modifying an existing protocol

[whitewalter1950]

Hi
i want to add a function to a specific protocol lets say skype for example so that when a packet of that protocol is detected my function is triggered. i added my function into the protocol code "someProtocol.c" in the nDPI/src/lib/protocols directory then added any headers needed for my function to work. when trying to install, the "make" is done without errors however when reaching the step NDPI_PATH=....../nDPI make i am prompted with a warning that says:
WARNING: "myFunctionName" [path/to/ndpi/src/xt_ndpi.ko] undefined!
what am i supposed to do in order to make my function run whenever a packet of that specific protocol is detected by ndpi
thanks in advance