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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, 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/workqueue.h>
56#include <linux/can.h>
57#include <linux/can/skb.h>
58#include <linux/can/can-ml.h>
59
60MODULE_ALIAS_LDISC(N_SLCAN);
61MODULE_DESCRIPTION("serial line CAN interface");
62MODULE_LICENSE("GPL");
63MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
64
65#define SLCAN_MAGIC 0x53CA
66
67static int maxdev = 10; /* MAX number of SLCAN channels;
68 This can be overridden with
69 insmod slcan.ko maxdev=nnn */
70module_param(maxdev, int, 0);
71MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
72
73/* maximum rx buffer len: extended CAN frame with timestamp */
74#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
75
76#define SLC_CMD_LEN 1
77#define SLC_SFF_ID_LEN 3
78#define SLC_EFF_ID_LEN 8
79
80struct slcan {
81 int magic;
82
83 /* Various fields. */
84 struct tty_struct *tty; /* ptr to TTY structure */
85 struct net_device *dev; /* easy for intr handling */
86 spinlock_t lock;
87 struct work_struct tx_work; /* Flushes transmit buffer */
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 (len) which can be from 0 to 8
110 * and up to <len> 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, len 0, no data
132 * t4563112233 : can_id 0x456, len 3, data 0x11 0x22 0x33
133 * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, len 2, data 0xAA 0x55
134 * r1230 : can_id 0x123, len 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 memset(&cf, 0, sizeof(cf));
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.len = 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.len = 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 len from sanitized ASCII value */
185 if (cf.len >= '0' && cf.len < '9')
186 cf.len -= '0';
187 else
188 return;
189
190 /* RTR frames may have a dlc > 0 but they never have any data bytes */
191 if (!(cf.can_id & CAN_RTR_FLAG)) {
192 for (i = 0; i < cf.len; i++) {
193 tmp = hex_to_bin(*cmd++);
194 if (tmp < 0)
195 return;
196 cf.data[i] = (tmp << 4);
197 tmp = hex_to_bin(*cmd++);
198 if (tmp < 0)
199 return;
200 cf.data[i] |= tmp;
201 }
202 }
203
204 skb = dev_alloc_skb(sizeof(struct can_frame) +
205 sizeof(struct can_skb_priv));
206 if (!skb)
207 return;
208
209 skb->dev = sl->dev;
210 skb->protocol = htons(ETH_P_CAN);
211 skb->pkt_type = PACKET_BROADCAST;
212 skb->ip_summed = CHECKSUM_UNNECESSARY;
213
214 can_skb_reserve(skb);
215 can_skb_prv(skb)->ifindex = sl->dev->ifindex;
216 can_skb_prv(skb)->skbcnt = 0;
217
218 skb_put_data(skb, &cf, sizeof(struct can_frame));
219
220 sl->dev->stats.rx_packets++;
221 sl->dev->stats.rx_bytes += cf.len;
222 netif_rx_ni(skb);
223}
224
225/* parse tty input stream */
226static void slcan_unesc(struct slcan *sl, unsigned char s)
227{
228 if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
229 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
230 (sl->rcount > 4)) {
231 slc_bump(sl);
232 }
233 sl->rcount = 0;
234 } else {
235 if (!test_bit(SLF_ERROR, &sl->flags)) {
236 if (sl->rcount < SLC_MTU) {
237 sl->rbuff[sl->rcount++] = s;
238 return;
239 } else {
240 sl->dev->stats.rx_over_errors++;
241 set_bit(SLF_ERROR, &sl->flags);
242 }
243 }
244 }
245}
246
247 /************************************************************************
248 * STANDARD SLCAN ENCAPSULATION *
249 ************************************************************************/
250
251/* Encapsulate one can_frame and stuff into a TTY queue. */
252static void slc_encaps(struct slcan *sl, struct can_frame *cf)
253{
254 int actual, i;
