# This file is based on TLSharp # https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/Network/MtProtoSender.cs import re import zlib import pyaes from time import sleep from utils.binary_writer import BinaryWriter from utils.binary_reader import BinaryReader from tl.types.msgs_ack import MsgsAck import utils.helpers as helpers class MtProtoSender: """MTProto Mobile Protocol sender (https://core.telegram.org/mtproto/description)""" def __init__(self, transport, session): self.transport = transport self.session = session self.need_confirmation = [] # Message IDs that need confirmation def generate_sequence(self, confirmed): """Generates the next sequence number, based on whether it was confirmed yet or not""" if confirmed: result = self.session.sequence * 2 + 1 self.session.sequence += 1 return result else: return self.session.sequence * 2 # region Send and receive # TODO In TLSharp, this was async. Should this be? def send(self, request): """Sends the specified MTProtoRequest, previously sending any message which needed confirmation""" # First check if any message needs confirmation, if this is the case, send an "AckRequest" if self.need_confirmation: msgs_ack = MsgsAck(self.need_confirmation) with BinaryWriter() as writer: msgs_ack.on_send(writer) self.send_packet(writer.get_bytes(), msgs_ack) del self.need_confirmation[:] # Then send our packed request with BinaryWriter() as writer: request.on_send(writer) self.send_packet(writer.get_bytes(), request) # And update the saved session self.session.save() def receive(self, request): """Receives the specified MTProtoRequest ("fills in it" the received data)""" while not request.confirm_received: message, remote_msg_id, remote_sequence = self.decode_msg(self.transport.receive().body) with BinaryReader(message) as reader: self.process_msg(remote_msg_id, remote_sequence, reader, request) # endregion # region Low level processing def send_packet(self, packet, request): """Sends the given packet bytes with the additional information of the original request""" request.msg_id = self.session.get_new_msg_id() # First calculate the ciphered bit with BinaryWriter() as writer: writer.write_long(self.session.salt, signed=False) writer.write_long(self.session.id, signed=False) writer.write_long(request.msg_id) writer.write_int(self.generate_sequence(request.confirmed)) writer.write_int(len(packet)) writer.write(packet) msg_key = helpers.calc_msg_key(writer.get_bytes()) key, iv = helpers.calc_key(self.session.auth_key.data, msg_key, True) aes = pyaes.AESModeOfOperationCFB(key, iv, 16) cipher_text = aes.encrypt(writer.get_bytes()) # And then finally send the packet with BinaryWriter() as writer: writer.write_long(self.session.auth_key.id, signed=False) writer.write(msg_key) writer.write(cipher_text) self.transport.send(writer.get_bytes()) def decode_msg(self, body): """Decodes an received encrypted message body bytes""" message = None remote_msg_id = None remote_sequence = None with BinaryReader(body) as reader: if len(body) < 8: raise BufferError("Can't decode packet") # TODO Check for both auth key ID and msg_key correctness remote_auth_key_id = reader.read_long() msg_key = reader.read(16) key, iv = helpers.calc_key(self.session.auth_key.data, msg_key, False) aes = pyaes.AESModeOfOperationCFB(key, iv, 16) plain_text = aes.decrypt(reader.read(len(body) - reader.tell_position())) with BinaryReader(plain_text) as plain_text_reader: remote_salt = plain_text_reader.read_long() remote_session_id = plain_text_reader.read_long() remote_msg_id = plain_text_reader.read_long() remote_sequence = plain_text_reader.read_int() msg_len = plain_text_reader.read_int() message = plain_text_reader.read(msg_len) return message, remote_msg_id, remote_sequence def process_msg(self, msg_id, sequence, reader, request): """Processes and handles a Telegram message""" # TODO Check salt, session_id and sequence_number self.need_confirmation.append(msg_id) code = reader.read_int(signed=False) reader.seek(-4) if code == 0x73f1f8dc: # Container return self.handle_container(msg_id, sequence, reader, request) if code == 0x7abe77ec: # Ping return self.handle_ping(msg_id, sequence, reader) if code == 0x347773c5: # pong return self.handle_pong(msg_id, sequence, reader) if code == 0xae500895: # future_salts return self.handle_future_salts(msg_id, sequence, reader) if code == 0x9ec20908: # new_session_created return self.handle_new_session_created(msg_id, sequence, reader) if code == 0x62d6b459: # msgs_ack return self.handle_msgs_ack(msg_id, sequence, reader) if code == 0xedab447b: # bad_server_salt return self.handle_bad_server_salt(msg_id, sequence, reader, request) if code == 0xa7eff811: # bad_msg_notification return self.handle_bad_msg_notification(msg_id, sequence, reader) if code == 0x276d3ec6: # msg_detailed_info return self.hangle_msg_detailed_info(msg_id, sequence, reader) if code == 0xf35c6d01: # rpc_result return self.handle_rpc_result(msg_id, sequence, reader, request) if code == 0x3072cfa1: # gzip_packed return self.handle_gzip_packed(msg_id, sequence, reader, request) if (code == 0xe317af7e or code == 0xd3f45784 or code == 0x2b2fbd4e or code == 0x78d4dec1 or code == 0x725b04c3 or code == 