feat(perf): implement libp2p perf protocol

Implementation of the libp2p perf protocol according to https://github.com/libp2p/specs/pull/478/.

//CC @MarcoPolo  as the author of the specification.

**Don't (yet) expect this to produce reliable performance metrics.**

Pull-Request: #3508.

CHANGELOG.md

@@ -26,6 +26,7 @@
 - [`libp2p-deflate` CHANGELOG](transports/deflate/CHANGELOG.md)
 - [`libp2p-dns` CHANGELOG](transports/dns/CHANGELOG.md)
 - [`libp2p-noise` CHANGELOG](transports/noise/CHANGELOG.md)
+- [`libp2p-perf` CHANGELOG](transports/perf/CHANGELOG.md)
 - [`libp2p-plaintext` CHANGELOG](transports/plaintext/CHANGELOG.md)
 - [`libp2p-pnet` CHANGELOG](transports/pnet/CHANGELOG.md)
 - [`libp2p-quic` CHANGELOG](transports/quic/CHANGELOG.md)

Cargo.lock

@@ -2163,6 +2163,7 @@ dependencies = [
  "libp2p-metrics",
  "libp2p-mplex",
  "libp2p-noise",
+ "libp2p-perf",
  "libp2p-ping",
  "libp2p-plaintext",
  "libp2p-pnet",
@@ -2551,6 +2552,32 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "libp2p-perf"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "async-std",
+ "clap 4.1.8",
+ "env_logger 0.10.0",
+ "futures",
+ "instant",
+ "libp2p-core",
+ "libp2p-dns",
+ "libp2p-identity",
+ "libp2p-noise",
+ "libp2p-plaintext",
+ "libp2p-quic",
+ "libp2p-swarm",
+ "libp2p-swarm-test",
+ "libp2p-tcp",
+ "libp2p-yamux",
+ "log",
+ "rand 0.8.5",
+ "thiserror",
+ "void",
+]
+
 [[package]]
 name = "libp2p-ping"
 version = "0.42.0"

Cargo.toml

@@ -28,6 +28,7 @@ members = [
     "protocols/identify",
     "protocols/kad",
     "protocols/mdns",
+    "protocols/perf",
     "protocols/ping",
     "protocols/relay",
     "protocols/request-response",

libp2p/Cargo.toml

@@ -28,6 +28,7 @@ full = [
     "metrics",
     "mplex",
     "noise",
+    "perf",
     "ping",
     "plaintext",
     "pnet",
@@ -66,6 +67,7 @@ mdns = ["dep:libp2p-mdns"]
 metrics = ["dep:libp2p-metrics"]
 mplex = ["dep:libp2p-mplex"]
 noise = ["dep:libp2p-noise"]
+perf = ["dep:libp2p-perf"]
 ping = ["dep:libp2p-ping", "libp2p-metrics?/ping"]
 plaintext = ["dep:libp2p-plaintext"]
 pnet = ["dep:libp2p-pnet"]
@@ -120,6 +122,7 @@ pin-project = "1.0.0"
 libp2p-deflate = { version = "0.39.0", path = "../transports/deflate", optional = true }
 libp2p-dns = { version = "0.39.0", path = "../transports/dns", optional = true }
 libp2p-mdns = { version = "0.43.0", path = "../protocols/mdns", optional = true }
+libp2p-perf = { version = "0.1.0", path = "../protocols/perf", optional = true }
 libp2p-quic = { version = "0.7.0-alpha.3", path = "../transports/quic", optional = true }
 libp2p-tcp = { version = "0.39.0", path = "../transports/tcp", optional = true }
 libp2p-tls = { version = "0.1.0", path = "../transports/tls", optional = true }

protocols/perf/CHANGELOG.md

@@ -0,0 +1,3 @@
+# 0.1.0 - unreleased
+
+- Initial release.

protocols/perf/Cargo.toml

@@ -0,0 +1,42 @@
+[package]
+name = "libp2p-perf"
+edition = "2021"
+rust-version = "1.64.0"
+description = "libp2p perf protocol implementation"
+version = "0.1.0"
+authors = ["Max Inden <mail@max-inden.de>"]
+license = "MIT"
+repository = "https://github.com/libp2p/rust-libp2p"
+keywords = ["peer-to-peer", "libp2p", "networking"]
+categories = ["network-programming", "asynchronous"]
+
+[dependencies]
+anyhow = "1"
+async-std = { version = "1.9.0", features = ["attributes"] }
+clap = { version = "4.1.6", features = ["derive"] }
+env_logger = "0.10.0"
+futures = "0.3.26"
+instant = "0.1.11"
+libp2p-core = { version = "0.39.0", path = "../../core" }
+libp2p-dns = { version = "0.39.0", path = "../../transports/dns", features = ["async-std"] }
+libp2p-identity = { version = "0.1.0", path = "../../identity" }
+libp2p-noise = { version = "0.42.0", path = "../../transports/noise" }
+libp2p-quic = { version = "0.7.0-alpha.2", path = "../../transports/quic", features = ["async-std"] }
+libp2p-swarm = { version = "0.42.0", path = "../../swarm", features = ["macros", "async-std"] }
+libp2p-swarm-test = { path = "../../swarm-test"}
+libp2p-tcp = { version = "0.39.0", path = "../../transports/tcp", features = ["async-io"] }
+libp2p-yamux = { version = "0.43.0", path = "../../muxers/yamux" }
+log = "0.4"
+thiserror = "1.0"
+void = "1"
+
+[dev-dependencies]
+rand = "0.8"
+libp2p-plaintext = { path = "../../transports/plaintext" }
+
+# Passing arguments to the docsrs builder in order to properly document cfg's.
+# More information: https://docs.rs/about/builds#cross-compiling
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+rustc-args = ["--cfg", "docsrs"]

