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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 * Copyright (C) Hans Alblas PE1AYX <hans@esrac.ele.tue.nl>
5 * Copyright (C) 2004, 05 Ralf Baechle DL5RB <ralf@linux-mips.org>
6 * Copyright (C) 2004, 05 Thomas Osterried DL9SAU <thomas@x-berg.in-berlin.de>
7 */
8#include <linux/module.h>
9#include <linux/bitops.h>
10#include <linux/uaccess.h>
11#include <linux/crc16.h>
12#include <linux/string.h>
13#include <linux/mm.h>
14#include <linux/interrupt.h>
15#include <linux/in.h>
16#include <linux/inet.h>
17#include <linux/slab.h>
18#include <linux/tty.h>
19#include <linux/errno.h>
20#include <linux/netdevice.h>
21#include <linux/major.h>
22#include <linux/init.h>
23#include <linux/rtnetlink.h>
24#include <linux/etherdevice.h>
25#include <linux/skbuff.h>
26#include <linux/if_arp.h>
27#include <linux/jiffies.h>
28#include <linux/refcount.h>
29
30#include <net/ax25.h>
31
32#define AX_MTU 236
33
34/* some arch define END as assembly function ending, just undef it */
35#undef END
36/* SLIP/KISS protocol characters. */
37#define END 0300 /* indicates end of frame */
38#define ESC 0333 /* indicates byte stuffing */
39#define ESC_END 0334 /* ESC ESC_END means END 'data' */
40#define ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */
41
42struct mkiss {
43 struct tty_struct *tty; /* ptr to TTY structure */
44 struct net_device *dev; /* easy for intr handling */
45
46 /* These are pointers to the malloc()ed frame buffers. */
47 spinlock_t buflock;/* lock for rbuf and xbuf */
48 unsigned char *rbuff; /* receiver buffer */
49 int rcount; /* received chars counter */
50 unsigned char *xbuff; /* transmitter buffer */
51 unsigned char *xhead; /* pointer to next byte to XMIT */
52 int xleft; /* bytes left in XMIT queue */
53
54 /* Detailed SLIP statistics. */
55 int mtu; /* Our mtu (to spot changes!) */
56 int buffsize; /* Max buffers sizes */
57
58 unsigned long flags; /* Flag values/ mode etc */
59 /* long req'd: used by set_bit --RR */
60#define AXF_INUSE 0 /* Channel in use */
61#define AXF_ESCAPE 1 /* ESC received */
62#define AXF_ERROR 2 /* Parity, etc. error */
63#define AXF_KEEPTEST 3 /* Keepalive test flag */
64#define AXF_OUTWAIT 4 /* is outpacket was flag */
65
66 int mode;
67 int crcmode; /* MW: for FlexNet, SMACK etc. */
68 int crcauto; /* CRC auto mode */
69
70#define CRC_MODE_NONE 0
71#define CRC_MODE_FLEX 1
72#define CRC_MODE_SMACK 2
73#define CRC_MODE_FLEX_TEST 3
74#define CRC_MODE_SMACK_TEST 4
75
76 refcount_t refcnt;
77 struct completion dead;
78};
79
80/*---------------------------------------------------------------------------*/
81
82static const unsigned short crc_flex_table[] = {
83 0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38,
84 0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770,
85 0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9,
86 0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1,
87 0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a,
88 0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672,
89 0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb,
90 0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3,
91 0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c,
92 0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574,
93 0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd,
94 0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5,
95 0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e,
96 0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476,
97 0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf,
98 0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7,
99 0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30,
100 0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378,
101 0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1,
102 0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9,
103 0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32,
104 0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a,
105 0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3,
106 0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb,
107 0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34,
108 0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c,
109 0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5,
110 0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd,
111 0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36,
112 0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e,
113 0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7,
114 0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff
115};
116
117static unsigned short calc_crc_flex(unsigned char *cp, int size)
118{
119 unsigned short crc = 0xffff;
120
121 while (size--)
122 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
123
124 return crc;
125}
126
127static int check_crc_flex(unsigned char *cp, int size)
128{
129 unsigned short crc = 0xffff;
130
131 if (size < 3)
132 return -1;
133
134 while (size--)
135 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
136
137 if ((crc & 0xffff) != 0x7070)
138 return -1;
139
140 return 0;
141}
142
143static int check_crc_16(unsigned char *cp, int size)
144{
145 unsigned short crc = 0x0000;
146
147 if (size < 3)
148 return -1;
149
150 crc = crc16(0, cp, size);
151
152 if (crc != 0x0000)
153 return -1;
154
155 return 0;
156}
157
158/*
159 * Standard encapsulation
160 */
161
162static int kiss_esc(unsigned char *s, unsigned char *d, int len)
163{
164 unsigned char *ptr = d;
165 unsigned char c;
166
167 /*
168 * Send an initial END character to flush out any data that may have
169 * accumulated in the receiver due to line noise.
170 */
171
172 *ptr++ = END;
173
174 while (len-- > 0) {
175 switch (c = *s++) {
176 case END:
177 *ptr++ = ESC;
178 *ptr++ = ESC_END;
179 break;
180 case ESC:
181 *ptr++ = ESC;
182 *ptr++ = ESC_ESC;
183 break;
184 default:
185 *ptr++ = c;
186 break;
187 }
188 }
189
