Telethon/network/mtproto_sender.py
Lonami 5b4be5b85e Fixed bugs when handling updates
GZipPacked updates are now handled correctly.
Also, fixed another bug which did not allow
resending a request when BadServerSalt occured.
2016-09-10 20:06:37 +02:00

320 lines
12 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"""
self.on_update_handlers.append(handler)
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)