gnrc_sixlowpan_nd: initial import

Makefile.dep

@@ -52,6 +52,7 @@ endif
 ifneq (,$(filter gnrc_sixlowpan_default,$(USEMODULE)))
   USEMODULE += gnrc_ipv6_default
   USEMODULE += gnrc_sixlowpan
+  USEMODULE += gnrc_sixlowpan_nd
   USEMODULE += gnrc_sixlowpan_frag
   USEMODULE += gnrc_sixlowpan_iphc
 endif
@@ -77,10 +78,24 @@ ifneq (,$(filter gnrc_sixlowpan_ctx,$(USEMODULE)))
   USEMODULE += vtimer
 endif
 
+ifneq (,$(filter gnrc_sixlowpan_nd,$(USEMODULE)))
+  USEMODULE += gnrc_ndp
+  USEMODULE += gnrc_ndp_internal
+  USEMODULE += gnrc_sixlowpan_ctx
+  USEMODULE += random
+  USEMODULE += vtimer
+endif
+
 ifneq (,$(filter gnrc_ipv6_default,$(USEMODULE)))
   USEMODULE += gnrc_ipv6
   USEMODULE += gnrc_icmpv6
-  USEMODULE += gnrc_ndp_host
+  ifeq (1,$(GNRC_NETIF_NUMOF))
+    ifeq (,$(filter gnrc_sixlowpan_nd,$(USEMODULE)))
+      USEMODULE += gnrc_ndp_host
+    endif
+  else
+    USEMODULE += gnrc_ndp_host
+  endif
 endif
 
 ifneq (,$(filter gnrc_ipv6_router_default,$(USEMODULE)))

