The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netinet6/mld6.c

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    1 /*      $NetBSD: mld6.c,v 1.47 2008/08/22 17:11:39 adrianp Exp $        */
    2 /*      $KAME: mld6.c,v 1.25 2001/01/16 14:14:18 itojun Exp $   */
    3 
    4 /*
    5  * Copyright (C) 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) 1992, 1993
   35  *      The Regents of the University of California.  All rights reserved.
   36  *
   37  * This code is derived from software contributed to Berkeley by
   38  * Stephen Deering of Stanford University.
   39  *
   40  * Redistribution and use in source and binary forms, with or without
   41  * modification, are permitted provided that the following conditions
   42  * are met:
   43  * 1. Redistributions of source code must retain the above copyright
   44  *    notice, this list of conditions and the following disclaimer.
   45  * 2. Redistributions in binary form must reproduce the above copyright
   46  *    notice, this list of conditions and the following disclaimer in the
   47  *    documentation and/or other materials provided with the distribution.
   48  * 3. Neither the name of the University nor the names of its contributors
   49  *    may be used to endorse or promote products derived from this software
   50  *    without specific prior written permission.
   51  *
   52  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   62  * SUCH DAMAGE.
   63  *
   64  *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
   65  */
   66 
   67 /*
   68  * Copyright (c) 1988 Stephen Deering.
   69  *
   70  * This code is derived from software contributed to Berkeley by
   71  * Stephen Deering of Stanford University.
   72  *
   73  * Redistribution and use in source and binary forms, with or without
   74  * modification, are permitted provided that the following conditions
   75  * are met:
   76  * 1. Redistributions of source code must retain the above copyright
   77  *    notice, this list of conditions and the following disclaimer.
   78  * 2. Redistributions in binary form must reproduce the above copyright
   79  *    notice, this list of conditions and the following disclaimer in the
   80  *    documentation and/or other materials provided with the distribution.
   81  * 3. All advertising materials mentioning features or use of this software
   82  *    must display the following acknowledgement:
   83  *      This product includes software developed by the University of
   84  *      California, Berkeley and its contributors.
   85  * 4. Neither the name of the University nor the names of its contributors
   86  *    may be used to endorse or promote products derived from this software
   87  *    without specific prior written permission.
   88  *
   89  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   90  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   91  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   92  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   93  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   94  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   95  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   96  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   97  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   98  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   99  * SUCH DAMAGE.
  100  *
  101  *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
  102  */
  103 
  104 #include <sys/cdefs.h>
  105 __KERNEL_RCSID(0, "$NetBSD: mld6.c,v 1.47 2008/08/22 17:11:39 adrianp Exp $");
  106 
  107 #include "opt_inet.h"
  108 
  109 #include <sys/param.h>
  110 #include <sys/systm.h>
  111 #include <sys/mbuf.h>
  112 #include <sys/socket.h>
  113 #include <sys/socketvar.h>
  114 #include <sys/protosw.h>
  115 #include <sys/syslog.h>
  116 #include <sys/sysctl.h>
  117 #include <sys/kernel.h>
  118 #include <sys/callout.h>
  119 
  120 #include <net/if.h>
  121 
  122 #include <netinet/in.h>
  123 #include <netinet/in_var.h>
  124 #include <netinet6/in6_var.h>
  125 #include <netinet/ip6.h>
  126 #include <netinet6/ip6_var.h>
  127 #include <netinet6/scope6_var.h>
  128 #include <netinet/icmp6.h>
  129 #include <netinet6/icmp6_private.h>
  130 #include <netinet6/mld6_var.h>
  131 
  132 #include <net/net_osdep.h>
  133 
  134 
  135 /*
  136  * This structure is used to keep track of in6_multi chains which belong to
  137  * deleted interface addresses.
