GATT Server APIs

Data Structures
struct	bt_gatt_ccc_cfg
	GATT CCC configuration entry. More...
struct	bt_gatt_notify_params
struct	bt_gatt_indicate_params
	GATT Indicate Value parameters. More...

Macros
#define	BT_GATT_SERVICE_DEFINE(_name, ...)
	Statically define and register a service.
#define	BT_GATT_SERVICE_INSTANCE_DEFINE( _name, _instances, _instance_num, _attrs_def)
	Statically define service structure array.
#define	BT_GATT_SERVICE(_attrs)
	Service Structure Declaration Macro.
#define	BT_GATT_PRIMARY_SERVICE(_service)
	Primary Service Declaration Macro.
#define	BT_GATT_SECONDARY_SERVICE(_service)
	Secondary Service Declaration Macro.
#define	BT_GATT_INCLUDE_SERVICE(_service_incl)
	Include Service Declaration Macro.
#define	BT_GATT_CHRC_INIT(_uuid, _handle, _props)
#define	BT_GATT_CHARACTERISTIC(_uuid, _props, _perm, _read, _write, _user_data)
	Characteristic and Value Declaration Macro.
#define	BT_GATT_CCC_MAX   0
#define	BT_GATT_CCC_INITIALIZER(_changed, _write, _match)
	Initialize Client Characteristic Configuration Declaration Macro.
#define	BT_GATT_CCC_MANAGED(_ccc, _perm)
	Managed Client Characteristic Configuration Declaration Macro.
#define	BT_GATT_CCC(_changed, _perm)
	Client Characteristic Configuration Declaration Macro.
#define	BT_GATT_CEP(_value)
	Characteristic Extended Properties Declaration Macro.
#define	BT_GATT_CUD(_value, _perm)
	Characteristic User Format Descriptor Declaration Macro.
#define	BT_GATT_CPF(_value)
	Characteristic Presentation Format Descriptor Declaration Macro.
#define	BT_GATT_DESCRIPTOR(_uuid, _perm, _read, _write, _user_data)
	Descriptor Declaration Macro.
#define	BT_GATT_ATTRIBUTE(_uuid, _perm, _read, _write, _user_data)
	Attribute Declaration Macro.

Typedefs
typedef uint8_t(*	bt_gatt_attr_func_t) (const struct bt_gatt_attr *attr, uint16_t handle, void *user_data)
	Attribute iterator callback.
typedef void(*	bt_gatt_complete_func_t) (struct bt_conn *conn, void *user_data)
	Notification complete result callback.
typedef void(*	bt_gatt_indicate_func_t) (struct bt_conn *conn, struct bt_gatt_indicate_params *params, uint8_t err)
	Indication complete result callback.
typedef void(*	bt_gatt_indicate_params_destroy_t) (struct bt_gatt_indicate_params *params)

