Include timestamp tlv in Child ID Response only when it is necessary (#794)

src/core/thread/mle.cpp

@@ -936,12 +936,15 @@ exit:
 
 ThreadError Mle::AppendActiveTimestamp(Message &aMessage)
 {
+    ThreadError error;
     ActiveTimestampTlv timestampTlv;
     const MeshCoP::Timestamp *timestamp(mNetif.GetActiveDataset().GetNetwork().GetTimestamp());
 
+    VerifyOrExit(timestamp || mDeviceState == kDeviceStateLeader, error = kThreadError_None);
+
     timestampTlv.Init();
 
-    // set active timestamp to 0 if there is no valid active operational dataset
+    // only for Leader: set active timestamp to 0 if it is not initialized
     if (timestamp == NULL)
     {
         timestampTlv.SetSeconds(0);
@@ -952,7 +955,10 @@ ThreadError Mle::AppendActiveTimestamp(Message &aMessage)
         *static_cast<MeshCoP::Timestamp *>(&timestampTlv) = *timestamp;
     }
 
-    return aMessage.Append(&timestampTlv, sizeof(timestampTlv));
+    error = aMessage.Append(&timestampTlv, sizeof(timestampTlv));
+
+exit:
+    return error;
 }
 
 ThreadError Mle::AppendPendingTimestamp(Message &aMessage)
@@ -1807,13 +1813,11 @@ ThreadError Mle::HandleDataResponse(const Message &aMessage, const Ip6::MessageI
     VerifyOrExit(networkData.IsValid(), error = kThreadError_Parse);
 
     // Active Timestamp
-    SuccessOrExit(error = Tlv::GetTlv(aMessage, Tlv::kActiveTimestamp, sizeof(activeTimestamp), activeTimestamp));
-    VerifyOrExit(activeTimestamp.IsValid(), error = kThreadError_Parse);
-
-    if (activeTimestamp.GetSeconds() != 0)
+    if (Tlv::GetTlv(aMessage, Tlv::kActiveTimestamp, sizeof(activeTimestamp), activeTimestamp) == kThreadError_None)
     {
         const MeshCoP::Timestamp *timestamp;
 
+        VerifyOrExit(activeTimestamp.IsValid(), error = kThreadError_Parse);
         timestamp = mNetif.GetActiveDataset().GetNetwork().GetTimestamp();
 
         // if received timestamp does not match the local value and message does not contain the dataset,
@@ -2112,18 +2116,11 @@ ThreadError Mle::HandleChildIdResponse(const Message &aMessage, const Ip6::Messa
     {
         VerifyOrExit(activeTimestamp.IsValid(), error = kThreadError_Parse);
 
-        if (activeTimestamp.GetSeconds() != 0)
+        // Active Dataset
+        if (Tlv::GetOffset(aMessage, Tlv::kActiveDataset, offset) == kThreadError_None)
         {
-            // Active Dataset
-            if (Tlv::GetOffset(aMessage, Tlv::kActiveDataset, offset) == kThreadError_None)
-            {
-                aMessage.Read(offset, sizeof(tlv), &tlv);
-                mNetif.GetActiveDataset().Set(activeTimestamp, aMessage, offset + sizeof(tlv), tlv.GetLength());
-            }
-        }
-        else
-        {
-            mNetif.GetActiveDataset().Clear();
+            aMessage.Read(offset, sizeof(tlv), &tlv);
+            mNetif.GetActiveDataset().Set(activeTimestamp, aMessage, offset + sizeof(tlv), tlv.GetLength());
         }
     }
 
@@ -2139,10 +2136,6 @@ ThreadError Mle::HandleChildIdResponse(const Message &aMessage, const Ip6::Messa
             mNetif.GetPendingDataset().Set(pendingTimestamp, aMessage, offset + sizeof(tlv), tlv.GetLength());
         }
     }
-    else
-    {
-        mNetif.GetPendingDataset().Clear();
-    }
 
     // Parent Attach Success
     mParentRequestTimer.Stop();

src/core/thread/mle_router.cpp

@@ -2093,6 +2093,7 @@ ThreadError MleRouter::HandleChildIdRequest(const Message &aMessage, const Ip6::
         mNetif.GetActiveDataset().GetNetwork().GetTimestamp()->Compare(activeTimestamp) != 0)
     {
         child->mRequestTlvs[numTlvs++] = Tlv::kActiveDataset;
+        child->mRequestTlvs[numTlvs++] = Tlv::kActiveTimestamp;
     }
 
     if (pendingTimestamp.GetLength() == 0 ||
@@ -2100,6 +2101,7 @@ ThreadError MleRouter::HandleChildIdRequest(const Message &aMessage, const Ip6::
         mNetif.GetPendingDataset().GetNetwork().GetTimestamp()->Compare(pendingTimestamp) != 0)
     {
         child->mRequestTlvs[numTlvs++] = Tlv::kPendingDataset;
+        child->mRequestTlvs[numTlvs++] = Tlv::kPendingTimestamp;
     }
 
     switch (GetDeviceState())
@@ -2307,8 +2309,6 @@ ThreadError MleRouter::SendChildIdResponse(Child *aChild)
     SuccessOrExit(error = AppendHeader(*message, Header::kCommandChildIdResponse));
     SuccessOrExit(error = AppendSourceAddress(*message));
     SuccessOrExit(error = AppendLeaderData(*message));
-    SuccessOrExit(error = AppendActiveTimestamp(*message));
-    SuccessOrExit(error = AppendPendingTimestamp(*message));
 
     // pick next Child ID that is not being used
     do
@@ -2346,6 +2346,14 @@ ThreadError MleRouter::SendChildIdResponse(Child *aChild)
         case Tlv::kPendingDataset:
             SuccessOrExit(error = AppendPendingDataset(*message));
             break;
+
+        case Tlv::kActiveTimestamp:
+            SuccessOrExit(error = AppendActiveTimestamp(*message));
+            break;
+
+        case Tlv::kPendingTimestamp:
+            SuccessOrExit(error = AppendPendingTimestamp(*message));
+            break;
         }
     }
 

src/core/thread/topology.hpp

@@ -105,7 +105,7 @@ public:
     Ip6::Address mIp6Address[kMaxIp6AddressPerChild];  ///< Registered IPv6 addresses
     uint32_t     mTimeout;                             ///< Child timeout
     uint16_t     mFragmentOffset;                      ///< 6LoWPAN fragment offset
-    uint8_t      mRequestTlvs[5];                      ///< Requested MLE TLVs
+    uint8_t      mRequestTlvs[7];                      ///< Requested MLE TLVs
     uint8_t      mNetworkDataVersion;                  ///< Current Network Data version
     uint16_t     mQueuedIndirectMessageCnt;            ///< Count of queued messages
     bool         mAddSrcMatchEntryShort;               ///< Indicates whether or not to force add short address