/* packet-avsp.c

 * Arista Vendor Specific ethertype Protocol (AVSP)

 *

 * Copyright (c) 2018-2022 by Arista Networks

 * Author: Nikhil AP <nikhilap@arista.com>

 * Author: PMcL <peterm@arista.com>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1999 Gerald Combs

 *

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

 */

 /* Arista Vendor-Specific EtherType Protocol Identifier

  *

  * Arista applied for, and received the assignment of, a vendor-specific EtherType Protocol Identifier in May of 2016. Details below:

  *

  * Ethertype number is: D28B

  * Issue date is: May 12, 2016

  *

  * Arista Subtype 0x0001 is a Timestamp L2 Header

  * Arista Subtype 0xCAFE is a TGen L2 header

  *

  * The timestamp L2 header consists of the following fields:

  *

  * Arista Vendor Specific Protocol EtherType (0xD28B)

  *     Two-byte protocol subtype of 0x0001

  *     Two-byte protocol version: 0x0010 for 64-bit timestamp and 0x0020 for 48-bit timestamp

  *     UTC timestamp value in IEEE 1588 time of day format (either 64-bit or 48-bit) with the lower 32-bits representing nanoseconds and upper bits representing seconds.

  *

  * The TGen L2 header consists of the following fields:

  *

  * Arista Vendor Specific Protocol EtherType (0xD28B)

  *     Two-byte protocol subtype of 0xCAFE

  *     Two-byte protocol version: 0x0001

  */

#include "config.h"

#include <epan/packet.h>

#include <epan/exceptions.h>

#include <epan/etypes.h>

#include <epan/expert.h>

#include <epan/address.h>

#include <wsutil/str_util.h>

#include "packet-eth.h"

#define ARISTA_SUBTYPE_TIMESTAMP 0x0001

#define ARISTA_TIMESTAMP_64_TAI 0x0010

#define ARISTA_TIMESTAMP_64_UTC 0x0110

#define ARISTA_TIMESTAMP_48_TAI 0x0020

#define ARISTA_TIMESTAMP_48_UTC 0x0120

#define ARISTA_TIMESTAMP_64_TAI_J2 0x0011

#define ARISTA_TIMESTAMP_64_UTC_J2 0x0111

#define ARISTA_TIMESTAMP_48_TAI_J2 0x0021

#define ARISTA_TIMESTAMP_48_UTC_J2 0x0121

#define ARISTA_SUBTYPE_GREENTAP 0x0003

#define ARISTA_GREENTAP_48_TAI 0x0020

#define ARISTA_GREENTAP_48_UTC 0x0120

#define ARISTA_SUBTYPE_GREENT 0x0004

#define ARISTA_GREENT_VER_1 0x0001

#define ARISTA_SUBTYPE_DZGRE_A  0x0007

#define ARISTA_DZGRE_A_VER_1 0x0001

#define ARISTA_SUBTYPE_DZGRE_B  0x0008

#define ARISTA_DZGRE_B_VER_1 0x0001

#define ARISTA_SUBTYPE_DZGRE_TS  0x0009

#define ARISTA_DZGRE_TS_64_TAI 0x0011

#define ARISTA_DZGRE_TS_64_UTC 0x0111

#define ARISTA_SUBTYPE_TGEN 0xCAFE

#define ARISTA_TGEN_VER_1 0x0001

#define ROUNDUP(x, y) ((((x) + ((y) - 1)) / (y)) * (y))

void proto_reg_handoff_avsp(void);

void proto_register_avsp(void);

static dissector_handle_t avsp_handle;

static int proto_avsp;

/* sub trees */

static int ett_avsp;

static int ett_avsp_ts_48;

static int ett_avsp_ts_64;

static int ett_avsp_dzgre_a_hdr;

static int ett_avsp_dzgre_b_hdr;

static int ett_avsp_dzgre_ts_hdr;

static int ett_avsp_dzgre_ts_tai;

static int ett_avsp_dzgre_ts_utc;

static int ett_avsp_greent_hdr;

static int ett_avsp_greent_sample_hdr;

static int ett_avsp_greent_sample_data;

static int ett_avsp_tgen_hdr;

static int ett_avsp_tgen_hdr_ctrl;

static int ett_avsp_tgen_payload;

/* AVSP Timestamp subtype header fields */

static int hf_avsp_subtype;

static int hf_avsp_ts_version;

static int hf_avsp_ts_64_tai;

static int hf_avsp_ts_64_utc;

static int hf_avsp_ts_64_sec;

static int hf_avsp_ts_64_ns;

static int hf_avsp_ts_48_tai;

static int hf_avsp_ts_48_utc;

static int hf_avsp_ts_48_sec;

static int hf_avsp_ts_48_ns;

static int hf_avsp_etype;

static int hf_avsp_trailer;

/*

  GREENTAP Timestamping format

   0.............7...............15..............23..............31

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  |   Protocol Subtype = 0x0003   |      Protocol Version         |

