/* packet-glbp.c
 *
 * Cisco's GLBP:  Gateway Load Balancing Protocol
 *
 * Copyright 2007 Joerg Mayer (see AUTHORS file)
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

/*
 * Documentation:
 * http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.pdf
 *
 * TODO: This dissector has been written without specs, so much of it is
 *    guesswork. Also, there are still unknown elements in the message.
 * Some debug output:
 * GLBP: Fa0/0 Grp 1020 Hello  out VG Active  pri 100 vIP FE80::C800:8FF:FE64:AAAA
 *       hello 3000, hold 10000 VF 1 Active  pri 167 vMAC 0007.b403.fc01
 * GLBP: Fa0/0 Grp 1021 Hello  out VG Active  pri 100 vIP 10.20.20.100
 *       hello 3000, hold 10000 VF 1 Active  pri 167 vMAC 0007.b403.fd01
 */

#include "config.h"

#include <epan/packet.h>
#include <epan/expert.h>

void proto_register_glbp(void);
void proto_reg_handoff_glbp(void);

static dissector_handle_t glbp_handle;

#define GLBP_UDP_PORT 3222

static int proto_glbp = -1;
/* glbp header? */
static gint hf_glbp_version = -1;
static gint hf_glbp_unknown1 = -1;
static gint hf_glbp_group = -1;
static gint hf_glbp_unknown2 = -1;
static gint hf_glbp_ownerid = -1;
static gint hf_glbp_tlv = -1;
static gint hf_glbp_type = -1;
static gint hf_glbp_length = -1;
/* glbp type = 1 - hello */
static gint hf_glbp_hello_unknown10 = -1;
static gint hf_glbp_hello_vgstate = -1;
static gint hf_glbp_hello_unknown11 = -1;
static gint hf_glbp_hello_priority = -1;
static gint hf_glbp_hello_unknown12 = -1;
static gint hf_glbp_hello_helloint = -1;
static gint hf_glbp_hello_holdint = -1;
static gint hf_glbp_hello_redirect = -1;
static gint hf_glbp_hello_timeout = -1;
static gint hf_glbp_hello_unknown13 = -1;
static gint hf_glbp_hello_addrtype = -1;
static gint hf_glbp_hello_addrlen = -1;
static gint hf_glbp_hello_virtualipv4 = -1;
static gint hf_glbp_hello_virtualipv6 = -1;
static gint hf_glbp_hello_virtualunk = -1;
/* glbp type = 2 - Request/Response??? */
static gint hf_glbp_reqresp_forwarder = -1;
static gint hf_glbp_reqresp_vfstate = -1;
static gint hf_glbp_reqresp_unknown21 = -1;
static gint hf_glbp_reqresp_priority = -1;
static gint hf_glbp_reqresp_weight = -1;
static gint hf_glbp_reqresp_unknown22 = -1;
static gint hf_glbp_reqresp_virtualmac = -1;
/* glbp type = 3 - Auth */
static gint hf_glbp_auth_authtype = -1;
static gint hf_glbp_auth_authlength = -1;
static gint hf_glbp_auth_plainpass = -1;
static gint hf_glbp_auth_md5hash = -1;
static gint hf_glbp_auth_md5chainindex = -1;
static gint hf_glbp_auth_md5chainhash = -1;
static gint hf_glbp_auth_authunknown = -1;
/* unknown type */
static gint hf_glbp_unknown_data = -1;

static gint ett_glbp = -1;
static gint ett_glbp_tlv = -1;

/* filterable expert infos */
static expert_field ei_glbp_ipv4_wrong_length = EI_INIT;
static expert_field ei_glbp_ipv6_wrong_length = EI_INIT;
static expert_field ei_glbp_tlv_length_too_small = EI_INIT;
static expert_field ei_glbp_tlv_invalid_bytes_used = EI_INIT;

static const value_string glbp_type_vals[] = {
  { 1,  "Hello" },
  { 2,  "Request/Response?" },
  { 3,  "Auth" },

  { 0, NULL }
};

#if 0
static const value_string glbp_reqresp_forwarder_vals[] = {
  { 0,  "Request?" },
  { 2,  "Response?" },

  { 0, NULL }
};
#endif

static const value_string glbp_addr_type_vals[] = {
  { 1,  "IPv4" },
  { 2,  "IPv6" },

  { 0, NULL }
};

static const value_string glbp_auth_type_vals[] = {
  { 0,  "None" },
  { 1,  "Plain text" },
  { 2,  "MD5 string" },
  { 3,  "MD5 chain" },

