forked from osmocom/wireshark
From report of Alexander Okonnikov and Patch of Matt Texier via https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=8802 Incorrect decoding of Layer2 Info Extended Community
Within BGP Update message for BGP VPLS (RFC 4761) some parts of Extended Community "Layer2 Info" are incorrectly decoded: 1. Encapsulation - Unknown (0x13). Per RFC 4761 encap type 0x13 is "VPLS" (clause 3.2.4); 2. Control Flags - per RFC 4761 (clause 3.2.4) two least-significant bits (6 and 7) are defined as: "C" (bit 6, Control Word): value 1 - Control Word is required - and value 0 - Control Word is not required; decoding is correct (at least for value 0); "S" (bit 7, Sequence delivery): value 1 - Sequence delivery is required - and value 0 - Sequence delivery is not required; decoding is incorrect, because for value 0 (sequence delivery is not required) you provide description that "Sequence delivery is required". Also, there is description (at the same string) "F Flag (reserved) set. IETF document draft-ietf-l2vpn-vpls-multihoming (clause 3.3.1) updates RFC 4761 and defines two additional bits within Control Flags byte - D (bit 0, "Down") and F (bit 2, "Flush"). You provide description that "F Flag (reserved) set" when this flag actually is not set (value 0). Furthermore, you don't provide description about status of flag D (in attached dump in the first packet flag D is set and unset in the second packet). svn path=/trunk/; revision=50085
This commit is contained in:
Alexis La Goutte
parent
0a249bf647
commit
8e4e4a3d76
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@ -261,6 +261,14 @@ void proto_reg_handoff_bgp(void);
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#define BGP_EXT_COM_FSPEC_ACT_S 0x02
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#define BGP_EXT_COM_FSPEC_ACT_T 0x01
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/* extended community l2vpn flags */
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#define BGP_EXT_COM_L2_FLAG_D 0x80
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#define BGP_EXT_COM_L2_FLAG_Z1 0x40
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#define BGP_EXT_COM_L2_FLAG_F 0x20
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#define BGP_EXT_COM_L2_FLAG_Z345 0x1c
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#define BGP_EXT_COM_L2_FLAG_C 0x02
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#define BGP_EXT_COM_L2_FLAG_S 0x01
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/* Extended community QoS Marking technology type */
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#define QOS_TECH_TYPE_DSCP 0x00 /* DiffServ enabled IP (DSCP encoding) */
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@ -542,17 +550,28 @@ static const value_string bgp_ssa_type[] = {
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static const value_string bgp_l2vpn_encaps[] = {
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{ 0, "Reserved"},
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{ 1, "Frame Relay"},
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{ 2, "ATM AAL5 VCC transport"},
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{ 2, "ATM AAL5 SDU VCC transport"},
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{ 3, "ATM transparent cell transport"},
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{ 4, "Ethernet VLAN"},
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{ 5, "Ethernet"},
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{ 4, "Ethernet (VLAN) Tagged mode"},
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{ 5, "Ethernet raw mode"},
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{ 6, "Cisco-HDLC"},
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{ 7, "PPP"},
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{ 8, "CEM"},
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{ 9, "ATM VCC cell transport"},
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{ 10, "ATM VPC cell transport"},
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{ 11, "MPLS"},
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{ 12, "VPLS"},
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{ 8, "SONET/SDH CES"},
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{ 9, "ATM n-to-one VCC cell transport"},
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{ 10, "ATM n-to-one VPC cell transport"},
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{ 11, "IP layer 2 transport"},
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{ 15, "Frame relay port mode"},
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{ 17, "Structure agnostic E1 over packet"},
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{ 18, "Structure agnostic T1 over packet"},
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{ 19, "VPLS"},
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{ 20, "Structure agnostic T3 over packet"},
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{ 21, "Nx64kbit/s Basic Service using Structure-aware"},
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{ 25, "Frame Relay DLCI"},
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{ 40, "Structure agnostic E3 over packet"},
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{ 41, "Octet-aligned playload for structure-agnostic DS1 circuits"},
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{ 42, "E1 Nx64kbit/s with CAS using Structure-aware"},
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{ 43, "DS1 (ESF) Nx64kbit/s with CAS using Structure-aware"},
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{ 44, "DS1 (SF) Nx64kbit/s with CAS using Structure-aware"},
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{ 64, "IP-interworking"},
