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/6.1/sys/netinet6/in6_src.c 158179 2006-04-30 16:44:43Z cvs2svn $       */
    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  * 4. Neither the name of the University nor the names of its contributors
   46  *    may be used to endorse or promote products derived from this software
   47  *    without specific prior written permission.
   48  *
   49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   59  * SUCH DAMAGE.
   60  *
   61  *      @(#)in_pcb.c    8.2 (Berkeley) 1/4/94
   62  */
   63 
   64 #include "opt_inet.h"
   65 #include "opt_inet6.h"
   66 
   67 #include <sys/param.h>
   68 #include <sys/systm.h>
   69 #include <sys/malloc.h>
   70 #include <sys/mbuf.h>
   71 #include <sys/protosw.h>
   72 #include <sys/socket.h>
   73 #include <sys/socketvar.h>
   74 #include <sys/sockio.h>
   75 #include <sys/sysctl.h>
   76 #include <sys/errno.h>
   77 #include <sys/time.h>
   78 #include <sys/kernel.h>
   79 #include <sys/sx.h>
   80 
   81 #include <net/if.h>
   82 #include <net/route.h>
   83 
   84 #include <netinet/in.h>
   85 #include <netinet/in_var.h>
   86 #include <netinet/in_systm.h>
   87 #include <netinet/ip.h>
   88 #include <netinet/in_pcb.h>
   89 #include <netinet6/in6_var.h>
   90 #include <netinet/ip6.h>
   91 #include <netinet6/in6_pcb.h>
   92 #include <netinet6/ip6_var.h>
   93 #include <netinet6/scope6_var.h>
   94 #include <netinet6/nd6.h>
   95 
   96 #include <net/net_osdep.h>
   97 
   98 static struct mtx addrsel_lock;
   99 #define ADDRSEL_LOCK_INIT()     mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF)
  100 #define ADDRSEL_LOCK()          mtx_lock(&addrsel_lock)
  101 #define ADDRSEL_UNLOCK()        mtx_unlock(&addrsel_lock)
  102 #define ADDRSEL_LOCK_ASSERT()   mtx_assert(&addrsel_lock, MA_OWNED)
  103 
  104 static struct sx addrsel_sxlock;
  105 #define ADDRSEL_SXLOCK_INIT()   sx_init(&addrsel_sxlock, "addrsel_sxlock")
  106 #define ADDRSEL_SLOCK()         sx_slock(&addrsel_sxlock)
  107 #define ADDRSEL_SUNLOCK()       sx_sunlock(&addrsel_sxlock)
  108 #define ADDRSEL_XLOCK()         sx_xlock(&addrsel_sxlock)
  109 #define ADDRSEL_XUNLOCK()       sx_xunlock(&addrsel_sxlock)
  110 
  111 #define ADDR_LABEL_NOTAPP (-1)
  112 struct in6_addrpolicy defaultaddrpolicy;
  113 
  114 int ip6_prefer_tempaddr = 0;
  115 
  116 static int selectroute __P((struct sockaddr_in6 *, struct ip6_pktopts *,
  117         struct ip6_moptions *, struct route_in6 *, struct ifnet **,
  118         struct rtentry **, int, int));
  119 static int in6_selectif __P((struct sockaddr_in6 *, struct ip6_pktopts *,
  120         struct ip6_moptions *, struct route_in6 *ro, struct ifnet **));
  121 
  122 static struct in6_addrpolicy *lookup_addrsel_policy __P((struct sockaddr_in6 *));
  123 
  124 static void init_policy_queue __P((void));
  125 static int add_addrsel_policyent __P((struct in6_addrpolicy *));
  126 static int delete_addrsel_policyent __P((struct in6_addrpolicy *));
  127 static int walk_addrsel_policy __P((int (*)(struct in6_addrpolicy *, void *),
  128                                     void *));
  129 static int dump_addrsel_policyent __P((struct in6_addrpolicy *, void *));
  130 static struct in6_addrpolicy *match_addrsel_policy __P((struct sockaddr_in6 *));
  131 
  132 /*
  133  * Return an IPv6 address, which is the most appropriate for a given
  134  * destination and user specified options.
  135  * If necessary, this function lookups the routing table and returns
  136  * an entry to the caller for later use.
