org.apache.sshd.common.channel

Interface Channel

All Superinterfaces:

AttributeRepository, AttributeStore, AutoCloseable, Channel, ChannelListenerManager, ChannelStreamWriterResolver, ChannelStreamWriterResolverManager, Closeable, PropertyResolver, SessionContextHolder, SessionHolder<Session>

All Known Subinterfaces:

ClientChannel, ServerChannel

All Known Implementing Classes:

AbstractClientChannel, AbstractServerChannel, AgentForwardedChannel, AgentForwardedChannel, ChannelAgentForwarding, ChannelAgentForwarding, ChannelDirectTcpip, ChannelExec, ChannelForwardedX11, ChannelSession, ChannelSession, ChannelShell, ChannelSubsystem, PtyCapableChannelSession, TcpipClientChannel, TcpipServerChannel

public interface Channel
extends SessionHolder<Session>, ChannelListenerManager, PropertyResolver, AttributeStore, ChannelStreamWriterResolverManager, Closeable

Represents a channel opened over an SSH session - holds information that is common both to server and client channels.

Author:

Apache MINA SSHD Project

Nested Class Summary

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

AttributeRepository.AttributeKey<T>

Field Summary

Fields

Modifier and Type	Field and Description
static String	CHANNEL_EXEC
static String	CHANNEL_SHELL
static String	CHANNEL_SUBSYSTEM

Fields inherited from interface org.apache.sshd.common.PropertyResolver

EMPTY

Fields inherited from interface org.apache.sshd.common.channel.throttle.ChannelStreamWriterResolver

NONE

Method Summary

Modifier and Type	Method and Description
void	addRequestHandler(RequestHandler<Channel> handler)
default void	addRequestHandlers(Collection<? extends RequestHandler<Channel>> handlers)
int	getId()
Window	getLocalWindow()
int	getRecipient()
Window	getRemoteWindow()
List<RequestHandler<Channel>>	getRequestHandlers()
void	handleChannelRegistrationResult(ConnectionService service, Session session, int id, boolean registered) Invoked after being successfully registered by the connection service - should throw a RuntimeException if not registered
void	handleChannelUnregistration(ConnectionService service) Called by the connection service to inform the channel that it has bee unregistered.
void	handleClose() Invoked when SSH_MSG_CHANNEL_CLOSE received
void	handleData(Buffer buffer) Invoked when SSH_MSG_CHANNEL_DATA received
void	handleEof() Invoked when SSH_MSG_CHANNEL_EOF received
void	handleExtendedData(Buffer buffer) Invoked when SSH_MSG_CHANNEL_EXTENDED_DATA received
void	handleFailure() Invoked when SSH_MSG_CHANNEL_FAILURE received
void	handleOpenFailure(Buffer buffer) For a client channel, this method will be called internally by the session when the server has rejected this channel opening.
void	handleOpenSuccess(int recipient, long rwSize, long packetSize, Buffer buffer) For a client channel, this method will be called internally by the session when the confirmation has been received.
void	handleRequest(Buffer buffer) Invoked when SSH_MSG_CHANNEL_REQUEST received
void	handleSuccess() Invoked when SSH_MSG_CHANNEL_SUCCESS received
void	handleWindowAdjust(Buffer buffer) Invoked when SSH_MSG_CHANNEL_WINDOW_ADJUST received
void	init(ConnectionService service, Session session, int id) Invoked when the local channel is initial created
boolean	isEofSignalled()
boolean	isInitialized()
OpenFuture	open(int recipient, long rwSize, long packetSize, Buffer buffer) For a server channel, this method will actually open the channel
void	removeRequestHandler(RequestHandler<Channel> handler)
default void	removeRequestHandlers(Collection<? extends RequestHandler<Channel>> handlers)
default <T> T	resolveAttribute(AttributeRepository.AttributeKey<T> key)
static <T> T	resolveAttribute(Channel channel, AttributeRepository.AttributeKey<T> key) Attempts to use the channel attribute, if not found then tries the session
IoWriteFuture	writePacket(Buffer buffer) Encode and send the given buffer.

