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[NET]: Move hardware header operations out of netdevice.
[mirror_ubuntu-zesty-kernel.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 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,
582 unsigned short type, const void *daddr,
583 const void *saddr, unsigned len)
584 {
585 #ifdef CONFIG_INET
586 if (type != htons(ETH_P_AX25))
587 return ax25_hard_header(skb, dev, type, daddr, saddr, len);
588 #endif
589 return 0;
590 }
591
592
593 static int ax_rebuild_header(struct sk_buff *skb)
594 {
595 #ifdef CONFIG_INET
596 return ax25_rebuild_header(skb);
597 #else
598 return 0;
599 #endif
600 }
601
602 #endif /* CONFIG_{AX25,AX25_MODULE} */
603
604 /* Open the low-level part of the AX25 channel. Easy! */
605 static int ax_open(struct net_device *dev)
606 {
607 struct mkiss *ax = netdev_priv(dev);
608 unsigned long len;
609
610 if (ax->tty == NULL)
611 return -ENODEV;
612
613 /*
614 * Allocate the frame buffers:
615 *
616 * rbuff Receive buffer.
617 * xbuff Transmit buffer.
618 */
619 len = dev->mtu * 2;
620
621 /*
622 * allow for arrival of larger UDP packets, even if we say not to
623 * also fixes a bug in which SunOS sends 512-byte packets even with
624 * an MSS of 128
625 */
626 if (len < 576 * 2)
627 len = 576 * 2;
628
629 if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
630 goto norbuff;
631
632 if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
633 goto noxbuff;
634
635 ax->mtu = dev->mtu + 73;
636 ax->buffsize = len;
637 ax->rcount = 0;
638 ax->xleft = 0;
639
640 ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */
641
642 spin_lock_init(&ax->buflock);
643
644 return 0;
645
646 noxbuff:
647 kfree(ax->rbuff);
648
649 norbuff:
650 return -ENOMEM;
651 }
652
653
654 /* Close the low-level part of the AX25 channel. Easy! */
655 static int ax_close(struct net_device *dev)
656 {
657 struct mkiss *ax = netdev_priv(dev);
658
659 if (ax->tty)
660 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
661
662 netif_stop_queue(dev);
663
664 return 0;
665 }
666
667 static struct net_device_stats *ax_get_stats(struct net_device *dev)
668 {
669 struct mkiss *ax = netdev_priv(dev);
670
671 return &ax->stats;
672 }
673
674 static const struct header_ops ax_header_ops = {
675 .create = ax_header,
676 .rebuild = ax_rebuild_header,
677 };
678
679 static void ax_setup(struct net_device *dev)
680 {
681 /* Finish setting up the DEVICE info. */
682 dev->mtu = AX_MTU;
683 dev->hard_start_xmit = ax_xmit;
684 dev->open = ax_open_dev;
685 dev->stop = ax_close;
686 dev->get_stats = ax_get_stats;
687 dev->set_mac_address = ax_set_mac_address;
688 dev->hard_header_len = 0;
689 dev->addr_len = 0;
690 dev->type = ARPHRD_AX25;
691 dev->tx_queue_len = 10;
692 dev->header_ops = &ax_header_ops;
693
694
695 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
696 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
697
698 dev->flags = IFF_BROADCAST | IFF_MULTICAST;
699 }
700
701 /*
702 * We have a potential race on dereferencing tty->disc_data, because the tty
703 * layer provides no locking at all - thus one cpu could be running
704 * sixpack_receive_buf while another calls sixpack_close, which zeroes
705 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
706 * best way to fix this is to use a rwlock in the tty struct, but for now we
707 * use a single global rwlock for all ttys in ppp line discipline.
