fix IPV6 judgement bug and add UTs

pkg/proxy/iptables/proxier.go

@@ -1343,7 +1343,7 @@ func (proxier *Proxier) syncProxyRules() {
 					// This is very low impact. The NodePort range is intentionally obscure, and unlikely to actually collide with real Services.
 					// This only affects UDP connections, which are not common.
 					// See issue: https://github.com/kubernetes/kubernetes/issues/49881
-					isIPv6 := svcInfo.clusterIP.To4() != nil
+					isIPv6 := utilproxy.IsIPv6(svcInfo.clusterIP)
 					err := utilproxy.ClearUDPConntrackForPort(proxier.exec, lp.Port, isIPv6)
 					if err != nil {
 						glog.Errorf("Failed to clear udp conntrack for port %d, error: %v", lp.Port, err)

pkg/proxy/ipvs/proxier.go

@@ -1154,7 +1154,7 @@ func (proxier *Proxier) syncProxyRules() {
 					continue
 				}
 				if lp.Protocol == "udp" {
-					isIPv6 := svcInfo.clusterIP.To4() != nil
+					isIPv6 := utilproxy.IsIPv6(svcInfo.clusterIP)
 					utilproxy.ClearUDPConntrackForPort(proxier.exec, lp.Port, isIPv6)
 				}
 				replacementPortsMap[lp] = socket

pkg/proxy/util/conntrack.go

@@ -29,11 +29,15 @@ import (
 
 const noConnectionToDelete = "0 flow entries have been deleted"
 
-func isIPv6(ip string) bool {
-	netIP := net.ParseIP(ip)
+func IsIPv6(netIP net.IP) bool {
 	return netIP != nil && netIP.To4() == nil
 }
 
+func IsIPv6String(ip string) bool {
+	netIP := net.ParseIP(ip)
+	return IsIPv6(netIP)
+}
+
 func parametersWithFamily(isIPv6 bool, parameters ...string) []string {
 	if isIPv6 {
 		parameters = append(parameters, "-f", "ipv6")
@@ -44,7 +48,7 @@ func parametersWithFamily(isIPv6 bool, parameters ...string) []string {
 // ClearUDPConntrackForIP uses the conntrack tool to delete the conntrack entries
 // for the UDP connections specified by the given service IP
 func ClearUDPConntrackForIP(execer exec.Interface, ip string) error {
-	parameters := parametersWithFamily(isIPv6(ip), "-D", "--orig-dst", ip, "-p", "udp")
+	parameters := parametersWithFamily(IsIPv6String(ip), "-D", "--orig-dst", ip, "-p", "udp")
 	err := ExecConntrackTool(execer, parameters...)
 	if err != nil && !strings.Contains(err.Error(), noConnectionToDelete) {
 		// TODO: Better handling for deletion failure. When failure occur, stale udp connection may not get flushed.
@@ -89,7 +93,7 @@ func ClearUDPConntrackForPort(execer exec.Interface, port int, isIPv6 bool) erro
 // ClearUDPConntrackForPeers uses the conntrack tool to delete the conntrack entries
 // for the UDP connections specified by the {origin, dest} IP pair.
 func ClearUDPConntrackForPeers(execer exec.Interface, origin, dest string) error {
-	parameters := parametersWithFamily(isIPv6(origin), "-D", "--orig-dst", origin, "--dst-nat", dest, "-p", "udp")
+	parameters := parametersWithFamily(IsIPv6String(origin), "-D", "--orig-dst", origin, "--dst-nat", dest, "-p", "udp")
 	err := ExecConntrackTool(execer, parameters...)
 	if err != nil && !strings.Contains(err.Error(), noConnectionToDelete) {
 		// TODO: Better handling for deletion failure. When failure occur, stale udp connection may not get flushed.

pkg/proxy/util/conntrack_test.go

@@ -18,6 +18,7 @@ package util
 
 import (
 	"fmt"
+	"net"
 	"strings"
 	"testing"
 
