/*
 * dofus.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_DOFUS

#include "ndpi_api.h"

static void ndpi_dofus_add_connection(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
    NDPI_LOG_INFO(ndpi_struct, "found dofus\n");
    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_DOFUS);
}

void ndpi_search_dofus(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 dofus\n");

    /* Dofus v 1.x.x */
    if (packet->payload_packet_len == 13 && get_u_int16_t(packet->payload, 1) == ntohs(0x0508)
            && get_u_int16_t(packet->payload, 5) == ntohs(0x04a0)
            && get_u_int16_t(packet->payload, packet->payload_packet_len - 2) == ntohs(0x0194)) {
        ndpi_dofus_add_connection(ndpi_struct, flow);
        return;
    }
    if (flow->l4.tcp.dofus_stage == 0) {
        if (packet->payload_packet_len == 3 && memcmp(packet->payload, "HG", 2) == 0
                && packet->payload[packet->payload_packet_len - 1] == 0)
            goto maybe_dofus;

        if (packet->payload_packet_len == 12 && memcmp(packet->payload, "Af", 2) == 0
                && packet->payload[packet->payload_packet_len - 1] == 0)
            goto maybe_dofus;

        if (packet->payload_packet_len == 35 && memcmp(packet->payload, "HC", 2) == 0
                && packet->payload[packet->payload_packet_len - 1] == 0)
            goto maybe_dofus;

        if (packet->payload_packet_len > 2 && packet->payload[0] == 'A'
                && (packet->payload[1] == 'x' || packet->payload[1] == 'X')
                && packet->payload[packet->payload_packet_len - 1] == 0)
            goto maybe_dofus;

        if (packet->payload_packet_len > 2 && memcmp(packet->payload, "Ad", 2)
                && packet->payload[packet->payload_packet_len - 1] == 0)
            goto maybe_dofus;

    }
    if (flow->l4.tcp.dofus_stage == 1) {
        if (packet->payload_packet_len == 11 && memcmp(packet->payload, "AT", 2) == 0
                && packet->payload[10] == 0x00) {
            ndpi_dofus_add_connection(ndpi_struct, flow);
            return;
        }
        if (packet->payload_packet_len == 5
                && packet->payload[0] == 'A' && packet->payload[4] == 0x00
                && (packet->payload[1] == 'T' || packet->payload[1] == 'k')) {
            ndpi_dofus_add_connection(ndpi_struct, flow);
            return;
        }
    }
    /* end Dofus 1.x.x */


    /* Dofus 2.0 */
    if ((packet->payload_packet_len == 11 || packet->payload_packet_len == 13 || packet->payload_packet_len == 49)
            && get_u_int32_t(packet->payload, 0) == ntohl(0x00050800)
            && get_u_int16_t(packet->payload, 4) == ntohs(0x0005)
            && get_u_int16_t(packet->payload, 8) == ntohs(0x0005)
            && packet->payload[10] == 0x18) {
        if (packet->payload_packet_len == 13
                && get_u_int16_t(packet->payload, packet->payload_packet_len - 2) != ntohs(0x0194)) {
            goto exclude;
        }
        if (packet->payload_packet_len == 49 && ntohs(get_u_int16_t(packet->payload, 15)) + 17 != packet->payload_packet_len) {
            goto exclude;
        }
        ndpi_dofus_add_connection(ndpi_struct, flow);
        return;
    }
    if (packet->payload_packet_len >= 41 && get_u_int16_t(packet->payload, 0) == ntohs(0x01b9) && packet->payload[2] == 0x26) {
        u_int16_t len, len2;
        len = ntohs(get_u_int16_t(packet->payload, 3));
        if ((len + 5 + 2) > packet->payload_packet_len)
            goto exclude;
        len2 = ntohs(get_u_int16_t(packet->payload, 5 + len));
        if (5 + len + 2 + len2 == packet->payload_packet_len) {
            ndpi_dofus_add_connection(ndpi_struct, flow);
            return;
        }
    }
    if (packet->payload_packet_len == 56
            && memcmp(packet->payload, "\x00\x11\x35\x02\x03\x00\x93\x96\x01\x00", 10) == 0) {
        u_int16_t len, len2;
        len = ntohs(get_u_int16_t(packet->payload, 10));
        if ((len + 12 + 2) > packet->payload_packet_len)
            goto exclude;
        len2 = ntohs(get_u_int16_t(packet->payload, 12 + len));
        if ((12 + len + 2 + len2 + 1) > packet->payload_packet_len)
            goto exclude;
        if (12 + len + 2 + len2 + 1 == packet->payload_packet_len && packet->payload[12 + len + 2 + len2] == 0x01) {
            ndpi_dofus_add_connection(ndpi_struct, flow);
            return;
        }
    }
exclude:
    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
    return;

maybe_dofus:
    flow->l4.tcp.dofus_stage = 1;
    NDPI_LOG_DBG2(ndpi_struct, "maybe dofus\n");
    return;

}

void init_dofus_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("Dofus", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_DOFUS,
            ndpi_search_dofus,
            NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);

    *id += 1;
}

