CFDP Package

Module contents

Please note that this module does not contain configuration helpers, for example to convert CLI or GUI parameters into the internalized CFDP classes. You can find all those helpers inside the tmtccmd.config.cfdp module.

class cfdppy.CfdpIndication(value)

Bases: Enum

An enumeration.

ABANDONED = 9

EOF = 1

EOF_RECV = 10

FAULT = 8

FILE_SEGMENT_RECV = 4

FINISHED = 2

METADATA = 3

REPORT = 5

RESUMED = 7

SUSPENDED = 6

TRANSACTION = 0

class cfdppy.CfdpState(value)

Bases: Enum

An enumeration.

BUSY = 1

IDLE = 0

SUSPENDED = 2

class cfdppy.CfdpUserBase(vfs: VirtualFilestore | None = None)

Bases: ABC

This user base class provides the primary user interface to interact with CFDP handlers. It is also used to pass the Virtual Filestore (VFS) implementation to the CFDP handlers so the filestore operations can be mapped to the underlying filestore.

This class is used by implementing it in a child class and then passing it to the CFDP handler objects. The base class provides default implementation for the user indication primitives specified in the CFDP standard. The user can override these implementations to provide custom indication handlers.

abstract abandoned_indication(transaction_id: TransactionId, cond_code: ConditionCode, progress: int) → None

This is the Fault.Indication as specified in chapter 3.4.15 of the standard.

The user implementation of this function could be used to keep a (failed) transaction history, which might be useful for the positive ACK procedures expected from a receiving CFDP entity.

abstract eof_recv_indication(transaction_id: TransactionId) → None

abstract eof_sent_indication(transaction_id: TransactionId) → None

abstract fault_indication(transaction_id: TransactionId, cond_code: ConditionCode, progress: int) → None

This is the Fault.Indication as specified in chapter 3.4.14 of the standard.

The user implementation of this function could be used to keep a (failed) transaction history, which might be useful for the positive ACK procedures expected from a receiving CFDP entity.

abstract file_segment_recv_indication(params: FileSegmentRecvdParams) → None

abstract metadata_recv_indication(params: MetadataRecvParams) → None

abstract report_indication(transaction_id: TransactionId, status_report: Any) → None

abstract resumed_indication(transaction_id: TransactionId, progress: int) → None

abstract suspended_indication(transaction_id: TransactionId, cond_code: ConditionCode) → None

abstract transaction_finished_indication(params: TransactionFinishedParams) → None

This is the Transaction-Finished.Indication as specified in chapter 3.4.8 of the standard.

The user implementation of this function could be used to keep a (failed) transaction history, which might be useful for the positive ACK procedures expected from a receiving CFDP entity.

abstract transaction_indication(transaction_indication_params: TransactionParams) → None: This indication is used to report the transaction ID to the CFDP user

cfdppy.HostFilestore: alias of NativeFilestore

class cfdppy.IndicationConfig(eof_sent_indication_required: 'bool' = True, eof_recv_indication_required: 'bool' = True, file_segment_recvd_indication_required: 'bool' = True, transaction_finished_indication_required: 'bool' = True, suspended_indication_required: 'bool' = True, resumed_indication_required: 'bool' = True)

Bases: object

eof_recv_indication_required: bool = True

eof_sent_indication_required: bool = True

file_segment_recvd_indication_required: bool = True

resumed_indication_required: bool = True

suspended_indication_required: bool = True

transaction_finished_indication_required: bool = True

class cfdppy.LocalEntityConfig(local_entity_id: UnsignedByteField, indication_cfg: IndicationConfig, default_fault_handlers: DefaultFaultHandlerBase)

Bases: object

This models the remote entity configuration information as specified in chapter 8.2 of the CFDP standard.

default_fault_handlers: DefaultFaultHandlerBase

indication_cfg: IndicationConfig

local_entity_id: UnsignedByteField

class cfdppy.PacketDestination(value)

Bases: Enum

An enumeration.

DEST_HANDLER = 1

SOURCE_HANDLER = 0

class cfdppy.PutRequest(destination_id: UnsignedByteField, source_file: Path | None, dest_file: Path | None, trans_mode: TransmissionMode | None, closure_requested: bool | None, seg_ctrl: SegmentationControl | None = SegmentationControl.NO_RECORD_BOUNDARIES_PRESERVATION, fault_handler_overrides: list[FaultHandlerOverrideTlv] | None = None, flow_label_tlv: FlowLabelTlv | None = None, msgs_to_user: list[MessageToUserTlv] | None = None, fs_requests: list[FileStoreRequestTlv] | None = None)

Bases: object

This is the base class modelling the CFDP put request.

