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. 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: src/sys/netinet/igmp.c,v 1.29.2.2 2003/01/23 21:06:44 sam Exp $ 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 <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/malloc.h> 51 #include <sys/mbuf.h> 52 #include <sys/socket.h> 53 #include <sys/protosw.h> 54 #include <sys/kernel.h> 55 #include <sys/sysctl.h> 56 #include <sys/in_cksum.h> 57 #include <sys/thread2.h> 58 59 #include <machine/stdarg.h> 60 61 #include <net/if.h> 62 #include <net/route.h> 63 #include <net/netmsg2.h> 64 #include <net/netisr2.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 #define IGMP_FASTTIMO (hz / PR_FASTHZ) 75 #define IGMP_SLOWTIMO (hz / PR_SLOWHZ) 76 77 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); 78 79 static struct router_info * 80 find_rti (struct ifnet *ifp); 81 82 static struct igmpstat igmpstat; 83 84 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, 85 &igmpstat, igmpstat, "IGMP statistics"); 86 87 static int igmp_timers_are_running; 88 static u_long igmp_all_hosts_group; 89 static u_long igmp_all_rtrs_group; 90 static struct mbuf *router_alert; 91 static struct router_info *Head; 92 93 static void igmp_sendpkt (struct in_multi *, int, unsigned long); 94 static void igmp_fasttimo_dispatch(netmsg_t); 95 static void igmp_fasttimo(void *); 96 static void igmp_slowtimo_dispatch(netmsg_t); 97 static void igmp_slowtimo(void *); 98 99 static struct netmsg_base igmp_slowtimo_netmsg; 100 static struct callout igmp_slowtimo_ch; 101 static struct netmsg_base igmp_fasttimo_netmsg; 102 static struct callout igmp_fasttimo_ch; 103 104 void 105 igmp_init(void) 106 { 107 struct ipoption *ra; 108 109 /* 110 * To avoid byte-swapping the same value over and over again. 111 */ 112 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 113 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 114 115 igmp_timers_are_running = 0; 116 117 /* 118 * Construct a Router Alert option to use in outgoing packets 119 */ 120 MGET(router_alert, M_NOWAIT, MT_DATA); 121 ra = mtod(router_alert, struct ipoption *); 122 ra->ipopt_dst.s_addr = 0; 123 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 124 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 125 ra->ipopt_list[2] = 0x00; 126 ra->ipopt_list[3] = 0x00; 127 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 128 129 Head = NULL; 130 131 callout_init_mp(&igmp_slowtimo_ch); 132 netmsg_init(&igmp_slowtimo_netmsg, NULL, &netisr_adone_rport, 133 MSGF_PRIORITY, igmp_slowtimo_dispatch); 134 135 callout_init_mp(&igmp_fasttimo_ch); 136 netmsg_init(&igmp_fasttimo_netmsg, NULL, &netisr_adone_rport, 137 MSGF_PRIORITY, igmp_fasttimo_dispatch); 138 139 callout_reset_bycpu(&igmp_slowtimo_ch, IGMP_SLOWTIMO, 140 igmp_slowtimo, NULL, 0); 141 callout_reset_bycpu(&igmp_fasttimo_ch, IGMP_FASTTIMO, 142 igmp_fasttimo, NULL, 0); 143 } 144 145 static struct router_info * 146 find_rti(struct ifnet *ifp) 147 { 148 struct router_info *rti = Head; 149 150 #ifdef IGMP_DEBUG 151 kprintf("[igmp.c, _find_rti] --> entering \n"); 152 #endif 153 while (rti) { 154 if (rti->rti_ifp == ifp) { 155 #ifdef IGMP_DEBUG 156 kprintf("[igmp.c, _find_rti] --> found old entry \n"); 157 #endif 158 return rti; 159 } 160 rti = rti->rti_next; 161 } 162 rti = kmalloc(sizeof *rti, M_IGMP, M_INTWAIT); 163 rti->rti_ifp = ifp; 164 rti->rti_type = IGMP_V2_ROUTER; 165 rti->rti_time = 0; 166 rti->rti_next = Head; 167 Head = rti; 168 #ifdef IGMP_DEBUG 169 kprintf("[igmp.c, _find_rti] --> created an entry \n"); 170 #endif 171 return rti; 172 } 173 174 int 175 igmp_input(struct mbuf **mp, int *offp, int proto) 176 { 177 struct mbuf *m = *mp; 178 int iphlen; 179 struct igmp *igmp; 180 struct ip *ip; 181 int igmplen; 182 struct ifnet *ifp = m->m_pkthdr.rcvif; 183 int minlen; 184 struct in_multi *inm; 185 struct in_ifaddr *ia; 186 struct in_multistep step; 187 struct router_info *rti; 188 int timer; /** timer value in the igmp query header **/ 189 190 iphlen = *offp; 191 *mp = NULL; 192 193 ++igmpstat.igps_rcv_total; 194 195 ip = mtod(m, struct ip *); 196 igmplen = ip->ip_len; 197 198 /* 199 * Validate lengths 200 */ 201 if (igmplen < IGMP_MINLEN) { 202 ++igmpstat.igps_rcv_tooshort; 203 m_freem(m); 204 return(IPPROTO_DONE); 205 } 206 minlen = iphlen + IGMP_MINLEN; 207 if ((m->m_flags & M_EXT || m->m_len < minlen) && 208 (m = m_pullup(m, minlen)) == NULL) { 209 ++igmpstat.igps_rcv_tooshort; 210 return(IPPROTO_DONE); 211 } 212 213 /* 214 * Validate checksum 215 */ 216 m->m_data += iphlen; 217 m->m_len -= iphlen; 218 igmp = mtod(m, struct igmp *); 219 if (in_cksum(m, igmplen)) { 220 ++igmpstat.igps_rcv_badsum; 221 m_freem(m); 222 return(IPPROTO_DONE); 223 } 224 m->m_data -= iphlen; 225 m->m_len += iphlen; 226 227 ip = mtod(m, struct ip *); 228 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 229 if (timer == 0) 230 timer = 1; 231 rti = find_rti(ifp); 232 233 /* 234 * In the IGMPv2 specification, there are 3 states and a flag. 235 * 236 * In Non-Member state, we simply don't have a membership record. 237 * In Delaying Member state, our timer is running (inm->inm_timer) 238 * In Idle Member state, our timer is not running (inm->inm_timer==0) 239 * 240 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 241 * we have heard a report from another member, or IGMP_IREPORTEDLAST 242 * if I sent the last report. 243 */ 244 switch (igmp->igmp_type) { 245 246 case IGMP_MEMBERSHIP_QUERY: 247 ++igmpstat.igps_rcv_queries; 248 249 if (ifp->if_flags & IFF_LOOPBACK) 250 break; 251 252 if (igmp->igmp_code == 0) { 253 /* 254 * Old router. Remember that the querier on this 255 * interface is old, and set the timer to the 256 * value in RFC 1112. 257 */ 258 259 rti->rti_type = IGMP_V1_ROUTER; 260 rti->rti_time = 0; 261 262 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 263 264 if (ip->ip_dst.s_addr != igmp_all_hosts_group || 265 igmp->igmp_group.s_addr != 0) { 266 ++igmpstat.igps_rcv_badqueries; 267 m_freem(m); 268 return(IPPROTO_DONE); 269 } 270 } else { 271 /* 272 * New router. Simply do the new validity check. 273 */ 274 275 if (igmp->igmp_group.s_addr != 0 && 276 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 277 ++igmpstat.igps_rcv_badqueries; 278 m_freem(m); 279 return(IPPROTO_DONE); 280 } 281 } 282 283 /* 284 * - Start the timers in all of our membership records 285 * that the query applies to for the interface on 286 * which the query arrived excl. those that belong 287 * to the "all-hosts" group (224.0.0.1). 288 * - Restart any timer that is already running but has 289 * a value longer than the requested timeout. 290 * - Use the value specified in the query message as 291 * the maximum timeout. 292 */ 293 IN_FIRST_MULTI(step, inm); 294 while (inm != NULL) { 295 if (inm->inm_ifp == ifp && 296 inm->inm_addr.s_addr != igmp_all_hosts_group && 297 (igmp->igmp_group.s_addr == 0 || 298 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 299 if (inm->inm_timer == 0 || 300 inm->inm_timer > timer) { 301 inm->inm_timer = 302 IGMP_RANDOM_DELAY(timer); 303 igmp_timers_are_running = 1; 304 } 305 } 306 IN_NEXT_MULTI(step, inm); 307 } 308 309 break; 310 311 case IGMP_V1_MEMBERSHIP_REPORT: 312 case IGMP_V2_MEMBERSHIP_REPORT: 313 /* 314 * For fast leave to work, we have to know that we are the 315 * last person to send a report for this group. Reports 316 * can potentially get looped back if we are a multicast 317 * router, so discard reports sourced by me. 318 */ 319 ia = IFP_TO_IA(ifp); 320 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 321 break; 322 323 ++igmpstat.igps_rcv_reports; 324 325 if (ifp->if_flags & IFF_LOOPBACK) 326 break; 327 328 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 329 ++igmpstat.igps_rcv_badreports; 330 m_freem(m); 331 return(IPPROTO_DONE); 332 } 333 334 /* 335 * KLUDGE: if the IP source address of the report has an 336 * unspecified (i.e., zero) subnet number, as is allowed for 337 * a booting host, replace it with the correct subnet number 338 * so that a process-level multicast routing demon can 339 * determine which subnet it arrived from. This is necessary 340 * to compensate for the lack of any way for a process to 341 * determine the arrival interface of an incoming packet. 342 */ 343 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 344 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 345 346 /* 347 * If we belong to the group being reported, stop 348 * our timer for that group. 349 */ 350 inm = IN_LOOKUP_MULTI(&igmp->igmp_group, ifp); 351 352 if (inm != NULL) { 353 inm->inm_timer = 0; 354 ++igmpstat.igps_rcv_ourreports; 355 356 inm->inm_state = IGMP_OTHERMEMBER; 357 } 358 359 break; 360 } 361 362 /* 363 * Pass all valid IGMP packets up to any process(es) listening 364 * on a raw IGMP socket. 