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a1044e36 OH |
1 | /* |
2 | * slcan.c - serial line CAN interface driver (using tty line discipline) | |
3 | * | |
4 | * This file is derived from linux/drivers/net/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 | * Send feedback to <socketcan-users@lists.berlios.de> | |
39 | * | |
40 | */ | |
41 | ||
42 | #include <linux/module.h> | |
43 | #include <linux/moduleparam.h> | |
44 | ||
45 | #include <asm/system.h> | |
46 | #include <linux/uaccess.h> | |
47 | #include <linux/bitops.h> | |
48 | #include <linux/string.h> | |
49 | #include <linux/tty.h> | |
50 | #include <linux/errno.h> | |
51 | #include <linux/netdevice.h> | |
52 | #include <linux/skbuff.h> | |
53 | #include <linux/rtnetlink.h> | |
54 | #include <linux/if_arp.h> | |
55 | #include <linux/if_ether.h> | |
56 | #include <linux/delay.h> | |
57 | #include <linux/init.h> | |
58 | #include <linux/can.h> | |
59 | ||
60 | static __initdata const char banner[] = | |
61 | KERN_INFO "slcan: serial line CAN interface driver\n"; | |
62 | ||
63 | MODULE_ALIAS_LDISC(N_SLCAN); | |
64 | MODULE_DESCRIPTION("serial line CAN interface"); | |
65 | MODULE_LICENSE("GPL"); | |
66 | MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>"); | |
67 | ||
68 | #define SLCAN_MAGIC 0x53CA | |
69 | ||
70 | static int maxdev = 10; /* MAX number of SLCAN channels; | |
71 | This can be overridden with | |
72 | insmod slcan.ko maxdev=nnn */ | |
73 | module_param(maxdev, int, 0); | |
74 | MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces"); | |
75 | ||
76 | /* maximum rx buffer len: extended CAN frame with timestamp */ | |
77 | #define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1) | |
78 | ||
79 | struct slcan { | |
80 | int magic; | |
81 | ||
82 | /* Various fields. */ | |
83 | struct tty_struct *tty; /* ptr to TTY structure */ | |
84 | struct net_device *dev; /* easy for intr handling */ | |
85 | spinlock_t lock; | |
86 | ||
87 | /* These are pointers to the malloc()ed frame buffers. */ | |
88 | unsigned char rbuff[SLC_MTU]; /* receiver buffer */ | |
89 | int rcount; /* received chars counter */ | |
90 | unsigned char xbuff[SLC_MTU]; /* transmitter buffer */ | |
91 | unsigned char *xhead; /* pointer to next XMIT byte */ | |
92 | int xleft; /* bytes left in XMIT queue */ | |
93 | ||
94 | unsigned long flags; /* Flag values/ mode etc */ | |
95 | #define SLF_INUSE 0 /* Channel in use */ | |
96 | #define SLF_ERROR 1 /* Parity, etc. error */ | |
97 | ||
98 | unsigned char leased; | |
99 | dev_t line; | |
100 | pid_t pid; | |
101 | }; | |
102 | ||
103 | static struct net_device **slcan_devs; | |
104 | ||
105 | /************************************************************************ | |
106 | * SLCAN ENCAPSULATION FORMAT * | |
107 | ************************************************************************/ | |
108 | ||
109 | /* | |
110 | * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended | |
111 | * frame format) a data length code (can_dlc) which can be from 0 to 8 | |
112 | * and up to <can_dlc> data bytes as payload. | |
113 | * Additionally a CAN frame may become a remote transmission frame if the | |
114 | * RTR-bit is set. This causes another ECU to send a CAN frame with the | |
115 | * given can_id. | |
116 | * | |
117 | * The SLCAN ASCII representation of these different frame types is: | |
