xref: /linux/drivers/bluetooth/hci_vhci.c (revision 2f804aca48322f02a8f44cca540663845ee80fb1) 
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 <asm/unaligned.h>
13 
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/slab.h>
17 #include <linux/types.h>
18 #include <linux/errno.h>
19 #include <linux/sched.h>
20 #include <linux/poll.h>
21 
22 #include <linux/skbuff.h>
23 #include <linux/miscdevice.h>
24 #include <linux/debugfs.h>
25 
26 #include <net/bluetooth/bluetooth.h>
27 #include <net/bluetooth/hci_core.h>
28 
29 #define VERSION "1.5"
30 
31 static bool amp;
32 
33 struct vhci_data {
34 	struct hci_dev *hdev;
35 
36 	wait_queue_head_t read_wait;
37 	struct sk_buff_head readq;
38 
39 	struct mutex open_mutex;
40 	struct delayed_work open_timeout;
41 	struct work_struct suspend_work;
42 
43 	bool suspended;
44 	bool wakeup;
45 	__u16 msft_opcode;
46 	bool aosp_capable;
47 };
48 
49 static int vhci_open_dev(struct hci_dev *hdev)
50 {
51 	return 0;
52 }
53 
54 static int vhci_close_dev(struct hci_dev *hdev)
55 {
56 	struct vhci_data *data = hci_get_drvdata(hdev);
57 
58 	skb_queue_purge(&data->readq);
59 
60 	return 0;
61 }
62 
63 static int vhci_flush(struct hci_dev *hdev)
64 {
65 	struct vhci_data *data = hci_get_drvdata(hdev);
66 
67 	skb_queue_purge(&data->readq);
68 
69 	return 0;
70 }
71 
72 static int vhci_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
73 {
74 	struct vhci_data *data = hci_get_drvdata(hdev);
75 
76 	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
77 	skb_queue_tail(&data->readq, skb);
78 
79 	wake_up_interruptible(&data->read_wait);
80 	return 0;
81 }
82 
83 static int vhci_get_data_path_id(struct hci_dev *hdev, u8 *data_path_id)
84 {
85 	*data_path_id = 0;
86 	return 0;
87 }
88 
89 static int vhci_get_codec_config_data(struct hci_dev *hdev, __u8 type,
90 				      struct bt_codec *codec, __u8 *vnd_len,
91 				      __u8 **vnd_data)
92 {
93 	if (type != ESCO_LINK)
94 		return -EINVAL;
95 
96 	*vnd_len = 0;
97 	*vnd_data = NULL;
98 	return 0;
99 }
100 
101 static bool vhci_wakeup(struct hci_dev *hdev)
102 {
103 	struct vhci_data *data = hci_get_drvdata(hdev);
104 
105 	return data->wakeup;
106 }
107 
108 static ssize_t force_suspend_read(struct file *file, char __user *user_buf,
109 				  size_t count, loff_t *ppos)
110 {
111 	struct vhci_data *data = file->private_data;
112 	char buf[3];
113 
114 	buf[0] = data->suspended ? 'Y' : 'N';
115 	buf[1] = '\n';
116 	buf[2] = '\0';
117 	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
118 }
119 
120 static void vhci_suspend_work(struct work_struct *work)
121 {
122 	struct vhci_data *data = container_of(work, struct vhci_data,
123 					      suspend_work);
124 
125 	if (data->suspended)
126 		hci_suspend_dev(data->hdev);
127 	else
128 		hci_resume_dev(data->hdev);
129 }
130 
131 static ssize_t force_suspend_write(struct file *file,
132 				   const char __user *user_buf,
133 				   size_t count, loff_t *ppos)
134 {
135 	struct vhci_data *data = file->private_data;
136 	bool enable;
137 	int err;
138 
139 	err = kstrtobool_from_user(user_buf, count, &enable);
140 	if (err)
141 		return err;
142 
143 	if (data->suspended == enable)
144 		return -EALREADY;
145 
146 	data->suspended = enable;
147 
148 	schedule_work(&data->suspend_work);
149 
150 	return count;
151 }
152 
153 static const struct file_operations force_suspend_fops = {
154 	.open		= simple_open,
155 	.read		= force_suspend_read,
156 	.write		= force_suspend_write,
