The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: 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: stable/7/sys/netinet6/nd6_rtr.c 231686 2012-02-14 15:18:08Z 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/errno.h>
   47 #include <sys/syslog.h>
   48 #include <sys/queue.h>
   49 
   50 #include <net/if.h>
   51 #include <net/if_types.h>
   52 #include <net/if_dl.h>
   53 #include <net/route.h>
   54 #include <net/radix.h>
   55 
   56 #include <netinet/in.h>
   57 #include <netinet6/in6_var.h>
   58 #include <netinet6/in6_ifattach.h>
   59 #include <netinet/ip6.h>
   60 #include <netinet6/ip6_var.h>
   61 #include <netinet6/nd6.h>
   62 #include <netinet/icmp6.h>
   63 #include <netinet6/scope6_var.h>
   64 
   65 #define SDL(s)  ((struct sockaddr_dl *)s)
   66 
   67 static int rtpref(struct nd_defrouter *);
   68 static struct nd_defrouter *defrtrlist_update(struct nd_defrouter *);
   69 static int prelist_update __P((struct nd_prefixctl *, struct nd_defrouter *,
   70     struct mbuf *, int));
   71 static struct in6_ifaddr *in6_ifadd(struct nd_prefixctl *,      int);
   72 static struct nd_pfxrouter *pfxrtr_lookup __P((struct nd_prefix *,
   73         struct nd_defrouter *));
   74 static void pfxrtr_add(struct nd_prefix *, struct nd_defrouter *);
   75 static void pfxrtr_del(struct nd_pfxrouter *);
   76 static struct nd_pfxrouter *find_pfxlist_reachable_router
   77 (struct nd_prefix *);
   78 static void defrouter_delreq(struct nd_defrouter *);
   79 static void nd6_rtmsg(int, struct rtentry *);
   80 
   81 static int in6_init_prefix_ltimes(struct nd_prefix *);
   82 static void in6_init_address_ltimes __P((struct nd_prefix *,
   83         struct in6_addrlifetime *));
   84 
   85 static int nd6_prefix_onlink(struct nd_prefix *);
   86 static int nd6_prefix_offlink(struct nd_prefix *);
   87 
   88 static int rt6_deleteroute(struct radix_node *, void *);
   89 
   90 extern int nd6_recalc_reachtm_interval;
   91 
   92 static struct ifnet *nd6_defifp;
   93 int nd6_defifindex;
   94 
   95 int ip6_use_tempaddr = 0;
   96 
   97 int ip6_desync_factor;
   98 u_int32_t ip6_temp_preferred_lifetime = DEF_TEMP_PREFERRED_LIFETIME;
   99 u_int32_t ip6_temp_valid_lifetime = DEF_TEMP_VALID_LIFETIME;
  100 /*
  101  * shorter lifetimes for debugging purposes.
  102 int ip6_temp_preferred_lifetime = 800;
  103 static int ip6_temp_valid_lifetime = 1800;
  104 */
  105 int ip6_temp_regen_advance = TEMPADDR_REGEN_ADVANCE;
  106 
  107 /* RTPREF_MEDIUM has to be 0! */
  108 #define RTPREF_HIGH     1
  109 #define RTPREF_MEDIUM   0
  110 #define RTPREF_LOW      (-1)
  111 #define RTPREF_RESERVED (-2)
  112 #define RTPREF_INVALID  (-3)    /* internal */
  113 
  114 /*
  115  * Receive Router Solicitation Message - just for routers.
  116  * Router solicitation/advertisement is mostly managed by userland program
  117  * (rtadvd) so here we have no function like nd6_ra_output().
  118  *
  119  * Based on RFC 2461
  120  */
  121 void
  122 nd6_rs_input(struct mbuf *m, int off, int icmp6len)
  123 {
  124         struct ifnet *ifp = m->m_pkthdr.rcvif;
  125         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  126         struct nd_router_solicit *nd_rs;
  127         struct in6_addr saddr6 = ip6->ip6_src;
  128         char *lladdr = NULL;
  129         int lladdrlen = 0;
  130         union nd_opts ndopts;
  131         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  132 
  133         /* If I'm not a router, ignore it. */
  134         if (ip6_accept_rtadv != 0 || ip6_forwarding != 1)
  135                 goto freeit;
  136 
  137         /* Sanity checks */
  138         if (ip6->ip6_hlim != 255) {
  139                 nd6log((LOG_ERR,
  140                     "nd6_rs_input: invalid hlim (%d) from %s to %s on %s\n",
  141                     ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  142                     ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
  143                 goto bad;
  144         }
  145 
  146         /*
  147          * Don't update the neighbor cache, if src = ::.
  148          * This indicates that the src has no IP address assigned yet.
  149          */
  150         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  151                 goto freeit;
  152 
  153 #ifndef PULLDOWN_TEST
  154         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  155         nd_rs = (struct nd_router_solicit *)((caddr_t)ip6 + off);
  156 #else
  157         IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
  158         if (nd_rs == NULL) {
  159                 icmp6stat.icp6s_tooshort++;
  160                 return;
  161         }
  162 #endif
  163 
  164         icmp6len -= sizeof(*nd_rs);
  165         nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
  166         if (nd6_options(&ndopts) < 0) {
  167                 nd6log((LOG_INFO,
  168                     "nd6_rs_input: invalid ND option, ignored\n"));
  169                 /* nd6_options have incremented stats */
  170                 goto freeit;
  171         }
  172 
  173         if (ndopts.nd_opts_src_lladdr) {
  174                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  175                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  176         }
  177 
  178         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  179                 nd6log((LOG_INFO,
  180                     "nd6_rs_input: lladdrlen mismatch for %s "
  181                     "(if %d, RS packet %d)\n",
  182                     ip6_sprintf(ip6bufs, &saddr6),
  183                     ifp->if_addrlen, lladdrlen - 2));
  184                 goto bad;
  185         }
  186 
  187         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
  188 
  189  freeit:
  190         m_freem(m);
  191         return;
  192 
  193  bad:
  194         icmp6stat.icp6s_badrs++;
  195         m_freem(m);
  196 }
  197 
  198 /*
  199  * Receive Router Advertisement Message.
  200  *
  201  * Based on RFC 2461
  202  * TODO: on-link bit on prefix information
  203  * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
  204  */
  205 void
  206 nd6_ra_input(struct mbuf *m, int off, int icmp6len)
  207 {
  208         struct ifnet *ifp = m->m_pkthdr.rcvif;
  209         struct nd_ifinfo *ndi = ND_IFINFO(ifp);
  210         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  211         struct nd_router_advert *nd_ra;
  212         struct in6_addr saddr6 = ip6->ip6_src;
  213         int mcast = 0;
  214         union nd_opts ndopts;
  215         struct nd_defrouter *dr;
  216         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  217 
  218         /*
  219          * We only accept RAs only when
  220          * the system-wide variable allows the acceptance, and
  221          * per-interface variable allows RAs on the receiving interface.
  222          */
  223         if (ip6_accept_rtadv == 0)
  224                 goto freeit;
  225         if (!(ndi->flags & ND6_IFF_ACCEPT_RTADV))
  226                 goto freeit;
  227 
  228         if (ip6->ip6_hlim != 255) {
  229                 nd6log((LOG_ERR,
  230                     "nd6_ra_input: invalid hlim (%d) from %s to %s on %s\n",
  231                     ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  232                     ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
  233                 goto bad;
  234         }
  235 
  236         if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
  237                 nd6log((LOG_ERR,
  238                     "nd6_ra_input: src %s is not link-local\n",
  239                     ip6_sprintf(ip6bufs, &saddr6)));
  240                 goto bad;
  241         }
  242 
  243 #ifndef PULLDOWN_TEST
  244         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  245         nd_ra = (struct nd_router_advert *)((caddr_t)ip6 + off);
  246 #else
  247         IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
  248         if (nd_ra == NULL) {
  249                 icmp6stat.icp6s_tooshort++;
  250                 return;
  251         }
  252 #endif
  253 
  254         icmp6len -= sizeof(*nd_ra);
  255         nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
  256         if (nd6_options(&ndopts) < 0) {
  257                 nd6log((LOG_INFO,
  258                     "nd6_ra_input: invalid ND option, ignored\n"));
  259                 /* nd6_options have incremented stats */
  260                 goto freeit;
  261         }
  262 
  263     {
  264         struct nd_defrouter dr0;
  265         u_int32_t advreachable = nd_ra->nd_ra_reachable;
  266 
  267         /* remember if this is a multicasted advertisement */
  268         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
  269                 mcast = 1;
  270 
  271         bzero(&dr0, sizeof(dr0));
  272         dr0.rtaddr = saddr6;
  273         dr0.flags  = nd_ra->nd_ra_flags_reserved;
  274         dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
  275         dr0.expire = time_second + dr0.rtlifetime;
  276         dr0.ifp = ifp;
  277         /* unspecified or not? (RFC 2461 6.3.4) */
  278         if (advreachable) {
  279                 advreachable = ntohl(advreachable);
  280                 if (advreachable <= MAX_REACHABLE_TIME &&
  281                     ndi->basereachable != advreachable) {
  282                         ndi->basereachable = advreachable;
  283                         ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
  284                         ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
  285                 }
  286         }
  287         if (nd_ra->nd_ra_retransmit)
  288                 ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
  289         if (nd_ra->nd_ra_curhoplimit)
  290                 ndi->chlim = nd_ra->nd_ra_curhoplimit;
  291         dr = defrtrlist_update(&dr0);
  292     }
  293 
  294         /*
  295          * prefix
  296          */
  297         if (ndopts.nd_opts_pi) {
  298                 struct nd_opt_hdr *pt;
  299                 struct nd_opt_prefix_info *pi = NULL;
  300                 struct nd_prefixctl pr;
  301 
  302                 for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
  303                      pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
  304                      pt = (struct nd_opt_hdr *)((caddr_t)pt +
  305                                                 (pt->nd_opt_len << 3))) {
  306                         if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
  307                                 continue;
  308                         pi = (struct nd_opt_prefix_info *)pt;
  309 
  310                         if (pi->nd_opt_pi_len != 4) {
  311                                 nd6log((LOG_INFO,
  312                                     "nd6_ra_input: invalid option "
