diff options
Diffstat (limited to 'lwip/src/core/ipv6/nd6.c')
| -rw-r--r-- | lwip/src/core/ipv6/nd6.c | 2434 |
1 files changed, 2434 insertions, 0 deletions
diff --git a/lwip/src/core/ipv6/nd6.c b/lwip/src/core/ipv6/nd6.c new file mode 100644 index 0000000..db0c132 --- /dev/null +++ b/lwip/src/core/ipv6/nd6.c @@ -0,0 +1,2434 @@ +/** + * @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/dhcp6.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 netif_addr_idx_t nd6_cached_destination_index; + +/* Multicast address holder. */ +static ip6_addr_t multicast_address; + +static u8_t nd6_tmr_rs_reduction; + +/* Static buffer to parse RA packet options */ +union ra_options { + struct lladdr_option lladdr; + struct mtu_option mtu; + struct prefix_option prefix; +#if LWIP_ND6_RDNSS_MAX_DNS_SERVERS + struct rdnss_option rdnss; +#endif +}; +static union ra_options nd6_ra_buffer; + +/* 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 s16_t nd6_find_destination_cache_entry(const ip6_addr_t *ip6addr); +static s16_t nd6_new_destination_cache_entry(void); +static int 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(const ip6_addr_t *prefix, struct netif *netif); +static s8_t nd6_new_onlink_prefix(const 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 +#define ND6_SEND_FLAG_ANY_SRC 0x04 +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); + + +/** + * A local address has been determined to be a duplicate. Take the appropriate + * action(s) on the address and the interface as a whole. + * + * @param netif the netif that owns the address + * @param addr_idx the index of the address detected to be a duplicate + */ +static void +nd6_duplicate_addr_detected(struct netif *netif, s8_t addr_idx) +{ + + /* Mark the address as duplicate, but leave its lifetimes alone. If this was + * a manually assigned address, it will remain in existence as duplicate, and + * as such be unusable for any practical purposes until manual intervention. + * If this was an autogenerated address, the address will follow normal + * expiration rules, and thus disappear once its valid lifetime expires. */ + netif_ip6_addr_set_state(netif, addr_idx, IP6_ADDR_DUPLICATED); + +#if LWIP_IPV6_AUTOCONFIG + /* If the affected address was the link-local address that we use to generate + * all other addresses, then we should not continue to use those derived + * addresses either, so mark them as duplicate as well. For autoconfig-only + * setups, this will make the interface effectively unusable, approaching the + * intention of RFC 4862 Sec. 5.4.5. @todo implement the full requirements */ + if (addr_idx == 0) { + s8_t i; + for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; i++) { + if (!ip6_addr_isinvalid(netif_ip6_addr_state(netif, i)) && + !netif_ip6_addr_isstatic(netif, i)) { + netif_ip6_addr_set_state(netif, i, IP6_ADDR_DUPLICATED); + } + } + } +#endif /* LWIP_IPV6_AUTOCONFIG */ +} + +#if LWIP_IPV6_AUTOCONFIG +/** + * We received a router advertisement that contains a prefix with the + * autoconfiguration flag set. Add or update an associated autogenerated + * address. + * + * @param netif the netif on which the router advertisement arrived + * @param prefix_opt a pointer to the prefix option data + * @param prefix_addr an aligned copy of the prefix address + */ +static void +nd6_process_autoconfig_prefix(struct netif *netif, + struct prefix_option *prefix_opt, const ip6_addr_t *prefix_addr) +{ + ip6_addr_t ip6addr; + u32_t valid_life, pref_life; + u8_t addr_state; + s8_t i, free_idx; + + /* The caller already checks RFC 4862 Sec. 5.5.3 points (a) and (b). We do + * the rest, starting with checks for (c) and (d) here. */ + valid_life = lwip_htonl(prefix_opt->valid_lifetime); + pref_life = lwip_htonl(prefix_opt->preferred_lifetime); + if (pref_life > valid_life || prefix_opt->prefix_length != 64) { + return; /* silently ignore this prefix for autoconfiguration purposes */ + } + + /* If an autogenerated address already exists for this prefix, update its + * lifetimes. An address is considered autogenerated if 1) it is not static + * (i.e., manually assigned), and 2) there is an advertised autoconfiguration + * prefix for it (the one we are processing