jist.swans.trans
Class TransTcp.TcpMessage

java.lang.Object
  jist.swans.trans.TransInterface.TransMessage
      jist.swans.trans.TransTcp.TcpMessage

All Implemented Interfaces:

JistAPI.Timeless, Message

Enclosing class:

TransTcp

public static class TransTcp.TcpMessage
extends TransInterface.TransMessage

Data structure for TCP Message. TCP Packet header: srcPort : 2 dstPort : 2 seqNum : 4 ackNum : 4 offset and flags : 2 window size : 2 checksum : 2 urgent pointer : 2 TOTAL HEADER SIZE : 20 options : variable data : variable

Field Summary

private int	ackNum 32 bit acknowledgement number.
private short	dstPort 16 bit destination port number.
private short	errorChecksum checksum.
static int	HEADER_SIZE Minimum size of TCP message.
private short	offsetAndFlags 16 bit offset and flags.
private TransTcp.TcpOptions	options options field (contains padding to make this field 32 bit boundary).
private Message	payload data.
private int	seqNum 32 bit sequence number of first data octet in this segment.
private short	srcPort 16-bit source port number.
private short	urgentPointer current value of the urgent pointer as a positive offset from the sequence number.
private short	windowSize 16 bit window size (number of data octets to be accepted).

Fields inherited from interface jist.swans.misc.Message

NULL

Constructor Summary

TransTcp.TcpMessage(byte[] data, int offset)
constructor for TcpMessage (reconstruct TcpMessage from byte array).

TransTcp.TcpMessage(short srcPort, short dstPort, int seqNum, int ackNum, short offset, boolean URG, boolean ACK, boolean PSH, boolean RST, boolean SYN, boolean FIN, short windowSize, Message data)
constructor for TcpMessage.

Method Summary

static TransTcp.TcpMessage	createACKPacket(int sourcePort, int destPort, int seqNumber, int ackNumber, short windowSize) Method called to create an ACK packet.
static TransTcp.TcpMessage	createFINPacket(int sourcePort, int destPort, int seqNumber, int ackNumber, short windowSize) Method called to create a FIN packet.
static TransTcp.TcpMessage	createRSTPacket(int sourcePort, int destPort, int seqNumber, int ackNumber, short windowSize) Method called to create a RST packet.
static TransTcp.TcpMessage	createSYNACKPacket(int sourcePort, int destPort, int seqNumber, int ackNumber, short windowSize) Method called to create a SYNACK packet.
static TransTcp.TcpMessage	createSYNPacket(int sourcePort, int destPort, int seqNumber, short windowSize) Method called to create a SYN packet.
boolean	getACK() Accessor for ACK flag.
int	getAckNum() Accessor for acknowledgement number.
void	getBytes(byte[] msg, int offset) Retrieves the message in byte array.
short	getDstPort() Accessor for destination port.
boolean	getFIN() Accessor for FIN flag.
short	getOffset() Accessor for offset in the message.
TransTcp.TcpOptions	getOptions() Accessor for options.
Message	getPayload() Accessor for payload.
boolean	getPSH() Accessor for PSH flag.
boolean	getRST() Accessor for RST flag.
int	getSeqNum() Accessor for sequence number.
int	getSize() Returns the size of the TCP message.
short	getSrcPort() Accessor for source port.
boolean	getSYN() Accessor for SYN flag.
boolean	getURG() Accessor for URGENT flag.
short	getWindowSize() Accessor for window size.
void	printMessage() Prints out the message header with zero tabs.
void	printMessage(int numTabs) Prints out the message header.
void	printMessage(int numTabs, boolean isPrintPayload) Prints out the message header and payload.
java.lang.String	toString() Returns string representation of the TCP message.

Methods inherited from class java.lang.Object

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

Field Detail

HEADER_SIZE

public static final int HEADER_SIZE

Minimum size of TCP message.

See Also:

Constant Field Values

srcPort

private short srcPort

16-bit source port number.

dstPort

private short dstPort

16 bit destination port number.

seqNum

private int seqNum

32 bit sequence number of first data octet in this segment.

ackNum

private int ackNum

32 bit acknowledgement number.

offsetAndFlags

private short offsetAndFlags

16 bit offset and flags. this contains: 4 bit data offset (number of 32 bit words in the TCP header) 6 bit reserved 1 bit URG - urgent pointer field significant 1 bit ACK - acknowledgement field significant 1 bit PSH - push function 1 bit RST - reset the connection 1 bit SYN - synchronize sequence numbers 1 bit FIN - no more data from sender

windowSize

private short windowSize

16 bit window size (number of data octets to be accepted).

errorChecksum

private short errorChecksum

checksum.

urgentPointer

private short urgentPointer

current value of the urgent pointer as a positive offset from the sequence number.

options

private TransTcp.TcpOptions options

options field (contains padding to make this field 32 bit boundary).

payload

private Message payload

data.

Constructor Detail

TransTcp.TcpMessage

public TransTcp.TcpMessage(short srcPort,
                           short dstPort,
                           int seqNum,
                           int ackNum,
                           short offset,
                           boolean URG,
                           boolean ACK,
                           boolean PSH,
                           boolean RST,
                           boolean SYN,
                           boolean FIN,
                           short windowSize,
                           Message data)

constructor for TcpMessage.

