fix(proxy): use TLS to backends for terminate-and-reencrypt routes

rust/crates/rustproxy-http/src/proxy_service.rs

@@ -344,7 +344,15 @@ impl HttpProxyService {
             }
         };
 
-        let upstream = self.upstream_selector.select(target, &peer_addr, port);
+        let mut upstream = self.upstream_selector.select(target, &peer_addr, port);
+
+        // If the route uses terminate-and-reencrypt, always re-encrypt to backend
+        if let Some(ref tls) = route_match.route.action.tls {
+            if tls.mode == rustproxy_config::TlsMode::TerminateAndReencrypt {
+                upstream.use_tls = true;
+            }
+        }
+
         let upstream_key = format!("{}:{}", upstream.host, upstream.port);
         self.upstream_selector.connection_started(&upstream_key);
 

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

@@ -185,6 +185,76 @@ pub async fn wait_for_port(port: u16, timeout_ms: u64) -> bool {
     false
 }
 
+/// Start a TLS HTTP echo backend: accepts TLS, then responds with HTTP JSON
+/// containing request details. Combines TLS acceptance with HTTP echo behavior.
+pub async fn start_tls_http_backend(
+    port: u16,
+    backend_name: &str,
+    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 name = backend_name.to_string();
+
+    let listener = TcpListener::bind(format!("127.0.0.1:{}", port))
+        .await
+        .unwrap_or_else(|_| panic!("Failed to bind TLS HTTP backend on port {}", port));
+
+    tokio::spawn(async move {
+        loop {
+            let (stream, _) = match listener.accept().await {
+                Ok(conn) => conn,
+                Err(_) => break,
+            };
+            let acc = acceptor.clone();
+            let backend = name.clone();
+            tokio::spawn(async move {
+                let mut tls_stream = match acc.accept(stream).await {
+                    Ok(s) => s,
+                    Err(_) => return,
+                };
+
+                let mut buf = vec![0u8; 16384];
+                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]);
+
+                // Parse first line: METHOD PATH HTTP/x.x
+                let first_line = req_str.lines().next().unwrap_or("");
+                let parts: Vec<&str> = first_line.split_whitespace().collect();
+                let method = parts.first().copied().unwrap_or("UNKNOWN");
+                let path = parts.get(1).copied().unwrap_or("/");
+
+                // Extract Host header
+                let host = req_str
+                    .lines()
+                    .find(|l| l.to_lowercase().starts_with("host:"))
+                    .map(|l| l[5..].trim())
+                    .unwrap_or("unknown");
+
+                let body = format!(
+                    r#"{{"method":"{}","path":"{}","host":"{}","backend":"{}"}}"#,
+                    method, path, host, backend
+                );
+
+                let response = format!(
+                    "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\nContent-Length: {}\r\nConnection: close\r\n\r\n{}",
+                    body.len(),
+                    body,
+                );
+                let _ = tls_stream.write_all(response.as_bytes()).await;
+                let _ = tls_stream.shutdown().await;
+            });
+        }
+    })
+}
+
 /// Helper to create a minimal route config for testing.
 pub fn make_test_route(
     port: u16,

rust/crates/rustproxy/tests/integration_http_proxy.rs

@@ -418,13 +418,17 @@ async fn test_terminate_and_reencrypt_http_routing() {
     let backend2_port = next_port();
     let proxy_port = next_port();
 
-    // Start plain HTTP echo backends (proxy terminates client TLS, connects plain to backend)
-    let _b1 = start_http_echo_backend(backend1_port, "alpha").await;
-    let _b2 = start_http_echo_backend(backend2_port, "beta").await;
-
     let (cert1, key1) = generate_self_signed_cert("alpha.example.com");
     let (cert2, key2) = generate_self_signed_cert("beta.example.com");
 
+    // Generate separate backend certs (backends are independent TLS servers)
+    let (backend_cert1, backend_key1) = generate_self_signed_cert("localhost");
+    let (backend_cert2, backend_key2) = generate_self_signed_cert("localhost");
+
+    // Start TLS HTTP echo backends (proxy re-encrypts to these)
+    let _b1 = start_tls_http_backend(backend1_port, "alpha", &backend_cert1, &backend_key1).await;
+    let _b2 = start_tls_http_backend(backend2_port, "beta", &backend_cert2, &backend_key2).await;
+
     // Create terminate-and-reencrypt routes
     let mut route1 = make_tls_terminate_route(
         proxy_port, "alpha.example.com", "127.0.0.1", backend1_port, &cert1, &key1,