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1 office 1 /**
2 * @file
3 * Multicast listener discovery
4 *
5 * @defgroup mld6 MLD6
6 * @ingroup ip6
7 * Multicast listener discovery for IPv6. Aims to be compliant with RFC 2710.
8 * No support for MLDv2.\n
9 * To be called from TCPIP thread
10 */
11  
12 /*
13 * Copyright (c) 2010 Inico Technologies Ltd.
14 * All rights reserved.
15 *
16 * Redistribution and use in source and binary forms, with or without modification,
17 * are permitted provided that the following conditions are met:
18 *
19 * 1. Redistributions of source code must retain the above copyright notice,
20 * this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright notice,
22 * this list of conditions and the following disclaimer in the documentation
23 * and/or other materials provided with the distribution.
24 * 3. The name of the author may not be used to endorse or promote products
25 * derived from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
28 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
29 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
30 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
32 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
35 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
36 * OF SUCH DAMAGE.
37 *
38 * This file is part of the lwIP TCP/IP stack.
39 *
40 * Author: Ivan Delamer <delamer@inicotech.com>
41 *
42 *
43 * Please coordinate changes and requests with Ivan Delamer
44 * <delamer@inicotech.com>
45 */
46  
47 /* Based on igmp.c implementation of igmp v2 protocol */
48  
49 #include "lwip/opt.h"
50  
51 #if LWIP_IPV6 && LWIP_IPV6_MLD /* don't build if not configured for use in lwipopts.h */
52  
53 #include "lwip/mld6.h"
54 #include "lwip/prot/mld6.h"
55 #include "lwip/icmp6.h"
56 #include "lwip/ip6.h"
57 #include "lwip/ip6_addr.h"
58 #include "lwip/ip.h"
59 #include "lwip/inet_chksum.h"
60 #include "lwip/pbuf.h"
61 #include "lwip/netif.h"
62 #include "lwip/memp.h"
63 #include "lwip/stats.h"
64  
65 #include <string.h>
66  
67  
68 /*
69 * MLD constants
70 */
71 #define MLD6_HL 1
72 #define MLD6_JOIN_DELAYING_MEMBER_TMR_MS (500)
73  
74 #define MLD6_GROUP_NON_MEMBER 0
75 #define MLD6_GROUP_DELAYING_MEMBER 1
76 #define MLD6_GROUP_IDLE_MEMBER 2
77  
78 /* Forward declarations. */
79 static struct mld_group *mld6_new_group(struct netif *ifp, const ip6_addr_t *addr);
80 static err_t mld6_remove_group(struct netif *netif, struct mld_group *group);
81 static void mld6_delayed_report(struct mld_group *group, u16_t maxresp);
82 static void mld6_send(struct netif *netif, struct mld_group *group, u8_t type);
83  
84  
85 /**
86 * Stop MLD processing on interface
87 *
88 * @param netif network interface on which stop MLD processing
89 */
90 err_t
91 mld6_stop(struct netif *netif)
92 {
93 struct mld_group *group = netif_mld6_data(netif);
94  
95 netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_MLD6, NULL);
96  
97 while (group != NULL) {
98 struct mld_group *next = group->next; /* avoid use-after-free below */
99  
100 /* disable the group at the MAC level */
101 if (netif->mld_mac_filter != NULL) {
102 netif->mld_mac_filter(netif, &(group->group_address), NETIF_DEL_MAC_FILTER);
103 }
104  
105 /* free group */
106 memp_free(MEMP_MLD6_GROUP, group);
107  
108 /* move to "next" */
109 group = next;
110 }
111 return ERR_OK;
112 }
113  
114 /**
115 * Report MLD memberships for this interface
116 *
117 * @param netif network interface on which report MLD memberships
118 */
119 void
120 mld6_report_groups(struct netif *netif)
121 {
122 struct mld_group *group = netif_mld6_data(netif);
123  
124 while (group != NULL) {
125 mld6_delayed_report(group, MLD6_JOIN_DELAYING_MEMBER_TMR_MS);
126 group = group->next;
127 }
128 }
129  
130 /**
131 * Search for a group that is joined on a netif
132 *
133 * @param ifp the network interface for which to look
134 * @param addr the group ipv6 address to search for
135 * @return a struct mld_group* if the group has been found,
136 * NULL if the group wasn't found.
