aboutsummaryrefslogtreecommitdiffstats
path: root/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
blob: cc7d4428753ca2e05c213466a765ca8ffcb568df (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
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
/* BSC Multiplexer/NAT Utilities */

/*
 * (C) 2010-2011 by Holger Hans Peter Freyther <zecke@selfish.org>
 * (C) 2010-2011 by On-Waves
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation; either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <openbsc/bsc_nat.h>
#include <openbsc/bsc_nat_sccp.h>
#include <openbsc/bsc_msg_filter.h>
#include <openbsc/bsc_msc.h>
#include <openbsc/gsm_data.h>
#include <openbsc/debug.h>
#include <openbsc/ipaccess.h>
#include <openbsc/vty.h>

#include <osmocom/core/linuxlist.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/stats.h>
#include <osmocom/gsm/gsm0808.h>
#include <osmocom/gsm/ipa.h>

#include <osmocom/gsm/protocol/gsm_08_08.h>
#include <osmocom/gsm/protocol/gsm_04_11.h>

#include <osmocom/sccp/sccp.h>

#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>

static const struct rate_ctr_desc bsc_cfg_ctr_description[] = {
	[BCFG_CTR_SCCP_CONN]     = { "sccp.conn",      "SCCP Connections         "},
	[BCFG_CTR_SCCP_CALLS]    = { "sccp.calls",     "SCCP Assignment Commands "},
	[BCFG_CTR_NET_RECONN]    = { "net.reconnects", "Network reconnects       "},
	[BCFG_CTR_DROPPED_SCCP]  = { "dropped.sccp",   "Dropped SCCP connections."},
	[BCFG_CTR_DROPPED_CALLS] = { "dropped.calls",  "Dropped active calls.    "},
	[BCFG_CTR_REJECTED_CR]   = { "rejected.cr",    "Rejected CR due filter   "},
	[BCFG_CTR_REJECTED_MSG]  = { "rejected.msg",   "Rejected MSG due filter  "},
	[BCFG_CTR_ILL_PACKET]    = { "rejected.ill",   "Rejected due parse error "},
	[BCFG_CTR_CON_TYPE_LU]   = { "conn.lu",        "Conn Location Update     "},
	[BCFG_CTR_CON_CMSERV_RQ] = { "conn.rq",        "Conn CM Service Req      "},
	[BCFG_CTR_CON_PAG_RESP]  = { "conn.pag",       "Conn Paging Response     "},
	[BCFG_CTR_CON_SSA]       = { "conn.ssa",       "Conn USSD                "},
	[BCFG_CTR_CON_OTHER]     = { "conn.other",     "Conn Other               "},
};

static const struct rate_ctr_group_desc bsc_cfg_ctrg_desc = {
	.group_name_prefix = "nat.bsc",
	.group_description = "NAT BSC Statistics",
	.num_ctr = ARRAY_SIZE(bsc_cfg_ctr_description),
	.ctr_desc = bsc_cfg_ctr_description,
	.class_id = OSMO_STATS_CLASS_PEER,
};

struct bsc_nat *bsc_nat_alloc(void)
{
	struct bsc_nat *nat = talloc_zero(tall_bsc_ctx, struct bsc_nat);
	if (!nat)
		return NULL;

	nat->main_dest = talloc_zero(nat, struct bsc_msc_dest);
	if (!nat->main_dest) {
		talloc_free(nat);
		return NULL;
	}