190 *ptr++ = END;
191
192 return ptr - d;
193}
194
195/*
196 * MW:
197 * OK its ugly, but tell me a better solution without copying the
198 * packet to a temporary buffer :-)
199 */
200static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc,
201 int len)
202{
203 unsigned char *ptr = d;
204 unsigned char c=0;
205
206 *ptr++ = END;
207 while (len > 0) {
208 if (len > 2)
209 c = *s++;
210 else if (len > 1)
211 c = crc >> 8;
212 else
213 c = crc & 0xff;
214
215 len--;
216
217 switch (c) {
218 case END:
219 *ptr++ = ESC;
220 *ptr++ = ESC_END;
221 break;
222 case ESC:
223 *ptr++ = ESC;
224 *ptr++ = ESC_ESC;
225 break;
226 default:
227 *ptr++ = c;
228 break;
229 }
230 }
231 *ptr++ = END;
232
233 return ptr - d;
234}
235
236/* Send one completely decapsulated AX.25 packet to the AX.25 layer. */
237static void ax_bump(struct mkiss *ax)
238{
239 struct sk_buff *skb;
240 int count;
241
242 spin_lock_bh(&ax->buflock);
243 if (ax->rbuff[0] > 0x0f) {
244 if (ax->rbuff[0] & 0x80) {
245 if (check_crc_16(ax->rbuff, ax->rcount) < 0) {
246 ax->dev->stats.rx_errors++;
247 spin_unlock_bh(&ax->buflock);
248
249 return;
250 }
251 if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) {
252 printk(KERN_INFO
253 "mkiss: %s: Switching to crc-smack\n",
254 ax->dev->name);
255 ax->crcmode = CRC_MODE_SMACK;
256 }
257 ax->rcount -= 2;
258 *ax->rbuff &= ~0x80;
259 } else if (ax->rbuff[0] & 0x20) {
260 if (check_crc_flex(ax->rbuff, ax->rcount) < 0) {
261 ax->dev->stats.rx_errors++;
262 spin_unlock_bh(&ax->buflock);
263 return;
264 }
265 if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) {
266 printk(KERN_INFO
267 "mkiss: %s: Switching to crc-flexnet\n",
268 ax->dev->name);
269 ax->crcmode = CRC_MODE_FLEX;
270 }
271 ax->rcount -= 2;
272
273 /*
274 * dl9sau bugfix: the trailling two bytes flexnet crc
275 * will not be passed to the kernel. thus we have to
276 * correct the kissparm signature, because it indicates
277 * a crc but there's none
278 */
279 *ax->rbuff &= ~0x20;
280 }
281 }
282
283 count = ax->rcount;
284
285 if ((skb = dev_alloc_skb(count)) == NULL) {
286 printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n",
287 ax->dev->name);
288 ax->dev->stats.rx_dropped++;
289 spin_unlock_bh(&ax->buflock);
290 return;
291 }
292
293 skb_put_data(skb, ax->rbuff, count);
294 skb->protocol = ax25_type_trans(skb, ax->dev);
295 netif_rx(skb);
296 ax->dev->stats.rx_packets++;
297 ax->dev->stats.rx_bytes += count;
298 spin_unlock_bh(&ax->buflock);
299}
300
301static void kiss_unesc(struct mkiss *ax, unsigned char s)
302{
303 switch (s) {
304 case END:
305 /* drop keeptest bit = VSV */
306 if (test_bit(AXF_KEEPTEST, &ax->flags))
307 clear_bit(AXF_KEEPTEST, &ax->flags);
308
309 if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2))
310 ax_bump(ax);
311
312 clear_bit(AXF_ESCAPE, &ax->flags);
313 ax->rcount = 0;
314 return;
315
316 case ESC:
317 set_bit(AXF_ESCAPE, &ax->flags);
318 return;
319 case ESC_ESC:
320 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
321 s = ESC;
322 break;
323 case ESC_END:
324 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
325 s = END;
326 break;
327 }
328
329 spin_lock_bh(&ax->buflock);
330 if (!test_bit(AXF_ERROR, &ax->flags)) {
331 if (ax->rcount < ax->buffsize) {
332 ax->rbuff[ax->rcount++] = s;
333 spin_unlock_bh(&ax->buflock);
334 return;
335 }
336
337 ax->dev->stats.rx_over_errors++;
338 set_bit(AXF_ERROR, &ax->flags);
339 }
340 spin_unlock_bh(&ax->buflock);
341}
342
343static int ax_set_mac_address(struct net_device *dev, void *addr)
344{
345 struct sockaddr_ax25 *sa = addr;
346
347 netif_tx_lock_bh(dev);
348 netif_addr_lock(dev);
349 __dev_addr_set(dev, &sa->sax25_call, AX25_ADDR_LEN);
350 netif_addr_unlock(dev);
351 netif_tx_unlock_bh(dev);
352
353 return 0;
354}
355
356/*---------------------------------------------------------------------------*/
357
358static void ax_changedmtu(struct mkiss *ax)
359{
360 struct net_device *dev = ax->dev;
361 unsigned char *xbuff, *rbuff, *oxbuff, *orbuff;
362 int len;
363
364 len = dev->mtu * 2;
365
366 /*
367 * allow for arrival of larger UDP packets, even if we say not to
368 * also fixes a bug in which SunOS sends 512-byte packets even with
369 * an MSS of 128
370 */
371 if (len < 576 * 2)
372 len = 576 * 2;
373
374 xbuff = kmalloc(len + 4, GFP_ATOMIC);
375 rbuff = kmalloc(len + 4, GFP_ATOMIC);
376
377 if (xbuff == NULL || rbuff == NULL) {
378 printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, "
379 "MTU change cancelled.\n",
380 ax->dev->name);
381 dev->mtu = ax->mtu;
382 kfree(xbuff);
383 kfree(rbuff);
384 return;
385 }
386
387 spin_lock_bh(&ax->buflock);
388
389 oxbuff = ax->xbuff;
390 ax->xbuff = xbuff;
391 orbuff = ax->rbuff;
392 ax->rbuff = rbuff;
393
394 if (ax->xleft) {
395 if (ax->xleft <= len) {
396 memcpy(ax->xbuff, ax->xhead, ax->xleft);
397 } else {
398 ax->xleft = 0;
399 dev->stats.tx_dropped++;
400 }
401 }
402
403 ax->xhead = ax->xbuff;
404
405 if (ax->rcount) {
406 if (ax->rcount <= len) {
407 memcpy(ax->rbuff, orbuff, ax->rcount);
408 } else {
409 ax->rcount = 0;
410 dev->stats.rx_over_errors++;
411 set_bit(AXF_ERROR, &ax->flags);
412 }
413 }
414
415 ax->mtu = dev->mtu + 73;
416 ax->buffsize = len;
417
418 spin_unlock_bh(&ax->buflock);
419
420 kfree(oxbuff);
421 kfree(orbuff);
422}
423
424/* Encapsulate one AX.25 packet and stuff into a TTY queue. */
425static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
426{
427 struct mkiss *ax = netdev_priv(dev);
428 unsigned char *p;
429 int actual, count;
430
431 if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */
432 ax_changedmtu(ax);
433
434 if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */
435 printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name);
436 dev->stats.tx_dropped++;
437 netif_start_queue(dev);
438 return;
439 }
440
441 p = icp;
442
443 spin_lock_bh(&ax->buflock);
444 if ((*p & 0x0f) != 0) {
445 /* Configuration Command (kissparms(1).
446 * Protocol spec says: never append CRC.
