summaryrefslogtreecommitdiff
path: root/lib/siphash.c
blob: c43cf406e71b240326a515e20ae853f878baa61a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
/* Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 *
 * This file is provided under a dual BSD/GPLv2 license.
 *
 * SipHash: a fast short-input PRF
 * https://131002.net/siphash/
 *
 * This implementation is specifically for SipHash2-4.
 */

#include <linux/siphash.h>
#include <asm/unaligned.h>

#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
#include <linux/dcache.h>
#include <asm/word-at-a-time.h>
#endif

#define SIPROUND \
	do { \
	v0 += v1; v1 = rol64(v1, 13); v1 ^= v0; v0 = rol64(v0, 32); \
	v2 += v3; v3 = rol64(v3, 16); v3 ^= v2; \
	v0 += v3; v3 = rol64(v3, 21); v3 ^= v0; \
	v2 += v1; v1 = rol64(v1, 17); v1 ^= v2; v2 = rol64(v2, 32); \
	} while (0)

#define PREAMBLE(len) \
	u64 v0 = 0x736f6d6570736575ULL; \
	u64 v1 = 0x646f72616e646f6dULL; \
	u64 v2 = 0x6c7967656e657261ULL; \
	u64 v3 = 0x7465646279746573ULL; \
	u64 b = ((u64)(len)) << 56; \
	v3 ^= key->key[1]; \
	v2 ^= key->key[0]; \
	v1 ^= key->key[1]; \
	v0 ^= key->key[0];

#define POSTAMBLE \
	v3 ^= b; \
	SIPROUND; \
	SIPROUND; \
	v0 ^= b; \
	v2 ^= 0xff; \
	SIPROUND; \
	SIPROUND; \
	SIPROUND; \
	SIPROUND; \
	return (v0 ^ v1) ^ (v2 ^ v3);

u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key)
{
	const u8 *end = data + len - (len % sizeof(u64));
	const u8 left = len & (sizeof(u64) - 1);
	u64 m;
	PREAMBLE(len)
	for (; data != end; data += sizeof(u64)) {
		m = le64_to_cpup(data);
		v3 ^= m;
		SIPROUND;
		SIPROUND;
		v0 ^= m;
	}
#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
	if (left)
		b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) &
						  bytemask_from_count(left)));
#else
	switch (left) {
	case 7: b |= ((u64)end[6]) << 48;
	case 6: b |= ((u64)end[5]) << 40;
	case 5: b |= ((u64)end[4]) << 32;
	case 4: b |= le32_to_cpup(data); break;
	case 3: b |= ((u64)end[2]) << 16;
	case 2: b |= le16_to_cpup(data); break;
	case 1: b |= end[0];
	}
#endif
	POSTAMBLE
}
EXPORT_SYMBOL(__siphash_aligned);

#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key)
{
	const u8 *end = data + len - (len % sizeof(u64));
	const u8 left = len & (sizeof(u64) - 1);
	u64 m;
	PREAMBLE(len)
	for (; data != end; data += sizeof(u64)) {
		m = get_unaligned_le64(data);
		v3 ^= m;
		SIPROUND;
		SIPROUND;
		v0 ^= m;
	}
#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
	if (left)
		b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) &
						  bytemask_from_count(left)));
#else
	switch (left) {
	case 7: b |= ((u64)end[6]) << 48;
	case 6: b |= ((u64)end[5]) << 40;
	case 5: b |= ((u64)end[4]) << 32;
	case 4: b |= get_unaligned_le32(end); break;
	case 3: b |= ((u64)end[2]) << 16;
	case 2: b |= get_unaligned_le16(end); break;
	case 1: b |= end[0];
	}
#endif
	POSTAMBLE
}
EXPORT_SYMBOL(__siphash_unaligned);
#endif

/**
 * siphash_1u64 - compute 64-bit siphash PRF value of a u64
 * @first: first u64
 * @key: the siphash key
 */
u64 siphash_1u64(const u64 first, const siphash_key_t *key)
{
	PREAMBLE(8)
	v3 ^= first;
	SIPROUND;
	SIPROUND;
	v0 ^= first;
	POSTAMBLE
}
EXPORT_SYMBOL(siphash_1u64);

/**
 * siphash_2u64 - compute 64-bit siphash PRF value of 2 u64
 * @first: first u64
 * @second: second u64
 * @key: the siphash key
 */
u64 siphash_2u64(const u64 first, const u64 second, const siphash_key_t *key)
{
	PREAMBLE(16)
	v3 ^= first;
	SIPROUND;
	SIPROUND;
	v0 ^= first;
	v3 ^= second;
	SIPROUND;
	SIPROUND;
	v0 ^= second;
	POSTAMBLE
}
EXPORT_SYMBOL(siphash_2u64);

/**
 * siphash_3u64 - compute 64-bit siphash PRF value of 3 u64
 * @first: first u64
 * @second: second u64
 * @third: third u64
 * @key: the siphash key
 */
u64 siphash_3u64(const u64 first, const u64 second, const u64 third,
		 const siphash_key_t *key)
{
	PREAMBLE(24)
	v3 ^= first;
	SIPROUND;
	SIPROUND;
	v0 ^= first;
	v3 ^= second;
	SIPROUND;
	SIPROUND;
	v0 ^= second;
	v3 ^= third;
	SIPROUND;
	SIPROUND;
	v0 ^= third;
	POSTAMBLE
}
EXPORT_SYMBOL(siphash_3u64);

/**
 * siphash_4u64 - compute 64-bit siphash PRF value of 4 u64
 * @first: first u64
 * @second: second u64
 * @third: third u64
 * @forth: forth u64
 * @key: the siphash key
 */
u64 siphash_4u64(const u64 first, const u64 second, const u64 third,
		 const u64 forth, const siphash_key_t *key)
{
	PREAMBLE(32)
	v3 ^= first;
	SIPROUND;
	SIPROUND;
	v0 ^= first;
	v3 ^= second;
	SIPROUND;
	SIPROUND;
	v0 ^= second;
	v3 ^= third;
	SIPROUND;
	SIPROUND;
	v0 ^= third;
	v3 ^= forth;
	SIPROUND;
	SIPROUND;
	v0 ^= forth;
	POSTAMBLE
}
EXPORT_SYMBOL(siphash_4u64);

u64 siphash_1u32(const u32 first, const siphash_key_t *key)
{
	PREAMBLE(4)
	b |= first;
	POSTAMBLE
}
EXPORT_SYMBOL(siphash_1u32);

u64 siphash_3u32(const u32 first, const u32 second, const u32 third,
		 const siphash_key_t *key)
{
	u64 combined = (u64)second << 32 | first;
	PREAMBLE(12)
	v3 ^= combined;
	SIPROUND;
	SIPROUND;
	v0 ^= combined;
	b |= third;
	POSTAMBLE
}
EXPORT_SYMBOL(siphash_3u32);