LB Source Ranges: Move validation into API layer

Had to move other things around too to avoid a weird api ->
cloudprovider dependency.

Also adding fixes per code reviews.

(This is a squash of the previously approved commits)

pkg/api/service/annotations.go

@@ -0,0 +1,28 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package service
+
+const (
+	// 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. `0.0.0.0/0` to
+	// allow full access (the default) or `18.0.0.0/8,56.0.0.0/8` to allow
+	// access only from the CIDRs currently allocated to MIT & the USPS.
+	//
+	// Not all cloud providers support this annotation, though AWS & GCE do.
+	AnnotationLoadBalancerSourceRangesKey = "service.beta.kubernetes.io/load-balancer-source-ranges"
+)

pkg/api/service/util.go

@@ -0,0 +1,54 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package service
+
+import (
+	"fmt"
+	"strings"
+
+	netsets "k8s.io/kubernetes/pkg/util/net/sets"
+)
+
+const (
+	defaultLoadBalancerSourceRanges = "0.0.0.0/0"
+)
+
+// IsAllowAll checks whether the netsets.IPNet allows traffic from 0.0.0.0/0
+func IsAllowAll(ipnets netsets.IPNet) bool {
+	for _, s := range ipnets.StringSlice() {
+		if s == "0.0.0.0/0" {
+			return true
+		}
+	}
+	return false
+}
+
+// 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.
+func GetLoadBalancerSourceRanges(annotations map[string]string) (netsets.IPNet, error) {
+	val := annotations[AnnotationLoadBalancerSourceRangesKey]
+	val = strings.TrimSpace(val)
+	if val == "" {
+		val = defaultLoadBalancerSourceRanges
+	}
+	specs := strings.Split(val, ",")
+	ipnets, err := netsets.ParseIPNets(specs...)
+	if err != nil {
+		return nil, fmt.Errorf("Service annotation %s:%s is not valid. Expecting a comma-separated list of source IP ranges. For example, 10.0.0.0/24,192.168.2.0/24", AnnotationLoadBalancerSourceRangesKey, val)
+	}
+	return ipnets, nil
+}

pkg/api/service/util_test.go

@@ -0,0 +1,92 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package service
+
+import (
+	"testing"
+
+	netsets "k8s.io/kubernetes/pkg/util/net/sets"
+)
+
+func TestGetLoadBalancerSourceRanges(t *testing.T) {
+	checkError := func(v string) {
+		annotations := make(map[string]string)
+		annotations[AnnotationLoadBalancerSourceRangesKey] = v
+		_, err := GetLoadBalancerSourceRanges(annotations)
+		if err == nil {
+			t.Errorf("Expected error parsing: %q", v)
+		}
+	}
+	checkError("10.0.0.1/33")
+	checkError("foo.bar")
+	checkError("10.0.0.1/32,*")
+	checkError("10.0.0.1/32,")
+	checkError("10.0.0.1/32, ")
+	checkError("10.0.0.1")
+
+	checkOK := func(v string) netsets.IPNet {
+		annotations := make(map[string]string)
+		annotations[AnnotationLoadBalancerSourceRangesKey] = v
+		cidrs, err := GetLoadBalancerSourceRanges(annotations)
+		if err != nil {
+			t.Errorf("Unexpected error parsing: %q", v)
+		}
+		return cidrs
+	}
+	cidrs := checkOK("192.168.0.1/32")
+	if len(cidrs) != 1 {
+		t.Errorf("Expected exactly one CIDR: %v", cidrs.StringSlice())
+	}
+	cidrs = checkOK("192.168.0.1/32,192.168.0.1/32")
+	if len(cidrs) != 1 {
+		t.Errorf("Expected exactly one CIDR (after de-dup): %v", cidrs.StringSlice())
+	}
+	cidrs = checkOK("192.168.0.1/32,192.168.0.2/32")
+	if len(cidrs) != 2 {
+		t.Errorf("Expected two CIDRs: %v", cidrs.StringSlice())
+	}
+	cidrs = checkOK("  192.168.0.1/32 , 192.168.0.2/32   ")
+	if len(cidrs) != 2 {
+		t.Errorf("Expected two CIDRs: %v", cidrs.StringSlice())
+	}
+	cidrs = checkOK("")
+	if len(cidrs) != 1 {
+		t.Errorf("Expected exactly one CIDR: %v", cidrs.StringSlice())
+	}
+	if !IsAllowAll(cidrs) {
+		t.Errorf("Expected default to be allow-all: %v", cidrs.StringSlice())
+	}
+}
+
+func TestAllowAll(t *testing.T) {
+	checkAllowAll := func(allowAll bool, cidrs ...string) {
+		ipnets, err := netsets.ParseIPNets(cidrs...)
+		if err != nil {
+			t.Errorf("Unexpected error parsing cidrs: %v", cidrs)
+		}
+		if allowAll != IsAllowAll(ipnets) {
+			t.Errorf("IsAllowAll did not return expected value for %v", cidrs)
+		}
+	}
+	checkAllowAll(false, "10.0.0.1/32")
+	checkAllowAll(false, "10.0.0.1/32", "10.0.0.2/32")
+	checkAllowAll(false, "10.0.0.1/32", "10.0.0.1/32")
+
+	checkAllowAll(true, "0.0.0.0/0")
+	checkAllowAll(true, "192.168.0.0/0")
+	checkAllowAll(true, "192.168.0.1/32", "0.0.0.0/0")
+}

