eBPF Networking and Cilium Architecture

eBPF Networking and Cilium Architecture is a skill for Claude Code, Codex from j4flmao/agent-skills. It costs 23 tokens per session (613 once invoked), scanned A, original, MIT.

A guide to eBPF, which runs verified programs inside the Linux kernel, and Cilium, a networking and security system built on it. It explains how network packets can be inspected or changed early in their path.

In plain words
What is it for?
Use it to understand XDP hooks, packet actions, Cilium architecture, container networking, and kernel-level network security policies.
Why use it?
It makes low-level container networking and packet handling easier to reason about. This helps when choosing where to enforce traffic rules or improve network performance.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to understand XDP hooks, packet actions, Cilium architecture, container networking, and kernel-level network security policies.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/j4flmao/agent-skills/ebpf-networking
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add j4flmao/agent-skills --skill ebpf-networking
Clone the repo
git clone --depth 1 https://github.com/j4flmao/agent-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for eBPF Networking and Cilium Architecture

README.md
[![agentmods](https://agentmods.dev/badge/skills/j4flmao/agent-skills/ebpf-networking/github.svg)](https://agentmods.dev/skills/j4flmao/agent-skills/ebpf-networking)
Your own site
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/ebpf-networking"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/ebpf-networking/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for eBPF Networking and Cilium Architecture

Your own site · 80×15
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/ebpf-networking"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/ebpf-networking.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 613 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00023 $0.00613
Opus 5 $0.00012 $0.00307
Sonnet 5 $0.00005 $0.00123
Haiku 4.5 $0.00002 $0.00061

Measured 8d ago against content hash 2de72bf4e79a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

eBPF Networking and Cilium Architecture scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/cloud-native/ebpf-networking/SKILL.md · 42 lines

How it starts

The opening of the file, as written. The whole thing — 42 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cilium & eBPF Networking: Kernel Space Packet Processing

eBPF (Extended Berkeley Packet Filter) Fundamentals

eBPF allows sandboxed execution of user-defined bytecode within the Linux kernel. Programs are verified by the kernel's eBPF verifier to ensure safety (no infinite loops, bounds checking) and compiled via JIT (Just-In-Time) into native machine code. In networking, eBPF programs can be attached to various hooks (XDP, TC, cgroup socket hooks) to inspect, modify, or drop packets before they traverse the full kernel network stack.

XDP (eXpress Data Path) Hooks

XDP provides the earliest possible interception point in the Linux kernel network data path, executing eBPF programs directly within the network interface controller (NIC) driver (or even offloaded to hardware).

  • XDP_DROP: Discard packets at wire speed (ideal for DDoS mitigation).
  • XDP_PASS: Pass packets to the standard network stack.
  • XDP_TX: Bounce packets back out the same interface.
  • XDP_REDIRECT: Forward packets to another interface or CPU queue.

Cilium Architecture

Cilium heavily utilizes eBPF and XDP to implement high-performance container networking, security policies, and load balancing (replacing kube-proxy). Cilium attaches eBPF programs to the TC (Traffic Control) ingress/egress hooks on virtual ethernet (veth) pairs associated with pods. This allows for identity-based security policies enforced via eBPF maps rather than iptables rules. When combined with XDP, Cilium provides DSR (Direct Server Return) for LoadBalancer services, bypassing the standard netfilter stack entirely.

Architecture Map

%%{init: {"theme": "default", "flowchart": {"useMaxWidth": true}}}%%
flowchart TD
    NIC[Network Interface Card] -->|Driver RX| XDP[XDP eBPF Hook]
    XDP -->|XDP_PASS| TC_Ingress[TC Ingress eBPF Hook]
    XDP -->|XDP_DROP| Dropped[Packet Dropped - DDoS]
    
    subgraph "Host Kernel Space"
        TC_Ingress --> Routing[IP Routing Subsystem]
        Routing --> TC_Egress[TC Egress eBPF Hook]
        TC_Egress --> VethHost[Host Veth Interface]
    end
    
    VethHost -- Link --> VethPod[Pod Veth Interface]
    
    CiliumAgent[Cilium Agent - User Space] -. "Updates BPF Maps" .-> TC_Ingress
    CiliumAgent -. "Updates BPF Maps" .-> XDP
    CiliumAgent -. "Listens to K8s API" .-> K8sAPI[Kubernetes API Server]

Read the full file on GitHub · 42 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 42 lines · 23 tokens per session scan A 2de72bf4e79a

Subscribe to this mod's changes

eBPF Networking and Cilium Architecture is a skill published in the GitHub repository j4flmao/agent-skills (23 stars, last pushed 5d ago), licensed MIT. It adds 23 tokens to every session and 613 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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