/* packet-locamation-im.c

 * Routines for Locamation Interface Modules packet disassembly.

 *

 * Copyright (c) 2022 Locamation BV.

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

/*

 * Locamation Interface Modules

 *

 * The modules send SNAP packets.

 *

 * Several types of IMs are supported:

 * - Current Interface Module (CIM), version 1

 * - Current Interface Module (CIM), version 2, revision 0

 * - Voltage Interface Module (VIM), version 1

 * - Voltage Interface Module (VIM), version 2, revision 0

 */

/* clang-format off */

#include "config.h"

#include <epan/packet.h>

/* clang-format on */

#include <epan/expert.h>

#include <epan/tfs.h>

#include <wsutil/array.h>

#include "packet-llc.h"

#ifndef ETH_FRAME_LEN

#define ETH_FRAME_LEN 1514 /* Max. octets in frame sans FCS */

#endif

/*

 * ########################################################################

 * #

 * # Forward Declarations

 * #

 * ########################################################################

 */

void proto_register_locamation_im(void);

void proto_reg_handoff_locamation_im(void);

/*

 * ########################################################################

 * #

 * # Defines

 * #

 * ########################################################################

 */

#define COMPANY_NAME "Locamation"

#define COMPANY_OUI 0x0040d6

#define COMPANY_IM_TEXT "Interface Module"

#define COMPANY_PID_CALIBRATION 0x0000

#define COMPANY_PID_IDENT 0xffff

#define COMPANY_PID_SAMPLES_IM1 0x0002

#define COMPANY_PID_SAMPLES_IM2R0 0x000e

#define PROTOCOL_NAME_IM_CALIBRATION "CALIBRATION"

#define PROTOCOL_NAME_IM_IDENT "IDENT"

#define PROTOCOL_NAME_IM_SAMPLES_IM1 "SAMPLES - IM1"

#define PROTOCOL_NAME_IM_SAMPLES_IM2R0 "SAMPLES - IM2R0"

#define PROTOCOL_NAME_CALIBRATION (COMPANY_NAME " " COMPANY_IM_TEXT " " PROTOCOL_NAME_IM_CALIBRATION)

#define PROTOCOL_NAME_IDENT (COMPANY_NAME " " COMPANY_IM_TEXT " " PROTOCOL_NAME_IM_IDENT)

#define PROTOCOL_NAME_SAMPLES_IM1 (COMPANY_NAME " " COMPANY_IM_TEXT " " PROTOCOL_NAME_IM_SAMPLES_IM1)

#define PROTOCOL_NAME_SAMPLES_IM2R0 (COMPANY_NAME " " COMPANY_IM_TEXT " " PROTOCOL_NAME_IM_SAMPLES_IM2R0)

#define PROTOCOL_SHORTNAME_CALIBRATION PROTOCOL_NAME_IM_CALIBRATION

#define PROTOCOL_SHORTNAME_IDENT PROTOCOL_NAME_IM_IDENT

#define PROTOCOL_SHORTNAME_SAMPLES_IM1 PROTOCOL_NAME_IM_SAMPLES_IM1

#define PROTOCOL_SHORTNAME_SAMPLES_IM2R0 PROTOCOL_NAME_IM_SAMPLES_IM2R0

#define MASK_SAMPLES_CONTROL_TYPE 0x80

#define MASK_SAMPLES_CONTROL_SIMULATED 0x40

#define MASK_SAMPLES_CONTROL_VERSION 0x30

#define MASK_SAMPLES_CONTROL_SEQUENCE_NUMBER 0x0f

#define MASK_RANGES_SAMPLE_8 0xc000

#define MASK_RANGES_SAMPLE_7 0x3000

#define MASK_RANGES_SAMPLE_6 0x0c00

#define MASK_RANGES_SAMPLE_5 0x0300

#define MASK_RANGES_SAMPLE_4 0x00c0

#define MASK_RANGES_SAMPLE_3 0x0030

#define MASK_RANGES_SAMPLE_2 0x000c

#define MASK_RANGES_SAMPLE_1 0x0003

#define MASK_TIMESTAMP_ADDITIONAL_STATUS_HOLDOVER_STATE 0x01

#define MASK_TIMESTAMP_ADDITIONAL_STATUS_MASTER_CLOCK_SWITCH 0x02

/*

 * ########################################################################

 * #

 * # PID Table

 * #

 * ########################################################################

 */

static const value_string company_pid_vals[] = {

    {COMPANY_PID_CALIBRATION, PROTOCOL_NAME_IM_CALIBRATION},

    {COMPANY_PID_IDENT, PROTOCOL_NAME_IM_IDENT},

    {COMPANY_PID_SAMPLES_IM1, PROTOCOL_NAME_IM_SAMPLES_IM1},

    {COMPANY_PID_SAMPLES_IM2R0, PROTOCOL_NAME_IM_SAMPLES_IM2R0},

    {0, NULL}};

/*

 * ########################################################################

 * #

 * # Types

 * #

 * ########################################################################

 */

/*

 * struct _sample_set_t {

 *  uint16_t ranges;

 *  int32_t sample_1;

 *  int32_t sample_2;

 *  int32_t sample_3;

 *  int32_t sample_4;

 *  int32_t sample_5;

 *  int32_t sample_6;

 *  int32_t sample_7;

 *  int32_t sample_8;

 * };

 */

#define SAMPLE_SET_SIZE 34

/*

 * struct _timestamp_t {

 *  uint8_t sync_status;

