Merge pull request #27 from ehlers/netem

Packer scripts for NETem

packer/NETem/NETem.json

@@ -0,0 +1,60 @@
+{
+    "variables": {
+        "tc_iso_url": "http://distro.ibiblio.org/tinycorelinux/6.x/x86/release/Core-6.4.iso",
+        "tc_iso_checksum": "c8e04e26de234e5528e6eac8ecb1bdda",
+        "vm_name": "NETem.qcow2",
+        "setup_script": "NETem.sh",
+        "upload_dir": "uploads",
+        "disk_size": "32"
+    },
+    "builders": [
+        {
+            "type": "qemu",
+            "iso_url": "{{user `tc_iso_url`}}",
+            "iso_checksum": "{{user `tc_iso_checksum`}}",
+            "iso_checksum_type": "md5",
+            "shutdown_command": "sudo poweroff",
+            "format": "qcow2",
+            "headless": false,
+            "ssh_username": "gns3",
+            "ssh_password": "gns3",
+            "accelerator": "none",
+            "vm_name": "{{user `vm_name`}}",
+            "disk_interface": "ide",
+            "disk_size": "{{user `disk_size`}}",
+            "net_device": "e1000",
+            "http_directory": "http",
+            "boot_wait": "5s",
+            "boot_command": [
+                "mc user=gns3<enter><wait10><wait10><wait10><wait10><wait10><wait10>",
+                "sudo passwd gns3<enter>gns3<enter>gns3<enter>",
+                "tce-load -wi openssh<enter><wait10>",
+                "cd /usr/local/etc/ssh; [ -f sshd_config.example ] && sudo cp -a sshd_config.example sshd_config; cd<enter>",
+                "sudo /usr/local/etc/init.d/openssh start<enter>"
+            ]
+        }
+    ],
+    "provisioners": [
+        {
+            "type": "shell",
+            "script": "scripts/hd-install.sh"
+        },
+        {
+            "type": "shell",
+            "script": "scripts/serial.sh"
+        },
+        {
+            "type": "file",
+            "source": "{{user `upload_dir`}}/",
+            "destination": "/tmp"
+        },
+        {
+            "type": "shell",
+            "script": "scripts/{{user `setup_script`}}"
+        },
+        {
+            "type": "shell",
+            "script": "scripts/post_setup.sh"
+        }
+    ]
+}

