Attribute Protocol (ATT)

API Reference

group bt_att

Attribute Protocol (ATT)

Defines

BT_ATT_ERR_SUCCESS: The ATT operation was successful.

BT_ATT_ERR_INVALID_HANDLE: The attribute handle given was not valid on the server.

BT_ATT_ERR_READ_NOT_PERMITTED: The attribute cannot be read.

BT_ATT_ERR_WRITE_NOT_PERMITTED: The attribute cannot be written.

BT_ATT_ERR_INVALID_PDU: The attribute PDU was invalid.

BT_ATT_ERR_AUTHENTICATION: The attribute requires authentication before it can be read or written.

BT_ATT_ERR_NOT_SUPPORTED: The ATT Server does not support the request received from the client.

BT_ATT_ERR_INVALID_OFFSET: Offset specified was past the end of the attribute.

BT_ATT_ERR_AUTHORIZATION: The attribute requires authorization before it can be read or written.

BT_ATT_ERR_PREPARE_QUEUE_FULL: Too many prepare writes have been queued.

BT_ATT_ERR_ATTRIBUTE_NOT_FOUND: No attribute found within the given attribute handle range.

BT_ATT_ERR_ATTRIBUTE_NOT_LONG: The attribute cannot be read using the ATT_READ_BLOB_REQ PDU.

BT_ATT_ERR_ENCRYPTION_KEY_SIZE: The Encryption Key Size used for encrypting this link is too short.

BT_ATT_ERR_INVALID_ATTRIBUTE_LEN: The attribute value length is invalid for the operation.

BT_ATT_ERR_UNLIKELY

The attribute request that was requested has encountered an error that was unlikely.

The attribute request could therefore not be completed as requested

BT_ATT_ERR_INSUFFICIENT_ENCRYPTION: The attribute requires encryption before it can be read or written.

BT_ATT_ERR_UNSUPPORTED_GROUP_TYPE

The attribute type is not a supported grouping attribute.

The attribute type is not a supported grouping attribute as defined by a higher layer specification.

BT_ATT_ERR_INSUFFICIENT_RESOURCES: Insufficient Resources to complete the request.

BT_ATT_ERR_DB_OUT_OF_SYNC: The server requests the client to rediscover the database.

BT_ATT_ERR_VALUE_NOT_ALLOWED: The attribute parameter value was not allowed.

BT_ATT_ERR_WRITE_REQ_REJECTED: Write Request Rejected.

BT_ATT_ERR_CCC_IMPROPER_CONF: Client Characteristic Configuration Descriptor Improperly Configured.

BT_ATT_ERR_PROCEDURE_IN_PROGRESS: Procedure Already in Progress.

BT_ATT_ERR_OUT_OF_RANGE: Out of Range.

BT_ATT_MAX_ATTRIBUTE_LEN

BT_ATT_FIRST_ATTRIBUTE_HANDLE

BT_ATT_FIRST_ATTTRIBUTE_HANDLE

BT_ATT_LAST_ATTRIBUTE_HANDLE

BT_ATT_LAST_ATTTRIBUTE_HANDLE

Enums

enum bt_att_chan_opt

ATT channel option bit field values.

Note

BT_ATT_CHAN_OPT_UNENHANCED_ONLY and BT_ATT_CHAN_OPT_ENHANCED_ONLY are mutually exclusive and both bits may not be set.

Values:

enumerator BT_ATT_CHAN_OPT_NONE = 0x0: Both Enhanced and Unenhanced channels can be used

enumerator BT_ATT_CHAN_OPT_UNENHANCED_ONLY = BIT(0): Only Unenhanced channels will be used

enumerator BT_ATT_CHAN_OPT_ENHANCED_ONLY = BIT(1): Only Enhanced channels will be used

Functions

int bt_eatt_connect(struct bt_conn *conn, size_t num_channels)

Connect Enhanced ATT channels.

Sends a series of Credit Based Connection Requests to connect num_channels Enhanced ATT channels. The peer may have limited resources and fewer channels may be created.

Parameters:

conn – The connection to send the request on
num_channels – The number of Enhanced ATT beares to request. Must be in the range 1 - CONFIG_BT_EATT_MAX , inclusive.

Return values:

-EINVAL – if num_channels is not in the allowed range or conn is NULL.
-ENOMEM – if less than num_channels are allocated.
0 – in case of success

Returns:

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

size_t bt_eatt_count(struct bt_conn *conn)

Get number of EATT channels connected.

Parameters:

conn – The connection to get the number of EATT channels for.

Returns:

The number of EATT channels connected. Returns 0 if conn is NULL or not connected.