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1/*
2 * slcan.c - serial line CAN interface driver (using tty line discipline)
3 *
4 * This file is derived from linux/drivers/net/slip/slip.c
5 *
6 * slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk>
7 * Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
8 * slcan.c Author : Oliver Hartkopp <socketcan@hartkopp.net>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation; either version 2 of the License, or (at your
13 * option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License along
21 * with this program; if not, see http://www.gnu.org/licenses/gpl.html
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
29 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
33 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
34 * DAMAGE.
35 *
36 */
37
38#include <linux/module.h>
39#include <linux/moduleparam.h>
40
41#include <linux/uaccess.h>
42#include <linux/bitops.h>
43#include <linux/string.h>
44#include <linux/tty.h>
45#include <linux/errno.h>
46#include <linux/netdevice.h>
47#include <linux/skbuff.h>
48#include <linux/rtnetlink.h>
49#include <linux/if_arp.h>
50#include <linux/if_ether.h>
51#include <linux/sched.h>
52#include <linux/delay.h>
53#include <linux/init.h>
54#include <linux/kernel.h>
55#include <linux/can.h>
56#include <linux/can/skb.h>
57
58static __initconst const char banner[] =
59 KERN_INFO "slcan: serial line CAN interface driver\n";
60
61MODULE_ALIAS_LDISC(N_SLCAN);
62MODULE_DESCRIPTION("serial line CAN interface");
63MODULE_LICENSE("GPL");
64MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
65
66#define SLCAN_MAGIC 0x53CA
67
68static int maxdev = 10; /* MAX number of SLCAN channels;
69 This can be overridden with
70 insmod slcan.ko maxdev=nnn */
71module_param(maxdev, int, 0);
72MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
73
74/* maximum rx buffer len: extended CAN frame with timestamp */
75#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
76
77#define SLC_CMD_LEN 1
78#define SLC_SFF_ID_LEN 3
79#define SLC_EFF_ID_LEN 8
80
81struct slcan {
82 int magic;
83
84 /* Various fields. */
85 struct tty_struct *tty; /* ptr to TTY structure */
86 struct net_device *dev; /* easy for intr handling */
87 spinlock_t lock;
88
89 /* These are pointers to the malloc()ed frame buffers. */
90 unsigned char rbuff[SLC_MTU]; /* receiver buffer */
91 int rcount; /* received chars counter */
92 unsigned char xbuff[SLC_MTU]; /* transmitter buffer */
93 unsigned char *xhead; /* pointer to next XMIT byte */
94 int xleft; /* bytes left in XMIT queue */
95
96 unsigned long flags; /* Flag values/ mode etc */
97#define SLF_INUSE 0 /* Channel in use */
98#define SLF_ERROR 1 /* Parity, etc. error */
99};
100
101static struct net_device **slcan_devs;
102
103 /************************************************************************
104 * SLCAN ENCAPSULATION FORMAT *
105 ************************************************************************/
106
107/*
108 * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
109 * frame format) a data length code (can_dlc) which can be from 0 to 8
110 * and up to <can_dlc> data bytes as payload.
111 * Additionally a CAN frame may become a remote transmission frame if the
112 * RTR-bit is set. This causes another ECU to send a CAN frame with the
113 * given can_id.
114 *
115 * The SLCAN ASCII representation of these different frame types is:
116 * <type> <id> <dlc> <data>*
117 *
118 * Extended frames (29 bit) are defined by capital characters in the type.
119 * RTR frames are defined as 'r' types - normal frames have 't' type:
120 * t => 11 bit data frame
121 * r => 11 bit RTR frame
122 * T => 29 bit data frame
123 * R => 29 bit RTR frame
124 *
125 * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
126 * The <dlc> is a one byte ASCII number ('0' - '8')
127 * The <data> section has at much ASCII Hex bytes as defined by the <dlc>
128 *
129 * Examples:
130 *
131 * t1230 : can_id 0x123, can_dlc 0, no data
132 * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33
133 * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55
134 * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request
135 *
136 */
137
138 /************************************************************************
139 * STANDARD SLCAN DECAPSULATION *
140 ************************************************************************/
141
142/* Send one completely decapsulated can_frame to the network layer */
143static void slc_bump(struct slcan *sl)
144{
145 struct sk_buff *skb;
146 struct can_frame cf;
147 int i, tmp;
148 u32 tmpid;
149 char *cmd = sl->rbuff;
150
151 cf.can_id = 0;
152
153 switch (*cmd) {
154 case 'r':
