1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2003-2008 Takahiro Hirofuchi
4 */
5
6 #include <linux/string.h>
7 #include <linux/module.h>
8 #include <linux/device.h>
9 #include <linux/scatterlist.h>
10
11 #include "usbip_common.h"
12 #include "stub.h"
13
14 #define DRIVER_AUTHOR "Takahiro Hirofuchi"
15 #define DRIVER_DESC "USB/IP Host Driver"
16
17 struct kmem_cache *stub_priv_cache;
18
19 /*
20 * busid_tables defines matching busids that usbip can grab. A user can change
21 * dynamically what device is locally used and what device is exported to a
22 * remote host.
23 */
24 #define MAX_BUSID 16
25 static struct bus_id_priv busid_table[MAX_BUSID];
26 static DEFINE_SPINLOCK(busid_table_lock);
27
init_busid_table(void)28 static void init_busid_table(void)
29 {
30 int i;
31
32 /*
33 * This also sets the bus_table[i].status to
34 * STUB_BUSID_OTHER, which is 0.
35 */
36 memset(busid_table, 0, sizeof(busid_table));
37
38 for (i = 0; i < MAX_BUSID; i++)
39 spin_lock_init(&busid_table[i].busid_lock);
40 }
41
42 /*
43 * Find the index of the busid by name.
44 * Must be called with busid_table_lock held.
45 */
get_busid_idx(const char * busid)46 static int get_busid_idx(const char *busid)
47 {
48 int i;
49 int idx = -1;
50
51 for (i = 0; i < MAX_BUSID; i++) {
52 spin_lock(&busid_table[i].busid_lock);
53 if (busid_table[i].name[0])
54 if (!strncmp(busid_table[i].name, busid, BUSID_SIZE)) {
55 idx = i;
56 spin_unlock(&busid_table[i].busid_lock);
57 break;
58 }
59 spin_unlock(&busid_table[i].busid_lock);
60 }
61 return idx;
62 }
63
64 /* Returns holding busid_lock. Should call put_busid_priv() to unlock */
get_busid_priv(const char * busid)65 struct bus_id_priv *get_busid_priv(const char *busid)
66 {
67 int idx;
68 struct bus_id_priv *bid = NULL;
69
70 spin_lock(&busid_table_lock);
71 idx = get_busid_idx(busid);
72 if (idx >= 0) {
73 bid = &(busid_table[idx]);
74 /* get busid_lock before returning */
75 spin_lock(&bid->busid_lock);
76 }
77 spin_unlock(&busid_table_lock);
78
79 return bid;
80 }
81
put_busid_priv(struct bus_id_priv * bid)82 void put_busid_priv(struct bus_id_priv *bid)
83 {
84 if (bid)
85 spin_unlock(&bid->busid_lock);
86 }
87
add_match_busid(char * busid)88 static int add_match_busid(char *busid)
89 {
90 int i;
91 int ret = -1;
92
93 spin_lock(&busid_table_lock);
94 /* already registered? */
95 if (get_busid_idx(busid) >= 0) {
96 ret = 0;
97 goto out;
98 }
99
100 for (i = 0; i < MAX_BUSID; i++) {
101 spin_lock(&busid_table[i].busid_lock);
102 if (!busid_table[i].name[0]) {
103 strscpy(busid_table[i].name, busid, BUSID_SIZE);
104 if ((busid_table[i].status != STUB_BUSID_ALLOC) &&
105 (busid_table[i].status != STUB_BUSID_REMOV))
106 busid_table[i].status = STUB_BUSID_ADDED;
107 ret = 0;
108 spin_unlock(&busid_table[i].busid_lock);
109 break;
110 }
111 spin_unlock(&busid_table[i].busid_lock);
112 }
113
114 out:
115 spin_unlock(&busid_table_lock);
116
117 return ret;
118 }
119
del_match_busid(char * busid)120 int del_match_busid(char *busid)
121 {
122 int idx;
123 int ret = -1;
124
125 spin_lock(&busid_table_lock);
126 idx = get_busid_idx(busid);
127 if (idx < 0)
128 goto out;
129
130 /* found */
131 ret = 0;
132
133 spin_lock(&busid_table[idx].busid_lock);
134
135 if (busid_table[idx].status == STUB_BUSID_OTHER)
136 memset(busid_table[idx].name, 0, BUSID_SIZE);
137
138 if ((busid_table[idx].status != STUB_BUSID_OTHER) &&
139 (busid_table[idx].status != STUB_BUSID_ADDED))
140 busid_table[idx].status = STUB_BUSID_REMOV;
141
142 spin_unlock(&busid_table[idx].busid_lock);
143 out:
144 spin_unlock(&busid_table_lock);
145
