xref: /openbmc/linux/net/bluetooth/rfcomm/tty.c (revision 5c816641)
1 /*
2    RFCOMM implementation for Linux Bluetooth stack (BlueZ).
3    Copyright (C) 2002 Maxim Krasnyansky <maxk@qualcomm.com>
4    Copyright (C) 2002 Marcel Holtmann <marcel@holtmann.org>
5 
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License version 2 as
8    published by the Free Software Foundation;
9 
10    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
11    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
12    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
13    IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
14    CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
15    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 
19    ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
20    COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
21    SOFTWARE IS DISCLAIMED.
22 */
23 
24 /*
25  * RFCOMM TTY.
26  */
27 
28 #include <linux/module.h>
29 
30 #include <linux/tty.h>
31 #include <linux/tty_driver.h>
32 #include <linux/tty_flip.h>
33 
34 #include <net/bluetooth/bluetooth.h>
35 #include <net/bluetooth/hci_core.h>
36 #include <net/bluetooth/rfcomm.h>
37 
38 #define RFCOMM_TTY_MAGIC 0x6d02		/* magic number for rfcomm struct */
39 #define RFCOMM_TTY_PORTS RFCOMM_MAX_DEV	/* whole lotta rfcomm devices */
40 #define RFCOMM_TTY_MAJOR 216		/* device node major id of the usb/bluetooth.c driver */
41 #define RFCOMM_TTY_MINOR 0
42 
43 static DEFINE_MUTEX(rfcomm_ioctl_mutex);
44 static struct tty_driver *rfcomm_tty_driver;
45 
46 struct rfcomm_dev {
47 	struct tty_port		port;
48 	struct list_head	list;
49 
50 	char			name[12];
51 	int			id;
52 	unsigned long		flags;
53 	int			err;
54 
55 	unsigned long		status;		/* don't export to userspace */
56 
57 	bdaddr_t		src;
58 	bdaddr_t		dst;
59 	u8			channel;
60 
61 	uint			modem_status;
62 
63 	struct rfcomm_dlc	*dlc;
64 
65 	struct device		*tty_dev;
66 
67 	atomic_t		wmem_alloc;
68 
69 	struct sk_buff_head	pending;
70 };
71 
72 static LIST_HEAD(rfcomm_dev_list);
73 static DEFINE_MUTEX(rfcomm_dev_lock);
74 
75 static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb);
76 static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err);
77 static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig);
78 
79 /* ---- Device functions ---- */
80 
81 static void rfcomm_dev_destruct(struct tty_port *port)
82 {
83 	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
84 	struct rfcomm_dlc *dlc = dev->dlc;
85 
86 	BT_DBG("dev %p dlc %p", dev, dlc);
87 
88 	rfcomm_dlc_lock(dlc);
89 	/* Detach DLC if it's owned by this dev */
90 	if (dlc->owner == dev)
91 		dlc->owner = NULL;
92 	rfcomm_dlc_unlock(dlc);
93 
94 	rfcomm_dlc_put(dlc);
95 
96 	if (dev->tty_dev)
97 		tty_unregister_device(rfcomm_tty_driver, dev->id);
98 
99 	mutex_lock(&rfcomm_dev_lock);
100 	list_del(&dev->list);
101 	mutex_unlock(&rfcomm_dev_lock);
102 
103 	kfree(dev);
104 
105 	/* It's safe to call module_put() here because socket still
106 	   holds reference to this module. */
107 	module_put(THIS_MODULE);
108 }
109 
110 /* device-specific initialization: open the dlc */
111 static int rfcomm_dev_activate(struct tty_port *port, struct tty_struct *tty)
112 {
113 	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
114 	int err;
115 
116 	err = rfcomm_dlc_open(dev->dlc, &dev->src, &dev->dst, dev->channel);
117 	if (err)
118 		set_bit(TTY_IO_ERROR, &tty->flags);
119 	return err;
120 }
121 
122 /* we block the open until the dlc->state becomes BT_CONNECTED */
123 static int rfcomm_dev_carrier_raised(struct tty_port *port)
124 {
125 	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
126 
127 	return (dev->dlc->state == BT_CONNECTED);
128 }
129 
130 /* device-specific cleanup: close the dlc */
131 static void rfcomm_dev_shutdown(struct tty_port *port)
132 {
133 	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
134 
135 	if (dev->tty_dev->parent)
136 		device_move(dev->tty_dev, NULL, DPM_ORDER_DEV_LAST);
137 
138 	/* close the dlc */
139 	rfcomm_dlc_close(dev->dlc, 0);
140 }
141 
142 static const struct tty_port_operations rfcomm_port_ops = {
143 	.destruct = rfcomm_dev_destruct,
144 	.activate = rfcomm_dev_activate,
145 	.shutdown = rfcomm_dev_shutdown,
146 	.carrier_raised = rfcomm_dev_carrier_raised,
147 };
148 
149 static struct rfcomm_dev *__rfcomm_dev_lookup(int id)
150 {
151 	struct rfcomm_dev *dev;
152 
153 	list_for_each_entry(dev, &rfcomm_dev_list, list)
154 		if (dev->id == id)
155 			return dev;
156 
157 	return NULL;
158 }
159 
160 static struct rfcomm_dev *rfcomm_dev_get(int id)
161 {
162 	struct rfcomm_dev *dev;
163 
164 	mutex_lock(&rfcomm_dev_lock);
165 
166 	dev = __rfcomm_dev_lookup(id);
167 
168 	if (dev && !tty_port_get(&dev->port))
169 		dev = NULL;
170 
171 	mutex_unlock(&rfcomm_dev_lock);
172 
173 	return dev;
174 }
175 
176 static void rfcomm_reparent_device(struct rfcomm_dev *dev)
177 {
178 	struct hci_dev *hdev;
179 	struct hci_conn *conn;
180 
181 	hdev = hci_get_route(&dev->dst, &dev->src, BDADDR_BREDR);
182 	if (!hdev)
183 		return;
184 
185 	/* The lookup results are unsafe to access without the
186 	 * hci device lock (FIXME: why is this not documented?)
