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

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    1 /*      $FreeBSD: releng/5.2/sys/netinet6/mld6.c 121808 2003-10-31 16:07:15Z ume $      */
    2 /*      $KAME: mld6.c,v 1.27 2001/04/04 05:17:30 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) 1988 Stephen Deering.
   35  * Copyright (c) 1992, 1993
   36  *      The Regents of the University of California.  All rights reserved.
   37  *
   38  * This code is derived from software contributed to Berkeley by
   39  * Stephen Deering of Stanford University.
   40  *
   41  * Redistribution and use in source and binary forms, with or without
   42  * modification, are permitted provided that the following conditions
   43  * are met:
   44  * 1. Redistributions of source code must retain the above copyright
   45  *    notice, this list of conditions and the following disclaimer.
   46  * 2. Redistributions in binary form must reproduce the above copyright
   47  *    notice, this list of conditions and the following disclaimer in the
   48  *    documentation and/or other materials provided with the distribution.
   49  * 3. All advertising materials mentioning features or use of this software
   50  *    must display the following acknowledgement:
   51  *      This product includes software developed by the University of
   52  *      California, Berkeley and its contributors.
   53  * 4. Neither the name of the University nor the names of its contributors
   54  *    may be used to endorse or promote products derived from this software
   55  *    without specific prior written permission.
   56  *
   57  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   58  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   59  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   60  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   61  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   62  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   63  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   64  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   65  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   66  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   67  * SUCH DAMAGE.
   68  *
   69  *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
   70  */
   71 
   72 #include "opt_inet.h"
   73 #include "opt_inet6.h"
   74 
   75 #include <sys/param.h>
   76 #include <sys/systm.h>
   77 #include <sys/mbuf.h>
   78 #include <sys/socket.h>
   79 #include <sys/protosw.h>
   80 #include <sys/syslog.h>
   81 
   82 #include <net/if.h>
   83 
   84 #include <netinet/in.h>
   85 #include <netinet/in_var.h>
   86 #include <netinet/ip6.h>
   87 #include <netinet6/ip6_var.h>
   88 #include <netinet/icmp6.h>
   89 #include <netinet6/mld6_var.h>
   90 
   91 #include <net/net_osdep.h>
   92 
   93 /*
   94  * Protocol constants
   95  */
   96 
   97 /* denotes that the MLD max response delay field specifies time in milliseconds */
   98 #define MLD_TIMER_SCALE 1000
   99 /*
  100  * time between repetitions of a node's initial report of interest in a
  101  * multicast address(in seconds)
  102  */
  103 #define MLD_UNSOLICITED_REPORT_INTERVAL 10
  104 
  105 static struct ip6_pktopts ip6_opts;
  106 static int mld6_timers_are_running;
  107 /* XXX: These are necessary for KAME's link-local hack */
  108 static struct in6_addr mld6_all_nodes_linklocal = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
  109 static struct in6_addr mld6_all_routers_linklocal = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
  110 
  111 static void mld6_sendpkt(struct in6_multi *, int, const struct in6_addr *);
  112 
  113 void
  114 mld6_init()
  115 {
  116         static u_int8_t hbh_buf[8];
  117         struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
  118         u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
  119 
  120         mld6_timers_are_running = 0;
  121 
  122         /* ip6h_nxt will be fill in later */
  123         hbh->ip6h_len = 0;      /* (8 >> 3) - 1 */
  124 
  125         /* XXX: grotty hard coding... */
  126         hbh_buf[2] = IP6OPT_PADN;       /* 2 byte padding */
  127         hbh_buf[3] = 0;
  128         hbh_buf[4] = IP6OPT_ROUTER_ALERT;
  129         hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
  130         bcopy((caddr_t)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));
  131 
  132         init_ip6pktopts(&ip6_opts);
  133         ip6_opts.ip6po_hbh = hbh;
  134 }
  135 
  136 void
  137 mld6_start_listening(in6m)
  138         struct in6_multi *in6m;
  139 {
  140         int s = splnet();
  141 
  142         /*
  143          * RFC2710 page 10:
  144          * The node never sends a Report or Done for the link-scope all-nodes
  145          * address.
  146          * MLD messages are never sent for multicast addresses whose scope is 0
  147          * (reserved) or 1 (node-local).
