xref: /freebsd/lib/libc/inet/inet_netof.c (revision 4f29da19bd44f0e99f021510460a81bf754c21d2)
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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static const char sccsid[] = "@(#)inet_netof.c	8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "port_before.h"
41 
42 #include <sys/param.h>
43 #include <netinet/in.h>
44 #include <arpa/inet.h>
45 
46 #include "port_after.h"
47 
48 /*
49  * Return the network number from an internet
50  * address; handles class a/b/c network #'s.
51  */
52 in_addr_t
53 inet_netof(in)
54 	struct in_addr in;
55 {
56 	in_addr_t i = ntohl(in.s_addr);
57 
58 	if (IN_CLASSA(i))
59 		return (((i)&IN_CLASSA_NET) >> IN_CLASSA_NSHIFT);
60 	else if (IN_CLASSB(i))
61 		return (((i)&IN_CLASSB_NET) >> IN_CLASSB_NSHIFT);
62 	else
63 		return (((i)&IN_CLASSC_NET) >> IN_CLASSC_NSHIFT);
64 }
65 
66 /*
67  * Weak aliases for applications that use certain private entry points,
68  * and fail to include <arpa/inet.h>.
69  */
70 #undef inet_netof
71 __weak_reference(__inet_netof, inet_netof);
72