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1 office 1 /**
2 * @file
3 *
4 * Neighbor discovery and stateless address autoconfiguration for IPv6.
5 * Aims to be compliant with RFC 4861 (Neighbor discovery) and RFC 4862
6 * (Address autoconfiguration).
7 */
8  
9 /*
10 * Copyright (c) 2010 Inico Technologies Ltd.
11 * All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without modification,
14 * are permitted provided that the following conditions are met:
15 *
16 * 1. Redistributions of source code must retain the above copyright notice,
17 * this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright notice,
19 * this list of conditions and the following disclaimer in the documentation
20 * and/or other materials provided with the distribution.
21 * 3. The name of the author may not be used to endorse or promote products
22 * derived from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
25 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
27 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
28 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
29 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
32 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
33 * OF SUCH DAMAGE.
34 *
35 * This file is part of the lwIP TCP/IP stack.
36 *
37 * Author: Ivan Delamer <delamer@inicotech.com>
38 *
39 *
40 * Please coordinate changes and requests with Ivan Delamer
41 * <delamer@inicotech.com>
42 */
43  
44 #include "lwip/opt.h"
45  
46 #if LWIP_IPV6 /* don't build if not configured for use in lwipopts.h */
47  
48 #include "lwip/nd6.h"
49 #include "lwip/priv/nd6_priv.h"
50 #include "lwip/prot/nd6.h"
51 #include "lwip/prot/icmp6.h"
52 #include "lwip/pbuf.h"
53 #include "lwip/mem.h"
54 #include "lwip/memp.h"
55 #include "lwip/ip6.h"
56 #include "lwip/ip6_addr.h"
57 #include "lwip/inet_chksum.h"
58 #include "lwip/netif.h"
59 #include "lwip/icmp6.h"
60 #include "lwip/mld6.h"
61 #include "lwip/ip.h"
62 #include "lwip/stats.h"
63 #include "lwip/dns.h"
64  
65 #include <string.h>
66  
67 #ifdef LWIP_HOOK_FILENAME
68 #include LWIP_HOOK_FILENAME
69 #endif
70  
71 #if LWIP_IPV6_DUP_DETECT_ATTEMPTS > IP6_ADDR_TENTATIVE_COUNT_MASK
72 #error LWIP_IPV6_DUP_DETECT_ATTEMPTS > IP6_ADDR_TENTATIVE_COUNT_MASK
73 #endif
74  
75 /* Router tables. */
76 struct nd6_neighbor_cache_entry neighbor_cache[LWIP_ND6_NUM_NEIGHBORS];
77 struct nd6_destination_cache_entry destination_cache[LWIP_ND6_NUM_DESTINATIONS];
78 struct nd6_prefix_list_entry prefix_list[LWIP_ND6_NUM_PREFIXES];
79 struct nd6_router_list_entry default_router_list[LWIP_ND6_NUM_ROUTERS];
80  
81 /* Default values, can be updated by a RA message. */
82 u32_t reachable_time = LWIP_ND6_REACHABLE_TIME;
83 u32_t retrans_timer = LWIP_ND6_RETRANS_TIMER; /* @todo implement this value in timer */
84  
85 /* Index for cache entries. */
86 static u8_t nd6_cached_neighbor_index;
87 static u8_t nd6_cached_destination_index;
88  
89 /* Multicast address holder. */
90 static ip6_addr_t multicast_address;
91  
92 /* Static buffer to parse RA packet options */
93 union ra_options {
94 struct lladdr_option lladdr;
95 struct mtu_option mtu;
96 struct prefix_option prefix;
97 #if LWIP_ND6_RDNSS_MAX_DNS_SERVERS
98 struct rdnss_option rdnss;
99 #endif
100 };
101 static union ra_options nd6_ra_buffer;
102  
103 /* Forward declarations. */
104 static s8_t nd6_find_neighbor_cache_entry(const ip6_addr_t *ip6addr);
105 static s8_t nd6_new_neighbor_cache_entry(void);
106 static void nd6_free_neighbor_cache_entry(s8_t i);
107 static s8_t nd6_find_destination_cache_entry(const ip6_addr_t *ip6addr);
108 static s8_t nd6_new_destination_cache_entry(void);
109 static s8_t nd6_is_prefix_in_netif(const ip6_addr_t *ip6addr, struct netif *netif);
110 static s8_t nd6_select_router(const ip6_addr_t *ip6addr, struct netif *netif);
111 static s8_t nd6_get_router(const ip6_addr_t *router_addr, struct netif *netif);
112 static s8_t nd6_new_router(const ip6_addr_t *router_addr, struct netif *netif);
113 static s8_t nd6_get_onlink_prefix(const ip6_addr_t *prefix, struct netif *netif);
114 static s8_t nd6_new_onlink_prefix(const ip6_addr_t *prefix, struct netif *netif);
115 static s8_t nd6_get_next_hop_entry(const ip6_addr_t *ip6addr, struct netif *netif);
116 static err_t nd6_queue_packet(s8_t neighbor_index, struct pbuf *q);
117  
118 #define ND6_SEND_FLAG_MULTICAST_DEST 0x01
119 #define ND6_SEND_FLAG_ALLNODES_DEST 0x02
120 #define ND6_SEND_FLAG_ANY_SRC 0x04
121 static void nd6_send_ns(struct netif *netif, const ip6_addr_t *target_addr, u8_t flags);
122 static void nd6_send_na(struct netif *netif, const ip6_addr_t *target_addr, u8_t flags);
123 static void nd6_send_neighbor_cache_probe(struct nd6_neighbor_cache_entry *entry, u8_t flags);
124 #if LWIP_IPV6_SEND_ROUTER_SOLICIT
125 static err_t nd6_send_rs(struct netif *netif);
126 #endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
127  
128 #if LWIP_ND6_QUEUEING
129 static void nd6_free_q(struct nd6_q_entry *q);
130 #else /* LWIP_ND6_QUEUEING */
131 #define nd6_free_q(q) pbuf_free(q)
132 #endif /* LWIP_ND6_QUEUEING */
133 static void nd6_send_q(s8_t i);
134  
135  
136 /**
137 * A local address has been determined to be a duplicate. Take the appropriate
138 * action(s) on the address and the interface as a whole.
139 *
140 * @param netif the netif that owns the address
141 * @param addr_idx the index of the address detected to be a duplicate
142 */
143 static void
144 nd6_duplicate_addr_detected(struct netif *netif, s8_t addr_idx)
145 {
146  
147 /* Mark the address as duplicate, but leave its lifetimes alone. If this was
148 * a manually assigned address, it will remain in existence as duplicate, and
149 * as such be unusable for any practical purposes until manual intervention.
150 * If this was an autogenerated address, the address will follow normal
151 * expiration rules, and thus disappear once its valid lifetime expires. */
152 netif_ip6_addr_set_state(netif, addr_idx, IP6_ADDR_DUPLICATED);
153  
154 #if LWIP_IPV6_AUTOCONFIG
155 /* If the affected address was the link-local address that we use to generate
156 * all other addresses, then we should not continue to use those derived
157 * addresses either, so mark them as duplicate as well. For autoconfig-only
158 * setups, this will make the interface effectively unusable, approaching the
159 * intention of RFC 4862 Sec. 5.4.5. @todo implement the full requirements */
160 if (addr_idx == 0) {
161 s8_t i;
162 for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
163 if (!ip6_addr_isinvalid(netif_ip6_addr_state(netif, i)) &&
164 !netif_ip6_addr_isstatic(netif, i)) {
165 netif_ip6_addr_set_state(netif, i, IP6_ADDR_DUPLICATED);
166 }
167 }
168 }
169 #endif /* LWIP_IPV6_AUTOCONFIG */
170 }
171  
172 #if LWIP_IPV6_AUTOCONFIG
173 /**
174 * We received a router advertisement that contains a prefix with the
175 * autoconfiguration flag set. Add or update an associated autogenerated
176 * address.
177 *
178 * @param netif the netif on which the router advertisement arrived
179 * @param prefix_opt a pointer to the prefix option data
180 * @param prefix_addr an aligned copy of the prefix address
181 */
182 static void
183 nd6_process_autoconfig_prefix(struct netif *netif,
184 struct prefix_option *prefix_opt, const ip6_addr_t *prefix_addr)
185 {
186 ip6_addr_t ip6addr;
187 u32_t valid_life, pref_life;
188 u8_t addr_state;
189 s8_t i, free_idx;
190  
191 /* The caller already checks RFC 4862 Sec. 5.5.3 points (a) and (b). We do
192 * the rest, starting with checks for (c) and (d) here. */
193 valid_life = lwip_htonl(prefix_opt->valid_lifetime);
194 pref_life = lwip_htonl(prefix_opt->preferred_lifetime);
195 if (pref_life > valid_life || prefix_opt->prefix_length != 64) {
196 return; /* silently ignore this prefix for autoconfiguration purposes */
197 }
198  
199 /* If an autogenerated address already exists for this prefix, update its
200 * lifetimes. An address is considered autogenerated if 1) it is not static
201 * (i.e., manually assigned), and 2) there is an advertised autoconfiguration
202 * prefix for it (the one we are processing here). This does not necessarily
203 * exclude the possibility that the address was actually assigned by, say,
204 * DHCPv6. If that distinction becomes important in the future, more state
205 * must be kept. As explained elsewhere we also update lifetimes of tentative
206 * and duplicate addresses. Skip address slot 0 (the link-local address). */
207 for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
208 addr_state = netif_ip6_addr_state(netif, i);
209 if (!ip6_addr_isinvalid(addr_state) && !netif_ip6_addr_isstatic(netif, i) &&
210 ip6_addr_netcmp(prefix_addr, netif_ip6_addr(netif, i))) {
211 /* Update the valid lifetime, as per RFC 4862 Sec. 5.5.3 point (e).
212 * The valid lifetime will never drop to zero as a result of this. */
213 u32_t remaining_life = netif_ip6_addr_valid_life(netif, i);
214 if (valid_life > ND6_2HRS || valid_life > remaining_life) {
215 netif_ip6_addr_set_valid_life(netif, i, valid_life);
216 } else if (remaining_life > ND6_2HRS) {
217 netif_ip6_addr_set_valid_life(netif, i, ND6_2HRS);
218 }
219 LWIP_ASSERT("bad valid lifetime", !netif_ip6_addr_isstatic(netif, i));
220 /* Update the preferred lifetime. No bounds checks are needed here. In
221 * rare cases the advertisement may un-deprecate the address, though.
222 * Deprecation is left to the timer code where it is handled anyway. */
223 if (pref_life > 0 && addr_state == IP6_ADDR_DEPRECATED) {
224 netif_ip6_addr_set_state(netif, i, IP6_ADDR_PREFERRED);
225 }
226 netif_ip6_addr_set_pref_life(netif, i, pref_life);
227 return; /* there should be at most one matching address */
228 }
229 }
230  
231 /* No autogenerated address exists for this prefix yet. See if we can add a
232 * new one. However, if IPv6 autoconfiguration is administratively disabled,
233 * do not generate new addresses, but do keep updating lifetimes for existing
234 * addresses. Also, when adding new addresses, we must protect explicitly
235 * against a valid lifetime of zero, because again, we use that as a special
236 * value. The generated address would otherwise expire immediately anyway.