packer/NETem/scripts/NETem.sh

@@ -0,0 +1,112 @@
+set -e
+set -x
+
+# get TinyCore mirror
+. /etc/init.d/tc-functions
+getMirror
+
+# TCE directory back to ramdisk
+mv /etc/sysconfig/tcedir /etc/sysconfig/tcedir.hd
+ln -s /tmp/tce /etc/sysconfig/tcedir
+
+mkdir build
+cd build
+tce-load -wi squashfs-tools
+
+# create utf8-locale
+tce-load -wi getlocale
+sudo mkdir -p /usr/lib/locale
+sudo localedef -i en_US -c -f UTF-8 en_US.UTF-8
+sudo localedef -i en_US -c -f UTF-8 C.UTF-8
+sudo mkdir -p /tmp/utf8-locale/usr/lib/locale
+sudo cp -p /usr/lib/locale/* /tmp/utf8-locale/usr/lib/locale/
+mksquashfs /tmp/utf8-locale utf8-locale.tcz
+md5sum utf8-locale.tcz > utf8-locale.tcz.md5.txt
+
+# create python3dialog
+tce-load -wi python3-dev
+wget https://bootstrap.pypa.io/get-pip.py
+sudo python3 get-pip.py
+rm get-pip.py
+tce-load -wi dialog
+sudo LANG=C.UTF-8 pip3 install pythondialog
+sudo mkdir -p /tmp/python3dialog/usr/local/lib/python3.4/site-packages
+sudo cp -a /usr/local/lib/python3.4/site-packages/dialog* /tmp/python3dialog/usr/local/lib/python3.4/site-packages/
+sudo cp -a /usr/local/lib/python3.4/site-packages/pythondialog* /tmp/python3dialog/usr/local/lib/python3.4/site-packages/
+mksquashfs /tmp/python3dialog python3dialog.tcz
+md5sum python3dialog.tcz > python3dialog.tcz.md5.txt
+echo -e 'python3.tcz\ndialog.tcz' > python3dialog.tcz.dep
+
+# TCEDIR back to harddisk
+rm -f /etc/sysconfig/tcedir; mv /etc/sysconfig/tcedir.hd /etc/sysconfig/tcedir
+mkdir -p /etc/sysconfig/tcedir/optional
+chmod 775 /etc/sysconfig/tcedir/optional
+rm -f /usr/local/tce.installed/*
+
+# install utf8-locale
+cp -p utf8-locale.tcz* /etc/sysconfig/tcedir/optional/
+echo 'utf8-locale.tcz' >> /etc/sysconfig/tcedir/onboot.lst
+
+# install python3 without TK
+cp -p /tmp/tce/optional/python3.tcz /etc/sysconfig/tcedir/optional/
+cp -p /tmp/tce/optional/python3.tcz.md5.txt /etc/sysconfig/tcedir/optional/
+sed -e '/^tk/ d' /tmp/tce/optional/python3.tcz.dep > /etc/sysconfig/tcedir/optional/python3.tcz.dep
+echo 'python3.tcz' >> /etc/sysconfig/tcedir/onboot.lst
+for pkg in `cat /etc/sysconfig/tcedir/optional/python3.tcz.dep`; do tce-load -w $pkg; done
+
+# install python3dialog
+cp -p python3dialog.tcz* /etc/sysconfig/tcedir/optional/
+echo 'python3dialog.tcz' >> /etc/sysconfig/tcedir/onboot.lst
+tce-load -w dialog
+
+# additional linux networking modules
+KERNEL=`uname -r`
+tce-load -w net-bridging-$KERNEL
+echo "net-bridging-$KERNEL.tcz" >> /etc/sysconfig/tcedir/onboot.lst
+tce-load -w net-sched-$KERNEL
+echo "net-sched-$KERNEL.tcz" >> /etc/sysconfig/tcedir/onboot.lst
+
+# iproute2 without db library
+# Bug in TinyCore 6.x, which makes arpd non-working:
+# There is a mismatch of the library version between arpd and the db library.
+# Therefore loading the db library has no advantage, it uses only disk space.
+wget $MIRROR/iproute2.tcz
+wget $MIRROR/iproute2.tcz.md5.txt
+cp -p iproute2.tcz* /etc/sysconfig/tcedir/optional/
+echo 'iproute2.tcz' >> /etc/sysconfig/tcedir/onboot.lst
+
+# clean up build environment
+cd ..
+rm -r build
+
+# NETem menu system
+mv /tmp/netem-conf.py .
+chmod +x netem-conf.py
+
+# autologin on serial console
+sudo sed -i -e '/^tty1:/ s/^.*/tty1::respawn:\/sbin\/getty 38400 tty1/' -e '/^ttyS0:/ s/^.*/ttyS0::askfirst:\/sbin\/getty -nl \/sbin\/autologin 38400 ttyS0 xterm/' /etc/inittab
+sudo sed -i -e 's/tty1/`\/usr\/bin\/tty`/' /sbin/autologin
+echo 'sbin/autologin' >> /opt/.filetool.lst
+
+# autostart netem-conf
+sed -i -e '/^TERMTYPE/,$ d' .profile
+cat >> .profile << 'EOF'
+# autostart netem-conf only on local terminals
+TERMTYPE=`/usr/bin/tty`
+if [ "${TERMTYPE:5:3}" = "tty" ]; then
+	./netem-conf.py
+	rm -f /var/log/autologin
+fi
+EOF
+
+# disable automatic interface configuration with dhcp
+sudo sed -i -e '/label microcore/,/append / s/\(append .*\)/\1 nodhcp/' /mnt/sda1/boot/extlinux/extlinux.conf
+
+# set locale and configure network at startup
+sed -n -e '1,/^\/opt\/bootlocal/ p' /opt/bootsync.sh | head -n -1 > /tmp/bootsync.head
+sed -n -e '/^\/opt\/bootlocal/,$ p' /opt/bootsync.sh > /tmp/bootsync.tail
+cat /tmp/bootsync.head > /opt/bootsync.sh
+cat /tmp/boot_script >> /opt/bootsync.sh; echo >> /opt/bootsync.sh
+cat /tmp/bootsync.tail >> /opt/bootsync.sh
+
+# Done

