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>

1 files changed, 533 insertions, 0 deletions

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
new file mode 100644
index 000000000000..3e33b29a4fc9
--- /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);