2 * include/linux/random.h
4 * Include file for the random number generator.
6 #ifndef _LINUX_RANDOM_H
7 #define _LINUX_RANDOM_H
9 #include <linux/list.h>
10 #include <linux/once.h>
12 #include <uapi/linux/random.h>
14 struct random_ready_callback {
15 struct list_head list;
16 void (*func)(struct random_ready_callback *rdy);
20 extern void add_device_randomness(const void *, unsigned int);
21 extern void add_input_randomness(unsigned int type, unsigned int code,
23 extern void add_interrupt_randomness(int irq, int irq_flags);
25 extern void get_random_bytes(void *buf, int nbytes);
26 extern int add_random_ready_callback(struct random_ready_callback *rdy);
27 extern void del_random_ready_callback(struct random_ready_callback *rdy);
28 extern void get_random_bytes_arch(void *buf, int nbytes);
29 void generate_random_uuid(unsigned char uuid_out[16]);
32 extern const struct file_operations random_fops, urandom_fops;
35 u32 get_random_u32(void);
36 u64 get_random_u64(void);
37 static inline unsigned int get_random_int(void)
39 return get_random_u32();
41 static inline unsigned long get_random_long(void)
43 #if BITS_PER_LONG == 64
44 return get_random_u64();
46 return get_random_u32();
49 unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
51 u32 prandom_u32(void);
52 void prandom_bytes(void *buf, size_t nbytes);
53 void prandom_seed(u32 seed);
54 void prandom_reseed_late(void);
60 u32 prandom_u32_state(struct rnd_state *state);
61 void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
62 void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
64 #define prandom_init_once(pcpu_state) \
65 DO_ONCE(prandom_seed_full_state, (pcpu_state))
68 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
69 * @ep_ro: right open interval endpoint
71 * Returns a pseudo-random number that is in interval [0, ep_ro). Note
72 * that the result depends on PRNG being well distributed in [0, ~0U]
73 * u32 space. Here we use maximally equidistributed combined Tausworthe
74 * generator, that is, prandom_u32(). This is useful when requesting a
75 * random index of an array containing ep_ro elements, for example.
77 * Returns: pseudo-random number in interval [0, ep_ro)
79 static inline u32 prandom_u32_max(u32 ep_ro)
81 return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
85 * Handle minimum values for seeds
87 static inline u32 __seed(u32 x, u32 m)
89 return (x < m) ? x + m : x;
93 * prandom_seed_state - set seed for prandom_u32_state().
94 * @state: pointer to state structure to receive the seed.
95 * @seed: arbitrary 64-bit value to use as a seed.
97 static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
99 u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
101 state->s1 = __seed(i, 2U);
102 state->s2 = __seed(i, 8U);
103 state->s3 = __seed(i, 16U);
104 state->s4 = __seed(i, 128U);
107 #ifdef CONFIG_ARCH_RANDOM
108 # include <asm/archrandom.h>
110 static inline bool arch_get_random_long(unsigned long *v)
114 static inline bool arch_get_random_int(unsigned int *v)
118 static inline bool arch_has_random(void)
122 static inline bool arch_get_random_seed_long(unsigned long *v)
126 static inline bool arch_get_random_seed_int(unsigned int *v)
130 static inline bool arch_has_random_seed(void)
136 /* Pseudo random number generator from numerical recipes. */
137 static inline u32 next_pseudo_random32(u32 seed)
139 return seed * 1664525 + 1013904223;
142 #endif /* _LINUX_RANDOM_H */