pkg/api/validation/validation.go

@@ -29,6 +29,7 @@ import (
 
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/resource"
+	apiservice "k8s.io/kubernetes/pkg/api/service"
 	"k8s.io/kubernetes/pkg/capabilities"
 	"k8s.io/kubernetes/pkg/labels"
 	"k8s.io/kubernetes/pkg/util/intstr"
@@ -1736,6 +1737,12 @@ func ValidateService(service *api.Service) field.ErrorList {
 		nodePorts[key] = true
 	}
 
+	_, err := apiservice.GetLoadBalancerSourceRanges(service.Annotations)
+	if err != nil {
+		v := service.Annotations[apiservice.AnnotationLoadBalancerSourceRangesKey]
+		allErrs = append(allErrs, field.Invalid(field.NewPath("metadata", "annotations").Key(apiservice.AnnotationLoadBalancerSourceRangesKey), v, "must be a comma separated list of CIDRs e.g. 192.168.0.0/16,10.0.0.0/8"))
+	}
+
 	return allErrs
 }
 

pkg/api/validation/validation_test.go

@@ -25,6 +25,7 @@ import (
 
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/resource"
+	"k8s.io/kubernetes/pkg/api/service"
 	"k8s.io/kubernetes/pkg/api/testapi"
 	"k8s.io/kubernetes/pkg/api/unversioned"
 	"k8s.io/kubernetes/pkg/capabilities"
@@ -2877,6 +2878,34 @@ func TestValidateService(t *testing.T) {
 			},
 			numErrs: 1,
 		},
+		{
+			name: "valid LoadBalancer source range annotation",
+			tweakSvc: func(s *api.Service) {
+				s.Annotations[service.AnnotationLoadBalancerSourceRangesKey] = "1.2.3.4/8,  5.6.7.8/16"
+			},
+			numErrs: 0,
+		},
+		{
+			name: "empty LoadBalancer source range annotation",
+			tweakSvc: func(s *api.Service) {
+				s.Annotations[service.AnnotationLoadBalancerSourceRangesKey] = ""
+			},
+			numErrs: 0,
+		},
+		{
+			name: "invalid LoadBalancer source range annotation (hostname)",
+			tweakSvc: func(s *api.Service) {
+				s.Annotations[service.AnnotationLoadBalancerSourceRangesKey] = "foo.bar"
+			},
+			numErrs: 1,
+		},
+		{
+			name: "invalid LoadBalancer source range annotation (invalid CIDR)",
+			tweakSvc: func(s *api.Service) {
+				s.Annotations[service.AnnotationLoadBalancerSourceRangesKey] = "1.2.3.4/33"
+			},
+			numErrs: 1,
+		},
 	}
 
 	for _, tc := range testCases {

pkg/cloudprovider/cloud.go

@@ -26,20 +26,6 @@ import (
 	"k8s.io/kubernetes/pkg/types"
 )
 
