1 /* $OpenBSD: mld6.c,v 1.24 2007/06/01 00:52:38 henning 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 #include <dev/rndvar.h>
75
76 #include <net/if.h>
77
78 #include <netinet/in.h>
79 #include <netinet/in_var.h>
80 #include <netinet/ip6.h>
81 #include <netinet6/ip6_var.h>
82 #include <netinet/icmp6.h>
83 #include <netinet6/mld6_var.h>
84
85 /*
86 * Protocol constants
87 */
88
89 /* denotes that the MLD max response delay field specifies time in milliseconds */
90 #define MLD_TIMER_SCALE 1000
91 /*
92 * time between repetitions of a node's initial report of interest in a
93 * multicast address(in seconds)
94 */
95 #define MLD_UNSOLICITED_REPORT_INTERVAL 10
96
97 static struct ip6_pktopts ip6_opts;
98 static int mld_timers_are_running;
99 /* XXX: These are necessary for KAME's link-local hack */
100 static struct in6_addr mld_all_nodes_linklocal = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
101 static struct in6_addr mld_all_routers_linklocal = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
102
103 static void mld6_sendpkt(struct in6_multi *, int, const struct in6_addr *);
104
105 void
106 mld6_init()
107 {
108 static u_int8_t hbh_buf[8];
109 struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
110 u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
111
112 mld_timers_are_running = 0;
113
114 /* ip6h_nxt will be fill in later */
115 hbh->ip6h_len = 0; /* (8 >> 3) - 1 */
116
117 /* XXX: grotty hard coding... */
118 hbh_buf[2] = IP6OPT_PADN; /* 2 byte padding */
119 hbh_buf[3] = 0;
120 hbh_buf[4] = IP6OPT_ROUTER_ALERT;
121 hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
122 bcopy((caddr_t)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));
123
124 ip6_opts.ip6po_hbh = hbh;
125 }
126
127 void
128 mld6_start_listening(in6m)
129 struct in6_multi *in6m;
130 {
131 int s = splsoftnet();
132
133 /*
134 * RFC2710 page 10:
135 * The node never sends a Report or Done for the link-scope all-nodes
136 * address.
137 * MLD messages are never sent for multicast addresses whose scope is 0
138 * (reserved) or 1 (node-local).
139 */
140 mld_all_nodes_linklocal.s6_addr16[1] =
141 htons(in6m->in6m_ifp->if_index); /* XXX */
142 if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld_all_nodes_linklocal) ||
143 IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) < IPV6_ADDR_SCOPE_LINKLOCAL) {
144 in6m->in6m_timer = 0;
145 in6m->in6m_state = MLD_OTHERLISTENER;
146 } else {
147 mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
148 in6m->in6m_timer =
149 MLD_RANDOM_DELAY(MLD_UNSOLICITED_REPORT_INTERVAL *
150 PR_FASTHZ);
151 in6m->in6m_state = MLD_IREPORTEDLAST;
152 mld_timers_are_running = 1;
153 }
154 splx(s);
155 }
156
157 void
158 mld6_stop_listening(in6m)
159 struct in6_multi *in6m;
160 {
161 mld_all_nodes_linklocal.s6_addr16[1] =
162 htons(in6m->in6m_ifp->if_index); /* XXX */
163 mld_all_routers_linklocal.s6_addr16[1] =
164 htons(in6m->in6m_ifp->if_index); /* XXX: necessary when mrouting */
165
166 if (in6m->in6m_state == MLD_IREPORTEDLAST &&
167 (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld_all_nodes_linklocal)) &&
168 IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) > IPV6_ADDR_SCOPE_INTFACELOCAL)
169 mld6_sendpkt(in6m, MLD_LISTENER_DONE,
170 &mld_all_routers_linklocal);
171 }
172
173 void
174 mld6_input(m, off)
175 struct mbuf *m;
176 int off;
177 {
178 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
179 struct mld_hdr *mldh;
180 struct ifnet *ifp = m->m_pkthdr.rcvif;
181 struct in6_multi *in6m;
182 struct in6_ifaddr *ia;
183 int timer; /* timer value in the MLD query header */
184
185 IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
186 if (mldh == NULL) {
187 icmp6stat.icp6s_tooshort++;
188 return;
189 }
190
191 /* source address validation */
192 ip6 = mtod(m, struct ip6_hdr *);/* in case mpullup */
193 if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
194 #if 0
195 log(LOG_ERR,
196 "mld_input: src %s is not link-local (grp=%s)\n",
197 ip6_sprintf(&ip6->ip6_src),
198 ip6_sprintf(&mldh->mld_addr));
199 #endif
200 /*
201 * spec (RFC2710) does not explicitly
202 * specify to discard the packet from a non link-local
203 * source address. But we believe it's expected to do so.
