/*
 * Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation
 *
 * Author: Nikos Mavroyanopoulos
 *
 * This file is part of GNUTLS.
 *
 * The GNUTLS library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 * USA
 *
 */

/* This file contains code for RSA temporary keys. These keys are
 * only used in export cipher suites.
 */

#include <gnutls_int.h>
#include <gnutls_errors.h>
#include <gnutls_datum.h>
#include <gnutls_rsa_export.h>
#include "x509/x509.h"
#include "x509/privkey.h"
#include "debug.h"

/* This function takes a number of bits and returns a supported
 * number of bits. Ie a number of bits that we have a prime in the
 * dh_primes structure.
 */

#define MAX_SUPPORTED_BITS 512

/* returns e and m, depends on the requested bits.
 * We only support limited key sizes.
 */
const mpi_t *
_gnutls_rsa_params_to_mpi (gnutls_rsa_params_t rsa_params)
{
  if (rsa_params == NULL)
    {
      return NULL;
    }

  return rsa_params->params;

}

/* resarr will contain: modulus(0), public exponent(1), private exponent(2),
 * prime1 - p (3), prime2 - q(4), u (5).
 */
int
_gnutls_rsa_generate_params (mpi_t * resarr, int *resarr_len, int bits)
{

  int ret;
  gcry_sexp_t parms, key, list;

  ret = gcry_sexp_build (&parms, NULL, "(genkey(rsa(nbits %d)))", bits);
  if (ret != 0)
    {
      gnutls_assert ();
      return GNUTLS_E_INTERNAL_ERROR;
    }

  /* generate the RSA key */
  ret = gcry_pk_genkey (&key, parms);
  gcry_sexp_release (parms);

  if (ret != 0)
    {
      gnutls_assert ();
      return GNUTLS_E_INTERNAL_ERROR;
    }

  list = gcry_sexp_find_token (key, "n", 0);
  if (list == NULL)
    {
      gnutls_assert ();
      gcry_sexp_release (key);
      return GNUTLS_E_INTERNAL_ERROR;
    }

  resarr[0] = gcry_sexp_nth_mpi (list, 1, 0);
  gcry_sexp_release (list);

  list = gcry_sexp_find_token (key, "e", 0);
  if (list == NULL)
    {
      gnutls_assert ();
      gcry_sexp_release (key);
      return GNUTLS_E_INTERNAL_ERROR;
    }

  resarr[1] = gcry_sexp_nth_mpi (list, 1, 0);
  gcry_sexp_release (list);

  list = gcry_sexp_find_token (key, "d", 0);
  if (list == NULL)
    {
      gnutls_assert ();
      gcry_sexp_release (key);
      return GNUTLS_E_INTERNAL_ERROR;
    }

  resarr[2] = gcry_sexp_nth_mpi (list, 1, 0);
  gcry_sexp_release (list);

  list = gcry_sexp_find_token (key, "p", 0);
  if (list == NULL)
    {
      gnutls_assert ();
      gcry_sexp_release (key);
      return GNUTLS_E_INTERNAL_ERROR;
    }

  resarr[3] = gcry_sexp_nth_mpi (list, 1, 0);
  gcry_sexp_release (list);


  list = gcry_sexp_find_token (key, "q", 0);
  if (list == NULL)
    {
      gnutls_assert ();
      gcry_sexp_release (key);
      return GNUTLS_E_INTERNAL_ERROR;
    }

  resarr[4] = gcry_sexp_nth_mpi (list, 1, 0);
  gcry_sexp_release (list);


  list = gcry_sexp_find_token (key, "u", 0);
  if (list == NULL)
    {
      gnutls_assert ();
      gcry_sexp_release (key);
      return GNUTLS_E_INTERNAL_ERROR;
    }

  resarr[5] = gcry_sexp_nth_mpi (list, 1, 0);
  gcry_sexp_release (list);

  gcry_sexp_release (key);

  _gnutls_dump_mpi ("n: ", resarr[0]);
  _gnutls_dump_mpi ("e: ", resarr[1]);
  _gnutls_dump_mpi ("d: ", resarr[2]);
  _gnutls_dump_mpi ("p: ", resarr[3]);
  _gnutls_dump_mpi ("q: ", resarr[4]);
  _gnutls_dump_mpi ("u: ", resarr[5]);

  *resarr_len = 6;

  return 0;

}


/**
  * gnutls_rsa_params_import_raw - This function will replace the old RSA parameters
  * @rsa_params: Is a structure will hold the parameters
  * @m: holds the modulus
  * @e: holds the public exponent
  * @d: holds the private exponent
  * @p: holds the first prime (p)
  * @q: holds the second prime (q)
  * @u: holds the coefficient
  *
  * This function will replace the parameters in the given structure.
  * The new parameters should be stored in the appropriate gnutls_datum. 
  * 
  **/
int
gnutls_rsa_params_import_raw (gnutls_rsa_params_t rsa_params,
			      const gnutls_datum_t * m,
			      const gnutls_datum_t * e,
			      const gnutls_datum_t * d,
			      const gnutls_datum_t * p,
			      const gnutls_datum_t * q,
			      const gnutls_datum_t * u)
{
  return gnutls_x509_privkey_import_rsa_raw (rsa_params, m, e, d, p, q, u);
}

