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 1.14 2008/06/08 08:38:05 sephe 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 #include <sys/thread2.h> 63 64 #include <machine/stdarg.h> 65 66 #include <net/if.h> 67 #include <net/route.h> 68 69 #include <netinet/in.h> 70 #include <netinet/in_var.h> 71 #include <netinet/in_systm.h> 72 #include <netinet/ip.h> 73 #include <netinet/ip_var.h> 74 #include <netinet/igmp.h> 75 #include <netinet/igmp_var.h> 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, ""); 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 95 void 96 igmp_init(void) 97 { 98 struct ipoption *ra; 99 100 /* 101 * To avoid byte-swapping the same value over and over again. 102 */ 103 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 104 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 105 106 igmp_timers_are_running = 0; 107 108 /* 109 * Construct a Router Alert option to use in outgoing packets 110 */ 111 MGET(router_alert, MB_DONTWAIT, MT_DATA); 112 ra = mtod(router_alert, struct ipoption *); 113 ra->ipopt_dst.s_addr = 0; 114 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 115 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 116 ra->ipopt_list[2] = 0x00; 117 ra->ipopt_list[3] = 0x00; 118 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 119 120 Head = (struct router_info *) 0; 121 } 122 123 static struct router_info * 124 find_rti(struct ifnet *ifp) 125 { 126 struct router_info *rti = Head; 127 128 #ifdef IGMP_DEBUG 129 kprintf("[igmp.c, _find_rti] --> entering \n"); 130 #endif 131 while (rti) { 132 if (rti->rti_ifp == ifp) { 133 #ifdef IGMP_DEBUG 134 kprintf("[igmp.c, _find_rti] --> found old entry \n"); 135 #endif 136 return rti; 137 } 138 rti = rti->rti_next; 139 } 140 MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_INTWAIT); 141 rti->rti_ifp = ifp; 142 rti->rti_type = IGMP_V2_ROUTER; 143 rti->rti_time = 0; 144 rti->rti_next = Head; 145 Head = rti; 146 #ifdef IGMP_DEBUG 147 kprintf("[igmp.c, _find_rti] --> created an entry \n"); 148 #endif 149 return rti; 150 } 151 152 void 153 igmp_input(struct mbuf *m, ...) 154 { 155 int iphlen, off, proto; 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 __va_list ap; 166 167 int timer; /** timer value in the igmp query header **/ 168 169 __va_start(ap, m); 170 off = __va_arg(ap, int); 171 proto = __va_arg(ap, int); 172 __va_end(ap); 173 174 iphlen = off; 175 176 ++igmpstat.igps_rcv_total; 177 178 ip = mtod(m, struct ip *); 179 igmplen = ip->ip_len; 180 181 /* 182 * Validate lengths 183 */ 184 if (igmplen < IGMP_MINLEN) { 185 ++igmpstat.igps_rcv_tooshort; 186 m_freem(m); 187 return; 188 } 189 minlen = iphlen + IGMP_MINLEN; 190 if ((m->m_flags & M_EXT || m->m_len < minlen) && 191 (m = m_pullup(m, minlen)) == 0) { 192 ++igmpstat.igps_rcv_tooshort; 193 return; 194 } 195 196 /* 197 * Validate checksum 198 */ 199 m->m_data += iphlen; 200 m->m_len -= iphlen; 201 igmp = mtod(m, struct igmp *); 202 if (in_cksum(m, igmplen)) { 203 ++igmpstat.igps_rcv_badsum; 204 m_freem(m); 205 return; 206 } 207 m->m_data -= iphlen; 208 m->m_len += iphlen; 209 210 ip = mtod(m, struct ip *); 211 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 212 if (timer == 0) 213 timer = 1; 214 rti = find_rti(ifp); 215 216 /* 217 * In the IGMPv2 specification, there are 3 states and a flag. 218 * 219 * In Non-Member state, we simply don't have a membership record. 220 * In Delaying Member state, our timer is running (inm->inm_timer) 221 * In Idle Member state, our timer is not running (inm->inm_timer==0) 222 * 223 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 224 * we have heard a report from another member, or IGMP_IREPORTEDLAST 225 * if I sent the last report. 