feat(autonat): Implement AutoNATv2

Closes: libp2p#4524

This is the implementation of the evolved AutoNAT protocol, named AutonatV2 as defined in the [spec](https://github.com/libp2p/specs/blob/03718ef0f2dea4a756a85ba716ee33f97e4a6d6c/autonat/autonat-v2.md).
The stabilization PR for the spec can be found under libp2p/specs#538.

The work on the Rust implementation can be found in the PR to my fork: #1.

The implementation has been smoke-tested with the Go implementation (PR: libp2p/go-libp2p#2469).

The new protocol addresses shortcomings of the original AutoNAT protocol:

- Since the server now always dials back over a newly allocated port, this made libp2p#4568 necessary; the client can be sure of the reachability state for other peers, even if the connection to the server was made through a hole punch.
- The server can now test addresses different from the observed address (i.e., the connection to the server was made through a `p2p-circuit`). To mitigate against DDoS attacks, the client has to send more data to the server than the dial-back costs.

Pull-Request: libp2p#5526.

Cargo.toml

@@ -2,6 +2,7 @@
 members = [
     "core",
     "examples/autonat",
+    "examples/autonatv2",
     "examples/browser-webrtc",
     "examples/chat",
     "examples/dcutr",

examples/autonatv2/Cargo.toml

@@ -0,0 +1,38 @@
+[package]
+name = "autonatv2"
+version = "0.1.0"
+edition = "2021"
+publish = false
+license = "MIT or Apache-2.0"
+
+[package.metadata.release]
+release = false
+
+[[bin]]
+name = "autonatv2_client"
+
+[[bin]]
+name = "autonatv2_server"
+
+[dependencies]
+libp2p = { workspace = true, features = ["macros", "tokio", "tcp", "noise", "yamux", "autonat", "identify", "dns", "quic"] }
+clap = { version = "4.4.18", features = ["derive"] }
+tokio = { version = "1.35.1", features = ["macros", "rt-multi-thread"] }
+tracing = "0.1.40"
+tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
+rand = "0.8.5"
+opentelemetry = { version = "0.21.0", optional = true }
+opentelemetry_sdk = { version = "0.21.1", optional = true, features = ["rt-tokio"] }
+tracing-opentelemetry = { version = "0.22.0", optional = true }
+opentelemetry-jaeger = { version = "0.20.0", optional = true, features = ["rt-tokio"] }
+cfg-if = "1.0.0"
+
+[features]
+jaeger = ["opentelemetry", "opentelemetry_sdk", "tracing-opentelemetry", "opentelemetry-jaeger"]
+opentelemetry = ["dep:opentelemetry"]
+opentelemetry_sdk = ["dep:opentelemetry_sdk"]
+tracing-opentelemetry = ["dep:tracing-opentelemetry"]
+opentelemetry-jaeger = ["dep:opentelemetry-jaeger"]
+
+[lints]
+workspace = true

examples/autonatv2/Dockerfile

@@ -0,0 +1,20 @@
+FROM rust:1.75-alpine as builder
+
+RUN apk add musl-dev
+
+WORKDIR /workspace
+COPY . .
+RUN --mount=type=cache,target=./target \
+    --mount=type=cache,target=/usr/local/cargo/registry \
+    cargo build --release --package autonatv2 --bin autonatv2_server -F jaeger
+
+RUN --mount=type=cache,target=./target \
+    mv ./target/release/autonatv2_server /usr/local/bin/autonatv2_server
+
+FROM alpine:latest
+
+COPY --from=builder /usr/local/bin/autonatv2_server /app/autonatv2_server
+
+EXPOSE 4884
+
+ENTRYPOINT [ "/app/autonatv2_server", "-l", "4884" ]

examples/autonatv2/docker-compose.yml

@@ -0,0 +1,16 @@
+version: '3'
+
+services:
+    autonatv2:
+        build:
+            context: ../..
+            dockerfile: examples/autonatv2/Dockerfile
+        ports:
+            - 4884:4884
+    jaeger:
+        image: jaegertracing/all-in-one
+        ports:
+            - 6831:6831/udp
+            - 6832:6832/udp
+            - 16686:16686
+            - 14268:14268

