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 #define VIRT_WIFI_SSID "VirtWifi"
140 #define VIRT_WIFI_SSID_LEN 8
141
virt_wifi_inform_bss(struct wiphy * wiphy)142 static void virt_wifi_inform_bss(struct wiphy *wiphy)
143 {
144 u64 tsf = div_u64(ktime_get_boottime_ns(), 1000);
145 struct cfg80211_bss *informed_bss;
146 static const struct {
147 u8 tag;
148 u8 len;
149 u8 ssid[8];
150 } __packed ssid = {
151 .tag = WLAN_EID_SSID,
152 .len = VIRT_WIFI_SSID_LEN,
153 .ssid = VIRT_WIFI_SSID,
154 };
155
156 informed_bss = cfg80211_inform_bss(wiphy, &channel_5ghz,
157 CFG80211_BSS_FTYPE_PRESP,
158 fake_router_bssid, tsf,
159 WLAN_CAPABILITY_ESS, 0,
160 (void *)&ssid, sizeof(ssid),
161 DBM_TO_MBM(-50), GFP_KERNEL);
162 cfg80211_put_bss(wiphy, informed_bss);
163 }
164
165 /* Called with the rtnl lock held. */
virt_wifi_scan(struct wiphy * wiphy,struct cfg80211_scan_request * request)166 static int virt_wifi_scan(struct wiphy *wiphy,
167 struct cfg80211_scan_request *request)
168 {
169 struct virt_wifi_wiphy_priv *priv = wiphy_priv(wiphy);
170
171 wiphy_debug(wiphy, "scan\n");
172
173 if (priv->scan_request || priv->being_deleted)
174 return -EBUSY;
175
176 priv->scan_request = request;
177 schedule_delayed_work(&priv->scan_result, HZ * 2);
178
179 return 0;
180 }
181
182 /* Acquires and releases the rdev BSS lock. */
virt_wifi_scan_result(struct work_struct * work)183 static void virt_wifi_scan_result(struct work_struct *work)
184 {
185 struct virt_wifi_wiphy_priv *priv =
186 container_of(work, struct virt_wifi_wiphy_priv,
187 scan_result.work);
188 struct wiphy *wiphy = priv_to_wiphy(priv);
189 struct cfg80211_scan_info scan_info = { .aborted = false };
190
191 virt_wifi_inform_bss(wiphy);
192
193 /* Schedules work which acquires and releases the rtnl lock. */
194 cfg80211_scan_done(priv->scan_request, &scan_info);
195 priv->scan_request = NULL;
196 }
197
198 /* May acquire and release the rdev BSS lock. */
virt_wifi_cancel_scan(struct wiphy * wiphy)199 static void virt_wifi_cancel_scan(struct wiphy *wiphy)
200 {
201 struct virt_wifi_wiphy_priv *priv = wiphy_priv(wiphy);
202
203 cancel_delayed_work_sync(&priv->scan_result);
204 /* Clean up dangling callbacks if necessary. */
205 if (priv->scan_request) {
206 struct cfg80211_scan_info scan_info = { .aborted = true };
207 /* Schedules work which acquires and releases the rtnl lock. */
208 cfg80211_scan_done(priv->scan_request, &scan_info);
209 priv->scan_request = NULL;
210 }
211 }
212
213 struct virt_wifi_netdev_priv {
214 struct delayed_work connect;
215 struct net_device *lowerdev;
216 struct net_device *upperdev;
217 u32 tx_packets;
218 u32 tx_failed;
219 u32 connect_requested_ssid_len;
220 u8 connect_requested_ssid[IEEE80211_MAX_SSID_LEN];
221 u8 connect_requested_bss[ETH_ALEN];
222 bool is_up;
223 bool is_connected;
224 bool being_deleted;
225 };
226
227 /* Called with the rtnl lock held. */
virt_wifi_connect(struct wiphy * wiphy,struct net_device * netdev,struct cfg80211_connect_params * sme)228 static int virt_wifi_connect(struct wiphy *wiphy, struct net_device *netdev,
229 struct cfg80211_connect_params *sme)
230 {
231 struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
232 bool could_schedule;
233
234 if (priv->being_deleted || !priv->is_up)
235 return -EBUSY;
236
237 if (!sme->ssid)
238 return -EINVAL;
239
240 priv->connect_requested_ssid_len = sme->ssid_len;
241 memcpy(priv->connect_requested_ssid, sme->ssid, sme->ssid_len);
242
243 could_schedule = schedule_delayed_work(&priv->connect, HZ * 2);
244 if (!could_schedule)
245 return -EBUSY;
246
247 if (sme->bssid) {
248 ether_addr_copy(priv->connect_requested_bss, sme->bssid);
249 } else {
250 virt_wifi_inform_bss(wiphy);
251 eth_zero_addr(priv->connect_requested_bss);
252 }
253
254 wiphy_debug(wiphy, "connect\n");
