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 | |
42 | struct 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 | |
82 | static 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 | |
117 | static 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 | |
127 | static 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 | |
143 | static 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(crc: 0, buffer: cp, len: size); |
151 | |
152 | if (crc != 0x0000) |
153 | return -1; |
154 | |
155 | return 0; |
156 | } |
157 | |
158 | /* |
159 | * Standard encapsulation |
160 | */ |
161 | |
162 | static 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 | */ |
200 | static 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. */ |
237 | static void ax_bump(struct mkiss *ax) |
238 | { |
239 | struct sk_buff *skb; |
240 | int count; |
241 | |
242 | spin_lock_bh(lock: &ax->buflock); |
243 | if (ax->rbuff[0] > 0x0f) { |
244 | if (ax->rbuff[0] & 0x80) { |
245 | if (check_crc_16(cp: ax->rbuff, size: ax->rcount) < 0) { |
246 | ax->dev->stats.rx_errors++; |
247 | spin_unlock_bh(lock: &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(cp: ax->rbuff, size: ax->rcount) < 0) { |
261 | ax->dev->stats.rx_errors++; |
262 | spin_unlock_bh(lock: &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(length: 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(lock: &ax->buflock); |
290 | return; |
291 | } |
292 | |
293 | skb_put_data(skb, data: ax->rbuff, len: count); |
294 | skb->protocol = ax25_type_trans(skb, dev: ax->dev); |
295 | netif_rx(skb); |
296 | ax->dev->stats.rx_packets++; |
297 | ax->dev->stats.rx_bytes += count; |
298 | spin_unlock_bh(lock: &ax->buflock); |
299 | } |
300 | |
301 | static 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, addr: &ax->flags); |
308 | |
309 | if (!test_and_clear_bit(AXF_ERROR, addr: &ax->flags) && (ax->rcount > 2)) |
310 | ax_bump(ax); |
311 | |
312 | clear_bit(AXF_ESCAPE, addr: &ax->flags); |
313 | ax->rcount = 0; |
314 | return; |
315 | |
316 | case ESC: |
317 | set_bit(AXF_ESCAPE, addr: &ax->flags); |
318 | return; |
319 | case ESC_ESC: |
320 | if (test_and_clear_bit(AXF_ESCAPE, addr: &ax->flags)) |
321 | s = ESC; |
322 | break; |
323 | case ESC_END: |
324 | if (test_and_clear_bit(AXF_ESCAPE, addr: &ax->flags)) |
325 | s = END; |
326 | break; |
327 | } |
328 | |
329 | spin_lock_bh(lock: &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(lock: &ax->buflock); |
334 | return; |
335 | } |
336 | |
337 | ax->dev->stats.rx_over_errors++; |
338 | set_bit(AXF_ERROR, addr: &ax->flags); |
339 | } |
340 | spin_unlock_bh(lock: &ax->buflock); |
341 | } |
342 | |
343 | static 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, addr: &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 | |
358 | static 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(size: len + 4, GFP_ATOMIC); |
375 | rbuff = kmalloc(size: 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(objp: xbuff); |
383 | kfree(objp: rbuff); |
384 | return; |
385 | } |
386 | |
387 | spin_lock_bh(lock: &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, addr: &ax->flags); |
412 | } |
413 | } |
414 | |
415 | ax->mtu = dev->mtu + 73; |
416 | ax->buffsize = len; |
417 | |
418 | spin_unlock_bh(lock: &ax->buflock); |
419 | |
420 | kfree(objp: oxbuff); |
421 | kfree(objp: orbuff); |
422 | } |
423 | |
424 | /* Encapsulate one AX.25 packet and stuff into a TTY queue. */ |
425 | static 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(lock: &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(lock: &ax->buflock); |
475 | netif_start_queue(dev); |
476 | |
477 | return; |
478 | default: |
479 | count = kiss_esc(s: p, d: 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(s: p, d: ax->xbuff, crc, len: 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(cp: p, size: len); |
500 | count = kiss_esc_crc(s: p, d: ax->xbuff, crc, len: len+2); |
501 | break; |
502 | |
503 | default: |
504 | count = kiss_esc(s: p, d: ax->xbuff, len); |
505 | } |
506 | } |
507 | spin_unlock_bh(lock: &ax->buflock); |
508 | |
509 | set_bit(TTY_DO_WRITE_WAKEUP, addr: &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(dev: 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. */ |
