diff options
Diffstat (limited to 'thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/core/ipv6/nd6.c')
| -rw-r--r-- | thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/core/ipv6/nd6.c | 2108 |
1 files changed, 2108 insertions, 0 deletions
diff --git a/thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/core/ipv6/nd6.c b/thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/core/ipv6/nd6.c new file mode 100644 index 0000000..4c07c87 --- /dev/null +++ b/thirdparty/nRF5_SDK_15.0.0_a53641a/external/lwip/src/core/ipv6/nd6.c @@ -0,0 +1,2108 @@ +/** + * @file + * + * Neighbor discovery and stateless address autoconfiguration for IPv6. + * Aims to be compliant with RFC 4861 (Neighbor discovery) and RFC 4862 + * (Address autoconfiguration). + */ + +/* + * Copyright (c) 2010 Inico Technologies Ltd. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without modification, + * are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT + * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT + * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING + * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY + * OF SUCH DAMAGE. + * + * This file is part of the lwIP TCP/IP stack. + * + * Author: Ivan Delamer <delamer@inicotech.com> + * + * + * Please coordinate changes and requests with Ivan Delamer + * <delamer@inicotech.com> + */ + +#include "lwip/opt.h" + +#if LWIP_IPV6 /* don't build if not configured for use in lwipopts.h */ + +#include "lwip/nd6.h" +#include "lwip/priv/nd6_priv.h" +#include "lwip/prot/nd6.h" +#include "lwip/prot/icmp6.h" +#include "lwip/pbuf.h" +#include "lwip/mem.h" +#include "lwip/memp.h" +#include "lwip/ip6.h" +#include "lwip/ip6_addr.h" +#include "lwip/inet_chksum.h" +#include "lwip/netif.h" +#include "lwip/icmp6.h" +#include "lwip/mld6.h" +#include "lwip/ip.h" +#include "lwip/stats.h" +#include "lwip/dns.h" + +#include <string.h> + +#ifdef LWIP_HOOK_FILENAME +#include LWIP_HOOK_FILENAME +#endif + +#if LWIP_IPV6_DUP_DETECT_ATTEMPTS > IP6_ADDR_TENTATIVE_COUNT_MASK +#error LWIP_IPV6_DUP_DETECT_ATTEMPTS > IP6_ADDR_TENTATIVE_COUNT_MASK +#endif + +/* Router tables. */ +struct nd6_neighbor_cache_entry neighbor_cache[LWIP_ND6_NUM_NEIGHBORS]; +struct nd6_destination_cache_entry destination_cache[LWIP_ND6_NUM_DESTINATIONS]; +struct nd6_prefix_list_entry prefix_list[LWIP_ND6_NUM_PREFIXES]; +struct nd6_router_list_entry default_router_list[LWIP_ND6_NUM_ROUTERS]; + +/* Default values, can be updated by a RA message. */ +u32_t reachable_time = LWIP_ND6_REACHABLE_TIME; +u32_t retrans_timer = LWIP_ND6_RETRANS_TIMER; /* @todo implement this value in timer */ + +/* Index for cache entries. */ +static u8_t nd6_cached_neighbor_index; +static u8_t nd6_cached_destination_index; + +/* Multicast address holder. */ +static ip6_addr_t multicast_address; + +/* Static buffer to parse RA packet options (size of a prefix option, biggest option) */ +static u8_t nd6_ra_buffer[sizeof(struct prefix_option)]; + +/* Forward declarations. */ +static s8_t nd6_find_neighbor_cache_entry(const ip6_addr_t *ip6addr); +static s8_t nd6_new_neighbor_cache_entry(void); +static void nd6_free_neighbor_cache_entry(s8_t i); +static s8_t nd6_find_destination_cache_entry(const ip6_addr_t *ip6addr); +static s8_t nd6_new_destination_cache_entry(void); +static s8_t nd6_is_prefix_in_netif(const ip6_addr_t *ip6addr, struct netif *netif); +static s8_t nd6_select_router(const ip6_addr_t *ip6addr, struct netif *netif); +static s8_t nd6_get_router(const ip6_addr_t *router_addr, struct netif *netif); +static s8_t nd6_new_router(const ip6_addr_t *router_addr, struct netif *netif); +static s8_t nd6_get_onlink_prefix(ip6_addr_t *prefix, struct netif *netif); +static s8_t nd6_new_onlink_prefix(ip6_addr_t *prefix, struct netif *netif); +static s8_t nd6_get_next_hop_entry(const ip6_addr_t *ip6addr, struct netif *netif); +static err_t nd6_queue_packet(s8_t neighbor_index, struct pbuf *q); + +#define ND6_SEND_FLAG_MULTICAST_DEST 0x01 +#define ND6_SEND_FLAG_ALLNODES_DEST 0x02 +static void nd6_send_ns(struct netif *netif, const ip6_addr_t *target_addr, u8_t flags); +static void nd6_send_na(struct netif *netif, const ip6_addr_t *target_addr, u8_t flags); +static void nd6_send_neighbor_cache_probe(struct nd6_neighbor_cache_entry *entry, u8_t flags); +#if LWIP_IPV6_SEND_ROUTER_SOLICIT +static err_t nd6_send_rs(struct netif *netif); +#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */ + +#if LWIP_ND6_QUEUEING +static void nd6_free_q(struct nd6_q_entry *q); +#else /* LWIP_ND6_QUEUEING */ +#define nd6_free_q(q) pbuf_free(q) +#endif /* LWIP_ND6_QUEUEING */ +static void nd6_send_q(s8_t i); + + +/** + * Process an incoming neighbor discovery message + * + * @param p the nd packet, p->payload pointing to the icmpv6 header + * @param inp the netif on which this packet was received + */ +void +nd6_input(struct pbuf *p, struct netif *inp) +{ + u8_t msg_type; + s8_t i; + + ND6_STATS_INC(nd6.recv); + + msg_type = *((u8_t *)p->payload); + switch (msg_type) { + case ICMP6_TYPE_NA: /* Neighbor Advertisement. */ + { + struct na_header *na_hdr; + struct lladdr_option *lladdr_opt; + + /* Check that na header fits in packet. */ + if (p->len < (sizeof(struct na_header))) { + /* @todo debug message */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + + na_hdr = (struct na_header *)p->payload; + + /* Unsolicited NA?*/ + if (ip6_addr_ismulticast(ip6_current_dest_addr())) { + ip6_addr_t target_address; + + /* This is an unsolicited NA. + * link-layer changed? + * part of DAD mechanism? */ + + /* Create an aligned copy. */ + ip6_addr_set(&target_address, &(na_hdr->target_address)); + +#if LWIP_IPV6_DUP_DETECT_ATTEMPTS + /* If the target address matches this netif, it is a DAD response. */ + for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) { + if (!ip6_addr_isinvalid(netif_ip6_addr_state(inp, i)) && + ip6_addr_cmp(&target_address, netif_ip6_addr(inp, i))) { + /* We are using a duplicate address. */ + netif_ip6_addr_set_state(inp, i, IP6_ADDR_INVALID); + +#if LWIP_IPV6_AUTOCONFIG + /* Check to see if this address was autoconfigured. */ + if (!ip6_addr_islinklocal(&target_address)) { + i = nd6_get_onlink_prefix(&target_address, inp); + if (i >= 0) { + /* Mark this prefix as duplicate, so that we don't use it + * to generate this address again. */ + prefix_list[i].flags |= ND6_PREFIX_AUTOCONFIG_ADDRESS_DUPLICATE; + } + } +#endif /* LWIP_IPV6_AUTOCONFIG */ + + pbuf_free(p); + return; + } + } +#endif /* LWIP_IPV6_DUP_DETECT_ATTEMPTS */ + + /* Check that link-layer address option also fits in packet. */ + if (p->len < (sizeof(struct na_header) + 2)) { + /* @todo debug message */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + + lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct na_header)); + + if (p->len < (sizeof(struct na_header) + (lladdr_opt->length << 3))) { + /* @todo debug message */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + + /* This is an unsolicited NA, most likely there was a LLADDR change. */ + i = nd6_find_neighbor_cache_entry(&target_address); + if (i >= 0) { + if (na_hdr->flags & ND6_FLAG_OVERRIDE) { + MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len); + } + } + } else { + ip6_addr_t target_address; + + /* This is a solicited NA. + * neighbor address resolution response? + * neighbor unreachability detection response? */ + + /* Create an aligned copy. */ + ip6_addr_set(&target_address, &(na_hdr->target_address)); + + /* Find the cache entry corresponding to this na. */ + i = nd6_find_neighbor_cache_entry(&target_address); + if (i < 0) { + /* We no longer care about this target address. drop it. */ + pbuf_free(p); + return; + } + + /* Update cache entry. */ + if ((na_hdr->flags & ND6_FLAG_OVERRIDE) || + (neighbor_cache[i].state == ND6_INCOMPLETE)) { + /* Check that link-layer address option also fits in packet. */ + if (p->len < (sizeof(struct na_header) + 2)) { + /* @todo debug message */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + + lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct na_header)); + + if (p->len < (sizeof(struct na_header) + (lladdr_opt->length << 3))) { + /* @todo debug message */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + + MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len); + } + + neighbor_cache[i].netif = inp; + neighbor_cache[i].state = ND6_REACHABLE; + neighbor_cache[i].counter.reachable_time = reachable_time; + + /* Send queued packets, if any. */ + if (neighbor_cache[i].q != NULL) { + nd6_send_q(i); + } + } + + break; /* ICMP6_TYPE_NA */ + } + case ICMP6_TYPE_NS: /* Neighbor solicitation. */ + { + struct ns_header *ns_hdr; + struct lladdr_option *lladdr_opt; + u8_t accepted; + + /* Check that ns header fits in packet. */ + if (p->len < sizeof(struct ns_header)) { + /* @todo debug message */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + + ns_hdr = (struct ns_header *)p->payload; + + /* Check if there is a link-layer address provided. Only point to it if in this buffer. */ + if (p->len >= (sizeof(struct ns_header) + 2)) { + lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct ns_header)); + if (p->len < (sizeof(struct ns_header) + (lladdr_opt->length << 3))) { + lladdr_opt = NULL; + } + } else { + lladdr_opt = NULL; + } + + /* Check if the target address is configured on the receiving netif. */ + accepted = 0; + for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) { + if ((ip6_addr_isvalid(netif_ip6_addr_state(inp, i)) || + (ip6_addr_istentative(netif_ip6_addr_state(inp, i)) && + ip6_addr_isany(ip6_current_src_addr()))) && + ip6_addr_cmp(&(ns_hdr->target_address), netif_ip6_addr(inp, i))) { + accepted = 1; + break; + } + } + + /* NS not for us? */ + if (!accepted) { + pbuf_free(p); + return; + } + + /* Check for ANY address in src (DAD algorithm). */ + if (ip6_addr_isany(ip6_current_src_addr())) { + /* Sender is validating this address. */ + for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) { + if (!ip6_addr_isinvalid(netif_ip6_addr_state(inp, i)) && + ip6_addr_cmp(&(ns_hdr->target_address), netif_ip6_addr(inp, i))) { + /* Send a NA back so that the sender does not use this address. */ + nd6_send_na(inp, netif_ip6_addr(inp, i), ND6_FLAG_OVERRIDE | ND6_SEND_FLAG_ALLNODES_DEST); + if (ip6_addr_istentative(netif_ip6_addr_state(inp, i))) { + /* We shouldn't use this address either. */ + netif_ip6_addr_set_state(inp, i, IP6_ADDR_INVALID); + } + } + } + } else { + ip6_addr_t target_address; + + /* Sender is trying to resolve our address. */ + /* Verify that they included their own link-layer address. */ + if (lladdr_opt == NULL) { + /* Not a valid message. */ + pbuf_free(p); + ND6_STATS_INC(nd6.proterr); + ND6_STATS_INC(nd6.drop); + return; + } + + i = nd6_find_neighbor_cache_entry(ip6_current_src_addr()); + if (i>= 0) { + /* We already have a record for the solicitor. */ + if (neighbor_cache[i].state == ND6_INCOMPLETE) { + neighbor_cache[i].netif = inp; + MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len); + + /* Delay probe in case we get confirmation of reachability from upper layer (TCP). */ + neighbor_cache[i].state = ND6_DELAY; + neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL; + } + } else { + /* Add their IPv6 address and link-layer address to neighbor cache. + * We will need it at least to send a unicast NA message, but most + * likely we will also be communicating with this node soon. */ + i = nd6_new_neighbor_cache_entry(); + if (i < 0) { + /* We couldn't assign a cache entry for this neighbor. + * we won't be able to reply. drop it. */ + pbuf_free(p); + ND6_STATS_INC(nd6.memerr); + return; + } + neighbor_cache[i].netif = inp; + MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len); + ip6_addr_set(&(neighbor_cache[i].next_hop_address), ip6_current_src_addr()); + + /* Receiving a message does not prove reachability: only in one direction. + * Delay probe in case we get confirmation of reachability from upper layer (TCP). */ + neighbor_cache[i].state = ND6_DELAY; + neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL; + } + + /* Create an aligned copy. */ + ip6_addr_set(&target_address, &(ns_hdr->target_address)); + + /* Send back a NA for us. Allocate the reply pbuf. */ + nd6_send_na(inp, &target_address, ND6_FLAG_SOLICITED | ND6_FLAG_OVERRIDE); + } + + break; /* ICMP6_TYPE_NS */ + } + case ICMP6_TYPE_RA: /* Router Advertisement. */ + { + struct ra_header *ra_hdr; + u8_t *buffer; /* Used to copy options. */ + u16_t offset; +#if LWIP_ND6_RDNSS_MAX_DNS_SERVERS + /* There can by multiple RDNSS options per RA */ + u8_t rdnss_server_idx = 0; +#endif /* LWIP_ND6_RDNSS_MAX_DNS_SERVERS */ + + /* Check that RA header fits in packet. */ + if (p->len < sizeof(struct ra_header)) { + /* @todo debug message */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + + ra_hdr = (struct ra_header *)p->payload; + + /* If we are sending RS messages, stop. */ +#if LWIP_IPV6_SEND_ROUTER_SOLICIT + /* ensure at least one solicitation is sent */ + if ((inp->rs_count < LWIP_ND6_MAX_MULTICAST_SOLICIT) || + (nd6_send_rs(inp) == ERR_OK)) { + inp->rs_count = 0; + } +#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */ + + /* Get the matching default router entry. */ + i = nd6_get_router(ip6_current_src_addr(), inp); + if (i < 0) { + /* Create a new router entry. */ + i = nd6_new_router(ip6_current_src_addr(), inp); + } + + if (i < 0) { + /* Could not create a new router entry. */ + pbuf_free(p); + ND6_STATS_INC(nd6.memerr); + return; + } + + /* Re-set invalidation timer. */ + default_router_list[i].invalidation_timer = lwip_htons(ra_hdr->router_lifetime); + + /* Re-set default timer values. */ +#if LWIP_ND6_ALLOW_RA_UPDATES + if (ra_hdr->retrans_timer > 0) { + retrans_timer = lwip_htonl(ra_hdr->retrans_timer); + } + if (ra_hdr->reachable_time > 0) { + reachable_time = lwip_htonl(ra_hdr->reachable_time); + } +#endif /* LWIP_ND6_ALLOW_RA_UPDATES */ + + /* @todo set default hop limit... */ + /* ra_hdr->current_hop_limit;*/ + + /* Update flags in local entry (incl. preference). */ + default_router_list[i].flags = ra_hdr->flags; + + /* Offset to options. */ + offset = sizeof(struct ra_header); + + /* Process each option. */ + while ((p->tot_len - offset) > 0) { + if (p->len == p->tot_len) { + /* no need to copy from contiguous pbuf */ + buffer = &((u8_t*)p->payload)[offset]; + } else { + buffer = nd6_ra_buffer; + if (pbuf_copy_partial(p, buffer, sizeof(struct prefix_option), offset) != sizeof(struct prefix_option)) { + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + } + if (buffer[1] == 0) { + /* zero-length extension. drop packet */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + switch (buffer[0]) { + case ND6_OPTION_TYPE_SOURCE_LLADDR: + { + struct lladdr_option *lladdr_opt; + lladdr_opt = (struct lladdr_option *)buffer; + if ((default_router_list[i].neighbor_entry != NULL) && + (default_router_list[i].neighbor_entry->state == ND6_INCOMPLETE)) { + SMEMCPY(default_router_list[i].neighbor_entry->lladdr, lladdr_opt->addr, inp->hwaddr_len); + default_router_list[i].neighbor_entry->state = ND6_REACHABLE; + default_router_list[i].neighbor_entry->counter.reachable_time = reachable_time; + } + break; + } + case ND6_OPTION_TYPE_MTU: + { + struct mtu_option *mtu_opt; + mtu_opt = (struct mtu_option *)buffer; + if (lwip_htonl(mtu_opt->mtu) >= 1280) { +#if LWIP_ND6_ALLOW_RA_UPDATES + inp->mtu = (u16_t)lwip_htonl(mtu_opt->mtu); +#endif /* LWIP_ND6_ALLOW_RA_UPDATES */ + } + break; + } + case ND6_OPTION_TYPE_PREFIX_INFO: + { + struct prefix_option *prefix_opt; + prefix_opt = (struct prefix_option *)buffer; + + #if LWIP_BTLE_6LOWPAN + if ((prefix_opt->prefix_length == 64) && + !ip6_addr_islinklocal(&(prefix_opt->prefix))) { + #else //LWIP_BTLE_6LOWPAN + if ((prefix_opt->flags & ND6_PREFIX_FLAG_ON_LINK) && + (prefix_opt->prefix_length == 64) && + !ip6_addr_islinklocal(&(prefix_opt->prefix))) { + #endif //LWIP_BTLE_6LOWPAN + + /* Add to on-link prefix list. */ + s8_t prefix; + ip6_addr_t prefix_addr; + + /* Get a memory-aligned copy of the prefix. */ + ip6_addr_set(&prefix_addr, &(prefix_opt->prefix)); + + /* find