Clean up indirect messages when a child is removed. (#941)

src/core/thread/mesh_forwarder.cpp

@@ -181,6 +181,46 @@ void MeshForwarder::ScheduleTransmissionTask(void *aContext)
     static_cast<MeshForwarder *>(aContext)->ScheduleTransmissionTask();
 }
 
+void MeshForwarder::UpdateIndirectMessages(void)
+{
+    Child *children;
+    uint8_t numChildren;
+
+    VerifyOrExit(mSendBusy == false,);
+
+    children = mMle.GetChildren(&numChildren);
+
+    for (uint8_t i = 0; i < numChildren; i++)
+    {
+        Child *child = &children[i];
+        Message *nextMessage;
+
+        if (child->mState == Child::kStateValid || child->mQueuedIndirectMessageCnt == 0)
+        {
+            continue;
+        }
+
+        for (Message *message = mSendQueue.GetHead(); message; message = nextMessage)
+        {
+            nextMessage = message->GetNext();
+
+            message->ClearChildMask(i);
+
+            if (!message->IsChildPending())
+            {
+                mSendQueue.Dequeue(*message);
+                message->Free();
+            }
+        }
+
+        child->mQueuedIndirectMessageCnt = 0;
+        ClearSrcMatchEntry(*child);
+    }
+
+exit:
+    return;
+}
+
 void MeshForwarder::ScheduleTransmissionTask()
 {
     ThreadError error = kThreadError_None;
@@ -189,6 +229,8 @@ void MeshForwarder::ScheduleTransmissionTask()
 
     VerifyOrExit(mSendBusy == false, error = kThreadError_Busy);
 
+    UpdateIndirectMessages();
+
     children = mMle.GetChildren(&numChildren);
 
     for (int i = 0; i < numChildren; i++)

src/core/thread/mesh_forwarder.hpp

@@ -171,6 +171,12 @@ public:
      */
     void SetDiscoverParameters(uint32_t aScanChannels, uint16_t aScanDuration);
 
+    /**
+     * This method frees any indirect messages queued for children that are no longer attached.
+     *
+     */
+    void UpdateIndirectMessages(void);
+
     /**
      * This method returns a reference to the send queue.
      *

src/core/thread/mle_constants.hpp

@@ -62,6 +62,7 @@ enum
     kParentResponseMaxDelayRouters = 500,   ///< Maximum delay for response for Parent Request sent to routers only
     kParentResponseMaxDelayAll     = 1000,  ///< Maximum delay for response for Parent Request sent to all devices
     kMaxResponseDelay              = 1000,  ///< Maximum delay before responding to a multicast request
+    kMaxChildIdRequestTimeout      = 5000,  ///< Maximum delay for receiving a Child ID Request
 };
 
 enum

src/core/thread/mle_router.cpp

@@ -1701,12 +1701,28 @@ void MleRouter::HandleStateUpdateTimer(void)
     // update children state
     for (int i = 0; i < mMaxChildrenAllowed; i++)
     {
-        if (mChildren[i].mState == Neighbor::kStateInvalid)
+        uint32_t timeout = 0;
+
+        switch (mChildren[i].mState)
         {
+        case Neighbor::kStateInvalid:
+        case Neighbor::kStateChildIdRequest:
             continue;
+
+        case Neighbor::kStateParentRequest:
+            timeout = kMaxChildIdRequestTimeout;
+            break;
+
+        case Neighbor::kStateValid:
+            timeout = Timer::SecToMsec(mChildren[i].mTimeout);
+            break;
+
+        case Neighbor::kStateLinkRequest:
+            assert(false);
+            break;
         }
 
-        if ((Timer::GetNow() - mChildren[i].mLastHeard) >= Timer::SecToMsec(mChildren[i].mTimeout))
+        if ((Timer::GetNow() - mChildren[i].mLastHeard) >= timeout)
         {
             RemoveNeighbor(mChildren[i]);
         }
@@ -2565,6 +2581,7 @@ ThreadError MleRouter::RemoveNeighbor(Neighbor &aNeighbor)
     case kDeviceStateLeader:
         if (aNeighbor.mState == Neighbor::kStateValid && !IsActiveRouter(aNeighbor.mValid.mRloc16))
         {
+            mMesh.UpdateIndirectMessages();
             mNetif.SetStateChangedFlags(OT_THREAD_CHILD_REMOVED);
             mNetworkData.SendServerDataNotification(aNeighbor.mValid.mRloc16);
         }