ipv6_routing_table.c

00001 /*
00002  * Copyright (c) 2012-2017, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 /*
00018  * ipv6_routing_table.c
00019  *
00020  *  Implements IPv6 Neighbour Cache (RFC 4861), Destination Cache (RFC 4861),
00021  *  and Routing Table (RFC 4191, incorporating the RFC 4861 Prefix List)
00022  *
00023  * Note that RFC 4861 dictates that the Prefix List is checked first,
00024  * followed by the Default Router List. In simple host scenarios, the
00025  * longest-match routing table look-up achieves that, because on-link entries
00026  * from the Prefix List are longer than the ::/0 default routes.
00027  *
00028  * In more complex scenarios, we can have more-specific routes preferred over
00029  * more general on-link prefixes, eg the border router preferring a /128 RPL
00030  * DAO-SR route instead of the /64 on-link prefix for the Ethernet backbone.
00031  *
00032  */
00033 #include "nsconfig.h"
00034 #include "ns_types.h"
00035 #include "common_functions.h"
00036 #include "ip6string.h"
00037 #include "randLIB.h"
00038 #include "ns_trace.h"
00039 #include "string.h"
00040 #include "Core/include/address.h"
00041 #include "ipv6_stack/ipv6_routing_table.h"
00042 #include "Common_Protocols/ipv6_constants.h"
00043 #include "Common_Protocols/icmpv6.h"
00044 #include "nsdynmemLIB.h"
00045 #include "Service_Libs/etx/etx.h"
00046 #include "Common_Protocols/ipv6_resolution.h"
00047 #include <stdarg.h>
00048 #include <stdio.h>
00049 
00050 #define TRACE_GROUP "rout"
00051 
00052 #define NCACHE_GC_PERIOD    20  /* seconds */
00053 #define DCACHE_GC_PERIOD    20  /* seconds */
00054 
00055 static uint16_t current_max_cache = 64;
00056 
00057 /* We track "lifetime" of garbage-collectible entries, resetting
00058  * when used. Entries with lifetime 0 are favoured
00059  * for garbage-collection. */
00060 #define NCACHE_GC_AGE 600   /* 10 minutes (1s units - decremented every slow timer call) */
00061 #define DCACHE_GC_AGE 30    /* 10 minutes (20s units - decremented once per periodic GC) */
00062 #define DCACHE_GC_AGE_LL 6  /* 2 minutes for link-local destinations */
00063 
00064 /* For probable routers, consider them unreachable if ETX is greater than this */
00065 #define ETX_REACHABILITY_THRESHOLD 0x200    /* 8.8 fixed-point, so 2 */
00066 
00067 static NS_LIST_DEFINE(ipv6_destination_cache, ipv6_destination_t, link);
00068 static NS_LIST_DEFINE(ipv6_routing_table, ipv6_route_t, link);
00069 
00070 static ipv6_destination_t *ipv6_destination_lookup(const uint8_t *address, int8_t interface_id);
00071 static void ipv6_destination_cache_forget_router(ipv6_neighbour_cache_t *cache, const uint8_t neighbour_addr[16]);
00072 static void ipv6_destination_cache_forget_neighbour(const ipv6_neighbour_t *neighbour);
00073 static void ipv6_destination_release(ipv6_destination_t *dest);
00074 static void ipv6_route_table_remove_router(int8_t interface_id, const uint8_t *addr, ipv6_route_src_t source);
00075 static uint16_t total_metric(const ipv6_route_t *route);
00076 static void trace_debug_print(const char *fmt, ...);
00077 static uint8_t ipv6_route_table_count_source(int8_t interface_id, ipv6_route_src_t source);
00078 static void ipv6_route_table_remove_last_one_from_source(int8_t interface_id, ipv6_route_src_t source);
00079 static uint8_t ipv6_route_table_get_max_entries(int8_t interface_id, ipv6_route_src_t source);
00080 
00081 static uint16_t dcache_gc_timer;
00082 
00083 static uint16_t cache_long_term(bool is_destination)
00084 {
00085     uint16_t value = current_max_cache/8;
00086     if (is_destination) {
00087         value*=2;
00088     }
00089     if (value < 4) {
00090         value = 4;
00091     }
00092     return value;
00093 }
00094 
00095 static uint16_t cache_short_term(bool is_destination)
00096 {
00097     uint16_t value = current_max_cache/2;
00098     if (value < cache_long_term(is_destination)) {
00099         return cache_long_term(is_destination);
00100     }
00101     return value;
00102 }
00103 
00104 static uint32_t next_probe_time(ipv6_neighbour_cache_t *cache, uint_fast8_t retrans_num)
00105 {
00106     uint32_t t = cache->retrans_timer;
00107 
00108     while (retrans_num--) {
00109         t *= BACKOFF_MULTIPLE;
00110         if (t > MAX_RETRANS_TIMER) {
00111             t = MAX_RETRANS_TIMER;
00112             break;
00113         }
00114     }
00115 
00116     return randLIB_randomise_base(t, 0x4000, 0xBFFF);
00117 }
00118 
00119 int8_t ipv6_neighbour_set_current_max_cache(uint16_t max_cache)
00120 {
00121     if (max_cache < 4) {
00122         return -1;
00123     }
00124     current_max_cache = max_cache;
00125     return 0;
00126 }
00127 
00128 /* Called when we determine a neighbour is no longer a router */
00129 void ipv6_router_gone(ipv6_neighbour_cache_t *cache, ipv6_neighbour_t *entry)
00130 {
00131     tr_debug("Router gone: %s", trace_ipv6(entry->ip_address));
00132     entry->is_router = false;
00133     /* Only delete RA routes to satisfy RFC 4861. We should have a callback to
00134      * other route providers here - eg RPL might want to know, and delete from
00135      * the Candidate Neighbour set. But unfortunately our 6LoWPAN-ND routers do
00136      * currently send RS packets while running, which means this would break
00137      * stuff. We get spurious switches of IsRouter to false :(
00138      */
00139     ipv6_route_table_remove_router(cache->interface_id, entry->ip_address, ROUTE_RADV);
00140     /* The above will re-evaluate all destinations affected by the routing
00141      * change; the below is needed to also forget redirections to the router.
00142      */
00143     ipv6_destination_cache_forget_router(cache, entry->ip_address);
00144 }
00145 
00146 /* Called when a neighbour has apparently become reachable */
00147 static void ipv6_neighbour_appeared(ipv6_neighbour_cache_t *cache, uint8_t address[static 16])
00148 {
00149     (void)cache;
00150     (void)address;
00151 }
00152 
00153 /* Called when a neighbour has apparently become unreachable */
00154 static void ipv6_neighbour_gone(ipv6_neighbour_cache_t *cache, uint8_t address[static 16])
00155 {
00156     (void) cache;
00157     tr_debug("Lost contact with neighbour: %s", trace_ipv6(address));
00158     // We can keep trying to talk directly to that neighbour, but should
00159     // avoid using it any more as a router, if there's an alternative.
00160     ipv6_destination_cache_forget_router(cache, address);
00161 }
00162 
00163 void ipv6_neighbour_cache_init(ipv6_neighbour_cache_t *cache, int8_t interface_id)
00164 {
00165     /* Init Double linked Routing Table */
00166     ns_list_foreach_safe(ipv6_neighbour_t, cur, &cache->list) {
00167         ipv6_neighbour_entry_remove(cache, cur);
00168     }
00169     cache->gc_timer = NCACHE_GC_PERIOD;
00170     cache->retrans_timer = 1000;
00171     cache->max_ll_len = 0;
00172     cache->interface_id = interface_id;
00173     cache->recv_addr_reg = false;
00174     cache->send_addr_reg = false;
00175     cache->send_nud_probes = true;
00176     cache->recv_na_aro = false;
00177     cache->recv_ns_aro = false;
00178     cache->route_if_info.metric = 0;
00179     memset(cache->route_if_info.sources, 0, sizeof(cache->route_if_info.sources));
00180 }
00181 
00182 void ipv6_neighbour_cache_flush(ipv6_neighbour_cache_t *cache)
00183 {
00184     /* Flush non-registered entries only */
00185     ns_list_foreach_safe(ipv6_neighbour_t, cur, &cache->list) {
00186         if (cur->type == IP_NEIGHBOUR_GARBAGE_COLLECTIBLE) {
00187             ipv6_neighbour_entry_remove(cache, cur);
00188         }
00189     }
00190 }
00191 
00192 
00193 ipv6_neighbour_t *ipv6_neighbour_lookup(ipv6_neighbour_cache_t *cache, const uint8_t *address)
00194 {
00195     ns_list_foreach(ipv6_neighbour_t, cur, &cache->list) {
00196         if (addr_ipv6_equal(cur->ip_address, address)) {
00197             return cur;
00198         }
00199     }
00200 
00201     return NULL;
00202 }
00203 
00204 ipv6_neighbour_t *ipv6_neighbour_lookup_by_interface_id(int8_t interface_id, const uint8_t *address)
00205 {
00206     ipv6_neighbour_cache_t *ncache = ipv6_neighbour_cache_by_interface_id(interface_id);
00207     if (!ncache) {
00208         return NULL;
00209     }
00210 
00211     return ipv6_neighbour_lookup(ncache, address);
00212 }
00213 
00214 
00215 void ipv6_neighbour_entry_remove(ipv6_neighbour_cache_t *cache, ipv6_neighbour_t *entry)
00216 {
00217     /* Remove entry from cache first - avoids weird garbage collection issues, like
00218      * it being pushed out while generating ICMP errors, or ICMP errors actually using
00219      * the entry.
