Annotation of sys/netinet6/mld6.c, Revision 1.1.1.1
1.1 nbrk 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: }
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