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 */ 35 36 /* 37 * Internet Group Management Protocol (IGMP) routines. 38 * 39 * Written by Steve Deering, Stanford, May 1988. 40 * Modified by Rosen Sharma, Stanford, Aug 1994. 41 * Modified by Bill Fenner, Xerox PARC, Feb 1995. 42 * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995. 43 * 44 * MULTICAST Revision: 3.5.1.4 45 */ 46 47 #include <sys/cdefs.h> 48 __FBSDID("$FreeBSD$"); 49 50 #include "opt_mac.h" 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/malloc.h> 55 #include <sys/mbuf.h> 56 #include <sys/socket.h> 57 #include <sys/protosw.h> 58 #include <sys/kernel.h> 59 #include <sys/sysctl.h> 60 #include <sys/vimage.h> 61 62 #include <net/if.h> 63 #include <net/route.h> 64 65 #include <netinet/in.h> 66 #include <netinet/in_var.h> 67 #include <netinet/in_systm.h> 68 #include <netinet/ip.h> 69 #include <netinet/ip_var.h> 70 #include <netinet/ip_options.h> 71 #include <netinet/igmp.h> 72 #include <netinet/igmp_var.h> 73 74 #include <machine/in_cksum.h> 75 76 #include <security/mac/mac_framework.h> 77 78 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); 79 80 static struct router_info *find_rti(struct ifnet *ifp); 81 static void igmp_sendpkt(struct in_multi *, int, unsigned long); 82 83 static struct igmpstat igmpstat; 84 85 SYSCTL_V_STRUCT(V_NET, vnet_inet, _net_inet_igmp, IGMPCTL_STATS, 86 stats, CTLFLAG_RW, igmpstat, igmpstat, ""); 87 88 /* 89 * igmp_mtx protects all mutable global variables in igmp.c, as well as the 90 * data fields in struct router_info. In general, a router_info structure 91 * will be valid as long as the referencing struct in_multi is valid, so no 92 * reference counting is used. We allow unlocked reads of router_info data 93 * when accessed via an in_multi read-only. 94 */ 95 static struct mtx igmp_mtx; 96 static SLIST_HEAD(, router_info) router_info_head; 97 static int igmp_timers_are_running; 98 99 /* 100 * XXXRW: can we define these such that these can be made const? In any 101 * case, these shouldn't be changed after igmp_init() and therefore don't 102 * need locking. 103 */ 104 static u_long igmp_all_hosts_group; 105 static u_long igmp_all_rtrs_group; 106 107 static struct mbuf *router_alert; 108 static struct route igmprt; 109 110 #ifdef IGMP_DEBUG 111 #define IGMP_PRINTF(x) printf(x) 112 #else 113 #define IGMP_PRINTF(x) 114 #endif 115 116 void 117 igmp_init(void) 118 { 119 INIT_VNET_INET(curvnet); 120 struct ipoption *ra; 121 122 /* 123 * To avoid byte-swapping the same value over and over again. 124 */ 125 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 126 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 127 128 igmp_timers_are_running = 0; 129 130 /* 131 * Construct a Router Alert option to use in outgoing packets. 132 */ 133 MGET(router_alert, M_DONTWAIT, MT_DATA); 134 ra = mtod(router_alert, struct ipoption *); 135 ra->ipopt_dst.s_addr = 0; 136 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 137 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 138 ra->ipopt_list[2] = 0x00; 139 ra->ipopt_list[3] = 0x00; 140 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 141 142 mtx_init(&igmp_mtx, "igmp_mtx", NULL, MTX_DEF); 143 SLIST_INIT(&V_router_info_head); 144 } 145 146 static struct router_info * 147 find_rti(struct ifnet *ifp) 148 { 149 INIT_VNET_INET(ifp->if_vnet); 150 struct router_info *rti; 151 152 mtx_assert(&igmp_mtx, MA_OWNED); 153 IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n"); 154 SLIST_FOREACH(rti, &V_router_info_head, rti_list) { 155 if (rti->rti_ifp == ifp) { 156 IGMP_PRINTF( 157 "[igmp.c, _find_rti] --> found old entry \n"); 158 return (rti); 159 } 160 } 161 rti = malloc(sizeof *rti, M_IGMP, M_NOWAIT); 162 if (rti == NULL) { 163 IGMP_PRINTF("[igmp.c, _find_rti] --> no memory for entry\n"); 164 return (NULL); 165 } 166 rti->rti_ifp = ifp; 167 rti->rti_type = IGMP_V2_ROUTER; 168 rti->rti_time = 0; 169 SLIST_INSERT_HEAD(&V_router_info_head, rti, rti_list); 170 IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n"); 171 return (rti); 172 } 173 174 void 175 igmp_input(register struct mbuf *m, int off) 176 { 177 register int iphlen = off; 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 int timer; /** timer value in the igmp query header **/ 188 INIT_VNET_INET(ifp->if_vnet); 189 190 ++V_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 ++V_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 ++V_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 ++V_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; 228 229 /* 230 * In the IGMPv2 specification, there are 3 states and a flag. 231 * 232 * In Non-Member state, we simply don't have a membership record. 233 * In Delaying Member state, our timer is running (inm->inm_timer). 234 * In Idle Member state, our timer is not running (inm->inm_timer==0). 235 * 236 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if we 237 * have heard a report from another member, or IGMP_IREPORTEDLAST if 238 * I sent the last report. 239 */ 240 switch (igmp->igmp_type) { 241 case IGMP_MEMBERSHIP_QUERY: 242 ++V_igmpstat.igps_rcv_queries; 243 244 if (ifp->if_flags & IFF_LOOPBACK) 245 break; 246 247 if (igmp->igmp_code == 0) { 248 /* 249 * Old router. Remember that the querier on this 250 * interface is old, and set the timer to the value 251 * in RFC 1112. 252 */ 253 254 mtx_lock(&igmp_mtx); 255 rti = find_rti(ifp); 256 if (rti == NULL) { 257 mtx_unlock(&igmp_mtx); 258 m_freem(m); 259 return; 260 } 261 rti->rti_type = IGMP_V1_ROUTER; 262 rti->rti_time = 0; 263 mtx_unlock(&igmp_mtx); 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 ++V_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 ++V_igmpstat.igps_rcv_badqueries; 281 m_freem(m); 282 return; 283 } 284 } 285 286 /* 287 * - Start the timers in all of our membership records that 288 * the query applies to for the interface on which the 289 * query arrived excl. those that belong to the "all-hosts" 290 * group (224.0.0.1). 291 * - Restart any timer that is already running but has a 292 * value longer than the requested timeout. 293 * - Use the value specified in the query message as the 294 * maximum timeout. 295 */ 296 IN_MULTI_LOCK(); 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 IN_MULTI_UNLOCK(); 313 break; 314 315 case IGMP_V1_MEMBERSHIP_REPORT: 316 case IGMP_V2_MEMBERSHIP_REPORT: 317 /* 318 * For fast leave to work, we have to know that we are the 319 * last person to send a report for this group. Reports can 320 * potentially get looped back if we are a multicast router, 321 * so discard reports sourced by me. 322 */ 323 IFP_TO_IA(ifp, ia); 324 if (ia != NULL && 325 ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 326 break; 327 328 ++V_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 ++V_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 daemon 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 != NULL) 350 ip->ip_src.s_addr = htonl(ia->ia_subnet); 351 } 352 353 /* 354 * If we belong to the group being reported, stop our timer 355 * for that group. 356 */ 357 IN_MULTI_LOCK(); 358 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 359 if (inm != NULL) { 360 inm->inm_timer = 0; 361 ++V_igmpstat.igps_rcv_ourreports; 362 inm->inm_state = IGMP_OTHERMEMBER; 363 } 364 IN_MULTI_UNLOCK(); 365 break; 366 } 367 368 /* 369 * Pass all valid IGMP packets up to any process(es) listening on a 370 * raw IGMP socket. 