/*
 * Look up the route that matches the given "dst" address.
 *
 * Route lookup can have the side-effect of creating and returning
 * a cloned route instead when "dst" matches a cloning route and the
 * RTF_CLONING and RTF_PRCLONING flags are not being ignored.
 *
 * Any route returned has its reference count incremented.
 */
struct rtentry *
_rtlookup(struct sockaddr *dst, boolean_t generate_report, u_long ignore)
{
	struct radix_node_head *rnh = rt_tables[dst->sa_family];
	struct rtentry *rt;

	if (rnh == NULL)
		goto unreach;

	/*
	 * Look up route in the radix tree.
	 */
	rt = (struct rtentry *) rnh->rnh_matchaddr((char *)dst, rnh);
	if (rt == NULL)
		goto unreach;

	/*
	 * Handle cloning routes.
	 */
	if ((rt->rt_flags & ~ignore & (RTF_CLONING | RTF_PRCLONING)) != 0) {
		struct rtentry *clonedroute;
		int error;

		clonedroute = rt;	/* copy in/copy out parameter */
		error = rtrequest(RTM_RESOLVE, dst, NULL, NULL, 0,
				  &clonedroute);	/* clone the route */
		if (error != 0) {	/* cloning failed */
			if (generate_report)
				rt_dstmsg(RTM_MISS, dst, error);
			rt->rt_refcnt++;
			return (rt);	/* return the uncloned route */
		}
		if (generate_report) {
			if (clonedroute->rt_flags & RTF_XRESOLVE)
				rt_dstmsg(RTM_RESOLVE, dst, 0);
			else
				rt_rtmsg(RTM_ADD, clonedroute,
					 clonedroute->rt_ifp, 0);
		}
		return (clonedroute);	/* return cloned route */
	}

	/*
	 * Increment the reference count of the matched route and return.
	 */
	rt->rt_refcnt++;
	return (rt);

unreach:
	rtstat.rts_unreach++;
	if (generate_report)
		rt_dstmsg(RTM_MISS, dst, 0);
	return (NULL);
}