aboutsummaryrefslogtreecommitdiffstats
path: root/src/osmo-bts-sysmo/tch.c
blob: 322e45743eb48224c783b0dcc9bc69d58999f4dc (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
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
/* Traffic channel support for Sysmocom BTS L1 */

/* (C) 2011-2012 by Harald Welte <laforge@gnumonks.org>
 *
 * 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 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 <stdint.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <osmocom/core/talloc.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/select.h>
#include <osmocom/core/timer.h>
#include <osmocom/core/bits.h>
#include <osmocom/codec/codec.h>
#include <osmocom/gsm/gsm_utils.h>
#include <osmocom/trau/osmo_ortp.h>

#include <osmo-bts/logging.h>
#include <osmo-bts/bts.h>
#include <osmo-bts/gsm_data.h>
#include <osmo-bts/measurement.h>
#include <osmo-bts/amr.h>
#include <osmo-bts/l1sap.h>

#include <sysmocom/femtobts/superfemto.h>
#include <sysmocom/femtobts/gsml1prim.h>
#include <sysmocom/femtobts/gsml1const.h>
#include <sysmocom/femtobts/gsml1types.h>

#include "femtobts.h"
#include "l1_if.h"

extern void save_last_sid(struct gsm_lchan *lchan, uint8_t *l1_payload,
			  size_t length, uint32_t fn, bool update);
extern int add_l1sap_header(struct gsm_lchan *lchan, struct msgb *rmsg,
			    struct gsm_bts_trx *trx, uint8_t chan_nr,
			    uint32_t fn);

/* input octet-aligned, output not octet-aligned */
void osmo_nibble_shift_right(uint8_t *out, const uint8_t *in,
			     unsigned int num_nibbles)
{
	unsigned int i;
	unsigned int num_whole_bytes = num_nibbles / 2;

	/* first byte: upper nibble empty, lower nibble from src */
	out[0] = (in[0] >> 4);

	/* bytes 1.. */
	for (i = 1; i < num_whole_bytes; i++)
		out[i] = ((in[i-1] & 0xF) << 4) | (in[i] >> 4);

	/* shift the last nibble, in case there's an odd count */
	i = num_whole_bytes;
	if (num_nibbles & 1)
		out[i] = ((in[i-1] & 0xF) << 4) | (in[i] >> 4);
	else
		out[i] = (in[i-1] & 0xF) << 4;
}


/* input unaligned, output octet-aligned */
void osmo_nibble_shift_left_unal(uint8_t *out, const uint8_t *in,
				unsigned int num_nibbles)
{
	unsigned int i;
	unsigned int num_whole_bytes = num_nibbles / 2;

	for (i = 0; i < num_whole_bytes; i++)
		out[i] = ((in[i] & 0xF) << 4) | (in[i+1] >> 4);

	/* shift the last nibble, in case there's an odd count */
	i = num_whole_bytes;
	if (num_nibbles & 1)
		out[i] = (in[i] & 0xF) << 4;
}

void set_payload_size(struct msgb *msg, uint8_t size)
{
	GsmL1_Prim_t *l1p;
	GsmL1_PhDataReq_t *data_req;
	GsmL1_MsgUnitParam_t *msu_param;

	l1p = msgb_l1prim(msg);
	data_req = &l1p->u.phDataReq;
	msu_param = &data_req->msgUnitParam;
	msu_param->u8Size = size;
}

void set_payload_type(struct msgb *msg, struct gsm_lchan *lchan)
{
	GsmL1_Prim_t *l1p;
	GsmL1_PhDataReq_t *data_req;
	GsmL1_MsgUnitParam_t *msu_param;
	uint8_t *payload_type;

	l1p = msgb_l1prim(msg);
	data_req = &l1p->u.phDataReq;
	msu_param = &data_req->msgUnitParam;
	payload_type = &msu_param->u8Buffer[0];

	switch (lchan->tch_mode) {
	case GSM48_CMODE_SPEECH_AMR:
		*payload_type = GsmL1_TchPlType_Amr;
		break;
	case GSM48_CMODE_SPEECH_V1:
		if (lchan->type == GSM_LCHAN_TCH_F)
			*payload_type = GsmL1_TchPlType_Fr;
		else
			*payload_type = GsmL1_TchPlType_Hr;
		break;
	case GSM48_CMODE_SPEECH_EFR:
		*payload_type = GsmL1_TchPlType_Efr;
		break;
	default:
		*payload_type = GsmL1_TchPlType_NA;
	}
}

