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 extern int random_int_secret_init(void); 30 31 #ifndef MODULE 32 extern const struct file_operations random_fops, urandom_fops; 33 #endif 34 35 unsigned int get_random_int(void); 36 unsigned long get_random_long(void); 37 unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len); 38 39 u32 prandom_u32(void); 40 void prandom_bytes(void *buf, size_t nbytes); 41 void prandom_seed(u32 seed); 42 void prandom_reseed_late(void); 43 44 struct rnd_state { 45 __u32 s1, s2, s3, s4; 46 }; 47 48 u32 prandom_u32_state(struct rnd_state *state); 49 void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes); 50 void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state); 51 52 #define prandom_init_once(pcpu_state) \ 53 DO_ONCE(prandom_seed_full_state, (pcpu_state)) 54 55 /** 56 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro) 57 * @ep_ro: right open interval endpoint 58 * 59 * Returns a pseudo-random number that is in interval [0, ep_ro). Note 60 * that the result depends on PRNG being well distributed in [0, ~0U] 61 * u32 space. Here we use maximally equidistributed combined Tausworthe 62 * generator, that is, prandom_u32(). This is useful when requesting a 63 * random index of an array containing ep_ro elements, for example. 64 * 65 * Returns: pseudo-random number in interval [0, ep_ro) 66 */ 67 static inline u32 prandom_u32_max(u32 ep_ro) 68 { 69 return (u32)(((u64) prandom_u32() * ep_ro) >> 32); 70 } 71 72 /* 73 * Handle minimum values for seeds 74 */ 75 static inline u32 __seed(u32 x, u32 m) 76 { 77 return (x < m) ? x + m : x; 78 } 79 80 /** 81 * prandom_seed_state - set seed for prandom_u32_state(). 82 * @state: pointer to state structure to receive the seed. 83 * @seed: arbitrary 64-bit value to use as a seed. 84 */ 85 static inline void prandom_seed_state(struct rnd_state *state, u64 seed) 86 { 87 u32 i = (seed >> 32) ^ (seed << 10) ^ seed; 88 89 state->s1 = __seed(i, 2U); 90 state->s2 = __seed(i, 8U); 91 state->s3 = __seed(i, 16U); 92 state->s4 = __seed(i, 128U); 93 } 94 95 #ifdef CONFIG_ARCH_RANDOM 96 # include <asm/archrandom.h> 97 #else 98 static inline int arch_get_random_long(unsigned long *v) 99 { 100 return 0; 101 } 102 static inline int arch_get_random_int(unsigned int *v) 103 { 104 return 0; 105 } 106 static inline int arch_has_random(void) 107 { 108 return 0; 109 } 110 static inline int arch_get_random_seed_long(unsigned long *v) 111 { 112 return 0; 113 } 114 static inline int arch_get_random_seed_int(unsigned int *v) 115 { 116 return 0; 117 } 118 static inline int arch_has_random_seed(void) 119 { 120 return 0; 121 } 122 #endif 123 124 /* Pseudo random number generator from numerical recipes. */ 125 static inline u32 next_pseudo_random32(u32 seed) 126 { 127 return seed * 1664525 + 1013904223; 128 } 129 130 #endif /* _LINUX_RANDOM_H */ 131