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1da177e4 LT |
1 | /* |
2 | * 6pack.c This module implements the 6pack protocol for kernel-based | |
3 | * devices like TTY. It interfaces between a raw TTY and the | |
4 | * kernel's AX.25 protocol layers. | |
5 | * | |
96de0e25 | 6 | * Authors: Andreas Könsgen <ajk@iehk.rwth-aachen.de> |
1da177e4 LT |
7 | * Ralf Baechle DL5RB <ralf@linux-mips.org> |
8 | * | |
9 | * Quite a lot of stuff "stolen" by Joerg Reuter from slip.c, written by | |
10 | * | |
11 | * Laurence Culhane, <loz@holmes.demon.co.uk> | |
12 | * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org> | |
13 | */ | |
14 | ||
1da177e4 LT |
15 | #include <linux/module.h> |
16 | #include <asm/system.h> | |
17 | #include <asm/uaccess.h> | |
18 | #include <linux/bitops.h> | |
19 | #include <linux/string.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/interrupt.h> | |
22 | #include <linux/in.h> | |
23 | #include <linux/tty.h> | |
24 | #include <linux/errno.h> | |
25 | #include <linux/netdevice.h> | |
26 | #include <linux/timer.h> | |
27 | #include <net/ax25.h> | |
28 | #include <linux/etherdevice.h> | |
29 | #include <linux/skbuff.h> | |
30 | #include <linux/rtnetlink.h> | |
31 | #include <linux/spinlock.h> | |
32 | #include <linux/if_arp.h> | |
33 | #include <linux/init.h> | |
34 | #include <linux/ip.h> | |
35 | #include <linux/tcp.h> | |
36 | #include <asm/semaphore.h> | |
37 | #include <asm/atomic.h> | |
38 | ||
39 | #define SIXPACK_VERSION "Revision: 0.3.0" | |
40 | ||
41 | /* sixpack priority commands */ | |
42 | #define SIXP_SEOF 0x40 /* start and end of a 6pack frame */ | |
43 | #define SIXP_TX_URUN 0x48 /* transmit overrun */ | |
44 | #define SIXP_RX_ORUN 0x50 /* receive overrun */ | |
45 | #define SIXP_RX_BUF_OVL 0x58 /* receive buffer overflow */ | |
46 | ||
47 | #define SIXP_CHKSUM 0xFF /* valid checksum of a 6pack frame */ | |
48 | ||
49 | /* masks to get certain bits out of the status bytes sent by the TNC */ | |
50 | ||
51 | #define SIXP_CMD_MASK 0xC0 | |
52 | #define SIXP_CHN_MASK 0x07 | |
53 | #define SIXP_PRIO_CMD_MASK 0x80 | |
54 | #define SIXP_STD_CMD_MASK 0x40 | |
55 | #define SIXP_PRIO_DATA_MASK 0x38 | |
56 | #define SIXP_TX_MASK 0x20 | |
57 | #define SIXP_RX_MASK 0x10 | |
58 | #define SIXP_RX_DCD_MASK 0x18 | |
59 | #define SIXP_LEDS_ON 0x78 | |
60 | #define SIXP_LEDS_OFF 0x60 | |
61 | #define SIXP_CON 0x08 | |
62 | #define SIXP_STA 0x10 | |
63 | ||
64 | #define SIXP_FOUND_TNC 0xe9 | |
65 | #define SIXP_CON_ON 0x68 | |
66 | #define SIXP_DCD_MASK 0x08 | |
67 | #define SIXP_DAMA_OFF 0 | |
68 | ||
69 | /* default level 2 parameters */ | |
70 | #define SIXP_TXDELAY (HZ/4) /* in 1 s */ | |
71 | #define SIXP_PERSIST 50 /* in 256ths */ | |
72 | #define SIXP_SLOTTIME (HZ/10) /* in 1 s */ | |
73 | #define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */ | |
74 | #define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */ | |
75 | ||
76 | /* 6pack configuration. */ | |
77 | #define SIXP_NRUNIT 31 /* MAX number of 6pack channels */ | |
78 | #define SIXP_MTU 256 /* Default MTU */ | |
79 | ||
80 | enum sixpack_flags { | |
81 | SIXPF_ERROR, /* Parity, etc. error */ | |
82 | }; | |
83 | ||
84 | struct sixpack { | |
85 | /* Various fields. */ | |
86 | struct tty_struct *tty; /* ptr to TTY structure */ | |
87 | struct net_device *dev; /* easy for intr handling */ | |
88 | ||
89 | /* These are pointers to the malloc()ed frame buffers. */ | |
90 | unsigned char *rbuff; /* receiver buffer */ | |
91 | int rcount; /* received chars counter */ | |
92 | unsigned char *xbuff; /* transmitter buffer */ | |
93 | unsigned char *xhead; /* next byte to XMIT */ | |
94 | int xleft; /* bytes left in XMIT queue */ | |
95 | ||
96 | unsigned char raw_buf[4]; | |
97 | unsigned char cooked_buf[400]; | |
98 | ||
99 | unsigned int rx_count; | |
100 | unsigned int rx_count_cooked; | |
101 | ||
102 | /* 6pack interface statistics. */ | |
103 | struct net_device_stats stats; | |
104 | ||
105 | int mtu; /* Our mtu (to spot changes!) */ | |
106 | int buffsize; /* Max buffers sizes */ | |
107 | ||
108 | unsigned long flags; /* Flag values/ mode etc */ | |
109 | unsigned char mode; /* 6pack mode */ | |
110 | ||
111 | /* 6pack stuff */ | |
112 | unsigned char tx_delay; | |
