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net: use symbolic values for ndo_start_xmit() return codes
[deliverable/linux.git] / drivers / net / hamradio / mkiss.c
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 /* Detailed SLIP statistics. */
63 int mtu; /* Our mtu (to spot changes!) */
64 int buffsize; /* Max buffers sizes */
65
66 unsigned long flags; /* Flag values/ mode etc */
67 /* long req'd: used by set_bit --RR */
68 #define AXF_INUSE 0 /* Channel in use */
69 #define AXF_ESCAPE 1 /* ESC received */
70 #define AXF_ERROR 2 /* Parity, etc. error */
71 #define AXF_KEEPTEST 3 /* Keepalive test flag */
72 #define AXF_OUTWAIT 4 /* is outpacket was flag */
73
74 int mode;
75 int crcmode; /* MW: for FlexNet, SMACK etc. */
76 int crcauto; /* CRC auto mode */
77
78 #define CRC_MODE_NONE 0
79 #define CRC_MODE_FLEX 1
80 #define CRC_MODE_SMACK 2
81 #define CRC_MODE_FLEX_TEST 3
82 #define CRC_MODE_SMACK_TEST 4
83
84 atomic_t refcnt;
85 struct semaphore dead_sem;
86 };
87
88 /*---------------------------------------------------------------------------*/
89
90 static const unsigned short crc_flex_table[] = {
91 0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38,
92 0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770,
93 0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9,
94 0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1,
95 0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a,
96 0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672,
97 0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb,
98 0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3,
99 0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c,
100 0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574,
101 0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd,
102 0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5,
103 0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e,
104 0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476,
105 0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf,
106 0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7,
107 0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30,
108 0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378,
109 0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1,
110 0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9,
111 0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32,
112 0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a,
113 0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3,
114 0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb,
115 0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34,
116 0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c,
117 0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5,
118 0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd,
119 0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36,
120 0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e,
121 0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7,
122 0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff
123 };
124
125 static unsigned short calc_crc_flex(unsigned char *cp, int size)
126 {
127 unsigned short crc = 0xffff;
128
129 while (size--)
130 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
131
132 return crc;
133 }
134
135 static int check_crc_flex(unsigned char *cp, int size)
136 {
137 unsigned short crc = 0xffff;
138
139 if (size < 3)
140 return -1;
141
142 while (size--)
143 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
144
145 if ((crc & 0xffff) != 0x7070)
146 return -1;
147
148 return 0;
149 }
150
151 static int check_crc_16(unsigned char *cp, int size)
152 {
153 unsigned short crc = 0x0000;
154
155 if (size < 3)
156 return -1;
157
158 crc = crc16(0, cp, size);
159
160 if (crc != 0x0000)
161 return -1;
162
163 return 0;
164 }
165
166 /*
167 * Standard encapsulation
168 */
169
170 static int kiss_esc(unsigned char *s, unsigned char *d, int len)
171 {
172 unsigned char *ptr = d;
173 unsigned char c;
174
175 /*
176 * Send an initial END character to flush out any data that may have
177 * accumulated in the receiver due to line noise.
