xref: /src/sys/net/route.c

/*	$NetBSD: route.c,v 1.128 2014/02/25 18:30:12 pooka Exp $	*/

/*-
 * Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Kevin M. Lahey of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Copyright (c) 1980, 1986, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)route.c	8.3 (Berkeley) 1/9/95
 */

#include "opt_route.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: route.c,v 1.128 2014/02/25 18:30:12 pooka Exp $");

#include <sys/param.h>
#include <sys/kmem.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/proc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/kernel.h>
#include <sys/ioctl.h>
#include <sys/pool.h>
#include <sys/kauth.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/raw_cb.h>

#include <netinet/in.h>
#include <netinet/in_var.h>

#ifdef RTFLUSH_DEBUG
#define	rtcache_debug() __predict_false(_rtcache_debug)
#else /* RTFLUSH_DEBUG */
#define	rtcache_debug() 0
#endif /* RTFLUSH_DEBUG */

struct	rtstat	rtstat;

int	rttrash;		/* routes not in table but not freed */

struct pool rtentry_pool;
struct pool rttimer_pool;

struct callout rt_timer_ch; /* callout for rt_timer_timer() */

#ifdef RTFLUSH_DEBUG
static int _rtcache_debug = 0;
#endif /* RTFLUSH_DEBUG */

static kauth_listener_t route_listener;

static int rtdeletemsg(struct rtentry *);
static int rtflushclone1(struct rtentry *, void *);
static void rtflushclone(sa_family_t family, struct rtentry *);

#ifdef RTFLUSH_DEBUG
static void sysctl_net_rtcache_setup(struct sysctllog **);
static void
sysctl_net_rtcache_setup(struct sysctllog **clog)
{
	const struct sysctlnode *rnode;

	if (sysctl_createv(clog, 0, NULL, &rnode, CTLFLAG_PERMANENT,
	    CTLTYPE_NODE,
	    "rtcache", SYSCTL_DESCR("Route cache related settings"),
	    NULL, 0, NULL, 0, CTL_NET, CTL_CREATE, CTL_EOL) != 0)
		return;
	if (sysctl_createv(clog, 0, &rnode, &rnode,
	    CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT,
	    "debug", SYSCTL_DESCR("Debug route caches"),
	    NULL, 0, &_rtcache_debug, 0, CTL_CREATE, CTL_EOL) != 0)
		return;
}
#endif /* RTFLUSH_DEBUG */

struct ifaddr *
rt_get_ifa(struct rtentry *rt)
{
	struct ifaddr *ifa;

	if ((ifa = rt->rt_ifa) == NULL)
		return ifa;
	else if (ifa->ifa_getifa == NULL)
		return ifa;
#if 0
	else if (ifa->ifa_seqno != NULL && *ifa->ifa_seqno == rt->rt_ifa_seqno)
		return ifa;
#endif
	else {
		ifa = (*ifa->ifa_getifa)(ifa, rt_getkey(rt));
		rt_replace_ifa(rt, ifa);
		return ifa;
	}
}

static void
rt_set_ifa1(struct rtentry *rt, struct ifaddr *ifa)
{
	rt->rt_ifa = ifa;
	if (ifa->ifa_seqno != NULL)
		rt->rt_ifa_seqno = *ifa->ifa_seqno;
}

/*
 * Is this route the connected route for the ifa?
 */
static int
rt_ifa_connected(const struct rtentry *rt, const struct ifaddr *ifa)
{
	const struct sockaddr *key, *dst, *odst;
	struct sockaddr_storage maskeddst;

	key = rt_getkey(rt);
	dst = rt->rt_flags & RTF_HOST ? ifa->ifa_dstaddr : ifa->ifa_addr;
	if (dst == NULL ||
	    dst->sa_family != key->sa_family ||
	    dst->sa_len != key->sa_len)
		return 0;
	if ((rt->rt_flags & RTF_HOST) == 0 && ifa->ifa_netmask) {
		odst = dst;
		dst = (struct sockaddr *)&maskeddst;
		rt_maskedcopy(odst, (struct sockaddr *)&maskeddst,
		    ifa->ifa_netmask);
	}
	return (memcmp(dst, key, dst->sa_len) == 0);
}

void
rt_replace_ifa(struct rtentry *rt, struct ifaddr *ifa)
{
	if (rt->rt_ifa &&
	    rt->rt_ifa != ifa &&
	    rt->rt_ifa->ifa_flags & IFA_ROUTE &&
	    rt_ifa_connected(rt, rt->rt_ifa))
	{
		RT_DPRINTF("rt->_rt_key = %p, ifa = %p, "
		    "replace deleted IFA_ROUTE\n",
		    (void *)rt->_rt_key, (void *)rt->rt_ifa);
		rt->rt_ifa->ifa_flags &= ~IFA_ROUTE;
		if (rt_ifa_connected(rt, ifa)) {
			RT_DPRINTF("rt->_rt_key = %p, ifa = %p, "
			    "replace added IFA_ROUTE\n",
			    (void *)rt->_rt_key, (void *)ifa);
			ifa->ifa_flags |= IFA_ROUTE;
		}
	}

