drivers/net/wireless/virt_wifi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* drivers/net/wireless/virt_wifi.c
   3  *
   4  * A fake implementation of cfg80211_ops that can be tacked on to an ethernet
   5  * net_device to make it appear as a wireless connection.
   6  *
   7  * Copyright (C) 2018 Google, Inc.
   8  *
   9  * Author: schuffelen@google.com
  10  */
  11
  12 #include <net/cfg80211.h>
  13 #include <net/rtnetlink.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/math64.h>
  16 #include <linux/module.h>
  17
  18 static struct wiphy *common_wiphy;
  19
  20 struct virt_wifi_wiphy_priv {
  21         struct delayed_work scan_result;
  22         struct cfg80211_scan_request *scan_request;
  23         bool being_deleted;
  24 };
  25
  26 static struct ieee80211_channel channel_2ghz = {
  27         .band = NL80211_BAND_2GHZ,
  28         .center_freq = 2432,
  29         .hw_value = 2432,
  30         .max_power = 20,
  31 };
  32
  33 static struct ieee80211_rate bitrates_2ghz[] = {
  34         { .bitrate = 10 },
  35         { .bitrate = 20 },
  36         { .bitrate = 55 },
  37         { .bitrate = 110 },
  38         { .bitrate = 60 },
  39         { .bitrate = 120 },
  40         { .bitrate = 240 },
  41 };
  42
  43 static struct ieee80211_supported_band band_2ghz = {
  44         .channels = &channel_2ghz,
  45         .bitrates = bitrates_2ghz,
  46         .band = NL80211_BAND_2GHZ,
  47         .n_channels = 1,
  48         .n_bitrates = ARRAY_SIZE(bitrates_2ghz),
  49         .ht_cap = {
  50                 .ht_supported = true,
  51                 .cap = IEEE80211_HT_CAP_SUP_WIDTH_20_40 |
  52                        IEEE80211_HT_CAP_GRN_FLD |
  53                        IEEE80211_HT_CAP_SGI_20 |
  54                        IEEE80211_HT_CAP_SGI_40 |
  55                        IEEE80211_HT_CAP_DSSSCCK40,
  56                 .ampdu_factor = 0x3,
  57                 .ampdu_density = 0x6,
  58                 .mcs = {
  59                         .rx_mask = {0xff, 0xff},
  60                         .tx_params = IEEE80211_HT_MCS_TX_DEFINED,
  61                 },
  62         },
  63 };
  64
  65 static struct ieee80211_channel channel_5ghz = {
  66         .band = NL80211_BAND_5GHZ,
  67         .center_freq = 5240,
  68         .hw_value = 5240,
  69         .max_power = 20,
  70 };
  71
  72 static struct ieee80211_rate bitrates_5ghz[] = {
  73         { .bitrate = 60 },
  74         { .bitrate = 120 },
  75         { .bitrate = 240 },
  76 };
  77
  78 #define RX_MCS_MAP (IEEE80211_VHT_MCS_SUPPORT_0_9 << 0 | \
  79                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 2 | \
  80                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 4 | \
  81                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 6 | \
  82                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 8 | \
  83                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 10 | \
  84                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 12 | \
  85                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 14)
  86
  87 #define TX_MCS_MAP (IEEE80211_VHT_MCS_SUPPORT_0_9 << 0 | \
  88                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 2 | \
  89                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 4 | \
  90                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 6 | \
  91                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 8 | \
