/*
 * 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 1.0  (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
 */

/*
                                enb_app.c
                             -------------------
  AUTHOR  : Laurent Winckel, Sebastien ROUX, Lionel GAUTHIER, Navid Nikaein
  COMPANY : EURECOM
  EMAIL   : Lionel.Gauthier@eurecom.fr and Navid Nikaein
*/

#include <string.h>
#include <stdio.h>

#include "enb_app.h"
#include "enb_config.h"
#include "assertions.h"

#include "log.h"
#if defined(OAI_EMU)
# include "OCG.h"
# include "OCG_extern.h"
#endif

#if defined(ENABLE_ITTI)
# include "intertask_interface.h"
# include "timer.h"
# if defined(ENABLE_USE_MME)
#   include "s1ap_eNB.h"
#   include "sctp_eNB_task.h"
#   include "gtpv1u_eNB_task.h"
# endif

extern unsigned char NB_eNB_INST;
#endif

#if defined(ENABLE_ITTI)

/*------------------------------------------------------------------------------*/
# if defined(ENABLE_USE_MME)
#   define ENB_REGISTER_RETRY_DELAY 10
# endif

/*------------------------------------------------------------------------------*/
static void configure_phy(module_id_t enb_id, const Enb_properties_array_t* enb_properties)
{
  MessageDef *msg_p;
  int CC_id;

  msg_p = itti_alloc_new_message (TASK_ENB_APP, PHY_CONFIGURATION_REQ);

  for (CC_id=0; CC_id<MAX_NUM_CCs; CC_id++) {
    PHY_CONFIGURATION_REQ (msg_p).frame_type[CC_id]              = enb_properties->properties[enb_id]->frame_type[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).prefix_type[CC_id]             = enb_properties->properties[enb_id]->prefix_type[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).downlink_frequency[CC_id]      = enb_properties->properties[enb_id]->downlink_frequency[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).uplink_frequency_offset[CC_id] = enb_properties->properties[enb_id]->uplink_frequency_offset[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).nb_antennas_tx[CC_id]          = enb_properties->properties[enb_id]->nb_antennas_tx[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).nb_antennas_rx[CC_id]          = enb_properties->properties[enb_id]->nb_antennas_rx[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).tx_gain[CC_id]                 = enb_properties->properties[enb_id]->tx_gain[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).rx_gain[CC_id]                 = enb_properties->properties[enb_id]->rx_gain[CC_id];
  }

  itti_send_msg_to_task (TASK_PHY_ENB, ENB_MODULE_ID_TO_INSTANCE(enb_id), msg_p);
}

/*------------------------------------------------------------------------------*/
static void configure_rrc(uint32_t enb_id, const Enb_properties_array_t *enb_properties)
{
  MessageDef *msg_p = NULL;
  int CC_id;

  msg_p = itti_alloc_new_message (TASK_ENB_APP, RRC_CONFIGURATION_REQ);

  RRC_CONFIGURATION_REQ (msg_p).cell_identity =   enb_properties->properties[enb_id]->eNB_id;
  RRC_CONFIGURATION_REQ (msg_p).tac =             enb_properties->properties[enb_id]->tac;
  RRC_CONFIGURATION_REQ (msg_p).mcc =             enb_properties->properties[enb_id]->mcc;
  RRC_CONFIGURATION_REQ (msg_p).mnc =             enb_properties->properties[enb_id]->mnc;
  RRC_CONFIGURATION_REQ (msg_p).mnc_digit_length = enb_properties->properties[enb_id]->mnc_digit_length;

  for (CC_id=0; CC_id<MAX_NUM_CCs; CC_id++) {
    RRC_CONFIGURATION_REQ (msg_p).frame_type[CC_id]                               = enb_properties->properties[enb_id]->frame_type[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).tdd_config[CC_id]                               = enb_properties->properties[enb_id]->tdd_config[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).tdd_config_s[CC_id]                             = enb_properties->properties[enb_id]->tdd_config_s[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).eutra_band[CC_id]                               = enb_properties->properties[enb_id]->eutra_band[CC_id];