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{ 0, NULL }
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};
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@ -864,7 +883,15 @@ static int hf_bgp_ext_com_act_samp_act = -1; /* RFC 5575 flow spec action sample
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static int hf_bgp_ext_com_flow_redir_as = -1; /* RFC 5575 AS part of the RT for redirect traffic */
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static int hf_bgp_ext_com_flow_redir_an = -1; /* RFC 5575 AN part of the RT for redirect traffic */
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static int hf_bgp_ext_com_flow_redir = -1;
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static int hf_bgp_ext_com_l2_encaps = -1;
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static int hf_bgp_ext_com_l2_c_flags = -1;
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static int hf_bgp_ext_com_l2_mtu = -1;
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static int hf_bgp_ext_com_l2_flag_d = -1;
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static int hf_bgp_ext_com_l2_flag_z1 = -1;
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static int hf_bgp_ext_com_l2_flag_f = -1;
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static int hf_bgp_ext_com_l2_flag_z345 = -1;
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static int hf_bgp_ext_com_l2_flag_c = -1;
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static int hf_bgp_ext_com_l2_flag_s = -1;
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static gint ett_bgp = -1;
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static gint ett_bgp_prefix = -1;
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@ -892,6 +919,7 @@ static gint ett_bgp_cap = -1; /* an cap parameter tree */
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static gint ett_bgp_extended_communities = -1; /* extended communities list tree */
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static gint ett_bgp_extended_com_fspec_redir = -1; /* extended communities BGP flow act redirect */
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static gint ett_bgp_ext_com_flags = -1; /* extended communities flags tree */
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static gint ett_bgp_ext_com_l2_flags = -1; /* extended commuties tree for l2 services flags */
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static gint ett_bgp_ssa = -1; /* safi specific attribute */
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static gint ett_bgp_ssa_subtree = -1; /* safi specific attribute Subtrees */
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static gint ett_bgp_orf = -1; /* orf (outbound route filter) tree */
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@ -2841,6 +2869,7 @@ dissect_bgp_update(tvbuff_t *tvb, proto_tree *tree, packet_info *pinfo)
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guint16 len; /* tmp */
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int advance; /* tmp */
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proto_item *ti; /* tree item */
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proto_item *sub_ti; /* tree fir sub item */
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proto_tree *subtree; /* subtree for attributes */
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proto_tree *subtree2; /* subtree for attributes */
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proto_tree *subtree3; /* subtree for attributes */
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@ -3773,29 +3802,20 @@ dissect_bgp_update(tvbuff_t *tvb, proto_tree *tree, packet_info *pinfo)
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break;
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case BGP_EXT_COM_L2INFO:
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is_extended_type = TRUE;
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ep_strbuf_append_printf(junk_emstr,
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": %s, Control Flags: %s%s%s%s%s, MTU: %u byte%s",
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val_to_str_const(tvb_get_guint8(tvb,q+2),bgp_l2vpn_encaps,"Unknown"),
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tvb_get_guint8(tvb,q+3) ? "" : "none",
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tvb_get_ntohs(tvb,q+3)&0x08 ? "Q" : "",
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tvb_get_ntohs(tvb,q+3)&0x04 ? "F" : "",
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tvb_get_ntohs(tvb,q+3)&0x02 ? "C" : "",
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tvb_get_ntohs(tvb,q+3)&0x01 ? "S" : "",
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tvb_get_ntohs(tvb,q+4),
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plurality(tvb_get_ntohs(tvb,q+4), "", "s"));
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ti = proto_tree_add_text(subtree3,tvb,q,8, "%s",junk_emstr->str);
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subtree4 = proto_item_add_subtree(ti,ett_bgp_extended_communities);
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proto_tree_add_text(subtree4,tvb,q+2,1, "Encapsulation: %s",
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val_to_str_const(tvb_get_guint8(tvb,q+2),bgp_l2vpn_encaps,"Unknown"));
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proto_tree_add_text(subtree4,tvb,q+3,1, "Control Flags: %s%sControl Word %s required, Sequenced delivery %s required",
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tvb_get_ntohs(tvb,q+3)&0x08 ? "Q flag (Reserved) set" : "",
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tvb_get_ntohs(tvb,q+3)&0x04 ? "F flag (reserved) set" : "",