protocols/perf/Dockerfile

@@ -0,0 +1,22 @@
+# syntax=docker/dockerfile:1.5-labs
+FROM rust:1.67.0 as builder
+
+# Run with access to the target cache to speed up builds
+WORKDIR /workspace
+ADD . .
+RUN --mount=type=cache,target=./target \
+    --mount=type=cache,target=/usr/local/cargo/registry \
+    cargo build --release --package libp2p-perf
+
+RUN --mount=type=cache,target=./target \
+    mv ./target/release/perf-server /usr/local/bin/perf-server
+
+RUN --mount=type=cache,target=./target \
+    mv ./target/release/perf-client /usr/local/bin/perf-client
+
+FROM debian:bullseye-slim
+
+COPY --from=builder /usr/local/bin/perf-server /usr/local/bin/perf-server
+COPY --from=builder /usr/local/bin/perf-client /usr/local/bin/perf-client
+
+ENTRYPOINT [ "perf-server"]

protocols/perf/src/bin/perf-client.rs

@@ -0,0 +1,140 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+use anyhow::{bail, Result};
+use clap::Parser;
+use futures::{future::Either, StreamExt};
+use libp2p_core::{muxing::StreamMuxerBox, transport::OrTransport, upgrade, Multiaddr, Transport};
+use libp2p_dns::DnsConfig;
+use libp2p_identity::PeerId;
+use libp2p_perf::client::RunParams;
+use libp2p_swarm::{SwarmBuilder, SwarmEvent};
+use log::info;
+
+#[derive(Debug, Parser)]
+#[clap(name = "libp2p perf client")]
+struct Opts {
+    #[arg(long)]
+    server_address: Multiaddr,
+}
+
+#[async_std::main]
+async fn main() -> Result<()> {
+    env_logger::Builder::from_env(env_logger::Env::default().default_filter_or("info")).init();
+
+    let opts = Opts::parse();
+
+    info!("Initiating performance tests with {}", opts.server_address);
+
+    // Create a random PeerId
+    let local_key = libp2p_identity::Keypair::generate_ed25519();
+    let local_peer_id = PeerId::from(local_key.public());
+
+    let transport = {
+        let tcp =
+            libp2p_tcp::async_io::Transport::new(libp2p_tcp::Config::default().port_reuse(true))
+                .upgrade(upgrade::Version::V1Lazy)
+                .authenticate(
+                    libp2p_noise::NoiseAuthenticated::xx(&local_key)
+                        .expect("Signing libp2p-noise static DH keypair failed."),
+                )
+                .multiplex(libp2p_yamux::YamuxConfig::default());
+
+        let quic = {
+            let mut config = libp2p_quic::Config::new(&local_key);
+            config.support_draft_29 = true;
+            libp2p_quic::async_std::Transport::new(config)
+        };
+
+        let dns = DnsConfig::system(OrTransport::new(quic, tcp))
+            .await
+            .unwrap();
+
+        dns.map(|either_output, _| match either_output {
+            Either::Left((peer_id, muxer)) => (peer_id, StreamMuxerBox::new(muxer)),
+            Either::Right((peer_id, muxer)) => (peer_id, StreamMuxerBox::new(muxer)),
+        })
+        .boxed()
+    };
+
+    let mut swarm = SwarmBuilder::with_async_std_executor(
+        transport,
+        libp2p_perf::client::Behaviour::default(),
+        local_peer_id,
+    )
+    .substream_upgrade_protocol_override(upgrade::Version::V1Lazy)
+    .build();
+
+    swarm.dial(opts.server_address.clone()).unwrap();
+    let server_peer_id = loop {
+        match swarm.next().await.unwrap() {
+            SwarmEvent::ConnectionEstablished { peer_id, .. } => break peer_id,
+            SwarmEvent::OutgoingConnectionError { peer_id, error } => {
+                bail!("Outgoing connection error to {:?}: {:?}", peer_id, error);
+            }
+            e => panic!("{e:?}"),
+        }
+    };
+
+    info!(
+        "Connection to {} established. Launching benchmarks.",
+        opts.server_address
+    );
+
+    swarm.behaviour_mut().perf(
+        server_peer_id,
+        RunParams {
+            to_send: 10 * 1024 * 1024,
+            to_receive: 10 * 1024 * 1024,
+        },
+    )?;
+
+    let stats = loop {
+        match swarm.next().await.unwrap() {
+            SwarmEvent::ConnectionEstablished {
+                peer_id, endpoint, ..
+            } => {
+                info!("Established connection to {:?} via {:?}", peer_id, endpoint);
+            }
+            SwarmEvent::OutgoingConnectionError { peer_id, error } => {
+                info!("Outgoing connection error to {:?}: {:?}", peer_id, error);
+            }
+            SwarmEvent::Behaviour(libp2p_perf::client::Event { id: _, result }) => break result?,
+            e => panic!("{e:?}"),
+        }
+    };
+
+    let sent_mebibytes = stats.params.to_send as f64 / 1024.0 / 1024.0;
+    let sent_time = (stats.timers.write_done - stats.timers.write_start).as_secs_f64();
+    let sent_bandwidth_mebibit_second = (sent_mebibytes * 8.0) / sent_time;
+
+    let received_mebibytes = stats.params.to_receive as f64 / 1024.0 / 1024.0;
+    let receive_time = (stats.timers.read_done - stats.timers.write_done).as_secs_f64();
+    let receive_bandwidth_mebibit_second = (received_mebibytes * 8.0) / receive_time;
+
+    info!(
+        "Finished run: Sent {sent_mebibytes:.2} MiB in {sent_time:.2} s with \
+         {sent_bandwidth_mebibit_second:.2} MiBit/s and received \
+         {received_mebibytes:.2} MiB in {receive_time:.2} s with \
+         {receive_bandwidth_mebibit_second:.2} MiBit/s",
+    );
+
+    Ok(())
+}