cache entry for this prefix. */ + prefix = nd6_get_onlink_prefix(&prefix_addr, inp); + if (prefix < 0) { + /* Create a new cache entry. */ + prefix = nd6_new_onlink_prefix(&prefix_addr, inp); + } + if (prefix >= 0) { + prefix_list[prefix].invalidation_timer = lwip_htonl(prefix_opt->valid_lifetime); + +#if LWIP_IPV6_AUTOCONFIG + if (prefix_opt->flags & ND6_PREFIX_FLAG_AUTONOMOUS) { + /* Mark prefix as autonomous, so that address autoconfiguration can take place. + * Only OR flag, so that we don't over-write other flags (such as ADDRESS_DUPLICATE)*/ + prefix_list[prefix].flags |= ND6_PREFIX_AUTOCONFIG_AUTONOMOUS; + } +#endif /* LWIP_IPV6_AUTOCONFIG */ + } + } + + break; + } + case ND6_OPTION_TYPE_ROUTE_INFO: + /* @todo implement preferred routes. + struct route_option * route_opt; + route_opt = (struct route_option *)buffer;*/ + + break; +#if LWIP_ND6_RDNSS_MAX_DNS_SERVERS + case ND6_OPTION_TYPE_RDNSS: + { + u8_t num, n; + struct rdnss_option * rdnss_opt; + + rdnss_opt = (struct rdnss_option *)buffer; + num = (rdnss_opt->length - 1) / 2; + for (n = 0; (rdnss_server_idx < DNS_MAX_SERVERS) && (n < num); n++) { + ip_addr_t rdnss_address; + + /* Get a memory-aligned copy of the prefix. */ + ip_addr_copy_from_ip6(rdnss_address, rdnss_opt->rdnss_address[n]); + + if (htonl(rdnss_opt->lifetime) > 0) { + /* TODO implement Lifetime > 0 */ + dns_setserver(rdnss_server_idx++, &rdnss_address); + } else { + /* TODO implement DNS removal in dns.c */ + u8_t s; + for (s = 0; s < DNS_MAX_SERVERS; s++) { + const ip_addr_t *addr = dns_getserver(s); + if(ip_addr_cmp(addr, &rdnss_address)) { + dns_setserver(s, NULL); + } + } + } + } + break; + } +#endif /* LWIP_ND6_RDNSS_MAX_DNS_SERVERS */ + default: + /* Unrecognized option, abort. */ + ND6_STATS_INC(nd6.proterr); + break; + } + /* option length is checked earlier to be non-zero to make sure loop ends */ + offset += 8 * ((u16_t)buffer[1]); + } + + break; /* ICMP6_TYPE_RA */ + } + case ICMP6_TYPE_RD: /* Redirect */ + { + struct redirect_header *redir_hdr; + struct lladdr_option *lladdr_opt; + ip6_addr_t tmp; + + /* Check that Redir header fits in packet. */ + if (p->len < sizeof(struct redirect_header)) { + /* @todo debug message */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + + redir_hdr = (struct redirect_header *)p->payload; + + if (p->len >= (sizeof(struct redirect_header) + 2)) { + lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct redirect_header)); + if (p->len < (sizeof(struct redirect_header) + (lladdr_opt->length << 3))) { + lladdr_opt = NULL; + } + } else { + lladdr_opt = NULL; + } + + /* Copy original destination address to current source address, to have an aligned copy. */ + ip6_addr_set(&tmp, &(redir_hdr->destination_address)); + + /* Find dest address in cache */ + i = nd6_find_destination_cache_entry(&tmp); + if (i < 0) { + /* Destination not in cache, drop packet. */ + pbuf_free(p); + return; + } + + /* Set the new target address. */ + ip6_addr_set(&(destination_cache[i].next_hop_addr), &(redir_hdr->target_address)); + + /* If Link-layer address of other router is given, try to add to neighbor cache. */ + if (lladdr_opt != NULL) { + if (lladdr_opt->type == ND6_OPTION_TYPE_TARGET_LLADDR) { + /* Copy target address to current source address, to have an aligned copy. */ + ip6_addr_set(&tmp, &(redir_hdr->target_address)); + + i = nd6_find_neighbor_cache_entry(&tmp); + if (i < 0) { + i = nd6_new_neighbor_cache_entry(); + if (i >= 0) { + neighbor_cache[i].netif = inp; + MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len); + ip6_addr_set(&(neighbor_cache[i].next_hop_address), &tmp); + + /* Receiving a message does not prove reachability: only in one direction. + * Delay probe in case we get confirmation of reachability from upper layer (TCP). */ + neighbor_cache[i].state = ND6_DELAY; + neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL; + } + } + if (i >= 0) { + if (neighbor_cache[i].state == ND6_INCOMPLETE) { + MEMCPY(neighbor_cache[i].lladdr, lladdr_opt->addr, inp->hwaddr_len); + /* Receiving a message does not prove reachability: only in one direction. + * Delay probe in case we get confirmation of reachability from upper layer (TCP). */ + neighbor_cache[i].state = ND6_DELAY; + neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL; + } + } + } + } + break; /* ICMP6_TYPE_RD */ + } + case ICMP6_TYPE_PTB: /* Packet too big */ + { + struct icmp6_hdr *icmp6hdr; /* Packet too big message */ + struct ip6_hdr *ip6hdr; /* IPv6 header of the packet which caused the error */ + u32_t pmtu; + ip6_addr_t tmp; + + /* Check that ICMPv6 header + IPv6 header fit in payload */ + if (p->len < (sizeof(struct icmp6_hdr) + IP6_HLEN)) { + /* drop short packets */ + pbuf_free(p); + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + return; + } + + icmp6hdr = (struct icmp6_hdr *)p->payload; + ip6hdr = (struct ip6_hdr *)((u8_t*)p->payload + sizeof(struct icmp6_hdr)); + + /* Copy original destination address to current source address, to have an aligned copy. */ + ip6_addr_set(&tmp, &(ip6hdr->dest)); + + /* Look for entry in destination cache. */ + i = nd6_find_destination_cache_entry(&tmp); + if (i < 0) { + /* Destination not in cache, drop packet. */ + pbuf_free(p); + return; + } + + /* Change the Path MTU. */ + pmtu = lwip_htonl(icmp6hdr->data); + destination_cache[i].pmtu = (u16_t)LWIP_MIN(pmtu, 0xFFFF); + + break; /* ICMP6_TYPE_PTB */ + } + + default: + ND6_STATS_INC(nd6.proterr); + ND6_STATS_INC(nd6.drop); + break; /* default */ + } + + pbuf_free(p); +} + + +/** + * Periodic timer for Neighbor discovery functions: + * + * - Update neighbor reachability states + * - Update destination cache entries age + * - Update invalidation timers of default routers and on-link prefixes + * - Perform duplicate address detection (DAD) for our addresses + * - Send router solicitations + */ +void +nd6_tmr(void) +{ + s8_t i; + struct netif *netif; + + /* Process neighbor entries. */ + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + switch (neighbor_cache[i].state) { + case ND6_INCOMPLETE: + if ((neighbor_cache[i].counter.probes_sent >= LWIP_ND6_MAX_MULTICAST_SOLICIT) && + (!neighbor_cache[i].isrouter)) { + /* Retries exceeded. */ + nd6_free_neighbor_cache_entry(i); + } else { + /* Send a NS for this entry. */ + neighbor_cache[i].counter.probes_sent++; + nd6_send_neighbor_cache_probe(&neighbor_cache[i], ND6_SEND_FLAG_MULTICAST_DEST); + } + break; + case ND6_REACHABLE: + /* Send queued packets, if any are left. Should have been sent already. */ + if (neighbor_cache[i].q != NULL) { + nd6_send_q(i); + } + if (neighbor_cache[i].counter.reachable_time <= ND6_TMR_INTERVAL) { + /* Change to stale state. */ + neighbor_cache[i].state = ND6_STALE; + neighbor_cache[i].counter.stale_time = 0; + } else { + neighbor_cache[i].counter.reachable_time -= ND6_TMR_INTERVAL; + } + break; + case ND6_STALE: + neighbor_cache[i].counter.stale_time++; + break; + case ND6_DELAY: + if (neighbor_cache[i].counter.delay_time <= 1) { + /* Change to PROBE state. */ + neighbor_cache[i].state = ND6_PROBE; + neighbor_cache[i].counter.probes_sent = 0; + } else { + neighbor_cache[i].counter.delay_time--; + } + break; + case ND6_PROBE: + if ((neighbor_cache[i].counter.probes_sent >= LWIP_ND6_MAX_MULTICAST_SOLICIT) && + (!neighbor_cache[i].isrouter)) { + /* Retries exceeded. */ + nd6_free_neighbor_cache_entry(i); + } else { + /* Send a NS for this entry. */ + neighbor_cache[i].counter.probes_sent++; + nd6_send_neighbor_cache_probe(&neighbor_cache[i], 0); + } + break; + case ND6_NO_ENTRY: + default: + /* Do nothing. */ + break; + } + } + + /* Process destination entries. */ + for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) { + destination_cache[i].age++; + } + + /* Process router entries. */ + for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) { + if (default_router_list[i].neighbor_entry != NULL) { + /* Active entry. */ + if (default_router_list[i].invalidation_timer > 0) { + default_router_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000; + } + if (default_router_list[i].invalidation_timer < ND6_TMR_INTERVAL / 1000) { + /* Less than 1 second remaining. Clear this entry. */ + default_router_list[i].neighbor_entry->isrouter = 0; + default_router_list[i].neighbor_entry = NULL; + default_router_list[i].invalidation_timer = 0; + default_router_list[i].flags = 0; + } + } + } + + /* Process prefix entries. */ + for (i = 0; i < LWIP_ND6_NUM_PREFIXES; i++) { + if (prefix_list[i].netif != NULL) { + if (prefix_list[i].invalidation_timer < ND6_TMR_INTERVAL / 1000) { + /* Entry timed out, remove it */ + prefix_list[i].invalidation_timer = 0; + +#if LWIP_IPV6_AUTOCONFIG + /* If any addresses were configured with this prefix, remove them */ + if (prefix_list[i].flags & ND6_PREFIX_AUTOCONFIG_ADDRESS_GENERATED) { + s8_t j; + + for (j = 1; j < LWIP_IPV6_NUM_ADDRESSES; j++) { + if ((netif_ip6_addr_state(prefix_list[i].netif, j) != IP6_ADDR_INVALID) && + ip6_addr_netcmp(&prefix_list[i].prefix, netif_ip6_addr(prefix_list[i].netif, j))) { + netif_ip6_addr_set_state(prefix_list[i].netif, j, IP6_ADDR_INVALID); + prefix_list[i].flags = 0; + + /* Exit loop. */ + break; + } + } + } +#endif /* LWIP_IPV6_AUTOCONFIG */ + + prefix_list[i].netif = NULL; + prefix_list[i].flags = 0; + } else { + prefix_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000; + +#if LWIP_IPV6_AUTOCONFIG + /* Initiate address autoconfiguration for this prefix, if conditions are met. */ + if (prefix_list[i].netif->ip6_autoconfig_enabled && + (prefix_list[i].flags & ND6_PREFIX_AUTOCONFIG_AUTONOMOUS) && + !(prefix_list[i].flags & ND6_PREFIX_AUTOCONFIG_ADDRESS_GENERATED)) { + s8_t j; + /* Try to get an address on this netif that is invalid. + * Skip 0 index (link-local address) */ + for (j = 1; j < LWIP_IPV6_NUM_ADDRESSES; j++) { + if (netif_ip6_addr_state(prefix_list[i].netif, j) == IP6_ADDR_INVALID) { + /* Generate an address using this prefix and interface ID from link-local address. */ + netif_ip6_addr_set_parts(prefix_list[i].netif, j, + prefix_list[i].prefix.addr[0], prefix_list[i].prefix.addr[1], + netif_ip6_addr(prefix_list[i].netif, 0)->addr[2], netif_ip6_addr(prefix_list[i].netif, 0)->addr[3]); + + /* Mark it as tentative (DAD will be performed if configured). */ + netif_ip6_addr_set_state(prefix_list[i].netif, j, IP6_ADDR_TENTATIVE); + + /* Mark this prefix with ADDRESS_GENERATED, so that we don't try again. */ + prefix_list[i].flags |= ND6_PREFIX_AUTOCONFIG_ADDRESS_GENERATED; + + /* Exit loop. */ + break; + } + } + } +#endif /* LWIP_IPV6_AUTOCONFIG */ + } + } + } + + + /* Process our own addresses, if DAD configured. */ + for (netif = netif_list; netif != NULL; netif = netif->next) { + for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) { + u8_t addr_state = netif_ip6_addr_state(netif, i); + if (ip6_addr_istentative(addr_state)) { + if ((addr_state & IP6_ADDR_TENTATIVE_COUNT_MASK) >= LWIP_IPV6_DUP_DETECT_ATTEMPTS) { + /* No NA received in response. Mark address as valid. */ + netif_ip6_addr_set_state(netif, i, IP6_ADDR_PREFERRED); + /* @todo implement preferred and valid lifetimes. */ + } else if (netif->flags & NETIF_FLAG_UP) { + /* Send a NS for this address. */ + nd6_send_ns(netif, netif_ip6_addr(netif, i), ND6_SEND_FLAG_MULTICAST_DEST); + /* tentative: set next state by increasing by one */ + netif_ip6_addr_set_state(netif, i, addr_state + 1); + /* @todo send max 1 NS per tmr call? enable return*/ + /*return;*/ + } + } + } + } + +#if LWIP_IPV6_SEND_ROUTER_SOLICIT + /* Send router solicitation messages, if necessary. */ + for (netif = netif_list; netif != NULL; netif = netif->next) { + if ((netif->rs_count > 0) && (netif->flags & NETIF_FLAG_UP) && + (!ip6_addr_isinvalid(netif_ip6_addr_state(netif, 0)))) { + if (nd6_send_rs(netif) == ERR_OK) { + netif->rs_count--; + } + } + } +#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */ + +} + +/** Send a neighbor solicitation message for a specific neighbor cache entry + * + * @param entry the neightbor cache entry for wich to send the message + * @param flags one of ND6_SEND_FLAG_* + */ +static void +nd6_send_neighbor_cache_probe(struct nd6_neighbor_cache_entry *entry, u8_t flags) +{ + nd6_send_ns(entry->netif, &entry->next_hop_address, flags); +} + +/** + * Send a neighbor solicitation message + * + * @param netif the netif on which to send the message + * @param target_addr the IPv6 target address for the ND message + * @param flags one of ND6_SEND_FLAG_* + */ +static void +nd6_send_ns(struct netif *netif, const ip6_addr_t *target_addr, u8_t flags) +{ + struct ns_header *ns_hdr; + struct pbuf *p; + const ip6_addr_t *src_addr; + u16_t lladdr_opt_len; + + if (ip6_addr_isvalid(netif_ip6_addr_state(netif,0))) { + /* Use link-local address as source address. */ + src_addr = netif_ip6_addr(netif, 0); + /* calculate option length (in 8-byte-blocks) */ + lladdr_opt_len = ((netif->hwaddr_len + 2) + 7) >> 3; + } else { + src_addr = IP6_ADDR_ANY6; + /* Option "MUST NOT be included when the source IP address is the unspecified address." */ + lladdr_opt_len = 0; + } + + /* Allocate a packet. */ + p = pbuf_alloc(PBUF_IP, sizeof(struct ns_header) + (lladdr_opt_len << 3), PBUF_RAM); + if (p == NULL) { + ND6_STATS_INC(nd6.memerr); + return; + } + + /* Set fields. */ + ns_hdr = (struct ns_header *)p->payload; + + ns_hdr->type = ICMP6_TYPE_NS; + ns_hdr->code = 0; + ns_hdr->chksum = 0; + ns_hdr->reserved = 0; + ip6_addr_set(&(ns_hdr->target_address), target_addr); + + if (lladdr_opt_len != 0) { + struct lladdr_option *lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct ns_header)); + lladdr_opt->type = ND6_OPTION_TYPE_SOURCE_LLADDR; + lladdr_opt->length = (u8_t)lladdr_opt_len; + SMEMCPY(lladdr_opt->addr, netif->hwaddr, netif->hwaddr_len); + } + + /* Generate the solicited node address for the target address. */ + if (flags & ND6_SEND_FLAG_MULTICAST_DEST) { + ip6_addr_set_solicitednode(&multicast_address, target_addr->addr[3]); + target_addr = &multicast_address; + } + +#if CHECKSUM_GEN_ICMP6 + IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) { + ns_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len, src_addr, + target_addr); + } +#endif /* CHECKSUM_GEN_ICMP6 */ + + /* Send the packet out. */ + ND6_STATS_INC(nd6.xmit); + ip6_output_if(p, (src_addr == IP6_ADDR_ANY6) ? NULL : src_addr, target_addr, + LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif); + pbuf_free(p); +} + +/** + * Send a neighbor advertisement message + * + * @param netif the netif on which to send the message + * @param target_addr the IPv6 target address for the ND message + * @param flags one of ND6_SEND_FLAG_* + */ +static void +nd6_send_na(struct netif *netif, const ip6_addr_t *target_addr, u8_t flags) +{ + struct na_header *na_hdr; + struct lladdr_option *lladdr_opt; + struct pbuf *p; + const ip6_addr_t *src_addr; + const ip6_addr_t *dest_addr; + u16_t lladdr_opt_len; + + /* Use link-local address as source address. */ + /* src_addr = netif_ip6_addr(netif, 0); */ + /* Use target address as source address. */ + src_addr = target_addr; + + /* Allocate a packet. */ + lladdr_opt_len = ((netif->hwaddr_len + 2) >> 3) + (((netif->hwaddr_len + 2) & 0x07) ? 