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 * $FreeBSD: src/sys/netinet/igmp.c,v 1.29.2.2 2003/01/23 21:06:44 sam Exp $ 39 * $DragonFly: src/sys/netinet/igmp.c,v 1.6 2004/02/14 21:12:39 dillon Exp $ 40 */ 41 42 /* 43 * Internet Group Management Protocol (IGMP) routines. 44 * 45 * Written by Steve Deering, Stanford, May 1988. 46 * Modified by Rosen Sharma, Stanford, Aug 1994. 47 * Modified by Bill Fenner, Xerox PARC, Feb 1995. 48 * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995. 49 * 50 * MULTICAST Revision: 3.5.1.4 51 */ 52 53 #include <sys/param.h> 54 #include <sys/systm.h> 55 #include <sys/malloc.h> 56 #include <sys/mbuf.h> 57 #include <sys/socket.h> 58 #include <sys/protosw.h> 59 #include <sys/kernel.h> 60 #include <sys/sysctl.h> 61 #include <sys/in_cksum.h> 62 63 #include <net/if.h> 64 #include <net/route.h> 65 66 #include <netinet/in.h> 67 #include <netinet/in_var.h> 68 #include <netinet/in_systm.h> 69 #include <netinet/ip.h> 70 #include <netinet/ip_var.h> 71 #include <netinet/igmp.h> 72 #include <netinet/igmp_var.h> 73 74 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); 75 76 static struct router_info * 77 find_rti (struct ifnet *ifp); 78 79 static struct igmpstat igmpstat; 80 81 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, 82 &igmpstat, igmpstat, ""); 83 84 static int igmp_timers_are_running; 85 static u_long igmp_all_hosts_group; 86 static u_long igmp_all_rtrs_group; 87 static struct mbuf *router_alert; 88 static struct router_info *Head; 89 90 static void igmp_sendpkt (struct in_multi *, int, unsigned long); 91 92 void 93 igmp_init() 94 { 95 struct ipoption *ra; 96 97 /* 98 * To avoid byte-swapping the same value over and over again. 99 */ 100 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 101 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 102 103 igmp_timers_are_running = 0; 104 105 /* 106 * Construct a Router Alert option to use in outgoing packets 107 */ 108 MGET(router_alert, M_DONTWAIT, MT_DATA); 109 ra = mtod(router_alert, struct ipoption *); 110 ra->ipopt_dst.s_addr = 0; 111 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 112 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 113 ra->ipopt_list[2] = 0x00; 114 ra->ipopt_list[3] = 0x00; 115 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 116 117 Head = (struct router_info *) 0; 118 } 119 120 static struct router_info * 121 find_rti(ifp) 122 struct ifnet *ifp; 123 { 124 struct router_info *rti = Head; 125 126 #ifdef IGMP_DEBUG 127 printf("[igmp.c, _find_rti] --> entering \n"); 128 #endif 129 while (rti) { 130 if (rti->rti_ifp == ifp) { 131 #ifdef IGMP_DEBUG 132 printf("[igmp.c, _find_rti] --> found old entry \n"); 133 #endif 134 return rti; 135 } 136 rti = rti->rti_next; 137 } 138 MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT); 139 rti->rti_ifp = ifp; 140 rti->rti_type = IGMP_V2_ROUTER; 141 rti->rti_time = 0; 142 rti->rti_next = Head; 143 Head = rti; 144 #ifdef IGMP_DEBUG 145 printf("[igmp.c, _find_rti] --> created an entry \n"); 146 #endif 147 return rti; 148 } 149 150 void 151 igmp_input(m, off, proto) 152 struct mbuf *m; 153 int off, proto; 154 { 155 int iphlen = off; 156 struct igmp *igmp; 157 struct ip *ip; 158 int igmplen; 159 struct ifnet *ifp = m->m_pkthdr.rcvif; 160 int minlen; 161 struct in_multi *inm; 162 struct in_ifaddr *ia; 163 struct in_multistep step; 164 struct router_info *rti; 165 166 int timer; /** timer value in the igmp query header **/ 167 168 ++igmpstat.igps_rcv_total; 169 170 ip = mtod(m, struct ip *); 171 igmplen = ip->ip_len; 172 173 /* 174 * Validate lengths 175 */ 176 if (igmplen < IGMP_MINLEN) { 177 ++igmpstat.igps_rcv_tooshort; 178 m_freem(m); 179 return; 180 } 181 minlen = iphlen + IGMP_MINLEN; 182 if ((m->m_flags & M_EXT || m->m_len < minlen) && 183 (m = m_pullup(m, minlen)) == 0) { 184 ++igmpstat.igps_rcv_tooshort; 185 return; 186 } 187 188 /* 189 * Validate checksum 190 */ 191 m->m_data += iphlen; 192 m->m_len -= iphlen; 193 igmp = mtod(m, struct igmp *); 194 if (in_cksum(m, igmplen)) { 195 ++igmpstat.igps_rcv_badsum; 196 m_freem(m); 197 return; 198 } 199 m->m_data -= iphlen; 200 m->m_len += iphlen; 201 202 ip = mtod(m, struct ip *); 203 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 204 if (timer == 0) 205 timer = 1; 206 rti = find_rti(ifp); 207 208 /* 209 * In the IGMPv2 specification, there are 3 states and a flag. 210 * 211 * In Non-Member state, we simply don't have a membership record. 