include/linux/siphash.h

   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 */