118 | * <type> <id> <dlc> <data>* | |
119 | * | |
120 | * Extended frames (29 bit) are defined by capital characters in the type. | |
121 | * RTR frames are defined as 'r' types - normal frames have 't' type: | |
122 | * t => 11 bit data frame | |
123 | * r => 11 bit RTR frame | |
124 | * T => 29 bit data frame | |
125 | * R => 29 bit RTR frame | |
126 | * | |
127 | * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64). | |
128 | * The <dlc> is a one byte ASCII number ('0' - '8') | |
129 | * The <data> section has at much ASCII Hex bytes as defined by the <dlc> | |
130 | * | |
131 | * Examples: | |
132 | * | |
133 | * t1230 : can_id 0x123, can_dlc 0, no data | |
134 | * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33 | |
135 | * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55 | |
136 | * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request | |
137 | * | |
138 | */ | |
139 | ||
140 | /************************************************************************ | |
141 | * STANDARD SLCAN DECAPSULATION * | |
142 | ************************************************************************/ | |
143 | ||
144 | static int asc2nibble(char c) | |
145 | { | |
146 | ||
147 | if ((c >= '0') && (c <= '9')) | |
148 | return c - '0'; | |
149 | ||
150 | if ((c >= 'A') && (c <= 'F')) | |
151 | return c - 'A' + 10; | |
152 | ||
153 | if ((c >= 'a') && (c <= 'f')) | |
154 | return c - 'a' + 10; | |
155 | ||
156 | return 16; /* error */ | |
157 | } | |
158 | ||
159 | /* Send one completely decapsulated can_frame to the network layer */ | |
160 | static void slc_bump(struct slcan *sl) | |
161 | { | |
162 | struct sk_buff *skb; | |
163 | struct can_frame cf; | |
164 | int i, dlc_pos, tmp; | |
165 | unsigned long ultmp; | |
166 | char cmd = sl->rbuff[0]; | |
167 | ||
168 | if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R')) | |
169 | return; | |
170 | ||
171 | if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */ | |
172 | dlc_pos = 4; /* dlc position tiiid */ | |
173 | else | |
174 | dlc_pos = 9; /* dlc position Tiiiiiiiid */ | |
175 | ||
176 | if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9'))) | |
177 | return; | |
178 | ||
179 | cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */ | |
180 | ||
181 | sl->rbuff[dlc_pos] = 0; /* terminate can_id string */ | |
182 | ||
183 | if (strict_strtoul(sl->rbuff+1, 16, &ultmp)) | |
184 | return; | |
185 | ||
186 | cf.can_id = ultmp; | |
187 | ||
188 | if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */ | |
189 | cf.can_id |= CAN_EFF_FLAG; | |
190 | ||
191 | if ((cmd | 0x20) == 'r') /* RTR frame */ | |
192 | cf.can_id |= CAN_RTR_FLAG; | |
193 | ||
194 | *(u64 *) (&cf.data) = 0; /* clear payload */ | |
195 | ||
196 | for (i = 0, dlc_pos++; i < cf.can_dlc; i++) { | |
197 | ||
198 | tmp = asc2nibble(sl->rbuff[dlc_pos++]); | |
199 | if (tmp > 0x0F) | |
200 | return; | |
201 | cf.data[i] = (tmp << 4); | |
202 | tmp = asc2nibble(sl->rbuff[dlc_pos++]); | |
203 | if (tmp > 0x0F) | |
204 | return; | |
205 | cf.data[i] |= tmp; | |
206 | } | |
207 | ||
208 | ||
209 | skb = dev_alloc_skb(sizeof(struct can_frame)); | |
210 | if (!skb) | |
211 | return; | |
212 | ||
213 | skb->dev = sl->dev; | |
214 | skb->protocol = htons(ETH_P_CAN); | |
215 | skb->pkt_type = PACKET_BROADCAST; | |
216 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