113 | unsigned char persistence; | |
114 | unsigned char slottime; | |
115 | unsigned char duplex; | |
116 | unsigned char led_state; | |
117 | unsigned char status; | |
118 | unsigned char status1; | |
119 | unsigned char status2; | |
120 | unsigned char tx_enable; | |
121 | unsigned char tnc_state; | |
122 | ||
123 | struct timer_list tx_t; | |
124 | struct timer_list resync_t; | |
125 | atomic_t refcnt; | |
126 | struct semaphore dead_sem; | |
127 | spinlock_t lock; | |
128 | }; | |
129 | ||
130 | #define AX25_6PACK_HEADER_LEN 0 | |
131 | ||
1da177e4 LT |
132 | static void sixpack_decode(struct sixpack *, unsigned char[], int); |
133 | static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char); | |
134 | ||
135 | /* | |
c0438174 | 136 | * Perform the persistence/slottime algorithm for CSMA access. If the |
1da177e4 LT |
137 | * persistence check was successful, write the data to the serial driver. |
138 | * Note that in case of DAMA operation, the data is not sent here. | |
139 | */ | |
140 | ||
141 | static void sp_xmit_on_air(unsigned long channel) | |
142 | { | |
143 | struct sixpack *sp = (struct sixpack *) channel; | |
c0438174 | 144 | int actual, when = sp->slottime; |
1da177e4 LT |
145 | static unsigned char random; |
146 | ||
147 | random = random * 17 + 41; | |
148 | ||
149 | if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) { | |
150 | sp->led_state = 0x70; | |
151 | sp->tty->driver->write(sp->tty, &sp->led_state, 1); | |
152 | sp->tx_enable = 1; | |
153 | actual = sp->tty->driver->write(sp->tty, sp->xbuff, sp->status2); | |
154 | sp->xleft -= actual; | |
155 | sp->xhead += actual; | |
156 | sp->led_state = 0x60; | |
157 | sp->tty->driver->write(sp->tty, &sp->led_state, 1); | |
158 | sp->status2 = 0; | |
159 | } else | |
c0438174 | 160 | mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100); |
1da177e4 LT |
161 | } |
162 | ||
163 | /* ----> 6pack timer interrupt handler and friends. <---- */ | |
1da177e4 LT |
164 | |
165 | /* Encapsulate one AX.25 frame and stuff into a TTY queue. */ | |
166 | static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len) | |
167 | { | |
168 | unsigned char *msg, *p = icp; | |
169 | int actual, count; | |
170 | ||
171 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ | |
172 | msg = "oversized transmit packet!"; | |
173 | goto out_drop; | |
174 | } | |
175 | ||
176 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ | |
177 | msg = "oversized transmit packet!"; | |
178 | goto out_drop; | |
179 | } | |
180 | ||
181 | if (p[0] > 5) { | |
182 | msg = "invalid KISS command"; | |
183 | goto out_drop; | |
184 | } | |
185 | ||
186 | if ((p[0] != 0) && (len > 2)) { | |
187 | msg = "KISS control packet too long"; | |
188 | goto out_drop; | |
189 | } | |
190 | ||
191 | if ((p[0] == 0) && (len < 15)) { | |
192 | msg = "bad AX.25 packet to transmit"; | |
193 | goto out_drop; | |
194 | } | |
195 | ||
196 | count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay); | |
197 | set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); | |
198 | ||
199 | switch (p[0]) { | |
200 | case 1: sp->tx_delay = p[1]; | |
201 | return; | |
202 | case 2: sp->persistence = p[1]; | |
203 | return; | |
204 | case 3: sp->slottime = p[1]; | |
205 | return; | |
206 | case 4: /* ignored */ | |
207 | return; | |
208 | case 5: sp->duplex = p[1]; | |
209 | return; | |
210 | } | |
211 | ||
212 | if (p[0] != 0) | |
213 | return; | |
214 | ||
215 | /* | |
216 | * In case of fullduplex or DAMA operation, we don't take care about the | |
217 | * state of the DCD or of any timers, as the determination of the | |
218 | * correct time to send is the job of the AX.25 layer. We send | |
219 | * immediately after data has arrived. | |
220 | */ | |
221 | if (sp->duplex == 1) { | |
222 | sp->led_state = 0x70; | |
223 | sp->tty->driver->write(sp->tty, &sp->led_state, 1); | |
224 | sp->tx_enable = 1; | |
225 | actual = sp->tty->driver->write(sp->tty, sp->xbuff, count); | |
226 | sp->xleft = count - actual; | |
227 | sp->xhead = sp->xbuff + actual; | |
228 | sp->led_state = 0x60; | |
229 | sp->tty->driver->write(sp->tty, &sp->led_state, 1); | |
230 | } else { | |
231 | sp->xleft = count; | |
232 | sp->xhead = sp->xbuff; | |
233 | sp->status2 = count; | |
