The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netinet6/in6_src.c

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    1 /*      $FreeBSD: releng/5.2/sys/netinet6/in6_src.c 122922 2003-11-20 20:07:39Z andre $ */
    2 /*      $KAME: in6_src.c,v 1.132 2003/08/26 04:42:27 keiichi Exp $      */
    3 
    4 /*
    5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. Neither the name of the project nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  */
   32 
   33 /*
   34  * Copyright (c) 1982, 1986, 1991, 1993
   35  *      The Regents of the University of California.  All rights reserved.
   36  *
   37  * Redistribution and use in source and binary forms, with or without
   38  * modification, are permitted provided that the following conditions
   39  * are met:
   40  * 1. Redistributions of source code must retain the above copyright
   41  *    notice, this list of conditions and the following disclaimer.
   42  * 2. Redistributions in binary form must reproduce the above copyright
   43  *    notice, this list of conditions and the following disclaimer in the
   44  *    documentation and/or other materials provided with the distribution.
   45  * 3. All advertising materials mentioning features or use of this software
   46  *    must display the following acknowledgement:
   47  *      This product includes software developed by the University of
   48  *      California, Berkeley and its contributors.
   49  * 4. Neither the name of the University nor the names of its contributors
   50  *    may be used to endorse or promote products derived from this software
   51  *    without specific prior written permission.
   52  *
   53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   63  * SUCH DAMAGE.
   64  *
   65  *      @(#)in_pcb.c    8.2 (Berkeley) 1/4/94
   66  */
   67 
   68 #include "opt_inet.h"
   69 #include "opt_inet6.h"
   70 
   71 #include <sys/param.h>
   72 #include <sys/systm.h>
   73 #include <sys/malloc.h>
   74 #include <sys/mbuf.h>
   75 #include <sys/protosw.h>
   76 #include <sys/socket.h>
   77 #include <sys/socketvar.h>
   78 #include <sys/sockio.h>
   79 #include <sys/sysctl.h>
   80 #include <sys/errno.h>
   81 #include <sys/time.h>
   82 #include <sys/kernel.h>
   83 
   84 #include <net/if.h>
   85 #include <net/route.h>
   86 
   87 #include <netinet/in.h>
   88 #include <netinet/in_var.h>
   89 #include <netinet/in_systm.h>
   90 #include <netinet/ip.h>
   91 #include <netinet/in_pcb.h>
   92 #include <netinet6/in6_var.h>
   93 #include <netinet/ip6.h>
   94 #include <netinet6/in6_pcb.h>
   95 #include <netinet6/ip6_var.h>
   96 #include <netinet6/nd6.h>
   97 #ifdef ENABLE_DEFAULT_SCOPE
   98 #include <netinet6/scope6_var.h>
   99 #endif
  100 
  101 #include <net/net_osdep.h>
  102 
  103 static struct mtx addrsel_lock;
  104 #define ADDRSEL_LOCK_INIT()     mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF)
  105 #define ADDRSEL_LOCK()          mtx_lock(&addrsel_lock)
  106 #define ADDRSEL_UNLOCK()        mtx_unlock(&addrsel_lock)
  107 #define ADDRSEL_LOCK_ASSERT()   mtx_assert(&addrsel_lock, MA_OWNED)
  108 
  109 #define ADDR_LABEL_NOTAPP (-1)
  110 struct in6_addrpolicy defaultaddrpolicy;
  111 
  112 int ip6_prefer_tempaddr = 0;
  113 
  114 static int in6_selectif __P((struct sockaddr_in6 *, struct ip6_pktopts *,
  115                              struct ip6_moptions *,
  116                              struct route_in6 *ro,
  117                              struct ifnet **));
  118 
  119 static struct in6_addrpolicy *lookup_addrsel_policy __P((struct sockaddr_in6 *));
  120 
  121 static void init_policy_queue __P((void));
  122 static int add_addrsel_policyent __P((struct in6_addrpolicy *));
  123 static int delete_addrsel_policyent __P((struct in6_addrpolicy *));
  124 static int walk_addrsel_policy __P((int (*)(struct in6_addrpolicy *, void *),
  125                                     void *));
  126 static int dump_addrsel_policyent __P((struct in6_addrpolicy *, void *));
  127 static struct in6_addrpolicy *match_addrsel_policy __P((struct sockaddr_in6 *));
  128 
  129 /*
  130  * Return an IPv6 address, which is the most appropriate for a given
  131  * destination and user specified options.
  132  * If necessary, this function lookups the routing table and returns
  133  * an entry to the caller for later use.
