LXR linux/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)
  20typedef struct {
  21        u64 key[2];
  22} siphash_key_t;
  23
  24static inline bool siphash_key_is_zero(const siphash_key_t *key)
  25{
  26        return !(key->key[0] | key->key[1]);
  27}
  28
  29u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key);
  30#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  31u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key);
  32#endif
  33
  34u64 siphash_1u64(const u64 a, const siphash_key_t *key);
  35u64 siphash_2u64(const u64 a, const u64 b, const siphash_key_t *key);
  36u64 siphash_3u64(const u64 a, const u64 b, const u64 c,
  37                 const siphash_key_t *key);
  38u64 siphash_4u64(const u64 a, const u64 b, const u64 c, const u64 d,
  39                 const siphash_key_t *key);
  40u64 siphash_1u32(const u32 a, const siphash_key_t *key);
  41u64 siphash_3u32(const u32 a, const u32 b, const u32 c,
  42                 const siphash_key_t *key);
  43
  44static 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}
  49static 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
  56static 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 */
  82static 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)
  93typedef struct {
  94        unsigned long key[2];
  95} hsiphash_key_t;
  96
  97u32 __hsiphash_aligned(const void *data, size_t len,
  98                       const hsiphash_key_t *key);
  99#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 100u32 __hsiphash_unaligned(const void *data, size_t len,
 101                         const hsiphash_key_t *key);
 102#endif
 103
 104u32 hsiphash_1u32(const u32 a, const hsiphash_key_t *key);
 105u32 hsiphash_2u32(const u32 a, const u32 b, const hsiphash_key_t *key);
 106u32 hsiphash_3u32(const u32 a, const u32 b, const u32 c,
 107                  const hsiphash_key_t *key);
 108u32 hsiphash_4u32(const u32 a, const u32 b, const u32 c, const u32 d,
 109                  const hsiphash_key_t *key);
 110
 111static 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 */
 135static 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