How to dissect 5G RRC L3 messsages from L1 packets Tx_Data.request (FAPI logs) in wireshark using a custom dissector DLL?
I am working at the PHY (L1) layer in a 5G NR stack implementation. At this layer, I receive Tx_Data.request messages from MAC (as per Small Cell Forum FAPI interface). These contain transport blocks that L1 needs to transmit.
My goal is to:
Export these Tx_Data.request payloads into a pcap.
Open the pcap in Wireshark.
Decode the actual RRC messages (e.g., RRCSetup, RRCReconfiguration) contained in SRB PDUs.
What I tried so far
I can already capture and dump the Tx_Data.request into a pcap file.
Wireshark correctly shows my custom protocol dissector for FAPI messages.
However, if I try to directly call the RRC dissector on the payload, it fails.
If I modify my custom Wireshark plugin DLL (generated using C, nmake), can I just strip headers and call the RRC dissector directly, or do I need to implement the whole MAC → RLC → PDCP chain first?
I suspect you're following an old recipe by using "nmake", Wireshark hasn't used that in a long time, instead the Wireshark build is configured using CMake to generate a VS solution.
What version of Wireshark are you using?
Custom plugin generated using C,nmake is working fine. I'm able to dissect L1 FAPI packets without any issues. I'm using Wireshark 4.4.0