1 /* $OpenBSD: mld6.c,v 1.19 2003/06/11 02:54:02 itojun 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
mld6_init()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_RTALERT;
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 /* We will specify the hoplimit by a multicast option. */
126 ip6_opts.ip6po_hlim = -1;
127 }
128
129 void
mld6_start_listening(in6m)130 mld6_start_listening(in6m)
131 struct in6_multi *in6m;
132 {
133 int s = splsoftnet();
134
135 /*
136 * RFC2710 page 10:
137 * The node never sends a Report or Done for the link-scope all-nodes
138 * address.
139 * MLD messages are never sent for multicast addresses whose scope is 0
140 * (reserved) or 1 (node-local).
141 */
142 mld_all_nodes_linklocal.s6_addr16[1] =
143 htons(in6m->in6m_ifp->if_index); /* XXX */
144 if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld_all_nodes_linklocal) ||
145 IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) < IPV6_ADDR_SCOPE_LINKLOCAL) {
146 in6m->in6m_timer = 0;
147 in6m->in6m_state = MLD_OTHERLISTENER;
148 } else {
149 mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
150 in6m->in6m_timer =
151 MLD_RANDOM_DELAY(MLD_UNSOLICITED_REPORT_INTERVAL *
152 PR_FASTHZ);
153 in6m->in6m_state = MLD_IREPORTEDLAST;
154 mld_timers_are_running = 1;
155 }
156 splx(s);
157 }
158
159 void
mld6_stop_listening(in6m)160 mld6_stop_listening(in6m)
161 struct in6_multi *in6m;
162 {
163 mld_all_nodes_linklocal.s6_addr16[1] =
164 htons(in6m->in6m_ifp->if_index); /* XXX */
165 mld_all_routers_linklocal.s6_addr16[1] =
166 htons(in6m->in6m_ifp->if_index); /* XXX: necessary when mrouting */
167
168 if (in6m->in6m_state == MLD_IREPORTEDLAST &&
169 (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld_all_nodes_linklocal)) &&
170 IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) > IPV6_ADDR_SCOPE_NODELOCAL)
171 mld6_sendpkt(in6m, MLD_LISTENER_DONE,
172 &mld_all_routers_linklocal);
173 }
174
175 void
mld6_input(m,off)176 mld6_input(m, off)
177 struct mbuf *m;
178 int off;
179 {
180 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
181 struct mld_hdr *mldh;
182 struct ifnet *ifp = m->m_pkthdr.rcvif;
183 struct in6_multi *in6m;
184 struct in6_ifaddr *ia;
185 int timer; /* timer value in the MLD query header */
186
187 IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
188 if (mldh == NULL) {
189 icmp6stat.icp6s_tooshort++;
190 return;
191 }
192
193 /* source address validation */
194 ip6 = mtod(m, struct ip6_hdr *);/* in case mpullup */
195 if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
196 #if 0
197 log(LOG_ERR,
198 "mld_input: src %s is not link-local (grp=%s)\n",
199 ip6_sprintf(&ip6->ip6_src),
200 ip6_sprintf(&mldh->mld_addr));
201 #endif
202 /*
203 * spec (RFC2710) does not explicitly
204 * specify to discard the packet from a non link-local
205 * source address. But we believe it's expected to do so.
206 */
207 m_freem(m);
208 return;
209 }
210
211 /*
212 * In the MLD6 specification, there are 3 states and a flag.
213 *
214 * In Non-Listener state, we simply don't have a membership record.
215 * In Delaying Listener state, our timer is running (in6m->in6m_timer)
216 * In Idle Listener state, our timer is not running (in6m->in6m_timer==0)
217 *
218 * The flag is in6m->in6m_state, it is set to MLD_OTHERLISTENER if
219 * we have heard a report from another member, or MLD_IREPORTEDLAST
220 * if we sent the last report.
