Change in libosmo-abis[master]: trau_frame: New API

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laforge gerrit-no-reply at lists.osmocom.org
Mon Aug 3 01:11:35 UTC 2020


laforge has submitted this change. ( https://gerrit.osmocom.org/c/libosmo-abis/+/18249 )

Change subject: trau_frame: New API
......................................................................

trau_frame: New API

The old TRAU frame code in src/trau_frame.c (which is for some strange
reason part of libosmo-abis, and not libosmo-trau!) was introduced more
than a decade ago for the needs of bs11_abis AKA OpenBSC aka OsmoNITB.

It is too constrained to implement TRAU frame parsing in a generic way,
including:
* no way to add support for 8k sub-slots
* no way to handle CRC bits or UFI (i.e. no AMR)
* no real API design, it was just ripped out from OsmoNITB and moved into
  a library (even the wrong one)

For those reasons, let's introduce a new API for TRAU frame
encoding/decoding - one that supports all the relevant use cases.

Change-Id: I5cf42e6c445d9224be18503cebc7584b3beba08c
---
M include/Makefile.am
A include/osmocom/trau/trau_frame.h
M src/Makefile.am
A src/trau/trau_frame.c
4 files changed, 1,514 insertions(+), 2 deletions(-)

Approvals:
  laforge: Looks good to me, approved
  Jenkins Builder: Verified



diff --git a/include/Makefile.am b/include/Makefile.am
index 2048520..aa735c5 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -4,4 +4,5 @@
  osmocom/abis/ipa_proxy.h osmocom/abis/ipaccess.h osmocom/abis/abis.h	\
  osmocom/abis/subchan_demux.h osmocom/abis/e1_input.h			\
  osmocom/abis/lapd.h osmocom/abis/lapd_pcap.h osmocom/trau/osmo_ortp.h	\
- osmocom/abis/unixsocket_proto.h
+ osmocom/abis/unixsocket_proto.h \
+ osmocom/trau/trau_frame.h
diff --git a/include/osmocom/trau/trau_frame.h b/include/osmocom/trau/trau_frame.h
new file mode 100644
index 0000000..6784d1f
--- /dev/null
+++ b/include/osmocom/trau/trau_frame.h
@@ -0,0 +1,146 @@
+#pragma once
+/* TRAU frame handling according to GSM TS 48.060 / 48.061 */
+
+/* (C) 2020 by Harald Welte <laforge at gnumonks.org>
+ * All Rights Reserved
+ *
+ * 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 Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <osmocom/core/bits.h>
+#include <osmocom/core/utils.h>
+
+/*! \defgroup trau_frame TRAU frame handling
+ *  @{
+ *
+ *  \file trau_frame.h
+ */
+
+/*! \brief Maximum number of C-bits in a TRAU frame:
+ * 21 for FR/EFR, 25 for AMR, 15 for OM, 15 for data, 13 for E-data, 21 idle */
+#define MAX_C_BITS	25
+/*! \brief Maximum number of D-bits in a TRAU frame:
+ * 260 for FR/EFR, 256 for AMR, 264 for OM, 288 for E-data */
+#define MAX_D_BITS	288
+/*! \brief Maximum number of T-bits in a TRAU frame for all speech frames */
+#define MAX_T_BITS	4
+/*! \brief Maximum number of S-bits in a TRAU frame for OM */
+#define MAX_S_BITS	6
+/*! \brief Maximum number of M-bits in a TRAU frame  for E-data */
+#define MAX_M_BITS	2
+/*! \brief Maximum number of XC-bits in a TRAU frame for 8k */
+#define MAX_XC_BITS	6
+
+/*! 16k sub-slot types: Bits C1..C5 */
+#define TRAU_FT_FR_UP		0x02	/* 0 0 0 1 0 - 3.5.1.1.1 */
+#define TRAU_FT_HR_UP		0x03	/* 0 0 0 1 1 - TS 08.61 5.1.4.1.1 */
+#define TRAU_FT_FR_DOWN		0x1c	/* 1 1 1 0 0 - 3.5.1.1.1 */
+#define TRAU_FT_HR_DOWN		0x1d	/* 1 1 1 0 1 - TS 08.61 5.1.4.1.1 */
+#define TRAU_FT_EFR		0x1a	/* 1 1 0 1 0 - 3.5.1.1.1 */
+#define TRAU_FT_AMR		0x06	/* 0 0 1 1 0 - 3.5.1.2 */
+#define TRAU_FT_OM_UP		0x05	/* 0 0 1 0 1 - 3.5.2 */
+#define TRAU_FT_OM_DOWN		0x1b	/* 1 1 0 1 1 - 3.5.2 */
+#define TRAU_FT_DATA_UP		0x08	/* 0 1 0 0 0 - 3.5.3 */
+#define TRAU_FT_DATA_UP_HR	0x09	/* 0 1 0 0 1 - TS 08.61 5.1.4.2 */
+#define TRAU_FT_DATA_DOWN	0x16	/* 1 0 1 1 0 - 3.5.3 */
+#define TRAU_FT_DATA_DOWN_HR	0x17	/* 1 0 1 1 1 - TS 08.61 5.1.4.2 */
+#define TRAU_FT_D145_SYNC	0x14	/* 1 0 1 0 0 - 3.5.3 */
+#define TRAU_FT_EDATA		0x1f	/* 1 1 1 1 1 - 3.5.4 */
+#define TRAU_FT_IDLE_UP		0x10	/* 1 0 0 0 0 - 3.5.5 */
+#define TRAU_FT_IDLE_DOWN	0x0e	/* 0 1 1 1 0 - 3.5.5 */
+
+/* 8k sub-slot types: Bits C1..C5*/
+#define TRAU8_FT_SPEECH_UP	0x02	/* 0 0 0 1 P - TS 08.61 5.2.4.1.1 */
+#define TRAU8_FT_DATA_UP	0x06	/* 0 0 1 1 P - TS 08.61 5.2.4.1.1 */
+#define TRAU8_FT_OM_UP		0x0a	/* 0 1 0 1 P - TS 08.61 5.2.4.1.1 */
+#define TRAU8_FT_SPEECH_DOWN	0x00	/* 0 0 0 U P - TS 08.61 5.2.4.1.2 */
+#define TRAU8_FT_DATA_DOWN	0x04	/* 0 0 1 U P - TS 08.61 5.2.4.1.2 */
+#define TRAU8_FT_OM_DOWN	0x08	/* 0 1 0 U P - TS 08.61 5.2.4.1.2 */
+
+/*********************************************************************************
+ * New API
+ *********************************************************************************/
+
+enum osmo_trau_frame_type {
+	OSMO_TRAU_FT_NONE,
+	OSMO_TRAU16_FT_FR = 1,
+	OSMO_TRAU16_FT_HR,
+	OSMO_TRAU16_FT_EFR,
+	OSMO_TRAU16_FT_AMR,
+	OSMO_TRAU16_FT_OAM,
+	OSMO_TRAU16_FT_DATA,
+	OSMO_TRAU16_FT_EDATA,
+	OSMO_TRAU16_FT_D145_SYNC,
+	OSMO_TRAU16_FT_DATA_HR,
+	OSMO_TRAU16_FT_IDLE,
+
+	OSMO_TRAU8_SPEECH,
+	OSMO_TRAU8_DATA,
+	OSMO_TRAU8_OAM,
+	OSMO_TRAU8_AMR_LOW,
+	OSMO_TRAU8_AMR_6k7,
+	OSMO_TRAU8_AMR_7k4,
+};
+
+extern const struct value_string osmo_trau_frame_type_names[];
+static inline const char *osmo_trau_frame_type_name(enum osmo_trau_frame_type ft) {
+	return get_value_string(osmo_trau_frame_type_names, ft);
+}
+
+enum osmo_trau_frame_direction {
+	OSMO_TRAU_DIR_UL	= 0,
