/* * Copyright (C) 2015 Martine Lenders * * This file is subject to the terms and conditions of the GNU Lesser General * Public License v2.1. See the file LICENSE in the top level directory for * more details. */ /** * @defgroup net_gnrc_ndp IPv6 Neighbor discovery * @ingroup net_gnrc_icmpv6 * @brief GNRC's IPv6 Neighbor Discovery implementation * @{ * * @file * @brief Definitions for GNRC's IPv6 Neighbor Discovery * * @author Martine Lenders */ #ifndef GNRC_NDP_H_ #define GNRC_NDP_H_ #include #include #include "byteorder.h" #include "net/ndp.h" #include "net/gnrc/pkt.h" #include "net/gnrc/icmpv6.h" #include "net/ipv6/addr.h" #include "net/gnrc/ipv6/nc.h" #include "net/gnrc/ipv6/netif.h" #include "net/gnrc/ndp/host.h" #include "net/gnrc/ndp/internal.h" #include "net/gnrc/ndp/router.h" #include "net/gnrc/ndp/node.h" #ifdef __cplusplus extern "C" { #endif /** Message type for router timeouts */ #define GNRC_NDP_MSG_RTR_TIMEOUT (0x0210) /** Message type for address timeouts */ #define GNRC_NDP_MSG_ADDR_TIMEOUT (0x0211) /** Message type for multicast neighbor solicitation retransmissions */ #define GNRC_NDP_MSG_NBR_SOL_RETRANS (0x0212) /** Message type for periodic router advertisements */ #define GNRC_NDP_MSG_RTR_ADV_RETRANS (0x0213) /** Message type for delayed router advertisements */ #define GNRC_NDP_MSG_RTR_ADV_DELAY (0x0214) /** Message type for delayed router advertisements in a 6LoWPAN * 6LoWPAN needs a special handling, because router advertisements are only * sent after a short randomized delay, but not periodically. */ #define GNRC_NDP_MSG_RTR_ADV_SIXLOWPAN_DELAY (0x0215) /** Message type for periodic router solicitations */ #define GNRC_NDP_MSG_RTR_SOL_RETRANS (0x0216) /** Message type for neighbor cache state timeouts */ #define GNRC_NDP_MSG_NC_STATE_TIMEOUT (0x0217) /** * @name Host constants * @{ * @see * RFC 4861, section 10 * */ /** * @brief Upper bound for randomised delay in seconds for initial * router solicitation transmissions */ #define GNRC_NDP_MAX_RTR_SOL_DELAY (1U) /** * @brief Interval in seconds between initial router solicitation * transmissions */ #define GNRC_NDP_MAX_RTR_SOL_INT (4U) /** * @brief Maximum number of initial router solicitation transmissions */ #define GNRC_NDP_MAX_RTR_SOL_NUMOF (3U) /** @} */ /** * @name Node constants * @{ * @see * RFC 4861, section 10 * */ /** * @brief Maximum number of unanswered multicast neighbor solicitations * before address resolution is considered failed. */ #define GNRC_NDP_MAX_MC_NBR_SOL_NUMOF (3U) /** * @brief Maximum number of unanswered unicast neighbor solicitations before * an address is considered unreachable. */ #define GNRC_NDP_MAX_UC_NBR_SOL_NUMOF (3U) /** * @brief Upper bound of randomized delay in seconds for a solicited * neighbor advertisement transmission for an anycast target. */ #define GNRC_NDP_MAX_AC_TGT_DELAY (1U) /** * @brief Maximum number of unsolicited neighbor advertisements before on * link-layer address change. */ #define GNRC_NDP_MAX_NBR_ADV_NUMOF (3U) /** * @brief Base value in mircoseconds for computing randomised * reachable time. */ #define GNRC_NDP_REACH_TIME (30U * SEC_IN_USEC) /** * @brief Time in mircoseconds between retransmissions of neighbor * solicitations to a neighbor. */ #define GNRC_NDP_RETRANS_TIMER (1U * SEC_IN_USEC) /** * @brief Delay in seconds for neighbor cache entry between entering * DELAY state and entering PROBE state if no reachability * confirmation has been received. */ #define GNRC_NDP_FIRST_PROBE_DELAY (5U) /** * @brief Lower bound for randomised reachable time calculation. */ #define GNRC_NDP_MIN_RAND (5U) /** * @brief Upper bound for randomised reachable time calculation. */ #define GNRC_NDP_MAX_RAND (15U) /** @} */ /** * @name Router constants * @{ * @see * RFC 4861, section 10 * */ /** * @brief Initial router advertisement interval in seconds */ #define GNRC_NDP_MAX_INIT_RTR_ADV_INT (16U) /** * @brief Maximum number of initial router advertisement transmissions */ #define GNRC_NDP_MAX_INIT_RTR_ADV_NUMOF (3U) /** * @brief Maximum number of final router advertisement transmissions */ #define GNRC_NDP_MAX_FIN_RTR_ADV_NUMOF (3U) /** * @brief Minimum delay in seconds between router advertisement * transmissions */ #define GNRC_NDP_MIN_RTR_ADV_DELAY (3U) /** * @brief Upper bound for randomised delay in microseconds between router * solicitation reception and responding router advertisement * transmission. */ #define GNRC_NDP_MAX_RTR_ADV_DELAY (500U * MS_IN_USEC) /** @} */ /** * @brief Handles received neighbor solicitations. * * @param[in] iface The receiving interface. * @param[in] pkt The received packet. * @param[in] ipv6 The IPv6 header in @p pkt. * @param[in] nbr_sol The neighbor solicitation in @p pkt. * @param[in] icmpv6_size The overall size of the neighbor solicitation. */ void gnrc_ndp_nbr_sol_handle(kernel_pid_t iface, gnrc_pktsnip_t *pkt, ipv6_hdr_t *ipv6, ndp_nbr_sol_t *nbr_sol, size_t icmpv6_size); /** * @brief Handles received neighbor advertisements. * * @param[in] iface The receiving interface. * @param[in] pkt The received packet. * @param[in] ipv6 The IPv6 header in @p pkt. * @param[in] nbr_adv The neighbor advertisement in @p pkt. * @param[in] icmpv6_size The overall size of the neighbor advertisement. */ void gnrc_ndp_nbr_adv_handle(kernel_pid_t iface, gnrc_pktsnip_t *pkt, ipv6_hdr_t *ipv6, ndp_nbr_adv_t *nbr_adv, size_t icmpv6_size); #if (defined(MODULE_GNRC_NDP_ROUTER) || defined(MODULE_GNRC_SIXLOWPAN_ND_ROUTER)) /** * @brief Handles received router solicitations. * * @param[in] iface The receiving interface. * @param[in] pkt The received packet. * @param[in] ipv6 The IPv6 header in @p pkt. * @param[in] rtr_sol The router solicitation in @p pkt. * @param[in] icmpv6_size The overall size of the router solicitation. */ void gnrc_ndp_rtr_sol_handle(kernel_pid_t iface, gnrc_pktsnip_t *pkt, ipv6_hdr_t *ipv6, ndp_rtr_sol_t *rtr_sol, size_t icmpv6_size); #else /** * @brief A host *must* silently discard all received router solicitations. * @see * RFC 4861, section 6.2.6 * * * This macro is primarily an optimization to not go into the function defined * above. */ #define gnrc_ndp_rtr_sol_handle(iface, pkt, ipv6, rtr_sol, size) #endif /** * @brief Handles received router advertisements * * @todo As router check consistency as described in RFC 4861, section 6.2.3 * * @param[in] iface The receiving interface. * @param[in] pkt The received packet. * @param[in] ipv6 The IPv6 header in @p pkt. * @param[in] rtr_adv The router advertisement in @p pkt. * @param[in] icmpv6_size The overall size of the router advertisement. */ void gnrc_ndp_rtr_adv_handle(kernel_pid_t iface, gnrc_pktsnip_t *pkt, ipv6_hdr_t *ipv6, ndp_rtr_adv_t *rtr_adv, size_t icmpv6_size); /** * @brief Retransmits a multicast neighbor solicitation for an incomplete or * probing neighbor cache entry @p nc_entry, * if nc_entry::probes_remaining > 0. * * @details If nc_entry::probes_remaining > 0 it will be decremented. If it * reaches 0 it the entry @p nc_entry will be removed from the * neighbor cache. * * @param[in] nc_entry A neighbor cache entry. Will be ignored if its state * is not @ref GNRC_IPV6_NC_STATE_INCOMPLETE or * @ref GNRC_IPV6_NC_STATE_PROBE. */ void gnrc_ndp_retrans_nbr_sol(gnrc_ipv6_nc_t *nc_entry); /** * @brief Event handler for a neighbor cache state timeout. * * @param[in] nc_entry A neighbor cache entry. */ void gnrc_ndp_state_timeout(gnrc_ipv6_nc_t *nc_entry); /** * @brief NDP interface initialization. * * @param[in] iface An IPv6 interface descriptor. Must not be NULL. */ void gnrc_ndp_netif_add(gnrc_ipv6_netif_t *iface); /** * @brief NDP interface removal. * * @param[in] iface An IPv6 interface descriptor. Must not be NULL. */ void gnrc_ndp_netif_remove(gnrc_ipv6_netif_t *iface); /** * @brief Get link-layer address and interface for next hop to destination * IPv6 address. * * @param[out] l2addr The link-layer for the next hop to @p dst. * @param[out] l2addr_len Length of @p l2addr. * @param[in] iface The interface to search the next hop on. * May be @ref KERNEL_PID_UNDEF if not specified. * @param[in] dst An IPv6 address to search the next hop for. * @param[in] pkt Packet to send to @p dst. Leave NULL