sys/netinet6/mld6.c

   1 /*      $FreeBSD: src/sys/netinet6/mld6.c,v 1.4.2.4 2003/01/23 21:06:47 sam Exp $       */
   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. Neither the name of the University nor the names of its contributors
  50  *    may be used to endorse or promote products derived from this software
  51  *    without specific prior written permission.
  52  *
  53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  63  * SUCH DAMAGE.
  64  *
  65  *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
  66  */
  67
  68 #include "opt_inet.h"
  69 #include "opt_inet6.h"
  70
  71 #include <sys/param.h>
  72 #include <sys/systm.h>
  73 #include <sys/mbuf.h>
  74 #include <sys/socket.h>
  75 #include <sys/protosw.h>
  76 #include <sys/syslog.h>
  77 #include <sys/thread2.h>
  78
  79 #include <net/if.h>
  80
  81 #include <netinet/in.h>
  82 #include <netinet/in_var.h>
  83 #include <netinet/ip6.h>
  84 #include <netinet6/ip6_var.h>
  85 #include <netinet/icmp6.h>
  86 #include <netinet6/mld6_var.h>
  87
  88 #include <net/net_osdep.h>
  89
  90 /*
  91  * Protocol constants
  92  */
  93
  94 /* denotes that the MLD max response delay field specifies time in milliseconds */
  95 #define MLD6_TIMER_SCALE        1000
  96 /*
  97  * time between repetitions of a node's initial report of interest in a
  98  * multicast address(in seconds)
  99  */
 100 #define MLD6_UNSOLICITED_REPORT_INTERVAL        10
 101
 102 static struct ip6_pktopts ip6_opts;
 103 static int mld6_timers_are_running;
 104 /* XXX: These are necessary for KAME's link-local hack */
 105 static struct in6_addr mld6_all_nodes_linklocal = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
 106 static struct in6_addr mld6_all_routers_linklocal = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
 107
 108 static void mld6_sendpkt(struct in6_multi *, int, const struct in6_addr *);
 109
 110 static struct lwkt_token mld6_token = LWKT_TOKEN_INITIALIZER(mp_token);
 111
 112
 113 void
 114 mld6_init(void)
 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_RTALERT;
 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(struct in6_multi *in6m)
 138 {
 139         /*
 140          * RFC2710 page 10:
 141          * The node never sends a Report or Done for the link-scope all-nodes
 142          * address.
 143          * MLD messages are never sent for multicast addresses whose scope is 0
 144          * (reserved) or 1 (node-local).
 145          */
 146         lwkt_gettoken(&mld6_token);
 147         mld6_all_nodes_linklocal.s6_addr16[1] =
 148                 htons(in6m->in6m_ifp->if_index); /* XXX */
 149         if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal) ||
 150             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) < IPV6_ADDR_SCOPE_LINKLOCAL) {
 151                 in6m->in6m_timer = 0;
 152                 in6m->in6m_state = MLD6_OTHERLISTENER;
 153         } else {
 154                 mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
 155                 in6m->in6m_timer = MLD6_RANDOM_DELAY(
 156                         MLD6_UNSOLICITED_REPORT_INTERVAL * PR_FASTHZ);
 157                 in6m->in6m_state = MLD6_IREPORTEDLAST;
 158                 mld6_timers_are_running = 1;
 159         }
 160         lwkt_reltoken(&mld6_token);
 161 }
 162
 163 void
 164 mld6_stop_listening(struct in6_multi *in6m)
 165 {
 166         mld6_all_nodes_linklocal.s6_addr16[1] =
 167                 htons(in6m->in6m_ifp->if_index); /* XXX */
 168         mld6_all_routers_linklocal.s6_addr16[1] =
 169                 htons(in6m->in6m_ifp->if_index); /* XXX: necessary when mrouting */
 170
 171         if (in6m->in6m_state == MLD6_IREPORTEDLAST &&
 172             (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal)) &&
 173             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) > IPV6_ADDR_SCOPE_INTFACELOCAL)
 174                 mld6_sendpkt(in6m, MLD_LISTENER_DONE,