255
256 return 0;
257 }
258
259 /* Acquires and releases the rdev event lock. */
virt_wifi_connect_complete(struct work_struct * work)260 static void virt_wifi_connect_complete(struct work_struct *work)
261 {
262 struct virt_wifi_netdev_priv *priv =
263 container_of(work, struct virt_wifi_netdev_priv, connect.work);
264 u8 *requested_bss = priv->connect_requested_bss;
265 bool right_addr = ether_addr_equal(requested_bss, fake_router_bssid);
266 bool right_ssid = priv->connect_requested_ssid_len == VIRT_WIFI_SSID_LEN &&
267 !memcmp(priv->connect_requested_ssid, VIRT_WIFI_SSID,
268 priv->connect_requested_ssid_len);
269 u16 status = WLAN_STATUS_SUCCESS;
270
271 if (is_zero_ether_addr(requested_bss))
272 requested_bss = NULL;
273
274 if (!priv->is_up || (requested_bss && !right_addr) || !right_ssid)
275 status = WLAN_STATUS_UNSPECIFIED_FAILURE;
276 else
277 priv->is_connected = true;
278
279 /* Schedules an event that acquires the rtnl lock. */
280 cfg80211_connect_result(priv->upperdev, requested_bss, NULL, 0, NULL, 0,
281 status, GFP_KERNEL);
282 netif_carrier_on(priv->upperdev);
283 }
284
285 /* May acquire and release the rdev event lock. */
virt_wifi_cancel_connect(struct net_device * netdev)286 static void virt_wifi_cancel_connect(struct net_device *netdev)
287 {
288 struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
289
290 /* If there is work pending, clean up dangling callbacks. */
291 if (cancel_delayed_work_sync(&priv->connect)) {
292 /* Schedules an event that acquires the rtnl lock. */
293 cfg80211_connect_result(priv->upperdev,
294 priv->connect_requested_bss, NULL, 0,
295 NULL, 0,
296 WLAN_STATUS_UNSPECIFIED_FAILURE,
297 GFP_KERNEL);
298 }
299 }
300
301 /* Called with the rtnl lock held. Acquires the rdev event lock. */
virt_wifi_disconnect(struct wiphy * wiphy,struct net_device * netdev,u16 reason_code)302 static int virt_wifi_disconnect(struct wiphy *wiphy, struct net_device *netdev,
303 u16 reason_code)
304 {
305 struct virt_wifi_netdev_priv *priv = netdev_priv(netdev);
306
307 if (priv->being_deleted)
308 return -EBUSY;
309
310 wiphy_debug(wiphy, "disconnect\n");
311 virt_wifi_cancel_connect(netdev);
312
313 cfg80211_disconnected(netdev, reason_code, NULL, 0, true, GFP_KERNEL);
314 priv->is_connected = false;
315 netif_carrier_off(netdev);
316
317 return 0;
318 }
319
320 /* Called with the rtnl lock held. */
virt_wifi_get_station(struct wiphy * wiphy,struct net_device * dev,const u8 * mac,struct station_info * sinfo)321 static int virt_wifi_get_station(struct wiphy *wiphy, struct net_device *dev,
322 const u8 *mac, struct station_info *sinfo)
323 {
324 struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
325
326 wiphy_debug(wiphy, "get_station\n");
327
328 if (!priv->is_connected || !ether_addr_equal(mac, fake_router_bssid))
329 return -ENOENT;
330
331 sinfo->filled = BIT_ULL(NL80211_STA_INFO_TX_PACKETS) |
332 BIT_ULL(NL80211_STA_INFO_TX_FAILED) |
333 BIT_ULL(NL80211_STA_INFO_SIGNAL) |
334 BIT_ULL(NL80211_STA_INFO_TX_BITRATE);
335 sinfo->tx_packets = priv->tx_packets;
336 sinfo->tx_failed = priv->tx_failed;
337 /* For CFG80211_SIGNAL_TYPE_MBM, value is expressed in _dBm_ */
338 sinfo->signal = -50;
339 sinfo->txrate = (struct rate_info) {
340 .legacy = 10, /* units are 100kbit/s */
341 };
342 return 0;
343 }
344
345 /* Called with the rtnl lock held. */
virt_wifi_dump_station(struct wiphy * wiphy,struct net_device * dev,int idx,u8 * mac,struct station_info * sinfo)346 static int virt_wifi_dump_station(struct wiphy *wiphy, struct net_device *dev,
347 int idx, u8 *mac, struct station_info *sinfo)
348 {
349 struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
350
351 wiphy_debug(wiphy, "dump_station\n");
352
353 if (idx != 0 || !priv->is_connected)
354 return -ENOENT;
355
