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. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)igmp.c 8.1 (Berkeley) 7/19/93 38 * $Id: igmp.c,v 1.14 1995/12/02 19:37:52 bde Exp $ 39 */ 40 41 /* 42 * Internet Group Management Protocol (IGMP) routines. 43 * 44 * Written by Steve Deering, Stanford, May 1988. 45 * Modified by Rosen Sharma, Stanford, Aug 1994. 46 * Modified by Bill Fenner, Xerox PARC, Feb 1995. 47 * 48 * MULTICAST Revision: 3.3.1.2 49 */ 50 51 #include <sys/param.h> 52 #include <sys/systm.h> 53 #include <sys/mbuf.h> 54 #include <sys/socket.h> 55 #include <sys/protosw.h> 56 #include <sys/kernel.h> 57 #include <sys/sysctl.h> 58 59 #include <net/if.h> 60 #include <net/route.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_var.h> 64 #include <netinet/in_systm.h> 65 #include <netinet/ip.h> 66 #include <netinet/ip_var.h> 67 #include <netinet/igmp.h> 68 #include <netinet/igmp_var.h> 69 70 static int fill_rti __P((struct in_multi *inm)); 71 static struct router_info * 72 find_rti __P((struct ifnet *ifp)); 73 74 static struct igmpstat igmpstat; 75 76 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD, 77 &igmpstat, igmpstat, ""); 78 79 static int igmp_timers_are_running; 80 static u_long igmp_all_hosts_group; 81 static u_long igmp_local_group; 82 static u_long igmp_local_group_mask; 83 static struct router_info *Head; 84 85 static void igmp_sendpkt(struct in_multi *, int); 86 static void igmp_sendleave(struct in_multi *); 87 88 void 89 igmp_init() 90 { 91 /* 92 * To avoid byte-swapping the same value over and over again. 93 */ 94 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 95 igmp_local_group = htonl(0xe0000000); /* 224.0.0.0 */ 96 igmp_local_group_mask = htonl(0xffffff00); /* ........^ */ 97 98 igmp_timers_are_running = 0; 99 100 Head = (struct router_info *) 0; 101 } 102 103 static int 104 fill_rti(inm) 105 struct in_multi *inm; 106 { 107 register struct router_info *rti = Head; 108 109 #ifdef IGMP_DEBUG 110 printf("[igmp.c, _fill_rti] --> entering \n"); 111 #endif 112 while (rti) { 113 if (rti->ifp == inm->inm_ifp) { 114 inm->inm_rti = rti; 115 #ifdef IGMP_DEBUG 116 printf("[igmp.c, _fill_rti] --> found old entry \n"); 117 #endif 118 if (rti->type == IGMP_OLD_ROUTER) 119 return IGMP_HOST_MEMBERSHIP_REPORT; 120 else 121 return IGMP_HOST_NEW_MEMBERSHIP_REPORT; 122 } 123 rti = rti->next; 124 } 125 MALLOC(rti, struct router_info *, sizeof *rti, M_MRTABLE, M_NOWAIT); 126 rti->ifp = inm->inm_ifp; 127 rti->type = IGMP_NEW_ROUTER; 128 rti->time = IGMP_AGE_THRESHOLD; 129 rti->next = Head; 130 Head = rti; 131 inm->inm_rti = rti; 132 #ifdef IGMP_DEBUG 133 printf("[igmp.c, _fill_rti] --> created new entry \n"); 134 #endif 135 return IGMP_HOST_NEW_MEMBERSHIP_REPORT; 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 #ifdef IGMP_DEBUG 145 printf("[igmp.c, _find_rti] --> entering \n"); 146 #endif 147 while (rti) { 148 if (rti->ifp == ifp) { 149 #ifdef IGMP_DEBUG 150 printf("[igmp.c, _find_rti] --> found old entry \n"); 151 #endif 152 return rti; 153 } 154 rti = rti->next; 155 } 156 MALLOC(rti, struct router_info *, sizeof *rti, M_MRTABLE, M_NOWAIT); 157 rti->ifp = ifp; 158 rti->type = IGMP_NEW_ROUTER; 159 rti->time = IGMP_AGE_THRESHOLD; 160 rti->next = Head; 161 Head = rti; 162 #ifdef IGMP_DEBUG 163 printf("[igmp.c, _find_rti] --> created an entry \n"); 164 #endif 165 return rti; 166 } 167 168 void 169 igmp_input(m, iphlen) 170 register struct mbuf *m; 171 register int iphlen; 172 { 173 register struct igmp *igmp; 174 register struct ip *ip; 175 register int igmplen; 176 register struct ifnet *ifp = m->m_pkthdr.rcvif; 177 register int minlen; 178 register struct in_multi *inm; 179 register struct in_ifaddr *ia; 