Function in_handle_ifaddr_route

freebsd/netinet/in.c:853–892

* Adds or delete interface "prefix" route corresponding to @ifa. * Returns 0 on success or errno. */

 *  Returns 0 on success or errno.
 */
int
in_handle_ifaddr_route(int cmd, struct in_ifaddr *ia)
{
	struct ifaddr *ifa = &ia->ia_ifa;
	struct in_addr daddr, maddr;
	struct sockaddr_in *pmask;
	struct epoch_tracker et;
	int error;

	ia_getrtprefix(ia, &daddr, &maddr);

	struct sockaddr_in mask = {
		.sin_family = AF_INET,
		.sin_len = sizeof(struct sockaddr_in),
		.sin_addr = maddr,
	};

	pmask = (maddr.s_addr != INADDR_BROADCAST) ? &mask : NULL;

	struct sockaddr_in dst = {
		.sin_family = AF_INET,
		.sin_len = sizeof(struct sockaddr_in),
		.sin_addr.s_addr = daddr.s_addr & maddr.s_addr,
	};

	struct ifnet *ifp = ia->ia_ifp;

	if ((maddr.s_addr == INADDR_BROADCAST) &&
	    (!(ia->ia_ifp->if_flags & (IFF_POINTOPOINT|IFF_LOOPBACK)))) {
		/* Case 2: host route on broadcast interface */
		ifp = V_loif;
	}

	uint32_t fibnum = ifa->ifa_ifp->if_fib;
	NET_EPOCH_ENTER(et);
	error = in_handle_prefix_route(fibnum, cmd, &dst, pmask, ifa, ifp);
	NET_EPOCH_EXIT(et);

	return (error);
}

/*
 * Check if we have a route for the given prefix already.