             e));
 1302                                 }
 1303                         }
 1304                         ifa_free(&ia6->ia_ifa);
 1305 
 1306                         /*
 1307                          * A newly added address might affect the status
 1308                          * of other addresses, so we check and update it.
 1309                          * XXX: what if address duplication happens?
 1310                          */
 1311                         pfxlist_onlink_check();
 1312                 } else {
 1313                         /* just set an error. do not bark here. */
 1314                         error = EADDRNOTAVAIL; /* XXX: might be unused. */
 1315                 }
 1316         }
 1317 
 1318  end:
 1319         splx(s);
 1320         return error;
 1321 }
 1322 
 1323 /*
 1324  * A supplement function used in the on-link detection below;
 1325  * detect if a given prefix has a (probably) reachable advertising router.
 1326  * XXX: lengthy function name...
 1327  */
 1328 static struct nd_pfxrouter *
 1329 find_pfxlist_reachable_router(struct nd_prefix *pr)
 1330 {
 1331         struct nd_pfxrouter *pfxrtr;
 1332         struct llentry *ln;
 1333         int canreach;
 1334 
 1335         for (pfxrtr = LIST_FIRST(&pr->ndpr_advrtrs); pfxrtr != NULL;
 1336              pfxrtr = LIST_NEXT(pfxrtr, pfr_entry)) {
 1337                 IF_AFDATA_LOCK(pfxrtr->router->ifp);
 1338                 ln = nd6_lookup(&pfxrtr->router->rtaddr, 0, pfxrtr->router->ifp);
 1339                 IF_AFDATA_UNLOCK(pfxrtr->router->ifp);
 1340                 if (ln == NULL)
 1341                         continue;
 1342                 canreach = ND6_IS_LLINFO_PROBREACH(ln);
 1343                 LLE_RUNLOCK(ln);
 1344                 if (canreach)
 1345                         break;
 1346         }
 1347         return (pfxrtr);
 1348 }
 1349 
 1350 /*
 1351  * Check if each prefix in the prefix list has at least one available router
 1352  * that advertised the prefix (a router is "available" if its neighbor cache
 1353  * entry is reachable or probably reachable).
 1354  * If the check fails, the prefix may be off-link, because, for example,
 1355  * we have moved from the network but the lifetime of the prefix has not
 1356  * expired yet.  So we should not use the prefix if there is another prefix
 1357  * that has an available router.
 1358  * But, if there is no prefix that has an available router, we still regards
 1359  * all the prefixes as on-link.  This is because we can't tell if all the
 1360  * routers are simply dead or if we really moved from the network and there
 1361  * is no router around us.
 1362  */
 1363 void
 1364 pfxlist_onlink_check()
 1365 {
 1366         struct nd_prefix *pr;
 1367         struct in6_ifaddr *ifa;
 1368         struct nd_defrouter *dr;
 1369         struct nd_pfxrouter *pfxrtr = NULL;
 1370 
 1371         /*
 1372          * Check if there is a prefix that has a reachable advertising
 1373          * router.
 1374          */
 1375         for (pr = V_nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1376                 if (pr->ndpr_raf_onlink && find_pfxlist_reachable_router(pr))
 1377                         break;
 1378         }
 1379 
 1380         /*
 1381          * If we have no such prefix, check whether we still have a router
 1382          * that does not advertise any prefixes.
 1383          */
 1384         if (pr == NULL) {
 1385                 for (dr = TAILQ_FIRST(&V_nd_defrouter); dr;
 1386                     dr = TAILQ_NEXT(dr, dr_entry)) {
 1387                         struct nd_prefix *pr0;
 1388 
 1389                         for (pr0 = V_nd_prefix.lh_first; pr0;
 1390                             pr0 = pr0->ndpr_next) {
 1391                                 if ((pfxrtr = pfxrtr_lookup(pr0, dr)) != NULL)
 1392                                         break;
 1393                         }
 1394                         if (pfxrtr != NULL)
 1395                                 break;
 1396                 }
 1397         }
 1398         if (pr != NULL || (TAILQ_FIRST(&V_nd_defrouter) && pfxrtr == NULL)) {
 1399                 /*
 1400                  * There is at least one prefix that has a reachable router,
 1401                  * or at least a router which probably does not advertise
 1402                  * any prefixes.  The latter would be the case when we move
 1403                  * to a new link where we have a router that does not provide
 1404                  * prefixes and we configure an address by hand.
 1405                  * Detach prefixes which have no reachable advertising
 1406                  * router, and attach other prefixes.
