+/**
+ * Send Window Update ACK,
+ * ensuring that it will be sent once, if RWND became non-zero,
+ * after zero RWND has been advertised in ACK before
+ */
+void
+tcp_send_window_update_ack (tcp_connection_t * tc)
+{
+ tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
+ u32 win;
+
+ if (tcp_zero_rwnd_sent (tc))
+ {
+ win = tcp_window_to_advertise (tc, tc->state);
+ if (win > 0)
+ {
+ tcp_zero_rwnd_sent_off (tc);
+ tcp_program_ack (wrk, tc);
+ }
+ }
+}
+