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Linux 2.6.20.7
[linux/fpc-iii.git] / drivers / net / hamradio / mkiss.c
blobd08fbc3966481fd40c6d790efbf6b455abc2e56a
1 /*
2 * This program is free software; you can distribute it and/or modify it
3 * under the terms of the GNU General Public License (Version 2) as
4 * published by the Free Software Foundation.
5 *
6 * This program is distributed in the hope it will be useful, but WITHOUT
7 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
8 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
9 * for more details.
10 *
11 * You should have received a copy of the GNU General Public License along
12 * with this program; if not, write to the Free Software Foundation, Inc.,
13 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
14 *
15 * Copyright (C) Hans Alblas PE1AYX <hans@esrac.ele.tue.nl>
16 * Copyright (C) 2004, 05 Ralf Baechle DL5RB <ralf@linux-mips.org>
17 * Copyright (C) 2004, 05 Thomas Osterried DL9SAU <thomas@x-berg.in-berlin.de>
18 */
19 #include <linux/module.h>
20 #include <asm/system.h>
21 #include <linux/bitops.h>
22 #include <asm/uaccess.h>
23 #include <linux/crc16.h>
24 #include <linux/string.h>
25 #include <linux/mm.h>
26 #include <linux/interrupt.h>
27 #include <linux/in.h>
28 #include <linux/inet.h>
29 #include <linux/tty.h>
30 #include <linux/errno.h>
31 #include <linux/netdevice.h>
32 #include <linux/major.h>
33 #include <linux/init.h>
34 #include <linux/rtnetlink.h>
35 #include <linux/etherdevice.h>
36 #include <linux/skbuff.h>
37 #include <linux/if_arp.h>
38 #include <linux/jiffies.h>
39
40 #include <net/ax25.h>
41
42 #define AX_MTU 236
43
44 /* SLIP/KISS protocol characters. */
45 #define END 0300 /* indicates end of frame */
46 #define ESC 0333 /* indicates byte stuffing */
47 #define ESC_END 0334 /* ESC ESC_END means END 'data' */
48 #define ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */
49
50 struct mkiss {
51 struct tty_struct *tty; /* ptr to TTY structure */
52 struct net_device *dev; /* easy for intr handling */
53
54 /* These are pointers to the malloc()ed frame buffers. */
55 spinlock_t buflock;/* lock for rbuf and xbuf */
56 unsigned char *rbuff; /* receiver buffer */
57 int rcount; /* received chars counter */
58 unsigned char *xbuff; /* transmitter buffer */
59 unsigned char *xhead; /* pointer to next byte to XMIT */
60 int xleft; /* bytes left in XMIT queue */
61
62 struct net_device_stats stats;
63
64 /* Detailed SLIP statistics. */
65 int mtu; /* Our mtu (to spot changes!) */
66 int buffsize; /* Max buffers sizes */
67
68 unsigned long flags; /* Flag values/ mode etc */
69 /* long req'd: used by set_bit --RR */
70 #define AXF_INUSE 0 /* Channel in use */
71 #define AXF_ESCAPE 1 /* ESC received */
72 #define AXF_ERROR 2 /* Parity, etc. error */
73 #define AXF_KEEPTEST 3 /* Keepalive test flag */
74 #define AXF_OUTWAIT 4 /* is outpacket was flag */
75
76 int mode;
77 int crcmode; /* MW: for FlexNet, SMACK etc. */
78 int crcauto; /* CRC auto mode */
79
80 #define CRC_MODE_NONE 0
81 #define CRC_MODE_FLEX 1
82 #define CRC_MODE_SMACK 2
83 #define CRC_MODE_FLEX_TEST 3
84 #define CRC_MODE_SMACK_TEST 4
85
86 atomic_t refcnt;
87 struct semaphore dead_sem;
88 };
89
90 /*---------------------------------------------------------------------------*/
91
92 static const unsigned short crc_flex_table[] = {
93 0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38,
94 0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770,
95 0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9,
96 0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1,
97 0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a,
98 0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672,
99 0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb,
100 0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3,
101 0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c,
102 0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574,
103 0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd,
104 0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5,
105 0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e,
106 0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476,
