_ Git - BearSSL/blob - src/config.h

   1 /*
   2  * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 #ifndef CONFIG_H__
  26 #define CONFIG_H__
  27
  28 /*
  29  * This file contains compile-time flags that can override the
  30  * autodetection performed in relevant files. Each flag is a macro; it
  31  * deactivates the feature if defined to 0, activates it if defined to a
  32  * non-zero integer (normally 1). If the macro is not defined, then
  33  * autodetection applies.
  34  */
  35
  36 /*
  37  * When BR_64 is enabled, 64-bit integer types are assumed to be
  38  * efficient (i.e. the architecture has 64-bit registers and can
  39  * do 64-bit operations as fast as 32-bit operations).
  40  *
  41 #define BR_64   1
  42  */
  43
  44 /*
  45  * When BR_SLOW_MUL is enabled, multiplications are assumed to be
  46  * substantially slow with regards to other integer operations, thus
  47  * making it worth to make more operations for a given task if it allows
  48  * using less multiplications.
  49  *
  50 #define BR_SLOW_MUL   1
  51  */
  52
  53 /*
  54  * When BR_SLOW_MUL15 is enabled, short multplications (on 15-bit words)
  55  * are assumed to be substantially slow with regards to other integer
  56  * operations, thus making it worth to make more integer operations if
  57  * it allows using less multiplications.
  58  *
  59 #define BR_SLOW_MUL15   1
  60  */
  61
  62 /*
  63  * When BR_CT_MUL31 is enabled, multiplications of 31-bit values (used
  64  * in the "i31" big integer implementation) use an alternate implementation
  65  * which is slower and larger than the normal multiplication, but should
  66  * ensure constant-time multiplications even on architectures where the
  67  * multiplication opcode takes a variable number of cycles to complete.
  68  *
  69 #define BR_CT_MUL31   1
  70  */
  71
  72 /*
  73  * When BR_CT_MUL15 is enabled, multiplications of 15-bit values (held
  74  * in 32-bit words) use an alternate implementation which is slower and
  75  * larger than the normal multiplication, but should ensure
  76  * constant-time multiplications on most/all architectures where the
  77  * basic multiplication is not constant-time.
  78 #define BR_CT_MUL15   1
  79  */
  80
  81 /*
  82  * When BR_NO_ARITH_SHIFT is enabled, arithmetic right shifts (with sign
  83  * extension) are performed with a sequence of operations which is bigger
  84  * and slower than a simple right shift on a signed value. This avoids
  85  * relying on an implementation-defined behaviour. However, most if not
  86  * all C compilers use sign extension for right shifts on signed values,
  87  * so this alternate macro is disabled by default.
  88 #define BR_NO_ARITH_SHIFT   1
  89  */
  90
  91 /*
  92  * When BR_USE_URANDOM is enabled, the SSL engine will use /dev/urandom
  93  * to automatically obtain quality randomness for seedings its internal
  94  * PRNG.
  95  *
  96 #define BR_USE_URANDOM   1
  97  */
  98
  99 /*
 100  * When BR_USE_WIN32_RAND is enabled, the SSL engine will use the Win32
 101  * (CryptoAPI) functions (CryptAcquireContext(), CryptGenRandom()...) to
 102  * automatically obtain quality randomness for seedings its internal PRNG.
 103  *
 104  * Note: if both BR_USE_URANDOM and BR_USE_WIN32_RAND are defined, the
 105  * former takes precedence.
 106  *
 107 #define BR_USE_WIN32_RAND   1
 108  */
 109
 110 /*
 111  * When BR_USE_UNIX_TIME is enabled, the X.509 validation engine obtains
 112  * the current time from the OS by calling time(), and assuming that the
 113  * returned value (a 'time_t') is an integer that counts time in seconds
 114  * since the Unix Epoch (Jan 1st, 1970, 00:00 UTC).
 115  *
 116 #define BR_USE_UNIX_TIME   1
 117  */
 118
 119 /*
 120  * When BR_USE_WIN32_TIME is enabled, the X.509 validation engine obtains
 121  * the current time from the OS by calling the Win32 function
 122  * GetSystemTimeAsFileTime().
 123  *
 124  * Note: if both BR_USE_UNIX_TIME and BR_USE_WIN32_TIME are defined, the
 125  * former takes precedence.
 126  *
 127 #define BR_USE_WIN32_TIME   1
 128  */
 129
 130 #endif