/**
  * gnutls_rsa_params_init - This function will initialize the temporary RSA parameters
  * @rsa_params: Is a structure that will hold the parameters
  *
  * This function will initialize the temporary RSA parameters structure.
  *
  **/
int
gnutls_rsa_params_init (gnutls_rsa_params_t * rsa_params)
{
  int ret;

  ret = gnutls_x509_privkey_init (rsa_params);
  if (ret < 0)
    {
      gnutls_assert ();
      return ret;
    }

  (*rsa_params)->crippled = 1;

  return 0;
}

/**
  * gnutls_rsa_params_deinit - This function will deinitialize the RSA parameters
  * @rsa_params: Is a structure that holds the parameters
  *
  * This function will deinitialize the RSA parameters structure.
  *
  **/
void
gnutls_rsa_params_deinit (gnutls_rsa_params_t rsa_params)
{
  gnutls_x509_privkey_deinit (rsa_params);
}

/**
  * gnutls_rsa_params_cpy - This function will copy an RSA parameters structure
  * @dst: Is the destination structure, which should be initialized.
  * @src: Is the source structure
  *
  * This function will copy the RSA parameters structure from source
  * to destination.
  *
  **/
int
gnutls_rsa_params_cpy (gnutls_rsa_params_t dst, gnutls_rsa_params_t src)
{
  return gnutls_x509_privkey_cpy (dst, src);
}

/**
  * gnutls_rsa_params_generate2 - This function will generate temporary RSA parameters
  * @params: The structure where the parameters will be stored
  * @bits: is the prime's number of bits
  *
  * This function will generate new temporary RSA parameters for use in 
  * RSA-EXPORT ciphersuites.  This function is normally slow. 
  * 
  * Note that if the parameters are to be used in export cipher suites the 
  * bits value should be 512 or less.
  * Also note that the generation of new RSA parameters is only useful
  * to servers. Clients use the parameters sent by the server, thus it's
  * no use calling this in client side.
  *
  **/
int
gnutls_rsa_params_generate2 (gnutls_rsa_params_t params, unsigned int bits)
{
  return gnutls_x509_privkey_generate (params, GNUTLS_PK_RSA, bits, 0);
}

/**
  * gnutls_rsa_params_import_pkcs1 - This function will import RSA params from a pkcs1 structure
  * @params: A structure where the parameters will be copied to
  * @pkcs1_params: should contain a PKCS1 RSAPublicKey structure PEM or DER encoded
  * @format: the format of params. PEM or DER.
  *
  * This function will extract the RSAPublicKey found in a PKCS1 formatted
  * structure. 
  *
  * If the structure is PEM encoded, it should have a header
  * of "BEGIN RSA PRIVATE KEY".
  *
  * In case of failure a negative value will be returned, and
  * 0 on success.
  *
  **/
int
gnutls_rsa_params_import_pkcs1 (gnutls_rsa_params_t params,
				const gnutls_datum_t * pkcs1_params,
				gnutls_x509_crt_fmt_t format)
{
  return gnutls_x509_privkey_import (params, pkcs1_params, format);
}


/**
  * gnutls_rsa_params_export_pkcs1 - This function will export RSA params to a pkcs1 structure
  * @params: Holds the RSA parameters
  * @format: the format of output params. One of PEM or DER.
  * @params_data: will contain a PKCS1 RSAPublicKey structure PEM or DER encoded
  * @params_data_size: holds the size of params_data (and will be replaced by the actual size of parameters)
  *
  * This function will export the given RSA parameters to a PKCS1
  * RSAPublicKey structure. If the buffer provided is not long enough to 
  * hold the output, then GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
  *
  * If the structure is PEM encoded, it will have a header
  * of "BEGIN RSA PRIVATE KEY".
  *
  * In case of failure a negative value will be returned, and
  * 0 on success.
  *
  **/
int
gnutls_rsa_params_export_pkcs1 (gnutls_rsa_params_t params,
				gnutls_x509_crt_fmt_t format,
				unsigned char *params_data,
				size_t * params_data_size)
{
  return gnutls_x509_privkey_export (params, format,
				     params_data, params_data_size);
}


/**
  * gnutls_rsa_params_export_raw - This function will export the RSA parameters
  * @params: a structure that holds the rsa parameters
  * @m: will hold the modulus
  * @e: will hold the public exponent
  * @d: will hold the private exponent
  * @p: will hold the first prime (p)
  * @q: will hold the second prime (q)
  * @u: will hold the coefficient
  * @bits: if non null will hold the prime's number of bits
  *
  * This function will export the RSA parameters found in the given
  * structure. The new parameters will be allocated using
  * gnutls_malloc() and will be stored in the appropriate datum.
  * 
  **/
int
gnutls_rsa_params_export_raw (gnutls_rsa_params_t params,
			      gnutls_datum_t * m, gnutls_datum_t * e,
			      gnutls_datum_t * d, gnutls_datum_t * p,
			      gnutls_datum_t * q, gnutls_datum_t * u,
			      unsigned int *bits)
{
  int ret;

  ret = gnutls_x509_privkey_export_rsa_raw (params, m, e, d, p, q, u);
  if (ret < 0)
    {
      gnutls_assert ();
      return ret;
    }

  if (bits)
    *bits = _gnutls_mpi_get_nbits (params->params[3]);

  return 0;

}