708 */
709 static DEFINE_RWLOCK(disc_data_lock);
710
711 static struct mkiss *mkiss_get(struct tty_struct *tty)
712 {
713 struct mkiss *ax;
714
715 read_lock(&disc_data_lock);
716 ax = tty->disc_data;
717 if (ax)
718 atomic_inc(&ax->refcnt);
719 read_unlock(&disc_data_lock);
720
721 return ax;
722 }
723
724 static void mkiss_put(struct mkiss *ax)
725 {
726 if (atomic_dec_and_test(&ax->refcnt))
727 up(&ax->dead_sem);
728 }
729
730 static int crc_force = 0; /* Can be overridden with insmod */
731
732 static int mkiss_open(struct tty_struct *tty)
733 {
734 struct net_device *dev;
735 struct mkiss *ax;
736 int err;
737
738 if (!capable(CAP_NET_ADMIN))
739 return -EPERM;
740
741 dev = alloc_netdev(sizeof(struct mkiss), "ax%d", ax_setup);
742 if (!dev) {
743 err = -ENOMEM;
744 goto out;
745 }
746
747 ax = netdev_priv(dev);
748 ax->dev = dev;
749
750 spin_lock_init(&ax->buflock);
751 atomic_set(&ax->refcnt, 1);
752 init_MUTEX_LOCKED(&ax->dead_sem);
753
754 ax->tty = tty;
755 tty->disc_data = ax;
756 tty->receive_room = 65535;
757
758 if (tty->driver->flush_buffer)
759 tty->driver->flush_buffer(tty);
760
761 /* Restore default settings */
762 dev->type = ARPHRD_AX25;
763
764 /* Perform the low-level AX25 initialization. */
765 if ((err = ax_open(ax->dev))) {
766 goto out_free_netdev;
767 }
768
769 if (register_netdev(dev))
770 goto out_free_buffers;
771
772 /* after register_netdev() - because else printk smashes the kernel */
773 switch (crc_force) {
774 case 3:
775 ax->crcmode = CRC_MODE_SMACK;
776 printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n",
777 ax->dev->name);
778 break;
779 case 2:
780 ax->crcmode = CRC_MODE_FLEX;
781 printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n",
782 ax->dev->name);
783 break;
784 case 1:
785 ax->crcmode = CRC_MODE_NONE;
786 printk(KERN_INFO "mkiss: %s: crc mode disabled.\n",
787 ax->dev->name);
788 break;
789 case 0:
790 /* fall through */
791 default:
792 crc_force = 0;
793 printk(KERN_INFO "mkiss: %s: crc mode is auto.\n",
794 ax->dev->name);
795 ax->crcmode = CRC_MODE_SMACK_TEST;
796 }
797 ax->crcauto = (crc_force ? 0 : 1);
798
799 netif_start_queue(dev);
800
801 /* Done. We have linked the TTY line to a channel. */
802 return 0;
803
804 out_free_buffers:
805 kfree(ax->rbuff);
806 kfree(ax->xbuff);
807
808 out_free_netdev:
809 free_netdev(dev);
810
811 out:
812 return err;
813 }
814
815 static void mkiss_close(struct tty_struct *tty)
816 {
817 struct mkiss *ax;
818
819 write_lock(&disc_data_lock);
820 ax = tty->disc_data;
821 tty->disc_data = NULL;
822 write_unlock(&disc_data_lock);
823
824 if (ax == 0)
825 return;
826
827 /*
828 * We have now ensured that nobody can start using ap from now on, but
829 * we have to wait for all existing users to finish.
830 */
831 if (!atomic_dec_and_test(&ax->refcnt))
832 down(&ax->dead_sem);
833
834 unregister_netdev(ax->dev);
835
836 /* Free all AX25 frame buffers. */
837 kfree(ax->rbuff);
838 kfree(ax->xbuff);
839
840 ax->tty = NULL;
841 }
842
843 /* Perform I/O control on an active ax25 channel. */
844 static int mkiss_ioctl(struct tty_struct *tty, struct file *file,
845 unsigned int cmd, unsigned long arg)
846 {
847 struct mkiss *ax = mkiss_get(tty);
848 struct net_device *dev = ax->dev;
849 unsigned int tmp, err;
850
851 /* First make sure we're connected. */
852 if (ax == NULL)
853 return -ENXIO;
854
855 switch (cmd) {
856 case SIOCGIFNAME:
857 err = copy_to_user((void __user *) arg, ax->dev->name,
858 strlen(ax->dev->name) + 1) ? -EFAULT : 0;
859 break;
860
861 case SIOCGIFENCAP:
862 err = put_user(4, (int __user *) arg);
863 break;
864
865 case SIOCSIFENCAP:
866 if (get_user(tmp, (int __user *) arg)) {
867 err = -EFAULT;
868 break;
869 }
870
871 ax->mode = tmp;
872 dev->addr_len = AX25_ADDR_LEN;
873 dev->hard_header_len = AX25_KISS_HEADER_LEN +
874 AX25_MAX_HEADER_LEN + 3;
875 dev->type = ARPHRD_AX25;
876
877 err = 0;
878 break;
879
880 case SIOCSIFHWADDR: {
881 char addr[AX25_ADDR_LEN];
882
883 if (copy_from_user(&addr,
884 (void __user *) arg, AX25_ADDR_LEN)) {
885 err = -EFAULT;
886 break;
887 }
888
889 netif_tx_lock_bh(dev);
890 memcpy(dev->dev_addr, addr, AX25_ADDR_LEN);
891 netif_tx_unlock_bh(dev);
892
893 err = 0;
894 break;
895 }
896 default:
897 err = -ENOIOCTLCMD;
898 }
899
900 mkiss_put(ax);
901
902 return err;
903 }
904
905 /*
906 * Handle the 'receiver data ready' interrupt.
