xref: /linux/drivers/bluetooth/hci_vhci.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *
4  *  Bluetooth virtual HCI driver
5  *
6  *  Copyright (C) 2000-2001  Qualcomm Incorporated
7  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
8  *  Copyright (C) 2004-2006  Marcel Holtmann <marcel@holtmann.org>
9  */
10 
11 #include <linux/module.h>
12 #include <linux/unaligned.h>
13 
14 #include <linux/atomic.h>
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/types.h>
19 #include <linux/errno.h>
20 #include <linux/sched.h>
21 #include <linux/poll.h>
22 
23 #include <linux/skbuff.h>
24 #include <linux/miscdevice.h>
25 #include <linux/debugfs.h>
26 
27 #include <net/bluetooth/bluetooth.h>
28 #include <net/bluetooth/hci_core.h>
29 
30 #define VERSION "1.5"
31 
32 static bool amp;
33 
34 struct vhci_data {
35 	struct hci_dev *hdev;
36 
37 	wait_queue_head_t read_wait;
38 	struct sk_buff_head readq;
39 
40 	struct mutex open_mutex;
41 	struct delayed_work open_timeout;
42 	struct work_struct suspend_work;
43 
44 	bool suspended;
45 	bool wakeup;
46 	__u16 msft_opcode;
47 	bool aosp_capable;
48 	atomic_t initialized;
49 };
50 
51 static int vhci_open_dev(struct hci_dev *hdev)
52 {
53 	return 0;
54 }
55 
56 static int vhci_close_dev(struct hci_dev *hdev)
57 {
58 	struct vhci_data *data = hci_get_drvdata(hdev);
59 
60 	skb_queue_purge(&data->readq);
61 
62 	return 0;
63 }
64 
65 static int vhci_flush(struct hci_dev *hdev)
66 {
67 	struct vhci_data *data = hci_get_drvdata(hdev);
68 
69 	skb_queue_purge(&data->readq);
70 
71 	return 0;
72 }
73 
74 static int vhci_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
75 {
76 	struct vhci_data *data = hci_get_drvdata(hdev);
77 
78 	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
79 
80 	skb_queue_tail(&data->readq, skb);
81 
82 	if (atomic_read(&data->initialized))
83 		wake_up_interruptible(&data->read_wait);
84 	return 0;
85 }
86 
87 static int vhci_get_data_path_id(struct hci_dev *hdev, u8 *data_path_id)
88 {
89 	*data_path_id = 0;
90 	return 0;
91 }
92 
93 static int vhci_get_codec_config_data(struct hci_dev *hdev, __u8 type,
94 				      struct bt_codec *codec, __u8 *vnd_len,
95 				      __u8 **vnd_data)
96 {
97 	if (type != ESCO_LINK)
98 		return -EINVAL;
99 
100 	*vnd_len = 0;
101 	*vnd_data = NULL;
102 	return 0;
103 }
104 
105 static bool vhci_wakeup(struct hci_dev *hdev)
106 {
107 	struct vhci_data *data = hci_get_drvdata(hdev);
108 
109 	return data->wakeup;
110 }
111 
112 static ssize_t force_suspend_read(struct file *file, char __user *user_buf,
113 				  size_t count, loff_t *ppos)
114 {
115 	struct vhci_data *data = file->private_data;
116 	char buf[3];
117 
118 	buf[0] = data->suspended ? 'Y' : 'N';
119 	buf[1] = '\n';
120 	buf[2] = '\0';
121 	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
122 }
123 
124 static void vhci_suspend_work(struct work_struct *work)
125 {
126 	struct vhci_data *data = container_of(work, struct vhci_data,
127 					      suspend_work);
128 
129 	if (data->suspended)
130 		hci_suspend_dev(data->hdev);
131 	else
132 		hci_resume_dev(data->hdev);
133 }
134 
135 static ssize_t force_suspend_write(struct file *file,
136 				   const char __user *user_buf,
137 				   size_t count, loff_t *ppos)
138 {
139 	struct vhci_data *data = file->private_data;
140 	bool enable;
141 	int err;
142 
143 	err = kstrtobool_from_user(user_buf, count, &enable);
144 	if (err)
145 		return err;
146 
147 	if (data->suspended == enable)
