Add generated file

This PR adds generated files under pkg/client and vendor folder.

vendor/k8s.io/kubernetes/pkg/util/conntrack/conntrack.go

@@ -0,0 +1,109 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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 conntrack
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"k8s.io/api/core/v1"
+	utilnet "k8s.io/kubernetes/pkg/util/net"
+	"k8s.io/utils/exec"
+)
+
+// Utilities for dealing with conntrack
+
+// NoConnectionToDelete is the error string returned by conntrack when no matching connections are found
+const NoConnectionToDelete = "0 flow entries have been deleted"
+
+func protoStr(proto v1.Protocol) string {
+	return strings.ToLower(string(proto))
+}
+
+func parametersWithFamily(isIPv6 bool, parameters ...string) []string {
+	if isIPv6 {
+		parameters = append(parameters, "-f", "ipv6")
+	}
+	return parameters
+}
+
+// ClearEntriesForIP uses the conntrack tool to delete the conntrack entries
+// for the UDP connections specified by the given service IP
+func ClearEntriesForIP(execer exec.Interface, ip string, protocol v1.Protocol) error {
+	parameters := parametersWithFamily(utilnet.IsIPv6String(ip), "-D", "--orig-dst", ip, "-p", protoStr(protocol))
+	err := Exec(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.
+		// These stale udp connection will keep black hole traffic. Making this a best effort operation for now, since it
+		// is expensive to baby-sit all udp connections to kubernetes services.
+		return fmt.Errorf("error deleting connection tracking state for UDP service IP: %s, error: %v", ip, err)
+	}
+	return nil
+}
+
+// Exec executes the conntrack tool using the given parameters
+func Exec(execer exec.Interface, parameters ...string) error {
+	conntrackPath, err := execer.LookPath("conntrack")
+	if err != nil {
+		return fmt.Errorf("error looking for path of conntrack: %v", err)
+	}
+	output, err := execer.Command(conntrackPath, parameters...).CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("conntrack command returned: %q, error message: %s", string(output), err)
+	}
+	return nil
+}
+
+// Exists returns true if conntrack binary is installed.
+func Exists(execer exec.Interface) bool {
+	_, err := execer.LookPath("conntrack")
+	return err == nil
+}
+
+// ClearEntriesForPort uses the conntrack tool to delete the conntrack entries
+// for connections specified by the port.
+// When a packet arrives, it will not go through NAT table again, because it is not "the first" packet.
+// The solution is clearing the conntrack. Known issues:
+// https://github.com/docker/docker/issues/8795
+// https://github.com/kubernetes/kubernetes/issues/31983
+func ClearEntriesForPort(execer exec.Interface, port int, isIPv6 bool, protocol v1.Protocol) error {
+	if port <= 0 {
+		return fmt.Errorf("Wrong port number. The port number must be greater than zero")
+	}
+	parameters := parametersWithFamily(isIPv6, "-D", "-p", protoStr(protocol), "--dport", strconv.Itoa(port))
+	err := Exec(execer, parameters...)
+	if err != nil && !strings.Contains(err.Error(), NoConnectionToDelete) {
+		return fmt.Errorf("error deleting conntrack entries for UDP port: %d, error: %v", port, err)
+	}
+	return nil
+}
+
+// ClearEntriesForNAT uses the conntrack tool to delete the conntrack entries
+// for connections specified by the {origin, dest} IP pair.
+func ClearEntriesForNAT(execer exec.Interface, origin, dest string, protocol v1.Protocol) error {
+	parameters := parametersWithFamily(utilnet.IsIPv6String(origin), "-D", "--orig-dst", origin, "--dst-nat", dest,
+		"-p", protoStr(protocol))
+	err := Exec(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.
+		// These stale udp connection will keep black hole traffic. Making this a best effort operation for now, since it
+		// is expensive to baby sit all udp connections to kubernetes services.
+		return fmt.Errorf("error deleting conntrack entries for UDP peer {%s, %s}, error: %v", origin, dest, err)
+	}
+	return nil
+}