You can create this class from the simplified tmtccmd.config.defs.CfdpParams class with the generic tmtccmd.config.cfdp.generic_cfdp_params_to_put_request() API and/or all related specific APIs.

closure_requested: bool | None

dest_file: Path | None

destination_id: UnsignedByteField

fault_handler_overrides: list[FaultHandlerOverrideTlv] | None = None

flow_label_tlv: FlowLabelTlv | None = None

fs_requests: list[FileStoreRequestTlv] | None = None

property metadata_only: bool

msgs_to_user: list[MessageToUserTlv] | None = None

seg_ctrl: SegmentationControl | None = 0

source_file: Path | None

trans_mode: TransmissionMode | None

class cfdppy.RemoteEntityConfig(entity_id: UnsignedByteField, max_file_segment_len: int | None, max_packet_len: int, closure_requested: bool, crc_on_transmission: bool, default_transmission_mode: TransmissionMode, crc_type: ChecksumType, positive_ack_timer_interval_seconds: float = 10.0, positive_ack_timer_expiration_limit: int = 2, check_limit: int = 2, disposition_on_cancellation: bool = False, immediate_nak_mode: bool = True, nak_timer_interval_seconds: float = 10.0, nak_timer_expiration_limit: int = 2, cfdp_version: int = 1)

Bases: object

This models the remote entity configuration information as specified in chapter 8.3 of the CFDP standard.

Some of the fields which were not considered necessary for the Python implementation were omitted. Some other fields which are not contained inside the standard but are considered necessary for the Python implementation are included.

Notes on Positive Acknowledgment Procedures

The positive_ack_timer_interval_seconds and positive_ack_timer_expiration_limit will be used for positive acknowledgment procedures as specified in CFDP chapter 4.7. The sending entity will start the timer for any PDUs where an acknowledgment is required (e.g. EOF PDU). Once the expected ACK response has not been received for that interval, as counter will be incremented and the timer will be reset. Once the counter exceeds the positive_ack_timer_expiration_limit, a Positive ACK Limit Reached fault will be declared.

Notes on Deferred Lost Segment Procedures

This procedure will be active if an EOF (No Error) PDU is received in acknowledged mode. After issuing the NAK sequence which has the whole file scope, a timer will be started. The timer is reset when missing segments or missing metadata is received. The timer will be deactivated if all missing data is received. If the timer expires, a new NAK sequence will be issued and a counter will be incremented, which can lead to a NAK Limit Reached fault being declared.

Parameters:

entity_id (UnsignedByteField) – The ID of the remote entity.
max_packet_len (int) – This determines of all PDUs generated for that remote entity in addition to the max_file_segment_len attribute which also determines the size of file data PDUs.
max_file_segment_len (int | None) – The maximum file segment length which determines the maximum size of file data PDUs in addition to the max_packet_len attribute. If this field is set to None, the maximum file segment length will be derived from the maximum packet length. If this has some value which is smaller than the segment value derived from max_packet_len, this value will be picked.
closure_requested (bool) – If the closure requested field is not supplied as part of the Put Request, it will be determined from this field in the remote configuration.
crc_on_transmission (bool) – If the CRC option is not supplied as part of the Put Request, it will be determined from this field in the remote configuration.
default_transmission_mode (TransmissionMode) – If the transmission mode is not supplied as part of the Put Request, it will be determined from this field in the remote configuration.
disposition_on_cancellation (bool) – Determines whether an incomplete received file is discard on transaction cancellation. Defaults to False.
crc_type (ChecksumType) – Default checksum type used to calculate for all file transmissions to this remote entity.
check_limit (int) – this timer determines the expiry period for incrementing a check counter after an EOF PDU is received for an incomplete file transfer. This allows out-of-order reception of file data PDUs and EOF PDUs. Also see 4.6.3.3 of the CFDP standard. Defaults to 2, so the check limit timer may expire twice.
positive_ack_timer_interval_seconds (float) – See the notes on the Positive Acknowledgment Procedures inside the class documentation. Expected as floating point seconds. Defaults to 10 seconds.
positive_ack_timer_expiration_limit (int) – See the notes on the Positive Acknowledgment Procedures inside the class documentation. Defaults to 2, so the timer may expire twice.
immediate_nak_mode (bool) – Specifies whether a NAK sequence should be issued immediately when a file data gap or lost metadata is detected in the acknowledged mode. Defaults to True.
nak_timer_interval_seconds (float) – See the notes on the Deferred Lost Segment Procedure inside the class documentation. Expected as floating point seconds. Defaults to 10 seconds.
nak_timer_expiration_limit (int) – See the notes on the Deferred Lost Segment Procedure inside the class documentation. Defaults to 2, so the timer may expire two times.

cfdp_version: int = 1

check_limit: int = 2

closure_requested: bool

crc_on_transmission: bool

crc_type: ChecksumType

default_transmission_mode: TransmissionMode

disposition_on_cancellation: bool = False

entity_id: UnsignedByteField

immediate_nak_mode: bool = True

max_file_segment_len: int | None

max_packet_len: int

nak_timer_expiration_limit: int = 2

nak_timer_interval_seconds: float = 10.0

positive_ack_timer_expiration_limit: int = 2

positive_ack_timer_interval_seconds: float = 10.0

class cfdppy.RemoteEntityConfigTable(init_cfgs: Sequence[RemoteEntityConfig] | None = None)

