route controller + azure v6 routes

cmd/cloud-controller-manager/app/core.go

@@ -21,6 +21,7 @@ limitations under the License.
 package app
 
 import (
+	"fmt"
 	"net"
 	"net/http"
 	"strings"
@@ -31,6 +32,10 @@ import (
 	cloudcontrollers "k8s.io/kubernetes/pkg/controller/cloud"
 	routecontroller "k8s.io/kubernetes/pkg/controller/route"
 	servicecontroller "k8s.io/kubernetes/pkg/controller/service"
+	netutils "k8s.io/utils/net"
+
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	kubefeatures "k8s.io/kubernetes/pkg/features"
 )
 
 func startCloudNodeController(ctx *cloudcontrollerconfig.CompletedConfig, cloud cloudprovider.Interface, stopCh <-chan struct{}) (http.Handler, bool, error) {
@@ -98,13 +103,26 @@ func startRouteController(ctx *cloudcontrollerconfig.CompletedConfig, cloud clou
 		klog.Warning("configure-cloud-routes is set, but cloud provider does not support routes. Will not configure cloud provider routes.")
 		return nil, false, nil
 	}
-	var clusterCIDR *net.IPNet
-	var err error
-	if len(strings.TrimSpace(ctx.ComponentConfig.KubeCloudShared.ClusterCIDR)) != 0 {
-		_, clusterCIDR, err = net.ParseCIDR(ctx.ComponentConfig.KubeCloudShared.ClusterCIDR)
-		if err != nil {
-			klog.Warningf("Unsuccessful parsing of cluster CIDR %v: %v", ctx.ComponentConfig.KubeCloudShared.ClusterCIDR, err)
-		}
+
+	// failure: bad cidrs in config
+	clusterCIDRs, dualStack, err := processCIDRs(ctx.ComponentConfig.KubeCloudShared.ClusterCIDR)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// failure: more than one cidr and dual stack is not enabled
+	if len(clusterCIDRs) > 1 && !utilfeature.DefaultFeatureGate.Enabled(kubefeatures.IPv6DualStack) {
+		return nil, false, fmt.Errorf("len of ClusterCIDRs==%v and dualstack feature is not enabled", len(clusterCIDRs))
+	}
+
+	// failure: more than one cidr but they are not configured as dual stack
+	if len(clusterCIDRs) > 1 && !dualStack {
+		return nil, false, fmt.Errorf("len of ClusterCIDRs==%v and they are not configured as dual stack (at least one from each IPFamily", len(clusterCIDRs))
+	}
+
+	// failure: more than cidrs is not allowed even with dual stack
+	if len(clusterCIDRs) > 2 {
+		return nil, false, fmt.Errorf("length of clusterCIDRs is:%v more than max allowed of 2", len(clusterCIDRs))
 	}
 
 	routeController := routecontroller.New(
@@ -112,9 +130,28 @@ func startRouteController(ctx *cloudcontrollerconfig.CompletedConfig, cloud clou
 		ctx.ClientBuilder.ClientOrDie("route-controller"),
 		ctx.SharedInformers.Core().V1().Nodes(),
 		ctx.ComponentConfig.KubeCloudShared.ClusterName,
-		clusterCIDR,
+		clusterCIDRs,
 	)
 	go routeController.Run(stopCh, ctx.ComponentConfig.KubeCloudShared.RouteReconciliationPeriod.Duration)
 
 	return nil, true, nil
 }
+
+// processCIDRs is a helper function that works on a comma separated cidrs and returns
+// a list of typed cidrs
+// a flag if cidrs represents a dual stack
+// error if failed to parse any of the cidrs
+func processCIDRs(cidrsList string) ([]*net.IPNet, bool, error) {
+	cidrsSplit := strings.Split(strings.TrimSpace(cidrsList), ",")
+
+	cidrs, err := netutils.ParseCIDRs(cidrsSplit)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// if cidrs has an error then the previous call will fail
+	// safe to ignore error checking on next call
+	dualstack, _ := netutils.IsDualStackCIDRs(cidrs)
+
+	return cidrs, dualstack, nil
+}