155 cf.can_id = CAN_RTR_FLAG;
156 /* fallthrough */
157 case 't':
158 /* store dlc ASCII value and terminate SFF CAN ID string */
159 cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN];
160 sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN] = 0;
161 /* point to payload data behind the dlc */
162 cmd += SLC_CMD_LEN + SLC_SFF_ID_LEN + 1;
163 break;
164 case 'R':
165 cf.can_id = CAN_RTR_FLAG;
166 /* fallthrough */
167 case 'T':
168 cf.can_id |= CAN_EFF_FLAG;
169 /* store dlc ASCII value and terminate EFF CAN ID string */
170 cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN];
171 sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN] = 0;
172 /* point to payload data behind the dlc */
173 cmd += SLC_CMD_LEN + SLC_EFF_ID_LEN + 1;
174 break;
175 default:
176 return;
177 }
178
179 if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid))
180 return;
181
182 cf.can_id |= tmpid;
183
184 /* get can_dlc from sanitized ASCII value */
185 if (cf.can_dlc >= '0' && cf.can_dlc < '9')
186 cf.can_dlc -= '0';
187 else
188 return;
189
190 *(u64 *) (&cf.data) = 0; /* clear payload */
191
192 /* RTR frames may have a dlc > 0 but they never have any data bytes */
193 if (!(cf.can_id & CAN_RTR_FLAG)) {
194 for (i = 0; i < cf.can_dlc; i++) {
195 tmp = hex_to_bin(*cmd++);
196 if (tmp < 0)
197 return;
198 cf.data[i] = (tmp << 4);
199 tmp = hex_to_bin(*cmd++);
200 if (tmp < 0)
201 return;
202 cf.data[i] |= tmp;
203 }
204 }
205
206 skb = dev_alloc_skb(sizeof(struct can_frame) +
207 sizeof(struct can_skb_priv));
208 if (!skb)
209 return;
210
211 skb->dev = sl->dev;
212 skb->protocol = htons(ETH_P_CAN);
213 skb->pkt_type = PACKET_BROADCAST;
214 skb->ip_summed = CHECKSUM_UNNECESSARY;
215
216 can_skb_reserve(skb);
217 can_skb_prv(skb)->ifindex = sl->dev->ifindex;
218
219 memcpy(skb_put(skb, sizeof(struct can_frame)),
220 &cf, sizeof(struct can_frame));
221 netif_rx_ni(skb);
222
223 sl->dev->stats.rx_packets++;
224 sl->dev->stats.rx_bytes += cf.can_dlc;
225}
226
227/* parse tty input stream */
228static void slcan_unesc(struct slcan *sl, unsigned char s)
229{
230 if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
231 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
232 (sl->rcount > 4)) {
233 slc_bump(sl);
234 }
235 sl->rcount = 0;
236 } else {
237 if (!test_bit(SLF_ERROR, &sl->flags)) {
238 if (sl->rcount < SLC_MTU) {
239 sl->rbuff[sl->rcount++] = s;
240 return;
241 } else {
242 sl->dev->stats.rx_over_errors++;
243 set_bit(SLF_ERROR, &sl->flags);
244 }
245 }
246 }
247}
248
249 /************************************************************************
250 * STANDARD SLCAN ENCAPSULATION *
251 ************************************************************************/
252
253/* Encapsulate one can_frame and stuff into a TTY queue. */
254static void slc_encaps(struct slcan *sl, struct can_frame *cf)
255{
256 int actual, i;
257 unsigned char *pos;
258 unsigned char *endpos;
259 canid_t id = cf->can_id;
260
261 pos = sl->xbuff;
262
263 if (cf->can_id & CAN_RTR_FLAG)
264 *pos = 'R'; /* becomes 'r' in standard frame format (SFF) */
265 else
266 *pos = 'T'; /* becomes 't' in standard frame format (SSF) */
267
268 /* determine number of chars for the CAN-identifier */
269 if (cf->can_id & CAN_EFF_FLAG) {
270 id &= CAN_EFF_MASK;
271 endpos = pos + SLC_EFF_ID_LEN;
272 } else {
273 *pos |= 0x20; /* convert R/T to lower case for SFF */
274 id &= CAN_SFF_MASK;
275 endpos = pos + SLC_SFF_ID_LEN;
276 }
277
278 /* build 3 (SFF) or 8 (EFF) digit CAN identifier */
279 pos++;
280 while (endpos >= pos) {
281 *endpos-- = hex_asc_upper[id & 0xf];
282 id >>= 4;
283 }
284
285 pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN;
286
287 *pos++ = cf->can_dlc + '0';
288
289 /* RTR frames may have a dlc > 0 but they never have any data bytes */
290 if (!(cf->can_id & CAN_RTR_FLAG)) {
291 for (i = 0; i < cf->can_dlc; i++)
292 pos = hex_byte_pack_upper(pos, cf->data[i]);
293 }
294
295 *pos++ = '\r';
296
297 /* Order of next two lines is *very* important.
298 * When we are sending a little amount of data,
299 * the transfer may be completed inside the ops->write()
300 * routine, because it's running with interrupts enabled.
301 * In this case we *never* got WRITE_WAKEUP event,
302 * if we did not request it before write operation.
303 * 14 Oct 1994 Dmitry Gorodchanin.
304 */
305 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
306 actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff);
307 sl->xleft = (pos - sl->xbuff) - actual;
308 sl->xhead = sl->xbuff + actual;
309 sl->dev->stats.tx_bytes += cf->can_dlc;
310}
311
312/*
313 * Called by the driver when there's room for more data. If we have
314 * more packets to send, we send them here.