137 */
138 struct mld_group *
139 mld6_lookfor_group(struct netif *ifp, const ip6_addr_t *addr)
140 {
141 struct mld_group *group = netif_mld6_data(ifp);
142  
143 while (group != NULL) {
144 if (ip6_addr_cmp(&(group->group_address), addr)) {
145 return group;
146 }
147 group = group->next;
148 }
149  
150 return NULL;
151 }
152  
153  
154 /**
155 * create a new group
156 *
157 * @param ifp the network interface for which to create
158 * @param addr the new group ipv6
159 * @return a struct mld_group*,
160 * NULL on memory error.
161 */
162 static struct mld_group *
163 mld6_new_group(struct netif *ifp, const ip6_addr_t *addr)
164 {
165 struct mld_group *group;
166  
167 group = (struct mld_group *)memp_malloc(MEMP_MLD6_GROUP);
168 if (group != NULL) {
169 ip6_addr_set(&(group->group_address), addr);
170 group->timer = 0; /* Not running */
171 group->group_state = MLD6_GROUP_IDLE_MEMBER;
172 group->last_reporter_flag = 0;
173 group->use = 0;
174 group->next = netif_mld6_data(ifp);
175  
176 netif_set_client_data(ifp, LWIP_NETIF_CLIENT_DATA_INDEX_MLD6, group);
177 }
178  
179 return group;
180 }
181  
182 /**
183 * Remove a group from the mld_group_list, but do not free it yet
184 *
185 * @param group the group to remove
186 * @return ERR_OK if group was removed from the list, an err_t otherwise
187 */
188 static err_t
189 mld6_remove_group(struct netif *netif, struct mld_group *group)
190 {
191 err_t err = ERR_OK;
192  
193 /* Is it the first group? */
194 if (netif_mld6_data(netif) == group) {
195 netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_MLD6, group->next);
196 } else {
197 /* look for group further down the list */
198 struct mld_group *tmpGroup;
199 for (tmpGroup = netif_mld6_data(netif); tmpGroup != NULL; tmpGroup = tmpGroup->next) {
200 if (tmpGroup->next == group) {
201 tmpGroup->next = group->next;
202 break;
203 }
204 }
205 /* Group not find group */
206 if (tmpGroup == NULL) {
207 err = ERR_ARG;
208 }
209 }
210  
211 return err;
212 }
213  
214  
215 /**
216 * Process an input MLD message. Called by icmp6_input.
217 *
218 * @param p the mld packet, p->payload pointing to the icmpv6 header
219 * @param inp the netif on which this packet was received
220 */
221 void
222 mld6_input(struct pbuf *p, struct netif *inp)
223 {
224 struct mld_header *mld_hdr;
225 struct mld_group *group;
226  
227 MLD6_STATS_INC(mld6.recv);
228  
229 /* Check that mld header fits in packet. */
230 if (p->len < sizeof(struct mld_header)) {
231 /* @todo debug message */
232 pbuf_free(p);
233 MLD6_STATS_INC(mld6.lenerr);
234 MLD6_STATS_INC(mld6.drop);
235 return;
236 }
237  
238 mld_hdr = (struct mld_header *)p->payload;
239  
240 switch (mld_hdr->type) {
241 case ICMP6_TYPE_MLQ: /* Multicast listener query. */
242 /* Is it a general query? */
243 if (ip6_addr_isallnodes_linklocal(ip6_current_dest_addr()) &&
244 ip6_addr_isany(&(mld_hdr->multicast_address))) {
245 MLD6_STATS_INC(mld6.rx_general);
246 /* Report all groups, except all nodes group, and if-local groups. */
247 group = netif_mld6_data(inp);
248 while (group != NULL) {
249 if ((!(ip6_addr_ismulticast_iflocal(&(group->group_address)))) &&
250 (!(ip6_addr_isallnodes_linklocal(&(group->group_address))))) {
251 mld6_delayed_report(group, mld_hdr->max_resp_delay);
252 }
253 group = group->next;
254 }
255 } else {
256 /* Have we joined this group?
257 * We use IP6 destination address to have a memory aligned copy.
258 * mld_hdr->multicast_address should be the same. */
259 MLD6_STATS_INC(mld6.rx_group);
260 group = mld6_lookfor_group(inp, ip6_current_dest_addr());
261 if (group != NULL) {
262 /* Schedule a report. */
263 mld6_delayed_report(group, mld_hdr->max_resp_delay);
264 }
265 }
266 break; /* ICMP6_TYPE_MLQ */
267 case ICMP6_TYPE_MLR: /* Multicast listener report. */
268 /* Have we joined this group?