237 * Finally, the original link-local address must be usable at all. We start
238 * creating addresses even if the link-local address is still in tentative
239 * state though, and deal with the fallout of that upon DAD collision. */
240 addr_state = netif_ip6_addr_state(netif, 0);
241 if (!netif->ip6_autoconfig_enabled || valid_life == IP6_ADDR_LIFE_STATIC ||
242 ip6_addr_isinvalid(addr_state) || ip6_addr_isduplicated(addr_state)) {
243 return;
244 }
245  
246 /* Construct the new address that we intend to use, and then see if that
247 * address really does not exist. It might have been added manually, after
248 * all. As a side effect, find a free slot. Note that we cannot use
249 * netif_add_ip6_address() here, as it would return ERR_OK if the address
250 * already did exist, resulting in that address being given lifetimes. */
251 IP6_ADDR(&ip6addr, prefix_addr->addr[0], prefix_addr->addr[1],
252 netif_ip6_addr(netif, 0)->addr[2], netif_ip6_addr(netif, 0)->addr[3]);
253 ip6_addr_assign_zone(&ip6addr, IP6_UNICAST, netif);
254  
255 free_idx = 0;
256 for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
257 if (!ip6_addr_isinvalid(netif_ip6_addr_state(netif, i))) {
258 if (ip6_addr_cmp(&ip6addr, netif_ip6_addr(netif, i))) {
259 return; /* formed address already exists */
260 }
261 } else if (free_idx == 0) {
262 free_idx = i;
263 }
264 }
265 if (free_idx == 0) {
266 return; /* no address slots available, try again on next advertisement */
267 }
268  
269 /* Assign the new address to the interface. */
270 ip_addr_copy_from_ip6(netif->ip6_addr[free_idx], ip6addr);
271 netif_ip6_addr_set_valid_life(netif, free_idx, valid_life);
272 netif_ip6_addr_set_pref_life(netif, free_idx, pref_life);
273 netif_ip6_addr_set_state(netif, free_idx, IP6_ADDR_TENTATIVE);
274 }
275 #endif /* LWIP_IPV6_AUTOCONFIG */
276  
277 /**
278 * Process an incoming neighbor discovery message
279 *
280 * @param p the nd packet, p->payload pointing to the icmpv6 header
281 * @param inp the netif on which this packet was received
282 */
283 void
284 nd6_input(struct pbuf *p, struct netif *inp)
285 {
286 u8_t msg_type;
287 s8_t i;
288  
289 ND6_STATS_INC(nd6.recv);
290  
291 msg_type = *((u8_t *)p->payload);
292 switch (msg_type) {
293 case ICMP6_TYPE_NA: /* Neighbor Advertisement. */
294 {
295 struct na_header *na_hdr;
296 struct lladdr_option *lladdr_opt;
297 ip6_addr_t target_address;
298  
299 /* Check that na header fits in packet. */
300 if (p->len < (sizeof(struct na_header))) {
301 /* @todo debug message */
302 pbuf_free(p);
303 ND6_STATS_INC(nd6.lenerr);
304 ND6_STATS_INC(nd6.drop);
305 return;
306 }
307  
308 na_hdr = (struct na_header *)p->payload;
309  
310 /* Create an aligned, zoned copy of the target address. */
311 ip6_addr_copy_from_packed(target_address, na_hdr->target_address);
312 ip6_addr_assign_zone(&target_address, IP6_UNICAST, inp);
313  
314 /* Check a subset of the other RFC 4861 Sec. 7.1.2 requirements. */
315 if (IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || na_hdr->code != 0 ||
316 ip6_addr_ismulticast(&target_address)) {
317 pbuf_free(p);
318 ND6_STATS_INC(nd6.proterr);
319 ND6_STATS_INC(nd6.drop);
320 return;
321 }
322  
323 /* @todo RFC MUST: if IP destination is multicast, Solicited flag is zero */
324 /* @todo RFC MUST: all included options have a length greater than zero */
325  
326 /* Unsolicited NA?*/
327 if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
328 /* This is an unsolicited NA.
329 * link-layer changed?
330 * part of DAD mechanism? */
331  
332 #if LWIP_IPV6_DUP_DETECT_ATTEMPTS
333 /* If the target address matches this netif, it is a DAD response. */
334 for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
335 if (!ip6_addr_isinvalid(netif_ip6_addr_state(inp, i)) &&
336 !ip6_addr_isduplicated(netif_ip6_addr_state(inp, i)) &&
337 ip6_addr_cmp(&target_address, netif_ip6_addr(inp, i))) {
338 /* We are using a duplicate address. */
339 nd6_duplicate_addr_detected(inp, i);
340  
341 pbuf_free(p);
342 return;
343 }
344 }
345 #endif /* LWIP_IPV6_DUP_DETECT_ATTEMPTS */
346  
347 /* Check that link-layer address option also fits in packet. */
348 if (p->len < (sizeof(struct na_header) + 2)) {
349 /* @todo debug message */
350 pbuf_free(p);
351 ND6_STATS_INC(nd6.lenerr);
352 ND6_STATS_INC(nd6.drop);
353 return;
354 }
355  
356 lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct na_header));
357  
358 if (p->len < (sizeof(struct na_header) + (lladdr_opt->length << 3))) {
359 /* @todo debug message */
360 pbuf_free(p);
361 ND6_STATS_INC(nd6.lenerr);
362 ND6_STATS_INC(nd6.drop);
363 return;
364 }
365  
366 /* This is an unsolicited NA, most likely there was a LLADDR change. */
367 i = nd6_find_neighbor_cache_entry(&target_address);
368 if (i >= 0) {
369 if (na_hdr->flags & ND6_FLAG_OVERRIDE) {
370 MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
371 }
372 }
373 } else {
374 /* This is a solicited NA.
375 * neighbor address resolution response?
376 * neighbor unreachability detection response? */
377  
378 /* Find the cache entry corresponding to this na. */
379 i = nd6_find_neighbor_cache_entry(&target_address);
380 if (i < 0) {
381 /* We no longer care about this target address. drop it. */
382 pbuf_free(p);
383 return;
384 }
385  
386 /* Update cache entry. */
387 if ((na_hdr->flags & ND6_FLAG_OVERRIDE) ||
388 (neighbor_cache[i].state == ND6_INCOMPLETE)) {
389 /* Check that link-layer address option also fits in packet. */
390 if (p->len < (sizeof(struct na_header) + 2)) {
391 /* @todo debug message */
392 pbuf_free(p);
393 ND6_STATS_INC(nd6.lenerr);
394 ND6_STATS_INC(nd6.drop);
395 return;
396 }
397  
398 lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct na_header));
399  
400 if (p->len < (sizeof(struct na_header) + (lladdr_opt->length << 3))) {
401 /* @todo debug message */
402 pbuf_free(p);
403 ND6_STATS_INC(nd6.lenerr);
404 ND6_STATS_INC(nd6.drop);
405 return;
406 }
407  
408 MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
409 }
410  
411 neighbor_cache[i].netif = inp;
412 neighbor_cache[i].state = ND6_REACHABLE;
413 neighbor_cache[i].counter.reachable_time = reachable_time;
414  
415 /* Send queued packets, if any. */
416 if (neighbor_cache[i].q != NULL) {
417 nd6_send_q(i);
418 }
419 }
420  
421 break; /* ICMP6_TYPE_NA */
422 }
423 case ICMP6_TYPE_NS: /* Neighbor solicitation. */
424 {
425 struct ns_header *ns_hdr;
426 struct lladdr_option *lladdr_opt;
427 ip6_addr_t target_address;
428 u8_t accepted;
429  
430 /* Check that ns header fits in packet. */
431 if (p->len < sizeof(struct ns_header)) {
432 /* @todo debug message */
433 pbuf_free(p);
434 ND6_STATS_INC(nd6.lenerr);
435 ND6_STATS_INC(nd6.drop);
436 return;
437 }
438  
439 ns_hdr = (struct ns_header *)p->payload;
440  
441 /* Create an aligned, zoned copy of the target address. */
442 ip6_addr_copy_from_packed(target_address, ns_hdr->target_address);
443 ip6_addr_assign_zone(&target_address, IP6_UNICAST, inp);
444  
445 /* Check a subset of the other RFC 4861 Sec. 7.1.1 requirements. */
446 if (IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || ns_hdr->code != 0 ||
447 ip6_addr_ismulticast(&target_address)) {
448 pbuf_free(p);
449 ND6_STATS_INC(nd6.proterr);
450 ND6_STATS_INC(nd6.drop);
451 return;
452 }
453  
454 /* @todo RFC MUST: all included options have a length greater than zero */
455 /* @todo RFC MUST: if IP source is 'any', destination is solicited-node multicast address */
456 /* @todo RFC MUST: if IP source is 'any', there is no source LL address option */
457  
458 /* Check if there is a link-layer address provided. Only point to it if in this buffer. */
459 if (p->len >= (sizeof(struct ns_header) + 2)) {
460 lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct ns_header));
461 if (p->len < (sizeof(struct ns_header) + (lladdr_opt->length << 3))) {
462 lladdr_opt = NULL;
463 }
464 } else {
465 lladdr_opt = NULL;
466 }
467  
468 /* Check if the target address is configured on the receiving netif. */
469 accepted = 0;
470 for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) {
471 if ((ip6_addr_isvalid(netif_ip6_addr_state(inp, i)) ||
472 (ip6_addr_istentative(netif_ip6_addr_state(inp, i)) &&
473 ip6_addr_isany(ip6_current_src_addr()))) &&
474 ip6_addr_cmp(&target_address, netif_ip6_addr(inp, i))) {
475 accepted = 1;
476 break;
477 }
478 }
479  
480 /* NS not for us? */
481 if (!accepted) {
482 pbuf_free(p);
483 return;
484 }
485  
486 /* Check for ANY address in src (DAD algorithm). */
487 if (ip6_addr_isany(ip6_current_src_addr())) {
488 /* Sender is validating this address. */
489 for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) {
490 if (!ip6_addr_isinvalid(netif_ip6_addr_state(inp, i)) &&
491 ip6_addr_cmp(&target_address, netif_ip6_addr(inp, i))) {
492 /* Send a NA back so that the sender does not use this address. */
493 nd6_send_na(inp, netif_ip6_addr(inp, i), ND6_FLAG_OVERRIDE | ND6_SEND_FLAG_ALLNODES_DEST);
494 if (ip6_addr_istentative(netif_ip6_addr_state(inp, i))) {
495 /* We shouldn't use this address either. */
496 nd6_duplicate_addr_detected(inp, i);
497 }
498 }
499 }
500 } else {
501 /* Sender is trying to resolve our address. */
502 /* Verify that they included their own link-layer address. */
503 if (lladdr_opt == NULL) {
504 /* Not a valid message. */
505 pbuf_free(p);
506 ND6_STATS_INC(nd6.proterr);
507 ND6_STATS_INC(nd6.drop);
508 return;
509 }
510  
511 i = nd6_find_neighbor_cache_entry(ip6_current_src_addr());
512 if (i>= 0) {
513 /* We already have a record for the solicitor. */
514 if (neighbor_cache[i].state == ND6_INCOMPLETE) {
515 neighbor_cache[i].netif = inp;
516 MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
517  
518 /* Delay probe in case we get confirmation of reachability from upper layer (TCP). */
519 neighbor_cache[i].state = ND6_DELAY;
520 neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL;
521 }
522 } else {
523 /* Add their IPv6 address and link-layer address to neighbor cache.
524 * We will need it at least to send a unicast NA message, but most
525 * likely we will also be communicating with this node soon. */
526 i = nd6_new_neighbor_cache_entry();
527 if (i < 0) {
528 /* We couldn't assign a cache entry for this neighbor.
529 * we won't be able to reply. drop it. */
530 pbuf_free(p);
531 ND6_STATS_INC(nd6.memerr);
532 return;
533 }
534 neighbor_cache[i].netif = inp;
535 MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
536 ip6_addr_set(&(neighbor_cache[i].next_hop_address), ip6_current_src_addr());
537  
538 /* Receiving a message does not prove reachability: only in one direction.