c0438174 | 234 | sp_xmit_on_air((unsigned long)sp); |
1da177e4 LT |
235 | } |
236 | ||
237 | return; | |
238 | ||
239 | out_drop: | |
240 | sp->stats.tx_dropped++; | |
241 | netif_start_queue(sp->dev); | |
242 | if (net_ratelimit()) | |
243 | printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg); | |
244 | } | |
245 | ||
246 | /* Encapsulate an IP datagram and kick it into a TTY queue. */ | |
247 | ||
248 | static int sp_xmit(struct sk_buff *skb, struct net_device *dev) | |
249 | { | |
250 | struct sixpack *sp = netdev_priv(dev); | |
251 | ||
252 | spin_lock_bh(&sp->lock); | |
253 | /* We were not busy, so we are now... :-) */ | |
254 | netif_stop_queue(dev); | |
255 | sp->stats.tx_bytes += skb->len; | |
256 | sp_encaps(sp, skb->data, skb->len); | |
257 | spin_unlock_bh(&sp->lock); | |
258 | ||
259 | dev_kfree_skb(skb); | |
260 | ||
261 | return 0; | |
262 | } | |
263 | ||
264 | static int sp_open_dev(struct net_device *dev) | |
265 | { | |
266 | struct sixpack *sp = netdev_priv(dev); | |
267 | ||
268 | if (sp->tty == NULL) | |
269 | return -ENODEV; | |
270 | return 0; | |
271 | } | |
272 | ||
273 | /* Close the low-level part of the 6pack channel. */ | |
274 | static int sp_close(struct net_device *dev) | |
275 | { | |
276 | struct sixpack *sp = netdev_priv(dev); | |
277 | ||
278 | spin_lock_bh(&sp->lock); | |
279 | if (sp->tty) { | |
280 | /* TTY discipline is running. */ | |
281 | clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); | |
282 | } | |
283 | netif_stop_queue(dev); | |
284 | spin_unlock_bh(&sp->lock); | |
285 | ||
286 | return 0; | |
287 | } | |
288 | ||
289 | /* Return the frame type ID */ | |
290 | static int sp_header(struct sk_buff *skb, struct net_device *dev, | |
3b04ddde SH |
291 | unsigned short type, const void *daddr, |
292 | const void *saddr, unsigned len) | |
1da177e4 LT |
293 | { |
294 | #ifdef CONFIG_INET | |
d9a19d20 | 295 | if (type != ETH_P_AX25) |
6f74998e | 296 | return ax25_hard_header(skb, dev, type, daddr, saddr, len); |
1da177e4 LT |
297 | #endif |
298 | return 0; | |
299 | } | |
300 | ||
301 | static struct net_device_stats *sp_get_stats(struct net_device *dev) | |
302 | { | |
303 | struct sixpack *sp = netdev_priv(dev); | |
304 | return &sp->stats; | |
305 | } | |
306 | ||
307 | static int sp_set_mac_address(struct net_device *dev, void *addr) | |
308 | { | |
309 | struct sockaddr_ax25 *sa = addr; | |
310 | ||
932ff279 | 311 | netif_tx_lock_bh(dev); |
1da177e4 | 312 | memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); |
932ff279 | 313 | netif_tx_unlock_bh(dev); |
1da177e4 LT |
314 | |
315 | return 0; | |
316 | } | |
317 | ||
318 | static int sp_rebuild_header(struct sk_buff *skb) | |
319 | { | |
320 | #ifdef CONFIG_INET | |
321 | return ax25_rebuild_header(skb); | |
322 | #else | |
323 | return 0; | |
324 | #endif | |
325 | } | |
326 | ||
3b04ddde SH |
327 | static const struct header_ops sp_header_ops = { |
328 | .create = sp_header, | |
329 | .rebuild = sp_rebuild_header, | |
330 | }; | |
331 | ||
1da177e4 LT |
332 | static void sp_setup(struct net_device *dev) |
333 | { | |
1da177e4 LT |
334 | /* Finish setting up the DEVICE info. */ |
335 | dev->mtu = SIXP_MTU; | |
336 | dev->hard_start_xmit = sp_xmit; | |
337 | dev->open = sp_open_dev; | |
338 | dev->destructor = free_netdev; | |
339 | dev->stop = sp_close; | |
3b04ddde | 340 | |
1da177e4 LT |
341 | dev->get_stats = sp_get_stats; |
342 | dev->set_mac_address = sp_set_mac_address; | |
343 | dev->hard_header_len = AX25_MAX_HEADER_LEN; | |
3b04ddde SH |
344 | dev->header_ops = &sp_header_ops; |
345 | ||
1da177e4 LT |
346 | dev->addr_len = AX25_ADDR_LEN; |
347 | dev->type = ARPHRD_AX25; | |
348 | dev->tx_queue_len = 10; | |
1da177e4 LT |
349 | dev->tx_timeout = NULL; |
350 | ||
351 | /* Only activated in AX.25 mode */ | |
15b1c0e8 RB |
352 | memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); |
353 | memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); | |
1da177e4 | 354 | |
1da177e4 LT |
355 | dev->flags = 0; |
356 | } | |
357 | ||
358 | /* Send one completely decapsulated IP datagram to the IP layer. */ | |
359 | ||
360 | /* | |
361 | * This is the routine that sends the received data to the kernel AX.25. | |
362 | * 'cmd' is the KISS command. For AX.25 data, it is zero. | |
