blob: feeb29cd113ed9b443e8544540887c6ccb44b4ee [file] [log] [blame]
Jason A. Donenfeld53e054b2019-08-17 00:01:12 +01001/* 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.
9 */
10
11#ifndef _LINUX_SIPHASH_H
12#define _LINUX_SIPHASH_H
13
14#include <linux/types.h>
15#include <linux/kernel.h>
16
17#define SIPHASH_ALIGNMENT __alignof__(u64)
18typedef struct {
19 u64 key[2];
20} siphash_key_t;
21
22u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key);
23#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
24u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key);
25#endif
26
27u64 siphash_1u64(const u64 a, const siphash_key_t *key);
28u64 siphash_2u64(const u64 a, const u64 b, const siphash_key_t *key);
29u64 siphash_3u64(const u64 a, const u64 b, const u64 c,
30 const siphash_key_t *key);
31u64 siphash_4u64(const u64 a, const u64 b, const u64 c, const u64 d,
32 const siphash_key_t *key);
33u64 siphash_1u32(const u32 a, const siphash_key_t *key);
34u64 siphash_3u32(const u32 a, const u32 b, const u32 c,
35 const siphash_key_t *key);
36
37static inline u64 siphash_2u32(const u32 a, const u32 b,
38 const siphash_key_t *key)
39{
40 return siphash_1u64((u64)b << 32 | a, key);
41}
42static inline u64 siphash_4u32(const u32 a, const u32 b, const u32 c,
43 const u32 d, const siphash_key_t *key)
44{
45 return siphash_2u64((u64)b << 32 | a, (u64)d << 32 | c, key);
46}
47
48
49static inline u64 ___siphash_aligned(const __le64 *data, size_t len,
50 const siphash_key_t *key)
51{
52 if (__builtin_constant_p(len) && len == 4)
53 return siphash_1u32(le32_to_cpup((const __le32 *)data), key);
54 if (__builtin_constant_p(len) && len == 8)
55 return siphash_1u64(le64_to_cpu(data[0]), key);
56 if (__builtin_constant_p(len) && len == 16)
57 return siphash_2u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]),
58 key);
59 if (__builtin_constant_p(len) && len == 24)
60 return siphash_3u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]),
61 le64_to_cpu(data[2]), key);
62 if (__builtin_constant_p(len) && len == 32)
63 return siphash_4u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]),
64 le64_to_cpu(data[2]), le64_to_cpu(data[3]),
65 key);
66 return __siphash_aligned(data, len, key);
67}
68
69/**
70 * siphash - compute 64-bit siphash PRF value
71 * @data: buffer to hash
72 * @size: size of @data
73 * @key: the siphash key
74 */
75static inline u64 siphash(const void *data, size_t len,
76 const siphash_key_t *key)
77{
78#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
79 if (!IS_ALIGNED((unsigned long)data, SIPHASH_ALIGNMENT))
80 return __siphash_unaligned(data, len, key);
81#endif
82 return ___siphash_aligned(data, len, key);
83}
84
85#endif /* _LINUX_SIPHASH_H */