xref: /netbsd/sys/netinet/igmp.c (revision 5886cd66)
1 /*	$NetBSD: igmp.c,v 1.70 2020/05/15 06:34:34 maxv Exp $	*/
2 
3 /*
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * Internet Group Management Protocol (IGMP) routines.
34  *
35  * Written by Steve Deering, Stanford, May 1988.
36  * Modified by Rosen Sharma, Stanford, Aug 1994.
37  * Modified by Bill Fenner, Xerox PARC, Feb 1995.
38  *
39  * MULTICAST Revision: 1.3
40  */
41 
42 #include <sys/cdefs.h>
43 __KERNEL_RCSID(0, "$NetBSD: igmp.c,v 1.70 2020/05/15 06:34:34 maxv Exp $");
44 
45 #ifdef _KERNEL_OPT
46 #include "opt_mrouting.h"
47 #include "opt_net_mpsafe.h"
48 #endif
49 
50 #include <sys/param.h>
51 #include <sys/mbuf.h>
52 #include <sys/socket.h>
53 #include <sys/socketvar.h>
54 #include <sys/systm.h>
55 #include <sys/cprng.h>
56 #include <sys/sysctl.h>
57 
58 #include <net/if.h>
59 #include <net/net_stats.h>
60 
61 #include <netinet/in.h>
62 #include <netinet/in_var.h>
63 #include <netinet/in_systm.h>
64 #include <netinet/ip.h>
65 #include <netinet/ip_var.h>
66 #include <netinet/igmp.h>
67 #include <netinet/igmp_var.h>
68 
69 /*
70  * Per-interface router version information.
71  */
72 typedef struct router_info {
73 	LIST_ENTRY(router_info) rti_link;
74 	ifnet_t *	rti_ifp;
75 	int		rti_type;	/* type of router on this interface */
76 	int		rti_age;	/* time since last v1 query */
77 } router_info_t;
78 
79 /*
80  * The router-info list and the timer flag are protected by in_multilock.
81  *
82  * Lock order:
83  *
84  *	softnet_lock ->
85  *		in_multilock
86  */
87 static struct pool	igmp_rti_pool		__cacheline_aligned;
88 static LIST_HEAD(, router_info)	rti_head	__cacheline_aligned;
89 static int		igmp_timers_on		__cacheline_aligned;
90 static percpu_t *	igmpstat_percpu		__read_mostly;
91 
92 #define	IGMP_STATINC(x)		_NET_STATINC(igmpstat_percpu, x)
93 
94 static void		igmp_sendpkt(struct in_multi *, int);
95 static int		rti_fill(struct in_multi *);
96 static router_info_t *	rti_find(struct ifnet *);
97 static void		rti_delete(struct ifnet *);
98 static void		sysctl_net_inet_igmp_setup(struct sysctllog **);
99 
100 /*
101  * rti_fill: associate router information with the given multicast group;
102  * if there is no router information for the interface, then create it.
103  */
104 static int
rti_fill(struct in_multi * inm)105 rti_fill(struct in_multi *inm)
106 {
107 	router_info_t *rti;
108 
109 	KASSERT(in_multi_lock_held());
110 
111 	LIST_FOREACH(rti, &rti_head, rti_link) {
112 		if (rti->rti_ifp == inm->inm_ifp) {
113 			inm->inm_rti = rti;
114 			return rti->rti_type == IGMP_v1_ROUTER ?
115 			    IGMP_v1_HOST_MEMBERSHIP_REPORT :
116 			    IGMP_v2_HOST_MEMBERSHIP_REPORT;
117 		}
118 	}
119 	rti = pool_get(&igmp_rti_pool, PR_NOWAIT);
120 	if (rti == NULL) {
121 		return 0;
122 	}
123 	rti->rti_ifp = inm->inm_ifp;
124 	rti->rti_type = IGMP_v2_ROUTER;
125 	LIST_INSERT_HEAD(&rti_head, rti, rti_link);
126 	inm->inm_rti = rti;
127 	return IGMP_v2_HOST_MEMBERSHIP_REPORT;
128 }
129 
130 /*
131  * rti_find: lookup or create router information for the given interface.
