[unix-history] / usr / src / sbin / routed / tables.c

/*
 * Copyright (c) 1983, 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static char sccsid[] = "@(#)tables.c	5.14 (Berkeley) %G%";
#endif /* not lint */

/*
 * Routing Table Management Daemon
 */
#include "defs.h"
#include <sys/ioctl.h>
#include <errno.h>
#include <sys/syslog.h>

#ifndef DEBUG
#define	DEBUG	0
#endif

int	install = !DEBUG;		/* if 1 call kernel */

/*
 * Lookup dst in the tables for an exact match.
 */
struct rt_entry *
rtlookup(dst)
	struct sockaddr *dst;
{
	register struct rt_entry *rt;
	register struct rthash *rh;
	register u_int hash;
	struct afhash h;
	int doinghost = 1;

	if (dst->sa_family >= af_max)
		return (0);
	(*afswitch[dst->sa_family].af_hash)(dst, &h);
	hash = h.afh_hosthash;
	rh = &hosthash[hash & ROUTEHASHMASK];
again:
	for (rt = rh->rt_forw; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
		if (rt->rt_hash != hash)
			continue;
		if (equal(&rt->rt_dst, dst))
			return (rt);
	}
	if (doinghost) {
		doinghost = 0;
		hash = h.afh_nethash;
		rh = &nethash[hash & ROUTEHASHMASK];
		goto again;
	}
	return (0);
}

struct sockaddr wildcard;	/* zero valued cookie for wildcard searches */

/*
 * Find a route to dst as the kernel would.
 */
struct rt_entry *
rtfind(dst)
	struct sockaddr *dst;
{
	register struct rt_entry *rt;
	register struct rthash *rh;
	register u_int hash;
	struct afhash h;
	int af = dst->sa_family;
	int doinghost = 1, (*match)();

	if (af >= af_max)
		return (0);
	(*afswitch[af].af_hash)(dst, &h);
	hash = h.afh_hosthash;
	rh = &hosthash[hash & ROUTEHASHMASK];

again:
	for (rt = rh->rt_forw; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
		if (rt->rt_hash != hash)
			continue;
		if (doinghost) {
			if (equal(&rt->rt_dst, dst))
				return (rt);
		} else {
			if (rt->rt_dst.sa_family == af &&
			    (*match)(&rt->rt_dst, dst))
				return (rt);
		}
	}
	if (doinghost) {
		doinghost = 0;
		hash = h.afh_nethash;
		rh = &nethash[hash & ROUTEHASHMASK];
		match = afswitch[af].af_netmatch;
		goto again;
	}
#ifdef notyet
	/*
	 * Check for wildcard gateway, by convention network 0.
	 */
	if (dst != &wildcard) {
		dst = &wildcard, hash = 0;
		goto again;
	}
#endif
	return (0);
}

rtadd(dst, gate, metric, state)
	struct sockaddr *dst, *gate;
	int metric, state;
{
	struct afhash h;
	register struct rt_entry *rt;
	struct rthash *rh;
	int af = dst->sa_family, flags;
	u_int hash;