    // RACH-Config
    RRC_CONFIGURATION_REQ (msg_p).rach_numberOfRA_Preambles[CC_id]                = enb_properties->properties[enb_id]->rach_numberOfRA_Preambles[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_preamblesGroupAConfig[CC_id]               = enb_properties->properties[enb_id]->rach_preamblesGroupAConfig[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_sizeOfRA_PreamblesGroupA[CC_id]            = enb_properties->properties[enb_id]->rach_sizeOfRA_PreamblesGroupA[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_messageSizeGroupA[CC_id]                   = enb_properties->properties[enb_id]->rach_messageSizeGroupA[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_messagePowerOffsetGroupB[CC_id]            = enb_properties->properties[enb_id]->rach_messagePowerOffsetGroupB[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_powerRampingStep[CC_id]                    = enb_properties->properties[enb_id]->rach_powerRampingStep[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_preambleInitialReceivedTargetPower[CC_id]  = enb_properties->properties[enb_id]->rach_preambleInitialReceivedTargetPower[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_preambleTransMax[CC_id]                    = enb_properties->properties[enb_id]->rach_preambleTransMax[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_raResponseWindowSize[CC_id]                = enb_properties->properties[enb_id]->rach_raResponseWindowSize[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_macContentionResolutionTimer[CC_id]        = enb_properties->properties[enb_id]->rach_macContentionResolutionTimer[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).rach_maxHARQ_Msg3Tx[CC_id]                      = enb_properties->properties[enb_id]->rach_maxHARQ_Msg3Tx[CC_id];

    // BCCH-Config
    RRC_CONFIGURATION_REQ (msg_p).bcch_modificationPeriodCoeff[CC_id]             = enb_properties->properties[enb_id]->bcch_modificationPeriodCoeff[CC_id];

    // PCCH-Config
    RRC_CONFIGURATION_REQ (msg_p).pcch_defaultPagingCycle[CC_id]                  = enb_properties->properties[enb_id]->pcch_defaultPagingCycle[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pcch_nB[CC_id]                                  = enb_properties->properties[enb_id]->pcch_nB[CC_id];

    // PRACH-Config
    RRC_CONFIGURATION_REQ (msg_p).prach_root[CC_id]                               = enb_properties->properties[enb_id]->prach_root[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).prach_config_index[CC_id]                       = enb_properties->properties[enb_id]->prach_config_index[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).prach_high_speed[CC_id]                         = enb_properties->properties[enb_id]->prach_high_speed[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).prach_zero_correlation[CC_id]                   = enb_properties->properties[enb_id]->prach_zero_correlation[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).prach_freq_offset[CC_id]                        = enb_properties->properties[enb_id]->prach_freq_offset[CC_id];

    // PDSCH-Config
    RRC_CONFIGURATION_REQ (msg_p).pdsch_referenceSignalPower[CC_id]               = enb_properties->properties[enb_id]->pdsch_referenceSignalPower[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pdsch_p_b[CC_id]                                = enb_properties->properties[enb_id]->pdsch_p_b[CC_id];

    // PUSCH-Config
    RRC_CONFIGURATION_REQ (msg_p).pusch_n_SB[CC_id]                               = enb_properties->properties[enb_id]->pusch_n_SB[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pusch_hoppingMode[CC_id]                        = enb_properties->properties[enb_id]->pusch_hoppingMode[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pusch_hoppingOffset[CC_id]                      = enb_properties->properties[enb_id]->pusch_hoppingOffset[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pusch_enable64QAM[CC_id]                        = enb_properties->properties[enb_id]->pusch_enable64QAM[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pusch_groupHoppingEnabled[CC_id]                = enb_properties->properties[enb_id]->pusch_groupHoppingEnabled[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pusch_groupAssignment[CC_id]                    = enb_properties->properties[enb_id]->pusch_groupAssignment[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pusch_sequenceHoppingEnabled[CC_id]             = enb_properties->properties[enb_id]->pusch_sequenceHoppingEnabled[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pusch_nDMRS1[CC_id]                             = enb_properties->properties[enb_id]->pusch_nDMRS1[CC_id];

    // PUCCH-Config

    RRC_CONFIGURATION_REQ (msg_p).pucch_delta_shift[CC_id]                        = enb_properties->properties[enb_id]->pucch_delta_shift[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pucch_nRB_CQI[CC_id]                            = enb_properties->properties[enb_id]->pucch_nRB_CQI[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pucch_nCS_AN[CC_id]                             = enb_properties->properties[enb_id]->pucch_nCS_AN[CC_id];
#ifndef Rel10
    RRC_CONFIGURATION_REQ (msg_p).pucch_n1_AN[CC_id]                              = enb_properties->properties[enb_id]->pucch_n1_AN[CC_id];
#endif

    // SRS Config
    RRC_CONFIGURATION_REQ (msg_p).srs_enable[CC_id]                               = enb_properties->properties[enb_id]->srs_enable[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).srs_BandwidthConfig[CC_id]                      = enb_properties->properties[enb_id]->srs_BandwidthConfig[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).srs_SubframeConfig[CC_id]                       = enb_properties->properties[enb_id]->srs_SubframeConfig[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).srs_ackNackST[CC_id]                            = enb_properties->properties[enb_id]->srs_ackNackST[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).srs_MaxUpPts[CC_id]                             = enb_properties->properties[enb_id]->srs_MaxUpPts[CC_id];