447 * This fixes a very old bug in the linux
448 * kiss driver. -- dl9sau */
449 switch (*p & 0xff) {
450 case 0x85:
451 /* command from userspace especially for us,
452 * not for delivery to the tnc */
453 if (len > 1) {
454 int cmd = (p[1] & 0xff);
455 switch(cmd) {
456 case 3:
457 ax->crcmode = CRC_MODE_SMACK;
458 break;
459 case 2:
460 ax->crcmode = CRC_MODE_FLEX;
461 break;
462 case 1:
463 ax->crcmode = CRC_MODE_NONE;
464 break;
465 case 0:
466 default:
467 ax->crcmode = CRC_MODE_SMACK_TEST;
468 cmd = 0;
469 }
470 ax->crcauto = (cmd ? 0 : 1);
471 printk(KERN_INFO "mkiss: %s: crc mode set to %d\n",
472 ax->dev->name, cmd);
473 }
474 spin_unlock_bh(&ax->buflock);
475 netif_start_queue(dev);
476
477 return;
478 default:
479 count = kiss_esc(p, ax->xbuff, len);
480 }
481 } else {
482 unsigned short crc;
483 switch (ax->crcmode) {
484 case CRC_MODE_SMACK_TEST:
485 ax->crcmode = CRC_MODE_FLEX_TEST;
486 printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name);
487 fallthrough;
488 case CRC_MODE_SMACK:
489 *p |= 0x80;
490 crc = swab16(crc16(0, p, len));
491 count = kiss_esc_crc(p, ax->xbuff, crc, len+2);
492 break;
493 case CRC_MODE_FLEX_TEST:
494 ax->crcmode = CRC_MODE_NONE;
495 printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name);
496 fallthrough;
497 case CRC_MODE_FLEX:
498 *p |= 0x20;
499 crc = calc_crc_flex(p, len);
500 count = kiss_esc_crc(p, ax->xbuff, crc, len+2);
501 break;
502
503 default:
504 count = kiss_esc(p, ax->xbuff, len);
505 }
506 }
507 spin_unlock_bh(&ax->buflock);
508
509 set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
510 actual = ax->tty->ops->write(ax->tty, ax->xbuff, count);
511 dev->stats.tx_packets++;
512 dev->stats.tx_bytes += actual;
513
514 netif_trans_update(ax->dev);
515 ax->xleft = count - actual;
516 ax->xhead = ax->xbuff + actual;
517}
518
519/* Encapsulate an AX.25 packet and kick it into a TTY queue. */
520static netdev_tx_t ax_xmit(struct sk_buff *skb, struct net_device *dev)
521{
522 struct mkiss *ax = netdev_priv(dev);
523
524 if (skb->protocol == htons(ETH_P_IP))
525 return ax25_ip_xmit(skb);
526
527 if (!netif_running(dev)) {
528 printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name);
529 return NETDEV_TX_BUSY;
530 }
531
532 if (netif_queue_stopped(dev)) {
533 /*
534 * May be we must check transmitter timeout here ?
535 * 14 Oct 1994 Dmitry Gorodchanin.
536 */
537 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) {
538 /* 20 sec timeout not reached */
539 return NETDEV_TX_BUSY;
540 }
541
542 printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name,
543 (tty_chars_in_buffer(ax->tty) || ax->xleft) ?
544 "bad line quality" : "driver error");
545
546 ax->xleft = 0;
547 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
548 netif_start_queue(dev);
549 }
550
551 /* We were not busy, so we are now... :-) */
552 netif_stop_queue(dev);
553 ax_encaps(dev, skb->data, skb->len);
554 kfree_skb(skb);
555
556 return NETDEV_TX_OK;
557}
558
559static int ax_open_dev(struct net_device *dev)
560{
561 struct mkiss *ax = netdev_priv(dev);
562
563 if (ax->tty == NULL)
564 return -ENODEV;
565
566 return 0;
567}
568
569/* Open the low-level part of the AX25 channel. Easy! */
570static int ax_open(struct net_device *dev)
571{
572 struct mkiss *ax = netdev_priv(dev);
573 unsigned long len;
574
575 if (ax->tty == NULL)
576 return -ENODEV;
577
578 /*
579 * Allocate the frame buffers:
580 *
581 * rbuff Receive buffer.
582 * xbuff Transmit buffer.
583 */
584 len = dev->mtu * 2;
585
586 /*
587 * allow for arrival of larger UDP packets, even if we say not to
588 * also fixes a bug in which SunOS sends 512-byte packets even with
589 * an MSS of 128
590 */
591 if (len < 576 * 2)
592 len = 576 * 2;
593
594 if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
595 goto norbuff;
596
597 if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
598 goto noxbuff;
599
600 ax->mtu = dev->mtu + 73;
601 ax->buffsize = len;
602 ax->rcount = 0;
603 ax->xleft = 0;
604
605 ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */
606
607 spin_lock_init(&ax->buflock);
608
609 return 0;
610
611noxbuff:
612 kfree(ax->rbuff);
613
614norbuff:
615 return -ENOMEM;
616}
617
618
619/* Close the low-level part of the AX25 channel. Easy! */
620static int ax_close(struct net_device *dev)
621{
622 struct mkiss *ax = netdev_priv(dev);
623
624 if (ax->tty)
625 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
626
627 netif_stop_queue(dev);
628
629 return 0;
630}
631
632static const struct net_device_ops ax_netdev_ops = {
633 .ndo_open = ax_open_dev,
634 .ndo_stop = ax_close,
635 .ndo_start_xmit = ax_xmit,
636 .ndo_set_mac_address = ax_set_mac_address,
637};
638
639static void ax_setup(struct net_device *dev)
640{
641 /* Finish setting up the DEVICE info. */
642 dev->mtu = AX_MTU;
643 dev->hard_header_len = AX25_MAX_HEADER_LEN;
644 dev->addr_len = AX25_ADDR_LEN;
645 dev->type = ARPHRD_AX25;
646 dev->tx_queue_len = 10;
647 dev->header_ops = &ax25_header_ops;
648 dev->netdev_ops = &ax_netdev_ops;
649
650
651 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
652 dev_addr_set(dev, (u8 *)&ax25_defaddr);
653
654 dev->flags = IFF_BROADCAST | IFF_MULTICAST;
655}
656
657/*
658 * We have a potential race on dereferencing tty->disc_data, because the tty
659 * layer provides no locking at all - thus one cpu could be running
660 * sixpack_receive_buf while another calls sixpack_close, which zeroes
661 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
662 * best way to fix this is to use a rwlock in the tty struct, but for now we
663 * use a single global rwlock for all ttys in ppp line discipline.
