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]);
30 extern int random_int_secret_init(void);
33 extern const struct file_operations random_fops
, urandom_fops
;
36 unsigned int get_random_int(void);
37 unsigned long randomize_range(unsigned long start
, unsigned long end
, unsigned long len
);
39 u32
prandom_u32(void);
40 void prandom_bytes(void *buf
, size_t nbytes
);
41 void prandom_seed(u32 seed
);
42 void prandom_reseed_late(void);
48 u32
prandom_u32_state(struct rnd_state
*state
);
49 void prandom_bytes_state(struct rnd_state
*state
, void *buf
, size_t nbytes
);
50 void prandom_seed_full_state(struct rnd_state __percpu
*pcpu_state
);
52 #define prandom_init_once(pcpu_state) \
53 DO_ONCE(prandom_seed_full_state, (pcpu_state))
56 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
57 * @ep_ro: right open interval endpoint
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.
65 * Returns: pseudo-random number in interval [0, ep_ro)
67 static inline u32
prandom_u32_max(u32 ep_ro
)
69 return (u32
)(((u64
) prandom_u32() * ep_ro
) >> 32);
73 * Handle minimum values for seeds
75 static inline u32
__seed(u32 x
, u32 m
)
77 return (x
< m
) ? x
+ m
: x
;
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.
85 static inline void prandom_seed_state(struct rnd_state
*state
, u64 seed
)
87 u32 i
= (seed
>> 32) ^ (seed
<< 10) ^ seed
;
89 state
->s1
= __seed(i
, 2U);
90 state
->s2
= __seed(i
, 8U);
91 state
->s3
= __seed(i
, 16U);
92 state
->s4
= __seed(i
, 128U);
95 #ifdef CONFIG_ARCH_RANDOM
96 # include <asm/archrandom.h>
98 static inline int arch_get_random_long(unsigned long *v
)
102 static inline int arch_get_random_int(unsigned int *v
)
106 static inline int arch_has_random(void)
110 static inline int arch_get_random_seed_long(unsigned long *v
)
114 static inline int arch_get_random_seed_int(unsigned int *v
)
118 static inline int arch_has_random_seed(void)
124 /* Pseudo random number generator from numerical recipes. */
125 static inline u32
next_pseudo_random32(u32 seed
)
127 return seed
* 1664525 + 1013904223;
130 #endif /* _LINUX_RANDOM_H */