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 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
  93
  94 static struct router_info *
  95                 find_rti __P((struct ifnet *ifp));
  96
  97 static struct igmpstat igmpstat;
  98
  99 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD,
 100         &igmpstat, igmpstat, "");
 101
 102 static int igmp_timers_are_running;
 103 static u_long igmp_all_hosts_group;
 104 static u_long igmp_all_rtrs_group;
 105 static struct mbuf *router_alert;
 106 static struct router_info *Head;
 107
 108 static void igmp_sendpkt __P((struct in_multi *, int, unsigned long));
 109
 110 void
 111 igmp_init()
 112 {
 113         struct ipoption *ra;
 114
 115         /*
 116          * To avoid byte-swapping the same value over and over again.
 117          */
 118         igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
 119         igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
 120
 121         igmp_timers_are_running = 0;
 122
 123         /*
 124          * Construct a Router Alert option to use in outgoing packets
 125          */
 126         MGET(router_alert, M_DONTWAIT, MT_DATA);
 127         ra = mtod(router_alert, struct ipoption *);
 128         ra->ipopt_dst.s_addr = 0;
 129         ra->ipopt_list[0] = IPOPT_RA;   /* Router Alert Option */
 130         ra->ipopt_list[1] = 0x04;       /* 4 bytes long */
 131         ra->ipopt_list[2] = 0x00;
 132         ra->ipopt_list[3] = 0x00;
 133         router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
 134
 135         Head = (struct router_info *) 0;
 136 }
 137
 138 static struct router_info *
 139 find_rti(ifp)
 140         struct ifnet *ifp;
 141 {
 142         register struct router_info *rti = Head;
 143
 144 #if IGMP_DEBUG
 145         printf("[igmp.c, _find_rti] --> entering \n");
 146 #endif
 147         while (rti) {
 148                 if (rti->rti_ifp == ifp) {
 149 #if IGMP_DEBUG
 150                         printf("[igmp.c, _find_rti] --> found old entry \n");
 151 #endif
 152                         return rti;
 153                 }
 154                 rti = rti->rti_next;
 155         }
 156
 157 #if ISFB31
 158         MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT);
 159 #else
 160         MALLOC(rti, struct router_info *, sizeof *rti, M_TEMP, M_WAITOK);
 161 #endif
 162         rti->rti_ifp = ifp;
 163         rti->rti_type = IGMP_V2_ROUTER;
 164         rti->rti_time = 0;
 165         rti->rti_next = Head;
 166         Head = rti;
 167 #if IGMP_DEBUG
 168         printf("[igmp.c, _find_rti] --> created an entry \n");
 169 #endif
 170         return rti;
 171 }
 172
 173 void
 174 igmp_input(m, iphlen)
 175         register struct mbuf *m;
 176         register int iphlen;
 177 {
 178         register struct igmp *igmp;
 179         register struct ip *ip;
 180         register int igmplen;
 181         register struct ifnet *ifp = m->m_pkthdr.rcvif;
 182         register int minlen;
 183         register struct in_multi *inm;
 184         register struct in_ifaddr *ia;
 185         struct in_multistep step;
 186         struct router_info *rti;
 187
 188         int timer; /** timer value in the igmp query header **/
 189
 190         ++igmpstat.igps_rcv_total;
 191
 192         ip = mtod(m, struct ip *);
 193         igmplen = ip->ip_len;
 194
 195         /*
 196          * Validate lengths
 197          */
 198         if (igmplen < IGMP_MINLEN) {
 199                 ++igmpstat.igps_rcv_tooshort;
 200                 m_freem(m);
 201                 return;
 202         }
 203         minlen = iphlen + IGMP_MINLEN;
 204         if ((m->m_flags & M_EXT || m->m_len < minlen) &&
 205             (m = m_pullup(m, minlen)) == 0) {
 206                 ++igmpstat.igps_rcv_tooshort;
 207                 return;
 208         }
 209
 210         /*
 211          * Validate checksum
 212          */
 213         m->m_data += iphlen;
 214         m->m_len -= iphlen;
 215         igmp = mtod(m, struct igmp *);
 216         if (in_cksum(m, igmplen)) {
 217                 ++igmpstat.igps_rcv_badsum;
 218                 m_freem(m);
 219                 return;
 220         }
 221         m->m_data -= iphlen;
 222         m->m_len += iphlen;
 223
 224         ip = mtod(m, struct ip *);
 225         timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
 226         if (timer == 0)
 227                 timer = 1;
 228         rti = find_rti(ifp);
 229
 230         /*
 231          * In the IGMPv2 specification, there are 3 states and a flag.
 232          *
 233          * In Non-Member state, we simply don't have a membership record.
