/** * @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 * * * Please coordinate changes and requests with Ivan Delamer * */ #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 #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 ((prefix_opt->flags & ND6_PREFIX_FLAG_ON_LINK) && (prefix_opt->prefix_length == 64) && !ip6_addr_islinklocal(&(prefix_opt->prefix))) { /* 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 */