  134  */
  135 #define REPLACE(r) do {\
  136         if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \
  137                 sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
  138                 ip6stat.ip6s_sources_rule[(r)]++; \
  139         /* printf("in6_selectsrc: replace %s with %s by %d\n", ia_best ? ip6_sprintf(&ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(&ia->ia_addr.sin6_addr), (r)); */ \
  140         goto replace; \
  141 } while(0)
  142 #define NEXT(r) do {\
  143         if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \
  144                 sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
  145                 ip6stat.ip6s_sources_rule[(r)]++; \
  146         /* printf("in6_selectsrc: keep %s against %s by %d\n", ia_best ? ip6_sprintf(&ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(&ia->ia_addr.sin6_addr), (r)); */ \
  147         goto next;              /* XXX: we can't use 'continue' here */ \
  148 } while(0)
  149 #define BREAK(r) do { \
  150         if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \
  151                 sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
  152                 ip6stat.ip6s_sources_rule[(r)]++; \
  153         goto out;               /* XXX: we can't use 'break' here */ \
  154 } while(0)
  155 
  156 struct in6_addr *
  157 in6_selectsrc(dstsock, opts, mopts, ro, laddr, errorp)
  158         struct sockaddr_in6 *dstsock;
  159         struct ip6_pktopts *opts;
  160         struct ip6_moptions *mopts;
  161         struct route_in6 *ro;
  162         struct in6_addr *laddr;
  163         int *errorp;
  164 {
  165         struct in6_addr *dst;
  166         struct ifnet *ifp = NULL;
  167         struct in6_ifaddr *ia = NULL, *ia_best = NULL;
  168         struct in6_pktinfo *pi = NULL;
  169         int dst_scope = -1, best_scope = -1, best_matchlen = -1;
  170         struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL;
  171         u_int32_t odstzone;
  172         int prefer_tempaddr;
  173         struct sockaddr_in6 dstsock0;
  174 
  175         dstsock0 = *dstsock;
  176         if (IN6_IS_SCOPE_LINKLOCAL(&dstsock0.sin6_addr) ||
  177             IN6_IS_ADDR_MC_INTFACELOCAL(&dstsock0.sin6_addr)) {
  178                 /* KAME assumption: link id == interface id */
  179                 if (opts && opts->ip6po_pktinfo &&
  180                     opts->ip6po_pktinfo->ipi6_ifindex) {
  181                         ifp = ifnet_byindex(opts->ip6po_pktinfo->ipi6_ifindex);
  182                         dstsock0.sin6_addr.s6_addr16[1] =
  183                             htons(opts->ip6po_pktinfo->ipi6_ifindex);
  184                 } else if (mopts &&
  185                     IN6_IS_ADDR_MULTICAST(&dstsock0.sin6_addr) &&
  186                     mopts->im6o_multicast_ifp) {
  187                         ifp = mopts->im6o_multicast_ifp;
  188                         dstsock0.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
  189                 } else if ((*errorp = in6_embedscope(&dstsock0.sin6_addr,
  190                     &dstsock0, NULL, NULL)) != 0)
  191                         return (NULL);
  192         }
  193         dstsock = &dstsock0;
  194 
  195         dst = &dstsock->sin6_addr;
  196         *errorp = 0;
  197 
  198         /*
  199          * If the source address is explicitly specified by the caller,
  200          * check if the requested source address is indeed a unicast address
  201          * assigned to the node, and can be used as the packet's source
  202          * address.  If everything is okay, use the address as source.
  203          */
  204         if (opts && (pi = opts->ip6po_pktinfo) &&
  205             !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
  206                 struct sockaddr_in6 srcsock;
  207                 struct in6_ifaddr *ia6;
  208 
  209                 /* get the outgoing interface */
  210                 if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp))
  211                     != 0) {
  212                         return (NULL);
  213                 }
  214                 /*
  215                  * determine the appropriate zone id of the source based on
  216                  * the zone of the destination and the outgoing interface.
  217                  */
  218                 bzero(&srcsock, sizeof(srcsock));
  219                 srcsock.sin6_family = AF_INET6;
  220                 srcsock.sin6_len = sizeof(srcsock);
  221                 srcsock.sin6_addr = pi->ipi6_addr;
  222                 if (ifp) {
  223                         if (in6_addr2zoneid(ifp, &pi->ipi6_addr,
  224                                             &srcsock.sin6_scope_id)) {
  225                                 *errorp = EINVAL; /* XXX */
  226                                 return (NULL);
  227                         }
  228                 }
  229                 if ((*errorp = in6_embedscope(&srcsock.sin6_addr, &srcsock,
  230                     NULL, NULL)) != 0) {
  231                         return (NULL);
  232                 }
  233                 srcsock.sin6_scope_id = 0; /* XXX: ifa_ifwithaddr expects 0 */
  234                 ia6 = (struct in6_ifaddr *)ifa_ifwithaddr((struct sockaddr *)(&srcsock));
  235                 if (ia6 == NULL ||
  236                     (ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) {
  237                         *errorp = EADDRNOTAVAIL;
  238                         return (NULL);
  239                 }
  240                 pi->ipi6_addr = srcsock.sin6_addr; /* XXX: this overrides pi */
  241                 return (&ia6->ia_addr.sin6_addr);
  242         }
  243 
  244         /*
  245          * Otherwise, if the socket has already bound the source, just use it.
  246          */
  247         if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr))
  248                 return (laddr);
  249 
  250         /*
  251          * If the address is not specified, choose the best one based on
  252          * the outgoing interface and the destination address.
  253          */
  254         /* get the outgoing interface */
  255         if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp)) != 0)
  256                 return (NULL);
  257 
  258 #ifdef DIAGNOSTIC
  259         if (ifp == NULL)        /* this should not happen */
  260                 panic("in6_selectsrc: NULL ifp");
  261 #endif
  262         if (in6_addr2zoneid(ifp, dst, &odstzone)) { /* impossible */
  263                 *errorp = EIO;  /* XXX */
  264                 return (NULL);
  265         }
  266         for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
  267                 int new_scope = -1, new_matchlen = -1;
  268                 struct in6_addrpolicy *new_policy = NULL;
  269                 u_int32_t srczone, osrczone, dstzone;
  270                 struct ifnet *ifp1 = ia->ia_ifp;
  271 
  272                 /*
  273                  * We'll never take an address that breaks the scope zone
  274                  * of the destination.  We also skip an address if its zone
  275                  * does not contain the outgoing interface.
  276                  * XXX: we should probably use sin6_scope_id here.
