--- a/src/internet-node/udp-socket-impl.cc	Wed Jun 04 09:18:44 2008 -0700
+++ b/src/internet-node/udp-socket-impl.cc	Wed Jun 04 09:19:16 2008 -0700
@@ -217,6 +217,13 @@
 }
 
 int 
+UdpSocketImpl::Listen (uint32_t queueLimit)
+{
+  m_errno = Socket::ERROR_OPNOTSUPP;
+  return -1;
+}
+
+int 
 UdpSocketImpl::Send (Ptr<Packet> p)
 {
   NS_LOG_FUNCTION (this << p);

--- a/src/internet-node/udp-socket-impl.h	Wed Jun 04 09:18:44 2008 -0700
+++ b/src/internet-node/udp-socket-impl.h	Wed Jun 04 09:19:16 2008 -0700
@@ -57,6 +57,7 @@
   virtual int ShutdownSend (void);
   virtual int ShutdownRecv (void);
   virtual int Connect(const Address &address);
+  virtual int Listen (uint32_t queueLimit);
   virtual int Send (Ptr<Packet> p);
   virtual int SendTo (Ptr<Packet> p, const Address &address);
   virtual uint32_t GetTxAvailable (void) const;

--- a/src/node/packet-socket.cc	Wed Jun 04 09:18:44 2008 -0700
+++ b/src/node/packet-socket.cc	Wed Jun 04 09:19:16 2008 -0700
@@ -220,6 +220,12 @@
   NotifyConnectionFailed ();
   return -1;
 }
+int 
+PacketSocket::Listen(uint32_t queueLimit)
+{
+  m_errno = Socket::ERROR_OPNOTSUPP;
+  return -1;
+}
 
 int
 PacketSocket::Send (Ptr<Packet> p)

--- a/src/node/packet-socket.h	Wed Jun 04 09:18:44 2008 -0700
+++ b/src/node/packet-socket.h	Wed Jun 04 09:19:16 2008 -0700
@@ -71,6 +71,8 @@
  *       The fields "physical address", device, and protocol are filled.
  *
  * - Accept: not allowed
+ *
+ * - Listen: returns -1 (OPNOTSUPP)
  */
 class PacketSocket : public Socket
 {
@@ -90,6 +92,7 @@
   virtual int ShutdownSend (void);
   virtual int ShutdownRecv (void);
   virtual int Connect(const Address &address);
+  virtual int Listen(uint32_t queueLimit);
   virtual int Send (Ptr<Packet> p);
   virtual uint32_t GetTxAvailable (void) const;
 

--- a/src/node/socket.cc	Wed Jun 04 09:18:44 2008 -0700
+++ b/src/node/socket.cc	Wed Jun 04 09:19:16 2008 -0700
@@ -103,12 +103,6 @@
   m_receivedData = receivedData;
 }
 
-int Socket::Listen (uint32_t queueLimit)
-{
-  return 0; //XXX the base class version does nothing
-}
-
-
 int Socket::Send (const uint8_t* buf, uint32_t size)
 {
   NS_LOG_FUNCTION_NOARGS ();

--- a/src/node/socket.h	Wed Jun 04 09:18:44 2008 -0700
+++ b/src/node/socket.h	Wed Jun 04 09:19:16 2008 -0700
@@ -231,9 +231,9 @@
   /**
    * \brief Listen for incoming connections.
    * \param queueLimit maximum number of incoming request to queue
-   * \returns XXX an error code
+   * \returns 0 on success, -1 on error (in which case errno is set).
    */
-  virtual int Listen (uint32_t queueLimit);
+  virtual int Listen (uint32_t queueLimit) = 0;
 
   /**
    * \brief Send data (or dummy data) to the remote host