  138  */
  139 static LIST_HEAD(, multi6_kludge) in6_mk; /* XXX BSS initialization */
  140 
  141 struct multi6_kludge {
  142         LIST_ENTRY(multi6_kludge) mk_entry;
  143         struct ifnet *mk_ifp;
  144         struct in6_multihead mk_head;
  145 };
  146 
  147 
  148 /*
  149  * Protocol constants
  150  */
  151 
  152 /*
  153  * time between repetitions of a node's initial report of interest in a
  154  * multicast address(in seconds)
  155  */
  156 #define MLD_UNSOLICITED_REPORT_INTERVAL 10
  157 
  158 static struct ip6_pktopts ip6_opts;
  159 
  160 static void mld_start_listening(struct in6_multi *);
  161 static void mld_stop_listening(struct in6_multi *);
  162 
  163 static struct mld_hdr * mld_allocbuf(struct mbuf **, int, struct in6_multi *,
  164         int);
  165 static void mld_sendpkt(struct in6_multi *, int, const struct in6_addr *);
  166 static void mld_starttimer(struct in6_multi *);
  167 static void mld_stoptimer(struct in6_multi *);
  168 static u_long mld_timerresid(struct in6_multi *);
  169 
  170 void
  171 mld_init(void)
  172 {
  173         static u_int8_t hbh_buf[8];
  174         struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
  175         u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
  176 
  177         /* ip6h_nxt will be fill in later */
  178         hbh->ip6h_len = 0;      /* (8 >> 3) - 1 */
  179 
  180         /* XXX: grotty hard coding... */
  181         hbh_buf[2] = IP6OPT_PADN;       /* 2 byte padding */
  182         hbh_buf[3] = 0;
  183         hbh_buf[4] = IP6OPT_RTALERT;
  184         hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
  185         bcopy((void *)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));
  186 
  187         ip6_opts.ip6po_hbh = hbh;
  188         /* We will specify the hoplimit by a multicast option. */
  189         ip6_opts.ip6po_hlim = -1;
  190 }
  191 
  192 static void
  193 mld_starttimer(struct in6_multi *in6m)
  194 {
  195         struct timeval now;
  196 
  197         microtime(&now);
  198         in6m->in6m_timer_expire.tv_sec = now.tv_sec + in6m->in6m_timer / hz;
  199         in6m->in6m_timer_expire.tv_usec = now.tv_usec +
  200             (in6m->in6m_timer % hz) * (1000000 / hz);
  201         if (in6m->in6m_timer_expire.tv_usec > 1000000) {
  202                 in6m->in6m_timer_expire.tv_sec++;
  203                 in6m->in6m_timer_expire.tv_usec -= 1000000;
  204         }
  205 
  206         /* start or restart the timer */
  207         callout_schedule(&in6m->in6m_timer_ch, in6m->in6m_timer);
  208 }
  209 
  210 static void
  211 mld_stoptimer(struct in6_multi *in6m)
  212 {
  213         if (in6m->in6m_timer == IN6M_TIMER_UNDEF)
  214                 return;
  215 
  216         callout_stop(&in6m->in6m_timer_ch);
  217 
  218         in6m->in6m_timer = IN6M_TIMER_UNDEF;
  219 }
  220 
  221 static void
  222 mld_timeo(void *arg)
  223 {
  224         struct in6_multi *in6m = arg;
  225 
  226         mutex_enter(softnet_lock);
  227         KERNEL_LOCK(1, NULL);
  228 
  229         in6m->in6m_timer = IN6M_TIMER_UNDEF;
  230 
  231         switch (in6m->in6m_state) {
  232         case MLD_REPORTPENDING:
  233                 mld_start_listening(in6m);
  234                 break;
  235         default:
  236                 mld_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
  237                 break;
  238         }
  239 
  240         KERNEL_UNLOCK_ONE(NULL);
  241         mutex_exit(softnet_lock);
  242 }
  243 
  244 static u_long
  245 mld_timerresid(struct in6_multi *in6m)
  246 {
  247         struct timeval now, diff;
  248 
  249         microtime(&now);
  250 
  251         if (now.tv_sec > in6m->in6m_timer_expire.tv_sec ||
  252             (now.tv_sec == in6m->in6m_timer_expire.tv_sec &&
  253             now.tv_usec > in6m->in6m_timer_expire.tv_usec)) {
  254                 return (0);
  255         }
  256         diff = in6m->in6m_timer_expire;
  257         diff.tv_sec -= now.tv_sec;
  258         diff.tv_usec -= now.tv_usec;
  259         if (diff.tv_usec < 0) {
  260                 diff.tv_sec--;
  261                 diff.tv_usec += 1000000;
  262         }
  263 
  264         /* return the remaining time in milliseconds */
  265         return diff.tv_sec * 1000 + diff.tv_usec / 1000;
  266 }
  267 
  268 static void
  269 mld_start_listening(struct in6_multi *in6m)
  270 {
  271         struct in6_addr all_in6;
  272 
  273         /*
  274          * RFC2710 page 10:
  275          * The node never sends a Report or Done for the link-scope all-nodes
  276          * address.
