/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */

/*! \file nr_nas_msg_sim.c
 * \brief simulator for nr nas message
 * \author Yoshio INOUE, Masayuki HARADA
 * \email yoshio.inoue@fujitsu.com,masayuki.harada@fujitsu.com
 * \date 2020
 * \version 0.1
 */


#include <string.h> // memset
#include <stdlib.h> // malloc, free

#include "nas_log.h"
#include "TLVDecoder.h"
#include "TLVEncoder.h"
#include "nr_nas_msg_sim.h"
#include "aka_functions.h"
#include "secu_defs.h"
#include "PduSessionEstablishRequest.h"
#include "PduSessionEstablishmentAccept.h"
#include "intertask_interface.h"
#include "openair2/RRC/NAS/nas_config.h"
#include <openair3/UICC/usim_interface.h>
#include <openair3/NAS/COMMON/NR_NAS_defs.h>
#include <openair1/PHY/phy_extern_nr_ue.h>
#include <openair1/SIMULATION/ETH_TRANSPORT/proto.h>
#include "openair2/SDAP/nr_sdap/nr_sdap.h"

uint8_t  *registration_request_buf;
uint32_t  registration_request_len;
extern char *baseNetAddress;
extern uint16_t NB_UE_INST;
static ue_sa_security_key_t ** ue_security_key;

static int nas_protected_security_header_encode(
  char                                       *buffer,
  const fgs_nas_message_security_header_t    *header,
  int                                         length)
{
  LOG_FUNC_IN;

  int size = 0;

  /* Encode the protocol discriminator) */
  ENCODE_U8(buffer, header->protocol_discriminator, size);

  /* Encode the security header type */
  ENCODE_U8(buffer+size, (header->security_header_type & 0xf), size);

  /* Encode the message authentication code */
  ENCODE_U32(buffer+size, header->message_authentication_code, size);
  /* Encode the sequence number */
  ENCODE_U8(buffer+size, header->sequence_number, size);

  LOG_FUNC_RETURN (size);
}

static int _nas_mm_msg_encode_header(const mm_msg_header_t *header,
                                  uint8_t *buffer, uint32_t len) {
  int size = 0;

  /* Check the buffer length */
  if (len < sizeof(mm_msg_header_t)) {
    return (TLV_ENCODE_BUFFER_TOO_SHORT);
  }

  /* Check the protocol discriminator */
  if (header->ex_protocol_discriminator != FGS_MOBILITY_MANAGEMENT_MESSAGE) {
    LOG_TRACE(ERROR, "ESM-MSG   - Unexpected extened protocol discriminator: 0x%x",
              header->ex_protocol_discriminator);
    return (TLV_ENCODE_PROTOCOL_NOT_SUPPORTED);
  }

  /* Encode the extendedprotocol discriminator */
  ENCODE_U8(buffer + size, header->ex_protocol_discriminator, size);
  /* Encode the security header type */
  ENCODE_U8(buffer + size, (header->security_header_type & 0xf), size);
  /* Encode the message type */
  ENCODE_U8(buffer + size, header->message_type, size);
  return (size);
}


int mm_msg_encode(MM_msg *mm_msg, uint8_t *buffer, uint32_t len) {
  LOG_FUNC_IN;
  int header_result;
  int encode_result;
  uint8_t msg_type = mm_msg->header.message_type;


  /* First encode the EMM message header */
  header_result = _nas_mm_msg_encode_header(&mm_msg->header, buffer, len);

  if (header_result < 0) {
    LOG_TRACE(ERROR, "EMM-MSG   - Failed to encode EMM message header "
              "(%d)", header_result);
    LOG_FUNC_RETURN(header_result);
  }

  buffer += header_result;
  len -= header_result;

  switch(msg_type) {
    case REGISTRATION_REQUEST:
      encode_result = encode_registration_request(&mm_msg->registration_request, buffer, len);
      break;
    case FGS_IDENTITY_RESPONSE:
      encode_result = encode_identiy_response(&mm_msg->fgs_identity_response, buffer, len);
      break;
    case FGS_AUTHENTICATION_RESPONSE:
      encode_result = encode_fgs_authentication_response(&mm_msg->fgs_auth_response, buffer, len);
      break;
    case FGS_SECURITY_MODE_COMPLETE:
      encode_result = encode_fgs_security_mode_complete(&mm_msg->fgs_security_mode_complete, buffer, len);
      break;
    case FGS_UPLINK_NAS_TRANSPORT:
      encode_result = encode_fgs_uplink_nas_transport(&mm_msg->uplink_nas_transport, buffer, len);
      break;
    default:
      LOG_TRACE(ERROR, "EMM-MSG   - Unexpected message type: 0x%x",
    		  mm_msg->header.message_type);
      encode_result = TLV_ENCODE_WRONG_MESSAGE_TYPE;
      break;
      /* TODO: Handle not standard layer 3 messages: SERVICE_REQUEST */
  }

  if (encode_result < 0) {
    LOG_TRACE(ERROR, "EMM-MSG   - Failed to encode L3 EMM message 0x%x "
              "(%d)", mm_msg->header.message_type, encode_result);
  }

  if (encode_result < 0)
    LOG_FUNC_RETURN (encode_result);

  LOG_FUNC_RETURN (header_result + encode_result);
}

void transferRES(uint8_t ck[16], uint8_t ik[16], uint8_t *input, uint8_t rand[16], uint8_t *output, uicc_t* uicc) {
  uint8_t S[100]={0};
  S[0] = 0x6B;
  servingNetworkName (S+1, uicc->imsiStr, uicc->nmc_size);
  int netNamesize = strlen((char*)S+1);
  S[1 + netNamesize] = (netNamesize & 0xff00) >> 8;
  S[2 + netNamesize] = (netNamesize & 0x00ff);
  for (int i = 0; i < 16; i++)
    S[3 + netNamesize + i] = rand[i];
  S[19 + netNamesize] = 0x00;
  S[20 + netNamesize] = 0x10;
  for (int i = 0; i < 8; i++)
    S[21 + netNamesize + i] = input[i];
  S[29 + netNamesize] = 0x00;
  S[30 + netNamesize] = 0x08;