  +---------------+---------------+---------------+---------------+

  |          Session ID           |      Timestamp (seconds)      |

  +---------------+---------------+---------------+---------------+

  |0 0|                Timestamp (nanoseconds)                    |

  +---------------+---------------+---------------+---------------+

*/

/* AVSP GREENTAP subtype header fields */

static int hf_avsp_greentap_version;

static int hf_avsp_greentap_tai;

static int hf_avsp_greentap_utc;

static int hf_avsp_greentap_sec;

static int hf_avsp_greentap_ns;

/*

  GREENT subtype format

   0.............7...............15..............23..............31

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  |   Protocol Subtype = 0x0004   |      Protocol Version         |

  +---------------+---------------+---------------+---------------+

  |         Session ID            |     Flags     | Sample Count  |

  +---------------+---------------+---------------+---------------+

  Each sample has a header of the format:

   0.............7...............15..............23..............31

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  |           Length              |     IEEE 1588 TS (seconds)    |

  +---------------+---------------+---------------+---------------+

  |                   IEEE 1588 TS (nanoseconds)                  |

  +---------------+---------------+---------------+---------------+

  |                   Ingress Port (SNMP ifIndex)                 |

  +---------------+---------------+---------------+---------------+

  |                   Egress Port (SNMP ifIndex)                  |

  +---------------+---------------+---------------+---------------+

  |  Sample Rate (multiplier 1K)  |        Payload Checksum       |

  +---------------+---------------+---------------+---------------+

  |               Sample (padded to 4 byte boundary)              |

  +---------------+---------------+---------------+---------------+

*/

/* AVSP GREENT subtype header fields */

static int hf_avsp_greent_hdr;

static int hf_avsp_greent_version;

static int hf_avsp_greent_session;

static int hf_avsp_greent_flags;

static int hf_avsp_greent_sample_count;

/* GREENT sample header fields */

static int hf_avsp_greent_sample_hdr;

static int hf_avsp_greent_sample_len;

static int hf_avsp_greent_sample_sec;

static int hf_avsp_greent_sample_ns;

static int hf_avsp_greent_sample_ingress;

static int hf_avsp_greent_sample_egress;

static int hf_avsp_greent_sample_rate;

static int hf_avsp_greent_sample_sum;

static int hf_avsp_greent_sample_data;

/*

  DzGRE Plan A subtype format

   0.............7...............15..............23..............31

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  |   Protocol Subtype = 0x0007   |      Protocol Version         |

  +---------------+---------------+---------------+---------------+

  |          Switch ID            |           Port ID             |

  +---------------+---------------+---------------+---------------+

  |          Policy ID            |           Reserved            |

  +---------------+---------------+---------------+---------------+

  DzGRE Plan B subtype format

   0.............7...............15..............23..............31

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  |   Protocol Subtype = 0x0008   |      Protocol Version         |

  +---------------+---------------+---------------+---------------+

  |0 0 0 0|      Port ID          |0 0 0 0|     Policy ID         |

  +---------------+---------------+---------------+---------------+

  DzGRE with timestamping

   0.............7...............15..............23..............31

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  |   Protocol Subtype = 0x0009   |      Protocol Version         |

  +---------------+---------------+---------------+---------------+

  |          Switch ID            |           Port ID             |

  +---------------+---------------+---------------+---------------+

  |          Policy ID            |           Reserved            |

  +---------------+---------------+---------------+---------------+

  |                  UTC Timestamp (seconds)                      |

  +---------------+---------------+---------------+---------------+

  |                  UTC Timestamp (nanoseconds)                  |

  +---------------+---------------+---------------+---------------+

*/

/* AVSP DzGRE header fields */

static int hf_avsp_dzgre_a_hdr;

static int hf_avsp_dzgre_a_version;

static int hf_avsp_dzgre_a_switch;

static int hf_avsp_dzgre_a_port;

static int hf_avsp_dzgre_a_policy;

static int hf_avsp_dzgre_a_reserved;

static int hf_avsp_dzgre_b_hdr;

static int hf_avsp_dzgre_b_version;

static int hf_avsp_dzgre_b_port;

static int hf_avsp_dzgre_b_policy;

static int hf_avsp_dzgre_ts_hdr;

static int hf_avsp_dzgre_ts_version;

static int hf_avsp_dzgre_ts_switch;

static int hf_avsp_dzgre_ts_port;

static int hf_avsp_dzgre_ts_policy;

static int hf_avsp_dzgre_ts_reserved;

static int hf_avsp_dzgre_ts_tai;

static int hf_avsp_dzgre_ts_utc;

static int hf_avsp_dzgre_ts_sec;

static int hf_avsp_dzgre_ts_ns;

/*

  TGen subtype format

   0.............7...............15..............23..............31

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  |      Ethertype = 0xD28B       |   Protocol Subtype = 0xCAFE   |