363 | */ | |
364 | ||
365 | static void sp_bump(struct sixpack *sp, char cmd) | |
366 | { | |
367 | struct sk_buff *skb; | |
368 | int count; | |
369 | unsigned char *ptr; | |
370 | ||
371 | count = sp->rcount + 1; | |
372 | ||
373 | sp->stats.rx_bytes += count; | |
374 | ||
375 | if ((skb = dev_alloc_skb(count)) == NULL) | |
376 | goto out_mem; | |
377 | ||
1da177e4 LT |
378 | ptr = skb_put(skb, count); |
379 | *ptr++ = cmd; /* KISS command */ | |
380 | ||
381 | memcpy(ptr, sp->cooked_buf + 1, count); | |
56cb5156 | 382 | skb->protocol = ax25_type_trans(skb, sp->dev); |
1da177e4 LT |
383 | netif_rx(skb); |
384 | sp->dev->last_rx = jiffies; | |
385 | sp->stats.rx_packets++; | |
386 | ||
387 | return; | |
388 | ||
389 | out_mem: | |
390 | sp->stats.rx_dropped++; | |
391 | } | |
392 | ||
393 | ||
394 | /* ----------------------------------------------------------------------- */ | |
395 | ||
396 | /* | |
397 | * We have a potential race on dereferencing tty->disc_data, because the tty | |
398 | * layer provides no locking at all - thus one cpu could be running | |
399 | * sixpack_receive_buf while another calls sixpack_close, which zeroes | |
400 | * tty->disc_data and frees the memory that sixpack_receive_buf is using. The | |
401 | * best way to fix this is to use a rwlock in the tty struct, but for now we | |
402 | * use a single global rwlock for all ttys in ppp line discipline. | |
403 | */ | |
404 | static DEFINE_RWLOCK(disc_data_lock); | |
405 | ||
406 | static struct sixpack *sp_get(struct tty_struct *tty) | |
407 | { | |
408 | struct sixpack *sp; | |
409 | ||
410 | read_lock(&disc_data_lock); | |
411 | sp = tty->disc_data; | |
412 | if (sp) | |
413 | atomic_inc(&sp->refcnt); | |
414 | read_unlock(&disc_data_lock); | |
415 | ||
416 | return sp; | |
417 | } | |
418 | ||
419 | static void sp_put(struct sixpack *sp) | |
420 | { | |
421 | if (atomic_dec_and_test(&sp->refcnt)) | |
422 | up(&sp->dead_sem); | |
423 | } | |
424 | ||
425 | /* | |
426 | * Called by the TTY driver when there's room for more data. If we have | |
427 | * more packets to send, we send them here. | |
428 | */ | |
429 | static void sixpack_write_wakeup(struct tty_struct *tty) | |
430 | { | |
431 | struct sixpack *sp = sp_get(tty); | |
432 | int actual; | |
433 | ||
434 | if (!sp) | |
435 | return; | |
436 | if (sp->xleft <= 0) { | |
437 | /* Now serial buffer is almost free & we can start | |
438 | * transmission of another packet */ | |
439 | sp->stats.tx_packets++; | |
440 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
441 | sp->tx_enable = 0; | |
442 | netif_wake_queue(sp->dev); | |
443 | goto out; | |
444 | } | |
445 | ||
446 | if (sp->tx_enable) { | |
447 | actual = tty->driver->write(tty, sp->xhead, sp->xleft); | |
448 | sp->xleft -= actual; | |
449 | sp->xhead += actual; | |
450 | } | |
451 | ||
452 | out: | |
453 | sp_put(sp); | |
454 | } | |
455 | ||
456 | /* ----------------------------------------------------------------------- */ | |
457 | ||
1da177e4 LT |
458 | /* |
459 | * Handle the 'receiver data ready' interrupt. | |
460 | * This function is called by the 'tty_io' module in the kernel when | |
461 | * a block of 6pack data has been received, which can now be decapsulated | |
462 | * and sent on to some IP layer for further processing. | |
463 | */ | |
464 | static void sixpack_receive_buf(struct tty_struct *tty, | |
465 | const unsigned char *cp, char *fp, int count) | |
466 | { | |
467 | struct sixpack *sp; | |
468 | unsigned char buf[512]; | |
469 | int count1; | |
470 | ||
471 | if (!count) | |
472 | return; | |
473 | ||
474 | sp = sp_get(tty); | |
475 | if (!sp) | |
476 | return; | |
477 | ||
478 | memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf)); | |
479 | ||
480 | /* Read the characters out of the buffer */ | |
481 | ||
482 | count1 = count; | |
483 | while (count) { | |
484 | count--; | |
485 | if (fp && *fp++) { | |
486 | if (!test_and_set_bit(SIXPF_ERROR, &sp->flags)) | |
487 | sp->stats.rx_errors++; | |
488 | continue; | |
489 | } | |
490 | } | |
491 | sixpack_decode(sp, buf, count1); | |
492 | ||
493 | sp_put(sp); | |
494 | if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) | |
495 | && tty->driver->unthrottle) | |
