/*******************************************************************************
    OpenAirInterface
    Copyright(c) 1999 - 2014 Eurecom

    OpenAirInterface 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 3 of the License, or
    (at your option) any later version.


    OpenAirInterface 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.

    You should have received a copy of the GNU General Public License
    along with OpenAirInterface.The full GNU General Public License is
   included in this distribution in the file called "COPYING". If not,
   see <http://www.gnu.org/licenses/>.

  Contact Information
  OpenAirInterface Admin: openair_admin@eurecom.fr
  OpenAirInterface Tech : openair_tech@eurecom.fr
  OpenAirInterface Dev  : openair4g-devel@lists.eurecom.fr

  Address      : Eurecom, Compus SophiaTech 450, route des chappes, 06451 Biot, France.

 *******************************************************************************/
/*****************************************************************************
 Source     UEprocess.c

 Version        0.1

 Date       2012/02/27

 Product        NAS stack

 Subsystem  UE NAS main process

 Author     Frederic Maurel

 Description    Implements the Non-Access Stratum protocol for Evolved Packet
 system (EPS) running at the User Equipment side.

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

#include "commonDef.h"
#include "nas_log.h"
#include "nas_timer.h"

#include "user_api.h"
#include "network_api.h"
#include "nas_user.h"
#include "nas_network.h"
#include "nas_parser.h"

#include <stdlib.h> // exit
#include <poll.h>   // poll
#include <string.h> // memset
#include <signal.h> // sigaction
#include <pthread.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  *******************/
/****************************************************************************/

#define NAS_SLEEP_TIMEOUT 1000  /* 1 second */

static void *_nas_user_mngr(void *);
static void *_nas_network_mngr(void *);

static int _nas_set_signal_handler(int signal, void (handler)(int));
static void _nas_signal_handler(int signal);

static void _nas_clean(int usr_fd, int net_fd);

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

/****************************************************************************/
int main(int argc, const char *argv[])
{
  /*
   * Get the command line options
   */
  if (nas_parser_get_options (argc, argv) != RETURNok) {
    nas_parser_print_usage (FIRMWARE_VERSION);
    exit (EXIT_FAILURE);
  }

  /*
   * Initialize logging trace utility
   */
  nas_log_init (nas_parser_get_trace_level ());

  const char *uhost = nas_parser_get_user_host ();
  const char *uport = nas_parser_get_user_port ();
  const char *devpath = nas_parser_get_device_path ();
  const char *devparams = nas_parser_get_device_params ();
  const char *nhost = nas_parser_get_network_host ();
  const char *nport = nas_parser_get_network_port ();

  LOG_TRACE (INFO,
             "UE-MAIN   - %s -ueid %d -uhost %s -uport %s -nhost %s -nport %s -dev %s -params %s -trace 0x%x",
             argv[0], nas_parser_get_ueid (), uhost, uport, nhost, nport, devpath, devparams,
             nas_parser_get_trace_level ());

  /*
   * Initialize the User interface
   */
  if (user_api_initialize (uhost, uport, devpath, devparams) != RETURNok) {
    LOG_TRACE (ERROR, "UE-MAIN   - user_api_initialize() failed");
    exit (EXIT_FAILURE);
  }

  int user_fd = user_api_get_fd ();

  /*
   * Initialize the Network interface
   */
  if (network_api_initialize (nhost, nport) != RETURNok) {
    LOG_TRACE (ERROR, "UE-MAIN   - network_api_initialize() failed");
    user_api_close (user_fd);
    exit (EXIT_FAILURE);
  }

  int network_fd = network_api_get_fd ();

  /*
   * Initialize the NAS contexts
   */
  nas_user_initialize (&user_api_emm_callback, &user_api_esm_callback,
                       FIRMWARE_VERSION);
  nas_network_initialize ();

  /*
   * Initialize NAS timer handlers
   */
  nas_timer_init ();

