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
60 MODULE_ALIAS_LDISC(N_SLCAN);
61 MODULE_DESCRIPTION("serial line CAN interface");
62 MODULE_LICENSE("GPL");
63 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
64
65 #define SLCAN_MAGIC 0x53CA
66
67 static int maxdev = 10; /* MAX number of SLCAN channels;
68 This can be overridden with
69 insmod slcan.ko maxdev=nnn */
70 module_param(maxdev, int, 0);
71 MODULE_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
80 struct 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
101 static 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 */
slc_bump(struct slcan * sl)143 static 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 can_skb_prv(skb)->skbcnt = 0;
219
220 skb_put_data(skb, &cf, sizeof(struct can_frame));
221
222 sl->dev->stats.rx_packets++;
223 sl->dev->stats.rx_bytes += cf.can_dlc;
224 netif_rx_ni(skb);
225 }
226
227 /* parse tty input stream */
slcan_unesc(struct slcan * sl,unsigned char s)228 static 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. */
slc_encaps(struct slcan * sl,struct can_frame * cf)254 static 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 /* Write out any remaining transmit buffer. Scheduled when tty is writable */
slcan_transmit(struct work_struct * work)313 static void slcan_transmit(struct work_struct *work)
314 {
315 struct slcan *sl = container_of(work, struct slcan, tx_work);
316 int actual;
317
318 spin_lock_bh(&sl->lock);
319 /* First make sure we're connected. */
320 if (!sl->tty || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) {
321 spin_unlock_bh(&sl->lock);
322 return;
323 }
324
325 if (sl->xleft <= 0) {
326 /* Now serial buffer is almost free & we can start
327 * transmission of another packet */
328 sl->dev->stats.tx_packets++;
329 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
330 spin_unlock_bh(&sl->lock);
331 netif_wake_queue(sl->dev);
332 return;
333 }
334
335 actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
336 sl->xleft -= actual;
337 sl->xhead += actual;
338 spin_unlock_bh(&sl->lock);
339 }
340
341 /*
342 * Called by the driver when there's room for more data.
343 * Schedule the transmit.
344 */
slcan_write_wakeup(struct tty_struct * tty)345 static void slcan_write_wakeup(struct tty_struct *tty)
346 {
347 struct slcan *sl = tty->disc_data;
348
349 schedule_work(&sl->tx_work);
350 }
351
352 /* Send a can_frame to a TTY queue. */
slc_xmit(struct sk_buff * skb,struct net_device * dev)353 static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
354 {
355 struct slcan *sl = netdev_priv(dev);
356
357 if (skb->len != CAN_MTU)
358 goto out;
359
360 spin_lock(&sl->lock);
361 if (!netif_running(dev)) {
362 spin_unlock(&sl->lock);
363 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
364 goto out;
365 }
366 if (sl->tty == NULL) {
367 spin_unlock(&sl->lock);
368 goto out;
369 }
370
371 netif_stop_queue(sl->dev);
372 slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
373 spin_unlock(&sl->lock);
374
375 out:
376 kfree_skb(skb);
377 return NETDEV_TX_OK;
378 }
379
380
381 /******************************************
382 * Routines looking at netdevice side.