  137  */
  138 #define REPLACE(r) do {\
  139         if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \
  140                 sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
  141                 ip6stat.ip6s_sources_rule[(r)]++; \
  142         /* 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)); */ \
  143         goto replace; \
  144 } while(0)
  145 #define NEXT(r) do {\
  146         if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \
  147                 sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
  148                 ip6stat.ip6s_sources_rule[(r)]++; \
  149         /* 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)); */ \
  150         goto next;              /* XXX: we can't use 'continue' here */ \
  151 } while(0)
  152 #define BREAK(r) do { \
  153         if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \
  154                 sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
  155                 ip6stat.ip6s_sources_rule[(r)]++; \
  156         goto out;               /* XXX: we can't use 'break' here */ \
  157 } while(0)
  158 
  159 struct in6_addr *
  160 in6_selectsrc(dstsock, opts, mopts, ro, laddr, ifpp, errorp)
  161         struct sockaddr_in6 *dstsock;
  162         struct ip6_pktopts *opts;
  163         struct ip6_moptions *mopts;
  164         struct route_in6 *ro;
  165         struct in6_addr *laddr;
  166         struct ifnet **ifpp;
  167         int *errorp;
  168 {
  169         struct in6_addr dst;
  170         struct ifnet *ifp = NULL;
  171         struct in6_ifaddr *ia = NULL, *ia_best = NULL;
  172         struct in6_pktinfo *pi = NULL;
  173         int dst_scope = -1, best_scope = -1, best_matchlen = -1;
  174         struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL;
  175         u_int32_t odstzone;
  176         int prefer_tempaddr;
  177 
  178         dst = dstsock->sin6_addr; /* make a copy for local operation */
  179         *errorp = 0;
  180         if (ifpp)
  181                 *ifpp = NULL;
  182 
  183         /*
  184          * If the source address is explicitly specified by the caller,
  185          * check if the requested source address is indeed a unicast address
  186          * assigned to the node, and can be used as the packet's source
  187          * address.  If everything is okay, use the address as source.
  188          */
  189         if (opts && (pi = opts->ip6po_pktinfo) &&
  190             !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
  191                 struct sockaddr_in6 srcsock;
  192                 struct in6_ifaddr *ia6;
  193 
  194                 /* get the outgoing interface */
  195                 if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp))
  196                     != 0) {
  197                         return (NULL);
  198                 }
  199 
  200                 /*
  201                  * determine the appropriate zone id of the source based on
  202                  * the zone of the destination and the outgoing interface.
  203                  * If the specified address is ambiguous wrt the scope zone,
  204                  * the interface must be specified; otherwise, ifa_ifwithaddr()
  205                  * will fail matching the address.
  206                  */
  207                 bzero(&srcsock, sizeof(srcsock));
  208                 srcsock.sin6_family = AF_INET6;
  209                 srcsock.sin6_len = sizeof(srcsock);
  210                 srcsock.sin6_addr = pi->ipi6_addr;
  211                 if (ifp) {
  212                         *errorp = in6_setscope(&srcsock.sin6_addr, ifp, NULL);
  213                         if (*errorp != 0)
  214                                 return (NULL);
  215                 }
  216 
  217                 ia6 = (struct in6_ifaddr *)ifa_ifwithaddr((struct sockaddr *)(&srcsock));
  218                 if (ia6 == NULL ||
  219                     (ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) {
  220                         *errorp = EADDRNOTAVAIL;
  221                         return (NULL);
  222                 }
  223                 pi->ipi6_addr = srcsock.sin6_addr; /* XXX: this overrides pi */
  224                 if (ifpp)
  225                         *ifpp = ifp;
  226                 return (&ia6->ia_addr.sin6_addr);
  227         }
  228 
  229         /*
  230          * Otherwise, if the socket has already bound the source, just use it.
  231          */
  232         if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr))
  233                 return (laddr);
  234 
  235         /*
  236          * If the address is not specified, choose the best one based on
  237          * the outgoing interface and the destination address.
  238          */
  239         /* get the outgoing interface */
  240         if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp)) != 0)
  241                 return (NULL);
  242 
  243 #ifdef DIAGNOSTIC
  244         if (ifp == NULL)        /* this should not happen */
  245                 panic("in6_selectsrc: NULL ifp");
  246 #endif
  247         *errorp = in6_setscope(&dst, ifp, &odstzone);
  248         if (*errorp != 0)
  249                 return (NULL);
  250 
  251         for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
  252                 int new_scope = -1, new_matchlen = -1;
  253                 struct in6_addrpolicy *new_policy = NULL;
  254                 u_int32_t srczone, osrczone, dstzone;
  255                 struct in6_addr src;
  256                 struct ifnet *ifp1 = ia->ia_ifp;
  257 
  258                 /*
  259                  * We'll never take an address that breaks the scope zone
  260                  * of the destination.  We also skip an address if its zone
  261                  * does not contain the outgoing interface.
  262                  * XXX: we should probably use sin6_scope_id here.
  263                  */
  264                 if (in6_setscope(&dst, ifp1, &dstzone) ||
  265                     odstzone != dstzone) {
  266                         continue;
  267                 }
  268                 src = ia->ia_addr.sin6_addr;
  269                 if (in6_setscope(&src, ifp, &osrczone) ||
  270                     in6_setscope(&src, ifp1, &srczone) ||
  271                     osrczone != srczone) {
  272                         continue;
  273                 }
  274 
  275                 /* avoid unusable addresses */
  276                 if ((ia->ia6_flags &
  277                      (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) {
  278                                 continue;
  279                 }
  280                 if (!ip6_use_deprecated && IFA6_IS_DEPRECATED(ia))
  281                         continue;
  282 
  283                 /* Rule 1: Prefer same address */
  284                 if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) {
  285                         ia_best = ia;
  286                         BREAK(1); /* there should be no better candidate */
  287                 }
  288 
  289                 if (ia_best == NULL)
  290                         REPLACE(0);
  291 
  292                 /* Rule 2: Prefer appropriate scope */
  293                 if (dst_scope < 0)
  294                         dst_scope = in6_addrscope(&dst);
  295                 new_scope = in6_addrscope(&ia->ia_addr.sin6_addr);
  296                 if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) {
  297                         if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0)
  298                                 REPLACE(2);
  299                         NEXT(2);
  300                 } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) {
  301                         if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0)
  302                                 NEXT(2);
  303                         REPLACE(2);
  304                 }
  305 
  306                 /*
  307                  * Rule 3: Avoid deprecated addresses.  Note that the case of
  308                  * !ip6_use_deprecated is already rejected above.
