FreeBSD/Linux Kernel Cross Reference
sys/netinet6/mld6.c

     /*      $NetBSD: mld6.c,v 1.36.2.1 2008/08/23 17:02:31 bouyer Exp $     */
     /*      $KAME: mld6.c,v 1.25 2001/01/16 14:14:18 itojun Exp $   */
     
     /*
      * Copyright (C) 1998 WIDE Project.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the project nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    /*
     * Copyright (c) 1992, 1993
     *      The Regents of the University of California.  All rights reserved.
     *
     * This code is derived from software contributed to Berkeley by
     * Stephen Deering of Stanford University.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
     */
    
    /*
     * Copyright (c) 1988 Stephen Deering.
     *
     * This code is derived from software contributed to Berkeley by
     * Stephen Deering of Stanford University.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
    *
    *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
    */
   
   #include <sys/cdefs.h>
   __KERNEL_RCSID(0, "$NetBSD: mld6.c,v 1.36.2.1 2008/08/23 17:02:31 bouyer Exp $");
   
   #include "opt_inet.h"
   
   #include <sys/param.h>
   #include <sys/systm.h>
   #include <sys/mbuf.h>
   #include <sys/socket.h>
   #include <sys/protosw.h>
   #include <sys/syslog.h>
   #include <sys/sysctl.h>
   #include <sys/kernel.h>
   #include <sys/callout.h>
   
   #include <net/if.h>
   
   #include <netinet/in.h>
   #include <netinet/in_var.h>
   #include <netinet6/in6_var.h>
   #include <netinet/ip6.h>
   #include <netinet6/ip6_var.h>
   #include <netinet6/scope6_var.h>
   #include <netinet/icmp6.h>
   #include <netinet6/mld6_var.h>
   
   #include <net/net_osdep.h>
   
   
   /*
    * This structure is used to keep track of in6_multi chains which belong to
    * deleted interface addresses.
    */
   static LIST_HEAD(, multi6_kludge) in6_mk; /* XXX BSS initialization */
   
   struct multi6_kludge {
           LIST_ENTRY(multi6_kludge) mk_entry;
           struct ifnet *mk_ifp;
           struct in6_multihead mk_head;
   };
   
   
   /*
    * Protocol constants
    */
   
   /*
    * time between repetitions of a node's initial report of interest in a
    * multicast address(in seconds)
    */
   #define MLD_UNSOLICITED_REPORT_INTERVAL 10
   
   static struct ip6_pktopts ip6_opts;
   
   static void mld_start_listening(struct in6_multi *);
   static void mld_stop_listening(struct in6_multi *);
   
   static struct mld_hdr * mld_allocbuf(struct mbuf **, int, struct in6_multi *,
           int);
   static void mld_sendpkt(struct in6_multi *, int, const struct in6_addr *);
   static void mld_starttimer(struct in6_multi *);
   static void mld_stoptimer(struct in6_multi *);
   static void mld_timeo(struct in6_multi *);
   static u_long mld_timerresid(struct in6_multi *);
   
   void
   mld_init()
   {
           static u_int8_t hbh_buf[8];
           struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
           u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
   
           /* ip6h_nxt will be fill in later */
           hbh->ip6h_len = 0;      /* (8 >> 3) - 1 */
   
           /* XXX: grotty hard coding... */
           hbh_buf[2] = IP6OPT_PADN;       /* 2 byte padding */
           hbh_buf[3] = 0;
           hbh_buf[4] = IP6OPT_RTALERT;
           hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
           bcopy((caddr_t)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));
   
           ip6_opts.ip6po_hbh = hbh;
           /* We will specify the hoplimit by a multicast option. */
           ip6_opts.ip6po_hlim = -1;
   }
   
   static void
   mld_starttimer(in6m)
           struct in6_multi *in6m;
   {
           struct timeval now;
   
           microtime(&now);
           in6m->in6m_timer_expire.tv_sec = now.tv_sec + in6m->in6m_timer / hz;
           in6m->in6m_timer_expire.tv_usec = now.tv_usec +
               (in6m->in6m_timer % hz) * (1000000 / hz);
           if (in6m->in6m_timer_expire.tv_usec > 1000000) {
                   in6m->in6m_timer_expire.tv_sec++;
                   in6m->in6m_timer_expire.tv_usec -= 1000000;
           }
   