	if (af >= af_max)
		return;
	(*afswitch[af].af_hash)(dst, &h);
	flags = (*afswitch[af].af_rtflags)(dst);
	/*
	 * Subnet flag isn't visible to kernel, move to state.	XXX
	 */
	if (flags & RTF_SUBNET) {
		state |= RTS_SUBNET;
		flags &= ~RTF_SUBNET;
	}
	if (flags & RTF_HOST) {
		hash = h.afh_hosthash;
		rh = &hosthash[hash & ROUTEHASHMASK];
	} else {
		hash = h.afh_nethash;
		rh = &nethash[hash & ROUTEHASHMASK];
	}
	rt = (struct rt_entry *)malloc(sizeof (*rt));
	if (rt == 0)
		return;
	rt->rt_hash = hash;
	rt->rt_dst = *dst;
	rt->rt_router = *gate;
	rt->rt_timer = 0;
	rt->rt_flags = RTF_UP | flags;
	rt->rt_state = state | RTS_CHANGED;
	rt->rt_ifp = if_ifwithdstaddr(&rt->rt_router);
	if (rt->rt_ifp == 0)
		rt->rt_ifp = if_ifwithnet(&rt->rt_router);
	if ((state & RTS_INTERFACE) == 0)
		rt->rt_flags |= RTF_GATEWAY;
	rt->rt_metric = metric;
	insque(rt, rh);
	TRACE_ACTION("ADD", rt);
	/*
	 * If the ioctl fails because the gateway is unreachable
	 * from this host, discard the entry.  This should only
	 * occur because of an incorrect entry in /etc/gateways.
	 */
	if (install && (rt->rt_state & (RTS_INTERNAL | RTS_EXTERNAL)) == 0 &&
	    ioctl(s, SIOCADDRT, (char *)&rt->rt_rt) < 0) {
		if (errno != EEXIST && gate->sa_family < af_max)
			syslog(LOG_ERR,
			"adding route to net/host %s through gateway %s: %m\n",
			   (*afswitch[dst->sa_family].af_format)(dst),
			   (*afswitch[gate->sa_family].af_format)(gate));
		perror("SIOCADDRT");
		if (errno == ENETUNREACH) {
			TRACE_ACTION("DELETE", rt);
			remque(rt);
			free((char *)rt);
		}
	}
}

rtchange(rt, gate, metric)
	struct rt_entry *rt;
	struct sockaddr *gate;
	short metric;
{
	int add = 0, delete = 0;
	struct rtentry oldroute;

	if ((rt->rt_state & RTS_INTERNAL) == 0) {
		/*
		 * If changing to different router, we need to add
		 * new route and delete old one if in the kernel.
		 * If the router is the same, we need to delete
		 * the route if has become unreachable, or re-add
		 * it if it had been unreachable.
		 */
		if (!equal(&rt->rt_router, gate)) {
			add++;
			if (rt->rt_metric != HOPCNT_INFINITY)
				delete++;
		} else if (metric == HOPCNT_INFINITY)
			delete++;
		else if (rt->rt_metric == HOPCNT_INFINITY)
			add++;
	}
	if (!equal(&rt->rt_router, gate)) {
		TRACE_ACTION("CHANGE FROM ", rt);
	} else if (metric != rt->rt_metric)
		TRACE_NEWMETRIC(rt, metric);
	if (delete)
		oldroute = rt->rt_rt;
	if ((rt->rt_state & RTS_INTERFACE) && delete) {
		rt->rt_state &= ~RTS_INTERFACE;
		rt->rt_flags |= RTF_GATEWAY;
		if (metric > rt->rt_metric && delete)
			syslog(LOG_ERR, "%s route to interface %s (timed out)",
			    add? "changing" : "deleting",
			    rt->rt_ifp->int_name);
	}
	if (add) {
		rt->rt_router = *gate;
		rt->rt_ifp = if_ifwithdstaddr(&rt->rt_router);
		if (rt->rt_ifp == 0)
			rt->rt_ifp = if_ifwithnet(&rt->rt_router);
	}
	rt->rt_metric = metric;
	rt->rt_state |= RTS_CHANGED;
	if (add)
		TRACE_ACTION("CHANGE TO   ", rt);
	if (add && install)
		if (ioctl(s, SIOCADDRT, (char *)&rt->rt_rt) < 0)
			perror("SIOCADDRT");
	if (delete && install)
		if (ioctl(s, SIOCDELRT, (char *)&oldroute) < 0)
			perror("SIOCDELRT");
}

rtdelete(rt)
	struct rt_entry *rt;
{

	TRACE_ACTION("DELETE", rt);
	if (rt->rt_metric < HOPCNT_INFINITY) {
	    if ((rt->rt_state & (RTS_INTERFACE|RTS_INTERNAL)) == RTS_INTERFACE)
		syslog(LOG_ERR,
		    "deleting route to interface %s? (timed out?)",
		    rt->rt_ifp->int_name);
	    if (install &&
		(rt->rt_state & (RTS_INTERNAL | RTS_EXTERNAL)) == 0 &&
		ioctl(s, SIOCDELRT, (char *)&rt->rt_rt))
		    perror("SIOCDELRT");
	}
	remque(rt);
	free((char *)rt);
}