180 struct in_multistep step; 181 struct router_info *rti; 182 183 int timer; /** timer value in the igmp query header **/ 184 185 ++igmpstat.igps_rcv_total; 186 187 ip = mtod(m, struct ip *); 188 igmplen = ip->ip_len; 189 190 /* 191 * Validate lengths 192 */ 193 if (igmplen < IGMP_MINLEN) { 194 ++igmpstat.igps_rcv_tooshort; 195 m_freem(m); 196 return; 197 } 198 minlen = iphlen + IGMP_MINLEN; 199 if ((m->m_flags & M_EXT || m->m_len < minlen) && 200 (m = m_pullup(m, minlen)) == 0) { 201 ++igmpstat.igps_rcv_tooshort; 202 return; 203 } 204 205 /* 206 * Validate checksum 207 */ 208 m->m_data += iphlen; 209 m->m_len -= iphlen; 210 igmp = mtod(m, struct igmp *); 211 if (in_cksum(m, igmplen)) { 212 ++igmpstat.igps_rcv_badsum; 213 m_freem(m); 214 return; 215 } 216 m->m_data -= iphlen; 217 m->m_len += iphlen; 218 219 ip = mtod(m, struct ip *); 220 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 221 rti = find_rti(ifp); 222 223 switch (igmp->igmp_type) { 224 225 case IGMP_HOST_MEMBERSHIP_QUERY: 226 ++igmpstat.igps_rcv_queries; 227 228 if (ifp->if_flags & IFF_LOOPBACK) 229 break; 230 231 if (igmp->igmp_code == 0) { 232 233 rti->type = IGMP_OLD_ROUTER; rti->time = 0; 234 235 /* 236 ** Do exactly as RFC 1112 says 237 */ 238 239 if (ip->ip_dst.s_addr != igmp_all_hosts_group) { 240 ++igmpstat.igps_rcv_badqueries; 241 m_freem(m); 242 return; 243 } 244 245 /* 246 * Start the timers in all of our membership records for 247 * the interface on which the query arrived, except those 248 * that are already running and those that belong to a 249 * "local" group (224.0.0.X). 250 */ 251 IN_FIRST_MULTI(step, inm); 252 while (inm != NULL) { 253 if (inm->inm_ifp == ifp 254 && inm->inm_timer == 0 255 && ((inm->inm_addr.s_addr 256 & igmp_local_group_mask) 257 != igmp_local_group)) { 258 259 inm->inm_state = IGMP_DELAYING_MEMBER; 260 inm->inm_timer = IGMP_RANDOM_DELAY( 261 IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ ); 262 263 igmp_timers_are_running = 1; 264 } 265 IN_NEXT_MULTI(step, inm); 266 } 267 } else { 268 /* 269 ** New Router 270 */ 271 272 if (!(m->m_flags & M_MCAST)) { 273 ++igmpstat.igps_rcv_badqueries; 274 m_freem(m); 275 return; 276 } 277 278 /* 279 * - Start the timers in all of our membership records 280 * that the query applies to for the interface on 281 * which the query arrived excl. those that belong 282 * to a "local" group (224.0.0.X) 283 * - For timers already running check if they need to 284 * be reset. 285 * - Use the igmp->igmp_code field as the maximum 286 * delay possible 287 */ 288 IN_FIRST_MULTI(step, inm); 289 while (inm != NULL) { 290 if (inm->inm_ifp == ifp && 291 (inm->inm_addr.s_addr & igmp_local_group_mask) != 292 igmp_local_group && 293 (ip->ip_dst.s_addr == igmp_all_hosts_group || 294 ip->ip_dst.s_addr == inm->inm_addr.s_addr)) { 295 switch(inm->inm_state) { 296 case IGMP_IDLE_MEMBER: 297 case IGMP_LAZY_MEMBER: 298 case IGMP_AWAKENING_MEMBER: 299 inm->inm_timer = IGMP_RANDOM_DELAY(timer); 300 igmp_timers_are_running = 1; 301 inm->inm_state = IGMP_DELAYING_MEMBER; 302 break; 303 case IGMP_DELAYING_MEMBER: 304 if (inm->inm_timer > timer) { 305 inm->inm_timer = IGMP_RANDOM_DELAY(timer); 306 igmp_timers_are_running = 1; 307 inm->inm_state = IGMP_DELAYING_MEMBER; 308 } 309 break; 310 case IGMP_SLEEPING_MEMBER: 311 inm->inm_state = IGMP_AWAKENING_MEMBER; 312 break; 313 } 314 } 315 IN_NEXT_MULTI(step, inm); 316 } 317 } 318 319 break; 320 321 case IGMP_HOST_MEMBERSHIP_REPORT: 322 /* 323 * an old report 324 */ 325 ++igmpstat.igps_rcv_reports; 326 327 if (ifp->if_flags & IFF_LOOPBACK) 328 break; 329 330 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr)) || 331 igmp->igmp_group.s_addr != ip->ip_dst.s_addr) { 332 ++igmpstat.igps_rcv_badreports; 333 m_freem(m); 334 return; 335 } 336 337 /* 338 * KLUDGE: if the IP source address of the report has an 339 * unspecified (i.e., zero) subnet number, as is allowed for 340 * a booting host, replace it with the correct subnet number 341 * so that a process-level multicast routing demon can 342 * determine which subnet it arrived from. This is necessary 343 * to compensate for the lack of any way for a process to 344 * determine the arrival interface of an incoming packet. 