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 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, "IGMP statistics"); 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 struct netmsg_base igmp_slowtimo_netmsg; 91 static struct netmsg_base igmp_fasttimo_netmsg; 92 93 static void igmp_sendpkt (struct in_multi *, int, unsigned long); 94 static void igmp_slowtimo_dispatch(netmsg_t); 95 static void igmp_fasttimo_dispatch(netmsg_t); 96 97 void 98 igmp_init(void) 99 { 100 struct ipoption *ra; 101 102 /* 103 * To avoid byte-swapping the same value over and over again. 104 */ 105 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 106 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 107 108 igmp_timers_are_running = 0; 109 110 /* 111 * Construct a Router Alert option to use in outgoing packets 112 */ 113 MGET(router_alert, M_NOWAIT, MT_DATA); 114 ra = mtod(router_alert, struct ipoption *); 115 ra->ipopt_dst.s_addr = 0; 116 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 117 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 118 ra->ipopt_list[2] = 0x00; 119 ra->ipopt_list[3] = 0x00; 120 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 121 122 Head = NULL; 123 124 netmsg_init(&igmp_slowtimo_netmsg, NULL, &netisr_adone_rport, 125 MSGF_PRIORITY, igmp_slowtimo_dispatch); 126 netmsg_init(&igmp_fasttimo_netmsg, NULL, &netisr_adone_rport, 127 MSGF_PRIORITY, igmp_fasttimo_dispatch); 128 } 129 130 static struct router_info * 131 find_rti(struct ifnet *ifp) 132 { 133 struct router_info *rti = Head; 134 135 #ifdef IGMP_DEBUG 136 kprintf("[igmp.c, _find_rti] --> entering \n"); 137 #endif 138 while (rti) { 139 if (rti->rti_ifp == ifp) { 140 #ifdef IGMP_DEBUG 141 kprintf("[igmp.c, _find_rti] --> found old entry \n"); 142 #endif 143 return rti; 144 } 145 rti = rti->rti_next; 146 } 147 rti = kmalloc(sizeof *rti, M_IGMP, M_INTWAIT); 148 rti->rti_ifp = ifp; 149 rti->rti_type = IGMP_V2_ROUTER; 150 rti->rti_time = 0; 151 rti->rti_next = Head; 152 Head = rti; 153 #ifdef IGMP_DEBUG 154 kprintf("[igmp.c, _find_rti] --> created an entry \n"); 155 #endif 156 return rti; 157 } 158 159 int 160 igmp_input(struct mbuf **mp, int *offp, int proto) 161 { 162 struct mbuf *m = *mp; 163 int iphlen; 164 struct igmp *igmp; 165 struct ip *ip; 166 int igmplen; 167 struct ifnet *ifp = m->m_pkthdr.rcvif; 168 int minlen; 169 struct in_multi *inm; 170 struct in_ifaddr *ia; 171 struct in_multistep step; 172 struct router_info *rti; 173 int timer; /** timer value in the igmp query header **/ 174 175 iphlen = *offp; 176 *mp = NULL; 177 178 ++igmpstat.igps_rcv_total; 179 180 ip = mtod(m, struct ip *); 181 igmplen = ip->ip_len; 182 183 /* 184 * Validate lengths 185 */ 186 if (igmplen < IGMP_MINLEN) { 187 ++igmpstat.igps_rcv_tooshort; 188 m_freem(m); 189 return(IPPROTO_DONE); 190 } 191 minlen = iphlen + IGMP_MINLEN; 192 if ((m->m_flags & M_EXT || m->m_len < minlen) && 193 (m = m_pullup(m, minlen)) == NULL) { 194 ++igmpstat.igps_rcv_tooshort; 195 return(IPPROTO_DONE); 196 } 197 198 /* 199 * Validate checksum 200 */ 201 m->m_data += iphlen; 202 m->m_len -= iphlen; 203 igmp = mtod(m, struct igmp *); 204 if (in_cksum(m, igmplen)) { 205 ++igmpstat.igps_rcv_badsum; 206 m_freem(m); 207 return(IPPROTO_DONE); 208 } 209 m->m_data -= iphlen; 210 m->m_len += iphlen; 211 212 ip = mtod(m, struct ip *); 213 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 214 if (timer == 0) 215 timer = 1; 216 rti = find_rti(ifp); 217 218 /* 219 * In the IGMPv2 specification, there are 3 states and a flag. 220 * 221 * In Non-Member state, we simply don't have a membership record. 222 * In Delaying Member state, our timer is running (inm->inm_timer) 223 * In Idle Member state, our timer is not running (inm->inm_timer==0) 224 * 225 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 226 * we have heard a report from another member, or IGMP_IREPORTEDLAST 227 * if I sent the last report. 