packer/NETem/scripts/hd-install.sh

@@ -0,0 +1,43 @@
+# Install tinycore on harddisk
+
+set -x
+
+# format harddisk
+echo -e 'n\np\n1\n\n\na\n1\nw' | sudo fdisk -H16 -S32 /dev/sda
+sudo mkfs.ext2 /dev/sda1
+
+# copy system to harddisk
+sudo mkdir /mnt/sda1
+sudo mount /dev/sda1 /mnt/sda1
+sudo mount /mnt/sr0
+sudo cp -a /mnt/sr0/boot /mnt/sda1/
+sudo umount /mnt/sr0
+
+# modify bootloader config
+sudo mv /mnt/sda1/boot/isolinux /mnt/sda1/boot/extlinux
+cd /mnt/sda1/boot/extlinux
+sudo rm boot.cat isolinux.bin
+sudo mv isolinux.cfg extlinux.conf
+sudo sed -i -e '/append / s/$/ user=gns3/' -e 's/timeout .*/timeout 1/' extlinux.conf
+cd
+
+# make disk bootable
+tce-load -wi syslinux
+sudo sh -c 'cat /usr/local/share/syslinux/mbr.bin > /dev/sda'
+sudo /usr/local/sbin/extlinux --install /mnt/sda1/boot/extlinux
+
+# create extensions directory
+sudo mkdir /mnt/sda1/tce
+sudo chgrp staff /mnt/sda1/tce
+sudo chmod 775 /mnt/sda1/tce
+
+# change tcedir to harddisk
+mv /etc/sysconfig/tcedir /etc/sysconfig/tcedir.bak
+ln -s /mnt/sda1/tce /etc/sysconfig/tcedir
+rm -rf /usr/local/tce.installed/*
+
+# base system modifications
+sudo sed -i -e '/^\/opt\/bootlocal/ i' /opt/bootsync.sh
+echo -e "\nusername 'gns3', password 'gns3'\n" >> /etc/issue
+echo 'etc/issue' >> /opt/.filetool.lst
+echo 'etc/shadow' >> /opt/.filetool.lst

packer/NETem/scripts/post_setup.sh

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+# post-installation script
+set -x
+
+# save changes
+rm -f .ash_history
+filetool.sh -b sda1
+
+# write 0, not really necessary
+#sudo dd if=/dev/zero of=/mnt/sda1/zero ; sudo rm -f /mnt/sda1/zero

packer/NETem/scripts/serial.sh

@@ -0,0 +1,21 @@
+# Add serial console support
+
+set -x
+
+# Boot configuration
+# Serial interface is secondary console, the vga console remains main console
+# To change that, swap the two 'console=' boot parameter
+sudo sed -i -e '1 i serial 0 38400' -e '/label microcore/,/append / s/\(append .*\)/\1 console=ttyS0,38400 console=tty0/' /mnt/sda1/boot/extlinux/extlinux.conf
+
+# /etc/inittab
+sudo sed -i -e '/tty6/ a ttyS0::respawn:/sbin/getty 38400 ttyS0 xterm' /etc/inittab
+
+# /etc/securetty
+sudo sed -i -e 's/^# *ttyS0/ttyS0/' /etc/securetty
+
+# reload inittab on startup
+sudo sed -i -e '/^\/opt\/bootlocal/ i # reload inittab' -e '/^\/opt\/bootlocal/ i kill -HUP 1' -e '/^\/opt\/bootlocal/ i' /opt/bootsync.sh
+
+# add modified files to backup list
+echo 'etc/inittab' >> /opt/.filetool.lst
+echo 'etc/securetty' >> /opt/.filetool.lst

