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Kernel Instrumentation · hard

3. eBPF (Extended Berkeley Packet Filter) & XDP

High-speed programmable kernel packet processing and tracing.

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eBPF runs sandboxed bytecode inside the Linux kernel. XDP (eXpress Data Path) executes eBPF filters at the network driver level *before* allocating socket buffers (`sk_buff`), dropping millions of DDoS packets per second with wire speed.

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Check your understanding

1. Where does XDP (eXpress Data Path) execute eBPF programs in the Linux networking stack?
At the lowest network device driver level before sk_buff memory allocationIn user spaceInside the web server processIn the browser
2. What safety mechanism does the Linux kernel run before loading an eBPF program?
eBPF Verifier (proves memory safety, bounds checks, and termination)An antivirus scanA GPU benchmarkA TLS handshake

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