org.apache.sshd.common.session
Class AbstractSession

java.lang.Object
  org.apache.sshd.common.session.AbstractSession

All Implemented Interfaces:

Session

Direct Known Subclasses:

ClientSessionImpl, ServerSession

public abstract class AbstractSession
extends java.lang.Object
implements Session

The AbstractSession handles all the basic SSH protocol such as key exchange, authentication, encoding and decoding. Both server side and client side sessions should inherit from this abstract class. Some basic packet processing methods are defined but the actual call to these methods should be done from the handleMessage(org.apache.sshd.common.util.Buffer) method, which is dependant on the state and side of this session. TODO: if there is any very big packet, decoderBuffer and uncompressBuffer will get quite big and they won't be resized down at any time. Though the packet size is really limited by the channel max packet size

Author:

Apache MINA SSHD Project

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.sshd.common.Session

Session.AttributeKey<T>

Field Summary

protected java.util.Map<Session.AttributeKey<?>,java.lang.Object>	attributes
protected boolean	authed Boolean indicating if this session has been authenticated or not
protected java.util.Map<java.lang.Integer,Channel>	channels Map of channels keyed by the identifier
protected java.lang.String[]	clientProposal
protected java.lang.String	clientVersion
protected CloseFuture	closeFuture A future that will be set 'closed' when the connection is closed.
protected boolean	closing The session is being closed
protected java.lang.Object	decodeLock
protected Buffer	decoderBuffer
protected int	decoderLength
protected int	decoderState
protected java.lang.Object	encodeLock
protected FactoryManager	factoryManager The factory manager used to retrieve factories of Ciphers, Macs and other objects
protected byte[]	I_C
protected byte[]	I_S
protected Cipher	inCipher
protected int	inCipherSize
protected Compression	inCompression
protected Mac	inMac
protected byte[]	inMacResult
protected org.apache.mina.core.session.IoSession	ioSession The underlying MINA session
protected KeyExchange	kex
protected java.lang.Object	lock Lock object for this session state
protected org.slf4j.Logger	log Our logger
protected java.lang.String[]	negociated
protected int	nextChannelId Next channel identifier
protected Cipher	outCipher
protected int	outCipherSize
protected Compression	outCompression
protected Mac	outMac
protected Random	random The pseudo random generator
protected long	seqi
protected long	seqo
protected java.lang.String[]	serverProposal
protected java.lang.String	serverVersion
static java.lang.String	SESSION Name of the property where this session is stored in the attributes of the underlying MINA session.
protected byte[]	sessionId
protected Buffer	uncompressBuffer

Constructor Summary

AbstractSession(FactoryManager factoryManager, org.apache.mina.core.session.IoSession ioSession)
Create a new session.

Method Summary

static void	attachSession(org.apache.mina.core.session.IoSession ioSession, AbstractSession session) Attach a session to the MINA session
protected void	channelClose(Buffer buffer) Close a channel due to a close packet received
protected void	channelData(Buffer buffer) Process incoming data on a channel
protected void	channelEof(Buffer buffer) Process end of file on a channel
protected void	channelExtendedData(Buffer buffer) Process incoming extended data on a channel
protected void	channelFailure(Buffer buffer) Process a failure on a channel
protected void	channelOpenConfirmation(Buffer buffer)
protected void	channelOpenFailure(Buffer buffer)
protected void	channelRequest(Buffer buffer) Service a request on a channel
protected void	channelWindowAdjust(Buffer buffer) Process a window adjust packet on a channel
CloseFuture	close(boolean immediately) Close this session.
Buffer	createBuffer(SshConstants.Message cmd, int len) Create a new buffer for the specified SSH packet and reserve the needed space (5 bytes) for the packet header.
protected java.lang.String[]	createProposal(java.lang.String hostKeyTypes) Create our proposal for SSH negociation
protected void	decode() Decode the incoming buffer and handle packets as needed.
void	disconnect(int reason, java.lang.String msg) Send a disconnect packet with the given reason and message.
protected java.lang.String	doReadIdentification(Buffer buffer) Read the remote identification from this buffer.
void	exceptionCaught(java.lang.Throwable t) Handle any exceptions that occured on this session.
<T> T	getAttribute(Session.AttributeKey<T> key) Returns the value of the user-defined attribute of this session.
protected Channel	getChannel(Buffer buffer) Retrieve the channel designated by the given packet
FactoryManager	getFactoryManager() Retrieve the factory manager
int	getIntProperty(java.lang.String name, int defaultValue) Retrieve a configuration property as an integer
org.apache.mina.core.session.IoSession	getIoSession() Retrieve the mina session
protected int	getNextChannelId()
static AbstractSession	getSession(org.apache.mina.core.session.IoSession ioSession) Retrieve the session from the MINA session.
static AbstractSession	getSession(org.apache.mina.core.session.IoSession ioSession, boolean allowNull) Retrieve the session from the MINA session.
protected abstract void	handleMessage(Buffer buffer) Abstract method for processing incoming decoded packets.
void	messageReceived(org.apache.mina.core.buffer.IoBuffer buffer) Main input point for the MINA framework.
protected void	negociate() Compute the negociated proposals by merging the client and server proposal.
protected void	notImplemented() Send an unimplemented packet.
protected abstract boolean	readIdentification(Buffer buffer) Read the other side identification.
protected byte[]	receiveKexInit(Buffer buffer, java.lang.String[] proposal) Receive the remote key exchange init message.
protected void	receiveNewKeys(boolean isServer) Put new keys into use.
int	registerChannel(Channel channel) Register a newly created channel with a new unique identifier
protected void	sendIdentification(java.lang.String ident) Send our identification.
protected byte[]	sendKexInit(java.lang.String[] proposal) Send the key exchange initialization packet.
protected void	sendNewKeys() Send a message to put new keys into use.
<T,E extends T> T	setAttribute(Session.AttributeKey<T> key, E value) Sets a user-defined attribute.
void	unregisterChannel(Channel channel) Remove this channel from the list of managed channels
org.apache.mina.core.future.WriteFuture	writePacket(Buffer buffer) Encode and send the given buffer.

