filter out outdated MLE advertisement from old partition (#1155)

src/core/thread/mle.cpp

@@ -461,6 +461,8 @@ ThreadError Mle::BecomeChild(otMleAttachFilter aFilter)
     if (aFilter == kMleAttachAnyPartition)
     {
         mParent.mState = Neighbor::kStateInvalid;
+        mLastPartitionId = mMleRouter.GetPreviousPartitionId();
+        mLastPartitionRouterIdSequence = mMleRouter.GetRouterIdSequence();
     }
 
     mParentRequestTimer.Start(kParentRequestRouterTimeout);

src/core/thread/mle.hpp

@@ -1217,6 +1217,8 @@ protected:
     uint8_t mRouterSelectionJitter;         ///< The variable to save the assigned jitter value.
     uint8_t mRouterSelectionJitterTimeout;  ///< The Timeout prior to request/release Router ID.
 
+    uint8_t mLastPartitionRouterIdSequence;
+    uint32_t mLastPartitionId;
 private:
     enum
     {

src/core/thread/mle_router.cpp

@@ -1285,6 +1285,12 @@ ThreadError MleRouter::HandleAdvertisement(const Message &aMessage, const Ip6::M
                      leaderData.GetWeighting(), partitionId,
                      mLeaderData.GetWeighting(), mLeaderData.GetPartitionId());
 
+        if (partitionId == mLastPartitionId && (mDeviceMode & ModeTlv::kModeFFD))
+        {
+            VerifyOrExit((static_cast<int8_t>(route.GetRouterIdSequence() - mLastPartitionRouterIdSequence) > 0),
+                         error = kThreadError_Drop);
+        }
+
         if (GetDeviceState() == kDeviceStateChild &&
             (memcmp(&mParent.mMacAddr, &macAddr, sizeof(mParent.mMacAddr)) == 0 || !(mDeviceMode & ModeTlv::kModeFFD)))
         {
@@ -3268,6 +3274,11 @@ void MleRouter::SetPreviousPartitionId(uint32_t aPartitionId)
     mPreviousPartitionId = aPartitionId;
 }
 
+uint32_t MleRouter::GetPreviousPartitionId(void) const
+{
+    return mPreviousPartitionId;
+}
+
 void MleRouter::SetRouterId(uint8_t aRouterId)
 {
     mRouterId = aRouterId;

src/core/thread/mle_router_ftd.hpp

@@ -298,6 +298,12 @@ public:
      */
     ThreadError SetPreferredRouterId(uint8_t aRouterId);
 
+    /**
+     * This method gets the Partition Id which the device joined successfully once.
+     *
+     */
+    uint32_t GetPreviousPartitionId(void) const;
+
     /**
      * This method sets the Partition Id which the device joins successfully.
      *

src/core/thread/mle_router_mtd.hpp

@@ -69,6 +69,7 @@ public:
     void SetLeaderPartitionId(uint32_t) { }
 
     ThreadError SetPreferredRouterId(uint8_t) { return kThreadError_NotImplemented; }
+    uint32_t GetPreviousPartitionId(void) const { return 0; }
     void SetPreviousPartitionId(uint32_t) { }
     void SetRouterId(uint8_t) { }