  313                                     "len %d for prefix information option, "
  314                                     "ignored\n", pi->nd_opt_pi_len));
  315                                 continue;
  316                         }
  317 
  318                         if (128 < pi->nd_opt_pi_prefix_len) {
  319                                 nd6log((LOG_INFO,
  320                                     "nd6_ra_input: invalid prefix "
  321                                     "len %d for prefix information option, "
  322                                     "ignored\n", pi->nd_opt_pi_prefix_len));
  323                                 continue;
  324                         }
  325 
  326                         if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
  327                          || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
  328                                 nd6log((LOG_INFO,
  329                                     "nd6_ra_input: invalid prefix "
  330                                     "%s, ignored\n",
  331                                     ip6_sprintf(ip6bufs,
  332                                         &pi->nd_opt_pi_prefix)));
  333                                 continue;
  334                         }
  335 
  336                         bzero(&pr, sizeof(pr));
  337                         pr.ndpr_prefix.sin6_family = AF_INET6;
  338                         pr.ndpr_prefix.sin6_len = sizeof(pr.ndpr_prefix);
  339                         pr.ndpr_prefix.sin6_addr = pi->nd_opt_pi_prefix;
  340                         pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;
  341 
  342                         pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
  343                             ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
  344                         pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
  345                             ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
  346                         pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
  347                         pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
  348                         pr.ndpr_pltime = ntohl(pi->nd_opt_pi_preferred_time);
  349                         (void)prelist_update(&pr, dr, m, mcast);
  350                 }
  351         }
  352 
  353         /*
  354          * MTU
  355          */
  356         if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
  357                 u_long mtu;
  358                 u_long maxmtu;
  359 
  360                 mtu = (u_long)ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
  361 
  362                 /* lower bound */
  363                 if (mtu < IPV6_MMTU) {
  364                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
  365                             "mtu=%lu sent from %s, ignoring\n",
  366                             mtu, ip6_sprintf(ip6bufs, &ip6->ip6_src)));
  367                         goto skip;
  368                 }
  369 
  370                 /* upper bound */
  371                 maxmtu = (ndi->maxmtu && ndi->maxmtu < ifp->if_mtu)
  372                     ? ndi->maxmtu : ifp->if_mtu;
  373                 if (mtu <= maxmtu) {
  374                         int change = (ndi->linkmtu != mtu);
  375 
  376                         ndi->linkmtu = mtu;
  377                         if (change) /* in6_maxmtu may change */
  378                                 in6_setmaxmtu();
  379                 } else {
  380                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
  381                             "mtu=%lu sent from %s; "
  382                             "exceeds maxmtu %lu, ignoring\n",
  383                             mtu, ip6_sprintf(ip6bufs, &ip6->ip6_src), maxmtu));
  384                 }
  385         }
  386 
  387  skip:
  388 
  389         /*
  390          * Source link layer address
  391          */
  392     {
  393         char *lladdr = NULL;
  394         int lladdrlen = 0;
  395 
  396         if (ndopts.nd_opts_src_lladdr) {
  397                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  398                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  399         }
  400 
  401         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  402                 nd6log((LOG_INFO,
  403                     "nd6_ra_input: lladdrlen mismatch for %s "
  404                     "(if %d, RA packet %d)\n", ip6_sprintf(ip6bufs, &saddr6),
  405                     ifp->if_addrlen, lladdrlen - 2));
  406                 goto bad;
  407         }
  408 
  409         nd6_cache_lladdr(ifp, &saddr6, lladdr,
  410             lladdrlen, ND_ROUTER_ADVERT, 0);
  411 
  412         /*
  413          * Installing a link-layer address might change the state of the
  414          * router's neighbor cache, which might also affect our on-link
  415          * detection of adveritsed prefixes.
  416          */
  417         pfxlist_onlink_check();
  418     }
  419 
  420  freeit:
  421         m_freem(m);
  422         return;
  423 
  424  bad:
  425         icmp6stat.icp6s_badra++;
  426         m_freem(m);
  427 }
  428 
  429 /*
  430  * default router list proccessing sub routines
  431  */
  432 
  433 /* tell the change to user processes watching the routing socket. */
  434 static void
  435 nd6_rtmsg(int cmd, struct rtentry *rt)
  436 {
  437         struct rt_addrinfo info;
  438 
  439         bzero((caddr_t)&info, sizeof(info));
  440         info.rti_info[RTAX_DST] = rt_key(rt);
  441         info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
  442         info.rti_info[RTAX_NETMASK] = rt_mask(rt);
  443         if (rt->rt_ifp) {
  444                 info.rti_info[RTAX_IFP] =
  445                     TAILQ_FIRST(&rt->rt_ifp->if_addrlist)->ifa_addr;
  446                 info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
  447         }
  448 
  449         rt_missmsg(cmd, &info, rt->rt_flags, 0);
  450 }
  451 
  452 static void
  453 defrouter_addreq(struct nd_defrouter *new)
  454 {
  455         struct sockaddr_in6 def, mask, gate;
  456         struct rtentry *newrt = NULL;
  457         int s;
  458         int error;
  459 
  460         bzero(&def, sizeof(def));
  461         bzero(&mask, sizeof(mask));
  462         bzero(&gate, sizeof(gate));
  463 
  464         def.sin6_len = mask.sin6_len = gate.sin6_len =
  465             sizeof(struct sockaddr_in6);
  466         def.sin6_family = gate.sin6_family = AF_INET6;
  467         gate.sin6_addr = new->rtaddr;
  468 
  469         s = splnet();
  470         error = rtrequest(RTM_ADD, (struct sockaddr *)&def,
  471             (struct sockaddr *)&gate, (struct sockaddr *)&mask,
  472             RTF_GATEWAY, &newrt);
  473         if (newrt) {
  474                 RT_LOCK(newrt);
  475                 nd6_rtmsg(RTM_ADD, newrt); /* tell user process */
  476                 RT_REMREF(newrt);
  477                 RT_UNLOCK(newrt);
  478         }
  479         if (error == 0)
  480                 new->installed = 1;
  481         splx(s);
  482         return;
  483 }
  484 
  485 struct nd_defrouter *
  486 defrouter_lookup(struct in6_addr *addr, struct ifnet *ifp)
  487 {
  488         struct nd_defrouter *dr;
  489 
  490         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  491              dr = TAILQ_NEXT(dr, dr_entry)) {
  492                 if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr))
  493                         return (dr);
  494         }
  495 
  496         return (NULL);          /* search failed */
  497 }
  498 
  499 /*
  500  * Remove the default route for a given router.
  501  * This is just a subroutine function for defrouter_select(), and should
  502  * not be called from anywhere else.
  503  */
  504 static void
  505 defrouter_delreq(struct nd_defrouter *dr)
  506 {
  507         struct sockaddr_in6 def, mask, gate;
  508         struct rtentry *oldrt = NULL;
  509 
  510         bzero(&def, sizeof(def));
  511         bzero(&mask, sizeof(mask));
  512         bzero(&gate, sizeof(gate));
  513 
  514         def.sin6_len = mask.sin6_len = gate.sin6_len =
  515             sizeof(struct sockaddr_in6);
  516         def.sin6_family = gate.sin6_family = AF_INET6;
  517         gate.sin6_addr = dr->rtaddr;
  518 
  519         rtrequest(RTM_DELETE, (struct sockaddr *)&def,
  520             (struct sockaddr *)&gate,
  521             (struct sockaddr *)&mask, RTF_GATEWAY, &oldrt);
  522         if (oldrt) {
  523                 nd6_rtmsg(RTM_DELETE, oldrt);
  524                 RTFREE(oldrt);
  525         }
  526 
  527         dr->installed = 0;
  528 }
  529 
  530 /*
  531  * remove all default routes from default router list
  532  */
  533 void
  534 defrouter_reset(void)
  535 {
  536         struct nd_defrouter *dr;
  537 
  538         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  539              dr = TAILQ_NEXT(dr, dr_entry))
  540                 defrouter_delreq(dr);
  541 
  542         /*
  543          * XXX should we also nuke any default routers in the kernel, by
  544          * going through them by rtalloc1()?
  545          */
  546 }
  547 
  548 void
  549 defrtrlist_del(struct nd_defrouter *dr)
  550 {
  551         struct nd_defrouter *deldr = NULL;
  552         struct nd_prefix *pr;
  553 
  554         /*
  555          * Flush all the routing table entries that use the router
  556          * as a next hop.
  557          */
  558         if (!ip6_forwarding && ip6_accept_rtadv) /* XXX: better condition? */
  559                 rt6_flush(&dr->rtaddr, dr->ifp);
  560 
  561         if (dr->installed) {
  562                 deldr = dr;
  563                 defrouter_delreq(dr);
  564         }
  565         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  566 
  567         /*
  568          * Also delete all the pointers to the router in each prefix lists.
  569          */
  570         for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
  571                 struct nd_pfxrouter *pfxrtr;
  572                 if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
  573                         pfxrtr_del(pfxrtr);
  574         }
  575         pfxlist_onlink_check();
  576 
  577         /*
  578          * If the router is the primary one, choose a new one.
  579          * Note that defrouter_select() will remove the current gateway
  580          * from the routing table.
  581          */
  582         if (deldr)
  583                 defrouter_select();
  584 
  585         free(dr, M_IP6NDP);
  586 }
  587 
  588 /*
  589  * Default Router Selection according to Section 6.3.6 of RFC 2461 and
  590  * draft-ietf-ipngwg-router-selection:
  591  * 1) Routers that are reachable or probably reachable should be preferred.