    // uplinkPowerControlCommon

    RRC_CONFIGURATION_REQ (msg_p).pusch_p0_Nominal[CC_id]                         = enb_properties->properties[enb_id]->pusch_p0_Nominal[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pucch_p0_Nominal[CC_id]                         = enb_properties->properties[enb_id]->pucch_p0_Nominal[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pusch_alpha[CC_id]                              = enb_properties->properties[enb_id]->pusch_alpha[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pucch_deltaF_Format1[CC_id]                     = enb_properties->properties[enb_id]->pucch_deltaF_Format1[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pucch_deltaF_Format1b[CC_id]                    = enb_properties->properties[enb_id]->pucch_deltaF_Format1b[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pucch_deltaF_Format2[CC_id]                     = enb_properties->properties[enb_id]->pucch_deltaF_Format2[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pucch_deltaF_Format2a[CC_id]                    = enb_properties->properties[enb_id]->pucch_deltaF_Format2a[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).pucch_deltaF_Format2b[CC_id]                    = enb_properties->properties[enb_id]->pucch_deltaF_Format2b[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).msg3_delta_Preamble[CC_id]                      = enb_properties->properties[enb_id]->msg3_delta_Preamble[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).ul_CyclicPrefixLength[CC_id]                    = enb_properties->properties[enb_id]->ul_CyclicPrefixLength[CC_id];

    // UE Timers and Constants

    RRC_CONFIGURATION_REQ (msg_p).ue_TimersAndConstants_t300[CC_id]               = enb_properties->properties[enb_id]->ue_TimersAndConstants_t300[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).ue_TimersAndConstants_t301[CC_id]               = enb_properties->properties[enb_id]->ue_TimersAndConstants_t301[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).ue_TimersAndConstants_t310[CC_id]               = enb_properties->properties[enb_id]->ue_TimersAndConstants_t310[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).ue_TimersAndConstants_n310[CC_id]               = enb_properties->properties[enb_id]->ue_TimersAndConstants_n310[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).ue_TimersAndConstants_t311[CC_id]               = enb_properties->properties[enb_id]->ue_TimersAndConstants_t311[CC_id];
    RRC_CONFIGURATION_REQ (msg_p).ue_TimersAndConstants_n311[CC_id]               = enb_properties->properties[enb_id]->ue_TimersAndConstants_n311[CC_id];

    RRC_CONFIGURATION_REQ (msg_p).ue_TransmissionMode[CC_id]                      = enb_properties->properties[enb_id]->ue_TransmissionMode[CC_id];

  }

  itti_send_msg_to_task (TASK_RRC_ENB, ENB_MODULE_ID_TO_INSTANCE(enb_id), msg_p);
}

/*------------------------------------------------------------------------------*/
# if defined(ENABLE_USE_MME)
static uint32_t eNB_app_register(uint32_t enb_id_start, uint32_t enb_id_end, const Enb_properties_array_t *enb_properties)
{
  uint32_t         enb_id;
  uint32_t         mme_id;
  MessageDef      *msg_p;
  uint32_t         register_enb_pending = 0;
  char            *str                  = NULL;
  struct in_addr   addr;

#   if defined(OAI_EMU)

#   endif

  for (enb_id = enb_id_start; (enb_id < enb_id_end) ; enb_id++) {
#   if defined(OAI_EMU)

    if (oai_emulation.info.cli_start_enb[enb_id] == 1)
#   endif
    {
      s1ap_register_enb_req_t *s1ap_register_eNB;

      /* note:  there is an implicit relationship between the data structure and the message name */
      msg_p = itti_alloc_new_message (TASK_ENB_APP, S1AP_REGISTER_ENB_REQ);

      s1ap_register_eNB = &S1AP_REGISTER_ENB_REQ(msg_p);

