2 * Routines for VLAN 802.1Q ethernet header disassembly
6 * Wireshark - Network traffic analyzer
7 * By Gerald Combs <gerald@wireshark.org>
8 * Copyright 1998 Gerald Combs
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
25 #define NEW_PROTO_TREE_API
30 #include <epan/packet.h>
31 #include <wsutil/pint.h>
32 #include <epan/expert.h>
33 #include "packet-ieee8023.h"
34 #include "packet-ipx.h"
35 #include "packet-llc.h"
36 #include "packet-vlan.h"
37 #include <epan/etypes.h>
38 #include <epan/prefs.h>
40 void proto_reg_handoff_vlan(void);
41 void proto_reg_handoff_vlan(void);
43 static unsigned int q_in_q_ethertype = 0x9100;
45 static gboolean vlan_summary_in_tree = TRUE;
48 static dissector_handle_t vlan_handle;
49 static dissector_handle_t ethertype_handle;
51 static header_field_info *hfi_vlan = NULL;
53 #define VLAN_HFI_INIT HFI_INIT(proto_vlan)
55 /* From Table G-2 of IEEE standard 802.1D-2004 */
56 static const value_string pri_vals[] = {
59 { 0, "Best Effort (default)" },
60 { 3, "Excellent Effort" },
61 { 4, "Controlled Load" },
62 { 5, "Video, < 100ms latency and jitter" },
63 { 6, "Voice, < 10ms latency and jitter" },
64 { 7, "Network Control" },
68 static header_field_info hfi_vlan_priority VLAN_HFI_INIT = {
69 "Priority", "vlan.priority", FT_UINT16, BASE_DEC,
70 VALS(pri_vals), 0xE000, "Descriptions are recommendations from IEEE standard 802.1D-2004", HFILL };
72 static const value_string cfi_vals[] = {
74 { 1, "Non-canonical" },
78 static header_field_info hfi_vlan_cfi VLAN_HFI_INIT = {
79 "CFI", "vlan.cfi", FT_UINT16, BASE_DEC,
80 VALS(cfi_vals), 0x1000, "Canonical Format Identifier", HFILL };
82 static header_field_info hfi_vlan_id VLAN_HFI_INIT = {
83 "ID", "vlan.id", FT_UINT16, BASE_DEC,
84 NULL, 0x0FFF, "VLAN ID", HFILL };
86 static header_field_info hfi_vlan_etype VLAN_HFI_INIT = {
87 "Type", "vlan.etype", FT_UINT16, BASE_HEX,
88 VALS(etype_vals), 0x0, "Ethertype", HFILL };
90 static header_field_info hfi_vlan_len VLAN_HFI_INIT = {
91 "Length", "vlan.len", FT_UINT16, BASE_DEC,
92 NULL, 0x0, NULL, HFILL };
94 static header_field_info hfi_vlan_trailer VLAN_HFI_INIT = {
95 "Trailer", "vlan.trailer", FT_BYTES, BASE_NONE,
96 NULL, 0x0, "VLAN Trailer", HFILL };
99 static gint ett_vlan = -1;
101 static expert_field ei_vlan_len = EI_INIT;
104 capture_vlan(const guchar *pd, int offset, int len, packet_counts *ld ) {
106 if ( !BYTES_ARE_IN_FRAME(offset,len,5) ) {
110 encap_proto = pntoh16( &pd[offset+2] );
111 if ( encap_proto <= IEEE_802_3_MAX_LEN) {
112 if ( pd[offset+4] == 0xff && pd[offset+5] == 0xff ) {
115 capture_llc(pd,offset+4,len,ld);
118 capture_ethertype(encap_proto, pd, offset+4, len, ld);
123 dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
127 volatile guint16 encap_proto;
128 volatile gboolean is_802_2;
129 proto_tree *volatile vlan_tree;
131 col_set_str(pinfo->cinfo, COL_PROTOCOL, "VLAN");
132 col_clear(pinfo->cinfo, COL_INFO);
134 tci = tvb_get_ntohs( tvb, 0 );
136 col_add_fstr(pinfo->cinfo, COL_INFO, "PRI: %u CFI: %u ID: %u",
137 (tci >> 13), ((tci >> 12) & 1), (tci & 0xFFF));
138 col_add_fstr(pinfo->cinfo, COL_8021Q_VLAN_ID, "%u", (tci & 0xFFF));
143 ti = proto_tree_add_item(tree, hfi_vlan, tvb, 0, 4, ENC_NA);
145 if (vlan_summary_in_tree) {
146 proto_item_append_text(ti, ", PRI: %u, CFI: %u, ID: %u",
147 (tci >> 13), ((tci >> 12) & 1), (tci & 0xFFF));
150 vlan_tree = proto_item_add_subtree(ti, ett_vlan);
152 proto_tree_add_item(vlan_tree, &hfi_vlan_priority, tvb, 0, 2, ENC_BIG_ENDIAN);
153 proto_tree_add_item(vlan_tree, &hfi_vlan_cfi, tvb, 0, 2, ENC_BIG_ENDIAN);
154 proto_tree_add_item(vlan_tree, &hfi_vlan_id, tvb, 0, 2, ENC_BIG_ENDIAN);
157 encap_proto = tvb_get_ntohs(tvb, 2);
158 if (encap_proto <= IEEE_802_3_MAX_LEN) {
159 /* Is there an 802.2 layer? I can tell by looking at the first 2
160 bytes after the VLAN header. If they are 0xffff, then what
161 follows the VLAN header is an IPX payload, meaning no 802.2.