  { 0, NULL }
};

#if 0
static const value_string glbp_loadbalancing_vals[] = {
  { x,  "None (AVG only)" },
  { x,  "Weighted" },
  { x,  "Host dependent" },
  { x,  "Round robin" },

  { 0, NULL }
};
#endif

static const value_string glbp_vgstate_vals[] = {
#if 0
  {    x,  "Disabled" },
  {    x,  "Initial" },
#endif
  {    4,  "Listen" },
  {    8,  "Speak" },
  { 0x10,  "Standby" },
  { 0x20,  "Active" },

  { 0, NULL }
};

static const value_string glbp_vfstate_vals[] = {
#if 0
  {    x,  "Disabled" },
  {    x,  "Initial" },
#endif
  {    4,  "Listen" },
  { 0x20,  "Active" },

  { 0, NULL }
};

static int
dissect_glbp_hello(tvbuff_t *tvb, int offset,
        packet_info *pinfo, proto_tree *tlv_tree)
{
  guint8 addrtype;
  guint8 addrlen;

  proto_tree_add_item(tlv_tree, hf_glbp_hello_unknown10, tvb, offset, 1, ENC_NA);
  offset ++;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_vgstate,   tvb, offset, 1, ENC_BIG_ENDIAN);
  offset ++;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_unknown11, tvb, offset, 1, ENC_NA);
  offset ++;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_priority,  tvb, offset, 1, ENC_BIG_ENDIAN);
  offset++;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_unknown12, tvb, offset, 2, ENC_NA);
  offset += 2;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_helloint,  tvb, offset, 4, ENC_BIG_ENDIAN);
  offset += 4;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_holdint,   tvb, offset, 4, ENC_BIG_ENDIAN);
  offset += 4;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_redirect,  tvb, offset, 2, ENC_BIG_ENDIAN);
  offset += 2;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_timeout,   tvb, offset, 2, ENC_BIG_ENDIAN);
  offset += 2;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_unknown13, tvb, offset, 2, ENC_NA);
  offset += 2;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_addrtype,  tvb, offset, 1, ENC_BIG_ENDIAN);
  addrtype = tvb_get_guint8(                             tvb, offset);
  offset++;
  proto_tree_add_item(tlv_tree, hf_glbp_hello_addrlen,   tvb, offset, 1, ENC_BIG_ENDIAN);
  addrlen = tvb_get_guint8(tvb, offset);
  offset++;
  switch (addrtype) {
    case 1:
    if (addrlen != 4) {
      expert_add_info_format(pinfo, NULL, &ei_glbp_ipv4_wrong_length,
        "Wrong IPv4 address length: %u", addrlen);
      return offset + addrlen;
    }
    proto_tree_add_item(tlv_tree, hf_glbp_hello_virtualipv4, tvb, offset, addrlen, ENC_BIG_ENDIAN);
    break;
  case 2:
    if (addrlen != 16) {
      expert_add_info_format(pinfo, NULL, &ei_glbp_ipv6_wrong_length,
        "Wrong IPv6 address length: %u", addrlen);
      return offset + addrlen;
    }
    proto_tree_add_item(tlv_tree, hf_glbp_hello_virtualipv6, tvb, offset, addrlen, ENC_NA);
    break;
  default:
    proto_tree_add_item(tlv_tree, hf_glbp_hello_virtualunk, tvb, offset, addrlen, ENC_NA);
    break;
  }
  offset += addrlen;

  col_append_fstr(pinfo->cinfo, COL_INFO, ", %s",
    val_to_str(addrtype, glbp_addr_type_vals, "%d"));

  return offset;
}


static int
dissect_glbp_reqresp(tvbuff_t *tvb, int offset,
        packet_info *pinfo _U_, proto_tree *tlv_tree)
{
  proto_tree_add_item(tlv_tree, hf_glbp_reqresp_forwarder,  tvb, offset, 1, ENC_BIG_ENDIAN);
  offset++;
  proto_tree_add_item(tlv_tree, hf_glbp_reqresp_vfstate,    tvb, offset, 1, ENC_BIG_ENDIAN);
  offset++;
  proto_tree_add_item(tlv_tree, hf_glbp_reqresp_unknown21,  tvb, offset, 1, ENC_NA);
  offset += 1;
  proto_tree_add_item(tlv_tree, hf_glbp_reqresp_priority,   tvb, offset, 1, ENC_BIG_ENDIAN);
  offset++;
  proto_tree_add_item(tlv_tree, hf_glbp_reqresp_weight,     tvb, offset, 1, ENC_BIG_ENDIAN);
  offset++;
  proto_tree_add_item(tlv_tree, hf_glbp_reqresp_unknown22,  tvb, offset, 7, ENC_NA);
  offset += 7;
  proto_tree_add_item(tlv_tree, hf_glbp_reqresp_virtualmac, tvb, offset, 6, ENC_NA);
  offset += 6;