00220      */
00221     ns_list_remove(&cache->list, entry);
00222     switch (entry->state) {
00223         case IP_NEIGHBOUR_NEW:
00224             break;
00225         case IP_NEIGHBOUR_INCOMPLETE:
00226             /* If the NCE is discarded, the queued packet must also be discarded */
00227             /* Handle this here to avoid leakage in the event that the NCE is */
00228             /* dropped by garbage collection rather than the expected timeout */
00229             ipv6_interface_resolution_failed(cache, entry);
00230             break;
00231         case IP_NEIGHBOUR_STALE:
00232         case IP_NEIGHBOUR_REACHABLE:
00233         case IP_NEIGHBOUR_DELAY:
00234         case IP_NEIGHBOUR_PROBE:
00235         case IP_NEIGHBOUR_UNREACHABLE:
00236             /* Destination cache no longer has direct pointers to neighbour cache,
00237              * so a NCE being deleted no longer necessarily needs any special
00238              * action. Neighbour GC needn't affect the Dest Cache.
00239              */
00240             // ipv6_neighbour_gone(cache, entry);
00241             break;
00242     }
00243     ipv6_destination_cache_forget_neighbour(entry);
00244     ns_dyn_mem_free(entry);
00245 }
00246 
00247 ipv6_neighbour_t *ipv6_neighbour_lookup_or_create(ipv6_neighbour_cache_t *cache, const uint8_t *address/*, bool tentative*/)
00248 {
00249     uint_fast16_t count = 0;
00250     ipv6_neighbour_t *entry = NULL;
00251 
00252     ns_list_foreach(ipv6_neighbour_t, cur, &cache->list) {
00253         count++;
00254         if (addr_ipv6_equal(cur->ip_address, address)) {
00255             if (cur != ns_list_get_first(&cache->list)) {
00256                 ns_list_remove(&cache->list, cur);
00257                 ns_list_add_to_start(&cache->list, cur);
00258             }
00259             return cur;
00260         }
00261     }
00262 
00263     if (count >= current_max_cache) {
00264         entry = ns_list_get_last(&cache->list);
00265         ipv6_neighbour_entry_remove(cache, entry);
00266     }
00267 
00268     // Allocate new - note we have a basic size, plus enough for the LL address,
00269     // plus another 8 for the EUI-64 of registration (RFC 6775). Note that in
00270     // the protocols, the link-layer address and EUI-64 are distinct. The
00271     // neighbour may be using a short link-layer address, not its EUI-64.
00272     entry = ns_dyn_mem_alloc(sizeof(ipv6_neighbour_t) + cache->max_ll_len + (cache->recv_addr_reg ? 8 : 0));
00273     if (!entry) {
00274         tr_warn("No mem!");
00275         return NULL;
00276     }
00277 
00278     memcpy(entry->ip_address, address, 16);
00279     entry->is_router = false;
00280     entry->from_redirect = false;
00281     entry->state = IP_NEIGHBOUR_NEW;
00282     /*if (tentative && cache->reg_required)
00283         entry->type = IP_NEIGHBOUR_TENTATIVE;
00284     else*/
00285     entry->type = IP_NEIGHBOUR_GARBAGE_COLLECTIBLE;
00286     ns_list_init(&entry->queue);
00287     entry->timer = 0;
00288     entry->lifetime = 0;
00289     entry->retrans_count = 0;
00290     entry->ll_type = ADDR_NONE ;
00291     if (cache->recv_addr_reg) {
00292         memset(ipv6_neighbour_eui64(cache, entry), 0, 8);
00293     }
00294 
00295     ns_list_add_to_start(&cache->list, entry);
00296 
00297     return entry;
00298 }
00299 
00300 ipv6_neighbour_t *ipv6_neighbour_lookup_or_create_by_interface_id(int8_t interface_id, const uint8_t *address/*, bool tentative*/)
00301 {
00302     ipv6_neighbour_cache_t *ncache = ipv6_neighbour_cache_by_interface_id(interface_id);
00303     if (!ncache) {
00304         return NULL;
00305     }
00306 
00307     return ipv6_neighbour_lookup_or_create(ncache, address/*, tentative*/);
00308 }
00309 
00310 ipv6_neighbour_t *ipv6_neighbour_used(ipv6_neighbour_cache_t *cache, ipv6_neighbour_t *entry)
00311 {
00312     /* Reset the GC life, if it's a GC entry */
00313     if (entry->type == IP_NEIGHBOUR_GARBAGE_COLLECTIBLE) {
00314         entry->lifetime = NCACHE_GC_AGE;
00315     }
00316 
00317     /* Move it to the front of the list */
00318     if (entry != ns_list_get_first(&cache->list)) {
00319         ns_list_remove(&cache->list, entry);
00320         ns_list_add_to_start(&cache->list, entry);
00321     }
00322 
00323     /* If the entry is stale, prepare delay timer for active NUD probe */
00324     if (entry->state == IP_NEIGHBOUR_STALE && cache->send_nud_probes) {
00325         ipv6_neighbour_set_state(cache, entry, IP_NEIGHBOUR_DELAY);
00326     }
00327 
00328     /* Special case for Registered Unreachable entries - restart the probe timer if stopped */
00329     else if (entry->state == IP_NEIGHBOUR_UNREACHABLE && entry->timer == 0) {
00330         entry->timer = next_probe_time(cache, entry->retrans_count);
00331     }
00332 
00333     return entry;
00334 }
00335 
00336 static bool ipv6_neighbour_state_is_probably_reachable(ip_neighbour_cache_state_t state)
00337 {
00338     switch (state) {
00339         case IP_NEIGHBOUR_NEW:
00340         case IP_NEIGHBOUR_INCOMPLETE:
00341         case IP_NEIGHBOUR_UNREACHABLE:
00342             return false;
00343         case IP_NEIGHBOUR_REACHABLE:
00344         case IP_NEIGHBOUR_STALE:
00345         case IP_NEIGHBOUR_DELAY:
00346         case IP_NEIGHBOUR_PROBE:
00347             return true;
00348     }
00349     return false;
00350 }
00351 
00352 bool ipv6_neighbour_is_probably_reachable(ipv6_neighbour_cache_t *cache, ipv6_neighbour_t *n)
00353 {
00354     if (!n) {
00355         return false;
00356     }
00357     if (!ipv6_neighbour_state_is_probably_reachable(n->state)) {
00358         return false;
00359     }
00360     uint16_t etx = ipv6_map_ip_to_ll_and_call_ll_addr_handler(NULL, cache->interface_id, n, n->ip_address, etx_read);
00361     if (etx > ETX_REACHABILITY_THRESHOLD) {
00362         /* "Unknown" is signalled as low values, so will be return "true" */
00363         return false;
00364     }
00365     return true;
00366 }
00367 
00368 bool ipv6_neighbour_addr_is_probably_reachable(ipv6_neighbour_cache_t *cache, const uint8_t *address)
00369 {
00370     return ipv6_neighbour_is_probably_reachable(cache, ipv6_neighbour_lookup(cache, address));
00371 }
00372 
00373 bool ipv6_neighbour_ll_addr_match(const ipv6_neighbour_t *entry, addrtype_t ll_type, const uint8_t *ll_address)
00374 {
00375     return ll_type == entry->ll_type && memcmp(entry->ll_address, ll_address, addr_len_from_type(ll_type)) == 0;
00376 }
00377 
00378 static bool ipv6_neighbour_update_ll(ipv6_neighbour_t *entry, addrtype_t ll_type, const uint8_t *ll_address)
00379 {
00380     uint8_t ll_len = addr_len_from_type(ll_type);
00381 
00382     /* Any new address info clears the "redirected" flag - redirect itself
00383      * sets it again after this is called.
