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 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 */