Documentation/networking/mac80211_hwsim/README - maze/linux - Git at Google

 mac80211_hwsim - software simulator of 802.11 radio(s) for mac80211
 Copyright (c) 2008, Jouni Malinen <j@w1.fi>

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License version 2 as
 published by the Free Software Foundation.


 Introduction

 mac80211_hwsim is a Linux kernel module that can be used to simulate
 arbitrary number of IEEE 802.11 radios for mac80211 on a single
 device. It can be used to test most of the mac80211 functionality and
 user space tools (e.g., hostapd and wpa_supplicant) in a way that
 matches very closely with the normal case of using real WLAN
 hardware. From the mac80211 view point, mac80211_hwsim is yet another
 hardware driver, i.e., no changes to mac80211 are needed to use this
 testing tool.

 The main goal for mac80211_hwsim is to make it easier for developers
 to test their code and work with new features to mac80211, hostapd,
 and wpa_supplicant. The simulated radios do not have the limitations
 of real hardware, so it is easy to generate an arbitrary test setup
 and always reproduce the same setup for future tests. In addition,
 since all radio operation is simulated, any channel can be used in
 tests regardless of regulatory rules.

 mac80211_hwsim kernel module has a parameter 'radios' that can be used
 to select how many radios are simulates (default 2). This allows
 configuration of both very simply setups (e.g., just a single access
 point and a station) or large scale tests (multiple access points with
 hundreds of stations).

 mac80211_hwsim works by tracking the current channel of each virtual
 radio and copying all transmitted frames to all other radios that are
 currently enabled and on the same channel as the transmitting
 radio. Software encryption in mac80211 is used so that the frames are
 actually encrypted over the virtual air interface to allow more
 complete testing of encryption.

 A global monitoring netdev, hwsim#, is created independent of
 mac80211. This interface can be used to monitor all transmitted frames
 regardless of channel.


 Simple example

 This example shows how to use mac80211_hwsim to simulate two radios:
 one to act as an access point and the other as a station that
 associates with the AP. hostapd and wpa_supplicant are used to take
 care of WPA2-PSK authentication. In addition, hostapd is also
 processing access point side of association.

 Please note that the current Linux kernel does not enable AP mode, so a
 simple patch is needed to enable AP mode selection:
 http://johannes.sipsolutions.net/patches/kernel/all/LATEST/006-allow-ap-vlan-modes.patch


 # Build mac80211_hwsim as part of kernel configuration

 # Load the module
 modprobe mac80211_hwsim

 # Run hostapd (AP) for wlan0
 hostapd hostapd.conf

 # Run wpa_supplicant (station) for wlan1
 wpa_supplicant -Dwext -iwlan1 -c wpa_supplicant.conf
	mac80211_hwsim - software simulator of 802.11 radio(s) for mac80211
	Copyright (c) 2008, Jouni Malinen <j@w1.fi>

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License version 2 as
	published by the Free Software Foundation.


	Introduction

	mac80211_hwsim is a Linux kernel module that can be used to simulate
	arbitrary number of IEEE 802.11 radios for mac80211 on a single
	device. It can be used to test most of the mac80211 functionality and
	user space tools (e.g., hostapd and wpa_supplicant) in a way that
	matches very closely with the normal case of using real WLAN
	hardware. From the mac80211 view point, mac80211_hwsim is yet another
	hardware driver, i.e., no changes to mac80211 are needed to use this
	testing tool.

	The main goal for mac80211_hwsim is to make it easier for developers
	to test their code and work with new features to mac80211, hostapd,
	and wpa_supplicant. The simulated radios do not have the limitations
	of real hardware, so it is easy to generate an arbitrary test setup
	and always reproduce the same setup for future tests. In addition,
	since all radio operation is simulated, any channel can be used in
	tests regardless of regulatory rules.

	mac80211_hwsim kernel module has a parameter 'radios' that can be used
	to select how many radios are simulates (default 2). This allows
	configuration of both very simply setups (e.g., just a single access
	point and a station) or large scale tests (multiple access points with
	hundreds of stations).

	mac80211_hwsim works by tracking the current channel of each virtual
	radio and copying all transmitted frames to all other radios that are
	currently enabled and on the same channel as the transmitting
	radio. Software encryption in mac80211 is used so that the frames are
	actually encrypted over the virtual air interface to allow more
	complete testing of encryption.

	A global monitoring netdev, hwsim#, is created independent of
	mac80211. This interface can be used to monitor all transmitted frames
	regardless of channel.


	Simple example

	This example shows how to use mac80211_hwsim to simulate two radios:
	one to act as an access point and the other as a station that
	associates with the AP. hostapd and wpa_supplicant are used to take
	care of WPA2-PSK authentication. In addition, hostapd is also
	processing access point side of association.

	Please note that the current Linux kernel does not enable AP mode, so a
	simple patch is needed to enable AP mode selection:
	http://johannes.sipsolutions.net/patches/kernel/all/LATEST/006-allow-ap-vlan-modes.patch


	# Build mac80211_hwsim as part of kernel configuration

	# Load the module
	modprobe mac80211_hwsim

	# Run hostapd (AP) for wlan0
	hostapd hostapd.conf

	# Run wpa_supplicant (station) for wlan1
	wpa_supplicant -Dwext -iwlan1 -c wpa_supplicant.conf