if you * just want to get the addresses. * * @return The PID of the interface, on success. * @return -EHOSTUNREACH, if @p dst is not reachable. * @return -ENOBUFS, if @p l2addr_len was smaller than the resulting @p l2addr * would be long. */ kernel_pid_t gnrc_ndp_next_hop_l2addr(uint8_t *l2addr, uint8_t *l2addr_len, kernel_pid_t iface, ipv6_addr_t *dst, gnrc_pktsnip_t *pkt); /** * @brief Builds a neighbor solicitation message for sending. * * @see * RFC 4861, section 4.3 * * * @param[in] tgt The target address. * @param[in] options Options to append to the router solicitation. * * @return The resulting ICMPv6 packet on success. * @return NULL, on failure. */ gnrc_pktsnip_t *gnrc_ndp_nbr_sol_build(ipv6_addr_t *tgt, gnrc_pktsnip_t *options); /** * @brief Builds a neighbor advertisement message for sending. * * @see * RFC 4861, section 4.4 * * * @param[in] flags Neighbor advertisement flags: * @ref NDP_NBR_ADV_FLAGS_R == 1 indicates, that the * sender is a router, * @ref NDP_NBR_ADV_FLAGS_S == 1 indicates that the * advertisement was sent in response to a neighbor * solicitation, * @ref NDP_NBR_ADV_FLAGS_O == 1 indicates that the * advertisement should override an existing cache entry * and update the cached link-layer address. * @param[in] tgt For solicited advertisements, the Target Address field * in the neighbor solicitaton. * For and unsolicited advertisement, the address whose * link-layer address has changed. * MUST NOT be multicast. * @param[in] options Options to append to the neighbor advertisement. * * @return The resulting ICMPv6 packet on success. * @return NULL, on failure. */ gnrc_pktsnip_t *gnrc_ndp_nbr_adv_build(uint8_t flags, ipv6_addr_t *tgt, gnrc_pktsnip_t *options); /** * @brief Builds a router solicitation message for sending. * * @see * RFC 4861, section 4.1 * * * @param[in] options Options to append to the router solicitation. * * @return The resulting ICMPv6 packet on success. * @return NULL, on failure. */ gnrc_pktsnip_t *gnrc_ndp_rtr_sol_build(gnrc_pktsnip_t *options); /** * @brief Builds a router solicitation message for sending. * * @see * RFC 4861, section 4.1 * * * @param[in] options Options to append to the router solicitation. * * @return The resulting ICMPv6 packet on success. * @return NULL, on failure. */ gnrc_pktsnip_t *gnrc_ndp_rtr_sol_build(gnrc_pktsnip_t *options); #if (defined(MODULE_GNRC_NDP_ROUTER) || defined(MODULE_GNRC_SIXLOWPAN_ND_ROUTER)) /** * @brief Builds a router advertisement message for sending. * * @see * RFC 4861, section 4.2 * * * @note The source address for the packet MUST be the link-local address * of the interface. * * @param[in] cur_hl Default hop limit for outgoing IP packets, 0 if * unspecified by this router. * @param[in] flags Flags as defined above. * @ref NDP_RTR_ADV_FLAGS_M == 1 indicates, that the * addresses are managed by DHCPv6, * @ref NDP_RTR_ADV_FLAGS_O == 1 indicates that other * configuration information is available via DHCPv6. * @param[in] ltime Lifetime of the default router in seconds. * @param[in] reach_time Time in milliseconds a node should assume a neighbor * reachable. 0 means unspecified by the router. * @param[in] retrans_timer Time in milliseconds between retransmitted * neighbor solicitations. 0 means unspecified by * the router. * @param[in] options Options to append to the router advertisement. * * @return The resulting ICMPv6 packet on success. * @return NULL, on failure. */ gnrc_pktsnip_t *gnrc_ndp_rtr_adv_build(uint8_t cur_hl, uint8_t flags, uint16_t ltime, uint32_t reach_time, uint32_t retrans_timer, gnrc_pktsnip_t *options); #else /** * @brief A host *must not* send router advertisements at any time (so why build them?) * @see * RFC 4861, section 6.3.4 * * * This macro is primarily an optimization to not go into the function defined * above. */ #define gnrc_ndp_rtr_adv_build(cur_hl, flags, ltime, reach_time, retrans_timer, options) (NULL) #endif /** * @brief Builds a generic NDP option. * * @param[in] type Type of the option. * @param[in] size Size in byte of the option (will be rounded up to the next * multiple of 