 *  uint8_t additional_status;

 *  uint32_t sec;

 *  uint32_t nsec;

 * };

 */

#define TIMESTAMP_SIZE 10

/*

 * struct _timestamps_t {

 *  uint8_t version;

 *  uint24_t reserved;

 *  struct _timestamp_t timestamps[8];

 * };

 */

#define TIMESTAMPS_SIZE 84

/*

 * ########################################################################

 * #

 * # Helpers

 * #

 * ########################################################################

 */

static void add_split_lines(packet_info *pinfo, tvbuff_t *tvb, int tvb_offset, proto_tree *tree, int hf) {

  int offset = tvb_offset;

  int next_offset;

  while (tvb_offset_exists(tvb, offset)) {

    int len = tvb_find_line_end(tvb, offset, -1, &next_offset, false);

    if (len == -1) {

      break;

    }

    char *line = (char*)tvb_get_string_enc(pinfo->pool, tvb, offset, len, ENC_UTF_8);

    proto_tree_add_string(tree, hf, tvb, offset, (next_offset - offset), line);

    offset = next_offset;

  }

}

/*

 * ########################################################################

 * #

 * # CALIBRATION

 * #

 * ########################################################################

 *

 * Calibration Packets

 *

 * Calibration Packets are sent by IM1 sensors.

 *

 * The calibration packets are sent in a burst, with a header packet

 * followed by a number of chunk packets. Both packet types start with a

 * Sequence Number.

 *

 * The calibration file can be reconstructed by appending all chunk packets

 * in the Sequence Number order.

 *

 * Sequence Number: 2 bytes, unsigned

 *   == 0: Header Packet

 *   != 0: Chunk Packet

 *

 * Header Packet

 * =============

 * Sequence Number      : 2 bytes, unsigned (fixed value 0)

 * First Sequence Number: 2 bytes, unsigned (fixed value 1)

 * Last Sequence Number : 2 bytes, unsigned (N)

 * Name                 : string

 *

 * Chunk Packet

 * ============

 * Sequence Number  : 2 bytes, unsigned (1 <= Sequence Number <= N)

 * Calibration Chunk: string

 */

static int hf_calibration_sequence_number;

static int hf_calibration_first_sequence_number;

static int hf_calibration_last_sequence_number;

static int hf_calibration_name;

static int hf_calibration_name_line;

static int hf_calibration_chunk;

static int hf_calibration_chunk_line;

static hf_register_info protocol_registration_calibration[] = {

    {&hf_calibration_sequence_number, {"Sequence Number", "locamation-im.calibration.sequence_number", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL}},

    {&hf_calibration_first_sequence_number, {"First Sequence Number", "locamation-im.calibration.first_sequence_number", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL}},

    {&hf_calibration_last_sequence_number, {"Last Sequence Number", "locamation-im.calibration.last_sequence_number", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL}},

    {&hf_calibration_name, {"Name", "locamation-im.calibration.name", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},

    {&hf_calibration_name_line, {"Name Line", "locamation-im.calibration.name.line", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},

    {&hf_calibration_chunk, {"Chunk", "locamation-im.calibration.chunk", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},

    {&hf_calibration_chunk_line, {"Chunk Line", "locamation-im.calibration.chunk.line", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}}};

static expert_field ei_calibration_header;

static ei_register_info ei_calibration[] = {

    {&ei_calibration_header, {"locamation-im.calibration.header", PI_SEQUENCE, PI_NOTE, "Header Packet", EXPFILL}}};

static int h_protocol_calibration = -1;

static int ett_protocol_calibration;

static int ett_calibration_lines;

static int dissect_calibration(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {

  col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTOCOL_SHORTNAME_CALIBRATION);

  col_set_str(pinfo->cinfo, COL_INFO, PROTOCOL_NAME_CALIBRATION);

  proto_item *calibration_item = proto_tree_add_item(tree, h_protocol_calibration, tvb, 0, -1, ENC_NA);

  proto_tree *calibration_item_subtree = proto_item_add_subtree(calibration_item, ett_protocol_calibration);

  int tvb_offset = 0;

  /* Sequence Number */

  int item_size = 2;

  tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

  uint16_t sequence_number = tvb_get_uint16(tvb, 0, ENC_BIG_ENDIAN);

  if (sequence_number == 0) {

    expert_add_info(pinfo, calibration_item, &ei_calibration_header);

  }

  proto_tree_add_item(calibration_item_subtree, hf_calibration_sequence_number, tvb, tvb_offset, item_size, ENC_BIG_ENDIAN);

  tvb_offset += item_size;

  if (sequence_number == 0) {

    /* Header Packet */

    /* First Sequence Number */

    item_size = 2;

    tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

    proto_tree_add_item(calibration_item_subtree, hf_calibration_first_sequence_number, tvb, tvb_offset, item_size, ENC_BIG_ENDIAN);

    tvb_offset += item_size;

    /* Last Sequence Number */

    item_size = 2;

    tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

    proto_tree_add_item(calibration_item_subtree, hf_calibration_last_sequence_number, tvb, tvb_offset, item_size, ENC_BIG_ENDIAN);

    tvb_offset += item_size;

    /* Name */

    int name_length = tvb_reported_length_remaining(tvb, tvb_offset);

    proto_item *name_item = proto_tree_add_item(calibration_item_subtree, hf_calibration_name, tvb, tvb_offset, name_length, ENC_UTF_8);