217 | memcpy(skb_put(skb, sizeof(struct can_frame)), | |
218 | &cf, sizeof(struct can_frame)); | |
219 | netif_rx(skb); | |
220 | ||
221 | sl->dev->stats.rx_packets++; | |
222 | sl->dev->stats.rx_bytes += cf.can_dlc; | |
223 | } | |
224 | ||
225 | /* parse tty input stream */ | |
226 | static void slcan_unesc(struct slcan *sl, unsigned char s) | |
227 | { | |
228 | ||
229 | if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */ | |
230 | if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && | |
231 | (sl->rcount > 4)) { | |
232 | slc_bump(sl); | |
233 | } | |
234 | sl->rcount = 0; | |
235 | } else { | |
236 | if (!test_bit(SLF_ERROR, &sl->flags)) { | |
237 | if (sl->rcount < SLC_MTU) { | |
238 | sl->rbuff[sl->rcount++] = s; | |
239 | return; | |
240 | } else { | |
241 | sl->dev->stats.rx_over_errors++; | |
242 | set_bit(SLF_ERROR, &sl->flags); | |
243 | } | |
244 | } | |
245 | } | |
246 | } | |
247 | ||
248 | /************************************************************************ | |
249 | * STANDARD SLCAN ENCAPSULATION * | |
250 | ************************************************************************/ | |
251 | ||
252 | /* Encapsulate one can_frame and stuff into a TTY queue. */ | |
253 | static void slc_encaps(struct slcan *sl, struct can_frame *cf) | |
254 | { | |
255 | int actual, idx, i; | |
256 | char cmd; | |
257 | ||
258 | if (cf->can_id & CAN_RTR_FLAG) | |
259 | cmd = 'R'; /* becomes 'r' in standard frame format */ | |
260 | else | |
261 | cmd = 'T'; /* becomes 't' in standard frame format */ | |
262 | ||
263 | if (cf->can_id & CAN_EFF_FLAG) | |
264 | sprintf(sl->xbuff, "%c%08X%d", cmd, | |
265 | cf->can_id & CAN_EFF_MASK, cf->can_dlc); | |
266 | else | |
267 | sprintf(sl->xbuff, "%c%03X%d", cmd | 0x20, | |
268 | cf->can_id & CAN_SFF_MASK, cf->can_dlc); | |
269 | ||
270 | idx = strlen(sl->xbuff); | |
271 | ||
272 | for (i = 0; i < cf->can_dlc; i++) | |
273 | sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]); | |
274 | ||
275 | strcat(sl->xbuff, "\r"); /* add terminating character */ | |
276 | ||
277 | /* Order of next two lines is *very* important. | |
278 | * When we are sending a little amount of data, | |
279 | * the transfer may be completed inside the ops->write() | |
280 | * routine, because it's running with interrupts enabled. | |
281 | * In this case we *never* got WRITE_WAKEUP event, | |
282 | * if we did not request it before write operation. | |
283 | * 14 Oct 1994 Dmitry Gorodchanin. | |
284 | */ | |
285 | set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); | |
286 | actual = sl->tty->ops->write(sl->tty, sl->xbuff, strlen(sl->xbuff)); | |
287 | sl->xleft = strlen(sl->xbuff) - actual; | |
288 | sl->xhead = sl->xbuff + actual; | |
289 | sl->dev->stats.tx_bytes += cf->can_dlc; | |
290 | } | |
291 | ||
292 | /* | |
293 | * Called by the driver when there's room for more data. If we have | |
294 | * more packets to send, we send them here. | |
295 | */ | |
296 | static void slcan_write_wakeup(struct tty_struct *tty) | |
297 | { | |
298 | int actual; | |
299 | struct slcan *sl = (struct slcan *) tty->disc_data; | |
300 | ||
301 | /* First make sure we're connected. */ | |
302 | if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) | |
303 | return; | |
304 | ||
305 | if (sl->xleft <= 0) { | |
306 | /* Now serial buffer is almost free & we can start | |
