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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * include/linux/random.h
3 *
4 * Include file for the random number generator.
5 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006#ifndef _LINUX_RANDOM_H
7#define _LINUX_RANDOM_H
8
David Howells607ca462012-10-13 10:46:48 +01009#include <uapi/linux/random.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010
Linus Torvaldsa2080a62012-07-04 11:16:01 -040011extern void add_device_randomness(const void *, unsigned int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070012extern void add_input_randomness(unsigned int type, unsigned int code,
13 unsigned int value);
Theodore Ts'o775f4b22012-07-02 07:52:16 -040014extern void add_interrupt_randomness(int irq, int irq_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
16extern void get_random_bytes(void *buf, int nbytes);
Theodore Ts'oc2557a32012-07-05 10:35:23 -040017extern void get_random_bytes_arch(void *buf, int nbytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -070018void generate_random_uuid(unsigned char uuid_out[16]);
Theodore Ts'o47d06e52013-09-10 10:52:35 -040019extern int random_int_secret_init(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#ifndef MODULE
Arjan van de Ven54047322007-02-12 00:55:28 -080022extern const struct file_operations random_fops, urandom_fops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#endif
24
25unsigned int get_random_int(void);
26unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
27
Akinobu Mita496f2f92012-12-17 16:04:23 -080028u32 prandom_u32(void);
Akinobu Mita6582c662012-12-17 16:04:25 -080029void prandom_bytes(void *buf, int nbytes);
Akinobu Mita496f2f92012-12-17 16:04:23 -080030void prandom_seed(u32 seed);
Hannes Frederic Sowa4af712e2013-11-11 12:20:34 +010031void prandom_reseed_late(void);
Stephen Hemmingeraaa248f2006-10-17 00:09:42 -070032
Daniel Borkmann38e9efc2013-11-11 12:20:35 +010033struct rnd_state {
Daniel Borkmanna98814c2013-11-11 12:20:36 +010034 __u32 s1, s2, s3, s4;
Daniel Borkmann38e9efc2013-11-11 12:20:35 +010035};
36
Daniel Borkmanna98814c2013-11-11 12:20:36 +010037u32 prandom_u32_state(struct rnd_state *state);
Akinobu Mita6582c662012-12-17 16:04:25 -080038void prandom_bytes_state(struct rnd_state *state, void *buf, int nbytes);
Joe Eykholt59601642010-05-26 14:44:13 -070039
Daniel Borkmannf337db62014-01-22 02:29:39 +010040/**
41 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
42 * @ep_ro: right open interval endpoint
43 *
44 * Returns a pseudo-random number that is in interval [0, ep_ro). Note
45 * that the result depends on PRNG being well distributed in [0, ~0U]
46 * u32 space. Here we use maximally equidistributed combined Tausworthe
47 * generator, that is, prandom_u32(). This is useful when requesting a
48 * random index of an array containing ep_ro elements, for example.
49 *
50 * Returns: pseudo-random number in interval [0, ep_ro)
51 */
52static inline u32 prandom_u32_max(u32 ep_ro)
53{
54 return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
55}
56
Joe Eykholt59601642010-05-26 14:44:13 -070057/*
58 * Handle minimum values for seeds
59 */
60static inline u32 __seed(u32 x, u32 m)
61{
62 return (x < m) ? x + m : x;
63}
64
65/**
Akinobu Mita496f2f92012-12-17 16:04:23 -080066 * prandom_seed_state - set seed for prandom_u32_state().
Joe Eykholt59601642010-05-26 14:44:13 -070067 * @state: pointer to state structure to receive the seed.
68 * @seed: arbitrary 64-bit value to use as a seed.
69 */
Akinobu Mita496f2f92012-12-17 16:04:23 -080070static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
Joe Eykholt59601642010-05-26 14:44:13 -070071{
72 u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
73
Daniel Borkmanna98814c2013-11-11 12:20:36 +010074 state->s1 = __seed(i, 2U);
75 state->s2 = __seed(i, 8U);
76 state->s3 = __seed(i, 16U);
77 state->s4 = __seed(i, 128U);
Joe Eykholt59601642010-05-26 14:44:13 -070078}
79
H. Peter Anvin63d77172011-07-31 13:54:50 -070080#ifdef CONFIG_ARCH_RANDOM
81# include <asm/archrandom.h>
82#else
83static inline int arch_get_random_long(unsigned long *v)
84{
85 return 0;
86}
87static inline int arch_get_random_int(unsigned int *v)
88{
89 return 0;
90}
H. Peter Anvin7b878d42014-03-17 16:36:30 -070091static inline int arch_has_random(void)
92{
93 return 0;
94}
H. Peter Anvind20f78d2014-03-17 16:36:27 -070095static inline int arch_get_random_seed_long(unsigned long *v)
96{
97 return 0;
98}
99static inline int arch_get_random_seed_int(unsigned int *v)
100{
101 return 0;
102}
H. Peter Anvin7b878d42014-03-17 16:36:30 -0700103static inline int arch_has_random_seed(void)
104{
105 return 0;
106}
H. Peter Anvin63d77172011-07-31 13:54:50 -0700107#endif
108
Tom Herbert055dc212013-01-22 09:49:50 +0000109/* Pseudo random number generator from numerical recipes. */
110static inline u32 next_pseudo_random32(u32 seed)
111{
112 return seed * 1664525 + 1013904223;
113}
114
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115#endif /* _LINUX_RANDOM_H */