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
 17struct 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
 25static struct bus_id_priv busid_table[MAX_BUSID];
 26static spinlock_t busid_table_lock;
 27
 28static 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	spin_lock_init(&busid_table_lock);
 39
 40	for (i = 0; i < MAX_BUSID; i++)
 41		spin_lock_init(&busid_table[i].busid_lock);
 42}
 43
 44/*
 45 * Find the index of the busid by name.
 46 * Must be called with busid_table_lock held.
 47 */
 48static int get_busid_idx(const char *busid)
 49{
 50	int i;
 51	int idx = -1;
 52
 53	for (i = 0; i < MAX_BUSID; i++) {
 54		spin_lock(&busid_table[i].busid_lock);
 55		if (busid_table[i].name[0])
 56			if (!strncmp(busid_table[i].name, busid, BUSID_SIZE)) {
 57				idx = i;
 58				spin_unlock(&busid_table[i].busid_lock);
 59				break;
 60			}
 61		spin_unlock(&busid_table[i].busid_lock);
 62	}
 63	return idx;
 64}
 65
 66/* Returns holding busid_lock. Should call put_busid_priv() to unlock */
 67struct bus_id_priv *get_busid_priv(const char *busid)
 68{
 69	int idx;
 70	struct bus_id_priv *bid = NULL;
 71
 72	spin_lock(&busid_table_lock);
 73	idx = get_busid_idx(busid);
 74	if (idx >= 0) {
 75		bid = &(busid_table[idx]);
 76		/* get busid_lock before returning */
 77		spin_lock(&bid->busid_lock);
 78	}
 79	spin_unlock(&busid_table_lock);
 80
 81	return bid;
 82}
 83
 84void put_busid_priv(struct bus_id_priv *bid)
 85{
 86	if (bid)
 87		spin_unlock(&bid->busid_lock);
 88}
 89
 90static int add_match_busid(char *busid)
 91{
 92	int i;
 93	int ret = -1;
 94
 95	spin_lock(&busid_table_lock);
 96	/* already registered? */
 97	if (get_busid_idx(busid) >= 0) {
 98		ret = 0;
 99		goto out;
100	}
101
102	for (i = 0; i < MAX_BUSID; i++) {
103		spin_lock(&busid_table[i].busid_lock);
104		if (!busid_table[i].name[0]) {
105			strlcpy(busid_table[i].name, busid, BUSID_SIZE);
106			if ((busid_table[i].status != STUB_BUSID_ALLOC) &&
107			    (busid_table[i].status != STUB_BUSID_REMOV))
108				busid_table[i].status = STUB_BUSID_ADDED;
109			ret = 0;
110			spin_unlock(&busid_table[i].busid_lock);
111			break;
112		}
113		spin_unlock(&busid_table[i].busid_lock);
114	}
115
116out:
117	spin_unlock(&busid_table_lock);
118
119	return ret;
120}
121
122int del_match_busid(char *busid)
123{
124	int idx;
125	int ret = -1;
126
127	spin_lock(&busid_table_lock);
128	idx = get_busid_idx(busid);
129	if (idx < 0)
130		goto out;
131
132	/* found */
133	ret = 0;
134
135	spin_lock(&busid_table[idx].busid_lock);
136
137	if (busid_table[idx].status == STUB_BUSID_OTHER)
138		memset(busid_table[idx].name, 0, BUSID_SIZE);
139
140	if ((busid_table[idx].status != STUB_BUSID_OTHER) &&
141	    (busid_table[idx].status != STUB_BUSID_ADDED))
142		busid_table[idx].status = STUB_BUSID_REMOV;
143
144	spin_unlock(&busid_table[idx].busid_lock);
145out:
146	spin_unlock(&busid_table_lock);
147
148	return ret;
149}
150
151static ssize_t match_busid_show(struct device_driver *drv, char *buf)
152{
153	int i;
154	char *out = buf;
155
156	spin_lock(&busid_table_lock);
157	for (i = 0; i < MAX_BUSID; i++) {
158		spin_lock(&busid_table[i].busid_lock);
159		if (busid_table[i].name[0])
160			out += sprintf(out, "%s ", busid_table[i].name);
