bsd/netinet/igmp.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1988 Stephen Deering.
  24  * Copyright (c) 1992, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  *
  27  * This code is derived from software contributed to Berkeley by
  28  * Stephen Deering of Stanford University.
  29  *
  30  * Redistribution and use in source and binary forms, with or without
  31  * modification, are permitted provided that the following conditions
  32  * are met:
  33  * 1. Redistributions of source code must retain the above copyright
  34  *    notice, this list of conditions and the following disclaimer.
  35  * 2. Redistributions in binary form must reproduce the above copyright
  36  *    notice, this list of conditions and the following disclaimer in the
  37  *    documentation and/or other materials provided with the distribution.
  38  * 3. All advertising materials mentioning features or use of this software
  39  *    must display the following acknowledgement:
  40  *      This product includes software developed by the University of
  41  *      California, Berkeley and its contributors.
  42  * 4. Neither the name of the University nor the names of its contributors
  43  *    may be used to endorse or promote products derived from this software
  44  *    without specific prior written permission.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  *
  58  *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
  59  */
  60
  61 /*
  62  * Internet Group Management Protocol (IGMP) routines.
  63  *
  64  * Written by Steve Deering, Stanford, May 1988.
  65  * Modified by Rosen Sharma, Stanford, Aug 1994.
  66  * Modified by Bill Fenner, Xerox PARC, Feb 1995.
  67  * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995.
  68  *
  69  * MULTICAST Revision: 3.5.1.4
  70  */
  71
  72 #include <sys/param.h>
  73 #include <sys/systm.h>
  74 #include <sys/malloc.h>
  75 #include <sys/mbuf.h>
  76 #include <sys/socket.h>
  77 #include <sys/protosw.h>
  78 #include <sys/kernel.h>
  79 #include <sys/sysctl.h>
  80
  81 #include <net/if.h>
  82 #include <net/route.h>
  83
  84 #include <netinet/in.h>
  85 #include <netinet/in_var.h>
  86 #include <netinet/in_systm.h>
  87 #include <netinet/ip.h>
  88 #include <netinet/ip_var.h>
  89 #include <netinet/igmp.h>
  90 #include <netinet/igmp_var.h>
  91
  92 #ifndef __APPLE__
  93 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
  94 #endif
  95
  96 static struct router_info *
  97                 find_rti(struct ifnet *ifp);
  98
  99 static struct igmpstat igmpstat;
 100
 101 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD,
 102         &igmpstat, igmpstat, "");
 103
 104 static int igmp_timers_are_running;
 105 static u_long igmp_all_hosts_group;
 106 static u_long igmp_all_rtrs_group;
 107 static struct mbuf *router_alert;
 108 static struct router_info *Head;
 109
 110 static void igmp_sendpkt(struct in_multi *, int, unsigned long);
 111
 112 void
 113 igmp_init()
 114 {
 115         struct ipoption *ra;
 116
 117         /*
 118          * To avoid byte-swapping the same value over and over again.
