Script for setting up linux namespaces

scripts/tools/linux_ip_namespace_setup.sh

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+#!/usr/bin/env bash
+#
+#
+#    Copyright (c) 2021 Project CHIP 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.
+#
+#
+#    Description:
+#      This is a utility script that can be used by developers to do
+#    simulate a device and controller on the same linux machine. This
+#    script is not intended to be used in a testing framework as-is
+#    because it requires root access to set up network namespaces.
+#
+#    To use this script, compile the required device example, and
+#    run inside the namespace using
+#    sudo <path>/linux_ip_namespace_setup.sh -r <path_to_app>
+#
+#    The controller can then be started in a new terminal and will
+#    be able to communicate with the application as if it were on
+#    a separate network.
+#
+
+NAMESPACE="MatterTester"
+HOST_SIDE_IF_NAME="heth0"
+NAMESPACE_SIDE_IF_NAME="neth0"
+BRIDGE_NAME="nbridge"
+BRIDGE_ADDR="192.168.4.50"
+NAMESPACE_ADDR="192.168.4.45"
+HOST_IPV6_ADDR=fc00::1
+BRIDGE_IPV6_ADDR=fc00::b
+NAMESPACE_IPV6_ADDR=fc00::a
+
+function run_setup() {
+    # Create namespace.
+    ip netns add "$NAMESPACE"
+
+    # Create two virtual interfaces and link them - one on host side, one on namespace side.
+    ip link add "$HOST_SIDE_IF_NAME" type veth peer name "$NAMESPACE_SIDE_IF_NAME"
+
+    # Give the host a known IPv6 addr and set the host side up
+    ip -6 addr add "$HOST_IPV6_ADDR"/64 dev "$HOST_SIDE_IF_NAME"
+    ip link set "$HOST_SIDE_IF_NAME" up
+
+    # Associate namespace IF with the namespace
+    ip link set "$NAMESPACE_SIDE_IF_NAME" netns "$NAMESPACE"
+
+    # Give the namespace IF an address (something nothing else is using) and set it up
+    echo "Adding address for namespace IF"
+    ip netns exec "$NAMESPACE" ip -6 addr add "$NAMESPACE_IPV6_ADDR"/64 dev "$NAMESPACE_SIDE_IF_NAME"
+    ip netns exec "$NAMESPACE" ip link set dev "$NAMESPACE_SIDE_IF_NAME" up
+
+    # Add a route to the namespace to go through the bridge
+    echo "Setting routes for namespace"
+    ip netns exec "$NAMESPACE" ip -6 route add default dev "$NAMESPACE_SIDE_IF_NAME"
+
+    echo "Setup complete."
+}
+
+function run_add_ipv4() {
+    # Give the namespace an IPv4 address
+    ip netns exec "$NAMESPACE" ip addr add "$NAMESPACE_ADDR"/24 dev "$NAMESPACE_SIDE_IF_NAME"
+
+    # Add a bridge, give it an address (something nothing else is using)
+    echo "Setting up bridge"
+    ip link add name "$BRIDGE_NAME" type bridge
+    ip -6 addr add "$BRIDGE_IPV6_ADDR"/64 dev "$BRIDGE_NAME"
+    ip addr add "$BRIDGE_ADDR"/24 brd + dev "$BRIDGE_NAME"
+
+    # For ipv6 and ipv4 to work together, need the bridge to ignore the ipv6 packets (DROP here means don't bridge)
+    ebtables-legacy -t broute -A BROUTING -p ipv6 -j DROP -i "$HOST_SIDE_IF_NAME"
+    ip link set "$BRIDGE_NAME" up
+
+    # Connect the host side to the bridge, so now we have bridge <-> host_side_if <-> namespace_if
+    echo "Connecting host virtual IF to bridge"
+    ip link set "$HOST_SIDE_IF_NAME" master "$BRIDGE_NAME"
+
+    #ip netns exec ${NAMESPACE} ip route add default via ${BRIDGE_ADDR} dev ${NAMESPACE_SIDE_IF_NAME}
+}
+
+function run_cmd() {
+    # Start the app in the namespace
+    echo "Running $1 in namespace."
