/*
 * rtsp.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_RTSP

#include "ndpi_api.h"

static void ndpi_int_rtsp_add_connection(struct ndpi_detection_module_struct *ndpi_struct,
        struct ndpi_flow_struct *flow/* , */
        /* ndpi_protocol_type_t protocol_type */)
{
    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_RTSP);
}

/* this function searches for a rtsp-"handshake" over tcp or udp. */
void ndpi_search_rtsp_tcp_udp(struct ndpi_detection_module_struct
        *ndpi_struct, struct ndpi_flow_struct *flow)
{
    struct ndpi_packet_struct *packet = &flow->packet;

    struct ndpi_id_struct *src = flow->src;
    struct ndpi_id_struct *dst = flow->dst;

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

    if (flow->rtsprdt_stage == 0
            && !(packet->detected_protocol == NDPI_PROTOCOL_RTCP)
       ) {
        flow->rtsprdt_stage = 1 + packet->packet_direction;
        NDPI_LOG_DBG2(ndpi_struct, "maybe handshake 1; need next packet, return\n");
        return;
    }

    if (flow->packet_counter < 3 && flow->rtsprdt_stage == 1 + packet->packet_direction) {

        NDPI_LOG_DBG2(ndpi_struct, "maybe handshake 2; need next packet\n");
        return;
    }

    if (packet->payload_packet_len > 20 && flow->rtsprdt_stage == 2 - packet->packet_direction) {
        char buf[32] = { 0 };
        u_int len = packet->payload_packet_len;

        if(len >= (sizeof(buf)-1)) len = sizeof(buf)-1;
        strncpy(buf, (const char*)packet->payload, len);

        // RTSP Server Message
        if((memcmp(packet->payload, "RTSP/1.0 ", 9) == 0)
                || (strstr(buf, "rtsp://") != NULL)) {
            NDPI_LOG_DBG2(ndpi_struct, "found RTSP/1.0 \n");
            if (dst != NULL) {
                NDPI_LOG_DBG2(ndpi_struct, "found dst\n");
                ndpi_packet_src_ip_get(packet, &dst->rtsp_ip_address);
                dst->rtsp_timer = packet->tick_timestamp;
                dst->rtsp_ts_set = 1;
            }
            if (src != NULL) {
                NDPI_LOG_DBG2(ndpi_struct, "found src\n");
                ndpi_packet_dst_ip_get(packet, &src->rtsp_ip_address);
                src->rtsp_timer = packet->tick_timestamp;
                src->rtsp_ts_set = 1;
            }
            NDPI_LOG_INFO(ndpi_struct, "found RTSP\n");
            flow->rtsp_control_flow = 1;
            ndpi_int_rtsp_add_connection(ndpi_struct, flow);
            return;
        }
    }
    if (packet->udp != NULL && packet->detected_protocol == NDPI_PROTOCOL_UNKNOWN
            && ((NDPI_COMPARE_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_RTP) == 0)
                || (NDPI_COMPARE_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_RTCP) == 0)
               )) {
        NDPI_LOG_DBG2(ndpi_struct,
                "maybe RTSP RTP, RTSP RTCP, RDT; need next packet.\n");
        return;
    }


    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
    return;
}


void init_rtsp_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("RTSP", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_RTSP,
            ndpi_search_rtsp_tcp_udp,
            NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP_WITH_PAYLOAD,
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);
    *id += 1;
}
