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/9.2/sys/netinet6/nd6_rtr.c 244524 2012-12-21 00:41:52Z delphij $");
   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(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(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(struct nd_prefix *,
   85         struct in6_addrlifetime *);
   86 
   87 static int nd6_prefix_onlink(struct nd_prefix *);
   88 static int nd6_prefix_offlink(struct nd_prefix *);
   89 
   90 static int rt6_deleteroute(struct radix_node *, void *);
   91 
   92 VNET_DECLARE(int, nd6_recalc_reachtm_interval);
   93 #define V_nd6_recalc_reachtm_interval   VNET(nd6_recalc_reachtm_interval)
   94 
   95 static VNET_DEFINE(struct ifnet *, nd6_defifp);
   96 VNET_DEFINE(int, nd6_defifindex);
   97 #define V_nd6_defifp                    VNET(nd6_defifp)
   98 
   99 VNET_DEFINE(int, ip6_use_tempaddr) = 0;
  100 
  101 VNET_DEFINE(int, ip6_desync_factor);
  102 VNET_DEFINE(u_int32_t, ip6_temp_preferred_lifetime) = DEF_TEMP_PREFERRED_LIFETIME;
  103 VNET_DEFINE(u_int32_t, ip6_temp_valid_lifetime) = DEF_TEMP_VALID_LIFETIME;
  104 
  105 VNET_DEFINE(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         /*
  134          * Accept RS only when V_ip6_forwarding=1 and the interface has
  135          * no ND6_IFF_ACCEPT_RTADV.
  136          */
  137         if (!V_ip6_forwarding || ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV)
  138                 goto freeit;
  139 
  140         /* Sanity checks */
  141         if (ip6->ip6_hlim != 255) {
  142                 nd6log((LOG_ERR,
  143                     "nd6_rs_input: invalid hlim (%d) from %s to %s on %s\n",
  144                     ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  145                     ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
  146                 goto bad;
  147         }
  148 
  149         /*
  150          * Don't update the neighbor cache, if src = ::.
  151          * This indicates that the src has no IP address assigned yet.
  152          */
  153         if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
  154                 goto freeit;
  155 
  156 #ifndef PULLDOWN_TEST
  157         IP6_EXTHDR_CHECK(m, off, icmp6len,);
  158         nd_rs = (struct nd_router_solicit *)((caddr_t)ip6 + off);
  159 #else
  160         IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
  161         if (nd_rs == NULL) {
  162                 ICMP6STAT_INC(icp6s_tooshort);
  163                 return;
  164         }
  165 #endif
  166 
  167         icmp6len -= sizeof(*nd_rs);
  168         nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
  169         if (nd6_options(&ndopts) < 0) {
  170                 nd6log((LOG_INFO,
  171                     "nd6_rs_input: invalid ND option, ignored\n"));
  172                 /* nd6_options have incremented stats */
  173                 goto freeit;
  174         }
  175 
  176         if (ndopts.nd_opts_src_lladdr) {
  177                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  178                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  179         }
  180 
  181         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  182                 nd6log((LOG_INFO,
  183                     "nd6_rs_input: lladdrlen mismatch for %s "
  184                     "(if %d, RS packet %d)\n",
  185                     ip6_sprintf(ip6bufs, &saddr6),
  186                     ifp->if_addrlen, lladdrlen - 2));
  187                 goto bad;
  188         }
  189 
  190         nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
  191 
  192  freeit:
  193         m_freem(m);
  194         return;
  195 
  196  bad:
  197         ICMP6STAT_INC(icp6s_badrs);
  198         m_freem(m);
  199 }
  200 
  201 /*
  202  * Receive Router Advertisement Message.
  203  *
  204  * Based on RFC 2461
  205  * TODO: on-link bit on prefix information
  206  * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
  207  */
  208 void
  209 nd6_ra_input(struct mbuf *m, int off, int icmp6len)
  210 {
  211         struct ifnet *ifp = m->m_pkthdr.rcvif;
  212         struct nd_ifinfo *ndi = ND_IFINFO(ifp);
  213         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  214         struct nd_router_advert *nd_ra;
  215         struct in6_addr saddr6 = ip6->ip6_src;
  216         int mcast = 0;
  217         union nd_opts ndopts;
  218         struct nd_defrouter *dr;
  219         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  220 
  221         /*
  222          * We only accept RAs only when the per-interface flag
  223          * ND6_IFF_ACCEPT_RTADV is on the receiving interface.
  224          */
  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_INC(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         /*
  275          * Effectively-disable routes from RA messages when
  276          * ND6_IFF_NO_RADR enabled on the receiving interface or
  277          * (ip6.forwarding == 1 && ip6.rfc6204w3 != 1).
  278          */
  279         if (ndi->flags & ND6_IFF_NO_RADR)
  280                 dr0.rtlifetime = 0;
  281         else if (V_ip6_forwarding && !V_ip6_rfc6204w3)
  282                 dr0.rtlifetime = 0;
  283         else
  284                 dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
  285         dr0.expire = time_second + dr0.rtlifetime;
  286         dr0.ifp = ifp;
  287         /* unspecified or not? (RFC 2461 6.3.4) */
  288         if (advreachable) {
  289                 advreachable = ntohl(advreachable);
  290                 if (advreachable <= MAX_REACHABLE_TIME &&
  291                     ndi->basereachable != advreachable) {
  292                         ndi->basereachable = advreachable;
  293                         ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
  294                         ndi->recalctm = V_nd6_recalc_reachtm_interval; /* reset */
  295                 }
  296         }
  297         if (nd_ra->nd_ra_retransmit)
  298                 ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
  299         if (nd_ra->nd_ra_curhoplimit)
  300                 ndi->chlim = nd_ra->nd_ra_curhoplimit;
  301         dr = defrtrlist_update(&dr0);
  302     }
  303 
  304         /*
  305          * prefix
  306          */
  307         if (ndopts.nd_opts_pi) {
  308                 struct nd_opt_hdr *pt;
  309                 struct nd_opt_prefix_info *pi = NULL;
  310                 struct nd_prefixctl pr;
  311 
  312                 for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
  313                      pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
  314                      pt = (struct nd_opt_hdr *)((caddr_t)pt +
  315                                                 (pt->nd_opt_len << 3))) {
  316                         if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
  317                                 continue;
  318                         pi = (struct nd_opt_prefix_info *)pt;
  319 
  320                         if (pi->nd_opt_pi_len != 4) {
  321                                 nd6log((LOG_INFO,
  322                                     "nd6_ra_input: invalid option "
  323                                     "len %d for prefix information option, "
  324                                     "ignored\n", pi->nd_opt_pi_len));
  325                                 continue;
  326                         }
  327 
  328                         if (128 < pi->nd_opt_pi_prefix_len) {
  329                                 nd6log((LOG_INFO,
  330                                     "nd6_ra_input: invalid prefix "
  331                                     "len %d for prefix information option, "
  332                                     "ignored\n", pi->nd_opt_pi_prefix_len));
  333                                 continue;
  334                         }
  335 
  336                         if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
  337                          || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
  338                                 nd6log((LOG_INFO,
  339                                     "nd6_ra_input: invalid prefix "
  340                                     "%s, ignored\n",
  341                                     ip6_sprintf(ip6bufs,
  342                                         &pi->nd_opt_pi_prefix)));
  343                                 continue;
  344                         }
  345 
  346                         bzero(&pr, sizeof(pr));
  347                         pr.ndpr_prefix.sin6_family = AF_INET6;
  348                         pr.ndpr_prefix.sin6_len = sizeof(pr.ndpr_prefix);
  349                         pr.ndpr_prefix.sin6_addr = pi->nd_opt_pi_prefix;
  350                         pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;
  351 
  352                         pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
  353                             ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
  354                         pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
  355                             ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
  356                         pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
  357                         pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
  358                         pr.ndpr_pltime = ntohl(pi->nd_opt_pi_preferred_time);
  359                         (void)prelist_update(&pr, dr, m, mcast);
  360                 }
  361         }
  362 
  363         /*
  364          * MTU
  365          */
  366         if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
  367                 u_long mtu;
  368                 u_long maxmtu;
  369 
  370                 mtu = (u_long)ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
  371 
  372                 /* lower bound */
  373                 if (mtu < IPV6_MMTU) {
  374                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
  375                             "mtu=%lu sent from %s, ignoring\n",
  376                             mtu, ip6_sprintf(ip6bufs, &ip6->ip6_src)));
  377                         goto skip;
  378                 }
  379 
  380                 /* upper bound */
  381                 maxmtu = (ndi->maxmtu && ndi->maxmtu < ifp->if_mtu)
  382                     ? ndi->maxmtu : ifp->if_mtu;
  383                 if (mtu <= maxmtu) {
  384                         int change = (ndi->linkmtu != mtu);
  385 
  386                         ndi->linkmtu = mtu;
  387                         if (change) /* in6_maxmtu may change */
  388                                 in6_setmaxmtu();
  389                 } else {
  390                         nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
  391                             "mtu=%lu sent from %s; "
  392                             "exceeds maxmtu %lu, ignoring\n",
  393                             mtu, ip6_sprintf(ip6bufs, &ip6->ip6_src), maxmtu));
  394                 }
  395         }
  396 
  397  skip:
  398 
  399         /*
  400          * Source link layer address
  401          */
  402     {
  403         char *lladdr = NULL;
  404         int lladdrlen = 0;
  405 
  406         if (ndopts.nd_opts_src_lladdr) {
  407                 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
  408                 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
  409         }
  410 
  411         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  412                 nd6log((LOG_INFO,
  413                     "nd6_ra_input: lladdrlen mismatch for %s "
  414                     "(if %d, RA packet %d)\n", ip6_sprintf(ip6bufs, &saddr6),
  415                     ifp->if_addrlen, lladdrlen - 2));
  416                 goto bad;
  417         }
  418 
  419         nd6_cache_lladdr(ifp, &saddr6, lladdr,
  420             lladdrlen, ND_ROUTER_ADVERT, 0);
  421 
  422         /*
  423          * Installing a link-layer address might change the state of the
  424          * router's neighbor cache, which might also affect our on-link
  425          * detection of adveritsed prefixes.
