import asyncio from libp2p.protocol_muxer.multiselect_client import MultiselectClient from libp2p.protocol_muxer.multiselect import Multiselect from libp2p.peer.id import id_b58_decode from .network_interface import INetwork from .notifee_interface import INotifee from .stream.net_stream import NetStream from .connection.raw_connection import RawConnection class Swarm(INetwork): # pylint: disable=too-many-instance-attributes, cell-var-from-loop def __init__(self, peer_id, peerstore, upgrader): self.self_id = peer_id self.peerstore = peerstore self.upgrader = upgrader self.connections = dict() self.listeners = dict() self.stream_handlers = dict() self.transport = None # Protocol muxing self.multiselect = Multiselect() self.multiselect_client = MultiselectClient() # Create Notifee array self.notifees = [] # Create generic protocol handler self.generic_protocol_handler = create_generic_protocol_handler(self) def get_peer_id(self): return self.self_id def set_stream_handler(self, protocol_id, stream_handler): """ :param protocol_id: protocol id used on stream :param stream_handler: a stream handler instance :return: true if successful """ self.multiselect.add_handler(protocol_id, stream_handler) return True async def dial_peer(self, peer_id): """ dial_peer try to create a connection to peer_id :param peer_id: peer if we want to dial :raises SwarmException: raised when no address if found for peer_id :return: muxed connection """ # Get peer info from peer store addrs = self.peerstore.addrs(peer_id) if not addrs: raise SwarmException("No known addresses to peer") # TODO: define logic to choose which address to use, or try them all ? multiaddr = addrs[0] if peer_id in self.connections: # If muxed connection already exists for peer_id, # set muxed connection equal to existing muxed connection muxed_conn = self.connections[peer_id] else: # Dial peer (connection to peer does not yet exist) # Transport dials peer (gets back a raw conn) raw_conn = await self.transport.dial(multiaddr, self.self_id) # Use upgrader to upgrade raw conn to muxed conn muxed_conn = self.upgrader.upgrade_connection(raw_conn, self.generic_protocol_handler) # Store muxed connection in connections self.connections[peer_id] = muxed_conn # Call notifiers since event occurred for notifee in self.notifees: await notifee.connected(self, muxed_conn) return muxed_conn async def new_stream(self, peer_id, protocol_ids): """ :param peer_id: peer_id of destination :param protocol_id: protocol id :return: net stream instance """ # Get peer info from peer store addrs = self.peerstore.addrs(peer_id) if not addrs: raise SwarmException("No known addresses to peer") multiaddr = addrs[0] muxed_conn = await self.dial_peer(peer_id) # Use muxed conn to open stream, which returns # a muxed stream # TODO: Remove protocol id from being passed into muxed_conn muxed_stream = await muxed_conn.open_stream(protocol_ids[0], multiaddr) # Perform protocol muxing to determine protocol to use selected_protocol = await self.multiselect_client.select_one_of(protocol_ids, muxed_stream) # Create a net stream with the selected protocol net_stream = NetStream(muxed_stream) net_stream.set_protocol(selected_protocol) # Call notifiers since event occurred for notifee in self.notifees: await notifee.opened_stream(self, net_stream) return net_stream async def listen(self, *args): """ :param *args: one or many multiaddrs to start listening on :return: true if at least one success For each multiaddr in args 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 multiaddr in args: if str(multiaddr) in self.listeners: return True async def conn_handler(reader, writer): # Read in first message (should be peer_id of initiator) and ack peer_id = id_b58_decode((await reader.read(1024)).decode()) writer.write("received peer id".encode()) await writer.drain() # Upgrade reader/write to a net_stream and pass \ # to appropriate stream handler (using multiaddr) raw_conn = RawConnection(multiaddr.value_for_protocol('ip4'), multiaddr.value_for_protocol('tcp'), reader, writer, False) muxed_conn = self.upgrader.upgrade_connection(raw_conn, \ self.generic_protocol_handler) # Store muxed_conn with peer id self.connections[peer_id] = muxed_conn # Call notifiers since event occurred for notifee in self.notifees: await notifee.connected(self, muxed_conn) try: # Success listener = self.transport.create_listener(conn_handler) self.listeners[str(multiaddr)] = listener await listener.listen(multiaddr) # Call notifiers since event occurred for notifee in self.notifees: await notifee.listen(self, multiaddr) return True except IOError: # Failed. Continue looping. print("Failed to connect to: " + str(multiaddr)) # No multiaddr succeeded return False def notify(self, notifee): """ :param notifee: object implementing Notifee interface """ if isinstance(notifee, INotifee): self.notifees.append(notifee) def add_transport(self, transport): # TODO: Support more than one transport self.transport = transport def create_generic_protocol_handler(swarm): """ Create a generic protocol handler from the given swarm. We use swarm to extract the multiselect module so that generic_protocol_handler can use multiselect when generic_protocol_handler is called from a different class """ multiselect = swarm.multiselect async def generic_protocol_handler(muxed_stream): # Perform protocol muxing to determine protocol to use _, handler = await multiselect.negotiate(muxed_stream) # Call notifiers since event occurred for notifee in swarm.notifees: await notifee.opened_stream(swarm, muxed_stream) # Give to stream handler asyncio.ensure_future(handler(muxed_stream)) return generic_protocol_handler class SwarmException(Exception): pass