BSD 4_2 release

[unix-history] / usr / src / sys / net / route.c

/*      route.c 6.2     83/10/20        */

#include "../h/param.h"
#include "../h/systm.h"
#include "../h/mbuf.h"
#include "../h/protosw.h"
#include "../h/socket.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/ioctl.h"
#include "../h/errno.h"

#include "../net/if.h"
#include "../net/af.h"
#include "../net/route.h"

int     rttrash;                /* routes not in table but not freed */
struct  sockaddr wildcard;      /* zero valued cookie for wildcard searches */

/*
* Packet routing routines.
*/
rtalloc(ro)
       register struct route *ro;
{
       register struct rtentry *rt;
       register struct mbuf *m;
       register u_long hash;
       struct sockaddr *dst = &ro->ro_dst;
       int (*match)(), doinghost;
       struct afhash h;
       u_int af = dst->sa_family;
       struct rtentry *rtmin;
       struct mbuf **table;

       if (ro->ro_rt && ro->ro_rt->rt_ifp)                     /* XXX */
               return;
       if (af >= AF_MAX)
               return;
       (*afswitch[af].af_hash)(dst, &h);
       rtmin = 0;
       match = afswitch[af].af_netmatch;
       hash = h.afh_hosthash, table = rthost, doinghost = 1;
again:
       for (m = table[hash % RTHASHSIZ]; m; m = m->m_next) {
               rt = mtod(m, struct rtentry *);
               if (rt->rt_hash != hash)
                       continue;
               if ((rt->rt_flags & RTF_UP) == 0 ||
                   (rt->rt_ifp->if_flags & IFF_UP) == 0)
                       continue;
               if (doinghost) {
                       if (bcmp((caddr_t)&rt->rt_dst, (caddr_t)dst,
                           sizeof (*dst)))
                               continue;
               } else {
                       if (rt->rt_dst.sa_family != af ||
                           !(*match)(&rt->rt_dst, dst))
                               continue;
               }
               if (rtmin == 0 || rt->rt_use < rtmin->rt_use)
                       rtmin = rt;
       }
       if (rtmin == 0 && doinghost) {
               doinghost = 0;
               hash = h.afh_nethash, table = rtnet;
               goto again;
       }
       /*
        * Check for wildcard gateway, by convention network 0.
        */
       if (rtmin == 0 && dst != &wildcard) {
               dst = &wildcard, hash = 0;
               goto again;
       }
       ro->ro_rt = rtmin;
       if (rtmin == 0) {
               rtstat.rts_unreach++;
               return;
       }
       rtmin->rt_refcnt++;
       if (dst == &wildcard)
               rtstat.rts_wildcard++;
}

rtfree(rt)
       register struct rtentry *rt;
{

       if (rt == 0)
               panic("rtfree");
       rt->rt_refcnt--;
       if (rt->rt_refcnt == 0 && (rt->rt_flags&RTF_UP) == 0) {
               rttrash--;
               (void) m_free(dtom(rt));
       }
}

/*
* 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 splnet or higher
*
* Should notify all parties with a reference to
* the route that it's changed (so, for instance,
* current round trip time estimates could be flushed),
* but we have no back pointers at the moment.
*/
rtredirect(dst, gateway)
       struct sockaddr *dst, *gateway;
{
       struct route ro;
       register struct rtentry *rt;

       /* verify the gateway is directly reachable */
       if (if_ifwithnet(gateway) == 0) {
               rtstat.rts_badredirect++;
               return;
       }
       ro.ro_dst = *dst;
       ro.ro_rt = 0;
       rtalloc(&ro);
       rt = ro.ro_rt;
       /*
        * Create a new entry if we just got back a wildcard entry
        * or the the lookup failed.  This is necessary for hosts
        * which use routing redirects generated by smart gateways
        * to dynamically build the routing tables.
        */
       if (rt &&
           (*afswitch[dst->sa_family].af_netmatch)(&wildcard, &rt->rt_dst)) {
               rtfree(rt);
               rt = 0;
       }
       if (rt == 0) {
               rtinit(dst, gateway, RTF_GATEWAY);
               rtstat.rts_dynamic++;
               return;
       }
       /*
        * Don't listen to the redirect if it's
        * for a route to an interface. 
        */
       if (rt->rt_flags & RTF_GATEWAY) {
               /*
                * Smash the current notion of the gateway to
                * this destination.  This is probably not right,
                * as it's conceivable a flurry of redirects could
                * cause the gateway value to fluctuate wildly during
                * dynamic routing reconfiguration.
                */
               rt->rt_gateway = *gateway;
               rtfree(rt);
               rtstat.rts_newgateway++;
               return;
       }
}

