pppd/magic.c

   1 /*
   2  * magic.c - PPP Magic Number routines.
   3  *
   4  * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  *
  18  * 3. The name "Carnegie Mellon University" must not be used to
  19  *    endorse or promote products derived from this software without
  20  *    prior written permission. For permission or any legal
  21  *    details, please contact
  22  *      Office of Technology Transfer
  23  *      Carnegie Mellon University
  24  *      5000 Forbes Avenue
  25  *      Pittsburgh, PA  15213-3890
  26  *      (412) 268-4387, fax: (412) 268-7395
  27  *      tech-transfer@andrew.cmu.edu
  28  *
  29  * 4. Redistributions of any form whatsoever must retain the following
  30  *    acknowledgment:
  31  *    "This product includes software developed by Computing Services
  32  *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
  33  *
  34  * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
  35  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  36  * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
  37  * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  38  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
  39  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  40  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  41  */
  42
  43 #define RCSID   "$Id: magic.c,v 1.11 2003/06/11 23:56:26 paulus Exp $"
  44
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <unistd.h>
  48 #include <sys/types.h>
  49 #include <sys/time.h>
  50
  51 #include "pppd.h"
  52 #include "magic.h"
  53
  54 static const char rcsid[] = RCSID;
  55
  56 extern long mrand48 __P((void));
  57 extern void srand48 __P((long));
  58
  59 /*
  60  * magic_init - Initialize the magic number generator.
  61  *
  62  * Attempts to compute a random number seed which will not repeat.
  63  * The current method uses the current hostid, current process ID
  64  * and current time, currently.
  65  */
  66 void
  67 magic_init()
  68 {
  69     long seed;
  70     struct timeval t;
  71
  72     gettimeofday(&t, NULL);
  73     seed = get_host_seed() ^ t.tv_sec ^ t.tv_usec ^ getpid();
  74     srand48(seed);
  75 }
  76
  77 /*
  78  * magic - Returns the next magic number.
  79  */
  80 u_int32_t
  81 magic()
  82 {
  83     return (u_int32_t) mrand48();
  84 }
  85
  86 /*
  87  * random_bytes - Fill a buffer with random bytes.
  88  */
  89 void
  90 random_bytes(unsigned char *buf, int len)
  91 {
  92         int i;
  93
  94         for (i = 0; i < len; ++i)
  95                 buf[i] = mrand48() >> 24;
  96 }
  97
  98 #ifdef NO_DRAND48
  99 /*
 100  * Substitute procedures for those systems which don't have
 101  * drand48 et al.
 102  */
 103
 104 double
 105 drand48()
 106 {
 107     return (double)random() / (double)0x7fffffffL; /* 2**31-1 */
 108 }
 109
 110 long
 111 mrand48()
 112 {
 113     return random();
 114 }
 115
 116 void
 117 srand48(seedval)
 118 long seedval;
 119 {
 120     srandom((int)seedval);
 121 }
 122
 123 #endif