/* packet-cisco-marker.c

 * Routines for CISCO's ERSPAN3 Marker Packet

 * See: http://www.cisco.com/c/en/us/products/collateral/switches/nexus-9000-series-switches/white-paper-c11-733921.html#_Toc413144488

 * See: https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/93x/system-management/b-cisco-nexus-9000-series-nx-os-system-management-configuration-guide-93x/b-cisco-nexus-9000-series-nx-os-system-management-configuration-guide-93x_chapter_011110.html

 * Copyright 2015, Peter Membrey

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * Copied from packet-time.c

 * Fixed with additional documentation from Cisco and real-life observations

 * by Stéphane Lapie <stephane.lapie@darkbsd.org>

 *

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

 */

#include "config.h"

#include <epan/packet.h>

void proto_register_erspan_marker(void);

void proto_reg_handoff_erspan_marker(void);

static dissector_handle_t marker_handle;

static int proto_marker;

static int hf_cisco_erspan_granularity;

static int hf_cisco_erspan_info;

static int hf_cisco_erspan_prop_header;

static int hf_cisco_erspan_reserved;

static int hf_cisco_erspan_sequence_number;

static int hf_cisco_erspan_ssid;

static int hf_cisco_erspan_tail;

static int hf_cisco_erspan_timestamp;

static int hf_cisco_erspan_type;

static int hf_cisco_erspan_utc_sec;

static int hf_cisco_erspan_utc_usec;

static int hf_cisco_erspan_utcoffset;

static int hf_cisco_erspan_version;

static int ett_marker;

static int

dissect_marker(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

  proto_tree    *marker_tree;

  proto_item    *ti;

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "CISCO ERSPAN3 MARKER");

  if (tree) {

    /* Skip the proprietary CISCO header - no docs have been released for this */

    uint32_t offset = 20;

    ti = proto_tree_add_item(tree, proto_marker, tvb, 0, -1, ENC_NA);

    marker_tree = proto_item_add_subtree(ti, ett_marker);

    proto_tree_add_item(marker_tree, hf_cisco_erspan_prop_header, tvb, 0, 20, ENC_NA);

    proto_tree_add_item(marker_tree, hf_cisco_erspan_info, tvb, offset, 2, ENC_LITTLE_ENDIAN);

    offset += 2;

    proto_tree_add_item(marker_tree, hf_cisco_erspan_version, tvb, offset, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(marker_tree, hf_cisco_erspan_type, tvb, offset, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(marker_tree, hf_cisco_erspan_ssid, tvb, offset, 2, ENC_BIG_ENDIAN);

    offset += 2;

    proto_tree_add_item(marker_tree, hf_cisco_erspan_granularity, tvb, offset, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(marker_tree, hf_cisco_erspan_utcoffset, tvb, offset, 2, ENC_BIG_ENDIAN);

    offset+= 2;

    /* TODO: is this field really 6 bytes?? */

    proto_tree_add_item(marker_tree, hf_cisco_erspan_timestamp, tvb, offset, 8, ENC_BIG_ENDIAN);

    offset+=8;

    proto_tree_add_item(marker_tree, hf_cisco_erspan_utc_sec, tvb, offset, 4, ENC_BIG_ENDIAN);

    offset+=4;

    proto_tree_add_item(marker_tree, hf_cisco_erspan_utc_usec, tvb, offset, 4, ENC_BIG_ENDIAN);

    offset+=4;

    proto_tree_add_item(marker_tree, hf_cisco_erspan_sequence_number, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset+=4;

    proto_tree_add_item(marker_tree, hf_cisco_erspan_reserved, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset+=4;

    proto_tree_add_item(marker_tree, hf_cisco_erspan_tail, tvb, offset, 8, ENC_BIG_ENDIAN);

  }

  return tvb_captured_length(tvb);

}

void

proto_register_erspan_marker(void)

