diff --git a/include/ccnx-closure.h b/include/ccnx-closure.h
new file mode 100644
index 0000000..54306d6
--- /dev/null
+++ b/include/ccnx-closure.h
@@ -0,0 +1,41 @@
+#ifndef CCNX_CLOSURE_H
+#define CCNX_CLOSURE_H
+
+#include "ccnx-common.h"
+
+using namespace std;
+
+namespace Ccnx {
+
+class Closure 
+{
+public:
+  typedef boost::function<void (const string &, const Bytes &)> DataCallback;
+
+  typedef enum
+  {
+    RESULT_OK,
+    RESULT_REEXPRESS
+  } TimeoutCallbackReturnValue;
+
+  typedef boost::function<TimeoutCallbackReturnValue (const string &)> TimeoutCallback;
+
+  Closure(int retry, const DataCallback &dataCallback, const TimeoutCallback &timeoutCallback);
+  Closure(const Closure &other);
+  int getRetry() {return m_retry;}
+  void decRetry() { m_retry--;}
+  virtual ~Closure();
+  virtual void 
+  runDataCallback(const string &name, const Bytes &content);
+  virtual TimeoutCallbackReturnValue 
+  runTimeoutCallback(const string &interest);
+
+protected:
+  int m_retry;
+  TimeoutCallback *m_timeoutCallback;
+  DataCallback *m_dataCallback;  
+};
+
+} // Ccnx
+
+#endif
diff --git a/include/ccnx-common.h b/include/ccnx-common.h
new file mode 100644
index 0000000..7394c03
--- /dev/null
+++ b/include/ccnx-common.h
@@ -0,0 +1,24 @@
+#ifndef CCNX_COMMON_H
+#define CCNX_COMMON_H
+
+#include <vector>
+#include <boost/shared_ptr.hpp>
+#include <boost/exception/all.hpp>
+#include <boost/function.hpp>
+#include <string>
+#include <sstream>
+#include <map>
+#include <utility>
+
+using namespace std;
+namespace Ccnx {
+typedef vector<unsigned char> Bytes;
+
+void
+readRaw(Bytes &bytes, const unsigned char *src, size_t len);
+
+const unsigned char *
+head(const Bytes &bytes);
+
+} // Ccnx
+#endif // CCNX_COMMON_H
diff --git a/include/ccnx-pco.h b/include/ccnx-pco.h
index 5b48ccf..1357333 100644
--- a/include/ccnx-pco.h
+++ b/include/ccnx-pco.h
@@ -1,9 +1,8 @@
 #ifndef CCNX_CONTENT_OBJECT_H
 #define CCNX_CONTENT_OBJECT_H
 
-#include <boost/exception/all.hpp>
-#include <boost/shared_ptr.hpp>
 #include "ccnx-wrapper.h"
+#include "ccnx-common.h"
 
 using namespace std;
 
diff --git a/include/ccnx-tunnel.h b/include/ccnx-tunnel.h
index c17569d..4e1eade 100644
--- a/include/ccnx-tunnel.h
+++ b/include/ccnx-tunnel.h
@@ -1,13 +1,10 @@
 #ifndef CCNX_TUNNEL_H
 #define CCNX_TUNNEL_H
 
-#include <string>
-#include <boost/function.hpp>
 #include <boost/variant.hpp>
 #include <boost/thread/locks.hpp>
-#include <utility>
-#include <map>
 
+#include "ccnx-common.h"
 #include "ccnx-wrapper.h"
 
 #define _OVERRIDE 
@@ -40,10 +37,10 @@
 
   // name is topology-independent
   virtual int
-  publishData(const string &name, const char *buf, size_t len, int freshness) _OVERRIDE;
+  publishData(const string &name, const unsigned char *buf, size_t len, int freshness) _OVERRIDE;
 
   virtual int
-  sendInterest (const std::string &interest, const DataCallback &dataCallback, int retry = 0, const TimeoutCallback &timeoutCallback = TimeoutCallback()) _OVERRIDE;
+  sendInterest (const std::string &interest, Closure *closure);
 
 
   // prefix is topology-independent
@@ -76,7 +73,7 @@
   handleTunneledInterest(const string &tunneldInterest);
   
   void
-  handleTunneledData(const string &name, const Bytes &tunneledData, const DataCallback &originalDataCallback);
+  handleTunneledData(const string &name, const Bytes &tunneledData, const Closure::DataCallback &originalDataCallback);
 
 protected:
   // need a way to update local prefix, perhaps using macports trick, but eventually we need something more portable
@@ -85,15 +82,17 @@
   Lock m_ritLock;
 };
 
