Discard late Child ID responses (#1630)

Child ID response can be accepted only from neighbor that was
selected as parent in the latest parent scan. A device needs to
discard child ID responses from old parents that are responding late.

Old rloc can be released from network data when new rloc is received.

Author: Arto Kinnunen

source/6LoWPAN/Thread/thread_host_bootstrap.c

@@ -752,6 +752,7 @@ static void thread_mle_child_request_receive_cb(int8_t interface_id, mle_message
     switch (mle_msg->message_type) {
 
         case MLE_COMMAND_CHILD_ID_RESPONSE: {
+            uint8_t src_mac64[8];
             uint8_t shortAddress[2];
             uint16_t childId;
             mle_tlv_info_t routeTlv, addressRegisteredTlv, networkDataTlv;
@@ -763,12 +764,21 @@ static void thread_mle_child_request_receive_cb(int8_t interface_id, mle_message
 
             tr_info("Received Child ID Response");
 
+            // Validate that response is coming from the scanned parent candidate
+            memcpy(src_mac64, (mle_msg->packet_src_address + 8), 8);
+            src_mac64[0] ^= 2;
+            if (memcmp(src_mac64, scan_result->mac64, 8) != 0) {
+                tr_debug("Drop Child ID response from previous request");
+                return;
+            }
+
             // Clear old data
             if (cur->thread_info->releaseRouterId) {
                 thread_bootstrap_clear_neighbor_entries(cur);
-                cur->thread_info->localServerDataBase.release_old_address = true;
             }
 
+            cur->thread_info->localServerDataBase.release_old_address = true;
+
             thread_clean_all_routers_from_neighbor_list(cur->id);
             thread_leader_service_stop(interface_id);
             thread_leader_service_leader_data_free(cur->thread_info);

source/6LoWPAN/Thread/thread_network_data_storage.h

@@ -184,7 +184,7 @@ typedef struct thread_network_local_data_cache_entry_s {
     thread_network_data_prefix_list_t prefix_list; /*!< Local parsed or generated service list */
     thread_network_data_service_list_t service_list;
     uint16_t registered_rloc16;/*!< Address used for latest registration */
-    bool release_old_address:1;/*!< true if release of old address is needed */
+    bool release_old_address:1;/*!< true if network data  can be released from old address */
     bool publish_active:1;/*!< true when publish is active */
     bool publish_pending:1;/*!< true when publish attempt made during active publish */
 } thread_network_local_data_cache_entry_t;