tcpcl package

The TCPCLv4 demonstration messaging and CL agent.

Subpackages

Submodules

Implementation of a symmetric TCPCL agent.

class tcpcl.agent.AddressObject(text, proto=6)

Bases: object

Interpret a text address as an ipaddress object.

Parameters:

text (Optional[str]) – The input to convert.

class tcpcl.agent.Conversation(family=None, peer_address=None, peer_port=None, local_address=None, local_port=None)

Bases: object

Bookkeep parameters of a TCP conversation which is address-and-port for each side.

family: Optional[int] = None
peer_address: Optional[_BaseAddress] = None
peer_port: Optional[int] = None
local_address: Optional[_BaseAddress] = None
local_port: Optional[int] = None
property key
make_socket()

Get a socket based on local requirements. :return: A TCP socket object.

class tcpcl.agent.Agent(config, bus_kwargs=None)

Bases: Object

Overall agent behavior.

Parameters:

  • config (Config) – The agent configuration object.

  • bus_kwargs (dict or None) – Arguments to dbus.service.Object constructor. If not provided the default dbus configuration is used.

DBUS_IFACE = 'org.ietf.dtn.tcpcl.Agent'
set_on_stop(func)

Set a callback to be run when this agent is stopped.

Parameters:

func – The callback, which takes no arguments.

get_connections()

Get all connections for this agent. :return: List of object paths.

connection_opened(*args, **keywords)

Emitted when a connection is opened.

connection_closed(*args, **keywords)

Emitted when a connection is closed.

shutdown()

Gracefully terminate all open sessions. Once the sessions are closed then the agent may stop.

Returns:

True if the agent is stopped immediately or False if a wait is needed.

stop()

Immediately stop the agent and disconnect any sessions.

exec_loop()

Run this agent in an event loop. The on_stop callback is replaced to quit the event loop.

listen(address, port)

Begin listening for incoming connections and defer handling connections to glib event loop.

listen_stop(address, port)

Stop listening for connections on an existing port binding.

connect(address, port)

Initiate an outgoing connection and defer handling state to glib event loop.

Parameters:

  • address (str) – The address to connect to.

  • port (int) – The port number to connect to.

Return type:

str

Returns:

The new contact object path.

handler_for_path(path)

Look up a contact by its object path.

Command entry points.

tcpcl.cmd.root_logging(log_level)

Initialize logging.

tcpcl.cmd.main()

Agent command entry point.

Agent configuration data.

class tcpcl.config.ListenConfig(address, port=4556)

Bases: object

address: str
port: int = 4556
class tcpcl.config.ConnectConfig(address, port=4556)

Bases: object

address: str
port: int = 4556
class tcpcl.config.Config(log_level=None, enable_test=<factory>, bus_addr=None, bus_service=None, init_listen=<factory>, init_connect=<factory>, stop_on_close=False, tls_enable=True, tls_version=None, tls_ciphers=None, tls_ca_file=None, tls_cert_file=None, tls_key_file=None, tls_dhparam=None, require_tls=None, require_host_authn=False, require_node_authn=False, node_id='', keepalive_time=0, idle_time=0, segment_size_mru=10485760, segment_size_tx_initial=104857, modulate_target_ack_time=None)

Bases: object

Agent configuration.

log_level: Optional[str] = None
enable_test: Set[str]
bus_addr: Optional[str] = None
bus_service: Optional[str] = None
init_listen: List[ListenConfig]
init_connect: List[ConnectConfig]
stop_on_close: bool = False
tls_enable: bool = True
tls_version: Optional[str] = None
tls_ciphers: Optional[Set[str]] = None
tls_ca_file: Optional[str] = None
tls_cert_file: Optional[str] = None
tls_key_file: Optional[str] = None
tls_dhparam: Optional[str] = None
require_tls: Optional[bool] = None
require_host_authn: bool = False
require_node_authn: bool = False
node_id: str = ''
keepalive_time: int = 0
idle_time: int = 0
segment_size_mru: int = 10485760
segment_size_tx_initial: int = 104857
modulate_target_ack_time: Optional[int] = None
from_file(fileobj)

Load configuration from a YAML file. :type fileobj: :param fileobj: The file to read from.

property bus_conn
get_ssl_context()

Get an ssl.SSLContext object configured for this peer.

