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
  14 struct random_ready_callback {
  15         struct list_head list;
  16         void (*func)(struct random_ready_callback *rdy);
  17         struct module *owner;
  18 };
  19
  20 extern void add_device_randomness(const void *, unsigned int);
  21
  22 #if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__)
  23 static inline void add_latent_entropy(void)
  24 {
  25         add_device_randomness((const void *)&latent_entropy,
  26                               sizeof(latent_entropy));
  27 }
  28 #else
  29 static inline void add_latent_entropy(void) {}
  30 #endif
  31
  32 extern void add_input_randomness(unsigned int type, unsigned int code,
  33                                  unsigned int value) __latent_entropy;
  34 extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
  35
  36 extern void get_random_bytes(void *buf, int nbytes);
  37 extern int add_random_ready_callback(struct random_ready_callback *rdy);
  38 extern void del_random_ready_callback(struct random_ready_callback *rdy);
  39 extern void get_random_bytes_arch(void *buf, int nbytes);
  40
  41 #ifndef MODULE
  42 extern const struct file_operations random_fops, urandom_fops;
  43 #endif
  44
  45 u32 get_random_u32(void);
  46 u64 get_random_u64(void);
  47 static inline unsigned int get_random_int(void)
  48 {
  49         return get_random_u32();
  50 }
  51 static inline unsigned long get_random_long(void)
  52 {
  53 #if BITS_PER_LONG == 64
  54         return get_random_u64();
  55 #else
  56         return get_random_u32();
  57 #endif
  58 }
  59
  60 unsigned long randomize_page(unsigned long start, unsigned long range);
  61
  62 u32 prandom_u32(void);
  63 void prandom_bytes(void *buf, size_t nbytes);
  64 void prandom_seed(u32 seed);
  65 void prandom_reseed_late(void);
  66
  67 struct rnd_state {
  68         __u32 s1, s2, s3, s4;
  69 };
  70
  71 u32 prandom_u32_state(struct rnd_state *state);
  72 void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
  73 void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
  74
  75 #define prandom_init_once(pcpu_state)                   \
  76         DO_ONCE(prandom_seed_full_state, (pcpu_state))
  77
  78 /**
  79  * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
  80  * @ep_ro: right open interval endpoint
  81  *
  82  * Returns a pseudo-random number that is in interval [0, ep_ro). Note
  83  * that the result depends on PRNG being well distributed in [0, ~0U]
  84  * u32 space. Here we use maximally equidistributed combined Tausworthe
  85  * generator, that is, prandom_u32(). This is useful when requesting a
  86  * random index of an array containing ep_ro elements, for example.
  87  *
  88  * Returns: pseudo-random number in interval [0, ep_ro)
  89  */
  90 static inline u32 prandom_u32_max(u32 ep_ro)
  91 {
  92         return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
  93 }
  94
  95 /*
  96  * Handle minimum values for seeds
  97  */
  98 static inline u32 __seed(u32 x, u32 m)
  99 {
 100         return (x < m) ? x + m : x;
 101 }
 102
 103 /**
 104  * prandom_seed_state - set seed for prandom_u32_state().
 105  * @state: pointer to state structure to receive the seed.
 106  * @seed: arbitrary 64-bit value to use as a seed.
 107  */
 108 static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
 109 {
 110         u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
 111
 112         state->s1 = __seed(i,   2U);
 113         state->s2 = __seed(i,   8U);
 114         state->s3 = __seed(i,  16U);
 115         state->s4 = __seed(i, 128U);
 116 }
 117
 118 #ifdef CONFIG_ARCH_RANDOM
 119 # include <asm/archrandom.h>
 120 #else
 121 static inline bool arch_get_random_long(unsigned long *v)
 122 {
 123         return 0;
 124 }
 125 static inline bool arch_get_random_int(unsigned int *v)
 126 {
 127         return 0;
 128 }
 129 static inline bool arch_has_random(void)
 130 {
 131         return 0;
 132 }
 133 static inline bool arch_get_random_seed_long(unsigned long *v)
 134 {
 135         return 0;
 136 }
 137 static inline bool arch_get_random_seed_int(unsigned int *v)
 138 {
 139         return 0;
 140 }
 141 static inline bool arch_has_random_seed(void)
 142 {
 143         return 0;
 144 }
 145 #endif
 146
 147 /* Pseudo random number generator from numerical recipes. */
 148 static inline u32 next_pseudo_random32(u32 seed)
 149 {
 150         return seed * 1664525 + 1013904223;
 151 }
 152
 153 #endif /* _LINUX_RANDOM_H */