[linux-2.6-block.git] / include / linux / random.h

/*
 * 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);

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 */
Commit	Line	Data
	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	*/
	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	*/
	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	*/
	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
	83	static inline int arch_get_random_long(unsigned long *v)
	84	{
	85	return 0;
	86	}
	87	static inline int arch_get_random_int(unsigned int *v)
	88	{
	89	return 0;
	90	}
	91	static inline int arch_has_random(void)
	92	{
	93	return 0;
	94	}
	95	static inline int arch_get_random_seed_long(unsigned long *v)
	96	{
	97	return 0;
	98	}
	99	static inline int arch_get_random_seed_int(unsigned int *v)
	100	{
	101	return 0;
	102	}
	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. */
	110	static inline u32 next_pseudo_random32(u32 seed)
	111	{
	112	return seed * 1664525 + 1013904223;
	113	}
	114
	115	#endif /* _LINUX_RANDOM_H */