307 | * transmission of another packet */ | |
308 | sl->dev->stats.tx_packets++; | |
309 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
310 | netif_wake_queue(sl->dev); | |
311 | return; | |
312 | } | |
313 | ||
314 | actual = tty->ops->write(tty, sl->xhead, sl->xleft); | |
315 | sl->xleft -= actual; | |
316 | sl->xhead += actual; | |
317 | } | |
318 | ||
319 | /* Send a can_frame to a TTY queue. */ | |
320 | static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev) | |
321 | { | |
322 | struct slcan *sl = netdev_priv(dev); | |
323 | ||
324 | if (skb->len != sizeof(struct can_frame)) | |
325 | goto out; | |
326 | ||
327 | spin_lock(&sl->lock); | |
328 | if (!netif_running(dev)) { | |
329 | spin_unlock(&sl->lock); | |
330 | printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name); | |
331 | goto out; | |
332 | } | |
333 | if (sl->tty == NULL) { | |
334 | spin_unlock(&sl->lock); | |
335 | goto out; | |
336 | } | |
337 | ||
338 | netif_stop_queue(sl->dev); | |
339 | slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */ | |
340 | spin_unlock(&sl->lock); | |
341 | ||
342 | out: | |
343 | kfree_skb(skb); | |
344 | return NETDEV_TX_OK; | |
345 | } | |
346 | ||
347 | ||
348 | /****************************************** | |
349 | * Routines looking at netdevice side. | |
350 | ******************************************/ | |
351 | ||
352 | /* Netdevice UP -> DOWN routine */ | |
353 | static int slc_close(struct net_device *dev) | |
354 | { | |
355 | struct slcan *sl = netdev_priv(dev); | |
356 | ||
357 | spin_lock_bh(&sl->lock); | |
358 | if (sl->tty) { | |
359 | /* TTY discipline is running. */ | |
360 | clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); | |
361 | } | |
362 | netif_stop_queue(dev); | |
363 | sl->rcount = 0; | |
364 | sl->xleft = 0; | |
365 | spin_unlock_bh(&sl->lock); | |
366 | ||
367 | return 0; | |
368 | } | |
369 | ||
370 | /* Netdevice DOWN -> UP routine */ | |
371 | static int slc_open(struct net_device *dev) | |
372 | { | |
373 | struct slcan *sl = netdev_priv(dev); | |
374 | ||
375 | if (sl->tty == NULL) | |
376 | return -ENODEV; | |
377 | ||
378 | sl->flags &= (1 << SLF_INUSE); | |
379 | netif_start_queue(dev); | |
380 | return 0; | |
381 | } | |
382 | ||
383 | /* Hook the destructor so we can free slcan devs at the right point in time */ | |
384 | static void slc_free_netdev(struct net_device *dev) | |
385 | { | |
386 | int i = dev->base_addr; | |
387 | free_netdev(dev); | |
388 | slcan_devs[i] = NULL; | |
389 | } | |
390 | ||
391 | static const struct net_device_ops slc_netdev_ops = { | |
392 | .ndo_open = slc_open, | |
393 | .ndo_stop = slc_close, | |
394 | .ndo_start_xmit = slc_xmit, | |
395 | }; | |
396 | ||
397 | static void slc_setup(struct net_device *dev) | |
398 | { | |
399 | dev->netdev_ops = &slc_netdev_ops; | |
400 | dev->destructor = slc_free_netdev; | |
401 | ||
402 | dev->hard_header_len = 0; | |
403 | dev->addr_len = 0; | |
404 | dev->tx_queue_len = 10; | |
405 | ||
406 | dev->mtu = sizeof(struct can_frame); | |
407 | dev->type = ARPHRD_CAN; | |
408 | ||
409 | /* New-style flags. */ | |
410 | dev->flags = IFF_NOARP; | |
411 | dev->features = NETIF_F_NO_CSUM; | |
412 | } | |
413 | ||
414 | /****************************************** | |
415 | Routines looking at TTY side. | |
416 | ******************************************/ | |
