usr/src/cmd/cmd-inet/usr.bin/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
  20 #pragma ident   "%Z%%M% %I%     %E% SMI"
  21 #define RCSID   "$Id: magic.c,v 1.9 1999/08/13 06:46:15 paulus Exp $"
  22
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <unistd.h>
  26 #include <sys/types.h>
  27 #include <sys/time.h>
  28
  29 #include "pppd.h"
  30 #include "magic.h"
  31
  32 #if !defined(lint) && !defined(_lint)
  33 static const char rcsid[] = RCSID;
  34 #endif
  35
  36 #ifdef NO_DRAND48
  37 long mrand48 __P((void));
  38 void srand48 __P((long));
  39 #endif
  40
  41 /*
  42  * magic_init - Initialize the magic number generator.
  43  *
  44  * Attempts to compute a random number seed which will not repeat.
  45  * The current method uses the current hostid, current process ID
  46  * and current time, currently.
  47  */
  48 void
  49 magic_init()
  50 {
  51     long seed;
  52     struct timeval t;
  53
  54     (void) gettimeofday(&t, NULL);
  55     seed = get_host_seed() ^ t.tv_sec ^ t.tv_usec ^ getpid();
  56     srand48(seed);
  57 }
  58
  59 /*
  60  * magic - Returns the next magic number.
  61  */
  62 u_int32_t
  63 magic()
  64 {
  65     return (u_int32_t) mrand48();
  66 }
  67
  68 #ifdef NO_DRAND48
  69 /*
  70  * Substitute procedures for those systems which don't have
  71  * drand48 et al.
  72  */
  73
  74 double
  75 drand48()
  76 {
  77     return (double)random() / (double)0x7fffffffL; /* 2**31-1 */
  78 }
  79
  80 long
  81 mrand48()
  82 {
  83     return random();
  84 }
  85
  86 void
  87 srand48(seedval)
  88 long seedval;
  89 {
  90     srandom((int)seedval);
  91 }
  92
  93 #endif