1 files changed, 80 insertions, 0 deletions
diff --git a/test/iptables/nat.go b/test/iptables/nat.go
new file mode 100644
index 000000000..b5c6f927e
--- /dev/null
+++ b/test/iptables/nat.go
@@ -0,0 +1,80 @@
+// Copyright 2020 The gVisor 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 iptables
+
+import (
+	"fmt"
+	"net"
+)
+
+const (
+	redirectPort = 42
+)
+
+func init() {
+	RegisterTestCase(NATRedirectUDPPort{})
+	RegisterTestCase(NATDropUDP{})
+}
+
+// NATRedirectUDPPort tests that packets are redirected to different port.
+type NATRedirectUDPPort struct{}
+
+// Name implements TestCase.Name.
+func (NATRedirectUDPPort) Name() string {
+	return "NATRedirectUDPPort"
+}
+
+// ContainerAction implements TestCase.ContainerAction.
+func (NATRedirectUDPPort) ContainerAction(ip net.IP) error {
+	if err := filterTable("-t", "nat", "-A", "PREROUTING", "-p", "udp", "-j", "REDIRECT", "--to-ports", fmt.Sprintf("%d", redirectPort)); err != nil {
+		return err
+	}
+
+	if err := listenUDP(redirectPort, sendloopDuration); err != nil {
+		return fmt.Errorf("packets on port %d should be allowed, but encountered an error: %v", redirectPort, err)
+	}
+	return nil
+}
+
+// LocalAction implements TestCase.LocalAction.
+func (NATRedirectUDPPort) LocalAction(ip net.IP) error {
+	return sendUDPLoop(ip, acceptPort, sendloopDuration)
+}
+
+// NATDropUDP tests that packets are not received in ports other than redirect port.
+type NATDropUDP struct{}
+
+// Name implements TestCase.Name.
+func (NATDropUDP) Name() string {
+	return "NATDropUDP"
+}
+
+// ContainerAction implements TestCase.ContainerAction.
+func (NATDropUDP) ContainerAction(ip net.IP) error {
+	if err := filterTable("-t", "nat", "-A", "PREROUTING", "-p", "udp", "-j", "REDIRECT", "--to-ports", fmt.Sprintf("%d", redirectPort)); err != nil {
+		return err
+	}
+
+	if err := listenUDP(acceptPort, sendloopDuration); err == nil {
+		return fmt.Errorf("packets on port %d should have been redirected to port %d", acceptPort, redirectPort)
+	}
+
+	return nil
+}
+
+// LocalAction implements TestCase.LocalAction.
+func (NATDropUDP) LocalAction(ip net.IP) error {
+	return sendUDPLoop(ip, acceptPort, sendloopDuration)
+}