diff options
Diffstat (limited to 'siphash.c')
| -rw-r--r-- | siphash.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/siphash.c b/siphash.c new file mode 100644 index 0000000..63cc2c6 --- /dev/null +++ b/siphash.c @@ -0,0 +1,204 @@ +/* SPDX-License-Identifier: MIT + * + * Copyright (C) 2016-2019 WireGuard LLC. All Rights Reserved. + * + * SipHash: a fast short-input PRF + * https://131002.net/siphash/ + */ + +#include "siphash.h" + +static inline uint64_t rol64(uint64_t word, unsigned int shift) +{ + return (word << shift) | (word >> (64 - shift)); +} + +#define SIPROUND \ + do { \ + v0 += v1; \ + v1 = rol64(v1, 13); \ + v1 ^= v0; \ + v0 = rol64(v0, 32); \ + v2 += v3; \ + v3 = rol64(v3, 16); \ + v3 ^= v2; \ + v0 += v3; \ + v3 = rol64(v3, 21); \ + v3 ^= v0; \ + v2 += v1; \ + v1 = rol64(v1, 17); \ + v1 ^= v2; \ + v2 = rol64(v2, 32); \ + } while (0) + +#define PREAMBLE(len) \ + uint64_t v0 = 0x736f6d6570736575ULL; \ + uint64_t v1 = 0x646f72616e646f6dULL; \ + uint64_t v2 = 0x6c7967656e657261ULL; \ + uint64_t v3 = 0x7465646279746573ULL; \ + uint64_t b = ((uint64_t)(len)) << 56; \ + v3 ^= key->key[1]; \ + v2 ^= key->key[0]; \ + v1 ^= key->key[1]; \ + v0 ^= key->key[0]; + +#define POSTAMBLE \ + v3 ^= b; \ + SIPROUND; \ + SIPROUND; \ + v0 ^= b; \ + v2 ^= 0xff; \ + SIPROUND; \ + SIPROUND; \ + SIPROUND; \ + SIPROUND; \ + return (v0 ^ v1) ^ (v2 ^ v3); + +uint64_t __siphash_aligned(const void *data, size_t len, + const siphash_key_t *key) +{ + const uint8_t *end = data + len - (len % sizeof(uint64_t)); + const uint8_t left = len & (sizeof(uint64_t) - 1); + uint64_t m; + PREAMBLE(len) + for (; data != end; data += sizeof(uint64_t)) { + m = le64toh(*((uint64_t *)data)); + v3 ^= m; + SIPROUND; + SIPROUND; + v0 ^= m; + } + switch (left) { + case 7: + b |= ((uint64_t)end[6]) << 48; /* fall through */ + case 6: + b |= ((uint64_t)end[5]) << 40; /* fall through */ + case 5: + b |= ((uint64_t)end[4]) << 32; /* fall through */ + case 4: + b |= le32toh(*((uint32_t *)data)); + break; + case 3: + b |= ((uint64_t)end[2]) << 16; /* fall through */ + case 2: + b |= le16toh(*((uint16_t *)data)); + break; + case 1: + b |= end[0]; + } + POSTAMBLE +} + +/** + * siphash_1u64 - compute 64-bit siphash PRF value of a u64 + * @first: first u64 + * @key: the siphash key + */ +uint64_t siphash_1u64(const uint64_t first, const siphash_key_t *key) +{ + PREAMBLE(8) + v3 ^= first; + SIPROUND; + SIPROUND; + v0 ^= first; + POSTAMBLE +} + +/** + * siphash_2u64 - compute 64-bit siphash PRF value of 2 u64 + * @first: first u64 + * @second: second u64 + * @key: the siphash key + */ +uint64_t siphash_2u64(const uint64_t first, const uint64_t second, + const siphash_key_t *key) +{ + PREAMBLE(16) + v3 ^= first; + SIPROUND; + SIPROUND; + v0 ^= first; + v3 ^= second; + SIPROUND; + SIPROUND; + v0 ^= second; + POSTAMBLE +} + +/** + * siphash_3u64 - compute 64-bit siphash PRF value of 3 u64 + * @first: first u64 + * @second: second u64 + * @third: third u64 + * @key: the siphash key + */ +uint64_t siphash_3u64(const uint64_t first, const uint64_t second, + const uint64_t third, const siphash_key_t *key) +{ + PREAMBLE(24) + v3 ^= first; + SIPROUND; + SIPROUND; + v0 ^= first; + v3 ^= second; + SIPROUND; + SIPROUND; + v0 ^= second; + v3 ^= third; + SIPROUND; + SIPROUND; + v0 ^= third; + POSTAMBLE +} + +/** + * siphash_4u64 - compute 64-bit siphash PRF value of 4 u64 + * @first: first u64 + * @second: second u64 + * @third: third u64 + * @forth: forth u64 + * @key: the siphash key + */ +uint64_t siphash_4u64(const uint64_t first, const uint64_t second, + const uint64_t third, const uint64_t forth, + const siphash_key_t *key) +{ + PREAMBLE(32) + v3 ^= first; + SIPROUND; + SIPROUND; + v0 ^= first; + v3 ^= second; + SIPROUND; + SIPROUND; + v0 ^= second; + v3 ^= third; + SIPROUND; + SIPROUND; + v0 ^= third; + v3 ^= forth; + SIPROUND; + SIPROUND; + v0 ^= forth; + POSTAMBLE +} + +uint64_t siphash_1u32(const uint32_t first, const siphash_key_t *key) +{ + PREAMBLE(4) + b |= first; + POSTAMBLE +} + +uint64_t siphash_3u32(const uint32_t first, const uint32_t second, + const uint32_t third, const siphash_key_t *key) +{ + uint64_t combined = (uint64_t)second << 32 | first; + PREAMBLE(12) + v3 ^= combined; + SIPROUND; + SIPROUND; + v0 ^= combined; + b |= third; + POSTAMBLE +} |