1 : 0); + p = pbuf_alloc(PBUF_IP, sizeof(struct na_header) + (lladdr_opt_len << 3), PBUF_RAM); + if (p == NULL) { + ND6_STATS_INC(nd6.memerr); + return; + } + + /* Set fields. */ + na_hdr = (struct na_header *)p->payload; + lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct na_header)); + + na_hdr->type = ICMP6_TYPE_NA; + na_hdr->code = 0; + na_hdr->chksum = 0; + na_hdr->flags = flags & 0xf0; + na_hdr->reserved[0] = 0; + na_hdr->reserved[1] = 0; + na_hdr->reserved[2] = 0; + ip6_addr_set(&(na_hdr->target_address), target_addr); + + lladdr_opt->type = ND6_OPTION_TYPE_TARGET_LLADDR; + lladdr_opt->length = (u8_t)lladdr_opt_len; + SMEMCPY(lladdr_opt->addr, netif->hwaddr, netif->hwaddr_len); + + /* Generate the solicited node address for the target address. */ + if (flags & ND6_SEND_FLAG_MULTICAST_DEST) { + ip6_addr_set_solicitednode(&multicast_address, target_addr->addr[3]); + dest_addr = &multicast_address; + } else if (flags & ND6_SEND_FLAG_ALLNODES_DEST) { + ip6_addr_set_allnodes_linklocal(&multicast_address); + dest_addr = &multicast_address; + } else { + dest_addr = ip6_current_src_addr(); + } + +#if CHECKSUM_GEN_ICMP6 + IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) { + na_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len, src_addr, + dest_addr); + } +#endif /* CHECKSUM_GEN_ICMP6 */ + + /* Send the packet out. */ + ND6_STATS_INC(nd6.xmit); + ip6_output_if(p, src_addr, dest_addr, + LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif); + pbuf_free(p); +} + +#if LWIP_IPV6_SEND_ROUTER_SOLICIT +/** + * Send a router solicitation message + * + * @param netif the netif on which to send the message + */ +static err_t +nd6_send_rs(struct netif *netif) +{ + struct rs_header *rs_hdr; + struct lladdr_option *lladdr_opt; + struct pbuf *p; + const ip6_addr_t *src_addr; + err_t err; + u16_t lladdr_opt_len = 0; + + /* Link-local source address, or unspecified address? */ + if (ip6_addr_isvalid(netif_ip6_addr_state(netif, 0))) { + src_addr = netif_ip6_addr(netif, 0); + } else { + src_addr = IP6_ADDR_ANY6; + } + + /* Generate the all routers target address. */ + ip6_addr_set_allrouters_linklocal(&multicast_address); + + /* Allocate a packet. */ + if (src_addr != IP6_ADDR_ANY6) { + lladdr_opt_len = ((netif->hwaddr_len + 2) >> 3) + (((netif->hwaddr_len + 2) & 0x07) ? 1 : 0); + } + p = pbuf_alloc(PBUF_IP, sizeof(struct rs_header) + (lladdr_opt_len << 3), PBUF_RAM); + if (p == NULL) { + ND6_STATS_INC(nd6.memerr); + return ERR_BUF; + } + + /* Set fields. */ + rs_hdr = (struct rs_header *)p->payload; + + rs_hdr->type = ICMP6_TYPE_RS; + rs_hdr->code = 0; + rs_hdr->chksum = 0; + rs_hdr->reserved = 0; + + if (src_addr != IP6_ADDR_ANY6) { + /* Include our hw address. */ + lladdr_opt = (struct lladdr_option *)((u8_t*)p->payload + sizeof(struct rs_header)); + lladdr_opt->type = ND6_OPTION_TYPE_SOURCE_LLADDR; + lladdr_opt->length = (u8_t)lladdr_opt_len; + SMEMCPY(lladdr_opt->addr, netif->hwaddr, netif->hwaddr_len); + } + +#if CHECKSUM_GEN_ICMP6 + IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) { + rs_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len, src_addr, + &multicast_address); + } +#endif /* CHECKSUM_GEN_ICMP6 */ + + /* Send the packet out. */ + ND6_STATS_INC(nd6.xmit); + + err = ip6_output_if(p, (src_addr == IP6_ADDR_ANY6) ? NULL : src_addr, &multicast_address, + LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif); + pbuf_free(p); + + return err; +} +#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */ + +/** + * Search for a neighbor cache entry + * + * @param ip6addr the IPv6 address of the neighbor + * @return The neighbor cache entry index that matched, -1 if no + * entry is found + */ +static s8_t +nd6_find_neighbor_cache_entry(const ip6_addr_t *ip6addr) +{ + s8_t i; + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + if (ip6_addr_cmp(ip6addr, &(neighbor_cache[i].next_hop_address))) { + return i; + } + } + return -1; +} + +/** + * Create a new neighbor cache entry. + * + * If no unused entry is found, will try to recycle an old entry + * according to ad-hoc "age" heuristic. + * + * @return The neighbor cache entry index that was created, -1 if no + * entry could be created + */ +static s8_t +nd6_new_neighbor_cache_entry(void) +{ + s8_t i; + s8_t j; + u32_t time; + + + /* First, try to find an empty entry. */ + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + if (neighbor_cache[i].state == ND6_NO_ENTRY) { + return i; + } + } + + /* We need to recycle an entry. in general, do not recycle if it is a router. */ + + /* Next, try to find a Stale entry. */ + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + if ((neighbor_cache[i].state == ND6_STALE) && + (!neighbor_cache[i].isrouter)) { + nd6_free_neighbor_cache_entry(i); + return i; + } + } + + /* Next, try to find a Probe entry. */ + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + if ((neighbor_cache[i].state == ND6_PROBE) && + (!neighbor_cache[i].isrouter)) { + nd6_free_neighbor_cache_entry(i); + return i; + } + } + + /* Next, try to find a Delayed entry. */ + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + if ((neighbor_cache[i].state == ND6_DELAY) && + (!neighbor_cache[i].isrouter)) { + nd6_free_neighbor_cache_entry(i); + return i; + } + } + + /* Next, try to find the oldest reachable entry. */ + time = 0xfffffffful; + j = -1; + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + if ((neighbor_cache[i].state == ND6_REACHABLE) && + (!neighbor_cache[i].isrouter)) { + if (neighbor_cache[i].counter.reachable_time < time) { + j = i; + time = neighbor_cache[i].counter.reachable_time; + } + } + } + if (j >= 0) { + nd6_free_neighbor_cache_entry(j); + return j; + } + + /* Next, find oldest incomplete entry without queued packets. */ + time = 0; + j = -1; + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + if ( + (neighbor_cache[i].q == NULL) && + (neighbor_cache[i].state == ND6_INCOMPLETE) && + (!neighbor_cache[i].isrouter)) { + if (neighbor_cache[i].counter.probes_sent >= time) { + j = i; + time = neighbor_cache[i].counter.probes_sent; + } + } + } + if (j >= 0) { + nd6_free_neighbor_cache_entry(j); + return j; + } + + /* Next, find oldest incomplete entry with queued packets. */ + time = 0; + j = -1; + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + if ((neighbor_cache[i].state == ND6_INCOMPLETE) && + (!neighbor_cache[i].isrouter)) { + if (neighbor_cache[i].counter.probes_sent >= time) { + j = i; + time = neighbor_cache[i].counter.probes_sent; + } + } + } + if (j >= 0) { + nd6_free_neighbor_cache_entry(j); + return j; + } + + /* No more entries to try. */ + return -1; +} + +/** + * Will free any resources associated with a neighbor cache + * entry, and will mark it as unused. + * + * @param i the neighbor cache entry index to free + */ +static void +nd6_free_neighbor_cache_entry(s8_t i) +{ + if ((i < 0) || (i >= LWIP_ND6_NUM_NEIGHBORS)) { + return; + } + if (neighbor_cache[i].isrouter) { + /* isrouter needs to be cleared before deleting a neighbor cache entry */ + return; + } + + /* Free any queued packets. */ + if (neighbor_cache[i].q != NULL) { + nd6_free_q(neighbor_cache[i].q); + neighbor_cache[i].q = NULL; + } + + neighbor_cache[i].state = ND6_NO_ENTRY; + neighbor_cache[i].isrouter = 0; + neighbor_cache[i].netif = NULL; + neighbor_cache[i].counter.reachable_time = 0; + ip6_addr_set_zero(&(neighbor_cache[i].next_hop_address)); +} + +/** + * Search for a destination cache entry + * + * @param ip6addr the IPv6 address of the destination + * @return The destination cache entry index that matched, -1 if no + * entry is found + */ +static s8_t +nd6_find_destination_cache_entry(const ip6_addr_t *ip6addr) +{ + s8_t i; + for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) { + if (ip6_addr_cmp(ip6addr, &(destination_cache[i].destination_addr))) { + return i; + } + } + return -1; +} + +/** + * Create a new destination cache entry. If no unused entry is found, + * will recycle oldest entry. + * + * @return The destination cache entry index that was created, -1 if no + * entry was created + */ +static s8_t +nd6_new_destination_cache_entry(void) +{ + s8_t i, j; + u32_t age; + + /* Find an empty entry. */ + for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) { + if (ip6_addr_isany(&(destination_cache[i].destination_addr))) { + return i; + } + } + + /* Find oldest entry. */ + age = 0; + j = LWIP_ND6_NUM_DESTINATIONS - 1; + for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) { + if (destination_cache[i].age > age) { + j = i; + } + } + + return j; +} + +/** + * Clear the destination cache. + * + * This operation may be necessary for consistency in the light of changing + * local addresses and/or use of the gateway hook. + */ +void +nd6_clear_destination_cache(void) +{ + int i; + + for (i = 0; i < LWIP_ND6_NUM_DESTINATIONS; i++) { + ip6_addr_set_any(&destination_cache[i].destination_addr); + } +} + +/** + * Determine whether an address matches an