  592  *    If we have more than one (probably) reachable router, prefer ones
  593  *    with the highest router preference.
  594  * 2) When no routers on the list are known to be reachable or
  595  *    probably reachable, routers SHOULD be selected in a round-robin
  596  *    fashion, regardless of router preference values.
  597  * 3) If the Default Router List is empty, assume that all
  598  *    destinations are on-link.
  599  *
  600  * We assume nd_defrouter is sorted by router preference value.
  601  * Since the code below covers both with and without router preference cases,
  602  * we do not need to classify the cases by ifdef.
  603  *
  604  * At this moment, we do not try to install more than one default router,
  605  * even when the multipath routing is available, because we're not sure about
  606  * the benefits for stub hosts comparing to the risk of making the code
  607  * complicated and the possibility of introducing bugs.
  608  */
  609 void
  610 defrouter_select(void)
  611 {
  612         int s = splnet();
  613         struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
  614         struct rtentry *rt = NULL;
  615         struct llinfo_nd6 *ln = NULL;
  616 
  617         /*
  618          * This function should be called only when acting as an autoconfigured
  619          * host.  Although the remaining part of this function is not effective
  620          * if the node is not an autoconfigured host, we explicitly exclude
  621          * such cases here for safety.
  622          */
  623         if (ip6_forwarding || !ip6_accept_rtadv) {
  624                 nd6log((LOG_WARNING,
  625                     "defrouter_select: called unexpectedly (forwarding=%d, "
  626                     "accept_rtadv=%d)\n", ip6_forwarding, ip6_accept_rtadv));
  627                 splx(s);
  628                 return;
  629         }
  630 
  631         /*
  632          * Let's handle easy case (3) first:
  633          * If default router list is empty, there's nothing to be done.
  634          */
  635         if (!TAILQ_FIRST(&nd_defrouter)) {
  636                 splx(s);
  637                 return;
  638         }
  639 
  640         /*
  641          * Search for a (probably) reachable router from the list.
  642          * We just pick up the first reachable one (if any), assuming that
  643          * the ordering rule of the list described in defrtrlist_update().
  644          */
  645         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  646              dr = TAILQ_NEXT(dr, dr_entry)) {
  647                 if (selected_dr == NULL &&
  648                     (rt = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) &&
  649                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
  650                     ND6_IS_LLINFO_PROBREACH(ln)) {
  651                         selected_dr = dr;
  652                 }
  653 
  654                 if (dr->installed && installed_dr == NULL)
  655                         installed_dr = dr;
  656                 else if (dr->installed && installed_dr) {
  657                         /* this should not happen.  warn for diagnosis. */
  658                         log(LOG_ERR, "defrouter_select: more than one router"
  659                             " is installed\n");
  660                 }
  661         }
  662         /*
  663          * If none of the default routers was found to be reachable,
  664          * round-robin the list regardless of preference.
  665          * Otherwise, if we have an installed router, check if the selected
  666          * (reachable) router should really be preferred to the installed one.
  667          * We only prefer the new router when the old one is not reachable
  668          * or when the new one has a really higher preference value.
  669          */
  670         if (selected_dr == NULL) {
  671                 if (installed_dr == NULL || !TAILQ_NEXT(installed_dr, dr_entry))
  672                         selected_dr = TAILQ_FIRST(&nd_defrouter);
  673                 else
  674                         selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
  675         } else if (installed_dr &&
  676             (rt = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp)) &&
  677             (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
  678             ND6_IS_LLINFO_PROBREACH(ln) &&
  679             rtpref(selected_dr) <= rtpref(installed_dr)) {
  680                 selected_dr = installed_dr;
  681         }
  682 
  683         /*
  684          * If the selected router is different than the installed one,
  685          * remove the installed router and install the selected one.
  686          * Note that the selected router is never NULL here.
  687          */
  688         if (installed_dr != selected_dr) {
  689                 if (installed_dr)
  690                         defrouter_delreq(installed_dr);
  691                 defrouter_addreq(selected_dr);
  692         }
  693 
  694         splx(s);
  695         return;
  696 }
  697 
  698 /*
  699  * for default router selection
  700  * regards router-preference field as a 2-bit signed integer
  701  */
  702 static int
  703 rtpref(struct nd_defrouter *dr)
  704 {
  705         switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
  706         case ND_RA_FLAG_RTPREF_HIGH:
  707                 return (RTPREF_HIGH);
  708         case ND_RA_FLAG_RTPREF_MEDIUM:
  709         case ND_RA_FLAG_RTPREF_RSV:
  710                 return (RTPREF_MEDIUM);
  711         case ND_RA_FLAG_RTPREF_LOW:
  712                 return (RTPREF_LOW);
  713         default:
  714                 /*
  715                  * This case should never happen.  If it did, it would mean a
  716                  * serious bug of kernel internal.  We thus always bark here.
  717                  * Or, can we even panic?
  718                  */
  719                 log(LOG_ERR, "rtpref: impossible RA flag %x\n", dr->flags);
  720                 return (RTPREF_INVALID);
  721         }
  722         /* NOTREACHED */
  723 }
  724 
  725 static struct nd_defrouter *
  726 defrtrlist_update(struct nd_defrouter *new)
  727 {
  728         struct nd_defrouter *dr, *n;
  729         int s = splnet();
  730 
  731         if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
  732                 /* entry exists */
  733                 if (new->rtlifetime == 0) {
  734                         defrtrlist_del(dr);
  735                         dr = NULL;
  736                 } else {
  737                         int oldpref = rtpref(dr);
  738 
  739                         /* override */
  740                         dr->flags = new->flags; /* xxx flag check */
  741                         dr->rtlifetime = new->rtlifetime;
  742                         dr->expire = new->expire;
  743 
  744                         /*
  745                          * If the preference does not change, there's no need
  746                          * to sort the entries.
  747                          */
  748                         if (rtpref(new) == oldpref) {
  749                                 splx(s);
  750                                 return (dr);
  751                         }
  752 
  753                         /*
  754                          * preferred router may be changed, so relocate
  755                          * this router.
  756                          * XXX: calling TAILQ_REMOVE directly is a bad manner.
  757                          * However, since defrtrlist_del() has many side
  758                          * effects, we intentionally do so here.
  759                          * defrouter_select() below will handle routing
  760                          * changes later.
  761                          */
  762                         TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
  763                         n = dr;
  764                         goto insert;
  765                 }
  766                 splx(s);
  767                 return (dr);
  768         }
  769 
  770         /* entry does not exist */
  771         if (new->rtlifetime == 0) {
  772                 splx(s);
  773                 return (NULL);
  774         }
  775 
  776         n = (struct nd_defrouter *)malloc(sizeof(*n), M_IP6NDP, M_NOWAIT);
  777         if (n == NULL) {
  778                 splx(s);
  779                 return (NULL);
  780         }
  781         bzero(n, sizeof(*n));
  782         *n = *new;
  783 
  784 insert:
  785         /*
  786          * Insert the new router in the Default Router List;
  787          * The Default Router List should be in the descending order
  788          * of router-preferece.  Routers with the same preference are
  789          * sorted in the arriving time order.
  790          */
  791 
  792         /* insert at the end of the group */
  793         for (dr = TAILQ_FIRST(&nd_defrouter); dr;
  794              dr = TAILQ_NEXT(dr, dr_entry)) {
  795                 if (rtpref(n) > rtpref(dr))
  796                         break;
  797         }
  798         if (dr)
  799                 TAILQ_INSERT_BEFORE(dr, n, dr_entry);
  800         else
  801                 TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);
  802 
  803         defrouter_select();
  804 
  805         splx(s);
  806 
  807         return (n);
  808 }
  809 
  810 static struct nd_pfxrouter *
  811 pfxrtr_lookup(struct nd_prefix *pr, struct nd_defrouter *dr)
  812 {
  813         struct nd_pfxrouter *search;
  814 
  815         for (search = pr->ndpr_advrtrs.lh_first; search; search = search->pfr_next) {
  816                 if (search->router == dr)
  817                         break;
  818         }
  819 
  820         return (search);
  821 }
  822 
  823 static void
  824 pfxrtr_add(struct nd_prefix *pr, struct nd_defrouter *dr)
  825 {
  826         struct nd_pfxrouter *new;
  827 
  828         new = (struct nd_pfxrouter *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  829         if (new == NULL)
  830                 return;
  831         bzero(new, sizeof(*new));
  832         new->router = dr;
  833 
  834         LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
  835 
  836         pfxlist_onlink_check();
  837 }
  838 
  839 static void
  840 pfxrtr_del(struct nd_pfxrouter *pfr)
  841 {
  842         LIST_REMOVE(pfr, pfr_entry);
  843         free(pfr, M_IP6NDP);
  844 }
  845 
  846 struct nd_prefix *
  847 nd6_prefix_lookup(struct nd_prefixctl *key)
  848 {
  849         struct nd_prefix *search;
  850 
  851         for (search = nd_prefix.lh_first; search; search = search->ndpr_next) {
  852                 if (key->ndpr_ifp == search->ndpr_ifp &&
  853                     key->ndpr_plen == search->ndpr_plen &&
  854                     in6_are_prefix_equal(&key->ndpr_prefix.sin6_addr,
  855                     &search->ndpr_prefix.sin6_addr, key->ndpr_plen)) {
  856                         break;
  857                 }
  858         }
  859 
  860         return (search);
  861 }
  862 
  863 int
  864 nd6_prelist_add(struct nd_prefixctl *pr, struct nd_defrouter *dr,
  865     struct nd_prefix **newp)
  866 {
  867         struct nd_prefix *new = NULL;
  868         int error = 0;
  869         int i, s;
  870         char ip6buf[INET6_ADDRSTRLEN];
  871 
  872         new = (struct nd_prefix *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  873         if (new == NULL)
  874                 return(ENOMEM);
  875         bzero(new, sizeof(*new));
  876         new->ndpr_ifp = pr->ndpr_ifp;
  877         new->ndpr_prefix = pr->ndpr_prefix;
  878         new->ndpr_plen = pr->ndpr_plen;
  879         new->ndpr_vltime = pr->ndpr_vltime;
  880         new->ndpr_pltime = pr->ndpr_pltime;
  881         new->ndpr_flags = pr->ndpr_flags;
  882         if ((error = in6_init_prefix_ltimes(new)) != 0) {
  883                 free(new, M_IP6NDP);
  884                 return(error);
  885         }
  886         new->ndpr_lastupdate = time_second;
  887         if (newp != NULL)
  888                 *newp = new;
  889 
  890         /* initialization */
  891         LIST_INIT(&new->ndpr_advrtrs);
  892         in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
  893         /* make prefix in the canonical form */
  894         for (i = 0; i < 4; i++)
  895                 new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
  896                     new->ndpr_mask.s6_addr32[i];
  897 
  898         s = splnet();
  899         /* link ndpr_entry to nd_prefix list */
  900         LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
  901         splx(s);
  902 
  903         /* ND_OPT_PI_FLAG_ONLINK processing */
  904         if (new->ndpr_raf_onlink) {
  905                 int e;
  906 
  907                 if ((e = nd6_prefix_onlink(new)) != 0) {
  908                         nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
  909                             "the prefix %s/%d on-link on %s (errno=%d)\n",
  910                             ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
  911                             pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  912                         /* proceed anyway. XXX: is it correct? */
  913                 }
  914         }
  915 
  916         if (dr)
  917                 pfxrtr_add(new, dr);
  918 
  919         return 0;
  920 }
  921 
  922 void
  923 prelist_remove(struct nd_prefix *pr)
  924 {
  925         struct nd_pfxrouter *pfr, *next;
  926         int e, s;
  927         char ip6buf[INET6_ADDRSTRLEN];
  928 
  929         /* make sure to invalidate the prefix until it is really freed. */
  930         pr->ndpr_vltime = 0;
  931         pr->ndpr_pltime = 0;
  932 
  933         /*
  934          * Though these flags are now meaningless, we'd rather keep the value
  935          * of pr->ndpr_raf_onlink and pr->ndpr_raf_auto not to confuse users
  936          * when executing "ndp -p".
