ng_ndp: initial import of address resolution

Makefile.dep

@@ -72,6 +72,13 @@ ifneq (,$(filter ng_sixlowpan_ctx,$(USEMODULE)))
   USEMODULE += vtimer
 endif
 
+ifneq (,$(filter ng_ndp,$(USEMODULE)))
+  USEMODULE += ng_icmpv6
+  USEMODULE += random
+  USEMODULE += timex
+  USEMODULE += vtimer
+endif
+
 ifneq (,$(filter ng_icmpv6_echo,$(USEMODULE)))
   USEMODULE += ng_icmpv6
   USEMODULE += ng_netbase
@@ -97,7 +104,11 @@ ifneq (,$(filter ng_ipv6,$(USEMODULE)))
   USEMODULE += ng_ipv6_hdr
   USEMODULE += ng_ipv6_nc
   USEMODULE += ng_ipv6_netif
+  USEMODULE += ng_ndp
   USEMODULE += ng_netbase
+  USEMODULE += random
+  USEMODULE += timex
+  USEMODULE += vtimer
 endif
 
 ifneq (,$(filter ng_ipv6_nc,$(USEMODULE)))

sys/Makefile

@@ -86,6 +86,9 @@ endif
 ifneq (,$(filter ng_inet_csum,$(USEMODULE)))
     DIRS += net/crosslayer/ng_inet_csum
 endif
+ifneq (,$(filter ng_ndp,$(USEMODULE)))
+    DIRS += net/network_layer/ng_ndp
+endif
 ifneq (,$(filter ng_netapi,$(USEMODULE)))
     DIRS += net/crosslayer/ng_netapi
 endif

sys/include/net/ng_ipv6.h

@@ -62,6 +62,16 @@ extern "C" {
 #define NG_IPV6_MSG_QUEUE_SIZE  (8U)
 #endif
 
+/**
+ * @brief   The PID to the IPv6 thread.
+ *
+ * @note    Use @ref ng_ipv6_init() to initialize. **Do not set by hand**.
+ *
+ * @details This variable is preferred for IPv6 internal communication *only*.
+ *          Please use @ref net_ng_netreg for external communication.
+ */
+extern kernel_pid_t ng_ipv6_pid;
+
 /**
  * @brief   Initialization of the IPv6 thread.
  *

sys/include/net/ng_ipv6/nc.h

@@ -137,7 +137,7 @@ typedef struct {
      */
     vtimer_t nbr_adv_timer;
 
-    uint8_t unanswered_probes;              /**< number of unanswered probes */
+    uint8_t probes_remaining;               /**< remaining number of unanswered probes */
     /**
      * @}
      */

sys/include/net/ng_ipv6/netif.h

@@ -195,6 +195,29 @@ typedef struct {
     uint16_t mtu;           /**< Maximum Transmission Unit (MTU) of the interface */
     uint8_t cur_hl;         /**< current hop limit for the interface */
     uint16_t flags;         /**< flags for 6LoWPAN and Neighbor Discovery */
+    /**
+     * @brief   Base value in microseconds for computing random
+     *          ng_ipv6_netif_t::reach_time.
+     *          The default value is @ref NG_NDP_REACH_TIME.
+     */
+    uint32_t reach_time_base;
+
+    /**
+     * @brief   The time a neighbor is considered reachable after receiving
+     *          a reachability confirmation.
+     *          Should be uniformly distributed between @ref NG_NDP_MIN_RAND
+     *          and NG_NDP_MAX_RAND multiplied with
+     *          ng_ipv6_netif_t::reach_time_base microseconds devided by 10.
+     *          Can't be greater than 1 hour.
+     */
+    timex_t reach_time;
+
+    /**
+     * @brief   Time between retransmissions of neighbor solicitations to a
+     *          neighbor.
+     *          The default value is @ref NG_NDP_RETRANS_TIMER.
+     */
+    timex_t retrans_timer;
 } ng_ipv6_netif_t;
 
