xref: /dragonfly/sys/netinet6/mld6.c (revision dc71b7ab)
1 /*	$FreeBSD: src/sys/netinet6/mld6.c,v 1.4.2.4 2003/01/23 21:06:47 sam Exp $	*/
2 /*	$DragonFly: src/sys/netinet6/mld6.c,v 1.6 2005/06/03 19:56:08 eirikn Exp $	*/
3 /*	$KAME: mld6.c,v 1.27 2001/04/04 05:17:30 itojun Exp $	*/
4 
5 /*
6  * Copyright (C) 1998 WIDE Project.
7  * All rights reserved.
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. Neither the name of the project 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.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT 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 PROJECT 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
31  * SUCH DAMAGE.
32  */
33 
34 /*
35  * Copyright (c) 1988 Stephen Deering.
36  * Copyright (c) 1992, 1993
37  *	The Regents of the University of California.  All rights reserved.
38  *
39  * This code is derived from software contributed to Berkeley by
40  * Stephen Deering of Stanford University.
41  *
42  * Redistribution and use in source and binary forms, with or without
43  * modification, are permitted provided that the following conditions
44  * are met:
45  * 1. Redistributions of source code must retain the above copyright
46  *    notice, this list of conditions and the following disclaimer.
47  * 2. Redistributions in binary form must reproduce the above copyright
48  *    notice, this list of conditions and the following disclaimer in the
49  *    documentation and/or other materials provided with the distribution.
50  * 3. Neither the name of the University nor the names of its contributors
51  *    may be used to endorse or promote products derived from this software
52  *    without specific prior written permission.
53  *
54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64  * SUCH DAMAGE.
65  *
66  *	@(#)igmp.c	8.1 (Berkeley) 7/19/93
67  */
68 
69 #include "opt_inet.h"
70 #include "opt_inet6.h"
71 
72 #include <sys/param.h>
73 #include <sys/systm.h>
74 #include <sys/mbuf.h>
75 #include <sys/socket.h>
76 #include <sys/protosw.h>
77 #include <sys/syslog.h>
78 #include <sys/thread2.h>
79 
80 #include <net/if.h>
81 
82 #include <netinet/in.h>
83 #include <netinet/in_var.h>
84 #include <netinet/ip6.h>
85 #include <netinet6/ip6_var.h>
86 #include <netinet/icmp6.h>
87 #include <netinet6/mld6_var.h>
88 
89 #include <net/net_osdep.h>
90 
91 /*
92  * Protocol constants
93  */
94 
95 /* denotes that the MLD max response delay field specifies time in milliseconds */
96 #define MLD6_TIMER_SCALE	1000
97 /*
98  * time between repetitions of a node's initial report of interest in a
99  * multicast address(in seconds)
100  */
101 #define MLD6_UNSOLICITED_REPORT_INTERVAL	10
102 
103 static struct ip6_pktopts ip6_opts;
104 static int mld6_timers_are_running;
105 /* XXX: These are necessary for KAME's link-local hack */
106 static struct in6_addr mld6_all_nodes_linklocal = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
107 static struct in6_addr mld6_all_routers_linklocal = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
108 
109 static void mld6_sendpkt (struct in6_multi *, int, const struct in6_addr *);
110 
111 static struct lwkt_token mld6_token = LWKT_TOKEN_INITIALIZER(mp_token);
112 
113 
114 void
115 mld6_init(void)
116 {
117 	static u_int8_t hbh_buf[8];
118 	struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
119 	u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
120 
121 	mld6_timers_are_running = 0;
122 
123 	/* ip6h_nxt will be fill in later */
124 	hbh->ip6h_len = 0;	/* (8 >> 3) - 1 */
125 
126 	/* XXX: grotty hard coding... */
127 	hbh_buf[2] = IP6OPT_PADN;	/* 2 byte padding */
128 	hbh_buf[3] = 0;
129 	hbh_buf[4] = IP6OPT_RTALERT;
130 	hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
131 	bcopy((caddr_t)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));
132 
133 	init_ip6pktopts(&ip6_opts);
134 	ip6_opts.ip6po_hbh = hbh;
135 }
136 
137 void
138 mld6_start_listening(struct in6_multi *in6m)
139 {
140 	/*
141 	 * RFC2710 page 10:
142 	 * The node never sends a Report or Done for the link-scope all-nodes
143 	 * address.