packer/NETem/uploads/boot_script

@@ -0,0 +1,26 @@
+. /etc/init.d/tc-functions
+
+# default LANG=C.UTF-8
+[ ! -f /etc/sysconfig/language ] || [ "`cat /etc/sysconfig/language`" = "LANG=C" ] && \
+	echo "LANG=C.UTF-8" > /etc/sysconfig/language
+
+# Configure network interfaces only when boot parameter "nodhcp" is used
+if grep -q -w nodhcp /proc/cmdline; then
+	echo -en "${BLUE}Configuring network interfaces... ${NORMAL}"
+
+	# This waits until all devices have registered
+	/sbin/udevadm settle --timeout=10
+
+	ip link add name br0 type bridge
+	ip link set dev eth0 promisc on
+	ip link set dev eth0 mtu 2000
+	ip link set dev eth0 up
+	ip link set dev eth0 master br0
+	ip link set dev eth1 promisc on
+	ip link set dev eth1 mtu 2000
+	ip link set dev eth1 up
+	ip link set dev eth1 master br0
+	ip link set dev br0 up
+
+	echo -e "${GREEN}Done.${NORMAL}"
+fi

packer/NETem/uploads/netem-conf.py

@@ -0,0 +1,397 @@
+#!/usr/bin/env python3
+#
+# netem-conf - configure NETem parameter
+#
+import copy
+import os
+import subprocess
+import json
+from dialog import Dialog
+
+# minimal config
+config = { 'eth0_to_eth1': {}, 'symmetric': True }
+
+# open dialog system
+d = Dialog(dialog="dialog", autowidgetsize=True)
+d.add_persistent_args(["--no-collapse"])
+
+
+# configure NETem parameter in linux
+def conf_netem(link, dev):
+    # remove current config
+    subprocess.call(['sudo', '-S', 'tc', 'qdisc', 'del', 'dev', dev, 'root'],
+                    stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL,
+                    stderr=subprocess.DEVNULL)
+
+    # base NETem command line
+    netem_cmd = ['sudo', '-S', 'tc', 'qdisc', 'add', 'dev', dev]
+
+    # configure bandwidth with htb
+    if config[link].get('bandwidth') is not None:
+        buffer = max(int(0.3*config[link]['bandwidth']+0.5), 1600)
+        bw_cmd =  ['sudo', '-S', 'tc', 'qdisc', 'add', 'dev', dev,
+                   'root', 'handle', '1:',
+                   'tbf', 'rate', str(config[link]['bandwidth'])+"kbit",
+                   'buffer', str(buffer), 'latency', '20ms']
+        proc = subprocess.Popen(bw_cmd, stdin=subprocess.DEVNULL,
+                          stdout=subprocess.DEVNULL, stderr=subprocess.PIPE)
+        out, err = proc.communicate()
+        if err:
+            err = err.decode('ascii').strip()
+            if err == "Password:":
+                err = "sudo needs password"
+            d.msgbox("Can't configure bandwidth !!!\n\n" + \
+                     " ".join(bw_cmd) + "\n\n" + str(err))
+            return False
+        netem_cmd += ['parent', '1:1', 'handle', '10']
+    else:
+        netem_cmd += ['root', 'handle', '1']
+
+    netem_cmd.append('netem')
+
+    # add delay to command line
+    if config[link].get('delay') is not None:
+        netem_cmd.append("delay")
+        netem_cmd.append(str(config[link]['delay']) + "ms")
+        if config[link].get('jitter') is not None:
+            netem_cmd.append(str(config[link]['jitter']) + "ms")
+
+    # add loss to command line
+    # see http://netgroup.uniroma2.it/TR/TR-loss-netem.pdf
+    if config[link].get('loss') is not None:
+        if config[link].get('loss_burst') is None:
+            p13 = config[link]['loss']
+            p31 = 100 - config[link]['loss']
+        else:
+            p13 = config[link]['loss'] / \
+                  (config[link]['loss_burst'] * (1 - config[link]['loss'] / 100))
+            p31 = 100 / config[link]['loss_burst']