  return offset;
}

static int
dissect_glbp_auth(tvbuff_t *tvb, int offset,
        packet_info *pinfo _U_, proto_tree *tlv_tree)
{
  guint8 authtype;
  guint8 authlength;

  proto_tree_add_item(tlv_tree, hf_glbp_auth_authtype,   tvb, offset, 1, ENC_BIG_ENDIAN);
  authtype = tvb_get_guint8(tvb, offset);
  offset++;
  proto_tree_add_item(tlv_tree, hf_glbp_auth_authlength, tvb, offset, 1, ENC_BIG_ENDIAN);
  authlength = tvb_get_guint8(tvb, offset);
  offset++;
  switch(authtype) {
  case 1:
    proto_tree_add_item(tlv_tree, hf_glbp_auth_plainpass, tvb, offset, authlength, ENC_ASCII);
    offset += authlength;
    break;
  case 2:
    proto_tree_add_item(tlv_tree, hf_glbp_auth_md5hash,   tvb, offset, authlength, ENC_NA);
    offset += authlength;
    break;
  case 3:
    proto_tree_add_item(tlv_tree, hf_glbp_auth_md5chainindex, tvb, offset, 4, ENC_BIG_ENDIAN);
    proto_tree_add_item(tlv_tree, hf_glbp_auth_md5chainhash,  tvb, offset+4, authlength-4, ENC_NA);
    offset += authlength;
    break;
  default:
    proto_tree_add_item(tlv_tree, hf_glbp_auth_authunknown, tvb, offset, authlength, ENC_NA);
    offset += authlength;
    break;
  }

  return offset;
}

static int
dissect_glbp_unknown(tvbuff_t *tvb, int offset, guint32 length,
        packet_info *pinfo _U_, proto_tree *tlv_tree)
{
  proto_tree_add_item(tlv_tree, hf_glbp_unknown_data, tvb, offset, length, ENC_NA);
  offset += length;

  return offset;
}

static int
dissect_glbp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  proto_tree *glbp_tree;
  proto_tree *tlv_tree;
  proto_item *ti;
  guint8      type;
  int         offset    = 0;
  int         lastoffset;
  guint8      length;
  guint16     group;

  group = tvb_get_ntohs(tvb, 2);

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "GLBP");
  col_add_fstr(pinfo->cinfo, COL_INFO, "G: %d", group);

  ti = proto_tree_add_item(tree, proto_glbp, tvb, 0, -1, ENC_NA);
  glbp_tree = proto_item_add_subtree(ti, ett_glbp);

  /* glbp header? */
  proto_tree_add_item(glbp_tree, hf_glbp_version, tvb, offset, 1,  ENC_BIG_ENDIAN);
  offset++;
  proto_tree_add_item(glbp_tree, hf_glbp_unknown1, tvb, offset, 1,  ENC_BIG_ENDIAN);
  offset++;
  proto_tree_add_item(glbp_tree, hf_glbp_group, tvb, offset, 2,  ENC_BIG_ENDIAN);
  offset += 2;
  proto_tree_add_item(glbp_tree, hf_glbp_unknown2, tvb, offset, 2,  ENC_NA);
  offset += 2;
  proto_tree_add_item(glbp_tree, hf_glbp_ownerid, tvb, offset, 6, ENC_NA);
  offset += 6;
  while (tvb_reported_length_remaining(tvb, offset) > 0) {

    type = tvb_get_guint8(tvb, offset);
    length = tvb_get_guint8(tvb, offset+1);
    if (length < 2) {
      expert_add_info_format(pinfo, NULL, &ei_glbp_tlv_length_too_small,
        "Length %u too small", length);
      return offset;
    }
    length -= 2;

    ti = proto_tree_add_item(glbp_tree, hf_glbp_tlv, tvb, offset, length+2, ENC_BIG_ENDIAN);
    tlv_tree = proto_item_add_subtree(ti, ett_glbp_tlv);
    proto_item_append_text(ti, " l=%d, t=%s", length+2,
                           val_to_str(type, glbp_type_vals, "%d"));

