feat(h2): implement the extended CONNECT protocol from RFC 8441

Cargo.toml

@@ -252,3 +252,6 @@ required-features = ["full"]
 name = "server"
 path = "tests/server.rs"
 required-features = ["full"]
+
+[patch.crates-io]
+h2 = { git = "https://github.com/hyperium/h2.git", branch = "rfc8441" }

src/client/conn.rs

@@ -486,6 +486,22 @@ where
             Poll::Ready(Ok(conn.take().unwrap().into_parts()))
         })
     }
+
+    /// Returns whether the [extended CONNECT protocol][1] is enabled or not.
+    ///
+    /// This setting is configured by the server peer by sending the
+    /// [`SETTINGS_ENABLE_CONNECT_PROTOCOL` parameter][2] in a `SETTINGS` frame.
+    /// This method returns the currently acknowledged value recieved from the
+    /// remote.
+    ///
+    /// [1]: https://datatracker.ietf.org/doc/html/rfc8441#section-4
+    /// [2]: https://datatracker.ietf.org/doc/html/rfc8441#section-3
+    pub fn http2_is_extended_connect_protocol_enabled(&self) -> bool {
+        match self.inner.as_ref().unwrap() {
+            ProtoClient::H1 { .. } => false,
+            ProtoClient::H2 { h2 } => h2.is_extended_connect_protocol_enabled(),
+        }
+    }
 }
 
 impl<T, B> Future for Connection<T, B>

src/ext.rs

@@ -1,10 +1,13 @@
-//! HTTP extensions
+//! HTTP extensions.
 
 use bytes::Bytes;
 #[cfg(feature = "http1")]
 use http::header::{HeaderName, IntoHeaderName, ValueIter};
 use http::HeaderMap;
 
+#[cfg(feature = "http2")]
+pub use h2::ext::Protocol;
+
 /// A map from header names to their original casing as received in an HTTP message.
 ///
 /// If an HTTP/1 response `res` is parsed on a connection whose option

src/lib.rs

@@ -76,7 +76,7 @@ mod cfg;
 mod common;
 pub mod body;
 mod error;
-mod ext;
+pub mod ext;
 #[cfg(test)]
 mod mock;
 pub mod rt;

src/proto/h2/client.rs

@@ -200,6 +200,15 @@ where
     req_rx: ClientRx<B>,
 }
 
+impl<B> ClientTask<B>
+where
+    B: HttpBody + 'static,
+{
+    pub(crate) fn is_extended_connect_protocol_enabled(&self) -> bool {
+        self.h2_tx.is_extended_connect_protocol_enabled()
+    }
+}
+
 impl<B> Future for ClientTask<B>
 where
     B: HttpBody + Send + 'static,

src/proto/h2/server.rs

@@ -40,6 +40,7 @@ pub(crate) struct Config {
     pub(crate) initial_conn_window_size: u32,
     pub(crate) initial_stream_window_size: u32,
     pub(crate) max_frame_size: u32,
+    pub(crate) enable_connect_protocol: bool,
     pub(crate) max_concurrent_streams: Option<u32>,
     #[cfg(feature = "runtime")]
     pub(crate) keep_alive_interval: Option<Duration>,
@@ -54,6 +55,7 @@ impl Default for Config {
             initial_conn_window_size: DEFAULT_CONN_WINDOW,
             initial_stream_window_size: DEFAULT_STREAM_WINDOW,
             max_frame_size: DEFAULT_MAX_FRAME_SIZE,
+            enable_connect_protocol: false,
             max_concurrent_streams: None,
             #[cfg(feature = "runtime")]
             keep_alive_interval: None,
@@ -113,6 +115,9 @@ where
         if let Some(max) = config.max_concurrent_streams {
             builder.max_concurrent_streams(max);
         }
+        if config.enable_connect_protocol {
+            builder.enable_connect_protocol();
+        }
         let handshake = builder.handshake(io);
 
         let bdp = if config.adaptive_window {

src/server/conn.rs

@@ -500,6 +500,15 @@ impl<E> Http<E> {
         self
     }
 
+    /// Enables the [extended CONNECT protocol].
+    ///
+    /// [extended CONNECT protocol]: https://datatracker.ietf.org/doc/html/rfc8441#section-4
+    #[cfg(feature = "http2")]
+    pub fn http2_enable_connect_protocol(&mut self) -> &mut Self {
+        self.h2_builder.enable_connect_protocol = true;
+        self
+    }
+
     /// Set the maximum buffer size for the connection.
     ///
     /// Default is ~400kb.

src/server/server.rs

@@ -403,6 +403,15 @@ impl<I, E> Builder<I, E> {
         self
     }
 
+    /// Enables the [extended CONNECT protocol].
+    ///
+    /// [extended CONNECT protocol]: https://datatracker.ietf.org/doc/html/rfc8441#section-4
+    #[cfg(feature = "http2")]
+    pub fn http2_enable_connect_protocol(mut self) -> Self {
+        self.protocol.http2_enable_connect_protocol();
+        self
+    }
+
     /// Sets the `Executor` to deal with connection tasks.
     ///
     /// Default is `tokio::spawn`.