+        netem_cmd.append("loss")
+        netem_cmd.append("gemodel")
+        netem_cmd.append(str(p13) + "%")
+        netem_cmd.append(str(p31) + "%")
+        netem_cmd.append("0")
+        netem_cmd.append("0")
+
+    # configure NETem parameter
+    proc = subprocess.Popen(netem_cmd, stdin=subprocess.DEVNULL,
+                            stdout=subprocess.DEVNULL, stderr=subprocess.PIPE)
+    out, err = proc.communicate()
+    if err:
+        err = err.decode('ascii').strip()
+        if err == "Password:":
+            err = "sudo needs password"
+        d.msgbox("Can't configure NETem !!!\n\n" + \
+                 " ".join(netem_cmd) + "\n\n" + str(err))
+        return False
+
+    return True
+
+
+# bandwidth configuration of a link
+def string_bandwidth(link):
+    if config[link].get('bandwidth') is None:
+        bw_text = "<No Limit>"
+    else:
+        bw_text = str(config[link]['bandwidth']) + " kBit/s"
+    return bw_text
+
+
+# delay configuration of a link
+def string_delay(link):
+    if config[link].get('delay') is None:
+        delay_text = "<None>"
+    else:
+        delay_text = str(config[link]['delay']) + " ms"
+        if config[link].get('jitter') is not None:
+            delay_text += ",  Jitter:  " + str(config[link]['jitter']) + " ms"
+    return delay_text
+
+
+# loss configuration of a link
+def string_loss(link):
+    if config[link].get('loss') is None:
+        loss_text = "<None>"
+    else:
+        loss_text = str(config[link]['loss']) + " %"
+        if config[link].get('loss_burst') is not None:
+            loss_text += ",  Burst:  " + str(config[link]['loss_burst'])
+    return loss_text
+
+
+# convert string to number
+def conv_num(string):
+    string = string.strip()
+    if string == "":
+        x = None
+    else:
+        try:
+            x = float(string)
+            if abs(x) < 1e9 and x == int(x):
+                x = int(x)
+        except ValueError:
+            raise ValueError("Invalid number: " + string)
+    return x
+
+
+# convert string to postitive number (or zero)
+def conv_num_positive(string):
+    x = conv_num(string)
+    if x is not None and x < 0:
+        raise ValueError("Negative number: " + string)
+    return x
+
+
+# convert string to number greater or equal one
+def conv_num_ge_one(string):
+    x = conv_num(string)
+    if x is not None and x < 1:
+        raise ValueError("Must be at least 1: " + string)
+    return x
+
+
+# convert string to percentage
+def conv_num_percent(string):
+    x = conv_num(string)
+    if x is not None and (x < 0 or x > 100):
+        raise ValueError("Percentage must be 0..100: " + string)
+    return x
+
+
+# link parameter for parsing
+# ( variable, label, unit, conversion_function, input_width )
+link_param_bandwidth = [
+    ( "bandwidth",  "Bandwidth",   "kBit/s", conv_num_positive, 10 ) ]
+link_param_delay = [
+    ( "delay",      "Delay",       "ms",     conv_num_positive, 10 ),
+    ( "jitter",     "Jitter",      "ms",     conv_num_positive, 10 ) ]
+link_param_loss = [
+    ( "loss",       "Packet Loss", "%",      conv_num_percent,  10 ),
+    ( "loss_burst", "Loss Burst",  "Pkts",   conv_num_ge_one,   10 ) ]
+link_param_all = link_param_bandwidth + link_param_delay + link_param_loss
+
+
+# get link configuration
+def get_link(link, link_params):
+    global config
+    title = link.replace('_to_', ' -> ')
+
+    # convert link parameter to strings
+    fields = []