here). This does not necessarily + * exclude the possibility that the address was actually assigned by, say, + * DHCPv6. If that distinction becomes important in the future, more state + * must be kept. As explained elsewhere we also update lifetimes of tentative + * and duplicate addresses. Skip address slot 0 (the link-local address). */ + for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; i++) { + addr_state = netif_ip6_addr_state(netif, i); + if (!ip6_addr_isinvalid(addr_state) && !netif_ip6_addr_isstatic(netif, i) && + ip6_addr_netcmp(prefix_addr, netif_ip6_addr(netif, i))) { + /* Update the valid lifetime, as per RFC 4862 Sec. 5.5.3 point (e). + * The valid lifetime will never drop to zero as a result of this. */ + u32_t remaining_life = netif_ip6_addr_valid_life(netif, i); + if (valid_life > ND6_2HRS || valid_life > remaining_life) { + netif_ip6_addr_set_valid_life(netif, i, valid_life); + } else if (remaining_life > ND6_2HRS) { + netif_ip6_addr_set_valid_life(netif, i, ND6_2HRS); + } + LWIP_ASSERT("bad valid lifetime", !netif_ip6_addr_isstatic(netif, i)); + /* Update the preferred lifetime. No bounds checks are needed here. In + * rare cases the advertisement may un-deprecate the address, though. + * Deprecation is left to the timer code where it is handled anyway. */ + if (pref_life > 0 && addr_state == IP6_ADDR_DEPRECATED) { + netif_ip6_addr_set_state(netif, i, IP6_ADDR_PREFERRED); + } + netif_ip6_addr_set_pref_life(netif, i, pref_life); + return; /* there should be at most one matching address */ + } + } + + /* No autogenerated address exists for this prefix yet. See if we can add a + * new one. However, if IPv6 autoconfiguration is administratively disabled, + * do not generate new addresses, but do keep updating lifetimes for existing + * addresses. Also, when adding new addresses, we must protect explicitly + * against a valid lifetime of zero, because again, we use that as a special + * value. The generated address would otherwise expire immediately anyway. + * Finally, the original link-local address must be usable at all. We start + * creating addresses even if the link-local address is still in tentative + * state though, and deal with the fallout of that upon DAD collision. */ + addr_state = netif_ip6_addr_state(netif, 0); + if (!netif->ip6_autoconfig_enabled || valid_life == IP6_ADDR_LIFE_STATIC || + ip6_addr_isinvalid(addr_state) || ip6_addr_isduplicated(addr_state)) { + return; + } + + /* Construct the new address that we intend to use, and then see if that + * address really does not exist. It might have been added manually, after + * all. As a side effect, find a free slot. Note that we cannot use + * netif_add_ip6_address() here, as it would return ERR_OK if the address + * already did exist, resulting in that address being given lifetimes. */ + IP6_ADDR(&ip6addr, prefix_addr->addr[0], prefix_addr->addr[1], + netif_ip6_addr(netif, 0)->addr[2], netif_ip6_addr(netif, 0)->addr[3]); + ip6_addr_assign_zone(&ip6addr, IP6_UNICAST, netif); + + free_idx = 0; + for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; i++) { + if (!ip6_addr_isinvalid(netif_ip6_addr_state(netif, i))) { + if (ip6_addr_cmp(&ip6addr, netif_ip6_addr(netif, i))) { + return; /* formed address already exists */ + } + } else if (free_idx == 0) { + free_idx = i; + } + } + if (free_idx == 0) { + return; /* no address slots available, try again on next advertisement */ + } + + /* Assign the new address to the interface. */ + ip_addr_copy_from_ip6(netif->ip6_addr[free_idx], ip6addr); + netif_ip6_addr_set_valid_life(netif, free_idx, valid_life); + netif_ip6_addr_set_pref_life(netif, free_idx, pref_life); + netif_ip6_addr_set_state(netif, free_idx, IP6_ADDR_TENTATIVE); +} +#endif /* LWIP_IPV6_AUTOCONFIG */ + +/** + * 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; + s16_t dest_idx; + + 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; + ip6_addr_t target_address; + + /* 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; + + /* Create an aligned, zoned copy of the target address. */ + ip6_addr_copy_from_packed(target_address, na_hdr->target_address); + ip6_addr_assign_zone(&target_address, IP6_UNICAST, inp); + + /* Check a subset of the other RFC 4861 Sec. 7.1.2 requirements. */ + if (IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || na_hdr->code != 0 || + ip6_addr_ismulticast(&target_address)) { + pbuf_free(p); + ND6_STATS_INC(nd6.proterr); + ND6_STATS_INC(nd6.drop); + return; + } + + /* @todo RFC MUST: if IP destination is multicast, Solicited flag is zero */ + /* @todo RFC MUST: all included options have a length greater than zero */ + + /* Unsolicited NA?