forked from osmocom/wireshark
725 lines
24 KiB
C
725 lines
24 KiB
C
/* packet-mpls.c
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* Routines for MPLS data packet disassembly
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* RFC 3032
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*
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* (c) Copyright Ashok Narayanan <ashokn@cisco.com>
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*
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* (c) Copyright 2006, _FF_ Francesco Fondelli <francesco.fondelli@gmail.com>
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* - added MPLS OAM support, ITU-T Y.1711
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* - PW Associated Channel Header dissection as per RFC 4385
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* - PW MPLS Control Word dissection as per RFC 4385
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* - mpls subdissector table indexed by label value
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* - enhanced "what's past last mpls label?" heuristic
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*
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* $Id$
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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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/*
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* NOTES
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*
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* This module defines routines to handle Ethernet-encapsulated MPLS IP packets.
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* It should implement all the functionality in <draft-ietf-mpls-label-encaps-07.txt>
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* Multicast MPLS support is not tested yet
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*/
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/* FF NOTES
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*
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* The OAM patch should dissect OAM pdus as described in ITU-T Y.1711
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/ppptypes.h>
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#include <epan/etypes.h>
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#include <epan/prefs.h>
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#include <epan/ipproto.h>
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#include <epan/addr_resolv.h>
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#include "packet-ppp.h"
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#include "packet-mpls.h"
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static gint proto_mpls = -1;
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static gint proto_pw_ach = -1;
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static gint proto_pw_mcw = -1;
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static gint ett_mpls = -1;
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static gint ett_mpls_pw_ach = -1;
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static gint ett_mpls_pw_mcw = -1;
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static gint ett_mpls_oam = -1;
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const value_string special_labels[] = {
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{LABEL_IP4_EXPLICIT_NULL, "IPv4 Explicit-Null"},
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{LABEL_ROUTER_ALERT, "Router Alert"},
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{LABEL_IP6_EXPLICIT_NULL, "IPv6 Explicit-Null"},
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{LABEL_IMPLICIT_NULL, "Implicit-Null"},
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{LABEL_OAM_ALERT, "OAM Alert"},
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{0, NULL }
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};
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/* MPLS filter values */
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enum mpls_filter_keys {
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/* MPLS encap properties */
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MPLSF_LABEL,
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MPLSF_EXP,
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MPLSF_BOTTOM_OF_STACK,
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MPLSF_TTL,
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MPLSF_MAX
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};
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static int mpls_filter[MPLSF_MAX];
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static int hf_mpls_1st_nibble = -1;
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static int hf_mpls_pw_ach_ver = -1;
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static int hf_mpls_pw_ach_res = -1;
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static int hf_mpls_pw_ach_channel_type = -1;
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static int hf_mpls_pw_mcw_flags = -1;
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static int hf_mpls_pw_mcw_length = -1;
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static int hf_mpls_pw_mcw_sequence_number = -1;
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static int hf_mpls_oam_function_type = -1;
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static int hf_mpls_oam_ttsi = -1;
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static int hf_mpls_oam_frequency = -1;
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static int hf_mpls_oam_defect_type = -1;
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static int hf_mpls_oam_defect_location = -1;
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static int hf_mpls_oam_bip16 = -1;
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static const value_string oam_function_type_vals[] = {
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{0x00, "Reserved"},
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{0x01, "CV (Connectivity Verification)"},
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{0x02, "FDI (Forward Defect Indicator)"},
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{0x03, "BDI (Backward Defect Indicator)"},
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{0x04, "Reserved for Performance packets"},
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{0x05, "Reserved for LB-Req (Loopback Request)"},
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{0x06, "Reserved for LB-Rsp (Loopback Response)"},
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{0x07, "FDD (Fast Failure Detection)"},
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{0, NULL }
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};
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static const value_string oam_frequency_vals[] = {
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{0x00, "Reserved"},
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{0x01, "10 ms"},
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{0x02, "20 ms"},
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{0x03, "50 ms (default value)"},
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{0x04, "100 ms"},
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{0x05, "200 ms"},
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{0x06, "500 ms"},
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/* 7-255 Reserved */
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{0, NULL }