 175                              &mld6_all_routers_linklocal);
 176 }
 177
 178 void
 179 mld6_input(struct mbuf *m, int off)
 180 {
 181         struct ip6_hdr *ip6;
 182         struct mld_hdr *mldh;
 183         struct ifnet *ifp = m->m_pkthdr.rcvif;
 184         struct in6_multi *in6m;
 185         struct in6_ifaddr *ia;
 186         struct ifmultiaddr *ifma, mark;
 187         struct sockaddr sa;
 188         int timer;              /* timer value in the MLD query header */
 189
 190 #ifndef PULLDOWN_TEST
 191         IP6_EXTHDR_CHECK(m, off, sizeof(*mldh),);
 192         mldh = (struct mld_hdr *)(mtod(m, caddr_t) + off);
 193 #else
 194         IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
 195         if (mldh == NULL) {
 196                 icmp6stat.icp6s_tooshort++;
 197                 return;
 198         }
 199 #endif
 200
 201         lwkt_gettoken(&mld6_token);
 202         /* source address validation */
 203         ip6 = mtod(m, struct ip6_hdr *); /* in case mpullup */
 204         if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
 205 #if 0
 206                 log(LOG_ERR,
 207                     "mld6_input: src %s is not link-local (grp=%s)\n",
 208                     ip6_sprintf(&ip6->ip6_src),
 209                     ip6_sprintf(&mldh->mld_addr));
 210 #endif
 211                 /*
 212                  * spec (RFC2710) does not explicitly
 213                  * specify to discard the packet from a non link-local
 214                  * source address. But we believe it's expected to do so.
 215                  * XXX: do we have to allow :: as source?
 216                  */
 217                 m_freem(m);
 218                 lwkt_reltoken(&mld6_token);
 219                 return;
 220         }
 221
 222         /*
 223          * In the MLD6 specification, there are 3 states and a flag.
 224          *
 225          * In Non-Listener state, we simply don't have a membership record.
 226          * In Delaying Listener state, our timer is running (in6m->in6m_timer)
 227          * In Idle Listener state, our timer is not running (in6m->in6m_timer==0)
 228          *
 229          * The flag is in6m->in6m_state, it is set to MLD6_OTHERLISTENER if
 230          * we have heard a report from another member, or MLD6_IREPORTEDLAST
 231          * if we sent the last report.
 232          */
 233         switch(mldh->mld_type) {
 234         case MLD_LISTENER_QUERY:
 235                 if (ifp->if_flags & IFF_LOOPBACK)
 236                         break;
 237
 238                 if (!IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) &&
 239                     !IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
 240                         break;  /* print error or log stat? */
 241                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
 242                         mldh->mld_addr.s6_addr16[1] =
 243                                 htons(ifp->if_index); /* XXX */
 244
 245                 /*
 246                  * - Start the timers in all of our membership records
 247                  *   that the query applies to for the interface on
 248                  *   which the query arrived excl. those that belong
 249                  *   to the "all-nodes" group (ff02::1).
 250                  * - Restart any timer that is already running but has
 251                  *   A value longer than the requested timeout.
 252                  * - Use the value specified in the query message as
 253                  *   the maximum timeout.
 254                  */
 255                 IFP_TO_IA6(ifp, ia);
 256                 if (ia == NULL)
 257                         break;
 258
 259                 /*
 260                  * XXX: System timer resolution is too low to handle Max
 261                  * Response Delay, so set 1 to the internal timer even if
 262                  * the calculated value equals to zero when Max Response
 263                  * Delay is positive.
