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mac80211_hwsim: 802.11 radio simulator for mac80211

Browse Source 
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>
This commit is contained in:
Jouni Malinen 2008-06-11 10:42:31 +03:00 committed by John W. Linville
parent 14a08a7fcf
commit acc1e7a300
6 changed files with 637 additions and 0 deletions
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68
Documentation/networking/mac80211_hwsim/README Normal file
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@ -0,0 +1,68 @@
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

11
Documentation/networking/mac80211_hwsim/hostapd.conf Normal file
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@ -0,0 +1,11 @@
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

10
Documentation/networking/mac80211_hwsim/wpa_supplicant.conf Normal file
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@ -0,0 +1,10 @@
ctrl_interface=/var/run/wpa_supplicant
network={
ssid="mac80211 test"
psk="12345678"
key_mgmt=WPA-PSK
proto=WPA2
pairwise=CCMP
group=CCMP
}

13
drivers/net/wireless/Kconfig
View File

@ -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"

2
drivers/net/wireless/Makefile
View File

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

533
drivers/net/wireless/mac80211_hwsim.c Normal file
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@ -0,0 +1,533 @@
/*
* 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.
*/
/*
* TODO:
* - IBSS mode simulation (Beacon transmission with competition for "air time")
* - IEEE 802.11a and 802.11n modes
* - RX filtering based on filter configuration (data->rx_filter)
*/
#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>
#include <linux/if_arp.h>
#include <linux/rtnetlink.h>
#include <linux/etherdevice.h>
MODULE_AUTHOR("Jouni Malinen");
MODULE_DESCRIPTION("Software simulator of 802.11 radio(s) for mac80211");
MODULE_LICENSE("GPL");
static int radios = 2;
module_param(radios, int, 0444);
MODULE_PARM_DESC(radios, "Number of simulated radios");
static struct class *hwsim_class;
static struct ieee80211_hw **hwsim_radios;
static int hwsim_radio_count;
static struct net_device *hwsim_mon; /* global monitor netdev */
static const struct ieee80211_channel hwsim_channels[] = {
{ .center_freq = 2412 },
{ .center_freq = 2417 },
{ .center_freq = 2422 },
{ .center_freq = 2427 },
{ .center_freq = 2432 },
{ .center_freq = 2437 },
{ .center_freq = 2442 },
{ .center_freq = 2447 },
{ .center_freq = 2452 },
{ .center_freq = 2457 },
{ .center_freq = 2462 },
{ .center_freq = 2467 },
{ .center_freq = 2472 },
{ .center_freq = 2484 },
};
static const struct ieee80211_rate hwsim_rates[] = {
{ .bitrate = 10 },
{ .bitrate = 20, .flags = IEEE80211_RATE_SHORT_PREAMBLE },
{ .bitrate = 55, .flags = IEEE80211_RATE_SHORT_PREAMBLE },
{ .bitrate = 110, .flags = IEEE80211_RATE_SHORT_PREAMBLE },
{ .bitrate = 60 },
{ .bitrate = 90 },
{ .bitrate = 120 },
{ .bitrate = 180 },
{ .bitrate = 240 },
{ .bitrate = 360 },
{ .bitrate = 480 },
{ .bitrate = 540 }
};
struct mac80211_hwsim_data {
struct device *dev;
struct ieee80211_supported_band band;
struct ieee80211_channel channels[ARRAY_SIZE(hwsim_channels)];
struct ieee80211_rate rates[ARRAY_SIZE(hwsim_rates)];
struct ieee80211_channel *channel;
int radio_enabled;
unsigned long beacon_int; /* in jiffies unit */
unsigned int rx_filter;
int started;
struct timer_list beacon_timer;
};
struct hwsim_radiotap_hdr {
struct ieee80211_radiotap_header hdr;
u8 rt_flags;
u8 rt_rate;