255 unsigned char *pos;
256 unsigned char *endpos;
257 canid_t id = cf->can_id;
258
259 pos = sl->xbuff;
260
261 if (cf->can_id & CAN_RTR_FLAG)
262 *pos = 'R'; /* becomes 'r' in standard frame format (SFF) */
263 else
264 *pos = 'T'; /* becomes 't' in standard frame format (SSF) */
265
266 /* determine number of chars for the CAN-identifier */
267 if (cf->can_id & CAN_EFF_FLAG) {
268 id &= CAN_EFF_MASK;
269 endpos = pos + SLC_EFF_ID_LEN;
270 } else {
271 *pos |= 0x20; /* convert R/T to lower case for SFF */
272 id &= CAN_SFF_MASK;
273 endpos = pos + SLC_SFF_ID_LEN;
274 }
275
276 /* build 3 (SFF) or 8 (EFF) digit CAN identifier */
277 pos++;
278 while (endpos >= pos) {
279 *endpos-- = hex_asc_upper[id & 0xf];
280 id >>= 4;
281 }
282
283 pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN;
284
285 *pos++ = cf->len + '0';
286
287 /* RTR frames may have a dlc > 0 but they never have any data bytes */
288 if (!(cf->can_id & CAN_RTR_FLAG)) {
289 for (i = 0; i < cf->len; i++)
290 pos = hex_byte_pack_upper(pos, cf->data[i]);
291 }
292
293 *pos++ = '\r';
294
295 /* Order of next two lines is *very* important.
296 * When we are sending a little amount of data,
297 * the transfer may be completed inside the ops->write()
298 * routine, because it's running with interrupts enabled.
299 * In this case we *never* got WRITE_WAKEUP event,
300 * if we did not request it before write operation.
301 * 14 Oct 1994 Dmitry Gorodchanin.
302 */
303 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
304 actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff);
305 sl->xleft = (pos - sl->xbuff) - actual;
306 sl->xhead = sl->xbuff + actual;
307 sl->dev->stats.tx_bytes += cf->len;
308}
309
310/* Write out any remaining transmit buffer. Scheduled when tty is writable */
311static void slcan_transmit(struct work_struct *work)
312{
313 struct slcan *sl = container_of(work, struct slcan, tx_work);
314 int actual;
315
316 spin_lock_bh(&sl->lock);
317 /* First make sure we're connected. */
318 if (!sl->tty || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) {
319 spin_unlock_bh(&sl->lock);
320 return;
321 }
322
323 if (sl->xleft <= 0) {
324 /* Now serial buffer is almost free & we can start
325 * transmission of another packet */
326 sl->dev->stats.tx_packets++;
327 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
328 spin_unlock_bh(&sl->lock);
329 netif_wake_queue(sl->dev);
330 return;
331 }
332
333 actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
334 sl->xleft -= actual;
335 sl->xhead += actual;
336 spin_unlock_bh(&sl->lock);
337}
338
339/*
340 * Called by the driver when there's room for more data.
341 * Schedule the transmit.
342 */
343static void slcan_write_wakeup(struct tty_struct *tty)
344{
345 struct slcan *sl;
346
347 rcu_read_lock();
348 sl = rcu_dereference(tty->disc_data);
349 if (sl)
350 schedule_work(&sl->tx_work);
351 rcu_read_unlock();
352}
353
354/* Send a can_frame to a TTY queue. */
355static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
356{
357 struct slcan *sl = netdev_priv(dev);
358
359 if (skb->len != CAN_MTU)
360 goto out;
361
362 spin_lock(&sl->lock);
363 if (!netif_running(dev)) {
364 spin_unlock(&sl->lock);
365 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
366 goto out;
367 }
368 if (sl->tty == NULL) {
369 spin_unlock(&sl->lock);
370 goto out;
371 }
372
373 netif_stop_queue(sl->dev);
374 slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
375 spin_unlock(&sl->lock);
376
377out:
378 kfree_skb(skb);
379 return NETDEV_TX_OK;
380}
381
382
383/******************************************
384 * Routines looking at netdevice side.