Enumerations
enum	{ BT_GATT_ITER_STOP = 0 , BT_GATT_ITER_CONTINUE }

Functions
static const char *	bt_gatt_err_to_str (int gatt_err)
	Converts a GATT error to string.
void	bt_gatt_cb_register (struct bt_gatt_cb *cb)
	Register GATT callbacks.
int	bt_gatt_authorization_cb_register (const struct bt_gatt_authorization_cb *cb)
	Register GATT authorization callbacks.
int	bt_gatt_service_register (struct bt_gatt_service *svc)
	Register GATT service.
int	bt_gatt_service_unregister (struct bt_gatt_service *svc)
	Unregister GATT service.
bool	bt_gatt_service_is_registered (const struct bt_gatt_service *svc)
	Check if GATT service is registered.
void	bt_gatt_foreach_attr_type (uint16_t start_handle, uint16_t end_handle, const struct bt_uuid *uuid, const void *attr_data, uint16_t num_matches, bt_gatt_attr_func_t func, void *user_data)
	Attribute iterator by type.
static void	bt_gatt_foreach_attr (uint16_t start_handle, uint16_t end_handle, bt_gatt_attr_func_t func, void *user_data)
	Attribute iterator.
struct bt_gatt_attr *	bt_gatt_attr_next (const struct bt_gatt_attr *attr)
	Iterate to the next attribute.
struct bt_gatt_attr *	bt_gatt_find_by_uuid (const struct bt_gatt_attr *attr, uint16_t attr_count, const struct bt_uuid *uuid)
	Find Attribute by UUID.
uint16_t	bt_gatt_attr_get_handle (const struct bt_gatt_attr *attr)
	Get Attribute handle.
uint16_t	bt_gatt_attr_value_handle (const struct bt_gatt_attr *attr)
	Get the handle of the characteristic value descriptor.
ssize_t	bt_gatt_attr_read (struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf, uint16_t buf_len, uint16_t offset, const void *value, uint16_t value_len)
	Generic Read Attribute value helper.
ssize_t	bt_gatt_attr_read_service (struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf, uint16_t len, uint16_t offset)
	Read Service Attribute helper.
ssize_t	bt_gatt_attr_read_included (struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf, uint16_t len, uint16_t offset)
	Read Include Attribute helper.
ssize_t	bt_gatt_attr_read_chrc (struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf, uint16_t len, uint16_t offset)
	Read Characteristic Attribute helper.
ssize_t	bt_gatt_attr_read_ccc (struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf, uint16_t len, uint16_t offset)
	Read Client Characteristic Configuration Attribute helper.
ssize_t	bt_gatt_attr_write_ccc (struct bt_conn *conn, const struct bt_gatt_attr *attr, const void *buf, uint16_t len, uint16_t offset, uint8_t flags)
	Write Client Characteristic Configuration Attribute helper.
ssize_t	bt_gatt_attr_read_cep (struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf, uint16_t len, uint16_t offset)
	Read Characteristic Extended Properties Attribute helper.
ssize_t	bt_gatt_attr_read_cud (struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf, uint16_t len, uint16_t offset)
	Read Characteristic User Description Descriptor Attribute helper.
ssize_t	bt_gatt_attr_read_cpf (struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf, uint16_t len, uint16_t offset)
	Read Characteristic Presentation format Descriptor Attribute helper.
int	bt_gatt_notify_cb (struct bt_conn *conn, struct bt_gatt_notify_params *params)
	Notify attribute value change.
int	bt_gatt_notify_multiple (struct bt_conn *conn, uint16_t num_params, struct bt_gatt_notify_params params[])
	Send multiple notifications in a single PDU.
static int	bt_gatt_notify (struct bt_conn *conn, const struct bt_gatt_attr *attr, const void *data, uint16_t len)
	Notify attribute value change.
static int	bt_gatt_notify_uuid (struct bt_conn *conn, const struct bt_uuid *uuid, const struct bt_gatt_attr *attr, const void *data, uint16_t len)
	Notify attribute value change by UUID.
int	bt_gatt_indicate (struct bt_conn *conn, struct bt_gatt_indicate_params *params)
	Indicate attribute value change.
bool	bt_gatt_is_subscribed (struct bt_conn *conn, const struct bt_gatt_attr *attr, uint16_t ccc_type)
	Check if connection have subscribed to attribute.
uint16_t	bt_gatt_get_mtu (struct bt_conn *conn)
	Get ATT MTU for a connection.
uint16_t	bt_gatt_get_uatt_mtu (struct bt_conn *conn)
	Get Unenhanced ATT (UATT) MTU for a connection.

Detailed Description

Macro Definition Documentation

BT_GATT_ATTRIBUTE

#define BT_GATT_ATTRIBUTE	(		_uuid,
			_perm,
			_read,
			_write,
			_user_data )

#include <zephyr/bluetooth/gatt.h>

Value:

{                                                                       \
        .uuid = _uuid,                                                  \
        .read = _read,                                                  \
        .write = _write,                                                \
        .user_data = _user_data,                                        \
        .handle = 0,                                                    \
        .perm = _perm,                                                  \
}

Attribute Declaration Macro.

Helper macro to declare an attribute.

Parameters

_uuid	Attribute uuid.
_perm	Attribute access permissions, a bitmap of bt_gatt_perm values.
_read	Attribute read callback (bt_gatt_attr_read_func_t).
_write	Attribute write callback (bt_gatt_attr_write_func_t).
_user_data	Attribute user data.

BT_GATT_CCC

#define BT_GATT_CCC	(		_changed,
			_perm )

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_CCC_MANAGED(((struct _bt_gatt_ccc[])                    \
                {BT_GATT_CCC_INITIALIZER(_changed, NULL, NULL)}), _perm)

Client Characteristic Configuration Declaration Macro.

Helper macro to declare a CCC attribute.

Parameters

_changed	Configuration changed callback.
_perm	CCC access permissions, a bitmap of bt_gatt_perm values.

BT_GATT_CCC_INITIALIZER

#define BT_GATT_CCC_INITIALIZER	(		_changed,
			_write,
			_match )

#include <zephyr/bluetooth/gatt.h>

Value:

        {                                            \
                .cfg = {},                           \
                .cfg_changed = _changed,             \
                .cfg_write = _write,                 \
                .cfg_match = _match,                 \
        }

Initialize Client Characteristic Configuration Declaration Macro.

Helper macro to initialize a Managed CCC attribute value.

Parameters

_changed	Configuration changed callback.
_write	Configuration write callback.
_match	Configuration match callback.

BT_GATT_CCC_MANAGED

#define BT_GATT_CCC_MANAGED	(		_ccc,
			_perm )

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_ATTRIBUTE(BT_UUID_GATT_CCC, _perm,                      \
                        bt_gatt_attr_read_ccc, bt_gatt_attr_write_ccc,  \
                        _ccc)

Managed Client Characteristic Configuration Declaration Macro.