  426          */
  427         pfxlist_onlink_check();
  428     }
  429 
  430  freeit:
  431         m_freem(m);
  432         return;
  433 
  434  bad:
  435         ICMP6STAT_INC(icp6s_badra);
  436         m_freem(m);
  437 }
  438 
  439 /*
  440  * default router list proccessing sub routines
  441  */
  442 
  443 /* tell the change to user processes watching the routing socket. */
  444 static void
  445 nd6_rtmsg(int cmd, struct rtentry *rt)
  446 {
  447         struct rt_addrinfo info;
  448         struct ifnet *ifp;
  449         struct ifaddr *ifa;
  450 
  451         bzero((caddr_t)&info, sizeof(info));
  452         info.rti_info[RTAX_DST] = rt_key(rt);
  453         info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
  454         info.rti_info[RTAX_NETMASK] = rt_mask(rt);
  455         ifp = rt->rt_ifp;
  456         if (ifp != NULL) {
  457                 IF_ADDR_RLOCK(ifp);
  458                 ifa = TAILQ_FIRST(&ifp->if_addrhead);
  459                 info.rti_info[RTAX_IFP] = ifa->ifa_addr;
  460                 ifa_ref(ifa);
  461                 IF_ADDR_RUNLOCK(ifp);
  462                 info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
  463         } else
  464                 ifa = NULL;
  465 
  466         rt_missmsg_fib(cmd, &info, rt->rt_flags, 0, rt->rt_fibnum);
  467         if (ifa != NULL)
  468                 ifa_free(ifa);
  469 }
  470 
  471 static void
  472 defrouter_addreq(struct nd_defrouter *new)
  473 {
  474         struct sockaddr_in6 def, mask, gate;
  475         struct rtentry *newrt = NULL;
  476         int s;
  477         int error;
  478 
  479         bzero(&def, sizeof(def));
  480         bzero(&mask, sizeof(mask));
  481         bzero(&gate, sizeof(gate));
  482 
  483         def.sin6_len = mask.sin6_len = gate.sin6_len =
  484             sizeof(struct sockaddr_in6);
  485         def.sin6_family = gate.sin6_family = AF_INET6;
  486         gate.sin6_addr = new->rtaddr;
  487 
  488         s = splnet();
  489         error = in6_rtrequest(RTM_ADD, (struct sockaddr *)&def,
  490             (struct sockaddr *)&gate, (struct sockaddr *)&mask,
  491             RTF_GATEWAY, &newrt, RT_DEFAULT_FIB);
  492         if (newrt) {
  493                 nd6_rtmsg(RTM_ADD, newrt); /* tell user process */
  494                 RTFREE(newrt);
  495         }
  496         if (error == 0)
  497                 new->installed = 1;
  498         splx(s);
  499         return;
  500 }
  501 
  502 struct nd_defrouter *
  503 defrouter_lookup(struct in6_addr *addr, struct ifnet *ifp)
  504 {
  505         struct nd_defrouter *dr;
  506 
  507         TAILQ_FOREACH(dr, &V_nd_defrouter, dr_entry) {
  508                 if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr))
  509                         return (dr);
  510         }
  511 
  512         return (NULL);          /* search failed */
  513 }
  514 
  515 /*
  516  * Remove the default route for a given router.
  517  * This is just a subroutine function for defrouter_select(), and should
  518  * not be called from anywhere else.
  519  */
  520 static void
  521 defrouter_delreq(struct nd_defrouter *dr)
  522 {
  523         struct sockaddr_in6 def, mask, gate;
  524         struct rtentry *oldrt = NULL;
  525 
  526         bzero(&def, sizeof(def));
  527         bzero(&mask, sizeof(mask));
  528         bzero(&gate, sizeof(gate));
  529 
  530         def.sin6_len = mask.sin6_len = gate.sin6_len =
  531             sizeof(struct sockaddr_in6);
  532         def.sin6_family = gate.sin6_family = AF_INET6;
  533         gate.sin6_addr = dr->rtaddr;
  534 
  535         in6_rtrequest(RTM_DELETE, (struct sockaddr *)&def,
  536             (struct sockaddr *)&gate,
  537             (struct sockaddr *)&mask, RTF_GATEWAY, &oldrt, RT_DEFAULT_FIB);
  538         if (oldrt) {
  539                 nd6_rtmsg(RTM_DELETE, oldrt);
  540                 RTFREE(oldrt);
  541         }
  542 
  543         dr->installed = 0;
  544 }
  545 
  546 /*
  547  * remove all default routes from default router list
  548  */
  549 void
  550 defrouter_reset(void)
  551 {
  552         struct nd_defrouter *dr;
  553 
  554         TAILQ_FOREACH(dr, &V_nd_defrouter, dr_entry)
  555                 defrouter_delreq(dr);
  556 
  557         /*
  558          * XXX should we also nuke any default routers in the kernel, by
  559          * going through them by rtalloc1()?
  560          */
  561 }
  562 
  563 void
  564 defrtrlist_del(struct nd_defrouter *dr)
  565 {
  566         struct nd_defrouter *deldr = NULL;
  567         struct nd_prefix *pr;
  568 
  569         /*
  570          * Flush all the routing table entries that use the router
  571          * as a next hop.
  572          */
  573         if (ND_IFINFO(dr->ifp)->flags & ND6_IFF_ACCEPT_RTADV)
  574                 rt6_flush(&dr->rtaddr, dr->ifp);
  575 
  576         if (dr->installed) {
  577                 deldr = dr;
  578                 defrouter_delreq(dr);
  579         }
  580         TAILQ_REMOVE(&V_nd_defrouter, dr, dr_entry);
  581 
  582         /*
  583          * Also delete all the pointers to the router in each prefix lists.
  584          */
  585         LIST_FOREACH(pr, &V_nd_prefix, ndpr_entry) {
  586                 struct nd_pfxrouter *pfxrtr;
  587                 if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
  588                         pfxrtr_del(pfxrtr);
  589         }
  590         pfxlist_onlink_check();
  591 
  592         /*
  593          * If the router is the primary one, choose a new one.
  594          * Note that defrouter_select() will remove the current gateway
  595          * from the routing table.
  596          */
  597         if (deldr)
  598                 defrouter_select();
  599 
  600         free(dr, M_IP6NDP);
  601 }
  602 
  603 /*
  604  * Default Router Selection according to Section 6.3.6 of RFC 2461 and
  605  * draft-ietf-ipngwg-router-selection:
  606  * 1) Routers that are reachable or probably reachable should be preferred.
  607  *    If we have more than one (probably) reachable router, prefer ones
  608  *    with the highest router preference.
  609  * 2) When no routers on the list are known to be reachable or
  610  *    probably reachable, routers SHOULD be selected in a round-robin
  611  *    fashion, regardless of router preference values.
  612  * 3) If the Default Router List is empty, assume that all
  613  *    destinations are on-link.
  614  *
  615  * We assume nd_defrouter is sorted by router preference value.
  616  * Since the code below covers both with and without router preference cases,
  617  * we do not need to classify the cases by ifdef.
  618  *
  619  * At this moment, we do not try to install more than one default router,
  620  * even when the multipath routing is available, because we're not sure about
  621  * the benefits for stub hosts comparing to the risk of making the code
  622  * complicated and the possibility of introducing bugs.
  623  */
  624 void
  625 defrouter_select(void)
  626 {
  627         int s = splnet();
  628         struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
  629         struct llentry *ln = NULL;
  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_EMPTY(&V_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         TAILQ_FOREACH(dr, &V_nd_defrouter, dr_entry) {
  646                 IF_AFDATA_RLOCK(dr->ifp);
  647                 if (selected_dr == NULL &&
  648                     (ln = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) &&
  649                     ND6_IS_LLINFO_PROBREACH(ln)) {
  650                         selected_dr = dr;
  651                 }
  652                 IF_AFDATA_RUNLOCK(dr->ifp);
  653                 if (ln != NULL) {
  654                         LLE_RUNLOCK(ln);
  655                         ln = NULL;
  656                 }
  657 
  658                 if (dr->installed && installed_dr == NULL)
  659                         installed_dr = dr;
  660                 else if (dr->installed && installed_dr) {
  661                         /* this should not happen.  warn for diagnosis. */
  662                         log(LOG_ERR, "defrouter_select: more than one router"
  663                             " is installed\n");
  664                 }
  665         }
  666         /*
  667          * If none of the default routers was found to be reachable,
  668          * round-robin the list regardless of preference.
  669          * Otherwise, if we have an installed router, check if the selected
  670          * (reachable) router should really be preferred to the installed one.
  671          * We only prefer the new router when the old one is not reachable
  672          * or when the new one has a really higher preference value.
  673          */
  674         if (selected_dr == NULL) {
  675                 if (installed_dr == NULL || !TAILQ_NEXT(installed_dr, dr_entry))
  676                         selected_dr = TAILQ_FIRST(&V_nd_defrouter);
  677                 else
  678                         selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
  679         } else if (installed_dr) {
  680                 IF_AFDATA_RLOCK(installed_dr->ifp);
  681                 if ((ln = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp)) &&
  682                     ND6_IS_LLINFO_PROBREACH(ln) &&
  683                     rtpref(selected_dr) <= rtpref(installed_dr)) {
  684                         selected_dr = installed_dr;
  685                 }
  686                 IF_AFDATA_RUNLOCK(installed_dr->ifp);
  687                 if (ln != NULL)
  688                         LLE_RUNLOCK(ln);
  689         }
  690 
  691         /*
  692          * If the selected router is different than the installed one,
  693          * remove the installed router and install the selected one.
  694          * Note that the selected router is never NULL here.
  695          */
  696         if (installed_dr != selected_dr) {
  697                 if (installed_dr)
  698                         defrouter_delreq(installed_dr);
  699                 defrouter_addreq(selected_dr);
  700         }
  701 
  702         splx(s);
  703         return;
  704 }
  705 
  706 /*
  707  * for default router selection
  708  * regards router-preference field as a 2-bit signed integer
  709  */
  710 static int
  711 rtpref(struct nd_defrouter *dr)
  712 {
  713         switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
  714         case ND_RA_FLAG_RTPREF_HIGH:
  715                 return (RTPREF_HIGH);
  716         case ND_RA_FLAG_RTPREF_MEDIUM:
  717         case ND_RA_FLAG_RTPREF_RSV:
  718                 return (RTPREF_MEDIUM);
  719         case ND_RA_FLAG_RTPREF_LOW:
  720                 return (RTPREF_LOW);
  721         default:
  722                 /*
  723                  * This case should never happen.  If it did, it would mean a
  724                  * serious bug of kernel internal.  We thus always bark here.
