library/common.h

/**
 * \file common.h
 *
 * \brief Utility macros for internal use in the library
 */
/*
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

#ifndef MBEDTLS_LIBRARY_COMMON_H
#define MBEDTLS_LIBRARY_COMMON_H

#include "mbedtls/build_info.h"

#include <stdint.h>
#include <stddef.h>

/** Helper to define a function as static except when building invasive tests.
 *
 * If a function is only used inside its own source file and should be
 * declared `static` to allow the compiler to optimize for code size,
 * but that function has unit tests, define it with
 * ```
 * MBEDTLS_STATIC_TESTABLE int mbedtls_foo(...) { ... }
 * ```
 * and declare it in a header in the `library/` directory with
 * ```
 * #if defined(MBEDTLS_TEST_HOOKS)
 * int mbedtls_foo(...);
 * #endif
 * ```
 */
#if defined(MBEDTLS_TEST_HOOKS)
#define MBEDTLS_STATIC_TESTABLE
#else
#define MBEDTLS_STATIC_TESTABLE static
#endif

#if defined(MBEDTLS_TEST_HOOKS)
extern void (*mbedtls_test_hook_test_fail)( const char * test, int line, const char * file );
#define MBEDTLS_TEST_HOOK_TEST_ASSERT( TEST ) \
       do { \
            if( ( ! ( TEST ) ) && ( ( *mbedtls_test_hook_test_fail ) != NULL ) ) \
            { \
              ( *mbedtls_test_hook_test_fail )( #TEST, __LINE__, __FILE__ ); \
            } \
    } while( 0 )
#else
#define MBEDTLS_TEST_HOOK_TEST_ASSERT( TEST )
#endif /* defined(MBEDTLS_TEST_HOOKS) */

/** Allow library to access its structs' private members.
 *
 * Although structs defined in header files are publicly available,
 * their members are private and should not be accessed by the user.
 */
#define MBEDTLS_ALLOW_PRIVATE_ACCESS

/** Detect architectures where unaligned memory accesses are safe and performant.
 *
 * This list is incomplete.
 */
#if defined(__i386__) || defined(__amd64__) || defined( __x86_64__) \
    || defined(__ARM_FEATURE_UNALIGNED) \
    || defined(__aarch64__) \
    || defined(__ARM_ARCH_8__) || defined(__ARM_ARCH_8A__) || defined(__ARM_ARCH_8M__) \
    || defined(__ARM_ARCH_7A__)
#define MBEDTLS_ALLOW_UNALIGNED_ACCESS
#endif

/** Byte Reading Macros
 *
 * Given a multi-byte integer \p x, MBEDTLS_BYTE_n retrieves the n-th
 * byte from x, where byte 0 is the least significant byte.
 */
#define MBEDTLS_BYTE_0( x ) ( (uint8_t) (   ( x )         & 0xff ) )
#define MBEDTLS_BYTE_1( x ) ( (uint8_t) ( ( ( x ) >> 8  ) & 0xff ) )
#define MBEDTLS_BYTE_2( x ) ( (uint8_t) ( ( ( x ) >> 16 ) & 0xff ) )
#define MBEDTLS_BYTE_3( x ) ( (uint8_t) ( ( ( x ) >> 24 ) & 0xff ) )
#define MBEDTLS_BYTE_4( x ) ( (uint8_t) ( ( ( x ) >> 32 ) & 0xff ) )
#define MBEDTLS_BYTE_5( x ) ( (uint8_t) ( ( ( x ) >> 40 ) & 0xff ) )
#define MBEDTLS_BYTE_6( x ) ( (uint8_t) ( ( ( x ) >> 48 ) & 0xff ) )
#define MBEDTLS_BYTE_7( x ) ( (uint8_t) ( ( ( x ) >> 56 ) & 0xff ) )