Helper macro to declare a Managed CCC attribute.

Parameters

_ccc	CCC attribute user data, shall point to a _bt_gatt_ccc.
_perm	CCC access permissions, a bitmap of bt_gatt_perm values.

BT_GATT_CCC_MAX

#define BT_GATT_CCC_MAX   0

#include <zephyr/bluetooth/gatt.h>

BT_GATT_CEP

#define BT_GATT_CEP

(

_value

)

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_DESCRIPTOR(BT_UUID_GATT_CEP, BT_GATT_PERM_READ,         \
                          bt_gatt_attr_read_cep, NULL, (void *)_value)

Characteristic Extended Properties Declaration Macro.

Helper macro to declare a CEP attribute.

Parameters

_value

Pointer to a struct bt_gatt_cep.

BT_GATT_CHARACTERISTIC

#define BT_GATT_CHARACTERISTIC	(		_uuid,
			_props,
			_perm,
			_read,
			_write,
			_user_data )

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_ATTRIBUTE(BT_UUID_GATT_CHRC, BT_GATT_PERM_READ,                 \
                          bt_gatt_attr_read_chrc, NULL,                         \
                          ((struct bt_gatt_chrc[]) {                            \
                                BT_GATT_CHRC_INIT(_uuid, 0U, _props),           \
                                                   })),                         \
        BT_GATT_ATTRIBUTE(_uuid, _perm, _read, _write, _user_data)

Characteristic and Value Declaration Macro.

Helper macro to declare a characteristic attribute along with its attribute value.

Parameters

_uuid	Characteristic attribute uuid.
_props	Characteristic attribute properties, a bitmap of BT_GATT_CHRC_* macros.
_perm	Characteristic Attribute access permissions, a bitmap of bt_gatt_perm values.
_read	Characteristic Attribute read callback (bt_gatt_attr_read_func_t).
_write	Characteristic Attribute write callback (bt_gatt_attr_write_func_t).
_user_data	Characteristic Attribute user data.

BT_GATT_CHRC_INIT

#define BT_GATT_CHRC_INIT	(		_uuid,
			_handle,
			_props )

#include <zephyr/bluetooth/gatt.h>

Value:

{                                                 \
        .uuid = _uuid,                            \
        .value_handle = _handle,                  \
        .properties = _props,                     \
}

BT_GATT_CPF

#define BT_GATT_CPF

(

_value

)

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_DESCRIPTOR(BT_UUID_GATT_CPF, BT_GATT_PERM_READ,         \
                          bt_gatt_attr_read_cpf, NULL, (void *)_value)

Characteristic Presentation Format Descriptor Declaration Macro.

Helper macro to declare a CPF attribute.

Parameters

_value

Pointer to a struct bt_gatt_cpf.

BT_GATT_CUD

#define BT_GATT_CUD	(		_value,
			_perm )

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_DESCRIPTOR(BT_UUID_GATT_CUD, _perm, bt_gatt_attr_read_cud, \
                           NULL, (void *)_value)

Characteristic User Format Descriptor Declaration Macro.

Helper macro to declare a CUD attribute.

Parameters

_value	User description NULL-terminated C string.
_perm	Descriptor attribute access permissions, a bitmap of bt_gatt_perm values.

BT_GATT_DESCRIPTOR

#define BT_GATT_DESCRIPTOR	(		_uuid,
			_perm,
			_read,
			_write,
			_user_data )

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_ATTRIBUTE(_uuid, _perm, _read, _write, _user_data)

Descriptor Declaration Macro.

Helper macro to declare a descriptor attribute.

Parameters

_uuid	Descriptor attribute uuid.
_perm	Descriptor attribute access permissions, a bitmap of bt_gatt_perm values.
_read	Descriptor attribute read callback (bt_gatt_attr_read_func_t).
_write	Descriptor attribute write callback (bt_gatt_attr_write_func_t).
_user_data	Descriptor attribute user data.

BT_GATT_INCLUDE_SERVICE

#define BT_GATT_INCLUDE_SERVICE

(

_service_incl

)

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_ATTRIBUTE(BT_UUID_GATT_INCLUDE, BT_GATT_PERM_READ,      \
                          bt_gatt_attr_read_included, NULL, _service_incl)

Include Service Declaration Macro.

Helper macro to declare database internal include service attribute.

Parameters

_service_incl

the first service attribute of service to include

BT_GATT_PRIMARY_SERVICE

#define BT_GATT_PRIMARY_SERVICE

(

_service

)

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_ATTRIBUTE(BT_UUID_GATT_PRIMARY, BT_GATT_PERM_READ,      \
                         bt_gatt_attr_read_service, NULL, (void *)_service)

Primary Service Declaration Macro.

