GATT Server

GATT Server.

Modules

sl_bt_evt_gatt_server_attribute_value
Indicates that the value of an attribute in the local GATT database was changed by a remote GATT client.
 
sl_bt_evt_gatt_server_user_read_request
Indicates that a remote GATT client is attempting to read a value of an attribute from the local GATT database, where the attribute was defined in the GATT database XML file to have the type="user".
 
sl_bt_evt_gatt_server_user_write_request
Indicates that a remote GATT client is attempting to write a value of an attribute into the local GATT database, where the attribute was defined in the GATT database XML file to have the type="user".
 
sl_bt_evt_gatt_server_characteristic_status
Indicates either that a local Client Characteristic Configuration descriptor was changed by the remote GATT client, or that a confirmation from the remote GATT client was received upon a successful reception of the indication.
 
sl_bt_evt_gatt_server_execute_write_completed
Execute write completed event indicates that the execute write command from a remote GATT client has completed with the given result.
 

Enumerations

enum  gatt_server_characteristic_status_flag_t { gatt_server_client_config = 0x1, gatt_server_confirmation = 0x2 }
 Characteristic Status Flag.
 

Functions

sl_status_t sl_bt_gatt_server_set_capabilities (uint32_t caps, uint32_t reserved)
 
sl_status_t sl_bt_gatt_server_enable_capabilities (uint32_t caps)
 
sl_status_t sl_bt_gatt_server_disable_capabilities (uint32_t caps)
 
sl_status_t sl_bt_gatt_server_get_enabled_capabilities (uint32_t *caps)
 
sl_status_t sl_bt_gatt_server_set_max_mtu (uint16_t max_mtu, uint16_t *max_mtu_out)
 
sl_status_t sl_bt_gatt_server_get_mtu (uint8_t connection, uint16_t *mtu)
 
sl_status_t sl_bt_gatt_server_find_attribute (uint16_t start, size_t type_len, const uint8_t *type, uint16_t *attribute)
 
sl_status_t sl_bt_gatt_server_read_attribute_value (uint16_t attribute, uint16_t offset, size_t max_value_size, size_t *value_len, uint8_t *value)
 
sl_status_t sl_bt_gatt_server_read_attribute_type (uint16_t attribute, size_t max_type_size, size_t *type_len, uint8_t *type)
 
sl_status_t sl_bt_gatt_server_write_attribute_value (uint16_t attribute, uint16_t offset, size_t value_len, const uint8_t *value)
 
sl_status_t sl_bt_gatt_server_send_user_read_response (uint8_t connection, uint16_t characteristic, uint8_t att_errorcode, size_t value_len, const uint8_t *value, uint16_t *sent_len)
 
sl_status_t sl_bt_gatt_server_send_user_write_response (uint8_t connection, uint16_t characteristic, uint8_t att_errorcode)
 
sl_status_t sl_bt_gatt_server_send_characteristic_notification (uint8_t connection, uint16_t characteristic, size_t value_len, const uint8_t *value, uint16_t *sent_len)
 

Detailed Description

GATT Server.

These commands and events are used by the local GATT server to manage the local GATT database.

Enumeration Type Documentation

◆ gatt_server_characteristic_status_flag_t

enum gatt_server_characteristic_status_flag_t

Characteristic Status Flag.

Enumerator
gatt_server_client_config 

(0x1) Characteristic client configuration has been changed.

gatt_server_confirmation 

(0x2) Characteristic confirmation has been received.

Function Documentation

◆ sl_bt_gatt_server_set_capabilities()

sl_status_t sl_bt_gatt_server_set_capabilities ( uint32_t  caps,
uint32_t  reserved 
)

Reset capabilities that should be enabled by the GATT database. A service is visible to remote GATT clients if at least one of its capabilities is enabled. The same applies to a characteristic and its attributes. Capability identifiers and their corresponding bit flag values can be found in the auto-generated database header file. See UG118: Blue Gecko Bluetooth Profile Toolkit Developer's Guide for how to declare capabilities in the GATT database.

Changing the capabilities of a database effectively causes a database change (attributes being added or removed) from a remote GATT client point of view. If the database has a Generic Attribute service and Service Changed characteristic, the stack will monitor the local database change status and manage service changed indications for a GATT client that has enabled the indication configuration of the Service Changed characteristic.