	IFAREF(ifa);
	IFAFREE(rt->rt_ifa);
	rt_set_ifa1(rt, ifa);
}

static void
rt_set_ifa(struct rtentry *rt, struct ifaddr *ifa)
{
	IFAREF(ifa);
	rt_set_ifa1(rt, ifa);
}

static int
route_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
    void *arg0, void *arg1, void *arg2, void *arg3)
{
	struct rt_msghdr *rtm;
	int result;

	result = KAUTH_RESULT_DEFER;
	rtm = arg1;

	if (action != KAUTH_NETWORK_ROUTE)
		return result;

	if (rtm->rtm_type == RTM_GET)
		result = KAUTH_RESULT_ALLOW;

	return result;
}

void
rt_init(void)
{

#ifdef RTFLUSH_DEBUG
	sysctl_net_rtcache_setup(NULL);
#endif

	pool_init(&rtentry_pool, sizeof(struct rtentry), 0, 0, 0, "rtentpl",
	    NULL, IPL_SOFTNET);
	pool_init(&rttimer_pool, sizeof(struct rttimer), 0, 0, 0, "rttmrpl",
	    NULL, IPL_SOFTNET);

	rn_init();	/* initialize all zeroes, all ones, mask table */
	rtbl_init();

	route_listener = kauth_listen_scope(KAUTH_SCOPE_NETWORK,
	    route_listener_cb, NULL);
}

void
rtflushall(int family)
{
	struct domain *dom;

	if (rtcache_debug())
		printf("%s: enter\n", __func__);

	if ((dom = pffinddomain(family)) == NULL)
		return;

	rtcache_invalidate(&dom->dom_rtcache);
}

void
rtcache(struct route *ro)
{
	struct domain *dom;

	rtcache_invariants(ro);
	KASSERT(ro->_ro_rt != NULL);
	KASSERT(ro->ro_invalid == false);
	KASSERT(rtcache_getdst(ro) != NULL);

	if ((dom = pffinddomain(rtcache_getdst(ro)->sa_family)) == NULL)
		return;

	LIST_INSERT_HEAD(&dom->dom_rtcache, ro, ro_rtcache_next);
	rtcache_invariants(ro);
}

/*
 * Packet routing routines.
 */
struct rtentry *
rtalloc1(const struct sockaddr *dst, int report)
{
	rtbl_t *rtbl = rt_gettable(dst->sa_family);
	struct rtentry *rt;
	struct rtentry *newrt = NULL;
	struct rt_addrinfo info;
	int  s = splsoftnet(), err = 0, msgtype = RTM_MISS;

	if (rtbl != NULL && (rt = rt_matchaddr(rtbl, dst)) != NULL) {
		newrt = rt;
		if (report && (rt->rt_flags & RTF_CLONING)) {
			err = rtrequest(RTM_RESOLVE, dst, NULL, NULL, 0,
			    &newrt);
			if (err) {
				newrt = rt;
				rt->rt_refcnt++;
				goto miss;
			}
			KASSERT(newrt != NULL);
			if ((rt = newrt) && (rt->rt_flags & RTF_XRESOLVE)) {
				msgtype = RTM_RESOLVE;
				goto miss;
			}
			/* Inform listeners of the new route */
			memset(&info, 0, sizeof(info));
			info.rti_info[RTAX_DST] = rt_getkey(rt);
			info.rti_info[RTAX_NETMASK] = rt_mask(rt);
			info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
			if (rt->rt_ifp != NULL) {
				info.rti_info[RTAX_IFP] =
				    rt->rt_ifp->if_dl->ifa_addr;
				info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
			}
			rt_missmsg(RTM_ADD, &info, rt->rt_flags, 0);
		} else
			rt->rt_refcnt++;
	} else {
		rtstat.rts_unreach++;
	miss:	if (report) {
			memset((void *)&info, 0, sizeof(info));
			info.rti_info[RTAX_DST] = dst;
			rt_missmsg(msgtype, &info, 0, err);
		}
	}
	splx(s);
	return newrt;
}

void
rtfree(struct rtentry *rt)
{
	struct ifaddr *ifa;

	if (rt == NULL)
		panic("rtfree");
	rt->rt_refcnt--;
	if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_UP) == 0) {
		rt_assert_inactive(rt);
		rttrash--;
		if (rt->rt_refcnt < 0) {
			printf("rtfree: %p not freed (neg refs)\n", rt);
			return;
		}
		rt_timer_remove_all(rt, 0);
		ifa = rt->rt_ifa;
		rt->rt_ifa = NULL;
		IFAFREE(ifa);
		rt->rt_ifp = NULL;
		rt_destroy(rt);
		pool_put(&rtentry_pool, rt);
	}
}

void
ifafree(struct ifaddr *ifa)
{

#ifdef DIAGNOSTIC
	if (ifa == NULL)
		panic("ifafree: null ifa");
	if (ifa->ifa_refcnt != 0)
		panic("ifafree: ifa_refcnt != 0 (%d)", ifa->ifa_refcnt);
#endif
#ifdef IFAREF_DEBUG
	printf("ifafree: freeing ifaddr %p\n", ifa);
#endif
	free(ifa, M_IFADDR);
}

/*
 * Force a routing table entry to the specified
 * destination to go through the given gateway.
 * Normally called as a result of a routing redirect
 * message from the network layer.
 *
 * N.B.: must be called at splsoftnet
 */
void
rtredirect(const struct sockaddr *dst, const struct sockaddr *gateway,
	const struct sockaddr *netmask, int flags, const struct sockaddr *src,
	struct rtentry **rtp)
{
	struct rtentry *rt;
	int error = 0;
	uint64_t *stat = NULL;
	struct rt_addrinfo info;
	struct ifaddr *ifa;