178 */
179
180 *ptr++ = END;
181
182 while (len-- > 0) {
183 switch (c = *s++) {
184 case END:
185 *ptr++ = ESC;
186 *ptr++ = ESC_END;
187 break;
188 case ESC:
189 *ptr++ = ESC;
190 *ptr++ = ESC_ESC;
191 break;
192 default:
193 *ptr++ = c;
194 break;
195 }
196 }
197
198 *ptr++ = END;
199
200 return ptr - d;
201 }
202
203 /*
204 * MW:
205 * OK its ugly, but tell me a better solution without copying the
206 * packet to a temporary buffer :-)
207 */
208 static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc,
209 int len)
210 {
211 unsigned char *ptr = d;
212 unsigned char c=0;
213
214 *ptr++ = END;
215 while (len > 0) {
216 if (len > 2)
217 c = *s++;
218 else if (len > 1)
219 c = crc >> 8;
220 else if (len > 0)
221 c = crc & 0xff;
222
223 len--;
224
225 switch (c) {
226 case END:
227 *ptr++ = ESC;
228 *ptr++ = ESC_END;
229 break;
230 case ESC:
231 *ptr++ = ESC;
232 *ptr++ = ESC_ESC;
233 break;
234 default:
235 *ptr++ = c;
236 break;
237 }
238 }
239 *ptr++ = END;
240
241 return ptr - d;
242 }
243
244 /* Send one completely decapsulated AX.25 packet to the AX.25 layer. */
245 static void ax_bump(struct mkiss *ax)
246 {
247 struct sk_buff *skb;
248 int count;
249
250 spin_lock_bh(&ax->buflock);
251 if (ax->rbuff[0] > 0x0f) {
252 if (ax->rbuff[0] & 0x80) {
253 if (check_crc_16(ax->rbuff, ax->rcount) < 0) {
254 ax->dev->stats.rx_errors++;
255 spin_unlock_bh(&ax->buflock);
256
257 return;
258 }
259 if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) {
260 printk(KERN_INFO
261 "mkiss: %s: Switchting to crc-smack\n",
262 ax->dev->name);
263 ax->crcmode = CRC_MODE_SMACK;
264 }
265 ax->rcount -= 2;
266 *ax->rbuff &= ~0x80;
267 } else if (ax->rbuff[0] & 0x20) {
268 if (check_crc_flex(ax->rbuff, ax->rcount) < 0) {
269 ax->dev->stats.rx_errors++;
270 spin_unlock_bh(&ax->buflock);
271 return;
272 }
273 if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) {
274 printk(KERN_INFO
275 "mkiss: %s: Switchting to crc-flexnet\n",
276 ax->dev->name);
277 ax->crcmode = CRC_MODE_FLEX;
278 }
279 ax->rcount -= 2;
280
281 /*
282 * dl9sau bugfix: the trailling two bytes flexnet crc
283 * will not be passed to the kernel. thus we have to
284 * correct the kissparm signature, because it indicates
285 * a crc but there's none
286 */
287 *ax->rbuff &= ~0x20;
288 }
289 }
290
291 count = ax->rcount;
292
293 if ((skb = dev_alloc_skb(count)) == NULL) {
294 printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n",
295 ax->dev->name);
296 ax->dev->stats.rx_dropped++;
297 spin_unlock_bh(&ax->buflock);
298 return;
299 }
300
301 memcpy(skb_put(skb,count), ax->rbuff, count);
302 skb->protocol = ax25_type_trans(skb, ax->dev);
303 netif_rx(skb);
304 ax->dev->stats.rx_packets++;
305 ax->dev->stats.rx_bytes += count;
306 spin_unlock_bh(&ax->buflock);
307 }
308
309 static void kiss_unesc(struct mkiss *ax, unsigned char s)
310 {
311 switch (s) {
312 case END:
313 /* drop keeptest bit = VSV */
314 if (test_bit(AXF_KEEPTEST, &ax->flags))
315 clear_bit(AXF_KEEPTEST, &ax->flags);
316
317 if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2))
318 ax_bump(ax);
319
320 clear_bit(AXF_ESCAPE, &ax->flags);
321 ax->rcount = 0;
322 return;
323
324 case ESC:
325 set_bit(AXF_ESCAPE, &ax->flags);
326 return;
327 case ESC_ESC:
328 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
329 s = ESC;
330 break;
331 case ESC_END:
332 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
333 s = END;
334 break;
335 }
336
337 spin_lock_bh(&ax->buflock);