226 */ 227 switch (igmp->igmp_type) { 228 229 case IGMP_MEMBERSHIP_QUERY: 230 ++igmpstat.igps_rcv_queries; 231 232 if (ifp->if_flags & IFF_LOOPBACK) 233 break; 234 235 if (igmp->igmp_code == 0) { 236 /* 237 * Old router. Remember that the querier on this 238 * interface is old, and set the timer to the 239 * value in RFC 1112. 240 */ 241 242 rti->rti_type = IGMP_V1_ROUTER; 243 rti->rti_time = 0; 244 245 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 246 247 if (ip->ip_dst.s_addr != igmp_all_hosts_group || 248 igmp->igmp_group.s_addr != 0) { 249 ++igmpstat.igps_rcv_badqueries; 250 m_freem(m); 251 return; 252 } 253 } else { 254 /* 255 * New router. Simply do the new validity check. 256 */ 257 258 if (igmp->igmp_group.s_addr != 0 && 259 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 260 ++igmpstat.igps_rcv_badqueries; 261 m_freem(m); 262 return; 263 } 264 } 265 266 /* 267 * - Start the timers in all of our membership records 268 * that the query applies to for the interface on 269 * which the query arrived excl. those that belong 270 * to the "all-hosts" group (224.0.0.1). 271 * - Restart any timer that is already running but has 272 * a value longer than the requested timeout. 273 * - Use the value specified in the query message as 274 * the maximum timeout. 275 */ 276 IN_FIRST_MULTI(step, inm); 277 while (inm != NULL) { 278 if (inm->inm_ifp == ifp && 279 inm->inm_addr.s_addr != igmp_all_hosts_group && 280 (igmp->igmp_group.s_addr == 0 || 281 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 282 if (inm->inm_timer == 0 || 283 inm->inm_timer > timer) { 284 inm->inm_timer = 285 IGMP_RANDOM_DELAY(timer); 286 igmp_timers_are_running = 1; 287 } 288 } 289 IN_NEXT_MULTI(step, inm); 290 } 291 292 break; 293 294 case IGMP_V1_MEMBERSHIP_REPORT: 295 case IGMP_V2_MEMBERSHIP_REPORT: 296 /* 297 * For fast leave to work, we have to know that we are the 298 * last person to send a report for this group. Reports 299 * can potentially get looped back if we are a multicast 300 * router, so discard reports sourced by me. 301 */ 302 ia = IFP_TO_IA(ifp); 303 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 304 break; 305 306 ++igmpstat.igps_rcv_reports; 307 308 if (ifp->if_flags & IFF_LOOPBACK) 309 break; 310 311 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 312 ++igmpstat.igps_rcv_badreports; 313 m_freem(m); 314 return; 315 } 316 317 /* 318 * KLUDGE: if the IP source address of the report has an 319 * unspecified (i.e., zero) subnet number, as is allowed for 320 * a booting host, replace it with the correct subnet number 321 * so that a process-level multicast routing demon can 322 * determine which subnet it arrived from. This is necessary 323 * to compensate for the lack of any way for a process to 324 * determine the arrival interface of an incoming packet. 325 */ 326 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 327 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 328 329 /* 330 * If we belong to the group being reported, stop 331 * our timer for that group. 332 */ 333 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 334 335 if (inm != NULL) { 336 inm->inm_timer = 0; 337 ++igmpstat.igps_rcv_ourreports; 338 339 inm->inm_state = IGMP_OTHERMEMBER; 340 } 341 342 break; 343 } 344 345 /* 346 * Pass all valid IGMP packets up to any process(es) listening 347 * on a raw IGMP socket. 