  277          * MLD messages are never sent for multicast addresses whose scope is 0
  278          * (reserved) or 1 (node-local).
  279          */
  280         all_in6 = in6addr_linklocal_allnodes;
  281         if (in6_setscope(&all_in6, in6m->in6m_ifp, NULL)) {
  282                 /* XXX: this should not happen! */
  283                 in6m->in6m_timer = 0;
  284                 in6m->in6m_state = MLD_OTHERLISTENER;
  285         }
  286         if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
  287             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) < IPV6_ADDR_SCOPE_LINKLOCAL) {
  288                 in6m->in6m_timer = IN6M_TIMER_UNDEF;
  289                 in6m->in6m_state = MLD_OTHERLISTENER;
  290         } else {
  291                 mld_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
  292                 in6m->in6m_timer = arc4random() %
  293                     (MLD_UNSOLICITED_REPORT_INTERVAL * hz);
  294                 in6m->in6m_state = MLD_IREPORTEDLAST;
  295 
  296                 mld_starttimer(in6m);
  297         }
  298 }
  299 
  300 static void
  301 mld_stop_listening(struct in6_multi *in6m)
  302 {
  303         struct in6_addr allnode, allrouter;
  304 
  305         allnode = in6addr_linklocal_allnodes;
  306         if (in6_setscope(&allnode, in6m->in6m_ifp, NULL)) {
  307                 /* XXX: this should not happen! */
  308                 return;
  309         }
  310         allrouter = in6addr_linklocal_allrouters;
  311         if (in6_setscope(&allrouter, in6m->in6m_ifp, NULL)) {
  312                 /* XXX impossible */
  313                 return;
  314         }
  315 
  316         if (in6m->in6m_state == MLD_IREPORTEDLAST &&
  317             (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &allnode)) &&
  318             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) >
  319             IPV6_ADDR_SCOPE_INTFACELOCAL) {
  320                 mld_sendpkt(in6m, MLD_LISTENER_DONE, &allrouter);
  321         }
  322 }
  323 
  324 void
  325 mld_input(struct mbuf *m, int off)
  326 {
  327         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  328         struct mld_hdr *mldh;
  329         struct ifnet *ifp = m->m_pkthdr.rcvif;
  330         struct in6_multi *in6m = NULL;
  331         struct in6_addr mld_addr, all_in6;
  332         struct in6_ifaddr *ia;
  333         u_long timer = 0;       /* timer value in the MLD query header */
  334 
  335         IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
  336         if (mldh == NULL) {
  337                 ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
  338                 return;
  339         }
  340 
  341         /* source address validation */
  342         ip6 = mtod(m, struct ip6_hdr *);/* in case mpullup */
  343         if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
  344                 /*
  345                  * RFC3590 allows the IPv6 unspecified address as the source
  346                  * address of MLD report and done messages.  However, as this
  347                  * same document says, this special rule is for snooping
  348                  * switches and the RFC requires routers to discard MLD packets
  349                  * with the unspecified source address.  The RFC only talks
  350                  * about hosts receiving an MLD query or report in Security
  351                  * Considerations, but this is probably the correct intention.
  352                  * RFC3590 does not talk about other cases than link-local and
  353                  * the unspecified source addresses, but we believe the same
  354                  * rule should be applied.
  355                  * As a result, we only allow link-local addresses as the
  356                  * source address; otherwise, simply discard the packet.
  357                  */
  358 #if 0
  359                 /*
  360                  * XXX: do not log in an input path to avoid log flooding,
  361                  * though RFC3590 says "SHOULD log" if the source of a query
  362                  * is the unspecified address.
  363                  */
  364                 log(LOG_INFO,
  365                     "mld_input: src %s is not link-local (grp=%s)\n",
  366                     ip6_sprintf(&ip6->ip6_src), ip6_sprintf(&mldh->mld_addr));
  367 #endif
  368                 m_freem(m);
  369                 return;
  370         }
  371 
  372         /*
  373          * make a copy for local work (in6_setscope() may modify the 1st arg)
  374          */
  375         mld_addr = mldh->mld_addr;
  376         if (in6_setscope(&mld_addr, ifp, NULL)) {
  377                 /* XXX: this should not happen! */
  378                 m_free(m);
  379                 return;
  380         }
  381 
  382         /*
  383          * In the MLD specification, there are 3 states and a flag.