/**
 * Get the unsigned 32 bits integer corresponding to four bytes in
 * big-endian order (MSB first).
 *
 * \param   data    Base address of the memory to get the four bytes from.
 * \param   offset  Offset from \p data of the first and most significant
 *                  byte of the four bytes to build the 32 bits unsigned
 *                  integer from.
 */
#ifndef MBEDTLS_GET_UINT32_BE
#define MBEDTLS_GET_UINT32_BE( data , offset )                  \
    (                                                           \
          ( (uint32_t) ( data )[( offset )    ] << 24 )         \
        | ( (uint32_t) ( data )[( offset ) + 1] << 16 )         \
        | ( (uint32_t) ( data )[( offset ) + 2] <<  8 )         \
        | ( (uint32_t) ( data )[( offset ) + 3]       )         \
    )
#endif

/**
 * Put in memory a 32 bits unsigned integer in big-endian order.
 *
 * \param   n       32 bits unsigned integer to put in memory.
 * \param   data    Base address of the memory where to put the 32
 *                  bits unsigned integer in.
 * \param   offset  Offset from \p data where to put the most significant
 *                  byte of the 32 bits unsigned integer \p n.
 */
#ifndef MBEDTLS_PUT_UINT32_BE
#define MBEDTLS_PUT_UINT32_BE( n, data, offset )                \
{                                                               \
    ( data )[( offset )    ] = MBEDTLS_BYTE_3( n );             \
    ( data )[( offset ) + 1] = MBEDTLS_BYTE_2( n );             \
    ( data )[( offset ) + 2] = MBEDTLS_BYTE_1( n );             \
    ( data )[( offset ) + 3] = MBEDTLS_BYTE_0( n );             \
}
#endif

/**
 * Get the unsigned 32 bits integer corresponding to four bytes in
 * little-endian order (LSB first).
 *
 * \param   data    Base address of the memory to get the four bytes from.
 * \param   offset  Offset from \p data of the first and least significant
 *                  byte of the four bytes to build the 32 bits unsigned
 *                  integer from.
 */
#ifndef MBEDTLS_GET_UINT32_LE
#define MBEDTLS_GET_UINT32_LE( data, offset )                   \
    (                                                           \
          ( (uint32_t) ( data )[( offset )    ]       )         \
        | ( (uint32_t) ( data )[( offset ) + 1] <<  8 )         \
        | ( (uint32_t) ( data )[( offset ) + 2] << 16 )         \
        | ( (uint32_t) ( data )[( offset ) + 3] << 24 )         \
    )
#endif

/**
 * Put in memory a 32 bits unsigned integer in little-endian order.
 *
 * \param   n       32 bits unsigned integer to put in memory.
 * \param   data    Base address of the memory where to put the 32
 *                  bits unsigned integer in.
 * \param   offset  Offset from \p data where to put the least significant
 *                  byte of the 32 bits unsigned integer \p n.
 */
#ifndef MBEDTLS_PUT_UINT32_LE
#define MBEDTLS_PUT_UINT32_LE( n, data, offset )                \
{                                                               \
    ( data )[( offset )    ] = MBEDTLS_BYTE_0( n );             \
    ( data )[( offset ) + 1] = MBEDTLS_BYTE_1( n );             \
    ( data )[( offset ) + 2] = MBEDTLS_BYTE_2( n );             \
    ( data )[( offset ) + 3] = MBEDTLS_BYTE_3( n );             \
}
#endif

/**
 * Get the unsigned 16 bits integer corresponding to two bytes in
 * little-endian order (LSB first).
 *
 * \param   data    Base address of the memory to get the two bytes from.
 * \param   offset  Offset from \p data of the first and least significant
 *                  byte of the two bytes to build the 16 bits unsigned
 *                  integer from.
 */
#ifndef MBEDTLS_GET_UINT16_LE
#define MBEDTLS_GET_UINT16_LE( data, offset )                   \
    (                                                           \
          ( (uint16_t) ( data )[( offset )    ]       )         \
        | ( (uint16_t) ( data )[( offset ) + 1] <<  8 )         \
    )
#endif

