/* packet-cisco-erspan.c

 * Routines for the disassembly of Cisco's ERSPAN protocol

 *

 * Copyright 2005 Joerg Mayer (see AUTHORS file)

 * Updates for newer versions by Jason Masker <jason at masker.net>

 * Updates to support ERSPAN3 by Peter Membrey <peter@membrey.hk>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

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

 *

 * Protocol Spec:

 *   https://tools.ietf.org/html/draft-foschiano-erspan-03

 *

 * For ERSPAN packets, the "protocol type" field value in the GRE header

 * is 0x88BE (types I and II) or 0x22EB (type III).

 *

 * For 0x88BE, if the GRE header doesn't have the "sequence number present"

 * flag set, it's type I, with no ERSPAN header, otherwise it has an

 * ERSPAN header (it's supposed to be type II, but we look at the version

 * in the ERSPAN header; should we report an error if it's not version 1?).

 *

 * For 0x22EB, it always has an ERSPAN header (it's supposed to be type III,

 * but we look at the version in the ERSPAN header; should we report an

 * error if it's not version 2?).

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/expert.h>

#include <epan/tfs.h>

#include "packet-gre.h"

void proto_register_erspan(void);

void proto_reg_handoff_erspan(void);

static int proto_erspan;

static int ett_erspan;

static int hf_erspan_version;

static int hf_erspan_vlan;

static int hf_erspan_cos;

static int hf_erspan_encap;

static int hf_erspan_truncated;

static int hf_erspan_spanid;

static int hf_erspan_reserved;

static int hf_erspan_index;

static int hf_erspan_timestamp;

static int hf_erspan_direction;

static int hf_erspan_bso;

static int hf_erspan_sgt;

static int hf_erspan_p;

static int hf_erspan_ft;

static int hf_erspan_hw;

static int hf_erspan_gra;

static int hf_erspan_o;

/* Optional Sub-header */

static int hf_erspan_platid;

/* Platform ID = 1 */

static int hf_erspan_pid1_rsvd1;

static int hf_erspan_pid1_domain_id;

static int hf_erspan_pid1_port_index;

/* Platform ID = 3 */

static int hf_erspan_pid3_rsvd1;

static int hf_erspan_pid3_port_index;

static int hf_erspan_pid3_timestamp;

/* Platform ID = 4 */

static int hf_erspan_pid4_rsvd1;

static int hf_erspan_pid4_rsvd2;

static int hf_erspan_pid4_rsvd3;

/* Platform ID = 5 or 6 */

static int hf_erspan_pid5_switchid;

static int hf_erspan_pid5_port_index;

static int hf_erspan_pid5_timestamp;

/* Platform ID = 7 (or 0) */

static int hf_erspan_pid7_rsvd1;

static int hf_erspan_pid7_source_index;

static int hf_erspan_pid7_timestamp;

/* ID: 0x0, 0x2, 0x8-0x63 are reserved. */

static int hf_erspan_pid_rsvd;

static expert_field ei_erspan_version_unknown;

static const true_false_string tfs_direction = { "Egress", "Ingress" };

#define ERSPAN_ENCAP_00 0

#define ERSPAN_ENCAP_01 1

#define ERSPAN_ENCAP_10 2

#define ERSPAN_ENCAP_11 3

static const value_string erspan_encap_vals[] = {

  {ERSPAN_ENCAP_00, "Originally without VLAN tag"},

  {ERSPAN_ENCAP_01, "Originally ISL encapsulated"},

  {ERSPAN_ENCAP_10, "Originally 802.1Q encapsulated"},

  {ERSPAN_ENCAP_11, "VLAN tag preserved in frame"},

  {0, NULL}

};

static const value_string erspan_bso_vals[] = {

  {0, "Good or unknown integrity"},

  {1, "Short frame"},

  {2, "Oversized frame"},

  {3, "CRC or alignment error"},

  {0, NULL},

};

static const value_string erspan_truncated_vals[] = {

  {0, "Not truncated"},

  {1, "Truncated"},

  {0, NULL},

};

