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/malloc.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/ip_options.h> 68 #include <netinet/igmp.h> 69 #include <netinet/igmp_var.h> 70 71 #include <machine/in_cksum.h> 72 73 #include <security/mac/mac_framework.h> 74 75 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); 76 77 static struct router_info *find_rti(struct ifnet *ifp); 78 static void igmp_sendpkt(struct in_multi *, int, unsigned long); 79 80 static struct igmpstat igmpstat; 81 82 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, &igmpstat, 83 igmpstat, ""); 84 85 /* 86 * igmp_mtx protects all mutable global variables in igmp.c, as well as the 87 * data fields in struct router_info. In general, a router_info structure 88 * will be valid as long as the referencing struct in_multi is valid, so no 89 * reference counting is used. We allow unlocked reads of router_info data 90 * when accessed via an in_multi read-only. 91 */ 92 static struct mtx igmp_mtx; 93 static SLIST_HEAD(, router_info) router_info_head; 94 static int igmp_timers_are_running; 95 96 /* 97 * XXXRW: can we define these such that these can be made const? In any 98 * case, these shouldn't be changed after igmp_init() and therefore don't 99 * need locking. 100 */ 101 static u_long igmp_all_hosts_group; 102 static u_long igmp_all_rtrs_group; 103 104 static struct mbuf *router_alert; 105 static struct route igmprt; 106 107 #ifdef IGMP_DEBUG 108 #define IGMP_PRINTF(x) printf(x) 109 #else 110 #define IGMP_PRINTF(x) 111 #endif 112 113 void 114 igmp_init(void) 115 { 116 struct ipoption *ra; 117 118 /* 119 * To avoid byte-swapping the same value over and over again. 120 */ 121 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 122 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 123 124 igmp_timers_are_running = 0; 125 126 /* 127 * Construct a Router Alert option to use in outgoing packets. 128 */ 129 MGET(router_alert, M_DONTWAIT, MT_DATA); 130 ra = mtod(router_alert, struct ipoption *); 131 ra->ipopt_dst.s_addr = 0; 132 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 133 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 134 ra->ipopt_list[2] = 0x00; 135 ra->ipopt_list[3] = 0x00; 136 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 137 138 mtx_init(&igmp_mtx, "igmp_mtx", NULL, MTX_DEF); 139 SLIST_INIT(&router_info_head); 140 } 141 142 static struct router_info * 143 find_rti(struct ifnet *ifp) 144 { 145 struct router_info *rti; 146 147 mtx_assert(&igmp_mtx, MA_OWNED); 148 IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n"); 149 SLIST_FOREACH(rti, &router_info_head, rti_list) { 150 if (rti->rti_ifp == ifp) { 151 IGMP_PRINTF( 152 "[igmp.c, _find_rti] --> found old entry \n"); 153 return (rti); 154 } 155 } 156 MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT); 157 if (rti == NULL) { 158 IGMP_PRINTF("[igmp.c, _find_rti] --> no memory for entry\n"); 159 return (NULL); 160 } 161 rti->rti_ifp = ifp; 162 rti->rti_type = IGMP_V2_ROUTER; 163 rti->rti_time = 0; 164 SLIST_INSERT_HEAD(&router_info_head, rti, rti_list); 165 IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n"); 166 return (rti); 167 } 168 169 void 170 igmp_input(register struct mbuf *m, int off) 171 { 172 register int iphlen = off; 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 int timer; /** timer value in the igmp query header **/ 183 184 ++igmpstat.igps_rcv_total; 185 186 ip = mtod(m, struct ip *); 187 igmplen = ip->ip_len; 188 189 /* 190 * Validate lengths. 