1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2003-2008 Takahiro Hirofuchi
4 */
5
6 #include <linux/device.h>
7 #include <linux/file.h>
8 #include <linux/kthread.h>
9 #include <linux/module.h>
10
11 #include "usbip_common.h"
12 #include "stub.h"
13
14 /*
15 * usbip_status shows the status of usbip-host as long as this driver is bound
16 * to the target device.
17 */
usbip_status_show(struct device * dev,struct device_attribute * attr,char * buf)18 static ssize_t usbip_status_show(struct device *dev,
19 struct device_attribute *attr, char *buf)
20 {
21 struct stub_device *sdev = dev_get_drvdata(dev);
22 int status;
23
24 if (!sdev) {
25 dev_err(dev, "sdev is null\n");
26 return -ENODEV;
27 }
28
29 spin_lock_irq(&sdev->ud.lock);
30 status = sdev->ud.status;
31 spin_unlock_irq(&sdev->ud.lock);
32
33 return sysfs_emit(buf, "%d\n", status);
34 }
35 static DEVICE_ATTR_RO(usbip_status);
36
37 /*
38 * usbip_sockfd gets a socket descriptor of an established TCP connection that
39 * is used to transfer usbip requests by kernel threads. -1 is a magic number
40 * by which usbip connection is finished.
41 */
usbip_sockfd_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)42 static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *attr,
43 const char *buf, size_t count)
44 {
45 struct stub_device *sdev = dev_get_drvdata(dev);
46 int sockfd = 0;
47 struct socket *socket;
48 int rv;
49 struct task_struct *tcp_rx = NULL;
50 struct task_struct *tcp_tx = NULL;
51
52 if (!sdev) {
53 dev_err(dev, "sdev is null\n");
54 return -ENODEV;
55 }
56
57 rv = sscanf(buf, "%d", &sockfd);
58 if (rv != 1)
59 return -EINVAL;
60
61 if (sockfd != -1) {
62 int err;
63
64 dev_info(dev, "stub up\n");
65
66 mutex_lock(&sdev->ud.sysfs_lock);
67 spin_lock_irq(&sdev->ud.lock);
68
69 if (sdev->ud.status != SDEV_ST_AVAILABLE) {
70 dev_err(dev, "not ready\n");
71 goto err;
72 }
73
74 socket = sockfd_lookup(sockfd, &err);
75 if (!socket) {
76 dev_err(dev, "failed to lookup sock");
77 goto err;
78 }
79
80 if (socket->type != SOCK_STREAM) {
81 dev_err(dev, "Expecting SOCK_STREAM - found %d",
82 socket->type);
83 goto sock_err;
84 }
85
86 /* unlock and create threads and get tasks */
87 spin_unlock_irq(&sdev->ud.lock);
88 tcp_rx = kthread_create(stub_rx_loop, &sdev->ud, "stub_rx");
89 if (IS_ERR(tcp_rx)) {
90 sockfd_put(socket);
91 goto unlock_mutex;
92 }
93 tcp_tx = kthread_create(stub_tx_loop, &sdev->ud, "stub_tx");
94 if (IS_ERR(tcp_tx)) {
95 kthread_stop(tcp_rx);
96 sockfd_put(socket);
97 goto unlock_mutex;
98 }
99
100 /* get task structs now */
101 get_task_struct(tcp_rx);
102 get_task_struct(tcp_tx);
103
104 /* lock and update sdev->ud state */
105 spin_lock_irq(&sdev->ud.lock);
106 sdev->ud.tcp_socket = socket;
107 sdev->ud.sockfd = sockfd;
108 sdev->ud.tcp_rx = tcp_rx;
109 sdev->ud.tcp_tx = tcp_tx;
110 sdev->ud.status = SDEV_ST_USED;
111 spin_unlock_irq(&sdev->ud.lock);
112
113 wake_up_process(sdev->ud.tcp_rx);
114 wake_up_process(sdev->ud.tcp_tx);
115
116 mutex_unlock(&sdev->ud.sysfs_lock);
117
118 } else {
119 dev_info(dev, "stub down\n");
120
121 mutex_lock(&sdev->ud.sysfs_lock);
122
123 spin_lock_irq(&sdev->ud.lock);
124 if (sdev->ud.status != SDEV_ST_USED)
125 goto err;
126
127 spin_unlock_irq(&sdev->ud.lock);
128
129 usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
130 mutex_unlock(&sdev->ud.sysfs_lock);
131 }
132
133 return count;
134
135 sock_err:
136 sockfd_put(socket);
137 err:
138 spin_unlock_irq(&sdev->ud.lock);
139 unlock_mutex:
140 mutex_unlock(&sdev->ud.sysfs_lock);
141 return -EINVAL;
142 }
143 static DEVICE_ATTR_WO(usbip_sockfd);
144
145 static struct attribute *usbip_attrs[] = {
146 &dev_attr_usbip_status.attr,
147 &dev_attr_usbip_sockfd.attr,
148 &dev_attr_usbip_debug.attr,
149 NULL,
150 };
151 ATTRIBUTE_GROUPS(usbip);
152
stub_shutdown_connection(struct usbip_device * ud)153 static void stub_shutdown_connection(struct usbip_device *ud)
154 {
155 struct stub_device *sdev = container_of(ud, struct stub_device, ud);
156
157 /*
158 * When removing an exported device, kernel panic sometimes occurred
159 * and then EIP was sk_wait_data of stub_rx thread. Is this because
160 * sk_wait_data returned though stub_rx thread was already finished by
161 * step 1?
