shrpx: Don't return chunked response for pre-HTTP/1.1 request

src/shrpx_spdy_session.cc

@@ -591,11 +591,20 @@ void on_ctrl_recv_callback
       status = downstream->get_response_http_status();
       if(!((100 <= status && status <= 199) || status == 204 ||
            status == 304)) {
-        // In SPDY, we are supporsed not to receive
-        // transfer-encoding.
+        // Here we have response body but Content-Length is not known
+        // in advance.
+        if(downstream->get_request_major() <= 0 ||
+           downstream->get_request_minor() <= 0) {
+          // We simply close connection for pre-HTTP/1.1 in this case.
+          downstream->set_response_connection_close(true);
+        } else {
+          // Otherwise, use chunked encoding to keep upstream
+          // connection open.  In SPDY, we are supporsed not to
+          // receive transfer-encoding.
           downstream->add_response_header("transfer-encoding", "chunked");
         }
       }
+    }
 
     if(LOG_ENABLED(INFO)) {
       std::stringstream ss;