	INIT_LLIST_HEAD(&nat->sccp_connections);
	INIT_LLIST_HEAD(&nat->bsc_connections);
	INIT_LLIST_HEAD(&nat->paging_groups);
	INIT_LLIST_HEAD(&nat->bsc_configs);
	INIT_LLIST_HEAD(&nat->access_lists);
	INIT_LLIST_HEAD(&nat->dests);
	INIT_LLIST_HEAD(&nat->num_rewr);
	INIT_LLIST_HEAD(&nat->num_rewr_post);
	INIT_LLIST_HEAD(&nat->smsc_rewr);
	INIT_LLIST_HEAD(&nat->tpdest_match);
	INIT_LLIST_HEAD(&nat->sms_clear_tp_srr);
	INIT_LLIST_HEAD(&nat->sms_num_rewr);

	nat->stats.sccp.conn = osmo_counter_alloc("nat.sccp.conn");
	nat->stats.sccp.calls = osmo_counter_alloc("nat.sccp.calls");
	nat->stats.bsc.reconn = osmo_counter_alloc("nat.bsc.conn");
	nat->stats.bsc.auth_fail = osmo_counter_alloc("nat.bsc.auth_fail");
	nat->stats.msc.reconn = osmo_counter_alloc("nat.msc.conn");
	nat->stats.ussd.reconn = osmo_counter_alloc("nat.ussd.conn");
	nat->auth_timeout = 2;
	nat->ping_timeout = 20;
	nat->pong_timeout = 5;

	llist_add(&nat->main_dest->list, &nat->dests);
	nat->main_dest->ip = talloc_strdup(nat, "127.0.0.1");
	nat->main_dest->port = 5000;

	return nat;
}

void bsc_nat_free(struct bsc_nat *nat)
{
	struct bsc_config *cfg, *tmp;
	struct bsc_msg_acc_lst *lst, *tmp_lst;

	llist_for_each_entry_safe(cfg, tmp, &nat->bsc_configs, entry)
		bsc_config_free(cfg);
	llist_for_each_entry_safe(lst, tmp_lst, &nat->access_lists, list)
		bsc_msg_acc_lst_delete(lst);

	bsc_nat_num_rewr_entry_adapt(nat, &nat->num_rewr, NULL);
	bsc_nat_num_rewr_entry_adapt(nat, &nat->num_rewr_post, NULL);
	bsc_nat_num_rewr_entry_adapt(nat, &nat->sms_clear_tp_srr, NULL);
	bsc_nat_num_rewr_entry_adapt(nat, &nat->sms_num_rewr, NULL);
	bsc_nat_num_rewr_entry_adapt(nat, &nat->tpdest_match, NULL);

	osmo_counter_free(nat->stats.sccp.conn);
	osmo_counter_free(nat->stats.sccp.calls);
	osmo_counter_free(nat->stats.bsc.reconn);
	osmo_counter_free(nat->stats.bsc.auth_fail);
	osmo_counter_free(nat->stats.msc.reconn);
	osmo_counter_free(nat->stats.ussd.reconn);
	talloc_free(nat->mgcp_cfg);
	talloc_free(nat);
}

void bsc_nat_set_msc_ip(struct bsc_nat *nat, const char *ip)
{
	bsc_replace_string(nat, &nat->main_dest->ip, ip);
}

struct bsc_connection *bsc_connection_alloc(struct bsc_nat *nat)
{
	struct bsc_connection *con = talloc_zero(nat, struct bsc_connection);
	if (!con)
		return NULL;

	con->nat = nat;
	osmo_wqueue_init(&con->write_queue, 100);
	INIT_LLIST_HEAD(&con->cmd_pending);
	INIT_LLIST_HEAD(&con->pending_dlcx);
	return con;
}

struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token)
{
	struct bsc_config *conf = talloc_zero(nat, struct bsc_config);
	if (!conf)
		return NULL;

	conf->token = talloc_strdup(conf, token);
	conf->nr = nat->num_bsc;
	conf->nat = nat;
	conf->max_endpoints = 32;
	conf->paging_group = PAGIN_GROUP_UNASSIGNED;

