256 lines
9.0 KiB
Rust
256 lines
9.0 KiB
Rust
use crate::{error, NetworkConfig};
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/// This manages the discovery and management of peers.
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///
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/// Currently using Kademlia for peer discovery.
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///
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use futures::prelude::*;
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use libp2p::core::swarm::{
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ConnectedPoint, NetworkBehaviour, NetworkBehaviourAction, PollParameters,
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};
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use libp2p::core::{identity::Keypair, Multiaddr, PeerId, ProtocolsHandler};
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use libp2p::discv5::{Discv5, Discv5Event};
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use libp2p::enr::{Enr, EnrBuilder, NodeId};
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use libp2p::multiaddr::Protocol;
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use slog::{debug, error, info, o, warn};
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use std::collections::HashSet;
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use std::time::{Duration, Instant};
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use tokio::io::{AsyncRead, AsyncWrite};
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use tokio_timer::Delay;
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/// Maximum seconds before searching for extra peers.
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const MAX_TIME_BETWEEN_PEER_SEARCHES: u64 = 60;
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/// Lighthouse discovery behaviour. This provides peer management and discovery using the Discv5
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/// libp2p protocol.
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pub struct Discovery<TSubstream> {
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/// The peers currently connected to libp2p streams.
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connected_peers: HashSet<PeerId>,
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/// The target number of connected peers on the libp2p interface.
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max_peers: usize,
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/// The delay between peer discovery searches.
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peer_discovery_delay: Delay,
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/// Tracks the last discovery delay. The delay is doubled each round until the max
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/// time is reached.
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past_discovery_delay: u64,
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/// The TCP port for libp2p. Used to convert an updated IP address to a multiaddr. Note: This
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/// assumes that the external TCP port is the same as the internal TCP port if behind a NAT.
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//TODO: Improve NAT handling limit the above restriction
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tcp_port: u16,
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/// The discovery behaviour used to discover new peers.
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discovery: Discv5<TSubstream>,
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/// Logger for the discovery behaviour.
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log: slog::Logger,
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}
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impl<TSubstream> Discovery<TSubstream> {
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pub fn new(
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local_key: &Keypair,
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net_conf: &NetworkConfig,
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log: &slog::Logger,
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) -> error::Result<Self> {
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let log = log.new(o!("Service" => "Libp2p-Discovery"));
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// Build the local ENR.
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// The first TCP listening address is used for the ENR record. This will inform our peers to
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// connect to this TCP port and establish libp2p streams.
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// Note: Discovery should update the ENR record's IP to the external IP as seen by the
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// majority of our peers.
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let tcp_multiaddr = net_conf
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.listen_addresses
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.iter()
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.filter(|a| {
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if let Some(Protocol::Tcp(_)) = a.iter().last() {
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true
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} else {
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false
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}
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})
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.next()
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.ok_or_else(|| "No valid TCP addresses")?;
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let ip: std::net::IpAddr = match tcp_multiaddr.iter().next() {
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Some(Protocol::Ip4(ip)) => ip.into(),
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Some(Protocol::Ip6(ip)) => ip.into(),
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_ => {
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error!(log, "Multiaddr has an invalid IP address");
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return Err(format!("Invalid IP Address: {}", tcp_multiaddr).into());
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}
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};
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let tcp_port = match tcp_multiaddr.iter().last() {
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Some(Protocol::Tcp(tcp)) => tcp,
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_ => unreachable!(),
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};
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let local_enr = EnrBuilder::new()
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.ip(ip.into())
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.tcp(tcp_port)
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.udp(net_conf.discovery_port)
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.build(&local_key)
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.map_err(|e| format!("Could not build Local ENR: {:?}", e))?;
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info!(log, "Local ENR: {}", local_enr.to_base64());
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let mut discovery = Discv5::new(local_enr, local_key.clone(), net_conf.discovery_address)
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.map_err(|e| format!("Discv5 service failed: {:?}", e))?;
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// Add bootnodes to routing table
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for bootnode_enr in net_conf.boot_nodes.clone() {
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discovery.add_enr(bootnode_enr);
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}
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Ok(Self {
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connected_peers: HashSet::new(),
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max_peers: net_conf.max_peers,
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peer_discovery_delay: Delay::new(Instant::now()),
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past_discovery_delay: 1,
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tcp_port,
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discovery,
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log,
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})
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}
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/// Manually search for peers. This restarts the discovery round, sparking multiple rapid
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/// queries.
