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