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 static void virt_wifi_inform_bss(struct wiphy *wiphy)
 140 {
 141         u64 tsf = div_u64(ktime_get_boottime_ns(), 1000);
 142         struct cfg80211_bss *informed_bss;
 143         static const struct {
 144                 u8 tag;
 145                 u8 len;
 146                 u8 ssid[8];
 147         } __packed ssid = {
 148                 .tag = WLAN_EID_SSID,
 149                 .len = 8,
 150                 .ssid = "VirtWifi",
 151         };
 152
 153         informed_bss = cfg80211_inform_bss(wiphy, &channel_5ghz,
 154                                            CFG80211_BSS_FTYPE_PRESP,
 155                                            fake_router_bssid, tsf,
 156                                            WLAN_CAPABILITY_ESS, 0,
 157                                            (void *)&ssid, sizeof(ssid),
 158                                            DBM_TO_MBM(-50), GFP_KERNEL);
 159         cfg80211_put_bss(wiphy, informed_bss);
 160 }
 161
 162 /* Called with the rtnl lock held. */
 163 static int virt_wifi_scan(struct wiphy *wiphy,
 164                           struct cfg80211_scan_request *request)
 165 {
 166         struct virt_wifi_wiphy_priv *priv = wiphy_priv(wiphy);
 167
 168         wiphy_debug(wiphy, "scan\n");
 169
 170         if (priv->scan_request || priv->being_deleted)
 171                 return -EBUSY;
 172
 173         priv->scan_request = request;
 174         schedule_delayed_work(&priv->scan_result, HZ * 2);
 175
 176         return 0;
 177 }
 178
 179 /* Acquires and releases the rdev BSS lock. */
 180 static void virt_wifi_scan_result(struct work_struct *work)
 181 {
 182         struct virt_wifi_wiphy_priv *priv =
 183                 container_of(work, struct virt_wifi_wiphy_priv,
 184                              scan_result.work);
 185         struct wiphy *wiphy = priv_to_wiphy(priv);
 186         struct cfg80211_scan_info scan_info = { .aborted = false };
 187
 188         virt_wifi_inform_bss(wiphy);
 189
 190         /* Schedules work which acquires and releases the rtnl lock. */
 191         cfg80211_scan_done(priv->scan_request, &scan_info);
 192         priv->scan_request = NULL;
 193 }
 194
 195 /* May acquire and release the rdev BSS lock. */
 196 static void virt_wifi_cancel_scan(struct wiphy *wiphy)
 197 {
 198         struct virt_wifi_wiphy_priv *priv = wiphy_priv(wiphy);
 199
 200         cancel_delayed_work_sync(&priv->scan_result);
 201         /* Clean up dangling callbacks if necessary. */
 202         if (priv->scan_request) {
 203                 struct cfg80211_scan_info scan_info = { .aborted = true };
 204                 /* Schedules work which acquires and releases the rtnl lock. */
 205                 cfg80211_scan_done(priv->scan_request, &scan_info);
 206                 priv->scan_request = NULL;
 207         }
 208 }
 209
 210 struct virt_wifi_netdev_priv {
 211         struct delayed_work connect;
 212         struct net_device *lowerdev;
 213         struct net_device *upperdev;
 214         u32 tx_packets;
 215         u32 tx_failed;
 216         u8 connect_requested_bss[ETH_ALEN];
 217         bool is_up;
 218         bool is_connected;
 219         bool being_deleted;
 220 };
 221
 222 /* Called with the rtnl lock held. */
 223 static int virt_wifi_connect(struct wiphy *wiphy, struct net_device *netdev,
 224                              struct cfg80211_connect_params *sme)
 225 {
 226         struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
 227         bool could_schedule;
 228
 229         if (priv->being_deleted || !priv->is_up)
 230                 return -EBUSY;
 231
 232         could_schedule = schedule_delayed_work(&priv->connect, HZ * 2);
 233         if (!could_schedule)
 234                 return -EBUSY;
 235
 236         if (sme->bssid) {
 237                 ether_addr_copy(priv->connect_requested_bss, sme->bssid);
 238         } else {
 239                 virt_wifi_inform_bss(wiphy);
 240                 eth_zero_addr(priv->connect_requested_bss);
 241         }
 242
 243         wiphy_debug(wiphy, "connect\n");