107 0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf,
108 0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7,
109 0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30,
110 0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378,
111 0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1,
112 0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9,
113 0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32,
114 0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a,
115 0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3,
116 0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb,
117 0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34,
118 0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c,
119 0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5,
120 0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd,
121 0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36,
122 0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e,
123 0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7,
124 0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff
125 };
126
127 static unsigned short calc_crc_flex(unsigned char *cp, int size)
128 {
129 unsigned short crc = 0xffff;
130
131 while (size--)
132 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
133
134 return crc;
135 }
136
137 static int check_crc_flex(unsigned char *cp, int size)
138 {
139 unsigned short crc = 0xffff;
140
141 if (size < 3)
142 return -1;
143
144 while (size--)
145 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
146
147 if ((crc & 0xffff) != 0x7070)
148 return -1;
149
150 return 0;
151 }
152
153 static int check_crc_16(unsigned char *cp, int size)
154 {
155 unsigned short crc = 0x0000;
156
157 if (size < 3)
158 return -1;
159
160 crc = crc16(0, cp, size);
161
162 if (crc != 0x0000)
163 return -1;
164
165 return 0;
166 }
167
168 /*
169 * Standard encapsulation
170 */
171
172 static int kiss_esc(unsigned char *s, unsigned char *d, int len)
173 {
174 unsigned char *ptr = d;
175 unsigned char c;
176
177 /*
178 * Send an initial END character to flush out any data that may have
179 * accumulated in the receiver due to line noise.
180 */
181
182 *ptr++ = END;
183
184 while (len-- > 0) {
185 switch (c = *s++) {
186 case END:
187 *ptr++ = ESC;
188 *ptr++ = ESC_END;
189 break;
190 case ESC:
191 *ptr++ = ESC;
192 *ptr++ = ESC_ESC;
193 break;
194 default:
195 *ptr++ = c;
196 break;
197 }
198 }
199
200 *ptr++ = END;
201
202 return ptr - d;
203 }
204
205 /*
206 * MW:
207 * OK its ugly, but tell me a better solution without copying the
208 * packet to a temporary buffer :-)
209 */
210 static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc,
211 int len)
212 {
213 unsigned char *ptr = d;
214 unsigned char c=0;
215
216 *ptr++ = END;
217 while (len > 0) {
218 if (len > 2)
219 c = *s++;
220 else if (len > 1)
221 c = crc >> 8;
222 else if (len > 0)
223 c = crc & 0xff;
224
225 len--;
226
227 switch (c) {
228 case END:
229 *ptr++ = ESC;
230 *ptr++ = ESC_END;
231 break;
232 case ESC:
233 *ptr++ = ESC;
234 *ptr++ = ESC_ESC;
235 break;
236 default:
237 *ptr++ = c;
238 break;
239 }
240 }
241 *ptr++ = END;
242
243 return ptr - d;
244 }
245
246 /* Send one completely decapsulated AX.25 packet to the AX.25 layer. */
247 static void ax_bump(struct mkiss *ax)
248 {
249 struct sk_buff *skb;
250 int count;
251
252 spin_lock_bh(&ax->buflock);
253 if (ax->rbuff[0] > 0x0f) {
254 if (ax->rbuff[0] & 0x80) {
255 if (check_crc_16(ax->rbuff, ax->rcount) < 0) {
256 ax->stats.rx_errors++;
257 spin_unlock_bh(&ax->buflock);
258
259 return;
260 }
261 if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) {
262 printk(KERN_INFO
263 "mkiss: %s: Switchting to crc-smack\n",
264 ax->dev->name);
265 ax->crcmode = CRC_MODE_SMACK;
266 }
267 ax->rcount -= 2;
268 *ax->rbuff &= ~0x80;
269 } else if (ax->rbuff[0] & 0x20) {
270 if (check_crc_flex(ax->rbuff, ax->rcount) < 0) {
271 ax->stats.rx_errors++;
272 spin_unlock_bh(&ax->buflock);
273 return;
274 }
275 if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) {
276 printk(KERN_INFO
277 "mkiss: %s: Switchting to crc-flexnet\n",
278 ax->dev->name);
279 ax->crcmode = CRC_MODE_FLEX;
280 }
281 ax->rcount -= 2;
282
