1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
|
/* packet-erspan.c
* Routines for the disassembly of Cisco's ERSPAN protocol
*
* Copyright 2005 Joerg Mayer (see AUTHORS file)
* Updates for newer versions by Jason Masker <jason at masker.net>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* TODO:
* Find out the Unknown values
*
* Specs:
* No real specs exist. Some general description can be found at:
* http://www.cisco.com/en/US/products/hw/routers/ps368/products_configuration_guide_chapter09186a008069952a.html
*
* Some information on ERSPAN type III can be found at:
* http://www.cisco.com/en/US/docs/switches/datacenter/nexus1000/sw/4_0_4_s_v_1_3/system_management/configuration/guide/n1000v_system_9span.html
*
* For ERSPAN packets, the "protocol type" field value in the GRE header
* is 0x88BE (version 1) or 0x22EB (version 2).
*
* ERSPAN type II is version 1
* ERSPAN type III is version 2
*
* 0000000: d4c3 b2a1 0200 0400 0000 0000 0000 0000 <-- pcap header
* 0000010: ffff 0000
* 0000010: 7100 0000 <-- 0x71 (DLT_TYPE) = linux_cooked_capture (of course not)
* 0000010: 7507 f845 11d1 0500 <-- pcap record header
* 0000020: 7a00 0000 7a00 0000
* 0000020: 0000 030a 0000 0000 <-- unknown
* 0000030: 0000 0000
* 0000030: 0000 88be <-- GRE header (version 1)
* 0000030: 1002 0001 0000 0380 <-- ERSPAN header (01: erspan-id)
* 0000040: 00d0 b7a7 7480 0015 c721 75c0 0800 4500 <-- Ethernet packet
* ...
*
*
*/
#include "config.h"
#include <glib.h>
#include <epan/packet.h>
#include <epan/greproto.h>
#include <epan/prefs.h>
#include <epan/expert.h>
void proto_register_erspan(void);
void proto_reg_handoff_erspan(void);
static int proto_erspan = -1;
static gint ett_erspan = -1;
static int hf_erspan_version = -1;
static int hf_erspan_vlan = -1;
static int hf_erspan_priority = -1;
static int hf_erspan_unknown2 = -1;
static int hf_erspan_direction = -1;
static int hf_erspan_unknown3 = -1;
static int hf_erspan_truncated = -1;
static int hf_erspan_spanid = -1;
static int hf_erspan_timestamp = -1;
static int hf_erspan_unknown4 = -1;
static int hf_erspan_direction2 = -1;
static int hf_erspan_unknown5 = -1;
static int hf_erspan_unknown6 = -1;
static int hf_erspan_unknown7 = -1;
static expert_field ei_erspan_version_unknown = EI_INIT;
#define PROTO_SHORT_NAME "ERSPAN"
#define PROTO_LONG_NAME "Encapsulated Remote Switch Packet ANalysis"
/* Global ERSPAN Preference */
static gboolean pref_fake_erspan = FALSE;
#define ERSPAN_DIRECTION_INCOMING 0
#define ERSPAN_DIRECTION_OUTGOING 1
static const value_string erspan_direction_vals[] = {
{ERSPAN_DIRECTION_INCOMING, "Incoming"},
{ERSPAN_DIRECTION_OUTGOING, "Outgoing"},
{0, NULL},
};
static const value_string erspan_truncated_vals[] = {
{0, "Not truncated"},
{1, "Truncated"},
{0, NULL},
};
static const value_string erspan_version_vals[] = {
{1, "Type II"},
{2, "Type III"},
{0, NULL},
};
static dissector_handle_t ethnofcs_handle;
static void
erspan_fmt_timestamp(gchar *result, guint32 timeval)
{
g_snprintf(result, ITEM_LABEL_LENGTH, "%.4f", (((gfloat)timeval)/10000));
}
static void
dissect_erspan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *ti;
proto_item *ti_ver;
proto_tree *erspan_tree = NULL;
tvbuff_t *eth_tvb;
guint32 offset = 0;
guint16 version;
col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_SHORT_NAME);
col_set_str(pinfo->cinfo, COL_INFO, PROTO_SHORT_NAME ":");
if (tree) {
ti = proto_tree_add_item(tree, proto_erspan, tvb, offset, -1,
ENC_NA);
erspan_tree = proto_item_add_subtree(ti, ett_erspan);
}
if(pref_fake_erspan) {
/* Some vendor don't include ERSPAN Header...*/
eth_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(ethnofcs_handle, eth_tvb, pinfo, tree);
return;
}
version = tvb_get_ntohs(tvb, offset) >> 12;
if (tree) {
ti_ver = proto_tree_add_item(erspan_tree, hf_erspan_version, tvb, offset, 2,
ENC_BIG_ENDIAN);
if ((version != 1) && (version != 2 )) {
expert_add_info(pinfo, ti_ver, &ei_erspan_version_unknown);
return;
}
proto_tree_add_item(erspan_tree, hf_erspan_vlan, tvb, offset, 2,
ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(erspan_tree, hf_erspan_priority, tvb, offset, 2,
ENC_BIG_ENDIAN);
proto_tree_add_item(erspan_tree, hf_erspan_unknown2, tvb, offset, 2,
