summaryrefslogtreecommitdiffstats
path: root/src/gb/gprs_bssgp_bss.c
blob: f06c403f410c2439fb7c7280ca9538e63177bfbb (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
/*! \file gprs_bssgp_bss.c
 * GPRS BSSGP protocol implementation as per 3GPP TS 08.18. */
/*
 * (C) 2009-2017 by Harald Welte <laforge@gnumonks.org>
 *
 * All Rights Reserved
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <errno.h>
#include <stdint.h>

#include <osmocom/core/msgb.h>
#include <osmocom/core/byteswap.h>
#include <osmocom/core/rate_ctr.h>
#include <osmocom/gsm/tlv.h>
#include <osmocom/core/talloc.h>
#include <osmocom/gprs/gprs_bssgp.h>
#include <osmocom/gprs/gprs_bssgp_bss.h>
#include <osmocom/gprs/gprs_ns.h>

#include "common_vty.h"

#define GSM_IMSI_LENGTH 17

uint8_t *bssgp_msgb_tlli_put(struct msgb *msg, uint32_t tlli)
{
	uint32_t _tlli = osmo_htonl(tlli);
	return msgb_tvlv_put(msg, BSSGP_IE_TLLI, 4, (uint8_t *) &_tlli);
}

uint8_t *bssgp_msgb_ra_put(struct msgb *msg, const struct gprs_ra_id *ra_id)
{
	struct gsm48_ra_id ra;

	gsm48_encode_ra(&ra, ra_id);
	return msgb_tvlv_put(msg, BSSGP_IE_ROUTEING_AREA, sizeof(ra), (const uint8_t *)&ra);
}

/*! GMM-SUSPEND.req (Chapter 10.3.6) */
int bssgp_tx_suspend(uint16_t nsei, uint32_t tlli,
		     const struct gprs_ra_id *ra_id)
{
	struct msgb *msg = bssgp_msgb_alloc();
	struct bssgp_normal_hdr *bgph =
			(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));

	LOGP(DBSSGP, LOGL_NOTICE, "BSSGP (BVCI=0) Tx SUSPEND (TLLI=0x%04x)\n",
		tlli);
	msgb_nsei(msg) = nsei;
	msgb_bvci(msg) = 0; /* Signalling */
	bgph->pdu_type = BSSGP_PDUT_SUSPEND;

	bssgp_msgb_tlli_put(msg, tlli);
	bssgp_msgb_ra_put(msg, ra_id);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! GMM-RESUME.req (Chapter 10.3.9) */
int bssgp_tx_resume(uint16_t nsei, uint32_t tlli,
		    const struct gprs_ra_id *ra_id, uint8_t suspend_ref)
{
	struct msgb *msg = bssgp_msgb_alloc();
	struct bssgp_normal_hdr *bgph =
			(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));

	LOGP(DBSSGP, LOGL_NOTICE, "BSSGP (BVCI=0) Tx RESUME (TLLI=0x%04x)\n",
		tlli);
	msgb_nsei(msg) = nsei;
	msgb_bvci(msg) = 0; /* Signalling */
	bgph->pdu_type = BSSGP_PDUT_RESUME;

	bssgp_msgb_tlli_put(msg, tlli);
	bssgp_msgb_ra_put(msg, ra_id);

	msgb_tvlv_put(msg, BSSGP_IE_SUSPEND_REF_NR, 1, &suspend_ref);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! Transmit RA-CAPABILITY-UPDATE (10.3.3) */
int bssgp_tx_ra_capa_upd(struct bssgp_bvc_ctx *bctx, uint32_t tlli, uint8_t tag)
{
	struct msgb *msg = bssgp_msgb_alloc();
	struct bssgp_normal_hdr *bgph =
		(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));

	LOGP(DBSSGP, LOGL_NOTICE, "BSSGP (BVCI=%u) Tx RA-CAPA-UPD (TLLI=0x%04x)\n",
		bctx->bvci, tlli);

	/* set NSEI and BVCI in msgb cb */
	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = bctx->bvci;

	bgph->pdu_type = BSSGP_PDUT_RA_CAPA_UDPATE;
	bssgp_msgb_tlli_put(msg, tlli);

	msgb_tvlv_put(msg, BSSGP_IE_TAG, 1, &tag);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/* first common part of RADIO-STATUS */
static struct msgb *common_tx_radio_status(struct bssgp_bvc_ctx *bctx)
{
	struct msgb *msg = bssgp_msgb_alloc();
	struct bssgp_normal_hdr *bgph =
		(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));

