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