  937          */
  938 
  939         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
  940             (e = nd6_prefix_offlink(pr)) != 0) {
  941                 nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
  942                     "on %s, errno=%d\n",
  943                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
  944                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  945                 /* what should we do? */
  946         }
  947 
  948         if (pr->ndpr_refcnt > 0)
  949                 return;         /* notice here? */
  950 
  951         s = splnet();
  952 
  953         /* unlink ndpr_entry from nd_prefix list */
  954         LIST_REMOVE(pr, ndpr_entry);
  955 
  956         /* free list of routers that adversed the prefix */
  957         for (pfr = pr->ndpr_advrtrs.lh_first; pfr; pfr = next) {
  958                 next = pfr->pfr_next;
  959 
  960                 free(pfr, M_IP6NDP);
  961         }
  962         splx(s);
  963 
  964         free(pr, M_IP6NDP);
  965 
  966         pfxlist_onlink_check();
  967 }
  968 
  969 /*
  970  * dr - may be NULL
  971  */
  972 
  973 static int
  974 prelist_update(struct nd_prefixctl *new, struct nd_defrouter *dr,
  975     struct mbuf *m, int mcast)
  976 {
  977         struct in6_ifaddr *ia6 = NULL, *ia6_match = NULL;
  978         struct ifaddr *ifa;
  979         struct ifnet *ifp = new->ndpr_ifp;
  980         struct nd_prefix *pr;
  981         int s = splnet();
  982         int error = 0;
  983         int newprefix = 0;
  984         int auth;
  985         struct in6_addrlifetime lt6_tmp;
  986         char ip6buf[INET6_ADDRSTRLEN];
  987 
  988         auth = 0;
  989         if (m) {
  990                 /*
  991                  * Authenticity for NA consists authentication for
  992                  * both IP header and IP datagrams, doesn't it ?
  993                  */
  994 #if defined(M_AUTHIPHDR) && defined(M_AUTHIPDGM)
  995                 auth = ((m->m_flags & M_AUTHIPHDR) &&
  996                     (m->m_flags & M_AUTHIPDGM));
  997 #endif
  998         }
  999 
 1000         if ((pr = nd6_prefix_lookup(new)) != NULL) {
 1001                 /*
 1002                  * nd6_prefix_lookup() ensures that pr and new have the same
 1003                  * prefix on a same interface.
 1004                  */
 1005 
 1006                 /*
 1007                  * Update prefix information.  Note that the on-link (L) bit
 1008                  * and the autonomous (A) bit should NOT be changed from 1
 1009                  * to 0.
 1010                  */
 1011                 if (new->ndpr_raf_onlink == 1)
 1012                         pr->ndpr_raf_onlink = 1;
 1013                 if (new->ndpr_raf_auto == 1)
 1014                         pr->ndpr_raf_auto = 1;
 1015                 if (new->ndpr_raf_onlink) {
 1016                         pr->ndpr_vltime = new->ndpr_vltime;
 1017                         pr->ndpr_pltime = new->ndpr_pltime;
 1018                         (void)in6_init_prefix_ltimes(pr); /* XXX error case? */
 1019                         pr->ndpr_lastupdate = time_second;
 1020                 }
 1021 
 1022                 if (new->ndpr_raf_onlink &&
 1023                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1024                         int e;
 1025 
 1026                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1027                                 nd6log((LOG_ERR,
 1028                                     "prelist_update: failed to make "
 1029                                     "the prefix %s/%d on-link on %s "
 1030                                     "(errno=%d)\n",
 1031                                     ip6_sprintf(ip6buf,
 1032                                             &pr->ndpr_prefix.sin6_addr),
 1033                                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
 1034                                 /* proceed anyway. XXX: is it correct? */
 1035                         }
 1036                 }
 1037 
 1038                 if (dr && pfxrtr_lookup(pr, dr) == NULL)
 1039                         pfxrtr_add(pr, dr);
 1040         } else {
 1041                 struct nd_prefix *newpr = NULL;
 1042 
 1043                 newprefix = 1;
 1044 
 1045                 if (new->ndpr_vltime == 0)
 1046                         goto end;
 1047                 if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
 1048                         goto end;
 1049 
 1050                 error = nd6_prelist_add(new, dr, &newpr);
 1051                 if (error != 0 || newpr == NULL) {
 1052                         nd6log((LOG_NOTICE, "prelist_update: "
 1053                             "nd6_prelist_add failed for %s/%d on %s "
 1054                             "errno=%d, returnpr=%p\n",
 1055                             ip6_sprintf(ip6buf, &new->ndpr_prefix.sin6_addr),
 1056                             new->ndpr_plen, if_name(new->ndpr_ifp),
 1057                             error, newpr));
 1058                         goto end; /* we should just give up in this case. */
 1059                 }
 1060 
 1061                 /*
 1062                  * XXX: from the ND point of view, we can ignore a prefix
 1063                  * with the on-link bit being zero.  However, we need a
 1064                  * prefix structure for references from autoconfigured
 1065                  * addresses.  Thus, we explicitly make sure that the prefix
 1066                  * itself expires now.
 1067                  */
 1068                 if (newpr->ndpr_raf_onlink == 0) {
 1069                         newpr->ndpr_vltime = 0;
 1070                         newpr->ndpr_pltime = 0;
 1071                         in6_init_prefix_ltimes(newpr);
 1072                 }
 1073 
 1074                 pr = newpr;
 1075         }
 1076 
 1077         /*
 1078          * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
 1079          * Note that pr must be non NULL at this point.
 1080          */
 1081 
 1082         /* 5.5.3 (a). Ignore the prefix without the A bit set. */
 1083         if (!new->ndpr_raf_auto)
 1084                 goto end;
 1085 
 1086         /*
 1087          * 5.5.3 (b). the link-local prefix should have been ignored in
 1088          * nd6_ra_input.
 1089          */
 1090 
 1091         /* 5.5.3 (c). Consistency check on lifetimes: pltime <= vltime. */
 1092         if (new->ndpr_pltime > new->ndpr_vltime) {
 1093                 error = EINVAL; /* XXX: won't be used */
 1094                 goto end;
 1095         }
 1096 
 1097         /*
 1098          * 5.5.3 (d).  If the prefix advertised is not equal to the prefix of
 1099          * an address configured by stateless autoconfiguration already in the
 1100          * list of addresses associated with the interface, and the Valid
 1101          * Lifetime is not 0, form an address.  We first check if we have
 1102          * a matching prefix.
 1103          * Note: we apply a clarification in rfc2462bis-02 here.  We only
 1104          * consider autoconfigured addresses while RFC2462 simply said
 1105          * "address".
 1106          */
 1107         TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
 1108                 struct in6_ifaddr *ifa6;
 1109                 u_int32_t remaininglifetime;
 1110 
 1111                 if (ifa->ifa_addr->sa_family != AF_INET6)
 1112                         continue;
 1113 
 1114                 ifa6 = (struct in6_ifaddr *)ifa;
 1115 
 1116                 /*
 1117                  * We only consider autoconfigured addresses as per rfc2462bis.
 1118                  */
 1119                 if (!(ifa6->ia6_flags & IN6_IFF_AUTOCONF))
 1120                         continue;
 1121 
 1122                 /*
 1123                  * Spec is not clear here, but I believe we should concentrate
 1124                  * on unicast (i.e. not anycast) addresses.
 1125                  * XXX: other ia6_flags? detached or duplicated?
