hci_vhci.c

  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
 32static bool amp;
 33
 34struct 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
 51static int vhci_open_dev(struct hci_dev *hdev)
 52{
 53	return 0;
 54}
 55
 56static 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
 65static 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
 74static 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
 87static 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
 93static 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
105static bool vhci_wakeup(struct hci_dev *hdev)
106{
107	struct vhci_data *data = hci_get_drvdata(hdev);
108
109	return data->wakeup;
110}
111
112static 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
124static 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
135static 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
157static 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
164static 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
176static 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
196static 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
203static 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
218static 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
227DEFINE_DEBUGFS_ATTRIBUTE(msft_opcode_fops, msft_opcode_get, msft_opcode_set,
228			 "%llu\n");
229
230static 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
242static 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
265static 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
272static 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
285static void vhci_coredump(struct hci_dev *hdev)
286{
287	/* No need to do anything */
288}
289
290static void vhci_coredump_hdr(struct hci_dev *hdev, struct sk_buff *skb)
291{
292	const char *buf;
293
294	buf = "Controller Name: vhci_ctrl\n";
295	skb_put_data(skb, buf, strlen(buf));
296
297	buf = "Firmware Version: vhci_fw\n";
298	skb_put_data(skb, buf, strlen(buf));
299
300	buf = "Driver: vhci_drv\n";
301	skb_put_data(skb, buf, strlen(buf));
302
303	buf = "Vendor: vhci\n";
304	skb_put_data(skb, buf, strlen(buf));
305}
306
307#define MAX_COREDUMP_LINE_LEN	40
308
309struct devcoredump_test_data {
310	enum devcoredump_state state;
311	unsigned int timeout;
312	char data[MAX_COREDUMP_LINE_LEN];
313};
314
315static inline void force_devcd_timeout(struct hci_dev *hdev,
316				       unsigned int timeout)
317{
318#ifdef CONFIG_DEV_COREDUMP
319	hdev->dump.timeout = secs_to_jiffies(timeout);
320#endif
321}
322
323static 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
378static const struct file_operations force_devcoredump_fops = {
379	.open		= simple_open,
380	.write		= force_devcd_write,
381};
382
383static void vhci_debugfs_init(struct vhci_data *data)
384{
385	struct hci_dev *hdev = data->hdev;
386
387	debugfs_create_file("force_suspend", 0644, hdev->debugfs, data,
388			    &force_suspend_fops);
389
390	debugfs_create_file("force_wakeup", 0644, hdev->debugfs, data,
391			    &force_wakeup_fops);
392
393	if (IS_ENABLED(CONFIG_BT_MSFTEXT))
394		debugfs_create_file("msft_opcode", 0644, hdev->debugfs, data,
395				    &msft_opcode_fops);
396
397	if (IS_ENABLED(CONFIG_BT_AOSPEXT))
398		debugfs_create_file("aosp_capable", 0644, hdev->debugfs, data,
399				    &aosp_capable_fops);
400
401	debugfs_create_file("force_devcoredump", 0644, hdev->debugfs, data,
402			    &force_devcoredump_fops);
403}
404
405static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
406{
407	struct hci_dev *hdev;
408	struct sk_buff *skb;
409
410	if (data->hdev)
411		return -EBADFD;
412
413	/* bits 2-5 are reserved (must be zero) */
414	if (opcode & 0x3c)
415		return -EINVAL;
