- Add possibility to configure controller manager to use IPv6 dual stack:
  use `--cluster-cidr="<cidr1>,<cidr2>"`.
  Notes:
  1. Only the first two CIDRs are used (soft limits for Alpha, might be lifted later on).
  2. Only the "RangeAllocator" (default) is allowed as a value for `--cidr-allocator-type`. Cloud allocators are not compatible with IPv6 dual stack

		return fmt.Errorf("interceptionMode invalid: %v", mode)
	}
	return nil
}

func validateCIDRList(cidrs string) error {
	if len(cidrs) > 0 {
		for _, cidr := range strings.Split(cidrs, ",") {
			if _, err := netip.ParsePrefix(cidr); err != nil {
				return fmt.Errorf("failed parsing cidr '%s': %v", cidr, err)
			}
		}
	}
	return nil
}

func splitPorts(portsString string) []string {

	// Set up netlink routes for localhost
	cidrs := []string{"0.0.0.0/0"}
	if cfg.EnableIPv6 {
		// IPv6 may be enabled, but only partially
		v, err := ReadSysctl(ipv6DisabledLo)
		if v != "1" {
			// If we got an error, we will proceed. Maybe it will work anyways
			if err != nil {
				log.Warnf("attempted to read %q got error: %v; attemping to continue", ipv6DisabledLo, err)
			}
			cidrs = append(cidrs, "0::0/0")
		} else {

// allocations when the MultiCIDRRangeAllocator is enabled (see the config for
// kube-controller-manager).  A cluster may have any number of ClusterCIDR
// resources, all of which will be considered when allocating a CIDR for a
// Node.  A ClusterCIDR is eligible to be used for a given Node when the node
// selector matches the node in question and has free CIDRs to allocate.  In

}

// IPBlock describes a particular CIDR (Ex. "192.168.1.0/24","2001:db8::/64") that is allowed
// to the pods matched by a NetworkPolicySpec's podSelector. The except entry describes CIDRs
// that should not be included within this rule.
message IPBlock {
  // cidr is a string representing the IPBlock
  // Valid examples are "192.168.1.0/24" or "2001:db8::/64"
  optional string cidr = 1;

  // a map of client CIDR to server address that is serving this group.
  // This is to help clients reach servers in the most network-efficient way possible.
  // Clients can use the appropriate server address as per the CIDR that they match.
  // In case of multiple matches, clients should use the longest matching CIDR.
  // The server returns only those CIDRs that it thinks that the client can match.

			m = map[string]*matcher.Matcher_OnMatch{}
			for _, rm := range ip.GetRangeMatchers() {
				for _, r := range rm.Ranges {
					cidr := r.AddressPrefix
					pl := r.PrefixLen.GetValue()
					if pl != 32 && pl != 128 {
						cidr += fmt.Sprintf("/%d", pl)
					}
					m[cidr] = rm.OnMatch
				}
			}
		default:
			panic("unhandled")
		}
	}
	outputs := []string{}
	for k, v := range m {

// IPBlock describes a particular CIDR (Ex. "192.168.1.0/24","2001:db8::/64") that is allowed
// to the pods matched by a NetworkPolicySpec's podSelector. The except entry describes CIDRs
// that should not be included within this rule.
message IPBlock {
  // CIDR is a string representing the IP Block
  // Valid examples are "192.168.1.0/24" or "2001:db8::/64"
  optional string cidr = 1;

- `-- kube-controller-manager`
  `--node-cidr-mask-size-ipv4 int32`     Default: 24. Mask size for IPv4 node-cidr in dual-stack cluster.
`--node-cidr-mask-size-ipv6 int32`     Default: 64. Mask size for IPv6 node-cidr in dual-stack cluster.

    These 2 flags can be used only for dual-stack clusters. For non dual-stack clusters, continue to use  `--node-cidr-mask-size` flag to configure the mask size.

}

function cidr_to_ips() {
    CIDR="$1"
    # cidr_to_ips returns a list of single IPs from a CIDR. We skip 1000 (since they are likely to be allocated
    # already to other services), then pick the next 100.
    python3 - <<EOF
from ipaddress import ip_network, IPv6Network;
from itertools import islice;

net = ip_network('$CIDR')
net_bits = 128 if type(net) == IPv6Network else 32;