338 if (!test_bit(AXF_ERROR, &ax->flags)) {
339 if (ax->rcount < ax->buffsize) {
340 ax->rbuff[ax->rcount++] = s;
341 spin_unlock_bh(&ax->buflock);
342 return;
343 }
344
345 ax->dev->stats.rx_over_errors++;
346 set_bit(AXF_ERROR, &ax->flags);
347 }
348 spin_unlock_bh(&ax->buflock);
349 }
350
351 static int ax_set_mac_address(struct net_device *dev, void *addr)
352 {
353 struct sockaddr_ax25 *sa = addr;
354
355 netif_tx_lock_bh(dev);
356 netif_addr_lock(dev);
357 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
358 netif_addr_unlock(dev);
359 netif_tx_unlock_bh(dev);
360
361 return 0;
362 }
363
364 /*---------------------------------------------------------------------------*/
365
366 static void ax_changedmtu(struct mkiss *ax)
367 {
368 struct net_device *dev = ax->dev;
369 unsigned char *xbuff, *rbuff, *oxbuff, *orbuff;
370 int len;
371
372 len = dev->mtu * 2;
373
374 /*
375 * allow for arrival of larger UDP packets, even if we say not to
376 * also fixes a bug in which SunOS sends 512-byte packets even with
377 * an MSS of 128
378 */
379 if (len < 576 * 2)
380 len = 576 * 2;
381
382 xbuff = kmalloc(len + 4, GFP_ATOMIC);
383 rbuff = kmalloc(len + 4, GFP_ATOMIC);
384
385 if (xbuff == NULL || rbuff == NULL) {
386 printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, "
387 "MTU change cancelled.\n",
388 ax->dev->name);
389 dev->mtu = ax->mtu;
390 kfree(xbuff);
391 kfree(rbuff);
392 return;
393 }
394
395 spin_lock_bh(&ax->buflock);
396
397 oxbuff = ax->xbuff;
398 ax->xbuff = xbuff;
399 orbuff = ax->rbuff;
400 ax->rbuff = rbuff;
401
402 if (ax->xleft) {
403 if (ax->xleft <= len) {
404 memcpy(ax->xbuff, ax->xhead, ax->xleft);
405 } else {
406 ax->xleft = 0;
407 dev->stats.tx_dropped++;
408 }
409 }
410
411 ax->xhead = ax->xbuff;
412
413 if (ax->rcount) {
414 if (ax->rcount <= len) {
415 memcpy(ax->rbuff, orbuff, ax->rcount);
416 } else {
417 ax->rcount = 0;
418 dev->stats.rx_over_errors++;
419 set_bit(AXF_ERROR, &ax->flags);
420 }
421 }
422
423 ax->mtu = dev->mtu + 73;
424 ax->buffsize = len;
425
426 spin_unlock_bh(&ax->buflock);
427
428 kfree(oxbuff);
429 kfree(orbuff);
430 }
431
432 /* Encapsulate one AX.25 packet and stuff into a TTY queue. */
433 static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
434 {
435 struct mkiss *ax = netdev_priv(dev);
436 unsigned char *p;
437 int actual, count;
438
439 if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */
440 ax_changedmtu(ax);
441
442 if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */
443 len = ax->mtu;
444 printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name);
445 dev->stats.tx_dropped++;
446 netif_start_queue(dev);
447 return;
448 }
449
450 p = icp;
451
452 spin_lock_bh(&ax->buflock);
453 if ((*p & 0x0f) != 0) {
454 /* Configuration Command (kissparms(1).
455 * Protocol spec says: never append CRC.
456 * This fixes a very old bug in the linux
457 * kiss driver. -- dl9sau */
458 switch (*p & 0xff) {
459 case 0x85:
460 /* command from userspace especially for us,
461 * not for delivery to the tnc */
462 if (len > 1) {
463 int cmd = (p[1] & 0xff);
464 switch(cmd) {
465 case 3:
466 ax->crcmode = CRC_MODE_SMACK;
467 break;
468 case 2:
469 ax->crcmode = CRC_MODE_FLEX;
470 break;
471 case 1:
472 ax->crcmode = CRC_MODE_NONE;
473 break;
474 case 0:
475 default:
476 ax->crcmode = CRC_MODE_SMACK_TEST;
477 cmd = 0;
478 }
479 ax->crcauto = (cmd ? 0 : 1);
480 printk(KERN_INFO "mkiss: %s: crc mode %s %d\n", ax->dev->name, (len) ? "set to" : "is", cmd);