496 | tty->driver->unthrottle(tty); | |
497 | } | |
498 | ||
499 | /* | |
500 | * Try to resync the TNC. Called by the resync timer defined in | |
501 | * decode_prio_command | |
502 | */ | |
503 | ||
504 | #define TNC_UNINITIALIZED 0 | |
505 | #define TNC_UNSYNC_STARTUP 1 | |
506 | #define TNC_UNSYNCED 2 | |
507 | #define TNC_IN_SYNC 3 | |
508 | ||
509 | static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
510 | { | |
511 | char *msg; | |
512 | ||
513 | switch (new_tnc_state) { | |
514 | default: /* gcc oh piece-o-crap ... */ | |
515 | case TNC_UNSYNC_STARTUP: | |
516 | msg = "Synchronizing with TNC"; | |
517 | break; | |
518 | case TNC_UNSYNCED: | |
519 | msg = "Lost synchronization with TNC\n"; | |
520 | break; | |
521 | case TNC_IN_SYNC: | |
522 | msg = "Found TNC"; | |
523 | break; | |
524 | } | |
525 | ||
526 | sp->tnc_state = new_tnc_state; | |
527 | printk(KERN_INFO "%s: %s\n", sp->dev->name, msg); | |
528 | } | |
529 | ||
530 | static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
531 | { | |
532 | int old_tnc_state = sp->tnc_state; | |
533 | ||
534 | if (old_tnc_state != new_tnc_state) | |
535 | __tnc_set_sync_state(sp, new_tnc_state); | |
536 | } | |
537 | ||
538 | static void resync_tnc(unsigned long channel) | |
539 | { | |
540 | struct sixpack *sp = (struct sixpack *) channel; | |
541 | static char resync_cmd = 0xe8; | |
542 | ||
543 | /* clear any data that might have been received */ | |
544 | ||
545 | sp->rx_count = 0; | |
546 | sp->rx_count_cooked = 0; | |
547 | ||
548 | /* reset state machine */ | |
549 | ||
550 | sp->status = 1; | |
551 | sp->status1 = 1; | |
552 | sp->status2 = 0; | |
553 | ||
554 | /* resync the TNC */ | |
555 | ||
556 | sp->led_state = 0x60; | |
557 | sp->tty->driver->write(sp->tty, &sp->led_state, 1); | |
558 | sp->tty->driver->write(sp->tty, &resync_cmd, 1); | |
559 | ||
560 | ||
561 | /* Start resync timer again -- the TNC might be still absent */ | |
562 | ||
563 | del_timer(&sp->resync_t); | |
564 | sp->resync_t.data = (unsigned long) sp; | |
565 | sp->resync_t.function = resync_tnc; | |
566 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
567 | add_timer(&sp->resync_t); | |
568 | } | |
569 | ||
570 | static inline int tnc_init(struct sixpack *sp) | |
571 | { | |
572 | unsigned char inbyte = 0xe8; | |
573 | ||
574 | tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP); | |
575 | ||
576 | sp->tty->driver->write(sp->tty, &inbyte, 1); | |
577 | ||
578 | del_timer(&sp->resync_t); | |
579 | sp->resync_t.data = (unsigned long) sp; | |
580 | sp->resync_t.function = resync_tnc; | |
581 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
582 | add_timer(&sp->resync_t); | |
583 | ||
584 | return 0; | |
585 | } | |
586 | ||
587 | /* | |
588 | * Open the high-level part of the 6pack channel. | |
589 | * This function is called by the TTY module when the | |
590 | * 6pack line discipline is called for. Because we are | |
591 | * sure the tty line exists, we only have to link it to | |
592 | * a free 6pcack channel... | |
593 | */ | |
594 | static int sixpack_open(struct tty_struct *tty) | |
595 | { | |
596 | char *rbuff = NULL, *xbuff = NULL; | |
597 | struct net_device *dev; | |
598 | struct sixpack *sp; | |
599 | unsigned long len; | |
600 | int err = 0; | |
601 | ||
602 | if (!capable(CAP_NET_ADMIN)) | |
603 | return -EPERM; | |
604 | ||
605 | dev = alloc_netdev(sizeof(struct sixpack), "sp%d", sp_setup); | |
606 | if (!dev) { | |
607 | err = -ENOMEM; | |
608 | goto out; | |
609 | } | |
610 | ||
611 | sp = netdev_priv(dev); | |
612 | sp->dev = dev; | |
613 | ||
614 | spin_lock_init(&sp->lock); | |
615 | atomic_set(&sp->refcnt, 1); | |
616 | init_MUTEX_LOCKED(&sp->dead_sem); | |
617 | ||
618 | /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */ | |
619 | ||
620 | len = dev->mtu * 2; | |
621 | ||
622 | rbuff = kmalloc(len + 4, GFP_KERNEL); | |
623 | xbuff = kmalloc(len + 4, GFP_KERNEL); | |
624 | ||
625 | if (rbuff == NULL || xbuff == NULL) { | |
626 | err = -ENOBUFS; | |
627 | goto out_free; | |
628 | } | |
629 | ||
630 | spin_lock_bh(&sp->lock); | |
631 | ||
632 | sp->tty = tty; | |
633 | ||
634 | sp->rbuff = rbuff; | |
635 | sp->xbuff = xbuff; | |
636 | ||
637 | sp->mtu = AX25_MTU + 73; | |
638 | sp->buffsize = len; | |