907 * This function is called by the 'tty_io' module in the kernel when
908 * a block of data has been received, which can now be decapsulated
909 * and sent on to the AX.25 layer for further processing.
910 */
911 static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,
912 char *fp, int count)
913 {
914 struct mkiss *ax = mkiss_get(tty);
915
916 if (!ax)
917 return;
918
919 /*
920 * Argh! mtu change time! - costs us the packet part received
921 * at the change
922 */
923 if (ax->mtu != ax->dev->mtu + 73)
924 ax_changedmtu(ax);
925
926 /* Read the characters out of the buffer */
927 while (count--) {
928 if (fp != NULL && *fp++) {
929 if (!test_and_set_bit(AXF_ERROR, &ax->flags))
930 ax->stats.rx_errors++;
931 cp++;
932 continue;
933 }
934
935 kiss_unesc(ax, *cp++);
936 }
937
938 mkiss_put(ax);
939 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags)
940 && tty->driver->unthrottle)
941 tty->driver->unthrottle(tty);
942 }
943
944 /*
945 * Called by the driver when there's room for more data. If we have
946 * more packets to send, we send them here.
947 */
948 static void mkiss_write_wakeup(struct tty_struct *tty)
949 {
950 struct mkiss *ax = mkiss_get(tty);
951 int actual;
952
953 if (!ax)
954 return;
955
956 if (ax->xleft <= 0) {
957 /* Now serial buffer is almost free & we can start
958 * transmission of another packet
959 */
960 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
961
962 netif_wake_queue(ax->dev);
963 goto out;
964 }
965
966 actual = tty->driver->write(tty, ax->xhead, ax->xleft);
967 ax->xleft -= actual;
968 ax->xhead += actual;
969
970 out:
971 mkiss_put(ax);
972 }
973
974 static struct tty_ldisc ax_ldisc = {
975 .owner = THIS_MODULE,
976 .magic = TTY_LDISC_MAGIC,
977 .name = "mkiss",
978 .open = mkiss_open,
979 .close = mkiss_close,
980 .ioctl = mkiss_ioctl,
981 .receive_buf = mkiss_receive_buf,
982 .write_wakeup = mkiss_write_wakeup
983 };
984
985 static char banner[] __initdata = KERN_INFO \
986 "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n";
987 static char msg_regfail[] __initdata = KERN_ERR \
988 "mkiss: can't register line discipline (err = %d)\n";
989
990 static int __init mkiss_init_driver(void)
991 {
992 int status;
993
994 printk(banner);
995
996 if ((status = tty_register_ldisc(N_AX25, &ax_ldisc)) != 0)
997 printk(msg_regfail);
998
999 return status;
1000 }
1001
1002 static const char msg_unregfail[] __exitdata = KERN_ERR \
1003 "mkiss: can't unregister line discipline (err = %d)\n";
1004
1005 static void __exit mkiss_exit_driver(void)
1006 {
1007 int ret;
1008
1009 if ((ret = tty_unregister_ldisc(N_AX25)))
1010 printk(msg_unregfail, ret);
1011 }
1012
1013 MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>");
1014 MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs");
1015 module_param(crc_force, int, 0);
1016 MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]");
1017 MODULE_LICENSE("GPL");
1018 MODULE_ALIAS_LDISC(N_AX25);
1019
1020 module_init(mkiss_init_driver);
1021 module_exit(mkiss_exit_driver);
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