283 /*
284 * dl9sau bugfix: the trailling two bytes flexnet crc
285 * will not be passed to the kernel. thus we have to
286 * correct the kissparm signature, because it indicates
287 * a crc but there's none
288 */
289 *ax->rbuff &= ~0x20;
290 }
291 }
292 spin_unlock_bh(&ax->buflock);
293
294 count = ax->rcount;
295
296 if ((skb = dev_alloc_skb(count)) == NULL) {
297 printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n",
298 ax->dev->name);
299 ax->stats.rx_dropped++;
300 return;
301 }
302
303 spin_lock_bh(&ax->buflock);
304 memcpy(skb_put(skb,count), ax->rbuff, count);
305 spin_unlock_bh(&ax->buflock);
306 skb->protocol = ax25_type_trans(skb, ax->dev);
307 netif_rx(skb);
308 ax->dev->last_rx = jiffies;
309 ax->stats.rx_packets++;
310 ax->stats.rx_bytes += count;
311 }
312
313 static void kiss_unesc(struct mkiss *ax, unsigned char s)
314 {
315 switch (s) {
316 case END:
317 /* drop keeptest bit = VSV */
318 if (test_bit(AXF_KEEPTEST, &ax->flags))
319 clear_bit(AXF_KEEPTEST, &ax->flags);
320
321 if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2))
322 ax_bump(ax);
323
324 clear_bit(AXF_ESCAPE, &ax->flags);
325 ax->rcount = 0;
326 return;
327
328 case ESC:
329 set_bit(AXF_ESCAPE, &ax->flags);
330 return;
331 case ESC_ESC:
332 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
333 s = ESC;
334 break;
335 case ESC_END:
336 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
337 s = END;
338 break;
339 }
340
341 spin_lock_bh(&ax->buflock);
342 if (!test_bit(AXF_ERROR, &ax->flags)) {
343 if (ax->rcount < ax->buffsize) {
344 ax->rbuff[ax->rcount++] = s;
345 spin_unlock_bh(&ax->buflock);
346 return;
347 }
348
349 ax->stats.rx_over_errors++;
350 set_bit(AXF_ERROR, &ax->flags);
351 }
352 spin_unlock_bh(&ax->buflock);
353 }
354
355 static int ax_set_mac_address(struct net_device *dev, void *addr)
356 {
357 struct sockaddr_ax25 *sa = addr;
358
359 netif_tx_lock_bh(dev);
360 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
361 netif_tx_unlock_bh(dev);
362
363 return 0;
364 }
365
366 /*---------------------------------------------------------------------------*/
367
368 static void ax_changedmtu(struct mkiss *ax)
369 {
370 struct net_device *dev = ax->dev;
371 unsigned char *xbuff, *rbuff, *oxbuff, *orbuff;
372 int len;
373
374 len = dev->mtu * 2;
375
376 /*
377 * allow for arrival of larger UDP packets, even if we say not to
378 * also fixes a bug in which SunOS sends 512-byte packets even with
379 * an MSS of 128
380 */
381 if (len < 576 * 2)
382 len = 576 * 2;
383
384 xbuff = kmalloc(len + 4, GFP_ATOMIC);
385 rbuff = kmalloc(len + 4, GFP_ATOMIC);
386
387 if (xbuff == NULL || rbuff == NULL) {
388 printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, "
389 "MTU change cancelled.\n",
390 ax->dev->name);
391 dev->mtu = ax->mtu;
392 kfree(xbuff);
393 kfree(rbuff);
394 return;
395 }
396
397 spin_lock_bh(&ax->buflock);
398
399 oxbuff = ax->xbuff;
400 ax->xbuff = xbuff;
401 orbuff = ax->rbuff;
402 ax->rbuff = rbuff;
403
404 if (ax->xleft) {
405 if (ax->xleft <= len) {
406 memcpy(ax->xbuff, ax->xhead, ax->xleft);
407 } else {
408 ax->xleft = 0;
409 ax->stats.tx_dropped++;
410 }
411 }
412
413 ax->xhead = ax->xbuff;
414
415 if (ax->rcount) {
416 if (ax->rcount <= len) {
417 memcpy(ax->rbuff, orbuff, ax->rcount);
418 } else {
419 ax->rcount = 0;
420 ax->stats.rx_over_errors++;
421 set_bit(AXF_ERROR, &ax->flags);
422 }
423 }
424
425 ax->mtu = dev->mtu + 73;
426 ax->buffsize = len;
427
428 spin_unlock_bh(&ax->buflock);
429
430 kfree(oxbuff);
431 kfree(orbuff);
432 }
433
434 /* Encapsulate one AX.25 packet and stuff into a TTY queue. */
435 static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
436 {
437 struct mkiss *ax = netdev_priv(dev);
438 unsigned char *p;
439 int actual, count;
440
441 if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */
442 ax_changedmtu(ax);
443
444 if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */
445 len = ax->mtu;
446 printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name);
447 ax->stats.tx_dropped++;
448 netif_start_queue(dev);
449 return;
450 }
451
452 p = icp;
453
454 spin_lock_bh(&ax->buflock);
455 if ((*p & 0x0f) != 0) {
456 /* Configuration Command (kissparms(1).