examples/autonatv2/src/bin/autonatv2_client.rs

@@ -0,0 +1,111 @@
+use std::{error::Error, net::Ipv4Addr, time::Duration};
+
+use clap::Parser;
+use libp2p::{
+    autonat,
+    futures::StreamExt,
+    identify, identity,
+    multiaddr::Protocol,
+    noise,
+    swarm::{dial_opts::DialOpts, NetworkBehaviour, SwarmEvent},
+    tcp, yamux, Multiaddr, SwarmBuilder,
+};
+use rand::rngs::OsRng;
+use tracing_subscriber::EnvFilter;
+
+#[derive(Debug, Parser)]
+#[clap(name = "libp2p autonatv2 client")]
+struct Opt {
+    /// Port where the client will listen for incoming connections.
+    #[clap(short = 'p', long, default_value_t = 0)]
+    listen_port: u16,
+
+    /// Address of the server where want to connect to.
+    #[clap(short = 'a', long)]
+    server_address: Multiaddr,
+
+    /// Probe interval in seconds.
+    #[clap(short = 't', long, default_value = "2")]
+    probe_interval: u64,
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error>> {
+    let _ = tracing_subscriber::fmt()
+        .with_env_filter(EnvFilter::from_default_env())
+        .try_init();
+
+    let opt = Opt::parse();
+
+    let mut swarm = SwarmBuilder::with_new_identity()
+        .with_tokio()
+        .with_tcp(
+            tcp::Config::default(),
+            noise::Config::new,
+            yamux::Config::default,
+        )?
+        .with_quic()
+        .with_dns()?
+        .with_behaviour(|key| Behaviour::new(key.public(), opt.probe_interval))?
+        .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(10)))
+        .build();
+
+    swarm.listen_on(
+        Multiaddr::empty()
+            .with(Protocol::Ip4(Ipv4Addr::UNSPECIFIED))
+            .with(Protocol::Tcp(opt.listen_port)),
+    )?;
+
+    swarm.dial(
+        DialOpts::unknown_peer_id()
+            .address(opt.server_address)
+            .build(),
+    )?;
+
+    loop {
+        match swarm.select_next_some().await {
+            SwarmEvent::NewListenAddr { address, .. } => {
+                println!("Listening on {address:?}");
+            }
+            SwarmEvent::Behaviour(BehaviourEvent::Autonat(autonat::v2::client::Event {
+                server,
+                tested_addr,
+                bytes_sent,
+                result: Ok(()),
+            })) => {
+                println!("Tested {tested_addr} with {server}. Sent {bytes_sent} bytes for verification. Everything Ok and verified.");
+            }
+            SwarmEvent::Behaviour(BehaviourEvent::Autonat(autonat::v2::client::Event {
+                server,
+                tested_addr,
+                bytes_sent,
+                result: Err(e),
+            })) => {
+                println!("Tested {tested_addr} with {server}. Sent {bytes_sent} bytes for verification. Failed with {e:?}.");
+            }
+            SwarmEvent::ExternalAddrConfirmed { address } => {
+                println!("External address confirmed: {address}");
+            }
+            _ => {}
+        }
+    }
+}
+
+#[derive(NetworkBehaviour)]
+pub struct Behaviour {
+    autonat: autonat::v2::client::Behaviour,
+    identify: identify::Behaviour,
+}
+
+impl Behaviour {
+    pub fn new(key: identity::PublicKey, probe_interval: u64) -> Self {
+        Self {
+            autonat: autonat::v2::client::Behaviour::new(
+                OsRng,
+                autonat::v2::client::Config::default()
+                    .with_probe_interval(Duration::from_secs(probe_interval)),
+            ),
+            identify: identify::Behaviour::new(identify::Config::new("/ipfs/0.1.0".into(), key)),
+        }
+    }
+}

examples/autonatv2/src/bin/autonatv2_server.rs

@@ -0,0 +1,87 @@
+use std::{error::Error, net::Ipv4Addr, time::Duration};
+
+use cfg_if::cfg_if;
+use clap::Parser;
+use libp2p::{
+    autonat,
+    futures::StreamExt,
+    identify, identity,
+    multiaddr::Protocol,
+    noise,
+    swarm::{NetworkBehaviour, SwarmEvent},
+    tcp, yamux, Multiaddr, SwarmBuilder,
+};
+use rand::rngs::OsRng;
+
+#[derive(Debug, Parser)]
+#[clap(name = "libp2p autonatv2 server")]
+struct Opt {
+    #[clap(short, long, default_value_t = 0)]
+    listen_port: u16,
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error>> {
+    cfg_if! {
+        if #[cfg(feature = "jaeger")] {
+            use tracing_subscriber::layer::SubscriberExt;
+            use opentelemetry_sdk::runtime::Tokio;
+            let tracer = opentelemetry_jaeger::new_agent_pipeline()
+                .with_endpoint("jaeger:6831")
+                .with_service_name("autonatv2")
+                .install_batch(Tokio)?;
+            let telemetry = tracing_opentelemetry::layer().with_tracer(tracer);
+            let subscriber = tracing_subscriber::Registry::default()
+                .with(telemetry);
+        } else {
+            let subscriber = tracing_subscriber::fmt()
+                .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
+                .finish();
+        }
+    }
+    tracing::subscriber::set_global_default(subscriber).expect("setting default subscriber failed");
+
+    let opt = Opt::parse();
+
+    let mut swarm = SwarmBuilder::with_new_identity()
+        .with_tokio()
+        .with_tcp(
+            tcp::Config::default(),
+            noise::Config::new,
+            yamux::Config::default,
+        )?
+        .with_quic()
+        .with_dns()?
+        .with_behaviour(|key| Behaviour::new(key.public()))?
+        .with_swarm_config(|c| c.with_idle_connection_timeout(Duration::from_secs(60)))
+        .build();
+
+    swarm.listen_on(
+        Multiaddr::empty()
+            .with(Protocol::Ip4(Ipv4Addr::UNSPECIFIED))
+            .with(Protocol::Tcp(opt.listen_port)),
+    )?;
+
+    loop {
+        match swarm.select_next_some().await {
+            SwarmEvent::NewListenAddr { address, .. } => println!("Listening on {address:?}"),
+            SwarmEvent::Behaviour(event) => println!("{event:?}"),
+            e => println!("{e:?}"),
+        }
+    }
+}
+
+#[derive(NetworkBehaviour)]
+pub struct Behaviour {
+    autonat: autonat::v2::server::Behaviour,
+    identify: identify::Behaviour,
+}
+
+impl Behaviour {
+    pub fn new(key: identity::PublicKey) -> Self {
+        Self {
+            autonat: autonat::v2::server::Behaviour::new(OsRng),
+            identify: identify::Behaviour::new(identify::Config::new("/ipfs/0.1.0".into(), key)),
+        }
+    }
+}

