/*
 * 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_PROTO(ndpi_struct, flow);
}

void init_hl7_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id)
{
  ndpi_set_bitmask_protocol_detection("HL7", ndpi_struct, *id,
              NDPI_PROTOCOL_HL7,
              ndpi_search_hl7,
              NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
              SAVE_DETECTION_BITMASK_AS_UNKNOWN,
              ADD_TO_DETECTION_BITMASK);

  *id += 1;
}