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 */ 40 41 /* 42 * Internet Group Management Protocol (IGMP) routines. 43 * 44 * Written by Steve Deering, Stanford, May 1988. 45 * Modified by Rosen Sharma, Stanford, Aug 1994. 46 * Modified by Bill Fenner, Xerox PARC, Feb 1995. 47 * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995. 48 * 49 * MULTICAST Revision: 3.5.1.4 50 */ 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/malloc.h> 55 #include <sys/mbuf.h> 56 #include <sys/socket.h> 57 #include <sys/protosw.h> 58 #include <sys/kernel.h> 59 #include <sys/sysctl.h> 60 #include <sys/in_cksum.h> 61 #include <sys/thread2.h> 62 63 #include <machine/stdarg.h> 64 65 #include <net/if.h> 66 #include <net/route.h> 67 68 #include <netinet/in.h> 69 #include <netinet/in_var.h> 70 #include <netinet/in_systm.h> 71 #include <netinet/ip.h> 72 #include <netinet/ip_var.h> 73 #include <netinet/igmp.h> 74 #include <netinet/igmp_var.h> 75 76 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); 77 78 static struct router_info * 79 find_rti (struct ifnet *ifp); 80 81 static struct igmpstat igmpstat; 82 83 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, 84 &igmpstat, igmpstat, "IGMP statistics"); 85 86 static int igmp_timers_are_running; 87 static u_long igmp_all_hosts_group; 88 static u_long igmp_all_rtrs_group; 89 static struct mbuf *router_alert; 90 static struct router_info *Head; 91 92 static void igmp_sendpkt (struct in_multi *, int, unsigned long); 93 94 void 95 igmp_init(void) 96 { 97 struct ipoption *ra; 98 99 /* 100 * To avoid byte-swapping the same value over and over again. 101 */ 102 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 103 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 104 105 igmp_timers_are_running = 0; 106 107 /* 108 * Construct a Router Alert option to use in outgoing packets 109 */ 110 MGET(router_alert, MB_DONTWAIT, MT_DATA); 111 ra = mtod(router_alert, struct ipoption *); 112 ra->ipopt_dst.s_addr = 0; 113 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 114 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 115 ra->ipopt_list[2] = 0x00; 116 ra->ipopt_list[3] = 0x00; 117 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 118 119 Head = NULL; 120 } 121 122 static struct router_info * 123 find_rti(struct ifnet *ifp) 124 { 125 struct router_info *rti = Head; 126 127 #ifdef IGMP_DEBUG 128 kprintf("[igmp.c, _find_rti] --> entering \n"); 129 #endif 130 while (rti) { 131 if (rti->rti_ifp == ifp) { 132 #ifdef IGMP_DEBUG 133 kprintf("[igmp.c, _find_rti] --> found old entry \n"); 134 #endif 135 return rti; 136 } 137 rti = rti->rti_next; 138 } 139 rti = kmalloc(sizeof *rti, M_IGMP, M_INTWAIT); 140 rti->rti_ifp = ifp; 141 rti->rti_type = IGMP_V2_ROUTER; 142 rti->rti_time = 0; 143 rti->rti_next = Head; 144 Head = rti; 145 #ifdef IGMP_DEBUG 146 kprintf("[igmp.c, _find_rti] --> created an entry \n"); 147 #endif 148 return rti; 149 } 150 151 int 152 igmp_input(struct mbuf **mp, int *offp, int proto) 153 { 154 struct mbuf *m = *mp; 155 int iphlen; 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 int timer; /** timer value in the igmp query header **/ 166 167 iphlen = *offp; 168 *mp = NULL; 169 170 ++igmpstat.igps_rcv_total; 171 172 ip = mtod(m, struct ip *); 173 igmplen = ip->ip_len; 174 175 /* 176 * Validate lengths 177 */ 178 if (igmplen < IGMP_MINLEN) { 179 ++igmpstat.igps_rcv_tooshort; 180 m_freem(m); 181 return(IPPROTO_DONE); 182 } 183 minlen = iphlen + IGMP_MINLEN; 184 if ((m->m_flags & M_EXT || m->m_len < minlen) && 185 (m = m_pullup(m, minlen)) == NULL) { 186 ++igmpstat.igps_rcv_tooshort; 187 return(IPPROTO_DONE); 188 } 189 190 /* 191 * Validate