539 * Delay probe in case we get confirmation of reachability from upper layer (TCP). */
540 neighbor_cache[i].state = ND6_DELAY;
541 neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL;
542 }
543  
544 /* Send back a NA for us. Allocate the reply pbuf. */
545 nd6_send_na(inp, &target_address, ND6_FLAG_SOLICITED | ND6_FLAG_OVERRIDE);
546 }
547  
548 break; /* ICMP6_TYPE_NS */
549 }
550 case ICMP6_TYPE_RA: /* Router Advertisement. */
551 {
552 struct ra_header *ra_hdr;
553 u8_t *buffer; /* Used to copy options. */
554 u16_t offset;
555 #if LWIP_ND6_RDNSS_MAX_DNS_SERVERS
556 /* There can be multiple RDNSS options per RA */
557 u8_t rdnss_server_idx = 0;
558 #endif /* LWIP_ND6_RDNSS_MAX_DNS_SERVERS */
559  
560 /* Check that RA header fits in packet. */
561 if (p->len < sizeof(struct ra_header)) {
562 /* @todo debug message */
563 pbuf_free(p);
564 ND6_STATS_INC(nd6.lenerr);
565 ND6_STATS_INC(nd6.drop);
566 return;
567 }
568  
569 ra_hdr = (struct ra_header *)p->payload;
570  
571 /* Check a subset of the other RFC 4861 Sec. 6.1.2 requirements. */
572 if (!ip6_addr_islinklocal(ip6_current_src_addr()) ||
573 IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || ra_hdr->code != 0) {
574 pbuf_free(p);
575 ND6_STATS_INC(nd6.proterr);
576 ND6_STATS_INC(nd6.drop);
577 return;
578 }
579  
580 /* @todo RFC MUST: all included options have a length greater than zero */
581  
582 /* If we are sending RS messages, stop. */
583 #if LWIP_IPV6_SEND_ROUTER_SOLICIT
584 /* ensure at least one solicitation is sent */
585 if ((inp->rs_count < LWIP_ND6_MAX_MULTICAST_SOLICIT) ||
586 (nd6_send_rs(inp) == ERR_OK)) {
587 inp->rs_count = 0;
588 }
589 #endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
590  
591 /* Get the matching default router entry. */
592 i = nd6_get_router(ip6_current_src_addr(), inp);
593 if (i < 0) {
594 /* Create a new router entry. */
595 i = nd6_new_router(ip6_current_src_addr(), inp);
596 }
597  
598 if (i < 0) {
599 /* Could not create a new router entry. */
600 pbuf_free(p);
601 ND6_STATS_INC(nd6.memerr);
602 return;
603 }
604  
605 /* Re-set invalidation timer. */
606 default_router_list[i].invalidation_timer = lwip_htons(ra_hdr->router_lifetime);
607  
608 /* Re-set default timer values. */
609 #if LWIP_ND6_ALLOW_RA_UPDATES
610 if (ra_hdr->retrans_timer > 0) {
611 retrans_timer = lwip_htonl(ra_hdr->retrans_timer);
612 }
613 if (ra_hdr->reachable_time > 0) {
614 reachable_time = lwip_htonl(ra_hdr->reachable_time);
615 }
616 #endif /* LWIP_ND6_ALLOW_RA_UPDATES */
617  
618 /* @todo set default hop limit... */
619 /* ra_hdr->current_hop_limit;*/
620  
621 /* Update flags in local entry (incl. preference). */
622 default_router_list[i].flags = ra_hdr->flags;
623  
624 /* Offset to options. */
625 offset = sizeof(struct ra_header);
626  
627 /* Process each option. */
628 while ((p->tot_len - offset) >= 2) {
629 u8_t option_type;
630 u16_t option_len;
631 int option_len8 = pbuf_try_get_at(p, offset + 1);
632 if (option_len8 <= 0) {
633 /* read beyond end or zero length */
634 goto lenerr_drop_free_return;
635 }
636 option_len = ((u8_t)option_len8) << 3;
637 if (option_len > p->tot_len - offset) {
638 /* short packet (option does not fit in) */
639 goto lenerr_drop_free_return;
640 }
641 if (p->len == p->tot_len) {
642 /* no need to copy from contiguous pbuf */
643 buffer = &((u8_t*)p->payload)[offset];
644 } else {
645 /* check if this option fits into our buffer */
646 if (option_len > sizeof(nd6_ra_buffer)) {
647 option_type = pbuf_get_at(p, offset);
648 /* invalid option length */
649 if (option_type != ND6_OPTION_TYPE_RDNSS) {
650 goto lenerr_drop_free_return;
651 }
652 /* we allow RDNSS option to be longer - we'll just drop some servers */
653 option_len = sizeof(nd6_ra_buffer);
654 }
655 buffer = (u8_t*)&nd6_ra_buffer;
656 option_len = pbuf_copy_partial(p, &nd6_ra_buffer, option_len, offset);
657 }
658 option_type = buffer[0];
659 switch (option_type) {
660 case ND6_OPTION_TYPE_SOURCE_LLADDR:
661 {
662 struct lladdr_option *lladdr_opt;
663 if (option_len < sizeof(struct lladdr_option)) {
664 goto lenerr_drop_free_return;
665 }
666 lladdr_opt = (struct lladdr_option *)buffer;
667 if ((default_router_list[i].neighbor_entry != NULL) &&
668 (default_router_list[i].neighbor_entry->state == ND6_INCOMPLETE)) {
669 SMEMCPY(default_router_list[i].neighbor_entry->lladdr, lladdr_opt->addr, inp->hwaddr_len);
670 default_router_list[i].neighbor_entry->state = ND6_REACHABLE;
671 default_router_list[i].neighbor_entry->counter.reachable_time = reachable_time;
672 }
673 break;
674 }
675 case ND6_OPTION_TYPE_MTU:
676 {
677 struct mtu_option *mtu_opt;
678 if (option_len < sizeof(struct mtu_option)) {
679 goto lenerr_drop_free_return;
680 }
681 mtu_opt = (struct mtu_option *)buffer;
682 if (lwip_htonl(mtu_opt->mtu) >= 1280) {
683 #if LWIP_ND6_ALLOW_RA_UPDATES
684 inp->mtu = (u16_t)lwip_htonl(mtu_opt->mtu);
685 #endif /* LWIP_ND6_ALLOW_RA_UPDATES */
686 }
687 break;
688 }
689 case ND6_OPTION_TYPE_PREFIX_INFO:
690 {
691 struct prefix_option *prefix_opt;
692 ip6_addr_t prefix_addr;
693 if (option_len < sizeof(struct prefix_option)) {
694 goto lenerr_drop_free_return;
695 }
696  
697 prefix_opt = (struct prefix_option *)buffer;
698  
699 /* Get a memory-aligned copy of the prefix. */
700 ip6_addr_copy_from_packed(prefix_addr, prefix_opt->prefix);
701 ip6_addr_assign_zone(&prefix_addr, IP6_UNICAST, inp);
702  
703 if (!ip6_addr_islinklocal(&prefix_addr)) {
704 if ((prefix_opt->flags & ND6_PREFIX_FLAG_ON_LINK) &&
705 (prefix_opt->prefix_length == 64)) {
706 /* Add to on-link prefix list. */
707 u32_t valid_life;
708 s8_t prefix;
709  
710 valid_life = lwip_htonl(prefix_opt->valid_lifetime);
711  
712 /* find cache entry for this prefix. */
713 prefix = nd6_get_onlink_prefix(&prefix_addr, inp);
714 if (prefix < 0 && valid_life > 0) {
715 /* Create a new cache entry. */
716 prefix = nd6_new_onlink_prefix(&prefix_addr, inp);
717 }
718 if (prefix >= 0) {
719 prefix_list[prefix].invalidation_timer = valid_life;
720 }
721 }
722 #if LWIP_IPV6_AUTOCONFIG
723 if (prefix_opt->flags & ND6_PREFIX_FLAG_AUTONOMOUS) {
724 /* Perform processing for autoconfiguration. */
725 nd6_process_autoconfig_prefix(inp, prefix_opt, &prefix_addr);
726 }
727 #endif /* LWIP_IPV6_AUTOCONFIG */
728 }
729  
730 break;
731 }
732 case ND6_OPTION_TYPE_ROUTE_INFO:
733 /* @todo implement preferred routes.
734 struct route_option * route_opt;
735 route_opt = (struct route_option *)buffer;*/
736  
737 break;
738 #if LWIP_ND6_RDNSS_MAX_DNS_SERVERS
739 case ND6_OPTION_TYPE_RDNSS:
740 {
741 u8_t num, n;
742 u16_t copy_offset = offset + SIZEOF_RDNSS_OPTION_BASE;
743 struct rdnss_option * rdnss_opt;
744 if (option_len < SIZEOF_RDNSS_OPTION_BASE) {
745 goto lenerr_drop_free_return;
746 }
747  
748 rdnss_opt = (struct rdnss_option *)buffer;
749 num = (rdnss_opt->length - 1) / 2;
750 for (n = 0; (rdnss_server_idx < DNS_MAX_SERVERS) && (n < num); n++) {
751 ip_addr_t rdnss_address;
752  
753 /* Copy directly from pbuf to get an aligned, zoned copy of the prefix. */
754 if (pbuf_copy_partial(p, &rdnss_address, sizeof(ip6_addr_p_t), copy_offset) == sizeof(ip6_addr_p_t)) {
755 IP_SET_TYPE_VAL(rdnss_address, IPADDR_TYPE_V6);
756 ip6_addr_assign_zone(ip_2_ip6(&rdnss_address), IP6_UNKNOWN, inp);
757  
758 if (htonl(rdnss_opt->lifetime) > 0) {
759 /* TODO implement Lifetime > 0 */
760 dns_setserver(rdnss_server_idx++, &rdnss_address);
761 } else {
762 /* TODO implement DNS removal in dns.c */
763 u8_t s;
764 for (s = 0; s < DNS_MAX_SERVERS; s++) {
765 const ip_addr_t *addr = dns_getserver(s);
766 if(ip_addr_cmp(addr, &rdnss_address)) {
767 dns_setserver(s, NULL);
768 }
769 }
770 }
771 }
772 }
773 break;
774 }
775 #endif /* LWIP_ND6_RDNSS_MAX_DNS_SERVERS */
776 default:
777 /* Unrecognized option, abort. */
778 ND6_STATS_INC(nd6.proterr);
779 break;
780 }
781 /* option length is checked earlier to be non-zero to make sure loop ends */
782 offset += 8 * (u8_t)option_len8;
783 }
784  
785 break; /* ICMP6_TYPE_RA */
786 }
787 case ICMP6_TYPE_RD: /* Redirect */
788 {
789 struct redirect_header *redir_hdr;
790 struct lladdr_option *lladdr_opt;
791 ip6_addr_t destination_address, target_address;
792  
793 /* Check that Redir header fits in packet. */
794 if (p->len < sizeof(struct redirect_header)) {
795 /* @todo debug message */
796 pbuf_free(p);
797 ND6_STATS_INC(nd6.lenerr);
798 ND6_STATS_INC(nd6.drop);
799 return;
800 }
801  
802 redir_hdr = (struct redirect_header *)p->payload;
803  
804 /* Create an aligned, zoned copy of the destination address. */
805 ip6_addr_copy_from_packed(destination_address, redir_hdr->destination_address);
806 ip6_addr_assign_zone(&destination_address, IP6_UNICAST, inp);
807  
808 /* Check a subset of the other RFC 4861 Sec. 8.1 requirements. */
809 if (!ip6_addr_islinklocal(ip6_current_src_addr()) ||
810 IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM ||
811 redir_hdr->code != 0 || ip6_addr_ismulticast(&destination_address)) {
812 pbuf_free(p);
813 ND6_STATS_INC(nd6.proterr);
814 ND6_STATS_INC(nd6.drop);
815 return;
816 }
817  
818 /* @todo RFC MUST: IP source address equals first-hop router for destination_address */
819 /* @todo RFC MUST: ICMP target address is either link-local address or same as destination_address */
820 /* @todo RFC MUST: all included options have a length greater than zero */
821  
822 if (p->len >= (sizeof(struct redirect_header) + 2)) {
823 lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct redirect_header));
824 if (p->len < (sizeof(struct redirect_header) + (lladdr_opt->length << 3))) {
825 lladdr_opt = NULL;
826 }
827 } else {
828 lladdr_opt = NULL;
829 }
830  
831 /* Find dest address in cache */
832 i = nd6_find_destination_cache_entry(&destination_address);
833 if (i < 0) {
834 /* Destination not in cache, drop packet. */
835 pbuf_free(p);
836 return;
837 }
838  
839 /* Create an aligned, zoned copy of the target address. */
840 ip6_addr_copy_from_packed(target_address, redir_hdr->target_address);
841 ip6_addr_assign_zone(&target_address, IP6_UNICAST, inp);
842  
843 /* Set the new target address. */
844 ip6_addr_copy(destination_cache[i].next_hop_addr, target_address);
845  
846 /* If Link-layer address of other router is given, try to add to neighbor cache. */
847 if (lladdr_opt != NULL) {
848 if (lladdr_opt->type == ND6_OPTION_TYPE_TARGET_LLADDR) {
849 i = nd6_find_neighbor_cache_entry(&target_address);
850 if (i < 0) {
851 i = nd6_new_neighbor_cache_entry();
852 if (i >= 0) {
853 neighbor_cache[i].netif = inp;
854 MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
855 ip6_addr_copy(neighbor_cache[i].next_hop_address, target_address);
856  
857 /* Receiving a message does not prove reachability: only in one direction.
858 * Delay probe in case we get confirmation of reachability from upper layer (TCP). */
859 neighbor_cache[i].state = ND6_DELAY;
860 neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL;
861 }
862 }
863 if (i >= 0) {
864 if (neighbor_cache[i].state == ND6_INCOMPLETE) {
865 MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len);
866 /* Receiving a message does not prove reachability: only in one direction.
