Beyond Linux® From Scratch (systemd Edition) - Version 11.2

Chapter 16. Networking Utilities

NetworkManager-1.38.4

Introduction to NetworkManager

NetworkManager is a set of co-operative tools that make networking simple and straightforward. Whether you use WiFi, wired, 3G, or Bluetooth, NetworkManager allows you to quickly move from one network to another: Once a network has been configured and joined once, it can be detected and re-joined automatically the next time it's available.

This package is known to build and work properly using an LFS-11.2 platform.

[Note]

Note

Make sure that you disable the systemd-networkd service or configure it not to manage the interfaces you want to manage with NetworkManager.

Package Information

NetworkManager Dependencies

Required

jansson-2.14 and libndp-1.8

Recommended

cURL-7.84.0, DHCP-4.4.3 (client only), gobject-introspection-1.72.0, iptables-1.8.8, newt-0.52.21 (for nmtui), nss-3.82, Polkit-121, PyGObject-3.42.2, Systemd-251, UPower-1.90.0, Vala-0.56.2, and wpa_supplicant-2.10 (built with D-Bus support)

Optional

BlueZ-5.65, D-Bus Python-1.2.18 (for the test suite), GnuTLS-3.7.7 (used if nss-3.82 is not found), GTK-Doc-1.33.2, libpsl-0.21.1, Qt-5.15.5 (for examples), ModemManager-1.18.10, Valgrind-3.19.0, dnsmasq, firewalld, libaudit, libteam, mobile-broadband-provider-info, PPP, and RP-PPPoE

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/NetworkManager

Kernel Configuration

If you wish to run the tests, enable the following options in the kernel configuration and recompile the kernel if necessary: 

Device Drivers --->
  [*] Network device support         [CONFIG_NETDEVICES] --->
    [*] Bonding driver support       [CONFIG_BONDING]
    [*] Dummy net driver support     [CONFIG_DUMMY]
    [*] Ethernet team driver support [CONFIG_NET_TEAM]

Installation of NetworkManager

If Qt-5.15.5 is installed and the Qt based examples are desired, fix two meson.build files: 

sed -e 's/-qt4/-qt5/'              \
    -e 's/moc_location/host_bins/' \
    -i examples/C/qt/meson.build   &&

sed -e 's/Qt/&5/'                  \
    -i meson.build

Fix the python scripts so that they use Python 3: 

grep -rl '^#!.*python$' | xargs sed -i '1s/python/&3/'

Install NetworkManager by running the following commands: 

mkdir build &&
cd    build    &&

CXXFLAGS+="-O2 -fPIC"            \
meson --prefix=/usr              \
      --buildtype=release        \
      -Dlibaudit=no              \
      -Dlibpsl=false             \
      -Dnmtui=true               \
      -Dovs=false                \
      -Dppp=false                \
      -Dselinux=false            \
      -Dqt=false                 \
      -Dsession_tracking=systemd \
      -Dmodem_manager=false      \
      .. &&
ninja

An already active graphical session with a bus address is necessary to run the tests. To test the results, as the root user, issue: ninja test. One test, test-core, is known to fail.

Now, as the root user: 

ninja install &&
mv -v /usr/share/doc/NetworkManager{,-1.38.4}

Command Explanations

CXXFLAGS="-O2 -fPIC": These compiler options are necessary to build the Qt5 based examples.

--buildtype=release: Specify a buildtype suitable for stable releases of the package, as the default may produce unoptimized binaries.

-Ddocs=true: Use this switch to enable building man pages and documentation if GTK-Doc-1.33.2 is installed.

-Dnmtui=true: This parameter enables building nmtui.

-Dlibpsl=false and -Dovs=false: These switches disable building with the respective libraries. Remove if you have the needed libraries installed.

-Dmodem_manager=false: This switch is required if ModemManager is not installed. Omit if you have built ModemManager and mobile-broadband-provider-info.

