1 /* $OpenBSD: mld6.c,v 1.64 2024/08/19 08:07:16 jsg Exp $ */
2 /* $KAME: mld6.c,v 1.26 2001/02/16 14:50:35 itojun Exp $ */
3
4 /*
5 * Copyright (C) 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /*
34 * Copyright (c) 1988 Stephen Deering.
35 * Copyright (c) 1992, 1993
36 * The Regents of the University of California. All rights reserved.
37 *
38 * This code is derived from software contributed to Berkeley by
39 * Stephen Deering of Stanford University.
40 *
41 * Redistribution and use in source and binary forms, with or without
42 * modification, are permitted provided that the following conditions
43 * are met:
44 * 1. Redistributions of source code must retain the above copyright
45 * notice, this list of conditions and the following disclaimer.
46 * 2. Redistributions in binary form must reproduce the above copyright
47 * notice, this list of conditions and the following disclaimer in the
48 * documentation and/or other materials provided with the distribution.
49 * 3. Neither the name of the University nor the names of its contributors
50 * may be used to endorse or promote products derived from this software
51 * without specific prior written permission.
52 *
53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63 * SUCH DAMAGE.
64 *
65 * @(#)igmp.c 8.1 (Berkeley) 7/19/93
66 */
67
68 #include <sys/param.h>
69 #include <sys/systm.h>
70 #include <sys/mbuf.h>
71 #include <sys/socket.h>
72 #include <sys/protosw.h>
73 #include <sys/syslog.h>
74
75 #include <net/if.h>
76 #include <net/if_var.h>
77 #include <net/route.h>
78
79 #include <netinet/in.h>
80 #include <netinet6/in6_var.h>
81 #include <netinet/ip6.h>
82 #include <netinet6/ip6_var.h>
83 #include <netinet/icmp6.h>
84 #include <netinet6/mld6.h>
85 #include <netinet6/mld6_var.h>
86
87 static struct ip6_pktopts ip6_opts;
88 int mld6_timers_are_running; /* [a] shortcut for fast timer */
89
90 int mld6_checktimer(struct ifnet *);
91 static void mld6_sendpkt(struct in6_multi *, int, const struct in6_addr *);
92
93 void
mld6_init(void)94 mld6_init(void)
95 {
96 static u_int8_t hbh_buf[8];
97 struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
98 u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
99
100 mld6_timers_are_running = 0;
101
102 /* ip6h_nxt will be fill in later */
103 hbh->ip6h_len = 0; /* (8 >> 3) - 1 */
104
105 /* XXX: grotty hard coding... */
106 hbh_buf[2] = IP6OPT_PADN; /* 2 byte padding */
107 hbh_buf[3] = 0;
108 hbh_buf[4] = IP6OPT_ROUTER_ALERT;
109 hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
110 memcpy(&hbh_buf[6], (caddr_t)&rtalert_code, sizeof(u_int16_t));
111
112 ip6_initpktopts(&ip6_opts);
113 ip6_opts.ip6po_hbh = hbh;
114 }
115
116 void
mld6_start_listening(struct in6_multi * in6m)117 mld6_start_listening(struct in6_multi *in6m)
118 {
119 /* XXX: These are necessary for KAME's link-local hack */
120 struct in6_addr all_nodes = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
121 int running = 0;
122
123 /*
124 * RFC2710 page 10:
125 * The node never sends a Report or Done for the link-scope all-nodes
126 * address.
127 * MLD messages are never sent for multicast addresses whose scope is 0
128 * (reserved) or 1 (node-local).
129 */
130 all_nodes.s6_addr16[1] = htons(in6m->in6m_ifidx);
131 if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_nodes) ||
132 __IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
133 __IPV6_ADDR_SCOPE_LINKLOCAL) {
134 in6m->in6m_timer = 0;
135 in6m->in6m_state = MLD_OTHERLISTENER;
136 } else {
137 mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
138 in6m->in6m_timer =
139 MLD_RANDOM_DELAY(MLD_V1_MAX_RI *
140 PR_FASTHZ);
141 in6m->in6m_state = MLD_IREPORTEDLAST;
142 running = 1;
143 }
144
145 if (running) {
146 membar_producer();
147 atomic_store_int(&mld6_timers_are_running, running);
148 }
149 }
150
151 void
mld6_stop_listening(struct in6_multi * in6m)152 mld6_stop_listening(struct in6_multi *in6m)
153 {
154 /* XXX: These are necessary for KAME's link-local hack */
155 struct in6_addr all_nodes = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
156 struct in6_addr all_routers = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
157
158 all_nodes.s6_addr16[1] = htons(in6m->in6m_ifidx);
159 /* XXX: necessary when mrouting */
160 all_routers.s6_addr16[1] = htons(in6m->in6m_ifidx);
161
162 if (in6m->in6m_state == MLD_IREPORTEDLAST &&
163 (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_nodes)) &&
164 __IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) >
165 __IPV6_ADDR_SCOPE_INTFACELOCAL)
166 mld6_sendpkt(in6m, MLD_LISTENER_DONE, &all_routers);
167 }
168
169 void
mld6_input(struct mbuf * m,int off)170 mld6_input(struct mbuf *m, int off)
171 {
172 struct ip6_hdr *ip6;
173 struct mld_hdr *mldh;
174 struct ifnet *ifp;
175 struct in6_multi *in6m;
176 struct ifmaddr *ifma;
177 int timer; /* timer value in the MLD query header */
178 int running = 0;
179 /* XXX: These are necessary for KAME's link-local hack */
180 struct in6_addr all_nodes = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
181
182 IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
183 if (mldh == NULL) {
184 icmp6stat_inc(icp6s_tooshort);
185 return;
186 }
187
188 /* source address validation */
189 ip6 = mtod(m, struct ip6_hdr *);/* in case mpullup */
190 if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
191 #if 0
192 char src[INET6_ADDRSTRLEN], grp[INET6_ADDRSTRLEN];
193
194 log(LOG_ERR,
195 "mld_input: src %s is not link-local (grp=%s)\n",
196 inet_ntop(AF_INET6, &ip6->ip6_src, src, sizeof(src)),
197 inet_ntop(AF_INET6, &mldh->mld_addr, grp, sizeof(grp)));
198 #endif
199 /*
200 * spec (RFC2710) does not explicitly
201 * specify to discard the packet from a non link-local
202 * source address. But we believe it's expected to do so.
203 */
204 m_freem(m);
205 return;
206 }
207
208 ifp = if_get(m->m_pkthdr.ph_ifidx);
209 if (ifp == NULL) {
210 m_freem(m);
211 return;
212 }
213
214 /*
215 * In the MLD6 specification, there are 3 states and a flag.
216 *
217 * In Non-Listener state, we simply don't have a membership record.
218 * In Delaying Listener state, our timer is running (in6m->in6m_timer)
219 * In Idle Listener state, our timer is not running (in6m->in6m_timer==0)
220 *
221 * The flag is in6m->in6m_state, it is set to MLD_OTHERLISTENER if
222 * we have heard a report from another member, or MLD_IREPORTEDLAST
223 * if we sent the last report.
224 */
225 switch(mldh->mld_type) {
226 case MLD_LISTENER_QUERY:
227 if (ifp->if_flags & IFF_LOOPBACK)
228 break;
229
230 if (!IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) &&
231 !IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
232 break; /* print error or log stat? */
233 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
234 mldh->mld_addr.s6_addr16[1] =
235 htons(ifp->if_index); /* XXX */
236
237 /*
238 * - Start the timers in all of our membership records
239 * that the query applies to for the interface on
240 * which the query arrived excl. those that belong
241 * to the "all-nodes" group (ff02::1).
242 * - Restart any timer that is already running but has
243 * A value longer than the requested timeout.
244 * - Use the value specified in the query message as
245 * the maximum timeout.
246 */
247
248 /*
249 * XXX: System timer resolution is too low to handle Max
250 * Response Delay, so set 1 to the internal timer even if
251 * the calculated value equals to zero when Max Response
252 * Delay is positive.