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tvb_get_ntohs(tvb,q+3)&0x02 ? "is" : "not",
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tvb_get_ntohs(tvb,q+3)&0x01 ? "is" : "not");
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proto_tree_add_text(subtree4,tvb,q+4,2, "MTU: %u byte%s",
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tvb_get_ntohs(tvb,q+4),
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plurality(tvb_get_ntohs(tvb,q+4), "", "s"));
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proto_tree_add_item(subtree4, hf_bgp_ext_com_l2_encaps,tvb,q+2, 1, ENC_BIG_ENDIAN);
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sub_ti = proto_tree_add_item(subtree4, hf_bgp_ext_com_l2_c_flags, tvb, q+3, 1, ENC_BIG_ENDIAN);
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subtree5 = proto_item_add_subtree(sub_ti, ett_bgp_ext_com_l2_flags);
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proto_tree_add_item(subtree5, hf_bgp_ext_com_l2_flag_d, tvb, q+3, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(subtree5, hf_bgp_ext_com_l2_flag_z1, tvb, q+3, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(subtree5, hf_bgp_ext_com_l2_flag_f, tvb, q+3, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(subtree5, hf_bgp_ext_com_l2_flag_z345, tvb, q+3, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(subtree5, hf_bgp_ext_com_l2_flag_c, tvb, q+3, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(subtree5, hf_bgp_ext_com_l2_flag_s, tvb, q+3, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(subtree4, hf_bgp_ext_com_l2_mtu, tvb, q+4, 2, ENC_BIG_ENDIAN);
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break;
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case BGP_EXT_COM_FLOW_ACT:
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is_extended_type = TRUE;
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@ -5006,7 +5026,34 @@ proto_register_bgp(void)
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{ &hf_bgp_ext_com_qos_default_to_zero,
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{ "Defaults to zero", "bgp.ext_com_qos.default_to_zero", FT_UINT8, BASE_HEX,
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NULL, 0, NULL, HFILL}},
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};
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{ &hf_bgp_ext_com_l2_encaps,
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{ "Encaps Type", "bgp.ext_com_l2.encaps_type", FT_UINT8, BASE_DEC,
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VALS(bgp_l2vpn_encaps), 0, NULL, HFILL}},
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{ &hf_bgp_ext_com_l2_c_flags,
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{ "Control Flags", "bgp.ext_com_l2.c_flags", FT_UINT8, BASE_HEX,
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NULL, 0x0, NULL, HFILL }},
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{ &hf_bgp_ext_com_l2_flag_d,
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{ "Down flag", "bgp.ext_com_l2.flag_d",FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), BGP_EXT_COM_L2_FLAG_D, NULL, HFILL }},
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{ &hf_bgp_ext_com_l2_flag_z1,
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{ "Unassigned", "bgp.ext_com_l2.flag_z1",FT_UINT8, BASE_DEC,
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NULL, BGP_EXT_COM_L2_FLAG_Z1, "Must be Zero", HFILL }},
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{ &hf_bgp_ext_com_l2_flag_f,
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{ "Flush flag", "bgp.ext_com_l2.flag_f",FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), BGP_EXT_COM_L2_FLAG_F, NULL, HFILL }},
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{ &hf_bgp_ext_com_l2_flag_z345,
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{ "Unassigned", "bgp.ext_com_l2.flag_z345",FT_UINT8, BASE_DEC,
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NULL, BGP_EXT_COM_L2_FLAG_Z345, "Must be Zero", HFILL }},
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{ &hf_bgp_ext_com_l2_flag_c,
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{ "C flag", "bgp.ext_com_l2.flag_c",FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), BGP_EXT_COM_L2_FLAG_C, NULL, HFILL }},
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{ &hf_bgp_ext_com_l2_flag_s,
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{ "S flag", "bgp.ext_com_l2.flag_s",FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), BGP_EXT_COM_L2_FLAG_S, NULL, HFILL }},
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{ &hf_bgp_ext_com_l2_mtu,
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{ "Layer-2 MTU", "bgp.ext_com_l2.l2_mtu", FT_UINT16, BASE_DEC,
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NULL, 0x0, NULL, HFILL}},
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};
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static gint *ett[] = {
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&ett_bgp,
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@ -5035,6 +5082,7 @@ proto_register_bgp(void)
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&ett_bgp_extended_communities,
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&ett_bgp_extended_com_fspec_redir,
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&ett_bgp_ext_com_flags,
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&ett_bgp_ext_com_l2_flags,
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&ett_bgp_ssa,
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&ett_bgp_ssa_subtree,
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&ett_bgp_orf,
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