187 	 */
188 	hci_dev_lock(hdev);
189 	conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, &dev->dst);
190 
191 	/* Just because the acl link is in the hash table is no
192 	 * guarantee the sysfs device has been added ...
193 	 */
194 	if (conn && device_is_registered(&conn->dev))
195 		device_move(dev->tty_dev, &conn->dev, DPM_ORDER_DEV_AFTER_PARENT);
196 
197 	hci_dev_unlock(hdev);
198 	hci_dev_put(hdev);
199 }
200 
201 static ssize_t address_show(struct device *tty_dev,
202 			    struct device_attribute *attr, char *buf)
203 {
204 	struct rfcomm_dev *dev = dev_get_drvdata(tty_dev);
205 	return sprintf(buf, "%pMR\n", &dev->dst);
206 }
207 
208 static ssize_t channel_show(struct device *tty_dev,
209 			    struct device_attribute *attr, char *buf)
210 {
211 	struct rfcomm_dev *dev = dev_get_drvdata(tty_dev);
212 	return sprintf(buf, "%d\n", dev->channel);
213 }
214 
215 static DEVICE_ATTR_RO(address);
216 static DEVICE_ATTR_RO(channel);
217 
218 static struct rfcomm_dev *__rfcomm_dev_add(struct rfcomm_dev_req *req,
219 					   struct rfcomm_dlc *dlc)
220 {
221 	struct rfcomm_dev *dev, *entry;
222 	struct list_head *head = &rfcomm_dev_list;
223 	int err = 0;
224 
225 	dev = kzalloc(sizeof(struct rfcomm_dev), GFP_KERNEL);
226 	if (!dev)
227 		return ERR_PTR(-ENOMEM);
228 
229 	mutex_lock(&rfcomm_dev_lock);
230 
231 	if (req->dev_id < 0) {
232 		dev->id = 0;
233 
234 		list_for_each_entry(entry, &rfcomm_dev_list, list) {
235 			if (entry->id != dev->id)
236 				break;
237 
238 			dev->id++;
239 			head = &entry->list;
240 		}
241 	} else {
242 		dev->id = req->dev_id;
243 
244 		list_for_each_entry(entry, &rfcomm_dev_list, list) {
245 			if (entry->id == dev->id) {
246 				err = -EADDRINUSE;
247 				goto out;
248 			}
249 
250 			if (entry->id > dev->id - 1)
251 				break;
252 
253 			head = &entry->list;
254 		}
255 	}
256 
257 	if ((dev->id < 0) || (dev->id > RFCOMM_MAX_DEV - 1)) {
258 		err = -ENFILE;
259 		goto out;
260 	}
261 
262 	sprintf(dev->name, "rfcomm%d", dev->id);
263 
264 	list_add(&dev->list, head);
265 
266 	bacpy(&dev->src, &req->src);
267 	bacpy(&dev->dst, &req->dst);
268 	dev->channel = req->channel;
269 
270 	dev->flags = req->flags &
271 		((1 << RFCOMM_RELEASE_ONHUP) | (1 << RFCOMM_REUSE_DLC));
272 
273 	tty_port_init(&dev->port);
274 	dev->port.ops = &rfcomm_port_ops;
275 
276 	skb_queue_head_init(&dev->pending);
277 
278 	rfcomm_dlc_lock(dlc);
279 
280 	if (req->flags & (1 << RFCOMM_REUSE_DLC)) {
281 		struct sock *sk = dlc->owner;
282 		struct sk_buff *skb;
283 
284 		BUG_ON(!sk);
285 
286 		rfcomm_dlc_throttle(dlc);
287 
288 		while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
289 			skb_orphan(skb);
290 			skb_queue_tail(&dev->pending, skb);
291 			atomic_sub(skb->len, &sk->sk_rmem_alloc);
292 		}
293 	}
294 
295 	dlc->data_ready   = rfcomm_dev_data_ready;
296 	dlc->state_change = rfcomm_dev_state_change;
297 	dlc->modem_status = rfcomm_dev_modem_status;
298 
299 	dlc->owner = dev;
300 	dev->dlc   = dlc;
301 
302 	rfcomm_dev_modem_status(dlc, dlc->remote_v24_sig);
303 
304 	rfcomm_dlc_unlock(dlc);
305 
306 	/* It's safe to call __module_get() here because socket already
307 	   holds reference to this module. */
308 	__module_get(THIS_MODULE);
309 
310 	mutex_unlock(&rfcomm_dev_lock);
