feat(quic): allow disabling of path MTU discovery

Path MTU discovery seems to be broken in QUIC right now on Windows and we had to disable it in Subspace.

Related: autonomys/subspace#2195.

Pull-Request: #4823.

Co-authored-by: Shamil Gadelshin <shamilgadelshin@gmail.com>

Author: nazar-pc

Cargo.lock

@@ -93,7 +93,7 @@ libp2p-perf = { version = "0.3.0", path = "protocols/perf" }
 libp2p-ping = { version = "0.44.0", path = "protocols/ping" }
 libp2p-plaintext = { version = "0.41.0", path = "transports/plaintext" }
 libp2p-pnet = { version = "0.24.0", path = "transports/pnet" }
-libp2p-quic = { version = "0.10.0", path = "transports/quic" }
+libp2p-quic = { version = "0.10.1", path = "transports/quic" }
 libp2p-relay = { version = "0.17.0", path = "protocols/relay" }
 libp2p-rendezvous = { version = "0.14.0", path = "protocols/rendezvous" }
 libp2p-request-response = { version = "0.26.0", path = "protocols/request-response" }

Cargo.toml

@@ -1,3 +1,8 @@
+## 0.10.1 - unreleased
+
+- Allow disabling path MTU discovery.
+  See [PR 4823](https://github.com/libp2p/rust-libp2p/pull/4823).
+
 ## 0.10.0
 
 - Improve hole-punch timing.

transports/quic/CHANGELOG.md

@@ -1,6 +1,6 @@
 [package]
 name = "libp2p-quic"
-version = "0.10.0"
+version = "0.10.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2021"
 rust-version = { workspace = true }

transports/quic/Cargo.toml

@@ -18,7 +18,7 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-use quinn::VarInt;
+use quinn::{MtuDiscoveryConfig, VarInt};
 use std::{sync::Arc, time::Duration};
 
 /// Config for the transport.
@@ -63,6 +63,9 @@ pub struct Config {
     server_tls_config: Arc<rustls::ServerConfig>,
     /// Libp2p identity of the node.
     keypair: libp2p_identity::Keypair,
+
+    /// Parameters governing MTU discovery. See [`MtuDiscoveryConfig`] for details.
+    mtu_discovery_config: Option<MtuDiscoveryConfig>,
 }
 
 impl Config {
@@ -83,8 +86,15 @@ impl Config {
             // Ensure that one stream is not consuming the whole connection.
             max_stream_data: 10_000_000,
             keypair: keypair.clone(),
+            mtu_discovery_config: Some(Default::default()),
         }
     }
+
+    /// Disable MTU path discovery (it is enabled by default).
+    pub fn disable_path_mtu_discovery(mut self) -> Self {
+        self.mtu_discovery_config = None;
+        self
+    }
 }
 
 /// Represents the inner configuration for [`quinn`].
@@ -108,6 +118,7 @@ impl From<Config> for QuinnConfig {
             support_draft_29,
             handshake_timeout: _,
             keypair,
+            mtu_discovery_config,
         } = config;
         let mut transport = quinn::TransportConfig::default();
         // Disable uni-directional streams.
@@ -120,6 +131,7 @@ impl From<Config> for QuinnConfig {
         transport.allow_spin(false);
         transport.stream_receive_window(max_stream_data.into());
         transport.receive_window(max_connection_data.into());
+        transport.mtu_discovery_config(mtu_discovery_config);
         let transport = Arc::new(transport);
 
         let mut server_config = quinn::ServerConfig::with_crypto(server_tls_config);