Add MeshCoP State TLV (#377)

* Add MeshCoP State TLV

src/core/thread/meshcop_dataset_manager.cpp

@@ -28,7 +28,7 @@
 
 /**
  * @file
- *   This file implements common methods for manipulating MeshCoP Datasets.
+ *   This file implements MeshCoP Datasets manager to process commands.
  *
  */
 
@@ -236,8 +236,9 @@ void DatasetManager::HandleSet(Coap::Header &aHeader, Message &aMessage, const I
     Timestamp timestamp;
     uint16_t offset = aMessage.GetOffset();
     uint8_t type;
+    StateTlv::State state = StateTlv::kAccept;
 
-    VerifyOrExit(mMle.GetDeviceState() == Mle::kDeviceStateLeader, ;);
+    VerifyOrExit(mMle.GetDeviceState() == Mle::kDeviceStateLeader, state = StateTlv::kReject);
 
     type = strcmp(mUri, OPENTHREAD_URI_ACTIVE_SET) == 0 ? Tlv::kActiveTimestamp : Tlv::kPendingTimestamp;
 
@@ -255,24 +256,30 @@ void DatasetManager::HandleSet(Coap::Header &aHeader, Message &aMessage, const I
     }
 
     // verify the request includes a timestamp that is ahead of the locally stored value
-    VerifyOrExit(offset < aMessage.GetLength() && mLocal.GetTimestamp().Compare(timestamp) > 0, ;);
+    VerifyOrExit(offset < aMessage.GetLength() && mLocal.GetTimestamp().Compare(timestamp) > 0, state = StateTlv::kReject);
 
     mLocal.Set(aMessage, aMessage.GetOffset(), static_cast<uint8_t>(aMessage.GetLength() - aMessage.GetOffset()));
     mNetwork = mLocal;
     mNetworkDataLeader.IncrementVersion();
     mNetworkDataLeader.IncrementStableVersion();
 
-    SendSetResponse(aHeader, aMessageInfo);
-
 exit:
+
+    if (mMle.GetDeviceState() == Mle::kDeviceStateLeader)
+    {
+        SendSetResponse(aHeader, aMessageInfo, state);
+    }
+
     return;
 }
 
-void DatasetManager::SendSetResponse(const Coap::Header &aRequestHeader, const Ip6::MessageInfo &aMessageInfo)
+void DatasetManager::SendSetResponse(const Coap::Header &aRequestHeader, const Ip6::MessageInfo &aMessageInfo,
+                                     StateTlv::State aState)
 {
     ThreadError error = kThreadError_None;
     Coap::Header responseHeader;
     Message *message;
+    StateTlv state;
 
     VerifyOrExit((message = Ip6::Udp::NewMessage(0)) != NULL, error = kThreadError_NoBufs);
     responseHeader.Init();
@@ -285,6 +292,9 @@ void DatasetManager::SendSetResponse(const Coap::Header &aRequestHeader, const I
     responseHeader.Finalize();
     SuccessOrExit(error = message->Append(responseHeader.GetBytes(), responseHeader.GetLength()));
 
+    state.SetState(aState);
+    SuccessOrExit(error = message->Append(&state, sizeof(state)));
+
     SuccessOrExit(error = mCoapServer.SendMessage(*message, aMessageInfo));
 
     otLogInfoMeshCoP("sent dataset response\n");

src/core/thread/meshcop_dataset_manager.hpp

@@ -92,7 +92,7 @@ private:
     void HandleTimer(void);
 
     ThreadError Register(void);
-    void SendSetResponse(const Coap::Header &aRequestHeader, const Ip6::MessageInfo &aMessageInfo);
+    void SendSetResponse(const Coap::Header &aRequestHeader, const Ip6::MessageInfo &aMessageInfo, StateTlv::State aState);
 
     Coap::Resource mResource;
     Timer mTimer;

src/core/thread/meshcop_tlvs.hpp

@@ -69,6 +69,7 @@ public:
         kMeshLocalPrefix   = 7,   ///< Mesh Local Prefix TLV
         kSecurityPolicy    = 12,  ///< Security Policy TLV
         kActiveTimestamp   = 14,  ///< Active Timestamp TLV
+        kState             = 16,  ///< State TLV
         kPendingTimestamp  = 51,  ///< Pending Timestamp TLV
         kDelayTimer        = 52,  ///< Delay Timer TLV
         kChannelMask       = 53,  ///< Channel Mask TLV
@@ -659,6 +660,59 @@ public:
     bool IsValid(void) const { return GetLength() == sizeof(*this) - sizeof(Tlv); }
 } OT_TOOL_PACKED_END;
 
+/**
+ * This class implements State TLV generation and parsing.
+ *
+ */
+OT_TOOL_PACKED_BEGIN
+class StateTlv: public Tlv
+{
+public:
+    /**
+      * State TLV values.
+      */
+    enum State
+    {
+        kReject  = -1,   ///< Reject
+        kPending = 0,    ///< Pending
+        kAccept  = 1,    ///< Accept
+    };
+
+    /**
+     * This method initializes the TLV.
+     *
+     */
+    void Init(void) { SetType(kState); SetLength(sizeof(*this) - sizeof(Tlv)); }
+
+    /**
+     * This method indicates whether or not the TLV appears to be well-formed.
+     *
+     * @retval TRUE   If the TLV appears to be well-formed.
+     * @retval FALSE  If the TLV does not appear to be well-formed.
+     *
+     */
+    bool IsValid(void) const { return GetLength() == sizeof(*this) - sizeof(Tlv); }
+
+    /**
+     * This method returns the State value.
+     *
+     * @returns The State value.
+     *
+     */
+    State GetState(void) const { return static_cast<State>(mState); }
+
+    /**
+     * This method sets the State value.
+     *
+     * @param[in]  aState  The State value.
+     *
+     */
+    void SetState(State aState) { mState = static_cast<uint8_t>(aState); }
+
+private:
+    uint8_t mState;
+} OT_TOOL_PACKED_END;
+
 /**
  * This class implements Pending Timestamp TLV generation and parsing.
  *