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Commit | Line | Data |
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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 | |
05780d98 | 21 | * with this program; if not, see http://www.gnu.org/licenses/gpl.html |
a1044e36 OH |
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 | * | |
a1044e36 OH |
36 | */ |
37 | ||
38 | #include <linux/module.h> | |
39 | #include <linux/moduleparam.h> | |
40 | ||
a1044e36 OH |
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> | |
84b3cdc3 | 51 | #include <linux/sched.h> |
a1044e36 OH |
52 | #include <linux/delay.h> |
53 | #include <linux/init.h> | |
81fc70d8 | 54 | #include <linux/kernel.h> |
a1044e36 | 55 | #include <linux/can.h> |
156c2bb9 | 56 | #include <linux/can/skb.h> |
a1044e36 | 57 | |
c477ebd8 | 58 | static __initconst const char banner[] = |
a1044e36 OH |
59 | KERN_INFO "slcan: serial line CAN interface driver\n"; |
60 | ||
61 | MODULE_ALIAS_LDISC(N_SLCAN); | |
62 | MODULE_DESCRIPTION("serial line CAN interface"); | |
63 | MODULE_LICENSE("GPL"); | |
64 | MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>"); | |
65 | ||
66 | #define SLCAN_MAGIC 0x53CA | |
67 | ||
68 | static int maxdev = 10; /* MAX number of SLCAN channels; | |
69 | This can be overridden with | |
70 | insmod slcan.ko maxdev=nnn */ | |
71 | module_param(maxdev, int, 0); | |
72 | MODULE_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 | ||
87397fe1 AN |
77 | #define SLC_CMD_LEN 1 |
78 | #define SLC_SFF_ID_LEN 3 | |
79 | #define SLC_EFF_ID_LEN 8 | |
80 | ||
a1044e36 OH |
81 | struct 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 */ | |
a1044e36 OH |
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 | ||
a1044e36 OH |
142 | /* Send one completely decapsulated can_frame to the network layer */ |
143 | static void slc_bump(struct slcan *sl) | |
144 | { | |
145 | struct sk_buff *skb; | |
146 | struct can_frame cf; | |
87397fe1 AN |
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: | |
a1044e36 | 176 | return; |
87397fe1 | 177 | } |
a1044e36 | 178 | |
87397fe1 | 179 | if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid)) |
a1044e36 OH |
180 | return; |
181 | ||
87397fe1 | 182 | cf.can_id |= tmpid; |
a1044e36 | 183 | |
87397fe1 AN |
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 | |
a1044e36 OH |
188 | return; |
189 | ||
a1044e36 OH |
190 | *(u64 *) (&cf.data) = 0; /* clear payload */ |
191 | ||
87397fe1 AN |
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 | } | |
a1044e36 OH |
204 | } |
205 | ||
156c2bb9 OH |
206 | skb = dev_alloc_skb(sizeof(struct can_frame) + |
207 | sizeof(struct can_skb_priv)); | |
a1044e36 OH |
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; | |
156c2bb9 | 215 | |
2bf3440d OH |
216 | can_skb_reserve(skb); |
217 | can_skb_prv(skb)->ifindex = sl->dev->ifindex; | |
156c2bb9 | 218 | |
a1044e36 OH |
219 | memcpy(skb_put(skb, sizeof(struct can_frame)), |
220 | &cf, sizeof(struct can_frame)); | |
174c95d2 | 221 | netif_rx_ni(skb); |
a1044e36 OH |
222 | |
223 | sl->dev->stats.rx_packets++; | |
224 | sl->dev->stats.rx_bytes += cf.can_dlc; | |
225 | } | |
226 | ||
227 | /* parse tty input stream */ | |
228 | static void slcan_unesc(struct slcan *sl, unsigned char s) | |
229 | { | |
a1044e36 OH |
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. */ | |
254 | static void slc_encaps(struct slcan *sl, struct can_frame *cf) | |
255 | { | |
87397fe1 AN |
256 | int actual, i; |
257 | unsigned char *pos; | |
258 | unsigned char *endpos; | |
259 | canid_t id = cf->can_id; | |
260 | ||
261 | pos = sl->xbuff; | |
a1044e36 OH |
262 | |
263 | if (cf->can_id & CAN_RTR_FLAG) | |
87397fe1 | 264 | *pos = 'R'; /* becomes 'r' in standard frame format (SFF) */ |
a1044e36 | 265 | else |
87397fe1 | 266 | *pos = 'T'; /* becomes 't' in standard frame format (SSF) */ |
a1044e36 | 267 | |
87397fe1 AN |
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; | |
a1044e36 | 286 | |
87397fe1 | 287 | *pos++ = cf->can_dlc + '0'; |
a1044e36 | 288 | |
87397fe1 AN |
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 | } | |
a1044e36 | 294 | |