#define ERSPAN_FT_ETHERNET  0

#define ERSPAN_FT_IP    2

static const value_string erspan_ft_vals[] = {

  {ERSPAN_FT_ETHERNET, "Ethernet"},

  {ERSPAN_FT_IP, "IP"},

  {0, NULL},

};

static const value_string erspan_version_vals[] = {

  {1, "Type II"},

  {2, "Type III"},

  {0, NULL},

};

static const value_string erspan_granularity_vals[] = {

  {0, "100 microseconds"},

  {1, "100 nanoseconds"},

  {2, "IEEE 1588"},

  {3, "Custom granularity"},

  {0, NULL}

};

static dissector_handle_t ethnofcs_handle;

static int

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

{

  proto_item *ti;

  proto_tree *erspan_tree = NULL;

  tvbuff_t *frame_tvb;

  uint32_t offset = 0;

  uint32_t version;

  uint32_t frame_type = ERSPAN_FT_ETHERNET;

  ti = proto_tree_add_item(tree, proto_erspan, tvb, offset, -1,

      ENC_NA);

  erspan_tree = proto_item_add_subtree(ti, ett_erspan);

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

  col_set_str(pinfo->cinfo, COL_INFO, "ERSPAN:");

  /*

   * Dissect the version field, which is present in all versions

   * of the header.

   */

  proto_tree_add_item_ret_uint(erspan_tree, hf_erspan_version, tvb,

    offset, 2, ENC_BIG_ENDIAN, &version);

  /* Put the version in the header. */

  proto_item_append_text(ti, " %s", val_to_str_const(version, erspan_version_vals, "Unknown"));

  /*

   * Now dissect the rest of the header, based on the version.

   */

  switch (version) {

  case 1: {

    uint32_t vlan, vlan_encap;

    proto_tree_add_item_ret_uint(erspan_tree, hf_erspan_vlan, tvb, offset, 2,

      ENC_BIG_ENDIAN, &vlan);

    offset += 2;

    proto_tree_add_item(erspan_tree, hf_erspan_cos, tvb, offset, 2,

      ENC_BIG_ENDIAN);

    proto_tree_add_item_ret_uint(erspan_tree, hf_erspan_encap, tvb,

      offset, 2, ENC_BIG_ENDIAN, &vlan_encap);

    if (pinfo->vlan_id == 0 && vlan_encap != ERSPAN_ENCAP_11) {

      pinfo->vlan_id = vlan;

    }

    proto_tree_add_item(erspan_tree, hf_erspan_truncated, tvb, offset, 2,

      ENC_BIG_ENDIAN);

    proto_tree_add_item(erspan_tree, hf_erspan_spanid, tvb, offset, 2,

      ENC_BIG_ENDIAN);

    offset += 2;

    proto_tree_add_item(erspan_tree, hf_erspan_reserved, tvb,

      offset, 4, ENC_BIG_ENDIAN);

    proto_tree_add_item(erspan_tree, hf_erspan_index, tvb,

      offset, 4, ENC_BIG_ENDIAN);

    offset += 4;

    break;

    }

  case 2: {

    uint32_t subheader = 0;

    uint32_t vlan;

    proto_tree_add_item_ret_uint(erspan_tree, hf_erspan_vlan, tvb, offset, 2,

      ENC_BIG_ENDIAN, &vlan);

    pinfo->vlan_id = vlan;

    offset += 2;

    proto_tree_add_item(erspan_tree, hf_erspan_cos, tvb, offset, 2,

      ENC_BIG_ENDIAN);

    proto_tree_add_item(erspan_tree, hf_erspan_bso, tvb, offset, 2,

      ENC_BIG_ENDIAN);

    proto_tree_add_item(erspan_tree, hf_erspan_truncated, tvb, offset, 2,

      ENC_BIG_ENDIAN);

    proto_tree_add_item(erspan_tree, hf_erspan_spanid, tvb, offset, 2,

      ENC_BIG_ENDIAN);

    offset += 2;

    proto_tree_add_item(erspan_tree, hf_erspan_timestamp, tvb,

      offset, 4, ENC_BIG_ENDIAN);

    offset += 4;

    proto_tree_add_item(erspan_tree, hf_erspan_sgt, tvb,

      offset, 2, ENC_BIG_ENDIAN);

    offset += 2;

    proto_tree_add_item(erspan_tree, hf_erspan_p, tvb,

      offset, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item_ret_uint(erspan_tree, hf_erspan_ft, tvb,

      offset, 2, ENC_BIG_ENDIAN, &frame_type);

    proto_tree_add_item(erspan_tree, hf_erspan_hw, tvb,

      offset, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(erspan_tree, hf_erspan_direction, tvb,

      offset, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(erspan_tree, hf_erspan_gra, tvb,

      offset, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item_ret_uint(erspan_tree, hf_erspan_o, tvb,

      offset, 2, ENC_BIG_ENDIAN, &subheader);

    offset += 2;

