added simple_nat example

examples/simple_nat/cleanup.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+
+# Copyright 2013-present Barefoot Networks, Inc.
+#
+# 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.
+
+if [[ $EUID -ne 0 ]]; then
+    echo "This script should be run using sudo or as the root user"
+    exit 1
+fi
+
+killall lt-simple_switch &> /dev/null
+mn -c &> /dev/null
+intf="cpu-veth-0"
+if ip link show $intf &> /dev/null; then
+  ip link delete $intf type veth
+fi