417 | ||
418 | /* | |
419 | * Handle the 'receiver data ready' interrupt. | |
420 | * This function is called by the 'tty_io' module in the kernel when | |
421 | * a block of SLCAN data has been received, which can now be decapsulated | |
422 | * and sent on to some IP layer for further processing. This will not | |
423 | * be re-entered while running but other ldisc functions may be called | |
424 | * in parallel | |
425 | */ | |
426 | ||
427 | static void slcan_receive_buf(struct tty_struct *tty, | |
428 | const unsigned char *cp, char *fp, int count) | |
429 | { | |
430 | struct slcan *sl = (struct slcan *) tty->disc_data; | |
431 | ||
432 | if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) | |
433 | return; | |
434 | ||
435 | /* Read the characters out of the buffer */ | |
436 | while (count--) { | |
437 | if (fp && *fp++) { | |
438 | if (!test_and_set_bit(SLF_ERROR, &sl->flags)) | |
439 | sl->dev->stats.rx_errors++; | |
440 | cp++; | |
441 | continue; | |
442 | } | |
443 | slcan_unesc(sl, *cp++); | |
444 | } | |
445 | } | |
446 | ||
447 | /************************************ | |
448 | * slcan_open helper routines. | |
449 | ************************************/ | |
450 | ||
451 | /* Collect hanged up channels */ | |
452 | static void slc_sync(void) | |
453 | { | |
454 | int i; | |
455 | struct net_device *dev; | |
456 | struct slcan *sl; | |
457 | ||
458 | for (i = 0; i < maxdev; i++) { | |
459 | dev = slcan_devs[i]; | |
460 | if (dev == NULL) | |
461 | break; | |
462 | ||
463 | sl = netdev_priv(dev); | |
464 | if (sl->tty || sl->leased) | |
465 | continue; | |
466 | if (dev->flags & IFF_UP) | |
467 | dev_close(dev); | |
468 | } | |
469 | } | |
470 | ||
471 | /* Find a free SLCAN channel, and link in this `tty' line. */ | |
472 | static struct slcan *slc_alloc(dev_t line) | |
473 | { | |
474 | int i; | |
475 | struct net_device *dev = NULL; | |
476 | struct slcan *sl; | |
477 | ||
478 | if (slcan_devs == NULL) | |
479 | return NULL; /* Master array missing ! */ | |
480 | ||
481 | for (i = 0; i < maxdev; i++) { | |
482 | dev = slcan_devs[i]; | |
483 | if (dev == NULL) | |
484 | break; | |
485 | ||
486 | } | |
487 | ||
488 | /* Sorry, too many, all slots in use */ | |
489 | if (i >= maxdev) | |
490 | return NULL; | |
491 | ||
492 | if (dev) { | |
493 | sl = netdev_priv(dev); | |
494 | if (test_bit(SLF_INUSE, &sl->flags)) { | |
495 | unregister_netdevice(dev); | |
496 | dev = NULL; | |
497 | slcan_devs[i] = NULL; | |
498 | } | |
499 | } | |
500 | ||
501 | if (!dev) { | |
502 | char name[IFNAMSIZ]; | |
503 | sprintf(name, "slcan%d", i); | |
504 | ||
505 | dev = alloc_netdev(sizeof(*sl), name, slc_setup); | |
506 | if (!dev) | |
507 | return NULL; | |
508 | dev->base_addr = i; | |
509 | } | |
510 | ||
511 | sl = netdev_priv(dev); | |
512 | ||
513 | /* Initialize channel control data */ | |
514 | sl->magic = SLCAN_MAGIC; | |
515 | sl->dev = dev; | |
516 | spin_lock_init(&sl->lock); | |
517 | slcan_devs[i] = dev; | |
518 | ||
519 | return sl; | |
520 | } | |
521 | ||
522 | /* | |
523 | * Open the high-level part of the SLCAN channel. | |
524 | * This function is called by the TTY module when the | |
525 | * SLCAN line discipline is called for. Because we are | |
526 | * sure the tty line exists, we only have to link it to | |
527 | * a free SLCAN channel... | |