311 	return dev;
312 
313 out:
314 	mutex_unlock(&rfcomm_dev_lock);
315 	kfree(dev);
316 	return ERR_PTR(err);
317 }
318 
319 static int rfcomm_dev_add(struct rfcomm_dev_req *req, struct rfcomm_dlc *dlc)
320 {
321 	struct rfcomm_dev *dev;
322 	struct device *tty;
323 
324 	BT_DBG("id %d channel %d", req->dev_id, req->channel);
325 
326 	dev = __rfcomm_dev_add(req, dlc);
327 	if (IS_ERR(dev)) {
328 		rfcomm_dlc_put(dlc);
329 		return PTR_ERR(dev);
330 	}
331 
332 	tty = tty_port_register_device(&dev->port, rfcomm_tty_driver,
333 			dev->id, NULL);
334 	if (IS_ERR(tty)) {
335 		tty_port_put(&dev->port);
336 		return PTR_ERR(tty);
337 	}
338 
339 	dev->tty_dev = tty;
340 	rfcomm_reparent_device(dev);
341 	dev_set_drvdata(dev->tty_dev, dev);
342 
343 	if (device_create_file(dev->tty_dev, &dev_attr_address) < 0)
344 		BT_ERR("Failed to create address attribute");
345 
346 	if (device_create_file(dev->tty_dev, &dev_attr_channel) < 0)
347 		BT_ERR("Failed to create channel attribute");
348 
349 	return dev->id;
350 }
351 
352 /* ---- Send buffer ---- */
353 static inline unsigned int rfcomm_room(struct rfcomm_dev *dev)
354 {
355 	struct rfcomm_dlc *dlc = dev->dlc;
356 
357 	/* Limit the outstanding number of packets not yet sent to 40 */
358 	int pending = 40 - atomic_read(&dev->wmem_alloc);
359 
360 	return max(0, pending) * dlc->mtu;
361 }
362 
363 static void rfcomm_wfree(struct sk_buff *skb)
364 {
365 	struct rfcomm_dev *dev = (void *) skb->sk;
366 	atomic_dec(&dev->wmem_alloc);
367 	if (test_bit(RFCOMM_TTY_ATTACHED, &dev->flags))
368 		tty_port_tty_wakeup(&dev->port);
369 	tty_port_put(&dev->port);
370 }
371 
372 static void rfcomm_set_owner_w(struct sk_buff *skb, struct rfcomm_dev *dev)
373 {
374 	tty_port_get(&dev->port);
375 	atomic_inc(&dev->wmem_alloc);
376 	skb->sk = (void *) dev;
377 	skb->destructor = rfcomm_wfree;
378 }
379 
380 static struct sk_buff *rfcomm_wmalloc(struct rfcomm_dev *dev, unsigned long size, gfp_t priority)
381 {
382 	struct sk_buff *skb = alloc_skb(size, priority);
383 	if (skb)
384 		rfcomm_set_owner_w(skb, dev);
385 	return skb;
386 }
387 
388 /* ---- Device IOCTLs ---- */
389 
390 #define NOCAP_FLAGS ((1 << RFCOMM_REUSE_DLC) | (1 << RFCOMM_RELEASE_ONHUP))
391 
392 static int __rfcomm_create_dev(struct sock *sk, void __user *arg)
393 {
394 	struct rfcomm_dev_req req;
395 	struct rfcomm_dlc *dlc;
396 	int id;
397 
398 	if (copy_from_user(&req, arg, sizeof(req)))
399 		return -EFAULT;
400 
401 	BT_DBG("sk %p dev_id %d flags 0x%x", sk, req.dev_id, req.flags);
402 
403 	if (req.flags != NOCAP_FLAGS && !capable(CAP_NET_ADMIN))
404 		return -EPERM;
405 
406 	if (req.flags & (1 << RFCOMM_REUSE_DLC)) {
407 		/* Socket must be connected */
408 		if (sk->sk_state != BT_CONNECTED)
409 			return -EBADFD;
410 
411 		dlc = rfcomm_pi(sk)->dlc;
412 		rfcomm_dlc_hold(dlc);
413 	} else {
414 		/* Validate the channel is unused */
415 		dlc = rfcomm_dlc_exists(&req.src, &req.dst, req.channel);
416 		if (IS_ERR(dlc))
417 			return PTR_ERR(dlc);
418 		if (dlc)
419 			return -EBUSY;
420 		dlc = rfcomm_dlc_alloc(GFP_KERNEL);
421 		if (!dlc)
422 			return -ENOMEM;
423 	}
424 
425 	id = rfcomm_dev_add(&req, dlc);
426 	if (id < 0)
427 		return id;
428 
429 	if (req.flags & (1 << RFCOMM_REUSE_DLC)) {
430 		/* DLC is now used by device.