  92                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 10 | \
  93                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 12 | \
  94                     IEEE80211_VHT_MCS_SUPPORT_0_9 << 14)
  95
  96 static struct ieee80211_supported_band band_5ghz = {
  97         .channels = &channel_5ghz,
  98         .bitrates = bitrates_5ghz,
  99         .band = NL80211_BAND_5GHZ,
 100         .n_channels = 1,
 101         .n_bitrates = ARRAY_SIZE(bitrates_5ghz),
 102         .ht_cap = {
 103                 .ht_supported = true,
 104                 .cap = IEEE80211_HT_CAP_SUP_WIDTH_20_40 |
 105                        IEEE80211_HT_CAP_GRN_FLD |
 106                        IEEE80211_HT_CAP_SGI_20 |
 107                        IEEE80211_HT_CAP_SGI_40 |
 108                        IEEE80211_HT_CAP_DSSSCCK40,
 109                 .ampdu_factor = 0x3,
 110                 .ampdu_density = 0x6,
 111                 .mcs = {
 112                         .rx_mask = {0xff, 0xff},
 113                         .tx_params = IEEE80211_HT_MCS_TX_DEFINED,
 114                 },
 115         },
 116         .vht_cap = {
 117                 .vht_supported = true,
 118                 .cap = IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_11454 |
 119                        IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ |
 120                        IEEE80211_VHT_CAP_RXLDPC |
 121                        IEEE80211_VHT_CAP_SHORT_GI_80 |
 122                        IEEE80211_VHT_CAP_SHORT_GI_160 |
 123                        IEEE80211_VHT_CAP_TXSTBC |
 124                        IEEE80211_VHT_CAP_RXSTBC_1 |
 125                        IEEE80211_VHT_CAP_RXSTBC_2 |
 126                        IEEE80211_VHT_CAP_RXSTBC_3 |
 127                        IEEE80211_VHT_CAP_RXSTBC_4 |
 128                        IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK,
 129                 .vht_mcs = {
 130                         .rx_mcs_map = cpu_to_le16(RX_MCS_MAP),
 131                         .tx_mcs_map = cpu_to_le16(TX_MCS_MAP),
 132                 }
 133         },
 134 };
 135
 136 /* Assigned at module init. Guaranteed locally-administered and unicast. */
 137 static u8 fake_router_bssid[ETH_ALEN] __ro_after_init = {};
 138
 139 /* Called with the rtnl lock held. */
 140 static int virt_wifi_scan(struct wiphy *wiphy,
 141                           struct cfg80211_scan_request *request)
 142 {
 143         struct virt_wifi_wiphy_priv *priv = wiphy_priv(wiphy);
 144
 145         wiphy_debug(wiphy, "scan\n");
 146
 147         if (priv->scan_request || priv->being_deleted)
 148                 return -EBUSY;
 149
 150         priv->scan_request = request;
 151         schedule_delayed_work(&priv->scan_result, HZ * 2);
 152
 153         return 0;
 154 }
 155
 156 /* Acquires and releases the rdev BSS lock. */
 157 static void virt_wifi_scan_result(struct work_struct *work)
 158 {
 159         struct {
 160                 u8 tag;
 161                 u8 len;
 162                 u8 ssid[8];
 163         } __packed ssid = {
 164                 .tag = WLAN_EID_SSID, .len = 8, .ssid = "VirtWifi",
 165         };
 166         struct cfg80211_bss *informed_bss;
 167         struct virt_wifi_wiphy_priv *priv =
 168                 container_of(work, struct virt_wifi_wiphy_priv,
 169                              scan_result.work);
 170         struct wiphy *wiphy = priv_to_wiphy(priv);
 171         struct cfg80211_scan_info scan_info = { .aborted = false };
 172         u64 tsf = div_u64(ktime_get_boottime_ns(), 1000);
 173