867 * Delay probe in case we get confirmation of reachability from upper layer (TCP). */
868 neighbor_cache[i].state = ND6_DELAY;
869 neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL;
870 }
871 }
872 }
873 }
874 break; /* ICMP6_TYPE_RD */
875 }
876 case ICMP6_TYPE_PTB: /* Packet too big */
877 {
878 struct icmp6_hdr *icmp6hdr; /* Packet too big message */
879 struct ip6_hdr *ip6hdr; /* IPv6 header of the packet which caused the error */
880 u32_t pmtu;
881 ip6_addr_t destination_address;
882  
883 /* Check that ICMPv6 header + IPv6 header fit in payload */
884 if (p->len < (sizeof(struct icmp6_hdr) + IP6_HLEN)) {
885 /* drop short packets */
886 pbuf_free(p);
887 ND6_STATS_INC(nd6.lenerr);
888 ND6_STATS_INC(nd6.drop);
889 return;
890 }
891  
892 icmp6hdr = (struct icmp6_hdr *)p->payload;
893 ip6hdr = (struct ip6_hdr *)((u8_t*)p->payload + sizeof(struct icmp6_hdr));
894  
895 /* Create an aligned, zoned copy of the destination address. */
896 ip6_addr_copy_from_packed(destination_address, ip6hdr->dest);
897 ip6_addr_assign_zone(&destination_address, IP6_UNKNOWN, inp);
898  
899 /* Look for entry in destination cache. */
900 i = nd6_find_destination_cache_entry(&destination_address);
901 if (i < 0) {
902 /* Destination not in cache, drop packet. */
903 pbuf_free(p);
904 return;
905 }
906  
907 /* Change the Path MTU. */
908 pmtu = lwip_htonl(icmp6hdr->data);
909 destination_cache[i].pmtu = (u16_t)LWIP_MIN(pmtu, 0xFFFF);
910  
911 break; /* ICMP6_TYPE_PTB */
912 }
913  
914 default:
915 ND6_STATS_INC(nd6.proterr);
916 ND6_STATS_INC(nd6.drop);
917 break; /* default */
918 }
919  
920 pbuf_free(p);
921 return;
922 lenerr_drop_free_return:
923 ND6_STATS_INC(nd6.lenerr);
924 ND6_STATS_INC(nd6.drop);
925 pbuf_free(p);
926 }
927  
928  
929 /**
930 * Periodic timer for Neighbor discovery functions:
931 *
932 * - Update neighbor reachability states
933 * - Update destination cache entries age
934 * - Update invalidation timers of default routers and on-link prefixes
935 * - Update lifetimes of our addresses
936 * - Perform duplicate address detection (DAD) for our addresses
937 * - Send router solicitations
938 */
939 void
940 nd6_tmr(void)
941 {
942 s8_t i;
943 struct netif *netif;
944  
945 /* Process neighbor entries. */
946 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
947 switch (neighbor_cache[i].state) {
948 case ND6_INCOMPLETE:
949 if ((neighbor_cache[i].counter.probes_sent >= LWIP_ND6_MAX_MULTICAST_SOLICIT) &&
950 (!neighbor_cache[i].isrouter)) {
951 /* Retries exceeded. */
952 nd6_free_neighbor_cache_entry(i);
953 } else {
954 /* Send a NS for this entry. */
955 neighbor_cache[i].counter.probes_sent++;
956 nd6_send_neighbor_cache_probe(&neighbor_cache[i], ND6_SEND_FLAG_MULTICAST_DEST);
957 }
958 break;
959 case ND6_REACHABLE:
960 /* Send queued packets, if any are left. Should have been sent already. */
961 if (neighbor_cache[i].q != NULL) {
962 nd6_send_q(i);
963 }
964 if (neighbor_cache[i].counter.reachable_time <= ND6_TMR_INTERVAL) {
965 /* Change to stale state. */
966 neighbor_cache[i].state = ND6_STALE;
967 neighbor_cache[i].counter.stale_time = 0;
968 } else {
969 neighbor_cache[i].counter.reachable_time -= ND6_TMR_INTERVAL;
970 }
971 break;
972 case ND6_STALE:
973 neighbor_cache[i].counter.stale_time++;
974 break;
975 case ND6_DELAY:
976 if (neighbor_cache[i].counter.delay_time <= 1) {
977 /* Change to PROBE state. */
978 neighbor_cache[i].state = ND6_PROBE;
979 neighbor_cache[i].counter.probes_sent = 0;
980 } else {
981 neighbor_cache[i].counter.delay_time--;
982 }
983 break;
984 case ND6_PROBE:
985 if ((neighbor_cache[i].counter.probes_sent >= LWIP_ND6_MAX_MULTICAST_SOLICIT) &&
986 (!neighbor_cache[i].isrouter)) {
987 /* Retries exceeded. */
988 nd6_free_neighbor_cache_entry(i);
989 } else {
990 /* Send a NS for this entry. */
991 neighbor_cache[i].counter.probes_sent++;
992 nd6_send_neighbor_cache_probe(&neighbor_cache[i], 0);
993 }
994 break;
995 case ND6_NO_ENTRY:
996 default:
997 /* Do nothing. */
998 break;
999 }
1000 }
1001  
1002 /* Process destination entries. */
1003 for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
1004 destination_cache[i].age++;
1005 }
1006  
1007 /* Process router entries. */
1008 for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) {
1009 if (default_router_list[i].neighbor_entry != NULL) {
1010 /* Active entry. */
1011 if (default_router_list[i].invalidation_timer <= ND6_TMR_INTERVAL / 1000) {
1012 /* No more than 1 second remaining. Clear this entry. Also clear any of
1013 * its destination cache entries, as per RFC 4861 Sec. 5.3 and 6.3.5. */
1014 s8_t j;
1015 for (j = 0; j < LWIP_ND6_NUM_DESTINATIONS; j++) {
1016 if (ip6_addr_cmp(&destination_cache[j].next_hop_addr,
1017 &default_router_list[i].neighbor_entry->next_hop_address)) {
1018 ip6_addr_set_any(&destination_cache[j].destination_addr);
1019 }
1020 }
1021 default_router_list[i].neighbor_entry->isrouter = 0;
1022 default_router_list[i].neighbor_entry = NULL;
1023 default_router_list[i].invalidation_timer = 0;
1024 default_router_list[i].flags = 0;
1025 } else {
1026 default_router_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000;
1027 }
1028 }
1029 }
1030  
1031 /* Process prefix entries. */
1032 for (i = 0; i < LWIP_ND6_NUM_PREFIXES; i++) {
1033 if (prefix_list[i].netif != NULL) {
1034 if (prefix_list[i].invalidation_timer <= ND6_TMR_INTERVAL / 1000) {
1035 /* Entry timed out, remove it */
1036 prefix_list[i].invalidation_timer = 0;
1037 prefix_list[i].netif = NULL;
1038 } else {
1039 prefix_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000;
1040 }
1041 }
1042 }
1043  
1044 /* Process our own addresses, updating address lifetimes and/or DAD state. */
1045 NETIF_FOREACH(netif) {
1046 for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) {
1047 u8_t addr_state;
1048 #if LWIP_IPV6_ADDRESS_LIFETIMES
1049 /* Step 1: update address lifetimes (valid and preferred). */
1050 addr_state = netif_ip6_addr_state(netif, i);
1051 /* RFC 4862 is not entirely clear as to whether address lifetimes affect
1052 * tentative addresses, and is even less clear as to what should happen
1053 * with duplicate addresses. We choose to track and update lifetimes for
1054 * both those types, although for different reasons:
1055 * - for tentative addresses, the line of thought of Sec. 5.7 combined
1056 * with the potentially long period that an address may be in tentative
1057 * state (due to the interface being down) suggests that lifetimes
1058 * should be independent of external factors which would include DAD;
1059 * - for duplicate addresses, retiring them early could result in a new
1060 * but unwanted attempt at marking them as valid, while retiring them
1061 * late/never could clog up address slots on the netif.
1062 * As a result, we may end up expiring addresses of either type here.
1063 */
1064 if (!ip6_addr_isinvalid(addr_state) &&
1065 !netif_ip6_addr_isstatic(netif, i)) {
1066 u32_t life = netif_ip6_addr_valid_life(netif, i);
1067 if (life <= ND6_TMR_INTERVAL / 1000) {
1068 /* The address has expired. */
1069 netif_ip6_addr_set_valid_life(netif, i, 0);
1070 netif_ip6_addr_set_pref_life(netif, i, 0);
1071 netif_ip6_addr_set_state(netif, i, IP6_ADDR_INVALID);
1072 } else {
1073 if (!ip6_addr_life_isinfinite(life)) {
1074 life -= ND6_TMR_INTERVAL / 1000;
1075 LWIP_ASSERT("bad valid lifetime", life != IP6_ADDR_LIFE_STATIC);
1076 netif_ip6_addr_set_valid_life(netif, i, life);
1077 }
1078 /* The address is still here. Update the preferred lifetime too. */
1079 life = netif_ip6_addr_pref_life(netif, i);
1080 if (life <= ND6_TMR_INTERVAL / 1000) {
1081 /* This case must also trigger if 'life' was already zero, so as to
1082 * deal correctly with advertised preferred-lifetime reductions. */
1083 netif_ip6_addr_set_pref_life(netif, i, 0);
1084 if (addr_state == IP6_ADDR_PREFERRED)
1085 netif_ip6_addr_set_state(netif, i, IP6_ADDR_DEPRECATED);
1086 } else if (!ip6_addr_life_isinfinite(life)) {
1087 life -= ND6_TMR_INTERVAL / 1000;
1088 netif_ip6_addr_set_pref_life(netif, i, life);
1089 }
1090 }
1091 }
1092 /* The address state may now have changed, so reobtain it next. */
1093 #endif /* LWIP_IPV6_ADDRESS_LIFETIMES */
1094 /* Step 2: update DAD state. */
1095 addr_state = netif_ip6_addr_state(netif, i);
1096 if (ip6_addr_istentative(addr_state)) {
1097 if ((addr_state & IP6_ADDR_TENTATIVE_COUNT_MASK) >= LWIP_IPV6_DUP_DETECT_ATTEMPTS) {
1098 /* No NA received in response. Mark address as valid. For dynamic
1099 * addresses with an expired preferred lifetime, the state is set to
1100 * deprecated right away. That should almost never happen, though. */
1101 addr_state = IP6_ADDR_PREFERRED;
1102 #if LWIP_IPV6_ADDRESS_LIFETIMES
1103 if (!netif_ip6_addr_isstatic(netif, i) &&
1104 netif_ip6_addr_pref_life(netif, i) == 0) {
1105 addr_state = IP6_ADDR_DEPRECATED;
1106 }
1107 #endif /* LWIP_IPV6_ADDRESS_LIFETIMES */
1108 netif_ip6_addr_set_state(netif, i, addr_state);
1109 } else if (netif_is_up(netif) && netif_is_link_up(netif)) {
1110 /* tentative: set next state by increasing by one */
1111 netif_ip6_addr_set_state(netif, i, addr_state + 1);
1112 /* Send a NS for this address. Use the unspecified address as source
1113 * address in all cases (RFC 4862 Sec. 5.4.2), not in the least
1114 * because as it is, we only consider multicast replies for DAD. */
1115 nd6_send_ns(netif, netif_ip6_addr(netif, i),
1116 ND6_SEND_FLAG_MULTICAST_DEST | ND6_SEND_FLAG_ANY_SRC);
1117 }
1118 }
1119 }
1120 }
1121  
1122 #if LWIP_IPV6_SEND_ROUTER_SOLICIT
1123 /* Send router solicitation messages, if necessary. */
1124 NETIF_FOREACH(netif) {
1125 if ((netif->rs_count > 0) && netif_is_up(netif) &&
1126 netif_is_link_up(netif) &&
1127 !ip6_addr_isinvalid(netif_ip6_addr_state(netif, 0)) &&
1128 !ip6_addr_isduplicated(netif_ip6_addr_state(netif, 0))) {
1129 if (nd6_send_rs(netif) == ERR_OK) {
1130 netif->rs_count--;
1131 }
1132 }
1133 }
1134 #endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
1135  
1136 }
1137  
1138 /** Send a neighbor solicitation message for a specific neighbor cache entry
1139 *
1140 * @param entry the neightbor cache entry for wich to send the message
1141 * @param flags one of ND6_SEND_FLAG_*
1142 */
1143 static void
1144 nd6_send_neighbor_cache_probe(struct nd6_neighbor_cache_entry *entry, u8_t flags)
1145 {
1146 nd6_send_ns(entry->netif, &entry->next_hop_address, flags);
1147 }
1148  
1149 /**
1150 * Send a neighbor solicitation message
1151 *
1152 * @param netif the netif on which to send the message
1153 * @param target_addr the IPv6 target address for the ND message
1154 * @param flags one of ND6_SEND_FLAG_*
1155 */
1156 static void
1157 nd6_send_ns(struct netif *netif, const ip6_addr_t *target_addr, u8_t flags)
1158 {
1159 struct ns_header *ns_hdr;
1160 struct pbuf *p;
