MLE: Fix restore of rx-on children. (#1853)

src/core/thread/mle.cpp

@@ -2204,7 +2204,7 @@ void Mle::HandleUdpReceive(Message &aMessage, const Ip6::MessageInfo &aMessageIn
     case Header::kCommandChildUpdateRequest:
         if (mRole == OT_DEVICE_ROLE_LEADER || mRole == OT_DEVICE_ROLE_ROUTER)
         {
-            mNetif.GetMle().HandleChildUpdateRequest(aMessage, aMessageInfo);
+            mNetif.GetMle().HandleChildUpdateRequest(aMessage, aMessageInfo, keySequence);
         }
         else
         {

src/core/thread/mle_router.cpp

@@ -2215,7 +2215,8 @@ exit:
     return error;
 }
 
-otError MleRouter::HandleChildUpdateRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo)
+otError MleRouter::HandleChildUpdateRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo,
+                                            uint32_t aKeySequence)
 {
     static const uint8_t kMaxResponseTlvs = 10;
 
@@ -2315,6 +2316,12 @@ otError MleRouter::HandleChildUpdateRequest(const Message &aMessage, const Ip6::
 
     child->SetLastHeard(Timer::GetNow());
 
+    if (child->IsStateRestoring())
+    {
+        SetChildStateToValid(child);
+        child->SetKeySequence(aKeySequence);
+    }
+
     SendChildUpdateResponse(child, aMessageInfo, tlvs, tlvslength, &challenge);
 
 exit:

src/core/thread/mle_router_ftd.hpp

@@ -691,7 +691,8 @@ private:
     otError HandleParentRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
     otError HandleChildIdRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo,
                                  uint32_t aKeySequence);
-    otError HandleChildUpdateRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
+    otError HandleChildUpdateRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo,
+                                     uint32_t aKeySequence);
     otError HandleChildUpdateResponse(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo,
                                       uint32_t aKeySequence);
     otError HandleDataRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);

src/core/thread/mle_router_mtd.hpp

@@ -139,7 +139,7 @@ private:
     otError HandleAdvertisement(const Message &, const Ip6::MessageInfo &) { return OT_ERROR_DROP; }
     otError HandleParentRequest(const Message &, const Ip6::MessageInfo &) { return OT_ERROR_DROP; }
     otError HandleChildIdRequest(const Message &, const Ip6::MessageInfo &, uint32_t) { return OT_ERROR_DROP; }
-    otError HandleChildUpdateRequest(const Message &, const Ip6::MessageInfo &) { return OT_ERROR_DROP; }
+    otError HandleChildUpdateRequest(const Message &, const Ip6::MessageInfo &, uint32_t) { return OT_ERROR_DROP; }
     otError HandleChildUpdateResponse(const Message &, const Ip6::MessageInfo &, uint32_t) { return OT_ERROR_DROP; }
     otError HandleDataRequest(const Message &, const Ip6::MessageInfo &) { return OT_ERROR_DROP; }
     otError HandleNetworkDataUpdateRouter(void) { return OT_ERROR_NONE; }

src/core/thread/topology.hpp

@@ -83,6 +83,14 @@ public:
      */
     void SetState(State aState) { mState = static_cast<uint8_t>(aState); }
 
+    /**
+     * Check if the neighbor/child is being restored.
+     *
+     * @returns TRUE if the neighbor is being restored, FALSE otherwise.
+     *
+     */
+    bool IsStateRestoring(void) const { return (mState == kStateRestored) || (mState == kStateChildUpdateRequest); }
+
     /**
      * Check if the neighbor/child is in valid state or if it is being restored.
      * When in these states messages can be sent to and/or received from the neighbor/child.
@@ -90,7 +98,7 @@ public:
      * @returns TRUE if the neighbor is in valid, restored, or being restored states, FALSE otherwise.
      *
      */
-    bool IsStateValidOrRestoring(void) const { return (mState == kStateValid) || (mState == kStateRestored); }
+    bool IsStateValidOrRestoring(void) const { return (mState == kStateValid) || IsStateRestoring(); }
 
     /**
      * This method gets the device mode flags.