	LOGP(DBSSGP, LOGL_NOTICE, "BSSGP (BVCI=%u) Tx RADIO-STATUS ",
		bctx->bvci);

	/* set NSEI and BVCI in msgb cb */
	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = bctx->bvci;

	bgph->pdu_type = BSSGP_PDUT_RADIO_STATUS;

	return msg;
}

/* second common part of RADIO-STATUS */
static int common_tx_radio_status2(struct msgb *msg, uint8_t cause)
{
	msgb_tvlv_put(msg, BSSGP_IE_CAUSE, 1, &cause);
	LOGPC(DBSSGP, LOGL_NOTICE, "CAUSE=%s\n", bssgp_cause_str(cause));

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! Transmit RADIO-STATUS for TLLI (10.3.5) */
int bssgp_tx_radio_status_tlli(struct bssgp_bvc_ctx *bctx, uint8_t cause,
				uint32_t tlli)
{
	struct msgb *msg = common_tx_radio_status(bctx);

	if (!msg)
		return -ENOMEM;
	bssgp_msgb_tlli_put(msg, tlli);
	LOGPC(DBSSGP, LOGL_NOTICE, "TLLI=0x%08x ", tlli);

	return common_tx_radio_status2(msg, cause);
}

/*! Transmit RADIO-STATUS for TMSI (10.3.5) */
int bssgp_tx_radio_status_tmsi(struct bssgp_bvc_ctx *bctx, uint8_t cause,
				uint32_t tmsi)
{
	struct msgb *msg = common_tx_radio_status(bctx);
	uint32_t _tmsi = osmo_htonl(tmsi);

	if (!msg)
		return -ENOMEM;
	msgb_tvlv_put(msg, BSSGP_IE_TMSI, 4, (uint8_t *)&_tmsi);
	LOGPC(DBSSGP, LOGL_NOTICE, "TMSI=0x%08x ", tmsi);

	return common_tx_radio_status2(msg, cause);
}

/*! Transmit RADIO-STATUS for IMSI (10.3.5) */
int bssgp_tx_radio_status_imsi(struct bssgp_bvc_ctx *bctx, uint8_t cause,
				const char *imsi)
{
	struct msgb *msg = common_tx_radio_status(bctx);
	uint8_t mi[GSM48_MID_MAX_SIZE];
	int imsi_len = gsm48_generate_mid_from_imsi(mi, imsi);

	if (!msg)
		return -ENOMEM;
/* gsm48_generate_mid_from_imsi() is guaranteed to never return more than 11,
 * but somehow gcc (8.2) is not smart enough to figure this out and claims that
 * the memcpy in msgb_tvlv_put() below will cause and out-of-bounds access up to
 * mi[131], which is wrong */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Warray-bounds"
	/* strip the MI type and length values (2 bytes) */
	if (imsi_len > 2)
		msgb_tvlv_put(msg, BSSGP_IE_IMSI, imsi_len-2, mi+2);
#pragma GCC diagnostic pop
	LOGPC(DBSSGP, LOGL_NOTICE, "IMSI=%s ", imsi);

	return common_tx_radio_status2(msg, cause);
}

/*! Transmit FLUSH-LL-ACK (Chapter 10.4.2) */
int bssgp_tx_flush_ll_ack(struct bssgp_bvc_ctx *bctx, uint32_t tlli,
			   uint8_t action, uint16_t bvci_new,
			   uint32_t num_octets)
{
	struct msgb *msg = bssgp_msgb_alloc();
	struct bssgp_normal_hdr *bgph =
			(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
	uint16_t _bvci_new = osmo_htons(bvci_new);
	uint32_t _oct_aff = osmo_htonl(num_octets & 0xFFFFFF);