 119          */
 120         igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
 121         igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
 122
 123         igmp_timers_are_running = 0;
 124
 125         /*
 126          * Construct a Router Alert option to use in outgoing packets
 127          */
 128         MGET(router_alert, M_DONTWAIT, MT_DATA);
 129         ra = mtod(router_alert, struct ipoption *);
 130         ra->ipopt_dst.s_addr = 0;
 131         ra->ipopt_list[0] = IPOPT_RA;   /* Router Alert Option */
 132         ra->ipopt_list[1] = 0x04;       /* 4 bytes long */
 133         ra->ipopt_list[2] = 0x00;
 134         ra->ipopt_list[3] = 0x00;
 135         router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
 136
 137         Head = (struct router_info *) 0;
 138 }
 139
 140 static struct router_info *
 141 find_rti(
 142         struct ifnet *ifp)
 143 {
 144         struct router_info *rti = Head;
 145
 146
 147 #if IGMP_DEBUG
 148         printf("[igmp.c, _find_rti] --> entering \n");
 149 #endif
 150         while (rti) {
 151                 if (rti->rti_ifp == ifp) {
 152 #if IGMP_DEBUG
 153                         printf("[igmp.c, _find_rti] --> found old entry \n");
 154 #endif
 155                         return rti;
 156                 }
 157                 rti = rti->rti_next;
 158         }
 159
 160         MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT);
 161         if (rti != NULL)
 162         {
 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         }
 169 #if IGMP_DEBUG
 170         if (rti) printf("[igmp.c, _find_rti] --> created an entry \n");
 171 #endif
 172         return rti;
 173 }
 174
 175 void
 176 igmp_input(
 177         struct mbuf *m,
 178         int iphlen)
 179 {
 180         struct igmp *igmp;
 181         struct ip *ip;
 182         int igmplen;
 183         struct ifnet *ifp = m->m_pkthdr.rcvif;
 184         int minlen;
 185         struct in_multi *inm;
 186         struct in_ifaddr *ia;
 187         struct in_multistep step;
 188         struct router_info *rti;
 189
 190         int timer; /** timer value in the igmp query header **/
 191
 192         ++igmpstat.igps_rcv_total;
 193
 194         ip = mtod(m, struct ip *);
 195         igmplen = ip->ip_len;
 196
 197         /*
 198          * Validate lengths
 199          */
 200         if (igmplen < IGMP_MINLEN) {
 201                 ++igmpstat.igps_rcv_tooshort;
 202                 m_freem(m);
 203                 return;
 204         }
 205         minlen = iphlen + IGMP_MINLEN;
 206         if ((m->m_flags & M_EXT || m->m_len < minlen) &&
 207             (m = m_pullup(m, minlen)) == 0) {
 208                 ++igmpstat.igps_rcv_tooshort;
 209                 return;
 210         }
 211
 212         /*
 213          * Validate checksum
 214          */
 215         m->m_data += iphlen;
 216         m->m_len -= iphlen;
 217         igmp = mtod(m, struct igmp *);
 218         if (in_cksum(m, igmplen)) {
 219                 ++igmpstat.igps_rcv_badsum;
 220                 m_freem(m);
 221                 return;
 222         }
 223         m->m_data -= iphlen;
 224         m->m_len += iphlen;
 225
 226         ip = mtod(m, struct ip *);
 227         timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
 228         if (timer == 0)
 229                 timer = 1;
 230         rti = find_rti(ifp);
 231         if (rti == NULL) {
 232                 m_freem(m);
 233                 return;
 234         }
 235
 236         /*
 237          * In the IGMPv2 specification, there are 3 states and a flag.
 238          *
 239          * In Non-Member state, we simply don't have a membership record.
 240          * In Delaying Member state, our timer is running (inm->inm_timer)
 241          * In Idle Member state, our timer is not running (inm->inm_timer==0)
 242          *
 243          * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
 244          * we have heard a report from another member, or IGMP_IREPORTEDLAST
 245          * if I sent the last report.
 246          */
 247         switch (igmp->igmp_type) {
 248
 249         case IGMP_MEMBERSHIP_QUERY:
 250                 ++igmpstat.igps_rcv_queries;
 251
 252                 if (ifp->if_flags & IFF_LOOPBACK)
 253                         break;
 254
 255                 if (igmp->igmp_code == 0) {
 256                         /*
 257                          * Old router.  Remember that the querier on this
 258                          * interface is old, and set the timer to the
 259                          * value in RFC 1112.
 260                          */
 261
 262                         rti->rti_type = IGMP_V1_ROUTER;
 263                         rti->rti_time = 0;
 264
 265                         timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
 266
 267                         if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
 268                             igmp->igmp_group.s_addr != 0) {
 269                                 ++igmpstat.igps_rcv_badqueries;
 270                                 m_freem(m);
 271                                 return;
 272                         }
 273                 } else {
 274                         /*
 275                          * New router.  Simply do the new validity check.
 276                          */
 277
 278                         if (igmp->igmp_group.s_addr != 0 &&
 279                             !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
 280                                 ++igmpstat.igps_rcv_badqueries;
 281                                 m_freem(m);
 282                                 return;
 283                         }
 284                 }
 285
 286                 /*
 287                  * - Start the timers in all of our membership records
 288                  *   that the query applies to for the interface on
 289                  *   which the query arrived excl. those that belong
 290                  *   to the "all-hosts" group (224.0.0.1).
