Linux kernel mirror (for testing)
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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 <linux/list.h>
10#include <linux/once.h>
11
12#include <uapi/linux/random.h>
13
14struct random_ready_callback {
15 struct list_head list;
16 void (*func)(struct random_ready_callback *rdy);
17 struct module *owner;
18};
19
20extern void add_device_randomness(const void *, unsigned int);
21
22#if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__)
23static inline void add_latent_entropy(void)
24{
25 add_device_randomness((const void *)&latent_entropy,
26 sizeof(latent_entropy));
27}
28#else
29static inline void add_latent_entropy(void) {}
30#endif
31
32extern void add_input_randomness(unsigned int type, unsigned int code,
33 unsigned int value) __latent_entropy;
34extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
35
36extern void get_random_bytes(void *buf, int nbytes);
37extern int add_random_ready_callback(struct random_ready_callback *rdy);
38extern void del_random_ready_callback(struct random_ready_callback *rdy);
39extern void get_random_bytes_arch(void *buf, int nbytes);
40extern int random_int_secret_init(void);
41
42#ifndef MODULE
43extern const struct file_operations random_fops, urandom_fops;
44#endif
45
46unsigned int get_random_int(void);
47unsigned long get_random_long(void);
48unsigned long randomize_page(unsigned long start, unsigned long range);
49
50u32 prandom_u32(void);
51void prandom_bytes(void *buf, size_t nbytes);
52void prandom_seed(u32 seed);
53void prandom_reseed_late(void);
54
55struct rnd_state {
56 __u32 s1, s2, s3, s4;
57};
58
59u32 prandom_u32_state(struct rnd_state *state);
60void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
61void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
62
63#define prandom_init_once(pcpu_state) \
64 DO_ONCE(prandom_seed_full_state, (pcpu_state))
65
66/**
67 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
68 * @ep_ro: right open interval endpoint
69 *
70 * Returns a pseudo-random number that is in interval [0, ep_ro). Note
71 * that the result depends on PRNG being well distributed in [0, ~0U]
72 * u32 space. Here we use maximally equidistributed combined Tausworthe
73 * generator, that is, prandom_u32(). This is useful when requesting a
74 * random index of an array containing ep_ro elements, for example.
75 *
76 * Returns: pseudo-random number in interval [0, ep_ro)
77 */
78static inline u32 prandom_u32_max(u32 ep_ro)
79{
80 return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
81}
82
83/*
84 * Handle minimum values for seeds
85 */
86static inline u32 __seed(u32 x, u32 m)
87{
88 return (x < m) ? x + m : x;
89}
90
91/**
92 * prandom_seed_state - set seed for prandom_u32_state().
93 * @state: pointer to state structure to receive the seed.
94 * @seed: arbitrary 64-bit value to use as a seed.
95 */
96static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
97{
98 u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
99
100 state->s1 = __seed(i, 2U);
101 state->s2 = __seed(i, 8U);
102 state->s3 = __seed(i, 16U);
103 state->s4 = __seed(i, 128U);
104}
105
106#ifdef CONFIG_ARCH_RANDOM
107# include <asm/archrandom.h>
108#else
109static inline bool arch_get_random_long(unsigned long *v)
110{
111 return 0;
112}
113static inline bool arch_get_random_int(unsigned int *v)
114{
115 return 0;
116}
117static inline bool arch_has_random(void)
118{
119 return 0;
120}
121static inline bool arch_get_random_seed_long(unsigned long *v)
122{
123 return 0;
124}
125static inline bool arch_get_random_seed_int(unsigned int *v)
126{
127 return 0;
128}
129static inline bool arch_has_random_seed(void)
130{
131 return 0;
132}
133#endif
134
135/* Pseudo random number generator from numerical recipes. */
136static inline u32 next_pseudo_random32(u32 seed)
137{
138 return seed * 1664525 + 1013904223;
139}
140
141#endif /* _LINUX_RANDOM_H */