Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/netinet/igmp.c
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1 /* $NetBSD: igmp.c,v 1.41 2005/02/03 03:49:01 perry Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * Internet Group Management Protocol (IGMP) routines. 34 * 35 * Written by Steve Deering, Stanford, May 1988. 36 * Modified by Rosen Sharma, Stanford, Aug 1994. 37 * Modified by Bill Fenner, Xerox PARC, Feb 1995. 38 * 39 * MULTICAST Revision: 1.3 40 */ 41 42 #include <sys/cdefs.h> 43 __KERNEL_RCSID(0, "$NetBSD: igmp.c,v 1.41 2005/02/03 03:49:01 perry Exp $"); 44 45 #include "opt_mrouting.h" 46 47 #include <sys/param.h> 48 #include <sys/mbuf.h> 49 #include <sys/socket.h> 50 #include <sys/protosw.h> 51 #include <sys/systm.h> 52 53 #include <net/if.h> 54 #include <net/route.h> 55 56 #include <netinet/in.h> 57 #include <netinet/in_var.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/ip.h> 60 #include <netinet/ip_var.h> 61 #include <netinet/igmp.h> 62 #include <netinet/igmp_var.h> 63 64 #include <machine/stdarg.h> 65 66 #define IP_MULTICASTOPTS 0 67 68 POOL_INIT(igmp_rti_pool, sizeof(struct router_info), 0, 0, 0, "igmppl", NULL); 69 struct igmpstat igmpstat; 70 int igmp_timers_are_running; 71 static LIST_HEAD(, router_info) rti_head = LIST_HEAD_INITIALIZER(rti_head); 72 73 void igmp_sendpkt(struct in_multi *, int); 74 static int rti_fill(struct in_multi *); 75 static struct router_info *rti_find(struct ifnet *); 76 static void rti_delete(struct ifnet *); 77 78 static int 79 rti_fill(struct in_multi *inm) 80 { 81 struct router_info *rti; 82 83 LIST_FOREACH(rti, &rti_head, rti_link) { 84 if (rti->rti_ifp == inm->inm_ifp) { 85 inm->inm_rti = rti; 86 if (rti->rti_type == IGMP_v1_ROUTER) 87 return (IGMP_v1_HOST_MEMBERSHIP_REPORT); 88 else 89 return (IGMP_v2_HOST_MEMBERSHIP_REPORT); 90 } 91 } 92 93 rti = pool_get(&igmp_rti_pool, PR_NOWAIT); 94 if (rti == NULL) 95 return 0; 96 rti->rti_ifp = inm->inm_ifp; 97 rti->rti_type = IGMP_v2_ROUTER; 98 LIST_INSERT_HEAD(&rti_head, rti, rti_link); 99 inm->inm_rti = rti; 100 return (IGMP_v2_HOST_MEMBERSHIP_REPORT); 101 } 102 103 static struct router_info * 104 rti_find(struct ifnet *ifp) 105 { 106 struct router_info *rti; 107 108 LIST_FOREACH(rti, &rti_head, rti_link) { 109 if (rti->rti_ifp == ifp) 110 return (rti); 111 } 112 113 rti = pool_get(&igmp_rti_pool, PR_NOWAIT); 114 if (rti == NULL) 115 return NULL; 116 rti->rti_ifp = ifp; 117 rti->rti_type = IGMP_v2_ROUTER; 118 LIST_INSERT_HEAD(&rti_head, rti, rti_link); 119 return (rti); 120 } 121 122 static void 123 rti_delete(struct ifnet *ifp) 124 { 125 struct router_info *rti; 126 127 LIST_FOREACH(rti, &rti_head, rti_link) { 128 if (rti->rti_ifp == ifp) { 129 LIST_REMOVE(rti, rti_link); 130 pool_put(&igmp_rti_pool, rti); 131 return; 132 } 133 } 134 } 135 136 void 137 igmp_input(struct mbuf *m, ...) 138 { 139 int proto; 140 int iphlen; 141 struct ifnet *ifp = m->m_pkthdr.rcvif; 142 struct ip *ip = mtod(m, struct ip *); 143 struct igmp *igmp; 144 u_int minlen; 145 struct in_multi *inm; 146 struct in_multistep step; 147 struct router_info *rti; 148 struct in_ifaddr *ia; 149 u_int timer; 150 va_list ap; 151 u_int16_t ip_len; 152 153 va_start(ap, m); 154 iphlen = va_arg(ap, int); 155 proto = va_arg(ap, int); 156 va_end(ap); 157 158 ++igmpstat.igps_rcv_total; 159 160 /* 161 * Validate lengths 162 */ 163 minlen = iphlen + IGMP_MINLEN; 164 ip_len = ntohs(ip->ip_len); 165 if (ip_len < minlen) { 166 ++igmpstat.igps_rcv_tooshort; 167 m_freem(m); 168 return; 169 } 170 