/*
 * iec60870-5-104.c
 * Extension for industrial 104 protocol recognition
 *
 * Created by Cesar HM <cesar91hoyos@gmail.com>
 *
 * Copyright (C) 2019 - ntop.org
 *
 * This file is part of nDPI, an open source deep packet inspection
 * library based on the OpenDPI and PACE technology by ipoque GmbH
 *
 * nDPI is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * nDPI 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with nDPI.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "ndpi_protocol_ids.h"
#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_IEC60870
#include "ndpi_api.h"

void ndpi_search_iec60870_tcp(struct ndpi_detection_module_struct *ndpi_struct,
                            struct ndpi_flow_struct *flow) {
  struct ndpi_packet_struct *packet = &flow->packet;
  u_int16_t iec104_port = htons(2404); // port used by IEC60870

  /* Check connection over TCP */
  NDPI_LOG_DBG(ndpi_struct, "search IEC60870\n");
  
  if(packet->tcp) {
    /* The start byte of 104 is 0x68
     * The usual port: 2404
     */
    if((packet->payload[0] == 0x68) && 
       ((packet->tcp->dest == iec104_port) || (packet->tcp->source == iec104_port)) ){
      NDPI_LOG_INFO(ndpi_struct, "found 104\n");
      ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_IEC60870, NDPI_PROTOCOL_UNKNOWN);
      return;
    }
  }
  
  NDPI_EXCLUDE_PROTO(ndpi_struct, flow);   
}



void init_104_dissector(struct ndpi_detection_module_struct *ndpi_struct,
                           u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask) {	
  ndpi_set_bitmask_protocol_detection("IEC60870", ndpi_struct, detection_bitmask, *id,
				      NDPI_PROTOCOL_IEC60870,
				      ndpi_search_iec60870_tcp,
				      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
				      SAVE_DETECTION_BITMASK_AS_UNKNOWN,
				      ADD_TO_DETECTION_BITMASK);
  *id += 1;
}