/*
 * 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 netlink_init.c
* \brief initiate the netlink socket for communication with nas dirver
* \author Navid Nikaein and Raymomd Knopp
* \date 2011
* \version 1.0
* \company Eurecom
* \email: navid.nikaein@eurecom.fr
*/

#include <sys/socket.h>
#include <linux/netlink.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#include <errno.h>
#include "common/platform_constants.h"

#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include "common/openairinterface5g_limits.h"

#include "pdcp.h"

char nl_rx_buf[NL_MAX_PAYLOAD];

struct sockaddr_nl nas_src_addr, nas_dest_addr;

int nas_sock_fd[MAX_MOBILES_PER_ENB*2]; //Allocated for both LTE UE and NR UE.

int nas_sock_mbms_fd;

struct msghdr nas_msg_tx;
struct msghdr nas_msg_rx;

static int tun_alloc(char *dev) {
  struct ifreq ifr;
  int fd, err;

  if( (fd = open("/dev/net/tun", O_RDWR)) < 0 ) {
    LOG_E(PDCP, "[TUN] failed to open /dev/net/tun\n");
    return -1;
  }

  memset(&ifr, 0, sizeof(ifr));
  /* Flags: IFF_TUN   - TUN device (no Ethernet headers)
   *        IFF_TAP   - TAP device
   *
   *        IFF_NO_PI - Do not provide packet information
   */
  ifr.ifr_flags = IFF_TUN | IFF_NO_PI;

  if( *dev )
    strncpy(ifr.ifr_name, dev, sizeof(ifr.ifr_name)-1);

  if( (err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ) {
    close(fd);
    return err;
  }

  strcpy(dev, ifr.ifr_name);
  return fd;
}


int netlink_init_mbms_tun(char *ifprefix, int id) {//for UE, id = 1, 2, ...,
  int ret;
  char ifname[64];

    if (id > 0) {
      sprintf(ifname, "oaitun_%.3s%d", ifprefix, id-1);
    }
    else {
      sprintf(ifname, "oaitun_%.3s1", ifprefix); // added "1": for historical reasons
    }
    nas_sock_mbms_fd = tun_alloc(ifname);

    if (nas_sock_mbms_fd == -1) {
      printf("[NETLINK] Error opening mbms socket %s (%d:%s)\n",ifname,errno, strerror(errno));
      exit(1);
    }

    printf("[NETLINK]Opened socket %s with fd %d\n",ifname,nas_sock_mbms_fd);
    ret = fcntl(nas_sock_mbms_fd,F_SETFL,O_NONBLOCK);

    if (ret == -1) {
      printf("[NETLINK] Error fcntl (%d:%s)\n",errno, strerror(errno));

      if (LINK_ENB_PDCP_TO_IP_DRIVER) {
        exit(1);
      }
    }

    memset(&nas_src_addr, 0, sizeof(nas_src_addr));
    nas_src_addr.nl_family = AF_NETLINK;
    nas_src_addr.nl_pid = 1;//getpid();  /* self pid */
    nas_src_addr.nl_groups = 0;  /* not in mcast groups */
    ret = bind(nas_sock_mbms_fd, (struct sockaddr *)&nas_src_addr, sizeof(nas_src_addr));

  return 1;
}

int netlink_init_tun(char *ifprefix, int num_if, int id) {//for UE, id = 1, 2, ...,
  int ret;
  char ifname[64];

  int begx = (id == 0) ? 0 : id - 1;
  int endx = (id == 0) ? num_if : id;
  for (int i = begx; i < endx; i++) {
    sprintf(ifname, "oaitun_%.3s%d",ifprefix,i+1);
    nas_sock_fd[i] = tun_alloc(ifname);

    if (nas_sock_fd[i] == -1) {
      LOG_E(PDCP, "TUN: Error opening socket %s (%d:%s)\n",ifname,errno, strerror(errno));
      return 0;
    }

    LOG_I(PDCP, "TUN: Opened socket %s with fd nas_sock_fd[%d]=%d\n",
           ifname, i, nas_sock_fd[i]);
    ret = fcntl(nas_sock_fd[i],F_SETFL,O_NONBLOCK);

    if (ret == -1) {
      LOG_E(PDCP, "TUN: Error fcntl (%d:%s)\n",errno, strerror(errno));

      if (LINK_ENB_PDCP_TO_IP_DRIVER) {
        exit(1);
      }
    }
  } /* for */

  return 1;
}