  725                  * Or, can we even panic?
  726                  */
  727                 log(LOG_ERR, "rtpref: impossible RA flag %x\n", dr->flags);
  728                 return (RTPREF_INVALID);
  729         }
  730         /* NOTREACHED */
  731 }
  732 
  733 static struct nd_defrouter *
  734 defrtrlist_update(struct nd_defrouter *new)
  735 {
  736         struct nd_defrouter *dr, *n;
  737         int s = splnet();
  738 
  739         if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
  740                 /* entry exists */
  741                 if (new->rtlifetime == 0) {
  742                         defrtrlist_del(dr);
  743                         dr = NULL;
  744                 } else {
  745                         int oldpref = rtpref(dr);
  746 
  747                         /* override */
  748                         dr->flags = new->flags; /* xxx flag check */
  749                         dr->rtlifetime = new->rtlifetime;
  750                         dr->expire = new->expire;
  751 
  752                         /*
  753                          * If the preference does not change, there's no need
  754                          * to sort the entries. Also make sure the selected
  755                          * router is still installed in the kernel.
  756                          */
  757                         if (dr->installed && rtpref(new) == oldpref) {
  758                                 splx(s);
  759                                 return (dr);
  760                         }
  761 
  762                         /*
  763                          * preferred router may be changed, so relocate
  764                          * this router.
  765                          * XXX: calling TAILQ_REMOVE directly is a bad manner.
  766                          * However, since defrtrlist_del() has many side
  767                          * effects, we intentionally do so here.
  768                          * defrouter_select() below will handle routing
  769                          * changes later.
  770                          */
  771                         TAILQ_REMOVE(&V_nd_defrouter, dr, dr_entry);
  772                         n = dr;
  773                         goto insert;
  774                 }
  775                 splx(s);
  776                 return (dr);
  777         }
  778 
  779         /* entry does not exist */
  780         if (new->rtlifetime == 0) {
  781                 splx(s);
  782                 return (NULL);
  783         }
  784 
  785         n = (struct nd_defrouter *)malloc(sizeof(*n), M_IP6NDP, M_NOWAIT);
  786         if (n == NULL) {
  787                 splx(s);
  788                 return (NULL);
  789         }
  790         bzero(n, sizeof(*n));
  791         *n = *new;
  792 
  793 insert:
  794         /*
  795          * Insert the new router in the Default Router List;
  796          * The Default Router List should be in the descending order
  797          * of router-preferece.  Routers with the same preference are
  798          * sorted in the arriving time order.
  799          */
  800 
  801         /* insert at the end of the group */
  802         TAILQ_FOREACH(dr, &V_nd_defrouter, dr_entry) {
  803                 if (rtpref(n) > rtpref(dr))
  804                         break;
  805         }
  806         if (dr)
  807                 TAILQ_INSERT_BEFORE(dr, n, dr_entry);
  808         else
  809                 TAILQ_INSERT_TAIL(&V_nd_defrouter, n, dr_entry);
  810 
  811         defrouter_select();
  812 
  813         splx(s);
  814 
  815         return (n);
  816 }
  817 
  818 static struct nd_pfxrouter *
  819 pfxrtr_lookup(struct nd_prefix *pr, struct nd_defrouter *dr)
  820 {
  821         struct nd_pfxrouter *search;
  822 
  823         LIST_FOREACH(search, &pr->ndpr_advrtrs, pfr_entry) {
  824                 if (search->router == dr)
  825                         break;
  826         }
  827 
  828         return (search);
  829 }
  830 
  831 static void
  832 pfxrtr_add(struct nd_prefix *pr, struct nd_defrouter *dr)
  833 {
  834         struct nd_pfxrouter *new;
  835 
  836         new = (struct nd_pfxrouter *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  837         if (new == NULL)
  838                 return;
  839         bzero(new, sizeof(*new));
  840         new->router = dr;
  841 
  842         LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
  843 
  844         pfxlist_onlink_check();
  845 }
  846 
  847 static void
  848 pfxrtr_del(struct nd_pfxrouter *pfr)
  849 {
  850         LIST_REMOVE(pfr, pfr_entry);
  851         free(pfr, M_IP6NDP);
  852 }
  853 
  854 struct nd_prefix *
  855 nd6_prefix_lookup(struct nd_prefixctl *key)
  856 {
  857         struct nd_prefix *search;
  858 
  859         LIST_FOREACH(search, &V_nd_prefix, ndpr_entry) {
  860                 if (key->ndpr_ifp == search->ndpr_ifp &&
  861                     key->ndpr_plen == search->ndpr_plen &&
  862                     in6_are_prefix_equal(&key->ndpr_prefix.sin6_addr,
  863                     &search->ndpr_prefix.sin6_addr, key->ndpr_plen)) {
  864                         break;
  865                 }
  866         }
  867 
  868         return (search);
  869 }
  870 
  871 int
  872 nd6_prelist_add(struct nd_prefixctl *pr, struct nd_defrouter *dr,
  873     struct nd_prefix **newp)
  874 {
  875         struct nd_prefix *new = NULL;
  876         int error = 0;
  877         int i, s;
  878         char ip6buf[INET6_ADDRSTRLEN];
  879 
  880         new = (struct nd_prefix *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
  881         if (new == NULL)
  882                 return(ENOMEM);
  883         bzero(new, sizeof(*new));
  884         new->ndpr_ifp = pr->ndpr_ifp;
  885         new->ndpr_prefix = pr->ndpr_prefix;
  886         new->ndpr_plen = pr->ndpr_plen;
  887         new->ndpr_vltime = pr->ndpr_vltime;
  888         new->ndpr_pltime = pr->ndpr_pltime;
  889         new->ndpr_flags = pr->ndpr_flags;
  890         if ((error = in6_init_prefix_ltimes(new)) != 0) {
  891                 free(new, M_IP6NDP);
  892                 return(error);
  893         }
  894         new->ndpr_lastupdate = time_second;
  895         if (newp != NULL)
  896                 *newp = new;
  897 
  898         /* initialization */
  899         LIST_INIT(&new->ndpr_advrtrs);
  900         in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
  901         /* make prefix in the canonical form */
  902         for (i = 0; i < 4; i++)
  903                 new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
  904                     new->ndpr_mask.s6_addr32[i];
  905 
  906         s = splnet();
  907         /* link ndpr_entry to nd_prefix list */
  908         LIST_INSERT_HEAD(&V_nd_prefix, new, ndpr_entry);
  909         splx(s);
  910 
  911         /* ND_OPT_PI_FLAG_ONLINK processing */
  912         if (new->ndpr_raf_onlink) {
  913                 int e;
  914 
  915                 if ((e = nd6_prefix_onlink(new)) != 0) {
  916                         nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
  917                             "the prefix %s/%d on-link on %s (errno=%d)\n",
  918                             ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
  919                             pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  920                         /* proceed anyway. XXX: is it correct? */
  921                 }
  922         }
  923 
  924         if (dr)
  925                 pfxrtr_add(new, dr);
  926 
  927         return 0;
  928 }
  929 
  930 void
  931 prelist_remove(struct nd_prefix *pr)
  932 {
  933         struct nd_pfxrouter *pfr, *next;
  934         int e, s;
  935         char ip6buf[INET6_ADDRSTRLEN];
  936 
  937         /* make sure to invalidate the prefix until it is really freed. */
  938         pr->ndpr_vltime = 0;
  939         pr->ndpr_pltime = 0;
  940 
  941         /*
  942          * Though these flags are now meaningless, we'd rather keep the value
  943          * of pr->ndpr_raf_onlink and pr->ndpr_raf_auto not to confuse users
  944          * when executing "ndp -p".
  945          */
  946 
  947         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
  948             (e = nd6_prefix_offlink(pr)) != 0) {
  949                 nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
  950                     "on %s, errno=%d\n",
  951                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
  952                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
  953                 /* what should we do? */
  954         }
  955 
  956         if (pr->ndpr_refcnt > 0)
  957                 return;         /* notice here? */
  958 
  959         s = splnet();
  960 
  961         /* unlink ndpr_entry from nd_prefix list */
  962         LIST_REMOVE(pr, ndpr_entry);
  963 
  964         /* free list of routers that adversed the prefix */
  965         LIST_FOREACH_SAFE(pfr, &pr->ndpr_advrtrs, pfr_entry, next) {
  966                 free(pfr, M_IP6NDP);
  967         }
  968         splx(s);
  969 
  970         free(pr, M_IP6NDP);
  971 
  972         pfxlist_onlink_check();
  973 }
  974 
  975 /*
  976  * dr - may be NULL
  977  */
  978 
  979 static int
  980 prelist_update(struct nd_prefixctl *new, struct nd_defrouter *dr,
  981     struct mbuf *m, int mcast)
  982 {
  983         struct in6_ifaddr *ia6 = NULL, *ia6_match = NULL;
  984         struct ifaddr *ifa;
  985         struct ifnet *ifp = new->ndpr_ifp;
  986         struct nd_prefix *pr;
  987         int s = splnet();
  988         int error = 0;
  989         int newprefix = 0;
  990         int auth;
  991         struct in6_addrlifetime lt6_tmp;
  992         char ip6buf[INET6_ADDRSTRLEN];
  993 
  994         auth = 0;
  995         if (m) {
  996                 /*
  997                  * Authenticity for NA consists authentication for
  998                  * both IP header and IP datagrams, doesn't it ?
  999                  */
 1000 #if defined(M_AUTHIPHDR) && defined(M_AUTHIPDGM)
 1001                 auth = ((m->m_flags & M_AUTHIPHDR) &&
 1002                     (m->m_flags & M_AUTHIPDGM));
 1003 #endif
 1004         }
 1005 
 1006         if ((pr = nd6_prefix_lookup(new)) != NULL) {
 1007                 /*
 1008                  * nd6_prefix_lookup() ensures that pr and new have the same
 1009                  * prefix on a same interface.
 1010                  */
 1011 
 1012                 /*
 1013                  * Update prefix information.  Note that the on-link (L) bit
 1014                  * and the autonomous (A) bit should NOT be changed from 1
 1015                  * to 0.
