/*
 * tftp.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_TFTP

#include "ndpi_api.h"

static void ndpi_int_tftp_add_connection(struct ndpi_detection_module_struct
        *ndpi_struct, struct ndpi_flow_struct *flow)
{
    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_TFTP);
}

void ndpi_search_tftp(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 TFTP\n");

    if (packet->payload_packet_len > 3 && flow->l4.udp.tftp_stage == 0
            && ntohl(get_u_int32_t(packet->payload, 0)) == 0x00030001) {
        NDPI_LOG_DBG2(ndpi_struct, "maybe tftp. need next packet\n");
        flow->l4.udp.tftp_stage = 1;
        return;
    }
    if (packet->payload_packet_len > 3 && (flow->l4.udp.tftp_stage == 1)
            && ntohl(get_u_int32_t(packet->payload, 0)) == 0x00040001) {

        NDPI_LOG_INFO(ndpi_struct, "found tftp\n");
        ndpi_int_tftp_add_connection(ndpi_struct, flow);
        return;
    }
    if (packet->payload_packet_len > 1
            && ((packet->payload[0] == 0 && packet->payload[packet->payload_packet_len - 1] == 0)
                || (packet->payload_packet_len == 4 && ntohl(get_u_int32_t(packet->payload, 0)) == 0x00040000))) {
        NDPI_LOG_DBG2(ndpi_struct, "skip initial packet\n");
        return;
    }

    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}


void init_tftp_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("TFTP", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_TFTP,
            ndpi_search_tftp,
            NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);

    *id += 1;
}

