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
siphash_2u32(const u32 a,const u32 b,const siphash_key_t * key)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 }
siphash_4u32(const u32 a,const u32 b,const u32 c,const u32 d,const siphash_key_t * key)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
___siphash_aligned(const __le64 * data,size_t len,const siphash_key_t * key)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 */
siphash(const void * data,size_t len,const siphash_key_t * key)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
___hsiphash_aligned(const __le32 * data,size_t len,const hsiphash_key_t * key)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 */
hsiphash(const void * data,size_t len,const hsiphash_key_t * key)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 */
141