348 */ 349 rip_input(m, off, proto); 350 } 351 352 void 353 igmp_joingroup(struct in_multi *inm) 354 { 355 crit_enter(); 356 if (inm->inm_addr.s_addr == igmp_all_hosts_group 357 || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 358 inm->inm_timer = 0; 359 inm->inm_state = IGMP_OTHERMEMBER; 360 } else { 361 inm->inm_rti = find_rti(inm->inm_ifp); 362 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 363 inm->inm_timer = IGMP_RANDOM_DELAY( 364 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 365 inm->inm_state = IGMP_IREPORTEDLAST; 366 igmp_timers_are_running = 1; 367 } 368 crit_exit(); 369 } 370 371 void 372 igmp_leavegroup(struct in_multi *inm) 373 { 374 if (inm->inm_state == IGMP_IREPORTEDLAST && 375 inm->inm_addr.s_addr != igmp_all_hosts_group && 376 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 377 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 378 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 379 } 380 381 void 382 igmp_fasttimo(void) 383 { 384 struct in_multi *inm; 385 struct in_multistep step; 386 387 /* 388 * Quick check to see if any work needs to be done, in order 389 * to minimize the overhead of fasttimo processing. 390 */ 391 392 if (!igmp_timers_are_running) 393 return; 394 395 crit_enter(); 396 igmp_timers_are_running = 0; 397 IN_FIRST_MULTI(step, inm); 398 while (inm != NULL) { 399 if (inm->inm_timer == 0) { 400 /* do nothing */ 401 } else if (--inm->inm_timer == 0) { 402 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 403 inm->inm_state = IGMP_IREPORTEDLAST; 404 } else { 405 igmp_timers_are_running = 1; 406 } 407 IN_NEXT_MULTI(step, inm); 408 } 409 crit_exit(); 410 } 411 412 void 413 igmp_slowtimo(void) 414 { 415 struct router_info *rti = Head; 416 417 crit_enter(); 418 #ifdef IGMP_DEBUG 419 kprintf("[igmp.c,_slowtimo] -- > entering \n"); 420 #endif 421 while (rti) { 422 if (rti->rti_type == IGMP_V1_ROUTER) { 423 rti->rti_time++; 424 if (rti->rti_time >= IGMP_AGE_THRESHOLD) { 425 rti->rti_type = IGMP_V2_ROUTER; 426 } 427 } 428 rti = rti->rti_next; 429 } 430 #ifdef IGMP_DEBUG 431 kprintf("[igmp.c,_slowtimo] -- > exiting \n"); 432 #endif 433 crit_exit(); 434 } 435 436 static struct route igmprt; 437 438 static void 439 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 440 { 441 struct mbuf *m; 442 struct igmp *igmp; 443 struct ip *ip; 444 struct ip_moptions imo; 445 446 MGETHDR(m, MB_DONTWAIT, MT_HEADER); 447 if (m == NULL) 448 return; 449 450 m->m_pkthdr.rcvif = loif; 451 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 452 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 453 m->m_data += sizeof(struct ip); 454 m->m_len = IGMP_MINLEN; 455 igmp = mtod(m, struct igmp *); 456 igmp->igmp_type = type; 457 igmp->igmp_code = 0; 458 igmp->igmp_group = inm->inm_addr; 459 igmp->igmp_cksum = 0; 460 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 461 462 m->m_data -= sizeof(struct ip); 463 m->m_len += sizeof(struct ip); 464 ip = mtod(m, struct ip *); 465 ip->ip_tos = 0; 466 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 467 ip->ip_off = 0; 468 ip->ip_p = IPPROTO_IGMP; 469 ip->ip_src.s_addr = INADDR_ANY; 470 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 471 472 imo.imo_multicast_ifp = inm->inm_ifp; 473 imo.imo_multicast_ttl = 1; 474 imo.imo_multicast_vif = -1; 475 /* 476 * Request loopback of the report if we are acting as a multicast 477 * router, so that the process-level routing demon can hear it. 478 */ 479 imo.imo_multicast_loop = (ip_mrouter != NULL); 480 481 /* 482 * XXX 483 * Do we have to worry about reentrancy here? Don't think so. 484 */ 485 ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 486 487 ++igmpstat.igps_snd_reports; 488 } 489