  148          */
  149         mld6_all_nodes_linklocal.s6_addr16[1] =
  150                 htons(in6m->in6m_ifp->if_index); /* XXX */
  151         if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal) ||
  152             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) < IPV6_ADDR_SCOPE_LINKLOCAL) {
  153                 in6m->in6m_timer = 0;
  154                 in6m->in6m_state = MLD_OTHERLISTENER;
  155         } else {
  156                 mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
  157                 in6m->in6m_timer =
  158                         MLD_RANDOM_DELAY(MLD_UNSOLICITED_REPORT_INTERVAL *
  159                                          PR_FASTHZ);
  160                 in6m->in6m_state = MLD_IREPORTEDLAST;
  161                 mld6_timers_are_running = 1;
  162         }
  163         splx(s);
  164 }
  165 
  166 void
  167 mld6_stop_listening(in6m)
  168         struct in6_multi *in6m;
  169 {
  170         mld6_all_nodes_linklocal.s6_addr16[1] =
  171                 htons(in6m->in6m_ifp->if_index); /* XXX */
  172         mld6_all_routers_linklocal.s6_addr16[1] =
  173                 htons(in6m->in6m_ifp->if_index); /* XXX: necessary when mrouting */
  174 
  175         if (in6m->in6m_state == MLD_IREPORTEDLAST &&
  176             (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal)) &&
  177             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) > IPV6_ADDR_SCOPE_INTFACELOCAL)
  178                 mld6_sendpkt(in6m, MLD_LISTENER_DONE,
  179                              &mld6_all_routers_linklocal);
  180 }
  181 
  182 void
  183 mld6_input(m, off)
  184         struct mbuf *m;
  185         int off;
  186 {
  187         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  188         struct mld_hdr *mldh;
  189         struct ifnet *ifp = m->m_pkthdr.rcvif;
  190         struct in6_multi *in6m;
  191         struct in6_ifaddr *ia;
  192         struct ifmultiaddr *ifma;
  193         int timer;              /* timer value in the MLD query header */
  194 
  195 #ifndef PULLDOWN_TEST
  196         IP6_EXTHDR_CHECK(m, off, sizeof(*mldh),);
  197         mldh = (struct mld_hdr *)(mtod(m, caddr_t) + off);
  198 #else
  199         IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
  200         if (mldh == NULL) {
  201                 icmp6stat.icp6s_tooshort++;
  202                 return;
  203         }
  204 #endif
  205 
  206         /* source address validation */
  207         ip6 = mtod(m, struct ip6_hdr *); /* in case mpullup */
  208         if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
  209                 log(LOG_ERR,
  210                     "mld6_input: src %s is not link-local (grp=%s)\n",
  211                     ip6_sprintf(&ip6->ip6_src),
  212                     ip6_sprintf(&mldh->mld_addr));
  213                 /*
  214                  * spec (RFC2710) does not explicitly
  215                  * specify to discard the packet from a non link-local
  216                  * source address. But we believe it's expected to do so.
  217                  * XXX: do we have to allow :: as source?
  218                  */
  219                 m_freem(m);
  220                 return;
  221         }
  222 
  223         /*
  224          * In the MLD6 specification, there are 3 states and a flag.
  225          *
  226          * In Non-Listener state, we simply don't have a membership record.
  227          * In Delaying Listener state, our timer is running (in6m->in6m_timer)
  228          * In Idle Listener state, our timer is not running (in6m->in6m_timer==0)
  229          *
  230          * The flag is in6m->in6m_state, it is set to MLD_OTHERLISTENER if
  231          * we have heard a report from another member, or MLD_IREPORTEDLAST
  232          * if we sent the last report.
  233          */
  234         switch(mldh->mld_type) {
  235         case MLD_LISTENER_QUERY:
  236                 if (ifp->if_flags & IFF_LOOPBACK)
  237                         break;
  238 
  239                 if (!IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) &&
  240                     !IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
  241                         break;  /* print error or log stat? */
  242                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
  243                         mldh->mld_addr.s6_addr16[1] =
  244                                 htons(ifp->if_index); /* XXX */
  245 
  246                 /*
  247                  * - Start the timers in all of our membership records
  248                  *   that the query applies to for the interface on
  249                  *   which the query arrived excl. those that belong
  250                  *   to the "all-nodes" group (ff02::1).