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};
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static const value_string oam_defect_type_vals[] = {
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{0x0000, "Reserved"},
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{0x0101, "dServer"},
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{0x0102, "dPeerME"},
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{0x0201, "dLOCV"},
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{0x0202, "dTTSI_Mismatch"},
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{0x0203, "dTTSI_Mismerge"},
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{0x0204, "dExcess"},
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{0x02FF, "dUnknown"},
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{0xFFFF, "Reserved"},
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{0, NULL }
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};
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static hf_register_info mplsf_info[] = {
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/* MPLS header fields */
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{&mpls_filter[MPLSF_LABEL],
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{"MPLS Label", "mpls.label", FT_UINT32, BASE_DEC, VALS(special_labels), 0x0,
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"", HFILL }},
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{&mpls_filter[MPLSF_EXP],
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{"MPLS Experimental Bits", "mpls.exp", FT_UINT8, BASE_DEC, NULL, 0x0,
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"", HFILL }},
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{&mpls_filter[MPLSF_BOTTOM_OF_STACK],
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{"MPLS Bottom Of Label Stack", "mpls.bottom", FT_UINT8, BASE_DEC, NULL, 0x0,
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"", HFILL }},
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{&mpls_filter[MPLSF_TTL],
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{"MPLS TTL", "mpls.ttl", FT_UINT8, BASE_DEC, NULL, 0x0,
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"", HFILL }},
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/* 1st nibble */
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{&hf_mpls_1st_nibble,
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{"MPLS 1st nibble", "mpls.1st_nibble", FT_UINT8,
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BASE_DEC, NULL, 0x0, "MPLS 1st nibble", HFILL }},
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/* PW Associated Channel Header fields */
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{&hf_mpls_pw_ach_ver,
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{"PW Associated Channel Version", "pwach.ver", FT_UINT8, BASE_DEC,
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NULL, 0x0, "PW Associated Channel Version", HFILL }},
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{&hf_mpls_pw_ach_res,
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{"Reserved", "pwach.res", FT_UINT8, BASE_DEC,
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NULL, 0x0, "Reserved", HFILL }},
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{&hf_mpls_pw_ach_channel_type,
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{"PW Associated Channel Type", "pwach.channel_type", FT_UINT16, BASE_HEX,
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NULL, 0x0, "PW Associated Channel Type", HFILL }},
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/* Generic/Preferred PW MPLS Control Word fields */
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{&hf_mpls_pw_mcw_flags,
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{"Generic/Preferred PW MPLS Control Word Flags", "pwmcw.flags", FT_UINT8,
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BASE_HEX, NULL, 0x0, "Generic/Preferred PW MPLS Control Word Flags",
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HFILL }},
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{&hf_mpls_pw_mcw_length,
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{"Generic/Preferred PW MPLS Control Word Length", "pwmcw.length", FT_UINT8,
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BASE_DEC, NULL, 0x0, "Generic/Preferred PW MPLS Control Word Length",
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HFILL }},
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{&hf_mpls_pw_mcw_sequence_number,
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{"Generic/Preferred PW MPLS Control Word Sequence Number",
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"pwmcw.sequence_number", FT_UINT16, BASE_DEC, NULL, 0x0,
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"Generic/Preferred PW MPLS Control Word Sequence Number", HFILL }},
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/* OAM header fields */
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{&hf_mpls_oam_function_type,
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{"Function Type", "mpls.oam.function_type", FT_UINT8,
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BASE_HEX, VALS(oam_function_type_vals), 0x0, "Function Type codepoint", HFILL }},
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{&hf_mpls_oam_ttsi,
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{"Trail Termination Source Identifier", "mpls.oam.ttsi", FT_UINT32,
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BASE_HEX, NULL, 0x0, "Trail Termination Source Identifier", HFILL }},
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{&hf_mpls_oam_frequency,
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{"Frequency", "mpls.oam.frequency", FT_UINT8,
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BASE_HEX, VALS(oam_frequency_vals), 0x0, "Frequency of probe injection", HFILL }},
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{&hf_mpls_oam_defect_type,
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{"Defect Type", "mpls.oam.defect_type", FT_UINT16,
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BASE_HEX, VALS(oam_defect_type_vals), 0x0, "Defect Type", HFILL }},
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{&hf_mpls_oam_defect_location,
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{"Defect Location (AS)", "mpls.oam.defect_location", FT_UINT32,
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BASE_DEC, NULL, 0x0, "Defect Location", HFILL }},
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{&hf_mpls_oam_bip16,
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{"BIP16", "mpls.oam.bip16", FT_UINT16,
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BASE_HEX, NULL, 0x0, "BIP16", HFILL }},
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};
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static dissector_handle_t ipv4_handle;
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static dissector_handle_t ipv6_handle;
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static dissector_handle_t eth_withoutfcs_handle;
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static dissector_handle_t data_handle;
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static dissector_table_t ppp_subdissector_table;
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static dissector_table_t mpls_subdissector_table;
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/*
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* Given a 4-byte MPLS label starting at offset "offset", in tvbuff "tvb",
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* decode it.