 264                  */
 265                 timer = ntohs(mldh->mld_maxdelay) * PR_FASTHZ /
 266                     MLD6_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                 bzero(&sa, sizeof(sa));
 273                 sa.sa_family = AF_UNSPEC;
 274                 sa.sa_len = sizeof(sa);
 275
 276                 bzero(&mark, sizeof(mark));
 277                 mark.ifma_addr = &sa;
 278
 279                 /* TODO: need ifnet_serialize_main */
 280                 ifnet_serialize_all(ifp);
 281
 282                 TAILQ_INSERT_HEAD(&ifp->if_multiaddrs, &mark, ifma_link);
 283                 while ((ifma = TAILQ_NEXT(&mark, ifma_link)) != NULL) {
 284                         TAILQ_REMOVE(&ifp->if_multiaddrs, &mark, ifma_link);
 285                         TAILQ_INSERT_AFTER(&ifp->if_multiaddrs, ifma, &mark,
 286                             ifma_link);
 287
 288                         if (ifma->ifma_addr->sa_family != AF_INET6)
 289                                 continue;
 290                         in6m = (struct in6_multi *)ifma->ifma_protospec;
 291
 292                         if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr,
 293                                         &mld6_all_nodes_linklocal) ||
 294                             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
 295                             IPV6_ADDR_SCOPE_LINKLOCAL)
 296                                 continue;
 297
 298                         if (IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) ||
 299                             IN6_ARE_ADDR_EQUAL(&mldh->mld_addr,
 300                                                 &in6m->in6m_addr))
 301                         {
 302                                 if (timer == 0) {
 303                                         /*
 304                                          * Release serializer(s) temporarily,
 305                                          * before sending report.
 306                                          */
 307                                         ifnet_deserialize_all(ifp);
 308                                         /* send a report immediately */
 309                                         mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
 310                                                 NULL);
 311                                         ifnet_serialize_all(ifp);
 312                                         in6m->in6m_timer = 0; /* reset timer */
 313                                         in6m->in6m_state = MLD6_IREPORTEDLAST;
 314                                 }
 315                                 else if (in6m->in6m_timer == 0 || /*idle state*/
 316                                         in6m->in6m_timer > timer) {
 317                                         in6m->in6m_timer =
 318                                                 MLD6_RANDOM_DELAY(timer);
 319                                         mld6_timers_are_running = 1;
 320                                 }
 321                         }
 322                 }
 323                 TAILQ_REMOVE(&ifp->if_multiaddrs, &mark, ifma_link);
 324
 325                 ifnet_deserialize_all(ifp);
 326
 327                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
 328                         mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
 329                 break;
 330
 331         case MLD_LISTENER_REPORT:
 332                 /*
 333                  * For fast leave to work, we have to know that we are the
 334                  * last person to send a report for this group.  Reports
 335                  * can potentially get looped back if we are a multicast
 336                  * router, so discard reports sourced by me.
 337                  * Note that it is impossible to check IFF_LOOPBACK flag of
 338                  * ifp for this purpose, since ip6_mloopback pass the physical
 339                  * interface to looutput.
 340                  */
 341                 if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
 342                         break;
 343
 344                 if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
 345                         break;
 346
 347                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
 348                         mldh->mld_addr.s6_addr16[1] =
 349                                 htons(ifp->if_index); /* XXX */
 350                 /*
 351                  * If we belong to the group being reported, stop
 352                  * our timer for that group.
 353                  */
 354                 in6m = IN6_LOOKUP_MULTI(&mldh->mld_addr, ifp);
 355                 if (in6m) {
 356                         in6m->in6m_timer = 0; /* transit to idle state */
 357                         in6m->in6m_state = MLD6_OTHERLISTENER; /* clear flag */
 358                 }
 359
 360                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
 361                         mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
 362                 break;
 363         default:                /* this is impossible */
 364                 log(LOG_ERR, "mld6_input: illegal type(%d)", mldh->mld_type);
 365                 break;
 366         }
 367
 368         m_freem(m);
 369         lwkt_reltoken(&mld6_token);
 370 }
 371
 372 void
 373 mld6_fasttimeo(void)
 374 {
 375         struct in6_multi *in6m;
 376         struct in6_multistep step;
 377
 378         /*
 379          * Quick check to see if any work needs to be done, in order
 380          * to minimize the overhead of fasttimo processing.
