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
37 * Internet Group Management Protocol (IGMP) routines.
39 * Written by Steve Deering, Stanford, May 1988.
40 * Modified by Rosen Sharma, Stanford, Aug 1994.
41 * Modified by Bill Fenner, Xerox PARC, Feb 1995.
42 * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995.
44 * MULTICAST Revision: 3.5.1.4
47 #include <sys/cdefs.h>
48 __FBSDID("$FreeBSD$");
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>
60 #include <sys/vimage.h>
63 #include <net/route.h>
65 #include <netinet/in.h>
66 #include <netinet/in_var.h>
67 #include <netinet/in_systm.h>
68 #include <netinet/ip.h>
69 #include <netinet/ip_var.h>
70 #include <netinet/ip_options.h>
71 #include <netinet/igmp.h>
72 #include <netinet/igmp_var.h>
74 #include <machine/in_cksum.h>
76 #include <security/mac/mac_framework.h>
78 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
80 static struct router_info *find_rti(struct ifnet *ifp);
81 static void igmp_sendpkt(struct in_multi *, int, unsigned long);
83 static struct igmpstat igmpstat;
85 SYSCTL_V_STRUCT(V_NET, vnet_inet, _net_inet_igmp, IGMPCTL_STATS,
86 stats, CTLFLAG_RW, igmpstat, igmpstat, "");
89 * igmp_mtx protects all mutable global variables in igmp.c, as well as the
90 * data fields in struct router_info. In general, a router_info structure
91 * will be valid as long as the referencing struct in_multi is valid, so no
92 * reference counting is used. We allow unlocked reads of router_info data
93 * when accessed via an in_multi read-only.
95 static struct mtx igmp_mtx;
96 static SLIST_HEAD(, router_info) router_info_head;
97 static int igmp_timers_are_running;
100 * XXXRW: can we define these such that these can be made const? In any
101 * case, these shouldn't be changed after igmp_init() and therefore don't
104 static u_long igmp_all_hosts_group;
105 static u_long igmp_all_rtrs_group;
107 static struct mbuf *router_alert;
108 static struct route igmprt;
111 #define IGMP_PRINTF(x) printf(x)
113 #define IGMP_PRINTF(x)
119 INIT_VNET_INET(curvnet);
123 * To avoid byte-swapping the same value over and over again.
125 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
126 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
128 igmp_timers_are_running = 0;
131 * Construct a Router Alert option to use in outgoing packets.
133 MGET(router_alert, M_DONTWAIT, MT_DATA);
134 ra = mtod(router_alert, struct ipoption *);
135 ra->ipopt_dst.s_addr = 0;
136 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */
137 ra->ipopt_list[1] = 0x04; /* 4 bytes long */
138 ra->ipopt_list[2] = 0x00;
139 ra->ipopt_list[3] = 0x00;
140 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
142 mtx_init(&igmp_mtx, "igmp_mtx", NULL, MTX_DEF);
143 SLIST_INIT(&V_router_info_head);
146 static struct router_info *
147 find_rti(struct ifnet *ifp)
149 INIT_VNET_INET(ifp->if_vnet);
150 struct router_info *rti;
152 mtx_assert(&igmp_mtx, MA_OWNED);
153 IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n");
154 SLIST_FOREACH(rti, &V_router_info_head, rti_list) {
155 if (rti->rti_ifp == ifp) {
157 "[igmp.c, _find_rti] --> found old entry \n");
161 MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT);
163 IGMP_PRINTF("[igmp.c, _find_rti] --> no memory for entry\n");
167 rti->rti_type = IGMP_V2_ROUTER;
169 SLIST_INSERT_HEAD(&V_router_info_head, rti, rti_list);
170 IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n");
175 igmp_input(register struct mbuf *m, int off)
177 register int iphlen = off;
178 register struct igmp *igmp;
179 register struct ip *ip;
180 register int igmplen;
181 register struct ifnet *ifp = m->m_pkthdr.rcvif;
183 register struct in_multi *inm;
184 register struct in_ifaddr *ia;
185 struct in_multistep step;
186 struct router_info *rti;
187 int timer; /** timer value in the igmp query header **/
188 INIT_VNET_INET(ifp->if_vnet);
190 ++V_igmpstat.igps_rcv_total;
192 ip = mtod(m, struct ip *);
193 igmplen = ip->ip_len;
198 if (igmplen < IGMP_MINLEN) {
199 ++V_igmpstat.igps_rcv_tooshort;
203 minlen = iphlen + IGMP_MINLEN;
204 if ((m->m_flags & M_EXT || m->m_len < minlen) &&
205 (m = m_pullup(m, minlen)) == 0) {
206 ++V_igmpstat.igps_rcv_tooshort;
215 igmp = mtod(m, struct igmp *);
216 if (in_cksum(m, igmplen)) {
217 ++V_igmpstat.igps_rcv_badsum;
224 ip = mtod(m, struct ip *);
225 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
230 * In the IGMPv2 specification, there are 3 states and a flag.
