/*
 * telegram.c
 *
 * Copyright (C) 2014 by Gianluca Costa xplico.org
 * Copyright (C) 2012-18 - 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_TELEGRAM

#include "ndpi_api.h"

static void ndpi_int_telegram_add_connection(struct ndpi_detection_module_struct
                                             *ndpi_struct, struct ndpi_flow_struct *flow)
{
  ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_TELEGRAM, NDPI_PROTOCOL_UNKNOWN);
  NDPI_LOG_INFO(ndpi_struct, "found telegram\n");
}


void ndpi_search_telegram(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
  struct ndpi_packet_struct *packet = &flow->packet;
  u_int16_t dport /* , sport */;
  
  NDPI_LOG_DBG(ndpi_struct, "search telegram\n");

  if (packet->payload_packet_len == 0)
    return;
  if (packet->tcp != NULL) {
    if (packet->payload_packet_len > 56) {
      dport = ntohs(packet->tcp->dest);
      /* sport = ntohs(packet->tcp->source); */

      if (packet->payload[0] == 0xef && (
          dport == 443 || dport == 80 || dport == 25
        )) {
        if (packet->payload[1] == 0x7f) {
          ndpi_int_telegram_add_connection(ndpi_struct, flow);
        }
        else if (packet->payload[1]*4 <= packet->payload_packet_len - 1) {
          ndpi_int_telegram_add_connection(ndpi_struct, flow);
        }
        return;
      }
    }
  }

  NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}


void init_telegram_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
  ndpi_set_bitmask_protocol_detection("Telegram", ndpi_struct, detection_bitmask, *id,
				      NDPI_PROTOCOL_TELEGRAM,
				      ndpi_search_telegram,
				      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP,
				      SAVE_DETECTION_BITMASK_AS_UNKNOWN,
				      ADD_TO_DETECTION_BITMASK);

  *id += 1;
}