157 	.llseek		= default_llseek,
158 };
159 
160 static ssize_t force_wakeup_read(struct file *file, char __user *user_buf,
161 				 size_t count, loff_t *ppos)
162 {
163 	struct vhci_data *data = file->private_data;
164 	char buf[3];
165 
166 	buf[0] = data->wakeup ? 'Y' : 'N';
167 	buf[1] = '\n';
168 	buf[2] = '\0';
169 	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
170 }
171 
172 static ssize_t force_wakeup_write(struct file *file,
173 				  const char __user *user_buf, size_t count,
174 				  loff_t *ppos)
175 {
176 	struct vhci_data *data = file->private_data;
177 	bool enable;
178 	int err;
179 
180 	err = kstrtobool_from_user(user_buf, count, &enable);
181 	if (err)
182 		return err;
183 
184 	if (data->wakeup == enable)
185 		return -EALREADY;
186 
187 	data->wakeup = enable;
188 
189 	return count;
190 }
191 
192 static const struct file_operations force_wakeup_fops = {
193 	.open		= simple_open,
194 	.read		= force_wakeup_read,
195 	.write		= force_wakeup_write,
196 	.llseek		= default_llseek,
197 };
198 
199 static int msft_opcode_set(void *data, u64 val)
200 {
201 	struct vhci_data *vhci = data;
202 
203 	if (val > 0xffff || hci_opcode_ogf(val) != 0x3f)
204 		return -EINVAL;
205 
206 	if (vhci->msft_opcode)
207 		return -EALREADY;
208 
209 	vhci->msft_opcode = val;
210 
211 	return 0;
212 }
213 
214 static int msft_opcode_get(void *data, u64 *val)
215 {
216 	struct vhci_data *vhci = data;
217 
218 	*val = vhci->msft_opcode;
219 
220 	return 0;
221 }
222 
223 DEFINE_DEBUGFS_ATTRIBUTE(msft_opcode_fops, msft_opcode_get, msft_opcode_set,
224 			 "%llu\n");
225 
226 static ssize_t aosp_capable_read(struct file *file, char __user *user_buf,
227 				 size_t count, loff_t *ppos)
228 {
229 	struct vhci_data *vhci = file->private_data;
230 	char buf[3];
231 
232 	buf[0] = vhci->aosp_capable ? 'Y' : 'N';
233 	buf[1] = '\n';
234 	buf[2] = '\0';
235 	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
236 }
237 
238 static ssize_t aosp_capable_write(struct file *file,
239 				  const char __user *user_buf, size_t count,
240 				  loff_t *ppos)
241 {
242 	struct vhci_data *vhci = file->private_data;
243 	bool enable;
244 	int err;
245 
246 	err = kstrtobool_from_user(user_buf, count, &enable);
247 	if (err)
248 		return err;
249 
250 	if (!enable)
251 		return -EINVAL;
252 
253 	if (vhci->aosp_capable)
254 		return -EALREADY;
255 
256 	vhci->aosp_capable = enable;
257 
258 	return count;
259 }
260 
261 static const struct file_operations aosp_capable_fops = {
262 	.open		= simple_open,
263 	.read		= aosp_capable_read,
264 	.write		= aosp_capable_write,
265 	.llseek		= default_llseek,
266 };
267 
268 static int vhci_setup(struct hci_dev *hdev)
269 {
270 	struct vhci_data *vhci = hci_get_drvdata(hdev);
271 
272 	if (vhci->msft_opcode)
273 		hci_set_msft_opcode(hdev, vhci->msft_opcode);
274 
275 	if (vhci->aosp_capable)
276 		hci_set_aosp_capable(hdev);
277 
278 	return 0;
279 }
280 
281 static void vhci_coredump(struct hci_dev *hdev)
282 {
283 	/* No need to do anything */
284 }
285 
286 static void vhci_coredump_hdr(struct hci_dev *hdev, struct sk_buff *skb)
287 {
288 	char buf[80];
289 
290 	snprintf(buf, sizeof(buf), "Controller Name: vhci_ctrl\n");
291 	skb_put_data(skb, buf, strlen(buf));
292 
293 	snprintf(buf, sizeof(buf), "Firmware Version: vhci_fw\n");
294 	skb_put_data(skb, buf, strlen(buf));
295 
296 	snprintf(buf, sizeof(buf), "Driver: vhci_drv\n");
297 	skb_put_data(skb, buf, strlen(buf));