+	OSMO_TRAU_DIR_DL	= 1,
+};
+
+struct osmo_trau_frame {
+	enum osmo_trau_frame_type type;
+	enum osmo_trau_frame_direction dir;
+
+	ubit_t c_bits[MAX_C_BITS];
+	ubit_t d_bits[MAX_D_BITS];
+	ubit_t t_bits[MAX_T_BITS];
+	ubit_t s_bits[MAX_S_BITS];
+	ubit_t m_bits[MAX_M_BITS];
+	ubit_t ufi;			/*!< Unreliable Frame Indication (HR) */
+	ubit_t crc_bits[3];		/*!< CRC0..CRC2 (HR) */
+	ubit_t xc_bits[MAX_XC_BITS];	/*!< XC1..XC6 (8k) */
+};
+
+/*! decode an 8k TRAU frame
+ *  \param[out] fr caller-allocated output data structure
+ *  \param[in] bits unpacked input bits
+ *  \param[in] dir direction
+ *  \return 0 on success; negative in case of error */
+int osmo_trau_frame_decode_8k(struct osmo_trau_frame *fr, const ubit_t *bits,
+			      enum osmo_trau_frame_direction dir);
+
+/*! decode an 16k TRAU frame
+ *  \param[out] fr caller-allocated output data structure
+ *  \param[in] bits unpacked input bits
+ *  \param[in] dir direction
+ *  \return 0 on success; negative in case of error */
+int osmo_trau_frame_decode_16k(struct osmo_trau_frame *fr, const ubit_t *bits,
+			       enum osmo_trau_frame_direction dir);
+
+/*! encode a TRAU frame
+ *  \param[out] bits caller-allocated memory for unpacked output bits
+ *  \param[out] fr input data structure describing TRAU frame
+ *  \return number of bits encoded */
+int osmo_trau_frame_encode(ubit_t *bits, size_t n_bits, const struct osmo_trau_frame *fr);
+
+
+/* }@ */
diff --git a/src/Makefile.am b/src/Makefile.am
index 3838a5a..d1743af 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -35,4 +35,5 @@
 libosmotrau_la_CFLAGS = $(AM_CFLAGS) $(ORTP_CFLAGS)
 libosmotrau_la_LDFLAGS = $(AM_LDFLAGS) -version-info $(TRAU_LIBVERSION)
 libosmotrau_la_LIBADD = $(COMMONLIBS) $(ORTP_LIBS)
-libosmotrau_la_SOURCES = trau/osmo_ortp.c
+libosmotrau_la_SOURCES = trau/osmo_ortp.c \
+			 trau/trau_frame.c
diff --git a/src/trau/trau_frame.c b/src/trau/trau_frame.c
new file mode 100644
index 0000000..a57d642
--- /dev/null
+++ b/src/trau/trau_frame.c
@@ -0,0 +1,1364 @@
+/* New (2020) TRAU frame handling according to GSM TS 48.060 + 48.061 */
+
+/* (C) 2020 by Harald Welte <laforge at gnumonks.org>
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: AGPL-3.0+
+ *
+ * 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 "internal.h"
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include <osmocom/trau/trau_frame.h>
+#include <osmocom/core/logging.h>
+
+/*! \addtogroup trau_frame
+ *  @{
+ *
+ *  \file trau_frame.c
+ */
+
+static uint32_t get_bits(const ubit_t *bitbuf, int offset, int num)
+{
+	int i;
+	uint32_t ret = 0;
+
+	for (i = offset; i < offset + num; i++) {
+		ret = ret << 1;
+		if (bitbuf[i])
+			ret |= 1;
+	}
+	return ret;
+}
+
+const struct value_string osmo_trau_frame_type_names[] = {
+	{ OSMO_TRAU_FT_NONE,		"NONE" },
+	{ OSMO_TRAU16_FT_FR,		"FR" },
+	{ OSMO_TRAU16_FT_HR,		"HR" },
+	{ OSMO_TRAU16_FT_EFR,		"EFR" },
+	{ OSMO_TRAU16_FT_AMR,		"AMR" },
+	{ OSMO_TRAU16_FT_OAM,		"OAM" },
+	{ OSMO_TRAU16_FT_DATA,		"DATA" },
+	{ OSMO_TRAU16_FT_EDATA,		"EDATA" },
+	{ OSMO_TRAU16_FT_D145_SYNC,	"D145_SYNC" },
+	{ OSMO_TRAU16_FT_DATA_HR,	"DATA_HR" },
+	{ OSMO_TRAU16_FT_IDLE,		"IDLE" },
+	{ OSMO_TRAU8_SPEECH,		"8SPEECH" },
+	{ OSMO_TRAU8_DATA,		"8DATA" },
+	{ OSMO_TRAU8_OAM,		"8OAM" },
+	{ OSMO_TRAU8_AMR_LOW,		"8AMR_LOW" },
+	{ OSMO_TRAU8_AMR_6k7,		"8AMR_6k7" },
+	{ OSMO_TRAU8_AMR_7k4,		"8AMR_7k4" },
+	{ 0, NULL }
+};
+
+/*********************************************************************************
+ * New API; introduced in 2020 for use by osmo-mgw
+ *********************************************************************************/
+
+/* 16k sub-slots */
+static const ubit_t ft_fr_up_bits[5] =		{ 0, 0, 0, 1, 0 };
+static const ubit_t ft_fr_down_bits[5] =	{ 1, 1, 1, 0, 0 };
+static const ubit_t ft_data_up_bits[5] =	{ 0, 1, 0, 0, 0 };
+static const ubit_t ft_data_down_bits[5] =	{ 1, 0, 1, 1, 0 };
+static const ubit_t ft_idle_up_bits[5] =	{ 1, 0, 0, 0, 0 };
+static const ubit_t ft_idle_down_bits[5] =	{ 0, 1, 1, 1, 0 };
+static const ubit_t ft_efr_bits[5] =		{ 1, 1, 0, 1, 0 };
+static const ubit_t ft_amr_bits[5] =		{ 0, 0, 1, 1, 0 };
+static const ubit_t ft_oam_up_bits[5] = 	{ 0, 0, 1, 0, 1 };
+static const ubit_t ft_oam_down_bits[5] =	{ 1, 1, 0, 1, 1 };
+static const ubit_t ft_d145s_bits[5] =		{ 1, 0, 1, 0, 0 };
+static const ubit_t ft_edata_bits[5] =		{ 1, 1, 1, 1, 1 };
+
+/* 8k sub-slots */
+static const ubit_t ft_hr_up_bits[5] =		{ 0, 0, 0, 1, 1 };
+static const ubit_t ft_hr_down_bits[5] =	{ 1, 1, 1, 0, 1 };
+static const ubit_t ft_data_hr_up_bits[5] =	{ 0, 1, 0, 0, 1 };
+static const ubit_t ft_data_hr_down_bits[5] =	{ 1, 0, 1, 1, 1 };
+
+
+/* generate the sync pattern described in TS 08.60 4.8.1 */
+static void encode_sync16(ubit_t *trau_bits)
+{
+	int i;
+
+	/* 16 '0' bits in  header */
+	memset(trau_bits, 0, 16);
+	/* '1'-bit in regular intervals */
+	for (i = 16; i < 40*8; i += 16)
+		trau_bits[i] = 1;
+}
+
+#define T16_500us	8	/* 500 us = 8 bits */
+#define T16_250us	4	/* 250 us = 4 bits */
+
+/* How many 16k bits to delay / advance (TS 48.060 Section 5.5.1.1.1) */
+static int fr_efr_alignment_bitcount(uint8_t c6_11)
+{
+	if (c6_11 <= 0x27)
+		return c6_11 * T16_500us;	/* delay frame N x 500us */
+	else if (c6_11 == 0x3e)
+		return T16_250us;		/* delay frame 250us */
+	else if (c6_11 == 0x3f)