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* Return the label in "label", EXP bits in "exp",
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* bottom_of_stack in "bos", and TTL in "ttl"
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*/
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void decode_mpls_label(tvbuff_t *tvb, int offset,
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guint32 *label, guint8 *exp,
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guint8 *bos, guint8 *ttl)
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{
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guint8 octet0 = tvb_get_guint8(tvb, offset+0);
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guint8 octet1 = tvb_get_guint8(tvb, offset+1);
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guint8 octet2 = tvb_get_guint8(tvb, offset+2);
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*label = (octet0 << 12) + (octet1 << 4) + ((octet2 >> 4) & 0xff);
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*exp = (octet2 >> 1) & 0x7;
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*bos = (octet2 & 0x1);
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*ttl = tvb_get_guint8(tvb, offset+3);
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}
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/*
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* FF: PW Associated Channel Header dissection as per RFC 4385.
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*/
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static void
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dissect_pw_ach(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *mpls_pw_ach_tree = NULL;
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proto_item *ti = NULL;
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tvbuff_t *next_tvb = NULL;
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guint8 ver = 0;
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guint16 res = 0;
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guint16 channel_type = 0;
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if (tvb_reported_length_remaining(tvb, 0) < 4) {
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if (tree)
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proto_tree_add_text(tree, tvb, 0, -1, "Error processing Message");
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return;
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}
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ver = (tvb_get_guint8(tvb, 0) & 0x0F);
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res = tvb_get_guint8(tvb, 1);
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channel_type = tvb_get_ntohs(tvb, 2);
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if (tree) {
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ti = proto_tree_add_item(tree, proto_pw_ach, tvb, 0, 4, FALSE);
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mpls_pw_ach_tree = proto_item_add_subtree(ti, ett_mpls_pw_ach);
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if (mpls_pw_ach_tree == NULL)
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return;
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proto_tree_add_uint_format(mpls_pw_ach_tree, hf_mpls_pw_ach_ver,
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tvb, 0, 1, ver, "Version: %d", ver);
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ti = proto_tree_add_uint_format(mpls_pw_ach_tree, hf_mpls_pw_ach_res,
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tvb, 1, 1, res, "Reserved: 0x%02x", res);
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PROTO_ITEM_SET_HIDDEN(ti);
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if (res != 0)
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proto_tree_add_text(mpls_pw_ach_tree, tvb, 1, 1,
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"Error: this byte is reserved and must be 0");
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proto_tree_add_uint_format(mpls_pw_ach_tree, hf_mpls_pw_ach_channel_type,
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tvb, 2, 2, channel_type,
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"Channel Type: %s (0x%04x)",
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val_to_str(channel_type, ppp_vals, "Unknown"),
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channel_type);
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}
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next_tvb = tvb_new_subset(tvb, 4, -1, -1);
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if (!dissector_try_port(ppp_subdissector_table, channel_type,
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next_tvb, pinfo, tree)) {
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call_dissector(data_handle, next_tvb, pinfo, tree);
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}
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}
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/*
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* FF: Generic/Preferred PW MPLS Control Word dissection as per RFC 4385.
