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
390
391
|
/*
* packet-rtcdc.c
* Routines for the RTCWeb Data Channel Protocol dissection
* as specified in
* https://tools.ietf.org/html/draft-jesup-rtcweb-data-protocol-03
* and specified in
* https://tools.ietf.org/html/draft-ietf-rtcweb-data-protocol-08
* We might want to remove the support of
* https://tools.ietf.org/html/draft-jesup-rtcweb-data-protocol-03
* in the future, but I'll leave it in for now.
* Copyright 2012 - 2013, Michael Tuexen <tuexen@wireshark.org>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/expert.h>
#include <epan/prefs.h>
#include <epan/sctpppids.h>
void proto_register_rtcdc(void);
void proto_reg_handoff_rtcdc(void);
static dissector_handle_t rtcdc_handle;
/* Initialize the protocol and registered fields */
static int proto_rtcdc = -1;
static int hf_message_type = -1;
static int hf_channel_type = -1;
static int hf_flags = -1;
static int hf_flags_reserved = -1;
static int hf_unordered_allowed = -1;
static int hf_reliability = -1;
static int hf_priority = -1;
static int hf_label = -1;
static int hf_error = -1;
static int hf_sid = -1;
static int hf_new_channel_type = -1;
static int hf_new_reliability = -1;
static int hf_new_priority = -1;
static int hf_new_label_length = -1;
static int hf_new_protocol_length = -1;
static int hf_new_label = -1;
static int hf_new_protocol = -1;
/* Initialize the subtree pointers */
static gint ett_rtcdc = -1;
static gint ett_flags = -1;
static expert_field ei_rtcdc_new_reliability_non_zero = EI_INIT;
static expert_field ei_rtcdc_message_type_unknown = EI_INIT;
static expert_field ei_rtcdc_inconsistent_label_and_parameter_length = EI_INIT;
static expert_field ei_rtcdc_message_too_long = EI_INIT;
static expert_field ei_rtcdc_new_channel_type = EI_INIT;
#define DATA_CHANNEL_OPEN_REQUEST 0x00
#define DATA_CHANNEL_OPEN_RESPONSE 0x01
#define DATA_CHANNEL_ACK 0x02
#define DATA_CHANNEL_NEW_OPEN_REQUEST 0x03
static const value_string message_type_values[] = {
{ DATA_CHANNEL_OPEN_REQUEST, "DATA_CHANNEL_OPEN_REQUEST" },
{ DATA_CHANNEL_OPEN_RESPONSE, "DATA_CHANNEL_OPEN_RESPONSE" },
{ DATA_CHANNEL_ACK, "DATA_CHANNEL_ACK" },
{ DATA_CHANNEL_NEW_OPEN_REQUEST, "DATA_CHANNEL_OPEN_REQUEST" },
{ 0, NULL }
};
#define DATA_CHANNEL_RELIABLE 0x00
#define DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT 0x01
#define DATA_CHANNEL_PARTIAL_RELIABLE_TIMED 0x02
static const value_string channel_type_values[] = {
{ DATA_CHANNEL_RELIABLE, "DATA_CHANNEL_RELIABLE" },
{ DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT, "DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT" },
{ DATA_CHANNEL_PARTIAL_RELIABLE_TIMED, "DATA_CHANNEL_PARTIAL_RELIABLE_TIMED" },
{ 0, NULL }
};
#define MESSAGE_TYPE_LENGTH 1
#define CHANNEL_TYPE_LENGTH 1
#define FLAGS_LENGTH 2
#define RELIABILITY_LENGTH 2
#define PRIORITY_LENGTH 2
#define MESSAGE_TYPE_OFFSET 0
#define CHANNEL_TYPE_OFFSET (MESSAGE_TYPE_OFFSET + MESSAGE_TYPE_LENGTH)
#define FLAGS_OFFSET (CHANNEL_TYPE_OFFSET + CHANNEL_TYPE_LENGTH)
#define RELIABILITY_OFFSET (FLAGS_OFFSET + FLAGS_LENGTH)
#define PRIORITY_OFFSET (RELIABILITY_OFFSET + RELIABILITY_LENGTH)
#define LABEL_OFFSET (PRIORITY_OFFSET + PRIORITY_LENGTH)
#define DATA_CHANNEL_FLAG_OUT_OF_ORDER_ALLOWED_MASK 0x0001
#define DATA_CHANNEL_FLAG_RESERVED_MASK 0xFFFE
static void
dissect_open_request_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *rtcdc_tree, proto_item *rtcdc_item _U_)
{