if (((m->m_flags & M_EXT) && (ip->ip_src.s_addr & IN_CLASSA_NET) == 0) 171 || m->m_len < minlen) { 172 if ((m = m_pullup(m, minlen)) == 0) { 173 ++igmpstat.igps_rcv_tooshort; 174 return; 175 } 176 ip = mtod(m, struct ip *); 177 } 178 179 /* 180 * Validate checksum 181 */ 182 m->m_data += iphlen; 183 m->m_len -= iphlen; 184 igmp = mtod(m, struct igmp *); 185 /* No need to assert alignment here. */ 186 if (in_cksum(m, ip_len - iphlen)) { 187 ++igmpstat.igps_rcv_badsum; 188 m_freem(m); 189 return; 190 } 191 m->m_data -= iphlen; 192 m->m_len += iphlen; 193 194 switch (igmp->igmp_type) { 195 196 case IGMP_HOST_MEMBERSHIP_QUERY: 197 ++igmpstat.igps_rcv_queries; 198 199 if (ifp->if_flags & IFF_LOOPBACK) 200 break; 201 202 if (igmp->igmp_code == 0) { 203 rti = rti_find(ifp); 204 if (rti == NULL) 205 break; 206 rti->rti_type = IGMP_v1_ROUTER; 207 rti->rti_age = 0; 208 209 if (ip->ip_dst.s_addr != INADDR_ALLHOSTS_GROUP) { 210 ++igmpstat.igps_rcv_badqueries; 211 m_freem(m); 212 return; 213 } 214 215 /* 216 * Start the timers in all of our membership records 217 * for the interface on which the query arrived, 218 * except those that are already running and those 219 * that belong to a "local" group (224.0.0.X). 220 */ 221 IN_FIRST_MULTI(step, inm); 222 while (inm != NULL) { 223 if (inm->inm_ifp == ifp && 224 inm->inm_timer == 0 && 225 !IN_LOCAL_GROUP(inm->inm_addr.s_addr)) { 226 inm->inm_state = IGMP_DELAYING_MEMBER; 227 inm->inm_timer = IGMP_RANDOM_DELAY( 228 IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ); 229 igmp_timers_are_running = 1; 230 } 231 IN_NEXT_MULTI(step, inm); 232 } 233 } else { 234 if (!IN_MULTICAST(ip->ip_dst.s_addr)) { 235 ++igmpstat.igps_rcv_badqueries; 236 m_freem(m); 237 return; 238 } 239 240 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 241 if (timer == 0) 242 timer =1; 243 244 /* 245 * Start the timers in all of our membership records 246 * for the interface on which the query arrived, 247 * except those that are already running and those 248 * that belong to a "local" group (224.0.0.X). For 249 * timers already running, check if they need to be 250 * reset. 251 */ 252 IN_FIRST_MULTI(step, inm); 253 while (inm != NULL) { 254 if (inm->inm_ifp == ifp && 255 !IN_LOCAL_GROUP(inm->inm_addr.s_addr) && 256 (ip->ip_dst.s_addr == INADDR_ALLHOSTS_GROUP || 257 in_hosteq(ip->ip_dst, inm->inm_addr))) { 258 switch (inm->inm_state) { 259 case IGMP_DELAYING_MEMBER: 260 if (inm->inm_timer <= timer) 261 break; 262 /* FALLTHROUGH */ 263 case IGMP_IDLE_MEMBER: 264 case IGMP_LAZY_MEMBER: 265 case IGMP_AWAKENING_MEMBER: 266 inm->inm_state = 267 IGMP_DELAYING_MEMBER; 268 inm->inm_timer = 269 IGMP_RANDOM_DELAY(timer); 270 igmp_timers_are_running = 1; 271 break; 272 case IGMP_SLEEPING_MEMBER: 273 inm->inm_state = 274 IGMP_AWAKENING_MEMBER; 275 break; 276 } 277 } 278 IN_NEXT_MULTI(step, inm); 279 } 280 } 281 282 break; 283 284 case IGMP_v1_HOST_MEMBERSHIP_REPORT: 285 ++igmpstat.igps_rcv_reports; 286 287 if (ifp->if_flags & IFF_LOOPBACK) 288 break; 289 290 if (!IN_MULTICAST(igmp->igmp_group.s_addr) || 291 !in_hosteq(igmp->igmp_group, ip->ip_dst)) { 292 ++igmpstat.igps_rcv_badreports; 293 m_freem(m); 294 return; 295 } 296 297 /* 298 * KLUDGE: if the IP source address of the report has an 299 * unspecified (i.e., zero) subnet number, as is allowed for 300 * a booting host, replace it with the correct subnet number 301 * so that a process-level multicast routing daemon can 302 * determine which subnet it arrived from. This is necessary 303 * to compensate for the lack of any way for a process to 304 * determine the arrival interface of an incoming packet. 