random.h revision 11875 
1/*
2 * random.h -- A strong random number generator
3 *
4 * $Id$
5 *
6 * Version 0.92, last modified 21-Sep-95
7 *
8 * Copyright Theodore Ts'o, 1994, 1995.  All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, and the entire permission notice in its entirety,
15 *    including the disclaimer of warranties.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. The name of the author may not be used to endorse or promote
20 *    products derived from this software without specific prior
21 *    written permission.
22 *
23 * ALTERNATIVELY, this product may be distributed under the terms of
24 * the GNU Public License, in which case the provisions of the GPL are
25 * required INSTEAD OF the above restrictions.  (This clause is
26 * necessary due to a potential bad interaction between the GPL and
27 * the restrictions contained in a BSD-style copyright.)
28 *
29 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
30 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
32 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39 * OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 */
42
43/*
44 * Many kernel routines will have a use for good random numbers,
45 * for example, for truely random TCP sequence numbers, which prevent
46 * certain forms of TCP spoofing attacks.
47 *
48 */
49
50#ifndef _MACHINE_RANDOM_H_
51#define _MACHINE_RANDOM_H_ 1
52
53#include <sys/ioctl.h>
54
55#define	MEM_SETIRQ	_IOW('r', 1, int)	/* set interrupt */
56#define	MEM_CLEARIRQ	_IOW('r', 2, int)	/* clear interrupt */
57#define	MEM_RETURNIRQ	_IOR('r', 3, int)	/* return interrupt */
58
59/* Interrupts to be used in the randomising process */
60
61extern u_int16_t interrupt_allowed;
62
63/* Exported functions */
64
65void rand_initialize(void);
66void add_keyboard_randomness(u_char scancode);
67
68void get_random_bytes(void *buf, u_int nbytes);
69u_int read_random(char *buf, u_int size);
70u_int read_random_unlimited(char *buf, u_int size);
71
72#endif
73