protocols/perf/src/bin/perf-server.rs

@@ -0,0 +1,128 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+use clap::Parser;
+use futures::{future::Either, StreamExt};
+use libp2p_core::{muxing::StreamMuxerBox, transport::OrTransport, upgrade, Transport};
+use libp2p_dns::DnsConfig;
+use libp2p_identity::PeerId;
+use libp2p_swarm::{SwarmBuilder, SwarmEvent};
+use log::{error, info};
+
+#[derive(Debug, Parser)]
+#[clap(name = "libp2p perf server")]
+struct Opts {}
+
+#[async_std::main]
+async fn main() {
+    env_logger::init();
+
+    let _opts = Opts::parse();
+
+    // Create a random PeerId
+    let local_key = libp2p_identity::Keypair::generate_ed25519();
+    let local_peer_id = PeerId::from(local_key.public());
+    println!("Local peer id: {local_peer_id}");
+
+    let transport = {
+        let tcp =
+            libp2p_tcp::async_io::Transport::new(libp2p_tcp::Config::default().port_reuse(true))
+                .upgrade(upgrade::Version::V1Lazy)
+                .authenticate(
+                    libp2p_noise::NoiseAuthenticated::xx(&local_key)
+                        .expect("Signing libp2p-noise static DH keypair failed."),
+                )
+                .multiplex(libp2p_yamux::YamuxConfig::default());
+
+        let quic = {
+            let mut config = libp2p_quic::Config::new(&local_key);
+            config.support_draft_29 = true;
+            libp2p_quic::async_std::Transport::new(config)
+        };
+
+        let dns = DnsConfig::system(OrTransport::new(quic, tcp))
+            .await
+            .unwrap();
+
+        dns.map(|either_output, _| match either_output {
+            Either::Left((peer_id, muxer)) => (peer_id, StreamMuxerBox::new(muxer)),
+            Either::Right((peer_id, muxer)) => (peer_id, StreamMuxerBox::new(muxer)),
+        })
+        .boxed()
+    };
+
+    let mut swarm = SwarmBuilder::with_async_std_executor(
+        transport,
+        libp2p_perf::server::Behaviour::default(),
+        local_peer_id,
+    )
+    .substream_upgrade_protocol_override(upgrade::Version::V1Lazy)
+    .build();
+
+    swarm
+        .listen_on("/ip4/0.0.0.0/tcp/4001".parse().unwrap())
+        .unwrap();
+
+    swarm
+        .listen_on("/ip4/0.0.0.0/udp/4001/quic-v1".parse().unwrap())
+        .unwrap();
+
+    loop {
+        match swarm.next().await.unwrap() {
+            SwarmEvent::NewListenAddr { address, .. } => {
+                info!("Listening on {address}");
+            }
+            SwarmEvent::IncomingConnection { .. } => {}
+            e @ SwarmEvent::IncomingConnectionError { .. } => {
+                error!("{e:?}");
+            }
+            SwarmEvent::ConnectionEstablished {
+                peer_id, endpoint, ..
+            } => {
+                info!("Established connection to {:?} via {:?}", peer_id, endpoint);
+            }
+            SwarmEvent::ConnectionClosed { .. } => {}
+            SwarmEvent::Behaviour(libp2p_perf::server::Event {
+                remote_peer_id,
+                stats,
+            }) => {
+                let received_mebibytes = stats.params.received as f64 / 1024.0 / 1024.0;
+                let receive_time = (stats.timers.read_done - stats.timers.read_start).as_secs_f64();
+                let receive_bandwidth_mebibit_second = (received_mebibytes * 8.0) / receive_time;
+
+                let sent_mebibytes = stats.params.sent as f64 / 1024.0 / 1024.0;
+                let sent_time = (stats.timers.write_done - stats.timers.read_done).as_secs_f64();
+                let sent_bandwidth_mebibit_second = (sent_mebibytes * 8.0) / sent_time;
+
+                info!(
+                        "Finished run with {}: Received {:.2} MiB in {:.2} s with {:.2} MiBit/s and sent {:.2} MiB in {:.2} s with {:.2} MiBit/s",
+                        remote_peer_id,
+                        received_mebibytes,
+                        receive_time,
+                        receive_bandwidth_mebibit_second,
+                        sent_mebibytes,
+                        sent_time,
+                        sent_bandwidth_mebibit_second,
+                    )
+            }
+            e => panic!("{e:?}"),
+        }
+    }
+}

