usr.sbin/pppd/magic.c

   1 /*
   2  * magic.c - PPP Magic Number routines.
   3  *
   4  * Copyright (c) 1989 Carnegie Mellon University.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms are permitted
   8  * provided that the above copyright notice and this paragraph are
   9  * duplicated in all such forms and that any documentation,
  10  * advertising materials, and other materials related to such
  11  * distribution and use acknowledge that the software was developed
  12  * by Carnegie Mellon University.  The name of the
  13  * University may not be used to endorse or promote products derived
  14  * from this software without specific prior written permission.
  15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  17  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  *
  19  * $FreeBSD: src/usr.sbin/pppd/magic.c,v 1.8 1999/08/28 01:19:05 peter Exp $
  20  * $DragonFly: src/usr.sbin/pppd/magic.c,v 1.4 2005/11/24 23:42:54 swildner Exp $
  21  */
  22
  23 #include <stdio.h>
  24 #include <unistd.h>
  25 #include <sys/types.h>
  26 #include <sys/time.h>
  27
  28 #include "pppd.h"
  29 #include "magic.h"
  30
  31 extern long mrand48(void);
  32 extern void srand48(long);
  33
  34 /*
  35  * magic_init - Initialize the magic number generator.
  36  *
  37  * Attempts to compute a random number seed which will not repeat.
  38  * The current method uses the current hostid, current process ID
  39  * and current time, currently.
  40  */
  41 void
  42 magic_init(void)
  43 {
  44     long seed;
  45     struct timeval t;
  46
  47     gettimeofday(&t, NULL);
  48     seed = get_host_seed() ^ t.tv_sec ^ t.tv_usec ^ getpid();
  49     srand48(seed);
  50 }
  51
  52 /*
  53  * magic - Returns the next magic number.
  54  */
  55 u_int32_t
  56 magic(void)
  57 {
  58     return (u_int32_t) mrand48();
  59 }
  60
  61 #ifdef NO_DRAND48
  62 /*
  63  * Substitute procedures for those systems which don't have
  64  * drand48 et al.
  65  */
  66
  67 double
  68 drand48(void)
  69 {
  70     return (double)random() / (double)0x7fffffffL; /* 2**31-1 */
  71 }
  72
  73 long
  74 mrand48(void)
  75 {
  76     return random();
  77 }
  78
  79 void
  80 srand48(long seedval)
  81 {
  82     srandom((int)seedval);
  83 }
  84
  85 #endif