fr.gedeon.telnetservice
Class Session

java.lang.Object
  fr.gedeon.telnetservice.Session

All Implemented Interfaces:

Runnable

public class Session
extends Object
implements Runnable

The Telnet Session is the main engine for a telnet connection; it handles inputs and outputs, keeping telnet state, responding to telnet specific commands, and notifies the Telnet Session Controller of important events (such as client input, client screen resize, etc) through the available notify* methods of ActionListeners provided by registered TelnetServiceExtension.

The typical connection life cycle is as follows:

1. The Telnet Session is created by the Telnet Service when it receives an incoming connection, it is initialized as described above;
2. The Telnet Session creates a SessionState instance. Only one state is created per session. It included in most calls from the session, and allows the integrating components to store their state;
3. The Telnet Session goes through the telnet options negociation, and interacts with the service extensions for the behavioral features;
4. When initial telnet setup and negociation is done (there can be further telnet messaging during the session), registered SessionListeners are notified that the connection was established; this means that interaction with the user is going to start as of that point.
   (hint: this is a good place to display a 'welcome' message, or a notification of, say, the number of messages in their inbox ;-)
5. The next steps are repeated through the rest of the life-cycle of the Telnet Session (until a call to Telnet Session State isActive method returns false; at which point the connection is terminated and the Session is stopped).
6. The prompt is displayed to the user;
7. The user enters text, arrows, ctrl-char, or a trigger character;
8. The Action Listeners are notified of the entered text. Depending on the telnet client capabilities, and also on the Telnet Session configuration, the text entered may either be on a line-by-line or character-by-character basis -- the Telnet Session will attempt to setup character-by-character interaction by default and act as a filter to the remainder of the application; however, if the telnet client does not accept this request, key based triggers other than a new line may not be received.
9. The integrating application may spontaneously instruct the Session on its behavior at anytime, using the Session State provided methods.

Note that the core classes of this service library do not separate between login, password, and different state-based prompts; it is up to each Action Listener and Prompt Decorator to know what to display based on its Session State properties. The Action Listeners will also need to instruct the Console Delegate to suppress echo when it is expecting the user to type a password, for example. (this is done through ConsoleDelegate.setSuppressOutput(boolean).
Note: The telnetservice-jaas implementation of the Telnet Session Controller that is JAAS compliant and that takes care of the login procedure if it is needed by the configured LoginModule.

Author:

wgedeon

Field Summary

static int	CHAR_BACKSPACE
static int	CHAR_ESC
static int	CHAR_TAB
protected Thread	current The session thread
static String	implementedOptions Byte array of telnet options we can and want to negociate about, all other commands will result in a DONT or WONT response. Those implemented so far are: TELNET_OPTION_TOGGLEFLOWCONTROL TELNET_OPTION_LINEMODE TELNET_OPTION_WINDOWSIZE TELNET_OPTION_TERMINAL_TYPE TELNET_OPTION_ECHO
protected InputStream	input The connection socket input stream
protected OutputStream	output The connection socket output stream
protected Socket	socket The connection socket
static int	TELNET_AYT Are you there: Send back to the NVT some visible evidence that the AYT was received.
static int	TELNET_DO
static int	TELNET_DONT
static int	TELNET_EC Erase character: The receiver should delete the last preceding undeleted character from the data stream.
static int	TELNET_GA
static int	TELNET_IAC
static int	TELNET_NOP
static byte	TELNET_OPTION_ECHO
static byte	TELNET_OPTION_LINEMODE
static byte	TELNET_OPTION_LINEMODE_FORWARDMASK
static byte	TELNET_OPTION_LINEMODE_MODE
static byte	TELNET_OPTION_LINEMODE_MODE_EDIT
static byte	TELNET_OPTION_LINEMODE_MODE_LIT_ECHO
static byte	TELNET_OPTION_LINEMODE_MODE_MODE_ACK
static byte	TELNET_OPTION_LINEMODE_MODE_SOFT_TAB
static byte	TELNET_OPTION_LINEMODE_MODE_TRAPSIG
static byte	TELNET_OPTION_SUPRESSGOAHEAD
static byte	TELNET_OPTION_TERMINAL_TYPE
static byte	TELNET_OPTION_TERMINAL_TYPE_IS
static byte	TELNET_OPTION_TERMINAL_TYPE_SEND
static byte	TELNET_OPTION_TOGGLEFLOWCONTROL
static byte	TELNET_OPTION_WINDOWSIZE
static int	TELNET_SB
static int	TELNET_SE
static byte[]	TELNET_SEQUENCE_GOAHEAD
static int	TELNET_WILL
static int	TELNET_WONT