 1126                  */
 1127                 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0)
 1128                         continue;
 1129 
 1130                 /*
 1131                  * Ignore the address if it is not associated with a prefix
 1132                  * or is associated with a prefix that is different from this
 1133                  * one.  (pr is never NULL here)
 1134                  */
 1135                 if (ifa6->ia6_ndpr != pr)
 1136                         continue;
 1137 
 1138                 if (ia6_match == NULL) /* remember the first one */
 1139                         ia6_match = ifa6;
 1140 
 1141                 /*
 1142                  * An already autoconfigured address matched.  Now that we
 1143                  * are sure there is at least one matched address, we can
 1144                  * proceed to 5.5.3. (e): update the lifetimes according to the
 1145                  * "two hours" rule and the privacy extension.
 1146                  * We apply some clarifications in rfc2462bis:
 1147                  * - use remaininglifetime instead of storedlifetime as a
 1148                  *   variable name
 1149                  * - remove the dead code in the "two-hour" rule
 1150                  */
 1151 #define TWOHOUR         (120*60)
 1152                 lt6_tmp = ifa6->ia6_lifetime;
 1153 
 1154                 if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME)
 1155                         remaininglifetime = ND6_INFINITE_LIFETIME;
 1156                 else if (time_second - ifa6->ia6_updatetime >
 1157                          lt6_tmp.ia6t_vltime) {
 1158                         /*
 1159                          * The case of "invalid" address.  We should usually
 1160                          * not see this case.
 1161                          */
 1162                         remaininglifetime = 0;
 1163                 } else
 1164                         remaininglifetime = lt6_tmp.ia6t_vltime -
 1165                             (time_second - ifa6->ia6_updatetime);
 1166 
 1167                 /* when not updating, keep the current stored lifetime. */
 1168                 lt6_tmp.ia6t_vltime = remaininglifetime;
 1169 
 1170                 if (TWOHOUR < new->ndpr_vltime ||
 1171                     remaininglifetime < new->ndpr_vltime) {
 1172                         lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1173                 } else if (remaininglifetime <= TWOHOUR) {
 1174                         if (auth) {
 1175                                 lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1176                         }
 1177                 } else {
 1178                         /*
 1179                          * new->ndpr_vltime <= TWOHOUR &&
 1180                          * TWOHOUR < remaininglifetime
 1181                          */
 1182                         lt6_tmp.ia6t_vltime = TWOHOUR;
 1183                 }
 1184 
 1185                 /* The 2 hour rule is not imposed for preferred lifetime. */
 1186                 lt6_tmp.ia6t_pltime = new->ndpr_pltime;
 1187 
 1188                 in6_init_address_ltimes(pr, &lt6_tmp);
 1189 
 1190                 /*
 1191                  * We need to treat lifetimes for temporary addresses
 1192                  * differently, according to
 1193                  * draft-ietf-ipv6-privacy-addrs-v2-01.txt 3.3 (1);
 1194                  * we only update the lifetimes when they are in the maximum
 1195                  * intervals.
 1196                  */
 1197                 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0) {
 1198                         u_int32_t maxvltime, maxpltime;
 1199 
 1200                         if (ip6_temp_valid_lifetime >
 1201                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1202                             ip6_desync_factor)) {
 1203                                 maxvltime = ip6_temp_valid_lifetime -
 1204                                     (time_second - ifa6->ia6_createtime) -
 1205                                     ip6_desync_factor;
 1206                         } else
 1207                                 maxvltime = 0;
 1208                         if (ip6_temp_preferred_lifetime >
 1209                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1210                             ip6_desync_factor)) {
 1211                                 maxpltime = ip6_temp_preferred_lifetime -
 1212                                     (time_second - ifa6->ia6_createtime) -
 1213                                     ip6_desync_factor;
 1214                         } else
 1215                                 maxpltime = 0;
 1216 
 1217                         if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME ||
 1218                             lt6_tmp.ia6t_vltime > maxvltime) {
 1219                                 lt6_tmp.ia6t_vltime = maxvltime;
 1220                         }
 1221                         if (lt6_tmp.ia6t_pltime == ND6_INFINITE_LIFETIME ||
 1222                             lt6_tmp.ia6t_pltime > maxpltime) {
 1223                                 lt6_tmp.ia6t_pltime = maxpltime;
 1224                         }
 1225                 }
 1226                 ifa6->ia6_lifetime = lt6_tmp;
 1227                 ifa6->ia6_updatetime = time_second;
 1228         }
 1229         if (ia6_match == NULL && new->ndpr_vltime) {
 1230                 int ifidlen;
 1231 
 1232                 /*
 1233                  * 5.5.3 (d) (continued)
 1234                  * No address matched and the valid lifetime is non-zero.
 1235                  * Create a new address.
 1236                  */
 1237 
 1238                 /*
 1239                  * Prefix Length check:
 1240                  * If the sum of the prefix length and interface identifier
 1241                  * length does not equal 128 bits, the Prefix Information
 1242                  * option MUST be ignored.  The length of the interface
 1243                  * identifier is defined in a separate link-type specific
 1244                  * document.
 1245                  */
 1246                 ifidlen = in6_if2idlen(ifp);
 1247                 if (ifidlen < 0) {
 1248                         /* this should not happen, so we always log it. */
 1249                         log(LOG_ERR, "prelist_update: IFID undefined (%s)\n",
 1250                             if_name(ifp));
 1251                         goto end;
 1252                 }
 1253                 if (ifidlen + pr->ndpr_plen != 128) {
 1254                         nd6log((LOG_INFO,
 1255                             "prelist_update: invalid prefixlen "
 1256                             "%d for %s, ignored\n",
 1257                             pr->ndpr_plen, if_name(ifp)));
 1258                         goto end;
 1259                 }
 1260 
 1261                 if ((ia6 = in6_ifadd(new, mcast)) != NULL) {
 1262                         /*
 1263                          * note that we should use pr (not new) for reference.
 1264                          */
 1265                         pr->ndpr_refcnt++;
 1266                         ia6->ia6_ndpr = pr;
 1267 
 1268                         /*
 1269                          * RFC 3041 3.3 (2).
 1270                          * When a new public address is created as described
 1271                          * in RFC2462, also create a new temporary address.
 1272                          *
 1273                          * RFC 3041 3.5.
 1274                          * When an interface connects to a new link, a new
 1275                          * randomized interface identifier should be generated
 1276                          * immediately together with a new set of temporary
 1277                          * addresses.  Thus, we specifiy 1 as the 2nd arg of
 1278                          * in6_tmpifadd().
 1279                          */
 1280                         if (ip6_use_tempaddr) {
 1281                                 int e;
 1282                                 if ((e = in6_tmpifadd(ia6, 1, 1)) != 0) {
 1283                                         nd6log((LOG_NOTICE, "prelist_update: "
 1284                                             "failed to create a temporary "
 1285                                             "address, errno=%d\n",
 1286                                             e));
 1287                                 }
 1288                         }
 1289 
 1290                         /*
 1291                          * A newly added address might affect the status
 1292                          * of other addresses, so we check and update it.
 1293                          * XXX: what if address duplication happens?
 1294                          */
 1295                         pfxlist_onlink_check();
 1296                 } else {
 1297                         /* just set an error. do not bark here. */
 1298                         error = EADDRNOTAVAIL; /* XXX: might be unused. */
 1299                 }
 1300         }
 1301 
 1302  end:
 1303         splx(s);
 1304         return error;
 1305 }
 1306 
 1307 /*
 1308  * A supplement function used in the on-link detection below;
 1309  * detect if a given prefix has a (probably) reachable advertising router.
 1310  * XXX: lengthy function name...
 1311  */
 1312 static struct nd_pfxrouter *
 1313 find_pfxlist_reachable_router(struct nd_prefix *pr)
 1314 {
 1315         struct nd_pfxrouter *pfxrtr;
 1316         struct rtentry *rt;
 1317         struct llinfo_nd6 *ln;
 1318 
 1319         for (pfxrtr = LIST_FIRST(&pr->ndpr_advrtrs); pfxrtr;
 1320              pfxrtr = LIST_NEXT(pfxrtr, pfr_entry)) {
 1321                 if ((rt = nd6_lookup(&pfxrtr->router->rtaddr, 0,
 1322                     pfxrtr->router->ifp)) &&
 1323                     (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
 1324                     ND6_IS_LLINFO_PROBREACH(ln))
 1325                         break;  /* found */
 1326         }
 1327 
 1328         return (pfxrtr);
 1329 }
 1330 
 1331 /*
 1332  * Check if each prefix in the prefix list has at least one available router
 1333  * that advertised the prefix (a router is "available" if its neighbor cache
 1334  * entry is reachable or probably reachable).
 1335  * If the check fails, the prefix may be off-link, because, for example,
 1336  * we have moved from the network but the lifetime of the prefix has not
 1337  * expired yet.  So we should not use the prefix if there is another prefix
 1338  * that has an available router.
 1339  * But, if there is no prefix that has an available router, we still regards
 1340  * all the prefixes as on-link.  This is because we can't tell if all the
 1341  * routers are simply dead or if we really moved from the network and there
 1342  * is no router around us.
 1343  */
 1344 void
 1345 pfxlist_onlink_check()
 1346 {
 1347         struct nd_prefix *pr;
 1348         struct in6_ifaddr *ifa;
 1349         struct nd_defrouter *dr;
 1350         struct nd_pfxrouter *pfxrtr = NULL;
 1351 
 1352         /*
 1353          * Check if there is a prefix that has a reachable advertising
 1354          * router.
 1355          */
 1356         for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1357                 if (pr->ndpr_raf_onlink && find_pfxlist_reachable_router(pr))
 1358                         break;
 1359         }
 1360 
 1361         /*
 1362          * If we have no such prefix, check whether we still have a router
 1363          * that does not advertise any prefixes.