457 * Protocol spec says: never append CRC.
458 * This fixes a very old bug in the linux
459 * kiss driver. -- dl9sau */
460 switch (*p & 0xff) {
461 case 0x85:
462 /* command from userspace especially for us,
463 * not for delivery to the tnc */
464 if (len > 1) {
465 int cmd = (p[1] & 0xff);
466 switch(cmd) {
467 case 3:
468 ax->crcmode = CRC_MODE_SMACK;
469 break;
470 case 2:
471 ax->crcmode = CRC_MODE_FLEX;
472 break;
473 case 1:
474 ax->crcmode = CRC_MODE_NONE;
475 break;
476 case 0:
477 default:
478 ax->crcmode = CRC_MODE_SMACK_TEST;
479 cmd = 0;
480 }
481 ax->crcauto = (cmd ? 0 : 1);
482 printk(KERN_INFO "mkiss: %s: crc mode %s %d\n", ax->dev->name, (len) ? "set to" : "is", cmd);
483 }
484 spin_unlock_bh(&ax->buflock);
485 netif_start_queue(dev);
486
487 return;
488 default:
489 count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
490 }
491 } else {
492 unsigned short crc;
493 switch (ax->crcmode) {
494 case CRC_MODE_SMACK_TEST:
495 ax->crcmode = CRC_MODE_FLEX_TEST;
496 printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name);
497 // fall through
498 case CRC_MODE_SMACK:
499 *p |= 0x80;
500 crc = swab16(crc16(0, p, len));
501 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2);
502 break;
503 case CRC_MODE_FLEX_TEST:
504 ax->crcmode = CRC_MODE_NONE;
505 printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name);
506 // fall through
507 case CRC_MODE_FLEX:
508 *p |= 0x20;
509 crc = calc_crc_flex(p, len);
510 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2);
511 break;
512
513 default:
514 count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
515 }
516 }
517 spin_unlock_bh(&ax->buflock);
518
519 set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
520 actual = ax->tty->driver->write(ax->tty, ax->xbuff, count);
521 ax->stats.tx_packets++;
522 ax->stats.tx_bytes += actual;
523
524 ax->dev->trans_start = jiffies;
525 ax->xleft = count - actual;
526 ax->xhead = ax->xbuff + actual;
527 }
528
529 /* Encapsulate an AX.25 packet and kick it into a TTY queue. */
530 static int ax_xmit(struct sk_buff *skb, struct net_device *dev)
531 {
532 struct mkiss *ax = netdev_priv(dev);
533
534 if (!netif_running(dev)) {
535 printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name);
536 return 1;
537 }
538
539 if (netif_queue_stopped(dev)) {
540 /*
541 * May be we must check transmitter timeout here ?
542 * 14 Oct 1994 Dmitry Gorodchanin.
543 */
544 if (time_before(jiffies, dev->trans_start + 20 * HZ)) {
545 /* 20 sec timeout not reached */
546 return 1;
547 }
548
549 printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name,
550 (ax->tty->driver->chars_in_buffer(ax->tty) || ax->xleft) ?