00384      */
00385     entry->from_redirect = false;
00386 
00387     if (ll_type != entry->ll_type || memcmp(entry->ll_address, ll_address, ll_len)) {
00388         entry->ll_type = ll_type;
00389         memcpy(entry->ll_address, ll_address, ll_len);
00390         return true;
00391     }
00392     return false;
00393 }
00394 
00395 void ipv6_neighbour_invalidate_ll_addr(ipv6_neighbour_cache_t *cache, addrtype_t ll_type, const uint8_t *ll_address)
00396 {
00397     ns_list_foreach_safe(ipv6_neighbour_t, cur, &cache->list) {
00398         if (cur->type == IP_NEIGHBOUR_GARBAGE_COLLECTIBLE && ipv6_neighbour_ll_addr_match(cur, ll_type, ll_address)) {
00399             ipv6_neighbour_entry_remove(cache, cur);
00400         }
00401     }
00402 }
00403 
00404 void ipv6_neighbour_set_state(ipv6_neighbour_cache_t *cache, ipv6_neighbour_t *entry, ip_neighbour_cache_state_t state)
00405 {
00406     if (!ipv6_neighbour_state_is_probably_reachable(entry->state) &&
00407             ipv6_neighbour_state_is_probably_reachable(state)) {
00408         /* A neighbour is becoming reachable - may affect destination cache */
00409         ipv6_neighbour_appeared(cache, entry->ip_address);
00410     }
00411     switch (state) {
00412         case IP_NEIGHBOUR_INCOMPLETE:
00413             entry->retrans_count = 0;
00414             entry->timer = cache->retrans_timer;
00415             break;
00416         case IP_NEIGHBOUR_STALE:
00417             entry->timer = 0;
00418             break;
00419         case IP_NEIGHBOUR_DELAY:
00420             entry->timer = DELAY_FIRST_PROBE_TIME;
00421             break;
00422         case IP_NEIGHBOUR_PROBE:
00423             entry->retrans_count = 0;
00424             entry->timer = next_probe_time(cache, 0);
00425             break;
00426         case IP_NEIGHBOUR_REACHABLE:
00427             entry->timer = cache->reachable_time;
00428             break;
00429         case IP_NEIGHBOUR_UNREACHABLE:
00430             /* Progress to this from PROBE - timers continue */
00431             ipv6_neighbour_gone(cache, entry->ip_address);
00432             break;
00433         default:
00434             entry->timer = 0;
00435             break;
00436     }
00437     entry->state = state;
00438 }
00439 
00440 /* Called when LL address information is received other than in an NA (NS source, RS source, RA source, Redirect target) */
00441 void ipv6_neighbour_entry_update_unsolicited(ipv6_neighbour_cache_t *cache, ipv6_neighbour_t *entry, addrtype_t type, const uint8_t *ll_address/*, bool tentative*/)
00442 {
00443     bool modified_ll = ipv6_neighbour_update_ll(entry, type, ll_address);
00444 
00445     switch (entry->state) {
00446         case IP_NEIGHBOUR_NEW:
00447             ipv6_neighbour_set_state(cache, entry, IP_NEIGHBOUR_STALE);
00448             break;
00449         case IP_NEIGHBOUR_INCOMPLETE:
00450             ipv6_neighbour_set_state(cache, entry, IP_NEIGHBOUR_STALE);
00451             ipv6_send_queued(entry);
00452             break;
00453         default:
00454             if (modified_ll) {
00455                 ipv6_neighbour_set_state(cache, entry, IP_NEIGHBOUR_STALE);
00456             }
00457             break;
00458     }
00459 }
00460 
00461 ipv6_neighbour_t *ipv6_neighbour_update_unsolicited(ipv6_neighbour_cache_t *cache, const uint8_t *ip_address, addrtype_t type, const uint8_t *ll_address/*, bool tentative*/)
00462 {
00463     ipv6_neighbour_t *entry = ipv6_neighbour_lookup_or_create(cache, ip_address/*, tentative*/);
00464     if (!entry) {
00465         return NULL;
00466     }
00467 
00468     ipv6_neighbour_entry_update_unsolicited(cache, entry, type, ll_address/*, tentative*/);
00469 
00470     return entry;
00471 }
00472 
00473 void ipv6_neighbour_update_from_na(ipv6_neighbour_cache_t *cache, ipv6_neighbour_t *entry, uint8_t flags, addrtype_t ll_type, const uint8_t *ll_address)
00474 {
00475     if (entry->state == IP_NEIGHBOUR_NEW || entry->state == IP_NEIGHBOUR_INCOMPLETE) {
00476         entry->is_router = flags & NA_R;
00477         if (ll_type == ADDR_NONE ) {
00478             return;
00479         }
00480 
00481         ipv6_neighbour_update_ll(entry, ll_type, ll_address);
00482         if (flags & NA_S) {
00483             ipv6_neighbour_set_state(cache, entry, IP_NEIGHBOUR_REACHABLE);
00484         } else {
00485             ipv6_neighbour_set_state(cache, entry, IP_NEIGHBOUR_STALE);
00486         }
00487         ipv6_send_queued(entry);
00488         return;
00489     }
00490 
00491     /* Already have a complete entry with known LL address */
00492     bool ll_addr_differs = ll_type != ADDR_NONE  && !ipv6_neighbour_ll_addr_match(entry, ll_type, ll_address);
00493 
00494     if (ll_addr_differs) {
00495         if (flags & NA_O) {
00496             entry->ll_type = ll_type;
00497             memcpy(entry->ll_address, ll_address, addr_len_from_type(ll_type));
00498         } else {
00499             if (entry->state == IP_NEIGHBOUR_REACHABLE) {
00500                 ipv6_neighbour_set_state(cache, entry, IP_NEIGHBOUR_STALE);
00501             }
00502             return;
00503         }
00504     }
00505 
00506     if (flags & NA_S) {
00507         ipv6_neighbour_set_state(cache, entry, IP_NEIGHBOUR_REACHABLE);
00508     } else if (ll_addr_differs) {
00509         ipv6_neighbour_set_state(cache, entry, IP_NEIGHBOUR_STALE);
00510     }
00511 
00512     if (entry->is_router && !(flags & NA_R)) {
00513         ipv6_router_gone(cache, entry);
00514     }
00515 
00516     entry->is_router = flags & NA_R;
00517 }
00518 
00519 void ipv6_neighbour_reachability_confirmation(const uint8_t ip_address[static 16], int8_t interface_id)
00520 {
00521     /* No point creating an entry if doesn't exist */
00522     ipv6_destination_t *dest = ipv6_destination_lookup(ip_address, interface_id);
00523     if (!dest) {
00524         return;
00525     }
00526 
00527     /* We can't be absolutely certain which next hop is working, but last_neighbour is our best guess */
00528     ipv6_neighbour_t *next_hop = dest->last_neighbour;
00529 #if 0
00530     if (next_hop) {
00531         tr_debug("%s rconf: mark %s reachable", trace_ipv6(ip_address), trace_ipv6(next_hop->ip_address));
00532     } else {
00533         tr_debug("%s rconf: next hop unknown", trace_ipv6(ip_address));
00534     }
00535 #endif
00536     if (!next_hop) {
00537         return;
00538     }
00539 
00540     ipv6_neighbour_cache_t *ncache = ipv6_neighbour_cache_by_interface_id(dest->interface_id);
00541     if (!ncache) {
00542         return;
00543     }
00544 
00545     if (next_hop->state != IP_NEIGHBOUR_NEW && next_hop->state != IP_NEIGHBOUR_INCOMPLETE) {
00546         ipv6_neighbour_set_state(ncache, next_hop, IP_NEIGHBOUR_REACHABLE);
00547     }
00548 }
00549 
00550 /* RFC 4861 doesn't have this, but would seem sensible to at least nudge it out of REACHABLE state.
00551  * This doesn't add a new state machine transition, we just cut short the timer.
00552  * This should normally be called /before/ initiating a retransmit, so the
00553  * retransmit then triggers an immediate transition into DELAY state.
00554  */
00555 void ipv6_neighbour_reachability_problem(const uint8_t ip_address[static 16], int8_t interface_id)
00556 {
00557     /* No point creating an entry if doesn't exist */
00558     ipv6_destination_t *dest = ipv6_destination_lookup(ip_address, interface_id);
00559     if (!dest) {
00560         return;
00561     }
00562 
00563     /* We can't be absolutely certain which next hop has problems, but last_neighbour is our best guess */
00564     ipv6_neighbour_t *next_hop = dest->last_neighbour;
00565     if (!next_hop) {
00566         return;
00567     }
00568 
00569     ipv6_neighbour_cache_t *ncache = ipv6_neighbour_cache_by_interface_id(dest->interface_id);
00570     if (!ncache) {
00571         return;
00572     }
00573 
00574     if (next_hop->state == IP_NEIGHBOUR_REACHABLE) {
00575         ipv6_neighbour_set_state(ncache, next_hop, IP_NEIGHBOUR_STALE);
00576     }
00577 }
00578 
00579 static const char *state_names[] = {
00580     [IP_NEIGHBOUR_NEW]          = "NEW",
00581     [IP_NEIGHBOUR_INCOMPLETE]   = "INCOMPLETE",
00582     [IP_NEIGHBOUR_STALE]        = "STALE",
00583     [IP_NEIGHBOUR_REACHABLE]    = "REACHABLE",
00584     [IP_NEIGHBOUR_DELAY]        = "DELAY",
00585     [IP_NEIGHBOUR_PROBE]        = "PROBE",
00586     [IP_NEIGHBOUR_UNREACHABLE]  = "UNREACHABLE",
00587 };
00588 
00589 static const char *type_names[] = {
00590     [IP_NEIGHBOUR_GARBAGE_COLLECTIBLE]  = "GC",
00591     [IP_NEIGHBOUR_REGISTERED]           = "REGISTERED",
00592     [IP_NEIGHBOUR_TENTATIVE]            = "TENTATIVE",
00593 };
00594 
00595 static void sprint_array(char *s, const uint8_t *ptr, uint_fast8_t len)
00596 {
00597     if (len == 0) {
00598         *s = '\0';
00599         return;
00600     }
00601 
00602     for (uint_fast8_t i = 0; i < len; i++) {
00603         s += sprintf(s, "%02x:", *ptr++);
00604     }
00605     // Replace last ':' with '\0'
00606     *(s - 1) = '\0';
00607 }
00608 
00609 void ipv6_neighbour_cache_print(const ipv6_neighbour_cache_t *cache, route_print_fn_t *print_fn)
00610 {
00611     print_fn("Neighbour Cache %d", cache->interface_id);
00612     print_fn("Reachable Time: %"PRIu32"   Retrans Timer: %"PRIu32"   MTU: %"PRIu16"", cache->reachable_time, cache->retrans_timer, cache->link_mtu);
00613     ns_list_foreach(const ipv6_neighbour_t, cur, &cache->list) {
00614         ROUTE_PRINT_ADDR_STR_BUFFER_INIT(addr_str);
00615         print_fn("%sIP Addr: %s", cur->is_router ? "Router " : "", ROUTE_PRINT_ADDR_STR_FORMAT(addr_str, cur->ip_address));
00616         // Reusing addr_str for the array prints as it's no longer needed and 41 bytes is more than enough.