639 | sp->rcount = 0; | |
640 | sp->rx_count = 0; | |
641 | sp->rx_count_cooked = 0; | |
642 | sp->xleft = 0; | |
643 | ||
644 | sp->flags = 0; /* Clear ESCAPE & ERROR flags */ | |
645 | ||
646 | sp->duplex = 0; | |
647 | sp->tx_delay = SIXP_TXDELAY; | |
648 | sp->persistence = SIXP_PERSIST; | |
649 | sp->slottime = SIXP_SLOTTIME; | |
650 | sp->led_state = 0x60; | |
651 | sp->status = 1; | |
652 | sp->status1 = 1; | |
653 | sp->status2 = 0; | |
654 | sp->tx_enable = 0; | |
655 | ||
656 | netif_start_queue(dev); | |
657 | ||
658 | init_timer(&sp->tx_t); | |
84a2ea1c RB |
659 | sp->tx_t.function = sp_xmit_on_air; |
660 | sp->tx_t.data = (unsigned long) sp; | |
661 | ||
1da177e4 LT |
662 | init_timer(&sp->resync_t); |
663 | ||
664 | spin_unlock_bh(&sp->lock); | |
665 | ||
666 | /* Done. We have linked the TTY line to a channel. */ | |
667 | tty->disc_data = sp; | |
33f0f88f | 668 | tty->receive_room = 65536; |
1da177e4 LT |
669 | |
670 | /* Now we're ready to register. */ | |
671 | if (register_netdev(dev)) | |
672 | goto out_free; | |
673 | ||
674 | tnc_init(sp); | |
675 | ||
676 | return 0; | |
677 | ||
678 | out_free: | |
679 | kfree(xbuff); | |
680 | kfree(rbuff); | |
681 | ||
682 | if (dev) | |
683 | free_netdev(dev); | |
684 | ||
685 | out: | |
686 | return err; | |
687 | } | |
688 | ||
689 | ||
690 | /* | |
691 | * Close down a 6pack channel. | |
692 | * This means flushing out any pending queues, and then restoring the | |
693 | * TTY line discipline to what it was before it got hooked to 6pack | |
694 | * (which usually is TTY again). | |
695 | */ | |
696 | static void sixpack_close(struct tty_struct *tty) | |
697 | { | |
698 | struct sixpack *sp; | |
699 | ||
700 | write_lock(&disc_data_lock); | |
701 | sp = tty->disc_data; | |
702 | tty->disc_data = NULL; | |
703 | write_unlock(&disc_data_lock); | |
79ea13ce | 704 | if (!sp) |
1da177e4 LT |
705 | return; |
706 | ||
707 | /* | |
708 | * We have now ensured that nobody can start using ap from now on, but | |
709 | * we have to wait for all existing users to finish. | |
710 | */ | |
711 | if (!atomic_dec_and_test(&sp->refcnt)) | |
712 | down(&sp->dead_sem); | |
713 | ||
714 | unregister_netdev(sp->dev); | |
715 | ||
716 | del_timer(&sp->tx_t); | |
717 | del_timer(&sp->resync_t); | |
718 | ||
719 | /* Free all 6pack frame buffers. */ | |
720 | kfree(sp->rbuff); | |
721 | kfree(sp->xbuff); | |
722 | } | |
723 | ||
724 | /* Perform I/O control on an active 6pack channel. */ | |
725 | static int sixpack_ioctl(struct tty_struct *tty, struct file *file, | |
726 | unsigned int cmd, unsigned long arg) | |
727 | { | |
728 | struct sixpack *sp = sp_get(tty); | |
729 | struct net_device *dev = sp->dev; | |
730 | unsigned int tmp, err; | |
731 | ||
732 | if (!sp) | |
733 | return -ENXIO; | |
734 | ||
735 | switch(cmd) { | |
736 | case SIOCGIFNAME: | |
737 | err = copy_to_user((void __user *) arg, dev->name, | |
738 | strlen(dev->name) + 1) ? -EFAULT : 0; | |
739 | break; | |
740 | ||
741 | case SIOCGIFENCAP: | |
742 | err = put_user(0, (int __user *) arg); | |
743 | break; | |
744 | ||
745 | case SIOCSIFENCAP: | |
746 | if (get_user(tmp, (int __user *) arg)) { | |
747 | err = -EFAULT; | |
748 | break; | |
749 | } | |
750 | ||
751 | sp->mode = tmp; | |
752 | dev->addr_len = AX25_ADDR_LEN; | |
753 | dev->hard_header_len = AX25_KISS_HEADER_LEN + | |
754 | AX25_MAX_HEADER_LEN + 3; | |
755 | dev->type = ARPHRD_AX25; | |
756 | ||
757 | err = 0; | |
758 | break; | |
759 | ||
760 | case SIOCSIFHWADDR: { | |
761 | char addr[AX25_ADDR_LEN]; | |
762 | ||
763 | if (copy_from_user(&addr, | |
764 | (void __user *) arg, AX25_ADDR_LEN)) { | |
d0127539 AC |
765 | err = -EFAULT; |
766 | break; | |
767 | } | |
1da177e4 | 768 | |
d0127539 AC |
769 | netif_tx_lock_bh(dev); |
770 | memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN); | |
771 | netif_tx_unlock_bh(dev); | |
1da177e4 | 772 | |
d0127539 AC |
773 | err = 0; |
774 | break; | |
775 | } | |
1da177e4 LT |
776 | |
777 | default: | |
d0127539 | 778 | err = tty_mode_ioctl(tty, file, cmd, arg); |
1da177e4 LT |
779 | } |
780 | ||
781 | sp_put(sp); | |
782 | ||
783 | return err; | |
784 | } | |
785 | ||
786 | static struct tty_ldisc sp_ldisc = { | |
787 | .owner = THIS_MODULE, | |
788 | .magic = TTY_LDISC_MAGIC, | |
