sys/netinet/igmp.c

   1 /*
   2  * Copyright (c) 1988 Stephen Deering.
   3  * Copyright (c) 1992, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * Stephen Deering of Stanford University.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
  34  * $FreeBSD: src/sys/netinet/igmp.c,v 1.29.2.2 2003/01/23 21:06:44 sam Exp $
  35  */
  36
  37 /*
  38  * Internet Group Management Protocol (IGMP) routines.
  39  *
  40  * Written by Steve Deering, Stanford, May 1988.
  41  * Modified by Rosen Sharma, Stanford, Aug 1994.
  42  * Modified by Bill Fenner, Xerox PARC, Feb 1995.
  43  * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995.
  44  *
  45  * MULTICAST Revision: 3.5.1.4
  46  */
  47
  48 #include <sys/param.h>
  49 #include <sys/systm.h>
  50 #include <sys/malloc.h>
  51 #include <sys/mbuf.h>
  52 #include <sys/socket.h>
  53 #include <sys/protosw.h>
  54 #include <sys/kernel.h>
  55 #include <sys/sysctl.h>
  56 #include <sys/in_cksum.h>
  57 #include <sys/thread2.h>
  58
  59 #include <machine/stdarg.h>
  60
  61 #include <net/if.h>
  62 #include <net/route.h>
  63 #include <net/netmsg2.h>
  64 #include <net/netisr2.h>
  65
  66 #include <netinet/in.h>
  67 #include <netinet/in_var.h>
  68 #include <netinet/in_systm.h>
  69 #include <netinet/ip.h>
  70 #include <netinet/ip_var.h>
  71 #include <netinet/igmp.h>
  72 #include <netinet/igmp_var.h>
  73
  74 #define IGMP_FASTTIMO           (hz / PR_FASTHZ)
  75 #define IGMP_SLOWTIMO           (hz / PR_SLOWHZ)
  76
  77 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
  78
  79 static struct router_info *
  80                 find_rti (struct ifnet *ifp);
  81
  82 static struct igmpstat igmpstat;
  83
  84 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW,
  85         &igmpstat, igmpstat, "IGMP statistics");
  86
  87 static int igmp_timers_are_running;
  88 static u_long igmp_all_hosts_group;
  89 static u_long igmp_all_rtrs_group;
  90 static struct mbuf *router_alert;
  91 static struct router_info *Head;
  92
  93 static void igmp_sendpkt (struct in_multi *, int, unsigned long);
  94 static void igmp_fasttimo_dispatch(netmsg_t);
  95 static void igmp_fasttimo(void *);
  96 static void igmp_slowtimo_dispatch(netmsg_t);
  97 static void igmp_slowtimo(void *);
  98
  99 static struct netmsg_base igmp_slowtimo_netmsg;
 100 static struct callout igmp_slowtimo_ch;
 101 static struct netmsg_base igmp_fasttimo_netmsg;
 102 static struct callout igmp_fasttimo_ch;
 103
 104 void
 105 igmp_init(void)
 106 {
 107         struct ipoption *ra;
 108
 109         /*
 110          * To avoid byte-swapping the same value over and over again.
 111          */
 112         igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
 113         igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
 114
 115         igmp_timers_are_running = 0;
 116
 117         /*
 118          * Construct a Router Alert option to use in outgoing packets
 119          */
 120         MGET(router_alert, M_NOWAIT, MT_DATA);
 121         ra = mtod(router_alert, struct ipoption *);
 122         ra->ipopt_dst.s_addr = 0;
 123         ra->ipopt_list[0] = IPOPT_RA;   /* Router Alert Option */
 124         ra->ipopt_list[1] = 0x04;       /* 4 bytes long */
 125         ra->ipopt_list[2] = 0x00;
 126         ra->ipopt_list[3] = 0x00;
 127         router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
 128
 129         Head = NULL;
 130
 131         callout_init_mp(&igmp_slowtimo_ch);
 132         netmsg_init(&igmp_slowtimo_netmsg, NULL, &netisr_adone_rport,
 133             MSGF_PRIORITY, igmp_slowtimo_dispatch);
 134
 135         callout_init_mp(&igmp_fasttimo_ch);
 136         netmsg_init(&igmp_fasttimo_netmsg, NULL, &netisr_adone_rport,
 137             MSGF_PRIORITY, igmp_fasttimo_dispatch);
 138
 139         callout_reset_bycpu(&igmp_slowtimo_ch, IGMP_SLOWTIMO,
 140             igmp_slowtimo, NULL, 0);
 141         callout_reset_bycpu(&igmp_fasttimo_ch, IGMP_FASTTIMO,
 142             igmp_fasttimo, NULL, 0);
 143 }
 144
 145 static struct router_info *
 146 find_rti(struct ifnet *ifp)
 147 {
 148         struct router_info *rti = Head;
 149
 150 #ifdef IGMP_DEBUG
 151         kprintf("[igmp.c, _find_rti] --> entering \n");
 152 #endif
 153         while (rti) {
 154                 if (rti->rti_ifp == ifp) {
 155 #ifdef IGMP_DEBUG
 156                         kprintf("[igmp.c, _find_rti] --> found old entry \n");
 157 #endif
 158                         return rti;
 159                 }
 160                 rti = rti->rti_next;
 161         }
 162         rti = kmalloc(sizeof *rti, M_IGMP, M_INTWAIT);
 163         rti->rti_ifp = ifp;
 164         rti->rti_type = IGMP_V2_ROUTER;