	INIT_LLIST_HEAD(&conf->lac_list);

	llist_add_tail(&conf->entry, &nat->bsc_configs);
	++nat->num_bsc;

	conf->stats.ctrg = rate_ctr_group_alloc(conf, &bsc_cfg_ctrg_desc, conf->nr);
	if (!conf->stats.ctrg) {
		llist_del(&conf->entry);
		talloc_free(conf);
		return NULL;
	}

	return conf;
}

struct bsc_config *bsc_config_by_token(struct bsc_nat *nat, const char *token, int len)
{
	struct bsc_config *conf;

	llist_for_each_entry(conf, &nat->bsc_configs, entry) {
		/*
		 * Add the '\0' of the token for the memcmp, the IPA messages
		 * for some reason added null termination.
		 */
		const int token_len = strlen(conf->token) + 1;

		if (token_len == len && memcmp(conf->token, token, token_len) == 0)
			return conf;
	}

	return NULL;
}

void bsc_config_free(struct bsc_config *cfg)
{
	llist_del(&cfg->entry);
	rate_ctr_group_free(cfg->stats.ctrg);
	talloc_free(cfg);
}

static void _add_lac(void *ctx, struct llist_head *list, int _lac)
{
	struct bsc_lac_entry *lac;

	llist_for_each_entry(lac, list, entry)
		if (lac->lac == _lac)
			return;

	lac = talloc_zero(ctx, struct bsc_lac_entry);
	if (!lac) {
		LOGP(DNAT, LOGL_ERROR, "Failed to allocate.\n");
		return;
	}

	lac->lac = _lac;
	llist_add_tail(&lac->entry, list);
}

static void _del_lac(struct llist_head *list, int _lac)
{
	struct bsc_lac_entry *lac;

	llist_for_each_entry(lac, list, entry)
		if (lac->lac == _lac) {
			llist_del(&lac->entry);
			talloc_free(lac);
			return;
		}
}

void bsc_config_add_lac(struct bsc_config *cfg, int _lac)
{
	_add_lac(cfg, &cfg->lac_list, _lac);
}

void bsc_config_del_lac(struct bsc_config *cfg, int _lac)
{
	_del_lac(&cfg->lac_list, _lac);
}

struct bsc_nat_paging_group *bsc_nat_paging_group_create(struct bsc_nat *nat, int group)
{
	struct bsc_nat_paging_group *pgroup;

	pgroup = talloc_zero(nat, struct bsc_nat_paging_group);
	if (!pgroup) {
		LOGP(DNAT, LOGL_ERROR, "Failed to allocate a paging group.\n");
		return NULL;
	}

	pgroup->nr = group;
	INIT_LLIST_HEAD(&pgroup->lists);
	llist_add_tail(&pgroup->entry, &nat->paging_groups);
	return pgroup;
}

void bsc_nat_paging_group_delete(struct bsc_nat_paging_group *pgroup)
{
	llist_del(&pgroup->entry);
	talloc_free(pgroup);
}

struct bsc_nat_paging_group *bsc_nat_paging_group_num(struct bsc_nat *nat, int group)
{
	struct bsc_nat_paging_group *pgroup;

	llist_for_each_entry(pgroup, &nat->paging_groups, entry)
		if (pgroup->nr == group)
			return pgroup;

	return NULL;
}

void bsc_nat_paging_group_add_lac(struct bsc_nat_paging_group *pgroup, int lac)
{
	_add_lac(pgroup, &pgroup->lists, lac);
}

void bsc_nat_paging_group_del_lac(struct bsc_nat_paging_group *pgroup, int lac)
{
	_del_lac(&pgroup->lists, lac);
}

int bsc_config_handles_lac(struct bsc_config *cfg, int lac_nr)
{
	struct bsc_nat_paging_group *pgroup;
	struct bsc_lac_entry *entry;

	llist_for_each_entry(entry, &cfg->lac_list, entry)
		if (entry->lac == lac_nr)
			return 1;