  277                  */
  278                 if (in6_addr2zoneid(ifp1, dst, &dstzone) ||
  279                     odstzone != dstzone) {
  280                         continue;
  281                 }
  282                 if (in6_addr2zoneid(ifp, &ia->ia_addr.sin6_addr, &osrczone) ||
  283                     in6_addr2zoneid(ifp1, &ia->ia_addr.sin6_addr, &srczone) ||
  284                     osrczone != srczone) {
  285                         continue;
  286                 }
  287 
  288                 /* avoid unusable addresses */
  289                 if ((ia->ia6_flags &
  290                      (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) {
  291                                 continue;
  292                 }
  293                 if (!ip6_use_deprecated && IFA6_IS_DEPRECATED(ia))
  294                         continue;
  295 
  296                 /* Rule 1: Prefer same address */
  297                 if (IN6_ARE_ADDR_EQUAL(dst, &ia->ia_addr.sin6_addr)) {
  298                         ia_best = ia;
  299                         BREAK(1); /* there should be no better candidate */
  300                 }
  301 
  302                 if (ia_best == NULL)
  303                         REPLACE(0);
  304 
  305                 /* Rule 2: Prefer appropriate scope */
  306                 if (dst_scope < 0)
  307                         dst_scope = in6_addrscope(dst);
  308                 new_scope = in6_addrscope(&ia->ia_addr.sin6_addr);
  309                 if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) {
  310                         if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0)
  311                                 REPLACE(2);
  312                         NEXT(2);
  313                 } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) {
  314                         if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0)
  315                                 NEXT(2);
  316                         REPLACE(2);
  317                 }
  318 
  319                 /*
  320                  * Rule 3: Avoid deprecated addresses.  Note that the case of
  321                  * !ip6_use_deprecated is already rejected above.
  322                  */
  323                 if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia))
  324                         NEXT(3);
  325                 if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia))
  326                         REPLACE(3);
  327 
  328                 /* Rule 4: Prefer home addresses */
  329                 /*
  330                  * XXX: This is a TODO.  We should probably merge the MIP6
  331                  * case above.
  332                  */
  333 
  334                 /* Rule 5: Prefer outgoing interface */
  335                 if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp)
  336                         NEXT(5);
  337                 if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp)
  338                         REPLACE(5);
  339 
  340                 /*
  341                  * Rule 6: Prefer matching label
  342                  * Note that best_policy should be non-NULL here.
  343                  */
  344                 if (dst_policy == NULL)
  345                         dst_policy = lookup_addrsel_policy(dstsock);
  346                 if (dst_policy->label != ADDR_LABEL_NOTAPP) {
  347                         new_policy = lookup_addrsel_policy(&ia->ia_addr);
  348                         if (dst_policy->label == best_policy->label &&
  349                             dst_policy->label != new_policy->label)
  350                                 NEXT(6);
  351                         if (dst_policy->label != best_policy->label &&
  352                             dst_policy->label == new_policy->label)
  353                                 REPLACE(6);
  354                 }
  355 
  356                 /*
  357                  * Rule 7: Prefer public addresses.
  358                  * We allow users to reverse the logic by configuring
  359                  * a sysctl variable, so that privacy conscious users can
  360                  * always prefer temporary addresses.
  361                  */
  362                 if (opts == NULL ||
  363                     opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) {
  364                         prefer_tempaddr = ip6_prefer_tempaddr;
  365                 } else if (opts->ip6po_prefer_tempaddr ==
  366                     IP6PO_TEMPADDR_NOTPREFER) {
  367                         prefer_tempaddr = 0;
  368                 } else
  369                         prefer_tempaddr = 1;
  370                 if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
  371                     (ia->ia6_flags & IN6_IFF_TEMPORARY)) {
  372                         if (prefer_tempaddr)
  373                                 REPLACE(7);
  374                         else
  375                                 NEXT(7);
  376                 }
  377                 if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
  378                     !(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
  379                         if (prefer_tempaddr)
  380                                 NEXT(7);
  381                         else
  382                                 REPLACE(7);
  383                 }
  384 
  385                 /*
  386                  * Rule 8: prefer addresses on alive interfaces.
  387                  * This is a KAME specific rule.
  388                  */
  389                 if ((ia_best->ia_ifp->if_flags & IFF_UP) &&
  390                     !(ia->ia_ifp->if_flags & IFF_UP))
  391                         NEXT(8);
  392                 if (!(ia_best->ia_ifp->if_flags & IFF_UP) &&
  393                     (ia->ia_ifp->if_flags & IFF_UP))
  394                         REPLACE(8);
  395 
  396                 /*
  397                  * Rule 14: Use longest matching prefix.
  398                  * Note: in the address selection draft, this rule is
  399                  * documented as "Rule 8".  However, since it is also
  400                  * documented that this rule can be overridden, we assign
  401                  * a large number so that it is easy to assign smaller numbers
  402                  * to more preferred rules.
  403                  */
  404                 new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, dst);
  405                 if (best_matchlen < new_matchlen)
  406                         REPLACE(14);
  407                 if (new_matchlen < best_matchlen)
  408                         NEXT(14);
  409 
  410                 /* Rule 15 is reserved. */
  411 
  412                 /*
  413                  * Last resort: just keep the current candidate.
  414                  * Or, do we need more rules?
  415                  */
  416                 continue;
  417 
  418           replace:
  419                 ia_best = ia;
  420                 best_scope = (new_scope >= 0 ? new_scope :
  421                               in6_addrscope(&ia_best->ia_addr.sin6_addr));
  422                 best_policy = (new_policy ? new_policy :
  423                                lookup_addrsel_policy(&ia_best->ia_addr));
  424                 best_matchlen = (new_matchlen >= 0 ? new_matchlen :
  425                                  in6_matchlen(&ia_best->ia_addr.sin6_addr,
  426                                               dst));
  427 
  428           next:
  429                 continue;
  430 
  431           out:
  432                 break;
  433         }
  434 
  435         if ((ia = ia_best) == NULL) {
  436                 *errorp = EADDRNOTAVAIL;
  437                 return (NULL);
  438         }
  439 
  440         return (&ia->ia_addr.sin6_addr);
  441 }
  442 
  443 static int
  444 in6_selectif(dstsock, opts, mopts, ro, retifp)
  445         struct sockaddr_in6 *dstsock;
  446         struct ip6_pktopts *opts;
  447         struct ip6_moptions *mopts;
  448         struct route_in6 *ro;
  449         struct ifnet **retifp;
  450 {
  451         int error;
  452         struct route_in6 sro;
  453         struct rtentry *rt = NULL;
  454 
  455         if (ro == NULL) {
  456                 bzero(&sro, sizeof(sro));
  457                 ro = &sro;
  458         }
  459 
  460         if ((error = in6_selectroute(dstsock, opts, mopts, ro, retifp,
  461                                      &rt, 0)) != 0) {
  462                 if (rt && rt == sro.ro_rt)
  463                         RTFREE(rt);
  464                 return (error);
  465         }
  466 
  467         /*
  468          * do not use a rejected or black hole route.
