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 * 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.
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
37 * @(#)igmp.c 8.1 (Berkeley) 7/19/93
42 * Internet Group Management Protocol (IGMP) routines.
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.
49 * MULTICAST Revision: 3.5.1.4
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/malloc.h>
56 #include <sys/socket.h>
57 #include <sys/protosw.h>
58 #include <sys/kernel.h>
59 #include <sys/sysctl.h>
62 #include <net/route.h>
64 #include <netinet/in.h>
65 #include <netinet/in_var.h>
66 #include <netinet/in_systm.h>
67 #include <netinet/ip.h>
68 #include <netinet/ip_var.h>
69 #include <netinet/igmp.h>
70 #include <netinet/igmp_var.h>
72 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
74 static struct router_info *
75 find_rti __P((struct ifnet *ifp));
77 static struct igmpstat igmpstat;
79 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD,
80 &igmpstat, igmpstat, "");
82 static int igmp_timers_are_running;
83 static u_long igmp_all_hosts_group;
84 static u_long igmp_all_rtrs_group;
85 static struct mbuf *router_alert;
86 static struct router_info *Head;
88 static void igmp_sendpkt __P((struct in_multi *, int, unsigned long));
96 * To avoid byte-swapping the same value over and over again.
98 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
99 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
101 igmp_timers_are_running = 0;
104 * Construct a Router Alert option to use in outgoing packets
106 MGET(router_alert, M_DONTWAIT, MT_DATA);
107 ra = mtod(router_alert, struct ipoption *);
108 ra->ipopt_dst.s_addr = 0;
109 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */
110 ra->ipopt_list[1] = 0x04; /* 4 bytes long */
111 ra->ipopt_list[2] = 0x00;
112 ra->ipopt_list[3] = 0x00;
113 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
115 Head = (struct router_info *) 0;
118 static struct router_info *
122 register struct router_info *rti = Head;
125 printf("[igmp.c, _find_rti] --> entering \n");
128 if (rti->rti_ifp == ifp) {
130 printf("[igmp.c, _find_rti] --> found old entry \n");
136 MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT);
138 rti->rti_type = IGMP_V2_ROUTER;
140 rti->rti_next = Head;
143 printf("[igmp.c, _find_rti] --> created an entry \n");
149 igmp_input(m, iphlen)
150 register struct mbuf *m;
153 register struct igmp *igmp;
154 register struct ip *ip;
155 register int igmplen;
156 register struct ifnet *ifp = m->m_pkthdr.rcvif;
158 register struct in_multi *inm;
159 register struct in_ifaddr *ia;
160 struct in_multistep step;
161 struct router_info *rti;
163 int timer; /** timer value in the igmp query header **/
165 ++igmpstat.igps_rcv_total;
167 ip = mtod(m, struct ip *);
168 igmplen = ip->ip_len;
173 if (igmplen < IGMP_MINLEN) {
174 ++igmpstat.igps_rcv_tooshort;
178 minlen = iphlen + IGMP_MINLEN;
179 if ((m->m_flags & M_EXT || m->m_len < minlen) &&
180 (m = m_pullup(m, minlen)) == 0) {
181 ++igmpstat.igps_rcv_tooshort;
190 igmp = mtod(m, struct igmp *);
191 if (in_cksum(m, igmplen)) {
192 ++igmpstat.igps_rcv_badsum;
199 ip = mtod(m, struct ip *);
200 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
206 * In the IGMPv2 specification, there are 3 states and a flag.
208 * In Non-Member state, we simply don't have a membership record.
209 * In Delaying Member state, our timer is running (inm->inm_timer)
210 * In Idle Member state, our timer is not running (inm->inm_timer==0)
212 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
213 * we have heard a report from another member, or IGMP_IREPORTEDLAST
214 * if I sent the last report.
216 switch (igmp->igmp_type) {
218 case IGMP_MEMBERSHIP_QUERY:
219 ++igmpstat.igps_rcv_queries;
221 if (ifp->if_flags & IFF_LOOPBACK)
224 if (igmp->igmp_code == 0) {
226 * Old router. Remember that the querier on this
227 * interface is old, and set the timer to the
231 rti->rti_type = IGMP_V1_ROUTER;
234 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
236 if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
237 igmp->igmp_group.s_addr != 0) {
238 ++igmpstat.igps_rcv_badqueries;
244 * New router. Simply do the new validity check.
247 if (igmp->igmp_group.s_addr != 0 &&
248 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
249 ++igmpstat.igps_rcv_badqueries;
256 * - Start the timers in all of our membership records
257 * that the query applies to for the interface on
258 * which the query arrived excl. those that belong
259 * to the "all-hosts" group (224.0.0.1).