/*
* Routing table ioctl interface.
*/
rtioctl(cmd, data)
       int cmd;
       caddr_t data;
{

       if (cmd != SIOCADDRT && cmd != SIOCDELRT)
               return (EINVAL);
       if (!suser())
               return (u.u_error);
       return (rtrequest(cmd, (struct rtentry *)data));
}

/*
* Carry out a request to change the routing table.  Called by
* interfaces at boot time to make their ``local routes'' known,
* for ioctl's, and as the result of routing redirects.
*/
rtrequest(req, entry)
       int req;
       register struct rtentry *entry;
{
       register struct mbuf *m, **mprev;
       register struct rtentry *rt;
       struct afhash h;
       int s, error = 0, (*match)();
       u_int af;
       u_long hash;
       struct ifnet *ifp;

       af = entry->rt_dst.sa_family;
       if (af >= AF_MAX)
               return (EAFNOSUPPORT);
       (*afswitch[af].af_hash)(&entry->rt_dst, &h);
       if (entry->rt_flags & RTF_HOST) {
               hash = h.afh_hosthash;
               mprev = &rthost[hash % RTHASHSIZ];
       } else {
               hash = h.afh_nethash;
               mprev = &rtnet[hash % RTHASHSIZ];
       }
       match = afswitch[af].af_netmatch;
       s = splimp();
       for (; m = *mprev; mprev = &m->m_next) {
               rt = mtod(m, struct rtentry *);
               if (rt->rt_hash != hash)
                       continue;
               if (entry->rt_flags & RTF_HOST) {
#define equal(a1, a2) \
       (bcmp((caddr_t)(a1), (caddr_t)(a2), sizeof (struct sockaddr)) == 0)
                       if (!equal(&rt->rt_dst, &entry->rt_dst))
                               continue;
               } else {
                       if (rt->rt_dst.sa_family != entry->rt_dst.sa_family ||
                           (*match)(&rt->rt_dst, &entry->rt_dst) == 0)
                               continue;
               }
               if (equal(&rt->rt_gateway, &entry->rt_gateway))
                       break;
       }
       switch (req) {

       case SIOCDELRT:
               if (m == 0) {
                       error = ESRCH;
                       goto bad;
               }
               *mprev = m->m_next;
               if (rt->rt_refcnt > 0) {
                       rt->rt_flags &= ~RTF_UP;
                       rttrash++;
                       m->m_next = 0;
               } else
                       (void) m_free(m);
               break;

       case SIOCADDRT:
               if (m) {
                       error = EEXIST;
                       goto bad;
               }
               ifp = if_ifwithaddr(&entry->rt_gateway);
               if (ifp == 0) {
                       ifp = if_ifwithnet(&entry->rt_gateway);
                       if (ifp == 0) {
                               error = ENETUNREACH;
                               goto bad;
                       }
               }
               m = m_get(M_DONTWAIT, MT_RTABLE);
               if (m == 0) {
                       error = ENOBUFS;
                       goto bad;
               }
               *mprev = m;
               m->m_off = MMINOFF;
               m->m_len = sizeof (struct rtentry);
               rt = mtod(m, struct rtentry *);
               rt->rt_hash = hash;
               rt->rt_dst = entry->rt_dst;
               rt->rt_gateway = entry->rt_gateway;
               rt->rt_flags =
                   RTF_UP | (entry->rt_flags & (RTF_HOST|RTF_GATEWAY));
               rt->rt_refcnt = 0;
               rt->rt_use = 0;
               rt->rt_ifp = ifp;
               break;
       }
bad:
       splx(s);
       return (error);
}

/*
* Set up a routing table entry, normally
* for an interface.
*/
rtinit(dst, gateway, flags)
       struct sockaddr *dst, *gateway;
       int flags;
{
       struct rtentry route;
       int cmd;

       if (flags == -1) {
               cmd = (int)SIOCDELRT;
               flags = 0;
       } else {
               cmd = (int)SIOCADDRT;
       }
       bzero((caddr_t)&route, sizeof (route));
       route.rt_dst = *dst;
       route.rt_gateway = *gateway;
       route.rt_flags = flags;
       (void) rtrequest(cmd, &route);
}