aboutsummaryrefslogtreecommitdiffstats
path: root/epan/dissectors/packet-gsm_ipa.c
blob: a8abece057af7dbe19eec816403412837ffcdfe4 (plain)
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
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
/* packet-gsm_ipa.c
 * Routines for packet dissection of ip.access GSM A-bis over IP
 * Copyright 2009 by Harald Welte <laforge@gnumonks.org>
 * Copyright 2009, 2010 by Holger Hans Peter Freyther <zecke@selfish.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/prefs.h>

void proto_register_ipa(void);
void proto_reg_handoff_gsm_ipa(void);

/*
 * Protocol used by ip.access's nanoBTS/nanoGSM GSM picocells:
 *
 *	http://www.ipaccess.com/en/nanoGSM-picocell
 *
 * to transport the GSM A-bis interface over TCP and UDP.
 *
 * See
 *
 *	http://openbsc.osmocom.org/trac/wiki/nanoBTS
 *
 * for some information about this protocol determined by reverse-
 * engineering.
 */

/*
 * These ports are also registered for other protocols, as per
 *
 * http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml
 *
 * exlm-agent     3002
 * cgms           3003
 * ii-admin       3006
 * vrml-multi-use 4200-4299
 * commplex-main  5000
 *
 * But, as that document says:
 *
 ************************************************************************
 * PLEASE NOTE THE FOLLOWING:                                           *
 *                                                                      *
 * ASSIGNMENT OF A PORT NUMBER DOES NOT IN ANY WAY IMPLY AN             *
 * ENDORSEMENT OF AN APPLICATION OR PRODUCT, AND THE FACT THAT NETWORK  *
 * TRAFFIC IS FLOWING TO OR FROM A REGISTERED PORT DOES NOT MEAN THAT   *
 * IT IS "GOOD" TRAFFIC, NOR THAT IT NECESSARILY CORRESPONDS TO THE     *
 * ASSIGNED SERVICE. FIREWALL AND SYSTEM ADMINISTRATORS SHOULD          *
 * CHOOSE HOW TO CONFIGURE THEIR SYSTEMS BASED ON THEIR KNOWLEDGE OF    *
 * THE TRAFFIC IN QUESTION, NOT WHETHER THERE IS A PORT NUMBER          *
 * REGISTERED OR NOT.                                                   *
 ************************************************************************
 */
#define IPA_TCP_PORTS "3002,3003,3006,4249,4250,5000"

static dissector_handle_t ipa_tcp_handle;
static dissector_handle_t ipa_udp_handle;
static gboolean global_ipa_in_root = FALSE;
static gboolean global_ipa_in_info = FALSE;

/* Initialize the protocol and registered fields */
static int proto_ipa = -1;
static int proto_ipaccess = -1;

static int hf_ipa_data_len = -1;
static int hf_ipa_protocol = -1;
static int hf_ipa_hsl_debug = -1;
static int hf_ipa_osmo_proto = -1;
static int hf_ipa_osmo_ctrl_data = -1;

static int hf_ipaccess_msgtype = -1;
static int hf_ipaccess_attr_tag = -1;
static int hf_ipaccess_attr_string = -1;
static int hf_ipaccess_attribute_unk = -1;

/* Initialize the subtree pointers */
static gint ett_ipa = -1;
static gint ett_ipaccess = -1;

enum {
	SUB_OML,
	SUB_RSL,
	SUB_SCCP,
	SUB_MGCP,
/*	SUB_IPACCESS, */
	SUB_DATA,

	SUB_MAX
};

static dissector_handle_t sub_handles[SUB_MAX];
static dissector_table_t osmo_dissector_table;


#define ABISIP_RSL_MAX	0x20
#define HSL_DEBUG	0xdd
#define OSMO_EXT	0xee
#define IPA_MGCP	0xfc
#define AIP_SCCP	0xfd
#define ABISIP_IPACCESS	0xfe
#define ABISIP_OML	0xff
#define IPAC_PROTO_EXT_CTRL	0x00
#define IPAC_PROTO_EXT_MGCP	0x01

static const value_string ipa_protocol_vals[] = {
	{ 0x00,		"RSL" },
	{ 0xdd,		"HSL Debug" },
	{ 0xee,		"OSMO EXT" },
	{ 0xfc,		"MGCP (old)" },
	{ 0xfd,		"SCCP" },
	{ 0xfe,		"IPA" },
	{ 0xff,		"OML" },
	{ 0,		NULL }
};