385 ******************************************/
386
387/* Netdevice UP -> DOWN routine */
388static int slc_close(struct net_device *dev)
389{
390 struct slcan *sl = netdev_priv(dev);
391
392 spin_lock_bh(&sl->lock);
393 if (sl->tty) {
394 /* TTY discipline is running. */
395 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
396 }
397 netif_stop_queue(dev);
398 sl->rcount = 0;
399 sl->xleft = 0;
400 spin_unlock_bh(&sl->lock);
401
402 return 0;
403}
404
405/* Netdevice DOWN -> UP routine */
406static int slc_open(struct net_device *dev)
407{
408 struct slcan *sl = netdev_priv(dev);
409
410 if (sl->tty == NULL)
411 return -ENODEV;
412
413 sl->flags &= (1 << SLF_INUSE);
414 netif_start_queue(dev);
415 return 0;
416}
417
418/* Hook the destructor so we can free slcan devs at the right point in time */
419static void slc_free_netdev(struct net_device *dev)
420{
421 int i = dev->base_addr;
422
423 slcan_devs[i] = NULL;
424}
425
426static int slcan_change_mtu(struct net_device *dev, int new_mtu)
427{
428 return -EINVAL;
429}
430
431static const struct net_device_ops slc_netdev_ops = {
432 .ndo_open = slc_open,
433 .ndo_stop = slc_close,
434 .ndo_start_xmit = slc_xmit,
435 .ndo_change_mtu = slcan_change_mtu,
436};
437
438static void slc_setup(struct net_device *dev)
439{
440 dev->netdev_ops = &slc_netdev_ops;
441 dev->needs_free_netdev = true;
442 dev->priv_destructor = slc_free_netdev;
443
444 dev->hard_header_len = 0;
445 dev->addr_len = 0;
446 dev->tx_queue_len = 10;
447
448 dev->mtu = CAN_MTU;
449 dev->type = ARPHRD_CAN;
450
451 /* New-style flags. */
452 dev->flags = IFF_NOARP;
453 dev->features = NETIF_F_HW_CSUM;
454}
455
456/******************************************
457 Routines looking at TTY side.
458 ******************************************/
459
460/*
461 * Handle the 'receiver data ready' interrupt.
462 * This function is called by the 'tty_io' module in the kernel when
463 * a block of SLCAN data has been received, which can now be decapsulated
464 * and sent on to some IP layer for further processing. This will not
465 * be re-entered while running but other ldisc functions may be called
466 * in parallel
467 */
468
469static void slcan_receive_buf(struct tty_struct *tty,
470 const unsigned char *cp, const char *fp,
471 int count)
472{
473 struct slcan *sl = (struct slcan *) tty->disc_data;
474
475 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
476 return;
477
478 /* Read the characters out of the buffer */
479 while (count--) {
480 if (fp && *fp++) {
481 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
482 sl->dev->stats.rx_errors++;
483 cp++;
484 continue;
485 }
486 slcan_unesc(sl, *cp++);
487 }
488}
489
490/************************************
491 * slcan_open helper routines.
