gnrc_ipv6_nib: add full RFC4862 DAD support

Parts of [RFC4862] were already implemented when NDP via the NIB was
first implemented. This change just includes the DAD portion of
[RFC4862]. This should be enough to make RIOT fully RFC4862 compliant.

[RFC4862]: https://tools.ietf.org/html/rfc4862

sys/include/net/gnrc/ipv6/nib.h

@@ -202,6 +202,26 @@ extern "C" {
  * @note Only handled with @ref GNRC_IPV6_NIB_CONF_ROUTER != 0
  */
 #define GNRC_IPV6_NIB_ROUTE_TIMEOUT (0x4fd0U)
+
+/**
+ * @brief Perform DAD event.
+ *
+ * This message type is for performing DAD for a given address. The expected
+ * message context is a TENTATIVE IPv6 address.
+ *
+ * @note Only handled with @ref GNRC_IPV6_NIB_CONF_SLAAC != 0
+ */
+#define GNRC_IPV6_NIB_DAD (0x4fd1U)
+
+/**
+ * @brief Validate a tentative address event.
+ *
+ * Moves a TENTATIVE address to VALID state. The expected message context is a
+ * TENTATIVE IPv6 address.
+ *
+ * @note Only handled with @ref GNRC_IPV6_NIB_CONF_SLAAC != 0
+ */
+#define GNRC_IPV6_NIB_VALID_ADDR (0x4fd2U)
 /** @} */
 
 /**

sys/include/net/gnrc/netif/ipv6.h

@@ -151,13 +151,14 @@ typedef struct {
  * and @ref net_gnrc_ipv6_nib "NIB"
  */
  evtimer_msg_event_t search_rtr;
-#if GNRC_IPV6_NIB_CONF_6LN || DOXYGEN
+#if GNRC_IPV6_NIB_CONF_6LN || GNRC_IPV6_NIB_CONF_SLAAC || DOXYGEN
  /**
  * @brief Timers for address re-registration
  *
  * @note Only available with module @ref net_gnrc_ipv6 "gnrc_ipv6" and
  * @ref net_gnrc_ipv6_nib "NIB" and if
- * @ref GNRC_IPV6_NIB_CONF_6LN != 0
+ * @ref GNRC_IPV6_NIB_CONF_6LN != 0 or
+ * @ref GNRC_IPV6_NIB_CONF_SLAAC != 0
  * @note Might also be usable in the later default SLAAC implementation
  * for NS retransmission timers.
  */

sys/net/gnrc/netif/gnrc_netif.c

@@ -21,6 +21,7 @@
 #include "net/gnrc.h"
 #ifdef MODULE_GNRC_IPV6_NIB
 #include "net/gnrc/ipv6/nib.h"
+#include "net/gnrc/ipv6.h"
 #endif /* MODULE_GNRC_IPV6_NIB */
 #ifdef MODULE_NETSTATS_IPV6
 #include "net/netstats.h"
@@ -589,8 +590,13 @@ int gnrc_netif_ipv6_addr_add_internal(gnrc_netif_t *netif,
  }
  }
 #if GNRC_IPV6_NIB_CONF_SLAAC
- else {
- /* TODO: send out NS to solicited nodes for DAD probing */
+ else if (!gnrc_netif_is_6ln(netif)) {
+ /* cast to remove const qualifier (will still be used NIB internally as
+ * const) */
+ msg_t msg = { .type = GNRC_IPV6_NIB_DAD,
+ .content = { .ptr = &netif->ipv6.addrs[idx] } };
+
+ msg_send(&msg, gnrc_ipv6_pid);
  }
 #endif
 #else
@@ -961,8 +967,7 @@ static int _create_candidate_set(const gnrc_netif_t *netif,
  * be included in a candidate set."
  */
  if ((netif->ipv6.addrs_flags[i] == 0) ||
- (gnrc_netif_ipv6_addr_get_state(netif, i) ==
- GNRC_NETIF_IPV6_ADDRS_FLAGS_STATE_TENTATIVE)) {
+ gnrc_netif_ipv6_addr_dad_trans(netif, i)) {
  continue;
  }
  /* Check if we only want link local addresses */

sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c

@@ -297,7 +297,8 @@ static void *_event_loop(void *args)
  case GNRC_IPV6_NIB_RTR_TIMEOUT:
  case GNRC_IPV6_NIB_RECALC_REACH_TIME:
  case GNRC_IPV6_NIB_REREG_ADDRESS:
- case GNRC_IPV6_NIB_ROUTE_TIMEOUT:
+ case GNRC_IPV6_NIB_DAD:
+ case GNRC_IPV6_NIB_VALID_ADDR:
  DEBUG("ipv6: NIB timer event received\n");
  gnrc_ipv6_nib_handle_timer_event(msg.content.ptr, msg.type);
  break;

sys/net/gnrc/network_layer/ipv6/nib/_nib-slaac.c

@@ -0,0 +1,205 @@
+/*
+ * Copyright (C) 2018 Freie Universität Berlin
+ *
+ * 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.
+ */
+
+/**
+ * @{
+ *
+ * @file
+ * @author Martine Lenders <m.lenders@fu-berlin.de>
+ */
+
+#include <stdbool.h>
+
+#include "luid.h"
+#include "net/gnrc/netif/internal.h"
+
+#include "_nib-6ln.h"
+#include "_nib-arsm.h"
+
+#define ENABLE_DEBUG (0)
+#include "debug.h"
+
+static char addr_str[IPV6_ADDR_MAX_STR_LEN];
+
+#if GNRC_IPV6_NIB_CONF_6LN || GNRC_IPV6_NIB_CONF_SLAAC
+void _auto_configure_addr(gnrc_netif_t *netif, const ipv6_addr_t *pfx,
+ uint8_t pfx_len)
+{
+ ipv6_addr_t addr = IPV6_ADDR_UNSPECIFIED;
+ int idx;
+ uint8_t flags = GNRC_NETIF_IPV6_ADDRS_FLAGS_STATE_TENTATIVE;
+
+ DEBUG("nib: add address based on %s/%u automatically to interface %u\n",
+ ipv6_addr_to_str(addr_str, pfx, sizeof(addr_str)),
+ pfx_len, netif->pid);
+#if GNRC_IPV6_NIB_CONF_6LN
+ bool new_address = false;
+#endif /* GNRC_IPV6_NIB_CONF_6LN */
+ gnrc_netif_ipv6_get_iid(netif, (eui64_t *)&addr.u64[1]);
+ ipv6_addr_init_prefix(&addr, pfx, pfx_len);
+ if ((idx = gnrc_netif_ipv6_addr_idx(netif, &addr)) < 0) {
+ if ((idx = gnrc_netif_ipv6_addr_add_internal(netif, &addr, pfx_len,
+ flags)) < 0) {
+ DEBUG("nib: Can't add link-local address on interface %u\n",
+ netif->pid);
+ return;
+ }
+#if GNRC_IPV6_NIB_CONF_6LN
+ new_address = true;
+#endif /* GNRC_IPV6_NIB_CONF_6LN */
+ }
+
+#if GNRC_IPV6_NIB_CONF_6LN
+ /* mark link-local addresses as valid on 6LN */
+ if (gnrc_netif_is_6ln(netif) && ipv6_addr_is_link_local(pfx)) {
+ /* don't do this beforehand or risk a deadlock:
+ * - gnrc_netif_ipv6_addr_add_internal() adds VALID (i.e. manually configured
+ * addresses to the prefix list locking the NIB's mutex which is already
+ * locked here) */
+ netif->ipv6.addrs_flags[idx] &= ~GNRC_NETIF_IPV6_ADDRS_FLAGS_STATE_MASK;
+ netif->ipv6.addrs_flags[idx] |= GNRC_NETIF_IPV6_ADDRS_FLAGS_STATE_VALID;
+ }
+#endif /* GNRC_IPV6_NIB_CONF_6LN */
+#if GNRC_IPV6_NIB_CONF_6LN
+ if (new_address && gnrc_netif_is_6ln(netif) &&
+ !gnrc_netif_is_6lbr(netif)) {
+ _handle_rereg_address(&netif->ipv6.addrs[idx]);
+ }
+#else /* GNRC_IPV6_NIB_CONF_6LN */
+ (void)idx;
+#endif /* GNRC_IPV6_NIB_CONF_6LN */
+}
+#endif /* GNRC_IPV6_NIB_CONF_6LN || GNRC_IPV6_NIB_CONF_SLAAC */
+
+#if GNRC_IPV6_NIB_CONF_SLAAC
+static bool _try_l2addr_reconfiguration(gnrc_netif_t *netif)
+{
+ uint8_t hwaddr[GNRC_NETIF_L2ADDR_MAXLEN];
+ uint16_t hwaddr_len;
+
+ if (gnrc_netapi_get(netif->pid, NETOPT_SRC_LEN, 0, &hwaddr_len,
+ sizeof(hwaddr_len)) < 0) {
+ return false;
+ }
+ luid_get(hwaddr, hwaddr_len);
+#if GNRC_IPV6_NIB_CONF_6LN
+ if (hwaddr_len == IEEE802154_LONG_ADDRESS_LEN) {
+ if (gnrc_netapi_set(netif->pid, NETOPT_ADDRESS_LONG, 0, hwaddr,