260 * - Restart any timer that is already running but has
261 * a value longer than the requested timeout.
262 * - Use the value specified in the query message as
263 * the maximum timeout.
265 IN_FIRST_MULTI(step, inm);
266 while (inm != NULL) {
267 if (inm->inm_ifp == ifp &&
268 inm->inm_addr.s_addr != igmp_all_hosts_group &&
269 (igmp->igmp_group.s_addr == 0 ||
270 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
271 if (inm->inm_timer == 0 ||
272 inm->inm_timer > timer) {
274 IGMP_RANDOM_DELAY(timer);
275 igmp_timers_are_running = 1;
278 IN_NEXT_MULTI(step, inm);
283 case IGMP_V1_MEMBERSHIP_REPORT:
284 case IGMP_V2_MEMBERSHIP_REPORT:
286 * For fast leave to work, we have to know that we are the
287 * last person to send a report for this group. Reports
288 * can potentially get looped back if we are a multicast
289 * router, so discard reports sourced by me.
292 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
295 ++igmpstat.igps_rcv_reports;
297 if (ifp->if_flags & IFF_LOOPBACK)
300 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
301 ++igmpstat.igps_rcv_badreports;
307 * KLUDGE: if the IP source address of the report has an
308 * unspecified (i.e., zero) subnet number, as is allowed for
309 * a booting host, replace it with the correct subnet number
310 * so that a process-level multicast routing demon can
311 * determine which subnet it arrived from. This is necessary
312 * to compensate for the lack of any way for a process to
313 * determine the arrival interface of an incoming packet.
315 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
316 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
319 * If we belong to the group being reported, stop
320 * our timer for that group.
322 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
326 ++igmpstat.igps_rcv_ourreports;
328 inm->inm_state = IGMP_OTHERMEMBER;
335 * Pass all valid IGMP packets up to any process(es) listening
336 * on a raw IGMP socket.
338 rip_input(m, iphlen);
343 struct in_multi *inm;
347 if (inm->inm_addr.s_addr == igmp_all_hosts_group
348 || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
350 inm->inm_state = IGMP_OTHERMEMBER;
352 inm->inm_rti = find_rti(inm->inm_ifp);
353 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
354 inm->inm_timer = IGMP_RANDOM_DELAY(
355 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
356 inm->inm_state = IGMP_IREPORTEDLAST;
357 igmp_timers_are_running = 1;
364 struct in_multi *inm;
366 if (inm->inm_state == IGMP_IREPORTEDLAST &&
367 inm->inm_addr.s_addr != igmp_all_hosts_group &&
368 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
369 inm->inm_rti->rti_type != IGMP_V1_ROUTER)
370 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
376 register struct in_multi *inm;
377 struct in_multistep step;
381 * Quick check to see if any work needs to be done, in order
382 * to minimize the overhead of fasttimo processing.
385 if (!igmp_timers_are_running)
389 igmp_timers_are_running = 0;
390 IN_FIRST_MULTI(step, inm);
391 while (inm != NULL) {
392 if (inm->inm_timer == 0) {
394 } else if (--inm->inm_timer == 0) {
395 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
396 inm->inm_state = IGMP_IREPORTEDLAST;
398 igmp_timers_are_running = 1;
400 IN_NEXT_MULTI(step, inm);
409 register struct router_info *rti = Head;
412 printf("[igmp.c,_slowtimo] -- > entering \n");
415 if (rti->rti_type == IGMP_V1_ROUTER) {
417 if (rti->rti_time >= IGMP_AGE_THRESHOLD) {
418 rti->rti_type = IGMP_V2_ROUTER;
424 printf("[igmp.c,_slowtimo] -- > exiting \n");
429 static struct route igmprt;
432 igmp_sendpkt(inm, type, addr)
433 struct in_multi *inm;
440 struct ip_moptions imo;
442 MGETHDR(m, M_DONTWAIT, MT_HEADER);
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;
454 igmp->igmp_group = inm->inm_addr;
455 igmp->igmp_cksum = 0;
456 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN);
458 m->m_data -= sizeof(struct ip);
459 m->m_len += sizeof(struct ip);
460 ip = mtod(m, struct ip *);
462 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN;
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;
468 imo.imo_multicast_ifp = inm->inm_ifp;
469 imo.imo_multicast_ttl = 1;
470 imo.imo_multicast_vif = -1;
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.
475 imo.imo_multicast_loop = (ip_mrouter != NULL);
479 * Do we have to worry about reentrancy here? Don't think so.
481 ip_output(m, router_alert, &igmprt, 0, &imo);
483 ++igmpstat.igps_snd_reports;