Function siftr_pkt_manager_thread

freebsd/netinet/siftr.c:561–636

}

static void
siftr_pkt_manager_thread(void *arg)
{
	STAILQ_HEAD(pkthead, pkt_node) tmp_pkt_queue =
	    STAILQ_HEAD_INITIALIZER(tmp_pkt_queue);
	struct pkt_node *pkt_node, *pkt_node_temp;
	uint8_t draining;

	draining = 2;

	mtx_lock(&siftr_pkt_mgr_mtx);

	/* draining == 0 when queue has been flushed and it's safe to exit. */
	while (draining) {
		/*
		 * Sleep until we are signalled to wake because thread has
		 * been told to exit or until 1 tick has passed.
		 */
		mtx_sleep(&wait_for_pkt, &siftr_pkt_mgr_mtx, PWAIT, "pktwait",
		    1);

		/* Gain exclusive access to the pkt_node queue. */
		mtx_lock(&siftr_pkt_queue_mtx);

		/*
		 * Move pkt_queue to tmp_pkt_queue, which leaves
		 * pkt_queue empty and ready to receive more pkt_nodes.
		 */
		STAILQ_CONCAT(&tmp_pkt_queue, &pkt_queue);

		/*
		 * We've finished making changes to the list. Unlock it
		 * so the pfil hooks can continue queuing pkt_nodes.
		 */
		mtx_unlock(&siftr_pkt_queue_mtx);

		/*
		 * We can't hold a mutex whilst calling siftr_process_pkt
		 * because ALQ might sleep waiting for buffer space.
		 */
		mtx_unlock(&siftr_pkt_mgr_mtx);

		/* Flush all pkt_nodes to the log file. */
		STAILQ_FOREACH_SAFE(pkt_node, &tmp_pkt_queue, nodes,
		    pkt_node_temp) {
			siftr_process_pkt(pkt_node);
			STAILQ_REMOVE_HEAD(&tmp_pkt_queue, nodes);
			free(pkt_node, M_SIFTR_PKTNODE);
		}

		KASSERT(STAILQ_EMPTY(&tmp_pkt_queue),
		    ("SIFTR tmp_pkt_queue not empty after flush"));

		mtx_lock(&siftr_pkt_mgr_mtx);

		/*
		 * If siftr_exit_pkt_manager_thread gets set during the window
		 * where we are draining the tmp_pkt_queue above, there might