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 * 4. 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 * $FreeBSD$ 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 "opt_mac.h" 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/mac.h> 53 #include <sys/malloc.h> 54 #include <sys/mbuf.h> 55 #include <sys/socket.h> 56 #include <sys/protosw.h> 57 #include <sys/kernel.h> 58 #include <sys/sysctl.h> 59 60 #include <net/if.h> 61 #include <net/route.h> 62 63 #include <netinet/in.h> 64 #include <netinet/in_var.h> 65 #include <netinet/in_systm.h> 66 #include <netinet/ip.h> 67 #include <netinet/ip_var.h> 68 #include <netinet/igmp.h> 69 #include <netinet/igmp_var.h> 70 71 #include <machine/in_cksum.h> 72 73 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); 74 75 static struct router_info *find_rti(struct ifnet *ifp); 76 static void igmp_sendpkt(struct in_multi *, int, unsigned long); 77 78 static struct igmpstat igmpstat; 79 80 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, &igmpstat, 81 igmpstat, ""); 82 83 /* 84 * igmp_mtx protects all mutable global variables in igmp.c, as well as 85 * the data fields in struct router_info. In general, a router_info 86 * structure will be valid as long as the referencing struct in_multi is 87 * valid, so no reference counting is used. We allow unlocked reads of 88 * router_info data when accessed via an in_multi read-only. 89 */ 90 static struct mtx igmp_mtx; 91 static SLIST_HEAD(, router_info) router_info_head; 92 static int igmp_timers_are_running; 93 94 /* 95 * XXXRW: can we define these such that these can be made const? In any 96 * case, these shouldn't be changed after igmp_init() and therefore don't 97 * need locking. 98 */ 99 static u_long igmp_all_hosts_group; 100 static u_long igmp_all_rtrs_group; 101 102 static struct mbuf *router_alert; 103 static struct route igmprt; 104 105 #ifdef IGMP_DEBUG 106 #define IGMP_PRINTF(x) printf(x) 107 #else 108 #define IGMP_PRINTF(x) 109 #endif 110 111 void 112 igmp_init(void) 113 { 114 struct ipoption *ra; 115 116 /* 117 * To avoid byte-swapping the same value over and over again. 118 */ 119 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 120 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 121 122 igmp_timers_are_running = 0; 123 124 /* 125 * Construct a Router Alert option to use in outgoing packets 126 */ 127 MGET(router_alert, M_DONTWAIT, MT_DATA); 128 ra = mtod(router_alert, struct ipoption *); 129 ra->ipopt_dst.s_addr = 0; 130 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 131 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 132 ra->ipopt_list[2] = 0x00; 133 ra->ipopt_list[3] = 0x00; 134 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 135 136 mtx_init(&igmp_mtx, "igmp_mtx", NULL, MTX_DEF); 137 SLIST_INIT(&router_info_head); 138 } 139 140 static struct router_info * 141 find_rti(struct ifnet *ifp) 142 { 143 struct router_info *rti; 144 145 mtx_assert(&igmp_mtx, MA_OWNED); 146 IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n"); 147 SLIST_FOREACH(rti, &router_info_head, rti_list) { 148 if (rti->rti_ifp == ifp) { 149 IGMP_PRINTF( 150 "[igmp.c, _find_rti] --> found old entry \n"); 151 return rti; 152 } 153 } 154 MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT); 155 if (rti == NULL) { 156 IGMP_PRINTF( "[igmp.c, _find_rti] --> no memory for entry\n"); 157 return NULL; 158 } 159 rti->rti_ifp = ifp; 160 rti->rti_type = IGMP_V2_ROUTER; 161 rti->rti_time = 0; 162 SLIST_INSERT_HEAD(&router_info_head, rti, rti_list); 163 164 IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n"); 165 return rti; 166 } 167 168 void 169 igmp_input(register struct mbuf *m, int off) 170 { 171 register int iphlen = off; 172 register struct igmp *igmp; 173 register struct ip *ip; 174 register int igmplen; 175 register struct ifnet *ifp = m->m_pkthdr.rcvif; 176 register int minlen; 177 register struct in_multi *inm; 178 register struct in_ifaddr *ia; 179 struct in_multistep step; 180 struct router_info *rti; 181 int timer; /** timer value in the igmp query header **/ 182 183 ++igmpstat.igps_rcv_total; 184 185 ip = mtod(m, struct ip *); 186 igmplen = ip->ip_len; 187 188 /* 189 * Validate lengths 190 */ 191 if (igmplen < IGMP_MINLEN) { 192 ++igmpstat.igps_rcv_tooshort; 193 m_freem(m); 194 return; 195 } 196 minlen = iphlen + IGMP_MINLEN; 197 if ((m->m_flags & M_EXT || m->m_len < minlen) && 198 (m = m_pullup(m, minlen)) == 0) { 199 ++igmpstat.igps_rcv_tooshort; 200 return; 201 } 202 203 /* 204 * Validate checksum 205 */ 206 m->m_data += iphlen; 207 m->m_len -= iphlen; 208 igmp = mtod(m, struct igmp *); 209 if (in_cksum(m, igmplen)) { 210 ++igmpstat.igps_rcv_badsum; 211 m_freem(m); 212 return; 213 } 214 m->m_data -= iphlen; 215 m->m_len += iphlen; 216 217 ip = mtod(m, struct ip *); 218 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 219 if (timer == 0) 220 timer = 1; 221 222 /* 223 * In the IGMPv2 specification, there are 3 states and a flag. 224 * 225 * In Non-Member state, we simply don't have a membership record. 226 * In Delaying Member state, our timer is running (inm->inm_timer) 227 * In Idle Member state, our timer is not running (inm->inm_timer==0) 228 * 229 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 230 * we have heard a report from another member, or IGMP_IREPORTEDLAST 231 * if I sent the last report. 232 */ 233 switch (igmp->igmp_type) { 234 case IGMP_MEMBERSHIP_QUERY: 235 ++igmpstat.igps_rcv_queries; 236 237 if (ifp->if_flags & IFF_LOOPBACK) 238 break; 239 240 if (igmp->igmp_code == 0) { 241 /* 242 * Old router. Remember that the querier on this 243 * interface is old, and set the timer to the 244 * value in RFC 1112. 245 */ 246 247 mtx_lock(&igmp_mtx); 248 rti = find_rti(ifp); 249 if (rti == NULL) { 250 mtx_unlock(&igmp_mtx); 251 m_freem(m); 252 return; 253 } 254 rti->rti_type = IGMP_V1_ROUTER; 255 rti->rti_time = 0; 256 mtx_unlock(&igmp_mtx); 257 258 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 259 260 if (ip->ip_dst.s_addr != igmp_all_hosts_group || 261 igmp->igmp_group.s_addr != 0) { 262 ++igmpstat.igps_rcv_badqueries; 263 m_freem(m); 264 return; 265 } 266 } else { 267 /* 268 * New router. Simply do the new validity check. 269 */ 270 271 if (igmp->igmp_group.s_addr != 0 && 272 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 273 ++igmpstat.igps_rcv_badqueries; 274 m_freem(m); 275 return; 276 } 277 } 278 279 /* 280 * - Start the timers in all of our membership records 281 * that the query applies to for the interface on 282 * which the query arrived excl. those that belong 283 * to the "all-hosts" group (224.0.0.1). 284 * - Restart any timer that is already running but has 285 * a value longer than the requested timeout. 286 * - Use the value specified in the query message as 287 * the maximum timeout. 288 */ 289 IN_MULTI_LOCK(); 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 IN_MULTI_UNLOCK(); 306 307 break; 308 309 case IGMP_V1_MEMBERSHIP_REPORT: 310 case IGMP_V2_MEMBERSHIP_REPORT: 311 /* 312 * For fast leave to work, we have to know that we are the 313 * last person to send a report for this group. Reports 314 * can potentially get looped back if we are a multicast 315 * router, so discard reports sourced by me. 316 */ 317 IFP_TO_IA(ifp, ia); 318 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 319 break; 320 321 ++igmpstat.igps_rcv_reports; 322 323 if (ifp->if_flags & IFF_LOOPBACK) 324 break; 325 326 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 327 ++igmpstat.igps_rcv_badreports; 328 m_freem(m); 329 return; 330 } 331 332 /* 333 * KLUDGE: if the IP source address of the report has an 334 * unspecified (i.e., zero) subnet number, as is allowed for 335 * a booting host, replace it with the correct subnet number 336 * so that a process-level multicast routing daemon can 337 * determine which subnet it arrived from. This is necessary 338 * to compensate for the lack of any way for a process to 339 * determine the arrival interface of an incoming packet. 340 */ 341 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 342 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 343 344 /* 345 * If we belong to the group being reported, stop 346 * our timer for that group. 