 174         informed_bss = cfg80211_inform_bss(wiphy, &channel_5ghz,
 175                                            CFG80211_BSS_FTYPE_PRESP,
 176                                            fake_router_bssid, tsf,
 177                                            WLAN_CAPABILITY_ESS, 0,
 178                                            (void *)&ssid, sizeof(ssid),
 179                                            DBM_TO_MBM(-50), GFP_KERNEL);
 180         cfg80211_put_bss(wiphy, informed_bss);
 181
 182         /* Schedules work which acquires and releases the rtnl lock. */
 183         cfg80211_scan_done(priv->scan_request, &scan_info);
 184         priv->scan_request = NULL;
 185 }
 186
 187 /* May acquire and release the rdev BSS lock. */
 188 static void virt_wifi_cancel_scan(struct wiphy *wiphy)
 189 {
 190         struct virt_wifi_wiphy_priv *priv = wiphy_priv(wiphy);
 191
 192         cancel_delayed_work_sync(&priv->scan_result);
 193         /* Clean up dangling callbacks if necessary. */
 194         if (priv->scan_request) {
 195                 struct cfg80211_scan_info scan_info = { .aborted = true };
 196                 /* Schedules work which acquires and releases the rtnl lock. */
 197                 cfg80211_scan_done(priv->scan_request, &scan_info);
 198                 priv->scan_request = NULL;
 199         }
 200 }
 201
 202 struct virt_wifi_netdev_priv {
 203         struct delayed_work connect;
 204         struct net_device *lowerdev;
 205         struct net_device *upperdev;
 206         u32 tx_packets;
 207         u32 tx_failed;
 208         u8 connect_requested_bss[ETH_ALEN];
 209         bool is_up;
 210         bool is_connected;
 211         bool being_deleted;
 212 };
 213
 214 /* Called with the rtnl lock held. */
 215 static int virt_wifi_connect(struct wiphy *wiphy, struct net_device *netdev,
 216                              struct cfg80211_connect_params *sme)
 217 {
 218         struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
 219         bool could_schedule;
 220
 221         if (priv->being_deleted || !priv->is_up)
 222                 return -EBUSY;
 223
 224         could_schedule = schedule_delayed_work(&priv->connect, HZ * 2);
 225         if (!could_schedule)
 226                 return -EBUSY;
 227
 228         if (sme->bssid)
 229                 ether_addr_copy(priv->connect_requested_bss, sme->bssid);
 230         else
 231                 eth_zero_addr(priv->connect_requested_bss);
 232
 233         wiphy_debug(wiphy, "connect\n");
 234
 235         return 0;
 236 }
 237
 238 /* Acquires and releases the rdev event lock. */
 239 static void virt_wifi_connect_complete(struct work_struct *work)
 240 {
 241         struct virt_wifi_netdev_priv *priv =
 242                 container_of(work, struct virt_wifi_netdev_priv, connect.work);
 243         u8 *requested_bss = priv->connect_requested_bss;
 244         bool has_addr = !is_zero_ether_addr(requested_bss);
 245         bool right_addr = ether_addr_equal(requested_bss, fake_router_bssid);
 246         u16 status = WLAN_STATUS_SUCCESS;
 247
 248         if (!priv->is_up || (has_addr && !right_addr))
 249                 status = WLAN_STATUS_UNSPECIFIED_FAILURE;
 250         else
 251                 priv->is_connected = true;
 252
 253         /* Schedules an event that acquires the rtnl lock. */
 254         cfg80211_connect_result(priv->upperdev, requested_bss, NULL, 0, NULL, 0,
 255                                 status, GFP_KERNEL);
 256         netif_carrier_on(priv->upperdev);
 257 }
 258