551 "bad line quality" : "driver error");
552
553 ax->xleft = 0;
554 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
555 netif_start_queue(dev);
556 }
557
558 /* We were not busy, so we are now... :-) */
559 if (skb != NULL) {
560 netif_stop_queue(dev);
561 ax_encaps(dev, skb->data, skb->len);
562 kfree_skb(skb);
563 }
564
565 return 0;
566 }
567
568 static int ax_open_dev(struct net_device *dev)
569 {
570 struct mkiss *ax = netdev_priv(dev);
571
572 if (ax->tty == NULL)
573 return -ENODEV;
574
575 return 0;
576 }
577
578 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
579
580 /* Return the frame type ID */
581 static int ax_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
582 void *daddr, void *saddr, unsigned len)
583 {
584 #ifdef CONFIG_INET
585 if (type != htons(ETH_P_AX25))
586 return ax25_hard_header(skb, dev, type, daddr, saddr, len);
587 #endif
588 return 0;
589 }
590
591
592 static int ax_rebuild_header(struct sk_buff *skb)
593 {
594 #ifdef CONFIG_INET
595 return ax25_rebuild_header(skb);
596 #else
597 return 0;
598 #endif
599 }
600
601 #endif /* CONFIG_{AX25,AX25_MODULE} */
602
603 /* Open the low-level part of the AX25 channel. Easy! */
604 static int ax_open(struct net_device *dev)
605 {
606 struct mkiss *ax = netdev_priv(dev);
607 unsigned long len;
608
609 if (ax->tty == NULL)
610 return -ENODEV;
611
612 /*
613 * Allocate the frame buffers:
614 *
615 * rbuff Receive buffer.
616 * xbuff Transmit buffer.
617 */
618 len = dev->mtu * 2;
619
620 /*
621 * allow for arrival of larger UDP packets, even if we say not to
622 * also fixes a bug in which SunOS sends 512-byte packets even with
623 * an MSS of 128
624 */
625 if (len < 576 * 2)
626 len = 576 * 2;
627
628 if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
629 goto norbuff;
630
631 if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
632 goto noxbuff;
633
634 ax->mtu = dev->mtu + 73;
635 ax->buffsize = len;
636 ax->rcount = 0;
637 ax->xleft = 0;
638
639 ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */
640
641 spin_lock_init(&ax->buflock);
642
643 return 0;
644
645 noxbuff:
646 kfree(ax->rbuff);
647
648 norbuff:
649 return -ENOMEM;
650 }
651
652
653 /* Close the low-level part of the AX25 channel. Easy! */
654 static int ax_close(struct net_device *dev)
655 {
656 struct mkiss *ax = netdev_priv(dev);
657
658 if (ax->tty)
659 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
660
661 netif_stop_queue(dev);
662
663 return 0;
664 }
665
666 static struct net_device_stats *ax_get_stats(struct net_device *dev)
667 {
668 struct mkiss *ax = netdev_priv(dev);
669
670 return &ax->stats;
671 }
672
673 static void ax_setup(struct net_device *dev)
674 {
675 /* Finish setting up the DEVICE info. */
676 dev->mtu = AX_MTU;
677 dev->hard_start_xmit = ax_xmit;
678 dev->open = ax_open_dev;
679 dev->stop = ax_close;
680 dev->get_stats = ax_get_stats;
681 dev->set_mac_address = ax_set_mac_address;
682 dev->hard_header_len = 0;
683 dev->addr_len = 0;
684 dev->type = ARPHRD_AX25;
685 dev->tx_queue_len = 10;
686 dev->hard_header = ax_header;
687 dev->rebuild_header = ax_rebuild_header;
688
689 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
690 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
691
692 dev->flags = IFF_BROADCAST | IFF_MULTICAST;
693 }
694
695 /*
696 * We have a potential race on dereferencing tty->disc_data, because the tty
697 * layer provides no locking at all - thus one cpu could be running
698 * sixpack_receive_buf while another calls sixpack_close, which zeroes
699 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
700 * best way to fix this is to use a rwlock in the tty struct, but for now we
701 * use a single global rwlock for all ttys in ppp line discipline.
