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