132  */
133 static router_info_t *
rti_find(ifnet_t * ifp)134 rti_find(ifnet_t *ifp)
135 {
136 	router_info_t *rti;
137 
138 	KASSERT(in_multi_lock_held());
139 
140 	LIST_FOREACH(rti, &rti_head, rti_link) {
141 		if (rti->rti_ifp == ifp)
142 			return rti;
143 	}
144 	rti = pool_get(&igmp_rti_pool, PR_NOWAIT);
145 	if (rti == NULL) {
146 		return NULL;
147 	}
148 	rti->rti_ifp = ifp;
149 	rti->rti_type = IGMP_v2_ROUTER;
150 	LIST_INSERT_HEAD(&rti_head, rti, rti_link);
151 	return rti;
152 }
153 
154 /*
155  * rti_delete: remove and free the router information entry for the
156  * given interface.
157  */
158 static void
rti_delete(ifnet_t * ifp)159 rti_delete(ifnet_t *ifp)
160 {
161 	router_info_t *rti;
162 
163 	KASSERT(in_multi_lock_held());
164 
165 	LIST_FOREACH(rti, &rti_head, rti_link) {
166 		if (rti->rti_ifp == ifp) {
167 			LIST_REMOVE(rti, rti_link);
168 			pool_put(&igmp_rti_pool, rti);
169 			break;
170 		}
171 	}
172 }
173 
174 void
igmp_init(void)175 igmp_init(void)
176 {
177 	pool_init(&igmp_rti_pool, sizeof(router_info_t), 0, 0, 0,
178 	    "igmppl", NULL, IPL_SOFTNET);
179 	igmpstat_percpu = percpu_alloc(sizeof(uint64_t) * IGMP_NSTATS);
180 	sysctl_net_inet_igmp_setup(NULL);
181 	LIST_INIT(&rti_head);
182 }
183 
184 void
igmp_input(struct mbuf * m,int off,int proto)185 igmp_input(struct mbuf *m, int off, int proto)
186 {
187 	ifnet_t *ifp;
188 	struct ip *ip = mtod(m, struct ip *);
189 	struct igmp *igmp;
190 	u_int minlen, timer;
191 	struct in_multi *inm;
192 	struct in_ifaddr *ia;
193 	int ip_len, iphlen;
194 	struct psref psref;
195 
196 	iphlen = off;
197 
198 	IGMP_STATINC(IGMP_STAT_RCV_TOTAL);
199 
200 	/*
201 	 * Validate lengths
202 	 */
203 	minlen = iphlen + IGMP_MINLEN;
204 	ip_len = ntohs(ip->ip_len);
205 	if (ip_len < minlen) {
206 		IGMP_STATINC(IGMP_STAT_RCV_TOOSHORT);
207 		m_freem(m);
208 		return;
209 	}
210 	if (((m->m_flags & M_EXT) && (ip->ip_src.s_addr & IN_CLASSA_NET) == 0)
211 	    || m->m_len < minlen) {
212 		if ((m = m_pullup(m, minlen)) == NULL) {
213 			IGMP_STATINC(IGMP_STAT_RCV_TOOSHORT);
214 			return;
215 		}
216 		ip = mtod(m, struct ip *);
217 	}
218 
219 	/*
220 	 * Validate checksum
221 	 */
222 	m->m_data += iphlen;
223 	m->m_len -= iphlen;
224 	igmp = mtod(m, struct igmp *);
225 	/* No need to assert alignment here. */
226 	if (in_cksum(m, ip_len - iphlen)) {
227 		IGMP_STATINC(IGMP_STAT_RCV_BADSUM);
228 		m_freem(m);
229 		return;
230 	}
231 	m->m_data -= iphlen;
232 	m->m_len += iphlen;
233 
234 	ifp = m_get_rcvif_psref(m, &psref);
235 	if (__predict_false(ifp == NULL))
236 		goto drop;
237 
238 	switch (igmp->igmp_type) {
239 
240 	case IGMP_HOST_MEMBERSHIP_QUERY:
241 		IGMP_STATINC(IGMP_STAT_RCV_QUERIES);
242 
243 		if (ifp->if_flags & IFF_LOOPBACK)
244 			break;
245 
246 		if (igmp->igmp_code == 0) {
247 			struct in_multistep step;
248 			router_info_t *rti;
249 
250 			if (ip->ip_dst.s_addr != INADDR_ALLHOSTS_GROUP) {
251 				IGMP_STATINC(IGMP_STAT_RCV_BADQUERIES);
252 				goto drop;
253 			}
254 
255 			in_multi_lock(RW_WRITER);
256 			rti = rti_find(ifp);
257 			if (rti == NULL) {
258 				in_multi_unlock();
259 				break;
260 			}
261 			rti->rti_type = IGMP_v1_ROUTER;
262 			rti->rti_age = 0;
263 
264 			/*
265 			 * Start the timers in all of our membership records
266 			 * for the interface on which the query arrived,
267 			 * except those that are already running and those
268 			 * that belong to a "local" group (224.0.0.X).
