Host-customized fork of https://github.com/tecnovert/basicswap/
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495 lines
16 KiB
495 lines
16 KiB
# Author: Johan Hanssen Seferidis |
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# License: MIT |
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import sys |
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import struct |
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import ssl |
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from base64 import b64encode |
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from hashlib import sha1 |
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import logging |
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from socket import error as SocketError |
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import errno |
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import threading |
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from socketserver import ThreadingMixIn, TCPServer, StreamRequestHandler |
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from .thread import WebsocketServerThread |
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logger = logging.getLogger(__name__) |
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logging.basicConfig() |
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''' |
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+-+-+-+-+-------+-+-------------+-------------------------------+ |
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0 1 2 3 |
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |
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+-+-+-+-+-------+-+-------------+-------------------------------+ |
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|F|R|R|R| opcode|M| Payload len | Extended payload length | |
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|I|S|S|S| (4) |A| (7) | (16/64) | |
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|N|V|V|V| |S| | (if payload len==126/127) | |
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| |1|2|3| |K| | | |
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+-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - + |
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| Extended payload length continued, if payload len == 127 | |
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+ - - - - - - - - - - - - - - - +-------------------------------+ |
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| Payload Data continued ... | |
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+---------------------------------------------------------------+ |
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''' |
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FIN = 0x80 |
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OPCODE = 0x0f |
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MASKED = 0x80 |
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PAYLOAD_LEN = 0x7f |
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PAYLOAD_LEN_EXT16 = 0x7e |
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PAYLOAD_LEN_EXT64 = 0x7f |
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OPCODE_CONTINUATION = 0x0 |
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OPCODE_TEXT = 0x1 |
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OPCODE_BINARY = 0x2 |
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OPCODE_CLOSE_CONN = 0x8 |
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OPCODE_PING = 0x9 |
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OPCODE_PONG = 0xA |
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CLOSE_STATUS_NORMAL = 1000 |
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DEFAULT_CLOSE_REASON = bytes('', encoding='utf-8') |
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class API(): |
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def run_forever(self, threaded=False): |
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return self._run_forever(threaded) |
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def new_client(self, client, server): |
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pass |
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def client_left(self, client, server): |
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pass |
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def message_received(self, client, server, message): |
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pass |
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def set_fn_new_client(self, fn): |
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self.new_client = fn |
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def set_fn_client_left(self, fn): |
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self.client_left = fn |
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def set_fn_message_received(self, fn): |
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self.message_received = fn |
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def send_message(self, client, msg): |
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self._unicast(client, msg) |
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def send_message_to_all(self, msg): |
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self._multicast(msg) |
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def deny_new_connections(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON): |
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self._deny_new_connections(status, reason) |
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def allow_new_connections(self): |
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self._allow_new_connections() |
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def shutdown_gracefully(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON): |
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self._shutdown_gracefully(status, reason) |
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def shutdown_abruptly(self): |
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self._shutdown_abruptly() |
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def disconnect_clients_gracefully(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON): |
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self._disconnect_clients_gracefully(status, reason) |
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def disconnect_clients_abruptly(self): |
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self._disconnect_clients_abruptly() |
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class WebsocketServer(ThreadingMixIn, TCPServer, API): |
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""" |
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A websocket server waiting for clients to connect. |
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Args: |
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port(int): Port to bind to |
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host(str): Hostname or IP to listen for connections. By default 127.0.0.1 |
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is being used. To accept connections from any client, you should use |
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0.0.0.0. |
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loglevel: Logging level from logging module to use for logging. By default |
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warnings and errors are being logged. |
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Properties: |
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clients(list): A list of connected clients. A client is a dictionary |
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like below. |
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{ |
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'id' : id, |
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'handler' : handler, |
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'address' : (addr, port) |
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} |
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""" |
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allow_reuse_address = True |
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daemon_threads = True # comment to keep threads alive until finished |
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def __init__(self, host='127.0.0.1', port=0, loglevel=logging.WARNING, key=None, cert=None): |
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logger.setLevel(loglevel) |
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TCPServer.__init__(self, (host, port), WebSocketHandler) |
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self.host = host |
