Commit | Line | Data |
---|---|---|
a1044e36 OH |
1 | /* |
2 | * slcan.c - serial line CAN interface driver (using tty line discipline) | |
3 | * | |
3396c782 | 4 | * This file is derived from linux/drivers/net/slip/slip.c |
a1044e36 OH |
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 | * | |
a1044e36 OH |
38 | */ |
39 | ||
40 | #include <linux/module.h> | |
41 | #include <linux/moduleparam.h> | |
42 | ||
a1044e36 OH |
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> | |
84b3cdc3 | 53 | #include <linux/sched.h> |
a1044e36 OH |
54 | #include <linux/delay.h> |
55 | #include <linux/init.h> | |
81fc70d8 | 56 | #include <linux/kernel.h> |
a1044e36 | 57 | #include <linux/can.h> |
156c2bb9 | 58 | #include <linux/can/skb.h> |
a1044e36 | 59 | |
c477ebd8 | 60 | static __initconst const char banner[] = |
a1044e36 OH |
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 | ||
87397fe1 AN |
79 | #define SLC_CMD_LEN 1 |
80 | #define SLC_SFF_ID_LEN 3 | |
81 | #define SLC_EFF_ID_LEN 8 | |
82 | ||
a1044e36 OH |
83 | struct slcan { |
84 | int magic; | |
85 | ||
86 | /* Various fields. */ | |
87 | struct tty_struct *tty; /* ptr to TTY structure */ | |
88 | struct net_device *dev; /* easy for intr handling */ | |
89 | spinlock_t lock; | |
90 | ||
91 | /* These are pointers to the malloc()ed frame buffers. */ | |
92 | unsigned char rbuff[SLC_MTU]; /* receiver buffer */ | |
93 | int rcount; /* received chars counter */ | |
94 | unsigned char xbuff[SLC_MTU]; /* transmitter buffer */ | |
95 | unsigned char *xhead; /* pointer to next XMIT byte */ | |
96 | int xleft; /* bytes left in XMIT queue */ | |
97 | ||
98 | unsigned long flags; /* Flag values/ mode etc */ | |
99 | #define SLF_INUSE 0 /* Channel in use */ | |
100 | #define SLF_ERROR 1 /* Parity, etc. error */ | |
a1044e36 OH |
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 | ||
a1044e36 OH |
144 | /* Send one completely decapsulated can_frame to the network layer */ |
145 | static void slc_bump(struct slcan *sl) | |
146 | { | |
147 | struct sk_buff *skb; | |
148 | struct can_frame cf; | |
87397fe1 AN |
149 | int i, tmp; |
150 | u32 tmpid; | |
151 | char *cmd = sl->rbuff; | |
152 | ||
153 | cf.can_id = 0; | |
154 | ||
155 | switch (*cmd) { | |
156 | case 'r': | |
157 | cf.can_id = CAN_RTR_FLAG; | |
158 | /* fallthrough */ | |
159 | case 't': | |
160 | /* store dlc ASCII value and terminate SFF CAN ID string */ | |
161 | cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN]; | |
162 | sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN] = 0; | |
163 | /* point to payload data behind the dlc */ | |
164 | cmd += SLC_CMD_LEN + SLC_SFF_ID_LEN + 1; | |
165 | break; | |
166 | case 'R': | |
167 | cf.can_id = CAN_RTR_FLAG; | |
168 | /* fallthrough */ | |
169 | case 'T': | |
170 | cf.can_id |= CAN_EFF_FLAG; | |
171 | /* store dlc ASCII value and terminate EFF CAN ID string */ | |
172 | cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN]; | |
173 | sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN] = 0; | |
174 | /* point to payload data behind the dlc */ | |
175 | cmd += SLC_CMD_LEN + SLC_EFF_ID_LEN + 1; | |