  +---------------+---------------+---------------+---------------+

  |   Protocol Version = 0x0001   |      TGen Control Word        |

  +---------------+---------------+---------------+---------------+

  |     TGen Sequence Number      |      TGen Payload Length      |

  +---------------+---------------+---------------+---------------+

  |                        TGen Data Payload                      |

  +---------------+---------------+---------------+---------------+

  |                              ...                              |

  +---------------+---------------+---------------+---------------+

  |                        TGen Data Payload                      |

  +---------------+---------------+---------------+---------------+

*/

/* AVSP TGen subtype header fields */

static int hf_avsp_tgen_version;

static int hf_avsp_tgen_hdr;

static int hf_avsp_tgen_hdr_ctrl;

static int hf_avsp_tgen_hdr_ctrl_fcs_inverted;

static int hf_avsp_tgen_hdr_ctrl_reserved;

static int hf_avsp_tgen_hdr_seq_num;

static int hf_avsp_tgen_hdr_payload_len;

static int hf_avsp_tgen_payload;

static int hf_avsp_tgen_payload_data;

static int* const avsp_tgen_ctrl[] = {

    &hf_avsp_tgen_hdr_ctrl_fcs_inverted,

    &hf_avsp_tgen_hdr_ctrl_reserved,

    NULL

};

static dissector_handle_t ethertype_handle;

static const value_string arista_subtypes[] = {

    {ARISTA_SUBTYPE_TIMESTAMP, "timestamp"},

    {ARISTA_SUBTYPE_GREENTAP, "GRE TAP"},

    {ARISTA_SUBTYPE_GREENT, "Postcard"},

    {ARISTA_SUBTYPE_DZGRE_A, "DzGRE (plan A)"},

    {ARISTA_SUBTYPE_DZGRE_B, "DzGRE (plan B)"},

    {ARISTA_SUBTYPE_DZGRE_TS, "DzGRE (timestamped)"},

    {ARISTA_SUBTYPE_TGEN, "TGen"},

    {0, NULL}

};

static const value_string ts_versions[] = {

    {ARISTA_TIMESTAMP_64_TAI, "010"},

    {ARISTA_TIMESTAMP_64_UTC, "110"},

    {ARISTA_TIMESTAMP_48_TAI, "020"},

    {ARISTA_TIMESTAMP_48_UTC, "120"},

    {ARISTA_TIMESTAMP_64_TAI_J2, "011"},

    {ARISTA_TIMESTAMP_64_UTC_J2, "111"},

    {ARISTA_TIMESTAMP_48_TAI_J2, "021"},

    {ARISTA_TIMESTAMP_48_UTC_J2, "121"},

    {0, NULL}

};

static const value_string greentap_versions[] = {

    {ARISTA_GREENTAP_48_TAI, "48bit TAI"},

    {ARISTA_GREENTAP_48_UTC, "48bit UTC"},

    {0, NULL}

};

static const value_string greent_versions[] = {

    {ARISTA_GREENT_VER_1, "1"},

    {0, NULL}

};

static const value_string dzgre_a_versions[] = {

    {ARISTA_DZGRE_A_VER_1, "1"},

    {0, NULL}

};

static const value_string dzgre_b_versions[] = {

    {ARISTA_DZGRE_A_VER_1, "1"},

    {0, NULL}

};

static const value_string dzgre_ts_versions[] = {

    {ARISTA_DZGRE_TS_64_TAI, "64bit TAI"},

    {ARISTA_DZGRE_TS_64_UTC, "64bit UTC"},

    {0, NULL}

};

static const value_string tgen_versions[] = {

    {ARISTA_TGEN_VER_1, "1"},

    {0, NULL}

};

static expert_field ei_avsp_unknown_subtype;

static expert_field ei_avsp_ts_unknown_version;

static expert_field ei_avsp_greentap_unknown_version;

static expert_field ei_avsp_greent_unknown_version;

static expert_field ei_avsp_dzgre_a_unknown_version;

static expert_field ei_avsp_dzgre_b_unknown_version;

static expert_field ei_avsp_dzgre_ts_unknown_version;

static expert_field ei_avsp_tgen_unknown_version;

static int

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

{

    volatile int offset = 0;

    uint32_t version, subtype, tgen_payload_len = 0;

    uint64_t tgen_ctrl;

    uint32_t tgen_seq_num, sample_len, count, u32;

    volatile uint32_t i; // potentially held across vfork

    const char* str;

    uint16_t encap_proto;

    ethertype_data_t ethertype_data;

    tvbuff_t* volatile tgen_payload_tvb = NULL;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "AVSP");

    col_clear(pinfo->cinfo, COL_INFO);

    proto_item* avsp_ti, * ti;

    proto_tree* avsp_tree, * avsp_48_tree = NULL, * avsp_64_tree = NULL,

        * avsp_tgen_hdr = NULL, * avsp_tgen_payload = NULL,

        * avsp_dzgre_hdr = NULL, * avsp_greent_hdr = NULL,

        * avsp_greent_sample_hdr = NULL, *header_tree = NULL;

    /* Adding Items and Values to the Protocol Tree */

    avsp_ti = proto_tree_add_item(tree, proto_avsp, tvb, 0, -1,

        ENC_NA);

    avsp_tree = proto_item_add_subtree(avsp_ti, ett_avsp);

