bluez/audio/ipc.h

/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2004-2009  Marcel Holtmann <marcel@holtmann.org>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

/*
  Message sequence chart of streaming sequence for A2DP transport

  Audio daemon			User
				on snd_pcm_open
				<--BT_GET_CAPABILITIES_REQ

  BT_GET_CAPABILITIES_RSP-->

				on snd_pcm_hw_params
				<--BT_SETCONFIGURATION_REQ

  BT_SET_CONFIGURATION_RSP-->

				on snd_pcm_prepare
				<--BT_START_STREAM_REQ

  <Moves to streaming state>
  BT_START_STREAM_RSP-->

  BT_NEW_STREAM_IND -->

				<  streams data >
				..........

				on snd_pcm_drop/snd_pcm_drain

				<--BT_STOP_STREAM_REQ

  <Moves to open state>
  BT_STOP_STREAM_RSP-->

				on IPC close or appl crash
  <Moves to idle>

 */

#ifndef BT_AUDIOCLIENT_H
#define BT_AUDIOCLIENT_H

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>

#define BT_SUGGESTED_BUFFER_SIZE   512
#define BT_IPC_SOCKET_NAME "\0/org/bluez/audio"

/* Generic message header definition, except for RESPONSE messages */
typedef struct {
	uint8_t type;
	uint8_t name;
	uint16_t length;
} __attribute__ ((packed)) bt_audio_msg_header_t;

typedef struct {
	bt_audio_msg_header_t h;
	uint8_t posix_errno;
} __attribute__ ((packed)) bt_audio_error_t;

/* Message types */
#define BT_REQUEST			0
#define BT_RESPONSE			1
#define BT_INDICATION			2
#define BT_ERROR			3

/* Messages names */
#define BT_GET_CAPABILITIES		0
#define BT_OPEN				1
#define BT_SET_CONFIGURATION		2
#define BT_NEW_STREAM			3
#define BT_START_STREAM			4
#define BT_STOP_STREAM			5
#define BT_CONTROL			7

#define BT_CAPABILITIES_TRANSPORT_A2DP	0
#define BT_CAPABILITIES_TRANSPORT_SCO	1
#define BT_CAPABILITIES_TRANSPORT_ANY	2

#define BT_CAPABILITIES_ACCESS_MODE_READ	1
#define BT_CAPABILITIES_ACCESS_MODE_WRITE	2
#define BT_CAPABILITIES_ACCESS_MODE_READWRITE	3

#define BT_FLAG_AUTOCONNECT	1

struct bt_get_capabilities_req {
	bt_audio_msg_header_t	h;
	char			source[18];	/* Address of the local Device */
	char			destination[18];/* Address of the remote Device */
	char			object[128];	/* DBus object path */
	uint8_t			transport;	/* Requested transport */
	uint8_t			flags;		/* Requested flags */
	uint8_t			seid;		/* Requested capability configuration */
} __attribute__ ((packed));

/**
 * SBC Codec parameters as per A2DP profile 1.0 § 4.3
 */

/* A2DP seid are 6 bytes long so HSP/HFP are assigned to 7-8 bits */
#define BT_A2DP_SEID_RANGE			(1 << 6) - 1

#define BT_A2DP_CODEC_SBC			0x00
#define BT_A2DP_CODEC_MPEG12			0x01
#define BT_A2DP_CODEC_MPEG24			0x02
#define BT_A2DP_CODEC_ATRAC			0x03

#define BT_SBC_SAMPLING_FREQ_16000		(1 << 3)
#define BT_SBC_SAMPLING_FREQ_32000		(1 << 2)
#define BT_SBC_SAMPLING_FREQ_44100		(1 << 1)
#define BT_SBC_SAMPLING_FREQ_48000		1

#define BT_A2DP_CHANNEL_MODE_MONO		(1 << 3)
#define BT_A2DP_CHANNEL_MODE_DUAL_CHANNEL	(1 << 2)
#define BT_A2DP_CHANNEL_MODE_STEREO		(1 << 1)
#define BT_A2DP_CHANNEL_MODE_JOINT_STEREO	1

#define BT_A2DP_BLOCK_LENGTH_4			(1 << 3)
#define BT_A2DP_BLOCK_LENGTH_8			(1 << 2)
#define BT_A2DP_BLOCK_LENGTH_12			(1 << 1)
#define BT_A2DP_BLOCK_LENGTH_16			1

#define BT_A2DP_SUBBANDS_4			(1 << 1)
#define BT_A2DP_SUBBANDS_8			1

#define BT_A2DP_ALLOCATION_SNR			(1 << 1)
#define BT_A2DP_ALLOCATION_LOUDNESS		1

#define BT_MPEG_SAMPLING_FREQ_16000		(1 << 5)
#define BT_MPEG_SAMPLING_FREQ_22050		(1 << 4)
#define BT_MPEG_SAMPLING_FREQ_24000		(1 << 3)
#define BT_MPEG_SAMPLING_FREQ_32000		(1 << 2)
#define BT_MPEG_SAMPLING_FREQ_44100		(1 << 1)
#define BT_MPEG_SAMPLING_FREQ_48000		1

#define BT_MPEG_LAYER_1				(1 << 2)
#define BT_MPEG_LAYER_2				(1 << 1)
#define BT_MPEG_LAYER_3				1

