inetutil4.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2001 by Sun Microsystems, Inc.
* All rights reserved.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <unistd.h>
#include <netinet/in.h>
#include <libinetutil.h>
extern int getnetmaskbyaddr(const struct in_addr, struct in_addr *);
/*
* Generic internet (v4) functions.
*/
/*
* Given a host-order address, calculate client's default net mask.
* Consult netmasks database to see if net is further subnetted.
* We'll only snag the first netmask that matches our criteria.
* We return the resultant netmask in host order.
*/
void
get_netmask4(const struct in_addr *n_addrp, struct in_addr *s_addrp)
{
struct in_addr hp, tp;
/*
* First check if VLSM is in use.
*/
hp.s_addr = htonl(n_addrp->s_addr);
if (getnetmaskbyaddr(hp, &tp) == 0) {
s_addrp->s_addr = ntohl(tp.s_addr);
return;
}
/*
* Fall back on standard classed networks.
*/
if (IN_CLASSA(n_addrp->s_addr))
s_addrp->s_addr = IN_CLASSA_NET;
else if (IN_CLASSB(n_addrp->s_addr))
s_addrp->s_addr = IN_CLASSB_NET;
else
s_addrp->s_addr = IN_CLASSC_NET;
}