1 /* $OpenBSD: inet_makeaddr.c,v 1.7 2015/01/16 16:48:51 deraadt 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 <netinet/in.h>
32 #include <arpa/inet.h>
33
34 /*
35 * Formulate an Internet address from network + host. Used in
36 * building addresses stored in the ifnet structure.
37 */
38 struct in_addr
inet_makeaddr(in_addr_t net,in_addr_t host)39 inet_makeaddr(in_addr_t net, in_addr_t host)
40 {
41 in_addr_t addr;
42
43 if (net < 128)
44 addr = (net << IN_CLASSA_NSHIFT) | (host & IN_CLASSA_HOST);
45 else if (net < 65536)
46 addr = (net << IN_CLASSB_NSHIFT) | (host & IN_CLASSB_HOST);
47 else if (net < 16777216L)
48 addr = (net << IN_CLASSC_NSHIFT) | (host & IN_CLASSC_HOST);
49 else
50 addr = net | host;
51 addr = htonl(addr);
52 return (*(struct in_addr *)&addr);
53 }
54