269 * We use IP6 destination address to have a memory aligned copy.
270 * mld_hdr->multicast_address should be the same. */
271 MLD6_STATS_INC(mld6.rx_report);
272 group = mld6_lookfor_group(inp, ip6_current_dest_addr());
273 if (group != NULL) {
274 /* If we are waiting to report, cancel it. */
275 if (group->group_state == MLD6_GROUP_DELAYING_MEMBER) {
276 group->timer = 0; /* stopped */
277 group->group_state = MLD6_GROUP_IDLE_MEMBER;
278 group->last_reporter_flag = 0;
279 }
280 }
281 break; /* ICMP6_TYPE_MLR */
282 case ICMP6_TYPE_MLD: /* Multicast listener done. */
283 /* Do nothing, router will query us. */
284 break; /* ICMP6_TYPE_MLD */
285 default:
286 MLD6_STATS_INC(mld6.proterr);
287 MLD6_STATS_INC(mld6.drop);
288 break;
289 }
290  
291 pbuf_free(p);
292 }
293  
294 /**
295 * @ingroup mld6
296 * Join a group on one or all network interfaces.
297 *
298 * If the group is to be joined on all interfaces, the given group address must
299 * not have a zone set (i.e., it must have its zone index set to IP6_NO_ZONE).
300 * If the group is to be joined on one particular interface, the given group
301 * address may or may not have a zone set.
302 *
303 * @param srcaddr ipv6 address (zoned) of the network interface which should
304 * join a new group. If IP6_ADDR_ANY6, join on all netifs
305 * @param groupaddr the ipv6 address of the group to join (possibly but not
306 * necessarily zoned)
307 * @return ERR_OK if group was joined on the netif(s), an err_t otherwise
308 */
309 err_t
310 mld6_joingroup(const ip6_addr_t *srcaddr, const ip6_addr_t *groupaddr)
311 {
312 err_t err = ERR_VAL; /* no matching interface */
313 struct netif *netif;
314  
315 /* loop through netif's */
316 NETIF_FOREACH(netif) {
317 /* Should we join this interface ? */
318 if (ip6_addr_isany(srcaddr) ||
319 netif_get_ip6_addr_match(netif, srcaddr) >= 0) {
320 err = mld6_joingroup_netif(netif, groupaddr);
321 if (err != ERR_OK) {
322 return err;
323 }
324 }
325 }
326  
327 return err;
328 }
329  
330 /**
331 * @ingroup mld6
332 * Join a group on a network interface.
333 *
334 * @param netif the network interface which should join a new group.
335 * @param groupaddr the ipv6 address of the group to join (possibly but not
336 * necessarily zoned)
337 * @return ERR_OK if group was joined on the netif, an err_t otherwise
338 */
339 err_t
340 mld6_joingroup_netif(struct netif *netif, const ip6_addr_t *groupaddr)
341 {
342 struct mld_group *group;
343 #if LWIP_IPV6_SCOPES
344 ip6_addr_t ip6addr;
345  
346 /* If the address has a particular scope but no zone set, use the netif to
347 * set one now. Within the mld6 module, all addresses are properly zoned. */
348 if (ip6_addr_lacks_zone(groupaddr, IP6_MULTICAST)) {
349 ip6_addr_set(&ip6addr, groupaddr);
350 ip6_addr_assign_zone(&ip6addr, IP6_MULTICAST, netif);
351 groupaddr = &ip6addr;
352 }
353 IP6_ADDR_ZONECHECK_NETIF(groupaddr, netif);
354 #endif /* LWIP_IPV6_SCOPES */
355  
356 /* find group or create a new one if not found */
357 group = mld6_lookfor_group(netif, groupaddr);
358  
359 if (group == NULL) {
360 /* Joining a new group. Create a new group entry. */
361 group = mld6_new_group(netif, groupaddr);
362 if (group == NULL) {
363 return ERR_MEM;
364 }
365  
366 /* Activate this address on the MAC layer. */
367 if (netif->mld_mac_filter != NULL) {
368 netif->mld_mac_filter(netif, groupaddr, NETIF_ADD_MAC_FILTER);
369 }
370  
371 /* Report our membership. */
372 MLD6_STATS_INC(mld6.tx_report);
373 mld6_send(netif, group, ICMP6_TYPE_MLR);
374 mld6_delayed_report(group, MLD6_JOIN_DELAYING_MEMBER_TMR_MS);
375 }
376  
377 /* Increment group use */
378 group->use++;
379 return ERR_OK;
380 }
381  
382 /**
383 * @ingroup mld6
384 * Leave a group on a network interface.
