/*

 * Copyright (C) 2005-2010 Martin Willi

 * Copyright (C) 2005 Jan Hutter

 *

 * Copyright (C) secunet Security Networks AG

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the

 * Free Software Foundation; either version 2 of the License, or (at your

 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.

 *

 * This program 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 General Public License

 * for more details.

 */

#include <stddef.h>

#include "ke_payload.h"

#include <encoding/payloads/encodings.h>

typedef struct private_ke_payload_t private_ke_payload_t;

/**

 * Private data of an ke_payload_t object.

 */

struct private_ke_payload_t {

  /**

   * Public ke_payload_t interface.

   */

  ke_payload_t public;

  /**

   * Next payload type.

   */

  uint8_t  next_payload;

  /**

   * Critical flag.

   */

  bool critical;

  /**

   * Reserved bits

   */

  bool reserved_bit[7];

  /**

   * Reserved bytes

   */

  uint8_t reserved_byte[2];

  /**

   * Length of this payload.

   */

  uint16_t payload_length;

  /**

   * Key exchange method number.

   */

  uint16_t ke_method;

  /**

   * Key Exchange Data of this KE payload.

   */

  chunk_t key_exchange_data;

  /**

   * Payload type, PLV2_KEY_EXCHANGE or PLV1_KEY_EXCHANGE

   */

  payload_type_t type;

};

/**

 * Encoding rules for IKEv2 key exchange payload.

 */

static encoding_rule_t encodings_v2[] = {

  /* 1 Byte next payload type, stored in the field next_payload */

  { U_INT_8,        offsetof(private_ke_payload_t, next_payload)  },

  /* the critical bit */

  { FLAG,         offsetof(private_ke_payload_t, critical)    },

  /* 7 Bit reserved bits */

  { RESERVED_BIT,     offsetof(private_ke_payload_t, reserved_bit[0]) },

  { RESERVED_BIT,     offsetof(private_ke_payload_t, reserved_bit[1]) },

  { RESERVED_BIT,     offsetof(private_ke_payload_t, reserved_bit[2]) },

  { RESERVED_BIT,     offsetof(private_ke_payload_t, reserved_bit[3]) },

  { RESERVED_BIT,     offsetof(private_ke_payload_t, reserved_bit[4]) },

  { RESERVED_BIT,     offsetof(private_ke_payload_t, reserved_bit[5]) },

  { RESERVED_BIT,     offsetof(private_ke_payload_t, reserved_bit[6]) },

  /* Length of the whole payload*/

  { PAYLOAD_LENGTH,   offsetof(private_ke_payload_t, payload_length)  },

  /* Key exchange method number as 16 bit field*/

  { U_INT_16,       offsetof(private_ke_payload_t, ke_method)   },

  /* 2 reserved bytes */

  { RESERVED_BYTE,    offsetof(private_ke_payload_t, reserved_byte[0])},

  { RESERVED_BYTE,    offsetof(private_ke_payload_t, reserved_byte[1])},

  /* Key Exchange Data is from variable size */

  { CHUNK_DATA,     offsetof(private_ke_payload_t, key_exchange_data)},

};

/*

                           1                   2                   3

       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      ! Next Payload  !C!  RESERVED   !         Payload Length        !

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      !          KE method #          !           RESERVED            !

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      !                                                               !

      ~                       Key Exchange Data                       ~

      !                                                               !

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

*/

static encoding_rule_t encodings_v1[] = {

  /* 1 Byte next payload type, stored in the field next_payload */

  { U_INT_8,        offsetof(private_ke_payload_t, next_payload)  },

  /* Reserved Byte */

  { RESERVED_BYTE,    offsetof(private_ke_payload_t, reserved_byte[0])},

  /* Length of the whole payload*/

  { PAYLOAD_LENGTH,   offsetof(private_ke_payload_t, payload_length)  },

  /* Key Exchange Data is from variable size */

  { CHUNK_DATA,     offsetof(private_ke_payload_t, key_exchange_data)},

};

/*

                           1                   2                   3

       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      ! Next Payload  !    RESERVED   !         Payload Length        !

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      !                                                               !

      ~                       Key Exchange Data                       ~

      !                                                               !

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

*/

METHOD(payload_t, verify, status_t,

  private_ke_payload_t *this)

{

  return SUCCESS;

}

METHOD(payload_t, get_encoding_rules, int,

  private_ke_payload_t *this, encoding_rule_t **rules)

{

  if (this->type == PLV2_KEY_EXCHANGE)

  {

    *rules = encodings_v2;

    return countof(encodings_v2);

  }

  *rules = encodings_v1;

  return countof(encodings_v1);

}

METHOD(payload_t, get_header_length, int,

  private_ke_payload_t *this)

{

  if (this->type == PLV2_KEY_EXCHANGE)

  {

    return 8;

  }

  return 4;

}

METHOD(payload_t, get_type, payload_type_t,

  private_ke_payload_t *this)

{

  return this->type;

}

METHOD(payload_t, get_next_type, payload_type_t,

  private_ke_payload_t *this)

{

  return this->next_payload;

}

METHOD(payload_t, set_next_type, void,

  private_ke_payload_t *this,payload_type_t type)

{

  this->next_payload = type;

}

METHOD(payload_t, get_length, size_t,

  private_ke_payload_t *this)

{

  return this->payload_length;

}

METHOD(ke_payload_t, get_key_exchange_data, chunk_t,

  private_ke_payload_t *this)

{

  return this->key_exchange_data;

}

METHOD(ke_payload_t, get_key_exchange_method, key_exchange_method_t,

  private_ke_payload_t *this)

{

  return this->ke_method;

}

METHOD2(payload_t, ke_payload_t, destroy, void,

  private_ke_payload_t *this)

{

  free(this->key_exchange_data.ptr);

  free(this);

}

/*

 * Described in header

 */

ke_payload_t *ke_payload_create(payload_type_t type)

{

  private_ke_payload_t *this;

  INIT(this,

    .public = {

      .payload_interface = {

        .verify = _verify,

        .get_encoding_rules = _get_encoding_rules,

        .get_header_length = _get_header_length,

        .get_length = _get_length,

        .get_next_type = _get_next_type,

        .set_next_type = _set_next_type,

        .get_type = _get_type,

        .destroy = _destroy,

      },

      .get_key_exchange_data = _get_key_exchange_data,

      .get_key_exchange_method = _get_key_exchange_method,

      .destroy = _destroy,

    },

    .next_payload = PL_NONE,

    .ke_method = KE_NONE,

    .type = type,

  );

  this->payload_length = get_header_length(this);

  return &this->public;

}

/*

 * Described in header

 */

ke_payload_t *ke_payload_create_from_key_exchange(payload_type_t type,

                          key_exchange_t *ke)

{

  private_ke_payload_t *this;

  chunk_t value;

  if (!ke->get_public_key(ke, &value))

  {

    return NULL;

  }

  this = (private_ke_payload_t*)ke_payload_create(type);

  this->key_exchange_data = value;

  this->ke_method = ke->get_method(ke);

  this->payload_length += this->key_exchange_data.len;

  return &this->public;

}