Class TUNNEL


public class TUNNEL extends TP
Replacement for UDP. Instead of sending packets via UDP, a TCP connection is opened to a Router (using the RouterStub client-side stub), the IP address/port of which was given using channel properties router_host and router_port. All outgoing traffic is sent via this TCP socket to the Router which distributes it to all connected TUNNELs in this group. Incoming traffic received from Router will simply be passed up the stack.

A TUNNEL layer can be used to penetrate a firewall, most firewalls allow creating TCP connections to the outside world, however, they do not permit outside hosts to initiate a TCP connection to a host inside the firewall. Therefore, the connection created by the inside host is reused by Router to send traffic from an outside host to a host inside the firewall.

Author:
Bela Ban
  • Constructor Details

    • TUNNEL

      public TUNNEL()
  • Method Details

    • toString

      public String toString()
      Description copied from class: TP
      debug only
      Overrides:
      toString in class TP
    • getRouterHost

      public String getRouterHost()
    • setRouterHost

      public void setRouterHost(String router_host)
    • getRouterPort

      public int getRouterPort()
    • setRouterPort

      public void setRouterPort(int router_port)
    • getReconnectInterval

      public long getReconnectInterval()
    • setReconnectInterval

      public void setReconnectInterval(long reconnect_interval)
    • getName

      public String getName()
      Specified by:
      getName in class Protocol
    • init

      public void init() throws Exception
      Description copied from class: Protocol
      Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.
      Overrides:
      init in class TP
      Throws:
      Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the channel constructor will throw an exception
    • start

      public void start() throws Exception
      Description copied from class: TP
      Creates the unicast and multicast sockets and starts the unicast and multicast receiver threads
      Overrides:
      start in class TP
      Throws:
      Exception - Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, so Channel.connect(String) will throw an exception
    • stop

      public void stop()
      Description copied from class: Protocol
      This method is called on a Channel.disconnect(). Stops work (e.g. by closing multicast socket). Will be called from top to bottom. This means that at the time of the method invocation the neighbor protocol below is still working. This method will replace the STOP, STOP_OK, CLEANUP and CLEANUP_OK events. The ProtocolStack guarantees that when this method is called all messages in the down queue will have been flushed
      Overrides:
      stop in class TP
    • setProperties

      public boolean setProperties(Properties props)
      Setup the Protocol instance acording to the configuration string
      Overrides:
      setProperties in class TP
      Returns:
      true if no other properties are left. false if the properties still have data in them, ie , properties are left over and not handled by the protocol stack
    • handleDownEvent

      public Object handleDownEvent(Event evt)
      Overrides:
      handleDownEvent in class TP
    • sendToAllMembers

      public void sendToAllMembers(byte[] data, int offset, int length) throws Exception
      Description copied from class: TP
      Send to all members in the group. UDP would use an IP multicast message, whereas TCP would send N messages, one for each member
      Specified by:
      sendToAllMembers in class TP
      Parameters:
      data - The data to be sent. This is not a copy, so don't modify it
      offset -
      length -
      Throws:
      Exception
    • sendToSingleMember

      public void sendToSingleMember(Address dest, byte[] data, int offset, int length) throws Exception
      Description copied from class: TP
      Send to all members in the group. UDP would use an IP multicast message, whereas TCP would send N messages, one for each member
      Specified by:
      sendToSingleMember in class TP
      Parameters:
      dest - Must be a non-null unicast address
      data - The data to be sent. This is not a copy, so don't modify it
      offset -
      length -
      Throws:
      Exception
    • getInfo

      public String getInfo()
      Specified by:
      getInfo in class TP
    • postUnmarshalling

      public void postUnmarshalling(Message msg, Address dest, Address src, boolean multicast)
      Specified by:
      postUnmarshalling in class TP
    • postUnmarshallingList

      public void postUnmarshallingList(Message msg, Address dest, boolean multicast)
      Specified by:
      postUnmarshallingList in class TP