  309                  */
  310                 if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia))
  311                         NEXT(3);
  312                 if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia))
  313                         REPLACE(3);
  314 
  315                 /* Rule 4: Prefer home addresses */
  316                 /*
  317                  * XXX: This is a TODO.  We should probably merge the MIP6
  318                  * case above.
  319                  */
  320 
  321                 /* Rule 5: Prefer outgoing interface */
  322                 if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp)
  323                         NEXT(5);
  324                 if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp)
  325                         REPLACE(5);
  326 
  327                 /*
  328                  * Rule 6: Prefer matching label
  329                  * Note that best_policy should be non-NULL here.
  330                  */
  331                 if (dst_policy == NULL)
  332                         dst_policy = lookup_addrsel_policy(dstsock);
  333                 if (dst_policy->label != ADDR_LABEL_NOTAPP) {
  334                         new_policy = lookup_addrsel_policy(&ia->ia_addr);
  335                         if (dst_policy->label == best_policy->label &&
  336                             dst_policy->label != new_policy->label)
  337                                 NEXT(6);
  338                         if (dst_policy->label != best_policy->label &&
  339                             dst_policy->label == new_policy->label)
  340                                 REPLACE(6);
  341                 }
  342 
  343                 /*
  344                  * Rule 7: Prefer public addresses.
  345                  * We allow users to reverse the logic by configuring
  346                  * a sysctl variable, so that privacy conscious users can
  347                  * always prefer temporary addresses.
  348                  */
  349                 if (opts == NULL ||
  350                     opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) {
  351                         prefer_tempaddr = ip6_prefer_tempaddr;
  352                 } else if (opts->ip6po_prefer_tempaddr ==
  353                     IP6PO_TEMPADDR_NOTPREFER) {
  354                         prefer_tempaddr = 0;
  355                 } else
  356                         prefer_tempaddr = 1;
  357                 if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
  358                     (ia->ia6_flags & IN6_IFF_TEMPORARY)) {
  359                         if (prefer_tempaddr)
  360                                 REPLACE(7);
  361                         else
  362                                 NEXT(7);
  363                 }
  364                 if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
  365                     !(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
  366                         if (prefer_tempaddr)
  367                                 NEXT(7);
  368                         else
  369                                 REPLACE(7);
  370                 }
  371 
  372                 /*
  373                  * Rule 8: prefer addresses on alive interfaces.
  374                  * This is a KAME specific rule.
  375                  */
  376                 if ((ia_best->ia_ifp->if_flags & IFF_UP) &&
  377                     !(ia->ia_ifp->if_flags & IFF_UP))
  378                         NEXT(8);
  379                 if (!(ia_best->ia_ifp->if_flags & IFF_UP) &&
  380                     (ia->ia_ifp->if_flags & IFF_UP))
  381                         REPLACE(8);
  382 
  383                 /*
  384                  * Rule 14: Use longest matching prefix.
  385                  * Note: in the address selection draft, this rule is
  386                  * documented as "Rule 8".  However, since it is also
  387                  * documented that this rule can be overridden, we assign
  388                  * a large number so that it is easy to assign smaller numbers
  389                  * to more preferred rules.
  390                  */
  391                 new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst);
  392                 if (best_matchlen < new_matchlen)
  393                         REPLACE(14);
  394                 if (new_matchlen < best_matchlen)
  395                         NEXT(14);
  396 
  397                 /* Rule 15 is reserved. */
  398 
  399                 /*
  400                  * Last resort: just keep the current candidate.
  401                  * Or, do we need more rules?