315 */
316static void slcan_write_wakeup(struct tty_struct *tty)
317{
318 int actual;
319 struct slcan *sl = (struct slcan *) tty->disc_data;
320
321 /* First make sure we're connected. */
322 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
323 return;
324
325 spin_lock_bh(&sl->lock);
326 if (sl->xleft <= 0) {
327 /* Now serial buffer is almost free & we can start
328 * transmission of another packet */
329 sl->dev->stats.tx_packets++;
330 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
331 spin_unlock_bh(&sl->lock);
332 netif_wake_queue(sl->dev);
333 return;
334 }
335
336 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
337 sl->xleft -= actual;
338 sl->xhead += actual;
339 spin_unlock_bh(&sl->lock);
340}
341
342/* Send a can_frame to a TTY queue. */
343static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
344{
345 struct slcan *sl = netdev_priv(dev);
346
347 if (skb->len != sizeof(struct can_frame))
348 goto out;
349
350 spin_lock(&sl->lock);
351 if (!netif_running(dev)) {
352 spin_unlock(&sl->lock);
353 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
354 goto out;
355 }
356 if (sl->tty == NULL) {
357 spin_unlock(&sl->lock);
358 goto out;
359 }
360
361 netif_stop_queue(sl->dev);
362 slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
363 spin_unlock(&sl->lock);
364
365out:
366 kfree_skb(skb);
367 return NETDEV_TX_OK;
368}
369
370
371/******************************************
372 * Routines looking at netdevice side.
373 ******************************************/
374
375/* Netdevice UP -> DOWN routine */
376static int slc_close(struct net_device *dev)
377{
378 struct slcan *sl = netdev_priv(dev);
379
380 spin_lock_bh(&sl->lock);
381 if (sl->tty) {
382 /* TTY discipline is running. */
383 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
384 }
385 netif_stop_queue(dev);
386 sl->rcount = 0;
387 sl->xleft = 0;
388 spin_unlock_bh(&sl->lock);
389
390 return 0;
391}
392
393/* Netdevice DOWN -> UP routine */
394static int slc_open(struct net_device *dev)
395{
396 struct slcan *sl = netdev_priv(dev);
397
398 if (sl->tty == NULL)
399 return -ENODEV;
400
401 sl->flags &= (1 << SLF_INUSE);
402 netif_start_queue(dev);
403 return 0;
404}
405
406/* Hook the destructor so we can free slcan devs at the right point in time */
407static void slc_free_netdev(struct net_device *dev)
408{
409 int i = dev->base_addr;
410 free_netdev(dev);
411 slcan_devs[i] = NULL;
412}
413
414static int slcan_change_mtu(struct net_device *dev, int new_mtu)
415{
416 return -EINVAL;
417}
418
419static const struct net_device_ops slc_netdev_ops = {
420 .ndo_open = slc_open,
421 .ndo_stop = slc_close,
422 .ndo_start_xmit = slc_xmit,
423 .ndo_change_mtu = slcan_change_mtu,
424};
425
426static void slc_setup(struct net_device *dev)
427{
428 dev->netdev_ops = &slc_netdev_ops;
429 dev->destructor = slc_free_netdev;
430
431 dev->hard_header_len = 0;
432 dev->addr_len = 0;
433 dev->tx_queue_len = 10;
434
435 dev->mtu = sizeof(struct can_frame);
436 dev->type = ARPHRD_CAN;
437
438 /* New-style flags. */
439 dev->flags = IFF_NOARP;
440 dev->features = NETIF_F_HW_CSUM;
441}
442
443/******************************************
444 Routines looking at TTY side.
445 ******************************************/
446
447/*
448 * Handle the 'receiver data ready' interrupt.
449 * This function is called by the 'tty_io' module in the kernel when
450 * a block of SLCAN data has been received, which can now be decapsulated
451 * and sent on to some IP layer for further processing. This will not
452 * be re-entered while running but other ldisc functions may be called
453 * in parallel
454 */
455
456static void slcan_receive_buf(struct tty_struct *tty,
457 const unsigned char *cp, char *fp, int count)
458{
459 struct slcan *sl = (struct slcan *) tty->disc_data;
460
461 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
462 return;
463
464 /* Read the characters out of the buffer */
465 while (count--) {
466 if (fp && *fp++) {
467 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
468 sl->dev->stats.rx_errors++;
469 cp++;
470 continue;
471 }
472 slcan_unesc(sl, *cp++);
473 }
474}
475
476/************************************
477 * slcan_open helper routines.
478 ************************************/
479
480/* Collect hanged up channels */
481static void slc_sync(void)
482{
483 int i;
484 struct net_device *dev;
485 struct slcan *sl;
486
487 for (i = 0; i < maxdev; i++) {
488 dev = slcan_devs[i];
489 if (dev == NULL)
490 break;
491
492 sl = netdev_priv(dev);
493 if (sl->tty)
494 continue;
495 if (dev->flags & IFF_UP)
496 dev_close(dev);
497 }
498}
499
500/* Find a free SLCAN channel, and link in this `tty' line. */
501static struct slcan *slc_alloc(dev_t line)
502{
503 int i;
504 char name[IFNAMSIZ];
505 struct net_device *dev = NULL;
506 struct slcan *sl;
507
508 for (i = 0; i < maxdev; i++) {
509 dev = slcan_devs[i];
510 if (dev == NULL)
511 break;
512
513 }
514
515 /* Sorry, too many, all slots in use */
516 if (i >= maxdev)
517 return NULL;
518
519 sprintf(name, "slcan%d", i);
520 dev = alloc_netdev(sizeof(*sl), name, slc_setup);
521 if (!dev)
522 return NULL;
523
524 dev->base_addr = i;
525 sl = netdev_priv(dev);
526
527 /* Initialize channel control data */
528 sl->magic = SLCAN_MAGIC;
529 sl->dev = dev;
530 spin_lock_init(&sl->lock);
531 slcan_devs[i] = dev;
532
533 return sl;
534}
535
536/*
537 * Open the high-level part of the SLCAN channel.
538 * This function is called by the TTY module when the
539 * SLCAN line discipline is called for. Because we are
540 * sure the tty line exists, we only have to link it to
541 * a free SLCAN channel...
