import asyncio
from itertools import chain
from collections import defaultdict, OrderedDict
from collections.abc import AsyncIterator
import typing
import logging
from typing import TYPE_CHECKING
from lbry.dht import constants
from lbry.dht.error import RemoteException, TransportNotConnected
from lbry.dht.protocol.distance import Distance
from lbry.dht.peer import make_kademlia_peer, decode_tcp_peer_from_compact_address
from lbry.dht.serialization.datagram import PAGE_KEY
if TYPE_CHECKING:
from lbry.dht.protocol.protocol import KademliaProtocol
from lbry.dht.peer import PeerManager, KademliaPeer
log = logging.getLogger(__name__)
class FindResponse:
@property
def found(self) -> bool:
raise NotImplementedError()
def get_close_triples(self) -> typing.List[typing.Tuple[bytes, str, int]]:
raise NotImplementedError()
def get_close_kademlia_peers(self, peer_info) -> typing.Generator[typing.Iterator['KademliaPeer'], None, None]:
for contact_triple in self.get_close_triples():
node_id, address, udp_port = contact_triple
try:
yield make_kademlia_peer(node_id, address, udp_port)
except ValueError:
log.warning("misbehaving peer %s:%i returned peer with reserved ip %s:%i", peer_info.address,
peer_info.udp_port, address, udp_port)
class FindNodeResponse(FindResponse):
def __init__(self, key: bytes, close_triples: typing.List[typing.Tuple[bytes, str, int]]):
self.key = key
self.close_triples = close_triples
@property
def found(self) -> bool:
return self.key in [triple[0] for triple in self.close_triples]
def get_close_triples(self) -> typing.List[typing.Tuple[bytes, str, int]]:
return self.close_triples
class FindValueResponse(FindResponse):
def __init__(self, key: bytes, result_dict: typing.Dict):
self.key = key
self.token = result_dict[b'token']
self.close_triples: typing.List[typing.Tuple[bytes, bytes, int]] = result_dict.get(b'contacts', [])
self.found_compact_addresses = result_dict.get(key, [])
self.pages = int(result_dict.get(PAGE_KEY, 0))
@property
def found(self) -> bool:
return len(self.found_compact_addresses) > 0
def get_close_triples(self) -> typing.List[typing.Tuple[bytes, str, int]]:
return [(node_id, address.decode(), port) for node_id, address, port in self.close_triples]
class IterativeFinder(AsyncIterator):
def __init__(self, loop: asyncio.AbstractEventLoop,
protocol: 'KademliaProtocol', key: bytes,
max_results: typing.Optional[int] = constants.K,
shortlist: typing.Optional[typing.List['KademliaPeer']] = None):
if len(key) != constants.HASH_LENGTH:
raise ValueError("invalid key length: %i" % len(key))
self.loop = loop
self.peer_manager = protocol.peer_manager
self.protocol = protocol
self.key = key
self.max_results = max(constants.K, max_results)
self.active: typing.Dict['KademliaPeer', int] = OrderedDict() # peer: distance, sorted
self.contacted: typing.Set['KademliaPeer'] = set()
self.distance = Distance(key)
self.iteration_queue = asyncio.Queue(loop=self.loop)
self.running_probes: typing.Dict['KademliaPeer', asyncio.Task] = {}
self.iteration_count = 0
self.running = False
self.tasks: typing.List[asyncio.Task] = []
for peer in shortlist:
if peer.node_id:
self._add_active(peer, force=True)
else:
# seed nodes
self._schedule_probe(peer)
async def send_probe(self, peer: 'KademliaPeer') -> FindResponse:
"""
Send the rpc request to the peer and return an object with the FindResponse interface
"""
raise NotImplementedError()
def search_exhausted(self):
"""
This method ends the iterator due no more peers to contact.
Override to provide last time results.
"""
self.iteration_queue.put_nowait(None)
def check_result_ready(self, response: FindResponse):
"""
Called after adding peers from an rpc result to the shortlist.