 291                  * - Restart any timer that is already running but has
 292                  *   a value longer than the requested timeout.
 293                  * - Use the value specified in the query message as
 294                  *   the maximum timeout.
 295                  */
 296                 lck_mtx_lock(rt_mtx);
 297                 IN_FIRST_MULTI(step, inm);
 298                 while (inm != NULL) {
 299                         if (inm->inm_ifp == ifp &&
 300                             inm->inm_addr.s_addr != igmp_all_hosts_group &&
 301                             (igmp->igmp_group.s_addr == 0 ||
 302                              igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
 303                                 if (inm->inm_timer == 0 ||
 304                                     inm->inm_timer > timer) {
 305                                         inm->inm_timer =
 306                                                 IGMP_RANDOM_DELAY(timer);
 307                                         igmp_timers_are_running = 1;
 308                                 }
 309                         }
 310                         IN_NEXT_MULTI(step, inm);
 311                 }
 312                 lck_mtx_unlock(rt_mtx);
 313
 314                 break;
 315
 316         case IGMP_V1_MEMBERSHIP_REPORT:
 317         case IGMP_V2_MEMBERSHIP_REPORT:
 318                 /*
 319                  * For fast leave to work, we have to know that we are the
 320                  * last person to send a report for this group.  Reports
 321                  * can potentially get looped back if we are a multicast
 322                  * router, so discard reports sourced by me.
 323                  */
 324                 IFP_TO_IA(ifp, ia);
 325                 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
 326                         break;
 327
 328                 ++igmpstat.igps_rcv_reports;
 329
 330                 if (ifp->if_flags & IFF_LOOPBACK)
 331                         break;
 332
 333                 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
 334                         ++igmpstat.igps_rcv_badreports;
 335                         m_freem(m);
 336                         return;
 337                 }
 338
 339                 /*
 340                  * KLUDGE: if the IP source address of the report has an
 341                  * unspecified (i.e., zero) subnet number, as is allowed for
 342                  * a booting host, replace it with the correct subnet number
 343                  * so that a process-level multicast routing demon can
 344                  * determine which subnet it arrived from.  This is necessary
 345                  * to compensate for the lack of any way for a process to
 346                  * determine the arrival interface of an incoming packet.
 347                  */
 348                 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
 349                         if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
 350
 351                 /*
 352                  * If we belong to the group being reported, stop
 353                  * our timer for that group.
 354                  */
 355                 ifnet_lock_shared(ifp);
 356                 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
 357                 ifnet_lock_done(ifp);
 358
 359                 if (inm != NULL) {
 360                         inm->inm_timer = 0;
 361                         ++igmpstat.igps_rcv_ourreports;
 362
 363                         inm->inm_state = IGMP_OTHERMEMBER;
 364                 }
 365
 366                 break;
 367         }
 368
 369         /*
 370          * Pass all valid IGMP packets up to any process(es) listening
 371          * on a raw IGMP socket.
 372          */
 373         rip_input(m, iphlen);
 374 }
 375
 376 int
 377 igmp_joingroup(inm)
 378         struct in_multi *inm;
 379 {
 380
 381         if (inm->inm_addr.s_addr == igmp_all_hosts_group
 382             || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
 383                 inm->inm_timer = 0;
 384                 inm->inm_state = IGMP_OTHERMEMBER;
 385         } else {
 386                 inm->inm_rti = find_rti(inm->inm_ifp);
 387                 if (inm->inm_rti == NULL) return ENOMEM;
 388                 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
 389                 inm->inm_timer = IGMP_RANDOM_DELAY(
 390                                         IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
 391                 inm->inm_state = IGMP_IREPORTEDLAST;
 392                 igmp_timers_are_running = 1;
 393         }
 394         return 0;
 395 }
 396
 397 void
 398 igmp_leavegroup(inm)
 399         struct in_multi *inm;
 400 {
 401         if (inm->inm_state == IGMP_IREPORTEDLAST &&
 402             inm->inm_addr.s_addr != igmp_all_hosts_group &&
 403             !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
 404             inm->inm_rti->rti_type != IGMP_V1_ROUTER)
 405                 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
 406 }
 407
 408 void
 409 igmp_fasttimo()
 410 {
 411         struct in_multi *inm;
 412         struct in_multistep step;
 413
 414         /*
 415          * Quick check to see if any work needs to be done, in order
 416          * to minimize the overhead of fasttimo processing.