 259 /* May acquire and release the rdev event lock. */
 260 static void virt_wifi_cancel_connect(struct net_device *netdev)
 261 {
 262         struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
 263
 264         /* If there is work pending, clean up dangling callbacks. */
 265         if (cancel_delayed_work_sync(&priv->connect)) {
 266                 /* Schedules an event that acquires the rtnl lock. */
 267                 cfg80211_connect_result(priv->upperdev,
 268                                         priv->connect_requested_bss, NULL, 0,
 269                                         NULL, 0,
 270                                         WLAN_STATUS_UNSPECIFIED_FAILURE,
 271                                         GFP_KERNEL);
 272         }
 273 }
 274
 275 /* Called with the rtnl lock held. Acquires the rdev event lock. */
 276 static int virt_wifi_disconnect(struct wiphy *wiphy, struct net_device *netdev,
 277                                 u16 reason_code)
 278 {
 279         struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
 280
 281         if (priv->being_deleted)
 282                 return -EBUSY;
 283
 284         wiphy_debug(wiphy, "disconnect\n");
 285         virt_wifi_cancel_connect(netdev);
 286
 287         cfg80211_disconnected(netdev, reason_code, NULL, 0, true, GFP_KERNEL);
 288         priv->is_connected = false;
 289         netif_carrier_off(netdev);
 290
 291         return 0;
 292 }
 293
 294 /* Called with the rtnl lock held. */
 295 static int virt_wifi_get_station(struct wiphy *wiphy, struct net_device *dev,
 296                                  const u8 *mac, struct station_info *sinfo)
 297 {
 298         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 299
 300         wiphy_debug(wiphy, "get_station\n");
 301
 302         if (!priv->is_connected || !ether_addr_equal(mac, fake_router_bssid))
 303                 return -ENOENT;
 304
 305         sinfo->filled = BIT_ULL(NL80211_STA_INFO_TX_PACKETS) |
 306                 BIT_ULL(NL80211_STA_INFO_TX_FAILED) |
 307                 BIT_ULL(NL80211_STA_INFO_SIGNAL) |
 308                 BIT_ULL(NL80211_STA_INFO_TX_BITRATE);
 309         sinfo->tx_packets = priv->tx_packets;
 310         sinfo->tx_failed = priv->tx_failed;
 311         /* For CFG80211_SIGNAL_TYPE_MBM, value is expressed in _dBm_ */
 312         sinfo->signal = -50;
 313         sinfo->txrate = (struct rate_info) {
 314                 .legacy = 10, /* units are 100kbit/s */
 315         };
 316         return 0;
 317 }
 318
 319 /* Called with the rtnl lock held. */
 320 static int virt_wifi_dump_station(struct wiphy *wiphy, struct net_device *dev,
 321                                   int idx, u8 *mac, struct station_info *sinfo)
 322 {
 323         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 324
 325         wiphy_debug(wiphy, "dump_station\n");
 326
 327         if (idx != 0 || !priv->is_connected)
 328                 return -ENOENT;
 329
 330         ether_addr_copy(mac, fake_router_bssid);
 331         return virt_wifi_get_station(wiphy, dev, fake_router_bssid, sinfo);
 332 }
 333
 334 static const struct cfg80211_ops virt_wifi_cfg80211_ops = {
 335         .scan = virt_wifi_scan,
 336
 337         .connect = virt_wifi_connect,
 338         .disconnect = virt_wifi_disconnect,
 339
 340         .get_station = virt_wifi_get_station,
 341         .dump_station = virt_wifi_dump_station,
 342 };
 343
 344 /* Acquires and releases the rtnl lock. */
 345 static struct wiphy *virt_wifi_make_wiphy(void)
 346 {
 347         struct wiphy *wiphy;