	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = 0; /* Signalling */
	bgph->pdu_type = BSSGP_PDUT_FLUSH_LL_ACK;

	bssgp_msgb_tlli_put(msg, tlli);
	msgb_tvlv_put(msg, BSSGP_IE_FLUSH_ACTION, 1, &action);
	if (action == 1) /* transferred */
		msgb_tvlv_put(msg, BSSGP_IE_BVCI, 2, (uint8_t *) &_bvci_new);
	msgb_tvlv_put(msg, BSSGP_IE_NUM_OCT_AFF, 3, (uint8_t *) &_oct_aff);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! Transmit LLC-DISCARDED (Chapter 10.4.3) */
int bssgp_tx_llc_discarded(struct bssgp_bvc_ctx *bctx, uint32_t tlli,
			   uint8_t num_frames, uint32_t num_octets)
{
	struct msgb *msg = bssgp_msgb_alloc();
	struct bssgp_normal_hdr *bgph =
			(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
	uint16_t _bvci = osmo_htons(bctx->bvci);
	uint32_t _oct_aff = osmo_htonl(num_octets & 0xFFFFFF);

	LOGP(DBSSGP, LOGL_NOTICE, "BSSGP (BVCI=%u) Tx LLC-DISCARDED "
	     "TLLI=0x%04x, FRAMES=%u, OCTETS=%u\n", bctx->bvci, tlli,
	     num_frames, num_octets);
	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = 0; /* Signalling */
	bgph->pdu_type = BSSGP_PDUT_LLC_DISCARD;

	bssgp_msgb_tlli_put(msg, tlli);

	msgb_tvlv_put(msg, BSSGP_IE_LLC_FRAMES_DISCARDED, 1, &num_frames);
	msgb_tvlv_put(msg, BSSGP_IE_BVCI, 2, (uint8_t *) &_bvci);
	msgb_tvlv_put(msg, BSSGP_IE_NUM_OCT_AFF, 3, ((uint8_t *) &_oct_aff) + 1);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! Transmit a BVC-BLOCK message (Chapter 10.4.8) */
int bssgp_tx_bvc_block(struct bssgp_bvc_ctx *bctx, uint8_t cause)
{
	struct msgb *msg = bssgp_msgb_alloc();
	struct bssgp_normal_hdr *bgph =
			(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
	uint16_t _bvci = osmo_htons(bctx->bvci);

	LOGP(DBSSGP, LOGL_NOTICE, "BSSGP (BVCI=%u) Tx BVC-BLOCK "
		"CAUSE=%s\n", bctx->bvci, bssgp_cause_str(cause));

	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = 0; /* Signalling */
	bgph->pdu_type = BSSGP_PDUT_BVC_BLOCK;

	msgb_tvlv_put(msg, BSSGP_IE_BVCI, 2, (uint8_t *) &_bvci);
	msgb_tvlv_put(msg, BSSGP_IE_CAUSE, 1, &cause);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! Transmit a BVC-UNBLOCK message (Chapter 10.4.10) */
int bssgp_tx_bvc_unblock(struct bssgp_bvc_ctx *bctx)
{
	struct msgb *msg = bssgp_msgb_alloc();
	struct bssgp_normal_hdr *bgph =
			(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
	uint16_t _bvci = osmo_htons(bctx->bvci);

	LOGP(DBSSGP, LOGL_NOTICE, "BSSGP (BVCI=%u) Tx BVC-UNBLOCK\n", bctx->bvci);

	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = 0; /* Signalling */
	bgph->pdu_type = BSSGP_PDUT_BVC_UNBLOCK;

	msgb_tvlv_put(msg, BSSGP_IE_BVCI, 2, (uint8_t *) &_bvci);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! Transmit a BVC-RESET message (Chapter 10.4.12) */
int bssgp_tx_bvc_reset(struct bssgp_bvc_ctx *bctx, uint16_t bvci, uint8_t cause)
{
	struct msgb *msg = bssgp_msgb_alloc();
	struct bssgp_normal_hdr *bgph =
			(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
	uint16_t _bvci = osmo_htons(bvci);

	LOGP(DBSSGP, LOGL_NOTICE, "BSSGP (BVCI=%u) Tx BVC-RESET "
		"CAUSE=%s\n", bvci, bssgp_cause_str(cause));

