xref: /openbmc/linux/drivers/bluetooth/hci_vhci.c (revision c4f7ac64) 
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 
25 #include <net/bluetooth/bluetooth.h>
26 #include <net/bluetooth/hci_core.h>
27 
28 #define VERSION "1.5"
29 
30 static bool amp;
31 
32 struct vhci_data {
33 	struct hci_dev *hdev;
34 
35 	wait_queue_head_t read_wait;
36 	struct sk_buff_head readq;
37 
38 	struct mutex open_mutex;
39 	struct delayed_work open_timeout;
40 };
41 
42 static int vhci_open_dev(struct hci_dev *hdev)
43 {
44 	return 0;
45 }
46 
47 static int vhci_close_dev(struct hci_dev *hdev)
48 {
49 	struct vhci_data *data = hci_get_drvdata(hdev);
50 
51 	skb_queue_purge(&data->readq);
52 
53 	return 0;
54 }
55 
56 static int vhci_flush(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_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
66 {
67 	struct vhci_data *data = hci_get_drvdata(hdev);
68 
69 	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
70 	skb_queue_tail(&data->readq, skb);
71 
72 	wake_up_interruptible(&data->read_wait);
73 	return 0;
74 }
75 
76 static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
77 {
78 	struct hci_dev *hdev;
79 	struct sk_buff *skb;
80 	__u8 dev_type;
81 
82 	if (data->hdev)
83 		return -EBADFD;
84 
85 	/* bits 0-1 are dev_type (Primary or AMP) */
86 	dev_type = opcode & 0x03;
87 
88 	if (dev_type != HCI_PRIMARY && dev_type != HCI_AMP)
89 		return -EINVAL;
90 
91 	/* bits 2-5 are reserved (must be zero) */
92 	if (opcode & 0x3c)
93 		return -EINVAL;
94 
95 	skb = bt_skb_alloc(4, GFP_KERNEL);
96 	if (!skb)
97 		return -ENOMEM;
98 
99 	hdev = hci_alloc_dev();
100 	if (!hdev) {
101 		kfree_skb(skb);
102 		return -ENOMEM;
103 	}
104 
105 	data->hdev = hdev;
106 
107 	hdev->bus = HCI_VIRTUAL;
108 	hdev->dev_type = dev_type;
109 	hci_set_drvdata(hdev, data);
110 
111 	hdev->open  = vhci_open_dev;
112 	hdev->close = vhci_close_dev;
113 	hdev->flush = vhci_flush;
114 	hdev->send  = vhci_send_frame;
115 
116 	/* bit 6 is for external configuration */
117 	if (opcode & 0x40)
118 		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
119 
120 	/* bit 7 is for raw device */
121 	if (opcode & 0x80)
122 		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
123 
124 	if (hci_register_dev(hdev) < 0) {
125 		BT_ERR("Can't register HCI device");
126 		hci_free_dev(hdev);
127 		data->hdev = NULL;
128 		kfree_skb(skb);
129 		return -EBUSY;
130 	}
131 
132 	hci_skb_pkt_type(skb) = HCI_VENDOR_PKT;
133 
134 	skb_put_u8(skb, 0xff);
135 	skb_put_u8(skb, opcode);
136 	put_unaligned_le16(hdev->id, skb_put(skb, 2));
137 	skb_queue_tail(&data->readq, skb);
138 
139 	wake_up_interruptible(&data->read_wait);
140 	return 0;
141 }
142 
143 static int vhci_create_device(struct vhci_data *data, __u8 opcode)
144 {
145 	int err;
146 
147 	mutex_lock(&data->open_mutex);
148 	err = __vhci_create_device(data, opcode);
149 	mutex_unlock(&data->open_mutex);
150 
151 	return err;
152 }
153 
154 static inline ssize_t vhci_get_user(struct vhci_data *data,
155 				    struct iov_iter *from)
156 {
157 	size_t len = iov_iter_count(from);
158 	struct sk_buff *skb;
159 	__u8 pkt_type, opcode;
160 	int ret;
161 
162 	if (len < 2 || len > HCI_MAX_FRAME_SIZE)
163 		return -EINVAL;
164 
165 	skb = bt_skb_alloc(len, GFP_KERNEL);
166 	if (!skb)
167 		return -ENOMEM;
168 
169 	if (!copy_from_iter_full(skb_put(skb, len), len, from)) {
170 		kfree_skb(skb);
171 		return -EFAULT;
172 	}
173 
174 	pkt_type = *((__u8 *) skb->data);
175 	skb_pull(skb, 1);
176 
177 	switch (pkt_type) {
178 	case HCI_EVENT_PKT:
179 	case HCI_ACLDATA_PKT:
180 	case HCI_SCODATA_PKT:
181 	case HCI_ISODATA_PKT:
182 		if (!data->hdev) {
183 			kfree_skb(skb);
184 			return -ENODEV;
185 		}
186 
187 		hci_skb_pkt_type(skb) = pkt_type;
188 
189 		ret = hci_recv_frame(data->hdev, skb);
190 		break;
191 
192 	case HCI_VENDOR_PKT:
193 		cancel_delayed_work_sync(&data->open_timeout);
194 
195 		opcode = *((__u8 *) skb->data);
196 		skb_pull(skb, 1);
197 
198 		if (skb->len > 0) {
199 			kfree_skb(skb);
200 			return -EINVAL;
201 		}
202 
203 		kfree_skb(skb);
204 
205 		ret = vhci_create_device(data, opcode);