protocols/perf/src/client.rs

@@ -0,0 +1,62 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+mod behaviour;
+mod handler;
+
+use instant::Instant;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+pub use behaviour::{Behaviour, Event};
+
+/// Parameters for a single run, i.e. one stream, sending and receiving data.
+#[derive(Debug, Clone, Copy)]
+pub struct RunParams {
+    pub to_send: usize,
+    pub to_receive: usize,
+}
+
+/// Timers for a single run, i.e. one stream, sending and receiving data.
+#[derive(Debug, Clone, Copy)]
+pub struct RunTimers {
+    pub write_start: Instant,
+    pub write_done: Instant,
+    pub read_done: Instant,
+}
+
+/// Statistics for a single run, i.e. one stream, sending and receiving data.
+#[derive(Debug)]
+pub struct RunStats {
+    pub params: RunParams,
+    pub timers: RunTimers,
+}
+
+static NEXT_RUN_ID: AtomicUsize = AtomicUsize::new(1);
+
+/// Connection identifier.
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
+pub struct RunId(usize);
+
+impl RunId {
+    /// Returns the next available [`RunId`].
+    pub(crate) fn next() -> Self {
+        Self(NEXT_RUN_ID.fetch_add(1, Ordering::SeqCst))
+    }
+}

protocols/perf/src/client/behaviour.rs

@@ -0,0 +1,158 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+//! [`NetworkBehaviour`] of the libp2p perf client protocol.
+
+use std::{
+    collections::{HashSet, VecDeque},
+    task::{Context, Poll},
+};
+
+use libp2p_core::Multiaddr;
+use libp2p_identity::PeerId;
+use libp2p_swarm::{
+    derive_prelude::ConnectionEstablished, ConnectionClosed, ConnectionHandlerUpgrErr,
+    ConnectionId, FromSwarm, NetworkBehaviour, NetworkBehaviourAction, NotifyHandler,
+    PollParameters, THandlerInEvent, THandlerOutEvent,
+};
+use void::Void;
+
+use crate::client::handler::Handler;
+
+use super::{RunId, RunParams, RunStats};
+
+#[derive(Debug)]
+pub struct Event {
+    pub id: RunId,
+    pub result: Result<RunStats, ConnectionHandlerUpgrErr<Void>>,
+}
+
+#[derive(Default)]
+pub struct Behaviour {
+    /// Queue of actions to return when polled.
+    queued_events: VecDeque<NetworkBehaviourAction<Event, THandlerInEvent<Self>>>,
+    /// Set of connected peers.
+    connected: HashSet<PeerId>,
+}
+
+impl Behaviour {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn perf(&mut self, server: PeerId, params: RunParams) -> Result<RunId, PerfError> {
+        if !self.connected.contains(&server) {
+            return Err(PerfError::NotConnected);
+        }
+
+        let id = RunId::next();
+
+        self.queued_events
+            .push_back(NetworkBehaviourAction::NotifyHandler {
+                peer_id: server,
+                handler: NotifyHandler::Any,
+                event: crate::client::handler::Command { id, params },
+            });
+
+        Ok(id)
+    }
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum PerfError {
+    #[error("Not connected to peer")]
+    NotConnected,
+}
+
+impl NetworkBehaviour for Behaviour {
+    type ConnectionHandler = Handler;
+    type OutEvent = Event;
+
+    fn handle_established_outbound_connection(
+        &mut self,
+        _connection_id: ConnectionId,
+        _peer: PeerId,
+        _addr: &Multiaddr,
+        _role_override: libp2p_core::Endpoint,
+    ) -> Result<libp2p_swarm::THandler<Self>, libp2p_swarm::ConnectionDenied> {
+        Ok(Handler::default())
+    }
+
+    fn handle_established_inbound_connection(
+        &mut self,
+        _connection_id: ConnectionId,
+        _peer: PeerId,
+        _local_addr: &Multiaddr,
+        _remote_addr: &Multiaddr,
+    ) -> Result<libp2p_swarm::THandler<Self>, libp2p_swarm::ConnectionDenied> {
+        Ok(Handler::default())
+    }
+
+    fn on_swarm_event(&mut self, event: FromSwarm<Self::ConnectionHandler>) {
+        match event {
+            FromSwarm::ConnectionEstablished(ConnectionEstablished { peer_id, .. }) => {
+                self.connected.insert(peer_id);
+            }
+            FromSwarm::ConnectionClosed(ConnectionClosed {
+                peer_id,
+                connection_id: _,
+                endpoint: _,
+                handler: _,
+                remaining_established,
+            }) => {
+                if remaining_established == 0 {
+                    assert!(self.connected.remove(&peer_id));
+                }
+            }
+            FromSwarm::AddressChange(_)
+            | FromSwarm::DialFailure(_)
+            | FromSwarm::ListenFailure(_)
+            | FromSwarm::NewListener(_)
+            | FromSwarm::NewListenAddr(_)
+            | FromSwarm::ExpiredListenAddr(_)
+            | FromSwarm::ListenerError(_)
+            | FromSwarm::ListenerClosed(_)
+            | FromSwarm::NewExternalAddr(_)
+            | FromSwarm::ExpiredExternalAddr(_) => {}
+        }
+    }
+
+    fn on_connection_handler_event(
+        &mut self,
+        _event_source: PeerId,
+        _connection_id: ConnectionId,
+        super::handler::Event { id, result }: THandlerOutEvent<Self>,
+    ) {
+        self.queued_events
+            .push_back(NetworkBehaviourAction::GenerateEvent(Event { id, result }));
+    }
+
+    fn poll(
+        &mut self,
+        _cx: &mut Context<'_>,
+        _: &mut impl PollParameters,
+    ) -> Poll<NetworkBehaviourAction<Self::OutEvent, THandlerInEvent<Self>>> {
+        if let Some(event) = self.queued_events.pop_front() {
+            return Poll::Ready(event);
+        }
+
+        Poll::Pending
+    }
+}

