2 * Copyright (c) 1988 Stephen Deering.
3 * Copyright (c) 1992, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * Stephen Deering of Stanford University.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
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 * 4. 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.
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
33 * @(#)igmp.c 8.1 (Berkeley) 7/19/93
38 * Internet Group Management Protocol (IGMP) routines.
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.
45 * MULTICAST Revision: 3.5.1.4
50 #include <sys/param.h>
51 #include <sys/systm.h>
53 #include <sys/malloc.h>
55 #include <sys/socket.h>
56 #include <sys/protosw.h>
57 #include <sys/kernel.h>
58 #include <sys/sysctl.h>
61 #include <net/route.h>
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>
71 #include <machine/in_cksum.h>
73 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
75 static struct router_info *find_rti(struct ifnet *ifp);
76 static void igmp_sendpkt(struct in_multi *, int, unsigned long);
78 static struct igmpstat igmpstat;
80 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, &igmpstat,
84 * igmp_mtx protects all mutable global variables in igmp.c, as well as
85 * the data fields in struct router_info. In general, a router_info
86 * structure will be valid as long as the referencing struct in_multi is
87 * valid, so no reference counting is used. We allow unlocked reads of
88 * router_info data when accessed via an in_multi read-only.
90 static struct mtx igmp_mtx;
91 static SLIST_HEAD(, router_info) router_info_head;
92 static int igmp_timers_are_running;
95 * XXXRW: can we define these such that these can be made const? In any
96 * case, these shouldn't be changed after igmp_init() and therefore don't
99 static u_long igmp_all_hosts_group;
100 static u_long igmp_all_rtrs_group;
102 static struct mbuf *router_alert;
103 static struct route igmprt;
106 #define IGMP_PRINTF(x) printf(x)
108 #define IGMP_PRINTF(x)
117 * To avoid byte-swapping the same value over and over again.
119 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
120 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
122 igmp_timers_are_running = 0;
125 * Construct a Router Alert option to use in outgoing packets
127 MGET(router_alert, M_DONTWAIT, MT_DATA);
128 ra = mtod(router_alert, struct ipoption *);
129 ra->ipopt_dst.s_addr = 0;
130 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */
131 ra->ipopt_list[1] = 0x04; /* 4 bytes long */
132 ra->ipopt_list[2] = 0x00;
133 ra->ipopt_list[3] = 0x00;
134 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
136 mtx_init(&igmp_mtx, "igmp_mtx", NULL, MTX_DEF);
137 SLIST_INIT(&router_info_head);
140 static struct router_info *
141 find_rti(struct ifnet *ifp)
143 struct router_info *rti;
145 mtx_assert(&igmp_mtx, MA_OWNED);
146 IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n");
147 SLIST_FOREACH(rti, &router_info_head, rti_list) {
148 if (rti->rti_ifp == ifp) {
150 "[igmp.c, _find_rti] --> found old entry \n");
154 MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT);
156 IGMP_PRINTF( "[igmp.c, _find_rti] --> no memory for entry\n");
160 rti->rti_type = IGMP_V2_ROUTER;
162 SLIST_INSERT_HEAD(&router_info_head, rti, rti_list);
164 IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n");
169 igmp_input(register struct mbuf *m, int off)
171 register int iphlen = off;
172 register struct igmp *igmp;
173 register struct ip *ip;
174 register int igmplen;
175 register struct ifnet *ifp = m->m_pkthdr.rcvif;
177 register struct in_multi *inm;
178 register struct in_ifaddr *ia;
179 struct in_multistep step;
180 struct router_info *rti;
181 int timer; /** timer value in the igmp query header **/
183 ++igmpstat.igps_rcv_total;
185 ip = mtod(m, struct ip *);
186 igmplen = ip->ip_len;
191 if (igmplen < IGMP_MINLEN) {
192 ++igmpstat.igps_rcv_tooshort;
196 minlen = iphlen + IGMP_MINLEN;
197 if ((m->m_flags & M_EXT || m->m_len < minlen) &&
198 (m = m_pullup(m, minlen)) == 0) {
199 ++igmpstat.igps_rcv_tooshort;
208 igmp = mtod(m, struct igmp *);
209 if (in_cksum(m, igmplen)) {
210 ++igmpstat.igps_rcv_badsum;
217 ip = mtod(m, struct ip *);
218 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
223 * In the IGMPv2 specification, there are 3 states and a flag.
225 * In Non-Member state, we simply don't have a membership record.
226 * In Delaying Member state, our timer is running (inm->inm_timer)
227 * In Idle Member state, our timer is not running (inm->inm_timer==0)
229 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
230 * we have heard a report from another member, or IGMP_IREPORTEDLAST
231 * if I sent the last report.
233 switch (igmp->igmp_type) {
234 case IGMP_MEMBERSHIP_QUERY:
235 ++igmpstat.igps_rcv_queries;
237 if (ifp->if_flags & IFF_LOOPBACK)
240 if (igmp->igmp_code == 0) {
242 * Old router. Remember that the querier on this
243 * interface is old, and set the timer to the
250 mtx_unlock(&igmp_mtx);
254 rti->rti_type = IGMP_V1_ROUTER;
256 mtx_unlock(&igmp_mtx);
258 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
260 if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
261 igmp->igmp_group.s_addr != 0) {
262 ++igmpstat.igps_rcv_badqueries;
268 * New router. Simply do the new validity check.