431 		 * Socket must be disconnected */
432 		sk->sk_state = BT_CLOSED;
433 	}
434 
435 	return id;
436 }
437 
438 static int __rfcomm_release_dev(void __user *arg)
439 {
440 	struct rfcomm_dev_req req;
441 	struct rfcomm_dev *dev;
442 	struct tty_struct *tty;
443 
444 	if (copy_from_user(&req, arg, sizeof(req)))
445 		return -EFAULT;
446 
447 	BT_DBG("dev_id %d flags 0x%x", req.dev_id, req.flags);
448 
449 	dev = rfcomm_dev_get(req.dev_id);
450 	if (!dev)
451 		return -ENODEV;
452 
453 	if (dev->flags != NOCAP_FLAGS && !capable(CAP_NET_ADMIN)) {
454 		tty_port_put(&dev->port);
455 		return -EPERM;
456 	}
457 
458 	/* only release once */
459 	if (test_and_set_bit(RFCOMM_DEV_RELEASED, &dev->status)) {
460 		tty_port_put(&dev->port);
461 		return -EALREADY;
462 	}
463 
464 	if (req.flags & (1 << RFCOMM_HANGUP_NOW))
465 		rfcomm_dlc_close(dev->dlc, 0);
466 
467 	/* Shut down TTY synchronously before freeing rfcomm_dev */
468 	tty = tty_port_tty_get(&dev->port);
469 	if (tty) {
470 		tty_vhangup(tty);
471 		tty_kref_put(tty);
472 	}
473 
474 	if (!test_bit(RFCOMM_TTY_OWNED, &dev->status))
475 		tty_port_put(&dev->port);
476 
477 	tty_port_put(&dev->port);
478 	return 0;
479 }
480 
481 static int rfcomm_create_dev(struct sock *sk, void __user *arg)
482 {
483 	int ret;
484 
485 	mutex_lock(&rfcomm_ioctl_mutex);
486 	ret = __rfcomm_create_dev(sk, arg);
487 	mutex_unlock(&rfcomm_ioctl_mutex);
488 
489 	return ret;
490 }
491 
492 static int rfcomm_release_dev(void __user *arg)
493 {
494 	int ret;
495 
496 	mutex_lock(&rfcomm_ioctl_mutex);
497 	ret = __rfcomm_release_dev(arg);
498 	mutex_unlock(&rfcomm_ioctl_mutex);
499 
500 	return ret;
501 }
502 
503 static int rfcomm_get_dev_list(void __user *arg)
504 {
505 	struct rfcomm_dev *dev;
506 	struct rfcomm_dev_list_req *dl;
507 	struct rfcomm_dev_info *di;
508 	int n = 0, size, err;
509 	u16 dev_num;
510 
511 	BT_DBG("");
512 
513 	if (get_user(dev_num, (u16 __user *) arg))
514 		return -EFAULT;
515 
516 	if (!dev_num || dev_num > (PAGE_SIZE * 4) / sizeof(*di))
517 		return -EINVAL;
518 
519 	size = sizeof(*dl) + dev_num * sizeof(*di);
520 
521 	dl = kzalloc(size, GFP_KERNEL);
522 	if (!dl)
523 		return -ENOMEM;
524 
525 	di = dl->dev_info;
526 
527 	mutex_lock(&rfcomm_dev_lock);
528 
529 	list_for_each_entry(dev, &rfcomm_dev_list, list) {
530 		if (!tty_port_get(&dev->port))
531 			continue;
532 		(di + n)->id      = dev->id;
533 		(di + n)->flags   = dev->flags;
534 		(di + n)->state   = dev->dlc->state;
535 		(di + n)->channel = dev->channel;
536 		bacpy(&(di + n)->src, &dev->src);
537 		bacpy(&(di + n)->dst, &dev->dst);
538 		tty_port_put(&dev->port);
539 		if (++n >= dev_num)
540 			break;
541 	}
542 
543 	mutex_unlock(&rfcomm_dev_lock);
544 
545 	dl->dev_num = n;
546 	size = sizeof(*dl) + n * sizeof(*di);
547 
548 	err = copy_to_user(arg, dl, size);
549 	kfree(dl);
550 
551 	return err ? -EFAULT : 0;
552 }
553 
554 static int rfcomm_get_dev_info(void __user *arg)
555 {
556 	struct rfcomm_dev *dev;
557 	struct rfcomm_dev_info di;
558 	int err = 0;
559 
560 	BT_DBG("");
561 
562 	if (copy_from_user(&di, arg, sizeof(di)))
563 		return -EFAULT;
564 
565 	dev = rfcomm_dev_get(di.id);
566 	if (!dev)
567 		return -ENODEV;
568 
569 	di.flags   = dev->flags;
570 	di.channel = dev->channel;
571 	di.state   = dev->dlc->state;
572 	bacpy(&di.src, &dev->src);
573 	bacpy(&di.dst, &dev->dst);
574 
575 	if (copy_to_user(arg, &di, sizeof(di)))
576 		err = -EFAULT;
577 
578 	tty_port_put(&dev->port);
579 	return err;
580 }
581 
582 int rfcomm_dev_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
583 {
584 	BT_DBG("cmd %d arg %p", cmd, arg);
585 
586 	switch (cmd) {
587 	case RFCOMMCREATEDEV:
588 		return rfcomm_create_dev(sk, arg);
589 
590 	case RFCOMMRELEASEDEV:
591 		return rfcomm_release_dev(arg);
592 
593 	case RFCOMMGETDEVLIST:
594 		return rfcomm_get_dev_list(arg);