 1016                  */
 1017                 if (new->ndpr_raf_onlink == 1)
 1018                         pr->ndpr_raf_onlink = 1;
 1019                 if (new->ndpr_raf_auto == 1)
 1020                         pr->ndpr_raf_auto = 1;
 1021                 if (new->ndpr_raf_onlink) {
 1022                         pr->ndpr_vltime = new->ndpr_vltime;
 1023                         pr->ndpr_pltime = new->ndpr_pltime;
 1024                         (void)in6_init_prefix_ltimes(pr); /* XXX error case? */
 1025                         pr->ndpr_lastupdate = time_second;
 1026                 }
 1027 
 1028                 if (new->ndpr_raf_onlink &&
 1029                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1030                         int e;
 1031 
 1032                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1033                                 nd6log((LOG_ERR,
 1034                                     "prelist_update: failed to make "
 1035                                     "the prefix %s/%d on-link on %s "
 1036                                     "(errno=%d)\n",
 1037                                     ip6_sprintf(ip6buf,
 1038                                             &pr->ndpr_prefix.sin6_addr),
 1039                                     pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
 1040                                 /* proceed anyway. XXX: is it correct? */
 1041                         }
 1042                 }
 1043 
 1044                 if (dr && pfxrtr_lookup(pr, dr) == NULL)
 1045                         pfxrtr_add(pr, dr);
 1046         } else {
 1047                 struct nd_prefix *newpr = NULL;
 1048 
 1049                 newprefix = 1;
 1050 
 1051                 if (new->ndpr_vltime == 0)
 1052                         goto end;
 1053                 if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
 1054                         goto end;
 1055 
 1056                 error = nd6_prelist_add(new, dr, &newpr);
 1057                 if (error != 0 || newpr == NULL) {
 1058                         nd6log((LOG_NOTICE, "prelist_update: "
 1059                             "nd6_prelist_add failed for %s/%d on %s "
 1060                             "errno=%d, returnpr=%p\n",
 1061                             ip6_sprintf(ip6buf, &new->ndpr_prefix.sin6_addr),
 1062                             new->ndpr_plen, if_name(new->ndpr_ifp),
 1063                             error, newpr));
 1064                         goto end; /* we should just give up in this case. */
 1065                 }
 1066 
 1067                 /*
 1068                  * XXX: from the ND point of view, we can ignore a prefix
 1069                  * with the on-link bit being zero.  However, we need a
 1070                  * prefix structure for references from autoconfigured
 1071                  * addresses.  Thus, we explicitly make sure that the prefix
 1072                  * itself expires now.
 1073                  */
 1074                 if (newpr->ndpr_raf_onlink == 0) {
 1075                         newpr->ndpr_vltime = 0;
 1076                         newpr->ndpr_pltime = 0;
 1077                         in6_init_prefix_ltimes(newpr);
 1078                 }
 1079 
 1080                 pr = newpr;
 1081         }
 1082 
 1083         /*
 1084          * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
 1085          * Note that pr must be non NULL at this point.
 1086          */
 1087 
 1088         /* 5.5.3 (a). Ignore the prefix without the A bit set. */
 1089         if (!new->ndpr_raf_auto)
 1090                 goto end;
 1091 
 1092         /*
 1093          * 5.5.3 (b). the link-local prefix should have been ignored in
 1094          * nd6_ra_input.
 1095          */
 1096 
 1097         /* 5.5.3 (c). Consistency check on lifetimes: pltime <= vltime. */
 1098         if (new->ndpr_pltime > new->ndpr_vltime) {
 1099                 error = EINVAL; /* XXX: won't be used */
 1100                 goto end;
 1101         }
 1102 
 1103         /*
 1104          * 5.5.3 (d).  If the prefix advertised is not equal to the prefix of
 1105          * an address configured by stateless autoconfiguration already in the
 1106          * list of addresses associated with the interface, and the Valid
 1107          * Lifetime is not 0, form an address.  We first check if we have
 1108          * a matching prefix.
 1109          * Note: we apply a clarification in rfc2462bis-02 here.  We only
 1110          * consider autoconfigured addresses while RFC2462 simply said
 1111          * "address".
 1112          */
 1113         IF_ADDR_RLOCK(ifp);
 1114         TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 1115                 struct in6_ifaddr *ifa6;
 1116                 u_int32_t remaininglifetime;
 1117 
 1118                 if (ifa->ifa_addr->sa_family != AF_INET6)
 1119                         continue;
 1120 
 1121                 ifa6 = (struct in6_ifaddr *)ifa;
 1122 
 1123                 /*
 1124                  * We only consider autoconfigured addresses as per rfc2462bis.
 1125                  */
 1126                 if (!(ifa6->ia6_flags & IN6_IFF_AUTOCONF))
 1127                         continue;
 1128 
 1129                 /*
 1130                  * Spec is not clear here, but I believe we should concentrate
 1131                  * on unicast (i.e. not anycast) addresses.
 1132                  * XXX: other ia6_flags? detached or duplicated?
 1133                  */
 1134                 if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0)
 1135                         continue;
 1136 
 1137                 /*
 1138                  * Ignore the address if it is not associated with a prefix
 1139                  * or is associated with a prefix that is different from this
 1140                  * one.  (pr is never NULL here)
 1141                  */
 1142                 if (ifa6->ia6_ndpr != pr)
 1143                         continue;
 1144 
 1145                 if (ia6_match == NULL) /* remember the first one */
 1146                         ia6_match = ifa6;
 1147 
 1148                 /*
 1149                  * An already autoconfigured address matched.  Now that we
 1150                  * are sure there is at least one matched address, we can
 1151                  * proceed to 5.5.3. (e): update the lifetimes according to the
 1152                  * "two hours" rule and the privacy extension.
 1153                  * We apply some clarifications in rfc2462bis:
 1154                  * - use remaininglifetime instead of storedlifetime as a
 1155                  *   variable name
 1156                  * - remove the dead code in the "two-hour" rule
 1157                  */
 1158 #define TWOHOUR         (120*60)
 1159                 lt6_tmp = ifa6->ia6_lifetime;
 1160 
 1161                 if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME)
 1162                         remaininglifetime = ND6_INFINITE_LIFETIME;
 1163                 else if (time_second - ifa6->ia6_updatetime >
 1164                          lt6_tmp.ia6t_vltime) {
 1165                         /*
 1166                          * The case of "invalid" address.  We should usually
 1167                          * not see this case.
 1168                          */
 1169                         remaininglifetime = 0;
 1170                 } else
 1171                         remaininglifetime = lt6_tmp.ia6t_vltime -
 1172                             (time_second - ifa6->ia6_updatetime);
 1173 
 1174                 /* when not updating, keep the current stored lifetime. */
 1175                 lt6_tmp.ia6t_vltime = remaininglifetime;
 1176 
 1177                 if (TWOHOUR < new->ndpr_vltime ||
 1178                     remaininglifetime < new->ndpr_vltime) {
 1179                         lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1180                 } else if (remaininglifetime <= TWOHOUR) {
 1181                         if (auth) {
 1182                                 lt6_tmp.ia6t_vltime = new->ndpr_vltime;
 1183                         }
 1184                 } else {
 1185                         /*
 1186                          * new->ndpr_vltime <= TWOHOUR &&
 1187                          * TWOHOUR < remaininglifetime
 1188                          */
 1189                         lt6_tmp.ia6t_vltime = TWOHOUR;
 1190                 }
 1191 
 1192                 /* The 2 hour rule is not imposed for preferred lifetime. */
 1193                 lt6_tmp.ia6t_pltime = new->ndpr_pltime;
 1194 
 1195                 in6_init_address_ltimes(pr, &lt6_tmp);
 1196 
 1197                 /*
 1198                  * We need to treat lifetimes for temporary addresses
 1199                  * differently, according to
 1200                  * draft-ietf-ipv6-privacy-addrs-v2-01.txt 3.3 (1);
 1201                  * we only update the lifetimes when they are in the maximum
 1202                  * intervals.
 1203                  */
 1204                 if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0) {
 1205                         u_int32_t maxvltime, maxpltime;
 1206 
 1207                         if (V_ip6_temp_valid_lifetime >
 1208                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1209                             V_ip6_desync_factor)) {
 1210                                 maxvltime = V_ip6_temp_valid_lifetime -
 1211                                     (time_second - ifa6->ia6_createtime) -
 1212                                     V_ip6_desync_factor;
 1213                         } else
 1214                                 maxvltime = 0;
 1215                         if (V_ip6_temp_preferred_lifetime >
 1216                             (u_int32_t)((time_second - ifa6->ia6_createtime) +
 1217                             V_ip6_desync_factor)) {
 1218                                 maxpltime = V_ip6_temp_preferred_lifetime -
 1219                                     (time_second - ifa6->ia6_createtime) -
 1220                                     V_ip6_desync_factor;
 1221                         } else
 1222                                 maxpltime = 0;
 1223 
 1224                         if (lt6_tmp.ia6t_vltime == ND6_INFINITE_LIFETIME ||
 1225                             lt6_tmp.ia6t_vltime > maxvltime) {
 1226                                 lt6_tmp.ia6t_vltime = maxvltime;
 1227                         }
 1228                         if (lt6_tmp.ia6t_pltime == ND6_INFINITE_LIFETIME ||
 1229                             lt6_tmp.ia6t_pltime > maxpltime) {
 1230                                 lt6_tmp.ia6t_pltime = maxpltime;
 1231                         }
 1232                 }
 1233                 ifa6->ia6_lifetime = lt6_tmp;
 1234                 ifa6->ia6_updatetime = time_second;
 1235         }
 1236         IF_ADDR_RUNLOCK(ifp);
 1237         if (ia6_match == NULL && new->ndpr_vltime) {
 1238                 int ifidlen;
 1239 
 1240                 /*
 1241                  * 5.5.3 (d) (continued)
 1242                  * No address matched and the valid lifetime is non-zero.
 1243                  * Create a new address.
 1244                  */
 1245 
 1246                 /*
 1247                  * Prefix Length check:
 1248                  * If the sum of the prefix length and interface identifier
 1249                  * length does not equal 128 bits, the Prefix Information
 1250                  * option MUST be ignored.  The length of the interface
 1251                  * identifier is defined in a separate link-type specific
 1252                  * document.