269 			 */
270 
271 			inm = in_first_multi(&step);
272 			while (inm != NULL) {
273 				if (inm->inm_ifp == ifp &&
274 				    inm->inm_timer == 0 &&
275 				    !IN_LOCAL_GROUP(inm->inm_addr.s_addr)) {
276 					inm->inm_state = IGMP_DELAYING_MEMBER;
277 					inm->inm_timer = IGMP_RANDOM_DELAY(
278 					    IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ);
279 					igmp_timers_on = true;
280 				}
281 				inm = in_next_multi(&step);
282 			}
283 			in_multi_unlock();
284 		} else {
285 			struct in_multistep step;
286 
287 			if (!IN_MULTICAST(ip->ip_dst.s_addr)) {
288 				IGMP_STATINC(IGMP_STAT_RCV_BADQUERIES);
289 				goto drop;
290 			}
291 
292 			timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
293 			if (timer == 0)
294 				timer = 1;
295 
296 			/*
297 			 * Start the timers in all of our membership records
298 			 * for the interface on which the query arrived,
299 			 * except those that are already running and those
300 			 * that belong to a "local" group (224.0.0.X).  For
301 			 * timers already running, check if they need to be
302 			 * reset.
303 			 */
304 			in_multi_lock(RW_WRITER);
305 			inm = in_first_multi(&step);
306 			while (inm != NULL) {
307 				if (inm->inm_ifp == ifp &&
308 				    !IN_LOCAL_GROUP(inm->inm_addr.s_addr) &&
309 				    (ip->ip_dst.s_addr == INADDR_ALLHOSTS_GROUP ||
310 				     in_hosteq(ip->ip_dst, inm->inm_addr))) {
311 					switch (inm->inm_state) {
312 					case IGMP_DELAYING_MEMBER:
313 						if (inm->inm_timer <= timer)
314 							break;
315 						/* FALLTHROUGH */
316 					case IGMP_IDLE_MEMBER:
317 					case IGMP_LAZY_MEMBER:
318 					case IGMP_AWAKENING_MEMBER:
319 						inm->inm_state =
320 						    IGMP_DELAYING_MEMBER;
321 						inm->inm_timer =
322 						    IGMP_RANDOM_DELAY(timer);
323 						igmp_timers_on = true;
324 						break;
325 					case IGMP_SLEEPING_MEMBER:
326 						inm->inm_state =
327 						    IGMP_AWAKENING_MEMBER;
328 						break;
329 					}
330 				}
331 				inm = in_next_multi(&step);
332 			}
333 			in_multi_unlock();
334 		}
335 
336 		break;
337 
338 	case IGMP_v1_HOST_MEMBERSHIP_REPORT:
339 		IGMP_STATINC(IGMP_STAT_RCV_REPORTS);
340 
341 		if (ifp->if_flags & IFF_LOOPBACK)
342 			break;
343 
344 		if (!IN_MULTICAST(igmp->igmp_group.s_addr) ||
345 		    !in_hosteq(igmp->igmp_group, ip->ip_dst)) {
346 			IGMP_STATINC(IGMP_STAT_RCV_BADREPORTS);
347 			goto drop;
348 		}
349 
350 		/*
351 		 * KLUDGE: if the IP source address of the report has an
352 		 * unspecified (i.e., zero) subnet number, as is allowed for
353 		 * a booting host, replace it with the correct subnet number
354 		 * so that a process-level multicast routing daemon can
355 		 * determine which subnet it arrived from.  This is necessary
356 		 * to compensate for the lack of any way for a process to
357 		 * determine the arrival interface of an incoming packet.
358 		 */
359 		if ((ip->ip_src.s_addr & IN_CLASSA_NET) == 0) {
360 			int s = pserialize_read_enter();
361 			ia = in_get_ia_from_ifp(ifp); /* XXX */
362 			if (ia)
363 				ip->ip_src.s_addr = ia->ia_subnet;
364 			pserialize_read_exit(s);
365 		}
366 
367 		/*
368 		 * If we belong to the group being reported, stop
369 		 * our timer for that group.