542 *
543 * Called in process context serialized from other ldisc calls.
544 */
545
546static int slcan_open(struct tty_struct *tty)
547{
548 struct slcan *sl;
549 int err;
550
551 if (!capable(CAP_NET_ADMIN))
552 return -EPERM;
553
554 if (tty->ops->write == NULL)
555 return -EOPNOTSUPP;
556
557 /* RTnetlink lock is misused here to serialize concurrent
558 opens of slcan channels. There are better ways, but it is
559 the simplest one.
560 */
561 rtnl_lock();
562
563 /* Collect hanged up channels. */
564 slc_sync();
565
566 sl = tty->disc_data;
567
568 err = -EEXIST;
569 /* First make sure we're not already connected. */
570 if (sl && sl->magic == SLCAN_MAGIC)
571 goto err_exit;
572
573 /* OK. Find a free SLCAN channel to use. */
574 err = -ENFILE;
575 sl = slc_alloc(tty_devnum(tty));
576 if (sl == NULL)
577 goto err_exit;
578
579 sl->tty = tty;
580 tty->disc_data = sl;
581
582 if (!test_bit(SLF_INUSE, &sl->flags)) {
583 /* Perform the low-level SLCAN initialization. */
584 sl->rcount = 0;
585 sl->xleft = 0;
586
587 set_bit(SLF_INUSE, &sl->flags);
588
589 err = register_netdevice(sl->dev);
590 if (err)
591 goto err_free_chan;
592 }
593
594 /* Done. We have linked the TTY line to a channel. */
595 rtnl_unlock();
596 tty->receive_room = 65536; /* We don't flow control */
597
598 /* TTY layer expects 0 on success */
599 return 0;
600
601err_free_chan:
602 sl->tty = NULL;
603 tty->disc_data = NULL;
604 clear_bit(SLF_INUSE, &sl->flags);
605
606err_exit:
607 rtnl_unlock();
608
609 /* Count references from TTY module */
610 return err;
611}
612
613/*
614 * Close down a SLCAN channel.
615 * This means flushing out any pending queues, and then returning. This
616 * call is serialized against other ldisc functions.
617 *
618 * We also use this method for a hangup event.
619 */
620
621static void slcan_close(struct tty_struct *tty)
622{
623 struct slcan *sl = (struct slcan *) tty->disc_data;
624
625 /* First make sure we're connected. */
626 if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
627 return;
628
629 tty->disc_data = NULL;
630 sl->tty = NULL;
631
632 /* Flush network side */
633 unregister_netdev(sl->dev);
634 /* This will complete via sl_free_netdev */
635}
636
637static int slcan_hangup(struct tty_struct *tty)
638{
639 slcan_close(tty);
640 return 0;
641}
642
643/* Perform I/O control on an active SLCAN channel. */
644static int slcan_ioctl(struct tty_struct *tty, struct file *file,
645 unsigned int cmd, unsigned long arg)
646{
647 struct slcan *sl = (struct slcan *) tty->disc_data;
648 unsigned int tmp;
649
650 /* First make sure we're connected. */
651 if (!sl || sl->magic != SLCAN_MAGIC)
652 return -EINVAL;
653
654 switch (cmd) {
655 case SIOCGIFNAME:
656 tmp = strlen(sl->dev->name) + 1;
657 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
658 return -EFAULT;
659 return 0;
660
661 case SIOCSIFHWADDR:
662 return -EINVAL;
663
664 default:
665 return tty_mode_ioctl(tty, file, cmd, arg);
666 }
667}
668
669static struct tty_ldisc_ops slc_ldisc = {
670 .owner = THIS_MODULE,
671 .magic = TTY_LDISC_MAGIC,
672 .name = "slcan",
673 .open = slcan_open,
674 .close = slcan_close,
675 .hangup = slcan_hangup,
676 .ioctl = slcan_ioctl,
677 .receive_buf = slcan_receive_buf,
678 .write_wakeup = slcan_write_wakeup,
679};
680
681static int __init slcan_init(void)
682{
683 int status;
684
685 if (maxdev < 4)
686 maxdev = 4; /* Sanity */
687
688 printk(banner);
689 printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev);
690
691 slcan_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
692 if (!slcan_devs)
693 return -ENOMEM;
694
695 /* Fill in our line protocol discipline, and register it */
696 status = tty_register_ldisc(N_SLCAN, &slc_ldisc);
697 if (status) {
698 printk(KERN_ERR "slcan: can't register line discipline\n");
699 kfree(slcan_devs);
700 }
701 return status;
702}
703
704static void __exit slcan_exit(void)
705{
706 int i;
707 struct net_device *dev;
708 struct slcan *sl;
709 unsigned long timeout = jiffies + HZ;
710 int busy = 0;
711
712 if (slcan_devs == NULL)
713 return;
714
715 /* First of all: check for active disciplines and hangup them.