162 (IPX/SPX is they only thing that can be contained inside a
163 straight 802.3 packet, so presumably the same applies for
164 Ethernet VLAN packets). A non-0xffff value means that there's an
165 802.2 layer inside the VLAN layer */
168 /* Don't throw an exception for this check (even a BoundsError) */
169 if (tvb_length_remaining(tvb, 4) >= 2) {
170 if (tvb_get_ntohs(tvb, 4) == 0xffff) {
175 dissect_802_3(encap_proto, is_802_2, tvb, 4, pinfo, tree, vlan_tree,
176 hfi_vlan_len.id, hfi_vlan_trailer.id, &ei_vlan_len, 0);
178 ethertype_data_t ethertype_data;
180 ethertype_data.etype = encap_proto;
181 ethertype_data.offset_after_ethertype = 4;
182 ethertype_data.fh_tree = vlan_tree;
183 ethertype_data.etype_id = hfi_vlan_etype.id;
184 ethertype_data.trailer_id = hfi_vlan_trailer.id;
185 ethertype_data.fcs_len = 0;
187 call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, ðertype_data);
192 proto_register_vlan(void)
194 #ifndef HAVE_HFI_SECTION_INIT
195 static header_field_info *hfi[] = {
203 #endif /* HAVE_HFI_SECTION_INIT */
205 static gint *ett[] = {
209 static ei_register_info ei[] = {
210 { &ei_vlan_len, { "vlan.len.past_end", PI_MALFORMED, PI_ERROR, "Length field value goes past the end of the payload", EXPFILL }},
213 module_t *vlan_module;
214 expert_module_t* expert_vlan;
217 proto_vlan = proto_register_protocol("802.1Q Virtual LAN", "VLAN", "vlan");
218 hfi_vlan = proto_registrar_get_nth(proto_vlan);
220 proto_register_fields(proto_vlan, hfi, array_length(hfi));
221 proto_register_subtree_array(ett, array_length(ett));
222 expert_vlan = expert_register_protocol(proto_vlan);
223 expert_register_field_array(expert_vlan, ei, array_length(ei));
225 vlan_module = prefs_register_protocol(proto_vlan, proto_reg_handoff_vlan);
226 prefs_register_bool_preference(vlan_module, "summary_in_tree",
227 "Show vlan summary in protocol tree",
228 "Whether the vlan summary line should be shown in the protocol tree",
229 &vlan_summary_in_tree);
230 prefs_register_uint_preference(vlan_module, "qinq_ethertype",
231 "802.1QinQ Ethertype (in hex)",
232 "The (hexadecimal) Ethertype used to indicate 802.1QinQ VLAN in VLAN tunneling.",
233 16, &q_in_q_ethertype);
235 vlan_handle = create_dissector_handle(dissect_vlan, proto_vlan);
239 proto_reg_handoff_vlan(void)
241 static gboolean prefs_initialized = FALSE;
242 static unsigned int old_q_in_q_ethertype;
244 if (!prefs_initialized)
246 dissector_add_uint("ethertype", ETHERTYPE_VLAN, vlan_handle);
247 prefs_initialized = TRUE;
251 dissector_delete_uint("ethertype", old_q_in_q_ethertype, vlan_handle);
254 old_q_in_q_ethertype = q_in_q_ethertype;
255 ethertype_handle = find_dissector("ethertype");
257 dissector_add_uint("ethertype", q_in_q_ethertype, vlan_handle);