uint8_t *get_payload_addr(struct msgb *msg)
{
	GsmL1_Prim_t *l1p;
	GsmL1_PhDataReq_t *data_req;
	GsmL1_MsgUnitParam_t *msu_param;

	l1p = msgb_l1prim(msg);
	data_req = &l1p->u.phDataReq;
	msu_param = &data_req->msgUnitParam;

	return &msu_param->u8Buffer[1];
}

static struct msgb *l1_to_rtppayload_fr(uint8_t *l1_payload, uint8_t payload_len,
					struct gsm_lchan *lchan)
{
	struct msgb *msg;
	uint8_t *cur;

	msg = msgb_alloc_headroom(1024, 128, "L1C-to-RTP");
	if (!msg)
		return NULL;

#ifdef USE_L1_RTP_MODE
	/* new L1 can deliver bits like we need them */
	cur = msgb_put(msg, GSM_FR_BYTES);
	memcpy(cur, l1_payload, GSM_FR_BYTES);
#else
	/* step1: reverse the bit-order of each payload byte */
	osmo_revbytebits_buf(l1_payload, payload_len);

	cur = msgb_put(msg, GSM_FR_BYTES);

	/* step2: we need to shift the entire L1 payload by 4 bits right */
	osmo_nibble_shift_right(cur, l1_payload, GSM_FR_BITS/4);

	cur[0] |= 0xD0;
#endif /* USE_L1_RTP_MODE */

	if (osmo_fr_check_sid(l1_payload, payload_len))
		lchan->tch.ul_sid = true;
	else if (lchan->tch.ul_sid) {
		lchan->tch.ul_sid = false;
		lchan->rtp_tx_marker = true;
	}

	return msg;
}

/*! \brief convert GSM-FR from RTP payload to L1 format
 *  \param[out] l1_payload payload part of L1 buffer
 *  \param[in] rtp_payload pointer to RTP payload data
 *  \param[in] payload_len length of \a rtp_payload
 *  \returns number of \a l1_payload bytes filled
 */
static int rtppayload_to_l1_fr(uint8_t *l1_payload, uint8_t *rtp_payload,
			       unsigned int payload_len, struct gsm_lchan *lchan,
			       uint32_t fn)
{
#ifdef USE_L1_RTP_MODE
	/* new L1 can deliver bits like we need them */
	memcpy(l1_payload, rtp_payload, GSM_FR_BYTES);
#else
	/* step2: we need to shift the RTP payload left by one nibble*/
	osmo_nibble_shift_left_unal(l1_payload, rtp_payload, GSM_FR_BITS/4);

	/* step1: reverse the bit-order of each payload byte */
	osmo_revbytebits_buf(l1_payload, payload_len);
#endif /* USE_L1_RTP_MODE */

	if (osmo_fr_check_sid(l1_payload, payload_len))
		save_last_sid(lchan, l1_payload, payload_len, fn, false);

	return GSM_FR_BYTES;
}

#if defined(L1_HAS_EFR) && defined(USE_L1_RTP_MODE)
static struct msgb *l1_to_rtppayload_efr(uint8_t *l1_payload,
					 uint8_t payload_len,
					 struct gsm_lchan *lchan)
{
	struct msgb *msg;
	uint8_t *cur;

	msg = msgb_alloc_headroom(1024, 128, "L1C-to-RTP");
	if (!msg)
		return NULL;

#ifdef USE_L1_RTP_MODE
	/* new L1 can deliver bits like we need them */
	cur = msgb_put(msg, GSM_EFR_BYTES);
	memcpy(cur, l1_payload, GSM_EFR_BYTES);
#else
	/* step1: reverse the bit-order of each payload byte */
	osmo_revbytebits_buf(l1_payload, payload_len);

	cur = msgb_put(msg, GSM_EFR_BYTES);