  402                  */
  403                 continue;
  404 
  405           replace:
  406                 ia_best = ia;
  407                 best_scope = (new_scope >= 0 ? new_scope :
  408                               in6_addrscope(&ia_best->ia_addr.sin6_addr));
  409                 best_policy = (new_policy ? new_policy :
  410                                lookup_addrsel_policy(&ia_best->ia_addr));
  411                 best_matchlen = (new_matchlen >= 0 ? new_matchlen :
  412                                  in6_matchlen(&ia_best->ia_addr.sin6_addr,
  413                                               &dst));
  414 
  415           next:
  416                 continue;
  417 
  418           out:
  419                 break;
  420         }
  421 
  422         if ((ia = ia_best) == NULL) {
  423                 *errorp = EADDRNOTAVAIL;
  424                 return (NULL);
  425         }
  426 
  427         if (ifpp)
  428                 *ifpp = ifp;
  429 
  430         return (&ia->ia_addr.sin6_addr);
  431 }
  432 
  433 static int
  434 selectroute(dstsock, opts, mopts, ro, retifp, retrt, clone, norouteok)
  435         struct sockaddr_in6 *dstsock;
  436         struct ip6_pktopts *opts;
  437         struct ip6_moptions *mopts;
  438         struct route_in6 *ro;
  439         struct ifnet **retifp;
  440         struct rtentry **retrt;
  441         int clone;              /* meaningful only for bsdi and freebsd. */
  442         int norouteok;
  443 {
  444         int error = 0;
  445         struct ifnet *ifp = NULL;
  446         struct rtentry *rt = NULL;
  447         struct sockaddr_in6 *sin6_next;
  448         struct in6_pktinfo *pi = NULL;
  449         struct in6_addr *dst = &dstsock->sin6_addr;
  450 
  451 #if 0
  452         if (dstsock->sin6_addr.s6_addr32[0] == 0 &&
  453             dstsock->sin6_addr.s6_addr32[1] == 0 &&
  454             !IN6_IS_ADDR_LOOPBACK(&dstsock->sin6_addr)) {
  455                 printf("in6_selectroute: strange destination %s\n",
  456                        ip6_sprintf(&dstsock->sin6_addr));
  457         } else {
  458                 printf("in6_selectroute: destination = %s%%%d\n",
  459                        ip6_sprintf(&dstsock->sin6_addr),
  460                        dstsock->sin6_scope_id); /* for debug */
  461         }
  462 #endif
  463 
  464         /* If the caller specify the outgoing interface explicitly, use it. */
  465         if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
  466                 /* XXX boundary check is assumed to be already done. */
  467                 ifp = ifnet_byindex(pi->ipi6_ifindex);
  468                 if (ifp != NULL &&
  469                     (norouteok || retrt == NULL ||
  470                     IN6_IS_ADDR_MULTICAST(dst))) {
  471                         /*
  472                          * we do not have to check or get the route for
  473                          * multicast.
  474                          */
  475                         goto done;
  476                 } else
  477                         goto getroute;
  478         }
  479 
  480         /*
  481          * If the destination address is a multicast address and the outgoing
  482          * interface for the address is specified by the caller, use it.
  483          */
  484         if (IN6_IS_ADDR_MULTICAST(dst) &&
  485             mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) {
  486                 goto done; /* we do not need a route for multicast. */
  487         }
  488 
  489   getroute:
  490         /*
  491          * If the next hop address for the packet is specified by the caller,
  492          * use it as the gateway.
  493          */
  494         if (opts && opts->ip6po_nexthop) {
  495                 struct route_in6 *ron;
  496 
  497                 sin6_next = satosin6(opts->ip6po_nexthop);
  498 
  499                 /* at this moment, we only support AF_INET6 next hops */
  500                 if (sin6_next->sin6_family != AF_INET6) {
  501                         error = EAFNOSUPPORT; /* or should we proceed? */
  502                         goto done;
  503                 }
  504 
  505                 /*
  506                  * If the next hop is an IPv6 address, then the node identified
  507                  * by that address must be a neighbor of the sending host.
  508                  */
  509                 ron = &opts->ip6po_nextroute;
  510                 if ((ron->ro_rt &&
  511                      (ron->ro_rt->rt_flags & (RTF_UP | RTF_LLINFO)) !=
  512                      (RTF_UP | RTF_LLINFO)) ||
  513                     !IN6_ARE_ADDR_EQUAL(&satosin6(&ron->ro_dst)->sin6_addr,
  514                     &sin6_next->sin6_addr)) {
  515                         if (ron->ro_rt) {
  516                                 RTFREE(ron->ro_rt);
  517                                 ron->ro_rt = NULL;
  518                         }
  519                         *satosin6(&ron->ro_dst) = *sin6_next;
  520                 }
  521                 if (ron->ro_rt == NULL) {
  522                         rtalloc((struct route *)ron); /* multi path case? */
  523                         if (ron->ro_rt == NULL ||
  524                             !(ron->ro_rt->rt_flags & RTF_LLINFO)) {
  525                                 if (ron->ro_rt) {
  526                                         RTFREE(ron->ro_rt);
  527                                         ron->ro_rt = NULL;
  528                                 }
  529                                 error = EHOSTUNREACH;
  530                                 goto done;
  531                         }
  532                 }
  533                 rt = ron->ro_rt;
  534                 ifp = rt->rt_ifp;
  535 
  536                 /*
  537                  * When cloning is required, try to allocate a route to the
  538                  * destination so that the caller can store path MTU
  539                  * information.
  540                  */
  541                 if (!clone)
  542                         goto done;
  543         }
  544 
  545         /*
  546          * Use a cached route if it exists and is valid, else try to allocate
  547          * a new one.  Note that we should check the address family of the
  548          * cached destination, in case of sharing the cache with IPv4.
