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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@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
magic_init()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
magic()81 magic()
82 {
83     return (u_int32_t) mrand48();
84 }
85 
86 /*
87  * random_bytes - Fill a buffer with random bytes.
88  */
89 void
random_bytes(unsigned char * buf,int len)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
drand48()105 drand48()
106 {
107     return (double)random() / (double)0x7fffffffL; /* 2**31-1 */
108 }
109 
110 long
mrand48()111 mrand48()
112 {
113     return random();
114 }
115 
116 void
srand48(seedval)117 srand48(seedval)
118 long seedval;
119 {
120     srandom((int)seedval);
121 }
122 
123 #endif
124