//====  Copyright (c) 2017 Advanced Micro Devices, Inc.  All rights reserved.
//
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//===----------------------------------------------------------------------===//

#ifndef secrng_h
#define secrng_h

#include <stdint.h>

#define SECRNG_SUCCESS 2
#define SECRNG_SUPPORTED 1
#define SECRNG_NOT_SUPPORTED -1
#define SECRNG_FAILURE -2
#define SECRNG_INVALID_INPUT -3

/*! \brief Checks support for RDRAND instruction
* This function checks if the target architecture supports RDRAND instruction
*
* \return Value indicating whether RDRAND is suuported or not. 1 - Success
*/
int is_RDRAND_supported();

/*! \brief Checks support for RDSEED instruction
* This function checks if the target architecture supports RDSEED instruction
*
* \return Value indicating whether RDSEED is suuported or not. 1 - Success
*/
int is_RDSEED_supported();

/*! \brief Returns a single 16-bit value using RDRAND
*
* This function invokes RDRAND instruction to fetch a single 16-bit value. On success,
* the value returned by RDRAND is written to rng_val. On failure, the function retries
* invoking RDRAND retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_val Pointer to memory to store the value returned by RDRAND
* \param retry_count Number of retry attempts
* \return success ot failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdrand16u(uint16_t* rng_val, unsigned int retry_count);

/*! \brief Returns a single 16-bit value using RDSEED
*
* This function invokes RDSEED instruction to fetch a single 16-bit value. On success,
* the value returned by RDSEED is written to rng_val. On failure, the function retries
* invoking RDSEED retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_val Pointer to memory to store the value returned by RDSEED
* \param retry_count Number of retry attempts
* \return success ot failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdseed16u(uint16_t* rng_val, unsigned int retry_count);

/*! \brief Returns a single 32-bit value using RDRAND
*
* This function invokes RDRAND instruction to fetch a single 32-bit value. On success,
* the value returned by RDRAND is written to rng_val. On failure, the function retries
* invoking RDRAND retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_val Pointer to memory to store the value returned by RDRAND
* \param retry_count Number of retry attempts
* \return success ot failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdrand32u(uint32_t* rng_val, unsigned int retry_count);

/*! \brief Returns a single 32-bit value using RDSEED
*
* This function invokes RDSEED instruction to fetch a single 32-bit value. On success,
* the value returned by RDSEED is written to rng_val. On failure, the function retries
* invoking RDSEED retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_val Pointer to memory to store the value returned by RDSEED
* \param retry_count Number of retry attempts
* \return success ot failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdseed32u(uint32_t* rng_val, unsigned int retry_count);

/*! \brief Returns a single 64-bit value using RDRAND
*
* This function invokes RDRAND instruction to fetch a single 64-bit value. On success,
* the value returned by RDRAND is written to rng_val. On failure, the function retries
* invoking RDRAND retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_val Pointer to memory to store the value returned by RDRAND
* \param retry_count Number of retry attempts
* \return success ot failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdrand64u(uint64_t* rng_val, unsigned int retry_count);

/*! \brief Returns a single 64-bit value using RDSEED
*
* This function invokes RDSEED instruction to fetch a single 64-bit value. On success,
* the value returned by RDSEED is written to rng_val. On failure, the function retries
* invoking RDSEED retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_val Pointer to memory to store the value returned by RDSEED
* \param retry_count Number of retry attempts
* \return success ot failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdseed64u(uint64_t* rng_val, unsigned int retry_count);

/*! \brief Returns an array of 32-bit values using RDRAND
*
* This function invokes RDRAND instruction N times to fetch an array of 32-bit values. On success,
* the values are written to rng_arr. On each failure, the function retries
* invoking RDRAND retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_arr Pointer to memory to store the values returned by RDRAND
* \param N Number of random values to return
* \param retry_count Number of retry attempts
* \return success or failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdrand32u_arr(uint32_t* rng_arr, unsigned int N, unsigned int retry_count);

/*! \brief Returns an array of 32-bit values using RDSEED
*
* This function invokes RDSEED instruction N times to fetch an array of 32-bit values. On success,
* the values are written to rng_arr. On each failure, the function retries
* invoking RDSEED retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_arr Pointer to memory to store the values returned by RDSEED
* \param N Number of random values to return
* \param retry_count Number of retry attempts
* \return success or failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdseed32u_arr(uint32_t* rng_arr, unsigned int N, unsigned int retry_count);

/*! \brief Returns an array of 64-bit values using RDRAND
*
* This function invokes RDRAND instruction N times to fetch an array of 64-bit values. On success,
* the values are written to rng_arr. On each failure, the function retries
* invoking RDRAND retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_arr Pointer to memory to store the values returned by RDRAND
* \param N Number of random values to return
* \param retry_count Number of retry attempts
* \return success or failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdrand64u_arr(uint64_t* rng_arr, unsigned int N, unsigned int retry_count);

/*! \brief Returns an array of 64-bit values using RDSEED
*
* This function invokes RDSEED instruction N times to fetch an array of 64-bit values. On success,
* the values are written to rng_arr. On each failure, the function retries
* invoking RDSEED retry_count times. Any failure after this, the function will return 
* error.
*
* \param rng_arr Pointer to memory to store the values returned by RDSEED
* \param N Number of random values to return
* \param retry_count Number of retry attempts
* \return success or failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdseed64u_arr(uint64_t* rng_arr, unsigned int N, unsigned int retry_count);

/*! \brief Returns an array of random bytes of the given size using RDRAND
*
* This function invokes RDRAND instruction multiple times to fetch an array of random bytes of
* given size. On success, the values are written to rng_arr. On failure, it returns error. 
*
* \param rng_arr Pointer to memory to store the random  bytes
* \param N Number of random bytes to return
* \param retry_count Number of retry attempts
* \return success or failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdrand_bytes_arr(unsigned char *rng_arr, unsigned int N, unsigned int retry_count);

/*! \brief Returns an array of random bytes of the given size using RDSEED
*
* This function invokes RDSEED instruction multiple times to fetch an array of random bytes of
* given size. On success, the values are written to rng_arr. On failure, it returns error. 
*
* \param rng_arr Pointer to memory to store the random  bytes
* \param N Number of random bytes to return
* \param retry_count Number of retry attempts
* \return success or failure status of function call: SECRNG_SUCCESS, SECRNG_FAILURE, SECRNG_NOTSUPPORTED
*/
int get_rdseed_bytes_arr(unsigned char *rng_arr, unsigned int N, unsigned int retry_count);

#endif