@@ -117,7 +118,7 @@ func TestClearUDPConntrackForIP(t *testing.T) {
 		if err := ClearUDPConntrackForIP(&fexec, tc.ip); err != nil {
 			t.Errorf("%s test case:, Unexpected error: %v", tc.name, err)
 		}
-		expectCommand := fmt.Sprintf("conntrack -D --orig-dst %s -p udp", tc.ip) + familyParamStr(isIPv6(tc.ip))
+		expectCommand := fmt.Sprintf("conntrack -D --orig-dst %s -p udp", tc.ip) + familyParamStr(IsIPv6String(tc.ip))
 		execCommand := strings.Join(fcmd.CombinedOutputLog[svcCount], " ")
 		if expectCommand != execCommand {
 			t.Errorf("%s test case: Expect command: %s, but executed %s", tc.name, expectCommand, execCommand)
@@ -221,7 +222,7 @@ func TestDeleteUDPConnections(t *testing.T) {
 		if err != nil {
 			t.Errorf("%s test case: unexpected error: %v", tc.name, err)
 		}
-		expectCommand := fmt.Sprintf("conntrack -D --orig-dst %s --dst-nat %s -p udp", tc.origin, tc.dest) + familyParamStr(isIPv6(tc.origin))
+		expectCommand := fmt.Sprintf("conntrack -D --orig-dst %s --dst-nat %s -p udp", tc.origin, tc.dest) + familyParamStr(IsIPv6String(tc.origin))
 		execCommand := strings.Join(fcmd.CombinedOutputLog[i], " ")
 		if expectCommand != execCommand {
 			t.Errorf("%s test case: Expect command: %s, but executed %s", tc.name, expectCommand, execCommand)
@@ -232,3 +233,99 @@ func TestDeleteUDPConnections(t *testing.T) {
 		t.Errorf("Expect command executed %d times, but got %d", svcCount, fexec.CommandCalls)
 	}
 }
+
+func TestIsIPv6String(t *testing.T) {
+	testCases := []struct {
+		ip         string
+		expectIPv6 bool
+	}{
+		{
+			ip:         "127.0.0.1",
+			expectIPv6: false,
+		},
+		{
+			ip:         "192.168.0.0",
+			expectIPv6: false,
+		},
+		{
+			ip:         "1.2.3.4",
+			expectIPv6: false,
+		},
+		{
+			ip:         "bad ip",
+			expectIPv6: false,
+		},
+		{
+			ip:         "::1",
+			expectIPv6: true,
+		},
+		{
+			ip:         "fd00::600d:f00d",
+			expectIPv6: true,
+		},
+		{
+			ip:         "2001:db8::5",
+			expectIPv6: true,
+		},
+	}
+	for i := range testCases {
+		isIPv6 := IsIPv6String(testCases[i].ip)
+		if isIPv6 != testCases[i].expectIPv6 {
+			t.Errorf("[%d] Expect ipv6 %v, got %v", i+1, testCases[i].expectIPv6, isIPv6)
+		}
+	}
+}
+
+func TestIsIPv6(t *testing.T) {
+	testCases := []struct {
+		ip         net.IP
+		expectIPv6 bool
+	}{
+		{
+			ip:         net.IPv4zero,
+			expectIPv6: false,
+		},
+		{
+			ip:         net.IPv4bcast,
+			expectIPv6: false,
+		},
+		{
+			ip:         net.ParseIP("127.0.0.1"),
+			expectIPv6: false,
+		},
+		{
+			ip:         net.ParseIP("10.20.40.40"),
+			expectIPv6: false,
+		},
+		{
+			ip:         net.ParseIP("172.17.3.0"),
+			expectIPv6: false,
+		},
+		{
+			ip:         nil,
+			expectIPv6: false,
+		},
+		{
+			ip:         net.IPv6loopback,
+			expectIPv6: true,
+		},
+		{
+			ip:         net.IPv6zero,
+			expectIPv6: true,
+		},
+		{
+			ip:         net.ParseIP("fd00::600d:f00d"),
+			expectIPv6: true,
+		},
+		{
+			ip:         net.ParseIP("2001:db8::5"),
+			expectIPv6: true,
+		},
+	}
+	for i := range testCases {
+		isIPv6 := IsIPv6(testCases[i].ip)
+		if isIPv6 != testCases[i].expectIPv6 {
+			t.Errorf("[%d] Expect ipv6 %v, got %v", i+1, testCases[i].expectIPv6, isIPv6)
+		}
+	}
+}