    /* Name - Lines */

    proto_tree *name_item_subtree = proto_item_add_subtree(name_item, ett_calibration_lines);

    add_split_lines(pinfo, tvb, tvb_offset, name_item_subtree, hf_calibration_name_line);

  } else {

    /* Chunk Packet */

    /* Chunk */

    int chunk_length = tvb_reported_length_remaining(tvb, tvb_offset);

    proto_item *chunk_item = proto_tree_add_item(calibration_item_subtree, hf_calibration_chunk, tvb, tvb_offset, chunk_length, ENC_UTF_8);

    /* Chunk - Lines */

    proto_tree *chunk_item_subtree = proto_item_add_subtree(chunk_item, ett_calibration_lines);

    add_split_lines(pinfo, tvb, tvb_offset, chunk_item_subtree, hf_calibration_chunk_line);

  }

  return tvb_captured_length(tvb);

}

/*

 * ########################################################################

 * #

 * # IDENT

 * #

 * ########################################################################

 *

 * Ident Packets

 *

 * Ident Packets are sent by IM1 and IM2R0 sensors.

 *

 * Ident Packet

 * ============

 * Content: string

 */

static int hf_ident_contents;

static int hf_ident_contents_line;

static hf_register_info protocol_registration_ident[] = {

    {&hf_ident_contents, {"Contents", "locamation-im.ident.contents", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},

    {&hf_ident_contents_line, {"Contents Line", "locamation-im.ident.contents.line", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}}};

static int h_protocol_ident = -1;

static int ett_protocol_ident;

static int ett_ident_lines;

static int dissect_ident(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {

  col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTOCOL_SHORTNAME_IDENT);

  col_set_str(pinfo->cinfo, COL_INFO, PROTOCOL_NAME_IDENT);

  proto_item *ident_item = proto_tree_add_item(tree, h_protocol_ident, tvb, 0, -1, ENC_NA);

  proto_tree *ident_item_subtree = proto_item_add_subtree(ident_item, ett_protocol_ident);

  /* Contents */

  int contents_length = tvb_reported_length_remaining(tvb, 0);

  proto_item *contents_item = proto_tree_add_item(ident_item_subtree, hf_ident_contents, tvb, 0, contents_length, ENC_UTF_8);

  /* Contents - Lines */

  proto_tree *contents_item_subtree = proto_item_add_subtree(contents_item, ett_ident_lines);

  add_split_lines(pinfo, tvb, 0, contents_item_subtree, hf_ident_contents_line);

  return tvb_captured_length(tvb);

}

/*

 * ########################################################################

 * #

 * # SAMPLES - Common

 * #

 * ########################################################################

 */

static expert_field ei_samples_ranges_sample_1_invalid;

static expert_field ei_samples_ranges_sample_2_invalid;

static expert_field ei_samples_ranges_sample_3_invalid;

static expert_field ei_samples_ranges_sample_4_invalid;

static expert_field ei_samples_ranges_sample_5_invalid;

static expert_field ei_samples_ranges_sample_6_invalid;

static expert_field ei_samples_ranges_sample_7_invalid;

static expert_field ei_samples_ranges_sample_8_invalid;

static void check_ranges(tvbuff_t *tvb, packet_info *pinfo, int tvb_offset, proto_item *item) {

  uint16_t ranges = tvb_get_uint16(tvb, tvb_offset, ENC_BIG_ENDIAN);

  if ((ranges & MASK_RANGES_SAMPLE_8) == MASK_RANGES_SAMPLE_8) {

    expert_add_info(pinfo, item, &ei_samples_ranges_sample_8_invalid);

  }

  if ((ranges & MASK_RANGES_SAMPLE_7) == MASK_RANGES_SAMPLE_7) {

    expert_add_info(pinfo, item, &ei_samples_ranges_sample_7_invalid);

  }

  if ((ranges & MASK_RANGES_SAMPLE_6) == MASK_RANGES_SAMPLE_6) {

    expert_add_info(pinfo, item, &ei_samples_ranges_sample_6_invalid);

  }

  if ((ranges & MASK_RANGES_SAMPLE_5) == MASK_RANGES_SAMPLE_5) {

    expert_add_info(pinfo, item, &ei_samples_ranges_sample_5_invalid);

  }

  if ((ranges & MASK_RANGES_SAMPLE_4) == MASK_RANGES_SAMPLE_4) {

    expert_add_info(pinfo, item, &ei_samples_ranges_sample_4_invalid);

  }

  if ((ranges & MASK_RANGES_SAMPLE_3) == MASK_RANGES_SAMPLE_3) {

    expert_add_info(pinfo, item, &ei_samples_ranges_sample_3_invalid);

  }

  if ((ranges & MASK_RANGES_SAMPLE_2) == MASK_RANGES_SAMPLE_2) {

    expert_add_info(pinfo, item, &ei_samples_ranges_sample_2_invalid);

  }

  if ((ranges & MASK_RANGES_SAMPLE_1) == MASK_RANGES_SAMPLE_1) {

    expert_add_info(pinfo, item, &ei_samples_ranges_sample_1_invalid);

