src/basic/random-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <stdbool.h>
   5 #include <stddef.h>
   6 #include <stdint.h>
   7
   8 void random_bytes(void *p, size_t n); /* Returns random bytes suitable for most uses, but may be insecure sometimes. */
   9 int crypto_random_bytes(void *p, size_t n); /* Returns secure random bytes after waiting for the RNG to initialize. */
  10
  11 static inline uint64_t random_u64(void) {
  12         uint64_t u;
  13         random_bytes(&u, sizeof(u));
  14         return u;
  15 }
  16
  17 static inline uint32_t random_u32(void) {
  18         uint32_t u;
  19         random_bytes(&u, sizeof(u));
  20         return u;
  21 }
  22
  23 /* Some limits on the pool sizes when we deal with the kernel random pool */
  24 #define RANDOM_POOL_SIZE_MIN 32U
  25 #define RANDOM_POOL_SIZE_MAX (10U*1024U*1024U)
  26 #define RANDOM_EFI_SEED_SIZE 32U
  27
  28 size_t random_pool_size(void);
  29
  30 int random_write_entropy(int fd, const void *seed, size_t size, bool credit);
  31
  32 uint64_t random_u64_range(uint64_t max);