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 */ 116