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hci_vhci.c

/*
 *
 *  Bluetooth virtual HCI driver
 *
 *  Copyright (C) 2000-2001  Qualcomm Incorporated
 *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
 *  Copyright (C) 2004-2006  Marcel Holtmann <marcel@holtmann.org>
 *
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/poll.h>

#include <linux/skbuff.h>
#include <linux/miscdevice.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>

#ifndef CONFIG_BT_HCIVHCI_DEBUG
#undef  BT_DBG
#define BT_DBG(D...)
#endif

#define VERSION "1.2"

static int minor = MISC_DYNAMIC_MINOR;

struct vhci_data {
      struct hci_dev *hdev;

      unsigned long flags;

      wait_queue_head_t read_wait;
      struct sk_buff_head readq;

      struct fasync_struct *fasync;
};

#define VHCI_FASYNC     0x0010

static struct miscdevice vhci_miscdev;

static int vhci_open_dev(struct hci_dev *hdev)
{
      set_bit(HCI_RUNNING, &hdev->flags);

      return 0;
}

static int vhci_close_dev(struct hci_dev *hdev)
{
      struct vhci_data *data = hdev->driver_data;

      if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
            return 0;

      skb_queue_purge(&data->readq);

      return 0;
}

static int vhci_flush(struct hci_dev *hdev)
{
      struct vhci_data *data = hdev->driver_data;

      skb_queue_purge(&data->readq);

      return 0;
}

static int vhci_send_frame(struct sk_buff *skb)
{
      struct hci_dev* hdev = (struct hci_dev *) skb->dev;
      struct vhci_data *data;

      if (!hdev) {
            BT_ERR("Frame for unknown HCI device (hdev=NULL)");
            return -ENODEV;
      }

      if (!test_bit(HCI_RUNNING, &hdev->flags))
            return -EBUSY;

      data = hdev->driver_data;

      memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
      skb_queue_tail(&data->readq, skb);

      if (data->flags & VHCI_FASYNC)
            kill_fasync(&data->fasync, SIGIO, POLL_IN);

      wake_up_interruptible(&data->read_wait);

      return 0;
}

static void vhci_destruct(struct hci_dev *hdev)
{
      kfree(hdev->driver_data);
}

static inline ssize_t vhci_get_user(struct vhci_data *data,
                              const char __user *buf, size_t count)
{
      struct sk_buff *skb;

      if (count > HCI_MAX_FRAME_SIZE)
            return -EINVAL;

      skb = bt_skb_alloc(count, GFP_KERNEL);
      if (!skb)
            return -ENOMEM;

      if (copy_from_user(skb_put(skb, count), buf, count)) {
            kfree_skb(skb);
            return -EFAULT;
      }

      skb->dev = (void *) data->hdev;
      bt_cb(skb)->pkt_type = *((__u8 *) skb->data);
      skb_pull(skb, 1);

      hci_recv_frame(skb);

      return count;
}

static inline ssize_t vhci_put_user(struct vhci_data *data,
                  struct sk_buff *skb, char __user *buf, int count)
{
      char __user *ptr = buf;
      int len, total = 0;

      len = min_t(unsigned int, skb->len, count);

      if (copy_to_user(ptr, skb->data, len))
            return -EFAULT;

      total += len;

      data->hdev->stat.byte_tx += len;

      switch (bt_cb(skb)->pkt_type) {
      case HCI_COMMAND_PKT:
            data->hdev->stat.cmd_tx++;
            break;

      case HCI_ACLDATA_PKT:
            data->hdev->stat.acl_tx++;
            break;

      case HCI_SCODATA_PKT:
            data->hdev->stat.cmd_tx++;
            break;
      };

      return total;
}

static ssize_t vhci_read(struct file *file,
                        char __user *buf, size_t count, loff_t *pos)
{
      DECLARE_WAITQUEUE(wait, current);
      struct vhci_data *data = file->private_data;
      struct sk_buff *skb;
      ssize_t ret = 0;

      add_wait_queue(&data->read_wait, &wait);
      while (count) {
            set_current_state(TASK_INTERRUPTIBLE);

            skb = skb_dequeue(&data->readq);
            if (!skb) {
                  if (file->f_flags & O_NONBLOCK) {
                        ret = -EAGAIN;
                        break;
                  }

                  if (signal_pending(current)) {
                        ret = -ERESTARTSYS;
                        break;
                  }