221 */
222 switch(mldh->mld_type) {
223 case MLD_LISTENER_QUERY:
224 if (ifp->if_flags & IFF_LOOPBACK)
225 break;
226
227 if (!IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) &&
228 !IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
229 break; /* print error or log stat? */
230 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
231 mldh->mld_addr.s6_addr16[1] =
232 htons(ifp->if_index); /* XXX */
233
234 /*
235 * - Start the timers in all of our membership records
236 * that the query applies to for the interface on
237 * which the query arrived excl. those that belong
238 * to the "all-nodes" group (ff02::1).
239 * - Restart any timer that is already running but has
240 * A value longer than the requested timeout.
241 * - Use the value specified in the query message as
242 * the maximum timeout.
243 */
244 IFP_TO_IA6(ifp, ia);
245 if (ia == NULL)
246 break;
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 mld_all_nodes_linklocal.s6_addr16[1] =
258 htons(ifp->if_index); /* XXX */
259
260 for (in6m = ia->ia6_multiaddrs.lh_first;
261 in6m;
262 in6m = in6m->in6m_entry.le_next)
263 {
264 if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr,
265 &mld_all_nodes_linklocal) ||
266 IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
267 IPV6_ADDR_SCOPE_LINKLOCAL)
268 continue;
269
270 if (IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) ||
271 IN6_ARE_ADDR_EQUAL(&mldh->mld_addr,
272 &in6m->in6m_addr))
273 {
274 if (timer == 0) {
275 /* send a report immediately */
276 mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
277 NULL);
278 in6m->in6m_timer = 0; /* reset timer */
279 in6m->in6m_state = MLD_IREPORTEDLAST;
280 } else if (in6m->in6m_timer == 0 || /* idle */
281 in6m->in6m_timer > timer) {
282 in6m->in6m_timer =
283 MLD_RANDOM_DELAY(timer);
284 mld_timers_are_running = 1;
285 }
286 }
287 }
288
289 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
290 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
291 break;
292 case MLD_LISTENER_REPORT:
293 /*
294 * For fast leave to work, we have to know that we are the
295 * last person to send a report for this group. Reports
296 * can potentially get looped back if we are a multicast
297 * router, so discard reports sourced by me.
298 * Note that it is impossible to check IFF_LOOPBACK flag of
299 * ifp for this purpose, since ip6_mloopback pass the physical
300 * interface to looutput.
301 */
302 if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
303 break;
304
305 if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
306 break;
307
308 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
309 mldh->mld_addr.s6_addr16[1] =
310 htons(ifp->if_index); /* XXX */
311 /*
312 * If we belong to the group being reported, stop
313 * our timer for that group.
314 */
315 IN6_LOOKUP_MULTI(mldh->mld_addr, ifp, in6m);
316 if (in6m) {
317 in6m->in6m_timer = 0; /* transit to idle state */
318 in6m->in6m_state = MLD_OTHERLISTENER; /* clear flag */
319 }
320
321 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
322 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
323 break;
324 default: /* this is impossible */
325 #if 0
326 /*
327 * this case should be impossible because of filtering in
328 * icmp6_input(). But we explicitly disabled this part
329 * just in case.
330 */
331 log(LOG_ERR, "mld_input: illegal type(%d)", mldh->mld_type);
332 #endif
333 break;
334 }
335
336 m_freem(m);
337 }
338
339 void
mld6_fasttimeo()340 mld6_fasttimeo()
341 {
342 struct in6_multi *in6m;
343 struct in6_multistep step;
344 int s;
345
346 /*
347 * Quick check to see if any work needs to be done, in order
348 * to minimize the overhead of fasttimo processing.