rtdeleteall(s)
	int s;
{
	register struct rthash *rh;
	register struct rt_entry *rt;
	struct rthash *base = hosthash;
	int doinghost = 1;

again:
	for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) {
		rt = rh->rt_forw;
		for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
			if (rt->rt_state & RTS_INTERFACE ||
			    rt->rt_metric >= HOPCNT_INFINITY)
				continue;
			TRACE_ACTION("DELETE", rt);
			if ((rt->rt_state & (RTS_INTERNAL|RTS_EXTERNAL)) == 0 &&
			    ioctl(s, SIOCDELRT, (char *)&rt->rt_rt))
				perror("SIOCDELRT");
		}
	}
	if (doinghost) {
		doinghost = 0;
		base = nethash;
		goto again;
	}
	exit(s);
}

/*
 * If we have an interface to the wide, wide world,
 * add an entry for an Internet default route (wildcard) to the internal
 * tables and advertise it.  This route is not added to the kernel routes,
 * but this entry prevents us from listening to other people's defaults
 * and installing them in the kernel here.
 */
rtdefault()
{
	extern struct sockaddr inet_default;

	rtadd(&inet_default, &inet_default, 1,
		RTS_CHANGED | RTS_PASSIVE | RTS_INTERNAL);
}

rtinit()
{
	register struct rthash *rh;