                  schedule();
                  continue;
            }

            if (access_ok(VERIFY_WRITE, buf, count))
                  ret = vhci_put_user(data, skb, buf, count);
            else
                  ret = -EFAULT;

            kfree_skb(skb);
            break;
      }
      set_current_state(TASK_RUNNING);
      remove_wait_queue(&data->read_wait, &wait);

      return ret;
}

static ssize_t vhci_write(struct file *file,
                  const char __user *buf, size_t count, loff_t *pos)
{
      struct vhci_data *data = file->private_data;

      if (!access_ok(VERIFY_READ, buf, count))
            return -EFAULT;

      return vhci_get_user(data, buf, count);
}

static unsigned int vhci_poll(struct file *file, poll_table *wait)
{
      struct vhci_data *data = file->private_data;

      poll_wait(file, &data->read_wait, wait);

      if (!skb_queue_empty(&data->readq))
            return POLLIN | POLLRDNORM;

      return POLLOUT | POLLWRNORM;
}

static int vhci_ioctl(struct inode *inode, struct file *file,
                              unsigned int cmd, unsigned long arg)
{
      return -EINVAL;
}

static int vhci_open(struct inode *inode, struct file *file)
{
      struct vhci_data *data;
      struct hci_dev *hdev;

      data = kzalloc(sizeof(struct vhci_data), GFP_KERNEL);
      if (!data)
            return -ENOMEM;

      skb_queue_head_init(&data->readq);
      init_waitqueue_head(&data->read_wait);

      hdev = hci_alloc_dev();
      if (!hdev) {
            kfree(data);
            return -ENOMEM;
      }

      data->hdev = hdev;

      hdev->type = HCI_VIRTUAL;
      hdev->driver_data = data;

      hdev->open     = vhci_open_dev;
      hdev->close    = vhci_close_dev;
      hdev->flush    = vhci_flush;
      hdev->send     = vhci_send_frame;
      hdev->destruct = vhci_destruct;

      hdev->owner = THIS_MODULE;

      if (hci_register_dev(hdev) < 0) {
            BT_ERR("Can't register HCI device");
            kfree(data);
            hci_free_dev(hdev);
            return -EBUSY;
      }

      file->private_data = data;

      return nonseekable_open(inode, file);
}

static int vhci_release(struct inode *inode, struct file *file)
{
      struct vhci_data *data = file->private_data;
      struct hci_dev *hdev = data->hdev;

      if (hci_unregister_dev(hdev) < 0) {
            BT_ERR("Can't unregister HCI device %s", hdev->name);
      }

      hci_free_dev(hdev);

      file->private_data = NULL;

      return 0;
}

static int vhci_fasync(int fd, struct file *file, int on)
{
      struct vhci_data *data = file->private_data;
      int err;

      err = fasync_helper(fd, file, on, &data->fasync);
      if (err < 0)
            return err;

      if (on)
            data->flags |= VHCI_FASYNC;
      else
            data->flags &= ~VHCI_FASYNC;

      return 0;
}

static const struct file_operations vhci_fops = {
      .owner            = THIS_MODULE,
      .read       = vhci_read,
      .write            = vhci_write,
      .poll       = vhci_poll,
      .ioctl            = vhci_ioctl,
      .open       = vhci_open,
      .release    = vhci_release,
      .fasync           = vhci_fasync,
};

static struct miscdevice vhci_miscdev= {
      .name       = "vhci",
      .fops       = &vhci_fops,
};

static int __init vhci_init(void)
{
      BT_INFO("Virtual HCI driver ver %s", VERSION);

      vhci_miscdev.minor = minor;

      if (misc_register(&vhci_miscdev) < 0) {
            BT_ERR("Can't register misc device with minor %d", minor);
            return -EIO;
      }

      return 0;
}

static void __exit vhci_exit(void)
{
      if (misc_deregister(&vhci_miscdev) < 0)
            BT_ERR("Can't unregister misc device with minor %d", minor);
}

module_init(vhci_init);
module_exit(vhci_exit);

module_param(minor, int, 0444);
MODULE_PARM_DESC(minor, "Miscellaneous minor device number");

MODULE_AUTHOR("Maxim Krasnyansky <maxk@qualcomm.com>, Marcel Holtmann <marcel@holtmann.org>");
MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL");

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