716 */
717 do {
718 if (busy)
719 msleep_interruptible(100);
720
721 busy = 0;
722 for (i = 0; i < maxdev; i++) {
723 dev = slcan_devs[i];
724 if (!dev)
725 continue;
726 sl = netdev_priv(dev);
727 spin_lock_bh(&sl->lock);
728 if (sl->tty) {
729 busy++;
730 tty_hangup(sl->tty);
731 }
732 spin_unlock_bh(&sl->lock);
733 }
734 } while (busy && time_before(jiffies, timeout));
735
736 /* FIXME: hangup is async so we should wait when doing this second
737 phase */
738
739 for (i = 0; i < maxdev; i++) {
740 dev = slcan_devs[i];
741 if (!dev)
742 continue;
743 slcan_devs[i] = NULL;
744
745 sl = netdev_priv(dev);
746 if (sl->tty) {
747 printk(KERN_ERR "%s: tty discipline still running\n",
748 dev->name);
749 /* Intentionally leak the control block. */
750 dev->destructor = NULL;
751 }
752
753 unregister_netdev(dev);
754 }
755
756 kfree(slcan_devs);
757 slcan_devs = NULL;
758
759 i = tty_unregister_ldisc(N_SLCAN);
760 if (i)
761 printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i);
762}
763
764module_init(slcan_init);
765module_exit(slcan_exit);
1/*
2 * slcan.c - serial line CAN interface driver (using tty line discipline)
3 *
4 * This file is derived from linux/drivers/net/slip/slip.c
5 *
6 * slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk>
7 * Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
8 * slcan.c Author : Oliver Hartkopp <socketcan@hartkopp.net>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation; either version 2 of the License, or (at your
13 * option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License along
21 * with this program; if not, write to the Free Software Foundation, Inc.,
22 * 59 Temple Place, Suite 330, Boston, MA 02111-1307. You can also get it
23 * at http://www.gnu.org/licenses/gpl.html
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
36 * DAMAGE.
37 *
38 */
39
40#include <linux/module.h>
41#include <linux/moduleparam.h>
42
43#include <linux/uaccess.h>
44#include <linux/bitops.h>
45#include <linux/string.h>
46#include <linux/tty.h>
47#include <linux/errno.h>
48#include <linux/netdevice.h>
49#include <linux/skbuff.h>
50#include <linux/rtnetlink.h>
51#include <linux/if_arp.h>
52#include <linux/if_ether.h>
53#include <linux/sched.h>
54#include <linux/delay.h>
55#include <linux/init.h>
56#include <linux/kernel.h>
57#include <linux/can.h>
58
59static __initdata const char banner[] =
60 KERN_INFO "slcan: serial line CAN interface driver\n";
61
62MODULE_ALIAS_LDISC(N_SLCAN);
63MODULE_DESCRIPTION("serial line CAN interface");
64MODULE_LICENSE("GPL");
65MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
66
67#define SLCAN_MAGIC 0x53CA
68
69static int maxdev = 10; /* MAX number of SLCAN channels;
70 This can be overridden with
71 insmod slcan.ko maxdev=nnn */
72module_param(maxdev, int, 0);
73MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
74
75/* maximum rx buffer len: extended CAN frame with timestamp */
76#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
77
78struct slcan {
79 int magic;
80
81 /* Various fields. */
82 struct tty_struct *tty; /* ptr to TTY structure */
83 struct net_device *dev; /* easy for intr handling */
84 spinlock_t lock;
85
86 /* These are pointers to the malloc()ed frame buffers. */
87 unsigned char rbuff[SLC_MTU]; /* receiver buffer */
88 int rcount; /* received chars counter */
89 unsigned char xbuff[SLC_MTU]; /* transmitter buffer */
90 unsigned char *xhead; /* pointer to next XMIT byte */
91 int xleft; /* bytes left in XMIT queue */
92
93 unsigned long flags; /* Flag values/ mode etc */
94#define SLF_INUSE 0 /* Channel in use */
95#define SLF_ERROR 1 /* Parity, etc. error */
96};
97
98static struct net_device **slcan_devs;
99
100 /************************************************************************
101 * SLCAN ENCAPSULATION FORMAT *
102 ************************************************************************/
103
104/*
105 * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
106 * frame format) a data length code (can_dlc) which can be from 0 to 8
107 * and up to <can_dlc> data bytes as payload.
108 * Additionally a CAN frame may become a remote transmission frame if the
109 * RTR-bit is set. This causes another ECU to send a CAN frame with the
110 * given can_id.
111 *
112 * The SLCAN ASCII representation of these different frame types is:
113 * <type> <id> <dlc> <data>*
114 *
115 * Extended frames (29 bit) are defined by capital characters in the type.