on-link prefix. + * + * @param ip6addr the IPv6 address to match + * @return 1 if the address is on-link, 0 otherwise + */ +static s8_t +nd6_is_prefix_in_netif(const ip6_addr_t *ip6addr, struct netif *netif) +{ + s8_t i; + for (i = 0; i < LWIP_ND6_NUM_PREFIXES; i++) { + if ((prefix_list[i].netif == netif) && + (prefix_list[i].invalidation_timer > 0) && + ip6_addr_netcmp(ip6addr, &(prefix_list[i].prefix))) { + return 1; + } + } + /* Check to see if address prefix matches a (manually?) configured address. */ + for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) { + if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) && + ip6_addr_netcmp(ip6addr, netif_ip6_addr(netif, i))) { + return 1; + } + } + return 0; +} + +/** + * Select a default router for a destination. + * + * @param ip6addr the destination address + * @param netif the netif for the outgoing packet, if known + * @return the default router entry index, or -1 if no suitable + * router is found + */ +static s8_t +nd6_select_router(const ip6_addr_t *ip6addr, struct netif *netif) +{ + s8_t i; + /* last_router is used for round-robin router selection (as recommended + * in RFC). This is more robust in case one router is not reachable, + * we are not stuck trying to resolve it. */ + static s8_t last_router; + (void)ip6addr; /* @todo match preferred routes!! (must implement ND6_OPTION_TYPE_ROUTE_INFO) */ + + /* @todo: implement default router preference */ + + /* Look for reachable routers. */ + for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) { + if (++last_router >= LWIP_ND6_NUM_ROUTERS) { + last_router = 0; + } + if ((default_router_list[i].neighbor_entry != NULL) && + (netif != NULL ? netif == default_router_list[i].neighbor_entry->netif : 1) && + (default_router_list[i].invalidation_timer > 0) && + (default_router_list[i].neighbor_entry->state == ND6_REACHABLE)) { + return i; + } + } + + /* Look for router in other reachability states, but still valid according to timer. */ + for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) { + if (++last_router >= LWIP_ND6_NUM_ROUTERS) { + last_router = 0; + } + if ((default_router_list[i].neighbor_entry != NULL) && + (netif != NULL ? netif == default_router_list[i].neighbor_entry->netif : 1) && + (default_router_list[i].invalidation_timer > 0)) { + return i; + } + } + + /* Look for any router for which we have any information at all. */ + for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) { + if (++last_router >= LWIP_ND6_NUM_ROUTERS) { + last_router = 0; + } + if (default_router_list[i].neighbor_entry != NULL && + (netif != NULL ? netif == default_router_list[i].neighbor_entry->netif : 1)) { + return i; + } + } + + /* no suitable router found. */ + return -1; +} + +/** + * Find a router-announced route to the given destination. + * + * The caller is responsible for checking whether the returned netif, if any, + * is in a suitable state (up, link up) to be used for packet transmission. + * + * @param ip6addr the destination IPv6 address + * @return the netif to use for the destination, or NULL if none found + */ +struct netif * +nd6_find_route(const ip6_addr_t *ip6addr) +{ + s8_t i; + + i = nd6_select_router(ip6addr, NULL); + if (i >= 0) { + if (default_router_list[i].neighbor_entry != NULL) { + return default_router_list[i].neighbor_entry->netif; /* may be NULL */ + } + } + + return NULL; +} + +/** + * Find an entry for a default router. + * + * @param router_addr the IPv6 address of the router + * @param netif the netif on which the router is found, if known + * @return the index of the router entry, or -1 if not found + */ +static s8_t +nd6_get_router(const ip6_addr_t *router_addr, struct netif *netif) +{ + s8_t i; + + /* Look for router. */ + for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) { + if ((default_router_list[i].neighbor_entry != NULL) && + ((netif != NULL) ? netif == default_router_list[i].neighbor_entry->netif : 1) && + ip6_addr_cmp(router_addr, &(default_router_list[i].neighbor_entry->next_hop_address))) { + return i; + } + } + + /* router not found. */ + return -1; +} + +/** + * Create a new entry for a default router. + * + * @param router_addr the IPv6 address of the router + * @param netif the netif on which the router is connected, if known + * @return the index on the router table, or -1 if could not be created + */ +static s8_t +nd6_new_router(const ip6_addr_t *router_addr, struct netif *netif) +{ + s8_t router_index; + s8_t free_router_index; + s8_t neighbor_index; + + /* Do we have a neighbor entry for this router? */ + neighbor_index = nd6_find_neighbor_cache_entry(router_addr); + if (neighbor_index < 0) { + /* Create a neighbor entry for this router. */ + neighbor_index = nd6_new_neighbor_cache_entry(); + if (neighbor_index < 0) { + /* Could not create neighbor entry for this router. */ + return -1; + } + ip6_addr_set(&(neighbor_cache[neighbor_index].next_hop_address), router_addr); + neighbor_cache[neighbor_index].netif = netif; + neighbor_cache[neighbor_index].q = NULL; + neighbor_cache[neighbor_index].state = ND6_INCOMPLETE; + neighbor_cache[neighbor_index].counter.probes_sent = 1; + nd6_send_neighbor_cache_probe(&neighbor_cache[neighbor_index], ND6_SEND_FLAG_MULTICAST_DEST); + } + + /* Mark neighbor as router. */ + neighbor_cache[neighbor_index].isrouter = 1; + + /* Look for empty entry. */ + free_router_index = LWIP_ND6_NUM_ROUTERS; + for (router_index = LWIP_ND6_NUM_ROUTERS - 1; router_index >= 0; router_index--) { + /* check if router already exists (this is a special case for 2 netifs on the same subnet + - e.g. wifi and cable) */ + if(default_router_list[router_index].neighbor_entry == &(neighbor_cache[neighbor_index])){ + return router_index; + } + if (default_router_list[router_index].neighbor_entry == NULL) { + /* remember lowest free index to create a new entry */ + free_router_index = router_index; + } + } + if (free_router_index < LWIP_ND6_NUM_ROUTERS) { + default_router_list[free_router_index].neighbor_entry = &(neighbor_cache[neighbor_index]); + return free_router_index; + } + + /* Could not create a router entry. */ + + /* Mark neighbor entry as not-router. Entry might be useful as neighbor still. */ + neighbor_cache[neighbor_index].isrouter = 0; + + /* router not found. */ + return -1; +} + +/** + * Find the cached entry for an on-link prefix. + * + * @param prefix the IPv6 prefix that is on-link + * @param netif the netif on which the prefix is on-link + * @return the index on the prefix table, or -1 if not found + */ +static s8_t +nd6_get_onlink_prefix(ip6_addr_t *prefix, struct netif *netif) +{ + s8_t i; + + /* Look for prefix in list. */ + for (i = 0; i < LWIP_ND6_NUM_PREFIXES; ++i) { + if ((ip6_addr_netcmp(&(prefix_list[i].prefix), prefix)) && + (prefix_list[i].netif == netif)) { + return i; + } + } + + /* Entry not available. */ + return -1; +} + +/** + * Creates a new entry for an on-link prefix. + * + * @param prefix the IPv6 prefix that is on-link + * @param netif the netif on which the prefix is on-link + * @return the index on the prefix table, or -1 if not created + */ +static s8_t +nd6_new_onlink_prefix(ip6_addr_t *prefix, struct netif *netif) +{ + s8_t i; + + /* Create new entry. */ + for (i = 0; i < LWIP_ND6_NUM_PREFIXES; ++i) { + if ((prefix_list[i].netif == NULL) || + (prefix_list[i].invalidation_timer == 0)) { + /* Found empty prefix entry. */ + prefix_list[i].netif = netif; + ip6_addr_set(&(prefix_list[i].prefix), prefix); +#if LWIP_IPV6_AUTOCONFIG + prefix_list[i].flags = 0; +#endif /* LWIP_IPV6_AUTOCONFIG */ + return i; + } + } + + /* Entry not available. */ + return -1; +} + +/** + * Determine the next hop for a destination. Will determine if the + * destination is on-link, else a suitable on-link router is selected. + * + * The last entry index is cached for fast entry search. + * + * @param ip6addr the destination address + * @param netif the netif on which the packet will be sent + * @return the neighbor cache entry for the next hop, ERR_RTE if no + * suitable next hop was