370 		 */
371 		in_multi_lock(RW_WRITER);
372 		inm = in_lookup_multi(igmp->igmp_group, ifp);
373 		if (inm != NULL) {
374 			inm->inm_timer = 0;
375 			IGMP_STATINC(IGMP_STAT_RCV_OURREPORTS);
376 
377 			switch (inm->inm_state) {
378 			case IGMP_IDLE_MEMBER:
379 			case IGMP_LAZY_MEMBER:
380 			case IGMP_AWAKENING_MEMBER:
381 			case IGMP_SLEEPING_MEMBER:
382 				inm->inm_state = IGMP_SLEEPING_MEMBER;
383 				break;
384 			case IGMP_DELAYING_MEMBER:
385 				if (inm->inm_rti->rti_type == IGMP_v1_ROUTER)
386 					inm->inm_state = IGMP_LAZY_MEMBER;
387 				else
388 					inm->inm_state = IGMP_SLEEPING_MEMBER;
389 				break;
390 			}
391 		}
392 		in_multi_unlock();
393 		break;
394 
395 	case IGMP_v2_HOST_MEMBERSHIP_REPORT: {
396 		int s = pserialize_read_enter();
397 #ifdef MROUTING
398 		/*
399 		 * Make sure we don't hear our own membership report.  Fast
400 		 * leave requires knowing that we are the only member of a
401 		 * group.
402 		 */
403 		ia = in_get_ia_from_ifp(ifp);	/* XXX */
404 		if (ia && in_hosteq(ip->ip_src, ia->ia_addr.sin_addr)) {
405 			pserialize_read_exit(s);
406 			break;
407 		}
408 #endif
409 
410 		IGMP_STATINC(IGMP_STAT_RCV_REPORTS);
411 
412 		if (ifp->if_flags & IFF_LOOPBACK) {
413 			pserialize_read_exit(s);
414 			break;
415 		}
416 
417 		if (!IN_MULTICAST(igmp->igmp_group.s_addr) ||
418 		    !in_hosteq(igmp->igmp_group, ip->ip_dst)) {
419 			IGMP_STATINC(IGMP_STAT_RCV_BADREPORTS);
420 			pserialize_read_exit(s);
421 			goto drop;
422 		}
423 
424 		/*
425 		 * KLUDGE: if the IP source address of the report has an
426 		 * unspecified (i.e., zero) subnet number, as is allowed for
427 		 * a booting host, replace it with the correct subnet number
428 		 * so that a process-level multicast routing daemon can
429 		 * determine which subnet it arrived from.  This is necessary
430 		 * to compensate for the lack of any way for a process to
431 		 * determine the arrival interface of an incoming packet.
432 		 */
433 		if ((ip->ip_src.s_addr & IN_CLASSA_NET) == 0) {
434 #ifndef MROUTING
435 			ia = in_get_ia_from_ifp(ifp); /* XXX */
436 #endif
437 			if (ia)
438 				ip->ip_src.s_addr = ia->ia_subnet;
439 		}
440 		pserialize_read_exit(s);
441 
442 		/*
443 		 * If we belong to the group being reported, stop
444 		 * our timer for that group.
445 		 */
446 		in_multi_lock(RW_WRITER);
447 		inm = in_lookup_multi(igmp->igmp_group, ifp);
448 		if (inm != NULL) {
449 			inm->inm_timer = 0;
450 			IGMP_STATINC(IGMP_STAT_RCV_OURREPORTS);
451 
452 			switch (inm->inm_state) {
453 			case IGMP_DELAYING_MEMBER:
454 			case IGMP_IDLE_MEMBER:
455 			case IGMP_AWAKENING_MEMBER:
456 				inm->inm_state = IGMP_LAZY_MEMBER;
457 				break;
458 			case IGMP_LAZY_MEMBER:
459 			case IGMP_SLEEPING_MEMBER:
460 				break;
461 			}
462 		}
463 		in_multi_unlock();
464 		break;
465 	    }
466 	}
467 	m_put_rcvif_psref(ifp, &psref);
468 
469 	/*
470 	 * Pass all valid IGMP packets up to any process(es) listening
471 	 * on a raw IGMP socket.
472 	 */
473 	/*
474 	 * Currently, igmp_input() is always called holding softnet_lock
475 	 * by ipintr()(!NET_MPSAFE) or PR_INPUT_WRAP()(NET_MPSAFE).