	/* verify the gateway is directly reachable */
	if ((ifa = ifa_ifwithnet(gateway)) == NULL) {
		error = ENETUNREACH;
		goto out;
	}
	rt = rtalloc1(dst, 0);
	/*
	 * If the redirect isn't from our current router for this dst,
	 * it's either old or wrong.  If it redirects us to ourselves,
	 * we have a routing loop, perhaps as a result of an interface
	 * going down recently.
	 */
	if (!(flags & RTF_DONE) && rt &&
	     (sockaddr_cmp(src, rt->rt_gateway) != 0 || rt->rt_ifa != ifa))
		error = EINVAL;
	else if (ifa_ifwithaddr(gateway))
		error = EHOSTUNREACH;
	if (error)
		goto done;
	/*
	 * Create a new entry if we just got back a wildcard entry
	 * or the lookup failed.  This is necessary for hosts
	 * which use routing redirects generated by smart gateways
	 * to dynamically build the routing tables.
	 */
	if (rt == NULL || (rt_mask(rt) && rt_mask(rt)->sa_len < 2))
		goto create;
	/*
	 * Don't listen to the redirect if it's
	 * for a route to an interface.
	 */
	if (rt->rt_flags & RTF_GATEWAY) {
		if (((rt->rt_flags & RTF_HOST) == 0) && (flags & RTF_HOST)) {
			/*
			 * Changing from route to net => route to host.
			 * Create new route, rather than smashing route to net.
			 */
		create:
			if (rt != NULL)
				rtfree(rt);
			flags |=  RTF_GATEWAY | RTF_DYNAMIC;
			memset(&info, 0, sizeof(info));
			info.rti_info[RTAX_DST] = dst;
			info.rti_info[RTAX_GATEWAY] = gateway;
			info.rti_info[RTAX_NETMASK] = netmask;
			info.rti_ifa = ifa;
			info.rti_flags = flags;
			rt = NULL;
			error = rtrequest1(RTM_ADD, &info, &rt);
			if (rt != NULL)
				flags = rt->rt_flags;
			stat = &rtstat.rts_dynamic;
		} else {
			/*
			 * Smash the current notion of the gateway to
			 * this destination.  Should check about netmask!!!
			 */
			rt->rt_flags |= RTF_MODIFIED;
			flags |= RTF_MODIFIED;
			stat = &rtstat.rts_newgateway;
			rt_setgate(rt, gateway);
		}
	} else
		error = EHOSTUNREACH;
done:
	if (rt) {
		if (rtp != NULL && !error)
			*rtp = rt;
		else
			rtfree(rt);
	}
out:
	if (error)
		rtstat.rts_badredirect++;
	else if (stat != NULL)
		(*stat)++;
	memset(&info, 0, sizeof(info));
	info.rti_info[RTAX_DST] = dst;
	info.rti_info[RTAX_GATEWAY] = gateway;
	info.rti_info[RTAX_NETMASK] = netmask;
	info.rti_info[RTAX_AUTHOR] = src;
	rt_missmsg(RTM_REDIRECT, &info, flags, error);
}

/*
 * Delete a route and generate a message
 */
static int
rtdeletemsg(struct rtentry *rt)
{
	int error;
	struct rt_addrinfo info;

	/*
	 * Request the new route so that the entry is not actually
	 * deleted.  That will allow the information being reported to
	 * be accurate (and consistent with route_output()).
	 */
	memset(&info, 0, sizeof(info));
	info.rti_info[RTAX_DST] = rt_getkey(rt);
	info.rti_info[RTAX_NETMASK] = rt_mask(rt);
	info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
	info.rti_flags = rt->rt_flags;
	error = rtrequest1(RTM_DELETE, &info, &rt);

	rt_missmsg(RTM_DELETE, &info, info.rti_flags, error);

	/* Adjust the refcount */
	if (error == 0 && rt->rt_refcnt <= 0) {
		rt->rt_refcnt++;
		rtfree(rt);
	}
	return error;
}

static int
rtflushclone1(struct rtentry *rt, void *arg)
{
	struct rtentry *parent;

	parent = (struct rtentry *)arg;
	if ((rt->rt_flags & RTF_CLONED) != 0 && rt->rt_parent == parent)
		rtdeletemsg(rt);
	return 0;
}

static void
rtflushclone(sa_family_t family, struct rtentry *parent)
{

#ifdef DIAGNOSTIC
	if (!parent || (parent->rt_flags & RTF_CLONING) == 0)
		panic("rtflushclone: called with a non-cloning route");
#endif
	rt_walktree(family, rtflushclone1, (void *)parent);
}

/*
 * Routing table ioctl interface.
 */
int
rtioctl(u_long req, void *data, struct lwp *l)
{
	return EOPNOTSUPP;
}

struct ifaddr *
ifa_ifwithroute(int flags, const struct sockaddr *dst,
	const struct sockaddr *gateway)
{
	struct ifaddr *ifa;
	if ((flags & RTF_GATEWAY) == 0) {
		/*
		 * If we are adding a route to an interface,
		 * and the interface is a pt to pt link
		 * we should search for the destination
		 * as our clue to the interface.  Otherwise
		 * we can use the local address.
		 */
		ifa = NULL;
		if ((flags & RTF_HOST) && gateway->sa_family != AF_LINK)
			ifa = ifa_ifwithdstaddr(dst);
		if (ifa == NULL)
			ifa = ifa_ifwithaddr(gateway);
	} else {
		/*
		 * If we are adding a route to a remote net
		 * or host, the gateway may still be on the
		 * other end of a pt to pt link.
		 */
		ifa = ifa_ifwithdstaddr(gateway);
	}
	if (ifa == NULL)
		ifa = ifa_ifwithnet(gateway);
	if (ifa == NULL) {
		struct rtentry *rt = rtalloc1(dst, 0);
		if (rt == NULL)
			return NULL;
		rt->rt_refcnt--;
		if ((ifa = rt->rt_ifa) == NULL)
			return NULL;
	}
	if (ifa->ifa_addr->sa_family != dst->sa_family) {
		struct ifaddr *oifa = ifa;
		ifa = ifaof_ifpforaddr(dst, ifa->ifa_ifp);
		if (ifa == NULL)
			ifa = oifa;
	}
	return ifa;
}

