linux_kernel/include/linux/random.h

/*
 * include/linux/random.h
 *
 * Include file for the random number generator.
 */

#ifndef _LINUX_RANDOM_H
#define _LINUX_RANDOM_H

#include <linux/types.h>
#include <linux/ioctl.h>
#include <linux/irqnr.h>

/* ioctl()'s for the random number generator */

/* Get the entropy count. */
#define RNDGETENTCNT	_IOR( 'R', 0x00, int )

/* Add to (or subtract from) the entropy count.  (Superuser only.) */
#define RNDADDTOENTCNT	_IOW( 'R', 0x01, int )

/* Get the contents of the entropy pool.  (Superuser only.) */
#define RNDGETPOOL	_IOR( 'R', 0x02, int [2] )

/* 
 * Write bytes into the entropy pool and add to the entropy count.
 * (Superuser only.)
 */
#define RNDADDENTROPY	_IOW( 'R', 0x03, int [2] )

/* Clear entropy count to 0.  (Superuser only.) */
#define RNDZAPENTCNT	_IO( 'R', 0x04 )

/* Clear the entropy pool and associated counters.  (Superuser only.) */
#define RNDCLEARPOOL	_IO( 'R', 0x06 )

struct rand_pool_info {
	int	entropy_count;
	int	buf_size;
	__u32	buf[0];
};

struct rnd_state {
	__u32 s1, s2, s3;
};

/* Exported functions */

#ifdef __KERNEL__

extern void rand_initialize_irq(int irq);

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);
void generate_random_uuid(unsigned char uuid_out[16]);

#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 random32(void);
void srandom32(u32 seed);

u32 prandom32(struct rnd_state *);

/*
 * Handle minimum values for seeds
 */
static inline u32 __seed(u32 x, u32 m)
{
	return (x < m) ? x + m : x;
}

/**
 * prandom32_seed - set seed for prandom32().
 * @state: pointer to state structure to receive the seed.
 * @seed: arbitrary 64-bit value to use as a seed.
 */
static inline void prandom32_seed(struct rnd_state *state, u64 seed)
{
	u32 i = (seed >> 32) ^ (seed << 10) ^ seed;

	state->s1 = __seed(i, 1);
	state->s2 = __seed(i, 7);
	state->s3 = __seed(i, 15);
}

#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;
}
#endif

#endif /* __KERNEL___ */

#endif /* _LINUX_RANDOM_H */