aboutsummaryrefslogtreecommitdiffstats
path: root/src/osmo-bsc/osmo_bsc_sigtran.c
blob: 2ba777ed92e9f681db574ba3aa6f5128951c8d9c (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
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
/* (C) 2017 by sysmocom s.f.m.c. GmbH
 * All Rights Reserved
 *
 * Author: Philipp Maier
 *
 * 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 <osmocom/core/utils.h>
#include <osmocom/core/logging.h>
#include <osmocom/sigtran/osmo_ss7.h>
#include <osmocom/sigtran/sccp_sap.h>
#include <osmocom/sccp/sccp_types.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/gsm/gsm0808.h>
#include <osmocom/core/msgb.h>
#include <osmocom/bsc/bsc_msc_data.h>
#include <osmocom/bsc/debug.h>
#include <osmocom/bsc/osmo_bsc.h>
#include <osmocom/bsc/osmo_bsc_grace.h>
#include <osmocom/bsc/osmo_bsc_sigtran.h>
#include <osmocom/bsc/a_reset.h>
#include <osmocom/bsc/gsm_04_80.h>
#include <osmocom/bsc/osmo_bsc_mgcp.h>

/* A pointer to a list with all involved MSCs
 * (a copy of the pointer location submitted with osmo_bsc_sigtran_init() */
static struct llist_head *msc_list;

#define RESET_INTERVAL 1	/* sek */
#define SCCP_MSG_MAXSIZE 1024
#define CS7_POINTCODE_DEFAULT_OFFSET 2

/* Internal list with connections we currently maintain. This
 * list is of type struct osmo_bsc_sccp_con */
static LLIST_HEAD(active_connections);

/* The SCCP stack will not assign connection IDs to us automatically, we
 * will do this ourselves using a counter variable, that counts one up
 * for every new connection */
static uint32_t conn_id_counter;

/* Helper function to Check if the given connection id is already assigned */
static struct osmo_bsc_sccp_con *get_bsc_conn_by_conn_id(int conn_id)
{
	conn_id &= 0xFFFFFF;
	struct osmo_bsc_sccp_con *bsc_con;

	llist_for_each_entry(bsc_con, &active_connections, entry) {
		if (bsc_con->conn_id == conn_id)
			return bsc_con;
	}

	return NULL;
}

/* Pick a free connection id */
static int pick_free_conn_id(const struct bsc_msc_data *msc)
{
	int conn_id = conn_id_counter;
	int i;

	for (i = 0; i < 0xFFFFFF; i++) {
		conn_id++;
		conn_id &= 0xFFFFFF;
		if (get_bsc_conn_by_conn_id(conn_id) == false) {
			conn_id_counter = conn_id;
			return conn_id;
		}
	}

	return -1;
}

/* Send reset to MSC */
static void osmo_bsc_sigtran_tx_reset(const struct bsc_msc_data *msc)
{
	struct osmo_ss7_instance *ss7;
	struct msgb *msg;

	ss7 = osmo_ss7_instance_find(msc->a.cs7_instance);
	OSMO_ASSERT(ss7);
	LOGP(DMSC, LOGL_NOTICE, "Sending RESET to MSC: %s\n", osmo_sccp_addr_name(ss7, &msc->a.msc_addr));
	msg = gsm0808_create_reset();
	osmo_sccp_tx_unitdata_msg(msc->a.sccp_user, &msc->a.bsc_addr,
				  &msc->a.msc_addr, msg);
}

/* Send reset-ack to MSC */
void osmo_bsc_sigtran_tx_reset_ack(const struct bsc_msc_data *msc)
{
	struct osmo_ss7_instance *ss7;
	struct msgb *msg;
	OSMO_ASSERT(msc);

	ss7 = osmo_ss7_instance_find(msc->a.cs7_instance);
	OSMO_ASSERT(ss7);
	LOGP(DMSC, LOGL_NOTICE, "Sending RESET ACK to MSC: %s\n", osmo_sccp_addr_name(ss7, &msc->a.msc_addr));
	msg = gsm0808_create_reset_ack();
	osmo_sccp_tx_unitdata_msg(msc->a.sccp_user, &msc->a.bsc_addr,
				  &msc->a.msc_addr, msg);
}