1161 const ip6_addr_t *src_addr;
1162 u16_t lladdr_opt_len;
1163  
1164 LWIP_ASSERT("target address is required", target_addr != NULL);
1165  
1166 if (!(flags & ND6_SEND_FLAG_ANY_SRC) &&
1167 ip6_addr_isvalid(netif_ip6_addr_state(netif,0))) {
1168 /* Use link-local address as source address. */
1169 src_addr = netif_ip6_addr(netif, 0);
1170 /* calculate option length (in 8-byte-blocks) */
1171 lladdr_opt_len = ((netif->hwaddr_len + 2) + 7) >> 3;
1172 } else {
1173 src_addr = IP6_ADDR_ANY6;
1174 /* Option "MUST NOT be included when the source IP address is the unspecified address." */
1175 lladdr_opt_len = 0;
1176 }
1177  
1178 /* Allocate a packet. */
1179 p = pbuf_alloc(PBUF_IP, sizeof(struct ns_header) + (lladdr_opt_len << 3), PBUF_RAM);
1180 if (p == NULL) {
1181 ND6_STATS_INC(nd6.memerr);
1182 return;
1183 }
1184  
1185 /* Set fields. */
1186 ns_hdr = (struct ns_header *)p->payload;
1187  
1188 ns_hdr->type = ICMP6_TYPE_NS;
1189 ns_hdr->code = 0;
1190 ns_hdr->chksum = 0;
1191 ns_hdr->reserved = 0;
1192 ip6_addr_copy_to_packed(ns_hdr->target_address, *target_addr);
1193  
1194 if (lladdr_opt_len != 0) {
1195 struct lladdr_option *lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct ns_header));
1196 lladdr_opt->type = ND6_OPTION_TYPE_SOURCE_LLADDR;
1197 lladdr_opt->length = (u8_t)lladdr_opt_len;
1198 SMEMCPY(lladdr_opt->addr, netif->hwaddr, netif->hwaddr_len);
1199 }
1200  
1201 /* Generate the solicited node address for the target address. */
1202 if (flags & ND6_SEND_FLAG_MULTICAST_DEST) {
1203 ip6_addr_set_solicitednode(&multicast_address, target_addr->addr[3]);
1204 ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
1205 target_addr = &multicast_address;
1206 }
1207  
1208 #if CHECKSUM_GEN_ICMP6
1209 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
1210 ns_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len, src_addr,
1211 target_addr);
1212 }
1213 #endif /* CHECKSUM_GEN_ICMP6 */
1214  
1215 /* Send the packet out. */
1216 ND6_STATS_INC(nd6.xmit);
1217 ip6_output_if(p, (src_addr == IP6_ADDR_ANY6) ? NULL : src_addr, target_addr,
1218 ND6_HOPLIM, 0, IP6_NEXTH_ICMP6, netif);
1219 pbuf_free(p);
1220 }
1221  
1222 /**
1223 * Send a neighbor advertisement message
1224 *
1225 * @param netif the netif on which to send the message
1226 * @param target_addr the IPv6 target address for the ND message
1227 * @param flags one of ND6_SEND_FLAG_*
1228 */
1229 static void
1230 nd6_send_na(struct netif *netif, const ip6_addr_t *target_addr, u8_t flags)
1231 {
1232 struct na_header *na_hdr;
1233 struct lladdr_option *lladdr_opt;
1234 struct pbuf *p;
1235 const ip6_addr_t *src_addr;
1236 const ip6_addr_t *dest_addr;
1237 u16_t lladdr_opt_len;
1238  
1239 LWIP_ASSERT("target address is required", target_addr != NULL);
1240  
1241 /* Use link-local address as source address. */
1242 /* src_addr = netif_ip6_addr(netif, 0); */
1243 /* Use target address as source address. */
1244 src_addr = target_addr;
1245  
1246 /* Allocate a packet. */
1247 lladdr_opt_len = ((netif->hwaddr_len + 2) >> 3) + (((netif->hwaddr_len + 2) & 0x07) ? 1 : 0);
1248 p = pbuf_alloc(PBUF_IP, sizeof(struct na_header) + (lladdr_opt_len << 3), PBUF_RAM);
1249 if (p == NULL) {
1250 ND6_STATS_INC(nd6.memerr);
1251 return;
1252 }
1253  
1254 /* Set fields. */
1255 na_hdr = (struct na_header *)p->payload;
1256 lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct na_header));
1257  
1258 na_hdr->type = ICMP6_TYPE_NA;
1259 na_hdr->code = 0;
1260 na_hdr->chksum = 0;
1261 na_hdr->flags = flags & 0xf0;
1262 na_hdr->reserved[0] = 0;
1263 na_hdr->reserved[1] = 0;
1264 na_hdr->reserved[2] = 0;
1265 ip6_addr_copy_to_packed(na_hdr->target_address, *target_addr);
1266  
1267 lladdr_opt->type = ND6_OPTION_TYPE_TARGET_LLADDR;
1268 lladdr_opt->length = (u8_t)lladdr_opt_len;
1269 SMEMCPY(lladdr_opt->addr, netif->hwaddr, netif->hwaddr_len);
1270  
1271 /* Generate the solicited node address for the target address. */
1272 if (flags & ND6_SEND_FLAG_MULTICAST_DEST) {
1273 ip6_addr_set_solicitednode(&multicast_address, target_addr->addr[3]);
1274 ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
1275 dest_addr = &multicast_address;
1276 } else if (flags & ND6_SEND_FLAG_ALLNODES_DEST) {
1277 ip6_addr_set_allnodes_linklocal(&multicast_address);
1278 ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
1279 dest_addr = &multicast_address;
1280 } else {
1281 dest_addr = ip6_current_src_addr();
1282 }
1283  
1284 #if CHECKSUM_GEN_ICMP6
1285 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
1286 na_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len, src_addr,
1287 dest_addr);
1288 }
1289 #endif /* CHECKSUM_GEN_ICMP6 */
1290  
1291 /* Send the packet out. */
1292 ND6_STATS_INC(nd6.xmit);
1293 ip6_output_if(p, src_addr, dest_addr,
1294 ND6_HOPLIM, 0, IP6_NEXTH_ICMP6, netif);
1295 pbuf_free(p);
1296 }
1297  
1298 #if LWIP_IPV6_SEND_ROUTER_SOLICIT
1299 /**
1300 * Send a router solicitation message
1301 *
1302 * @param netif the netif on which to send the message
1303 */
1304 static err_t
1305 nd6_send_rs(struct netif *netif)
1306 {
1307 struct rs_header *rs_hdr;
1308 struct lladdr_option *lladdr_opt;
1309 struct pbuf *p;
1310 const ip6_addr_t *src_addr;
1311 err_t err;
1312 u16_t lladdr_opt_len = 0;
1313  
1314 /* Link-local source address, or unspecified address? */
1315 if (ip6_addr_isvalid(netif_ip6_addr_state(netif, 0))) {
1316 src_addr = netif_ip6_addr(netif, 0);
1317 } else {
1318 src_addr = IP6_ADDR_ANY6;
1319 }
1320  
1321 /* Generate the all routers target address. */
1322 ip6_addr_set_allrouters_linklocal(&multicast_address);
1323 ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
1324  
1325 /* Allocate a packet. */
1326 if (src_addr != IP6_ADDR_ANY6) {
1327 lladdr_opt_len = ((netif->hwaddr_len + 2) >> 3) + (((netif->hwaddr_len + 2) & 0x07) ? 1 : 0);
1328 }
1329 p = pbuf_alloc(PBUF_IP, sizeof(struct rs_header) + (lladdr_opt_len << 3), PBUF_RAM);
1330 if (p == NULL) {
1331 ND6_STATS_INC(nd6.memerr);
1332 return ERR_BUF;
1333 }
1334  
1335 /* Set fields. */
1336 rs_hdr = (struct rs_header *)p->payload;
1337  
1338 rs_hdr->type = ICMP6_TYPE_RS;
1339 rs_hdr->code = 0;
1340 rs_hdr->chksum = 0;
1341 rs_hdr->reserved = 0;
1342  
1343 if (src_addr != IP6_ADDR_ANY6) {
1344 /* Include our hw address. */
1345 lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct rs_header));
1346 lladdr_opt->type = ND6_OPTION_TYPE_SOURCE_LLADDR;
1347 lladdr_opt->length = (u8_t)lladdr_opt_len;
1348 SMEMCPY(lladdr_opt->addr, netif->hwaddr, netif->hwaddr_len);
1349 }
1350  
1351 #if CHECKSUM_GEN_ICMP6
1352 IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
1353 rs_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len, src_addr,
1354 &multicast_address);
1355 }
1356 #endif /* CHECKSUM_GEN_ICMP6 */
1357  
1358 /* Send the packet out. */
1359 ND6_STATS_INC(nd6.xmit);
1360  
1361 err = ip6_output_if(p, (src_addr == IP6_ADDR_ANY6) ? NULL : src_addr, &multicast_address,
1362 ND6_HOPLIM, 0, IP6_NEXTH_ICMP6, netif);
1363 pbuf_free(p);
1364  
1365 return err;
1366 }
1367 #endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */
1368  
1369 /**
1370 * Search for a neighbor cache entry
1371 *
1372 * @param ip6addr the IPv6 address of the neighbor
1373 * @return The neighbor cache entry index that matched, -1 if no
1374 * entry is found
1375 */
1376 static s8_t
1377 nd6_find_neighbor_cache_entry(const ip6_addr_t *ip6addr)
1378 {
1379 s8_t i;
1380 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
1381 if (ip6_addr_cmp(ip6addr, &(neighbor_cache[i].next_hop_address))) {
1382 return i;
1383 }
1384 }
1385 return -1;
1386 }
1387  
1388 /**
1389 * Create a new neighbor cache entry.
1390 *
1391 * If no unused entry is found, will try to recycle an old entry
1392 * according to ad-hoc "age" heuristic.
1393 *
1394 * @return The neighbor cache entry index that was created, -1 if no
1395 * entry could be created
1396 */
1397 static s8_t
1398 nd6_new_neighbor_cache_entry(void)
1399 {
1400 s8_t i;
1401 s8_t j;
1402 u32_t time;
1403  
1404  
1405 /* First, try to find an empty entry. */
1406 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
1407 if (neighbor_cache[i].state == ND6_NO_ENTRY) {
1408 return i;
1409 }
1410 }
1411  
1412 /* We need to recycle an entry. in general, do not recycle if it is a router. */
1413  
1414 /* Next, try to find a Stale entry. */
1415 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
1416 if ((neighbor_cache[i].state == ND6_STALE) &&
1417 (!neighbor_cache[i].isrouter)) {
1418 nd6_free_neighbor_cache_entry(i);
1419 return i;
1420 }
1421 }
1422  
1423 /* Next, try to find a Probe entry. */
1424 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
1425 if ((neighbor_cache[i].state == ND6_PROBE) &&
1426 (!neighbor_cache[i].isrouter)) {
1427 nd6_free_neighbor_cache_entry(i);
1428 return i;
1429 }
1430 }
1431  
1432 /* Next, try to find a Delayed entry. */
1433 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
1434 if ((neighbor_cache[i].state == ND6_DELAY) &&
1435 (!neighbor_cache[i].isrouter)) {
1436 nd6_free_neighbor_cache_entry(i);
1437 return i;
1438 }
1439 }
1440  
1441 /* Next, try to find the oldest reachable entry. */
1442 time = 0xfffffffful;
1443 j = -1;
1444 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
1445 if ((neighbor_cache[i].state == ND6_REACHABLE) &&
1446 (!neighbor_cache[i].isrouter)) {
1447 if (neighbor_cache[i].counter.reachable_time < time) {
1448 j = i;
1449 time = neighbor_cache[i].counter.reachable_time;
1450 }
1451 }
1452 }
1453 if (j >= 0) {
1454 nd6_free_neighbor_cache_entry(j);
1455 return j;
1456 }
1457  
1458 /* Next, find oldest incomplete entry without queued packets. */
1459 time = 0;
1460 j = -1;
1461 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
1462 if (
1463 (neighbor_cache[i].q == NULL) &&
1464 (neighbor_cache[i].state == ND6_INCOMPLETE) &&
1465 (!neighbor_cache[i].isrouter)) {
1466 if (neighbor_cache[i].counter.probes_sent >= time) {
1467 j = i;
1468 time = neighbor_cache[i].counter.probes_sent;
1469 }
1470 }
1471 }
1472 if (j >= 0) {
1473 nd6_free_neighbor_cache_entry(j);
1474 return j;
1475 }
1476  
1477 /* Next, find oldest incomplete entry with queued packets. */
1478 time = 0;
1479 j = -1;
1480 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
1481 if ((neighbor_cache[i].state == ND6_INCOMPLETE) &&
1482 (!neighbor_cache[i].isrouter)) {
1483 if (neighbor_cache[i].counter.probes_sent >= time) {
1484 j = i;
1485 time = neighbor_cache[i].counter.probes_sent;
1486 }
1487 }
1488 }
1489 if (j >= 0) {
1490 nd6_free_neighbor_cache_entry(j);
1491 return j;
1492 }
1493  
1494 /* No more entries to try. */
1495 return -1;
1496 }
1497  
1498 /**
1499 * Will free any resources associated with a neighbor cache
1500 * entry, and will mark it as unused.
