iwd

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iwd (iNet Wireless Daemon) is a wireless daemon intended to replace wpa_supplicant, written by Intel.

Potential benefits of iwd over wpa_supplicant include:

  • simplification of network management
  • faster network discovery
  • fast and reliable roaming
  • using less system resources
  • using features offered by the Linux kernel
  • support for enterprise security methods like EAP
  • support for kernel asymmetric key rings and Trusted Platform Modules (TPM)
  • support for multiple clients

Background

For details readers are referred to the LWN article "iwd: simplifying WiFi management" in 2018 by Jonathan Corbet.

Why does iwd have to replace wpa_supplicant? In fact users can continue to use wpa_supplicant if they are satisfied.

For developers however wpa_supplicant is bad. It was the first software for Wifi authentication, and in the end it became too big and too complicated. Although it came to have many problems, it became difficult to fix them. Very few releases have been made since the version 2.0 in 2013.

Then the community decided to write a new software from scratch, and it is iwd.

Installation

Kernel

General instructions for WiFi apply, including the required device drivers and IEEE 802.11 support.

In addition iwd requires the Linux kernel to have quite some options to be enabled. For systems running on a AMD64 architecture, or CPUs that support SSSE3 or X86_AES instructions some hardware acceleration can be achieved. The cpuid2cpuflags utility can be used to check for support.

KERNEL 
Security options  --->
    [*] Enable access key retention support
    [*] Diffie-Hellman operations on retained keys
Networking support  --->
    [*] Wireless  --->
        <M> cfg80211 - wireless configuration API
Cryptographic API  --->
    Public-key cryptography  --->
        [*] RSA (Rivest-Shamir-Adleman)
        [*] DH (Diffie-Hellman)
    Block ciphers  --->
        [*] AES (Advanced Encryption Standard)
        [*] AES (Advanced Encryption Standard) (fixed time)
        [*] DES and Triple DES EDE
    Length-preserving ciphers and modes  --->
        [*] ARC4 (Alleged Rivest Cipher 4)
        [*] ECB (Electronic Codebook)
    Hashes, digests and MACs  --->
        [*] HMAC (Keyed-Hash MAC)
        [*] MD4
        [*] MD5
        [*] SHA-1
        [*] SHA-224 and SHA-256
        [*] SHA-384 and SHA-512
     Accelerated Cryptographic Algorithms for CPU (x86)  --->
        [*] Ciphers: AES, modes: ECB, CBC, CTS, CTR, XTR, XTS, GCM (AES-NI)               // X86_AES
        [*] Ciphers: Triple DES EDE with modes: ECB, CBC                                  // AMD64
        [*] Hash functions: SHA-1 (SSSE3/AVX/AVX2/SHA-NI)                                 // AMD64 and SSSE3
        [*] Hash functions: SHA-224 and SHA-256 (SSSE3/AVX/AVX2/SHA-NI)                   // AMD64 and SSSE3
        [*] Hash functions: SHA-384 and SHA-512 (SSSE3/AVX/AVX2/SHA-NI)                   // AMD64 and SSSE3
     Userspace interface  --->
        [*] Hash algorithms
        [*] Symmetric key cipher algorithms
     [*] Asymmetric (public-key cryptographic) key type  --->
        [*] Asymmetric public-key crypto algorithm subtype
        [*] X.509 certificate parser
        [*] PKCS#8 private key parser                                                     // Linux kernel 4.20 or higher
        [*] PKCS#7 message parser

USE flags

Some packages are aware of the iwd USE flag.

USE flags for net-wireless/iwd Wireless daemon for linux

+client Enable iwctl client tool
+monitor Enable iwmon monitor tool
ofono Enable support for oFono SIM authentication
selinux !!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur
standalone Enable standalone mode with built-in DHCP client and DNS handling"
systemd Use systemd-resolve rather than resolvconf for DNS handling in standalone mode
wired Enable ethernet authentication daemon
Data provided by the Gentoo Package Database · Last update: 2024-11-26 16:29 More information about USE flags

Emerge

Install the net-wireless/iwd package:

root #emerge --ask net-wireless/iwd

Interface management

On iwd startup it may destroy an existing network interface and create a new one. For example iwd might rename the interface wlp2s0 to wlan0. (The former is typically created by udev.) When iwd terminates, it destroys the wireless interface it created. (It does not necessarily mean the original name is restored.) The newly created interface will be configured optimally for iwd's use.

