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 * $Id: igmp.c,v 1.16 1996/03/14 16:59:16 fenner 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/mbuf.h> 55 #include <sys/socket.h> 56 #include <sys/protosw.h> 57 #include <sys/kernel.h> 58 #include <sys/sysctl.h> 59 60 #include <net/if.h> 61 #include <net/route.h> 62 63 #include <netinet/in.h> 64 #include <netinet/in_var.h> 65 #include <netinet/in_systm.h> 66 #include <netinet/ip.h> 67 #include <netinet/ip_var.h> 68 #include <netinet/igmp.h> 69 #include <netinet/igmp_var.h> 70 71 static int fill_rti __P((struct in_multi *inm)); 72 static struct router_info * 73 find_rti __P((struct ifnet *ifp)); 74 75 static struct igmpstat igmpstat; 76 77 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD, 78 &igmpstat, igmpstat, ""); 79 80 static int igmp_timers_are_running; 81 static u_long igmp_all_hosts_group; 82 static u_long igmp_all_rtrs_group; 83 static struct mbuf *router_alert; 84 static struct router_info *Head; 85 86 static void igmp_sendpkt(struct in_multi *, int, unsigned long); 87 88 void 89 igmp_init() 90 { 91 struct ipoption *ra; 92 93 /* 94 * To avoid byte-swapping the same value over and over again. 95 */ 96 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 97 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 98 99 igmp_timers_are_running = 0; 100 101 /* 102 * Construct a Router Alert option to use in outgoing packets 103 */ 104 MGET(router_alert, M_DONTWAIT, MT_DATA); 105 ra = mtod(router_alert, struct ipoption *); 106 ra->ipopt_dst.s_addr = 0; 107 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 108 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 109 ra->ipopt_list[2] = 0x00; 110 ra->ipopt_list[3] = 0x00; 111 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 112 113 Head = (struct router_info *) 0; 114 } 115 116 static struct router_info * 117 find_rti(ifp) 118 struct ifnet *ifp; 119 { 120 register struct router_info *rti = Head; 121 122 #ifdef IGMP_DEBUG 123 printf("[igmp.c, _find_rti] --> entering \n"); 124 #endif 125 while (rti) { 126 if (rti->rti_ifp == ifp) { 127 #ifdef IGMP_DEBUG 128 printf("[igmp.c, _find_rti] --> found old entry \n"); 129 #endif 130 return rti; 131 } 132 rti = rti->rti_next; 133 } 134 MALLOC(rti, struct router_info *, sizeof *rti, M_MRTABLE, M_NOWAIT); 135 rti->rti_ifp = ifp; 136 rti->rti_type = IGMP_V2_ROUTER; 137 rti->rti_time = 0; 138 rti->rti_next = Head; 139 Head = rti; 140 #ifdef IGMP_DEBUG 141 printf("[igmp.c, _find_rti] --> created an entry \n"); 142 #endif 143 return rti; 144 } 145 146 void 147 igmp_input(m, iphlen) 148 register struct mbuf *m; 149 register int iphlen; 150 { 151 register struct igmp *igmp; 152 register struct ip *ip; 153 register int igmplen; 154 register struct ifnet *ifp = m->m_pkthdr.rcvif; 155 register int minlen; 156 register struct in_multi *inm; 157 register struct in_ifaddr *ia; 158 struct in_multistep step; 159 struct router_info *rti; 160 161 int timer; /** timer value in the igmp query header **/ 162 163 ++igmpstat.igps_rcv_total; 164 165 ip = mtod(m, struct ip *); 166 igmplen = ip->ip_len; 167 168 /* 169 * Validate lengths 170 */ 171 if (igmplen < IGMP_MINLEN) { 172 ++igmpstat.igps_rcv_tooshort; 173 m_freem(m); 174 return; 175 } 176 minlen = iphlen + IGMP_MINLEN; 177 if ((m->m_flags & M_EXT || m->m_len < minlen) && 178 (m = m_pullup(m, minlen)) == 0) { 179 ++igmpstat.igps_rcv_tooshort; 180 return; 181 } 182 183 /* 184 * Validate checksum 185 */ 186 m->m_data += iphlen; 187 m->m_len -= iphlen; 188 igmp = mtod(m, struct igmp *); 189 if (in_cksum(m, igmplen)) { 190 ++igmpstat.igps_rcv_badsum; 191 m_freem(m); 192 return; 193 } 194 m->m_data -= iphlen; 195 m->m_len += iphlen; 196 197 ip = mtod(m, struct ip *); 198 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 199 rti = find_rti(ifp); 200 201 /* 202 * In the IGMPv2 specification, there are 3 states and a flag. 203 * 204 * In Non-Member state, we simply don't have a membership record. 