162 */
163 if (ud->tcp_socket) {
164 dev_dbg(&sdev->udev->dev, "shutdown sockfd %d\n", ud->sockfd);
165 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
166 }
167
168 /* 1. stop threads */
169 if (ud->tcp_rx) {
170 kthread_stop_put(ud->tcp_rx);
171 ud->tcp_rx = NULL;
172 }
173 if (ud->tcp_tx) {
174 kthread_stop_put(ud->tcp_tx);
175 ud->tcp_tx = NULL;
176 }
177
178 /*
179 * 2. close the socket
180 *
181 * tcp_socket is freed after threads are killed so that usbip_xmit does
182 * not touch NULL socket.
183 */
184 if (ud->tcp_socket) {
185 sockfd_put(ud->tcp_socket);
186 ud->tcp_socket = NULL;
187 ud->sockfd = -1;
188 }
189
190 /* 3. free used data */
191 stub_device_cleanup_urbs(sdev);
192
193 /* 4. free stub_unlink */
194 {
195 unsigned long flags;
196 struct stub_unlink *unlink, *tmp;
197
198 spin_lock_irqsave(&sdev->priv_lock, flags);
199 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
200 list_del(&unlink->list);
201 kfree(unlink);
202 }
203 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
204 list) {
205 list_del(&unlink->list);
206 kfree(unlink);
207 }
208 spin_unlock_irqrestore(&sdev->priv_lock, flags);
209 }
210 }
211
stub_device_reset(struct usbip_device * ud)212 static void stub_device_reset(struct usbip_device *ud)
213 {
214 struct stub_device *sdev = container_of(ud, struct stub_device, ud);
215 struct usb_device *udev = sdev->udev;
216 int ret;
217
218 dev_dbg(&udev->dev, "device reset");
219
220 ret = usb_lock_device_for_reset(udev, NULL);
221 if (ret < 0) {
222 dev_err(&udev->dev, "lock for reset\n");
223 spin_lock_irq(&ud->lock);
224 ud->status = SDEV_ST_ERROR;
225 spin_unlock_irq(&ud->lock);
226 return;
227 }
228
229 /* try to reset the device */
230 ret = usb_reset_device(udev);
231 usb_unlock_device(udev);
232
233 spin_lock_irq(&ud->lock);
234 if (ret) {
235 dev_err(&udev->dev, "device reset\n");
236 ud->status = SDEV_ST_ERROR;
237 } else {
238 dev_info(&udev->dev, "device reset\n");
239 ud->status = SDEV_ST_AVAILABLE;
240 }
241 spin_unlock_irq(&ud->lock);
242 }
243
stub_device_unusable(struct usbip_device * ud)244 static void stub_device_unusable(struct usbip_device *ud)
245 {
246 spin_lock_irq(&ud->lock);
247 ud->status = SDEV_ST_ERROR;
248 spin_unlock_irq(&ud->lock);
249 }
250
251 /**
252 * stub_device_alloc - allocate a new stub_device struct
253 * @udev: usb_device of a new device
254 *
255 * Allocates and initializes a new stub_device struct.
256 */
stub_device_alloc(struct usb_device * udev)257 static struct stub_device *stub_device_alloc(struct usb_device *udev)
258 {
259 struct stub_device *sdev;
260 int busnum = udev->bus->busnum;
261 int devnum = udev->devnum;
262
263 dev_dbg(&udev->dev, "allocating stub device");
264
265 /* yes, it's a new device */
266 sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
267 if (!sdev)
268 return NULL;
269
270 sdev->udev = usb_get_dev(udev);
271
272 /*
273 * devid is defined with devnum when this driver is first allocated.