 1253                  */
 1254                 ifidlen = in6_if2idlen(ifp);
 1255                 if (ifidlen < 0) {
 1256                         /* this should not happen, so we always log it. */
 1257                         log(LOG_ERR, "prelist_update: IFID undefined (%s)\n",
 1258                             if_name(ifp));
 1259                         goto end;
 1260                 }
 1261                 if (ifidlen + pr->ndpr_plen != 128) {
 1262                         nd6log((LOG_INFO,
 1263                             "prelist_update: invalid prefixlen "
 1264                             "%d for %s, ignored\n",
 1265                             pr->ndpr_plen, if_name(ifp)));
 1266                         goto end;
 1267                 }
 1268 
 1269                 if ((ia6 = in6_ifadd(new, mcast)) != NULL) {
 1270                         /*
 1271                          * note that we should use pr (not new) for reference.
 1272                          */
 1273                         pr->ndpr_refcnt++;
 1274                         ia6->ia6_ndpr = pr;
 1275 
 1276                         /*
 1277                          * RFC 3041 3.3 (2).
 1278                          * When a new public address is created as described
 1279                          * in RFC2462, also create a new temporary address.
 1280                          *
 1281                          * RFC 3041 3.5.
 1282                          * When an interface connects to a new link, a new
 1283                          * randomized interface identifier should be generated
 1284                          * immediately together with a new set of temporary
 1285                          * addresses.  Thus, we specifiy 1 as the 2nd arg of
 1286                          * in6_tmpifadd().
 1287                          */
 1288                         if (V_ip6_use_tempaddr) {
 1289                                 int e;
 1290                                 if ((e = in6_tmpifadd(ia6, 1, 1)) != 0) {
 1291                                         nd6log((LOG_NOTICE, "prelist_update: "
 1292                                             "failed to create a temporary "
 1293                                             "address, errno=%d\n",
 1294                                             e));
 1295                                 }
 1296                         }
 1297                         ifa_free(&ia6->ia_ifa);
 1298 
 1299                         /*
 1300                          * A newly added address might affect the status
 1301                          * of other addresses, so we check and update it.
 1302                          * XXX: what if address duplication happens?
 1303                          */
 1304                         pfxlist_onlink_check();
 1305                 } else {
 1306                         /* just set an error. do not bark here. */
 1307                         error = EADDRNOTAVAIL; /* XXX: might be unused. */
 1308                 }
 1309         }
 1310 
 1311  end:
 1312         splx(s);
 1313         return error;
 1314 }
 1315 
 1316 /*
 1317  * A supplement function used in the on-link detection below;
 1318  * detect if a given prefix has a (probably) reachable advertising router.
 1319  * XXX: lengthy function name...
 1320  */
 1321 static struct nd_pfxrouter *
 1322 find_pfxlist_reachable_router(struct nd_prefix *pr)
 1323 {
 1324         struct nd_pfxrouter *pfxrtr;
 1325         struct llentry *ln;
 1326         int canreach;
 1327 
 1328         LIST_FOREACH(pfxrtr, &pr->ndpr_advrtrs, pfr_entry) {
 1329                 IF_AFDATA_RLOCK(pfxrtr->router->ifp);
 1330                 ln = nd6_lookup(&pfxrtr->router->rtaddr, 0, pfxrtr->router->ifp);
 1331                 IF_AFDATA_RUNLOCK(pfxrtr->router->ifp);
 1332                 if (ln == NULL)
 1333                         continue;
 1334                 canreach = ND6_IS_LLINFO_PROBREACH(ln);
 1335                 LLE_RUNLOCK(ln);
 1336                 if (canreach)
 1337                         break;
 1338         }
 1339         return (pfxrtr);
 1340 }
 1341 
 1342 /*
 1343  * Check if each prefix in the prefix list has at least one available router
 1344  * that advertised the prefix (a router is "available" if its neighbor cache
 1345  * entry is reachable or probably reachable).
 1346  * If the check fails, the prefix may be off-link, because, for example,
 1347  * we have moved from the network but the lifetime of the prefix has not
 1348  * expired yet.  So we should not use the prefix if there is another prefix
 1349  * that has an available router.
 1350  * But, if there is no prefix that has an available router, we still regards
 1351  * all the prefixes as on-link.  This is because we can't tell if all the
 1352  * routers are simply dead or if we really moved from the network and there
 1353  * is no router around us.
 1354  */
 1355 void
 1356 pfxlist_onlink_check()
 1357 {
 1358         struct nd_prefix *pr;
 1359         struct in6_ifaddr *ifa;
 1360         struct nd_defrouter *dr;
 1361         struct nd_pfxrouter *pfxrtr = NULL;
 1362 
 1363         /*
 1364          * Check if there is a prefix that has a reachable advertising
 1365          * router.
 1366          */
 1367         LIST_FOREACH(pr, &V_nd_prefix, ndpr_entry) {
 1368                 if (pr->ndpr_raf_onlink && find_pfxlist_reachable_router(pr))
 1369                         break;
 1370         }
 1371 
 1372         /*
 1373          * If we have no such prefix, check whether we still have a router
 1374          * that does not advertise any prefixes.
 1375          */
 1376         if (pr == NULL) {
 1377                 TAILQ_FOREACH(dr, &V_nd_defrouter, dr_entry) {
 1378                         struct nd_prefix *pr0;
 1379 
 1380                         LIST_FOREACH(pr0, &V_nd_prefix, ndpr_entry) {
 1381                                 if ((pfxrtr = pfxrtr_lookup(pr0, dr)) != NULL)
 1382                                         break;
 1383                         }
 1384                         if (pfxrtr != NULL)
 1385                                 break;
 1386                 }
 1387         }
 1388         if (pr != NULL || (!TAILQ_EMPTY(&V_nd_defrouter) && pfxrtr == NULL)) {
 1389                 /*
 1390                  * There is at least one prefix that has a reachable router,
 1391                  * or at least a router which probably does not advertise
 1392                  * any prefixes.  The latter would be the case when we move
 1393                  * to a new link where we have a router that does not provide
 1394                  * prefixes and we configure an address by hand.
 1395                  * Detach prefixes which have no reachable advertising
 1396                  * router, and attach other prefixes.
 1397                  */
 1398                 LIST_FOREACH(pr, &V_nd_prefix, ndpr_entry) {
 1399                         /* XXX: a link-local prefix should never be detached */
 1400                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1401                                 continue;
 1402 
 1403                         /*
 1404                          * we aren't interested in prefixes without the L bit
 1405                          * set.
 1406                          */
 1407                         if (pr->ndpr_raf_onlink == 0)
 1408                                 continue;
 1409 
 1410                         if (pr->ndpr_raf_auto == 0)
 1411                                 continue;
 1412 
 1413                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1414                             find_pfxlist_reachable_router(pr) == NULL)
 1415                                 pr->ndpr_stateflags |= NDPRF_DETACHED;
 1416                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1417                             find_pfxlist_reachable_router(pr) != 0)
 1418                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1419                 }
 1420         } else {
 1421                 /* there is no prefix that has a reachable router */
 1422                 LIST_FOREACH(pr, &V_nd_prefix, ndpr_entry) {
 1423                         if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1424                                 continue;
 1425 
 1426                         if (pr->ndpr_raf_onlink == 0)
 1427                                 continue;
 1428 
 1429                         if (pr->ndpr_raf_auto == 0)
 1430                                 continue;
 1431 
 1432                         if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1433                                 pr->ndpr_stateflags &= ~NDPRF_DETACHED;
 1434                 }
 1435         }
 1436 
 1437         /*
 1438          * Remove each interface route associated with a (just) detached
 1439          * prefix, and reinstall the interface route for a (just) attached
 1440          * prefix.  Note that all attempt of reinstallation does not
 1441          * necessarily success, when a same prefix is shared among multiple
 1442          * interfaces.  Such cases will be handled in nd6_prefix_onlink,
 1443          * so we don't have to care about them.
 1444          */
 1445         LIST_FOREACH(pr, &V_nd_prefix, ndpr_entry) {
 1446                 int e;
 1447                 char ip6buf[INET6_ADDRSTRLEN];
 1448 
 1449                 if (IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr))
 1450                         continue;
 1451 
 1452                 if (pr->ndpr_raf_onlink == 0)
 1453                         continue;
 1454 
 1455                 if (pr->ndpr_raf_auto == 0)
 1456                         continue;
 1457 
 1458                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) != 0 &&
 1459                     (pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1460                         if ((e = nd6_prefix_offlink(pr)) != 0) {
 1461                                 nd6log((LOG_ERR,
 1462                                     "pfxlist_onlink_check: failed to "
 1463                                     "make %s/%d offlink, errno=%d\n",
 1464                                     ip6_sprintf(ip6buf,
 1465                                             &pr->ndpr_prefix.sin6_addr),
 1466                                             pr->ndpr_plen, e));
 1467                         }
 1468                 }
 1469                 if ((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
 1470                     (pr->ndpr_stateflags & NDPRF_ONLINK) == 0 &&
 1471                     pr->ndpr_raf_onlink) {
 1472                         if ((e = nd6_prefix_onlink(pr)) != 0) {
 1473                                 nd6log((LOG_ERR,
 1474                                     "pfxlist_onlink_check: failed to "
 1475                                     "make %s/%d onlink, errno=%d\n",
 1476                                     ip6_sprintf(ip6buf,
 1477                                             &pr->ndpr_prefix.sin6_addr),
 1478                                             pr->ndpr_plen, e));
 1479                         }
 1480                 }
 1481         }
 1482 
 1483         /*
 1484          * Changes on the prefix status might affect address status as well.
 1485          * Make sure that all addresses derived from an attached prefix are
 1486          * attached, and that all addresses derived from a detached prefix are
 1487          * detached.  Note, however, that a manually configured address should
 1488          * always be attached.
 1489          * The precise detection logic is same as the one for prefixes.
 1490          *
 1491          * XXXRW: in6_ifaddrhead locking.
 1492          */
 1493         TAILQ_FOREACH(ifa, &V_in6_ifaddrhead, ia_link) {
 1494                 if (!(ifa->ia6_flags & IN6_IFF_AUTOCONF))
 1495                         continue;
 1496 
 1497                 if (ifa->ia6_ndpr == NULL) {
 1498                         /*
 1499                          * This can happen when we first configure the address
 1500                          * (i.e. the address exists, but the prefix does not).