232 * In Non-Member state, we simply don't have a membership record.
233 * In Delaying Member state, our timer is running (inm->inm_timer).
234 * In Idle Member state, our timer is not running (inm->inm_timer==0).
236 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if we
237 * have heard a report from another member, or IGMP_IREPORTEDLAST if
238 * I sent the last report.
240 switch (igmp->igmp_type) {
241 case IGMP_MEMBERSHIP_QUERY:
242 ++V_igmpstat.igps_rcv_queries;
244 if (ifp->if_flags & IFF_LOOPBACK)
247 if (igmp->igmp_code == 0) {
249 * Old router. Remember that the querier on this
250 * interface is old, and set the timer to the value
257 mtx_unlock(&igmp_mtx);
261 rti->rti_type = IGMP_V1_ROUTER;
263 mtx_unlock(&igmp_mtx);
265 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
267 if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
268 igmp->igmp_group.s_addr != 0) {
269 ++V_igmpstat.igps_rcv_badqueries;
275 * New router. Simply do the new validity check.
278 if (igmp->igmp_group.s_addr != 0 &&
279 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
280 ++V_igmpstat.igps_rcv_badqueries;
287 * - Start the timers in all of our membership records that
288 * the query applies to for the interface on which the
289 * query arrived excl. those that belong to the "all-hosts"
291 * - Restart any timer that is already running but has a
292 * value longer than the requested timeout.
293 * - Use the value specified in the query message as the
297 IN_FIRST_MULTI(step, inm);
298 while (inm != NULL) {
299 if (inm->inm_ifp == ifp &&
300 inm->inm_addr.s_addr != igmp_all_hosts_group &&
301 (igmp->igmp_group.s_addr == 0 ||
302 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
303 if (inm->inm_timer == 0 ||
304 inm->inm_timer > timer) {
306 IGMP_RANDOM_DELAY(timer);
307 igmp_timers_are_running = 1;
310 IN_NEXT_MULTI(step, inm);
315 case IGMP_V1_MEMBERSHIP_REPORT:
316 case IGMP_V2_MEMBERSHIP_REPORT:
318 * For fast leave to work, we have to know that we are the
319 * last person to send a report for this group. Reports can
320 * potentially get looped back if we are a multicast router,
321 * so discard reports sourced by me.
325 ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
328 ++V_igmpstat.igps_rcv_reports;
330 if (ifp->if_flags & IFF_LOOPBACK)
333 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
334 ++V_igmpstat.igps_rcv_badreports;
340 * KLUDGE: if the IP source address of the report has an
341 * unspecified (i.e., zero) subnet number, as is allowed for
342 * a booting host, replace it with the correct subnet number
343 * so that a process-level multicast routing daemon can
344 * determine which subnet it arrived from. This is necessary
345 * to compensate for the lack of any way for a process to
346 * determine the arrival interface of an incoming packet.