/* Find an MSC by its sigtran point code */
static struct bsc_msc_data *get_msc_by_addr(const struct osmo_sccp_addr *msc_addr)
{
	struct osmo_ss7_instance *ss7;
	struct bsc_msc_data *msc;
	llist_for_each_entry(msc, msc_list, entry) {
		if (memcmp(msc_addr, &msc->a.msc_addr, sizeof(*msc_addr)) == 0)
			return msc;
	}

	ss7 = osmo_ss7_instance_find(msc->a.cs7_instance);
	OSMO_ASSERT(ss7);
	LOGP(DMSC, LOGL_ERROR, "Unable to find MSC data under address: %s\n", osmo_sccp_addr_name(ss7, msc_addr));
	return NULL;
}

/* Send data to MSC, use the connection id which MSC it is */
static int handle_data_from_msc(int conn_id, struct msgb *msg)
{
	struct osmo_bsc_sccp_con *bsc_con = get_bsc_conn_by_conn_id(conn_id);
	int rc = -EINVAL;

	if (bsc_con) {
		msg->l3h = msgb_l2(msg);
		rc = bsc_handle_dt(bsc_con, msg, msgb_l2len(msg));
	} else
		LOGP(DMSC, LOGL_NOTICE, "incoming data from unknown connection id: %i\n", conn_id);

	return rc;
}

/* Sent unitdata to MSC, use the point code to determine which MSC it is */
static int handle_unitdata_from_msc(const struct osmo_sccp_addr *msc_addr, struct msgb *msg,
				    const struct osmo_sccp_user *scu)
{
	struct osmo_ss7_instance *ss7;
	struct bsc_msc_data *msc = get_msc_by_addr(msc_addr);
	int rc = -EINVAL;

	if (msc) {
		msg->l3h = msgb_l2(msg);
		rc = bsc_handle_udt(msc, msg, msgb_l2len(msg));
	} else {
		ss7 = osmo_sccp_get_ss7(osmo_sccp_get_sccp(scu));
		OSMO_ASSERT(ss7);
		LOGP(DMSC, LOGL_NOTICE, "incoming unitdata data from unknown remote address: %s\n",
		     osmo_sccp_addr_name(ss7, msc_addr));
	}
	return rc;
}

/* Callback function, called by the SSCP stack when data arrives */
static int sccp_sap_up(struct osmo_prim_hdr *oph, void *_scu)
{
	struct osmo_scu_prim *scu_prim = (struct osmo_scu_prim *)oph;
	struct osmo_sccp_user *scu = _scu;
	struct osmo_bsc_sccp_con *bsc_con;
	int rc = 0;

	switch (OSMO_PRIM_HDR(&scu_prim->oph)) {
	case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_INDICATION):
		/* Handle inbound UNITDATA */
		DEBUGP(DMSC, "N-UNITDATA.ind(%s)\n", osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
		rc = handle_unitdata_from_msc(&scu_prim->u.unitdata.calling_addr, oph->msg, scu);
		break;

	case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_INDICATION):
		/* Handle (Reject) inbound connections */
		DEBUGP(DMSC, "N-CONNECT.ind(X->%u)\n", scu_prim->u.connect.conn_id);
		LOGP(DMSC, LOGL_DEBUG, "Rejecting inbound SCCP connection...\n");
		rc = osmo_sccp_tx_disconn(scu, scu_prim->u.connect.conn_id, &scu_prim->u.connect.called_addr, 0);
		break;

	case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_CONFIRM):
		/* Handle outbound connection confirmation */
		if (msgb_l2len(oph->msg) > 0) {
			DEBUGP(DMSC, "N-CONNECT.cnf(%u, %s)\n", scu_prim->u.connect.conn_id,
			       osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
			rc = handle_data_from_msc(scu_prim->u.connect.conn_id, oph->msg);
		} else
			DEBUGP(DRANAP, "N-CONNECT.cnf(%u)\n", scu_prim->u.connect.conn_id);
		break;

	case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
		/* Handle incoming connection oriented data */
		DEBUGP(DMSC, "N-DATA.ind(%u, %s)\n", scu_prim->u.data.conn_id,
		       osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));

