/*

 * ciscovpn.c

 *

 * Copyright (C) 2013-22 - 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/>.

 *

 * Dissector developed by Remy Mudingay <mudingay@ill.fr>

 *

 */

#include "ndpi_protocol_ids.h"

#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_CISCOVPN

#include "ndpi_api.h"

#include "ndpi_private.h"

/* ****************************************************************** */

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

{

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

}

/* ****************************************************************** */

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

{

  struct ndpi_packet_struct *packet = &ndpi_struct->packet;

  u_int16_t udport, usport;

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

  usport = ntohs(packet->udp->source), udport = ntohs(packet->udp->dest);

  if((usport == 10000 && udport == 10000)) {

    if((packet->payload_packet_len >= 4) &&

       (packet->payload[0] == 0xfe &&

  packet->payload[1] == 0x57 &&

  packet->payload[2] == 0x7e &&

  packet->payload[3] == 0x2b)

       ) {

      /* This is a good query  fe577e2b */

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

      ndpi_int_ciscovpn_add_connection(ndpi_struct, flow);

      return;

    }

    if(flow->num_processed_pkts > 5)

      NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);    

  } else

    NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);  

}

void init_ciscovpn_dissector(struct ndpi_detection_module_struct *ndpi_struct)

{

  register_dissector("CiscoVPN", ndpi_struct,

                     ndpi_search_ciscovpn,

                     NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,

                     1, NDPI_PROTOCOL_CISCOVPN);

}