| /* |
| * Copyright (C) 2009 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(ip) |
| 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; |
| } |