    /* Platform Specific SubHeader, 8 octets, optional */

    if (subheader) {

      int32_t platform_id = tvb_get_ntohl(tvb, offset) >> 26;

      proto_tree_add_item(erspan_tree, hf_erspan_platid, tvb,

          offset, 4, ENC_BIG_ENDIAN);

      switch (platform_id) {

        case 1:

          proto_tree_add_item(erspan_tree, hf_erspan_pid1_rsvd1,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          proto_tree_add_item(erspan_tree, hf_erspan_pid1_domain_id,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          proto_tree_add_item(erspan_tree, hf_erspan_pid1_port_index,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          break;

        case 3:

          proto_tree_add_item(erspan_tree, hf_erspan_pid3_rsvd1,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          proto_tree_add_item(erspan_tree, hf_erspan_pid3_port_index,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          proto_tree_add_item(erspan_tree, hf_erspan_pid3_timestamp,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          break;

        case 4:

          proto_tree_add_item(erspan_tree, hf_erspan_pid4_rsvd1, tvb,

            offset, 4, ENC_BIG_ENDIAN);

          proto_tree_add_item(erspan_tree, hf_erspan_pid4_rsvd2, tvb,

            offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          proto_tree_add_item(erspan_tree, hf_erspan_pid4_rsvd3, tvb,

            offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          break;

        case 5:

        case 6:

          proto_tree_add_item(erspan_tree, hf_erspan_pid5_switchid,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          proto_tree_add_item(erspan_tree, hf_erspan_pid5_port_index,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          proto_tree_add_item(erspan_tree, hf_erspan_pid5_timestamp,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          break;

        case 7:

        case 0: /* In some implementations it is used as an alias to 0x07. */

          proto_tree_add_item(erspan_tree, hf_erspan_pid7_rsvd1,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          proto_tree_add_item(erspan_tree, hf_erspan_pid7_source_index,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          proto_tree_add_item(erspan_tree, hf_erspan_pid7_timestamp,

            tvb, offset, 4, ENC_BIG_ENDIAN);

          offset += 4;

          break;

        default:

          /* ID: 0x0, 0x2, 0x8-0x63 are reserved. */

          proto_tree_add_item(erspan_tree, hf_erspan_pid_rsvd,

            tvb, offset, 8, ENC_BIG_ENDIAN);

          offset += 8;

          break;

      }

    }

    break;

    }

  default: {

    proto_item *ti_ver;

    ti_ver = proto_tree_add_item(erspan_tree, hf_erspan_version, tvb, offset, 2,

      ENC_BIG_ENDIAN);

    expert_add_info(pinfo, ti_ver, &ei_erspan_version_unknown);

    return 2;

    }

  }

  frame_tvb = tvb_new_subset_remaining(tvb, offset);

  switch (frame_type) {

  case ERSPAN_FT_ETHERNET:

    call_dissector(ethnofcs_handle, frame_tvb, pinfo, tree);

    break;

  default:

    call_data_dissector(frame_tvb, pinfo, tree);

    break;

  }

  return tvb_captured_length(tvb);

}

static int

dissect_erspan_88BE(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)

{

  bool has_erspan_header;

  /*

   * Frames with a GRE type of 0x88BE have an ERSPAN header iff

   * the "sequence number present" flag is set in the GRE header.

   */

  if (data == NULL) {

    /*

     * We weren't handed the GRE flags or version.

     *

     * This can happen if a Linux cooked capture is done and

     * we get a packet from an "ipgre" interface.

     *

     * For now, we just assume this is Type I, with no

     * header.

     */

    has_erspan_header = false;

  } else {

    gre_hdr_info_t *gre_hdr_info = (gre_hdr_info_t *)data;

    if (gre_hdr_info->flags_and_ver & GRE_SEQUENCE) {

      /*

       * "sequence number present" set, so it has a

       * header.

       */

      has_erspan_header = true;

    } else {

      /*

       * Not present, so no header.

       */

      has_erspan_header = false;

    }

  }

  if (has_erspan_header) {

    /*

     * We have a header, so dissect it, and then handle

     * the payload.

     */

    return dissect_erspan(tvb, pinfo, tree, data);

  } else {

    /*

     * No header, so just hand the payload off to the

     * Ethernet dissector.  Put in a placeholder for

     * ERSPAN.

     */

    proto_item *ti;

    ti = proto_tree_add_item(tree, proto_erspan, tvb, 0, 0,

        ENC_NA);

    proto_item_append_text(ti, " Type I");

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

    col_set_str(pinfo->cinfo, COL_INFO, "ERSPAN:");

    call_dissector(ethnofcs_handle, tvb, pinfo, tree);

    return tvb_captured_length(tvb);

  }

}

static int

dissect_erspan_22EB(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)

{

  /*

   * Frames with a GRE type of 0x22EB always have an ERSPAN

   * header.