Bases: object

Thin abstraction for a dictionary containing remote configurations with the remote entity ID being used as a key.

add_config(cfg: RemoteEntityConfig) → bool

add_configs(cfgs: Sequence[RemoteEntityConfig]) → None

get_cfg(remote_entity_id: UnsignedByteField) → RemoteEntityConfig | None

class cfdppy.RestrictedFilestore(restricted_path: Path)

Bases: NativeFilestore

Wrapper to restrict filestore access to a specific directory.

calculate_checksum(checksum_type: ChecksumType, file_path: Path, size_to_verify: int, segment_len: int = 4096) → bytes

Calculate checksum of file.

Parameters:

checksum_type – Type of checksum
file_path – Path to file
size_to_verify – Size to check in bytes
segment_len – Length of segments to calculate checksum for

Returns:

checksum as bytes

create_directory(_dir_name: Path) → FilestoreResponseStatusCode: Create directory.

create_file(file: Path) → FilestoreResponseStatusCode: Create file.

delete_file(file: Path) → FilestoreResponseStatusCode: Delete file.

file_exists(path: Path) → bool: Check if file exists.

file_size(file: Path) → int: Get file size.

filename_from_full_path(path: Path) → str | None: Get filename from full path.

is_directory(path: Path) → bool: Check if path is a directory.

list_directory(_dir_name: Path, _file_name: Path, _recursive: bool = False) → FilestoreResponseStatusCode: List directory contents.

read_data(file: Path, offset: int | None, read_len: int | None = None) → bytes: Read data from file.

remove_directory(dir_name: Path, recursive: bool = False) → FilestoreResponseStatusCode: Remove directory.

rename_file(_old_file: Path, _new_file: Path) → FilestoreResponseStatusCode: Rename file.

replace_file(_replaced_file: Path, _source_file: Path) → FilestoreResponseStatusCode: Replace file.

truncate_file(file: Path) → None: Truncate file.

verify_checksum(checksum: int | bytes, checksum_type: ChecksumType, file_path: Path, size_to_verify: int, segment_len: int = 4096) → bool

write_data(file: Path, data: bytes, offset: int | None) → None: Write data to file.

class cfdppy.TransactionId(source_entity_id: UnsignedByteField, transaction_seq_num: UnsignedByteField): Bases: object

class cfdppy.VirtualFilestore

Bases: ABC

Interface for a virtual filestore implementation.

abstract calculate_checksum(checksum_type: ChecksumType, file_path: Path, size_to_verify: int, segment_len: int = 4096) → bytes

Calculate the checksum for a given file.

Raises:

ValueError – Invalid input parameters
FileNotFoundError – File for checksum calculation does not exist

abstract create_directory(_dir_name: Path) → FilestoreResponseStatusCode

abstract create_file(file: Path) → FilestoreResponseStatusCode

abstract delete_file(file: Path) → FilestoreResponseStatusCode

abstract file_exists(path: Path) → bool

Check if a file exists at the given path.

Parameters:: path – Path to check
Returns:: True if the file exists

abstract file_size(file: Path) → int

Get the size of a file.

Parameters:: file – File to get the size of as number of bytes
Returns:: Size of the file in bytes
Raises:: FileNotFoundError – In case the file does not exist

abstract filename_from_full_path(path: Path) → str | None

Get the filename from a full path.

Parameters:: path – Full path
Returns:: Filename

abstract is_directory(path: Path) → bool

Check if a given path is a directory.

Parameters:: path – Path to check
Returns:: True if the path is a directory

abstract list_directory(_dir_name: Path, _file_name: Path, _recursive: bool = False) → FilestoreResponseStatusCode

abstract read_data(file: Path, offset: int | None, read_len: int) → bytes

Read data from a provided Path at a specific offset.

This is not used as part of a filestore request. It is used to read a file, for example to send it.

Parameters:

file – File to read
offset – Offset to read from
read_len – Number of bytes to read

Returns:

The read data

Raises:

PermissionError – In case the file is not readable
FileNotFoundError – In case the file does not exist.

abstract read_from_opened_file(bytes_io: BinaryIO, offset: int, read_len: int) → bytes

Read data from an already opened file object.

Parameters:

bytes_io – File object
offset – Offset to read from
read_len – Number of bytes to read

Returns:

The read data

abstract remove_directory(_dir_name: Path, recursive: bool) → FilestoreResponseStatusCode

abstract rename_file(_old_file: Path, _new_file: Path) → FilestoreResponseStatusCode

abstract replace_file(_replaced_file: Path, _source_file: Path) → FilestoreResponseStatusCode

abstract truncate_file(file: Path) → None

Truncate a file to zero bytes.