144 	 * MLD messages are never sent for multicast addresses whose scope is 0
145 	 * (reserved) or 1 (node-local).
146 	 */
147 	lwkt_gettoken(&mld6_token);
148 	mld6_all_nodes_linklocal.s6_addr16[1] =
149 		htons(in6m->in6m_ifp->if_index); /* XXX */
150 	if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal) ||
151 	    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) < IPV6_ADDR_SCOPE_LINKLOCAL) {
152 		in6m->in6m_timer = 0;
153 		in6m->in6m_state = MLD6_OTHERLISTENER;
154 	} else {
155 		mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
156 		in6m->in6m_timer = MLD6_RANDOM_DELAY(
157 			MLD6_UNSOLICITED_REPORT_INTERVAL * PR_FASTHZ);
158 		in6m->in6m_state = MLD6_IREPORTEDLAST;
159 		mld6_timers_are_running = 1;
160 	}
161 	lwkt_reltoken(&mld6_token);
162 }
163 
164 void
165 mld6_stop_listening(struct in6_multi *in6m)
166 {
167 	mld6_all_nodes_linklocal.s6_addr16[1] =
168 		htons(in6m->in6m_ifp->if_index); /* XXX */
169 	mld6_all_routers_linklocal.s6_addr16[1] =
170 		htons(in6m->in6m_ifp->if_index); /* XXX: necessary when mrouting */
171 
172 	if (in6m->in6m_state == MLD6_IREPORTEDLAST &&
173 	    (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal)) &&
174 	    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) > IPV6_ADDR_SCOPE_NODELOCAL)
175 		mld6_sendpkt(in6m, MLD_LISTENER_DONE,
176 			     &mld6_all_routers_linklocal);
177 }
178 
179 void
180 mld6_input(struct mbuf *m, int off)
181 {
182 	struct ip6_hdr *ip6;
183 	struct mld_hdr *mldh;
184 	struct ifnet *ifp = m->m_pkthdr.rcvif;
185 	struct in6_multi *in6m;
186 	struct in6_ifaddr *ia;
187 	struct ifmultiaddr *ifma;
188 	int timer;		/* timer value in the MLD query header */
189 
190 #ifndef PULLDOWN_TEST
191 	IP6_EXTHDR_CHECK(m, off, sizeof(*mldh),);
192 	mldh = (struct mld_hdr *)(mtod(m, caddr_t) + off);
193 #else
194 	IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
195 	if (mldh == NULL) {
196 		icmp6stat.icp6s_tooshort++;
197 		return;
198 	}
199 #endif
200 
201 	lwkt_gettoken(&mld6_token);
202 	/* source address validation */
203 	ip6 = mtod(m, struct ip6_hdr *);/* in case mpullup */
204 	if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
205 		log(LOG_ERR,
206 		    "mld6_input: src %s is not link-local (grp=%s)\n",
207 		    ip6_sprintf(&ip6->ip6_src),
208 		    ip6_sprintf(&mldh->mld_addr));
209 		/*
210 		 * spec (RFC2710) does not explicitly
211 		 * specify to discard the packet from a non link-local
212 		 * source address. But we believe it's expected to do so.
213 		 * XXX: do we have to allow :: as source?
214 		 */
215 		m_freem(m);
216 		lwkt_reltoken(&mld6_token);
217 		return;
218 	}
219 
220 	/*
221 	 * In the MLD6 specification, there are 3 states and a flag.
222 	 *
223 	 * In Non-Listener state, we simply don't have a membership record.
224 	 * In Delaying Listener state, our timer is running (in6m->in6m_timer)
225 	 * In Idle Listener state, our timer is not running (in6m->in6m_timer==0)
226 	 *
227 	 * The flag is in6m->in6m_state, it is set to MLD6_OTHERLISTENER if
228 	 * we have heard a report from another member, or MLD6_IREPORTEDLAST
229 	 * if we sent the last report.
230 	 */
231 	switch(mldh->mld_type) {
232 	case MLD_LISTENER_QUERY:
233 		if (ifp->if_flags & IFF_LOOPBACK)
234 			break;
235 
236 		if (!IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) &&
237 		    !IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
238 			break;	/* print error or log stat? */
239 		if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
240 			mldh->mld_addr.s6_addr16[1] =
241 				htons(ifp->if_index); /* XXX */
242 
243 		/*
244 		 * - Start the timers in all of our membership records
245 		 *   that the query applies to for the interface on
246 		 *   which the query arrived excl. those that belong
247 		 *   to the "all-nodes" group (ff02::1).
