/*

 * hl7.c

 *

 * Health Level Seven (HL7)

 * 

 * Copyright (C) 2023 - ntop.org

 * Copyright (C) 2023 - V.G <v.gavrilov@securitycode.ru>

 *

 * 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_HL7

#include "ndpi_api.h"

#include "ndpi_private.h"

static void ndpi_search_hl7(struct ndpi_detection_module_struct *ndpi_struct,

                            struct ndpi_flow_struct *flow)

{

  struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;

  NDPI_LOG_DBG(ndpi_struct, "search HL7\n");

  if (flow->detected_protocol_stack[0] == NDPI_PROTOCOL_HTTP ||

      flow->detected_protocol_stack[1] == NDPI_PROTOCOL_HTTP)

  {

    if (packet->content_line.ptr != NULL) {

      if ((LINE_ENDS(packet->content_line, "x-application/hl7-v2+er7") != 0) ||

          (LINE_ENDS(packet->content_line, "x-application/hl7-v2+xml") != 0) ||

          (LINE_ENDS(packet->content_line, "x-application/hl7-v3+xml") != 0) ||

          (LINE_ENDS(packet->content_line, "x-application/fhir+xml") != 0)   ||

          (LINE_ENDS(packet->content_line, "x-application/fhir+json") != 0)  ||

          (LINE_ENDS(packet->content_line, "x-application/xml+cda") != 0))

      {

        NDPI_LOG_INFO(ndpi_struct, "found HL7 over HTTP\n");

        ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_HL7, NDPI_PROTOCOL_HTTP, 

                                   NDPI_CONFIDENCE_DPI);

      }

    }

    return;

  }

  if (packet->payload_packet_len > 100 &&

      memcmp(&packet->payload[1], "MSH|^~\\&|", NDPI_STATICSTRING_LEN("MSH|^~\\&|")) == 0)

  {

    NDPI_LOG_INFO(ndpi_struct, "found HL7\n");

    ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_HL7, NDPI_PROTOCOL_UNKNOWN, 

                               NDPI_CONFIDENCE_DPI);

    return;

  }

  NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

}

void init_hl7_dissector(struct ndpi_detection_module_struct *ndpi_struct)

{

  ndpi_register_dissector("HL7", ndpi_struct,

                     ndpi_search_hl7,

                     NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,

                     1, NDPI_PROTOCOL_HL7);

}