 1407                  */
 1408                 for (pr = V_nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1409                         /* XXX: a link-local prefix should never be detached */
 1410                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1411                                 continue;
 1412 
 1413                         /*
 1414                          * we aren't interested in prefixes without the L bit
 1415                          * set.
 1416                          */
 1417                         if (pr->ndpr_raf_onlink == 0)
 1418                                 continue;
 1419 
 1420                         if (pr->ndpr_raf_auto == 0)
 1421                                 continue;
 1422 
 1423                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1424                             find_pfxlist_reachable_router(pr) == NULL)
 1425                                 pr->ndpr_stateflags |= NDPRF_DETACHED;
 1426                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1427                             find_pfxlist_reachable_router(pr) != 0)
 1428                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1429                 }
 1430         } else {
 1431                 /* there is no prefix that has a reachable router */
 1432                 for (pr = V_nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1433                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1434                                 continue;
 1435 
 1436                         if (pr->ndpr_raf_onlink == 0)
 1437                                 continue;
 1438 
 1439                         if (pr->ndpr_raf_auto == 0)
 1440                                 continue;
 1441 
 1442                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1443                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1444                 }
 1445         }
 1446 
 1447         /*
 1448          * Remove each interface route associated with a (just) detached
 1449          * prefix, and reinstall the interface route for a (just) attached
 1450          * prefix.  Note that all attempt of reinstallation does not
 1451          * necessarily success, when a same prefix is shared among multiple
 1452          * interfaces.  Such cases will be handled in nd6_prefix_onlink,
 1453          * so we don't have to care about them.
 1454          */
 1455         for (pr = V_nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1456                 int e;
 1457                 char ip6buf[INET6_ADDRSTRLEN];
 1458 
 1459                 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1460                         continue;
 1461 
 1462                 if (pr->ndpr_raf_onlink == 0)
 1463                         continue;
 1464 
 1465                 if (pr->ndpr_raf_auto == 0)
 1466                         continue;
 1467 
 1468                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1469                     (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1470                         if ((e = nd6_prefix_offlink(pr)) != 0) {
 1471                                 nd6log((LOG_ERR,
 1472                                     "pfxlist_onlink_check: failed to "
 1473                                     "make %s/%d offlink, errno=%d\n",
 1474                                     ip6_sprintf(ip6buf,
 1475                                             &pr->ndpr_prefix.sin6_addr),
 1476                                             pr->ndpr_plen, e));
 1477                         }
 1478                 }
 1479                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1480                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0 &&
 1481                     pr->ndpr_raf_onlink) {
 1482                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1483                                 nd6log((LOG_ERR,
 1484                                     "pfxlist_onlink_check: failed to "
 1485                                     "make %s/%d onlink, errno=%d\n",
 1486                                     ip6_sprintf(ip6buf,
 1487                                             &pr->ndpr_prefix.sin6_addr),
 1488                                             pr->ndpr_plen, e));
 1489                         }
 1490                 }
 1491         }
 1492 
 1493         /*
 1494          * Changes on the prefix status might affect address status as well.
 1495          * Make sure that all addresses derived from an attached prefix are
 1496          * attached, and that all addresses derived from a detached prefix are
 1497          * detached.  Note, however, that a manually configured address should
 1498          * always be attached.
 1499          * The precise detection logic is same as the one for prefixes.
 1500          *
 1501          * XXXRW: in6_ifaddrhead locking.
 1502          */
 1503         TAILQ_FOREACH(ifa, &V_in6_ifaddrhead, ia_link) {
 1504                 if (!(ifa->ia6_flags & IN6_IFF_AUTOCONF))
 1505                         continue;
 1506 
 1507                 if (ifa->ia6_ndpr == NULL) {
 1508                         /*
 1509                          * This can happen when we first configure the address
 1510                          * (i.e. the address exists, but the prefix does not).
 1511                          * XXX: complicated relationships...