int
rtrequest(int req, const struct sockaddr *dst, const struct sockaddr *gateway,
	const struct sockaddr *netmask, int flags, struct rtentry **ret_nrt)
{
	struct rt_addrinfo info;

	memset(&info, 0, sizeof(info));
	info.rti_flags = flags;
	info.rti_info[RTAX_DST] = dst;
	info.rti_info[RTAX_GATEWAY] = gateway;
	info.rti_info[RTAX_NETMASK] = netmask;
	return rtrequest1(req, &info, ret_nrt);
}

int
rt_getifa(struct rt_addrinfo *info)
{
	struct ifaddr *ifa;
	const struct sockaddr *dst = info->rti_info[RTAX_DST];
	const struct sockaddr *gateway = info->rti_info[RTAX_GATEWAY];
	const struct sockaddr *ifaaddr = info->rti_info[RTAX_IFA];
	const struct sockaddr *ifpaddr = info->rti_info[RTAX_IFP];
	int flags = info->rti_flags;

	/*
	 * ifp may be specified by sockaddr_dl when protocol address
	 * is ambiguous
	 */
	if (info->rti_ifp == NULL && ifpaddr != NULL
	    && ifpaddr->sa_family == AF_LINK &&
	    (ifa = ifa_ifwithnet(ifpaddr)) != NULL)
		info->rti_ifp = ifa->ifa_ifp;
	if (info->rti_ifa == NULL && ifaaddr != NULL)
		info->rti_ifa = ifa_ifwithaddr(ifaaddr);
	if (info->rti_ifa == NULL) {
		const struct sockaddr *sa;

		sa = ifaaddr != NULL ? ifaaddr :
		    (gateway != NULL ? gateway : dst);
		if (sa != NULL && info->rti_ifp != NULL)
			info->rti_ifa = ifaof_ifpforaddr(sa, info->rti_ifp);
		else if (dst != NULL && gateway != NULL)
			info->rti_ifa = ifa_ifwithroute(flags, dst, gateway);
		else if (sa != NULL)
			info->rti_ifa = ifa_ifwithroute(flags, sa, sa);
	}
	if ((ifa = info->rti_ifa) == NULL)
		return ENETUNREACH;
	if (ifa->ifa_getifa != NULL)
		info->rti_ifa = ifa = (*ifa->ifa_getifa)(ifa, dst);
	if (info->rti_ifp == NULL)
		info->rti_ifp = ifa->ifa_ifp;
	return 0;
}

int
rtrequest1(int req, struct rt_addrinfo *info, struct rtentry **ret_nrt)
{
	int s = splsoftnet();
	int error = 0, rc;
	struct rtentry *rt, *crt;
	rtbl_t *rtbl;
	struct ifaddr *ifa, *ifa2;
	struct sockaddr_storage maskeddst;
	const struct sockaddr *dst = info->rti_info[RTAX_DST];
	const struct sockaddr *gateway = info->rti_info[RTAX_GATEWAY];
	const struct sockaddr *netmask = info->rti_info[RTAX_NETMASK];
	int flags = info->rti_flags;
#define senderr(x) { error = x ; goto bad; }

	if ((rtbl = rt_gettable(dst->sa_family)) == NULL)
		senderr(ESRCH);
	if (flags & RTF_HOST)
		netmask = NULL;
	switch (req) {
	case RTM_DELETE:
		if (netmask) {
			rt_maskedcopy(dst, (struct sockaddr *)&maskeddst,
			    netmask);
			dst = (struct sockaddr *)&maskeddst;
		}
		if ((rt = rt_lookup(rtbl, dst, netmask)) == NULL)
			senderr(ESRCH);
		if ((rt->rt_flags & RTF_CLONING) != 0) {
			/* clean up any cloned children */
			rtflushclone(dst->sa_family, rt);
		}
		if ((rt = rt_deladdr(rtbl, dst, netmask)) == NULL)
			senderr(ESRCH);
		if (rt->rt_gwroute) {
			RTFREE(rt->rt_gwroute);
			rt->rt_gwroute = NULL;
		}
		if (rt->rt_parent) {
			rt->rt_parent->rt_refcnt--;
			rt->rt_parent = NULL;
		}
		rt->rt_flags &= ~RTF_UP;
		if ((ifa = rt->rt_ifa)) {
			if (ifa->ifa_flags & IFA_ROUTE &&
			    rt_ifa_connected(rt, ifa)) {
				RT_DPRINTF("rt->_rt_key = %p, ifa = %p, "
				    "deleted IFA_ROUTE\n",
				    (void *)rt->_rt_key, (void *)ifa);
				ifa->ifa_flags &= ~IFA_ROUTE;
			}
			if (ifa->ifa_rtrequest)
				ifa->ifa_rtrequest(RTM_DELETE, rt, info);
		}
		rttrash++;
		if (ret_nrt)
			*ret_nrt = rt;
		else if (rt->rt_refcnt <= 0) {
			rt->rt_refcnt++;
			rtfree(rt);
		}
		break;