 417          */
 418
 419         if (!igmp_timers_are_running)
 420                 return;
 421
 422         igmp_timers_are_running = 0;
 423         IN_FIRST_MULTI(step, inm);
 424         while (inm != NULL) {
 425                 if (inm->inm_timer == 0) {
 426                         /* do nothing */
 427                 } else if (--inm->inm_timer == 0) {
 428                         igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
 429                         inm->inm_state = IGMP_IREPORTEDLAST;
 430                 } else {
 431                         igmp_timers_are_running = 1;
 432                 }
 433                 IN_NEXT_MULTI(step, inm);
 434         }
 435 }
 436
 437 void
 438 igmp_slowtimo()
 439 {
 440         struct router_info *rti =  Head;
 441
 442 #if IGMP_DEBUG
 443         printf("[igmp.c,_slowtimo] -- > entering \n");
 444 #endif
 445         while (rti) {
 446             if (rti->rti_type == IGMP_V1_ROUTER) {
 447                 rti->rti_time++;
 448                 if (rti->rti_time >= IGMP_AGE_THRESHOLD) {
 449                         rti->rti_type = IGMP_V2_ROUTER;
 450                 }
 451             }
 452             rti = rti->rti_next;
 453         }
 454 #if IGMP_DEBUG
 455         printf("[igmp.c,_slowtimo] -- > exiting \n");
 456 #endif
 457 }
 458
 459 static struct route igmprt;
 460
 461 static void
 462 igmp_sendpkt(inm, type, addr)
 463         struct in_multi *inm;
 464         int type;
 465         unsigned long addr;
 466 {
 467         struct mbuf *m;
 468         struct igmp *igmp;
 469         struct ip *ip;
 470         struct ip_moptions imo;
 471
 472         MGETHDR(m, M_DONTWAIT, MT_HEADER);
 473         if (m == NULL)
 474                 return;
 475
 476         m->m_pkthdr.rcvif = loif;
 477         m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
 478         MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
 479         m->m_data += sizeof(struct ip);
 480         m->m_len = IGMP_MINLEN;
 481         m->m_pkthdr.csum_flags = 0;
 482         m->m_pkthdr.csum_data = 0;
 483         igmp = mtod(m, struct igmp *);
 484         igmp->igmp_type   = type;
 485         igmp->igmp_code   = 0;
 486         igmp->igmp_group  = inm->inm_addr;
 487         igmp->igmp_cksum  = 0;
 488         igmp->igmp_cksum  = in_cksum(m, IGMP_MINLEN);
 489
 490         m->m_data -= sizeof(struct ip);
 491         m->m_len += sizeof(struct ip);
 492         ip = mtod(m, struct ip *);
 493         ip->ip_tos        = 0;
 494         ip->ip_len        = sizeof(struct ip) + IGMP_MINLEN;
 495         ip->ip_off        = 0;
 496         ip->ip_p          = IPPROTO_IGMP;
 497         ip->ip_src.s_addr = INADDR_ANY;
 498         ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
 499
 500         imo.imo_multicast_ifp  = inm->inm_ifp;
 501         imo.imo_multicast_ttl  = 1;
 502         imo.imo_multicast_vif  = -1;
 503         /*
 504          * Request loopback of the report if we are acting as a multicast
 505          * router, so that the process-level routing demon can hear it.
 506          */
 507         imo.imo_multicast_loop = (ip_mrouter != NULL);
 508
 509         /*
 510          * XXX
 511          * Do we have to worry about reentrancy here?  Don't think so.
 512          */
 513         ip_output(m, router_alert, &igmprt, 0, &imo);
 514
 515         ++igmpstat.igps_snd_reports;
 516 }