  uint8_t plmn[3] = { 0x02, 0xf8, 0x39 };
  uint8_t oldS[100];
  oldS[0] = 0x6B;
  memcpy(&oldS[1], plmn, 3);
  oldS[4] = 0x00;
  oldS[5] = 0x03;
  for (int i = 0; i < 16; i++)
    oldS[6 + i] = rand[i];
  oldS[22] = 0x00;
  oldS[23] = 0x10;
  for (int i = 0; i < 8; i++)
    oldS[24 + i] = input[i];
  oldS[32] = 0x00;
  oldS[33] = 0x08;


  uint8_t key[32];
  memcpy(&key[0], ck, 16);
  memcpy(&key[16], ik, 16);  //KEY
  uint8_t out[32];
  kdf(key, 32, S, 31 + netNamesize, out, 32);
  for (int i = 0; i < 16; i++)
    output[i] = out[16 + i];
}

void derive_kausf(uint8_t ck[16], uint8_t ik[16], uint8_t sqn[6], uint8_t kausf[32], uicc_t *uicc) {
  uint8_t S[100]={0};
  uint8_t key[32];

  memcpy(&key[0], ck, 16);
  memcpy(&key[16], ik, 16);  //KEY
  S[0] = 0x6A;
  servingNetworkName (S+1, uicc->imsiStr, uicc->nmc_size);
  int netNamesize = strlen((char*)S+1);
  S[1 + netNamesize] = (uint8_t)((netNamesize & 0xff00) >> 8);
  S[2 + netNamesize] = (uint8_t)(netNamesize & 0x00ff);
  for (int i = 0; i < 6; i++) {
   S[3 + netNamesize + i] = sqn[i];
  }
  S[9 + netNamesize] = 0x00;
  S[10 + netNamesize] = 0x06;
  kdf(key, 32, S, 11 + netNamesize, kausf, 32);
}

void derive_kseaf(uint8_t kausf[32], uint8_t kseaf[32], uicc_t *uicc) {
  uint8_t S[100]={0};
  S[0] = 0x6C;  //FC
  servingNetworkName (S+1, uicc->imsiStr, uicc->nmc_size);
  int netNamesize = strlen((char*)S+1);
  S[1 + netNamesize] = (uint8_t)((netNamesize & 0xff00) >> 8);
  S[2 + netNamesize] = (uint8_t)(netNamesize & 0x00ff);
  kdf(kausf, 32, S, 3 + netNamesize, kseaf, 32);
}

void derive_kamf(uint8_t *kseaf, uint8_t *kamf, uint16_t abba, uicc_t* uicc) {
  int imsiLen = strlen(uicc->imsiStr);
  uint8_t S[100];
  S[0] = 0x6D;  //FC = 0x6D
  memcpy(&S[1], uicc->imsiStr, imsiLen );
  S[1 + imsiLen] = (uint8_t)((imsiLen & 0xff00) >> 8);
  S[2 + imsiLen] = (uint8_t)(imsiLen & 0x00ff);
  S[3 + imsiLen] = abba & 0x00ff;
  S[4 + imsiLen] = (abba & 0xff00) >> 8;
  S[5 + imsiLen] = 0x00;
  S[6 + imsiLen] = 0x02;
  kdf(kseaf, 32, S, 7 + imsiLen, kamf, 32);
}

//------------------------------------------------------------------------------
void derive_knas(algorithm_type_dist_t nas_alg_type, uint8_t nas_alg_id, uint8_t kamf[32], uint8_t *knas_int) {
  uint8_t S[20];
  uint8_t out[32] = { 0 };
  S[0] = 0x69;  //FC
  S[1] = (uint8_t)(nas_alg_type & 0xFF);
  S[2] = 0x00;
  S[3] = 0x01;
  S[4] = nas_alg_id;
  S[5] = 0x00;
  S[6] = 0x01;
  kdf(kamf, 32, S, 7, out, 32);
  for (int i = 0; i < 16; i++)
    knas_int[i] = out[16 + i];
}

void derive_kgnb(uint8_t kamf[32], uint32_t count, uint8_t *kgnb){
  /* Compute the KDF input parameter
   * S = FC(0x6E) || UL NAS Count || 0x00 0x04 || 0x01 || 0x00 0x01
   */
  uint8_t  input[32];
  //    uint16_t length    = 4;
  //    int      offset    = 0;
  uint8_t out[32] = { 0 };

  LOG_TRACE(INFO, "%s  with count= %d", __FUNCTION__, count);
  memset(input, 0, 32);
  input[0] = 0x6E;
  // P0
  input[1] = count >> 24;
  input[2] = (uint8_t)(count >> 16);
  input[3] = (uint8_t)(count >> 8);
  input[4] = (uint8_t)count;
  // L0
  input[5] = 0;
  input[6] = 4;
  // P1
  input[7] = 0x01;
  // L1
  input[8] = 0;
  input[9] = 1;

  kdf(kamf, 32, input, 10, out, 32);
  for (int i = 0; i < 32; i++)
    kgnb[i] = out[i];
  printf("kgnb : ");
  for(int pp=0;pp<32;pp++)
   printf("%02x ",kgnb[pp]);
  printf("\n");
}

void derive_ue_keys(int Mod_id, uint8_t *buf, uicc_t *uicc) {
  uint8_t ak[6];
  uint8_t sqn[6];

  AssertFatal (Mod_id < NB_UE_INST, "Failed, Mod_id %d is over NB_UE_INST!\n", Mod_id);
  if(ue_security_key[Mod_id]){
    // clear old key
    memset(ue_security_key[Mod_id],0,sizeof(ue_sa_security_key_t));
  }else{
    // Allocate new memory
    ue_security_key[Mod_id]=(ue_sa_security_key_t *)calloc(1,sizeof(ue_sa_security_key_t));
  }
  uint8_t *kausf = ue_security_key[Mod_id]->kausf;
  uint8_t *kseaf = ue_security_key[Mod_id]->kseaf;
  uint8_t *kamf = ue_security_key[Mod_id]->kamf;
  uint8_t *knas_int = ue_security_key[Mod_id]->knas_int;
  uint8_t *output = ue_security_key[Mod_id]->res;
  uint8_t *rand = ue_security_key[Mod_id]->rand;
  uint8_t *kgnb = ue_security_key[Mod_id]->kgnb;

