// 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 {

	case redirectModeREDIRECT:
	case redirectModeTPROXY:
	default:
		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
}

// 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
// case of multiple matching ClusterCIDR resources, the allocator will attempt
// to break ties using internal heuristics, but any ClusterCIDR whose node
// selector matches the Node may be used.

	for _, addr := range addrs {
		ipList.Add(addr)
	}

	return ipList, err
}

// sortIPs - sort ips based on higher octets.
// The logic to sort by last octet is implemented to
// prefer CIDRs with higher octets, this in-turn skips the
// localhost/loopback address to be not preferred as the
// first ip on the list. Subsequently this list helps us print
// a user friendly message with appropriate values.

// 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;

  // except is a slice of CIDRs that should not be included within an IPBlock
  // Valid examples are "192.168.1.0/24" or "2001:db8::/64"

// 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;

  // Except is a slice of CIDRs that should not be included within an IP Block

  // 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.
  // For example: the master will return an internal IP CIDR only, if the client reaches the server using an internal IP.

### Documentation

- Node `ipam` controller now exposes metrics `cidrset_cidrs_max_total` and `multicidrset_cidrs_max_total` with information about the max number of CIDRs that can be allocated. ([#112260](https://github.com/kubernetes/kubernetes/pull/112260), [@aryan9600](https://github.com/aryan9600))

- Added alpha-level support for the SuccessPolicy in Jobs.
   ([#123412](https://github.com/kubernetes/kubernetes/pull/123412), [@tenzen-y](https://github.com/tenzen-y))
- Added the `CEL` library for IP Addresses and CIDRs. This was made available for use starting from version `1.31`.
   ([#121912](https://github.com/kubernetes/kubernetes/pull/121912), [@JoelSpeed](https://github.com/JoelSpeed))