87397fe1 | 295 | *pos++ = '\r'; |
a1044e36 OH |
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); | |
87397fe1 AN |
306 | actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff); |
307 | sl->xleft = (pos - sl->xbuff) - actual; | |
a1044e36 OH |
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 | */ | |
316 | static 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 | ||
367525c8 | 325 | spin_lock_bh(&sl->lock); |
a1044e36 OH |
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); | |
367525c8 | 331 | spin_unlock_bh(&sl->lock); |
a1044e36 OH |
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; | |
367525c8 | 339 | spin_unlock_bh(&sl->lock); |
a1044e36 OH |
340 | } |
341 | ||
342 | /* Send a can_frame to a TTY queue. */ | |
343 | static 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 | ||
365 | out: | |
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 */ | |
376 | static 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 */ | |
394 | static 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 */ | |
407 | static 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 | ||
c971fa2a OH |
414 | static int slcan_change_mtu(struct net_device *dev, int new_mtu) |
415 | { | |
416 | return -EINVAL; | |
417 | } | |
418 | ||
a1044e36 OH |
419 | static const struct net_device_ops slc_netdev_ops = { |
420 | .ndo_open = slc_open, | |
421 | .ndo_stop = slc_close, | |
422 | .ndo_start_xmit = slc_xmit, | |
c971fa2a | 423 | .ndo_change_mtu = slcan_change_mtu, |
a1044e36 OH |
424 | }; |
425 | ||
426 | static 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; | |
34324dc2 | 440 | dev->features = NETIF_F_HW_CSUM; |
a1044e36 OH |
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 | ||
55db4c64 | 456 | static void slcan_receive_buf(struct tty_struct *tty, |
a1044e36 OH |
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)) | |
55db4c64 | 462 | return; |
a1044e36 OH |
463 | |
464 | /* Read the characters out of the buffer */ | |
55db4c64 | 465 | while (count--) { |
a1044e36 OH |
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 */ | |
481 | static 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); | |
7ad711b4 | 493 | if (sl->tty) |
a1044e36 OH |
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. */ | |
501 | static struct slcan *slc_alloc(dev_t line) | |
502 | { | |
503 | int i; | |
2af4ba85 | 504 | char name[IFNAMSIZ]; |
a1044e36 OH |
505 | struct net_device *dev = NULL; |
506 | struct slcan *sl; | |
507 | ||
a1044e36 OH |
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 | ||
2af4ba85 OH |
519 | sprintf(name, "slcan%d", i); |
520 | dev = alloc_netdev(sizeof(*sl), name, slc_setup); | |
521 | if (!dev) | |
522 | return NULL; | |
a1044e36 | 523 | |
2af4ba85 | 524 | dev->base_addr = i; |
a1044e36 OH |
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 | ||
546 | static 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; | |
a1044e36 OH |
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 */ | |
0d4420a9 OH |
597 | |
598 | /* TTY layer expects 0 on success */ | |
599 | return 0; | |
a1044e36 OH |
600 | |
601 | err_free_chan: | |
602 | sl->tty = NULL; | |
603 | tty->disc_data = NULL; | |
604 | clear_bit(SLF_INUSE, &sl->flags); | |
605 | ||
606 | err_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 | ||
621 | static 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; | |
a1044e36 OH |
631 | |
632 | /* Flush network side */ | |
633 | unregister_netdev(sl->dev); | |
634 | /* This will complete via sl_free_netdev */ | |
635 | } | |
636 | ||
637 | static 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. */ | |
644 | static 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 | ||
669 | static 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 | ||
681 | static 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); | |
e404decb | 692 | if (!slcan_devs) |
a1044e36 | 693 | return -ENOMEM; |
a1044e36 OH |
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 | ||
704 | static 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 | ||
764 | module_init(slcan_init); | |
765 | module_exit(slcan_exit); |