feat(s2n-tls-hyper): Add support for negotiating HTTP/2 (#4924)

bindings/rust/s2n-tls-hyper/Cargo.toml

@@ -16,12 +16,17 @@ default = []
 s2n-tls = { version = "=0.3.7", path = "../s2n-tls" }
 s2n-tls-tokio = { version = "=0.3.7", path = "../s2n-tls-tokio" }
 hyper = { version = "1" }
-hyper-util = { version = "0.1", features = ["client-legacy", "tokio", "http1"] }
+hyper-util = { version = "0.1", features = ["client-legacy", "tokio", "http1", "http2"] }
 tower-service = { version = "0.3" }
-http = { version= "1" }
+http = { version = "1" }
 
 [dev-dependencies]
 tokio = { version = "1", features = ["macros", "test-util"] }
 http-body-util = "0.1"
 hyper-util = { version = "0.1", features = ["server"] }
 bytes = "1"
+
+# Newer versions require Rust 1.65, see https://github.com/aws/s2n-tls/issues/4242.
+hashbrown = { version = "=0.15.0" }
+# Newer versions require Rust 1.70, see https://github.com/aws/s2n-tls/issues/4395.
+tokio-util = { version = "=0.7.11" }

bindings/rust/s2n-tls-hyper/src/connector.rs

@@ -41,6 +41,10 @@ where
     ///
     /// This API creates an `HttpsConnector` using the default hyper `HttpConnector`. To use an
     /// existing HTTP connector, use `HttpsConnector::new_with_http()`.
+    ///
+    /// Note that s2n-tls-hyper will override the ALPN extension to negotiate HTTP. Any ALPN values
+    /// configured on `conn_builder` with APIs like
+    /// `s2n_tls::config::Builder::set_application_protocol_preference()` will be ignored.
     pub fn new(conn_builder: Builder) -> HttpsConnector<HttpConnector, Builder> {
         let mut http = HttpConnector::new();
 
@@ -77,6 +81,10 @@ where
     /// ```
     ///
     /// `HttpsConnector::new()` can be used to create the HTTP connector automatically.
+    ///
+    /// Note that s2n-tls-hyper will override the ALPN extension to negotiate HTTP. Any ALPN values
+    /// configured on `conn_builder` with APIs like
+    /// `s2n_tls::config::Builder::set_application_protocol_preference()` will be ignored.
     pub fn new_with_http(http: Http, conn_builder: Builder) -> HttpsConnector<Http, Builder> {
         Self { http, conn_builder }
     }
@@ -118,6 +126,22 @@ where
             return Box::pin(async move { Err(Error::InvalidScheme) });
         }
 
+        // Attempt to negotiate HTTP/2 by including it in the ALPN extension. Other supported HTTP
+        // versions are also included to prevent the server from rejecting the TLS connection if
+        // HTTP/2 isn't supported:
+        //
+        // https://datatracker.ietf.org/doc/html/rfc7301#section-3.2
+        //    In the event that the server supports no
+        //    protocols that the client advertises, then the server SHALL respond
+        //    with a fatal "no_application_protocol" alert.
+        let builder = connection::ModifiedBuilder::new(self.conn_builder.clone(), |conn| {
+            conn.set_application_protocol_preference([
+                b"h2".to_vec(),
+                b"http/1.1".to_vec(),
+                b"http/1.0".to_vec(),
+            ])
+        });
+
         // IPv6 addresses are enclosed in square brackets within the host of a URI (e.g.
         // `https://[::1:2:3:4]/`). These square brackets aren't part of the domain itself, so they
         // are trimmed off to provide the proper server name to s2n-tls-tokio (e.g. `::1:2:3:4`).
@@ -129,7 +153,6 @@ where
         }
         let domain = domain.to_owned();
 
-        let builder = self.conn_builder.clone();
         let call = self.http.call(req);
         Box::pin(async move {
             // `HttpsConnector` wraps an HTTP connector that also implements `Service<Uri>`.

bindings/rust/s2n-tls-hyper/src/stream.rs

@@ -48,7 +48,15 @@ where
 {
     fn connected(&self) -> Connected {
         match self {
-            MaybeHttpsStream::Https(stream) => stream.inner().get_ref().connected(),
+            MaybeHttpsStream::Https(stream) => {
+                let connected = stream.inner().get_ref().connected();
+                let conn = stream.inner().as_ref();
+                match conn.application_protocol() {
+                    // Inform hyper that HTTP/2 was negotiated in the ALPN.
+                    Some(b"h2") => connected.negotiated_h2(),
+                    _ => connected,
+                }
+            }
         }
     }
 }

bindings/rust/s2n-tls-hyper/tests/http.rs

@@ -4,7 +4,7 @@
 use crate::common::InsecureAcceptAllCertificatesHandler;
 use bytes::Bytes;
 use common::echo::serve_echo;
-use http::{Method, Request, Uri};
+use http::{Method, Request, Uri, Version};
 use http_body_util::{BodyExt, Empty, Full};
 use hyper_util::{client::legacy::Client, rt::TokioExecutor};
 use s2n_tls::{
@@ -264,3 +264,69 @@ async fn ipv6() -> Result<(), Box<dyn Error + Send + Sync>> {
 
     Ok(())
 }
+
+#[tokio::test]
+async fn http2() -> Result<(), Box<dyn Error + Send + Sync>> {
+    for expected_http_version in [Version::HTTP_11, Version::HTTP_2] {
+        let server_config = {
+            let mut builder = common::config()?;
+            if expected_http_version == Version::HTTP_2 {
+                builder.set_application_protocol_preference(["h2"])?;
+            }
+            builder.build()?
+        };
+
+        common::echo::make_echo_request(server_config.clone(), |port| async move {
+            let connector = HttpsConnector::new(common::config()?.build()?);
+            let client: Client<_, Empty<Bytes>> =
+                Client::builder(TokioExecutor::new()).build(connector);
+
+            let uri = Uri::from_str(format!("https://localhost:{}", port).as_str())?;
+            let response = client.get(uri).await?;
+            assert_eq!(response.status(), 200);
+
+            // Ensure that HTTP/2 is negotiated when supported by the server.
+            assert_eq!(response.version(), expected_http_version);
+
+            Ok(())
+        })
+        .await?;
+    }
+
+    Ok(())
+}
+
+/// Ensure that HTTP/2 is negotiated, regardless of any pre-configured ALPN values.
+#[tokio::test]
+async fn config_alpn_ignored() -> Result<(), Box<dyn Error + Send + Sync>> {
+    let server_config = {
+        let mut builder = common::config()?;
+        builder.set_application_protocol_preference(["h2"])?;
+        builder.build()?
+    };
+
+    common::echo::make_echo_request(server_config, |port| async move {
+        let client_config = {
+            let mut builder = common::config()?;
+            // Set an arbitrary non-HTTP/2 ALPN value.
+            builder.set_application_protocol_preference([b"http/1.1"])?;
+            builder.build()?
+        };
+
+        let connector = HttpsConnector::new(client_config);
+        let client: Client<_, Empty<Bytes>> =
+            Client::builder(TokioExecutor::new()).build(connector);
+
+        let uri = Uri::from_str(format!("https://localhost:{}", port).as_str())?;
+        let response = client.get(uri).await?;
+        assert_eq!(response.status(), 200);
+
+        // Ensure that HTTP/2 was negotiated.
+        assert_eq!(response.version(), Version::HTTP_2);
+
+        Ok(())
+    })
+    .await?;
+
+    Ok(())
+}