__le16 rt_channel;
__le16 rt_chbitmask;
} __attribute__ ((packed));
static int hwsim_mon_xmit(struct sk_buff *skb, struct net_device *dev)
{
/* TODO: allow packet injection */
dev_kfree_skb(skb);
return 0;
}
static void mac80211_hwsim_monitor_rx(struct ieee80211_hw *hw,
struct sk_buff *tx_skb)
{
struct mac80211_hwsim_data *data = hw->priv;
struct sk_buff *skb;
struct hwsim_radiotap_hdr *hdr;
u16 flags;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx_skb);
struct ieee80211_rate *txrate = ieee80211_get_tx_rate(hw, info);
if (!netif_running(hwsim_mon))
return;
skb = skb_copy_expand(tx_skb, sizeof(*hdr), 0, GFP_ATOMIC);
if (skb == NULL)
return;
hdr = (struct hwsim_radiotap_hdr *) skb_push(skb, sizeof(*hdr));
hdr->hdr.it_version = PKTHDR_RADIOTAP_VERSION;
hdr->hdr.it_pad = 0;
hdr->hdr.it_len = cpu_to_le16(sizeof(*hdr));
hdr->hdr.it_present = __constant_cpu_to_le32(
(1 << IEEE80211_RADIOTAP_FLAGS) |
(1 << IEEE80211_RADIOTAP_RATE) |
(1 << IEEE80211_RADIOTAP_CHANNEL));
hdr->rt_flags = 0;
hdr->rt_rate = txrate->bitrate / 5;
hdr->rt_channel = data->channel->center_freq;
flags = IEEE80211_CHAN_2GHZ;
if (txrate->flags & IEEE80211_RATE_ERP_G)
flags |= IEEE80211_CHAN_OFDM;
else
flags |= IEEE80211_CHAN_CCK;
hdr->rt_chbitmask = cpu_to_le16(flags);
skb->dev = hwsim_mon;
skb_set_mac_header(skb, 0);
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->pkt_type = PACKET_OTHERHOST;
skb->protocol = __constant_htons(ETH_P_802_2);
memset(skb->cb, 0, sizeof(skb->cb));
netif_rx(skb);
}
static int mac80211_hwsim_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
{
struct mac80211_hwsim_data *data = hw->priv;
struct ieee80211_rx_status rx_status;
int i, ack = 0;
struct ieee80211_hdr *hdr;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_tx_info *txi;
mac80211_hwsim_monitor_rx(hw, skb);
if (skb->len < 10) {
/* Should not happen; just a sanity check for addr1 use */
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
if (!data->radio_enabled) {
printk(KERN_DEBUG "%s: dropped TX frame since radio "
"disabled\n", wiphy_name(hw->wiphy));
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
hdr = (struct ieee80211_hdr *) skb->data;
memset(&rx_status, 0, sizeof(rx_status));
/* TODO: set mactime */
rx_status.freq = data->channel->center_freq;
rx_status.band = data->channel->band;
rx_status.rate_idx = info->tx_rate_idx;
/* TODO: simulate signal strength (and optional packet drop) */
/* Copy skb to all enabled radios that are on the current frequency */
for (i = 0; i < hwsim_radio_count; i++) {
struct mac80211_hwsim_data *data2;
struct sk_buff *nskb;
if (hwsim_radios[i] == NULL || hwsim_radios[i] == hw)
continue;
data2 = hwsim_radios[i]->priv;
if (!data2->started || !data2->radio_enabled ||
data->channel->center_freq != data2->channel->center_freq)
continue;
nskb = skb_copy(skb, GFP_ATOMIC);
if (nskb == NULL)
continue;
if (memcmp(hdr->addr1, hwsim_radios[i]->wiphy->perm_addr,
ETH_ALEN) == 0)
ack = 1;
ieee80211_rx_irqsafe(hwsim_radios[i], nskb, &rx_status);
}
txi = IEEE80211_SKB_CB(skb);
memset(&txi->status, 0, sizeof(txi->status));
if (!(txi->flags & IEEE80211_TX_CTL_NO_ACK)) {
if (ack)
txi->flags |= IEEE80211_TX_STAT_ACK;
else
txi->status.excessive_retries = 1;
}
ieee80211_tx_status_irqsafe(hw, skb);
return NETDEV_TX_OK;
}
static int mac80211_hwsim_start(struct ieee80211_hw *hw)
{
struct mac80211_hwsim_data *data = hw->priv;
printk(KERN_DEBUG "%s:%s\n", wiphy_name(hw->wiphy), __func__);
data->started = 1;
return 0;
}
static void mac80211_hwsim_stop(struct ieee80211_hw *hw)
