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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
3df3e884 RC |
2 | #pragma once |
3 | ||
f0d09059 | 4 | #include <stdbool.h> |
11c3a366 | 5 | #include <stddef.h> |
3df3e884 RC |
6 | #include <stdint.h> |
7 | ||
94d457e8 LP |
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 */ | |
68534345 | 10 | RANDOM_BLOCK = 1 << 1, /* Rather block than return crap randomness (only if the kernel supports that) */ |
1a0ffa1e | 11 | RANDOM_MAY_FAIL = 1 << 2, /* If we can't get any randomness at all, return early with -ENODATA */ |
cc83d519 | 12 | RANDOM_ALLOW_RDRAND = 1 << 3, /* Allow usage of the CPU RNG */ |
0497c4c2 | 13 | RANDOM_ALLOW_INSECURE = 1 << 4, /* Allow usage of GRND_INSECURE flag to kernel's getrandom() API */ |
94d457e8 LP |
14 | } RandomFlags; |
15 | ||
1a0ffa1e | 16 | 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 */ |
94d457e8 LP |
17 | void pseudo_random_bytes(void *p, size_t n); /* returns only pseudo-randommess (but possibly seeded from something better) */ |
18 | void random_bytes(void *p, size_t n); /* returns genuine randomness if cheaply available, and pseudo randomness if not. */ | |
3335dc2d | 19 | |
3df3e884 RC |
20 | void initialize_srand(void); |
21 | ||
22 | static inline uint64_t random_u64(void) { | |
23 | uint64_t u; | |
24 | random_bytes(&u, sizeof(u)); | |
25 | return u; | |
26 | } | |
27 | ||
28 | static inline uint32_t random_u32(void) { | |
29 | uint32_t u; | |
30 | random_bytes(&u, sizeof(u)); | |
31 | return u; | |
32 | } | |
97fa202a | 33 | |
33dbab6f | 34 | int rdrand(unsigned long *ret); |
3e155eba LP |
35 | |
36 | /* Some limits on the pool sizes when we deal with the kernel random pool */ | |
37 | #define RANDOM_POOL_SIZE_MIN 512U | |
38 | #define RANDOM_POOL_SIZE_MAX (10U*1024U*1024U) | |
39 | ||
40 | size_t random_pool_size(void); | |
4dd055f9 LP |
41 | |
42 | int random_write_entropy(int fd, const void *seed, size_t size, bool credit); |