223 lines
7.9 KiB
Python
223 lines
7.9 KiB
Python
import asyncio
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from libp2p.protocol_muxer.multiselect_client import MultiselectClient
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from libp2p.protocol_muxer.multiselect import Multiselect
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from libp2p.peer.id import id_b58_decode
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from .network_interface import INetwork
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from .notifee_interface import INotifee
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from .stream.net_stream import NetStream
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from .connection.raw_connection import RawConnection
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class Swarm(INetwork):
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# pylint: disable=too-many-instance-attributes, cell-var-from-loop
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def __init__(self, peer_id, peerstore, upgrader):
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self.self_id = peer_id
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self.peerstore = peerstore
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self.upgrader = upgrader
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self.connections = dict()
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self.listeners = dict()
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self.stream_handlers = dict()
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self.transport = None
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# Protocol muxing
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self.multiselect = Multiselect()
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self.multiselect_client = MultiselectClient()
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# Create Notifee array
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self.notifees = []
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# Create generic protocol handler
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self.generic_protocol_handler = create_generic_protocol_handler(self)
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def get_peer_id(self):
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return self.self_id
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def set_stream_handler(self, protocol_id, stream_handler):
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"""
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:param protocol_id: protocol id used on stream
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:param stream_handler: a stream handler instance
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:return: true if successful
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"""
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self.multiselect.add_handler(protocol_id, stream_handler)
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return True
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async def dial_peer(self, peer_id):
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"""
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dial_peer try to create a connection to peer_id
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:param peer_id: peer if we want to dial
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:raises SwarmException: raised when no address if found for peer_id
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:return: muxed connection
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"""
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# Get peer info from peer store
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addrs = self.peerstore.addrs(peer_id)
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if not addrs:
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raise SwarmException("No known addresses to peer")
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# TODO: define logic to choose which address to use, or try them all ?
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multiaddr = addrs[0]
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if peer_id in self.connections:
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# If muxed connection already exists for peer_id,
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# set muxed connection equal to existing muxed connection
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muxed_conn = self.connections[peer_id]
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else:
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# Dial peer (connection to peer does not yet exist)
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# Transport dials peer (gets back a raw conn)
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raw_conn = await self.transport.dial(multiaddr, self.self_id)
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# Per, https://discuss.libp2p.io/t/multistream-security/130, we first secure
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# the conn and then mux the conn
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secured_conn = await self.upgrader.upgrade_security(raw_conn, peer_id, True)
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muxed_conn = self.upgrader.upgrade_connection(secured_conn, \
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self.generic_protocol_handler, peer_id)
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# Store muxed connection in connections
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self.connections[peer_id] = muxed_conn
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# Call notifiers since event occurred
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for notifee in self.notifees:
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await notifee.connected(self, muxed_conn)
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return muxed_conn
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async def new_stream(self, peer_id, protocol_ids):
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"""
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:param peer_id: peer_id of destination
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:param protocol_id: protocol id
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:return: net stream instance
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"""
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# Get peer info from peer store
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addrs = self.peerstore.addrs(peer_id)
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if not addrs:
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raise SwarmException("No known addresses to peer")
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multiaddr = addrs[0]
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muxed_conn = await self.dial_peer(peer_id)
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# Use muxed conn to open stream, which returns
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# a muxed stream
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# TODO: Remove protocol id from being passed into muxed_conn
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muxed_stream = await muxed_conn.open_stream(protocol_ids[0], multiaddr)
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# Perform protocol muxing to determine protocol to use
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selected_protocol = await self.multiselect_client.select_one_of(protocol_ids, muxed_stream)
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# Create a net stream with the selected protocol
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net_stream = NetStream(muxed_stream)
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net_stream.set_protocol(selected_protocol)
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# Call notifiers since event occurred
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for notifee in self.notifees:
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await notifee.opened_stream(self, net_stream)
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return net_stream
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async def listen(self, *args):
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"""
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:param *args: one or many multiaddrs to start listening on
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:return: true if at least one success
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For each multiaddr in args
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Check if a listener for multiaddr exists already
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If listener already exists, continue
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Otherwise:
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Capture multiaddr in conn handler
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Have conn handler delegate to stream handler
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Call listener listen with the multiaddr
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Map multiaddr to listener
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"""
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for multiaddr in args:
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if str(multiaddr) in self.listeners:
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return True
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async def conn_handler(reader, writer):
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# Read in first message (should be peer_id of initiator) and ack
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peer_id = id_b58_decode((await reader.read(1024)).decode())
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writer.write("received peer id".encode())
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await writer.drain()
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# Upgrade reader/write to a net_stream and pass \
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# to appropriate stream handler (using multiaddr)
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raw_conn = RawConnection(multiaddr.value_for_protocol('ip4'),
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multiaddr.value_for_protocol('tcp'), reader, writer, False)
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# Per, https://discuss.libp2p.io/t/multistream-security/130, we first secure
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# the conn and then mux the conn
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secured_conn = await self.upgrader.upgrade_security(raw_conn, peer_id, False)
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muxed_conn = self.upgrader.upgrade_connection(secured_conn, \
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self.generic_protocol_handler, peer_id)
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# Store muxed_conn with peer id
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self.connections[peer_id] = muxed_conn
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# Call notifiers since event occurred
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for notifee in self.notifees:
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await notifee.connected(self, muxed_conn)
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try:
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# Success
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listener = self.transport.create_listener(conn_handler)
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self.listeners[str(multiaddr)] = listener
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await listener.listen(multiaddr)
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# Call notifiers since event occurred
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for notifee in self.notifees:
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await notifee.listen(self, multiaddr)
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return True
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except IOError:
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# Failed. Continue looping.
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print("Failed to connect to: " + str(multiaddr))
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# No multiaddr succeeded
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return False
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def notify(self, notifee):
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"""
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:param notifee: object implementing Notifee interface
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:return: true if notifee registered successfully, false otherwise
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"""
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if isinstance(notifee, INotifee):
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self.notifees.append(notifee)
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return True
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return False
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def add_transport(self, transport):
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# TODO: Support more than one transport
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self.transport = transport
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def create_generic_protocol_handler(swarm):
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"""
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Create a generic protocol handler from the given swarm. We use swarm
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to extract the multiselect module so that generic_protocol_handler
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can use multiselect when generic_protocol_handler is called
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from a different class
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"""
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multiselect = swarm.multiselect
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async def generic_protocol_handler(muxed_stream):
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# Perform protocol muxing to determine protocol to use
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protocol, handler = await multiselect.negotiate(muxed_stream)
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net_stream = NetStream(muxed_stream)
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net_stream.set_protocol(protocol)
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# Call notifiers since event occurred
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for notifee in swarm.notifees:
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await notifee.opened_stream(swarm, net_stream)
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# Give to stream handler
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asyncio.ensure_future(handler(net_stream))
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return generic_protocol_handler
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class SwarmException(Exception):
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pass
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