	/* step 2: we need to shift the entire L1 payload by 4 bits right */
	osmo_nibble_shift_right(cur, l1_payload, GSM_EFR_BITS/4);

	cur[0] |= 0xC0;
#endif /* USE_L1_RTP_MODE */
	enum osmo_amr_type ft;
	enum osmo_amr_quality bfi;
	uint8_t cmr;
	int8_t sti, cmi;
	osmo_amr_rtp_dec(l1_payload, payload_len, &cmr, &cmi, &ft, &bfi, &sti);
	if (ft == AMR_GSM_EFR_SID)
		lchan->tch.ul_sid = true;
	else if (lchan->tch.ul_sid) {
		lchan->tch.ul_sid = false;
		lchan->rtp_tx_marker = true;
	}
	return msg;
}

static int rtppayload_to_l1_efr(uint8_t *l1_payload, const uint8_t *rtp_payload,
				unsigned int payload_len,
				struct gsm_lchan *lchan, uint32_t fn)
{
#ifndef USE_L1_RTP_MODE
#error We don't support EFR with L1 that doesn't support RTP mode!
#else
	memcpy(l1_payload, rtp_payload, payload_len);
	enum osmo_amr_type ft;
	enum osmo_amr_quality bfi;
	uint8_t cmr;
	int8_t sti, cmi;
	osmo_amr_rtp_dec(rtp_payload, payload_len, &cmr, &cmi, &ft, &bfi, &sti);
	if (ft == AMR_GSM_EFR_SID)
		save_last_sid(lchan, l1_payload, payload_len, fn, false);
	return payload_len;
#endif
}
#else
#warning No EFR support in L1
#endif /* L1_HAS_EFR */

static struct msgb *l1_to_rtppayload_hr(uint8_t *l1_payload, uint8_t payload_len,
					struct gsm_lchan *lchan)
{
	struct msgb *msg;
	uint8_t *cur;

	msg = msgb_alloc_headroom(1024, 128, "L1C-to-RTP");
	if (!msg)
		return NULL;

	if (payload_len != GSM_HR_BYTES) {
		LOGP(DL1C, LOGL_ERROR, "L1 HR frame length %u != expected %u\n",
			payload_len, GSM_HR_BYTES);
		return NULL;
	}

	cur = msgb_put(msg, GSM_HR_BYTES);
	memcpy(cur, l1_payload, GSM_HR_BYTES);

#ifndef USE_L1_RTP_MODE
	/* reverse the bit-order of each payload byte */
	osmo_revbytebits_buf(cur, GSM_HR_BYTES);
#endif /* USE_L1_RTP_MODE */

	if (osmo_hr_check_sid(l1_payload, payload_len))
		lchan->tch.ul_sid = true;
	else if (lchan->tch.ul_sid) {
		lchan->tch.ul_sid = false;
		lchan->rtp_tx_marker = true;
	}

	return msg;
}

/*! \brief convert GSM-FR from RTP payload to L1 format
 *  \param[out] l1_payload payload part of L1 buffer
 *  \param[in] rtp_payload pointer to RTP payload data
 *  \param[in] payload_len length of \a rtp_payload
 *  \returns number of \a l1_payload bytes filled
 */
static int rtppayload_to_l1_hr(uint8_t *l1_payload, uint8_t *rtp_payload,
			       unsigned int payload_len, struct gsm_lchan *lchan,
			       uint32_t fn)
{

	if (payload_len != GSM_HR_BYTES) {
		LOGP(DL1C, LOGL_ERROR, "RTP HR frame length %u != expected %u\n",
			payload_len, GSM_HR_BYTES);
		return 0;
	}

	memcpy(l1_payload, rtp_payload, GSM_HR_BYTES);

#ifndef USE_L1_RTP_MODE
	/* reverse the bit-order of each payload byte */
	osmo_revbytebits_buf(l1_payload, GSM_HR_BYTES);
#endif /* USE_L1_RTP_MODE */

	if (osmo_hr_check_sid(l1_payload, payload_len))
		save_last_sid(lchan, l1_payload, payload_len, fn, false);

	return GSM_HR_BYTES;
}

static struct msgb *l1_to_rtppayload_amr(uint8_t *l1_payload, uint8_t payload_len,
					 struct gsm_lchan *lchan)
{
#ifndef USE_L1_RTP_MODE
	struct amr_multirate_conf *amr_mrc = &lchan->tch.amr_mr;
#endif
	struct msgb *msg;
	uint8_t amr_if2_len = payload_len - 2;
	uint8_t *cur;

	msg = msgb_alloc_headroom(1024, 128, "L1C-to-RTP");
	if (!msg)
		return NULL;