 1512                          */
 1513                         continue;
 1514                 }
 1515 
 1516                 if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
 1517                         break;
 1518         }
 1519         if (ifa) {
 1520                 TAILQ_FOREACH(ifa, &V_in6_ifaddrhead, ia_link) {
 1521                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1522                                 continue;
 1523 
 1524                         if (ifa->ia6_ndpr == NULL) /* XXX: see above. */
 1525                                 continue;
 1526 
 1527                         if (find_pfxlist_reachable_router(ifa->ia6_ndpr)) {
 1528                                 if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1529                                         ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1530                                         ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1531                                         nd6_dad_start((struct ifaddr *)ifa, 0);
 1532                                 }
 1533                         } else {
 1534                                 ifa->ia6_flags |= IN6_IFF_DETACHED;
 1535                         }
 1536                 }
 1537         }
 1538         else {
 1539                 TAILQ_FOREACH(ifa, &V_in6_ifaddrhead, ia_link) {
 1540                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1541                                 continue;
 1542 
 1543                         if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1544                                 ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1545                                 ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1546                                 /* Do we need a delay in this case? */
 1547                                 nd6_dad_start((struct ifaddr *)ifa, 0);
 1548                         }
 1549                 }
 1550         }
 1551 }
 1552 
 1553 int
 1554 nd6_prefix_onlink(struct nd_prefix *pr)
 1555 {
 1556         struct ifaddr *ifa;
 1557         struct ifnet *ifp = pr->ndpr_ifp;
 1558         struct sockaddr_in6 mask6;
 1559         struct nd_prefix *opr;
 1560         u_long rtflags;
 1561         int error = 0;
 1562         struct radix_node_head *rnh;
 1563         struct rtentry *rt = NULL;
 1564         char ip6buf[INET6_ADDRSTRLEN];
 1565         struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
 1566 
 1567         /* sanity check */
 1568         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1569                 nd6log((LOG_ERR,
 1570                     "nd6_prefix_onlink: %s/%d is already on-link\n",
 1571                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1572                     pr->ndpr_plen));
 1573                 return (EEXIST);
 1574         }
 1575 
 1576         /*
 1577          * Add the interface route associated with the prefix.  Before
 1578          * installing the route, check if there's the same prefix on another
 1579          * interface, and the prefix has already installed the interface route.
 1580          * Although such a configuration is expected to be rare, we explicitly
 1581          * allow it.
 1582          */
 1583         for (opr = V_nd_prefix.lh_first; opr; opr = opr->ndpr_next) {
 1584                 if (opr == pr)
 1585                         continue;
 1586 
 1587                 if ((opr->ndpr_stateflags & NDPRF_ONLINK) == 0)
 1588                         continue;
 1589 
 1590                 if (opr->ndpr_plen == pr->ndpr_plen &&
 1591                     in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1592                     &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen))
 1593                         return (0);
 1594         }
 1595 
 1596         /*
 1597          * We prefer link-local addresses as the associated interface address.
 1598          */
 1599         /* search for a link-local addr */
 1600         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
 1601             IN6_IFF_NOTREADY | IN6_IFF_ANYCAST);
 1602         if (ifa == NULL) {
 1603                 /* XXX: freebsd does not have ifa_ifwithaf */
 1604                 IF_ADDR_LOCK(ifp);
 1605                 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 1606                         if (ifa->ifa_addr->sa_family == AF_INET6)
 1607                                 break;
 1608                 }
 1609                 if (ifa != NULL)
 1610                         ifa_ref(ifa);
 1611                 IF_ADDR_UNLOCK(ifp);
 1612                 /* should we care about ia6_flags? */
 1613         }
 1614         if (ifa == NULL) {
 1615                 /*
 1616                  * This can still happen, when, for example, we receive an RA
 1617                  * containing a prefix with the L bit set and the A bit clear,
 1618                  * after removing all IPv6 addresses on the receiving
 1619                  * interface.  This should, of course, be rare though.
 1620                  */
 1621                 nd6log((LOG_NOTICE,
 1622                     "nd6_prefix_onlink: failed to find any ifaddr"
 1623                     " to add route for a prefix(%s/%d) on %s\n",
 1624                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1625                     pr->ndpr_plen, if_name(ifp)));
 1626                 return (0);
 1627         }
 1628 
 1629         /*
 1630          * in6_ifinit() sets nd6_rtrequest to ifa_rtrequest for all ifaddrs.