+ hwaddr_len) < 0) {
+ return false;
+ }
+ }
+ else
+#endif
+ if (gnrc_netapi_set(netif->pid, NETOPT_ADDRESS, 0, hwaddr,
+ hwaddr_len) < 0) {
+ return false;
+ }
+ return true;
+}
+
+static bool _try_addr_reconfiguration(gnrc_netif_t *netif)
+{
+ eui64_t orig_iid;
+ bool remove_old = false, hwaddr_reconf;
+
+ if (gnrc_netif_ipv6_get_iid(netif, &orig_iid) == 0) {
+ remove_old = true;
+ }
+ /* seize netif to netif thread since _try_l2addr_reconfiguration uses
+ * gnrc_netapi_get()/gnrc_netapi_set(). Since these are synchronous this is
+ * safe */
+ gnrc_netif_release(netif);
+ /* reacquire netif for IPv6 address reconfiguraton */
+ hwaddr_reconf = _try_l2addr_reconfiguration(netif);
+ gnrc_netif_acquire(netif);
+ if (hwaddr_reconf) {
+ if (remove_old) {
+ for (unsigned i = 0; i < GNRC_NETIF_IPV6_ADDRS_NUMOF; i++) {
+ ipv6_addr_t *addr = &netif->ipv6.addrs[i];
+ if (addr->u64[1].u64 == orig_iid.uint64.u64) {
+ gnrc_netif_ipv6_addr_remove_internal(netif, addr);
+ }
+ }
+ }
+ DEBUG("nib: Changed hardware address, due to DAD\n");
+ _auto_configure_addr(netif, &ipv6_addr_link_local_prefix, 64U);
+ }
+ return hwaddr_reconf;
+}
+
+void _remove_tentative_addr(gnrc_netif_t *netif, const ipv6_addr_t *addr)
+{
+ DEBUG("nib: other node has TENTATIVE address %s assigned "
+ "=> removing that address\n",
+ ipv6_addr_to_str(addr_str, addr, sizeof(addr_str)));
+ gnrc_netif_ipv6_addr_remove_internal(netif, addr);
+
+ if (!ipv6_addr_is_link_local(addr) ||
+ !_try_addr_reconfiguration(netif)) {
+ /* Cannot use target address as personal address and can
+ * not change hardware address to retry SLAAC => use purely
+ * DHCPv6 instead */
+ /* TODO: implement IA_NA for DHCPv6 */
+ /* then => tgt_netif->aac_mode = GNRC_NETIF_AAC_DHCP; */
+ DEBUG("nib: would set interface %i to DHCPv6, "
+ "but is not implemented yet", netif->pid);
+ }
+}
+
+static int _get_netif_state(gnrc_netif_t **netif, const ipv6_addr_t *addr)
+{
+ *netif = gnrc_netif_get_by_ipv6_addr(addr);
+ if (*netif != NULL) {
+ int idx;
+
+ gnrc_netif_acquire(*netif);
+ idx = gnrc_netif_ipv6_addr_idx(*netif, addr);
+ return ((idx >= 0) && gnrc_netif_ipv6_addr_dad_trans(*netif, idx)) ?
+ idx : -1;
+ }
+ return -1;
+}
+
+void _handle_dad(const ipv6_addr_t *addr)
+{
+ ipv6_addr_t sol_nodes;
+ gnrc_netif_t *netif = NULL;
+ int idx = _get_netif_state(&netif, addr);
+ if (idx >= 0) {
+ ipv6_addr_set_solicited_nodes(&sol_nodes, addr);
+ _snd_ns(addr, netif, &ipv6_addr_unspecified, &sol_nodes);
+ _evtimer_add((void *)addr, GNRC_IPV6_NIB_VALID_ADDR,
+ &netif->ipv6.addrs_timers[idx],
+ netif->ipv6.retrans_time);
+ }
+ if (netif != NULL) {
+ /* was acquired in `_get_netif_state()` */
+ gnrc_netif_release(netif);
+ }
+}
+
+void _handle_valid_addr(const ipv6_addr_t *addr)
+{
+ gnrc_netif_t *netif = NULL;
+ int idx = _get_netif_state(&netif, addr);
+
+ if (idx >= 0) {
+ netif->ipv6.addrs_flags[idx] &= ~GNRC_NETIF_IPV6_ADDRS_FLAGS_STATE_MASK;
+ netif->ipv6.addrs_flags[idx] |= GNRC_NETIF_IPV6_ADDRS_FLAGS_STATE_VALID;
+ }
+ if (netif != NULL) {
+ /* was acquired in `_get_netif_state()` */
+ gnrc_netif_release(netif);
+ }
+}
+#else /* GNRC_IPV6_NIB_CONF_SLAAC */
+typedef int dont_be_pedantic;
+#endif /* GNRC_IPV6_NIB_CONF_SLAAC */
+
+/** @} */