116 * RTR frames are defined as 'r' types - normal frames have 't' type:
117 * t => 11 bit data frame
118 * r => 11 bit RTR frame
119 * T => 29 bit data frame
120 * R => 29 bit RTR frame
121 *
122 * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
123 * The <dlc> is a one byte ASCII number ('0' - '8')
124 * The <data> section has at much ASCII Hex bytes as defined by the <dlc>
125 *
126 * Examples:
127 *
128 * t1230 : can_id 0x123, can_dlc 0, no data
129 * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33
130 * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55
131 * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request
132 *
133 */
134
135 /************************************************************************
136 * STANDARD SLCAN DECAPSULATION *
137 ************************************************************************/
138
139/* Send one completely decapsulated can_frame to the network layer */
140static void slc_bump(struct slcan *sl)
141{
142 struct sk_buff *skb;
143 struct can_frame cf;
144 int i, dlc_pos, tmp;
145 unsigned long ultmp;
146 char cmd = sl->rbuff[0];
147
148 if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R'))
149 return;
150
151 if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */
152 dlc_pos = 4; /* dlc position tiiid */
153 else
154 dlc_pos = 9; /* dlc position Tiiiiiiiid */
155
156 if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9')))
157 return;
158
159 cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */
160
161 sl->rbuff[dlc_pos] = 0; /* terminate can_id string */
162
163 if (strict_strtoul(sl->rbuff+1, 16, &ultmp))
164 return;
165
166 cf.can_id = ultmp;
167
168 if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */
169 cf.can_id |= CAN_EFF_FLAG;
170
171 if ((cmd | 0x20) == 'r') /* RTR frame */
172 cf.can_id |= CAN_RTR_FLAG;
173
174 *(u64 *) (&cf.data) = 0; /* clear payload */
175
176 for (i = 0, dlc_pos++; i < cf.can_dlc; i++) {
177 tmp = hex_to_bin(sl->rbuff[dlc_pos++]);
178 if (tmp < 0)
179 return;
180 cf.data[i] = (tmp << 4);
181 tmp = hex_to_bin(sl->rbuff[dlc_pos++]);
182 if (tmp < 0)
183 return;
184 cf.data[i] |= tmp;
185 }
186
187 skb = dev_alloc_skb(sizeof(struct can_frame));
188 if (!skb)
189 return;
190
191 skb->dev = sl->dev;
192 skb->protocol = htons(ETH_P_CAN);
193 skb->pkt_type = PACKET_BROADCAST;
194 skb->ip_summed = CHECKSUM_UNNECESSARY;
195 memcpy(skb_put(skb, sizeof(struct can_frame)),
196 &cf, sizeof(struct can_frame));
197 netif_rx_ni(skb);
198
199 sl->dev->stats.rx_packets++;
200 sl->dev->stats.rx_bytes += cf.can_dlc;
201}
202
203/* parse tty input stream */
204static void slcan_unesc(struct slcan *sl, unsigned char s)
205{
206
207 if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
208 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
209 (sl->rcount > 4)) {
210 slc_bump(sl);
211 }
212 sl->rcount = 0;
213 } else {
214 if (!test_bit(SLF_ERROR, &sl->flags)) {
215 if (sl->rcount < SLC_MTU) {
216 sl->rbuff[sl->rcount++] = s;
217 return;
218 } else {
219 sl->dev->stats.rx_over_errors++;
220 set_bit(SLF_ERROR, &sl->flags);
221 }
222 }
223 }
224}
225
226 /************************************************************************
227 * STANDARD SLCAN ENCAPSULATION *
228 ************************************************************************/
229
230/* Encapsulate one can_frame and stuff into a TTY queue. */
231static void slc_encaps(struct slcan *sl, struct can_frame *cf)
232{
233 int actual, idx, i;
234 char cmd;
235
236 if (cf->can_id & CAN_RTR_FLAG)
237 cmd = 'R'; /* becomes 'r' in standard frame format */
238 else
239 cmd = 'T'; /* becomes 't' in standard frame format */
240
241 if (cf->can_id & CAN_EFF_FLAG)
242 sprintf(sl->xbuff, "%c%08X%d", cmd,
243 cf->can_id & CAN_EFF_MASK, cf->can_dlc);
244 else
245 sprintf(sl->xbuff, "%c%03X%d", cmd | 0x20,
246 cf->can_id & CAN_SFF_MASK, cf->can_dlc);
247
248 idx = strlen(sl->xbuff);
249
250 for (i = 0; i < cf->can_dlc; i++)
251 sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]);
252
253 strcat(sl->xbuff, "\r"); /* add terminating character */
254
255 /* Order of next two lines is *very* important.
256 * When we are sending a little amount of data,
257 * the transfer may be completed inside the ops->write()
258 * routine, because it's running with interrupts enabled.
259 * In this case we *never* got WRITE_WAKEUP event,
260 * if we did not request it before write operation.
261 * 14 Oct 1994 Dmitry Gorodchanin.
262 */
263 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
264 actual = sl->tty->ops->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
265 sl->xleft = strlen(sl->xbuff) - actual;
266 sl->xhead = sl->xbuff + actual;
267 sl->dev->stats.tx_bytes += cf->can_dlc;
268}
269
270/*
271 * Called by the driver when there's room for more data. If we have
272 * more packets to send, we send them here.
273 */
274static void slcan_write_wakeup(struct tty_struct *tty)
275{
276 int actual;
277 struct slcan *sl = (struct slcan *) tty->disc_data;
278
279 /* First make sure we're connected. */
280 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
281 return;
282
283 if (sl->xleft <= 0) {
284 /* Now serial buffer is almost free & we can start
285 * transmission of another packet */
286 sl->dev->stats.tx_packets++;
287 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
288 netif_wake_queue(sl->dev);
289 return;
290 }
291
292 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
293 sl->xleft -= actual;
294 sl->xhead += actual;
295}
296
297/* Send a can_frame to a TTY queue. */
298static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
299{
300 struct slcan *sl = netdev_priv(dev);
301
302 if (skb->len != sizeof(struct can_frame))
303 goto out;
304
305 spin_lock(&sl->lock);
306 if (!netif_running(dev)) {
307 spin_unlock(&sl->lock);
308 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
309 goto out;
310 }
311 if (sl->tty == NULL) {
312 spin_unlock(&sl->lock);
313 goto out;
314 }
315
316 netif_stop_queue(sl->dev);
317 slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
318 spin_unlock(&sl->lock);
319
320out:
321 kfree_skb(skb);
322 return NETDEV_TX_OK;
323}
324
325
326/******************************************
327 * Routines looking at netdevice side.
