import typing import asyncio import logging import ipaddress from binascii import hexlify from dataclasses import dataclass, field from functools import lru_cache from lbry.dht import constants from lbry.dht.serialization.datagram import make_compact_address, make_compact_ip, decode_compact_address log = logging.getLogger(__name__) @lru_cache(1024) def make_kademlia_peer(node_id: typing.Optional[bytes], address: typing.Optional[str], udp_port: typing.Optional[int] = None, tcp_port: typing.Optional[int] = None, allow_localhost: bool = False) -> 'KademliaPeer': return KademliaPeer(address, node_id, udp_port, tcp_port=tcp_port, allow_localhost=allow_localhost) # the ipaddress module does not show these subnets as reserved carrier_grade_NAT_subnet = ipaddress.ip_network('100.64.0.0/10') ip4_to_6_relay_subnet = ipaddress.ip_network('192.88.99.0/24') ALLOW_LOCALHOST = False def is_valid_public_ipv4(address, allow_localhost: bool = False): allow_localhost = bool(allow_localhost or ALLOW_LOCALHOST) try: parsed_ip = ipaddress.ip_address(address) if parsed_ip.is_loopback and allow_localhost: return True return not any((parsed_ip.version != 4, parsed_ip.is_unspecified, parsed_ip.is_link_local, parsed_ip.is_loopback, parsed_ip.is_multicast, parsed_ip.is_reserved, parsed_ip.is_private, parsed_ip.is_reserved, carrier_grade_NAT_subnet.supernet_of(ipaddress.ip_network(f"{address}/32")), ip4_to_6_relay_subnet.supernet_of(ipaddress.ip_network(f"{address}/32")))) except ipaddress.AddressValueError: return False class PeerManager: def __init__(self, loop: asyncio.AbstractEventLoop): self._loop = loop self._rpc_failures: typing.Dict[ typing.Tuple[str, int], typing.Tuple[typing.Optional[float], typing.Optional[float]] ] = {} self._last_replied: typing.Dict[typing.Tuple[str, int], float] = {} self._last_sent: typing.Dict[typing.Tuple[str, int], float] = {} self._last_requested: typing.Dict[typing.Tuple[str, int], float] = {} self._node_id_mapping: typing.Dict[typing.Tuple[str, int], bytes] = {} self._node_id_reverse_mapping: typing.Dict[bytes, typing.Tuple[str, int]] = {} self._node_tokens: typing.Dict[bytes, (float, bytes)] = {} def reset(self): for statistic in (self._rpc_failures, self._last_replied, self._last_sent, self._last_requested): statistic.clear() def report_failure(self, address: str, udp_port: int): now = self._loop.time() _, previous = self._rpc_failures.pop((address, udp_port), (None, None)) self._rpc_failures[(address, udp_port)] = (previous, now) def report_last_sent(self, address: str, udp_port: int): now = self._loop.time() self._last_sent[(address, udp_port)] = now def report_last_replied(self, address: str, udp_port: int): now = self._loop.time() self._last_replied[(address, udp_port)] = now def report_last_requested(self, address: str, udp_port: int): now = self._loop.time() self._last_requested[(address, udp_port)] = now def clear_token(self, node_id: bytes): self._node_tokens.pop(node_id, None) def update_token(self, node_id: bytes, token: bytes): now = self._loop.time() self._node_tokens[node_id] = (now, token) def get_node_token(self, node_id: bytes) -> typing.Optional[bytes]: ts, token = self._node_tokens.get(node_id, (0, None)) if ts and ts > self._loop.time() - constants.TOKEN_SECRET_REFRESH_INTERVAL: return token def get_last_replied(self, address: str, udp_port: int) -> typing.Optional[float]: return self._last_replied.get((address, udp_port)) def update_contact_triple(self, node_id: bytes, address: str, udp_port: int): """ Update the mapping of node_id -> address tuple and that of address tuple -> node_id This is to handle peers changing addresses and ids while assuring that the we only ever have one node id / address tuple mapped to each other """ if (address, udp_port) in