davidcoles/vc5 — reverse-engineered prompt

Build me a Linux network load balancer like VC5. I want one Go binary I can run on a server with one or more network interfaces, point it at a config file, and have it send traffic for virtual IPs to healthy backend servers using Direct Server Return.

It should support IPv4 and IPv6, layer 2 forwarding when the backends are on the same VLAN, and optional layer 3 tunnelling using IP in IP, GRE, FOU, or GUE. The config should define VIPs, backend servers, VLANs, BGP peers, and health checks for HTTP, HTTPS, TCP, UDP, DNS, and simple SYN probes.

When enough backends are healthy, advertise the VIPs over BGP, and withdraw them when they are not. Include a small web status console, Prometheus metrics, and logging. Make it practical to build and run on Linux with XDP/eBPF, with sample configs and clear quickstart commands. Look up current Linux eBPF docs online if needed.