253 */
254 timer = ntohs(mldh->mld_maxdelay)*PR_FASTHZ/MLD_TIMER_SCALE;
255 if (timer == 0 && mldh->mld_maxdelay)
256 timer = 1;
257 all_nodes.s6_addr16[1] = htons(ifp->if_index);
258
259 TAILQ_FOREACH(ifma, &ifp->if_maddrlist, ifma_list) {
260 if (ifma->ifma_addr->sa_family != AF_INET6)
261 continue;
262 in6m = ifmatoin6m(ifma);
263 if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &all_nodes) ||
264 __IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
265 __IPV6_ADDR_SCOPE_LINKLOCAL)
266 continue;
267
268 if (IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) ||
269 IN6_ARE_ADDR_EQUAL(&mldh->mld_addr,
270 &in6m->in6m_addr))
271 {
272 if (timer == 0) {
273 /* send a report immediately */
274 mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
275 NULL);
276 in6m->in6m_timer = 0; /* reset timer */
277 in6m->in6m_state = MLD_IREPORTEDLAST;
278 } else if (in6m->in6m_timer == 0 || /* idle */
279 in6m->in6m_timer > timer) {
280 in6m->in6m_timer =
281 MLD_RANDOM_DELAY(timer);
282 running = 1;
283 }
284 }
285 }
286
287 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
288 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
289 break;
290 case MLD_LISTENER_REPORT:
291 /*
292 * For fast leave to work, we have to know that we are the
293 * last person to send a report for this group. Reports
294 * can potentially get looped back if we are a multicast
295 * router, so discard reports sourced by me.
296 * Note that it is impossible to check IFF_LOOPBACK flag of
297 * ifp for this purpose, since ip6_mloopback pass the physical
298 * interface to if_input_local().
299 */
300 if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
301 break;
302
303 if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
304 break;
305
306 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
307 mldh->mld_addr.s6_addr16[1] =
308 htons(ifp->if_index); /* XXX */
309 /*
310 * If we belong to the group being reported, stop
311 * our timer for that group.
312 */
313 IN6_LOOKUP_MULTI(mldh->mld_addr, ifp, in6m);
314 if (in6m) {
315 in6m->in6m_timer = 0; /* transit to idle state */
316 in6m->in6m_state = MLD_OTHERLISTENER; /* clear flag */
317 }
318
319 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
320 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
321 break;
322 default: /* this is impossible */
323 #if 0
324 /*
325 * this case should be impossible because of filtering in
326 * icmp6_input(). But we explicitly disabled this part
327 * just in case.
328 */
329 log(LOG_ERR, "mld_input: illegal type(%d)", mldh->mld_type);
330 #endif
331 break;
332 }
333
334 if (running) {
335 membar_producer();
336 atomic_store_int(&mld6_timers_are_running, running);
337 }
338
339 if_put(ifp);
340 m_freem(m);
341 }
342
343 void
mld6_fasttimeo(void)344 mld6_fasttimeo(void)
345 {
346 struct ifnet *ifp;
347 int running = 0;
348
349 /*
350 * Quick check to see if any work needs to be done, in order
351 * to minimize the overhead of fasttimo processing.
352 * Variable mld6_timers_are_running is read atomically, but without
353 * lock intentionally. In case it is not set due to MP races, we may
354 * miss to check the timers. Then run the loop at next fast timeout.
355 */
356 if (!atomic_load_int(&mld6_timers_are_running))
357 return;
358 membar_consumer();
359
360 NET_LOCK();
361
362 TAILQ_FOREACH(ifp, &ifnetlist, if_list) {
363 if (mld6_checktimer(ifp))
364 running = 1;
365 }
366
367 membar_producer();
368 atomic_store_int(&mld6_timers_are_running, running);
369
370 NET_UNLOCK();
371 }
372
373 int
mld6_checktimer(struct ifnet * ifp)374 mld6_checktimer(struct ifnet *ifp)
375 {
376 struct in6_multi *in6m;
377 struct ifmaddr *ifma;
378 int running = 0;
379
380 NET_ASSERT_LOCKED();
381
382 TAILQ_FOREACH(ifma, &ifp->if_maddrlist, ifma_list) {
383 if (ifma->ifma_addr->sa_family != AF_INET6)
384 continue;
385 in6m = ifmatoin6m(ifma);
386 if (in6m->in6m_timer == 0) {
387 /* do nothing */
388 } else if (--in6m->in6m_timer == 0) {
389 mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
390 in6m->in6m_state = MLD_IREPORTEDLAST;
391 } else {
392 running = 1;
393 }
394 }
395
396 return (running);
397 }
398
399 static void
mld6_sendpkt(struct in6_multi * in6m,int type,const struct in6_addr * dst)400 mld6_sendpkt(struct in6_multi *in6m, int type, const struct in6_addr *dst)
401 {
402 struct mbuf *mh, *md;
403 struct mld_hdr *mldh;
404 struct ip6_hdr *ip6;
405 struct ip6_moptions im6o;
406 struct in6_ifaddr *ia6;
407 struct ifnet *ifp;
408 int ignflags;
409
410 ifp = if_get(in6m->in6m_ifidx);
411 if (ifp == NULL)
412 return;
413
414 /*
415 * At first, find a link local address on the outgoing interface
416 * to use as the source address of the MLD packet.
