XDP — eBPF-based packet processing in the kernel

XDP — Drops at the Driver

eXpress Data Path (XDP) is eBPF's answer to "in-kernel DPDK." An XDP program runs at the lowest possible point in the Linux network stack — inside the driver, before any sk_buff allocation. The driver hands a raw packet buffer to the XDP program, which decides what to do: pass it up the stack (XDP_PASS), drop it (XDP_DROP), redirect it to another network interface (XDP_REDIRECT), or bounce it back out the same port (XDP_TX). Crucially, because XDP runs before sk_buff allocation, the per-packet overhead of the normal Linux network stack is avoided. On modern hardware with supported drivers…