 1631          * ifa->ifa_rtrequest = nd6_rtrequest;
 1632          */
 1633         bzero(&mask6, sizeof(mask6));
 1634         mask6.sin6_len = sizeof(mask6);
 1635         mask6.sin6_addr = pr->ndpr_mask;
 1636         rtflags = (ifa->ifa_flags & ~IFA_RTSELF) | RTF_UP;
 1637         error = rtrequest(RTM_ADD, (struct sockaddr *)&pr->ndpr_prefix,
 1638             ifa->ifa_addr, (struct sockaddr *)&mask6, rtflags, &rt);
 1639         if (error == 0) {
 1640                 if (rt != NULL) /* this should be non NULL, though */ {
 1641                         rnh = rt_tables_get_rnh(rt->rt_fibnum, AF_INET6);
 1642                         /* XXX what if rhn == NULL? */
 1643                         RADIX_NODE_HEAD_LOCK(rnh);
 1644                         RT_LOCK(rt);
 1645                         if (!rt_setgate(rt, rt_key(rt), (struct sockaddr *)&null_sdl)) {
 1646                                 ((struct sockaddr_dl *)rt->rt_gateway)->sdl_type =
 1647                                         rt->rt_ifp->if_type;
 1648                                 ((struct sockaddr_dl *)rt->rt_gateway)->sdl_index =
 1649                                         rt->rt_ifp->if_index;
 1650                         }
 1651                         RADIX_NODE_HEAD_UNLOCK(rnh);
 1652                         nd6_rtmsg(RTM_ADD, rt);
 1653                         RT_UNLOCK(rt);
 1654                 }
 1655                 pr->ndpr_stateflags |= NDPRF_ONLINK;
 1656         } else {
 1657                 char ip6bufg[INET6_ADDRSTRLEN], ip6bufm[INET6_ADDRSTRLEN];
 1658                 nd6log((LOG_ERR, "nd6_prefix_onlink: failed to add route for a"
 1659                     " prefix (%s/%d) on %s, gw=%s, mask=%s, flags=%lx "
 1660                     "errno = %d\n",
 1661                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1662                     pr->ndpr_plen, if_name(ifp),
 1663                     ip6_sprintf(ip6bufg, &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr),
 1664                     ip6_sprintf(ip6bufm, &mask6.sin6_addr), rtflags, error));
 1665         }
 1666 
 1667         if (rt != NULL) {
 1668                 RT_LOCK(rt);
 1669                 RT_REMREF(rt);
 1670                 RT_UNLOCK(rt);
 1671         }
 1672         if (ifa != NULL)
 1673                 ifa_free(ifa);
 1674 
 1675         return (error);
 1676 }
 1677 
 1678 int
 1679 nd6_prefix_offlink(struct nd_prefix *pr)
 1680 {
 1681         int error = 0;
 1682         struct ifnet *ifp = pr->ndpr_ifp;
 1683         struct nd_prefix *opr;
 1684         struct sockaddr_in6 sa6, mask6;
 1685         struct rtentry *rt = NULL;
 1686         char ip6buf[INET6_ADDRSTRLEN];
 1687 
 1688         /* sanity check */
 1689         if ((pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1690                 nd6log((LOG_ERR,
 1691                     "nd6_prefix_offlink: %s/%d is already off-link\n",
 1692                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1693                     pr->ndpr_plen));
 1694                 return (EEXIST);
 1695         }
 1696 
 1697         bzero(&sa6, sizeof(sa6));
 1698         sa6.sin6_family = AF_INET6;
 1699         sa6.sin6_len = sizeof(sa6);
 1700         bcopy(&pr->ndpr_prefix.sin6_addr, &sa6.sin6_addr,
 1701             sizeof(struct in6_addr));
 1702         bzero(&mask6, sizeof(mask6));
 1703         mask6.sin6_family = AF_INET6;
 1704         mask6.sin6_len = sizeof(sa6);
 1705         bcopy(&pr->ndpr_mask, &mask6.sin6_addr, sizeof(struct in6_addr));
 1706         error = rtrequest(RTM_DELETE, (struct sockaddr *)&sa6, NULL,
 1707             (struct sockaddr *)&mask6, 0, &rt);
 1708         if (error == 0) {
 1709                 pr->ndpr_stateflags &= ~NDPRF_ONLINK;
 1710 
 1711                 /* report the route deletion to the routing socket. */
 1712                 if (rt != NULL)
 1713                         nd6_rtmsg(RTM_DELETE, rt);
 1714 
 1715                 /*
 1716                  * There might be the same prefix on another interface,
 1717                  * the prefix which could not be on-link just because we have
 1718                  * the interface route (see comments in nd6_prefix_onlink).
 1719                  * If there's one, try to make the prefix on-link on the
 1720                  * interface.
 1721                  */
 1722                 for (opr = V_nd_prefix.lh_first; opr; opr = opr->ndpr_next) {
 1723                         if (opr == pr)
 1724                                 continue;
 1725 
 1726                         if ((opr->ndpr_stateflags & NDPRF_ONLINK) != 0)
 1727                                 continue;
 1728 
 1729                         /*
 1730                          * KAME specific: detached prefixes should not be
 1731                          * on-link.
