/*
 * redis.c
 *
 * Copyright (C) 2011-18 - ntop.org
 *
 * 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_REDIS

#include "ndpi_api.h"

static void ndpi_int_redis_add_connection(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) {
    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_REDIS);
}

static void ndpi_check_redis(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) {
    struct ndpi_packet_struct *packet = &flow->packet;
    u_int32_t payload_len = packet->payload_packet_len;

    if(payload_len == 0) return; /* Shouldn't happen */

    /* Break after 20 packets. */
    if(flow->packet_counter > 20) {
        NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
        return;
    }

    if(packet->packet_direction == 0)
        flow->redis_s2d_first_char = packet->payload[0];
    else
        flow->redis_d2s_first_char = packet->payload[0];

    if((flow->redis_s2d_first_char != '\0') && (flow->redis_d2s_first_char != '\0')) {
        /*
         *1
         $4
         PING
         +PONG
         *3
         $3
         SET
         $19
         dns.cache.127.0.0.1
         $9
         localhost
         +OK
         */

        if(((flow->redis_s2d_first_char == '*')
                    && ((flow->redis_d2s_first_char == '+') || (flow->redis_d2s_first_char == ':')))
                || ((flow->redis_d2s_first_char == '*')
                    && ((flow->redis_s2d_first_char == '+') || (flow->redis_s2d_first_char == ':')))) {
            NDPI_LOG_INFO(ndpi_struct, "Found Redis\n");
            ndpi_int_redis_add_connection(ndpi_struct, flow);
        } else {
            NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
        }
    } else
        return; /* Too early */
}

void ndpi_search_redis(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 Redis\n");

    /* skip marked packets */
    if (packet->detected_protocol != NDPI_PROTOCOL_REDIS) {
        if (packet->tcp_retransmission == 0) {
            ndpi_check_redis(ndpi_struct, flow);
        }
    }
}


void init_redis_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
    ndpi_set_bitmask_protocol_detection("Redis", ndpi_struct, detection_bitmask, *id,
            NDPI_PROTOCOL_REDIS,
            ndpi_search_redis,
            NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
            SAVE_DETECTION_BITMASK_AS_UNKNOWN,
            ADD_TO_DETECTION_BITMASK);

    *id += 1;
}
