Line data    Source code

       1             : /* SPDX-License-Identifier: LGPL-2.1+ */
       2             : #pragma once
       3             : 
       4             : #include <stdbool.h>
       5             : #include <stddef.h>
       6             : #include <stdint.h>
       7             : 
       8             : typedef enum RandomFlags {
       9             :         RANDOM_EXTEND_WITH_PSEUDO = 1 << 0, /* If we can't get enough genuine randomness, but some, fill up the rest with pseudo-randomness */
      10             :         RANDOM_BLOCK              = 1 << 1, /* Rather block than return crap randomness (only if the kernel supports that) */
      11             :         RANDOM_MAY_FAIL           = 1 << 2, /* If we can't get any randomness at all, return early with -ENODATA */
      12             :         RANDOM_ALLOW_RDRAND       = 1 << 3, /* Allow usage of the CPU RNG */
      13             : } RandomFlags;
      14             : 
      15             : int genuine_random_bytes(void *p, size_t n, RandomFlags flags); /* returns "genuine" randomness, optionally filled up with pseudo random, if not enough is available */
      16             : void pseudo_random_bytes(void *p, size_t n);                    /* returns only pseudo-randommess (but possibly seeded from something better) */
      17             : void random_bytes(void *p, size_t n);                           /* returns genuine randomness if cheaply available, and pseudo randomness if not. */
      18             : 
      19             : void initialize_srand(void);
      20             : 
      21          45 : static inline uint64_t random_u64(void) {
      22             :         uint64_t u;
      23          45 :         random_bytes(&u, sizeof(u));
      24          45 :         return u;
      25             : }
      26             : 
      27          14 : static inline uint32_t random_u32(void) {
      28             :         uint32_t u;
      29          14 :         random_bytes(&u, sizeof(u));
      30          14 :         return u;
      31             : }
      32             : 
      33             : int rdrand(unsigned long *ret);
      34             : 
      35             : /* Some limits on the pool sizes when we deal with the kernel random pool */
      36             : #define RANDOM_POOL_SIZE_MIN 512U
      37             : #define RANDOM_POOL_SIZE_MAX (10U*1024U*1024U)
      38             : 
      39             : size_t random_pool_size(void);