1501 *
1502 * @param i the neighbor cache entry index to free
1503 */
1504 static void
1505 nd6_free_neighbor_cache_entry(s8_t i)
1506 {
1507 if ((i < 0) || (i >= LWIP_ND6_NUM_NEIGHBORS)) {
1508 return;
1509 }
1510 if (neighbor_cache[i].isrouter) {
1511 /* isrouter needs to be cleared before deleting a neighbor cache entry */
1512 return;
1513 }
1514  
1515 /* Free any queued packets. */
1516 if (neighbor_cache[i].q != NULL) {
1517 nd6_free_q(neighbor_cache[i].q);
1518 neighbor_cache[i].q = NULL;
1519 }
1520  
1521 neighbor_cache[i].state = ND6_NO_ENTRY;
1522 neighbor_cache[i].isrouter = 0;
1523 neighbor_cache[i].netif = NULL;
1524 neighbor_cache[i].counter.reachable_time = 0;
1525 ip6_addr_set_zero(&(neighbor_cache[i].next_hop_address));
1526 }
1527  
1528 /**
1529 * Search for a destination cache entry
1530 *
1531 * @param ip6addr the IPv6 address of the destination
1532 * @return The destination cache entry index that matched, -1 if no
1533 * entry is found
1534 */
1535 static s8_t
1536 nd6_find_destination_cache_entry(const ip6_addr_t *ip6addr)
1537 {
1538 s8_t i;
1539  
1540 IP6_ADDR_ZONECHECK(ip6addr);
1541  
1542 for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
1543 if (ip6_addr_cmp(ip6addr, &(destination_cache[i].destination_addr))) {
1544 return i;
1545 }
1546 }
1547 return -1;
1548 }
1549  
1550 /**
1551 * Create a new destination cache entry. If no unused entry is found,
1552 * will recycle oldest entry.
1553 *
1554 * @return The destination cache entry index that was created, -1 if no
1555 * entry was created
1556 */
1557 static s8_t
1558 nd6_new_destination_cache_entry(void)
1559 {
1560 s8_t i, j;
1561 u32_t age;
1562  
1563 /* Find an empty entry. */
1564 for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
1565 if (ip6_addr_isany(&(destination_cache[i].destination_addr))) {
1566 return i;
1567 }
1568 }
1569  
1570 /* Find oldest entry. */
1571 age = 0;
1572 j = LWIP_ND6_NUM_DESTINATIONS - 1;
1573 for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
1574 if (destination_cache[i].age > age) {
1575 j = i;
1576 }
1577 }
1578  
1579 return j;
1580 }
1581  
1582 /**
1583 * Clear the destination cache.
1584 *
1585 * This operation may be necessary for consistency in the light of changing
1586 * local addresses and/or use of the gateway hook.
1587 */
1588 void
1589 nd6_clear_destination_cache(void)
1590 {
1591 int i;
1592  
1593 for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) {
1594 ip6_addr_set_any(&destination_cache[i].destination_addr);
1595 }
1596 }
1597  
1598 /**
1599 * Determine whether an address matches an on-link prefix or the subnet of a
1600 * statically assigned address.
1601 *
1602 * @param ip6addr the IPv6 address to match
1603 * @return 1 if the address is on-link, 0 otherwise
1604 */
1605 static s8_t
1606 nd6_is_prefix_in_netif(const ip6_addr_t *ip6addr, struct netif *netif)
1607 {
1608 s8_t i;
1609  
1610 /* Check to see if the address matches an on-link prefix. */
1611 for (i = 0; i < LWIP_ND6_NUM_PREFIXES; i++) {
1612 if ((prefix_list[i].netif == netif) &&
1613 (prefix_list[i].invalidation_timer > 0) &&
1614 ip6_addr_netcmp(ip6addr, &(prefix_list[i].prefix))) {
1615 return 1;
1616 }
1617 }
1618 /* Check to see if address prefix matches a manually configured (= static)
1619 * address. Static addresses have an implied /64 subnet assignment. Dynamic
1620 * addresses (from autoconfiguration) have no implied subnet assignment, and
1621 * are thus effectively /128 assignments. See RFC 5942 for more on this. */
1622 for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
1623 if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
1624 netif_ip6_addr_isstatic(netif, i) &&
1625 ip6_addr_netcmp(ip6addr, netif_ip6_addr(netif, i))) {
1626 return 1;
1627 }
1628 }
1629 return 0;
1630 }
1631  
1632 /**
1633 * Select a default router for a destination.
1634 *
1635 * This function is used both for routing and for finding a next-hop target for
1636 * a packet. In the former case, the given netif is NULL, and the returned
1637 * router entry must be for a netif suitable for sending packets (up, link up).
1638 * In the latter case, the given netif is not NULL and restricts router choice.
1639 *
1640 * @param ip6addr the destination address
1641 * @param netif the netif for the outgoing packet, if known
1642 * @return the default router entry index, or -1 if no suitable
1643 * router is found
1644 */
1645 static s8_t
1646 nd6_select_router(const ip6_addr_t *ip6addr, struct netif *netif)
1647 {
1648 struct netif *router_netif;
1649 s8_t i, j, valid_router;
1650 static s8_t last_router;
1651  
1652 LWIP_UNUSED_ARG(ip6addr); /* @todo match preferred routes!! (must implement ND6_OPTION_TYPE_ROUTE_INFO) */
1653  
1654 /* @todo: implement default router preference */
1655  
1656 /* Look for valid routers. A reachable router is preferred. */
1657 valid_router = -1;
1658 for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) {
1659 /* Is the router netif both set and apppropriate? */
1660 if (default_router_list[i].neighbor_entry != NULL) {
1661 router_netif = default_router_list[i].neighbor_entry->netif;
1662 if ((router_netif != NULL) && (netif != NULL ? netif == router_netif :
1663 (netif_is_up(router_netif) && netif_is_link_up(router_netif)))) {
1664 /* Is the router valid, i.e., reachable or probably reachable as per
1665 * RFC 4861 Sec. 6.3.6? Note that we will never return a router that
1666 * has no neighbor cache entry, due to the netif association tests. */
1667 if (default_router_list[i].neighbor_entry->state != ND6_INCOMPLETE) {
1668 /* Is the router known to be reachable? */
1669 if (default_router_list[i].neighbor_entry->state == ND6_REACHABLE) {
1670 return i; /* valid and reachable - done! */
1671 } else if (valid_router < 0) {
1672 valid_router = i; /* valid but not known to be reachable */
1673 }
1674 }
1675 }
1676 }
1677 }
1678 if (valid_router >= 0) {
1679 return valid_router;
1680 }
1681  
1682 /* Look for any router for which we have any information at all. */
1683 /* last_router is used for round-robin selection of incomplete routers, as
1684 * recommended in RFC 4861 Sec. 6.3.6 point (2). Advance only when picking a
1685 * route, to select the same router as next-hop target in the common case. */
1686 if ((netif == NULL) && (++last_router >= LWIP_ND6_NUM_ROUTERS)) {
1687 last_router = 0;
1688 }
1689 i = last_router;
1690 for (j = 0; j < LWIP_ND6_NUM_ROUTERS; j++) {
1691 if (default_router_list[i].neighbor_entry != NULL) {
1692 router_netif = default_router_list[i].neighbor_entry->netif;
1693 if ((router_netif != NULL) && (netif != NULL ? netif == router_netif :
1694 (netif_is_up(router_netif) && netif_is_link_up(router_netif)))) {
1695 return i;
1696 }
1697 }
1698 if (++i >= LWIP_ND6_NUM_ROUTERS) {
1699 i = 0;
1700 }
1701 }
1702  
1703 /* no suitable router found. */
1704 return -1;
1705 }
1706  
1707 /**
1708 * Find a router-announced route to the given destination. This route may be
1709 * based on an on-link prefix or a default router.
1710 *
1711 * If a suitable route is found, the returned netif is guaranteed to be in a
1712 * suitable state (up, link up) to be used for packet transmission.
1713 *
1714 * @param ip6addr the destination IPv6 address
1715 * @return the netif to use for the destination, or NULL if none found
1716 */
1717 struct netif *
1718 nd6_find_route(const ip6_addr_t *ip6addr)
1719 {
1720 struct netif *netif;
1721 s8_t i;
1722  
1723 /* @todo decide if it makes sense to check the destination cache first */
1724  
1725 /* Check if there is a matching on-link prefix. There may be multiple
1726 * matches. Pick the first one that is associated with a suitable netif. */
1727 for (i = 0; i < LWIP_ND6_NUM_PREFIXES; ++i) {
1728 netif = prefix_list[i].netif;
1729 if ((netif != NULL) && ip6_addr_netcmp(&prefix_list[i].prefix, ip6addr) &&
1730 netif_is_up(netif) && netif_is_link_up(netif)) {
1731 return netif;
1732 }
1733 }
1734  
1735 /* No on-link prefix match. Find a router that can forward the packet. */
1736 i = nd6_select_router(ip6addr, NULL);
1737 if (i >= 0) {
1738 LWIP_ASSERT("selected router must have a neighbor entry",
1739 default_router_list[i].neighbor_entry != NULL);
1740 return default_router_list[i].neighbor_entry->netif;
1741 }
1742  
1743 return NULL;
1744 }
1745  
1746 /**
1747 * Find an entry for a default router.
1748 *
1749 * @param router_addr the IPv6 address of the router
1750 * @param netif the netif on which the router is found, if known
1751 * @return the index of the router entry, or -1 if not found
1752 */
1753 static s8_t
1754 nd6_get_router(const ip6_addr_t *router_addr, struct netif *netif)
1755 {
1756 s8_t i;
1757  
1758 IP6_ADDR_ZONECHECK_NETIF(router_addr, netif);
1759  
1760 /* Look for router. */
1761 for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) {
1762 if ((default_router_list[i].neighbor_entry != NULL) &&
1763 ((netif != NULL) ? netif == default_router_list[i].neighbor_entry->netif : 1) &&
1764 ip6_addr_cmp(router_addr, &(default_router_list[i].neighbor_entry->next_hop_address))) {
1765 return i;
1766 }
1767 }
1768  
1769 /* router not found. */
1770 return -1;
1771 }
1772  
1773 /**
1774 * Create a new entry for a default router.
1775 *
1776 * @param router_addr the IPv6 address of the router
1777 * @param netif the netif on which the router is connected, if known
1778 * @return the index on the router table, or -1 if could not be created
1779 */
1780 static s8_t
1781 nd6_new_router(const ip6_addr_t *router_addr, struct netif *netif)
1782 {
1783 s8_t router_index;
1784 s8_t free_router_index;
1785 s8_t neighbor_index;
1786  
1787 IP6_ADDR_ZONECHECK_NETIF(router_addr, netif);
1788  
1789 /* Do we have a neighbor entry for this router? */
1790 neighbor_index = nd6_find_neighbor_cache_entry(router_addr);
1791 if (neighbor_index < 0) {
1792 /* Create a neighbor entry for this router. */
1793 neighbor_index = nd6_new_neighbor_cache_entry();
1794 if (neighbor_index < 0) {
1795 /* Could not create neighbor entry for this router. */
1796 return -1;
1797 }
1798 ip6_addr_set(&(neighbor_cache[neighbor_index].next_hop_address), router_addr);
1799 neighbor_cache[neighbor_index].netif = netif;
1800 neighbor_cache[neighbor_index].q = NULL;
1801 neighbor_cache[neighbor_index].state = ND6_INCOMPLETE;
1802 neighbor_cache[neighbor_index].counter.probes_sent = 1;
1803 nd6_send_neighbor_cache_probe(&neighbor_cache[neighbor_index], ND6_SEND_FLAG_MULTICAST_DEST);
1804 }
1805  
1806 /* Mark neighbor as router. */
1807 neighbor_cache[neighbor_index].isrouter = 1;
1808  
1809 /* Look for empty entry. */
1810 free_router_index = LWIP_ND6_NUM_ROUTERS;
1811 for (router_index = LWIP_ND6_NUM_ROUTERS - 1; router_index >= 0; router_index--) {
1812 /* check if router already exists (this is a special case for 2 netifs on the same subnet
1813 - e.g. wifi and cable) */
1814 if(default_router_list[router_index].neighbor_entry == &(neighbor_cache[neighbor_index])){
1815 return router_index;
1816 }
1817 if (default_router_list[router_index].neighbor_entry == NULL) {
1818 /* remember lowest free index to create a new entry */
1819 free_router_index = router_index;
1820 }
1821 }
1822 if (free_router_index < LWIP_ND6_NUM_ROUTERS) {
1823 default_router_list[free_router_index].neighbor_entry = &(neighbor_cache[neighbor_index]);
1824 return free_router_index;
1825 }
1826  
1827 /* Could not create a router entry. */
1828  
1829 /* Mark neighbor entry as not-router. Entry might be useful as neighbor still. */
1830 neighbor_cache[neighbor_index].isrouter = 0;
1831  
1832 /* router not found. */
1833 return -1;
1834 }
1835  
1836 /**
1837 * Find the cached entry for an on-link prefix.