+		return -T16_250us;		/* advance frame 250us */
+	else
+		return 0;
+}
+
+/* TS 08.60 Section 3.1.1 */
+static int encode16_fr(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	const ubit_t *cbits5;
+	int i;
+	int d_idx = 0;
+
+	switch (fr->type) {
+	case OSMO_TRAU16_FT_IDLE:
+		if (fr->dir == OSMO_TRAU_DIR_UL)
+			cbits5 = ft_idle_up_bits;
+		else
+			cbits5 = ft_idle_down_bits;
+		break;
+	case OSMO_TRAU16_FT_FR:
+		if (fr->dir == OSMO_TRAU_DIR_UL)
+			cbits5 = ft_fr_up_bits;
+		else
+			cbits5 = ft_fr_down_bits;
+		break;
+	case OSMO_TRAU16_FT_EFR:
+		cbits5 = ft_efr_bits;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	encode_sync16(trau_bits);
+
+	/* C1 .. C5 */
+	memcpy(trau_bits + 17, cbits5 + 0, 5);
+	/* C6 .. C15 */
+	memcpy(trau_bits + 17 + 5, fr->c_bits + 5, 15 - 5);
+	/* D1 .. D255 */
+	for (i = 32; i < 304; i += 16) {
+		trau_bits[i] = 1;
+		memcpy(trau_bits + i + 1, fr->d_bits + d_idx, 15);
+		d_idx += 15;
+	}
+	/* D256 .. D260 */
+	trau_bits[304] = 1;
+	memcpy(trau_bits + 305, fr->d_bits + d_idx, 5);
+	/* C16 .. C21 */
+	memcpy(trau_bits + 310, fr->c_bits + 15, 6);
+
+	/* T1 .. T4 */
+	memcpy(trau_bits + 316, fr->t_bits+0, 4);
+
+	/* handle timing adjustment */
+	if (fr->dir == OSMO_TRAU_DIR_DL) {
+		uint8_t cbits6_11 = get_bits(fr->c_bits, 5, 6);
+		int ta_bits = fr_efr_alignment_bitcount(cbits6_11);
+		if (ta_bits > 0) {
+			memset(trau_bits+320, 1, ta_bits);
+			return 320 + ta_bits;
+		} else if (ta_bits < 0)
+			return 320 - ta_bits;
+	}
+	return 40 * 8;
+}
+
+/* TS 08.60 Section 3.1.1 */
+static int decode16_fr(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			enum osmo_trau_frame_direction dir)
+{
+	int i;
+	int d_idx = 0;
+
+	/* C1 .. C15 */
+	memcpy(fr->c_bits + 0, trau_bits + 17, 15);
+	/* C16 .. C21 */
+	memcpy(fr->c_bits + 15, trau_bits + 310, 6);
+	/* T1 .. T4 */
+	memcpy(fr->t_bits + 0, trau_bits + 316, 4);
+	/* D1 .. D255 */
+	for (i = 32; i < 304; i+= 16) {
+		memcpy(fr->d_bits + d_idx, trau_bits + i + 1, 15);
+		d_idx += 15;
+	}
+	/* D256 .. D260 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 305, 5);
+
+	return 0;
+}
+
+/* TS 08.60 Section 3.1.2 */
+static int encode16_amr(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	const ubit_t *cbits5 = ft_amr_bits;
+	int i, d_idx;
+
+	encode_sync16(trau_bits);
+
+	/* C1 .. C5 */
+	memcpy(trau_bits + 17, cbits5 + 0, 5);
+	/* C6 .. C15 */
+	memcpy(trau_bits + 17 + 5, fr->c_bits + 5, 15 - 5);
+
+	trau_bits[32] = 1;
+	/* C16 .. C25 */
+	memcpy(trau_bits + 33, fr->c_bits + 15, 10);
+	/* D1 .. D5 */
+	memcpy(trau_bits + 43, fr->d_bits + 0, 5);
+
+	/* D6 .. D256 */
+	for (i = 48, d_idx = 5; i <= 315; i += 16, d_idx += 15) {
+		trau_bits[i] = 1;
+		memcpy(trau_bits + i + 1, fr->d_bits + d_idx, 15);
+	}
+
+	/* T1 .. T4 */
+	memcpy(trau_bits + 316, fr->t_bits + 0, 4);
+
+	/* handle timing adjustment */
+	if (fr->dir == OSMO_TRAU_DIR_DL) {
+		uint8_t cbits6_11 = get_bits(fr->c_bits, 5, 6);
+		int ta_bits = fr_efr_alignment_bitcount(cbits6_11);
+		if (ta_bits > 0) {
+			memset(trau_bits+320, 1, ta_bits);
+			return 320 + ta_bits;
+		} else if (ta_bits < 0)
+			return 320 - ta_bits;
+	}
+	/* FIXME: handle TAE (Timing Alignment Extension) */
+	return 40 * 8;
+}
+
+/* TS 08.60 Section 3.1.2 */
+static int decode16_amr(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			enum osmo_trau_frame_direction dir)
+{
+	int i;
+	int d_idx = 0;
+
+	/* C1 .. C15 */
+	memcpy(fr->c_bits + 0, trau_bits + 17, 15);
+	/* C16 .. C25 */
+	memcpy(fr->c_bits + 15, trau_bits + 33, 10);
+	/* T1 .. T4 */
+	memcpy(fr->t_bits + 0, trau_bits + 316, 4);
+	/* D1 .. D5 */
+	memcpy(fr->d_bits, trau_bits + 43, 5);
+	d_idx += 5;
+	/* D6 .. D245 */
+	for (i = 48; i < 304; i += 16) {
+		memcpy(fr->d_bits + d_idx, trau_bits + i + 1, 15);
+		d_idx += 15;
+	}
+	/* D246 .. D256 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 305, 11);
+
+	return 0;
+}
+
+/* TS 08.60 Section 3.2 */
+static int encode16_oam(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	const ubit_t *cbits5;
+	int i, d_idx;
+
+	if (fr->dir == OSMO_TRAU_DIR_UL)
+		cbits5 = ft_oam_up_bits;
+	else
+		cbits5 = ft_oam_down_bits;
+
+	encode_sync16(trau_bits);
+
+	/* C1 .. C5 */
+	memcpy(trau_bits + 17, cbits5, 5);
+	/* C6 .. C15 */
+	memcpy(trau_bits + 17 + 5, fr->c_bits, 15 - 5);
+
+	/* D1 .. D255 */
+	for (i = 32, d_idx = 0; i < 304; i += 16, d_idx += 15) {
+		trau_bits[i] = 1;
+		memcpy(trau_bits + i + 1, fr->d_bits + d_idx, 15);
+	}
+	/* D256 .. D264 */
+	memcpy(trau_bits + 305, fr->d_bits + 256, 9);
+
+	/* S1 .. S6 */
+	memcpy(trau_bits + 314, fr->s_bits, 6);
+
+	return 40 * 8;
+}
+
+/* TS 08.60 Section 3.2 */
+static int decode16_oam(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			enum osmo_trau_frame_direction dir)
+{
+	int i, d_idx;
+
+	/* C1 .. C15 */
+	memcpy(fr->c_bits + 0, trau_bits + 17, 15);
+
+	/* D1 .. D255 */
+	for (i = 33, d_idx = 0; i < 312; i+= 16, d_idx += 15)
+		memcpy(fr->d_bits + d_idx, trau_bits + i + 1, 15);
+	/* D256 .. D264 */
+	memcpy(fr->d_bits+d_idx, trau_bits + 305, 9);
+
+	/* S1 .. S6 */
+	memcpy(fr->s_bits, trau_bits + 314, 6);
+
+	return 0;
+}
+
+/* TS 08.61 Section 5.1.1.1 */
+static int encode16_hr(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	int d_idx = 0;
+	const ubit_t *cbits5;
+
+	if (fr->dir == OSMO_TRAU_DIR_UL)
+		cbits5 = ft_hr_up_bits;
+	else
+		cbits5 = ft_hr_down_bits;
+