  384          *
  385          * In Non-Listener state, we simply don't have a membership record.
  386          * In Delaying Listener state, our timer is running (in6m->in6m_timer)
  387          * In Idle Listener state, our timer is not running 
  388          * (in6m->in6m_timer==IN6M_TIMER_UNDEF)
  389          *
  390          * The flag is in6m->in6m_state, it is set to MLD_OTHERLISTENER if
  391          * we have heard a report from another member, or MLD_IREPORTEDLAST
  392          * if we sent the last report.
  393          */
  394         switch (mldh->mld_type) {
  395         case MLD_LISTENER_QUERY:
  396                 if (ifp->if_flags & IFF_LOOPBACK)
  397                         break;
  398 
  399                 if (!IN6_IS_ADDR_UNSPECIFIED(&mld_addr) &&
  400                     !IN6_IS_ADDR_MULTICAST(&mld_addr))
  401                         break;  /* print error or log stat? */
  402 
  403                 all_in6 = in6addr_linklocal_allnodes;
  404                 if (in6_setscope(&all_in6, ifp, NULL)) {
  405                         /* XXX: this should not happen! */
  406                         break;
  407                 }
  408 
  409                 /*
  410                  * - Start the timers in all of our membership records
  411                  *   that the query applies to for the interface on
  412                  *   which the query arrived excl. those that belong
  413                  *   to the "all-nodes" group (ff02::1).
  414                  * - Restart any timer that is already running but has
  415                  *   a value longer than the requested timeout.
  416                  * - Use the value specified in the query message as
  417                  *   the maximum timeout.
  418                  */
  419                 timer = ntohs(mldh->mld_maxdelay);
  420 
  421                 IFP_TO_IA6(ifp, ia);
  422                 if (ia == NULL)
  423                         break;
  424 
  425                 LIST_FOREACH(in6m, &ia->ia6_multiaddrs, in6m_entry) {
  426                         if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
  427                             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
  428                             IPV6_ADDR_SCOPE_LINKLOCAL)
  429                                 continue;
  430 
  431                         if (in6m->in6m_state == MLD_REPORTPENDING)
  432                                 continue; /* we are not yet ready */
  433 
  434                         if (!IN6_IS_ADDR_UNSPECIFIED(&mld_addr) &&
  435                             !IN6_ARE_ADDR_EQUAL(&mld_addr, &in6m->in6m_addr))
  436                                 continue;
  437 
  438                         if (timer == 0) {
  439                                 /* send a report immediately */
  440                                 mld_stoptimer(in6m);
  441                                 mld_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
  442                                 in6m->in6m_state = MLD_IREPORTEDLAST;
  443                         } else if (in6m->in6m_timer == IN6M_TIMER_UNDEF ||
  444                             mld_timerresid(in6m) > timer) {
  445                                 in6m->in6m_timer =
  446                                    1 + (arc4random() % timer) * hz / 1000;
  447                                 mld_starttimer(in6m);
  448                         }
  449                 }
  450                 break;
  451 
  452         case MLD_LISTENER_REPORT:
  453                 /*
  454                  * For fast leave to work, we have to know that we are the
  455                  * last person to send a report for this group.  Reports
  456                  * can potentially get looped back if we are a multicast
  457                  * router, so discard reports sourced by me.
  458                  * Note that it is impossible to check IFF_LOOPBACK flag of
  459                  * ifp for this purpose, since ip6_mloopback pass the physical
  460                  * interface to looutput.
  461                  */
  462                 if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
  463                         break;
  464 
  465                 if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
  466                         break;
  467 
  468                 /*
  469                  * If we belong to the group being reported, stop
  470                  * our timer for that group.
  471                  */
  472                 IN6_LOOKUP_MULTI(mld_addr, ifp, in6m);
  473                 if (in6m) {
  474                         mld_stoptimer(in6m); /* transit to idle state */
  475                         in6m->in6m_state = MLD_OTHERLISTENER; /* clear flag */
  476                 }
  477                 break;
  478         default:                /* this is impossible */
  479 #if 0
  480                 /*
  481                  * this case should be impossible because of filtering in
  482                  * icmp6_input().  But we explicitly disabled this part
  483                  * just in case.