274 * devnum may change later if a device is reset. However, devid never
275 * changes during a usbip connection.
276 */
277 sdev->devid = (busnum << 16) | devnum;
278 sdev->ud.side = USBIP_STUB;
279 sdev->ud.status = SDEV_ST_AVAILABLE;
280 spin_lock_init(&sdev->ud.lock);
281 mutex_init(&sdev->ud.sysfs_lock);
282 sdev->ud.tcp_socket = NULL;
283 sdev->ud.sockfd = -1;
284
285 INIT_LIST_HEAD(&sdev->priv_init);
286 INIT_LIST_HEAD(&sdev->priv_tx);
287 INIT_LIST_HEAD(&sdev->priv_free);
288 INIT_LIST_HEAD(&sdev->unlink_free);
289 INIT_LIST_HEAD(&sdev->unlink_tx);
290 spin_lock_init(&sdev->priv_lock);
291
292 init_waitqueue_head(&sdev->tx_waitq);
293
294 sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
295 sdev->ud.eh_ops.reset = stub_device_reset;
296 sdev->ud.eh_ops.unusable = stub_device_unusable;
297
298 usbip_start_eh(&sdev->ud);
299
300 dev_dbg(&udev->dev, "register new device\n");
301
302 return sdev;
303 }
304
stub_device_free(struct stub_device * sdev)305 static void stub_device_free(struct stub_device *sdev)
306 {
307 kfree(sdev);
308 }
309
stub_probe(struct usb_device * udev)310 static int stub_probe(struct usb_device *udev)
311 {
312 struct stub_device *sdev = NULL;
313 const char *udev_busid = dev_name(&udev->dev);
314 struct bus_id_priv *busid_priv;
315 int rc = 0;
316 char save_status;
317
318 dev_dbg(&udev->dev, "Enter probe\n");
319
320 /* Not sure if this is our device. Allocate here to avoid
321 * calling alloc while holding busid_table lock.
322 */
323 sdev = stub_device_alloc(udev);
324 if (!sdev)
325 return -ENOMEM;
326
327 /* check we should claim or not by busid_table */
328 busid_priv = get_busid_priv(udev_busid);
329 if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
330 (busid_priv->status == STUB_BUSID_OTHER)) {
331 dev_info(&udev->dev,
332 "%s is not in match_busid table... skip!\n",
333 udev_busid);
334
335 /*
336 * Return value should be ENODEV or ENOXIO to continue trying
337 * other matched drivers by the driver core.
338 * See driver_probe_device() in driver/base/dd.c
339 */
340 rc = -ENODEV;
341 if (!busid_priv)
342 goto sdev_free;
343
344 goto call_put_busid_priv;
345 }
346
347 if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
348 dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
349 udev_busid);
350 rc = -ENODEV;
351 goto call_put_busid_priv;
352 }
353
354 if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
355 dev_dbg(&udev->dev,
356 "%s is attached on vhci_hcd... skip!\n",
357 udev_busid);
358
359 rc = -ENODEV;
360 goto call_put_busid_priv;
361 }
362
363
364 dev_info(&udev->dev,
365 "usbip-host: register new device (bus %u dev %u)\n",
366 udev->bus->busnum, udev->devnum);
367
368 busid_priv->shutdown_busid = 0;
369
370 /* set private data to usb_device */
371 dev_set_drvdata(&udev->dev, sdev);
372
373 busid_priv->sdev = sdev;
374 busid_priv->udev = udev;
375
376 save_status = busid_priv->status;
377 busid_priv->status = STUB_BUSID_ALLOC;
378
379 /* release the busid_lock */
380 put_busid_priv(busid_priv);
381
382 /*
383 * Claim this hub port.
384 * It doesn't matter what value we pass as owner
385 * (struct dev_state) as long as it is unique.
