/*
 * Copyright (C) 2011-2017 Intel Corporation. All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * 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.
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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 COPYRIGHT
 * OWNER 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */


#include "sgx_trts.h"
#include "sgx_utils.h"
#include "sgx_eid.h"
#include "error_codes.h"
#include "sgx_ecp_types.h"
#include "sgx_thread.h"
#include <map>
#include "sgx_dh.h"
#include "dh_session_protocol.h"
#include "sgx_tcrypto.h"
#include "datatypes.h"
#include "ProtobufSgxLATransforms_Inititator.h"
#define MAX_SESSION_COUNT  16
#define SGX_CAST(type, item) ((type)(item))
#include <string.h>

// uint32_t session_ids[MAX_SESSION_COUNT] ;

// Our enclave will not be doing LA with more than 1 decryptor enclave at a time.
// We should not need this.
//std::map<int, dh_session_t>g_dest_session_info_map;
dh_session_t global_session_info;
// TODO: May be we need to store all previously assigned session IDs instead of just the counter; to prevent replay attacks -
uint32_t global_session_id=0;

uint32_t verify_peer_enclave_trust(sgx_dh_session_enclave_identity_t* peer_enclave_identity, uint8_t* expected_mr_enclave, uint8_t* expected_mr_signer)
{
  int count=0;
  if(!peer_enclave_identity)
    return INVALID_PARAMETER_ERROR;

  sgx_measurement_t actual_mr_enclave = peer_enclave_identity->mr_enclave;
  sgx_measurement_t actual_mr_signer = peer_enclave_identity->mr_signer;
/*  for(count=0; count<SGX_HASH_SIZE; count++)
  {
    if( actual_mr_enclave.m[count] != expected_mr_enclave[count] )
    {
        return ENCLAVE_TRUST_ERROR;
    }
    if( actual_mr_signer.m[count] != expected_mr_signer[count] )
    {
        return ENCLAVE_TRUST_ERROR; // TODO: Different error here.
    }
  }*/
  return SUCCESS;
}


//Create a session with the destination enclave
int create_session(int fd, uint8_t* expected_mr_enclave, uint8_t* expected_mr_signer, uint8_t* send_mr_signer)
{
  sgx_dh_msg1_t dh_msg1;            //Diffie-Hellman Message 1
  sgx_key_128bit_t dh_aek;        // Session Key
  sgx_dh_msg2_t dh_msg2;            //Diffie-Hellman Message 2
  sgx_dh_msg3_t dh_msg3;            //Diffie-Hellman Message 3

  int retstatus;
  sgx_status_t status = SGX_SUCCESS;
  sgx_dh_session_t sgx_dh_session;
  sgx_dh_session_enclave_identity_t responder_identity;

  memset(&dh_aek,0, sizeof(sgx_key_128bit_t));
  memset(&dh_msg1, 0, sizeof(sgx_dh_msg1_t));
  memset(&dh_msg2, 0, sizeof(sgx_dh_msg2_t));
  memset(&dh_msg3, 0, sizeof(sgx_dh_msg3_t));
  memset(&global_session_info, 0, sizeof(dh_session_t));

  //Intialize the session as a session initiator
  status = sgx_dh_init_session(SGX_DH_SESSION_INITIATOR, &sgx_dh_session);
  if(status != SGX_SUCCESS)
    return status;

  retstatus = session_request_call(fd, &dh_msg1);//, &session_id);
  if(retstatus!=0)
    return retstatus;

  //Process the message 1 obtained from desination enclave and generate message 2
  status = sgx_dh_initiator_proc_msg1(&dh_msg1, &dh_msg2, &sgx_dh_session);
  if(SGX_SUCCESS != status)
    return status;

  //Send Message 2 to Destination Enclave and get Message 3 in return
  retstatus = exchange_report_call( fd, &dh_msg2, &dh_msg3); //, &session_id);
  if(retstatus!=0)
	 return retstatus;

  //Process Message 3 obtained from the destination enclave
  status = sgx_dh_initiator_proc_msg3(&dh_msg3, &sgx_dh_session, &dh_aek, &responder_identity);
  if(SGX_SUCCESS != status)
    return status;

  // Verify the identity of the destination enclave
  retstatus = verify_peer_enclave_trust(&responder_identity, expected_mr_enclave, expected_mr_signer);
  if(retstatus != 0)
    return retstatus;

  memcpy(global_session_info.active.AEK, &dh_aek, sizeof(sgx_key_128bit_t));
  global_session_info.session_id = 1; // TODO: session_id;
  global_session_info.active.counter = 0;
  global_session_info.status = ACTIVE;
  memset(&dh_aek,0, sizeof(sgx_key_128bit_t));

  return 0;
}