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 Detail

      • TUNNEL

        public TUNNEL()
    • Method Detail

      • toString

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

        public java.lang.String getRouterHost()
      • setRouterHost

        public void setRouterHost​(java.lang.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 java.lang.String getName()
        Specified by:
        getName in class Protocol
      • init

        public void init()
                  throws java.lang.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:
        java.lang.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 java.lang.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:
        java.lang.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​(java.util.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 java.lang.Object handleDownEvent​(Event evt)
        Overrides:
        handleDownEvent in class TP
      • sendToAllMembers

        public void sendToAllMembers​(byte[] data,
                                     int offset,
                                     int length)
                              throws java.lang.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
        Throws:
        java.lang.Exception
      • sendToSingleMember

        public void sendToSingleMember​(Address dest,
                                       byte[] data,
                                       int offset,
                                       int length)
                                throws java.lang.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
        Throws:
        java.lang.Exception
      • getInfo

        public java.lang.String getInfo()
        Specified by:
        getInfo in class TP