#ifdef USE_L1_RTP_MODE
	cur = msgb_put(msg, amr_if2_len);
	memcpy(cur, l1_payload+2, amr_if2_len);

	/*
	 * Audiocode's MGW doesn't like receiving CMRs that are not
	 * the same as the previous one. This means we need to patch
	 * the content here.
	 */
	if ((cur[0] & 0xF0) == 0xF0)
		cur[0]= lchan->tch.last_cmr << 4;
	else
		lchan->tch.last_cmr = cur[0] >> 4;
#else
	u_int8_t cmr;
	uint8_t ft = l1_payload[2] & 0xF;
	uint8_t cmr_idx = l1_payload[1];
	/* CMR == Unset means CMR was not transmitted at this TDMA */
	if (cmr_idx == GsmL1_AmrCodecMode_Unset)
		cmr = lchan->tch.last_cmr;
	else if (cmr_idx >= amr_mrc->num_modes ||
		 cmr_idx > GsmL1_AmrCodecMode_Unset) {
		/* Make sure the CMR of the phone is in the active codec set */
		LOGP(DL1C, LOGL_NOTICE, "L1->RTP: overriding CMR IDX %u\n", cmr_idx);
		cmr = AMR_CMR_NONE;
	} else {
		cmr = amr_mrc->bts_mode[cmr_idx].mode;
		lchan->tch.last_cmr = cmr;
	}

	/* RFC 3267  4.4.1 Payload Header */
	msgb_put_u8(msg, (cmr << 4));

	/* RFC 3267  AMR TOC */
	msgb_put_u8(msg, AMR_TOC_QBIT | (ft << 3));

	cur = msgb_put(msg, amr_if2_len-1);

	/* step1: reverse the bit-order within every byte */
	osmo_revbytebits_buf(l1_payload+2, amr_if2_len);

	/* step2: shift everything left by one nibble */
	osmo_nibble_shift_left_unal(cur, l1_payload+2, amr_if2_len*2 -1);

#endif /* USE_L1_RTP_MODE */

	return msg;
}

int get_amr_mode_idx(const struct amr_multirate_conf *amr_mrc, uint8_t cmi)
{
	unsigned int i;
	for (i = 0; i < amr_mrc->num_modes; i++) {
		if (amr_mrc->bts_mode[i].mode == cmi)
			return i;
	}
	return -EINVAL;
}

/*! \brief convert AMR from RTP payload to L1 format
 *  \param[out] l1_payload payload part of L1 buffer
 *  \param[in] rtp_payload pointer to RTP payload data
 *  \param[in] payload_len length of \a rtp_payload
 *  \returns number of \a l1_payload bytes filled
 */
static int rtppayload_to_l1_amr(uint8_t *l1_payload, const uint8_t *rtp_payload,
				uint8_t payload_len,
				struct gsm_lchan *lchan, uint32_t fn)
{
	struct amr_multirate_conf *amr_mrc = &lchan->tch.amr_mr;
	enum osmo_amr_type ft;
	enum osmo_amr_quality bfi;
	uint8_t cmr;
	int8_t sti, cmi;
	uint8_t *l1_cmi_idx = l1_payload;
	uint8_t *l1_cmr_idx = l1_payload+1;
	int rc;

	osmo_amr_rtp_dec(rtp_payload, payload_len, &cmr, &cmi, &ft, &bfi, &sti);

#ifdef USE_L1_RTP_MODE
	memcpy(l1_payload+2, rtp_payload, payload_len);
#else
	uint8_t amr_if2_core_len = payload_len - 2;

	/* step1: shift everything right one nibble; make space for FT */
	osmo_nibble_shift_right(l1_payload+2, rtp_payload+2, amr_if2_core_len*2);
	/* step2: reverse the bit-order within every byte of the IF2
	 * core frame contained in the RTP payload */
	osmo_revbytebits_buf(l1_payload+2, amr_if2_core_len+1);

	/* lower 4 bit of first FR2 byte contains FT */
	l1_payload[2] |= ft;
#endif /* USE_L1_RTP_MODE */