161		spin_unlock(&busid_table[i].busid_lock);
162	}
163	spin_unlock(&busid_table_lock);
164	out += sprintf(out, "\n");
165
166	return out - buf;
167}
168
169static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
170				 size_t count)
171{
172	int len;
173	char busid[BUSID_SIZE];
174
175	if (count < 5)
176		return -EINVAL;
177
178	/* busid needs to include \0 termination */
179	len = strlcpy(busid, buf + 4, BUSID_SIZE);
180	if (sizeof(busid) <= len)
181		return -EINVAL;
182
183	if (!strncmp(buf, "add ", 4)) {
184		if (add_match_busid(busid) < 0)
185			return -ENOMEM;
186
187		pr_debug("add busid %s\n", busid);
188		return count;
189	}
190
191	if (!strncmp(buf, "del ", 4)) {
192		if (del_match_busid(busid) < 0)
193			return -ENODEV;
194
195		pr_debug("del busid %s\n", busid);
196		return count;
197	}
198
199	return -EINVAL;
200}
201static DRIVER_ATTR_RW(match_busid);
202
203static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
204{
205	int ret = 0;
206
207	/* device_attach() callers should hold parent lock for USB */
208	if (busid_priv->udev->dev.parent)
209		device_lock(busid_priv->udev->dev.parent);
210	ret = device_attach(&busid_priv->udev->dev);
211	if (busid_priv->udev->dev.parent)
212		device_unlock(busid_priv->udev->dev.parent);
213	if (ret < 0)
214		dev_err(&busid_priv->udev->dev, "rebind failed\n");
215	return ret;
216}
217
218static void stub_device_rebind(void)
219{
220#if IS_MODULE(CONFIG_USBIP_HOST)
221	struct bus_id_priv *busid_priv;
222	int i;
223
224	/* update status to STUB_BUSID_OTHER so probe ignores the device */
225	spin_lock(&busid_table_lock);
226	for (i = 0; i < MAX_BUSID; i++) {
227		if (busid_table[i].name[0] &&
228		    busid_table[i].shutdown_busid) {
229			busid_priv = &(busid_table[i]);
230			busid_priv->status = STUB_BUSID_OTHER;
231		}
232	}
233	spin_unlock(&busid_table_lock);
234
235	/* now run rebind - no need to hold locks. driver files are removed */
236	for (i = 0; i < MAX_BUSID; i++) {
237		if (busid_table[i].name[0] &&
238		    busid_table[i].shutdown_busid) {
239			busid_priv = &(busid_table[i]);
240			do_rebind(busid_table[i].name, busid_priv);
241		}
242	}
243#endif
244}
245
246static ssize_t rebind_store(struct device_driver *dev, const char *buf,
247				 size_t count)
248{
249	int ret;
250	int len;
251	struct bus_id_priv *bid;
252
253	/* buf length should be less that BUSID_SIZE */
254	len = strnlen(buf, BUSID_SIZE);
255
256	if (!(len < BUSID_SIZE))
257		return -EINVAL;
258
259	bid = get_busid_priv(buf);
260	if (!bid)
261		return -ENODEV;
262
263	/* mark the device for deletion so probe ignores it during rescan */
264	bid->status = STUB_BUSID_OTHER;
265	/* release the busid lock */
266	put_busid_priv(bid);
267
268	ret = do_rebind((char *) buf, bid);
269	if (ret < 0)
270		return ret;
271
272	/* delete device from busid_table */
273	del_match_busid((char *) buf);
274
275	return count;
276}
277
278static DRIVER_ATTR_WO(rebind);
279
280static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
281{
282	struct stub_priv *priv, *tmp;
283
284	list_for_each_entry_safe(priv, tmp, listhead, list) {
285		list_del_init(&priv->list);
286		return priv;
287	}
288
289	return NULL;
290}
291