  251                  * - Restart any timer that is already running but has
  252                  *   A value longer than the requested timeout.
  253                  * - Use the value specified in the query message as
  254                  *   the maximum timeout.
  255                  */
  256                 IFP_TO_IA6(ifp, ia);
  257                 if (ia == NULL)
  258                         break;
  259 
  260                 /*
  261                  * XXX: System timer resolution is too low to handle Max
  262                  * Response Delay, so set 1 to the internal timer even if
  263                  * the calculated value equals to zero when Max Response
  264                  * Delay is positive.
  265                  */
  266                 timer = ntohs(mldh->mld_maxdelay) * PR_FASTHZ / MLD_TIMER_SCALE;
  267                 if (timer == 0 && mldh->mld_maxdelay)
  268                         timer = 1;
  269                 mld6_all_nodes_linklocal.s6_addr16[1] =
  270                         htons(ifp->if_index); /* XXX */
  271 
  272                 TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
  273                         if (ifma->ifma_addr->sa_family != AF_INET6)
  274                                 continue;
  275                         in6m = (struct in6_multi *)ifma->ifma_protospec;
  276 
  277                         if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr,
  278                                         &mld6_all_nodes_linklocal) ||
  279                             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
  280                             IPV6_ADDR_SCOPE_LINKLOCAL)
  281                                 continue;
  282 
  283                         if (IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) ||
  284                             IN6_ARE_ADDR_EQUAL(&mldh->mld_addr,
  285                                                 &in6m->in6m_addr))
  286                         {
  287                                 if (timer == 0) {
  288                                         /* send a report immediately */
  289                                         mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
  290                                                 NULL);
  291                                         in6m->in6m_timer = 0; /* reset timer */
  292                                         in6m->in6m_state = MLD_IREPORTEDLAST;
  293                                 }
  294                                 else if (in6m->in6m_timer == 0 || /*idle state*/
  295                                         in6m->in6m_timer > timer) {
  296                                         in6m->in6m_timer =
  297                                                 MLD_RANDOM_DELAY(timer);
  298                                         mld6_timers_are_running = 1;
  299                                 }
  300                         }
  301                 }
  302 
  303                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
  304                         mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
  305                 break;
  306 
  307         case MLD_LISTENER_REPORT:
  308                 /*
  309                  * For fast leave to work, we have to know that we are the
  310                  * last person to send a report for this group.  Reports
  311                  * can potentially get looped back if we are a multicast
  312                  * router, so discard reports sourced by me.
  313                  * Note that it is impossible to check IFF_LOOPBACK flag of
  314                  * ifp for this purpose, since ip6_mloopback pass the physical
  315                  * interface to looutput.
  316                  */
  317                 if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
  318                         break;
  319 
  320                 if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
  321                         break;
  322 
  323                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
  324                         mldh->mld_addr.s6_addr16[1] =
  325                                 htons(ifp->if_index); /* XXX */
  326                 /*
  327                  * If we belong to the group being reported, stop
  328                  * our timer for that group.
  329                  */
  330                 IN6_LOOKUP_MULTI(mldh->mld_addr, ifp, in6m);
  331                 if (in6m) {
  332                         in6m->in6m_timer = 0; /* transit to idle state */
  333                         in6m->in6m_state = MLD_OTHERLISTENER; /* clear flag */
  334                 }
  335 
  336                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
  337                         mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
  338                 break;
  339         default:                /* this is impossible */
  340                 log(LOG_ERR, "mld6_input: illegal type(%d)", mldh->mld_type);
  341                 break;
  342         }
  343 
  344         m_freem(m);
  345 }
  346 
  347 void
  348 mld6_fasttimeo()
  349 {
  350         struct in6_multi *in6m;
  351         struct in6_multistep step;
  352         int s;
  353 
  354         /*
  355          * Quick check to see if any work needs to be done, in order
  356          * to minimize the overhead of fasttimo processing.