  }

}

static int ett_samples_sample_set_ranges;

static int hf_samples_sample_set_ranges;

static int hf_samples_sample_set_ranges_sample_1;

static int hf_samples_sample_set_ranges_sample_2;

static int hf_samples_sample_set_ranges_sample_3;

static int hf_samples_sample_set_ranges_sample_4;

static int hf_samples_sample_set_ranges_sample_5;

static int hf_samples_sample_set_ranges_sample_6;

static int hf_samples_sample_set_ranges_sample_7;

static int hf_samples_sample_set_ranges_sample_8;

static int *const rangesBits[] = {

    &hf_samples_sample_set_ranges_sample_8,

    &hf_samples_sample_set_ranges_sample_7,

    &hf_samples_sample_set_ranges_sample_6,

    &hf_samples_sample_set_ranges_sample_5,

    &hf_samples_sample_set_ranges_sample_4,

    &hf_samples_sample_set_ranges_sample_3,

    &hf_samples_sample_set_ranges_sample_2,

    &hf_samples_sample_set_ranges_sample_1,

    NULL};

static int hf_samples_sample_set_sample_1;

static int hf_samples_sample_set_sample_2;

static int hf_samples_sample_set_sample_3;

static int hf_samples_sample_set_sample_4;

static int hf_samples_sample_set_sample_5;

static int hf_samples_sample_set_sample_6;

static int hf_samples_sample_set_sample_7;

static int hf_samples_sample_set_sample_8;

static void add_sample_set(tvbuff_t *tvb, packet_info *pinfo, int *tvb_offset, int hf, proto_tree *tree) {

  int item_size = SAMPLE_SET_SIZE;

  tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

  proto_item *sample_set_item = proto_tree_add_item(tree, hf, tvb, *tvb_offset, item_size, ENC_BIG_ENDIAN);

  proto_tree *sample_set_item_subtree = proto_item_add_subtree(sample_set_item, ett_samples_sample_set_ranges);

  /* Ranges */

  item_size = 2;

  tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

  proto_item *ranges_item = proto_tree_add_bitmask(sample_set_item_subtree, tvb, *tvb_offset, hf_samples_sample_set_ranges, ett_samples_sample_set_ranges, rangesBits, ENC_BIG_ENDIAN);

  check_ranges(tvb, pinfo, *tvb_offset, ranges_item);

  *tvb_offset += item_size;

  /* Samples */

  int const hfs[] = {

      hf_samples_sample_set_sample_1,

      hf_samples_sample_set_sample_2,

      hf_samples_sample_set_sample_3,

      hf_samples_sample_set_sample_4,

      hf_samples_sample_set_sample_5,

      hf_samples_sample_set_sample_6,

      hf_samples_sample_set_sample_7,

      hf_samples_sample_set_sample_8};

  item_size = 4;

  for (unsigned index_sample = 0; index_sample < array_length(hfs); index_sample++) {

    tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

    proto_tree_add_item(sample_set_item_subtree, hfs[index_sample], tvb, *tvb_offset, item_size, ENC_BIG_ENDIAN);

    *tvb_offset += item_size;

  }

}

static void add_sample_sets(tvbuff_t *tvb, packet_info *pinfo, int *tvb_offset, int *hfs, unsigned hfs_size, proto_tree *tree) {

  for (unsigned index_sample_set = 0; index_sample_set < hfs_size; index_sample_set++) {

    add_sample_set(tvb, pinfo, tvb_offset, hfs[index_sample_set], tree);

  }

}

static void add_rms_values(tvbuff_t *tvb, int *tvb_offset, int *hfs, unsigned hfs_size, proto_tree *tree) {

  int item_size = 4;

  for (unsigned index_rms_value = 0; index_rms_value < hfs_size; index_rms_value++) {

    tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

    proto_tree_add_item(tree, hfs[index_rms_value], tvb, *tvb_offset, item_size, ENC_BIG_ENDIAN);

    *tvb_offset += item_size;

  }

}

static int ett_samples_timestamps_sample;

static int ett_samples_timestamps_sample_reserved;

static int ett_samples_timestamps_sample_timestamp;

static int hf_samples_timestamps_sample_sync_status;

static int hf_samples_timestamps_sample_additional_status;

static int hf_samples_timestamps_sample_additional_status_holdover_state;

static int hf_samples_timestamps_sample_additional_status_master_clock_switch;

static int hf_samples_timestamps_sample_timestamp;

static int hf_samples_timestamps_sample_timestamp_seconds;

static int hf_samples_timestamps_sample_timestamp_nanoseconds;

static const value_string samples_timestamps_sample_sync_status[] = {

    {0, "None"},

    {1, "Local"},

    {2, "Global"},

    {0, NULL}};

static int *const timestamp_additional_status_bits[] = {

    &hf_samples_timestamps_sample_additional_status_holdover_state,

    &hf_samples_timestamps_sample_additional_status_master_clock_switch,

    NULL};

static expert_field ei_samples_timestamp_sync_status_invalid;

static void add_timestamp_sample(tvbuff_t *tvb, packet_info *pinfo, int *tvb_offset_previous, int *tvb_offset, int hf, proto_tree *tree) {

  int item_size = TIMESTAMP_SIZE;

  tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

  /* Get the timestamp components */

  uint8_t sync_status = tvb_get_uint8(tvb, *tvb_offset);

  uint32_t seconds = tvb_get_uint32(tvb, *tvb_offset + 2, ENC_BIG_ENDIAN);

  uint32_t nanoseconds = tvb_get_uint32(tvb, *tvb_offset + 6, ENC_BIG_ENDIAN);

  /* Convert the timestamp seconds to a split time type */

  time_t sample_time = (time_t)seconds;

  struct tm *sample_time_split = gmtime(&sample_time);