176 | break; | |
177 | default: | |
a1044e36 | 178 | return; |
87397fe1 | 179 | } |
a1044e36 | 180 | |
87397fe1 | 181 | if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid)) |
a1044e36 OH |
182 | return; |
183 | ||
87397fe1 | 184 | cf.can_id |= tmpid; |
a1044e36 | 185 | |
87397fe1 AN |
186 | /* get can_dlc from sanitized ASCII value */ |
187 | if (cf.can_dlc >= '0' && cf.can_dlc < '9') | |
188 | cf.can_dlc -= '0'; | |
189 | else | |
a1044e36 OH |
190 | return; |
191 | ||
a1044e36 OH |
192 | *(u64 *) (&cf.data) = 0; /* clear payload */ |
193 | ||
87397fe1 AN |
194 | /* RTR frames may have a dlc > 0 but they never have any data bytes */ |
195 | if (!(cf.can_id & CAN_RTR_FLAG)) { | |
196 | for (i = 0; i < cf.can_dlc; i++) { | |
197 | tmp = hex_to_bin(*cmd++); | |
198 | if (tmp < 0) | |
199 | return; | |
200 | cf.data[i] = (tmp << 4); | |
201 | tmp = hex_to_bin(*cmd++); | |
202 | if (tmp < 0) | |
203 | return; | |
204 | cf.data[i] |= tmp; | |
205 | } | |
a1044e36 OH |
206 | } |
207 | ||
156c2bb9 OH |
208 | skb = dev_alloc_skb(sizeof(struct can_frame) + |
209 | sizeof(struct can_skb_priv)); | |
a1044e36 OH |
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; | |
156c2bb9 | 217 | |
2bf3440d OH |
218 | can_skb_reserve(skb); |
219 | can_skb_prv(skb)->ifindex = sl->dev->ifindex; | |
156c2bb9 | 220 | |
a1044e36 OH |
221 | memcpy(skb_put(skb, sizeof(struct can_frame)), |
222 | &cf, sizeof(struct can_frame)); | |
174c95d2 | 223 | netif_rx_ni(skb); |
a1044e36 OH |
224 | |
225 | sl->dev->stats.rx_packets++; | |
226 | sl->dev->stats.rx_bytes += cf.can_dlc; | |
227 | } | |
228 | ||
229 | /* parse tty input stream */ | |
230 | static void slcan_unesc(struct slcan *sl, unsigned char s) | |
231 | { | |
a1044e36 OH |
232 | if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */ |
233 | if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && | |
234 | (sl->rcount > 4)) { | |
235 | slc_bump(sl); | |
236 | } | |
237 | sl->rcount = 0; | |
238 | } else { | |
239 | if (!test_bit(SLF_ERROR, &sl->flags)) { | |
240 | if (sl->rcount < SLC_MTU) { | |
241 | sl->rbuff[sl->rcount++] = s; | |
242 | return; | |
243 | } else { | |
244 | sl->dev->stats.rx_over_errors++; | |
245 | set_bit(SLF_ERROR, &sl->flags); | |
246 | } | |
247 | } | |
248 | } | |
249 | } | |
250 | ||
251 | /************************************************************************ | |
252 | * STANDARD SLCAN ENCAPSULATION * | |
253 | ************************************************************************/ | |
254 | ||
255 | /* Encapsulate one can_frame and stuff into a TTY queue. */ | |
256 | static void slc_encaps(struct slcan *sl, struct can_frame *cf) | |
257 | { | |
87397fe1 AN |
258 | int actual, i; |
259 | unsigned char *pos; | |
260 | unsigned char *endpos; | |
261 | canid_t id = cf->can_id; | |
262 | ||
263 | pos = sl->xbuff; | |
a1044e36 OH |
264 | |
265 | if (cf->can_id & CAN_RTR_FLAG) | |
87397fe1 | 266 | *pos = 'R'; /* becomes 'r' in standard frame format (SFF) */ |
a1044e36 | 267 | else |
87397fe1 | 268 | *pos = 'T'; /* becomes 't' in standard frame format (SSF) */ |
a1044e36 | 269 | |
87397fe1 AN |