347 */ 348 IN_MULTI_LOCK(); 349 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 350 if (inm != NULL) { 351 inm->inm_timer = 0; 352 ++igmpstat.igps_rcv_ourreports; 353 354 inm->inm_state = IGMP_OTHERMEMBER; 355 } 356 IN_MULTI_UNLOCK(); 357 358 break; 359 } 360 361 /* 362 * Pass all valid IGMP packets up to any process(es) listening 363 * on a raw IGMP socket. 364 */ 365 rip_input(m, off); 366 } 367 368 void 369 igmp_joingroup(struct in_multi *inm) 370 { 371 372 IN_MULTI_LOCK_ASSERT(); 373 374 if (inm->inm_addr.s_addr == igmp_all_hosts_group 375 || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 376 inm->inm_timer = 0; 377 inm->inm_state = IGMP_OTHERMEMBER; 378 } else { 379 mtx_lock(&igmp_mtx); 380 inm->inm_rti = find_rti(inm->inm_ifp); 381 mtx_unlock(&igmp_mtx); 382 if (inm->inm_rti != NULL) { 383 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 384 inm->inm_timer = IGMP_RANDOM_DELAY( 385 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 386 inm->inm_state = IGMP_IREPORTEDLAST; 387 igmp_timers_are_running = 1; 388 } 389 /* XXX handling of failure case? */ 390 } 391 } 392 393 void 394 igmp_leavegroup(struct in_multi *inm) 395 { 396 397 IN_MULTI_LOCK_ASSERT(); 398 399 if (inm->inm_state == IGMP_IREPORTEDLAST && 400 inm->inm_addr.s_addr != igmp_all_hosts_group && 401 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 402 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 403 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 404 } 405 406 void 407 igmp_fasttimo(void) 408 { 409 register struct in_multi *inm; 410 struct in_multistep step; 411 412 /* 413 * Quick check to see if any work needs to be done, in order 414 * to minimize the overhead of fasttimo processing. 415 */ 416 417 if (!igmp_timers_are_running) 418 return; 419 420 IN_MULTI_LOCK(); 421 igmp_timers_are_running = 0; 422 IN_FIRST_MULTI(step, inm); 423 while (inm != NULL) { 424 if (inm->inm_timer == 0) { 425 /* do nothing */ 426 } else if (--inm->inm_timer == 0) { 427 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 428 inm->inm_state = IGMP_IREPORTEDLAST; 429 } else { 430 igmp_timers_are_running = 1; 431 } 432 IN_NEXT_MULTI(step, inm); 433 } 434 IN_MULTI_UNLOCK(); 435 } 436 437 void 438 igmp_slowtimo(void) 439 { 440 struct router_info *rti; 441 442 IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n"); 443 mtx_lock(&igmp_mtx); 444 SLIST_FOREACH(rti, &router_info_head, rti_list) { 445 if (rti->rti_type == IGMP_V1_ROUTER) { 446 rti->rti_time++; 447 if (rti->rti_time >= IGMP_AGE_THRESHOLD) 448 rti->rti_type = IGMP_V2_ROUTER; 449 } 450 } 451 mtx_unlock(&igmp_mtx); 452 IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n"); 453 } 454 455 static void 456 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 457 { 458 struct mbuf *m; 459 struct igmp *igmp; 460 struct ip *ip; 461 struct ip_moptions imo; 462 463 IN_MULTI_LOCK_ASSERT(); 464 465 MGETHDR(m, M_DONTWAIT, MT_HEADER); 466 if (m == NULL) 467 return; 468 469 m->m_pkthdr.rcvif = loif; 470 #ifdef MAC 471 mac_create_mbuf_linklayer(inm->inm_ifp, m); 472 #endif 473 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 474 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 475 m->m_data += sizeof(struct ip); 476 m->m_len = IGMP_MINLEN; 477 igmp = mtod(m, struct igmp *); 478 igmp->igmp_type = type; 479 igmp->igmp_code = 0; 480 igmp->igmp_group = inm->inm_addr; 481 igmp->igmp_cksum = 0; 482 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 483 484 m->m_data -= sizeof(struct ip); 485 m->m_len += sizeof(struct ip); 486 ip = mtod(m, struct ip *); 487 ip->ip_tos = 0; 488 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 489 ip->ip_off = 0; 490 ip->ip_p = IPPROTO_IGMP; 491 ip->ip_src.s_addr = INADDR_ANY; 492 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 493 494 imo.imo_multicast_ifp = inm->inm_ifp; 495 imo.imo_multicast_ttl = 1; 496 imo.imo_multicast_vif = -1; 497 /* 498 * Request loopback of the report if we are acting as a multicast 499 * router, so that the process-level routing daemon can hear it. 500 */ 501 imo.imo_multicast_loop = (ip_mrouter != NULL); 502 503 /* 504 * XXX 505 * Do we have to worry about reentrancy here? Don't think so. 506 */ 507 ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 508 509 ++igmpstat.igps_snd_reports; 510 } 511