  469          * XXX: this check should be done in the L2 output routine.
  470          * However, if we skipped this check here, we'd see the following
  471          * scenario:
  472          * - install a rejected route for a scoped address prefix
  473          *   (like fe80::/10)
  474          * - send a packet to a destination that matches the scoped prefix,
  475          *   with ambiguity about the scope zone.
  476          * - pick the outgoing interface from the route, and disambiguate the
  477          *   scope zone with the interface.
  478          * - ip6_output() would try to get another route with the "new"
  479          *   destination, which may be valid.
  480          * - we'd see no error on output.
  481          * Although this may not be very harmful, it should still be confusing.
  482          * We thus reject the case here.
  483          */
  484         if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) {
  485                 int flags = (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
  486 
  487                 if (rt && rt == sro.ro_rt)
  488                         RTFREE(rt);
  489                 return (flags);
  490         }
  491 
  492         /*
  493          * Adjust the "outgoing" interface.  If we're going to loop the packet
  494          * back to ourselves, the ifp would be the loopback interface.
  495          * However, we'd rather know the interface associated to the
  496          * destination address (which should probably be one of our own
  497          * addresses.)
  498          */
  499         if (rt && rt->rt_ifa && rt->rt_ifa->ifa_ifp)
  500                 *retifp = rt->rt_ifa->ifa_ifp;
  501 
  502         if (rt && rt == sro.ro_rt)
  503                 RTFREE(rt);
  504         return (0);
  505 }
  506 
  507 int
  508 in6_selectroute(dstsock, opts, mopts, ro, retifp, retrt, clone)
  509         struct sockaddr_in6 *dstsock;
  510         struct ip6_pktopts *opts;
  511         struct ip6_moptions *mopts;
  512         struct route_in6 *ro;
  513         struct ifnet **retifp;
  514         struct rtentry **retrt;
  515         int clone;              /* meaningful only for bsdi and freebsd. */
  516 {
  517         int error = 0;
  518         struct ifnet *ifp = NULL;
  519         struct rtentry *rt = NULL;
  520         struct sockaddr_in6 *sin6_next;
  521         struct in6_pktinfo *pi = NULL;
  522         struct in6_addr *dst = &dstsock->sin6_addr;
  523 
  524 #if 0
  525         if (dstsock->sin6_addr.s6_addr32[0] == 0 &&
  526             dstsock->sin6_addr.s6_addr32[1] == 0 &&
  527             !IN6_IS_ADDR_LOOPBACK(&dstsock->sin6_addr)) {
  528                 printf("in6_selectroute: strange destination %s\n",
  529                        ip6_sprintf(&dstsock->sin6_addr));
  530         } else {
  531                 printf("in6_selectroute: destination = %s%%%d\n",
  532                        ip6_sprintf(&dstsock->sin6_addr),
  533                        dstsock->sin6_scope_id); /* for debug */
  534         }
  535 #endif
  536 
  537         /* If the caller specify the outgoing interface explicitly, use it. */
  538         if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
  539                 /* XXX boundary check is assumed to be already done. */
  540                 ifp = ifnet_byindex(pi->ipi6_ifindex);
  541                 if (ifp != NULL &&
  542                     (retrt == NULL || IN6_IS_ADDR_MULTICAST(dst))) {
  543                         /*
  544                          * we do not have to check nor get the route for
  545                          * multicast.
  546                          */
  547                         goto done;
  548                 } else
  549                         goto getroute;
  550         }
  551 
  552         /*
  553          * If the destination address is a multicast address and the outgoing
  554          * interface for the address is specified by the caller, use it.
  555          */
  556         if (IN6_IS_ADDR_MULTICAST(dst) &&
  557             mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) {
  558                 goto done; /* we do not need a route for multicast. */
  559         }
  560 
  561   getroute:
  562         /*
  563          * If the next hop address for the packet is specified by the caller,
  564          * use it as the gateway.
  565          */
  566         if (opts && opts->ip6po_nexthop) {
  567                 struct route_in6 *ron;
  568 
  569                 sin6_next = satosin6(opts->ip6po_nexthop);
  570 
  571                 /* at this moment, we only support AF_INET6 next hops */
  572                 if (sin6_next->sin6_family != AF_INET6) {
  573                         error = EAFNOSUPPORT; /* or should we proceed? */
  574                         goto done;
  575                 }
  576 
  577                 /*
  578                  * If the next hop is an IPv6 address, then the node identified
  579                  * by that address must be a neighbor of the sending host.