 165         rti->rti_time = 0;
 166         rti->rti_next = Head;
 167         Head = rti;
 168 #ifdef IGMP_DEBUG
 169         kprintf("[igmp.c, _find_rti] --> created an entry \n");
 170 #endif
 171         return rti;
 172 }
 173
 174 int
 175 igmp_input(struct mbuf **mp, int *offp, int proto)
 176 {
 177         struct mbuf *m = *mp;
 178         int iphlen;
 179         struct igmp *igmp;
 180         struct ip *ip;
 181         int igmplen;
 182         struct ifnet *ifp = m->m_pkthdr.rcvif;
 183         int minlen;
 184         struct in_multi *inm;
 185         struct in_ifaddr *ia;
 186         struct in_multistep step;
 187         struct router_info *rti;
 188         int timer; /** timer value in the igmp query header **/
 189
 190         iphlen = *offp;
 191         *mp = NULL;
 192
 193         ++igmpstat.igps_rcv_total;
 194
 195         ip = mtod(m, struct ip *);
 196         igmplen = ntohs(ip->ip_len) - iphlen;
 197
 198         /*
 199          * Validate lengths
 200          */
 201         if (igmplen < IGMP_MINLEN) {
 202                 ++igmpstat.igps_rcv_tooshort;
 203                 m_freem(m);
 204                 return(IPPROTO_DONE);
 205         }
 206         minlen = iphlen + IGMP_MINLEN;
 207         if ((m->m_flags & M_EXT || m->m_len < minlen) &&
 208             (m = m_pullup(m, minlen)) == NULL) {
 209                 ++igmpstat.igps_rcv_tooshort;
 210                 return(IPPROTO_DONE);
 211         }
 212
 213         /*
 214          * Validate checksum
 215          */
 216         m->m_data += iphlen;
 217         m->m_len -= iphlen;
 218         igmp = mtod(m, struct igmp *);
 219         if (in_cksum(m, igmplen)) {
 220                 ++igmpstat.igps_rcv_badsum;
 221                 m_freem(m);
 222                 return(IPPROTO_DONE);
 223         }
 224         m->m_data -= iphlen;
 225         m->m_len += iphlen;
 226
 227         ip = mtod(m, struct ip *);
 228         timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
 229         if (timer == 0)
 230                 timer = 1;
 231         rti = find_rti(ifp);
 232
 233         /*
 234          * In the IGMPv2 specification, there are 3 states and a flag.
 235          *
 236          * In Non-Member state, we simply don't have a membership record.
 237          * In Delaying Member state, our timer is running (inm->inm_timer)
 238          * In Idle Member state, our timer is not running (inm->inm_timer==0)
 239          *
 240          * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
 241          * we have heard a report from another member, or IGMP_IREPORTEDLAST
 242          * if I sent the last report.
 243          */
 244         switch (igmp->igmp_type) {
 245
 246         case IGMP_MEMBERSHIP_QUERY:
 247                 ++igmpstat.igps_rcv_queries;
 248
 249                 if (ifp->if_flags & IFF_LOOPBACK)
 250                         break;
 251
 252                 if (igmp->igmp_code == 0) {
 253                         /*
 254                          * Old router.  Remember that the querier on this
 255                          * interface is old, and set the timer to the
 256                          * value in RFC 1112.
 257                          */
 258
 259                         rti->rti_type = IGMP_V1_ROUTER;
 260                         rti->rti_time = 0;
 261
 262                         timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
 263
 264                         if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
 265                             igmp->igmp_group.s_addr != 0) {
 266                                 ++igmpstat.igps_rcv_badqueries;
 267                                 m_freem(m);
 268                                 return(IPPROTO_DONE);
 269                         }
 270                 } else {
 271                         /*
 272                          * New router.  Simply do the new validity check.
 273                          */
 274
 275                         if (igmp->igmp_group.s_addr != 0 &&
 276                             !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
 277                                 ++igmpstat.igps_rcv_badqueries;
 278                                 m_freem(m);
 279                                 return(IPPROTO_DONE);
 280                         }
 281                 }
 282
 283                 /*
 284                  * - Start the timers in all of our membership records
 285                  *   that the query applies to for the interface on
 286                  *   which the query arrived excl. those that belong
 287                  *   to the "all-hosts" group (224.0.0.1).