476 	 */
477 	KASSERT(mutex_owned(softnet_lock));
478 	rip_input(m, iphlen, proto);
479 	return;
480 
481 drop:
482 	m_put_rcvif_psref(ifp, &psref);
483 	m_freem(m);
484 	return;
485 }
486 
487 int
igmp_joingroup(struct in_multi * inm)488 igmp_joingroup(struct in_multi *inm)
489 {
490 	KASSERT(in_multi_lock_held());
491 	inm->inm_state = IGMP_IDLE_MEMBER;
492 
493 	if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) &&
494 	    (inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0) {
495 		int report_type;
496 
497 		report_type = rti_fill(inm);
498 		if (report_type == 0) {
499 			return ENOMEM;
500 		}
501 		igmp_sendpkt(inm, report_type);
502 		inm->inm_state = IGMP_DELAYING_MEMBER;
503 		inm->inm_timer = IGMP_RANDOM_DELAY(
504 		    IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ);
505 		igmp_timers_on = true;
506 	} else
507 		inm->inm_timer = 0;
508 
509 	return 0;
510 }
511 
512 void
igmp_leavegroup(struct in_multi * inm)513 igmp_leavegroup(struct in_multi *inm)
514 {
515 	KASSERT(in_multi_lock_held());
516 
517 	switch (inm->inm_state) {
518 	case IGMP_DELAYING_MEMBER:
519 	case IGMP_IDLE_MEMBER:
520 		if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) &&
521 		    (inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0)
522 			if (inm->inm_rti->rti_type != IGMP_v1_ROUTER)
523 				igmp_sendpkt(inm, IGMP_HOST_LEAVE_MESSAGE);
524 		break;
525 	case IGMP_LAZY_MEMBER:
526 	case IGMP_AWAKENING_MEMBER:
527 	case IGMP_SLEEPING_MEMBER:
528 		break;
529 	}
530 }
531 
532 void
igmp_fasttimo(void)533 igmp_fasttimo(void)
534 {
535 	struct in_multi *inm;
536 	struct in_multistep step;
537 
538 	/*
539 	 * Quick check to see if any work needs to be done, in order
540 	 * to minimize the overhead of fasttimo processing.
541 	 */
542 	if (!igmp_timers_on) {
543 		return;
544 	}
545 
546 	/* XXX: Needed for ip_output(). */
547 	SOFTNET_LOCK_UNLESS_NET_MPSAFE();
548 
549 	in_multi_lock(RW_WRITER);
550 	igmp_timers_on = false;
551 	inm = in_first_multi(&step);
552 	while (inm != NULL) {
553 		if (inm->inm_timer == 0) {
554 			/* do nothing */
555 		} else if (--inm->inm_timer == 0) {
556 			if (inm->inm_state == IGMP_DELAYING_MEMBER) {
557 				if (inm->inm_rti->rti_type == IGMP_v1_ROUTER)
558 					igmp_sendpkt(inm,
559 					    IGMP_v1_HOST_MEMBERSHIP_REPORT);
560 				else
561 					igmp_sendpkt(inm,
562 					    IGMP_v2_HOST_MEMBERSHIP_REPORT);
563 				inm->inm_state = IGMP_IDLE_MEMBER;
564 			}
565 		} else {
566 			igmp_timers_on = true;
567 		}
568 		inm = in_next_multi(&step);
569 	}
570 	in_multi_unlock();
571 	SOFTNET_UNLOCK_UNLESS_NET_MPSAFE();
572 }
573 
574 void
igmp_slowtimo(void)575 igmp_slowtimo(void)
576 {
577 	router_info_t *rti;
578 
579 	in_multi_lock(RW_WRITER);
580 	LIST_FOREACH(rti, &rti_head, rti_link) {
581 		if (rti->rti_type == IGMP_v1_ROUTER &&
582 		    ++rti->rti_age >= IGMP_AGE_THRESHOLD) {
583 			rti->rti_type = IGMP_v2_ROUTER;
584 		}
585 	}
586 	in_multi_unlock();
587 }
588 
589 /*
590  * igmp_sendpkt: construct an IGMP packet, given the multicast structure
591  * and the type, and send the datagram.