{
struct mac80211_hwsim_data *data = hw->priv;
data->started = 0;
printk(KERN_DEBUG "%s:%s\n", wiphy_name(hw->wiphy), __func__);
}
static int mac80211_hwsim_add_interface(struct ieee80211_hw *hw,
struct ieee80211_if_init_conf *conf)
{
DECLARE_MAC_BUF(mac);
printk(KERN_DEBUG "%s:%s (type=%d mac_addr=%s)\n",
wiphy_name(hw->wiphy), __func__, conf->type,
print_mac(mac, conf->mac_addr));
return 0;
}
static void mac80211_hwsim_remove_interface(
struct ieee80211_hw *hw, struct ieee80211_if_init_conf *conf)
{
DECLARE_MAC_BUF(mac);
printk(KERN_DEBUG "%s:%s (type=%d mac_addr=%s)\n",
wiphy_name(hw->wiphy), __func__, conf->type,
print_mac(mac, conf->mac_addr));
}
static void mac80211_hwsim_beacon_tx(void *arg, u8 *mac,
struct ieee80211_vif *vif)
{
struct ieee80211_hw *hw = arg;
struct mac80211_hwsim_data *data = hw->priv;
struct sk_buff *skb;
struct ieee80211_rx_status rx_status;
int i;
struct ieee80211_tx_info *info;
if (vif->type != IEEE80211_IF_TYPE_AP)
return;
skb = ieee80211_beacon_get(hw, vif);
if (skb == NULL)
return;
info = IEEE80211_SKB_CB(skb);
mac80211_hwsim_monitor_rx(hw, skb);
memset(&rx_status, 0, sizeof(rx_status));
/* TODO: set mactime */
rx_status.freq = data->channel->center_freq;
rx_status.band = data->channel->band;
rx_status.rate_idx = info->tx_rate_idx;
/* TODO: simulate signal strength (and optional packet drop) */
/* Copy skb to all enabled radios that are on the current frequency */
for (i = 0; i < hwsim_radio_count; i++) {
struct mac80211_hwsim_data *data2;
struct sk_buff *nskb;
if (hwsim_radios[i] == NULL || hwsim_radios[i] == hw)
continue;
data2 = hwsim_radios[i]->priv;
if (!data2->started || !data2->radio_enabled ||
data->channel->center_freq != data2->channel->center_freq)
continue;
nskb = skb_copy(skb, GFP_ATOMIC);
if (nskb == NULL)
continue;
ieee80211_rx_irqsafe(hwsim_radios[i], nskb, &rx_status);
}
dev_kfree_skb(skb);
}
static void mac80211_hwsim_beacon(unsigned long arg)
{
struct ieee80211_hw *hw = (struct ieee80211_hw *) arg;
struct mac80211_hwsim_data *data = hw->priv;
if (!data->started || !data->radio_enabled)
return;
ieee80211_iterate_active_interfaces(hw, mac80211_hwsim_beacon_tx, hw);
data->beacon_timer.expires = jiffies + data->beacon_int;
add_timer(&data->beacon_timer);
}
static int mac80211_hwsim_config(struct ieee80211_hw *hw,
struct ieee80211_conf *conf)
{
struct mac80211_hwsim_data *data = hw->priv;
printk(KERN_DEBUG "%s:%s (freq=%d radio_enabled=%d beacon_int=%d)\n",
wiphy_name(hw->wiphy), __func__,
conf->channel->center_freq, conf->radio_enabled,
conf->beacon_int);
data->channel = conf->channel;
data->radio_enabled = conf->radio_enabled;
data->beacon_int = 1024 * conf->beacon_int / 1000 * HZ / 1000;
if (data->beacon_int < 1)
data->beacon_int = 1;
if (!data->started || !data->radio_enabled)
del_timer(&data->beacon_timer);
else
mod_timer(&data->beacon_timer, jiffies + data->beacon_int);
return 0;
}
static void mac80211_hwsim_configure_filter(struct ieee80211_hw *hw,
unsigned int changed_flags,
unsigned int *total_flags,
int mc_count,
struct dev_addr_list *mc_list)
{
struct mac80211_hwsim_data *data = hw->priv;
printk(KERN_DEBUG "%s:%s\n", wiphy_name(hw->wiphy), __func__);
data->rx_filter = 0;
if (*total_flags & FIF_PROMISC_IN_BSS)
data->rx_filter |= FIF_PROMISC_IN_BSS;
if (*total_flags & FIF_ALLMULTI)
data->rx_filter |= FIF_ALLMULTI;
*total_flags = data->rx_filter;
}
static const struct ieee80211_ops mac80211_hwsim_ops =
{
.tx = mac80211_hwsim_tx,
.start = mac80211_hwsim_start,
.stop = mac80211_hwsim_stop,
