1 /* Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. 2 * 3 * This file is provided under a dual BSD/GPLv2 license. 4 * 5 * SipHash: a fast short-input PRF 6 * https://131002.net/siphash/ 7 * 8 * This implementation is specifically for SipHash2-4 for a secure PRF 9 * and HalfSipHash1-3/SipHash1-3 for an insecure PRF only suitable for 10 * hashtables. 11 */ 12 13 #ifndef _LINUX_SIPHASH_H 14 #define _LINUX_SIPHASH_H 15 16 #include <linux/types.h> 17 #include <linux/kernel.h> 18 19 #define SIPHASH_ALIGNMENT __alignof__(u64) 20 typedef struct { 21 u64 key[2]; 22 } siphash_key_t; 23 24 #define siphash_aligned_key_t siphash_key_t __aligned(16) 25 26 static inline bool siphash_key_is_zero(const siphash_key_t *key) 27 { 28 return !(key->key[0] | key->key[1]); 29 } 30 31 u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key); 32 u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key); 33 34 u64 siphash_1u64(const u64 a, const siphash_key_t *key); 35 u64 siphash_2u64(const u64 a, const u64 b, const siphash_key_t *key); 36 u64 siphash_3u64(const u64 a, const u64 b, const u64 c, 37 const siphash_key_t *key); 38 u64 siphash_4u64(const u64 a, const u64 b, const u64 c, const u64 d, 39 const siphash_key_t *key); 40 u64 siphash_1u32(const u32 a, const siphash_key_t *key); 41 u64 siphash_3u32(const u32 a, const u32 b, const u32 c, 42 const siphash_key_t *key); 43 44 static inline u64 siphash_2u32(const u32 a, const u32 b, 45 const siphash_key_t *key) 46 { 47 return siphash_1u64((u64)b << 32 | a, key); 48 } 49 static inline u64 siphash_4u32(const u32 a, const u32 b, const u32 c, 50 const u32 d, const siphash_key_t *key) 51 { 52 return siphash_2u64((u64)b << 32 | a, (u64)d << 32 | c, key); 53 } 54 55 56 static inline u64 ___siphash_aligned(const __le64 *data, size_t len, 57 const siphash_key_t *key) 58 { 59 if (__builtin_constant_p(len) && len == 4) 60 return siphash_1u32(le32_to_cpup((const __le32 *)data), key); 61 if (__builtin_constant_p(len) && len == 8) 62 return siphash_1u64(le64_to_cpu(data[0]), key); 63 if (__builtin_constant_p(len) && len == 16) 64 return siphash_2u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]), 65 key); 66 if (__builtin_constant_p(len) && len == 24) 67 return siphash_3u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]), 68 le64_to_cpu(data[2]), key); 69 if (__builtin_constant_p(len) && len == 32) 70 return siphash_4u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]), 71 le64_to_cpu(data[2]), le64_to_cpu(data[3]), 72 key); 73 return __siphash_aligned(data, len, key); 74 } 75 76 /** 77 * siphash - compute 64-bit siphash PRF value 78 * @data: buffer to hash 79 * @size: size of @data 80 * @key: the siphash key 81 */ 82 static inline u64 siphash(const void *data, size_t len, 83 const siphash_key_t *key) 84 { 85 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || 86 !IS_ALIGNED((unsigned long)data, SIPHASH_ALIGNMENT)) 87 return __siphash_unaligned(data, len, key); 88 return ___siphash_aligned(data, len, key); 89 } 90 91 #define HSIPHASH_ALIGNMENT __alignof__(unsigned long) 92 typedef struct { 93 unsigned long key[2]; 94 } hsiphash_key_t; 95 96 u32 __hsiphash_aligned(const void *data, size_t len, 97 const hsiphash_key_t *key); 98 u32 __hsiphash_unaligned(const void *data, size_t len, 99 const hsiphash_key_t *key); 100 101 u32 hsiphash_1u32(const u32 a, const hsiphash_key_t *key); 102 u32 hsiphash_2u32(const u32 a, const u32 b, const hsiphash_key_t *key); 103 u32 hsiphash_3u32(const u32 a, const u32 b, const u32 c, 104 const hsiphash_key_t *key); 105 u32 hsiphash_4u32(const u32 a, const u32 b, const u32 c, const u32 d, 106 const hsiphash_key_t *key); 107 108 static inline u32 ___hsiphash_aligned(const __le32 *data, size_t len, 109 const hsiphash_key_t *key) 110 { 111 if (__builtin_constant_p(len) && len == 4) 112 return hsiphash_1u32(le32_to_cpu(data[0]), key); 113 if (__builtin_constant_p(len) && len == 8) 114 return hsiphash_2u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 115 key); 116 if (__builtin_constant_p(len) && len == 12) 117 return hsiphash_3u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 118 le32_to_cpu(data[2]), key); 119 if (__builtin_constant_p(len) && len == 16) 120 return hsiphash_4u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 121 le32_to_cpu(data[2]), le32_to_cpu(data[3]), 122 key); 123 return __hsiphash_aligned(data, len, key); 124 } 125 126 /** 127 * hsiphash - compute 32-bit hsiphash PRF value 128 * @data: buffer to hash 129 * @size: size of @data 130 * @key: the hsiphash key 131 */ 132 static inline u32 hsiphash(const void *data, size_t len, 133 const hsiphash_key_t *key) 134 { 135 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || 136 !IS_ALIGNED((unsigned long)data, HSIPHASH_ALIGNMENT)) 137 return __hsiphash_unaligned(data, len, key); 138 return ___hsiphash_aligned(data, len, key); 139 } 140 141 /* 142 * These macros expose the raw SipHash and HalfSipHash permutations. 143 * Do not use them directly! If you think you have a use for them, 144 * be sure to CC the maintainer of this file explaining why. 145 */ 146 147 #define SIPHASH_PERMUTATION(a, b, c, d) ( \ 148 (a) += (b), (b) = rol64((b), 13), (b) ^= (a), (a) = rol64((a), 32), \ 149 (c) += (d), (d) = rol64((d), 16), (d) ^= (c), \ 150 (a) += (d), (d) = rol64((d), 21), (d) ^= (a), \ 151 (c) += (b), (b) = rol64((b), 17), (b) ^= (c), (c) = rol64((c), 32)) 152 153 #define SIPHASH_CONST_0 0x736f6d6570736575ULL 154 #define SIPHASH_CONST_1 0x646f72616e646f6dULL 155 #define SIPHASH_CONST_2 0x6c7967656e657261ULL 156 #define SIPHASH_CONST_3 0x7465646279746573ULL 157 158 #define HSIPHASH_PERMUTATION(a, b, c, d) ( \ 159 (a) += (b), (b) = rol32((b), 5), (b) ^= (a), (a) = rol32((a), 16), \ 160 (c) += (d), (d) = rol32((d), 8), (d) ^= (c), \ 161 (a) += (d), (d) = rol32((d), 7), (d) ^= (a), \ 162 (c) += (b), (b) = rol32((b), 13), (b) ^= (c), (c) = rol32((c), 16)) 163 164 #define HSIPHASH_CONST_0 0U 165 #define HSIPHASH_CONST_1 0U 166 #define HSIPHASH_CONST_2 0x6c796765U 167 #define HSIPHASH_CONST_3 0x74656462U 168 169 #endif /* _LINUX_SIPHASH_H */ 170