204 */
205 m_freem(m);
206 return;
207 }
208
209 /*
210 * In the MLD6 specification, there are 3 states and a flag.
211 *
212 * In Non-Listener state, we simply don't have a membership record.
213 * In Delaying Listener state, our timer is running (in6m->in6m_timer)
214 * In Idle Listener state, our timer is not running (in6m->in6m_timer==0)
215 *
216 * The flag is in6m->in6m_state, it is set to MLD_OTHERLISTENER if
217 * we have heard a report from another member, or MLD_IREPORTEDLAST
218 * if we sent the last report.
219 */
220 switch(mldh->mld_type) {
221 case MLD_LISTENER_QUERY:
222 if (ifp->if_flags & IFF_LOOPBACK)
223 break;
224
225 if (!IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) &&
226 !IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
227 break; /* print error or log stat? */
228 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
229 mldh->mld_addr.s6_addr16[1] =
230 htons(ifp->if_index); /* XXX */
231
232 /*
233 * - Start the timers in all of our membership records
234 * that the query applies to for the interface on
235 * which the query arrived excl. those that belong
236 * to the "all-nodes" group (ff02::1).
237 * - Restart any timer that is already running but has
238 * A value longer than the requested timeout.
239 * - Use the value specified in the query message as
240 * the maximum timeout.
241 */
242 IFP_TO_IA6(ifp, ia);
243 if (ia == NULL)
244 break;
245
246 /*
247 * XXX: System timer resolution is too low to handle Max
248 * Response Delay, so set 1 to the internal timer even if
249 * the calculated value equals to zero when Max Response
250 * Delay is positive.
251 */
252 timer = ntohs(mldh->mld_maxdelay)*PR_FASTHZ/MLD_TIMER_SCALE;
253 if (timer == 0 && mldh->mld_maxdelay)
254 timer = 1;
255 mld_all_nodes_linklocal.s6_addr16[1] =
256 htons(ifp->if_index); /* XXX */
257
258 LIST_FOREACH(in6m, &ia->ia6_multiaddrs, in6m_entry) {
259 if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr,
260 &mld_all_nodes_linklocal) ||
261 IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
262 IPV6_ADDR_SCOPE_LINKLOCAL)
263 continue;
264
265 if (IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) ||
266 IN6_ARE_ADDR_EQUAL(&mldh->mld_addr,
267 &in6m->in6m_addr))
268 {
269 if (timer == 0) {
270 /* send a report immediately */
271 mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
272 NULL);
273 in6m->in6m_timer = 0; /* reset timer */
274 in6m->in6m_state = MLD_IREPORTEDLAST;
275 } else if (in6m->in6m_timer == 0 || /* idle */
276 in6m->in6m_timer > timer) {
277 in6m->in6m_timer =
278 MLD_RANDOM_DELAY(timer);
279 mld_timers_are_running = 1;
280 }
281 }
282 }
283
284 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
285 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
286 break;
287 case MLD_LISTENER_REPORT:
288 /*
289 * For fast leave to work, we have to know that we are the
290 * last person to send a report for this group. Reports
291 * can potentially get looped back if we are a multicast
292 * router, so discard reports sourced by me.
293 * Note that it is impossible to check IFF_LOOPBACK flag of
294 * ifp for this purpose, since ip6_mloopback pass the physical
295 * interface to looutput.
296 */
297 if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
298 break;
299
300 if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
301 break;
302
303 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
304 mldh->mld_addr.s6_addr16[1] =
305 htons(ifp->if_index); /* XXX */
306 /*
307 * If we belong to the group being reported, stop
308 * our timer for that group.
309 */
310 IN6_LOOKUP_MULTI(mldh->mld_addr, ifp, in6m);
311 if (in6m) {
312 in6m->in6m_timer = 0; /* transit to idle state */
313 in6m->in6m_state = MLD_OTHERLISTENER; /* clear flag */
314 }
315
316 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
317 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
318 break;
319 default: /* this is impossible */
320 #if 0
321 /*
322 * this case should be impossible because of filtering in
323 * icmp6_input(). But we explicitly disabled this part
324 * just in case.
325 */
326 log(LOG_ERR, "mld_input: illegal type(%d)", mldh->mld_type);
327 #endif
328 break;
329 }
330
331 m_freem(m);
332 }
333
334 void
335 mld6_fasttimeo()
336 {
337 struct in6_multi *in6m;
338 struct in6_multistep step;
339 int s;
340
341 /*
342 * Quick check to see if any work needs to be done, in order
343 * to minimize the overhead of fasttimo processing.
