myhro / bpf-proxy

Redirect multiple ports to a single listening socket with BPF

BPF Proxy

This is a reimplementation of the jsitnicki/ebpf-summit-2020 echo dispatcher proxy with modern BPF features. It includes many of the improvements made to the ecosystem in the past 3+ years, like:

• BTF, CO-RE and libbpf.
• BPF skeleton.
• Updated map syntax.

Plus:

• Single binary.
• libbpf helpers instead of bpf() syscalls.
• Include sys/pidfd.h instead of custom syscall wrappers.
• No need for bpftool, avoiding hand-editing maps and custom pinning.

Dependencies

$ sudo apt install build-essential clang libbpf-dev

Usage

Start the proxy with ./proxy [pid] [fd] [port [port...]], replacing the arguments with the respective process ID, file descriptor and port numbers:

$ sudo ./proxy 7738 3 77 777
pid: 7738, fd: 3
pid_fd: 3, sock_fd: 4
port: 77
port: 777

On another terminal:

$ nc -vz 127.0.0.1 77
Connection to 127.0.0.1 77 port [tcp/*] succeeded!
$ nc -vz 127.0.0.1 777
Connection to 127.0.0.1 777 port [tcp/moira-update] succeeded!