00617         sprint_array(addr_str, cur->ll_address, addr_len_from_type(cur->ll_type));
00618         print_fn("LL Addr: (%s %"PRIu32") %s", state_names[cur->state], cur->timer, addr_str);
00619         if (cache->recv_addr_reg && memcmp(ipv6_neighbour_eui64(cache, cur), ADDR_EUI64_ZERO, 8)) {
00620             sprint_array( addr_str, ipv6_neighbour_eui64(cache, cur), 8);
00621             print_fn("EUI-64:  (%s %"PRIu32") %s", type_names[cur->type], cur->lifetime, addr_str);
00622         } else if (cur->type != IP_NEIGHBOUR_GARBAGE_COLLECTIBLE) {
00623             print_fn("         (%s %"PRIu32") [no EUI-64]", type_names[cur->type], cur->lifetime);
00624         }
00625     }
00626 }
00627 
00628 static void ipv6_neighbour_cache_gc_periodic(ipv6_neighbour_cache_t *cache)
00629 {
00630     uint_fast16_t gc_count = 0;
00631     ns_list_foreach_safe(ipv6_neighbour_t, entry, &cache->list) {
00632         if (entry->type == IP_NEIGHBOUR_GARBAGE_COLLECTIBLE) {
00633             gc_count++;
00634         }
00635     }
00636 
00637     if (gc_count <= cache_long_term(false)) {
00638         return;
00639     }
00640 
00641     /* Removal strategy - to stay below MAX_SHORT_TERM, we will chuck any STALE entries */
00642     /* To stay below MAX_LONG_TERM, we will chuck old STALE entries */
00643     ns_list_foreach_reverse_safe(ipv6_neighbour_t, entry, &cache->list) {
00644         /* Expiration of non-GC entries handled in slow timer routine */
00645         if (entry->type != IP_NEIGHBOUR_GARBAGE_COLLECTIBLE) {
00646             continue;
00647         }
00648 
00649         if (entry->state != IP_NEIGHBOUR_STALE && entry->state != IP_NEIGHBOUR_UNREACHABLE) {
00650             continue;
00651         }
00652 
00653         if (entry->lifetime == 0 || gc_count > cache_short_term(false)) {
00654             ipv6_neighbour_entry_remove(cache, entry);
00655             if (--gc_count <= cache_long_term(false)) {
00656                 break;
00657             }
00658         }
00659     }
00660 }
00661 
00662 void ipv6_neighbour_cache_slow_timer(ipv6_neighbour_cache_t *cache, uint8_t seconds)
00663 {
00664     ns_list_foreach_safe(ipv6_neighbour_t, cur, &cache->list) {
00665         if (cur->lifetime == 0 || cur->lifetime == 0xffffffff) {
00666             continue;
00667         }
00668 
00669         if (cur->lifetime > seconds) {
00670             cur->lifetime -= seconds;
00671             continue;
00672         }
00673 
00674         cur->lifetime = 0;
00675 
00676         /* Lifetime expired */
00677         switch (cur->type) {
00678             case IP_NEIGHBOUR_GARBAGE_COLLECTIBLE:
00679                 /* No immediate action, but 0 lifetime is an input to the GC */
00680                 break;
00681 
00682             case IP_NEIGHBOUR_TENTATIVE:
00683             case IP_NEIGHBOUR_REGISTERED:
00684                 /* These are deleted as soon as lifetime expires */
00685                 ipv6_neighbour_gone(cache, cur->ip_address);
00686                 ipv6_neighbour_entry_remove(cache, cur);
00687                 break;
00688         }
00689     }
00690 
00691     if (cache->gc_timer > seconds) {
00692         cache->gc_timer -= seconds;
00693         return;
00694     }
00695 
00696     cache->gc_timer = NCACHE_GC_PERIOD;
00697     //ipv6_neighbour_cache_print(cache);
00698     ipv6_neighbour_cache_gc_periodic(cache);
00699 }
00700 
00701 void ipv6_neighbour_cache_fast_timer(ipv6_neighbour_cache_t *cache, uint16_t ticks)
00702 {
00703     uint32_t ms = (uint32_t) ticks * 100;
00704 
00705     ns_list_foreach_safe(ipv6_neighbour_t, cur, &cache->list) {
00706         if (cur->timer == 0) {
00707             continue;
00708         }
00709 
00710         if (cur->timer > ms) {
00711             cur->timer -= ms;
00712             continue;
00713         }
00714 
00715         cur->timer = 0;
00716 
00717         /* Timer expired */
00718         switch (cur->state) {
00719             case IP_NEIGHBOUR_NEW:
00720                 /* Shouldn't happen */
00721                 break;
00722             case IP_NEIGHBOUR_INCOMPLETE:
00723                 if (++cur->retrans_count >= MAX_MULTICAST_SOLICIT) {
00724                     /* Should be safe for registration - Tentative/Registered entries can't be INCOMPLETE */
00725                     ipv6_neighbour_gone(cache, cur->ip_address);
00726                     ipv6_neighbour_entry_remove(cache, cur);
00727                 } else {
00728                     ipv6_interface_resolve_send_ns(cache, cur, false, cur->retrans_count);
00729                     cur->timer = cache->retrans_timer;
00730                 }
00731                 break;
00732             case IP_NEIGHBOUR_STALE:
00733                 /* Shouldn't happen */
00734                 break;
00735             case IP_NEIGHBOUR_REACHABLE:
00736                 ipv6_neighbour_set_state(cache, cur, IP_NEIGHBOUR_STALE);
00737                 break;
00738             case IP_NEIGHBOUR_DELAY:
00739                 ipv6_neighbour_set_state(cache, cur, IP_NEIGHBOUR_PROBE);
00740                 ipv6_interface_resolve_send_ns(cache, cur, true, 0);
00741                 break;
00742             case IP_NEIGHBOUR_PROBE:
00743                 if (cur->retrans_count >= MARK_UNREACHABLE - 1) {
00744                     if (cur->from_redirect) {
00745                         ipv6_neighbour_gone(cache, cur->ip_address);
00746                         ipv6_neighbour_entry_remove(cache, cur);
00747                         break;
00748                     } else {
00749                         ipv6_neighbour_set_state(cache, cur, IP_NEIGHBOUR_UNREACHABLE);
00750                     }
00751                 }
00752             /* no break */
00753             case IP_NEIGHBOUR_UNREACHABLE:
00754                 if (cur->retrans_count < 0xFF) {
00755                     cur->retrans_count++;
00756                 }
00757 
00758                 if (cur->retrans_count >= MAX_UNICAST_SOLICIT && cur->type == IP_NEIGHBOUR_GARBAGE_COLLECTIBLE) {
00759                     ipv6_neighbour_entry_remove(cache, cur);
00760                 } else {
00761                     ipv6_interface_resolve_send_ns(cache, cur, true, cur->retrans_count);
00762                     if (cur->retrans_count >= MAX_UNICAST_SOLICIT - 1) {
00763                         /* "Final" unicast probe */
00764                         if (cur->type == IP_NEIGHBOUR_GARBAGE_COLLECTIBLE) {
00765                             /* Only wait 1 initial retrans time for response to final probe - don't want backoff in this case */
00766                             cur->timer = cache->retrans_timer;
00767                         } else {
00768                             /* We're not going to remove this. Let's stop the timer. We'll restart to probe once more if it's used */
00769                             cur->timer = 0;
00770                         }
00771                     } else {
00772                         /* Backoff for the next probe */
00773                         cur->timer = next_probe_time(cache, cur->retrans_count);
00774                     }
00775                 }
00776                 break;
00777         }
00778     }
00779 }
00780 
00781 void ipv6_destination_cache_print(route_print_fn_t *print_fn)
00782 {
00783     print_fn("Destination Cache:");
00784     ns_list_foreach(ipv6_destination_t, entry, &ipv6_destination_cache) {
00785         ROUTE_PRINT_ADDR_STR_BUFFER_INIT(addr_str);
00786         print_fn(" %s (life %u)", ROUTE_PRINT_ADDR_STR_FORMAT(addr_str, entry->destination), entry->lifetime);
00787 #ifdef HAVE_IPV6_ND
00788         if (entry->redirected) {
00789             print_fn("     Redirect %s%%%u", ROUTE_PRINT_ADDR_STR_FORMAT(addr_str, entry->redirect_addr), entry->interface_id);
00790         }
00791 #endif
00792 #ifndef NO_IPV6_PMTUD
00793         print_fn("     PMTU %u (life %u)", entry->pmtu, entry->pmtu_lifetime);
00794 #endif
00795     }
00796 }
00797 
00798 static ipv6_destination_t *ipv6_destination_lookup(const uint8_t *address, int8_t interface_id)
00799 {
00800     bool is_ll = addr_is_ipv6_link_local(address);
00801 
00802     if (is_ll && interface_id == -1) {
00803         return NULL;
00804     }
00805 
00806     ns_list_foreach(ipv6_destination_t, cur, &ipv6_destination_cache) {
00807         if (!addr_ipv6_equal(cur->destination, address)) {
00808             continue;
00809         }
00810         /* For LL addresses, interface ID must also be compared */
00811         if (is_ll && cur->interface_id != interface_id) {
00812             continue;
00813         }
00814 
00815         return cur;
00816     }
00817 
00818     return NULL;
00819 }
00820 
00821 /* Unlike original version, this does NOT perform routing check - it's pure destination cache look-up
00822  *
00823  * We no longer attempt to cache route lookups in the destination cache, as
00824  * assumption that routing look-ups are keyed purely by destination is no longer
00825  * true. If necessary, a caching layer could be placed into
00826  * ipv6_route_choose_next_hop.