protocols/perf/src/client/handler.rs

@@ -0,0 +1,196 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+use std::{
+    collections::VecDeque,
+    task::{Context, Poll},
+    time::{Duration, Instant},
+};
+
+use futures::{future::BoxFuture, stream::FuturesUnordered, FutureExt, StreamExt, TryFutureExt};
+use libp2p_core::upgrade::{DeniedUpgrade, ReadyUpgrade};
+use libp2p_swarm::{
+    handler::{
+        ConnectionEvent, DialUpgradeError, FullyNegotiatedInbound, FullyNegotiatedOutbound,
+        ListenUpgradeError,
+    },
+    ConnectionHandler, ConnectionHandlerEvent, ConnectionHandlerUpgrErr, KeepAlive,
+    SubstreamProtocol,
+};
+use void::Void;
+
+use super::{RunId, RunParams, RunStats};
+
+#[derive(Debug)]
+pub struct Command {
+    pub(crate) id: RunId,
+    pub(crate) params: RunParams,
+}
+
+#[derive(Debug)]
+pub struct Event {
+    pub(crate) id: RunId,
+    pub(crate) result: Result<RunStats, ConnectionHandlerUpgrErr<Void>>,
+}
+
+pub struct Handler {
+    /// Queue of events to return when polled.
+    queued_events: VecDeque<
+        ConnectionHandlerEvent<
+            <Self as ConnectionHandler>::OutboundProtocol,
+            <Self as ConnectionHandler>::OutboundOpenInfo,
+            <Self as ConnectionHandler>::OutEvent,
+            <Self as ConnectionHandler>::Error,
+        >,
+    >,
+
+    outbound: FuturesUnordered<BoxFuture<'static, Result<Event, std::io::Error>>>,
+
+    keep_alive: KeepAlive,
+}
+
+impl Handler {
+    pub fn new() -> Self {
+        Self {
+            queued_events: Default::default(),
+            outbound: Default::default(),
+            keep_alive: KeepAlive::Yes,
+        }
+    }
+}
+
+impl Default for Handler {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl ConnectionHandler for Handler {
+    type InEvent = Command;
+    type OutEvent = Event;
+    type Error = Void;
+    type InboundProtocol = DeniedUpgrade;
+    type OutboundProtocol = ReadyUpgrade<&'static [u8]>;
+    type OutboundOpenInfo = Command;
+    type InboundOpenInfo = ();
+
+    fn listen_protocol(&self) -> SubstreamProtocol<Self::InboundProtocol, Self::InboundOpenInfo> {
+        SubstreamProtocol::new(DeniedUpgrade, ())
+    }
+
+    fn on_behaviour_event(&mut self, command: Self::InEvent) {
+        self.queued_events
+            .push_back(ConnectionHandlerEvent::OutboundSubstreamRequest {
+                protocol: SubstreamProtocol::new(ReadyUpgrade::new(crate::PROTOCOL_NAME), command),
+            })
+    }
+
+    fn on_connection_event(
+        &mut self,
+        event: ConnectionEvent<
+            Self::InboundProtocol,
+            Self::OutboundProtocol,
+            Self::InboundOpenInfo,
+            Self::OutboundOpenInfo,
+        >,
+    ) {
+        match event {
+            ConnectionEvent::FullyNegotiatedInbound(FullyNegotiatedInbound {
+                protocol, ..
+            }) => void::unreachable(protocol),
+            ConnectionEvent::FullyNegotiatedOutbound(FullyNegotiatedOutbound {
+                protocol,
+                info: Command { params, id },
+            }) => self.outbound.push(
+                crate::protocol::send_receive(params, protocol)
+                    .map_ok(move |timers| Event {
+                        id,
+                        result: Ok(RunStats { params, timers }),
+                    })
+                    .boxed(),
+            ),
+
+            ConnectionEvent::AddressChange(_) => {}
+            ConnectionEvent::DialUpgradeError(DialUpgradeError {
+                info: Command { id, .. },
+                error,
+            }) => self
+                .queued_events
+                .push_back(ConnectionHandlerEvent::Custom(Event {
+                    id,
+                    result: Err(error),
+                })),
+            ConnectionEvent::ListenUpgradeError(ListenUpgradeError { info: (), error }) => {
+                match error {
+                    ConnectionHandlerUpgrErr::Timeout => {}
+                    ConnectionHandlerUpgrErr::Timer => {}
+                    ConnectionHandlerUpgrErr::Upgrade(error) => match error {
+                        libp2p_core::UpgradeError::Select(_) => {}
+                        libp2p_core::UpgradeError::Apply(v) => void::unreachable(v),
+                    },
+                }
+            }
+        }
+    }
+
+    fn connection_keep_alive(&self) -> KeepAlive {
+        self.keep_alive
+    }
+
+    fn poll(
+        &mut self,
+        cx: &mut Context<'_>,
+    ) -> Poll<
+        ConnectionHandlerEvent<
+            Self::OutboundProtocol,
+            Self::OutboundOpenInfo,
+            Self::OutEvent,
+            Self::Error,
+        >,
+    > {
+        // Return queued events.
+        if let Some(event) = self.queued_events.pop_front() {
+            return Poll::Ready(event);
+        }
+
+        while let Poll::Ready(Some(result)) = self.outbound.poll_next_unpin(cx) {
+            match result {
+                Ok(event) => return Poll::Ready(ConnectionHandlerEvent::Custom(event)),
+                Err(e) => {
+                    panic!("{e:?}")
+                }
+            }
+        }
+
+        if self.outbound.is_empty() {
+            match self.keep_alive {
+                KeepAlive::Yes => {
+                    self.keep_alive = KeepAlive::Until(Instant::now() + Duration::from_secs(10));
+                }
+                KeepAlive::Until(_) => {}
+                KeepAlive::No => panic!("Handler never sets KeepAlive::No."),
+            }
+        } else {
+            self.keep_alive = KeepAlive::Yes
+        }
+
+        Poll::Pending
+    }
+}