383 ******************************************/
384
385 /* Netdevice UP -> DOWN routine */
slc_close(struct net_device * dev)386 static int slc_close(struct net_device *dev)
387 {
388 struct slcan *sl = netdev_priv(dev);
389
390 spin_lock_bh(&sl->lock);
391 if (sl->tty) {
392 /* TTY discipline is running. */
393 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
394 }
395 netif_stop_queue(dev);
396 sl->rcount = 0;
397 sl->xleft = 0;
398 spin_unlock_bh(&sl->lock);
399
400 return 0;
401 }
402
403 /* Netdevice DOWN -> UP routine */
slc_open(struct net_device * dev)404 static int slc_open(struct net_device *dev)
405 {
406 struct slcan *sl = netdev_priv(dev);
407
408 if (sl->tty == NULL)
409 return -ENODEV;
410
411 sl->flags &= (1 << SLF_INUSE);
412 netif_start_queue(dev);
413 return 0;
414 }
415
416 /* Hook the destructor so we can free slcan devs at the right point in time */
slc_free_netdev(struct net_device * dev)417 static void slc_free_netdev(struct net_device *dev)
418 {
419 int i = dev->base_addr;
420
421 slcan_devs[i] = NULL;
422 }
423
slcan_change_mtu(struct net_device * dev,int new_mtu)424 static int slcan_change_mtu(struct net_device *dev, int new_mtu)
425 {
426 return -EINVAL;
427 }
428
429 static const struct net_device_ops slc_netdev_ops = {
430 .ndo_open = slc_open,
431 .ndo_stop = slc_close,
432 .ndo_start_xmit = slc_xmit,
433 .ndo_change_mtu = slcan_change_mtu,
434 };
435
slc_setup(struct net_device * dev)436 static void slc_setup(struct net_device *dev)
437 {
438 dev->netdev_ops = &slc_netdev_ops;
439 dev->needs_free_netdev = true;
440 dev->priv_destructor = slc_free_netdev;
441
442 dev->hard_header_len = 0;
443 dev->addr_len = 0;
444 dev->tx_queue_len = 10;
445
446 dev->mtu = CAN_MTU;
447 dev->type = ARPHRD_CAN;
448
449 /* New-style flags. */
450 dev->flags = IFF_NOARP;
451 dev->features = NETIF_F_HW_CSUM;
452 }
453
454 /******************************************
455 Routines looking at TTY side.
456 ******************************************/
457
458 /*
459 * Handle the 'receiver data ready' interrupt.
460 * This function is called by the 'tty_io' module in the kernel when
461 * a block of SLCAN data has been received, which can now be decapsulated
462 * and sent on to some IP layer for further processing. This will not
463 * be re-entered while running but other ldisc functions may be called
464 * in parallel
465 */
466
slcan_receive_buf(struct tty_struct * tty,const unsigned char * cp,char * fp,int count)467 static void slcan_receive_buf(struct tty_struct *tty,
468 const unsigned char *cp, char *fp, int count)
469 {
470 struct slcan *sl = (struct slcan *) tty->disc_data;
471
472 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
473 return;
474
475 /* Read the characters out of the buffer */
476 while (count--) {
477 if (fp && *fp++) {
478 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
479 sl->dev->stats.rx_errors++;
480 cp++;
481 continue;
482 }
483 slcan_unesc(sl, *cp++);
484 }
485 }
486
487 /************************************
488 * slcan_open helper routines.
489 ************************************/
490
491 /* Collect hanged up channels */
slc_sync(void)492 static void slc_sync(void)
493 {
494 int i;
495 struct net_device *dev;
496 struct slcan *sl;
497
498 for (i = 0; i < maxdev; i++) {
499 dev = slcan_devs[i];
500 if (dev == NULL)
501 break;
502
503 sl = netdev_priv(dev);
504 if (sl->tty)
505 continue;
506 if (dev->flags & IFF_UP)
507 dev_close(dev);
508 }
509 }
510
511 /* Find a free SLCAN channel, and link in this `tty' line. */
slc_alloc(void)512 static struct slcan *slc_alloc(void)
513 {
514 int i;
515 char name[IFNAMSIZ];
516 struct net_device *dev = NULL;
517 struct slcan *sl;
518 int size;
519
520 for (i = 0; i < maxdev; i++) {
521 dev = slcan_devs[i];
522 if (dev == NULL)
523 break;
524
525 }
526
527 /* Sorry, too many, all slots in use */
528 if (i >= maxdev)
529 return NULL;
530
531 sprintf(name, "slcan%d", i);
532 size = ALIGN(sizeof(*sl), NETDEV_ALIGN) + sizeof(struct can_ml_priv);
533 dev = alloc_netdev(size, name, NET_NAME_UNKNOWN, slc_setup);
534 if (!dev)
535 return NULL;
536
537 dev->base_addr = i;
538 sl = netdev_priv(dev);
539 dev->ml_priv = (void *)sl + ALIGN(sizeof(*sl), NETDEV_ALIGN);
540
541 /* Initialize channel control data */
542 sl->magic = SLCAN_MAGIC;
543 sl->dev = dev;
544 spin_lock_init(&sl->lock);
545 INIT_WORK(&sl->tx_work, slcan_transmit);
546 slcan_devs[i] = dev;
547
548 return sl;
549 }
550
551 /*
552 * Open the high-level part of the SLCAN channel.
