BPF Linux Learn
I am learning about BPF and I found that the hands-on development process is not straightforward if you are out of the Kernel tree. I want to do everything in C language in my local Linux environment.
The following repository contains a build framework for a BPF program loader and a BPF targets build. The build system is on CMake and tested only on Ubuntu 19.10.
Content
The content of the repository is the following:
| Directory | description |
|---|---|
| bpf-loader/ | A BPF program loader. This program is an adapted copy from the repository https://github.com/pratyushanand/learn-bpf . Kudos to the real author. |
| bpf-targets/ | BPF programs that aims to be loaded in the Kernel. The build process takes every .c file and generate an object with a file name extension .bpf . |
Requirements
Install the following system dependencies:
sudo apt install linux-headers cmake build-essential clang
Build
The build process will build the loader and each BPF kernel program.
$ cd build
$ cmake ../
after the build process the binaries will be found at the following locations
- build/bin/
- build/bpf-programs/
Author
Eduardo Silva eduardo@monkey.io
F.A.Q
bpf_trace_printk() not working
The first example is not working, the program prints the following output:
bpf_load_program() err=22
BPF_STX uses reserved fields
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
root cause
likely the Kernel don't have KPROBE Events enabled properly, check the Kernel build config with:
$ cat /boot/config-`uname -r`|grep KPROBE_EVENTS_ON_NOTRACE