  /* Construct the readable sync status */

  const char *sync_status_buf = val_to_str(pinfo->pool, sync_status, samples_timestamps_sample_sync_status, "Unknown (%u)");

  /* Construct the readable timestamp */

  char timestamp_buf[ITEM_LABEL_LENGTH];

  size_t timestamp_length = 0;

  if (sample_time_split != NULL) {

    timestamp_length += strftime(&timestamp_buf[timestamp_length], ITEM_LABEL_LENGTH - timestamp_length, "%Y-%m-%d %H:%M:%S.", sample_time_split);

  } else {

    timestamp_length += snprintf(&timestamp_buf[timestamp_length], ITEM_LABEL_LENGTH - timestamp_length, "\?\?\?\?-\?\?-\?\? \?\?:\?\?:\?\?.");

  }

  snprintf(&timestamp_buf[timestamp_length], ITEM_LABEL_LENGTH - timestamp_length, "%09u TAI", nanoseconds);

  /* Construct the readable sample text */

  char title_buf[ITEM_LABEL_LENGTH];

  size_t title_length = 0;

  title_length += snprintf(&title_buf[title_length], ITEM_LABEL_LENGTH - title_length, "%s (Sync: %s", timestamp_buf, sync_status_buf);

  if (tvb_offset_previous != NULL) {

    /* Get the previous timestamp components and calculate the time difference */

    uint32_t seconds_previous = tvb_get_uint32(tvb, *tvb_offset_previous + 2, ENC_BIG_ENDIAN);

    uint32_t nanoseconds_previous = tvb_get_uint32(tvb, *tvb_offset_previous + 6, ENC_BIG_ENDIAN);

    uint64_t time_previous = ((uint64_t)seconds_previous * 1000000000) + nanoseconds_previous;

    uint64_t time_now = ((uint64_t)seconds * 1000000000) + nanoseconds;

    uint64_t time_diff = 0;

    char time_difference_sign[2] = {'\0', '\0'};

    if (time_now > time_previous) {

      time_diff = time_now - time_previous;

      time_difference_sign[0] = '\0';

    } else if (time_now < time_previous) {

      time_diff = time_previous - time_now;

      time_difference_sign[0] = '-';

    }

    double frequency = 0.0;

    if (time_diff != 0) {

      frequency = 1.0 / ((double)time_diff * 1.0E-09);

    }

    title_length += snprintf(&title_buf[title_length], ITEM_LABEL_LENGTH - title_length, ", Time Difference: %s%" PRIu64 " nsec", time_difference_sign, time_diff);

    if (frequency != 0.0) {

      title_length += snprintf(&title_buf[title_length], ITEM_LABEL_LENGTH - title_length, " = %f Hz", frequency);

    }

  }

  snprintf(&title_buf[title_length], ITEM_LABEL_LENGTH - title_length, ")");

  proto_item *sample_timestamp_item = proto_tree_add_string(tree, hf, tvb, *tvb_offset, item_size, title_buf);

  proto_tree *sample_timestamp_item_subtree = proto_item_add_subtree(sample_timestamp_item, ett_samples_timestamps_sample);

  /* Sync Status */

  item_size = 1;

  tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

  proto_item *sync_status_item = proto_tree_add_item(sample_timestamp_item_subtree, hf_samples_timestamps_sample_sync_status, tvb, *tvb_offset, item_size, ENC_BIG_ENDIAN);

  *tvb_offset += item_size;

  if (sync_status > 2) {

    expert_add_info(pinfo, sync_status_item, &ei_samples_timestamp_sync_status_invalid);

  }

  /* Additional Status */

  item_size = 1;

  tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

  proto_tree_add_bitmask(sample_timestamp_item_subtree, tvb, *tvb_offset, hf_samples_timestamps_sample_additional_status, ett_samples_timestamps_sample_reserved, timestamp_additional_status_bits, ENC_BIG_ENDIAN);

  *tvb_offset += item_size;

  /* Timestamp */

  item_size = 8;

  tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

  proto_item *sample_timestamp_timestamp_item = proto_tree_add_string(sample_timestamp_item_subtree, hf_samples_timestamps_sample_timestamp, tvb, *tvb_offset, item_size, timestamp_buf);

  proto_tree *sample_timestamp_timestamp_item_subtree = proto_item_add_subtree(sample_timestamp_timestamp_item, ett_samples_timestamps_sample_timestamp);

  /* Seconds */

  item_size = 4;

  tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

  proto_tree_add_item(sample_timestamp_timestamp_item_subtree, hf_samples_timestamps_sample_timestamp_seconds, tvb, *tvb_offset, item_size, ENC_BIG_ENDIAN);

  *tvb_offset += item_size;

  /* Nanoseconds */

  item_size = 4;

  tvb_ensure_bytes_exist(tvb, *tvb_offset, item_size);

  proto_tree_add_item(sample_timestamp_timestamp_item_subtree, hf_samples_timestamps_sample_timestamp_nanoseconds, tvb, *tvb_offset, item_size, ENC_BIG_ENDIAN);

  *tvb_offset += item_size;

}

static void add_timestamps_set(tvbuff_t *tvb, packet_info *pinfo, int *tvb_offset, int *hfs, unsigned hfs_size, proto_tree *tree) {

  int tvb_offset_previous = 0;

  for (unsigned index_timestamp = 0; index_timestamp < hfs_size; index_timestamp++) {

    int tvb_offset_saved = *tvb_offset;

    add_timestamp_sample(tvb, pinfo, (index_timestamp == 0) ? NULL : &tvb_offset_previous, tvb_offset, hfs[index_timestamp], tree);

    tvb_offset_previous = tvb_offset_saved;

  }

}

/*

 * Samples Packets

 *

 * Samples Packets are sent by IM1 and IM2R0 sensors.