Parameters:: file – File to truncate
Raises:: FileNotFoundError – In case the file does not exist

verify_checksum(checksum: bytes, checksum_type: ChecksumType, file_path: Path, size_to_verify: int, segment_len: int = 4096) → bool

abstract write_data(file: Path, data: bytes, offset: int | None) → None

This is not used as part of a filestore request, it is used to build up the received file.

The file needs to exist before writing to it.

Parameters:

file – File to write to
data – Data to write
offset – Offset to write, may be None for no offset

Raises:

PermissionError – In case the file is not writable
FileNotFoundError – In case the file does not exist

cfdppy.get_packet_destination(packet: AbstractFileDirectiveBase | AbstractPduBase) → PacketDestination

This function routes the packets based on PDU type and directive type if applicable.

The routing is based on section 4.5 of the CFDP standard which specifies the PDU forwarding procedure.

NOTE: The standard also specifies a direction flag, which could be used for that purpose as well. However, I prefer the approach here to explicitly check the PDU types and event the ACK PDU content. I think this is more reliable than relying on that bit.

Filestore Module

Contains the Filestore Interface and a Native Filestore implementation.

cfdppy.filestore.HostFilestore: alias of NativeFilestore

class cfdppy.filestore.NativeFilestore

Bases: VirtualFilestore

calculate_checksum(checksum_type: ChecksumType, file_path: Path, size_to_verify: int, segment_len: int = 4096) → bytes

Calculate the checksum for a given file.

Raises:

ValueError – Invalid input parameters
FileNotFoundError – File for checksum calculation does not exist

checksum_type_to_crcmod_str(checksum_type: ChecksumType) → str | None

create_directory(dir_name: Path) → FilestoreResponseStatusCode

create_file(file: Path) → FilestoreResponseStatusCode: Returns CREATE_NOT_ALLOWED if the file already exists

delete_file(file: Path) → FilestoreResponseStatusCode

file_exists(path: Path) → bool

Check if a file exists at the given path.

Parameters:: path – Path to check
Returns:: True if the file exists

file_size(file: Path) → int

Get the size of a file.

Parameters:: file – File to get the size of as number of bytes
Returns:: Size of the file in bytes
Raises:: FileNotFoundError – In case the file does not exist

filename_from_full_path(path: Path) → str | None

Get the filename from a full path.

Parameters:: path – Full path
Returns:: Filename

is_directory(path: Path) → bool

Check if a given path is a directory.

Parameters:: path – Path to check
Returns:: True if the path is a directory

list_directory(dir_name: Path, target_file: Path, recursive: bool = False) → FilestoreResponseStatusCode

List a directory

Parameters:

dir_name – Name of directory to list
target_file – The list will be written into this target file
recursive

Returns:

read_data(file: Path, offset: int | None, read_len: int | None = None) → bytes

Read data from a provided Path at a specific offset.

This is not used as part of a filestore request. It is used to read a file, for example to send it.

Parameters:

file – File to read
offset – Offset to read from
read_len – Number of bytes to read

Returns:

The read data

Raises:

PermissionError – In case the file is not readable
FileNotFoundError – In case the file does not exist.

read_from_opened_file(bytes_io: BinaryIO, offset: int, read_len: int) → bytes

Read data from an already opened file object.

Parameters:

bytes_io – File object
offset – Offset to read from
read_len – Number of bytes to read

Returns:

The read data

remove_directory(dir_name: Path, recursive: bool = False) → FilestoreResponseStatusCode

rename_file(old_file: Path, new_file: Path) → FilestoreResponseStatusCode

replace_file(replaced_file: Path, source_file: Path) → FilestoreResponseStatusCode

truncate_file(file: Path) → None

Truncate a file to zero bytes.

Parameters:: file – File to truncate
Raises:: FileNotFoundError – In case the file does not exist

write_data(file: Path, data: bytes, offset: int | None) → None

Primary function used to perform the CFDP Copy Procedure. This will also create a new file as long as no other file with the same name exists

Returns:
Raises:: FileNotFoundError – File not found

class cfdppy.filestore.VirtualFilestore

Bases: ABC

Interface for a virtual filestore implementation.

abstract calculate_checksum(checksum_type: ChecksumType, file_path: Path, size_to_verify: int, segment_len: int = 4096) → bytes

Calculate the checksum for a given file.

Raises:

ValueError – Invalid input parameters
FileNotFoundError – File for checksum calculation does not exist

abstract create_directory(_dir_name: Path) → FilestoreResponseStatusCode

abstract create_file(file: Path) → FilestoreResponseStatusCode

abstract delete_file(file: Path) → FilestoreResponseStatusCode

abstract file_exists(path: Path) → bool

Check if a file exists at the given path.

Parameters:: path – Path to check
Returns:: True if the file exists

abstract file_size(file: Path) → int

Get the size of a file.

