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, 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.
 */

#ifndef lint
static char sccsid[] = "@(#)tables.c    5.17 (Berkeley) 6/1/90";
#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

#ifdef RTM_ADD
#define FIXLEN(s) {if ((s)->sa_len == 0) (s)->sa_len = sizeof *(s);}
#else
#define FIXLEN(s) { }
#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
         */
        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);
                /*
                 * seems like we can't figure out the interface for the
                 * IP address of the local side of a point to point
                 * connection, we just don't add that entry in the
                 * table. (it seems to already be there anyway)
                 */
                if (rt->rt_ifp == 0) {
                        syslog(LOG_DEBUG,
                               "rtadd: can't get interface for %s",
                               (*afswitch[dst->sa_family].af_format)(dst));
                        return;
                }
        }
        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, newgateway = 0;
        struct rtentry 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++;
        }
        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);
                        /*
                         * seems like we can't figure out the interface for the
                         * IP address of the local side of a point to point
                         * connection, we just don't add that entry in the
                         * table. (it seems to already be there anyway)
                         */
                        if (rt->rt_ifp == 0) {
                                struct sockaddr *dst = &(rt->rt_dst);
                                syslog(LOG_DEBUG,
                                       "rtchange: can't get interface for %s",
                                       (*afswitch[dst->sa_family].af_format)(dst));
                                return;
                        }
                }
        }
        rt->rt_metric = metric;
        rt->rt_state |= RTS_CHANGED;
        if (newgateway)
                TRACE_ACTION("CHANGE TO   ", rt);
#ifndef RTM_ADD
        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");
#else
        if (delete && install)
                if (ioctl(s, SIOCDELRT, (char *)&oldroute) < 0)
                        perror("SIOCDELRT");
        if (add && install) {
                if (ioctl(s, SIOCADDRT, (char *)&rt->rt_rt) < 0)
                        perror("SIOCADDRT");
        }
#endif
}

rtdelete(rt)
        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 (install &&
                (rt->rt_state & (RTS_INTERNAL | RTS_EXTERNAL)) == 0 &&
                ioctl(s, SIOCDELRT, (char *)&rt->rt_rt))
                    perror("SIOCDELRT");
        }
        remque(rt);
        free((char *)rt);
}

rtdeleteall(sig)
        int sig;
{
        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(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.
 */
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;
}


/* ffrom /sys/i386/i386/machdep.c */
/*
 * insert an element into a queue
 */
insque(element, head)
        register struct rthash *element, *head;
{
        element->rt_forw = head->rt_forw;
        head->rt_forw = (struct rt_entry *)element;
        element->rt_back = (struct rt_entry *)head;
        ((struct rthash *)(element->rt_forw))->rt_back=(struct rt_entry *)element;
}

/*
 * remove an element from a queue
 */
remque(element)
        register struct rthash *element;
{
        ((struct rthash *)(element->rt_forw))->rt_back = element->rt_back;
        ((struct rthash *)(element->rt_back))->rt_forw = element->rt_forw;
        element->rt_back = (struct rt_entry *)0;
}