664 */
665static DEFINE_RWLOCK(disc_data_lock);
666
667static struct mkiss *mkiss_get(struct tty_struct *tty)
668{
669 struct mkiss *ax;
670
671 read_lock(&disc_data_lock);
672 ax = tty->disc_data;
673 if (ax)
674 refcount_inc(&ax->refcnt);
675 read_unlock(&disc_data_lock);
676
677 return ax;
678}
679
680static void mkiss_put(struct mkiss *ax)
681{
682 if (refcount_dec_and_test(&ax->refcnt))
683 complete(&ax->dead);
684}
685
686static int crc_force = 0; /* Can be overridden with insmod */
687
688static int mkiss_open(struct tty_struct *tty)
689{
690 struct net_device *dev;
691 struct mkiss *ax;
692 int err;
693
694 if (!capable(CAP_NET_ADMIN))
695 return -EPERM;
696 if (tty->ops->write == NULL)
697 return -EOPNOTSUPP;
698
699 dev = alloc_netdev(sizeof(struct mkiss), "ax%d", NET_NAME_UNKNOWN,
700 ax_setup);
701 if (!dev) {
702 err = -ENOMEM;
703 goto out;
704 }
705
706 ax = netdev_priv(dev);
707 ax->dev = dev;
708
709 spin_lock_init(&ax->buflock);
710 refcount_set(&ax->refcnt, 1);
711 init_completion(&ax->dead);
712
713 ax->tty = tty;
714 tty->disc_data = ax;
715 tty->receive_room = 65535;
716
717 tty_driver_flush_buffer(tty);
718
719 /* Restore default settings */
720 dev->type = ARPHRD_AX25;
721
722 /* Perform the low-level AX25 initialization. */
723 err = ax_open(ax->dev);
724 if (err)
725 goto out_free_netdev;
726
727 err = register_netdev(dev);
728 if (err)
729 goto out_free_buffers;
730
731 /* after register_netdev() - because else printk smashes the kernel */
732 switch (crc_force) {
733 case 3:
734 ax->crcmode = CRC_MODE_SMACK;
735 printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n",
736 ax->dev->name);
737 break;
738 case 2:
739 ax->crcmode = CRC_MODE_FLEX;
740 printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n",
741 ax->dev->name);
742 break;
743 case 1:
744 ax->crcmode = CRC_MODE_NONE;
745 printk(KERN_INFO "mkiss: %s: crc mode disabled.\n",
746 ax->dev->name);
747 break;
748 case 0:
749 default:
750 crc_force = 0;
751 printk(KERN_INFO "mkiss: %s: crc mode is auto.\n",
752 ax->dev->name);
753 ax->crcmode = CRC_MODE_SMACK_TEST;
754 }
755 ax->crcauto = (crc_force ? 0 : 1);
756
757 netif_start_queue(dev);
758
759 /* Done. We have linked the TTY line to a channel. */
760 return 0;
761
762out_free_buffers:
763 kfree(ax->rbuff);
764 kfree(ax->xbuff);
765
766out_free_netdev:
767 free_netdev(dev);
768
769out:
770 return err;
771}
772
773static void mkiss_close(struct tty_struct *tty)
774{
775 struct mkiss *ax;
776
777 write_lock_irq(&disc_data_lock);
778 ax = tty->disc_data;
779 tty->disc_data = NULL;
780 write_unlock_irq(&disc_data_lock);
781
782 if (!ax)
783 return;
784
785 /*
786 * We have now ensured that nobody can start using ap from now on, but
787 * we have to wait for all existing users to finish.
788 */
789 if (!refcount_dec_and_test(&ax->refcnt))
790 wait_for_completion(&ax->dead);
791 /*
792 * Halt the transmit queue so that a new transmit cannot scribble
793 * on our buffers
794 */
795 netif_stop_queue(ax->dev);
796
797 unregister_netdev(ax->dev);
798
799 /* Free all AX25 frame buffers after unreg. */
800 kfree(ax->rbuff);
801 kfree(ax->xbuff);
802
803 ax->tty = NULL;
804
805 free_netdev(ax->dev);
806}
807
808/* Perform I/O control on an active ax25 channel. */
809static int mkiss_ioctl(struct tty_struct *tty, unsigned int cmd,
810 unsigned long arg)
811{
812 struct mkiss *ax = mkiss_get(tty);
813 struct net_device *dev;
814 unsigned int tmp, err;
815
816 /* First make sure we're connected. */
817 if (ax == NULL)
818 return -ENXIO;
819 dev = ax->dev;
820
821 switch (cmd) {
822 case SIOCGIFNAME:
823 err = copy_to_user((void __user *) arg, ax->dev->name,
824 strlen(ax->dev->name) + 1) ? -EFAULT : 0;
825 break;
826
827 case SIOCGIFENCAP:
828 err = put_user(4, (int __user *) arg);
829 break;
830
831 case SIOCSIFENCAP:
832 if (get_user(tmp, (int __user *) arg)) {
833 err = -EFAULT;
834 break;
835 }
836
837 ax->mode = tmp;
838 dev->addr_len = AX25_ADDR_LEN;
839 dev->hard_header_len = AX25_KISS_HEADER_LEN +
840 AX25_MAX_HEADER_LEN + 3;
841 dev->type = ARPHRD_AX25;
842
843 err = 0;
844 break;
845
846 case SIOCSIFHWADDR: {
847 char addr[AX25_ADDR_LEN];
848
849 if (copy_from_user(&addr,
850 (void __user *) arg, AX25_ADDR_LEN)) {
851 err = -EFAULT;
852 break;
853 }
854
855 netif_tx_lock_bh(dev);
856 __dev_addr_set(dev, addr, AX25_ADDR_LEN);
857 netif_tx_unlock_bh(dev);
858
859 err = 0;
860 break;
861 }
862 default:
863 err = -ENOIOCTLCMD;
864 }
865
866 mkiss_put(ax);
867
868 return err;
869}
870
871/*
872 * Handle the 'receiver data ready' interrupt.
873 * This function is called by the 'tty_io' module in the kernel when
874 * a block of data has been received, which can now be decapsulated
875 * and sent on to the AX.25 layer for further processing.
876 */
877static void mkiss_receive_buf(struct tty_struct *tty, const u8 *cp,
878 const u8 *fp, size_t count)
879{
880 struct mkiss *ax = mkiss_get(tty);
881
882 if (!ax)
883 return;
884
885 /*
886 * Argh! mtu change time! - costs us the packet part received
887 * at the change
888 */
889 if (ax->mtu != ax->dev->mtu + 73)
890 ax_changedmtu(ax);
891
892 /* Read the characters out of the buffer */
893 while (count--) {
894 if (fp != NULL && *fp++) {
895 if (!test_and_set_bit(AXF_ERROR, &ax->flags))
896 ax->dev->stats.rx_errors++;
897 cp++;
898 continue;
899 }
900
901 kiss_unesc(ax, *cp++);
902 }
903
904 mkiss_put(ax);
905 tty_unthrottle(tty);
906}
907
908/*
909 * Called by the driver when there's room for more data. If we have
910 * more packets to send, we send them here.