    /* add the subtype to avsp */

    proto_tree_add_item_ret_uint(avsp_tree, hf_avsp_subtype, tvb,

        offset, 2, ENC_BIG_ENDIAN, &subtype);

    str = try_val_to_str(subtype, arista_subtypes);

    if (str) {

        proto_item_append_text(avsp_ti, ", Subtype: %s", str);

    }

    offset += 2;

    /* Based on the subtype, add the version and further custom protocol fields */

    switch (subtype) {

    case ARISTA_SUBTYPE_TIMESTAMP:

        proto_tree_add_item_ret_uint(avsp_tree, hf_avsp_ts_version, tvb, offset,

            2, ENC_BIG_ENDIAN, &version);

        str = try_val_to_str(version, ts_versions);

        if (str) {

            proto_item_append_text(avsp_ti, ", Version: %s", str);

        }

        offset += 2;

        switch (version) {

        case ARISTA_TIMESTAMP_64_TAI:

        case ARISTA_TIMESTAMP_64_TAI_J2:

            ti = proto_tree_add_item(avsp_tree, hf_avsp_ts_64_tai, tvb, 0, -1,

                ENC_NA);

            avsp_64_tree = proto_item_add_subtree(ti, ett_avsp);

            col_set_str(pinfo->cinfo, COL_INFO, "64bit TAI timestamp");

            proto_tree_add_item(avsp_64_tree, hf_avsp_ts_64_sec, tvb, offset,

                4, ENC_BIG_ENDIAN);

            offset += 4;

            proto_tree_add_item(avsp_64_tree, hf_avsp_ts_64_ns, tvb, offset,

                4, ENC_BIG_ENDIAN);

            offset += 4;

            break;

        case ARISTA_TIMESTAMP_64_UTC:

        case ARISTA_TIMESTAMP_64_UTC_J2:

            ti = proto_tree_add_item(avsp_tree, hf_avsp_ts_64_utc, tvb, 0, -1,

                ENC_NA);

            avsp_64_tree = proto_item_add_subtree(ti, ett_avsp);

            col_set_str(pinfo->cinfo, COL_INFO, "64bit UTC timestamp");

            proto_tree_add_item(avsp_64_tree, hf_avsp_ts_64_sec, tvb, offset,

                4, ENC_BIG_ENDIAN);

            offset += 4;

            proto_tree_add_item(avsp_64_tree, hf_avsp_ts_64_ns, tvb, offset,

                4, ENC_BIG_ENDIAN);

            offset += 4;

            break;

        case ARISTA_TIMESTAMP_48_TAI:

        case ARISTA_TIMESTAMP_48_TAI_J2:

            ti = proto_tree_add_item(avsp_tree, hf_avsp_ts_48_tai, tvb, 0, -1,

                ENC_NA);

            avsp_48_tree = proto_item_add_subtree(ti, ett_avsp);

            col_set_str(pinfo->cinfo, COL_INFO, "48bit TAI timestamp");

            proto_tree_add_item(avsp_48_tree, hf_avsp_ts_48_sec, tvb, offset,

                2, ENC_BIG_ENDIAN);

            offset += 2;

            proto_tree_add_item(avsp_48_tree, hf_avsp_ts_48_ns, tvb, offset,

                4, ENC_BIG_ENDIAN);

            offset += 4;

            break;

        case ARISTA_TIMESTAMP_48_UTC:

        case ARISTA_TIMESTAMP_48_UTC_J2:

            ti = proto_tree_add_item(avsp_tree, hf_avsp_ts_48_utc, tvb, 0, -1,

                ENC_NA);

            avsp_48_tree = proto_item_add_subtree(ti, ett_avsp);

            col_set_str(pinfo->cinfo, COL_INFO, "48bit UTC timestamp");

            proto_tree_add_item(avsp_48_tree, hf_avsp_ts_48_sec, tvb, offset,

                2, ENC_BIG_ENDIAN);

            offset += 2;

            proto_tree_add_item(avsp_48_tree, hf_avsp_ts_48_ns, tvb, offset,

                4, ENC_BIG_ENDIAN);

            offset += 4;

            break;

        default:

            expert_add_info_format(pinfo, avsp_ti, &ei_avsp_ts_unknown_version,

                "Unknown timestamp version: 0x%0x", version);

            return tvb_captured_length(tvb);

        }

        encap_proto = tvb_get_ntohs(tvb, offset);

        proto_tree_add_uint(avsp_tree, hf_avsp_etype, tvb, offset, 2, encap_proto);

        offset += 2;

        ethertype_data.etype = encap_proto;

        ethertype_data.payload_offset = offset;

        ethertype_data.fh_tree = avsp_tree;

        ethertype_data.trailer_id = hf_avsp_trailer;

        ethertype_data.fcs_len = 0;

        call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, &ethertype_data);

        break;

    case ARISTA_SUBTYPE_GREENTAP:

        proto_tree_add_item_ret_uint(avsp_tree, hf_avsp_greentap_version, tvb,

            offset, 2, ENC_BIG_ENDIAN, &version);

        str = try_val_to_str(version, greentap_versions);

        if (str) {

            proto_item_append_text(avsp_ti, ", Version: %s", str);

