LXR linux/include/linux/random.h

   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 <linux/list.h>
  10#include <uapi/linux/random.h>
  11
  12struct random_ready_callback {
  13        struct list_head list;
  14        void (*func)(struct random_ready_callback *rdy);
  15        struct module *owner;
  16};
  17
  18extern void add_device_randomness(const void *, unsigned int);
  19extern void add_input_randomness(unsigned int type, unsigned int code,
  20                                 unsigned int value);
  21extern void add_interrupt_randomness(int irq, int irq_flags);
  22
  23extern void get_random_bytes(void *buf, int nbytes);
  24extern int add_random_ready_callback(struct random_ready_callback *rdy);
  25extern void del_random_ready_callback(struct random_ready_callback *rdy);
  26extern void get_random_bytes_arch(void *buf, int nbytes);
  27void generate_random_uuid(unsigned char uuid_out[16]);
  28extern int random_int_secret_init(void);
  29
  30#ifndef MODULE
  31extern const struct file_operations random_fops, urandom_fops;
  32#endif
  33
  34unsigned int get_random_int(void);
  35unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
  36
  37u32 prandom_u32(void);
  38void prandom_bytes(void *buf, size_t nbytes);
  39void prandom_seed(u32 seed);
  40void prandom_reseed_late(void);
  41
  42struct rnd_state {
  43        __u32 s1, s2, s3, s4;
  44};
  45
  46u32 prandom_u32_state(struct rnd_state *state);
  47void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
  48
  49/**
  50 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
  51 * @ep_ro: right open interval endpoint
  52 *
  53 * Returns a pseudo-random number that is in interval [0, ep_ro). Note
  54 * that the result depends on PRNG being well distributed in [0, ~0U]
  55 * u32 space. Here we use maximally equidistributed combined Tausworthe
  56 * generator, that is, prandom_u32(). This is useful when requesting a
  57 * random index of an array containing ep_ro elements, for example.
  58 *
  59 * Returns: pseudo-random number in interval [0, ep_ro)
  60 */
  61static inline u32 prandom_u32_max(u32 ep_ro)
  62{
  63        return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
  64}
  65
  66/*
  67 * Handle minimum values for seeds
  68 */
  69static inline u32 __seed(u32 x, u32 m)
  70{
  71        return (x < m) ? x + m : x;
  72}
  73
  74/**
  75 * prandom_seed_state - set seed for prandom_u32_state().
  76 * @state: pointer to state structure to receive the seed.
  77 * @seed: arbitrary 64-bit value to use as a seed.
  78 */
  79static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
  80{
  81        u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
  82
  83        state->s1 = __seed(i,   2U);
  84        state->s2 = __seed(i,   8U);
  85        state->s3 = __seed(i,  16U);
  86        state->s4 = __seed(i, 128U);
  87}
  88
  89#ifdef CONFIG_ARCH_RANDOM
  90# include <asm/archrandom.h>
  91#else
  92static inline int arch_get_random_long(unsigned long *v)
  93{
  94        return 0;
  95}
  96static inline int arch_get_random_int(unsigned int *v)
  97{
  98        return 0;
  99}
 100static inline int arch_has_random(void)
 101{
 102        return 0;
 103}
 104static inline int arch_get_random_seed_long(unsigned long *v)
 105{
 106        return 0;
 107}
 108static inline int arch_get_random_seed_int(unsigned int *v)
 109{
 110        return 0;
 111}
 112static inline int arch_has_random_seed(void)
 113{
 114        return 0;
 115}
 116#endif
 117
 118/* Pseudo random number generator from numerical recipes. */
 119static inline u32 next_pseudo_random32(u32 seed)
 120{
 121        return seed * 1664525 + 1013904223;
 122}
 123
 124#endif /* _LINUX_RANDOM_H */
 125