-const (
-	// The value of a LBAnnotationAllowSourceRange annotation determines
-	// the source IP ranges to allow to access a service exposed as
-	// type=LoadBalancer (when accesssed through the LoadBalancer created
-	// by the cloud provider).
-	//
-	// It should be a comma-separated list of CIDRs, e.g. `0.0.0.0/0` to
-	// allow full access (the default) or `18.0.0.0/8,56.0.0.0/8` to allow
-	// access only from the CIDRs currently allocated to MIT & the USPS.
-	//
-	// Not all cloud providers support this annotation, though AWS & GCE do.
-	LBAnnotationAllowSourceRange = "service.beta.kubernetes.io/load-balancer-source-ranges"
-)
-
 // Interface is an abstract, pluggable interface for cloud providers.
 type Interface interface {
 	// LoadBalancer returns a balancer interface. Also returns true if the interface is supported, false otherwise.

pkg/cloudprovider/providers/aws/aws.go

@@ -47,6 +47,7 @@ import (
 	"k8s.io/kubernetes/pkg/util/sets"
 
 	"github.com/golang/glog"
+	"k8s.io/kubernetes/pkg/api/service"
 	"k8s.io/kubernetes/pkg/api/unversioned"
 )
 
@@ -1979,7 +1980,7 @@ func (s *AWSCloud) EnsureLoadBalancer(name, region string, publicIP net.IP, port
 		return nil, err
 	}
 
-	sourceRanges, err := cloudprovider.GetSourceRangeAnnotations(annotations)
+	sourceRanges, err := service.GetLoadBalancerSourceRanges(annotations)
 	if err != nil {
 		return nil, err
 	}

pkg/cloudprovider/providers/gce/gce.go

@@ -30,10 +30,12 @@ import (
 	"time"
 
 	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/service"
 	"k8s.io/kubernetes/pkg/api/unversioned"
 	"k8s.io/kubernetes/pkg/cloudprovider"
 	"k8s.io/kubernetes/pkg/types"
 	utilerrors "k8s.io/kubernetes/pkg/util/errors"
+	netsets "k8s.io/kubernetes/pkg/util/net/sets"
 	"k8s.io/kubernetes/pkg/util/sets"
 	"k8s.io/kubernetes/pkg/util/wait"
 
@@ -577,7 +579,7 @@ func (gce *GCECloud) EnsureLoadBalancer(name, region string, requestedIP net.IP,
 	// is because the forwarding rule is used as the indicator that the load
 	// balancer is fully created - it's what getLoadBalancer checks for.
 	// Check if user specified the allow source range
-	sourceRanges, err := cloudprovider.GetSourceRangeAnnotations(annotations)
+	sourceRanges, err := service.GetLoadBalancerSourceRanges(annotations)
 	if err != nil {
 		return nil, err
 	}
@@ -740,7 +742,7 @@ func translateAffinityType(affinityType api.ServiceAffinity) string {
 	}
 }
 
-func (gce *GCECloud) firewallNeedsUpdate(name, serviceName, region, ipAddress string, ports []*api.ServicePort, sourceRanges cloudprovider.IPNetSet) (exists bool, needsUpdate bool, err error) {
+func (gce *GCECloud) firewallNeedsUpdate(name, serviceName, region, ipAddress string, ports []*api.ServicePort, sourceRanges netsets.IPNet) (exists bool, needsUpdate bool, err error) {
 	fw, err := gce.service.Firewalls.Get(gce.projectID, makeFirewallName(name)).Do()
 	if err != nil {
 		if isHTTPErrorCode(err, http.StatusNotFound) {
@@ -764,7 +766,7 @@ func (gce *GCECloud) firewallNeedsUpdate(name, serviceName, region, ipAddress st
 	}
 	// The service controller already verified that the protocol matches on all ports, no need to check.
 
