class documentation

An implementation of the 'ssh-connection' service. It is used to multiplex multiple channels over the single SSH connection.

Method __init__ Undocumented
Method adjustWindow Tell the other side that we will receive more data. This should not normally need to be called as it is managed automatically.
Method channelClosed Called when a channel is closed. It clears the local state related to the channel, and calls channel.closed(). MAKE SURE YOU CALL THIS METHOD, even if you subclass SSHConnection. If you don't, things will break mysteriously.
Method getChannel The other side requested a channel of some sort. channelType is the type of channel being requested, windowSize is the initial size of the remote window, maxPacket is the largest packet we should send, data is any other packet data (often nothing).
Method gotGlobalRequest We got a global request. pretty much, this is just used by the client to request that we forward a port from the server to the client. Returns either:
Method openChannel Open a new channel on this connection.
Method sendClose Close a channel.
Method sendData Send data to a channel. This should not normally be used: instead use channel.write(data) as it manages the window automatically.
Method sendEOF Send an EOF (End of File) for a channel.
Method sendExtendedData Send extended data to a channel. This should not normally be used: instead use channel.writeExtendedData(data, dataType) as it manages the window automatically.
Method sendGlobalRequest Send a global request for this connection. Current this is only used for remote->local TCP forwarding.
Method sendRequest Send a request to a channel.
Method serviceStarted called when the service is active on the transport.
Method serviceStopped Called when the connection is stopped.
Method ssh_CHANNEL_CLOSE The other side is closing its end; it does not want to receive any more data. Payload:
Method ssh_CHANNEL_DATA The other side is sending us data. Payload:
Method ssh_CHANNEL_EOF The other side is not sending any more data. Payload:
Method ssh_CHANNEL_EXTENDED_DATA The other side is sending us exteneded data. Payload:
Method ssh_CHANNEL_FAILURE Our channel request to the other side failed. Payload:
Method ssh_CHANNEL_OPEN The other side wants to get a channel. Payload:
Method ssh_CHANNEL_OPEN_CONFIRMATION The other side accepted our MSG_CHANNEL_OPEN request. Payload:
Method ssh_CHANNEL_OPEN_FAILURE The other side did not accept our MSG_CHANNEL_OPEN request. Payload:
Method ssh_CHANNEL_REQUEST The other side is sending a request to a channel. Payload:
Method ssh_CHANNEL_SUCCESS Our channel request to the other side succeeded. Payload:
Method ssh_CHANNEL_WINDOW_ADJUST The other side is adding bytes to its window. Payload:
Method ssh_GLOBAL_REQUEST The other side has made a global request. Payload:
Method ssh_REQUEST_FAILURE Our global request failed. Get the appropriate Deferred and errback it with the packet we received.
Method ssh_REQUEST_SUCCESS Our global request succeeded. Get the appropriate Deferred and call it back with the packet we received.
Class Variable name Undocumented
Instance Variable channels a dict mapping a local channel ID to SSHChannel subclasses.
Instance Variable channelsToRemoteChannel a dict mapping a SSHChannel subclass to remote channel ID.
Instance Variable deferreds a dict mapping a local channel ID to a list of Deferreds for outstanding channel requests. Also, the 'global' key stores the list of pending global request Deferreds.
Instance Variable localChannelID the next number to use as a local channel ID.
Instance Variable localToRemoteChannel a dict mapping a local channel ID to a remote channel ID.
Instance Variable transport Undocumented
Method _cbChannelRequest Called back if the other side wanted a reply to a channel request. If the result is true, send a MSG_CHANNEL_SUCCESS. Otherwise, raise a error.ConchError
Method _cleanupGlobalDeferreds All pending requests that have returned a deferred must be errbacked when this service is stopped, otherwise they might be left uncalled and uncallable.
Method _ebChannelRequest Called if the other wisde wanted a reply to the channel requeset and the channel request failed.
Class Variable _log Undocumented

Inherited from SSHService:

Method logPrefix Undocumented
Method packetReceived called when we receive a packet on the transport
Class Variable protocolMessages Undocumented
def __init__(self): (source)

Undocumented

def adjustWindow(self, channel, bytesToAdd): (source)

Tell the other side that we will receive more data. This should not normally need to be called as it is managed automatically.