305 */ 306 if ((ip->ip_src.s_addr & IN_CLASSA_NET) == 0) { 307 IFP_TO_IA(ifp, ia); /* XXX */ 308 if (ia) 309 ip->ip_src.s_addr = ia->ia_subnet; 310 } 311 312 /* 313 * If we belong to the group being reported, stop 314 * our timer for that group. 315 */ 316 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 317 if (inm != NULL) { 318 inm->inm_timer = 0; 319 ++igmpstat.igps_rcv_ourreports; 320 321 switch (inm->inm_state) { 322 case IGMP_IDLE_MEMBER: 323 case IGMP_LAZY_MEMBER: 324 case IGMP_AWAKENING_MEMBER: 325 case IGMP_SLEEPING_MEMBER: 326 inm->inm_state = IGMP_SLEEPING_MEMBER; 327 break; 328 case IGMP_DELAYING_MEMBER: 329 if (inm->inm_rti->rti_type == IGMP_v1_ROUTER) 330 inm->inm_state = IGMP_LAZY_MEMBER; 331 else 332 inm->inm_state = IGMP_SLEEPING_MEMBER; 333 break; 334 } 335 } 336 337 break; 338 339 case IGMP_v2_HOST_MEMBERSHIP_REPORT: 340 #ifdef MROUTING 341 /* 342 * Make sure we don't hear our own membership report. Fast 343 * leave requires knowing that we are the only member of a 344 * group. 345 */ 346 IFP_TO_IA(ifp, ia); /* XXX */ 347 if (ia && in_hosteq(ip->ip_src, ia->ia_addr.sin_addr)) 348 break; 349 #endif 350 351 ++igmpstat.igps_rcv_reports; 352 353 if (ifp->if_flags & IFF_LOOPBACK) 354 break; 355 356 if (!IN_MULTICAST(igmp->igmp_group.s_addr) || 357 !in_hosteq(igmp->igmp_group, ip->ip_dst)) { 358 ++igmpstat.igps_rcv_badreports; 359 m_freem(m); 360 return; 361 } 362 363 /* 364 * KLUDGE: if the IP source address of the report has an 365 * unspecified (i.e., zero) subnet number, as is allowed for 366 * a booting host, replace it with the correct subnet number 367 * so that a process-level multicast routing daemon can 368 * determine which subnet it arrived from. This is necessary 369 * to compensate for the lack of any way for a process to 370 * determine the arrival interface of an incoming packet. 371 */ 372 if ((ip->ip_src.s_addr & IN_CLASSA_NET) == 0) { 373 #ifndef MROUTING 374 IFP_TO_IA(ifp, ia); /* XXX */ 375 #endif 376 if (ia) 377 ip->ip_src.s_addr = ia->ia_subnet; 378 } 379 380 /* 381 * If we belong to the group being reported, stop 382 * our timer for that group. 383 */ 384 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 385 if (inm != NULL) { 386 inm->inm_timer = 0; 387 ++igmpstat.igps_rcv_ourreports; 388 389 switch (inm->inm_state) { 390 case IGMP_DELAYING_MEMBER: 391 case IGMP_IDLE_MEMBER: 392 case IGMP_AWAKENING_MEMBER: 393 inm->inm_state = IGMP_LAZY_MEMBER; 394 break; 395 case IGMP_LAZY_MEMBER: 396 case IGMP_SLEEPING_MEMBER: 397 break; 398 } 399 } 400 401 break; 402 403 } 404 405 /* 406 * Pass all valid IGMP packets up to any process(es) listening 407 * on a raw IGMP socket. 408 */ 409 rip_input(m, iphlen, proto); 410 return; 411 } 412 413 int 414 igmp_joingroup(struct in_multi *inm) 415 { 416 int report_type; 417 int s = splsoftnet(); 418 419 inm->inm_state = IGMP_IDLE_MEMBER; 420 421 if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) && 422 (inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0) { 423 report_type = rti_fill(inm); 424 if (report_type == 0) { 425 splx(s); 426 return ENOMEM; 427 } 428 igmp_sendpkt(inm, report_type); 429 inm->inm_state = IGMP_DELAYING_MEMBER; 430 inm->inm_timer = IGMP_RANDOM_DELAY( 431 IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ); 432 igmp_timers_are_running = 1; 433 } else 434 inm->inm_timer = 0; 435 splx(s); 436 return 0; 437 } 438 439 void 440 igmp_leavegroup(struct in_multi *inm) 