protocol
Class DatagramChannel

java.lang.Object
  protocol.DatagramChannel

All Implemented Interfaces:

java.lang.Runnable

public class DatagramChannel
extends java.lang.Object
implements java.lang.Runnable

Binds the UDP port. Each peer is associated with one DatagramChannel object.

Author:

Mikica B Kocic

Field Summary

private static int	INBOUND_UDP_BUFFER_SIZE The default size for the inbound UDP buffer
private int	localPort The local UDP port where datagram socket is bound
private java.lang.Thread	pduReceiverThread The UDP receiver worker thread
private RemotePeer	remotePeer Current remote peer receiving datagrams from UDP socket
private boolean	running Indicates that worker thread should be running (receiving datagrams)
private java.net.DatagramSocket	udpReceiver The UDP receiver socket
private SymmetricCipher	usedPduCipher Currently used symmetric cipher

Constructor Summary

DatagramChannel(int localPort)
Constructor for the DatagramChannel object

Method Summary

void	addNewPeer(RemotePeer remotePeer) Adds new peer to receive incoming PDUs
int	getLocalPort() Returns used local UDP port.
RemotePeer	getRemotePeer() Returns the remote peer
SymmetricCipher	getUsedSymmetricCipher() Gets current cipher used for PDU ciphering
boolean	hasRemotePeer() Returns if there is active remote peer
boolean	isPearDead(int maxIdleTimeMillis) Returns if peer seems to be dead (we are not receiving PDUs from it).
protected void	packetDump(byte[] octets, int len, java.net.InetAddress addr, int port, boolean incoming) Dumps information of a frame (in bytes) to standard error.
void	removePeer() Detaches peer and all its call from the UDP receiver
void	run() Receives (and deciphers) PDUs from remote peers in a loop.
void	send(OctetBuffer pdu, java.net.InetAddress peerAddr, int peerPort) Encrypts and sends PDUs to remote peer
void	stop() Stops PDU receiver thread
void	useSymmetricCipher(SymmetricCipher cipherEngine) Sets cipher to be used for PDU ciphering

Methods inherited from class java.lang.Object

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

Field Detail

INBOUND_UDP_BUFFER_SIZE

private static final int INBOUND_UDP_BUFFER_SIZE

The default size for the inbound UDP buffer

See Also:

Constant Field Values

localPort

private int localPort

The local UDP port where datagram socket is bound

udpReceiver

private java.net.DatagramSocket udpReceiver

The UDP receiver socket

pduReceiverThread

private java.lang.Thread pduReceiverThread

The UDP receiver worker thread

running

private volatile boolean running

Indicates that worker thread should be running (receiving datagrams)

remotePeer

private RemotePeer remotePeer

Current remote peer receiving datagrams from UDP socket

usedPduCipher

private SymmetricCipher usedPduCipher

Currently used symmetric cipher

Constructor Detail

DatagramChannel

public DatagramChannel(int localPort)

Constructor for the DatagramChannel object

Parameters:

localPort - local UDP port receiving peer's PDUs

Throws:

java.net.SocketException - Thrown if the UDP socket cannot be created

java.net.UnknownHostException - Thrown if the remoteHost cannot be resolved

Method Detail

getLocalPort

public int getLocalPort()

Returns used local UDP port.

useSymmetricCipher

public void useSymmetricCipher(SymmetricCipher cipherEngine)

Sets cipher to be used for PDU ciphering

getUsedSymmetricCipher

public SymmetricCipher getUsedSymmetricCipher()

Gets current cipher used for PDU ciphering

addNewPeer

public void addNewPeer(RemotePeer remotePeer)

Adds new peer to receive incoming PDUs

hasRemotePeer

public boolean hasRemotePeer()

Returns if there is active remote peer

getRemotePeer

public RemotePeer getRemotePeer()

Returns the remote peer

isPearDead

public boolean isPearDead(int maxIdleTimeMillis)

Returns if peer seems to be dead (we are not receiving PDUs from it).

removePeer

public void removePeer()

Detaches peer and all its call from the UDP receiver

stop

public void stop()

Stops PDU receiver thread

run

public void run()

Receives (and deciphers) PDUs from remote peers in a loop. Dispatches inbound PDUs to associated instance of the RemotePeer that will handle PDUs.

Specified by:

run in interface java.lang.Runnable

send

public void send(OctetBuffer pdu,
                 java.net.InetAddress peerAddr,
                 int peerPort)

Encrypts and sends PDUs to remote peer

packetDump

protected void packetDump(byte[] octets,
                          int len,
                          java.net.InetAddress addr,
                          int port,
                          boolean incoming)

Dumps information of a frame (in bytes) to standard error.

Parameters:

octets - The octets of the in- or outgoing PDU

len - The size of PDU

addr - The remote host address

port - The port number

incoming - Indicates if it is inbound (true) or outgoing (false) PDU