00827  *
00828  * Interface IDs are a little tricky here. Current situation is that we
00829  * require an interface ID for <=realm-local addresses, and it's ignored for
00830  * other addresses. That prevents us having multiple Destination Cache entries
00831  * for one global address.
00832  */
00833 ipv6_destination_t *ipv6_destination_lookup_or_create(const uint8_t *address, int8_t interface_id)
00834 {
00835     uint_fast16_t count = 0;
00836     ipv6_destination_t *entry = NULL;
00837     bool interface_specific = addr_ipv6_scope(address, NULL) <= IPV6_SCOPE_REALM_LOCAL;
00838 
00839     if (interface_specific && interface_id == -1) {
00840         return NULL;
00841     }
00842 
00843     /* Find any existing entry */
00844     ns_list_foreach(ipv6_destination_t, cur, &ipv6_destination_cache) {
00845         count++;
00846         if (!addr_ipv6_equal(cur->destination, address)) {
00847             continue;
00848         }
00849         /* For LL addresses, interface ID must also be compared */
00850         if (interface_specific && cur->interface_id != interface_id) {
00851             continue;
00852         }
00853 
00854         entry = cur;
00855         break;
00856     }
00857 
00858 
00859     if (!entry) {
00860         if (count > current_max_cache) {
00861             entry = ns_list_get_last(&ipv6_destination_cache);
00862             ns_list_remove(&ipv6_destination_cache, entry);
00863             ipv6_destination_release(entry);
00864         }
00865 
00866         /* If no entry, make one */
00867         entry = ns_dyn_mem_alloc(sizeof(ipv6_destination_t));
00868         if (!entry) {
00869             return NULL;
00870         }
00871         memcpy(entry->destination, address, 16);
00872         entry->refcount = 1;
00873 #ifdef HAVE_IPV6_ND
00874         entry->redirected = false;
00875 #endif
00876         entry->last_neighbour = NULL;
00877 #ifndef NO_IPV6_PMTUD
00878         entry->pmtu = 0xffff;
00879         entry->pmtu_lifetime = 0;
00880 #endif
00881 #ifndef NO_IP_FRAGMENT_TX
00882         entry->fragment_id = randLIB_get_32bit();
00883 #endif
00884         if (interface_specific) {
00885             entry->interface_id = interface_id;
00886         } else {
00887             entry->interface_id = -1;
00888         }
00889         ns_list_add_to_start(&ipv6_destination_cache, entry);
00890     } else if (entry != ns_list_get_first(&ipv6_destination_cache)) {
00891         /* If there was an entry, and it wasn't at the start, move it */
00892         ns_list_remove(&ipv6_destination_cache, entry);
00893         ns_list_add_to_start(&ipv6_destination_cache, entry);
00894     }
00895 
00896     if (addr_ipv6_scope(address, NULL) <= IPV6_SCOPE_LINK_LOCAL) {
00897         entry->lifetime = DCACHE_GC_AGE_LL;
00898     } else {
00899         entry->lifetime = DCACHE_GC_AGE;
00900     }
00901 
00902     return entry;
00903 }
00904 
00905 
00906 /* Force re-evaluation of next hop for all entries using the specified next hop as
00907  * a router. Will keep using it for direct comms.
00908  */
00909 static void ipv6_destination_cache_forget_router(ipv6_neighbour_cache_t *ncache, const uint8_t neighbour_addr[static 16])
00910 {
00911     ipv6_neighbour_t *neighbour = ipv6_neighbour_lookup(ncache, neighbour_addr);
00912 
00913     ns_list_foreach(ipv6_destination_t, entry, &ipv6_destination_cache) {
00914         if (entry->last_neighbour && entry->interface_id == ncache->interface_id && entry->last_neighbour == neighbour) {
00915             entry->last_neighbour = NULL;
00916         }
00917 #ifdef HAVE_IPV6_ND
00918         if (entry->redirected && entry->interface_id == ncache->interface_id && addr_ipv6_equal(entry->redirect_addr, neighbour_addr)) {
00919             entry->redirected = false;
00920         }
00921 #endif
00922     }
00923 }
00924 
00925 static void ipv6_destination_cache_forget_neighbour(const ipv6_neighbour_t *neighbour)
00926 {
00927     ns_list_foreach(ipv6_destination_t, entry, &ipv6_destination_cache) {
00928         if (entry->last_neighbour == neighbour) {
00929             entry->last_neighbour = NULL;
00930         }
00931     }
00932 }
00933 
00934 #ifdef HAVE_IPV6_ND
00935 void ipv6_destination_redirect(const uint8_t *dest_addr, const uint8_t *sender_addr, const uint8_t *redirect_addr, int8_t interface_id, addrtype_t ll_type, const uint8_t *ll_address)
00936 {
00937     ipv6_destination_t *dest_entry = ipv6_destination_lookup_or_create(dest_addr, interface_id);
00938     ipv6_neighbour_cache_t *ncache = ipv6_neighbour_cache_by_interface_id(interface_id);
00939     bool to_router;
00940 
00941     if (!dest_entry || !ncache) {
00942         tr_warn("Redirect failure - no dest entry/ncache");
00943         return;
00944     }
00945 
00946     if (!dest_entry->last_neighbour || dest_entry->interface_id != interface_id || !addr_ipv6_equal(dest_entry->last_neighbour->ip_address, sender_addr)) {
00947         tr_warn("Redirect not sent from current next hop");
00948         return;
00949     }
00950 
00951     if (addr_ipv6_equal(redirect_addr, dest_addr)) {
00952         /* We're being told it is on-link */
00953         to_router = false;
00954     } else if (addr_is_ipv6_link_local(redirect_addr)) {
00955         /* We're being sent to a different router */
00956         to_router = true;
00957     } else {
00958         tr_debug("Invalid redirection: %s", trace_ipv6(redirect_addr));
00959         return;
00960     }
00961 
00962     // XXX need to consider invalidating/preserving other information?
00963     // Possibly not as we should only be handling this if not a router, so no
00964     // possibility of screwing up RPL. Although the "am I a router" check isn't
00965     // in place...
00966     dest_entry->redirected = true;
00967     memcpy(dest_entry->redirect_addr, redirect_addr, 16);
00968 
00969     ipv6_neighbour_t *ncache_entry = NULL;
00970 
00971     if (ll_type != ADDR_NONE ) {
00972         ncache_entry = ipv6_neighbour_update_unsolicited(ncache, redirect_addr, ll_type, ll_address);
00973         if (ncache_entry) {
00974             ncache_entry->from_redirect = true;
00975         }
00976     }
00977 
00978     if (to_router) {
00979         if (!ncache_entry) {
00980             ncache_entry = ipv6_neighbour_lookup(ncache, redirect_addr);
00981         }
00982 
00983         if (ncache_entry) {
00984             ncache_entry->is_router = true;
00985         }
00986     }
00987 
00988     tr_debug("Redirection added");
00989     tr_debug("Iface %d destination: %s", interface_id, trace_ipv6(dest_addr));
00990     tr_debug("Old next hop: %s", trace_ipv6(sender_addr));
00991     tr_debug("New next hop: %s", trace_ipv6(redirect_addr));
00992 }
00993 #endif
00994 
00995 static void ipv6_destination_release(ipv6_destination_t *dest)
00996 {
00997     if (--dest->refcount == 0) {
00998         ns_dyn_mem_free(dest);
00999     }
01000 }
01001 
01002 static void ipv6_destination_cache_gc_periodic(void)
01003 {
01004     uint_fast16_t gc_count = 0;
01005     ns_list_foreach_safe(ipv6_destination_t, entry, &ipv6_destination_cache) {
01006         if (entry->lifetime) {
01007             entry->lifetime--;
01008         }
01009         gc_count++;
01010 #ifndef NO_IPV6_PMTUD
01011         /* Purge old PMTU values */
01012         if (entry->pmtu_lifetime) {
01013             if (entry->pmtu_lifetime <= DCACHE_GC_PERIOD) {
01014                 tr_info("Resetting PMTU for: %s", trace_ipv6(entry->destination));
01015                 entry->pmtu_lifetime = 0;
01016                 uint16_t old_mtu = entry->pmtu;
01017                 if (entry->interface_id >= 0) {
01018                     entry->pmtu = ipv6_neighbour_cache_by_interface_id(entry->interface_id)->link_mtu;
01019                 } else {
01020                     entry->pmtu = 0xffff;
01021                 }
01022                 if (entry->pmtu != old_mtu) {
01023                 //   socket_pmtu_changed(entry->destination, entry->interface_id, old_mtu, entry->pmtu);
01024                 }
01025             } else {
01026                 entry->pmtu_lifetime -= DCACHE_GC_PERIOD;
01027             }
01028         }
01029 #endif
01030     }
01031 
01032     if (gc_count <= cache_long_term(true)) {
01033         return;
01034     }
01035 
01036     /* Cache is in most-recently-used-first order. GC strategy is to start from
01037      * the back, and reduce the size to "MAX_SHORT_TERM" every GC period,
01038      * deleting any entry. Timed-out entries will be deleted to keep it to
01039      * MAX_LONG_TERM.