           /* start or restart the timer */
           callout_reset(in6m->in6m_timer_ch, in6m->in6m_timer,
               (void (*) __P((void *)))mld_timeo, in6m);
   }
   
   static void
   mld_stoptimer(in6m)
           struct in6_multi *in6m;
   {
           if (in6m->in6m_timer == IN6M_TIMER_UNDEF)
                   return;
   
           callout_stop(in6m->in6m_timer_ch);
   
           in6m->in6m_timer = IN6M_TIMER_UNDEF;
   }
   
   static void
   mld_timeo(in6m)
           struct in6_multi *in6m;
   {
           int s = splsoftnet();
   
           in6m->in6m_timer = IN6M_TIMER_UNDEF;
   
           callout_stop(in6m->in6m_timer_ch);
   
           switch (in6m->in6m_state) {
           case MLD_REPORTPENDING:
                   mld_start_listening(in6m);
                   break;
           default:
                   mld_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
                   break;
           }
   
           splx(s);
   }
   
   static u_long
   mld_timerresid(in6m)
           struct in6_multi *in6m;
   {
           struct timeval now, diff;
   
           microtime(&now);
   
           if (now.tv_sec > in6m->in6m_timer_expire.tv_sec ||
               (now.tv_sec == in6m->in6m_timer_expire.tv_sec &&
               now.tv_usec > in6m->in6m_timer_expire.tv_usec)) {
                   return (0);
           }
           diff = in6m->in6m_timer_expire;
           diff.tv_sec -= now.tv_sec;
           diff.tv_usec -= now.tv_usec;
           if (diff.tv_usec < 0) {
                   diff.tv_sec--;
                   diff.tv_usec += 1000000;
           }
   
           /* return the remaining time in milliseconds */
           return diff.tv_sec * 1000 + diff.tv_usec / 1000;
   }
   
   static void
   mld_start_listening(in6m)
           struct in6_multi *in6m;
   {
           struct in6_addr all_in6;
   
           /*
            * RFC2710 page 10:
            * The node never sends a Report or Done for the link-scope all-nodes
            * address.
            * MLD messages are never sent for multicast addresses whose scope is 0
            * (reserved) or 1 (node-local).
            */
           all_in6 = in6addr_linklocal_allnodes;
           if (in6_setscope(&all_in6, in6m->in6m_ifp, NULL)) {
                   /* XXX: this should not happen! */
                   in6m->in6m_timer = 0;
                   in6m->in6m_state = MLD_OTHERLISTENER;
           }
           if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
               IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) < IPV6_ADDR_SCOPE_LINKLOCAL) {
                   in6m->in6m_timer = IN6M_TIMER_UNDEF;
                   in6m->in6m_state = MLD_OTHERLISTENER;
           } else {
                   mld_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
                   in6m->in6m_timer = arc4random() %
                       (MLD_UNSOLICITED_REPORT_INTERVAL * hz);
                   in6m->in6m_state = MLD_IREPORTEDLAST;
   
                   mld_starttimer(in6m);
           }
   }
   
   static void
   mld_stop_listening(in6m)
           struct in6_multi *in6m;
   {
           struct in6_addr allnode, allrouter;
   
           allnode = in6addr_linklocal_allnodes;
           if (in6_setscope(&allnode, in6m->in6m_ifp, NULL)) {
                   /* XXX: this should not happen! */
                   return;
           }
           allrouter = in6addr_linklocal_allrouters;
           if (in6_setscope(&allrouter, in6m->in6m_ifp, NULL)) {
                   /* XXX impossible */
                   return;
           }
   
           if (in6m->in6m_state == MLD_IREPORTEDLAST &&
               (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &allnode)) &&
               IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) >
               IPV6_ADDR_SCOPE_INTFACELOCAL) {
                   mld_sendpkt(in6m, MLD_LISTENER_DONE, &allrouter);
           }
   }
   
   void
   mld_input(m, off)
           struct mbuf *m;
           int off;
   {
           struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
           struct mld_hdr *mldh;
           struct ifnet *ifp = m->m_pkthdr.rcvif;
           struct in6_multi *in6m = NULL;
           struct in6_addr mld_addr, all_in6;
           struct in6_ifaddr *ia;
           u_long timer = 0;       /* timer value in the MLD query header */
   
           IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
           if (mldh == NULL) {
                   icmp6stat.icp6s_tooshort++;
                   return;
           }
   
           /* source address validation */
           ip6 = mtod(m, struct ip6_hdr *);/* in case mpullup */
           if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
                   /*
                    * RFC3590 allows the IPv6 unspecified address as the source
                    * address of MLD report and done messages.  However, as this
                    * same document says, this special rule is for snooping
                    * switches and the RFC requires routers to discard MLD packets
                    * with the unspecified source address.  The RFC only talks
                    * about hosts receiving an MLD query or report in Security
                    * Considerations, but this is probably the correct intention.
                    * RFC3590 does not talk about other cases than link-local and
                    * the unspecified source addresses, but we believe the same
                    * rule should be applied.
                    * As a result, we only allow link-local addresses as the
                    * source address; otherwise, simply discard the packet.
                    */
   #if 0
                   /*
                    * XXX: do not log in an input path to avoid log flooding,
                    * though RFC3590 says "SHOULD log" if the source of a query
                    * is the unspecified address.
                    */
                   log(LOG_INFO,
                       "mld_input: src %s is not link-local (grp=%s)\n",
                       ip6_sprintf(&ip6->ip6_src), ip6_sprintf(&mldh->mld_addr));
   #endif
                   m_freem(m);
                   return;
           }
   
           /*
            * make a copy for local work (in6_setscope() may modify the 1st arg)
            */
           mld_addr = mldh->mld_addr;
           if (in6_setscope(&mld_addr, ifp, NULL)) {
                   /* XXX: this should not happen! */
                   m_free(m);
                   return;
           }
   
           /*
            * In the MLD specification, there are 3 states and a flag.
            *
            * In Non-Listener state, we simply don't have a membership record.
            * In Delaying Listener state, our timer is running (in6m->in6m_timer)
            * In Idle Listener state, our timer is not running 
            * (in6m->in6m_timer==IN6M_TIMER_UNDEF)
            *
            * The flag is in6m->in6m_state, it is set to MLD_OTHERLISTENER if
            * we have heard a report from another member, or MLD_IREPORTEDLAST
            * if we sent the last report.
            */
           switch (mldh->mld_type) {
           case MLD_LISTENER_QUERY:
                   if (ifp->if_flags & IFF_LOOPBACK)
                           break;
   
                   if (!IN6_IS_ADDR_UNSPECIFIED(&mld_addr) &&
                       !IN6_IS_ADDR_MULTICAST(&mld_addr))
                           break;  /* print error or log stat? */
   
                   all_in6 = in6addr_linklocal_allnodes;
                   if (in6_setscope(&all_in6, ifp, NULL)) {
                           /* XXX: this should not happen! */
                           break;
                   }
   
                   /*
                    * - Start the timers in all of our membership records
                    *   that the query applies to for the interface on
                    *   which the query arrived excl. those that belong
                    *   to the "all-nodes" group (ff02::1).
                    * - Restart any timer that is already running but has
                    *   a value longer than the requested timeout.
                    * - Use the value specified in the query message as
                    *   the maximum timeout.
                    */
                   timer = ntohs(mldh->mld_maxdelay);
   
                   IFP_TO_IA6(ifp, ia);
                   if (ia == NULL)
                           break;
   
                   LIST_FOREACH(in6m, &ia->ia6_multiaddrs, in6m_entry) {
                           if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_in6) ||
                               IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
                               IPV6_ADDR_SCOPE_LINKLOCAL)
                                   continue;
   
                           if (in6m->in6m_state == MLD_REPORTPENDING)
                                   continue; /* we are not yet ready */
   
                           if (!IN6_IS_ADDR_UNSPECIFIED(&mld_addr) &&
                               !IN6_ARE_ADDR_EQUAL(&mld_addr, &in6m->in6m_addr))
                                   continue;
   
