refine the connection close

src/redir.c

@@ -164,10 +164,8 @@ static void server_recv_cb(EV_P_ ev_io *w, int revents)
         // connection closed
         remote->buf_len = 0;
         remote->buf_idx = 0;
+        close_and_free_remote(EV_A_ remote);
         close_and_free_server(EV_A_ server);
-        if (remote != NULL) {
-            ev_io_start(EV_A_ & remote->send_ctx->io);
-        }
         return;
     } else if (r < 0) {
         if (errno == EAGAIN || errno == EWOULDBLOCK) {
@@ -425,13 +423,7 @@ static void remote_send_cb(EV_P_ ev_io *w, int revents)
                 remote->buf_len = 0;
                 remote->buf_idx = 0;
                 ev_io_stop(EV_A_ & remote_send_ctx->io);
-                if (server != NULL) {
-                    ev_io_start(EV_A_ & server->recv_ctx->io);
-                } else {
-                    close_and_free_remote(EV_A_ remote);
-                    close_and_free_server(EV_A_ server);
-                    return;
-                }
+                ev_io_start(EV_A_ & server->recv_ctx->io);
             }
         }