 234          * In Delaying Member state, our timer is running (inm->inm_timer)
 235          * In Idle Member state, our timer is not running (inm->inm_timer==0)
 236          *
 237          * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
 238          * we have heard a report from another member, or IGMP_IREPORTEDLAST
 239          * if I sent the last report.
 240          */
 241         switch (igmp->igmp_type) {
 242
 243         case IGMP_MEMBERSHIP_QUERY:
 244                 ++igmpstat.igps_rcv_queries;
 245
 246                 if (ifp->if_flags & IFF_LOOPBACK)
 247                         break;
 248
 249                 if (igmp->igmp_code == 0) {
 250                         /*
 251                          * Old router.  Remember that the querier on this
 252                          * interface is old, and set the timer to the
 253                          * value in RFC 1112.
 254                          */
 255
 256                         rti->rti_type = IGMP_V1_ROUTER;
 257                         rti->rti_time = 0;
 258
 259                         timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
 260
 261                         if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
 262                             igmp->igmp_group.s_addr != 0) {
 263                                 ++igmpstat.igps_rcv_badqueries;
 264                                 m_freem(m);
 265                                 return;
 266                         }
 267                 } else {
 268                         /*
 269                          * New router.  Simply do the new validity check.
 270                          */
 271
 272                         if (igmp->igmp_group.s_addr != 0 &&
 273                             !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
 274                                 ++igmpstat.igps_rcv_badqueries;
 275                                 m_freem(m);
 276                                 return;
 277                         }
 278                 }
 279
 280                 /*
 281                  * - Start the timers in all of our membership records
 282                  *   that the query applies to for the interface on
 283                  *   which the query arrived excl. those that belong
 284                  *   to the "all-hosts" group (224.0.0.1).
 285                  * - Restart any timer that is already running but has
 286                  *   a value longer than the requested timeout.
 287                  * - Use the value specified in the query message as
 288                  *   the maximum timeout.
 289                  */
 290                 IN_FIRST_MULTI(step, inm);
 291                 while (inm != NULL) {
 292                         if (inm->inm_ifp == ifp &&
 293                             inm->inm_addr.s_addr != igmp_all_hosts_group &&
 294                             (igmp->igmp_group.s_addr == 0 ||
 295                              igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
 296                                 if (inm->inm_timer == 0 ||
 297                                     inm->inm_timer > timer) {
 298                                         inm->inm_timer =
 299                                                 IGMP_RANDOM_DELAY(timer);
 300                                         igmp_timers_are_running = 1;
 301                                 }
 302                         }
 303                         IN_NEXT_MULTI(step, inm);
 304                 }
 305
 306                 break;
 307
 308         case IGMP_V1_MEMBERSHIP_REPORT:
 309         case IGMP_V2_MEMBERSHIP_REPORT:
 310                 /*
 311                  * For fast leave to work, we have to know that we are the
 312                  * last person to send a report for this group.  Reports
 313                  * can potentially get looped back if we are a multicast
 314                  * router, so discard reports sourced by me.
 315                  */
 316                 IFP_TO_IA(ifp, ia);
 317                 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
 318                         break;
 319
 320                 ++igmpstat.igps_rcv_reports;
 321
 322                 if (ifp->if_flags & IFF_LOOPBACK)
 323                         break;
 324
 325                 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
 326                         ++igmpstat.igps_rcv_badreports;
 327                         m_freem(m);
 328                         return;
 329                 }
 330
 331                 /*
 332                  * KLUDGE: if the IP source address of the report has an
 333                  * unspecified (i.e., zero) subnet number, as is allowed for
 334                  * a booting host, replace it with the correct subnet number
 335                  * so that a process-level multicast routing demon can
 336                  * determine which subnet it arrived from.  This is necessary
 337                  * to compensate for the lack of any way for a process to
 338                  * determine the arrival interface of an incoming packet.
 339                  */
 340                 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
 341                         if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
 342
 343                 /*
 344                  * If we belong to the group being reported, stop
 345                  * our timer for that group.
 346                  */
 347                 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
 348
 349                 if (inm != NULL) {
 350                         inm->inm_timer = 0;
 351                         ++igmpstat.igps_rcv_ourreports;
 352
 353                         inm->inm_state = IGMP_OTHERMEMBER;
 354                 }
 355
 356                 break;
 357         }
 358
 359         /*
 360          * Pass all valid IGMP packets up to any process(es) listening
 361          * on a raw IGMP socket.