	for (rh = nethash; rh < &nethash[ROUTEHASHSIZ]; rh++)
		rh->rt_forw = rh->rt_back = (struct rt_entry *)rh;
	for (rh = hosthash; rh < &hosthash[ROUTEHASHSIZ]; rh++)
		rh->rt_forw = rh->rt_back = (struct rt_entry *)rh;
}
Commit	Line	Data
5ff67f98	1	/*
9c2cb70b	2	* Copyright (c) 1983, 1988 Regents of the University of California.
0eb85d71 KB	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms are permitted
b8c620d6 KB	6	* provided that the above copyright notice and this paragraph are
	7	* duplicated in all such forms and that any documentation,
	8	* advertising materials, and other materials related to such
	9	* distribution and use acknowledge that the software was developed
	10	* by the University of California, Berkeley. The name of the
	11	* University may not be used to endorse or promote products derived
	12	* from this software without specific prior written permission.
	13	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
	14	* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
	15	* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
5ff67f98 DF	16	*/
5ff67f98 DF	17
b9b7b06a	18	#ifndef lint
b8c620d6	19	static char sccsid[] = "@(#)tables.c 5.14 (Berkeley) %G%";
0eb85d71	20	#endif /* not lint */
b9b7b06a SL	21
	22	/*
	23	* Routing Table Management Daemon
	24	*/
7fe7fe74	25	#include "defs.h"
b9b7b06a SL	26	#include <sys/ioctl.h>
b9b7b06a SL	27	#include <errno.h>
9c2cb70b	28	#include <sys/syslog.h>
b9b7b06a SL	29
	30	#ifndef DEBUG
	31	#define DEBUG 0
	32	#endif
	33
	34	int install = !DEBUG; /* if 1 call kernel */
	35
	36	/*
	37	* Lookup dst in the tables for an exact match.
	38	*/
	39	struct rt_entry *
	40	rtlookup(dst)
	41	struct sockaddr *dst;
	42	{
	43	register struct rt_entry *rt;
	44	register struct rthash *rh;
d5568f13	45	register u_int hash;
b9b7b06a SL	46	struct afhash h;
	47	int doinghost = 1;
	48
17fe297f	49	if (dst->sa_family >= af_max)
b9b7b06a SL	50	return (0);
	51	(*afswitch[dst->sa_family].af_hash)(dst, &h);
	52	hash = h.afh_hosthash;
49139b80	53	rh = &hosthash[hash & ROUTEHASHMASK];
b9b7b06a SL	54	again:
	55	for (rt = rh->rt_forw; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
	56	if (rt->rt_hash != hash)
	57	continue;
	58	if (equal(&rt->rt_dst, dst))
	59	return (rt);
	60	}
	61	if (doinghost) {
	62	doinghost = 0;
	63	hash = h.afh_nethash;
49139b80	64	rh = &nethash[hash & ROUTEHASHMASK];
b9b7b06a SL	65	goto again;
	66	}
	67	return (0);
	68	}
	69
9c2cb70b MK	70	struct sockaddr wildcard; /* zero valued cookie for wildcard searches */
9c2cb70b MK	71
b9b7b06a SL	72	/*
	73	* Find a route to dst as the kernel would.
	74	*/
	75	struct rt_entry *
	76	rtfind(dst)
	77	struct sockaddr *dst;
	78	{
	79	register struct rt_entry *rt;
	80	register struct rthash *rh;
d5568f13	81	register u_int hash;
b9b7b06a SL	82	struct afhash h;
	83	int af = dst->sa_family;
	84	int doinghost = 1, (*match)();
	85
17fe297f	86	if (af >= af_max)
b9b7b06a SL	87	return (0);
	88	(*afswitch[af].af_hash)(dst, &h);
	89	hash = h.afh_hosthash;
49139b80	90	rh = &hosthash[hash & ROUTEHASHMASK];
b9b7b06a SL	91
	92	again:
	93	for (rt = rh->rt_forw; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
	94	if (rt->rt_hash != hash)
	95	continue;
	96	if (doinghost) {
	97	if (equal(&rt->rt_dst, dst))
	98	return (rt);
	99	} else {
	100	if (rt->rt_dst.sa_family == af &&
	101	(*match)(&rt->rt_dst, dst))
	102	return (rt);
	103	}
	104	}
	105	if (doinghost) {
	106	doinghost = 0;
	107	hash = h.afh_nethash;