.add_interface = mac80211_hwsim_add_interface,
.remove_interface = mac80211_hwsim_remove_interface,
.config = mac80211_hwsim_config,
.configure_filter = mac80211_hwsim_configure_filter,
};
static void mac80211_hwsim_free(void)
{
int i;
for (i = 0; i < hwsim_radio_count; i++) {
if (hwsim_radios[i]) {
struct mac80211_hwsim_data *data;
data = hwsim_radios[i]->priv;
ieee80211_unregister_hw(hwsim_radios[i]);
if (!IS_ERR(data->dev))
device_unregister(data->dev);
ieee80211_free_hw(hwsim_radios[i]);
}
}
kfree(hwsim_radios);
class_destroy(hwsim_class);
}
static struct device_driver mac80211_hwsim_driver = {
.name = "mac80211_hwsim"
};
static void hwsim_mon_setup(struct net_device *dev)
{
dev->hard_start_xmit = hwsim_mon_xmit;
dev->destructor = free_netdev;
ether_setup(dev);
dev->tx_queue_len = 0;
dev->type = ARPHRD_IEEE80211_RADIOTAP;
memset(dev->dev_addr, 0, ETH_ALEN);
dev->dev_addr[0] = 0x12;
}
static int __init init_mac80211_hwsim(void)
{
int i, err = 0;
u8 addr[ETH_ALEN];
struct mac80211_hwsim_data *data;
struct ieee80211_hw *hw;
DECLARE_MAC_BUF(mac);
if (radios < 1 || radios > 65535)
return -EINVAL;
hwsim_radio_count = radios;
hwsim_radios = kcalloc(hwsim_radio_count,
sizeof(struct ieee80211_hw *), GFP_KERNEL);
if (hwsim_radios == NULL)
return -ENOMEM;
hwsim_class = class_create(THIS_MODULE, "mac80211_hwsim");
if (IS_ERR(hwsim_class)) {
kfree(hwsim_radios);
return PTR_ERR(hwsim_class);
}
memset(addr, 0, ETH_ALEN);
addr[0] = 0x02;
for (i = 0; i < hwsim_radio_count; i++) {
printk(KERN_DEBUG "mac80211_hwsim: Initializing radio %d\n",
i);
hw = ieee80211_alloc_hw(sizeof(*data), &mac80211_hwsim_ops);
if (hw == NULL) {
printk(KERN_DEBUG "mac80211_hwsim: ieee80211_alloc_hw "
"failed\n");
err = -ENOMEM;
goto failed;
}
hwsim_radios[i] = hw;
data = hw->priv;
data->dev = device_create(hwsim_class, NULL, 0, "hwsim%d", i);
if (IS_ERR(data->dev)) {
printk(KERN_DEBUG "mac80211_hwsim: device_create "
"failed (%ld)\n", PTR_ERR(data->dev));
err = -ENOMEM;
goto failed;
}
data->dev->driver = &mac80211_hwsim_driver;
dev_set_drvdata(data->dev, hw);
SET_IEEE80211_DEV(hw, data->dev);
addr[3] = i >> 8;
addr[4] = i;
SET_IEEE80211_PERM_ADDR(hw, addr);
hw->channel_change_time = 1;
hw->queues = 1;
memcpy(data->channels, hwsim_channels, sizeof(hwsim_channels));
memcpy(data->rates, hwsim_rates, sizeof(hwsim_rates));
data->band.channels = data->channels;
data->band.n_channels = ARRAY_SIZE(hwsim_channels);
data->band.bitrates = data->rates;
data->band.n_bitrates = ARRAY_SIZE(hwsim_rates);
hw->wiphy->bands[IEEE80211_BAND_2GHZ] = &data->band;
err = ieee80211_register_hw(hw);
if (err < 0) {
printk(KERN_DEBUG "mac80211_hwsim: "
"ieee80211_register_hw failed (%d)\n", err);
goto failed;
}
printk(KERN_DEBUG "%s: hwaddr %s registered\n",
wiphy_name(hw->wiphy),
print_mac(mac, hw->wiphy->perm_addr));
setup_timer(&data->beacon_timer, mac80211_hwsim_beacon,
(unsigned long) hw);
}
hwsim_mon = alloc_netdev(0, "hwsim%d", hwsim_mon_setup);
if (hwsim_mon == NULL)
goto failed;
rtnl_lock();
err = dev_alloc_name(hwsim_mon, hwsim_mon->name);
if (err < 0) {
goto failed_mon;
}
err = register_netdevice(hwsim_mon);
if (err < 0)
goto failed_mon;
rtnl_unlock();
return 0;
failed_mon:
rtnl_unlock();
free_netdev(hwsim_mon);
failed:
mac80211_hwsim_free();
return err;
}
static void __exit exit_mac80211_hwsim(void)
{
printk(KERN_DEBUG "mac80211_hwsim: unregister %d radios\n",
hwsim_radio_count);
unregister_netdev(hwsim_mon);
mac80211_hwsim_free();
}
module_init(init_mac80211_hwsim);
module_exit(exit_mac80211_hwsim);