  549          */
  550         if (ro) {
  551                 if (ro->ro_rt &&
  552                     (!(ro->ro_rt->rt_flags & RTF_UP) ||
  553                      ((struct sockaddr *)(&ro->ro_dst))->sa_family != AF_INET6 ||
  554                      !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr,
  555                      dst))) {
  556                         RTFREE(ro->ro_rt);
  557                         ro->ro_rt = (struct rtentry *)NULL;
  558                 }
  559                 if (ro->ro_rt == (struct rtentry *)NULL) {
  560                         struct sockaddr_in6 *sa6;
  561 
  562                         /* No route yet, so try to acquire one */
  563                         bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
  564                         sa6 = (struct sockaddr_in6 *)&ro->ro_dst;
  565                         *sa6 = *dstsock;
  566                         sa6->sin6_scope_id = 0;
  567 
  568                         if (clone) {
  569                                 rtalloc((struct route *)ro);
  570                         } else {
  571                                 ro->ro_rt = rtalloc1(&((struct route *)ro)
  572                                                      ->ro_dst, 0, 0UL);
  573                                 if (ro->ro_rt)
  574                                         RT_UNLOCK(ro->ro_rt);
  575                         }
  576                 }
  577 
  578                 /*
  579                  * do not care about the result if we have the nexthop
  580                  * explicitly specified.
  581                  */
  582                 if (opts && opts->ip6po_nexthop)
  583                         goto done;
  584 
  585                 if (ro->ro_rt) {
  586                         ifp = ro->ro_rt->rt_ifp;
  587 
  588                         if (ifp == NULL) { /* can this really happen? */
  589                                 RTFREE(ro->ro_rt);
  590                                 ro->ro_rt = NULL;
  591                         }
  592                 }
  593                 if (ro->ro_rt == NULL)
  594                         error = EHOSTUNREACH;
  595                 rt = ro->ro_rt;
  596 
  597                 /*
  598                  * Check if the outgoing interface conflicts with
  599                  * the interface specified by ipi6_ifindex (if specified).
  600                  * Note that loopback interface is always okay.
  601                  * (this may happen when we are sending a packet to one of
  602                  *  our own addresses.)
  603                  */
  604                 if (ifp && opts && opts->ip6po_pktinfo &&
  605                     opts->ip6po_pktinfo->ipi6_ifindex) {
  606                         if (!(ifp->if_flags & IFF_LOOPBACK) &&
  607                             ifp->if_index !=
  608                             opts->ip6po_pktinfo->ipi6_ifindex) {
  609                                 error = EHOSTUNREACH;
  610                                 goto done;
  611                         }
  612                 }
  613         }
  614 
  615   done:
  616         if (ifp == NULL && rt == NULL) {
  617                 /*
  618                  * This can happen if the caller did not pass a cached route
  619                  * nor any other hints.  We treat this case an error.
  620                  */
  621                 error = EHOSTUNREACH;
  622         }
  623         if (error == EHOSTUNREACH)
  624                 ip6stat.ip6s_noroute++;
  625 
  626         if (retifp != NULL)
  627                 *retifp = ifp;
  628         if (retrt != NULL)
  629                 *retrt = rt;    /* rt may be NULL */
  630 
  631         return (error);
  632 }
  633 
  634 static int
  635 in6_selectif(dstsock, opts, mopts, ro, retifp)
  636         struct sockaddr_in6 *dstsock;
  637         struct ip6_pktopts *opts;
  638         struct ip6_moptions *mopts;
  639         struct route_in6 *ro;
  640         struct ifnet **retifp;
  641 {
  642         int error;
  643         struct route_in6 sro;
  644         struct rtentry *rt = NULL;
  645 
  646         if (ro == NULL) {
  647                 bzero(&sro, sizeof(sro));
  648                 ro = &sro;
  649         }
  650 
  651         if ((error = selectroute(dstsock, opts, mopts, ro, retifp,
  652                                      &rt, 0, 1)) != 0) {
  653                 if (rt && rt == sro.ro_rt)
  654                         RTFREE(rt);
  655                 return (error);
  656         }
  657 
  658         /*
  659          * do not use a rejected or black hole route.
  660          * XXX: this check should be done in the L2 output routine.
  661          * However, if we skipped this check here, we'd see the following
  662          * scenario:
  663          * - install a rejected route for a scoped address prefix
  664          *   (like fe80::/10)
  665          * - send a packet to a destination that matches the scoped prefix,
  666          *   with ambiguity about the scope zone.
  667          * - pick the outgoing interface from the route, and disambiguate the
  668          *   scope zone with the interface.
  669          * - ip6_output() would try to get another route with the "new"
  670          *   destination, which may be valid.
  671          * - we'd see no error on output.
  672          * Although this may not be very harmful, it should still be confusing.
  673          * We thus reject the case here.
