Tor  0.4.6.0-alpha-dev
csiphash.c
1 /* <MIT License>
2  Copyright (c) 2013-2014 Marek Majkowski <marek@popcount.org>
3 
4  Permission is hereby granted, free of charge, to any person obtaining a copy
5  of this software and associated documentation files (the "Software"), to deal
6  in the Software without restriction, including without limitation the rights
7  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8  copies of the Software, and to permit persons to whom the Software is
9  furnished to do so, subject to the following conditions:
10 
11  The above copyright notice and this permission notice shall be included in
12  all copies or substantial portions of the Software.
13 
14  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20  THE SOFTWARE.
21  </MIT License>
22 
23  Original location:
24  https://github.com/majek/csiphash/
25 
26  Solution inspired by code from:
27  Samuel Neves (supercop/crypto_auth/siphash24/little)
28  djb (supercop/crypto_auth/siphash24/little2)
29  Jean-Philippe Aumasson (https://131002.net/siphash/siphash24.c)
30 */
31 
32 #include "lib/cc/torint.h"
33 #include "lib/err/torerr.h"
34 
35 #include "ext/siphash.h"
36 #include <string.h>
37 #include <stdlib.h>
38 #include "ext/byteorder.h"
39 
40 #define ROTATE(x, b) (uint64_t)( ((x) << (b)) | ( (x) >> (64 - (b))) )
41 
42 #define HALF_ROUND(a,b,c,d,s,t) \
43  a += b; c += d; \
44  b = ROTATE(b, s) ^ a; \
45  d = ROTATE(d, t) ^ c; \
46  a = ROTATE(a, 32);
47 
48 #define DOUBLE_ROUND(v0,v1,v2,v3) \
49  HALF_ROUND(v0,v1,v2,v3,13,16); \
50  HALF_ROUND(v2,v1,v0,v3,17,21); \
51  HALF_ROUND(v0,v1,v2,v3,13,16); \
52  HALF_ROUND(v2,v1,v0,v3,17,21);
53 
54 #if 0
55 /* This does not seem to save very much runtime in the fast case, and it's
56  * potentially a big loss in the slow case where we're misaligned and we cross
57  * a cache line. */
58 #if (defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
59  defined(__x86_64) || defined(__x86_64__) || \
60  defined(_M_AMD64) || defined(_M_X64) || defined(__INTEL__))
61 # define UNALIGNED_OK 1
62 #endif
63 #endif
64 
65 uint64_t siphash24(const void *src, unsigned long src_sz, const struct sipkey *key) {
66  const uint8_t *m = src;
67  uint64_t k0 = key->k0;
68  uint64_t k1 = key->k1;
69  uint64_t last7 = (uint64_t)(src_sz & 0xff) << 56;
70  size_t i, blocks;
71 
72  uint64_t v0 = k0 ^ 0x736f6d6570736575ULL;
73  uint64_t v1 = k1 ^ 0x646f72616e646f6dULL;
74  uint64_t v2 = k0 ^ 0x6c7967656e657261ULL;
75  uint64_t v3 = k1 ^ 0x7465646279746573ULL;
76 
77  for (i = 0, blocks = (src_sz & ~7); i < blocks; i+= 8) {
78 #ifdef UNALIGNED_OK
79  uint64_t mi = _le64toh(*(m + i));
80 #else
81  uint64_t mi;
82  memcpy(&mi, m + i, 8);
83  mi = _le64toh(mi);
84 #endif
85  v3 ^= mi;
86  DOUBLE_ROUND(v0,v1,v2,v3);
87  v0 ^= mi;
88  }
89 
90 #ifdef __COVERITY__
91  {
92  uint64_t mi = 0;
93  memcpy(&mi, m+i, (src_sz-blocks));
94  last7 = _le64toh(mi) | (uint64_t)(src_sz & 0xff) << 56;
95  }
96 #else
97  switch (src_sz - blocks) {
98  case 7: last7 |= (uint64_t)m[i + 6] << 48; FALLTHROUGH;
99  case 6: last7 |= (uint64_t)m[i + 5] << 40; FALLTHROUGH;
100  case 5: last7 |= (uint64_t)m[i + 4] << 32; FALLTHROUGH;
101  case 4: last7 |= (uint64_t)m[i + 3] << 24; FALLTHROUGH;
102  case 3: last7 |= (uint64_t)m[i + 2] << 16; FALLTHROUGH;
103  case 2: last7 |= (uint64_t)m[i + 1] << 8; FALLTHROUGH;
104  case 1: last7 |= (uint64_t)m[i + 0] ; FALLTHROUGH;
105  case 0:
106  default:;
107  }
108 #endif
109  v3 ^= last7;
110  DOUBLE_ROUND(v0,v1,v2,v3);
111  v0 ^= last7;
112  v2 ^= 0xff;
113  DOUBLE_ROUND(v0,v1,v2,v3);
114  DOUBLE_ROUND(v0,v1,v2,v3);
115  return v0 ^ v1 ^ v2 ^ v3;
116 }
117 
118 
119 static int the_siphash_key_is_set = 0;
120 static struct sipkey the_siphash_key;
121 
122 uint64_t siphash24g(const void *src, unsigned long src_sz) {
123  raw_assert(the_siphash_key_is_set);
124  return siphash24(src, src_sz, &the_siphash_key);
125 }
126 
127 void siphash_set_global_key(const struct sipkey *key)
128 {
129  raw_assert(! the_siphash_key_is_set);
130  the_siphash_key.k0 = key->k0;
131  the_siphash_key.k1 = key->k1;
132  the_siphash_key_is_set = 1;
133 }
134 
135 void siphash_unset_global_key(void)
136 {
137  the_siphash_key_is_set = 0;
138  memset(&the_siphash_key, 0, sizeof(the_siphash_key));
139 }
sipkey
Definition: siphash.h:6
torint.h
Integer definitions used throughout Tor.
torerr.h
Headers for torerr.c.