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 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 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 31 u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key); 32 #endif 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 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 86 if (!IS_ALIGNED((unsigned long)data, SIPHASH_ALIGNMENT)) 87 return __siphash_unaligned(data, len, key); 88 #endif 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 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 100 u32 __hsiphash_unaligned(const void *data, size_t len, 101 const hsiphash_key_t *key); 102 #endif 103 104 u32 hsiphash_1u32(const u32 a, const hsiphash_key_t *key); 105 u32 hsiphash_2u32(const u32 a, const u32 b, const hsiphash_key_t *key); 106 u32 hsiphash_3u32(const u32 a, const u32 b, const u32 c, 107 const hsiphash_key_t *key); 108 u32 hsiphash_4u32(const u32 a, const u32 b, const u32 c, const u32 d, 109 const hsiphash_key_t *key); 110 111 static inline u32 ___hsiphash_aligned(const __le32 *data, size_t len, 112 const hsiphash_key_t *key) 113 { 114 if (__builtin_constant_p(len) && len == 4) 115 return hsiphash_1u32(le32_to_cpu(data[0]), key); 116 if (__builtin_constant_p(len) && len == 8) 117 return hsiphash_2u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 118 key); 119 if (__builtin_constant_p(len) && len == 12) 120 return hsiphash_3u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 121 le32_to_cpu(data[2]), key); 122 if (__builtin_constant_p(len) && len == 16) 123 return hsiphash_4u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]), 124 le32_to_cpu(data[2]), le32_to_cpu(data[3]), 125 key); 126 return __hsiphash_aligned(data, len, key); 127 } 128 129 /** 130 * hsiphash - compute 32-bit hsiphash PRF value 131 * @data: buffer to hash 132 * @size: size of @data 133 * @key: the hsiphash key 134 */ 135 static inline u32 hsiphash(const void *data, size_t len, 136 const hsiphash_key_t *key) 137 { 138 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 139 if (!IS_ALIGNED((unsigned long)data, HSIPHASH_ALIGNMENT)) 140 return __hsiphash_unaligned(data, len, key); 141 #endif 142 return ___hsiphash_aligned(data, len, key); 143 } 144 145 #endif /* _LINUX_SIPHASH_H */ 146