/**
 * Put in memory a 16 bits unsigned integer in little-endian order.
 *
 * \param   n       16 bits unsigned integer to put in memory.
 * \param   data    Base address of the memory where to put the 16
 *                  bits unsigned integer in.
 * \param   offset  Offset from \p data where to put the least significant
 *                  byte of the 16 bits unsigned integer \p n.
 */
#ifndef MBEDTLS_PUT_UINT16_LE
#define MBEDTLS_PUT_UINT16_LE( n, data, offset )                \
{                                                               \
    ( data )[( offset )    ] = MBEDTLS_BYTE_0( n );             \
    ( data )[( offset ) + 1] = MBEDTLS_BYTE_1( n );             \
}
#endif

/**
 * Get the unsigned 16 bits integer corresponding to two bytes in
 * big-endian order (MSB first).
 *
 * \param   data    Base address of the memory to get the two bytes from.
 * \param   offset  Offset from \p data of the first and most significant
 *                  byte of the two bytes to build the 16 bits unsigned
 *                  integer from.
 */
#ifndef MBEDTLS_GET_UINT16_BE
#define MBEDTLS_GET_UINT16_BE( data, offset )                   \
    (                                                           \
          ( (uint16_t) ( data )[( offset )    ] << 8 )          \
        | ( (uint16_t) ( data )[( offset ) + 1]      )          \
    )
#endif

/**
 * Put in memory a 16 bits unsigned integer in big-endian order.
 *
 * \param   n       16 bits unsigned integer to put in memory.
 * \param   data    Base address of the memory where to put the 16
 *                  bits unsigned integer in.
 * \param   offset  Offset from \p data where to put the most significant
 *                  byte of the 16 bits unsigned integer \p n.
 */
#ifndef MBEDTLS_PUT_UINT16_BE
#define MBEDTLS_PUT_UINT16_BE( n, data, offset )                \
{                                                               \
    ( data )[( offset )    ] = MBEDTLS_BYTE_1( n );             \
    ( data )[( offset ) + 1] = MBEDTLS_BYTE_0( n );             \
}
#endif

/**
 * Get the unsigned 24 bits integer corresponding to three bytes in
 * big-endian order (MSB first).
 *
 * \param   data    Base address of the memory to get the three bytes from.
 * \param   offset  Offset from \p data of the first and most significant
 *                  byte of the three bytes to build the 24 bits unsigned
 *                  integer from.
 */
#ifndef MBEDTLS_GET_UINT24_BE
#define MBEDTLS_GET_UINT24_BE( data , offset )                  \
    (                                                           \
          ( (uint32_t) ( data )[( offset )    ] << 16 )         \
        | ( (uint32_t) ( data )[( offset ) + 1] << 8  )         \
        | ( (uint32_t) ( data )[( offset ) + 2]       )         \
    )
#endif

/**
 * Put in memory a 24 bits unsigned integer in big-endian order.
 *
 * \param   n       24 bits unsigned integer to put in memory.
 * \param   data    Base address of the memory where to put the 24
 *                  bits unsigned integer in.
 * \param   offset  Offset from \p data where to put the most significant
 *                  byte of the 24 bits unsigned integer \p n.
 */
#ifndef MBEDTLS_PUT_UINT24_BE
#define MBEDTLS_PUT_UINT24_BE( n, data, offset )                \
{                                                               \
    ( data )[( offset )    ] = MBEDTLS_BYTE_2( n );             \
    ( data )[( offset ) + 1] = MBEDTLS_BYTE_1( n );             \
    ( data )[( offset ) + 2] = MBEDTLS_BYTE_0( n );             \
}
#endif

