Files
py-libp2p/libp2p/discovery/mdns/mdns.py
2025-06-25 23:44:32 +05:30

74 lines
1.9 KiB
Python

"""
mDNS-based peer discovery for py-libp2p.
Conforms to https://github.com/libp2p/specs/blob/master/discovery/mdns.md
Uses zeroconf for mDNS broadcast/listen. Async operations use trio.
"""
import logging
from zeroconf import (
Zeroconf,
)
from libp2p.abc import (
INetworkService,
)
from .broadcaster import (
PeerBroadcaster,
)
from .listener import (
PeerListener,
)
from .utils import (
stringGen,
)
logger = logging.getLogger("libp2p.discovery.mdns")
SERVICE_TYPE = "_p2p._udp.local."
MCAST_PORT = 5353
MCAST_ADDR = "224.0.0.251"
class MDNSDiscovery:
"""
mDNS-based peer discovery for py-libp2p, using zeroconf.
Conforms to the libp2p mDNS discovery spec.
"""
def __init__(self, swarm: INetworkService, port: int = 8000):
self.peer_id = str(swarm.get_peer_id())
self.port = port
self.zeroconf = Zeroconf()
self.serviceName = f"{stringGen()}.{SERVICE_TYPE}"
self.peerstore = swarm.peerstore
self.swarm = swarm
self.broadcaster = PeerBroadcaster(
zeroconf=self.zeroconf,
service_type=SERVICE_TYPE,
service_name=self.serviceName,
peer_id=self.peer_id,
port=self.port,
)
self.listener = PeerListener(
zeroconf=self.zeroconf,
peerstore=self.peerstore,
service_type=SERVICE_TYPE,
service_name=self.serviceName,
)
def start(self) -> None:
"""Register this peer and start listening for others."""
logger.debug(
f"Starting mDNS discovery for peer {self.peer_id} on port {self.port}"
)
self.broadcaster.register()
# Listener is started in constructor
def stop(self) -> None:
"""Unregister this peer and clean up zeroconf resources."""
logger.debug("Stopping mDNS discovery")
self.broadcaster.unregister()
self.zeroconf.close()