Function garp_rexmit

freebsd/netinet/if_ether.c:1355–1398

* Retransmit a Gratuitous ARP (GARP) and, if necessary, schedule a callout to * retransmit it again. A pending callout owns a reference to the ifa. */

 * retransmit it again. A pending callout owns a reference to the ifa.
 */
static void
garp_rexmit(void *arg)
{
	struct in_ifaddr *ia = arg;

	if (callout_pending(&ia->ia_garp_timer) ||
	    !callout_active(&ia->ia_garp_timer)) {
		IF_ADDR_WUNLOCK(ia->ia_ifa.ifa_ifp);
		ifa_free(&ia->ia_ifa);
		return;
	}

	CURVNET_SET(ia->ia_ifa.ifa_ifp->if_vnet);

	/*
	 * Drop lock while the ARP request is generated.
	 */
	IF_ADDR_WUNLOCK(ia->ia_ifa.ifa_ifp);

	arprequest(ia->ia_ifa.ifa_ifp, &IA_SIN(ia)->sin_addr,
	    &IA_SIN(ia)->sin_addr, IF_LLADDR(ia->ia_ifa.ifa_ifp));

	/*
	 * Increment the count of retransmissions. If the count has reached the
	 * maximum value, stop sending the GARP packets. Otherwise, schedule
	 * the callout to retransmit another GARP packet.
	 */
	++ia->ia_garp_count;
	if (ia->ia_garp_count >= garp_rexmit_count) {
		ifa_free(&ia->ia_ifa);
	} else {
		int rescheduled;
		IF_ADDR_WLOCK(ia->ia_ifa.ifa_ifp);
		rescheduled = callout_reset(&ia->ia_garp_timer,
		    (1 << ia->ia_garp_count) * hz,
		    garp_rexmit, ia);
		IF_ADDR_WUNLOCK(ia->ia_ifa.ifa_ifp);
		if (rescheduled) {
			ifa_free(&ia->ia_ifa);
		}
	}

	CURVNET_RESTORE();
}

/*
 * Start the GARP retransmit timer.