mirror of
https://github.com/freebsd/freebsd-src
synced 2024-09-16 06:52:27 +00:00
40 lines
603 B
C
40 lines
603 B
C
|
|
/*
|
|
* Copyright (C) 2012 by Darren Reed.
|
|
*
|
|
* See the IPFILTER.LICENCE file for details on licencing.
|
|
*
|
|
* $Id$
|
|
*/
|
|
|
|
#include "ipf.h"
|
|
|
|
|
|
/*
|
|
* count consecutive 1's in bit mask. If the mask generated by counting
|
|
* consecutive 1's is different to that passed, return -1, else return #
|
|
* of bits.
|
|
*/
|
|
int
|
|
count4bits(u_int ip)
|
|
{
|
|
int cnt = 0, i, j;
|
|
u_int ipn;
|
|
|
|
ip = ipn = ntohl(ip);
|
|
for (i = 32; i; i--, ipn *= 2)
|
|
if (ipn & 0x80000000)
|
|
cnt++;
|
|
else
|
|
break;
|
|
ipn = 0;
|
|
for (i = 32, j = cnt; i; i--, j--) {
|
|
ipn *= 2;
|
|
if (j > 0)
|
|
ipn++;
|
|
}
|
|
if (ipn == ip)
|
|
return (cnt);
|
|
return (-1);
|
|
}
|