new subnets

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

#ifndef lint
static char *sccsid[] = "@(#)inet.c     4.3 (Berkeley) %G%";
#endif
/*
* Temporarily, copy these routines from the kernel,
* as we need to know about subnets.
*/
#include "defs.h"

extern struct interface *ifnet;

/*
* Formulate an Internet address from network + host.
*/
struct in_addr
inet_makeaddr(net, host)
       u_long net, host;
{
       register struct interface *ifp;
       register u_long mask;
       u_long addr;

       if (IN_CLASSA(net))
               mask = IN_CLASSA_HOST;
       else if (IN_CLASSB(net))
               mask = IN_CLASSB_HOST;
       else
               mask = IN_CLASSC_HOST;
       for (ifp = ifnet; ifp; ifp = ifp->int_next)
               if ((ifp->int_netmask & net) == ifp->int_net) {
                       mask = ~ifp->int_subnetmask;
                       break;
               }
       addr = net | (host & mask);
       addr = htonl(addr);
       return (*(struct in_addr *)&addr);
}

/*
* Return the network number from an internet address.
*/
inet_netof(in)
       struct in_addr in;
{
       register u_long i = ntohl(in.s_addr);
       register u_long net;
       register struct interface *ifp;

       if (IN_CLASSA(i))
               net = i & IN_CLASSA_NET;
       else if (IN_CLASSB(i))
               net = i & IN_CLASSB_NET;
       else
               net = i & IN_CLASSC_NET;

       /*
        * Check whether network is a subnet;
        * if so, return subnet number.
        */
       for (ifp = ifnet; ifp; ifp = ifp->int_next)
               if ((ifp->int_netmask & net) == ifp->int_net)
                       return (i & ifp->int_subnetmask);
       return (net);
}

/*
* Return the host portion of an internet address.
*/
inet_lnaof(in)
       struct in_addr in;
{
       register u_long i = ntohl(in.s_addr);
       register u_long net, host;
       register struct interface *ifp;

       if (IN_CLASSA(i)) {
               net = i & IN_CLASSA_NET;
               host = i & IN_CLASSA_HOST;
       } else if (IN_CLASSB(i)) {
               net = i & IN_CLASSB_NET;
               host = i & IN_CLASSB_HOST;
       } else {
               net = i & IN_CLASSC_NET;
               host = i & IN_CLASSC_HOST;
       }

       /*
        * Check whether network is a subnet;
        * if so, use the modified interpretation of `host'.
        */
       for (ifp = ifnet; ifp; ifp = ifp->int_next)
               if ((ifp->int_netmask & net) == ifp->int_net)
                       return (host &~ ifp->int_subnetmask);
       return (host);
}