protocols/perf/src/lib.rs

@@ -0,0 +1,31 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+//! Implementation of the [libp2p perf protocol](https://github.com/libp2p/specs/pull/478/).
+//!
+//! Do not use in untrusted environments.
+
+#![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
+
+pub mod client;
+mod protocol;
+pub mod server;
+
+pub const PROTOCOL_NAME: &[u8; 11] = b"/perf/1.0.0";

protocols/perf/src/protocol.rs

@@ -0,0 +1,206 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+use instant::Instant;
+
+use futures::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
+
+use crate::{client, server};
+
+const BUF: [u8; 1024] = [0; 1024];
+
+pub async fn send_receive<S: AsyncRead + AsyncWrite + Unpin>(
+    params: client::RunParams,
+    mut stream: S,
+) -> Result<client::RunTimers, std::io::Error> {
+    let client::RunParams {
+        to_send,
+        to_receive,
+    } = params;
+
+    let mut receive_buf = vec![0; 1024];
+
+    stream.write_all(&(to_receive as u64).to_be_bytes()).await?;
+
+    let write_start = Instant::now();
+
+    let mut sent = 0;
+    while sent < to_send {
+        let n = std::cmp::min(to_send - sent, BUF.len());
+        let buf = &BUF[..n];
+
+        sent += stream.write(buf).await?;
+    }
+
+    stream.close().await?;
+
+    let write_done = Instant::now();
+
+    let mut received = 0;
+    while received < to_receive {
+        received += stream.read(&mut receive_buf).await?;
+    }
+
+    let read_done = Instant::now();
+
+    Ok(client::RunTimers {
+        write_start,
+        write_done,
+        read_done,
+    })
+}
+
+pub async fn receive_send<S: AsyncRead + AsyncWrite + Unpin>(
+    mut stream: S,
+) -> Result<server::RunStats, std::io::Error> {
+    let to_send = {
+        let mut buf = [0; 8];
+        stream.read_exact(&mut buf).await?;
+
+        u64::from_be_bytes(buf) as usize
+    };
+
+    let read_start = Instant::now();
+
+    let mut receive_buf = vec![0; 1024];
+    let mut received = 0;
+    loop {
+        let n = stream.read(&mut receive_buf).await?;
+        received += n;
+        if n == 0 {
+            break;
+        }
+    }
+
+    let read_done = Instant::now();
+
+    let mut sent = 0;
+    while sent < to_send {
+        let n = std::cmp::min(to_send - sent, BUF.len());
+        let buf = &BUF[..n];
+
+        sent += stream.write(buf).await?;
+    }
+
+    stream.close().await?;
+    let write_done = Instant::now();
+
+    Ok(server::RunStats {
+        params: server::RunParams { sent, received },
+        timers: server::RunTimers {
+            read_start,
+            read_done,
+            write_done,
+        },
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use futures::{executor::block_on, AsyncRead, AsyncWrite};
+    use std::{
+        pin::Pin,
+        sync::{Arc, Mutex},
+        task::Poll,
+    };
+
+    #[derive(Clone)]
+    struct DummyStream {
+        inner: Arc<Mutex<DummyStreamInner>>,
+    }
+
+    struct DummyStreamInner {
+        read: Vec<u8>,
+        write: Vec<u8>,
+    }
+
+    impl DummyStream {
+        fn new(read: Vec<u8>) -> Self {
+            Self {
+                inner: Arc::new(Mutex::new(DummyStreamInner {
+                    read,
+                    write: Vec::new(),
+                })),
+            }
+        }
+    }
+
+    impl Unpin for DummyStream {}
+
+    impl AsyncWrite for DummyStream {
+        fn poll_write(
+            self: std::pin::Pin<&mut Self>,
+            cx: &mut std::task::Context<'_>,
+            buf: &[u8],
+        ) -> std::task::Poll<std::io::Result<usize>> {
+            Pin::new(&mut self.inner.lock().unwrap().write).poll_write(cx, buf)
+        }
+
+        fn poll_flush(
+            self: std::pin::Pin<&mut Self>,
+            cx: &mut std::task::Context<'_>,
+        ) -> std::task::Poll<std::io::Result<()>> {
+            Pin::new(&mut self.inner.lock().unwrap().write).poll_flush(cx)
+        }
+
+        fn poll_close(
+            self: std::pin::Pin<&mut Self>,
+            cx: &mut std::task::Context<'_>,
+        ) -> std::task::Poll<std::io::Result<()>> {
+            Pin::new(&mut self.inner.lock().unwrap().write).poll_close(cx)
+        }
+    }
+
+    impl AsyncRead for DummyStream {
+        fn poll_read(
+            self: Pin<&mut Self>,
+            _cx: &mut std::task::Context<'_>,
+            buf: &mut [u8],
+        ) -> std::task::Poll<std::io::Result<usize>> {
+            let amt = std::cmp::min(buf.len(), self.inner.lock().unwrap().read.len());
+            let new = self.inner.lock().unwrap().read.split_off(amt);
+
+            buf[..amt].copy_from_slice(self.inner.lock().unwrap().read.as_slice());
+
+            self.inner.lock().unwrap().read = new;
+            Poll::Ready(Ok(amt))
+        }
+    }
+
+    #[test]
+    fn test_client() {
+        let stream = DummyStream::new(vec![0]);
+
+        block_on(send_receive(
+            client::RunParams {
+                to_send: 0,
+                to_receive: 0,
+            },
+            stream.clone(),
+        ))
+        .unwrap();
+
+        assert_eq!(
+            stream.inner.lock().unwrap().write,
+            0u64.to_be_bytes().to_vec()
+        );
+    }
+}