-	actualSourceRanges, err := cloudprovider.ParseIPNetSet(fw.SourceRanges)
+	actualSourceRanges, err := netsets.ParseIPNets(fw.SourceRanges...)
 	if err != nil {
 		// This really shouldn't happen... GCE has returned something unexpected
 		glog.Warningf("Error parsing firewall SourceRanges: %v", fw.SourceRanges)
@@ -852,7 +854,7 @@ func (gce *GCECloud) createTargetPool(name, serviceName, region string, hosts []
 	return nil
 }
 
-func (gce *GCECloud) createFirewall(name, region, desc string, sourceRanges cloudprovider.IPNetSet, ports []*api.ServicePort, hosts []*gceInstance) error {
+func (gce *GCECloud) createFirewall(name, region, desc string, sourceRanges netsets.IPNet, ports []*api.ServicePort, hosts []*gceInstance) error {
 	firewall, err := gce.firewallObject(name, region, desc, sourceRanges, ports, hosts)
 	if err != nil {
 		return err
@@ -870,7 +872,7 @@ func (gce *GCECloud) createFirewall(name, region, desc string, sourceRanges clou
 	return nil
 }
 
-func (gce *GCECloud) updateFirewall(name, region, desc string, sourceRanges cloudprovider.IPNetSet, ports []*api.ServicePort, hosts []*gceInstance) error {
+func (gce *GCECloud) updateFirewall(name, region, desc string, sourceRanges netsets.IPNet, ports []*api.ServicePort, hosts []*gceInstance) error {
 	firewall, err := gce.firewallObject(name, region, desc, sourceRanges, ports, hosts)
 	if err != nil {
 		return err
@@ -888,7 +890,7 @@ func (gce *GCECloud) updateFirewall(name, region, desc string, sourceRanges clou
 	return nil
 }
 
-func (gce *GCECloud) firewallObject(name, region, desc string, sourceRanges cloudprovider.IPNetSet, ports []*api.ServicePort, hosts []*gceInstance) (*compute.Firewall, error) {
+func (gce *GCECloud) firewallObject(name, region, desc string, sourceRanges netsets.IPNet, ports []*api.ServicePort, hosts []*gceInstance) (*compute.Firewall, error) {
 	allowedPorts := make([]string, len(ports))
 	for ix := range ports {
 		allowedPorts[ix] = strconv.Itoa(ports[ix].Port)
@@ -1206,7 +1208,7 @@ func (gce *GCECloud) GetFirewall(name string) (*compute.Firewall, error) {
 }
 
 // CreateFirewall creates the given firewall rule.
-func (gce *GCECloud) CreateFirewall(name, desc string, sourceRanges cloudprovider.IPNetSet, ports []int64, hostNames []string) error {
+func (gce *GCECloud) CreateFirewall(name, desc string, sourceRanges netsets.IPNet, ports []int64, hostNames []string) error {
 	region, err := GetGCERegion(gce.localZone)
 	if err != nil {
 		return err
@@ -1235,7 +1237,7 @@ func (gce *GCECloud) DeleteFirewall(name string) error {
 
 // UpdateFirewall applies the given firewall rule as an update to an existing
 // firewall rule with the same name.
-func (gce *GCECloud) UpdateFirewall(name, desc string, sourceRanges cloudprovider.IPNetSet, ports []int64, hostNames []string) error {
+func (gce *GCECloud) UpdateFirewall(name, desc string, sourceRanges netsets.IPNet, ports []int64, hostNames []string) error {
 	region, err := GetGCERegion(gce.localZone)
 	if err != nil {
 		return err

pkg/cloudprovider/providers/openstack/openstack.go

@@ -45,6 +45,7 @@ import (
 	"github.com/golang/glog"
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/resource"
+	"k8s.io/kubernetes/pkg/api/service"
 	"k8s.io/kubernetes/pkg/cloudprovider"
 	"k8s.io/kubernetes/pkg/types"
 )
@@ -685,12 +686,12 @@ func (lb *LoadBalancer) EnsureLoadBalancer(name, region string, loadBalancerIP n
 		return nil, fmt.Errorf("unsupported load balancer affinity: %v", affinity)
 	}
 
