Materials by Teodor Janez Podobnik
Explore tutorials, challenges, courses, and more published by this author.
Tutorials by Teodor Janez Podobnik
See all →Different Ways To Deliver Kernel Events from eBPF to User Space
In this tutorial, you’ll learn how eBPF applications send kernel events into user space using perf buffer and ring buffer, exploring their design, trade-offs, and performance implications. You’ll also learn how moderns solutions like Jibril handle high-throughput event delivery.
Building an eBPF/XDP NAT-Based Layer 4 Load Balancer from Scratch
Learn how an eBPF/XDP-based NAT Layer 4 load balancer works by building one from scratch. We implement simple connection tracking, deterministic hashing, and IP/MAC rewriting with a small, easy-to-follow example.
Building an eBPF-based Firewall with LPM Trie–Based IP Range Matching
Learn how to build an eBPF/XDP firewall that filters packets by IP ranges using BPF_MAP_TYPE_LPM_TRIE and longest-prefix matching.
Network Traffic Rate Limiting with eBPF/XDP
Learn how to implement a basic per-client ICMPv6 packet rate limiter using eBPF/XDP. This tutorial shows how to track client activity with eBPF maps and enforce limits directly in the kernel—without any user-space interaction.
Why Does My eBPF Program Work on One Kernel but Fail on Another?
In this tutorial, we look at why eBPF programs can fail across kernel versions due to changes in structs, tracepoints, and function layouts. We look at examples of how these differences cause portability issues and how BPF CO-RE, BTF and vmlinux.h address them.
Challenges by Teodor Janez Podobnik
See all →eBPF Challenge for Beginners
In this challenge, you’ll debug and fix a deliberately “broken” eBPF program, then prove it’s running by identifying its program and map IDs. Along the way, you’ll explore bpftool, check which helpers are supported, and dig into details like the UID of the loader. Finally, you’ll test your knowledge of eBPF maps by recalling the flag that only inserts a key if it doesn’t already exist.
Submissions: 66/209
Skill Paths by Teodor Janez Podobnik
See all →eBPF/XDP Network Skill Path
A hands-on learning path that teaches how to use eBPF and XDP for high-performance, in-kernel packet processing, from protocol parsing to advanced use cases like firewalling, rate limiting, and load balancing.
eBPF Beginner Skill Path
Learn eBPF from the ground up — from writing and running your first program, to storing data in eBPF maps, inspecting and monitoring kernel activity using bpftool and bpftop, and understanding how the verifier ensures safe eBPF execution. Finish with a hands-on challenge to put your new skills to the test.
- 4 Tutorials
- 1 Challenge
- Easy
eBPF CO-RE Skill Path
In this learning path, you’ll go from comparing different tracing program types — tracepoints, raw tracepoints, kprobes, and fprobes — to writing portable eBPF programs that work reliably across environments. You’ll also understand the role of BTF and learn how to make your eBPF code portable even when BTF isn’t available on the target system.