net.tomp2p.connection
Class NATUtils

java.lang.Object
  net.tomp2p.connection.NATUtils

public class NATUtils
extends Object

This class is used to do automatic port forwarding. It maps with PMP und UPNP and also unmaps them. It creates a shutdown hook in case the user exits the application without a proper shutdown.

Author:

Thomas Bocek

Constructor Summary

NATUtils()
Constructor.

Method Summary

boolean	mapPMP(int internalPortUDP, int internalPortTCP, int externalPortUDP, int externalPortTCP) Maps with the PMP protocol (http://en.wikipedia.org/wiki/NAT_Port_Mapping_Protocol).
boolean	mapUPNP(String internalHost, int internalPortUDP, int internalPortTCP, int externalPortUDP, int externalPortTCP) Maps with UPNP protocol (http://en.wikipedia.org/wiki/Internet_Gateway_Device_Protocol).
void	shutdown() Since shutdown is also called from the shutdown hook, it might get called twice.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NATUtils

public NATUtils()

Constructor.

Method Detail

mapPMP

public boolean mapPMP(int internalPortUDP,
                      int internalPortTCP,
                      int externalPortUDP,
                      int externalPortTCP)
               throws NatPmpException

Maps with the PMP protocol (http://en.wikipedia.org/wiki/NAT_Port_Mapping_Protocol). One of the drawbacks of this protocol is that it needs to know the IP of the router. To get the IP of the router in Java, we need to use netstat and parse the output.

Parameters:

internalPortUDP - The UDP internal port

internalPortTCP - The TCP internal port

externalPortUDP - The UDP external port

externalPortTCP - The TCP external port

Returns:

True, if the mapping was successful (i.e. the router supports PMP)

Throws:

NatPmpException - the router does not supports PMP

mapUPNP

public boolean mapUPNP(String internalHost,
                       int internalPortUDP,
                       int internalPortTCP,
                       int externalPortUDP,
                       int externalPortTCP)
                throws IOException

Maps with UPNP protocol (http://en.wikipedia.org/wiki/Internet_Gateway_Device_Protocol). Since this uses broadcasting to discover routers, no calling the external program netstat is necessary.

Parameters:

internalHost - The internal host to map the ports to

internalPortUDP - The UDP internal port

internalPortTCP - The TCP internal port

externalPortUDP - The UDP external port

externalPortTCP - The TCP external port

Returns:

True, if at least one mapping was successful (i.e. the router supports UPNP)

Throws:

IOException - Exception

shutdown

public void shutdown()

Since shutdown is also called from the shutdown hook, it might get called twice. Thus, this method deregister NAT mappings only once. If it already has been called, this method does nothing.