*/ + if (ip6_addr_ismulticast(ip6_current_dest_addr())) { + /* This is an unsolicited NA. + * link-layer changed? + * part of DAD mechanism? */ + +#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_isduplicated(netif_ip6_addr_state(inp, i)) && + ip6_addr_cmp(&target_address, netif_ip6_addr(inp, i))) { + /* We are using a duplicate address. */ + nd6_duplicate_addr_detected(inp, i); + + 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 { + /* This is a solicited NA. + * neighbor address resolution response? + * neighbor unreachability detection response? */ + + /* 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; + ip6_addr_t target_address; + 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; + + /* Create an aligned, zoned copy of the target address. */ + ip6_addr_copy_from_packed(target_address, ns_hdr->target_address); + ip6_addr_assign_zone(&target_address, IP6_UNICAST, inp); + + /* Check a subset of the other RFC 4861 Sec. 7.1.1 requirements. */ + if (IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || ns_hdr->code != 0 || + ip6_addr_ismulticast(&target_address)) { + pbuf_free(p); + ND6_STATS_INC(nd6.proterr); + ND6_STATS_INC(nd6.drop); + return; + } + + /* @todo RFC MUST: all included options have a length greater than zero */ + /* @todo RFC MUST: if IP source is 'any', destination is solicited-node multicast address */ + /* @todo RFC MUST: if IP source is 'any', there is no source LL address option */ + + /* 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(&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(&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. */ + nd6_duplicate_addr_detected(inp, i); + } + } + } + } else { + /* 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; + } + + /* 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 be 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; + + /* Check a subset of the other RFC 4861 Sec. 6.1.2 requirements. */ + if (!ip6_addr_islinklocal(ip6_current_src_addr()) || + IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || ra_hdr->code != 0) { + pbuf_free(p); + ND6_STATS_INC(nd6.proterr); + ND6_STATS_INC(nd6.drop); + return; + } + + /* @todo RFC MUST: all included options have a length greater than zero */ + + /* If we are sending RS messages, stop. */ +#if LWIP_IPV6_SEND_ROUTER_SOLICIT + /* ensure at least one solicitation is sent (see RFC 4861, ch. 6.3.7) */ + if ((inp->rs_count < LWIP_ND6_MAX_MULTICAST_SOLICIT) || + (nd6_send_rs(inp) == ERR_OK)) { + inp->rs_count = 0; + } else { + inp->rs_count = 1; + } +#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; + +#if LWIP_IPV6_DHCP6 + /* Trigger DHCPv6 if enabled */ + dhcp6_nd6_ra_trigger(inp, ra_hdr->flags & ND6_RA_FLAG_MANAGED_ADDR_CONFIG, + ra_hdr->flags & ND6_RA_FLAG_OTHER_CONFIG); +#endif + + /* Offset to options. */ + offset = sizeof(struct ra_header); + + /* Process each option. */ + while ((p->tot_len - offset) >= 2) { + u8_t option_type; + u16_t option_len; + int option_len8 = pbuf_try_get_at(p, offset + 1); + if (option_len8 <= 0) { + /* read beyond end or zero length */ + goto lenerr_drop_free_return; + } + option_len = ((u8_t)option_len8) << 3; + if (option_len > p->tot_len - offset) { + /* short packet (option does not fit in) */ + goto lenerr_drop_free_return; + } + if (p->len == p->tot_len) { + /* no need to copy from contiguous pbuf */ + buffer = &((u8_t*)p->payload)[offset]; + } else { + /* check if this option fits into our buffer */ + if (option_len > sizeof(nd6_ra_buffer)) { + option_type = pbuf_get_at(p, offset); + /* invalid option length */ + if (option_type != ND6_OPTION_TYPE_RDNSS) { + goto lenerr_drop_free_return; + } + /* we allow RDNSS option to be longer - we'll just drop some