 288                  * - Restart any timer that is already running but has
 289                  *   a value longer than the requested timeout.
 290                  * - Use the value specified in the query message as
 291                  *   the maximum timeout.
 292                  */
 293                 IN_FIRST_MULTI(step, inm);
 294                 while (inm != NULL) {
 295                         if (inm->inm_ifp == ifp &&
 296                             inm->inm_addr.s_addr != igmp_all_hosts_group &&
 297                             (igmp->igmp_group.s_addr == 0 ||
 298                              igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
 299                                 if (inm->inm_timer == 0 ||
 300                                     inm->inm_timer > timer) {
 301                                         inm->inm_timer =
 302                                                 IGMP_RANDOM_DELAY(timer);
 303                                         igmp_timers_are_running = 1;
 304                                 }
 305                         }
 306                         IN_NEXT_MULTI(step, inm);
 307                 }
 308
 309                 break;
 310
 311         case IGMP_V1_MEMBERSHIP_REPORT:
 312         case IGMP_V2_MEMBERSHIP_REPORT:
 313                 /*
 314                  * For fast leave to work, we have to know that we are the
 315                  * last person to send a report for this group.  Reports
 316                  * can potentially get looped back if we are a multicast
 317                  * router, so discard reports sourced by me.
 318                  */
 319                 ia = IFP_TO_IA(ifp);
 320                 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
 321                         break;
 322
 323                 ++igmpstat.igps_rcv_reports;
 324
 325                 if (ifp->if_flags & IFF_LOOPBACK)
 326                         break;
 327
 328                 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
 329                         ++igmpstat.igps_rcv_badreports;
 330                         m_freem(m);
 331                         return(IPPROTO_DONE);
 332                 }
 333
 334                 /*
 335                  * KLUDGE: if the IP source address of the report has an
 336                  * unspecified (i.e., zero) subnet number, as is allowed for
 337                  * a booting host, replace it with the correct subnet number
 338                  * so that a process-level multicast routing demon can
 339                  * determine which subnet it arrived from.  This is necessary
 340                  * to compensate for the lack of any way for a process to
 341                  * determine the arrival interface of an incoming packet.
 342                  */
 343                 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
 344                         if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
 345
 346                 /*
 347                  * If we belong to the group being reported, stop
 348                  * our timer for that group.
 349                  */
 350                 inm = IN_LOOKUP_MULTI(&igmp->igmp_group, ifp);
 351
 352                 if (inm != NULL) {
 353                         inm->inm_timer = 0;
 354                         ++igmpstat.igps_rcv_ourreports;
 355
 356                         inm->inm_state = IGMP_OTHERMEMBER;
 357                 }
 358
 359                 break;
 360         }
 361
 362         /*
 363          * Pass all valid IGMP packets up to any process(es) listening
 364          * on a raw IGMP socket.
 365          */
 366         *mp = m;
 367         rip_input(mp, offp, proto);
 368         return(IPPROTO_DONE);
 369 }
 370
 371 void
 372 igmp_joingroup(struct in_multi *inm)
 373 {
 374         crit_enter();
 375         if (inm->inm_addr.s_addr == igmp_all_hosts_group
 376             || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
 377                 inm->inm_timer = 0;
 378                 inm->inm_state = IGMP_OTHERMEMBER;
 379         } else {
 380                 inm->inm_rti = find_rti(inm->inm_ifp);
 381                 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
 382                 inm->inm_timer = IGMP_RANDOM_DELAY(
 383                                         IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
 384                 inm->inm_state = IGMP_IREPORTEDLAST;
 385                 igmp_timers_are_running = 1;
 386         }
 387         crit_exit();
 388 }
 389
 390 void
 391 igmp_leavegroup(struct in_multi *inm)
 392 {
 393         if (inm->inm_state == IGMP_IREPORTEDLAST &&
 394             inm->inm_addr.s_addr != igmp_all_hosts_group &&
 395             !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
 396             inm->inm_rti->rti_type != IGMP_V1_ROUTER)
 397                 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
 398 }
 399
 400 static void
 401 igmp_fasttimo(void *dummy __unused)
 402 {
 403         struct netmsg_base *msg = &igmp_fasttimo_netmsg;
 404
 405         KKASSERT(mycpuid == 0);
 406
 407         crit_enter();
 408         if (msg->lmsg.ms_flags & MSGF_DONE)
 409                 netisr_sendmsg_oncpu(msg);
 410         crit_exit();
 411 }
 412
 413 static void
 414 igmp_fasttimo_dispatch(netmsg_t nmsg)
 415 {
 416         struct in_multi *inm;
 417         struct in_multistep step;
 418
 419         ASSERT_NETISR0;
 420
 421         crit_enter();
 422         netisr_replymsg(&nmsg->base, 0);        /* reply ASAP */
 423         crit_exit();
 424
 425         /*
 426          * Quick check to see if any work needs to be done, in order
 427          * to minimize the overhead of fasttimo processing.