348 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) {
350 ip->ip_src.s_addr = htonl(ia->ia_subnet);
354 * If we belong to the group being reported, stop our timer
358 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
361 ++V_igmpstat.igps_rcv_ourreports;
362 inm->inm_state = IGMP_OTHERMEMBER;
369 * Pass all valid IGMP packets up to any process(es) listening on a
376 igmp_joingroup(struct in_multi *inm)
379 IN_MULTI_LOCK_ASSERT();
381 if (inm->inm_addr.s_addr == igmp_all_hosts_group
382 || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
384 inm->inm_state = IGMP_OTHERMEMBER;
387 inm->inm_rti = find_rti(inm->inm_ifp);
388 mtx_unlock(&igmp_mtx);
389 if (inm->inm_rti != NULL) {
390 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
391 inm->inm_timer = IGMP_RANDOM_DELAY(
392 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
393 inm->inm_state = IGMP_IREPORTEDLAST;
394 igmp_timers_are_running = 1;
396 /* XXX handling of failure case? */
401 igmp_leavegroup(struct in_multi *inm)
404 IN_MULTI_LOCK_ASSERT();
406 if (inm->inm_state == IGMP_IREPORTEDLAST &&
407 inm->inm_addr.s_addr != igmp_all_hosts_group &&
408 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
409 inm->inm_rti->rti_type != IGMP_V1_ROUTER)
410 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
416 VNET_ITERATOR_DECL(vnet_iter);
417 register struct in_multi *inm;
418 struct in_multistep step;
421 * Quick check to see if any work needs to be done, in order to
422 * minimize the overhead of fasttimo processing.
425 if (!igmp_timers_are_running)
429 igmp_timers_are_running = 0;
431 VNET_FOREACH(vnet_iter) {
432 CURVNET_SET(vnet_iter);
433 INIT_VNET_INET(vnet_iter);
434 IN_FIRST_MULTI(step, inm);
435 while (inm != NULL) {
436 if (inm->inm_timer == 0) {
438 } else if (--inm->inm_timer == 0) {
439 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
440 inm->inm_state = IGMP_IREPORTEDLAST;
442 igmp_timers_are_running = 1;
444 IN_NEXT_MULTI(step, inm);
455 VNET_ITERATOR_DECL(vnet_iter);
456 struct router_info *rti;
458 IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n");
461 VNET_FOREACH(vnet_iter) {
462 CURVNET_SET(vnet_iter);
463 INIT_VNET_INET(vnet_iter);
464 SLIST_FOREACH(rti, &V_router_info_head, rti_list) {
465 if (rti->rti_type == IGMP_V1_ROUTER) {
467 if (rti->rti_time >= IGMP_AGE_THRESHOLD)
468 rti->rti_type = IGMP_V2_ROUTER;
474 mtx_unlock(&igmp_mtx);
475 IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n");
479 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr)
481 INIT_VNET_NET(curvnet);
482 INIT_VNET_INET(curvnet);
486 struct ip_moptions imo;
488 IN_MULTI_LOCK_ASSERT();
490 MGETHDR(m, M_DONTWAIT, MT_DATA);
494 m->m_pkthdr.rcvif = V_loif;
496 mac_netinet_igmp_send(inm->inm_ifp, m);
498 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
499 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
500 m->m_data += sizeof(struct ip);
501 m->m_len = IGMP_MINLEN;
502 igmp = mtod(m, struct igmp *);
503 igmp->igmp_type = type;
505 igmp->igmp_group = inm->inm_addr;
506 igmp->igmp_cksum = 0;
507 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN);
509 m->m_data -= sizeof(struct ip);
510 m->m_len += sizeof(struct ip);
511 ip = mtod(m, struct ip *);
513 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN;
515 ip->ip_p = IPPROTO_IGMP;
516 ip->ip_src.s_addr = INADDR_ANY;
517 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
519 imo.imo_multicast_ifp = inm->inm_ifp;
520 imo.imo_multicast_ttl = 1;
521 imo.imo_multicast_vif = -1;
523 * Request loopback of the report if we are acting as a multicast
524 * router, so that the process-level routing daemon can hear it.
526 imo.imo_multicast_loop = (V_ip_mrouter != NULL);
529 * XXX: Do we have to worry about reentrancy here? Don't think so.
531 ip_output(m, router_alert, &igmprt, 0, &imo, NULL);
533 ++V_igmpstat.igps_snd_reports;