553 * This function is called by the TTY module when the
554 * SLCAN line discipline is called for. Because we are
555 * sure the tty line exists, we only have to link it to
556 * a free SLCAN channel...
557 *
558 * Called in process context serialized from other ldisc calls.
559 */
560
slcan_open(struct tty_struct * tty)561 static int slcan_open(struct tty_struct *tty)
562 {
563 struct slcan *sl;
564 int err;
565
566 if (!capable(CAP_NET_ADMIN))
567 return -EPERM;
568
569 if (tty->ops->write == NULL)
570 return -EOPNOTSUPP;
571
572 /* RTnetlink lock is misused here to serialize concurrent
573 opens of slcan channels. There are better ways, but it is
574 the simplest one.
575 */
576 rtnl_lock();
577
578 /* Collect hanged up channels. */
579 slc_sync();
580
581 sl = tty->disc_data;
582
583 err = -EEXIST;
584 /* First make sure we're not already connected. */
585 if (sl && sl->magic == SLCAN_MAGIC)
586 goto err_exit;
587
588 /* OK. Find a free SLCAN channel to use. */
589 err = -ENFILE;
590 sl = slc_alloc();
591 if (sl == NULL)
592 goto err_exit;
593
594 sl->tty = tty;
595 tty->disc_data = sl;
596
597 if (!test_bit(SLF_INUSE, &sl->flags)) {
598 /* Perform the low-level SLCAN initialization. */
599 sl->rcount = 0;
600 sl->xleft = 0;
601
602 set_bit(SLF_INUSE, &sl->flags);
603
604 err = register_netdevice(sl->dev);
605 if (err)
606 goto err_free_chan;
607 }
608
609 /* Done. We have linked the TTY line to a channel. */
610 rtnl_unlock();
611 tty->receive_room = 65536; /* We don't flow control */
612
613 /* TTY layer expects 0 on success */
614 return 0;
615
616 err_free_chan:
617 sl->tty = NULL;
618 tty->disc_data = NULL;
619 clear_bit(SLF_INUSE, &sl->flags);
620 free_netdev(sl->dev);
621
622 err_exit:
623 rtnl_unlock();
624
625 /* Count references from TTY module */
626 return err;
627 }
628
629 /*
630 * Close down a SLCAN channel.
631 * This means flushing out any pending queues, and then returning. This
632 * call is serialized against other ldisc functions.
633 *
634 * We also use this method for a hangup event.