Items related to contact header and connection negotiation.

class tcpcl.contact.Head(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: Packet

Front elements common to the TCPCL contact headers.

fields_desc: List[AnyField] = [<StrFixedLenField (Head).magic>, <UInt8Field (Head).version>]
aliastypes = [<class 'tcpcl.contact.Head'>, <class 'scapy.packet.Packet'>]
payload_guess: List[Tuple[Dict[str, Any], Type[Packet]]] = [({'version': 3}, <class 'tcpcl.contact.ContactV3'>), ({'version': 4}, <class 'tcpcl.contact.ContactV4'>)]
class tcpcl.contact.ContactV3(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

TCPCLv3 contact header pseudo-message.

class Flag(*values)

Bases: IntEnum

ENA_ACK = 1
ENA_FRAG = 2
ENA_REFUSE = 4
ENA_LENGTH = 8
fields_desc: List[AnyField] = [<FlagsField (ContactV3).flags>, <UInt16Field (ContactV3).keepalive>, <SdnvFieldLenField (ContactV3).nodeid_length>, <StrLenField (ContactV3).nodeid_data>]
post_dissection(pkt)

Verify consistency of packet.

aliastypes = [<class 'tcpcl.contact.ContactV3'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
class tcpcl.contact.ContactV4(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

TCPCLv4 Contact header pseudo-message.

SIZE_MAX = 18446744073709551615
class Flag(*values)

Bases: IntEnum

CAN_TLS = 1
fields_desc: List[AnyField] = [<FlagsField (ContactV4).flags>]
aliastypes = [<class 'tcpcl.contact.ContactV4'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]

Session and Transfer extension type definitions.

class tcpcl.extend.SessionPrivateDummy(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

Example of session extension.

fields_desc: List[AnyField] = [<UInt64Field (SessionPrivateDummy).largeval>, <UInt16Field (SessionPrivateDummy).smallval>]
aliastypes = [<class 'tcpcl.extend.SessionPrivateDummy'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
class tcpcl.extend.TransferPrivateDummy(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

Example of session extension.

fields_desc: List[AnyField] = [<UInt64Field (TransferPrivateDummy).largeval>, <UInt16Field (TransferPrivateDummy).smallval>]
aliastypes = [<class 'tcpcl.extend.TransferPrivateDummy'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
class tcpcl.extend.TransferTotalLength(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

Identify total transfer (bundle) length.

fields_desc: List[AnyField] = [<UInt64Field (TransferTotalLength).total_length>]
aliastypes = [<class 'tcpcl.extend.TransferTotalLength'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]

Created on May 29, 2016

@author: bsipos

class tcpcl.formats.UInt8Field(name, default)

Bases: Field

Unsigned 8-bit value.

class tcpcl.formats.UInt16Field(name, default)

Bases: Field

Unsigned 16-bit value.

class tcpcl.formats.UInt64Field(name, default)

Bases: Field

Unsigned 64-bit value.

class tcpcl.formats.UInt16FieldLenField(*args, **kwargs)

Bases: FieldLenField

Unsigned 16-bit value.

class tcpcl.formats.UInt32FieldLenField(*args, **kwargs)

Bases: FieldLenField

Unsigned 32-bit value.

class tcpcl.formats.UInt64FieldLenField(*args, **kwargs)

Bases: FieldLenField

Unsigned 64-bit value.

class tcpcl.formats.UInt16PayloadLenField(*args, **kwargs)

Bases: LenField

Unsigned 16-bit value.

class tcpcl.formats.SdnvField(name, default, fmt='H')

Bases: SDNV2

Represent a single independent SDNV-encoded integer.

class tcpcl.formats.SdnvFieldLenField(name, default, length_of=None, fmt='H', count_of=None, adjust=<function FieldLenField.<lambda>>)

Bases: SDNV2FieldLenField

An SDNV value which represents a count/length of another field.

class tcpcl.formats.SdnvPayloadLenField(name, default, fmt='H', adjust=<function LenField.<lambda>>)

Bases: SDNV2LenField

An SDNV value which represents the octet length of the payload data.

class tcpcl.formats.ExtensionListField(name, default, pkt_cls=None, count_from=None, length_from=None, next_cls_cb=None, max_count=None)

Bases: PacketListField

Provide useful randval() that fixes scapy behavior.

randval()

Return a volatile object whose value is both random and suitable for this field

class tcpcl.formats.StrLenFieldUtf8(name, default, length_from=None, max_length=None)

Bases: StrLenField

A UTF-8 safe text string.

h2i(pkt, x)

Convert human value to internal value

i2h(pkt, x)

Convert internal value to human value

randval()

Return a volatile object whose value is both random and suitable for this field

class tcpcl.formats.BlobField(name, default, length_from=None, max_length=None)

Bases: StrLenField

Overload i2h and i2repr to hide the actual data contents.

i2h(pkt, x)

Convert internal value to human value

i2repr(pkt, x)

Convert internal value to a nice representation

class tcpcl.formats.NoPayloadPacket(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: Packet

A packet which never contains payload data.

extract_padding(s)

No payload, all extra data is padding

aliastypes = [<class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
tcpcl.formats.remove_padding(pkt)

Traverse a packet and remove any trailing padding payload.