        }

        offset += 2;

        switch (version) {

        case ARISTA_GREENTAP_48_TAI:

            ti = proto_tree_add_item(avsp_tree, hf_avsp_greentap_tai, tvb,

                0, -1, ENC_NA);

            avsp_48_tree = proto_item_add_subtree(ti, ett_avsp);

            col_set_str(pinfo->cinfo, COL_INFO, "48bit TAI timestamp");

            proto_tree_add_item(avsp_48_tree, hf_avsp_greentap_sec,

                tvb, offset, 2, ENC_BIG_ENDIAN);

            offset += 2;

            proto_tree_add_item(avsp_48_tree, hf_avsp_greentap_ns,

                tvb, offset, 4, ENC_BIG_ENDIAN);

            offset += 4;

            break;

        case ARISTA_GREENTAP_48_UTC:

            ti = proto_tree_add_item(avsp_tree, hf_avsp_greentap_utc, tvb,

                0, -1, ENC_NA);

            avsp_48_tree = proto_item_add_subtree(ti, ett_avsp);

            col_set_str(pinfo->cinfo, COL_INFO, "48bit TAI timestamp");

            proto_tree_add_item(avsp_48_tree, hf_avsp_greentap_sec,

                tvb, offset, 2, ENC_BIG_ENDIAN);

            offset += 2;

            proto_tree_add_item(avsp_48_tree, hf_avsp_greentap_ns,

                tvb, offset, 4, ENC_BIG_ENDIAN);

            offset += 4;

            break;

        default:

            expert_add_info_format(pinfo, avsp_ti,

                &ei_avsp_greentap_unknown_version,

                "Unknown GRE TAP version: 0x%0x", version);

            return tvb_captured_length(tvb);

        }

        encap_proto = tvb_get_ntohs(tvb, offset);

        proto_tree_add_uint(avsp_tree, hf_avsp_etype, tvb, offset, 2,

                encap_proto);

        offset += 2;

        ethertype_data.etype = encap_proto;

        ethertype_data.payload_offset = offset;

        ethertype_data.fh_tree = avsp_tree;

        ethertype_data.trailer_id = hf_avsp_trailer;

        ethertype_data.fcs_len = 0;

        call_dissector_with_data(ethertype_handle, tvb, pinfo, tree,

                &ethertype_data);

        break;

    case ARISTA_SUBTYPE_GREENT:

        proto_tree_add_item_ret_uint(avsp_tree, hf_avsp_greent_version, tvb,

            offset, 2, ENC_BIG_ENDIAN, &version);

        str = try_val_to_str(version, greent_versions);

        if (str) {

            proto_item_append_text(avsp_ti, ", Version: %s", str);

        }

        offset += 2;

        switch (version) {

        case ARISTA_GREENT_VER_1:

            col_set_str(pinfo->cinfo, COL_INFO, "Arista Postcard Telemetry");

            ti = proto_tree_add_item(avsp_tree, hf_avsp_greent_hdr, tvb, 0,

                -1, ENC_NA);

            avsp_greent_hdr = proto_item_add_subtree(ti, ett_avsp_greent_hdr);

            /* Session ID */

            proto_tree_add_item_ret_uint(avsp_greent_hdr,

                    hf_avsp_greent_session, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Session ID: %u", u32);

            offset += 2;

            /* Flags */

            proto_tree_add_item_ret_uint(avsp_greent_hdr,

                    hf_avsp_greent_flags, tvb, offset, 1, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Flags: 0x%02x", u32);

            offset += 1;

            /* Sample Count */

            proto_tree_add_item_ret_uint(avsp_greent_hdr,

                    hf_avsp_greent_sample_count, tvb, offset, 1, ENC_BIG_ENDIAN,

                    &count);

            proto_item_append_text(ti, ", Count: %u", count);

            offset += 1;

            for (i = 0; i < count; i++) {

                ti = proto_tree_add_item(avsp_greent_hdr,

                        hf_avsp_greent_sample_hdr, tvb, 0, -1, ENC_NA);

                avsp_greent_sample_hdr = proto_item_add_subtree(ti,

                        ett_avsp_greent_sample_hdr);

                /* Length */

                proto_tree_add_item_ret_uint(avsp_greent_sample_hdr,

                        hf_avsp_greent_sample_len, tvb, offset, 2,

                        ENC_BIG_ENDIAN, &sample_len);

                proto_item_append_text(ti, ", Length: %u", sample_len);

                offset += 2;

                /* Seconds */

                proto_tree_add_item_ret_uint(avsp_greent_sample_hdr,

                        hf_avsp_greent_sample_sec, tvb, offset, 2,

                        ENC_BIG_ENDIAN, &u32);

                proto_item_append_text(ti, ", Seconds: %u", u32);

                offset += 2;

