/*

 * syslog.c

 *

 * Copyright (C) 2009-11 - ipoque GmbH

 * Copyright (C) 2011-26 - 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_SYSLOG

#include "ndpi_api.h"

#include "ndpi_private.h"

static void ndpi_int_syslog_add_connection(struct ndpi_detection_module_struct

             *ndpi_struct, struct ndpi_flow_struct *flow)

{

  ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_SYSLOG, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);

}

static void ndpi_search_syslog(struct ndpi_detection_module_struct *ndpi_struct,

             struct ndpi_flow_struct *flow)

{

  struct ndpi_packet_struct *packet = &ndpi_struct->packet;

  u_int16_t i;

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

  if (packet->payload_packet_len > 20 && packet->payload[0] == '<') {

    NDPI_LOG_DBG2(ndpi_struct, "checked len>20 and <1024 and first symbol=<\n");

    for (i = 1; i <= 3; i++) {

      if (packet->payload[i] < '0' || packet->payload[i] > '9') {

    break;

      }

    }

    NDPI_LOG_DBG2(ndpi_struct,

             "read symbols while the symbol is a number.\n");

    if (packet->payload[i++] != '>') {

      NDPI_LOG_DBG(ndpi_struct, "excluded, there is no > following the number\n");

      NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

      return;

    } else {

      NDPI_LOG_DBG2(ndpi_struct, "a > following the number\n");

    }

    if (packet->payload[i] == 0x20) {

      NDPI_LOG_DBG2(ndpi_struct, "a blank following the >: increment i\n");

      i++;

    } else {

      NDPI_LOG_DBG2(ndpi_struct, "no blank following the >: do nothing\n");

    }

    while (i < packet->payload_packet_len - 1)

    {

        if (ndpi_isalnum(packet->payload[i]) == 0)

        {

            if (packet->payload[i] == ' ' || packet->payload[i] == ':' ||

                packet->payload[i] == '=' || packet->payload[i] == '[' ||

                packet->payload[i] == '-')

            {

                break;

            }

            NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

            return;

        }

        i++;

    }

    if (packet->payload[i] == ':')

    {

        if (++i >= packet->payload_packet_len ||

            packet->payload[i] != ' ')

        {

            NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

            return;

        }

    }

    NDPI_LOG_INFO(ndpi_struct, "found syslog\n");

    ndpi_int_syslog_add_connection(ndpi_struct, flow);

    return;

  }

  NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

}

void init_syslog_dissector(struct ndpi_detection_module_struct *ndpi_struct)

{

  ndpi_register_dissector("Syslog", ndpi_struct,

                     ndpi_search_syslog,

                     NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,

                     1, NDPI_PROTOCOL_SYSLOG);

}