 1501                          * XXX: complicated relationships...
 1502                          */
 1503                         continue;
 1504                 }
 1505 
 1506                 if (find_pfxlist_reachable_router(ifa->ia6_ndpr))
 1507                         break;
 1508         }
 1509         if (ifa) {
 1510                 TAILQ_FOREACH(ifa, &V_in6_ifaddrhead, ia_link) {
 1511                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1512                                 continue;
 1513 
 1514                         if (ifa->ia6_ndpr == NULL) /* XXX: see above. */
 1515                                 continue;
 1516 
 1517                         if (find_pfxlist_reachable_router(ifa->ia6_ndpr)) {
 1518                                 if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1519                                         ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1520                                         ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1521                                         nd6_dad_start((struct ifaddr *)ifa, 0);
 1522                                 }
 1523                         } else {
 1524                                 ifa->ia6_flags |= IN6_IFF_DETACHED;
 1525                         }
 1526                 }
 1527         }
 1528         else {
 1529                 TAILQ_FOREACH(ifa, &V_in6_ifaddrhead, ia_link) {
 1530                         if ((ifa->ia6_flags & IN6_IFF_AUTOCONF) == 0)
 1531                                 continue;
 1532 
 1533                         if (ifa->ia6_flags & IN6_IFF_DETACHED) {
 1534                                 ifa->ia6_flags &= ~IN6_IFF_DETACHED;
 1535                                 ifa->ia6_flags |= IN6_IFF_TENTATIVE;
 1536                                 /* Do we need a delay in this case? */
 1537                                 nd6_dad_start((struct ifaddr *)ifa, 0);
 1538                         }
 1539                 }
 1540         }
 1541 }
 1542 
 1543 static int
 1544 nd6_prefix_onlink_rtrequest(struct nd_prefix *pr, struct ifaddr *ifa)
 1545 {
 1546         static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
 1547         struct radix_node_head *rnh;
 1548         struct rtentry *rt;
 1549         struct sockaddr_in6 mask6;
 1550         u_long rtflags;
 1551         int error, a_failure, fibnum;
 1552 
 1553         /*
 1554          * in6_ifinit() sets nd6_rtrequest to ifa_rtrequest for all ifaddrs.
 1555          * ifa->ifa_rtrequest = nd6_rtrequest;
 1556          */
 1557         bzero(&mask6, sizeof(mask6));
 1558         mask6.sin6_len = sizeof(mask6);
 1559         mask6.sin6_addr = pr->ndpr_mask;
 1560         rtflags = (ifa->ifa_flags & ~IFA_RTSELF) | RTF_UP;
 1561 
 1562         a_failure = 0;
 1563         for (fibnum = 0; fibnum < rt_numfibs; fibnum++) {
 1564 
 1565                 rt = NULL;
 1566                 error = in6_rtrequest(RTM_ADD,
 1567                     (struct sockaddr *)&pr->ndpr_prefix, ifa->ifa_addr,
 1568                     (struct sockaddr *)&mask6, rtflags, &rt, fibnum);
 1569                 if (error == 0) {
 1570                         KASSERT(rt != NULL, ("%s: in6_rtrequest return no "
 1571                             "error(%d) but rt is NULL, pr=%p, ifa=%p", __func__,
 1572                             error, pr, ifa));
 1573 
 1574                         rnh = rt_tables_get_rnh(rt->rt_fibnum, AF_INET6);
 1575                         /* XXX what if rhn == NULL? */
 1576                         RADIX_NODE_HEAD_LOCK(rnh);
 1577                         RT_LOCK(rt);
 1578                         if (rt_setgate(rt, rt_key(rt),
 1579                             (struct sockaddr *)&null_sdl) == 0) {
 1580                                 struct sockaddr_dl *dl;
 1581 
 1582                                 dl = (struct sockaddr_dl *)rt->rt_gateway;
 1583                                 dl->sdl_type = rt->rt_ifp->if_type;
 1584                                 dl->sdl_index = rt->rt_ifp->if_index;
 1585                         }
 1586                         RADIX_NODE_HEAD_UNLOCK(rnh);
 1587                         nd6_rtmsg(RTM_ADD, rt);
 1588                         RT_UNLOCK(rt);
 1589                         pr->ndpr_stateflags |= NDPRF_ONLINK;
 1590                 } else {
 1591                         char ip6buf[INET6_ADDRSTRLEN];
 1592                         char ip6bufg[INET6_ADDRSTRLEN];
 1593                         char ip6bufm[INET6_ADDRSTRLEN];
 1594                         struct sockaddr_in6 *sin6;
 1595 
 1596                         sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
 1597                         nd6log((LOG_ERR, "nd6_prefix_onlink: failed to add "
 1598                             "route for a prefix (%s/%d) on %s, gw=%s, mask=%s, "
 1599                             "flags=%lx errno = %d\n",
 1600                             ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1601                             pr->ndpr_plen, if_name(pr->ndpr_ifp),
 1602                             ip6_sprintf(ip6bufg, &sin6->sin6_addr),
 1603                             ip6_sprintf(ip6bufm, &mask6.sin6_addr),
 1604                             rtflags, error));
 1605 
 1606                         /* Save last error to return, see rtinit(). */
 1607                         a_failure = error;
 1608                 }
 1609 
 1610                 if (rt != NULL) {
 1611                         RT_LOCK(rt);
 1612                         RT_REMREF(rt);
 1613                         RT_UNLOCK(rt);
 1614                 }
 1615         }
 1616 
 1617         /* Return the last error we got. */
 1618         return (a_failure);
 1619 }
 1620 
 1621 static int
 1622 nd6_prefix_onlink(struct nd_prefix *pr)
 1623 {
 1624         struct ifaddr *ifa;
 1625         struct ifnet *ifp = pr->ndpr_ifp;
 1626         struct nd_prefix *opr;
 1627         int error = 0;
 1628         char ip6buf[INET6_ADDRSTRLEN];
 1629 
 1630         /* sanity check */
 1631         if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0) {
 1632                 nd6log((LOG_ERR,
 1633                     "nd6_prefix_onlink: %s/%d is already on-link\n",
 1634                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1635                     pr->ndpr_plen));
 1636                 return (EEXIST);
 1637         }
 1638 
 1639         /*
 1640          * Add the interface route associated with the prefix.  Before
 1641          * installing the route, check if there's the same prefix on another
 1642          * interface, and the prefix has already installed the interface route.
 1643          * Although such a configuration is expected to be rare, we explicitly
 1644          * allow it.
 1645          */
 1646         LIST_FOREACH(opr, &V_nd_prefix, ndpr_entry) {
 1647                 if (opr == pr)
 1648                         continue;
 1649 
 1650                 if ((opr->ndpr_stateflags & NDPRF_ONLINK) == 0)
 1651                         continue;
 1652 
 1653                 if (opr->ndpr_plen == pr->ndpr_plen &&
 1654                     in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1655                     &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen))
 1656                         return (0);
 1657         }
 1658 
 1659         /*
 1660          * We prefer link-local addresses as the associated interface address.
 1661          */
 1662         /* search for a link-local addr */
 1663         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
 1664             IN6_IFF_NOTREADY | IN6_IFF_ANYCAST);
 1665         if (ifa == NULL) {
 1666                 /* XXX: freebsd does not have ifa_ifwithaf */
 1667                 IF_ADDR_RLOCK(ifp);
 1668                 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 1669                         if (ifa->ifa_addr->sa_family == AF_INET6)
 1670                                 break;
 1671                 }
 1672                 if (ifa != NULL)
 1673                         ifa_ref(ifa);
 1674                 IF_ADDR_RUNLOCK(ifp);
 1675                 /* should we care about ia6_flags? */
 1676         }
 1677         if (ifa == NULL) {
 1678                 /*
 1679                  * This can still happen, when, for example, we receive an RA
 1680                  * containing a prefix with the L bit set and the A bit clear,
 1681                  * after removing all IPv6 addresses on the receiving
 1682                  * interface.  This should, of course, be rare though.
 1683                  */
 1684                 nd6log((LOG_NOTICE,
 1685                     "nd6_prefix_onlink: failed to find any ifaddr"
 1686                     " to add route for a prefix(%s/%d) on %s\n",
 1687                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1688                     pr->ndpr_plen, if_name(ifp)));
 1689                 return (0);
 1690         }
 1691 
 1692         error = nd6_prefix_onlink_rtrequest(pr, ifa);
 1693 
 1694         if (ifa != NULL)
 1695                 ifa_free(ifa);
 1696 
 1697         return (error);
 1698 }
 1699 
 1700 static int
 1701 nd6_prefix_offlink(struct nd_prefix *pr)
 1702 {
 1703         int error = 0;
 1704         struct ifnet *ifp = pr->ndpr_ifp;
 1705         struct nd_prefix *opr;
 1706         struct sockaddr_in6 sa6, mask6;
 1707         struct rtentry *rt;
 1708         char ip6buf[INET6_ADDRSTRLEN];
 1709         int fibnum, a_failure;
 1710 
 1711         /* sanity check */
 1712         if ((pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
 1713                 nd6log((LOG_ERR,
 1714                     "nd6_prefix_offlink: %s/%d is already off-link\n",
 1715                     ip6_sprintf(ip6buf, &pr->ndpr_prefix.sin6_addr),
 1716                     pr->ndpr_plen));
 1717                 return (EEXIST);
 1718         }
 1719 
 1720         bzero(&sa6, sizeof(sa6));
 1721         sa6.sin6_family = AF_INET6;
 1722         sa6.sin6_len = sizeof(sa6);
 1723         bcopy(&pr->ndpr_prefix.sin6_addr, &sa6.sin6_addr,
 1724             sizeof(struct in6_addr));
 1725         bzero(&mask6, sizeof(mask6));
 1726         mask6.sin6_family = AF_INET6;
 1727         mask6.sin6_len = sizeof(sa6);
 1728         bcopy(&pr->ndpr_mask, &mask6.sin6_addr, sizeof(struct in6_addr));
 1729 
 1730         a_failure = 0;
 1731         for (fibnum = 0; fibnum < rt_numfibs; fibnum++) {
 1732                 rt = NULL;
 1733                 error = in6_rtrequest(RTM_DELETE, (struct sockaddr *)&sa6, NULL,
 1734                     (struct sockaddr *)&mask6, 0, &rt, fibnum);
 1735                 if (error == 0) {
 1736                         /* report the route deletion to the routing socket. */
 1737                         if (rt != NULL)
 1738                                 nd6_rtmsg(RTM_DELETE, rt);
 1739                 } else {
 1740                         /* Save last error to return, see rtinit(). */
 1741                         a_failure = error;
 1742                 }
 1743                 if (rt != NULL) {
 1744                         RTFREE(rt);
 1745                 }
 1746         }
 1747         error = a_failure;
 1748         if (error == 0) {
 1749                 pr->ndpr_stateflags &= ~NDPRF_ONLINK;
 1750 
 1751                 /*
 1752                  * There might be the same prefix on another interface,
 1753                  * the prefix which could not be on-link just because we have
 1754                  * the interface route (see comments in nd6_prefix_onlink).