Helper macro to declare a primary service attribute.

Parameters

_service

Service attribute value.

BT_GATT_SECONDARY_SERVICE

#define BT_GATT_SECONDARY_SERVICE

(

_service

)

#include <zephyr/bluetooth/gatt.h>

Value:

        BT_GATT_ATTRIBUTE(BT_UUID_GATT_SECONDARY, BT_GATT_PERM_READ,    \
                         bt_gatt_attr_read_service, NULL, (void *)_service)

Secondary Service Declaration Macro.

Helper macro to declare a secondary service attribute.

Note

A secondary service is only intended to be included from a primary service or another secondary service or other higher layer specification.

Parameters

_service

Service attribute value.

BT_GATT_SERVICE

#define BT_GATT_SERVICE

(

_attrs

)

#include <zephyr/bluetooth/gatt.h>

Value:

{                                                                       \
        .attrs = _attrs,                                                \
        .attr_count = ARRAY_SIZE(_attrs),                               \
}

Service Structure Declaration Macro.

Helper macro to declare a service structure.

Parameters

_attrs

Service attributes.

BT_GATT_SERVICE_DEFINE

#define BT_GATT_SERVICE_DEFINE	(		_name,
			... )

#include <zephyr/bluetooth/gatt.h>

Value:

        const struct bt_gatt_attr attr_##_name[] = { __VA_ARGS__ };     \
        const STRUCT_SECTION_ITERABLE(bt_gatt_service_static, _name) =  \
                                        BT_GATT_SERVICE(attr_##_name)

Statically define and register a service.

Helper macro to statically define and register a service.

Parameters

_name

Service name.

BT_GATT_SERVICE_INSTANCE_DEFINE

#define BT_GATT_SERVICE_INSTANCE_DEFINE	(		_name,
			_instances,
			_instance_num,
			_attrs_def )

#include <zephyr/bluetooth/gatt.h>

Value:

        BUILD_ASSERT(ARRAY_SIZE(_instances) == _instance_num,            \
                "The number of array elements does not match its size"); \
        LISTIFY(_instance_num, _BT_GATT_ATTRS_ARRAY_DEFINE, (;),         \
                _instances, _attrs_def);                                 \
        static struct bt_gatt_service _name[] = {                        \
                LISTIFY(_instance_num, _BT_GATT_SERVICE_ARRAY_ITEM, (,)) \
        }

Statically define service structure array.

Helper macro to statically define service structure array. Each element of the array is linked to the service attribute array which is also defined in this scope using _attrs_def macro.

Parameters

_name	Name of service structure array.
_instances	Array of instances to pass as user context to the attribute callbacks.
_instance_num	Number of elements in instance array.
_attrs_def	Macro provided by the user that defines attribute array for the service. This macro should accept single parameter which is the instance context.

Typedef Documentation

bt_gatt_attr_func_t

typedef uint8_t(* bt_gatt_attr_func_t) (const struct bt_gatt_attr *attr, uint16_t handle, void *user_data)

#include <zephyr/bluetooth/gatt.h>

Attribute iterator callback.

Parameters

attr	Attribute found.
handle	Attribute handle found.
user_data	Data given.

Returns

BT_GATT_ITER_CONTINUE if should continue to the next attribute.

BT_GATT_ITER_STOP to stop.

bt_gatt_complete_func_t

typedef void(* bt_gatt_complete_func_t) (struct bt_conn *conn, void *user_data)

#include <zephyr/bluetooth/gatt.h>

Notification complete result callback.

Parameters

conn	Connection object.
user_data	Data passed in by the user.

bt_gatt_indicate_func_t

typedef void(* bt_gatt_indicate_func_t) (struct bt_conn *conn, struct bt_gatt_indicate_params *params, uint8_t err)

#include <zephyr/bluetooth/gatt.h>

Indication complete result callback.

Parameters

conn	Connection object.
params	Indication params object.
err	ATT error code

bt_gatt_indicate_params_destroy_t

typedef void(* bt_gatt_indicate_params_destroy_t) (struct bt_gatt_indicate_params *params)

#include <zephyr/bluetooth/gatt.h>

Enumeration Type Documentation

anonymous enum

anonymous enum

#include <zephyr/bluetooth/gatt.h>

Enumerator
BT_GATT_ITER_STOP
BT_GATT_ITER_CONTINUE

Function Documentation

bt_gatt_attr_get_handle()

uint16_t bt_gatt_attr_get_handle

(

const struct bt_gatt_attr *

attr

)

#include <zephyr/bluetooth/gatt.h>

Get Attribute handle.

Parameters

attr	An attribute object currently registered in the local ATT server.