Parameters:

pkt (Packet) – The root packet to traverse.

exception tcpcl.formats.VerifyError

Bases: RuntimeError

An exception to indicate a read verification error.

tcpcl.formats.verify_sized_item(length, item)

Verify consistency of reading a sized item. :type length: Optional[int] :param length: The expected size of the field/packet. :type item: Packet :param item: The field or packet to take size of. :raise VerifyError: if inconsistent.

Return type:

None

Items related to established connection messaging.

class tcpcl.messages.MessageHead(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: Packet

The common message header.

fields_desc: List[AnyField] = [<UInt8Field (MessageHead).msg_id>]
post_dissection(pkt)

remove padding from payload list after disect() completes

aliastypes = [<class 'tcpcl.messages.MessageHead'>, <class 'scapy.packet.Packet'>]
payload_guess: List[Tuple[Dict[str, Any], Type[Packet]]] = [({'msg_id': 1}, <class 'tcpcl.messages.TransferSegment'>), ({'msg_id': 2}, <class 'tcpcl.messages.TransferAck'>), ({'msg_id': 3}, <class 'tcpcl.messages.TransferRefuse'>), ({'msg_id': 4}, <class 'tcpcl.messages.Keepalive'>), ({'msg_id': 5}, <class 'tcpcl.messages.SessionTerm'>), ({'msg_id': 6}, <class 'tcpcl.messages.RejectMsg'>), ({'msg_id': 7}, <class 'tcpcl.messages.SessionInit'>)]
class tcpcl.messages.TlvHead(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: Packet

Generic TLV header with data as payload.

classmethod bind_extension(ext_id)

Bind an extension class to a derived header class. This decorator should be applied to extension type classes.

Parameters:

  • cls – The header class to extend.

  • ext_id – The extension type ID number.

class Flag(*values)

Bases: IntEnum

Message flags. Flags must be in LSbit-first order.

CRITICAL = 1
fields_desc: List[AnyField] = [<FlagsField (TlvHead,SessionExtendHeader,TransferExtendHeader).flags>, <UInt16Field (TlvHead,SessionExtendHeader,TransferExtendHeader).type>, <UInt16PayloadLenField (TlvHead,SessionExtendHeader,TransferExtendHeader).length>]
post_dissection(pkt)

Verify consistency of packet.

aliastypes = [<class 'tcpcl.messages.TlvHead'>, <class 'scapy.packet.Packet'>]
class tcpcl.messages.SessionExtendHeader(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: TlvHead

Session Extension Item header with data as payload.

aliastypes = [<class 'tcpcl.messages.SessionExtendHeader'>, <class 'tcpcl.messages.TlvHead'>, <class 'scapy.packet.Packet'>]
fields_desc: List[AnyField] = [<FlagsField (TlvHead,SessionExtendHeader,TransferExtendHeader).flags>, <UInt16Field (TlvHead,SessionExtendHeader,TransferExtendHeader).type>, <UInt16PayloadLenField (TlvHead,SessionExtendHeader,TransferExtendHeader).length>]
payload_guess: List[Tuple[Dict[str, Any], Type[Packet]]] = [({'type': 255}, <class 'tcpcl.extend.SessionPrivateDummy'>)]
class tcpcl.messages.SessionInit(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

An SESS_INIT with no payload.

SIZE_MAX = 18446744073709551615
fields_desc: List[AnyField] = [<UInt16Field (SessionInit).keepalive>, <UInt64Field (SessionInit).segment_mru>, <UInt64Field (SessionInit).transfer_mru>, <UInt16FieldLenField (SessionInit).nodeid_length>, <StrLenFieldUtf8 (SessionInit).nodeid_data>, <UInt32FieldLenField (SessionInit).ext_size>, <ExtensionListField (SessionInit).ext_items>]
post_dissection(pkt)

Verify consistency of packet.

aliastypes = [<class 'tcpcl.messages.SessionInit'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
class tcpcl.messages.SessionTerm(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

An flag-dependent SESS_TERM message.

class Flag(*values)

Bases: IntEnum

Message flags. Flags must be in LSbit-first order.