345 */ 346 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) { 347 IFP_TO_IA(ifp, ia); 348 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 349 } 350 351 /* 352 * If we belong to the group being reported, stop 353 * our timer for that group. 354 */ 355 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 356 357 if (inm != NULL) { 358 inm->inm_timer = 0; 359 ++igmpstat.igps_rcv_ourreports; 360 361 switch(inm->inm_state){ 362 case IGMP_IDLE_MEMBER: 363 case IGMP_LAZY_MEMBER: 364 case IGMP_AWAKENING_MEMBER: 365 case IGMP_SLEEPING_MEMBER: 366 inm->inm_state = IGMP_SLEEPING_MEMBER; 367 break; 368 case IGMP_DELAYING_MEMBER: 369 if (inm->inm_rti->type == IGMP_OLD_ROUTER) 370 inm->inm_state = IGMP_LAZY_MEMBER; 371 else 372 inm->inm_state = IGMP_SLEEPING_MEMBER; 373 break; 374 } 375 } 376 377 break; 378 379 case IGMP_HOST_NEW_MEMBERSHIP_REPORT: 380 /* 381 * a new report 382 */ 383 384 /* 385 * We can get confused and think there's someone 386 * else out there if we are a multicast router. 387 * For fast leave to work, we have to know that 388 * we are the only member. 389 */ 390 IFP_TO_IA(ifp, ia); 391 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 392 break; 393 394 ++igmpstat.igps_rcv_reports; 395 396 if (ifp->if_flags & IFF_LOOPBACK) 397 break; 398 399 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr)) || 400 igmp->igmp_group.s_addr != ip->ip_dst.s_addr) { 401 ++igmpstat.igps_rcv_badreports; 402 m_freem(m); 403 return; 404 } 405 406 /* 407 * KLUDGE: if the IP source address of the report has an 408 * unspecified (i.e., zero) subnet number, as is allowed for 409 * a booting host, replace it with the correct subnet number 410 * so that a process-level multicast routing demon can 411 * determine which subnet it arrived from. This is necessary 412 * to compensate for the lack of any way for a process to 413 * determine the arrival interface of an incoming packet. 414 */ 415 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) { 416 /* #ifndef MROUTING XXX - I don't think the ifdef is necessary */ 417 IFP_TO_IA(ifp, ia); 418 /* #endif */ 419 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 420 } 421 422 /* 423 * If we belong to the group being reported, stop 424 * our timer for that group. 425 */ 426 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 427 if (inm != NULL) { 428 inm->inm_timer = 0; 429 ++igmpstat.igps_rcv_ourreports; 430 431 switch(inm->inm_state){ 432 case IGMP_DELAYING_MEMBER: 433 case IGMP_IDLE_MEMBER: 434 inm->inm_state = IGMP_LAZY_MEMBER; 435 break; 436 case IGMP_AWAKENING_MEMBER: 437 inm->inm_state = IGMP_LAZY_MEMBER; 438 break; 439 case IGMP_LAZY_MEMBER: 440 case IGMP_SLEEPING_MEMBER: 441 break; 442 } 443 } 444 } 445 446 /* 447 * Pass all valid IGMP packets up to any process(es) listening 448 * on a raw IGMP socket. 