Parameters:: file – File to get the size of as number of bytes
Returns:: Size of the file in bytes
Raises:: FileNotFoundError – In case the file does not exist

abstract filename_from_full_path(path: Path) → str | None

Get the filename from a full path.

Parameters:: path – Full path
Returns:: Filename

abstract is_directory(path: Path) → bool

Check if a given path is a directory.

Parameters:: path – Path to check
Returns:: True if the path is a directory

abstract list_directory(_dir_name: Path, _file_name: Path, _recursive: bool = False) → FilestoreResponseStatusCode

abstract read_data(file: Path, offset: int | None, read_len: int) → bytes

Read data from a provided Path at a specific offset.

This is not used as part of a filestore request. It is used to read a file, for example to send it.

Parameters:

file – File to read
offset – Offset to read from
read_len – Number of bytes to read

Returns:

The read data

Raises:

PermissionError – In case the file is not readable
FileNotFoundError – In case the file does not exist.

abstract read_from_opened_file(bytes_io: BinaryIO, offset: int, read_len: int) → bytes

Read data from an already opened file object.

Parameters:

bytes_io – File object
offset – Offset to read from
read_len – Number of bytes to read

Returns:

The read data

abstract remove_directory(_dir_name: Path, recursive: bool) → FilestoreResponseStatusCode

abstract rename_file(_old_file: Path, _new_file: Path) → FilestoreResponseStatusCode

abstract replace_file(_replaced_file: Path, _source_file: Path) → FilestoreResponseStatusCode

abstract truncate_file(file: Path) → None

Truncate a file to zero bytes.

Parameters:: file – File to truncate
Raises:: FileNotFoundError – In case the file does not exist

verify_checksum(checksum: bytes, checksum_type: ChecksumType, file_path: Path, size_to_verify: int, segment_len: int = 4096) → bool

abstract write_data(file: Path, data: bytes, offset: int | None) → None

This is not used as part of a filestore request, it is used to build up the received file.

The file needs to exist before writing to it.

Parameters:

file – File to write to
data – Data to write
offset – Offset to write, may be None for no offset

Raises:

PermissionError – In case the file is not writable
FileNotFoundError – In case the file does not exist

Management Information Base (MIB) Module

class cfdppy.mib.CheckTimerProvider

Bases: ABC

abstract provide_check_timer(local_entity_id: UnsignedByteField, remote_entity_id: UnsignedByteField, entity_type: EntityType) → Countdown

class cfdppy.mib.DefaultFaultHandlerBase

Bases: ABC

This base class provides a way to implement the fault handling procedures as specified in chapter 4.8 of the CFDP standard.

It is passed into the CFDP handlers as part of the local entity configuration and provides a way to specify custom user error handlers.

It does so by mapping each applicable CFDP ConditionCode to a fault handler which is denoted by the four spacepackets.cfdp.defs.FaultHandlerCode s. This code is used to dispatch to a user-provided callback function:

IGNORE_ERROR -> ignore_cb()

NOTICE_OF_CANCELLATION -> notice_of_cancellation_cb()

NOTICE_OF_SUSPENSION -> notice_of_suspension_cb()

ABANDON_TRANSACTION -> abandon_transaction_cb()

For each error reported by report_fault(), the appropriate fault handler callback will be called. The user provides the callbacks by providing a custom class which implements this base class and all abstract fault handler callbacks. This allows logging of the errors as specified in chapter 4.8.3.

Some note on the provided default settings:

Checksum failures will be ignored by default. This is because for unacknowledged transfers, cancelling the transfer immediately would interfere with the check limit mechanism specified in chapter 4.6.3.3.
Unsupported checksum types will also be ignored by default. Even if the checksum type is not supported the file transfer might still have worked properly.

abstract abandoned_cb(transaction_id: TransactionId, cond: ConditionCode, progress: int) → None

get_fault_handler(condition: ConditionCode) → FaultHandlerCode

abstract ignore_cb(transaction_id: TransactionId, cond: ConditionCode, progress: int) → None

abstract notice_of_cancellation_cb(transaction_id: TransactionId, cond: ConditionCode, progress: int) → None

abstract notice_of_suspension_cb(transaction_id: TransactionId, cond: ConditionCode, progress: int) → None

report_fault(transaction_id: TransactionId, condition: ConditionCode, progress: int) → None

Raises:: ValueError – Invalid condition code which is not applicable for fault handling procedures.

set_handler(condition: ConditionCode, handler: FaultHandlerCode) → None

Raises:: ValueError – Invalid condition code which is not applicable for fault handling procedures.

class cfdppy.mib.EntityType(value)

Bases: IntEnum

An enumeration.