protocols/autonat/CHANGELOG.md

@@ -3,6 +3,13 @@
 - Due to the refactor of `Transport` it's no longer required to create a seperate transport for
 AutoNAT where port reuse is disabled. This information is now passed by the behaviour.
   See [PR 4568](https://github.com/libp2p/rust-libp2p/pull/4568).
+- Introduce the new AutoNATv2 protocol.
+  It's split into a client and a server part, represented in their respective modules
+  Features:
+    - The server now always dials back over a newly allocated port.
+      This more accurately reflects the reachability state for other peers and avoids accidental hole punching.
+    - The server can now test addresses different from the observed address (i.e., the connection to the server was made through a `p2p-circuit`). To mitigate against DDoS attacks, the client has to send more data to the server than the dial-back costs.
+  See [PR 5526](https://github.com/libp2p/rust-libp2p/pull/5526).
 
 <!-- Update to libp2p-swarm v0.45.0 -->
 

protocols/autonat/Cargo.toml

@@ -3,32 +3,47 @@ name = "libp2p-autonat"
 edition = "2021"
 rust-version = { workspace = true }
 description = "NAT and firewall detection for libp2p"
-authors = ["David Craven <[email protected]>", "Elena Frank <[email protected]>"]
 version = "0.13.0"
+authors = ["David Craven <[email protected]>", "Elena Frank <[email protected]>", "Hannes Furmans <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"
 keywords = ["peer-to-peer", "libp2p", "networking"]
 categories = ["network-programming", "asynchronous"]
 
+
 [dependencies]
-async-trait = "0.1"
+async-trait = { version = "0.1", optional = true }
+asynchronous-codec = { workspace = true }
+bytes = { version = "1", optional = true }
+either = { version = "1.9.0", optional = true }
 futures = { workspace = true }
+futures-bounded = { workspace = true, optional = true }
 futures-timer = "3.0"
-web-time = { workspace = true }
+web-time = { workspace = true, optional = true }
 libp2p-core = { workspace = true }
-libp2p-swarm = { workspace = true }
-libp2p-request-response = { workspace = true }
 libp2p-identity = { workspace = true }
+libp2p-request-response = { workspace = true, optional = true }
+libp2p-swarm = { workspace = true }
 quick-protobuf = "0.8"
-rand = "0.8"
 tracing = { workspace = true }
 quick-protobuf-codec = { workspace = true }
-asynchronous-codec = { workspace = true }
+rand = "0.8"
+rand_core = { version = "0.6", optional = true }
+thiserror = { version = "1.0.52", optional = true }
+void = { version = "1", optional = true }
 
 [dev-dependencies]
+tokio = { version = "1", features = ["macros", "rt", "sync"]}
 async-std = { version = "1.10", features = ["attributes"] }
 libp2p-swarm-test = { path = "../../swarm-test" }
-tracing-subscriber = { workspace = true, features = ["env-filter"] }
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+libp2p-identify = { workspace = true }
+libp2p-swarm = { workspace = true, features = ["macros"]}
+
+[features]
+default = ["v1", "v2"]
+v1 = ["dep:libp2p-request-response", "dep:web-time", "dep:async-trait"]
+v2 = ["dep:bytes", "dep:either", "dep:futures-bounded", "dep:thiserror", "dep:void", "dep:rand_core"]
 
 # Passing arguments to the docsrs builder in order to properly document cfg's.
 # More information: https://docs.rs/about/builds#cross-compiling