xref: /openbsd-src/lib/libc/net/inet_makeaddr.c (revision a28daedfc357b214be5c701aa8ba8adb29a7f1c2)
1 /*	$OpenBSD: inet_makeaddr.c,v 1.6 2005/08/06 20:30:03 espie Exp $ */
2 /*
3  * Copyright (c) 1983, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. Neither the name of the University nor the names of its contributors
15  *    may be used to endorse or promote products derived from this software
16  *    without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/param.h>
32 #include <netinet/in.h>
33 #include <arpa/inet.h>
34 
35 /*
36  * Formulate an Internet address from network + host.  Used in
37  * building addresses stored in the ifnet structure.
38  */
39 struct in_addr
40 inet_makeaddr(in_addr_t net, in_addr_t host)
41 {
42 	in_addr_t addr;
43 
44 	if (net < 128)
45 		addr = (net << IN_CLASSA_NSHIFT) | (host & IN_CLASSA_HOST);
46 	else if (net < 65536)
47 		addr = (net << IN_CLASSB_NSHIFT) | (host & IN_CLASSB_HOST);
48 	else if (net < 16777216L)
49 		addr = (net << IN_CLASSC_NSHIFT) | (host & IN_CLASSC_HOST);
50 	else
51 		addr = net | host;
52 	addr = htonl(addr);
53 	return (*(struct in_addr *)&addr);
54 }
55