-	sourceRanges, err := cloudprovider.GetSourceRangeAnnotations(annotations)
+	sourceRanges, err := service.GetLoadBalancerSourceRanges(annotations)
 	if err != nil {
 		return nil, err
 	}
 
-	if !cloudprovider.IsAllowAll(sourceRanges) {
+	if !service.IsAllowAll(sourceRanges) {
 		return nil, fmt.Errorf("Source range restrictions are not supported for openstack load balancers")
 	}
 

pkg/cloudprovider/utils.go

@@ -1,99 +0,0 @@
-/*
-Copyright 2016 The Kubernetes Authors All rights reserved.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package cloudprovider
-
-import (
-	"fmt"
-	"net"
-	"strings"
-)
-
-const (
-	defaultLBSourceRange = "0.0.0.0/0"
-)
-
-type IPNetSet map[string]*net.IPNet
-
-func ParseIPNetSet(specs []string) (IPNetSet, error) {
-	ipnetset := make(IPNetSet)
-	for _, spec := range specs {
-		spec = strings.TrimSpace(spec)
-		_, ipnet, err := net.ParseCIDR(spec)
-		if err != nil {
-			return nil, err
-		}
-		k := ipnet.String() // In case of normalization
-		ipnetset[k] = ipnet
-	}
-	return ipnetset, nil
-}
-
-// StringSlice returns a []string with the String representation of each element in the set.
-// Order is undefined.
-func (s IPNetSet) StringSlice() []string {
-	a := make([]string, 0, len(s))
-	for k := range s {
-		a = append(a, k)
-	}
-	return a
-}
-
-// Equal checks if two IPNetSets are equal (ignoring order)
-func (l IPNetSet) Equal(r IPNetSet) bool {
-	if len(l) != len(r) {
-		return false
-	}
-
-	for k := range l {
-		_, found := r[k]
-		if !found {
-			return false
-		}
-	}
-	return true
-}
-
-// Len returns the size of the set.
-func (s IPNetSet) Len() int {
-	return len(s)
-}
-
-// GetSourceRangeAnnotations verifies and parses the LBAnnotationAllowSourceRange annotation from a service,
-// extracting the source ranges to allow, and if not present returns a default (allow-all) value.
-func GetSourceRangeAnnotations(annotation map[string]string) (IPNetSet, error) {
-	val := annotation[LBAnnotationAllowSourceRange]
-	val = strings.TrimSpace(val)
-	if val == "" {
-		val = defaultLBSourceRange
-	}
-	specs := strings.Split(val, ",")
-	ipnets, err := ParseIPNetSet(specs)
-	if err != nil {
-		return nil, fmt.Errorf("Service annotation %s:%s is not valid. Expecting a comma-separated list of source IP ranges. For example, 10.0.0.0/24,192.168.2.0/24", LBAnnotationAllowSourceRange, val)
-	}
-	return ipnets, nil
-}
-
-// IsAllowAll checks whether the IPNetSet contains the default allow-all policy
-func IsAllowAll(ipnets IPNetSet) bool {
-	for _, s := range ipnets.StringSlice() {
-		if s == "0.0.0.0/0" {
-			return true
-		}
-	}
-	return false
-}

pkg/util/net/sets/README.md

@@ -0,0 +1,17 @@
+This package contains hand-coded set implementations that should be similar to
+the autogenerated ones in `pkg/util/sets`.
+
+We can't simply use net.IPNet as a map-key in Go (because it contains a
+`[]byte`).
+
+We could use the same workaround we use here (a string representation as the
+key) to autogenerate sets.  If we do that, or decide on an alternate approach,
+we should replace the implementations in this package with the autogenerated
+versions.
+
+It is expected that callers will alias this import as `netsets`
+i.e. `import netsets "k8s.io/kubernetes/pkg/util/net/sets"`
+
+
+
+[![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/pkg/util/net/sets/README.md?pixel)]()

