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 int len;
171 char busid[BUSID_SIZE];
172
173 if (count < 5)
174 return -EINVAL;
175
176 /* busid needs to include \0 termination */
177 len = strlcpy(busid, buf + 4, BUSID_SIZE);
178 if (sizeof(busid) <= len)
179 return -EINVAL;
180
181 if (!strncmp(buf, "add ", 4)) {
182 if (add_match_busid(busid) < 0)
183 return -ENOMEM;
184
185 pr_debug("add busid %s\n", busid);
186 return count;
187 }
188
189 if (!strncmp(buf, "del ", 4)) {
190 if (del_match_busid(busid) < 0)
191 return -ENODEV;
192
193 pr_debug("del busid %s\n", busid);
194 return count;
195 }
196
197 return -EINVAL;
198 }
199 static DRIVER_ATTR_RW(match_busid);
200
do_rebind(char * busid,struct bus_id_priv * busid_priv)201 static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
202 {
203 int ret = 0;
204
205 /* device_attach() callers should hold parent lock for USB */
206 if (busid_priv->udev->dev.parent)
207 device_lock(busid_priv->udev->dev.parent);
208 ret = device_attach(&busid_priv->udev->dev);
209 if (busid_priv->udev->dev.parent)
210 device_unlock(busid_priv->udev->dev.parent);
211 if (ret < 0)
212 dev_err(&busid_priv->udev->dev, "rebind failed\n");
213 return ret;
214 }
215
stub_device_rebind(void)216 static void stub_device_rebind(void)
217 {
218 #if IS_MODULE(CONFIG_USBIP_HOST)
219 struct bus_id_priv *busid_priv;
220 int i;
221
222 /* update status to STUB_BUSID_OTHER so probe ignores the device */
223 spin_lock(&busid_table_lock);
224 for (i = 0; i < MAX_BUSID; i++) {
225 if (busid_table[i].name[0] &&
226 busid_table[i].shutdown_busid) {
227 busid_priv = &(busid_table[i]);
228 busid_priv->status = STUB_BUSID_OTHER;
229 }
230 }
231 spin_unlock(&busid_table_lock);
232
233 /* now run rebind - no need to hold locks. driver files are removed */
234 for (i = 0; i < MAX_BUSID; i++) {
235 if (busid_table[i].name[0] &&
236 busid_table[i].shutdown_busid) {
237 busid_priv = &(busid_table[i]);
238 do_rebind(busid_table[i].name, busid_priv);
239 }
240 }
241 #endif
242 }
243
rebind_store(struct device_driver * dev,const char * buf,size_t count)244 static ssize_t rebind_store(struct device_driver *dev, const char *buf,
245 size_t count)
246 {
247 int ret;
248 int len;
249 struct bus_id_priv *bid;
250
251 /* buf length should be less that BUSID_SIZE */
252 len = strnlen(buf, BUSID_SIZE);
253
254 if (!(len < BUSID_SIZE))
255 return -EINVAL;
256
257 bid = get_busid_priv(buf);
258 if (!bid)
259 return -ENODEV;
260
261 /* mark the device for deletion so probe ignores it during rescan */
262 bid->status = STUB_BUSID_OTHER;
263 /* release the busid lock */
264 put_busid_priv(bid);
265
266 ret = do_rebind((char *) buf, bid);
267 if (ret < 0)
268 return ret;
269
270 /* delete device from busid_table */
271 del_match_busid((char *) buf);
272
273 return count;
274 }
275
276 static DRIVER_ATTR_WO(rebind);
277
stub_priv_pop_from_listhead(struct list_head * listhead)278 static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
279 {
280 struct stub_priv *priv, *tmp;
281
282 list_for_each_entry_safe(priv, tmp, listhead, list) {
283 list_del_init(&priv->list);
284 return priv;
285 }
286
287 return NULL;
288 }
289
stub_free_priv_and_urb(struct stub_priv * priv)290 void stub_free_priv_and_urb(struct stub_priv *priv)
291 {