		/* Incoming data is a sign of a vital connection */
		bsc_con = get_bsc_conn_by_conn_id(scu_prim->u.disconnect.conn_id);
		if (bsc_con)
			a_reset_conn_success(bsc_con->msc->a.reset);

		rc = handle_data_from_msc(scu_prim->u.data.conn_id, oph->msg);
		break;

	case OSMO_PRIM(OSMO_SCU_PRIM_N_DISCONNECT, PRIM_OP_INDICATION):
		/* indication of disconnect */
		if (msgb_l2len(oph->msg) > 0) {
			DEBUGP(DMSC, "N-DISCONNECT.ind(%u, %s, cause=%i)\n", scu_prim->u.disconnect.conn_id,
			       osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)), scu_prim->u.disconnect.cause);
			handle_data_from_msc(scu_prim->u.disconnect.conn_id, oph->msg);
		} else
			DEBUGP(DRANAP, "N-DISCONNECT.ind(%u, cause=%i)\n", scu_prim->u.disconnect.conn_id,
			       scu_prim->u.disconnect.cause);

		bsc_con = get_bsc_conn_by_conn_id(scu_prim->u.disconnect.conn_id);
		if (bsc_con) {
			/* We might have a connectivity problem. Maybe we need to go
			 * through the reset procedure again? */
			if (scu_prim->u.disconnect.cause == 0)
				a_reset_conn_fail(bsc_con->msc->a.reset);

			rc = osmo_bsc_sigtran_del_conn(bsc_con);
		}
		break;

	default:
		LOGP(DMSC, LOGL_ERROR, "Unhandled SIGTRAN primitive: %u:%u\n", oph->primitive, oph->operation);
		break;
	}

	msgb_free(oph->msg);
	return rc;
}

/* Allocate resources to make a new connection oriented sigtran connection
 * (not the connection ittself!) */
enum bsc_con osmo_bsc_sigtran_new_conn(struct gsm_subscriber_connection *conn, struct bsc_msc_data *msc)
{
	struct osmo_ss7_instance *ss7;
	struct osmo_bsc_sccp_con *bsc_con;
	int conn_id;

	OSMO_ASSERT(conn);
	OSMO_ASSERT(msc);

	ss7 = osmo_ss7_instance_find(msc->a.cs7_instance);
	OSMO_ASSERT(ss7);
	LOGP(DMSC, LOGL_NOTICE, "Initializing resources for new SIGTRAN connection to MSC: %s...\n",
	     osmo_sccp_addr_name(ss7, &msc->a.msc_addr));

	if (a_reset_conn_ready(msc->a.reset) == false) {
		LOGP(DMSC, LOGL_ERROR, "MSC is not connected. Dropping.\n");
		return BSC_CON_REJECT_NO_LINK;
	}

	if (!bsc_grace_allow_new_connection(conn->bts->network, conn->bts)) {
		LOGP(DMSC, LOGL_NOTICE, "BSC in grace period. No new connections.\n");
		return BSC_CON_REJECT_RF_GRACE;
	}

	bsc_con = talloc_zero(conn->bts, struct osmo_bsc_sccp_con);
	if (!bsc_con) {
		LOGP(DMSC, LOGL_ERROR, "Failed to allocate new SIGTRAN connection.\n");
		return BSC_CON_NO_MEM;
	}

	bsc_con->msc = msc;
	bsc_con->conn = conn;
	llist_add_tail(&bsc_con->entry, &active_connections);
	conn->sccp_con = bsc_con;

	/* Pick a free connection id */
	conn_id = pick_free_conn_id(msc);
	if (conn_id < 0)
		return BSC_CON_REJECT_NO_LINK;
	bsc_con->conn_id = conn_id;

