jist.swans.trans
Class TcpSocket

java.lang.Object
  jist.swans.trans.TcpSocket

All Implemented Interfaces:

JistAPI.Proxiable, JistAPI.Timeless, SocketInterface, SocketInterface.TcpSocketInterface

public class TcpSocket
extends java.lang.Object
implements SocketInterface.TcpSocketInterface

SWANS Implementation of Socket entity.

Since:

SWANS1.0

Nested Class Summary

static class

TcpSocket.TcpSocketCallback Implementation of Socket Callback for TcpSocket.

Nested classes/interfaces inherited from interface jist.swans.trans.SocketInterface

SocketInterface.TcpServerSocketInterface, SocketInterface.TcpSocketInterface

Field Summary

static long	DELAYED_ACK_TIME Number of milliseconds to wait before sending an ACK.
static int	FULL_DEBUG Debug printing flag.
static int	INFO Debug printing flag.
static short	INIT_WINDOW_SIZE Initial window size.
static int	MSL Maximum Segment Lifetime.
static int	MSS Maximum Segment Size.
static int	OFF Debug printing flag.
static long	PERSIST_TIMER Number of seconds to wait before sending probe packets.
static int	PRINTOUT Indicator for printing debug outputs.
static long	RETRANSMIT_TIMEOUT Number of seconds to wait for first retransmission timer.
static long	RETRANSMIT_TIMEOUT_FINAL Number of seconds to wait for second retransmission timer.
static int	TCP_DEBUG Debug printing flag.

Constructor Summary

	TcpSocket() Creates an unconnected socket, with the system-default type of SocketImpl.
	TcpSocket(java.net.InetAddress address, int port) Creates a stream socket and connects it to the specified port number at the specified IP address.
	TcpSocket(java.net.InetAddress host, int port, boolean stream) Deprecated.
	TcpSocket(java.net.InetAddress address, int port, java.net.InetAddress localAddr, int localPort) Creates a socket and connects it to the specified remote address on the specified remote port.
protected	TcpSocket(java.net.SocketImpl impl) Creates an unconnected Socket with a user-specified SocketImpl.
	TcpSocket(java.lang.String host, int port) Creates a stream socket and connects it to the specified port number on the named host.
	TcpSocket(java.lang.String host, int port, boolean stream) Deprecated.
	TcpSocket(java.lang.String host, int port, java.net.InetAddress localAddr, int localPort) Creates a socket and connects it to the specified remote host on the specified remote port.
protected	TcpSocket(TransInterface.TransTcpInterface tcpEntity, java.net.InetAddress rAddr, short rPort, java.net.InetAddress lAddr, short lPort, int initialAckNum, short winSize) Creates an unconnected Socket with a user-specified TransInterface Entity and SYN packet received by TcpServerSocket.