49139b80	108	rh = &nethash[hash & ROUTEHASHMASK];
b9b7b06a SL	109	match = afswitch[af].af_netmatch;
	110	goto again;
	111	}
9c2cb70b MK	112	#ifdef notyet
	113	/*
	114	* Check for wildcard gateway, by convention network 0.
	115	*/
	116	if (dst != &wildcard) {
	117	dst = &wildcard, hash = 0;
	118	goto again;
	119	}
	120	#endif
b9b7b06a SL	121	return (0);
	122	}
	123
	124	rtadd(dst, gate, metric, state)
	125	struct sockaddr dst, gate;
	126	int metric, state;
	127	{
	128	struct afhash h;
	129	register struct rt_entry *rt;
	130	struct rthash *rh;
7892134c	131	int af = dst->sa_family, flags;
d5568f13	132	u_int hash;
b9b7b06a	133
17fe297f	134	if (af >= af_max)
b9b7b06a SL	135	return;
b9b7b06a SL	136	(*afswitch[af].af_hash)(dst, &h);
4fad5a6e MK	137	flags = (*afswitch[af].af_rtflags)(dst);
	138	/*
	139	* Subnet flag isn't visible to kernel, move to state. XXX
	140	*/
	141	if (flags & RTF_SUBNET) {
	142	state \|= RTS_SUBNET;
	143	flags &= ~RTF_SUBNET;
	144	}
b9b7b06a SL	145	if (flags & RTF_HOST) {
b9b7b06a SL	146	hash = h.afh_hosthash;
49139b80	147	rh = &hosthash[hash & ROUTEHASHMASK];
b9b7b06a SL	148	} else {
b9b7b06a SL	149	hash = h.afh_nethash;
49139b80	150	rh = &nethash[hash & ROUTEHASHMASK];
b9b7b06a SL	151	}
	152	rt = (struct rt_entry )malloc(sizeof (rt));
	153	if (rt == 0)
	154	return;
	155	rt->rt_hash = hash;
	156	rt->rt_dst = *dst;
	157	rt->rt_router = *gate;
b9b7b06a SL	158	rt->rt_timer = 0;
	159	rt->rt_flags = RTF_UP \| flags;
	160	rt->rt_state = state \| RTS_CHANGED;
4fad5a6e MK	161	rt->rt_ifp = if_ifwithdstaddr(&rt->rt_router);
	162	if (rt->rt_ifp == 0)
	163	rt->rt_ifp = if_ifwithnet(&rt->rt_router);
88709531	164	if ((state & RTS_INTERFACE) == 0)
b9b7b06a	165	rt->rt_flags \|= RTF_GATEWAY;
7892134c	166	rt->rt_metric = metric;
b9b7b06a	167	insque(rt, rh);
9c2cb70b	168	TRACE_ACTION("ADD", rt);
a8d9e287 SL	169	/*
	170	* If the ioctl fails because the gateway is unreachable
	171	* from this host, discard the entry. This should only
	172	* occur because of an incorrect entry in /etc/gateways.
	173	*/
4fad5a6e MK	174	if (install && (rt->rt_state & (RTS_INTERNAL \| RTS_EXTERNAL)) == 0 &&
4fad5a6e MK	175	ioctl(s, SIOCADDRT, (char *)&rt->rt_rt) < 0) {
7892134c	176	if (errno != EEXIST && gate->sa_family < af_max)
c766cf31 MK	177	syslog(LOG_ERR,
	178	"adding route to net/host %s through gateway %s: %m\n",
	179	(*afswitch[dst->sa_family].af_format)(dst),
	180	(*afswitch[gate->sa_family].af_format)(gate));
b9b7b06a	181	perror("SIOCADDRT");
a8d9e287	182	if (errno == ENETUNREACH) {
9c2cb70b	183	TRACE_ACTION("DELETE", rt);
a8d9e287 SL	184	remque(rt);
	185	free((char *)rt);
	186	}
	187	}
b9b7b06a SL	188	}
	189
	190	rtchange(rt, gate, metric)
	191	struct rt_entry *rt;
	192	struct sockaddr *gate;
	193	short metric;
	194	{
9c2cb70b	195	int add = 0, delete = 0;
b9b7b06a SL	196	struct rtentry oldroute;
b9b7b06a SL	197
7892134c MK	198	if ((rt->rt_state & RTS_INTERNAL) == 0) {
	199	/*
	200	* If changing to different router, we need to add
	201	* new route and delete old one if in the kernel.
	202	* If the router is the same, we need to delete
	203	* the route if has become unreachable, or re-add
	204	* it if it had been unreachable.
	205	*/
	206	if (!equal(&rt->rt_router, gate)) {
	207	add++;
	208	if (rt->rt_metric != HOPCNT_INFINITY)
	209	delete++;
	210	} else if (metric == HOPCNT_INFINITY)
eb39c032	211	delete++;
7892134c MK	212	else if (rt->rt_metric == HOPCNT_INFINITY)
7892134c MK	213	add++;