It is possible to suppress this behavior by:

  • passing commandline options -p (+the the name of the phy) and -i (+ the name of the interface) to the iwd daemon, or
  • configuring setting [DriverQuirks].DefaultInterface to a comma-seperated list of drivers or glob matches in /etc/iwd/main.conf

It may also be necessary to prevent udev from renaming the interface.

In the remainder of this article, it is assumed that the wireless interface is named wlan0.

Iwd daemon configuration

Iwd keeps its main configuration file in /etc/iwd/main.conf. It is documented in the official manual page.

Note
iwd has updated its configuration file syntax. Previous settings like enable_network_configuration are now obsolete and replaced by EnableNetworkConfiguration.

Starting and stopping the iwd service

OpenRC

Note
NetworkManager takes care of starting the process for iwd. If the iwd service is started, it will gracefully crash.

Please make sure that wpa_supplicant is stopped prior to starting iwd:

root #rc-update delete wpa_supplicant
root #rc-service wpa_supplicant stop

Then start iwd, and add it to the default runlevel:

root #rc-update add iwd default
root #rc-service iwd start

Systemd

Note
NetworkManager is able to use D-Bus to start the iwd service when needed. Therefore the service doesn't need to be enabled explicitly.

Any active wpa_supplicant services should be stopped prior to starting the iwd service:

root #systemctl disable --now wpa_supplicant

The iwd service can be started as per:

root #systemctl enable --now iwd

Network management

Important
Gentoo is all about choice, so there are various methods available for network management. Readers should notice: iwd is new, and not all the methods below may fully support iwd.

Be sure to heed the warning in the network management article about mixing and matching the different methods for network management.

Netifrc

netifrc is Gentoo's default method of managing networks. It doesn't officially support iwd as a backend yet, but it works, barring minor issues, see bug #690808.

Enable iwd by editing /etc/conf.d/net file:

FILE /etc/conf.d/net
modules_phy0="iwd debug"
modules_wlan0="iwd debug"
iwd_wlan0="phy0 debug"
config_wlan0="dhcp"

The debug parameters help to resolve the minor issues. When strange behavior is observed then please comment on bug #690808 and upload the syslog.

Netifrc will start iwd as needed, so no need for the iwd deamon to be started by OpenRC, instead create a symlink from /etc/init.d/net.wlan0 to /etc/init.d/net.lo, and start the net.wlan0 service:

root #rc-service iwd stop
root #rc-update delete iwd
root #cd /etc/init.d
root #ln -s net.lo net.wlan0
root #rc-service net.wlan0 start

iwd native

iwd contains a DHCP client and can manage routes and DNS resolving. If the standalone USE flag is not set, the following manual configuration is necessary; edit /etc/iwd/main.conf as follows:

FILE /etc/iwd/main.conf
[General]
EnableNetworkConfiguration=true
[Network]
RoutePriorityOffset=200
NameResolvingService=resolvconf

Where:

  • EnableNetworkConfiguration is required to activate the native network management
  • RoutePriorityOffset is optional and sets the route metric
  • NameResolvingService is optional and can be used to configure a DNS manager like 'resolvconf' from net-dns/openresolv or 'systemd'.

dhcpcd

Add dhcpcd to the default runlevel and start it up, next to the iwd service:

root #rc-update add dhcpcd default
root #rc-service dhcpcd start

NetworkManager

NetworkManager has been supporting iwd backend since version 1.12. Verify the iwd USE flag is set:

root #echo "net-misc/networkmanager iwd" >> /etc/portage/package.use/networkmanager
root #emerge --ask --newuse net-misc/networkmanager

Enable the iwd backend for WiFi devices as per upstream's instructions[1]:

FILE /etc/NetworkManager/conf.d/iwd.conf
[device]
wifi.backend=iwd

Starting with NetworkManager 1.30 it is possible to enable iwd-driven autoconnect logic instead of NetworkManager's.