212 * In Delaying Member state, our timer is running (inm->inm_timer) 213 * In Idle Member state, our timer is not running (inm->inm_timer==0) 214 * 215 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 216 * we have heard a report from another member, or IGMP_IREPORTEDLAST 217 * if I sent the last report. 218 */ 219 switch (igmp->igmp_type) { 220 221 case IGMP_MEMBERSHIP_QUERY: 222 ++igmpstat.igps_rcv_queries; 223 224 if (ifp->if_flags & IFF_LOOPBACK) 225 break; 226 227 if (igmp->igmp_code == 0) { 228 /* 229 * Old router. Remember that the querier on this 230 * interface is old, and set the timer to the 231 * value in RFC 1112. 232 */ 233 234 rti->rti_type = IGMP_V1_ROUTER; 235 rti->rti_time = 0; 236 237 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 238 239 if (ip->ip_dst.s_addr != igmp_all_hosts_group || 240 igmp->igmp_group.s_addr != 0) { 241 ++igmpstat.igps_rcv_badqueries; 242 m_freem(m); 243 return; 244 } 245 } else { 246 /* 247 * New router. Simply do the new validity check. 248 */ 249 250 if (igmp->igmp_group.s_addr != 0 && 251 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 252 ++igmpstat.igps_rcv_badqueries; 253 m_freem(m); 254 return; 255 } 256 } 257 258 /* 259 * - Start the timers in all of our membership records 260 * that the query applies to for the interface on 261 * which the query arrived excl. those that belong 262 * to the "all-hosts" group (224.0.0.1). 263 * - Restart any timer that is already running but has 264 * a value longer than the requested timeout. 265 * - Use the value specified in the query message as 266 * the maximum timeout. 267 */ 268 IN_FIRST_MULTI(step, inm); 269 while (inm != NULL) { 270 if (inm->inm_ifp == ifp && 271 inm->inm_addr.s_addr != igmp_all_hosts_group && 272 (igmp->igmp_group.s_addr == 0 || 273 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 274 if (inm->inm_timer == 0 || 275 inm->inm_timer > timer) { 276 inm->inm_timer = 277 IGMP_RANDOM_DELAY(timer); 278 igmp_timers_are_running = 1; 279 } 280 } 281 IN_NEXT_MULTI(step, inm); 282 } 283 284 break; 285 286 case IGMP_V1_MEMBERSHIP_REPORT: 287 case IGMP_V2_MEMBERSHIP_REPORT: 288 /* 289 * For fast leave to work, we have to know that we are the 290 * last person to send a report for this group. Reports 291 * can potentially get looped back if we are a multicast 292 * router, so discard reports sourced by me. 293 */ 294 IFP_TO_IA(ifp, ia); 295 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 296 break; 297 298 ++igmpstat.igps_rcv_reports; 299 300 if (ifp->if_flags & IFF_LOOPBACK) 301 break; 302 303 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 304 ++igmpstat.igps_rcv_badreports; 305 m_freem(m); 306 return; 307 } 308 309 /* 310 * KLUDGE: if the IP source address of the report has an 311 * unspecified (i.e., zero) subnet number, as is allowed for 312 * a booting host, replace it with the correct subnet number 313 * so that a process-level multicast routing demon can 314 * determine which subnet it arrived from. This is necessary 315 * to compensate for the lack of any way for a process to 316 * determine the arrival interface of an incoming packet. 317 */ 318 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 319 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 320 321 /* 322 * If we belong to the group being reported, stop 323 * our timer for that group. 