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. 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 simulated (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.

  
  # 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

  
  
  More test cases are available in hostap.git:
  git://w1.fi/srv/git/hostap.git and mac80211_hwsim/tests subdirectory
  (http://w1.fi/gitweb/gitweb.cgi?p=hostap.git;a=tree;f=mac80211_hwsim/tests)