416
417	skb = bt_skb_alloc(4, GFP_KERNEL);
418	if (!skb)
419		return -ENOMEM;
420
421	hdev = hci_alloc_dev();
422	if (!hdev) {
423		kfree_skb(skb);
424		return -ENOMEM;
425	}
426
427	data->hdev = hdev;
428
429	hdev->bus = HCI_VIRTUAL;
430	hci_set_drvdata(hdev, data);
431
432	hdev->open  = vhci_open_dev;
433	hdev->close = vhci_close_dev;
434	hdev->flush = vhci_flush;
435	hdev->send  = vhci_send_frame;
436	hdev->get_data_path_id = vhci_get_data_path_id;
437	hdev->get_codec_config_data = vhci_get_codec_config_data;
438	hdev->wakeup = vhci_wakeup;
439	hdev->setup = vhci_setup;
440	hci_set_quirk(hdev, HCI_QUIRK_NON_PERSISTENT_SETUP);
441	hci_set_quirk(hdev, HCI_QUIRK_SYNC_FLOWCTL_SUPPORTED);
442
443	/* bit 6 is for external configuration */
444	if (opcode & 0x40)
445		hci_set_quirk(hdev, HCI_QUIRK_EXTERNAL_CONFIG);
446
447	/* bit 7 is for raw device */
448	if (opcode & 0x80)
449		hci_set_quirk(hdev, HCI_QUIRK_RAW_DEVICE);
450
451	if (hci_register_dev(hdev) < 0) {
452		BT_ERR("Can't register HCI device");
453		hci_free_dev(hdev);
454		data->hdev = NULL;
455		kfree_skb(skb);
456		return -EBUSY;
457	}
458
459	if (!IS_ERR_OR_NULL(hdev->debugfs))
460		vhci_debugfs_init(data);
461
462	hci_skb_pkt_type(skb) = HCI_VENDOR_PKT;
463
464	skb_put_u8(skb, 0xff);
465	skb_put_u8(skb, opcode);
466	put_unaligned_le16(hdev->id, skb_put(skb, 2));
467	skb_queue_head(&data->readq, skb);
468	atomic_inc(&data->initialized);
469
470	wake_up_interruptible(&data->read_wait);
471	return 0;
472}
473
474static int vhci_create_device(struct vhci_data *data, __u8 opcode)
475{
476	int err;
477
478	mutex_lock(&data->open_mutex);
479	err = __vhci_create_device(data, opcode);
480	mutex_unlock(&data->open_mutex);
481
482	return err;
483}
484
485static inline ssize_t vhci_get_user(struct vhci_data *data,
486				    struct iov_iter *from)
487{
488	size_t len = iov_iter_count(from);
489	struct sk_buff *skb;
490	__u8 pkt_type, opcode;
491	int ret;
492
493	if (len < 2 || len > HCI_MAX_FRAME_SIZE)
494		return -EINVAL;
495
496	skb = bt_skb_alloc(len, GFP_KERNEL);
497	if (!skb)
498		return -ENOMEM;
499
500	if (!copy_from_iter_full(skb_put(skb, len), len, from)) {
501		kfree_skb(skb);
502		return -EFAULT;
503	}
504
505	pkt_type = *((__u8 *) skb->data);
506	skb_pull(skb, 1);
507
508	switch (pkt_type) {
509	case HCI_EVENT_PKT:
510	case HCI_ACLDATA_PKT:
511	case HCI_SCODATA_PKT:
512	case HCI_ISODATA_PKT:
513		if (!data->hdev) {
514			kfree_skb(skb);
515			return -ENODEV;
516		}
517
518		hci_skb_pkt_type(skb) = pkt_type;
519
520		ret = hci_recv_frame(data->hdev, skb);
521		break;
522
523	case HCI_VENDOR_PKT:
524		cancel_delayed_work_sync(&data->open_timeout);
525
526		opcode = *((__u8 *) skb->data);
527		skb_pull(skb, 1);
528
529		if (skb->len > 0) {
530			kfree_skb(skb);
531			return -EINVAL;
532		}
533
534		kfree_skb(skb);
535
536		ret = vhci_create_device(data, opcode);
537		break;
538
539	default:
540		kfree_skb(skb);
541		return -EINVAL;
542	}
543
544	return (ret < 0) ? ret : len;
545}
546
547static inline ssize_t vhci_put_user(struct vhci_data *data,
548				    struct sk_buff *skb,
549				    char __user *buf, int count)
550{
551	char __user *ptr = buf;
552	int len;
553
554	len = min_t(unsigned int, skb->len, count);
555
556	if (copy_to_user(ptr, skb->data, len))
557		return -EFAULT;
558
559	if (!data->hdev)
560		return len;
561
562	data->hdev->stat.byte_tx += len;
563
564	switch (hci_skb_pkt_type(skb)) {
565	case HCI_COMMAND_PKT:
566		data->hdev->stat.cmd_tx++;
567		break;
568	case HCI_ACLDATA_PKT:
569		data->hdev->stat.acl_tx++;
570		break;
571	case HCI_SCODATA_PKT:
572		data->hdev->stat.sco_tx++;
573		break;
574	}
575
576	return len;
577}
578
579static ssize_t vhci_read(struct file *file,
