xref: /freebsd/sbin/ipf/libipf/fill6bits.c (revision 963f5dc7a30624e95d72fb7f87b8892651164e46)
1 /*	$FreeBSD$	*/
2 
3 /*
4  * Copyright (C) 2012 by Darren Reed.
5  *
6  * See the IPFILTER.LICENCE file for details on licencing.
7  *
8  * $Id$
9  */
10 
11 #include "ipf.h"
12 
13 
14 void fill6bits(bits, msk)
15 	int bits;
16 	u_int *msk;
17 {
18 	if (bits == 0) {
19 		msk[0] = 0;
20 		msk[1] = 0;
21 		msk[2] = 0;
22 		msk[3] = 0;
23 		return;
24 	}
25 
26 	msk[0] = 0xffffffff;
27 	msk[1] = 0xffffffff;
28 	msk[2] = 0xffffffff;
29 	msk[3] = 0xffffffff;
30 
31 	if (bits == 128)
32 		return;
33 	if (bits > 96) {
34 		msk[3] = htonl(msk[3] << (128 - bits));
35 	} else if (bits > 64) {
36 		msk[3] = 0;
37 		msk[2] = htonl(msk[2] << (96 - bits));
38 	} else if (bits > 32) {
39 		msk[3] = 0;
40 		msk[2] = 0;
41 		msk[1] = htonl(msk[1] << (64 - bits));
42 	} else {
43 		msk[3] = 0;
44 		msk[2] = 0;
45 		msk[1] = 0;
46 		msk[0] = htonl(msk[0] << (32 - bits));
47 	}
48 }
49