595 
596 	case RFCOMMGETDEVINFO:
597 		return rfcomm_get_dev_info(arg);
598 	}
599 
600 	return -EINVAL;
601 }
602 
603 /* ---- DLC callbacks ---- */
604 static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb)
605 {
606 	struct rfcomm_dev *dev = dlc->owner;
607 
608 	if (!dev) {
609 		kfree_skb(skb);
610 		return;
611 	}
612 
613 	if (!skb_queue_empty(&dev->pending)) {
614 		skb_queue_tail(&dev->pending, skb);
615 		return;
616 	}
617 
618 	BT_DBG("dlc %p len %d", dlc, skb->len);
619 
620 	tty_insert_flip_string(&dev->port, skb->data, skb->len);
621 	tty_flip_buffer_push(&dev->port);
622 
623 	kfree_skb(skb);
624 }
625 
626 static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
627 {
628 	struct rfcomm_dev *dev = dlc->owner;
629 	if (!dev)
630 		return;
631 
632 	BT_DBG("dlc %p dev %p err %d", dlc, dev, err);
633 
634 	dev->err = err;
635 	if (dlc->state == BT_CONNECTED) {
636 		rfcomm_reparent_device(dev);
637 
638 		wake_up_interruptible(&dev->port.open_wait);
639 	} else if (dlc->state == BT_CLOSED)
640 		tty_port_tty_hangup(&dev->port, false);
641 }
642 
643 static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig)
644 {
645 	struct rfcomm_dev *dev = dlc->owner;
646 	if (!dev)
647 		return;
648 
649 	BT_DBG("dlc %p dev %p v24_sig 0x%02x", dlc, dev, v24_sig);
650 
651 	if ((dev->modem_status & TIOCM_CD) && !(v24_sig & RFCOMM_V24_DV))
652 		tty_port_tty_hangup(&dev->port, true);
653 
654 	dev->modem_status =
655 		((v24_sig & RFCOMM_V24_RTC) ? (TIOCM_DSR | TIOCM_DTR) : 0) |
656 		((v24_sig & RFCOMM_V24_RTR) ? (TIOCM_RTS | TIOCM_CTS) : 0) |
657 		((v24_sig & RFCOMM_V24_IC)  ? TIOCM_RI : 0) |
658 		((v24_sig & RFCOMM_V24_DV)  ? TIOCM_CD : 0);
659 }
660 
661 /* ---- TTY functions ---- */
662 static void rfcomm_tty_copy_pending(struct rfcomm_dev *dev)
663 {
664 	struct sk_buff *skb;
665 	int inserted = 0;
666 
667 	BT_DBG("dev %p", dev);
668 
669 	rfcomm_dlc_lock(dev->dlc);
670 
671 	while ((skb = skb_dequeue(&dev->pending))) {
672 		inserted += tty_insert_flip_string(&dev->port, skb->data,
673 				skb->len);
674 		kfree_skb(skb);
675 	}
676 
677 	rfcomm_dlc_unlock(dev->dlc);
678 
679 	if (inserted > 0)
680 		tty_flip_buffer_push(&dev->port);
681 }
682 
683 /* do the reverse of install, clearing the tty fields and releasing the
684  * reference to tty_port
685  */
686 static void rfcomm_tty_cleanup(struct tty_struct *tty)
687 {
688 	struct rfcomm_dev *dev = tty->driver_data;
689 
690 	clear_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
691 
692 	rfcomm_dlc_lock(dev->dlc);
693 	tty->driver_data = NULL;
694 	rfcomm_dlc_unlock(dev->dlc);
695 
696 	/*
697 	 * purge the dlc->tx_queue to avoid circular dependencies
698 	 * between dev and dlc
699 	 */
700 	skb_queue_purge(&dev->dlc->tx_queue);
701 
702 	tty_port_put(&dev->port);
703 }
704 
705 /* we acquire the tty_port reference since it's here the tty is first used
706  * by setting the termios. We also populate the driver_data field and install
707  * the tty port
708  */
709 static int rfcomm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
710 {
711 	struct rfcomm_dev *dev;
712 	struct rfcomm_dlc *dlc;
713 	int err;
714 
715 	dev = rfcomm_dev_get(tty->index);
716 	if (!dev)
717 		return -ENODEV;
718 
719 	dlc = dev->dlc;
720 
721 	/* Attach TTY and open DLC */
722 	rfcomm_dlc_lock(dlc);
723 	tty->driver_data = dev;
724 	rfcomm_dlc_unlock(dlc);
725 	set_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
726 
727 	/* install the tty_port */
728 	err = tty_port_install(&dev->port, driver, tty);
729 	if (err) {
730 		rfcomm_tty_cleanup(tty);
731 		return err;
732 	}
733 
734 	/* take over the tty_port reference if the port was created with the
735 	 * flag RFCOMM_RELEASE_ONHUP. This will force the release of the port
736 	 * when the last process closes the tty. The behaviour is expected by
737 	 * userspace.