self._node_id_mapping: self._node_id_reverse_mapping.pop(self._node_id_mapping.pop((address, udp_port))) if node_id in self._node_id_reverse_mapping: self._node_id_mapping.pop(self._node_id_reverse_mapping.pop(node_id)) self._node_id_mapping[(address, udp_port)] = node_id self._node_id_reverse_mapping[node_id] = (address, udp_port) def prune(self): # TODO: periodically call this now = self._loop.time() to_pop = [] for (address, udp_port), (_, last_failure) in self._rpc_failures.items(): if last_failure and last_failure < now - constants.RPC_ATTEMPTS_PRUNING_WINDOW: to_pop.append((address, udp_port)) while to_pop: del self._rpc_failures[to_pop.pop()] to_pop = [] for node_id, (age, token) in self._node_tokens.items(): if age < now - constants.TOKEN_SECRET_REFRESH_INTERVAL: to_pop.append(node_id) while to_pop: del self._node_tokens[to_pop.pop()] def contact_triple_is_good(self, node_id: bytes, address: str, udp_port: int): """ :return: False if peer is bad, None if peer is unknown, or True if peer is good """ delay = self._loop.time() - constants.CHECK_REFRESH_INTERVAL # fixme: find a way to re-enable that without breaking other parts # if node_id not in self._node_id_reverse_mapping or (address, udp_port) not in self._node_id_mapping: # return # addr_tup = (address, udp_port) # if self._node_id_reverse_mapping[node_id] != addr_tup or self._node_id_mapping[addr_tup] != node_id: # return previous_failure, most_recent_failure = self._rpc_failures.get((address, udp_port), (None, None)) last_requested = self._last_requested.get((address, udp_port)) last_replied = self._last_replied.get((address, udp_port)) if node_id is None: return None if most_recent_failure and last_replied: if delay < last_replied > most_recent_failure: return True elif last_replied > most_recent_failure: return return False elif previous_failure and most_recent_failure and most_recent_failure > delay: return False elif last_replied and last_replied > delay: return True elif last_requested and last_requested > delay: return None return def peer_is_good(self, peer: 'KademliaPeer'): return self.contact_triple_is_good(peer.node_id, peer.address, peer.udp_port) def decode_tcp_peer_from_compact_address(self, compact_address: bytes) -> 'KademliaPeer': node_id, address, tcp_port = decode_compact_address(compact_address) return make_kademlia_peer(node_id, address, udp_port=None, tcp_port=tcp_port) @dataclass(unsafe_hash=True) class KademliaPeer: address: str = field(hash=True) _node_id: typing.Optional[bytes] = field(hash=True) udp_port: typing.Optional[int] = field(hash=True) tcp_port: typing.Optional[int] = field(compare=False, hash=False) protocol_version: typing.Optional[int] = field(default=1, compare=False, hash=False) allow_localhost: bool = field(default=False, compare=False, hash=False) def __post_init__(self): if self._node_id is not None: if not len(self._node_id) == constants.HASH_LENGTH: raise ValueError("invalid node_id: {}".format(hexlify(self._node_id).decode())) if self.udp_port is not None and not 1 <= self.udp_port <= 65535: raise ValueError("invalid udp port") if self.tcp_port is not None and not 1 <= self.tcp_port <= 65535: raise ValueError("invalid tcp port") if not is_valid_public_ipv4(self.address, self.allow_localhost): raise ValueError(f"invalid ip address: '{self.address}'") def update_tcp_port(self, tcp_port: int): self.tcp_port = tcp_port @property def node_id(self) -> bytes: return self._node_id def compact_address_udp(self) -> bytearray: return make_compact_address(self.node_id, self.address, self.udp_port) def compact_address_tcp(self) -> bytearray: return make_compact_address(self.node_id, self.address, self.tcp_port) def compact_ip(self): return make_compact_ip(self.address)