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self.port = self.socket.getsockname()[1] |
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self.url = f'ws://{self.host}:{self.port}/' |
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self.key = key |
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self.cert = cert |
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self.clients = [] |
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self.id_counter = 0 |
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self.thread = None |
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self._deny_clients = False |
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def _run_forever(self, threaded): |
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cls_name = self.__class__.__name__ |
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try: |
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logger.info("Listening on port %d for clients.." % self.port) |
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if threaded: |
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self.daemon = True |
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self.thread = WebsocketServerThread(target=super().serve_forever, daemon=True, logger=logger) |
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if sys.version_info[0] > 3 or (sys.version_info[0] == 3 and sys.version_info[1] >= 10): |
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logger.info(f"Starting {cls_name} on thread {self.thread.name}.") |
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else: |
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logger.info(f"Starting {cls_name} on thread {self.thread.getName()}.") |
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self.thread.start() |
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else: |
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self.thread = threading.current_thread() |
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logger.info(f"Starting {cls_name} on main thread.") |
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super().serve_forever() |
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except KeyboardInterrupt: |
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self.server_close() |
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logger.info("Server terminated.") |
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except Exception as e: |
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logger.error(str(e), exc_info=True) |
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sys.exit(1) |
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def _message_received_(self, handler, msg): |
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self.message_received(self.handler_to_client(handler), self, msg) |
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def _ping_received_(self, handler, msg): |
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handler.send_pong(msg) |
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def _pong_received_(self, handler, msg): |
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pass |
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def _new_client_(self, handler): |
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if self._deny_clients: |
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status = self._deny_clients["status"] |
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reason = self._deny_clients["reason"] |
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handler.send_close(status, reason) |
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self._terminate_client_handler(handler) |
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return |
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self.id_counter += 1 |
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client = { |
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'id': self.id_counter, |
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'handler': handler, |
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'address': handler.client_address |
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} |
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self.clients.append(client) |
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self.new_client(client, self) |
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def _client_left_(self, handler): |
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client = self.handler_to_client(handler) |
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self.client_left(client, self) |
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if client in self.clients: |
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self.clients.remove(client) |
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def _unicast(self, receiver_client, msg): |
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receiver_client['handler'].send_message(msg) |
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def _multicast(self, msg): |
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for client in self.clients: |
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self._unicast(client, msg) |
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def handler_to_client(self, handler): |
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for client in self.clients: |
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if client['handler'] == handler: |
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return client |
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def _terminate_client_handler(self, handler): |
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handler.keep_alive = False |
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handler.finish() |
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handler.connection.close() |
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def _terminate_client_handlers(self): |
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""" |
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Ensures request handler for each client is terminated correctly |
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""" |
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for client in self.clients: |
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self._terminate_client_handler(client["handler"]) |
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def _shutdown_gracefully(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON): |
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""" |
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Send a CLOSE handshake to all connected clients before terminating server |
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""" |
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self.keep_alive = False |
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self._disconnect_clients_gracefully(status, reason) |
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self.server_close() |
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self.shutdown() |
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def _shutdown_abruptly(self): |
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""" |
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Terminate server without sending a CLOSE handshake |
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""" |
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self.keep_alive = False |
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self._disconnect_clients_abruptly() |
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self.server_close() |
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self.shutdown() |
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def _disconnect_clients_gracefully(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON): |
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""" |
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Terminate clients gracefully without shutting down the server |
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""" |
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for client in self.clients: |
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client["handler"].send_close(status, reason) |
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self._terminate_client_handlers() |
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def _disconnect_clients_abruptly(self): |
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""" |
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Terminate clients abruptly (no CLOSE handshake) without shutting down the server |
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""" |
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self._terminate_client_handlers() |
