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 */ 125