 /**

sys/include/net/ng_ndp.h

@@ -0,0 +1,297 @@
+/*
+ * Copyright (C) 2015 Martine Lenders <[email protected]>
+ *
+ * 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_ng_ndp  IPv6 Neighbor discovery
+ * @ingroup     net_ng_icmpv6
+ * @brief       IPv6 Neighbor Discovery Implementation
+ * @{
+ *
+ * @file
+ * @brief       Neighbor Discovery definitions
+ *
+ * @author      Martine Lenders <[email protected]>
+ */
+
+#include <inttypes.h>
+
+#include "byteorder.h"
+#include "net/ng_pkt.h"
+#include "net/ng_icmpv6.h"
+#include "net/ng_ipv6/addr.h"
+#include "net/ng_ipv6/nc.h"
+#include "net/ng_ipv6/netif.h"
+
+#include "net/ng_ndp/types.h"
+
+#ifndef NG_NDP_H_
+#define NG_NDP_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define NG_NDP_MSG_RTR_TIMEOUT      (0x0211)    /**< Message type for router timeouts */
+#define NG_NDP_MSG_ADDR_TIMEOUT     (0x0212)    /**< Message type for address timeouts */
+#define NG_NDP_MSG_NBR_SOL_RETRANS  (0x0213)    /**< Message type for multicast
+                                                 *   neighbor solicitation retransmissions */
+#define NG_NDP_MSG_NC_STATE_TIMEOUT (0x0214)    /**< Message type for neighbor cache state timeouts */
+
+/**
+ * @{
+ * @name    Node constants
+ * @see     <a href="https://tools.ietf.org/html/rfc4861#section-10">
+ *              RFC 4861, section 10
+ *          </a>
+ */
+/**
+ * @brief   Maximum number of unanswered multicast neighbor solicitations
+ *          before address resolution is considered failed.
+ */
+#define NG_NDP_MAX_MC_NBR_SOL_NUMOF (3U)
+
+/**
+ * @brief   Maximum number of unanswered unicast neighbor solicitations before
+ *          an address is considered unreachable.
+ */
+#define NG_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 NG_NDP_MAX_AC_TGT_DELAY     (1U)
+
+/**
+ * @brief   Maximum number of unsolicited neighbor advertisements before on
+ *          link-layer address change.
+ */
+#define NG_NDP_MAX_NBR_ADV_NUMOF    (3U)
+
+/**
+ * @brief   Base value in mircoseconds for computing randomised
+ *          reachable time.
+ */
+#define NG_NDP_REACH_TIME           (30U * SEC_IN_USEC)
+
+/**
+ * @brief   Time in mircoseconds between retransmissions of neighbor
+ *          solicitations to a neighbor.
+ */
+#define NG_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 NG_NDP_FIRST_PROBE_DELAY    (5U)
+
+/**
+ * @brief   Lower bound for randomised reachable time calculation.
+ */
+#define NG_NDP_MIN_RAND             (5U)
+
+/**
+ * @brief   Upper bound for randomised reachable time calculation.
+ */
+#define NG_NDP_MAX_RAND             (15U)
+/**
+ * @}
+ */
+
+/**
+ * @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 ng_ndp_nbr_sol_handle(kernel_pid_t iface, ng_pktsnip_t *pkt,
+                           ng_ipv6_hdr_t *ipv6, ng_ndp_nbr_sol_t *nbr_sol,
+                           size_t icmpv6_size);
+
+/**
+ * @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_adv       The neighbor advertisement in @p pkt.
+ * @param[in] icmpv6_size   The overall size of the neighbor solicitation
+ */
+void ng_ndp_nbr_adv_handle(kernel_pid_t iface, ng_pktsnip_t *pkt,
+                           ng_ipv6_hdr_t *ipv6, ng_ndp_nbr_adv_t *nbr_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 NG_IPV6_NC_STATE_INCOMPLETE or
+ *                          @ref NG_IPV6_NC_STATE_PROBE.
+ */
+void ng_ndp_retrans_nbr_sol(ng_ipv6_nc_t *nc_entry);
+
+/**
+ * @brief   Event handler for a neighbor cache state timeout.
+ *
+ * @param[in]   nc_entry    A neighbor cache entry.
+ */
+void ng_ndp_state_timeout(ng_ipv6_nc_t *nc_entry);
+
+/**
+ * @brief   NDP interface initialization.
+ *
+ * @param[in] iface     An IPv6 interface descriptor. Must not be NULL.
+ */
+void ng_ndp_netif_add(ng_ipv6_netif_t *iface);
+
+/**
+ * @brief   NDP interface removal.
+ *
+ * @param[in] iface     An IPv6 interface descriptor. Must not be NULL.
+ */
+void ng_ndp_netif_remove(ng_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 ng_ndp_next_hop_l2addr(uint8_t *l2addr, uint8_t *l2addr_len,
+                                    kernel_pid_t iface, ng_ipv6_addr_t *dst,
+                                    ng_pktsnip_t *pkt);
+
+/**
+ * @brief   Builds a neighbor solicitation message for sending.
+ *
+ * @see <a href="https://tools.ietf.org/html/rfc4861#section-4.3">
+ *          RFC 4861, section 4.3
+ *      </a>
+ *
+ * @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.
+ */
+ng_pktsnip_t *ng_ndp_nbr_sol_build(ng_ipv6_addr_t *tgt, ng_pktsnip_t *options);
+
+/**
+ * @brief   Builds a neighbor advertisement message for sending.
+ *
+ * @see <a href="https://tools.ietf.org/html/rfc4861#section-4.4">
+ *          RFC 4861, section 4.4
+ *      </a>
+ *
+ * @param[in] flags     Flags as defined above.
+ *                      @ref NG_NDP_NBR_ADV_FLAGS_R == 1 indicates, that the
+ *                      sender is a router,
+ *                      @ref NG_NDP_NBR_ADV_FLAGS_S == 1 indicates that the
+ *                      advertisement was sent in response to a neighbor
+ *                      solicitation,
+ *                      @ref NG_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 addres 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.
+ */
+ng_pktsnip_t *ng_ndp_nbr_adv_build(uint8_t flags, ng_ipv6_addr_t *tgt,
+                                   ng_pktsnip_t *options);
+
+/**
+ * @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
+ */
+ng_pktsnip_t *ng_ndp_opt_build(uint8_t type, size_t size, ng_pktsnip_t *next);
+
+/**
+ * @brief   Builds the source link-layer address option.
+ *
+ * @see <a href="https://tools.ietf.org/html/rfc4861#section-4.6.1">
+ *          RFC 4861, section 4.6.1
+ *      </a>
+ *
+ * @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
+ */
+ng_pktsnip_t *ng_ndp_opt_sl2a_build(const uint8_t *l2addr, uint8_t l2addr_len,
+                                    ng_pktsnip_t *next);
+
+/**
+ * @brief   Builds the target link-layer address option.
+ *
+ * @see <a href="https://tools.ietf.org/html/rfc4861#section-4.6.1">
+ *          RFC 4861, section 4.6.1
+ *      </a>
+ *
+ * @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
+ */
+ng_pktsnip_t *ng_ndp_opt_tl2a_build(const uint8_t *l2addr, uint8_t l2addr_len,
+                                    ng_pktsnip_t *next);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NG_NDP_H_ */
+/**
+ * @}
+ */