324 */ 325 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 326 327 if (inm != NULL) { 328 inm->inm_timer = 0; 329 ++igmpstat.igps_rcv_ourreports; 330 331 inm->inm_state = IGMP_OTHERMEMBER; 332 } 333 334 break; 335 } 336 337 /* 338 * Pass all valid IGMP packets up to any process(es) listening 339 * on a raw IGMP socket. 340 */ 341 rip_input(m, off, proto); 342 } 343 344 void 345 igmp_joingroup(inm) 346 struct in_multi *inm; 347 { 348 int s = splnet(); 349 350 if (inm->inm_addr.s_addr == igmp_all_hosts_group 351 || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 352 inm->inm_timer = 0; 353 inm->inm_state = IGMP_OTHERMEMBER; 354 } else { 355 inm->inm_rti = find_rti(inm->inm_ifp); 356 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 357 inm->inm_timer = IGMP_RANDOM_DELAY( 358 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 359 inm->inm_state = IGMP_IREPORTEDLAST; 360 igmp_timers_are_running = 1; 361 } 362 splx(s); 363 } 364 365 void 366 igmp_leavegroup(inm) 367 struct in_multi *inm; 368 { 369 if (inm->inm_state == IGMP_IREPORTEDLAST && 370 inm->inm_addr.s_addr != igmp_all_hosts_group && 371 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 372 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 373 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 374 } 375 376 void 377 igmp_fasttimo() 378 { 379 struct in_multi *inm; 380 struct in_multistep step; 381 int s; 382 383 /* 384 * Quick check to see if any work needs to be done, in order 385 * to minimize the overhead of fasttimo processing. 386 */ 387 388 if (!igmp_timers_are_running) 389 return; 390 391 s = splnet(); 392 igmp_timers_are_running = 0; 393 IN_FIRST_MULTI(step, inm); 394 while (inm != NULL) { 395 if (inm->inm_timer == 0) { 396 /* do nothing */ 397 } else if (--inm->inm_timer == 0) { 398 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 399 inm->inm_state = IGMP_IREPORTEDLAST; 400 } else { 401 igmp_timers_are_running = 1; 402 } 403 IN_NEXT_MULTI(step, inm); 404 } 405 splx(s); 406 } 407 408 void 409 igmp_slowtimo() 410 { 411 int s = splnet(); 412 struct router_info *rti = Head; 413 414 #ifdef IGMP_DEBUG 415 printf("[igmp.c,_slowtimo] -- > entering \n"); 416 #endif 417 while (rti) { 418 if (rti->rti_type == IGMP_V1_ROUTER) { 419 rti->rti_time++; 420 if (rti->rti_time >= IGMP_AGE_THRESHOLD) { 421 rti->rti_type = IGMP_V2_ROUTER; 422 } 423 } 424 rti = rti->rti_next; 425 } 426 #ifdef IGMP_DEBUG 427 printf("[igmp.c,_slowtimo] -- > exiting \n"); 428 #endif 429 splx(s); 430 } 431 432 static struct route igmprt; 433 434 static void 435 igmp_sendpkt(inm, type, addr) 436 struct in_multi *inm; 437 int type; 438 unsigned long addr; 439 { 440 struct mbuf *m; 441 struct igmp *igmp; 442 struct ip *ip; 443 struct ip_moptions imo; 444 445 MGETHDR(m, M_DONTWAIT, MT_HEADER); 446 if (m == NULL) 447 return; 448 449 m->m_pkthdr.rcvif = loif; 450 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 451 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 452 m->m_data += sizeof(struct ip); 453 m->m_len = IGMP_MINLEN; 454 igmp = mtod(m, struct igmp *); 455 igmp->igmp_type = type; 456 igmp->igmp_code = 0; 457 igmp->igmp_group = inm->inm_addr; 458 igmp->igmp_cksum = 0; 459 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 460 461 m->m_data -= sizeof(struct ip); 462 m->m_len += sizeof(struct ip); 463 ip = mtod(m, struct ip *); 464 ip->ip_tos = 0; 465 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 466 ip->ip_off = 0; 467 ip->ip_p = IPPROTO_IGMP; 468 ip->ip_src.s_addr = INADDR_ANY; 469 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 470 471 imo.imo_multicast_ifp = inm->inm_ifp; 472 imo.imo_multicast_ttl = 1; 473 imo.imo_multicast_vif = -1; 474 /* 475 * Request loopback of the report if we are acting as a multicast 476 * router, so that the process-level routing demon can hear it. 477 */ 478 imo.imo_multicast_loop = (ip_mrouter != NULL); 479 480 /* 481 * XXX 482 * Do we have to worry about reentrancy here? Don't think so. 483 */ 484 ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 485 486 ++igmpstat.igps_snd_reports; 487 } 488