 * However, details of the packets differ between the sensors.

 *

 * Samples Packet

 * ==============

 * Transport Delay: 2 bytes, unsigned (resolution = 10ns)

 * Hop Count: 1 byte, unsigned

 * Control data: 1 byte, bitmap

 *   bit  [7]   : type     : 0 = CIM, 1 = VIM

 *   bit  [6]   : simulated: 0 = Real Samples, 1 = Simulated Samples

 *   bits [5..4]: version  : 00 = IM1, 11 = IM2R0

 *   bits [3..0]: seqnr    : Sequence Number, in the range [0,15], monotonically

 *                           increasing and wrapping

 * Temperature: 2 bytes, signed (resolution = 0.25C)

 * Padding: 1 byte

 * ADC Status: 1 byte, unsigned

 * Sample Data

 *   * Sample data is stored in sample data sets.

 *     Each sample data set contains ranges and the data of 8 samples, and

 *     samples are equi-distant in time.

 *

 *     Sample Data Set

 *     ===============

 *       Range: 2 bytes, bitmap

 *              - bits [15,14]: Range of sample 8 (newest sample)

 *              - bits [13,12]: Range of sample 7

 *              - bits [11,10]: Range of sample 6

 *              - bits [ 9, 8]: Range of sample 5

 *              - bits [ 7, 6]: Range of sample 4

 *              - bits [ 5, 4]: Range of sample 3

 *              - bits [ 3, 2]: Range of sample 2

 *              - bits [ 1, 0]: Range of sample 1 (oldest sample)

 *              Range values:

 *                00 = measurement ADC channel

 *                01 = protection ADC channel, range low

 *                10 = protection ADC channel, range high

 *                11 = unused

 *       Sample 1: 4 bytes, signed (oldest sample)

 *       Sample 2: 4 bytes, signed

 *       Sample 3: 4 bytes, signed

 *       Sample 4: 4 bytes, signed

 *       Sample 5: 4 bytes, signed

 *       Sample 6: 4 bytes, signed

 *       Sample 7: 4 bytes, signed

 *       Sample 8: 4 bytes, signed (newest sample)

 *

 *   * IM1

 *     6 sample data sets, one set per ADC channel:

 *

 *     Sample Data

 *     ===========

 *              CIM                             VIM

 *     set 1    channel 1, measurement          channel 1

 *     set 2    channel 2, measurement          channel 2

 *     set 3    channel 3, measurement          channel 3

 *     set 4    channel 1, protection           0

 *     set 5    channel 2, protection           0

 *     set 6    channel 3, protection           0

 *

 *   * IM2R0

 *     8 sample data sets, one set per ADC channel:

 *

 *     Sample Data

 *     ===========

 *              CIM                             VIM

 *     set 1    channel 1, measurement          channel 1

 *     set 2    channel 2, measurement          channel 2

 *     set 3    channel 3, measurement          channel 3

 *     set 4    channel 1, protection           neutral channel

 *     set 5    channel 2, protection           0

 *     set 6    channel 3, protection           0

 *     set 7    neutral channel, measurement    0

 *     set 8    neutral channel, protection     0

 * RMS values

 *   * RMS values are stored as 4 byte signed values.

 *

 *   * IM1

 *     6 values, one per ADC-channel:

 *

 *     RMS values

 *     ==========

 *              CIM                             VIM

 *     value 1  channel 1, measurement          channel 1

 *     value 2  channel 2, measurement          channel 2

 *     value 3  channel 3, measurement          channel 3

 *     value 4  channel 1, protection           0

 *     value 5  channel 2, protection           0

 *     value 6  channel 3, protection           0

 *

 *   * IM2R0

 *     8 values, one per ADC-channel:

 *

 *     RMS values

 *     ==========

 *              CIM                             VIM

 *     value 1  0                               0

 *     value 2  0                               0

 *     value 3  0                               0

 *     value 4  0                               0

 *     value 5  0                               0

 *     value 6  0                               0

 *     value 7  0                               0

 *     value 8  0                               0

 * Timestamps

 *   * Timestamps are PTP driven and are stored in a versioned block.

 *     Each timestamp also has status information.

 *

 *   * IM1

 *     Timestamps are not applicable for IM1.

 *

 *   * IM2R0

 *     Timestamps are optional.

 *

 *     Timestamps Block

 *     ================

 *     Version   1 byte, unsigned

 *     Reserved  3 bytes, unsigned

 *     Sample 1  Timestamp (oldest sample)

 *     Sample 2  Timestamp

 *     Sample 3  Timestamp

 *     Sample 4  Timestamp

 *     Sample 5  Timestamp

 *     Sample 6  Timestamp

 *     Sample 7  Timestamp

 *     Sample 8  Timestamp (newest sample)

 *

 *     Timestamp

 *     =========

 *     Sync Status  1 byte, unsigned

 *       0     = Not synchronized (during start-up or synchronization lost)

 *       1     = Synchronized but not to a Grand Master Clock

 *       2     = Synchronized to a Grand Master Clock

 *       3-255 = Invalid

 *     Additional Status  1 byte, bitmap

 *       bits [7, 2]: Reserved

 *       bits [1]   : Master clock switch

 *         1 = The device switched to a different master clock or

 *             became synchronized to a master clock for the first time.