  580                  */
  581                 ron = &opts->ip6po_nextroute;
  582                 if ((ron->ro_rt &&
  583                      (ron->ro_rt->rt_flags & (RTF_UP | RTF_LLINFO)) !=
  584                      (RTF_UP | RTF_LLINFO)) ||
  585                     !SA6_ARE_ADDR_EQUAL(satosin6(&ron->ro_dst), sin6_next)) {
  586                         if (ron->ro_rt) {
  587                                 RTFREE(ron->ro_rt);
  588                                 ron->ro_rt = NULL;
  589                         }
  590                         *satosin6(&ron->ro_dst) = *sin6_next;
  591                 }
  592                 if (ron->ro_rt == NULL) {
  593                         rtalloc((struct route *)ron); /* multi path case? */
  594                         if (ron->ro_rt == NULL ||
  595                             !(ron->ro_rt->rt_flags & RTF_LLINFO)) {
  596                                 if (ron->ro_rt) {
  597                                         RTFREE(ron->ro_rt);
  598                                         ron->ro_rt = NULL;
  599                                 }
  600                                 error = EHOSTUNREACH;
  601                                 goto done;
  602                         }
  603                 }
  604                 rt = ron->ro_rt;
  605                 ifp = rt->rt_ifp;
  606 
  607                 /*
  608                  * When cloning is required, try to allocate a route to the
  609                  * destination so that the caller can store path MTU
  610                  * information.
  611                  */
  612                 if (!clone)
  613                         goto done;
  614         }
  615 
  616         /*
  617          * Use a cached route if it exists and is valid, else try to allocate
  618          * a new one.  Note that we should check the address family of the
  619          * cached destination, in case of sharing the cache with IPv4.
  620          */
  621         if (ro) {
  622                 if (ro->ro_rt &&
  623                     (!(ro->ro_rt->rt_flags & RTF_UP) ||
  624                      ((struct sockaddr *)(&ro->ro_dst))->sa_family != AF_INET6 ||
  625                      !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr,
  626                                          dst))) {
  627                         RTFREE(ro->ro_rt);
  628                         ro->ro_rt = (struct rtentry *)NULL;
  629                 }
  630                 if (ro->ro_rt == (struct rtentry *)NULL) {
  631                         struct sockaddr_in6 *sa6;
  632 
  633                         /* No route yet, so try to acquire one */
  634                         bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
  635                         sa6 = (struct sockaddr_in6 *)&ro->ro_dst;
  636                         *sa6 = *dstsock;
  637                         sa6->sin6_scope_id = 0;
  638 
  639                         if (clone) {
  640                                 rtalloc((struct route *)ro);
  641                         } else {
  642                                 ro->ro_rt = rtalloc1(&((struct route *)ro)
  643                                                      ->ro_dst, NULL, 0UL);
  644                                 if (ro->ro_rt)
  645                                         RT_UNLOCK(ro->ro_rt);
  646                         }
  647                 }
  648 
  649                 /*
  650                  * do not care about the result if we have the nexthop
  651                  * explicitly specified.
  652                  */
  653                 if (opts && opts->ip6po_nexthop)
  654                         goto done;
  655 
  656                 if (ro->ro_rt) {
  657                         ifp = ro->ro_rt->rt_ifp;
  658 
  659                         if (ifp == NULL) { /* can this really happen? */
  660                                 RTFREE(ro->ro_rt);
  661                                 ro->ro_rt = NULL;
  662                         }
  663                 }
  664                 if (ro->ro_rt == NULL)
  665                         error = EHOSTUNREACH;
  666                 rt = ro->ro_rt;
  667 
  668                 /*
  669                  * Check if the outgoing interface conflicts with
  670                  * the interface specified by ipi6_ifindex (if specified).
  671                  * Note that loopback interface is always okay.
  672                  * (this may happen when we are sending a packet to one of
  673                  *  our own addresses.)
  674                  */
  675                 if (opts && opts->ip6po_pktinfo
  676                     && opts->ip6po_pktinfo->ipi6_ifindex) {
  677                         if (!(ifp->if_flags & IFF_LOOPBACK) &&
  678                             ifp->if_index !=
  679                             opts->ip6po_pktinfo->ipi6_ifindex) {
  680                                 error = EHOSTUNREACH;
  681                                 goto done;
  682                         }
  683                 }
  684         }
  685 
  686   done:
  687         if (ifp == NULL && rt == NULL) {
  688                 /*
  689                  * This can happen if the caller did not pass a cached route
  690                  * nor any other hints.  We treat this case an error.
  691                  */
  692                 error = EHOSTUNREACH;
  693         }
  694         if (error == EHOSTUNREACH)
  695                 ip6stat.ip6s_noroute++;
  696 
  697         if (retifp != NULL)
  698                 *retifp = ifp;
  699         if (retrt != NULL)
  700                 *retrt = rt;    /* rt may be NULL */
  701 
  702         return (error);
  703 }
  704 
  705 /*
  706  * Default hop limit selection. The precedence is as follows:
  707  * 1. Hoplimit value specified via ioctl.
  708  * 2. (If the outgoing interface is detected) the current
  709  *     hop limit of the interface specified by router advertisement.
  710  * 3. The system default hoplimit.
  711  */
  712 int
  713 in6_selecthlim(in6p, ifp)
  714         struct in6pcb *in6p;
  715         struct ifnet *ifp;
  716 {
  717         if (in6p && in6p->in6p_hops >= 0)
  718                 return (in6p->in6p_hops);
  719         else if (ifp)
  720                 return (ND_IFINFO(ifp)->chlim);
  721         else if (in6p && !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
  722                 struct route_in6 ro6;
  723                 struct ifnet *lifp;
  724 
  725                 bzero(&ro6, sizeof(ro6));
  726                 ro6.ro_dst.sin6_family = AF_INET6;
  727                 ro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
  728                 ro6.ro_dst.sin6_addr = in6p->in6p_faddr;
  729                 rtalloc((struct route *)&ro6);
  730                 if (ro6.ro_rt) {
  731                         lifp = ro6.ro_rt->rt_ifp;
  732                         RTFREE(ro6.ro_rt);
  733                         if (lifp)
  734                                 return (ND_IFINFO(lifp)->chlim);
  735                 } else
  736                         return (ip6_defhlim);
  737         }
  738         return (ip6_defhlim);
  739 }
  740 
  741 /*
  742  * XXX: this is borrowed from in6_pcbbind(). If possible, we should
  743  * share this function by all *bsd*...
