We received some pcap files from a customer which contained protocol
traces in a proprietary format (generated by unknown software/tools).
The format uses DLT_USER=162 with some proprietary header that describes
the next-layer protocol (like SGsAP, RANAP, TCAP, MTP3) and various
other bits we have no idea about.
Let's try to figure out where the next-layer payload is and pass that
to existing wireshark dissectors.