449 */ 450 rip_input(m); 451 } 452 453 void 454 igmp_joingroup(inm) 455 struct in_multi *inm; 456 { 457 int s = splnet(); 458 459 inm->inm_state = IGMP_IDLE_MEMBER; 460 461 if ((inm->inm_addr.s_addr & igmp_local_group_mask) == igmp_local_group 462 || inm->inm_ifp->if_flags & IFF_LOOPBACK) 463 inm->inm_timer = 0; 464 else { 465 igmp_sendpkt(inm,fill_rti(inm)); 466 inm->inm_timer = IGMP_RANDOM_DELAY( 467 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 468 inm->inm_state = IGMP_DELAYING_MEMBER; 469 igmp_timers_are_running = 1; 470 } 471 splx(s); 472 } 473 474 void 475 igmp_leavegroup(inm) 476 struct in_multi *inm; 477 { 478 switch(inm->inm_state) { 479 case IGMP_DELAYING_MEMBER: 480 case IGMP_IDLE_MEMBER: 481 if (((inm->inm_addr.s_addr & igmp_local_group_mask) 482 != igmp_local_group) 483 && !(inm->inm_ifp->if_flags & IFF_LOOPBACK)) 484 if (inm->inm_rti->type != IGMP_OLD_ROUTER) 485 igmp_sendleave(inm); 486 break; 487 case IGMP_LAZY_MEMBER: 488 case IGMP_AWAKENING_MEMBER: 489 case IGMP_SLEEPING_MEMBER: 490 break; 491 } 492 } 493 494 void 495 igmp_fasttimo() 496 { 497 register struct in_multi *inm; 498 struct in_multistep step; 499 int s; 500 501 /* 502 * Quick check to see if any work needs to be done, in order 503 * to minimize the overhead of fasttimo processing. 504 */ 505 506 if (!igmp_timers_are_running) 507 return; 508 509 s = splnet(); 510 igmp_timers_are_running = 0; 511 IN_FIRST_MULTI(step, inm); 512 while (inm != NULL) { 513 if (inm->inm_timer == 0) { 514 /* do nothing */ 515 } else if (--inm->inm_timer == 0) { 516 if (inm->inm_state == IGMP_DELAYING_MEMBER) { 517 if (inm->inm_rti->type == IGMP_OLD_ROUTER) 518 igmp_sendpkt(inm, IGMP_HOST_MEMBERSHIP_REPORT); 519 else 520 igmp_sendpkt(inm, IGMP_HOST_NEW_MEMBERSHIP_REPORT); 521 inm->inm_state = IGMP_IDLE_MEMBER; 522 } 523 } else { 524 igmp_timers_are_running = 1; 525 } 526 IN_NEXT_MULTI(step, inm); 527 } 528 splx(s); 529 } 530 531 void 532 igmp_slowtimo() 533 { 534 int s = splnet(); 535 register struct router_info *rti = Head; 536 537 #ifdef IGMP_DEBUG 538 printf("[igmp.c,_slowtimo] -- > entering \n"); 539 #endif 540 while (rti) { 541 rti->time ++; 542 if (rti->time >= IGMP_AGE_THRESHOLD){ 543 rti->type = IGMP_NEW_ROUTER; 544 rti->time = IGMP_AGE_THRESHOLD; 545 } 546 rti = rti->next; 547 } 548 #ifdef IGMP_DEBUG 549 printf("[igmp.c,_slowtimo] -- > exiting \n"); 550 #endif 551 splx(s); 552 } 553 554 static void 555 igmp_sendpkt(inm, type) 556 struct in_multi *inm; 557 int type; 558 { 559 struct mbuf *m; 560 struct igmp *igmp; 561 struct ip *ip; 562 struct ip_moptions *imo; 563 564 MGETHDR(m, M_DONTWAIT, MT_HEADER); 565 if (m == NULL) 566 return; 567 568 MALLOC(imo, struct ip_moptions *, sizeof *imo, M_IPMOPTS, M_DONTWAIT); 569 if (!imo) { 570 m_free(m); 571 return; 572 } 573 574 m->m_pkthdr.rcvif = loif; 575 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 576 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 577 m->m_data += sizeof(struct ip); 578 m->m_len = IGMP_MINLEN; 579 igmp = mtod(m, struct igmp *); 580 igmp->igmp_type = type; 581 igmp->igmp_code = 0; 582 igmp->igmp_group = inm->inm_addr; 583 igmp->igmp_cksum = 0; 584 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 585 586 m->m_data -= sizeof(struct ip); 587 m->m_len += sizeof(struct ip); 588 ip = mtod(m, struct ip *); 589 ip->ip_tos = 0; 590 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 591 ip->ip_off = 0; 592 ip->ip_p = IPPROTO_IGMP; 593 ip->ip_src.s_addr = INADDR_ANY; 594 ip->ip_dst = igmp->igmp_group; 595 596 imo->imo_multicast_ifp = inm->inm_ifp; 597 imo->imo_multicast_ttl = 1; 598 imo->imo_multicast_vif = -1; 599 /* 600 * Request loopback of the report if we are acting as a multicast 601 * router, so that the process-level routing demon can hear it. 602 */ 603 imo->imo_multicast_loop = (ip_mrouter != NULL); 604 605 ip_output(m, (struct mbuf *)0, (struct route *)0, 0, imo); 606 607 FREE(imo, M_IPMOPTS); 608 ++igmpstat.igps_snd_reports; 609 } 610 611 static void 612 igmp_sendleave(inm) 613 struct in_multi *inm; 614 { 615 igmp_sendpkt(inm, IGMP_HOST_LEAVE_MESSAGE); 616 } 617