Xdp

Introduction

I’ve been working on a new project that required high-performance UDP load balancing with dynamic weight adjustment. Traditional userspace load balancers introduce latency that’s unacceptable for our use case, so I decided to implement a kernel-level solution using eBPF (extended Berkeley Packet Filter).

The result is ebpflb_udp_wrr, an eBPF-based UDP load balancer that distributes incoming UDP traffic to local listeners using a weighted round-robin algorithm.

Why eBPF and XDP?

eBPF has revolutionized how we can extend kernel functionality without writing kernel modules or modifying the kernel source. Combined with XDP (eXpress Data Path), we can process packets at the earliest possible point in the networking stack—right when they arrive at the network interface—minimizing latency.