2013-06-14 14:35:34 +00:00
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/* packet-carp.c
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* Routines for the Common Address Redundancy Protocol (CARP)
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* Copyright 2013, Uli Heilmeier <uh@heilmeier.eu>
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* Based on packet-vrrp.c by Heikki Vatiainen <hessu@cs.tut.fi>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/ipproto.h>
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#include <epan/in_cksum.h>
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2013-12-15 23:44:12 +00:00
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void proto_register_carp(void);
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void proto_reg_handoff_carp(void);
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2013-06-14 14:35:34 +00:00
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static gint proto_carp = -1;
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static gint ett_carp = -1;
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static gint ett_carp_ver_type = -1;
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static gint hf_carp_ver_type = -1;
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static gint hf_carp_version = -1;
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static gint hf_carp_type = -1;
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static gint hf_carp_vhid = -1;
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static gint hf_carp_advskew = -1;
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static gint hf_carp_authlen = -1;
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static gint hf_carp_demotion = -1;
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static gint hf_carp_advbase = -1;
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static gint hf_carp_counter = -1;
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static gint hf_carp_hmac = -1;
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#define CARP_VERSION_MASK 0xf0
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#define CARP_TYPE_MASK 0x0f
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#define CARP_TYPE_ADVERTISEMENT 1
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static const value_string carp_type_vals[] = {
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{CARP_TYPE_ADVERTISEMENT, "Advertisement"},
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{0, NULL}
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};
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static gboolean
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2013-06-14 14:56:00 +00:00
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test_carp_packet(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree _U_, void *data _U_)
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2013-06-14 14:35:34 +00:00
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{
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guint8 ver_type, version, auth_length;
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2013-10-13 19:56:52 +00:00
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/* First some simple check if the data is
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2013-06-14 14:35:34 +00:00
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really CARP */
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2014-06-19 17:18:16 +00:00
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if (tvb_length(tvb) < 36)
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2013-06-14 14:35:34 +00:00
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return FALSE;
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/* Version must be 1 or 2, type must be in carp_type_vals */
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ver_type = tvb_get_guint8(tvb, 0);
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version = hi_nibble(ver_type);
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if ((version == 0) || (version > 2) ||
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(try_val_to_str(lo_nibble(ver_type), carp_type_vals) == NULL))
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return FALSE;
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auth_length = tvb_get_guint8(tvb, 3);
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if ( auth_length != 7 )
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return FALSE;
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return TRUE;
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}
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static int
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2013-12-10 03:11:34 +00:00
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dissect_carp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
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2013-06-14 14:35:34 +00:00
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{
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int offset = 0;
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gint carp_len;
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guint8 vhid;
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vec_t cksum_vec[4];
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proto_item *ti, *tv;
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proto_tree *carp_tree, *ver_type_tree;
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guint8 ver_type;
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guint16 cksum, computed_cksum;
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/* Make sure it's a CARP packet */
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if (!test_carp_packet(tvb, pinfo, tree, data))
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return 0;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "CARP");
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col_clear(pinfo->cinfo, COL_INFO);
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vhid = tvb_get_guint8(tvb, 1);
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col_add_fstr(pinfo->cinfo, COL_INFO, "%s (Virtual Host ID: %u)",
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"Announcement", vhid);
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ti = proto_tree_add_item(tree, proto_carp, tvb, 0, -1, ENC_NA);
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carp_tree = proto_item_add_subtree(ti, ett_carp);
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ver_type = tvb_get_guint8(tvb, 0);
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tv = proto_tree_add_uint_format(carp_tree, hf_carp_ver_type,
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tvb, offset, 1, ver_type,
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"Version %u, Packet type %u (%s)",
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hi_nibble(ver_type), lo_nibble(ver_type),
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val_to_str_const(lo_nibble(ver_type), carp_type_vals, "Unknown"));
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ver_type_tree = proto_item_add_subtree(tv, ett_carp_ver_type);
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proto_tree_add_uint(ver_type_tree, hf_carp_version, tvb, offset, 1, ver_type);
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proto_tree_add_uint(ver_type_tree, hf_carp_type, tvb, offset, 1, ver_type);
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offset++;
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proto_tree_add_item(carp_tree, hf_carp_vhid, tvb, offset, 1, ENC_BIG_ENDIAN);
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offset++;
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proto_tree_add_item(carp_tree, hf_carp_advskew, tvb, offset, 1, ENC_BIG_ENDIAN);
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offset++;
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proto_tree_add_item(carp_tree, hf_carp_authlen, tvb,
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offset, 1, ENC_NA);
