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
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
|
/* packet-cisco-mcp.c
* Routines for the disassembly of Cisco's MCP (MisCabling Protocol)
*
* Copyright 2019 Joerg Mayer (see AUTHORS file)
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
/*
TODO:
- Figure out the hash calculation
- Figure out strict mode tlv
Specs: No specs available
No header
Sequence of TLVs of format
Type (1 byte)
Length (1 byte)
Value (Length bytes of Data)
Patent:
http://www.freepatentsonline.com/20150124643.pdf
Documentation:
https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c11-737909.pdf
https://unofficialaciguide.com/2018/03/27/using-mcp-miscabling-protocol-for-aci/
knet_parser.py from Cisco
Strict mode:
https://www.cisco.com/c/en/us/td/docs/dcn/aci/apic/5x/aci-fundamentals/cisco-aci-fundamentals-52x/fundamentals-52x.html#Cisco_Concept.dita_637b67a2-6826-4cc4-8fbf-6998dc791d8b
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/expert.h>
#include <epan/to_str.h>
#include <epan/cisco_pid.h>
void proto_register_mcp(void);
void proto_reg_handoff_mcp(void);
static dissector_handle_t mcp_handle;
static int proto_mcp;
/* TLV header */
static int hf_mcp_tlv_type;
static int hf_mcp_strict_tlv_type;
static int hf_mcp_tlv_length;
/* Values */
static int hf_mcp_fabric_id;
static int hf_mcp_node_id;
static int hf_mcp_vpc_domain;
static int hf_mcp_vpc_id;
static int hf_mcp_vpc_vtep;
static int hf_mcp_port_id;
static int hf_mcp_send_time;
static int hf_mcp_strictmode;
static int hf_mcp_digest;
static int hf_mcp_unknown;
static expert_field ei_mcp_short_tlv;
static expert_field ei_mcp_trailing_bytes;
static expert_field ei_mcp_unexpected_tlv_length;
static int ett_mcp;
static int ett_mcp_tlv_header;
#define PROTO_SHORT_NAME "MCP"
#define PROTO_LONG_NAME "Miscabling Protocol"
// non-strict mode
typedef enum { // Total length of MCPDU = 62
MCP_TYPE_FABRIC_ID = 1, // Len=4,
MCP_TYPE_NODE_ID = 2, // Len=4,
MCP_TYPE_VPC_INFO = 3, // Len=12,
MCP_TYPE_PORT_ID = 4, // Len=4,
MCP_TYPE_SEND_TIME = 5, // Len=4,
MCP_TYPE_DIGEST = 6, // Len=20,
MCP_TYPE_END = 7 // Len=0
} mcp_type_t;
// strict mode - minimum ACI software: 5.2(4)
typedef enum { // Total length of MCPDU = 68
MCPS_TYPE_FABRIC_ID = 1, // Len=4,
MCPS_TYPE_NODE_ID = 2, // Len=4,
MCPS_TYPE_VPC_INFO = 3, // Len=12,
MCPS_TYPE_PORT_ID = 4, // Len=4,
MCPS_TYPE_SEND_TIME = 5, // Len=4,
MCPS_TYPE_STRICTMODE = 6, // Len=4
MCPS_TYPE_DIGEST = 7, // Len=20,
MCPS_TYPE_END = 8 // Len=0
} mcp_strict_type_t;
static const value_string mcp_type_vals[] = {
{ MCP_TYPE_FABRIC_ID, "Fabric ID"},
{ MCP_TYPE_NODE_ID, "Node ID"},
{ MCP_TYPE_VPC_INFO, "VPC Info"},
{ MCP_TYPE_PORT_ID, "Port ID"},
{ MCP_TYPE_SEND_TIME, "Send Time"},
{ MCP_TYPE_DIGEST, "Digest"},
{ MCP_TYPE_END, "End"},
{ 0, NULL }
};
static const value_string mcp_strict_type_vals[] = {
{ MCPS_TYPE_FABRIC_ID, "Fabric ID"},
{ MCPS_TYPE_NODE_ID, "Node ID"},
{ MCPS_TYPE_VPC_INFO, "VPC Info"},
{ MCPS_TYPE_PORT_ID, "Port ID"},
{ MCPS_TYPE_SEND_TIME, "Send Time"},
{ MCPS_TYPE_STRICTMODE, "Strictmode?"},
{ MCPS_TYPE_DIGEST, "Digest"},
{ MCPS_TYPE_END, "End"},
{ 0, NULL }
};
static int
dissect_mcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_item *ti, *pi;