Methods inherited from class java.lang.Object

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

Field Detail

SESSION

public static final java.lang.String SESSION

Name of the property where this session is stored in the attributes of the underlying MINA session. See getSession(IoSession, boolean) and attachSession(IoSession, AbstractSession).

See Also:

Constant Field Values

log

protected final org.slf4j.Logger log

Our logger

factoryManager

protected final FactoryManager factoryManager

The factory manager used to retrieve factories of Ciphers, Macs and other objects

ioSession

protected final org.apache.mina.core.session.IoSession ioSession

The underlying MINA session

random

protected final Random random

The pseudo random generator

lock

protected final java.lang.Object lock

Lock object for this session state

closeFuture

protected final CloseFuture closeFuture

A future that will be set 'closed' when the connection is closed.

closing

protected volatile boolean closing

The session is being closed

authed

protected boolean authed

Boolean indicating if this session has been authenticated or not

channels

protected final java.util.Map<java.lang.Integer,Channel> channels

Map of channels keyed by the identifier

nextChannelId

protected int nextChannelId

Next channel identifier

sessionId

protected byte[] sessionId

serverVersion

protected java.lang.String serverVersion

clientVersion

protected java.lang.String clientVersion

serverProposal

protected java.lang.String[] serverProposal

clientProposal

protected java.lang.String[] clientProposal

negociated

protected java.lang.String[] negociated

I_C

protected byte[] I_C

I_S

protected byte[] I_S

kex

protected KeyExchange kex

outCipher

protected Cipher outCipher

inCipher

protected Cipher inCipher

outCipherSize

protected int outCipherSize

inCipherSize

protected int inCipherSize

outMac

protected Mac outMac

inMac

protected Mac inMac

inMacResult

protected byte[] inMacResult

outCompression

protected Compression outCompression

inCompression

protected Compression inCompression

seqi

protected long seqi

seqo

protected long seqo

decoderBuffer

protected Buffer decoderBuffer

uncompressBuffer

protected Buffer uncompressBuffer

decoderState

protected int decoderState

decoderLength

protected int decoderLength

encodeLock

protected final java.lang.Object encodeLock

decodeLock

protected final java.lang.Object decodeLock

attributes

protected final java.util.Map<Session.AttributeKey<?>,java.lang.Object> attributes

Constructor Detail

AbstractSession

public AbstractSession(FactoryManager factoryManager,
                       org.apache.mina.core.session.IoSession ioSession)

Create a new session.

Parameters:

factoryManager - the factory manager

ioSession - the underlying MINA session

Method Detail

getSession

public static final AbstractSession getSession(org.apache.mina.core.session.IoSession ioSession)

Retrieve the session from the MINA session. If the session has not been attached, an IllegalStateException will be thrown

Parameters:

ioSession - the MINA session

Returns:

the session attached to the MINA session

getSession

public static final AbstractSession getSession(org.apache.mina.core.session.IoSession ioSession,
                                               boolean allowNull)

Retrieve the session from the MINA session. If the session has not been attached and allowNull is false, an IllegalStateException will be thrown, else a null will be returned

Parameters:

ioSession - the MINA session

allowNull - if true, a null value may be returned if no session is attached

Returns:

the session attached to the MINA session or null

attachSession

public static final void attachSession(org.apache.mina.core.session.IoSession ioSession,
                                       AbstractSession session)