                /* Nanoseconds */

                proto_tree_add_item_ret_uint(avsp_greent_sample_hdr,

                        hf_avsp_greent_sample_ns, tvb, offset, 4,

                        ENC_BIG_ENDIAN, &u32);

                proto_item_append_text(ti, ", Nanoseconds: %u", u32);

                offset += 4;

                /* Ingress */

                proto_tree_add_item_ret_uint(avsp_greent_sample_hdr,

                        hf_avsp_greent_sample_ingress, tvb, offset, 4,

                        ENC_BIG_ENDIAN, &u32);

                proto_item_append_text(ti, ", Ingress: %u", u32);

                offset += 4;

                /* Egress */

                proto_tree_add_item_ret_uint(avsp_greent_sample_hdr,

                        hf_avsp_greent_sample_egress, tvb, offset, 4,

                        ENC_BIG_ENDIAN, &u32);

                proto_item_append_text(ti, ", Egress: %u", u32);

                offset += 4;

                /* Sample Rate */

                proto_tree_add_item_ret_uint(avsp_greent_sample_hdr,

                        hf_avsp_greent_sample_rate, tvb, offset, 2,

                        ENC_BIG_ENDIAN, &u32);

                proto_item_append_text(ti, ", Rate: %u", u32);

                offset += 2;

                /* Checksum */

                proto_tree_add_item_ret_uint(avsp_greent_sample_hdr,

                        hf_avsp_greent_sample_sum, tvb, offset, 2,

                        ENC_BIG_ENDIAN, &u32);

                proto_item_append_text(ti, ", Checksum: 0x%04x", u32);

                offset += 2;

                /* Sample Data */

                ti = proto_tree_add_item(avsp_greent_sample_hdr,

                        hf_avsp_greent_sample_data, tvb, offset, sample_len,

                        ENC_NA);

                header_tree = proto_item_add_subtree(ti,

                        ett_avsp_greent_sample_data);

                /*

                 * We call the ethernet dissector on the sample, but since

                 * the sample is truncated it will likely generate errors.

                 * This is an attempt to isolate those errors, borrowed from

                 * sflow.

                 */

                {

                    tvbuff_t *next_tvb;

                    address save_dl_src, save_dl_dst, save_net_src,

                            save_net_dst, save_src, save_dst;

                    bool save_writable, save_in_error_pkt;

                    sample_len = ROUNDUP(sample_len, 4);

                    next_tvb = tvb_new_subset_length(tvb, offset, sample_len);

                    save_in_error_pkt = pinfo->flags.in_error_pkt;

                    pinfo->flags.in_error_pkt = true;

                    save_writable = col_get_writable(pinfo->cinfo, -1);

                    col_set_writable(pinfo->cinfo, -1, false);

                    copy_address_shallow(&save_dl_src, &pinfo->dl_src);

                    copy_address_shallow(&save_dl_dst, &pinfo->dl_dst);

                    copy_address_shallow(&save_net_src, &pinfo->net_src);

                    copy_address_shallow(&save_net_dst, &pinfo->net_dst);

                    copy_address_shallow(&save_src, &pinfo->src);

                    copy_address_shallow(&save_dst, &pinfo->dst);

                    TRY

                    {

                        // always ethernet for greent

                        ethertype_data.etype = ETHERTYPE_ETHBRIDGE;

                        ethertype_data.payload_offset = 0;

                        ethertype_data.fh_tree = header_tree;

                        ethertype_data.trailer_id = hf_avsp_trailer;

                        ethertype_data.fcs_len = 0;

                        call_dissector_with_data(ethertype_handle, next_tvb,

                                pinfo, header_tree, &ethertype_data);

                    }

                    CATCH_BOUNDS_ERRORS {

                    }

                    ENDTRY;

                    col_set_writable(pinfo->cinfo, -1, save_writable);

                    pinfo->flags.in_error_pkt = save_in_error_pkt;

                    copy_address_shallow(&pinfo->dl_src, &save_dl_src);

                    copy_address_shallow(&pinfo->dl_dst, &save_dl_dst);

                    copy_address_shallow(&pinfo->net_src, &save_net_src);

                    copy_address_shallow(&pinfo->net_dst, &save_net_dst);

                    copy_address_shallow(&pinfo->src, &save_src);

                    copy_address_shallow(&pinfo->dst, &save_dst);

                }

            }

            break;

        default:

            expert_add_info_format(pinfo, avsp_ti,

                    &ei_avsp_greent_unknown_version,

                "Unknown version: 0x%0x", version);

            return tvb_captured_length(tvb);

        }

        break;

    case ARISTA_SUBTYPE_DZGRE_A:

        proto_tree_add_item_ret_uint(avsp_tree, hf_avsp_dzgre_a_version, tvb,

            offset, 2, ENC_BIG_ENDIAN, &version);

        str = try_val_to_str(version, dzgre_a_versions);

        if (str) {

            proto_item_append_text(avsp_ti, ", Version: %s", str);

