[Bluetooth]: Call tty_hangup() when DCD is de-asserted

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / bluetooth / rfcomm / tty.c

/* 
   RFCOMM implementation for Linux Bluetooth stack (BlueZ).
   Copyright (C) 2002 Maxim Krasnyansky <maxk@qualcomm.com>
   Copyright (C) 2002 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 version 2 as
   published by the Free Software Foundation;

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES 
   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 
   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS, 
   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS 
   SOFTWARE IS DISCLAIMED.
*/

/*
 * RFCOMM TTY.
 *
 * $Id: tty.c,v 1.24 2002/10/03 01:54:38 holtmann Exp $
 */

#include <linux/config.h>
#include <linux/module.h>

#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>

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

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

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

#define RFCOMM_TTY_MAGIC 0x6d02		/* magic number for rfcomm struct */
#define RFCOMM_TTY_PORTS RFCOMM_MAX_DEV	/* whole lotta rfcomm devices */
#define RFCOMM_TTY_MAJOR 216		/* device node major id of the usb/bluetooth.c driver */
#define RFCOMM_TTY_MINOR 0

static struct tty_driver *rfcomm_tty_driver;

struct rfcomm_dev {
	struct list_head	list;
	atomic_t		refcnt;

	char			name[12];
	int			id;
	unsigned long		flags;
	int			opened;
	int			err;

	bdaddr_t		src;
	bdaddr_t		dst;
	u8 			channel;

	uint 			modem_status;

	struct rfcomm_dlc	*dlc;
	struct tty_struct	*tty;
	wait_queue_head_t       wait;
	struct tasklet_struct   wakeup_task;

	atomic_t 		wmem_alloc;
};

static LIST_HEAD(rfcomm_dev_list);
static DEFINE_RWLOCK(rfcomm_dev_lock);

static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb);
static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err);
static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig);

static void rfcomm_tty_wakeup(unsigned long arg);

/* ---- Device functions ---- */
static void rfcomm_dev_destruct(struct rfcomm_dev *dev)
{
	struct rfcomm_dlc *dlc = dev->dlc;

	BT_DBG("dev %p dlc %p", dev, dlc);

	rfcomm_dlc_lock(dlc);
	/* Detach DLC if it's owned by this dev */
	if (dlc->owner == dev)
		dlc->owner = NULL;
	rfcomm_dlc_unlock(dlc);

	rfcomm_dlc_put(dlc);

	tty_unregister_device(rfcomm_tty_driver, dev->id);

	/* Refcount should only hit zero when called from rfcomm_dev_del()
	   which will have taken us off the list. Everything else are
	   refcounting bugs. */
	BUG_ON(!list_empty(&dev->list));

	kfree(dev);

	/* It's safe to call module_put() here because socket still 
	   holds reference to this module. */
	module_put(THIS_MODULE);
}

static inline void rfcomm_dev_hold(struct rfcomm_dev *dev)
{
	atomic_inc(&dev->refcnt);
}

static inline void rfcomm_dev_put(struct rfcomm_dev *dev)
{
	/* The reason this isn't actually a race, as you no
	   doubt have a little voice screaming at you in your
	   head, is that the refcount should never actually
	   reach zero unless the device has already been taken
	   off the list, in rfcomm_dev_del(). And if that's not
	   true, we'll hit the BUG() in rfcomm_dev_destruct()
	   anyway. */
	if (atomic_dec_and_test(&dev->refcnt))
		rfcomm_dev_destruct(dev);
}

static struct rfcomm_dev *__rfcomm_dev_get(int id)
{
	struct rfcomm_dev *dev;
	struct list_head  *p;

	list_for_each(p, &rfcomm_dev_list) {
		dev = list_entry(p, struct rfcomm_dev, list);
		if (dev->id == id)
			return dev;
	}

	return NULL;
}

static inline struct rfcomm_dev *rfcomm_dev_get(int id)
{
	struct rfcomm_dev *dev;

	read_lock(&rfcomm_dev_lock);

	dev = __rfcomm_dev_get(id);
	if (dev)
		rfcomm_dev_hold(dev);

	read_unlock(&rfcomm_dev_lock);

	return dev;
}

static int rfcomm_dev_add(struct rfcomm_dev_req *req, struct rfcomm_dlc *dlc)
{
	struct rfcomm_dev *dev;
	struct list_head *head = &rfcomm_dev_list, *p;
	int err = 0;

