twisted.conch.ssh.transport.SSHTransportBase : API documentation

Protocol supporting basic SSH functionality: sending/receiving packets and message dispatch. To connect to or run a server, you must use SSHClientTransport or SSHServerTransport.

Instance Variables	protocolVersion	A string representing the version of the SSH protocol we support. Currently defaults to '2.0'.
	version	A string representing the version of the server or client. Currently defaults to 'Twisted'.
	comment	An optional string giving more information about the server or client.
	supportedCiphers	A list of strings representing the encryption algorithms supported, in order from most-preferred to least.
	supportedMACs	A list of strings representing the message authentication codes (hashes) supported, in order from most-preferred to least. Both this and supportedCiphers can include 'none' to use no encryption or authentication, but that must be done manually,
	supportedKeyExchanges	A list of strings representing the key exchanges supported, in order from most-preferred to least.
	supportedPublicKeys	A list of strings representing the public key types supported, in order from most-preferred to least.
	supportedCompressions	A list of strings representing compression types supported, from most-preferred to least.
	supportedLanguages	A list of strings representing languages supported, from most-preferred to least.
	supportedVersions	A container of strings representing supported ssh protocol version numbers.
	isClient	A boolean indicating whether this is a client or server.
	gotVersion	A boolean indicating whether we have receieved the version string from the other side.
	buf	Data we've received but hasn't been parsed into a packet.
	outgoingPacketSequence	the sequence number of the next packet we will send.
	incomingPacketSequence	the sequence number of the next packet we are expecting from the other side.
	outgoingCompression	an object supporting the .compress(str) and .flush() methods, or None if there is no outgoing compression. Used to compress outgoing data.
	outgoingCompressionType	A string representing the outgoing compression type.
	incomingCompression	an object supporting the .decompress(str) method, or None if there is no incoming compression. Used to decompress incoming data.
	incomingCompressionType	A string representing the incoming compression type.
	ourVersionString	the version string that we sent to the other side. Used in the key exchange.
	otherVersionString	the version string sent by the other side. Used in the key exchange.
	ourKexInitPayload	the MSG_KEXINIT payload we sent. Used in the key exchange.
	otherKexInitPayload	the MSG_KEXINIT payload we received. Used in the key exchange
	sessionID	a string that is unique to this SSH session. Created as part of the key exchange, sessionID is used to generate the various encryption and authentication keys.
	service	an SSHService instance, or None. If it's set to an object, it's the currently running service.
	kexAlg	the agreed-upon key exchange algorithm.
	keyAlg	the agreed-upon public key type for the key exchange.
	currentEncryptions	an SSHCiphers instance. It represents the current encryption and authentication options for the transport.
	nextEncryptions	an SSHCiphers instance. Held here until the MSG_NEWKEYS messages are exchanged, when nextEncryptions is transitioned to currentEncryptions.
	first	the first bytes of the next packet. In order to avoid decrypting data twice, the first bytes are decrypted and stored until the whole packet is available.
	_keyExchangeState	The current protocol state with respect to key exchange. This is either `_KEY_EXCHANGE_NONE` if no key exchange is in progress (and returns to this value after any key exchange completes), `_KEY_EXCHANGE_REQUESTED` if this side of the connection initiated a key exchange, and `_KEY_EXCHANGE_PROGRESSING` if the other side of the connection initiated a key exchange. `_KEY_EXCHANGE_NONE` is the initial value (however SSH connections begin with key exchange, so it will quickly change to another state).
	_blockedByKeyExchange	Whenever `_keyExchangeState` is not `_KEY_EXCHANGE_NONE`, this is a `list` of pending messages which were passed to `sendPacket` but could not be sent because it is not legal to send them while a key exchange is in progress. When the key exchange completes, another attempt is made to send these messages.

Method	connectionLost	Called when the connection is shut down.
Method	connectionMade	Called when the connection is made to the other side. We sent our version and the MSG_KEXINIT packet.
Method	sendKexInit	Send a KEXINIT message to initiate key exchange or to respond to a key exchange initiated by the peer.
Method	sendPacket	Sends a packet. If it's been set up, compress the data, encrypt it, and authenticate it before sending. If key exchange is in progress and the message is not part of key exchange, queue it to be sent later.
Method	getPacket	Try to return a decrypted, authenticated, and decompressed packet out of the buffer. If there is not enough data, return None.
Method	dataReceived	First, check for the version string (SSH-2.0-*). After that has been received, this method adds data to the buffer, and pulls out any packets.
Method	dispatchMessage	Send a received message to the appropriate method.
Method	ssh_KEXINIT	No summary
Method	ssh_DISCONNECT	Called when we receive a MSG_DISCONNECT message. Payload:: long code string description
Method	ssh_IGNORE	Called when we receieve a MSG_IGNORE message. No payload. This means nothing; we simply return.
Method	ssh_UNIMPLEMENTED	Called when we receieve a MSG_UNIMPLEMENTED message. Payload:: long packet
Method	ssh_DEBUG	No summary
Method	setService	Set our service to service and start it running. If we were running a service previously, stop it first.
Method	sendDebug	Send a debug message to the other side.
Method	sendIgnore	Send a message that will be ignored by the other side. This is useful to fool attacks based on guessing packet sizes in the encrypted stream.
Method	sendUnimplemented	Send a message to the other side that the last packet was not understood.
Method	sendDisconnect	Send a disconnect message to the other side and then disconnect.
Method	isEncrypted	Return True if the connection is encrypted in the given direction. Direction must be one of ["out", "in", "both"].
Method	isVerified	Return True if the connecction is verified/authenticated in the given direction. Direction must be one of ["out", "in", "both"].
Method	loseConnection	Lose the connection to the other side, sending a DISCONNECT_CONNECTION_LOST message.
Method	receiveError	Called when we receive a disconnect error message from the other side.
Method	receiveUnimplemented	Called when we receive an unimplemented packet message from the other side.
Method	receiveDebug	Called when we receive a debug message from the other side.
Method	_allowedKeyExchangeMessageType	Determine if the given message type may be sent while key exchange is in progress.
Method	_unsupportedVersionReceived	Called when an unsupported version of the ssh protocol is received from the remote endpoint.
Method	_getKey	Get one of the keys for authentication/encryption.
Method	_keySetup	Set up the keys for the connection and sends MSG_NEWKEYS when finished,
Method	_newKeys	No summary

Inherited from BaseProtocol (via Protocol):

Method

makeConnection

Make a connection to a transport and a server.

