add torrent udp tracker client, server and tests

This commit is contained in:
Victor Shyba 2022-03-05 02:12:11 -03:00
parent d0e715feb9
commit 4a0bf8a702
3 changed files with 168 additions and 0 deletions

141
lbry/torrent/tracker.py Normal file
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import random
import struct
import asyncio
import logging
from collections import namedtuple
from functools import reduce
log = logging.getLogger(__name__)
ConnectRequest = namedtuple("ConnectRequest", ["connection_id", "action", "transaction_id"])
ConnectResponse = namedtuple("ConnectResponse", ["action", "transaction_id", "connection_id"])
AnnounceRequest = namedtuple("AnnounceRequest",
["connection_id", "action", "transaction_id", "info_hash", "peer_id", "downloaded", "left",
"uploaded", "event", "ip_addr", "key", "num_want", "port"])
AnnounceResponse = namedtuple("AnnounceResponse",
["action", "transaction_id", "interval", "leechers", "seeders", "peers"])
CompactIPv4Peer = namedtuple("CompactPeer", ["address", "port"])
ScrapeRequest = namedtuple("ScrapeRequest", ["connection_id", "action", "transaction_id", "infohashes"])
ScrapeResponse = namedtuple("ScrapeResponse", ["action", "transaction_id", "items"])
ScrapeResponseItem = namedtuple("ScrapeResponseItem", ["seeders", "completed", "leechers"])
ErrorResponse = namedtuple("ErrorResponse", ["action", "transaction_id", "message"])
STRUCTS = {
ConnectRequest: struct.Struct(">QII"),
ConnectResponse: struct.Struct(">IIQ"),
AnnounceRequest: struct.Struct(">QII20s20sQQQIIIiH"),
AnnounceResponse: struct.Struct(">IIIII"),
CompactIPv4Peer: struct.Struct(">IH"),
ScrapeRequest: struct.Struct(">QII"),
ScrapeResponse: struct.Struct(">II"),
ScrapeResponseItem: struct.Struct(">III"),
ErrorResponse: struct.Struct(">II")
}
def decode(cls, data, offset=0):
decoder = STRUCTS[cls]
if cls == AnnounceResponse:
return AnnounceResponse(*decoder.unpack_from(data, offset),
peers=[decode(CompactIPv4Peer, data, index) for index in range(20, len(data), 6)])
elif cls == ScrapeResponse:
return ScrapeResponse(*decoder.unpack_from(data, offset),
items=[decode(ScrapeResponseItem, data, index) for index in range(8, len(data), 12)])
elif cls == ErrorResponse:
return ErrorResponse(*decoder.unpack_from(data, offset), data[decoder.size:])
return cls(*decoder.unpack_from(data, offset))
def encode(obj):
if isinstance(obj, ScrapeRequest):
return STRUCTS[ScrapeRequest].pack(*obj[:-1]) + b''.join(obj.infohashes)
elif isinstance(obj, ErrorResponse):
return STRUCTS[ErrorResponse].pack(*obj[:-1]) + obj.message
elif isinstance(obj, AnnounceResponse):
return STRUCTS[AnnounceResponse].pack(*obj[:-1]) + b''.join([encode(peer) for peer in obj.peers])
return STRUCTS[type(obj)].pack(*obj)
class UDPTrackerClientProtocol(asyncio.DatagramProtocol):
def __init__(self):
self.transport = None
self.data_queue = {}
def connection_made(self, transport: asyncio.DatagramTransport) -> None:
self.transport = transport
async def request(self, obj, tracker_ip, tracker_port):
self.data_queue[obj.transaction_id] = asyncio.get_running_loop().create_future()
self.transport.sendto(encode(obj), (tracker_ip, tracker_port))
try:
return await asyncio.wait_for(self.data_queue[obj.transaction_id], 3.0)
finally:
self.data_queue.pop(obj.transaction_id, None)
async def connect(self, tracker_ip, tracker_port):
transaction_id = random.getrandbits(32)
return decode(ConnectResponse,
await self.request(ConnectRequest(0x41727101980, 0, transaction_id), tracker_ip, tracker_port))
async def announce(self, info_hash, peer_id, port, tracker_ip, tracker_port, connection_id=None):
if not connection_id:
reply = await self.connect(tracker_ip, tracker_port)
connection_id = reply.connection_id
# this should make the key deterministic but unique per info hash + peer id
key = int.from_bytes(info_hash[:4], "big") ^ int.from_bytes(peer_id[:4], "big") ^ port
transaction_id = random.getrandbits(32)
req = AnnounceRequest(connection_id, 1, transaction_id, info_hash, peer_id, 0, 0, 0, 1, 0, key, -1, port)
reply = await self.request(req, tracker_ip, tracker_port)
return decode(AnnounceResponse, reply), connection_id
async def scrape(self, infohashes, tracker_ip, tracker_port, connection_id=None):
if not connection_id:
reply = await self.connect(tracker_ip, tracker_port)
connection_id = reply.connection_id
transaction_id = random.getrandbits(32)
reply = await self.request(
ScrapeRequest(connection_id, 2, transaction_id, infohashes), tracker_ip, tracker_port)
return decode(ScrapeResponse, reply), connection_id
def datagram_received(self, data: bytes, addr: (str, int)) -> None:
if len(data) < 8:
return
transaction_id = int.from_bytes(data[4:8], byteorder="big", signed=False)
if transaction_id in self.data_queue:
if not self.data_queue[transaction_id].done():
if data[3] == 3:
return self.data_queue[transaction_id].set_exception(Exception(decode(ErrorResponse, data).message))
return self.data_queue[transaction_id].set_result(data)
print("error", data.hex())
def connection_lost(self, exc: Exception = None) -> None:
self.transport = None
class UDPTrackerServerProtocol(asyncio.DatagramProtocol):
def __init__(self):
self.transport = None
self.known_conns = set()
self.peers = {}
def connection_made(self, transport: asyncio.DatagramTransport) -> None:
self.transport = transport
def datagram_received(self, data: bytes, address: (str, int)) -> None:
if len(data) < 16:
return
action = int.from_bytes(data[8:12], "big", signed=False)
if action == 0:
req = decode(ConnectRequest, data)
connection_id = random.getrandbits(32)
self.known_conns.add(connection_id)
return self.transport.sendto(encode(ConnectResponse(0, req.transaction_id, connection_id)), address)
elif action == 1:
req = decode(AnnounceRequest, data)
if req.connection_id not in self.known_conns:
resp = encode(ErrorResponse(3, req.transaction_id, b'Connection ID missmatch.\x00'))
else:
self.peers.setdefault(req.info_hash, [])
compact_ip = reduce(lambda buff, x: buff + bytearray([int(x)]), address[0].split('.'), bytearray())
self.peers[req.info_hash].append(compact_ip + req.port.to_bytes(2, "big", signed=False))
peers = [decode(CompactIPv4Peer, peer) for peer in self.peers[req.info_hash]]
resp = encode(AnnounceResponse(1, req.transaction_id, 1700, 0, len(peers), peers))
return self.transport.sendto(resp, address)

