Go libbpf-tools

An attempt to implement a Go frontend for libbpf-tools narrated in blog posts:

Start a virtual machine, install Clang and Go.

$ vagrant up
$ vagrant ssh
$ sudo apt-get update
$ sudo apt-get install clang
$ sudo snap install go --classic
$ uname -nr
ubuntu-groovy 5.8.0-53-generic
$ clang -v
Ubuntu clang version 11.0.0-2

Compile C BPF program into BPF bytecode and generate Go files with bpf2go tool.

$ cd /vagrant/
$ BPF_CFLAGS='-D__TARGET_ARCH_x86' go generate ./cmd/tcpconnect/
$ sudo go run ./cmd/tcpconnect -timestamp -print-uid
TIME(s)  UID   PID    COMM         IP SADDR            DADDR            DPORT
0.000    1000  240332 curl         6  ::1              ::1              8000
3.079    1000  240334 curl         4  127.0.0.1        127.0.0.1        8000

Note, the headers were copied from the following sources.

$ git clone git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/groovy
$ cp ./groovy/tools/lib/bpf/bpf_helpers.h ./headers/bpf
$ cp ./groovy/tools/lib/bpf/bpf_core_read.h ./headers/bpf
$ cp ./groovy/tools/lib/bpf/bpf_tracing.h ./headers/bpf
$ git clone https://github.com/libbpf/libbpf.git
$ cp ./libbpf/src/bpf_helper_defs.h ./headers/bpf

vmlinux.h was generated as follows.

$ sudo apt-get install linux-tools-common linux-tools-5.8.0-53-generic
$ bpftool btf dump file /sys/kernel/btf/vmlinux format c > ./headers/vmlinux.h