/********************************************************************************/
/*										*/
/*	 		TPM to OpenSSL BigNum Shim Layer			*/
/*			     Written by Ken Goldman				*/
/*		       IBM Thomas J. Watson Research Center			*/
/*            $Id: TpmToOsslMath.h 1594 2020-03-26 22:15:48Z kgoldman $		*/
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/* B.2.2.1. TpmToOsslMath.h */
/* B.2.2.1.1. Introduction */
/* This file contains the structure definitions used for ECC in the LibTopCrypt() version of the
   code. These definitions would change, based on the library. The ECC-related structures that cross
   the TPM interface are defined in TpmTypes.h */

#ifndef MATH_LIB_DEFINED
#define MATH_LIB_DEFINED
#define MATH_LIB_OSSL
#include <openssl/evp.h>
#include <openssl/ec.h>

#define SYMMETRIC_ALIGNMENT RADIX_BYTES

#if OPENSSL_VERSION_NUMBER >= 0x10200000L
// Check the bignum_st definition in crypto/bn/bn_lcl.h and either update the
// version check or provide the new definition for this version.
#   error Untested OpenSSL version
#elif OPENSSL_VERSION_NUMBER >= 0x10100000L
// from crypto/bn/bn_lcl.h
struct bignum_st {
    BN_ULONG *d;
    int top;                    /* Index of last used d +1. */
    /* The next are internal book keeping for bn_expand. */
    int dmax;                   /* Size of the d array. */
    int neg;                    /* one if the number is negative */
    int flags;
};
#   define EC_POINT_get_affine_coordinates EC_POINT_get_affine_coordinates_GFp
#   define EC_POINT_set_affine_coordinates EC_POINT_set_affine_coordinates_GFp
#endif // OPENSSL_VERSION_NUMBER

#include <openssl/bn.h>

/* B.2.2.2.2. Macros and Defines */
/* Make sure that the library is using the correct size for a crypt word */

#if    defined THIRTY_TWO_BIT && (RADIX_BITS != 32)			\
    || ((defined SIXTY_FOUR_BIT_LONG || defined SIXTY_FOUR_BIT)		\
	&& (RADIX_BITS != 64))
#   error Ossl library is using different radix
#endif

/* Allocate a local BIGNUM value. For the allocation, a bigNum structure is created as is a local
   BIGNUM. The bigNum is initialized and then the BIGNUM is set to reference the local value. */

#define BIG_VAR(name, bits)						\
    BN_VAR(name##Bn, (bits));						\
    BIGNUM          _##name;						\
    BIGNUM          *name = BigInitialized(&_##name,			\
					   BnInit(name##Bn,		\
						  BYTES_TO_CRYPT_WORDS(sizeof(_##name##Bn.d))))

/* Allocate a BIGNUM and initialize with the values in a bigNum initializer */

#define BIG_INITIALIZED(name, initializer)				\
    BIGNUM           _##name;						\
    BIGNUM          *name = BigInitialized(&_##name, initializer)

typedef struct
{
    const ECC_CURVE_DATA    *C;     // the TPM curve values
    EC_GROUP                *G;     // group parameters
    BN_CTX                  *CTX;   // the context for the math (this might not be
    // the context in which the curve was created>;
} OSSL_CURVE_DATA;
typedef OSSL_CURVE_DATA      *bigCurve;
#define AccessCurveData(E)  ((E)->C)

#include "TpmToOsslSupport_fp.h"

#define OSSL_ENTER()     BN_CTX      *CTX = OsslContextEnter()
#define OSSL_LEAVE()     OsslContextLeave(CTX)

/* Start and end a context that spans multiple ECC functions. This is used so that the group for the
   curve can persist across multiple frames. */

#define CURVE_INITIALIZED(name, initializer)				\
    OSSL_CURVE_DATA     _##name;					\
    bigCurve            name =  BnCurveInitialize(&_##name, initializer)

#define CURVE_FREE(name)               BnCurveFree(name)

/* Start and end a local stack frame within the context of the curve frame */
#define ECC_ENTER()     BN_CTX         *CTX = OsslPushContext(E->CTX)
#define ECC_LEAVE()     OsslPopContext(CTX)
#define BN_NEW()        BnNewVariable(CTX)


/* This definition would change if there were something to report */
#define MathLibSimulationEnd()
#endif // MATH_LIB_DEFINED


