com.Prominic.jFTPd
Class PassiveConnection

java.lang.Object
  java.lang.Thread
      com.Prominic.jFTPd.PassiveConnection

All Implemented Interfaces:

java.lang.Runnable

public class PassiveConnection
extends java.lang.Thread

This thread takes care of opening a passive connection when the FTP client requests this using the PASV command. jFTPd needs to open a local socket which will be reported to the client, and the client needs to be informed about the new data socket as a response to the PASV command.
It knows to only open a socket using a predefined range of ports (for firewall friendly behaviour - when you can open tunnels from the firewall back to jFTPd on the specified range of ports).
By default, it waits for 60 seconds for the client to connect back, otherwise it will drop the socket and notify the client (timeouts always happen due to a misconfigured firewall - mostly on the server side )

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

java.lang.Thread.State, java.lang.Thread.UncaughtExceptionHandler

Field Summary

(package private) boolean	DEBUG
(package private) static int	highPort
(package private) static int	lowPort
(package private) static int	maxTries
(package private) static int	nextPort
(package private) int	port
(package private) static boolean[]	portsUsed
(package private) java.net.Socket	sock
(package private) java.net.ServerSocket	ss
(package private) int	stage
(package private) static int	timeout

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

PassiveConnection()
Creates a passive connection.

Method Summary

int	getPort() Gets the port chosen by the passive connection (to report it back to the user)
java.net.Socket	getSocket() Gets the socket opened by the passive connection (to use it to exchange data with the client).
int	getStage() Gets the stage of the passive connection.
static int	getTimeout() Gets the timeout value.
void	run() Starts the passive connection which awaits a connection from the client for the specified timeout.
static void	setPortRange(int low, int high) This sets the ports range from which the PassiveConnection can select ports.
static void	setTimeout(int newTimeout) Sets new timeout value for which the PassiveConnection will wait for a connection from the client.
protected void	setupListener() This method will try to find an empty port (either guessing or picking one from the range of allowed ports).
void	terminate() Terminates the passive connection and closes the sockets.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG

final boolean DEBUG

See Also:

Constant Field Values

sock

java.net.Socket sock

port

int port

ss

java.net.ServerSocket ss

stage

int stage

lowPort

static int lowPort

highPort

static int highPort

portsUsed

static boolean[] portsUsed

nextPort

static int nextPort

maxTries

static final int maxTries

See Also:

Constant Field Values

timeout

static int timeout

Constructor Detail

PassiveConnection

public PassiveConnection()

Creates a passive connection. Creation date: (10/17/2001 6:01:27 PM)

Method Detail

getPort

public int getPort()

Gets the port chosen by the passive connection (to report it back to the user)

Returns:

int chosen port.

getSocket

public java.net.Socket getSocket()

Gets the socket opened by the passive connection (to use it to exchange data with the client).

Returns:

Socket passive socket.

getStage

public int getStage()

Gets the stage of the passive connection. Stages are:
0 - not (or finished) running, not listening
1 - running, listening
2 - running, finished listening

Returns:

int stage.

getTimeout

public static int getTimeout()

Gets the timeout value.

Returns:

int the time out value.

run

public void run()

Starts the passive connection which awaits a connection from the client for the specified timeout. It closes the server socket it opens once a socket has been obtained from the client. Creation date: (10/17/2001 6:01:27 PM)

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class java.lang.Thread

setPortRange

public static void setPortRange(int low,
                                int high)

This sets the ports range from which the PassiveConnection can select ports. Usefull for firewalls when you need to create a bunch of tunnels from the firewall range of ports to jFTPd.
Assuming this only gets called once before any objects are constructed.

Parameters:

low - - low index

high - - high index.

setTimeout

public static void setTimeout(int newTimeout)

Sets new timeout value for which the PassiveConnection will wait for a connection from the client. Needed as due to firewalls, client cannot reach the server on the advertised address and port.

setupListener

protected void setupListener()

This method will try to find an empty port (either guessing or picking one from the range of allowed ports). Care must be used to make sure there are more ports available, in the range than connections available, otherwise this will loop through all the ports for maxtries value (10) before giving up.

terminate

public void terminate()

Terminates the passive connection and closes the sockets.