bpf-developer-tutorial/20-tc

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layout	title	date	category	author	tags	summary
post	tc	2022-10-10 16:18	bpftools	yunwei37	bpftools tc example	a minimal example of a BPF application use tc

tc (short for Traffic Control) is an example of handling ingress network traffics. It creates a qdisc on the lo interface and attaches the tc_ingress BPF program to it. It reports the metadata of the IP packets that coming into the lo interface.

$ sudo ecli ./package.json
...
Successfully started! Please run `sudo cat /sys/kernel/debug/tracing/trace_pipe` to see output of the BPF program.
......

The tc output in /sys/kernel/debug/tracing/trace_pipe should look something like this:

$ sudo cat /sys/kernel/debug/tracing/trace_pipe
            node-1254811 [007] ..s1 8737831.671074: 0: Got IP packet: tot_len: 79, ttl: 64
            sshd-1254728 [006] ..s1 8737831.674334: 0: Got IP packet: tot_len: 79, ttl: 64
            sshd-1254728 [006] ..s1 8737831.674349: 0: Got IP packet: tot_len: 72, ttl: 64
            node-1254811 [007] ..s1 8737831.674550: 0: Got IP packet: tot_len: 71, ttl: 64

Compile and Run

Compile:

docker run -it -v `pwd`/:/src/ yunwei37/ebpm:latest

or compile with ecc:

$ ecc tc.bpf.c
Compiling bpf object...
Packing ebpf object and config into package.json...

Run:

sudo ecli ./package.json