eb39c032	214	}
9c2cb70b MK	215	if (!equal(&rt->rt_router, gate)) {
	216	TRACE_ACTION("CHANGE FROM ", rt);
	217	} else if (metric != rt->rt_metric)
	218	TRACE_NEWMETRIC(rt, metric);
	219	if (delete)
	220	oldroute = rt->rt_rt;
7892134c MK	221	if ((rt->rt_state & RTS_INTERFACE) && delete) {
7892134c MK	222	rt->rt_state &= ~RTS_INTERFACE;
9c2cb70b MK	223	rt->rt_flags \|= RTF_GATEWAY;
	224	if (metric > rt->rt_metric && delete)
	225	syslog(LOG_ERR, "%s route to interface %s (timed out)",
	226	add? "changing" : "deleting",
	227	rt->rt_ifp->int_name);
b9b7b06a	228	}
7892134c MK	229	if (add) {
	230	rt->rt_router = *gate;
	231	rt->rt_ifp = if_ifwithdstaddr(&rt->rt_router);
	232	if (rt->rt_ifp == 0)
	233	rt->rt_ifp = if_ifwithnet(&rt->rt_router);
	234	}
	235	rt->rt_metric = metric;
	236	rt->rt_state \|= RTS_CHANGED;
9c2cb70b MK	237	if (add)
9c2cb70b MK	238	TRACE_ACTION("CHANGE TO ", rt);
7892134c	239	if (add && install)
b7e4f8be MK	240	if (ioctl(s, SIOCADDRT, (char *)&rt->rt_rt) < 0)
b7e4f8be MK	241	perror("SIOCADDRT");
7892134c	242	if (delete && install)
b7e4f8be MK	243	if (ioctl(s, SIOCDELRT, (char *)&oldroute) < 0)
b7e4f8be MK	244	perror("SIOCDELRT");
b9b7b06a SL	245	}
	246
	247	rtdelete(rt)
	248	struct rt_entry *rt;
	249	{
a8d9e287	250
9c2cb70b MK	251	TRACE_ACTION("DELETE", rt);
	252	if (rt->rt_metric < HOPCNT_INFINITY) {
	253	if ((rt->rt_state & (RTS_INTERFACE\|RTS_INTERNAL)) == RTS_INTERFACE)
	254	syslog(LOG_ERR,
	255	"deleting route to interface %s? (timed out?)",
	256	rt->rt_ifp->int_name);
	257	if (install &&
	258	(rt->rt_state & (RTS_INTERNAL \| RTS_EXTERNAL)) == 0 &&
	259	ioctl(s, SIOCDELRT, (char *)&rt->rt_rt))
	260	perror("SIOCDELRT");
	261	}
b9b7b06a SL	262	remque(rt);
	263	free((char *)rt);
	264	}
	265
7892134c MK	266	rtdeleteall(s)
	267	int s;
	268	{
	269	register struct rthash *rh;
	270	register struct rt_entry *rt;
	271	struct rthash *base = hosthash;
	272	int doinghost = 1;
	273
	274	again:
	275	for (rh = base; rh < &base[ROUTEHASHSIZ]; rh++) {
	276	rt = rh->rt_forw;
	277	for (; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
9c2cb70b MK	278	if (rt->rt_state & RTS_INTERFACE \|\|
9c2cb70b MK	279	rt->rt_metric >= HOPCNT_INFINITY)
7892134c	280	continue;
9c2cb70b	281	TRACE_ACTION("DELETE", rt);
7892134c MK	282	if ((rt->rt_state & (RTS_INTERNAL\|RTS_EXTERNAL)) == 0 &&
	283	ioctl(s, SIOCDELRT, (char *)&rt->rt_rt))
	284	perror("SIOCDELRT");
	285	}
	286	}
	287	if (doinghost) {
	288	doinghost = 0;
	289	base = nethash;
	290	goto again;
	291	}
9c2cb70b	292	exit(s);
7892134c MK	293	}
7892134c MK	294
ad34083f MK	295	/*
	296	* If we have an interface to the wide, wide world,
	297	* add an entry for an Internet default route (wildcard) to the internal
	298	* tables and advertise it. This route is not added to the kernel routes,
	299	* but this entry prevents us from listening to other people's defaults
	300	* and installing them in the kernel here.
	301	*/
	302	rtdefault()
	303	{
ad34083f MK	304	extern struct sockaddr inet_default;
ad34083f MK	305
09b9aef2	306	rtadd(&inet_default, &inet_default, 1,
4fad5a6e	307	RTS_CHANGED \| RTS_PASSIVE \| RTS_INTERNAL);
ad34083f MK	308	}
ad34083f MK	309
b9b7b06a SL	310	rtinit()
	311	{
	312	register struct rthash *rh;
	313
	314	for (rh = nethash; rh < &nethash[ROUTEHASHSIZ]; rh++)
	315	rh->rt_forw = rh->rt_back = (struct rt_entry *)rh;
	316	for (rh = hosthash; rh < &hosthash[ROUTEHASHSIZ]; rh++)
	317	rh->rt_forw = rh->rt_back = (struct rt_entry *)rh;
	318	}