191 */ 192 if (igmplen < IGMP_MINLEN) { 193 ++igmpstat.igps_rcv_tooshort; 194 m_freem(m); 195 return; 196 } 197 minlen = iphlen + IGMP_MINLEN; 198 if ((m->m_flags & M_EXT || m->m_len < minlen) && 199 (m = m_pullup(m, minlen)) == 0) { 200 ++igmpstat.igps_rcv_tooshort; 201 return; 202 } 203 204 /* 205 * Validate checksum. 206 */ 207 m->m_data += iphlen; 208 m->m_len -= iphlen; 209 igmp = mtod(m, struct igmp *); 210 if (in_cksum(m, igmplen)) { 211 ++igmpstat.igps_rcv_badsum; 212 m_freem(m); 213 return; 214 } 215 m->m_data -= iphlen; 216 m->m_len += iphlen; 217 218 ip = mtod(m, struct ip *); 219 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 220 if (timer == 0) 221 timer = 1; 222 223 /* 224 * In the IGMPv2 specification, there are 3 states and a flag. 225 * 226 * In Non-Member state, we simply don't have a membership record. 227 * In Delaying Member state, our timer is running (inm->inm_timer). 228 * In Idle Member state, our timer is not running (inm->inm_timer==0). 229 * 230 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if we 231 * have heard a report from another member, or IGMP_IREPORTEDLAST if 232 * I sent the last report. 233 */ 234 switch (igmp->igmp_type) { 235 case IGMP_MEMBERSHIP_QUERY: 236 ++igmpstat.igps_rcv_queries; 237 238 if (ifp->if_flags & IFF_LOOPBACK) 239 break; 240 241 if (igmp->igmp_code == 0) { 242 /* 243 * Old router. Remember that the querier on this 244 * interface is old, and set the timer to the value 245 * in RFC 1112. 246 */ 247 248 mtx_lock(&igmp_mtx); 249 rti = find_rti(ifp); 250 if (rti == NULL) { 251 mtx_unlock(&igmp_mtx); 252 m_freem(m); 253 return; 254 } 255 rti->rti_type = IGMP_V1_ROUTER; 256 rti->rti_time = 0; 257 mtx_unlock(&igmp_mtx); 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 that 282 * the query applies to for the interface on which the 283 * query arrived excl. those that belong to the "all-hosts" 284 * group (224.0.0.1). 285 * - Restart any timer that is already running but has a 286 * value longer than the requested timeout. 287 * - Use the value specified in the query message as the 288 * maximum timeout. 289 */ 290 IN_MULTI_LOCK(); 291 IN_FIRST_MULTI(step, inm); 292 while (inm != NULL) { 293 if (inm->inm_ifp == ifp && 294 inm->inm_addr.s_addr != igmp_all_hosts_group && 295 (igmp->igmp_group.s_addr == 0 || 296 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 297 if (inm->inm_timer == 0 || 298 inm->inm_timer > timer) { 299 inm->inm_timer = 300 IGMP_RANDOM_DELAY(timer); 301 igmp_timers_are_running = 1; 302 } 303 } 304 IN_NEXT_MULTI(step, inm); 305 } 306 IN_MULTI_UNLOCK(); 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 can 314 * potentially get looped back if we are a multicast router, 315 * so discard reports sourced by me. 316 */ 317 IFP_TO_IA(ifp, ia); 318 if (ia != NULL && 319 ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 320 break; 321 322 ++igmpstat.igps_rcv_reports; 323 324 if (ifp->if_flags & IFF_LOOPBACK) 325 break; 326 327 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 328 ++igmpstat.igps_rcv_badreports; 329 m_freem(m); 330 return; 331 } 332 333 /* 334 * KLUDGE: if the IP source address of the report has an 335 * unspecified (i.e., zero) subnet number, as is allowed for 336 * a booting host, replace it with the correct subnet number 337 * so that a process-level multicast routing daemon can 338 * determine which subnet it arrived from. This is necessary 339 * to compensate for the lack of any way for a process to 340 * determine the arrival interface of an incoming packet. 