/*

 * glbp.c

 *

 * Gateway Load Balancing Protocol

 * 

 * Copyright (C) 2025 - ntop.org

 * Copyright (C) 2025 - V.G <v.gavrilov@securitycode.ru>

 *

 * 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_GLBP

#include "ndpi_api.h"

#include "ndpi_private.h"

#define GLBP_PORT 3222 /* IANA registered */

static void ndpi_int_glbp_add_connection(struct ndpi_detection_module_struct * const ndpi_struct,

                                         struct ndpi_flow_struct * const flow)

{

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

  ndpi_set_detected_protocol(ndpi_struct, flow,

                             NDPI_PROTOCOL_GLBP, NDPI_PROTOCOL_UNKNOWN,

                             NDPI_CONFIDENCE_DPI);

}

static void ndpi_search_glbp(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 GLBP\n");

  if (packet->payload_packet_len < 12) {

    goto exclude;

  }

  if ((packet->udp->source != htons(GLBP_PORT)) || 

      (packet->udp->dest != htons(GLBP_PORT)))

  {

    goto exclude;

  }

  if ((packet->payload[0] > 1) ||

      (ntohs(get_u_int16_t(packet->payload, 2)) > 1023))

  {

    goto exclude;

  }

  ndpi_int_glbp_add_connection(ndpi_struct, flow);

  return;

exclude:

  NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

}

void init_glbp_dissector(struct ndpi_detection_module_struct *ndpi_struct)

{

  register_dissector("GLBP", ndpi_struct,

                     ndpi_search_glbp,

                     NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,

                     1, NDPI_PROTOCOL_GLBP);

}