738 	 */
739 	if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) {
740 		set_bit(RFCOMM_TTY_OWNED, &dev->status);
741 		tty_port_put(&dev->port);
742 	}
743 
744 	return 0;
745 }
746 
747 static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
748 {
749 	struct rfcomm_dev *dev = tty->driver_data;
750 	int err;
751 
752 	BT_DBG("tty %p id %d", tty, tty->index);
753 
754 	BT_DBG("dev %p dst %pMR channel %d opened %d", dev, &dev->dst,
755 	       dev->channel, dev->port.count);
756 
757 	err = tty_port_open(&dev->port, tty, filp);
758 	if (err)
759 		return err;
760 
761 	/*
762 	 * FIXME: rfcomm should use proper flow control for
763 	 * received data. This hack will be unnecessary and can
764 	 * be removed when that's implemented
765 	 */
766 	rfcomm_tty_copy_pending(dev);
767 
768 	rfcomm_dlc_unthrottle(dev->dlc);
769 
770 	return 0;
771 }
772 
773 static void rfcomm_tty_close(struct tty_struct *tty, struct file *filp)
774 {
775 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
776 
777 	BT_DBG("tty %p dev %p dlc %p opened %d", tty, dev, dev->dlc,
778 						dev->port.count);
779 
780 	tty_port_close(&dev->port, tty, filp);
781 }
782 
783 static int rfcomm_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
784 {
785 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
786 	struct rfcomm_dlc *dlc = dev->dlc;
787 	struct sk_buff *skb;
788 	int sent = 0, size;
789 
790 	BT_DBG("tty %p count %d", tty, count);
791 
792 	while (count) {
793 		size = min_t(uint, count, dlc->mtu);
794 
795 		skb = rfcomm_wmalloc(dev, size + RFCOMM_SKB_RESERVE, GFP_ATOMIC);
796 		if (!skb)
797 			break;
798 
799 		skb_reserve(skb, RFCOMM_SKB_HEAD_RESERVE);
800 
801 		skb_put_data(skb, buf + sent, size);
802 
803 		rfcomm_dlc_send_noerror(dlc, skb);
804 
805 		sent  += size;
806 		count -= size;
807 	}
808 
809 	return sent;
810 }
811 
812 static unsigned int rfcomm_tty_write_room(struct tty_struct *tty)
813 {
814 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
815 	int room = 0;
816 
817 	if (dev && dev->dlc)
818 		room = rfcomm_room(dev);
819 
820 	BT_DBG("tty %p room %d", tty, room);
821 
822 	return room;
823 }
824 
825 static int rfcomm_tty_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
826 {
827 	BT_DBG("tty %p cmd 0x%02x", tty, cmd);
828 
829 	switch (cmd) {
830 	case TCGETS:
831 		BT_DBG("TCGETS is not supported");
832 		return -ENOIOCTLCMD;
833 
834 	case TCSETS:
835 		BT_DBG("TCSETS is not supported");
836 		return -ENOIOCTLCMD;
837 
838 	case TIOCMIWAIT:
839 		BT_DBG("TIOCMIWAIT");
840 		break;
841 
842 	case TIOCSERGETLSR:
843 		BT_ERR("TIOCSERGETLSR is not supported");
844 		return -ENOIOCTLCMD;
845 
846 	case TIOCSERCONFIG:
847 		BT_ERR("TIOCSERCONFIG is not supported");
848 		return -ENOIOCTLCMD;
849 
850 	default:
851 		return -ENOIOCTLCMD;	/* ioctls which we must ignore */
852 
853 	}
854 
855 	return -ENOIOCTLCMD;
856 }
857 
858 static void rfcomm_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
859 {
860 	struct ktermios *new = &tty->termios;
861 	int old_baud_rate = tty_termios_baud_rate(old);
862 	int new_baud_rate = tty_termios_baud_rate(new);
863 
864 	u8 baud, data_bits, stop_bits, parity, x_on, x_off;
865 	u16 changes = 0;
866 
867 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
868 
869 	BT_DBG("tty %p termios %p", tty, old);
870 
871 	if (!dev || !dev->dlc || !dev->dlc->session)
872 		return;
873 
874 	/* Handle turning off CRTSCTS */
875 	if ((old->c_cflag & CRTSCTS) && !(new->c_cflag & CRTSCTS))
876 		BT_DBG("Turning off CRTSCTS unsupported");
877 
878 	/* Parity on/off and when on, odd/even */
879 	if (((old->c_cflag & PARENB) != (new->c_cflag & PARENB)) ||
880 			((old->c_cflag & PARODD) != (new->c_cflag & PARODD))) {
881 		changes |= RFCOMM_RPN_PM_PARITY;
882 		BT_DBG("Parity change detected.");
883 	}
884 
885 	/* Mark and space parity are not supported! */
886 	if (new->c_cflag & PARENB) {