   */

  return dissect_erspan(tvb, pinfo, tree, data);

}

void

proto_register_erspan(void)

{

  expert_module_t* expert_erspan;

  static hf_register_info hf[] = {

    { &hf_erspan_version,

    { "Version",  "erspan.version", FT_UINT16, BASE_DEC, VALS(erspan_version_vals),

      0xf000, NULL, HFILL }},

    { &hf_erspan_vlan,

    { "Vlan", "erspan.vlan", FT_UINT16, BASE_DEC, NULL,

      0x0fff, NULL, HFILL }},

    { &hf_erspan_cos,

    { "COS",  "erspan.cos", FT_UINT16, BASE_DEC, NULL,

      0xe000, NULL, HFILL }},

    { &hf_erspan_encap,

    { "Encap",  "erspan.encap", FT_UINT16, BASE_DEC, VALS(erspan_encap_vals),

      0x1800, NULL, HFILL }},

    { &hf_erspan_bso,

    { "Bad/Short/Oversized",  "erspan.bso", FT_UINT16, BASE_DEC, VALS(erspan_bso_vals),

      0x1800, NULL, HFILL }},

    { &hf_erspan_truncated,

    { "Truncated",  "erspan.truncated", FT_UINT16, BASE_DEC, VALS(erspan_truncated_vals),

      0x0400, "ERSPAN packet exceeded the MTU size", HFILL }},

    { &hf_erspan_spanid,

    { "SpanID", "erspan.spanid", FT_UINT16, BASE_DEC, NULL,

      0x03ff, NULL, HFILL }},

    { &hf_erspan_reserved,

    { "Reserved", "erspan.reserved", FT_UINT32, BASE_DEC, NULL,

      0xfff00000, NULL, HFILL }},

    { &hf_erspan_index,

    { "Index",  "erspan.index", FT_UINT32, BASE_DEC, NULL,

      0x000fffff, NULL, HFILL }},

    { &hf_erspan_timestamp,

    { "Timestamp",  "erspan.timestamp", FT_UINT32, BASE_DEC, NULL,

      0x0, NULL, HFILL }},

    { &hf_erspan_sgt,

    { "Security Group Tag", "erspan.sgt", FT_UINT16, BASE_DEC, NULL,

      0x0, NULL, HFILL }},

    { &hf_erspan_p,

    { "Has Ethernet PDU", "erspan.p", FT_UINT16, BASE_DEC, NULL,

      0x8000, NULL, HFILL }},

    { &hf_erspan_ft,

    { "Frame Type", "erspan.ft", FT_UINT16, BASE_DEC, VALS(erspan_ft_vals),

      0x7C00, NULL, HFILL }},

    { &hf_erspan_hw,

    { "Hardware ID", "erspan.hw", FT_UINT16, BASE_DEC, NULL,

      0x03f0, NULL, HFILL }},

    { &hf_erspan_gra,

    { "Timestamp granularity", "erspan.gra", FT_UINT16, BASE_DEC, VALS(erspan_granularity_vals),

