/*
 * shoutcast.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_SHOUTCAST

#include "ndpi_api.h"

static void ndpi_int_shoutcast_add_connection(struct ndpi_detection_module_struct
        *ndpi_struct, struct ndpi_flow_struct *flow)
{
    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_SHOUTCAST);
}

void ndpi_search_shoutcast_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 shoutcast\n");

    if (flow->packet_counter == 1) {
        /* this case in paul_upload_oddcast_002.pcap */
        if (packet->payload_packet_len >= 6
                && packet->payload_packet_len < 80 && memcmp(packet->payload, "123456", 6) == 0) {
            NDPI_LOG_DBG2(ndpi_struct, "Shoutcast stage 1, \"123456\"\n");
            return;
        }
        if (flow->packet_counter < 3
                && packet->detected_protocol == NDPI_PROTOCOL_HTTP
           ) {
            NDPI_LOG_DBG2(ndpi_struct,
                    "http detected, need next packet for shoutcast detection.\n");
            if (packet->payload_packet_len > 4
                    && get_u_int32_t(packet->payload, packet->payload_packet_len - 4) != htonl(0x0d0a0d0a)) {
                NDPI_LOG_DBG2(ndpi_struct, "segmented packet found\n");
                flow->l4.tcp.shoutcast_stage = 1 + packet->packet_direction;
            }
            return;
        }


        /*  else
            goto exclude_shoutcast; */

    }
    /* evtl. für asym detection noch User-Agent:Winamp dazunehmen. */
    if (packet->payload_packet_len > 11 && memcmp(packet->payload, "ICY 200 OK\x0d\x0a", 12) == 0) {
        NDPI_LOG_INFO(ndpi_struct, "found shoutcast by ICY 200 OK\n");
        ndpi_int_shoutcast_add_connection(ndpi_struct, flow);
        return;
    }
    if (flow->l4.tcp.shoutcast_stage == 1 + packet->packet_direction
            && flow->packet_direction_counter[packet->packet_direction] < 5) {
        return;
    }

    if (flow->packet_counter == 2) {
        if (packet->payload_packet_len == 2 && memcmp(packet->payload, "\x0d\x0a", 2) == 0) {
            NDPI_LOG_DBG2(ndpi_struct, "Shoutcast stage 1 continuation\n");
            return;
        } else if (packet->payload_packet_len > 3 && memcmp(&packet->payload[0], "OK2", 3) == 0) {
            NDPI_LOG_DBG2(ndpi_struct, "Shoutcast stage 2, OK2 found\n");
            return;
        } else
            goto exclude_shoutcast;
    } else if (flow->packet_counter == 3 || flow->packet_counter == 4) {
        if (packet->payload_packet_len > 3 && memcmp(&packet->payload[0], "OK2", 3) == 0) {
            NDPI_LOG_DBG2(ndpi_struct, "Shoutcast stage 2, OK2 found\n");
            return;
        } else if (packet->payload_packet_len > 4 && memcmp(&packet->payload[0], "icy-", 4) == 0) {
            NDPI_LOG_INFO(ndpi_struct, "found Shoutcast\n");
            ndpi_int_shoutcast_add_connection(ndpi_struct, flow);
            return;
        } else
            goto exclude_shoutcast;
    }

exclude_shoutcast:
    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}


void init_shoutcast_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("ShoutCast", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_SHOUTCAST,
            ndpi_search_shoutcast_tcp,
            NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);

    *id += 1;
}