270 | /* determine number of chars for the CAN-identifier */ |
271 | if (cf->can_id & CAN_EFF_FLAG) { | |
272 | id &= CAN_EFF_MASK; | |
273 | endpos = pos + SLC_EFF_ID_LEN; | |
274 | } else { | |
275 | *pos |= 0x20; /* convert R/T to lower case for SFF */ | |
276 | id &= CAN_SFF_MASK; | |
277 | endpos = pos + SLC_SFF_ID_LEN; | |
278 | } | |
279 | ||
280 | /* build 3 (SFF) or 8 (EFF) digit CAN identifier */ | |
281 | pos++; | |
282 | while (endpos >= pos) { | |
283 | *endpos-- = hex_asc_upper[id & 0xf]; | |
284 | id >>= 4; | |
285 | } | |
286 | ||
287 | pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN; | |
a1044e36 | 288 | |
87397fe1 | 289 | *pos++ = cf->can_dlc + '0'; |
a1044e36 | 290 | |
87397fe1 AN |
291 | /* RTR frames may have a dlc > 0 but they never have any data bytes */ |
292 | if (!(cf->can_id & CAN_RTR_FLAG)) { | |
293 | for (i = 0; i < cf->can_dlc; i++) | |
294 | pos = hex_byte_pack_upper(pos, cf->data[i]); | |
295 | } | |
a1044e36 | 296 | |
87397fe1 | 297 | *pos++ = '\r'; |
a1044e36 OH |
298 | |
299 | /* Order of next two lines is *very* important. | |
300 | * When we are sending a little amount of data, | |
301 | * the transfer may be completed inside the ops->write() | |
302 | * routine, because it's running with interrupts enabled. | |
303 | * In this case we *never* got WRITE_WAKEUP event, | |
304 | * if we did not request it before write operation. | |
305 | * 14 Oct 1994 Dmitry Gorodchanin. | |
306 | */ | |
307 | set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); | |
87397fe1 AN |
308 | actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff); |
309 | sl->xleft = (pos - sl->xbuff) - actual; | |
a1044e36 OH |
310 | sl->xhead = sl->xbuff + actual; |
311 | sl->dev->stats.tx_bytes += cf->can_dlc; | |
312 | } | |
313 | ||
314 | /* | |
315 | * Called by the driver when there's room for more data. If we have | |
316 | * more packets to send, we send them here. | |
317 | */ | |
318 | static void slcan_write_wakeup(struct tty_struct *tty) | |
319 | { | |
320 | int actual; | |
321 | struct slcan *sl = (struct slcan *) tty->disc_data; | |
322 | ||
323 | /* First make sure we're connected. */ | |
324 | if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) | |
325 | return; | |
326 | ||
cc9fa74e | 327 | spin_lock(&sl->lock); |
a1044e36 OH |
328 | if (sl->xleft <= 0) { |
329 | /* Now serial buffer is almost free & we can start | |
330 | * transmission of another packet */ | |
331 | sl->dev->stats.tx_packets++; | |
332 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
cc9fa74e | 333 | spin_unlock(&sl->lock); |
a1044e36 OH |
334 | netif_wake_queue(sl->dev); |
335 | return; | |
336 | } | |
337 | ||
338 | actual = tty->ops->write(tty, sl->xhead, sl->xleft); | |
339 | sl->xleft -= actual; | |
340 | sl->xhead += actual; | |
cc9fa74e | 341 | spin_unlock(&sl->lock); |
a1044e36 OH |
342 | } |
343 | ||
344 | /* Send a can_frame to a TTY queue. */ | |
345 | static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev) | |
346 | { | |
347 | struct slcan *sl = netdev_priv(dev); | |
348 | ||
349 | if (skb->len != sizeof(struct can_frame)) | |