+	encode_sync16(trau_bits);
+
+	/* C1 .. C5 */
+	memcpy(trau_bits + 17, cbits5, 5);
+	/* C6 .. C15 */
+	memcpy(trau_bits + 17 + 5, fr->c_bits + 5, 10);
+
+	/*  UFI */
+	trau_bits[33] = fr->ufi;
+
+	/* D1 .. D14 */
+	memcpy(trau_bits + 4 * 8 + 2, fr->d_bits+d_idx, 14); d_idx += 14;
+	/* D15 .. D29 */
+	memcpy(trau_bits + 6 * 8 + 1, fr->d_bits+d_idx, 15); d_idx += 15;
+	/* D30 .. D44 */
+	memcpy(trau_bits + 8 * 8 + 1, fr->d_bits+d_idx, 15); d_idx += 15;
+	/* CRC */
+	memcpy(trau_bits + 10 * 8 + 1, fr->crc_bits, 3);
+	/* D45 .. D56 */
+	memcpy(trau_bits + 10 * 8 + 4, fr->d_bits+d_idx, 12); d_idx += 12;
+	/* D57 .. D71 */
+	memcpy(trau_bits + 12 * 8 + 1, fr->d_bits+d_idx, 15); d_idx += 15;
+	/* D72 .. D86 */
+	memcpy(trau_bits + 14 * 8 + 1, fr->d_bits+d_idx, 15); d_idx += 15;
+	/* D87 .. D101 */
+	memcpy(trau_bits + 16 * 8 + 1, fr->d_bits+d_idx, 15); d_idx += 15;
+	/* D102 .. D112 */
+	memcpy(trau_bits + 18 * 8 + 1, fr->d_bits+d_idx, 11); d_idx += 11;
+
+	memset(trau_bits + 19 * 8 + 4, 0x01, 4 + 18 * 8 + 6);
+	/* C16 .. C21 */
+	memcpy(trau_bits + 38 * 8 + 6, fr->c_bits + 15, 6);
+
+	/* T1 .. T4 */
+	memcpy(trau_bits + 39 * 8 + 4, fr->t_bits, 4);
+
+	/* handle timing adjustment */
+	if (fr->dir == OSMO_TRAU_DIR_DL) {
+		uint8_t cbits6_11 = get_bits(fr->c_bits, 5, 6);
+		int ta_bits = fr_efr_alignment_bitcount(cbits6_11);
+		if (ta_bits > 0) {
+			memset(trau_bits+320, 1, ta_bits);
+			return 320 + ta_bits;
+		} else if (ta_bits < 0)
+			return 320 - ta_bits;
+	}
+	return 40 * 8;
+}
+
+/* TS 08.61 Section 5.1.1.1 */
+static int decode16_hr(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			enum osmo_trau_frame_direction dir)
+{
+	int d_idx = 0;
+
+	/* C1 .. C15 */
+	memcpy(fr->c_bits + 0, trau_bits + 17, 15);
+	/* C16 .. C21 */
+	memcpy(fr->c_bits + 15, trau_bits + 38 * 8 + 6, 6);
+	/* T1 .. T4 */
+	memcpy(fr->t_bits + 0, trau_bits + 39 * 8 + 4, 4);
+
+	/* UFI */
+	fr->ufi = trau_bits[33];
+	/* D1 .. D14 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 4 * 8 + 2, 14); d_idx += 14;
+	/* D15 .. D29 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 6 * 8 + 1, 15); d_idx += 15;
+	/* D30 .. D44 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 8 * 8 + 1, 15); d_idx += 15;
+	/* CRC0..2 */
+	memcpy(fr->crc_bits, trau_bits + 10 * 8 + 1, 3);
+	/* D45 .. D56 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 10 * 8 + 4, 12); d_idx += 12;
+	/* D57 .. D71 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 12 * 8 + 1, 15); d_idx += 15;
+	/* D72 .. D86 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 14 * 8 + 1, 15); d_idx += 15;
+	/* D87 .. D101 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 16 * 8 + 1, 15); d_idx += 15;
+	/* D102 .. D112 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 18 * 8 + 1, 11); d_idx += 11;
+
+	return 0;
+}
+
+static struct osmo_trau_frame fr_idle_frame = {
+	.type = OSMO_TRAU16_FT_IDLE,
+	.dir = OSMO_TRAU_DIR_DL,
+	.t_bits = { 1, 1, 1, 1 },
+};
+#define TRAU_FRAME_BITS (40*8)
+static ubit_t encoded_idle_frame[TRAU_FRAME_BITS];
+static int dbits_initted = 0;
+
+/*! \brief return pointer to global buffer containing a TRAU idle frame */
+static ubit_t *trau_idle_frame(void)
+{
+	/* only initialize during the first call */
+	if (!dbits_initted) {
+		/* set all D-bits to 1 */
+		memset(&fr_idle_frame.d_bits, 0x01, 260);
+
+		memset(&fr_idle_frame.c_bits, 0x01, 25); /* spare are set to 1 */
+		/* set Downlink Idle Speech Frame pattern */
+		fr_idle_frame.c_bits[0] = 0; /* C1 */
+		fr_idle_frame.c_bits[1] = 1; /* C2 */
+		fr_idle_frame.c_bits[2] = 1; /* C3 */
+		fr_idle_frame.c_bits[3] = 1; /* C4 */
+		fr_idle_frame.c_bits[4] = 0; /* C5 */
+		/* set no Time Alignment pattern */
+		fr_idle_frame.c_bits[5] = 0; /* C6 */
+		fr_idle_frame.c_bits[6] = 0; /* C7 */
+		fr_idle_frame.c_bits[7] = 0; /* C8 */
+		fr_idle_frame.c_bits[8] = 0; /* C9 */
+		fr_idle_frame.c_bits[9] = 0; /* C10 */
+		fr_idle_frame.c_bits[10] = 0; /* C11 */
+		/* already set to 1, but maybe we need to modify it in the future */
+		fr_idle_frame.c_bits[11] = 1; /* C12 (UFE), good frame */
+		fr_idle_frame.c_bits[15] = 1; /* C16 (SP), no DTX */
+
+		encode16_fr(encoded_idle_frame, &fr_idle_frame);
+		dbits_initted = 1; /* set it to 1 to not call it again */
+	}
+	return encoded_idle_frame;
+}
+
+/* TS 08.60 Section 3.4 */
+static int encode16_idle(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	memcpy(trau_bits, trau_idle_frame(), 40*8);
+	return 40 * 8;
+}
+
+/* TS 08.60 Section 3.3.1 */
+static int decode16_data(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			 enum osmo_trau_frame_direction dir)
+{
+	int i, d_idx = 0;
+
+	/* C1 .. C15 */
+	memcpy(fr->c_bits + 0, trau_bits + 17, 15);
+
+	/* D1 .. D63 */
+	for (i = 0; i < 9; i++) {
+		memcpy(fr->d_bits + d_idx, trau_bits + (4 + i) * 8 + 1, 7);
+		d_idx += 7;
+	}
+	/* D64 .. D126 */
+	for (i = 0; i < 9; i++) {
+		memcpy(fr->d_bits + d_idx, trau_bits + (13 + i) * 8 + 1, 7);
+		d_idx += 7;
+	}
+
+	/* D127 .. D189 */
+	for (i = 0; i < 9; i++) {
+		memcpy(fr->d_bits + d_idx, trau_bits + (22 + i) * 8 + 1, 7);
+		d_idx += 7;
+	}
+
+	/* D190 .. D252 */
+	for (i = 0; i < 9; i++) {
+		memcpy(fr->d_bits + d_idx, trau_bits + (31 + i) * 8 + 1, 7);
+		d_idx += 7;
+	}
+
+	return 0;
+}
+
+/* TS 08.60 Section 3.3.1 */
+static int encode16_data(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	const ubit_t *cbits5;