/**
 * Get the unsigned 24 bits integer corresponding to three bytes in
 * little-endian order (LSB first).
 *
 * \param   data    Base address of the memory to get the three bytes from.
 * \param   offset  Offset from \p data of the first and least significant
 *                  byte of the three bytes to build the 24 bits unsigned
 *                  integer from.
 */
#ifndef MBEDTLS_GET_UINT24_LE
#define MBEDTLS_GET_UINT24_LE( data, offset )                   \
    (                                                           \
          ( (uint32_t) ( data )[( offset )    ]       )         \
        | ( (uint32_t) ( data )[( offset ) + 1] <<  8 )         \
        | ( (uint32_t) ( data )[( offset ) + 2] << 16 )         \
    )
#endif

/**
 * Put in memory a 24 bits unsigned integer in little-endian order.
 *
 * \param   n       24 bits unsigned integer to put in memory.
 * \param   data    Base address of the memory where to put the 24
 *                  bits unsigned integer in.
 * \param   offset  Offset from \p data where to put the least significant
 *                  byte of the 24 bits unsigned integer \p n.
 */
#ifndef MBEDTLS_PUT_UINT24_LE
#define MBEDTLS_PUT_UINT24_LE( n, data, offset )                \
{                                                               \
    ( data )[( offset )    ] = MBEDTLS_BYTE_0( n );             \
    ( data )[( offset ) + 1] = MBEDTLS_BYTE_1( n );             \
    ( data )[( offset ) + 2] = MBEDTLS_BYTE_2( n );             \
}
#endif

/**
 * Get the unsigned 64 bits integer corresponding to eight bytes in
 * big-endian order (MSB first).
 *
 * \param   data    Base address of the memory to get the eight bytes from.
 * \param   offset  Offset from \p data of the first and most significant
 *                  byte of the eight bytes to build the 64 bits unsigned
 *                  integer from.
 */
#ifndef MBEDTLS_GET_UINT64_BE
#define MBEDTLS_GET_UINT64_BE( data, offset )                   \
    (                                                           \
          ( (uint64_t) ( data )[( offset )    ] << 56 )         \
        | ( (uint64_t) ( data )[( offset ) + 1] << 48 )         \
        | ( (uint64_t) ( data )[( offset ) + 2] << 40 )         \
        | ( (uint64_t) ( data )[( offset ) + 3] << 32 )         \
        | ( (uint64_t) ( data )[( offset ) + 4] << 24 )         \
        | ( (uint64_t) ( data )[( offset ) + 5] << 16 )         \
        | ( (uint64_t) ( data )[( offset ) + 6] <<  8 )         \
        | ( (uint64_t) ( data )[( offset ) + 7]       )         \
    )
#endif

/**
 * Put in memory a 64 bits unsigned integer in big-endian order.
 *
 * \param   n       64 bits unsigned integer to put in memory.
 * \param   data    Base address of the memory where to put the 64
 *                  bits unsigned integer in.
 * \param   offset  Offset from \p data where to put the most significant
 *                  byte of the 64 bits unsigned integer \p n.
 */
#ifndef MBEDTLS_PUT_UINT64_BE
#define MBEDTLS_PUT_UINT64_BE( n, data, offset )                \
{                                                               \
    ( data )[( offset )    ] = MBEDTLS_BYTE_7( n );             \
    ( data )[( offset ) + 1] = MBEDTLS_BYTE_6( n );             \
    ( data )[( offset ) + 2] = MBEDTLS_BYTE_5( n );             \
    ( data )[( offset ) + 3] = MBEDTLS_BYTE_4( n );             \
    ( data )[( offset ) + 4] = MBEDTLS_BYTE_3( n );             \
    ( data )[( offset ) + 5] = MBEDTLS_BYTE_2( n );             \
    ( data )[( offset ) + 6] = MBEDTLS_BYTE_1( n );             \
    ( data )[( offset ) + 7] = MBEDTLS_BYTE_0( n );             \
}
#endif

