Function rip_ctlinput

freebsd/netinet/raw_ip.c:811–878

* This function exists solely to receive the PRC_IFDOWN messages which are * sent by if_down(). It looks for an ifaddr whose ifa_addr is sa, and calls * in_ifadown() to remove all routes corresponding to that address. It also * receives the PRC_IFUP messages from if_up() and reinstalls the interface * routes. */

 * routes.
 */
void
rip_ctlinput(int cmd, struct sockaddr *sa, void *vip)
{
	struct rm_priotracker in_ifa_tracker;
	struct in_ifaddr *ia;
	struct ifnet *ifp;
	int err;
	int flags;

	switch (cmd) {
	case PRC_IFDOWN:
		IN_IFADDR_RLOCK(&in_ifa_tracker);
		CK_STAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) {
			if (ia->ia_ifa.ifa_addr == sa
			    && (ia->ia_flags & IFA_ROUTE)) {
				ifa_ref(&ia->ia_ifa);
				IN_IFADDR_RUNLOCK(&in_ifa_tracker);
				/*
				 * in_scrubprefix() kills the interface route.
				 */
				in_scrubprefix(ia, 0);
				/*
				 * in_ifadown gets rid of all the rest of the
				 * routes.  This is not quite the right thing
				 * to do, but at least if we are running a
				 * routing process they will come back.
				 */
				in_ifadown(&ia->ia_ifa, 0);
				ifa_free(&ia->ia_ifa);
				break;
			}
		}
		if (ia == NULL)		/* If ia matched, already unlocked. */
			IN_IFADDR_RUNLOCK(&in_ifa_tracker);
		break;

	case PRC_IFUP:
		IN_IFADDR_RLOCK(&in_ifa_tracker);
		CK_STAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) {
			if (ia->ia_ifa.ifa_addr == sa)
				break;
		}
		if (ia == NULL || (ia->ia_flags & IFA_ROUTE)) {
			IN_IFADDR_RUNLOCK(&in_ifa_tracker);
			return;
		}
		ifa_ref(&ia->ia_ifa);
		IN_IFADDR_RUNLOCK(&in_ifa_tracker);
		flags = RTF_UP;
		ifp = ia->ia_ifa.ifa_ifp;

		if ((ifp->if_flags & IFF_LOOPBACK)
		    || (ifp->if_flags & IFF_POINTOPOINT))
			flags |= RTF_HOST;

		err = ifa_del_loopback_route((struct ifaddr *)ia, sa);

		rt_addrmsg(RTM_ADD, &ia->ia_ifa, ia->ia_ifp->if_fib);