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*/
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static void
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dissect_pw_mcw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *mpls_pw_mcw_tree = NULL;
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proto_item *ti = NULL;
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tvbuff_t *next_tvb = NULL;
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guint8 flags = 0;
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guint8 frg = 0;
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guint8 length = 0;
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guint16 sequence_number = 0;
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if (tvb_reported_length_remaining(tvb, 0) < 4) {
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if (tree)
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proto_tree_add_text(tree, tvb, 0, -1, "Error processing Message");
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return;
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}
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/* bits 4 to 7 and FRG bits are displayed together */
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flags = (tvb_get_guint8(tvb, 0) & 0x0F) << 2;
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frg = (tvb_get_guint8(tvb, 1) & 0xC0) >> 6;
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flags |= frg;
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length = tvb_get_guint8(tvb, 1) & 0x3F;
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sequence_number = tvb_get_ntohs(tvb, 2);
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if (tree) {
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ti = proto_tree_add_item(tree, proto_pw_mcw, tvb, 0, 4, FALSE);
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mpls_pw_mcw_tree = proto_item_add_subtree(ti, ett_mpls_pw_mcw);
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if (mpls_pw_mcw_tree == NULL)
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return;
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proto_tree_add_uint_format(mpls_pw_mcw_tree, hf_mpls_pw_mcw_flags,
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tvb, 0, 1, flags, "Flags: 0x%02x", flags);
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ti = proto_tree_add_uint_format(mpls_pw_mcw_tree, hf_mpls_pw_mcw_length,
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tvb, 1, 1, length, "Length: %u", length);
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proto_tree_add_uint_format(mpls_pw_mcw_tree, hf_mpls_pw_mcw_sequence_number,
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tvb, 2, 2, sequence_number,
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"Sequence Number: %d", sequence_number);
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}
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next_tvb = tvb_new_subset(tvb, 4, -1, -1);
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call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
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}
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static void
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dissect_mpls_oam_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_tree *mpls_tree,
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int offset, guint8 exp, guint8 bos, guint8 ttl)
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{
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proto_tree *mpls_oam_tree = NULL;
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proto_item *ti = NULL;
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int functype = -1;
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const guint8 allone[] = { 0xff, 0xff };
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const guint8 allzero[] = { 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00 };
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/* if called with main tree == null just set col info with func type string and return */
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if (!tree) {
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if (check_col(pinfo->cinfo, COL_INFO)) {
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if (tvb_bytes_exist(tvb, offset, 1)) {
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functype = tvb_get_guint8(tvb, offset);
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col_append_fstr(pinfo->cinfo, COL_INFO, " (OAM: %s)",
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(functype == 0x01) ? "CV" :
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(functype == 0x02) ? "FDI" :
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(functype == 0x03) ? "BDI" :
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(functype == 0x07) ? "FDD" : "reserved/unknown");
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}
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}
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return;
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}
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/* sanity checks */
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if (!mpls_tree)
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return;
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if (!tvb_bytes_exist(tvb, offset, 44)) {
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/* ITU-T Y.1711, 5.3: OAM pdus must have a minimum payload length of 44 bytes */
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proto_tree_add_text(mpls_tree, tvb, offset, -1, "Error: must have a minimum payload length of 44 bytes");
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return;
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}
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ti = proto_tree_add_text(mpls_tree, tvb, offset, 44, "MPLS Operation & Maintenance");
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mpls_oam_tree = proto_item_add_subtree(ti, ett_mpls_oam);
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if (!mpls_oam_tree)
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return;
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/* checks for exp, bos and ttl encoding */
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if (exp!=0)