481 }
482 spin_unlock_bh(&ax->buflock);
483 netif_start_queue(dev);
484
485 return;
486 default:
487 count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
488 }
489 } else {
490 unsigned short crc;
491 switch (ax->crcmode) {
492 case CRC_MODE_SMACK_TEST:
493 ax->crcmode = CRC_MODE_FLEX_TEST;
494 printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name);
495 // fall through
496 case CRC_MODE_SMACK:
497 *p |= 0x80;
498 crc = swab16(crc16(0, p, len));
499 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2);
500 break;
501 case CRC_MODE_FLEX_TEST:
502 ax->crcmode = CRC_MODE_NONE;
503 printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name);
504 // fall through
505 case CRC_MODE_FLEX:
506 *p |= 0x20;
507 crc = calc_crc_flex(p, len);
508 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2);
509 break;
510
511 default:
512 count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
513 }
514 }
515 spin_unlock_bh(&ax->buflock);
516
517 set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
518 actual = ax->tty->ops->write(ax->tty, ax->xbuff, count);
519 dev->stats.tx_packets++;
520 dev->stats.tx_bytes += actual;
521
522 ax->dev->trans_start = jiffies;
523 ax->xleft = count - actual;
524 ax->xhead = ax->xbuff + actual;
525 }
526
527 /* Encapsulate an AX.25 packet and kick it into a TTY queue. */
528 static int ax_xmit(struct sk_buff *skb, struct net_device *dev)
529 {
530 struct mkiss *ax = netdev_priv(dev);
531
532 if (!netif_running(dev)) {
533 printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name);
534 return NETDEV_TX_BUSY;
535 }
536
537 if (netif_queue_stopped(dev)) {
538 /*
539 * May be we must check transmitter timeout here ?
540 * 14 Oct 1994 Dmitry Gorodchanin.
541 */
542 if (time_before(jiffies, dev->trans_start + 20 * HZ)) {
543 /* 20 sec timeout not reached */
544 return NETDEV_TX_BUSY;
545 }
546
547 printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name,
548 (tty_chars_in_buffer(ax->tty) || ax->xleft) ?
549 "bad line quality" : "driver error");
550
551 ax->xleft = 0;
552 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
553 netif_start_queue(dev);
554 }
555
556 /* We were not busy, so we are now... :-) */
557 if (skb != NULL) {
558 netif_stop_queue(dev);
559 ax_encaps(dev, skb->data, skb->len);
560 kfree_skb(skb);
561 }
562
563 return 0;
564 }
565
566 static int ax_open_dev(struct net_device *dev)
567 {
568 struct mkiss *ax = netdev_priv(dev);
569
570 if (ax->tty == NULL)
571 return -ENODEV;
572
573 return 0;
574 }
575
576 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
577
578 /* Return the frame type ID */
579 static int ax_header(struct sk_buff *skb, struct net_device *dev,
580 unsigned short type, const void *daddr,
581 const void *saddr, unsigned len)
582 {
583 #ifdef CONFIG_INET
584 if (type != ETH_P_AX25)
585 return ax25_hard_header(skb, dev, type, daddr, saddr, len);
586 #endif
587 return 0;
588 }
589
590
591 static int ax_rebuild_header(struct sk_buff *skb)
592 {
593 #ifdef CONFIG_INET
594 return ax25_rebuild_header(skb);
595 #else
596 return 0;
597 #endif
598 }
599
600 #endif /* CONFIG_{AX25,AX25_MODULE} */
601
602 /* Open the low-level part of the AX25 channel. Easy! */
603 static int ax_open(struct net_device *dev)
604 {
605 struct mkiss *ax = netdev_priv(dev);
606 unsigned long len;
607
608 if (ax->tty == NULL)
609 return -ENODEV;
610
611 /*
612 * Allocate the frame buffers:
613 *
614 * rbuff Receive buffer.
615 * xbuff Transmit buffer.
