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 get_random_long(void);
  38unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
  39
  40u32 prandom_u32(void);
  41void prandom_bytes(void *buf, size_t nbytes);
  42void prandom_seed(u32 seed);
  43void prandom_reseed_late(void);
  44
  45struct rnd_state {
  46        __u32 s1, s2, s3, s4;
  47};
  48
  49u32 prandom_u32_state(struct rnd_state *state);
  50void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
  51void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
  52
  53#define prandom_init_once(pcpu_state)                   \
  54        DO_ONCE(prandom_seed_full_state, (pcpu_state))
  55
  56/**
  57 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
  58 * @ep_ro: right open interval endpoint
  59 *
  60 * Returns a pseudo-random number that is in interval [0, ep_ro). Note
  61 * that the result depends on PRNG being well distributed in [0, ~0U]
  62 * u32 space. Here we use maximally equidistributed combined Tausworthe
  63 * generator, that is, prandom_u32(). This is useful when requesting a
  64 * random index of an array containing ep_ro elements, for example.
  65 *
  66 * Returns: pseudo-random number in interval [0, ep_ro)
  67 */
  68static inline u32 prandom_u32_max(u32 ep_ro)
  69{
  70        return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
  71}
  72
  73/*
  74 * Handle minimum values for seeds
  75 */
  76static inline u32 __seed(u32 x, u32 m)
  77{
  78        return (x < m) ? x + m : x;
  79}
  80
  81/**
  82 * prandom_seed_state - set seed for prandom_u32_state().
  83 * @state: pointer to state structure to receive the seed.
  84 * @seed: arbitrary 64-bit value to use as a seed.
  85 */
  86static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
  87{
  88        u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
  89
  90        state->s1 = __seed(i,   2U);
  91        state->s2 = __seed(i,   8U);
  92        state->s3 = __seed(i,  16U);
  93        state->s4 = __seed(i, 128U);
  94}
  95
  96#ifdef CONFIG_ARCH_RANDOM
  97# include <asm/archrandom.h>
  98#else
  99static inline int arch_get_random_long(unsigned long *v)
 100{
 101        return 0;
 102}
 103static inline int arch_get_random_int(unsigned int *v)
 104{
 105        return 0;
 106}
 107static inline int arch_has_random(void)
 108{
 109        return 0;
 110}
 111static inline int arch_get_random_seed_long(unsigned long *v)
 112{
 113        return 0;
 114}
 115static inline int arch_get_random_seed_int(unsigned int *v)
 116{
 117        return 0;
 118}
 119static inline int arch_has_random_seed(void)
 120{
 121        return 0;
 122}
 123#endif
 124
 125/* Pseudo random number generator from numerical recipes. */
 126static inline u32 next_pseudo_random32(u32 seed)
 127{
 128        return seed * 1664525 + 1013904223;
 129}
 130
 131#endif /* _LINUX_RANDOM_H */
 132