      /* Some default/random parameters */
      s1ap_register_eNB->eNB_id           = enb_properties->properties[enb_id]->eNB_id;
      s1ap_register_eNB->cell_type        = enb_properties->properties[enb_id]->cell_type;
      s1ap_register_eNB->eNB_name         = enb_properties->properties[enb_id]->eNB_name;
      s1ap_register_eNB->tac              = enb_properties->properties[enb_id]->tac;
      s1ap_register_eNB->mcc              = enb_properties->properties[enb_id]->mcc;
      s1ap_register_eNB->mnc              = enb_properties->properties[enb_id]->mnc;
      s1ap_register_eNB->mnc_digit_length = enb_properties->properties[enb_id]->mnc_digit_length;
      s1ap_register_eNB->default_drx      = enb_properties->properties[enb_id]->pcch_defaultPagingCycle[0];

      s1ap_register_eNB->nb_mme =         enb_properties->properties[enb_id]->nb_mme;
      AssertFatal (s1ap_register_eNB->nb_mme <= S1AP_MAX_NB_MME_IP_ADDRESS, "Too many MME for eNB %d (%d/%d)!", enb_id, s1ap_register_eNB->nb_mme,
                   S1AP_MAX_NB_MME_IP_ADDRESS);

      for (mme_id = 0; mme_id < s1ap_register_eNB->nb_mme; mme_id++) {
        s1ap_register_eNB->mme_ip_address[mme_id].ipv4 = enb_properties->properties[enb_id]->mme_ip_address[mme_id].ipv4;
        s1ap_register_eNB->mme_ip_address[mme_id].ipv6 = enb_properties->properties[enb_id]->mme_ip_address[mme_id].ipv6;
        strncpy (s1ap_register_eNB->mme_ip_address[mme_id].ipv4_address,
                 enb_properties->properties[enb_id]->mme_ip_address[mme_id].ipv4_address,
                 sizeof(s1ap_register_eNB->mme_ip_address[0].ipv4_address));
        strncpy (s1ap_register_eNB->mme_ip_address[mme_id].ipv6_address,
                 enb_properties->properties[enb_id]->mme_ip_address[mme_id].ipv6_address,
                 sizeof(s1ap_register_eNB->mme_ip_address[0].ipv6_address));
      }

      s1ap_register_eNB->sctp_in_streams       = enb_properties->properties[enb_id]->sctp_in_streams;
      s1ap_register_eNB->sctp_out_streams      = enb_properties->properties[enb_id]->sctp_out_streams;


      s1ap_register_eNB->enb_ip_address.ipv6 = 0;
      s1ap_register_eNB->enb_ip_address.ipv4 = 1;
      addr.s_addr = enb_properties->properties[enb_id]->enb_ipv4_address_for_S1_MME;
      str = inet_ntoa(addr);
      strcpy(s1ap_register_eNB->enb_ip_address.ipv4_address, str);

      LOG_I(ENB_APP,"[eNB %d] eNB_app_register for instance %d\n", enb_id, ENB_MODULE_ID_TO_INSTANCE(enb_id));

      itti_send_msg_to_task (TASK_S1AP, ENB_MODULE_ID_TO_INSTANCE(enb_id), msg_p);

      register_enb_pending++;
    }
  }

  return register_enb_pending;
}
# endif
#endif

/*------------------------------------------------------------------------------*/
void *eNB_app_task(void *args_p)
{
  const Enb_properties_array_t   *enb_properties_p  = NULL;
#if defined(ENABLE_ITTI)
  uint32_t                        enb_nb = 1; /* Default number of eNB is 1 */
  uint32_t                        enb_id_start = 0;
  uint32_t                        enb_id_end = enb_id_start + enb_nb;
# if defined(ENABLE_USE_MME)
  uint32_t                        register_enb_pending;
  uint32_t                        registered_enb;
  long                            enb_register_retry_timer_id;
# endif
  uint32_t                        enb_id;
  MessageDef                     *msg_p           = NULL;
  const char                     *msg_name        = NULL;
  instance_t                      instance;
  int                             result;

  /* for no gcc warnings */
  (void)instance;

  itti_mark_task_ready (TASK_ENB_APP);

# if defined(ENABLE_USE_MME)
#   if defined(OAI_EMU)
  enb_nb =        oai_emulation.info.nb_enb_local;
  enb_id_start =  oai_emulation.info.first_enb_local;
  enb_id_end =    oai_emulation.info.first_enb_local + enb_nb;

  AssertFatal (enb_id_end <= NUMBER_OF_eNB_MAX,
               "Last eNB index is greater or equal to maximum eNB index (%d/%d)!",
               enb_id_end, NUMBER_OF_eNB_MAX);
#   endif
# endif

  enb_properties_p = enb_config_get();

  AssertFatal (enb_nb <= enb_properties_p->number,
               "Number of eNB is greater than eNB defined in configuration file (%d/%d)!",
               enb_nb, enb_properties_p->number);

  for (enb_id = enb_id_start; (enb_id < enb_id_end) ; enb_id++) {
    configure_phy(enb_id, enb_properties_p);
    configure_rrc(enb_id, enb_properties_p);
  }