  357          */
  358         if (!mld6_timers_are_running)
  359                 return;
  360 
  361         s = splnet();
  362 
  363         mld6_timers_are_running = 0;
  364         IN6_FIRST_MULTI(step, in6m);
  365         while (in6m != NULL) {
  366                 if (in6m->in6m_timer == 0) {
  367                         /* do nothing */
  368                 } else if (--in6m->in6m_timer == 0) {
  369                         mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
  370                         in6m->in6m_state = MLD_IREPORTEDLAST;
  371                 } else {
  372                         mld6_timers_are_running = 1;
  373                 }
  374                 IN6_NEXT_MULTI(step, in6m);
  375         }
  376 
  377         splx(s);
  378 }
  379 
  380 static void
  381 mld6_sendpkt(in6m, type, dst)
  382         struct in6_multi *in6m;
  383         int type;
  384         const struct in6_addr *dst;
  385 {
  386         struct mbuf *mh, *md;
  387         struct mld_hdr *mldh;
  388         struct ip6_hdr *ip6;
  389         struct ip6_moptions im6o;
  390         struct in6_ifaddr *ia;
  391         struct ifnet *ifp = in6m->in6m_ifp;
  392         struct ifnet *outif = NULL;
  393 
  394         /*
  395          * At first, find a link local address on the outgoing interface
  396          * to use as the source address of the MLD packet.
  397          */
  398         if ((ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST))
  399             == NULL)
  400                 return;
  401 
  402         /*
  403          * Allocate mbufs to store ip6 header and MLD header.
  404          * We allocate 2 mbufs and make chain in advance because
  405          * it is more convenient when inserting the hop-by-hop option later.
  406          */
  407         MGETHDR(mh, M_DONTWAIT, MT_HEADER);
  408         if (mh == NULL)
  409                 return;
  410         MGET(md, M_DONTWAIT, MT_DATA);
  411         if (md == NULL) {
  412                 m_free(mh);
  413                 return;
  414         }
  415         mh->m_next = md;
  416 
  417         mh->m_pkthdr.rcvif = NULL;
  418         mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
  419         mh->m_len = sizeof(struct ip6_hdr);
  420         MH_ALIGN(mh, sizeof(struct ip6_hdr));
  421 
  422         /* fill in the ip6 header */
  423         ip6 = mtod(mh, struct ip6_hdr *);
  424         ip6->ip6_flow = 0;
  425         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
  426         ip6->ip6_vfc |= IPV6_VERSION;
  427         /* ip6_plen will be set later */
  428         ip6->ip6_nxt = IPPROTO_ICMPV6;
  429         /* ip6_hlim will be set by im6o.im6o_multicast_hlim */
  430         ip6->ip6_src = ia->ia_addr.sin6_addr;
  431         ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
  432 
  433         /* fill in the MLD header */
  434         md->m_len = sizeof(struct mld_hdr);
  435         mldh = mtod(md, struct mld_hdr *);
  436         mldh->mld_type = type;
  437         mldh->mld_code = 0;
  438         mldh->mld_cksum = 0;
  439         /* XXX: we assume the function will not be called for query messages */
  440         mldh->mld_maxdelay = 0;
  441         mldh->mld_reserved = 0;
  442         mldh->mld_addr = in6m->in6m_addr;
  443         if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
  444                 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
  445         mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
  446                                     sizeof(struct mld_hdr));
  447 
  448         /* construct multicast option */
  449         bzero(&im6o, sizeof(im6o));
  450         im6o.im6o_multicast_ifp = ifp;
  451         im6o.im6o_multicast_hlim = 1;
  452 
  453         /*
  454          * Request loopback of the report if we are acting as a multicast
  455          * router, so that the process-level routing daemon can hear it.
  456          */
  457         im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
  458 
  459         /* increment output statictics */
  460         icmp6stat.icp6s_outhist[type]++;
  461 
  462         ip6_output(mh, &ip6_opts, NULL, 0, &im6o, &outif, NULL);
  463         if (outif) {
  464                 icmp6_ifstat_inc(outif, ifs6_out_msg);
  465                 switch (type) {
  466                 case MLD_LISTENER_QUERY:
  467                         icmp6_ifstat_inc(outif, ifs6_out_mldquery);
  468                         break;
  469                 case MLD_LISTENER_REPORT:
  470                         icmp6_ifstat_inc(outif, ifs6_out_mldreport);
  471                         break;
  472                 case MLD_LISTENER_DONE:
  473                         icmp6_ifstat_inc(outif, ifs6_out_mlddone);
  474                         break;
  475                 }
  476         }
  477 }

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