528 | * | |
529 | * Called in process context serialized from other ldisc calls. | |
530 | */ | |
531 | ||
532 | static int slcan_open(struct tty_struct *tty) | |
533 | { | |
534 | struct slcan *sl; | |
535 | int err; | |
536 | ||
537 | if (!capable(CAP_NET_ADMIN)) | |
538 | return -EPERM; | |
539 | ||
540 | if (tty->ops->write == NULL) | |
541 | return -EOPNOTSUPP; | |
542 | ||
543 | /* RTnetlink lock is misused here to serialize concurrent | |
544 | opens of slcan channels. There are better ways, but it is | |
545 | the simplest one. | |
546 | */ | |
547 | rtnl_lock(); | |
548 | ||
549 | /* Collect hanged up channels. */ | |
550 | slc_sync(); | |
551 | ||
552 | sl = tty->disc_data; | |
553 | ||
554 | err = -EEXIST; | |
555 | /* First make sure we're not already connected. */ | |
556 | if (sl && sl->magic == SLCAN_MAGIC) | |
557 | goto err_exit; | |
558 | ||
559 | /* OK. Find a free SLCAN channel to use. */ | |
560 | err = -ENFILE; | |
561 | sl = slc_alloc(tty_devnum(tty)); | |
562 | if (sl == NULL) | |
563 | goto err_exit; | |
564 | ||
565 | sl->tty = tty; | |
566 | tty->disc_data = sl; | |
567 | sl->line = tty_devnum(tty); | |
568 | sl->pid = current->pid; | |
569 | ||
570 | if (!test_bit(SLF_INUSE, &sl->flags)) { | |
571 | /* Perform the low-level SLCAN initialization. */ | |
572 | sl->rcount = 0; | |
573 | sl->xleft = 0; | |
574 | ||
575 | set_bit(SLF_INUSE, &sl->flags); | |
576 | ||
577 | err = register_netdevice(sl->dev); | |
578 | if (err) | |
579 | goto err_free_chan; | |
580 | } | |
581 | ||
582 | /* Done. We have linked the TTY line to a channel. */ | |
583 | rtnl_unlock(); | |
584 | tty->receive_room = 65536; /* We don't flow control */ | |
585 | return sl->dev->base_addr; | |
586 | ||
587 | err_free_chan: | |
588 | sl->tty = NULL; | |
589 | tty->disc_data = NULL; | |
590 | clear_bit(SLF_INUSE, &sl->flags); | |
591 | ||
592 | err_exit: | |
593 | rtnl_unlock(); | |
594 | ||
595 | /* Count references from TTY module */ | |
596 | return err; | |
597 | } | |
598 | ||
599 | /* | |
600 | * Close down a SLCAN channel. | |
601 | * This means flushing out any pending queues, and then returning. This | |
602 | * call is serialized against other ldisc functions. | |
603 | * | |
604 | * We also use this method for a hangup event. | |
605 | */ | |
606 | ||
607 | static void slcan_close(struct tty_struct *tty) | |
608 | { | |
609 | struct slcan *sl = (struct slcan *) tty->disc_data; | |
610 | ||
611 | /* First make sure we're connected. */ | |
612 | if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty) | |
613 | return; | |
614 | ||
615 | tty->disc_data = NULL; | |
616 | sl->tty = NULL; | |
617 | if (!sl->leased) | |
618 | sl->line = 0; | |
619 | ||
620 | /* Flush network side */ | |
621 | unregister_netdev(sl->dev); | |
622 | /* This will complete via sl_free_netdev */ | |
623 | } | |
624 | ||
625 | static int slcan_hangup(struct tty_struct *tty) | |
626 | { | |
627 | slcan_close(tty); | |
628 | return 0; | |
629 | } | |
630 | ||
631 | /* Perform I/O control on an active SLCAN channel. */ | |
632 | static int slcan_ioctl(struct tty_struct *tty, struct file *file, | |
633 | unsigned int cmd, unsigned long arg) | |
634 | { | |
635 | struct slcan *sl = (struct slcan *) tty->disc_data; | |
636 | unsigned int tmp; | |
637 | ||
638 | /* First make sure we're connected. */ | |