	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = 0; /* Signalling */
	bgph->pdu_type = BSSGP_PDUT_BVC_RESET;

	msgb_tvlv_put(msg, BSSGP_IE_BVCI, 2, (uint8_t *) &_bvci);
	msgb_tvlv_put(msg, BSSGP_IE_CAUSE, 1, &cause);
	if (bvci != BVCI_PTM) {
		uint8_t bssgp_cid[8];
		bssgp_create_cell_id(bssgp_cid, &bctx->ra_id, bctx->cell_id);
		msgb_tvlv_put(msg, BSSGP_IE_CELL_ID, sizeof(bssgp_cid), bssgp_cid);
	}
	/* Optional: Feature Bitmap */

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! Transmit a FLOW_CONTROL-BVC (Chapter 10.4.4)
 *  \param[in] bctx BVC Context
 *  \param[in] tag Additional tag to identify acknowledge
 *  \param[in] bucket_size Maximum bucket size in octets
 *  \param[in] bucket_leak_rate Bucket leak rate in octets/sec
 *  \param[in] bmax_default_ms Maximum bucket size default for MS
 *  \param[in] r_default_ms Bucket leak rate default for MS in octets/sec
 *  \param[in] bucket_full_ratio Ratio (in percent) of queue filling
 *  \param[in] queue_delay_ms Average queuing delay in milliseconds
 */
int bssgp_tx_fc_bvc(struct bssgp_bvc_ctx *bctx, uint8_t tag,
		    uint32_t bucket_size, uint32_t bucket_leak_rate,
		    uint32_t bmax_default_ms, uint32_t r_default_ms,
		    uint8_t *bucket_full_ratio, uint32_t *queue_delay_ms)
{
	struct msgb *msg;
	struct bssgp_normal_hdr *bgph;
	uint16_t e_bucket_size, e_leak_rate, e_bmax_default_ms, e_r_default_ms;
	uint16_t e_queue_delay = 0; /* to make gcc happy */

	if ((bucket_size / 100) > 0xffff)
		return -EINVAL;
	e_bucket_size = osmo_htons(bucket_size / 100);

	if ((bucket_leak_rate * 8 / 100) > 0xffff)
		return -EINVAL;
	e_leak_rate = osmo_htons((bucket_leak_rate * 8) / 100);

	if ((bmax_default_ms / 100) > 0xffff)
		return -EINVAL;
	e_bmax_default_ms = osmo_htons(bmax_default_ms / 100);

	if ((r_default_ms * 8 / 100) > 0xffff)
		return -EINVAL;
	e_r_default_ms = osmo_htons((r_default_ms * 8) / 100);

	if (queue_delay_ms) {
		if ((*queue_delay_ms / 10) > 60000)
			return -EINVAL;
		else if (*queue_delay_ms == 0xFFFFFFFF)
			e_queue_delay = 0xFFFF;
		else
			e_queue_delay = osmo_htons(*queue_delay_ms / 10);
	}

	msg = bssgp_msgb_alloc();
	bgph = (struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = bctx->bvci;
	bgph->pdu_type = BSSGP_PDUT_FLOW_CONTROL_BVC;

	msgb_tvlv_put(msg, BSSGP_IE_TAG, sizeof(tag), (uint8_t *)&tag);
	msgb_tvlv_put(msg, BSSGP_IE_BVC_BUCKET_SIZE,
		     sizeof(e_bucket_size), (uint8_t *) &e_bucket_size);
	msgb_tvlv_put(msg, BSSGP_IE_BUCKET_LEAK_RATE,
		      sizeof(e_leak_rate), (uint8_t *) &e_leak_rate);
	msgb_tvlv_put(msg, BSSGP_IE_BMAX_DEFAULT_MS,
		      sizeof(e_bmax_default_ms),
					(uint8_t *) &e_bmax_default_ms);
	msgb_tvlv_put(msg, BSSGP_IE_R_DEFAULT_MS,
		      sizeof(e_r_default_ms), (uint8_t *) &e_r_default_ms);
	if (bucket_full_ratio)
		msgb_tvlv_put(msg, BSSGP_IE_BUCKET_FULL_RATIO,
			      1, bucket_full_ratio);
	if (queue_delay_ms)
		msgb_tvlv_put(msg, BSSGP_IE_BVC_MEASUREMENT,
			      sizeof(e_queue_delay),
			      (uint8_t *) &e_queue_delay);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! Transmit a FLOW_CONTROL-MS (Chapter 10.4.6)
 *  \param[in] bctx BVC Context
 *  \param[in] tlli TLLI to identify MS
 *  \param[in] tag Additional tag to identify acknowledge
 *  \param[in] ms_bucket_size Maximum bucket size in octets
 *  \param[in] bucket_leak_rate Bucket leak rate in octets/sec
 *  \param[in] bucket_full_ratio Ratio (in percent) of queue filling
 */
int bssgp_tx_fc_ms(struct bssgp_bvc_ctx *bctx, uint32_t tlli, uint8_t tag,
		   uint32_t ms_bucket_size, uint32_t bucket_leak_rate,
		   uint8_t *bucket_full_ratio)
{
	struct msgb *msg;
	struct bssgp_normal_hdr *bgph;
	uint16_t e_bucket_size, e_leak_rate;