servers */ + option_len = sizeof(nd6_ra_buffer); + } + buffer = (u8_t*)&nd6_ra_buffer; + option_len = pbuf_copy_partial(p, &nd6_ra_buffer, option_len, offset); + } + option_type = buffer[0]; + switch (option_type) { + case ND6_OPTION_TYPE_SOURCE_LLADDR: + { + struct lladdr_option *lladdr_opt; + if (option_len < sizeof(struct lladdr_option)) { + goto lenerr_drop_free_return; + } + 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; + u32_t mtu32; + if (option_len < sizeof(struct mtu_option)) { + goto lenerr_drop_free_return; + } + mtu_opt = (struct mtu_option *)buffer; + mtu32 = lwip_htonl(mtu_opt->mtu); + if ((mtu32 >= 1280) && (mtu32 <= 0xffff)) { +#if LWIP_ND6_ALLOW_RA_UPDATES + if (inp->mtu) { + /* don't set the mtu for IPv6 higher than the netif driver supports */ + inp->mtu6 = LWIP_MIN(inp->mtu, (u16_t)mtu32); + } else { + inp->mtu6 = (u16_t)mtu32; + } +#endif /* LWIP_ND6_ALLOW_RA_UPDATES */ + } + break; + } + case ND6_OPTION_TYPE_PREFIX_INFO: + { + struct prefix_option *prefix_opt; + ip6_addr_t prefix_addr; + if (option_len < sizeof(struct prefix_option)) { + goto lenerr_drop_free_return; + } + + prefix_opt = (struct prefix_option *)buffer; + + /* Get a memory-aligned copy of the prefix. */ + ip6_addr_copy_from_packed(prefix_addr, prefix_opt->prefix); + ip6_addr_assign_zone(&prefix_addr, IP6_UNICAST, inp); + + if (!ip6_addr_islinklocal(&prefix_addr)) { + if ((prefix_opt->flags & ND6_PREFIX_FLAG_ON_LINK) && + (prefix_opt->prefix_length == 64)) { + /* Add to on-link prefix list. */ + u32_t valid_life; + s8_t prefix; + + valid_life = lwip_htonl(prefix_opt->valid_lifetime); + + /* find cache entry for this prefix. */ + prefix = nd6_get_onlink_prefix(&prefix_addr, inp); + if (prefix < 0 && valid_life > 0) { + /* Create a new cache entry. */ + prefix = nd6_new_onlink_prefix(&prefix_addr, inp); + } + if (prefix >= 0) { + prefix_list[prefix].invalidation_timer = valid_life; + } + } +#if LWIP_IPV6_AUTOCONFIG + if (prefix_opt->flags & ND6_PREFIX_FLAG_AUTONOMOUS) { + /* Perform processing for autoconfiguration. */ + nd6_process_autoconfig_prefix(inp, prefix_opt, &prefix_addr); + } +#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; + u16_t copy_offset = offset + SIZEOF_RDNSS_OPTION_BASE; + struct rdnss_option * rdnss_opt; + if (option_len < SIZEOF_RDNSS_OPTION_BASE) { + goto lenerr_drop_free_return; + } + + 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; + + /* Copy directly from pbuf to get an aligned, zoned copy of the prefix. */ + if (pbuf_copy_partial(p, &rdnss_address, sizeof(ip6_addr_p_t), copy_offset) == sizeof(ip6_addr_p_t)) { + IP_SET_TYPE_VAL(rdnss_address, IPADDR_TYPE_V6); + ip6_addr_assign_zone(ip_2_ip6(&rdnss_address), IP6_UNKNOWN, inp); + + 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 * (u8_t)option_len8; + } + + break; /* ICMP6_TYPE_RA */ + } + case ICMP6_TYPE_RD: /* Redirect */ + { + struct redirect_header *redir_hdr; + struct lladdr_option *lladdr_opt; + ip6_addr_t destination_address, target_address; + + /* 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; + + /* Create an aligned, zoned copy of the destination address. */ + ip6_addr_copy_from_packed(destination_address, redir_hdr->destination_address); + ip6_addr_assign_zone(&destination_address, IP6_UNICAST, inp); + + /* Check a subset of the other RFC 4861 Sec. 8.1 requirements. */ + if (!ip6_addr_islinklocal(ip6_current_src_addr()) || + IP6H_HOPLIM(ip6_current_header()) != ND6_HOPLIM || + redir_hdr->code != 0 || ip6_addr_ismulticast(&destination_address)) { + pbuf_free(p); + ND6_STATS_INC(nd6.proterr); + ND6_STATS_INC(nd6.drop); + return; + } + + /* @todo RFC MUST: IP source address equals first-hop router for destination_address */ + /* @todo RFC MUST: ICMP target address is either link-local address or same as destination_address */ + /* @todo RFC MUST: all included options have a length greater than zero */ + + 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; + } + + /* Find dest address in cache */ + dest_idx = nd6_find_destination_cache_entry(&destination_address); + if (dest_idx < 0) { + /* Destination not in cache, drop packet. */ + pbuf_free(p); + return; + } + + /* Create an aligned, zoned copy of the target