xref: /freebsd/lib/libc/inet/inet_netof.c (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
1 /*
2  * Copyright (c) 1983, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static const char sccsid[] = "@(#)inet_netof.c	8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include "port_before.h"
37 
38 #include <sys/param.h>
39 #include <netinet/in.h>
40 #include <arpa/inet.h>
41 
42 #include "port_after.h"
43 
44 /*%
45  * Return the network number from an internet
46  * address; handles class a/b/c network #'s.
47  */
48 in_addr_t
49 inet_netof(in)
50 	struct in_addr in;
51 {
52 	in_addr_t i = ntohl(in.s_addr);
53 
54 	if (IN_CLASSA(i))
55 		return (((i)&IN_CLASSA_NET) >> IN_CLASSA_NSHIFT);
56 	else if (IN_CLASSB(i))
57 		return (((i)&IN_CLASSB_NET) >> IN_CLASSB_NSHIFT);
58 	else
59 		return (((i)&IN_CLASSC_NET) >> IN_CLASSC_NSHIFT);
60 }
61 
62 /*
63  * Weak aliases for applications that use certain private entry points,
64  * and fail to include <arpa/inet.h>.
65  */
66 #undef inet_netof
67 __weak_reference(__inet_netof, inet_netof);
68 
69 /*! \file */
70