    proto_tree_add_item(tlv_tree, hf_glbp_type, tvb, offset, 1,  ENC_BIG_ENDIAN);
    offset++;
    proto_tree_add_item(tlv_tree, hf_glbp_length, tvb, offset, 1,  ENC_BIG_ENDIAN);
    offset++;
    col_append_fstr(pinfo->cinfo, COL_INFO, ", %s",
                    val_to_str(type, glbp_type_vals, "%d"));

    lastoffset = offset;
    switch(type) {
    case 1: /* Hello */
      offset = dissect_glbp_hello(tvb, offset, pinfo, tlv_tree);
      break;
    case 2: /* Request/Response */
      offset = dissect_glbp_reqresp(tvb, offset, pinfo, tlv_tree);
      break;
    case 3: /* Plaintext auth */
      offset = dissect_glbp_auth(tvb, offset, pinfo, tlv_tree);
      break;
    default:
      offset = dissect_glbp_unknown(tvb, offset, length, pinfo, tlv_tree);
      break;
    }
    if (lastoffset >= offset) {
      expert_add_info(pinfo, NULL, &ei_glbp_tlv_invalid_bytes_used);
      return lastoffset;
    }
    /* Skip over trailing bytes before starting with the next element */
    if (lastoffset + length > offset)
      offset = lastoffset + length;
  }
  return offset;
}

static gboolean
test_glbp(tvbuff_t *tvb, packet_info *pinfo)
{
  guint32 unknown1;
  if ( tvb_captured_length(tvb) < 2)
    return FALSE;
  unknown1 = tvb_get_guint8(tvb, 1);
  if (tvb_get_guint8(tvb, 0) != 1 /* version? */
      || unknown1 > 4
      || pinfo->srcport != pinfo->destport
#if 0 /* XXX */
      || unknown1 == 0 && pinfo->net_dst != ipv4:224.0.0.102
      && pinfo->net_dst != ipv6:...
      || unknown1 == 0 && pinfo->dl_src != ether:c2-00-7c-b8-00-00
#endif
    ) {
    return FALSE;
  }
  return TRUE;
}

static int
dissect_glbp_static(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
  if ( !test_glbp(tvb, pinfo) ) {
    return 0;
  }
  return dissect_glbp(tvb, pinfo, tree);
}


void
proto_register_glbp(void)
{
  static hf_register_info hf[] = {
    /* Header */
    { &hf_glbp_version,
      { "Version?",           "glbp.version", FT_UINT8, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_unknown1,
      { "Unknown1",           "glbp.unknown1", FT_UINT8, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_group,
      { "Group",              "glbp.group", FT_UINT16, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_unknown2,
      { "Unknown2",           "glbp.unknown2", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_ownerid,
      { "Owner ID",           "glbp.ownerid", FT_ETHER, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_tlv,
      { "TLV",                "glbp.tlv", FT_PROTOCOL, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_type,
      { "Type",               "glbp.type", FT_UINT8, BASE_DEC, VALS(glbp_type_vals),
        0x0, NULL, HFILL }},

    { &hf_glbp_length,
      { "Length",             "glbp.length", FT_UINT8, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    /* type = 1 - hello */
    { &hf_glbp_hello_unknown10,
      { "Unknown1-0",         "glbp.hello.unknown10", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_vgstate,
      { "VG state?",          "glbp.hello.vgstate", FT_UINT8, BASE_DEC, VALS(glbp_vgstate_vals),
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_unknown11,
      { "Unknown1-1",         "glbp.hello.unknown11", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_priority,
      { "Priority",           "glbp.hello.priority", FT_UINT8, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_unknown12,
      { "Unknown1-2",         "glbp.hello.unknown12", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_helloint,
      { "Helloint",           "glbp.hello.helloint", FT_UINT32, BASE_DEC, NULL,
        0x0, "Hello interval [msec]", HFILL }},

    { &hf_glbp_hello_holdint,
      { "Holdint",            "glbp.hello.holdint", FT_UINT32, BASE_DEC, NULL,
        0x0, "Hold interval [msec]", HFILL }},

    { &hf_glbp_hello_redirect,
      { "Redirect",           "glbp.hello.redirect", FT_UINT16, BASE_DEC, NULL,
        0x0, "Redirect interval [sec]", HFILL }},

    { &hf_glbp_hello_timeout,
      { "Timeout",            "glbp.hello.timeout", FT_UINT16, BASE_DEC, NULL,
        0x0, "Forwarder timeout interval [sec]", HFILL }},