ENC_BIG_ENDIAN);
if (version == 1)
proto_tree_add_item(erspan_tree, hf_erspan_direction, tvb,
offset, 2, ENC_BIG_ENDIAN);
else /* version = 2 */
proto_tree_add_item(erspan_tree, hf_erspan_unknown3, tvb,
offset, 2, ENC_BIG_ENDIAN);
proto_tree_add_item(erspan_tree, hf_erspan_truncated, tvb, offset, 2,
ENC_BIG_ENDIAN);
proto_tree_add_item(erspan_tree, hf_erspan_spanid, tvb, offset, 2,
ENC_BIG_ENDIAN);
offset += 2;
if (version == 2) {
proto_tree_add_item(erspan_tree, hf_erspan_timestamp, tvb,
offset, 4, ENC_BIG_ENDIAN);
offset += 4;
proto_tree_add_item(erspan_tree, hf_erspan_unknown4, tvb,
offset, 2, ENC_NA);
offset += 2;
proto_tree_add_item(erspan_tree, hf_erspan_direction2, tvb,
offset, 2, ENC_BIG_ENDIAN);
proto_tree_add_item(erspan_tree, hf_erspan_unknown5, tvb,
offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(erspan_tree, hf_erspan_unknown6, tvb,
offset, 4, ENC_NA);
offset += 4;
}
proto_tree_add_item(erspan_tree, hf_erspan_unknown7, tvb, offset, 4,
ENC_NA);
offset += 4;
}
else {
offset += 8;
if (version == 2)
offset += 12;
}
eth_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(ethnofcs_handle, eth_tvb, pinfo, tree);
}
void
proto_register_erspan(void)
{
module_t *erspan_module;
expert_module_t* expert_erspan;
static hf_register_info hf[] = {
{ &hf_erspan_version,
{ "Version", "erspan.version", FT_UINT16, BASE_DEC, VALS(erspan_version_vals),
0xf000, NULL, HFILL }},
{ &hf_erspan_vlan,
{ "Vlan", "erspan.vlan", FT_UINT16, BASE_DEC, NULL,
0x0fff, NULL, HFILL }},
{ &hf_erspan_priority,
{ "Priority", "erspan.priority", FT_UINT16, BASE_DEC, NULL,
0xe000, NULL, HFILL }},
{ &hf_erspan_unknown2,
{ "Unknown2", "erspan.unknown2", FT_UINT16, BASE_DEC, NULL,
0x1000, NULL, HFILL }},
{ &hf_erspan_direction,
{ "Direction", "erspan.direction", FT_UINT16, BASE_DEC, VALS(erspan_direction_vals),
0x0800, NULL, HFILL }},
{ &hf_erspan_unknown3,
{ "Unknown3", "erspan.unknown3", FT_UINT16, BASE_DEC, NULL,
0x0800, NULL, HFILL }},
{ &hf_erspan_truncated,
{ "Truncated", "erspan.truncated", FT_UINT16, BASE_DEC, VALS(erspan_truncated_vals),
0x0400, "ERSPAN packet exceeded the MTU size", HFILL }},
{ &hf_erspan_spanid,
{ "SpanID", "erspan.spanid", FT_UINT16, BASE_DEC, NULL,
0x03ff, NULL, HFILL }},
{ &hf_erspan_timestamp,
{ "Timestamp", "erspan.timestamp", FT_UINT32, BASE_CUSTOM, erspan_fmt_timestamp,
0, NULL, HFILL }},
{ &hf_erspan_unknown4,
{ "Unknown4", "erspan.unknown4", FT_BYTES, BASE_NONE, NULL,
0, NULL, HFILL }},
{ &hf_erspan_direction2,
{ "Direction2", "erspan.direction2", FT_UINT16, BASE_DEC, VALS(erspan_direction_vals),
0x0008, NULL, HFILL }},
{ &hf_erspan_unknown5,
{ "Unknown5", "erspan.unknown5", FT_UINT16, BASE_HEX, NULL,
0xfff7, NULL, HFILL }},
{ &hf_erspan_unknown6,
{ "Unknown6", "erspan.unknown6", FT_BYTES, BASE_NONE, NULL,
0, NULL, HFILL }},
{ &hf_erspan_unknown7,
{ "Unknown7", "erspan.unknown7", FT_BYTES, BASE_NONE, NULL,
0, NULL, HFILL }},
};
static gint *ett[] = {
&ett_erspan,
};
static ei_register_info ei[] = {
{ &ei_erspan_version_unknown, { "erspan.version.unknown", PI_UNDECODED, PI_WARN, "Unknown version, please report or test to use fake ERSPAN preference", EXPFILL }},
};
proto_erspan = proto_register_protocol(PROTO_LONG_NAME, PROTO_SHORT_NAME, "erspan");
proto_register_field_array(proto_erspan, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_erspan = expert_register_protocol(proto_erspan);
expert_register_field_array(expert_erspan, ei, array_length(ei));
/* register dissection preferences */
erspan_module = prefs_register_protocol(proto_erspan, NULL);
prefs_register_bool_preference(erspan_module, "fake_erspan",
"FORCE to decode fake ERSPAN frame",
"When set, dissector will FORCE to decode directly Ethernet Frame"
"Some vendor use fake ERSPAN frame (with not ERSPAN Header)",
&pref_fake_erspan);
}
void
proto_reg_handoff_erspan(void)
{
dissector_handle_t erspan_handle;
ethnofcs_handle = find_dissector("eth_withoutfcs");
erspan_handle = create_dissector_handle(dissect_erspan, proto_erspan);
dissector_add_uint("gre.proto", GRE_ERSPAN_88BE, erspan_handle);
dissector_add_uint("gre.proto", GRE_ERSPAN_22EB, erspan_handle);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
|