 362          */
 363         rip_input(m, iphlen);
 364 }
 365
 366 void
 367 igmp_joingroup(inm)
 368         struct in_multi *inm;
 369 {
 370         int s = splnet();
 371
 372         if (inm->inm_addr.s_addr == igmp_all_hosts_group
 373             || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
 374                 inm->inm_timer = 0;
 375                 inm->inm_state = IGMP_OTHERMEMBER;
 376         } else {
 377                 inm->inm_rti = find_rti(inm->inm_ifp);
 378                 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
 379                 inm->inm_timer = IGMP_RANDOM_DELAY(
 380                                         IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
 381                 inm->inm_state = IGMP_IREPORTEDLAST;
 382                 igmp_timers_are_running = 1;
 383         }
 384         splx(s);
 385 }
 386
 387 void
 388 igmp_leavegroup(inm)
 389         struct in_multi *inm;
 390 {
 391         if (inm->inm_state == IGMP_IREPORTEDLAST &&
 392             inm->inm_addr.s_addr != igmp_all_hosts_group &&
 393             !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
 394             inm->inm_rti->rti_type != IGMP_V1_ROUTER)
 395                 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
 396 }
 397
 398 void
 399 igmp_fasttimo()
 400 {
 401         register struct in_multi *inm;
 402         struct in_multistep step;
 403         int s;
 404
 405         /*
 406          * Quick check to see if any work needs to be done, in order
 407          * to minimize the overhead of fasttimo processing.
 408          */
 409
 410         if (!igmp_timers_are_running)
 411                 return;
 412
 413         s = splnet();
 414         igmp_timers_are_running = 0;
 415         IN_FIRST_MULTI(step, inm);
 416         while (inm != NULL) {
 417                 if (inm->inm_timer == 0) {
 418                         /* do nothing */
 419                 } else if (--inm->inm_timer == 0) {
 420                         igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
 421                         inm->inm_state = IGMP_IREPORTEDLAST;
 422                 } else {
 423                         igmp_timers_are_running = 1;
 424                 }
 425                 IN_NEXT_MULTI(step, inm);
 426         }
 427         splx(s);
 428 }
 429
 430 void
 431 igmp_slowtimo()
 432 {
 433         int s = splnet();
 434         register struct router_info *rti =  Head;
 435
 436 #if IGMP_DEBUG
 437         printf("[igmp.c,_slowtimo] -- > entering \n");
 438 #endif
 439         while (rti) {
 440             if (rti->rti_type == IGMP_V1_ROUTER) {
 441                 rti->rti_time++;
 442                 if (rti->rti_time >= IGMP_AGE_THRESHOLD) {
 443                         rti->rti_type = IGMP_V2_ROUTER;
 444                 }
 445             }
 446             rti = rti->rti_next;
 447         }
 448 #if IGMP_DEBUG
 449         printf("[igmp.c,_slowtimo] -- > exiting \n");
 450 #endif
 451         splx(s);
 452 }
 453
 454 static struct route igmprt;
 455
 456 static void
 457 igmp_sendpkt(inm, type, addr)
 458         struct in_multi *inm;
 459         int type;
 460         unsigned long addr;
 461 {
 462         struct mbuf *m;
 463         struct igmp *igmp;
 464         struct ip *ip;
 465         struct ip_moptions imo;
 466
 467         MGETHDR(m, M_DONTWAIT, MT_HEADER);
 468         if (m == NULL)
 469                 return;
 470
 471         m->m_pkthdr.rcvif = loif;
 472         m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
 473         MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
 474         m->m_data += sizeof(struct ip);
 475         m->m_len = IGMP_MINLEN;
 476         m->m_pkthdr.csum_flags = 0;
 477         m->m_pkthdr.csum_data = 0;
 478         igmp = mtod(m, struct igmp *);
 479         igmp->igmp_type   = type;
 480         igmp->igmp_code   = 0;
 481         igmp->igmp_group  = inm->inm_addr;
 482         igmp->igmp_cksum  = 0;
 483         igmp->igmp_cksum  = in_cksum(m, IGMP_MINLEN);
 484
 485         m->m_data -= sizeof(struct ip);
 486         m->m_len += sizeof(struct ip);
 487         ip = mtod(m, struct ip *);
 488         ip->ip_tos        = 0;
 489         ip->ip_len        = sizeof(struct ip) + IGMP_MINLEN;
 490         ip->ip_off        = 0;
 491         ip->ip_p          = IPPROTO_IGMP;
 492         ip->ip_src.s_addr = INADDR_ANY;
 493         ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
 494
 495         imo.imo_multicast_ifp  = inm->inm_ifp;
 496         imo.imo_multicast_ttl  = 1;
 497         imo.imo_multicast_vif  = -1;
 498         /*
 499          * Request loopback of the report if we are acting as a multicast
 500          * router, so that the process-level routing demon can hear it.
 501          */
 502         imo.imo_multicast_loop = (ip_mrouter != NULL);
 503
 504         /*
 505          * XXX
 506          * Do we have to worry about reentrancy here?  Don't think so.
 507          */
 508 #if IPSEC
 509         m->m_pkthdr.rcvif = NULL;
 510 #endif /*IPSEC*/
 511         ip_output(m, router_alert, &igmprt, 0, &imo);
 512
 513         ++igmpstat.igps_snd_reports;
 514 }