292void stub_free_priv_and_urb(struct stub_priv *priv)
293{
294	struct urb *urb;
295	int i;
296
297	for (i = 0; i < priv->num_urbs; i++) {
298		urb = priv->urbs[i];
299
300		if (!urb)
301			return;
302
303		kfree(urb->setup_packet);
304		urb->setup_packet = NULL;
305
306
307		if (urb->transfer_buffer && !priv->sgl) {
308			kfree(urb->transfer_buffer);
309			urb->transfer_buffer = NULL;
310		}
311
312		if (urb->num_sgs) {
313			sgl_free(urb->sg);
314			urb->sg = NULL;
315			urb->num_sgs = 0;
316		}
317
318		usb_free_urb(urb);
319	}
320	if (!list_empty(&priv->list))
321		list_del(&priv->list);
322	if (priv->sgl)
323		sgl_free(priv->sgl);
324	kfree(priv->urbs);
325	kmem_cache_free(stub_priv_cache, priv);
326}
327
328static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
329{
330	unsigned long flags;
331	struct stub_priv *priv;
332
333	spin_lock_irqsave(&sdev->priv_lock, flags);
334
335	priv = stub_priv_pop_from_listhead(&sdev->priv_init);
336	if (priv)
337		goto done;
338
339	priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
340	if (priv)
341		goto done;
342
343	priv = stub_priv_pop_from_listhead(&sdev->priv_free);
344
345done:
346	spin_unlock_irqrestore(&sdev->priv_lock, flags);
347
348	return priv;
349}
350
351void stub_device_cleanup_urbs(struct stub_device *sdev)
352{
353	struct stub_priv *priv;
354	int i;
355
356	dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");
357
358	while ((priv = stub_priv_pop(sdev))) {
359		for (i = 0; i < priv->num_urbs; i++)
360			usb_kill_urb(priv->urbs[i]);
361
362		stub_free_priv_and_urb(priv);
363	}
364}
365
366static int __init usbip_host_init(void)
367{
368	int ret;
369
370	init_busid_table();
371
372	stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
373	if (!stub_priv_cache) {
374		pr_err("kmem_cache_create failed\n");
375		return -ENOMEM;
376	}
377
378	ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
379	if (ret) {
380		pr_err("usb_register failed %d\n", ret);
381		goto err_usb_register;
382	}
383
384	ret = driver_create_file(&stub_driver.drvwrap.driver,
385				 &driver_attr_match_busid);
386	if (ret) {
387		pr_err("driver_create_file failed\n");
388		goto err_create_file;
389	}
390
391	ret = driver_create_file(&stub_driver.drvwrap.driver,
392				 &driver_attr_rebind);
393	if (ret) {
394		pr_err("driver_create_file failed\n");
395		goto err_create_file;
396	}
397
398	return ret;
399
400err_create_file:
401	usb_deregister_device_driver(&stub_driver);
402err_usb_register:
403	kmem_cache_destroy(stub_priv_cache);
404	return ret;
405}
406
407static void __exit usbip_host_exit(void)
408{
409	driver_remove_file(&stub_driver.drvwrap.driver,
410			   &driver_attr_match_busid);
411
412	driver_remove_file(&stub_driver.drvwrap.driver,
413			   &driver_attr_rebind);
414
415	/*
416	 * deregister() calls stub_disconnect() for all devices. Device
417	 * specific data is cleared in stub_disconnect().
418	 */
419	usb_deregister_device_driver(&stub_driver);
420
421	/* initiate scan to attach devices */
422	stub_device_rebind();
423
424	kmem_cache_destroy(stub_priv_cache);
425}
426
427module_init(usbip_host_init);
428module_exit(usbip_host_exit);
429
430MODULE_AUTHOR(DRIVER_AUTHOR);
431MODULE_DESCRIPTION(DRIVER_DESC);
432MODULE_LICENSE("GPL");