  674          */
  675         if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) {
  676                 int flags = (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
  677 
  678                 if (rt && rt == sro.ro_rt)
  679                         RTFREE(rt);
  680                 return (flags);
  681         }
  682 
  683         /*
  684          * Adjust the "outgoing" interface.  If we're going to loop the packet
  685          * back to ourselves, the ifp would be the loopback interface.
  686          * However, we'd rather know the interface associated to the
  687          * destination address (which should probably be one of our own
  688          * addresses.)
  689          */
  690         if (rt && rt->rt_ifa && rt->rt_ifa->ifa_ifp)
  691                 *retifp = rt->rt_ifa->ifa_ifp;
  692 
  693         if (rt && rt == sro.ro_rt)
  694                 RTFREE(rt);
  695         return (0);
  696 }
  697 
  698 int
  699 in6_selectroute(dstsock, opts, mopts, ro, retifp, retrt, clone)
  700         struct sockaddr_in6 *dstsock;
  701         struct ip6_pktopts *opts;
  702         struct ip6_moptions *mopts;
  703         struct route_in6 *ro;
  704         struct ifnet **retifp;
  705         struct rtentry **retrt;
  706         int clone;              /* meaningful only for bsdi and freebsd. */
  707 {
  708         return (selectroute(dstsock, opts, mopts, ro, retifp,
  709             retrt, clone, 0));
  710 }
  711 
  712 /*
  713  * Default hop limit selection. The precedence is as follows:
  714  * 1. Hoplimit value specified via ioctl.
  715  * 2. (If the outgoing interface is detected) the current
  716  *     hop limit of the interface specified by router advertisement.
  717  * 3. The system default hoplimit.
  718  */
  719 int
  720 in6_selecthlim(in6p, ifp)
  721         struct in6pcb *in6p;
  722         struct ifnet *ifp;
  723 {
  724         if (in6p && in6p->in6p_hops >= 0)
  725                 return (in6p->in6p_hops);
  726         else if (ifp)
  727                 return (ND_IFINFO(ifp)->chlim);
  728         else if (in6p && !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
  729                 struct route_in6 ro6;
  730                 struct ifnet *lifp;
  731 
  732                 bzero(&ro6, sizeof(ro6));
  733                 ro6.ro_dst.sin6_family = AF_INET6;
  734                 ro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
  735                 ro6.ro_dst.sin6_addr = in6p->in6p_faddr;
  736                 rtalloc((struct route *)&ro6);
  737                 if (ro6.ro_rt) {
  738                         lifp = ro6.ro_rt->rt_ifp;
  739                         RTFREE(ro6.ro_rt);
  740                         if (lifp)
  741                                 return (ND_IFINFO(lifp)->chlim);
  742                 } else
  743                         return (ip6_defhlim);
  744         }
  745         return (ip6_defhlim);
  746 }
  747 
  748 /*
  749  * XXX: this is borrowed from in6_pcbbind(). If possible, we should
  750  * share this function by all *bsd*...
  751  */
  752 int
  753 in6_pcbsetport(laddr, inp, cred)
  754         struct in6_addr *laddr;
  755         struct inpcb *inp;
  756         struct ucred *cred;
  757 {
  758         struct socket *so = inp->inp_socket;
  759         u_int16_t lport = 0, first, last, *lastport;
  760         int count, error = 0, wild = 0;
  761         struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
  762 
  763         /* XXX: this is redundant when called from in6_pcbbind */
  764         if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0)
  765                 wild = INPLOOKUP_WILDCARD;
  766 
  767         inp->inp_flags |= INP_ANONPORT;
  768 
  769         if (inp->inp_flags & INP_HIGHPORT) {
  770                 first = ipport_hifirstauto;     /* sysctl */
  771                 last  = ipport_hilastauto;
  772                 lastport = &pcbinfo->lasthi;
  773         } else if (inp->inp_flags & INP_LOWPORT) {
  774                 if ((error = suser_cred(cred, 0)))
  775                         return error;
  776                 first = ipport_lowfirstauto;    /* 1023 */
  777                 last  = ipport_lowlastauto;     /* 600 */
  778                 lastport = &pcbinfo->lastlow;
  779         } else {
  780                 first = ipport_firstauto;       /* sysctl */
  781                 last  = ipport_lastauto;
  782                 lastport = &pcbinfo->lastport;
  783         }
  784         /*
  785          * Simple check to ensure all ports are not used up causing
  786          * a deadlock here.
  787          *
  788          * We split the two cases (up and down) so that the direction
  789          * is not being tested on each round of the loop.
  790          */
  791         if (first > last) {
  792                 /*
  793                  * counting down
  794                  */
  795                 count = first - last;
  796 
  797                 do {
  798                         if (count-- < 0) {      /* completely used? */
  799                                 /*
  800                                  * Undo any address bind that may have
  801                                  * occurred above.
  802                                  */
  803                                 inp->in6p_laddr = in6addr_any;
  804                                 return (EAGAIN);
  805                         }
  806                         --*lastport;
  807                         if (*lastport > first || *lastport < last)
  808                                 *lastport = first;
  809                         lport = htons(*lastport);
  810                 } while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
  811                                              lport, wild));
  812         } else {
  813                 /*
  814                          * counting up
  815                          */
  816                 count = last - first;
  817 
  818                 do {
  819                         if (count-- < 0) {      /* completely used? */
  820                                 /*
  821                                  * Undo any address bind that may have
  822                                  * occurred above.
