I'm using WireShark on Ubuntu 20.04.1 LTS. I listen to bluetooth0 interface while transferring a file from my laptop to my smartphone over Bluetooth(using Blueman). Without any transfer, I get packets for protocols: HCI_EVT and HCI_CMD to obtain Tx Power Level, RSSI, and Link Quality which makes sense.
When I transfer a file, I get additionally, L2CAP packets.
My goal is to filter only packets with fragmentation/packet/any loss/re-transmission error. I'm not perfectly familiar with the Bluetooth protocol, I have tried several filters from here: https://www.wireshark.org/docs/dfref/b/btl2cap.html
Any knowledge regarding the possibility to filter packets with fragmentation/packet/any loss/re-transmission error would really help.