702 */
703 static DEFINE_RWLOCK(disc_data_lock);
704
705 static struct mkiss *mkiss_get(struct tty_struct *tty)
706 {
707 struct mkiss *ax;
708
709 read_lock(&disc_data_lock);
710 ax = tty->disc_data;
711 if (ax)
712 atomic_inc(&ax->refcnt);
713 read_unlock(&disc_data_lock);
714
715 return ax;
716 }
717
718 static void mkiss_put(struct mkiss *ax)
719 {
720 if (atomic_dec_and_test(&ax->refcnt))
721 up(&ax->dead_sem);
722 }
723
724 static int crc_force = 0; /* Can be overridden with insmod */
725
726 static int mkiss_open(struct tty_struct *tty)
727 {
728 struct net_device *dev;
729 struct mkiss *ax;
730 int err;
731
732 if (!capable(CAP_NET_ADMIN))
733 return -EPERM;
734
735 dev = alloc_netdev(sizeof(struct mkiss), "ax%d", ax_setup);
736 if (!dev) {
737 err = -ENOMEM;
738 goto out;
739 }
740
741 ax = netdev_priv(dev);
742 ax->dev = dev;
743
744 spin_lock_init(&ax->buflock);
745 atomic_set(&ax->refcnt, 1);
746 init_MUTEX_LOCKED(&ax->dead_sem);
747
748 ax->tty = tty;
749 tty->disc_data = ax;
750 tty->receive_room = 65535;
751
752 if (tty->driver->flush_buffer)
753 tty->driver->flush_buffer(tty);
754
755 /* Restore default settings */
756 dev->type = ARPHRD_AX25;
757
758 /* Perform the low-level AX25 initialization. */
759 if ((err = ax_open(ax->dev))) {
760 goto out_free_netdev;
761 }
762
763 if (register_netdev(dev))
764 goto out_free_buffers;
765
766 /* after register_netdev() - because else printk smashes the kernel */
767 switch (crc_force) {
768 case 3:
769 ax->crcmode = CRC_MODE_SMACK;
770 printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n",
771 ax->dev->name);
772 break;
773 case 2:
774 ax->crcmode = CRC_MODE_FLEX;
775 printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n",
776 ax->dev->name);
777 break;
778 case 1:
779 ax->crcmode = CRC_MODE_NONE;
780 printk(KERN_INFO "mkiss: %s: crc mode disabled.\n",
781 ax->dev->name);
782 break;
783 case 0:
784 /* fall through */
785 default:
786 crc_force = 0;
787 printk(KERN_INFO "mkiss: %s: crc mode is auto.\n",
788 ax->dev->name);
789 ax->crcmode = CRC_MODE_SMACK_TEST;
790 }
791 ax->crcauto = (crc_force ? 0 : 1);
792
793 netif_start_queue(dev);
794
795 /* Done. We have linked the TTY line to a channel. */
796 return 0;
797
798 out_free_buffers:
799 kfree(ax->rbuff);
800 kfree(ax->xbuff);
801
802 out_free_netdev:
803 free_netdev(dev);
804
805 out:
806 return err;
807 }
808
809 static void mkiss_close(struct tty_struct *tty)
810 {
811 struct mkiss *ax;
812
813 write_lock(&disc_data_lock);
814 ax = tty->disc_data;
815 tty->disc_data = NULL;
816 write_unlock(&disc_data_lock);
817
818 if (ax == 0)
819 return;
820
821 /*
822 * We have now ensured that nobody can start using ap from now on, but
823 * we have to wait for all existing users to finish.
824 */
825 if (!atomic_dec_and_test(&ax->refcnt))
826 down(&ax->dead_sem);
827
828 unregister_netdev(ax->dev);
829
830 /* Free all AX25 frame buffers. */
831 kfree(ax->rbuff);
832 kfree(ax->xbuff);
833
834 ax->tty = NULL;
835 }
836
837 /* Perform I/O control on an active ax25 channel. */
838 static int mkiss_ioctl(struct tty_struct *tty, struct file *file,
839 unsigned int cmd, unsigned long arg)
840 {
841 struct mkiss *ax = mkiss_get(tty);
842 struct net_device *dev = ax->dev;
843 unsigned int tmp, err;
844
845 /* First make sure we're connected. */
846 if (ax == NULL)
847 return -ENXIO;
848
849 switch (cmd) {
850 case SIOCGIFNAME:
851 err = copy_to_user((void __user *) arg, ax->dev->name,
852 strlen(ax->dev->name) + 1) ? -EFAULT : 0;
853 break;
854
855 case SIOCGIFENCAP:
856 err = put_user(4, (int __user *) arg);
857 break;
858
859 case SIOCSIFENCAP:
860 if (get_user(tmp, (int __user *) arg)) {
861 err = -EFAULT;
862 break;
863 }
864
865 ax->mode = tmp;
866 dev->addr_len = AX25_ADDR_LEN;
867 dev->hard_header_len = AX25_KISS_HEADER_LEN +
868 AX25_MAX_HEADER_LEN + 3;
869 dev->type = ARPHRD_AX25;
870
871 err = 0;
872 break;
873
874 case SIOCSIFHWADDR: {
875 char addr[AX25_ADDR_LEN];
876
877 if (copy_from_user(&addr,
878 (void __user *) arg, AX25_ADDR_LEN)) {
879 err = -EFAULT;
880 break;
881 }
882
883 netif_tx_lock_bh(dev);
884 memcpy(dev->dev_addr, addr, AX25_ADDR_LEN);
885 netif_tx_unlock_bh(dev);
886
887 err = 0;
888 break;
889 }
890 default:
891 err = -ENOIOCTLCMD;
892 }
893
894 mkiss_put(ax);
895
896 return err;
897 }
898
899 /*
900 * Handle the 'receiver data ready' interrupt.
