fix(rustproxy-http): preserve original Host header when proxying and add X-Forwarded-* headers; add TLS WebSocket echo backend helper and integration test for terminate-and-reencrypt websocket

rust/crates/rustproxy/tests/common/mod.rs

@@ -452,6 +452,86 @@ pub fn make_tls_terminate_route(
     route
 }
 
+/// Start a TLS WebSocket echo backend: accepts TLS, performs WS handshake, then echoes data.
+/// Combines TLS acceptance (like `start_tls_http_backend`) with WebSocket echo (like `start_ws_echo_backend`).
+pub async fn start_tls_ws_echo_backend(
+    port: u16,
+    cert_pem: &str,
+    key_pem: &str,
+) -> JoinHandle<()> {
+    use std::sync::Arc;
+
+    let acceptor = rustproxy_passthrough::build_tls_acceptor(cert_pem, key_pem)
+        .expect("Failed to build TLS acceptor");
+    let acceptor = Arc::new(acceptor);
+
+    let listener = TcpListener::bind(format!("127.0.0.1:{}", port))
+        .await
+        .unwrap_or_else(|_| panic!("Failed to bind TLS WS echo backend on port {}", port));
+
+    tokio::spawn(async move {
+        loop {
+            let (stream, _) = match listener.accept().await {
+                Ok(conn) => conn,
+                Err(_) => break,
+            };
+            let acc = acceptor.clone();
+            tokio::spawn(async move {
+                let mut tls_stream = match acc.accept(stream).await {
+                    Ok(s) => s,
+                    Err(_) => return,
+                };
+
+                // Read the HTTP upgrade request
+                let mut buf = vec![0u8; 4096];
+                let n = match tls_stream.read(&mut buf).await {
+                    Ok(0) | Err(_) => return,
+                    Ok(n) => n,
+                };
+
+                let req_str = String::from_utf8_lossy(&buf[..n]);
+
+                // Extract Sec-WebSocket-Key for handshake
+                let ws_key = req_str
+                    .lines()
+                    .find(|l| l.to_lowercase().starts_with("sec-websocket-key:"))
+                    .map(|l| l.split(':').nth(1).unwrap_or("").trim().to_string())
+                    .unwrap_or_default();
+
+                // Send 101 Switching Protocols
+                let accept_response = format!(
+                    "HTTP/1.1 101 Switching Protocols\r\n\
+                     Upgrade: websocket\r\n\
+                     Connection: Upgrade\r\n\
+                     Sec-WebSocket-Accept: {}\r\n\
+                     \r\n",
+                    ws_key
+                );
+
+                if tls_stream
+                    .write_all(accept_response.as_bytes())
+                    .await
+                    .is_err()
+                {
+                    return;
+                }
+
+                // Echo all data back (raw TCP after upgrade)
+                let mut echo_buf = vec![0u8; 65536];
+                loop {
+                    let n = match tls_stream.read(&mut echo_buf).await {
+                        Ok(0) | Err(_) => break,
+                        Ok(n) => n,
+                    };
+                    if tls_stream.write_all(&echo_buf[..n]).await.is_err() {
+                        break;
+                    }
+                }
+            });
+        }
+    })
+}
+
 /// Helper to create a TLS passthrough route for testing.
 pub fn make_tls_passthrough_route(
     port: u16,