Fix for Router advertisement process in REED (#1658)

Process router advertisements in REED mode, and merge partitions if needed.

Author: Tero Heinonen

source/6LoWPAN/Thread/thread_bootstrap.c

@@ -325,11 +325,7 @@ int thread_bootstrap_partition_process(protocol_interface_info_entry_t *cur, uin
         tr_debug("Dropping advertisement from old partition without sequence number increase");
         return -2;
     }
-    if (heard_partition_routers == 0 && active_routers == 1) {
-        //heard a REED and I am in a singleton partition so merge
-        tr_debug("Heard a REED and I am a singleton - merge");
-        return 2;
-    }
+
     /*Rule 0: If we are going to form Higher partition than heard we dont try to attach to lower ones
      */
     if (thread_extension_enabled(cur) &&
@@ -343,6 +339,12 @@ int thread_bootstrap_partition_process(protocol_interface_info_entry_t *cur, uin
         }
     }
 
+    if ((heard_partition_routers == 0 && active_routers == 1) && thread_am_router(cur)) {
+        //heard a REED and I am a lonely router in a singleton partition, so merge
+        tr_debug("Heard a REED and I am a singleton - merge");
+        return 2;
+    }
+
     //Rule 1: A non-singleton Thread Network Partition always has higher priority than a singleton Thread Network Partition
     if (heard_partition_routers > 1 && active_routers == 1) {
         tr_debug("Heard a nonsingleton and i am a singleton");

source/6LoWPAN/Thread/thread_mle_message_handler.c

@@ -249,25 +249,6 @@ static bool thread_heard_lower_partition(protocol_interface_info_entry_t *cur, t
     return false;
 }
 
-static bool thread_reed_partitions_merge(protocol_interface_info_entry_t *cur, uint16_t shortAddress, thread_leader_data_t heard_partition_leader_data)
-{
-    if (thread_is_router_addr(shortAddress)) {
-        return false;
-    }
-    // lower weighting heard
-    if (thread_info(cur)->thread_leader_data->weighting > heard_partition_leader_data.weighting) {
-        return false;
-    }
-    // lower/same partition id heard
-    if (thread_info(cur)->thread_leader_data->weighting == heard_partition_leader_data.weighting &&
-            thread_info(cur)->thread_leader_data->partitionId >= heard_partition_leader_data.partitionId ) {
-        return false;
-    }
-    // can merge to a higher weighting/partition id
-    thread_bootstrap_connection_error(cur->id, CON_ERROR_PARTITION_MERGE, NULL);
-    return true;
-}
-
 static bool thread_router_advertiment_tlv_analyze(uint8_t *ptr, uint16_t data_length, thread_leader_data_t *leaderData, uint16_t *shortAddress, mle_tlv_info_t *routeTlv)
 {
     //Read Leader Data and verify connectivity
@@ -401,10 +382,13 @@ static void thread_parse_advertisement(protocol_interface_info_entry_t *cur, mle
                 }
             /* Advertisement from higher / lower partition */
             } else {
-                // process REED advertisement from higher partition
-                if (thread_reed_partitions_merge(cur, shortAddress, leaderData)) {
+                // Check if better partition is heard
+                if (thread_bootstrap_partition_process(cur, thread_get_router_count_from_route_tlv(&routeTlv), &leaderData, &routeTlv) > 0) {
+                    tr_debug("Start Merge");
+                    thread_bootstrap_connection_error(cur->id, CON_ERROR_PARTITION_MERGE, NULL);
                     return;
                 }
+
                 // REED advertisement to lower partition to help merge faster
                 if (thread_heard_lower_partition(cur,leaderData)) {
                     thread_router_bootstrap_reed_merge_advertisement(cur);