      0x0006, NULL, HFILL }},

    { &hf_erspan_direction,

    { "Direction",  "erspan.direction", FT_BOOLEAN, 16, TFS(&tfs_direction),

      0x0008, NULL, HFILL }},

    { &hf_erspan_o,

    { "Optional Sub headers", "erspan.o", FT_UINT16, BASE_DEC, NULL,

      0x0001, NULL, HFILL }},

    /* Sub-header Fields, optional */

    { &hf_erspan_platid,

    { "Platform ID", "erspan.platid", FT_UINT32, BASE_DEC, NULL,

      0xfc000000, NULL, HFILL }},

    /* ID = 1 */

    { &hf_erspan_pid1_rsvd1,

    { "Reserved", "erspan.pid1.rsvd1", FT_UINT32, BASE_DEC, NULL,

      0x03fff000, NULL, HFILL }},

    { &hf_erspan_pid1_domain_id,

    { "VSM Domain ID", "erspan.pid1.vsmid", FT_UINT32, BASE_DEC, NULL,

      0x00000fff, NULL, HFILL }},

    { &hf_erspan_pid1_port_index,

    { "Port ID/Index", "erspan.pid1.port_index", FT_UINT32, BASE_DEC, NULL,

      0x0, NULL, HFILL }},

    /* ID = 3 */

    { &hf_erspan_pid3_rsvd1,

    { "Reserved", "erspan.pid3.rsvd1", FT_UINT32, BASE_DEC, NULL,

      0x03ffc000, NULL, HFILL }},

    { &hf_erspan_pid3_port_index,

    { "Port ID/Index", "erspan.pid3.port_index", FT_UINT32, BASE_DEC, NULL,

      0x00003fff, NULL, HFILL }},

    { &hf_erspan_pid3_timestamp,

    { "Upper 32-bit Timestamp", "erspan.pid3.timestamp", FT_UINT32, BASE_DEC, NULL,

      0x0, NULL, HFILL }},

    /* ID = 4 */

    { &hf_erspan_pid4_rsvd1,

    { "Reserved", "erspan.pid4.rsvd1", FT_UINT32, BASE_DEC, NULL,

      0x03ffc000, NULL, HFILL }},

    { &hf_erspan_pid4_rsvd2,

    { "Reserved", "erspan.pid4.rsvd2", FT_UINT32, BASE_DEC, NULL,

      0x00003fff, NULL, HFILL }},

    { &hf_erspan_pid4_rsvd3,

    { "Reserved", "erspan.pid4.rsvd3", FT_UINT32, BASE_DEC, NULL,

      0xffffffff, NULL, HFILL }},

    /* ID = 5 or 6 */

    { &hf_erspan_pid5_switchid,

    { "Switch ID", "erspan.pid5.switchid", FT_UINT32, BASE_DEC, NULL,

      0x03ff0000, NULL, HFILL }},

    { &hf_erspan_pid5_port_index,

    { "Port ID/Index", "erspan.pid5.port_index", FT_UINT32, BASE_DEC, NULL,

      0x0000ffff, NULL, HFILL }},

    { &hf_erspan_pid5_timestamp,

    { "Timestamp (seconds)", "erspan.pid5.timestamp", FT_UINT32, BASE_DEC, NULL,

      0x0, NULL, HFILL }},

    /* ID = 7 (or 0) */

    { &hf_erspan_pid7_rsvd1,

    { "Reserved", "erspan.pid7.rsvd1", FT_UINT32, BASE_DEC, NULL,

      0x03f00000, NULL, HFILL }},

    { &hf_erspan_pid7_source_index,

    { "Source Index", "erspan.pid7.source_index", FT_UINT32, BASE_DEC, NULL,

      0x000fffff, NULL, HFILL }},

    { &hf_erspan_pid7_timestamp,

    { "Upper 32-bit Timestamp", "erspan.pid7.timestamp", FT_UINT32, BASE_DEC, NULL,

      0x0, NULL, HFILL }},

    /* Reserved */

    { &hf_erspan_pid_rsvd,

    { "Reserved", "erspan.pid.rsvd", FT_UINT64, BASE_DEC, NULL,

      0x03ffffff, NULL, HFILL }},

  };

  static int *ett[] = {

    &ett_erspan,

  };

  static ei_register_info ei[] = {

    { &ei_erspan_version_unknown, { "erspan.version.unknown", PI_UNDECODED, PI_WARN, "Unknown version, please report or test to use fake ERSPAN preference", EXPFILL }},

  };

  proto_erspan = proto_register_protocol("Encapsulated Remote Switch Packet ANalysis", "ERSPAN", "erspan");

  proto_register_field_array(proto_erspan, hf, array_length(hf));

  proto_register_subtree_array(ett, array_length(ett));

  expert_erspan = expert_register_protocol(proto_erspan);

  expert_register_field_array(expert_erspan, ei, array_length(ei));

  register_dissector("erspan", dissect_erspan, proto_erspan);

}

void

proto_reg_handoff_erspan(void)

{

  dissector_handle_t erspan_88BE_handle;

  dissector_handle_t erspan_22EB_handle;

  ethnofcs_handle = find_dissector_add_dependency("eth_withoutfcs", proto_erspan);

  erspan_88BE_handle = create_dissector_handle(dissect_erspan_88BE, proto_erspan);

  dissector_add_uint("gre.proto", GRE_ERSPAN_88BE, erspan_88BE_handle);

  erspan_22EB_handle = create_dissector_handle(dissect_erspan_22EB, proto_erspan);

  dissector_add_uint("gre.proto", GRE_ERSPAN_22EB, erspan_22EB_handle);

}

/*

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

 *

 * Local variables:

 * c-basic-offset: 8

 * tab-width: 8

 * indent-tabs-mode: t

 * End:

 *

 * vi: set shiftwidth=8 tabstop=8 noexpandtab:

 * :indentSize=8:tabSize=8:noTabs=false:

 */