	case RTM_RESOLVE:
		if (ret_nrt == NULL || (rt = *ret_nrt) == NULL)
			senderr(EINVAL);
		if ((rt->rt_flags & RTF_CLONING) == 0)
			senderr(EINVAL);
		ifa = rt->rt_ifa;
		flags = rt->rt_flags & ~(RTF_CLONING | RTF_STATIC);
		flags |= RTF_CLONED;
		gateway = rt->rt_gateway;
		flags |= RTF_HOST;
		goto makeroute;

	case RTM_ADD:
		if (info->rti_ifa == NULL && (error = rt_getifa(info)))
			senderr(error);
		ifa = info->rti_ifa;
	makeroute:
		/* Already at splsoftnet() so pool_get/pool_put are safe */
		rt = pool_get(&rtentry_pool, PR_NOWAIT);
		if (rt == NULL)
			senderr(ENOBUFS);
		memset(rt, 0, sizeof(*rt));
		rt->rt_flags = RTF_UP | flags;
		LIST_INIT(&rt->rt_timer);
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		if (rt_setkey(rt, dst, M_NOWAIT) == NULL ||
		    rt_setgate(rt, gateway) != 0) {
			pool_put(&rtentry_pool, rt);
			senderr(ENOBUFS);
		}
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		if (netmask) {
			rt_maskedcopy(dst, (struct sockaddr *)&maskeddst,
			    netmask);
			rt_setkey(rt, (struct sockaddr *)&maskeddst, M_NOWAIT);
			RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		} else {
			rt_setkey(rt, dst, M_NOWAIT);
			RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		}
		rt_set_ifa(rt, ifa);
		if (info->rti_info[RTAX_TAG] != NULL)
			rt_settag(rt, info->rti_info[RTAX_TAG]);
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		if (info->rti_info[RTAX_IFP] != NULL &&
		    (ifa2 = ifa_ifwithnet(info->rti_info[RTAX_IFP])) != NULL &&
		    ifa2->ifa_ifp != NULL)
			rt->rt_ifp = ifa2->ifa_ifp;
		else
			rt->rt_ifp = ifa->ifa_ifp;
		if (req == RTM_RESOLVE) {
			rt->rt_rmx = (*ret_nrt)->rt_rmx; /* copy metrics */
			rt->rt_parent = *ret_nrt;
			rt->rt_parent->rt_refcnt++;
		}
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		rc = rt_addaddr(rtbl, rt, netmask);
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		if (rc != 0 && (crt = rtalloc1(rt_getkey(rt), 0)) != NULL) {
			/* overwrite cloned route */
			if ((crt->rt_flags & RTF_CLONED) != 0) {
				rtdeletemsg(crt);
				rc = rt_addaddr(rtbl, rt, netmask);
			}
			RTFREE(crt);
			RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		}
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		if (rc != 0) {
			IFAFREE(ifa);
			if ((rt->rt_flags & RTF_CLONED) != 0 && rt->rt_parent)
				rtfree(rt->rt_parent);
			if (rt->rt_gwroute)
				rtfree(rt->rt_gwroute);
			rt_destroy(rt);
			pool_put(&rtentry_pool, rt);
			senderr(rc);
		}
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		if (ifa->ifa_rtrequest)
			ifa->ifa_rtrequest(req, rt, info);
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		if (ret_nrt) {
			*ret_nrt = rt;
			rt->rt_refcnt++;
		}
		if ((rt->rt_flags & RTF_CLONING) != 0) {
			/* clean up any cloned children */
			rtflushclone(dst->sa_family, rt);
		}
		rtflushall(dst->sa_family);
		break;
	case RTM_GET:
		if (netmask != NULL) {
			rt_maskedcopy(dst, (struct sockaddr *)&maskeddst,
			    netmask);
			dst = (struct sockaddr *)&maskeddst;
		}
		if ((rt = rt_lookup(rtbl, dst, netmask)) == NULL)
			senderr(ESRCH);
		if (ret_nrt != NULL) {
			*ret_nrt = rt;
			rt->rt_refcnt++;
		}
		break;
	}
bad:
	splx(s);
	return error;
}

int
rt_setgate(struct rtentry *rt, const struct sockaddr *gate)
{
	KASSERT(rt != rt->rt_gwroute);

	KASSERT(rt->_rt_key != NULL);
	RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);

	if (rt->rt_gwroute) {
		RTFREE(rt->rt_gwroute);
		rt->rt_gwroute = NULL;
	}
	KASSERT(rt->_rt_key != NULL);
	RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
	if (rt->rt_gateway != NULL)
		sockaddr_free(rt->rt_gateway);
	KASSERT(rt->_rt_key != NULL);
	RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
	if ((rt->rt_gateway = sockaddr_dup(gate, M_NOWAIT)) == NULL)
		return ENOMEM;
	KASSERT(rt->_rt_key != NULL);
	RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);