Parameters
[in]capsBit flags of capabilities to reset. Value 0 sets the default database capabilities.
[in]reservedUse the value 0 on this reserved field. Do not use none-zero values because they are reserved for future use.
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_enable_capabilities()

sl_status_t sl_bt_gatt_server_enable_capabilities ( uint32_t  caps)

Enable additional capabilities in the local GATT database. Already enabled capabilities keep unchanged after this command. See sl_bt_gatt_server_set_capabilities for more information.

Parameters
[in]capsCapabilities to enable
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_disable_capabilities()

sl_status_t sl_bt_gatt_server_disable_capabilities ( uint32_t  caps)

Disable the given capabilities in the local GATT database. See sl_bt_gatt_server_set_capabilities for more information.

Parameters
[in]capsCapabilities to disable
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_get_enabled_capabilities()

sl_status_t sl_bt_gatt_server_get_enabled_capabilities ( uint32_t *  caps)

Get capabilities currently enabled in the local GATT database.

Parameters
[out]capsEnabled capabilities
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_set_max_mtu()

sl_status_t sl_bt_gatt_server_set_max_mtu ( uint16_t  max_mtu,
uint16_t *  max_mtu_out 
)

Set the maximum size of ATT Message Transfer Units (MTU). The functionality is the same as sl_bt_gatt_set_max_mtu and this setting applies to both GATT client and server. If the given value is too large according to the maximum BGAPI payload size, the system will select the maximum possible value as the maximum ATT_MTU. If the maximum ATT_MTU is larger than 23, the GATT client in the stack will automatically send an MTU exchange request after a Bluetooth connection was established.

Parameters
[in]max_mtu

Maximum size of Message Transfer Units (MTU) allowed

  • Range: 23 to 250

Default: 247

[out]max_mtu_outThe maximum ATT_MTU selected by the system if this command succeeded
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_get_mtu()

sl_status_t sl_bt_gatt_server_get_mtu ( uint8_t  connection,
uint16_t *  mtu 
)

Get the size of ATT Message Transfer Units (MTU) for a connection.

Parameters
[in]connectionConnection handle
[out]mtuThe maximum ATT_MTU used by the connection
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_find_attribute()

sl_status_t sl_bt_gatt_server_find_attribute ( uint16_t  start,
size_t  type_len,
const uint8_t *  type,
uint16_t *  attribute 
)

Find attributes of a certain type from a local GATT database. The type is usually given as a 16-bit or 128-bit UUID in little endian format.

Parameters
[in]startSearch start handle
[in]type_lenArray length
[in]typeThe attribute type UUID
[out]attributeAttribute handle
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_read_attribute_value()

sl_status_t sl_bt_gatt_server_read_attribute_value ( uint16_t  attribute,
uint16_t  offset,
size_t  max_value_size,
size_t *  value_len,
uint8_t *  value 
)

Read the value of an attribute from a local GATT database. Only (maximum BGAPI payload size - 3) amount of data can be read at once. The application can continue reading with increased offset value if it receives (maximum BGAPI payload size - 3) amount of data.

Parameters
[in]attributeAttribute handle
[in]offsetValue offset
[in]max_value_sizeSize of output buffer passed in value
[out]value_lenOn return, set to the length of output data written to value
[out]valueThe attribute value
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_read_attribute_type()

sl_status_t sl_bt_gatt_server_read_attribute_type ( uint16_t  attribute,
size_t  max_type_size,
size_t *  type_len,
uint8_t *  type 
)

Read the type of an attribute from a local GATT database. The type is a UUID, usually 16 or 128 bits long in little endian format.

Parameters
[in]attributeAttribute handle
[in]max_type_sizeSize of output buffer passed in type
[out]type_lenOn return, set to the length of output data written to type
[out]typeThe attribute type UUID
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_write_attribute_value()

sl_status_t sl_bt_gatt_server_write_attribute_value ( uint16_t  attribute,
uint16_t  offset,
size_t  value_len,
const uint8_t *  value 
)

Write the value of an attribute in the local GATT database. Writing the value of a characteristic of the local GATT database will not trigger notifications or indications to the remote GATT client if the characteristic has a property to indicate or notify and the client has enabled notification or indication. Notifications and indications are sent to the remote GATT client using sl_bt_gatt_server_send_characteristic_notification command.

