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 <linux/once.h>
  11
  12#include <uapi/linux/random.h>
  13
  14struct random_ready_callback {
  15        struct list_head list;
  16        void (*func)(struct random_ready_callback *rdy);
  17        struct module *owner;
  18};
  19
  20extern void add_device_randomness(const void *, unsigned int);
  21
  22#if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__)
  23static inline void add_latent_entropy(void)
  24{
  25        add_device_randomness((const void *)&latent_entropy,
  26                              sizeof(latent_entropy));
  27}
  28#else
  29static inline void add_latent_entropy(void) {}
  30#endif
  31
  32extern void add_input_randomness(unsigned int type, unsigned int code,
  33                                 unsigned int value) __latent_entropy;
  34extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
  35
  36extern void get_random_bytes(void *buf, int nbytes);
  37extern int add_random_ready_callback(struct random_ready_callback *rdy);
  38extern void del_random_ready_callback(struct random_ready_callback *rdy);
  39extern void get_random_bytes_arch(void *buf, int nbytes);
  40extern int random_int_secret_init(void);
  41
  42#ifndef MODULE
  43extern const struct file_operations random_fops, urandom_fops;
  44#endif
  45
  46unsigned int get_random_int(void);
  47unsigned long get_random_long(void);
  48unsigned long randomize_page(unsigned long start, unsigned long range);
  49
  50u32 prandom_u32(void);
  51void prandom_bytes(void *buf, size_t nbytes);
  52void prandom_seed(u32 seed);
  53void prandom_reseed_late(void);
  54
  55struct rnd_state {
  56        __u32 s1, s2, s3, s4;
  57};
  58
  59u32 prandom_u32_state(struct rnd_state *state);
  60void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
  61void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
  62
  63#define prandom_init_once(pcpu_state)                   \
  64        DO_ONCE(prandom_seed_full_state, (pcpu_state))
  65
  66/**
  67 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
  68 * @ep_ro: right open interval endpoint
  69 *
  70 * Returns a pseudo-random number that is in interval [0, ep_ro). Note
  71 * that the result depends on PRNG being well distributed in [0, ~0U]
  72 * u32 space. Here we use maximally equidistributed combined Tausworthe
  73 * generator, that is, prandom_u32(). This is useful when requesting a
  74 * random index of an array containing ep_ro elements, for example.
  75 *
  76 * Returns: pseudo-random number in interval [0, ep_ro)
  77 */
  78static inline u32 prandom_u32_max(u32 ep_ro)
  79{
  80        return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
  81}
  82
  83/*
  84 * Handle minimum values for seeds
  85 */
  86static inline u32 __seed(u32 x, u32 m)
  87{
  88        return (x < m) ? x + m : x;
  89}
  90
  91/**
  92 * prandom_seed_state - set seed for prandom_u32_state().
  93 * @state: pointer to state structure to receive the seed.
  94 * @seed: arbitrary 64-bit value to use as a seed.
  95 */
  96static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
  97{
  98        u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
  99
 100        state->s1 = __seed(i,   2U);
 101        state->s2 = __seed(i,   8U);
 102        state->s3 = __seed(i,  16U);
 103        state->s4 = __seed(i, 128U);
 104}
 105
 106#ifdef CONFIG_ARCH_RANDOM
 107# include <asm/archrandom.h>
 108#else
 109static inline bool arch_get_random_long(unsigned long *v)
 110{
 111        return 0;
 112}
 113static inline bool arch_get_random_int(unsigned int *v)
 114{
 115        return 0;
 116}
 117static inline bool arch_has_random(void)
 118{
 119        return 0;
 120}
 121static inline bool arch_get_random_seed_long(unsigned long *v)
 122{
 123        return 0;
 124}
 125static inline bool arch_get_random_seed_int(unsigned int *v)
 126{
 127        return 0;
 128}
 129static inline bool arch_has_random_seed(void)
 130{
 131        return 0;
 132}
 133#endif
 134
 135/* Pseudo random number generator from numerical recipes. */
 136static inline u32 next_pseudo_random32(u32 seed)
 137{
 138        return seed * 1664525 + 1013904223;
 139}
 140
 141#endif /* _LINUX_RANDOM_H */
 142