Wireless daemon for Linux
*************************
Copyright (C) 2013-2019 Intel Corporation. All rights reserved.
Compilation and installation
============================
In order to compile the source code you need following software packages:
- GCC compiler
- GNU C library
- Embedded Linux library
- readline (command line client)
To configure run:
./configure --prefix=/usr
Configure automatically searches for all required components and packages.
To compile and install run:
make && make install
Embedded Linux library
======================
In order to compile the daemon and control utility the development version
of Embedded Linux library is required to be present. The development
repositories can be found here:
git://git.kernel.org/pub/scm/libs/ell/ell.git
https://kernel.googlesource.com/pub/scm/libs/ell/ell.git
The build systems requires that the Embedded Linux library source code
is available on the same top level directory as the Wireless daemon
source code:
.
|--- ell
| |--- ell
| `--- unit
`--- iwd
|--- src
`--- client
It is not required to build or install Embedded Linux library. The build
will happen when building the Wireless daemon and it will then be linked
internally.
When using --enable-external-ell build option, it is not required that the
Embedded Linux library source code is available in the top level directory.
The tarballs include a copy of the Embedded Linux library source files. When
building from the tarballs, then it is not required to have the library
sources available in the top level directory.
Manual pages
============
The manual pages are generated from reStructuredText markup source files
during the normal build process. The generation requires the rst2man utility
from Python Docutils project. If rst2man is for some reason not available,
using --disable-manual-pages will skip the manual pages generation and
installation.
When building from the tarballs, a copy of the generated manual pages is
included and the rst2man utility is actually not needed.
Configuration and options
=========================
The configuration system provides switches to disable certain build time
configuration options which are generally useful and enabled by default:
--disable-daemon
Disable installation of Wireless daemon
By default the Wireless daemon binary iwd is enabled and
placed into --libexecdir directory.
--disable-client
Disable installation of Wireless client utility
By default the Wireless client binary iwctl is enabled
and place into --bindir directory.
--disable-monitor
Disable installation of Wireless monitor utility
By default the Wireless monitor binary iwmon is enabled
and place into --bindir directory.
--disable-dbus-policy
Disable installation of D-Bus system policy configuration
By default the accompanying D-Bus policy file will be
installed in the D-Bus data directory. The location of
that directory will be automatically detected or can be
manually configured via the --with-dbus-datadir option.
The D-Bus policy is required for daemons to gain service
name ownership and clients to access them. When disabling
this option, manual installation of D-Bus polices is
required.
Note: This option affects all D-Bus policy configurations.
--disable-systemd-service
Disable installation of systemd service configuration
By default the accompanying systemd service unit with
D-Bus autostart configuration will be installed. The
locations will be automatically detected or can be
manually configured via --with-dbus-busdir option
and --with-systemd-unitdir option.
Using systemd is optional, but highly recommended. When
disabling this option, manual installation is required.
Note: This option affects all systemd unit setups.
--disable-manual-pages
Disable generation and installation of manual pages
By default all available manual pages will be generated
and installed. When disabling this options, no manual
pages are installed.
Note: This options affects all manual pages.
When building for a system that wants to use wireless technology, disabling
any of the above options makes only limited sense. It may break the general
setup and usability for wireless connections.
The configuration system provides switches for optional build time features
that can be enabled if the functionality is required:
--enable-external-ell
Enable usage of external Embedded Linux library
This allows using an externally installed Embedded Linux
library instead of using the internal copy of ELL.
Since the public API of Embedded Linux library is not yet
stable, the usage of the internal ELL copy is preferred.
--enable-wired
Enable installation of Ethernet authentication daemon
This allows enabling the Ethernet daemon binary ead which
is then placed into --libexecdir directory.
With this option the support for 802.1x for wired Ethernet
connections can be enabled. It provides its own D-Bus
policy and systemd configuration.
--enable-hwsim
Enable installation of Wireless simulation utility
This allows enabling the Simulation daemon binary hwsim
which is then placed into --bindir directory.
With this utility and mac80211_hwim kernel module the
simulation of 802.11 networks can be tested. It provides
its own D-Bus policy configuration.
This utility is only useful for developers and should not
be considered for general installation. For this reason
no systemd configuration is provided.
--enable-tools
Enable compilation of various testing utilities
This enables building of all utilities that are however
not installed and only useful during development.
--enable-ofono
Enable support for oFono SIM authentication
Note: With --disable-daemon this option is ignored
Netlink monitoring
==================
The included iwmon utility can be used to monitor the 802.11 subsystem
generic netlink commands and events. It uses the nlmon kernel driver
from Linux 3.10 and later. On startup network monitor interface named
named 'nlmon' is created unless another interface name is given on the
command line. If the monitor interface was created by the iwmon utility,
it will be removed on program exit.
Manually the monitor interface can be created using the following
commands:
ip link add name nlmon type nlmon
ip link set dev nlmon allmulticast on
ip link set dev nlmon up
It is possible to create netlink traces in PCAP format using tcpdump
and then read them via iwmon utility:
tcpdump -i nlmon -w trace-file.pcap
The resulting PCAP files will use Linux cooked packet format containing
packets with ARPHRD_NETLINK type. They can be read using iwmon:
iwmon -r trace-file.pcap
At this time iwmon is not able to write PCAP files by itself. This might
change in future versions.
When also the authentication protocol traffic on port 0x888e (ETH_P_PAE)
is needed, then a second capture is required:
tcpdump -i any 'ether proto 0x888e' -w trace-pae.pcap
It is possible to combine these two PCAP files using the mergecap utility
and create a combined trace file:
mergecap -F pcap -w trace.pcap trace-file.pcap trace-pae.pcap
This will create a trace.pcap file that includes the complete picture
of nl80211 netlink traffic and authentication messages. All packets are
merged in chronological order based on timestamps.
Unfortunately it is not possible to instruct tcpdump filtering to do
this in a single capture. Post-processing of the PCAP files is required
at the moment.
Simulating devices
==================
The Linux driver mac80211_hwsim provides the functionality to simulate
Wireless devices using fake virtual air. Just load the module.
modprobe mac80211_hwsim radios=0
Providing the radios=0 is important since otherwise it starts out with
two new Wireless radios by default.
With the provided hwsim utility it is now possible to add and remove
virtual radio devices.
hwsim --create --keep
hwsim --destroy=<radio-id>
The radio id assigned to each virtual device is its internal id used
by the Wireless device.
Information
===========
Mailing list:
https://lists.01.org/postorius/lists/iwd.lists.01.org/
IRC:
irc://irc.oftc.net/#iwd
Wiki:
https://iwd.wiki.kernel.org/