REPLY = 1
class Reason(*values)

Bases: IntEnum

Reason code points.

UNKNOWN = 0
IDLE_TIMEOUT = 1
VERSION_MISMATCH = 2
BUSY = 3
CONTACT_FAILURE = 4
RESOURCE_EXHAUSTION = 5
fields_desc: List[AnyField] = [<FlagsField (SessionTerm).flags>, <ByteEnumField (SessionTerm).reason>]
aliastypes = [<class 'tcpcl.messages.SessionTerm'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
class tcpcl.messages.Keepalive(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

An empty KEEPALIVE message.

aliastypes = [<class 'tcpcl.messages.Keepalive'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
class tcpcl.messages.RejectMsg(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

A REJECT with no payload.

class Reason(*values)

Bases: IntEnum

Reason code points.

UNKNOWN = 1
UNSUPPORTED = 2
UNEXPECTED = 3
fields_desc: List[AnyField] = [<UInt8Field (RejectMsg).rej_msg_id>, <ByteEnumField (RejectMsg).reason>]
aliastypes = [<class 'tcpcl.messages.RejectMsg'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
class tcpcl.messages.TransferExtendHeader(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: TlvHead

Transfer Extension Item header with data as payload.

aliastypes = [<class 'tcpcl.messages.TransferExtendHeader'>, <class 'tcpcl.messages.TlvHead'>, <class 'scapy.packet.Packet'>]
fields_desc: List[AnyField] = [<FlagsField (TlvHead,SessionExtendHeader,TransferExtendHeader).flags>, <UInt16Field (TlvHead,SessionExtendHeader,TransferExtendHeader).type>, <UInt16PayloadLenField (TlvHead,SessionExtendHeader,TransferExtendHeader).length>]
payload_guess: List[Tuple[Dict[str, Any], Type[Packet]]] = [({'type': 255}, <class 'tcpcl.extend.TransferPrivateDummy'>), ({'type': 1}, <class 'tcpcl.extend.TransferTotalLength'>)]
class tcpcl.messages.TransferRefuse(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

An XFER_REFUSE with no payload.

class Reason(*values)

Bases: IntEnum

Reason code points.

UNKNOWN = 0
COMPLETED = 1
NO_RESOURCES = 2
RETRANSMIT = 3
NOT_ACCEPTABLE = 4
EXT_FAILURE = 5
fields_desc: List[AnyField] = [<ByteEnumField (TransferRefuse).reason>, <UInt64Field (TransferRefuse).transfer_id>]
aliastypes = [<class 'tcpcl.messages.TransferRefuse'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
class tcpcl.messages.TransferSegment(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

A XFER_SEGMENT with bundle data as field.

class Flag(*values)

Bases: IntEnum

Message flags. Flags must be in LSbit-first order.

END = 1
START = 2
fields_desc: List[AnyField] = [<FlagsField (TransferSegment).flags>, <UInt64Field (TransferSegment).transfer_id>, <scapy.fields.ConditionalField object>, <scapy.fields.ConditionalField object>, <UInt64FieldLenField (TransferSegment).length>, <BlobField (TransferSegment).data>]
post_dissection(pkt)

Verify consistency of packet.

aliastypes = [<class 'tcpcl.messages.TransferSegment'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]
class tcpcl.messages.TransferAck(_pkt=b'', post_transform=None, _internal=0, _underlayer=None, _parent=None, stop_dissection_after=None, **fields)

Bases: NoPayloadPacket

An XFER_ACK with no payload.

fields_desc: List[AnyField] = [<FlagsField (TransferAck).flags>, <UInt64Field (TransferAck).transfer_id>, <UInt64Field (TransferAck).length>]
aliastypes = [<class 'tcpcl.messages.TransferAck'>, <class 'tcpcl.formats.NoPayloadPacket'>, <class 'scapy.packet.Packet'>]

TCPCL session keeping and message sequencing.

tcpcl.session.match_id(ref_id, cert, san_key, logger, log_name)

Match a certificate identifier. :type san_key: :param san_key: A SAN type to match, or an OID of an OtherName to match. :return: The matched ID URI, or False if present but failed, or None if no identifier present in the certificate.

class tcpcl.session.Connection(sock, as_passive, peer_name)

Bases: object

Optionally secured socket connection. This handles octet-level buffering and queuing.

Parameters:

  • sock (socket.socket) – The unsecured socket to wrap.