616 */
617 len = dev->mtu * 2;
618
619 /*
620 * allow for arrival of larger UDP packets, even if we say not to
621 * also fixes a bug in which SunOS sends 512-byte packets even with
622 * an MSS of 128
623 */
624 if (len < 576 * 2)
625 len = 576 * 2;
626
627 if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
628 goto norbuff;
629
630 if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
631 goto noxbuff;
632
633 ax->mtu = dev->mtu + 73;
634 ax->buffsize = len;
635 ax->rcount = 0;
636 ax->xleft = 0;
637
638 ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */
639
640 spin_lock_init(&ax->buflock);
641
642 return 0;
643
644 noxbuff:
645 kfree(ax->rbuff);
646
647 norbuff:
648 return -ENOMEM;
649 }
650
651
652 /* Close the low-level part of the AX25 channel. Easy! */
653 static int ax_close(struct net_device *dev)
654 {
655 struct mkiss *ax = netdev_priv(dev);
656
657 if (ax->tty)
658 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
659
660 netif_stop_queue(dev);
661
662 return 0;
663 }
664
665 static const struct header_ops ax_header_ops = {
666 .create = ax_header,
667 .rebuild = ax_rebuild_header,
668 };
669
670 static const struct net_device_ops ax_netdev_ops = {
671 .ndo_open = ax_open_dev,
672 .ndo_stop = ax_close,
673 .ndo_start_xmit = ax_xmit,
674 .ndo_set_mac_address = ax_set_mac_address,
675 };
676
677 static void ax_setup(struct net_device *dev)
678 {
679 /* Finish setting up the DEVICE info. */
680 dev->mtu = AX_MTU;
681 dev->hard_header_len = 0;
682 dev->addr_len = 0;
683 dev->type = ARPHRD_AX25;
684 dev->tx_queue_len = 10;
685 dev->header_ops = &ax_header_ops;
686 dev->netdev_ops = &ax_netdev_ops;
687
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 if (tty->ops->write == NULL)
735 return -EOPNOTSUPP;
736
737 dev = alloc_netdev(sizeof(struct mkiss), "ax%d", ax_setup);
738 if (!dev) {
739 err = -ENOMEM;
740 goto out;
741 }
742
743 ax = netdev_priv(dev);
744 ax->dev = dev;
745
746 spin_lock_init(&ax->buflock);
747 atomic_set(&ax->refcnt, 1);
748 init_MUTEX_LOCKED(&ax->dead_sem);
749
750 ax->tty = tty;
751 tty->disc_data = ax;
752 tty->receive_room = 65535;
753
754 tty_driver_flush_buffer(tty);
755
756 /* Restore default settings */
757 dev->type = ARPHRD_AX25;
758
759 /* Perform the low-level AX25 initialization. */
760 if ((err = ax_open(ax->dev))) {
761 goto out_free_netdev;
762 }
763
764 if (register_netdev(dev))
765 goto out_free_buffers;
766
767 /* after register_netdev() - because else printk smashes the kernel */
768 switch (crc_force) {
769 case 3:
770 ax->crcmode = CRC_MODE_SMACK;
771 printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n",
772 ax->dev->name);
773 break;
774 case 2:
775 ax->crcmode = CRC_MODE_FLEX;
776 printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n",
777 ax->dev->name);
778 break;
779 case 1:
780 ax->crcmode = CRC_MODE_NONE;
781 printk(KERN_INFO "mkiss: %s: crc mode disabled.\n",
782 ax->dev->name);
783 break;
784 case 0:
785 /* fall through */
786 default:
787 crc_force = 0;
788 printk(KERN_INFO "mkiss: %s: crc mode is auto.\n",
789 ax->dev->name);
790 ax->crcmode = CRC_MODE_SMACK_TEST;
791 }
792 ax->crcauto = (crc_force ? 0 : 1);
793
794 netif_start_queue(dev);
795
796 /* Done. We have linked the TTY line to a channel. */
797 return 0;
798
799 out_free_buffers:
800 kfree(ax->rbuff);
801 kfree(ax->xbuff);
802
803 out_free_netdev:
804 free_netdev(dev);
805
806 out:
807 return err;
808 }
809
810 static void mkiss_close(struct tty_struct *tty)
811 {
812 struct mkiss *ax;
813
814 write_lock(&disc_data_lock);
815 ax = tty->disc_data;
816 tty->disc_data = NULL;
817 write_unlock(&disc_data_lock);
818
819 if (!ax)
820 return;
821
822 /*
823 * We have now ensured that nobody can start using ap from now on, but
824 * we have to wait for all existing users to finish.
