/* crypto/dh/dh.h */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *   notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *   must display the following acknowledgement:
 *   "This product includes cryptographic software written by
 *    Eric Young (eay@cryptsoft.com)"
 *   The word 'cryptographic' can be left out if the rouines from the library
 *   being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *   the apps directory (application code) you must include an acknowledgement:
 *   "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

module deimos.openssl.dh;

import deimos.openssl._d_util;

import deimos.openssl.evp; // Needed for EVP_PKEY_ALG_CTRL.

public import deimos.openssl.e_os2;

version (OPENSSL_NO_DH) {
  static assert(false, "DH is disabled.");
}

version(OPENSSL_NO_BIO) {} else {
public import deimos.openssl.bio;
}
public import deimos.openssl.ossl_typ;
version(OPENSSL_NO_DEPRECATED) {} else {
public import deimos.openssl.bn;
}

// #ifndef OPENSSL_DH_MAX_MODULUS_BITS
enum OPENSSL_DH_MAX_MODULUS_BITS = 10000;
// #endif

enum DH_FLAG_CACHE_MONT_P = 0x01;
enum DH_FLAG_NO_EXP_CONSTTIME = 0x02; /* new with 0.9.7h; the built-in DH
                                       * implementation now uses constant time
                                       * modular exponentiation for secret exponents
                                       * by default. This flag causes the
                                       * faster variable sliding window method to
                                       * be used for all exponents.
                                       */

extern (C):
nothrow:

/* Already defined in ossl_typ.h */
/* typedef dh_st DH; */
/* typedef dh_method DH_METHOD; */

struct dh_method
	{
	const(char)* name;
	/* Methods here */
	ExternC!(int function(DH* dh)) generate_key;
	ExternC!(int function(ubyte* key,const(BIGNUM)* pub_key,DH* dh)) compute_key;
	ExternC!(int function(const(DH)* dh, BIGNUM* r, const(BIGNUM)* a,
				const(BIGNUM)* p, const(BIGNUM)* m, BN_CTX* ctx,
				BN_MONT_CTX* m_ctx)) bn_mod_exp; /* Can be null */

	ExternC!(int function(DH* dh)) init_;
	ExternC!(int function(DH* dh)) finish;
	int flags;
	char* app_data;
	/* If this is non-NULL, it will be used to generate parameters */
	ExternC!(int function(DH* dh, int prime_len, int generator, BN_GENCB* cb)) generate_params;
	};

struct dh_st
	{
	/* This first argument is used to pick up errors when
	 * a DH is passed instead of a EVP_PKEY */
	int pad;
	int version_;
	BIGNUM* p;
	BIGNUM* g;
	c_long length; /* optional */
	BIGNUM* pub_key;	/* g^x */
	BIGNUM* priv_key;	/* x */

	int flags;
	BN_MONT_CTX* method_mont_p;
	/* Place holders if we want to do X9.42 DH */
	BIGNUM* q;
	BIGNUM* j;
	ubyte* seed;
	int seedlen;
	BIGNUM* counter;

	int references;
	CRYPTO_EX_DATA ex_data;
	const(DH_METHOD)* meth;
	ENGINE* engine;
	};

enum DH_GENERATOR_2 = 2;
/* enum DH_GENERATOR_3 = 3; */
enum DH_GENERATOR_5 = 5;

/* DH_check error codes */
enum DH_CHECK_P_NOT_PRIME = 0x01;
enum DH_CHECK_P_NOT_SAFE_PRIME = 0x02;
enum DH_UNABLE_TO_CHECK_GENERATOR = 0x04;
enum DH_NOT_SUITABLE_GENERATOR = 0x08;

/* DH_check_pub_key error codes */
enum DH_CHECK_PUBKEY_TOO_SMALL = 0x01;
enum DH_CHECK_PUBKEY_TOO_LARGE = 0x02;

/* primes p where (p-1)/2 is prime too are called "safe"; we define
   this for backward compatibility: */
alias DH_CHECK_P_NOT_SAFE_PRIME DH_CHECK_P_NOT_STRONG_PRIME;

auto d2i_DHparams_fp()(FILE* fp, void** x) {
	return cast(DH*)ASN1_d2i_fp(cast(ExternC!(void* function()))&DH_new,
		cast(d2i_of_void*)&d2i_DHparams,fp,x);
}
auto i2d_DHparams_fp()(FILE* fp, void* x) { return ASN1_i2d_fp(cast(d2i_of_void*)&i2d_DHparams,fp, x); }
auto d2i_DHparams_bio()(BIO* bp, void** x) { return ASN1_d2i_bio_of!DH(&DH_new,&d2i_DHparams,bp,x); }
auto i2d_DHparams_bio()(BIO* bp, void** x) { return ASN1_i2d_bio_of_const!DH(&i2d_DHparams,bp,x); }