if (rtcdc_tree) {
proto_tree *flags_tree;
proto_item *flags_item;
proto_tree_add_item(rtcdc_tree, hf_channel_type, tvb, CHANNEL_TYPE_OFFSET, CHANNEL_TYPE_LENGTH, ENC_BIG_ENDIAN);
flags_item = proto_tree_add_item(rtcdc_tree, hf_flags, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN);
flags_tree = proto_item_add_subtree(flags_item, ett_flags);
proto_tree_add_item(flags_tree, hf_flags_reserved, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(flags_tree, hf_unordered_allowed, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_reliability, tvb, RELIABILITY_OFFSET, RELIABILITY_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_priority, tvb, PRIORITY_OFFSET, PRIORITY_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_label, tvb, LABEL_OFFSET, -1, ENC_ASCII);
}
return;
}
#define ERROR_LENGTH 1
#define SID_LENGTH 2
#define DATA_CHANNEL_RESPONSE_LENGTH (MESSAGE_TYPE_LENGTH + ERROR_LENGTH + FLAGS_LENGTH + SID_LENGTH)
#define ERROR_OFFSET (MESSAGE_TYPE_OFFSET + MESSAGE_TYPE_LENGTH)
#define SID_OFFSET (FLAGS_OFFSET + FLAGS_LENGTH)
static void
dissect_open_response_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *rtcdc_tree, proto_item *rtcdc_item)
{
if (tvb_reported_length(tvb) > DATA_CHANNEL_RESPONSE_LENGTH) {
expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_message_too_long);
}
if (rtcdc_tree) {
proto_tree_add_item(rtcdc_tree, hf_error, tvb, ERROR_OFFSET, ERROR_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_flags, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_sid, tvb, SID_OFFSET, SID_LENGTH, ENC_BIG_ENDIAN);
}
return;
}
#define DATA_CHANNEL_ACK_LENGTH MESSAGE_TYPE_LENGTH
static void
dissect_open_ack_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *rtcdc_tree _U_, proto_item *rtcdc_item)
{
if (tvb_reported_length(tvb) > DATA_CHANNEL_ACK_LENGTH) {
expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_message_too_long);
}
return;
}
#define NEW_DATA_CHANNEL_RELIABLE 0x00
#define NEW_DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT 0x01
#define NEW_DATA_CHANNEL_PARTIAL_RELIABLE_TIMED 0x02
#define NEW_DATA_CHANNEL_RELIABLE_UNORDERED 0x80
#define NEW_DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED 0x81
#define NEW_DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED 0x82
static const value_string new_channel_type_values[] = {
{ NEW_DATA_CHANNEL_RELIABLE, "DATA_CHANNEL_RELIABLE" },
{ NEW_DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT, "DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT" },
{ NEW_DATA_CHANNEL_PARTIAL_RELIABLE_TIMED, "DATA_CHANNEL_PARTIAL_RELIABLE_TIMED" },
{ NEW_DATA_CHANNEL_RELIABLE_UNORDERED, "DATA_CHANNEL_RELIABLE_UNORDERED" },
{ NEW_DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED, "DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED" },
{ NEW_DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED, "DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED" },
{ 0, NULL }
};
#define NEW_MESSAGE_TYPE_LENGTH 1
#define NEW_CHANNEL_TYPE_LENGTH 1
#define NEW_PRIORITY_LENGTH 2
#define NEW_RELIABILITY_LENGTH 4
#define NEW_LABEL_LENGTH_LENGTH 2
#define NEW_PROTOCOL_LENGTH_LENGTH 2
#define NEW_OPEN_REQUEST_HEADER_LENGTH (guint)(NEW_MESSAGE_TYPE_LENGTH + \
NEW_CHANNEL_TYPE_LENGTH + \
NEW_PRIORITY_LENGTH + \
NEW_RELIABILITY_LENGTH + \
NEW_LABEL_LENGTH_LENGTH + \
NEW_PROTOCOL_LENGTH_LENGTH)
#define NEW_MESSAGE_TYPE_OFFSET 0
#define NEW_CHANNEL_TYPE_OFFSET (NEW_MESSAGE_TYPE_OFFSET + NEW_MESSAGE_TYPE_LENGTH)