492 ************************************/
493
494/* Collect hanged up channels */
495static void slc_sync(void)
496{
497 int i;
498 struct net_device *dev;
499 struct slcan *sl;
500
501 for (i = 0; i < maxdev; i++) {
502 dev = slcan_devs[i];
503 if (dev == NULL)
504 break;
505
506 sl = netdev_priv(dev);
507 if (sl->tty)
508 continue;
509 if (dev->flags & IFF_UP)
510 dev_close(dev);
511 }
512}
513
514/* Find a free SLCAN channel, and link in this `tty' line. */
515static struct slcan *slc_alloc(void)
516{
517 int i;
518 char name[IFNAMSIZ];
519 struct net_device *dev = NULL;
520 struct can_ml_priv *can_ml;
521 struct slcan *sl;
522 int size;
523
524 for (i = 0; i < maxdev; i++) {
525 dev = slcan_devs[i];
526 if (dev == NULL)
527 break;
528
529 }
530
531 /* Sorry, too many, all slots in use */
532 if (i >= maxdev)
533 return NULL;
534
535 sprintf(name, "slcan%d", i);
536 size = ALIGN(sizeof(*sl), NETDEV_ALIGN) + sizeof(struct can_ml_priv);
537 dev = alloc_netdev(size, name, NET_NAME_UNKNOWN, slc_setup);
538 if (!dev)
539 return NULL;
540
541 dev->base_addr = i;
542 sl = netdev_priv(dev);
543 can_ml = (void *)sl + ALIGN(sizeof(*sl), NETDEV_ALIGN);
544 can_set_ml_priv(dev, can_ml);
545
546 /* Initialize channel control data */
547 sl->magic = SLCAN_MAGIC;
548 sl->dev = dev;
549 spin_lock_init(&sl->lock);
550 INIT_WORK(&sl->tx_work, slcan_transmit);
551 slcan_devs[i] = dev;
552
553 return sl;
554}
555
556/*
557 * Open the high-level part of the SLCAN channel.
558 * This function is called by the TTY module when the
559 * SLCAN line discipline is called for. Because we are
560 * sure the tty line exists, we only have to link it to
561 * a free SLCAN channel...
562 *
563 * Called in process context serialized from other ldisc calls.
564 */
565
566static int slcan_open(struct tty_struct *tty)
567{
568 struct slcan *sl;
569 int err;
570
571 if (!capable(CAP_NET_ADMIN))
572 return -EPERM;
573
574 if (tty->ops->write == NULL)
575 return -EOPNOTSUPP;
576
577 /* RTnetlink lock is misused here to serialize concurrent
578 opens of slcan channels. There are better ways, but it is
579 the simplest one.
580 */
581 rtnl_lock();
582
583 /* Collect hanged up channels. */
584 slc_sync();
585
586 sl = tty->disc_data;
587
588 err = -EEXIST;
589 /* First make sure we're not already connected. */
590 if (sl && sl->magic == SLCAN_MAGIC)
591 goto err_exit;
592
593 /* OK. Find a free SLCAN channel to use. */
594 err = -ENFILE;
595 sl = slc_alloc();
596 if (sl == NULL)
597 goto err_exit;
598
599 sl->tty = tty;
600 tty->disc_data = sl;
601
602 if (!test_bit(SLF_INUSE, &sl->flags)) {
603 /* Perform the low-level SLCAN initialization. */
604 sl->rcount = 0;
605 sl->xleft = 0;
606
607 set_bit(SLF_INUSE, &sl->flags);
608
609 err = register_netdevice(sl->dev);
610 if (err)
611 goto err_free_chan;
612 }
613
614 /* Done. We have linked the TTY line to a channel. */
615 rtnl_unlock();
616 tty->receive_room = 65536; /* We don't flow control */
617
618 /* TTY layer expects 0 on success */
619 return 0;
620
621err_free_chan:
622 sl->tty = NULL;
623 tty->disc_data = NULL;
624 clear_bit(SLF_INUSE, &sl->flags);
625 slc_free_netdev(sl->dev);
626 /* do not call free_netdev before rtnl_unlock */
627 rtnl_unlock();
628 free_netdev(sl->dev);
629 return err;
630
631err_exit:
632 rtnl_unlock();
633
634 /* Count references from TTY module */
635 return err;
636}
637
638/*
639 * Close down a SLCAN channel.
640 * This means flushing out any pending queues, and then returning. This
641 * call is serialized against other ldisc functions.
642 *
643 * We also use this method for a hangup event.