static const value_string ipaccess_msgtype_vals[] = {
	{ 0x00,		"PING?" },
	{ 0x01, 	"PONG!" },
	{ 0x04, 	"IDENTITY REQUEST" },
	{ 0x05, 	"IDENTITY RESPONSE" },
	{ 0x06, 	"IDENTITY ACK" },
	{ 0x07, 	"IDENTITY NACK" },
	{ 0x08,		"PROXY REQUEST" },
	{ 0x09,		"PROXY ACK" },
	{ 0x0a,		"PROXY NACK" },
	{ 0,		NULL }
};

static const value_string ipaccess_idtag_vals[] = {
	{ 0x00,		"Serial Number" },
	{ 0x01,		"Unit Name" },
	{ 0x02,		"Location" },
	{ 0x03,		"Unit Type" },
	{ 0x04,		"Equipment Version" },
	{ 0x05,		"Software Version" },
	{ 0x06,		"IP Address" },
	{ 0x07,		"MAC Address" },
	{ 0x08,		"Unit ID" },
	{ 0,		NULL }
};

static const value_string ipa_osmo_proto_vals[] = {
	{ 0x00,		"CTRL" },
	{ 0x01,		"MGCP" },
	{ 0x02,		"LAC" },
	{ 0x03,		"SMSC" },
	{ 0,		NULL }
};


static gint
dissect_ipa_attr(tvbuff_t *tvb, int base_offs, proto_tree *tree)
{
	guint8 len, attr_type;

	int offset = base_offs;

	while (tvb_reported_length_remaining(tvb, offset) > 0) {
		attr_type = tvb_get_guint8(tvb, offset);

		switch (attr_type) {
		case 0x00:	/* a string prefixed by its length */
			len = tvb_get_guint8(tvb, offset+1);
			proto_tree_add_item(tree, hf_ipaccess_attr_tag,
					    tvb, offset+2, 1, ENC_BIG_ENDIAN);
			proto_tree_add_item(tree, hf_ipaccess_attr_string,
					    tvb, offset+3, len-1, ENC_ASCII|ENC_NA);
			break;
		case 0x01:	/* a single-byte request for a certain attr */
			len = 0;
			proto_tree_add_item(tree, hf_ipaccess_attr_tag,
					    tvb, offset+1, 1, ENC_BIG_ENDIAN);
			break;
		default:
			len = 0;
			proto_tree_add_uint(tree, hf_ipaccess_attribute_unk, tvb, offset+1, 1,
					    attr_type);
			break;
		};
		offset += len + 2;
	};
	return offset;
}

/* Dissect an ip.access specific message */
static gint
dissect_ipaccess(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
	proto_item *ti;
	proto_tree *ipaccess_tree;
	guint8 msg_type;

	msg_type = tvb_get_guint8(tvb, 0);

	col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
	                val_to_str(msg_type, ipaccess_msgtype_vals,
	                           "unknown 0x%02x"));
	ti = proto_tree_add_item(tree, proto_ipaccess, tvb, 0, -1, ENC_NA);
	ipaccess_tree = proto_item_add_subtree(ti, ett_ipaccess);
	proto_tree_add_item(ipaccess_tree, hf_ipaccess_msgtype,
			tvb, 0, 1, ENC_BIG_ENDIAN);
	switch (msg_type) {
		case 4:
		case 5:
			dissect_ipa_attr(tvb, 1, ipaccess_tree);
			break;
	}

	return 1;
}

/* Dissect the osmocom extension header */
static gint
dissect_osmo(tvbuff_t *tvb, packet_info *pinfo, proto_tree *ipatree, proto_tree *tree, proto_item *ipa_ti)
{
	tvbuff_t *next_tvb;
	guint8 osmo_proto;
	const gchar *name;

	osmo_proto = tvb_get_guint8(tvb, 0);
	name = val_to_str(osmo_proto, ipa_osmo_proto_vals, "unknown 0x%02x");
	col_append_fstr(pinfo->cinfo, COL_INFO, "%s ", name);
	if (ipatree) {
		proto_item_append_text(ipa_ti, " %s", name);
		proto_tree_add_item(ipatree, hf_ipa_osmo_proto,
				    tvb, 0, 1, ENC_BIG_ENDIAN);
	}

	next_tvb = tvb_new_subset_remaining(tvb, 1);

	/* Call any subdissectors that registered for this protocol */
	if (dissector_try_uint(osmo_dissector_table, osmo_proto, next_tvb, pinfo, tree))
		return 1;