825 */
826 if (!atomic_dec_and_test(&ax->refcnt))
827 down(&ax->dead_sem);
828
829 unregister_netdev(ax->dev);
830
831 /* Free all AX25 frame buffers. */
832 kfree(ax->rbuff);
833 kfree(ax->xbuff);
834
835 ax->tty = NULL;
836 }
837
838 /* Perform I/O control on an active ax25 channel. */
839 static int mkiss_ioctl(struct tty_struct *tty, struct file *file,
840 unsigned int cmd, unsigned long arg)
841 {
842 struct mkiss *ax = mkiss_get(tty);
843 struct net_device *dev;
844 unsigned int tmp, err;
845
846 /* First make sure we're connected. */
847 if (ax == NULL)
848 return -ENXIO;
849 dev = ax->dev;
850
851 switch (cmd) {
852 case SIOCGIFNAME:
853 err = copy_to_user((void __user *) arg, ax->dev->name,
854 strlen(ax->dev->name) + 1) ? -EFAULT : 0;
855 break;
856
857 case SIOCGIFENCAP:
858 err = put_user(4, (int __user *) arg);
859 break;
860
861 case SIOCSIFENCAP:
862 if (get_user(tmp, (int __user *) arg)) {
863 err = -EFAULT;
864 break;
865 }
866
867 ax->mode = tmp;
868 dev->addr_len = AX25_ADDR_LEN;
869 dev->hard_header_len = AX25_KISS_HEADER_LEN +
870 AX25_MAX_HEADER_LEN + 3;
871 dev->type = ARPHRD_AX25;
872
873 err = 0;
874 break;
875
876 case SIOCSIFHWADDR: {
877 char addr[AX25_ADDR_LEN];
878
879 if (copy_from_user(&addr,
880 (void __user *) arg, AX25_ADDR_LEN)) {
881 err = -EFAULT;
882 break;
883 }
884
885 netif_tx_lock_bh(dev);
886 memcpy(dev->dev_addr, addr, AX25_ADDR_LEN);
887 netif_tx_unlock_bh(dev);
888
889 err = 0;
890 break;
891 }
892 default:
893 err = -ENOIOCTLCMD;
894 }
895
896 mkiss_put(ax);
897
898 return err;
899 }
900
901 /*
902 * Handle the 'receiver data ready' interrupt.
903 * This function is called by the 'tty_io' module in the kernel when
904 * a block of data has been received, which can now be decapsulated
905 * and sent on to the AX.25 layer for further processing.
906 */
907 static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,
908 char *fp, int count)
909 {
910 struct mkiss *ax = mkiss_get(tty);
911
912 if (!ax)
913 return;
914
915 /*
916 * Argh! mtu change time! - costs us the packet part received
917 * at the change
918 */
919 if (ax->mtu != ax->dev->mtu + 73)
920 ax_changedmtu(ax);
921
922 /* Read the characters out of the buffer */
923 while (count--) {
924 if (fp != NULL && *fp++) {
925 if (!test_and_set_bit(AXF_ERROR, &ax->flags))
926 ax->dev->stats.rx_errors++;
927 cp++;
928 continue;
929 }
930
931 kiss_unesc(ax, *cp++);
932 }
933
934 mkiss_put(ax);
935 tty_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->ops->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_ops 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 const char banner[] __initdata = KERN_INFO \
980 "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n";
981 static const 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 status = tty_register_ldisc(N_AX25, &ax_ldisc);
991 if (status != 0)
992 printk(msg_regfail, status);
993
994 return status;
995 }
996
997 static const char msg_unregfail[] __exitdata = KERN_ERR \
998 "mkiss: can't unregister line discipline (err = %d)\n";
999
1000 static void __exit mkiss_exit_driver(void)
1001 {
1002 int ret;
1003
1004 if ((ret = tty_unregister_ldisc(N_AX25)))
1005 printk(msg_unregfail, ret);
1006 }
1007
1008 MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>");
1009 MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs");
1010 module_param(crc_force, int, 0);
1011 MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]");
1012 MODULE_LICENSE("GPL");
1013 MODULE_ALIAS_LDISC(N_AX25);
1014
1015 module_init(mkiss_init_driver);
1016 module_exit(mkiss_exit_driver);
Linux kernel - Deliverables
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