Method Summary

void	_jistPostInit() Post-constructor call.
void	bind(java.net.SocketAddress bindpoint) Binds the ServerSocket to a specific address (IP address and port number).
void	checkPacketandState(TransTcp.TcpMessage msg, NetAddress src) Check and process the incoming packet depending on current state of the socket.
void	close() Closes this socket.
void	connect(java.net.SocketAddress endpoint) Connects this socket to the server.
void	connect(java.net.SocketAddress endpoint, int timeout) Connects this socket to the server with a specified timeout value.
void	constructPackets() Creates packets to be sent based on the receiver's advertised window (managing flow control).
void	createProxy() Create an entity reference to itself.
protected void	establishingConnection() this method is used to wait for incoming ACK packet for connection establishment.
byte[]	getBytesFromSocket(int length) This method is called by the input stream to retrieve data from the transport layer.
java.nio.channels.SocketChannel	getChannel() Returns the unique SocketChannel object associated with this socket, if any.
java.net.InetAddress	getInetAddress() Returns the local address of this server socket/socket.
InputStream	getInputStream() Returns an input stream for this socket.
boolean	getKeepAlive() Tests if SO_KEEPALIVE is enabled.
java.net.InetAddress	getLocalAddress() Gets the local address to which the socket is bound.
int	getLocalPort() Returns the port on which this socket is listening.
java.net.SocketAddress	getLocalSocketAddress() Returns the address of the endpoint this socket is bound to, or null if it is not bound yet.
boolean	getOOBInline() Tests if OOBINLINE is enabled.
OutputStream	getOutputStream() Returns an output stream for this socket.
int	getPort() Returns the remote port to which this socket is connected.
SocketInterface.TcpSocketInterface	getProxy() Returns the entity reference to the socket itself.
int	getReceiveBufferSize() Gets the value of the SO_RCVBUF option for this ServerSocket, that is the proposed buffer size that will be used for Sockets accepted from this ServerSocket.
java.net.SocketAddress	getRemoteSocketAddress() Returns the address of the endpoint this socket is connected to, or null if it is unconnected.
boolean	getReuseAddress() Tests if SO_REUSEADDR is enabled.
int	getSendBufferSize() Get value of the SO_SNDBUF option for this Socket, that is the buffer size used by the platform for output on this Socket.
int	getSoLinger() Returns setting for SO_LINGER.
int	getSoTimeout() Retrieve setting for SO_TIMEOUT.
boolean	getTcpNoDelay() Tests if TCP_NODELAY is enabled.
int	getTrafficClass() Gets traffic class or type-of-service in the IP header for packets sent from this Socket.
boolean	isBound() Returns the binding state of the ServerSocket.
boolean	isClosed() Returns the closed state of the ServerSocket.
boolean	isConnected() Returns the connection state of the socket.
boolean	isInputShutdown() Returns wether the read-half of the socket connection is closed.
boolean	isOutputShutdown() Returns wether the write-half of the socket connection is closed.
void	persistTimerTimeout(int timerId, int seqNum) Execution when persist timer times out (sending probe message).
protected void	printMessage(TransTcp.TcpMessage msg, boolean isReceive) Prints out the message header and payload.
int	queueBytes(byte[] data) This method is called to send bytes to the other side.
void	resetTimerTimeout(int timerId) Execution when reset timer times out (closing the socket).
void	retransmitTimerTimeout(int seqNum, long time) Attempt to retransmit because the timer times out.
protected TransTcp.TcpMessage	sendDataPacket(byte[] data) Send a packet to the remote socket.
protected void	sendFINPacket() A method to send FIN packet.
protected void	sendFirstACKPacket() A method to send ACK packet.
protected void	sendRSTPacket(int seqNum, int ackNum) A method to send RST packet.
protected void	sendSYNACKPacket() A method to send SYNACK packet.
protected void	sendSYNPacket() A method to send SYN packet.
void	sendUrgentData(int data) Send one byte of urgent data on the socket.
void	setKeepAlive(boolean on) Enable/disable SO_KEEPALIVE.
void	setOOBInline(boolean on) Enable/disable OOBINLINE (receipt of TCP urgent data) By default, this option is disabled and TCP urgent data received on a socket is silently discarded.
void	setReceiveBufferSize(int size) Sets a default proposed value for the SO_RCVBUF option for sockets accepted from this ServerSocket.
void	setReuseAddress(boolean on) Enable/disable the SO_REUSEADDR socket option.
void	setSendBufferSize(int size) Sets the SO_SNDBUF option to the specified value for this Socket.
static void	setSocketImplFactory(java.net.SocketImplFactory fac) Sets the client socket implementation factory for the application.
void	setSoLinger(boolean on, int linger) Enable/disable SO_LINGER with the specified linger time in seconds.
void	setSoTimeout(int timeout) Enable/disable SO_TIMEOUT with the specified timeout, in milliseconds.
void	setTcpEntity(TransInterface.TransTcpInterface tcpEntity) Sets the reference to the network layer.
void	setTcpNoDelay(boolean on) Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).
void	setTrafficClass(int tc) Sets traffic class or type-of-service octet in the IP header for packets sent from this Socket.
void	shutdownInput() Places the input stream for this socket at "end of stream".
void	shutdownOutput() Disables the output stream for this socket.
void	startPersistTimer(int seqNum) Methods for persist timer (sender sending packets to probe receiver window).
void	startResetTimer() Methods for reset timer (this timer is used when establishing or closing connection --> If no reply is received, connection is reset).
void	startRetransmitTimer(int seqNum, long time) Schedule a retransmission for a message.
void	startTimeWaitTimer() Methods for timer during TIME_WAIT state.
void	timeWaitTimerTimeout() Execution when time wait timer times out (closing the socket).
java.lang.String	toString() Returns the implementation address and implementation port of this socket as a String.

