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9dc0cbaece
* Add retries to query(), defaults to 3 + add tests * Catch also json decoding errors for retries * add missing exceptions file, fix old protocol tests
129 lines
4.3 KiB
Python
Executable File
129 lines
4.3 KiB
Python
Executable File
"""Implementation of the TP-Link Smart Home Protocol.
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Encryption/Decryption methods based on the works of
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Lubomir Stroetmann and Tobias Esser
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https://www.softscheck.com/en/reverse-engineering-tp-link-hs110/
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https://github.com/softScheck/tplink-smartplug/
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which are licensed under the Apache License, Version 2.0
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http://www.apache.org/licenses/LICENSE-2.0
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"""
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import asyncio
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import json
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import logging
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import struct
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from pprint import pformat as pf
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from typing import Dict, Union
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from .exceptions import SmartDeviceException
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_LOGGER = logging.getLogger(__name__)
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class TPLinkSmartHomeProtocol:
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"""Implementation of the TP-Link Smart Home protocol."""
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INITIALIZATION_VECTOR = 171
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DEFAULT_PORT = 9999
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DEFAULT_TIMEOUT = 5
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@staticmethod
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async def query(host: str, request: Union[str, Dict], retry_count: int = 3) -> Dict:
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"""Request information from a TP-Link SmartHome Device.
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:param str host: host name or ip address of the device
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:param request: command to send to the device (can be either dict or
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json string)
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:param retry_count: how many retries to do in case of failure
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:return: response dict
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"""
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if isinstance(request, dict):
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request = json.dumps(request)
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timeout = TPLinkSmartHomeProtocol.DEFAULT_TIMEOUT
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writer = None
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for retry in range(retry_count + 1):
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try:
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task = asyncio.open_connection(
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host, TPLinkSmartHomeProtocol.DEFAULT_PORT
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)
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reader, writer = await asyncio.wait_for(task, timeout=timeout)
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_LOGGER.debug("> (%i) %s", len(request), request)
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writer.write(TPLinkSmartHomeProtocol.encrypt(request))
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await writer.drain()
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buffer = bytes()
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# Some devices send responses with a length header of 0 and
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# terminate with a zero size chunk. Others send the length and
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# will hang if we attempt to read more data.
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length = -1
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while True:
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chunk = await reader.read(4096)
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if length == -1:
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length = struct.unpack(">I", chunk[0:4])[0]
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buffer += chunk
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if (length > 0 and len(buffer) >= length + 4) or not chunk:
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break
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response = TPLinkSmartHomeProtocol.decrypt(buffer[4:])
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json_payload = json.loads(response)
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_LOGGER.debug("< (%i) %s", len(response), pf(json_payload))
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return json_payload
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except Exception as ex:
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if retry >= retry_count:
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_LOGGER.debug("Giving up after %s retries", retry)
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raise SmartDeviceException(
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"Unable to query the device: %s" % ex
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) from ex
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_LOGGER.debug("Unable to query the device, retrying: %s", ex)
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finally:
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if writer:
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writer.close()
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await writer.wait_closed()
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# make mypy happy, this should never be reached..
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raise SmartDeviceException("Query reached somehow to unreachable")
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@staticmethod
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def encrypt(request: str) -> bytes:
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"""Encrypt a request for a TP-Link Smart Home Device.
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:param request: plaintext request data
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:return: ciphertext to be send over wire, in bytes
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"""
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key = TPLinkSmartHomeProtocol.INITIALIZATION_VECTOR
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plainbytes = request.encode()
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buffer = bytearray(struct.pack(">I", len(plainbytes)))
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for plainbyte in plainbytes:
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cipherbyte = key ^ plainbyte
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key = cipherbyte
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buffer.append(cipherbyte)
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return bytes(buffer)
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@staticmethod
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def decrypt(ciphertext: bytes) -> str:
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"""Decrypt a response of a TP-Link Smart Home Device.
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:param ciphertext: encrypted response data
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:return: plaintext response
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"""
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key = TPLinkSmartHomeProtocol.INITIALIZATION_VECTOR
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buffer = []
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for cipherbyte in ciphertext:
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plainbyte = key ^ cipherbyte
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key = cipherbyte
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buffer.append(plainbyte)
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plaintext = bytes(buffer)
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return plaintext.decode()
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