  // get RAND for authentication request
  for(int index = 0; index < 16;index++){
    rand[index] = buf[8+index];
  }

  uint8_t resTemp[16];
  uint8_t ck[16], ik[16];
  f2345(uicc->key, rand, resTemp, ck, ik, ak, uicc->opc);

  transferRES(ck, ik, resTemp, rand, output, uicc);

  for(int index = 0; index < 6; index++){
    sqn[index] = buf[26+index];
  }

  derive_kausf(ck, ik, sqn, kausf, uicc);
  derive_kseaf(kausf, kseaf, uicc);
  derive_kamf(kseaf, kamf, 0x0000, uicc);
  derive_knas(0x02, 2, kamf, knas_int);
  derive_kgnb(kamf,0,kgnb);

  printf("kausf:");
  for(int i = 0; i < 32; i++){
    printf("%x ", kausf[i]);
  }
  printf("\n");

  printf("kseaf:");
  for(int i = 0; i < 32; i++){
    printf("%x ", kseaf[i]);
  }

  printf("\n");

  printf("kamf:");
  for(int i = 0; i < 32; i++){
    printf("%x ", kamf[i]);
  }
  printf("\n");

  printf("knas_int:\n");
  for(int i = 0; i < 16; i++){
    printf("%x ", knas_int[i]);
  }
  printf("\n");
}

void generateRegistrationRequest(as_nas_info_t *initialNasMsg, int Mod_id) {
  int size = sizeof(mm_msg_header_t);
  fgs_nas_message_t nas_msg={0};
  MM_msg *mm_msg;
  uicc_t * uicc=checkUicc(Mod_id);

  mm_msg = &nas_msg.plain.mm_msg;
  // set header
  mm_msg->header.ex_protocol_discriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  mm_msg->header.security_header_type = PLAIN_5GS_MSG;
  mm_msg->header.message_type = REGISTRATION_REQUEST;


  // set registration request
  mm_msg->registration_request.protocoldiscriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  size += 1;
  mm_msg->registration_request.securityheadertype = PLAIN_5GS_MSG;
  size += 1;
  mm_msg->registration_request.messagetype = REGISTRATION_REQUEST;
  size += 1;
  mm_msg->registration_request.fgsregistrationtype = INITIAL_REGISTRATION;
  mm_msg->registration_request.naskeysetidentifier.naskeysetidentifier = 1;
  size += 1;
  if(0){
    mm_msg->registration_request.fgsmobileidentity.guti.typeofidentity = FGS_MOBILE_IDENTITY_5G_GUTI;
    mm_msg->registration_request.fgsmobileidentity.guti.amfregionid = 0xca;
    mm_msg->registration_request.fgsmobileidentity.guti.amfpointer = 0;
    mm_msg->registration_request.fgsmobileidentity.guti.amfsetid = 1016;
    mm_msg->registration_request.fgsmobileidentity.guti.tmsi = 10;
    mm_msg->registration_request.fgsmobileidentity.guti.mncdigit1 =
      uicc->nmc_size==2 ? uicc->imsiStr[3]-'0' :  uicc->imsiStr[4]-'0';
    mm_msg->registration_request.fgsmobileidentity.guti.mncdigit2 =
      uicc->nmc_size==2 ? uicc->imsiStr[4]-'0' :  uicc->imsiStr[5]-'0';
    mm_msg->registration_request.fgsmobileidentity.guti.mncdigit3 =
      uicc->nmc_size==2 ? 0xf : uicc->imsiStr[3]-'0';
    mm_msg->registration_request.fgsmobileidentity.guti.mccdigit1 = uicc->imsiStr[0]-'0';
    mm_msg->registration_request.fgsmobileidentity.guti.mccdigit2 = uicc->imsiStr[1]-'0';
    mm_msg->registration_request.fgsmobileidentity.guti.mccdigit3 = uicc->imsiStr[2]-'0';

    size += 13;

  } else {
    mm_msg->registration_request.fgsmobileidentity.suci.typeofidentity = FGS_MOBILE_IDENTITY_SUCI;
    mm_msg->registration_request.fgsmobileidentity.suci.mncdigit1 =
     uicc->nmc_size==2 ? uicc->imsiStr[3]-'0' :  uicc->imsiStr[4]-'0';
    mm_msg->registration_request.fgsmobileidentity.suci.mncdigit2 =
      uicc->nmc_size==2 ? uicc->imsiStr[4]-'0' :  uicc->imsiStr[5]-'0';
    mm_msg->registration_request.fgsmobileidentity.suci.mncdigit3 =
      uicc->nmc_size==2 ? 0xf : uicc->imsiStr[3]-'0';
    mm_msg->registration_request.fgsmobileidentity.suci.mccdigit1 = uicc->imsiStr[0]-'0';
    mm_msg->registration_request.fgsmobileidentity.suci.mccdigit2 = uicc->imsiStr[1]-'0';
    mm_msg->registration_request.fgsmobileidentity.suci.mccdigit3 = uicc->imsiStr[2]-'0';
    memcpy(mm_msg->registration_request.fgsmobileidentity.suci.schemeoutput, uicc->imsiStr+3+uicc->nmc_size, strlen(uicc->imsiStr) - (3+uicc->nmc_size));
    size += sizeof(Suci5GSMobileIdentity_t);
  }

  mm_msg->registration_request.presencemask |= REGISTRATION_REQUEST_5GMM_CAPABILITY_PRESENT;
  mm_msg->registration_request.fgmmcapability.iei = REGISTRATION_REQUEST_5GMM_CAPABILITY_IEI;
  mm_msg->registration_request.fgmmcapability.length = 1;
  mm_msg->registration_request.fgmmcapability.value = 0x7;
  size += 3;

  mm_msg->registration_request.presencemask |= REGISTRATION_REQUEST_UE_SECURITY_CAPABILITY_PRESENT;
  mm_msg->registration_request.nruesecuritycapability.iei = REGISTRATION_REQUEST_UE_SECURITY_CAPABILITY_IEI;
  mm_msg->registration_request.nruesecuritycapability.length = 8;
  mm_msg->registration_request.nruesecuritycapability.fg_EA = 0x80;
  mm_msg->registration_request.nruesecuritycapability.fg_IA = 0x20;
  mm_msg->registration_request.nruesecuritycapability.EEA = 0;
  mm_msg->registration_request.nruesecuritycapability.EIA = 0;
  size += 10;

