import asyncio import logging from typing import Dict, List, Optional, Sequence from multiaddr import Multiaddr from libp2p.network.connection.net_connection_interface import INetConn from libp2p.peer.id import ID from libp2p.peer.peerstore import PeerStoreError from libp2p.peer.peerstore_interface import IPeerStore from libp2p.routing.interfaces import IPeerRouting from libp2p.stream_muxer.abc import IMuxedConn from libp2p.transport.exceptions import MuxerUpgradeFailure, SecurityUpgradeFailure from libp2p.transport.listener_interface import IListener from libp2p.transport.transport_interface import ITransport from libp2p.transport.upgrader import TransportUpgrader from libp2p.typing import StreamHandlerFn, TProtocol from .connection.raw_connection import RawConnection from .connection.swarm_connection import SwarmConn from .exceptions import SwarmException from .network_interface import INetwork from .notifee_interface import INotifee from .stream.net_stream_interface import INetStream logger = logging.getLogger("libp2p.network.swarm") logger.setLevel(logging.DEBUG) class Swarm(INetwork): self_id: ID peerstore: IPeerStore upgrader: TransportUpgrader transport: ITransport router: IPeerRouting # TODO: Connection and `peer_id` are 1-1 mapping in our implementation, # whereas in Go one `peer_id` may point to multiple connections. connections: Dict[ID, INetConn] listeners: Dict[str, IListener] common_stream_handler: Optional[StreamHandlerFn] notifees: List[INotifee] def __init__( self, peer_id: ID, peerstore: IPeerStore, upgrader: TransportUpgrader, transport: ITransport, router: IPeerRouting, ): self.self_id = peer_id self.peerstore = peerstore self.upgrader = upgrader self.transport = transport self.router = router self.connections = dict() self.listeners = dict() # Create Notifee array self.notifees = [] self.common_stream_handler = None def get_peer_id(self) -> ID: return self.self_id def set_stream_handler(self, stream_handler: StreamHandlerFn) -> None: self.common_stream_handler = stream_handler async def dial_peer(self, peer_id: ID) -> INetConn: """ dial_peer try to create a connection to peer_id :param peer_id: peer if we want to dial :raises SwarmException: raised when an error occurs :return: muxed connection """ if peer_id in self.connections: # If muxed connection already exists for peer_id, # set muxed connection equal to existing muxed connection return self.connections[peer_id] logger.debug("attempting to dial peer %s", peer_id) try: # Get peer info from peer store addrs = self.peerstore.addrs(peer_id) except PeerStoreError: raise SwarmException(f"No known addresses to peer {peer_id}") if not addrs: raise SwarmException(f"No known addresses to peer {peer_id}") if not self.router: multiaddr = addrs[0] else: multiaddr = self.router.find_peer(peer_id) # Dial peer (connection to peer does not yet exist) # Transport dials peer (gets back a raw conn) raw_conn = await self.transport.dial(multiaddr) logger.debug("dialed peer %s over base transport", peer_id) # Per, https://discuss.libp2p.io/t/multistream-security/130, we first secure # the conn and then mux the conn try: secured_conn = await self.upgrader.upgrade_security(raw_conn, peer_id, True) except SecurityUpgradeFailure as error: error_msg = "fail to upgrade security for peer %s" logger.debug(error_msg, peer_id) await raw_conn.close() raise SwarmException(error_msg % peer_id) from error logger.debug("upgraded security for peer %s", peer_id) try: muxed_conn = await self.upgrader.upgrade_connection(secured_conn, peer_id) except MuxerUpgradeFailure as error: error_msg = "fail to upgrade mux for peer %s" logger.debug(error_msg, peer_id) await secured_conn.close() raise SwarmException(error_msg % peer_id) from error logger.debug("upgraded mux for peer %s", peer_id) swarm_conn = await self.add_conn(muxed_conn) logger.debug("successfully dialed peer %s", peer_id) return swarm_conn async def new_stream( self, peer_id: ID, protocol_ids: Sequence[TProtocol] ) -> INetStream: """ :param peer_id: peer_id of destination :param protocol_id: protocol id :return: net stream instance """ logger.debug( "attempting to open a stream to peer %s, over one of the protocols %s", peer_id, protocol_ids, ) swarm_conn = await self.dial_peer(peer_id) net_stream = await swarm_conn.new_stream() logger.debug("successfully opened a stream to peer %s", peer_id) return net_stream async def listen(self, *multiaddrs: Multiaddr) -> bool: """ :param multiaddrs: one or many multiaddrs to start listening on :return: true if at least one success For each multiaddr Check if a listener for multiaddr exists already If listener already exists, continue Otherwise: Capture multiaddr in conn handler Have conn handler delegate to stream handler Call listener listen with the multiaddr Map multiaddr to listener """ for maddr in multiaddrs: if str(maddr) in self.listeners: return True async def conn_handler( reader: asyncio.StreamReader, writer: asyncio.StreamWriter ) -> None: connection_info = writer.get_extra_info("peername") # TODO make a proper multiaddr peer_addr = f"/ip4/{connection_info[0]}/tcp/{connection_info[1]}" logger.debug("inbound connection at %s", peer_addr) # logger.debug("inbound connection request", peer_id) raw_conn = RawConnection(reader, writer, False) # Per, https://discuss.libp2p.io/t/multistream-security/130, we first secure # the conn and then mux the conn try: # FIXME: This dummy `ID(b"")` for the remote peer is useless. secured_conn = await self.upgrader.upgrade_security( raw_conn, ID(b""), False ) except SecurityUpgradeFailure as error: error_msg = "fail to upgrade security for peer at %s" logger.debug(error_msg, peer_addr) await raw_conn.close() raise SwarmException(error_msg % peer_addr) from error peer_id = secured_conn.get_remote_peer() logger.debug("upgraded security for peer at %s", peer_addr) logger.debug("identified peer at %s as %s", peer_addr, peer_id) try: muxed_conn = await self.upgrader.upgrade_connection( secured_conn, peer_id ) except MuxerUpgradeFailure as error: error_msg = "fail to upgrade mux for peer %s" logger.debug(error_msg, peer_id) await secured_conn.close() raise SwarmException(error_msg % peer_id) from error logger.debug("upgraded mux for peer %s", peer_id) await self.add_conn(muxed_conn) logger.debug("successfully opened connection to peer %s", peer_id) try: # Success listener = self.transport.create_listener(conn_handler) self.listeners[str(maddr)] = listener await listener.listen(maddr) # Call notifiers since event occurred for notifee in self.notifees: await notifee.listen(self, maddr) return True except IOError: # Failed. Continue looping. logger.debug("fail to listen on: " + str(maddr)) # No maddr succeeded return False def notify(self, notifee: INotifee) -> bool: """ :param notifee: object implementing Notifee interface :return: true if notifee registered successfully, false otherwise """ if isinstance(notifee, INotifee): self.notifees.append(notifee) return True return False def add_router(self, router: IPeerRouting) -> None: self.router = router async def close(self) -> None: # TODO: Prevent from new listeners and conns being added. # Reference: https://github.com/libp2p/go-libp2p-swarm/blob/8be680aef8dea0a4497283f2f98470c2aeae6b65/swarm.go#L124-L134 # noqa: E501 # Close listeners await asyncio.gather( *[listener.close() for listener in self.listeners.values()] ) # Close connections await asyncio.gather( *[connection.close() for connection in self.connections.values()] ) logger.debug("swarm successfully closed") async def close_peer(self, peer_id: ID) -> None: if peer_id not in self.connections: return # TODO: Should be changed to close multisple connections, # if we have several connections per peer in the future. connection = self.connections[peer_id] await connection.close() logger.debug("successfully close the connection to peer %s", peer_id) async def add_conn(self, muxed_conn: IMuxedConn) -> SwarmConn: """ Add a `IMuxedConn` to `Swarm` as a `SwarmConn`, notify "connected", and start to monitor the connection for its new streams and disconnection. """ swarm_conn = SwarmConn(muxed_conn, self) # Store muxed_conn with peer id self.connections[muxed_conn.peer_id] = swarm_conn # Call notifiers since event occurred for notifee in self.notifees: await notifee.connected(self, swarm_conn) await swarm_conn.start() return swarm_conn def remove_conn(self, swarm_conn: SwarmConn) -> None: """ Simply remove the connection from Swarm's records, without closing the connection. """ peer_id = swarm_conn.conn.peer_id if peer_id not in self.connections: return # TODO: Should be changed to remove the exact connection, # if we have several connections per peer in the future. del self.connections[peer_id]