                           if (timer == 0) {
                                   /* send a report immediately */
                                   mld_stoptimer(in6m);
                                   mld_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
                                   in6m->in6m_state = MLD_IREPORTEDLAST;
                           } else if (in6m->in6m_timer == IN6M_TIMER_UNDEF ||
                               mld_timerresid(in6m) > timer) {
                                   in6m->in6m_timer =
                                      1 + (arc4random() % timer) * hz / 1000;
                                   mld_starttimer(in6m);
                           }
                   }
                   break;
   
           case MLD_LISTENER_REPORT:
                   /*
                    * For fast leave to work, we have to know that we are the
                    * last person to send a report for this group.  Reports
                    * can potentially get looped back if we are a multicast
                    * router, so discard reports sourced by me.
                    * Note that it is impossible to check IFF_LOOPBACK flag of
                    * ifp for this purpose, since ip6_mloopback pass the physical
                    * interface to looutput.
                    */
                   if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
                           break;
   
                   if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
                           break;
   
                   /*
                    * If we belong to the group being reported, stop
                    * our timer for that group.
                    */
                   IN6_LOOKUP_MULTI(mld_addr, ifp, in6m);
                   if (in6m) {
                           mld_stoptimer(in6m); /* transit to idle state */
                           in6m->in6m_state = MLD_OTHERLISTENER; /* clear flag */
                   }
                   break;
           default:                /* this is impossible */
   #if 0
                   /*
                    * this case should be impossible because of filtering in
                    * icmp6_input().  But we explicitly disabled this part
                    * just in case.
                    */
                   log(LOG_ERR, "mld_input: illegal type(%d)", mldh->mld_type);
   #endif
                   break;
           }
   
           m_freem(m);
   }
   
   static void
   mld_sendpkt(in6m, type, dst)
           struct in6_multi *in6m;
           int type;
           const struct in6_addr *dst;
   {
           struct mbuf *mh;
           struct mld_hdr *mldh;
           struct ip6_hdr *ip6 = NULL;
           struct ip6_moptions im6o;
           struct in6_ifaddr *ia = NULL;
           struct ifnet *ifp = in6m->in6m_ifp;
           int ignflags;
   
           /*
            * At first, find a link local address on the outgoing interface
            * to use as the source address of the MLD packet.
            * We do not reject tentative addresses for MLD report to deal with
            * the case where we first join a link-local address.
            */
           ignflags = (IN6_IFF_NOTREADY|IN6_IFF_ANYCAST) & ~IN6_IFF_TENTATIVE;
           if ((ia = in6ifa_ifpforlinklocal(ifp, ignflags)) == NULL)
                   return;
           if ((ia->ia6_flags & IN6_IFF_TENTATIVE))
                   ia = NULL;
   
           /* Allocate two mbufs to store IPv6 header and MLD header */
           mldh = mld_allocbuf(&mh, sizeof(struct mld_hdr), in6m, type);
           if (mldh == NULL)
                   return;
   
           /* fill src/dst here */
           ip6 = mtod(mh, struct ip6_hdr *);
           ip6->ip6_src = ia ? ia->ia_addr.sin6_addr : in6addr_any;
           ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
   
           mldh->mld_addr = in6m->in6m_addr;
           in6_clearscope(&mldh->mld_addr); /* XXX */
           mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
               sizeof(struct mld_hdr));
   
           /* construct multicast option */
           memset(&im6o, 0, sizeof(im6o));
           im6o.im6o_multicast_ifp = ifp;
           im6o.im6o_multicast_hlim = 1;
   
           /*
            * Request loopback of the report if we are acting as a multicast
            * router, so that the process-level routing daemon can hear it.
            */
           im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
   
           /* increment output statictics */
           icmp6stat.icp6s_outhist[type]++;
           icmp6_ifstat_inc(ifp, ifs6_out_msg);
           switch (type) {
           case MLD_LISTENER_QUERY:
                   icmp6_ifstat_inc(ifp, ifs6_out_mldquery);
                   break;
           case MLD_LISTENER_REPORT:
                   icmp6_ifstat_inc(ifp, ifs6_out_mldreport);
                   break;
           case MLD_LISTENER_DONE:
                   icmp6_ifstat_inc(ifp, ifs6_out_mlddone);
                   break;
           }
   
           ip6_output(mh, &ip6_opts, NULL, ia ? 0 : IPV6_UNSPECSRC,
               &im6o, (struct socket *)NULL, NULL);
   }
   
   static struct mld_hdr *
   mld_allocbuf(struct mbuf **mh, int len, struct in6_multi *in6m,
       int type)
   {
           struct mbuf *md;
           struct mld_hdr *mldh;
           struct ip6_hdr *ip6;
   