  // encode the message
  initialNasMsg->data = malloc16_clear(size * sizeof(Byte_t));
  registration_request_buf = initialNasMsg->data;

  initialNasMsg->length = mm_msg_encode(mm_msg, (uint8_t*)(initialNasMsg->data), size);
  registration_request_len = initialNasMsg->length;

}

void generateIdentityResponse(as_nas_info_t *initialNasMsg, uint8_t identitytype, uicc_t* uicc) {
  int size = sizeof(mm_msg_header_t);
  fgs_nas_message_t nas_msg;
  memset(&nas_msg, 0, sizeof(fgs_nas_message_t));
  MM_msg *mm_msg;

  mm_msg = &nas_msg.plain.mm_msg;
  // set header
  mm_msg->header.ex_protocol_discriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  mm_msg->header.security_header_type = PLAIN_5GS_MSG;
  mm_msg->header.message_type = FGS_IDENTITY_RESPONSE;


  // set identity response
  mm_msg->fgs_identity_response.protocoldiscriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  size += 1;
  mm_msg->fgs_identity_response.securityheadertype = PLAIN_5GS_MSG;
  size += 1;
  mm_msg->fgs_identity_response.messagetype = FGS_IDENTITY_RESPONSE;
  size += 1;
  if(identitytype == FGS_MOBILE_IDENTITY_SUCI){
    mm_msg->fgs_identity_response.fgsmobileidentity.suci.typeofidentity = FGS_MOBILE_IDENTITY_SUCI;
    mm_msg->fgs_identity_response.fgsmobileidentity.suci.mncdigit1 =
      uicc->nmc_size==2 ? uicc->imsiStr[3]-'0' :  uicc->imsiStr[4]-'0';
    mm_msg->fgs_identity_response.fgsmobileidentity.suci.mncdigit2 =
      uicc->nmc_size==2 ? uicc->imsiStr[4]-'0' :  uicc->imsiStr[5]-'0';
    mm_msg->fgs_identity_response.fgsmobileidentity.suci.mncdigit3 =
      uicc->nmc_size==2? 0xF : uicc->imsiStr[3]-'0';
    mm_msg->fgs_identity_response.fgsmobileidentity.suci.mccdigit1 = uicc->imsiStr[0]-'0';
    mm_msg->fgs_identity_response.fgsmobileidentity.suci.mccdigit2 = uicc->imsiStr[1]-'0';
    mm_msg->fgs_identity_response.fgsmobileidentity.suci.mccdigit3 = uicc->imsiStr[2]-'0';
    memcpy(mm_msg->registration_request.fgsmobileidentity.suci.schemeoutput, uicc->imsiStr+3+uicc->nmc_size, strlen(uicc->imsiStr) - (3+uicc->nmc_size));
    size += sizeof(Suci5GSMobileIdentity_t);
  }

  // encode the message
  initialNasMsg->data = (Byte_t *)malloc(size * sizeof(Byte_t));

  initialNasMsg->length = mm_msg_encode(mm_msg, (uint8_t*)(initialNasMsg->data), size);

}

static void generateAuthenticationResp(int Mod_id,as_nas_info_t *initialNasMsg, uint8_t *buf, uicc_t *uicc){

  derive_ue_keys(Mod_id,buf,uicc);
  OctetString res;
  res.length = 16;
  res.value = calloc(1,16);
  memcpy(res.value,ue_security_key[Mod_id]->res,16);

  int size = sizeof(mm_msg_header_t);
  fgs_nas_message_t nas_msg;
  memset(&nas_msg, 0, sizeof(fgs_nas_message_t));
  MM_msg *mm_msg;

  mm_msg = &nas_msg.plain.mm_msg;
  // set header
  mm_msg->header.ex_protocol_discriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  mm_msg->header.security_header_type = PLAIN_5GS_MSG;
  mm_msg->header.message_type = FGS_AUTHENTICATION_RESPONSE;

  // set authentication response
  mm_msg->fgs_identity_response.protocoldiscriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  size += 1;
  mm_msg->fgs_identity_response.securityheadertype = PLAIN_5GS_MSG;
  size += 1;
  mm_msg->fgs_identity_response.messagetype = FGS_AUTHENTICATION_RESPONSE;
  size += 1;

  //set response parameter
  mm_msg->fgs_auth_response.authenticationresponseparameter.res = res;
  size += 18;
  // encode the message
  initialNasMsg->data = (Byte_t *)malloc(size * sizeof(Byte_t));

  initialNasMsg->length = mm_msg_encode(mm_msg, (uint8_t*)(initialNasMsg->data), size);
}

int nas_itti_kgnb_refresh_req(const uint8_t kgnb[32], int instance) {
  MessageDef *message_p;
  message_p = itti_alloc_new_message(TASK_NAS_NRUE, 0, NAS_KENB_REFRESH_REQ);
  memcpy(NAS_KENB_REFRESH_REQ(message_p).kenb, kgnb, sizeof(NAS_KENB_REFRESH_REQ(message_p).kenb));
  return itti_send_msg_to_task(TASK_RRC_NRUE, instance, message_p);
}

static void generateSecurityModeComplete(int Mod_id,as_nas_info_t *initialNasMsg)
{
  int size = sizeof(mm_msg_header_t);
  fgs_nas_message_t nas_msg;
  memset(&nas_msg, 0, sizeof(fgs_nas_message_t));

  MM_msg *mm_msg;
  nas_stream_cipher_t stream_cipher;
  uint8_t             mac[4];
  // set security protected header
  nas_msg.header.protocol_discriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  nas_msg.header.security_header_type = INTEGRITY_PROTECTED_AND_CIPHERED_WITH_NEW_SECU_CTX;
  size += 7;

  mm_msg = &nas_msg.security_protected.plain.mm_msg;

