replace the iptree on the ipallocator

ServiceCIDRs are protected by finalizers and the CIDRs fields are
inmutable once set, only the readiness state impact the allocator
as it can only allocate IPs if any of the ServiceCIDR is ready.

The Add/Update events triggers a reconcilation of the current state
of the ServiceCIDR present in the informers with the existing IP
allocators.

The Delete events are handled directly to update or delete the
corresponing IP allocator.

pkg/api/servicecidr/servicecidr.go

@@ -83,7 +83,7 @@ func ContainsAddress(serviceCIDRLister networkinglisters.ServiceCIDRLister, addr
 	for _, serviceCIDR := range serviceCIDRList {
 		for _, cidr := range serviceCIDR.Spec.CIDRs {
 			if prefix, err := netip.ParsePrefix(cidr); err == nil { // it can not fail since is already validated
-				if prefixContainsIP(prefix, address) {
+				if PrefixContainsIP(prefix, address) {
 					result = append(result, serviceCIDR)
 				}
 			}
@@ -92,12 +92,12 @@ func ContainsAddress(serviceCIDRLister networkinglisters.ServiceCIDRLister, addr
 	return result
 }
 
-// prefixContainsIP returns true if the given IP is contained with the prefix,
+// PrefixContainsIP returns true if the given IP is contained with the prefix,
 // is not the network address and also, if IPv4, is not the broadcast address.
 // This is required (rather than just `prefix.Contains(ip)`) because a ServiceCIDR
 // covering prefix will not allocate those IPs, so a service with one of those IPs
 // can't belong to that ServiceCIDR.
-func prefixContainsIP(prefix netip.Prefix, ip netip.Addr) bool {
+func PrefixContainsIP(prefix netip.Prefix, ip netip.Addr) bool {
 	// if the IP is the network address is not contained
 	if prefix.Masked().Addr() == ip {
 		return false

pkg/api/servicecidr/servicecidr_test.go

@@ -640,7 +640,7 @@ func Test_PrefixContainIP(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := prefixContainsIP(tt.prefix, tt.ip); got != tt.want {
+			if got := PrefixContainsIP(tt.prefix, tt.ip); got != tt.want {
 				t.Errorf("prefixContainIP() = %v, want %v", got, tt.want)
 			}
 		})