	/* Fallback to the standard MGCP dissector */
	if (osmo_proto == IPAC_PROTO_EXT_MGCP) {
		call_dissector(sub_handles[SUB_MGCP], next_tvb, pinfo, tree);
		return 1;
	/* Simply display the CTRL data as text */
	} else if (osmo_proto == IPAC_PROTO_EXT_CTRL) {
		proto_tree_add_item(tree, hf_ipa_osmo_ctrl_data, next_tvb, 0, -1, ENC_ASCII|ENC_NA);
		return 1;
	}

	call_dissector(sub_handles[SUB_DATA], next_tvb, pinfo, tree);

	return 1;
}



/* Code to actually dissect the packets */
static void
dissect_ipa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean is_udp)
{
	gint remaining;
	gint header_length = 3;
	int offset = 0;

	col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPA");
	col_clear(pinfo->cinfo, COL_INFO);

	while ((remaining = tvb_reported_length_remaining(tvb, offset)) > 0) {
		proto_item *ti;
		proto_tree *ipa_tree = NULL;
		guint16 len, msg_type;
		tvbuff_t *next_tvb;

		len = tvb_get_ntohs(tvb, offset);
		msg_type = tvb_get_guint8(tvb, offset+2);

		col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
		                val_to_str(msg_type, ipa_protocol_vals,
		                           "unknown 0x%02x"));

		/*
		 * The IPA header is different depending on the transport protocol.
		 * With UDP there seems to be a fourth byte for the IPA header.
		 * We attempt to detect this by checking if the length from the
		 * header + four bytes of the IPA header equals the remaining size.
		 */
		if (is_udp && (len + 4 == remaining)) {
			header_length++;
		}

		ti = proto_tree_add_protocol_format(tree, proto_ipa,
				tvb, offset, len+header_length,
				"IPA protocol ip.access, type: %s",
				val_to_str(msg_type, ipa_protocol_vals,
					"unknown 0x%02x"));
		ipa_tree = proto_item_add_subtree(ti, ett_ipa);
		proto_tree_add_item(ipa_tree, hf_ipa_data_len,
				tvb, offset, 2, ENC_BIG_ENDIAN);
		proto_tree_add_item(ipa_tree, hf_ipa_protocol,
				tvb, offset+2, 1, ENC_BIG_ENDIAN);

		next_tvb = tvb_new_subset_length(tvb, offset+header_length, len);

		switch (msg_type) {
		case ABISIP_OML:
			/* hand this off to the standard A-bis OML dissector */
			if (sub_handles[SUB_OML])
				call_dissector(sub_handles[SUB_OML], next_tvb,
						 pinfo, tree);
			break;
		case ABISIP_IPACCESS:
			dissect_ipaccess(next_tvb, pinfo, tree);
			break;
		case AIP_SCCP:
			/* hand this off to the standard SCCP dissector */
			call_dissector(sub_handles[SUB_SCCP], next_tvb, pinfo, tree);
			break;
		case IPA_MGCP:
			/* hand this off to the standard MGCP dissector */
			call_dissector(sub_handles[SUB_MGCP], next_tvb, pinfo, tree);
			break;
		case OSMO_EXT:
			dissect_osmo(next_tvb, pinfo, ipa_tree, tree, ti);
			break;
		case HSL_DEBUG:
			proto_tree_add_item(ipa_tree, hf_ipa_hsl_debug,
					next_tvb, 0, len, ENC_ASCII|ENC_NA);
			if (global_ipa_in_root == TRUE)
				proto_tree_add_item(tree, hf_ipa_hsl_debug,
						next_tvb, 0, len, ENC_ASCII|ENC_NA);
			if (global_ipa_in_info == TRUE)
				col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
						tvb_get_stringz_enc(wmem_packet_scope(), next_tvb, 0, NULL, ENC_ASCII));
			break;
		default:
			if (msg_type < ABISIP_RSL_MAX) {
				/* hand this off to the standard A-bis RSL dissector */
				call_dissector(sub_handles[SUB_RSL], next_tvb, pinfo, tree);
			}
			break;
		}
		offset += len + header_length;
	}
}

static int
dissect_ipa_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
	dissect_ipa(tvb, pinfo, tree, FALSE);
	return tvb_captured_length(tvb);
}

static int
dissect_ipa_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
	dissect_ipa(tvb, pinfo, tree, TRUE);
	return tvb_captured_length(tvb);
}

void proto_register_ipa(void)
{
	module_t *ipa_module;