DH* DHparams_dup(DH*);

const(DH_METHOD)* DH_OpenSSL();

void DH_set_default_method(const(DH_METHOD)* meth);
const(DH_METHOD)* DH_get_default_method();
int DH_set_method(DH* dh, const(DH_METHOD)* meth);
DH* DH_new_method(ENGINE* engine);

DH* 	DH_new();
void	DH_free(DH* dh);
int	DH_up_ref(DH* dh);
int	DH_size(const(DH)* dh);
int DH_get_ex_new_index(c_long argl, void* argp, CRYPTO_EX_new* new_func,
	     CRYPTO_EX_dup* dup_func, CRYPTO_EX_free* free_func);
int DH_set_ex_data(DH* d, int idx, void* arg);
void* DH_get_ex_data(DH* d, int idx);

/* Deprecated version */
version(OPENSSL_NO_DEPRECATED) {} else {
DH* 	DH_generate_parameters(int prime_len,int generator,
		ExternC!(void function(int,int,void*)) callback,void* cb_arg);
} /* !defined(OPENSSL_NO_DEPRECATED) */

/* New version */
int	DH_generate_parameters_ex(DH* dh, int prime_len,int generator, BN_GENCB* cb);

int	DH_check(const(DH)* dh,int* codes);
int	DH_check_pub_key(const(DH)* dh,const(BIGNUM)* pub_key, int* codes);
int	DH_generate_key(DH* dh);
int	DH_compute_key(ubyte* key,const(BIGNUM)* pub_key,DH* dh);
DH* 	d2i_DHparams(DH** a,const(ubyte)** pp, c_long length);
int	i2d_DHparams(const(DH)* a,ubyte** pp);
version(OPENSSL_NO_FP_API) {} else {
int	DHparams_print_fp(FILE* fp, const(DH)* x);
}
version(OPENSSL_NO_BIO) {
int	DHparams_print(char* bp, const(DH)* x);
} else {
int	DHparams_print(BIO* bp, const(DH)* x);
}

auto EVP_PKEY_CTX_set_dh_paramgen_prime_len()(EVP_PKEY_CTX* ctx, int len) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_DH, EVP_PKEY_OP_PARAMGEN,
			EVP_PKEY_CTRL_DH_PARAMGEN_PRIME_LEN, len, null);
}

auto EVP_PKEY_CTX_set_dh_paramgen_generator()(EVP_PKEY_CTX* ctx, int gen) {
	return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_DH, EVP_PKEY_OP_PARAMGEN,
			EVP_PKEY_CTRL_DH_PARAMGEN_GENERATOR, gen, null);
}

enum EVP_PKEY_CTRL_DH_PARAMGEN_PRIME_LEN = (EVP_PKEY_ALG_CTRL + 1);
enum EVP_PKEY_CTRL_DH_PARAMGEN_GENERATOR = (EVP_PKEY_ALG_CTRL + 2);


/* BEGIN ERROR CODES */
/* The following lines are auto generated by the script mkerr.pl. Any changes
 * made after this point may be overwritten when the script is next run.
 */
void ERR_load_DH_strings();

/* Error codes for the DH functions. */

/* Function codes. */
enum DH_F_COMPUTE_KEY = 102;
enum DH_F_DHPARAMS_PRINT_FP = 101;
enum DH_F_DH_BUILTIN_GENPARAMS = 106;
enum DH_F_DH_NEW_METHOD = 105;
enum DH_F_DH_PARAM_DECODE = 107;
enum DH_F_DH_PRIV_DECODE = 110;
enum DH_F_DH_PRIV_ENCODE = 111;
enum DH_F_DH_PUB_DECODE = 108;
enum DH_F_DH_PUB_ENCODE = 109;
enum DH_F_DO_DH_PRINT = 100;
enum DH_F_GENERATE_KEY = 103;
enum DH_F_GENERATE_PARAMETERS = 104;
enum DH_F_PKEY_DH_DERIVE = 112;
enum DH_F_PKEY_DH_KEYGEN = 113;

/* Reason codes. */
enum DH_R_BAD_GENERATOR = 101;
enum DH_R_BN_DECODE_ERROR = 109;
enum DH_R_BN_ERROR = 106;
enum DH_R_DECODE_ERROR = 104;
enum DH_R_INVALID_PUBKEY = 102;
enum DH_R_KEYS_NOT_SET = 108;
enum DH_R_MODULUS_TOO_LARGE = 103;
enum DH_R_NO_PARAMETERS_SET = 107;
enum DH_R_NO_PRIVATE_VALUE = 100;
enum DH_R_PARAMETER_ENCODING_ERROR = 105;