Returns

Handle of the corresponding attribute or zero if the attribute could not be found.

bt_gatt_attr_next()

struct bt_gatt_attr * bt_gatt_attr_next

(

const struct bt_gatt_attr *

attr

)

#include <zephyr/bluetooth/gatt.h>

Iterate to the next attribute.

Iterate to the next attribute following a given attribute.

Parameters

attr	Current Attribute.

Returns

The next attribute or NULL if it cannot be found.

bt_gatt_attr_read()

ssize_t bt_gatt_attr_read	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		void *	buf,
		uint16_t	buf_len,
		uint16_t	offset,
		const void *	value,
		uint16_t	value_len )

#include <zephyr/bluetooth/gatt.h>

Generic Read Attribute value helper.

Read attribute value from local database storing the result into buffer.

Parameters

conn	Connection object.
attr	Attribute to read.
buf	Buffer to store the value.
buf_len	Buffer length.
offset	Start offset.
value	Attribute value.
value_len	Length of the attribute value.

Returns

number of bytes read in case of success or negative values in case of error.

bt_gatt_attr_read_ccc()

ssize_t bt_gatt_attr_read_ccc	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		void *	buf,
		uint16_t	len,
		uint16_t	offset )

#include <zephyr/bluetooth/gatt.h>

Read Client Characteristic Configuration Attribute helper.

Read CCC attribute value from local database storing the result into buffer after encoding it.

Note

Only use this with attributes which user_data is a _bt_gatt_ccc.

Parameters

conn	Connection object.
attr	Attribute to read.
buf	Buffer to store the value read.
len	Buffer length.
offset	Start offset.

Returns

number of bytes read in case of success or negative values in case of error.

bt_gatt_attr_read_cep()

ssize_t bt_gatt_attr_read_cep	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		void *	buf,
		uint16_t	len,
		uint16_t	offset )

#include <zephyr/bluetooth/gatt.h>

Read Characteristic Extended Properties Attribute helper.

Read CEP attribute value from local database storing the result into buffer after encoding it.

Note

Only use this with attributes which user_data is a bt_gatt_cep.

Parameters

conn	Connection object
attr	Attribute to read
buf	Buffer to store the value read
len	Buffer length
offset	Start offset

Returns

number of bytes read in case of success or negative values in case of error.

bt_gatt_attr_read_chrc()

ssize_t bt_gatt_attr_read_chrc	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		void *	buf,
		uint16_t	len,
		uint16_t	offset )

#include <zephyr/bluetooth/gatt.h>

Read Characteristic Attribute helper.

Read characteristic attribute value from local database storing the result into buffer after encoding it.

Note

Only use this with attributes which user_data is a bt_gatt_chrc.

Parameters

conn	Connection object.
attr	Attribute to read.
buf	Buffer to store the value read.
len	Buffer length.
offset	Start offset.

Returns

number of bytes read in case of success or negative values in case of error.

bt_gatt_attr_read_cpf()

ssize_t bt_gatt_attr_read_cpf	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		void *	buf,
		uint16_t	len,
		uint16_t	offset )

#include <zephyr/bluetooth/gatt.h>

Read Characteristic Presentation format Descriptor Attribute helper.

Read CPF attribute value from local database storing the result into buffer after encoding it.

Note

Only use this with attributes which user_data is a bt_gatt_pf.

Parameters

conn	Connection object
attr	Attribute to read
buf	Buffer to store the value read
len	Buffer length
offset	Start offset

Returns

number of bytes read in case of success or negative values in case of error.

bt_gatt_attr_read_cud()

ssize_t bt_gatt_attr_read_cud	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		void *	buf,
		uint16_t	len,
		uint16_t	offset )

#include <zephyr/bluetooth/gatt.h>

Read Characteristic User Description Descriptor Attribute helper.

Read CUD attribute value from local database storing the result into buffer after encoding it.

Note

Only use this with attributes which user_data is a NULL-terminated C string.

Parameters

conn	Connection object
attr	Attribute to read
buf	Buffer to store the value read
len	Buffer length
offset	Start offset

Returns

number of bytes read in case of success or negative values in case of error.

bt_gatt_attr_read_included()

ssize_t bt_gatt_attr_read_included	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		void *	buf,
		uint16_t	len,
		uint16_t	offset )

#include <zephyr/bluetooth/gatt.h>

Read Include Attribute helper.

Read include service attribute value from local database storing the result into buffer after encoding it.

Note

Only use this with attributes which user_data is a bt_gatt_include.

Parameters

conn	Connection object.
attr	Attribute to read.
buf	Buffer to store the value read.
len	Buffer length.
offset	Start offset.

Returns

number of bytes read in case of success or negative values in case of error.

bt_gatt_attr_read_service()

ssize_t bt_gatt_attr_read_service	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		void *	buf,
		uint16_t	len,
		uint16_t	offset )

#include <zephyr/bluetooth/gatt.h>

Read Service Attribute helper.

