release/src/router/nettle/umac-l2.c

   1 /* umac-l2.c
   2  */
   3
   4 /* nettle, low-level cryptographics library
   5  *
   6  * Copyright (C) 2013 Niels Möller
   7  *
   8  * The nettle library is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU Lesser General Public License as published by
  10  * the Free Software Foundation; either version 2.1 of the License, or (at your
  11  * option) any later version.
  12  *
  13  * The nettle library is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  16  * License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with the nettle library; see the file COPYING.LIB.  If not, write to
  20  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  21  * MA 02111-1301, USA.
  22  */
  23
  24 #if HAVE_CONFIG_H
  25 # include "config.h"
  26 #endif
  27
  28 #include <assert.h>
  29 #include <string.h>
  30
  31 #include "umac.h"
  32
  33 #include "macros.h"
  34
  35 /* Same mask applied to low and high halves */
  36 #define KEY_MASK 0x01ffffffUL
  37
  38 #if WORDS_BIGENDIAN
  39 #define BE_SWAP32(x) x
  40 #else
  41 #define BE_SWAP32(x)                            \
  42   ((ROTL32(8,  x) & 0x00FF00FFUL) |             \
  43    (ROTL32(24, x) & 0xFF00FF00UL))
  44 #endif
  45
  46 void
  47 _umac_l2_init (unsigned size, uint32_t *k)
  48 {
  49   unsigned i;
  50   for (i = 0; i < size; i++)
  51     {
  52       uint32_t w = k[i];
  53       w = BE_SWAP32 (w);
  54       k[i] = w & KEY_MASK;
  55     }
  56 }
  57
  58 void
  59 _umac_l2(const uint32_t *key, uint64_t *state, unsigned n,
  60          uint64_t count, const uint64_t *m)
  61 {
  62   uint64_t *prev = state + 2*n;
  63   unsigned i;
  64
  65   if (count == 0)
  66     memcpy (prev, m, n * sizeof(*m));
  67   else if (count == 1)
  68     for (i = 0; i < n; i++, key += 6)
  69       {
  70         uint64_t y = _umac_poly64 (key[0], key[1], 1, prev[i]);
  71         state[2*i+1] = _umac_poly64 (key[0], key[1], y, m[i]);
  72       }
  73   else if (count < UMAC_POLY64_BLOCKS)
  74     for (i = 0; i < n; i++, key += 6)
  75       state[2*i+1] = _umac_poly64 (key[0], key[1], state[2*i+1], m[i]);
  76   else if (count % 2 == 0)
  77     {
  78       if (count == UMAC_POLY64_BLOCKS)
  79         for (i = 0, key += 2; i < n; i++, key += 6)
  80           {
  81             uint64_t y = state[2*i+1];
  82             if (y >= UMAC_P64)
  83               y -= UMAC_P64;
  84             state[2*i] = 0;
  85             state[2*i+1] = 1;
  86
  87             _umac_poly128 (key, state + 2*i, 0, y);
  88           }
  89       memcpy (prev, m, n * sizeof(*m));
  90     }
  91   else
  92     for (i = 0, key += 2; i < n; i++, key += 6)
  93       _umac_poly128 (key, state + 2*i, prev[i], m[i]);
  94 }
  95
  96 void
  97 _umac_l2_final(const uint32_t *key, uint64_t *state, unsigned n,
  98                uint64_t count)
  99 {
 100   uint64_t *prev = state + 2*n;
 101   unsigned i;
 102
 103   assert (count > 0);
 104   if (count == 1)
 105     for (i = 0; i < n; i++)
 106       {
 107         *state++ = 0;
 108         *state++ = *prev++;
 109       }
 110   else if (count <= UMAC_POLY64_BLOCKS)
 111     for (i = 0; i < n; i++)
 112       {
 113         uint64_t y;
 114         *state++ = 0;
 115
 116         y = *state;
 117         if (y >= UMAC_P64)
 118           y -= UMAC_P64;
 119         *state++ = y;
 120       }
 121   else
 122     {
 123       uint64_t pad = (uint64_t) 1 << 63;
 124       if (count % 2 == 1)
 125         for (i = 0, key += 2; i < n; i++, key += 6)
 126           _umac_poly128 (key, state + 2*i, prev[i], pad);
 127       else
 128         for (i = 0, key += 2; i < n; i++, key += 6)
 129           _umac_poly128 (key, state + 2*i, pad, 0);
 130
 131       for (i = 0; i < n; i++, state += 2)
 132         {
 133           uint64_t yh, yl;
 134
 135           yh = state[0];
 136           yl = state[1];
 137           if (yh == UMAC_P128_HI && yl >= UMAC_P128_LO)
 138             {
 139               state[0] = 0;
 140               state[1] = yl -= UMAC_P128_LO;
 141             }
 142         }
 143     }
 144 }