+	int i, d_idx = 0;
+
+	if (fr->dir == OSMO_TRAU_DIR_UL)
+		cbits5 = ft_data_up_bits;
+	else
+		cbits5 = ft_data_down_bits;
+
+	encode_sync16(trau_bits);
+
+	/* C1 .. C5 */
+	memcpy(trau_bits + 17, cbits5, 5);
+	/* C6 .. C15 */
+	memcpy(trau_bits + 17 + 5, fr->c_bits + 5, 15 - 5);
+
+	/* D1 .. D63 */
+	for (i = 0; i < 9; i++) {
+		unsigned int offset = (4 + i) * 8;
+		trau_bits[offset] = 1;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+
+	/* D64 .. D126 */
+	for (i = 0; i < 9; i++) {
+		unsigned int offset = (13 + i) * 8;
+		trau_bits[offset] = 1;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+
+	/* D127 .. D189 */
+	for (i = 0; i < 9; i++) {
+		unsigned int offset = (22 + i) * 8;
+		trau_bits[offset] = 1;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+
+	/* D190 .. D252 */
+	for (i = 0; i < 9; i++) {
+		unsigned int offset = (31 + i) * 8;
+		trau_bits[offset] = 1;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+
+	return 40 * 8;
+}
+
+/* TS 08.60 3.3.2 */
+static int decode16_edata(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			  enum osmo_trau_frame_direction dir)
+{
+	/* C1 .. C13 */
+	memcpy(fr->c_bits, trau_bits + 17, 13);
+
+	/* M1 .. M2 */
+	memcpy(fr->m_bits, trau_bits + 30, 2);
+
+	/* D1 .. D288 */
+	memcpy(fr->d_bits, trau_bits + 4 * 8, 288);
+
+	return 0;
+}
+
+/* TS 08.60 Section 3.3.2 */
+static int encode16_edata(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	const ubit_t *cbits5;
+
+	if (fr->type == OSMO_TRAU16_FT_D145_SYNC)
+		cbits5 = ft_d145s_bits;
+	else
+		cbits5 = ft_edata_bits;
+
+	/* C1 .. C5 */
+	memcpy(trau_bits + 17, cbits5, 5);
+
+	/* C6 .. C13 */
+	memcpy(trau_bits + 17 + 5, fr->c_bits + 5, 8);
+
+	/* M1 .. M2 */
+	memcpy(trau_bits + 30, fr->m_bits, 2);
+
+	/* D1 .. D288 */
+	memcpy(trau_bits + 4 * 8, fr->d_bits, 288);
+
+	return 40 * 8;
+}
+
+/* TS 08.61 Section 5.1.2 */
+static int decode16_data_hr(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			  enum osmo_trau_frame_direction dir)
+{
+	int i, d_idx = 0;
+
+	/* C1 .. C15 */
+	memcpy(fr->c_bits+0, trau_bits + 17, 15);
+
+	/* D1 .. D63 */
+	for (i = 0; i < 9; i++) {
+		memcpy(fr->d_bits + d_idx, trau_bits + (4 + i) * 8 + 1, 7);
+		d_idx += 7;
+	}
+
+	/* D'1 .. D'63 (mapped to D64..D127) */
+	for (i = 0; i < 9; i++) {
+		memcpy(fr->d_bits + d_idx, trau_bits + (22 + i) * 8 + 1, 7);
+		d_idx += 7;
+	}
+
+	return 0;
+}
+
+/* TS 08.61 Section 5.1.2 */
+static int encode16_data_hr(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	const ubit_t *cbits5;
+	int i, d_idx = 0;
+
+	if (fr->dir == OSMO_TRAU_DIR_UL)
+		cbits5 = ft_data_hr_up_bits;
+	else
+		cbits5 = ft_data_hr_down_bits;
+
+	encode_sync16(trau_bits);
+
+	/* C1 .. C5 */
+	memcpy(trau_bits + 17, cbits5, 5);
+	/* C6 .. C15 */
+	memcpy(trau_bits + 17 + 5, fr->c_bits + 5, 15 - 5);
+
+	/* D1 .. D63 */
+	for (i = 4; i < 4 + 9; i++) {
+		unsigned int offset = i * 8;
+		trau_bits[offset] = 1;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+
+	memset(trau_bits + 13*8, 1, 9*8);
+
+	/* D'1 .. D'63 (mapped to D64..D127) */
+	for (i = 22; i < 22 + 9; i++) {
+		unsigned int offset = i * 8;
+		trau_bits[offset] = 1;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+
+	memset(trau_bits + 31*8, 1, 9*8);
+
+	return 40 * 8;
+}
+
+/* TS 08.61 Section 5.2.1.1 */
+static int decode8_hr(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+		      enum osmo_trau_frame_direction dir)
+{
+	int i, d_idx = 0;
+
+	/* C1 .. C5 */
+	memcpy(fr->c_bits, trau_bits + 9, 5);
+	/* XC1 .. XC2 */
+	memcpy(fr->xc_bits, trau_bits + 8 + 6, 2);
+	/* XC3 .. XC6 */
+	memcpy(fr->xc_bits + 2, trau_bits + 2 * 8 + 2, 4);
+	/* D1 .. D2 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 2 * 8 + 6, 2);
+	d_idx += 2;
+
+	/* D1 .. D44 */
+	for (i = 3; i < 3 + 6; i++) {
+		int offset = i * 8;
+		memcpy(fr->d_bits + d_idx, trau_bits + offset + 1, 7);
+		d_idx += 7;
+	}
+
+	/* CRC0 .. CRC2 */
+	fr->crc_bits[2] = trau_bits[82];
+	fr->crc_bits[1] = trau_bits[83];
+	fr->crc_bits[0] = trau_bits[84];
+
+	/* D45 .. D48 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 85, 4);
+
+	/* D49 .. D111 */
+	for (i = 10; i < 10 + 10; i++) {
+		int offset = i * 8;
+		memcpy(fr->d_bits + d_idx, trau_bits + offset + 1, 7);
+		d_idx += 7;
+	}
+	/* D112 */
+	fr->d_bits[d_idx++] = trau_bits[19 * 8 + 1];
+
+	/* C6 .. C9 */
+	memcpy(fr->c_bits + 5, trau_bits + 19 * 8 + 2, 4);
+
+	/* T1 .. T2 */
+	fr->t_bits[0] = trau_bits[19 * 8 + 6];
+	fr->t_bits[1] = trau_bits[19 * 8 + 7];
+
+	return 0;
+}
+
+/* compute the odd parity bit of the given input bit sequence */
+static ubit_t compute_odd_parity(const ubit_t *in, unsigned int num_bits)
+{
+	int i;
+	unsigned int sum = 0;
+
+	for (i = 0; i < num_bits; i++) {
+		if (in[i])
+			sum++;
+	}
+
+	if (sum % 1)
+		return 0;
+	else
+		return 1;
+}
+
+/* TS 08.61 Section 5.2.1.1 */
+static int encode8_hr(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	int i, d_idx = 0;
+
+	/* sync pattern */
+	memset(trau_bits, 0, 8);
+	trau_bits[8] = 1;
+	trau_bits[16] = 0;
+	trau_bits[17] = 1;
+	for (i = 3; i < 20; i++)
+		trau_bits[i * 8] = 1;
+
+	/* C1 .. C5 */
+	ubit_t *cbits_out = trau_bits + 1 * 8 + 1;
+	if (fr->dir == OSMO_TRAU_DIR_UL) {
+		cbits_out[0] = 0;
+		cbits_out[1] = 0;
+		cbits_out[2] = 0;
+		cbits_out[3] = 1;
+		cbits_out[4] = 1;
+	} else {
+		cbits_out[0] = 0;