	LOGP(DMSC, LOGL_NOTICE, "Allocated new connection id: %i\n", conn_id);

	return BSC_CON_SUCCESS;
}

/* Open a new connection oriented sigtran connection */
int osmo_bsc_sigtran_open_conn(const struct osmo_bsc_sccp_con *conn, struct msgb *msg)
{
	struct osmo_ss7_instance *ss7;
	struct bsc_msc_data *msc;
	int conn_id;
	int rc;

	OSMO_ASSERT(conn);
	OSMO_ASSERT(msg);
	OSMO_ASSERT(conn->msc);

	msc = conn->msc;

	if (a_reset_conn_ready(msc->a.reset) == false) {
		LOGP(DMSC, LOGL_ERROR, "MSC is not connected. Dropping.\n");
		return -EINVAL;
	}

	conn_id = conn->conn_id;
	ss7 = osmo_ss7_instance_find(msc->a.cs7_instance);
	OSMO_ASSERT(ss7);
	LOGP(DMSC, LOGL_NOTICE, "Opening new SIGTRAN connection (id=%i) to MSC: %s\n", conn_id,
	     osmo_sccp_addr_name(ss7, &msc->a.msc_addr));

	rc = osmo_sccp_tx_conn_req_msg(msc->a.sccp_user, conn_id, &msc->a.bsc_addr,
				       &msc->a.msc_addr, msg);

	return rc;
}

/* Send data to MSC */
int osmo_bsc_sigtran_send(const struct osmo_bsc_sccp_con *conn, struct msgb *msg)
{
	struct osmo_ss7_instance *ss7;
	int conn_id;
	int rc;
	struct bsc_msc_data *msc;

	OSMO_ASSERT(conn);
	OSMO_ASSERT(msg);
	OSMO_ASSERT(conn->msc);

	msc = conn->msc;

	/* Log the type of the message we are sending. This is just
	 * informative, do not stop if detecting the type fails */
	if (msg->len >= 3) {
		switch (msg->data[0]) {
		case BSSAP_MSG_BSS_MANAGEMENT:
			LOGP(DMSC, LOGL_INFO, "Tx MSC %s\n", gsm0808_bssmap_name(msg->data[2]));
			break;
		case BSSAP_MSG_DTAP:
			LOGP(DMSC, LOGL_INFO, "Tx MSC DTAP\n");
			break;
		default:
			LOGP(DMSC, LOGL_ERROR, "Tx MSC (unknwon message type)\n");
		}
	} else
		LOGP(DMSC, LOGL_ERROR, "Tx MSC (message too short)\n");

	if (a_reset_conn_ready(msc->a.reset) == false) {
		LOGP(DMSC, LOGL_ERROR, "MSC is not connected. Dropping.\n");
		return -EINVAL;
	}

	conn_id = conn->conn_id;

	ss7 = osmo_ss7_instance_find(msc->a.cs7_instance);
	OSMO_ASSERT(ss7);
	LOGP(DMSC, LOGL_DEBUG, "Sending connection (id=%i) oriented data to MSC: %s (%s)\n",
	     conn_id, osmo_sccp_addr_name(ss7, &msc->a.msc_addr), osmo_hexdump(msg->data, msg->len));

	rc = osmo_sccp_tx_data_msg(msc->a.sccp_user, conn_id, msg);

	return rc;
}

/* Delete a connection from the list with open connections
 * (called by osmo_bsc_api.c on failing open connections and
 * locally, when a connection is closed by the MSC */
int osmo_bsc_sigtran_del_conn(struct osmo_bsc_sccp_con *conn)
{
	if (!conn)
		return 0;

	if (conn->conn) {
		LOGP(DMSC, LOGL_ERROR,
		     "sccp connection (id=%i) not cleared (gsm subscriber connection still active) -- forcefully clearing it now!\n",
		     conn->conn_id);
		bsc_subscr_con_free(conn->conn);
		conn->conn = NULL;

		/* This bahaviour might be caused by a bad connection. Maybe we
		 * will have to go through the reset procedure again */
		a_reset_conn_fail(conn->msc->a.reset);
	}

