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
11 extern void add_device_randomness(const void *, unsigned int);
12 extern void add_input_randomness(unsigned int type, unsigned int code,
13 unsigned int value);
14 extern void add_interrupt_randomness(int irq, int irq_flags);
15
16 extern void get_random_bytes(void *buf, int nbytes);
17 extern void get_random_bytes_arch(void *buf, int nbytes);
18 void generate_random_uuid(unsigned char uuid_out[16]);
19 extern int random_int_secret_init(void);
20
21 #ifndef MODULE
22 extern const struct file_operations random_fops, urandom_fops;
23 #endif
24
25 unsigned int get_random_int(void);
26 unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
27
28 u32 prandom_u32(void);
29 void prandom_bytes(void *buf, size_t nbytes);
30 void prandom_seed(u32 seed);
31 void prandom_reseed_late(void);
32
33 struct rnd_state {
34 __u32 s1, s2, s3, s4;
35 };
36
37 u32 prandom_u32_state(struct rnd_state *state);
38 void 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 */
prandom_u32_max(u32 ep_ro)52 static 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 */
__seed(u32 x,u32 m)60 static 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 */
prandom_seed_state(struct rnd_state * state,u64 seed)70 static 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
arch_get_random_long(unsigned long * v)83 static inline int arch_get_random_long(unsigned long *v)
84 {
85 return 0;
86 }
arch_get_random_int(unsigned int * v)87 static inline int arch_get_random_int(unsigned int *v)
88 {
89 return 0;
90 }
arch_has_random(void)91 static inline int arch_has_random(void)
92 {
93 return 0;
94 }
arch_get_random_seed_long(unsigned long * v)95 static inline int arch_get_random_seed_long(unsigned long *v)
96 {
97 return 0;
98 }
arch_get_random_seed_int(unsigned int * v)99 static inline int arch_get_random_seed_int(unsigned int *v)
100 {
101 return 0;
102 }
arch_has_random_seed(void)103 static inline int arch_has_random_seed(void)
104 {
105 return 0;
106 }
107 #endif
108
109 /* Pseudo random number generator from numerical recipes. */
next_pseudo_random32(u32 seed)110 static inline u32 next_pseudo_random32(u32 seed)
111 {
112 return seed * 1664525 + 1013904223;
113 }
114
115 #endif /* _LINUX_RANDOM_H */
116