Removed NUD messages from registered children

When we would send a NUD to check link status we skip it if there is a
valid ARO registration for that neighbour

Author: Mika Tervonen

source/6LoWPAN/ws/ws_bootstrap.c

@@ -1629,6 +1629,8 @@ static void ws_neighbor_entry_remove_notify(mac_neighbor_table_entry_t *entry_pt
 static bool ws_neighbor_entry_nud_notify(mac_neighbor_table_entry_t *entry_ptr, void *user_data)
 {
     uint32_t time_from_start = entry_ptr->link_lifetime - entry_ptr->lifetime;
+    uint8_t ll_address[16];
+    bool nud_proces = false;
     bool activate_nud = false;
     protocol_interface_info_entry_t *cur = user_data;
 
@@ -1639,17 +1641,22 @@ static bool ws_neighbor_entry_nud_notify(mac_neighbor_table_entry_t *entry_ptr,
         return false;
     }
 
-    uint8_t ll_address[16];
-    bool nud_proces = false;
+    ws_bootsrap_create_ll_address(ll_address, entry_ptr->mac64);
+
     if (time_from_start > WS_NEIGHBOR_NUD_TIMEOUT) {
 
-        ws_bootsrap_create_ll_address(ll_address, entry_ptr->mac64);
+        if (ipv6_neighbour_has_registered_by_eui64(&cur->ipv6_neighbour_cache, entry_ptr->mac64)) {
+            // This is our child with valid ARO registration Change link timeout to future we check at 2 minute intervals
+            entry_ptr->lifetime = entry_ptr->lifetime + 120;
+            if (entry_ptr->lifetime > entry_ptr->link_lifetime) {
+                entry_ptr->lifetime = entry_ptr->link_lifetime;
+            }
+            return false;
+        }
 
         if (!rpl_control_is_dodag_parent_candidate(cur, ll_address, WS_NEIGHBOUR_MAX_CANDIDATE_PROBE)) {
-            if (!ipv6_neighbour_has_registered_by_eui64(&cur->ipv6_neighbour_cache, entry_ptr->mac64)) {
-                //NUD Not needed for if neighbour is not child or parent candidate
-                return false;
-            }
+            //NUD Not needed for if neighbour is not parent candidate
+            return false;
         }
 
         if (time_from_start > WS_NEIGHBOR_NUD_TIMEOUT * 1.5) {