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ebpf: move CONFIG_BPF_SYSCALL-only function declarations
[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, see <http://www.gnu.org/licenses/>.
13 *
14 * Copyright (C) Hans Alblas PE1AYX <hans@esrac.ele.tue.nl>
15 * Copyright (C) 2004, 05 Ralf Baechle DL5RB <ralf@linux-mips.org>
16 * Copyright (C) 2004, 05 Thomas Osterried DL9SAU <thomas@x-berg.in-berlin.de>
17 */
18 #include <linux/module.h>
19 #include <linux/bitops.h>
20 #include <asm/uaccess.h>
21 #include <linux/crc16.h>
22 #include <linux/string.h>
23 #include <linux/mm.h>
24 #include <linux/interrupt.h>
25 #include <linux/in.h>
26 #include <linux/inet.h>
27 #include <linux/slab.h>
28 #include <linux/tty.h>
29 #include <linux/errno.h>
30 #include <linux/netdevice.h>
31 #include <linux/major.h>
32 #include <linux/init.h>
33 #include <linux/rtnetlink.h>
34 #include <linux/etherdevice.h>
35 #include <linux/skbuff.h>
36 #include <linux/if_arp.h>
37 #include <linux/jiffies.h>
38 #include <linux/compat.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: Switching 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: Switching 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, 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, 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, ax->xbuff, crc, len+2);
509 break;
510
511 default:
512 count = kiss_esc(p, 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 netdev_tx_t 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 NETDEV_TX_OK;
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", NET_NAME_UNKNOWN,
738 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
800 out_free_buffers:
801 kfree(ax->rbuff);
802 kfree(ax->xbuff);
803
804 out_free_netdev:
805 free_netdev(dev);
806
807 out:
808 return err;
809 }
810
811 static 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. */
840 static 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
903 static 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 */
925 static 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 */
960 static 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
982 out:
983 mkiss_put(ax);
984 }
985
986 static 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
1000 static const char banner[] __initconst = KERN_INFO \
1001 "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n";
1002 static const char msg_regfail[] __initconst = KERN_ERR \
1003 "mkiss: can't register line discipline (err = %d)\n";
1004
1005 static 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
1018 static const char msg_unregfail[] = KERN_ERR \
1019 "mkiss: can't unregister line discipline (err = %d)\n";
1020
1021 static 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
1029 MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>");
1030 MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs");
1031 module_param(crc_force, int, 0);
1032 MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]");
1033 MODULE_LICENSE("GPL");
1034 MODULE_ALIAS_LDISC(N_AX25);
1035
1036 module_init(mkiss_init_driver);
1037 module_exit(mkiss_exit_driver);
Linux kernel - Deliverables
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