148 		return -EALREADY;
149 
150 	data->suspended = enable;
151 
152 	schedule_work(&data->suspend_work);
153 
154 	return count;
155 }
156 
157 static const struct file_operations force_suspend_fops = {
158 	.open		= simple_open,
159 	.read		= force_suspend_read,
160 	.write		= force_suspend_write,
161 	.llseek		= default_llseek,
162 };
163 
164 static ssize_t force_wakeup_read(struct file *file, char __user *user_buf,
165 				 size_t count, loff_t *ppos)
166 {
167 	struct vhci_data *data = file->private_data;
168 	char buf[3];
169 
170 	buf[0] = data->wakeup ? 'Y' : 'N';
171 	buf[1] = '\n';
172 	buf[2] = '\0';
173 	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
174 }
175 
176 static ssize_t force_wakeup_write(struct file *file,
177 				  const char __user *user_buf, size_t count,
178 				  loff_t *ppos)
179 {
180 	struct vhci_data *data = file->private_data;
181 	bool enable;
182 	int err;
183 
184 	err = kstrtobool_from_user(user_buf, count, &enable);
185 	if (err)
186 		return err;
187 
188 	if (data->wakeup == enable)
189 		return -EALREADY;
190 
191 	data->wakeup = enable;
192 
193 	return count;
194 }
195 
196 static const struct file_operations force_wakeup_fops = {
197 	.open		= simple_open,
198 	.read		= force_wakeup_read,
199 	.write		= force_wakeup_write,
200 	.llseek		= default_llseek,
201 };
202 
203 static int msft_opcode_set(void *data, u64 val)
204 {
205 	struct vhci_data *vhci = data;
206 
207 	if (val > 0xffff || hci_opcode_ogf(val) != 0x3f)
208 		return -EINVAL;
209 
210 	if (vhci->msft_opcode)
211 		return -EALREADY;
212 
213 	vhci->msft_opcode = val;
214 
215 	return 0;
216 }
217 
218 static int msft_opcode_get(void *data, u64 *val)
219 {
220 	struct vhci_data *vhci = data;
221 
222 	*val = vhci->msft_opcode;
223 
224 	return 0;
225 }
226 
227 DEFINE_DEBUGFS_ATTRIBUTE(msft_opcode_fops, msft_opcode_get, msft_opcode_set,
228 			 "%llu\n");
229 
230 static ssize_t aosp_capable_read(struct file *file, char __user *user_buf,
231 				 size_t count, loff_t *ppos)
232 {
233 	struct vhci_data *vhci = file->private_data;
234 	char buf[3];
235 
236 	buf[0] = vhci->aosp_capable ? 'Y' : 'N';
237 	buf[1] = '\n';
238 	buf[2] = '\0';
239 	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
240 }
241 
242 static ssize_t aosp_capable_write(struct file *file,
243 				  const char __user *user_buf, size_t count,
244 				  loff_t *ppos)
245 {
246 	struct vhci_data *vhci = file->private_data;
247 	bool enable;
248 	int err;
249 
250 	err = kstrtobool_from_user(user_buf, count, &enable);
251 	if (err)
252 		return err;
253 
254 	if (!enable)
255 		return -EINVAL;
256 
257 	if (vhci->aosp_capable)
258 		return -EALREADY;
259 
260 	vhci->aosp_capable = enable;
261 
262 	return count;
263 }
264 
265 static const struct file_operations aosp_capable_fops = {
266 	.open		= simple_open,
267 	.read		= aosp_capable_read,
268 	.write		= aosp_capable_write,
269 	.llseek		= default_llseek,
270 };
271 
272 static int vhci_setup(struct hci_dev *hdev)
273 {
274 	struct vhci_data *vhci = hci_get_drvdata(hdev);
275 
276 	if (vhci->msft_opcode)
277 		hci_set_msft_opcode(hdev, vhci->msft_opcode);
278 
279 	if (vhci->aosp_capable)
280 		hci_set_aosp_capable(hdev);
281 
282 	return 0;
283 }
284 
285 static void vhci_coredump(struct hci_dev *hdev)
286 {
287 	/* No need to do anything */
288 }
289 
290 static void vhci_coredump_hdr(struct hci_dev *hdev, struct sk_buff *skb)
291 {
292 	char buf[80];
293 
