xref: /csrg-svn/sbin/routed/inet.c (revision 27231)

/*
 * 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[] = "@(#)inet.c	5.2 (Berkeley) 04/20/86";
#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;
	}

	if (host == 0)
		return (0);	/* network */
	/*
	 * 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) == 0)
				return (RTF_SUBNET);
			else
				return (RTF_HOST);
		}
	return (RTF_HOST);
}

/*
 * Return true if a route to subnet rtsin should be sent to dst.
 * Send it only if dst is on the same logical network,
 * or the route turns out to be for the net (aka subnet 0).
 */
inet_sendsubnet(rtsin, dst)
	struct sockaddr_in *rtsin, *dst;
{
	register u_long rt = ntohl(rtsin->sin_addr.s_addr);
	register u_long d = ntohl(dst->sin_addr.s_addr);

	if (IN_CLASSA(rt)) {
		if ((rt & IN_CLASSA_HOST) == 0)
			return (1);
		return ((rt & IN_CLASSA_NET) == (d & IN_CLASSA_NET));
	} else if (IN_CLASSB(rt)) {
		if ((rt & IN_CLASSB_HOST) == 0)
			return (1);
		return ((rt & IN_CLASSB_NET) == (d & IN_CLASSB_NET));
	} else {
		if ((rt & IN_CLASSC_HOST) == 0)
			return (1);
		return ((rt & IN_CLASSC_NET) == (d & IN_CLASSC_NET));
	}
}