routed/inet.c

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static char sccsid[] = "@(#)inet.c      5.7 (Berkeley) 6/18/88";
#endif /* not lint */

/*
 * 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);
}

/*
 * Return RTF_HOST if the address is
 * for an Internet host, RTF_SUBNET for a subnet,
 * 0 for a network.
 */
inet_rtflags(sin)
        struct sockaddr_in *sin;
{
        register u_long i = ntohl(sin->sin_addr.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 this network is subnetted;
         * if so, check whether this is a subnet or a host.
         */
        for (ifp = ifnet; ifp; ifp = ifp->int_next)
                if (net == ifp->int_net) {
                        if (host &~ ifp->int_subnetmask)
                                return (RTF_HOST);
                        else if (ifp->int_subnetmask != ifp->int_netmask)
                                return (RTF_SUBNET);
                        else
                                return (0);             /* network */
                }
        if (host == 0)
                return (0);     /* network */
        else
                return (RTF_HOST);
}

/*
 * Return true if a route to subnet/host of route rt should be sent to dst.
 * Send it only if dst is on the same logical network if not "internal",
 * otherwise only if the route is the "internal" route for the logical net.
 */
inet_sendroute(rt, dst)
        struct rt_entry *rt;
        struct sockaddr_in *dst;
{
        register u_long r =
            ntohl(((struct sockaddr_in *)&rt->rt_dst)->sin_addr.s_addr);
        register u_long d = ntohl(dst->sin_addr.s_addr);

        if (IN_CLASSA(r)) {
                if ((r & IN_CLASSA_NET) == (d & IN_CLASSA_NET)) {
                        if ((r & IN_CLASSA_HOST) == 0)
                                return ((rt->rt_state & RTS_INTERNAL) == 0);
                        return (1);
                }
                if (r & IN_CLASSA_HOST)
                        return (0);
                return ((rt->rt_state & RTS_INTERNAL) != 0);
        } else if (IN_CLASSB(r)) {
                if ((r & IN_CLASSB_NET) == (d & IN_CLASSB_NET)) {
                        if ((r & IN_CLASSB_HOST) == 0)
                                return ((rt->rt_state & RTS_INTERNAL) == 0);
                        return (1);
                }
                if (r & IN_CLASSB_HOST)
                        return (0);
                return ((rt->rt_state & RTS_INTERNAL) != 0);
        } else {
                if ((r & IN_CLASSC_NET) == (d & IN_CLASSC_NET)) {
                        if ((r & IN_CLASSC_HOST) == 0)
                                return ((rt->rt_state & RTS_INTERNAL) == 0);
                        return (1);
                }
                if (r & IN_CLASSC_HOST)
                        return (0);
                return ((rt->rt_state & RTS_INTERNAL) != 0);
        }
}