294 	snprintf(buf, sizeof(buf), "Controller Name: vhci_ctrl\n");
295 	skb_put_data(skb, buf, strlen(buf));
296 
297 	snprintf(buf, sizeof(buf), "Firmware Version: vhci_fw\n");
298 	skb_put_data(skb, buf, strlen(buf));
299 
300 	snprintf(buf, sizeof(buf), "Driver: vhci_drv\n");
301 	skb_put_data(skb, buf, strlen(buf));
302 
303 	snprintf(buf, sizeof(buf), "Vendor: vhci\n");
304 	skb_put_data(skb, buf, strlen(buf));
305 }
306 
307 #define MAX_COREDUMP_LINE_LEN	40
308 
309 struct devcoredump_test_data {
310 	enum devcoredump_state state;
311 	unsigned int timeout;
312 	char data[MAX_COREDUMP_LINE_LEN];
313 };
314 
315 static inline void force_devcd_timeout(struct hci_dev *hdev,
316 				       unsigned int timeout)
317 {
318 #ifdef CONFIG_DEV_COREDUMP
319 	hdev->dump.timeout = msecs_to_jiffies(timeout * 1000);
320 #endif
321 }
322 
323 static ssize_t force_devcd_write(struct file *file, const char __user *user_buf,
324 				 size_t count, loff_t *ppos)
325 {
326 	struct vhci_data *data = file->private_data;
327 	struct hci_dev *hdev = data->hdev;
328 	struct sk_buff *skb = NULL;
329 	struct devcoredump_test_data dump_data;
330 	size_t data_size;
331 	int ret;
332 
333 	if (count < offsetof(struct devcoredump_test_data, data) ||
334 	    count > sizeof(dump_data))
335 		return -EINVAL;
336 
337 	if (copy_from_user(&dump_data, user_buf, count))
338 		return -EFAULT;
339 
340 	data_size = count - offsetof(struct devcoredump_test_data, data);
341 	skb = alloc_skb(data_size, GFP_ATOMIC);
342 	if (!skb)
343 		return -ENOMEM;
344 	skb_put_data(skb, &dump_data.data, data_size);
345 
346 	hci_devcd_register(hdev, vhci_coredump, vhci_coredump_hdr, NULL);
347 
348 	/* Force the devcoredump timeout */
349 	if (dump_data.timeout)
350 		force_devcd_timeout(hdev, dump_data.timeout);
351 
352 	ret = hci_devcd_init(hdev, skb->len);
353 	if (ret) {
354 		BT_ERR("Failed to generate devcoredump");
355 		kfree_skb(skb);
356 		return ret;
357 	}
358 
359 	hci_devcd_append(hdev, skb);
360 
361 	switch (dump_data.state) {
362 	case HCI_DEVCOREDUMP_DONE:
363 		hci_devcd_complete(hdev);
364 		break;
365 	case HCI_DEVCOREDUMP_ABORT:
366 		hci_devcd_abort(hdev);
367 		break;
368 	case HCI_DEVCOREDUMP_TIMEOUT:
369 		/* Do nothing */
370 		break;
371 	default:
372 		return -EINVAL;
373 	}
374 
375 	return count;
376 }
377 
378 static const struct file_operations force_devcoredump_fops = {
379 	.open		= simple_open,
380 	.write		= force_devcd_write,
381 };
382 
383 static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
384 {
385 	struct hci_dev *hdev;
386 	struct sk_buff *skb;
387 
388 	if (data->hdev)
389 		return -EBADFD;
390 
391 	/* bits 2-5 are reserved (must be zero) */
392 	if (opcode & 0x3c)
393 		return -EINVAL;
394 
395 	skb = bt_skb_alloc(4, GFP_KERNEL);
396 	if (!skb)
397 		return -ENOMEM;
398 
399 	hdev = hci_alloc_dev();
400 	if (!hdev) {
401 		kfree_skb(skb);
402 		return -ENOMEM;
403 	}
404 
405 	data->hdev = hdev;
406 
407 	hdev->bus = HCI_VIRTUAL;
408 	hci_set_drvdata(hdev, data);
409 
410 	hdev->open  = vhci_open_dev;
411 	hdev->close = vhci_close_dev;
412 	hdev->flush = vhci_flush;
413 	hdev->send  = vhci_send_frame;
414 	hdev->get_data_path_id = vhci_get_data_path_id;
415 	hdev->get_codec_config_data = vhci_get_codec_config_data;
416 	hdev->wakeup = vhci_wakeup;
417 	hdev->setup = vhci_setup;
418 	set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
419 
420 	/* bit 6 is for external configuration */
421 	if (opcode & 0x40)
