Telethon/network/mtproto_sender.py
Lonami cdb1674a27 Minor improvement to updates handling
Now the updates thread won't start unless you add,
at least, one updates handler. Also, if the TcpClient
was receiving (i.e., from an update), it will let the
update to be received first instead of crashing
2016-09-11 11:50:38 +02:00

334 lines
13 KiB
Python
Executable File

# This file is based on TLSharp
# https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/Network/MtProtoSender.cs
import gzip
from errors import *
from time import sleep
from threading import Thread, Lock
import utils
from crypto import AES
from utils import BinaryWriter, BinaryReader
from tl.types import MsgsAck
from tl.all_tlobjects import tlobjects
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
self.on_update_handlers = []
# Store a Lock instance to make this class safely multi-threaded
self.lock = Lock()
self.updates_thread = Thread(target=self.updates_thread_method, name='Updates thread')
self.updates_thread_running = False
self.updates_thread_receiving = False
def disconnect(self):
"""Disconnects and **stops all the running threads** if any"""
self.set_listen_for_updates(enabled=False)
self.transport.close()
def add_update_handler(self, handler):
"""Adds an update handler (a method with one argument, the received
TLObject) that is fired when there are updates available"""
first_handler = not self.on_update_handlers
self.on_update_handlers.append(handler)
# If this is the first added handler,
# we must start the thread to receive updates
if first_handler:
self.set_listen_for_updates(enabled=True)
def remove_update_handler(self, handler):
self.on_update_handlers.remove(handler)
# If there are no more update handlers, stop the thread
if not self.on_update_handlers:
self.set_listen_for_updates(False)
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
def send(self, request, resend=False):
"""Sends the specified MTProtoRequest, previously sending any message
which needed confirmation. This also pauses the updates thread"""
# Only cancel the receive *if* it was the
# updates thread who was receiving. We do
# not want to cancel other pending requests!
if self.updates_thread_receiving:
self.transport.cancel_receive()
# Now only us can be using this method if we're not resending
if not resend:
self.lock.acquire()
# If any message needs confirmation send an AckRequest first
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[:]
# Finally 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()
# Don't resume the updates thread yet,
# since every send() is preceded by a receive()
def receive(self, request):
"""Receives the specified MTProtoRequest ("fills in it"
the received data). This also restores the updates thread"""
try:
# Don't stop trying to receive until we get the request we wanted
while not request.confirm_received:
seq, body = self.transport.receive()
message, remote_msg_id, remote_sequence = self.decode_msg(body)
with BinaryReader(message) as reader:
self.process_msg(remote_msg_id, remote_sequence, reader, request)
finally:
# Once we are done trying to get our request,
# restore the updates thread and release the lock
self.lock.release()
# endregion
# region Low level processing
def send_packet(self, packet, request):
"""Sends the given packet bytes with the additional
information of the original request. This does NOT lock the threads!"""
request.msg_id = self.session.get_new_msg_id()
# First calculate plain_text to encrypt it
with BinaryWriter() as plain_writer:
plain_writer.write_long(self.session.salt, signed=False)
plain_writer.write_long(self.session.id, signed=False)
plain_writer.write_long(request.msg_id)
plain_writer.write_int(self.generate_sequence(request.confirmed))
plain_writer.write_int(len(packet))
plain_writer.write(packet)
msg_key = utils.calc_msg_key(plain_writer.get_bytes())
key, iv = utils.calc_key(self.session.auth_key.key, msg_key, True)
cipher_text = AES.encrypt_ige(plain_writer.get_bytes(), key, iv)
# And then finally send the encrypted packet
with BinaryWriter() as cipher_writer:
cipher_writer.write_long(self.session.auth_key.key_id, signed=False)
cipher_writer.write(msg_key)
cipher_writer.write(cipher_text)
self.transport.send(cipher_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 ({})".format(body))
# 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 = utils.calc_key(self.session.auth_key.key, msg_key, False)
plain_text = AES.decrypt_ige(reader.read(len(body) - reader.tell_position()), key, iv)
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=None):
"""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)
# The following codes are "parsed manually"
if code == 0xf35c6d01: # rpc_result, (response of an RPC call, i.e., we sent a request)
return self.handle_rpc_result(msg_id, sequence, reader, request)
if code == 0x73f1f8dc: # msg_container
return self.handle_container(msg_id, sequence, reader, request)
if code == 0x3072cfa1: # gzip_packed
return self.handle_gzip_packed(msg_id, sequence, reader, request)
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 the code is not parsed manually, then it was parsed by the code generator!
# In this case, we will simply treat the incoming TLObject as an Update,
# if we can first find a matching TLObject
if code in tlobjects.keys():
return self.handle_update(msg_id, sequence, reader)
print('Unknown message: {}'.format(hex(code)))
return False
# endregion
# region Message handling
def handle_update(self, msg_id, sequence, reader):
tlobject = reader.tgread_object()
for handler in self.on_update_handlers:
handler(tlobject)
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()
if not self.process_msg(inner_msg_id, sequence, reader, request):
reader.set_position(begin_position + inner_length)
return False
def handle_bad_server_salt(self, msg_id, sequence, reader, 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
if request is None:
raise ValueError('Tried to handle a bad server salt with no request specified')
# Resend
self.send(request, resend=True)
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()
raise BadMessageError(error_code)
def handle_rpc_result(self, msg_id, sequence, reader, request):
if not request:
raise ValueError('RPC results should only happen after a request was sent')
code = reader.read_int(signed=False)
request_id = reader.read_long(signed=False)
inner_code = reader.read_int(signed=False)
if request_id == request.msg_id:
request.confirm_received = True
if inner_code == 0x2144ca19: # RPC Error
error = RPCError(code=reader.read_int(), message=reader.tgread_string())
if error.must_resend:
request.confirm_received = False
if error.message.startswith('FLOOD_WAIT_'):
print('Should wait {}s. Sleeping until then.'.format(error.additional_data))
sleep(error.additional_data)
elif error.message.startswith('PHONE_MIGRATE_'):
raise InvalidDCError(error.additional_data)
else:
raise error
else:
if inner_code == 0x3072cfa1: # GZip packed
unpacked_data = gzip.decompress(reader.tgread_bytes())
with BinaryReader(unpacked_data) as compressed_reader:
request.on_response(compressed_reader)
else:
reader.seek(-4)
request.on_response(reader)
def handle_gzip_packed(self, msg_id, sequence, reader, request):
code = reader.read_int(signed=False)
packed_data = reader.tgread_bytes()
unpacked_data = gzip.decompress(packed_data)
with BinaryReader(unpacked_data) as compressed_reader:
return self.process_msg(msg_id, sequence, compressed_reader, request)
# endregion
def set_listen_for_updates(self, enabled):
if enabled:
if not self.updates_thread_running:
self.updates_thread_running = True
self.updates_thread_receiving = False
self.updates_thread.start()
else:
self.updates_thread_running = False
if self.updates_thread_receiving:
self.transport.cancel_receive()
def updates_thread_method(self):
"""This method will run until specified and listen for incoming updates"""
while self.updates_thread_running:
with self.lock:
try:
self.updates_thread_receiving = True
seq, body = self.transport.receive()
message, remote_msg_id, remote_sequence = self.decode_msg(body)
with BinaryReader(message) as reader:
self.process_msg(remote_msg_id, remote_sequence, reader)
except ReadCancelledError:
pass
self.updates_thread_receiving = False
# If we are here, it is because the read was cancelled
# Sleep a bit just to give enough time for the other thread
# to acquire the lock. No need to sleep if we're not running anymore
if self.updates_thread_running:
sleep(0.1)