386 */
387 rc = usb_hub_claim_port(udev->parent, udev->portnum,
388 (struct usb_dev_state *) udev);
389 if (rc) {
390 dev_dbg(&udev->dev, "unable to claim port\n");
391 goto err_port;
392 }
393
394 return 0;
395
396 err_port:
397 dev_set_drvdata(&udev->dev, NULL);
398
399 /* we already have busid_priv, just lock busid_lock */
400 spin_lock(&busid_priv->busid_lock);
401 busid_priv->sdev = NULL;
402 busid_priv->status = save_status;
403 spin_unlock(&busid_priv->busid_lock);
404 /* lock is released - go to free */
405 goto sdev_free;
406
407 call_put_busid_priv:
408 /* release the busid_lock */
409 put_busid_priv(busid_priv);
410
411 sdev_free:
412 usb_put_dev(udev);
413 stub_device_free(sdev);
414
415 return rc;
416 }
417
shutdown_busid(struct bus_id_priv * busid_priv)418 static void shutdown_busid(struct bus_id_priv *busid_priv)
419 {
420 usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
421
422 /* wait for the stop of the event handler */
423 usbip_stop_eh(&busid_priv->sdev->ud);
424 }
425
426 /*
427 * called in usb_disconnect() or usb_deregister()
428 * but only if actconfig(active configuration) exists
429 */
stub_disconnect(struct usb_device * udev)430 static void stub_disconnect(struct usb_device *udev)
431 {
432 struct stub_device *sdev;
433 const char *udev_busid = dev_name(&udev->dev);
434 struct bus_id_priv *busid_priv;
435 int rc;
436
437 dev_dbg(&udev->dev, "Enter disconnect\n");
438
439 busid_priv = get_busid_priv(udev_busid);
440 if (!busid_priv) {
441 BUG();
442 return;
443 }
444
445 sdev = dev_get_drvdata(&udev->dev);
446
447 /* get stub_device */
448 if (!sdev) {
449 dev_err(&udev->dev, "could not get device");
450 /* release busid_lock */
451 put_busid_priv(busid_priv);
452 return;
453 }
454
455 dev_set_drvdata(&udev->dev, NULL);
456
457 /* release busid_lock before call to remove device files */
458 put_busid_priv(busid_priv);
459
460 /*
461 * NOTE: rx/tx threads are invoked for each usb_device.
462 */
463
464 /* release port */
465 rc = usb_hub_release_port(udev->parent, udev->portnum,
466 (struct usb_dev_state *) udev);
467 /*
468 * NOTE: If a HUB disconnect triggered disconnect of the down stream
469 * device usb_hub_release_port will return -ENODEV so we can safely ignore
470 * that error here.
471 */
472 if (rc && (rc != -ENODEV)) {
473 dev_dbg(&udev->dev, "unable to release port (%i)\n", rc);
474 return;
475 }
476
477 /* If usb reset is called from event handler */
478 if (usbip_in_eh(current))
479 return;
480
481 /* we already have busid_priv, just lock busid_lock */
482 spin_lock(&busid_priv->busid_lock);
483 if (!busid_priv->shutdown_busid)
484 busid_priv->shutdown_busid = 1;
485 /* release busid_lock */
486 spin_unlock(&busid_priv->busid_lock);
487
488 /* shutdown the current connection */
489 shutdown_busid(busid_priv);
490
491 usb_put_dev(sdev->udev);
492
493 /* we already have busid_priv, just lock busid_lock */
494 spin_lock(&busid_priv->busid_lock);
495 /* free sdev */
496 busid_priv->sdev = NULL;
497 stub_device_free(sdev);
498
499 if (busid_priv->status == STUB_BUSID_ALLOC)
500 busid_priv->status = STUB_BUSID_ADDED;
501 /* release busid_lock */
502 spin_unlock(&busid_priv->busid_lock);
503 return;
504 }
505
506 #ifdef CONFIG_PM
507
508 /* These functions need usb_port_suspend and usb_port_resume,
509 * which reside in drivers/usb/core/usb.h. Skip for now. */
510
stub_suspend(struct usb_device * udev,pm_message_t message)511 static int stub_suspend(struct usb_device *udev, pm_message_t message)
512 {
513 dev_dbg(&udev->dev, "stub_suspend\n");
514
515 return 0;
516 }
517
stub_resume(struct usb_device * udev,pm_message_t message)518 static int stub_resume(struct usb_device *udev, pm_message_t message)
519 {
520 dev_dbg(&udev->dev, "stub_resume\n");
521
522 return 0;
523 }
524
525 #endif /* CONFIG_PM */
526
527 struct usb_device_driver stub_driver = {
528 .name = "usbip-host",
529 .probe = stub_probe,
530 .disconnect = stub_disconnect,
531 #ifdef CONFIG_PM
532 .suspend = stub_suspend,
533 .resume = stub_resume,
534 #endif
535 .supports_autosuspend = 0,
536 .dev_groups = usbip_groups,
537 };
538