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>
diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
new file mode 100644
index 0000000..3e33b29
--- /dev/null
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -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);