  484                  */
  485                 log(LOG_ERR, "mld_input: illegal type(%d)", mldh->mld_type);
  486 #endif
  487                 break;
  488         }
  489 
  490         m_freem(m);
  491 }
  492 
  493 static void
  494 mld_sendpkt(struct in6_multi *in6m, int type, 
  495         const struct in6_addr *dst)
  496 {
  497         struct mbuf *mh;
  498         struct mld_hdr *mldh;
  499         struct ip6_hdr *ip6 = NULL;
  500         struct ip6_moptions im6o;
  501         struct in6_ifaddr *ia = NULL;
  502         struct ifnet *ifp = in6m->in6m_ifp;
  503         int ignflags;
  504 
  505         /*
  506          * At first, find a link local address on the outgoing interface
  507          * to use as the source address of the MLD packet.
  508          * We do not reject tentative addresses for MLD report to deal with
  509          * the case where we first join a link-local address.
  510          */
  511         ignflags = (IN6_IFF_NOTREADY|IN6_IFF_ANYCAST) & ~IN6_IFF_TENTATIVE;
  512         if ((ia = in6ifa_ifpforlinklocal(ifp, ignflags)) == NULL)
  513                 return;
  514         if ((ia->ia6_flags & IN6_IFF_TENTATIVE))
  515                 ia = NULL;
  516 
  517         /* Allocate two mbufs to store IPv6 header and MLD header */
  518         mldh = mld_allocbuf(&mh, sizeof(struct mld_hdr), in6m, type);
  519         if (mldh == NULL)
  520                 return;
  521 
  522         /* fill src/dst here */
  523         ip6 = mtod(mh, struct ip6_hdr *);
  524         ip6->ip6_src = ia ? ia->ia_addr.sin6_addr : in6addr_any;
  525         ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
  526 
  527         mldh->mld_addr = in6m->in6m_addr;
  528         in6_clearscope(&mldh->mld_addr); /* XXX */
  529         mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
  530             sizeof(struct mld_hdr));
  531 
  532         /* construct multicast option */
  533         memset(&im6o, 0, sizeof(im6o));
  534         im6o.im6o_multicast_ifp = ifp;
  535         im6o.im6o_multicast_hlim = 1;
  536 
  537         /*
  538          * Request loopback of the report if we are acting as a multicast
  539          * router, so that the process-level routing daemon can hear it.
  540          */
  541         im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
  542 
  543         /* increment output statictics */
  544         ICMP6_STATINC(ICMP6_STAT_OUTHIST + type);
  545         icmp6_ifstat_inc(ifp, ifs6_out_msg);
  546         switch (type) {
  547         case MLD_LISTENER_QUERY:
  548                 icmp6_ifstat_inc(ifp, ifs6_out_mldquery);
  549                 break;
  550         case MLD_LISTENER_REPORT:
  551                 icmp6_ifstat_inc(ifp, ifs6_out_mldreport);
  552                 break;
  553         case MLD_LISTENER_DONE:
  554                 icmp6_ifstat_inc(ifp, ifs6_out_mlddone);
  555                 break;
  556         }
  557 
  558         ip6_output(mh, &ip6_opts, NULL, ia ? 0 : IPV6_UNSPECSRC,
  559             &im6o, (struct socket *)NULL, NULL);
  560 }
  561 
  562 static struct mld_hdr *
  563 mld_allocbuf(struct mbuf **mh, int len, struct in6_multi *in6m,
  564     int type)
  565 {
  566         struct mbuf *md;
  567         struct mld_hdr *mldh;
  568         struct ip6_hdr *ip6;
  569 
  570         /*
  571          * Allocate mbufs to store ip6 header and MLD header.
  572          * We allocate 2 mbufs and make chain in advance because
  573          * it is more convenient when inserting the hop-by-hop option later.
