parthpower/ebpf-stuff

stuff with eBPF and tc

just some adventures with eBPF and tc because why not

What does it do?

7/4/2024: attaches a very crappy ebpf program on tc filter to measure time difference between packets (i.e. latency)

Quick start

# debian/*buntu
# install ebpf stuff
# apt install -y clang llvm libelf-dev libbpf-dev bpfcc-tools linux-headers-$(uname -r) gcc

# get latest bpftools because it has more features like prog prof,
# curl -Lfs https://github.com/libbpf/bpftool/releases/download/v7.4.0/bpftool-v7.4.0-amd64.tar.gz | tar -xzv
# chmod +x ./bpftool

# enable bpf profiling
# sudo sysctl -w kernel.bpf_stats_enabled=1

# build stuff

# set IFNAME to something..
# it does sudo so be careful there

make IFNAME="ens1"

# FYI read_count doesn't really work, use "bpftool map dump name time_deltas"

some quirks

DEBUG=1 very slow!

about 10x slower :(

lvm-objdump --no-show-raw-insn --section=classifier -S ebpf_nfilter.o to see assembly