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/* 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
}
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