01040      */
01041     ns_list_foreach_reverse_safe(ipv6_destination_t, entry, &ipv6_destination_cache) {
01042         if (entry->lifetime == 0 || gc_count > cache_short_term(true)) {
01043             ns_list_remove(&ipv6_destination_cache, entry);
01044             ipv6_destination_release(entry);
01045             if (--gc_count <= cache_long_term(true)) {
01046                 break;
01047             }
01048         }
01049     }
01050 
01051 }
01052 
01053 void ipv6_destination_cache_timer(uint8_t seconds)
01054 {
01055     dcache_gc_timer += seconds;
01056 
01057     if (dcache_gc_timer >= DCACHE_GC_PERIOD) {
01058         dcache_gc_timer -= DCACHE_GC_PERIOD;
01059         ipv6_destination_cache_gc_periodic();
01060         //ipv6_destination_cache_print(trace_debug_print);
01061         //ipv6_route_table_print(trace_debug_print);
01062     }
01063 }
01064 
01065 static const char *route_src_names[] = {
01066     [ROUTE_ANY]     = "?",
01067     [ROUTE_STATIC]  = "Static",
01068     [ROUTE_USER]    = "User",
01069     [ROUTE_LOOPBACK] = "Loopback",
01070     [ROUTE_RADV]    = "RAdv",
01071     [ROUTE_ARO]     = "ARO",
01072     [ROUTE_RPL_DAO] = "RPL DAO",
01073     [ROUTE_RPL_DAO_SR] = "RPL DAO SR",
01074     [ROUTE_RPL_SRH] = "RPL SRH",
01075     [ROUTE_RPL_DIO] = "RPL DIO",
01076     [ROUTE_RPL_ROOT] = "RPL Root",
01077     [ROUTE_RPL_INSTANCE] = "RPL Instance",
01078     [ROUTE_RPL_FWD_ERROR] = "RPL Fwd-Error",
01079     [ROUTE_MULTICAST] = "Multicast",
01080     [ROUTE_MPL]     = "MPL",
01081     [ROUTE_RIP]     = "RIP",
01082     [ROUTE_THREAD]  = "Thread",
01083     [ROUTE_THREAD_BORDER_ROUTER] = "Thread BR",
01084     [ROUTE_THREAD_PROXIED_HOST] = "Thread Proxy",
01085     [ROUTE_REDIRECT] = "Redirect",
01086 };
01087 
01088 /* Which types of routes get probed as per RFC 4191 */
01089 /* (Others are assumed to be always reachable) */
01090 static const bool ipv6_route_probing[ROUTE_MAX] = {
01091     [ROUTE_RADV] = true,
01092     [ROUTE_RPL_DAO] = true,
01093     [ROUTE_RPL_DIO] = true,
01094     [ROUTE_RPL_ROOT] = true,
01095     [ROUTE_RPL_INSTANCE] = true,
01096 };
01097 
01098 /* Which route types get minimum link MTU by default */
01099 /* Makes life easier for tunnel-based systems like RPL */
01100 static const bool ipv6_route_min_mtu[ROUTE_MAX] = {
01101     [ROUTE_RPL_DAO] = true,
01102     [ROUTE_RPL_DAO_SR] = true,
01103     [ROUTE_RPL_DIO] = true,
01104     [ROUTE_RPL_ROOT] = true,
01105     [ROUTE_RPL_INSTANCE] = true,
01106     [ROUTE_MPL] = true,
01107 };
01108 
01109 // Remember when a route source has deleted an entry - allows buffers still in
01110 // event queue to have their route info invalidated.
01111 static bool ipv6_route_source_invalidated[ROUTE_MAX];
01112 
01113 static ipv6_route_predicate_fn_t *ipv6_route_predicate[ROUTE_MAX];
01114 static ipv6_route_next_hop_fn_t *ipv6_route_next_hop_computation[ROUTE_MAX];
01115 
01116 void ipv6_route_table_set_predicate_fn(ipv6_route_src_t src, ipv6_route_predicate_fn_t fn)
01117 {
01118     ipv6_route_predicate[src] = fn;
01119 }
01120 
01121 void ipv6_route_table_set_next_hop_fn(ipv6_route_src_t src, ipv6_route_next_hop_fn_t fn)
01122 {
01123     ipv6_route_next_hop_computation[src] = fn;
01124 }
01125 
01126 static void ipv6_route_print(const ipv6_route_t *route, route_print_fn_t *print_fn)
01127 {
01128     // Route prefix is variable-length, so need to zero pad for ip6tos
01129     uint8_t addr[16] = { 0 };
01130     bitcopy(addr, route->prefix, route->prefix_len);
01131     ROUTE_PRINT_ADDR_STR_BUFFER_INIT(addr_str);
01132     if (route->lifetime != 0xFFFFFFFF) {
01133         print_fn(" %24s/%-3u if:%u src:'%s' id:%d lifetime:%"PRIu32,
01134                ROUTE_PRINT_ADDR_STR_FORMAT(addr_str, addr), route->prefix_len, route->info.interface_id,
01135                route_src_names[route->info.source], route->info.source_id, route->lifetime
01136               );
01137     } else {
01138         print_fn(" %24s/%-3u if:%u src:'%s' id:%d lifetime:infinite",
01139                ROUTE_PRINT_ADDR_STR_FORMAT(addr_str, addr), route->prefix_len, route->info.interface_id,
01140                route_src_names[route->info.source], route->info.source_id
01141               );
01142     }
01143     if (route->on_link) {
01144         print_fn("     On-link (met %d)", total_metric(route));
01145     } else {
01146         print_fn("     next-hop %s (met %d)", ROUTE_PRINT_ADDR_STR_FORMAT(addr_str, route->info.next_hop_addr), total_metric(route));
01147     }
01148 }
01149 
01150 void ipv6_route_table_print(route_print_fn_t *print_fn)
01151 {
01152     print_fn("Routing table:");
01153     ns_list_foreach(ipv6_route_t, r, &ipv6_routing_table) {
01154         ipv6_route_print(r, print_fn);
01155     }
01156 }
01157 
01158 /*
01159  * This function returns total effective metric, which is a combination
01160  * of 1) route metric, and 2) interface metric. Can be extended to include
01161  * protocol metric as well in the future.
01162  */
01163 static uint16_t total_metric(const ipv6_route_t *route)
01164 {
01165     ipv6_neighbour_cache_t *cache;
01166     uint16_t metric;
01167 
01168     metric = route->metric;
01169     cache = ipv6_neighbour_cache_by_interface_id(route->info.interface_id);
01170 
01171     if (cache) {
01172         metric += cache->route_if_info.metric;
01173     }
01174 
01175     return metric;
01176 }
01177 
01178 #ifdef FEA_TRACE_SUPPORT
01179 void trace_debug_print(const char *fmt, ...)
01180 {
01181     va_list ap;
01182     va_start(ap, fmt);
01183     vtracef(TRACE_LEVEL_DEBUG, TRACE_GROUP, fmt, ap);
01184     va_end(ap);
01185 }
01186 #endif
01187 
01188 static void ipv6_route_entry_remove(ipv6_route_t *route)
01189 {
01190     tr_debug("Deleted route:");
01191 #ifdef FEA_TRACE_SUPPORT
01192     ipv6_route_print(route, trace_debug_print);
01193 #endif
01194     if (protocol_core_buffers_in_event_queue > 0) {
01195         // Alert any buffers in the queue already routed by this source
01196         ipv6_route_source_invalidated[route->info.source] = true;
01197     }
01198     ns_list_remove(&ipv6_routing_table, route);
01199     ns_dyn_mem_free(route);
01200 }
01201 
01202 static bool ipv6_route_same_router(const ipv6_route_t *a, const ipv6_route_t *b)
01203 {
01204     if (a == b) {
01205         return true;
01206     }
01207     return !a->on_link && !b->on_link &&
01208            a->info.interface_id == b->info.interface_id &&
01209            addr_ipv6_equal(a->info.next_hop_addr, b->info.next_hop_addr);
01210 }
01211 
01212 static void ipv6_route_probe(ipv6_route_t *route)
01213 {
01214     ipv6_neighbour_cache_t *ncache = ipv6_neighbour_cache_by_interface_id(route->info.interface_id);
01215     if (!ncache || !ncache->send_nud_probes || route->probe_timer) {
01216         return;
01217     }
01218 
01219     ipv6_neighbour_t *n = ipv6_neighbour_lookup_or_create(ncache, route->info.next_hop_addr);
01220     if (!n) {
01221         return;
01222     }
01223     ipv6_interface_resolve_send_ns(ncache, n, true, 0);
01224 
01225     /* We need to limit to once per minute *per router* - so set the hold-off
01226      * timer for *all* routing entries to this router
01227      */
01228     ns_list_foreach(ipv6_route_t, r, &ipv6_routing_table) {
01229         if (ipv6_route_same_router(r, route)) {
01230             r->probe_timer = 60;
01231             r->probe = false;
01232         }
01233     }
01234 }
01235 
01236 /* Return true is a is better than b */
01237 static bool ipv6_route_is_better(const ipv6_route_t *a, const ipv6_route_t *b)
01238 {
01239     /* Prefer longer prefix */
01240     if (a->prefix_len < b->prefix_len) {
01241         return false;
01242     }
01243 
01244     if (a->prefix_len > b->prefix_len) {
01245         return true;
01246     }
01247 
01248     /* Prefer on-link */
01249     if (b->on_link && !a->on_link) {
01250         return false;
01251     }
01252 
01253     if (a->on_link && !b->on_link) {
01254         return true;
01255     }
01256 
01257     /* If prefixes exactly equal, tiebreak by metric */
01258     return total_metric(a) < total_metric(b);
01259 }
01260 
01261 /* Find the "best" route regardless of reachability, but respecting the skip flag and predicates */
01262 static ipv6_route_t *ipv6_route_find_best(const uint8_t *addr, int8_t interface_id, ipv6_route_predicate_fn_t *predicate)
01263 {
01264     ipv6_route_t *best = NULL;
01265     ns_list_foreach(ipv6_route_t, route, &ipv6_routing_table) {
01266         /* We mustn't be skipping this route */
01267         if (route->search_skip) {
01268             continue;
01269         }
01270 
01271         /* Interface must match, if caller specified */
01272         if (interface_id != -1 && interface_id != route->info.interface_id) {
01273             continue;
01274         }
01275 
01276         /* Prefix must match */
01277         if (!bitsequal(addr, route->prefix, route->prefix_len)) {
01278             continue;
01279         }
01280 
01281         /* Check the predicate for the route itself. This allows,
01282          * RPL "root" routes (the instance defaults) to be ignored in normal
01283          * lookup. Note that for caching to work properly, we require
01284          * the route predicate to produce "constant" results.