228 */ 229 switch (igmp->igmp_type) { 230 231 case IGMP_MEMBERSHIP_QUERY: 232 ++igmpstat.igps_rcv_queries; 233 234 if (ifp->if_flags & IFF_LOOPBACK) 235 break; 236 237 if (igmp->igmp_code == 0) { 238 /* 239 * Old router. Remember that the querier on this 240 * interface is old, and set the timer to the 241 * value in RFC 1112. 242 */ 243 244 rti->rti_type = IGMP_V1_ROUTER; 245 rti->rti_time = 0; 246 247 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 248 249 if (ip->ip_dst.s_addr != igmp_all_hosts_group || 250 igmp->igmp_group.s_addr != 0) { 251 ++igmpstat.igps_rcv_badqueries; 252 m_freem(m); 253 return(IPPROTO_DONE); 254 } 255 } else { 256 /* 257 * New router. Simply do the new validity check. 258 */ 259 260 if (igmp->igmp_group.s_addr != 0 && 261 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 262 ++igmpstat.igps_rcv_badqueries; 263 m_freem(m); 264 return(IPPROTO_DONE); 265 } 266 } 267 268 /* 269 * - Start the timers in all of our membership records 270 * that the query applies to for the interface on 271 * which the query arrived excl. those that belong 272 * to the "all-hosts" group (224.0.0.1). 273 * - Restart any timer that is already running but has 274 * a value longer than the requested timeout. 275 * - Use the value specified in the query message as 276 * the maximum timeout. 277 */ 278 IN_FIRST_MULTI(step, inm); 279 while (inm != NULL) { 280 if (inm->inm_ifp == ifp && 281 inm->inm_addr.s_addr != igmp_all_hosts_group && 282 (igmp->igmp_group.s_addr == 0 || 283 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 284 if (inm->inm_timer == 0 || 285 inm->inm_timer > timer) { 286 inm->inm_timer = 287 IGMP_RANDOM_DELAY(timer); 288 igmp_timers_are_running = 1; 289 } 290 } 291 IN_NEXT_MULTI(step, inm); 292 } 293 294 break; 295 296 case IGMP_V1_MEMBERSHIP_REPORT: 297 case IGMP_V2_MEMBERSHIP_REPORT: 298 /* 299 * For fast leave to work, we have to know that we are the 300 * last person to send a report for this group. Reports 301 * can potentially get looped back if we are a multicast 302 * router, so discard reports sourced by me. 303 */ 304 ia = IFP_TO_IA(ifp); 305 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 306 break; 307 308 ++igmpstat.igps_rcv_reports; 309 310 if (ifp->if_flags & IFF_LOOPBACK) 311 break; 312 313 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 314 ++igmpstat.igps_rcv_badreports; 315 m_freem(m); 316 return(IPPROTO_DONE); 317 } 318 319 /* 320 * KLUDGE: if the IP source address of the report has an 321 * unspecified (i.e., zero) subnet number, as is allowed for 322 * a booting host, replace it with the correct subnet number 323 * so that a process-level multicast routing demon can 324 * determine which subnet it arrived from. This is necessary 325 * to compensate for the lack of any way for a process to 326 * determine the arrival interface of an incoming packet. 327 */ 328 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 329 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 330 331 /* 332 * If we belong to the group being reported, stop 333 * our timer for that group. 334 */ 335 inm = IN_LOOKUP_MULTI(&igmp->igmp_group, ifp); 336 337 if (inm != NULL) { 338 inm->inm_timer = 0; 339 ++igmpstat.igps_rcv_ourreports; 340 341 inm->inm_state = IGMP_OTHERMEMBER; 342 } 343 344 break; 345 } 346 347 /* 348 * Pass all valid IGMP packets up to any process(es) listening 349 * on a raw IGMP socket. 