 1364          */
 1365         if (pr == NULL) {
 1366                 for (dr = TAILQ_FIRST(&nd_defrouter); dr;
 1367                     dr = TAILQ_NEXT(dr, dr_entry)) {
 1368                         struct nd_prefix *pr0;
 1369 
 1370                         for (pr0 = nd_prefix.lh_first; pr0;
 1371                             pr0 = pr0->ndpr_next) {
 1372                                 if ((pfxrtr = pfxrtr_lookup(pr0, dr)) != NULL)
 1373                                         break;
 1374                         }
 1375                         if (pfxrtr != NULL)
 1376                                 break;
 1377                 }
 1378         }
 1379         if (pr != NULL || (TAILQ_FIRST(&nd_defrouter) && pfxrtr == NULL)) {
 1380                 /*
 1381                  * There is at least one prefix that has a reachable router,
 1382                  * or at least a router which probably does not advertise
 1383                  * any prefixes.  The latter would be the case when we move
 1384                  * to a new link where we have a router that does not provide
 1385                  * prefixes and we configure an address by hand.
 1386                  * Detach prefixes which have no reachable advertising
 1387                  * router, and attach other prefixes.
 1388                  */
 1389                 for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1390                         /* XXX: a link-local prefix should never be detached */
 1391                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1392                                 continue;
 1393 
 1394                         /*
 1395                          * we aren't interested in prefixes without the L bit
 1396                          * set.
 1397                          */
 1398                         if (pr->ndpr_raf_onlink == 0)
 1399                                 continue;
 1400 
 1401                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1402                             find_pfxlist_reachable_router(pr) == NULL)
 1403                                 pr->ndpr_stateflags |= NDPRF_DETACHED;
 1404                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1405                             find_pfxlist_reachable_router(pr) != 0)
 1406                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1407                 }
 1408         } else {
 1409                 /* there is no prefix that has a reachable router */
 1410                 for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1411                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1412                                 continue;
 1413 
 1414                         if (pr->ndpr_raf_onlink == 0)
 1415                                 continue;
 1416 
 1417                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1418                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1419                 }
 1420         }
 1421 
 1422         /*
 1423          * Remove each interface route associated with a (just) detached
 1424          * prefix, and reinstall the interface route for a (just) attached
 1425          * prefix.  Note that all attempt of reinstallation does not
 1426          * necessarily success, when a same prefix is shared among multiple
 1427          * interfaces.  Such cases will be handled in nd6_prefix_onlink,
 1428          * so we don't have to care about them.
 1429          */
 1430         for (pr = nd_prefix.lh_first; pr; pr = pr->ndpr_next) {
 1431                 int e;
 1432                 char ip6buf[INET6_ADDRSTRLEN];
 1433 
 1434                 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1435                         continue;
 1436 
 1437                 if (pr->ndpr_raf_onlink == 0)
 1438                         continue;
 1439 
 1440                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1441                     (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1442                         if ((e = nd6_prefix_offlink(pr)) != 0) {
 1443                                 nd6log((LOG_ERR,
 1444                                     "pfxlist_onlink_check: failed to "
 1445                                     "make %s/%d offlink, errno=%d\n",
 1446                                     ip6_sprintf(ip6buf,
 1447                                             &pr->ndpr_prefix.sin6_addr),
 1448                                             pr->ndpr_plen, e));
 1449                         }
 1450                 }
 1451                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1452                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0 &&
 1453                     pr->ndpr_raf_onlink) {
 1454                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1455                                 nd6log((LOG_ERR,
 1456                                     "pfxlist_onlink_check: failed to "
 1457                                     "make %s/%d onlink, errno=%d\n",
 1458                                     ip6_sprintf(ip6buf,
 1459                                             &pr->ndpr_prefix.sin6_addr),
 1460                                             pr->ndpr_plen, e));
 1461                         }
 1462                 }
 1463         }
 1464 
 1465         /*
 1466          * Changes on the prefix status might affect address status as well.
 1467          * Make sure that all addresses derived from an attached prefix are
 1468          * attached, and that all addresses derived from a detached prefix are
 1469          * detached.  Note, however, that a manually configured address should
 1470          * always be attached.
 1471          * The precise detection logic is same as the one for prefixes.
 1472          */
 1473         for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1474                 if (!(ifa->ia6_flags & IN6_IFF_AUTOCONF))
 1475                         continue;
 1476 
 1477                 if (ifa->ia6_ndpr == NULL) {
 1478                         /*
 1479                          * This can happen when we first configure the address
 1480                          * (i.e. the address exists, but the prefix does not).
 1481                          * XXX: complicated relationships...
 1482                          */
 1483                         continue;
 1484                 }
 1485 
 1486                 if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
 1487                         break;
 1488         }
 1489         if (ifa) {
 1490                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1491                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1492                                 continue;
 1493 
 1494                         if (ifa->ia6_ndpr == NULL) /* XXX: see above. */
 1495                                 continue;
 1496 
 1497                         if (find_pfxlist_reachable_router(ifa->ia6_ndpr)) {
 1498                                 if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1499                                         ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1500                                         ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1501                                         nd6_dad_start((struct ifaddr *)ifa, 0);
 1502                                 }
 1503                         } else {
 1504                                 ifa->ia6_flags |= IN6_IFF_DETACHED;
 1505                         }
 1506                 }
 1507         }
 1508         else {
 1509                 for (ifa = in6_ifaddr; ifa; ifa = ifa->ia_next) {
 1510                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1511                                 continue;
 1512 
 1513                         if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1514                                 ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1515                                 ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1516                                 /* Do we need a delay in this case? */
 1517                                 nd6_dad_start((struct ifaddr *)ifa, 0);
 1518                         }
 1519                 }
 1520         }
 1521 }
 1522 
 1523 static int
 1524 nd6_prefix_onlink(struct nd_prefix *pr)
 1525 {
 1526         struct ifaddr *ifa;
 1527         struct ifnet *ifp = pr->ndpr_ifp;
 1528         struct sockaddr_in6 mask6;
 1529         struct nd_prefix *opr;
 1530         u_long rtflags;
 1531         int error = 0;
 1532         struct rtentry *rt = NULL;
 1533         char ip6buf[INET6_ADDRSTRLEN];
 1534 
 1535         /* sanity check */
 1536         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1537                 nd6log((LOG_ERR,
 1538                     "nd6_prefix_onlink: %s/%d is already on-link\n",
 1539                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1540                     pr->ndpr_plen));
 1541                 return (EEXIST);
 1542         }
 1543 
 1544         /*
 1545          * Add the interface route associated with the prefix.  Before
 1546          * installing the route, check if there's the same prefix on another
 1547          * interface, and the prefix has already installed the interface route.
 1548          * Although such a configuration is expected to be rare, we explicitly
 1549          * allow it.
 1550          */
 1551         for (opr = nd_prefix.lh_first; opr; opr = opr->ndpr_next) {
 1552                 if (opr == pr)
 1553                         continue;
 1554 
 1555                 if ((opr->ndpr_stateflags & NDPRF_ONLINK) == 0)
 1556                         continue;
 1557 
 1558                 if (opr->ndpr_plen == pr->ndpr_plen &&
 1559                     in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1560                     &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen))
 1561                         return (0);
 1562         }
 1563 
 1564         /*
 1565          * We prefer link-local addresses as the associated interface address.
 1566          */
 1567         /* search for a link-local addr */
 1568         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
 1569             IN6_IFF_NOTREADY | IN6_IFF_ANYCAST);
 1570         if (ifa == NULL) {
 1571                 /* XXX: freebsd does not have ifa_ifwithaf */
 1572                 TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
 1573                         if (ifa->ifa_addr->sa_family == AF_INET6)
 1574                                 break;
 1575                 }
 1576                 /* should we care about ia6_flags? */
 1577         }
 1578         if (ifa == NULL) {
 1579                 /*
 1580                  * This can still happen, when, for example, we receive an RA
 1581                  * containing a prefix with the L bit set and the A bit clear,
 1582                  * after removing all IPv6 addresses on the receiving
 1583                  * interface.  This should, of course, be rare though.
 1584                  */
 1585                 nd6log((LOG_NOTICE,
 1586                     "nd6_prefix_onlink: failed to find any ifaddr"
 1587                     " to add route for a prefix(%s/%d) on %s\n",
 1588                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1589                     pr->ndpr_plen, if_name(ifp)));
 1590                 return (0);
 1591         }
 1592 
 1593         /*
 1594          * in6_ifinit() sets nd6_rtrequest to ifa_rtrequest for all ifaddrs.
 1595          * ifa->ifa_rtrequest = nd6_rtrequest;
 1596          */
 1597         bzero(&mask6, sizeof(mask6));
 1598         mask6.sin6_len = sizeof(mask6);
 1599         mask6.sin6_addr = pr->ndpr_mask;
 1600         rtflags = ifa->ifa_flags | RTF_CLONING | RTF_UP;
 1601         if (nd6_need_cache(ifp)) {
 1602                 /* explicitly set in case ifa_flags does not set the flag. */
 1603                 rtflags |= RTF_CLONING;
 1604         } else {
 1605                 /*
 1606                  * explicitly clear the cloning bit in case ifa_flags sets it.