FILE /etc/NetworkManager/conf.d/iwd.conf
[device]
wifi.backend=iwd
wifi.iwd.autoconnect=yes

Restart the NetworkManager service:

For OpenRC:

root #rc-service NetworkManager restart

For systemd:

root #systemctl restart NetworkManager

ConnMan

ConnMan supports iwd somewhat. Make sure to set the iwd USE flag and (re-)emerge:

root #echo "net-misc/connman iwd" >> /etc/portage/package.use/zz-autounmask
root #emerge --ask --newuse net-misc/connman

ConnMan still relies on wpa_supplicant for scanning, but connecting via iwd is possible.

systemd-networkd

systemd-networkd will handle iwd-managed interfaces just like any other network interface. Add a .network file and start or restart the service:

FILE /etc/systemd/network/wlan0.network
[Match]
Name=wlan0

[Network]
DHCP=yes
IgnoreCarrierLoss=3s
root #systemctl enable --now systemd-networkd
root #systemctl enable --now systemd-resolved

Client software

Iwd comes with a commandline interface called iwctl when client USE flag enabled.

There are also a few graphical user interface based applications. These frontends communicate with iwd over D-Bus, and will not work with iwd versions without D-Bus.

Iwctl

iwctl is iwd's tool to control iwd. It supports both a command line interface and an interactive mode. A complete command line would be iwctl station list to see what adapters you might be able to use:

user $iwctl station list
                            Devices in Station Mode
--------------------------------------------------------------------------------
  Name                State          Scanning
--------------------------------------------------------------------------------
  wlan0               disconnected

An interactive session of iwctl commands can be used to connect to a WiFi network access point. First check the status of the WiFi network interface, set it in scanning mode if needed, and then obtain the list of WiFi access points. Finally connect to the access point.

user $iwctl
# station wlan0 show
                                 Station: wlan0
--------------------------------------------------------------------------------
  Settable  Property            Value
--------------------------------------------------------------------------------
            Scanning            no
            State               disconnected

# station wlan0 scan
# station wlan0 get-networks
                               Available networks
--------------------------------------------------------------------------------
    Network name                    Security  Signal
--------------------------------------------------------------------------------
    FRITZ!Box 7362 SL               psk       ***
    WLAN-105127                     psk       *

# station wlan0 connect "FRITZ!Box 7362 SL"
Type the network passphrase for FRITZ!Box 7362 SL psk.
Passphrase:

That last step would auto-generate the /var/lib/iwd/station.psk file.

Note that it is not possible to assign a priority to a network, instead iwd will prioritize networks based on:

  • signal strength level
  • security features
  • maximum rate
  • channel utilization
  • time since the last connect.

NetworkManager frontends

When using NetworkManager then gnome-extra/nm-applet or other NetworkManager frontends can be used as per normal to make connections.

Dedicated iwd clients

Configuration per connection

Connection settings can be edited manually if required. Iwd keeps its configuration file per connection in /var/lib/iwd/.

This directory contains files named like <station>.<networktype>, where:

  • station is the name (SSID) of the network
  • networktype can be:
    • psk for pre-shared key, like WPA-PSK or WPA2-PSK
    • 8021x for WPA-Enterprise, like EAP-PWD or EAP-PEAP.

The configuration settings are described in iwd.network. A few examples are given below.

Security

For WPA authentication the contents of the file looks like this:

FILE /var/lib/iwd/station.psk
[Security]
PreSharedKey=924179acd138039828674bb2339a4a2c95cce4a41deb934d99c00380d0be8490
Passphrase=<human readable password>

Passphrase in case of WPA2-PSK needs to be the same as is set in the router and is known from wpa_supplicant's psk= entries. There is no need to set PreSharedKey manually; it will be calculated and added to the configuration file automatically by iwd. (iwd does not have passhrase calculator, but it does not matter with this reason.)

Static network configuration

Iwd defaults to DHCP, either natively or using an external DHCP-client. For static IPv4 configuration add something like this to /var/lib/iwd/station.pwk:

FILE /var/lib/iwd/station.psk
[IPv4]
Address=192.168.1.100
Netmask=255.255.255.0
Gateway=192.168.1.1
Broadcast=192.168.1.255
DNS=192.168.1.1

See also

External resources

Man pages

General

  • Getting Started with iwd - Official upstream introduction
  • Iwd - Archlinux wiki article
  • eiwd - Unofficial iwd without D-Bus; fork of dylanaraps/eiwd, which was abandoned in 2020

References

  1. ↑ IWD Wiki, Using IWD with Network Manager
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