248 		 * - Restart any timer that is already running but has
249 		 *   A value longer than the requested timeout.
250 		 * - Use the value specified in the query message as
251 		 *   the maximum timeout.
252 		 */
253 		IFP_TO_IA6(ifp, ia);
254 		if (ia == NULL)
255 			break;
256 
257 		/*
258 		 * XXX: System timer resolution is too low to handle Max
259 		 * Response Delay, so set 1 to the internal timer even if
260 		 * the calculated value equals to zero when Max Response
261 		 * Delay is positive.
262 		 */
263 		timer = ntohs(mldh->mld_maxdelay)*PR_FASTHZ/MLD6_TIMER_SCALE;
264 		if (timer == 0 && mldh->mld_maxdelay)
265 			timer = 1;
266 		mld6_all_nodes_linklocal.s6_addr16[1] =
267 			htons(ifp->if_index); /* XXX */
268 
269 		TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
270 		{
271 			if (ifma->ifma_addr->sa_family != AF_INET6)
272 				continue;
273 			in6m = (struct in6_multi *)ifma->ifma_protospec;
274 			if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr,
275 					&mld6_all_nodes_linklocal) ||
276 			    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
277 			    IPV6_ADDR_SCOPE_LINKLOCAL)
278 				continue;
279 
280 			if (IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) ||
281 			    IN6_ARE_ADDR_EQUAL(&mldh->mld_addr,
282 						&in6m->in6m_addr))
283 			{
284 				if (timer == 0) {
285 					/* send a report immediately */
286 					mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
287 						NULL);
288 					in6m->in6m_timer = 0; /* reset timer */
289 					in6m->in6m_state = MLD6_IREPORTEDLAST;
290 				}
291 				else if (in6m->in6m_timer == 0 || /*idle state*/
292 					in6m->in6m_timer > timer) {
293 					in6m->in6m_timer =
294 						MLD6_RANDOM_DELAY(timer);
295 					mld6_timers_are_running = 1;
296 				}
297 			}
298 		}
299 
300 		if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
301 			mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
302 		break;
303 	case MLD_LISTENER_REPORT:
304 		/*
305 		 * For fast leave to work, we have to know that we are the
306 		 * last person to send a report for this group.  Reports
307 		 * can potentially get looped back if we are a multicast
308 		 * router, so discard reports sourced by me.
309 		 * Note that it is impossible to check IFF_LOOPBACK flag of
310 		 * ifp for this purpose, since ip6_mloopback pass the physical
311 		 * interface to looutput.
312 		 */
313 		if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
314 			break;
315 
316 		if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
317 			break;
318 
319 		if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
320 			mldh->mld_addr.s6_addr16[1] =
321 				htons(ifp->if_index); /* XXX */
322 		/*
323 		 * If we belong to the group being reported, stop
324 		 * our timer for that group.
325 		 */
326 		IN6_LOOKUP_MULTI(mldh->mld_addr, ifp, in6m);
327 		if (in6m) {
328 			in6m->in6m_timer = 0; /* transit to idle state */
329 			in6m->in6m_state = MLD6_OTHERLISTENER; /* clear flag */
330 		}
331 
332 		if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
333 			mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
334 		break;
335 	default:		/* this is impossible */
336 		log(LOG_ERR, "mld6_input: illegal type(%d)", mldh->mld_type);
337 		break;
338 	}
339 
340 	m_freem(m);
341 	lwkt_reltoken(&mld6_token);
342 }
343 
344 void
345 mld6_fasttimeo(void)
346 {
347 	struct in6_multi *in6m;
348 	struct in6_multistep step;
349 
350 	/*
351 	 * Quick check to see if any work needs to be done, in order
352 	 * to minimize the overhead of fasttimo processing.