356 ether_addr_copy(mac, fake_router_bssid);
357 return virt_wifi_get_station(wiphy, dev, fake_router_bssid, sinfo);
358 }
359
360 static const struct cfg80211_ops virt_wifi_cfg80211_ops = {
361 .scan = virt_wifi_scan,
362
363 .connect = virt_wifi_connect,
364 .disconnect = virt_wifi_disconnect,
365
366 .get_station = virt_wifi_get_station,
367 .dump_station = virt_wifi_dump_station,
368 };
369
370 /* Acquires and releases the rtnl lock. */
virt_wifi_make_wiphy(void)371 static struct wiphy *virt_wifi_make_wiphy(void)
372 {
373 struct wiphy *wiphy;
374 struct virt_wifi_wiphy_priv *priv;
375 int err;
376
377 wiphy = wiphy_new(&virt_wifi_cfg80211_ops, sizeof(*priv));
378
379 if (!wiphy)
380 return NULL;
381
382 wiphy->max_scan_ssids = 4;
383 wiphy->max_scan_ie_len = 1000;
384 wiphy->signal_type = CFG80211_SIGNAL_TYPE_MBM;
385
386 wiphy->bands[NL80211_BAND_2GHZ] = &band_2ghz;
387 wiphy->bands[NL80211_BAND_5GHZ] = &band_5ghz;
388 wiphy->bands[NL80211_BAND_60GHZ] = NULL;
389
390 wiphy->interface_modes = BIT(NL80211_IFTYPE_STATION);
391
392 priv = wiphy_priv(wiphy);
393 priv->being_deleted = false;
394 priv->scan_request = NULL;
395 INIT_DELAYED_WORK(&priv->scan_result, virt_wifi_scan_result);
396
397 err = wiphy_register(wiphy);
398 if (err < 0) {
399 wiphy_free(wiphy);
400 return NULL;
401 }
402
403 return wiphy;
404 }
405
406 /* Acquires and releases the rtnl lock. */
virt_wifi_destroy_wiphy(struct wiphy * wiphy)407 static void virt_wifi_destroy_wiphy(struct wiphy *wiphy)
408 {
409 struct virt_wifi_wiphy_priv *priv;
410
411 WARN(!wiphy, "%s called with null wiphy", __func__);
412 if (!wiphy)
413 return;
414
415 priv = wiphy_priv(wiphy);
416 priv->being_deleted = true;
417 virt_wifi_cancel_scan(wiphy);
418
419 if (wiphy->registered)
420 wiphy_unregister(wiphy);
421 wiphy_free(wiphy);
422 }
423
424 /* Enters and exits a RCU-bh critical section. */
virt_wifi_start_xmit(struct sk_buff * skb,struct net_device * dev)425 static netdev_tx_t virt_wifi_start_xmit(struct sk_buff *skb,
426 struct net_device *dev)
427 {
428 struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
429
430 priv->tx_packets++;
431 if (!priv->is_connected) {
432 priv->tx_failed++;
433 return NET_XMIT_DROP;
434 }
435
436 skb->dev = priv->lowerdev;
437 return dev_queue_xmit(skb);
438 }
439
440 /* Called with rtnl lock held. */
virt_wifi_net_device_open(struct net_device * dev)441 static int virt_wifi_net_device_open(struct net_device *dev)
442 {
443 struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
444
445 priv->is_up = true;
446 return 0;
447 }
448
449 /* Called with rtnl lock held. */
virt_wifi_net_device_stop(struct net_device * dev)450 static int virt_wifi_net_device_stop(struct net_device *dev)
451 {
452 struct virt_wifi_netdev_priv *n_priv = netdev_priv(dev);
453
454 n_priv->is_up = false;
455
456 if (!dev->ieee80211_ptr)
457 return 0;
458
459 virt_wifi_cancel_scan(dev->ieee80211_ptr->wiphy);
460 virt_wifi_cancel_connect(dev);
461 netif_carrier_off(dev);
462
463 return 0;
464 }
465
virt_wifi_net_device_get_iflink(const struct net_device * dev)466 static int virt_wifi_net_device_get_iflink(const struct net_device *dev)
467 {
468 struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
469
470 return priv->lowerdev->ifindex;
471 }
472
473 static const struct net_device_ops virt_wifi_ops = {
474 .ndo_start_xmit = virt_wifi_start_xmit,
475 .ndo_open = virt_wifi_net_device_open,
476 .ndo_stop = virt_wifi_net_device_stop,
477 .ndo_get_iflink = virt_wifi_net_device_get_iflink,
478 };
479
480 /* Invoked as part of rtnl lock release. */
virt_wifi_net_device_destructor(struct net_device * dev)481 static void virt_wifi_net_device_destructor(struct net_device *dev)
482 {
483 /* Delayed past dellink to allow nl80211 to react to the device being
484 * deleted.