protocols/perf/src/server.rs

@@ -0,0 +1,48 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+mod behaviour;
+mod handler;
+
+use instant::Instant;
+
+pub use behaviour::{Behaviour, Event};
+
+/// Parameters for a single run, i.e. one stream, sending and receiving data.
+#[derive(Debug, Clone, Copy)]
+pub struct RunParams {
+    pub sent: usize,
+    pub received: usize,
+}
+
+/// Timers for a single run, i.e. one stream, sending and receiving data.
+#[derive(Debug, Clone, Copy)]
+pub struct RunTimers {
+    pub read_start: Instant,
+    pub read_done: Instant,
+    pub write_done: Instant,
+}
+
+/// Statistics for a single run, i.e. one stream, sending and receiving data.
+#[derive(Debug)]
+pub struct RunStats {
+    pub params: RunParams,
+    pub timers: RunTimers,
+}

protocols/perf/src/server/behaviour.rs

@@ -0,0 +1,121 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+//! [`NetworkBehaviour`] of the libp2p perf server protocol.
+
+use std::{
+    collections::VecDeque,
+    task::{Context, Poll},
+};
+
+use libp2p_identity::PeerId;
+use libp2p_swarm::{
+    ConnectionId, FromSwarm, NetworkBehaviour, NetworkBehaviourAction, PollParameters,
+    THandlerInEvent, THandlerOutEvent,
+};
+
+use crate::server::handler::Handler;
+
+use super::RunStats;
+
+#[derive(Debug)]
+pub struct Event {
+    pub remote_peer_id: PeerId,
+    pub stats: RunStats,
+}
+
+#[derive(Default)]
+pub struct Behaviour {
+    /// Queue of actions to return when polled.
+    queued_events: VecDeque<NetworkBehaviourAction<Event, THandlerInEvent<Self>>>,
+}
+
+impl Behaviour {
+    pub fn new() -> Self {
+        Self::default()
+    }
+}
+
+impl NetworkBehaviour for Behaviour {
+    type ConnectionHandler = Handler;
+    type OutEvent = Event;
+
+    fn handle_established_inbound_connection(
+        &mut self,
+        _connection_id: ConnectionId,
+        _peer: PeerId,
+        _local_addr: &libp2p_core::Multiaddr,
+        _remote_addr: &libp2p_core::Multiaddr,
+    ) -> Result<libp2p_swarm::THandler<Self>, libp2p_swarm::ConnectionDenied> {
+        Ok(Handler::default())
+    }
+
+    fn handle_established_outbound_connection(
+        &mut self,
+        _connection_id: ConnectionId,
+        _peer: PeerId,
+        _addr: &libp2p_core::Multiaddr,
+        _role_override: libp2p_core::Endpoint,
+    ) -> Result<libp2p_swarm::THandler<Self>, libp2p_swarm::ConnectionDenied> {
+        Ok(Handler::default())
+    }
+
+    fn on_swarm_event(&mut self, event: FromSwarm<Self::ConnectionHandler>) {
+        match event {
+            FromSwarm::ConnectionEstablished(_) => {}
+            FromSwarm::ConnectionClosed(_) => {}
+            FromSwarm::AddressChange(_) => {}
+            FromSwarm::DialFailure(_) => {}
+            FromSwarm::ListenFailure(_) => {}
+            FromSwarm::NewListener(_) => {}
+            FromSwarm::NewListenAddr(_) => {}
+            FromSwarm::ExpiredListenAddr(_) => {}
+            FromSwarm::ListenerError(_) => {}
+            FromSwarm::ListenerClosed(_) => {}
+            FromSwarm::NewExternalAddr(_) => {}
+            FromSwarm::ExpiredExternalAddr(_) => {}
+        }
+    }
+
+    fn on_connection_handler_event(
+        &mut self,
+        event_source: PeerId,
+        _connection_id: ConnectionId,
+        super::handler::Event { stats }: THandlerOutEvent<Self>,
+    ) {
+        self.queued_events
+            .push_back(NetworkBehaviourAction::GenerateEvent(Event {
+                remote_peer_id: event_source,
+                stats,
+            }))
+    }
+
+    fn poll(
+        &mut self,
+        _cx: &mut Context<'_>,
+        _: &mut impl PollParameters,
+    ) -> Poll<NetworkBehaviourAction<Self::OutEvent, THandlerInEvent<Self>>> {
+        if let Some(event) = self.queued_events.pop_front() {
+            return Poll::Ready(event);
+        }
+
+        Poll::Pending
+    }
+}