385 *
386 * Zoning of address follows the same rules as @ref mld6_joingroup.
387 *
388 * @param srcaddr ipv6 address (zoned) of the network interface which should
389 * leave the group. If IP6_ADDR_ANY6, leave on all netifs
390 * @param groupaddr the ipv6 address of the group to leave (possibly, but not
391 * necessarily zoned)
392 * @return ERR_OK if group was left on the netif(s), an err_t otherwise
393 */
394 err_t
395 mld6_leavegroup(const ip6_addr_t *srcaddr, const ip6_addr_t *groupaddr)
396 {
397 err_t err = ERR_VAL; /* no matching interface */
398 struct netif *netif;
399  
400 /* loop through netif's */
401 NETIF_FOREACH(netif) {
402 /* Should we leave this interface ? */
403 if (ip6_addr_isany(srcaddr) ||
404 netif_get_ip6_addr_match(netif, srcaddr) >= 0) {
405 err_t res = mld6_leavegroup_netif(netif, groupaddr);
406 if (err != ERR_OK) {
407 /* Store this result if we have not yet gotten a success */
408 err = res;
409 }
410 }
411 }
412  
413 return err;
414 }
415  
416 /**
417 * @ingroup mld6
418 * Leave a group on a network interface.
419 *
420 * @param netif the network interface which should leave the group.
421 * @param groupaddr the ipv6 address of the group to leave (possibly, but not
422 * necessarily zoned)
423 * @return ERR_OK if group was left on the netif, an err_t otherwise
424 */
425 err_t
426 mld6_leavegroup_netif(struct netif *netif, const ip6_addr_t *groupaddr)
427 {
428 struct mld_group *group;
429 #if LWIP_IPV6_SCOPES
430 ip6_addr_t ip6addr;
431  
432 if (ip6_addr_lacks_zone(groupaddr, IP6_MULTICAST)) {
433 ip6_addr_set(&ip6addr, groupaddr);
434 ip6_addr_assign_zone(&ip6addr, IP6_MULTICAST, netif);
435 groupaddr = &ip6addr;
436 }
437 IP6_ADDR_ZONECHECK_NETIF(groupaddr, netif);
438 #endif /* LWIP_IPV6_SCOPES */
439  
440 /* find group */
441 group = mld6_lookfor_group(netif, groupaddr);
442  
443 if (group != NULL) {
444 /* Leave if there is no other use of the group */
445 if (group->use <= 1) {
446 /* Remove the group from the list */
447 mld6_remove_group(netif, group);
448  
449 /* If we are the last reporter for this group */
450 if (group->last_reporter_flag) {
451 MLD6_STATS_INC(mld6.tx_leave);
452 mld6_send(netif, group, ICMP6_TYPE_MLD);
453 }
454  
455 /* Disable the group at the MAC level */
456 if (netif->mld_mac_filter != NULL) {
457 netif->mld_mac_filter(netif, groupaddr, NETIF_DEL_MAC_FILTER);
458 }
459  
460 /* free group struct */
461 memp_free(MEMP_MLD6_GROUP, group);
462 } else {
463 /* Decrement group use */
464 group->use--;
465 }
466  
467 /* Left group */
468 return ERR_OK;
469 }
470  
471 /* Group not found */
472 return ERR_VAL;
473 }
474  
475  
476 /**
477 * Periodic timer for mld processing. Must be called every
478 * MLD6_TMR_INTERVAL milliseconds (100).
479 *
480 * When a delaying member expires, a membership report is sent.