422 		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
423 
424 	/* bit 7 is for raw device */
425 	if (opcode & 0x80)
426 		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
427 
428 	if (hci_register_dev(hdev) < 0) {
429 		BT_ERR("Can't register HCI device");
430 		hci_free_dev(hdev);
431 		data->hdev = NULL;
432 		kfree_skb(skb);
433 		return -EBUSY;
434 	}
435 
436 	debugfs_create_file("force_suspend", 0644, hdev->debugfs, data,
437 			    &force_suspend_fops);
438 
439 	debugfs_create_file("force_wakeup", 0644, hdev->debugfs, data,
440 			    &force_wakeup_fops);
441 
442 	if (IS_ENABLED(CONFIG_BT_MSFTEXT))
443 		debugfs_create_file("msft_opcode", 0644, hdev->debugfs, data,
444 				    &msft_opcode_fops);
445 
446 	if (IS_ENABLED(CONFIG_BT_AOSPEXT))
447 		debugfs_create_file("aosp_capable", 0644, hdev->debugfs, data,
448 				    &aosp_capable_fops);
449 
450 	debugfs_create_file("force_devcoredump", 0644, hdev->debugfs, data,
451 			    &force_devcoredump_fops);
452 
453 	hci_skb_pkt_type(skb) = HCI_VENDOR_PKT;
454 
455 	skb_put_u8(skb, 0xff);
456 	skb_put_u8(skb, opcode);
457 	put_unaligned_le16(hdev->id, skb_put(skb, 2));
458 	skb_queue_head(&data->readq, skb);
459 	atomic_inc(&data->initialized);
460 
461 	wake_up_interruptible(&data->read_wait);
462 	return 0;
463 }
464 
465 static int vhci_create_device(struct vhci_data *data, __u8 opcode)
466 {
467 	int err;
468 
469 	mutex_lock(&data->open_mutex);
470 	err = __vhci_create_device(data, opcode);
471 	mutex_unlock(&data->open_mutex);
472 
473 	return err;
474 }
475 
476 static inline ssize_t vhci_get_user(struct vhci_data *data,
477 				    struct iov_iter *from)
478 {
479 	size_t len = iov_iter_count(from);
480 	struct sk_buff *skb;
481 	__u8 pkt_type, opcode;
482 	int ret;
483 
484 	if (len < 2 || len > HCI_MAX_FRAME_SIZE)
485 		return -EINVAL;
486 
487 	skb = bt_skb_alloc(len, GFP_KERNEL);
488 	if (!skb)
489 		return -ENOMEM;
490 
491 	if (!copy_from_iter_full(skb_put(skb, len), len, from)) {
492 		kfree_skb(skb);
493 		return -EFAULT;
494 	}
495 
496 	pkt_type = *((__u8 *) skb->data);
497 	skb_pull(skb, 1);
498 
499 	switch (pkt_type) {
500 	case HCI_EVENT_PKT:
501 	case HCI_ACLDATA_PKT:
502 	case HCI_SCODATA_PKT:
503 	case HCI_ISODATA_PKT:
504 		if (!data->hdev) {
505 			kfree_skb(skb);
506 			return -ENODEV;
507 		}
508 
509 		hci_skb_pkt_type(skb) = pkt_type;
510 
511 		ret = hci_recv_frame(data->hdev, skb);
512 		break;
513 
514 	case HCI_VENDOR_PKT:
515 		cancel_delayed_work_sync(&data->open_timeout);
516 
517 		opcode = *((__u8 *) skb->data);
518 		skb_pull(skb, 1);
519 
520 		if (skb->len > 0) {
521 			kfree_skb(skb);
522 			return -EINVAL;
523 		}
524 
525 		kfree_skb(skb);
526 
527 		ret = vhci_create_device(data, opcode);
528 		break;
529 
530 	default:
531 		kfree_skb(skb);
532 		return -EINVAL;
533 	}
534 
535 	return (ret < 0) ? ret : len;
536 }
537 
538 static inline ssize_t vhci_put_user(struct vhci_data *data,
539 				    struct sk_buff *skb,
540 				    char __user *buf, int count)
541 {
542 	char __user *ptr = buf;
543 	int len;
544 
545 	len = min_t(unsigned int, skb->len, count);
546 
547 	if (copy_to_user(ptr, skb->data, len))
548 		return -EFAULT;
549 
550 	if (!data->hdev)
551 		return len;
552 
553 	data->hdev->stat.byte_tx += len;
554 
555 	switch (hci_skb_pkt_type(skb)) {
556 	case HCI_COMMAND_PKT:
557 		data->hdev->stat.cmd_tx++;
558 		break;
559 	case HCI_ACLDATA_PKT:
560 		data->hdev->stat.acl_tx++;