Methods inherited from class java.lang.Object

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

Field Detail

OFF

public static final int OFF

Debug printing flag. OFF = no debug output

See Also:

Constant Field Values

INFO

public static final int INFO

Debug printing flag. INFO = minimum debug output

See Also:

Constant Field Values

TCP_DEBUG

public static final int TCP_DEBUG

Debug printing flag. TCP_DEBUG = debug output, showing only packet traffic

See Also:

Constant Field Values

FULL_DEBUG

public static final int FULL_DEBUG

Debug printing flag. FULL_DEBUG = full debug output

See Also:

Constant Field Values

PRINTOUT

public static final int PRINTOUT

Indicator for printing debug outputs.

See Also:

Constant Field Values

MSS

public static final int MSS

Maximum Segment Size. Number of bytes to transfer in one packet.

See Also:

Constant Field Values

MSL

public static final int MSL

Maximum Segment Lifetime. Maximum amount of time any segment can exist in the network before being discarded. (Can be 30 seconds, 1 minute, or 2 minutes) (TCP has to wait for 2*MSL before the socket pair (client IP address, client port number, server IP address, and server port number) can be reused)

See Also:

Constant Field Values

DELAYED_ACK_TIME

public static final long DELAYED_ACK_TIME

Number of milliseconds to wait before sending an ACK.

See Also:

Constant Field Values

RETRANSMIT_TIMEOUT

public static final long RETRANSMIT_TIMEOUT

Number of seconds to wait for first retransmission timer.

See Also:

Constant Field Values

RETRANSMIT_TIMEOUT_FINAL

public static final long RETRANSMIT_TIMEOUT_FINAL

Number of seconds to wait for second retransmission timer.

See Also:

Constant Field Values

PERSIST_TIMER

public static final long PERSIST_TIMER

Number of seconds to wait before sending probe packets. This happens when receiver is advertising zero window.

See Also:

Constant Field Values

INIT_WINDOW_SIZE

public static final short INIT_WINDOW_SIZE

Initial window size.

See Also:

Constant Field Values

Constructor Detail

TcpSocket

public TcpSocket()

Creates an unconnected socket, with the system-default type of SocketImpl.

TcpSocket

public TcpSocket(java.net.InetAddress address,
                 int port)

Creates a stream socket and connects it to the specified port number at the specified IP address.

Parameters:

address - the IP address

port - the port number

TcpSocket

public TcpSocket(java.net.InetAddress host,
                 int port,
                 boolean stream)

Deprecated. Use DatagramSocket instead for UDP transport.

Parameters:

host - the IP address

port - the port number

stream - if true, create a stream socket; otherwise, create a datagram socket.

TcpSocket

public TcpSocket(java.net.InetAddress address,
                 int port,
                 java.net.InetAddress localAddr,
                 int localPort)

Creates a socket and connects it to the specified remote address on the specified remote port.

Parameters:

address - the remote address

port - the remote port

localAddr - the local address the socket is bound to

localPort - the local port the socket is bound to

TcpSocket

protected TcpSocket(java.net.SocketImpl impl)

Creates an unconnected Socket with a user-specified SocketImpl.

Parameters:

impl - an instance of a SocketImpl the subclass wishes to use on the Socket

TcpSocket

protected TcpSocket(TransInterface.TransTcpInterface tcpEntity,
                    java.net.InetAddress rAddr,
                    short rPort,
                    java.net.InetAddress lAddr,
                    short lPort,
                    int initialAckNum,
                    short winSize)

Creates an unconnected Socket with a user-specified TransInterface Entity and SYN packet received by TcpServerSocket.