Parameters
channel:subclass of SSHChannelUndocumented
bytesToAdd:intUndocumented
def channelClosed(self, channel): (source)

Called when a channel is closed. It clears the local state related to the channel, and calls channel.closed(). MAKE SURE YOU CALL THIS METHOD, even if you subclass SSHConnection. If you don't, things will break mysteriously.

Parameters
channel:SSHChannelUndocumented
def getChannel(self, channelType, windowSize, maxPacket, data): (source)

The other side requested a channel of some sort. channelType is the type of channel being requested, windowSize is the initial size of the remote window, maxPacket is the largest packet we should send, data is any other packet data (often nothing).

We return a subclass of SSHChannel.

By default, this dispatches to a method 'channel_channelType' with any non-alphanumerics in the channelType replace with _'s. If it cannot find a suitable method, it returns an OPEN_UNKNOWN_CHANNEL_TYPE error. The method is called with arguments of windowSize, maxPacket, data.

Parameters
channelType:bytesUndocumented
windowSize:intUndocumented
maxPacket:intUndocumented
data:bytesUndocumented
Returns
subclass of SSHChannel/tupleUndocumented
def gotGlobalRequest(self, requestType, data): (source)

We got a global request. pretty much, this is just used by the client to request that we forward a port from the server to the client. Returns either:

  • 1: request accepted
  • 1, <data>: request accepted with request specific data
  • 0: request denied

By default, this dispatches to a method 'global_requestType' with -'s in requestType replaced with _'s. The found method is passed data. If this method cannot be found, this method returns 0. Otherwise, it returns the return value of that method.

Parameters
requestType:bytesUndocumented
data:bytesUndocumented
Returns
int/tupleUndocumented
def openChannel(self, channel, extra=b''): (source)

Open a new channel on this connection.

Parameters
channel:subclass of SSHChannelUndocumented
extra:bytesUndocumented
def sendClose(self, channel): (source)

Close a channel.

Parameters
channel:subclass of SSHChannelUndocumented
def sendData(self, channel, data): (source)

Send data to a channel. This should not normally be used: instead use channel.write(data) as it manages the window automatically.

Parameters
channel:subclass of SSHChannelUndocumented
data:bytesUndocumented
def sendEOF(self, channel): (source)

Send an EOF (End of File) for a channel.

Parameters
channel:subclass of SSHChannelUndocumented
def sendExtendedData(self, channel, dataType, data): (source)

Send extended data to a channel. This should not normally be used: instead use channel.writeExtendedData(data, dataType) as it manages the window automatically.

Parameters
channel:subclass of SSHChannelUndocumented
dataType:intUndocumented
data:bytesUndocumented
def sendGlobalRequest(self, request, data, wantReply=0): (source)

Send a global request for this connection. Current this is only used for remote->local TCP forwarding.

Parameters
request:bytesUndocumented
data:bytesUndocumented
wantReply:boolUndocumented
Returns
Deferred/NoneUndocumented
def sendRequest(self, channel, requestType, data, wantReply=0): (source)

Send a request to a channel.

Parameters
channel:subclass of SSHChannelUndocumented
requestType:bytesUndocumented
data:bytesUndocumented
wantReply:boolUndocumented
Returns
Deferred/NoneUndocumented
def serviceStopped(self): (source)

Called when the connection is stopped.

def ssh_CHANNEL_CLOSE(self, packet): (source)

The other side is closing its end; it does not want to receive any more data. Payload:

    uint32  local channel number

Notify the channnel by calling its closeReceived() method. If the channel has also sent a close message, call self.channelClosed().

def ssh_CHANNEL_DATA(self, packet): (source)

The other side is sending us data. Payload:

    uint32 local channel number
    string data

Check to make sure the other side hasn't sent too much data (more than what's in the window, or more than the maximum packet size). If they have, close the channel. Otherwise, decrease the available window and pass the data to the channel's dataReceived().

def ssh_CHANNEL_EOF(self, packet): (source)

The other side is not sending any more data. Payload:

    uint32  local channel number

Notify the channel by calling its eofReceived() method.