	BT_DBG("id %d channel %d", req->dev_id, req->channel);
	
	dev = kmalloc(sizeof(struct rfcomm_dev), GFP_KERNEL);
	if (!dev)
		return -ENOMEM;
	memset(dev, 0, sizeof(struct rfcomm_dev));

	write_lock_bh(&rfcomm_dev_lock);

	if (req->dev_id < 0) {
		dev->id = 0;

		list_for_each(p, &rfcomm_dev_list) {
			if (list_entry(p, struct rfcomm_dev, list)->id != dev->id)
				break;

			dev->id++;
			head = p;
		}
	} else {
		dev->id = req->dev_id;

		list_for_each(p, &rfcomm_dev_list) {
			struct rfcomm_dev *entry = list_entry(p, struct rfcomm_dev, list);

			if (entry->id == dev->id) {
				err = -EADDRINUSE;
				goto out;
			}

			if (entry->id > dev->id - 1)
				break;

			head = p;
		}
	}

	if ((dev->id < 0) || (dev->id > RFCOMM_MAX_DEV - 1)) {
		err = -ENFILE;
		goto out;
	}

	sprintf(dev->name, "rfcomm%d", dev->id);

	list_add(&dev->list, head);
	atomic_set(&dev->refcnt, 1);

	bacpy(&dev->src, &req->src);
	bacpy(&dev->dst, &req->dst);
	dev->channel = req->channel;

	dev->flags = req->flags & 
		((1 << RFCOMM_RELEASE_ONHUP) | (1 << RFCOMM_REUSE_DLC));

	init_waitqueue_head(&dev->wait);
	tasklet_init(&dev->wakeup_task, rfcomm_tty_wakeup, (unsigned long) dev);

	rfcomm_dlc_lock(dlc);
	dlc->data_ready   = rfcomm_dev_data_ready;
	dlc->state_change = rfcomm_dev_state_change;
	dlc->modem_status = rfcomm_dev_modem_status;

	dlc->owner = dev;
	dev->dlc   = dlc;
	rfcomm_dlc_unlock(dlc);

	/* It's safe to call __module_get() here because socket already 
	   holds reference to this module. */
	__module_get(THIS_MODULE);

out:
	write_unlock_bh(&rfcomm_dev_lock);

	if (err) {
		kfree(dev);
		return err;
	}

	tty_register_device(rfcomm_tty_driver, dev->id, NULL);

	return dev->id;
}

static void rfcomm_dev_del(struct rfcomm_dev *dev)
{
	BT_DBG("dev %p", dev);

	write_lock_bh(&rfcomm_dev_lock);
	list_del_init(&dev->list);
	write_unlock_bh(&rfcomm_dev_lock);

	rfcomm_dev_put(dev);
}

/* ---- Send buffer ---- */
static inline unsigned int rfcomm_room(struct rfcomm_dlc *dlc)
{
	/* We can't let it be zero, because we don't get a callback
	   when tx_credits becomes nonzero, hence we'd never wake up */
	return dlc->mtu * (dlc->tx_credits?:1);
}

static void rfcomm_wfree(struct sk_buff *skb)
{
	struct rfcomm_dev *dev = (void *) skb->sk;
	atomic_sub(skb->truesize, &dev->wmem_alloc);
	if (test_bit(RFCOMM_TTY_ATTACHED, &dev->flags))
		tasklet_schedule(&dev->wakeup_task);
	rfcomm_dev_put(dev);
}

static inline void rfcomm_set_owner_w(struct sk_buff *skb, struct rfcomm_dev *dev)
{
	rfcomm_dev_hold(dev);
	atomic_add(skb->truesize, &dev->wmem_alloc);
	skb->sk = (void *) dev;
	skb->destructor = rfcomm_wfree;
}

static struct sk_buff *rfcomm_wmalloc(struct rfcomm_dev *dev, unsigned long size, int priority)
{
	if (atomic_read(&dev->wmem_alloc) < rfcomm_room(dev->dlc)) {
		struct sk_buff *skb = alloc_skb(size, priority);
		if (skb) {
			rfcomm_set_owner_w(skb, dev);
			return skb;
		}
	}
	return NULL;
}

/* ---- Device IOCTLs ---- */

#define NOCAP_FLAGS ((1 << RFCOMM_REUSE_DLC) | (1 << RFCOMM_RELEASE_ONHUP))

static int rfcomm_create_dev(struct sock *sk, void __user *arg)
{
	struct rfcomm_dev_req req;
	struct rfcomm_dlc *dlc;
	int id;

	if (copy_from_user(&req, arg, sizeof(req)))
		return -EFAULT;

	BT_DBG("sk %p dev_id %id flags 0x%x", sk, req.dev_id, req.flags);

	if (req.flags != NOCAP_FLAGS && !capable(CAP_NET_ADMIN))
		return -EPERM;

	if (req.flags & (1 << RFCOMM_REUSE_DLC)) {
		/* Socket must be connected */
		if (sk->sk_state != BT_CONNECTED)
			return -EBADFD;

		dlc = rfcomm_pi(sk)->dlc;
		rfcomm_dlc_hold(dlc);
	} else {
		dlc = rfcomm_dlc_alloc(GFP_KERNEL);
		if (!dlc)
			return -ENOMEM;
	}

	id = rfcomm_dev_add(&req, dlc);
	if (id < 0) {
		rfcomm_dlc_put(dlc);
		return id;
	}

	if (req.flags & (1 << RFCOMM_REUSE_DLC)) {
		/* DLC is now used by device.
		 * Socket must be disconnected */
		sk->sk_state = BT_CLOSED;
	}

	return id;
}

static int rfcomm_release_dev(void __user *arg)
{
	struct rfcomm_dev_req req;
	struct rfcomm_dev *dev;

	if (copy_from_user(&req, arg, sizeof(req)))
		return -EFAULT;

