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
  24u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key);
  25#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  26u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key);
  27#endif
  28
  29u64 siphash_1u64(const u64 a, const siphash_key_t *key);
  30u64 siphash_2u64(const u64 a, const u64 b, const siphash_key_t *key);
  31u64 siphash_3u64(const u64 a, const u64 b, const u64 c,
  32                 const siphash_key_t *key);
  33u64 siphash_4u64(const u64 a, const u64 b, const u64 c, const u64 d,
  34                 const siphash_key_t *key);
  35u64 siphash_1u32(const u32 a, const siphash_key_t *key);
  36u64 siphash_3u32(const u32 a, const u32 b, const u32 c,
  37                 const siphash_key_t *key);
  38
  39static 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}
  44static 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
  51static 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 */
  77static 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)
  88typedef struct {
  89        unsigned long key[2];
  90} hsiphash_key_t;
  91
  92u32 __hsiphash_aligned(const void *data, size_t len,
  93                       const hsiphash_key_t *key);
  94#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  95u32 __hsiphash_unaligned(const void *data, size_t len,
  96                         const hsiphash_key_t *key);
  97#endif
  98
  99u32 hsiphash_1u32(const u32 a, const hsiphash_key_t *key);
 100u32 hsiphash_2u32(const u32 a, const u32 b, const hsiphash_key_t *key);
 101u32 hsiphash_3u32(const u32 a, const u32 b, const u32 c,
 102                  const hsiphash_key_t *key);
 103u32 hsiphash_4u32(const u32 a, const u32 b, const u32 c, const u32 d,
 104                  const hsiphash_key_t *key);
 105
 106static 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 */
 130static 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