205 * In Delaying Member state, our timer is running (inm->inm_timer) 206 * In Idle Member state, our timer is not running (inm->inm_timer==0) 207 * 208 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 209 * we have heard a report from another member, or IGMP_IREPORTEDLAST 210 * if I sent the last report. 211 */ 212 switch (igmp->igmp_type) { 213 214 case IGMP_MEMBERSHIP_QUERY: 215 ++igmpstat.igps_rcv_queries; 216 217 if (ifp->if_flags & IFF_LOOPBACK) 218 break; 219 220 if (igmp->igmp_code == 0) { 221 /* 222 * Old router. Remember that the querier on this 223 * interface is old, and set the timer to the 224 * value in RFC 1112. 225 */ 226 227 rti->rti_type = IGMP_V1_ROUTER; 228 rti->rti_time = 0; 229 230 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 231 232 if (ip->ip_dst.s_addr != igmp_all_hosts_group || 233 igmp->igmp_group.s_addr != 0) { 234 ++igmpstat.igps_rcv_badqueries; 235 m_freem(m); 236 return; 237 } 238 } else { 239 /* 240 * New router. Simply do the new validity check. 241 */ 242 243 if (igmp->igmp_group.s_addr != 0 && 244 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 245 ++igmpstat.igps_rcv_badqueries; 246 m_freem(m); 247 return; 248 } 249 } 250 251 /* 252 * - Start the timers in all of our membership records 253 * that the query applies to for the interface on 254 * which the query arrived excl. those that belong 255 * to the "all-hosts" group (224.0.0.1). 256 * - Restart any timer that is already running but has 257 * a value longer than the requested timeout. 258 * - Use the value specified in the query message as 259 * the maximum timeout. 260 */ 261 IN_FIRST_MULTI(step, inm); 262 while (inm != NULL) { 263 if (inm->inm_ifp == ifp && 264 inm->inm_addr.s_addr != igmp_all_hosts_group && 265 (igmp->igmp_group.s_addr == 0 || 266 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 267 if (inm->inm_timer == 0 || 268 inm->inm_timer > timer) { 269 inm->inm_timer = 270 IGMP_RANDOM_DELAY(timer); 271 igmp_timers_are_running = 1; 272 } 273 } 274 IN_NEXT_MULTI(step, inm); 275 } 276 277 break; 278 279 case IGMP_V1_MEMBERSHIP_REPORT: 280 case IGMP_V2_MEMBERSHIP_REPORT: 281 /* 282 * For fast leave to work, we have to know that we are the 283 * last person to send a report for this group. Reports 284 * can potentially get looped back if we are a multicast 285 * router, so discard reports sourced by me. 286 */ 287 IFP_TO_IA(ifp, ia); 288 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 289 break; 290 291 ++igmpstat.igps_rcv_reports; 292 293 if (ifp->if_flags & IFF_LOOPBACK) 294 break; 295 296 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 297 ++igmpstat.igps_rcv_badreports; 298 m_freem(m); 299 return; 300 } 301 302 /* 303 * KLUDGE: if the IP source address of the report has an 304 * unspecified (i.e., zero) subnet number, as is allowed for 305 * a booting host, replace it with the correct subnet number 306 * so that a process-level multicast routing demon can 307 * determine which subnet it arrived from. This is necessary 308 * to compensate for the lack of any way for a process to 309 * determine the arrival interface of an incoming packet. 