        }

        offset += 2;

        switch (version) {

        case ARISTA_DZGRE_A_VER_1:

            col_set_str(pinfo->cinfo, COL_INFO, "Arista DzGRE(A) Frame");

            ti = proto_tree_add_item(avsp_tree, hf_avsp_dzgre_a_hdr, tvb,

                    0, -1, ENC_NA);

            avsp_dzgre_hdr = proto_item_add_subtree(ti, ett_avsp_dzgre_a_hdr);

            /* Switch ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_a_switch, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Switch ID: %u", u32);

            offset += 2;

            /* Port ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_a_port, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Port ID: %u", u32);

            offset += 2;

            /* Policy ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_a_policy, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Policy ID: %u", u32);

            offset += 2;

            /* Reserved */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_a_reserved, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            offset += 2;

            break;

        default:

            expert_add_info_format(pinfo, avsp_ti,

                    &ei_avsp_dzgre_a_unknown_version,

                "Unknown version: 0x%0x", version);

            return tvb_captured_length(tvb);

        }

        ethertype_data.etype = ETHERTYPE_ETHBRIDGE; // always ethernet

        ethertype_data.payload_offset = offset;

        ethertype_data.fh_tree = avsp_tree;

        ethertype_data.trailer_id = hf_avsp_trailer;

        ethertype_data.fcs_len = 0;

        call_dissector_with_data(ethertype_handle, tvb, pinfo, tree,

                &ethertype_data);

        break;

    case ARISTA_SUBTYPE_DZGRE_B:

        proto_tree_add_item_ret_uint(avsp_tree, hf_avsp_dzgre_b_version, tvb,

            offset, 2, ENC_BIG_ENDIAN, &version);

        str = try_val_to_str(version, dzgre_b_versions);

        if (str) {

            proto_item_append_text(avsp_ti, ", Version: %s", str);

        }

        offset += 2;

        switch (version) {

        case ARISTA_DZGRE_B_VER_1:

            col_set_str(pinfo->cinfo, COL_INFO, "Arista DzGRE(B) Frame");

            ti = proto_tree_add_item(avsp_tree, hf_avsp_dzgre_b_hdr, tvb,

                    0, -1, ENC_NA);

            avsp_dzgre_hdr = proto_item_add_subtree(ti, ett_avsp_dzgre_b_hdr);

            /* Port ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_b_port, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Port ID: %u", u32);

            offset += 2;

            /* Policy ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_b_policy, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Policy ID: %u", u32);

            offset += 2;

            break;

        default:

            expert_add_info_format(pinfo, avsp_ti,

                    &ei_avsp_dzgre_b_unknown_version,

                "Unknown version: 0x%0x", version);

            return tvb_captured_length(tvb);

        }

        ethertype_data.etype = ETHERTYPE_ETHBRIDGE; // always ethernet

        ethertype_data.payload_offset = offset;

        ethertype_data.fh_tree = avsp_tree;

        ethertype_data.trailer_id = hf_avsp_trailer;

        ethertype_data.fcs_len = 0;

        call_dissector_with_data(ethertype_handle, tvb, pinfo, tree,

                &ethertype_data);

        break;

    case ARISTA_SUBTYPE_DZGRE_TS:

        proto_tree_add_item_ret_uint(avsp_tree, hf_avsp_dzgre_ts_version, tvb,

            offset, 2, ENC_BIG_ENDIAN, &version);

        str = try_val_to_str(version, dzgre_ts_versions);

        if (str) {

            proto_item_append_text(avsp_ti, ", Version: %s", str);

        }

        offset += 2;

        switch (version) {

        case ARISTA_DZGRE_TS_64_TAI:

            col_set_str(pinfo->cinfo, COL_INFO, "Arista DzGRE(A) Frame");

            ti = proto_tree_add_item(avsp_tree, hf_avsp_dzgre_ts_hdr, tvb,

                    0, -1, ENC_NA);

            avsp_dzgre_hdr = proto_item_add_subtree(ti, ett_avsp_dzgre_ts_hdr);

            /* Switch ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_ts_switch, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Switch ID: %u", u32);

            offset += 2;

            /* Port ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_ts_port, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Port ID: %u", u32);

            offset += 2;

            /* Policy ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_ts_policy, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Policy ID: %u", u32);

            offset += 2;

            /* Reserved */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_ts_reserved, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            offset += 2;

            /* Timestamp */

            ti = proto_tree_add_item(avsp_dzgre_hdr,

                    hf_avsp_dzgre_ts_tai, tvb, 0, -1, ENC_NA);

            avsp_64_tree = proto_item_add_subtree(ti,

                    ett_avsp_dzgre_ts_tai);

            col_set_str(pinfo->cinfo, COL_INFO, "64bit TAI timestamp");

            proto_tree_add_item(avsp_64_tree, hf_avsp_dzgre_ts_sec,

                tvb, offset, 4, ENC_BIG_ENDIAN);

            offset += 4;

            proto_tree_add_item(avsp_64_tree, hf_avsp_dzgre_ts_ns,

                tvb, offset, 4, ENC_BIG_ENDIAN);

            offset += 4;

            break;

        case ARISTA_DZGRE_TS_64_UTC:

            col_set_str(pinfo->cinfo, COL_INFO,

                    "Arista DzGRE(timestamped) Frame");

            ti = proto_tree_add_item(avsp_tree, hf_avsp_dzgre_ts_hdr, tvb,

                    0, -1, ENC_NA);

            avsp_dzgre_hdr = proto_item_add_subtree(ti, ett_avsp_dzgre_ts_hdr);

