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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 */