+		cbits_out[1] = 0;
+		cbits_out[2] = 0;
+		cbits_out[3] = fr->c_bits[3];
+		cbits_out[4] = compute_odd_parity(cbits_out, 4);
+	}
+
+	/* XC1 .. XC2 */
+	memcpy(trau_bits + 1 * 8 + 6, fr->xc_bits, 2);
+	/* XC3 .. XC6 */
+	memcpy(trau_bits + 2 * 8 + 2, fr->xc_bits, 4);
+	/* D1 ..  D2 */
+	memcpy(trau_bits + 2 * 8 + 6, fr->d_bits, 2);
+	d_idx += 2;
+
+	/* D1 .. D44 */
+	for (i = 3; i < 3 + 6; i++) {
+		int offset = i * 8;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	};
+
+	/* CRC0 .. CRC2 */
+	trau_bits[82] = fr->crc_bits[2];
+	trau_bits[83] = fr->crc_bits[1];
+	trau_bits[84] = fr->crc_bits[0];
+
+	/* D49 .. D111 */
+	for (i = 10; i < 10 + 10; i++) {
+		int offset = i * 8;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+	/* D112 */
+	trau_bits[19 * 8 + 1] = fr->d_bits[d_idx++];
+
+	/* C6 .. C9 */
+	memcpy(trau_bits + 19 * 8 + 2, fr->c_bits + 5, 4);
+
+	/* FIXME: handle timing adjustment */
+	/* T1 .. T2 */
+	trau_bits[19 * 8 + 6] = fr->t_bits[0];
+	trau_bits[19 * 8 + 7] = fr->t_bits[1];
+
+	return 20 * 8;
+}
+
+/* TS 08.61 Section 5.2.1.2.1 */
+static int decode8_amr_low(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			   enum osmo_trau_frame_direction dir)
+{
+	int i, d_idx = 0;
+
+	/* D1 .. D7 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 1 * 8 + 1, 7);
+	d_idx += 7;
+	/* C1 .. C5 */
+	memcpy(fr->c_bits, trau_bits + 2 * 8 + 1, 5);
+	/* D8 .. D9 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 2 * 8 + 6, 2);
+	d_idx += 2;
+	/* D10 .. D15 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 3 * 8 + 2, 6);
+	d_idx += 6;
+	/* D16 .. D120 */
+	for (i = 4; i < 19; i++) {
+		int offset = i * 8;
+		memcpy(fr->d_bits + d_idx, trau_bits + offset + 1, 7);
+		d_idx += 7;
+	}
+	/* D121 .. D126 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 19 * 8 + 1, 6);
+	d_idx += 6;
+
+	/* T1 */
+	fr->t_bits[0] = trau_bits[19 * 8 + 7];
+
+	return 0;
+}
+
+/* TS 08.61 Section 5.2.1.2.1 */
+static int encode8_amr_low(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	int i, d_idx = 0;
+
+	/* sync pattern */
+	memset(trau_bits, 0, 8);
+	trau_bits[8] = 1;
+	trau_bits[16] = 1;
+	trau_bits[24] = 0;
+	trau_bits[25] = 1;
+	for (i = 4; i < 20; i++)
+		trau_bits[i * 8] = 1;
+
+	/* D1 .. D7 */
+	memcpy(trau_bits + 1 * 8 + 1, fr->d_bits + d_idx, 7);
+	d_idx += 7;
+	/* C1 .. C5 */
+	memcpy(trau_bits + 2 * 8 + 1, fr->c_bits, 5);
+	/* D8 .. D9 */
+	memcpy(trau_bits + 2 * 8 + 6, fr->d_bits + d_idx, 2);
+	d_idx += 2;
+	/* D10 .. D15 */
+	memcpy(trau_bits + 3 * 8 + 2, fr->d_bits + d_idx, 6);
+	d_idx += 6;
+	/* D16 .. D120 */
+	for (i = 4; i < 19; i++) {
+		int offset = i * 8;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+	/* D121 .. D126 */
+	memcpy(trau_bits + 19 * 8 + 1, fr->d_bits + d_idx, 6);
+	d_idx += 6;
+
+	/* T1 */
+	trau_bits[19 * 8 + 7] = fr->t_bits[0];
+
+	return 20 * 8;
+}
+
+/* TS 08.61 Section 5.2.1.2.2 */
+static int decode8_amr_67(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			  enum osmo_trau_frame_direction dir)
+{
+	int i, d_idx = 0;
+
+	/* D1 .. D7 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 1 * 8 + 1, 7);
+	d_idx += 7;
+	/* C1 .. C3 */
+	memcpy(fr->c_bits, trau_bits + 2 * 8 + 1, 3);
+	/* D8 .. D11 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 2 * 8 + 4, 4);
+	d_idx += 4;
+	/* D12 .. D39 */
+	for (i = 3; i < 7; i++) {
+		int offset = i * 8;
+		memcpy(fr->d_bits + d_idx, trau_bits + offset + 2, 7);
+		d_idx += 7;
+	}
+
+	/* D40 .. D137 */
+	for (i = 7; i < 20; i+= 2) {
+		int offset = i * 8;
+		memcpy(fr->d_bits + d_idx, trau_bits + offset + 1, 15);
+		d_idx += 15;
+	}
+
+	return 0;
+}
+
+/* TS 08.61 Section 5.1.2.2 */
+static int encode8_amr_67(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	int i, d_idx = 0;
+
+	/* sync pattern */
+	memset(trau_bits, 0, 8);
+	trau_bits[1 * 8] = 1;
+	trau_bits[2 * 8] = 1;
+	trau_bits[3 * 8] = 1;
+	trau_bits[4 * 8] = 1;
+	trau_bits[5 * 8] = 0;
+	for (i = 5; i < 20; i += 2)
+		trau_bits[i * 8] = 1;
+
+	/* D1 .. D7 */
+	memcpy(trau_bits + 1 * 8 + 1, fr->d_bits + d_idx, 7);
+	d_idx += 7;
+	/* C1 .. C3 */
+	memcpy(trau_bits + 2 * 8 + 1, fr->c_bits, 3);
+	/* D8 .. D11 */
+	memcpy(trau_bits + 2 * 8 + 4, fr->d_bits + d_idx, 4);
+	d_idx += 4;
+	/* D12 .. D39 */
+	for (i = 3; i < 7; i++) {
+		int offset = i * 8;
+		memcpy(trau_bits + offset + 2, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+
+	/* D40 .. D137 */
+	for (i = 7; i < 20; i+= 2) {
+		int offset = i * 8;
+		memcpy(trau_bits + offset + 1, fr->d_bits + d_idx, 15);
+		d_idx += 15;
+	}
+
+	return 20 * 8;
+}
+
+/* TS 08.61 Section 5.1.2.3 */
+static int decode8_amr_74(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			  enum osmo_trau_frame_direction dir)
+{
+	int d_idx = 0;
+
+	/* D1 .. D5 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 3, 5);
+	d_idx += 5;
+	/* D6 .. D12 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 1 * 8 + 1, 7);
+	d_idx += 7;
+	/* C1.. C3 */
+	memcpy(fr->c_bits, trau_bits + 2 * 8 + 1, 3);
+	/* D13 .. D16 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 2 * 8 + 4, 4);
+	d_idx += 4;
+	/* D17 .. D23 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 3 * 8 + 1, 7);
+	d_idx += 7;
+	/* D24 .. D151 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 4 * 8, 16 * 8);
+
+	return 0;
+}
+
+/* TS 08.61 Section 5.1.2.3 */