341 */ 342 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) { 343 if (ia != NULL) 344 ip->ip_src.s_addr = htonl(ia->ia_subnet); 345 } 346 347 /* 348 * If we belong to the group being reported, stop our timer 349 * for that group. 350 */ 351 IN_MULTI_LOCK(); 352 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 353 if (inm != NULL) { 354 inm->inm_timer = 0; 355 ++igmpstat.igps_rcv_ourreports; 356 inm->inm_state = IGMP_OTHERMEMBER; 357 } 358 IN_MULTI_UNLOCK(); 359 break; 360 } 361 362 /* 363 * Pass all valid IGMP packets up to any process(es) listening on a 364 * raw IGMP socket. 365 */ 366 rip_input(m, off); 367 } 368 369 void 370 igmp_joingroup(struct in_multi *inm) 371 { 372 373 IN_MULTI_LOCK_ASSERT(); 374 375 if (inm->inm_addr.s_addr == igmp_all_hosts_group 376 || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 377 inm->inm_timer = 0; 378 inm->inm_state = IGMP_OTHERMEMBER; 379 } else { 380 mtx_lock(&igmp_mtx); 381 inm->inm_rti = find_rti(inm->inm_ifp); 382 mtx_unlock(&igmp_mtx); 383 if (inm->inm_rti != NULL) { 384 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 385 inm->inm_timer = IGMP_RANDOM_DELAY( 386 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 387 inm->inm_state = IGMP_IREPORTEDLAST; 388 igmp_timers_are_running = 1; 389 } 390 /* XXX handling of failure case? */ 391 } 392 } 393 394 void 395 igmp_leavegroup(struct in_multi *inm) 396 { 397 398 IN_MULTI_LOCK_ASSERT(); 399 400 if (inm->inm_state == IGMP_IREPORTEDLAST && 401 inm->inm_addr.s_addr != igmp_all_hosts_group && 402 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 403 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 404 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 405 } 406 407 void 408 igmp_fasttimo(void) 409 { 410 register struct in_multi *inm; 411 struct in_multistep step; 412 413 /* 414 * Quick check to see if any work needs to be done, in order to 415 * minimize the overhead of fasttimo processing. 416 */ 417 418 if (!igmp_timers_are_running) 419 return; 420 421 IN_MULTI_LOCK(); 422 igmp_timers_are_running = 0; 423 IN_FIRST_MULTI(step, inm); 424 while (inm != NULL) { 425 if (inm->inm_timer == 0) { 426 /* do nothing */ 427 } else if (--inm->inm_timer == 0) { 428 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 429 inm->inm_state = IGMP_IREPORTEDLAST; 430 } else { 431 igmp_timers_are_running = 1; 432 } 433 IN_NEXT_MULTI(step, inm); 434 } 435 IN_MULTI_UNLOCK(); 436 } 437 438 void 439 igmp_slowtimo(void) 440 { 441 struct router_info *rti; 442 443 IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n"); 444 mtx_lock(&igmp_mtx); 445 SLIST_FOREACH(rti, &router_info_head, rti_list) { 446 if (rti->rti_type == IGMP_V1_ROUTER) { 447 rti->rti_time++; 448 if (rti->rti_time >= IGMP_AGE_THRESHOLD) 449 rti->rti_type = IGMP_V2_ROUTER; 450 } 451 } 452 mtx_unlock(&igmp_mtx); 453 IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n"); 454 } 455 456 static void 457 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 458 { 459 struct mbuf *m; 460 struct igmp *igmp; 461 struct ip *ip; 462 struct ip_moptions imo; 463 464 IN_MULTI_LOCK_ASSERT(); 465 466 MGETHDR(m, M_DONTWAIT, MT_DATA); 467 if (m == NULL) 468 return; 469 470 m->m_pkthdr.rcvif = loif; 471 #ifdef MAC 472 mac_create_mbuf_linklayer(inm->inm_ifp, m); 473 #endif 474 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 475 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 476 m->m_data += sizeof(struct ip); 477 m->m_len = IGMP_MINLEN; 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 daemon can hear it. 501 */ 502 imo.imo_multicast_loop = (ip_mrouter != NULL); 503 504 /* 505 * XXX: 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