#define NEW_PRIORITY_OFFSET (NEW_CHANNEL_TYPE_OFFSET + NEW_CHANNEL_TYPE_LENGTH)
#define NEW_RELIABILITY_OFFSET (NEW_PRIORITY_OFFSET + NEW_PRIORITY_LENGTH)
#define NEW_LABEL_LENGTH_OFFSET (NEW_RELIABILITY_OFFSET + NEW_RELIABILITY_LENGTH)
#define NEW_PROTOCOL_LENGTH_OFFSET (NEW_LABEL_LENGTH_OFFSET + NEW_LABEL_LENGTH_LENGTH)
#define NEW_LABEL_OFFSET (NEW_PROTOCOL_LENGTH_OFFSET + NEW_PROTOCOL_LENGTH_LENGTH)
static void
dissect_new_open_request_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *rtcdc_tree, proto_item *rtcdc_item)
{
guint8 channel_type;
guint32 reliability;
guint16 label_length;
guint16 protocol_length;
channel_type = tvb_get_guint8(tvb, NEW_CHANNEL_TYPE_OFFSET);
if ((channel_type & 0x7f) > 0x02) {
expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_new_channel_type);
}
reliability = tvb_get_ntohl(tvb, NEW_RELIABILITY_OFFSET);
if ((reliability > 0) && ((channel_type & 0x7f) == 0x00)) {
expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_new_reliability_non_zero);
}
label_length = tvb_get_ntohs(tvb, NEW_LABEL_LENGTH_OFFSET);
protocol_length = tvb_get_ntohs(tvb, NEW_PROTOCOL_LENGTH_OFFSET);
if (NEW_OPEN_REQUEST_HEADER_LENGTH + (guint)label_length + (guint)protocol_length != tvb_reported_length(tvb)) {
expert_add_info(pinfo, rtcdc_item, &ei_rtcdc_inconsistent_label_and_parameter_length);
}
if (rtcdc_tree) {
proto_tree_add_item(rtcdc_tree, hf_new_channel_type, tvb, NEW_CHANNEL_TYPE_OFFSET, NEW_CHANNEL_TYPE_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_new_priority, tvb, NEW_PRIORITY_OFFSET, NEW_PRIORITY_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_new_reliability, tvb, NEW_RELIABILITY_OFFSET, NEW_RELIABILITY_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_new_label_length, tvb, NEW_LABEL_LENGTH_OFFSET, NEW_LABEL_LENGTH_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_new_protocol_length, tvb, NEW_PROTOCOL_LENGTH_OFFSET, NEW_PROTOCOL_LENGTH_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_new_label, tvb, NEW_LABEL_OFFSET, label_length, ENC_ASCII);
proto_tree_add_item(rtcdc_tree, hf_new_protocol, tvb, NEW_LABEL_OFFSET + label_length, protocol_length, ENC_ASCII);
}
return;
}
static int
dissect_rtcdc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
proto_item *rtcdc_item, *msg_item;
proto_tree *rtcdc_tree;
guint8 message_type;
message_type = tvb_get_guint8(tvb, MESSAGE_TYPE_OFFSET);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "RTCDC");
col_add_fstr(pinfo->cinfo, COL_INFO, "%s ", val_to_str_const(message_type, message_type_values, "reserved"));
rtcdc_item = proto_tree_add_item(tree, proto_rtcdc, tvb, 0, -1, ENC_NA);
rtcdc_tree = proto_item_add_subtree(rtcdc_item, ett_rtcdc);
msg_item = proto_tree_add_item(rtcdc_tree, hf_message_type, tvb, MESSAGE_TYPE_OFFSET, MESSAGE_TYPE_LENGTH, ENC_BIG_ENDIAN);
switch (message_type) {
case DATA_CHANNEL_OPEN_REQUEST:
dissect_open_request_message(tvb, pinfo, rtcdc_tree, rtcdc_item);
break;
case DATA_CHANNEL_OPEN_RESPONSE:
dissect_open_response_message(tvb, pinfo, rtcdc_tree, rtcdc_item);
break;
case DATA_CHANNEL_ACK:
dissect_open_ack_message(tvb, pinfo, rtcdc_tree, rtcdc_item);
break;
case DATA_CHANNEL_NEW_OPEN_REQUEST:
dissect_new_open_request_message(tvb, pinfo, rtcdc_tree, rtcdc_item);
break;
default:
expert_add_info(pinfo, msg_item, &ei_rtcdc_message_type_unknown);
break;
}
return tvb_captured_length(tvb);
}
void
proto_register_rtcdc(void)
{