           /*
            * Allocate mbufs to store ip6 header and MLD header.
            * We allocate 2 mbufs and make chain in advance because
            * it is more convenient when inserting the hop-by-hop option later.
            */
           MGETHDR(*mh, M_DONTWAIT, MT_HEADER);
           if (*mh == NULL)
                   return NULL;
           MGET(md, M_DONTWAIT, MT_DATA);
           if (md == NULL) {
                   m_free(*mh);
                   *mh = NULL;
                   return NULL;
           }
           (*mh)->m_next = md;
           md->m_next = NULL;
   
           (*mh)->m_pkthdr.rcvif = NULL;
           (*mh)->m_pkthdr.len = sizeof(struct ip6_hdr) + len;
           (*mh)->m_len = sizeof(struct ip6_hdr);
           MH_ALIGN(*mh, sizeof(struct ip6_hdr));
   
           /* fill in the ip6 header */
           ip6 = mtod(*mh, struct ip6_hdr *);
           memset(ip6, 0, sizeof(*ip6));
           ip6->ip6_flow = 0;
           ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
           ip6->ip6_vfc |= IPV6_VERSION;
           /* ip6_plen will be set later */
           ip6->ip6_nxt = IPPROTO_ICMPV6;
           /* ip6_hlim will be set by im6o.im6o_multicast_hlim */
           /* ip6_src/dst will be set by mld_sendpkt() or mld_sendbuf() */
   
           /* fill in the MLD header as much as possible */
           md->m_len = len;
           mldh = mtod(md, struct mld_hdr *);
           memset(mldh, 0, len);
           mldh->mld_type = type;
           return mldh;
   }
   
   /*
    * Add an address to the list of IP6 multicast addresses for a given interface.
    */
   struct  in6_multi *
   in6_addmulti(maddr6, ifp, errorp, timer)
           struct in6_addr *maddr6;
           struct ifnet *ifp;
           int *errorp, timer;
   {
           struct  in6_ifaddr *ia;
           struct  in6_ifreq ifr;
           struct  in6_multi *in6m;
           int     s = splsoftnet();
   
           *errorp = 0;
   
           /*
            * See if address already in list.
            */
           IN6_LOOKUP_MULTI(*maddr6, ifp, in6m);
           if (in6m != NULL) {
                   /*
                    * Found it; just increment the refrence count.
                    */
                   in6m->in6m_refcount++;
           } else {
                   /*
                    * New address; allocate a new multicast record
                    * and link it into the interface's multicast list.
                    */
                   in6m = (struct in6_multi *)
                           malloc(sizeof(*in6m), M_IPMADDR, M_NOWAIT);
                   if (in6m == NULL) {
                           splx(s);
                           *errorp = ENOBUFS;
                           return (NULL);
                   }
   
                   memset(in6m, 0, sizeof(*in6m));
                   in6m->in6m_addr = *maddr6;
                   in6m->in6m_ifp = ifp;
                   in6m->in6m_refcount = 1;
                   in6m->in6m_timer = IN6M_TIMER_UNDEF;
                   in6m->in6m_timer_ch =
                       malloc(sizeof(*in6m->in6m_timer_ch), M_IPMADDR, M_NOWAIT);
                   if (in6m->in6m_timer_ch == NULL) {
                           free(in6m, M_IPMADDR);
                           splx(s);
                           return (NULL);
                   }
                   IFP_TO_IA6(ifp, ia);
                   if (ia == NULL) {
                           /* leaks in6m_timer_ch */
                           free(in6m, M_IPMADDR);
                           splx(s);
                           *errorp = EADDRNOTAVAIL; /* appropriate? */
                           return (NULL);
                   }
                   in6m->in6m_ia = ia;
                   IFAREF(&ia->ia_ifa); /* gain a reference */
                   LIST_INSERT_HEAD(&ia->ia6_multiaddrs, in6m, in6m_entry);
   