{

  static hf_register_info hf[] = {

    { &hf_cisco_erspan_prop_header,

      { "Proprietary CISCO Header", "erspan-marker.prop_header",

        FT_BYTES, BASE_NONE, NULL, 0x0,

        NULL, HFILL }

    },

    { &hf_cisco_erspan_info,

      { "Header", "erspan-marker.header",

        FT_BOOLEAN, BASE_NONE, NULL, 0x0,

        NULL, HFILL }

    },

    { &hf_cisco_erspan_version,

      { "Version", "erspan-marker.version",

        FT_UINT16, BASE_DEC, NULL, 0x0f00,

        NULL, HFILL }

    },

    { &hf_cisco_erspan_type,

      { "Type", "erspan-marker.type",

        FT_UINT16, BASE_DEC, NULL, 0xf000,

        NULL, HFILL }

    },

    { &hf_cisco_erspan_ssid,

      { "SSID", "erspan-marker.ssid",

        FT_UINT16, BASE_DEC, NULL, 0x00ff,

        NULL, HFILL }

    },

    { &hf_cisco_erspan_granularity,

      { "Granularity", "erspan-marker.granularity",

        FT_UINT16, BASE_DEC, NULL, 0xff00,

        NULL, HFILL }

    },

    { &hf_cisco_erspan_utcoffset,

      { "UTC Offset", "erspan-marker.utc_offset",

        FT_UINT16, BASE_DEC, NULL, 0x00ff,

        NULL, HFILL }

    },

    /* Timestamp is actually a 48-bit value, packed across 2 32-bit integers

     * Timestamp_hi : 0000 ffff (high 16-bits)

     * Timestamp_lo : ffff ffff (low 32-bits) */

    { &hf_cisco_erspan_timestamp,

      { "ASIC 48-bit Timestamp", "erspan-marker.timestamp",

        FT_UINT48, BASE_DEC, NULL, 0xffffffffffff,

        NULL, HFILL }

    },

    /* Comparison between the actual packet arrival time and this field

     * indicated that the Ethernet packet's arrival time was behind

     * the below field value by the value of the  UTC offset

     * (37 seconds as of Nov 2021) */

    { &hf_cisco_erspan_utc_sec,

      { "UTC Seconds", "erspan-marker.utc_sec",

        FT_UINT32, BASE_DEC, NULL, 0x0,

        NULL, HFILL }

    },

    { &hf_cisco_erspan_utc_usec,

      { "UTC Microseconds", "erspan-marker.utc_usec",

        FT_UINT32, BASE_DEC, NULL, 0x0,

        NULL, HFILL }

    },

    { &hf_cisco_erspan_sequence_number,

      { "Sequence Number", "erspan-marker.sequence_number",

        FT_UINT32, BASE_DEC, NULL, 0x0,

        NULL, HFILL }

    },

    { &hf_cisco_erspan_reserved,

      { "Reserved", "erspan-marker.reserved",

        FT_UINT32, BASE_HEX, NULL, 0x0,

        NULL, HFILL }

    },

    /* The 32-bit signature is expected to be 0xA5A5A5A5,

     * and while the Cisco documentation does not mention packing details,

     * it does mention padding values to enforce alignment */

    { &hf_cisco_erspan_tail,

      { "TAIL", "erspan-marker.tail",

        FT_UINT64, BASE_HEX, NULL, 0x00000000ffffffff,

        NULL, HFILL }

    },

  };

  static int *ett[] = {

    &ett_marker,

  };

  proto_marker = proto_register_protocol("CISCO ERSPAN3 Marker Packet", "CISCO3 ERSPAN MARKER", "erspan-marker");

  proto_register_field_array(proto_marker, hf, array_length(hf));

  proto_register_subtree_array(ett, array_length(ett));

  marker_handle = register_dissector("erspan-marker", dissect_marker, proto_marker);

}

void

proto_reg_handoff_erspan_marker(void)

{

  dissector_add_for_decode_as_with_preference("udp.port", marker_handle);

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * Local Variables:

 * c-basic-offset: 2

 * tab-width: 8

 * indent-tabs-mode: nil

 * End:

 *

 * ex: set shiftwidth=2 tabstop=8 expandtab:

 * :indentSize=2:tabSize=8:noTabs=true:

 */