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) 19 typedef struct { 20 u64 key[2]; 21 } siphash_key_t; 22 23 #define siphash_aligned_key_t siphash_key_t __aligned(16) 24 25 static inline bool siphash_key_is_zero(const siphash_key_t *key) 26 { 27 return !(key->key[0] | key->key[1]); 28 } 29 30 u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key); 31 u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key); 32 33 u64 siphash_1u64(const u64 a, const siphash_key_t *key); 34 u64 siphash_2u64(const u64 a, const u64 b, const siphash_key_t *key); 35 u64 siphash_3u64(const u64 a, const u64 b, const u64 c, 36 const siphash_key_t *key); 37 u64 siphash_4u64(const u64 a, const u64 b, const u64 c, const u64 d, 38 const siphash_key_t *key); 39 u64 siphash_1u32(const u32 a, const siphash_key_t *key); 40 u64 siphash_3u32(const u32 a, const u32 b, const u32 c, 41 const siphash_key_t *key); 42 43 static 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 } 48 static 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 55 static 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 * @len: size of @data 79 * @key: the siphash key 80 * 81 * Returns: siphash PRF value 82 */ 83 static inline u64 siphash(const void *data, size_t len, 84 const siphash_key_t *key) 85 { 86 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || 87 !IS_ALIGNED((unsigned long)data, SIPHASH_ALIGNMENT)) 88 return __siphash_unaligned(data, len, key); 89 return ___siphash_aligned(data, len, key); 90 } 91 92 #define HSIPHASH_ALIGNMENT __alignof__(unsigned long) 93 typedef struct { 94 unsigned long key[2]; 95 } hsiphash_key_t; 96 97 u32 __hsiphash_aligned(const void *data, size_t len, 98 const hsiphash_key_t *key); 99 u32 __hsiphash_unaligned(const void *data, size_t len, 100 const hsiphash_key_t *key); 101 102 u32 hsiphash_1u32(const u32 a, const hsiphash_key_t *key); 103 u32 hsiphash_2u32(const u32 a, const u32 b, const hsiphash_key_t *key); 104 u32 hsiphash_3u32(const u32 a, const u32 b, const u32 c, 105 const hsiphash_key_t *key); 106 u32 hsiphash_4u32(const u32 a, const u32 b, const u32 c, const u32 d, 107 const hsiphash_key_t *key); 108 109 static inline u32 ___hsiphash_aligned(const __le32 *data, size_t len, 110 const hsiphash_key_t *key) 111 { 112 if (__builtin_constant_p(len) && len == 4) 113 return hsiphash_1u32(le32_to_cpu(data[0]), key); 114 if (__builtin_constant_p(len) && len == 8) 115 return hsiphash_2u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 116 key); 117 if (__builtin_constant_p(len) && len == 12) 118 return hsiphash_3u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 119 le32_to_cpu(data[2]), key); 120 if (__builtin_constant_p(len) && len == 16) 121 return hsiphash_4u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 122 le32_to_cpu(data[2]), le32_to_cpu(data[3]), 123 key); 124 return __hsiphash_aligned(data, len, key); 125 } 126 127 /** 128 * hsiphash - compute 32-bit hsiphash PRF value 129 * @data: buffer to hash 130 * @len: size of @data 131 * @key: the hsiphash key 132 * 133 * Returns: hsiphash PRF value 134 */ 135 static inline u32 hsiphash(const void *data, size_t len, 136 const hsiphash_key_t *key) 137 { 138 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || 139 !IS_ALIGNED((unsigned long)data, HSIPHASH_ALIGNMENT)) 140 return __hsiphash_unaligned(data, len, key); 141 return ___hsiphash_aligned(data, len, key); 142 } 143 144 /* 145 * These macros expose the raw SipHash and HalfSipHash permutations. 146 * Do not use them directly! If you think you have a use for them, 147 * be sure to CC the maintainer of this file explaining why. 148 */ 149 150 #define SIPHASH_PERMUTATION(a, b, c, d) ( \ 151 (a) += (b), (b) = rol64((b), 13), (b) ^= (a), (a) = rol64((a), 32), \ 152 (c) += (d), (d) = rol64((d), 16), (d) ^= (c), \ 153 (a) += (d), (d) = rol64((d), 21), (d) ^= (a), \ 154 (c) += (b), (b) = rol64((b), 17), (b) ^= (c), (c) = rol64((c), 32)) 155 156 #define SIPHASH_CONST_0 0x736f6d6570736575ULL 157 #define SIPHASH_CONST_1 0x646f72616e646f6dULL 158 #define SIPHASH_CONST_2 0x6c7967656e657261ULL 159 #define SIPHASH_CONST_3 0x7465646279746573ULL 160 161 #define HSIPHASH_PERMUTATION(a, b, c, d) ( \ 162 (a) += (b), (b) = rol32((b), 5), (b) ^= (a), (a) = rol32((a), 16), \ 163 (c) += (d), (d) = rol32((d), 8), (d) ^= (c), \ 164 (a) += (d), (d) = rol32((d), 7), (d) ^= (a), \ 165 (c) += (b), (b) = rol32((b), 13), (b) ^= (c), (c) = rol32((c), 16)) 166 167 #define HSIPHASH_CONST_0 0U 168 #define HSIPHASH_CONST_1 0U 169 #define HSIPHASH_CONST_2 0x6c796765U 170 #define HSIPHASH_CONST_3 0x74656462U 171 172 #endif /* _LINUX_SIPHASH_H */ 173