address. */ + ip6_addr_copy_from_packed(target_address, redir_hdr->target_address); + ip6_addr_assign_zone(&target_address, IP6_UNICAST, inp); + + /* Set the new target address. */ + ip6_addr_copy(destination_cache[dest_idx].next_hop_addr, 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) { + i = nd6_find_neighbor_cache_entry(&target_address); + 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_copy(neighbor_cache[i].next_hop_address, target_address); + + /* 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 destination_address; + + /* 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)); + + /* Create an aligned, zoned copy of the destination address. */ + ip6_addr_copy_from_packed(destination_address, ip6hdr->dest); + ip6_addr_assign_zone(&destination_address, IP6_UNKNOWN, inp); + + /* Look for entry in destination cache. */ + dest_idx = nd6_find_destination_cache_entry(&destination_address); + if (dest_idx < 0) { + /* Destination not in cache, drop packet. */ + pbuf_free(p); + return; + } + + /* Change the Path MTU. */ + pmtu = lwip_htonl(icmp6hdr->data); + destination_cache[dest_idx].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); + return; +lenerr_drop_free_return: + ND6_STATS_INC(nd6.lenerr); + ND6_STATS_INC(nd6.drop); + 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 + * - Update lifetimes of our addresses + * - 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 <= ND6_TMR_INTERVAL / 1000) { + /* No more than 1 second remaining. Clear this entry. Also clear any of + * its destination cache entries, as per RFC 4861 Sec. 5.3 and 6.3.5. */ + s8_t j; + for (j = 0; j < LWIP_ND6_NUM_DESTINATIONS; j++) { + if (ip6_addr_cmp(&destination_cache[j].next_hop_addr, + &default_router_list[i].neighbor_entry->next_hop_address)) { + ip6_addr_set_any(&destination_cache[j].destination_addr); + } + } + 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; + } else { + default_router_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000; + } + } + } + + /* 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; + prefix_list[i].netif = NULL; + } else { + prefix_list[i].invalidation_timer -= ND6_TMR_INTERVAL / 1000; + } + } + } + + /* Process our own addresses, updating address lifetimes and/or DAD state. */ + NETIF_FOREACH(netif) { + for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; ++i) { + u8_t addr_state; +#if LWIP_IPV6_ADDRESS_LIFETIMES + /* Step 1: update address lifetimes (valid and preferred). */ + addr_state = netif_ip6_addr_state(netif, i); + /* RFC 4862 is not entirely clear as to whether address lifetimes affect + * tentative addresses, and is even less clear as to what should happen + * with duplicate addresses. We choose to track and update lifetimes for + * both those types, although for different reasons: + * - for tentative addresses, the line of thought of Sec. 5.7 combined + * with the potentially long period that an address may be in tentative + * state (due to the interface being down) suggests that lifetimes + * should be independent of external factors which would include DAD; + * - for duplicate addresses, retiring them early could result in a new + * but unwanted attempt at marking them as valid, while retiring them + * late/never could clog up address slots on the netif. + * As a result, we may end up expiring addresses of either type here. + */ + if (!ip6_addr_isinvalid(addr_state) && + !netif_ip6_addr_isstatic(netif, i)) { + u32_t life = netif_ip6_addr_valid_life(netif, i); + if (life <= ND6_TMR_INTERVAL / 1000) { + /* The address has expired. */ + netif_ip6_addr_set_valid_life(netif, i, 0); + netif_ip6_addr_set_pref_life(netif, i, 0); + netif_ip6_addr_set_state(netif, i, IP6_ADDR_INVALID); + } else { + if (!ip6_addr_life_isinfinite(life)) { + life -= ND6_TMR_INTERVAL / 1000; + LWIP_ASSERT("bad valid lifetime", life != IP6_ADDR_LIFE_STATIC); + netif_ip6_addr_set_valid_life(netif, i, life); + } + /* The address is still here. Update the preferred lifetime too. */ + life = netif_ip6_addr_pref_life(netif, i); + if (life <= ND6_TMR_INTERVAL / 1000) { + /* This case must also trigger if 'life' was already zero, so as to + * deal correctly with advertised preferred-lifetime