This method is responsible for putting a result for the generator into the Queue
"""
raise NotImplementedError()
def get_initial_result(self) -> typing.List['KademliaPeer']: #pylint: disable=no-self-use
"""
Get an initial or cached result to be put into the Queue. Used for findValue requests where the blob
has peers in the local data store of blobs announced to us
"""
return []
def _add_active(self, peer, force=False):
if not force and self.peer_manager.peer_is_good(peer) is False:
return
if peer in self.contacted:
return
if peer not in self.active and peer.node_id and peer.node_id != self.protocol.node_id:
self.active[peer] = self.distance(peer.node_id)
self.active = OrderedDict(sorted(self.active.items(), key=lambda item: item[1]))
async def _handle_probe_result(self, peer: 'KademliaPeer', response: FindResponse):
self._add_active(peer)
for new_peer in response.get_close_kademlia_peers(peer):
self._add_active(new_peer)
self.check_result_ready(response)
self._log_state(reason="check result")
def _reset_closest(self, peer):
if peer in self.active:
del self.active[peer]
async def _send_probe(self, peer: 'KademliaPeer'):
try:
response = await self.send_probe(peer)
except asyncio.TimeoutError:
self._reset_closest(peer)
return
except asyncio.CancelledError:
log.debug("%s[%x] cancelled probe",
type(self).__name__, id(self))
raise
except ValueError as err:
log.warning(str(err))
self._reset_closest(peer)
return
except TransportNotConnected:
await self._aclose(reason="not connected")
return
except RemoteException:
self._reset_closest(peer)
return
return await self._handle_probe_result(peer, response)
def _search_round(self):
"""
Send up to constants.alpha (5) probes to closest active peers
"""
added = 0
for index, peer in enumerate(self.active.keys()):
if index == 0:
log.debug("%s[%x] closest to probe: %s",
type(self).__name__, id(self),
peer.node_id.hex()[:8])
if peer in self.contacted:
continue
if len(self.running_probes) >= constants.ALPHA:
break
if index > (constants.K + len(self.running_probes)):
break
origin_address = (peer.address, peer.udp_port)
if peer.node_id == self.protocol.node_id:
continue
if origin_address == (self.protocol.external_ip, self.protocol.udp_port):
continue
self._schedule_probe(peer)
added += 1
log.debug("%s[%x] running %d probes for key %s",
type(self).__name__, id(self),
len(self.running_probes), self.key.hex()[:8])
if not added and not self.running_probes:
log.debug("%s[%x] search for %s exhausted",
type(self).__name__, id(self),
self.key.hex()[:8])
self.search_exhausted()
def _schedule_probe(self, peer: 'KademliaPeer'):
self.contacted.add(peer)
t = self.loop.create_task(self._send_probe(peer))
def callback(_):
self.running_probes.pop(peer, None)
if self.running:
self._search_round()
t.add_done_callback(callback)
self.running_probes[peer] = t
def _log_state(self, reason="?"):
log.debug("%s[%x] [%s] %s: %i active nodes %i contacted %i produced %i queued",
type(self).__name__, id(self), self.key.hex()[:8],
reason, len(self.active), len(self.contacted),
self.iteration_count, self.iteration_queue.qsize())
def __aiter__(self):
if self.running:
raise Exception("already running")
self.running = True
self.loop.call_soon(self._search_round)
return self
async def __anext__(self) -> typing.List['KademliaPeer']:
try:
if self.iteration_count == 0:
result = self.get_initial_result() or await self.iteration_queue.get()
else:
result = await self.iteration_queue.get()
if not result:
raise StopAsyncIteration
self.iteration_count += 1
return result
except asyncio.CancelledError:
await self._aclose(reason="cancelled")
raise
except StopAsyncIteration:
await self._aclose(reason="no more results")
raise
async def _aclose(self, reason="?"):
log.debug("%s[%x] [%s] shutdown because %s: %i active nodes %i contacted %i produced %i queued",
type(self).__name__, id(self), self.key.hex()[:8],
reason, len(self.active), len(self.contacted),
self.iteration_count, self.iteration_queue.qsize())
self.running = False
self.iteration_queue.put_nowait(None)
for task in chain(self.tasks, self.running_probes.values()):
task.cancel()
self.tasks.clear()
self.running_probes.clear()
async def aclose(self):
if self.running:
await self._aclose(reason="aclose")
log.debug("%s[%x] [%s] async close completed",
type(self).__name__, id(self), self.key.hex()[:8])