  744  */
  745 int
  746 in6_pcbsetport(laddr, inp, td)
  747         struct in6_addr *laddr;
  748         struct inpcb *inp;
  749         struct thread *td;
  750 {
  751         struct socket *so = inp->inp_socket;
  752         u_int16_t lport = 0, first, last, *lastport;
  753         int count, error = 0, wild = 0;
  754         struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
  755 
  756         /* XXX: this is redundant when called from in6_pcbbind */
  757         if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0)
  758                 wild = INPLOOKUP_WILDCARD;
  759 
  760         inp->inp_flags |= INP_ANONPORT;
  761 
  762         if (inp->inp_flags & INP_HIGHPORT) {
  763                 first = ipport_hifirstauto;     /* sysctl */
  764                 last  = ipport_hilastauto;
  765                 lastport = &pcbinfo->lasthi;
  766         } else if (inp->inp_flags & INP_LOWPORT) {
  767                 if (td && (error = suser(td)))
  768                         return error;
  769                 first = ipport_lowfirstauto;    /* 1023 */
  770                 last  = ipport_lowlastauto;     /* 600 */
  771                 lastport = &pcbinfo->lastlow;
  772         } else {
  773                 first = ipport_firstauto;       /* sysctl */
  774                 last  = ipport_lastauto;
  775                 lastport = &pcbinfo->lastport;
  776         }
  777         /*
  778          * Simple check to ensure all ports are not used up causing
  779          * a deadlock here.
  780          *
  781          * We split the two cases (up and down) so that the direction
  782          * is not being tested on each round of the loop.
  783          */
  784         if (first > last) {
  785                 /*
  786                  * counting down
  787                  */
  788                 count = first - last;
  789 
  790                 do {
  791                         if (count-- < 0) {      /* completely used? */
  792                                 /*
  793                                  * Undo any address bind that may have
  794                                  * occurred above.
  795                                  */
  796                                 inp->in6p_laddr = in6addr_any;
  797                                 return (EAGAIN);
  798                         }
  799                         --*lastport;
  800                         if (*lastport > first || *lastport < last)
  801                                 *lastport = first;
  802                         lport = htons(*lastport);
  803                 } while (in6_pcblookup_local(pcbinfo,
  804                                              &inp->in6p_laddr, lport, wild));
  805         } else {
  806                 /*
  807                          * counting up
  808                          */
  809                 count = last - first;
  810 
  811                 do {
  812                         if (count-- < 0) {      /* completely used? */
  813                                 /*
  814                                  * Undo any address bind that may have
  815                                  * occurred above.
  816                                  */
  817                                 inp->in6p_laddr = in6addr_any;
  818                                 return (EAGAIN);
  819                         }
  820                         ++*lastport;
  821                         if (*lastport < first || *lastport > last)
  822                                 *lastport = first;
  823                         lport = htons(*lastport);
  824                 } while (in6_pcblookup_local(pcbinfo,
  825                                              &inp->in6p_laddr, lport, wild));
  826         }
  827 
  828         inp->inp_lport = lport;
  829         if (in_pcbinshash(inp) != 0) {
  830                 inp->in6p_laddr = in6addr_any;
  831                 inp->inp_lport = 0;
  832                 return (EAGAIN);
  833         }
  834 
  835         return (0);
  836 }
  837 
  838 /*
  839  * Generate kernel-internal form (scopeid embedded into s6_addr16[1]).
  840  * If the address scope of is link-local, embed the interface index in the
  841  * address.  The routine determines our precedence
  842  * between advanced API scope/interface specification and basic API
  843  * specification.
  844  *
  845  * This function should be nuked in the future, when we get rid of embedded
  846  * scopeid thing.
  847  *
  848  * XXX actually, it is over-specification to return ifp against sin6_scope_id.
  849  * there can be multiple interfaces that belong to a particular scope zone
  850  * (in specification, we have 1:N mapping between a scope zone and interfaces).
  851  * we may want to change the function to return something other than ifp.
  852  */
  853 int
  854 in6_embedscope(in6, sin6, in6p, ifpp)
  855         struct in6_addr *in6;
  856         const struct sockaddr_in6 *sin6;
  857         struct in6pcb *in6p;
  858         struct ifnet **ifpp;
  859 {
  860         struct ifnet *ifp = NULL;
  861         u_int32_t zoneid = sin6->sin6_scope_id;
  862 
  863         *in6 = sin6->sin6_addr;
  864         if (ifpp)
  865                 *ifpp = NULL;
  866 
  867         /*
  868          * don't try to read sin6->sin6_addr beyond here, since the caller may
  869          * ask us to overwrite existing sockaddr_in6
  870          */
  871 
  872 #ifdef ENABLE_DEFAULT_SCOPE
  873         if (zoneid == 0)
  874                 zoneid = scope6_addr2default(in6);
  875 #endif
  876 
  877         if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6)) {
  878                 struct in6_pktinfo *pi;
  879 
  880                 /* KAME assumption: link id == interface id */
  881                 if (in6p && in6p->in6p_outputopts &&
  882                     (pi = in6p->in6p_outputopts->ip6po_pktinfo) &&
  883                     pi->ipi6_ifindex) {
  884                         ifp = ifnet_byindex(pi->ipi6_ifindex);
  885                         in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
  886                 } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
  887                            in6p->in6p_moptions &&
  888                            in6p->in6p_moptions->im6o_multicast_ifp) {
  889                         ifp = in6p->in6p_moptions->im6o_multicast_ifp;
  890                         in6->s6_addr16[1] = htons(ifp->if_index);
  891                 } else if (zoneid) {
  892                         if (if_index < zoneid)
  893                                 return (ENXIO);  /* XXX EINVAL? */
  894                         ifp = ifnet_byindex(zoneid);
  895 
  896                         /* XXX assignment to 16bit from 32bit variable */
  897                         in6->s6_addr16[1] = htons(zoneid & 0xffff);
  898                 }
  899 
  900                 if (ifpp)
  901                         *ifpp = ifp;
  902         }
  903 
  904         return 0;
  905 }
  906 
  907 /*
  908  * generate standard sockaddr_in6 from embedded form.
