Call discarded after confirming

[huco95]

Checklist

• The error is in the library's code, and not in my own.
• I have searched for this issue before posting it and there isn't a duplicate.
• I ran pip install -U https://github.com/LonamiWebs/Telethon/archive/v1.zip and triggered the bug in the latest version.

I have updated the code from Telethon-calls to the lastest version, I managed to request and confirm the call, but after confirming the call it is disconnected. Any idea why this is happening? Thanks!

Code that causes the issue

import logging
logging.basicConfig(format='[%(levelname) 5s/%(asctime)s] %(name)s: %(message)s',
                    level=logging.WARNING)

import asyncio
import hashlib
import os
import random

from telethon import TelegramClient, events
from telethon.tl.functions.messages import GetDhConfigRequest
from telethon.tl.functions.phone import  RequestCallRequest, ConfirmCallRequest
from telethon.tl.types import PhoneCallEmpty, PhoneCallWaiting, \
    PhoneCallRequested, PhoneCallDiscarded, PhoneCall, PhoneCallAccepted, \
    UpdatePhoneCall, PhoneCallProtocol, InputPhoneCall, Updates, UpdateShort
from pyrogram.raw import types

api_id = 0
api_hash = ''
phone_number = '' 

call_state = None
client = TelegramClient('arm_call_test2', api_id, api_hash)

@client.on(events.Raw)
async def handler(update):
    await process_update(update)

class DH:
    def __init__(self, dhc: types.messages.DhConfig):
        self.p = bytes_to_integer(dhc.p)
        self.g = dhc.g
        self.resp = dhc

class DynamicDict:
    def __setattr__(self, key, value):
        self.__dict__[key] = value

def get_rand_bytes(dh_config, length=256):
    return bytes(x ^ y for x, y in zip(
        os.urandom(length), dh_config.resp.random
    ))

def bytes_to_integer(bytes):
    return int.from_bytes(bytes, 'big')

def integer_to_bytes(integer):
    return int.to_bytes(
        integer,
        length=(integer.bit_length() + 8 - 1) // 8,  # 8 bits per byte,
        byteorder='big',
        signed=False
    )

def calc_fingerprint(key):
    return int.from_bytes(
        bytes(hashlib.sha1(key).digest()[-8:]), 'little', signed=True
    )

async def process_update(update):
    if isinstance(update, UpdatePhoneCall):
        print('[CALL] Phone call update:', update.phone_call)
        await process_phone_call(update.phone_call)
    elif isinstance(update, Updates):
        for u in update.updates:
            await process_update(u)
    elif isinstance(update, UpdateShort):
        await process_update(update.update)
    else:
        pass
        #print('Ignoring', type(update).__name__)

async def process_phone_call(call):
    global call_state
    if isinstance(call, PhoneCallEmpty):
        pass
    elif isinstance(call, PhoneCallWaiting):
        print('[CALL] Waiting for', call.participant_id, 'to answer...')
    elif isinstance(call, PhoneCallRequested):
        print('[CALL] Incoming call from', call.participant_id)
        # accept_call(call)
    elif isinstance(call, PhoneCallDiscarded):
            state = call_state
            print('[CALL]', state.user_id, 'discarded your call because of', type(call.reason).__name__)        # del calls[call.id]
            client.disconnect()
    elif isinstance(call, PhoneCall):
        print('[CALL] Call', call.id, 'is now', type(call).__name__)
        process_full_call(call)
    elif isinstance(call, PhoneCallAccepted):
        print('[CALL] Call accepted by', call.participant_id, '! Doing stage 2')
        await call_stage_two(call)
    else:
        print('[call] ignoring', type(call), call)

async def call_stage_two(call):
    global call_state
    state = call_state
    state.prt_proto = call.protocol  # TODO Hm, why not my_proto?
    print('prt', state.prt_proto)
    print('myp', state.my_proto)

    state.g_b = int.from_bytes(call.g_b, 'little')
    state.key = pow(state.g_b, state.a, state.p)
    state.key_fingerprint = calc_fingerprint(integer_to_bytes(state.key))

    call_state = state

    phone_call = await client(ConfirmCallRequest(
        peer=InputPhoneCall(call.id, call.access_hash),
        g_a=integer_to_bytes(state.g_a),
        key_fingerprint=state.key_fingerprint,
        protocol=state.prt_proto
    ))

    print('[CALL] Call confirmed:', phone_call)
    return await process_phone_call(phone_call.phone_call)

def process_full_call(call):
    global call_state
    state = call_state
    print('[CALL] Processing full call', call)
    print('[CALL] Full state currently', state.__dict__)
    if state.incoming:
        print('[CALL] Got more info about call from', call.admin_id, 'we have accepted.')
        state.g_a = int.from_bytes(call.g_a_or_b, 'big')

        state.pt_g_a_hash = hashlib.sha256(call.g_a_or_b).digest()
        if state.pt_g_a_hash != state.g_a_hash:
            print('[CALL] HASH(G_A) != G_A_HASH!', state.pt_g_a_hash, state.g_a_hash)
        else:
            print('[CALL] g_a hash is correct!')

