/*
 * 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 the code the Certificate Type TLS extension.
 * This extension is currently gnutls specific.
 */

#include "gnutls_int.h"
#include "gnutls_errors.h"
#include "gnutls_num.h"
#include "ext_cert_type.h"
#include <gnutls_state.h>
#include <gnutls_num.h>

inline static int _gnutls_num2cert_type (int num);
inline static int _gnutls_cert_type2num (int record_size);

/* 
 * In case of a server: if a CERT_TYPE extension type is received then it stores
 * into the session security parameters the new value. The server may use gnutls_session_certificate_type_get(),
 * to access it.
 *
 * In case of a client: If a cert_types have been specified then we send the extension.
 *
 */

int
_gnutls_cert_type_recv_params (gnutls_session_t session,
			       const opaque * data, size_t _data_size)
{
  int new_type = -1, ret, i;
  ssize_t data_size = _data_size;

  if (session->security_parameters.entity == GNUTLS_CLIENT)
    {
      if (data_size > 0)
	{
	  if (data_size != 1)
	    {
	      gnutls_assert ();
	      return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
	    }

	  new_type = _gnutls_num2cert_type (data[0]);

	  if (new_type < 0)
	    {
	      gnutls_assert ();
	      return new_type;
	    }

	  /* Check if we support this cert_type */
	  if ((ret =
	       _gnutls_session_cert_type_supported (session, new_type)) < 0)
	    {
	      gnutls_assert ();
	      return ret;
	    }

	  _gnutls_session_cert_type_set (session, new_type);
	}
    }
  else
    {				/* SERVER SIDE - we must check if the sent cert type is the right one 
				 */
      if (data_size > 1)
	{
	  uint8_t len;

	  len = data[0];
	  DECR_LEN (data_size, len);

	  for (i = 0; i < len; i++)
	    {
	      new_type = _gnutls_num2cert_type (data[i + 1]);

	      if (new_type < 0)
		continue;

	      /* Check if we support this cert_type */
	      if ((ret =
		   _gnutls_session_cert_type_supported (session,
							new_type)) < 0)
		{
		  gnutls_assert ();
		  continue;
		}
	      else
		break;
	      /* new_type is ok */
	    }

	  if (new_type < 0)
	    {
	      gnutls_assert ();
	      return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
	    }

	  if ((ret =
	       _gnutls_session_cert_type_supported (session, new_type)) < 0)
	    {
	      gnutls_assert ();
	      /* The peer has requested unsupported certificate
	       * types. Instead of failing, procceed normally.
	       * (the ciphersuite selection would fail, or a
	       * non certificate ciphersuite will be selected).
	       */
	      return 0;
	    }

	  _gnutls_session_cert_type_set (session, new_type);
	}


    }

  return 0;
}

/* returns data_size or a negative number on failure
 */
int
_gnutls_cert_type_send_params (gnutls_session_t session, opaque * data,
			       size_t data_size)
{
  unsigned len, i;

  /* this function sends the client extension data (dnsname) */
  if (session->security_parameters.entity == GNUTLS_CLIENT)
    {

      if (session->internals.cert_type_priority.algorithms > 0)
	{

	  len = session->internals.cert_type_priority.algorithms;

	  if (len == 1 &&
	      session->internals.cert_type_priority.priority[0] ==
	      GNUTLS_CRT_X509)
	    {
	      /* We don't use this extension if X.509 certificates
	       * are used.
	       */
	      return 0;
	    }

	  if (data_size < len + 1)
	    {
	      gnutls_assert ();
	      return GNUTLS_E_SHORT_MEMORY_BUFFER;
	    }

	  /* this is a vector!
	   */
	  data[0] = (uint8_t) len;

	  for (i = 0; i < len; i++)
	    {
	      data[i + 1] = _gnutls_cert_type2num (session->internals.
						   cert_type_priority.
						   priority[i]);
	    }
	  return len + 1;
	}

    }
  else
    {				/* server side */
      if (session->security_parameters.cert_type != DEFAULT_CERT_TYPE)
	{
	  len = 1;
	  if (data_size < len)
	    {
	      gnutls_assert ();
	      return GNUTLS_E_SHORT_MEMORY_BUFFER;
	    }

	  data[0] =
	    _gnutls_cert_type2num (session->security_parameters.cert_type);
	  return len;
	}


    }

  return 0;
}

/* Maps numbers to record sizes according to the
 * extensions draft.
 */
inline static int
_gnutls_num2cert_type (int num)
{
  switch (num)
    {
    case 0:
      return GNUTLS_CRT_X509;
    case 1:
      return GNUTLS_CRT_OPENPGP;
    default:
      return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
    }
}

/* Maps record size to numbers according to the
 * extensions draft.
 */
inline static int
_gnutls_cert_type2num (int cert_type)
{
  switch (cert_type)
    {
    case GNUTLS_CRT_X509:
      return 0;
    case GNUTLS_CRT_OPENPGP:
      return 1;
    default:
      return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
    }

}