class IterativeNodeFinder(IterativeFinder):
def __init__(self, loop: asyncio.AbstractEventLoop,
protocol: 'KademliaProtocol', key: bytes,
max_results: typing.Optional[int] = constants.K,
shortlist: typing.Optional[typing.List['KademliaPeer']] = None):
super().__init__(loop, protocol, key, max_results, shortlist)
self.yielded_peers: typing.Set['KademliaPeer'] = set()
async def send_probe(self, peer: 'KademliaPeer') -> FindNodeResponse:
log.debug("probe %s:%d (%s) for NODE %s",
peer.address, peer.udp_port, peer.node_id.hex()[:8] if peer.node_id else '', self.key.hex()[:8])
response = await self.protocol.get_rpc_peer(peer).find_node(self.key)
return FindNodeResponse(self.key, response)
def search_exhausted(self):
self.put_result(self.active.keys(), finish=True)
def put_result(self, from_iter: typing.Iterable['KademliaPeer'], finish=False):
not_yet_yielded = [
peer for peer in from_iter
if peer not in self.yielded_peers
and peer.node_id != self.protocol.node_id
and self.peer_manager.peer_is_good(peer) is True # return only peers who answered
]
not_yet_yielded.sort(key=lambda peer: self.distance(peer.node_id))
to_yield = not_yet_yielded[:max(constants.K, self.max_results)]
if to_yield:
self.yielded_peers.update(to_yield)
self.iteration_queue.put_nowait(to_yield)
if finish:
self.iteration_queue.put_nowait(None)
def check_result_ready(self, response: FindNodeResponse):
found = response.found and self.key != self.protocol.node_id
if found:
log.debug("found")
return self.put_result(self.active.keys(), finish=True)
class IterativeValueFinder(IterativeFinder):
def __init__(self, loop: asyncio.AbstractEventLoop,
protocol: 'KademliaProtocol', key: bytes,
max_results: typing.Optional[int] = constants.K,
shortlist: typing.Optional[typing.List['KademliaPeer']] = None):
super().__init__(loop, protocol, key, max_results, shortlist)
self.blob_peers: typing.Set['KademliaPeer'] = set()
# this tracks the index of the most recent page we requested from each peer
self.peer_pages: typing.DefaultDict['KademliaPeer', int] = defaultdict(int)
# this tracks the set of blob peers returned by each peer
self.discovered_peers: typing.Dict['KademliaPeer', typing.Set['KademliaPeer']] = defaultdict(set)
async def send_probe(self, peer: 'KademliaPeer') -> FindValueResponse:
log.debug("probe %s:%d (%s) for VALUE %s",
peer.address, peer.udp_port, peer.node_id.hex()[:8], self.key.hex()[:8])
page = self.peer_pages[peer]
response = await self.protocol.get_rpc_peer(peer).find_value(self.key, page=page)
parsed = FindValueResponse(self.key, response)
if not parsed.found:
return parsed
already_known = len(self.discovered_peers[peer])
decoded_peers = set()
for compact_addr in parsed.found_compact_addresses:
try:
decoded_peers.add(decode_tcp_peer_from_compact_address(compact_addr))
except ValueError:
log.warning("misbehaving peer %s:%i returned invalid peer for blob",
peer.address, peer.udp_port)
self.peer_manager.report_failure(peer.address, peer.udp_port)
parsed.found_compact_addresses.clear()
return parsed
self.discovered_peers[peer].update(decoded_peers)
log.debug("probed %s:%i page %i, %i known", peer.address, peer.udp_port, page,
already_known + len(parsed.found_compact_addresses))
if len(self.discovered_peers[peer]) != already_known + len(parsed.found_compact_addresses):
log.warning("misbehaving peer %s:%i returned duplicate peers for blob", peer.address, peer.udp_port)
elif len(parsed.found_compact_addresses) >= constants.K and self.peer_pages[peer] < parsed.pages:
# the peer returned a full page and indicates it has more
self.peer_pages[peer] += 1
if peer in self.contacted:
# the peer must be removed from self.contacted so that it will be probed for the next page
self.contacted.remove(peer)
return parsed
def check_result_ready(self, response: FindValueResponse):
if response.found:
blob_peers = [decode_tcp_peer_from_compact_address(compact_addr)
for compact_addr in response.found_compact_addresses]
to_yield = []
for blob_peer in blob_peers:
if blob_peer not in self.blob_peers:
self.blob_peers.add(blob_peer)
to_yield.append(blob_peer)
if to_yield:
self.iteration_queue.put_nowait(to_yield)
def get_initial_result(self) -> typing.List['KademliaPeer']:
if self.protocol.data_store.has_peers_for_blob(self.key):
return self.protocol.data_store.get_peers_for_blob(self.key)
return []