如何获取 Linux 内核的 bpf_helpers.h 头文件？

Question

I am developing an eBPF program on an Ubuntu machine:

$ uname -a
Linux ubuntu-bionic 4.18.0-16-generic #17~18.04.1-Ubuntu SMP Tue Feb 12 13:35:51 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

To do this I need both bpf.h for a number of definitions as well bpf_helpers.h for helper function definitions. I installed a new kernel with the headers:

apt-get update -y
apt-get install -y linux-image-4.18.0-16-generic linux-headers-4.18.0-16-generic

The headers include bpf.h :

$ find /usr/src/linux-headers-4.18.0-16 -name bpf.h
/usr/src/linux-headers-4.18.0-16/include/uapi/linux/bpf.h
/usr/src/linux-headers-4.18.0-16/include/linux/bpf.h

but not bpf_helpers.h :

$ find /usr/src/linux-headers-4.18.0-16 -name bpf_helpers.h

How can I get this file for my kernel and why is it not included with the distribution headers?

I could checkout a particular version of the Linux kernel or get the file from master but the distribution could have potentially made changes to upstream which makes me uncomfortable doing this.

Answer 1

bpf_helpers.h is not distributed with the kernel headers . As suggested by agg3l in comments, you could copy it from Ubuntu's linux-source package .

Answer 2

On Ubuntu I installed libbpf-dev to get that header:

sudo apt-get install libbpf-dev

$ apt-file list libbpf-dev | grep bpf_helpers.h
libbpf-dev: /usr/include/bpf/bpf_helpers.h