	if (rt->rt_flags & RTF_GATEWAY) {
		KASSERT(rt->_rt_key != NULL);
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		rt->rt_gwroute = rtalloc1(gate, 1);
		/*
		 * If we switched gateways, grab the MTU from the new
		 * gateway route if the current MTU, if the current MTU is
		 * greater than the MTU of gateway.
		 * Note that, if the MTU of gateway is 0, we will reset the
		 * MTU of the route to run PMTUD again from scratch. XXX
		 */
		KASSERT(rt->_rt_key != NULL);
		RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
		if (rt->rt_gwroute
		    && !(rt->rt_rmx.rmx_locks & RTV_MTU)
		    && rt->rt_rmx.rmx_mtu
		    && rt->rt_rmx.rmx_mtu > rt->rt_gwroute->rt_rmx.rmx_mtu) {
			rt->rt_rmx.rmx_mtu = rt->rt_gwroute->rt_rmx.rmx_mtu;
		}
	}
	KASSERT(rt->_rt_key != NULL);
	RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
	return 0;
}

void
rt_maskedcopy(const struct sockaddr *src, struct sockaddr *dst,
	const struct sockaddr *netmask)
{
	const char *netmaskp = &netmask->sa_data[0],
	           *srcp = &src->sa_data[0];
	char *dstp = &dst->sa_data[0];
	const char *maskend = (char *)dst + MIN(netmask->sa_len, src->sa_len);
	const char *srcend = (char *)dst + src->sa_len;

	dst->sa_len = src->sa_len;
	dst->sa_family = src->sa_family;

	while (dstp < maskend)
		*dstp++ = *srcp++ & *netmaskp++;
	if (dstp < srcend)
		memset(dstp, 0, (size_t)(srcend - dstp));
}

/*
 * Set up or tear down a routing table entry, normally
 * for an interface.
 */
int
rtinit(struct ifaddr *ifa, int cmd, int flags)
{
	struct rtentry *rt;
	struct sockaddr *dst, *odst;
	struct sockaddr_storage maskeddst;
	struct rtentry *nrt = NULL;
	int error;
	struct rt_addrinfo info;
	struct sockaddr_dl *sdl;
	const struct sockaddr_dl *ifsdl;

	dst = flags & RTF_HOST ? ifa->ifa_dstaddr : ifa->ifa_addr;
	if (cmd == RTM_DELETE) {
		if ((flags & RTF_HOST) == 0 && ifa->ifa_netmask) {
			/* Delete subnet route for this interface */
			odst = dst;
			dst = (struct sockaddr *)&maskeddst;
			rt_maskedcopy(odst, dst, ifa->ifa_netmask);
		}
		if ((rt = rtalloc1(dst, 0)) != NULL) {
			rt->rt_refcnt--;
			if (rt->rt_ifa != ifa)
				return (flags & RTF_HOST) ? EHOSTUNREACH
							: ENETUNREACH;
		}
	}
	memset(&info, 0, sizeof(info));
	info.rti_ifa = ifa;
	info.rti_flags = flags | ifa->ifa_flags;
	info.rti_info[RTAX_DST] = dst;
	info.rti_info[RTAX_GATEWAY] = ifa->ifa_addr;
	/*
	 * XXX here, it seems that we are assuming that ifa_netmask is NULL
	 * for RTF_HOST.  bsdi4 passes NULL explicitly (via intermediate
	 * variable) when RTF_HOST is 1.  still not sure if i can safely
	 * change it to meet bsdi4 behavior.
	 */
	if (cmd != RTM_LLINFO_UPD)
		info.rti_info[RTAX_NETMASK] = ifa->ifa_netmask;
	error = rtrequest1((cmd == RTM_LLINFO_UPD) ? RTM_GET : cmd, &info,
	    &nrt);
	if (error != 0 || (rt = nrt) == NULL)
		;
	else switch (cmd) {
	case RTM_DELETE:
		rt_newaddrmsg(cmd, ifa, error, nrt);
		if (rt->rt_refcnt <= 0) {
			rt->rt_refcnt++;
			rtfree(rt);
		}
		break;
	case RTM_LLINFO_UPD:
		rt->rt_refcnt--;
		RT_DPRINTF("%s: updating%s\n", __func__,
		    ((rt->rt_flags & RTF_LLINFO) == 0) ? " (no llinfo)" : "");

		ifsdl = ifa->ifa_ifp->if_sadl;

		if ((rt->rt_flags & RTF_LLINFO) != 0 &&
		    (sdl = satosdl(rt->rt_gateway)) != NULL &&
		    sdl->sdl_family == AF_LINK &&
		    sockaddr_dl_setaddr(sdl, sdl->sdl_len, CLLADDR(ifsdl),
		                        ifa->ifa_ifp->if_addrlen) == NULL) {
			error = EINVAL;
			break;
		}

		if (cmd == RTM_LLINFO_UPD && ifa->ifa_rtrequest != NULL)
			ifa->ifa_rtrequest(RTM_LLINFO_UPD, rt, &info);
		rt_newaddrmsg(RTM_CHANGE, ifa, error, nrt);
		break;
	case RTM_ADD:
		rt->rt_refcnt--;
		if (rt->rt_ifa != ifa) {
			printf("rtinit: wrong ifa (%p) was (%p)\n", ifa,
				rt->rt_ifa);
			if (rt->rt_ifa->ifa_rtrequest != NULL) {
				rt->rt_ifa->ifa_rtrequest(RTM_DELETE, rt,
				    &info);
			}
			rt_replace_ifa(rt, ifa);
			rt->rt_ifp = ifa->ifa_ifp;
			if (ifa->ifa_rtrequest != NULL)
				ifa->ifa_rtrequest(RTM_ADD, rt, &info);
		}
		rt_newaddrmsg(cmd, ifa, error, nrt);
		break;
	}
	return error;
}