Parameters:

tcpEntity - entity reference to transport layer

rAddr - remote address

rPort - remote port number

lAddr - local address

lPort - local port number

initialAckNum - initial acknowledgement number

winSize - the other side's receiver window size

TcpSocket

public TcpSocket(java.lang.String host,
                 int port)

Creates a stream socket and connects it to the specified port number on the named host.

Parameters:

host - the host name, or null for the loopback address.

port - the port number.

TcpSocket

public TcpSocket(java.lang.String host,
                 int port,
                 boolean stream)

Deprecated. Use DatagramSocket instead for UDP transport.

Parameters:

host - the host name, or null for the loopback address.

port - the port number.

stream - a boolean indicating whether this is a stream socket or a datagram socket.

TcpSocket

public TcpSocket(java.lang.String host,
                 int port,
                 java.net.InetAddress localAddr,
                 int localPort)

Creates a socket and connects it to the specified remote host on the specified remote port.

Parameters:

host - the name of the remote host, or null for the loopback address.

port - the remote port

localAddr - the local address the socket is bound to

localPort - the local port the socket is bound to

Method Detail

createProxy

public void createProxy()

Create an entity reference to itself.

getProxy

public SocketInterface.TcpSocketInterface getProxy()

Returns the entity reference to the socket itself.

Returns:

Entity reference to TcpSocket

setTcpEntity

public void setTcpEntity(TransInterface.TransTcpInterface tcpEntity)

Sets the reference to the network layer.

Specified by:

setTcpEntity in interface SocketInterface

Parameters:

tcpEntity - entity reference to transport layer

_jistPostInit

public void _jistPostInit()

Post-constructor call. Since constructors can not be blocking (JiST/Java limitation), we rewrite a regular socket constructor to two calls. This is the second one, and it can be blocking, because it is a regular method.

Specified by:

_jistPostInit in interface SocketInterface

bind

public void bind(java.net.SocketAddress bindpoint)

Binds the ServerSocket to a specific address (IP address and port number).

Specified by:

bind in interface SocketInterface

Parameters:

bindpoint - The IP address & port number to bind to.

close

public void close()

Closes this socket.

Specified by:

close in interface SocketInterface

connect

public void connect(java.net.SocketAddress endpoint)

Connects this socket to the server.

Specified by:

connect in interface SocketInterface.TcpSocketInterface

Parameters:

endpoint - the SocketAddress

connect

public void connect(java.net.SocketAddress endpoint,
                    int timeout)

Connects this socket to the server with a specified timeout value.

Specified by:

connect in interface SocketInterface.TcpSocketInterface

Parameters:

endpoint - the SocketAddress

timeout - the timeout value to be used in milliseconds

getChannel

public java.nio.channels.SocketChannel getChannel()

Returns the unique SocketChannel object associated with this socket, if any.

Specified by:

getChannel in interface SocketInterface.TcpSocketInterface

Returns:

the socket channel associated with this socket, or null if this socket was not created for a channel

getInetAddress

public java.net.InetAddress getInetAddress()

Returns the local address of this server socket/socket.

Specified by:

getInetAddress in interface SocketInterface

Returns:

the address to which this socket is bound, or null if the socket is unbound.

getInputStream

public InputStream getInputStream()

Returns an input stream for this socket.

Specified by:

getInputStream in interface SocketInterface.TcpSocketInterface

Returns:

an input stream for reading bytes from this socket.

getKeepAlive

public boolean getKeepAlive()

Tests if SO_KEEPALIVE is enabled.

Specified by:

getKeepAlive in interface SocketInterface.TcpSocketInterface

Returns:

a boolean indicating whether or not SO_KEEPALIVE is enabled.

getLocalAddress

public java.net.InetAddress getLocalAddress()

Gets the local address to which the socket is bound.

Specified by:

getLocalAddress in interface SocketInterface.TcpSocketInterface

Returns:

the local address to which the socket is bound or InetAddress.anyLocalAddress() if the socket is not bound yet.

getLocalPort

public int getLocalPort()

Returns the port on which this socket is listening.