911 */
912static void mkiss_write_wakeup(struct tty_struct *tty)
913{
914 struct mkiss *ax = mkiss_get(tty);
915 int actual;
916
917 if (!ax)
918 return;
919
920 if (ax->xleft <= 0) {
921 /* Now serial buffer is almost free & we can start
922 * transmission of another packet
923 */
924 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
925
926 netif_wake_queue(ax->dev);
927 goto out;
928 }
929
930 actual = tty->ops->write(tty, ax->xhead, ax->xleft);
931 ax->xleft -= actual;
932 ax->xhead += actual;
933
934out:
935 mkiss_put(ax);
936}
937
938static struct tty_ldisc_ops ax_ldisc = {
939 .owner = THIS_MODULE,
940 .num = N_AX25,
941 .name = "mkiss",
942 .open = mkiss_open,
943 .close = mkiss_close,
944 .ioctl = mkiss_ioctl,
945 .receive_buf = mkiss_receive_buf,
946 .write_wakeup = mkiss_write_wakeup
947};
948
949static const char banner[] __initconst = KERN_INFO \
950 "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n";
951static const char msg_regfail[] __initconst = KERN_ERR \
952 "mkiss: can't register line discipline (err = %d)\n";
953
954static int __init mkiss_init_driver(void)
955{
956 int status;
957
958 printk(banner);
959
960 status = tty_register_ldisc(&ax_ldisc);
961 if (status != 0)
962 printk(msg_regfail, status);
963
964 return status;
965}
966
967static void __exit mkiss_exit_driver(void)
968{
969 tty_unregister_ldisc(&ax_ldisc);
970}
971
972MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>");
973MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs");
974module_param(crc_force, int, 0);
975MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]");
976MODULE_LICENSE("GPL");
977MODULE_ALIAS_LDISC(N_AX25);
978
979module_init(mkiss_init_driver);
980module_exit(mkiss_exit_driver);
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 <linux/bitops.h>
21#include <asm/uaccess.h>
22#include <linux/crc16.h>
23#include <linux/string.h>
24#include <linux/mm.h>
25#include <linux/interrupt.h>
26#include <linux/in.h>
27#include <linux/inet.h>
28#include <linux/slab.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#include <linux/compat.h>
40
41#include <net/ax25.h>
42
43#define AX_MTU 236
44
45/* SLIP/KISS protocol characters. */
46#define END 0300 /* indicates end of frame */
47#define ESC 0333 /* indicates byte stuffing */
48#define ESC_END 0334 /* ESC ESC_END means END 'data' */
49#define ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */
50
51struct mkiss {
52 struct tty_struct *tty; /* ptr to TTY structure */
53 struct net_device *dev; /* easy for intr handling */
54
55 /* These are pointers to the malloc()ed frame buffers. */
56 spinlock_t buflock;/* lock for rbuf and xbuf */
57 unsigned char *rbuff; /* receiver buffer */
58 int rcount; /* received chars counter */
59 unsigned char *xbuff; /* transmitter buffer */
60 unsigned char *xhead; /* pointer to next byte to XMIT */
61 int xleft; /* bytes left in XMIT queue */
62
63 /* Detailed SLIP statistics. */
64 int mtu; /* Our mtu (to spot changes!) */
65 int buffsize; /* Max buffers sizes */
66
67 unsigned long flags; /* Flag values/ mode etc */
68 /* long req'd: used by set_bit --RR */
69#define AXF_INUSE 0 /* Channel in use */
70#define AXF_ESCAPE 1 /* ESC received */
71#define AXF_ERROR 2 /* Parity, etc. error */
72#define AXF_KEEPTEST 3 /* Keepalive test flag */
73#define AXF_OUTWAIT 4 /* is outpacket was flag */
74
75 int mode;
76 int crcmode; /* MW: for FlexNet, SMACK etc. */
77 int crcauto; /* CRC auto mode */
78
79#define CRC_MODE_NONE 0
80#define CRC_MODE_FLEX 1
81#define CRC_MODE_SMACK 2
82#define CRC_MODE_FLEX_TEST 3
83#define CRC_MODE_SMACK_TEST 4
84
85 atomic_t refcnt;
86 struct semaphore dead_sem;
87};
88
89/*---------------------------------------------------------------------------*/
90
91static const unsigned short crc_flex_table[] = {
92 0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38,
93 0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770,
94 0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9,
95 0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1,
96 0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a,
97 0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672,
98 0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb,
99 0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3,
100 0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c,
101 0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574,
102 0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd,
103 0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5,
104 0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e,
105 0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476,
106 0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf,
107 0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7,
108 0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30,
109 0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378,
110 0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1,
111 0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9,
112 0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32,
113 0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a,
114 0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3,
115 0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb,
116 0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34,
117 0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c,
118 0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5,
119 0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd,
120 0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36,
121 0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e,
122 0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7,
123 0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff
124};
125
126static unsigned short calc_crc_flex(unsigned char *cp, int size)
127{
128 unsigned short crc = 0xffff;
129
130 while (size--)
131 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
132
133 return crc;
134}
135
136static int check_crc_flex(unsigned char *cp, int size)
137{
138 unsigned short crc = 0xffff;
139
140 if (size < 3)
141 return -1;
142
143 while (size--)
144 crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff];
145
146 if ((crc & 0xffff) != 0x7070)
147 return -1;
148
149 return 0;
150}
151
152static int check_crc_16(unsigned char *cp, int size)
153{
154 unsigned short crc = 0x0000;
155
156 if (size < 3)
157 return -1;
158
159 crc = crc16(0, cp, size);
160
161 if (crc != 0x0000)
162 return -1;
163
164 return 0;
165}
166
167/*
168 * Standard encapsulation
169 */
170
171static int kiss_esc(unsigned char *s, unsigned char *d, int len)
172{
173 unsigned char *ptr = d;
174 unsigned char c;
175
176 /*
177 * Send an initial END character to flush out any data that may have
178 * accumulated in the receiver due to line noise.
179 */
180
181 *ptr++ = END;
182
183 while (len-- > 0) {
184 switch (c = *s++) {
185 case END:
186 *ptr++ = ESC;
187 *ptr++ = ESC_END;
188 break;
189 case ESC:
190 *ptr++ = ESC;
191 *ptr++ = ESC_ESC;
192 break;
193 default:
194 *ptr++ = c;
195 break;
196 }
197 }
198
199 *ptr++ = END;
200
201 return ptr - d;
202}
203
204/*
205 * MW:
206 * OK its ugly, but tell me a better solution without copying the
207 * packet to a temporary buffer :-)
208 */
209static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc,
210 int len)
211{
212 unsigned char *ptr = d;
213 unsigned char c=0;
214
215 *ptr++ = END;
216 while (len > 0) {
217 if (len > 2)
218 c = *s++;
219 else if (len > 1)
220 c = crc >> 8;
221 else if (len > 0)
222 c = crc & 0xff;
223
224 len--;
225
226 switch (c) {
227 case END:
228 *ptr++ = ESC;
229 *ptr++ = ESC_END;
230 break;
231 case ESC:
232 *ptr++ = ESC;
233 *ptr++ = ESC_ESC;