580			 char __user *buf, size_t count, loff_t *pos)
581{
582	struct vhci_data *data = file->private_data;
583	struct sk_buff *skb;
584	ssize_t ret = 0;
585
586	while (count) {
587		skb = skb_dequeue(&data->readq);
588		if (skb) {
589			ret = vhci_put_user(data, skb, buf, count);
590			if (ret < 0)
591				skb_queue_head(&data->readq, skb);
592			else
593				kfree_skb(skb);
594			break;
595		}
596
597		if (file->f_flags & O_NONBLOCK) {
598			ret = -EAGAIN;
599			break;
600		}
601
602		ret = wait_event_interruptible(data->read_wait,
603					       !skb_queue_empty(&data->readq));
604		if (ret < 0)
605			break;
606	}
607
608	return ret;
609}
610
611static ssize_t vhci_write(struct kiocb *iocb, struct iov_iter *from)
612{
613	struct file *file = iocb->ki_filp;
614	struct vhci_data *data = file->private_data;
615
616	return vhci_get_user(data, from);
617}
618
619static __poll_t vhci_poll(struct file *file, poll_table *wait)
620{
621	struct vhci_data *data = file->private_data;
622
623	poll_wait(file, &data->read_wait, wait);
624
625	if (!skb_queue_empty(&data->readq))
626		return EPOLLIN | EPOLLRDNORM;
627
628	return EPOLLOUT | EPOLLWRNORM;
629}
630
631static void vhci_open_timeout(struct work_struct *work)
632{
633	struct vhci_data *data = container_of(work, struct vhci_data,
634					      open_timeout.work);
635
636	vhci_create_device(data, 0x00);
637}
638
639static int vhci_open(struct inode *inode, struct file *file)
640{
641	struct vhci_data *data;
642
643	data = kzalloc(sizeof(*data), GFP_KERNEL);
644	if (!data)
645		return -ENOMEM;
646
647	skb_queue_head_init(&data->readq);
648	init_waitqueue_head(&data->read_wait);
649
650	mutex_init(&data->open_mutex);
651	INIT_DELAYED_WORK(&data->open_timeout, vhci_open_timeout);
652	INIT_WORK(&data->suspend_work, vhci_suspend_work);
653
654	file->private_data = data;
655	nonseekable_open(inode, file);
656
657	schedule_delayed_work(&data->open_timeout, secs_to_jiffies(1));
658
659	return 0;
660}
661
662static void vhci_debugfs_remove(struct hci_dev *hdev)
663{
664	debugfs_lookup_and_remove("force_suspend", hdev->debugfs);
665
666	debugfs_lookup_and_remove("force_wakeup", hdev->debugfs);
667
668	if (IS_ENABLED(CONFIG_BT_MSFTEXT))
669		debugfs_lookup_and_remove("msft_opcode", hdev->debugfs);
670
671	if (IS_ENABLED(CONFIG_BT_AOSPEXT))
672		debugfs_lookup_and_remove("aosp_capable", hdev->debugfs);
673
674	debugfs_lookup_and_remove("force_devcoredump", hdev->debugfs);
675}
676
677static int vhci_release(struct inode *inode, struct file *file)
678{
679	struct vhci_data *data = file->private_data;
680	struct hci_dev *hdev;
681
682	cancel_delayed_work_sync(&data->open_timeout);
683	flush_work(&data->suspend_work);
684
685	hdev = data->hdev;
686
687	if (hdev) {
688		if (!IS_ERR_OR_NULL(hdev->debugfs))
689			vhci_debugfs_remove(hdev);
690		hci_unregister_dev(hdev);
691		hci_free_dev(hdev);
692	}
693
694	skb_queue_purge(&data->readq);
695	file->private_data = NULL;
696	kfree(data);
697
698	return 0;
699}
700
701static const struct file_operations vhci_fops = {
702	.owner		= THIS_MODULE,
703	.read		= vhci_read,
704	.write_iter	= vhci_write,
705	.poll		= vhci_poll,
706	.open		= vhci_open,
707	.release	= vhci_release,
708};
709
710static struct miscdevice vhci_miscdev = {
711	.name	= "vhci",
712	.fops	= &vhci_fops,
713	.minor	= VHCI_MINOR,
714};
715module_misc_device(vhci_miscdev);
716
717module_param(amp, bool, 0644);
718MODULE_PARM_DESC(amp, "Create AMP controller device");
719
720MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
721MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
722MODULE_VERSION(VERSION);
723MODULE_LICENSE("GPL");
724MODULE_ALIAS("devname:vhci");
725MODULE_ALIAS_MISCDEV(VHCI_MINOR);