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