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pub fn discover_peers(&mut self) {
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self.past_discovery_delay = 1;
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self.find_peers();
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}
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/// Add an Enr to the routing table of the discovery mechanism.
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pub fn add_enr(&mut self, enr: Enr) {
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self.discovery.add_enr(enr);
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}
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/// Search for new peers using the underlying discovery mechanism.
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fn find_peers(&mut self) {
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// pick a random NodeId
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let random_node = NodeId::random();
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debug!(self.log, "Searching for peers...");
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self.discovery.find_node(random_node);
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// update the time until next discovery
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let delay = {
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if self.past_discovery_delay < MAX_TIME_BETWEEN_PEER_SEARCHES {
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self.past_discovery_delay *= 2;
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self.past_discovery_delay
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} else {
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MAX_TIME_BETWEEN_PEER_SEARCHES
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}
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};
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self.peer_discovery_delay
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.reset(Instant::now() + Duration::from_secs(delay));
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}
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}
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// Redirect all behaviour events to underlying discovery behaviour.
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impl<TSubstream> NetworkBehaviour for Discovery<TSubstream>
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where
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TSubstream: AsyncRead + AsyncWrite,
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{
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type ProtocolsHandler = <Discv5<TSubstream> as NetworkBehaviour>::ProtocolsHandler;
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type OutEvent = <Discv5<TSubstream> as NetworkBehaviour>::OutEvent;
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fn new_handler(&mut self) -> Self::ProtocolsHandler {
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NetworkBehaviour::new_handler(&mut self.discovery)
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}
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fn addresses_of_peer(&mut self, peer_id: &PeerId) -> Vec<Multiaddr> {
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// Let discovery track possible known peers.
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self.discovery.addresses_of_peer(peer_id)
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}
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fn inject_connected(&mut self, peer_id: PeerId, _endpoint: ConnectedPoint) {
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self.connected_peers.insert(peer_id);
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}
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fn inject_disconnected(&mut self, peer_id: &PeerId, _endpoint: ConnectedPoint) {
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self.connected_peers.remove(peer_id);
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}
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fn inject_replaced(
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&mut self,
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_peer_id: PeerId,
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_closed: ConnectedPoint,
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_opened: ConnectedPoint,
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) {
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// discv5 doesn't implement
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}
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fn inject_node_event(
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&mut self,
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_peer_id: PeerId,
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_event: <Self::ProtocolsHandler as ProtocolsHandler>::OutEvent,
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) {
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// discv5 doesn't implement
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}
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fn poll(
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&mut self,
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params: &mut PollParameters,
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) -> Async<
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NetworkBehaviourAction<
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<Self::ProtocolsHandler as ProtocolsHandler>::InEvent,
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Self::OutEvent,
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>,
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> {
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// search of peers if it is time
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loop {
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match self.peer_discovery_delay.poll() {
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Ok(Async::Ready(_)) => {
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self.find_peers();
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}
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Ok(Async::NotReady) => break,
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Err(e) => {
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warn!(self.log, "Discovery peer search failed: {:?}", e);
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}
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}
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}
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// Poll discovery
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loop {
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match self.discovery.poll(params) {
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Async::Ready(NetworkBehaviourAction::GenerateEvent(event)) => {
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match event {
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Discv5Event::Discovered(enr) => {
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debug!(self.log, "Discv5: Peer discovered"; "Peer"=> format!("{:?}", enr.peer_id()), "Addresses" => format!("{:?}", enr.multiaddr()));
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let peer_id = enr.peer_id();
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// if we need more peers, attempt a connection
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if self.connected_peers.len() < self.max_peers
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&& self.connected_peers.get(&peer_id).is_none()
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{
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return Async::Ready(NetworkBehaviourAction::DialPeer { peer_id });
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}
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}
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Discv5Event::SocketUpdated(socket) => {
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info!(self.log, "Address updated"; "IP" => format!("{}",socket.ip()));
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let mut address = Multiaddr::from(socket.ip());
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address.push(Protocol::Tcp(self.tcp_port));
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return Async::Ready(NetworkBehaviourAction::ReportObservedAddr {
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address,
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});
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}
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Discv5Event::FindNodeResult { closer_peers, .. } => {
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debug!(self.log, "Discv5 query found {} peers", closer_peers.len());
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if closer_peers.is_empty() {
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debug!(self.log, "Discv5 random query yielded empty results");
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}
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}
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_ => {}
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}
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}
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// discv5 does not output any other NetworkBehaviourAction
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Async::Ready(_) => {}
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Async::NotReady => break,
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}
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}
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Async::NotReady
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}
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}
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