def ssh_CHANNEL_EXTENDED_DATA(self, packet): (source)

The other side is sending us exteneded data. Payload:

    uint32  local channel number
    uint32  type code
    string  data

Check to make sure the other side hasn't sent too much data (more than what's in the window, or than the maximum packet size). If they have, close the channel. Otherwise, decrease the available window and pass the data and type code to the channel's extReceived().

def ssh_CHANNEL_FAILURE(self, packet): (source)

Our channel request to the other side failed. Payload:

    uint32  local channel number

Get the Deferred out of self.deferreds and errback it with a error.ConchError.

def ssh_CHANNEL_OPEN(self, packet): (source)

The other side wants to get a channel. Payload:

    string  channel name
    uint32  remote channel number
    uint32  remote window size
    uint32  remote maximum packet size
    <channel specific data>

We get a channel from self.getChannel(), give it a local channel number and notify the other side. Then notify the channel by calling its channelOpen method.

def ssh_CHANNEL_OPEN_CONFIRMATION(self, packet): (source)

The other side accepted our MSG_CHANNEL_OPEN request. Payload:

    uint32  local channel number
    uint32  remote channel number
    uint32  remote window size
    uint32  remote maximum packet size
    <channel specific data>

Find the channel using the local channel number and notify its channelOpen method.

def ssh_CHANNEL_OPEN_FAILURE(self, packet): (source)

The other side did not accept our MSG_CHANNEL_OPEN request. Payload:

    uint32  local channel number
    uint32  reason code
    string  reason description

Find the channel using the local channel number and notify it by calling its openFailed() method.

def ssh_CHANNEL_REQUEST(self, packet): (source)

The other side is sending a request to a channel. Payload:

    uint32  local channel number
    string  request name
    bool    want reply
    <request specific data>

Pass the message to the channel's requestReceived method. If the other side wants a reply, add callbacks which will send the reply.

def ssh_CHANNEL_SUCCESS(self, packet): (source)

Our channel request to the other side succeeded. Payload:

    uint32  local channel number

Get the Deferred out of self.deferreds and call it back.

def ssh_CHANNEL_WINDOW_ADJUST(self, packet): (source)

The other side is adding bytes to its window. Payload:

    uint32  local channel number
    uint32  bytes to add

Call the channel's addWindowBytes() method to add new bytes to the remote window.

def ssh_GLOBAL_REQUEST(self, packet): (source)

The other side has made a global request. Payload:

    string  request type
    bool    want reply
    <request specific data>

This dispatches to self.gotGlobalRequest.

def ssh_REQUEST_FAILURE(self, packet): (source)

Our global request failed. Get the appropriate Deferred and errback it with the packet we received.

def ssh_REQUEST_SUCCESS(self, packet): (source)

Our global request succeeded. Get the appropriate Deferred and call it back with the packet we received.

channels: dict = (source)

a dict mapping a local channel ID to SSHChannel subclasses.

channelsToRemoteChannel: dict = (source)

a dict mapping a SSHChannel subclass to remote channel ID.

deferreds: dict[str, list] = (source)

a dict mapping a local channel ID to a list of Deferreds for outstanding channel requests. Also, the 'global' key stores the list of pending global request Deferreds.

localChannelID: int = (source)

the next number to use as a local channel ID.

localToRemoteChannel: dict = (source)

a dict mapping a local channel ID to a remote channel ID.

def _cbChannelRequest(self, result, localChannel): (source)

Called back if the other side wanted a reply to a channel request. If the result is true, send a MSG_CHANNEL_SUCCESS. Otherwise, raise a error.ConchError

Parameters
result:boolthe value returned from the channel's requestReceived() method. If it's False, the request failed.
localChannel:intthe local channel ID of the channel to which the request was made.
Raises
ConchErrorif the result is False.
def _cleanupGlobalDeferreds(self): (source)

All pending requests that have returned a deferred must be errbacked when this service is stopped, otherwise they might be left uncalled and uncallable.

def _ebChannelRequest(self, result, localChannel): (source)

Called if the other wisde wanted a reply to the channel requeset and the channel request failed.

Parameters
resulta Failure, but it's not used.
localChannel:intthe local channel ID of the channel to which the request was made.