350 | goto out; | |
351 | ||
352 | spin_lock(&sl->lock); | |
353 | if (!netif_running(dev)) { | |
354 | spin_unlock(&sl->lock); | |
355 | printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name); | |
356 | goto out; | |
357 | } | |
358 | if (sl->tty == NULL) { | |
359 | spin_unlock(&sl->lock); | |
360 | goto out; | |
361 | } | |
362 | ||
363 | netif_stop_queue(sl->dev); | |
364 | slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */ | |
365 | spin_unlock(&sl->lock); | |
366 | ||
367 | out: | |
368 | kfree_skb(skb); | |
369 | return NETDEV_TX_OK; | |
370 | } | |
371 | ||
372 | ||
373 | /****************************************** | |
374 | * Routines looking at netdevice side. | |
375 | ******************************************/ | |
376 | ||
377 | /* Netdevice UP -> DOWN routine */ | |
378 | static int slc_close(struct net_device *dev) | |
379 | { | |
380 | struct slcan *sl = netdev_priv(dev); | |
381 | ||
382 | spin_lock_bh(&sl->lock); | |
383 | if (sl->tty) { | |
384 | /* TTY discipline is running. */ | |
385 | clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); | |
386 | } | |
387 | netif_stop_queue(dev); | |
388 | sl->rcount = 0; | |
389 | sl->xleft = 0; | |
390 | spin_unlock_bh(&sl->lock); | |
391 | ||
392 | return 0; | |
393 | } | |
394 | ||
395 | /* Netdevice DOWN -> UP routine */ | |
396 | static int slc_open(struct net_device *dev) | |
397 | { | |
398 | struct slcan *sl = netdev_priv(dev); | |
399 | ||
400 | if (sl->tty == NULL) | |
401 | return -ENODEV; | |
402 | ||
403 | sl->flags &= (1 << SLF_INUSE); | |
404 | netif_start_queue(dev); | |
405 | return 0; | |
406 | } | |
407 | ||
408 | /* Hook the destructor so we can free slcan devs at the right point in time */ | |
409 | static void slc_free_netdev(struct net_device *dev) | |
410 | { | |
411 | int i = dev->base_addr; | |
412 | free_netdev(dev); | |
413 | slcan_devs[i] = NULL; | |
414 | } | |
415 | ||
416 | static const struct net_device_ops slc_netdev_ops = { | |
417 | .ndo_open = slc_open, | |
418 | .ndo_stop = slc_close, | |
419 | .ndo_start_xmit = slc_xmit, | |
420 | }; | |
421 | ||
422 | static void slc_setup(struct net_device *dev) | |
423 | { | |
424 | dev->netdev_ops = &slc_netdev_ops; | |
425 | dev->destructor = slc_free_netdev; | |
426 | ||
427 | dev->hard_header_len = 0; | |
428 | dev->addr_len = 0; | |
429 | dev->tx_queue_len = 10; | |
430 | ||
431 | dev->mtu = sizeof(struct can_frame); | |
432 | dev->type = ARPHRD_CAN; | |
433 | ||
434 | /* New-style flags. */ | |
435 | dev->flags = IFF_NOARP; | |
34324dc2 | 436 | dev->features = NETIF_F_HW_CSUM; |
a1044e36 OH |
437 | } |
438 | ||
439 | /****************************************** | |
440 | Routines looking at TTY side. | |
441 | ******************************************/ | |
442 | ||
443 | /* | |
444 | * Handle the 'receiver data ready' interrupt. | |
445 | * This function is called by the 'tty_io' module in the kernel when | |
446 | * a block of SLCAN data has been received, which can now be decapsulated | |
447 | * and sent on to some IP layer for further processing. This will not | |
448 | * be re-entered while running but other ldisc functions may be called | |