sys/include/net/gnrc/sixlowpan/nd.h

+/*
+ * Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
+ *
+ * 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_sixlowpan_nd 6LoWPAN neighbor discovery
+ * @ingroup     net_gnrc_sixlowpan
+ * @brief       Neighbor Discovery Optimization for 6LoWPAN
+ * @see         <a href="https://tools.ietf.org/html/rfc6775">
+ *                  RFC 6775
+ *              </a>
+ * @{
+ *
+ * @file
+ * @brief   General 6LoWPAN ND definitions
+ *
+ * @author  Martine Lenders <mlenders@inf.fu-berlin.de>
+ */
+#ifndef GNRC_SIXLOWPAN_ND_H_
+#define GNRC_SIXLOWPAN_ND_H_
+
+#include <stdint.h>
+
+#include "kernel_types.h"
+#include "net/gnrc/ipv6/nc.h"
+#include "net/gnrc/ipv6/netif.h"
+#include "net/ipv6/addr.h"
+#include "net/ndp.h"
+#include "net/sixlowpan/nd.h"
+#include "timex.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Message type for next multicast router solicitation.
+ */
+#define GNRC_SIXLOWPAN_ND_MSG_MC_RTR_SOL    (0x0220)
+
+/**
+ * @brief   Message type for next unicast router solicitation.
+ */
+#define GNRC_SIXLOWPAN_ND_MSG_UC_RTR_SOL    (0x0221)
+
+/**
+ * @brief   Message type for removing 6LoWPAN contexts.
+ */
+#define GNRC_SIXLOWPAN_ND_MSG_DELETE_CTX    (0x0222)
+
+#ifndef GNRC_SIXLOWPAN_ND_AR_LTIME
+/**
+ * @brief   Registration lifetime in minutes for the address registration option
+ *
+ * This value should be adapted to the devices power-lifecycle so that it is greater than the
+ * time the device spends sleeping.
+ *
+ * @see <a href="https://tools.ietf.org/html/rfc6775#section-5.8.1">
+ *          RFC 6775, section 5.8.1
+ *      </a>
+ */
+#define GNRC_SIXLOWPAN_ND_AR_LTIME          (15U)
+#endif
+
+/**
+ * @name    Host constants
+ * @{
+ * @see     <a href="https://tools.ietf.org/html/rfc6775#section-9">
+ *              RFC 6775, section 9
+ *          </a>
+ */
+#define GNRC_SIXLOWPAN_ND_RTR_SOL_INT       (10U)   /**< replacement value (in seconds) for
+                                                     *   @ref GNRC_NDP_MAX_RTR_SOL_INT */
+#define GNRC_SIXLOWPAN_ND_MAX_RTR_SOL_INT   (60U)   /**< retransmission increment for exponential
+                                                     *   backoff of subsequent RS */
+/** @} */
+
+/**
+ * @brief   Initializes 6LoWPAN neighbor discovery for the interface.
+ * @pre     @p iface->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN
+ * @param[in] iface An IPv6 interface.
+ */
+void gnrc_sixlowpan_nd_init(gnrc_ipv6_netif_t *iface);
+
+/**
+ * @brief   Multicasts a router solicitation over @p iface
+ * @pre     @p iface->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN
+ * @param[in] iface An IPv6 interface.
+ */
+void gnrc_sixlowpan_nd_mc_rtr_sol(gnrc_ipv6_netif_t *iface);
+
+/**
+ * @brief   Unicasts a router solicitation to the neighbor represented by @p nce
+ * @pre     @p nce->iface is an IPv6 interface and @ref GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN is set
+ *          in its flags.
+ * @param[in] nce   The neighbor to send the router solicitation to.
+ */
+void gnrc_sixlowpan_nd_uc_rtr_sol(gnrc_ipv6_nc_t *nce);
+
+/**
+ * @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.
+ *
+ * @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_sixlowpan_nd_next_hop_l2addr(uint8_t *l2addr, uint8_t *l2addr_len,
+                                               kernel_pid_t iface, ipv6_addr_t *dst);
+
+/**
+ * @brief   Reschedules the next router advertisement for a neighboring router.
+ *
+ * @pre nce != NULL && sec_delay != 0U
+ *
+ * @param[in] nce       Neighbor cache entry representing the neighboring router.
+ * @param[in] sec_delay The delay for the next router solicitation in seconds.
+ */
+void gnrc_sixlowpan_nd_rtr_sol_reschedule(gnrc_ipv6_nc_t *nce, uint32_t sec_delay);
+
+/**
+ * @brief   Builds the address registration option.
+ *
+ * @param[in] status    Status for the ARO.
+ * @param[in] ltime     Registration lifetime for the ARO.
+ * @param[in] eui64     The EUI-64 for the ARO
+ * @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_sixlowpan_nd_opt_ar_build(uint8_t status, uint16_t ltime, eui64_t *eui64,
+                                               gnrc_pktsnip_t *next);
+
+/**
+ * @brief   Handles address registration option.
+ *
+ * @param[in] iface         The interface the ARO was received on.
+ * @param[in] ipv6          The IPv6 header the ARO was received in.
+ * @param[in] icmpv6_type   Message type of the ICMPv6 message that contained.
+ *                          this message.
+ * @param[in] ar_opt        The address registration option.
+ * @param[in] sl2a          The link-layer source address contained in SL2A accompanying this
+ *                          option. May be NULL for icmpv6_type == ICMPV6_NBR_ADV.
+ * @param[in] sl2a_len      Length of @p sl2a. May be 0 if sl2a == NULL.
+ *
+ * @return  Status for the ARO in the replying NA (always 0 if icmpv6_type == ICMPV6_NBR_ADV).
+ */
+uint8_t gnrc_sixlowpan_nd_opt_ar_handle(kernel_pid_t iface, ipv6_hdr_t *ipv6,
+                                        uint8_t icmpv6_type, sixlowpan_nd_opt_ar_t *ar_opt,
+                                        uint8_t *sl2a, size_t sl2a_len);
+
+/**
+ * @brief   Handles 6LoWPAN context option.
+ *
+ * @param[in] icmpv6_type   Message type of the ICMPv6 message that contained.
+ *                          this message.
+ * @param[in] ctx_opt       The 6LoWPAN context option.
+ *
+ * @return  true, when 6LoWPAN context option was correct.
+ * @return  false, when it was incorrect.
+ */
+bool gnrc_sixlowpan_nd_opt_6ctx_handle(uint8_t icmpv6_type, sixlowpan_nd_opt_6ctx_t *ctx_opt);
+
+/**
+ * @brief   Handles registration calls after node-wakeup.
+ *
+ * @see     <a href="https://tools.ietf.org/html/rfc6775#section-5.8.2">
+ *              RFC 6776, section 5.8.2
+ *          </a>
+ */
+void gnrc_sixlowpan_nd_wakeup(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GNRC_SIXLOWPAN_ND_H_ */
+/** @} */

