Try to fix duplicate Host header issue

- disable http2 to backend connections even when using tls
- forbid hyper from adding a host header

src/reverse_proxy.rs

@@ -22,7 +22,7 @@ pub const PROXY_TIMEOUT: Duration = Duration::from_secs(60);
 
 const HOP_HEADERS: &[HeaderName] = &[
 	header::CONNECTION,
-	//header::KEEP_ALIVE,
+	// header::KEEP_ALIVE, // not found in http::header
 	header::PROXY_AUTHENTICATE,
 	header::PROXY_AUTHORIZATION,
 	header::TE,
@@ -69,7 +69,8 @@ fn create_proxied_request<B>(
 ) -> Result<Request<B>> {
 	let mut builder = Request::builder()
 		.method(request.method())
-		.uri(forward_uri(forward_url, &request)?);
+		.uri(forward_uri(forward_url, &request)?)
+		.version(hyper::Version::HTTP_11);
 
 	*builder.headers_mut().unwrap() = remove_hop_headers(request.headers());
 
@@ -133,7 +134,7 @@ pub async fn call(
 	let mut connector = HttpConnector::new();
 	connector.set_connect_timeout(Some(PROXY_TIMEOUT));
 
-	let client: Client<_, hyper::Body> = Client::builder().build(connector);
+	let client: Client<_, hyper::Body> = Client::builder().set_host(false).build(connector);
 
 	let response = client.request(proxied_request).await?;
 
@@ -161,7 +162,7 @@ pub async fn call_https(
 	http_connector.set_connect_timeout(Some(PROXY_TIMEOUT));
 	let connector = HttpsConnectorFixedDnsname::new(tls_config, "dummy", http_connector);
 
-	let client: Client<_, hyper::Body> = Client::builder().build(connector);
+	let client: Client<_, hyper::Body> = Client::builder().set_host(false).build(connector);
 	let response = client.request(proxied_request).await?;
 
 	trace!("Inner response (HTTPS): {:?}", response);

src/tls_util.rs

@@ -21,7 +21,9 @@ pub struct HttpsConnectorFixedDnsname<T> {
 	tls_config: Arc<rustls::ClientConfig>,
 	fixed_dnsname: &'static str,
 }
+
 type BoxError = Box<dyn std::error::Error + Send + Sync>;
+
 impl HttpsConnectorFixedDnsname<HttpConnector> {
 	pub fn new(
 		mut tls_config: rustls::ClientConfig,
@@ -29,7 +31,7 @@ impl HttpsConnectorFixedDnsname<HttpConnector> {
 		mut http: HttpConnector,
 	) -> Self {
 		http.enforce_http(false);
-		tls_config.alpn_protocols = vec![b"h2".to_vec(), b"http/1.1".to_vec()];
+		tls_config.alpn_protocols = vec![b"http/1.1".to_vec()];
 		Self {
 			http,
 			tls_config: Arc::new(tls_config),
@@ -37,6 +39,7 @@ impl HttpsConnectorFixedDnsname<HttpConnector> {
 		}
 	}
 }
+
 impl<T> Service<Uri> for HttpsConnectorFixedDnsname<T>
 where
 	T: Service<Uri>,