Specified by:

getLocalPort in interface SocketInterface

Returns:

the port number to which this socket is listening or -1 if the socket is not bound yet.

getLocalSocketAddress

public java.net.SocketAddress getLocalSocketAddress()

Returns the address of the endpoint this socket is bound to, or null if it is not bound yet.

Specified by:

getLocalSocketAddress in interface SocketInterface

Returns:

a SocketAddress representing the local endpoint of this socket, or null if it is not bound yet.

getOOBInline

public boolean getOOBInline()

Tests if OOBINLINE is enabled.

Specified by:

getOOBInline in interface SocketInterface.TcpSocketInterface

Returns:

a boolean indicating whether or not OOBINLINE is enabled.

getOutputStream

public OutputStream getOutputStream()

Returns an output stream for this socket.

Specified by:

getOutputStream in interface SocketInterface.TcpSocketInterface

Returns:

an output stream for writing bytes to this socket.

getPort

public int getPort()

Returns the remote port to which this socket is connected.

Specified by:

getPort in interface SocketInterface.TcpSocketInterface

Returns:

the remote port number to which this socket is connected, or 0 if the socket is not connected yet.

getReceiveBufferSize

public int getReceiveBufferSize()

Gets the value of the SO_RCVBUF option for this ServerSocket, that is the proposed buffer size that will be used for Sockets accepted from this ServerSocket.

Specified by:

getReceiveBufferSize in interface SocketInterface

Returns:

the value of the SO_RCVBUF option for this Socket.

getRemoteSocketAddress

public java.net.SocketAddress getRemoteSocketAddress()

Returns the address of the endpoint this socket is connected to, or null if it is unconnected.

Specified by:

getRemoteSocketAddress in interface SocketInterface.TcpSocketInterface

Returns:

a SocketAddress representing the local endpoint of this socket, or null if it is not bound yet.

getReuseAddress

public boolean getReuseAddress()

Tests if SO_REUSEADDR is enabled.

Specified by:

getReuseAddress in interface SocketInterface

Returns:

a boolean indicating whether or not SO_REUSEADDR is enabled.

getSendBufferSize

public int getSendBufferSize()

Get value of the SO_SNDBUF option for this Socket, that is the buffer size used by the platform for output on this Socket.

Specified by:

getSendBufferSize in interface SocketInterface.TcpSocketInterface

Returns:

the value of the SO_SNDBUF option for this Socket.

getSoLinger

public int getSoLinger()

Returns setting for SO_LINGER.

Specified by:

getSoLinger in interface SocketInterface.TcpSocketInterface

Returns:

the setting for SO_LINGER.

getSoTimeout

public int getSoTimeout()

Retrieve setting for SO_TIMEOUT.

Specified by:

getSoTimeout in interface SocketInterface

Returns:

the SO_TIMEOUT value

getTcpNoDelay

public boolean getTcpNoDelay()

Tests if TCP_NODELAY is enabled.

Specified by:

getTcpNoDelay in interface SocketInterface.TcpSocketInterface

Returns:

a boolean indicating whether or not TCP_NODELAY is enabled.

getTrafficClass

public int getTrafficClass()

Gets traffic class or type-of-service in the IP header for packets sent from this Socket.

Specified by:

getTrafficClass in interface SocketInterface.TcpSocketInterface

Returns:

the traffic class or type-of-service already set

isBound

public boolean isBound()

Returns the binding state of the ServerSocket.

Specified by:

isBound in interface SocketInterface

Returns:

true if the ServerSocket succesfuly bound to an address

isClosed

public boolean isClosed()

Returns the closed state of the ServerSocket.

Specified by:

isClosed in interface SocketInterface

Returns:

true if the socket has been closed

isConnected

public boolean isConnected()

Returns the connection state of the socket.

Specified by:

isConnected in interface SocketInterface.TcpSocketInterface

Returns:

true if the socket successfuly connected to a server

isInputShutdown

public boolean isInputShutdown()

Returns wether the read-half of the socket connection is closed.

Specified by:

isInputShutdown in interface SocketInterface.TcpSocketInterface

Returns:

true if the input of the socket has been shutdown

isOutputShutdown

public boolean isOutputShutdown()

Returns wether the write-half of the socket connection is closed.