sys/net/gnrc/Makefile

@@ -79,6 +79,9 @@ endif
 ifneq (,$(filter gnrc_sixlowpan_iphc,$(USEMODULE)))
     DIRS += network_layer/sixlowpan/iphc
 endif
+ifneq (,$(filter gnrc_sixlowpan_nd,$(USEMODULE)))
+    DIRS += network_layer/sixlowpan/nd
+endif
 ifneq (,$(filter gnrc_sixlowpan_netif,$(USEMODULE)))
     DIRS += network_layer/sixlowpan/netif
 endif

sys/net/gnrc/network_layer/sixlowpan/nd/Makefile

+MODULE = gnrc_sixlowpan_nd
+
+include $(RIOTBASE)/Makefile.base

sys/net/gnrc/network_layer/sixlowpan/nd/gnrc_sixlowpan_nd.c

+/*
+ * Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
+ *
+ * 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
+ */
+
+#include "net/eui64.h"
+#include "net/gnrc/ipv6.h"
+#include "net/gnrc/ndp.h"
+#include "net/gnrc/ndp/internal.h"
+#include "net/gnrc/netif.h"
+#include "net/gnrc/sixlowpan.h"
+#include "net/gnrc/sixlowpan/ctx.h"
+#include "random.h"
+#include "timex.h"
+
+#include "net/gnrc/sixlowpan/nd.h"
+
+#define ENABLE_DEBUG (0)
+#include "debug.h"
+
+static inline void _rtr_sol_reschedule(gnrc_ipv6_netif_t *iface, uint32_t sec_delay)
+{
+    vtimer_remove(&iface->rtr_sol_timer);
+    vtimer_set_msg(&iface->rtr_sol_timer, timex_set(sec_delay, 0), gnrc_ipv6_pid,
+                   GNRC_SIXLOWPAN_ND_MSG_MC_RTR_SOL, iface);
+}
+
+static inline uint32_t _binary_exp_backoff(uint32_t base_sec, unsigned int exp)
+{
+    return genrand_uint32_range(0, (1 << exp) - 1) * base_sec;
+}
+
+static inline void _revert_iid(uint8_t *iid)
+{
+    iid[0] ^= 0x02;
+}
+
+void gnrc_sixlowpan_nd_init(gnrc_ipv6_netif_t *iface)
+{
+    assert(iface->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN);
+    mutex_lock(&iface->mutex);
+    iface->rtr_sol_count = 0;   /* first will be send immediately */
+
+    DEBUG("6lo nd: retransmit multicast rtr sol in 10 sec\n");
+    _rtr_sol_reschedule(iface, GNRC_SIXLOWPAN_ND_RTR_SOL_INT);
+    mutex_unlock(&iface->mutex);
+    gnrc_ndp_internal_send_rtr_sol(iface->pid, NULL);
+}
+
+void gnrc_sixlowpan_nd_mc_rtr_sol(gnrc_ipv6_netif_t *iface)
+{
+    uint32_t interval;
+    assert(iface->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN);
+    mutex_lock(&iface->mutex);
+    if (iface->rtr_sol_count < GNRC_NDP_MAX_RTR_SOL_NUMOF) {
+        DEBUG("6lo nd: retransmit multicast rtr sol in 10 sec\n");
+        iface->rtr_sol_count++;
+        interval = GNRC_SIXLOWPAN_ND_RTR_SOL_INT;
+    }
+    else {
+        unsigned int exp = (unsigned int)(iface->rtr_sol_count - GNRC_NDP_MAX_RTR_SOL_NUMOF);
+        interval = _binary_exp_backoff(1, exp);
+        if (((1U << exp) - 1U) < GNRC_SIXLOWPAN_ND_MAX_RTR_SOL_INT) {
+            /* XXX Not sure if this is the correct interpretation of the truncation described in
+             * https://tools.ietf.org/html/rfc6775#section-5.3. In every source I've read the
+             * truncating value was the exponent, not the target value, so I'm very confused
+             * about this sentencing. Anyway, since 60 sec is a maximum value this should only
