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 u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key); 25 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 26 u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key); 27 #endif 28 29 u64 siphash_1u64(const u64 a, const siphash_key_t *key); 30 u64 siphash_2u64(const u64 a, const u64 b, const siphash_key_t *key); 31 u64 siphash_3u64(const u64 a, const u64 b, const u64 c, 32 const siphash_key_t *key); 33 u64 siphash_4u64(const u64 a, const u64 b, const u64 c, const u64 d, 34 const siphash_key_t *key); 35 u64 siphash_1u32(const u32 a, const siphash_key_t *key); 36 u64 siphash_3u32(const u32 a, const u32 b, const u32 c, 37 const siphash_key_t *key); 38 39 static inline u64 siphash_2u32(const u32 a, const u32 b, 40 const siphash_key_t *key) 41 { 42 return siphash_1u64((u64)b << 32 | a, key); 43 } 44 static inline u64 siphash_4u32(const u32 a, const u32 b, const u32 c, 45 const u32 d, const siphash_key_t *key) 46 { 47 return siphash_2u64((u64)b << 32 | a, (u64)d << 32 | c, key); 48 } 49 50 51 static inline u64 ___siphash_aligned(const __le64 *data, size_t len, 52 const siphash_key_t *key) 53 { 54 if (__builtin_constant_p(len) && len == 4) 55 return siphash_1u32(le32_to_cpup((const __le32 *)data), key); 56 if (__builtin_constant_p(len) && len == 8) 57 return siphash_1u64(le64_to_cpu(data[0]), key); 58 if (__builtin_constant_p(len) && len == 16) 59 return siphash_2u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]), 60 key); 61 if (__builtin_constant_p(len) && len == 24) 62 return siphash_3u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]), 63 le64_to_cpu(data[2]), key); 64 if (__builtin_constant_p(len) && len == 32) 65 return siphash_4u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]), 66 le64_to_cpu(data[2]), le64_to_cpu(data[3]), 67 key); 68 return __siphash_aligned(data, len, key); 69 } 70 71 /** 72 * siphash - compute 64-bit siphash PRF value 73 * @data: buffer to hash 74 * @size: size of @data 75 * @key: the siphash key 76 */ 77 static inline u64 siphash(const void *data, size_t len, 78 const siphash_key_t *key) 79 { 80 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 81 if (!IS_ALIGNED((unsigned long)data, SIPHASH_ALIGNMENT)) 82 return __siphash_unaligned(data, len, key); 83 #endif 84 return ___siphash_aligned(data, len, key); 85 } 86 87 #define HSIPHASH_ALIGNMENT __alignof__(unsigned long) 88 typedef struct { 89 unsigned long key[2]; 90 } hsiphash_key_t; 91 92 u32 __hsiphash_aligned(const void *data, size_t len, 93 const hsiphash_key_t *key); 94 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 95 u32 __hsiphash_unaligned(const void *data, size_t len, 96 const hsiphash_key_t *key); 97 #endif 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); 105 106 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 */ 130 static inline u32 hsiphash(const void *data, size_t len, 131 const hsiphash_key_t *key) 132 { 133 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 134 if (!IS_ALIGNED((unsigned long)data, HSIPHASH_ALIGNMENT)) 135 return __hsiphash_unaligned(data, len, key); 136 #endif 137 return ___hsiphash_aligned(data, len, key); 138 } 139 140 #endif /* _LINUX_SIPHASH_H */ 141