diff options
Diffstat (limited to 'kernel/include/linux/random.h')
-rw-r--r-- | kernel/include/linux/random.h | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/kernel/include/linux/random.h b/kernel/include/linux/random.h new file mode 100644 index 000000000..4a64ad52d --- /dev/null +++ b/kernel/include/linux/random.h @@ -0,0 +1,115 @@ +/* + * include/linux/random.h + * + * Include file for the random number generator. + */ +#ifndef _LINUX_RANDOM_H +#define _LINUX_RANDOM_H + +#include <uapi/linux/random.h> + +extern void add_device_randomness(const void *, unsigned int); +extern void add_input_randomness(unsigned int type, unsigned int code, + unsigned int value); +extern void add_interrupt_randomness(int irq, int irq_flags, __u64 ip); + +extern void get_random_bytes(void *buf, int nbytes); +extern void get_random_bytes_arch(void *buf, int nbytes); +void generate_random_uuid(unsigned char uuid_out[16]); +extern int random_int_secret_init(void); + +#ifndef MODULE +extern const struct file_operations random_fops, urandom_fops; +#endif + +unsigned int get_random_int(void); +unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len); + +u32 prandom_u32(void); +void prandom_bytes(void *buf, size_t nbytes); +void prandom_seed(u32 seed); +void prandom_reseed_late(void); + +struct rnd_state { + __u32 s1, s2, s3, s4; +}; + +u32 prandom_u32_state(struct rnd_state *state); +void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes); + +/** + * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro) + * @ep_ro: right open interval endpoint + * + * Returns a pseudo-random number that is in interval [0, ep_ro). Note + * that the result depends on PRNG being well distributed in [0, ~0U] + * u32 space. Here we use maximally equidistributed combined Tausworthe + * generator, that is, prandom_u32(). This is useful when requesting a + * random index of an array containing ep_ro elements, for example. + * + * Returns: pseudo-random number in interval [0, ep_ro) + */ +static inline u32 prandom_u32_max(u32 ep_ro) +{ + return (u32)(((u64) prandom_u32() * ep_ro) >> 32); +} + +/* + * Handle minimum values for seeds + */ +static inline u32 __seed(u32 x, u32 m) +{ + return (x < m) ? x + m : x; +} + +/** + * prandom_seed_state - set seed for prandom_u32_state(). + * @state: pointer to state structure to receive the seed. + * @seed: arbitrary 64-bit value to use as a seed. + */ +static inline void prandom_seed_state(struct rnd_state *state, u64 seed) +{ + u32 i = (seed >> 32) ^ (seed << 10) ^ seed; + + state->s1 = __seed(i, 2U); + state->s2 = __seed(i, 8U); + state->s3 = __seed(i, 16U); + state->s4 = __seed(i, 128U); +} + +#ifdef CONFIG_ARCH_RANDOM +# include <asm/archrandom.h> +#else +static inline int arch_get_random_long(unsigned long *v) +{ + return 0; +} +static inline int arch_get_random_int(unsigned int *v) +{ + return 0; +} +static inline int arch_has_random(void) +{ + return 0; +} +static inline int arch_get_random_seed_long(unsigned long *v) +{ + return 0; +} +static inline int arch_get_random_seed_int(unsigned int *v) +{ + return 0; +} +static inline int arch_has_random_seed(void) +{ + return 0; +} +#endif + +/* Pseudo random number generator from numerical recipes. */ +static inline u32 next_pseudo_random32(u32 seed) +{ + return seed * 1664525 + 1013904223; +} + +#endif /* _LINUX_RANDOM_H */ |