Method Summary

void	addSessionListener(SessionListener listener)
protected void	appendActiveText(char c)
protected void	appendActiveText(String txt, int offsetUpdateMask)
void	backspaceActiveText(int count)
protected void	close() Close all connections
protected void	commitActiveText()
Date	getConnectionTimestamp()
ConsoleDelegate	getConsoleDelegate()
OutputFormat	getOutputFormat()
SocketAddress	getRemoteSocketAddress()
SessionState	getSessionState()
void	notifyConnectionEstablished(SessionState sessionState)
void	notifyConnectionLost(SessionState sessionState)
void	output(SessionState sessionState, Object subject) Shortcut method for calling the session's OutputFormat to format the subject then calling the ConsoleDelegate to write the outcome to the console.
void	removeAllSessionListeners()
void	removeSessionListener(SessionListener listener)
protected void	replaceActiveText(String txt, int offsetUpdateMask)
void	run() Session run main loop
void	start() Start the session daemon: setup telnet options, then start the input processing.
void	stop() Stop this session
protected void	write(byte[] bbuf, int off, int len)
protected void	write(char[] cbuf, int off, int len)
protected void	write(String txt)
protected void	writeln(String txt)
protected void	writePrompt()

Methods inherited from class java.lang.Object

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

Field Detail

socket

protected Socket socket

The connection socket

current

protected Thread current

The session thread

input

protected InputStream input

The connection socket input stream

output

protected OutputStream output

The connection socket output stream

CHAR_BACKSPACE

public static final int CHAR_BACKSPACE

See Also:

Constant Field Values

CHAR_TAB

public static final int CHAR_TAB

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Constant Field Values

CHAR_ESC

public static final int CHAR_ESC

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Constant Field Values

TELNET_OPTION_ECHO

public static final byte TELNET_OPTION_ECHO

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Constant Field Values

TELNET_OPTION_SUPRESSGOAHEAD

public static final byte TELNET_OPTION_SUPRESSGOAHEAD

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Constant Field Values

TELNET_OPTION_TERMINAL_TYPE

public static final byte TELNET_OPTION_TERMINAL_TYPE

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Constant Field Values

TELNET_OPTION_TERMINAL_TYPE_IS

public static final byte TELNET_OPTION_TERMINAL_TYPE_IS

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Constant Field Values

TELNET_OPTION_TERMINAL_TYPE_SEND

public static final byte TELNET_OPTION_TERMINAL_TYPE_SEND

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Constant Field Values

TELNET_OPTION_WINDOWSIZE

public static final byte TELNET_OPTION_WINDOWSIZE

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Constant Field Values

TELNET_OPTION_TOGGLEFLOWCONTROL

public static final byte TELNET_OPTION_TOGGLEFLOWCONTROL

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Constant Field Values

TELNET_OPTION_LINEMODE

public static final byte TELNET_OPTION_LINEMODE

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Constant Field Values

TELNET_OPTION_LINEMODE_MODE

public static final byte TELNET_OPTION_LINEMODE_MODE

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Constant Field Values

TELNET_OPTION_LINEMODE_MODE_EDIT

public static final byte TELNET_OPTION_LINEMODE_MODE_EDIT

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Constant Field Values

TELNET_OPTION_LINEMODE_MODE_TRAPSIG

public static final byte TELNET_OPTION_LINEMODE_MODE_TRAPSIG

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Constant Field Values

TELNET_OPTION_LINEMODE_MODE_MODE_ACK

public static final byte TELNET_OPTION_LINEMODE_MODE_MODE_ACK

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Constant Field Values

TELNET_OPTION_LINEMODE_MODE_SOFT_TAB

public static final byte TELNET_OPTION_LINEMODE_MODE_SOFT_TAB

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Constant Field Values

TELNET_OPTION_LINEMODE_MODE_LIT_ECHO

public static final byte TELNET_OPTION_LINEMODE_MODE_LIT_ECHO

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Constant Field Values

TELNET_OPTION_LINEMODE_FORWARDMASK

public static final byte TELNET_OPTION_LINEMODE_FORWARDMASK

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Constant Field Values

TELNET_SE

public static final int TELNET_SE

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Constant Field Values

TELNET_NOP

public static final int TELNET_NOP

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Constant Field Values

TELNET_AYT

public static final int TELNET_AYT

Are you there: Send back to the NVT some visible evidence that the AYT was received.

See Also:

Constant Field Values

TELNET_EC

public static final int TELNET_EC

Erase character: The receiver should delete the last preceding undeleted character from the data stream.

See Also:

Constant Field Values

TELNET_GA

public static final int TELNET_GA

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Constant Field Values

TELNET_SB

public static final int TELNET_SB

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Constant Field Values

TELNET_WILL

public static final int TELNET_WILL

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Constant Field Values

TELNET_WONT

public static final int TELNET_WONT

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TELNET_DO

public static final int TELNET_DO

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TELNET_DONT

public static final int TELNET_DONT

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TELNET_IAC

public static final int TELNET_IAC

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Constant Field Values

TELNET_SEQUENCE_GOAHEAD

public static final byte[] TELNET_SEQUENCE_GOAHEAD

implementedOptions

public static final String implementedOptions

Byte array of telnet options we can and want to negociate about, all other commands will result in a DONT or WONT response.
Those implemented so far are:

• TELNET_OPTION_TOGGLEFLOWCONTROL
• TELNET_OPTION_LINEMODE
• TELNET_OPTION_WINDOWSIZE
• TELNET_OPTION_TERMINAL_TYPE
• TELNET_OPTION_ECHO

Method Detail

getConsoleDelegate

public ConsoleDelegate getConsoleDelegate()

getOutputFormat

public OutputFormat getOutputFormat()

start

public void start()
           throws TelnetServiceException

Start the session daemon: setup telnet options, then start the input processing.

Throws:

TelnetServiceException

stop

public void stop()

Stop this session

close

protected void close()

Close all connections

run

public void run()

Session run main loop

Specified by:

run in interface Runnable

writePrompt

protected void writePrompt()

write

protected void write(byte[] bbuf,
                     int off,
                     int len)

write

protected void write(char[] cbuf,
                     int off,
                     int len)

write

protected void write(String txt)

writeln

protected void writeln(String txt)

backspaceActiveText

public void backspaceActiveText(int count)

appendActiveText

protected void appendActiveText(char c)

appendActiveText

protected void appendActiveText(String txt,
                                int offsetUpdateMask)

replaceActiveText

protected void replaceActiveText(String txt,
                                 int offsetUpdateMask)

commitActiveText

protected void commitActiveText()

addSessionListener

public void addSessionListener(SessionListener listener)

removeAllSessionListeners

public void removeAllSessionListeners()

removeSessionListener

public void removeSessionListener(SessionListener listener)

notifyConnectionEstablished

public void notifyConnectionEstablished(SessionState sessionState)

notifyConnectionLost

public void notifyConnectionLost(SessionState sessionState)

getSessionState

public SessionState getSessionState()

getRemoteSocketAddress

public SocketAddress getRemoteSocketAddress()

getConnectionTimestamp

public Date getConnectionTimestamp()

output

public void output(SessionState sessionState,
                   Object subject)

Shortcut method for calling the session's OutputFormat to format the subject then calling the ConsoleDelegate to write the outcome to the console.

Parameters:

sessionState - the current session state

subject - the item to be output

Throws:

OutputFormatException