sys/net/gnrc/network_layer/ipv6/nib/_nib-slaac.h

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2018 Freie Universität Berlin
+ *
+ * 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.
+ */
+
+/**
+ * @ingroup net_gnrc_ipv6_nib
+ * @brief
+ * @{
+ *
+ * @file
+ * @brief Definions related to SLAAC functionality of the NIB
+ * @see @ref GNRC_IPV6_NIB_CONF_SLAAC
+ * @internal
+ *
+ * @author Martine Lenders <m.lenders@fu-berlin.de>
+ */
+#ifndef PRIV_NIB_SLAAC_H
+#define PRIV_NIB_SLAAC_H
+
+#include <stdint.h>
+
+#include "net/gnrc/ipv6/nib/conf.h"
+#include "net/gnrc/netif.h"
+#include "net/ipv6/addr.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if GNRC_IPV6_NIB_CONF_6LN || GNRC_IPV6_NIB_CONF_SLAAC || defined(DOXYGEN)
+/**
+ * @brief Auto-configures an address from a given prefix
+ *
+ * @param[in] netif The network interface the address should be added to.
+ * @param[in] pfx The prefix for the address.
+ * @param[in] pfx_len Length of @p pfx in bits.
+ */
+void _auto_configure_addr(gnrc_netif_t *netif, const ipv6_addr_t *pfx,
+ uint8_t pfx_len);
+#else /* GNRC_IPV6_NIB_CONF_6LN || GNRC_IPV6_NIB_CONF_SLAAC */
+#define _auto_configure_addr(netif, pfx, pfx_len) \
+ (void)netif; (void)pfx; (void)pfx_len;
+#endif /* GNRC_IPV6_NIB_CONF_6LN || GNRC_IPV6_NIB_CONF_SLAAC */
+#if GNRC_IPV6_NIB_CONF_SLAAC || defined(DOXYGE)
+/**
+ * @brief Removes a tentative address from the interface and tries to
+ * reconfigure a new address
+ *
+ * @param[in] netif The network interface the address is to be removed from.
+ * @param[in] addr The address to remove.
+ */
+void _remove_tentative_addr(gnrc_netif_t *netif, const ipv6_addr_t *addr);
+
+/**
+ * @brief Handle @ref GNRC_IPV6_NIB_DAD event
+ *
+ * @param[in] addr A TENTATIVE address.
+ */
+void _handle_dad(const ipv6_addr_t *addr);
+
+/**
+ * @brief Handle @ref GNRC_IPV6_NIB_VALID_ADDR event
+ *
+ * @param[in] addr A TENTATIVE address.
+ */
+void _handle_valid_addr(const ipv6_addr_t *addr);
+#else /* GNRC_IPV6_NIB_CONF_SLAAC */
+#define _remove_tentative_addr(netif, addr) \
+ (void)netif; (void)addr
+#define _handle_dad(addr) (void)addr
+#define _handle_valid_addr(addr) (void)addr
+#endif /* GNRC_IPV6_NIB_CONF_SLAAC */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PRIV_NIB_SLAAC_H */
+/** @} */