  574          */
  575         MGETHDR(*mh, M_DONTWAIT, MT_HEADER);
  576         if (*mh == NULL)
  577                 return NULL;
  578         MGET(md, M_DONTWAIT, MT_DATA);
  579         if (md == NULL) {
  580                 m_free(*mh);
  581                 *mh = NULL;
  582                 return NULL;
  583         }
  584         (*mh)->m_next = md;
  585         md->m_next = NULL;
  586 
  587         (*mh)->m_pkthdr.rcvif = NULL;
  588         (*mh)->m_pkthdr.len = sizeof(struct ip6_hdr) + len;
  589         (*mh)->m_len = sizeof(struct ip6_hdr);
  590         MH_ALIGN(*mh, sizeof(struct ip6_hdr));
  591 
  592         /* fill in the ip6 header */
  593         ip6 = mtod(*mh, struct ip6_hdr *);
  594         memset(ip6, 0, sizeof(*ip6));
  595         ip6->ip6_flow = 0;
  596         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
  597         ip6->ip6_vfc |= IPV6_VERSION;
  598         /* ip6_plen will be set later */
  599         ip6->ip6_nxt = IPPROTO_ICMPV6;
  600         /* ip6_hlim will be set by im6o.im6o_multicast_hlim */
  601         /* ip6_src/dst will be set by mld_sendpkt() or mld_sendbuf() */
  602 
  603         /* fill in the MLD header as much as possible */
  604         md->m_len = len;
  605         mldh = mtod(md, struct mld_hdr *);
  606         memset(mldh, 0, len);
  607         mldh->mld_type = type;
  608         return mldh;
  609 }
  610 
  611 /*
  612  * Add an address to the list of IP6 multicast addresses for a given interface.
  613  */
  614 struct  in6_multi *
  615 in6_addmulti(struct in6_addr *maddr6, struct ifnet *ifp, 
  616         int *errorp, int timer)
  617 {
  618         struct  in6_ifaddr *ia;
  619         struct  in6_ifreq ifr;
  620         struct  in6_multi *in6m;
  621         int     s = splsoftnet();
  622 
  623         *errorp = 0;
  624 
  625         /*
  626          * See if address already in list.
  627          */
  628         IN6_LOOKUP_MULTI(*maddr6, ifp, in6m);
  629         if (in6m != NULL) {
  630                 /*
  631                  * Found it; just increment the refrence count.
  632                  */
  633                 in6m->in6m_refcount++;
  634         } else {
  635                 /*
  636                  * New address; allocate a new multicast record
  637                  * and link it into the interface's multicast list.
  638                  */
  639                 in6m = (struct in6_multi *)
  640                         malloc(sizeof(*in6m), M_IPMADDR, M_NOWAIT);
  641                 if (in6m == NULL) {
  642                         splx(s);
  643                         *errorp = ENOBUFS;
  644                         return (NULL);
  645                 }
  646 
  647                 memset(in6m, 0, sizeof(*in6m));
  648                 in6m->in6m_addr = *maddr6;
  649                 in6m->in6m_ifp = ifp;
  650                 in6m->in6m_refcount = 1;
  651                 in6m->in6m_timer = IN6M_TIMER_UNDEF;
  652                 IFP_TO_IA6(ifp, ia);
  653                 if (ia == NULL) {
  654                         free(in6m, M_IPMADDR);
  655                         splx(s);
  656                         *errorp = EADDRNOTAVAIL; /* appropriate? */
  657                         return (NULL);
  658                 }
  659                 in6m->in6m_ia = ia;
  660                 IFAREF(&ia->ia_ifa); /* gain a reference */
  661                 LIST_INSERT_HEAD(&ia->ia6_multiaddrs, in6m, in6m_entry);
  662 
  663                 /*
  664                  * Ask the network driver to update its multicast reception
  665                  * filter appropriately for the new address.
  666                  */
  667                 sockaddr_in6_init(&ifr.ifr_addr, maddr6, 0, 0, 0);
  668                 if (ifp->if_ioctl == NULL)
  669                         *errorp = ENXIO; /* XXX: appropriate? */
  670                 else
  671                         *errorp = (*ifp->if_ioctl)(ifp, SIOCADDMULTI, &ifr);
  672                 if (*errorp) {
  673                         LIST_REMOVE(in6m, in6m_entry);
  674                         free(in6m, M_IPMADDR);
  675                         IFAFREE(&ia->ia_ifa);
  676                         splx(s);
  677                         return (NULL);
  678                 }
  679 
  680                 callout_init(&in6m->in6m_timer_ch, CALLOUT_MPSAFE);
  681                 callout_setfunc(&in6m->in6m_timer_ch, mld_timeo, in6m);
  682                 in6m->in6m_timer = timer;
  683                 if (in6m->in6m_timer > 0) {
  684                         in6m->in6m_state = MLD_REPORTPENDING;
  685                         mld_starttimer(in6m);
  686 
  687                         splx(s);
  688                         return (in6m);
  689                 }
  690 
  691                 /*
  692                  * Let MLD6 know that we have joined a new IP6 multicast
  693                  * group.