1838 *
1839 * @param prefix the IPv6 prefix that is on-link
1840 * @param netif the netif on which the prefix is on-link
1841 * @return the index on the prefix table, or -1 if not found
1842 */
1843 static s8_t
1844 nd6_get_onlink_prefix(const ip6_addr_t *prefix, struct netif *netif)
1845 {
1846 s8_t i;
1847  
1848 /* Look for prefix in list. */
1849 for (i = 0; i < LWIP_ND6_NUM_PREFIXES; ++i) {
1850 if ((ip6_addr_netcmp(&(prefix_list[i].prefix), prefix)) &&
1851 (prefix_list[i].netif == netif)) {
1852 return i;
1853 }
1854 }
1855  
1856 /* Entry not available. */
1857 return -1;
1858 }
1859  
1860 /**
1861 * Creates a new entry for an on-link prefix.
1862 *
1863 * @param prefix the IPv6 prefix that is on-link
1864 * @param netif the netif on which the prefix is on-link
1865 * @return the index on the prefix table, or -1 if not created
1866 */
1867 static s8_t
1868 nd6_new_onlink_prefix(const ip6_addr_t *prefix, struct netif *netif)
1869 {
1870 s8_t i;
1871  
1872 /* Create new entry. */
1873 for (i = 0; i < LWIP_ND6_NUM_PREFIXES; ++i) {
1874 if ((prefix_list[i].netif == NULL) ||
1875 (prefix_list[i].invalidation_timer == 0)) {
1876 /* Found empty prefix entry. */
1877 prefix_list[i].netif = netif;
1878 ip6_addr_set(&(prefix_list[i].prefix), prefix);
1879 return i;
1880 }
1881 }
1882  
1883 /* Entry not available. */
1884 return -1;
1885 }
1886  
1887 /**
1888 * Determine the next hop for a destination. Will determine if the
1889 * destination is on-link, else a suitable on-link router is selected.
1890 *
1891 * The last entry index is cached for fast entry search.
1892 *
1893 * @param ip6addr the destination address
1894 * @param netif the netif on which the packet will be sent
1895 * @return the neighbor cache entry for the next hop, ERR_RTE if no
1896 * suitable next hop was found, ERR_MEM if no cache entry
1897 * could be created
1898 */
1899 static s8_t
1900 nd6_get_next_hop_entry(const ip6_addr_t *ip6addr, struct netif *netif)
1901 {
1902 #ifdef LWIP_HOOK_ND6_GET_GW
1903 const ip6_addr_t *next_hop_addr;
1904 #endif /* LWIP_HOOK_ND6_GET_GW */
1905 s8_t i;
1906  
1907 IP6_ADDR_ZONECHECK_NETIF(ip6addr, netif);
1908  
1909 #if LWIP_NETIF_HWADDRHINT
1910 if (netif->hints != NULL) {
1911 /* per-pcb cached entry was given */
1912 u8_t addr_hint = netif->hints->addr_hint;
1913 if (addr_hint < LWIP_ND6_NUM_DESTINATIONS) {
1914 nd6_cached_destination_index = addr_hint;
1915 }
1916 }
1917 #endif /* LWIP_NETIF_HWADDRHINT */
1918  
1919 /* Look for ip6addr in destination cache. */
1920 if (ip6_addr_cmp(ip6addr, &(destination_cache[nd6_cached_destination_index].destination_addr))) {
1921 /* the cached entry index is the right one! */
1922 /* do nothing. */
1923 ND6_STATS_INC(nd6.cachehit);
1924 } else {
1925 /* Search destination cache. */
1926 i = nd6_find_destination_cache_entry(ip6addr);
1927 if (i >= 0) {
1928 /* found destination entry. make it our new cached index. */
1929 nd6_cached_destination_index = i;
1930 } else {
1931 /* Not found. Create a new destination entry. */
1932 i = nd6_new_destination_cache_entry();
1933 if (i >= 0) {
1934 /* got new destination entry. make it our new cached index. */
1935 nd6_cached_destination_index = i;
1936 } else {
1937 /* Could not create a destination cache entry. */
1938 return ERR_MEM;
1939 }
1940  
1941 /* Copy dest address to destination cache. */
1942 ip6_addr_set(&(destination_cache[nd6_cached_destination_index].destination_addr), ip6addr);
1943  
1944 /* Now find the next hop. is it a neighbor? */
1945 if (ip6_addr_islinklocal(ip6addr) ||
1946 nd6_is_prefix_in_netif(ip6addr, netif)) {
1947 /* Destination in local link. */
1948 destination_cache[nd6_cached_destination_index].pmtu = netif->mtu;
1949 ip6_addr_copy(destination_cache[nd6_cached_destination_index].next_hop_addr, destination_cache[nd6_cached_destination_index].destination_addr);
1950 #ifdef LWIP_HOOK_ND6_GET_GW
1951 } else if ((next_hop_addr = LWIP_HOOK_ND6_GET_GW(netif, ip6addr)) != NULL) {
1952 /* Next hop for destination provided by hook function. */
1953 destination_cache[nd6_cached_destination_index].pmtu = netif->mtu;
1954 ip6_addr_set(&destination_cache[nd6_cached_destination_index].next_hop_addr, next_hop_addr);
1955 #endif /* LWIP_HOOK_ND6_GET_GW */
1956 } else {
1957 /* We need to select a router. */
1958 i = nd6_select_router(ip6addr, netif);
1959 if (i < 0) {
1960 /* No router found. */
1961 ip6_addr_set_any(&(destination_cache[nd6_cached_destination_index].destination_addr));
1962 return ERR_RTE;
1963 }
1964 destination_cache[nd6_cached_destination_index].pmtu = netif->mtu; /* Start with netif mtu, correct through ICMPv6 if necessary */
1965 ip6_addr_copy(destination_cache[nd6_cached_destination_index].next_hop_addr, default_router_list[i].neighbor_entry->next_hop_address);
1966 }
1967 }
1968 }
1969  
1970 #if LWIP_NETIF_HWADDRHINT
1971 if (netif->hints != NULL) {
1972 /* per-pcb cached entry was given */
1973 netif->hints->addr_hint = nd6_cached_destination_index;
1974 }
1975 #endif /* LWIP_NETIF_HWADDRHINT */
1976  
1977 /* Look in neighbor cache for the next-hop address. */
1978 if (ip6_addr_cmp(&(destination_cache[nd6_cached_destination_index].next_hop_addr),
1979 &(neighbor_cache[nd6_cached_neighbor_index].next_hop_address))) {
1980 /* Cache hit. */
1981 /* Do nothing. */
1982 ND6_STATS_INC(nd6.cachehit);
1983 } else {
1984 i = nd6_find_neighbor_cache_entry(&(destination_cache[nd6_cached_destination_index].next_hop_addr));
1985 if (i >= 0) {
1986 /* Found a matching record, make it new cached entry. */
1987 nd6_cached_neighbor_index = i;
1988 } else {
1989 /* Neighbor not in cache. Make a new entry. */
1990 i = nd6_new_neighbor_cache_entry();
1991 if (i >= 0) {
1992 /* got new neighbor entry. make it our new cached index. */
1993 nd6_cached_neighbor_index = i;
1994 } else {
1995 /* Could not create a neighbor cache entry. */
1996 return ERR_MEM;
1997 }
1998  
1999 /* Initialize fields. */
2000 ip6_addr_copy(neighbor_cache[i].next_hop_address,
2001 destination_cache[nd6_cached_destination_index].next_hop_addr);
2002 neighbor_cache[i].isrouter = 0;
2003 neighbor_cache[i].netif = netif;
2004 neighbor_cache[i].state = ND6_INCOMPLETE;
2005 neighbor_cache[i].counter.probes_sent = 1;
2006 nd6_send_neighbor_cache_probe(&neighbor_cache[i], ND6_SEND_FLAG_MULTICAST_DEST);
2007 }
2008 }
2009  
2010 /* Reset this destination's age. */
2011 destination_cache[nd6_cached_destination_index].age = 0;
2012  
2013 return nd6_cached_neighbor_index;
2014 }
2015  
2016 /**
2017 * Queue a packet for a neighbor.
2018 *
2019 * @param neighbor_index the index in the neighbor cache table
2020 * @param q packet to be queued
2021 * @return ERR_OK if succeeded, ERR_MEM if out of memory
2022 */
2023 static err_t
2024 nd6_queue_packet(s8_t neighbor_index, struct pbuf *q)
2025 {
2026 err_t result = ERR_MEM;
2027 struct pbuf *p;
2028 int copy_needed = 0;
2029 #if LWIP_ND6_QUEUEING
2030 struct nd6_q_entry *new_entry, *r;
2031 #endif /* LWIP_ND6_QUEUEING */
2032  
2033 if ((neighbor_index < 0) || (neighbor_index >= LWIP_ND6_NUM_NEIGHBORS)) {
2034 return ERR_ARG;
2035 }
2036  
2037 /* IF q includes a pbuf that must be copied, we have to copy the whole chain
2038 * into a new PBUF_RAM. See the definition of PBUF_NEEDS_COPY for details. */
2039 p = q;
2040 while (p) {
2041 if (PBUF_NEEDS_COPY(p)) {
2042 copy_needed = 1;
2043 break;
2044 }
2045 p = p->next;
2046 }
2047 if (copy_needed) {
2048 /* copy the whole packet into new pbufs */
2049 p = pbuf_alloc(PBUF_LINK, q->tot_len, PBUF_RAM);
2050 while ((p == NULL) && (neighbor_cache[neighbor_index].q != NULL)) {
2051 /* Free oldest packet (as per RFC recommendation) */
2052 #if LWIP_ND6_QUEUEING
2053 r = neighbor_cache[neighbor_index].q;
2054 neighbor_cache[neighbor_index].q = r->next;
2055 r->next = NULL;
2056 nd6_free_q(r);
2057 #else /* LWIP_ND6_QUEUEING */
2058 pbuf_free(neighbor_cache[neighbor_index].q);
2059 neighbor_cache[neighbor_index].q = NULL;
2060 #endif /* LWIP_ND6_QUEUEING */
2061 p = pbuf_alloc(PBUF_LINK, q->tot_len, PBUF_RAM);
2062 }
2063 if (p != NULL) {
2064 if (pbuf_copy(p, q) != ERR_OK) {
2065 pbuf_free(p);
2066 p = NULL;
2067 }
2068 }
2069 } else {
2070 /* referencing the old pbuf is enough */
2071 p = q;
2072 pbuf_ref(p);
2073 }
2074 /* packet was copied/ref'd? */
2075 if (p != NULL) {
2076 /* queue packet ... */
2077 #if LWIP_ND6_QUEUEING
2078 /* allocate a new nd6 queue entry */
2079 new_entry = (struct nd6_q_entry *)memp_malloc(MEMP_ND6_QUEUE);
2080 if ((new_entry == NULL) && (neighbor_cache[neighbor_index].q != NULL)) {
2081 /* Free oldest packet (as per RFC recommendation) */
2082 r = neighbor_cache[neighbor_index].q;
2083 neighbor_cache[neighbor_index].q = r->next;
2084 r->next = NULL;
2085 nd6_free_q(r);
2086 new_entry = (struct nd6_q_entry *)memp_malloc(MEMP_ND6_QUEUE);
2087 }
2088 if (new_entry != NULL) {
2089 new_entry->next = NULL;
2090 new_entry->p = p;
2091 if (neighbor_cache[neighbor_index].q != NULL) {
2092 /* queue was already existent, append the new entry to the end */
2093 r = neighbor_cache[neighbor_index].q;
2094 while (r->next != NULL) {
2095 r = r->next;
2096 }
2097 r->next = new_entry;
2098 } else {
2099 /* queue did not exist, first item in queue */
2100 neighbor_cache[neighbor_index].q = new_entry;
2101 }
2102 LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: queued packet %p on neighbor entry %"S16_F"\n", (void *)p, (s16_t)neighbor_index));
2103 result = ERR_OK;
2104 } else {
2105 /* the pool MEMP_ND6_QUEUE is empty */
2106 pbuf_free(p);
2107 LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: could not queue a copy of packet %p (out of memory)\n", (void *)p));
2108 /* { result == ERR_MEM } through initialization */
2109 }
2110 #else /* LWIP_ND6_QUEUEING */
2111 /* Queue a single packet. If an older packet is already queued, free it as per RFC. */
2112 if (neighbor_cache[neighbor_index].q != NULL) {
2113 pbuf_free(neighbor_cache[neighbor_index].q);
2114 }
2115 neighbor_cache[neighbor_index].q = p;
2116 LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: queued packet %p on neighbor entry %"S16_F"\n", (void *)p, (s16_t)neighbor_index));
