1 files changed, 58 insertions, 0 deletions
diff --git a/vendor/k8s.io/kubernetes/pkg/proxy/util/conntrack.go b/vendor/k8s.io/kubernetes/pkg/proxy/util/conntrack.go
new file mode 100644
index 000000000..436045ecb
--- /dev/null
+++ b/vendor/k8s.io/kubernetes/pkg/proxy/util/conntrack.go
@@ -0,0 +1,58 @@
+/*
+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 util
+
+import (
+	"fmt"
+	"strings"
+
+	"k8s.io/kubernetes/pkg/util/exec"
+
+	"github.com/golang/glog"
+)
+
+// Utilities for dealing with conntrack
+
+const noConnectionToDelete = "0 flow entries have been deleted"
+
+// DeleteServiceConnection uses the conntrack tool to delete the conntrack entries
+// for the UDP connections specified by the given service IPs
+func DeleteServiceConnections(execer exec.Interface, svcIPs []string) {
+	for _, ip := range svcIPs {
+		glog.V(2).Infof("Deleting connection tracking state for service IP %s", ip)
+		err := ExecConntrackTool(execer, "-D", "--orig-dst", ip, "-p", "udp")
+		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.
+			glog.Errorf("conntrack returned error: %v", err)
+		}
+	}
+}
+
+// ExecConntrackTool executes the conntrack tool using the given parameters
+func ExecConntrackTool(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
+}