 *         0 = The device did not switch to a different master clock nor

 *             became synchronized to a master clock for the first time.

 *       bits [0]   : Holdover state

 *         1 = The device is in its holdover state.

 *         0 = The device is not in its holdover state.

 *     Seconds      4 bytes, unsigned

 *     Nanoseconds  4 bytes, unsigned

 */

static int ett_protocol_samples;

static int ett_samples_control;

static int ett_samples_sets;

static int ett_samples_sets_set;

static int ett_samples_rms;

static int ett_samples_rms_values;

static int ett_samples_timestamps;

static int ett_samples_timestamps_set;

static expert_field ei_samples_im_version_invalid;

static int hf_samples_transport_delay;

static int hf_samples_hop_count;

static int hf_samples_control;

static int hf_samples_control_type;

static int hf_samples_control_simulated;

static int hf_samples_control_version;

static int hf_samples_control_sequence_number;

static int hf_samples_temperature;

static int hf_samples_padding;

static int hf_samples_adc_status;

static int hf_samples_sample_set;

static int hf_samples_rms_values;

static int hf_samples_timestamps;

static int *const controlBits[] = {

    &hf_samples_control_type,

    &hf_samples_control_simulated,

    &hf_samples_control_version,

    &hf_samples_control_sequence_number,

    NULL};

static int hf_samples_sample_set_measurement_channel_1;

static int hf_samples_sample_set_measurement_channel_2;

static int hf_samples_sample_set_measurement_channel_3;

static int hf_samples_sample_set_measurement_channel_n;

static int hf_samples_sample_set_protection_channel_1;

static int hf_samples_sample_set_protection_channel_2;

static int hf_samples_sample_set_protection_channel_3;

static int hf_samples_sample_set_protection_channel_n;

static int hf_samples_sample_set_channel_unused;

static int hf_samples_rms_values_measurement_channel_1;

static int hf_samples_rms_values_measurement_channel_2;

static int hf_samples_rms_values_measurement_channel_3;

static int hf_samples_rms_values_protection_channel_1;

static int hf_samples_rms_values_protection_channel_2;

static int hf_samples_rms_values_protection_channel_3;

static int hf_samples_rms_values_channel_unused;

static int hf_samples_timestamps_version;

static int hf_samples_timestamps_reserved;

static int hf_samples_timestamps_sample_1;

static int hf_samples_timestamps_sample_2;

static int hf_samples_timestamps_sample_3;

static int hf_samples_timestamps_sample_4;

static int hf_samples_timestamps_sample_5;

static int hf_samples_timestamps_sample_6;

static int hf_samples_timestamps_sample_7;

static int hf_samples_timestamps_sample_8;

static int dissect_samples_im(bool im1, tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_, int h_protocol_samples) {

  col_set_str(pinfo->cinfo, COL_PROTOCOL, im1 ? PROTOCOL_SHORTNAME_SAMPLES_IM1 : PROTOCOL_SHORTNAME_SAMPLES_IM2R0);

  col_set_str(pinfo->cinfo, COL_INFO, im1 ? PROTOCOL_NAME_SAMPLES_IM1 : PROTOCOL_NAME_SAMPLES_IM2R0);

  proto_item *samples_item = proto_tree_add_item(tree, h_protocol_samples, tvb, 0, -1, ENC_NA);

  proto_tree *samples_item_subtree = proto_item_add_subtree(samples_item, ett_protocol_samples);

  int tvb_offset = 0;

  /* Transport Delay */

  int item_size = 2;

  tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

  proto_tree_add_item(samples_item_subtree, hf_samples_transport_delay, tvb, tvb_offset, item_size, ENC_BIG_ENDIAN);

  tvb_offset += item_size;

  /* Hop Count */

  item_size = 1;

  tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

  proto_tree_add_item(samples_item_subtree, hf_samples_hop_count, tvb, tvb_offset, item_size, ENC_BIG_ENDIAN);

  tvb_offset += item_size;

  /* Get Control */

  uint8_t control = tvb_get_uint8(tvb, tvb_offset);

  bool isIM1 = ((control & MASK_SAMPLES_CONTROL_VERSION) == 0);

  bool isIM2R0 = ((control & MASK_SAMPLES_CONTROL_VERSION) == MASK_SAMPLES_CONTROL_VERSION);

  bool isCIM = ((control & MASK_SAMPLES_CONTROL_TYPE) == 0);

  /* Control */

  item_size = 1;

  tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

  proto_item *control_item = proto_tree_add_bitmask(samples_item_subtree, tvb, tvb_offset, hf_samples_control, ett_samples_control, controlBits, ENC_BIG_ENDIAN);

  tvb_offset += item_size;

  if (!isIM1 && !isIM2R0) {

    expert_add_info(pinfo, control_item, &ei_samples_im_version_invalid);

  }

  /* Temperature */

  item_size = 2;

  tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

  proto_tree_add_item(samples_item_subtree, hf_samples_temperature, tvb, tvb_offset, item_size, ENC_BIG_ENDIAN);

  tvb_offset += item_size;

