Cloudflare architecture and how BPF eats the world

After DoS and the load balancing layers, the packets are passed onto the usual Linux TCP / UDP stack. We do our best to use vanilla Linux features, but things get complex when you use thousands of IP addresses on the servers. Soon we will be doing more with eBPF based socket dispatch, eBPF running on Linux TC (Traffic Control) layer and more integration with cgroup eBPF hooks.

Source: blog.cloudflare.com