proto_tree *mcp_tree;
proto_tree *tlv_tree;
uint32_t offset = 0;
bool last = false;
bool strict_mode = true;
uint8_t tlv_type, use_tlv;
uint16_t tlv_length;
uint16_t data_length = tvb_reported_length_remaining(tvb, offset);
uint32_t fabricid, nodeid, vpcdomain, vpcid, portid, sendtime, strictmode;
char *sendtime_str, *vpcvtep_str;
col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_SHORT_NAME);
col_clear(pinfo->cinfo, COL_INFO);
ti = proto_tree_add_item(tree, proto_mcp, tvb, offset, -1,
ENC_NA);
mcp_tree = proto_item_add_subtree(ti, ett_mcp);
/* No header whatsoever, just a plain sequence of TLVs */
while (offset < data_length && !last) {
if (data_length - offset < 2) {
proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_short_tlv, tvb,
offset, data_length, "Too few bytes left for TLV (%u < 2)", data_length - offset);
break;
}
tlv_type = tvb_get_uint8(tvb, offset);
// HACK: Interestring version handling
use_tlv = tlv_type;
if (data_length == 62) {
strict_mode = false;
if (tlv_type >= MCPS_TYPE_STRICTMODE) {
use_tlv = tlv_type + 1;
}
}
tlv_length = tvb_get_uint8(tvb, offset + 1);
if (strict_mode) {
tlv_tree = proto_tree_add_subtree_format(mcp_tree, tvb, offset, tlv_length + 2,
ett_mcp_tlv_header, NULL, "%s", val_to_str(tlv_type, mcp_strict_type_vals, "Unknown (0x%02x)"));
proto_tree_add_uint(tlv_tree, hf_mcp_strict_tlv_type, tvb, offset, 1, tlv_type);
} else {
tlv_tree = proto_tree_add_subtree_format(mcp_tree, tvb, offset, tlv_length + 2,
ett_mcp_tlv_header, NULL, "%s", val_to_str(tlv_type, mcp_type_vals, "Unknown (0x%02x)"));
proto_tree_add_uint(tlv_tree, hf_mcp_tlv_type, tvb, offset, 1, tlv_type);
}
offset += 1;
proto_tree_add_uint(tlv_tree, hf_mcp_tlv_length, tvb, offset, 1, tlv_length);
if (tlv_length > (data_length - (offset + 1))) {
proto_tree_add_expert_format(tlv_tree, pinfo, &ei_mcp_short_tlv, tvb,
offset, 1, "TLV length (%u) passes end of packet", tlv_length);
break;
}
offset += 1;
switch (use_tlv) {
case MCPS_TYPE_FABRIC_ID:
if (tlv_length == 4) {
proto_tree_add_item_ret_uint(tlv_tree, hf_mcp_fabric_id, tvb, offset, tlv_length, ENC_BIG_ENDIAN, &fabricid);
proto_item_append_text(tlv_tree, ": %u", fabricid);
col_append_fstr(pinfo->cinfo, COL_INFO, "FabricID/%u ", fabricid);
} else {
proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
4, tlv_length);
}
break;
case MCPS_TYPE_NODE_ID:
if (tlv_length == 4) {
proto_tree_add_item_ret_uint(tlv_tree, hf_mcp_node_id, tvb, offset, tlv_length, ENC_BIG_ENDIAN, &nodeid);
proto_item_append_text(tlv_tree, ": %u", nodeid);
col_append_fstr(pinfo->cinfo, COL_INFO, "NodeID/%u ", nodeid);
} else {
proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
4, tlv_length);
}
break;
case MCPS_TYPE_VPC_INFO:
proto_tree_add_item_ret_uint(tlv_tree, hf_mcp_vpc_domain, tvb, offset, 4, ENC_NA, &vpcdomain);
proto_tree_add_item_ret_uint(tlv_tree, hf_mcp_vpc_id, tvb, offset + 4, 4, ENC_NA, &vpcid);
pi = proto_tree_add_item(tlv_tree, hf_mcp_vpc_vtep, tvb, offset + 8, 4, ENC_NA);
vpcvtep_str = proto_item_get_display_repr(pinfo->pool, pi);
proto_item_append_text(tlv_tree, ": %u/%u/%s", vpcdomain, vpcid, vpcvtep_str);
// FIXME: Why is vpcvtep_str displayed as "(null)" in COL_INFO but not above??? scope???
