170 lines
6 KiB
Python
170 lines
6 KiB
Python
# JTFTP - Python/AsyncIO TFTP Server
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# Copyright (C) 2022 Jeffrey C. Ollie
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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import asyncio
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import functools
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import logging
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from jtftp.datagram import Datagram
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from jtftp.datagram import ERRORDatagram
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from jtftp.datagram import RRQDatagram
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from jtftp.datagram import TFTPError
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from jtftp.datagram import TFTPMode
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from jtftp.datagram import WRQDatagram
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from jtftp.datagram import datagram_factory
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from jtftp.errors import OptionsDecodeError
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from jtftp.errors import PayloadDecodeError
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from jtftp.filesystem import FileMode
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from jtftp.filesystem import FilesystemProtocol
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from jtftp.log import handle_task_result
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from jtftp.netascii import NetAscii
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from jtftp.netascii import NetAsciiReceiverProxy
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from jtftp.netascii import NetAsciiSenderProxy
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from jtftp.protocol.remote_origin_read import remote_origin_read_protocol
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from jtftp.protocol.remote_origin_write import remote_origin_write_protocol
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logger = logging.getLogger(__name__)
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class TftpServerProtocol(asyncio.DatagramProtocol):
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filesystem: FilesystemProtocol
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loop: asyncio.AbstractEventLoop
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def __init__(
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self, filesystem: FilesystemProtocol, loop: asyncio.AbstractEventLoop = None
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):
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super().__init__()
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self.filesystem = filesystem
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if loop is None:
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loop = asyncio.get_event_loop()
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self.loop = loop
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def connection_made(self, transport: asyncio.transports.DatagramTransport) -> None:
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logger.debug(f"listening on made {transport.get_extra_info('sockname')[:2]}")
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self.transport = transport
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async def send(self, datagram: Datagram, tid: tuple[str, int]) -> None:
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self.transport.sendto(datagram.to_wire(), tid)
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def datagram_received(
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self, data: bytes, addr: tuple[str, int] | tuple[str, int, int, int]
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) -> None:
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logger.debug(f"datagram received: {data!r} {addr!r}")
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tid = addr[:2]
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task = self.loop.create_task(self._datagram_received(data, tid))
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task.add_done_callback(handle_task_result)
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async def _datagram_received(self, data: bytes, tid: tuple[str, int]) -> None:
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try:
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datagram = datagram_factory(data)
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except OptionsDecodeError as e:
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await self.send(
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ERRORDatagram.from_code(TFTPError.ILLEGAL_OPERATION, str(e)),
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tid,
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)
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return
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except PayloadDecodeError as e:
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await self.send(
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ERRORDatagram.from_code(TFTPError.ILLEGAL_OPERATION, str(e)),
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tid,
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)
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return
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if not isinstance(datagram, (RRQDatagram, WRQDatagram)):
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logger.warning(
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f"Datagram with unexpected opcode {datagram.opcode} was received without establishing the session. Ignoring."
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)
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return
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if datagram.mode == TFTPMode.MAIL:
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errmsg = f"Usupported transfer mode '{datagram.mode.decode('ascii')}'"
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await self.send(
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ERRORDatagram.from_code(TFTPError.ILLEGAL_OPERATION, errmsg),
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tid,
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)
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return
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match datagram:
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case WRQDatagram():
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try:
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file = await self.filesystem.open(
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datagram.filename, FileMode.BINARY_WRITE
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)
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if datagram.mode != TFTPMode.OCTET:
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file = NetAsciiReceiverProxy(file)
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protocol = functools.partial(
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remote_origin_write_protocol,
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file=file,
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options=datagram.options,
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loop=self.loop,
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)
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except PermissionError:
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await self.send(
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ERRORDatagram.from_code(TFTPError.ACCESS_VIOLATION),
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tid,
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)
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return
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except FileExistsError:
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await self.send(
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ERRORDatagram.from_code(TFTPError.FILE_NOT_FOUND),
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tid,
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)
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return
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case RRQDatagram():
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try:
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file = await self.filesystem.open(
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datagram.filename, FileMode.BINARY_READ
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)
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if datagram.mode != TFTPMode.OCTET:
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file = NetAsciiSenderProxy(file)
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protocol = functools.partial(
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remote_origin_read_protocol,
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file=file,
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options=datagram.options,
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loop=self.loop,
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)
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except PermissionError:
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await self.send(
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ERRORDatagram.from_code(TFTPError.ACCESS_VIOLATION),
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tid,
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)
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return
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except FileNotFoundError:
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await self.send(
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ERRORDatagram.from_code(TFTPError.FILE_NOT_FOUND),
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tid,
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)
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return
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await self.loop.create_datagram_endpoint(
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protocol,
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local_addr=None,
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remote_addr=tid,
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)
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def tftp_server_protocol_factory(
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*, filesystem: FilesystemProtocol, loop: asyncio.AbstractEventLoop = None
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) -> TftpServerProtocol:
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return TftpServerProtocol(filesystem=filesystem, loop=loop)
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