  909  * touches sin6_addr and sin6_scope_id only.
  910  *
  911  * this function should be nuked in the future, when we get rid of
  912  * embedded scopeid thing.
  913  */
  914 int
  915 in6_recoverscope(sin6, in6, ifp)
  916         struct sockaddr_in6 *sin6;
  917         const struct in6_addr *in6;
  918         struct ifnet *ifp;
  919 {
  920         u_int32_t zoneid;
  921 
  922         sin6->sin6_addr = *in6;
  923 
  924         /*
  925          * don't try to read *in6 beyond here, since the caller may
  926          * ask us to overwrite existing sockaddr_in6
  927          */
  928 
  929         sin6->sin6_scope_id = 0;
  930         if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6)) {
  931                 /*
  932                  * KAME assumption: link id == interface id
  933                  */
  934                 zoneid = ntohs(sin6->sin6_addr.s6_addr16[1]);
  935                 if (zoneid) {
  936                         /* sanity check */
  937                         if (zoneid < 0 || if_index < zoneid)
  938                                 return ENXIO;
  939                         if (ifp && ifp->if_index != zoneid)
  940                                 return ENXIO;
  941                         sin6->sin6_addr.s6_addr16[1] = 0;
  942                         sin6->sin6_scope_id = zoneid;
  943                 }
  944         }
  945 
  946         return 0;
  947 }
  948 
  949 /*
  950  * just clear the embedded scope identifier.
  951  */
  952 void
  953 in6_clearscope(addr)
  954         struct in6_addr *addr;
  955 {
  956         if (IN6_IS_SCOPE_LINKLOCAL(addr) || IN6_IS_ADDR_MC_INTFACELOCAL(addr))
  957                 addr->s6_addr16[1] = 0;
  958 }
  959 
  960 void
  961 addrsel_policy_init()
  962 {
  963         ADDRSEL_LOCK_INIT();
  964 
  965         init_policy_queue();
  966 
  967         /* initialize the "last resort" policy */
  968         bzero(&defaultaddrpolicy, sizeof(defaultaddrpolicy));
  969         defaultaddrpolicy.label = ADDR_LABEL_NOTAPP;
  970 }
  971 
  972 static struct in6_addrpolicy *
  973 lookup_addrsel_policy(key)
  974         struct sockaddr_in6 *key;
  975 {
  976         struct in6_addrpolicy *match = NULL;
  977 
  978         ADDRSEL_LOCK();
  979         match = match_addrsel_policy(key);
  980 
  981         if (match == NULL)
  982                 match = &defaultaddrpolicy;
  983         else
  984                 match->use++;
  985         ADDRSEL_UNLOCK();
  986 
  987         return (match);
  988 }
  989 
  990 /*
  991  * Subroutines to manage the address selection policy table via sysctl.
  992  */
  993 struct walkarg {
  994         struct sysctl_req *w_req;
  995 };
  996 
  997 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS);
  998 SYSCTL_DECL(_net_inet6_ip6);
  999 SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy,
 1000         CTLFLAG_RD, in6_src_sysctl, "");
 1001 
 1002 static int
 1003 in6_src_sysctl(SYSCTL_HANDLER_ARGS)
 1004 {
 1005         struct walkarg w;
 1006 
 1007         if (req->newptr)
 1008                 return EPERM;
 1009 
 1010         bzero(&w, sizeof(w));
 1011         w.w_req = req;
 1012 
 1013         return (walk_addrsel_policy(dump_addrsel_policyent, &w));
 1014 }
 1015 
 1016 int
 1017 in6_src_ioctl(cmd, data)
 1018         u_long cmd;
 1019         caddr_t data;
 1020 {
 1021         int i;
 1022         struct in6_addrpolicy ent0;
 1023 
 1024         if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY)
 1025                 return (EOPNOTSUPP); /* check for safety */
 1026 
 1027         ent0 = *(struct in6_addrpolicy *)data;
 1028 
 1029         if (ent0.label == ADDR_LABEL_NOTAPP)
 1030                 return (EINVAL);
 1031         /* check if the prefix mask is consecutive. */
 1032         if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0)
 1033                 return (EINVAL);
 1034         /* clear trailing garbages (if any) of the prefix address. */
 1035         for (i = 0; i < 4; i++) {
 1036                 ent0.addr.sin6_addr.s6_addr32[i] &=
 1037                         ent0.addrmask.sin6_addr.s6_addr32[i];
 1038         }
 1039         ent0.use = 0;
 1040 
 1041         switch (cmd) {
 1042         case SIOCAADDRCTL_POLICY:
 1043                 return (add_addrsel_policyent(&ent0));
 1044         case SIOCDADDRCTL_POLICY:
 1045                 return (delete_addrsel_policyent(&ent0));
 1046         }
 1047 
 1048         return (0);             /* XXX: compromise compilers */
 1049 }
 1050 
 1051 /*
 1052  * The followings are implementation of the policy table using a
 1053  * simple tail queue.
 1054  * XXX such details should be hidden.
 1055  * XXX implementation using binary tree should be more efficient.