639 | if (!sl || sl->magic != SLCAN_MAGIC) | |
640 | return -EINVAL; | |
641 | ||
642 | switch (cmd) { | |
643 | case SIOCGIFNAME: | |
644 | tmp = strlen(sl->dev->name) + 1; | |
645 | if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) | |
646 | return -EFAULT; | |
647 | return 0; | |
648 | ||
649 | case SIOCSIFHWADDR: | |
650 | return -EINVAL; | |
651 | ||
652 | default: | |
653 | return tty_mode_ioctl(tty, file, cmd, arg); | |
654 | } | |
655 | } | |
656 | ||
657 | static struct tty_ldisc_ops slc_ldisc = { | |
658 | .owner = THIS_MODULE, | |
659 | .magic = TTY_LDISC_MAGIC, | |
660 | .name = "slcan", | |
661 | .open = slcan_open, | |
662 | .close = slcan_close, | |
663 | .hangup = slcan_hangup, | |
664 | .ioctl = slcan_ioctl, | |
665 | .receive_buf = slcan_receive_buf, | |
666 | .write_wakeup = slcan_write_wakeup, | |
667 | }; | |
668 | ||
669 | static int __init slcan_init(void) | |
670 | { | |
671 | int status; | |
672 | ||
673 | if (maxdev < 4) | |
674 | maxdev = 4; /* Sanity */ | |
675 | ||
676 | printk(banner); | |
677 | printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev); | |
678 | ||
679 | slcan_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL); | |
680 | if (!slcan_devs) { | |
681 | printk(KERN_ERR "slcan: can't allocate slcan device array!\n"); | |
682 | return -ENOMEM; | |
683 | } | |
684 | ||
685 | /* Fill in our line protocol discipline, and register it */ | |
686 | status = tty_register_ldisc(N_SLCAN, &slc_ldisc); | |
687 | if (status) { | |
688 | printk(KERN_ERR "slcan: can't register line discipline\n"); | |
689 | kfree(slcan_devs); | |
690 | } | |
691 | return status; | |
692 | } | |
693 | ||
694 | static void __exit slcan_exit(void) | |
695 | { | |
696 | int i; | |
697 | struct net_device *dev; | |
698 | struct slcan *sl; | |
699 | unsigned long timeout = jiffies + HZ; | |
700 | int busy = 0; | |
701 | ||
702 | if (slcan_devs == NULL) | |
703 | return; | |
704 | ||
705 | /* First of all: check for active disciplines and hangup them. | |
706 | */ | |
707 | do { | |
708 | if (busy) | |
709 | msleep_interruptible(100); | |
710 | ||
711 | busy = 0; | |
712 | for (i = 0; i < maxdev; i++) { | |
713 | dev = slcan_devs[i]; | |
714 | if (!dev) | |
715 | continue; | |
716 | sl = netdev_priv(dev); | |
717 | spin_lock_bh(&sl->lock); | |
718 | if (sl->tty) { | |
719 | busy++; | |
720 | tty_hangup(sl->tty); | |
721 | } | |
722 | spin_unlock_bh(&sl->lock); | |
723 | } | |
724 | } while (busy && time_before(jiffies, timeout)); | |
725 | ||
726 | /* FIXME: hangup is async so we should wait when doing this second | |
727 | phase */ | |
728 | ||
729 | for (i = 0; i < maxdev; i++) { | |
730 | dev = slcan_devs[i]; | |
731 | if (!dev) | |
732 | continue; | |
733 | slcan_devs[i] = NULL; | |
734 | ||
735 | sl = netdev_priv(dev); | |
736 | if (sl->tty) { | |
737 | printk(KERN_ERR "%s: tty discipline still running\n", | |
738 | dev->name); | |
739 | /* Intentionally leak the control block. */ | |
740 | dev->destructor = NULL; | |
741 | } | |
742 | ||
743 | unregister_netdev(dev); | |
744 | } | |
745 | ||
746 | kfree(slcan_devs); | |
747 | slcan_devs = NULL; | |
748 | ||
749 | i = tty_unregister_ldisc(N_SLCAN); | |
750 | if (i) | |
751 | printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i); | |
752 | } | |
753 | ||
754 | module_init(slcan_init); | |
755 | module_exit(slcan_exit); |