src/ext/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/log/util_bug.h"
  34
  35 #include "siphash.h"
  36 #include <string.h>
  37 #include <stdlib.h>
  38 #include "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         switch (src_sz - blocks) {
  91                 case 7: last7 |= (uint64_t)m[i + 6] << 48; /* Falls through. */
  92                 case 6: last7 |= (uint64_t)m[i + 5] << 40; /* Falls through. */
  93                 case 5: last7 |= (uint64_t)m[i + 4] << 32; /* Falls through. */
  94                 case 4: last7 |= (uint64_t)m[i + 3] << 24; /* Falls through. */
  95                 case 3: last7 |= (uint64_t)m[i + 2] << 16; /* Falls through. */
  96                 case 2: last7 |= (uint64_t)m[i + 1] <<  8; /* Falls through. */
  97                 case 1: last7 |= (uint64_t)m[i + 0]      ; /* Falls through. */
  98                 case 0:
  99                 default:;
 100         }
 101         v3 ^= last7;
 102         DOUBLE_ROUND(v0,v1,v2,v3);
 103         v0 ^= last7;
 104         v2 ^= 0xff;
 105         DOUBLE_ROUND(v0,v1,v2,v3);
 106         DOUBLE_ROUND(v0,v1,v2,v3);
 107         return v0 ^ v1 ^ v2 ^ v3;
 108 }
 109
 110
 111 static int the_siphash_key_is_set = 0;
 112 static struct sipkey the_siphash_key;
 113
 114 uint64_t siphash24g(const void *src, unsigned long src_sz) {
 115         tor_assert(the_siphash_key_is_set);
 116         return siphash24(src, src_sz, &the_siphash_key);
 117 }
 118
 119 void siphash_set_global_key(const struct sipkey *key)
 120 {
 121         tor_assert(! the_siphash_key_is_set);
 122         the_siphash_key.k0 = key->k0;
 123         the_siphash_key.k1 = key->k1;
 124         the_siphash_key_is_set = 1;
 125 }
 126
 127 void siphash_unset_global_key(void)
 128 {
 129         the_siphash_key_is_set = 0;
 130         memset(&the_siphash_key, 0, sizeof(the_siphash_key));
 131 }