 1607                  */
 1608                 rtflags &= ~RTF_CLONING;
 1609         }
 1610         error = rtrequest(RTM_ADD, (struct sockaddr *)&pr->ndpr_prefix,
 1611             ifa->ifa_addr, (struct sockaddr *)&mask6, rtflags, &rt);
 1612         if (error == 0) {
 1613                 if (rt != NULL) /* this should be non NULL, though */
 1614                         nd6_rtmsg(RTM_ADD, rt);
 1615                 pr->ndpr_stateflags |= NDPRF_ONLINK;
 1616         } else {
 1617                 char ip6bufg[INET6_ADDRSTRLEN], ip6bufm[INET6_ADDRSTRLEN];
 1618                 nd6log((LOG_ERR, "nd6_prefix_onlink: failed to add route for a"
 1619                     " prefix (%s/%d) on %s, gw=%s, mask=%s, flags=%lx "
 1620                     "errno = %d\n",
 1621                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1622                     pr->ndpr_plen, if_name(ifp),
 1623                     ip6_sprintf(ip6bufg, &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr),
 1624                     ip6_sprintf(ip6bufm, &mask6.sin6_addr), rtflags, error));
 1625         }
 1626 
 1627         if (rt != NULL) {
 1628                 RT_LOCK(rt);
 1629                 RT_REMREF(rt);
 1630                 RT_UNLOCK(rt);
 1631         }
 1632 
 1633         return (error);
 1634 }
 1635 
 1636 static int
 1637 nd6_prefix_offlink(struct nd_prefix *pr)
 1638 {
 1639         int error = 0;
 1640         struct ifnet *ifp = pr->ndpr_ifp;
 1641         struct nd_prefix *opr;
 1642         struct sockaddr_in6 sa6, mask6;
 1643         struct rtentry *rt = NULL;
 1644         char ip6buf[INET6_ADDRSTRLEN];
 1645 
 1646         /* sanity check */
 1647         if ((pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1648                 nd6log((LOG_ERR,
 1649                     "nd6_prefix_offlink: %s/%d is already off-link\n",
 1650                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1651                     pr->ndpr_plen));
 1652                 return (EEXIST);
 1653         }
 1654 
 1655         bzero(&sa6, sizeof(sa6));
 1656         sa6.sin6_family = AF_INET6;
 1657         sa6.sin6_len = sizeof(sa6);
 1658         bcopy(&pr->ndpr_prefix.sin6_addr, &sa6.sin6_addr,
 1659             sizeof(struct in6_addr));
 1660         bzero(&mask6, sizeof(mask6));
 1661         mask6.sin6_family = AF_INET6;
 1662         mask6.sin6_len = sizeof(sa6);
 1663         bcopy(&pr->ndpr_mask, &mask6.sin6_addr, sizeof(struct in6_addr));
 1664         error = rtrequest(RTM_DELETE, (struct sockaddr *)&sa6, NULL,
 1665             (struct sockaddr *)&mask6, 0, &rt);
 1666         if (error == 0) {
 1667                 pr->ndpr_stateflags &= ~NDPRF_ONLINK;
 1668 
 1669                 /* report the route deletion to the routing socket. */
 1670                 if (rt != NULL)
 1671                         nd6_rtmsg(RTM_DELETE, rt);
 1672 
 1673                 /*
 1674                  * There might be the same prefix on another interface,
 1675                  * the prefix which could not be on-link just because we have
 1676                  * the interface route (see comments in nd6_prefix_onlink).
 1677                  * If there's one, try to make the prefix on-link on the
 1678                  * interface.
 1679                  */
 1680                 for (opr = nd_prefix.lh_first; opr; opr = opr->ndpr_next) {
 1681                         if (opr == pr)
 1682                                 continue;
 1683 
 1684                         if ((opr->ndpr_stateflags & NDPRF_ONLINK) != 0)
 1685                                 continue;
 1686 
 1687                         /*
 1688                          * KAME specific: detached prefixes should not be
 1689                          * on-link.
 1690                          */
 1691                         if ((opr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1692                                 continue;
 1693 
 1694                         if (opr->ndpr_plen == pr->ndpr_plen &&
 1695                             in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1696                             &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
 1697                                 int e;
 1698 
 1699                                 if ((e = nd6_prefix_onlink(opr)) != 0) {
 1700                                         nd6log((LOG_ERR,
 1701                                             "nd6_prefix_offlink: failed to "
 1702                                             "recover a prefix %s/%d from %s "
 1703                                             "to %s (errno = %d)\n",
 1704                                             ip6_sprintf(ip6buf,
 1705                                                 &opr->ndpr_prefix.sin6_addr),
 1706                                             opr->ndpr_plen, if_name(ifp),
 1707                                             if_name(opr->ndpr_ifp), e));
 1708                                 }
 1709                         }
 1710                 }
 1711         } else {
 1712                 /* XXX: can we still set the NDPRF_ONLINK flag? */
 1713                 nd6log((LOG_ERR,
 1714                     "nd6_prefix_offlink: failed to delete route: "
 1715                     "%s/%d on %s (errno = %d)\n",
 1716                     ip6_sprintf(ip6buf, &sa6.sin6_addr), pr->ndpr_plen,
 1717                     if_name(ifp), error));
 1718         }
 1719 
 1720         if (rt != NULL) {
 1721                 RTFREE(rt);
 1722         }
 1723 
 1724         return (error);
 1725 }
 1726 
 1727 static struct in6_ifaddr *
 1728 in6_ifadd(struct nd_prefixctl *pr, int mcast)
 1729 {
 1730         struct ifnet *ifp = pr->ndpr_ifp;
 1731         struct ifaddr *ifa;
 1732         struct in6_aliasreq ifra;
 1733         struct in6_ifaddr *ia, *ib;
 1734         int error, plen0;
 1735         struct in6_addr mask;
 1736         int prefixlen = pr->ndpr_plen;
 1737         int updateflags;
 1738         char ip6buf[INET6_ADDRSTRLEN];
 1739 
 1740         in6_prefixlen2mask(&mask, prefixlen);
 1741 
 1742         /*
 1743          * find a link-local address (will be interface ID).
 1744          * Is it really mandatory? Theoretically, a global or a site-local
 1745          * address can be configured without a link-local address, if we
 1746          * have a unique interface identifier...
 1747          *
 1748          * it is not mandatory to have a link-local address, we can generate
 1749          * interface identifier on the fly.  we do this because:
 1750          * (1) it should be the easiest way to find interface identifier.
 1751          * (2) RFC2462 5.4 suggesting the use of the same interface identifier
 1752          * for multiple addresses on a single interface, and possible shortcut
 1753          * of DAD.  we omitted DAD for this reason in the past.
 1754          * (3) a user can prevent autoconfiguration of global address
 1755          * by removing link-local address by hand (this is partly because we
 1756          * don't have other way to control the use of IPv6 on an interface.
 1757          * this has been our design choice - cf. NRL's "ifconfig auto").
 1758          * (4) it is easier to manage when an interface has addresses
 1759          * with the same interface identifier, than to have multiple addresses
 1760          * with different interface identifiers.
 1761          */
 1762         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0); /* 0 is OK? */
 1763         if (ifa)
 1764                 ib = (struct in6_ifaddr *)ifa;
 1765         else
 1766                 return NULL;
 1767 
 1768         /* prefixlen + ifidlen must be equal to 128 */
 1769         plen0 = in6_mask2len(&ib->ia_prefixmask.sin6_addr, NULL);
 1770         if (prefixlen != plen0) {
 1771                 nd6log((LOG_INFO, "in6_ifadd: wrong prefixlen for %s "
 1772                     "(prefix=%d ifid=%d)\n",
 1773                     if_name(ifp), prefixlen, 128 - plen0));
 1774                 return NULL;
 1775         }
 1776 
 1777         /* make ifaddr */
 1778 
 1779         bzero(&ifra, sizeof(ifra));
 1780         /*
 1781          * in6_update_ifa() does not use ifra_name, but we accurately set it
 1782          * for safety.
 1783          */
 1784         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1785         ifra.ifra_addr.sin6_family = AF_INET6;
 1786         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
 1787         /* prefix */
 1788         ifra.ifra_addr.sin6_addr = pr->ndpr_prefix.sin6_addr;
 1789         ifra.ifra_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
 1790         ifra.ifra_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
 1791         ifra.ifra_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
 1792         ifra.ifra_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
 1793 
 1794         /* interface ID */
 1795         ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
 1796             (ib->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
 1797         ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
 1798             (ib->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
 1799         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1800             (ib->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
 1801         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1802             (ib->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);
 1803 
 1804         /* new prefix mask. */
 1805         ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
 1806         ifra.ifra_prefixmask.sin6_family = AF_INET6;
 1807         bcopy(&mask, &ifra.ifra_prefixmask.sin6_addr,
 1808             sizeof(ifra.ifra_prefixmask.sin6_addr));
 1809 
 1810         /* lifetimes. */
 1811         ifra.ifra_lifetime.ia6t_vltime = pr->ndpr_vltime;
 1812         ifra.ifra_lifetime.ia6t_pltime = pr->ndpr_pltime;
 1813 
 1814         /* XXX: scope zone ID? */
 1815 
 1816         ifra.ifra_flags |= IN6_IFF_AUTOCONF; /* obey autoconf */
 1817 
 1818         /*
 1819          * Make sure that we do not have this address already.  This should
 1820          * usually not happen, but we can still see this case, e.g., if we
 1821          * have manually configured the exact address to be configured.
 1822          */
 1823         if (in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr) != NULL) {
 1824                 /* this should be rare enough to make an explicit log */
 1825                 log(LOG_INFO, "in6_ifadd: %s is already configured\n",
 1826                     ip6_sprintf(ip6buf, &ifra.ifra_addr.sin6_addr));
 1827                 return (NULL);
 1828         }
 1829 
 1830         /*
 1831          * Allocate ifaddr structure, link into chain, etc.
 1832          * If we are going to create a new address upon receiving a multicasted
 1833          * RA, we need to impose a random delay before starting DAD.