485 */
486 kfree(dev->ieee80211_ptr);
487 dev->ieee80211_ptr = NULL;
488 }
489
490 /* No lock interaction. */
virt_wifi_setup(struct net_device * dev)491 static void virt_wifi_setup(struct net_device *dev)
492 {
493 ether_setup(dev);
494 dev->netdev_ops = &virt_wifi_ops;
495 dev->needs_free_netdev = true;
496 }
497
498 /* Called in a RCU read critical section from netif_receive_skb */
virt_wifi_rx_handler(struct sk_buff ** pskb)499 static rx_handler_result_t virt_wifi_rx_handler(struct sk_buff **pskb)
500 {
501 struct sk_buff *skb = *pskb;
502 struct virt_wifi_netdev_priv *priv =
503 rcu_dereference(skb->dev->rx_handler_data);
504
505 if (!priv->is_connected)
506 return RX_HANDLER_PASS;
507
508 /* GFP_ATOMIC because this is a packet interrupt handler. */
509 skb = skb_share_check(skb, GFP_ATOMIC);
510 if (!skb) {
511 dev_err(&priv->upperdev->dev, "can't skb_share_check\n");
512 return RX_HANDLER_CONSUMED;
513 }
514
515 *pskb = skb;
516 skb->dev = priv->upperdev;
517 skb->pkt_type = PACKET_HOST;
518 return RX_HANDLER_ANOTHER;
519 }
520
521 /* Called with rtnl lock held. */
virt_wifi_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)522 static int virt_wifi_newlink(struct net *src_net, struct net_device *dev,
523 struct nlattr *tb[], struct nlattr *data[],
524 struct netlink_ext_ack *extack)
525 {
526 struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
527 int err;
528
529 if (!tb[IFLA_LINK])
530 return -EINVAL;
531
532 netif_carrier_off(dev);
533
534 priv->upperdev = dev;
535 priv->lowerdev = __dev_get_by_index(src_net,
536 nla_get_u32(tb[IFLA_LINK]));
537
538 if (!priv->lowerdev)
539 return -ENODEV;
540 if (!tb[IFLA_MTU])
541 dev->mtu = priv->lowerdev->mtu;
542 else if (dev->mtu > priv->lowerdev->mtu)
543 return -EINVAL;
544
545 err = netdev_rx_handler_register(priv->lowerdev, virt_wifi_rx_handler,
546 priv);
547 if (err) {
548 dev_err(&priv->lowerdev->dev,
549 "can't netdev_rx_handler_register: %d\n", err);
550 return err;
551 }
552
553 eth_hw_addr_inherit(dev, priv->lowerdev);
554 netif_stacked_transfer_operstate(priv->lowerdev, dev);
555
556 SET_NETDEV_DEV(dev, &priv->lowerdev->dev);
557 dev->ieee80211_ptr = kzalloc(sizeof(*dev->ieee80211_ptr), GFP_KERNEL);
558
559 if (!dev->ieee80211_ptr) {
560 err = -ENOMEM;
561 goto remove_handler;
562 }
563
564 dev->ieee80211_ptr->iftype = NL80211_IFTYPE_STATION;
565 dev->ieee80211_ptr->wiphy = common_wiphy;
566
567 err = register_netdevice(dev);
568 if (err) {
569 dev_err(&priv->lowerdev->dev, "can't register_netdevice: %d\n",
570 err);
571 goto free_wireless_dev;
572 }
573
574 err = netdev_upper_dev_link(priv->lowerdev, dev, extack);
575 if (err) {
576 dev_err(&priv->lowerdev->dev, "can't netdev_upper_dev_link: %d\n",
577 err);
578 goto unregister_netdev;
579 }
580
581 dev->priv_destructor = virt_wifi_net_device_destructor;
582 priv->being_deleted = false;
583 priv->is_connected = false;
584 priv->is_up = false;
585 INIT_DELAYED_WORK(&priv->connect, virt_wifi_connect_complete);
586 __module_get(THIS_MODULE);
587
588 return 0;
589 unregister_netdev:
590 unregister_netdevice(dev);
591 free_wireless_dev:
592 kfree(dev->ieee80211_ptr);
593 dev->ieee80211_ptr = NULL;
594 remove_handler:
595 netdev_rx_handler_unregister(priv->lowerdev);
596
597 return err;
598 }
599
600 /* Called with rtnl lock held. */
