Only send Child Update Request message when no more state changes are pending. (#476)

src/core/net/netif.cpp

@@ -453,6 +453,11 @@ exit:
     return rval;
 }
 
+bool Netif::IsStateChangedCallbackPending(void)
+{
+    return mStateChangedFlags != 0;
+}
+
 void Netif::SetStateChangedFlags(uint32_t aFlags)
 {
     mStateChangedFlags |= aFlags;

src/core/net/netif.hpp

@@ -317,6 +317,14 @@ public:
      */
     ThreadError RegisterCallback(NetifCallback &aCallback);
 
+    /**
+     * This method indicates whether or not a state changed callback is pending.
+     *
+     * @retval TRUE if a state changed callback is pending, FALSE otherwise.
+     *
+     */
+    bool IsStateChangedCallbackPending(void);
+
     /**
      * This method schedules notification of @p aFlags.
      *

src/core/thread/mle.cpp

@@ -61,7 +61,8 @@ Mle::Mle(ThreadNetif &aThreadNetif) :
     mMesh(aThreadNetif.GetMeshForwarder()),
     mMleRouter(aThreadNetif.GetMle()),
     mNetworkData(aThreadNetif.GetNetworkDataLeader()),
-    mParentRequestTimer(&HandleParentRequestTimer, this)
+    mParentRequestTimer(&HandleParentRequestTimer, this),
+    mSendChildUpdateRequest(&HandleSendChildUpdateRequest, this)
 {
     mDeviceState = kDeviceStateDisabled;
     mDeviceMode = ModeTlv::kModeRxOnWhenIdle | ModeTlv::kModeSecureDataRequest | ModeTlv::kModeFFD |
@@ -930,8 +931,6 @@ void Mle::HandleNetifStateChanged(uint32_t aFlags, void *aContext)
 
 void Mle::HandleNetifStateChanged(uint32_t aFlags)
 {
-    bool sendChildUpdateRequest = false;
-
     if ((aFlags & (OT_IP6_ADDRESS_ADDED | OT_IP6_ADDRESS_REMOVED)) != 0)
     {
         if (!mNetif.IsUnicastAddress(mMeshLocal64.GetAddress()))
@@ -948,7 +947,7 @@ void Mle::HandleNetifStateChanged(uint32_t aFlags)
 
         if (mDeviceState == kDeviceStateChild && (mDeviceMode & ModeTlv::kModeFFD) == 0)
         {
-            sendChildUpdateRequest = true;
+            mSendChildUpdateRequest.Post();
         }
     }
 
@@ -960,14 +959,9 @@ void Mle::HandleNetifStateChanged(uint32_t aFlags)
         }
         else
         {
-            sendChildUpdateRequest = true;
+            mSendChildUpdateRequest.Post();
         }
     }
-
-    if (sendChildUpdateRequest)
-    {
-        SendChildUpdateRequest();
-    }
 }
 
 void Mle::HandleParentRequestTimer(void *aContext)
@@ -1217,6 +1211,25 @@ exit:
     return error;
 }
 
+void Mle::HandleSendChildUpdateRequest(void *aContext)
+{
+    static_cast<Mle *>(aContext)->SendChildUpdateRequest();
+}
+
+void Mle::HandleSendChildUpdateRequest(void)
+{
+    // a Network Data udpate can cause a change to the IPv6 address configuration
+    // only send a Child Update Request after we know there are no more pending changes
+    if (mNetif.IsStateChangedCallbackPending())
+    {
+        mSendChildUpdateRequest.Post();
+    }
+    else
+    {
+        SendChildUpdateRequest();
+    }
+}
+
 ThreadError Mle::SendChildUpdateRequest(void)
 {
     ThreadError error = kThreadError_None;

src/core/thread/mle.hpp

@@ -1082,6 +1082,8 @@ private:
     void HandleParentRequestTimer(void);
     static void HandleUdpReceive(void *aContext, otMessage aMessage, const otMessageInfo *aMessageInfo);
     void HandleUdpReceive(Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
+    static void HandleSendChildUpdateRequest(void *aContext);
+    void HandleSendChildUpdateRequest(void);
 
     ThreadError HandleAdvertisement(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
     ThreadError HandleChildIdResponse(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
@@ -1121,6 +1123,8 @@ private:
     Ip6::UdpSocket mSocket;
     uint32_t mTimeout;
 
+    Tasklet mSendChildUpdateRequest;
+
     DiscoverHandler mDiscoverHandler;
     void *mDiscoverContext;
     bool mIsDiscoverInProgress;