  • as_passive (bool) – True if this is the passive side of the connection.

  • peer_name (str) – The name of the socket peer.

is_secure()

Determine if TLS is established.

Returns:

True if operating with TLS.

get_app_socket()

Get the socket object used for TCPCL traffic.

Returns:

The socket object.

get_secure_socket()

Get the secure socket object if available.

Returns:

The socket object or None.

set_on_close(func)

Set a callback to be run when this connection is closed.

Parameters:

func – The callback, which takes no arguments.

close()

Close the entire connection cleanly.

secure(ssl_ctx)

Add a TLS connection layer (if not present).

Parameters:

ssl_ctx (ssl.SSLContext) – The context to use for security.

Raises:

ssl.SSLError – If the negotiation fails.

unsecure()

Remove any TLS connection layer (if present).

CHUNK_SIZE = 10240
DO_DEBUG_DATA = False
recv_raw(data)

Handler for a received block of data. Derived classes must overload this method to handle RX data.

Parameters:

data (str) – The received data.

send_ready()

Called to indicate that send_raw() will return non-empty. This will attempt immediate transmit of chunks if available, and queue the rest for later.

send_raw(size)

Obtain a block of data to send. Derived classes must overload this method to return TX data.

Parameters:

size (int) – The maximum size to obtain.

Returns:

The to-be-transmitted data.

Return type:

str

exception tcpcl.session.RejectError(reason=None)

Bases: Exception

Allow recv_* handlers to reject the message.

Parameters:

reason (Optional[int]) – The rejection reason. Should be one of the messages.RejectMsg.Reason values.

exception tcpcl.session.TerminateError(reason=None)

Bases: Exception

Allow recv_* handlers to terminate a session.

Parameters:

reason (Optional[int]) – The termination reason. Should be one of the messages.SessionTerm.Reason values.

class tcpcl.session.Messenger(config, sock, fromaddr=None, toaddr=None)

Bases: Connection

Messaging layer of TCPCL. This handles message-level buffering and queuing. Messages are variable-length individually.

Parameters:

  • config (Config) – The messenger configuration struct.

  • sock (socket.socket) – The (unsecured) connection socket to operate on.

set_on_state_change(func)

Set a callback to be run when this session state changes.

Parameters:

func – The callback, which takes argument of the new state name.

is_passive()

Determine if this is the passive side of the session.

is_sess_idle()

Determine if the session is idle.

Returns:

True if there are no data being processed RX or TX side.

set_on_session_start(func)

Set a callback to be run when this session is started.

Parameters:

func – The callback, which takes no arguments.

set_on_session_terminate(func)

Set a callback to be run when this session is terminated.

Parameters:

func – The callback, which takes no arguments.

recv_buffer_used()

Get the number of octets waiting in the receive buffer.

Returns:

The buffer use (octets).

Return type:

int.

send_buffer_used()

Get the number of octets waiting in the transmit buffer.

Returns:

The buffer use (octets).

Return type:

int.

send_buffer_decreased(buf_use)

A handler function to be used when message buffer data is transmitted.

Parameters:

buf_use (int) – The current buffer use (octets).

close()

Close the entire connection cleanly.

recv_raw(data)

Attempt to extract a message from the current read buffer.

recv_message(pkt)

Handle a received full message (or contact header).

Parameters:

pkt – The message packet received.

send_contact_header()

Send the initial Contact Header non-message. Parameters are based on current configuration.

merge_contact_params()

Combine local and peer contact headers to contact configuration.

send_sess_init()

Send the initial SESS_INIT message. Parameters are based on current configuration.

merge_session_params()

Combine local and peer SESS_INIT parameters. The result is kept in _sess_parameters.

Raises:

TerminateError – If there is some failure to negotiate.

send_raw(size)

Pop some data from the TX queue.

Parameters:

size – The maximum size to pop from the queue.

Returns:

The chunk of data popped from the queue.

Return type:

bytes

send_message(pkt)

Send a full message (or contact header).

Parameters:

pkt – The message packet to send.

send_reject(reason, pkt=None)

Send a message rejection response.

Parameters:

  • reason (int) – The reject reason code.

  • pkt (The orignal MessageHead packet.) – The message being rejected (optional).

send_sess_term(reason, is_reply)

Send the SESS_TERM message. After calling this method no further transfers can be started.

start()

Main state machine of the agent contact.

recv_sess_term(reason)

Handle reception of SESS_TERM message.