#define BT_HFP_CODEC_PCM			0x00

#define BT_PCM_FLAG_NREC			0x01
#define BT_PCM_FLAG_PCM_ROUTING			0x02

typedef struct {
	uint8_t seid;
	uint8_t transport;
	uint8_t type;
	uint8_t length;
	uint8_t configured;
	uint8_t data[0];
} __attribute__ ((packed)) codec_capabilities_t;

typedef struct {
	codec_capabilities_t capability;
	uint8_t channel_mode;
	uint8_t frequency;
	uint8_t allocation_method;
	uint8_t subbands;
	uint8_t block_length;
	uint8_t min_bitpool;
	uint8_t max_bitpool;
} __attribute__ ((packed)) sbc_capabilities_t;

typedef struct {
	codec_capabilities_t capability;
	uint8_t channel_mode;
	uint8_t crc;
	uint8_t layer;
	uint8_t frequency;
	uint8_t mpf;
	uint16_t bitrate;
} __attribute__ ((packed)) mpeg_capabilities_t;

typedef struct {
	codec_capabilities_t capability;
	uint8_t flags;
	uint16_t sampling_rate;
} __attribute__ ((packed)) pcm_capabilities_t;

struct bt_get_capabilities_rsp {
	bt_audio_msg_header_t	h;
	char			source[18];	/* Address of the local Device */
	char			destination[18];/* Address of the remote Device */
	char			object[128];	/* DBus object path */
	uint8_t			data[0];	/* First codec_capabilities_t */
} __attribute__ ((packed));

struct bt_open_req {
	bt_audio_msg_header_t	h;
	char			source[18];	/* Address of the local Device */
	char			destination[18];/* Address of the remote Device */
	char			object[128];	/* DBus object path */
	uint8_t			seid;		/* Requested capability configuration to lock */
	uint8_t			lock;		/* Requested lock */
} __attribute__ ((packed));

struct bt_open_rsp {
	bt_audio_msg_header_t	h;
	char			source[18];	/* Address of the local Device */
	char			destination[18];/* Address of the remote Device */
	char			object[128];	/* DBus object path */
} __attribute__ ((packed));

struct bt_set_configuration_req {
	bt_audio_msg_header_t	h;
	codec_capabilities_t	codec;		/* Requested codec */
} __attribute__ ((packed));

struct bt_set_configuration_rsp {
	bt_audio_msg_header_t	h;
	uint16_t		link_mtu;	/* Max length that transport supports */
} __attribute__ ((packed));

#define BT_STREAM_ACCESS_READ		0
#define BT_STREAM_ACCESS_WRITE		1
#define BT_STREAM_ACCESS_READWRITE	2
struct bt_start_stream_req {
	bt_audio_msg_header_t	h;
} __attribute__ ((packed));

struct bt_start_stream_rsp {
	bt_audio_msg_header_t	h;
} __attribute__ ((packed));

/* This message is followed by one byte of data containing the stream data fd
   as ancilliary data */
struct bt_new_stream_ind {
	bt_audio_msg_header_t	h;
} __attribute__ ((packed));

struct bt_stop_stream_req {
	bt_audio_msg_header_t	h;
} __attribute__ ((packed));

struct bt_stop_stream_rsp {
	bt_audio_msg_header_t	h;
} __attribute__ ((packed));

struct bt_suspend_stream_ind {
	bt_audio_msg_header_t	h;
} __attribute__ ((packed));

struct bt_resume_stream_ind {
	bt_audio_msg_header_t	h;
} __attribute__ ((packed));

#define BT_CONTROL_KEY_POWER			0x40
#define BT_CONTROL_KEY_VOL_UP			0x41
#define BT_CONTROL_KEY_VOL_DOWN			0x42
#define BT_CONTROL_KEY_MUTE			0x43
#define BT_CONTROL_KEY_PLAY			0x44
#define BT_CONTROL_KEY_STOP			0x45
#define BT_CONTROL_KEY_PAUSE			0x46
#define BT_CONTROL_KEY_RECORD			0x47
#define BT_CONTROL_KEY_REWIND			0x48
#define BT_CONTROL_KEY_FAST_FORWARD		0x49
#define BT_CONTROL_KEY_EJECT			0x4A
#define BT_CONTROL_KEY_FORWARD			0x4B
#define BT_CONTROL_KEY_BACKWARD			0x4C

struct bt_control_req {
	bt_audio_msg_header_t	h;
	uint8_t			mode;		/* Control Mode */
	uint8_t			key;		/* Control Key */
} __attribute__ ((packed));

struct bt_control_rsp {
	bt_audio_msg_header_t	h;
	uint8_t			mode;		/* Control Mode */
	uint8_t			key;		/* Control Key */
} __attribute__ ((packed));

struct bt_control_ind {
	bt_audio_msg_header_t	h;
	uint8_t			mode;		/* Control Mode */
	uint8_t			key;		/* Control Key */
} __attribute__ ((packed));

/* Function declaration */

/* Opens a connection to the audio service: return a socket descriptor */
int bt_audio_service_open(void);

/* Closes a connection to the audio service */
int bt_audio_service_close(int sk);

/* Receives stream data file descriptor : must be called after a
BT_STREAMFD_IND message is returned */
int bt_audio_service_get_data_fd(int sk);

/* Human readable message type string */
const char *bt_audio_strtype(uint8_t type);

/* Human readable message name string */
const char *bt_audio_strname(uint8_t name);

#ifdef __cplusplus
}
#endif

#endif /* BT_AUDIOCLIENT_H */