441 { 442 443 switch (inm->inm_state) { 444 case IGMP_DELAYING_MEMBER: 445 case IGMP_IDLE_MEMBER: 446 if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) && 447 (inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0) 448 if (inm->inm_rti->rti_type != IGMP_v1_ROUTER) 449 igmp_sendpkt(inm, IGMP_HOST_LEAVE_MESSAGE); 450 break; 451 case IGMP_LAZY_MEMBER: 452 case IGMP_AWAKENING_MEMBER: 453 case IGMP_SLEEPING_MEMBER: 454 break; 455 } 456 } 457 458 void 459 igmp_fasttimo(void) 460 { 461 struct in_multi *inm; 462 struct in_multistep step; 463 int s; 464 465 /* 466 * Quick check to see if any work needs to be done, in order 467 * to minimize the overhead of fasttimo processing. 468 */ 469 if (!igmp_timers_are_running) 470 return; 471 472 s = splsoftnet(); 473 igmp_timers_are_running = 0; 474 IN_FIRST_MULTI(step, inm); 475 while (inm != NULL) { 476 if (inm->inm_timer == 0) { 477 /* do nothing */ 478 } else if (--inm->inm_timer == 0) { 479 if (inm->inm_state == IGMP_DELAYING_MEMBER) { 480 if (inm->inm_rti->rti_type == IGMP_v1_ROUTER) 481 igmp_sendpkt(inm, 482 IGMP_v1_HOST_MEMBERSHIP_REPORT); 483 else 484 igmp_sendpkt(inm, 485 IGMP_v2_HOST_MEMBERSHIP_REPORT); 486 inm->inm_state = IGMP_IDLE_MEMBER; 487 } 488 } else { 489 igmp_timers_are_running = 1; 490 } 491 IN_NEXT_MULTI(step, inm); 492 } 493 splx(s); 494 } 495 496 void 497 igmp_slowtimo(void) 498 { 499 struct router_info *rti; 500 int s; 501 502 s = splsoftnet(); 503 LIST_FOREACH(rti, &rti_head, rti_link) { 504 if (rti->rti_type == IGMP_v1_ROUTER && 505 ++rti->rti_age >= IGMP_AGE_THRESHOLD) { 506 rti->rti_type = IGMP_v2_ROUTER; 507 } 508 } 509 splx(s); 510 } 511 512 void 513 igmp_sendpkt(struct in_multi *inm, int type) 514 { 515 struct mbuf *m; 516 struct igmp *igmp; 517 struct ip *ip; 518 struct ip_moptions imo; 519 #ifdef MROUTING 520 extern struct socket *ip_mrouter; 521 #endif /* MROUTING */ 522 523 MGETHDR(m, M_DONTWAIT, MT_HEADER); 524 if (m == NULL) 525 return; 526 /* 527 * Assume max_linkhdr + sizeof(struct ip) + IGMP_MINLEN 528 * is smaller than mbuf size returned by MGETHDR. 529 */ 530 m->m_data += max_linkhdr; 531 m->m_len = sizeof(struct ip) + IGMP_MINLEN; 532 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 533 534 ip = mtod(m, struct ip *); 535 ip->ip_tos = 0; 536 ip->ip_len = htons(sizeof(struct ip) + IGMP_MINLEN); 537 ip->ip_off = htons(0); 538 ip->ip_p = IPPROTO_IGMP; 539 ip->ip_src = zeroin_addr; 540 ip->ip_dst = inm->inm_addr; 541 542 m->m_data += sizeof(struct ip); 543 m->m_len -= sizeof(struct ip); 544 igmp = mtod(m, struct igmp *); 545 igmp->igmp_type = type; 546 igmp->igmp_code = 0; 547 igmp->igmp_group = inm->inm_addr; 548 igmp->igmp_cksum = 0; 549 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 550 m->m_data -= sizeof(struct ip); 551 m->m_len += sizeof(struct ip); 552 553 imo.imo_multicast_ifp = inm->inm_ifp; 554 imo.imo_multicast_ttl = 1; 555 #ifdef RSVP_ISI 556 imo.imo_multicast_vif = -1; 557 #endif 558 /* 559 * Request loopback of the report if we are acting as a multicast 560 * router, so that the process-level routing demon can hear it. 561 */ 562 #ifdef MROUTING 563 imo.imo_multicast_loop = (ip_mrouter != NULL); 564 #else 565 imo.imo_multicast_loop = 0; 566 #endif /* MROUTING */ 567 568 ip_output(m, (struct mbuf *)NULL, (struct route *)NULL, 569 IP_MULTICASTOPTS, &imo, (struct socket *)NULL); 570 571 ++igmpstat.igps_snd_reports; 572 } 573 574 void 575 igmp_purgeif(struct ifnet *ifp) 576 { 577 578 rti_delete(ifp); 579 }
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