Attach a session to the MINA session

Parameters:

ioSession - the MINA session

session - the session to attach

getIoSession

public org.apache.mina.core.session.IoSession getIoSession()

Retrieve the mina session

Returns:

the mina session

getFactoryManager

public FactoryManager getFactoryManager()

Retrieve the factory manager

Specified by:

getFactoryManager in interface Session

Returns:

the factory manager for this session

messageReceived

public void messageReceived(org.apache.mina.core.buffer.IoBuffer buffer)
                     throws java.lang.Exception

Main input point for the MINA framework. This method will be called each time new data is received on the socket and will append it to the input buffer before calling the decode() method.

Parameters:

buffer - the new buffer received

Throws:

java.lang.Exception - if an error occurs while decoding or handling the data

handleMessage

protected abstract void handleMessage(Buffer buffer)
                               throws java.lang.Exception

Abstract method for processing incoming decoded packets. The given buffer will hold the decoded packet, starting from the command byte at the read position. Packets must be processed within this call or be copied because the given buffer is meant to be changed and updated when this method returns.

Parameters:

buffer - the buffer containing the packet

Throws:

java.lang.Exception - if an exeption occurs while handling this packet.

exceptionCaught

public void exceptionCaught(java.lang.Throwable t)

Handle any exceptions that occured on this session. The session will be closed and a disconnect packet will be sent before if the given exception is an SshException.

Specified by:

exceptionCaught in interface Session

Parameters:

t - the exception to process

Throws:

java.io.IOException

close

public CloseFuture close(boolean immediately)

Close this session. This method will close all channels, then close the underlying MINA session. The call will not block until the mina session is actually closed.

writePacket

public org.apache.mina.core.future.WriteFuture writePacket(Buffer buffer)
                                                    throws java.io.IOException

Encode and send the given buffer. The buffer has to have 5 bytes free at the beginning to allow the encoding to take place. Also, the write position of the buffer has to be set to the position of the last byte to write.

Specified by:

writePacket in interface Session

Parameters:

buffer - the buffer to encode and send

Returns:

a future that can be used to check when the packet has actually been sent

Throws:

java.io.IOException - if an error occured when encoding sending the packet

createBuffer

public Buffer createBuffer(SshConstants.Message cmd,
                           int len)

Create a new buffer for the specified SSH packet and reserve the needed space (5 bytes) for the packet header.

Specified by:

createBuffer in interface Session

Parameters:

cmd - the SSH command

len - estimated number of bytes the buffer will hold, 0 if unknown.

Returns:

a new buffer ready for write

decode

protected void decode()
               throws java.lang.Exception

Decode the incoming buffer and handle packets as needed.

Throws:

java.lang.Exception

sendIdentification

protected void sendIdentification(java.lang.String ident)

Send our identification.

Parameters:

ident - our identification to send

readIdentification

protected abstract boolean readIdentification(Buffer buffer)
                                       throws java.io.IOException

Read the other side identification. This method is specific to the client or server side, but both should call doReadIdentification(org.apache.sshd.common.util.Buffer) and store the result in the needed property.

Parameters:

buffer - the buffer containing the remote identification

Returns:

true if the identification has been fully read or false if more data is needed

Throws:

java.io.IOException - if an error occurs such as a bad protocol version

doReadIdentification

protected java.lang.String doReadIdentification(Buffer buffer)

Read the remote identification from this buffer. If more data is needed, the buffer will be reset to its original state and a null value will be returned. Else the identification string will be returned and the data read will be consumed from the buffer.

Parameters:

buffer - the buffer containing the identification string

Returns:

the remote identification or null if more data is needed

createProposal

protected java.lang.String[] createProposal(java.lang.String hostKeyTypes)

Create our proposal for SSH negociation

Parameters:

hostKeyTypes - the list of supported host key types

Returns:

an array of 10 strings holding this proposal

sendKexInit

protected byte[] sendKexInit(java.lang.String[] proposal)
                      throws java.io.IOException

Send the key exchange initialization packet. This packet contains random data along with our proposal.

Parameters:

proposal - our proposal for key exchange negociation

Returns:

the sent packet which must be kept for later use

Throws:

java.io.IOException - if an error occured sending the packet

receiveKexInit

protected byte[] receiveKexInit(Buffer buffer,
                                java.lang.String[] proposal)

Receive the remote key exchange init message. The packet data is returned for later use.

Parameters:

buffer - the buffer containing the key exchange init packet

proposal - the remote proposal to fill

Returns:

the packet data

sendNewKeys

protected void sendNewKeys()
                    throws java.io.IOException

Send a message to put new keys into use.