449 | * in parallel | |
450 | */ | |
451 | ||
55db4c64 | 452 | static void slcan_receive_buf(struct tty_struct *tty, |
a1044e36 OH |
453 | const unsigned char *cp, char *fp, int count) |
454 | { | |
455 | struct slcan *sl = (struct slcan *) tty->disc_data; | |
456 | ||
457 | if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) | |
55db4c64 | 458 | return; |
a1044e36 OH |
459 | |
460 | /* Read the characters out of the buffer */ | |
55db4c64 | 461 | while (count--) { |
a1044e36 OH |
462 | if (fp && *fp++) { |
463 | if (!test_and_set_bit(SLF_ERROR, &sl->flags)) | |
464 | sl->dev->stats.rx_errors++; | |
465 | cp++; | |
466 | continue; | |
467 | } | |
468 | slcan_unesc(sl, *cp++); | |
469 | } | |
470 | } | |
471 | ||
472 | /************************************ | |
473 | * slcan_open helper routines. | |
474 | ************************************/ | |
475 | ||
476 | /* Collect hanged up channels */ | |
477 | static void slc_sync(void) | |
478 | { | |
479 | int i; | |
480 | struct net_device *dev; | |
481 | struct slcan *sl; | |
482 | ||
483 | for (i = 0; i < maxdev; i++) { | |
484 | dev = slcan_devs[i]; | |
485 | if (dev == NULL) | |
486 | break; | |
487 | ||
488 | sl = netdev_priv(dev); | |
7ad711b4 | 489 | if (sl->tty) |
a1044e36 OH |
490 | continue; |
491 | if (dev->flags & IFF_UP) | |
492 | dev_close(dev); | |
493 | } | |
494 | } | |
495 | ||
496 | /* Find a free SLCAN channel, and link in this `tty' line. */ | |
497 | static struct slcan *slc_alloc(dev_t line) | |
498 | { | |
499 | int i; | |
2af4ba85 | 500 | char name[IFNAMSIZ]; |
a1044e36 OH |
501 | struct net_device *dev = NULL; |
502 | struct slcan *sl; | |
503 | ||
a1044e36 OH |
504 | for (i = 0; i < maxdev; i++) { |
505 | dev = slcan_devs[i]; | |
506 | if (dev == NULL) | |
507 | break; | |
508 | ||
509 | } | |
510 | ||
511 | /* Sorry, too many, all slots in use */ | |
512 | if (i >= maxdev) | |
513 | return NULL; | |
514 | ||
2af4ba85 OH |
515 | sprintf(name, "slcan%d", i); |
516 | dev = alloc_netdev(sizeof(*sl), name, slc_setup); | |
517 | if (!dev) | |
518 | return NULL; | |
a1044e36 | 519 | |
2af4ba85 | 520 | dev->base_addr = i; |
a1044e36 OH |
521 | sl = netdev_priv(dev); |
522 | ||
523 | /* Initialize channel control data */ | |
524 | sl->magic = SLCAN_MAGIC; | |
525 | sl->dev = dev; | |
526 | spin_lock_init(&sl->lock); | |
527 | slcan_devs[i] = dev; | |
528 | ||
529 | return sl; | |
530 | } | |
531 | ||
532 | /* | |
533 | * Open the high-level part of the SLCAN channel. | |
534 | * This function is called by the TTY module when the | |
535 | * SLCAN line discipline is called for. Because we are | |
536 | * sure the tty line exists, we only have to link it to | |
537 | * a free SLCAN channel... | |
538 | * | |
539 | * Called in process context serialized from other ldisc calls. | |
540 | */ | |
541 | ||
542 | static int slcan_open(struct tty_struct *tty) | |
543 | { | |
544 | struct slcan *sl; | |
545 | int err; | |
546 | ||
547 | if (!capable(CAP_NET_ADMIN)) | |
548 | return -EPERM; | |
549 | ||
550 | if (tty->ops->write == NULL) | |
551 | return -EOPNOTSUPP; | |