 381          */
 382         lwkt_gettoken(&mld6_token);
 383
 384         if (!mld6_timers_are_running) {
 385                 lwkt_reltoken(&mld6_token);
 386                 return;
 387         }
 388
 389         mld6_timers_are_running = 0;
 390         IN6_FIRST_MULTI(step, in6m);
 391         while (in6m != NULL) {
 392                 if (in6m->in6m_timer == 0) {
 393                         /* do nothing */
 394                 } else if (--in6m->in6m_timer == 0) {
 395                         mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
 396                         in6m->in6m_state = MLD6_IREPORTEDLAST;
 397                 } else {
 398                         mld6_timers_are_running = 1;
 399                 }
 400                 IN6_NEXT_MULTI(step, in6m);
 401         }
 402
 403         lwkt_reltoken(&mld6_token);
 404 }
 405
 406 static void
 407 mld6_sendpkt(struct in6_multi *in6m, int type, const struct in6_addr *dst)
 408 {
 409         struct mbuf *mh, *md;
 410         struct mld_hdr *mldh;
 411         struct ip6_hdr *ip6;
 412         struct ip6_moptions im6o;
 413         struct in6_ifaddr *ia;
 414         struct ifnet *ifp = in6m->in6m_ifp;
 415         struct ifnet *outif = NULL;
 416
 417         /*
 418          * At first, find a link local address on the outgoing interface
 419          * to use as the source address of the MLD packet.
 420          */
 421         if ((ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST))
 422             == NULL)
 423                 return;
 424
 425         /*
 426          * Allocate mbufs to store ip6 header and MLD header.
 427          * We allocate 2 mbufs and make chain in advance because
 428          * it is more convenient when inserting the hop-by-hop option later.
 429          */
 430         MGETHDR(mh, M_NOWAIT, MT_HEADER);
 431         if (mh == NULL)
 432                 return;
 433         MGET(md, M_NOWAIT, MT_DATA);
 434         if (md == NULL) {
 435                 m_free(mh);
 436                 return;
 437         }
 438         mh->m_next = md;
 439
 440         mh->m_pkthdr.rcvif = NULL;
 441         mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
 442         mh->m_len = sizeof(struct ip6_hdr);
 443         MH_ALIGN(mh, sizeof(struct ip6_hdr));
 444
 445         /* fill in the ip6 header */
 446         ip6 = mtod(mh, struct ip6_hdr *);
 447         ip6->ip6_flow = 0;
 448         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
 449         ip6->ip6_vfc |= IPV6_VERSION;
 450         /* ip6_plen will be set later */
 451         ip6->ip6_nxt = IPPROTO_ICMPV6;
 452         /* ip6_hlim will be set by im6o.im6o_multicast_hlim */
 453         ip6->ip6_src = ia->ia_addr.sin6_addr;
 454         ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
 455
 456         /* fill in the MLD header */
 457         md->m_len = sizeof(struct mld_hdr);
 458         mldh = mtod(md, struct mld_hdr *);
 459         mldh->mld_type = type;
 460         mldh->mld_code = 0;
 461         mldh->mld_cksum = 0;
 462         /* XXX: we assume the function will not be called for query messages */
 463         mldh->mld_maxdelay = 0;
 464         mldh->mld_reserved = 0;
 465         mldh->mld_addr = in6m->in6m_addr;
 466         if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
 467                 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
 468         mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
 469             sizeof(struct mld_hdr));
 470
 471         /* construct multicast option */
 472         bzero(&im6o, sizeof(im6o));
 473         im6o.im6o_multicast_ifp = ifp;
 474         im6o.im6o_multicast_hlim = 1;
 475
 476         /*
 477          * Request loopback of the report if we are acting as a multicast
 478          * router, so that the process-level routing daemon can hear it.
 479          */
 480         im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
 481
 482         /* increment output statictics */
 483         icmp6stat.icp6s_outhist[type]++;
 484
 485         ip6_output(mh, &ip6_opts, NULL, 0, &im6o, &outif, NULL);
 486         if (outif) {
 487                 icmp6_ifstat_inc(outif, ifs6_out_msg);
 488                 switch (type) {
 489                 case MLD_LISTENER_QUERY:
 490                         icmp6_ifstat_inc(outif, ifs6_out_mldquery);
 491                         break;
 492                 case MLD_LISTENER_REPORT:
 493                         icmp6_ifstat_inc(outif, ifs6_out_mldreport);
 494                         break;
 495                 case MLD_LISTENER_DONE:
 496                         icmp6_ifstat_inc(outif, ifs6_out_mlddone);
 497                         break;
 498                 }
 499         }
 500 }