Methods inherited from interface org.apache.sshd.common.session.SessionHolder

getSession, getSessionContext

Methods inherited from interface org.apache.sshd.common.channel.ChannelListenerManager

addChannelListener, getChannelListenerProxy, removeChannelListener

Methods inherited from interface org.apache.sshd.common.PropertyResolver

getBoolean, getBooleanProperty, getCharset, getInteger, getIntProperty, getLong, getLongProperty, getObject, getParentPropertyResolver, getProperties, getString, getStringProperty, isEmpty, isEmpty

Methods inherited from interface org.apache.sshd.common.AttributeStore

clearAttributes, computeAttributeIfAbsent, removeAttribute, setAttribute

Methods inherited from interface org.apache.sshd.common.AttributeRepository

attributeKeys, getAttribute, getAttributesCount, ofAttributesMap, ofKeyValuePair

Methods inherited from interface org.apache.sshd.common.channel.throttle.ChannelStreamWriterResolverManager

getChannelStreamWriterResolver, resolveChannelStreamWriter, resolveChannelStreamWriterResolver, setChannelStreamWriterResolver

Methods inherited from interface org.apache.sshd.common.Closeable

addCloseFutureListener, close, close, close, getMaxCloseWaitTime, isClosed, isClosing, isOpen, removeCloseFutureListener

Field Detail

CHANNEL_EXEC

static final String CHANNEL_EXEC

See Also:

Constant Field Values

CHANNEL_SHELL

static final String CHANNEL_SHELL

See Also:

Constant Field Values

CHANNEL_SUBSYSTEM

static final String CHANNEL_SUBSYSTEM

See Also:

Constant Field Values

Method Detail

getId

int getId()

Returns:

Local channel identifier

getRecipient

int getRecipient()

Returns:

Remote channel identifier

getLocalWindow

Window getLocalWindow()

getRemoteWindow

Window getRemoteWindow()

getRequestHandlers

List<RequestHandler<Channel>> getRequestHandlers()

addRequestHandler

void addRequestHandler(RequestHandler<Channel> handler)

addRequestHandlers

default void addRequestHandlers(Collection<? extends RequestHandler<Channel>> handlers)

removeRequestHandler

void removeRequestHandler(RequestHandler<Channel> handler)

removeRequestHandlers

default void removeRequestHandlers(Collection<? extends RequestHandler<Channel>> handlers)

handleClose

void handleClose()
          throws IOException

Invoked when SSH_MSG_CHANNEL_CLOSE received

Throws:

IOException - If failed to handle the message

handleWindowAdjust

void handleWindowAdjust(Buffer buffer)
                 throws IOException

Invoked when SSH_MSG_CHANNEL_WINDOW_ADJUST received

Parameters:

buffer - The rest of the message data Buffer after decoding the channel identifiers

Throws:

IOException - If failed to handle the message

handleRequest

void handleRequest(Buffer buffer)
            throws IOException

Invoked when SSH_MSG_CHANNEL_REQUEST received

Parameters:

buffer - The rest of the message data Buffer after decoding the channel identifiers

Throws:

IOException - If failed to handle the message

handleData

void handleData(Buffer buffer)
         throws IOException

Invoked when SSH_MSG_CHANNEL_DATA received

Parameters:

buffer - The rest of the message data Buffer after decoding the channel identifiers

Throws:

IOException - If failed to handle the message

handleExtendedData

void handleExtendedData(Buffer buffer)
                 throws IOException

Invoked when SSH_MSG_CHANNEL_EXTENDED_DATA received

Parameters:

buffer - The rest of the message data Buffer after decoding the channel identifiers

Throws:

IOException - If failed to handle the message

handleEof

void handleEof()
        throws IOException

Invoked when SSH_MSG_CHANNEL_EOF received

Throws:

IOException - If failed to handle the message

handleSuccess

void handleSuccess()
            throws IOException

Invoked when SSH_MSG_CHANNEL_SUCCESS received

Throws:

IOException - If failed to handle the message

handleFailure

void handleFailure()
            throws IOException

Invoked when SSH_MSG_CHANNEL_FAILURE received

Throws:

IOException - If failed to handle the message

init

void init(ConnectionService service,
          Session session,
          int id)
   throws IOException

Invoked when the local channel is initial created

Parameters:

service - The ConnectionService through which the channel is initialized

session - The Session associated with the channel

id - The locally assigned channel identifier

Throws:

IOException - If failed to process the initialization

handleChannelRegistrationResult

void handleChannelRegistrationResult(ConnectionService service,
                                     Session session,
                                     int id,
                                     boolean registered)

Invoked after being successfully registered by the connection service - should throw a RuntimeException if not registered

Parameters:

service - The ConnectionService through which the channel is registered

session - The Session associated with the channel

id - The locally assigned channel identifier

registered - Whether registration was successful or not

handleChannelUnregistration

void handleChannelUnregistration(ConnectionService service)

Called by the connection service to inform the channel that it has bee unregistered.

Parameters:

service - The ConnectionService through which the channel is unregistered

isInitialized

boolean isInitialized()

Returns:

true if call to init(ConnectionService, Session, int) was successfully completed

isEofSignalled

boolean isEofSignalled()

Returns:

true if the peer signaled that it will not send any more data

See Also:

RFC 4254 - section 5.3 - SSH_MSG_CHANNEL_EOF

open

OpenFuture open(int recipient,
                long rwSize,
                long packetSize,
                Buffer buffer)

For a server channel, this method will actually open the channel

Parameters:

recipient - Recipient identifier

rwSize - Read/Write window size (uint32)

packetSize - Preferred maximum packet size (uint32)

buffer - Incoming Buffer that triggered the call. Note: the buffer's read position is exactly after the information that read to this call was decoded

Returns:

An OpenFuture for the channel open request

handleOpenSuccess

void handleOpenSuccess(int recipient,
                       long rwSize,
                       long packetSize,
                       Buffer buffer)
                throws IOException

For a client channel, this method will be called internally by the session when the confirmation has been received.

Parameters:

recipient - Recipient identifier

rwSize - Read/Write window size (uint32)

packetSize - Preferred maximum packet size (uint32)

buffer - Incoming Buffer that triggered the call. Note: the buffer's read position is exactly after the information that read to this call was decoded

Throws:

IOException - If failed to handle the success

handleOpenFailure

void handleOpenFailure(Buffer buffer)
                throws IOException

For a client channel, this method will be called internally by the session when the server has rejected this channel opening.

Parameters:

buffer - Incoming Buffer that triggered the call. Note: the buffer's read position is exactly after the information that read to this call was decoded

Throws:

IOException - If failed to handle the success

resolveAttribute

default <T> T resolveAttribute(AttributeRepository.AttributeKey<T> key)

Specified by:

resolveAttribute in interface AttributeRepository

resolveAttribute

static <T> T resolveAttribute(Channel channel,
                              AttributeRepository.AttributeKey<T> key)

Attempts to use the channel attribute, if not found then tries the session

Type Parameters:

T - The generic attribute type

Parameters:

channel - The Channel - ignored if null

key - The attribute key - never null

Returns:

Associated value - null if not found

See Also:

SessionHolder.getSession(), Session.resolveAttribute(Session, AttributeRepository.AttributeKey)

writePacket

IoWriteFuture writePacket(Buffer buffer)
                   throws IOException

Encode and send the given buffer. Note: for session packets 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.

Parameters:

buffer - the buffer to encode and send. NOTE: the buffer must not be touched until the returned write future is completed.

Returns:

An IoWriteFuture that can be used to check when the packet has actually been sent

Throws:

IOException - if an error occurred when encoding or sending the packet