Parameters:

srcPort - source port number

dstPort - destination port number

seqNum - sequence number

ackNum - acknowledgement number

offset - data offset (start of data in the header; used when the packet has options)

URG - urgent flag

ACK - acknowledgement flag

PSH - push flag

RST - reset flag

SYN - SYN flag

FIN - FIN flag

windowSize - size of receiving window

data - data

TransTcp.TcpMessage

public TransTcp.TcpMessage(byte[] data,
                           int offset)

constructor for TcpMessage (reconstruct TcpMessage from byte array).

Parameters:

data - array containing TCP message

offset - start index to read the array

Method Detail

createSYNPacket

public static TransTcp.TcpMessage createSYNPacket(int sourcePort,
                                                  int destPort,
                                                  int seqNumber,
                                                  short windowSize)

Method called to create a SYN packet.

Parameters:

sourcePort - source port number

destPort - destination port number

seqNumber - sequence number

windowSize - size of receiving window

Returns:

SYN packet

createSYNACKPacket

public static TransTcp.TcpMessage createSYNACKPacket(int sourcePort,
                                                     int destPort,
                                                     int seqNumber,
                                                     int ackNumber,
                                                     short windowSize)

Method called to create a SYNACK packet.

Parameters:

sourcePort - source port number

destPort - destination port number

seqNumber - sequence number

ackNumber - acknowledgement number

windowSize - size of receiving window

Returns:

SYNACK packet

createACKPacket

public static TransTcp.TcpMessage createACKPacket(int sourcePort,
                                                  int destPort,
                                                  int seqNumber,
                                                  int ackNumber,
                                                  short windowSize)

Method called to create an ACK packet.

Parameters:

sourcePort - source port number

destPort - destination port number

seqNumber - sequence number

ackNumber - acknowledgement number

windowSize - size of receiving window

Returns:

first ACK packet (ACK for SYNACK packet)

createFINPacket

public static TransTcp.TcpMessage createFINPacket(int sourcePort,
                                                  int destPort,
                                                  int seqNumber,
                                                  int ackNumber,
                                                  short windowSize)

Method called to create a FIN packet.

Parameters:

sourcePort - source port number

destPort - destination port number

seqNumber - sequence number

ackNumber - acknowledgement number

windowSize - size of receiving window

Returns:

FIN packet

createRSTPacket

public static TransTcp.TcpMessage createRSTPacket(int sourcePort,
                                                  int destPort,
                                                  int seqNumber,
                                                  int ackNumber,
                                                  short windowSize)

Method called to create a RST packet.

Parameters:

sourcePort - source port number

destPort - destination port number

seqNumber - sequence number

ackNumber - acknowledgement number

windowSize - size of receiving window

Returns:

RST packet

getSrcPort

public short getSrcPort()

Accessor for source port.

Returns:

source port

getDstPort

public short getDstPort()

Accessor for destination port.

Returns:

destination port

getSeqNum

public int getSeqNum()

Accessor for sequence number.

Returns:

sequence number

getAckNum

public int getAckNum()

Accessor for acknowledgement number.

Returns:

acknowledgement number

getOffset

public short getOffset()

Accessor for offset in the message.

Returns:

offset from the beginning to header to data

getURG

public boolean getURG()

Accessor for URGENT flag.

Returns:

state of the URG flag (true if flag is set)

getACK

public boolean getACK()

Accessor for ACK flag.

Returns:

state of the ACK flag (true if flag is set)

getPSH

public boolean getPSH()

Accessor for PSH flag.

Returns:

state of the PSH flag (true if flag is set)

getRST

public boolean getRST()

Accessor for RST flag.

Returns:

state of the RST flag (true if flag is set)

getSYN

public boolean getSYN()

Accessor for SYN flag.

Returns:

state of the SYN flag (true if flag is set)

getFIN

public boolean getFIN()

Accessor for FIN flag.

Returns:

state of the FIN flag (true if flag is set)

getWindowSize

public short getWindowSize()

Accessor for window size.

Returns:

window size

getOptions

public TransTcp.TcpOptions getOptions()

Accessor for options.

Returns:

TcpOptions object

getPayload

public Message getPayload()

Accessor for payload.

Returns:

payload

getSize

public int getSize()

Returns the size of the TCP message.

Returns:

size of message

getBytes

public void getBytes(byte[] msg,
                     int offset)

Retrieves the message in byte array.

Parameters:

msg - byte array to store the message

offset - start index of the destination array

toString

public java.lang.String toString()

Returns string representation of the TCP message.

Overrides:

toString in class java.lang.Object

Returns:

string representation of the message

printMessage

public void printMessage(int numTabs,
                         boolean isPrintPayload)

Prints out the message header and payload.

Parameters:

numTabs - number of tabs

isPrintPayload - set to true to print out payload in message

printMessage

public void printMessage()

Prints out the message header with zero tabs.

printMessage

public void printMessage(int numTabs)

Prints out the message header.

Parameters:

numTabs - number of tabs