 244
 245         return 0;
 246 }
 247
 248 /* Acquires and releases the rdev event lock. */
 249 static void virt_wifi_connect_complete(struct work_struct *work)
 250 {
 251         struct virt_wifi_netdev_priv *priv =
 252                 container_of(work, struct virt_wifi_netdev_priv, connect.work);
 253         u8 *requested_bss = priv->connect_requested_bss;
 254         bool right_addr = ether_addr_equal(requested_bss, fake_router_bssid);
 255         u16 status = WLAN_STATUS_SUCCESS;
 256
 257         if (is_zero_ether_addr(requested_bss))
 258                 requested_bss = NULL;
 259
 260         if (!priv->is_up || (requested_bss && !right_addr))
 261                 status = WLAN_STATUS_UNSPECIFIED_FAILURE;
 262         else
 263                 priv->is_connected = true;
 264
 265         /* Schedules an event that acquires the rtnl lock. */
 266         cfg80211_connect_result(priv->upperdev, requested_bss, NULL, 0, NULL, 0,
 267                                 status, GFP_KERNEL);
 268         netif_carrier_on(priv->upperdev);
 269 }
 270
 271 /* May acquire and release the rdev event lock. */
 272 static void virt_wifi_cancel_connect(struct net_device *netdev)
 273 {
 274         struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
 275
 276         /* If there is work pending, clean up dangling callbacks. */
 277         if (cancel_delayed_work_sync(&priv->connect)) {
 278                 /* Schedules an event that acquires the rtnl lock. */
 279                 cfg80211_connect_result(priv->upperdev,
 280                                         priv->connect_requested_bss, NULL, 0,
 281                                         NULL, 0,
 282                                         WLAN_STATUS_UNSPECIFIED_FAILURE,
 283                                         GFP_KERNEL);
 284         }
 285 }
 286
 287 /* Called with the rtnl lock held. Acquires the rdev event lock. */
 288 static int virt_wifi_disconnect(struct wiphy *wiphy, struct net_device *netdev,
 289                                 u16 reason_code)
 290 {
 291         struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
 292
 293         if (priv->being_deleted)
 294                 return -EBUSY;
 295
 296         wiphy_debug(wiphy, "disconnect\n");
 297         virt_wifi_cancel_connect(netdev);
 298
 299         cfg80211_disconnected(netdev, reason_code, NULL, 0, true, GFP_KERNEL);
 300         priv->is_connected = false;
 301         netif_carrier_off(netdev);
 302
 303         return 0;
 304 }
 305
 306 /* Called with the rtnl lock held. */
 307 static int virt_wifi_get_station(struct wiphy *wiphy, struct net_device *dev,
 308                                  const u8 *mac, struct station_info *sinfo)
 309 {
 310         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 311
 312         wiphy_debug(wiphy, "get_station\n");
 313
 314         if (!priv->is_connected || !ether_addr_equal(mac, fake_router_bssid))
 315                 return -ENOENT;
 316
 317         sinfo->filled = BIT_ULL(NL80211_STA_INFO_TX_PACKETS) |
 318                 BIT_ULL(NL80211_STA_INFO_TX_FAILED) |
 319                 BIT_ULL(NL80211_STA_INFO_SIGNAL) |
 320                 BIT_ULL(NL80211_STA_INFO_TX_BITRATE);
 321         sinfo->tx_packets = priv->tx_packets;
 322         sinfo->tx_failed = priv->tx_failed;
 323         /* For CFG80211_SIGNAL_TYPE_MBM, value is expressed in _dBm_ */
 324         sinfo->signal = -50;
 325         sinfo->txrate = (struct rate_info) {
 326                 .legacy = 10, /* units are 100kbit/s */
 327         };
 328         return 0;
 329 }
 330
 331 /* Called with the rtnl lock held. */
 332 static int virt_wifi_dump_station(struct wiphy *wiphy, struct net_device *dev,
 333                                   int idx, u8 *mac, struct station_info *sinfo)
 334 {
 335         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 336
 337         wiphy_debug(wiphy, "dump_station\n");
 338
 339         if (idx != 0 || !priv->is_connected)
 340                 return -ENOENT;
 341
 342         ether_addr_copy(mac, fake_router_bssid);
