projects/linux·blob v4.8 · refs

130 lines · 3.3 KiB

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