 348         struct virt_wifi_wiphy_priv *priv;
 349         int err;
 350
 351         wiphy = wiphy_new(&virt_wifi_cfg80211_ops, sizeof(*priv));
 352
 353         if (!wiphy)
 354                 return NULL;
 355
 356         wiphy->max_scan_ssids = 4;
 357         wiphy->max_scan_ie_len = 1000;
 358         wiphy->signal_type = CFG80211_SIGNAL_TYPE_MBM;
 359
 360         wiphy->bands[NL80211_BAND_2GHZ] = &band_2ghz;
 361         wiphy->bands[NL80211_BAND_5GHZ] = &band_5ghz;
 362         wiphy->bands[NL80211_BAND_60GHZ] = NULL;
 363
 364         wiphy->interface_modes = BIT(NL80211_IFTYPE_STATION);
 365
 366         priv = wiphy_priv(wiphy);
 367         priv->being_deleted = false;
 368         priv->scan_request = NULL;
 369         INIT_DELAYED_WORK(&priv->scan_result, virt_wifi_scan_result);
 370
 371         err = wiphy_register(wiphy);
 372         if (err < 0) {
 373                 wiphy_free(wiphy);
 374                 return NULL;
 375         }
 376
 377         return wiphy;
 378 }
 379
 380 /* Acquires and releases the rtnl lock. */
 381 static void virt_wifi_destroy_wiphy(struct wiphy *wiphy)
 382 {
 383         struct virt_wifi_wiphy_priv *priv;
 384
 385         WARN(!wiphy, "%s called with null wiphy", __func__);
 386         if (!wiphy)
 387                 return;
 388
 389         priv = wiphy_priv(wiphy);
 390         priv->being_deleted = true;
 391         virt_wifi_cancel_scan(wiphy);
 392
 393         if (wiphy->registered)
 394                 wiphy_unregister(wiphy);
 395         wiphy_free(wiphy);
 396 }
 397
 398 /* Enters and exits a RCU-bh critical section. */
 399 static netdev_tx_t virt_wifi_start_xmit(struct sk_buff *skb,
 400                                         struct net_device *dev)
 401 {
 402         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 403
 404         priv->tx_packets++;
 405         if (!priv->is_connected) {
 406                 priv->tx_failed++;
 407                 return NET_XMIT_DROP;
 408         }
 409
 410         skb->dev = priv->lowerdev;
 411         return dev_queue_xmit(skb);
 412 }
 413
 414 /* Called with rtnl lock held. */
 415 static int virt_wifi_net_device_open(struct net_device *dev)
 416 {
 417         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 418
 419         priv->is_up = true;
 420         return 0;
 421 }
 422
 423 /* Called with rtnl lock held. */
 424 static int virt_wifi_net_device_stop(struct net_device *dev)
 425 {
 426         struct virt_wifi_netdev_priv *n_priv = netdev_priv(dev);
 427
 428         n_priv->is_up = false;
 429
 430         if (!dev->ieee80211_ptr)
 431                 return 0;
 432
 433         virt_wifi_cancel_scan(dev->ieee80211_ptr->wiphy);
 434         virt_wifi_cancel_connect(dev);
 435         netif_carrier_off(dev);
 436
 437         return 0;
 438 }
 439
 440 static int virt_wifi_net_device_get_iflink(const struct net_device *dev)
 441 {
 442         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 443
 444         return priv->lowerdev->ifindex;
 445 }
 446
 447 static const struct net_device_ops virt_wifi_ops = {
 448         .ndo_start_xmit = virt_wifi_start_xmit,
 449         .ndo_open       = virt_wifi_net_device_open,
 450         .ndo_stop       = virt_wifi_net_device_stop,
 451         .ndo_get_iflink = virt_wifi_net_device_get_iflink,
 452 };
 453
 454 /* Invoked as part of rtnl lock release. */
 455 static void virt_wifi_net_device_destructor(struct net_device *dev)
 456 {
 457         /* Delayed past dellink to allow nl80211 to react to the device being
 458          * deleted.