271 if (igmp->igmp_group.s_addr != 0 &&
272 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
273 ++igmpstat.igps_rcv_badqueries;
280 * - Start the timers in all of our membership records
281 * that the query applies to for the interface on
282 * which the query arrived excl. those that belong
283 * to the "all-hosts" group (224.0.0.1).
284 * - Restart any timer that is already running but has
285 * a value longer than the requested timeout.
286 * - Use the value specified in the query message as
287 * the maximum timeout.
290 IN_FIRST_MULTI(step, inm);
291 while (inm != NULL) {
292 if (inm->inm_ifp == ifp &&
293 inm->inm_addr.s_addr != igmp_all_hosts_group &&
294 (igmp->igmp_group.s_addr == 0 ||
295 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
296 if (inm->inm_timer == 0 ||
297 inm->inm_timer > timer) {
299 IGMP_RANDOM_DELAY(timer);
300 igmp_timers_are_running = 1;
303 IN_NEXT_MULTI(step, inm);
309 case IGMP_V1_MEMBERSHIP_REPORT:
310 case IGMP_V2_MEMBERSHIP_REPORT:
312 * For fast leave to work, we have to know that we are the
313 * last person to send a report for this group. Reports
314 * can potentially get looped back if we are a multicast
315 * router, so discard reports sourced by me.
318 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
321 ++igmpstat.igps_rcv_reports;
323 if (ifp->if_flags & IFF_LOOPBACK)
326 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
327 ++igmpstat.igps_rcv_badreports;
333 * KLUDGE: if the IP source address of the report has an
334 * unspecified (i.e., zero) subnet number, as is allowed for
335 * a booting host, replace it with the correct subnet number
336 * so that a process-level multicast routing daemon can
337 * determine which subnet it arrived from. This is necessary
338 * to compensate for the lack of any way for a process to
339 * determine the arrival interface of an incoming packet.
341 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
342 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
345 * If we belong to the group being reported, stop
346 * our timer for that group.
349 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
352 ++igmpstat.igps_rcv_ourreports;
354 inm->inm_state = IGMP_OTHERMEMBER;
362 * Pass all valid IGMP packets up to any process(es) listening
363 * on a raw IGMP socket.
369 igmp_joingroup(struct in_multi *inm)
372 IN_MULTI_LOCK_ASSERT();
374 if (inm->inm_addr.s_addr == igmp_all_hosts_group
375 || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
377 inm->inm_state = IGMP_OTHERMEMBER;
380 inm->inm_rti = find_rti(inm->inm_ifp);
381 mtx_unlock(&igmp_mtx);
382 if (inm->inm_rti != NULL) {
383 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
384 inm->inm_timer = IGMP_RANDOM_DELAY(
385 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
386 inm->inm_state = IGMP_IREPORTEDLAST;
387 igmp_timers_are_running = 1;
389 /* XXX handling of failure case? */
394 igmp_leavegroup(struct in_multi *inm)
397 IN_MULTI_LOCK_ASSERT();
399 if (inm->inm_state == IGMP_IREPORTEDLAST &&
400 inm->inm_addr.s_addr != igmp_all_hosts_group &&
401 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
402 inm->inm_rti->rti_type != IGMP_V1_ROUTER)
403 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
409 register struct in_multi *inm;
410 struct in_multistep step;
413 * Quick check to see if any work needs to be done, in order
414 * to minimize the overhead of fasttimo processing.
417 if (!igmp_timers_are_running)
421 igmp_timers_are_running = 0;
422 IN_FIRST_MULTI(step, inm);
423 while (inm != NULL) {
424 if (inm->inm_timer == 0) {
426 } else if (--inm->inm_timer == 0) {
427 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
428 inm->inm_state = IGMP_IREPORTEDLAST;
430 igmp_timers_are_running = 1;
432 IN_NEXT_MULTI(step, inm);
440 struct router_info *rti;
442 IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n");
444 SLIST_FOREACH(rti, &router_info_head, rti_list) {
445 if (rti->rti_type == IGMP_V1_ROUTER) {
447 if (rti->rti_time >= IGMP_AGE_THRESHOLD)
448 rti->rti_type = IGMP_V2_ROUTER;
451 mtx_unlock(&igmp_mtx);
452 IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n");
456 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr)
461 struct ip_moptions imo;
463 IN_MULTI_LOCK_ASSERT();
465 MGETHDR(m, M_DONTWAIT, MT_HEADER);
469 m->m_pkthdr.rcvif = loif;
471 mac_create_mbuf_linklayer(inm->inm_ifp, m);
473 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
474 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
475 m->m_data += sizeof(struct ip);
476 m->m_len = IGMP_MINLEN;
477 igmp = mtod(m, struct igmp *);
478 igmp->igmp_type = type;
480 igmp->igmp_group = inm->inm_addr;
481 igmp->igmp_cksum = 0;
482 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN);
484 m->m_data -= sizeof(struct ip);
485 m->m_len += sizeof(struct ip);
486 ip = mtod(m, struct ip *);
488 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN;
490 ip->ip_p = IPPROTO_IGMP;
491 ip->ip_src.s_addr = INADDR_ANY;
492 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
494 imo.imo_multicast_ifp = inm->inm_ifp;
495 imo.imo_multicast_ttl = 1;
496 imo.imo_multicast_vif = -1;
498 * Request loopback of the report if we are acting as a multicast
499 * router, so that the process-level routing daemon can hear it.
501 imo.imo_multicast_loop = (ip_mrouter != NULL);
505 * Do we have to worry about reentrancy here? Don't think so.
507 ip_output(m, router_alert, &igmprt, 0, &imo, NULL);
509 ++igmpstat.igps_snd_reports;