Throws:

java.io.IOException - if an error occurs sending the message

receiveNewKeys

protected void receiveNewKeys(boolean isServer)
                       throws java.lang.Exception

Put new keys into use. This method will intialize the ciphers, digests, macs and compression according to the negociated server and client proposals.

Parameters:

isServer - boolean indicating if this session is on the server or the client side

Throws:

java.lang.Exception - if an error occurs

disconnect

public void disconnect(int reason,
                       java.lang.String msg)
                throws java.io.IOException

Send a disconnect packet with the given reason and message. Once the packet has been sent, the session will be closed asynchronously.

Parameters:

reason - the reason code for this disconnect

msg - the text message

Throws:

java.io.IOException - if an error occured sending the packet

notImplemented

protected void notImplemented()
                       throws java.io.IOException

Send an unimplemented packet. This packet should contain the sequence id of the usupported packet: this number is assumed to be the last packet received.

Throws:

java.io.IOException - if an error occured sending the packet

negociate

protected void negociate()

Compute the negociated proposals by merging the client and server proposal. The negocatiated proposal will be stored in the negociated property.

getNextChannelId

protected int getNextChannelId()

registerChannel

public int registerChannel(Channel channel)
                    throws java.lang.Exception

Description copied from interface: Session

Register a newly created channel with a new unique identifier

Specified by:

registerChannel in interface Session

Parameters:

channel - the channel to register

Returns:

the id of this channel

Throws:

java.lang.Exception

channelOpenConfirmation

protected void channelOpenConfirmation(Buffer buffer)
                                throws java.io.IOException

Throws:

java.io.IOException

channelOpenFailure

protected void channelOpenFailure(Buffer buffer)
                           throws java.io.IOException

Throws:

java.io.IOException

channelData

protected void channelData(Buffer buffer)
                    throws java.lang.Exception

Process incoming data on a channel

Parameters:

buffer - the buffer containing the data

Throws:

java.lang.Exception - if an error occurs

channelExtendedData

protected void channelExtendedData(Buffer buffer)
                            throws java.lang.Exception

Process incoming extended data on a channel

Parameters:

buffer - the buffer containing the data

Throws:

java.lang.Exception - if an error occurs

channelWindowAdjust

protected void channelWindowAdjust(Buffer buffer)
                            throws java.lang.Exception

Process a window adjust packet on a channel

Parameters:

buffer - the buffer containing the window adjustement parameters

Throws:

java.lang.Exception - if an error occurs

channelEof

protected void channelEof(Buffer buffer)
                   throws java.lang.Exception

Process end of file on a channel

Parameters:

buffer - the buffer containing the packet

Throws:

java.lang.Exception - if an error occurs

channelClose

protected void channelClose(Buffer buffer)
                     throws java.lang.Exception

Close a channel due to a close packet received

Parameters:

buffer - the buffer containing the packet

Throws:

java.lang.Exception - if an error occurs

unregisterChannel

public void unregisterChannel(Channel channel)

Remove this channel from the list of managed channels

Specified by:

unregisterChannel in interface Session

Parameters:

channel - the channel

channelRequest

protected void channelRequest(Buffer buffer)
                       throws java.io.IOException

Service a request on a channel

Parameters:

buffer - the buffer containing the request

Throws:

java.lang.Exception - if an error occurs

java.io.IOException

channelFailure

protected void channelFailure(Buffer buffer)
                       throws java.lang.Exception

Process a failure on a channel

Parameters:

buffer - the buffer containing the packet

Throws:

java.lang.Exception - if an error occurs

getChannel

protected Channel getChannel(Buffer buffer)
                      throws java.io.IOException

Retrieve the channel designated by the given packet

Parameters:

buffer - the incoming packet

Returns:

the target channel

Throws:

java.io.IOException - if the channel does not exists

getIntProperty

public int getIntProperty(java.lang.String name,
                          int defaultValue)

Retrieve a configuration property as an integer

Specified by:

getIntProperty in interface Session

Parameters:

name - the name of the property

defaultValue - the default value

Returns:

the value of the configuration property or the default value if not found

getAttribute

public <T> T getAttribute(Session.AttributeKey<T> key)

Returns the value of the user-defined attribute of this session.

Specified by:

getAttribute in interface Session

Parameters:

key - the key of the attribute; must not be null.

Returns:

null if there is no attribute with the specified key

setAttribute

public <T,E extends T> T setAttribute(Session.AttributeKey<T> key,
                                      E value)

Sets a user-defined attribute.

Specified by:

setAttribute in interface Session

Parameters:

key - the key of the attribute; must not be null.

value - the value of the attribute; must not be null.

Returns:

The old value of the attribute. null if it is new.