	static hf_register_info hf[] = {
		{&hf_ipa_data_len,
		 {"DataLen", "gsm_ipa.data_len",
		  FT_UINT16, BASE_DEC, NULL, 0x0,
		  "The length of the data (in bytes)", HFILL}
		 },
		{&hf_ipa_protocol,
		 {"Protocol", "gsm_ipa.protocol",
		  FT_UINT8, BASE_HEX, VALS(ipa_protocol_vals), 0x0,
		  "The IPA Sub-Protocol", HFILL}
		 },
		{&hf_ipa_hsl_debug,
		 {"Debug Message", "gsm_ipa.hsl_debug",
		  FT_STRING, BASE_NONE, NULL, 0,
		  "Hay Systems Limited debug message", HFILL}
		},
		{&hf_ipa_osmo_proto,
		 {"Osmo ext protocol", "gsm_ipa.osmo.protocol",
		  FT_UINT8, BASE_HEX, VALS(ipa_osmo_proto_vals), 0x0,
		  "The osmo extension protocol", HFILL}
		},

		{&hf_ipa_osmo_ctrl_data,
		 {"CTRL data", "gsm_ipa.ctrl.data",
		  FT_STRING, BASE_NONE, NULL, 0x0,
		  "Control interface data", HFILL}
		},

	};
	static hf_register_info hf_ipa[] = {
		{&hf_ipaccess_msgtype,
		 {"MessageType", "ipaccess.msg_type",
		  FT_UINT8, BASE_HEX, VALS(ipaccess_msgtype_vals), 0x0,
		  "Type of ip.access message", HFILL}
		 },
		{&hf_ipaccess_attr_tag,
		 {"Tag", "ipaccess.attr_tag",
		  FT_UINT8, BASE_HEX, VALS(ipaccess_idtag_vals), 0x0,
		  "Attribute Tag", HFILL}
		 },
		{&hf_ipaccess_attr_string,
		 {"String", "ipaccess.attr_string",
		  FT_STRING, BASE_NONE, NULL, 0x0,
		  "String attribute", HFILL}
		 },
		{&hf_ipaccess_attribute_unk,
		 {"Unknown attribute type", "ipaccess.attr_unk",
		  FT_UINT8, BASE_HEX, NULL, 0x0,
		  NULL, HFILL}
		 },
	};

	static gint *ett[] = {
		&ett_ipa,
		&ett_ipaccess,
	};

	proto_ipa = proto_register_protocol("GSM over IP protocol as used by ip.access", "GSM over IP", "gsm_ipa");
	proto_ipaccess = proto_register_protocol("GSM over IP ip.access CCM sub-protocol", "IPA", "ipaccess");

	proto_register_field_array(proto_ipa, hf, array_length(hf));
	proto_register_field_array(proto_ipaccess, hf_ipa, array_length(hf_ipa));
	proto_register_subtree_array(ett, array_length(ett));

	/* Register table for subdissectors */
	osmo_dissector_table = register_dissector_table("ipa.osmo.protocol",
					"GSM over IP ip.access Protocol", proto_ipa,
					FT_UINT8, BASE_DEC);

	ipa_module = prefs_register_protocol(proto_ipa, NULL);

	prefs_register_bool_preference(ipa_module, "hsl_debug_in_root_tree",
					"HSL Debug messages in root protocol tree",
					NULL, &global_ipa_in_root);
	prefs_register_bool_preference(ipa_module, "hsl_debug_in_info",
					"HSL Debug messages in INFO column",
					NULL, &global_ipa_in_info);
}

void proto_reg_handoff_gsm_ipa(void)
{
	sub_handles[SUB_RSL] = find_dissector_add_dependency("gsm_abis_rsl", proto_ipa);
	sub_handles[SUB_OML] = find_dissector_add_dependency("gsm_abis_oml", proto_ipa);
	sub_handles[SUB_SCCP] = find_dissector_add_dependency("sccp", proto_ipa);
	sub_handles[SUB_MGCP] = find_dissector_add_dependency("mgcp", proto_ipa);
	sub_handles[SUB_DATA] = find_dissector("data");

	ipa_tcp_handle = create_dissector_handle(dissect_ipa_tcp, proto_ipa);
	ipa_udp_handle = create_dissector_handle(dissect_ipa_udp, proto_ipa);
	dissector_add_uint_range_with_preference("tcp.port", IPA_TCP_PORTS, ipa_tcp_handle);
	dissector_add_uint_range_with_preference("udp.port", "", ipa_udp_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:
 */