xref: /freebsd/lib/libc/inet/inet_netof.c (revision a0b9e2e854027e6ff61fb075a1309dbc71c42b54)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #if defined(LIBC_SCCS) && !defined(lint)
33 static const char sccsid[] = "@(#)inet_netof.c	8.1 (Berkeley) 6/4/93";
34 #endif /* LIBC_SCCS and not lint */
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include "port_before.h"
39 
40 #include <sys/param.h>
41 #include <netinet/in.h>
42 #include <arpa/inet.h>
43 
44 #include "port_after.h"
45 
46 /*%
47  * Return the network number from an internet
48  * address; handles class a/b/c network #'s.
49  */
50 in_addr_t
51 inet_netof(struct in_addr in)
52 {
53 	in_addr_t i = ntohl(in.s_addr);
54 
55 	if (IN_CLASSA(i))
56 		return (((i)&IN_CLASSA_NET) >> IN_CLASSA_NSHIFT);
57 	else if (IN_CLASSB(i))
58 		return (((i)&IN_CLASSB_NET) >> IN_CLASSB_NSHIFT);
59 	else
60 		return (((i)&IN_CLASSC_NET) >> IN_CLASSC_NSHIFT);
61 }
62 
63 /*
64  * Weak aliases for applications that use certain private entry points,
65  * and fail to include <arpa/inet.h>.
66  */
67 #undef inet_netof
68 __weak_reference(__inet_netof, inet_netof);
69 
70 /*! \file */
71