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proto_tree_add_text(mpls_oam_tree, tvb, offset - 2, 1, "Warning: Exp bits should be 0 for OAM");
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if (bos!=1)
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proto_tree_add_text(mpls_oam_tree, tvb, offset - 2, 1, "Warning: S bit should be 1 for OAM");
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if (ttl!=1)
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proto_tree_add_text(mpls_oam_tree, tvb, offset - 1, 1, "Warning: TTL should be 1 for OAM");
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/* starting dissection */
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functype = tvb_get_guint8(tvb, offset);
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proto_tree_add_item(mpls_oam_tree, hf_mpls_oam_function_type, tvb, offset, 1, TRUE);
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offset++;
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switch(functype) {
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case 0x01: /* CV */
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{
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guint32 lsrid_ipv4addr;
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/* 3 octets reserved (all 0x00) */
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if (tvb_memeql(tvb, offset, allzero, 3) == -1) {
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proto_tree_add_text(mpls_oam_tree, tvb, offset, 3,
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"Error: these bytes are reserved and must be 0x00");
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}
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offset+=3;
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/* ttsi (ipv4 flavor as in RFC 2373) */
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if (tvb_memeql(tvb, offset, allzero, 10) == -1) {
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proto_tree_add_text(mpls_oam_tree, tvb, offset, 10,
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"Error: these bytes are padding and must be 0x00");
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}
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offset+=10;
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if (tvb_memeql(tvb, offset, allone, 2) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 2,
|
|
"Error: these bytes are padding and must be 0xFF");
|
|
}
|
|
offset+=2;
|
|
|
|
lsrid_ipv4addr = tvb_get_ipv4(tvb, offset);
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 4, "LSR ID: %s", ip_to_str((guint8 *)&lsrid_ipv4addr));
|
|
offset+=4;
|
|
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 4, "LSP ID: %d", tvb_get_ntohl(tvb, offset));
|
|
offset+=4;
|
|
|
|
/* 18 octets of padding (all 0x00) */
|
|
if (tvb_memeql(tvb, offset, allzero, 18) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 18,
|
|
"Error: these bytes are padding and must be 0x00");
|
|
}
|
|
offset+=18;
|
|
}
|
|
break;
|
|
|
|
case 0x02: /* FDI */
|
|
case 0x03: /* BDI */
|
|
{
|
|
guint32 lsrid_ipv4addr;
|
|
|
|
/* 1 octets reserved (all 0x00) */
|
|
if (tvb_memeql(tvb, offset, allzero, 1) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 3,
|
|
"Error: this byte is reserved and must be 0x00");
|
|
}
|
|
offset++;
|
|
|
|
proto_tree_add_item(mpls_oam_tree, hf_mpls_oam_defect_type, tvb, offset, 2, TRUE);
|
|
offset+=2;
|
|
|
|
/* ttsi (ipv4 flavor as in RFC 2373) is optional if not used must be set to all 0x00 */
|
|
if (tvb_memeql(tvb, offset, allzero, 20) == 0) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 20, "TTSI not preset (optional for FDI/BDI)");
|
|
offset+=20;
|
|
} else {
|
|
if (tvb_memeql(tvb, offset, allzero, 10) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 10,
|
|
"Error: these bytes are padding and must be 0x00");
|
|
}
|
|
offset+=10;
|
|
|
|
if (tvb_memeql(tvb, offset, allone, 2) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 2,
|
|
"Error: these bytes are padding and must be 0xFF");
|
|
}
|
|
offset+=2;
|
|
|
|
lsrid_ipv4addr = tvb_get_ipv4(tvb, offset);
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 4, "LSR ID: %s", ip_to_str((guint8 *)&lsrid_ipv4addr));
|
|
offset+=4;
|
|
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 4, "LSP ID: %d", tvb_get_ntohl(tvb, offset));
|
|
offset+=4;
|
|
}
|
|
|
|
/* defect location */
|
|
proto_tree_add_item(mpls_oam_tree, hf_mpls_oam_defect_location, tvb, offset, 4, TRUE);
|
|
offset+=4;
|
|
|
|
/* 14 octets of padding (all 0x00) */
|
|
if (tvb_memeql(tvb, offset, allzero, 14) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 14,
|
|
"Error: these bytes are padding and must be 0x00");
|
|
}
|
|
offset+=14;
|
|
}
|
|
break;
|
|
|
|
case 0x07: /* FDD */
|
|
{
|
|
guint32 lsrid_ipv4addr;
|
|
|
|
/* 3 octets reserved (all 0x00) */
|
|
if (tvb_memeql(tvb, offset, allzero, 3) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 3,
|
|
"Error: these bytes are reserved and must be 0x00");
|
|
}
|
|
offset+=3;
|
|
|
|
/* ttsi (ipv4 flavor as in RFC 2373) */
|
|
if (tvb_memeql(tvb, offset, allzero, 10) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 10,
|
|
"Error: these bytes are padding and must be 0x00");
|
|
}
|
|
offset+=10;
|
|
|
|
if (tvb_memeql(tvb, offset, allone, 2) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 2,
|
|
"Error: these bytes are padding and must be 0xFF");
|
|
}
|
|
offset+=2;
|
|
|
|
lsrid_ipv4addr = tvb_get_ipv4(tvb, offset);
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 4, "LSR ID: %s", ip_to_str((guint8 *)&lsrid_ipv4addr));
|
|
offset+=4;
|
|
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 4, "LSP ID: %d", tvb_get_ntohl(tvb, offset));
|
|
offset+=4;
|
|
|
|
proto_tree_add_item(mpls_oam_tree, hf_mpls_oam_frequency, tvb, offset, 1, TRUE);
|
|
offset++;
|
|
|
|
/* 17 octets of padding (all 0x00) */
|
|
if (tvb_memeql(tvb, offset, allzero, 17) == -1) {
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset, 17,
|
|
"Error: these bytes are padding and must be 0x00");
|
|
}
|
|
offset+=17;
|
|
}
|
|
break;
|
|
|
|
default:
|
|
proto_tree_add_text(mpls_oam_tree, tvb, offset - 1, -1, "Unknown MPLS OAM pdu");
|
|
return;
|
|
}
|
|
|
|
/* BIP16 */
|
|
proto_tree_add_item(mpls_oam_tree, hf_mpls_oam_bip16, tvb, offset, 2, TRUE);
|
|
offset+=2;
|
|
}
|
|
|
|
/*
|
|
* FF: this function returns TRUE if the first 12 bytes in tvb looks like
|
|
* two valid ethernet addresses. FALSE otherwise.
