ble_gatt_access_ctxt struct

Indicates the gatt operation being performed. This is equal to one of the following values: o BLE_GATT_ACCESS_OP_READ_CHR o BLE_GATT_ACCESS_OP_WRITE_CHR o BLE_GATT_ACCESS_OP_READ_DSC o BLE_GATT_ACCESS_OP_WRITE_DSC.

A container for the GATT access data. o For reads: The application populates this with the value of the characteristic or descriptor being read. o For writes: This is already populated with the value being written by the peer. If the application wishes to retain this mbuf for later use, the access callback must set this pointer to NULL to prevent the stack from freeing it.

An offset in case of BLE_ATT_OP_READ_BLOB_REQ. If the value is greater than zero it's an indication of a long attribute read.