 1834          * [draft-ietf-ipv6-rfc2462bis-02.txt, Section 5.4.2]
 1835          */
 1836         updateflags = 0;
 1837         if (mcast)
 1838                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1839         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0) {
 1840                 nd6log((LOG_ERR,
 1841                     "in6_ifadd: failed to make ifaddr %s on %s (errno=%d)\n",
 1842                     ip6_sprintf(ip6buf, &ifra.ifra_addr.sin6_addr),
 1843                     if_name(ifp), error));
 1844                 return (NULL);  /* ifaddr must not have been allocated. */
 1845         }
 1846 
 1847         ia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1848 
 1849         return (ia);            /* this is always non-NULL */
 1850 }
 1851 
 1852 /*
 1853  * ia0 - corresponding public address
 1854  */
 1855 int
 1856 in6_tmpifadd(const struct in6_ifaddr *ia0, int forcegen, int delay)
 1857 {
 1858         struct ifnet *ifp = ia0->ia_ifa.ifa_ifp;
 1859         struct in6_ifaddr *newia, *ia;
 1860         struct in6_aliasreq ifra;
 1861         int i, error;
 1862         int trylimit = 3;       /* XXX: adhoc value */
 1863         int updateflags;
 1864         u_int32_t randid[2];
 1865         time_t vltime0, pltime0;
 1866 
 1867         bzero(&ifra, sizeof(ifra));
 1868         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1869         ifra.ifra_addr = ia0->ia_addr;
 1870         /* copy prefix mask */
 1871         ifra.ifra_prefixmask = ia0->ia_prefixmask;
 1872         /* clear the old IFID */
 1873         for (i = 0; i < 4; i++) {
 1874                 ifra.ifra_addr.sin6_addr.s6_addr32[i] &=
 1875                     ifra.ifra_prefixmask.sin6_addr.s6_addr32[i];
 1876         }
 1877 
 1878   again:
 1879         if (in6_get_tmpifid(ifp, (u_int8_t *)randid,
 1880             (const u_int8_t *)&ia0->ia_addr.sin6_addr.s6_addr[8], forcegen)) {
 1881                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to find a good "
 1882                     "random IFID\n"));
 1883                 return (EINVAL);
 1884         }
 1885         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1886             (randid[0] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[2]));
 1887         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1888             (randid[1] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[3]));
 1889 
 1890         /*
 1891          * in6_get_tmpifid() quite likely provided a unique interface ID.
 1892          * However, we may still have a chance to see collision, because
 1893          * there may be a time lag between generation of the ID and generation
 1894          * of the address.  So, we'll do one more sanity check.
 1895          */
 1896         for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
 1897                 if (IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
 1898                     &ifra.ifra_addr.sin6_addr)) {
 1899                         if (trylimit-- == 0) {
 1900                                 /*
 1901                                  * Give up.  Something strange should have
 1902                                  * happened.
 1903                                  */
 1904                                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to "
 1905                                     "find a unique random IFID\n"));
 1906                                 return (EEXIST);
 1907                         }
 1908                         forcegen = 1;
 1909                         goto again;
 1910                 }
 1911         }
 1912 
 1913         /*
 1914          * The Valid Lifetime is the lower of the Valid Lifetime of the
 1915          * public address or TEMP_VALID_LIFETIME.
 1916          * The Preferred Lifetime is the lower of the Preferred Lifetime
 1917          * of the public address or TEMP_PREFERRED_LIFETIME -
 1918          * DESYNC_FACTOR.
 1919          */
 1920         if (ia0->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
 1921                 vltime0 = IFA6_IS_INVALID(ia0) ? 0 :
 1922                     (ia0->ia6_lifetime.ia6t_vltime -
 1923                     (time_second - ia0->ia6_updatetime));
 1924                 if (vltime0 > ip6_temp_valid_lifetime)
 1925                         vltime0 = ip6_temp_valid_lifetime;
 1926         } else
 1927                 vltime0 = ip6_temp_valid_lifetime;
 1928         if (ia0->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
 1929                 pltime0 = IFA6_IS_DEPRECATED(ia0) ? 0 :
 1930                     (ia0->ia6_lifetime.ia6t_pltime -
 1931                     (time_second - ia0->ia6_updatetime));
 1932                 if (pltime0 > ip6_temp_preferred_lifetime - ip6_desync_factor){
 1933                         pltime0 = ip6_temp_preferred_lifetime -
 1934                             ip6_desync_factor;
 1935                 }
 1936         } else
 1937                 pltime0 = ip6_temp_preferred_lifetime - ip6_desync_factor;
 1938         ifra.ifra_lifetime.ia6t_vltime = vltime0;
 1939         ifra.ifra_lifetime.ia6t_pltime = pltime0;
 1940 
 1941         /*
 1942          * A temporary address is created only if this calculated Preferred
 1943          * Lifetime is greater than REGEN_ADVANCE time units.
 1944          */
 1945         if (ifra.ifra_lifetime.ia6t_pltime <= ip6_temp_regen_advance)
 1946                 return (0);
 1947 
 1948         /* XXX: scope zone ID? */
 1949 
 1950         ifra.ifra_flags |= (IN6_IFF_AUTOCONF|IN6_IFF_TEMPORARY);
 1951 
 1952         /* allocate ifaddr structure, link into chain, etc. */
 1953         updateflags = 0;
 1954         if (delay)
 1955                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1956         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0)
 1957                 return (error);
 1958 
 1959         newia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1960         if (newia == NULL) {    /* XXX: can it happen? */
 1961                 nd6log((LOG_ERR,
 1962                     "in6_tmpifadd: ifa update succeeded, but we got "
 1963                     "no ifaddr\n"));
 1964                 return (EINVAL); /* XXX */
 1965         }
 1966         newia->ia6_ndpr = ia0->ia6_ndpr;
 1967         newia->ia6_ndpr->ndpr_refcnt++;
 1968 
 1969         /*
 1970          * A newly added address might affect the status of other addresses.
 1971          * XXX: when the temporary address is generated with a new public
 1972          * address, the onlink check is redundant.  However, it would be safe
 1973          * to do the check explicitly everywhere a new address is generated,
 1974          * and, in fact, we surely need the check when we create a new
 1975          * temporary address due to deprecation of an old temporary address.
 1976          */
 1977         pfxlist_onlink_check();
 1978 
 1979         return (0);
 1980 }
 1981 
 1982 static int
 1983 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
 1984 {
 1985         if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
 1986                 ndpr->ndpr_preferred = 0;
 1987         else
 1988                 ndpr->ndpr_preferred = time_second + ndpr->ndpr_pltime;
 1989         if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
 1990                 ndpr->ndpr_expire = 0;
 1991         else
 1992                 ndpr->ndpr_expire = time_second + ndpr->ndpr_vltime;
 1993 
 1994         return 0;
 1995 }
 1996 
 1997 static void
 1998 in6_init_address_ltimes(struct nd_prefix *new, struct in6_addrlifetime *lt6)
 1999 {
 2000         /* init ia6t_expire */
 2001         if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
 2002                 lt6->ia6t_expire = 0;
 2003         else {
 2004                 lt6->ia6t_expire = time_second;
 2005                 lt6->ia6t_expire += lt6->ia6t_vltime;
 2006         }
 2007 
 2008         /* init ia6t_preferred */
 2009         if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
 2010                 lt6->ia6t_preferred = 0;
 2011         else {
 2012                 lt6->ia6t_preferred = time_second;
 2013                 lt6->ia6t_preferred += lt6->ia6t_pltime;
 2014         }
 2015 }
 2016 
 2017 /*
 2018  * Delete all the routing table entries that use the specified gateway.
 2019  * XXX: this function causes search through all entries of routing table, so
 2020  * it shouldn't be called when acting as a router.
 2021  */
 2022 void
 2023 rt6_flush(struct in6_addr *gateway, struct ifnet *ifp)
 2024 {
 2025 
 2026         struct radix_node_head *rnh = rt_tables[0][AF_INET6];
 2027         int s = splnet();
 2028 
 2029         /* We'll care only link-local addresses */
 2030         if (!IN6_IS_ADDR_LINKLOCAL(gateway)) {
 2031                 splx(s);
 2032                 return;
 2033         }
 2034 
 2035         RADIX_NODE_HEAD_LOCK(rnh);
 2036         rnh->rnh_walktree(rnh, rt6_deleteroute, (void *)gateway);
 2037         RADIX_NODE_HEAD_UNLOCK(rnh);
 2038         splx(s);
 2039 }
 2040 
 2041 static int
 2042 rt6_deleteroute(struct radix_node *rn, void *arg)
 2043 {
 2044 #define SIN6(s) ((struct sockaddr_in6 *)s)
 2045         struct rtentry *rt = (struct rtentry *)rn;
 2046         struct in6_addr *gate = (struct in6_addr *)arg;
 2047 
 2048         if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
 2049                 return (0);
 2050 
 2051         if (!IN6_ARE_ADDR_EQUAL(gate, &SIN6(rt->rt_gateway)->sin6_addr)) {
 2052                 return (0);
 2053         }
 2054 
 2055         /*
 2056          * Do not delete a static route.
 2057          * XXX: this seems to be a bit ad-hoc. Should we consider the
 2058          * 'cloned' bit instead?
 2059          */
 2060         if ((rt->rt_flags & RTF_STATIC) != 0)
 2061                 return (0);
 2062 
 2063         /*
 2064          * We delete only host route. This means, in particular, we don't
 2065          * delete default route.
 2066          */
 2067         if ((rt->rt_flags & RTF_HOST) == 0)
 2068                 return (0);
 2069 
 2070         return (rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
 2071             rt_mask(rt), rt->rt_flags, 0));
 2072 #undef SIN6
 2073 }
 2074 
 2075 int
 2076 nd6_setdefaultiface(int ifindex)
 2077 {
 2078         int error = 0;
 2079 
 2080         if (ifindex < 0 || if_index < ifindex)
 2081                 return (EINVAL);
 2082         if (ifindex != 0 && !ifnet_byindex(ifindex))
 2083                 return (EINVAL);
 2084 
 2085         if (nd6_defifindex != ifindex) {
 2086                 nd6_defifindex = ifindex;
 2087                 if (nd6_defifindex > 0)
 2088                         nd6_defifp = ifnet_byindex(nd6_defifindex);
 2089                 else
 2090                         nd6_defifp = NULL;
 2091 
 2092                 /*
 2093                  * Our current implementation assumes one-to-one maping between
 2094                  * interfaces and links, so it would be natural to use the
 2095                  * default interface as the default link.
 2096                  */
 2097                 scope6_setdefault(nd6_defifp);
 2098         }
 2099 
 2100         return (error);
 2101 }

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