|
|
*/
|
|
static gboolean
|
|
looks_like_plain_eth(tvbuff_t *tvb _U_)
|
|
{
|
|
const gchar *manuf_name_da = NULL;
|
|
const gchar *manuf_name_sa = NULL;
|
|
|
|
if (tvb_reported_length_remaining(tvb, 0) < 14) {
|
|
return FALSE;
|
|
}
|
|
|
|
manuf_name_da = get_manuf_name_if_known(tvb_get_ptr(tvb, 0, 6));
|
|
manuf_name_sa = get_manuf_name_if_known(tvb_get_ptr(tvb, 6, 6));
|
|
|
|
if (manuf_name_da && manuf_name_sa) {
|
|
return TRUE;
|
|
}
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
static void
|
|
dissect_mpls(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
|
|
{
|
|
int offset = 0;
|
|
guint32 label = LABEL_INVALID;
|
|
guint8 exp;
|
|
guint8 bos;
|
|
guint8 ttl;
|
|
guint8 nibble;
|
|
|
|
proto_tree *mpls_tree = NULL;
|
|
proto_item *ti;
|
|
tvbuff_t *next_tvb;
|
|
|
|
if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
|
|
col_set_str(pinfo->cinfo,COL_PROTOCOL, "MPLS");
|
|
}
|
|
|
|
if (check_col(pinfo->cinfo,COL_INFO)) {
|
|
col_set_str(pinfo->cinfo,COL_INFO,"MPLS Label Switched Packet");
|
|
}
|
|
|
|
/* Start Decoding Here. */
|
|
while (tvb_reported_length_remaining(tvb, offset) > 0) {
|
|
|
|
decode_mpls_label(tvb, offset, &label, &exp, &bos, &ttl);
|
|
pinfo->mpls_label = label;
|
|
|
|
if (tree) {
|
|
|
|
ti = proto_tree_add_item(tree, proto_mpls, tvb, offset, 4, FALSE);
|
|
mpls_tree = proto_item_add_subtree(ti, ett_mpls);
|
|
|
|
proto_item_append_text(ti, ", Label: %u", label);
|
|
if (label <= LABEL_MAX_RESERVED){
|
|
proto_tree_add_uint_format(mpls_tree, mpls_filter[MPLSF_LABEL], tvb,
|
|
offset, 3, label, "MPLS Label: %u (%s)",
|
|
label, val_to_str(label, special_labels,
|
|
"Reserved - Unknown"));
|
|
proto_item_append_text(ti, " (%s)", val_to_str(label, special_labels,
|
|
"Reserved - Unknown"));
|
|
} else {
|
|
proto_tree_add_uint_format(mpls_tree, mpls_filter[MPLSF_LABEL], tvb,
|
|
offset, 3, label, "MPLS Label: %u", label);
|
|
}
|
|
|
|
proto_tree_add_uint(mpls_tree,mpls_filter[MPLSF_EXP], tvb,
|
|
offset+2,1, exp);
|
|
proto_item_append_text(ti, ", Exp: %u", exp);
|
|
|
|
proto_tree_add_uint(mpls_tree,mpls_filter[MPLSF_BOTTOM_OF_STACK], tvb,
|
|
offset+2,1, bos);
|
|
proto_item_append_text(ti, ", S: %u", bos);
|
|
|
|
proto_tree_add_uint(mpls_tree,mpls_filter[MPLSF_TTL], tvb,
|
|
offset+3,1, ttl);
|
|
proto_item_append_text(ti, ", TTL: %u", ttl);
|
|
}
|
|
|
|
if (label == LABEL_OAM_ALERT) {
|
|
/* OAM pdus are injected in normal data plane flow in order to test a LSP,
|
|
* they carry no user data.