365 */ 366 *mp = m; 367 rip_input(mp, offp, proto); 368 return(IPPROTO_DONE); 369 } 370 371 void 372 igmp_joingroup(struct in_multi *inm) 373 { 374 crit_enter(); 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 inm->inm_rti = find_rti(inm->inm_ifp); 381 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 382 inm->inm_timer = IGMP_RANDOM_DELAY( 383 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 384 inm->inm_state = IGMP_IREPORTEDLAST; 385 igmp_timers_are_running = 1; 386 } 387 crit_exit(); 388 } 389 390 void 391 igmp_leavegroup(struct in_multi *inm) 392 { 393 if (inm->inm_state == IGMP_IREPORTEDLAST && 394 inm->inm_addr.s_addr != igmp_all_hosts_group && 395 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 396 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 397 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 398 } 399 400 static void 401 igmp_fasttimo(void *dummy __unused) 402 { 403 struct netmsg_base *msg = &igmp_fasttimo_netmsg; 404 405 KKASSERT(mycpuid == 0); 406 407 crit_enter(); 408 if (msg->lmsg.ms_flags & MSGF_DONE) 409 netisr_sendmsg_oncpu(msg); 410 crit_exit(); 411 } 412 413 static void 414 igmp_fasttimo_dispatch(netmsg_t nmsg) 415 { 416 struct in_multi *inm; 417 struct in_multistep step; 418 419 ASSERT_NETISR0; 420 421 crit_enter(); 422 netisr_replymsg(&nmsg->base, 0); /* reply ASAP */ 423 crit_exit(); 424 425 /* 426 * Quick check to see if any work needs to be done, in order 427 * to minimize the overhead of fasttimo processing. 428 */ 429 430 if (!igmp_timers_are_running) 431 goto done; 432 433 igmp_timers_are_running = 0; 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 done: 447 callout_reset(&igmp_fasttimo_ch, IGMP_FASTTIMO, igmp_fasttimo, NULL); 448 } 449 450 static void 451 igmp_slowtimo(void *dummy __unused) 452 { 453 struct netmsg_base *msg = &igmp_slowtimo_netmsg; 454 455 KKASSERT(mycpuid == 0); 456 457 crit_enter(); 458 if (msg->lmsg.ms_flags & MSGF_DONE) 459 netisr_sendmsg_oncpu(msg); 460 crit_exit(); 461 } 462 463 static void 464 igmp_slowtimo_dispatch(netmsg_t nmsg) 465 { 466 struct router_info *rti = Head; 467 468 ASSERT_NETISR0; 469 470 crit_enter(); 471 netisr_replymsg(&nmsg->base, 0); /* reply ASAP */ 472 crit_exit(); 473 474 #ifdef IGMP_DEBUG 475 kprintf("[igmp.c,_slowtimo] -- > entering \n"); 476 #endif 477 while (rti) { 478 if (rti->rti_type == IGMP_V1_ROUTER) { 479 rti->rti_time++; 480 if (rti->rti_time >= IGMP_AGE_THRESHOLD) { 481 rti->rti_type = IGMP_V2_ROUTER; 482 } 483 } 484 rti = rti->rti_next; 485 } 486 #ifdef IGMP_DEBUG 487 kprintf("[igmp.c,_slowtimo] -- > exiting \n"); 488 #endif 489 callout_reset(&igmp_slowtimo_ch, IGMP_SLOWTIMO, igmp_slowtimo, NULL); 490 } 491 492 static struct route igmprt; 493 494 static void 495 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 496 { 497 struct mbuf *m; 498 struct igmp *igmp; 499 struct ip *ip; 500 struct ip_moptions imo; 501 502 MGETHDR(m, M_NOWAIT, MT_HEADER); 503 if (m == NULL) 504 return; 505 506 m->m_pkthdr.rcvif = loif; 507 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 508 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 509 m->m_data += sizeof(struct ip); 510 m->m_len = IGMP_MINLEN; 511 igmp = mtod(m, struct igmp *); 512 igmp->igmp_type = type; 513 igmp->igmp_code = 0; 514 igmp->igmp_group = inm->inm_addr; 515 igmp->igmp_cksum = 0; 516 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 517 518 m->m_data -= sizeof(struct ip); 519 m->m_len += sizeof(struct ip); 520 ip = mtod(m, struct ip *); 521 ip->ip_tos = 0; 522 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 523 ip->ip_off = 0; 524 ip->ip_p = IPPROTO_IGMP; 525 ip->ip_src.s_addr = INADDR_ANY; 526 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 527 528 imo.imo_multicast_ifp = inm->inm_ifp; 529 imo.imo_multicast_ttl = 1; 530 imo.imo_multicast_vif = -1; 531 /* 532 * Request loopback of the report if we are acting as a multicast 533 * router, so that the process-level routing demon can hear it. 534 */ 535 imo.imo_multicast_loop = (ip_mrouter != NULL); 536 537 /* 538 * XXX 539 * Do we have to worry about reentrancy here? Don't think so. 540 */ 541 ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 542 543 ++igmpstat.igps_snd_reports; 544 } 545