01285          */
01286         bool valid = true;
01287         if (ipv6_route_predicate[route->info.source]) {
01288             valid = ipv6_route_predicate[route->info.source](&route->info, valid);
01289         }
01290 
01291         /* Then the supplied search-specific predicate can override */
01292         if (predicate) {
01293             valid = predicate(&route->info, valid);
01294         }
01295 
01296         /* If blocked by either predicate, skip */
01297         if (!valid) {
01298             continue;
01299         }
01300 
01301         if (!best || ipv6_route_is_better(route, best)) {
01302             best = route;
01303         }
01304     }
01305     return best;
01306 }
01307 
01308 ipv6_route_t *ipv6_route_choose_next_hop(const uint8_t *dest, int8_t interface_id, ipv6_route_predicate_fn_t *predicate)
01309 {
01310     ipv6_route_t *best = NULL;
01311     bool reachable = false;
01312     bool need_to_probe = false;
01313 
01314     ns_list_foreach(ipv6_route_t, route, &ipv6_routing_table) {
01315         route->search_skip = false;
01316     }
01317 
01318     /* Search algorithm from RFC 4191, S3.2:
01319      *
01320      * When a type C host does next-hop determination and consults its
01321      * Routing Table for an off-link destination, it searches its routing
01322      * table to find the route with the longest prefix that matches the
01323      * destination, using route preference values as a tie-breaker if
01324      * multiple matching routes have the same prefix length.  If the best
01325      * route points to a non-reachable router, this router is remembered for
01326      * the algorithm described in Section 3.5 below, and the next best route
01327      * is consulted.  This check is repeated until a matching route is found
01328      * that points to a reachable router, or no matching routes remain.
01329      *
01330      * Note that rather than having a separate on-link Prefix List, we have
01331      * on-link entries. These take precedence over default routes (by their
01332      * non-0 length), but not necessarily over more-specific routes. Therefore
01333      * it is possible that we consider a few non-reachable routers first, then
01334      * fall back to on-link. This behaviour may or may not be desired, depending
01335      * on the scenario. If not desired, the router entries should have their
01336      * "probing" flag set to false, so they always take precedence over
01337      * the on-link entry.
01338      *
01339      * There is currently no mechanism for an on-link entry to always take
01340      * precedence over a more-specific route, which is what would happen if
01341      * we really did have a separate Prefix List and Routing Table. One
01342      * possibility would be a special precedence flag.
01343      */
01344     for (;;) {
01345         ipv6_route_t *route = ipv6_route_find_best(dest, interface_id, predicate);
01346         if (!route) {
01347             break;
01348         }
01349 
01350         if (route->on_link) {
01351             reachable = true;
01352         } else {
01353             /* Some routes (eg RPL SR) compute next hop on demand */
01354             if (ipv6_route_next_hop_computation[route->info.source]) {
01355                 if (!ipv6_route_next_hop_computation[route->info.source](dest, &route->info)) {
01356                     route->search_skip = true;
01357                     continue;
01358                 }
01359             }
01360 
01361             ipv6_neighbour_cache_t *ncache = ipv6_neighbour_cache_by_interface_id(route->info.interface_id);
01362             if (!ncache) {
01363                 tr_warn("Invalid interface ID in routing table!");
01364                 route->search_skip = true;
01365                 continue;
01366             }
01367 
01368             if (ncache->send_nud_probes && ipv6_route_probing[route->info.source]) {
01369                 /* Going via a router - check reachability, as per RFC 4191.
01370                  * This only applies for certain routes (currently those from RAs) */
01371                 reachable = ipv6_neighbour_addr_is_probably_reachable(ncache, route->info.next_hop_addr);
01372             } else {
01373                 /* Can't probe, so have to assume router is reachable */
01374                 reachable = true;
01375             }
01376         }
01377 
01378         if (reachable) {
01379             /* If router is reachable, we'll take it now */
01380             best = route;
01381             break;
01382         } else {
01383             /* Otherwise, note it, and look for other less-good reachable ones */
01384             route->search_skip = true;
01385 
01386             /* As we would have used it, probe to check for reachability */
01387             route->probe = need_to_probe = true;
01388 
01389             if (!best) {
01390                 best = route;
01391             }
01392             continue;
01393         }
01394     }
01395 
01396     /* This is a bit icky - data structures are routes, but we need to probe
01397      * routers - a many->1 mapping. Probe flag is set on all routes we skipped;
01398      * but we don't want to probe the router we actually chose.
01399      */
01400     if (need_to_probe) {
01401         ns_list_foreach(ipv6_route_t, r, &ipv6_routing_table) {
01402             if (!r->probe) {
01403                 continue;
01404             }
01405             r->probe = false;
01406 
01407             /* Note that best must be set if need_to_probe is */
01408             if (!ipv6_route_same_router(r, best) && ipv6_route_is_better(r, best)) {
01409                 ipv6_route_probe(r);
01410             }
01411         }
01412     }
01413 
01414     if (best && !reachable) {
01415         /* We've chosen a non-reachable router; this means no routers were
01416          * reachable. Move it to the bottom of the list, so that next time
01417          * we do this, we try (and hence probe) another non-reachable router,
01418          * otherwise we'll never make progress. This satisfies the
01419          * round-robin requirement in RFC 4861 6.3.6.2, enhanced for RFC 4191.
01420          */
01421         ns_list_remove(&ipv6_routing_table, best);
01422         ns_list_add_to_end(&ipv6_routing_table, best);
01423     }
01424 
01425     return best;
01426 }
01427 
01428 ipv6_route_t *ipv6_route_lookup_with_info(const uint8_t *prefix, uint8_t prefix_len, int8_t interface_id, const uint8_t *next_hop, ipv6_route_src_t source, void *info, int_fast16_t src_id)
01429 {
01430     ns_list_foreach(ipv6_route_t, r, &ipv6_routing_table) {
01431         if (interface_id == r->info.interface_id && prefix_len == r->prefix_len && bitsequal(prefix, r->prefix, prefix_len)) {
01432             if (source != ROUTE_ANY) {
01433                 if (source != r->info.source) {
01434                     continue;
01435                 }
01436                 if (info && info != r->info.info) {
01437                     continue;
01438                 }
01439                 if (src_id != -1 && src_id != r->info.source_id) {
01440                     continue;
01441                 }
01442                 if (info && ipv6_route_next_hop_computation[source]) {
01443                     /* No need to match the actual next hop - we assume info distinguishes */
01444                     return r;
01445                 }
01446             }
01447 
01448             /* "next_hop" being NULL means on-link; this is a flag in the route entry, and r->next_hop can't be NULL */
01449             if ((next_hop && r->on_link) || (!next_hop && !r->on_link)) {
01450                 continue;
01451             }
01452 
01453             if (next_hop && !r->on_link && !addr_ipv6_equal(next_hop, r->info.next_hop_addr)) {
01454                 continue;
01455             }
01456 
01457             return r;
01458         }
01459     }
01460 
01461     return NULL;
01462 }
01463 
01464 #define PREF_TO_METRIC(pref) (128 - 64 * (pref))
01465 
01466 uint8_t ipv6_route_pref_to_metric(int_fast8_t pref)
01467 {
01468     if (pref <-1 || pref > +1) {
01469         pref = 0;
01470     }
01471     return PREF_TO_METRIC(pref);
01472 }
01473 
01474 ipv6_route_t *ipv6_route_add(const uint8_t *prefix, uint8_t prefix_len, int8_t interface_id, const uint8_t *next_hop, ipv6_route_src_t source, uint32_t lifetime, int_fast8_t pref)
01475 {
01476     return ipv6_route_add_with_info(prefix, prefix_len, interface_id, next_hop, source, NULL, 0, lifetime, pref);
01477 }
01478 
01479 ipv6_route_t *ipv6_route_add_with_info(const uint8_t *prefix, uint8_t prefix_len, int8_t interface_id, const uint8_t *next_hop, ipv6_route_src_t source, void *info, uint8_t source_id, uint32_t lifetime, int_fast8_t pref)
01480 {
01481     /* Only support -1, 0 and +1 prefs, as per RFC 4191 */
01482     if (pref < -1 || pref > +1) {
01483         return NULL;
01484     }
01485 
01486     return ipv6_route_add_metric(prefix, prefix_len, interface_id, next_hop, source, info,  source_id, lifetime, PREF_TO_METRIC(pref));
01487 }
01488 
01489 ipv6_route_t *ipv6_route_add_metric(const uint8_t *prefix, uint8_t prefix_len, int8_t interface_id, const uint8_t *next_hop, ipv6_route_src_t source, void *info, uint8_t source_id, uint32_t lifetime, uint8_t metric)
01490 {
01491     ipv6_route_t *route = NULL;
01492     enum { UNCHANGED, UPDATED, NEW } changed_info = UNCHANGED;
01493 
01494     // Maybe don't need this after all? We'll just assume that the next_hop is on-link
01495     // Thread certainly wants to use ULAs...