checksum 192 */ 193 m->m_data += iphlen; 194 m->m_len -= iphlen; 195 igmp = mtod(m, struct igmp *); 196 if (in_cksum(m, igmplen)) { 197 ++igmpstat.igps_rcv_badsum; 198 m_freem(m); 199 return(IPPROTO_DONE); 200 } 201 m->m_data -= iphlen; 202 m->m_len += iphlen; 203 204 ip = mtod(m, struct ip *); 205 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 206 if (timer == 0) 207 timer = 1; 208 rti = find_rti(ifp); 209 210 /* 211 * In the IGMPv2 specification, there are 3 states and a flag. 212 * 213 * In Non-Member state, we simply don't have a membership record. 214 * In Delaying Member state, our timer is running (inm->inm_timer) 215 * In Idle Member state, our timer is not running (inm->inm_timer==0) 216 * 217 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 218 * we have heard a report from another member, or IGMP_IREPORTEDLAST 219 * if I sent the last report. 220 */ 221 switch (igmp->igmp_type) { 222 223 case IGMP_MEMBERSHIP_QUERY: 224 ++igmpstat.igps_rcv_queries; 225 226 if (ifp->if_flags & IFF_LOOPBACK) 227 break; 228 229 if (igmp->igmp_code == 0) { 230 /* 231 * Old router. Remember that the querier on this 232 * interface is old, and set the timer to the 233 * value in RFC 1112. 234 */ 235 236 rti->rti_type = IGMP_V1_ROUTER; 237 rti->rti_time = 0; 238 239 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 240 241 if (ip->ip_dst.s_addr != igmp_all_hosts_group || 242 igmp->igmp_group.s_addr != 0) { 243 ++igmpstat.igps_rcv_badqueries; 244 m_freem(m); 245 return(IPPROTO_DONE); 246 } 247 } else { 248 /* 249 * New router. Simply do the new validity check. 250 */ 251 252 if (igmp->igmp_group.s_addr != 0 && 253 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 254 ++igmpstat.igps_rcv_badqueries; 255 m_freem(m); 256 return(IPPROTO_DONE); 257 } 258 } 259 260 /* 261 * - Start the timers in all of our membership records 262 * that the query applies to for the interface on 263 * which the query arrived excl. those that belong 264 * to the "all-hosts" group (224.0.0.1). 265 * - Restart any timer that is already running but has 266 * a value longer than the requested timeout. 267 * - Use the value specified in the query message as 268 * the maximum timeout. 269 */ 270 IN_FIRST_MULTI(step, inm); 271 while (inm != NULL) { 272 if (inm->inm_ifp == ifp && 273 inm->inm_addr.s_addr != igmp_all_hosts_group && 274 (igmp->igmp_group.s_addr == 0 || 275 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 276 if (inm->inm_timer == 0 || 277 inm->inm_timer > timer) { 278 inm->inm_timer = 279 IGMP_RANDOM_DELAY(timer); 280 igmp_timers_are_running = 1; 281 } 282 } 283 IN_NEXT_MULTI(step, inm); 284 } 285 286 break; 287 288 case IGMP_V1_MEMBERSHIP_REPORT: 289 case IGMP_V2_MEMBERSHIP_REPORT: 290 /* 291 * For fast leave to work, we have to know that we are the 292 * last person to send a report for this group. Reports 293 * can potentially get looped back if we are a multicast 294 * router, so discard reports sourced by me. 295 */ 296 ia = IFP_TO_IA(ifp); 297 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 298 break; 299 300 ++igmpstat.igps_rcv_reports; 301 302 if (ifp->if_flags & IFF_LOOPBACK) 303 break; 304 305 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 306 ++igmpstat.igps_rcv_badreports; 307 m_freem(m); 308 return(IPPROTO_DONE); 309 } 310 311 /* 312 * KLUDGE: if the IP source address of the report has an 313 * unspecified (i.e., zero) subnet number, as is allowed for 314 * a booting host, replace it with the correct subnet number 315 * so that a process-level multicast routing demon can 316 * determine which subnet it arrived from. This is necessary 317 * to compensate for the lack of any way for a process to 318 * determine the arrival interface of an incoming packet. 