Comment by Cilyan for Actually the correct way to detect how/why a subdissector is being called is to use the pinfo->match_uint or match_string fields. These will tell you, to quote the comment in packet_info.h, the "matched uint for calling subdissector from table".I don't know the Lua API enough to know if that field is exposed to Lua dissectors but I would hope it is...

Thanks a lot. This works actually wonderful. Though according to the official example I used the table to get the dissector and then call it, of course this wouldn't work. One needs to call `DissectorTable:try` so that the parameter is set properly. Otherwise, one gets the value that was used to call the parent dissector, e.g. the tcp port.