328 ******************************************/
329
330/* Netdevice UP -> DOWN routine */
331static int slc_close(struct net_device *dev)
332{
333 struct slcan *sl = netdev_priv(dev);
334
335 spin_lock_bh(&sl->lock);
336 if (sl->tty) {
337 /* TTY discipline is running. */
338 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
339 }
340 netif_stop_queue(dev);
341 sl->rcount = 0;
342 sl->xleft = 0;
343 spin_unlock_bh(&sl->lock);
344
345 return 0;
346}
347
348/* Netdevice DOWN -> UP routine */
349static int slc_open(struct net_device *dev)
350{
351 struct slcan *sl = netdev_priv(dev);
352
353 if (sl->tty == NULL)
354 return -ENODEV;
355
356 sl->flags &= (1 << SLF_INUSE);
357 netif_start_queue(dev);
358 return 0;
359}
360
361/* Hook the destructor so we can free slcan devs at the right point in time */
362static void slc_free_netdev(struct net_device *dev)
363{
364 int i = dev->base_addr;
365 free_netdev(dev);
366 slcan_devs[i] = NULL;
367}
368
369static const struct net_device_ops slc_netdev_ops = {
370 .ndo_open = slc_open,
371 .ndo_stop = slc_close,
372 .ndo_start_xmit = slc_xmit,
373};
374
375static void slc_setup(struct net_device *dev)
376{
377 dev->netdev_ops = &slc_netdev_ops;
378 dev->destructor = slc_free_netdev;
379
380 dev->hard_header_len = 0;
381 dev->addr_len = 0;
382 dev->tx_queue_len = 10;
383
384 dev->mtu = sizeof(struct can_frame);
385 dev->type = ARPHRD_CAN;
386
387 /* New-style flags. */
388 dev->flags = IFF_NOARP;
389 dev->features = NETIF_F_HW_CSUM;
390}
391
392/******************************************
393 Routines looking at TTY side.
394 ******************************************/
395
396/*
397 * Handle the 'receiver data ready' interrupt.
398 * This function is called by the 'tty_io' module in the kernel when
399 * a block of SLCAN data has been received, which can now be decapsulated
400 * and sent on to some IP layer for further processing. This will not
401 * be re-entered while running but other ldisc functions may be called
402 * in parallel
403 */
404
405static void slcan_receive_buf(struct tty_struct *tty,
406 const unsigned char *cp, char *fp, int count)
407{
408 struct slcan *sl = (struct slcan *) tty->disc_data;
409
410 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
411 return;
412
413 /* Read the characters out of the buffer */
414 while (count--) {
415 if (fp && *fp++) {
416 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
417 sl->dev->stats.rx_errors++;
418 cp++;
419 continue;
420 }
421 slcan_unesc(sl, *cp++);
422 }
423}
424
425/************************************
426 * slcan_open helper routines.
427 ************************************/
428
429/* Collect hanged up channels */
430static void slc_sync(void)
431{
432 int i;
433 struct net_device *dev;
434 struct slcan *sl;
435
436 for (i = 0; i < maxdev; i++) {
437 dev = slcan_devs[i];
438 if (dev == NULL)
439 break;
440
441 sl = netdev_priv(dev);
442 if (sl->tty)
443 continue;
444 if (dev->flags & IFF_UP)
445 dev_close(dev);
446 }
447}
448
449/* Find a free SLCAN channel, and link in this `tty' line. */
450static struct slcan *slc_alloc(dev_t line)
451{
452 int i;
453 char name[IFNAMSIZ];
454 struct net_device *dev = NULL;
455 struct slcan *sl;
456
457 for (i = 0; i < maxdev; i++) {
458 dev = slcan_devs[i];
459 if (dev == NULL)
460 break;
461
462 }
463
464 /* Sorry, too many, all slots in use */
465 if (i >= maxdev)
466 return NULL;
467
468 sprintf(name, "slcan%d", i);
469 dev = alloc_netdev(sizeof(*sl), name, slc_setup);
470 if (!dev)
471 return NULL;
472
473 dev->base_addr = i;
474 sl = netdev_priv(dev);
475
476 /* Initialize channel control data */
477 sl->magic = SLCAN_MAGIC;
478 sl->dev = dev;
479 spin_lock_init(&sl->lock);
480 slcan_devs[i] = dev;
481
482 return sl;
483}
484
485/*
486 * Open the high-level part of the SLCAN channel.
487 * This function is called by the TTY module when the
488 * SLCAN line discipline is called for. Because we are
489 * sure the tty line exists, we only have to link it to
490 * a free SLCAN channel...
491 *
492 * Called in process context serialized from other ldisc calls.
493 */
494
495static int slcan_open(struct tty_struct *tty)
496{
497 struct slcan *sl;
498 int err;
499
500 if (!capable(CAP_NET_ADMIN))
501 return -EPERM;
502
503 if (tty->ops->write == NULL)
504 return -EOPNOTSUPP;
505
506 /* RTnetlink lock is misused here to serialize concurrent
507 opens of slcan channels. There are better ways, but it is
508 the simplest one.