reductions. */ + netif_ip6_addr_set_pref_life(netif, i, 0); + if (addr_state == IP6_ADDR_PREFERRED) + netif_ip6_addr_set_state(netif, i, IP6_ADDR_DEPRECATED); + } else if (!ip6_addr_life_isinfinite(life)) { + life -= ND6_TMR_INTERVAL / 1000; + netif_ip6_addr_set_pref_life(netif, i, life); + } + } + } + /* The address state may now have changed, so reobtain it next. */ +#endif /* LWIP_IPV6_ADDRESS_LIFETIMES */ + /* Step 2: update DAD state. */ + 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. For dynamic + * addresses with an expired preferred lifetime, the state is set to + * deprecated right away. That should almost never happen, though. */ + addr_state = IP6_ADDR_PREFERRED; +#if LWIP_IPV6_ADDRESS_LIFETIMES + if (!netif_ip6_addr_isstatic(netif, i) && + netif_ip6_addr_pref_life(netif, i) == 0) { + addr_state = IP6_ADDR_DEPRECATED; + } +#endif /* LWIP_IPV6_ADDRESS_LIFETIMES */ + netif_ip6_addr_set_state(netif, i, addr_state); + } else if (netif_is_up(netif) && netif_is_link_up(netif)) { + /* tentative: set next state by increasing by one */ + netif_ip6_addr_set_state(netif, i, addr_state + 1); + /* Send a NS for this address. Use the unspecified address as source + * address in all cases (RFC 4862 Sec. 5.4.2), not in the least + * because as it is, we only consider multicast replies for DAD. */ + nd6_send_ns(netif, netif_ip6_addr(netif, i), + ND6_SEND_FLAG_MULTICAST_DEST | ND6_SEND_FLAG_ANY_SRC); + } + } + } + } + +#if LWIP_IPV6_SEND_ROUTER_SOLICIT + /* Send router solicitation messages, if necessary. */ + if (!nd6_tmr_rs_reduction) { + nd6_tmr_rs_reduction = (ND6_RTR_SOLICITATION_INTERVAL / ND6_TMR_INTERVAL) - 1; + NETIF_FOREACH(netif) { + if ((netif->rs_count > 0) && netif_is_up(netif) && + netif_is_link_up(netif) && + !ip6_addr_isinvalid(netif_ip6_addr_state(netif, 0)) && + !ip6_addr_isduplicated(netif_ip6_addr_state(netif, 0))) { + if (nd6_send_rs(netif) == ERR_OK) { + netif->rs_count--; + } + } + } + } else { + nd6_tmr_rs_reduction--; + } +#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; + + LWIP_ASSERT("target address is required", target_addr != NULL); + + if (!(flags & ND6_SEND_FLAG_ANY_SRC) && + 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_copy_to_packed(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]); + ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif); + 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, + ND6_HOPLIM, 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; + + LWIP_ASSERT("target address is required", target_addr != NULL); + + /* 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_copy_to_packed(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]); + ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif); + dest_addr = &multicast_address; + } else if (flags & ND6_SEND_FLAG_ALLNODES_DEST) { + ip6_addr_set_allnodes_linklocal(&multicast_address); + ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif); + 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, + ND6_HOPLIM, 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); + ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif); + + /* 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, + ND6_HOPLIM, 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 s16_t +nd6_find_destination_cache_entry(const ip6_addr_t *ip6addr) +{ + s16_t i; + + IP6_ADDR_ZONECHECK(ip6addr); + + 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 s16_t +nd6_new_destination_cache_entry(void) +{ + s16_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 or the subnet of a + * statically assigned address. + * + * @param ip6addr the IPv6 address to match + * @return 1 if the address is on-link, 0 otherwise + */ +static int +nd6_is_prefix_in_netif(const ip6_addr_t *ip6addr, struct netif *netif) +{ + s8_t i; + + /* Check to see if the address matches an on-link prefix. */ + 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 (= static) + * address. Static addresses have an implied /64 subnet assignment. Dynamic + * addresses (from autoconfiguration) have no implied subnet assignment, and + * are thus effectively /128 assignments. See RFC 5942 for more on this. */ + for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) { + if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) && + netif_ip6_addr_isstatic(netif, i) && + ip6_addr_netcmp(ip6addr, netif_ip6_addr(netif, i))) { + return 1; + } + } + return 0; +} + +/** + * Select a default router for a destination. + * + * This function is used both for routing and for finding a next-hop target for + * a packet. In the former case, the given netif is NULL, and the returned + * router entry must be for a netif suitable for sending packets (up, link up). + * In the latter case, the given netif is not NULL and restricts router choice. + * + * @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) +{ + struct netif *router_netif; + s8_t i, j, valid_router; + static s8_t last_router; + + LWIP_UNUSED_ARG(ip6addr); /* @todo match preferred routes!! (must implement ND6_OPTION_TYPE_ROUTE_INFO) */ + + /* @todo: implement default router preference */ + + /* Look for valid routers. A reachable router is preferred. */ + valid_router = -1; + for (i = 0; i < LWIP_ND6_NUM_ROUTERS; i++) { + /* Is the router netif both set and apppropriate? */ + if (default_router_list[i].neighbor_entry != NULL) { + router_netif = default_router_list[i].neighbor_entry->netif; + if ((router_netif != NULL) && (netif != NULL ? netif == router_netif : + (netif_is_up(router_netif) && netif_is_link_up(router_netif)))) { + /* Is the router valid, i.e., reachable or probably reachable as per + * RFC 4861 Sec. 6.3.6? Note that we will never return a router that + * has no neighbor cache entry, due to the netif association tests. */ + if (default_router_list[i].neighbor_entry->state != ND6_INCOMPLETE) { + /* Is the router known to be reachable? */ + if (default_router_list[i].neighbor_entry->state == ND6_REACHABLE) { + return i; /* valid and reachable - done! */ + } else if (valid_router < 0) { + valid_router = i; /* valid but not known to be reachable */ + } + } + } + } + } + if (valid_router >= 0) { + return valid_router; + } + + /* Look for any router for which we have any information at all. */ + /* last_router is used for round-robin selection of incomplete routers, as + * recommended in RFC 4861 Sec. 6.3.6 point (2). Advance only when picking a + * route, to select the same router as next-hop target in the common case. */ + if ((netif == NULL) && (++last_router >= LWIP_ND6_NUM_ROUTERS)) { + last_router = 0; + } + i = last_router; + for (j = 0; j < LWIP_ND6_NUM_ROUTERS; j++) { + if (default_router_list[i].neighbor_entry != NULL) { + router_netif = default_router_list[i].neighbor_entry->netif; + if ((router_netif != NULL) && (netif != NULL ? netif == router_netif : + (netif_is_up(router_netif) && netif_is_link_up(router_netif)))) { + return i; + } + } + if (++i >= LWIP_ND6_NUM_ROUTERS) { + i = 0; + } + } + + /* no suitable router found. */ + return -1; +} + +/** + * Find a router-announced route to the given destination. This route may be + * based on an on-link prefix or a default router. + * + * If a suitable route is found, the returned netif is guaranteed to be 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) +{ + struct netif *netif; + s8_t i; + + /* @todo decide if it makes sense to check the destination cache first */ + + /* Check if there is a matching on-link prefix. There may be multiple + * matches. Pick the first one that is associated with a suitable netif. */ + for (i = 0; i < LWIP_ND6_NUM_PREFIXES; ++i) { + netif = prefix_list[i].netif; + if ((netif != NULL) && ip6_addr_netcmp(&prefix_list[i].prefix, ip6addr) && + netif_is_up(netif) && netif_is_link_up(netif)) { + return netif; + } + } + + /* No on-link prefix match. Find a router that can forward the packet. */ + i = nd6_select_router(ip6addr, NULL); + if (i >= 0) { + LWIP_ASSERT("selected router must have a neighbor entry", + default_router_list[i].neighbor_entry != NULL); + return default_router_list[i].neighbor_entry->netif; + } + + 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; + + IP6_ADDR_ZONECHECK_NETIF(router_addr, netif); + + /* 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; + + IP6_ADDR_ZONECHECK_NETIF(router_addr, netif); + + /* 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(const 