                   /*
                    * Ask the network driver to update its multicast reception
                    * filter appropriately for the new address.
                    */
                   memset(&ifr.ifr_addr, 0, sizeof(struct sockaddr_in6));
                   ifr.ifr_addr.sin6_family = AF_INET6;
                   ifr.ifr_addr.sin6_len = sizeof(struct sockaddr_in6);
                   ifr.ifr_addr.sin6_addr = *maddr6;
                   if (ifp->if_ioctl == NULL)
                           *errorp = ENXIO; /* XXX: appropriate? */
                   else
                           *errorp = (*ifp->if_ioctl)(ifp, SIOCADDMULTI,
                               (caddr_t)&ifr);
                   if (*errorp) {
                           LIST_REMOVE(in6m, in6m_entry);
                           /* leaks in6m_timer_ch */
                           free(in6m, M_IPMADDR);
                           IFAFREE(&ia->ia_ifa);
                           splx(s);
                           return (NULL);
                   }
   
                   callout_init(in6m->in6m_timer_ch);
                   in6m->in6m_timer = timer;
                   if (in6m->in6m_timer > 0) {
                           in6m->in6m_state = MLD_REPORTPENDING;
                           mld_starttimer(in6m);
   
                           splx(s);
                           return (in6m);
                   }
   
                   /*
                    * Let MLD6 know that we have joined a new IP6 multicast
                    * group.
                    */
                   mld_start_listening(in6m);
           }
           splx(s);
           return (in6m);
   }
   
   /*
    * Delete a multicast address record.
    */
   void
   in6_delmulti(in6m)
           struct in6_multi *in6m;
   {
           struct  in6_ifreq ifr;
           struct  in6_ifaddr *ia;
           int     s = splsoftnet();
   
           mld_stoptimer(in6m);
   
           if (--in6m->in6m_refcount == 0) {
                   /*
                    * No remaining claims to this record; let MLD6 know
                    * that we are leaving the multicast group.
                    */
                   mld_stop_listening(in6m);
   
                   /*
                    * Unlink from list.
                    */
                   LIST_REMOVE(in6m, in6m_entry);
                   if (in6m->in6m_ia != NULL) {
                           IFAFREE(&in6m->in6m_ia->ia_ifa); /* release reference */
                           in6m->in6m_ia = NULL;
                   }
   
                   /*
                    * Delete all references of this multicasting group from
                    * the membership arrays
                    */
                   for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
                           struct in6_multi_mship *imm;
                           LIST_FOREACH(imm, &ia->ia6_memberships, i6mm_chain) {
                                   if (imm->i6mm_maddr == in6m)
                                           imm->i6mm_maddr = NULL;
                           }
                   }
   
                   /*
                    * Notify the network driver to update its multicast
                    * reception filter.
                    */
                   memset(&ifr.ifr_addr, 0, sizeof(struct sockaddr_in6));
                   ifr.ifr_addr.sin6_family = AF_INET6;
                   ifr.ifr_addr.sin6_len = sizeof(struct sockaddr_in6);
                   ifr.ifr_addr.sin6_addr = in6m->in6m_addr;
                   (*in6m->in6m_ifp->if_ioctl)(in6m->in6m_ifp,
                       SIOCDELMULTI, (caddr_t)&ifr);
                   free(in6m->in6m_timer_ch, M_IPMADDR);
                   free(in6m, M_IPMADDR);
           }
           splx(s);
   }
   
   
   struct in6_multi_mship *
   in6_joingroup(ifp, addr, errorp, timer)
           struct ifnet *ifp;
           struct in6_addr *addr;
           int *errorp, timer;
   {
           struct in6_multi_mship *imm;
   
           imm = malloc(sizeof(*imm), M_IPMADDR, M_NOWAIT);
           if (!imm) {
                   *errorp = ENOBUFS;
                   return NULL;
           }
   
           memset(imm, 0, sizeof(*imm));
           imm->i6mm_maddr = in6_addmulti(addr, ifp, errorp, timer);
           if (!imm->i6mm_maddr) {
                   /* *errorp is already set */
                   free(imm, M_IPMADDR);
                   return NULL;
           }
           return imm;
   }
   
   int
   in6_leavegroup(imm)
           struct in6_multi_mship *imm;
   {
   
           if (imm->i6mm_maddr) {
                   in6_delmulti(imm->i6mm_maddr);
           }
           free(imm, M_IPMADDR);
           return 0;
   }
   
   
   /*
    * Multicast address kludge:
    * If there were any multicast addresses attached to this interface address,
    * either move them to another address on this interface, or save them until
    * such time as this interface is reconfigured for IPv6.
    */
   void
   in6_savemkludge(oia)
           struct in6_ifaddr *oia;
   {
           struct in6_ifaddr *ia;
           struct in6_multi *in6m;
   
