Merge pull request #4284 from authmillenon/gnrc_ipv6/enh/addr-res-without-nd

gnrc_ipv6: get l2addr from NC if no ND present

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

@@ -540,6 +540,15 @@ static inline kernel_pid_t _next_hop_l2addr(uint8_t *l2addr, uint8_t *l2addr_len
 #endif
 #if defined(MODULE_GNRC_NDP_NODE)
     found_iface = gnrc_ndp_node_next_hop_l2addr(l2addr, l2addr_len, iface, dst, pkt);
+#elif !defined(MODULE_GNRC_SIXLOWPAN_ND) && defined(MODULE_GNRC_IPV6_NC)
+    (void)pkt;
+    gnrc_ipv6_nc_t *nc = gnrc_ipv6_nc_get(iface, dst);
+    if ((nc == NULL) || !gnrc_ipv6_nc_is_reachable(nc)) {
+        return KERNEL_PID_UNDEF;
+    }
+    found_iface = nc->iface;
+    *l2addr_len = nc->l2_addr_len;
+    memcpy(l2addr, nc->l2_addr, nc->l2_addr_len);
 #elif !defined(MODULE_GNRC_SIXLOWPAN_ND)
     found_iface = KERNEL_PID_UNDEF;
     (void)l2addr;