/*
 * edonkey.c
 *
 * Copyright (C) 2024 - ntop.org and contributors
 *
 * 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_EDONKEY

#include "ndpi_api.h"
#include "ndpi_private.h"

static void ndpi_int_edonkey_add_connection(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) {
  NDPI_LOG_INFO(ndpi_struct, "found EDONKEY\n");
  ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_EDONKEY, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
}

static void ndpi_search_edonkey(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) {
  struct ndpi_packet_struct *packet = &ndpi_struct->packet;
  u_int8_t protocol;
  u_int32_t message_length;

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

  if(packet->payload_packet_len > 5) {
    protocol = packet->payload[0];
    /* 0xE3: Edonkey, 0xC5: eMule extensions, 0xD4: eMule compressed */
    if(protocol != 0xE3 && protocol != 0xC5 && protocol != 0xD4) {
      NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
      return;
    }
    message_length = packet->payload_packet_len - 5;
    if(message_length == le32toh(get_u_int32_t(packet->payload, 1))) {
      ndpi_int_edonkey_add_connection(ndpi_struct, flow);
      return;
    }
  }

  NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}


void init_edonkey_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id)
{
  ndpi_set_bitmask_protocol_detection("eDonkey", ndpi_struct, *id,
				      NDPI_PROTOCOL_EDONKEY,
				      ndpi_search_edonkey,
				      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
				      SAVE_DETECTION_BITMASK_AS_UNKNOWN,
				      ADD_TO_DETECTION_BITMASK);

  *id += 1;
}