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def _deny_new_connections(self, status, reason): |
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self._deny_clients = { |
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"status": status, |
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"reason": reason, |
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} |
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def _allow_new_connections(self): |
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self._deny_clients = False |
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class WebSocketHandler(StreamRequestHandler): |
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def __init__(self, socket, addr, server): |
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self.server = server |
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self.timeout = 1000 # Must set a timeout or rfile.read timesout in the tests |
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assert not hasattr(self, "_send_lock"), "_send_lock already exists" |
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self._send_lock = threading.Lock() |
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if server.key and server.cert: |
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try: |
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socket = ssl.wrap_socket(socket, server_side=True, certfile=server.cert, keyfile=server.key) |
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except: # Not sure which exception it throws if the key/cert isn't found |
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logger.warning("SSL not available (are the paths {} and {} correct for the key and cert?)".format(server.key, server.cert)) |
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StreamRequestHandler.__init__(self, socket, addr, server) |
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def setup(self): |
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StreamRequestHandler.setup(self) |
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self.keep_alive = True |
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self.handshake_done = False |
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self.valid_client = False |
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def handle(self): |
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while self.keep_alive: |
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if not self.handshake_done: |
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self.handshake() |
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elif self.valid_client: |
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self.read_next_message() |
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def read_bytes(self, num): |
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return self.rfile.read(num) |
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def read_next_message(self): |
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try: |
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b1, b2 = self.read_bytes(2) |
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except TimeoutError: |
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return |
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except SocketError as e: # to be replaced with ConnectionResetError for py3 |
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if e.errno == errno.ECONNRESET: |
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logger.info("Client closed connection.") |
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self.keep_alive = 0 |
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return |
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b1, b2 = 0, 0 |
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except ValueError as e: |
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b1, b2 = 0, 0 |
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fin = b1 & FIN |
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opcode = b1 & OPCODE |
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masked = b2 & MASKED |
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payload_length = b2 & PAYLOAD_LEN |
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if opcode == OPCODE_CLOSE_CONN: |
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logger.info("Client asked to close connection.") |
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self.keep_alive = 0 |
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return |
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if not masked: |
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logger.warning("Client must always be masked.") |
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self.keep_alive = 0 |
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return |
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if opcode == OPCODE_CONTINUATION: |
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logger.warning("Continuation frames are not supported.") |
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return |
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elif opcode == OPCODE_BINARY: |
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logger.warning("Binary frames are not supported.") |
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return |
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elif opcode == OPCODE_TEXT: |
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opcode_handler = self.server._message_received_ |
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elif opcode == OPCODE_PING: |
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opcode_handler = self.server._ping_received_ |
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elif opcode == OPCODE_PONG: |
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opcode_handler = self.server._pong_received_ |
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else: |
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logger.warning("Unknown opcode %#x." % opcode) |
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self.keep_alive = 0 |
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return |
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if payload_length == 126: |
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payload_length = struct.unpack(">H", self.rfile.read(2))[0] |
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elif payload_length == 127: |
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payload_length = struct.unpack(">Q", self.rfile.read(8))[0] |
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masks = self.read_bytes(4) |
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message_bytes = bytearray() |
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for message_byte in self.read_bytes(payload_length): |
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message_byte ^= masks[len(message_bytes) % 4] |
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message_bytes.append(message_byte) |
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opcode_handler(self, message_bytes.decode('utf8')) |
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def send_message(self, message): |
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self.send_text(message) |
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def send_pong(self, message): |
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self.send_text(message, OPCODE_PONG) |
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def send_close(self, status=CLOSE_STATUS_NORMAL, reason=DEFAULT_CLOSE_REASON): |
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""" |
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Send CLOSE to client |
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Args: |
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status: Status as defined in https://datatracker.ietf.org/doc/html/rfc6455#section-7.4.1 |
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reason: Text with reason of closing the connection |
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""" |
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if status < CLOSE_STATUS_NORMAL or status > 1015: |
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raise Exception(f"CLOSE status must be between 1000 and 1015, got {status}") |
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header = bytearray() |
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payload = struct.pack('!H', status) + reason |
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payload_length = len(payload) |
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assert payload_length <= 125, "We only support short closing reasons at the moment" |