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(const 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); + 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; + s16_t dst_idx; + + IP6_ADDR_ZONECHECK_NETIF(ip6addr, netif); + +#if LWIP_NETIF_HWADDRHINT + if (netif->hints != NULL) { + /* per-pcb cached entry was given */ + netif_addr_idx_t addr_hint = netif->hints->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. */ + dst_idx = nd6_find_destination_cache_entry(ip6addr); + if (dst_idx >= 0) { + /* found destination entry. make it our new cached index. */ + LWIP_ASSERT("type overflow", (size_t)dst_idx < NETIF_ADDR_IDX_MAX); + nd6_cached_destination_index = (netif_addr_idx_t)dst_idx; + } else { + /* Not found. Create a new destination entry. */ + dst_idx = nd6_new_destination_cache_entry(); + if (dst_idx >= 0) { + /* got new destination entry. make it our new cached index. */ + LWIP_ASSERT("type overflow", (size_t)dst_idx < NETIF_ADDR_IDX_MAX); + nd6_cached_destination_index = (netif_addr_idx_t)dst_idx; + } 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_mtu6(netif); + 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_mtu6(netif); /* 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->hints != NULL) { + /* per-pcb cached entry was given */ + netif->hints->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 that must be copied, we have to copy the whole chain + * into a new PBUF_RAM. See the definition of PBUF_NEEDS_COPY for details. */ + p = q; + while (p) { + if (PBUF_NEEDS_COPY(p)) { + copy_needed = 1; + break; + } + p = p->next; + } + if (copy_needed) { + /* copy the whole packet into new pbufs */ + p = pbuf_clone(PBUF_LINK, PBUF_RAM, q); + 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_clone(PBUF_LINK, PBUF_RAM, q); + } + } 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_copy_from_packed(dest, ip6hdr->dest); + /* Restore the zone, if applicable. */ + ip6_addr_assign_zone(&dest, IP6_UNKNOWN, neighbor_cache[i].netif); + /* 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_copy_from_packed(dest, ip6hdr->dest); + /* Restore the zone, if applicable. */ + ip6_addr_assign_zone(&dest, IP6_UNKNOWN, neighbor_cache[i].netif); + /* 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) +{ + s16_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_mtu6(netif); + } + + 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; + s16_t dst_idx; + + /* Find destination in cache. */ + if (ip6_addr_cmp(ip6addr, &(destination_cache[nd6_cached_destination_index].destination_addr))) { + dst_idx = nd6_cached_destination_index; + ND6_STATS_INC(nd6.cachehit); + } else { + dst_idx = nd6_find_destination_cache_entry(ip6addr); + } + if (dst_idx < 0) { + return; + } + + /* Find next hop neighbor in cache. */ + if (ip6_addr_cmp(&(destination_cache[dst_idx].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[dst_idx].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; + } + } + 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); + } + } + /* Clear the destination cache, since many entries may now have become + * invalid for one of several reasons. As destination cache entries have no + * netif association, use a sledgehammer approach (this can be improved). */ + nd6_clear_destination_cache(); +} + +#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_DUPLICATED && old_state != IP6_ADDR_TENTATIVE); + new_member = (new_state != IP6_ADDR_INVALID && new_state != IP6_ADDR_DUPLICATED && new_state != IP6_ADDR_TENTATIVE); + + if (old_member != new_member) { + ip6_addr_set_solicitednode(&multicast_address, netif_ip6_addr(netif, addr_idx)->addr[3]); + ip6_addr_assign_zone(&multicast_address, IP6_MULTICAST, netif); + + if (new_member) { + mld6_joingroup_netif(netif, &multicast_address); + } else { + mld6_leavegroup_netif(netif, &multicast_address); + } + } +} +#endif /* LWIP_IPV6_MLD */ + +/** Netif was added, set up, or reconnected (link up) */ +void +nd6_restart_netif(struct netif *netif) +{ +#if LWIP_IPV6_SEND_ROUTER_SOLICIT + /* Send Router Solicitation messages (see RFC 4861, ch. 6.3.7). */ + netif->rs_count = LWIP_ND6_MAX_MULTICAST_SOLICIT; +#endif /* LWIP_IPV6_SEND_ROUTER_SOLICIT */ +} + +#endif /* LWIP_IPV6 */ |