8). * @param[in] next More options in the packet. NULL, if there are none. * * @return The packet snip list of options, on success * @return NULL, if packet buffer is full */ gnrc_pktsnip_t *gnrc_ndp_opt_build(uint8_t type, size_t size, gnrc_pktsnip_t *next); /** * @brief Builds the source link-layer address option. * * @see * RFC 4861, section 4.6.1 * * * @note Must only be used with neighbor solicitations, router solicitations, * and router advertisements. This is not checked however, since * hosts should silently ignore it in other NDP messages. * * @param[in] l2addr A link-layer address of variable length. * @param[in] l2addr_len Length of @p l2addr. * @param[in] next More options in the packet. NULL, if there are none. * * @return The packet snip list of options, on success * @return NULL, if packet buffer is full */ gnrc_pktsnip_t *gnrc_ndp_opt_sl2a_build(const uint8_t *l2addr, uint8_t l2addr_len, gnrc_pktsnip_t *next); /** * @brief Builds the target link-layer address option. * * @see * RFC 4861, section 4.6.1 * * * @note Must only be used with neighbor advertisemnents and redirect packets. * This is not checked however, since hosts should silently ignore it * in other NDP messages. * * @param[in] l2addr A link-layer address of variable length. * @param[in] l2addr_len Length of @p l2addr. * @param[in] next More options in the packet. NULL, if there are none. * * @return The pkt snip list of options, on success * @return NULL, if packet buffer is full */ gnrc_pktsnip_t *gnrc_ndp_opt_tl2a_build(const uint8_t *l2addr, uint8_t l2addr_len, gnrc_pktsnip_t *next); #if (defined(MODULE_GNRC_NDP_ROUTER) || defined(MODULE_GNRC_SIXLOWPAN_ND_ROUTER)) /** * @brief Builds the prefix information option. * * @see * RFC 4861, section 4.6.2 * * * @note Must only be used with router advertisemnents. This is not checked * however, since nodes should silently ignore it in other NDP messages. * * @param[in] prefix_len The length of @p prefix in bits. Must be between * 0 and 128. * @param[in] flags Flags as defined above. * @ref NDP_OPT_PI_FLAGS_L == 1 indicates, that * @p prefix can be used for on-link determination, * @ref NDP_OPT_PI_FLAGS_A == 1 indicates, that * @p prefix can be used for stateless address * configuration. * @param[in] valid_ltime Length of time in seconds that @p prefix is valid. * UINT32_MAX represents infinity. * @param[in] pref_ltime Length of time in seconds that addresses using * @p prefix remain prefered. UINT32_MAX represents * infinity. * @param[in] prefix An IPv6 address or a prefix of an IPv6 address. * @param[in] next More options in the packet. NULL, if there are none. * * @return The packet snip list of options, on success * @return NULL, if packet buffer is full */ gnrc_pktsnip_t *gnrc_ndp_opt_pi_build(uint8_t prefix_len, uint8_t flags, uint32_t valid_ltime, uint32_t pref_ltime, ipv6_addr_t *prefix, gnrc_pktsnip_t *next); /** * @brief Builds the MTU option. * * @see * RFC 4861, section 4.6.4 * * * @note Must only be used with router advertisemnents. This is not checked * however, since nodes should silently ignore it in other NDP messages. * * @param[in] mtu The recommended MTU for the link. * @param[in] next More options in the packet. NULL, if there are none. * * @return The packet snip list of options, on success * @return NULL, if packet buffer is full */ gnrc_pktsnip_t *gnrc_ndp_opt_mtu_build(uint32_t mtu, gnrc_pktsnip_t *next); #else /** * @brief A host *must not* send router advertisements at any time (so why build their options?) * @see * RFC 4861, section 6.3.4 * * * This macro is primarily an optimization to not go into the function defined * above. */ #define gnrc_ndp_opt_pi_build(prefix_len, flags, valid_ltime, pref_ltime, prefix, next) (NULL) /** * @brief A host *must not* send router advertisements at any time (so why build their options?) * @see * RFC 4861, section 6.3.4 * * * This macro is primarily an optimization to not go into the function defined * above. */ #define gnrc_ndp_opt_mtu_build(mtu, next) (NULL) #endif #ifdef __cplusplus } #endif #endif /* GNRC_NDP_H_ */ /** * @} */