create netwowrk interface util

pkg/proxy/util/utils.go

@@ -17,15 +17,32 @@ limitations under the License.
 package util
 
 import (
+	"fmt"
 	"net"
 
 	"k8s.io/apimachinery/pkg/types"
+	utilnet "k8s.io/apimachinery/pkg/util/net"
+	"k8s.io/apimachinery/pkg/util/sets"
 	api "k8s.io/kubernetes/pkg/apis/core"
 	"k8s.io/kubernetes/pkg/apis/core/helper"
+	"k8s.io/kubernetes/pkg/proxy/apis/kubeproxyconfig"
+	"k8s.io/kubernetes/pkg/util/conntrack"
 
 	"github.com/golang/glog"
 )
 
+const (
+	IPv4ZeroCIDR = "0.0.0.0/0"
+	IPv6ZeroCIDR = "::/0"
+)
+
+func IsZeroCIDR(cidr string) bool {
+	if cidr == IPv4ZeroCIDR || cidr == IPv6ZeroCIDR {
+		return true
+	}
+	return false
+}
+
 func IsLocalIP(ip string) (bool, error) {
 	addrs, err := net.InterfaceAddrs()
 	if err != nil {
@@ -56,3 +73,70 @@ func ShouldSkipService(svcName types.NamespacedName, service *api.Service) bool
 	}
 	return false
 }
+
+// GetNodeAddresses list all match node IP addresses based on given cidr list.  Inject NetworkInterface for test purpose.
+// We expect the cidr list passed in is already validated.
+// Given `default-route`, it will the IP of host interface having default route.
+// Given an empty input `[]`, it will return `0.0.0.0/0` and `::/0` directly.
+func GetNodeAddresses(cidrs []string, nw NetworkInterface) (sets.String, error) {
+	uniqueAddressList := sets.NewString()
+	if len(cidrs) == 0 {
+		uniqueAddressList.Insert(IPv4ZeroCIDR)
+		uniqueAddressList.Insert(IPv6ZeroCIDR)
+		return uniqueAddressList, nil
+	}
+	// First round of iteration to pick out `0.0.0.0/0` or `::/0` for the sake of excluding non-zero IPs.
+	for _, cidr := range cidrs {
+		if IsZeroCIDR(cidr) {
+			uniqueAddressList.Insert(cidr)
+		}
+	}
+	// Second round of iteration to parse IPs based on cidr.
+	for _, cidr := range cidrs {
+		if IsZeroCIDR(cidr) {
+			continue
+		}
+		if cidr == string(kubeproxyconfig.DefaultRoute) {
+			hostIP, err := utilnet.ChooseHostInterface()
+			if err != nil {
+				return nil, fmt.Errorf("error selecting a host interface having default route, error: %v", err)
+			}
+			if conntrack.IsIPv6(hostIP) && !uniqueAddressList.Has(IPv6ZeroCIDR) {
+				uniqueAddressList.Insert(hostIP.String())
+			}
+			if !conntrack.IsIPv6(hostIP) && !uniqueAddressList.Has(IPv4ZeroCIDR) {
+				uniqueAddressList.Insert(hostIP.String())
+			}
+			continue
+		}
+		_, ipNet, _ := net.ParseCIDR(cidr)
+		itfs, err := nw.Interfaces()
+		if err != nil {
+			return nil, fmt.Errorf("error listing all interfaces from host, error: %v", err)
+		}
+		for _, itf := range itfs {
+			addrs, err := nw.Addrs(&itf)
+			if err != nil {
+				return nil, fmt.Errorf("error getting address from interface %s, error: %v", itf.Name, err)
+			}
+			for _, addr := range addrs {
+				if addr == nil {
+					continue
+				}
+				ip, _, err := net.ParseCIDR(addr.String())
+				if err != nil {
+					return nil, fmt.Errorf("error parsing CIDR for interface %s, error: %v", itf.Name, err)
+				}
+				if ipNet.Contains(ip) {
+					if conntrack.IsIPv6(ip) && !uniqueAddressList.Has(IPv6ZeroCIDR) {
+						uniqueAddressList.Insert(ip.String())
+					}
+					if !conntrack.IsIPv6(ip) && !uniqueAddressList.Has(IPv4ZeroCIDR) {
+						uniqueAddressList.Insert(ip.String())
+					}
+				}
+			}
+		}
+	}
+	return uniqueAddressList, nil
+}