protocols/perf/src/server/handler.rs

@@ -0,0 +1,159 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+use std::{
+    task::{Context, Poll},
+    time::{Duration, Instant},
+};
+
+use futures::{future::BoxFuture, stream::FuturesUnordered, FutureExt, StreamExt};
+use libp2p_core::upgrade::{DeniedUpgrade, ReadyUpgrade};
+use libp2p_swarm::{
+    handler::{
+        ConnectionEvent, DialUpgradeError, FullyNegotiatedInbound, FullyNegotiatedOutbound,
+        ListenUpgradeError,
+    },
+    ConnectionHandler, ConnectionHandlerEvent, ConnectionHandlerUpgrErr, KeepAlive,
+    SubstreamProtocol,
+};
+use log::error;
+use void::Void;
+
+use super::RunStats;
+
+#[derive(Debug)]
+pub struct Event {
+    pub stats: RunStats,
+}
+
+pub struct Handler {
+    inbound: FuturesUnordered<BoxFuture<'static, Result<RunStats, std::io::Error>>>,
+    keep_alive: KeepAlive,
+}
+
+impl Handler {
+    pub fn new() -> Self {
+        Self {
+            inbound: Default::default(),
+            keep_alive: KeepAlive::Yes,
+        }
+    }
+}
+
+impl Default for Handler {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl ConnectionHandler for Handler {
+    type InEvent = Void;
+    type OutEvent = Event;
+    type Error = Void;
+    type InboundProtocol = ReadyUpgrade<&'static [u8]>;
+    type OutboundProtocol = DeniedUpgrade;
+    type OutboundOpenInfo = Void;
+    type InboundOpenInfo = ();
+
+    fn listen_protocol(&self) -> SubstreamProtocol<Self::InboundProtocol, Self::InboundOpenInfo> {
+        SubstreamProtocol::new(ReadyUpgrade::new(crate::PROTOCOL_NAME), ())
+    }
+
+    fn on_behaviour_event(&mut self, v: Self::InEvent) {
+        void::unreachable(v)
+    }
+
+    fn on_connection_event(
+        &mut self,
+        event: ConnectionEvent<
+            Self::InboundProtocol,
+            Self::OutboundProtocol,
+            Self::InboundOpenInfo,
+            Self::OutboundOpenInfo,
+        >,
+    ) {
+        match event {
+            ConnectionEvent::FullyNegotiatedInbound(FullyNegotiatedInbound {
+                protocol,
+                info: _,
+            }) => {
+                self.inbound
+                    .push(crate::protocol::receive_send(protocol).boxed());
+            }
+            ConnectionEvent::FullyNegotiatedOutbound(FullyNegotiatedOutbound { info, .. }) => {
+                void::unreachable(info)
+            }
+
+            ConnectionEvent::DialUpgradeError(DialUpgradeError { info, .. }) => {
+                void::unreachable(info)
+            }
+            ConnectionEvent::AddressChange(_) => {}
+            ConnectionEvent::ListenUpgradeError(ListenUpgradeError { info: (), error }) => {
+                match error {
+                    ConnectionHandlerUpgrErr::Timeout => {}
+                    ConnectionHandlerUpgrErr::Timer => {}
+                    ConnectionHandlerUpgrErr::Upgrade(error) => match error {
+                        libp2p_core::UpgradeError::Select(_) => {}
+                        libp2p_core::UpgradeError::Apply(v) => void::unreachable(v),
+                    },
+                }
+            }
+        }
+    }
+
+    fn connection_keep_alive(&self) -> KeepAlive {
+        self.keep_alive
+    }
+
+    fn poll(
+        &mut self,
+        cx: &mut Context<'_>,
+    ) -> Poll<
+        ConnectionHandlerEvent<
+            Self::OutboundProtocol,
+            Self::OutboundOpenInfo,
+            Self::OutEvent,
+            Self::Error,
+        >,
+    > {
+        while let Poll::Ready(Some(result)) = self.inbound.poll_next_unpin(cx) {
+            match result {
+                Ok(stats) => return Poll::Ready(ConnectionHandlerEvent::Custom(Event { stats })),
+                Err(e) => {
+                    error!("{e:?}")
+                }
+            }
+        }
+
+        if self.inbound.is_empty() {
+            match self.keep_alive {
+                KeepAlive::Yes => {
+                    self.keep_alive = KeepAlive::Until(Instant::now() + Duration::from_secs(10));
+                }
+                KeepAlive::Until(_) => {}
+                KeepAlive::No => panic!("Handler never sets KeepAlive::No."),
+            }
+        } else {
+            self.keep_alive = KeepAlive::Yes
+        }
+
+        Poll::Pending
+    }
+}

protocols/perf/tests/lib.rs

@@ -0,0 +1,62 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+use libp2p_perf::{
+    client::{self, RunParams},
+    server,
+};
+use libp2p_swarm::{Swarm, SwarmEvent};
+use libp2p_swarm_test::SwarmExt;
+
+#[async_std::test]
+async fn perf() {
+    let _ = env_logger::try_init();
+
+    let mut server = Swarm::new_ephemeral(|_| server::Behaviour::new());
+    let server_peer_id = *server.local_peer_id();
+    let mut client = Swarm::new_ephemeral(|_| client::Behaviour::new());
+
+    server.listen().await;
+    client.connect(&mut server).await;
+
+    async_std::task::spawn(server.loop_on_next());
+
+    client
+        .behaviour_mut()
+        .perf(
+            server_peer_id,
+            RunParams {
+                to_send: 0,
+                to_receive: 0,
+            },
+        )
+        .unwrap();
+
+    client
+        .wait(|e| match e {
+            SwarmEvent::IncomingConnection { .. } => panic!(),
+            SwarmEvent::ConnectionEstablished { .. } => None,
+            SwarmEvent::Dialing(_) => None,
+            SwarmEvent::Behaviour(client::Event { result, .. }) => Some(result),
+            e => panic!("{e:?}"),
+        })
+        .await
+        .unwrap();
+}