 343         return virt_wifi_get_station(wiphy, dev, fake_router_bssid, sinfo);
 344 }
 345
 346 static const struct cfg80211_ops virt_wifi_cfg80211_ops = {
 347         .scan = virt_wifi_scan,
 348
 349         .connect = virt_wifi_connect,
 350         .disconnect = virt_wifi_disconnect,
 351
 352         .get_station = virt_wifi_get_station,
 353         .dump_station = virt_wifi_dump_station,
 354 };
 355
 356 /* Acquires and releases the rtnl lock. */
 357 static struct wiphy *virt_wifi_make_wiphy(void)
 358 {
 359         struct wiphy *wiphy;
 360         struct virt_wifi_wiphy_priv *priv;
 361         int err;
 362
 363         wiphy = wiphy_new(&virt_wifi_cfg80211_ops, sizeof(*priv));
 364
 365         if (!wiphy)
 366                 return NULL;
 367
 368         wiphy->max_scan_ssids = 4;
 369         wiphy->max_scan_ie_len = 1000;
 370         wiphy->signal_type = CFG80211_SIGNAL_TYPE_MBM;
 371
 372         wiphy->bands[NL80211_BAND_2GHZ] = &band_2ghz;
 373         wiphy->bands[NL80211_BAND_5GHZ] = &band_5ghz;
 374         wiphy->bands[NL80211_BAND_60GHZ] = NULL;
 375
 376         wiphy->interface_modes = BIT(NL80211_IFTYPE_STATION);
 377
 378         priv = wiphy_priv(wiphy);
 379         priv->being_deleted = false;
 380         priv->scan_request = NULL;
 381         INIT_DELAYED_WORK(&priv->scan_result, virt_wifi_scan_result);
 382
 383         err = wiphy_register(wiphy);
 384         if (err < 0) {
 385                 wiphy_free(wiphy);
 386                 return NULL;
 387         }
 388
 389         return wiphy;
 390 }
 391
 392 /* Acquires and releases the rtnl lock. */
 393 static void virt_wifi_destroy_wiphy(struct wiphy *wiphy)
 394 {
 395         struct virt_wifi_wiphy_priv *priv;
 396
 397         WARN(!wiphy, "%s called with null wiphy", __func__);
 398         if (!wiphy)
 399                 return;
 400
 401         priv = wiphy_priv(wiphy);
 402         priv->being_deleted = true;
 403         virt_wifi_cancel_scan(wiphy);
 404
 405         if (wiphy->registered)
 406                 wiphy_unregister(wiphy);
 407         wiphy_free(wiphy);
 408 }
 409
 410 /* Enters and exits a RCU-bh critical section. */
 411 static netdev_tx_t virt_wifi_start_xmit(struct sk_buff *skb,
 412                                         struct net_device *dev)
 413 {
 414         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 415
 416         priv->tx_packets++;
 417         if (!priv->is_connected) {
 418                 priv->tx_failed++;
 419                 return NET_XMIT_DROP;
 420         }
 421
 422         skb->dev = priv->lowerdev;
 423         return dev_queue_xmit(skb);
 424 }
 425
 426 /* Called with rtnl lock held. */
 427 static int virt_wifi_net_device_open(struct net_device *dev)
 428 {
 429         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 430
 431         priv->is_up = true;
 432         return 0;
 433 }
 434
 435 /* Called with rtnl lock held. */
 436 static int virt_wifi_net_device_stop(struct net_device *dev)
 437 {
 438         struct virt_wifi_netdev_priv *n_priv = netdev_priv(dev);
 439
 440         n_priv->is_up = false;
 441
 442         if (!dev->ieee80211_ptr)
 443                 return 0;
 444
 445         virt_wifi_cancel_scan(dev->ieee80211_ptr->wiphy);
 446         virt_wifi_cancel_connect(dev);
 447         netif_carrier_off(dev);
 448
 449         return 0;
 450 }
 451
 452 static int virt_wifi_net_device_get_iflink(const struct net_device *dev)
 453 {
 454         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 455
 456         return priv->lowerdev->ifindex;
 457 }
 458
 459 static const struct net_device_ops virt_wifi_ops = {
 460         .ndo_start_xmit = virt_wifi_start_xmit,
 461         .ndo_open       = virt_wifi_net_device_open,
 462         .ndo_stop       = virt_wifi_net_device_stop,
 463         .ndo_get_iflink = virt_wifi_net_device_get_iflink,
 464 };
 465
 466 /* Invoked as part of rtnl lock release. */
 467 static void virt_wifi_net_device_destructor(struct net_device *dev)
 468 {
 469         /* Delayed past dellink to allow nl80211 to react to the device being
 470          * deleted.
