/*
 * checkmk.c
 *
 * Copyright (C) 2011-18 - ntop.org
 *
 * 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_CHECKMK

#include "ndpi_api.h"


static void ndpi_int_checkmk_add_connection(struct ndpi_detection_module_struct *ndpi_struct,
        struct ndpi_flow_struct *flow)
{
    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_CHECKMK);
}

void ndpi_search_checkmk(struct ndpi_detection_module_struct *ndpi_struct,
        struct ndpi_flow_struct *flow)
{
    struct ndpi_packet_struct *packet = &flow->packet;

    if (packet->payload_packet_len >= 15) {

        if(packet->payload_packet_len > 128) {
            /*
               When we transfer a large data chunk, unless we have observed
               the initial connection, we need to discard these packets
               as they are not an indication that this flow is not AFP
               */
            return;
        }

        /*
         * this will detect the OpenSession command of the Data Stream Interface (DSI) protocol
         * which is exclusively used by the Apple Filing Protocol (AFP) on TCP/IP networks
         */
        if (packet->payload_packet_len >= 15 && packet->payload_packet_len < 100
                && memcmp(packet->payload, "<<<check_mk>>>", 14) == 0) {

            NDPI_LOG(NDPI_PROTOCOL_CHECKMK, ndpi_struct, NDPI_LOG_DEBUG, "Check_MK: Flow detected.\n");
            ndpi_int_checkmk_add_connection(ndpi_struct, flow);
            return;
        }
    }

    NDPI_LOG(NDPI_PROTOCOL_CHECKMK, ndpi_struct, NDPI_LOG_DEBUG, "Check_MK excluded.\n");
    NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_CHECKMK);
}


void init_checkmk_dissector(struct ndpi_detection_module_struct *ndpi_struct,
        u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("CHECKMK", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_CHECKMK,
            ndpi_search_checkmk,
            NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);
    *id += 1;
}