552 | ||
553 | /* RTnetlink lock is misused here to serialize concurrent | |
554 | opens of slcan channels. There are better ways, but it is | |
555 | the simplest one. | |
556 | */ | |
557 | rtnl_lock(); | |
558 | ||
559 | /* Collect hanged up channels. */ | |
560 | slc_sync(); | |
561 | ||
562 | sl = tty->disc_data; | |
563 | ||
564 | err = -EEXIST; | |
565 | /* First make sure we're not already connected. */ | |
566 | if (sl && sl->magic == SLCAN_MAGIC) | |
567 | goto err_exit; | |
568 | ||
569 | /* OK. Find a free SLCAN channel to use. */ | |
570 | err = -ENFILE; | |
571 | sl = slc_alloc(tty_devnum(tty)); | |
572 | if (sl == NULL) | |
573 | goto err_exit; | |
574 | ||
575 | sl->tty = tty; | |
576 | tty->disc_data = sl; | |
a1044e36 OH |
577 | |
578 | if (!test_bit(SLF_INUSE, &sl->flags)) { | |
579 | /* Perform the low-level SLCAN initialization. */ | |
580 | sl->rcount = 0; | |
581 | sl->xleft = 0; | |
582 | ||
583 | set_bit(SLF_INUSE, &sl->flags); | |
584 | ||
585 | err = register_netdevice(sl->dev); | |
586 | if (err) | |
587 | goto err_free_chan; | |
588 | } | |
589 | ||
590 | /* Done. We have linked the TTY line to a channel. */ | |
591 | rtnl_unlock(); | |
592 | tty->receive_room = 65536; /* We don't flow control */ | |
0d4420a9 OH |
593 | |
594 | /* TTY layer expects 0 on success */ | |
595 | return 0; | |
a1044e36 OH |
596 | |
597 | err_free_chan: | |
598 | sl->tty = NULL; | |
599 | tty->disc_data = NULL; | |
600 | clear_bit(SLF_INUSE, &sl->flags); | |
601 | ||
602 | err_exit: | |
603 | rtnl_unlock(); | |
604 | ||
605 | /* Count references from TTY module */ | |
606 | return err; | |
607 | } | |
608 | ||
609 | /* | |
610 | * Close down a SLCAN channel. | |
611 | * This means flushing out any pending queues, and then returning. This | |
612 | * call is serialized against other ldisc functions. | |
613 | * | |
614 | * We also use this method for a hangup event. | |
615 | */ | |
616 | ||
617 | static void slcan_close(struct tty_struct *tty) | |
618 | { | |
619 | struct slcan *sl = (struct slcan *) tty->disc_data; | |
620 | ||
621 | /* First make sure we're connected. */ | |
622 | if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty) | |
623 | return; | |
624 | ||
625 | tty->disc_data = NULL; | |
626 | sl->tty = NULL; | |
a1044e36 OH |
627 | |
628 | /* Flush network side */ | |
629 | unregister_netdev(sl->dev); | |
630 | /* This will complete via sl_free_netdev */ | |
631 | } | |
632 | ||
633 | static int slcan_hangup(struct tty_struct *tty) | |
634 | { | |
635 | slcan_close(tty); | |
636 | return 0; | |
637 | } | |
638 | ||
639 | /* Perform I/O control on an active SLCAN channel. */ | |
640 | static int slcan_ioctl(struct tty_struct *tty, struct file *file, | |
641 | unsigned int cmd, unsigned long arg) | |
642 | { | |
643 | struct slcan *sl = (struct slcan *) tty->disc_data; | |
644 | unsigned int tmp; | |
645 | ||
646 | /* First make sure we're connected. */ | |
647 | if (!sl || sl->magic != SLCAN_MAGIC) | |
648 | return -EINVAL; | |
649 | ||
650 | switch (cmd) { | |
651 | case SIOCGIFNAME: | |
652 | tmp = strlen(sl->dev->name) + 1; | |