+             * affect the energy consumption of the implementation by sending the next RS too fast
+             * but not its interoperability. */
+            iface->rtr_sol_count++;
+        }
+
+        DEBUG("6lo nd: retransmit multicast rtr sol in %" PRIu32 " sec\n", interval);
+        iface->rtr_sol_count--;
+    }
+    _rtr_sol_reschedule(iface, interval);
+    mutex_unlock(&iface->mutex);
+    gnrc_ndp_internal_send_rtr_sol(iface->pid, NULL);
+}
+
+void gnrc_sixlowpan_nd_uc_rtr_sol(gnrc_ipv6_nc_t *nce)
+{
+    assert(gnrc_ipv6_netif_get(nce->iface)->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN);
+    /* neighbor is not a router anymore */
+    if (!(nce->flags & GNRC_IPV6_NC_IS_ROUTER) || ipv6_addr_is_unspecified(&nce->ipv6_addr)) {
+        /* and there are no routers anymore */
+        if (gnrc_ipv6_nc_get_next_router(NULL) == NULL) {
+            /* start search for routers */
+            gnrc_sixlowpan_nd_init(gnrc_ipv6_netif_get(nce->iface));
+        }
+        /* otherwise ignore this call */
+        return;
+    }
+    /* next RS is rescheduled by RA handle function */
+    gnrc_ndp_internal_send_rtr_sol(nce->iface, &nce->ipv6_addr);
+}
+
+kernel_pid_t gnrc_sixlowpan_nd_next_hop_l2addr(uint8_t *l2addr, uint8_t *l2addr_len,
+                                               kernel_pid_t iface, ipv6_addr_t *dst)
+{
+    ipv6_addr_t *next_hop = NULL;
+    gnrc_ipv6_nc_t *nc_entry = NULL;
+
+#ifdef MODULE_GNRC_IPV6_EXT_RH
+    ipv6_hdr_t *hdr;
+    gnrc_pktsnip_t *ipv6;
+    LL_SEARCH_SCALAR(pkt, ipv6, type, GNRC_NETTYPE_IPV6);
+    assert(ipv6);
+    hdr = ipv6->data;
+    next_hop = ipv6_ext_rh_next_hop(hdr);
+#endif
+#ifdef MODULE_FIB
+    ipv6_addr_t next_hop_actual;    /* FIB copies address into this variable */
+    /* don't look-up link local addresses in FIB */
+    if ((next_hop == NULL) && !ipv6_addr_is_link_local(dst)) {
+        size_t next_hop_size = sizeof(ipv6_addr_t);
+        uint32_t next_hop_flags = 0;
+        if ((next_hop == NULL) &&
+            (fib_get_next_hop(&gnrc_ipv6_fib_table, &iface, next_hop_actual.u8, &next_hop_size,
+                              &next_hop_flags, (uint8_t *)dst,
+                              sizeof(ipv6_addr_t), 0) >= 0) &&
+            (next_hop_size == sizeof(ipv6_addr_t))) {
+            next_hop = &next_hop_actual;
+        }
+    }
+#endif
+    /* next hop determination according to: https://tools.ietf.org/html/rfc6775#section-5.6 */
+    if ((next_hop == NULL) && ipv6_addr_is_link_local(dst)) {   /* prefix is "on-link" */
+        /* multicast is not handled here anyway so we don't need to check that */
+        next_hop = dst;
+    }
+    else if (next_hop == NULL) {                                /* prefix is off-link */
+        next_hop = gnrc_ndp_internal_default_router();
+    }
+
+    /* address resolution of next_hop: https://tools.ietf.org/html/rfc6775#section-5.7 */
+    if (ipv6_addr_is_link_local(next_hop)) {
+        kernel_pid_t ifs[GNRC_NETIF_NUMOF];
+        size_t ifnum = gnrc_netif_get(ifs);