887 		if (new->c_cflag & PARODD) {
888 			BT_DBG("Parity is ODD");
889 			parity = RFCOMM_RPN_PARITY_ODD;
890 		} else {
891 			BT_DBG("Parity is EVEN");
892 			parity = RFCOMM_RPN_PARITY_EVEN;
893 		}
894 	} else {
895 		BT_DBG("Parity is OFF");
896 		parity = RFCOMM_RPN_PARITY_NONE;
897 	}
898 
899 	/* Setting the x_on / x_off characters */
900 	if (old->c_cc[VSTOP] != new->c_cc[VSTOP]) {
901 		BT_DBG("XOFF custom");
902 		x_on = new->c_cc[VSTOP];
903 		changes |= RFCOMM_RPN_PM_XON;
904 	} else {
905 		BT_DBG("XOFF default");
906 		x_on = RFCOMM_RPN_XON_CHAR;
907 	}
908 
909 	if (old->c_cc[VSTART] != new->c_cc[VSTART]) {
910 		BT_DBG("XON custom");
911 		x_off = new->c_cc[VSTART];
912 		changes |= RFCOMM_RPN_PM_XOFF;
913 	} else {
914 		BT_DBG("XON default");
915 		x_off = RFCOMM_RPN_XOFF_CHAR;
916 	}
917 
918 	/* Handle setting of stop bits */
919 	if ((old->c_cflag & CSTOPB) != (new->c_cflag & CSTOPB))
920 		changes |= RFCOMM_RPN_PM_STOP;
921 
922 	/* POSIX does not support 1.5 stop bits and RFCOMM does not
923 	 * support 2 stop bits. So a request for 2 stop bits gets
924 	 * translated to 1.5 stop bits */
925 	if (new->c_cflag & CSTOPB)
926 		stop_bits = RFCOMM_RPN_STOP_15;
927 	else
928 		stop_bits = RFCOMM_RPN_STOP_1;
929 
930 	/* Handle number of data bits [5-8] */
931 	if ((old->c_cflag & CSIZE) != (new->c_cflag & CSIZE))
932 		changes |= RFCOMM_RPN_PM_DATA;
933 
934 	switch (new->c_cflag & CSIZE) {
935 	case CS5:
936 		data_bits = RFCOMM_RPN_DATA_5;
937 		break;
938 	case CS6:
939 		data_bits = RFCOMM_RPN_DATA_6;
940 		break;
941 	case CS7:
942 		data_bits = RFCOMM_RPN_DATA_7;
943 		break;
944 	case CS8:
945 		data_bits = RFCOMM_RPN_DATA_8;
946 		break;
947 	default:
948 		data_bits = RFCOMM_RPN_DATA_8;
949 		break;
950 	}
951 
952 	/* Handle baudrate settings */
953 	if (old_baud_rate != new_baud_rate)
954 		changes |= RFCOMM_RPN_PM_BITRATE;
955 
956 	switch (new_baud_rate) {
957 	case 2400:
958 		baud = RFCOMM_RPN_BR_2400;
959 		break;
960 	case 4800:
961 		baud = RFCOMM_RPN_BR_4800;
962 		break;
963 	case 7200:
964 		baud = RFCOMM_RPN_BR_7200;
965 		break;
966 	case 9600:
967 		baud = RFCOMM_RPN_BR_9600;
968 		break;
969 	case 19200:
970 		baud = RFCOMM_RPN_BR_19200;
971 		break;
972 	case 38400:
973 		baud = RFCOMM_RPN_BR_38400;
974 		break;
975 	case 57600:
976 		baud = RFCOMM_RPN_BR_57600;
977 		break;
978 	case 115200:
979 		baud = RFCOMM_RPN_BR_115200;
980 		break;
981 	case 230400:
982 		baud = RFCOMM_RPN_BR_230400;
983 		break;
984 	default:
985 		/* 9600 is standard accordinag to the RFCOMM specification */
986 		baud = RFCOMM_RPN_BR_9600;
987 		break;
988 
989 	}
990 
991 	if (changes)
992 		rfcomm_send_rpn(dev->dlc->session, 1, dev->dlc->dlci, baud,
993 				data_bits, stop_bits, parity,
994 				RFCOMM_RPN_FLOW_NONE, x_on, x_off, changes);
995 }
996 
997 static void rfcomm_tty_throttle(struct tty_struct *tty)
998 {
999 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
1000 
1001 	BT_DBG("tty %p dev %p", tty, dev);
1002 
1003 	rfcomm_dlc_throttle(dev->dlc);
1004 }
1005 
1006 static void rfcomm_tty_unthrottle(struct tty_struct *tty)
1007 {
1008 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
1009 
1010 	BT_DBG("tty %p dev %p", tty, dev);
1011 
1012 	rfcomm_dlc_unthrottle(dev->dlc);
1013 }
1014 
1015 static unsigned int rfcomm_tty_chars_in_buffer(struct tty_struct *tty)
1016 {
1017 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
1018 
1019 	BT_DBG("tty %p dev %p", tty, dev);
1020 
1021 	if (!dev || !dev->dlc)
1022 		return 0;
1023 
1024 	if (!skb_queue_empty(&dev->dlc->tx_queue))
1025 		return dev->dlc->mtu;
1026 
1027 	return 0;
1028 }
1029 
1030 static void rfcomm_tty_flush_buffer(struct tty_struct *tty)
1031 {
1032 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
1033 
1034 	BT_DBG("tty %p dev %p", tty, dev);
1035 
1036 	if (!dev || !dev->dlc)
1037 		return;
1038 
1039 	skb_queue_purge(&dev->dlc->tx_queue);
