Clear network data from lost children

In some cases thread network data may contain data from children who
have changed parent but the network data still point to old parent.

-When original parent comes back to network then is must clean such data.
-If parent does not come back then network leader will detect parent loss and
clean network data from the parent and its children.

Author: Arto Kinnunen

source/6LoWPAN/Thread/thread_bootstrap.c

@@ -170,19 +170,19 @@ static void thread_neighbor_remove(int8_t interface_id, mle_neigh_table_entry_t
             else{
                 tr_debug("Delete REED Neighbor");
                 if (thread_is_router_addr(cur->short_adr)) {
-                tr_debug("Router Free");
-                thread_routing_remove_link(cur_interface, cur->short_adr);
+                    tr_debug("Router Free");
+                    thread_routing_remove_link(cur_interface, cur->short_adr);
                 }
             }
         }
         else if (thread_info(cur_interface)->thread_attached_state == THREAD_STATE_CONNECTED_ROUTER)
         {
-            tr_debug("Delete Router Neighbor");
+            tr_debug("Delete Router Neighbor %x", cur->short_adr);
             if (thread_is_router_addr(cur->short_adr)) {
-                tr_debug("Router Free");
+                tr_debug("Router free");
                 thread_routing_remove_link(cur_interface, cur->short_adr);
             } else if (thread_addr_is_child(mac_helper_mac16_address_get(cur_interface), cur->short_adr)) {
-                tr_debug("Child Free");
+                tr_debug("Child free");
                 /* 16-bit neighbour cache entries are mesh addresses, so remain potentially valid even if an
                  * MLE link fails. This is the only exception - if it was the link from us as a router to a
                  * child. That means that device must be off the mesh (at that 16-bit address, at least).
@@ -1163,6 +1163,8 @@ void thread_tasklet(arm_event_s *event)
                 thread_border_router_publish(cur->id);
             }
             thread_router_bootstrap_address_change_notify_send(cur);
+            // Validate network data after a short period
+            thread_border_router_resubmit_timer_set(cur->id, 5);
             break;
         case THREAD_ATTACH_ROUTER_ID_GET_FAIL:
             tr_debug_extra("Thread SM THREAD_ATTACH_ROUTER_ID_GET_FAIL");

source/6LoWPAN/Thread/thread_border_router_api.c

@@ -297,6 +297,64 @@ static bool thread_border_router_local_network_data_prefix_match(thread_network_
     return true;
 }
 
+static void thread_border_router_children_network_data_check_and_clean(uint8_t interface_id, uint16_t child_id)
+{
+    uint8_t addr16_buf[2];
+
+    if (thread_is_router_addr(child_id)) {
+        // Do not check routers
+        return;
+    }
+
+    common_write_16_bit(child_id, addr16_buf);
+
+    if (!mle_class_get_by_link_address(interface_id, addr16_buf, ADDR_802_15_4_SHORT)) {
+        // Child is not our child => network data contains data from lost children, remove it
+        tr_debug("Remove nwk data from lost child: %04x", child_id);
+        thread_management_client_network_data_unregister(interface_id, child_id);
+    }
+}
+
+static void thread_border_router_lost_children_nwk_data_validate(protocol_interface_info_entry_t *cur, uint16_t router_short_addr)
+{
+
+    tr_debug("thread_border_router_lost_children_nwk_data_validate() %x", router_short_addr);
+    if (!thread_is_router_addr(router_short_addr)) {
+        // not validating children nwk data
+        return;
+    }
+
+    thread_network_data_cache_entry_t *network_data = &cur->thread_info->networkDataStorage;
+
+    ns_list_foreach(thread_network_data_prefix_cache_entry_t, curLP, &network_data->localPrefixList) {
+        /* Go throgh all routes */
+        ns_list_foreach(thread_network_server_data_entry_t, curRoute, &curLP->routeList) {
+            if (thread_addr_is_child(router_short_addr, curRoute->routerID)) {
+                // Router children found
+                thread_border_router_children_network_data_check_and_clean(cur->id, curRoute->routerID);
+            }
+        }
+
+        /* Go through all BR's */
+        ns_list_foreach(thread_network_server_data_entry_t, curBR, &curLP->borderRouterList) {
+            if (thread_addr_is_child(router_short_addr, curBR->routerID)) {
+                // Router children found
+                thread_border_router_children_network_data_check_and_clean(cur->id, curBR->routerID);
+            }
+        }
+    }
+
+    /* Go throgh all services */
+    ns_list_foreach(thread_network_data_service_cache_entry_t, service, &network_data->service_list) {
+        ns_list_foreach(thread_network_data_service_server_entry_t, server, &service->server_list) {
+            if (thread_addr_is_child(router_short_addr, server->router_id)) {
+                // Router children found
+                thread_border_router_children_network_data_check_and_clean(cur->id, server->router_id);
+            }
+        }
+    }
+}
+
 static bool thread_border_router_local_network_data_service_match(thread_network_local_data_cache_entry_t *local_data, thread_network_data_service_cache_entry_t *service, uint16_t router_id)
 {
     bool instance_found = false;
@@ -372,6 +430,8 @@ static bool thread_border_router_local_srv_data_in_network_data_check(protocol_i
         }
     }
 
+    thread_border_router_lost_children_nwk_data_validate(cur, router_id);
+
     return true;
 }