	/* Remove mgcp context if existant */
	if (conn->mgcp_ctx)
		mgcp_free_ctx(conn->mgcp_ctx);

	llist_del(&conn->entry);
	talloc_free(conn);

	return 0;
}

/* Send an USSD notification in case we loose the connection to the MSC */
static void bsc_notify_msc_lost(const struct osmo_bsc_sccp_con *conn)
{
	struct gsm_subscriber_connection *subscr_conn;

	/* Check if sccp conn is still present */
	if (!conn)
		return;
	subscr_conn = conn->conn;

	/* send USSD notification if string configured and conn->data is set */
	if (!subscr_conn)
		return;

	/* check for config string */
	if (!conn->msc->ussd_msc_lost_txt)
		return;
	if (conn->msc->ussd_msc_lost_txt[0] == '\0')
		return;

	/* send USSD notification */
	bsc_send_ussd_notify(subscr_conn, 1, subscr_conn->sccp_con->msc->ussd_msc_lost_txt);
	bsc_send_ussd_release_complete(subscr_conn);
}

/* Close all open sigtran connections and channels */
void osmo_bsc_sigtran_reset(const struct bsc_msc_data *msc)
{
	struct osmo_bsc_sccp_con *conn;
	struct osmo_bsc_sccp_con *conn_temp;
	OSMO_ASSERT(msc);

	/* Close all open connections */
	llist_for_each_entry_safe(conn, conn_temp, &active_connections, entry) {

		/* We only may close connections which actually belong to this
		 * MSC. All other open connections are left untouched */
		if (conn->msc == msc) {
			/* Notify active connection users via USSD that the MSC is down */
			bsc_notify_msc_lost(conn);

			/* Take down all occopied RF channels */
			if (conn->conn)
				gsm0808_clear(conn->conn);

			/* Disconnect all Sigtran connections */
			osmo_sccp_tx_disconn(msc->a.sccp_user, conn->conn_id, &msc->a.bsc_addr, 0);

			/* Delete subscriber connection */
			osmo_bsc_sigtran_del_conn(conn);
		}
	}
}

/* Callback function: Close all open connections */
static void osmo_bsc_sigtran_reset_cb(const void *priv)
{
	struct bsc_msc_data *msc = (struct bsc_msc_data*) priv;

	/* Shut down all ongoing traffic */
	osmo_bsc_sigtran_reset(msc);

	/* Send reset to MSC */
	osmo_bsc_sigtran_tx_reset(msc);
}

/* Default point-code to be used as local address (BSC) */
#define BSC_DEFAULT_PC "0.23.3"

/* Default point-code to be used as remote address (MSC) */
#define MSC_DEFAULT_PC "0.23.1"

/* Initalize osmo sigtran backhaul */
int osmo_bsc_sigtran_init(struct llist_head *mscs)
{
	bool free_attempt_used = false;
	bool fail_on_next_invalid_cfg = false;

	struct bsc_msc_data *msc;
	char msc_name[32];
	uint32_t default_pc;

	OSMO_ASSERT(mscs);
	msc_list = mscs;

	llist_for_each_entry(msc, msc_list, entry) {
		snprintf(msc_name, sizeof(msc_name), "msc-%u", msc->nr);
		LOGP(DMSC, LOGL_NOTICE, "Initializing SCCP connection to MSC %s\n", msc_name);

		/* Check if the VTY could determine a valid CS7 instance,
		 * use safe default in case none is set */
		if (msc->a.cs7_instance_valid == false) {
			msc->a.cs7_instance = 0;
			if (fail_on_next_invalid_cfg)
				goto fail_auto_cofiguration;
			free_attempt_used = true;
		}
		LOGP(DMSC, LOGL_NOTICE, "CS7 Instance identifier, A-Interface: %u\n", msc->a.cs7_instance);

		/* Pre-Check if there is an ss7 instance present */
		if (osmo_ss7_instance_find(msc->a.cs7_instance) == NULL) {
			if (fail_on_next_invalid_cfg)
				goto fail_auto_cofiguration;
			free_attempt_used = true;
		}