1040 	tty_wakeup(tty);
1041 }
1042 
1043 static void rfcomm_tty_send_xchar(struct tty_struct *tty, char ch)
1044 {
1045 	BT_DBG("tty %p ch %c", tty, ch);
1046 }
1047 
1048 static void rfcomm_tty_wait_until_sent(struct tty_struct *tty, int timeout)
1049 {
1050 	BT_DBG("tty %p timeout %d", tty, timeout);
1051 }
1052 
1053 static void rfcomm_tty_hangup(struct tty_struct *tty)
1054 {
1055 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
1056 
1057 	BT_DBG("tty %p dev %p", tty, dev);
1058 
1059 	tty_port_hangup(&dev->port);
1060 }
1061 
1062 static int rfcomm_tty_tiocmget(struct tty_struct *tty)
1063 {
1064 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
1065 
1066 	BT_DBG("tty %p dev %p", tty, dev);
1067 
1068 	return dev->modem_status;
1069 }
1070 
1071 static int rfcomm_tty_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1072 {
1073 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
1074 	struct rfcomm_dlc *dlc = dev->dlc;
1075 	u8 v24_sig;
1076 
1077 	BT_DBG("tty %p dev %p set 0x%02x clear 0x%02x", tty, dev, set, clear);
1078 
1079 	rfcomm_dlc_get_modem_status(dlc, &v24_sig);
1080 
1081 	if (set & TIOCM_DSR || set & TIOCM_DTR)
1082 		v24_sig |= RFCOMM_V24_RTC;
1083 	if (set & TIOCM_RTS || set & TIOCM_CTS)
1084 		v24_sig |= RFCOMM_V24_RTR;
1085 	if (set & TIOCM_RI)
1086 		v24_sig |= RFCOMM_V24_IC;
1087 	if (set & TIOCM_CD)
1088 		v24_sig |= RFCOMM_V24_DV;
1089 
1090 	if (clear & TIOCM_DSR || clear & TIOCM_DTR)
1091 		v24_sig &= ~RFCOMM_V24_RTC;
1092 	if (clear & TIOCM_RTS || clear & TIOCM_CTS)
1093 		v24_sig &= ~RFCOMM_V24_RTR;
1094 	if (clear & TIOCM_RI)
1095 		v24_sig &= ~RFCOMM_V24_IC;
1096 	if (clear & TIOCM_CD)
1097 		v24_sig &= ~RFCOMM_V24_DV;
1098 
1099 	rfcomm_dlc_set_modem_status(dlc, v24_sig);
1100 
1101 	return 0;
1102 }
1103 
1104 /* ---- TTY structure ---- */
1105 
1106 static const struct tty_operations rfcomm_ops = {
1107 	.open			= rfcomm_tty_open,
1108 	.close			= rfcomm_tty_close,
1109 	.write			= rfcomm_tty_write,
1110 	.write_room		= rfcomm_tty_write_room,
1111 	.chars_in_buffer	= rfcomm_tty_chars_in_buffer,
1112 	.flush_buffer		= rfcomm_tty_flush_buffer,
1113 	.ioctl			= rfcomm_tty_ioctl,
1114 	.throttle		= rfcomm_tty_throttle,
1115 	.unthrottle		= rfcomm_tty_unthrottle,
1116 	.set_termios		= rfcomm_tty_set_termios,
1117 	.send_xchar		= rfcomm_tty_send_xchar,
1118 	.hangup			= rfcomm_tty_hangup,
1119 	.wait_until_sent	= rfcomm_tty_wait_until_sent,
1120 	.tiocmget		= rfcomm_tty_tiocmget,
1121 	.tiocmset		= rfcomm_tty_tiocmset,
1122 	.install                = rfcomm_tty_install,
1123 	.cleanup                = rfcomm_tty_cleanup,
1124 };
1125 
1126 int __init rfcomm_init_ttys(void)
1127 {
1128 	int error;
1129 
1130 	rfcomm_tty_driver = tty_alloc_driver(RFCOMM_TTY_PORTS,
1131 			TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV);
1132 	if (IS_ERR(rfcomm_tty_driver))
1133 		return PTR_ERR(rfcomm_tty_driver);
1134 
1135 	rfcomm_tty_driver->driver_name	= "rfcomm";
1136 	rfcomm_tty_driver->name		= "rfcomm";
1137 	rfcomm_tty_driver->major	= RFCOMM_TTY_MAJOR;
1138 	rfcomm_tty_driver->minor_start	= RFCOMM_TTY_MINOR;
1139 	rfcomm_tty_driver->type		= TTY_DRIVER_TYPE_SERIAL;
1140 	rfcomm_tty_driver->subtype	= SERIAL_TYPE_NORMAL;
1141 	rfcomm_tty_driver->init_termios	= tty_std_termios;
1142 	rfcomm_tty_driver->init_termios.c_cflag	= B9600 | CS8 | CREAD | HUPCL;
1143 	rfcomm_tty_driver->init_termios.c_lflag &= ~ICANON;
1144 	tty_set_operations(rfcomm_tty_driver, &rfcomm_ops);
1145 
1146 	error = tty_register_driver(rfcomm_tty_driver);
1147 	if (error) {
1148 		BT_ERR("Can't register RFCOMM TTY driver");
1149 		tty_driver_kref_put(rfcomm_tty_driver);
1150 		return error;
1151 	}
1152 
1153 	BT_INFO("RFCOMM TTY layer initialized");
1154 
1155 	return 0;
1156 }
1157 
1158 void rfcomm_cleanup_ttys(void)
1159 {
1160 	tty_unregister_driver(rfcomm_tty_driver);
1161 	tty_driver_kref_put(rfcomm_tty_driver);
1162 }
1163