|
|
*/
|
|
dissect_mpls_oam_pdu(tvb, pinfo, tree, mpls_tree, offset + 4, exp, bos, ttl);
|
|
return;
|
|
}
|
|
|
|
offset += 4;
|
|
if (bos) break;
|
|
}
|
|
|
|
nibble = (tvb_get_guint8(tvb, offset) >> 4) & 0x0F;
|
|
ti = proto_tree_add_uint(mpls_tree, hf_mpls_1st_nibble, tvb, offset, 1, nibble);
|
|
PROTO_ITEM_SET_HIDDEN(ti);
|
|
|
|
next_tvb = tvb_new_subset(tvb, offset, -1, -1);
|
|
|
|
if (!dissector_try_port(mpls_subdissector_table, label,
|
|
next_tvb, pinfo, tree)) {
|
|
if (nibble == 6) {
|
|
call_dissector(ipv6_handle, next_tvb, pinfo, tree);
|
|
} else if (nibble == 4) {
|
|
call_dissector(ipv4_handle, next_tvb, pinfo, tree);
|
|
} else if (nibble == 1) {
|
|
dissect_pw_ach(next_tvb, pinfo, tree);
|
|
} else if (nibble == 0) {
|
|
if (looks_like_plain_eth(next_tvb)) {
|
|
call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
|
|
} else {
|
|
dissect_pw_mcw(next_tvb, pinfo, tree);
|
|
}
|
|
} else {
|
|
/*
|
|
* FF: no external hint, 1st nibble is not 6, 4, 1 or 0...
|
|
* good luck!
|
|
*/
|
|
call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
proto_register_mpls(void)
|
|
{
|
|
static gint *ett[] = {
|
|
&ett_mpls,
|
|
&ett_mpls_pw_ach,
|
|
&ett_mpls_pw_mcw,
|
|
&ett_mpls_oam,
|
|
};
|
|
|
|
/* FF: mpls subdissector table is indexed by label */
|
|
mpls_subdissector_table = register_dissector_table("mpls.label",
|
|
"MPLS protocol",
|
|
FT_UINT32, BASE_DEC);
|
|
proto_mpls = proto_register_protocol("MultiProtocol Label Switching Header",
|
|
"MPLS", "mpls");
|
|
proto_pw_ach = proto_register_protocol("PW Associated Channel Header",
|
|
"PWACH", "pwach");
|
|
proto_pw_mcw = proto_register_protocol("PW MPLS Control Word (generic/preferred)",
|
|
"PWMCW", "pwmcw");
|
|
proto_register_field_array(proto_mpls, mplsf_info, array_length(mplsf_info));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
register_dissector("mpls", dissect_mpls, proto_mpls);
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_mpls(void)
|
|
{
|
|
dissector_handle_t mpls_handle;
|
|
|
|
/*
|
|
* Get a handle for the IPv4 and IPv6 dissectors and PPP protocol dissector table.
|
|
*/
|
|
ipv4_handle = find_dissector("ip");
|
|
ipv6_handle = find_dissector("ipv6");
|
|
eth_withoutfcs_handle = find_dissector("eth_withoutfcs");
|
|
data_handle = find_dissector("data");
|
|
ppp_subdissector_table = find_dissector_table("ppp.protocol");
|
|
|
|
mpls_handle = find_dissector("mpls");
|
|
dissector_add("ethertype", ETHERTYPE_MPLS, mpls_handle);
|
|
dissector_add("ethertype", ETHERTYPE_MPLS_MULTI, mpls_handle);
|
|
dissector_add("ppp.protocol", PPP_MPLS_UNI, mpls_handle);
|
|
dissector_add("ppp.protocol", PPP_MPLS_MULTI, mpls_handle);
|
|
dissector_add("chdlctype", ETHERTYPE_MPLS, mpls_handle);
|
|
dissector_add("chdlctype", ETHERTYPE_MPLS_MULTI, mpls_handle);
|
|
dissector_add("gre.proto", ETHERTYPE_MPLS, mpls_handle);
|
|
dissector_add("gre.proto", ETHERTYPE_MPLS_MULTI, mpls_handle);
|
|
dissector_add("ip.proto", IP_PROTO_MPLS_IN_IP, mpls_handle);
|
|
}
|