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 extern void add_input_randomness(unsigned int type, unsigned int code,
  22                                  unsigned int value);
  23 extern void add_interrupt_randomness(int irq, int irq_flags);
  24
  25 extern void get_random_bytes(void *buf, int nbytes);
  26 extern int add_random_ready_callback(struct random_ready_callback *rdy);
  27 extern void del_random_ready_callback(struct random_ready_callback *rdy);
  28 extern void get_random_bytes_arch(void *buf, int nbytes);
  29 void generate_random_uuid(unsigned char uuid_out[16]);
  30 extern int random_int_secret_init(void);
  31
  32 #ifndef MODULE
  33 extern const struct file_operations random_fops, urandom_fops;
  34 #endif
  35
  36 unsigned int get_random_int(void);
  37 unsigned long get_random_long(void);
  38 unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
  39
  40 u32 prandom_u32(void);
  41 void prandom_bytes(void *buf, size_t nbytes);
  42 void prandom_seed(u32 seed);
  43 void prandom_reseed_late(void);
  44
  45 struct rnd_state {
  46         __u32 s1, s2, s3, s4;
  47 };
  48
  49 u32 prandom_u32_state(struct rnd_state *state);
  50 void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
  51 void 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  */
  68 static 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  */
  76 static 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  */
  86 static 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
  99 static inline int arch_get_random_long(unsigned long *v)
 100 {
 101         return 0;
 102 }
 103 static inline int arch_get_random_int(unsigned int *v)
 104 {
 105         return 0;
 106 }
 107 static inline int arch_has_random(void)
 108 {
 109         return 0;
 110 }
 111 static inline int arch_get_random_seed_long(unsigned long *v)
 112 {
 113         return 0;
 114 }
 115 static inline int arch_get_random_seed_int(unsigned int *v)
 116 {
 117         return 0;
 118 }
 119 static inline int arch_has_random_seed(void)
 120 {
 121         return 0;
 122 }
 123 #endif
 124
 125 /* Pseudo random number generator from numerical recipes. */
 126 static inline u32 next_pseudo_random32(u32 seed)
 127 {
 128         return seed * 1664525 + 1013904223;
 129 }
 130
 131 #endif /* _LINUX_RANDOM_H */