Specified by:

isOutputShutdown in interface SocketInterface.TcpSocketInterface

Returns:

true if the output of the socket has been shutdown

sendUrgentData

public void sendUrgentData(int data)

Send one byte of urgent data on the socket.

Specified by:

sendUrgentData in interface SocketInterface.TcpSocketInterface

Parameters:

data - The byte of data to send

setKeepAlive

public void setKeepAlive(boolean on)

Enable/disable SO_KEEPALIVE.

Specified by:

setKeepAlive in interface SocketInterface.TcpSocketInterface

Parameters:

on - whether or not to have socket keep alive turned on

setOOBInline

public void setOOBInline(boolean on)

Enable/disable OOBINLINE (receipt of TCP urgent data) By default, this option is disabled and TCP urgent data received on a socket is silently discarded.

Specified by:

setOOBInline in interface SocketInterface.TcpSocketInterface

Parameters:

on - true to enable OOBINLINE, false to disable.

setReceiveBufferSize

public void setReceiveBufferSize(int size)

Sets a default proposed value for the SO_RCVBUF option for sockets accepted from this ServerSocket.

Specified by:

setReceiveBufferSize in interface SocketInterface

Parameters:

size - the size to which to set the receive buffer size. This value must be greater than 0.

setReuseAddress

public void setReuseAddress(boolean on)

Enable/disable the SO_REUSEADDR socket option.

Specified by:

setReuseAddress in interface SocketInterface

Parameters:

on - whether to enable or disable the socket option

setSendBufferSize

public void setSendBufferSize(int size)

Sets the SO_SNDBUF option to the specified value for this Socket.

Specified by:

setSendBufferSize in interface SocketInterface.TcpSocketInterface

Parameters:

size - the size to which to set the send buffer size. This value must be greater than 0.

setSocketImplFactory

public static void setSocketImplFactory(java.net.SocketImplFactory fac)

Sets the client socket implementation factory for the application.

Parameters:

fac - the desired factory

setSoLinger

public void setSoLinger(boolean on,
                        int linger)

Enable/disable SO_LINGER with the specified linger time in seconds.

Specified by:

setSoLinger in interface SocketInterface.TcpSocketInterface

Parameters:

on - whether or not to linger on.

linger - how long to linger for, if on is true.

setSoTimeout

public void setSoTimeout(int timeout)

Enable/disable SO_TIMEOUT with the specified timeout, in milliseconds.

Specified by:

setSoTimeout in interface SocketInterface

Parameters:

timeout - the specified timeout, in milliseconds

setTcpNoDelay

public void setTcpNoDelay(boolean on)

Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).

Specified by:

setTcpNoDelay in interface SocketInterface.TcpSocketInterface

Parameters:

on - true to enable TCP_NODELAY, false to disable.

setTrafficClass

public void setTrafficClass(int tc)

Sets traffic class or type-of-service octet in the IP header for packets sent from this Socket.

Specified by:

setTrafficClass in interface SocketInterface.TcpSocketInterface

Parameters:

tc - an int value for the bitset.

shutdownInput

public void shutdownInput()
                   throws java.io.IOException

Places the input stream for this socket at "end of stream".

Specified by:

shutdownInput in interface SocketInterface.TcpSocketInterface

Throws:

java.io.IOException - if an I/O error occurs when shutting down this socket.

shutdownOutput

public void shutdownOutput()
                    throws java.io.IOException

Disables the output stream for this socket.

Specified by:

shutdownOutput in interface SocketInterface.TcpSocketInterface

Throws:

java.io.IOException - if an I/O error occurs when shutting down this socket.

toString

public java.lang.String toString()

Returns the implementation address and implementation port of this socket as a String.

Specified by:

toString in interface SocketInterface

Overrides:

toString in class java.lang.Object

Returns:

a string representation of this socket.

establishingConnection

protected void establishingConnection()

this method is used to wait for incoming ACK packet for connection establishment.

printMessage

protected void printMessage(TransTcp.TcpMessage msg,
                            boolean isReceive)

Prints out the message header and payload.

