com.tailf.jnc

Class SSHSession

java.lang.Object

com.tailf.jnc.SSHSession

All Implemented Interfaces:

Transport

public class SSHSession
extends java.lang.Object
implements Transport

A SSH NETCONF transport. Can be used whenever NetconfSession intends to use SSH for its transport. This class uses the Ganymed SSH implementation. (http://www.ganymed .ethz.ch/ssh2/)

Example:

 SSHConnection c = new SSHConnection("127.0.0.1", 789);
 c.authenticateWithPassword("ola", "secret");
 SSHSession ssh = new SSHSession(c);
 NetconfSession dev1 = new NetconfSession(ssh);
 

Field Summary

Fields

Modifier and Type	Field and Description
protected long	readTimeout

Constructor Summary

Constructors

Constructor and Description
SSHSession(SSHConnection con) Constructor for SSH session object.
SSHSession(SSHConnection con, long readTimeout) Constructor with an extra argument for a readTimeout timer.

Method Summary

Modifier and Type	Method and Description
void	addSubscriber(IOSubscriber s) Add an IO Subscriber for this transport.
void	close() Closes the SSH channnel
void	delSubscriber(IOSubscriber s) Removes an IO subscriber.
void	flush() Signals that the final chunk of data has be printed to the output transport stream.
long	getReadTimeout() Return the readTimeout value that is used to read data from the ssh socket.
Session	getSession() Needed by users that need to monitor a session for EOF .
SSHConnection	getSSHConnection() Return the underlying ssh connection object
void	print(int iVal) Prints an integer (as text) to the output stream.
void	print(java.lang.String s) Prints text to the output stream.
void	println(int iVal) Prints an integer (as text) to the output stream.
void	println(java.lang.String s) Print text to the output stream.
java.lang.StringBuffer	readOne() Reads in "one" reply from the SSH transport input stream.
int	readUntilWouldBlock() If we have readTimeout set, and an outstanding operation was timed out - the socket may still be alive.
boolean	ready() Tell whether this transport is ready to be read.
boolean	serverSideClosed() given a live SSHSession, check if the server side has closed it's end of the ssh socket
void	setReadTimeout(int readTimeout) Set the read timeout

Methods inherited from class java.lang.Object

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

Field Detail

readTimeout

protected long readTimeout

Constructor Detail

SSHSession

public SSHSession(SSHConnection con)
           throws java.io.IOException,
                  JNCException

Constructor for SSH session object. This method creates a a new SSh channel on top of an existing connection. SSHSession objects imlement the Transport interface and they are passed into the constructor of the NetconfSession class.

Parameters:

con - an established and authenticated SSH connection

Throws:

java.io.IOException

JNCException

SSHSession

public SSHSession(SSHConnection con,
                  long readTimeout)
           throws java.io.IOException,
                  JNCException

Constructor with an extra argument for a readTimeout timer.

Parameters:

con -

readTimeout - Time to wait for read. (in milliseconds)

Throws:

java.io.IOException

JNCException

Method Detail

getSSHConnection

public SSHConnection getSSHConnection()

Return the underlying ssh connection object

getReadTimeout

public long getReadTimeout()

Return the readTimeout value that is used to read data from the ssh socket. If a read doesn't complete within the stipulated timeout an INMException is thrown *

setReadTimeout

public void setReadTimeout(int readTimeout)

Set the read timeout

Parameters:

readTimeout - timout in milliseconds The readTimeout parameter affects all read operations. If a timeout is reached, an INMException is thrown. The socket is not closed.

ready

public boolean ready()
              throws java.io.IOException

Tell whether this transport is ready to be read.

Specified by:

ready in interface Transport

Returns:

true if there is something to read, false otherwise. This function can typically be used to poll a socket and see there is data to be read. The function will also return true if the server side has closed its end of the ssh socket. To explictly just check for that, use the serverSideClosed() method.

Throws:

java.io.IOException

serverSideClosed

public boolean serverSideClosed()
                         throws java.io.IOException

given a live SSHSession, check if the server side has closed it's end of the ssh socket

Throws:

java.io.IOException

readUntilWouldBlock

public int readUntilWouldBlock()

If we have readTimeout set, and an outstanding operation was timed out - the socket may still be alive. However since we timed out our read operation and subsequently didn't process the xml data - there may be parts of unprocessed xml data left on the socket. This function reads and throws away all such unprocessed data. An alternative after timeout is of course to close the socket and reconnect.

Returns:

number of discarded characters

readOne

public java.lang.StringBuffer readOne()
                               throws java.io.IOException,
                                      JNCException

Reads in "one" reply from the SSH transport input stream. A ]]>]]> character sequence is used to separate multiple replies as described in RFC 4742.

Specified by:

readOne in interface Transport

Throws:

java.io.IOException

JNCException

print

public void print(int iVal)

Prints an integer (as text) to the output stream.

Specified by:

print in interface Transport

Parameters:

iVal - Text to send to the stream.

print

public void print(java.lang.String s)

Prints text to the output stream.

Specified by:

print in interface Transport

Parameters:

s - Text to send to the stream.

println

public void println(int iVal)

Prints an integer (as text) to the output stream. A newline char is appended to end of the output stream.

Specified by:

println in interface Transport

Parameters:

iVal - Text to send to the stream.

println

public void println(java.lang.String s)

Print text to the output stream. A newline char is appended to end of the output stream.

Specified by:

println in interface Transport

Parameters:

s - Text to send to the stream.

addSubscriber

public void addSubscriber(IOSubscriber s)

Add an IO Subscriber for this transport. This is useful for tracing the messages.

Parameters:

s - An IOSUbscriber that will be called whenever there is something received or sent on this transport.

delSubscriber

public void delSubscriber(IOSubscriber s)

Removes an IO subscriber.

Parameters:

s - The IO subscriber to remove.

flush

public void flush()

Signals that the final chunk of data has be printed to the output transport stream. This method furthermore flushes the transport output stream buffer.

A ]]>]]> character sequence is added, as described in RFC 4742, to signal that the last part of the reply has been sent.

Specified by:

flush in interface Transport

getSession

public Session getSession()

Needed by users that need to monitor a session for EOF . This will return the underlying Ganymed SSH Session object. The ganymed Session object has a method waitForCondition() that can be used to check the connection state of an ssh soscket. Assuming a A Session object s:

 int conditionSet =
     ChannelCondition.TIMEOUT ;amp
     ChannelCondition.CLOSED ;amp
     ChannelCondition.EOF;
     conditionSet = s.waitForCondition(conditionSet, 1);
  if (conditionSet != ChannelCondition.TIMEOUT) {
      // We know the server closed it's end of the ssh
      // socket
 

close

public void close()

Closes the SSH channnel

Specified by:

close in interface Transport