/*

 * eaq.c

 *

 * Copyright (C) 2015-22 - ntop.org

 *

 * This module 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.

 *

 * This module 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.

 * If not, see <http://www.gnu.org/licenses/>.

 *

 */

/*

  EAQ: Entitade Aferidora da Qualidade de Banda Larga

  http://www.brasilbandalarga.com.br

 */

#include "ndpi_protocol_ids.h"

#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_EAQ

#include "ndpi_api.h"

#include "ndpi_private.h"

#define EAQ_DEFAULT_PORT   6000

#define EAQ_DEFAULT_SIZE     16

static void ndpi_int_eaq_add_connection(struct ndpi_detection_module_struct *ndpi_struct,

          struct ndpi_flow_struct *flow) {

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

}

static void ndpi_search_eaq(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) {

  struct ndpi_packet_struct *packet = &ndpi_struct->packet;

  u_int16_t sport = ntohs(packet->udp->source), dport = ntohs(packet->udp->dest);

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

  do {

    if( (packet->payload_packet_len != EAQ_DEFAULT_SIZE) ||

        ((sport != EAQ_DEFAULT_PORT) && (dport != EAQ_DEFAULT_PORT)) )

      break;

      u_int32_t seq = (packet->payload[0] * 1000) + (packet->payload[1] * 100) + (packet->payload[2] * 10) + packet->payload[3];

      if(flow->l4.udp.eaq_pkt_id == 0)

        flow->l4.udp.eaq_sequence = seq;

      else {

        if( (flow->l4.udp.eaq_sequence != seq) &&

      ((flow->l4.udp.eaq_sequence+1) != seq))

    break;

  else

    flow->l4.udp.eaq_sequence = seq;

      }

      if(++flow->l4.udp.eaq_pkt_id == 4) {

        /* We have collected enough packets so we assume it's EAQ */

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

        ndpi_int_eaq_add_connection(ndpi_struct, flow);

        return;

      } else

  return;

  } while(0);

  NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

}

void init_eaq_dissector(struct ndpi_detection_module_struct *ndpi_struct)

{

  ndpi_register_dissector("EAQ", ndpi_struct,

                     ndpi_search_eaq,

                     NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,

                     1, NDPI_PROTOCOL_EAQ);

}