/*
 * Route timer routines.  These routes allow functions to be called
 * for various routes at any time.  This is useful in supporting
 * path MTU discovery and redirect route deletion.
 *
 * This is similar to some BSDI internal functions, but it provides
 * for multiple queues for efficiency's sake...
 */

LIST_HEAD(, rttimer_queue) rttimer_queue_head;
static int rt_init_done = 0;

#define RTTIMER_CALLOUT(r)	do {					\
		if (r->rtt_func != NULL) {				\
			(*r->rtt_func)(r->rtt_rt, r);			\
		} else {						\
			rtrequest((int) RTM_DELETE,			\
				  rt_getkey(r->rtt_rt),			\
				  0, 0, 0, 0);				\
		}							\
	} while (/*CONSTCOND*/0)

/*
 * Some subtle order problems with domain initialization mean that
 * we cannot count on this being run from rt_init before various
 * protocol initializations are done.  Therefore, we make sure
 * that this is run when the first queue is added...
 */

void
rt_timer_init(void)
{
	assert(rt_init_done == 0);

	LIST_INIT(&rttimer_queue_head);
	callout_init(&rt_timer_ch, 0);
	callout_reset(&rt_timer_ch, hz, rt_timer_timer, NULL);
	rt_init_done = 1;
}

struct rttimer_queue *
rt_timer_queue_create(u_int timeout)
{
	struct rttimer_queue *rtq;

	if (rt_init_done == 0)
		rt_timer_init();

	R_Malloc(rtq, struct rttimer_queue *, sizeof *rtq);
	if (rtq == NULL)
		return NULL;
	memset(rtq, 0, sizeof(*rtq));

	rtq->rtq_timeout = timeout;
	TAILQ_INIT(&rtq->rtq_head);
	LIST_INSERT_HEAD(&rttimer_queue_head, rtq, rtq_link);

	return rtq;
}

void
rt_timer_queue_change(struct rttimer_queue *rtq, long timeout)
{

	rtq->rtq_timeout = timeout;
}

void
rt_timer_queue_remove_all(struct rttimer_queue *rtq, int destroy)
{
	struct rttimer *r;

	while ((r = TAILQ_FIRST(&rtq->rtq_head)) != NULL) {
		LIST_REMOVE(r, rtt_link);
		TAILQ_REMOVE(&rtq->rtq_head, r, rtt_next);
		if (destroy)
			RTTIMER_CALLOUT(r);
		/* we are already at splsoftnet */
		pool_put(&rttimer_pool, r);
		if (rtq->rtq_count > 0)
			rtq->rtq_count--;
		else
			printf("rt_timer_queue_remove_all: "
			    "rtq_count reached 0\n");
	}
}

void
rt_timer_queue_destroy(struct rttimer_queue *rtq, int destroy)
{

	rt_timer_queue_remove_all(rtq, destroy);

	LIST_REMOVE(rtq, rtq_link);

	/*
	 * Caller is responsible for freeing the rttimer_queue structure.
	 */
}

unsigned long
rt_timer_count(struct rttimer_queue *rtq)
{
	return rtq->rtq_count;
}

void
rt_timer_remove_all(struct rtentry *rt, int destroy)
{
	struct rttimer *r;

	while ((r = LIST_FIRST(&rt->rt_timer)) != NULL) {
		LIST_REMOVE(r, rtt_link);
		TAILQ_REMOVE(&r->rtt_queue->rtq_head, r, rtt_next);
		if (destroy)
			RTTIMER_CALLOUT(r);
		if (r->rtt_queue->rtq_count > 0)
			r->rtt_queue->rtq_count--;
		else
			printf("rt_timer_remove_all: rtq_count reached 0\n");
		/* we are already at splsoftnet */
		pool_put(&rttimer_pool, r);
	}
}

int
rt_timer_add(struct rtentry *rt,
	void (*func)(struct rtentry *, struct rttimer *),
	struct rttimer_queue *queue)
{
	struct rttimer *r;
	int s;

	/*
	 * If there's already a timer with this action, destroy it before
	 * we add a new one.
	 */
	LIST_FOREACH(r, &rt->rt_timer, rtt_link) {
		if (r->rtt_func == func)
			break;
	}
	if (r != NULL) {
		LIST_REMOVE(r, rtt_link);
		TAILQ_REMOVE(&r->rtt_queue->rtq_head, r, rtt_next);
		if (r->rtt_queue->rtq_count > 0)
			r->rtt_queue->rtq_count--;
		else
			printf("rt_timer_add: rtq_count reached 0\n");
	} else {
		s = splsoftnet();
		r = pool_get(&rttimer_pool, PR_NOWAIT);
		splx(s);
		if (r == NULL)
			return ENOBUFS;
	}

	memset(r, 0, sizeof(*r));

	r->rtt_rt = rt;
	r->rtt_time = time_uptime;
	r->rtt_func = func;
	r->rtt_queue = queue;
	LIST_INSERT_HEAD(&rt->rt_timer, r, rtt_link);
	TAILQ_INSERT_TAIL(&queue->rtq_head, r, rtt_next);
	r->rtt_queue->rtq_count++;

	return 0;
}

/* ARGSUSED */
void
rt_timer_timer(void *arg)
{
	struct rttimer_queue *rtq;
	struct rttimer *r;
	int s;

