usr/src/cmd/ipf/lib/common/fill6bits.c

   1 /*
   2  * Copyright (C) 1993-2001 by Darren Reed.
   3  *
   4  * See the IPFILTER.LICENCE file for details on licencing.
   5  *
   6  * $Id: fill6bits.c,v 1.5 2002/03/27 15:09:57 darrenr Exp $
   7  */
   8
   9 #include "ipf.h"
  10
  11
  12 void fill6bits(bits, msk)
  13 int bits;
  14 u_int *msk;
  15 {
  16         if (bits == 0) {
  17                 msk[0] = 0;
  18                 msk[1] = 0;
  19                 msk[2] = 0;
  20                 msk[3] = 0;
  21                 return;
  22         }
  23
  24         msk[0] = 0xffffffff;
  25         msk[1] = 0xffffffff;
  26         msk[2] = 0xffffffff;
  27         msk[3] = 0xffffffff;
  28
  29         if (bits == 128)
  30                 return;
  31         if (bits > 96) {
  32                 msk[3] = htonl(msk[3] << (128 - bits));
  33         } else if (bits > 64) {
  34                 msk[3] = 0;
  35                 msk[2] = htonl(msk[2] << (96 - bits));
  36         } else if (bits > 32) {
  37                 msk[3] = 0;
  38                 msk[2] = 0;
  39                 msk[1] = htonl(msk[1] << (64 - bits));
  40         } else {
  41                 msk[3] = 0;
  42                 msk[2] = 0;
  43                 msk[1] = 0;
  44                 msk[0] = htonl(msk[0] << (32 - bits));
  45         }
  46 }