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