	s = splsoftnet();
	LIST_FOREACH(rtq, &rttimer_queue_head, rtq_link) {
		while ((r = TAILQ_FIRST(&rtq->rtq_head)) != NULL &&
		    (r->rtt_time + rtq->rtq_timeout) < time_uptime) {
			LIST_REMOVE(r, rtt_link);
			TAILQ_REMOVE(&rtq->rtq_head, r, rtt_next);
			RTTIMER_CALLOUT(r);
			pool_put(&rttimer_pool, r);
			if (rtq->rtq_count > 0)
				rtq->rtq_count--;
			else
				printf("rt_timer_timer: rtq_count reached 0\n");
		}
	}
	splx(s);

	callout_reset(&rt_timer_ch, hz, rt_timer_timer, NULL);
}

static struct rtentry *
_rtcache_init(struct route *ro, int flag)
{
	rtcache_invariants(ro);
	KASSERT(ro->_ro_rt == NULL);

	if (rtcache_getdst(ro) == NULL)
		return NULL;
	ro->ro_invalid = false;
	if ((ro->_ro_rt = rtalloc1(rtcache_getdst(ro), flag)) != NULL)
		rtcache(ro);

	rtcache_invariants(ro);
	return ro->_ro_rt;
}

struct rtentry *
rtcache_init(struct route *ro)
{
	return _rtcache_init(ro, 1);
}

struct rtentry *
rtcache_init_noclone(struct route *ro)
{
	return _rtcache_init(ro, 0);
}

struct rtentry *
rtcache_update(struct route *ro, int clone)
{
	rtcache_clear(ro);
	return _rtcache_init(ro, clone);
}

void
rtcache_copy(struct route *new_ro, const struct route *old_ro)
{
	struct rtentry *rt;

	KASSERT(new_ro != old_ro);
	rtcache_invariants(new_ro);
	rtcache_invariants(old_ro);

	if ((rt = rtcache_validate(old_ro)) != NULL)
		rt->rt_refcnt++;

	if (rtcache_getdst(old_ro) == NULL ||
	    rtcache_setdst(new_ro, rtcache_getdst(old_ro)) != 0)
		return;

	new_ro->ro_invalid = false;
	if ((new_ro->_ro_rt = rt) != NULL)
		rtcache(new_ro);
	rtcache_invariants(new_ro);
}

static struct dom_rtlist invalid_routes = LIST_HEAD_INITIALIZER(dom_rtlist);

void
rtcache_invalidate(struct dom_rtlist *rtlist)
{
	struct route *ro;

	while ((ro = LIST_FIRST(rtlist)) != NULL) {
		rtcache_invariants(ro);
		KASSERT(ro->_ro_rt != NULL);
		ro->ro_invalid = true;
		LIST_REMOVE(ro, ro_rtcache_next);
		LIST_INSERT_HEAD(&invalid_routes, ro, ro_rtcache_next);
		rtcache_invariants(ro);
	}
}

void
rtcache_clear(struct route *ro)
{
	rtcache_invariants(ro);
	if (ro->_ro_rt == NULL)
		return;

	LIST_REMOVE(ro, ro_rtcache_next);

	RTFREE(ro->_ro_rt);
	ro->_ro_rt = NULL;
	ro->ro_invalid = false;
	rtcache_invariants(ro);
}

struct rtentry *
rtcache_lookup2(struct route *ro, const struct sockaddr *dst, int clone,
    int *hitp)
{
	const struct sockaddr *odst;
	struct rtentry *rt = NULL;

	rtcache_invariants(ro);

	odst = rtcache_getdst(ro);

	if (odst == NULL)
		;
	else if (sockaddr_cmp(odst, dst) != 0)
		rtcache_free(ro);
	else if ((rt = rtcache_validate(ro)) == NULL)
		rtcache_clear(ro);

	if (rt == NULL) {
		*hitp = 0;
		if (rtcache_setdst(ro, dst) == 0)
			rt = _rtcache_init(ro, clone);
	} else
		*hitp = 1;

	rtcache_invariants(ro);

	return rt;
}

void
rtcache_free(struct route *ro)
{
	rtcache_clear(ro);
	if (ro->ro_sa != NULL) {
		sockaddr_free(ro->ro_sa);
		ro->ro_sa = NULL;
	}
	rtcache_invariants(ro);
}

int
rtcache_setdst(struct route *ro, const struct sockaddr *sa)
{
	KASSERT(sa != NULL);

	rtcache_invariants(ro);
	if (ro->ro_sa != NULL && ro->ro_sa->sa_family == sa->sa_family) {
		rtcache_clear(ro);
		if (sockaddr_copy(ro->ro_sa, ro->ro_sa->sa_len, sa) != NULL) {
			rtcache_invariants(ro);
			return 0;
		}
		sockaddr_free(ro->ro_sa);
	} else if (ro->ro_sa != NULL)
		rtcache_free(ro);	/* free ro_sa, wrong family */

	KASSERT(ro->_ro_rt == NULL);

	if ((ro->ro_sa = sockaddr_dup(sa, M_NOWAIT)) == NULL) {
		rtcache_invariants(ro);
		return ENOMEM;
	}
	rtcache_invariants(ro);
	return 0;
}

const struct sockaddr *
rt_settag(struct rtentry *rt, const struct sockaddr *tag)
{
	if (rt->rt_tag != tag) {
		if (rt->rt_tag != NULL)
			sockaddr_free(rt->rt_tag);
		rt->rt_tag = sockaddr_dup(tag, M_NOWAIT);
	}
	return rt->rt_tag;
}

struct sockaddr *
rt_gettag(struct rtentry *rt)
{
	return rt->rt_tag;
}