 428          */
 429
 430         if (!igmp_timers_are_running)
 431                 goto done;
 432
 433         igmp_timers_are_running = 0;
 434         IN_FIRST_MULTI(step, inm);
 435         while (inm != NULL) {
 436                 if (inm->inm_timer == 0) {
 437                         /* do nothing */
 438                 } else if (--inm->inm_timer == 0) {
 439                         igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
 440                         inm->inm_state = IGMP_IREPORTEDLAST;
 441                 } else {
 442                         igmp_timers_are_running = 1;
 443                 }
 444                 IN_NEXT_MULTI(step, inm);
 445         }
 446 done:
 447         callout_reset(&igmp_fasttimo_ch, IGMP_FASTTIMO, igmp_fasttimo, NULL);
 448 }
 449
 450 static void
 451 igmp_slowtimo(void *dummy __unused)
 452 {
 453         struct netmsg_base *msg = &igmp_slowtimo_netmsg;
 454
 455         KKASSERT(mycpuid == 0);
 456
 457         crit_enter();
 458         if (msg->lmsg.ms_flags & MSGF_DONE)
 459                 netisr_sendmsg_oncpu(msg);
 460         crit_exit();
 461 }
 462
 463 static void
 464 igmp_slowtimo_dispatch(netmsg_t nmsg)
 465 {
 466         struct router_info *rti = Head;
 467
 468         ASSERT_NETISR0;
 469
 470         crit_enter();
 471         netisr_replymsg(&nmsg->base, 0);        /* reply ASAP */
 472         crit_exit();
 473
 474 #ifdef IGMP_DEBUG
 475         kprintf("[igmp.c,_slowtimo] -- > entering \n");
 476 #endif
 477         while (rti) {
 478             if (rti->rti_type == IGMP_V1_ROUTER) {
 479                 rti->rti_time++;
 480                 if (rti->rti_time >= IGMP_AGE_THRESHOLD) {
 481                         rti->rti_type = IGMP_V2_ROUTER;
 482                 }
 483             }
 484             rti = rti->rti_next;
 485         }
 486 #ifdef IGMP_DEBUG
 487         kprintf("[igmp.c,_slowtimo] -- > exiting \n");
 488 #endif
 489         callout_reset(&igmp_slowtimo_ch, IGMP_SLOWTIMO, igmp_slowtimo, NULL);
 490 }
 491
 492 static struct route igmprt;
 493
 494 static void
 495 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr)
 496 {
 497         struct mbuf *m;
 498         struct igmp *igmp;
 499         struct ip *ip;
 500         struct ip_moptions imo;
 501
 502         MGETHDR(m, M_NOWAIT, MT_HEADER);
 503         if (m == NULL)
 504                 return;
 505
 506         m->m_pkthdr.rcvif = loif;
 507         m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
 508         MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
 509         m->m_data += sizeof(struct ip);
 510         m->m_len = IGMP_MINLEN;
 511         igmp = mtod(m, struct igmp *);
 512         igmp->igmp_type   = type;
 513         igmp->igmp_code   = 0;
 514         igmp->igmp_group  = inm->inm_addr;
 515         igmp->igmp_cksum  = 0;
 516         igmp->igmp_cksum  = in_cksum(m, IGMP_MINLEN);
 517
 518         m->m_data -= sizeof(struct ip);
 519         m->m_len += sizeof(struct ip);
 520         ip = mtod(m, struct ip *);
 521         ip->ip_tos = 0;
 522         ip->ip_len = htons(sizeof(struct ip) + IGMP_MINLEN);
 523         ip->ip_off = 0;
 524         ip->ip_p = IPPROTO_IGMP;
 525         ip->ip_src.s_addr = INADDR_ANY;
 526         ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
 527
 528         imo.imo_multicast_ifp = inm->inm_ifp;
 529         imo.imo_multicast_ttl = 1;
 530         imo.imo_multicast_vif = -1;
 531         /*
 532          * Request loopback of the report if we are acting as a multicast
 533          * router, so that the process-level routing demon can hear it.
 534          */
 535         imo.imo_multicast_loop = (ip_mrouter != NULL);
 536
 537         /*
 538          * XXX
 539          * Do we have to worry about reentrancy here?  Don't think so.
 540          */
 541         ip_output(m, router_alert, &igmprt, 0, &imo, NULL);
 542
 543         ++igmpstat.igps_snd_reports;
 544 }