  /* Padding */

  item_size = 1;

  tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

  proto_tree_add_item(samples_item_subtree, hf_samples_padding, tvb, tvb_offset, item_size, ENC_BIG_ENDIAN);

  tvb_offset += item_size;

  /* ADC status */

  item_size = 1;

  tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

  proto_tree_add_item(samples_item_subtree, hf_samples_adc_status, tvb, tvb_offset, item_size, ENC_BIG_ENDIAN);

  tvb_offset += item_size;

  /* Sample Sets */

  {

    proto_tree *sample_sets_subtree = proto_item_add_subtree(samples_item, ett_samples_sets);

    if (im1) {

      item_size = SAMPLE_SET_SIZE * 6;

    } else {

      item_size = SAMPLE_SET_SIZE * 8;

    }

    tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

    proto_item *sample_sets_subtree_item = proto_tree_add_item(sample_sets_subtree, hf_samples_sample_set, tvb, tvb_offset, item_size, ENC_NA);

    proto_tree *sample_sets_subtree_item_subtree = proto_item_add_subtree(sample_sets_subtree_item, ett_samples_sets_set);

    if (isIM1) {

      if (isCIM) {

        /* IM1 CIM */

        int hfs[] = {

            hf_samples_sample_set_measurement_channel_1,

            hf_samples_sample_set_measurement_channel_2,

            hf_samples_sample_set_measurement_channel_3,

            hf_samples_sample_set_protection_channel_1,

            hf_samples_sample_set_protection_channel_2,

            hf_samples_sample_set_protection_channel_3};

        add_sample_sets(tvb, pinfo, &tvb_offset, hfs, array_length(hfs), sample_sets_subtree_item_subtree);

      } else {

        /* IM1 VIM */

        int hfs[] = {

            hf_samples_sample_set_measurement_channel_1,

            hf_samples_sample_set_measurement_channel_2,

            hf_samples_sample_set_measurement_channel_3,

            hf_samples_sample_set_channel_unused,

            hf_samples_sample_set_channel_unused,

            hf_samples_sample_set_channel_unused};

        add_sample_sets(tvb, pinfo, &tvb_offset, hfs, array_length(hfs), sample_sets_subtree_item_subtree);

      }

    } else if (isIM2R0) {

      if (isCIM) {

        /* IM2R0 CIM */

        int hfs[] = {

            hf_samples_sample_set_measurement_channel_1,

            hf_samples_sample_set_measurement_channel_2,

            hf_samples_sample_set_measurement_channel_3,

            hf_samples_sample_set_protection_channel_1,

            hf_samples_sample_set_protection_channel_2,

            hf_samples_sample_set_protection_channel_3,

            hf_samples_sample_set_measurement_channel_n,

            hf_samples_sample_set_protection_channel_n};

        add_sample_sets(tvb, pinfo, &tvb_offset, hfs, array_length(hfs), sample_sets_subtree_item_subtree);

      } else {

        /* IM2R0 VIM */

        int hfs[] = {

            hf_samples_sample_set_measurement_channel_1,

            hf_samples_sample_set_measurement_channel_2,

            hf_samples_sample_set_measurement_channel_3,

            hf_samples_sample_set_measurement_channel_n,

            hf_samples_sample_set_channel_unused,

            hf_samples_sample_set_channel_unused,

            hf_samples_sample_set_channel_unused,

            hf_samples_sample_set_channel_unused};

        add_sample_sets(tvb, pinfo, &tvb_offset, hfs, array_length(hfs), sample_sets_subtree_item_subtree);

      }

    }

  }

  /* RMS Values */

  {

    proto_tree *rms_values_subtree = proto_item_add_subtree(samples_item, ett_samples_rms);

    if (im1) {

      item_size = 4 * 6;

    } else {

      item_size = 4 * 8;

    }

    tvb_ensure_bytes_exist(tvb, tvb_offset, item_size);

    proto_item *rms_values_item = proto_tree_add_item(rms_values_subtree, hf_samples_rms_values, tvb, tvb_offset, item_size, ENC_NA);

    proto_tree *rms_values_item_subtree = proto_item_add_subtree(rms_values_item, ett_samples_rms_values);

    if (isIM1) {

      if (isCIM) {

        /* IM1 CIM */

        int hfs[] = {

            hf_samples_rms_values_measurement_channel_1,

            hf_samples_rms_values_measurement_channel_2,

            hf_samples_rms_values_measurement_channel_3,

            hf_samples_rms_values_protection_channel_1,

            hf_samples_rms_values_protection_channel_2,

            hf_samples_rms_values_protection_channel_3};

        add_rms_values(tvb, &tvb_offset, hfs, array_length(hfs), rms_values_item_subtree);

      } else {

        /* IM1 VIM */

        int hfs[] = {

            hf_samples_rms_values_measurement_channel_1,

            hf_samples_rms_values_measurement_channel_2,

            hf_samples_rms_values_measurement_channel_3,

            hf_samples_rms_values_channel_unused,

            hf_samples_rms_values_channel_unused,

            hf_samples_rms_values_channel_unused};

        add_rms_values(tvb, &tvb_offset, hfs, array_length(hfs), rms_values_item_subtree);

      }

    } else if (isIM2R0) {

      int hfs[] = {

          hf_samples_rms_values_channel_unused,

          hf_samples_rms_values_channel_unused,

          hf_samples_rms_values_channel_unused,

          hf_samples_rms_values_channel_unused,

          hf_samples_rms_values_channel_unused,

          hf_samples_rms_values_channel_unused,