RECEIVING = 1

SENDING = 0

class cfdppy.mib.IndicationConfig(eof_sent_indication_required: 'bool' = True, eof_recv_indication_required: 'bool' = True, file_segment_recvd_indication_required: 'bool' = True, transaction_finished_indication_required: 'bool' = True, suspended_indication_required: 'bool' = True, resumed_indication_required: 'bool' = True)

Bases: object

eof_recv_indication_required: bool = True

eof_sent_indication_required: bool = True

file_segment_recvd_indication_required: bool = True

resumed_indication_required: bool = True

suspended_indication_required: bool = True

transaction_finished_indication_required: bool = True

class cfdppy.mib.LocalEntityConfig(local_entity_id: UnsignedByteField, indication_cfg: IndicationConfig, default_fault_handlers: DefaultFaultHandlerBase)

Bases: object

This models the remote entity configuration information as specified in chapter 8.2 of the CFDP standard.

default_fault_handlers: DefaultFaultHandlerBase

indication_cfg: IndicationConfig

local_entity_id: UnsignedByteField

class cfdppy.mib.RemoteEntityConfig(entity_id: UnsignedByteField, max_file_segment_len: int | None, max_packet_len: int, closure_requested: bool, crc_on_transmission: bool, default_transmission_mode: TransmissionMode, crc_type: ChecksumType, positive_ack_timer_interval_seconds: float = 10.0, positive_ack_timer_expiration_limit: int = 2, check_limit: int = 2, disposition_on_cancellation: bool = False, immediate_nak_mode: bool = True, nak_timer_interval_seconds: float = 10.0, nak_timer_expiration_limit: int = 2, cfdp_version: int = 1)

Bases: object

This models the remote entity configuration information as specified in chapter 8.3 of the CFDP standard.

Some of the fields which were not considered necessary for the Python implementation were omitted. Some other fields which are not contained inside the standard but are considered necessary for the Python implementation are included.

Notes on Positive Acknowledgment Procedures

The positive_ack_timer_interval_seconds and positive_ack_timer_expiration_limit will be used for positive acknowledgment procedures as specified in CFDP chapter 4.7. The sending entity will start the timer for any PDUs where an acknowledgment is required (e.g. EOF PDU). Once the expected ACK response has not been received for that interval, as counter will be incremented and the timer will be reset. Once the counter exceeds the positive_ack_timer_expiration_limit, a Positive ACK Limit Reached fault will be declared.

Notes on Deferred Lost Segment Procedures

This procedure will be active if an EOF (No Error) PDU is received in acknowledged mode. After issuing the NAK sequence which has the whole file scope, a timer will be started. The timer is reset when missing segments or missing metadata is received. The timer will be deactivated if all missing data is received. If the timer expires, a new NAK sequence will be issued and a counter will be incremented, which can lead to a NAK Limit Reached fault being declared.

Parameters:

entity_id (UnsignedByteField) – The ID of the remote entity.
max_packet_len (int) – This determines of all PDUs generated for that remote entity in addition to the max_file_segment_len attribute which also determines the size of file data PDUs.
max_file_segment_len (int | None) – The maximum file segment length which determines the maximum size of file data PDUs in addition to the max_packet_len attribute. If this field is set to None, the maximum file segment length will be derived from the maximum packet length. If this has some value which is smaller than the segment value derived from max_packet_len, this value will be picked.
closure_requested (bool) – If the closure requested field is not supplied as part of the Put Request, it will be determined from this field in the remote configuration.
crc_on_transmission (bool) – If the CRC option is not supplied as part of the Put Request, it will be determined from this field in the remote configuration.
default_transmission_mode (TransmissionMode) – If the transmission mode is not supplied as part of the Put Request, it will be determined from this field in the remote configuration.
disposition_on_cancellation (bool) – Determines whether an incomplete received file is discard on transaction cancellation. Defaults to False.
crc_type (ChecksumType) – Default checksum type used to calculate for all file transmissions to this remote entity.
check_limit (int) – this timer determines the expiry period for incrementing a check counter after an EOF PDU is received for an incomplete file transfer. This allows out-of-order reception of file data PDUs and EOF PDUs. Also see 4.6.3.3 of the CFDP standard. Defaults to 2, so the check limit timer may expire twice.
positive_ack_timer_interval_seconds (float) – See the notes on the Positive Acknowledgment Procedures inside the class documentation. Expected as floating point seconds. Defaults to 10 seconds.
positive_ack_timer_expiration_limit (int) – See the notes on the Positive Acknowledgment Procedures inside the class documentation. Defaults to 2, so the timer may expire twice.
immediate_nak_mode (bool) – Specifies whether a NAK sequence should be issued immediately when a file data gap or lost metadata is detected in the acknowledged mode. Defaults to True.
nak_timer_interval_seconds (float) – See the notes on the Deferred Lost Segment Procedure inside the class documentation. Expected as floating point seconds. Defaults to 10 seconds.
nak_timer_expiration_limit (int) – See the notes on the Deferred Lost Segment Procedure inside the class documentation. Defaults to 2, so the timer may expire two times.

