Function ng_pptpgre_send_ack_timeout

freebsd/netgraph/ng_pptpgre.c:1137–1146

* We've waited as long as we're willing to wait before sending an * acknowledgement to the peer for received frames. We had hoped to * be able to piggy back our acknowledgement on an outgoing data frame, * but apparently there haven't been any since. So send the ack now. */

 * but apparently there haven't been any since. So send the ack now.
 */
static void
ng_pptpgre_send_ack_timeout(node_p node, hook_p hook, void *arg1, int arg2)
{
	const hpriv_p hpriv = arg1;

	mtx_lock(&hpriv->mtx);
	/* Send a frame with an ack but no payload */
  	ng_pptpgre_xmit(hpriv, NULL);
	mtx_assert(&hpriv->mtx, MA_NOTOWNED);
}

/*
 * Start a timer for the reorder queue. This assumes the timer is not