481 */
482 void
483 mld6_tmr(void)
484 {
485 struct netif *netif;
486  
487 NETIF_FOREACH(netif) {
488 struct mld_group *group = netif_mld6_data(netif);
489  
490 while (group != NULL) {
491 if (group->timer > 0) {
492 group->timer--;
493 if (group->timer == 0) {
494 /* If the state is MLD6_GROUP_DELAYING_MEMBER then we send a report for this group */
495 if (group->group_state == MLD6_GROUP_DELAYING_MEMBER) {
496 MLD6_STATS_INC(mld6.tx_report);
497 mld6_send(netif, group, ICMP6_TYPE_MLR);
498 group->group_state = MLD6_GROUP_IDLE_MEMBER;
499 }
500 }
501 }
502 group = group->next;
503 }
504 }
505 }
506  
507 /**
508 * Schedule a delayed membership report for a group
509 *
510 * @param group the mld_group for which "delaying" membership report
511 * should be sent
512 * @param maxresp_in the max resp delay provided in the query
513 */
514 static void
515 mld6_delayed_report(struct mld_group *group, u16_t maxresp_in)
516 {
517 /* Convert maxresp from milliseconds to tmr ticks */
518 u16_t maxresp = maxresp_in / MLD6_TMR_INTERVAL;
519 if (maxresp == 0) {
520 maxresp = 1;
521 }
522  
523 #ifdef LWIP_RAND
524 /* Randomize maxresp. (if LWIP_RAND is supported) */
525 maxresp = (u16_t)(LWIP_RAND() % maxresp);
526 if (maxresp == 0) {
527 maxresp = 1;
528 }
529 #endif /* LWIP_RAND */
530  
531 /* Apply timer value if no report has been scheduled already. */
532 if ((group->group_state == MLD6_GROUP_IDLE_MEMBER) ||
533 ((group->group_state == MLD6_GROUP_DELAYING_MEMBER) &&
534 ((group->timer == 0) || (maxresp < group->timer)))) {
535 group->timer = maxresp;
536 group->group_state = MLD6_GROUP_DELAYING_MEMBER;
537 }
538 }
539  
540 /**
541 * Send a MLD message (report or done).
542 *
543 * An IPv6 hop-by-hop options header with a router alert option
544 * is prepended.
545 *
546 * @param group the group to report or quit
547 * @param type ICMP6_TYPE_MLR (report) or ICMP6_TYPE_MLD (done)
548 */
549 static void
550 mld6_send(struct netif *netif, struct mld_group *group, u8_t type)
551 {
552 struct mld_header *mld_hdr;
553 struct pbuf *p;
554 const ip6_addr_t *src_addr;
555  
556 /* Allocate a packet. Size is MLD header + IPv6 Hop-by-hop options header. */
557 p = pbuf_alloc(PBUF_IP, sizeof(struct mld_header) + MLD6_HBH_HLEN, PBUF_RAM);
558 if (p == NULL) {
559 MLD6_STATS_INC(mld6.memerr);
560 return;
561 }
562  
563 /* Move to make room for Hop-by-hop options header. */
564 if (pbuf_remove_header(p, MLD6_HBH_HLEN)) {
565 pbuf_free(p);
566 MLD6_STATS_INC(mld6.lenerr);
567 return;
568 }
569  
570 /* Select our source address. */
571 if (!ip6_addr_isvalid(netif_ip6_addr_state(netif, 0))) {
572 /* This is a special case, when we are performing duplicate address detection.
573 * We must join the multicast group, but we don't have a valid address yet. */
574 src_addr = IP6_ADDR_ANY6;
575 } else {
576 /* Use link-local address as source address. */
577 src_addr = netif_ip6_addr(netif, 0);
578 }
579  
580 /* MLD message header pointer. */
581 mld_hdr = (struct mld_header *)p->payload;
582  
583 /* Set fields. */
584 mld_hdr->type = type;
585 mld_hdr->code = 0;
586 mld_hdr->chksum = 0;
587 mld_hdr->max_resp_delay = 0;
588 mld_hdr->reserved = 0;
589 ip6_addr_copy_to_packed(mld_hdr->multicast_address, group->group_address);
590  
591 #if CHECKSUM_GEN_ICMP6
592 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
593 mld_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len,
594 src_addr, &(group->group_address));
595 }
596 #endif /* CHECKSUM_GEN_ICMP6 */
597  
598 /* Add hop-by-hop headers options: router alert with MLD value. */
599 ip6_options_add_hbh_ra(p, IP6_NEXTH_ICMP6, IP6_ROUTER_ALERT_VALUE_MLD);
600  
601 if (type == ICMP6_TYPE_MLR) {
602 /* Remember we were the last to report */
603 group->last_reporter_flag = 1;
604 }
605  
606 /* Send the packet out. */
607 MLD6_STATS_INC(mld6.xmit);
608 ip6_output_if(p, (ip6_addr_isany(src_addr)) ? NULL : src_addr, &(group->group_address),
609 MLD6_HL, 0, IP6_NEXTH_HOPBYHOP, netif);
610 pbuf_free(p);
611 }
612  
613 #endif /* LWIP_IPV6 */