add Ipv4 and Udp node capabilities, rework Copy methods to include an extra Node * argument

src/node/internet-node.h

@@ -41,12 +41,16 @@ public:
   virtual NetDeviceList*   GetNetDevices() const;
   virtual L3Demux*         GetL3Demux() const;
   virtual Ipv4L4Demux*     GetIpv4L4Demux() const;
+  virtual Ipv4 *           GetIpv4 (void) const;
+  virtual Udp *            GetUdp (void) const;
 
 private:
   // Capabilities
   NetDeviceList*   m_netDevices;
   L3Demux*         m_l3Demux;
   Ipv4L4Demux*     m_ipv4L4Demux;
+  Ipv4 *           m_ipv4;
+  Udp *            m_udp;
  };
 
 }//namespace ns3