            /* Switch ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_ts_switch, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Switch ID: 0x%u", u32);

            offset += 2;

            /* Port ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_ts_port, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Port ID: 0x%u", u32);

            offset += 2;

            /* Policy ID */

            proto_tree_add_item_ret_uint(avsp_dzgre_hdr,

                    hf_avsp_dzgre_ts_policy, tvb, offset, 2, ENC_BIG_ENDIAN,

                    &u32);

            proto_item_append_text(ti, ", Policy ID: 0x%u", u32);

            offset += 2;

            /* Reserved */

            offset += 2;

            /* Timestamp */

            ti = proto_tree_add_item(avsp_dzgre_hdr,

                    hf_avsp_dzgre_ts_utc, tvb, 0, -1, ENC_NA);

            avsp_64_tree = proto_item_add_subtree(ti,

                    ett_avsp_dzgre_ts_utc);

            col_set_str(pinfo->cinfo, COL_INFO, "64bit UTC timestamp");

            proto_tree_add_item(avsp_64_tree, hf_avsp_dzgre_ts_sec,

                tvb, offset, 4, ENC_BIG_ENDIAN);

            offset += 4;

            proto_tree_add_item(avsp_64_tree, hf_avsp_dzgre_ts_ns,

                tvb, offset, 4, ENC_BIG_ENDIAN);

            offset += 4;

            break;

        default:

            expert_add_info_format(pinfo, avsp_ti,

                    &ei_avsp_dzgre_ts_unknown_version,

                "Unknown version: 0x%0x", version);

            return tvb_captured_length(tvb);

        }

        ethertype_data.etype = ETHERTYPE_ETHBRIDGE; // always ethernet

        ethertype_data.payload_offset = offset;

        ethertype_data.fh_tree = avsp_tree;

        ethertype_data.trailer_id = hf_avsp_trailer;

        ethertype_data.fcs_len = 0;

        call_dissector_with_data(ethertype_handle, tvb, pinfo, tree,

                &ethertype_data);

        break;

    case ARISTA_SUBTYPE_TGEN:

        proto_tree_add_item_ret_uint(avsp_tree, hf_avsp_tgen_version, tvb,

            offset, 2, ENC_BIG_ENDIAN, &version);

        str = try_val_to_str(version, tgen_versions);

        if (str) {

            proto_item_append_text(avsp_ti, ", Version: %s", str);

        }

        offset += 2;

        switch (version) {

        case ARISTA_TGEN_VER_1:

            col_set_str(pinfo->cinfo, COL_INFO, "Arista TGen Frame");

            /* Get TGen Header Control Word. */

            ti = proto_tree_add_item(avsp_tree, hf_avsp_tgen_hdr, tvb, offset, 6,

                ENC_NA);

            avsp_tgen_hdr = proto_item_add_subtree(ti, ett_avsp_tgen_hdr);

            proto_tree_add_bitmask_ret_uint64(avsp_tgen_hdr, tvb, offset,

                hf_avsp_tgen_hdr_ctrl, ett_avsp_tgen_hdr_ctrl, avsp_tgen_ctrl,

                ENC_BIG_ENDIAN, &tgen_ctrl);

            proto_item_append_text(ti, ", Control Word: 0x%04" PRIx64, tgen_ctrl);

            col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "Ctrl=0x%04" PRIx64, tgen_ctrl);

            offset += 2;

            /* Get TGen Header Sequence Number*/

            proto_tree_add_item_ret_uint(avsp_tgen_hdr, hf_avsp_tgen_hdr_seq_num, tvb,

                offset, 2, ENC_BIG_ENDIAN, &tgen_seq_num);

            proto_item_append_text(ti, ", Sequence Number: %u", tgen_seq_num);

            col_append_str_uint(pinfo->cinfo, COL_INFO, "Seq", tgen_seq_num, ", ");

            offset += 2;

            /* Get TGen Header Payload Length */

            proto_tree_add_item_ret_uint(avsp_tgen_hdr,

                hf_avsp_tgen_hdr_payload_len, tvb, offset, 2, ENC_BIG_ENDIAN,

                &tgen_payload_len);

            proto_item_append_text(ti, ", Payload Length: %u", tgen_payload_len);

            col_append_str_uint(pinfo->cinfo, COL_INFO, "Len", tgen_payload_len, ", ");

            offset += 2;

            /* Try to construct a tvbuff containing only

                the data specified by the tgen_payload_len field. */