310 */ 311 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 312 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 313 314 /* 315 * If we belong to the group being reported, stop 316 * our timer for that group. 317 */ 318 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 319 320 if (inm != NULL) { 321 inm->inm_timer = 0; 322 ++igmpstat.igps_rcv_ourreports; 323 324 inm->inm_state = IGMP_OTHERMEMBER; 325 } 326 327 break; 328 } 329 330 /* 331 * Pass all valid IGMP packets up to any process(es) listening 332 * on a raw IGMP socket. 333 */ 334 rip_input(m, iphlen); 335 } 336 337 void 338 igmp_joingroup(inm) 339 struct in_multi *inm; 340 { 341 int s = splnet(); 342 343 if (inm->inm_addr.s_addr == igmp_all_hosts_group 344 || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 345 inm->inm_timer = 0; 346 inm->inm_state = IGMP_OTHERMEMBER; 347 } else { 348 inm->inm_rti = find_rti(inm->inm_ifp); 349 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 350 inm->inm_timer = IGMP_RANDOM_DELAY( 351 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 352 inm->inm_state = IGMP_IREPORTEDLAST; 353 igmp_timers_are_running = 1; 354 } 355 splx(s); 356 } 357 358 void 359 igmp_leavegroup(inm) 360 struct in_multi *inm; 361 { 362 if (inm->inm_state == IGMP_IREPORTEDLAST && 363 inm->inm_addr.s_addr != igmp_all_hosts_group && 364 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 365 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 366 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 367 } 368 369 void 370 igmp_fasttimo() 371 { 372 register struct in_multi *inm; 373 struct in_multistep step; 374 int s; 375 376 /* 377 * Quick check to see if any work needs to be done, in order 378 * to minimize the overhead of fasttimo processing. 379 */ 380 381 if (!igmp_timers_are_running) 382 return; 383 384 s = splnet(); 385 igmp_timers_are_running = 0; 386 IN_FIRST_MULTI(step, inm); 387 while (inm != NULL) { 388 if (inm->inm_timer == 0) { 389 /* do nothing */ 390 } else if (--inm->inm_timer == 0) { 391 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 392 inm->inm_state = IGMP_IREPORTEDLAST; 393 } else { 394 igmp_timers_are_running = 1; 395 } 396 IN_NEXT_MULTI(step, inm); 397 } 398 splx(s); 399 } 400 401 void 402 igmp_slowtimo() 403 { 404 int s = splnet(); 405 register struct router_info *rti = Head; 406 407 #ifdef IGMP_DEBUG 408 printf("[igmp.c,_slowtimo] -- > entering \n"); 409 #endif 410 while (rti) { 411 if (rti->rti_type == IGMP_V1_ROUTER) { 412 rti->rti_time++; 413 if (rti->rti_time >= IGMP_AGE_THRESHOLD) { 414 rti->rti_type = IGMP_V2_ROUTER; 415 } 416 } 417 rti = rti->rti_next; 418 } 419 #ifdef IGMP_DEBUG 420 printf("[igmp.c,_slowtimo] -- > exiting \n"); 421 #endif 422 splx(s); 423 } 424 425 static void 426 igmp_sendpkt(inm, type, addr) 427 struct in_multi *inm; 428 int type; 429 unsigned long addr; 430 { 431 struct mbuf *m; 432 struct igmp *igmp; 433 struct ip *ip; 434 struct ip_moptions *imo; 435 436 MGETHDR(m, M_DONTWAIT, MT_HEADER); 437 if (m == NULL) 438 return; 439 440 MALLOC(imo, struct ip_moptions *, sizeof *imo, M_IPMOPTS, M_DONTWAIT); 441 if (!imo) { 442 m_free(m); 443 return; 444 } 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 ip_output(m, router_alert, (struct route *)0, 0, imo); 478 479 FREE(imo, M_IPMOPTS); 480 ++igmpstat.igps_snd_reports; 481 } 482