class documentation

class twisted.conch.ssh.connection.SSHConnection(service.SSHService): (source)

Known subclasses: twisted.conch.endpoints._ConnectionReady, twisted.conch.scripts.cftp.SSHConnection, twisted.conch.scripts.conch.SSHConnection, twisted.conch.scripts.tkconch.SSHConnection

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

Instance Variable localChannelID the next number to use as a local channel ID.
Instance Variable channels a dict mapping a local channel ID to SSHChannel subclasses.
Instance Variable localToRemoteChannel a dict mapping a local channel ID to a remote channel ID.
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.
Class Variable name Undocumented
Method __init__ Undocumented
Instance Variable transport Undocumented
Method serviceStarted called when the service is active on the transport.
Method serviceStopped Called when the connection is stopped.
Method ssh_GLOBAL_REQUEST No summary
Method ssh_REQUEST_SUCCESS Our global request succeeded. Get the appropriate Deferred and call it back with the packet we received.
Method ssh_REQUEST_FAILURE Our global request failed. Get the appropriate Deferred and errback it with the packet we received.
Method ssh_CHANNEL_OPEN No summary
Method ssh_CHANNEL_OPEN_CONFIRMATION No summary
Method ssh_CHANNEL_OPEN_FAILURE No summary
Method ssh_CHANNEL_WINDOW_ADJUST The other side is adding bytes to its window. Payload:: uint32 local channel number uint32 bytes to add
Method ssh_CHANNEL_DATA The other side is sending us data. Payload:: uint32 local channel number string data
Method ssh_CHANNEL_EXTENDED_DATA No summary
Method ssh_CHANNEL_EOF The other side is not sending any more data. Payload:: uint32 local channel number
Method ssh_CHANNEL_CLOSE The other side is closing its end; it does not want to receive any more data. Payload:: uint32 local channel number
Method ssh_CHANNEL_REQUEST No summary
Method ssh_CHANNEL_SUCCESS Our channel request to the other side succeeded. Payload:: uint32 local channel number
Method ssh_CHANNEL_FAILURE Our channel request to the other side failed. Payload:: uint32 local channel number
Method sendGlobalRequest Send a global request for this connection. Current this is only used for remote->local TCP forwarding.
Method openChannel Open a new channel on this connection.
Method sendRequest Send a request to a channel.
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 sendData Send data to a channel. This should not normally be used: instead use channel.write(data) as it manages the window automatically.
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 sendEOF Send an EOF (End of File) for a channel.
Method sendClose Close a channel.
Method getChannel No summary
Method gotGlobalRequest No summary
Method channelClosed No summary
Class Variable _log Undocumented
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 _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 _ebChannelRequest Called if the other wisde wanted a reply to the channel requeset and the channel request failed.

Inherited from SSHService:

Class Variable protocolMessages Undocumented
Method logPrefix Undocumented
Method packetReceived called when we receive a packet on the transport
localChannelID = (source)
the next number to use as a local channel ID.
(type: int)
channels = (source)
a dict mapping a local channel ID to SSHChannel subclasses.
(type: dict)
localToRemoteChannel = (source)
a dict mapping a local channel ID to a remote channel ID.
(type: dict)
channelsToRemoteChannel = (source)
a dict mapping a SSHChannel subclass to remote channel ID.
(type: dict)
deferreds = (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.
(type: dict[str, list])
def __init__(self): (source)

Undocumented

def serviceStopped(self): (source)

Called when the connection is stopped.

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 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_SUCCESS(self, packet): (source)

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

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_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_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_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_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_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_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_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 _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

Parametersresultthe value returned from the channel's requestReceived() method. If it's False, the request failed. (type: bool)
localChannelthe local channel ID of the channel to which the request was made. (type: int)
RaisesConchErrorif the result is False.
def _ebChannelRequest(self, result, localChannel): (source)

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

Parametersresulta Failure, but it's not used.
localChannelthe local channel ID of the channel to which the request was made. (type: int)
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_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 sendGlobalRequest(self, request, data, wantReply=0): (source)

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

ParametersrequestUndocumented (type: bytes)
dataUndocumented (type: bytes)
wantReplyUndocumented (type: bool)
ReturnsUndocumented (type: Deferred/None)
def openChannel(self, channel, extra=b''): (source)

Open a new channel on this connection.

ParameterschannelUndocumented (type: subclass of SSHChannel)
extraUndocumented (type: bytes)
def sendRequest(self, channel, requestType, data, wantReply=0): (source)

Send a request to a channel.

ParameterschannelUndocumented (type: subclass of SSHChannel)
requestTypeUndocumented (type: bytes)
dataUndocumented (type: bytes)
wantReplyUndocumented (type: bool)
ReturnsUndocumented (type: Deferred/None)
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.

ParameterschannelUndocumented (type: subclass of SSHChannel)
bytesToAddUndocumented (type: int)
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.

ParameterschannelUndocumented (type: subclass of SSHChannel)
dataUndocumented (type: bytes)
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.

ParameterschannelUndocumented (type: subclass of SSHChannel)
dataTypeUndocumented (type: int)
dataUndocumented (type: bytes)
def sendEOF(self, channel): (source)

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

ParameterschannelUndocumented (type: subclass of SSHChannel)
def sendClose(self, channel): (source)

Close a channel.

ParameterschannelUndocumented (type: subclass of SSHChannel)
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.

ParameterschannelTypeUndocumented (type: bytes)
windowSizeUndocumented (type: int)
maxPacketUndocumented (type: int)
dataUndocumented (type: bytes)
ReturnsUndocumented (type: subclass of SSHChannel/tuple)
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.

ParametersrequestTypeUndocumented (type: bytes)
dataUndocumented (type: bytes)
ReturnsUndocumented (type: int/tuple)
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.

ParameterschannelUndocumented (type: SSHChannel)
API Documentation for Twisted, generated by pydoctor 20.12.1 at 2021-02-28 19:53:36.