 1732                          */
 1733                         if ((opr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1734                                 continue;
 1735 
 1736                         if (opr->ndpr_plen == pr->ndpr_plen &&
 1737                             in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1738                             &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
 1739                                 int e;
 1740 
 1741                                 if ((e = nd6_prefix_onlink(opr)) != 0) {
 1742                                         nd6log((LOG_ERR,
 1743                                             "nd6_prefix_offlink: failed to "
 1744                                             "recover a prefix %s/%d from %s "
 1745                                             "to %s (errno = %d)\n",
 1746                                             ip6_sprintf(ip6buf,
 1747                                                 &opr->ndpr_prefix.sin6_addr),
 1748                                             opr->ndpr_plen, if_name(ifp),
 1749                                             if_name(opr->ndpr_ifp), e));
 1750                                 }
 1751                         }
 1752                 }
 1753         } else {
 1754                 /* XXX: can we still set the NDPRF_ONLINK flag? */
 1755                 nd6log((LOG_ERR,
 1756                     "nd6_prefix_offlink: failed to delete route: "
 1757                     "%s/%d on %s (errno = %d)\n",
 1758                     ip6_sprintf(ip6buf, &sa6.sin6_addr), pr->ndpr_plen,
 1759                     if_name(ifp), error));
 1760         }
 1761 
 1762         if (rt != NULL) {
 1763                 RTFREE(rt);
 1764         }
 1765 
 1766         return (error);
 1767 }
 1768 
 1769 static struct in6_ifaddr *
 1770 in6_ifadd(struct nd_prefixctl *pr, int mcast)
 1771 {
 1772         struct ifnet *ifp = pr->ndpr_ifp;
 1773         struct ifaddr *ifa;
 1774         struct in6_aliasreq ifra;
 1775         struct in6_ifaddr *ia, *ib;
 1776         int error, plen0;
 1777         struct in6_addr mask;
 1778         int prefixlen = pr->ndpr_plen;
 1779         int updateflags;
 1780         char ip6buf[INET6_ADDRSTRLEN];
 1781 
 1782         in6_prefixlen2mask(&mask, prefixlen);
 1783 
 1784         /*
 1785          * find a link-local address (will be interface ID).
 1786          * Is it really mandatory? Theoretically, a global or a site-local
 1787          * address can be configured without a link-local address, if we
 1788          * have a unique interface identifier...
 1789          *
 1790          * it is not mandatory to have a link-local address, we can generate
 1791          * interface identifier on the fly.  we do this because:
 1792          * (1) it should be the easiest way to find interface identifier.
 1793          * (2) RFC2462 5.4 suggesting the use of the same interface identifier
 1794          * for multiple addresses on a single interface, and possible shortcut
 1795          * of DAD.  we omitted DAD for this reason in the past.
 1796          * (3) a user can prevent autoconfiguration of global address
 1797          * by removing link-local address by hand (this is partly because we
 1798          * don't have other way to control the use of IPv6 on an interface.
 1799          * this has been our design choice - cf. NRL's "ifconfig auto").
 1800          * (4) it is easier to manage when an interface has addresses
 1801          * with the same interface identifier, than to have multiple addresses
 1802          * with different interface identifiers.
 1803          */
 1804         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0); /* 0 is OK? */
 1805         if (ifa)
 1806                 ib = (struct in6_ifaddr *)ifa;
 1807         else
 1808                 return NULL;
 1809 
 1810         /* prefixlen + ifidlen must be equal to 128 */
 1811         plen0 = in6_mask2len(&ib->ia_prefixmask.sin6_addr, NULL);
 1812         if (prefixlen != plen0) {
 1813                 ifa_free(ifa);
 1814                 nd6log((LOG_INFO, "in6_ifadd: wrong prefixlen for %s "
 1815                     "(prefix=%d ifid=%d)\n",
 1816                     if_name(ifp), prefixlen, 128 - plen0));
 1817                 return NULL;
 1818         }
 1819 
 1820         /* make ifaddr */
 1821 
 1822         bzero(&ifra, sizeof(ifra));
 1823         /*
 1824          * in6_update_ifa() does not use ifra_name, but we accurately set it
 1825          * for safety.