 1755                  * If there's one, try to make the prefix on-link on the
 1756                  * interface.
 1757                  */
 1758                 LIST_FOREACH(opr, &V_nd_prefix, ndpr_entry) {
 1759                         if (opr == pr)
 1760                                 continue;
 1761 
 1762                         if ((opr->ndpr_stateflags & NDPRF_ONLINK) != 0)
 1763                                 continue;
 1764 
 1765                         /*
 1766                          * KAME specific: detached prefixes should not be
 1767                          * on-link.
 1768                          */
 1769                         if ((opr->ndpr_stateflags & NDPRF_DETACHED) != 0)
 1770                                 continue;
 1771 
 1772                         if (opr->ndpr_plen == pr->ndpr_plen &&
 1773                             in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
 1774                             &opr->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
 1775                                 int e;
 1776 
 1777                                 if ((e = nd6_prefix_onlink(opr)) != 0) {
 1778                                         nd6log((LOG_ERR,
 1779                                             "nd6_prefix_offlink: failed to "
 1780                                             "recover a prefix %s/%d from %s "
 1781                                             "to %s (errno = %d)\n",
 1782                                             ip6_sprintf(ip6buf,
 1783                                                 &opr->ndpr_prefix.sin6_addr),
 1784                                             opr->ndpr_plen, if_name(ifp),
 1785                                             if_name(opr->ndpr_ifp), e));
 1786                                 }
 1787                         }
 1788                 }
 1789         } else {
 1790                 /* XXX: can we still set the NDPRF_ONLINK flag? */
 1791                 nd6log((LOG_ERR,
 1792                     "nd6_prefix_offlink: failed to delete route: "
 1793                     "%s/%d on %s (errno = %d)\n",
 1794                     ip6_sprintf(ip6buf, &sa6.sin6_addr), pr->ndpr_plen,
 1795                     if_name(ifp), error));
 1796         }
 1797 
 1798         return (error);
 1799 }
 1800 
 1801 static struct in6_ifaddr *
 1802 in6_ifadd(struct nd_prefixctl *pr, int mcast)
 1803 {
 1804         struct ifnet *ifp = pr->ndpr_ifp;
 1805         struct ifaddr *ifa;
 1806         struct in6_aliasreq ifra;
 1807         struct in6_ifaddr *ia, *ib;
 1808         int error, plen0;
 1809         struct in6_addr mask;
 1810         int prefixlen = pr->ndpr_plen;
 1811         int updateflags;
 1812         char ip6buf[INET6_ADDRSTRLEN];
 1813 
 1814         in6_prefixlen2mask(&mask, prefixlen);
 1815 
 1816         /*
 1817          * find a link-local address (will be interface ID).
 1818          * Is it really mandatory? Theoretically, a global or a site-local
 1819          * address can be configured without a link-local address, if we
 1820          * have a unique interface identifier...
 1821          *
 1822          * it is not mandatory to have a link-local address, we can generate
 1823          * interface identifier on the fly.  we do this because:
 1824          * (1) it should be the easiest way to find interface identifier.
 1825          * (2) RFC2462 5.4 suggesting the use of the same interface identifier
 1826          * for multiple addresses on a single interface, and possible shortcut
 1827          * of DAD.  we omitted DAD for this reason in the past.
 1828          * (3) a user can prevent autoconfiguration of global address
 1829          * by removing link-local address by hand (this is partly because we
 1830          * don't have other way to control the use of IPv6 on an interface.
 1831          * this has been our design choice - cf. NRL's "ifconfig auto").
 1832          * (4) it is easier to manage when an interface has addresses
 1833          * with the same interface identifier, than to have multiple addresses
 1834          * with different interface identifiers.
 1835          */
 1836         ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp, 0); /* 0 is OK? */
 1837         if (ifa)
 1838                 ib = (struct in6_ifaddr *)ifa;
 1839         else
 1840                 return NULL;
 1841 
 1842         /* prefixlen + ifidlen must be equal to 128 */
 1843         plen0 = in6_mask2len(&ib->ia_prefixmask.sin6_addr, NULL);
 1844         if (prefixlen != plen0) {
 1845                 ifa_free(ifa);
 1846                 nd6log((LOG_INFO, "in6_ifadd: wrong prefixlen for %s "
 1847                     "(prefix=%d ifid=%d)\n",
 1848                     if_name(ifp), prefixlen, 128 - plen0));
 1849                 return NULL;
 1850         }
 1851 
 1852         /* make ifaddr */
 1853 
 1854         bzero(&ifra, sizeof(ifra));
 1855         /*
 1856          * in6_update_ifa() does not use ifra_name, but we accurately set it
 1857          * for safety.
 1858          */
 1859         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1860         ifra.ifra_addr.sin6_family = AF_INET6;
 1861         ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
 1862         /* prefix */
 1863         ifra.ifra_addr.sin6_addr = pr->ndpr_prefix.sin6_addr;
 1864         ifra.ifra_addr.sin6_addr.s6_addr32[0] &= mask.s6_addr32[0];
 1865         ifra.ifra_addr.sin6_addr.s6_addr32[1] &= mask.s6_addr32[1];
 1866         ifra.ifra_addr.sin6_addr.s6_addr32[2] &= mask.s6_addr32[2];
 1867         ifra.ifra_addr.sin6_addr.s6_addr32[3] &= mask.s6_addr32[3];
 1868 
 1869         /* interface ID */
 1870         ifra.ifra_addr.sin6_addr.s6_addr32[0] |=
 1871             (ib->ia_addr.sin6_addr.s6_addr32[0] & ~mask.s6_addr32[0]);
 1872         ifra.ifra_addr.sin6_addr.s6_addr32[1] |=
 1873             (ib->ia_addr.sin6_addr.s6_addr32[1] & ~mask.s6_addr32[1]);
 1874         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1875             (ib->ia_addr.sin6_addr.s6_addr32[2] & ~mask.s6_addr32[2]);
 1876         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1877             (ib->ia_addr.sin6_addr.s6_addr32[3] & ~mask.s6_addr32[3]);
 1878         ifa_free(ifa);
 1879 
 1880         /* new prefix mask. */
 1881         ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
 1882         ifra.ifra_prefixmask.sin6_family = AF_INET6;
 1883         bcopy(&mask, &ifra.ifra_prefixmask.sin6_addr,
 1884             sizeof(ifra.ifra_prefixmask.sin6_addr));
 1885 
 1886         /* lifetimes. */
 1887         ifra.ifra_lifetime.ia6t_vltime = pr->ndpr_vltime;
 1888         ifra.ifra_lifetime.ia6t_pltime = pr->ndpr_pltime;
 1889 
 1890         /* XXX: scope zone ID? */
 1891 
 1892         ifra.ifra_flags |= IN6_IFF_AUTOCONF; /* obey autoconf */
 1893 
 1894         /*
 1895          * Make sure that we do not have this address already.  This should
 1896          * usually not happen, but we can still see this case, e.g., if we
 1897          * have manually configured the exact address to be configured.
 1898          */
 1899         ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp,
 1900             &ifra.ifra_addr.sin6_addr);
 1901         if (ifa != NULL) {
 1902                 ifa_free(ifa);
 1903                 /* this should be rare enough to make an explicit log */
 1904                 log(LOG_INFO, "in6_ifadd: %s is already configured\n",
 1905                     ip6_sprintf(ip6buf, &ifra.ifra_addr.sin6_addr));
 1906                 return (NULL);
 1907         }
 1908 
 1909         /*
 1910          * Allocate ifaddr structure, link into chain, etc.
 1911          * If we are going to create a new address upon receiving a multicasted
 1912          * RA, we need to impose a random delay before starting DAD.
 1913          * [draft-ietf-ipv6-rfc2462bis-02.txt, Section 5.4.2]
 1914          */
 1915         updateflags = 0;
 1916         if (mcast)
 1917                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 1918         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0) {
 1919                 nd6log((LOG_ERR,
 1920                     "in6_ifadd: failed to make ifaddr %s on %s (errno=%d)\n",
 1921                     ip6_sprintf(ip6buf, &ifra.ifra_addr.sin6_addr),
 1922                     if_name(ifp), error));
 1923                 return (NULL);  /* ifaddr must not have been allocated. */
 1924         }
 1925 
 1926         ia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 1927         /*
 1928          * XXXRW: Assumption of non-NULLness here might not be true with
 1929          * fine-grained locking -- should we validate it?  Or just return
 1930          * earlier ifa rather than looking it up again?
 1931          */
 1932         return (ia);            /* this is always non-NULL  and referenced. */
 1933 }
 1934 
 1935 /*
 1936  * ia0 - corresponding public address
 1937  */
 1938 int
 1939 in6_tmpifadd(const struct in6_ifaddr *ia0, int forcegen, int delay)
 1940 {
 1941         struct ifnet *ifp = ia0->ia_ifa.ifa_ifp;
 1942         struct in6_ifaddr *newia, *ia;
 1943         struct in6_aliasreq ifra;
 1944         int i, error;
 1945         int trylimit = 3;       /* XXX: adhoc value */
 1946         int updateflags;
 1947         u_int32_t randid[2];
 1948         time_t vltime0, pltime0;
 1949 
 1950         bzero(&ifra, sizeof(ifra));
 1951         strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
 1952         ifra.ifra_addr = ia0->ia_addr;
 1953         /* copy prefix mask */
 1954         ifra.ifra_prefixmask = ia0->ia_prefixmask;
 1955         /* clear the old IFID */
 1956         for (i = 0; i < 4; i++) {
 1957                 ifra.ifra_addr.sin6_addr.s6_addr32[i] &=
 1958                     ifra.ifra_prefixmask.sin6_addr.s6_addr32[i];
 1959         }
 1960 
 1961   again:
 1962         if (in6_get_tmpifid(ifp, (u_int8_t *)randid,
 1963             (const u_int8_t *)&ia0->ia_addr.sin6_addr.s6_addr[8], forcegen)) {
 1964                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to find a good "
 1965                     "random IFID\n"));
 1966                 return (EINVAL);
 1967         }
 1968         ifra.ifra_addr.sin6_addr.s6_addr32[2] |=
 1969             (randid[0] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[2]));
 1970         ifra.ifra_addr.sin6_addr.s6_addr32[3] |=
 1971             (randid[1] & ~(ifra.ifra_prefixmask.sin6_addr.s6_addr32[3]));
 1972 
 1973         /*
 1974          * in6_get_tmpifid() quite likely provided a unique interface ID.