found, ERR_MEM if no cache entry + * could be created + */ +static s8_t +nd6_get_next_hop_entry(const ip6_addr_t *ip6addr, struct netif *netif) +{ +#ifdef LWIP_HOOK_ND6_GET_GW + const ip6_addr_t *next_hop_addr; +#endif /* LWIP_HOOK_ND6_GET_GW */ + s8_t i; + +#if LWIP_NETIF_HWADDRHINT + if (netif->addr_hint != NULL) { + /* per-pcb cached entry was given */ + u8_t addr_hint = *(netif->addr_hint); + if (addr_hint < LWIP_ND6_NUM_DESTINATIONS) { + nd6_cached_destination_index = addr_hint; + } + } +#endif /* LWIP_NETIF_HWADDRHINT */ + + /* Look for ip6addr in destination cache. */ + if (ip6_addr_cmp(ip6addr, &(destination_cache[nd6_cached_destination_index].destination_addr))) { + /* the cached entry index is the right one! */ + /* do nothing. */ + ND6_STATS_INC(nd6.cachehit); + } else { + /* Search destination cache. */ + i = nd6_find_destination_cache_entry(ip6addr); + if (i >= 0) { + /* found destination entry. make it our new cached index. */ + nd6_cached_destination_index = i; + } else { + /* Not found. Create a new destination entry. */ + i = nd6_new_destination_cache_entry(); + if (i >= 0) { + /* got new destination entry. make it our new cached index. */ + nd6_cached_destination_index = i; + } else { + /* Could not create a destination cache entry. */ + return ERR_MEM; + } + + /* Copy dest address to destination cache. */ + ip6_addr_set(&(destination_cache[nd6_cached_destination_index].destination_addr), ip6addr); + + /* Now find the next hop. is it a neighbor? */ + if (ip6_addr_islinklocal(ip6addr) || + nd6_is_prefix_in_netif(ip6addr, netif)) { + /* Destination in local link. */ + destination_cache[nd6_cached_destination_index].pmtu = netif->mtu; + ip6_addr_copy(destination_cache[nd6_cached_destination_index].next_hop_addr, destination_cache[nd6_cached_destination_index].destination_addr); +#ifdef LWIP_HOOK_ND6_GET_GW + } else if ((next_hop_addr = LWIP_HOOK_ND6_GET_GW(netif, ip6addr)) != NULL) { + /* Next hop for destination provided by hook function. */ + destination_cache[nd6_cached_destination_index].pmtu = netif->mtu; + ip6_addr_set(&destination_cache[nd6_cached_destination_index].next_hop_addr, next_hop_addr); +#endif /* LWIP_HOOK_ND6_GET_GW */ + } else { + /* We need to select a router. */ + i = nd6_select_router(ip6addr, netif); + if (i < 0) { + /* No router found. */ + ip6_addr_set_any(&(destination_cache[nd6_cached_destination_index].destination_addr)); + return ERR_RTE; + } + destination_cache[nd6_cached_destination_index].pmtu = netif->mtu; /* Start with netif mtu, correct through ICMPv6 if necessary */ + ip6_addr_copy(destination_cache[nd6_cached_destination_index].next_hop_addr, default_router_list[i].neighbor_entry->next_hop_address); + } + } + } + +#if LWIP_NETIF_HWADDRHINT + if (netif->addr_hint != NULL) { + /* per-pcb cached entry was given */ + *(netif->addr_hint) = nd6_cached_destination_index; + } +#endif /* LWIP_NETIF_HWADDRHINT */ + + /* Look in neighbor cache for the next-hop address. */ + if (ip6_addr_cmp(&(destination_cache[nd6_cached_destination_index].next_hop_addr), + &(neighbor_cache[nd6_cached_neighbor_index].next_hop_address))) { + /* Cache hit. */ + /* Do nothing. */ + ND6_STATS_INC(nd6.cachehit); + } else { + i = nd6_find_neighbor_cache_entry(&(destination_cache[nd6_cached_destination_index].next_hop_addr)); + if (i >= 0) { + /* Found a matching record, make it new cached entry. */ + nd6_cached_neighbor_index = i; + } else { + /* Neighbor not in cache. Make a new entry. */ + i = nd6_new_neighbor_cache_entry(); + if (i >= 0) { + /* got new neighbor entry. make it our new cached index. */ + nd6_cached_neighbor_index = i; + } else { + /* Could not create a neighbor cache entry. */ + return ERR_MEM; + } + + /* Initialize fields. */ + ip6_addr_copy(neighbor_cache[i].next_hop_address, + destination_cache[nd6_cached_destination_index].next_hop_addr); + neighbor_cache[i].isrouter = 0; + neighbor_cache[i].netif = netif; + neighbor_cache[i].state = ND6_INCOMPLETE; + neighbor_cache[i].counter.probes_sent = 1; + nd6_send_neighbor_cache_probe(&neighbor_cache[i], ND6_SEND_FLAG_MULTICAST_DEST); + } + } + + /* Reset this destination's age. */ + destination_cache[nd6_cached_destination_index].age = 0; + + return nd6_cached_neighbor_index; +} + +/** + * Queue a packet for a neighbor. + * + * @param neighbor_index the index in the neighbor cache table + * @param q packet to be queued + * @return ERR_OK if succeeded, ERR_MEM if out of memory + */ +static err_t +nd6_queue_packet(s8_t neighbor_index, struct pbuf *q) +{ + err_t result = ERR_MEM; + struct pbuf *p; + int copy_needed = 0; +#if LWIP_ND6_QUEUEING + struct nd6_q_entry *new_entry, *r; +#endif /* LWIP_ND6_QUEUEING */ + + if ((neighbor_index < 0) || (neighbor_index >= LWIP_ND6_NUM_NEIGHBORS)) { + return ERR_ARG; + } + + /* IF q includes a PBUF_REF, PBUF_POOL or PBUF_RAM, we have no choice but + * to copy the whole queue into a new PBUF_RAM (see bug #11400) + * PBUF_ROMs can be left as they are, since ROM must not get changed. */ + p = q; + while (p) { + if (p->type != PBUF_ROM) { + copy_needed = 1; + break; + } + p = p->next; + } + if (copy_needed) { + /* copy the whole packet into new pbufs */ + p = pbuf_alloc(PBUF_LINK, q->tot_len, PBUF_RAM); + while ((p == NULL) && (neighbor_cache[neighbor_index].q != NULL)) { + /* Free oldest packet (as per RFC recommendation) */ +#if LWIP_ND6_QUEUEING + r = neighbor_cache[neighbor_index].q; + neighbor_cache[neighbor_index].q = r->next; + r->next = NULL; + nd6_free_q(r); +#else /* LWIP_ND6_QUEUEING */ + pbuf_free(neighbor_cache[neighbor_index].q); + neighbor_cache[neighbor_index].q = NULL; +#endif /* LWIP_ND6_QUEUEING */ + p = pbuf_alloc(PBUF_LINK, q->tot_len, PBUF_RAM); + } + if (p != NULL) { + if (pbuf_copy(p, q) != ERR_OK) { + pbuf_free(p); + p = NULL; + } + } + } else { + /* referencing the old pbuf is enough */ + p = q; + pbuf_ref(p); + } + /* packet was copied/ref'd? */ + if (p != NULL) { + /* queue packet ... */ +#if LWIP_ND6_QUEUEING + /* allocate a new nd6 queue entry */ + new_entry = (struct nd6_q_entry *)memp_malloc(MEMP_ND6_QUEUE); + if ((new_entry == NULL) && (neighbor_cache[neighbor_index].q != NULL)) { + /* Free oldest packet (as per RFC recommendation) */ + r = neighbor_cache[neighbor_index].q; + neighbor_cache[neighbor_index].q = r->next; + r->next = NULL; + nd6_free_q(r); + new_entry = (struct nd6_q_entry *)memp_malloc(MEMP_ND6_QUEUE); + } + if (new_entry != NULL) { + new_entry->next = NULL; + new_entry->p = p; + if (neighbor_cache[neighbor_index].q != NULL) { + /* queue was already existent, append the new entry to the end */ + r = neighbor_cache[neighbor_index].q; + while (r->next != NULL) { + r = r->next; + } + r->next = new_entry; + } else { + /* queue did not exist, first item in queue */ + neighbor_cache[neighbor_index].q = new_entry; + } + LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: queued packet %p on neighbor entry %"S16_F"\n", (void *)p, (s16_t)neighbor_index)); + result = ERR_OK; + } else { + /* the pool MEMP_ND6_QUEUE is empty */ + pbuf_free(p); + LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: could not queue a copy of packet %p (out of memory)\n", (void *)p)); + /* { result == ERR_MEM } through initialization */ + } +#else /* LWIP_ND6_QUEUEING */ + /* Queue a single packet. If an older packet is already queued, free it as per RFC. */ + if (neighbor_cache[neighbor_index].q != NULL) { + pbuf_free(neighbor_cache[neighbor_index].q); + } + neighbor_cache[neighbor_index].q = p; + LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: queued packet %p on neighbor entry %"S16_F"\n", (void *)p, (s16_t)neighbor_index)); + result = ERR_OK; +#endif /* LWIP_ND6_QUEUEING */ + } else { + LWIP_DEBUGF(LWIP_DBG_TRACE, ("ipv6: could not queue a copy of packet %p (out of memory)\n", (void *)q)); + /* { result == ERR_MEM } through initialization */ + } + + return result; +} + +#if LWIP_ND6_QUEUEING +/** + * Free a complete queue of nd6 q entries + * + * @param q a queue of nd6_q_entry to free + */ +static void +nd6_free_q(struct nd6_q_entry *q) +{ + struct nd6_q_entry *r; + LWIP_ASSERT("q != NULL", q != NULL); + LWIP_ASSERT("q->p != NULL", q->p != NULL); + while (q) { + r = q; + q = q->next; + LWIP_ASSERT("r->p != NULL", (r->p != NULL)); + pbuf_free(r->p); + memp_free(MEMP_ND6_QUEUE, r); + } +} +#endif /* LWIP_ND6_QUEUEING */ + +/** + * Send queued packets for a neighbor + * + * @param i the neighbor to send packets to + */ +static void +nd6_send_q(s8_t i) +{ + struct ip6_hdr *ip6hdr; + ip6_addr_t dest; +#if LWIP_ND6_QUEUEING + struct nd6_q_entry *q; +#endif /* LWIP_ND6_QUEUEING */ + + if ((i < 0) || (i >= LWIP_ND6_NUM_NEIGHBORS)) { + return; + } + +#if LWIP_ND6_QUEUEING + while (neighbor_cache[i].q != NULL) { + /* remember first in queue */ + q = neighbor_cache[i].q; + /* pop first item off the queue */ + neighbor_cache[i].q = q->next; + /* Get ipv6 header. */ + ip6hdr = (struct ip6_hdr *)(q->p->payload); + /* Create an aligned copy. */ + ip6_addr_set(&dest, &(ip6hdr->dest)); + /* send the queued IPv6 packet */ + (neighbor_cache[i].netif)->output_ip6(neighbor_cache[i].netif, q->p, &dest); + /* free the queued IP packet */ + pbuf_free(q->p); + /* now queue entry can be freed */ + memp_free(MEMP_ND6_QUEUE, q); + } +#else /* LWIP_ND6_QUEUEING */ + if (neighbor_cache[i].q != NULL) { + /* Get ipv6 header. */ + ip6hdr = (struct ip6_hdr *)(neighbor_cache[i].q->payload); + /* Create an aligned copy. */ + ip6_addr_set(&dest, &(ip6hdr->dest)); + /* send the queued IPv6 packet */ + (neighbor_cache[i].netif)->output_ip6(neighbor_cache[i].netif, neighbor_cache[i].q, &dest); + /* free the queued IP packet */ + pbuf_free(neighbor_cache[i].q); + neighbor_cache[i].q = NULL; + } +#endif /* LWIP_ND6_QUEUEING */ +} + +/** + * A packet is to be transmitted to a specific IPv6 destination on a specific + * interface. Check if we can find the hardware address of the next hop to use + * for the packet. If so, give the hardware address to the caller, which should + * use it to send the packet right away. Otherwise, enqueue the packet for + * later transmission while looking up the hardware address, if possible. + * + * As such, this function returns one of three different possible results: + * + * - ERR_OK with a non-NULL 'hwaddrp': the caller should send the packet now. + * - ERR_OK with a NULL 'hwaddrp': the packet has been enqueued for later. + * - not ERR_OK: something went wrong; forward the error upward in the stack. + * + * @param netif The lwIP network interface on which the IP packet will be sent. + * @param q The pbuf(s) containing the IP packet to be sent. + * @param ip6addr The destination IPv6 address of the packet. + * @param hwaddrp On success, filled with a pointer to a HW address or NULL (meaning + * the packet has been queued). + * @return + * - ERR_OK on success, ERR_RTE if no route was found for the packet, + * or ERR_MEM if low memory conditions prohibit sending the packet at all. + */ +err_t +nd6_get_next_hop_addr_or_queue(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr, const u8_t **hwaddrp) +{ + s8_t i; + + /* Get next hop record. */ + i = nd6_get_next_hop_entry(ip6addr, netif); + if (i < 0) { + /* failed to get a next hop neighbor record. */ + return i; + } + + /* Now that we have a destination record, send or queue the packet. */ + if (neighbor_cache[i].state == ND6_STALE) { + /* Switch to delay state. */ + neighbor_cache[i].state = ND6_DELAY; + neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME / ND6_TMR_INTERVAL; + } + /* @todo should we send or queue if PROBE? send for now, to let unicast NS pass. */ + if ((neighbor_cache[i].state == ND6_REACHABLE) || + (neighbor_cache[i].state == ND6_DELAY) || + (neighbor_cache[i].state == ND6_PROBE)) { + + /* Tell the caller to send out the packet now. */ + *hwaddrp = neighbor_cache[i].lladdr; + return ERR_OK; + } + + /* We should queue packet on this interface. */ + *hwaddrp = NULL; + return nd6_queue_packet(i, q); +} + + +/** + * Get the Path MTU for a destination. + * + * @param ip6addr the destination address + * @param netif the netif on which the packet will be sent + * @return the Path MTU, if known, or the netif default MTU + */ +u16_t +nd6_get_destination_mtu(const ip6_addr_t *ip6addr, struct netif *netif) +{ + s8_t i; + + i = nd6_find_destination_cache_entry(ip6addr); + if (i >= 0) { + if (destination_cache[i].pmtu > 0) { + return destination_cache[i].pmtu; + } + } + + if (netif != NULL) { + return netif->mtu; + } + + return 1280; /* Minimum MTU */ +} + + +#if LWIP_ND6_TCP_REACHABILITY_HINTS +/** + * Provide the Neighbor discovery process with a hint that a + * destination is reachable. Called by tcp_receive when ACKs are + * received or sent (as per RFC). This is useful to avoid sending + * NS messages every 30 seconds. + * + * @param ip6addr the destination address which is know to be reachable + * by an upper layer protocol (TCP) + */ +void +nd6_reachability_hint(const ip6_addr_t *ip6addr) +{ + s8_t i; + + /* Find destination in cache. */ + if (ip6_addr_cmp(ip6addr, &(destination_cache[nd6_cached_destination_index].destination_addr))) { + i = nd6_cached_destination_index; + ND6_STATS_INC(nd6.cachehit); + } else { + i = nd6_find_destination_cache_entry(ip6addr); + } + if (i < 0) { + return; + } + + /* Find next hop neighbor in cache. */ + if (ip6_addr_cmp(&(destination_cache[i].next_hop_addr), &(neighbor_cache[nd6_cached_neighbor_index].next_hop_address))) { + i = nd6_cached_neighbor_index; + ND6_STATS_INC(nd6.cachehit); + } else { + i = nd6_find_neighbor_cache_entry(&(destination_cache[i].next_hop_addr)); + } + if (i < 0) { + return; + } + + /* For safety: don't set as reachable if we don't have a LL address yet. Misuse protection. */ + if (neighbor_cache[i].state == ND6_INCOMPLETE || neighbor_cache[i].state == ND6_NO_ENTRY) { + return; + } + + /* Set reachability state. */ + neighbor_cache[i].state = ND6_REACHABLE; + neighbor_cache[i].counter.reachable_time = reachable_time; +} +#endif /* LWIP_ND6_TCP_REACHABILITY_HINTS */ + +/** + * Remove all prefix, neighbor_cache and router entries of the specified netif. + * + * @param netif points to a network interface + */ +void +nd6_cleanup_netif(struct netif *netif) +{ + u8_t i; + s8_t router_index; + for (i = 0; i < LWIP_ND6_NUM_PREFIXES; i++) { + if (prefix_list[i].netif == netif) { + prefix_list[i].netif = NULL; + prefix_list[i].flags = 0; + } + } + for (i = 0; i < LWIP_ND6_NUM_NEIGHBORS; i++) { + if (neighbor_cache[i].netif == netif) { + for (router_index = 0; router_index < LWIP_ND6_NUM_ROUTERS; router_index++) { + if (default_router_list[router_index].neighbor_entry == &neighbor_cache[i]) { + default_router_list[router_index].neighbor_entry = NULL; + default_router_list[router_index].flags = 0; + } + } + neighbor_cache[i].isrouter = 0; + nd6_free_neighbor_cache_entry(i); + } + } +} + +#if LWIP_IPV6_MLD +/** + * The state of a local IPv6 address entry is about to change. If needed, join + * or leave the solicited-node multicast group for the address. + * + * @param netif The netif that owns the address. + * @param addr_idx The index of the address. + * @param new_state The new (IP6_ADDR_) state for the address. + */ +void +nd6_adjust_mld_membership(struct netif *netif, s8_t addr_idx, u8_t new_state) +{ + u8_t old_state, old_member, new_member; + + old_state = netif_ip6_addr_state(netif, addr_idx); + + /* Determine whether we were, and should be, a member of the solicited-node + * multicast group for this address. For tentative addresses, the group is + * not joined until the address enters the TENTATIVE_1 (or VALID) state. */ + old_member = (old_state != IP6_ADDR_INVALID && old_state != IP6_ADDR_TENTATIVE); + new_member = (new_state != IP6_ADDR_INVALID && new_state != IP6_ADDR_TENTATIVE); + + if (old_member != new_member) { + ip6_addr_set_solicitednode(&multicast_address, netif_ip6_addr(netif, addr_idx)->addr[3]); + + if (new_member) { + mld6_joingroup_netif(netif, &multicast_address); + } else { + mld6_leavegroup_netif(netif, &multicast_address); + } + } +} +#endif /* LWIP_IPV6_MLD */ + +#endif /* LWIP_IPV6 */ |