src/libfreeswan/libfreeswan/subnetof.c

   1 /*
   2  * minor network-address manipulation utilities
   3  * Copyright (C) 1998, 1999  Henry Spencer.
   4  *
   5  * This library is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU Library General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/lgpl.txt>.
   9  *
  10  * This library is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
  13  * License for more details.
  14  *
  15  * RCSID $Id: subnetof.c,v 1.1 2004/03/15 20:35:26 as Exp $
  16  */
  17 #include "internal.h"
  18 #include "freeswan.h"
  19
  20 /*
  21  - subnetof - given address and mask, return subnet part
  22  */
  23 struct in_addr
  24 subnetof(addr, mask)
  25 struct in_addr addr;
  26 struct in_addr mask;
  27 {
  28         struct in_addr result;
  29
  30         result.s_addr = addr.s_addr & mask.s_addr;
  31         return result;
  32 }
  33
  34 /*
  35  - hostof - given address and mask, return host part
  36  */
  37 struct in_addr
  38 hostof(addr, mask)
  39 struct in_addr addr;
  40 struct in_addr mask;
  41 {
  42         struct in_addr result;
  43
  44         result.s_addr = addr.s_addr & ~mask.s_addr;
  45         return result;
  46 }
  47
  48 /*
  49  - broadcastof - given (network) address and mask, return broadcast address
  50  */
  51 struct in_addr
  52 broadcastof(addr, mask)
  53 struct in_addr addr;
  54 struct in_addr mask;
  55 {
  56         struct in_addr result;
  57
  58         result.s_addr = addr.s_addr | ~mask.s_addr;
  59         return result;
  60 }