Limit MPL forwarding to Thread Routers. (#996)

src/core/net/ip6.cpp

@@ -68,6 +68,11 @@ Message *Ip6::NewMessage(uint16_t reserved)
     return mMessagePool.New(Message::kTypeIp6, sizeof(Header) + sizeof(HopByHopHeader) + sizeof(OptionMpl) + reserved);
 }
 
+bool Ip6::IsForwardingEnabled(void)
+{
+    return mForwardingEnabled;
+}
+
 void Ip6::SetForwardingEnabled(bool aEnable)
 {
     mForwardingEnabled = aEnable;

src/core/net/ip6.hpp

@@ -243,6 +243,14 @@ public:
      */
     void SetReceiveIp6FilterEnabled(bool aEnabled);
 
+    /**
+     * This method indicates whether or not IPv6 forwarding is enabled.
+     *
+     * @returns TRUE if IPv6 forwarding is enabled, FALSE otherwise.
+     *
+     */
+    bool IsForwardingEnabled(void);
+
     /**
      * This method enables/disables IPv6 forwarding.
      *

src/core/net/ip6_mpl.cpp

@@ -166,6 +166,7 @@ void Mpl::AddBufferedMessage(Message &aMessage, uint16_t aSeedId, uint8_t aSeque
     uint32_t nextTransmissionTime;
     uint8_t hopLimit;
 
+    VerifyOrExit(GetTimerExpirations() > 0,);
     VerifyOrExit((messageCopy = aMessage.Clone()) != NULL, error = kThreadError_NoBufs);
 
     if (!aIsOutbound)