417 * We do not reject tentative addresses for MLD report to deal with
418 * the case where we first join a link-local address.
419 */
420 ignflags = IN6_IFF_DUPLICATED|IN6_IFF_ANYCAST;
421 if ((ia6 = in6ifa_ifpforlinklocal(ifp, ignflags)) == NULL) {
422 if_put(ifp);
423 return;
424 }
425 if ((ia6->ia6_flags & IN6_IFF_TENTATIVE))
426 ia6 = NULL;
427
428 /*
429 * Allocate mbufs to store ip6 header and MLD header.
430 * We allocate 2 mbufs and make chain in advance because
431 * it is more convenient when inserting the hop-by-hop option later.
432 */
433 MGETHDR(mh, M_DONTWAIT, MT_HEADER);
434 if (mh == NULL) {
435 if_put(ifp);
436 return;
437 }
438 MGET(md, M_DONTWAIT, MT_DATA);
439 if (md == NULL) {
440 m_free(mh);
441 if_put(ifp);
442 return;
443 }
444 mh->m_next = md;
445
446 mh->m_pkthdr.ph_ifidx = 0;
447 mh->m_pkthdr.ph_rtableid = ifp->if_rdomain;
448 mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
449 mh->m_len = sizeof(struct ip6_hdr);
450 m_align(mh, sizeof(struct ip6_hdr));
451
452 /* fill in the ip6 header */
453 ip6 = mtod(mh, struct ip6_hdr *);
454 ip6->ip6_flow = 0;
455 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
456 ip6->ip6_vfc |= IPV6_VERSION;
457 /* ip6_plen will be set later */
458 ip6->ip6_nxt = IPPROTO_ICMPV6;
459 /* ip6_hlim will be set by im6o.im6o_hlim */
460 ip6->ip6_src = ia6 ? ia6->ia_addr.sin6_addr : in6addr_any;
461 ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
462
463 /* fill in the MLD header */
464 md->m_len = sizeof(struct mld_hdr);
465 mldh = mtod(md, struct mld_hdr *);
466 mldh->mld_type = type;
467 mldh->mld_code = 0;
468 mldh->mld_cksum = 0;
469 /* XXX: we assume the function will not be called for query messages */
470 mldh->mld_maxdelay = 0;
471 mldh->mld_reserved = 0;
472 mldh->mld_addr = in6m->in6m_addr;
473 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
474 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
475 mh->m_pkthdr.csum_flags |= M_ICMP_CSUM_OUT;
476
477 /* construct multicast option */
478 bzero(&im6o, sizeof(im6o));
479 im6o.im6o_ifidx = ifp->if_index;
480 im6o.im6o_hlim = 1;
481
482 /*
483 * Request loopback of the report if we are acting as a multicast
484 * router, so that the process-level routing daemon can hear it.
485 */
486 #ifdef MROUTING
487 im6o.im6o_loop = (ip6_mrouter[ifp->if_rdomain] != NULL);
488 #endif
489 if_put(ifp);
490
491 icmp6stat_inc(icp6s_outhist + type);
492 ip6_output(mh, &ip6_opts, NULL, ia6 ? 0 : IPV6_UNSPECSRC, &im6o,
493 NULL);
494 }
495