+        /* we don't need address resolution, the EUI-64 is in next_hop's IID */
+        *l2addr_len = sizeof(eui64_t);
+        memcpy(l2addr, &next_hop->u8[8], sizeof(eui64_t));
+        _revert_iid(l2addr);
+        if (iface == KERNEL_PID_UNDEF) {
+            for (unsigned i = 0; i < ifnum; i++) {
+                gnrc_ipv6_netif_t *ipv6_if = gnrc_ipv6_netif_get(ifs[i]);
+                if ((ipv6_if != NULL) && (ipv6_if->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN)) {
+                    /* always take the first 6LoWPAN interface we can find */
+                    return ifs[i];
+                }
+            }
+        }
+        return iface;
+    }
+    else {
+        nc_entry = gnrc_ipv6_nc_get(iface, next_hop);
+        if ((nc_entry == NULL) || (!gnrc_ipv6_nc_is_reachable(nc_entry))) {
+            return KERNEL_PID_UNDEF;
+        }
+        if (nc_entry->l2_addr_len > 0) {
+            memcpy(l2addr, nc_entry->l2_addr, nc_entry->l2_addr_len);
+        }
+        *l2addr_len = nc_entry->l2_addr_len;
+        return nc_entry->iface;
+    }
+}
+
+void gnrc_sixlowpan_nd_rtr_sol_reschedule(gnrc_ipv6_nc_t *nce, uint32_t sec_delay)
+{
+    assert(nce != NULL);
+    assert(sec_delay != 0U);
+    vtimer_remove(&nce->rtr_sol_timer);
+    vtimer_set_msg(&nce->rtr_sol_timer, timex_set(sec_delay, 0), gnrc_ipv6_pid,
+                   GNRC_SIXLOWPAN_ND_MSG_MC_RTR_SOL, nce);
+}
+
+gnrc_pktsnip_t *gnrc_sixlowpan_nd_opt_ar_build(uint8_t status, uint16_t ltime, eui64_t *eui64,
+                                               gnrc_pktsnip_t *next)
+{
+    gnrc_pktsnip_t *pkt = gnrc_ndp_opt_build(NDP_OPT_AR, sizeof(sixlowpan_nd_opt_ar_t), next);
+
+    if (pkt != NULL) {
+        sixlowpan_nd_opt_ar_t *ar_opt = pkt->data;
+        ar_opt->status = status;
+        ar_opt->resv[0] = ar_opt->resv[1] = ar_opt->resv[2] = 0;
+        ar_opt->ltime = byteorder_htons(ltime);
+        memcpy(&ar_opt->eui64, eui64, sizeof(eui64_t));
+    }
+
+    return pkt;
+}
+
+uint8_t gnrc_sixlowpan_nd_opt_ar_handle(kernel_pid_t iface, ipv6_hdr_t *ipv6, uint8_t icmpv6_type,
+                                        sixlowpan_nd_opt_ar_t *ar_opt, uint8_t *sl2a,
+                                        size_t sl2a_len)
+{
+    eui64_t eui64;
+    gnrc_ipv6_netif_t *ipv6_iface;
+    gnrc_ipv6_nc_t *nc_entry;
+    (void)sl2a;
+    (void)sl2a_len;
+    if (ar_opt->len != SIXLOWPAN_ND_OPT_AR_LEN) {
+        /* discard silently: see https://tools.ietf.org/html/rfc6775#section-5.5.2 */
+        return 0;
+    }
+    if (gnrc_netapi_get(iface, NETOPT_ADDRESS_LONG, 0, &eui64,
+                        sizeof(eui64)) < 0) {
+        /* discard silently: see https://tools.ietf.org/html/rfc6775#section-5.5.2 */
+        return 0;
+    }
+    ipv6_iface = gnrc_ipv6_netif_get(iface);
+    nc_entry = gnrc_ipv6_nc_get(iface, &ipv6->src);
+    switch (icmpv6_type) {
+        case ICMPV6_NBR_ADV:
+            if (!(ipv6_iface->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN)) {