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# Send CLOSE with status & reason |
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header.append(FIN | OPCODE_CLOSE_CONN) |
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header.append(payload_length) |
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with self._send_lock: |
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self.request.send(header + payload) |
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def send_text(self, message, opcode=OPCODE_TEXT): |
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""" |
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Important: Fragmented(=continuation) messages are not supported since |
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their usage cases are limited - when we don't know the payload length. |
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""" |
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# Validate message |
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if isinstance(message, bytes): |
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message = try_decode_UTF8(message) # this is slower but ensures we have UTF-8 |
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if not message: |
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logger.warning("Can\'t send message, message is not valid UTF-8") |
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return False |
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elif not isinstance(message, str): |
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logger.warning('Can\'t send message, message has to be a string or bytes. Got %s' % type(message)) |
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return False |
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header = bytearray() |
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payload = encode_to_UTF8(message) |
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payload_length = len(payload) |
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# Normal payload |
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if payload_length <= 125: |
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header.append(FIN | opcode) |
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header.append(payload_length) |
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# Extended payload |
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elif payload_length >= 126 and payload_length <= 65535: |
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header.append(FIN | opcode) |
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header.append(PAYLOAD_LEN_EXT16) |
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header.extend(struct.pack(">H", payload_length)) |
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# Huge extended payload |
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elif payload_length < 18446744073709551616: |
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header.append(FIN | opcode) |
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header.append(PAYLOAD_LEN_EXT64) |
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header.extend(struct.pack(">Q", payload_length)) |
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else: |
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raise Exception("Message is too big. Consider breaking it into chunks.") |
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return |
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with self._send_lock: |
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self.request.send(header + payload) |
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def read_http_headers(self): |
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headers = {} |
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# first line should be HTTP GET |
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http_get = self.rfile.readline().decode().strip() |
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assert http_get.upper().startswith('GET') |
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# remaining should be headers |
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while True: |
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header = self.rfile.readline().decode().strip() |
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if not header: |
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break |
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head, value = header.split(':', 1) |
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headers[head.lower().strip()] = value.strip() |
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return headers |
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def handshake(self): |
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headers = self.read_http_headers() |
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try: |
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assert headers['upgrade'].lower() == 'websocket' |
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except AssertionError: |
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self.keep_alive = False |
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return |
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try: |
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key = headers['sec-websocket-key'] |
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except KeyError: |
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logger.warning("Client tried to connect but was missing a key") |
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self.keep_alive = False |
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return |
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response = self.make_handshake_response(key) |
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with self._send_lock: |
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self.handshake_done = self.request.send(response.encode()) |
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self.valid_client = True |
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self.server._new_client_(self) |
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@classmethod |
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def make_handshake_response(cls, key): |
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return \ |
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'HTTP/1.1 101 Switching Protocols\r\n'\ |
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'Upgrade: websocket\r\n' \ |
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'Connection: Upgrade\r\n' \ |
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'Sec-WebSocket-Accept: %s\r\n' \ |
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'\r\n' % cls.calculate_response_key(key) |
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@classmethod |
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def calculate_response_key(cls, key): |
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GUID = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11' |
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hash = sha1(key.encode() + GUID.encode()) |
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response_key = b64encode(hash.digest()).strip() |
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return response_key.decode('ASCII') |
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def finish(self): |
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self.server._client_left_(self) |
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def encode_to_UTF8(data): |
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try: |
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return data.encode('UTF-8') |
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except UnicodeEncodeError as e: |
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logger.error("Could not encode data to UTF-8 -- %s" % e) |
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return False |
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except Exception as e: |
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raise(e) |
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return False |
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def try_decode_UTF8(data): |
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try: |
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return data.decode('utf-8') |
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except UnicodeDecodeError: |
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return False |
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except Exception as e: |
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raise(e)
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