-class TunnelClosurePass : public ClosurePass
+class TunnelClosure : public Closure
 {
 public:
-  TunnelClosurePass(int retry, const CcnxWrapper::DataCallback &dataCallback, const CcnxWrapper::TimeoutCallback &timeoutCallback, CcnxTunnel *tunnel, const string &originalInterest);
+  TunnelClosure(int retry, const DataCallback &dataCallback, const TimeoutCallback &timeoutCallback, CcnxTunnel *tunnel, const string &originalInterest);
+
+  TunnelClosure(const Closure *closure, CcnxTunnel *tunnel, const string &originalInterest);
 
   virtual void 
   runDataCallback(const string &name, const Bytes &content) _OVERRIDE;
 
-  virtual CcnxWrapper::TimeoutCallbackReturnValue
+  virtual TimeoutCallbackReturnValue
   runTimeoutCallback(const string &interest) _OVERRIDE;
 
 private:
diff --git a/include/ccnx-wrapper.h b/include/ccnx-wrapper.h
index b4a8536..6ee5749 100644
--- a/include/ccnx-wrapper.h
+++ b/include/ccnx-wrapper.h
@@ -10,38 +10,22 @@
 #include <ccn/signing.h>
 }
 
-#include <vector>
-#include <boost/exception/all.hpp>
 #include <boost/thread/recursive_mutex.hpp>
 #include <boost/thread/thread.hpp>
-#include <boost/function.hpp>
-#include <string>
-#include <sstream>
-#include <map>
+
+#include "ccnx-common.h"
+#include "ccnx-closure.h"
 
 using namespace std;
 
 namespace Ccnx {
 
-typedef vector<unsigned char> Bytes;
-
-void
-readRaw(Bytes &bytes, const unsigned char *src, size_t len);
-
 struct CcnxOperationException : virtual boost::exception, virtual exception { };
 
-class CcnxWrapper {
+class CcnxWrapper 
+{
 public:
-  typedef boost::function<void (const string &, const Bytes &)> DataCallback;
   typedef boost::function<void (const string &)> InterestCallback;
-  typedef enum
-  {
-    RESULT_OK,
-    RESULT_REEXPRESS
-  } TimeoutCallbackReturnValue;
-  typedef boost::function<TimeoutCallbackReturnValue (const string &)> TimeoutCallback;
-
-public:
 
   CcnxWrapper();
   virtual ~CcnxWrapper();
@@ -53,10 +37,10 @@
   clearInterestFilter (const string &prefix);
 
   virtual int 
-  sendInterest (const string &strInterest, const DataCallback &dataCallback, int retry = 0, const TimeoutCallback &timeoutCallback = TimeoutCallback());
+  sendInterest (const string &strInterest, Closure *closure);
 
   virtual int 
-  publishData (const string &name, const char *buf, size_t len, int freshness);
+  publishData (const string &name, const unsigned char *buf, size_t len, int freshness);
 
   int
   publishData (const string &name, const Bytes &content, int freshness);
@@ -69,7 +53,7 @@
 
 protected:
   Bytes
-  createContentObject(const string &name, const char *buf, size_t len, int freshness);
+  createContentObject(const string &name, const unsigned char *buf, size_t len, int freshness);
 
   int 
   putToCcnd (const Bytes &contentObject);
@@ -97,8 +81,6 @@
   void
   ccnLoop ();
 
-  int 
-  sendInterest (const string &strInterest, void *dataPass);
   /// @endcond
 
 protected:
@@ -116,22 +98,6 @@
 
 typedef boost::shared_ptr<CcnxWrapper> CcnxWrapperPtr;
 
-class ClosurePass 
-{
-public:
-  ClosurePass(int retry, const CcnxWrapper::DataCallback &dataCallback, const CcnxWrapper::TimeoutCallback &timeoutCallback);
-  int getRetry() {return m_retry;}
-  void decRetry() { m_retry--;}
-  virtual ~ClosurePass();
-  virtual void runDataCallback(const string &name, const Bytes &content);
-  virtual CcnxWrapper::TimeoutCallbackReturnValue runTimeoutCallback(const string &interest);
-
-protected:
-  int m_retry;
-  CcnxWrapper::TimeoutCallback *m_timeoutCallback;
-  CcnxWrapper::DataCallback *m_dataCallback;  
-};
-
 
 } // Ccnx