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

/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/

#ifndef lint
static char sccsid[] = "@(#)tables.c    5.9 (Berkeley) %G%";
#endif not lint

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

/*
* 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;
       }
       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, ifmetric;
       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 (rt->rt_ifp)
               ifmetric = rt->rt_ifp->int_metric;
       else
               ifmetric = 0;
       if ((state & RTS_INTERFACE) == 0)
               rt->rt_flags |= RTF_GATEWAY;
       /*
        * Set rt_ifmetric to the amount by which we
        * increment the route when sending it to others.
        */
       if (state & RTS_INTERFACE) {
               rt->rt_metric = 0;
               rt->rt_ifmetric = metric + 1;
       } else {
               rt->rt_metric = metric;
               rt->rt_ifmetric = ifmetric + 1;
       }
       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 &&
                   dst->sa_family < af_max && 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 doioctl = 0, metricchanged = 0, delete = 0;
       struct rtentry oldroute;

       if (!equal(&rt->rt_router, gate) && (rt->rt_state & RTS_INTERNAL) == 0)
               doioctl++;
       if (metric != rt->rt_metric) {
               metricchanged++;
               if (metric == HOPCNT_INFINITY)
                       delete++;
       }
       if (doioctl || metricchanged) {
               TRACE_ACTION(CHANGE FROM, rt);
               if ((rt->rt_state & RTS_INTERFACE) &&
                   metric > rt->rt_ifp->int_metric) {
                       rt->rt_state &= ~RTS_INTERFACE;
                       rt->rt_flags |= RTF_GATEWAY;
                       syslog(LOG_ERR,
                               "changing route from interface %s (timed out)",
                               rt->rt_ifp->int_name);
               }
               if (doioctl || delete)
                       oldroute = rt->rt_rt;
               if (doioctl) {
                       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;
               TRACE_ACTION(CHANGE TO, rt);
       }
       if (doioctl && install)
               if (ioctl(s, SIOCADDRT, (char *)&rt->rt_rt) < 0)
                       perror("SIOCADDRT");
       if ((doioctl || delete) && install)
               if (ioctl(s, SIOCDELRT, (char *)&oldroute) < 0)
                       perror("SIOCDELRT");
}

rtdelete(rt)
       struct rt_entry *rt;
{

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

/*
* 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, 0,
               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;
}