Parameters:

reason (int) – The termination reason.

recv_xfer_data(transfer_id, flags, data, ext_items)

Handle reception of XFER_DATA message.

Parameters:

  • transfer_id (int) – The bundle ID number.

  • flags (int) – The transfer flags.

  • data (str) – The segment data.

  • ext_items (array) – Extension items which may be in the start segment.

recv_xfer_ack(transfer_id, flags, length)

Handle reception of XFER_ACK message.

Parameters:

  • transfer_id (int) – The bundle ID number.

  • flags (int) – The transfer flags.

  • length (int) – The acknowledged length.

recv_xfer_refuse(transfer_id, reason)

Handle reception of XFER_REFUSE message.

Parameters:

  • transfer_id (int) – The bundle ID number.

  • reason (int) – The refusal reason code.

send_xfer_data(transfer_id, data, flg, ext_items=None)

Send a XFER_DATA message.

Parameters:

  • transfer_id (int) – The bundle ID number.

  • data (str) – The segment data.

  • flg (int) – Data flags for TransferSegment

  • ext_items (list or None) – Extension items for the starting segment only.

send_xfer_ack(transfer_id, length, flg)

Send a XFER_ACK message.

Parameters:

  • transfer_id (int) – The bundle ID number.

  • length (int) – The acknowledged length.

  • flg (int) – Data flags for TransferAck

send_xfer_refuse(transfer_id, reason)

Send a XFER_REFUSE message.

Parameters:

  • transfer_id (int) – The bundle ID number.

  • reason (int) – The refusal reason code.

class tcpcl.session.BundleItem

Bases: object

State for RX and TX full bundles.

transfer_id The unique transfer ID number.
total_length The length from the file (sender) or
known from the Transfer Length extension (receiver)
ack_length The total acknowledged length.
class tcpcl.session.ContactHandler(hdl_kwargs, bus_kwargs)

Bases: Messenger, Object

A bus interface to the contact message handler.

Parameters:

  • hdl_kwargs (dict) – Arguments to Messenger constructor.

  • bus_kwargs (dict) – Arguments to dbus.service.Object constructor.

DBUS_IFACE = 'org.ietf.dtn.tcpcl.Contact'
get_session_state()
session_state_changed(*args, **keywords)
get_session_parameters()
next_id()

Get the next available transfer ID number.

Returns:

A valid transfer ID.

Return type:

int

recv_sess_term(reason)

Handle reception of SESS_TERM message.

Parameters:

reason (int) – The termination reason.

recv_xfer_data(transfer_id, flags, data, ext_items)

Handle reception of XFER_DATA message.

Parameters:

  • transfer_id (int) – The bundle ID number.

  • flags (int) – The transfer flags.

  • data (str) – The segment data.

  • ext_items (array) – Extension items which may be in the start segment.

recv_xfer_ack(transfer_id, flags, length)

Handle reception of XFER_ACK message.

Parameters:

  • transfer_id (int) – The bundle ID number.

  • flags (int) – The transfer flags.

  • length (int) – The acknowledged length.

recv_xfer_refuse(transfer_id, reason)

Handle reception of XFER_REFUSE message.

Parameters:

  • transfer_id (int) – The bundle ID number.

  • reason (int) – The refusal reason code.

is_secure()

Determine if TLS is established.

Returns:

True if operating with TLS.

is_sess_idle()

Determine if the session is idle.

Returns:

True if there are no data being processed RX or TX side.

terminate(reason_code=None)

Perform the termination procedure.

Parameters:

reason_code (Optional[int]) – The termination reason. Should be one of the messages.SessionTerm.Reason values.

close()

Close the TCP connection immediately.

send_bundle_fileobj(file)

Send bundle from a file-like object.

Parameters:

file (file-like) – The file to send.

Returns:

The new transfer ID.

Return type:

int

send_bundle_data(data)

Send bundle data directly.

send_bundle_file(filepath)

Send a bundle from the filesystem.

send_bundle_get_queue()
send_bundle_started(*args, **keywords)
send_bundle_intermediate(*args, **keywords)
send_bundle_finished(*args, **keywords)
recv_bundle_started(*args, **keywords)
recv_bundle_intermediate(*args, **keywords)
recv_bundle_finished(*args, **keywords)
recv_bundle_get_queue()
recv_bundle_pop_data(bid)
recv_bundle_pop_file(bid, filepath)
send_buffer_decreased(buf_use)

A handler function to be used when message buffer data is transmitted.

Parameters:

buf_use (int) – The current buffer use (octets).