hostapd and wpa_supplicant include a test driver interface that allows them to be tested on a single host without any wireless hardware for development purposes. I have found this very valuable both for developing new functionality and for testing existing code. In order to provide similar mechanism for mac80211 developers and to extend the scope of suitable test cases for hostapd/wpa_supplicant, I've written a Linux kernel module that provides a similar test interface at a lower layer. mac80211_hwsim simulates WLAN hardware and the air interface between the radios by acting as a low-level radio driver for mac80211. Neither mac80211 nor user space programs need any changes to work with the simulated radios. The initial version of mac80211_hwsim is available from the mac80211_hwsim subdirectory of my hostap Git tree: git://w1.fi/srv/git/hostap.git http://w1.fi/gitweb/gitweb.cgi?p=hostap.git;a=tree;f=mac80211_hwsim If there is interest in moving mac80211_hwsim module into the Linux kernel tree, I'm open to doing that, too. I've included some more information about the code in the README file (see below) and there are also example configuration files for hostapd and wpa_supplicant to show how a WPA2-Personal connection can be opened with mac80211_hwsim. mac80211_hwsim is still very minimal, but I have added couple of TODO comments to the source code to indicate areas that I'm hoping to add for more complete support of mac80211 features. I would also be interested in feedback from other mac80211 developers on what kind of functionality would be useful to have in this kind of simulated test setup. I'm first looking into using this to develop IEEE 802.11w (management frame protection) support into mac80211 and I would expect that the current minimal design is enough for that, but there is certainly room for much more, e.g., in the area of simulating signal strength and packet loss for testing TX rate control, retransmission, and power save functionality. README: 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. 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 currently released Linux kernel (2.6.25) 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: make # Load the module insmod ./mac80211_hwsim.ko # Run hostapd (AP) for wlan0 hostapd hostapd.conf # Run wpa_supplicant (station) for wlan1 wpa_supplicant -Dwext -iwlan1 -c wpa_supplicant.conf -- Jouni Malinen PGP id EFC895FA -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
