Radix cross Linux

/*
 * Copyright (c) 1983, 1988, 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 */

/*
 * From: @(#)tables.c	5.17 (Berkeley) 6/1/90
 * From: @(#)tables.c	8.1 (Berkeley) 6/5/93
 */
char tables_rcsid[] = 
  "$Id: tables.c,v 1.13 2000/12/25 14:41:54 jr Exp $";


/*
 * Routing Table Management Daemon
 */

#include "defs.h"
#include <sys/ioctl.h>
#include <syslog.h>
#include <errno.h>
#include <search.h>

#ifndef DEBUG
#define	DEBUG	0
#endif

#define FIXLEN(s) { }

static int install = !DEBUG;		/* if 1 call kernel */
struct rthash nethash[ROUTEHASHSIZ];
struct rthash hosthash[ROUTEHASHSIZ];

/*
 * Lookup dst in the tables for an exact match.
 */
struct rt_entry *rtlookup(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(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)(struct sockaddr *,struct sockaddr *)=NULL;

	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;
	}
	return (0);
}

void rtadd(struct sockaddr *dst, struct sockaddr *gate, int metric, int state)
{
	struct afhash h;
	register struct rt_entry *rt;
	struct rthash *rh;
	int af = dst->sa_family, flags;
	u_int hash;
	char buf1[256], buf2[256];

	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
	 */
	FIXLEN(dst);
	FIXLEN(gate);
	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_dst);
	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((struct qelem *)rt, (struct qelem *)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 ((rt->rt_state & (RTS_INTERNAL | RTS_EXTERNAL)) == 0 &&
	    rtioctl(ADD, &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, buf1,
							     sizeof(buf1)),
			   (*afswitch[gate->sa_family].af_format)(gate, buf2,
							      sizeof(buf2)));
		perror("ADD ROUTE");
		if (errno == ENETUNREACH) {
			TRACE_ACTION("DELETE", rt);
			remque((struct qelem *)rt);
			free((char *)rt);
		}
	}
}

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

	FIXLEN(gate);
	FIXLEN(&(rt->rt_router));
	FIXLEN(&(rt->rt_dst));
	if (!equal(&rt->rt_router, gate)) {
		newgateway++;
		TRACE_ACTION("CHANGE FROM ", rt);
	} else if (metric != rt->rt_metric)
		TRACE_NEWMETRIC(rt, metric);
	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 (newgateway) {
			add++;
			if (rt->rt_metric != HOPCNT_INFINITY)
				delete++;
		} else if (metric == HOPCNT_INFINITY)
			delete++;
		else if (rt->rt_metric == HOPCNT_INFINITY)
			add++;
	}
	/* Linux 1.3.12 and up */
	if (kernel_version >= 0x01030b) {
		if (add && delete && rt->rt_metric == metric)
			delete = 0;
	} else {
	/* Linux 1.2.x and 1.3.7 - 1.3.11 */
		if (add && delete)
			delete = 0;
	}

	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 ? 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 (newgateway)
		TRACE_ACTION("CHANGE TO   ", rt);
	if (add && rtioctl(ADD, &rt->rt_rt) < 0)
		perror("ADD ROUTE");
	if (delete && rtioctl(DELETE, &oldroute) < 0)
		perror("DELETE ROUTE");
}

void rtdelete(struct rt_entry *rt)
{

	TRACE_ACTION("DELETE", rt);
	FIXLEN(&(rt->rt_router));
	FIXLEN(&(rt->rt_dst));
	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 ((rt->rt_state & (RTS_INTERNAL | RTS_EXTERNAL)) == 0 &&
					    rtioctl(DELETE, &rt->rt_rt) < 0)
		    perror("rtdelete");
	}
	remque((struct qelem *)rt);
	free((char *)rt);
}

void rtdeleteall(int sig)
{
	register struct rthash *rh;
	register struct rt_entry *rt;
	struct rthash *base = hosthash;
	int doinghost = 1, i;

again:
	for (i = 0; i < ROUTEHASHSIZ; i++) {
		rh = &base[i];
		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 &&
			    rtioctl(DELETE, &rt->rt_rt) < 0)
				perror("rtdeleteall");
		}
	}
	if (doinghost) {
		doinghost = 0;
		base = nethash;
		goto again;
	}
	exit(sig);
}

/*
 * 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.
 */

void rtdefault(void)
{

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

void rtinit(void)
{
	register struct rthash *rh;
	int i;

	for (i = 0; i < ROUTEHASHSIZ; i++) {
		rh = &nethash[i];
		rh->rt_forw = rh->rt_back = (struct rt_entry *)rh;
	}
	for (i = 0; i < ROUTEHASHSIZ; i++) {
		rh = &hosthash[i];
		rh->rt_forw = rh->rt_back = (struct rt_entry *)rh;
	}
}

int rtioctl(int action, struct rtuentry *ort)
{
	struct rtentry rt;
	unsigned int netmask;
	unsigned int dst;

	if (install == 0)
		return (errno = 0);

#undef rt_flags
#undef rt_ifp
#undef rt_metric
#undef rt_dst

	rt.rt_flags = (ort->rtu_flags & (RTF_UP|RTF_GATEWAY|RTF_HOST));
	rt.rt_metric = ort->rtu_metric;
	/*
	 * SIOCADDRT ioctl in linux kernels v. 2.1.15 and up will no longer
	 * add direct route to subnet/host through interface, even if the
	 * specified gateway's IP is the same as IP of that interface (BSDism).
	 * -- if this is the case, assure that no matter what kernel we use,
	 * the subnet route to directly attached network is always added
	 * to KRT as direct one.
	 */
	if (rt.rt_flags & RTF_GATEWAY) {
		rt.rt_dev = NULL;
		rt.rt_gateway = *(struct sockaddr *)&ort->rtu_router;
	} else {
		rt.rt_dev = ort->rtu_ifp->int_name;
		/*
		 * We could add a direct route to the KRT this way
		 * on whatever kernel, but kernels v. 2.1.15 and up
		 * add such route immediately as soon as the interface
		 * is labelled with IFF_UP. However, the resulting route
		 * would be added twice, since kernel distinguishes
		 * between direct route it added itself and the one
		 * added explicitly by SIOCADDRT ioctl. So instead,
		 * we safely exit with "route successfully added" sign, here.
		 */
		if (kernel_version >= 0x02010f)
			return 0;
	}
	rt.rt_dst = *(struct sockaddr *)&ort->rtu_dst;
	dst = ((struct sockaddr_in *)&rt.rt_dst)->sin_addr.s_addr;
	if (rt.rt_flags & RTF_HOST)
		netmask = 0xffffffff;
	else
		netmask = inet_maskof(dst);
	((struct sockaddr_in *)&rt.rt_genmask)->sin_family = AF_INET;
	((struct sockaddr_in *)&rt.rt_genmask)->sin_addr.s_addr = netmask;
	
	if (traceactions) {
		fprintf(ftrace, "rtioctl %s %08lx/%08lx\n",
			action == ADD ? "ADD" : "DEL",
			(unsigned long int)ntohl(dst),
			(unsigned long int)ntohl(netmask));
		fflush(ftrace);
	}

	switch (action) {

	case ADD:
		return (ioctl(sock, SIOCADDRT, (char *)&rt));

	case DELETE:
		return (ioctl(sock, SIOCDELRT, (char *)&rt));

	default:
		return (-1);
	}
}