I am trying to implement a DTLS handshake between two BLE devices. For this, I wanted to use the L2CAP channel of the BLE to communicate with the messages coming from the DTLS. Basically, I want to open a DTLS tunnel with the help of L2CAP from the BLE stack. I am using the mbedTLS library for this. From the documentation of MbedTLS (https://tls.mbed.org/kb/how-to/how-do-i-port-mbed-tls-to-a-new-environment-OS), I understood that I need to set the mbed_tls_ssl_set_bio() function which has the read and write call back functions that communicates with the BLE top layers(L2CAP). I am using the dialog's DA14695 dongles for the implementation. I am not very sure about the read and write call back functions that needs to be written to communicate with the L2CAP channel of the BLE. Somebody experienced with opening a TLS/DTLS tunnel with the BLE top layers can help.
Thanks in advance