first cut (incomplete) at routing

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

/*      route.c 4.3     82/03/29        */

#include "../h/param.h"
#include "../h/systm.h"
#include "../h/mbuf.h"
#include "../h/protosw.h"
#include "../h/socket.h"
#include "../h/ioctl.h"
#include "../net/in.h"
#include "../net/in_systm.h"
#include "../net/if.h"
#include "../net/af.h"
#include "../net/route.h"
#include <errno.h>

/*
* Packet routing routines.
*/

/*
* With much ado about nothing...
* route the cars that climb halfway to the stars...
*/
allocroute(ro)
       register struct route *ro;
{
       register struct rtentry *rt, *rtmin;
       register struct mbuf *m;
       register int key;
       struct afhash h;
       struct sockaddr *dst = &ro->ro_dst;
       int af = dst->sa_family, doinghost;

COUNT(ALLOCROUTE);
       if (ro->ro_rt && ro->ro_rt->rt_ifp)     /* can't happen */
               return;
       (*afswitch[af].af_hash)(dst, &h);
       m = routehash[h.afh_hosthash % RTHASHSIZ];
       key = h.afh_hostkey;
       rtmin = 0, doinghost = 1;
again:
       for (; m; m = m->m_next) {
               rt = mtod(m, struct rtentry *);
               if (rt->rt_key != key)
                       continue;
               if (doinghost) {
#define equal(a1, a2) \
       (bcmp((caddr_t)(a1), (caddr_t)(a2), sizeof(struct sockaddr)) == 0)
                       if (!equal(&rt->rt_dst, dst))
                               continue;
               } else {
                       if (rt->rt_dst.sa_family != af)
                               continue;
                       if ((*afswitch[af].af_netmatch)(&rt->rt_dst, dst) == 0)
                               continue;
               }
               if (rtmin == 0 || rt->rt_use < rtmin->rt_use)
                       rtmin = rt;
       }
       if (rtmin) {
               ro->ro_dst = rt->rt_dst;
               ro->ro_rt = rt;
               rt->rt_refcnt++;
               return (rt->rt_flags & RTF_DIRECT);
       }
       if (doinghost) {
               doinghost = 0;
               m = routehash[h.afh_nethash % RTHASHSIZ];
               key = h.afh_netkey;
               goto again;
       }
       ro->ro_rt = 0;
       return (0);
}

freeroute(rt)
       register struct rtentry *rt;
{
COUNT(FREEROUTE);
       if (rt == 0)
               panic("freeroute");
       rt->rt_refcnt--;
       /* on refcnt == 0 reclaim? notify someone? */
}

#ifdef notdef
struct rtentry *
reroute(sa)
       register struct sockaddr *sa;
{
       register struct rtentry *rt;
       register struct mbuf *m;
       register int key;
       struct afhash h;

COUNT(REROUTE);
       (*afswitch[sa->sa_family].af_hash)(sa, &h);
       m = routehash[h.afh_hosthash];
       key = h.afh_hostkey;
       for (; m; m = m->m_next) {
               rt = mtod(m, struct rtentry *);
               if (rt->rt_key != key)
                       continue;
               if (equal(&rt->rt_gateway, sa))
                       return (rt);
       }
       return (0);
}
#endif

/*
* Carry out a request to change the routing table.  Called by
* interfaces at boot time to make their ``local routes'' known
* and for ioctl's.
*/
rtrequest(req, new)
       int req;
       register struct rtentry *new;
{
       register struct rtentry *rt;
       register struct mbuf *m, **mprev;
       register int key;
       struct sockaddr *sa = &new->rt_dst;
       struct afhash h;
       int af = sa->sa_family, doinghost, s, error = 0;

COUNT(RTREQUEST);
       (*afswitch[af].af_hash)(sa, &h);
       mprev = &routehash[h.afh_hosthash % RTHASHSIZ];
       key = h.afh_hostkey;
       doinghost = 1;
       s = splimp();
again:
       for (; m = *mprev; mprev = &m->m_next) {
               rt = mtod(m, struct rtentry *);
               if (rt->rt_key != key)
                       continue;
               if (doinghost) {
                       if (!equal(&rt->rt_dst, &new->rt_dst))
                               continue;
               } else {
                       if (rt->rt_dst.sa_family != af)
                               continue;
                       if ((*afswitch[af].af_netmatch)(&rt->rt_dst, sa) == 0)
                               continue;
               }
               /* require full match on deletions */
               if (req == SIOCDELRT &&
                   !equal(&rt->rt_gateway, &new->rt_gateway))
                       continue;
               /* don't keep multiple identical entries */
               if (req == SIOCADDRT &&
                   equal(&rt->rt_gateway, &new->rt_gateway)) {
                       error = EEXIST;
                       goto bad;
               }
               break;
       }
       if (m == 0 && doinghost) {
               doinghost = 0;
               mprev = &routehash[h.afh_nethash % RTHASHSIZ];
               key = h.afh_netkey;
               goto again;
       }

       if (m == 0 && req != SIOCADDRT) {
               error = ESRCH;
               goto bad;
       }
       switch (req) {

       case SIOCDELRT:
               rt->rt_flags &= ~RTF_UP;
               if (rt->rt_refcnt > 0)  /* should we notify protocols? */
                       error = EBUSY;
               else
                       *mprev = m_free(m);
               break;

       case SIOCCHGRT:
               rt->rt_flags = new->rt_flags;
               if (rt->rt_refcnt > 0)
                       error = EBUSY;
               else if (!equal(&rt->rt_gateway, &new->rt_gateway))
                       goto newneighbor;
               break;

       case SIOCADDRT:
               m = m_getclr(M_DONTWAIT);
               if (m == 0) {
                       error = ENOBUFS;
                       break;
               }
               m->m_off = MMINOFF;
               *mprev = m;
               rt = mtod(m, struct rtentry *);
               *rt = *new;
               rt->rt_key = h.afh_nethash | h.afh_hosthash;
newneighbor:
               rt->rt_ifp = if_ifonnetof(&new->rt_gateway);
               if (rt->rt_ifp == 0)
                       rt->rt_flags &= ~RTF_UP;
               rt->rt_refcnt = 0;
               break;
       }
bad:
       splx(s);
       return (error);
}