/*
 * 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
 */

/*****************************************************************************
Source      EmmNull.c

Version     0.1

Date        2012/10/03

Product     NAS stack

Subsystem   EPS Mobility Management

Author      Frederic Maurel

Description Implements the EPS Mobility Management procedures executed
        when the EMM-SAP is in EMM-NULL state.

        In EMM-NULL state, the EPS capability is disabled in the UE.
        No EPS mobility management function shall be performed.

*****************************************************************************/


#include "emm_fsm.h"
#include "commonDef.h"
#include "nas_log.h"

#include "emm_proc.h"

#include <assert.h>

/****************************************************************************/
/****************  E X T E R N A L    D E F I N I T I O N S  ****************/
/****************************************************************************/

/****************************************************************************/
/*******************  L O C A L    D E F I N I T I O N S  *******************/
/****************************************************************************/

/****************************************************************************/
/******************  E X P O R T E D    F U N C T I O N S  ******************/
/****************************************************************************/

/****************************************************************************
 **                                                                        **
 ** Name:    EmmNull()                                                 **
 **                                                                        **
 ** Description: Handles the behaviour of the UE while the EMM-SAP is in   **
 **      EMM-NULL state.                                           **
 **                                                                        **
 ** Inputs:  evt:       The received EMM-SAP event                 **
 **      Others:    emm_fsm_status                             **
 **                                                                        **
 ** Outputs:     None                                                      **
 **      Return:    RETURNok, RETURNerror                      **
 **      Others:    emm_fsm_status                             **
 **                                                                        **
 ***************************************************************************/
int EmmNull(const emm_reg_t *evt)
{
  LOG_FUNC_IN;

  int rc;

  assert(emm_fsm_get_status() == EMM_NULL);

  /* Delete the authentication data RAND and RES */
  rc = emm_proc_authentication_delete();

  if (rc != RETURNok) {
    LOG_FUNC_RETURN (rc);
  }

  switch (evt->primitive) {
  case _EMMREG_S1_ENABLED:
    /*
     * The EPS capability has been enabled in the UE:
     * Move to the DEREGISTERED state;
     */
    rc = emm_fsm_set_status(EMM_DEREGISTERED);

    /*
     * And initialize the EMM procedure call manager in order to
     * establish an EMM context and make the UE reachable by an MME.
     */
    if (rc != RETURNerror) {
      rc = emm_proc_initialize();
    }

    break;

  default:
    rc = RETURNerror;
    LOG_TRACE(ERROR, "EMM-FSM   - Primitive is not valid (%d)",
              evt->primitive);
    LOG_TRACE(WARNING, "EMM-FSM   - Set phone functionnality to "
              "enable EPS capability (+cfun=1)");
    break;
  }

  LOG_FUNC_RETURN (rc);
}

/****************************************************************************/
/*********************  L O C A L    F U N C T I O N S  *********************/
/****************************************************************************/

