/*

 * halflife2_and_mods.c

 *

 * Copyright (C) 2009-11 - ipoque GmbH

 * Copyright (C) 2011-22 - 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_HALFLIFE2

#include "ndpi_api.h"

static void ndpi_int_halflife2_add_connection(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)

{

  ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_HALFLIFE2, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);

}

static void ndpi_search_halflife2(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)

{

  struct ndpi_packet_struct *packet = &ndpi_struct->packet;

  NDPI_LOG_DBG(ndpi_struct, "search halflife2\n");

  if (flow->l4.udp.halflife2_stage == 0) {

    if (packet->payload_packet_len >= 20

      && get_u_int32_t(packet->payload, 0) == 0xFFFFFFFF

      && get_u_int32_t(packet->payload, packet->payload_packet_len - 4) == htonl(0x30303000)) {

      flow->l4.udp.halflife2_stage = 1 + packet->packet_direction;

      NDPI_LOG_DBG2(ndpi_struct,

          "halflife2 client req detected, waiting for server reply\n");

      return;

    }

  } else if (flow->l4.udp.halflife2_stage == 2 - packet->packet_direction) {

    if (packet->payload_packet_len >= 20

      && get_u_int32_t(packet->payload, 0) == 0xFFFFFFFF

      && get_u_int32_t(packet->payload, packet->payload_packet_len - 4) == htonl(0x30303000)) {

      ndpi_int_halflife2_add_connection(ndpi_struct, flow);

      NDPI_LOG_INFO(ndpi_struct, "found halflife2\n");

      return;

    }

  }

  NDPI_EXCLUDE_PROTO(ndpi_struct, flow);

}

void init_halflife2_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id)

{

  ndpi_set_bitmask_protocol_detection("HalfLife2", ndpi_struct, *id,

              NDPI_PROTOCOL_HALFLIFE2,

              ndpi_search_halflife2,

              NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,

              SAVE_DETECTION_BITMASK_AS_UNKNOWN,

              ADD_TO_DETECTION_BITMASK);

  *id += 1;

}