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 static const char rcsid[] = RCSID;
  33
  34 #ifdef NO_DRAND48
  35 long mrand48 __P((void));
  36 void srand48 __P((long));
  37 #endif
  38
  39 /*
  40  * magic_init - Initialize the magic number generator.
  41  *
  42  * Attempts to compute a random number seed which will not repeat.
  43  * The current method uses the current hostid, current process ID
  44  * and current time, currently.
  45  */
  46 void
  47 magic_init()
  48 {
  49     long seed;
  50     struct timeval t;
  51
  52     (void) gettimeofday(&t, NULL);
  53     seed = get_host_seed() ^ t.tv_sec ^ t.tv_usec ^ getpid();
  54     srand48(seed);
  55 }
  56
  57 /*
  58  * magic - Returns the next magic number.
  59  */
  60 u_int32_t
  61 magic()
  62 {
  63     return (u_int32_t) mrand48();
  64 }
  65
  66 #ifdef NO_DRAND48
  67 /*
  68  * Substitute procedures for those systems which don't have
  69  * drand48 et al.
  70  */
  71
  72 double
  73 drand48()
  74 {
  75     return (double)random() / (double)0x7fffffffL; /* 2**31-1 */
  76 }
  77
  78 long
  79 mrand48()
  80 {
  81     return random();
  82 }
  83
  84 void
  85 srand48(seedval)
  86 long seedval;
  87 {
  88     srandom((int)seedval);
  89 }
  90
  91 #endif