644 */
645
646static void slcan_close(struct tty_struct *tty)
647{
648 struct slcan *sl = (struct slcan *) tty->disc_data;
649
650 /* First make sure we're connected. */
651 if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
652 return;
653
654 spin_lock_bh(&sl->lock);
655 rcu_assign_pointer(tty->disc_data, NULL);
656 sl->tty = NULL;
657 spin_unlock_bh(&sl->lock);
658
659 synchronize_rcu();
660 flush_work(&sl->tx_work);
661
662 /* Flush network side */
663 unregister_netdev(sl->dev);
664 /* This will complete via sl_free_netdev */
665}
666
667static int slcan_hangup(struct tty_struct *tty)
668{
669 slcan_close(tty);
670 return 0;
671}
672
673/* Perform I/O control on an active SLCAN channel. */
674static int slcan_ioctl(struct tty_struct *tty, struct file *file,
675 unsigned int cmd, unsigned long arg)
676{
677 struct slcan *sl = (struct slcan *) tty->disc_data;
678 unsigned int tmp;
679
680 /* First make sure we're connected. */
681 if (!sl || sl->magic != SLCAN_MAGIC)
682 return -EINVAL;
683
684 switch (cmd) {
685 case SIOCGIFNAME:
686 tmp = strlen(sl->dev->name) + 1;
687 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
688 return -EFAULT;
689 return 0;
690
691 case SIOCSIFHWADDR:
692 return -EINVAL;
693
694 default:
695 return tty_mode_ioctl(tty, file, cmd, arg);
696 }
697}
698
699static struct tty_ldisc_ops slc_ldisc = {
700 .owner = THIS_MODULE,
701 .num = N_SLCAN,
702 .name = "slcan",
703 .open = slcan_open,
704 .close = slcan_close,
705 .hangup = slcan_hangup,
706 .ioctl = slcan_ioctl,
707 .receive_buf = slcan_receive_buf,
708 .write_wakeup = slcan_write_wakeup,
709};
710
711static int __init slcan_init(void)
712{
713 int status;
714
715 if (maxdev < 4)
716 maxdev = 4; /* Sanity */
717
718 pr_info("slcan: serial line CAN interface driver\n");
719 pr_info("slcan: %d dynamic interface channels.\n", maxdev);
720
721 slcan_devs = kcalloc(maxdev, sizeof(struct net_device *), GFP_KERNEL);
722 if (!slcan_devs)
723 return -ENOMEM;
724
725 /* Fill in our line protocol discipline, and register it */
726 status = tty_register_ldisc(&slc_ldisc);
727 if (status) {
728 printk(KERN_ERR "slcan: can't register line discipline\n");
729 kfree(slcan_devs);
730 }
731 return status;
732}
733
734static void __exit slcan_exit(void)
735{
736 int i;
737 struct net_device *dev;
738 struct slcan *sl;
739 unsigned long timeout = jiffies + HZ;
740 int busy = 0;
741
742 if (slcan_devs == NULL)
743 return;
744
745 /* First of all: check for active disciplines and hangup them.
746 */
747 do {
748 if (busy)
749 msleep_interruptible(100);
750
751 busy = 0;
752 for (i = 0; i < maxdev; i++) {
753 dev = slcan_devs[i];
754 if (!dev)
755 continue;
756 sl = netdev_priv(dev);
757 spin_lock_bh(&sl->lock);
758 if (sl->tty) {
759 busy++;
760 tty_hangup(sl->tty);
761 }
762 spin_unlock_bh(&sl->lock);
763 }
764 } while (busy && time_before(jiffies, timeout));
765
766 /* FIXME: hangup is async so we should wait when doing this second
767 phase */
768
769 for (i = 0; i < maxdev; i++) {
770 dev = slcan_devs[i];
771 if (!dev)
772 continue;
773 slcan_devs[i] = NULL;
774
775 sl = netdev_priv(dev);
776 if (sl->tty) {
777 printk(KERN_ERR "%s: tty discipline still running\n",
778 dev->name);
779 }
780
781 unregister_netdev(dev);
782 }
783
784 kfree(slcan_devs);
785 slcan_devs = NULL;
786
787 tty_unregister_ldisc(&slc_ldisc);
788}
789
790module_init(slcan_init);
791module_exit(slcan_exit);