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      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 (at) 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
    124