/*
 * ayiya.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/>.
 *
 */

/*
http://en.wikipedia.org/wiki/Anything_In_Anything
http://tools.ietf.org/html/rfc4891
*/

#include "ndpi_protocol_ids.h"

#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_AYIYA

#include "ndpi_api.h"

struct ayiya {
    u_int8_t flags[3];
    u_int8_t next_header;
    u_int32_t epoch;
    u_int8_t identity[16];
    u_int8_t signature[20];
};

void ndpi_search_ayiya(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 AYIYA\n");

    if(packet->udp && (packet->detected_protocol == NDPI_PROTOCOL_UNKNOWN)) {
        /* Ayiya is udp based, port 5072 */
        if ((packet->udp->source == htons(5072) || packet->udp->dest == htons(5072))
                /* check for ayiya new packet */
                && (packet->payload_packet_len > 44)
           ) {
            /* FINISH */
            struct ayiya *a = (struct ayiya*)packet->payload;
            u_int32_t epoch = ntohl(a->epoch), now;
            u_int32_t fiveyears = 86400 * 365 * 5;

            now = flow->packet.tick_timestamp;

            if((epoch >= (now - fiveyears)) && (epoch <= (now+86400 /* 1 day */))) {
                NDPI_LOG_INFO(ndpi_struct, "found AYIYA\n");
                ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_AYIYA);
            }

            return;
        }

        NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
    }
}


void init_ayiya_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("Ayiya", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_AYIYA,
            ndpi_search_ayiya,
            NDPI_SELECTION_BITMASK_PROTOCOL_UDP_WITH_PAYLOAD,
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);

    *id += 1;
}