561 		break;
562 	case HCI_SCODATA_PKT:
563 		data->hdev->stat.sco_tx++;
564 		break;
565 	}
566 
567 	return len;
568 }
569 
570 static ssize_t vhci_read(struct file *file,
571 			 char __user *buf, size_t count, loff_t *pos)
572 {
573 	struct vhci_data *data = file->private_data;
574 	struct sk_buff *skb;
575 	ssize_t ret = 0;
576 
577 	while (count) {
578 		skb = skb_dequeue(&data->readq);
579 		if (skb) {
580 			ret = vhci_put_user(data, skb, buf, count);
581 			if (ret < 0)
582 				skb_queue_head(&data->readq, skb);
583 			else
584 				kfree_skb(skb);
585 			break;
586 		}
587 
588 		if (file->f_flags & O_NONBLOCK) {
589 			ret = -EAGAIN;
590 			break;
591 		}
592 
593 		ret = wait_event_interruptible(data->read_wait,
594 					       !skb_queue_empty(&data->readq));
595 		if (ret < 0)
596 			break;
597 	}
598 
599 	return ret;
600 }
601 
602 static ssize_t vhci_write(struct kiocb *iocb, struct iov_iter *from)
603 {
604 	struct file *file = iocb->ki_filp;
605 	struct vhci_data *data = file->private_data;
606 
607 	return vhci_get_user(data, from);
608 }
609 
610 static __poll_t vhci_poll(struct file *file, poll_table *wait)
611 {
612 	struct vhci_data *data = file->private_data;
613 
614 	poll_wait(file, &data->read_wait, wait);
615 
616 	if (!skb_queue_empty(&data->readq))
617 		return EPOLLIN | EPOLLRDNORM;
618 
619 	return EPOLLOUT | EPOLLWRNORM;
620 }
621 
622 static void vhci_open_timeout(struct work_struct *work)
623 {
624 	struct vhci_data *data = container_of(work, struct vhci_data,
625 					      open_timeout.work);
626 
627 	vhci_create_device(data, 0x00);
628 }
629 
630 static int vhci_open(struct inode *inode, struct file *file)
631 {
632 	struct vhci_data *data;
633 
634 	data = kzalloc(sizeof(*data), GFP_KERNEL);
635 	if (!data)
636 		return -ENOMEM;
637 
638 	skb_queue_head_init(&data->readq);
639 	init_waitqueue_head(&data->read_wait);
640 
641 	mutex_init(&data->open_mutex);
642 	INIT_DELAYED_WORK(&data->open_timeout, vhci_open_timeout);
643 	INIT_WORK(&data->suspend_work, vhci_suspend_work);
644 
645 	file->private_data = data;
646 	nonseekable_open(inode, file);
647 
648 	schedule_delayed_work(&data->open_timeout, msecs_to_jiffies(1000));
649 
650 	return 0;
651 }
652 
653 static int vhci_release(struct inode *inode, struct file *file)
654 {
655 	struct vhci_data *data = file->private_data;
656 	struct hci_dev *hdev;
657 
658 	cancel_delayed_work_sync(&data->open_timeout);
659 	flush_work(&data->suspend_work);
660 
661 	hdev = data->hdev;
662 
663 	if (hdev) {
664 		hci_unregister_dev(hdev);
665 		hci_free_dev(hdev);
666 	}
667 
668 	skb_queue_purge(&data->readq);
669 	file->private_data = NULL;
670 	kfree(data);
671 
672 	return 0;
673 }
674 
675 static const struct file_operations vhci_fops = {
676 	.owner		= THIS_MODULE,
677 	.read		= vhci_read,
678 	.write_iter	= vhci_write,
679 	.poll		= vhci_poll,
680 	.open		= vhci_open,
681 	.release	= vhci_release,
682 };
683 
684 static struct miscdevice vhci_miscdev = {
685 	.name	= "vhci",
686 	.fops	= &vhci_fops,
687 	.minor	= VHCI_MINOR,
688 };
689 module_misc_device(vhci_miscdev);
690 
691 module_param(amp, bool, 0644);
692 MODULE_PARM_DESC(amp, "Create AMP controller device");
693 
694 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
695 MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
696 MODULE_VERSION(VERSION);
697 MODULE_LICENSE("GPL");
698 MODULE_ALIAS("devname:vhci");
699 MODULE_ALIAS_MISCDEV(VHCI_MINOR);
700