xdp.md

XDP (eXpress Data Path) - Kernel-Level Packet Filtering

• eBPF-based packet processing at network driver level
• Pre-kernel stack filtering for ultra-low latency
• API Key Validation at kernel level before reaching user space
• Location: /gpuf-s/src/xdp/
• Use Case: High-performance request validation and DDoS protection

# Compile XDP program
cd gpuf-s/src/xdp
make deps  # First time only
make

# Load XDP filter
sudo ip link set dev <interface> xdp obj xdp_auth_filter.o sec xdp

# Add API key to XDP map
sudo bpftool map update name api_keys key hex 31 32 33 34 35 36 37 38 39 30 30 30 30 30 30 30 value hex 01