592  */
593 static void
igmp_sendpkt(struct in_multi * inm,int type)594 igmp_sendpkt(struct in_multi *inm, int type)
595 {
596 	struct mbuf *m;
597 	struct igmp *igmp;
598 	struct ip *ip;
599 	struct ip_moptions imo;
600 
601 	KASSERT(in_multi_lock_held());
602 
603 	MGETHDR(m, M_DONTWAIT, MT_HEADER);
604 	if (m == NULL)
605 		return;
606 	KASSERT(max_linkhdr + sizeof(struct ip) + IGMP_MINLEN <= MHLEN);
607 
608 	m->m_data += max_linkhdr;
609 	m->m_len = sizeof(struct ip) + IGMP_MINLEN;
610 	m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
611 
612 	ip = mtod(m, struct ip *);
613 	ip->ip_tos = 0;
614 	ip->ip_len = htons(sizeof(struct ip) + IGMP_MINLEN);
615 	ip->ip_off = htons(0);
616 	ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
617 	ip->ip_p = IPPROTO_IGMP;
618 	ip->ip_src = zeroin_addr;
619 	ip->ip_dst = inm->inm_addr;
620 
621 	m->m_data += sizeof(struct ip);
622 	m->m_len -= sizeof(struct ip);
623 	igmp = mtod(m, struct igmp *);
624 	igmp->igmp_type = type;
625 	igmp->igmp_code = 0;
626 	igmp->igmp_group = inm->inm_addr;
627 	igmp->igmp_cksum = 0;
628 	igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN);
629 	m->m_data -= sizeof(struct ip);
630 	m->m_len += sizeof(struct ip);
631 
632 	imo.imo_multicast_if_index = if_get_index(inm->inm_ifp);
633 	imo.imo_multicast_ttl = 1;
634 
635 	/*
636 	 * Request loopback of the report if we are acting as a multicast
637 	 * router, so that the process-level routing demon can hear it.
638 	 */
639 #ifdef MROUTING
640 	extern struct socket *ip_mrouter;
641 	imo.imo_multicast_loop = (ip_mrouter != NULL);
642 #else
643 	imo.imo_multicast_loop = 0;
644 #endif
645 
646 	/*
647 	 * Note: IP_IGMP_MCAST indicates that in_multilock is held.
648 	 * The caller must still acquire softnet_lock for ip_output().
649 	 */
650 #ifndef NET_MPSAFE
651 	KASSERT(mutex_owned(softnet_lock));
652 #endif
653 	ip_output(m, NULL, NULL, IP_IGMP_MCAST, &imo, NULL);
654 	IGMP_STATINC(IGMP_STAT_SND_REPORTS);
655 }
656 
657 void
igmp_purgeif(ifnet_t * ifp)658 igmp_purgeif(ifnet_t *ifp)
659 {
660 	in_multi_lock(RW_WRITER);
661 	rti_delete(ifp);
662 	in_multi_unlock();
663 }
664 
665 static int
sysctl_net_inet_igmp_stats(SYSCTLFN_ARGS)666 sysctl_net_inet_igmp_stats(SYSCTLFN_ARGS)
667 {
668 	return NETSTAT_SYSCTL(igmpstat_percpu, IGMP_NSTATS);
669 }
670 
671 static void
sysctl_net_inet_igmp_setup(struct sysctllog ** clog)672 sysctl_net_inet_igmp_setup(struct sysctllog **clog)
673 {
674 	sysctl_createv(clog, 0, NULL, NULL,
675 			CTLFLAG_PERMANENT,
676 			CTLTYPE_NODE, "inet", NULL,
677 			NULL, 0, NULL, 0,
678 			CTL_NET, PF_INET, CTL_EOL);
679 	sysctl_createv(clog, 0, NULL, NULL,
680 			CTLFLAG_PERMANENT,
681 			CTLTYPE_NODE, "igmp",
682 			SYSCTL_DESCR("Internet Group Management Protocol"),
683 			NULL, 0, NULL, 0,
684 			CTL_NET, PF_INET, IPPROTO_IGMP, CTL_EOL);
685 	sysctl_createv(clog, 0, NULL, NULL,
686 			CTLFLAG_PERMANENT,
687 			CTLTYPE_STRUCT, "stats",
688 			SYSCTL_DESCR("IGMP statistics"),
689 			sysctl_net_inet_igmp_stats, 0, NULL, 0,
690 			CTL_NET, PF_INET, IPPROTO_IGMP, CTL_CREATE, CTL_EOL);
691 }
692