cfdp_version: int = 1

check_limit: int = 2

closure_requested: bool

crc_on_transmission: bool

crc_type: ChecksumType

default_transmission_mode: TransmissionMode

disposition_on_cancellation: bool = False

entity_id: UnsignedByteField

immediate_nak_mode: bool = True

max_file_segment_len: int | None

max_packet_len: int

nak_timer_expiration_limit: int = 2

nak_timer_interval_seconds: float = 10.0

positive_ack_timer_expiration_limit: int = 2

positive_ack_timer_interval_seconds: float = 10.0

class cfdppy.mib.RemoteEntityConfigTable(init_cfgs: Sequence[RemoteEntityConfig] | None = None)

Bases: object

Thin abstraction for a dictionary containing remote configurations with the remote entity ID being used as a key.

add_config(cfg: RemoteEntityConfig) → bool

add_configs(cfgs: Sequence[RemoteEntityConfig]) → None

get_cfg(remote_entity_id: UnsignedByteField) → RemoteEntityConfig | None

Request Module

class cfdppy.request.PutRequest(destination_id: UnsignedByteField, source_file: Path | None, dest_file: Path | None, trans_mode: TransmissionMode | None, closure_requested: bool | None, seg_ctrl: SegmentationControl | None = SegmentationControl.NO_RECORD_BOUNDARIES_PRESERVATION, fault_handler_overrides: list[FaultHandlerOverrideTlv] | None = None, flow_label_tlv: FlowLabelTlv | None = None, msgs_to_user: list[MessageToUserTlv] | None = None, fs_requests: list[FileStoreRequestTlv] | None = None)

Bases: object

This is the base class modelling the CFDP put request.

You can create this class from the simplified tmtccmd.config.defs.CfdpParams class with the generic tmtccmd.config.cfdp.generic_cfdp_params_to_put_request() API and/or all related specific APIs.

closure_requested: bool | None

dest_file: Path | None

destination_id: UnsignedByteField

fault_handler_overrides: list[FaultHandlerOverrideTlv] | None = None

flow_label_tlv: FlowLabelTlv | None = None

fs_requests: list[FileStoreRequestTlv] | None = None

property metadata_only: bool

msgs_to_user: list[MessageToUserTlv] | None = None

seg_ctrl: SegmentationControl | None = 0

source_file: Path | None

trans_mode: TransmissionMode | None

User Module

class cfdppy.user.CfdpUserBase(vfs: VirtualFilestore | None = None)

Bases: ABC

This user base class provides the primary user interface to interact with CFDP handlers. It is also used to pass the Virtual Filestore (VFS) implementation to the CFDP handlers so the filestore operations can be mapped to the underlying filestore.

This class is used by implementing it in a child class and then passing it to the CFDP handler objects. The base class provides default implementation for the user indication primitives specified in the CFDP standard. The user can override these implementations to provide custom indication handlers.

abstract abandoned_indication(transaction_id: TransactionId, cond_code: ConditionCode, progress: int) → None

This is the Fault.Indication as specified in chapter 3.4.15 of the standard.

The user implementation of this function could be used to keep a (failed) transaction history, which might be useful for the positive ACK procedures expected from a receiving CFDP entity.

abstract eof_recv_indication(transaction_id: TransactionId) → None

abstract eof_sent_indication(transaction_id: TransactionId) → None

abstract fault_indication(transaction_id: TransactionId, cond_code: ConditionCode, progress: int) → None

This is the Fault.Indication as specified in chapter 3.4.14 of the standard.

The user implementation of this function could be used to keep a (failed) transaction history, which might be useful for the positive ACK procedures expected from a receiving CFDP entity.

abstract file_segment_recv_indication(params: FileSegmentRecvdParams) → None

abstract metadata_recv_indication(params: MetadataRecvParams) → None

abstract report_indication(transaction_id: TransactionId, status_report: Any) → None

abstract resumed_indication(transaction_id: TransactionId, progress: int) → None

abstract suspended_indication(transaction_id: TransactionId, cond_code: ConditionCode) → None

abstract transaction_finished_indication(params: TransactionFinishedParams) → None

This is the Transaction-Finished.Indication as specified in chapter 3.4.8 of the standard.

The user implementation of this function could be used to keep a (failed) transaction history, which might be useful for the positive ACK procedures expected from a receiving CFDP entity.

abstract transaction_indication(transaction_indication_params: TransactionParams) → None: This indication is used to report the transaction ID to the CFDP user

class cfdppy.user.FileSegmentRecvdParams(transaction_id: TransactionId, offset: int, length: int, segment_metadata: SegmentMetadata | None)

Bases: object

The length of the segment metadata is not supplied as an extra parameter as it can be simply queried with len(segment_metadata)

length: int

offset: int

segment_metadata: SegmentMetadata | None

transaction_id: TransactionId

class cfdppy.user.MetadataRecvParams(transaction_id: 'TransactionId', source_id: 'UnsignedByteField', file_size: 'int | None', source_file_name: 'str | None', dest_file_name: 'str | None', msgs_to_user: 'list[MessageToUserTlv] | None' = None)