-Dsession_tracking=systemd: This switch is used to set systemd-logind as the default program for session tracking.

-Dsystemdsystemunitdir=/lib/systemd/system: This switch is used to set the correct installation directory for systemd units.

-Dppp=false: This parameter disables PPP support in NetworkManager.

-Dlibaudit=no and -Dselinux=false: libaudit and SELinux are not used in BLFS.

-Dqt=false: disables the QT examples. Omit if you have QT available and wish to install the examples.

Configuring NetworkManager

Config Files

/etc/NetworkManager/NetworkManager.conf

Configuration Information

For NetworkManager to work, at least a minimal configuration file must be present. Such a file is not installed with make install. Issue the following command as the root user to create a minimal NetworkManager.conf file: 

cat >> /etc/NetworkManager/NetworkManager.conf << "EOF"
[main]
plugins=keyfile
EOF

This file should not be modified directly by users of the system. Instead, system specific changes should be made using configuration files in the /etc/NetworkManager/conf.d directory.

To allow polkit to manage authorizations, add the following configuration file: 

cat > /etc/NetworkManager/conf.d/polkit.conf << "EOF"
[main]
auth-polkit=true
EOF

To use something other than the built-in dhcp client (recommended if using only nmcli), use the following configuration (valid values include either dhclient or internal): 

cat > /etc/NetworkManager/conf.d/dhcp.conf << "EOF"
[main]
dhcp=dhclient
EOF

To prevent NetworkManager from updating the /etc/resolv.conf file, add the following configuration file: 

cat > /etc/NetworkManager/conf.d/no-dns-update.conf << "EOF"
[main]
dns=none
EOF

For additional configuration options, see man 5 NetworkManager.conf.

To allow regular users to configure network connections, you should add them to the netdev group, and create a polkit rule that grants access. Run the following commands as the root user: 

groupadd -fg 86 netdev &&
/usr/sbin/usermod -a -G netdev <username>

cat > /usr/share/polkit-1/rules.d/org.freedesktop.NetworkManager.rules << "EOF"
polkit.addRule(function(action, subject) {
    if (action.id.indexOf("org.freedesktop.NetworkManager.") == 0 && subject.isInGroup("netdev")) {
        return polkit.Result.YES;
    }
});
EOF

Systemd Unit

To start the NetworkManager daemon at boot, enable the previously installed systemd unit by running the following command as the root user:

[Note]

Note

If using Network Manager to manage an interface, any previous configuration for that interface should be removed, and the interface brought down prior to starting Network Manager. 

systemctl enable NetworkManager

Starting in version 1.11.2 of NetworkManager, a systemd unit named NetworkManager-wait-online.service is enabled, which is used to prevent services that require network connectivity from starting until NetworkManager establishes a connection. To disable this behavior, run the following command as the root user: 

systemctl disable NetworkManager-wait-online

Contents

Installed Programs: NetworkManager, nmcli, nm-online, nmtui, and, symlinked to nmtui: nmtui-connect, nmtui-edit, and nmtui-hostname
Installed Libraries: libnm.so and several modules under /usr/lib/NetworkManager
Installed Directories: /etc/NetworkManager, /usr/include/libnm, /usr/lib/NetworkManager, /usr/share/doc/NetworkManager-1.38.4, /usr/share/gtk-doc/html/{libnm,NetworkManager} (if the documentation is built), and /var/lib/NetworkManager

Short Descriptions

nmcli

is a command-line tool for controlling NetworkManager and getting its status

nm-online

is an utility to determine whether you are online

nmtui

is an interactive ncurses-based user interface for nmcli

nmtui-connect

is an interactive ncurses-based user interface to activate/deactivate connections

nmtui-edit

is an interactive ncurses-based user interface to edit connections

nmtui-hostname

is an interactive ncurses-based user interface to edit the hostname

NetworkManager

is the network management daemon

libnm.so

contains functions used by NetworkManager