virt_wifi_dellink(struct net_device * dev,struct list_head * head)601 static void virt_wifi_dellink(struct net_device *dev,
602 struct list_head *head)
603 {
604 struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
605
606 if (dev->ieee80211_ptr)
607 virt_wifi_cancel_scan(dev->ieee80211_ptr->wiphy);
608
609 priv->being_deleted = true;
610 virt_wifi_cancel_connect(dev);
611 netif_carrier_off(dev);
612
613 netdev_rx_handler_unregister(priv->lowerdev);
614 netdev_upper_dev_unlink(priv->lowerdev, dev);
615
616 unregister_netdevice_queue(dev, head);
617 module_put(THIS_MODULE);
618
619 /* Deleting the wiphy is handled in the module destructor. */
620 }
621
622 static struct rtnl_link_ops virt_wifi_link_ops = {
623 .kind = "virt_wifi",
624 .setup = virt_wifi_setup,
625 .newlink = virt_wifi_newlink,
626 .dellink = virt_wifi_dellink,
627 .priv_size = sizeof(struct virt_wifi_netdev_priv),
628 };
629
netif_is_virt_wifi_dev(const struct net_device * dev)630 static bool netif_is_virt_wifi_dev(const struct net_device *dev)
631 {
632 return rcu_access_pointer(dev->rx_handler) == virt_wifi_rx_handler;
633 }
634
virt_wifi_event(struct notifier_block * this,unsigned long event,void * ptr)635 static int virt_wifi_event(struct notifier_block *this, unsigned long event,
636 void *ptr)
637 {
638 struct net_device *lower_dev = netdev_notifier_info_to_dev(ptr);
639 struct virt_wifi_netdev_priv *priv;
640 struct net_device *upper_dev;
641 LIST_HEAD(list_kill);
642
643 if (!netif_is_virt_wifi_dev(lower_dev))
644 return NOTIFY_DONE;
645
646 switch (event) {
647 case NETDEV_UNREGISTER:
648 priv = rtnl_dereference(lower_dev->rx_handler_data);
649 if (!priv)
650 return NOTIFY_DONE;
651
652 upper_dev = priv->upperdev;
653
654 upper_dev->rtnl_link_ops->dellink(upper_dev, &list_kill);
655 unregister_netdevice_many(&list_kill);
656 break;
657 }
658
659 return NOTIFY_DONE;
660 }
661
662 static struct notifier_block virt_wifi_notifier = {
663 .notifier_call = virt_wifi_event,
664 };
665
666 /* Acquires and releases the rtnl lock. */
virt_wifi_init_module(void)667 static int __init virt_wifi_init_module(void)
668 {
669 int err;
670
671 /* Guaranteed to be locally-administered and not multicast. */
672 eth_random_addr(fake_router_bssid);
673
674 err = register_netdevice_notifier(&virt_wifi_notifier);
675 if (err)
676 return err;
677
678 err = -ENOMEM;
679 common_wiphy = virt_wifi_make_wiphy();
680 if (!common_wiphy)
681 goto notifier;
682
683 err = rtnl_link_register(&virt_wifi_link_ops);
684 if (err)
685 goto destroy_wiphy;
686
687 return 0;
688
689 destroy_wiphy:
690 virt_wifi_destroy_wiphy(common_wiphy);
691 notifier:
692 unregister_netdevice_notifier(&virt_wifi_notifier);
693 return err;
694 }
695
696 /* Acquires and releases the rtnl lock. */
virt_wifi_cleanup_module(void)697 static void __exit virt_wifi_cleanup_module(void)
698 {
699 /* Will delete any devices that depend on the wiphy. */
700 rtnl_link_unregister(&virt_wifi_link_ops);
701 virt_wifi_destroy_wiphy(common_wiphy);
702 unregister_netdevice_notifier(&virt_wifi_notifier);
703 }
704
705 module_init(virt_wifi_init_module);
706 module_exit(virt_wifi_cleanup_module);
707
708 MODULE_LICENSE("GPL v2");
709 MODULE_AUTHOR("Cody Schuffelen <schuffelen@google.com>");
710 MODULE_DESCRIPTION("Driver for a wireless wrapper of ethernet devices");
711 MODULE_ALIAS_RTNL_LINK("virt_wifi");
712