146 return ret;
147 }
148
match_busid_show(struct device_driver * drv,char * buf)149 static ssize_t match_busid_show(struct device_driver *drv, char *buf)
150 {
151 int i;
152 char *out = buf;
153
154 spin_lock(&busid_table_lock);
155 for (i = 0; i < MAX_BUSID; i++) {
156 spin_lock(&busid_table[i].busid_lock);
157 if (busid_table[i].name[0])
158 out += sprintf(out, "%s ", busid_table[i].name);
159 spin_unlock(&busid_table[i].busid_lock);
160 }
161 spin_unlock(&busid_table_lock);
162 out += sprintf(out, "\n");
163
164 return out - buf;
165 }
166
match_busid_store(struct device_driver * dev,const char * buf,size_t count)167 static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
168 size_t count)
169 {
170 char busid[BUSID_SIZE];
171
172 if (count < 5)
173 return -EINVAL;
174
175 /* busid needs to include \0 termination */
176 if (strscpy(busid, buf + 4, BUSID_SIZE) < 0)
177 return -EINVAL;
178
179 if (!strncmp(buf, "add ", 4)) {
180 if (add_match_busid(busid) < 0)
181 return -ENOMEM;
182
183 pr_debug("add busid %s\n", busid);
184 return count;
185 }
186
187 if (!strncmp(buf, "del ", 4)) {
188 if (del_match_busid(busid) < 0)
189 return -ENODEV;
190
191 pr_debug("del busid %s\n", busid);
192 return count;
193 }
194
195 return -EINVAL;
196 }
197 static DRIVER_ATTR_RW(match_busid);
198
do_rebind(char * busid,struct bus_id_priv * busid_priv)199 static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
200 {
201 int ret = 0;
202
203 /* device_attach() callers should hold parent lock for USB */
204 if (busid_priv->udev->dev.parent)
205 device_lock(busid_priv->udev->dev.parent);
206 ret = device_attach(&busid_priv->udev->dev);
207 if (busid_priv->udev->dev.parent)
208 device_unlock(busid_priv->udev->dev.parent);
209 if (ret < 0)
210 dev_err(&busid_priv->udev->dev, "rebind failed\n");
211 return ret;
212 }
213
stub_device_rebind(void)214 static void stub_device_rebind(void)
215 {
216 #if IS_MODULE(CONFIG_USBIP_HOST)
217 struct bus_id_priv *busid_priv;
218 int i;
219
220 /* update status to STUB_BUSID_OTHER so probe ignores the device */
221 spin_lock(&busid_table_lock);
222 for (i = 0; i < MAX_BUSID; i++) {
223 if (busid_table[i].name[0] &&
224 busid_table[i].shutdown_busid) {
225 busid_priv = &(busid_table[i]);
226 busid_priv->status = STUB_BUSID_OTHER;
227 }
228 }
229 spin_unlock(&busid_table_lock);
230
231 /* now run rebind - no need to hold locks. driver files are removed */
232 for (i = 0; i < MAX_BUSID; i++) {
233 if (busid_table[i].name[0] &&
234 busid_table[i].shutdown_busid) {
235 busid_priv = &(busid_table[i]);
236 do_rebind(busid_table[i].name, busid_priv);
237 }
238 }
239 #endif
240 }
241
rebind_store(struct device_driver * dev,const char * buf,size_t count)242 static ssize_t rebind_store(struct device_driver *dev, const char *buf,
243 size_t count)
244 {
245 int ret;
246 int len;
247 struct bus_id_priv *bid;
248
249 /* buf length should be less that BUSID_SIZE */
250 len = strnlen(buf, BUSID_SIZE);
251
252 if (!(len < BUSID_SIZE))
253 return -EINVAL;
254
255 bid = get_busid_priv(buf);
256 if (!bid)
257 return -ENODEV;
258
259 /* mark the device for deletion so probe ignores it during rescan */
260 bid->status = STUB_BUSID_OTHER;
261 /* release the busid lock */
262 put_busid_priv(bid);
263
264 ret = do_rebind((char *) buf, bid);
265 if (ret < 0)
266 return ret;
267
268 /* delete device from busid_table */
269 del_match_busid((char *) buf);
270
271 return count;
272 }
273
274 static DRIVER_ATTR_WO(rebind);
275
stub_priv_pop_from_listhead(struct list_head * listhead)276 static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