789 | .name = "6pack", | |
790 | .open = sixpack_open, | |
791 | .close = sixpack_close, | |
792 | .ioctl = sixpack_ioctl, | |
793 | .receive_buf = sixpack_receive_buf, | |
1da177e4 LT |
794 | .write_wakeup = sixpack_write_wakeup, |
795 | }; | |
796 | ||
797 | /* Initialize 6pack control device -- register 6pack line discipline */ | |
798 | ||
799 | static char msg_banner[] __initdata = KERN_INFO \ | |
800 | "AX.25: 6pack driver, " SIXPACK_VERSION "\n"; | |
801 | static char msg_regfail[] __initdata = KERN_ERR \ | |
802 | "6pack: can't register line discipline (err = %d)\n"; | |
803 | ||
804 | static int __init sixpack_init_driver(void) | |
805 | { | |
806 | int status; | |
807 | ||
808 | printk(msg_banner); | |
809 | ||
810 | /* Register the provided line protocol discipline */ | |
811 | if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0) | |
812 | printk(msg_regfail, status); | |
813 | ||
814 | return status; | |
815 | } | |
816 | ||
817 | static const char msg_unregfail[] __exitdata = KERN_ERR \ | |
818 | "6pack: can't unregister line discipline (err = %d)\n"; | |
819 | ||
820 | static void __exit sixpack_exit_driver(void) | |
821 | { | |
822 | int ret; | |
823 | ||
64ccd715 | 824 | if ((ret = tty_unregister_ldisc(N_6PACK))) |
1da177e4 LT |
825 | printk(msg_unregfail, ret); |
826 | } | |
827 | ||
828 | /* encode an AX.25 packet into 6pack */ | |
829 | ||
830 | static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw, | |
831 | int length, unsigned char tx_delay) | |
832 | { | |
833 | int count = 0; | |
834 | unsigned char checksum = 0, buf[400]; | |
835 | int raw_count = 0; | |
836 | ||
837 | tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK; | |
838 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
839 | ||
840 | buf[0] = tx_delay; | |
841 | for (count = 1; count < length; count++) | |
842 | buf[count] = tx_buf[count]; | |
843 | ||
844 | for (count = 0; count < length; count++) | |
845 | checksum += buf[count]; | |
846 | buf[length] = (unsigned char) 0xff - checksum; | |
847 | ||
848 | for (count = 0; count <= length; count++) { | |
849 | if ((count % 3) == 0) { | |
850 | tx_buf_raw[raw_count++] = (buf[count] & 0x3f); | |
851 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30); | |
852 | } else if ((count % 3) == 1) { | |
853 | tx_buf_raw[raw_count++] |= (buf[count] & 0x0f); | |
854 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c); | |
855 | } else { | |
856 | tx_buf_raw[raw_count++] |= (buf[count] & 0x03); | |
857 | tx_buf_raw[raw_count++] = (buf[count] >> 2); | |
858 | } | |
859 | } | |
860 | if ((length % 3) != 2) | |
861 | raw_count++; | |
862 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
863 | return raw_count; | |
864 | } | |
865 | ||
866 | /* decode 4 sixpack-encoded bytes into 3 data bytes */ | |
867 | ||
868 | static void decode_data(struct sixpack *sp, unsigned char inbyte) | |
869 | { | |
870 | unsigned char *buf; | |
871 | ||
872 | if (sp->rx_count != 3) { | |
873 | sp->raw_buf[sp->rx_count++] = inbyte; | |
874 | ||
875 | return; | |
876 | } | |
877 | ||
878 | buf = sp->raw_buf; | |
879 | sp->cooked_buf[sp->rx_count_cooked++] = | |
880 | buf[0] | ((buf[1] << 2) & 0xc0); | |
881 | sp->cooked_buf[sp->rx_count_cooked++] = | |
882 | (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0); | |
883 | sp->cooked_buf[sp->rx_count_cooked++] = | |
884 | (buf[2] & 0x03) | (inbyte << 2); | |
885 | sp->rx_count = 0; | |
886 | } | |
887 | ||
888 | /* identify and execute a 6pack priority command byte */ | |
889 | ||
890 | static void decode_prio_command(struct sixpack *sp, unsigned char cmd) | |
891 | { | |
892 | unsigned char channel; | |
893 | int actual; | |
894 | ||
895 | channel = cmd & SIXP_CHN_MASK; | |
896 | if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */ | |
897 | ||
898 | /* RX and DCD flags can only be set in the same prio command, | |
899 | if the DCD flag has been set without the RX flag in the previous | |
900 | prio command. If DCD has not been set before, something in the | |
901 | transmission has gone wrong. In this case, RX and DCD are | |
902 | cleared in order to prevent the decode_data routine from | |
903 | reading further data that might be corrupt. */ | |
904 | ||