 471          */
 472         kfree(dev->ieee80211_ptr);
 473         dev->ieee80211_ptr = NULL;
 474 }
 475
 476 /* No lock interaction. */
 477 static void virt_wifi_setup(struct net_device *dev)
 478 {
 479         ether_setup(dev);
 480         dev->netdev_ops = &virt_wifi_ops;
 481         dev->needs_free_netdev  = true;
 482 }
 483
 484 /* Called in a RCU read critical section from netif_receive_skb */
 485 static rx_handler_result_t virt_wifi_rx_handler(struct sk_buff **pskb)
 486 {
 487         struct sk_buff *skb = *pskb;
 488         struct virt_wifi_netdev_priv *priv =
 489                 rcu_dereference(skb->dev->rx_handler_data);
 490
 491         if (!priv->is_connected)
 492                 return RX_HANDLER_PASS;
 493
 494         /* GFP_ATOMIC because this is a packet interrupt handler. */
 495         skb = skb_share_check(skb, GFP_ATOMIC);
 496         if (!skb) {
 497                 dev_err(&priv->upperdev->dev, "can't skb_share_check\n");
 498                 return RX_HANDLER_CONSUMED;
 499         }
 500
 501         *pskb = skb;
 502         skb->dev = priv->upperdev;
 503         skb->pkt_type = PACKET_HOST;
 504         return RX_HANDLER_ANOTHER;
 505 }
 506
 507 /* Called with rtnl lock held. */
 508 static int virt_wifi_newlink(struct net *src_net, struct net_device *dev,
 509                              struct nlattr *tb[], struct nlattr *data[],
 510                              struct netlink_ext_ack *extack)
 511 {
 512         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 513         int err;
 514
 515         if (!tb[IFLA_LINK])
 516                 return -EINVAL;
 517
 518         netif_carrier_off(dev);
 519
 520         priv->upperdev = dev;
 521         priv->lowerdev = __dev_get_by_index(src_net,
 522                                             nla_get_u32(tb[IFLA_LINK]));
 523
 524         if (!priv->lowerdev)
 525                 return -ENODEV;
 526         if (!tb[IFLA_MTU])
 527                 dev->mtu = priv->lowerdev->mtu;
 528         else if (dev->mtu > priv->lowerdev->mtu)
 529                 return -EINVAL;
 530
 531         err = netdev_rx_handler_register(priv->lowerdev, virt_wifi_rx_handler,
 532                                          priv);
 533         if (err) {
 534                 dev_err(&priv->lowerdev->dev,
 535                         "can't netdev_rx_handler_register: %d\n", err);
 536                 return err;
 537         }
 538
 539         eth_hw_addr_inherit(dev, priv->lowerdev);
 540         netif_stacked_transfer_operstate(priv->lowerdev, dev);
 541
 542         SET_NETDEV_DEV(dev, &priv->lowerdev->dev);
 543         dev->ieee80211_ptr = kzalloc(sizeof(*dev->ieee80211_ptr), GFP_KERNEL);
 544
 545         if (!dev->ieee80211_ptr) {
 546                 err = -ENOMEM;
 547                 goto remove_handler;
 548         }
 549
 550         dev->ieee80211_ptr->iftype = NL80211_IFTYPE_STATION;
 551         dev->ieee80211_ptr->wiphy = common_wiphy;
 552
 553         err = register_netdevice(dev);
 554         if (err) {
 555                 dev_err(&priv->lowerdev->dev, "can't register_netdevice: %d\n",
 556                         err);
 557                 goto free_wireless_dev;
 558         }
 559
 560         err = netdev_upper_dev_link(priv->lowerdev, dev, extack);
 561         if (err) {
 562                 dev_err(&priv->lowerdev->dev, "can't netdev_upper_dev_link: %d\n",
 563                         err);
 564                 goto unregister_netdev;
 565         }
 566
 567         dev->priv_destructor = virt_wifi_net_device_destructor;
 568         priv->being_deleted = false;
 569         priv->is_connected = false;
 570         priv->is_up = false;
 571         INIT_DELAYED_WORK(&priv->connect, virt_wifi_connect_complete);
 572         __module_get(THIS_MODULE);
 573
 574         return 0;
 575 unregister_netdev:
 576         unregister_netdevice(dev);
 577 free_wireless_dev:
 578         kfree(dev->ieee80211_ptr);
 579         dev->ieee80211_ptr = NULL;