  // set header
  mm_msg->header.ex_protocol_discriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  mm_msg->header.security_header_type = PLAIN_5GS_MSG;
  mm_msg->header.message_type = FGS_SECURITY_MODE_COMPLETE;

  // set security mode complete
  mm_msg->fgs_security_mode_complete.protocoldiscriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  size += 1;
  mm_msg->fgs_security_mode_complete.securityheadertype    = PLAIN_5GS_MSG;
  size += 1;
  mm_msg->fgs_security_mode_complete.messagetype           = FGS_SECURITY_MODE_COMPLETE;
  size += 1;

  mm_msg->fgs_security_mode_complete.fgsmobileidentity.imeisv.typeofidentity = FGS_MOBILE_IDENTITY_IMEISV;
  mm_msg->fgs_security_mode_complete.fgsmobileidentity.imeisv.digit1  = 1;
  mm_msg->fgs_security_mode_complete.fgsmobileidentity.imeisv.digitp1 = 1;
  mm_msg->fgs_security_mode_complete.fgsmobileidentity.imeisv.digitp  = 1;
  mm_msg->fgs_security_mode_complete.fgsmobileidentity.imeisv.oddeven = 0;
  size += 5;

  mm_msg->fgs_security_mode_complete.fgsnasmessagecontainer.nasmessagecontainercontents.value  = registration_request_buf;
  mm_msg->fgs_security_mode_complete.fgsnasmessagecontainer.nasmessagecontainercontents.length = registration_request_len;
  size += (registration_request_len + 2);

  // encode the message
  initialNasMsg->data = (Byte_t *)malloc(size * sizeof(Byte_t));

  int security_header_len = nas_protected_security_header_encode((char*)(initialNasMsg->data),&(nas_msg.header), size);

  initialNasMsg->length = security_header_len + mm_msg_encode(mm_msg, (uint8_t*)(initialNasMsg->data+security_header_len), size-security_header_len);

  stream_cipher.key        = ue_security_key[Mod_id]->knas_int;
  stream_cipher.key_length = 16;
  stream_cipher.count      = 0;
  stream_cipher.bearer     = 1;
  stream_cipher.direction  = 0;
  stream_cipher.message    = (unsigned char *)(initialNasMsg->data + 6);
  /* length in bits */
  stream_cipher.blength    = (initialNasMsg->length - 6) << 3;

  // only for Type of integrity protection algorithm: 128-5G-IA2 (2)
  nas_stream_encrypt_eia2(
    &stream_cipher,
    mac);

  printf("mac %x %x %x %x \n", mac[0], mac[1], mac[2], mac[3]);
  for(int i = 0; i < 4; i++){
     initialNasMsg->data[2+i] = mac[i];
  }
}

static void generateRegistrationComplete(int Mod_id, as_nas_info_t *initialNasMsg, SORTransparentContainer               *sortransparentcontainer) {
  //wait send RRCReconfigurationComplete and InitialContextSetupResponse
  sleep(1);
  int length = 0;
  int size = 0;
  fgs_nas_message_t nas_msg;
  nas_stream_cipher_t stream_cipher;
  uint8_t             mac[4];
  memset(&nas_msg, 0, sizeof(fgs_nas_message_t));
  fgs_nas_message_security_protected_t *sp_msg;

  sp_msg = &nas_msg.security_protected;
  // set header
  sp_msg->header.protocol_discriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  sp_msg->header.security_header_type   = INTEGRITY_PROTECTED_AND_CIPHERED;
  sp_msg->header.message_authentication_code = 0;
  sp_msg->header.sequence_number        = 1;
  length = 7;
  sp_msg->plain.mm_msg.registration_complete.protocoldiscriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  length += 1;
  sp_msg->plain.mm_msg.registration_complete.securityheadertype    = PLAIN_5GS_MSG;
  sp_msg->plain.mm_msg.registration_complete.sparehalfoctet        = 0;
  length += 1;
  sp_msg->plain.mm_msg.registration_complete.messagetype = REGISTRATION_COMPLETE;
  length += 1;

  if(sortransparentcontainer) {
    length += sortransparentcontainer->sortransparentcontainercontents.length;
  }

  // encode the message
  initialNasMsg->data = (Byte_t *)malloc(length * sizeof(Byte_t));

  /* Encode the first octet of the header (extended protocol discriminator) */
  ENCODE_U8(initialNasMsg->data + size, sp_msg->header.protocol_discriminator, size);
  
  /* Encode the security header type */
  ENCODE_U8(initialNasMsg->data + size, sp_msg->header.security_header_type, size);
  
  /* Encode the message authentication code */
  ENCODE_U32(initialNasMsg->data + size, sp_msg->header.message_authentication_code, size);
  
  /* Encode the sequence number */
  ENCODE_U8(initialNasMsg->data + size, sp_msg->header.sequence_number, size);
  
  
  /* Encode the extended protocol discriminator */
  ENCODE_U8(initialNasMsg->data + size, sp_msg->plain.mm_msg.registration_complete.protocoldiscriminator, size);
    
  /* Encode the security header type */
  ENCODE_U8(initialNasMsg->data + size, sp_msg->plain.mm_msg.registration_complete.securityheadertype, size);
    
  /* Encode the message type */
  ENCODE_U8(initialNasMsg->data + size, sp_msg->plain.mm_msg.registration_complete.messagetype, size);

  if(sortransparentcontainer) {
    encode_registration_complete(&sp_msg->plain.mm_msg.registration_complete, initialNasMsg->data + size, length - size);
  }
  
  initialNasMsg->length = length;
  stream_cipher.key        = ue_security_key[Mod_id]->knas_int;
  stream_cipher.key_length = 16;
  stream_cipher.count      = 1;
  stream_cipher.bearer     = 1;
  stream_cipher.direction  = 0;
  stream_cipher.message    = (unsigned char *)(initialNasMsg->data + 6);
  /* length in bits */
  stream_cipher.blength    = (initialNasMsg->length - 6) << 3;

