Getting Cloudflare Tunnels to connect to the Cloudflare Network with QUIC

What this post added

This post details the successful integration of QUIC (UDP-based) into Cloudflare Tunnel, addressing performance limitations and Head-of-Line blocking inherent in the previous TCP/HTTP/2 approach. It highlights a critical debugging process involving UDP's connectionless nature and Linux kernel's source IP selection heuristics, culminating in the implementation of explicit source address control using `sendmsg` and `recvmsg` system calls to ensure reliable connectivity.