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
vhci_open_dev(struct hci_dev * hdev)42 static int vhci_open_dev(struct hci_dev *hdev)
43 {
44 return 0;
45 }
46
vhci_close_dev(struct hci_dev * hdev)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
vhci_flush(struct hci_dev * hdev)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
vhci_send_frame(struct hci_dev * hdev,struct sk_buff * skb)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
__vhci_create_device(struct vhci_data * data,__u8 opcode)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
vhci_create_device(struct vhci_data * data,__u8 opcode)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
vhci_get_user(struct vhci_data * data,struct iov_iter * from)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
vhci_put_user(struct vhci_data * data,struct sk_buff * skb,char __user * buf,int count)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
vhci_read(struct file * file,char __user * buf,size_t count,loff_t * pos)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
vhci_write(struct kiocb * iocb,struct iov_iter * from)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
vhci_poll(struct file * file,poll_table * wait)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
vhci_open_timeout(struct work_struct * work)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
vhci_open(struct inode * inode,struct file * file)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
vhci_release(struct inode * inode,struct file * file)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