Bases: object

dest_file_name: str | None

file_size: int | None

msgs_to_user: list[MessageToUserTlv] | None = None

source_file_name: str | None

source_id: UnsignedByteField

transaction_id: TransactionId

class cfdppy.user.TransactionFinishedParams(transaction_id: 'TransactionId', finished_params: 'FinishedParams', status_report: 'Any | None' = None)

Bases: object

finished_params: FinishedParams

status_report: Any | None = None

transaction_id: TransactionId

class cfdppy.user.TransactionParams(transaction_id: TransactionId, originating_transaction_id: TransactionId | None = None)

Bases: object

Not wholly standard conformant here, but supplying the originating transaction ID makes the implementation of handling with proxy put requests easier.

originating_transaction_id: TransactionId | None = None

transaction_id: TransactionId

Exceptions Module

exception cfdppy.exceptions.BusyError: Bases: Exception

exception cfdppy.exceptions.ChecksumNotImplemented(checksum_type: ChecksumType): Bases: Exception

exception cfdppy.exceptions.FsmNotCalledAfterPacketInsertion: Bases: Exception

exception cfdppy.exceptions.InvalidDestinationId(expected_dest_id: UnsignedByteField, found_dest_id: UnsignedByteField)

Bases: Exception

Invalid destination entity ID. This is not necessarily the receiver of a packet but actually the recipient of a file, or the entity receiving file data and metadata PDUs

exception cfdppy.exceptions.InvalidNakPdu: Bases: Exception

exception cfdppy.exceptions.InvalidPduDirection(expected_dir: Direction, found_dir: Direction): Bases: Exception

exception cfdppy.exceptions.InvalidPduForDestHandler(packet: AbstractFileDirectiveBase | AbstractPduBase): Bases: Exception

exception cfdppy.exceptions.InvalidPduForSourceHandler(packet: AbstractFileDirectiveBase): Bases: Exception

exception cfdppy.exceptions.InvalidSourceId(expected_src_id: UnsignedByteField, found_src_id: UnsignedByteField)

Bases: Exception

Invalid source entity ID. This is not necessarily the sender of a packet but actually the entity that started a transaction, or the entity which is transferring a file

exception cfdppy.exceptions.InvalidTransactionSeqNum(expected: UnsignedByteField, received: UnsignedByteField): Bases: Exception

exception cfdppy.exceptions.NoRemoteEntityConfigFound(entity_id: UnsignedByteField): Bases: Exception

exception cfdppy.exceptions.PduIgnoredForDest(reason: PduIgnoredForDestReason, ignored_packet: AbstractFileDirectiveBase | AbstractPduBase): Bases: Exception

class cfdppy.exceptions.PduIgnoredForDestReason(value)

Bases: IntEnum

An enumeration.

FIRST_PACKET_IN_ACKED_MODE_NOT_METADATA_NOT_EOF_NOT_FD = 2: For the acknowledged mode, the first packet that was received with no metadata received previously was not a File Data PDU or EOF PDU.

FIRST_PACKET_NOT_METADATA_PDU = 0: First packet received was not a metadata PDU for the unacknowledged mode.

INVALID_MODE_FOR_ACKED_MODE_PACKET = 1: The received PDU can only be handled in acknowledged mode.

exception cfdppy.exceptions.PduIgnoredForSource(reason: PduIgnoredForSourceReason, ignored_packet: AbstractFileDirectiveBase): Bases: Exception

class cfdppy.exceptions.PduIgnoredForSourceReason(value)

Bases: IntEnum

An enumeration.

ACK_MODE_PACKET_INVALID_MODE = 0

NOT_WAITING_FOR_ACK = 2

NOT_WAITING_FOR_FINISHED_PDU = 1

exception cfdppy.exceptions.SourceFileDoesNotExist(file: Path): Bases: Exception

exception cfdppy.exceptions.UnretrievedPdusToBeSent: Bases: Exception

CRC Module

cfdppy.crc.calc_modular_checksum(file_path: Path) → bytes: Calculates the modular checksum for a file in one go.

Definitions Module

class cfdppy.defs.CfdpIndication(value)

Bases: Enum

An enumeration.

ABANDONED = 9

EOF = 1

EOF_RECV = 10

FAULT = 8

FILE_SEGMENT_RECV = 4

FINISHED = 2

METADATA = 3

REPORT = 5

RESUMED = 7

SUSPENDED = 6

TRANSACTION = 0

class cfdppy.defs.CfdpRequestType(value)

Bases: Enum

An enumeration.

CANCEL = 2

PUT = 0

REPORT = 1

RESUME = 4

SUSPEND = 3

class cfdppy.defs.CfdpState(value)

Bases: Enum

An enumeration.

BUSY = 1

IDLE = 0

SUSPENDED = 2

exception cfdppy.defs.SequenceNumberOverflow: Bases: Exception