/*
 * fasttrack.c
 *
 * Copyright (C) 2009-2011 by ipoque GmbH
 * 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_FASTTRACK

#include "ndpi_api.h"


static void ndpi_int_fasttrack_add_connection(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_FASTTRACK);
}

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

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

    if ( (packet->payload != NULL)
            && (packet->payload_packet_len > 6)
            && (ntohs(get_u_int16_t(packet->payload, packet->payload_packet_len - 2)) == 0x0d0a)) {
        NDPI_LOG_DBG2(ndpi_struct, "detected 0d0a at the end of the packet\n");

        if (memcmp(packet->payload, "GIVE ", 5) == 0 && packet->payload_packet_len >= 8) {
            u_int16_t i;
            for (i = 5; i < (packet->payload_packet_len - 2); i++) {
                // make shure that the argument to GIVE is numeric
                if (!(packet->payload[i] >= '0' && packet->payload[i] <= '9')) {
                    goto exclude_fasttrack;
                }
            }

            NDPI_LOG_INFO(ndpi_struct, "found FASTTRACK\n");
            ndpi_int_fasttrack_add_connection(ndpi_struct, flow);
            return;
        }

        if (packet->payload_packet_len > 50 && memcmp(packet->payload, "GET /", 5) == 0) {
            u_int8_t a = 0;
            NDPI_LOG_DBG2(ndpi_struct, "detected GET /. \n");
            ndpi_parse_packet_line_info(ndpi_struct, flow);
            for (a = 0; a < packet->parsed_lines; a++) {
                if ((packet->line[a].len > 17 && memcmp(packet->line[a].ptr, "X-Kazaa-Username: ", 18) == 0)
                        || (packet->line[a].len > 23 && memcmp(packet->line[a].ptr, "User-Agent: PeerEnabler/", 24) == 0)) {
                    NDPI_LOG_INFO(ndpi_struct,
                            "found FASTTRACK X-Kazaa-Username: || User-Agent: PeerEnabler/\n");
                    ndpi_int_fasttrack_add_connection(ndpi_struct, flow);
                    return;
                }
            }
        }
    }

exclude_fasttrack:
    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}


void init_fasttrack_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("FastTrack", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_FASTTRACK,
            ndpi_search_fasttrack_tcp,
            NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);

    *id += 1;
}