653 | if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) | |
654 | return -EFAULT; | |
655 | return 0; | |
656 | ||
657 | case SIOCSIFHWADDR: | |
658 | return -EINVAL; | |
659 | ||
660 | default: | |
661 | return tty_mode_ioctl(tty, file, cmd, arg); | |
662 | } | |
663 | } | |
664 | ||
665 | static struct tty_ldisc_ops slc_ldisc = { | |
666 | .owner = THIS_MODULE, | |
667 | .magic = TTY_LDISC_MAGIC, | |
668 | .name = "slcan", | |
669 | .open = slcan_open, | |
670 | .close = slcan_close, | |
671 | .hangup = slcan_hangup, | |
672 | .ioctl = slcan_ioctl, | |
673 | .receive_buf = slcan_receive_buf, | |
674 | .write_wakeup = slcan_write_wakeup, | |
675 | }; | |
676 | ||
677 | static int __init slcan_init(void) | |
678 | { | |
679 | int status; | |
680 | ||
681 | if (maxdev < 4) | |
682 | maxdev = 4; /* Sanity */ | |
683 | ||
684 | printk(banner); | |
685 | printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev); | |
686 | ||
687 | slcan_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL); | |
e404decb | 688 | if (!slcan_devs) |
a1044e36 | 689 | return -ENOMEM; |
a1044e36 OH |
690 | |
691 | /* Fill in our line protocol discipline, and register it */ | |
692 | status = tty_register_ldisc(N_SLCAN, &slc_ldisc); | |
693 | if (status) { | |
694 | printk(KERN_ERR "slcan: can't register line discipline\n"); | |
695 | kfree(slcan_devs); | |
696 | } | |
697 | return status; | |
698 | } | |
699 | ||
700 | static void __exit slcan_exit(void) | |
701 | { | |
702 | int i; | |
703 | struct net_device *dev; | |
704 | struct slcan *sl; | |
705 | unsigned long timeout = jiffies + HZ; | |
706 | int busy = 0; | |
707 | ||
708 | if (slcan_devs == NULL) | |
709 | return; | |
710 | ||
711 | /* First of all: check for active disciplines and hangup them. | |
712 | */ | |
713 | do { | |
714 | if (busy) | |
715 | msleep_interruptible(100); | |
716 | ||
717 | busy = 0; | |
718 | for (i = 0; i < maxdev; i++) { | |
719 | dev = slcan_devs[i]; | |
720 | if (!dev) | |
721 | continue; | |
722 | sl = netdev_priv(dev); | |
723 | spin_lock_bh(&sl->lock); | |
724 | if (sl->tty) { | |
725 | busy++; | |
726 | tty_hangup(sl->tty); | |
727 | } | |
728 | spin_unlock_bh(&sl->lock); | |
729 | } | |
730 | } while (busy && time_before(jiffies, timeout)); | |
731 | ||
732 | /* FIXME: hangup is async so we should wait when doing this second | |
733 | phase */ | |
734 | ||
735 | for (i = 0; i < maxdev; i++) { | |
736 | dev = slcan_devs[i]; | |
737 | if (!dev) | |
738 | continue; | |
739 | slcan_devs[i] = NULL; | |
740 | ||
741 | sl = netdev_priv(dev); | |
742 | if (sl->tty) { | |
743 | printk(KERN_ERR "%s: tty discipline still running\n", | |
744 | dev->name); | |
745 | /* Intentionally leak the control block. */ | |
746 | dev->destructor = NULL; | |
747 | } | |
748 | ||
749 | unregister_netdev(dev); | |
750 | } | |
751 | ||
752 | kfree(slcan_devs); | |
753 | slcan_devs = NULL; | |
754 | ||
755 | i = tty_unregister_ldisc(N_SLCAN); | |
756 | if (i) | |
757 | printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i); | |
758 | } | |
759 | ||
760 | module_init(slcan_init); | |
761 | module_exit(slcan_exit); |