  694                  */
  695                 mld_start_listening(in6m);
  696         }
  697         splx(s);
  698         return (in6m);
  699 }
  700 
  701 /*
  702  * Delete a multicast address record.
  703  */
  704 void
  705 in6_delmulti(struct in6_multi *in6m)
  706 {
  707         struct  in6_ifreq ifr;
  708         struct  in6_ifaddr *ia;
  709         int     s = splsoftnet();
  710 
  711         mld_stoptimer(in6m);
  712 
  713         if (--in6m->in6m_refcount == 0) {
  714                 /*
  715                  * No remaining claims to this record; let MLD6 know
  716                  * that we are leaving the multicast group.
  717                  */
  718                 mld_stop_listening(in6m);
  719 
  720                 /*
  721                  * Unlink from list.
  722                  */
  723                 LIST_REMOVE(in6m, in6m_entry);
  724                 if (in6m->in6m_ia != NULL) {
  725                         IFAFREE(&in6m->in6m_ia->ia_ifa); /* release reference */
  726                         in6m->in6m_ia = NULL;
  727                 }
  728 
  729                 /*
  730                  * Delete all references of this multicasting group from
  731                  * the membership arrays
  732                  */
  733                 for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
  734                         struct in6_multi_mship *imm;
  735                         LIST_FOREACH(imm, &ia->ia6_memberships, i6mm_chain) {
  736                                 if (imm->i6mm_maddr == in6m)
  737                                         imm->i6mm_maddr = NULL;
  738                         }
  739                 }
  740 
  741                 /*
  742                  * Notify the network driver to update its multicast
  743                  * reception filter.
  744                  */
  745                 sockaddr_in6_init(&ifr.ifr_addr, &in6m->in6m_addr, 0, 0, 0);
  746                 (*in6m->in6m_ifp->if_ioctl)(in6m->in6m_ifp, SIOCDELMULTI, &ifr);
  747                 callout_destroy(&in6m->in6m_timer_ch);
  748                 free(in6m, M_IPMADDR);
  749         }
  750         splx(s);
  751 }
  752 
  753 
  754 struct in6_multi_mship *
  755 in6_joingroup(struct ifnet *ifp, struct in6_addr *addr, 
  756         int *errorp, int timer)
  757 {
  758         struct in6_multi_mship *imm;
  759 
  760         imm = malloc(sizeof(*imm), M_IPMADDR, M_NOWAIT);
  761         if (!imm) {
  762                 *errorp = ENOBUFS;
  763                 return NULL;
  764         }
  765 
  766         memset(imm, 0, sizeof(*imm));
  767         imm->i6mm_maddr = in6_addmulti(addr, ifp, errorp, timer);
  768         if (!imm->i6mm_maddr) {
  769                 /* *errorp is already set */
  770                 free(imm, M_IPMADDR);
  771                 return NULL;
  772         }
  773         return imm;
  774 }
  775 
  776 int
  777 in6_leavegroup(struct in6_multi_mship *imm)
  778 {
  779 
  780         if (imm->i6mm_maddr) {
  781                 in6_delmulti(imm->i6mm_maddr);
  782         }
  783         free(imm, M_IPMADDR);
  784         return 0;
  785 }
  786 
  787 
  788 /*
  789  * Multicast address kludge:
  790  * If there were any multicast addresses attached to this interface address,
  791  * either move them to another address on this interface, or save them until
  792  * such time as this interface is reconfigured for IPv6.