298 
299 	snprintf(buf, sizeof(buf), "Vendor: vhci\n");
300 	skb_put_data(skb, buf, strlen(buf));
301 }
302 
303 #define MAX_COREDUMP_LINE_LEN	40
304 
305 struct devcoredump_test_data {
306 	enum devcoredump_state state;
307 	unsigned int timeout;
308 	char data[MAX_COREDUMP_LINE_LEN];
309 };
310 
311 static inline void force_devcd_timeout(struct hci_dev *hdev,
312 				       unsigned int timeout)
313 {
314 #ifdef CONFIG_DEV_COREDUMP
315 	hdev->dump.timeout = msecs_to_jiffies(timeout * 1000);
316 #endif
317 }
318 
319 static ssize_t force_devcd_write(struct file *file, const char __user *user_buf,
320 				 size_t count, loff_t *ppos)
321 {
322 	struct vhci_data *data = file->private_data;
323 	struct hci_dev *hdev = data->hdev;
324 	struct sk_buff *skb = NULL;
325 	struct devcoredump_test_data dump_data;
326 	size_t data_size;
327 	int ret;
328 
329 	if (count < offsetof(struct devcoredump_test_data, data) ||
330 	    count > sizeof(dump_data))
331 		return -EINVAL;
332 
333 	if (copy_from_user(&dump_data, user_buf, count))
334 		return -EFAULT;
335 
336 	data_size = count - offsetof(struct devcoredump_test_data, data);
337 	skb = alloc_skb(data_size, GFP_ATOMIC);
338 	if (!skb)
339 		return -ENOMEM;
340 	skb_put_data(skb, &dump_data.data, data_size);
341 
342 	hci_devcd_register(hdev, vhci_coredump, vhci_coredump_hdr, NULL);
343 
344 	/* Force the devcoredump timeout */
345 	if (dump_data.timeout)
346 		force_devcd_timeout(hdev, dump_data.timeout);
347 
348 	ret = hci_devcd_init(hdev, skb->len);
349 	if (ret) {
350 		BT_ERR("Failed to generate devcoredump");
351 		kfree_skb(skb);
352 		return ret;
353 	}
354 
355 	hci_devcd_append(hdev, skb);
356 
357 	switch (dump_data.state) {
358 	case HCI_DEVCOREDUMP_DONE:
359 		hci_devcd_complete(hdev);
360 		break;
361 	case HCI_DEVCOREDUMP_ABORT:
362 		hci_devcd_abort(hdev);
363 		break;
364 	case HCI_DEVCOREDUMP_TIMEOUT:
365 		/* Do nothing */
366 		break;
367 	default:
368 		return -EINVAL;
369 	}
370 
371 	return count;
372 }
373 
374 static const struct file_operations force_devcoredump_fops = {
375 	.open		= simple_open,
376 	.write		= force_devcd_write,
377 };
378 
379 static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
380 {
381 	struct hci_dev *hdev;
382 	struct sk_buff *skb;
383 	__u8 dev_type;
384 
385 	if (data->hdev)
386 		return -EBADFD;
387 
388 	/* bits 0-1 are dev_type (Primary or AMP) */
389 	dev_type = opcode & 0x03;
390 
391 	if (dev_type != HCI_PRIMARY && dev_type != HCI_AMP)
392 		return -EINVAL;
393 
394 	/* bits 2-5 are reserved (must be zero) */
395 	if (opcode & 0x3c)
396 		return -EINVAL;
397 
398 	skb = bt_skb_alloc(4, GFP_KERNEL);
399 	if (!skb)
400 		return -ENOMEM;
401 
402 	hdev = hci_alloc_dev();
403 	if (!hdev) {
404 		kfree_skb(skb);
405 		return -ENOMEM;
406 	}
407 
408 	data->hdev = hdev;
409 
410 	hdev->bus = HCI_VIRTUAL;
411 	hdev->dev_type = dev_type;
412 	hci_set_drvdata(hdev, data);
413 
414 	hdev->open  = vhci_open_dev;
415 	hdev->close = vhci_close_dev;
416 	hdev->flush = vhci_flush;
417 	hdev->send  = vhci_send_frame;
418 	hdev->get_data_path_id = vhci_get_data_path_id;
419 	hdev->get_codec_config_data = vhci_get_codec_config_data;
420 	hdev->wakeup = vhci_wakeup;
421 	hdev->setup = vhci_setup;
422 	set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
423 
424 	/* bit 6 is for external configuration */
425 	if (opcode & 0x40)
426 		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
427 