        state.key = pow(state.g_a, state.b, state.p)
        state.key_fingerprint = calc_fingerprint(integer_to_bytes(state.key))
        print('[CALL] Calculated fingerprint', repr(state.key_fingerprint), 'with key', repr(state.key))

        state.pt_key_fingerprint = call.key_fingerprint
        if state.pt_key_fingerprint != state.key_fingerprint:
            print('[CALL] Fingerprint mismatch! Got', state.pt_key_fingerprint, 'expected', state.key_fingerprint)

    state.connections = call.connections
    # state.alternative_connections = call.alternative_connections

    call_state = state

    print('[CALL] Call #', call.id, 'ready!')
    
async def main():    
    await client.start()

    dhc = DH(await client(GetDhConfigRequest(0, 256)))
    state = DynamicDict()
    state.incoming = False

    state.user_id = "@user"
    state.random_id = random.randint(0, 0x7fffffff - 1)

    state.g = dhc.g
    state.p = dhc.p

    state.a = 0
    while not (1 < state.a < state.p - 1):
        # "A chooses a random value of a, 1 < a < p-1"
        state.a = int.from_bytes(get_rand_bytes(dh_config=dhc), 'little')

    state.a = random.randint(2, state.p - 1)
    state.g_a = pow(state.g, state.a, state.p)
    state.g_a_hash = hashlib.sha256(integer_to_bytes(state.g_a)).digest()
    state.my_proto = PhoneCallProtocol(
            min_layer=92,
            max_layer=92,
            udp_p2p=True,
            udp_reflector=True,
            library_versions=['3.0.0'],
        )

    phone_call = await client(RequestCallRequest(
        user_id=state.user_id,
        random_id=state.random_id,
        g_a_hash=state.g_a_hash,
        protocol=state.my_proto
    ))

    print(phone_call)
    print(phone_call.phone_call.id)
    state.peer = InputPhoneCall(phone_call.phone_call.id, phone_call.phone_call.access_hash)
    global call_state
    call_state = state
    await process_phone_call(phone_call.phone_call)

    await client.run_until_disconnected()

asyncio.run(main())

Logs

[CALL] Waiting for xxx to answer...
[CALL] Phone call update:
[CALL] Waiting for xxx to answer...
[CALL] Phone call update
[CALL] Call accepted by xxx ! Doing stage 2
[CALL] Call confirmed
[CALL] Call xxx is now PhoneCall
[CALL] Processing full call 
[CALL] @user discarded your call because of PhoneCallDiscardReasonDisconnect

[Lonami]

I do not have experience with Telegram calls so unfortunately I can't really help. There's nothing in Telethon in particular that would be declining the calls automatically, so I'm not sure what could be wrong. Maybe it's auto-declined if some parameter is wrong or something, no idea.

[Lonami]

Well I guess I can keep this open and try to take a closer look eventually.

[Lonami]

I took a look and noticed the following:

• process_update tries to handle both Updates and UpdatesShort but the library shouldn't be dispatching these via events.Raw (not that this should affect the program's outcome in this case).
• Phone call update: seems cut, not sure if it's intentional. I guess it doesn't matter since process_phone_call has more prints which help tell which update it was.
• I'm not sure if this is the way calls work but seeing two PhoneCallWaiting seems strange.

Other than that, yeah, I have no idea. Does this behavior occur if Telethon calls Telegram Desktop? Telegram Android? Telegram X? Pyrogram? Does this happen if those call Telethon instead?

[Lonami]

I tried the above code to call another account of mine on Telegram X and this is the output:

PhoneCall(phone_call=PhoneCallWaiting(id=100001, access_hash=100002, date=datetime.datetime(2022, 11, 23, 19, 24, 13, tzinfo=datetime.timezone.utc), admin_id=1001, participant_id=1002, protocol=PhoneCallProtocol(min_layer=92, max_layer=92, library_versions=['2.4.4'], udp_p2p=True, udp_reflector=True), video=False, receive_date=None), users=[User(id=1001, is_self=True, contact=True, mutual_contact=False, deleted=False, bot=False, bot_chat_history=False, bot_nochats=False, verified=False, restricted=False, min=False, bot_inline_geo=False, support=False, scam=False, apply_min_photo=True, fake=False, bot_attach_menu=False, premium=True, attach_menu_enabled=False, access_hash=100000003, first_name='lonami', last_name=None, username='lonami', phone='34600000001', photo=UserProfilePhoto(photo_id=10000004, dc_id=4, has_video=True, stripped_thumb=b'\x01\x08\x08\xd1\xcb\x8b\x8c\x10v\xfa\xd1E\x14\x86\x7f'), status=UserStatusOnline(expires=datetime.datetime(2022, 11, 23, 19, 28, 48, tzinfo=datetime.timezone.utc)), bot_info_version=None, restriction_reason=[], bot_inline_placeholder=None, lang_code=None, emoji_status=EmojiStatus(document_id=1000005)), User(id=1002, is_self=False, contact=True, mutual_contact=True, deleted=False, bot=False, bot_chat_history=False, bot_nochats=False, verified=False, restricted=False, min=False, bot_inline_geo=False, support=False, scam=False, apply_min_photo=False, fake=False, bot_attach_menu=False, premium=False, attach_menu_enabled=False, access_hash=1000006, first_name='alt', last_name=None, username='-', phone='34600000002', photo=None, status=UserStatusRecently(), bot_info_version=None, restriction_reason=[], bot_inline_placeholder=None, lang_code=None, emoji_status=None)])
100001
[CALL] Waiting for 1002 to answer...
[CALL] Phone call update: PhoneCallWaiting(id=100001, access_hash=100002, date=datetime.datetime(2022, 11, 23, 19, 24, 13, tzinfo=datetime.timezone.utc), admin_id=1001, participant_id=1002, protocol=PhoneCallProtocol(min_layer=92, max_layer=92, library_versions=['2.4.4'], udp_p2p=True, udp_reflector=True), video=False, receive_date=datetime.datetime(2022, 11, 23, 19, 24, 13, tzinfo=datetime.timezone.utc))
[CALL] Waiting for 1002 to answer...
[CALL] Phone call update: PhoneCallDiscarded(id=100001, need_rating=False, need_debug=False, video=False, reason=PhoneCallDiscardReasonMissed(), duration=None)
[CALL] @- discarded your call because of PhoneCallDiscardReasonMissed

If I do it but discard:

...
[CALL] Phone call update: PhoneCallDiscarded(id=100009, need_rating=False, need_debug=False, video=False, reason=PhoneCallDiscardReasonBusy(), duration=None)
[CALL] @- discarded your call because of PhoneCallDiscardReasonBusy

If I do it accepting with Telegram I do reach PhoneCallDiscardReasonDisconnect.

If I do it discarding with Telegram I get PhoneCallDiscardReasonHangup.

So yeah it's really strange.

[Lonami]

Actually PhoneCallProtocol is setting udp_p2p. Shouldn't this mean there should be a peer-to-peer connection to the other client? I can't see any. On the other hand setting that to False doesn't seem to change much....

[huco95]

Thanks a lot for your time @Lonami!!
I made some little chanes based on your messages.
I have also checked the telegram documentation about calls, https://core.telegram.org/api/end-to-end/voice-calls, becasuse I think the problem can be related with the g_a, g_a_hash and key_fingerprint generation but I can't figure it out.

import logging
logging.basicConfig(format='[%(levelname) 5s/%(asctime)s] %(name)s: %(message)s', level=logging.WARNING)

import asyncio
import hashlib
import os
import random

from telethon import TelegramClient, events
from telethon.tl.functions.messages import GetDhConfigRequest
from telethon.tl.functions.phone import  RequestCallRequest, ConfirmCallRequest
from telethon.tl.types import PhoneCallEmpty, PhoneCallWaiting, \
    PhoneCallRequested, PhoneCallDiscarded, PhoneCall, PhoneCallAccepted, \
    UpdatePhoneCall, PhoneCallProtocol, InputPhoneCall, Updates, UpdateShort
from pyrogram.raw import types

api_id = 0
api_hash = ''
phone_number = '' 

call_state = None
client = TelegramClient('call_test', api_id, api_hash)

@client.on(events.Raw)
async def handler(update):
    await process_update(update)

class DH:
    def __init__(self, dhc: types.messages.DhConfig):
        self.p = bytes_to_integer(dhc.p)
        self.g = dhc.g
        self.resp = dhc

class DynamicDict:
    def __setattr__(self, key, value):
        self.__dict__[key] = value

def get_rand_bytes(dh_config, length=256):
    return bytes(x ^ y for x, y in zip(
        os.urandom(length), dh_config.resp.random
    ))

def bytes_to_integer(bytes):
    return int.from_bytes(bytes, 'big')

def integer_to_bytes(integer):
    return int.to_bytes(
        integer,
        length=(integer.bit_length() + 8 - 1) // 8,  # 8 bits per byte,
        byteorder='big',
        signed=False
    )