 1056  */
 1057 struct addrsel_policyent {
 1058         TAILQ_ENTRY(addrsel_policyent) ape_entry;
 1059         struct in6_addrpolicy ape_policy;
 1060 };
 1061 
 1062 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent);
 1063 
 1064 struct addrsel_policyhead addrsel_policytab;
 1065 
 1066 static void
 1067 init_policy_queue()
 1068 {
 1069         TAILQ_INIT(&addrsel_policytab);
 1070 }
 1071 
 1072 static int
 1073 add_addrsel_policyent(newpolicy)
 1074         struct in6_addrpolicy *newpolicy;
 1075 {
 1076         struct addrsel_policyent *new, *pol;
 1077 
 1078         MALLOC(new, struct addrsel_policyent *, sizeof(*new), M_IFADDR,
 1079                M_WAITOK);
 1080         ADDRSEL_LOCK();
 1081 
 1082         /* duplication check */
 1083         for (pol = TAILQ_FIRST(&addrsel_policytab); pol;
 1084              pol = TAILQ_NEXT(pol, ape_entry)) {
 1085                 if (SA6_ARE_ADDR_EQUAL(&newpolicy->addr,
 1086                                        &pol->ape_policy.addr) &&
 1087                     SA6_ARE_ADDR_EQUAL(&newpolicy->addrmask,
 1088                                        &pol->ape_policy.addrmask)) {
 1089                         ADDRSEL_UNLOCK();
 1090                         FREE(new, M_IFADDR);
 1091                         return (EEXIST);        /* or override it? */
 1092                 }
 1093         }
 1094 
 1095         bzero(new, sizeof(*new));
 1096 
 1097         /* XXX: should validate entry */
 1098         new->ape_policy = *newpolicy;
 1099 
 1100         TAILQ_INSERT_TAIL(&addrsel_policytab, new, ape_entry);
 1101         ADDRSEL_UNLOCK();
 1102 
 1103         return (0);
 1104 }
 1105 
 1106 static int
 1107 delete_addrsel_policyent(key)
 1108         struct in6_addrpolicy *key;
 1109 {
 1110         struct addrsel_policyent *pol;
 1111 
 1112         ADDRSEL_LOCK();
 1113 
 1114         /* search for the entry in the table */
 1115         for (pol = TAILQ_FIRST(&addrsel_policytab); pol;
 1116              pol = TAILQ_NEXT(pol, ape_entry)) {
 1117                 if (SA6_ARE_ADDR_EQUAL(&key->addr, &pol->ape_policy.addr) &&
 1118                     SA6_ARE_ADDR_EQUAL(&key->addrmask,
 1119                                        &pol->ape_policy.addrmask)) {
 1120                         break;
 1121                 }
 1122         }
 1123         if (pol == NULL) {
 1124                 ADDRSEL_UNLOCK();
 1125                 return (ESRCH);
 1126         }
 1127 
 1128         TAILQ_REMOVE(&addrsel_policytab, pol, ape_entry);
 1129         ADDRSEL_UNLOCK();
 1130 
 1131         return (0);
 1132 }
 1133 
 1134 static int
 1135 walk_addrsel_policy(callback, w)
 1136         int (*callback) __P((struct in6_addrpolicy *, void *));
 1137         void *w;
 1138 {
 1139         struct addrsel_policyent *pol;
 1140         int error = 0;
 1141 
 1142         ADDRSEL_LOCK();
 1143         for (pol = TAILQ_FIRST(&addrsel_policytab); pol;
 1144              pol = TAILQ_NEXT(pol, ape_entry)) {
 1145                 if ((error = (*callback)(&pol->ape_policy, w)) != 0) {
 1146                         ADDRSEL_UNLOCK();
 1147                         return (error);
 1148                 }
 1149         }
 1150         ADDRSEL_UNLOCK();
 1151 
 1152         return (error);
 1153 }
 1154 
 1155 static int
 1156 dump_addrsel_policyent(pol, arg)
 1157         struct in6_addrpolicy *pol;
 1158         void *arg;
 1159 {
 1160         int error = 0;
 1161         struct walkarg *w = arg;
 1162 
 1163         error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol));
 1164 
 1165         return (error);
 1166 }
 1167 
 1168 static struct in6_addrpolicy *
 1169 match_addrsel_policy(key)
 1170         struct sockaddr_in6 *key;
 1171 {
 1172         struct addrsel_policyent *pent;
 1173         struct in6_addrpolicy *bestpol = NULL, *pol;
 1174         int matchlen, bestmatchlen = -1;
 1175         u_char *mp, *ep, *k, *p, m;
 1176 
 1177         for (pent = TAILQ_FIRST(&addrsel_policytab); pent;
 1178              pent = TAILQ_NEXT(pent, ape_entry)) {
 1179                 matchlen = 0;
 1180 
 1181                 pol = &pent->ape_policy;
 1182                 mp = (u_char *)&pol->addrmask.sin6_addr;
 1183                 ep = mp + 16;   /* XXX: scope field? */
 1184                 k = (u_char *)&key->sin6_addr;
 1185                 p = (u_char *)&pol->addr.sin6_addr;
 1186                 for (; mp < ep && *mp; mp++, k++, p++) {
 1187                         m = *mp;
 1188                         if ((*k & m) != *p)
 1189                                 goto next; /* not match */
 1190                         if (m == 0xff) /* short cut for a typical case */
 1191                                 matchlen += 8;
 1192                         else {
 1193                                 while (m >= 0x80) {
 1194                                         matchlen++;
 1195                                         m <<= 1;
 1196                                 }
 1197                         }
 1198                 }
 1199 
 1200                 /* matched.  check if this is better than the current best. */
 1201                 if (bestpol == NULL ||
 1202                     matchlen > bestmatchlen) {
 1203                         bestpol = pol;
 1204                         bestmatchlen = matchlen;
 1205                 }
 1206 
 1207           next:
 1208                 continue;
 1209         }
 1210 
 1211         return (bestpol);
 1212 }

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