353 	 */
354 	lwkt_gettoken(&mld6_token);
355 	if (!mld6_timers_are_running) {
356 		lwkt_reltoken(&mld6_token);
357 		return;
358 	}
359 
360 	mld6_timers_are_running = 0;
361 	IN6_FIRST_MULTI(step, in6m);
362 	while (in6m != NULL) {
363 		if (in6m->in6m_timer == 0) {
364 			/* do nothing */
365 		} else if (--in6m->in6m_timer == 0) {
366 			mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
367 			in6m->in6m_state = MLD6_IREPORTEDLAST;
368 		} else {
369 			mld6_timers_are_running = 1;
370 		}
371 		IN6_NEXT_MULTI(step, in6m);
372 	}
373 	lwkt_reltoken(&mld6_token);
374 }
375 
376 static void
377 mld6_sendpkt(struct in6_multi *in6m, int type, const struct in6_addr *dst)
378 {
379 	struct mbuf *mh, *md;
380 	struct mld_hdr *mldh;
381 	struct ip6_hdr *ip6;
382 	struct ip6_moptions im6o;
383 	struct in6_ifaddr *ia;
384 	struct ifnet *ifp = in6m->in6m_ifp;
385 	struct ifnet *outif = NULL;
386 
387 	/*
388 	 * At first, find a link local address on the outgoing interface
389 	 * to use as the source address of the MLD packet.
390 	 */
391 	if ((ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST))
392 	    == NULL)
393 		return;
394 
395 	/*
396 	 * Allocate mbufs to store ip6 header and MLD header.
397 	 * We allocate 2 mbufs and make chain in advance because
398 	 * it is more convenient when inserting the hop-by-hop option later.
399 	 */
400 	MGETHDR(mh, MB_DONTWAIT, MT_HEADER);
401 	if (mh == NULL)
402 		return;
403 	MGET(md, MB_DONTWAIT, MT_DATA);
404 	if (md == NULL) {
405 		m_free(mh);
406 		return;
407 	}
408 	mh->m_next = md;
409 
410 	mh->m_pkthdr.rcvif = NULL;
411 	mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
412 	mh->m_len = sizeof(struct ip6_hdr);
413 	MH_ALIGN(mh, sizeof(struct ip6_hdr));
414 
415 	/* fill in the ip6 header */
416 	ip6 = mtod(mh, struct ip6_hdr *);
417 	ip6->ip6_flow = 0;
418 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
419 	ip6->ip6_vfc |= IPV6_VERSION;
420 	/* ip6_plen will be set later */
421 	ip6->ip6_nxt = IPPROTO_ICMPV6;
422 	/* ip6_hlim will be set by im6o.im6o_multicast_hlim */
423 	ip6->ip6_src = ia->ia_addr.sin6_addr;
424 	ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
425 
426 	/* fill in the MLD header */
427 	md->m_len = sizeof(struct mld_hdr);
428 	mldh = mtod(md, struct mld_hdr *);
429 	mldh->mld_type = type;
430 	mldh->mld_code = 0;
431 	mldh->mld_cksum = 0;
432 	/* XXX: we assume the function will not be called for query messages */
433 	mldh->mld_maxdelay = 0;
434 	mldh->mld_reserved = 0;
435 	mldh->mld_addr = in6m->in6m_addr;
436 	if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
437 		mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
438 	mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6,
439 				     sizeof(struct ip6_hdr),
440 				     sizeof(struct mld_hdr));
441 
442 	/* construct multicast option */
443 	bzero(&im6o, sizeof(im6o));
444 	im6o.im6o_multicast_ifp = ifp;
445 	im6o.im6o_multicast_hlim = 1;
446 
447 	/*
448 	 * Request loopback of the report if we are acting as a multicast
449 	 * router, so that the process-level routing daemon can hear it.
450 	 */
451 	im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
452 
453 	/* increment output statictics */
454 	icmp6stat.icp6s_outhist[type]++;
455 
456 	ip6_output(mh, &ip6_opts, NULL, 0, &im6o, &outif, NULL);
457 	if (outif) {
458 		icmp6_ifstat_inc(outif, ifs6_out_msg);
459 		switch (type) {
460 		case MLD_LISTENER_QUERY:
461 			icmp6_ifstat_inc(outif, ifs6_out_mldquery);
462 			break;
463 		case MLD_LISTENER_REPORT:
464 			icmp6_ifstat_inc(outif, ifs6_out_mldreport);
465 			break;
466 		case MLD_LISTENER_DONE:
467 			icmp6_ifstat_inc(outif, ifs6_out_mlddone);
468 			break;
469 		}
470 	}
471 }
472