           IFP_TO_IA6(oia->ia_ifp, ia);
           if (ia) {       /* there is another address */
                   KASSERT(ia != oia);
                   while ((in6m = LIST_FIRST(&oia->ia6_multiaddrs)) != NULL) {
                           LIST_REMOVE(in6m, in6m_entry);
                           IFAREF(&ia->ia_ifa);
                           IFAFREE(&in6m->in6m_ia->ia_ifa);
                           in6m->in6m_ia = ia;
                           LIST_INSERT_HEAD(&ia->ia6_multiaddrs, in6m, in6m_entry);
                   }
           } else {        /* last address on this if deleted, save */
                   struct multi6_kludge *mk;
   
                   LIST_FOREACH(mk, &in6_mk, mk_entry) {
                           if (mk->mk_ifp == oia->ia_ifp)
                                   break;
                   }
                   if (mk == NULL) /* this should not happen! */
                           panic("in6_savemkludge: no kludge space");
   
                   while ((in6m = LIST_FIRST(&oia->ia6_multiaddrs)) != NULL) {
                           LIST_REMOVE(in6m, in6m_entry);
                           IFAFREE(&in6m->in6m_ia->ia_ifa); /* release reference */
                           in6m->in6m_ia = NULL;
                           LIST_INSERT_HEAD(&mk->mk_head, in6m, in6m_entry);
                   }
           }
   }
   
   /*
    * Continuation of multicast address hack:
    * If there was a multicast group list previously saved for this interface,
    * then we re-attach it to the first address configured on the i/f.
    */
   void
   in6_restoremkludge(ia, ifp)
           struct in6_ifaddr *ia;
           struct ifnet *ifp;
   {
           struct multi6_kludge *mk;
           struct in6_multi *in6m;
   
           LIST_FOREACH(mk, &in6_mk, mk_entry) {
                   if (mk->mk_ifp == ifp)
                           break;
           }
           if (mk == NULL)
                   return;
           while ((in6m = LIST_FIRST(&mk->mk_head)) != NULL) {
                   LIST_REMOVE(in6m, in6m_entry);
                   in6m->in6m_ia = ia;
                   IFAREF(&ia->ia_ifa);
                   LIST_INSERT_HEAD(&ia->ia6_multiaddrs, in6m, in6m_entry);
           }
   }
   
   /*
    * Allocate space for the kludge at interface initialization time.
    * Formerly, we dynamically allocated the space in in6_savemkludge() with
    * malloc(M_WAITOK).  However, it was wrong since the function could be called
    * under an interrupt context (software timer on address lifetime expiration).
    * Also, we cannot just give up allocating the strucutre, since the group
    * membership structure is very complex and we need to keep it anyway.
    * Of course, this function MUST NOT be called under an interrupt context.
    * Specifically, it is expected to be called only from in6_ifattach(), though
    * it is a global function.
    */
   void
   in6_createmkludge(ifp)
           struct ifnet *ifp;
   {
           struct multi6_kludge *mk;
   
           LIST_FOREACH(mk, &in6_mk, mk_entry) {
                   /* If we've already had one, do not allocate. */
                   if (mk->mk_ifp == ifp)
                           return;
           }
   
           mk = malloc(sizeof(*mk), M_IPMADDR, M_WAITOK);
   
           memset(mk, 0, sizeof(*mk));
           LIST_INIT(&mk->mk_head);
           mk->mk_ifp = ifp;
           LIST_INSERT_HEAD(&in6_mk, mk, mk_entry);
   }
   
   void
   in6_purgemkludge(ifp)
           struct ifnet *ifp;
   {
           struct multi6_kludge *mk;
           struct in6_multi *in6m, *next;
   
           LIST_FOREACH(mk, &in6_mk, mk_entry) {
                   if (mk->mk_ifp == ifp)
                           break;
           }
           if (mk == NULL)
                   return;
   
           /* leave from all multicast groups joined */
           for (in6m = LIST_FIRST(&mk->mk_head); in6m != NULL; in6m = next) {
                   next = LIST_NEXT(in6m, in6m_entry);
                   in6_delmulti(in6m);
           }
           LIST_REMOVE(mk, mk_entry);
           free(mk, M_IPMADDR);
   }

Cache object: 3f01a4eadd4c2c00d19b76d721c53228