	/* CMI in downlink tells the L1 encoder which encoding function
	 * it will use, so we have to use the frame type */
	switch (ft) {
	case 0: case 1: case 2: case 3:
	case 4: case 5: case 6: case 7:
		cmi = ft;
		LOGP(DRTP, LOGL_DEBUG, "SPEECH frame with CMI %u\n", cmi);
		break;
	case AMR_SID:
		LOGP(DRTP, LOGL_DEBUG, "SID %s frame with CMI %u\n",
		     sti ? "UPDATE" : "FIRST", cmi);
		break;
	default:
		LOGP(DRTP, LOGL_ERROR, "unsupported AMR FT 0x%02x\n", ft);
		return -EINVAL;
		break;
	}

	rc = get_amr_mode_idx(amr_mrc, cmi);
	if (rc < 0) {
		LOGP(DRTP, LOGL_ERROR, "AMR CMI %u not part of AMR MR set\n",
			cmi);
		*l1_cmi_idx = 0;
	} else
		*l1_cmi_idx = rc;

	/* Codec Mode Request is in upper 4 bits of RTP payload header,
	 * and we simply copy the CMR into the CMC */
	if (cmr == 0xF) {
		/* FIXME: we need some state about the last codec mode */
		*l1_cmr_idx = 0;
	} else {
		rc = get_amr_mode_idx(amr_mrc, cmr);
		if (rc < 0) {
			/* FIXME: we need some state about the last codec mode */
			LOGP(DRTP, LOGL_INFO, "RTP->L1: overriding CMR %u\n", cmr);
			*l1_cmr_idx = 0;
		} else
			*l1_cmr_idx = rc;
	}
#if 0
	/* check for bad quality indication */
	if (bfi == AMR_GOOD) {
		/* obtain frame type from AMR FT */
		l1_payload[2] = ft;
	} else {
		/* bad quality, we should indicate that... */
		if (ft == AMR_SID) {
			/* FIXME: Should we do GsmL1_TchPlType_Amr_SidBad? */
			l1_payload[2] = ft;
		} else {
			l1_payload[2] = ft;
		}
	}
#endif

	if (ft == AMR_SID)
		save_last_sid(lchan, l1_payload, payload_len, fn,
			      sti ? true : false);

	return payload_len+1;
}

#define RTP_MSGB_ALLOC_SIZE	512

/*! \brief function for incoming RTP via TCH.req
 *  \param rs RTP Socket
 *  \param[in] rtp_pl buffer containing RTP payload
 *  \param[in] rtp_pl_len length of \a rtp_pl
 *
 * This function prepares a msgb with a L1 PH-DATA.req primitive and
 * queues it into lchan->dl_tch_queue.
 *
 * Note that the actual L1 primitive header is not fully initialized
 * yet, as things like the frame number, etc. are unknown at the time we
 * pre-fill the primtive.
 */
void l1if_tch_encode(struct gsm_lchan *lchan, uint8_t *data, uint8_t *len,
		     uint8_t *rtp_pl, unsigned int rtp_pl_len, uint32_t fn)
{
	uint8_t *payload_type;
	uint8_t *l1_payload;
	int rc;

	DEBUGP(DRTP, "%s RTP IN: %s\n", gsm_lchan_name(lchan),
		osmo_hexdump(rtp_pl, rtp_pl_len));

	payload_type = &data[0];
	l1_payload = &data[1];

	switch (lchan->tch_mode) {
	case GSM48_CMODE_SPEECH_V1:
		if (lchan->type == GSM_LCHAN_TCH_F) {
			*payload_type = GsmL1_TchPlType_Fr;
			rc = rtppayload_to_l1_fr(l1_payload,
						 rtp_pl, rtp_pl_len, lchan, fn);
		} else{
			*payload_type = GsmL1_TchPlType_Hr;
			rc = rtppayload_to_l1_hr(l1_payload,
						 rtp_pl, rtp_pl_len, lchan, fn);
		}
		break;
#if defined(L1_HAS_EFR) && defined(USE_L1_RTP_MODE)
	case GSM48_CMODE_SPEECH_EFR:
		*payload_type = GsmL1_TchPlType_Efr;
		rc = rtppayload_to_l1_efr(l1_payload, rtp_pl,
					  rtp_pl_len, lchan, fn);
		break;
#endif
	case GSM48_CMODE_SPEECH_AMR:
		*payload_type = GsmL1_TchPlType_Amr;
		rc = rtppayload_to_l1_amr(l1_payload, rtp_pl,
					  rtp_pl_len, lchan, fn);
		break;
	default:
		/* we don't support CSD modes */
		rc = -1;
		break;
	}

	if (rc < 0) {
		LOGP(DRTP, LOGL_ERROR, "%s unable to parse RTP payload\n",
		     gsm_lchan_name(lchan));
		return;
	}