+                DEBUG("6lo nd: interface not a 6LoWPAN interface\n");
+                return 0;
+            }
+            if (eui64.uint64.u64 != ar_opt->eui64.uint64.u64) {
+                /* discard silently: see https://tools.ietf.org/html/rfc6775#section-5.5.2 */
+                return 0;
+            }
+            switch (ar_opt->status) {
+                case SIXLOWPAN_ND_STATUS_SUCCESS:
+                    DEBUG("6lo nd: address registration successful\n");
+                    mutex_lock(&ipv6_iface->mutex);
+                    vtimer_remove(&nc_entry->nbr_sol_timer);
+                    vtimer_set_msg(&nc_entry->nbr_sol_timer, ipv6_iface->retrans_timer,
+                                   gnrc_ipv6_pid, GNRC_NDP_MSG_NBR_SOL_RETRANS, nc_entry);
+                    mutex_unlock(&ipv6_iface->mutex);
+                    break;
+                case SIXLOWPAN_ND_STATUS_DUP:
+                    DEBUG("6lo nd: address registration determined duplicated\n");
+                    /* TODO: handle DAD failed case */
+                    gnrc_ipv6_netif_remove_addr(iface, &ipv6->dst);
+                    /* address should not be used anymore */
+                    break;
+                case SIXLOWPAN_ND_STATUS_NC_FULL:
+                    DEBUG("6lo nd: neighbor cache on router is full\n");
+                    gnrc_ipv6_nc_remove(iface, &ipv6->src);
+                    /* try to find another router */
+                    gnrc_sixlowpan_nd_init(ipv6_iface);
+                    break;
+                default:
+                    DEBUG("6lo nd: unknown status for registration received\n");
+                    break;
+            }
+        default:
+            break;
+    }
+
+    return 0;
+}
+
+bool gnrc_sixlowpan_nd_opt_6ctx_handle(uint8_t icmpv6_type, sixlowpan_nd_opt_6ctx_t *ctx_opt)
+{
+    if (((ctx_opt->ctx_len < 64) && (ctx_opt->len != 2)) ||
+        ((ctx_opt->ctx_len >= 64) && (ctx_opt->len != 3))) {
+        DEBUG("6lo nd: invalid 6LoWPAN context option received\n");
+        return false;
+    }
+    if (icmpv6_type != ICMPV6_RTR_ADV) {
+        /* discard silently */
+        return true;
+    }
+    /* don't care for result */
+    gnrc_sixlowpan_ctx_update(sixlowpan_nd_opt_6ctx_get_cid(ctx_opt), (ipv6_addr_t *)(ctx_opt + 1),
+                              ctx_opt->ctx_len, byteorder_ntohs(ctx_opt->ltime),
+                              sixlowpan_nd_opt_6ctx_is_comp(ctx_opt));
+    return true;
+}
+
+void gnrc_sixlowpan_nd_wakeup(void)
+{
+    gnrc_ipv6_nc_t *router = gnrc_ipv6_nc_get_next_router(NULL);
+    while (router) {
+        timex_t t = { 0, GNRC_NDP_RETRANS_TIMER };
+        vtimer_remove(&router->rtr_sol_timer);
+        gnrc_sixlowpan_nd_uc_rtr_sol(router);
+        gnrc_ndp_internal_send_nbr_sol(router->iface, &router->ipv6_addr, &router->ipv6_addr);
+        vtimer_remove(&router->nbr_sol_timer);
+        vtimer_set_msg(&router->nbr_sol_timer, t, gnrc_ipv6_pid, GNRC_NDP_MSG_NBR_SOL_RETRANS,
+                       router);
+    }
+}
+
+/** @} */