234 break;
235 default:
236 *ptr++ = c;
237 break;
238 }
239 }
240 *ptr++ = END;
241
242 return ptr - d;
243}
244
245/* Send one completely decapsulated AX.25 packet to the AX.25 layer. */
246static void ax_bump(struct mkiss *ax)
247{
248 struct sk_buff *skb;
249 int count;
250
251 spin_lock_bh(&ax->buflock);
252 if (ax->rbuff[0] > 0x0f) {
253 if (ax->rbuff[0] & 0x80) {
254 if (check_crc_16(ax->rbuff, ax->rcount) < 0) {
255 ax->dev->stats.rx_errors++;
256 spin_unlock_bh(&ax->buflock);
257
258 return;
259 }
260 if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) {
261 printk(KERN_INFO
262 "mkiss: %s: Switching to crc-smack\n",
263 ax->dev->name);
264 ax->crcmode = CRC_MODE_SMACK;
265 }
266 ax->rcount -= 2;
267 *ax->rbuff &= ~0x80;
268 } else if (ax->rbuff[0] & 0x20) {
269 if (check_crc_flex(ax->rbuff, ax->rcount) < 0) {
270 ax->dev->stats.rx_errors++;
271 spin_unlock_bh(&ax->buflock);
272 return;
273 }
274 if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) {
275 printk(KERN_INFO
276 "mkiss: %s: Switching to crc-flexnet\n",
277 ax->dev->name);
278 ax->crcmode = CRC_MODE_FLEX;
279 }
280 ax->rcount -= 2;
281
282 /*
283 * dl9sau bugfix: the trailling two bytes flexnet crc
284 * will not be passed to the kernel. thus we have to
285 * correct the kissparm signature, because it indicates
286 * a crc but there's none
287 */
288 *ax->rbuff &= ~0x20;
289 }
290 }
291
292 count = ax->rcount;
293
294 if ((skb = dev_alloc_skb(count)) == NULL) {
295 printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n",
296 ax->dev->name);
297 ax->dev->stats.rx_dropped++;
298 spin_unlock_bh(&ax->buflock);
299 return;
300 }
301
302 memcpy(skb_put(skb,count), ax->rbuff, count);
303 skb->protocol = ax25_type_trans(skb, ax->dev);
304 netif_rx(skb);
305 ax->dev->stats.rx_packets++;
306 ax->dev->stats.rx_bytes += count;
307 spin_unlock_bh(&ax->buflock);
308}
309
310static void kiss_unesc(struct mkiss *ax, unsigned char s)
311{
312 switch (s) {
313 case END:
314 /* drop keeptest bit = VSV */
315 if (test_bit(AXF_KEEPTEST, &ax->flags))
316 clear_bit(AXF_KEEPTEST, &ax->flags);
317
318 if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2))
319 ax_bump(ax);
320
321 clear_bit(AXF_ESCAPE, &ax->flags);
322 ax->rcount = 0;
323 return;
324
325 case ESC:
326 set_bit(AXF_ESCAPE, &ax->flags);
327 return;
328 case ESC_ESC:
329 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
330 s = ESC;
331 break;
332 case ESC_END:
333 if (test_and_clear_bit(AXF_ESCAPE, &ax->flags))
334 s = END;
335 break;
336 }
337
338 spin_lock_bh(&ax->buflock);
339 if (!test_bit(AXF_ERROR, &ax->flags)) {
340 if (ax->rcount < ax->buffsize) {
341 ax->rbuff[ax->rcount++] = s;
342 spin_unlock_bh(&ax->buflock);
343 return;
344 }
345
346 ax->dev->stats.rx_over_errors++;
347 set_bit(AXF_ERROR, &ax->flags);
348 }
349 spin_unlock_bh(&ax->buflock);
350}
351
352static int ax_set_mac_address(struct net_device *dev, void *addr)
353{
354 struct sockaddr_ax25 *sa = addr;
355
356 netif_tx_lock_bh(dev);
357 netif_addr_lock(dev);
358 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
359 netif_addr_unlock(dev);
360 netif_tx_unlock_bh(dev);
361
362 return 0;
363}
364
365/*---------------------------------------------------------------------------*/
366
367static void ax_changedmtu(struct mkiss *ax)
368{
369 struct net_device *dev = ax->dev;
370 unsigned char *xbuff, *rbuff, *oxbuff, *orbuff;
371 int len;
372
373 len = dev->mtu * 2;
374
375 /*
376 * allow for arrival of larger UDP packets, even if we say not to
377 * also fixes a bug in which SunOS sends 512-byte packets even with
378 * an MSS of 128
379 */
380 if (len < 576 * 2)
381 len = 576 * 2;
382
383 xbuff = kmalloc(len + 4, GFP_ATOMIC);
384 rbuff = kmalloc(len + 4, GFP_ATOMIC);
385
386 if (xbuff == NULL || rbuff == NULL) {
387 printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, "
388 "MTU change cancelled.\n",
389 ax->dev->name);
390 dev->mtu = ax->mtu;
391 kfree(xbuff);
392 kfree(rbuff);
393 return;
394 }
395
396 spin_lock_bh(&ax->buflock);
397
398 oxbuff = ax->xbuff;
399 ax->xbuff = xbuff;
400 orbuff = ax->rbuff;
401 ax->rbuff = rbuff;
402
403 if (ax->xleft) {
404 if (ax->xleft <= len) {
405 memcpy(ax->xbuff, ax->xhead, ax->xleft);
406 } else {
407 ax->xleft = 0;
408 dev->stats.tx_dropped++;
409 }
410 }
411
412 ax->xhead = ax->xbuff;
413
414 if (ax->rcount) {
415 if (ax->rcount <= len) {
416 memcpy(ax->rbuff, orbuff, ax->rcount);
417 } else {
418 ax->rcount = 0;
419 dev->stats.rx_over_errors++;
420 set_bit(AXF_ERROR, &ax->flags);
421 }
422 }
423
424 ax->mtu = dev->mtu + 73;
425 ax->buffsize = len;
426
427 spin_unlock_bh(&ax->buflock);
428
429 kfree(oxbuff);
430 kfree(orbuff);
431}
432
433/* Encapsulate one AX.25 packet and stuff into a TTY queue. */
434static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
435{
436 struct mkiss *ax = netdev_priv(dev);
437 unsigned char *p;
438 int actual, count;
439
440 if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */
441 ax_changedmtu(ax);
442
443 if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */
444 len = ax->mtu;
445 printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name);
446 dev->stats.tx_dropped++;
447 netif_start_queue(dev);
448 return;
449 }
450
451 p = icp;
452
453 spin_lock_bh(&ax->buflock);
454 if ((*p & 0x0f) != 0) {
455 /* Configuration Command (kissparms(1).
456 * Protocol spec says: never append CRC.
457 * This fixes a very old bug in the linux
458 * kiss driver. -- dl9sau */
459 switch (*p & 0xff) {
460 case 0x85:
461 /* command from userspace especially for us,
462 * not for delivery to the tnc */
463 if (len > 1) {
464 int cmd = (p[1] & 0xff);
465 switch(cmd) {
466 case 3:
467 ax->crcmode = CRC_MODE_SMACK;
468 break;
469 case 2:
470 ax->crcmode = CRC_MODE_FLEX;
471 break;
472 case 1:
473 ax->crcmode = CRC_MODE_NONE;
474 break;
475 case 0:
476 default:
477 ax->crcmode = CRC_MODE_SMACK_TEST;
478 cmd = 0;
479 }
480 ax->crcauto = (cmd ? 0 : 1);
481 printk(KERN_INFO "mkiss: %s: crc mode %s %d\n", ax->dev->name, (len) ? "set to" : "is", cmd);
482 }
483 spin_unlock_bh(&ax->buflock);
484 netif_start_queue(dev);
485
486 return;
487 default:
488 count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
489 }
490 } else {
491 unsigned short crc;
492 switch (ax->crcmode) {
493 case CRC_MODE_SMACK_TEST:
494 ax->crcmode = CRC_MODE_FLEX_TEST;
495 printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name);
496 // fall through
497 case CRC_MODE_SMACK:
498 *p |= 0x80;
499 crc = swab16(crc16(0, p, len));
500 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2);
501 break;
502 case CRC_MODE_FLEX_TEST:
503 ax->crcmode = CRC_MODE_NONE;
504 printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name);
505 // fall through
506 case CRC_MODE_FLEX:
507 *p |= 0x20;
508 crc = calc_crc_flex(p, len);
509 count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2);
510 break;
511
512 default:
513 count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
514 }
515 }
516 spin_unlock_bh(&ax->buflock);
517
518 set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
519 actual = ax->tty->ops->write(ax->tty, ax->xbuff, count);
520 dev->stats.tx_packets++;
521 dev->stats.tx_bytes += actual;
522
523 ax->dev->trans_start = jiffies;
524 ax->xleft = count - actual;
525 ax->xhead = ax->xbuff + actual;
526}
527
528/* Encapsulate an AX.25 packet and kick it into a TTY queue. */
529static netdev_tx_t ax_xmit(struct sk_buff *skb, struct net_device *dev)
530{
531 struct mkiss *ax = netdev_priv(dev);
532
533 if (!netif_running(dev)) {
534 printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name);
535 return NETDEV_TX_BUSY;
536 }
537
538 if (netif_queue_stopped(dev)) {
539 /*
540 * May be we must check transmitter timeout here ?