901 * This function is called by the 'tty_io' module in the kernel when
902 * a block of data has been received, which can now be decapsulated
903 * and sent on to the AX.25 layer for further processing.
904 */
905 static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,
906 char *fp, int count)
907 {
908 struct mkiss *ax = mkiss_get(tty);
909
910 if (!ax)
911 return;
912
913 /*
914 * Argh! mtu change time! - costs us the packet part received
915 * at the change
916 */
917 if (ax->mtu != ax->dev->mtu + 73)
918 ax_changedmtu(ax);
919
920 /* Read the characters out of the buffer */
921 while (count--) {
922 if (fp != NULL && *fp++) {
923 if (!test_and_set_bit(AXF_ERROR, &ax->flags))
924 ax->stats.rx_errors++;
925 cp++;
926 continue;
927 }
928
929 kiss_unesc(ax, *cp++);
930 }
931
932 mkiss_put(ax);
933 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags)
934 && tty->driver->unthrottle)
935 tty->driver->unthrottle(tty);
936 }
937
938 /*
939 * Called by the driver when there's room for more data. If we have
940 * more packets to send, we send them here.
941 */
942 static void mkiss_write_wakeup(struct tty_struct *tty)
943 {
944 struct mkiss *ax = mkiss_get(tty);
945 int actual;
946
947 if (!ax)
948 return;
949
950 if (ax->xleft <= 0) {
951 /* Now serial buffer is almost free & we can start
952 * transmission of another packet
953 */
954 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
955
956 netif_wake_queue(ax->dev);
957 goto out;
958 }
959
960 actual = tty->driver->write(tty, ax->xhead, ax->xleft);
961 ax->xleft -= actual;
962 ax->xhead += actual;
963
964 out:
965 mkiss_put(ax);
966 }
967
968 static struct tty_ldisc ax_ldisc = {
969 .owner = THIS_MODULE,
970 .magic = TTY_LDISC_MAGIC,
971 .name = "mkiss",
972 .open = mkiss_open,
973 .close = mkiss_close,
974 .ioctl = mkiss_ioctl,
975 .receive_buf = mkiss_receive_buf,
976 .write_wakeup = mkiss_write_wakeup
977 };
978
979 static char banner[] __initdata = KERN_INFO \
980 "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n";
981 static char msg_regfail[] __initdata = KERN_ERR \
982 "mkiss: can't register line discipline (err = %d)\n";
983
984 static int __init mkiss_init_driver(void)
985 {
986 int status;
987
988 printk(banner);
989
990 if ((status = tty_register_ldisc(N_AX25, &ax_ldisc)) != 0)
991 printk(msg_regfail);
992
993 return status;
994 }
995
996 static const char msg_unregfail[] __exitdata = KERN_ERR \
997 "mkiss: can't unregister line discipline (err = %d)\n";
998
999 static void __exit mkiss_exit_driver(void)
1000 {
1001 int ret;
1002
1003 if ((ret = tty_unregister_ldisc(N_AX25)))
1004 printk(msg_unregfail, ret);
1005 }
1006
1007 MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>");
1008 MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs");
1009 module_param(crc_force, int, 0);
1010 MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]");
1011 MODULE_LICENSE("GPL");
1012 MODULE_ALIAS_LDISC(N_AX25);
1013
1014 module_init(mkiss_init_driver);
1015 module_exit(mkiss_exit_driver);
Linux with added FPC-III support