Read service attribute value from local database storing the result into buffer after encoding it.

Note

Only use this with attributes which user_data is a bt_uuid.

Parameters

conn	Connection object.
attr	Attribute to read.
buf	Buffer to store the value read.
len	Buffer length.
offset	Start offset.

Returns

number of bytes read in case of success or negative values in case of error.

bt_gatt_attr_value_handle()

uint16_t bt_gatt_attr_value_handle

(

const struct bt_gatt_attr *

attr

)

#include <zephyr/bluetooth/gatt.h>

Get the handle of the characteristic value descriptor.

Parameters

attr	A Characteristic Attribute.

Note

The user_data of the attribute must of type bt_gatt_chrc.

Returns

the handle of the corresponding Characteristic Value. The value will be zero (the invalid handle) if attr was not a characteristic attribute.

bt_gatt_attr_write_ccc()

ssize_t bt_gatt_attr_write_ccc	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		const void *	buf,
		uint16_t	len,
		uint16_t	offset,
		uint8_t	flags )

#include <zephyr/bluetooth/gatt.h>

Write Client Characteristic Configuration Attribute helper.

Write value in the buffer into CCC attribute.

Note

Only use this with attributes which user_data is a _bt_gatt_ccc.

Parameters

conn	Connection object.
attr	Attribute to read.
buf	Buffer to store the value read.
len	Buffer length.
offset	Start offset.
flags	Write flags.

Returns

number of bytes written in case of success or negative values in case of error.

bt_gatt_authorization_cb_register()

int bt_gatt_authorization_cb_register

(

const struct bt_gatt_authorization_cb *

cb

)

#include <zephyr/bluetooth/gatt.h>

Register GATT authorization callbacks.

Register callbacks to perform application-specific authorization of GATT operations on all registered GATT attributes. The callback structure must remain valid throughout the entire duration of the Bluetooth subsys activity.

The CONFIG_BT_GATT_AUTHORIZATION_CUSTOM Kconfig must be enabled to make this API functional.

This API allows the user to register only one callback structure concurrently. Passing NULL unregisters the previous set of callbacks and makes it possible to register a new one.

Parameters

cb	Callback struct.

Returns

Zero on success or negative error code otherwise

bt_gatt_cb_register()

void bt_gatt_cb_register

(

struct bt_gatt_cb *

cb

)

#include <zephyr/bluetooth/gatt.h>

Register GATT callbacks.

Register callbacks to monitor the state of GATT. The callback struct must remain valid for the remainder of the program.

Parameters

cb	Callback struct.

bt_gatt_err_to_str()

static const char * bt_gatt_err_to_str ( int gatt_err )

inlinestatic

#include <zephyr/bluetooth/gatt.h>

Converts a GATT error to string.

The GATT errors are created with BT_GATT_ERR.

The error codes are described in the Bluetooth Core specification, Vol 3, Part F, Section 3.4.1.1.

The ATT and GATT documentation found in Vol 4, Part F and Part G describe when the different error codes are used.

See also the defined BT_ATT_ERR_* macros.

Returns

The string representation of the GATT error code. If CONFIG_BT_ATT_ERR_TO_STR is not enabled, this just returns the empty string.

bt_gatt_find_by_uuid()

struct bt_gatt_attr * bt_gatt_find_by_uuid	(	const struct bt_gatt_attr *	attr,
		uint16_t	attr_count,
		const struct bt_uuid *	uuid )

#include <zephyr/bluetooth/gatt.h>

Find Attribute by UUID.

Find the attribute with the matching UUID. To limit the search to a service set the attr to the service attributes and the attr_count to the service attribute count .

Parameters

attr	Pointer to an attribute that serves as the starting point for the search of a match for the UUID. Passing NULL will search the entire range.
attr_count	The number of attributes from the starting point to search for a match for the UUID. Set to 0 to search until the end.
uuid	UUID to match.

bt_gatt_foreach_attr()

static void bt_gatt_foreach_attr ( uint16_t start_handle, uint16_t end_handle, bt_gatt_attr_func_t func, void * user_data )

inlinestatic

#include <zephyr/bluetooth/gatt.h>

Attribute iterator.

Iterate attributes in the given range.

Parameters

start_handle	Start handle.
end_handle	End handle.
func	Callback function.
user_data	Data to pass to the callback.

bt_gatt_foreach_attr_type()

void bt_gatt_foreach_attr_type	(	uint16_t	start_handle,
		uint16_t	end_handle,
		const struct bt_uuid *	uuid,
		const void *	attr_data,
		uint16_t	num_matches,
		bt_gatt_attr_func_t	func,
		void *	user_data )

#include <zephyr/bluetooth/gatt.h>

Attribute iterator by type.

Iterate attributes in the given range matching given UUID and/or data.