  /*
   * Set up signal handlers
   */
  (void) _nas_set_signal_handler (SIGINT, _nas_signal_handler);
  (void) _nas_set_signal_handler (SIGTERM, _nas_signal_handler);

  pthread_attr_t attr;
  pthread_attr_init (&attr);
  pthread_attr_setscope (&attr, PTHREAD_SCOPE_SYSTEM);
  pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);

  /*
   * Start thread use to manage the user connection endpoint
   */
  pthread_t user_mngr;

  if (pthread_create (&user_mngr, &attr, _nas_user_mngr, &user_fd) != 0) {
    LOG_TRACE (ERROR, "UE-MAIN   - "
               "Failed to create the user management thread");
    user_api_close (user_fd);
    network_api_close (network_fd);
    exit (EXIT_FAILURE);
  }

  /*
   * Start thread use to manage the network connection endpoint
   */
  pthread_t network_mngr;

  if (pthread_create (&network_mngr, &attr, _nas_network_mngr,
                      &network_fd) != 0) {
    LOG_TRACE (ERROR, "UE-MAIN   - "
               "Failed to create the network management thread");
    user_api_close (user_fd);
    network_api_close (network_fd);
    exit (EXIT_FAILURE);
  }

  pthread_attr_destroy (&attr);

  /*
   * Suspend execution of the main process until all connection
   * endpoints are still active
   */
  while ((user_fd != -1) && (network_fd != -1)) {
    poll (NULL, 0, NAS_SLEEP_TIMEOUT);
    user_fd = user_api_get_fd ();
    network_fd = network_api_get_fd ();
  }

  /* Termination cleanup */
  _nas_clean (user_fd, network_fd);

  LOG_TRACE
  (WARNING, "UE-MAIN   - NAS main process exited");
}

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

/****************************************************************************
 **                                                                        **
 ** Name:    _nas_user_mngr()                                          **
 **                                                                        **
 ** Description: Manages the connection endpoint use to communicate with   **
 **      the user application layer                                **
 **                                                                        **
 ** Inputs:  fd:        The descriptor of the user connection end- **
 **             point                                      **
 **          Others:    None                                       **
 **                                                                        **
 ** Outputs:     Return:    None                                       **
 **          Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static void *_nas_user_mngr(void *args)
{
  LOG_FUNC_IN;

  int exit_loop = FALSE;

  int *fd = (int *) args;

  LOG_TRACE (INFO, "UE-MAIN   - User connection manager started (%d)", *fd);

  /* User receiving loop */
  while (!exit_loop) {
    exit_loop = nas_user_receive_and_process(fd, NULL);
  }

  /* Close the connection to the user application layer */
  user_api_close (*fd);
  LOG_TRACE (WARNING, "UE-MAIN   - "
             "The user connection endpoint manager exited");

  LOG_FUNC_RETURN(NULL);
}

/****************************************************************************
 **                                                                        **
 ** Name:    _nas_network_mngr()                                       **
 **                                                                        **
 ** Description: Manages the connection endpoint use to communicate with   **
 **      the network sublayer                                      **
 **                                                                        **
 ** Inputs:  fd:        The descriptor of the network connection   **
 **             endpoint                                   **
 **          Others:    None                                       **
 **                                                                        **
 ** Outputs:     Return:    None                                       **
 **          Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static void *_nas_network_mngr(void *args)
{
  LOG_FUNC_IN;

  int ret_code;
  int network_message_id;
  int bytes;

  int *fd = (int *) args;

  LOG_TRACE (INFO, "UE-MAIN   - Network connection manager started (%d)", *fd);

  /* Network receiving loop */
  while (TRUE) {
    /* Read the network data message */
    bytes = network_api_read_data (*fd);

    if (bytes == RETURNerror) {
      /* Failed to read data from the network sublayer;
       * exit from the receiving loop */
      LOG_TRACE (ERROR, "UE-MAIN   - "
                 "Failed to read data from the network sublayer");
      break;
    }

    if (bytes == 0) {
      /* A signal was caught before any data were available */
      continue;
    }

    /* Decode the network data message */
    network_message_id = network_api_decode_data (bytes);

    if (network_message_id == RETURNerror) {
      /* Failed to decode data read from the network sublayer */
      continue;
    }

