/*

 * ultrasurf.c

 *

 * Copyright (C) 2022-23 - ntop.org

 *

 * 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_ULTRASURF

#include "ndpi_api.h"

#include "ndpi_private.h"

static void ndpi_int_ultrasurf_add_connection(struct ndpi_detection_module_struct * const ndpi_struct,

                                              struct ndpi_flow_struct * const flow)

{

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

  ndpi_set_detected_protocol(ndpi_struct, flow,

                             NDPI_PROTOCOL_ULTRASURF,

                             NDPI_PROTOCOL_UNKNOWN,

                             NDPI_CONFIDENCE_DPI);

}

static void ndpi_search_ultrasurf(struct ndpi_detection_module_struct *ndpi_struct,

                                  struct ndpi_flow_struct *flow)

{

  struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;

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

  if (packet->payload_packet_len < 8)

  {

    NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

    return;

  }

  if (htonl(get_u_int32_t(packet->payload, 0)) == 0xcc1c3041 &&

      htonl(get_u_int32_t(packet->payload, 4)) == 0x5ba43866)

  {

    ndpi_int_ultrasurf_add_connection(ndpi_struct, flow);

  }

  NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

}

void init_ultrasurf_dissector(struct ndpi_detection_module_struct *ndpi_struct)

{

  register_dissector("UltraSurf", ndpi_struct,

                     ndpi_search_ultrasurf,

                     NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,

                     1, NDPI_PROTOCOL_ULTRASURF);

}