Line data    Source code

       1             : /*
       2             :  * Copyright (c) 2022 Rubicon Communications, LLC.
       3             :  * Licensed under the Apache License, Version 2.0 (the "License");
       4             :  * you may not use this file except in compliance with the License.
       5             :  * You may obtain a copy of the License at:
       6             :  *
       7             :  *     http://www.apache.org/licenses/LICENSE-2.0
       8             :  *
       9             :  * Unless required by applicable law or agreed to in writing, software
      10             :  * distributed under the License is distributed on an "AS IS" BASIS,
      11             :  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             :  * See the License for the specific language governing permissions and
      13             :  * limitations under the License.
      14             :  */
      15             : 
      16             : /*
      17             :  * chacha-merged.c version 20080118
      18             :  * D. J. Bernstein
      19             :  * Public domain.
      20             :  */
      21             : 
      22             : #ifndef __included_wg_hchacha20_h__
      23             : #define __included_wg_hchacha20_h__
      24             : 
      25             : #include <vlib/vlib.h>
      26             : 
      27             : /* clang-format off */
      28             : #define U32C(v) (v##U)
      29             : #define U32V(v) ((u32)(v) & U32C(0xFFFFFFFF))
      30             : 
      31             : #define ROTL32(v, n) \
      32             :   (U32V((v) << (n)) | ((v) >> (32 - (n))))
      33             : 
      34             : #define U8TO32_LITTLE(p) \
      35             :   (((u32)((p)[0])      ) | \
      36             :    ((u32)((p)[1]) <<  8) | \
      37             :    ((u32)((p)[2]) << 16) | \
      38             :    ((u32)((p)[3]) << 24))
      39             : 
      40             : #define ROTATE(v,c) (ROTL32(v,c))
      41             : #define XOR(v,w) ((v) ^ (w))
      42             : #define PLUS(v,w) (U32V((v) + (w)))
      43             : 
      44             : #define QUARTERROUND(a,b,c,d) \
      45             :   a = PLUS(a,b); d = ROTATE(XOR(d,a),16); \
      46             :   c = PLUS(c,d); b = ROTATE(XOR(b,c),12); \
      47             :   a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \
      48             :   c = PLUS(c,d); b = ROTATE(XOR(b,c), 7);
      49             : /* clang-format on */
      50             : 
      51             : static const char sigma[16] = "expand 32-byte k";
      52             : 
      53             : static inline void
      54          44 : hchacha20 (u32 derived_key[8], const u8 nonce[16], const u8 key[32])
      55             : {
      56             :   int i;
      57          44 :   u32 x[] = { U8TO32_LITTLE (sigma + 0), U8TO32_LITTLE (sigma + 4),
      58          44 :               U8TO32_LITTLE (sigma + 8), U8TO32_LITTLE (sigma + 12),
      59          44 :               U8TO32_LITTLE (key + 0),   U8TO32_LITTLE (key + 4),
      60          44 :               U8TO32_LITTLE (key + 8),   U8TO32_LITTLE (key + 12),
      61          44 :               U8TO32_LITTLE (key + 16),  U8TO32_LITTLE (key + 20),
      62          44 :               U8TO32_LITTLE (key + 24),  U8TO32_LITTLE (key + 28),
      63          44 :               U8TO32_LITTLE (nonce + 0), U8TO32_LITTLE (nonce + 4),
      64          44 :               U8TO32_LITTLE (nonce + 8), U8TO32_LITTLE (nonce + 12) };
      65             : 
      66         484 :   for (i = 20; i > 0; i -= 2)
      67             :     {
      68         440 :       QUARTERROUND (x[0], x[4], x[8], x[12])
      69         440 :       QUARTERROUND (x[1], x[5], x[9], x[13])
      70         440 :       QUARTERROUND (x[2], x[6], x[10], x[14])
      71         440 :       QUARTERROUND (x[3], x[7], x[11], x[15])
      72         440 :       QUARTERROUND (x[0], x[5], x[10], x[15])
      73         440 :       QUARTERROUND (x[1], x[6], x[11], x[12])
      74         440 :       QUARTERROUND (x[2], x[7], x[8], x[13])
      75         440 :       QUARTERROUND (x[3], x[4], x[9], x[14])
      76             :     }
      77             : 
      78          44 :   clib_memcpy (derived_key + 0, x + 0, sizeof (u32) * 4);
      79          44 :   clib_memcpy (derived_key + 4, x + 12, sizeof (u32) * 4);
      80          44 : }
      81             : 
      82             : #endif /* __included_wg_hchacha20_h__ */
      83             : 
      84             : /*
      85             :  * fd.io coding-style-patch-verification: ON
      86             :  *
      87             :  * Local Variables:
      88             :  * eval: (c-set-style "gnu")
      89             :  * End:
      90             :  */