509 */
510 rtnl_lock();
511
512 /* Collect hanged up channels. */
513 slc_sync();
514
515 sl = tty->disc_data;
516
517 err = -EEXIST;
518 /* First make sure we're not already connected. */
519 if (sl && sl->magic == SLCAN_MAGIC)
520 goto err_exit;
521
522 /* OK. Find a free SLCAN channel to use. */
523 err = -ENFILE;
524 sl = slc_alloc(tty_devnum(tty));
525 if (sl == NULL)
526 goto err_exit;
527
528 sl->tty = tty;
529 tty->disc_data = sl;
530
531 if (!test_bit(SLF_INUSE, &sl->flags)) {
532 /* Perform the low-level SLCAN initialization. */
533 sl->rcount = 0;
534 sl->xleft = 0;
535
536 set_bit(SLF_INUSE, &sl->flags);
537
538 err = register_netdevice(sl->dev);
539 if (err)
540 goto err_free_chan;
541 }
542
543 /* Done. We have linked the TTY line to a channel. */
544 rtnl_unlock();
545 tty->receive_room = 65536; /* We don't flow control */
546
547 /* TTY layer expects 0 on success */
548 return 0;
549
550err_free_chan:
551 sl->tty = NULL;
552 tty->disc_data = NULL;
553 clear_bit(SLF_INUSE, &sl->flags);
554
555err_exit:
556 rtnl_unlock();
557
558 /* Count references from TTY module */
559 return err;
560}
561
562/*
563 * Close down a SLCAN channel.
564 * This means flushing out any pending queues, and then returning. This
565 * call is serialized against other ldisc functions.
566 *
567 * We also use this method for a hangup event.
568 */
569
570static void slcan_close(struct tty_struct *tty)
571{
572 struct slcan *sl = (struct slcan *) tty->disc_data;
573
574 /* First make sure we're connected. */
575 if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
576 return;
577
578 tty->disc_data = NULL;
579 sl->tty = NULL;
580
581 /* Flush network side */
582 unregister_netdev(sl->dev);
583 /* This will complete via sl_free_netdev */
584}
585
586static int slcan_hangup(struct tty_struct *tty)
587{
588 slcan_close(tty);
589 return 0;
590}
591
592/* Perform I/O control on an active SLCAN channel. */
593static int slcan_ioctl(struct tty_struct *tty, struct file *file,
594 unsigned int cmd, unsigned long arg)
595{
596 struct slcan *sl = (struct slcan *) tty->disc_data;
597 unsigned int tmp;
598
599 /* First make sure we're connected. */
600 if (!sl || sl->magic != SLCAN_MAGIC)
601 return -EINVAL;
602
603 switch (cmd) {
604 case SIOCGIFNAME:
605 tmp = strlen(sl->dev->name) + 1;
606 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
607 return -EFAULT;
608 return 0;
609
610 case SIOCSIFHWADDR:
611 return -EINVAL;
612
613 default:
614 return tty_mode_ioctl(tty, file, cmd, arg);
615 }
616}
617
618static struct tty_ldisc_ops slc_ldisc = {
619 .owner = THIS_MODULE,
620 .magic = TTY_LDISC_MAGIC,
621 .name = "slcan",
622 .open = slcan_open,
623 .close = slcan_close,
624 .hangup = slcan_hangup,
625 .ioctl = slcan_ioctl,
626 .receive_buf = slcan_receive_buf,
627 .write_wakeup = slcan_write_wakeup,
628};
629
630static int __init slcan_init(void)
631{
632 int status;
633
634 if (maxdev < 4)
635 maxdev = 4; /* Sanity */
636
637 printk(banner);
638 printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev);
639
640 slcan_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
641 if (!slcan_devs)
642 return -ENOMEM;
643
644 /* Fill in our line protocol discipline, and register it */
645 status = tty_register_ldisc(N_SLCAN, &slc_ldisc);
646 if (status) {
647 printk(KERN_ERR "slcan: can't register line discipline\n");
648 kfree(slcan_devs);
649 }
650 return status;
651}
652
653static void __exit slcan_exit(void)
654{
655 int i;
656 struct net_device *dev;
657 struct slcan *sl;
658 unsigned long timeout = jiffies + HZ;
659 int busy = 0;
660
661 if (slcan_devs == NULL)
662 return;
663
664 /* First of all: check for active disciplines and hangup them.
665 */
666 do {
667 if (busy)
668 msleep_interruptible(100);
669
670 busy = 0;
671 for (i = 0; i < maxdev; i++) {
672 dev = slcan_devs[i];
673 if (!dev)
674 continue;
675 sl = netdev_priv(dev);
676 spin_lock_bh(&sl->lock);
677 if (sl->tty) {
678 busy++;
679 tty_hangup(sl->tty);
680 }
681 spin_unlock_bh(&sl->lock);
682 }
683 } while (busy && time_before(jiffies, timeout));
684
685 /* FIXME: hangup is async so we should wait when doing this second
686 phase */
687
688 for (i = 0; i < maxdev; i++) {
689 dev = slcan_devs[i];
690 if (!dev)
691 continue;
692 slcan_devs[i] = NULL;
693
694 sl = netdev_priv(dev);
695 if (sl->tty) {
696 printk(KERN_ERR "%s: tty discipline still running\n",
697 dev->name);
698 /* Intentionally leak the control block. */
699 dev->destructor = NULL;
700 }
701
702 unregister_netdev(dev);
703 }
704
705 kfree(slcan_devs);
706 slcan_devs = NULL;
707
708 i = tty_unregister_ldisc(N_SLCAN);
709 if (i)
710 printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i);
711}
712
713module_init(slcan_init);
714module_exit(slcan_exit);