Parameters
[in]attributeAttribute handle
[in]offsetValue offset
[in]value_lenArray length
[in]valueValue
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_send_user_read_response()

sl_status_t sl_bt_gatt_server_send_user_read_response ( uint8_t  connection,
uint16_t  characteristic,
uint8_t  att_errorcode,
size_t  value_len,
const uint8_t *  value,
uint16_t *  sent_len 
)

Send a response to a sl_bt_evt_gatt_server_user_read_request event. The response needs to be sent within 30 seconds, otherwise no more GATT transactions are allowed by the remote side. If attr_errorcode is set to 0, the characteristic value is sent to the remote GATT client in the standard way. Other attr_errorcode values will cause the local GATT server to send an attribute protocol error response instead of the actual data. At most ATT_MTU - 1 amount of data can be sent at one time. The client will continue reading by sending new read request with an increased offset value if it receives ATT_MTU - 1 amount of data.

Parameters
[in]connectionConnection handle
[in]characteristicGATT characteristic handle received in the sl_bt_evt_gatt_server_user_read_request event.
[in]att_errorcodeAttribute protocol error code
  • 0: No error
  • Non-zero: See Bluetooth specification, Host volume, Attribute Protocol, Error Codes table.
[in]value_lenArray length
[in]valueCharacteristic value to send to the GATT client. Ignored if att_errorcode is not 0.
[out]sent_lenThe length of data sent to the remote GATT client
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_send_user_write_response()

sl_status_t sl_bt_gatt_server_send_user_write_response ( uint8_t  connection,
uint16_t  characteristic,
uint8_t  att_errorcode 
)

Send a response to a sl_bt_evt_gatt_server_user_write_request event when parameter att_opcode in the event is gatt_write_request (see gatt_att_opcode). The response needs to be sent within 30 seconds, otherwise no more GATT transactions are allowed by the remote side. If attr_errorcode is set to 0, the ATT protocol's write response is sent to indicate to the remote GATT client that the write operation was processed successfully. Other values will cause the local GATT server to send an ATT protocol error response.

Parameters
[in]connectionConnection handle
[in]characteristicGATT characteristic handle received in the sl_bt_evt_gatt_server_user_write_request event
[in]att_errorcodeAttribute protocol error code
  • 0: No error
  • Non-zero: See Bluetooth specification, Host volume, Attribute Protocol, Error Codes table.
Returns
SL_STATUS_OK if successful. Error code otherwise.

◆ sl_bt_gatt_server_send_characteristic_notification()

sl_status_t sl_bt_gatt_server_send_characteristic_notification ( uint8_t  connection,
uint16_t  characteristic,
size_t  value_len,
const uint8_t *  value,
uint16_t *  sent_len 
)

Send notifications or indications to one or more remote GATT clients. At most ATT_MTU - 3 amount of data can be sent one time.

A notification or indication is sent only if the client has enabled it by setting the corresponding flag to the Client Characteristic Configuration descriptor. If the Client Characteristic Configuration descriptor supports both notifications and indications, the stack will always send a notification even when the client has enabled both.

A new indication to a GATT client can't be sent until an outstanding indication procedure with the same client has completed. The procedure is completed when a confirmation from the client is received. The confirmation is indicated by sl_bt_evt_gatt_server_characteristic_status.

Error bg_err_wrong_state is returned if the characteristic does not have the notification property, or if the client has not enabled the notification. The same applies to the indication property, and in addition, bg_err_wrong_state is returned if an indication procedure with the same client is outstanding. Always check the response for this command for errors before trying to send more data.

Parameters
[in]connectionA handle of the connection over which the notification or indication is sent. Values:
  • 0xff: Sends notification or indication to all connected devices.
  • Other: Connection handle
[in]characteristicCharacteristic handle
[in]value_lenArray length
[in]valueValue to be notified or indicated
[out]sent_lenThe length of data sent if only one connected device is the receiver; otherwise an unused value.
Returns
SL_STATUS_OK if successful. Error code otherwise.