	*len = rc + 1;

	DEBUGP(DRTP, "%s RTP->L1: %s\n", gsm_lchan_name(lchan),
		osmo_hexdump(data, *len));
}

static int is_recv_only(uint8_t speech_mode)
{
	return (speech_mode & 0xF0) == (1 << 4);
}

/*! \brief receive a traffic L1 primitive for a given lchan */
int l1if_tch_rx(struct gsm_bts_trx *trx, uint8_t chan_nr, struct msgb *l1p_msg)
{
	GsmL1_Prim_t *l1p = msgb_l1prim(l1p_msg);
	GsmL1_PhDataInd_t *data_ind = &l1p->u.phDataInd;
	uint8_t payload_type = data_ind->msgUnitParam.u8Buffer[0];
	uint8_t *payload = data_ind->msgUnitParam.u8Buffer + 1;
	uint8_t payload_len;
	struct msgb *rmsg = NULL;
	struct gsm_lchan *lchan = &trx->ts[L1SAP_CHAN2TS(chan_nr)].lchan[l1sap_chan2ss(chan_nr)];

	if (is_recv_only(lchan->abis_ip.speech_mode))
		return -EAGAIN;

	if (data_ind->msgUnitParam.u8Size < 1) {
		LOGP(DL1C, LOGL_ERROR, "chan_nr %d Rx Payload size 0\n",
			chan_nr);
		return -EINVAL;
	}
	payload_len = data_ind->msgUnitParam.u8Size - 1;

	switch (payload_type) {
	case GsmL1_TchPlType_Fr:
#if defined(L1_HAS_EFR) && defined(USE_L1_RTP_MODE)
	case GsmL1_TchPlType_Efr:
#endif
		if (lchan->type != GSM_LCHAN_TCH_F)
			goto err_payload_match;
		break;
	case GsmL1_TchPlType_Hr:
		if (lchan->type != GSM_LCHAN_TCH_H)
			goto err_payload_match;
		break;
	case GsmL1_TchPlType_Amr:
		if (lchan->type != GSM_LCHAN_TCH_H &&
		    lchan->type != GSM_LCHAN_TCH_F)
			goto err_payload_match;
		break;
	case GsmL1_TchPlType_Amr_Onset:
		if (lchan->type != GSM_LCHAN_TCH_H &&
		    lchan->type != GSM_LCHAN_TCH_F)
			goto err_payload_match;
		/* according to 3GPP TS 26.093 ONSET frames precede the first
		   speech frame of a speech burst - set the marker for next RTP
		   frame and drop last SID */
		lchan->rtp_tx_marker = true;
		break;
	default:
		LOGP(DL1C, LOGL_NOTICE, "%s Rx Payload Type %s is unsupported\n",
			gsm_lchan_name(lchan),
			get_value_string(femtobts_tch_pl_names, payload_type));
		break;
	}


	switch (payload_type) {
	case GsmL1_TchPlType_Fr:
		rmsg = l1_to_rtppayload_fr(payload, payload_len, lchan);
		break;
	case GsmL1_TchPlType_Hr:
		rmsg = l1_to_rtppayload_hr(payload, payload_len, lchan);
		break;
#if defined(L1_HAS_EFR) && defined(USE_L1_RTP_MODE)
	case GsmL1_TchPlType_Efr:
		rmsg = l1_to_rtppayload_efr(payload, payload_len, lchan);
		break;
#endif
	case GsmL1_TchPlType_Amr:
		rmsg = l1_to_rtppayload_amr(payload, payload_len, lchan);
		break;
	}

	if (rmsg)
		return add_l1sap_header(lchan, rmsg, trx, chan_nr,
					data_ind->u32Fn);

	return 0;

err_payload_match:
	LOGP(DL1C, LOGL_ERROR, "%s Rx Payload Type %s incompatible with lchan\n",
		gsm_lchan_name(lchan),
		get_value_string(femtobts_tch_pl_names, payload_type));
	return -EINVAL;
}