 580 remove_handler:
 581         netdev_rx_handler_unregister(priv->lowerdev);
 582
 583         return err;
 584 }
 585
 586 /* Called with rtnl lock held. */
 587 static void virt_wifi_dellink(struct net_device *dev,
 588                               struct list_head *head)
 589 {
 590         struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
 591
 592         if (dev->ieee80211_ptr)
 593                 virt_wifi_cancel_scan(dev->ieee80211_ptr->wiphy);
 594
 595         priv->being_deleted = true;
 596         virt_wifi_cancel_connect(dev);
 597         netif_carrier_off(dev);
 598
 599         netdev_rx_handler_unregister(priv->lowerdev);
 600         netdev_upper_dev_unlink(priv->lowerdev, dev);
 601
 602         unregister_netdevice_queue(dev, head);
 603         module_put(THIS_MODULE);
 604
 605         /* Deleting the wiphy is handled in the module destructor. */
 606 }
 607
 608 static struct rtnl_link_ops virt_wifi_link_ops = {
 609         .kind           = "virt_wifi",
 610         .setup          = virt_wifi_setup,
 611         .newlink        = virt_wifi_newlink,
 612         .dellink        = virt_wifi_dellink,
 613         .priv_size      = sizeof(struct virt_wifi_netdev_priv),
 614 };
 615
 616 static bool netif_is_virt_wifi_dev(const struct net_device *dev)
 617 {
 618         return rcu_access_pointer(dev->rx_handler) == virt_wifi_rx_handler;
 619 }
 620
 621 static int virt_wifi_event(struct notifier_block *this, unsigned long event,
 622                            void *ptr)
 623 {
 624         struct net_device *lower_dev = netdev_notifier_info_to_dev(ptr);
 625         struct virt_wifi_netdev_priv *priv;
 626         struct net_device *upper_dev;
 627         LIST_HEAD(list_kill);
 628
 629         if (!netif_is_virt_wifi_dev(lower_dev))
 630                 return NOTIFY_DONE;
 631
 632         switch (event) {
 633         case NETDEV_UNREGISTER:
 634                 priv = rtnl_dereference(lower_dev->rx_handler_data);
 635                 if (!priv)
 636                         return NOTIFY_DONE;
 637
 638                 upper_dev = priv->upperdev;
 639
 640                 upper_dev->rtnl_link_ops->dellink(upper_dev, &list_kill);
 641                 unregister_netdevice_many(&list_kill);
 642                 break;
 643         }
 644
 645         return NOTIFY_DONE;
 646 }
 647
 648 static struct notifier_block virt_wifi_notifier = {
 649         .notifier_call = virt_wifi_event,
 650 };
 651
 652 /* Acquires and releases the rtnl lock. */
 653 static int __init virt_wifi_init_module(void)
 654 {
 655         int err;
 656
 657         /* Guaranteed to be locallly-administered and not multicast. */
 658         eth_random_addr(fake_router_bssid);
 659
 660         err = register_netdevice_notifier(&virt_wifi_notifier);
 661         if (err)
 662                 return err;
 663
 664         err = -ENOMEM;
 665         common_wiphy = virt_wifi_make_wiphy();
 666         if (!common_wiphy)
 667                 goto notifier;
 668
 669         err = rtnl_link_register(&virt_wifi_link_ops);
 670         if (err)
 671                 goto destroy_wiphy;
 672
 673         return 0;
 674
 675 destroy_wiphy:
 676         virt_wifi_destroy_wiphy(common_wiphy);
 677 notifier:
 678         unregister_netdevice_notifier(&virt_wifi_notifier);
 679         return err;
 680 }
 681
 682 /* Acquires and releases the rtnl lock. */
 683 static void __exit virt_wifi_cleanup_module(void)
 684 {
 685         /* Will delete any devices that depend on the wiphy. */
 686         rtnl_link_unregister(&virt_wifi_link_ops);
 687         virt_wifi_destroy_wiphy(common_wiphy);
 688         unregister_netdevice_notifier(&virt_wifi_notifier);
 689 }
 690
 691 module_init(virt_wifi_init_module);
 692 module_exit(virt_wifi_cleanup_module);
 693
 694 MODULE_LICENSE("GPL v2");
 695 MODULE_AUTHOR("Cody Schuffelen <schuffelen@google.com>");
 696 MODULE_DESCRIPTION("Driver for a wireless wrapper of ethernet devices");
 697 MODULE_ALIAS_RTNL_LINK("virt_wifi");