371 */ 372 rip_input(m, off); 373 } 374 375 void 376 igmp_joingroup(struct in_multi *inm) 377 { 378 379 IN_MULTI_LOCK_ASSERT(); 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 mtx_lock(&igmp_mtx); 387 inm->inm_rti = find_rti(inm->inm_ifp); 388 mtx_unlock(&igmp_mtx); 389 if (inm->inm_rti != NULL) { 390 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 391 inm->inm_timer = IGMP_RANDOM_DELAY( 392 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 393 inm->inm_state = IGMP_IREPORTEDLAST; 394 igmp_timers_are_running = 1; 395 } 396 /* XXX handling of failure case? */ 397 } 398 } 399 400 void 401 igmp_leavegroup(struct in_multi *inm) 402 { 403 404 IN_MULTI_LOCK_ASSERT(); 405 406 if (inm->inm_state == IGMP_IREPORTEDLAST && 407 inm->inm_addr.s_addr != igmp_all_hosts_group && 408 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 409 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 410 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 411 } 412 413 void 414 igmp_fasttimo(void) 415 { 416 VNET_ITERATOR_DECL(vnet_iter); 417 register struct in_multi *inm; 418 struct in_multistep step; 419 420 /* 421 * Quick check to see if any work needs to be done, in order to 422 * minimize the overhead of fasttimo processing. 423 */ 424 425 if (!igmp_timers_are_running) 426 return; 427 428 IN_MULTI_LOCK(); 429 igmp_timers_are_running = 0; 430 VNET_LIST_RLOCK(); 431 VNET_FOREACH(vnet_iter) { 432 CURVNET_SET(vnet_iter); 433 INIT_VNET_INET(vnet_iter); 434 IN_FIRST_MULTI(step, inm); 435 while (inm != NULL) { 436 if (inm->inm_timer == 0) { 437 /* do nothing */ 438 } else if (--inm->inm_timer == 0) { 439 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 440 inm->inm_state = IGMP_IREPORTEDLAST; 441 } else { 442 igmp_timers_are_running = 1; 443 } 444 IN_NEXT_MULTI(step, inm); 445 } 446 CURVNET_RESTORE(); 447 } 448 VNET_LIST_RUNLOCK(); 449 IN_MULTI_UNLOCK(); 450 } 451 452 void 453 igmp_slowtimo(void) 454 { 455 VNET_ITERATOR_DECL(vnet_iter); 456 struct router_info *rti; 457 458 IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n"); 459 mtx_lock(&igmp_mtx); 460 VNET_LIST_RLOCK(); 461 VNET_FOREACH(vnet_iter) { 462 CURVNET_SET(vnet_iter); 463 INIT_VNET_INET(vnet_iter); 464 SLIST_FOREACH(rti, &V_router_info_head, rti_list) { 465 if (rti->rti_type == IGMP_V1_ROUTER) { 466 rti->rti_time++; 467 if (rti->rti_time >= IGMP_AGE_THRESHOLD) 468 rti->rti_type = IGMP_V2_ROUTER; 469 } 470 } 471 CURVNET_RESTORE(); 472 } 473 VNET_LIST_RUNLOCK(); 474 mtx_unlock(&igmp_mtx); 475 IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n"); 476 } 477 478 static void 479 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 480 { 481 INIT_VNET_NET(curvnet); 482 INIT_VNET_INET(curvnet); 483 struct mbuf *m; 484 struct igmp *igmp; 485 struct ip *ip; 486 struct ip_moptions imo; 487 488 IN_MULTI_LOCK_ASSERT(); 489 490 MGETHDR(m, M_DONTWAIT, MT_DATA); 491 if (m == NULL) 492 return; 493 494 m->m_pkthdr.rcvif = V_loif; 495 #ifdef MAC 496 mac_netinet_igmp_send(inm->inm_ifp, m); 497 #endif 498 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 499 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 500 m->m_data += sizeof(struct ip); 501 m->m_len = IGMP_MINLEN; 502 igmp = mtod(m, struct igmp *); 503 igmp->igmp_type = type; 504 igmp->igmp_code = 0; 505 igmp->igmp_group = inm->inm_addr; 506 igmp->igmp_cksum = 0; 507 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 508 509 m->m_data -= sizeof(struct ip); 510 m->m_len += sizeof(struct ip); 511 ip = mtod(m, struct ip *); 512 ip->ip_tos = 0; 513 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 514 ip->ip_off = 0; 515 ip->ip_p = IPPROTO_IGMP; 516 ip->ip_src.s_addr = INADDR_ANY; 517 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 518 519 imo.imo_multicast_ifp = inm->inm_ifp; 520 imo.imo_multicast_ttl = 1; 521 imo.imo_multicast_vif = -1; 522 /* 523 * Request loopback of the report if we are acting as a multicast 524 * router, so that the process-level routing daemon can hear it. 525 */ 526 imo.imo_multicast_loop = (V_ip_mrouter != NULL); 527 528 /* 529 * XXX: Do we have to worry about reentrancy here? Don't think so. 530 */ 531 ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 532 533 ++V_igmpstat.igps_snd_reports; 534 } 535