  // only for Type of integrity protection algorithm: 128-5G-IA2 (2)
  nas_stream_encrypt_eia2(
    &stream_cipher,
    mac);

  printf("mac %x %x %x %x \n", mac[0], mac[1], mac[2], mac[3]);
  for(int i = 0; i < 4; i++){
     initialNasMsg->data[2+i] = mac[i];
  }
}

void decodeDownlinkNASTransport(as_nas_info_t *initialNasMsg, uint8_t * pdu_buffer){
  uint8_t msg_type = *(pdu_buffer + 16);
  if(msg_type == FGS_PDU_SESSION_ESTABLISHMENT_ACC){
    sprintf(baseNetAddress, "%d.%d", *(pdu_buffer + 39),*(pdu_buffer + 40));
    int third_octet = *(pdu_buffer + 41);
    int fourth_octet = *(pdu_buffer + 42);
    LOG_A(NAS, "Received PDU Session Establishment Accept\n");
    nas_config(1,third_octet,fourth_octet,"ue");
  } else {
    LOG_E(NAS, "Received unexpected message in DLinformationTransfer %d\n", msg_type);
  }
}

static void generatePduSessionEstablishRequest(int Mod_id, uicc_t * uicc, as_nas_info_t *initialNasMsg){
  //wait send RegistrationComplete
  usleep(100*150);
  int size = 0;
  fgs_nas_message_t nas_msg={0};

  // setup pdu session establishment request
  uint16_t req_length = 7;
  uint8_t *req_buffer = malloc(req_length);
  pdu_session_establishment_request_msg pdu_session_establish;
  pdu_session_establish.protocoldiscriminator = FGS_SESSION_MANAGEMENT_MESSAGE;
  pdu_session_establish.pdusessionid = 10;
  pdu_session_establish.pti = 1;
  pdu_session_establish.pdusessionestblishmsgtype = FGS_PDU_SESSION_ESTABLISHMENT_REQ;
  pdu_session_establish.maxdatarate = 0xffff;
  pdu_session_establish.pdusessiontype = 0x91;
  encode_pdu_session_establishment_request(&pdu_session_establish, req_buffer);



  MM_msg *mm_msg;
  nas_stream_cipher_t stream_cipher;
  uint8_t             mac[4];
  nas_msg.header.protocol_discriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  nas_msg.header.security_header_type = INTEGRITY_PROTECTED_AND_CIPHERED_WITH_NEW_SECU_CTX;
  size += 7;

  mm_msg = &nas_msg.security_protected.plain.mm_msg;

  // set header
  mm_msg->header.ex_protocol_discriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  mm_msg->header.security_header_type = PLAIN_5GS_MSG;
  mm_msg->header.message_type = FGS_UPLINK_NAS_TRANSPORT;

  // set uplink nas transport
  mm_msg->uplink_nas_transport.protocoldiscriminator = FGS_MOBILITY_MANAGEMENT_MESSAGE;
  size += 1;
  mm_msg->uplink_nas_transport.securityheadertype    = PLAIN_5GS_MSG;
  size += 1;
  mm_msg->uplink_nas_transport.messagetype = FGS_UPLINK_NAS_TRANSPORT;
  size += 1;

  mm_msg->uplink_nas_transport.payloadcontainertype.iei = 0;
  mm_msg->uplink_nas_transport.payloadcontainertype.type = 1;
  size += 1;
  mm_msg->uplink_nas_transport.fgspayloadcontainer.payloadcontainercontents.length = req_length;
  mm_msg->uplink_nas_transport.fgspayloadcontainer.payloadcontainercontents.value = req_buffer;
  size += (2+req_length);
  mm_msg->uplink_nas_transport.pdusessionid = 10;
  mm_msg->uplink_nas_transport.requesttype = 1;
  size += 3;
  const bool has_nssai_sd = uicc->nssai_sd != 0xffffff; // 0xffffff means "no SD", TS 23.003
  const size_t nssai_len = has_nssai_sd ? 4 : 1;
  mm_msg->uplink_nas_transport.snssai.length = nssai_len;
  //Fixme: it seems there are a lot of memory errors in this: this value was on the stack, 
  // but pushed  in a itti message to another thread
  // this kind of error seems in many places in 5G NAS
  mm_msg->uplink_nas_transport.snssai.value = calloc(1, nssai_len);
  mm_msg->uplink_nas_transport.snssai.value[0] = uicc->nssai_sst;
  if (has_nssai_sd) {
    mm_msg->uplink_nas_transport.snssai.value[1] = (uicc->nssai_sd >> 16) & 0xFF;
    mm_msg->uplink_nas_transport.snssai.value[2] = (uicc->nssai_sd >> 8)  & 0xFF;
    mm_msg->uplink_nas_transport.snssai.value[3] = (uicc->nssai_sd)       & 0xFF;
  }
  size += 1 + 1 + nssai_len;
  int dnnSize=strlen(uicc->dnnStr);
  mm_msg->uplink_nas_transport.dnn.value=calloc(1,dnnSize+1);
  mm_msg->uplink_nas_transport.dnn.length = dnnSize + 1;
  mm_msg->uplink_nas_transport.dnn.value[0] = dnnSize + 1;
  memcpy(mm_msg->uplink_nas_transport.dnn.value+1,uicc->dnnStr, dnnSize);
  size += (1+1+dnnSize+1);

  // encode the message
  initialNasMsg->data = (Byte_t *)malloc(size * sizeof(Byte_t));
  int security_header_len = nas_protected_security_header_encode((char*)(initialNasMsg->data),&(nas_msg.header), size);

  initialNasMsg->length = security_header_len + mm_msg_encode(mm_msg, (uint8_t*)(initialNasMsg->data+security_header_len), size-security_header_len);

  stream_cipher.key        = ue_security_key[Mod_id]->knas_int;
  stream_cipher.key_length = 16;
  stream_cipher.count      = 0;
  stream_cipher.bearer     = 1;
  stream_cipher.direction  = 0;
  stream_cipher.message    = (unsigned char *)(initialNasMsg->data + 6);
  /* length in bits */
  stream_cipher.blength    = (initialNasMsg->length - 6) << 3;