# if defined(ENABLE_USE_MME)
  /* Try to register each eNB */
  registered_enb = 0;
  register_enb_pending = eNB_app_register (enb_id_start, enb_id_end, enb_properties_p);
# else
  /* Start L2L1 task */
  msg_p = itti_alloc_new_message(TASK_ENB_APP, INITIALIZE_MESSAGE);
  itti_send_msg_to_task(TASK_L2L1, INSTANCE_DEFAULT, msg_p);
# endif

  do {
    // Wait for a message
    itti_receive_msg (TASK_ENB_APP, &msg_p);

    msg_name = ITTI_MSG_NAME (msg_p);
    instance = ITTI_MSG_INSTANCE (msg_p);

    switch (ITTI_MSG_ID(msg_p)) {
    case TERMINATE_MESSAGE:
      itti_exit_task ();
      break;

    case MESSAGE_TEST:
      LOG_I(ENB_APP, "Received %s\n", ITTI_MSG_NAME(msg_p));
      break;

# if defined(ENABLE_USE_MME)

    case S1AP_REGISTER_ENB_CNF:
      LOG_I(ENB_APP, "[eNB %d] Received %s: associated MME %d\n", instance, msg_name,
            S1AP_REGISTER_ENB_CNF(msg_p).nb_mme);

      DevAssert(register_enb_pending > 0);
      register_enb_pending--;

      /* Check if at least eNB is registered with one MME */
      if (S1AP_REGISTER_ENB_CNF(msg_p).nb_mme > 0) {
        registered_enb++;
      }

      /* Check if all register eNB requests have been processed */
      if (register_enb_pending == 0) {
        if (registered_enb == enb_nb) {
          /* If all eNB are registered, start L2L1 task */
          MessageDef *msg_init_p;

          msg_init_p = itti_alloc_new_message (TASK_ENB_APP, INITIALIZE_MESSAGE);
          itti_send_msg_to_task (TASK_L2L1, INSTANCE_DEFAULT, msg_init_p);

#   if defined(OAI_EMU)

          /* Also inform all NAS UE tasks */
          for (instance = NB_eNB_INST + oai_emulation.info.first_ue_local;
               instance < (NB_eNB_INST + oai_emulation.info.first_ue_local + oai_emulation.info.nb_ue_local); instance ++) {
            msg_init_p = itti_alloc_new_message (TASK_ENB_APP, INITIALIZE_MESSAGE);
            itti_send_msg_to_task (TASK_NAS_UE, instance, msg_init_p);
          }

#   endif
        } else {
          uint32_t not_associated = enb_nb - registered_enb;

          LOG_W(ENB_APP, " %d eNB %s not associated with a MME, retrying registration in %d seconds ...\n",
                not_associated, not_associated > 1 ? "are" : "is", ENB_REGISTER_RETRY_DELAY);

          /* Restart the eNB registration process in ENB_REGISTER_RETRY_DELAY seconds */
          if (timer_setup (ENB_REGISTER_RETRY_DELAY, 0, TASK_ENB_APP, INSTANCE_DEFAULT, TIMER_ONE_SHOT,
                           NULL, &enb_register_retry_timer_id) < 0) {
            LOG_E(ENB_APP, " Can not start eNB register retry timer, use \"sleep\" instead!\n");

            sleep(ENB_REGISTER_RETRY_DELAY);
            /* Restart the registration process */
            registered_enb = 0;
            register_enb_pending = eNB_app_register (enb_id_start, enb_id_end, enb_properties_p);
          }
        }
      }

      break;

    case S1AP_DEREGISTERED_ENB_IND:
      LOG_W(ENB_APP, "[eNB %d] Received %s: associated MME %d\n", instance, msg_name,
            S1AP_DEREGISTERED_ENB_IND(msg_p).nb_mme);

      /* TODO handle recovering of registration */
      break;

    case TIMER_HAS_EXPIRED:
      LOG_I(ENB_APP, " Received %s: timer_id %d\n", msg_name, TIMER_HAS_EXPIRED(msg_p).timer_id);

      if (TIMER_HAS_EXPIRED (msg_p).timer_id == enb_register_retry_timer_id) {
        /* Restart the registration process */
        registered_enb = 0;
        register_enb_pending = eNB_app_register (enb_id_start, enb_id_end, enb_properties_p);
      }

      break;
# endif

    default:
      LOG_E(ENB_APP, "Received unexpected message %s\n", msg_name);
      break;
    }

    result = itti_free (ITTI_MSG_ORIGIN_ID(msg_p), msg_p);
    AssertFatal (result == EXIT_SUCCESS, "Failed to free memory (%d)!\n", result);
  } while (1);

#endif

  /* for no gcc warnings */
  (void)enb_properties_p;

  return NULL;
}