	BT_DBG("dev_id %id flags 0x%x", req.dev_id, req.flags);

	if (!(dev = rfcomm_dev_get(req.dev_id)))
		return -ENODEV;

	if (dev->flags != NOCAP_FLAGS && !capable(CAP_NET_ADMIN)) {
		rfcomm_dev_put(dev);
		return -EPERM;
	}

	if (req.flags & (1 << RFCOMM_HANGUP_NOW))
		rfcomm_dlc_close(dev->dlc, 0);

	rfcomm_dev_del(dev);
	rfcomm_dev_put(dev);
	return 0;
}

static int rfcomm_get_dev_list(void __user *arg)
{
	struct rfcomm_dev_list_req *dl;
	struct rfcomm_dev_info *di;
	struct list_head *p;
	int n = 0, size, err;
	u16 dev_num;

	BT_DBG("");

	if (get_user(dev_num, (u16 __user *) arg))
		return -EFAULT;

	if (!dev_num || dev_num > (PAGE_SIZE * 4) / sizeof(*di))
		return -EINVAL;

	size = sizeof(*dl) + dev_num * sizeof(*di);

	if (!(dl = kmalloc(size, GFP_KERNEL)))
		return -ENOMEM;

	di = dl->dev_info;

	read_lock_bh(&rfcomm_dev_lock);

	list_for_each(p, &rfcomm_dev_list) {
		struct rfcomm_dev *dev = list_entry(p, struct rfcomm_dev, list);
		(di + n)->id      = dev->id;
		(di + n)->flags   = dev->flags;
		(di + n)->state   = dev->dlc->state;
		(di + n)->channel = dev->channel;
		bacpy(&(di + n)->src, &dev->src);
		bacpy(&(di + n)->dst, &dev->dst);
		if (++n >= dev_num)
			break;
	}

	read_unlock_bh(&rfcomm_dev_lock);

	dl->dev_num = n;
	size = sizeof(*dl) + n * sizeof(*di);

	err = copy_to_user(arg, dl, size);
	kfree(dl);

	return err ? -EFAULT : 0;
}

static int rfcomm_get_dev_info(void __user *arg)
{
	struct rfcomm_dev *dev;
	struct rfcomm_dev_info di;
	int err = 0;

	BT_DBG("");

	if (copy_from_user(&di, arg, sizeof(di)))
		return -EFAULT;

	if (!(dev = rfcomm_dev_get(di.id)))
		return -ENODEV;

	di.flags   = dev->flags;
	di.channel = dev->channel;
	di.state   = dev->dlc->state;
	bacpy(&di.src, &dev->src);
	bacpy(&di.dst, &dev->dst);

	if (copy_to_user(arg, &di, sizeof(di)))
		err = -EFAULT;

	rfcomm_dev_put(dev);
	return err;
}

int rfcomm_dev_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
{
	BT_DBG("cmd %d arg %p", cmd, arg);

	switch (cmd) {
	case RFCOMMCREATEDEV:
		return rfcomm_create_dev(sk, arg);

	case RFCOMMRELEASEDEV:
		return rfcomm_release_dev(arg);

	case RFCOMMGETDEVLIST:
		return rfcomm_get_dev_list(arg);

	case RFCOMMGETDEVINFO:
		return rfcomm_get_dev_info(arg);
	}

	return -EINVAL;
}

/* ---- DLC callbacks ---- */
static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb)
{
	struct rfcomm_dev *dev = dlc->owner;
	struct tty_struct *tty;
       
	if (!dev || !(tty = dev->tty)) {
		kfree_skb(skb);
		return;
	}

	BT_DBG("dlc %p tty %p len %d", dlc, tty, skb->len);

	if (test_bit(TTY_DONT_FLIP, &tty->flags)) {
		register int i;
		for (i = 0; i < skb->len; i++) {
			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
				tty_flip_buffer_push(tty);

			tty_insert_flip_char(tty, skb->data[i], 0);
		}
		tty_flip_buffer_push(tty);
	} else
		tty->ldisc.receive_buf(tty, skb->data, NULL, skb->len);

	kfree_skb(skb);
}

static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
{
	struct rfcomm_dev *dev = dlc->owner;
	if (!dev)
		return;
	
	BT_DBG("dlc %p dev %p err %d", dlc, dev, err);

	dev->err = err;
	wake_up_interruptible(&dev->wait);

	if (dlc->state == BT_CLOSED) {
		if (!dev->tty) {
			if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) {
				rfcomm_dev_hold(dev);
				rfcomm_dev_del(dev);

				/* We have to drop DLC lock here, otherwise
				   rfcomm_dev_put() will dead lock if it's
				   the last reference. */
				rfcomm_dlc_unlock(dlc);
				rfcomm_dev_put(dev);
				rfcomm_dlc_lock(dlc);
			}
		} else 
			tty_hangup(dev->tty);
	}
}

static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig)
{
	struct rfcomm_dev *dev = dlc->owner;
	if (!dev)
		return;