diff --git a/include/ccnx-tunnel.h b/include/ccnx-tunnel.h
index 0525458..b71d3c1 100644
--- a/include/ccnx-tunnel.h
+++ b/include/ccnx-tunnel.h
@@ -40,7 +40,7 @@
   publishContentObject(const Name &name, const Bytes &contentObject, int freshness);
 
   virtual int
-  sendInterest (const Name &interest, Closure *closure, const Selectors &selectors = Selectors());
+  sendInterest (const Name &interest, const Closure *closure, const Selectors &selectors = Selectors());
 
 
   // prefix is topology-independent
@@ -95,6 +95,9 @@
   virtual TimeoutCallbackReturnValue
   runTimeoutCallback(const Name &interest) _OVERRIDE;
 
+  virtual Closure *
+  dup() const _OVERRIDE;
+
 private:
   CcnxTunnel *m_tunnel;
   Name m_originalInterest;