		/* SS7 Protocol stack */
		default_pc = osmo_ss7_pointcode_parse(NULL, BSC_DEFAULT_PC);
		msc->a.sccp =
		    osmo_sccp_simple_client_on_ss7_id(msc, msc->a.cs7_instance, msc_name, default_pc,
						      OSMO_SS7_ASP_PROT_M3UA, 0, NULL, 0, NULL);
		if (!msc->a.sccp)
			return -EINVAL;

		/* Check if the sccp-address fullfills minimum requirements (SSN+PC is present,
		 * automatically recover addresses if the addresses are not set up properly) */
		if (!osmo_sccp_check_addr(&msc->a.bsc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
			if (fail_on_next_invalid_cfg)
				goto fail_auto_cofiguration;
			free_attempt_used = true;

			LOGP(DMSC, LOGL_NOTICE,
			     "A-interface: invalid or missing local (BSC) SCCP address (a.bsc_addr=%s)\n",
			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.bsc_addr));
			osmo_sccp_local_addr_by_instance(&msc->a.bsc_addr, msc->a.sccp, SCCP_SSN_BSSAP);
			LOGP(DMSC, LOGL_NOTICE,
			     "A-interface: using automatically generated local (BSC) SCCP address (a.bsc_addr=%s)\n",
			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.bsc_addr));
		} else {
			LOGP(DMSC, LOGL_NOTICE,
			     "A-interface: using local (BSC) automatically SCCP address (a.msc_addr=%s)\n",
			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.bsc_addr));
		}

		if (!osmo_sccp_check_addr(&msc->a.msc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
			if (fail_on_next_invalid_cfg)
				goto fail_auto_cofiguration;
			free_attempt_used = true;

			LOGP(DMSC, LOGL_NOTICE,
			     "A-interface: invalid or missing remote (MSC) SCCP address for the MSC (a.msc_addr=%s)\n",
			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr));
			osmo_sccp_local_addr_by_instance(&msc->a.msc_addr, msc->a.sccp, SCCP_SSN_BSSAP);
			msc->a.msc_addr.pc = osmo_ss7_pointcode_parse(NULL, MSC_DEFAULT_PC);
			LOGP(DMSC, LOGL_NOTICE,
			     "A-interface: using automatically generated remote (MSC) SCCP address (a.msc_addr=%s)\n",
			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr));
			free_attempt_used = true;
		} else {
			LOGP(DMSC, LOGL_NOTICE,
			     "A-interface: using remote (MSC) automatically SCCP address (a.msc_addr=%s)\n",
			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr));
		}

		/* Bind SCCP user */
		msc->a.sccp_user = osmo_sccp_user_bind(msc->a.sccp, msc_name, sccp_sap_up, msc->a.bsc_addr.ssn);
		if (!msc->a.sccp_user)
			return -EINVAL;

		/* Start MSC-Reset procedure */
		msc->a.reset = a_reset_alloc(msc, msc_name, osmo_bsc_sigtran_reset_cb, msc);
		if (!msc->a.reset)
			return -EINVAL;

		/* If we have detected that the SS7 configuration of the MSC we have just initalized
		 * was incomplete or completely missing, we can not tolerate another incomplete
		 * configuration. The reson for this is that we do only specify exactly one default
		 * pointcode pair. We also specify localhost as default IP-Address. If we have wanted
		 * to support multiple MSCs with automatic configuration we would be forced to invent
		 * a complex ruleset how to allocate the pointcodes and respective IP-Addresses.
		 * Furthermore, the situation where a single BSC is connected to multiple MSCs
		 * is a very rare situation anyway. In this case we expect the user to experienced
		 * enough to create a valid SS7/CS7 VTY configuration that does not lack any
		 * components */
		if (free_attempt_used)
			fail_on_next_invalid_cfg = true;
	}

	return 0;

fail_auto_cofiguration:
	LOGP(DMSC, LOGL_ERROR,
	     "A-interface: More than one invalid/inclomplete configuration detected, unable to revover - check config file!\n");
	return -EINVAL;
}