TL;DR: I need to add .c and maybe .h files to linux/net and linux/include/net but after make clean they are gone.
I'm sorry if I am asking stupid question or maybe some that was asked previously, but I have been searching in documentation how to solve my problem and I kind of stuck.
For my studies I need to add new packet schedulers to OpenWRT. I tried to simply create .c files in build_dir/target-mips_24kc_musl/linux-ar71xx-mikrotik/linux-4.9.123/net/sched but after call "make clean" in the root of repository, my files are gone. If I understand well, the sources are removed and during "make", are downloaded and ten built. My question is - how to add new files to be sure that they won't be removed during clean? My first idea was to create bash script which will patch the sources with my changes, but this solution is not the best idea.