	if ((ms_bucket_size / 100) > 0xffff)
		return -EINVAL;
	e_bucket_size = ms_bucket_size / 100;

	if ((bucket_leak_rate * 8 / 100) > 0xffff)
		return -EINVAL;
	e_leak_rate = (bucket_leak_rate * 8) / 100;

	msg = bssgp_msgb_alloc();
	bgph = (struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = bctx->bvci;
	bgph->pdu_type = BSSGP_PDUT_FLOW_CONTROL_MS;

	bssgp_msgb_tlli_put(msg, tlli);
	msgb_tvlv_put(msg, BSSGP_IE_TAG, sizeof(tag), (uint8_t *)&tag);
	msgb_tvlv_put(msg, BSSGP_IE_MS_BUCKET_SIZE,
		      sizeof(e_bucket_size), (uint8_t *) &e_bucket_size);
	msgb_tvlv_put(msg, BSSGP_IE_BUCKET_LEAK_RATE,
		      sizeof(e_leak_rate), (uint8_t *) &e_leak_rate);
	if (bucket_full_ratio)
		msgb_tvlv_put(msg, BSSGP_IE_BUCKET_FULL_RATIO,
			      1, bucket_full_ratio);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/*! RL-UL-UNITDATA.req (Chapter 10.2.2)
 *  \param[in] bctx BVC Context
 *  \param[in] tlli TLLI to identify MS
 *  \param[in] qos_profile Pointer to three octests of QoS profile
 *  \param[in] llc_pdu msgb pointer containing UL Unitdata IE payload
 */
int bssgp_tx_ul_ud(struct bssgp_bvc_ctx *bctx, uint32_t tlli,
		   const uint8_t *qos_profile, struct msgb *llc_pdu)
{
	struct msgb *msg = llc_pdu;
	uint8_t bssgp_cid[8];
	uint8_t bssgp_align[3] = {0, 0, 0};
	struct bssgp_ud_hdr *budh;
	int align = sizeof(*budh);

	/* FIXME: Optional LSA Identifier List, PFI */

	/* Cell Identifier */
	bssgp_create_cell_id(bssgp_cid, &bctx->ra_id, bctx->cell_id);
	align += 2; /* add T+L */
	align += sizeof(bssgp_cid);

	/* First push alignment IE */
	align += 2; /* add T+L */
	align = (4 - align) & 3; /* how many octest are required to align? */
	msgb_tvlv_push(msg, BSSGP_IE_ALIGNMENT, align, bssgp_align);

	/* Push other IEs */
	msgb_tvlv_push(msg, BSSGP_IE_CELL_ID, sizeof(bssgp_cid), bssgp_cid);

	/* User Data Header */
	budh = (struct bssgp_ud_hdr *) msgb_push(msg, sizeof(*budh));
	budh->tlli = osmo_htonl(tlli);
	memcpy(budh->qos_profile, qos_profile, 3);
	budh->pdu_type = BSSGP_PDUT_UL_UNITDATA;

