GetLoadBalancerSourceRanges verifies and parses the AnnotationLoadBalancerSourceRangesKey annotation from a service, extracting the source ranges to allow, and if not present returns a default (allow-all) value.

IsAllowAll checks whether the netsets.IPNet allows traffic from 0.0.0.0/0.

AnnotationLoadBalancerSourceRangesKey is the key of the annotation on a service to set allowed ingress ranges on their LoadBalancers It should be a comma-separated list of CIDRs, e.g.