541 * 14 Oct 1994 Dmitry Gorodchanin.
542 */
543 if (time_before(jiffies, dev->trans_start + 20 * HZ)) {
544 /* 20 sec timeout not reached */
545 return NETDEV_TX_BUSY;
546 }
547
548 printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name,
549 (tty_chars_in_buffer(ax->tty) || ax->xleft) ?
550 "bad line quality" : "driver error");
551
552 ax->xleft = 0;
553 clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
554 netif_start_queue(dev);
555 }
556
557 /* We were not busy, so we are now... :-) */
558 if (skb != NULL) {
559 netif_stop_queue(dev);
560 ax_encaps(dev, skb->data, skb->len);
561 kfree_skb(skb);
562 }
563
564 return NETDEV_TX_OK;
565}
566
567static int ax_open_dev(struct net_device *dev)
568{
569 struct mkiss *ax = netdev_priv(dev);
570
571 if (ax->tty == NULL)
572 return -ENODEV;
573
574 return 0;
575}
576
577#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
578
579/* Return the frame type ID */
580static int ax_header(struct sk_buff *skb, struct net_device *dev,
581 unsigned short type, const void *daddr,
582 const void *saddr, unsigned len)
583{
584#ifdef CONFIG_INET
585 if (type != ETH_P_AX25)
586 return ax25_hard_header(skb, dev, type, daddr, saddr, len);
587#endif
588 return 0;
589}
590
591
592static 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! */
604static 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
645noxbuff:
646 kfree(ax->rbuff);
647
648norbuff:
649 return -ENOMEM;
650}
651
652
653/* Close the low-level part of the AX25 channel. Easy! */
654static 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
666static const struct header_ops ax_header_ops = {
667 .create = ax_header,
668 .rebuild = ax_rebuild_header,
669};
670
671static const struct net_device_ops ax_netdev_ops = {
672 .ndo_open = ax_open_dev,
673 .ndo_stop = ax_close,
674 .ndo_start_xmit = ax_xmit,
675 .ndo_set_mac_address = ax_set_mac_address,
676};
677
678static void ax_setup(struct net_device *dev)
679{
680 /* Finish setting up the DEVICE info. */
681 dev->mtu = AX_MTU;
682 dev->hard_header_len = 0;
683 dev->addr_len = 0;
684 dev->type = ARPHRD_AX25;
685 dev->tx_queue_len = 10;
686 dev->header_ops = &ax_header_ops;
687 dev->netdev_ops = &ax_netdev_ops;
688
689
690 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
691 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
692
693 dev->flags = IFF_BROADCAST | IFF_MULTICAST;
694}
695
696/*
697 * We have a potential race on dereferencing tty->disc_data, because the tty
698 * layer provides no locking at all - thus one cpu could be running
699 * sixpack_receive_buf while another calls sixpack_close, which zeroes
700 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
701 * best way to fix this is to use a rwlock in the tty struct, but for now we
702 * use a single global rwlock for all ttys in ppp line discipline.
703 */
704static DEFINE_RWLOCK(disc_data_lock);
705
706static struct mkiss *mkiss_get(struct tty_struct *tty)
707{
708 struct mkiss *ax;
709
710 read_lock(&disc_data_lock);
711 ax = tty->disc_data;
712 if (ax)
713 atomic_inc(&ax->refcnt);
714 read_unlock(&disc_data_lock);
715
716 return ax;
717}
718
719static void mkiss_put(struct mkiss *ax)
720{
721 if (atomic_dec_and_test(&ax->refcnt))
722 up(&ax->dead_sem);
723}
724
725static int crc_force = 0; /* Can be overridden with insmod */
726
727static int mkiss_open(struct tty_struct *tty)
728{
729 struct net_device *dev;
730 struct mkiss *ax;
731 int err;
732
733 if (!capable(CAP_NET_ADMIN))
734 return -EPERM;
735 if (tty->ops->write == NULL)
736 return -EOPNOTSUPP;
737
738 dev = alloc_netdev(sizeof(struct mkiss), "ax%d", ax_setup);
739 if (!dev) {
740 err = -ENOMEM;
741 goto out;
742 }
743
744 ax = netdev_priv(dev);
745 ax->dev = dev;
746
747 spin_lock_init(&ax->buflock);
748 atomic_set(&ax->refcnt, 1);
749 sema_init(&ax->dead_sem, 0);
750
751 ax->tty = tty;
752 tty->disc_data = ax;
753 tty->receive_room = 65535;
754
755 tty_driver_flush_buffer(tty);
756
757 /* Restore default settings */
758 dev->type = ARPHRD_AX25;
759
760 /* Perform the low-level AX25 initialization. */
761 if ((err = ax_open(ax->dev))) {
762 goto out_free_netdev;
763 }
764
765 if (register_netdev(dev))
766 goto out_free_buffers;
767
768 /* after register_netdev() - because else printk smashes the kernel */
769 switch (crc_force) {
770 case 3:
771 ax->crcmode = CRC_MODE_SMACK;
772 printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n",
773 ax->dev->name);
774 break;
775 case 2:
776 ax->crcmode = CRC_MODE_FLEX;
777 printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n",
778 ax->dev->name);
779 break;
780 case 1:
781 ax->crcmode = CRC_MODE_NONE;
782 printk(KERN_INFO "mkiss: %s: crc mode disabled.\n",
783 ax->dev->name);
784 break;
785 case 0:
786 /* fall through */
787 default:
788 crc_force = 0;
789 printk(KERN_INFO "mkiss: %s: crc mode is auto.\n",
790 ax->dev->name);
791 ax->crcmode = CRC_MODE_SMACK_TEST;
792 }
793 ax->crcauto = (crc_force ? 0 : 1);
794
795 netif_start_queue(dev);
796
797 /* Done. We have linked the TTY line to a channel. */
798 return 0;
799
800out_free_buffers:
801 kfree(ax->rbuff);
802 kfree(ax->xbuff);
803
804out_free_netdev:
805 free_netdev(dev);
806
807out:
808 return err;
809}
810
811static void mkiss_close(struct tty_struct *tty)
812{
813 struct mkiss *ax;
814
815 write_lock_bh(&disc_data_lock);
816 ax = tty->disc_data;
817 tty->disc_data = NULL;
818 write_unlock_bh(&disc_data_lock);
819
820 if (!ax)
821 return;
822
823 /*
824 * We have now ensured that nobody can start using ap from now on, but
825 * we have to wait for all existing users to finish.