    { &hf_glbp_hello_unknown13,
      { "Unknown1-3",         "glbp.hello.unknown13", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_addrtype,
      { "Address type",       "glbp.hello.addrtype", FT_UINT8, BASE_DEC, VALS(glbp_addr_type_vals),
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_addrlen,
      { "Address length",     "glbp.hello.addrlen", FT_UINT8, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_virtualipv4,
      { "Virtual IPv4",       "glbp.hello.virtualipv4", FT_IPv4, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_virtualipv6,
      { "Virtual IPv6",       "glbp.hello.virtualipv6", FT_IPv6, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_hello_virtualunk,
      { "Virtual Unknown",    "glbp.hello.virtualunk", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    /* type = 2 - request/response??? */
    { &hf_glbp_reqresp_forwarder,
      { "Forwarder?",         "glbp.reqresp.forwarder", FT_UINT8, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_reqresp_vfstate,
      { "VF state?",          "glbp.reqresp.vfstate", FT_UINT8, BASE_DEC, VALS(glbp_vfstate_vals),
        0x0, NULL, HFILL }},

    { &hf_glbp_reqresp_unknown21,
      { "Unknown2-1",         "glbp.reqresp.unknown21", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_reqresp_priority,
      { "Priority",           "glbp.reqresp.priority", FT_UINT8, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_reqresp_weight,
      { "Weight",             "glbp.reqresp.weight", FT_UINT8, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_reqresp_unknown22,
      { "Unknown2-2",         "glbp.reqresp.unknown22", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_reqresp_virtualmac,
      { "Virtualmac",         "glbp.reqresp.virtualmac", FT_ETHER, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    /* type = 3 - auth */
    { &hf_glbp_auth_authtype,
      { "Authtype",           "glbp.auth.authtype", FT_UINT8, BASE_DEC, VALS(glbp_auth_type_vals),
        0x0, NULL, HFILL }},

    { &hf_glbp_auth_authlength,
      { "Authlength",         "glbp.auth.authlength", FT_UINT8, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_auth_plainpass,
      { "Plain pass",         "glbp.auth.plainpass", FT_STRING, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_auth_md5hash,
      { "MD5-string hash",    "glbp.auth.md5hash", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_auth_md5chainindex,
      { "MD5-chain index",    "glbp.auth.md5chainindex", FT_UINT32, BASE_DEC, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_auth_md5chainhash,
      { "MD5-chain hash",     "glbp.auth.md5chainhash", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    { &hf_glbp_auth_authunknown,
      { "Unknown auth value", "glbp.auth.authunknown", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

    /* type = unknown */
    { &hf_glbp_unknown_data,
      { "Unknown TLV data",   "glbp.unknown.data", FT_BYTES, BASE_NONE, NULL,
        0x0, NULL, HFILL }},

  };
  static gint *ett[] = {
    &ett_glbp,
    &ett_glbp_tlv,
  };

  static ei_register_info ei[] = {
    { &ei_glbp_ipv4_wrong_length,
      { "glbp.ipv4_wrong_length", PI_MALFORMED, PI_ERROR,
        "Wrong IPv4 address length: %u",
        EXPFILL }},
    { &ei_glbp_ipv6_wrong_length,
      { "glbp.ipv6_wrong_length", PI_MALFORMED, PI_ERROR,
        "Wrong IPv6 address length: %u",
        EXPFILL }},
    { &ei_glbp_tlv_length_too_small,
      { "glbp.tlv_length_too_small", PI_MALFORMED, PI_ERROR,
        "Length %u too small",
        EXPFILL }},
    { &ei_glbp_tlv_invalid_bytes_used,
      { "glbp.tlv_invalid_bytes_used", PI_MALFORMED, PI_ERROR,
        "Zero or negative length",
        EXPFILL }},
  };

  expert_module_t* expert_glbp;

  proto_glbp = proto_register_protocol("Gateway Load Balancing Protocol", "GLBP", "glbp");

  proto_register_field_array(proto_glbp, hf, array_length(hf));
  proto_register_subtree_array(ett, array_length(ett));
  expert_glbp = expert_register_protocol(proto_glbp);
  expert_register_field_array(expert_glbp, ei, array_length(ei));

  glbp_handle = register_dissector("glbp", dissect_glbp_static, proto_glbp);
}

void
proto_reg_handoff_glbp(void)
{
  dissector_add_uint_with_preference("udp.port", GLBP_UDP_PORT, glbp_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:
 */