01496 #if 0
01497     if (next_hop) {
01498         /* Currently we require that all routes must be to link-local addresses. */
01499         /* This simplifies all sorts of things - particularly that we can assume link-local addresses to be on-link. */
01500         /* It is needed to make Redirects and probes work too. */
01501         if (!addr_is_ipv6_link_local(next_hop)) {
01502             return NULL;
01503         }
01504     }
01505 #endif
01506 
01507 
01508     /* Check for matching info, in which case it's an update */
01509     route = ipv6_route_lookup_with_info(prefix, prefix_len, interface_id, next_hop, source, info, source_id);
01510 
01511     /* 0 lifetime is a deletion request (common to all protocols) */
01512     if (lifetime == 0) {
01513         if (route) {
01514             tr_debug("Zero route lifetime");
01515             ipv6_route_entry_remove(route);
01516         }
01517         return NULL;
01518     }
01519 
01520     uint8_t max_entries = ipv6_route_table_get_max_entries(interface_id, source);
01521     if (max_entries > 0) {
01522         uint8_t entries = ipv6_route_table_count_source(interface_id, source);
01523         if (entries > max_entries) {
01524             ipv6_route_table_remove_last_one_from_source(interface_id, source);
01525         }
01526     }
01527 
01528     if (!route) { /* new route */
01529         uint_fast8_t prefix_bytes = (prefix_len + 7u) / 8u;
01530         route = ns_dyn_mem_alloc(sizeof(ipv6_route_t) + prefix_bytes);
01531         if (!route) {
01532             return NULL;
01533         }
01534         memset(route->prefix, 0, prefix_bytes);
01535         bitcopy(route->prefix, prefix, prefix_len);
01536         route->prefix_len = prefix_len;
01537         route->search_skip = false;
01538         route->probe = false;
01539         route->probe_timer = 0;
01540         route->lifetime = lifetime;
01541         route->metric = metric;
01542         route->info.source = source;
01543         route->info.info = info;
01544         route->info.source_id = source_id;
01545         route->info.interface_id = interface_id;
01546         route->info.pmtu = ipv6_route_min_mtu[source] ? IPV6_MIN_LINK_MTU : 0xFFFF;
01547         if (next_hop) {
01548             route->on_link = false;
01549             memcpy(route->info.next_hop_addr, next_hop, 16);
01550         } else {
01551             route->on_link = true;
01552             memset(route->info.next_hop_addr, 0, 16);
01553         }
01554 
01555         /* See ipv6_route_probe - all routing entries to the same router
01556          * want to share the same hold-off time, so search and copy.
01557          */
01558         if (next_hop) {
01559             ns_list_foreach(ipv6_route_t, r, &ipv6_routing_table) {
01560                 if (ipv6_route_same_router(r, route)) {
01561                     route->probe_timer = r->probe_timer;
01562                     break;
01563                 }
01564             }
01565         }
01566 
01567         /* Routing table will be resorted during use, thanks to probing. */
01568         /* Doesn't matter much where they start off, but put them at the */
01569         /* beginning so new routes tend to get tried first. */
01570         ns_list_add_to_start(&ipv6_routing_table, route);
01571         changed_info = NEW;
01572     } else { /* updating a route - only lifetime and metric can be changing */
01573         route->lifetime = lifetime;
01574         if (metric != route->metric) {
01575             route->metric = metric;
01576             changed_info = UPDATED;
01577         }
01578     }
01579 
01580     if (changed_info != UNCHANGED) {
01581         tr_debug("%s route:", changed_info == NEW ? "Added" : "Updated");
01582 #ifdef FEA_TRACE_SUPPORT
01583         ipv6_route_print(route, trace_debug_print);
01584 #endif
01585     }
01586 
01587     return route;
01588 }
01589 
01590 int_fast8_t ipv6_route_delete(const uint8_t *prefix, uint8_t prefix_len, int8_t interface_id, const uint8_t *next_hop, ipv6_route_src_t source)
01591 {
01592     return ipv6_route_delete_with_info(prefix, prefix_len, interface_id, next_hop, source, NULL, 0);
01593 }
01594 
01595 int_fast8_t ipv6_route_delete_with_info(const uint8_t *prefix, uint8_t prefix_len, int8_t interface_id, const uint8_t *next_hop, ipv6_route_src_t source, void *info, int_fast16_t source_id)
01596 {
01597     ipv6_route_t *route = ipv6_route_lookup_with_info(prefix, prefix_len, interface_id, next_hop, source, info, source_id);
01598     if (!route) {
01599         return -1;
01600     }
01601 
01602     ipv6_route_entry_remove(route);
01603     return 0;
01604 }
01605 
01606 void ipv6_route_table_remove_interface(int8_t interface_id)
01607 {
01608     ns_list_foreach_safe(ipv6_route_t, r, &ipv6_routing_table) {
01609         if (interface_id == r->info.interface_id) {
01610             ipv6_route_entry_remove(r);
01611         }
01612     }
01613 }
01614 
01615 static void ipv6_route_table_remove_router(int8_t interface_id, const uint8_t *addr, ipv6_route_src_t source)
01616 {
01617     ns_list_foreach_safe(ipv6_route_t, r, &ipv6_routing_table) {
01618         if (interface_id == r->info.interface_id && r->info.source == source && !r->on_link && addr_ipv6_equal(addr, r->info.next_hop_addr)) {
01619             ipv6_route_entry_remove(r);
01620         }
01621     }
01622 }
01623 
01624 /* Somewhat specialised - allow on-the-fly modification of metrics. Masking
01625  * allows for top "preference" bits to be preserved.
01626  */
01627 void ipv6_route_table_modify_router_metric(int8_t interface_id, const uint8_t *addr, ipv6_route_src_t source, uint8_t keep, uint8_t toggle)
01628 {
01629     ns_list_foreach(ipv6_route_t, r, &ipv6_routing_table) {
01630         if (interface_id == r->info.interface_id && r->info.source == source && !r->on_link && addr_ipv6_equal(addr, r->info.next_hop_addr)) {
01631             r->metric = (r->metric & keep) ^ toggle;
01632         }
01633     }
01634 
01635 }
01636 
01637 void ipv6_route_table_remove_info(int8_t interface_id, ipv6_route_src_t source, void *info)
01638 {
01639     ns_list_foreach_safe(ipv6_route_t, r, &ipv6_routing_table) {
01640         if ((interface_id == -1 || interface_id == r->info.interface_id) && r->info.source == source && (info == NULL || r->info.info == info)) {
01641             ipv6_route_entry_remove(r);
01642         }
01643     }
01644 }
01645 
01646 static uint8_t ipv6_route_table_count_source(int8_t interface_id, ipv6_route_src_t source)
01647 {
01648     uint8_t count = 0;
01649     ns_list_foreach(ipv6_route_t, r, &ipv6_routing_table) {
01650         if (interface_id == r->info.interface_id && r->info.source == source) {
01651             count++;
01652             if (count == 0xff) {
01653                 break;
01654             }
01655         }
01656     }
01657     return count;
01658 }
01659 
01660 static void ipv6_route_table_remove_last_one_from_source(int8_t interface_id, ipv6_route_src_t source)
01661 {
01662     // Removes last i.e. oldest entry */
01663     ns_list_foreach_reverse(ipv6_route_t, r, &ipv6_routing_table) {
01664         if (interface_id == r->info.interface_id && r->info.source == source) {
01665             ipv6_route_entry_remove(r);
01666             break;
01667         }
01668     }
01669 }
01670 
01671 
01672 void ipv6_route_table_ttl_update(uint16_t seconds)
01673 {
01674     ns_list_foreach_safe(ipv6_route_t, r, &ipv6_routing_table) {
01675         if (r->probe_timer) {
01676             if (r->probe_timer > seconds) {
01677                 r->probe_timer -= seconds;
01678             } else {
01679                 r->probe_timer = 0;
01680             }
01681         }
01682 
01683         if (r->lifetime == 0xFFFFFFFF) {
01684             continue;
01685         }
01686 
01687         if (r->lifetime > seconds) {
01688             r->lifetime -= seconds;
01689             continue;
01690         }
01691 
01692         tr_debug("Route expired");
01693         ipv6_route_entry_remove(r);
01694     }
01695 }
01696 
01697 void ipv6_route_table_set_max_entries(int8_t interface_id, ipv6_route_src_t source, uint8_t max_entries)
01698 {
01699     ipv6_neighbour_cache_t *ncache = ipv6_neighbour_cache_by_interface_id(interface_id);
01700 
01701     if (ncache) {
01702         ncache->route_if_info.sources[source] = max_entries;
01703     }
01704 }
01705 
01706 static uint8_t ipv6_route_table_get_max_entries(int8_t interface_id, ipv6_route_src_t source)
01707 {
01708     ipv6_neighbour_cache_t *ncache = ipv6_neighbour_cache_by_interface_id(interface_id);
01709 
01710     if (ncache) {
01711         return ncache->route_if_info.sources[source];
01712     }
01713 
01714     return 0;
01715 }
01716 
01717 bool ipv6_route_table_source_was_invalidated(ipv6_route_src_t src)
01718 {
01719     return ipv6_route_source_invalidated[src];
01720 }
01721 
01722 // Called when event queue is empty - no pending buffers so can clear invalidation flags.
01723 void ipv6_route_table_source_invalidated_reset(void)
01724 {
01725     memset(ipv6_route_source_invalidated, false, sizeof ipv6_route_source_invalidated);
01726 }