826 */
827 if (!atomic_dec_and_test(&ax->refcnt))
828 down(&ax->dead_sem);
829
830 unregister_netdev(ax->dev);
831
832 /* Free all AX25 frame buffers. */
833 kfree(ax->rbuff);
834 kfree(ax->xbuff);
835
836 ax->tty = NULL;
837}
838
839/* Perform I/O control on an active ax25 channel. */
840static int mkiss_ioctl(struct tty_struct *tty, struct file *file,
841 unsigned int cmd, unsigned long arg)
842{
843 struct mkiss *ax = mkiss_get(tty);
844 struct net_device *dev;
845 unsigned int tmp, err;
846
847 /* First make sure we're connected. */
848 if (ax == NULL)
849 return -ENXIO;
850 dev = ax->dev;
851
852 switch (cmd) {
853 case SIOCGIFNAME:
854 err = copy_to_user((void __user *) arg, ax->dev->name,
855 strlen(ax->dev->name) + 1) ? -EFAULT : 0;
856 break;
857
858 case SIOCGIFENCAP:
859 err = put_user(4, (int __user *) arg);
860 break;
861
862 case SIOCSIFENCAP:
863 if (get_user(tmp, (int __user *) arg)) {
864 err = -EFAULT;
865 break;
866 }
867
868 ax->mode = tmp;
869 dev->addr_len = AX25_ADDR_LEN;
870 dev->hard_header_len = AX25_KISS_HEADER_LEN +
871 AX25_MAX_HEADER_LEN + 3;
872 dev->type = ARPHRD_AX25;
873
874 err = 0;
875 break;
876
877 case SIOCSIFHWADDR: {
878 char addr[AX25_ADDR_LEN];
879
880 if (copy_from_user(&addr,
881 (void __user *) arg, AX25_ADDR_LEN)) {
882 err = -EFAULT;
883 break;
884 }
885
886 netif_tx_lock_bh(dev);
887 memcpy(dev->dev_addr, addr, AX25_ADDR_LEN);
888 netif_tx_unlock_bh(dev);
889
890 err = 0;
891 break;
892 }
893 default:
894 err = -ENOIOCTLCMD;
895 }
896
897 mkiss_put(ax);
898
899 return err;
900}
901
902#ifdef CONFIG_COMPAT
903static long mkiss_compat_ioctl(struct tty_struct *tty, struct file *file,
904 unsigned int cmd, unsigned long arg)
905{
906 switch (cmd) {
907 case SIOCGIFNAME:
908 case SIOCGIFENCAP:
909 case SIOCSIFENCAP:
910 case SIOCSIFHWADDR:
911 return mkiss_ioctl(tty, file, cmd,
912 (unsigned long)compat_ptr(arg));
913 }
914
915 return -ENOIOCTLCMD;
916}
917#endif
918
919/*
920 * Handle the 'receiver data ready' interrupt.
921 * This function is called by the 'tty_io' module in the kernel when
922 * a block of data has been received, which can now be decapsulated
923 * and sent on to the AX.25 layer for further processing.
924 */
925static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,
926 char *fp, int count)
927{
928 struct mkiss *ax = mkiss_get(tty);
929
930 if (!ax)
931 return;
932
933 /*
934 * Argh! mtu change time! - costs us the packet part received
935 * at the change
936 */
937 if (ax->mtu != ax->dev->mtu + 73)
938 ax_changedmtu(ax);
939
940 /* Read the characters out of the buffer */
941 while (count--) {
942 if (fp != NULL && *fp++) {
943 if (!test_and_set_bit(AXF_ERROR, &ax->flags))
944 ax->dev->stats.rx_errors++;
945 cp++;
946 continue;
947 }
948
949 kiss_unesc(ax, *cp++);
950 }
951
952 mkiss_put(ax);
953 tty_unthrottle(tty);
954}
955
956/*
957 * Called by the driver when there's room for more data. If we have
958 * more packets to send, we send them here.
959 */
960static void mkiss_write_wakeup(struct tty_struct *tty)
961{
962 struct mkiss *ax = mkiss_get(tty);
963 int actual;
964
965 if (!ax)
966 return;
967
968 if (ax->xleft <= 0) {
969 /* Now serial buffer is almost free & we can start
970 * transmission of another packet
971 */
972 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
973
974 netif_wake_queue(ax->dev);
975 goto out;
976 }
977
978 actual = tty->ops->write(tty, ax->xhead, ax->xleft);
979 ax->xleft -= actual;
980 ax->xhead += actual;
981
982out:
983 mkiss_put(ax);
984}
985
986static struct tty_ldisc_ops ax_ldisc = {
987 .owner = THIS_MODULE,
988 .magic = TTY_LDISC_MAGIC,
989 .name = "mkiss",
990 .open = mkiss_open,
991 .close = mkiss_close,
992 .ioctl = mkiss_ioctl,
993#ifdef CONFIG_COMPAT
994 .compat_ioctl = mkiss_compat_ioctl,
995#endif
996 .receive_buf = mkiss_receive_buf,
997 .write_wakeup = mkiss_write_wakeup
998};
999
1000static const char banner[] __initdata = KERN_INFO \
1001 "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n";
1002static const char msg_regfail[] __initdata = KERN_ERR \
1003 "mkiss: can't register line discipline (err = %d)\n";
1004
1005static int __init mkiss_init_driver(void)
1006{
1007 int status;
1008
1009 printk(banner);
1010
1011 status = tty_register_ldisc(N_AX25, &ax_ldisc);
1012 if (status != 0)
1013 printk(msg_regfail, status);
1014
1015 return status;
1016}
1017
1018static const char msg_unregfail[] __exitdata = KERN_ERR \
1019 "mkiss: can't unregister line discipline (err = %d)\n";
1020
1021static void __exit mkiss_exit_driver(void)
1022{
1023 int ret;
1024
1025 if ((ret = tty_unregister_ldisc(N_AX25)))
1026 printk(msg_unregfail, ret);
1027}
1028
1029MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>");
1030MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs");
1031module_param(crc_force, int, 0);
1032MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]");
1033MODULE_LICENSE("GPL");
1034MODULE_ALIAS_LDISC(N_AX25);
1035
1036module_init(mkiss_init_driver);
1037module_exit(mkiss_exit_driver);