usr/src/lib/libsocket/inet/inet_lnaof.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1997 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 /*
  31  * University Copyright- Copyright (c) 1982, 1986, 1988
  32  * The Regents of the University of California
  33  * All Rights Reserved
  34  *
  35  * University Acknowledgment- Portions of this document are derived from
  36  * software developed by the University of California, Berkeley, and its
  37  * contributors.
  38  */
  39
  40 #pragma ident   "%Z%%M% %I%     %E% SMI"
  41
  42 #include <sys/types.h>
  43 #include <netinet/in.h>
  44
  45 /*
  46  * Return the local network address portion of an
  47  * internet address; handles class a/b/c network
  48  * number formats.
  49  */
  50 int
  51 inet_lnaof(struct in_addr in)
  52 {
  53         uint32_t i = ntohl(in.s_addr);
  54
  55         if (IN_CLASSA(i))
  56                 return ((i)&IN_CLASSA_HOST);
  57         else if (IN_CLASSB(i))
  58                 return ((i)&IN_CLASSB_HOST);
  59         else
  60                 return ((i)&IN_CLASSC_HOST);
  61 }