Parameters

start_handle	Start handle.
end_handle	End handle.
uuid	UUID to match, passing NULL skips UUID matching.
attr_data	Attribute data to match, passing NULL skips data matching.
num_matches	Number matches, passing 0 makes it unlimited.
func	Callback function.
user_data	Data to pass to the callback.

bt_gatt_get_mtu()

uint16_t bt_gatt_get_mtu

(

struct bt_conn *

conn

)

#include <zephyr/bluetooth/gatt.h>

Get ATT MTU for a connection.

Get negotiated ATT connection MTU, note that this does not equal the largest amount of attribute data that can be transferred within a single packet.

Parameters

conn	Connection object.

Returns

MTU in bytes

bt_gatt_get_uatt_mtu()

uint16_t bt_gatt_get_uatt_mtu

(

struct bt_conn *

conn

)

#include <zephyr/bluetooth/gatt.h>

Get Unenhanced ATT (UATT) MTU for a connection.

Get UATT connection MTU.

The ATT_MTU defines the largest size of an ATT PDU, encompassing the ATT opcode, additional fields, and any attribute value payload. Consequently, the maximum size of a value payload is less and varies based on the type of ATT PDU. For example, in an ATT_HANDLE_VALUE_NTF PDU, the Attribute Value field can contain up to ATT_MTU - 3 octets (size of opcode and handle).

Parameters

conn	Connection object.

Returns

0 if conn does not have an UATT ATT_MTU (e.g: disconnected).

Current UATT ATT_MTU.

bt_gatt_indicate()

int bt_gatt_indicate	(	struct bt_conn *	conn,
		struct bt_gatt_indicate_params *	params )

#include <zephyr/bluetooth/gatt.h>

Indicate attribute value change.

Send an indication of attribute value change. if connection is NULL indicate all peer that have notification enabled via CCC otherwise do a direct indication only the given connection.

The attribute object on the parameters can be the so called Characteristic Declaration, which is usually declared with BT_GATT_CHARACTERISTIC followed by BT_GATT_CCC, or the Characteristic Value Declaration which is automatically created after the Characteristic Declaration when using BT_GATT_CHARACTERISTIC.

Alternatively it is possible to indicate by UUID by setting it on the parameters, when using this method the attribute if provided is used as the start range when looking up for possible matches.

Note

This procedure is asynchronous therefore the parameters need to remains valid while it is active. The procedure is active until the destroy callback is run.

Parameters

conn	Connection object.
params	Indicate parameters.

Returns

0 in case of success or negative value in case of error.

bt_gatt_is_subscribed()

bool bt_gatt_is_subscribed	(	struct bt_conn *	conn,
		const struct bt_gatt_attr *	attr,
		uint16_t	ccc_type )

#include <zephyr/bluetooth/gatt.h>

Check if connection have subscribed to attribute.

Check if connection has subscribed to attribute value change.

The attribute object can be the so called Characteristic Declaration, which is usually declared with BT_GATT_CHARACTERISTIC followed by BT_GATT_CCC, or the Characteristic Value Declaration which is automatically created after the Characteristic Declaration when using BT_GATT_CHARACTERISTIC, or the Client Characteristic Configuration Descriptor (CCCD) which is created by BT_GATT_CCC.

Parameters

conn	Connection object.
attr	Attribute object.
ccc_type	The subscription type, BT_GATT_CCC_NOTIFY and/or BT_GATT_CCC_INDICATE.

Returns

true if the attribute object has been subscribed.

bt_gatt_notify()

static int bt_gatt_notify ( struct bt_conn * conn, const struct bt_gatt_attr * attr, const void * data, uint16_t len )

inlinestatic

#include <zephyr/bluetooth/gatt.h>

Notify attribute value change.

Send notification of attribute value change, if connection is NULL notify all peer that have notification enabled via CCC otherwise do a direct notification only the given connection.

The attribute object on the parameters can be the so called Characteristic Declaration, which is usually declared with BT_GATT_CHARACTERISTIC followed by BT_GATT_CCC, or the Characteristic Value Declaration which is automatically created after the Characteristic Declaration when using BT_GATT_CHARACTERISTIC.

Parameters

conn	Connection object.
attr	Characteristic or Characteristic Value attribute.
data	Pointer to Attribute data.
len	Attribute value length.

Returns

0 in case of success or negative value in case of error.

bt_gatt_notify_cb()

int bt_gatt_notify_cb	(	struct bt_conn *	conn,
		struct bt_gatt_notify_params *	params )

#include <zephyr/bluetooth/gatt.h>

Notify attribute value change.

This function works in the same way as bt_gatt_notify. With the addition that after sending the notification the callback function will be called.

The callback is run from System Workqueue context. When called from the System Workqueue context this API will not wait for resources for the callback but instead return an error. The number of pending callbacks can be increased with the CONFIG_BT_CONN_TX_MAX option.

