1 /*****************************************************************************
2 * randm.h - Random number generator header file.
3 *
4 * Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
5 * Copyright (c) 1998 Global Election Systems Inc.
6 *
7 * The authors hereby grant permission to use, copy, modify, distribute,
8 * and license this software and its documentation for any purpose, provided
9 * that existing copyright notices are retained in all copies and that this
10 * notice and the following disclaimer are included verbatim in any
11 * distributions. No written agreement, license, or royalty fee is required
12 * for any of the authorized uses.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 ******************************************************************************
26 * REVISION HISTORY
27 *
28 * 03-01-01 Marc Boucher <marc@mbsi.ca>
29 *   Ported to lwIP.
30 * 98-05-29 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
31 *   Extracted from avos.
32 *****************************************************************************/
33 
34 #ifndef RANDM_H
35 #define RANDM_H
36 
37 /***********************
38 *** PUBLIC FUNCTIONS ***
39 ***********************/
40 /*
41  * Initialize the random number generator.
42  */
43 void avRandomInit(void);
44 
45 /*
46  * Churn the randomness pool on a random event.  Call this early and often
47  * on random and semi-random system events to build randomness in time for
48  * usage.  For randomly timed events, pass a null pointer and a zero length
49  * and this will use the system timer and other sources to add randomness.
50  * If new random data is available, pass a pointer to that and it will be
51  * included.
52  */
53 void avChurnRand(char *randData, u32_t randLen);
54 
55 /*
56  * Randomize our random seed value.  To be called for truely random events
57  * such as user operations and network traffic.
58  */
59 #if MD5_SUPPORT
60 #define avRandomize() avChurnRand(NULL, 0)
61 #else  /* MD5_SUPPORT */
62 void avRandomize(void);
63 #endif /* MD5_SUPPORT */
64 
65 /*
66  * Use the random pool to generate random data.  This degrades to pseudo
67  * random when used faster than randomness is supplied using churnRand().
68  * Thus it's important to make sure that the results of this are not
69  * published directly because one could predict the next result to at
70  * least some degree.  Also, it's important to get a good seed before
71  * the first use.
72  */
73 void avGenRand(char *buf, u32_t bufLen);
74 
75 /*
76  * Return a new random number.
77  */
78 u32_t avRandom(void);
79 
80 
81 #endif /* RANDM_H */
82