520 | static 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, addr: &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, icp: skb->data, len: skb->len); |
554 | kfree_skb(skb); |
555 | |
556 | return NETDEV_TX_OK; |
557 | } |
558 | |
559 | static 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! */ |
570 | static 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(size: len + 4, GFP_KERNEL)) == NULL) |
595 | goto norbuff; |
596 | |
597 | if ((ax->xbuff = kmalloc(size: 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 | |
611 | noxbuff: |
612 | kfree(objp: ax->rbuff); |
613 | |
614 | norbuff: |
615 | return -ENOMEM; |
616 | } |
617 | |
618 | |
619 | /* Close the low-level part of the AX25 channel. Easy! */ |
620 | static 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, addr: &ax->tty->flags); |
626 | |
627 | netif_stop_queue(dev); |
628 | |
629 | return 0; |
630 | } |
631 | |
632 | static 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 | |
639 | static 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, addr: (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 | */ |
665 | static DEFINE_RWLOCK(disc_data_lock); |
666 | |
667 | static 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(r: &ax->refcnt); |
675 | read_unlock(&disc_data_lock); |
676 | |
677 | return ax; |
678 | } |
679 | |
680 | static void mkiss_put(struct mkiss *ax) |
681 | { |
682 | if (refcount_dec_and_test(r: &ax->refcnt)) |
683 | complete(&ax->dead); |
684 | } |
685 | |
686 | static int crc_force = 0; /* Can be overridden with insmod */ |
687 | |
688 | static 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(r: &ax->refcnt, n: 1); |
711 | init_completion(x: &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(dev: 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 | |
762 | out_free_buffers: |
763 | kfree(objp: ax->rbuff); |
764 | kfree(objp: ax->xbuff); |
765 | |
766 | out_free_netdev: |
767 | free_netdev(dev); |
768 | |
769 | out: |
770 | return err; |
771 | } |
772 | |
773 | static 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(r: &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(dev: ax->dev); |
796 | |
797 | unregister_netdev(dev: ax->dev); |
798 | |
799 | /* Free all AX25 frame buffers after unreg. */ |
800 | kfree(objp: ax->rbuff); |
801 | kfree(objp: ax->xbuff); |
802 | |
803 | ax->tty = NULL; |
804 | |
805 | free_netdev(dev: ax->dev); |
806 | } |
807 | |
808 | /* Perform I/O control on an active ax25 channel. */ |
809 | static 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(to: (void __user *) arg, from: 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(to: &addr, |
850 | from: (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 | */ |
877 | static 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, addr: &ax->flags)) |
896 | ax->dev->stats.rx_errors++; |
897 | cp++; |
898 | continue; |
899 | } |
900 | |
901 | kiss_unesc(ax, s: *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 | */ |
912 | static 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, addr: &tty->flags); |
925 | |
926 | netif_wake_queue(dev: 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 | |
934 | out: |
935 | mkiss_put(ax); |
936 | } |
937 | |
938 | static 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 | |
949 | static const char banner[] __initconst = KERN_INFO \ |
950 | "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n" ; |
951 | static const char msg_regfail[] __initconst = KERN_ERR \ |
952 | "mkiss: can't register line discipline (err = %d)\n" ; |
953 | |
954 | static int __init mkiss_init_driver(void) |
955 | { |
956 | int status; |
957 | |
958 | printk(banner); |
959 | |
960 | status = tty_register_ldisc(new_ldisc: &ax_ldisc); |
961 | if (status != 0) |
962 | printk(msg_regfail, status); |
963 | |
964 | return status; |
965 | } |
966 | |
967 | static void __exit mkiss_exit_driver(void) |
968 | { |
969 | tty_unregister_ldisc(ldisc: &ax_ldisc); |
970 | } |
971 | |
972 | MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>" ); |
973 | MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs" ); |
974 | module_param(crc_force, int, 0); |
975 | MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]" ); |
976 | MODULE_LICENSE("GPL" ); |
977 | MODULE_ALIAS_LDISC(N_AX25); |
978 | |
979 | module_init(mkiss_init_driver); |
980 | module_exit(mkiss_exit_driver); |
981 | |