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: head/sys/netinet/igmp.c 107022 2002-11-17 17:04:19Z luigi $
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 "opt_mac.h"
53
54#include <sys/param.h>
55#include <sys/systm.h>
56#include <sys/mac.h>
57#include <sys/malloc.h>
58#include <sys/mbuf.h>
59#include <sys/socket.h>
60#include <sys/protosw.h>
61#include <sys/kernel.h>
62#include <sys/sysctl.h>
63
64#include <net/if.h>
65#include <net/route.h>
66
67#include <netinet/in.h>
68#include <netinet/in_var.h>
69#include <netinet/in_systm.h>
70#include <netinet/ip.h>
71#include <netinet/ip_var.h>
72#include <netinet/igmp.h>
73#include <netinet/igmp_var.h>
74
75#include <machine/in_cksum.h>
76
77static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
78
79static struct router_info *find_rti(struct ifnet *ifp);
80
81static struct igmpstat igmpstat;
82
83SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW,
84 &igmpstat, igmpstat, "");
85
86static int igmp_timers_are_running;
87static u_long igmp_all_hosts_group;
88static u_long igmp_all_rtrs_group;
89static struct mbuf *router_alert;
90static struct router_info *Head;
91
92static void igmp_sendpkt(struct in_multi *, int, unsigned long);
93
94void
95igmp_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, M_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 = (struct router_info *) 0;
120}
121
122static struct router_info *
123find_rti(struct ifnet *ifp)
124{
125 struct router_info *rti = Head;
126
127#ifdef IGMP_DEBUG
128 printf("[igmp.c, _find_rti] --> entering \n");
129#endif
130 while (rti) {
131 if (rti->rti_ifp == ifp) {
132#ifdef IGMP_DEBUG
133 printf("[igmp.c, _find_rti] --> found old entry \n");
134#endif
135 return rti;
136 }
137 rti = rti->rti_next;
138 }
139 MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT);
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 printf("[igmp.c, _find_rti] --> created an entry \n");
147#endif
148 return rti;
149}
150
151void
152igmp_input(struct mbuf *m, int off)
153{
154 int iphlen = off;
155 struct igmp *igmp;
156 struct ip *ip;
157 int igmplen;
158 struct ifnet *ifp = m->m_pkthdr.rcvif;
159 int minlen;
160 struct in_multi *inm;
161 struct in_ifaddr *ia;
162 struct in_multistep step;
163 struct router_info *rti;
164
165 int timer; /** timer value in the igmp query header **/
166
167 ++igmpstat.igps_rcv_total;
168
169 ip = mtod(m, struct ip *);
170 igmplen = ip->ip_len;
171
172 /*
173 * Validate lengths
174 */
175 if (igmplen < IGMP_MINLEN) {
176 ++igmpstat.igps_rcv_tooshort;
177 m_freem(m);
178 return;
179 }
180 minlen = iphlen + IGMP_MINLEN;
181 if ((m->m_flags & M_EXT || m->m_len < minlen) &&
182 (m = m_pullup(m, minlen)) == 0) {
183 ++igmpstat.igps_rcv_tooshort;
184 return;
185 }
186
187 /*
188 * Validate checksum
189 */
190 m->m_data += iphlen;
191 m->m_len -= iphlen;
192 igmp = mtod(m, struct igmp *);
193 if (in_cksum(m, igmplen)) {
194 ++igmpstat.igps_rcv_badsum;
195 m_freem(m);
196 return;
197 }
198 m->m_data -= iphlen;
199 m->m_len += iphlen;
200
201 ip = mtod(m, struct ip *);
202 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
203 if (timer == 0)
204 timer = 1;
205 rti = find_rti(ifp);
206
207 /*
208 * In the IGMPv2 specification, there are 3 states and a flag.
209 *
210 * In Non-Member state, we simply don't have a membership record.
