hci_vhci.c

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/*
 *
 *  Bluetooth virtual HCI driver
 *
 *  Copyright (C) 2000-2001  Qualcomm Incorporated
 *  Copyright (C) 2002-2003  Maxim Krasnyansky <[email protected]>
 *  Copyright (C) 2004-2006  Marcel Holtmann <[email protected]>
 *
 *
 *  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>

#define VERSION "1.3"

static bool amp;

struct vhci_data {
    struct hci_dev *hdev;

    unsigned long flags;

    wait_queue_head_t read_wait;
    struct sk_buff_head readq;
};

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 = hci_get_drvdata(hdev);

    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 = hci_get_drvdata(hdev);

    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 = hci_get_drvdata(hdev);

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

    wake_up_interruptible(&data->read_wait);

    return 0;
}

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.sco_tx++;
        break;
    }

    return total;
}

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

    while (count) {
        skb = skb_dequeue(&data->readq);
        if (skb) {
            ret = vhci_put_user(data, skb, buf, count);
            if (ret < 0)
                skb_queue_head(&data->readq, skb);
            else
                kfree_skb(skb);
            break;
        }

        if (file->f_flags & O_NONBLOCK) {
            ret = -EAGAIN;
            break;
        }

        ret = wait_event_interruptible(data->read_wait,
                    !skb_queue_empty(&data->readq));
        if (ret < 0)
            break;
    }

    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;

    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_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->bus = HCI_VIRTUAL;
    hci_set_drvdata(hdev, data);

    if (amp)
        hdev->dev_type = HCI_AMP;

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

    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;
    nonseekable_open(inode, file);

    return 0;
}

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

    hci_unregister_dev(hdev);
    hci_free_dev(hdev);

    file->private_data = NULL;
    kfree(data);

    return 0;
}

static const struct file_operations vhci_fops = {
    .owner      = THIS_MODULE,
    .read       = vhci_read,
    .write      = vhci_write,
    .poll       = vhci_poll,
    .open       = vhci_open,
    .release    = vhci_release,
    .llseek     = no_llseek,
};

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

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

    return misc_register(&vhci_miscdev);
}

static void __exit vhci_exit(void)
{
    misc_deregister(&vhci_miscdev);
}

module_init(vhci_init);
module_exit(vhci_exit);

module_param(amp, bool, 0644);
MODULE_PARM_DESC(amp, "Create AMP controller device");

MODULE_AUTHOR("Marcel Holtmann <[email protected]>");
MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL");