vinegar.tftp.protocol

TFTP protocol definitions and utility functions.

vinegar.tftp.protocol.DEFAULT_BLOCK_SIZE = 512

Default size of a transfer block in bytes. This block size is used if the client does not request a specific block size.

class vinegar.tftp.protocol.ErrorCode

Code identifying the type of of error in a TFTP error packet.

ACCESS_VIOLATION = 2

Access to the requested file has been forbidden.

DISK_FULL = 3

The disk is full (for write requests).

FILE_ALREADY_EXISTS = 6

File does already exist and is not overwritten (for write requests).

FILE_NOT_FOUND = 1

Requested file could not be found.

ILLEGAL_OPERATION = 4

The requested operation is not allowed in this context by the protocol specification.

NOT_DEFINED = 0

Error does not fall into any of the other well-defined categories.

NO_SUCH_USER = 7

The specified user is not known by this server (for write requests using the mail mode).

UNKNOWN_TRANSFER_ID = 5

The packet was received from an unexpected source address or port.

to_bytes() → bytes

Return a byte buffer that contains the two bytes that represent this error code.

vinegar.tftp.protocol.MAX_BLOCK_NUMBER = 65535

Highest possible block number. Beyond this number, the block counter has to wrap back to zero or one.

vinegar.tftp.protocol.MAX_BLOCK_SIZE = 65464

Maximum transfer block size that may be requested by a client.

vinegar.tftp.protocol.MAX_REQUEST_PACKET_SIZE = 512

Maximum size of a request packet in bytes. A TFTP request must never exceed that size.

vinegar.tftp.protocol.MAX_TIMEOUT = 255

Maximum timeout interval that is alloed by RFC 2349.

vinegar.tftp.protocol.MIN_BLOCK_SIZE = 8

Minimum block size that may be requested by a client.

vinegar.tftp.protocol.MIN_TIMEOUT = 1

Minimum timeout interval that is allowed by RFC 2349.

vinegar.tftp.protocol.OPTION_BLOCK_SIZE = 'blksize'

Name of the block-size option.

vinegar.tftp.protocol.OPTION_TIMEOUT = 'timeout'

Name of the timeout-interval option.

vinegar.tftp.protocol.OPTION_TRANSFER_SIZE = 'tsize'

Name of the transfer-size option.

class vinegar.tftp.protocol.Opcode

Code identifying the type of of a TFTP packet.

ACK = 4

Acknowledgement of a received DATA packet.

DATA = 3

Data transfer from the server to the client (read) or from the client to the server (write).

ERROR = 5

Error message.

OPTIONS_ACK = 6

Acknowledgement of supported options (send from the server to the client as the first response to a request specifying supported options).

READ_REQUEST = 1

Client request for reading a file.

WRITE_REQUEST = 2

Client request for writing a file.

to_bytes() → bytes

Return a byte buffer that contains the two bytes that represent this opcode.

class vinegar.tftp.protocol.TransferMode

Transfer mode that can be requested by a client.

MAIL = 3

Deprecated mail transfer mode. This mode could be used by clients to write a file that would then be sent to a user by e-mail.

NETASCII = 1

Netascii transfer mode. In this mode, all line breaks are converted to CR LF before sending them over the wire.

OCTET = 2

Binary transfer mode. In this mode, bytes are sent without any conversion.

to_str() → str

Return a string representing this transfer mode.

vinegar.tftp.protocol.data_packet(block_number: int, data: bytes) → bytes

Create a data packet using the given block number and data.

Parameters

• block_number – consecutive number of the block being sent.

• data – data to be transferred in this block.

Returns

byte sequence representing a data packet.

vinegar.tftp.protocol.decode_ack(data: bytes) → int

Decode a packet that represents an ACK. Throws an exception if the packet does not represent a valid ACK.

The return value is the acknowledged block number.

Parameters

data – data representing the packet.

Returns

acknowledged block number specified by the packet.

vinegar.tftp.protocol.decode_error(data: bytes) → Tuple[vinegar.tftp.protocol.ErrorCode, str]

Decode a packet that represents an error message. This function does not raise an exception of the data does not represent a valid error message. Instead, it tries to reconstruct as much of it as possible.

The returned tuple contains the error code and the error message. If the error code cannot be decoded, None is returned instead. If the error message cannot be decoded, an empty string is returned instead.

Parameters

data – data representing the packet.

Returns

tuple where the first element is the error code and the second element is the error message sent by the peer.

vinegar.tftp.protocol.decode_read_request(data: bytes) → Tuple[str, vinegar.tftp.protocol.TransferMode, Mapping[str, str]]

Decode a packet that represents a read request. Throws an exception if the packet does not represent a valid read request.

The returned tuple contains the requested filename, the requested transfer mode and the specified options.

Parameters

data – data representing the packet.

Returns

tuple where the first element is the requested filename, the second element is the requested transfer-mode, and the thir element are additional options that have been specified by the client.

vinegar.tftp.protocol.error_packet(error_code: vinegar.tftp.protocol.ErrorCode, error_message: str = '') → bytes

Create an error packet using the given error code and message string.

Parameters

• error_code – code that indicates the kind of error.

• error_message – optional error message.

Returns

sequence of bytes representing the error packet.

vinegar.tftp.protocol.options_ack_packet(options: Mapping[str, str]) → bytes

Create a packet acknowledging options.

Parameters

options – options that shall be acknowledged. Options are mappings from option name strings to value strings. Option names must be non-empty strings and there must be at least one option present.

Returns

sequence of bytes representing the options acknowledgement packet.