 1826          */
 1827         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1828         ifra.ifra_addr.sin6_family = AF_INET6;
 1829         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
 1830         /* prefix */
 1831         ifra.ifra_addr.sin6_addr = pr->ndpr_prefix.sin6_addr;
 1832         ifra.ifra_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
 1833         ifra.ifra_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
 1834         ifra.ifra_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
 1835         ifra.ifra_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
 1836 
 1837         /* interface ID */
 1838         ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
 1839             (ib->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
 1840         ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
 1841             (ib->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
 1842         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1843             (ib->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
 1844         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1845             (ib->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);
 1846         ifa_free(ifa);
 1847 
 1848         /* new prefix mask. */
 1849         ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
 1850         ifra.ifra_prefixmask.sin6_family = AF_INET6;
 1851         bcopy(&mask, &ifra.ifra_prefixmask.sin6_addr,
 1852             sizeof(ifra.ifra_prefixmask.sin6_addr));
 1853 
 1854         /* lifetimes. */
 1855         ifra.ifra_lifetime.ia6t_vltime = pr->ndpr_vltime;
 1856         ifra.ifra_lifetime.ia6t_pltime = pr->ndpr_pltime;
 1857 
 1858         /* XXX: scope zone ID? */
 1859 
 1860         ifra.ifra_flags |= IN6_IFF_AUTOCONF; /* obey autoconf */
 1861 
 1862         /*
 1863          * Make sure that we do not have this address already.  This should
 1864          * usually not happen, but we can still see this case, e.g., if we
 1865          * have manually configured the exact address to be configured.
 1866          */
 1867         ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp,
 1868             &ifra.ifra_addr.sin6_addr);
 1869         if (ifa != NULL) {
 1870                 ifa_free(ifa);
 1871                 /* this should be rare enough to make an explicit log */
 1872                 log(LOG_INFO, "in6_ifadd: %s is already configured\n",
 1873                     ip6_sprintf(ip6buf, &ifra.ifra_addr.sin6_addr));
 1874                 return (NULL);
 1875         }
 1876 
 1877         /*
 1878          * Allocate ifaddr structure, link into chain, etc.
 1879          * If we are going to create a new address upon receiving a multicasted
 1880          * RA, we need to impose a random delay before starting DAD.
 1881          * [draft-ietf-ipv6-rfc2462bis-02.txt, Section 5.4.2]
 1882          */
 1883         updateflags = 0;
 1884         if (mcast)
 1885                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1886         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0) {
 1887                 nd6log((LOG_ERR,
 1888                     "in6_ifadd: failed to make ifaddr %s on %s (errno=%d)\n",
 1889                     ip6_sprintf(ip6buf, &ifra.ifra_addr.sin6_addr),
 1890                     if_name(ifp), error));
 1891                 return (NULL);  /* ifaddr must not have been allocated. */
 1892         }
 1893 
 1894         ia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1895         /*
 1896          * XXXRW: Assumption of non-NULLness here might not be true with
 1897          * fine-grained locking -- should we validate it?  Or just return
 1898          * earlier ifa rather than looking it up again?
 1899          */
 1900         return (ia);            /* this is always non-NULL  and referenced. */
 1901 }
 1902 
 1903 /*
 1904  * ia0 - corresponding public address
 1905  */
 1906 int
 1907 in6_tmpifadd(const struct in6_ifaddr *ia0, int forcegen, int delay)
 1908 {
 1909         struct ifnet *ifp = ia0->ia_ifa.ifa_ifp;
 1910         struct in6_ifaddr *newia, *ia;
 1911         struct in6_aliasreq ifra;
 1912         int i, error;
 1913         int trylimit = 3;       /* XXX: adhoc value */
 1914         int updateflags;
 1915         u_int32_t randid[2];
 1916         time_t vltime0, pltime0;
 1917 
 1918         bzero(&ifra, sizeof(ifra));
 1919         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1920         ifra.ifra_addr = ia0->ia_addr;
 1921         /* copy prefix mask */
 1922         ifra.ifra_prefixmask = ia0->ia_prefixmask;
 1923         /* clear the old IFID */
 1924         for (i = 0; i < 4; i++) {
 1925                 ifra.ifra_addr.sin6_addr.s6_addr32[i] &=
 1926                     ifra.ifra_prefixmask.sin6_addr.s6_addr32[i];
 1927         }
 1928 
 1929   again:
 1930         if (in6_get_tmpifid(ifp, (u_int8_t *)randid,
 1931             (const u_int8_t *)&ia0->ia_addr.sin6_addr.s6_addr[8], forcegen)) {
 1932                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to find a good "
 1933                     "random IFID\n"));
 1934                 return (EINVAL);
 1935         }
 1936         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1937             (randid[0] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[2]));
 1938         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1939             (randid[1] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[3]));
 1940 
 1941         /*
 1942          * in6_get_tmpifid() quite likely provided a unique interface ID.