Alternatively it is possible to notify by UUID by setting it on the parameters, when using this method the attribute if provided is used as the start range when looking up for possible matches.

Parameters

conn	Connection object.
params	Notification parameters.

Returns

0 in case of success or negative value in case of error.

bt_gatt_notify_multiple()

int bt_gatt_notify_multiple	(	struct bt_conn *	conn,
		uint16_t	num_params,
		struct bt_gatt_notify_params	params[] )

#include <zephyr/bluetooth/gatt.h>

Send multiple notifications in a single PDU.

The GATT Server will send a single ATT_MULTIPLE_HANDLE_VALUE_NTF PDU containing all the notifications passed to this API.

All params must have the same func and user_data (due to implementation limitation). But func(user_data) will be invoked for each parameter.

As this API may block to wait for Bluetooth Host resources, it is not recommended to call it from a cooperative thread or a Bluetooth callback.

The peer's GATT Client must write to this device's Client Supported Features attribute and set the bit for Multiple Handle Value Notifications before this API can be used.

Only use this API to force the use of the ATT_MULTIPLE_HANDLE_VALUE_NTF PDU. For standard applications, bt_gatt_notify_cb is preferred, as it will use this PDU if supported and automatically fallback to ATT_HANDLE_VALUE_NTF when not supported by the peer.

This API has an additional limitation: it only accepts valid attribute references and not UUIDs like bt_gatt_notify and bt_gatt_notify_cb.

Parameters

conn	Target client. Notifying all connected clients by passing NULL is not yet supported, please use bt_gatt_notify instead.
num_params	Element count of params array. Has to be greater than 1.
params	Array of notification parameters. It is okay to free this after calling this function.

Return values

0	Success. The PDU is queued for sending.
-EINVAL	One of the attribute handles is invalid. Only one parameter was passed. This API expects 2 or more. Not all func were equal or not all user_data were equal. One of the characteristics is not notifiable. An UUID was passed in one of the parameters.
-ERANGE	The notifications cannot all fit in a single ATT_MULTIPLE_HANDLE_VALUE_NTF. They exceed the MTU of all open ATT bearers.
-EPERM	The connection has a lower security level than required by one of the attributes.
-EOPNOTSUPP	The peer hasn't yet communicated that it supports this PDU type.

bt_gatt_notify_uuid()

static int bt_gatt_notify_uuid ( struct bt_conn * conn, const struct bt_uuid * uuid, const struct bt_gatt_attr * attr, const void * data, uint16_t len )

inlinestatic

#include <zephyr/bluetooth/gatt.h>

Notify attribute value change by UUID.

Send notification of attribute value change, if connection is NULL notify all peer that have notification enabled via CCC otherwise do a direct notification only on the given connection.

The attribute object is the starting point for the search of the UUID.

Parameters

conn	Connection object.
uuid	The UUID. If the server contains multiple services with the same UUID, then the first occurrence, starting from the attr given, is used.
attr	Pointer to an attribute that serves as the starting point for the search of a match for the UUID.
data	Pointer to Attribute data.
len	Attribute value length.

Returns

0 in case of success or negative value in case of error.

bt_gatt_service_is_registered()

bool bt_gatt_service_is_registered

(

const struct bt_gatt_service *

svc

)

#include <zephyr/bluetooth/gatt.h>

Check if GATT service is registered.

Parameters

svc	Service to be checked.

Returns

true if registered or false if not register.

bt_gatt_service_register()

int bt_gatt_service_register

(

struct bt_gatt_service *

svc

)

#include <zephyr/bluetooth/gatt.h>

Register GATT service.

Register GATT service. Applications can make use of macros such as BT_GATT_PRIMARY_SERVICE, BT_GATT_CHARACTERISTIC, BT_GATT_DESCRIPTOR, etc.

When using CONFIG_BT_SETTINGS then all services that should have bond configuration loaded, i.e. CCC values, must be registered before calling settings_load.

When using CONFIG_BT_GATT_CACHING and CONFIG_BT_SETTINGS then all services that should be included in the GATT Database Hash calculation should be added before calling settings_load. All services registered after settings_load will trigger a new database hash calculation and a new hash stored.

There are two situations where this function can be called: either before bt_init() has been called, or after settings_load() has been called. Registering a service in the middle is not supported and will return an error.

Parameters

svc	Service containing the available attributes

Returns

0 in case of success or negative value in case of error.

-EAGAIN if bt_init() has been called but settings_load() hasn't yet.

bt_gatt_service_unregister()

int bt_gatt_service_unregister

(

struct bt_gatt_service *

svc

)

#include <zephyr/bluetooth/gatt.h>

Unregister GATT service.

Parameters

svc	Service to be unregistered.

Returns

0 in case of success or negative value in case of error.