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offset++;
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proto_tree_add_item(carp_tree, hf_carp_demotion, tvb, offset, 1, ENC_BIG_ENDIAN);
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offset++;
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proto_tree_add_item(carp_tree, hf_carp_advbase, tvb, offset, 1, ENC_BIG_ENDIAN);
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offset++;
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cksum = tvb_get_ntohs(tvb, offset);
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carp_len = (gint)tvb_reported_length(tvb);
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2014-06-19 17:18:16 +00:00
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if (!pinfo->fragmented && (gint)tvb_length(tvb) >= carp_len) {
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2013-06-14 14:35:34 +00:00
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/* The packet isn't part of a fragmented datagram
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and isn't truncated, so we can checksum it. */
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cksum_vec[0].ptr = tvb_get_ptr(tvb, 0, carp_len);
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cksum_vec[0].len = carp_len;
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computed_cksum = in_cksum(&cksum_vec[0], 1);
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if (computed_cksum == 0) {
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proto_tree_add_text(carp_tree, tvb, offset, 2,
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"Checksum: 0x%04x [correct]",
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cksum);
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} else {
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proto_tree_add_text(carp_tree, tvb, offset, 2,
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"Checksum: 0x%04x [incorrect, should be 0x%04x]",
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cksum,
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in_cksum_shouldbe(cksum, computed_cksum));
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}
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} else {
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proto_tree_add_text(carp_tree, tvb, offset, 2,
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"Checksum: 0x%04x", cksum);
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}
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offset+=2;
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/* Counter */
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proto_tree_add_item(carp_tree, hf_carp_counter, tvb, offset, 8, ENC_BIG_ENDIAN);
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offset+=8;
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proto_tree_add_item(carp_tree, hf_carp_hmac, tvb, offset, 20, ENC_ASCII|ENC_NA);
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offset+=20;
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return offset;
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}
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/* heuristic dissector */
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static gboolean
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dissect_carp_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
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2013-06-14 15:08:10 +00:00
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{
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2013-06-14 14:35:34 +00:00
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if (!test_carp_packet(tvb, pinfo, tree, data))
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return FALSE;
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dissect_carp(tvb, pinfo, tree, data);
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2013-06-14 15:08:10 +00:00
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return TRUE;
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2013-06-14 14:35:34 +00:00
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}
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void proto_register_carp(void)
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{
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static hf_register_info hf[] = {
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{ &hf_carp_ver_type,
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{"CARP message version and type", "carp.typever",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"CARP version and type", HFILL }},
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{ &hf_carp_version,
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{"CARP protocol version", "carp.version",
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FT_UINT8, BASE_DEC, NULL, CARP_VERSION_MASK,
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"CARP version", HFILL }},
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{ &hf_carp_type,
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{"CARP packet type", "carp.type",
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FT_UINT8, BASE_DEC, VALS(carp_type_vals), CARP_TYPE_MASK,
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"CARP type", HFILL }},
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{ &hf_carp_vhid,
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{"Virtual Host ID", "carp.vhid",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_carp_advskew,
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{"Advertisment Skew", "carp.advskew",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_carp_authlen,
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{"Auth Len", "carp.authlen",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"Size of counter+hash in 32bit chunks", HFILL }},
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{ &hf_carp_demotion,
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{"Demotion indicator", "carp.demotion",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_carp_advbase,
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{"Adver Int", "carp.adver_int",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"Time interval (in seconds) between ADVERTISEMENTS", HFILL }},
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{ &hf_carp_counter, {"Counter", "carp.counter",
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FT_UINT64, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_carp_hmac,
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{"HMAC", "carp.hmac",
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FT_BYTES, BASE_NONE, NULL, 0x0,
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"SHA-1 HMAC", HFILL }},
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};
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static gint *ett[] = {
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&ett_carp,
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&ett_carp_ver_type
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};
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proto_carp = proto_register_protocol("Common Address Redundancy Protocol",
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"CARP", "carp");
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proto_register_field_array(proto_carp, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_carp(void)
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{
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dissector_handle_t carp_handle;
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carp_handle = new_create_dissector_handle(dissect_carp, proto_carp);
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dissector_add_uint("ip.proto", IP_PROTO_VRRP, carp_handle);
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heur_dissector_add( "ip", dissect_carp_heur, proto_carp);
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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