pkg/util/net/sets/ipnet.go

@@ -0,0 +1,119 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sets
+
+import (
+	"net"
+	"strings"
+)
+
+type IPNet map[string]*net.IPNet
+
+func ParseIPNets(specs ...string) (IPNet, error) {
+	ipnetset := make(IPNet)
+	for _, spec := range specs {
+		spec = strings.TrimSpace(spec)
+		_, ipnet, err := net.ParseCIDR(spec)
+		if err != nil {
+			return nil, err
+		}
+		k := ipnet.String() // In case of normalization
+		ipnetset[k] = ipnet
+	}
+	return ipnetset, nil
+}
+
+// Insert adds items to the set.
+func (s IPNet) Insert(items ...*net.IPNet) {
+	for _, item := range items {
+		s[item.String()] = item
+	}
+}
+
+// Delete removes all items from the set.
+func (s IPNet) Delete(items ...*net.IPNet) {
+	for _, item := range items {
+		delete(s, item.String())
+	}
+}
+
+// Has returns true if and only if item is contained in the set.
+func (s IPNet) Has(item *net.IPNet) bool {
+	_, contained := s[item.String()]
+	return contained
+}
+
+// HasAll returns true if and only if all items are contained in the set.
+func (s IPNet) HasAll(items ...*net.IPNet) bool {
+	for _, item := range items {
+		if !s.Has(item) {
+			return false
+		}
+	}
+	return true
+}
+
+// Difference returns a set of objects that are not in s2
+// For example:
+// s1 = {a1, a2, a3}
+// s2 = {a1, a2, a4, a5}
+// s1.Difference(s2) = {a3}
+// s2.Difference(s1) = {a4, a5}
+func (s IPNet) Difference(s2 IPNet) IPNet {
+	result := make(IPNet)
+	for k, i := range s {
+		_, found := s2[k]
+		if found {
+			continue
+		}
+		result[k] = i
+	}
+	return result
+}
+
+// StringSlice returns a []string with the String representation of each element in the set.
+// Order is undefined.
+func (s IPNet) StringSlice() []string {
+	a := make([]string, 0, len(s))
+	for k := range s {
+		a = append(a, k)
+	}
+	return a
+}
+
+// IsSuperset returns true if and only if s1 is a superset of s2.
+func (s1 IPNet) IsSuperset(s2 IPNet) bool {
+	for k := range s2 {
+		_, found := s1[k]
+		if !found {
+			return false
+		}
+	}
+	return true
+}
+
+// Equal returns true if and only if s1 is equal (as a set) to s2.
+// Two sets are equal if their membership is identical.
+// (In practice, this means same elements, order doesn't matter)
+func (s1 IPNet) Equal(s2 IPNet) bool {
+	return len(s1) == len(s2) && s1.IsSuperset(s2)
+}
+
+// Len returns the size of the set.
+func (s IPNet) Len() int {
+	return len(s)
+}