  823                                  */
  824                                 inp->in6p_laddr = in6addr_any;
  825                                 return (EAGAIN);
  826                         }
  827                         ++*lastport;
  828                         if (*lastport < first || *lastport > last)
  829                                 *lastport = first;
  830                         lport = htons(*lastport);
  831                 } while (in6_pcblookup_local(pcbinfo,
  832                                              &inp->in6p_laddr, lport, wild));
  833         }
  834 
  835         inp->inp_lport = lport;
  836         if (in_pcbinshash(inp) != 0) {
  837                 inp->in6p_laddr = in6addr_any;
  838                 inp->inp_lport = 0;
  839                 return (EAGAIN);
  840         }
  841 
  842         return (0);
  843 }
  844 
  845 void
  846 addrsel_policy_init()
  847 {
  848         ADDRSEL_LOCK_INIT();
  849         ADDRSEL_SXLOCK_INIT();
  850 
  851         init_policy_queue();
  852 
  853         /* initialize the "last resort" policy */
  854         bzero(&defaultaddrpolicy, sizeof(defaultaddrpolicy));
  855         defaultaddrpolicy.label = ADDR_LABEL_NOTAPP;
  856 }
  857 
  858 static struct in6_addrpolicy *
  859 lookup_addrsel_policy(key)
  860         struct sockaddr_in6 *key;
  861 {
  862         struct in6_addrpolicy *match = NULL;
  863 
  864         ADDRSEL_LOCK();
  865         match = match_addrsel_policy(key);
  866 
  867         if (match == NULL)
  868                 match = &defaultaddrpolicy;
  869         else
  870                 match->use++;
  871         ADDRSEL_UNLOCK();
  872 
  873         return (match);
  874 }
  875 
  876 /*
  877  * Subroutines to manage the address selection policy table via sysctl.
  878  */
  879 struct walkarg {
  880         struct sysctl_req *w_req;
  881 };
  882 
  883 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS);
  884 SYSCTL_DECL(_net_inet6_ip6);
  885 SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy,
  886         CTLFLAG_RD, in6_src_sysctl, "");
  887 
  888 static int
  889 in6_src_sysctl(SYSCTL_HANDLER_ARGS)
  890 {
  891         struct walkarg w;
  892 
  893         if (req->newptr)
  894                 return EPERM;
  895 
  896         bzero(&w, sizeof(w));
  897         w.w_req = req;
  898 
  899         return (walk_addrsel_policy(dump_addrsel_policyent, &w));
  900 }
  901 
  902 int
  903 in6_src_ioctl(cmd, data)
  904         u_long cmd;
  905         caddr_t data;
  906 {
  907         int i;
  908         struct in6_addrpolicy ent0;
  909 
  910         if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY)
  911                 return (EOPNOTSUPP); /* check for safety */
  912 
  913         ent0 = *(struct in6_addrpolicy *)data;
  914 
  915         if (ent0.label == ADDR_LABEL_NOTAPP)
  916                 return (EINVAL);
  917         /* check if the prefix mask is consecutive. */
  918         if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0)
  919                 return (EINVAL);
  920         /* clear trailing garbages (if any) of the prefix address. */
  921         for (i = 0; i < 4; i++) {
  922                 ent0.addr.sin6_addr.s6_addr32[i] &=
  923                         ent0.addrmask.sin6_addr.s6_addr32[i];
  924         }
  925         ent0.use = 0;
  926 
  927         switch (cmd) {
  928         case SIOCAADDRCTL_POLICY:
  929                 return (add_addrsel_policyent(&ent0));
  930         case SIOCDADDRCTL_POLICY:
  931                 return (delete_addrsel_policyent(&ent0));
  932         }
  933 
  934         return (0);             /* XXX: compromise compilers */
  935 }
  936 
  937 /*
  938  * The followings are implementation of the policy table using a
  939  * simple tail queue.
  940  * XXX such details should be hidden.
  941  * XXX implementation using binary tree should be more efficient.