/**
 * Get the unsigned 64 bits integer corresponding to eight bytes in
 * little-endian order (LSB first).
 *
 * \param   data    Base address of the memory to get the eight bytes from.
 * \param   offset  Offset from \p data of the first and least significant
 *                  byte of the eight bytes to build the 64 bits unsigned
 *                  integer from.
 */
#ifndef MBEDTLS_GET_UINT64_LE
#define MBEDTLS_GET_UINT64_LE( data, offset )                   \
    (                                                           \
          ( (uint64_t) ( data )[( offset ) + 7] << 56 )         \
        | ( (uint64_t) ( data )[( offset ) + 6] << 48 )         \
        | ( (uint64_t) ( data )[( offset ) + 5] << 40 )         \
        | ( (uint64_t) ( data )[( offset ) + 4] << 32 )         \
        | ( (uint64_t) ( data )[( offset ) + 3] << 24 )         \
        | ( (uint64_t) ( data )[( offset ) + 2] << 16 )         \
        | ( (uint64_t) ( data )[( offset ) + 1] <<  8 )         \
        | ( (uint64_t) ( data )[( offset )    ]       )         \
    )
#endif

/**
 * Put in memory a 64 bits unsigned integer in little-endian order.
 *
 * \param   n       64 bits unsigned integer to put in memory.
 * \param   data    Base address of the memory where to put the 64
 *                  bits unsigned integer in.
 * \param   offset  Offset from \p data where to put the least significant
 *                  byte of the 64 bits unsigned integer \p n.
 */
#ifndef MBEDTLS_PUT_UINT64_LE
#define MBEDTLS_PUT_UINT64_LE( n, data, offset )                \
{                                                               \
    ( data )[( offset )    ] = MBEDTLS_BYTE_0( n );             \
    ( data )[( offset ) + 1] = MBEDTLS_BYTE_1( n );             \
    ( data )[( offset ) + 2] = MBEDTLS_BYTE_2( n );             \
    ( data )[( offset ) + 3] = MBEDTLS_BYTE_3( n );             \
    ( data )[( offset ) + 4] = MBEDTLS_BYTE_4( n );             \
    ( data )[( offset ) + 5] = MBEDTLS_BYTE_5( n );             \
    ( data )[( offset ) + 6] = MBEDTLS_BYTE_6( n );             \
    ( data )[( offset ) + 7] = MBEDTLS_BYTE_7( n );             \
}
#endif

/**
 * Perform a fast block XOR operation, such that
 * r[i] = a[i] ^ b[i] where 0 <= i < n
 *
 * \param   r Pointer to result (buffer of at least \p n bytes). \p r
 *            may be equal to either \p a or \p b, but behaviour when
 *            it overlaps in other ways is undefined.
 * \param   a Pointer to input (buffer of at least \p n bytes)
 * \param   b Pointer to input (buffer of at least \p n bytes)
 * \param   n Number of bytes to process.
 */
static inline void mbedtls_xor( unsigned char *r, unsigned char const *a, unsigned char const *b, size_t n )
{
#if defined(MBEDTLS_ALLOW_UNALIGNED_ACCESS)
    uint32_t *a32 = (uint32_t *)a;
    uint32_t *b32 = (uint32_t *)b;
    uint32_t *r32 = (uint32_t *)r;
    for ( size_t i = 0; i < ( n >> 2 ); i++ )
    {
        r32[i] = a32[i] ^ b32[i];
    }
    for ( size_t i = n - ( n % 4 ) ; i < n; i++ )
    {
        r[i] = a[i] ^ b[i];
    }
#else
    for ( size_t i = 0; i < n; i++ )
    {
        r[i] = a[i] ^ b[i];
    }
#endif
}

/* Fix MSVC C99 compatible issue
 *      MSVC support __func__ from visual studio 2015( 1900 )
 *      Use MSVC predefine macro to avoid name check fail.
 */
#if (defined(_MSC_VER) && ( _MSC_VER <= 1900 ))
#define /*no-check-names*/ __func__ __FUNCTION__
#endif

#endif /* MBEDTLS_LIBRARY_COMMON_H */