 1943          * However, we may still have a chance to see collision, because
 1944          * there may be a time lag between generation of the ID and generation
 1945          * of the address.  So, we'll do one more sanity check.
 1946          */
 1947         IN6_IFADDR_RLOCK();
 1948         TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) {
 1949                 if (IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
 1950                     &ifra.ifra_addr.sin6_addr)) {
 1951                         if (trylimit-- == 0) {
 1952                                 IN6_IFADDR_RUNLOCK();
 1953                                 /*
 1954                                  * Give up.  Something strange should have
 1955                                  * happened.
 1956                                  */
 1957                                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to "
 1958                                     "find a unique random IFID\n"));
 1959                                 return (EEXIST);
 1960                         }
 1961                         IN6_IFADDR_RUNLOCK();
 1962                         forcegen = 1;
 1963                         goto again;
 1964                 }
 1965         }
 1966         IN6_IFADDR_RUNLOCK();
 1967 
 1968         /*
 1969          * The Valid Lifetime is the lower of the Valid Lifetime of the
 1970          * public address or TEMP_VALID_LIFETIME.
 1971          * The Preferred Lifetime is the lower of the Preferred Lifetime
 1972          * of the public address or TEMP_PREFERRED_LIFETIME -
 1973          * DESYNC_FACTOR.
 1974          */
 1975         if (ia0->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
 1976                 vltime0 = IFA6_IS_INVALID(ia0) ? 0 :
 1977                     (ia0->ia6_lifetime.ia6t_vltime -
 1978                     (time_second - ia0->ia6_updatetime));
 1979                 if (vltime0 > V_ip6_temp_valid_lifetime)
 1980                         vltime0 = V_ip6_temp_valid_lifetime;
 1981         } else
 1982                 vltime0 = V_ip6_temp_valid_lifetime;
 1983         if (ia0->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
 1984                 pltime0 = IFA6_IS_DEPRECATED(ia0) ? 0 :
 1985                     (ia0->ia6_lifetime.ia6t_pltime -
 1986                     (time_second - ia0->ia6_updatetime));
 1987                 if (pltime0 > V_ip6_temp_preferred_lifetime - V_ip6_desync_factor){
 1988                         pltime0 = V_ip6_temp_preferred_lifetime -
 1989                             V_ip6_desync_factor;
 1990                 }
 1991         } else
 1992                 pltime0 = V_ip6_temp_preferred_lifetime - V_ip6_desync_factor;
 1993         ifra.ifra_lifetime.ia6t_vltime = vltime0;
 1994         ifra.ifra_lifetime.ia6t_pltime = pltime0;
 1995 
 1996         /*
 1997          * A temporary address is created only if this calculated Preferred
 1998          * Lifetime is greater than REGEN_ADVANCE time units.
 1999          */
 2000         if (ifra.ifra_lifetime.ia6t_pltime <= V_ip6_temp_regen_advance)
 2001                 return (0);
 2002 
 2003         /* XXX: scope zone ID? */
 2004 
 2005         ifra.ifra_flags |= (IN6_IFF_AUTOCONF|IN6_IFF_TEMPORARY);
 2006 
 2007         /* allocate ifaddr structure, link into chain, etc. */
 2008         updateflags = 0;
 2009         if (delay)
 2010                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 2011         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0)
 2012                 return (error);
 2013 
 2014         newia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 2015         if (newia == NULL) {    /* XXX: can it happen? */
 2016                 nd6log((LOG_ERR,
 2017                     "in6_tmpifadd: ifa update succeeded, but we got "
 2018                     "no ifaddr\n"));
 2019                 return (EINVAL); /* XXX */
 2020         }
 2021         newia->ia6_ndpr = ia0->ia6_ndpr;
 2022         newia->ia6_ndpr->ndpr_refcnt++;
 2023         ifa_free(&newia->ia_ifa);
 2024 
 2025         /*
 2026          * A newly added address might affect the status of other addresses.
 2027          * XXX: when the temporary address is generated with a new public
 2028          * address, the onlink check is redundant.  However, it would be safe
 2029          * to do the check explicitly everywhere a new address is generated,
 2030          * and, in fact, we surely need the check when we create a new
 2031          * temporary address due to deprecation of an old temporary address.