211 * In Delaying Member state, our timer is running (inm->inm_timer)
212 * In Idle Member state, our timer is not running (inm->inm_timer==0)
213 *
214 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
215 * we have heard a report from another member, or IGMP_IREPORTEDLAST
216 * if I sent the last report.
217 */
218 switch (igmp->igmp_type) {
219
220 case IGMP_MEMBERSHIP_QUERY:
221 ++igmpstat.igps_rcv_queries;
222
223 if (ifp->if_flags & IFF_LOOPBACK)
224 break;
225
226 if (igmp->igmp_code == 0) {
227 /*
228 * Old router. Remember that the querier on this
229 * interface is old, and set the timer to the
230 * value in RFC 1112.
231 */
232
233 rti->rti_type = IGMP_V1_ROUTER;
234 rti->rti_time = 0;
235
236 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
237
238 if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
239 igmp->igmp_group.s_addr != 0) {
240 ++igmpstat.igps_rcv_badqueries;
241 m_freem(m);
242 return;
243 }
244 } else {
245 /*
246 * New router. Simply do the new validity check.
247 */
248
249 if (igmp->igmp_group.s_addr != 0 &&
250 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
251 ++igmpstat.igps_rcv_badqueries;
252 m_freem(m);
253 return;
254 }
255 }
256
257 /*
258 * - Start the timers in all of our membership records
259 * that the query applies to for the interface on
260 * which the query arrived excl. those that belong
261 * to the "all-hosts" group (224.0.0.1).
262 * - Restart any timer that is already running but has
263 * a value longer than the requested timeout.
264 * - Use the value specified in the query message as
265 * the maximum timeout.
266 */
267 IN_FIRST_MULTI(step, inm);
268 while (inm != NULL) {
269 if (inm->inm_ifp == ifp &&
270 inm->inm_addr.s_addr != igmp_all_hosts_group &&
271 (igmp->igmp_group.s_addr == 0 ||
272 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
273 if (inm->inm_timer == 0 ||
274 inm->inm_timer > timer) {
275 inm->inm_timer =
276 IGMP_RANDOM_DELAY(timer);
277 igmp_timers_are_running = 1;
278 }
279 }
280 IN_NEXT_MULTI(step, inm);
281 }
282
283 break;
284
285 case IGMP_V1_MEMBERSHIP_REPORT:
286 case IGMP_V2_MEMBERSHIP_REPORT:
287 /*
288 * For fast leave to work, we have to know that we are the
289 * last person to send a report for this group. Reports
290 * can potentially get looped back if we are a multicast
291 * router, so discard reports sourced by me.
292 */
293 IFP_TO_IA(ifp, ia);
294 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
295 break;
296
297 ++igmpstat.igps_rcv_reports;
298
299 if (ifp->if_flags & IFF_LOOPBACK)
300 break;
301
302 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
303 ++igmpstat.igps_rcv_badreports;
304 m_freem(m);
305 return;
306 }
307
308 /*
309 * KLUDGE: if the IP source address of the report has an
310 * unspecified (i.e., zero) subnet number, as is allowed for
311 * a booting host, replace it with the correct subnet number
312 * so that a process-level multicast routing daemon can
313 * determine which subnet it arrived from. This is necessary
314 * to compensate for the lack of any way for a process to
315 * determine the arrival interface of an incoming packet.
316 */
317 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
318 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
319
320 /*
321 * If we belong to the group being reported, stop
322 * our timer for that group.
323 */
324 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
325
326 if (inm != NULL) {
327 inm->inm_timer = 0;
328 ++igmpstat.igps_rcv_ourreports;
329
330 inm->inm_state = IGMP_OTHERMEMBER;
331 }
332
333 break;
334 }
335
336 /*
337 * Pass all valid IGMP packets up to any process(es) listening
338 * on a raw IGMP socket.