0x74ae4240): return self.handle_update(msg_id, sequence, reader) print('Unknown message: {}'.format(hex(msg_id))) return False # endregion # region Message handling def handle_update(self, msg_id, sequence, reader): return False def handle_container(self, msg_id, sequence, reader, request): code = reader.read_int(signed=False) size = reader.read_int() for _ in range(size): inner_msg_id = reader.read_long(signed=False) inner_sequence = reader.read_int() inner_length = reader.read_int() begin_position = reader.tell_position() try: if not self.process_msg(inner_msg_id, sequence, reader, request): reader.set_position(begin_position + inner_length) except: reader.set_position(begin_position + inner_length) return False def handle_ping(self, msg_id, sequence, reader): return False def handle_pong(self, msg_id, sequence, reader): return False def handle_future_salts(self, msg_id, sequence, reader): code = reader.read_int(signed=False) request_id = reader.read_long(signed=False) reader.seek(-12) raise NotImplementedError("Handle future server salts function isn't implemented.") def handle_new_session_created(self, msg_id, sequence, reader): return False def handle_msgs_ack(self, msg_id, sequence, reader): return False def handle_bad_server_salt(self, msg_id, sequence, reader, mtproto_request): code = reader.read_int(signed=False) bad_msg_id = reader.read_long(signed=False) bad_msg_seq_no = reader.read_int() error_code = reader.read_int() new_salt = reader.read_long(signed=False) self.session.salt = new_salt # Resend self.send(mtproto_request) return True def handle_bad_msg_notification(self, msg_id, sequence, reader): code = reader.read_int(signed=False) request_id = reader.read_long(signed=False) request_sequence = reader.read_int() error_code = reader.read_int() if error_code == 16: raise RuntimeError("msg_id too low (most likely, client time is wrong it would be worthwhile to " "synchronize it using msg_id notifications and re-send the original message " "with the “correct” msg_id or wrap it in a container with a new msg_id if the " "original message had waited too long on the client to be transmitted)") if error_code == 17: raise RuntimeError("msg_id too high (similar to the previous case, the client time has to be " "synchronized, and the message re-sent with the correct msg_id)") if error_code == 18: raise RuntimeError("Incorrect two lower order msg_id bits (the server expects client message msg_id " "to be divisible by 4)") if error_code == 19: raise RuntimeError("Container msg_id is the same as msg_id of a previously received message " "(this must never happen)") if error_code == 20: raise RuntimeError("Message too old, and it cannot be verified whether the server has received a " "message with this msg_id or not") if error_code == 32: raise RuntimeError("msg_seqno too low (the server has already received a message with a lower " "msg_id but with either a higher or an equal and odd seqno)") if error_code == 33: raise RuntimeError("msg_seqno too high (similarly, there is a message with a higher msg_id but with " "either a lower or an equal and odd seqno)") if error_code == 34: raise RuntimeError("An even msg_seqno expected (irrelevant message), but odd received") if error_code == 35: raise RuntimeError("Odd msg_seqno expected (relevant message), but even received") if error_code == 48: raise RuntimeError("Incorrect server salt (in this case, the bad_server_salt response is received with " "the correct salt, and the message is to be re-sent with it)") if error_code == 64: raise RuntimeError("Invalid container") raise NotImplementedError('This should never happen!') def hangle_msg_detailed_info(self, msg_id, sequence, reader): return False def handle_rpc_result(self, msg_id, sequence, reader, mtproto_request): code = reader.read_int(signed=False) request_id = reader.read_long(signed=False) if request_id == mtproto_request.msg_id: mtproto_request.confirm_received = True inner_code = reader.read_int(signed=False) if inner_code == 0x2144ca19: # RPC Error error_code = reader.read_int() error_msg = reader.tgread_string() if error_msg.startswith('FLOOD_WAIT_'): seconds = int(re.search(r'\d+', error_msg).group(0)) print('Should wait {}s. Sleeping until then.') sleep(seconds) elif error_msg.startswith('PHONE_MIGRATE_'): dc_index = int(re.search(r'\d+', error_msg).group(0)) raise ConnectionError('Your phone number registered to {} dc. Please update settings. ' 'See https://github.com/sochix/TLSharp#i-get-an-error-migrate_x ' 'for details.'.format(dc_index)) else: raise ValueError(error_msg) elif inner_code == 0x3072cfa1: # GZip packed try: packed_data = reader.tgread_bytes() unpacked_data = zlib.decompress(packed_data) with BinaryReader(unpacked_data) as compressed_reader: mtproto_request.on_response(compressed_reader) except: pass else: reader.seek(-4) mtproto_request.on_response(reader) def handle_gzip_packed(self, msg_id, sequence, reader, mtproto_request): code = reader.read_int(signed=False) packed_data = reader.tgread_bytes() unpacked_data = zlib.decompress(packed_data) with BinaryReader(unpacked_data) as compressed_reader: self.process_msg(msg_id, sequence, compressed_reader, mtproto_request) # endregion pass