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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
24#define siphash_aligned_key_t siphash_key_t __aligned(16)
25
26static inline bool siphash_key_is_zero(const siphash_key_t *key)
27{
28 return !(key->key[0] | key->key[1]);
29}
30
31u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key);
32u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key);
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 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ||
86 !IS_ALIGNED((unsigned long)data, SIPHASH_ALIGNMENT))
87 return __siphash_unaligned(data, len, key);
88 return ___siphash_aligned(data, len, key);
89}
90
91#define HSIPHASH_ALIGNMENT __alignof__(unsigned long)
92typedef struct {
93 unsigned long key[2];
94} hsiphash_key_t;
95
96u32 __hsiphash_aligned(const void *data, size_t len,
97 const hsiphash_key_t *key);
98u32 __hsiphash_unaligned(const void *data, size_t len,
99 const hsiphash_key_t *key);
100
101u32 hsiphash_1u32(const u32 a, const hsiphash_key_t *key);
102u32 hsiphash_2u32(const u32 a, const u32 b, const hsiphash_key_t *key);
103u32 hsiphash_3u32(const u32 a, const u32 b, const u32 c,
104 const hsiphash_key_t *key);
105u32 hsiphash_4u32(const u32 a, const u32 b, const u32 c, const u32 d,
106 const hsiphash_key_t *key);
107
108static inline u32 ___hsiphash_aligned(const __le32 *data, size_t len,
109 const hsiphash_key_t *key)
110{
111 if (__builtin_constant_p(len) && len == 4)
112 return hsiphash_1u32(le32_to_cpu(data[0]), key);
113 if (__builtin_constant_p(len) && len == 8)
114 return hsiphash_2u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]),
115 key);
116 if (__builtin_constant_p(len) && len == 12)
117 return hsiphash_3u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]),
118 le32_to_cpu(data[2]), key);
119 if (__builtin_constant_p(len) && len == 16)
120 return hsiphash_4u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]),
121 le32_to_cpu(data[2]), le32_to_cpu(data[3]),
122 key);
123 return __hsiphash_aligned(data, len, key);
124}
125
126/**
127 * hsiphash - compute 32-bit hsiphash PRF value
128 * @data: buffer to hash
129 * @size: size of @data
130 * @key: the hsiphash key
131 */
132static inline u32 hsiphash(const void *data, size_t len,
133 const hsiphash_key_t *key)
134{
135 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ||
136 !IS_ALIGNED((unsigned long)data, HSIPHASH_ALIGNMENT))
137 return __hsiphash_unaligned(data, len, key);
138 return ___hsiphash_aligned(data, len, key);
139}
140
141#endif /* _LINUX_SIPHASH_H */