	/* set NSEI and BVCI in msgb cb */
	msgb_nsei(msg) = bctx->nsei;
	msgb_bvci(msg) = bctx->bvci;

	rate_ctr_inc(&bctx->ctrg->ctr[BSSGP_CTR_PKTS_OUT]);
	rate_ctr_add(&bctx->ctrg->ctr[BSSGP_CTR_BYTES_OUT], msg->len);

	return gprs_ns_sendmsg(bssgp_nsi, msg);
}

/* Parse a single GMM-PAGING.req to a given NSEI/NS-BVCI */
int bssgp_rx_paging(struct bssgp_paging_info *pinfo,
		    struct msgb *msg)
{
	struct bssgp_normal_hdr *bgph =
			(struct bssgp_normal_hdr *) msgb_bssgph(msg);
	struct tlv_parsed tp;
	uint8_t ra[6];
	int rc, data_len;

	memset(ra, 0, sizeof(ra));

	data_len = msgb_bssgp_len(msg) - sizeof(*bgph);
	rc = bssgp_tlv_parse(&tp, bgph->data, data_len);
	if (rc < 0)
		goto err_mand_ie;

	switch (bgph->pdu_type) {
	case BSSGP_PDUT_PAGING_PS:
		pinfo->mode = BSSGP_PAGING_PS;
		break;
	case BSSGP_PDUT_PAGING_CS:
		pinfo->mode = BSSGP_PAGING_CS;
		break;
	default:
		return -EINVAL;
	}

	/* IMSI */
	if (!TLVP_PRESENT(&tp, BSSGP_IE_IMSI))
		goto err_mand_ie;
	if (!pinfo->imsi)
		pinfo->imsi = talloc_zero_size(pinfo, GSM_IMSI_LENGTH);
	gsm48_mi_to_string(pinfo->imsi, GSM_IMSI_LENGTH,
			   TLVP_VAL(&tp, BSSGP_IE_IMSI),
			   TLVP_LEN(&tp, BSSGP_IE_IMSI));

	/* DRX Parameters */
	if (!TLVP_PRESENT(&tp, BSSGP_IE_DRX_PARAMS))
		goto err_mand_ie;
	pinfo->drx_params = tlvp_val16be(&tp, BSSGP_IE_DRX_PARAMS);

	/* Scope */
	if (TLVP_PRESENT(&tp, BSSGP_IE_BSS_AREA_ID)) {
		pinfo->scope = BSSGP_PAGING_BSS_AREA;
	} else if (TLVP_PRESENT(&tp, BSSGP_IE_LOCATION_AREA)) {
		pinfo->scope = BSSGP_PAGING_LOCATION_AREA;
		memcpy(ra, TLVP_VAL(&tp, BSSGP_IE_LOCATION_AREA),
			TLVP_LEN(&tp, BSSGP_IE_LOCATION_AREA));
		gsm48_parse_ra(&pinfo->raid, ra);
	} else if (TLVP_PRESENT(&tp, BSSGP_IE_ROUTEING_AREA)) {
		pinfo->scope = BSSGP_PAGING_ROUTEING_AREA;
		memcpy(ra, TLVP_VAL(&tp, BSSGP_IE_ROUTEING_AREA),
			TLVP_LEN(&tp, BSSGP_IE_ROUTEING_AREA));
		gsm48_parse_ra(&pinfo->raid, ra);
	} else if (TLVP_PRESENT(&tp, BSSGP_IE_BVCI)) {
		pinfo->scope = BSSGP_PAGING_BVCI;
		pinfo->bvci = tlvp_val16be(&tp, BSSGP_IE_BVCI);
	} else
		return -EINVAL;

	/* QoS profile mandatory for PS */
	if (pinfo->mode == BSSGP_PAGING_PS) {
		if (!TLVP_PRESENT(&tp, BSSGP_IE_QOS_PROFILE))
			goto err_cond_ie;
		if (TLVP_LEN(&tp, BSSGP_IE_QOS_PROFILE) < 3)
			goto err;

		memcpy(&pinfo->qos, TLVP_VAL(&tp, BSSGP_IE_QOS_PROFILE),
			3);
	}

	/* Optional (P-)TMSI */
	if (TLVP_PRESENT(&tp, BSSGP_IE_TMSI) &&
	    TLVP_LEN(&tp, BSSGP_IE_TMSI) >= 4) {
		if (!pinfo->ptmsi)
			pinfo->ptmsi = talloc_zero_size(pinfo, sizeof(uint32_t));
		*(pinfo->ptmsi) = osmo_load32be(TLVP_VAL(&tp, BSSGP_IE_TMSI));
	}

	return 0;

err_mand_ie:
err_cond_ie:
err:
	/* FIXME */
	return 0;
}