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import random
from lbry.testcase import AsyncioTestCase
from lbry.torrent.tracker import UDPTrackerClientProtocol, UDPTrackerServerProtocol, CompactIPv4Peer
class UDPTrackerClientTestCase(AsyncioTestCase):
async def asyncSetUp(self):
transport, _ = await self.loop.create_datagram_endpoint(UDPTrackerServerProtocol, local_addr=("127.0.0.1", 59900))
self.addCleanup(transport.close)
self.client = UDPTrackerClientProtocol()
transport, _ = await self.loop.create_datagram_endpoint(lambda: self.client, local_addr=("127.0.0.1", 0))
self.addCleanup(transport.close)
async def test_announce(self):
info_hash = random.getrandbits(160).to_bytes(20, "big", signed=False)
peer_id = random.getrandbits(160).to_bytes(20, "big", signed=False)
announcement, _ = await self.client.announce(info_hash, peer_id, 4444, "127.0.0.1", 59900)
self.assertEqual(announcement.seeders, 1)
self.assertEqual(announcement.peers,
[CompactIPv4Peer(int.from_bytes(bytes([127, 0, 0, 1]), "big", signed=False), 4444)])
async def test_error(self):
info_hash = random.getrandbits(160).to_bytes(20, "big", signed=False)
peer_id = random.getrandbits(160).to_bytes(20, "big", signed=False)
with self.assertRaises(Exception) as err:
announcement, _ = await self.client.announce(info_hash, peer_id, 4444, "127.0.0.1", 59900, connection_id=10)
self.assertEqual(err.exception.args[0], b'Connection ID missmatch.\x00')