292 struct urb *urb;
293 int i;
294
295 for (i = 0; i < priv->num_urbs; i++) {
296 urb = priv->urbs[i];
297
298 if (!urb)
299 return;
300
301 kfree(urb->setup_packet);
302 urb->setup_packet = NULL;
303
304
305 if (urb->transfer_buffer && !priv->sgl) {
306 kfree(urb->transfer_buffer);
307 urb->transfer_buffer = NULL;
308 }
309
310 if (urb->num_sgs) {
311 sgl_free(urb->sg);
312 urb->sg = NULL;
313 urb->num_sgs = 0;
314 }
315
316 usb_free_urb(urb);
317 }
318 if (!list_empty(&priv->list))
319 list_del(&priv->list);
320 if (priv->sgl)
321 sgl_free(priv->sgl);
322 kfree(priv->urbs);
323 kmem_cache_free(stub_priv_cache, priv);
324 }
325
stub_priv_pop(struct stub_device * sdev)326 static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
327 {
328 unsigned long flags;
329 struct stub_priv *priv;
330
331 spin_lock_irqsave(&sdev->priv_lock, flags);
332
333 priv = stub_priv_pop_from_listhead(&sdev->priv_init);
334 if (priv)
335 goto done;
336
337 priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
338 if (priv)
339 goto done;
340
341 priv = stub_priv_pop_from_listhead(&sdev->priv_free);
342
343 done:
344 spin_unlock_irqrestore(&sdev->priv_lock, flags);
345
346 return priv;
347 }
348
stub_device_cleanup_urbs(struct stub_device * sdev)349 void stub_device_cleanup_urbs(struct stub_device *sdev)
350 {
351 struct stub_priv *priv;
352 int i;
353
354 dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");
355
356 while ((priv = stub_priv_pop(sdev))) {
357 for (i = 0; i < priv->num_urbs; i++)
358 usb_kill_urb(priv->urbs[i]);
359
360 stub_free_priv_and_urb(priv);
361 }
362 }
363
usbip_host_init(void)364 static int __init usbip_host_init(void)
365 {
366 int ret;
367
368 init_busid_table();
369
370 stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
371 if (!stub_priv_cache) {
372 pr_err("kmem_cache_create failed\n");
373 return -ENOMEM;
374 }
375
376 ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
377 if (ret) {
378 pr_err("usb_register failed %d\n", ret);
379 goto err_usb_register;
380 }
381
382 ret = driver_create_file(&stub_driver.drvwrap.driver,
383 &driver_attr_match_busid);
384 if (ret) {
385 pr_err("driver_create_file failed\n");
386 goto err_create_file;
387 }
388
389 ret = driver_create_file(&stub_driver.drvwrap.driver,
390 &driver_attr_rebind);
391 if (ret) {
392 pr_err("driver_create_file failed\n");
393 goto err_create_file;
394 }
395
396 return ret;
397
398 err_create_file:
399 usb_deregister_device_driver(&stub_driver);
400 err_usb_register:
401 kmem_cache_destroy(stub_priv_cache);
402 return ret;
403 }
404
usbip_host_exit(void)405 static void __exit usbip_host_exit(void)
406 {
407 driver_remove_file(&stub_driver.drvwrap.driver,
408 &driver_attr_match_busid);
409
410 driver_remove_file(&stub_driver.drvwrap.driver,
411 &driver_attr_rebind);
412
413 /*
414 * deregister() calls stub_disconnect() for all devices. Device
415 * specific data is cleared in stub_disconnect().
416 */
417 usb_deregister_device_driver(&stub_driver);
418
419 /* initiate scan to attach devices */
420 stub_device_rebind();
421
422 kmem_cache_destroy(stub_priv_cache);
423 }
424
425 module_init(usbip_host_init);
426 module_exit(usbip_host_exit);
427
428 MODULE_AUTHOR(DRIVER_AUTHOR);
429 MODULE_DESCRIPTION(DRIVER_DESC);
430 MODULE_LICENSE("GPL");
431