+    for param in link_params:
+        val = config[link].get(param[0])
+        if val is None:
+            val = ""
+        else:
+            val = str(val)
+        fields.append(val)
+
+    # get parameter, until no errors left
+    ok = False
+    while not ok:
+        # create elements array for dialog.form
+        elements = []
+        i = 0
+        for param in link_params:
+            label = param[1]
+            if param[2] is not None:
+                label += " [" + param[2] + "]"
+            elements.append((label, i+1, 2, fields[i], i+1, 22, param[4], 0))
+            i += 1
+
+        # get parameter
+        code, fields = d.form("Link configuration " + title, elements,
+                              title=" "+title+" ")
+        if code != Dialog.OK:
+            break
+
+        # convert string fields to data
+        data = {}
+        ok = True
+        i = 0
+        for param in link_params:
+            try:
+                data[param[0]] = param[3](fields[i])
+            except ValueError as err:
+                ok = False
+                d.msgbox("Input error !!!\n\n" + param[1] + ":\n" + str(err))
+                break
+            i += 1
+        # additinal checks
+        if ok and data.get('delay') is not None and \
+           data.get('jitter') is not None and \
+           data['jitter'] > data['delay']:
+            ok = False
+            d.msgbox("Input error !!!\n\nJitter must be less than delay.")
+        # all fine, handle some special values and copy data to link config
+        if ok:
+            if data.get('delay') == 0:
+                data['delay'] = None
+            if data.get('delay') is None or data.get('jitter') == 0:
+                data['jitter'] = None
+            if data.get('loss') == 0:
+                data['loss'] = None
+            if data.get('loss') is None or data.get('loss_burst') == 1:
+                data['loss_burst'] = None
+            for param in data:
+                config[link][param] = data[param]
+    return
+
+
+# menu functions
+def menu_0to1():
+    get_link('eth0_to_eth1', link_param_all)
+
+
+def menu_0to1_bandwidth():
+    get_link('eth0_to_eth1', link_param_bandwidth)
+
+
+def menu_0to1_delay():
+    get_link('eth0_to_eth1', link_param_delay)
+
+
+def menu_0to1_loss():
+    get_link('eth0_to_eth1', link_param_loss)
+
+
+def menu_asymmetric():
+    global config
+    code = d.yesno("Do you want to change to symmetric mode?")
+    if code == Dialog.OK:
+        config['symmetric'] = True
+        del config['eth1_to_eth0']
+
+
+def menu_symmetric():
+    global config
+    code = d.yesno("Do you want to change to asymmetric mode?")
+    if code == Dialog.OK:
+        config['symmetric'] = False
+        config['eth1_to_eth0'] = copy.deepcopy(config['eth0_to_eth1'])
+
+
+def menu_1to0():
+    if config['symmetric']:
+        menu_symmetric()
+    else:
+        get_link('eth1_to_eth0', link_param_all)
+
+
+def menu_1to0_bandwidth():
+    get_link('eth1_to_eth0', link_param_bandwidth)
+
+
+def menu_1to0_delay():
+    get_link('eth1_to_eth0', link_param_delay)
+
+
+def menu_1to0_loss():
+    get_link('eth1_to_eth0', link_param_loss)
+
+
+def menu_load():
+    global config
+    title = " Load Configuration "
+    code, path = d.fselect("configs/", 10, 60, title=title)
+    if code == Dialog.OK:
+        try:
+            with open(path, "r") as f:
+                config = json.load(f)