+static int encode8_amr_74(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	int d_idx = 0;
+
+	/* sync pattern */
+	trau_bits[0] = 0;
+	trau_bits[1] = 0;
+	trau_bits[2] = 1;
+	trau_bits[1*8] = 0;
+	trau_bits[2*8] = 1;
+	trau_bits[3*8] = 0;
+
+	/* D1 .. D5 */
+	memcpy(trau_bits + 3, fr->d_bits + d_idx, 5);
+	d_idx += 5;
+	/* D6 .. D12 */
+	memcpy(trau_bits + 1 * 8 + 1, fr->d_bits + d_idx, 7);
+	d_idx += 7;
+	/* C1.. C3 */
+	memcpy(trau_bits + 2 * 8 + 1, fr->c_bits, 3);
+	/* D13 .. D16 */
+	memcpy(trau_bits + 2 * 8 + 4, fr->d_bits + d_idx, 4);
+	d_idx += 4;
+	/* D17 .. D23 */
+	memcpy(trau_bits + 3 * 8 + 1, fr->d_bits + d_idx, 7);
+	d_idx += 7;
+	/* D24 .. D151 */
+	memcpy(trau_bits + 4 * 8, fr->d_bits + d_idx, 16 * 8);
+
+	return 20 * 8;
+}
+
+/* TS 08.61 Section 5.2.2 */
+static int decode8_data(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+			enum osmo_trau_frame_direction dir)
+{
+	int i, d_idx = 0;
+
+	/* C1 .. C5 */
+	memcpy(fr->c_bits, trau_bits + 1 * 8 + 1, 5);
+	/* D1 .. D2 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 1 * 8 + 6, 2);
+	d_idx += 2;
+	/* D3 .. D8 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 2 * 8 + 2, 6);
+	/* D9 .. D57 + D'1 .. D'57 */
+	for (i = 3; i < 20; i++) {
+		memcpy(fr->d_bits + d_idx, trau_bits + i * 8 + 1, 7);
+		d_idx += 7;
+	}
+	/* D'58 .. D'62 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 19 * 8 + 1, 6);
+	d_idx += 6;
+
+	return 0;
+}
+
+/* TS 08.61 Section 5.2.2 */
+static int encode8_data(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	int i, d_idx = 0;
+
+	/* sync pattern */
+	memset(trau_bits, 0, 8);
+	trau_bits[1 * 8] = 1;
+	trau_bits[2 * 8] = 0;
+	trau_bits[2 * 8 + 1] = 1;
+	for (i = 3; i < 19; i++)
+		trau_bits[i * 8] = 1;
+	trau_bits[19 * 8 + 7] = 1;
+
+	/* C1 .. C5 */
+	memcpy(trau_bits + 1 * 8 + 1, fr->c_bits, 5);
+	/* D1 .. D2 */
+	memcpy(trau_bits + 1 * 8 + 6, fr->d_bits + d_idx, 2);
+	d_idx += 2;
+	/* D3 .. D8 */
+	memcpy(trau_bits + 2 * 8 + 2, fr->d_bits + d_idx, 6);
+	/* D9 .. D57 + D'1 .. D'57 */
+	for (i = 3; i < 20; i++) {
+		memcpy(trau_bits + i * 8 + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+	/* D'58 .. D'62 */
+	memcpy(trau_bits + 19 * 8 + 1, fr->d_bits + d_idx, 6);
+	d_idx += 6;
+
+	return 20 * 8;
+}
+
+/* TS 08.61 Section 5.2.3 */
+static int decode8_oam(struct osmo_trau_frame *fr, const ubit_t *trau_bits,
+		       enum osmo_trau_frame_direction dir)
+{
+	int i, d_idx = 0;
+
+	/* C1 .. C5 */
+	memcpy(fr->c_bits, trau_bits + 1 * 8 + 1, 5);
+	/* XC1 .. XC2 */
+	memcpy(fr->xc_bits, trau_bits + 1 * 8 + 6, 2);
+	/* XC3 .. XC6 */
+	memcpy(fr->xc_bits + 2, trau_bits + 2 * 8 + 2, 4);
+	/* D1 .. D2 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 2 * 8 + 6, 2);
+	d_idx += 2;
+	/* D3 .. D114 */
+	for (i = 3; i < 19; i++) {
+		memcpy(fr->d_bits + d_idx, trau_bits + i * 8 + 1, 7);
+		d_idx += 7;
+	}
+	/* D115 .. D120 */
+	memcpy(fr->d_bits + d_idx, trau_bits + 19 * 8 + 1, 6);
+	d_idx += 7;
+
+	return 0;
+}
+
+/* TS 08.61 Section 5.2.3 */
+static int encode8_oam(ubit_t *trau_bits, const struct osmo_trau_frame *fr)
+{
+	int i, d_idx = 0;
+
+	/* sync pattern */
+	memset(trau_bits, 0, 8);
+	trau_bits[1 * 8 + 0] = 1;
+	trau_bits[2 * 8 + 0] = 0;
+	trau_bits[2 * 8 + 1] = 1;
+	for (i = 3; i < 20; i++)
+		trau_bits[i * 8] = 1;
+
+	/* C1 .. C5 */
+	memcpy(trau_bits + 1 * 8 + 1, fr->c_bits, 5);
+	/* XC1 .. XC2 */
+	memcpy(trau_bits + 1 * 8 + 6, fr->xc_bits, 2);
+	/* XC3 .. XC6 */
+	memcpy(trau_bits + 2 * 8 + 2, fr->xc_bits + 2, 4);
+	/* D1 .. D2 */
+	memcpy(trau_bits + 2 * 8 + 6, fr->d_bits + d_idx, 2);
+	d_idx += 2;
+	/* D3 .. D114 */
+	for (i = 3; i < 19; i++) {
+		memcpy(trau_bits + i * 8 + 1, fr->d_bits + d_idx, 7);
+		d_idx += 7;
+	}
+	/* D115 .. D120 */
+	memcpy(trau_bits + 19 * 8 + 1, fr->d_bits + d_idx, 6);
+	d_idx += 7;
+
+	return 20 * 8;
+}
+
+
+/*! Encode a TRAU frame from its decoded representation to a sequence of unpacked bits.
+ *  \param[out] bits caller-allocated buffer for unpacked outpud bits
+ *  \param[in] n_bits size of 'bits' oputput buffer in number of unpacked bits
+ *  \param[in] fr decoded representation of TRAU frame to be encoded
+ *  \return 0 number of unpacked output bits generated; negative in case of error */
+int osmo_trau_frame_encode(ubit_t *bits, size_t n_bits, const struct osmo_trau_frame *fr)
+{
+	switch (fr->type) {
+	case OSMO_TRAU16_FT_FR:
+	case OSMO_TRAU16_FT_EFR:
+		return encode16_fr(bits, fr);
+	case OSMO_TRAU16_FT_HR:
+		return encode16_hr(bits, fr);
+	case OSMO_TRAU16_FT_AMR:
+		return encode16_amr(bits, fr);
+	case OSMO_TRAU16_FT_OAM:
+		return encode16_oam(bits, fr);
+	case OSMO_TRAU16_FT_IDLE:
+		return encode16_idle(bits, fr);
+	case OSMO_TRAU16_FT_DATA_HR:
+		return encode16_data_hr(bits, fr);
+	case OSMO_TRAU16_FT_DATA:
+		return encode16_data(bits, fr);
+	case OSMO_TRAU16_FT_D145_SYNC:
+	case OSMO_TRAU16_FT_EDATA:
+		return encode16_edata(bits, fr);
+	case OSMO_TRAU8_SPEECH:
+		return encode8_hr(bits, fr);
+	case OSMO_TRAU8_DATA:
+		return encode8_data(bits, fr);
+	case OSMO_TRAU8_OAM:
+		return encode8_oam(bits, fr);
+	case OSMO_TRAU8_AMR_LOW:
+		return encode8_amr_low(bits, fr);
+	case OSMO_TRAU8_AMR_6k7:
+		return encode8_amr_67(bits, fr);
+	case OSMO_TRAU8_AMR_7k4:
+		return encode8_amr_74(bits, fr);
+	case OSMO_TRAU_FT_NONE:
+	default:
+		return -EINVAL;
+	}
+}
+
+/*! Decode/parse a 16k TRAU frame from unpacked bits to decoded format.