 459          */
 460         kfree(dev->ieee80211_ptr);
 461         dev->ieee80211_ptr = NULL;
 462 }
 463
 464 /* No lock interaction. */
 465 static void virt_wifi_setup(struct net_device *dev)
 466 {
 467         ether_setup(dev);
 468         dev->netdev_ops = &virt_wifi_ops;
 469         dev->needs_free_netdev  = true;
 470 }
 471
 472 /* Called in a RCU read critical section from netif_receive_skb */
 473 static rx_handler_result_t virt_wifi_rx_handler(struct sk_buff **pskb)
 474 {
 475         struct sk_buff *skb = *pskb;
 476         struct virt_wifi_netdev_priv *priv =
 477                 rcu_dereference(skb->dev->rx_handler_data);
 478
 479         if (!priv->is_connected)
 480                 return RX_HANDLER_PASS;
 481
 482         /* GFP_ATOMIC because this is a packet interrupt handler. */
 483         skb = skb_share_check(skb, GFP_ATOMIC);
 484         if (!skb) {
 485                 dev_err(&priv->upperdev->dev, "can't skb_share_check\n");
 486                 return RX_HANDLER_CONSUMED;
 487         }
 488
 489         *pskb = skb;
 490         skb->dev = priv->upperdev;
 491         skb->pkt_type = PACKET_HOST;
 492         return RX_HANDLER_ANOTHER;
 493 }
 494
 495 /* Called with rtnl lock held. */
 496 static int virt_wifi_newlink(struct net *src_net, struct net_device *dev,
 497                              struct nlattr *tb[], struct nlattr *data[],
 498                              struct netlink_ext_ack *extack)
 499 {
 500         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 501         int err;
 502
 503         if (!tb[IFLA_LINK])
 504                 return -EINVAL;
 505
 506         netif_carrier_off(dev);
 507
 508         priv->upperdev = dev;
 509         priv->lowerdev = __dev_get_by_index(src_net,
 510                                             nla_get_u32(tb[IFLA_LINK]));
 511
 512         if (!priv->lowerdev)
 513                 return -ENODEV;
 514         if (!tb[IFLA_MTU])
 515                 dev->mtu = priv->lowerdev->mtu;
 516         else if (dev->mtu > priv->lowerdev->mtu)
 517                 return -EINVAL;
 518
 519         err = netdev_rx_handler_register(priv->lowerdev, virt_wifi_rx_handler,
 520                                          priv);
 521         if (err) {
 522                 dev_err(&priv->lowerdev->dev,
 523                         "can't netdev_rx_handler_register: %d\n", err);
 524                 return err;
 525         }
 526
 527         eth_hw_addr_inherit(dev, priv->lowerdev);
 528         netif_stacked_transfer_operstate(priv->lowerdev, dev);
 529
 530         SET_NETDEV_DEV(dev, &priv->lowerdev->dev);
 531         dev->ieee80211_ptr = kzalloc(sizeof(*dev->ieee80211_ptr), GFP_KERNEL);
 532
 533         if (!dev->ieee80211_ptr) {
 534                 err = -ENOMEM;
 535                 goto remove_handler;
 536         }
 537
 538         dev->ieee80211_ptr->iftype = NL80211_IFTYPE_STATION;
 539         dev->ieee80211_ptr->wiphy = common_wiphy;
 540
 541         err = register_netdevice(dev);
 542         if (err) {
 543                 dev_err(&priv->lowerdev->dev, "can't register_netdevice: %d\n",
 544                         err);
 545                 goto free_wireless_dev;
 546         }
 547
 548         err = netdev_upper_dev_link(priv->lowerdev, dev, extack);
 549         if (err) {
 550                 dev_err(&priv->lowerdev->dev, "can't netdev_upper_dev_link: %d\n",
 551                         err);
 552                 goto unregister_netdev;
 553         }
 554
 555         dev->priv_destructor = virt_wifi_net_device_destructor;
 556         priv->being_deleted = false;
 557         priv->is_connected = false;
 558         priv->is_up = false;
 559         INIT_DELAYED_WORK(&priv->connect, virt_wifi_connect_complete);
 560         __module_get(THIS_MODULE);
 561
 562         return 0;
 563 unregister_netdev:
 564         unregister_netdevice(dev);
 565 free_wireless_dev:
 566         kfree(dev->ieee80211_ptr);
 567         dev->ieee80211_ptr = NULL;
