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