  // only for Type of integrity protection algorithm: 128-5G-IA2 (2)
  nas_stream_encrypt_eia2(
    &stream_cipher,
    mac);

  printf("mac %x %x %x %x \n", mac[0], mac[1], mac[2], mac[3]);
  for(int i = 0; i < 4; i++){
     initialNasMsg->data[2+i] = mac[i];
  }
}


uint8_t get_msg_type(uint8_t *pdu_buffer, uint32_t length) {
  uint8_t          msg_type = 0;
  uint8_t          offset   = 0;

  if ((pdu_buffer != NULL) && (length > 0)) {
    if (((nas_msg_header_t *)(pdu_buffer))->choice.security_protected_nas_msg_header_t.security_header_type > 0) {
      offset += SECURITY_PROTECTED_5GS_NAS_MESSAGE_HEADER_LENGTH;
      if (offset < length) {
        msg_type = ((mm_msg_header_t *)(pdu_buffer + offset))->message_type;

        if (msg_type == FGS_DOWNLINK_NAS_TRANSPORT) {
          msg_type = ((dl_nas_transport_t *)(pdu_buffer+ offset))->sm_nas_msg_header.message_type;
        }
      }
    } else { // plain 5GS NAS message
      msg_type = ((nas_msg_header_t *)(pdu_buffer))->choice.plain_nas_msg_header.message_type;
    }
  } else {
    LOG_I(NAS, "[UE] Received invalid downlink message\n");
  }

  return msg_type;
}

void *nas_nrue_task(void *args_p)
{
  MessageDef           *msg_p;
  instance_t            instance;
  unsigned int          Mod_id;
  int                   result;
  uint8_t               msg_type = 0;
  uint8_t              *pdu_buffer = NULL;


  ue_security_key=(ue_sa_security_key_t **)calloc(1,sizeof(ue_sa_security_key_t*)*NB_UE_INST);
  itti_mark_task_ready (TASK_NAS_NRUE);
  
  while(1) {
    // Wait for a message or an event
    itti_receive_msg (TASK_NAS_NRUE, &msg_p);

    if (msg_p != NULL) {
      instance = msg_p->ittiMsgHeader.originInstance;
      Mod_id = instance ;
      uicc_t *uicc=checkUicc(Mod_id);

      if (instance == INSTANCE_DEFAULT) {
        printf("%s:%d: FATAL: instance is INSTANCE_DEFAULT, should not happen.\n",
               __FILE__, __LINE__);
        exit_fun("exit... \n");
      }

      switch (ITTI_MSG_ID(msg_p)) {
      case INITIALIZE_MESSAGE:
        LOG_I(NAS, "[UE %d] Received %s\n", Mod_id,  ITTI_MSG_NAME (msg_p));

        break;

      case TERMINATE_MESSAGE:
        itti_exit_task ();
        break;

      case MESSAGE_TEST:
        LOG_I(NAS, "[UE %d] Received %s\n", Mod_id,  ITTI_MSG_NAME (msg_p));
        break;

      case NAS_CELL_SELECTION_CNF:
        LOG_I(NAS, "[UE %d] Received %s: errCode %u, cellID %u, tac %u\n", Mod_id,  ITTI_MSG_NAME (msg_p),
              NAS_CELL_SELECTION_CNF (msg_p).errCode, NAS_CELL_SELECTION_CNF (msg_p).cellID, NAS_CELL_SELECTION_CNF (msg_p).tac);
        // as_stmsi_t s_tmsi={0, 0};
        // as_nas_info_t nas_info;
        // plmn_t plmnID={0, 0, 0, 0};
        // generateRegistrationRequest(&nas_info);
        // nr_nas_itti_nas_establish_req(0, AS_TYPE_ORIGINATING_SIGNAL, s_tmsi, plmnID, nas_info.data, nas_info.length, 0);
        break;

      case NAS_CELL_SELECTION_IND:
        LOG_I(NAS, "[UE %d] Received %s: cellID %u, tac %u\n", Mod_id,  ITTI_MSG_NAME (msg_p),
              NAS_CELL_SELECTION_IND (msg_p).cellID, NAS_CELL_SELECTION_IND (msg_p).tac);

        /* TODO not processed by NAS currently */
        break;

      case NAS_PAGING_IND:
        LOG_I(NAS, "[UE %d] Received %s: cause %u\n", Mod_id,  ITTI_MSG_NAME (msg_p),
              NAS_PAGING_IND (msg_p).cause);

        /* TODO not processed by NAS currently */
        break;

      case NAS_CONN_ESTABLI_CNF:
      {
        LOG_I(NAS, "[UE %d] Received %s: errCode %u, length %u\n", Mod_id,  ITTI_MSG_NAME (msg_p),
              NAS_CONN_ESTABLI_CNF (msg_p).errCode, NAS_CONN_ESTABLI_CNF (msg_p).nasMsg.length);

        pdu_buffer = NAS_CONN_ESTABLI_CNF (msg_p).nasMsg.data;
        msg_type = get_msg_type(pdu_buffer, NAS_CONN_ESTABLI_CNF (msg_p).nasMsg.length);

        if(msg_type == REGISTRATION_ACCEPT){
          LOG_I(NAS, "[UE] Received REGISTRATION ACCEPT message\n");

          as_nas_info_t initialNasMsg;
          memset(&initialNasMsg, 0, sizeof(as_nas_info_t));
          generateRegistrationComplete(Mod_id,&initialNasMsg, NULL);
          if(initialNasMsg.length > 0){
            MessageDef *message_p;
            message_p = itti_alloc_new_message(TASK_NAS_NRUE, 0, NAS_UPLINK_DATA_REQ);
            NAS_UPLINK_DATA_REQ(message_p).UEid          = Mod_id;
            NAS_UPLINK_DATA_REQ(message_p).nasMsg.data   = (uint8_t *)initialNasMsg.data;
            NAS_UPLINK_DATA_REQ(message_p).nasMsg.length = initialNasMsg.length;
            itti_send_msg_to_task(TASK_RRC_NRUE, instance, message_p);
            LOG_I(NAS, "Send NAS_UPLINK_DATA_REQ message(RegistrationComplete)\n");
          }