	/* now lookup the paging group */
	pgroup = bsc_nat_paging_group_num(cfg->nat, cfg->paging_group);
	if (!pgroup)
		return 0;

	llist_for_each_entry(entry, &pgroup->lists, entry)
		if (entry->lac == lac_nr)
			return 1;

	return 0;
}

void sccp_connection_destroy(struct nat_sccp_connection *conn)
{
	LOGP(DNAT, LOGL_DEBUG, "Destroy 0x%x <-> 0x%x mapping for con %p\n",
	     sccp_src_ref_to_int(&conn->real_ref),
	     sccp_src_ref_to_int(&conn->patched_ref), conn->bsc);
	bsc_mgcp_dlcx(conn);
	llist_del(&conn->list_entry);
	talloc_free(conn);
}


int bsc_nat_find_paging(struct msgb *msg,
			const uint8_t **out_data, int *out_leng)
{
	int data_length;
	const uint8_t *data;
	struct tlv_parsed tp;

	if (!msg->l3h || msgb_l3len(msg) < 3) {
		LOGP(DNAT, LOGL_ERROR, "Paging message is too short.\n");
		return -1;
	}

	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 3, msgb_l3len(msg) - 3, 0, 0);
	if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST)) {
		LOGP(DNAT, LOGL_ERROR, "No CellIdentifier List inside paging msg.\n");
		return -2;
	}

	data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);
	data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);

	/* No need to try a different BSS */
	if (data[0] == CELL_IDENT_BSS) {
		return -3;
	} else if (data[0] != CELL_IDENT_LAC) {
		LOGP(DNAT, LOGL_ERROR, "Unhandled cell ident discrminator: %d\n", data[0]);
		return -4;
	}

	*out_data = &data[1];
	*out_leng = data_length - 1;
	return 0;
}

int bsc_write_mgcp(struct bsc_connection *bsc, const uint8_t *data, unsigned int length)
{
	struct msgb *msg;

	if (length > 4096 - 128) {
		LOGP(DLINP, LOGL_ERROR, "Can not send message of that size.\n");
		return -1;
	}

	msg = msgb_alloc_headroom(4096, 128, "to-bsc");
	if (!msg) {
		LOGP(DLINP, LOGL_ERROR, "Failed to allocate memory for BSC msg.\n");
		return -1;
	}

	/* copy the data */
	msg->l3h = msgb_put(msg, length);
	memcpy(msg->l3h, data, length);

        return bsc_write(bsc, msg, IPAC_PROTO_MGCP_OLD);
}

int bsc_write(struct bsc_connection *bsc, struct msgb *msg, int proto)
{
	return bsc_do_write(&bsc->write_queue, msg, proto);
}

int bsc_do_write(struct osmo_wqueue *queue, struct msgb *msg, int proto)
{
	/* prepend the header */
	ipa_prepend_header(msg, proto);
	return bsc_write_msg(queue, msg);
}

int bsc_write_msg(struct osmo_wqueue *queue, struct msgb *msg)
{
	if (osmo_wqueue_enqueue(queue, msg) != 0) {
		LOGP(DLINP, LOGL_ERROR, "Failed to enqueue the write.\n");
		msgb_free(msg);
		return -1;
	}

	return 0;
}

struct gsm48_hdr *bsc_unpack_dtap(struct bsc_nat_parsed *parsed,
				  struct msgb *msg, uint32_t *len)
{
	/* gsm_type is actually the size of the dtap */
	*len = parsed->gsm_type;
	if (*len < msgb_l3len(msg) - 3) {
		LOGP(DNAT, LOGL_ERROR, "Not enough space for DTAP.\n");
		return NULL;
	}

	if (msgb_l3len(msg) - 3 < msg->l3h[2]) {
		LOGP(DNAT, LOGL_ERROR,
		     "GSM48 payload does not fit: %d %d\n",
		     msg->l3h[2], msgb_l3len(msg) - 3);
		return NULL;
	}

