Code Archaeology

Jul 15, 2025 · Backend Development

AF_XDP Explained: Zero-Copy Packet Processing via eBPF Ring Buffers

This article explains AF_XDP, the user-space socket interface for XDP that enables zero-copy packet processing via shared memory (UMEM) and four single-producer/single-consumer ring queues (RX, TX, FILL, COMPLETION), detailing the packet receive/send flow and the BPF_MAP_TYPE_XSKMAP for redirecting packets to user space.