635 */
636
slcan_close(struct tty_struct * tty)637 static void slcan_close(struct tty_struct *tty)
638 {
639 struct slcan *sl = (struct slcan *) tty->disc_data;
640
641 /* First make sure we're connected. */
642 if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
643 return;
644
645 spin_lock_bh(&sl->lock);
646 tty->disc_data = NULL;
647 sl->tty = NULL;
648 spin_unlock_bh(&sl->lock);
649
650 flush_work(&sl->tx_work);
651
652 /* Flush network side */
653 unregister_netdev(sl->dev);
654 /* This will complete via sl_free_netdev */
655 }
656
slcan_hangup(struct tty_struct * tty)657 static int slcan_hangup(struct tty_struct *tty)
658 {
659 slcan_close(tty);
660 return 0;
661 }
662
663 /* Perform I/O control on an active SLCAN channel. */
slcan_ioctl(struct tty_struct * tty,struct file * file,unsigned int cmd,unsigned long arg)664 static int slcan_ioctl(struct tty_struct *tty, struct file *file,
665 unsigned int cmd, unsigned long arg)
666 {
667 struct slcan *sl = (struct slcan *) tty->disc_data;
668 unsigned int tmp;
669
670 /* First make sure we're connected. */
671 if (!sl || sl->magic != SLCAN_MAGIC)
672 return -EINVAL;
673
674 switch (cmd) {
675 case SIOCGIFNAME:
676 tmp = strlen(sl->dev->name) + 1;
677 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
678 return -EFAULT;
679 return 0;
680
681 case SIOCSIFHWADDR:
682 return -EINVAL;
683
684 default:
685 return tty_mode_ioctl(tty, file, cmd, arg);
686 }
687 }
688
689 static struct tty_ldisc_ops slc_ldisc = {
690 .owner = THIS_MODULE,
691 .magic = TTY_LDISC_MAGIC,
692 .name = "slcan",
693 .open = slcan_open,
694 .close = slcan_close,
695 .hangup = slcan_hangup,
696 .ioctl = slcan_ioctl,
697 .receive_buf = slcan_receive_buf,
698 .write_wakeup = slcan_write_wakeup,
699 };
700
slcan_init(void)701 static int __init slcan_init(void)
702 {
703 int status;
704
705 if (maxdev < 4)
706 maxdev = 4; /* Sanity */
707
708 pr_info("slcan: serial line CAN interface driver\n");
709 pr_info("slcan: %d dynamic interface channels.\n", maxdev);
710
711 slcan_devs = kcalloc(maxdev, sizeof(struct net_device *), GFP_KERNEL);
712 if (!slcan_devs)
713 return -ENOMEM;
714
715 /* Fill in our line protocol discipline, and register it */
716 status = tty_register_ldisc(N_SLCAN, &slc_ldisc);
717 if (status) {
718 printk(KERN_ERR "slcan: can't register line discipline\n");
719 kfree(slcan_devs);
720 }
721 return status;
722 }
723
slcan_exit(void)724 static void __exit slcan_exit(void)
725 {
726 int i;
727 struct net_device *dev;
728 struct slcan *sl;
729 unsigned long timeout = jiffies + HZ;
730 int busy = 0;
731
732 if (slcan_devs == NULL)
733 return;
734
735 /* First of all: check for active disciplines and hangup them.
736 */
737 do {
738 if (busy)
739 msleep_interruptible(100);
740
741 busy = 0;
742 for (i = 0; i < maxdev; i++) {
743 dev = slcan_devs[i];
744 if (!dev)
745 continue;
746 sl = netdev_priv(dev);
747 spin_lock_bh(&sl->lock);
748 if (sl->tty) {
749 busy++;
750 tty_hangup(sl->tty);
751 }
752 spin_unlock_bh(&sl->lock);
753 }
754 } while (busy && time_before(jiffies, timeout));
755
756 /* FIXME: hangup is async so we should wait when doing this second
757 phase */
758
759 for (i = 0; i < maxdev; i++) {
760 dev = slcan_devs[i];
761 if (!dev)
762 continue;
763 slcan_devs[i] = NULL;
764
765 sl = netdev_priv(dev);
766 if (sl->tty) {
767 printk(KERN_ERR "%s: tty discipline still running\n",
768 dev->name);
769 }
770
771 unregister_netdev(dev);
772 }
773
774 kfree(slcan_devs);
775 slcan_devs = NULL;
776
777 i = tty_unregister_ldisc(N_SLCAN);
778 if (i)
779 printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i);
780 }
781
782 module_init(slcan_init);
783 module_exit(slcan_exit);
784
