1/*
2 * include/linux/random.h
3 *
4 * Include file for the random number generator.
5 */
6#ifndef _LINUX_RANDOM_H
7#define _LINUX_RANDOM_H
8
9#include <uapi/linux/random.h>
10
11extern void add_device_randomness(const void *, unsigned int);
12extern void add_input_randomness(unsigned int type, unsigned int code,
13				 unsigned int value);
14extern void add_interrupt_randomness(int irq, int irq_flags);
15
16extern void get_random_bytes(void *buf, int nbytes);
17extern void get_random_bytes_arch(void *buf, int nbytes);
18void generate_random_uuid(unsigned char uuid_out[16]);
19extern int random_int_secret_init(void);
20
21#ifndef MODULE
22extern const struct file_operations random_fops, urandom_fops;
23#endif
24
25unsigned int get_random_int(void);
26unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
27
28u32 prandom_u32(void);
29void prandom_bytes(void *buf, size_t nbytes);
30void prandom_seed(u32 seed);
31void prandom_reseed_late(void);
32
33struct rnd_state {
34	__u32 s1, s2, s3, s4;
35};
36
37u32 prandom_u32_state(struct rnd_state *state);
38void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
39
40/**
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
57/*
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/**
66 * prandom_seed_state - set seed for prandom_u32_state().
67 * @state: pointer to state structure to receive the seed.
68 * @seed: arbitrary 64-bit value to use as a seed.
69 */
70static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
71{
72	u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
73
74	state->s1 = __seed(i,   2U);
75	state->s2 = __seed(i,   8U);
76	state->s3 = __seed(i,  16U);
77	state->s4 = __seed(i, 128U);
78}
79
80#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}
91static inline int arch_has_random(void)
92{
93	return 0;
94}
95static 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}
103static inline int arch_has_random_seed(void)
104{
105	return 0;
106}
107#endif
108
109/* Pseudo random number generator from numerical recipes. */
110static inline u32 next_pseudo_random32(u32 seed)
111{
112	return seed * 1664525 + 1013904223;
113}
114
115#endif /* _LINUX_RANDOM_H */
116