 1975          * However, we may still have a chance to see collision, because
 1976          * there may be a time lag between generation of the ID and generation
 1977          * of the address.  So, we'll do one more sanity check.
 1978          */
 1979         IN6_IFADDR_RLOCK();
 1980         TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) {
 1981                 if (IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
 1982                     &ifra.ifra_addr.sin6_addr)) {
 1983                         if (trylimit-- == 0) {
 1984                                 IN6_IFADDR_RUNLOCK();
 1985                                 /*
 1986                                  * Give up.  Something strange should have
 1987                                  * happened.
 1988                                  */
 1989                                 nd6log((LOG_NOTICE, "in6_tmpifadd: failed to "
 1990                                     "find a unique random IFID\n"));
 1991                                 return (EEXIST);
 1992                         }
 1993                         IN6_IFADDR_RUNLOCK();
 1994                         forcegen = 1;
 1995                         goto again;
 1996                 }
 1997         }
 1998         IN6_IFADDR_RUNLOCK();
 1999 
 2000         /*
 2001          * The Valid Lifetime is the lower of the Valid Lifetime of the
 2002          * public address or TEMP_VALID_LIFETIME.
 2003          * The Preferred Lifetime is the lower of the Preferred Lifetime
 2004          * of the public address or TEMP_PREFERRED_LIFETIME -
 2005          * DESYNC_FACTOR.
 2006          */
 2007         if (ia0->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
 2008                 vltime0 = IFA6_IS_INVALID(ia0) ? 0 :
 2009                     (ia0->ia6_lifetime.ia6t_vltime -
 2010                     (time_second - ia0->ia6_updatetime));
 2011                 if (vltime0 > V_ip6_temp_valid_lifetime)
 2012                         vltime0 = V_ip6_temp_valid_lifetime;
 2013         } else
 2014                 vltime0 = V_ip6_temp_valid_lifetime;
 2015         if (ia0->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
 2016                 pltime0 = IFA6_IS_DEPRECATED(ia0) ? 0 :
 2017                     (ia0->ia6_lifetime.ia6t_pltime -
 2018                     (time_second - ia0->ia6_updatetime));
 2019                 if (pltime0 > V_ip6_temp_preferred_lifetime - V_ip6_desync_factor){
 2020                         pltime0 = V_ip6_temp_preferred_lifetime -
 2021                             V_ip6_desync_factor;
 2022                 }
 2023         } else
 2024                 pltime0 = V_ip6_temp_preferred_lifetime - V_ip6_desync_factor;
 2025         ifra.ifra_lifetime.ia6t_vltime = vltime0;
 2026         ifra.ifra_lifetime.ia6t_pltime = pltime0;
 2027 
 2028         /*
 2029          * A temporary address is created only if this calculated Preferred
 2030          * Lifetime is greater than REGEN_ADVANCE time units.
 2031          */
 2032         if (ifra.ifra_lifetime.ia6t_pltime <= V_ip6_temp_regen_advance)
 2033                 return (0);
 2034 
 2035         /* XXX: scope zone ID? */
 2036 
 2037         ifra.ifra_flags |= (IN6_IFF_AUTOCONF|IN6_IFF_TEMPORARY);
 2038 
 2039         /* allocate ifaddr structure, link into chain, etc. */
 2040         updateflags = 0;
 2041         if (delay)
 2042                 updateflags |= IN6_IFAUPDATE_DADDELAY;
 2043         if ((error = in6_update_ifa(ifp, &ifra, NULL, updateflags)) != 0)
 2044                 return (error);
 2045 
 2046         newia = in6ifa_ifpwithaddr(ifp, &ifra.ifra_addr.sin6_addr);
 2047         if (newia == NULL) {    /* XXX: can it happen? */
 2048                 nd6log((LOG_ERR,
 2049                     "in6_tmpifadd: ifa update succeeded, but we got "
 2050                     "no ifaddr\n"));
 2051                 return (EINVAL); /* XXX */
 2052         }
 2053         newia->ia6_ndpr = ia0->ia6_ndpr;
 2054         newia->ia6_ndpr->ndpr_refcnt++;
 2055         ifa_free(&newia->ia_ifa);
 2056 
 2057         /*
 2058          * A newly added address might affect the status of other addresses.
 2059          * XXX: when the temporary address is generated with a new public
 2060          * address, the onlink check is redundant.  However, it would be safe
 2061          * to do the check explicitly everywhere a new address is generated,
 2062          * and, in fact, we surely need the check when we create a new
 2063          * temporary address due to deprecation of an old temporary address.
 2064          */
 2065         pfxlist_onlink_check();
 2066 
 2067         return (0);
 2068 }
 2069 
 2070 static int
 2071 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
 2072 {
 2073         if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
 2074                 ndpr->ndpr_preferred = 0;
 2075         else
 2076                 ndpr->ndpr_preferred = time_second + ndpr->ndpr_pltime;
 2077         if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
 2078                 ndpr->ndpr_expire = 0;
 2079         else
 2080                 ndpr->ndpr_expire = time_second + ndpr->ndpr_vltime;
 2081 
 2082         return 0;
 2083 }
 2084 
 2085 static void
 2086 in6_init_address_ltimes(struct nd_prefix *new, struct in6_addrlifetime *lt6)
 2087 {
 2088         /* init ia6t_expire */
 2089         if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
 2090                 lt6->ia6t_expire = 0;
 2091         else {
 2092                 lt6->ia6t_expire = time_second;
 2093                 lt6->ia6t_expire += lt6->ia6t_vltime;
 2094         }
 2095 
 2096         /* init ia6t_preferred */
 2097         if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
 2098                 lt6->ia6t_preferred = 0;
 2099         else {
 2100                 lt6->ia6t_preferred = time_second;
 2101                 lt6->ia6t_preferred += lt6->ia6t_pltime;
 2102         }
 2103 }
 2104 
 2105 /*
 2106  * Delete all the routing table entries that use the specified gateway.
 2107  * XXX: this function causes search through all entries of routing table, so
 2108  * it shouldn't be called when acting as a router.
 2109  */
 2110 void
 2111 rt6_flush(struct in6_addr *gateway, struct ifnet *ifp)
 2112 {
 2113         struct radix_node_head *rnh;
 2114         u_int fibnum;
 2115         int s = splnet();
 2116 
 2117         /* We'll care only link-local addresses */
 2118         if (!IN6_IS_ADDR_LINKLOCAL(gateway)) {
 2119                 splx(s);
 2120                 return;
 2121         }
 2122 
 2123         /* XXX Do we really need to walk any but the default FIB? */
 2124         for (fibnum = 0; fibnum < rt_numfibs; fibnum++) {
 2125                 rnh = rt_tables_get_rnh(fibnum, AF_INET6);
 2126                 if (rnh == NULL)
 2127                         continue;
 2128 
 2129                 RADIX_NODE_HEAD_LOCK(rnh);
 2130                 rnh->rnh_walktree(rnh, rt6_deleteroute, (void *)gateway);
 2131                 RADIX_NODE_HEAD_UNLOCK(rnh);
 2132         }
 2133         splx(s);
 2134 }
 2135 
 2136 static int
 2137 rt6_deleteroute(struct radix_node *rn, void *arg)
 2138 {
 2139 #define SIN6(s) ((struct sockaddr_in6 *)s)
 2140         struct rtentry *rt = (struct rtentry *)rn;
 2141         struct in6_addr *gate = (struct in6_addr *)arg;
 2142 
 2143         if (rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_INET6)
 2144                 return (0);
 2145 
 2146         if (!IN6_ARE_ADDR_EQUAL(gate, &SIN6(rt->rt_gateway)->sin6_addr)) {
 2147                 return (0);
 2148         }
 2149 
 2150         /*
 2151          * Do not delete a static route.
 2152          * XXX: this seems to be a bit ad-hoc. Should we consider the
 2153          * 'cloned' bit instead?
 2154          */
 2155         if ((rt->rt_flags & RTF_STATIC) != 0)
 2156                 return (0);
 2157 
 2158         /*
 2159          * We delete only host route. This means, in particular, we don't
 2160          * delete default route.
 2161          */
 2162         if ((rt->rt_flags & RTF_HOST) == 0)
 2163                 return (0);
 2164 
 2165         return (in6_rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
 2166             rt_mask(rt), rt->rt_flags, NULL, rt->rt_fibnum));
 2167 #undef SIN6
 2168 }
 2169 
 2170 int
 2171 nd6_setdefaultiface(int ifindex)
 2172 {
 2173         int error = 0;
 2174 
 2175         if (ifindex < 0 || V_if_index < ifindex)
 2176                 return (EINVAL);
 2177         if (ifindex != 0 && !ifnet_byindex(ifindex))
 2178                 return (EINVAL);
 2179 
 2180         if (V_nd6_defifindex != ifindex) {
 2181                 V_nd6_defifindex = ifindex;
 2182                 if (V_nd6_defifindex > 0)
 2183                         V_nd6_defifp = ifnet_byindex(V_nd6_defifindex);
 2184                 else
 2185                         V_nd6_defifp = NULL;
 2186 
 2187                 /*
 2188                  * Our current implementation assumes one-to-one maping between
 2189                  * interfaces and links, so it would be natural to use the
 2190                  * default interface as the default link.
 2191                  */
 2192                 scope6_setdefault(V_nd6_defifp);
 2193         }
 2194 
 2195         return (error);
 2196 }

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