Called when the connection is shut down.

Clear any circular references here, and any external references to this Protocol. The connection has been closed.

Parameters reason (type: twisted.python.failure.Failure )

Called when the connection is made to the other side. We sent our version and the MSG_KEXINIT packet.

Send a KEXINIT message to initiate key exchange or to respond to a key exchange initiated by the peer.

Returns	`None`
Raises	RuntimeError	If a key exchange has already been started and it is not appropriate to send a KEXINIT message at this time.

Determine if the given message type may be sent while key exchange is in progress.

Parameters	messageType	The type of message (type: `int` )
Returns	`True` if the given type of message may be sent while key exchange is in progress, `False` if it may not. (type: `bool` )
See Also	http://tools.ietf.org/html/rfc4253#section-7.1

Sends a packet. If it's been set up, compress the data, encrypt it, and authenticate it before sending. If key exchange is in progress and the message is not part of key exchange, queue it to be sent later.

Parameters	messageType	The type of the packet; generally one of the MSG_* values. (type: `int` )
	payload	The payload for the message. (type: `str` )

Try to return a decrypted, authenticated, and decompressed packet out of the buffer. If there is not enough data, return None.

Returns (type: str/None )

Called when an unsupported version of the ssh protocol is received from the remote endpoint.

Parameters remoteVersion remote ssh protocol version which is unsupported by us. (type: str )

First, check for the version string (SSH-2.0-*). After that has been received, this method adds data to the buffer, and pulls out any packets.

Parameters data (type: str )

Send a received message to the appropriate method.

Parameters	messageNum	(type: `int` )
	payload	(type: c{str} )

Called when we receive a MSG_KEXINIT message. Payload:

   bytes[16] cookie
   string keyExchangeAlgorithms
   string keyAlgorithms
   string incomingEncryptions
   string outgoingEncryptions
   string incomingAuthentications
   string outgoingAuthentications
   string incomingCompressions
   string outgoingCompressions
   string incomingLanguages
   string outgoingLanguages
   bool firstPacketFollows
   unit32 0 (reserved)

Starts setting up the key exchange, keys, encryptions, and authentications. Extended by ssh_KEXINIT in SSHServerTransport and SSHClientTransport.

Called when we receive a MSG_DISCONNECT message. Payload:

   long code
   string description

This means that the other side has disconnected. Pass the message up and disconnect ourselves.

Called when we receieve a MSG_IGNORE message. No payload. This means nothing; we simply return.

Called when we receieve a MSG_UNIMPLEMENTED message. Payload:

   long packet

This means that the other side did not implement one of our packets.

Called when we receieve a MSG_DEBUG message. Payload:

   bool alwaysDisplay
   string message
   string language

This means the other side has passed along some debugging info.

Set our service to service and start it running. If we were running a service previously, stop it first.

Parameters service (type: SSHService )

Send a debug message to the other side.

Parameters	message	the message to send. (type: `str` )
	alwaysDisplay	if True, tell the other side to always display this message. (type: `bool` )
	language	optionally, the language the message is in. (type: `str` )

Send a message that will be ignored by the other side. This is useful to fool attacks based on guessing packet sizes in the encrypted stream.

Parameters message data to send with the message (type: str )

Send a message to the other side that the last packet was not understood.

Send a disconnect message to the other side and then disconnect.

Parameters	reason	the reason for the disconnect. Should be one of the DISCONNECT_* values. (type: `int` )
	desc	a descrption of the reason for the disconnection. (type: `str` )

Get one of the keys for authentication/encryption.

Parameters	c	(type: `str` )
	sharedSecret	(type: `str` )
	exchangeHash	(type: `str` )

Set up the keys for the connection and sends MSG_NEWKEYS when finished,

Parameters	sharedSecret	a secret string agreed upon using a Diffie- Hellman exchange, so it is only shared between the server and the client. (type: `str` )
	exchangeHash	A hash of various data known by both sides. (type: `str` )

Called back by a subclass once a MSG_NEWKEYS message has been received. This indicates key exchange has completed and new encryption and compression parameters should be adopted. Any messages which were queued during key exchange will also be flushed.

Return True if the connection is encrypted in the given direction. Direction must be one of ["out", "in", "both"].

Return True if the connecction is verified/authenticated in the given direction. Direction must be one of ["out", "in", "both"].

Lose the connection to the other side, sending a DISCONNECT_CONNECTION_LOST message.

Called when we receive a disconnect error message from the other side.

Parameters	reasonCode	the reason for the disconnect, one of the DISCONNECT_ values. (type: `int` )
	description	a human-readable description of the disconnection. (type: `str` )

Called when we receive an unimplemented packet message from the other side.

Parameters seqnum the sequence number that was not understood. (type: int )

Called when we receive a debug message from the other side.

Parameters	alwaysDisplay	if True, this message should always be displayed. (type: `bool` )
	message	the debug message (type: `str` )
	lang	optionally the language the message is in. (type: `str` )

t.c.s.t.SSHTransportBase(protocol.Protocol) : class documentation