  942  */
  943 struct addrsel_policyent {
  944         TAILQ_ENTRY(addrsel_policyent) ape_entry;
  945         struct in6_addrpolicy ape_policy;
  946 };
  947 
  948 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent);
  949 
  950 struct addrsel_policyhead addrsel_policytab;
  951 
  952 static void
  953 init_policy_queue()
  954 {
  955         TAILQ_INIT(&addrsel_policytab);
  956 }
  957 
  958 static int
  959 add_addrsel_policyent(newpolicy)
  960         struct in6_addrpolicy *newpolicy;
  961 {
  962         struct addrsel_policyent *new, *pol;
  963 
  964         MALLOC(new, struct addrsel_policyent *, sizeof(*new), M_IFADDR,
  965                M_WAITOK);
  966         ADDRSEL_XLOCK();
  967         ADDRSEL_LOCK();
  968 
  969         /* duplication check */
  970         TAILQ_FOREACH(pol, &addrsel_policytab, ape_entry) {
  971                 if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr,
  972                                        &pol->ape_policy.addr.sin6_addr) &&
  973                     IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr,
  974                                        &pol->ape_policy.addrmask.sin6_addr)) {
  975                         ADDRSEL_UNLOCK();
  976                         ADDRSEL_XUNLOCK();
  977                         FREE(new, M_IFADDR);
  978                         return (EEXIST);        /* or override it? */
  979                 }
  980         }
  981 
  982         bzero(new, sizeof(*new));
  983 
  984         /* XXX: should validate entry */
  985         new->ape_policy = *newpolicy;
  986 
  987         TAILQ_INSERT_TAIL(&addrsel_policytab, new, ape_entry);
  988         ADDRSEL_UNLOCK();
  989         ADDRSEL_XUNLOCK();
  990 
  991         return (0);
  992 }
  993 
  994 static int
  995 delete_addrsel_policyent(key)
  996         struct in6_addrpolicy *key;
  997 {
  998         struct addrsel_policyent *pol;
  999 
 1000         ADDRSEL_XLOCK();
 1001         ADDRSEL_LOCK();
 1002 
 1003         /* search for the entry in the table */
 1004         TAILQ_FOREACH(pol, &addrsel_policytab, ape_entry) {
 1005                 if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr,
 1006                     &pol->ape_policy.addr.sin6_addr) &&
 1007                     IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr,
 1008                     &pol->ape_policy.addrmask.sin6_addr)) {
 1009                         break;
 1010                 }
 1011         }
 1012         if (pol == NULL) {
 1013                 ADDRSEL_UNLOCK();
 1014                 ADDRSEL_XUNLOCK();
 1015                 return (ESRCH);
 1016         }
 1017 
 1018         TAILQ_REMOVE(&addrsel_policytab, pol, ape_entry);
 1019         ADDRSEL_UNLOCK();
 1020         ADDRSEL_XUNLOCK();
 1021 
 1022         return (0);
 1023 }
 1024 
 1025 static int
 1026 walk_addrsel_policy(callback, w)
 1027         int (*callback) __P((struct in6_addrpolicy *, void *));
 1028         void *w;
 1029 {
 1030         struct addrsel_policyent *pol;
 1031         int error = 0;
 1032 
 1033         ADDRSEL_SLOCK();
 1034         TAILQ_FOREACH(pol, &addrsel_policytab, ape_entry) {
 1035                 if ((error = (*callback)(&pol->ape_policy, w)) != 0) {
 1036                         ADDRSEL_SUNLOCK();
 1037                         return (error);
 1038                 }
 1039         }
 1040         ADDRSEL_SUNLOCK();
 1041         return (error);
 1042 }
 1043 
 1044 static int
 1045 dump_addrsel_policyent(pol, arg)
 1046         struct in6_addrpolicy *pol;
 1047         void *arg;
 1048 {
 1049         int error = 0;
 1050         struct walkarg *w = arg;
 1051 
 1052         error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol));
 1053 
 1054         return (error);
 1055 }
 1056 
 1057 static struct in6_addrpolicy *
 1058 match_addrsel_policy(key)
 1059         struct sockaddr_in6 *key;
 1060 {
 1061         struct addrsel_policyent *pent;
 1062         struct in6_addrpolicy *bestpol = NULL, *pol;
 1063         int matchlen, bestmatchlen = -1;
 1064         u_char *mp, *ep, *k, *p, m;
 1065 
 1066         TAILQ_FOREACH(pent, &addrsel_policytab, ape_entry) {
 1067                 matchlen = 0;
 1068 
 1069                 pol = &pent->ape_policy;
 1070                 mp = (u_char *)&pol->addrmask.sin6_addr;
 1071                 ep = mp + 16;   /* XXX: scope field? */
 1072                 k = (u_char *)&key->sin6_addr;
 1073                 p = (u_char *)&pol->addr.sin6_addr;
 1074                 for (; mp < ep && *mp; mp++, k++, p++) {
 1075                         m = *mp;
 1076                         if ((*k & m) != *p)
 1077                                 goto next; /* not match */
 1078                         if (m == 0xff) /* short cut for a typical case */
 1079                                 matchlen += 8;
 1080                         else {
 1081                                 while (m >= 0x80) {
 1082                                         matchlen++;
 1083                                         m <<= 1;
 1084                                 }
 1085                         }
 1086                 }
 1087 
 1088                 /* matched.  check if this is better than the current best. */
 1089                 if (bestpol == NULL ||
 1090                     matchlen > bestmatchlen) {
 1091                         bestpol = pol;
 1092                         bestmatchlen = matchlen;
 1093                 }
 1094 
 1095           next:
 1096                 continue;
 1097         }
 1098 
 1099         return (bestpol);
 1100 }

Cache object: 5f0f759cf6142e4ff20e0cec5a4f8309


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