905 | if (((sp->status & SIXP_DCD_MASK) == 0) && | |
906 | ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) { | |
907 | if (sp->status != 1) | |
908 | printk(KERN_DEBUG "6pack: protocol violation\n"); | |
909 | else | |
910 | sp->status = 0; | |
95f6134e | 911 | cmd &= ~SIXP_RX_DCD_MASK; |
1da177e4 LT |
912 | } |
913 | sp->status = cmd & SIXP_PRIO_DATA_MASK; | |
914 | } else { /* output watchdog char if idle */ | |
915 | if ((sp->status2 != 0) && (sp->duplex == 1)) { | |
916 | sp->led_state = 0x70; | |
917 | sp->tty->driver->write(sp->tty, &sp->led_state, 1); | |
918 | sp->tx_enable = 1; | |
919 | actual = sp->tty->driver->write(sp->tty, sp->xbuff, sp->status2); | |
920 | sp->xleft -= actual; | |
921 | sp->xhead += actual; | |
922 | sp->led_state = 0x60; | |
923 | sp->status2 = 0; | |
924 | ||
925 | } | |
926 | } | |
927 | ||
928 | /* needed to trigger the TNC watchdog */ | |
929 | sp->tty->driver->write(sp->tty, &sp->led_state, 1); | |
930 | ||
931 | /* if the state byte has been received, the TNC is present, | |
932 | so the resync timer can be reset. */ | |
933 | ||
934 | if (sp->tnc_state == TNC_IN_SYNC) { | |
935 | del_timer(&sp->resync_t); | |
936 | sp->resync_t.data = (unsigned long) sp; | |
937 | sp->resync_t.function = resync_tnc; | |
938 | sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT; | |
939 | add_timer(&sp->resync_t); | |
940 | } | |
941 | ||
942 | sp->status1 = cmd & SIXP_PRIO_DATA_MASK; | |
943 | } | |
944 | ||
945 | /* identify and execute a standard 6pack command byte */ | |
946 | ||
947 | static void decode_std_command(struct sixpack *sp, unsigned char cmd) | |
948 | { | |
949 | unsigned char checksum = 0, rest = 0, channel; | |
950 | short i; | |
951 | ||
952 | channel = cmd & SIXP_CHN_MASK; | |
953 | switch (cmd & SIXP_CMD_MASK) { /* normal command */ | |
954 | case SIXP_SEOF: | |
955 | if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) { | |
956 | if ((sp->status & SIXP_RX_DCD_MASK) == | |
957 | SIXP_RX_DCD_MASK) { | |
958 | sp->led_state = 0x68; | |
959 | sp->tty->driver->write(sp->tty, &sp->led_state, 1); | |
960 | } | |
961 | } else { | |
962 | sp->led_state = 0x60; | |
963 | /* fill trailing bytes with zeroes */ | |
964 | sp->tty->driver->write(sp->tty, &sp->led_state, 1); | |
965 | rest = sp->rx_count; | |
966 | if (rest != 0) | |
967 | for (i = rest; i <= 3; i++) | |
968 | decode_data(sp, 0); | |
969 | if (rest == 2) | |
970 | sp->rx_count_cooked -= 2; | |
971 | else if (rest == 3) | |
972 | sp->rx_count_cooked -= 1; | |
973 | for (i = 0; i < sp->rx_count_cooked; i++) | |
974 | checksum += sp->cooked_buf[i]; | |
975 | if (checksum != SIXP_CHKSUM) { | |
976 | printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum); | |
977 | } else { | |
978 | sp->rcount = sp->rx_count_cooked-2; | |
979 | sp_bump(sp, 0); | |
980 | } | |
981 | sp->rx_count_cooked = 0; | |
982 | } | |
983 | break; | |
984 | case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n"); | |
985 | break; | |
986 | case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n"); | |
987 | break; | |
988 | case SIXP_RX_BUF_OVL: | |
989 | printk(KERN_DEBUG "6pack: RX buffer overflow\n"); | |
990 | } | |
991 | } | |
992 | ||
993 | /* decode a 6pack packet */ | |
994 | ||
995 | static void | |
996 | sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count) | |
997 | { | |
998 | unsigned char inbyte; | |
999 | int count1; | |
1000 | ||
1001 | for (count1 = 0; count1 < count; count1++) { | |
1002 | inbyte = pre_rbuff[count1]; | |
1003 | if (inbyte == SIXP_FOUND_TNC) { | |
1004 | tnc_set_sync_state(sp, TNC_IN_SYNC); | |
1005 | del_timer(&sp->resync_t); | |
1006 | } | |
1007 | if ((inbyte & SIXP_PRIO_CMD_MASK) != 0) | |
1008 | decode_prio_command(sp, inbyte); | |
1009 | else if ((inbyte & SIXP_STD_CMD_MASK) != 0) | |
1010 | decode_std_command(sp, inbyte); | |
1011 | else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK) | |
1012 | decode_data(sp, inbyte); | |
1013 | } | |
1014 | } | |
1015 | ||
1016 | MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>"); | |
1017 | MODULE_DESCRIPTION("6pack driver for AX.25"); | |
1018 | MODULE_LICENSE("GPL"); | |
1019 | MODULE_ALIAS_LDISC(N_6PACK); | |
1020 | ||
1021 | module_init(sixpack_init_driver); | |
1022 | module_exit(sixpack_exit_driver); |