expert_module_t *expert_rtcdc;
static hf_register_info hf[] = {
{ &hf_message_type,
{ "Message type", "rtcdc.message_type",
FT_UINT8, BASE_DEC, VALS(message_type_values), 0x0,
NULL, HFILL }
},
{ &hf_channel_type,
{ "Channel type", "rtcdc.channel_type",
FT_UINT8, BASE_DEC, VALS(channel_type_values), 0x0,
NULL, HFILL }
},
{ &hf_flags,
{ "Flags", "rtcdc.flags",
FT_UINT16, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_flags_reserved,
{ "Reserved", "rtcdc.flags_reserved",
FT_UINT16, BASE_HEX, NULL, DATA_CHANNEL_FLAG_RESERVED_MASK,
NULL, HFILL }
},
{ &hf_unordered_allowed,
{ "Unordered allowed", "rtcdc.flags_unordered_allowed",
FT_BOOLEAN, 16, NULL, DATA_CHANNEL_FLAG_OUT_OF_ORDER_ALLOWED_MASK,
NULL, HFILL }
},
{ &hf_reliability,
{ "Reliability parameter", "rtcdc.reliability_parameter",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_priority,
{ "Priority", "rtcdc.priority",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_label,
{ "Label", "rtcdc.label",
FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_error,
{ "Error", "rtcdc.error",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_sid,
{ "Reverse stream identifier", "rtcdc.reverse_stream_id",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_new_channel_type,
{ "Channel type", "rtcdc.channel_type",
FT_UINT8, BASE_DEC, VALS(new_channel_type_values), 0x0,
NULL, HFILL }
},
{ &hf_new_reliability,
{ "Reliability parameter", "rtcdc.reliability_parameter",
FT_UINT32, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_new_priority,
{ "Priority", "rtcdc.priority",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_new_label_length,
{ "Label length", "rtcdc.label_length",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_new_protocol_length,
{ "Protocol length", "rtcdc.protocol_length",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_new_label,
{ "Label", "rtcdc.label",
FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_new_protocol,
{ "Protocol", "rtcdc.protocol",
FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL }
}
};
static gint *ett[] = {
&ett_rtcdc,
&ett_flags
};
static ei_register_info ei[] = {
{ &ei_rtcdc_message_too_long, { "rtcdc.message_too_long", PI_MALFORMED, PI_ERROR, "Message too long", EXPFILL }},
{ &ei_rtcdc_new_channel_type, { "rtcdc.channel_type.unknown", PI_PROTOCOL, PI_WARN, "Unknown channel type", EXPFILL }},
{ &ei_rtcdc_new_reliability_non_zero, { "rtcdc.reliability_parameter.non_zero", PI_PROTOCOL, PI_WARN, "Reliability parameter non zero for reliable channel", EXPFILL }},
{ &ei_rtcdc_inconsistent_label_and_parameter_length, { "rtcdc.inconsistent_label_and_parameter_length", PI_MALFORMED, PI_ERROR, "Inconsistent label and parameter length", EXPFILL }},
{ &ei_rtcdc_message_type_unknown, { "rtcdc.message_type.unknown", PI_PROTOCOL, PI_WARN, "Unknown message type", EXPFILL }},
};
proto_rtcdc = proto_register_protocol("WebRTC Datachannel Protocol", "RTCDC", "rtcdc");
proto_register_field_array(proto_rtcdc, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_rtcdc = expert_register_protocol(proto_rtcdc);
expert_register_field_array(expert_rtcdc, ei, array_length(ei));
/* rtcdc_module = prefs_register_protocol(proto_rtcdc, NULL); */
rtcdc_handle = register_dissector("rtcdc", dissect_rtcdc, proto_rtcdc);
}
void
proto_reg_handoff_rtcdc(void)
{
dissector_add_uint_with_preference("sctp.ppi", WEBRTC_DCEP_PROTOCOL_ID, rtcdc_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
|