Parameters:

msg - TCP message to print out

isReceive - true if printing for receiving side

sendSYNPacket

protected void sendSYNPacket()

A method to send SYN packet.

sendSYNACKPacket

protected void sendSYNACKPacket()

A method to send SYNACK packet.

sendFirstACKPacket

protected void sendFirstACKPacket()

A method to send ACK packet.

sendFINPacket

protected void sendFINPacket()

A method to send FIN packet.

sendRSTPacket

protected void sendRSTPacket(int seqNum,
                             int ackNum)

A method to send RST packet.

Parameters:

seqNum - sequence number

ackNum - acknowledgement number

sendDataPacket

protected TransTcp.TcpMessage sendDataPacket(byte[] data)

Send a packet to the remote socket. To send an ACK packet, set data to null.

Parameters:

data - data to send

Returns:

sent packet

constructPackets

public void constructPackets()

Creates packets to be sent based on the receiver's advertised window (managing flow control).

Specified by:

constructPackets in interface SocketInterface.TcpSocketInterface

queueBytes

public int queueBytes(byte[] data)

This method is called to send bytes to the other side. What this method does is storing the bytes in the send buffer and then call sendPackets method to send the bytes.

Specified by:

queueBytes in interface SocketInterface.TcpSocketInterface

Parameters:

data - bytes to be stored in the send buffer

Returns:

the number of bytes actually stored

getBytesFromSocket

public byte[] getBytesFromSocket(int length)

This method is called by the input stream to retrieve data from the transport layer.

Specified by:

getBytesFromSocket in interface SocketInterface.TcpSocketInterface

Parameters:

length - number of bytes to retrieve

Returns:

byte array containing data from socket

startRetransmitTimer

public void startRetransmitTimer(int seqNum,
                                 long time)

Schedule a retransmission for a message.

Specified by:

startRetransmitTimer in interface SocketInterface.TcpSocketInterface

Parameters:

seqNum - sequence number of message to retransmit

time - wait time before attempting to retransmit

retransmitTimerTimeout

public void retransmitTimerTimeout(int seqNum,
                                   long time)

Attempt to retransmit because the timer times out.

Specified by:

retransmitTimerTimeout in interface SocketInterface.TcpSocketInterface

Parameters:

seqNum - sequence number of message to retransmit

time - wait time before attempting to retransmit

startPersistTimer

public void startPersistTimer(int seqNum)

Methods for persist timer (sender sending packets to probe receiver window).

Specified by:

startPersistTimer in interface SocketInterface.TcpSocketInterface

Parameters:

seqNum - number of the probe message

persistTimerTimeout

public void persistTimerTimeout(int timerId,
                                int seqNum)

Execution when persist timer times out (sending probe message).

Specified by:

persistTimerTimeout in interface SocketInterface.TcpSocketInterface

Parameters:

timerId - ID of the persist timer

seqNum - number of the probe message

startResetTimer

public void startResetTimer()

Methods for reset timer (this timer is used when establishing or closing connection --> If no reply is received, connection is reset).

Specified by:

startResetTimer in interface SocketInterface.TcpSocketInterface

resetTimerTimeout

public void resetTimerTimeout(int timerId)

Execution when reset timer times out (closing the socket).

Specified by:

resetTimerTimeout in interface SocketInterface.TcpSocketInterface

Parameters:

timerId - ID of the reset timer

startTimeWaitTimer

public void startTimeWaitTimer()

Methods for timer during TIME_WAIT state.

Specified by:

startTimeWaitTimer in interface SocketInterface.TcpSocketInterface

timeWaitTimerTimeout

public void timeWaitTimerTimeout()

Execution when time wait timer times out (closing the socket).

Specified by:

timeWaitTimerTimeout in interface SocketInterface.TcpSocketInterface

checkPacketandState

public void checkPacketandState(TransTcp.TcpMessage msg,
                                NetAddress src)

Check and process the incoming packet depending on current state of the socket.

Specified by:

checkPacketandState in interface SocketInterface

Parameters:

msg - the incoming TCP message

src - source of packet