 568 remove_handler:
 569         netdev_rx_handler_unregister(priv->lowerdev);
 570
 571         return err;
 572 }
 573
 574 /* Called with rtnl lock held. */
 575 static void virt_wifi_dellink(struct net_device *dev,
 576                               struct list_head *head)
 577 {
 578         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 579
 580         if (dev->ieee80211_ptr)
 581                 virt_wifi_cancel_scan(dev->ieee80211_ptr->wiphy);
 582
 583         priv->being_deleted = true;
 584         virt_wifi_cancel_connect(dev);
 585         netif_carrier_off(dev);
 586
 587         netdev_rx_handler_unregister(priv->lowerdev);
 588         netdev_upper_dev_unlink(priv->lowerdev, dev);
 589
 590         unregister_netdevice_queue(dev, head);
 591         module_put(THIS_MODULE);
 592
 593         /* Deleting the wiphy is handled in the module destructor. */
 594 }
 595
 596 static struct rtnl_link_ops virt_wifi_link_ops = {
 597         .kind           = "virt_wifi",
 598         .setup          = virt_wifi_setup,
 599         .newlink        = virt_wifi_newlink,
 600         .dellink        = virt_wifi_dellink,
 601         .priv_size      = sizeof(struct virt_wifi_netdev_priv),
 602 };
 603
 604 static bool netif_is_virt_wifi_dev(const struct net_device *dev)
 605 {
 606         return rcu_access_pointer(dev->rx_handler) == virt_wifi_rx_handler;
 607 }
 608
 609 static int virt_wifi_event(struct notifier_block *this, unsigned long event,
 610                            void *ptr)
 611 {
 612         struct net_device *lower_dev = netdev_notifier_info_to_dev(ptr);
 613         struct virt_wifi_netdev_priv *priv;
 614         struct net_device *upper_dev;
 615         LIST_HEAD(list_kill);
 616
 617         if (!netif_is_virt_wifi_dev(lower_dev))
 618                 return NOTIFY_DONE;
 619
 620         switch (event) {
 621         case NETDEV_UNREGISTER:
 622                 priv = rtnl_dereference(lower_dev->rx_handler_data);
 623                 if (!priv)
 624                         return NOTIFY_DONE;
 625
 626                 upper_dev = priv->upperdev;
 627
 628                 upper_dev->rtnl_link_ops->dellink(upper_dev, &list_kill);
 629                 unregister_netdevice_many(&list_kill);
 630                 break;
 631         }
 632
 633         return NOTIFY_DONE;
 634 }
 635
 636 static struct notifier_block virt_wifi_notifier = {
 637         .notifier_call = virt_wifi_event,
 638 };
 639
 640 /* Acquires and releases the rtnl lock. */
 641 static int __init virt_wifi_init_module(void)
 642 {
 643         int err;
 644
 645         /* Guaranteed to be locallly-administered and not multicast. */
 646         eth_random_addr(fake_router_bssid);
 647
 648         err = register_netdevice_notifier(&virt_wifi_notifier);
 649         if (err)
 650                 return err;
 651
 652         err = -ENOMEM;
 653         common_wiphy = virt_wifi_make_wiphy();
 654         if (!common_wiphy)
 655                 goto notifier;
 656
 657         err = rtnl_link_register(&virt_wifi_link_ops);
 658         if (err)
 659                 goto destroy_wiphy;
 660
 661         return 0;
 662
 663 destroy_wiphy:
 664         virt_wifi_destroy_wiphy(common_wiphy);
 665 notifier:
 666         unregister_netdevice_notifier(&virt_wifi_notifier);
 667         return err;
 668 }
 669
 670 /* Acquires and releases the rtnl lock. */
 671 static void __exit virt_wifi_cleanup_module(void)
 672 {
 673         /* Will delete any devices that depend on the wiphy. */
 674         rtnl_link_unregister(&virt_wifi_link_ops);
 675         virt_wifi_destroy_wiphy(common_wiphy);
 676         unregister_netdevice_notifier(&virt_wifi_notifier);
 677 }
 678
 679 module_init(virt_wifi_init_module);
 680 module_exit(virt_wifi_cleanup_module);
 681
 682 MODULE_LICENSE("GPL v2");
 683 MODULE_AUTHOR("Cody Schuffelen <schuffelen@google.com>");
 684 MODULE_DESCRIPTION("Driver for a wireless wrapper of ethernet devices");
 685 MODULE_ALIAS_RTNL_LINK("virt_wifi");