+ *  \param[out] fr caller-allocated output data structure
+ *  \param[in] bits unpacked bits containing raw TRAU frame; must be aligned
+ *  \param[in] dir direction (uplink/downlink)
+ *  \returns 0 in case of success; negative on error */
+int osmo_trau_frame_decode_16k(struct osmo_trau_frame *fr, const ubit_t *bits,
+			       enum osmo_trau_frame_direction dir)
+{
+	uint8_t cbits5 = get_bits(bits, 17, 5);
+
+	fr->type = OSMO_TRAU_FT_NONE;
+	fr->dir = dir;
+
+	switch (cbits5) {
+	case TRAU_FT_FR_UP:
+	case TRAU_FT_FR_DOWN:
+		fr->type = OSMO_TRAU16_FT_FR;
+		return decode16_fr(fr, bits, dir);
+	case TRAU_FT_IDLE_UP:
+	case TRAU_FT_IDLE_DOWN:
+		fr->type = OSMO_TRAU16_FT_IDLE;
+		return decode16_fr(fr, bits, dir);
+	case TRAU_FT_EFR:
+		fr->type = OSMO_TRAU16_FT_EFR;
+		return decode16_fr(fr, bits, dir);
+	case TRAU_FT_AMR:
+		fr->type = OSMO_TRAU16_FT_AMR;
+		return decode16_amr(fr, bits, dir);
+	case TRAU_FT_OM_UP:
+	case TRAU_FT_OM_DOWN:
+		fr->type = OSMO_TRAU16_FT_OAM;
+		return decode16_oam(fr, bits, dir);
+	case TRAU_FT_DATA_UP:
+	case TRAU_FT_DATA_DOWN:
+		fr->type = OSMO_TRAU16_FT_DATA;
+		return decode16_data(fr, bits, dir);
+	case TRAU_FT_HR_UP:
+	case TRAU_FT_HR_DOWN:
+		fr->type = OSMO_TRAU16_FT_HR;
+		return decode16_hr(fr, bits, dir);
+	case TRAU_FT_DATA_UP_HR:
+	case TRAU_FT_DATA_DOWN_HR:
+		fr->type = OSMO_TRAU16_FT_DATA_HR;
+		return decode16_data_hr(fr, bits, dir);
+	case TRAU_FT_EDATA:
+		fr->type = OSMO_TRAU16_FT_EDATA;
+		return decode16_edata(fr, bits, dir);
+	case TRAU_FT_D145_SYNC:
+		fr->type = OSMO_TRAU16_FT_D145_SYNC;
+		return decode16_edata(fr, bits, dir);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+#define TRAU8_FT_AMR_NO_SPEECH_CMI	0x10	/* 1, 0, 0, 0, 0 */
+#define TRAU8_FT_AMR_NO_SPEECH_CMR	0x14	/* 1, 0, 1, 0, 0 */
+#define TRAU8_FT_AMR_475_515_590	0..7
+
+const uint8_t bit8_0[16] = { 0,  };
+
+/*!< check sync pattern for hr/data/oam */
+static bool is_hr(const ubit_t *bits)
+{
+	int i;
+
+	/* TS 08.61 Section 6.8.2.1.1 */
+	if (memcmp(bits, bit8_0, sizeof(bit8_0)))
+		return false;
+	if (bits[8] != 1)
+		return false;
+	if (bits[16] != 0 || bits[17] != 1)
+		return false;
+	for (i = 24; i < 20 * 8; i += 16) {
+		if (bits[i] != 1)
+			return false;
+	}
+	return true;
+}
+
+
+/*!< check sync pattern for AMR No_Speech + low bit rate */
+static bool is_amr_low(const ubit_t *bits)
+{
+	int i;
+
+	/* TS 08.61 Section 6.8.2.1.2 */
+	if (memcmp(bits, bit8_0, sizeof(bit8_0)))
+		return false;
+	if (bits[8] != 1)
+		return false;
+	if (bits[16] != 1)
+		return false;
+	if (bits[24] != 0 || bits[25] != 1)
+		return false;
+	for (i = 32; i < 20 * 8; i += 16) {
+		if (bits[i] != 1)
+			return false;
+	}
+	return true;
+}
+
+/*!< check sync pattern for AMR 6.7kBit/s */
+static bool is_amr_67(const ubit_t *bits)
+{
+	int i;
+
+	/* TS 08.61 Section 6.8.2.1.3 */
+	if (memcmp(bits, bit8_0, sizeof(bit8_0)))
+		return false;
+	if (bits[8] != 1)
+		return false;
+	if (bits[16] != 1)
+		return false;
+	if (bits[24] != 1)
+		return false;
+	if (bits[32] != 1)
+		return false;
+	if (bits[40] != 0)
+		return false;
+	for (i = 48; i < 20 * 8; i+= 16)
+		if (bits[i] != 1)
+			return false;
+
+	return true;
+}
+
+/*!< check sync pattern for AMR 7.4kBit/s */
+static bool is_amr_74(const ubit_t *bits)
+{
+	if (bits[0] != 0 || bits[1] != 0 || bits[2] != 0)
+		return false;
+	if (bits[8] != 0)
+		return false;
+	if (bits[16] != 1)
+		return false;
+	if (bits[24] != 0)
+		return false;
+
+	return true;
+}
+
+/*! Decode/parse a 8k TRAU frame from unpacked bits to decoded format.
+ *  \param[out] fr caller-allocated output data structure
+ *  \param[in] bits unpacked bits containing raw TRAU frame; must be aligned
+ *  \param[in] dir direction (uplink/downlink)
+ *  \returns 0 in case of success; negative on error */
+int osmo_trau_frame_decode_8k(struct osmo_trau_frame *fr, const ubit_t *bits,
+			      enum osmo_trau_frame_direction dir)
+{
+	fr->type = OSMO_TRAU_FT_NONE;
+	fr->dir = dir;
+
+	if (is_hr(bits)) {
+		/* normal sync pattern */
+		uint8_t cbits5 = get_bits(bits, 9, 5);
+		if (dir == OSMO_TRAU_DIR_UL) {
+			switch (cbits5) {	/* Section 5.2.4.1.1 */
+			case 0x02:
+				return decode8_hr(fr, bits, dir);
+			case 0x07:
+				return decode8_data(fr, bits, dir);
+			case 0x13:
+				return decode8_oam(fr, bits, dir);
+			}
+		} else {
+			/* Downlink */
+			switch (cbits5 >> 2) {	/* Section 5.2.4.1.2 */
+			case 0:
+				return decode8_hr(fr, bits, dir);
+			case 1:
+				return decode8_data(fr, bits, dir);
+			case 2:
+				return decode8_oam(fr, bits, dir);
+			}
+		}
+	} else if (is_amr_low(bits)) {
+		return decode8_amr_low(fr, bits, dir);
+	} else if (is_amr_67(bits)) {
+		return decode8_amr_67(fr, bits, dir);
+	} else if (is_amr_74(bits)) {
+		return decode8_amr_74(fr, bits, dir);
+	}
+
+	return -EINVAL;
+}
+
+/* }@ */

-- 
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Gerrit-Project: libosmo-abis
Gerrit-Branch: master
Gerrit-Change-Id: I5cf42e6c445d9224be18503cebc7584b3beba08c
Gerrit-Change-Number: 18249
Gerrit-PatchSet: 11
Gerrit-Owner: laforge <laforge at osmocom.org>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge <laforge at osmocom.org>
Gerrit-MessageType: merged
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