additional reed advertisement (#1609)

reed advertisement sent when an advertisement
from lower partition is heard.

Author: deepakvenugopal

source/6LoWPAN/Thread/thread_common.h

@@ -286,6 +286,7 @@ typedef struct thread_info_s {
     uint16_t native_commissioner_port;
     uint16_t routerShortAddress;
     uint16_t reedJitterTimer;
+    uint16_t reedMergeAdvTimer;
     uint16_t routerIdReqCoapID;  // COAP msg id of RouterID request
     int16_t childUpdateReqTimer;
     uint16_t childUpdateReqMsgId;

source/6LoWPAN/Thread/thread_constants.h

@@ -174,6 +174,10 @@
 #define MIN_DOWNGRADE_NEIGHBORS 7
 #define THREAD_REED_ADVERTISEMENT_DELAY 5000
 
+// Interval after which REED can send an advertisement to help others merge to higher partition.
+// This is not related to default REED advertisements.
+#define THREAD_REED_MERGE_ADVERTISEMENT_INTERVAL 120
+
 /** Default Threshold for router Selection */
 #define ROUTER_DOWNGRADE_THRESHOLD 23 // Define downGrade Threshold when active router is higher than this
 #define ROUTER_UPGRADE_THRESHOLD 16 // Define upgrade Threshold fort REED when Active Router Count is smaller than this upgrade is possible

source/6LoWPAN/Thread/thread_mle_message_handler.c

@@ -239,22 +239,30 @@ static bool thread_router_leader_data_process(protocol_interface_info_entry_t *c
     return true;
 }
 
+static bool thread_heard_lower_partition(protocol_interface_info_entry_t *cur, thread_leader_data_t heard_partition_leader_data)
+{
+    if (heard_partition_leader_data.weighting < thread_info(cur)->thread_leader_data->weighting) {
+        return true;
+    }
+    if (heard_partition_leader_data.weighting == thread_info(cur)->thread_leader_data->weighting &&
+            heard_partition_leader_data.partitionId < thread_info(cur)->thread_leader_data->partitionId) {
+        return true;
+    }
+    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;
     }
-    if (thread_extension_version_check(thread_info(cur)->version)) {
-        // 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;
-        }
-    } else if (thread_info(cur)->thread_leader_data->partitionId >= heard_partition_leader_data.partitionId){
+    // 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
@@ -385,6 +393,10 @@ static void thread_parse_advertisement(protocol_interface_info_entry_t *cur, mle
             if (thread_reed_partitions_merge(cur, shortAddress, leaderData)) {
                 return;
             }
+            // REED advertisement to lower partition to help merge faster
+            if (thread_heard_lower_partition(cur,leaderData)) {
+                thread_router_bootstrap_reed_merge_advertisement(cur);
+            }
         } else {
             //Router
             if (!thread_router_leader_data_process(cur, mle_msg->packet_src_address, &leaderData, &routeTlv, entry_temp) ) {

source/6LoWPAN/Thread/thread_router_bootstrap.c

@@ -2368,6 +2368,16 @@ void thread_router_bootstrap_reed_advertisements_start(protocol_interface_info_e
     cur->thread_info->routerSelectParameters.reedAdvertisementTimeout = eventOS_timeout_ms(thread_reed_advertisements_cb,timeout, cur);
 }
 
+void thread_router_bootstrap_reed_merge_advertisement(protocol_interface_info_entry_t *cur)
+{
+    if (cur->thread_info->reedMergeAdvTimer > 1) {
+        return;
+    }
+    thread_reed_advertise(cur);
+    // 120s second timer reinitialised before next merge advertisement
+    cur->thread_info->reedMergeAdvTimer = THREAD_REED_MERGE_ADVERTISEMENT_INTERVAL;
+
+}
 void thread_router_bootstrap_router_id_release(protocol_interface_info_entry_t *cur)
 {
     tr_debug("Router ID Release");
@@ -2417,6 +2427,12 @@ void thread_router_bootstrap_timer(protocol_interface_info_entry_t *cur, uint32_
         }
     }
 
+    if (cur->thread_info->reedMergeAdvTimer > ticks) {
+        cur->thread_info->reedMergeAdvTimer -= ticks;
+    } else {
+        cur->thread_info->reedMergeAdvTimer = 0;
+    }
+
     if (!thread_info->leader_private_data && thread_info->thread_attached_state == THREAD_STATE_CONNECTED_ROUTER) {
         // Non leader router checks
         if (thread_info->routing.activated) {

source/6LoWPAN/Thread/thread_router_bootstrap.h

@@ -45,6 +45,7 @@ struct mle_security_header;
 struct buffer;
 
 void thread_router_bootstrap_reed_advertisements_start(protocol_interface_info_entry_t *cur);
+void thread_router_bootstrap_reed_merge_advertisement(protocol_interface_info_entry_t *cur);
 int thread_router_bootstrap_mle_advertise(struct protocol_interface_info_entry *cur);
 
 void thread_router_bootstrap_child_information_clear(protocol_interface_info_entry_t *cur);
@@ -101,6 +102,7 @@ void thread_router_bootstrap_address_change_notify_send(protocol_interface_info_
 #define thread_router_bootstrap_network_data_distribute(cur)
 #define thread_router_bootstrap_routing_allowed(cur) false
 #define thread_router_bootstrap_address_change_notify_send(cur)
+#define thread_router_bootstrap_reed_merge_advertisement(cur)
 
 #endif/*HAVE_THREAD_ROUTER*/