code: func allowNondistributableArtifacts(config *serviceConfig, hostname string) bool {
  	for _, h := range config.AllowNondistributableArtifactsHostnames {
  		if h == hostname {
  			return true
  		}
  	}
  
  	return isCIDRMatch(config.AllowNondistributableArtifactsCIDRs, hostname)
  }
docs: // allowNondistributableArtifacts returns true if the provided hostname is part of the list of registries
  // that allow push of nondistributable artifacts.
  //
  // The list can contain elements with CIDR notation to specify a whole subnet. If the subnet contains an IP
  // of the registry specified by hostname, true is returned.
  //
  // hostname should be a URL.Host (`host:port` or `host`) where the `host` part can be either a domain name
  // or an IP address. If it is a domain name, then it will be resolved to IP addresses for matching. If
  // resolution fails, CIDR matching is not performed.