 2032          */
 2033         pfxlist_onlink_check();
 2034 
 2035         return (0);
 2036 }
 2037 
 2038 static int
 2039 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
 2040 {
 2041         if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
 2042                 ndpr->ndpr_preferred = 0;
 2043         else
 2044                 ndpr->ndpr_preferred = time_second + ndpr->ndpr_pltime;
 2045         if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
 2046                 ndpr->ndpr_expire = 0;
 2047         else
 2048                 ndpr->ndpr_expire = time_second + ndpr->ndpr_vltime;
 2049 
 2050         return 0;
 2051 }
 2052 
 2053 static void
 2054 in6_init_address_ltimes(struct nd_prefix *new, struct in6_addrlifetime *lt6)
 2055 {
 2056         /* init ia6t_expire */
 2057         if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
 2058                 lt6->ia6t_expire = 0;
 2059         else {
 2060                 lt6->ia6t_expire = time_second;
 2061                 lt6->ia6t_expire += lt6->ia6t_vltime;
 2062         }
 2063 
 2064         /* init ia6t_preferred */
 2065         if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
 2066                 lt6->ia6t_preferred = 0;
 2067         else {
 2068                 lt6->ia6t_preferred = time_second;
 2069                 lt6->ia6t_preferred += lt6->ia6t_pltime;
 2070         }
 2071 }
 2072 
 2073 /*
 2074  * Delete all the routing table entries that use the specified gateway.
 2075  * XXX: this function causes search through all entries of routing table, so
 2076  * it shouldn't be called when acting as a router.
 2077  */
 2078 void
 2079 rt6_flush(struct in6_addr *gateway, struct ifnet *ifp)
 2080 {
 2081         struct radix_node_head *rnh;
 2082         int s = splnet();
 2083 
 2084         /* We'll care only link-local addresses */
 2085         if (!IN6_IS_ADDR_LINKLOCAL(gateway)) {
 2086                 splx(s);
 2087                 return;
 2088         }
 2089 
 2090         rnh = rt_tables_get_rnh(0, AF_INET6);
 2091         if (rnh == NULL)
 2092                 return;
 2093 
 2094         RADIX_NODE_HEAD_LOCK(rnh);
 2095         rnh->rnh_walktree(rnh, rt6_deleteroute, (void *)gateway);
 2096         RADIX_NODE_HEAD_UNLOCK(rnh);
 2097         splx(s);
 2098 }
 2099 
 2100 static int
 2101 rt6_deleteroute(struct radix_node *rn, void *arg)
 2102 {
 2103 #define SIN6(s) ((struct sockaddr_in6 *)s)
 2104         struct rtentry *rt = (struct rtentry *)rn;
 2105         struct in6_addr *gate = (struct in6_addr *)arg;
 2106 
 2107         if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
 2108                 return (0);
 2109 
 2110         if (!IN6_ARE_ADDR_EQUAL(gate, &SIN6(rt->rt_gateway)->sin6_addr)) {
 2111                 return (0);
 2112         }
 2113 
 2114         /*
 2115          * Do not delete a static route.
 2116          * XXX: this seems to be a bit ad-hoc. Should we consider the
 2117          * 'cloned' bit instead?
 2118          */
 2119         if ((rt->rt_flags & RTF_STATIC) != 0)
 2120                 return (0);
 2121 
 2122         /*
 2123          * We delete only host route. This means, in particular, we don't
 2124          * delete default route.
 2125          */
 2126         if ((rt->rt_flags & RTF_HOST) == 0)
 2127                 return (0);
 2128 
 2129         return (rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
 2130             rt_mask(rt), rt->rt_flags, 0));
 2131 #undef SIN6
 2132 }
 2133 
 2134 int
 2135 nd6_setdefaultiface(int ifindex)
 2136 {
 2137         int error = 0;
 2138 
 2139         if (ifindex < 0 || V_if_index < ifindex)
 2140                 return (EINVAL);
 2141         if (ifindex != 0 && !ifnet_byindex(ifindex))
 2142                 return (EINVAL);
 2143 
 2144         if (V_nd6_defifindex != ifindex) {
 2145                 V_nd6_defifindex = ifindex;
 2146                 if (V_nd6_defifindex > 0)
 2147                         V_nd6_defifp = ifnet_byindex(V_nd6_defifindex);
 2148                 else
 2149                         V_nd6_defifp = NULL;
 2150 
 2151                 /*
 2152                  * Our current implementation assumes one-to-one maping between
 2153                  * interfaces and links, so it would be natural to use the
 2154                  * default interface as the default link.
 2155                  */
 2156                 scope6_setdefault(V_nd6_defifp);
 2157         }
 2158 
 2159         return (error);
 2160 }

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