339 */
340 rip_input(m, off);
341}
342
343void
344igmp_joingroup(struct in_multi *inm)
345{
346 int s = splnet();
347
348 if (inm->inm_addr.s_addr == igmp_all_hosts_group
349 || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
350 inm->inm_timer = 0;
351 inm->inm_state = IGMP_OTHERMEMBER;
352 } else {
353 inm->inm_rti = find_rti(inm->inm_ifp);
354 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
355 inm->inm_timer = IGMP_RANDOM_DELAY(
356 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
357 inm->inm_state = IGMP_IREPORTEDLAST;
358 igmp_timers_are_running = 1;
359 }
360 splx(s);
361}
362
363void
364igmp_leavegroup(struct in_multi *inm)
365{
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);
371}
372
373void
374igmp_fasttimo(void)
375{
376 struct in_multi *inm;
377 struct in_multistep step;
378 int s;
379
380 /*
381 * Quick check to see if any work needs to be done, in order
382 * to minimize the overhead of fasttimo processing.
383 */
384
385 if (!igmp_timers_are_running)
386 return;
387
388 s = splnet();
389 igmp_timers_are_running = 0;
390 IN_FIRST_MULTI(step, inm);
391 while (inm != NULL) {
392 if (inm->inm_timer == 0) {
393 /* do nothing */
394 } else if (--inm->inm_timer == 0) {
395 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
396 inm->inm_state = IGMP_IREPORTEDLAST;
397 } else {
398 igmp_timers_are_running = 1;
399 }
400 IN_NEXT_MULTI(step, inm);
401 }
402 splx(s);
403}
404
405void
406igmp_slowtimo(void)
407{
408 int s = splnet();
409 struct router_info *rti = Head;
410
411#ifdef IGMP_DEBUG
412 printf("[igmp.c,_slowtimo] -- > entering \n");
413#endif
414 while (rti) {
415 if (rti->rti_type == IGMP_V1_ROUTER) {
416 rti->rti_time++;
417 if (rti->rti_time >= IGMP_AGE_THRESHOLD) {
418 rti->rti_type = IGMP_V2_ROUTER;
419 }
420 }
421 rti = rti->rti_next;
422 }
423#ifdef IGMP_DEBUG
424 printf("[igmp.c,_slowtimo] -- > exiting \n");
425#endif
426 splx(s);
427}
428
429/*
430 * XXX fix this static var when we remove the network code from Giant.
431 */
432static struct route igmprt;
433
434static void
435igmp_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, M_DONTWAIT, MT_HEADER);
443 if (m == NULL)
444 return;
445
446 m->m_pkthdr.rcvif = loif;
447#ifdef MAC
448 mac_create_mbuf_linklayer(inm->inm_ifp, m);
449#endif
450 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
451 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
452 m->m_data += sizeof(struct ip);
453 m->m_len = IGMP_MINLEN;
454 igmp = mtod(m, struct igmp *);
455 igmp->igmp_type = type;
456 igmp->igmp_code = 0;
457 igmp->igmp_group = inm->inm_addr;
458 igmp->igmp_cksum = 0;
459 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN);
460
461 m->m_data -= sizeof(struct ip);
462 m->m_len += sizeof(struct ip);
463 ip = mtod(m, struct ip *);
464 ip->ip_tos = 0;
465 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN;
466 ip->ip_off = 0;
467 ip->ip_p = IPPROTO_IGMP;
468 ip->ip_src.s_addr = INADDR_ANY;
469 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
470
471 imo.imo_multicast_ifp = inm->inm_ifp;
472 imo.imo_multicast_ttl = 1;
473 imo.imo_multicast_vif = -1;
474 /*
475 * Request loopback of the report if we are acting as a multicast
476 * router, so that the process-level routing daemon can hear it.
477 */
478 imo.imo_multicast_loop = (ip_mrouter != NULL);
479
480 /*
481 * XXX
482 * Do we have to worry about reentrancy here? Don't think so.
483 */
484 ip_output(m, router_alert, &igmprt, 0, &imo, NULL);
485
486 ++igmpstat.igps_snd_reports;
487}