	msg->l4h = &msg->l3h[3];
	return (struct gsm48_hdr *) msg->l4h;
}

static const char *con_types [] = {
	[FLT_CON_TYPE_NONE] = "n/a",
	[FLT_CON_TYPE_LU] = "Location Update",
	[FLT_CON_TYPE_CM_SERV_REQ] = "CM Serv Req",
	[FLT_CON_TYPE_PAG_RESP] = "Paging Response",
	[FLT_CON_TYPE_SSA] = "Supplementar Service Activation",
	[FLT_CON_TYPE_LOCAL_REJECT] = "Local Reject",
	[FLT_CON_TYPE_OTHER] = "Other",
};

const char *bsc_con_type_to_string(int type)
{
	return con_types[type];
}

int bsc_nat_msc_is_connected(struct bsc_nat *nat)
{
	return nat->msc_con->is_connected;
}

static const int con_to_ctr[] = {
	[FLT_CON_TYPE_NONE]		= -1,
	[FLT_CON_TYPE_LU]		= BCFG_CTR_CON_TYPE_LU,
	[FLT_CON_TYPE_CM_SERV_REQ]	= BCFG_CTR_CON_CMSERV_RQ,
	[FLT_CON_TYPE_PAG_RESP]		= BCFG_CTR_CON_PAG_RESP,
	[FLT_CON_TYPE_SSA]		= BCFG_CTR_CON_SSA,
	[FLT_CON_TYPE_LOCAL_REJECT]	= -1,
	[FLT_CON_TYPE_OTHER]		= BCFG_CTR_CON_OTHER,
};

int bsc_conn_type_to_ctr(struct nat_sccp_connection *conn)
{
	return con_to_ctr[conn->filter_state.con_type];
}

int bsc_write_cb(struct osmo_fd *bfd, struct msgb *msg)
{
	int rc;

	rc = write(bfd->fd, msg->data, msg->len);
	if (rc != msg->len)
		LOGP(DNAT, LOGL_ERROR, "Failed to write message to the BSC.\n");

	return rc;
}

static void extract_lac(const uint8_t *data, uint16_t *lac, uint16_t *ci)
{
	memcpy(lac, &data[0], sizeof(*lac));
	memcpy(ci, &data[2], sizeof(*ci));

	*lac = ntohs(*lac);
	*ci = ntohs(*ci);
}

int bsc_nat_extract_lac(struct bsc_connection *bsc,
			struct nat_sccp_connection *con,
			struct bsc_nat_parsed *parsed, struct msgb *msg)
{
	int data_length;
	const uint8_t *data;
	struct tlv_parsed tp;
	uint16_t lac, ci;

	if (parsed->gsm_type != BSS_MAP_MSG_COMPLETE_LAYER_3) {
		LOGP(DNAT, LOGL_ERROR, "Can only extract LAC from Complete Layer3\n");
		return -1;
	}

	if (!msg->l3h || msgb_l3len(msg) < 3) {
		LOGP(DNAT, LOGL_ERROR, "Complete Layer3 mssage is too short.\n");
		return -1;
	}

	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 3, msgb_l3len(msg) - 3, 0, 0);
	if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER)) {
		LOGP(DNAT, LOGL_ERROR, "No CellIdentifier List inside paging msg.\n");
		return -2;
	}

	data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER);
	data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER);

	/* Attemt to get the LAC/CI from it */
	if (data[0] == CELL_IDENT_WHOLE_GLOBAL) {
		if (data_length != 8) {
			LOGP(DNAT, LOGL_ERROR,
				"Ident too short: %d\n", data_length);
			return -3;
		}
		extract_lac(&data[1 + 3], &lac, &ci);
	} else if (data[0] == CELL_IDENT_LAC_AND_CI) {
		if (data_length != 5) {
			LOGP(DNAT, LOGL_ERROR,
				"Ident too short: %d\n", data_length);
			return -3;
		}
		extract_lac(&data[1], &lac, &ci);
	} else {
		LOGP(DNAT, LOGL_ERROR,
			"Unhandled cell identifier: %d\n", data[0]);
		return -1;
	}

	con->lac = lac;
	con->ci = ci;
	return 0;
}