    /* Process the network data message */
    ret_code = nas_network_process_data (network_message_id,
                                         network_api_get_data ());

    if (ret_code != RETURNok) {
      /* The network data message has not been successfully
       * processed */
      LOG_TRACE
      (WARNING, "UE-MAIN   - "
       "The network procedure call 0x%x failed",
       network_message_id);
    }
  }

  /* Close the connection to the network sublayer */
  network_api_close (*fd);
  LOG_TRACE (WARNING, "UE-MAIN   - "
             "The network connection endpoint manager exited");

  LOG_FUNC_RETURN(NULL);
}

/****************************************************************************
 **                                                                        **
 ** Name:    _nas_set_signal_handler()                                 **
 **                                                                        **
 ** Description: Set up a signal handler                                   **
 **                                                                        **
 ** Inputs:  signal:    Signal number                              **
 **          handler:   Signal handler                             **
 **          Others:    None                                       **
 **                                                                        **
 ** Outputs:     Return:    RETURNerror, RETURNok                      **
 **          Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static int _nas_set_signal_handler(int signal, void (handler)(int))
{
  LOG_FUNC_IN;

  struct sigaction act;

  /* Initialize signal set */
  (void) memset (&act, 0, sizeof(act));
  (void) sigfillset (&act.sa_mask);
  (void) sigdelset (&act.sa_mask, SIGHUP);
  (void) sigdelset (&act.sa_mask, SIGINT);
  (void) sigdelset (&act.sa_mask, SIGTERM);
  (void) sigdelset (&act.sa_mask, SIGILL);
  (void) sigdelset (&act.sa_mask, SIGTRAP);
  (void) sigdelset (&act.sa_mask, SIGIOT);
#ifndef LINUX
  (void) sigdelset (&act.sa_mask, SIGEMT);
#endif
  (void) sigdelset (&act.sa_mask, SIGFPE);
  (void) sigdelset (&act.sa_mask, SIGBUS);
  (void) sigdelset (&act.sa_mask, SIGSEGV);
  (void) sigdelset (&act.sa_mask, SIGSYS);

  /* Initialize signal handler */
  act.sa_handler = handler;

  if (sigaction (signal, &act, 0) < 0) {
    return RETURNerror;
  }

  LOG_TRACE (INFO, "UE-MAIN   - Handler successfully set for signal %d", signal);

  LOG_FUNC_RETURN(RETURNok);
}

/****************************************************************************
 **                                                                        **
 ** Name:    _nas_signal_handler()                                     **
 **                                                                        **
 ** Description: Signal handler                                            **
 **                                                                        **
 ** Inputs:  signal:    Signal number                              **
 **          Others:    None                                       **
 **                                                                        **
 ** Outputs:     Return:    None                                       **
 **          Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static void _nas_signal_handler(int signal)
{
  LOG_FUNC_IN;

  LOG_TRACE (WARNING, "UE-MAIN   - Signal %d received", signal);
  _nas_clean (user_api_get_fd (), network_api_get_fd ());
  exit (EXIT_SUCCESS);

  LOG_FUNC_OUT
  ;
}

/****************************************************************************
 **                                                                        **
 ** Name:    _nas_clean()                                              **
 **                                                                        **
 ** Description: Performs termination cleanup                              **
 **                                                                        **
 ** Inputs:  usr_fd:    User's connection file descriptor          **
 **      net_fd:    Network's connection file descriptor       **
 **          Others:    None                                       **
 **                                                                        **
 ** Outputs:     Return:    None                                       **
 **          Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static void _nas_clean(int usr_fd, int net_fd)
{
  LOG_FUNC_IN;

  LOG_TRACE (INFO, "UE-MAIN   - Perform EMM and ESM cleanup");
  nas_network_cleanup ();

  LOG_TRACE (INFO, "UE-MAIN   - "
             "Closing user connection %d and network connection %d",
             usr_fd, net_fd);
  user_api_close (usr_fd);
  network_api_close (net_fd);

  LOG_FUNC_OUT
  ;
}

