2 * Routines for VLAN 802.1Q ethernet header disassembly
4 * Wireshark - Network traffic analyzer
5 * By Gerald Combs <gerald@wireshark.org>
6 * Copyright 1998 Gerald Combs
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version 2
11 * of the License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 #define NEW_PROTO_TREE_API
28 #include <epan/packet.h>
29 #include <wsutil/pint.h>
30 #include <epan/expert.h>
31 #include "packet-ieee8023.h"
32 #include "packet-ipx.h"
33 #include "packet-llc.h"
34 #include "packet-vlan.h"
35 #include <epan/etypes.h>
36 #include <epan/prefs.h>
37 #include <epan/to_str.h>
39 void proto_register_vlan(void);
40 void proto_reg_handoff_vlan(void);
42 static unsigned int q_in_q_ethertype = 0x9100;
44 static gboolean vlan_summary_in_tree = TRUE;
47 static dissector_handle_t vlan_handle;
48 static dissector_handle_t ethertype_handle;
50 static header_field_info *hfi_vlan = NULL;
52 #define VLAN_HFI_INIT HFI_INIT(proto_vlan)
54 /* From Table G-2 of IEEE standard 802.1D-2004 */
55 static const value_string pri_vals[] = {
58 { 0, "Best Effort (default)" },
59 { 3, "Excellent Effort" },
60 { 4, "Controlled Load" },
61 { 5, "Video, < 100ms latency and jitter" },
62 { 6, "Voice, < 10ms latency and jitter" },
63 { 7, "Network Control" },
67 static header_field_info hfi_vlan_priority VLAN_HFI_INIT = {
68 "Priority", "vlan.priority", FT_UINT16, BASE_DEC,
69 VALS(pri_vals), 0xE000, "Descriptions are recommendations from IEEE standard 802.1D-2004", HFILL };
71 static const value_string cfi_vals[] = {
73 { 1, "Non-canonical" },
77 static header_field_info hfi_vlan_cfi VLAN_HFI_INIT = {
78 "CFI", "vlan.cfi", FT_UINT16, BASE_DEC,
79 VALS(cfi_vals), 0x1000, "Canonical Format Identifier", HFILL };
81 static header_field_info hfi_vlan_id VLAN_HFI_INIT = {
82 "ID", "vlan.id", FT_UINT16, BASE_DEC,
83 NULL, 0x0FFF, "VLAN ID", HFILL };
85 static header_field_info hfi_vlan_etype VLAN_HFI_INIT = {
86 "Type", "vlan.etype", FT_UINT16, BASE_HEX,
87 VALS(etype_vals), 0x0, "Ethertype", HFILL };
89 static header_field_info hfi_vlan_len VLAN_HFI_INIT = {
90 "Length", "vlan.len", FT_UINT16, BASE_DEC,
91 NULL, 0x0, NULL, HFILL };
93 static header_field_info hfi_vlan_trailer VLAN_HFI_INIT = {
94 "Trailer", "vlan.trailer", FT_BYTES, BASE_NONE,
95 NULL, 0x0, "VLAN Trailer", HFILL };
98 static gint ett_vlan = -1;
100 static expert_field ei_vlan_len = EI_INIT;
103 capture_vlan(const guchar *pd, int offset, int len, packet_counts *ld ) {
105 if ( !BYTES_ARE_IN_FRAME(offset,len,5) ) {
109 encap_proto = pntoh16( &pd[offset+2] );
110 if ( encap_proto <= IEEE_802_3_MAX_LEN) {
111 if ( pd[offset+4] == 0xff && pd[offset+5] == 0xff ) {
114 capture_llc(pd,offset+4,len,ld);
117 capture_ethertype(encap_proto, pd, offset+4, len, ld);
122 columns_set_vlan(column_info *cinfo, guint16 tci)
124 static const char fast_str[][2] = { "0", "1", "2", "3", "4", "5", "6", "7" };
128 guint32_to_str_buf(tci & 0xFFF, id_str, sizeof(id_str));
130 col_add_lstr(cinfo, COL_INFO,
131 "PRI: ", fast_str[(tci >> 13) & 7], " "
132 "CFI: ", fast_str[(tci >> 12) & 1], " "
134 COL_ADD_LSTR_TERMINATOR);
135 col_add_str(cinfo, COL_8021Q_VLAN_ID, id_str);
139 dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
143 volatile guint16 encap_proto;
144 volatile gboolean is_802_2;
145 proto_tree *volatile vlan_tree;
147 col_set_str(pinfo->cinfo, COL_PROTOCOL, "VLAN");
148 col_clear(pinfo->cinfo, COL_INFO);
150 tci = tvb_get_ntohs( tvb, 0 );
152 columns_set_vlan(pinfo->cinfo, tci);
157 ti = proto_tree_add_item(tree, hfi_vlan, tvb, 0, 4, ENC_NA);
159 if (vlan_summary_in_tree) {
160 proto_item_append_text(ti, ", PRI: %u, CFI: %u, ID: %u",
161 (tci >> 13), ((tci >> 12) & 1), (tci & 0xFFF));
164 vlan_tree = proto_item_add_subtree(ti, ett_vlan);
166 proto_tree_add_item(vlan_tree, &hfi_vlan_priority, tvb, 0, 2, ENC_BIG_ENDIAN);
167 proto_tree_add_item(vlan_tree, &hfi_vlan_cfi, tvb, 0, 2, ENC_BIG_ENDIAN);
168 proto_tree_add_item(vlan_tree, &hfi_vlan_id, tvb, 0, 2, ENC_BIG_ENDIAN);
171 encap_proto = tvb_get_ntohs(tvb, 2);
172 if (encap_proto <= IEEE_802_3_MAX_LEN) {
173 /* Is there an 802.2 layer? I can tell by looking at the first 2
174 bytes after the VLAN header. If they are 0xffff, then what
175 follows the VLAN header is an IPX payload, meaning no 802.2.
176 (IPX/SPX is they only thing that can be contained inside a
177 straight 802.3 packet, so presumably the same applies for
178 Ethernet VLAN packets). A non-0xffff value means that there's an
179 802.2 layer inside the VLAN layer */
182 /* Don't throw an exception for this check (even a BoundsError) */
183 if (tvb_length_remaining(tvb, 4) >= 2) {
184 if (tvb_get_ntohs(tvb, 4) == 0xffff) {
189 dissect_802_3(encap_proto, is_802_2, tvb, 4, pinfo, tree, vlan_tree,
190 hfi_vlan_len.id, hfi_vlan_trailer.id, &ei_vlan_len, 0);
192 ethertype_data_t ethertype_data;
194 ethertype_data.etype = encap_proto;
195 ethertype_data.offset_after_ethertype = 4;
196 ethertype_data.fh_tree = vlan_tree;
197 ethertype_data.etype_id = hfi_vlan_etype.id;
198 ethertype_data.trailer_id = hfi_vlan_trailer.id;
199 ethertype_data.fcs_len = 0;
201 call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, ðertype_data);
206 proto_register_vlan(void)
208 #ifndef HAVE_HFI_SECTION_INIT
209 static header_field_info *hfi[] = {
217 #endif /* HAVE_HFI_SECTION_INIT */
219 static gint *ett[] = {
223 static ei_register_info ei[] = {
224 { &ei_vlan_len, { "vlan.len.past_end", PI_MALFORMED, PI_ERROR, "Length field value goes past the end of the payload", EXPFILL }},
227 module_t *vlan_module;
228 expert_module_t* expert_vlan;
231 proto_vlan = proto_register_protocol("802.1Q Virtual LAN", "VLAN", "vlan");
232 hfi_vlan = proto_registrar_get_nth(proto_vlan);
234 proto_register_fields(proto_vlan, hfi, array_length(hfi));
235 proto_register_subtree_array(ett, array_length(ett));
236 expert_vlan = expert_register_protocol(proto_vlan);
237 expert_register_field_array(expert_vlan, ei, array_length(ei));
239 vlan_module = prefs_register_protocol(proto_vlan, proto_reg_handoff_vlan);
240 prefs_register_bool_preference(vlan_module, "summary_in_tree",
241 "Show vlan summary in protocol tree",
242 "Whether the vlan summary line should be shown in the protocol tree",
243 &vlan_summary_in_tree);
244 prefs_register_uint_preference(vlan_module, "qinq_ethertype",
245 "802.1QinQ Ethertype (in hex)",
246 "The (hexadecimal) Ethertype used to indicate 802.1QinQ VLAN in VLAN tunneling.",
247 16, &q_in_q_ethertype);
249 vlan_handle = create_dissector_handle(dissect_vlan, proto_vlan);
253 proto_reg_handoff_vlan(void)
255 static gboolean prefs_initialized = FALSE;
256 static unsigned int old_q_in_q_ethertype;
258 if (!prefs_initialized)
260 dissector_add_uint("ethertype", ETHERTYPE_VLAN, vlan_handle);
261 prefs_initialized = TRUE;
265 dissector_delete_uint("ethertype", old_q_in_q_ethertype, vlan_handle);
268 old_q_in_q_ethertype = q_in_q_ethertype;
269 ethertype_handle = find_dissector("ethertype");
271 dissector_add_uint("ethertype", q_in_q_ethertype, vlan_handle);