          as_nas_info_t pduEstablishMsg;
          memset(&pduEstablishMsg, 0, sizeof(as_nas_info_t));
          generatePduSessionEstablishRequest(Mod_id, uicc, &pduEstablishMsg);
          if(pduEstablishMsg.length > 0){
            MessageDef *message_p;
            message_p = itti_alloc_new_message(TASK_NAS_NRUE, 0, NAS_UPLINK_DATA_REQ);
            NAS_UPLINK_DATA_REQ(message_p).UEid          = Mod_id;
            NAS_UPLINK_DATA_REQ(message_p).nasMsg.data   = (uint8_t *)pduEstablishMsg.data;
            NAS_UPLINK_DATA_REQ(message_p).nasMsg.length = pduEstablishMsg.length;
            itti_send_msg_to_task(TASK_RRC_NRUE, instance, message_p);
            LOG_I(NAS, "Send NAS_UPLINK_DATA_REQ message(PduSessionEstablishRequest)\n");
          }
        } else if(msg_type == FGS_PDU_SESSION_ESTABLISHMENT_ACC){
          capture_pdu_session_establishment_accept_msg(pdu_buffer, NAS_CONN_ESTABLI_CNF (msg_p).nasMsg.length);
        }

        break;
      }

      case NAS_CONN_RELEASE_IND:
        LOG_I(NAS, "[UE %d] Received %s: cause %u\n", Mod_id, ITTI_MSG_NAME (msg_p),
              NAS_CONN_RELEASE_IND (msg_p).cause);

        break;

      case NAS_UPLINK_DATA_CNF:
        LOG_I(NAS, "[UE %d] Received %s: UEid %u, errCode %u\n", Mod_id, ITTI_MSG_NAME (msg_p),
              NAS_UPLINK_DATA_CNF (msg_p).UEid, NAS_UPLINK_DATA_CNF (msg_p).errCode);

        break;

      case NAS_DOWNLINK_DATA_IND:
      {
        LOG_I(NAS, "[UE %d] Received %s: UEid %u, length %u , buffer %p\n", Mod_id,
                                                                            ITTI_MSG_NAME (msg_p),
                                                                            Mod_id,
                                                                            NAS_DOWNLINK_DATA_IND(msg_p).nasMsg.length,
                                                                            NAS_DOWNLINK_DATA_IND(msg_p).nasMsg.data);
        as_nas_info_t initialNasMsg={0};

        pdu_buffer = NAS_DOWNLINK_DATA_IND(msg_p).nasMsg.data;
        msg_type = get_msg_type(pdu_buffer, NAS_DOWNLINK_DATA_IND(msg_p).nasMsg.length);

        switch(msg_type){

          case FGS_IDENTITY_REQUEST:
	            generateIdentityResponse(&initialNasMsg,*(pdu_buffer+3), uicc);
              break;
          case FGS_AUTHENTICATION_REQUEST:
	            generateAuthenticationResp(Mod_id,&initialNasMsg, pdu_buffer, uicc);
              break;
          case FGS_SECURITY_MODE_COMMAND:
            nas_itti_kgnb_refresh_req(ue_security_key[Mod_id]->kgnb, instance);
            generateSecurityModeComplete(Mod_id,&initialNasMsg);
            break;
          case FGS_DOWNLINK_NAS_TRANSPORT:
            decodeDownlinkNASTransport(&initialNasMsg, pdu_buffer);
            break;
	case FGS_PDU_SESSION_ESTABLISHMENT_ACC:
	  {
	    uint8_t offset = 0;
	    uint8_t *payload_container = pdu_buffer;
	    offset += SECURITY_PROTECTED_5GS_NAS_MESSAGE_HEADER_LENGTH;
	    uint16_t payload_container_length = htons(((dl_nas_transport_t *)(pdu_buffer + offset))->payload_container_length);
	    if ((payload_container_length >= PAYLOAD_CONTAINER_LENGTH_MIN) &&
		(payload_container_length <= PAYLOAD_CONTAINER_LENGTH_MAX))
	      offset += (PLAIN_5GS_NAS_MESSAGE_HEADER_LENGTH + 3);
	    if (offset < NAS_CONN_ESTABLI_CNF(msg_p).nasMsg.length) 
	      payload_container = pdu_buffer + offset;
	    
	    while(offset < payload_container_length) {
	      if (*(payload_container + offset) == 0x29) { // PDU address IEI
		if ((*(payload_container+offset+1) == 0x05) && (*(payload_container +offset+2) == 0x01)) { // IPV4
		  nas_getparams();
		  sprintf(baseNetAddress, "%d.%d", *(payload_container+offset+3), *(payload_container+offset+4));
		  int third_octet = *(payload_container+offset+5);
		  int fourth_octet = *(payload_container+offset+6);
		  LOG_I(NAS, "Received PDU Session Establishment Accept, UE IP: %d.%d.%d.%d\n",
			*(payload_container+offset+3), *(payload_container+offset+4),
			*(payload_container+offset+5), *(payload_container+offset+6));
		  nas_config(1,third_octet,fourth_octet,"oaitun_ue");
		  break;
		}
	      }
	      offset++;
	    }
	  }
	  break;
          default:
              LOG_W(NR_RRC,"unknow message type %d\n",msg_type);
              break;
        }

        if(initialNasMsg.length > 0){
          MessageDef *message_p;
          message_p = itti_alloc_new_message(TASK_NAS_NRUE, 0, NAS_UPLINK_DATA_REQ);
          NAS_UPLINK_DATA_REQ(message_p).UEid          = Mod_id;
          NAS_UPLINK_DATA_REQ(message_p).nasMsg.data   = (uint8_t *)initialNasMsg.data;

          NAS_UPLINK_DATA_REQ(message_p).nasMsg.length = initialNasMsg.length;
          itti_send_msg_to_task(TASK_RRC_NRUE, instance, message_p);
          LOG_I(NAS, "Send NAS_UPLINK_DATA_REQ message\n");
        }
      }
        break;

      default:
        LOG_E(NAS, "[UE %d] Received unexpected message %s\n", Mod_id,  ITTI_MSG_NAME (msg_p));
        break;
      }

      result = itti_free (ITTI_MSG_ORIGIN_ID(msg_p), msg_p);
      AssertFatal (result == EXIT_SUCCESS, "Failed to free memory (%d)!\n", result);
      msg_p = NULL;
    }
  }

  return NULL;
}