349 */
350 if (!mld_timers_are_running)
351 return;
352
353 s = splsoftnet();
354 mld_timers_are_running = 0;
355 IN6_FIRST_MULTI(step, in6m);
356 while (in6m != NULL) {
357 if (in6m->in6m_timer == 0) {
358 /* do nothing */
359 } else if (--in6m->in6m_timer == 0) {
360 mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
361 in6m->in6m_state = MLD_IREPORTEDLAST;
362 } else {
363 mld_timers_are_running = 1;
364 }
365 IN6_NEXT_MULTI(step, in6m);
366 }
367 splx(s);
368 }
369
370 static void
mld6_sendpkt(in6m,type,dst)371 mld6_sendpkt(in6m, type, dst)
372 struct in6_multi *in6m;
373 int type;
374 const struct in6_addr *dst;
375 {
376 struct mbuf *mh, *md;
377 struct mld_hdr *mldh;
378 struct ip6_hdr *ip6;
379 struct ip6_moptions im6o;
380 struct in6_ifaddr *ia;
381 struct ifnet *ifp = in6m->in6m_ifp;
382 int ignflags;
383
384 /*
385 * At first, find a link local address on the outgoing interface
386 * to use as the source address of the MLD packet.
387 * We do not reject tentative addresses for MLD report to deal with
388 * the case where we first join a link-local address.
389 */
390 ignflags = (IN6_IFF_NOTREADY|IN6_IFF_ANYCAST) & ~IN6_IFF_TENTATIVE;
391 if ((ia = in6ifa_ifpforlinklocal(ifp, ignflags)) == NULL)
392 return;
393 if ((ia->ia6_flags & IN6_IFF_TENTATIVE))
394 ia = NULL;
395
396 /*
397 * Allocate mbufs to store ip6 header and MLD header.
398 * We allocate 2 mbufs and make chain in advance because
399 * it is more convenient when inserting the hop-by-hop option later.
400 */
401 MGETHDR(mh, M_DONTWAIT, MT_HEADER);
402 if (mh == NULL)
403 return;
404 MGET(md, M_DONTWAIT, MT_DATA);
405 if (md == NULL) {
406 m_free(mh);
407 return;
408 }
409 mh->m_next = md;
410
411 mh->m_pkthdr.rcvif = NULL;
412 mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
413 mh->m_len = sizeof(struct ip6_hdr);
414 MH_ALIGN(mh, sizeof(struct ip6_hdr));
415
416 /* fill in the ip6 header */
417 ip6 = mtod(mh, struct ip6_hdr *);
418 ip6->ip6_flow = 0;
419 ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
420 ip6->ip6_vfc |= IPV6_VERSION;
421 /* ip6_plen will be set later */
422 ip6->ip6_nxt = IPPROTO_ICMPV6;
423 /* ip6_hlim will be set by im6o.im6o_multicast_hlim */
424 ip6->ip6_src = ia ? ia->ia_addr.sin6_addr : in6addr_any;
425 ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
426
427 /* fill in the MLD header */
428 md->m_len = sizeof(struct mld_hdr);
429 mldh = mtod(md, struct mld_hdr *);
430 mldh->mld_type = type;
431 mldh->mld_code = 0;
432 mldh->mld_cksum = 0;
433 /* XXX: we assume the function will not be called for query messages */
434 mldh->mld_maxdelay = 0;
435 mldh->mld_reserved = 0;
436 mldh->mld_addr = in6m->in6m_addr;
437 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
438 mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
439 mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, 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 icmp6_ifstat_inc(ifp, ifs6_out_msg);
456 switch (type) {
457 case MLD_LISTENER_QUERY:
458 icmp6_ifstat_inc(ifp, ifs6_out_mldquery);
459 break;
460 case MLD_LISTENER_REPORT:
461 icmp6_ifstat_inc(ifp, ifs6_out_mldreport);
462 break;
463 case MLD_LISTENER_DONE:
464 icmp6_ifstat_inc(ifp, ifs6_out_mlddone);
465 break;
466 }
467
468 ip6_output(mh, &ip6_opts, NULL, ia ? 0 : IPV6_UNSPECSRC, &im6o, NULL);
469 }
470