319 */ 320 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 321 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 322 323 /* 324 * If we belong to the group being reported, stop 325 * our timer for that group. 326 */ 327 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 328 329 if (inm != NULL) { 330 inm->inm_timer = 0; 331 ++igmpstat.igps_rcv_ourreports; 332 333 inm->inm_state = IGMP_OTHERMEMBER; 334 } 335 336 break; 337 } 338 339 /* 340 * Pass all valid IGMP packets up to any process(es) listening 341 * on a raw IGMP socket. 342 */ 343 *mp = m; 344 rip_input(mp, offp, proto); 345 return(IPPROTO_DONE); 346 } 347 348 void 349 igmp_joingroup(struct in_multi *inm) 350 { 351 crit_enter(); 352 if (inm->inm_addr.s_addr == igmp_all_hosts_group 353 || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 354 inm->inm_timer = 0; 355 inm->inm_state = IGMP_OTHERMEMBER; 356 } else { 357 inm->inm_rti = find_rti(inm->inm_ifp); 358 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 359 inm->inm_timer = IGMP_RANDOM_DELAY( 360 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 361 inm->inm_state = IGMP_IREPORTEDLAST; 362 igmp_timers_are_running = 1; 363 } 364 crit_exit(); 365 } 366 367 void 368 igmp_leavegroup(struct in_multi *inm) 369 { 370 if (inm->inm_state == IGMP_IREPORTEDLAST && 371 inm->inm_addr.s_addr != igmp_all_hosts_group && 372 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 373 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 374 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 375 } 376 377 void 378 igmp_fasttimo(void) 379 { 380 struct in_multi *inm; 381 struct in_multistep step; 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 crit_enter(); 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 crit_exit(); 406 } 407 408 void 409 igmp_slowtimo(void) 410 { 411 struct router_info *rti = Head; 412 413 crit_enter(); 414 #ifdef IGMP_DEBUG 415 kprintf("[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 kprintf("[igmp.c,_slowtimo] -- > exiting \n"); 428 #endif 429 crit_exit(); 430 } 431 432 static struct route igmprt; 433 434 static void 435 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 436 { 437 struct mbuf *m; 438 struct igmp *igmp; 439 struct ip *ip; 440 struct ip_moptions imo; 441 442 MGETHDR(m, MB_DONTWAIT, MT_HEADER); 443 if (m == NULL) 444 return; 445 446 m->m_pkthdr.rcvif = loif; 447 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 448 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 449 m->m_data += sizeof(struct ip); 450 m->m_len = IGMP_MINLEN; 451 igmp = mtod(m, struct igmp *); 452 igmp->igmp_type = type; 453 igmp->igmp_code = 0; 454 igmp->igmp_group = inm->inm_addr; 455 igmp->igmp_cksum = 0; 456 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 457 458 m->m_data -= sizeof(struct ip); 459 m->m_len += sizeof(struct ip); 460 ip = mtod(m, struct ip *); 461 ip->ip_tos = 0; 462 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 463 ip->ip_off = 0; 464 ip->ip_p = IPPROTO_IGMP; 465 ip->ip_src.s_addr = INADDR_ANY; 466 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 467 468 imo.imo_multicast_ifp = inm->inm_ifp; 469 imo.imo_multicast_ttl = 1; 470 imo.imo_multicast_vif = -1; 471 /* 472 * Request loopback of the report if we are acting as a multicast 473 * router, so that the process-level routing demon can hear it. 474 */ 475 imo.imo_multicast_loop = (ip_mrouter != NULL); 476 477 /* 478 * XXX 479 * Do we have to worry about reentrancy here? Don't think so. 480 */ 481 ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 482 483 ++igmpstat.igps_snd_reports; 484 } 485