if (vpcvtep_str)
col_append_fstr(pinfo->cinfo, COL_INFO, "VpcInfo/%u,%u,%s ", vpcdomain, vpcid, vpcvtep_str);
break;
case MCPS_TYPE_PORT_ID:
if (tlv_length == 4) {
proto_tree_add_item_ret_uint(tlv_tree, hf_mcp_port_id, tvb, offset, tlv_length, ENC_BIG_ENDIAN, &portid);
proto_item_append_text(tlv_tree, ": 0x%08x", portid);
col_append_fstr(pinfo->cinfo, COL_INFO, "PortID/0x%08x ", portid);
} else {
proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
4, tlv_length);
}
break;
case MCPS_TYPE_SEND_TIME:
if (tlv_length == 4) {
proto_tree_add_item(tlv_tree, hf_mcp_send_time, tvb, offset, tlv_length, ENC_TIME_SECS|ENC_BIG_ENDIAN);
sendtime = tvb_get_ntohl(tvb, offset);
sendtime_str = abs_time_secs_to_str(pinfo->pool, sendtime, ABSOLUTE_TIME_LOCAL, true);
proto_item_append_text(tlv_tree, ": %s", sendtime_str);
col_append_fstr(pinfo->cinfo, COL_INFO, "SendTime/%s ", sendtime_str);
} else {
proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
4, tlv_length);
}
break;
case MCPS_TYPE_STRICTMODE:
if (tlv_length == 4) {
proto_tree_add_item_ret_uint(tlv_tree, hf_mcp_strictmode, tvb, offset, tlv_length, ENC_BIG_ENDIAN, &strictmode);
proto_item_append_text(tlv_tree, ": %d", strictmode);
col_append_fstr(pinfo->cinfo, COL_INFO, "Unk1/%d ", strictmode);
} else {
proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
4, tlv_length);
}
break;
case MCPS_TYPE_DIGEST:
if (tlv_length == 20) {
proto_tree_add_item(tlv_tree, hf_mcp_digest, tvb, offset, tlv_length, ENC_NA);
} else {
proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
20, tlv_length);
}
break;
case MCPS_TYPE_END:
last = true;
if (tlv_length != 0) {
proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
0, tlv_length);
}
break;
default:
proto_tree_add_item(tlv_tree, hf_mcp_unknown, tvb, offset, tlv_length, ENC_NA);
break;
}
offset += tlv_length;
}
if (offset < data_length) {
proto_tree_add_expert(mcp_tree, pinfo, &ei_mcp_trailing_bytes, tvb, offset,
data_length - offset);
}
return tvb_captured_length(tvb);
}
void
proto_register_mcp(void)
{
static hf_register_info hf[] = {
/* TLV header (aka TL) */
{ &hf_mcp_tlv_type,
{ "TLV type", "mcp.tlv.type", FT_UINT8, BASE_DEC, VALS(mcp_type_vals),
0x0, NULL, HFILL }},
{ &hf_mcp_strict_tlv_type,
{ "TLV type", "mcp.tlv.type", FT_UINT8, BASE_DEC, VALS(mcp_strict_type_vals),
0x0, NULL, HFILL }},
{ &hf_mcp_tlv_length,
{ "TLV length", "mcp.tlv.length", FT_UINT16, BASE_DEC, NULL,
0x0, NULL, HFILL }},
/* TLV data (aka V) */
{ &hf_mcp_fabric_id,
{ "Fabric ID", "mcp.fabric_id", FT_UINT32, BASE_DEC, NULL,
0x0, NULL, HFILL }},
{ &hf_mcp_node_id,
{ "Node ID", "mcp.node_id", FT_UINT32, BASE_DEC, NULL,
0x0, "Originating Switch", HFILL }},
{ &hf_mcp_vpc_domain,
{ "VPC Domain", "mcp.vpc.domain", FT_UINT32, BASE_DEC, NULL,
0x0, NULL, HFILL }},
{ &hf_mcp_vpc_id,
{ "VPC ID", "mcp.vpc.id", FT_UINT32, BASE_DEC, NULL,
0x0, NULL, HFILL }},
{ &hf_mcp_vpc_vtep,
{ "VPC VTEP", "mcp.vpc.vtep", FT_IPv4, BASE_NONE, NULL,
0x0, NULL, HFILL }},
{ &hf_mcp_port_id,
{ "Port ID", "mcp.port_id", FT_UINT32, BASE_HEX, NULL,
0x0, NULL, HFILL }},
{ &hf_mcp_send_time,
{ "Send Time", "mcp.send_time", FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL,
0x0, NULL, HFILL }},
{ &hf_mcp_strictmode,
{ "Strict Mode?", "mcp.strictmode", FT_UINT32, BASE_DEC, NULL,
0x0, NULL, HFILL }},
{ &hf_mcp_digest,
{ "Digest", "mcp.digest", FT_BYTES, BASE_NONE, NULL,
0x0, NULL, HFILL }},
{ &hf_mcp_unknown,
{ "Unknown", "mcp.unknown", FT_BYTES, BASE_NONE, NULL,
0x0, NULL, HFILL }},
};
static int *ett[] = {
&ett_mcp,
&ett_mcp_tlv_header,
};
static ei_register_info ei[] = {
{ &ei_mcp_short_tlv,
{ "mcp.short_tlv", PI_MALFORMED, PI_ERROR,
"TLV is too short", EXPFILL }},
{ &ei_mcp_trailing_bytes,
{ "mcp.trailing_bytes", PI_PROTOCOL, PI_WARN,
"Trailing bytes after last TLV", EXPFILL }},
{ &ei_mcp_unexpected_tlv_length,
{ "mcp.unexpected_tlv_length", PI_PROTOCOL, PI_WARN,
"Expected Value length differs from seen length", EXPFILL }},
};
expert_module_t* expert_mcp;
proto_mcp = proto_register_protocol(PROTO_LONG_NAME, PROTO_SHORT_NAME, "mcp");
proto_register_field_array(proto_mcp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_mcp = expert_register_protocol(proto_mcp);
expert_register_field_array(expert_mcp, ei, array_length(ei));
mcp_handle = register_dissector("mcp", dissect_mcp, proto_mcp);
}
void
proto_reg_handoff_mcp(void)
{
dissector_add_uint("llc.cisco_pid", CISCO_PID_MCP, mcp_handle);
}
/*
* Editor modelines - https://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:
*/
|