428 	/* bit 7 is for raw device */
429 	if (opcode & 0x80)
430 		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
431 
432 	set_bit(HCI_QUIRK_VALID_LE_STATES, &hdev->quirks);
433 
434 	if (hci_register_dev(hdev) < 0) {
435 		BT_ERR("Can't register HCI device");
436 		hci_free_dev(hdev);
437 		data->hdev = NULL;
438 		kfree_skb(skb);
439 		return -EBUSY;
440 	}
441 
442 	debugfs_create_file("force_suspend", 0644, hdev->debugfs, data,
443 			    &force_suspend_fops);
444 
445 	debugfs_create_file("force_wakeup", 0644, hdev->debugfs, data,
446 			    &force_wakeup_fops);
447 
448 	if (IS_ENABLED(CONFIG_BT_MSFTEXT))
449 		debugfs_create_file("msft_opcode", 0644, hdev->debugfs, data,
450 				    &msft_opcode_fops);
451 
452 	if (IS_ENABLED(CONFIG_BT_AOSPEXT))
453 		debugfs_create_file("aosp_capable", 0644, hdev->debugfs, data,
454 				    &aosp_capable_fops);
455 
456 	debugfs_create_file("force_devcoredump", 0644, hdev->debugfs, data,
457 			    &force_devcoredump_fops);
458 
459 	hci_skb_pkt_type(skb) = HCI_VENDOR_PKT;
460 
461 	skb_put_u8(skb, 0xff);
462 	skb_put_u8(skb, opcode);
463 	put_unaligned_le16(hdev->id, skb_put(skb, 2));
464 	skb_queue_tail(&data->readq, skb);
465 
466 	wake_up_interruptible(&data->read_wait);
467 	return 0;
468 }
469 
470 static int vhci_create_device(struct vhci_data *data, __u8 opcode)
471 {
472 	int err;
473 
474 	mutex_lock(&data->open_mutex);
475 	err = __vhci_create_device(data, opcode);
476 	mutex_unlock(&data->open_mutex);
477 
478 	return err;
479 }
480 
481 static inline ssize_t vhci_get_user(struct vhci_data *data,
482 				    struct iov_iter *from)
483 {
484 	size_t len = iov_iter_count(from);
485 	struct sk_buff *skb;
486 	__u8 pkt_type, opcode;
487 	int ret;
488 
489 	if (len < 2 || len > HCI_MAX_FRAME_SIZE)
490 		return -EINVAL;
491 
492 	skb = bt_skb_alloc(len, GFP_KERNEL);
493 	if (!skb)
494 		return -ENOMEM;
495 
496 	if (!copy_from_iter_full(skb_put(skb, len), len, from)) {
497 		kfree_skb(skb);
498 		return -EFAULT;
499 	}
500 
501 	pkt_type = *((__u8 *) skb->data);
502 	skb_pull(skb, 1);
503 
504 	switch (pkt_type) {
505 	case HCI_EVENT_PKT:
506 	case HCI_ACLDATA_PKT:
507 	case HCI_SCODATA_PKT:
508 	case HCI_ISODATA_PKT:
509 		if (!data->hdev) {
510 			kfree_skb(skb);
511 			return -ENODEV;
512 		}
513 
514 		hci_skb_pkt_type(skb) = pkt_type;
515 
516 		ret = hci_recv_frame(data->hdev, skb);
517 		break;
518 
519 	case HCI_VENDOR_PKT:
520 		cancel_delayed_work_sync(&data->open_timeout);
521 
522 		opcode = *((__u8 *) skb->data);
523 		skb_pull(skb, 1);
524 
525 		if (skb->len > 0) {
526 			kfree_skb(skb);
527 			return -EINVAL;
528 		}
529 
530 		kfree_skb(skb);
531 
532 		ret = vhci_create_device(data, opcode);
533 		break;
534 
535 	default:
536 		kfree_skb(skb);
537 		return -EINVAL;
538 	}
539 
540 	return (ret < 0) ? ret : len;
541 }
542 
543 static inline ssize_t vhci_put_user(struct vhci_data *data,
544 				    struct sk_buff *skb,
545 				    char __user *buf, int count)
546 {
547 	char __user *ptr = buf;
548 	int len;
549 
550 	len = min_t(unsigned int, skb->len, count);
551 
552 	if (copy_to_user(ptr, skb->data, len))
553 		return -EFAULT;
554 
555 	if (!data->hdev)
556 		return len;
557 
558 	data->hdev->stat.byte_tx += len;
559 
560 	switch (hci_skb_pkt_type(skb)) {
561 	case HCI_COMMAND_PKT:
562 		data->hdev->stat.cmd_tx++;
563 		break;
564 	case HCI_ACLDATA_PKT:
565 		data->hdev->stat.acl_tx++;
566 		break;
567 	case HCI_SCODATA_PKT:
568 		data->hdev->stat.sco_tx++;
569 		break;
570 	}
571 
572 	return len;
573 }
574 
575 static ssize_t vhci_read(struct file *file,
576 			 char __user *buf, size_t count, loff_t *pos)
577 {
578 	struct vhci_data *data = file->private_data;
579 	struct sk_buff *skb;
580 	ssize_t ret = 0;
581 
582 	while (count) {
583 		skb = skb_dequeue(&data->readq);
584 		if (skb) {
585 			ret = vhci_put_user(data, skb, buf, count);
586 			if (ret < 0)
587 				skb_queue_head(&data->readq, skb);
588 			else
589 				kfree_skb(skb);
590 			break;
591 		}
592 
593 		if (file->f_flags & O_NONBLOCK) {
594 			ret = -EAGAIN;
595 			break;
596 		}
597 
598 		ret = wait_event_interruptible(data->read_wait,
599 					       !skb_queue_empty(&data->readq));
600 		if (ret < 0)
601 			break;
602 	}
603 
604 	return ret;
605 }
606 
607 static ssize_t vhci_write(struct kiocb *iocb, struct iov_iter *from)
608 {
609 	struct file *file = iocb->ki_filp;
610 	struct vhci_data *data = file->private_data;
611 
612 	return vhci_get_user(data, from);
613 }
614 
615 static __poll_t vhci_poll(struct file *file, poll_table *wait)
616 {
617 	struct vhci_data *data = file->private_data;
618 
619 	poll_wait(file, &data->read_wait, wait);
620 
621 	if (!skb_queue_empty(&data->readq))
622 		return EPOLLIN | EPOLLRDNORM;
623 
624 	return EPOLLOUT | EPOLLWRNORM;
625 }
626 
627 static void vhci_open_timeout(struct work_struct *work)
628 {
629 	struct vhci_data *data = container_of(work, struct vhci_data,
630 					      open_timeout.work);
631 
632 	vhci_create_device(data, amp ? HCI_AMP : HCI_PRIMARY);
633 }
634 
635 static int vhci_open(struct inode *inode, struct file *file)
636 {
637 	struct vhci_data *data;
638 
639 	data = kzalloc(sizeof(struct vhci_data), GFP_KERNEL);
640 	if (!data)
641 		return -ENOMEM;
642 
643 	skb_queue_head_init(&data->readq);
644 	init_waitqueue_head(&data->read_wait);
645 
646 	mutex_init(&data->open_mutex);
647 	INIT_DELAYED_WORK(&data->open_timeout, vhci_open_timeout);
648 	INIT_WORK(&data->suspend_work, vhci_suspend_work);
649 
650 	file->private_data = data;
651 	nonseekable_open(inode, file);
652 
653 	schedule_delayed_work(&data->open_timeout, msecs_to_jiffies(1000));
654 
655 	return 0;
656 }
657 
658 static int vhci_release(struct inode *inode, struct file *file)
659 {
660 	struct vhci_data *data = file->private_data;
661 	struct hci_dev *hdev;
662 
663 	cancel_delayed_work_sync(&data->open_timeout);
664 	flush_work(&data->suspend_work);
665 
666 	hdev = data->hdev;
667 
668 	if (hdev) {
669 		hci_unregister_dev(hdev);
670 		hci_free_dev(hdev);
671 	}
672 
673 	skb_queue_purge(&data->readq);
674 	file->private_data = NULL;
675 	kfree(data);
676 
677 	return 0;
678 }
679 
680 static const struct file_operations vhci_fops = {
681 	.owner		= THIS_MODULE,
682 	.read		= vhci_read,
683 	.write_iter	= vhci_write,
684 	.poll		= vhci_poll,
685 	.open		= vhci_open,
686 	.release	= vhci_release,
687 	.llseek		= no_llseek,
688 };
689 
690 static struct miscdevice vhci_miscdev = {
691 	.name	= "vhci",
692 	.fops	= &vhci_fops,
693 	.minor	= VHCI_MINOR,
694 };
695 module_misc_device(vhci_miscdev);
696 
697 module_param(amp, bool, 0644);
698 MODULE_PARM_DESC(amp, "Create AMP controller device");
699 
700 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
701 MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
702 MODULE_VERSION(VERSION);
703 MODULE_LICENSE("GPL");
704 MODULE_ALIAS("devname:vhci");
705 MODULE_ALIAS_MISCDEV(VHCI_MINOR);
706