pkg/util/net/sets/ipnet_test.go

@@ -0,0 +1,155 @@
+/*
+Copyright 2014 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sets
+
+import (
+	"net"
+	"reflect"
+	"sort"
+	"testing"
+)
+
+func parseIPNet(s string) *net.IPNet {
+	_, net, err := net.ParseCIDR(s)
+	if err != nil {
+		panic(err)
+	}
+	return net
+}
+
+func TestIPNets(t *testing.T) {
+	s := IPNet{}
+	s2 := IPNet{}
+	if len(s) != 0 {
+		t.Errorf("Expected len=0: %d", len(s))
+	}
+	a := parseIPNet("1.0.0.0/8")
+	b := parseIPNet("2.0.0.0/8")
+	c := parseIPNet("3.0.0.0/8")
+	d := parseIPNet("4.0.0.0/8")
+
+	s.Insert(a, b)
+	if len(s) != 2 {
+		t.Errorf("Expected len=2: %d", len(s))
+	}
+	s.Insert(c)
+	if s.Has(d) {
+		t.Errorf("Unexpected contents: %#v", s)
+	}
+	if !s.Has(a) {
+		t.Errorf("Missing contents: %#v", s)
+	}
+	s.Delete(a)
+	if s.Has(a) {
+		t.Errorf("Unexpected contents: %#v", s)
+	}
+	s.Insert(a)
+	if s.HasAll(a, b, d) {
+		t.Errorf("Unexpected contents: %#v", s)
+	}
+	if !s.HasAll(a, b) {
+		t.Errorf("Missing contents: %#v", s)
+	}
+	s2.Insert(a, b, d)
+	if s.IsSuperset(s2) {
+		t.Errorf("Unexpected contents: %#v", s)
+	}
+	s2.Delete(d)
+	if !s.IsSuperset(s2) {
+		t.Errorf("Missing contents: %#v", s)
+	}
+}
+
+func TestIPNetSetDeleteMultiples(t *testing.T) {
+	s := IPNet{}
+	a := parseIPNet("1.0.0.0/8")
+	b := parseIPNet("2.0.0.0/8")
+	c := parseIPNet("3.0.0.0/8")
+
+	s.Insert(a, b, c)
+	if len(s) != 3 {
+		t.Errorf("Expected len=3: %d", len(s))
+	}
+
+	s.Delete(a, c)
+	if len(s) != 1 {
+		t.Errorf("Expected len=1: %d", len(s))
+	}
+	if s.Has(a) {
+		t.Errorf("Unexpected contents: %#v", s)
+	}
+	if s.Has(c) {
+		t.Errorf("Unexpected contents: %#v", s)
+	}
+	if !s.Has(b) {
+		t.Errorf("Missing contents: %#v", s)
+	}
+}
+
+func TestNewIPSet(t *testing.T) {
+	s, err := ParseIPNets("1.0.0.0/8", "2.0.0.0/8", "3.0.0.0/8")
+	if err != nil {
+		t.Errorf("error parsing IPNets: %v", err)
+	}
+	if len(s) != 3 {
+		t.Errorf("Expected len=3: %d", len(s))
+	}
+	a := parseIPNet("1.0.0.0/8")
+	b := parseIPNet("2.0.0.0/8")
+	c := parseIPNet("3.0.0.0/8")
+
+	if !s.Has(a) || !s.Has(b) || !s.Has(c) {
+		t.Errorf("Unexpected contents: %#v", s)
+	}
+}
+
+func TestIPNetSetDifference(t *testing.T) {
+	l, err := ParseIPNets("1.0.0.0/8", "2.0.0.0/8", "3.0.0.0/8")
+	if err != nil {
+		t.Errorf("error parsing IPNets: %v", err)
+	}
+	r, err := ParseIPNets("1.0.0.0/8", "2.0.0.0/8", "4.0.0.0/8", "5.0.0.0/8")
+	if err != nil {
+		t.Errorf("error parsing IPNets: %v", err)
+	}
+	c := l.Difference(r)
+	d := r.Difference(l)
+	if len(c) != 1 {
+		t.Errorf("Expected len=1: %d", len(c))
+	}
+	if !c.Has(parseIPNet("3.0.0.0/8")) {
+		t.Errorf("Unexpected contents: %#v", c)
+	}
+	if len(d) != 2 {
+		t.Errorf("Expected len=2: %d", len(d))
+	}
+	if !d.Has(parseIPNet("4.0.0.0/8")) || !d.Has(parseIPNet("5.0.0.0/8")) {
+		t.Errorf("Unexpected contents: %#v", d)
+	}
+}
+
+func TestIPNetSetList(t *testing.T) {
+	s, err := ParseIPNets("3.0.0.0/8", "1.0.0.0/8", "2.0.0.0/8")
+	if err != nil {
+		t.Errorf("error parsing IPNets: %v", err)
+	}
+	l := s.StringSlice()
+	sort.Strings(l)
+	if !reflect.DeepEqual(l, []string{"1.0.0.0/8", "2.0.0.0/8", "3.0.0.0/8"}) {
+		t.Errorf("List gave unexpected result: %#v", l)
+	}
+}