206 		break;
207 
208 	default:
209 		kfree_skb(skb);
210 		return -EINVAL;
211 	}
212 
213 	return (ret < 0) ? ret : len;
214 }
215 
216 static inline ssize_t vhci_put_user(struct vhci_data *data,
217 				    struct sk_buff *skb,
218 				    char __user *buf, int count)
219 {
220 	char __user *ptr = buf;
221 	int len;
222 
223 	len = min_t(unsigned int, skb->len, count);
224 
225 	if (copy_to_user(ptr, skb->data, len))
226 		return -EFAULT;
227 
228 	if (!data->hdev)
229 		return len;
230 
231 	data->hdev->stat.byte_tx += len;
232 
233 	switch (hci_skb_pkt_type(skb)) {
234 	case HCI_COMMAND_PKT:
235 		data->hdev->stat.cmd_tx++;
236 		break;
237 	case HCI_ACLDATA_PKT:
238 		data->hdev->stat.acl_tx++;
239 		break;
240 	case HCI_SCODATA_PKT:
241 		data->hdev->stat.sco_tx++;
242 		break;
243 	}
244 
245 	return len;
246 }
247 
248 static ssize_t vhci_read(struct file *file,
249 			 char __user *buf, size_t count, loff_t *pos)
250 {
251 	struct vhci_data *data = file->private_data;
252 	struct sk_buff *skb;
253 	ssize_t ret = 0;
254 
255 	while (count) {
256 		skb = skb_dequeue(&data->readq);
257 		if (skb) {
258 			ret = vhci_put_user(data, skb, buf, count);
259 			if (ret < 0)
260 				skb_queue_head(&data->readq, skb);
261 			else
262 				kfree_skb(skb);
263 			break;
264 		}
265 
266 		if (file->f_flags & O_NONBLOCK) {
267 			ret = -EAGAIN;
268 			break;
269 		}
270 
271 		ret = wait_event_interruptible(data->read_wait,
272 					       !skb_queue_empty(&data->readq));
273 		if (ret < 0)
274 			break;
275 	}
276 
277 	return ret;
278 }
279 
280 static ssize_t vhci_write(struct kiocb *iocb, struct iov_iter *from)
281 {
282 	struct file *file = iocb->ki_filp;
283 	struct vhci_data *data = file->private_data;
284 
285 	return vhci_get_user(data, from);
286 }
287 
288 static __poll_t vhci_poll(struct file *file, poll_table *wait)
289 {
290 	struct vhci_data *data = file->private_data;
291 
292 	poll_wait(file, &data->read_wait, wait);
293 
294 	if (!skb_queue_empty(&data->readq))
295 		return EPOLLIN | EPOLLRDNORM;
296 
297 	return EPOLLOUT | EPOLLWRNORM;
298 }
299 
300 static void vhci_open_timeout(struct work_struct *work)
301 {
302 	struct vhci_data *data = container_of(work, struct vhci_data,
303 					      open_timeout.work);
304 
305 	vhci_create_device(data, amp ? HCI_AMP : HCI_PRIMARY);
306 }
307 
308 static int vhci_open(struct inode *inode, struct file *file)
309 {
310 	struct vhci_data *data;
311 
312 	data = kzalloc(sizeof(struct vhci_data), GFP_KERNEL);
313 	if (!data)
314 		return -ENOMEM;
315 
316 	skb_queue_head_init(&data->readq);
317 	init_waitqueue_head(&data->read_wait);
318 
319 	mutex_init(&data->open_mutex);
320 	INIT_DELAYED_WORK(&data->open_timeout, vhci_open_timeout);
321 
322 	file->private_data = data;
323 	nonseekable_open(inode, file);
324 
325 	schedule_delayed_work(&data->open_timeout, msecs_to_jiffies(1000));
326 
327 	return 0;
328 }
329 
330 static int vhci_release(struct inode *inode, struct file *file)
331 {
332 	struct vhci_data *data = file->private_data;
333 	struct hci_dev *hdev;
334 
335 	cancel_delayed_work_sync(&data->open_timeout);
336 
337 	hdev = data->hdev;
338 
339 	if (hdev) {
340 		hci_unregister_dev(hdev);
341 		hci_free_dev(hdev);
342 	}
343 
344 	skb_queue_purge(&data->readq);
345 	file->private_data = NULL;
346 	kfree(data);
347 
348 	return 0;
349 }
350 
351 static const struct file_operations vhci_fops = {
352 	.owner		= THIS_MODULE,
353 	.read		= vhci_read,
354 	.write_iter	= vhci_write,
355 	.poll		= vhci_poll,
356 	.open		= vhci_open,
357 	.release	= vhci_release,
358 	.llseek		= no_llseek,
359 };
360 
361 static struct miscdevice vhci_miscdev = {
362 	.name	= "vhci",
363 	.fops	= &vhci_fops,
364 	.minor	= VHCI_MINOR,
365 };
366 module_misc_device(vhci_miscdev);
367 
368 module_param(amp, bool, 0644);
369 MODULE_PARM_DESC(amp, "Create AMP controller device");
370 
371 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
372 MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
373 MODULE_VERSION(VERSION);
374 MODULE_LICENSE("GPL");
375 MODULE_ALIAS("devname:vhci");
376 MODULE_ALIAS_MISCDEV(VHCI_MINOR);
377