+    ip netns exec "$NAMESPACE" "$1"
+}
+
+function run_cleanup() {
+    # Deleting the namespace will remove the namespace and peer'd interfaces to
+    have_ebtables_legacy=$1
+    ip netns delete "$NAMESPACE"
+    if ifconfig | grep "$BRIDGE_NAME"; then
+        if [ "$have_ebtables_legacy" = true ]; then
+            # Just try to drop the additional rule - it references our interface
+            # so if it's there, we added it.
+            ebtables-legacy -t broute -D BROUTING -p ipv6 -j DROP -i "$HOST_SIDE_IF_NAME" >/dev/null
+        fi
+        ip link delete dev "$BRIDGE_NAME" type bridge
+    fi
+}
+
+function help() {
+    echo "Usage: $file_name [ options ... ]"
+    echo ""
+
+    echo "This script is used to set up linux namespaces for Matter device testing"
+    echo "between a controller and device on the same linux machine."
+    echo ""
+    echo "To use this script, run the device code in a namespace using the -r command"
+    echo "and a controller in a seperate terminal to simulate two devices communicating"
+    echo "across a network."
+    echo "Example:"
+    echo "--------"
+    echo "Terminal 1:"
+    echo "sudo <path>/$file_name -r <path>/<application_name>"
+    echo ""
+    echo "Terminal 2:"
+    echo "<path>/chip-device-ctrl"
+    echo ""
+    echo "This script requires sudo for setup and requires access to ebtables-legacy"
+    echo "to set up dual ipv4/ipv6 namespaces. Defaults to ipv6 only."
+    echo ""
+
+    echo "Options:
+  -h, --help                Display this information.
+  -s, --setup               Setup an IP namespace. Will run cleanup if namespace exists.
+  -4, --ipv4                Add ipv4 support.
+  -r, --run filename        Run file in the namespace. Will setup namespace if required.
+  -c, --cleanup             Delete namespace and routes
+"
+}
+
+declare setup=false
+declare filename=""
+declare run=false
+declare cleanup=false
+declare ipv4=false
+
+file_name=${0##*/}
+
+while (($#)); do
+    case $1 in
+        --help | -h)
+            help
+            exit 1
+            ;;
+        --setup | -s)
+            setup=true
+            ;;
+        --run | -r)
+            run=true
+            filename=$2
+            shift
+            ;;
+        --cleanup | -c)
+            cleanup=true
+            ;;
+        --ipv4 | -4)
+            ipv4=true
+            ;;
+        -*)
+            help
+            echo "Unknown Option \"$1\""
+            exit 1
+            ;;
+    esac
+    shift
+done
+
+if [[ $EUID -ne 0 ]]; then
+    echo "You must run this script with superuser privileges."
+    exit 1
+fi
+
+if ifconfig | grep "$HOST_SIDE_IF_NAME"; then
+    issetup=true
+else
+    issetup=false
+fi
+
+if [ "$setup" = false ] && [ "$run" = false ] && [ "$cleanup" = false ]; then
+    echo "Must specify one or more of -s, -r, -c."
+    exit 1
+fi
+
+if command -v ebtables-legacy >/dev/null; then
+    have_ebtables_legacy=true
+else
+    have_ebtables_legacy=false
+fi
+
+if [ "$ipv4" = true ] && [ "$have_ebtables_legacy" = false ]; then
+    echo "To set up namespaces with ipv4/ipv6 connectivity, ebtables-legacy"
+    echo "is required. For example, to install on machines using APT:"
+    echo "sudo apt-get install ebtables"
+    exit 1
+fi
+
+if [ "$run" = true ]; then
+    if [ "$issetup" = false ]; then
+        setup=true
+    fi
+fi
+
+if [ "$setup" = true ]; then
+    if [ "$issetup" = true ]; then
+        cleanup=true
+    fi
+fi
+
+if [ "$cleanup" = true ]; then
+    run_cleanup "$have_ebtables_legacy"
+fi
+
+if [ "$setup" = true ]; then
+    run_setup
+    if [ "$ipv4" = true ]; then
+        run_add_ipv4
+    fi
+fi
+
+if [ "$run" = true ]; then
+    run_cmd "$filename"
+fi