277 {
278 struct stub_priv *priv, *tmp;
279
280 list_for_each_entry_safe(priv, tmp, listhead, list) {
281 list_del_init(&priv->list);
282 return priv;
283 }
284
285 return NULL;
286 }
287
stub_free_priv_and_urb(struct stub_priv * priv)288 void stub_free_priv_and_urb(struct stub_priv *priv)
289 {
290 struct urb *urb;
291 int i;
292
293 for (i = 0; i < priv->num_urbs; i++) {
294 urb = priv->urbs[i];
295
296 if (!urb)
297 return;
298
299 kfree(urb->setup_packet);
300 urb->setup_packet = NULL;
301
302
303 if (urb->transfer_buffer && !priv->sgl) {
304 kfree(urb->transfer_buffer);
305 urb->transfer_buffer = NULL;
306 }
307
308 if (urb->num_sgs) {
309 sgl_free(urb->sg);
310 urb->sg = NULL;
311 urb->num_sgs = 0;
312 }
313
314 usb_free_urb(urb);
315 }
316 if (!list_empty(&priv->list))
317 list_del(&priv->list);
318 if (priv->sgl)
319 sgl_free(priv->sgl);
320 kfree(priv->urbs);
321 kmem_cache_free(stub_priv_cache, priv);
322 }
323
stub_priv_pop(struct stub_device * sdev)324 static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
325 {
326 unsigned long flags;
327 struct stub_priv *priv;
328
329 spin_lock_irqsave(&sdev->priv_lock, flags);
330
331 priv = stub_priv_pop_from_listhead(&sdev->priv_init);
332 if (priv)
333 goto done;
334
335 priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
336 if (priv)
337 goto done;
338
339 priv = stub_priv_pop_from_listhead(&sdev->priv_free);
340
341 done:
342 spin_unlock_irqrestore(&sdev->priv_lock, flags);
343
344 return priv;
345 }
346
stub_device_cleanup_urbs(struct stub_device * sdev)347 void stub_device_cleanup_urbs(struct stub_device *sdev)
348 {
349 struct stub_priv *priv;
350 int i;
351
352 dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");
353
354 while ((priv = stub_priv_pop(sdev))) {
355 for (i = 0; i < priv->num_urbs; i++)
356 usb_kill_urb(priv->urbs[i]);
357
358 stub_free_priv_and_urb(priv);
359 }
360 }
361
usbip_host_init(void)362 static int __init usbip_host_init(void)
363 {
364 int ret;
365
366 init_busid_table();
367
368 stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
369 if (!stub_priv_cache) {
370 pr_err("kmem_cache_create failed\n");
371 return -ENOMEM;
372 }
373
374 ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
375 if (ret) {
376 pr_err("usb_register failed %d\n", ret);
377 goto err_usb_register;
378 }
379
380 ret = driver_create_file(&stub_driver.drvwrap.driver,
381 &driver_attr_match_busid);
382 if (ret) {
383 pr_err("driver_create_file failed\n");
384 goto err_create_file;
385 }
386
387 ret = driver_create_file(&stub_driver.drvwrap.driver,
388 &driver_attr_rebind);
389 if (ret) {
390 pr_err("driver_create_file failed\n");
391 goto err_create_file;
392 }
393
394 return ret;
395
396 err_create_file:
397 usb_deregister_device_driver(&stub_driver);
398 err_usb_register:
399 kmem_cache_destroy(stub_priv_cache);
400 return ret;
401 }
402
usbip_host_exit(void)403 static void __exit usbip_host_exit(void)
404 {
405 driver_remove_file(&stub_driver.drvwrap.driver,
406 &driver_attr_match_busid);
407
408 driver_remove_file(&stub_driver.drvwrap.driver,
409 &driver_attr_rebind);
410
411 /*
412 * deregister() calls stub_disconnect() for all devices. Device
413 * specific data is cleared in stub_disconnect().
414 */
415 usb_deregister_device_driver(&stub_driver);
416
417 /* initiate scan to attach devices */
418 stub_device_rebind();
419
420 kmem_cache_destroy(stub_priv_cache);
421 }
422
423 module_init(usbip_host_init);
424 module_exit(usbip_host_exit);
425
426 MODULE_AUTHOR(DRIVER_AUTHOR);
427 MODULE_DESCRIPTION(DRIVER_DESC);
428 MODULE_LICENSE("GPL");
429