L4Drop: XDP DDoS Mitigations

What this post added

Introduced L4Drop, a new XDP-based DDoS mitigation tool that replaces the previous Floodgate kernel bypass system. L4Drop leverages eBPF to run packet filtering logic directly in the network card driver, enabling high-speed packet dropping and sampling without kernel bypass or busy polling. It includes a BPF to C compiler for easier integration of existing BPF filters and a mechanism to modify ELF files for dynamic rule enabling/disabling based on location.