1/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */ 2/* Copyright (C) 2016-2022 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. 3 * 4 * SipHash: a fast short-input PRF 5 * https://131002.net/siphash/ 6 * 7 * This implementation is specifically for SipHash2-4 for a secure PRF 8 * and HalfSipHash1-3/SipHash1-3 for an insecure PRF only suitable for 9 * hashtables. 10 */ 11 12#ifndef _LINUX_SIPHASH_H 13#define _LINUX_SIPHASH_H 14 15#include <linux/types.h> 16#include <linux/kernel.h> 17 18#define SIPHASH_ALIGNMENT __alignof__(u64) 19typedef struct { 20 u64 key[2]; 21} siphash_key_t; 22 23#define siphash_aligned_key_t siphash_key_t __aligned(16) 24 25static inline bool siphash_key_is_zero(const siphash_key_t *key) 26{ 27 return !(key->key[0] | key->key[1]); 28} 29 30u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key); 31u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key); 32 33u64 siphash_1u64(const u64 a, const siphash_key_t *key); 34u64 siphash_2u64(const u64 a, const u64 b, const siphash_key_t *key); 35u64 siphash_3u64(const u64 a, const u64 b, const u64 c, 36 const siphash_key_t *key); 37u64 siphash_4u64(const u64 a, const u64 b, const u64 c, const u64 d, 38 const siphash_key_t *key); 39u64 siphash_1u32(const u32 a, const siphash_key_t *key); 40u64 siphash_3u32(const u32 a, const u32 b, const u32 c, 41 const siphash_key_t *key); 42 43static inline u64 siphash_2u32(const u32 a, const u32 b, 44 const siphash_key_t *key) 45{ 46 return siphash_1u64((u64)b << 32 | a, key); 47} 48static inline u64 siphash_4u32(const u32 a, const u32 b, const u32 c, 49 const u32 d, const siphash_key_t *key) 50{ 51 return siphash_2u64((u64)b << 32 | a, (u64)d << 32 | c, key); 52} 53 54 55static inline u64 ___siphash_aligned(const __le64 *data, size_t len, 56 const siphash_key_t *key) 57{ 58 if (__builtin_constant_p(len) && len == 4) 59 return siphash_1u32(le32_to_cpup((const __le32 *)data), key); 60 if (__builtin_constant_p(len) && len == 8) 61 return siphash_1u64(le64_to_cpu(data[0]), key); 62 if (__builtin_constant_p(len) && len == 16) 63 return siphash_2u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]), 64 key); 65 if (__builtin_constant_p(len) && len == 24) 66 return siphash_3u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]), 67 le64_to_cpu(data[2]), key); 68 if (__builtin_constant_p(len) && len == 32) 69 return siphash_4u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]), 70 le64_to_cpu(data[2]), le64_to_cpu(data[3]), 71 key); 72 return __siphash_aligned(data, len, key); 73} 74 75/** 76 * siphash - compute 64-bit siphash PRF value 77 * @data: buffer to hash 78 * @size: size of @data 79 * @key: the siphash key 80 */ 81static inline u64 siphash(const void *data, size_t len, 82 const siphash_key_t *key) 83{ 84 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || 85 !IS_ALIGNED((unsigned long)data, SIPHASH_ALIGNMENT)) 86 return __siphash_unaligned(data, len, key); 87 return ___siphash_aligned(data, len, key); 88} 89 90#define HSIPHASH_ALIGNMENT __alignof__(unsigned long) 91typedef struct { 92 unsigned long key[2]; 93} hsiphash_key_t; 94 95u32 __hsiphash_aligned(const void *data, size_t len, 96 const hsiphash_key_t *key); 97u32 __hsiphash_unaligned(const void *data, size_t len, 98 const hsiphash_key_t *key); 99 100u32 hsiphash_1u32(const u32 a, const hsiphash_key_t *key); 101u32 hsiphash_2u32(const u32 a, const u32 b, const hsiphash_key_t *key); 102u32 hsiphash_3u32(const u32 a, const u32 b, const u32 c, 103 const hsiphash_key_t *key); 104u32 hsiphash_4u32(const u32 a, const u32 b, const u32 c, const u32 d, 105 const hsiphash_key_t *key); 106 107static inline u32 ___hsiphash_aligned(const __le32 *data, size_t len, 108 const hsiphash_key_t *key) 109{ 110 if (__builtin_constant_p(len) && len == 4) 111 return hsiphash_1u32(le32_to_cpu(data[0]), key); 112 if (__builtin_constant_p(len) && len == 8) 113 return hsiphash_2u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 114 key); 115 if (__builtin_constant_p(len) && len == 12) 116 return hsiphash_3u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 117 le32_to_cpu(data[2]), key); 118 if (__builtin_constant_p(len) && len == 16) 119 return hsiphash_4u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 120 le32_to_cpu(data[2]), le32_to_cpu(data[3]), 121 key); 122 return __hsiphash_aligned(data, len, key); 123} 124 125/** 126 * hsiphash - compute 32-bit hsiphash PRF value 127 * @data: buffer to hash 128 * @size: size of @data 129 * @key: the hsiphash key 130 */ 131static inline u32 hsiphash(const void *data, size_t len, 132 const hsiphash_key_t *key) 133{ 134 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || 135 !IS_ALIGNED((unsigned long)data, HSIPHASH_ALIGNMENT)) 136 return __hsiphash_unaligned(data, len, key); 137 return ___hsiphash_aligned(data, len, key); 138} 139 140/* 141 * These macros expose the raw SipHash and HalfSipHash permutations. 142 * Do not use them directly! If you think you have a use for them, 143 * be sure to CC the maintainer of this file explaining why. 144 */ 145 146#define SIPHASH_PERMUTATION(a, b, c, d) ( \ 147 (a) += (b), (b) = rol64((b), 13), (b) ^= (a), (a) = rol64((a), 32), \ 148 (c) += (d), (d) = rol64((d), 16), (d) ^= (c), \ 149 (a) += (d), (d) = rol64((d), 21), (d) ^= (a), \ 150 (c) += (b), (b) = rol64((b), 17), (b) ^= (c), (c) = rol64((c), 32)) 151 152#define SIPHASH_CONST_0 0x736f6d6570736575ULL 153#define SIPHASH_CONST_1 0x646f72616e646f6dULL 154#define SIPHASH_CONST_2 0x6c7967656e657261ULL 155#define SIPHASH_CONST_3 0x7465646279746573ULL 156 157#define HSIPHASH_PERMUTATION(a, b, c, d) ( \ 158 (a) += (b), (b) = rol32((b), 5), (b) ^= (a), (a) = rol32((a), 16), \ 159 (c) += (d), (d) = rol32((d), 8), (d) ^= (c), \ 160 (a) += (d), (d) = rol32((d), 7), (d) ^= (a), \ 161 (c) += (b), (b) = rol32((b), 13), (b) ^= (c), (c) = rol32((c), 16)) 162 163#define HSIPHASH_CONST_0 0U 164#define HSIPHASH_CONST_1 0U 165#define HSIPHASH_CONST_2 0x6c796765U 166#define HSIPHASH_CONST_3 0x74656462U 167 168#endif /* _LINUX_SIPHASH_H */ 169