def calc_fingerprint(key):
    return int.from_bytes(
        bytes(hashlib.sha1(key).digest()[-8:]), 'little', signed=True
    )

async def process_update(update):
    if isinstance(update, UpdatePhoneCall):
        print('[CALL] Phone call update:', update.phone_call)
        await process_phone_call(update.phone_call)
    else:
        print('Ignoring', type(update).__name__)

async def process_phone_call(call):
    global call_state
    if isinstance(call, PhoneCallEmpty):
        print('[CALL] Phone call empty')
    elif isinstance(call, PhoneCallWaiting):
        print('[CALL] Waiting for', call.participant_id, 'to answer...')
    elif isinstance(call, PhoneCallRequested):
        print('[CALL] Incoming call from', call.participant_id)
        # accept_call(call)
    elif isinstance(call, PhoneCallDiscarded):
            state = call_state
            print('[CALL]', state.user_id, 'discarded your call because of', type(call.reason).__name__)        # del calls[call.id]
            client.disconnect()
    elif isinstance(call, PhoneCall):
        print('[CALL] Call', call.id, 'is now', type(call).__name__)
        process_full_call(call)
    elif isinstance(call, PhoneCallAccepted):
        print('[CALL] Call accepted by', call.participant_id, '! Doing stage 2')
        await call_stage_two(call)
    else:
        print('[call] ignoring', type(call), call)

async def call_stage_two(call):
    global call_state
    state = call_state
    state.prt_proto = call.protocol  # TODO Hm, why not my_proto?
    print('prt', state.prt_proto)
    print('myp', state.my_proto)

    state.g_b = int.from_bytes(call.g_b, 'big')
    state.key = pow(base=state.g_b, exp=state.a, mod=state.p)
    state.key_fingerprint = calc_fingerprint(integer_to_bytes(state.key))

    call_state = state

    phone_call = await client(ConfirmCallRequest(
        peer=InputPhoneCall(call.id, call.access_hash),
        g_a=integer_to_bytes(state.g_a),
        key_fingerprint=state.key_fingerprint,
        protocol=state.prt_proto
    ))

    print('[CALL] Call confirmed:', phone_call)

def process_full_call(call):
    global call_state
    state = call_state
    print('[CALL] Processing full call', call)
    print('[CALL] Full state currently', state.__dict__)

    state.connections = call.connections

    # Validate fingerprint
    state.key = pow(state.g_b, state.a, state.p)
    state.key_fingerprint = calc_fingerprint(integer_to_bytes(state.key))
    state.pt_key_fingerprint = call.key_fingerprint
    if state.pt_key_fingerprint != state.key_fingerprint:
        print('[CALL] Fingerprint mismatch! Got', state.pt_key_fingerprint, 'expected', state.key_fingerprint)
    else:
        print('[CALL] Fingerprint is correct!')

    call_state = state

    print('[CALL] Call #', call.id, 'ready!')
    
async def main():    
    await client.start()

    dhc = DH(await client(GetDhConfigRequest(0, 256)))
    state = DynamicDict()
    state.incoming = False

    state.user_id = "@user"
    state.random_id = random.randint(0, 0x7fffffff - 1)

    state.g = dhc.g
    state.p = dhc.p

    state.a = 0
    while not (1 < state.a < state.p - 1):
        # "A chooses a random value of a, 1 < a < p-1"
        state.a = int.from_bytes(get_rand_bytes(dh_config=dhc), 'big')

    state.a = random.randint(2, state.p - 1)
    state.g_a = pow(base=state.g, exp=state.a, mod=state.p)
    state.g_a_hash = hashlib.sha256(integer_to_bytes(state.g_a)).digest()
    state.my_proto = PhoneCallProtocol(
            min_layer=92,
            max_layer=92,
            udp_p2p=True,
            udp_reflector=True,
            library_versions=['3.0.0'],
        )

    phone_call = await client(RequestCallRequest(
        user_id=state.user_id,
        random_id=state.random_id,
        g_a_hash=state.g_a_hash,
        protocol=state.my_proto
    ))

    print("Phone call (", phone_call.phone_call.id, ") request sent, waiting for updates...")
    state.peer = InputPhoneCall(phone_call.phone_call.id, phone_call.phone_call.access_hash)
    global call_state
    call_state = state

    await client.run_until_disconnected()

asyncio.run(main())

[Lonami]

I'm going through the list of issues to fix some of them and found this again. I don't think this issue is actionable from my side. Were you able to make any progress? Would you mind if I closed this issue here (if it's not something I can "fix" in Telethon, it doesn't make much sense to keep an issue open for it)?

If you have an issue for this elsewhere, I can watch that issue, so I can participate there instead.

[Lonami]

Closing due to the lack of response, but we can reopen if you think there's a need.

[nardonycc]

to switch off

How would I disconnect the call?