+        except (ValueError, IOError, OSError) as err:
+            d.msgbox("Error !!!\n\n" + str(err), title=title)
+
+
+def menu_save():
+    title = " Save Configuration "
+    code, path = d.fselect("configs/", 10, 60, title=title)
+    if code == Dialog.OK:
+        try:
+            with open(path, "w") as f:
+                json.dump(config, f, sort_keys=True, indent=4,
+                          separators=(',', ': '))
+                f.write("\n")
+        except (ValueError, IOError, OSError) as err:
+            d.msgbox("Error !!!\n\n" + str(err), title=title)
+
+    # backup to persistent disk
+    subprocess.call(['filetool.sh', '-b'],
+                    stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL,
+                    stderr=subprocess.DEVNULL)
+
+
+def menu_shell():
+    d.clear()
+    print('Starting sub-shell, return with "exit"...')
+    subprocess.call('/bin/sh')
+
+
+def menu_shutdown():
+    d.clear()
+    subprocess.call(['sudo', 'poweroff'])
+
+
+menu_functions = {
+    'eth0->eth1':    menu_0to1,
+    '  Bandwidth':   menu_0to1_bandwidth,
+    '  Delay':       menu_0to1_delay,
+    '  Loss':        menu_0to1_loss,
+    'eth1->eth0':    menu_1to0,
+    '  Asymmetric':  menu_asymmetric,
+    '  Symmetric':   menu_symmetric,
+    '  Bandwidth ':  menu_1to0_bandwidth,
+    '  Delay ':      menu_1to0_delay,
+    '  Loss ':       menu_1to0_loss,
+    'Load':          menu_load,
+    'Save':          menu_save,
+    'Shell':         menu_shell,
+    'Shutdown':      menu_shutdown
+}
+
+
+# Main starts here
+try:
+    # create config subdirectory
+    os.makedirs("configs", exist_ok=True)
+    # try to load initial configuration
+    try:
+        with open("configs/init", "r") as f:
+            config = json.load(f)
+    except (ValueError, IOError, OSError):
+        pass
+
+    # input loop
+    while True:
+        # set parameter in linux
+        if conf_netem('eth0_to_eth1', 'eth1'):
+            if config['symmetric']:
+                conf_netem('eth0_to_eth1', 'eth0')
+            else:
+                conf_netem('eth1_to_eth0', 'eth0')
+
+        # main menue
+        choices = [ ('eth0->eth1',  "Configure link eth0 -> eth1"),
+                    ('  Bandwidth', string_bandwidth('eth0_to_eth1')),
+                    ('  Delay',     string_delay('eth0_to_eth1')),
+                    ('  Loss',      string_loss('eth0_to_eth1')),
+                    ('eth1->eth0',  "Configure link eth1 -> eth0") ]
+        if config['symmetric']:
+            choices += [ ('  Symmetric', "Same config as eth0 -> eth1") ]
+        else:
+            choices += [ ('  Asymmetric', "Use specific configuration"),
+                         ('  Bandwidth ', string_bandwidth('eth1_to_eth0')),
+                         ('  Delay ',     string_delay('eth1_to_eth0')),
+                         ('  Loss ',      string_loss('eth1_to_eth0')) ]
+        choices += [ ("Load",     "Load configuration from file"),
+                     ("Save",     "Save configuration to file"),
+                     ("Shell",    "Open a console"),
+                     ("Shutdown", "Shutdown the VM") ]
+        code, tag = d.menu("NETem Configuration", choices=choices,
+                           title=" NETem Configuration ", no_cancel=True)
+        if code == Dialog.OK and tag in menu_functions:
+            menu_functions[tag]()
+
+# intercept Ctrl-C
+except KeyboardInterrupt:
+    d.clear()
+    exit(0)