  793  */
  794 void
  795 in6_savemkludge(struct in6_ifaddr *oia)
  796 {
  797         struct in6_ifaddr *ia;
  798         struct in6_multi *in6m;
  799 
  800         IFP_TO_IA6(oia->ia_ifp, ia);
  801         if (ia) {       /* there is another address */
  802                 KASSERT(ia != oia);
  803                 while ((in6m = LIST_FIRST(&oia->ia6_multiaddrs)) != NULL) {
  804                         LIST_REMOVE(in6m, in6m_entry);
  805                         IFAREF(&ia->ia_ifa);
  806                         IFAFREE(&in6m->in6m_ia->ia_ifa);
  807                         in6m->in6m_ia = ia;
  808                         LIST_INSERT_HEAD(&ia->ia6_multiaddrs, in6m, in6m_entry);
  809                 }
  810         } else {        /* last address on this if deleted, save */
  811                 struct multi6_kludge *mk;
  812 
  813                 LIST_FOREACH(mk, &in6_mk, mk_entry) {
  814                         if (mk->mk_ifp == oia->ia_ifp)
  815                                 break;
  816                 }
  817                 if (mk == NULL) /* this should not happen! */
  818                         panic("in6_savemkludge: no kludge space");
  819 
  820                 while ((in6m = LIST_FIRST(&oia->ia6_multiaddrs)) != NULL) {
  821                         LIST_REMOVE(in6m, in6m_entry);
  822                         IFAFREE(&in6m->in6m_ia->ia_ifa); /* release reference */
  823                         in6m->in6m_ia = NULL;
  824                         LIST_INSERT_HEAD(&mk->mk_head, in6m, in6m_entry);
  825                 }
  826         }
  827 }
  828 
  829 /*
  830  * Continuation of multicast address hack:
  831  * If there was a multicast group list previously saved for this interface,
  832  * then we re-attach it to the first address configured on the i/f.
  833  */
  834 void
  835 in6_restoremkludge(struct in6_ifaddr *ia, struct ifnet *ifp)
  836 {
  837         struct multi6_kludge *mk;
  838         struct in6_multi *in6m;
  839 
  840         LIST_FOREACH(mk, &in6_mk, mk_entry) {
  841                 if (mk->mk_ifp == ifp)
  842                         break;
  843         }
  844         if (mk == NULL)
  845                 return;
  846         while ((in6m = LIST_FIRST(&mk->mk_head)) != NULL) {
  847                 LIST_REMOVE(in6m, in6m_entry);
  848                 in6m->in6m_ia = ia;
  849                 IFAREF(&ia->ia_ifa);
  850                 LIST_INSERT_HEAD(&ia->ia6_multiaddrs, in6m, in6m_entry);
  851         }
  852 }
  853 
  854 /*
  855  * Allocate space for the kludge at interface initialization time.
  856  * Formerly, we dynamically allocated the space in in6_savemkludge() with
  857  * malloc(M_WAITOK).  However, it was wrong since the function could be called
  858  * under an interrupt context (software timer on address lifetime expiration).
  859  * Also, we cannot just give up allocating the strucutre, since the group
  860  * membership structure is very complex and we need to keep it anyway.
  861  * Of course, this function MUST NOT be called under an interrupt context.
  862  * Specifically, it is expected to be called only from in6_ifattach(), though
  863  * it is a global function.
  864  */
  865 void
  866 in6_createmkludge(struct ifnet *ifp)
  867 {
  868         struct multi6_kludge *mk;
  869 
  870         LIST_FOREACH(mk, &in6_mk, mk_entry) {
  871                 /* If we've already had one, do not allocate. */
  872                 if (mk->mk_ifp == ifp)
  873                         return;
  874         }
  875 
  876         mk = malloc(sizeof(*mk), M_IPMADDR, M_WAITOK);
  877 
  878         memset(mk, 0, sizeof(*mk));
  879         LIST_INIT(&mk->mk_head);
  880         mk->mk_ifp = ifp;
  881         LIST_INSERT_HEAD(&in6_mk, mk, mk_entry);
  882 }
  883 
  884 void
  885 in6_purgemkludge(struct ifnet *ifp)
  886 {
  887         struct multi6_kludge *mk;
  888         struct in6_multi *in6m, *next;
  889 
  890         LIST_FOREACH(mk, &in6_mk, mk_entry) {
  891                 if (mk->mk_ifp == ifp)
  892                         break;
  893         }
  894         if (mk == NULL)
  895                 return;
  896 
  897         /* leave from all multicast groups joined */
  898         for (in6m = LIST_FIRST(&mk->mk_head); in6m != NULL; in6m = next) {
  899                 next = LIST_NEXT(in6m, in6m_entry);
  900                 in6_delmulti(in6m);
  901         }
  902         LIST_REMOVE(mk, mk_entry);
  903         free(mk, M_IPMADDR);
  904 }

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