mac80211_hwsim: 802.11 radio simulator for mac80211

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

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

ctrl_interface=/var/run/wpa_supplicant

network={

	ssid="mac80211 test"

	psk="12345678"

	key_mgmt=WPA-PSK

	proto=WPA2

	pairwise=CCMP

	group=CCMP

}

	  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"

obj-$(CONFIG_P54_COMMON)	+= p54/

obj-$(CONFIG_ATH5K)	+= ath5k/

obj-$(CONFIG_MAC80211_HWSIM)	+= mac80211_hwsim.o