mac80211_hwsim: 802.11 radio simulator for mac80211

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.
Signed-off-by: Jouni Malinen <j@w1.fi>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Documentation/networking/mac80211_hwsim/README

+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

Documentation/networking/mac80211_hwsim/hostapd.conf

+interface=wlan0
+driver=nl80211
+
+hw_mode=g
+channel=1
+ssid=mac80211 test
+
+wpa=2
+wpa_key_mgmt=WPA-PSK
+wpa_pairwise=CCMP
+wpa_passphrase=12345678

Documentation/networking/mac80211_hwsim/wpa_supplicant.conf

+ctrl_interface=/var/run/wpa_supplicant
+
+network={
+	ssid="mac80211 test"
+	psk="12345678"
+	key_mgmt=WPA-PSK
+	proto=WPA2
+	pairwise=CCMP
+	group=CCMP
+}

drivers/net/wireless/Kconfig

@@ -673,6 +673,19 @@ config ADM8211
 
 	  Thanks to Infineon-ADMtek for their support of this driver.
 
+config MAC80211_HWSIM
+	tristate "Simulated radio testing tool for mac80211"
+	depends on MAC80211 && WLAN_80211
+	---help---
+	  This driver is a developer testing tool that can be used to test
+	  IEEE 802.11 networking stack (mac80211) functionality. This is not
+	  needed for normal wireless LAN usage and is only for testing. See
+	  Documentation/networking/mac80211_hwsim for more information on how
+	  to use this tool.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called mac80211_hwsim.  If unsure, say N.
+
 source "drivers/net/wireless/p54/Kconfig"
 source "drivers/net/wireless/ath5k/Kconfig"
 source "drivers/net/wireless/iwlwifi/Kconfig"

drivers/net/wireless/Makefile

@@ -62,3 +62,5 @@ obj-$(CONFIG_RT2X00)	+= rt2x00/
 obj-$(CONFIG_P54_COMMON)	+= p54/
 
 obj-$(CONFIG_ATH5K)	+= ath5k/
+
+obj-$(CONFIG_MAC80211_HWSIM)	+= mac80211_hwsim.o