2117 result = ERR_OK;
2118 #endif /* LWIP_ND6_QUEUEING */
2119 } else {
2120 LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: could not queue a copy of packet %p (out of memory)\n", (void *)q));
2121 /* { result == ERR_MEM } through initialization */
2122 }
2123  
2124 return result;
2125 }
2126  
2127 #if LWIP_ND6_QUEUEING
2128 /**
2129 * Free a complete queue of nd6 q entries
2130 *
2131 * @param q a queue of nd6_q_entry to free
2132 */
2133 static void
2134 nd6_free_q(struct nd6_q_entry *q)
2135 {
2136 struct nd6_q_entry *r;
2137 LWIP_ASSERT("q != NULL", q != NULL);
2138 LWIP_ASSERT("q->p != NULL", q->p != NULL);
2139 while (q) {
2140 r = q;
2141 q = q->next;
2142 LWIP_ASSERT("r->p != NULL", (r->p != NULL));
2143 pbuf_free(r->p);
2144 memp_free(MEMP_ND6_QUEUE, r);
2145 }
2146 }
2147 #endif /* LWIP_ND6_QUEUEING */
2148  
2149 /**
2150 * Send queued packets for a neighbor
2151 *
2152 * @param i the neighbor to send packets to
2153 */
2154 static void
2155 nd6_send_q(s8_t i)
2156 {
2157 struct ip6_hdr *ip6hdr;
2158 ip6_addr_t dest;
2159 #if LWIP_ND6_QUEUEING
2160 struct nd6_q_entry *q;
2161 #endif /* LWIP_ND6_QUEUEING */
2162  
2163 if ((i < 0) || (i >= LWIP_ND6_NUM_NEIGHBORS)) {
2164 return;
2165 }
2166  
2167 #if LWIP_ND6_QUEUEING
2168 while (neighbor_cache[i].q != NULL) {
2169 /* remember first in queue */
2170 q = neighbor_cache[i].q;
2171 /* pop first item off the queue */
2172 neighbor_cache[i].q = q->next;
2173 /* Get ipv6 header. */
2174 ip6hdr = (struct ip6_hdr *)(q->p->payload);
2175 /* Create an aligned copy. */
2176 ip6_addr_copy_from_packed(dest, ip6hdr->dest);
2177 /* Restore the zone, if applicable. */
2178 ip6_addr_assign_zone(&dest, IP6_UNKNOWN, neighbor_cache[i].netif);
2179 /* send the queued IPv6 packet */
2180 (neighbor_cache[i].netif)->output_ip6(neighbor_cache[i].netif, q->p, &dest);
2181 /* free the queued IP packet */
2182 pbuf_free(q->p);
2183 /* now queue entry can be freed */
2184 memp_free(MEMP_ND6_QUEUE, q);
2185 }
2186 #else /* LWIP_ND6_QUEUEING */
2187 if (neighbor_cache[i].q != NULL) {
2188 /* Get ipv6 header. */
2189 ip6hdr = (struct ip6_hdr *)(neighbor_cache[i].q->payload);
2190 /* Create an aligned copy. */
2191 ip6_addr_copy_from_packed(dest, ip6hdr->dest);
2192 /* Restore the zone, if applicable. */
2193 ip6_addr_assign_zone(&dest, IP6_UNKNOWN, neighbor_cache[i].netif);
2194 /* send the queued IPv6 packet */
2195 (neighbor_cache[i].netif)->output_ip6(neighbor_cache[i].netif, neighbor_cache[i].q, &dest);
2196 /* free the queued IP packet */
2197 pbuf_free(neighbor_cache[i].q);
2198 neighbor_cache[i].q = NULL;
2199 }
2200 #endif /* LWIP_ND6_QUEUEING */
2201 }
2202  
2203 /**
2204 * A packet is to be transmitted to a specific IPv6 destination on a specific
2205 * interface. Check if we can find the hardware address of the next hop to use
2206 * for the packet. If so, give the hardware address to the caller, which should
2207 * use it to send the packet right away. Otherwise, enqueue the packet for
2208 * later transmission while looking up the hardware address, if possible.
2209 *
2210 * As such, this function returns one of three different possible results:
2211 *
2212 * - ERR_OK with a non-NULL 'hwaddrp': the caller should send the packet now.
2213 * - ERR_OK with a NULL 'hwaddrp': the packet has been enqueued for later.
2214 * - not ERR_OK: something went wrong; forward the error upward in the stack.
2215 *
2216 * @param netif The lwIP network interface on which the IP packet will be sent.
2217 * @param q The pbuf(s) containing the IP packet to be sent.
2218 * @param ip6addr The destination IPv6 address of the packet.
2219 * @param hwaddrp On success, filled with a pointer to a HW address or NULL (meaning
2220 * the packet has been queued).
2221 * @return
2222 * - ERR_OK on success, ERR_RTE if no route was found for the packet,
2223 * or ERR_MEM if low memory conditions prohibit sending the packet at all.
2224 */
2225 err_t
2226 nd6_get_next_hop_addr_or_queue(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr, const u8_t **hwaddrp)
2227 {
2228 s8_t i;
2229  
2230 /* Get next hop record. */
2231 i = nd6_get_next_hop_entry(ip6addr, netif);
2232 if (i < 0) {
2233 /* failed to get a next hop neighbor record. */
2234 return i;
2235 }
2236  
2237 /* Now that we have a destination record, send or queue the packet. */
2238 if (neighbor_cache[i].state == ND6_STALE) {
2239 /* Switch to delay state. */
2240 neighbor_cache[i].state = ND6_DELAY;
2241 neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL;
2242 }
2243 /* @todo should we send or queue if PROBE? send for now, to let unicast NS pass. */
2244 if ((neighbor_cache[i].state == ND6_REACHABLE) ||
2245 (neighbor_cache[i].state == ND6_DELAY) ||
2246 (neighbor_cache[i].state == ND6_PROBE)) {
2247  
2248 /* Tell the caller to send out the packet now. */
2249 *hwaddrp = neighbor_cache[i].lladdr;
2250 return ERR_OK;
2251 }
2252  
2253 /* We should queue packet on this interface. */
2254 *hwaddrp = NULL;
2255 return nd6_queue_packet(i, q);
2256 }
2257  
2258  
2259 /**
2260 * Get the Path MTU for a destination.
2261 *
2262 * @param ip6addr the destination address
2263 * @param netif the netif on which the packet will be sent
2264 * @return the Path MTU, if known, or the netif default MTU
2265 */
2266 u16_t
2267 nd6_get_destination_mtu(const ip6_addr_t *ip6addr, struct netif *netif)
2268 {
2269 s8_t i;
2270  
2271 i = nd6_find_destination_cache_entry(ip6addr);
2272 if (i >= 0) {
2273 if (destination_cache[i].pmtu > 0) {
2274 return destination_cache[i].pmtu;
2275 }
2276 }
2277  
2278 if (netif != NULL) {
2279 return netif->mtu;
2280 }
2281  
2282 return 1280; /* Minimum MTU */
2283 }
2284  
2285  
2286 #if LWIP_ND6_TCP_REACHABILITY_HINTS
2287 /**
2288 * Provide the Neighbor discovery process with a hint that a
2289 * destination is reachable. Called by tcp_receive when ACKs are
2290 * received or sent (as per RFC). This is useful to avoid sending
2291 * NS messages every 30 seconds.
2292 *
2293 * @param ip6addr the destination address which is know to be reachable
2294 * by an upper layer protocol (TCP)
2295 */
2296 void
2297 nd6_reachability_hint(const ip6_addr_t *ip6addr)
2298 {
2299 s8_t i;
2300  
2301 /* Find destination in cache. */
2302 if (ip6_addr_cmp(ip6addr, &(destination_cache[nd6_cached_destination_index].destination_addr))) {
2303 i = nd6_cached_destination_index;
2304 ND6_STATS_INC(nd6.cachehit);
2305 } else {
2306 i = nd6_find_destination_cache_entry(ip6addr);
2307 }
2308 if (i < 0) {
2309 return;
2310 }
2311  
2312 /* Find next hop neighbor in cache. */
2313 if (ip6_addr_cmp(&(destination_cache[i].next_hop_addr), &(neighbor_cache[nd6_cached_neighbor_index].next_hop_address))) {
2314 i = nd6_cached_neighbor_index;
2315 ND6_STATS_INC(nd6.cachehit);
2316 } else {
2317 i = nd6_find_neighbor_cache_entry(&(destination_cache[i].next_hop_addr));
2318 }
2319 if (i < 0) {
2320 return;
2321 }
2322  
2323 /* For safety: don't set as reachable if we don't have a LL address yet. Misuse protection. */
2324 if (neighbor_cache[i].state == ND6_INCOMPLETE || neighbor_cache[i].state == ND6_NO_ENTRY) {
2325 return;
2326 }
2327  
2328 /* Set reachability state. */
2329 neighbor_cache[i].state = ND6_REACHABLE;
2330 neighbor_cache[i].counter.reachable_time = reachable_time;
2331 }
2332 #endif /* LWIP_ND6_TCP_REACHABILITY_HINTS */
2333  
2334 /**
2335 * Remove all prefix, neighbor_cache and router entries of the specified netif.
2336 *
2337 * @param netif points to a network interface
2338 */
2339 void
2340 nd6_cleanup_netif(struct netif *netif)
2341 {
2342 u8_t i;
2343 s8_t router_index;
2344 for (i = 0; i < LWIP_ND6_NUM_PREFIXES; i++) {
2345 if (prefix_list[i].netif == netif) {
2346 prefix_list[i].netif = NULL;
2347 }
2348 }
2349 for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) {
2350 if (neighbor_cache[i].netif == netif) {
2351 for (router_index = 0; router_index < LWIP_ND6_NUM_ROUTERS; router_index++) {
2352 if (default_router_list[router_index].neighbor_entry == &neighbor_cache[i]) {
2353 default_router_list[router_index].neighbor_entry = NULL;
2354 default_router_list[router_index].flags = 0;
2355 }
2356 }
2357 neighbor_cache[i].isrouter = 0;
2358 nd6_free_neighbor_cache_entry(i);
2359 }
2360 }
2361 /* Clear the destination cache, since many entries may now have become
2362 * invalid for one of several reasons. As destination cache entries have no
2363 * netif association, use a sledgehammer approach (this can be improved). */
2364 nd6_clear_destination_cache();
2365 }
2366  
2367 #if LWIP_IPV6_MLD
2368 /**
2369 * The state of a local IPv6 address entry is about to change. If needed, join
2370 * or leave the solicited-node multicast group for the address.
2371 *
2372 * @param netif The netif that owns the address.
2373 * @param addr_idx The index of the address.
2374 * @param new_state The new (IP6_ADDR_) state for the address.
2375 */
2376 void
2377 nd6_adjust_mld_membership(struct netif *netif, s8_t addr_idx, u8_t new_state)
2378 {
2379 u8_t old_state, old_member, new_member;
2380  
2381 old_state = netif_ip6_addr_state(netif, addr_idx);
2382  
2383 /* Determine whether we were, and should be, a member of the solicited-node
2384 * multicast group for this address. For tentative addresses, the group is
2385 * not joined until the address enters the TENTATIVE_1 (or VALID) state. */
2386 old_member = (old_state != IP6_ADDR_INVALID && old_state != IP6_ADDR_DUPLICATED && old_state != IP6_ADDR_TENTATIVE);
2387 new_member = (new_state != IP6_ADDR_INVALID && new_state != IP6_ADDR_DUPLICATED && new_state != IP6_ADDR_TENTATIVE);
2388  
2389 if (old_member != new_member) {
2390 ip6_addr_set_solicitednode(&multicast_address, netif_ip6_addr(netif, addr_idx)->addr[3]);
2391 ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif);
2392  
2393 if (new_member) {
2394 mld6_joingroup_netif(netif, &multicast_address);
2395 } else {
2396 mld6_leavegroup_netif(netif, &multicast_address);
2397 }
2398 }
2399 }
2400 #endif /* LWIP_IPV6_MLD */
2401  
2402 #endif /* LWIP_IPV6 */