What is eBPF(Hint: eBPF Is Awesome)

The reason I ventured into kernel programming was to explore eBPF—a remarkably powerful and flexible tool. Unlike traditional user-space tools, eBPF offers a way to interact with the Linux kernel in a highly controlled yet deeply integrated manner. Its potential for observability, security, and high-performance networking is what amazed me and drew me in. Let’s learn a little bit more about it to know it’s true potential.

But What is eBPF?

eBPF Stands for extended Berkeley Packet Filter which is an advancement from the existing BPF tool. BPF is already being used for packet tracking but with eBPF the functionality got hugely upgraded.

The Key advantage of this tool over any other of similar category is that, this application runs at kernel space instead of running in user-space which gives it extended privileges and makes it more powerful than any other network/packet tracing tools that exist.

Of course with this power of running at kernel space and the privileges there has to be some guardrails to protect our system incase of any mishap and by design that is already taken care. eBPF runs in a safe sandboxed environment. It has 2 major functionalities:

1. In terms of security context as discussed before

2. Modularity of the programs that run in the kernel space.

These functionalities make the programs by eBPF very easy to inject at particular locations and easy to remove as well.

What is XDP?

XDP stands for eXpress Data Path is a technology that is introduced with eBPF and build on top of BPF and is an amazing tool for packet packet processing with unmatched speed with the ability to process them at the earliest input point(Direct processing at Driver level is possible!!) to give some context, The throughput is roughly 5 Million Packets per second where as XDP has 15 Million Packets per second and is more flexible that any application running in the userspace.

There’s more to XDP, of course—like the different return values (XDP_PASS, XDP_DROP, XDP_TX, XDP_ABORTED, etc.) and the various hook points you can use. But the main takeaway is this: it’s one of the most high-performance, low-latency networking tools you can get your hands on.

Conclusion

Honestly, I feel like the possibilities with eBPF are endless. It’s modular, secure, lightweight, and fast—a rare combo. I do recommend experimenting with it inside a VM at first, just to stay safe while learning. There’s a whole world to explore: from Traffic Control and bpftool, to tracking the journey of a packet from hardware all the way to user space.

Understanding the kernel's internals is essential if you want to build real tools or services in this space—and eBPF gives you that window in, without having to write kernel modules or reboot your system every time.

Here are some additional beginner-friendly resources to deep dive and get to know more.

1. The Complete eBPF Function Reference

2. Networking with eBPF

3. eBPF and more

4. Introduction to eBPF(video)

Have fun exploring—there’s a lot to learn, but it’s absolutely worth it.