344 */
345 if (!mld_timers_are_running)
346 return;
347
348 s = splsoftnet();
349 mld_timers_are_running = 0;
350 IN6_FIRST_MULTI(step, in6m);
351 while (in6m != NULL) {
352 if (in6m->in6m_timer == 0) {
353 /* do nothing */
354 } else if (--in6m->in6m_timer == 0) {
355 mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
356 in6m->in6m_state = MLD_IREPORTEDLAST;
357 } else {
358 mld_timers_are_running = 1;
359 }
360 IN6_NEXT_MULTI(step, in6m);
361 }
362 splx(s);
363 }
364
365 static void
366 mld6_sendpkt(in6m, type, dst)
367 struct in6_multi *in6m;
368 int type;
369 const struct in6_addr *dst;
370 {
371 struct mbuf *mh, *md;
372 struct mld_hdr *mldh;
373 struct ip6_hdr *ip6;
374 struct ip6_moptions im6o;
375 struct in6_ifaddr *ia;
376 struct ifnet *ifp = in6m->in6m_ifp;
377 int ignflags;
378
379 /*
380 * At first, find a link local address on the outgoing interface
381 * to use as the source address of the MLD packet.
382 * We do not reject tentative addresses for MLD report to deal with
383 * the case where we first join a link-local address.
384 */
385 ignflags = (IN6_IFF_NOTREADY|IN6_IFF_ANYCAST) & ~IN6_IFF_TENTATIVE;
386 if ((ia = in6ifa_ifpforlinklocal(ifp, ignflags)) == NULL)
387 return;
388 if ((ia->ia6_flags & IN6_IFF_TENTATIVE))
389 ia = NULL;
390
391 /*
392 * Allocate mbufs to store ip6 header and MLD header.
393 * We allocate 2 mbufs and make chain in advance because
394 * it is more convenient when inserting the hop-by-hop option later.
395 */
396 MGETHDR(mh, M_DONTWAIT, MT_HEADER);
397 if (mh == NULL)
398 return;
399 MGET(md, M_DONTWAIT, MT_DATA);
400 if (md == NULL) {
401 m_free(mh);
402 return;
403 }
404 mh->m_next = md;
405
406 mh->m_pkthdr.rcvif = NULL;
407 mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
408 mh->m_len = sizeof(struct ip6_hdr);
409 MH_ALIGN(mh, sizeof(struct ip6_hdr));
410
411 /* fill in the ip6 header */
412 ip6 = mtod(mh, struct ip6_hdr *);
413 ip6->ip6_flow = 0;
414 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
415 ip6->ip6_vfc |= IPV6_VERSION;
416 /* ip6_plen will be set later */
417 ip6->ip6_nxt = IPPROTO_ICMPV6;
418 /* ip6_hlim will be set by im6o.im6o_multicast_hlim */
419 ip6->ip6_src = ia ? ia->ia_addr.sin6_addr : in6addr_any;
420 ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
421
422 /* fill in the MLD header */
423 md->m_len = sizeof(struct mld_hdr);
424 mldh = mtod(md, struct mld_hdr *);
425 mldh->mld_type = type;
426 mldh->mld_code = 0;
427 mldh->mld_cksum = 0;
428 /* XXX: we assume the function will not be called for query messages */
429 mldh->mld_maxdelay = 0;
430 mldh->mld_reserved = 0;
431 mldh->mld_addr = in6m->in6m_addr;
432 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
433 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
434 mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
435 sizeof(struct mld_hdr));
436
437 /* construct multicast option */
438 bzero(&im6o, sizeof(im6o));
439 im6o.im6o_multicast_ifp = ifp;
440 im6o.im6o_multicast_hlim = 1;
441
442 /*
443 * Request loopback of the report if we are acting as a multicast
444 * router, so that the process-level routing daemon can hear it.
445 */
446 #ifdef MROUTING
447 im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
448 #endif
449
450 /* increment output statictics */
451 icmp6stat.icp6s_outhist[type]++;
452 icmp6_ifstat_inc(ifp, ifs6_out_msg);
453 switch (type) {
454 case MLD_LISTENER_QUERY:
455 icmp6_ifstat_inc(ifp, ifs6_out_mldquery);
456 break;
457 case MLD_LISTENER_REPORT:
458 icmp6_ifstat_inc(ifp, ifs6_out_mldreport);
459 break;
460 case MLD_LISTENER_DONE:
461 icmp6_ifstat_inc(ifp, ifs6_out_mlddone);
462 break;
463 }
464
465 ip6_output(mh, &ip6_opts, NULL, ia ? 0 : IPV6_UNSPECSRC, &im6o, NULL,
466 NULL);
467 }