350 */ 351 *mp = m; 352 rip_input(mp, offp, proto); 353 return(IPPROTO_DONE); 354 } 355 356 void 357 igmp_joingroup(struct in_multi *inm) 358 { 359 crit_enter(); 360 if (inm->inm_addr.s_addr == igmp_all_hosts_group 361 || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 362 inm->inm_timer = 0; 363 inm->inm_state = IGMP_OTHERMEMBER; 364 } else { 365 inm->inm_rti = find_rti(inm->inm_ifp); 366 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 367 inm->inm_timer = IGMP_RANDOM_DELAY( 368 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 369 inm->inm_state = IGMP_IREPORTEDLAST; 370 igmp_timers_are_running = 1; 371 } 372 crit_exit(); 373 } 374 375 void 376 igmp_leavegroup(struct in_multi *inm) 377 { 378 if (inm->inm_state == IGMP_IREPORTEDLAST && 379 inm->inm_addr.s_addr != igmp_all_hosts_group && 380 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 381 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 382 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 383 } 384 385 static void 386 igmp_fasttimo_ipi(void *arg __unused) 387 { 388 struct lwkt_msg *msg = &igmp_fasttimo_netmsg.lmsg; 389 390 crit_enter(); 391 if (msg->ms_flags & MSGF_DONE) 392 lwkt_sendmsg_oncpu(netisr_cpuport(0), msg); 393 crit_exit(); 394 } 395 396 void 397 igmp_fasttimo(void) 398 { 399 lwkt_send_ipiq_bycpu(0, igmp_fasttimo_ipi, NULL); 400 } 401 402 static void 403 igmp_fasttimo_dispatch(netmsg_t nmsg) 404 { 405 struct in_multi *inm; 406 struct in_multistep step; 407 408 crit_enter(); 409 lwkt_replymsg(&nmsg->lmsg, 0); /* reply ASAP */ 410 crit_exit(); 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 igmp_timers_are_running = 0; 421 IN_FIRST_MULTI(step, inm); 422 while (inm != NULL) { 423 if (inm->inm_timer == 0) { 424 /* do nothing */ 425 } else if (--inm->inm_timer == 0) { 426 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 427 inm->inm_state = IGMP_IREPORTEDLAST; 428 } else { 429 igmp_timers_are_running = 1; 430 } 431 IN_NEXT_MULTI(step, inm); 432 } 433 } 434 435 static void 436 igmp_slowtimo_ipi(void *arg __unused) 437 { 438 struct lwkt_msg *msg = &igmp_slowtimo_netmsg.lmsg; 439 440 crit_enter(); 441 if (msg->ms_flags & MSGF_DONE) 442 lwkt_sendmsg_oncpu(netisr_cpuport(0), msg); 443 crit_exit(); 444 } 445 446 void 447 igmp_slowtimo(void) 448 { 449 lwkt_send_ipiq_bycpu(0, igmp_slowtimo_ipi, NULL); 450 } 451 452 static void 453 igmp_slowtimo_dispatch(netmsg_t nmsg) 454 { 455 struct router_info *rti = Head; 456 457 crit_enter(); 458 lwkt_replymsg(&nmsg->lmsg, 0); /* reply ASAP */ 459 crit_exit(); 460 461 #ifdef IGMP_DEBUG 462 kprintf("[igmp.c,_slowtimo] -- > entering \n"); 463 #endif 464 while (rti) { 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 rti = rti->rti_next; 472 } 473 #ifdef IGMP_DEBUG 474 kprintf("[igmp.c,_slowtimo] -- > exiting \n"); 475 #endif 476 } 477 478 static struct route igmprt; 479 480 static void 481 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 482 { 483 struct mbuf *m; 484 struct igmp *igmp; 485 struct ip *ip; 486 struct ip_moptions imo; 487 488 MGETHDR(m, M_NOWAIT, MT_HEADER); 489 if (m == NULL) 490 return; 491 492 m->m_pkthdr.rcvif = loif; 493 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 494 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 495 m->m_data += sizeof(struct ip); 496 m->m_len = IGMP_MINLEN; 497 igmp = mtod(m, struct igmp *); 498 igmp->igmp_type = type; 499 igmp->igmp_code = 0; 500 igmp->igmp_group = inm->inm_addr; 501 igmp->igmp_cksum = 0; 502 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 503 504 m->m_data -= sizeof(struct ip); 505 m->m_len += sizeof(struct ip); 506 ip = mtod(m, struct ip *); 507 ip->ip_tos = 0; 508 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 509 ip->ip_off = 0; 510 ip->ip_p = IPPROTO_IGMP; 511 ip->ip_src.s_addr = INADDR_ANY; 512 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 513 514 imo.imo_multicast_ifp = inm->inm_ifp; 515 imo.imo_multicast_ttl = 1; 516 imo.imo_multicast_vif = -1; 517 /* 518 * Request loopback of the report if we are acting as a multicast 519 * router, so that the process-level routing demon can hear it. 520 */ 521 imo.imo_multicast_loop = (ip_mrouter != NULL); 522 523 /* 524 * XXX 525 * Do we have to worry about reentrancy here? Don't think so. 526 */ 527 ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 528 529 ++igmpstat.igps_snd_reports; 530 } 531