Commit | Line | Data |
---|---|---|
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 | * | |
67332595 | 6 | * Authors: Andreas Könsgen <ajk@comnets.uni-bremen.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 | 15 | #include <linux/module.h> |
1da177e4 LT |
16 | #include <asm/uaccess.h> |
17 | #include <linux/bitops.h> | |
18 | #include <linux/string.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/interrupt.h> | |
21 | #include <linux/in.h> | |
22 | #include <linux/tty.h> | |
23 | #include <linux/errno.h> | |
24 | #include <linux/netdevice.h> | |
25 | #include <linux/timer.h> | |
5a0e3ad6 | 26 | #include <linux/slab.h> |
1da177e4 LT |
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> | |
6188e10d | 36 | #include <linux/semaphore.h> |
9646e7ce | 37 | #include <linux/compat.h> |
60063497 | 38 | #include <linux/atomic.h> |
1da177e4 LT |
39 | |
40 | #define SIXPACK_VERSION "Revision: 0.3.0" | |
41 | ||
42 | /* sixpack priority commands */ | |
43 | #define SIXP_SEOF 0x40 /* start and end of a 6pack frame */ | |
44 | #define SIXP_TX_URUN 0x48 /* transmit overrun */ | |
45 | #define SIXP_RX_ORUN 0x50 /* receive overrun */ | |
46 | #define SIXP_RX_BUF_OVL 0x58 /* receive buffer overflow */ | |
47 | ||
48 | #define SIXP_CHKSUM 0xFF /* valid checksum of a 6pack frame */ | |
49 | ||
50 | /* masks to get certain bits out of the status bytes sent by the TNC */ | |
51 | ||
52 | #define SIXP_CMD_MASK 0xC0 | |
53 | #define SIXP_CHN_MASK 0x07 | |
54 | #define SIXP_PRIO_CMD_MASK 0x80 | |
55 | #define SIXP_STD_CMD_MASK 0x40 | |
56 | #define SIXP_PRIO_DATA_MASK 0x38 | |
57 | #define SIXP_TX_MASK 0x20 | |
58 | #define SIXP_RX_MASK 0x10 | |
59 | #define SIXP_RX_DCD_MASK 0x18 | |
60 | #define SIXP_LEDS_ON 0x78 | |
61 | #define SIXP_LEDS_OFF 0x60 | |
62 | #define SIXP_CON 0x08 | |
63 | #define SIXP_STA 0x10 | |
64 | ||
65 | #define SIXP_FOUND_TNC 0xe9 | |
66 | #define SIXP_CON_ON 0x68 | |
67 | #define SIXP_DCD_MASK 0x08 | |
68 | #define SIXP_DAMA_OFF 0 | |
69 | ||
70 | /* default level 2 parameters */ | |
71 | #define SIXP_TXDELAY (HZ/4) /* in 1 s */ | |
72 | #define SIXP_PERSIST 50 /* in 256ths */ | |
73 | #define SIXP_SLOTTIME (HZ/10) /* in 1 s */ | |
74 | #define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */ | |
75 | #define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */ | |
76 | ||
77 | /* 6pack configuration. */ | |
78 | #define SIXP_NRUNIT 31 /* MAX number of 6pack channels */ | |
79 | #define SIXP_MTU 256 /* Default MTU */ | |
80 | ||
81 | enum sixpack_flags { | |
82 | SIXPF_ERROR, /* Parity, etc. error */ | |
83 | }; | |
84 | ||
85 | struct sixpack { | |
86 | /* Various fields. */ | |
87 | struct tty_struct *tty; /* ptr to TTY structure */ | |
88 | struct net_device *dev; /* easy for intr handling */ | |
89 | ||
90 | /* These are pointers to the malloc()ed frame buffers. */ | |
91 | unsigned char *rbuff; /* receiver buffer */ | |
92 | int rcount; /* received chars counter */ | |
93 | unsigned char *xbuff; /* transmitter buffer */ | |
94 | unsigned char *xhead; /* next byte to XMIT */ | |
95 | int xleft; /* bytes left in XMIT queue */ | |
96 | ||
97 | unsigned char raw_buf[4]; | |
98 | unsigned char cooked_buf[400]; | |
99 | ||
100 | unsigned int rx_count; | |
101 | unsigned int rx_count_cooked; | |
102 | ||
1da177e4 LT |
103 | int mtu; /* Our mtu (to spot changes!) */ |
104 | int buffsize; /* Max buffers sizes */ | |
105 | ||
106 | unsigned long flags; /* Flag values/ mode etc */ | |
107 | unsigned char mode; /* 6pack mode */ | |
108 | ||
109 | /* 6pack stuff */ | |
110 | unsigned char tx_delay; | |
111 | unsigned char persistence; | |
112 | unsigned char slottime; | |
113 | unsigned char duplex; | |
114 | unsigned char led_state; | |
115 | unsigned char status; | |
116 | unsigned char status1; | |
117 | unsigned char status2; | |
118 | unsigned char tx_enable; | |
119 | unsigned char tnc_state; | |
120 | ||
121 | struct timer_list tx_t; | |
122 | struct timer_list resync_t; | |
123 | atomic_t refcnt; | |
124 | struct semaphore dead_sem; | |
125 | spinlock_t lock; | |
126 | }; | |
127 | ||
128 | #define AX25_6PACK_HEADER_LEN 0 | |
129 | ||
1da177e4 LT |
130 | static void sixpack_decode(struct sixpack *, unsigned char[], int); |
131 | static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char); | |
132 | ||
133 | /* | |
c0438174 | 134 | * Perform the persistence/slottime algorithm for CSMA access. If the |
1da177e4 LT |
135 | * persistence check was successful, write the data to the serial driver. |
136 | * Note that in case of DAMA operation, the data is not sent here. | |
137 | */ | |
138 | ||
139 | static void sp_xmit_on_air(unsigned long channel) | |
140 | { | |
141 | struct sixpack *sp = (struct sixpack *) channel; | |
c0438174 | 142 | int actual, when = sp->slottime; |
1da177e4 LT |
143 | static unsigned char random; |
144 | ||
145 | random = random * 17 + 41; | |
146 | ||
147 | if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) { | |
148 | sp->led_state = 0x70; | |
f34d7a5b | 149 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 150 | sp->tx_enable = 1; |
f34d7a5b | 151 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); |
1da177e4 LT |
152 | sp->xleft -= actual; |
153 | sp->xhead += actual; | |
154 | sp->led_state = 0x60; | |
f34d7a5b | 155 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
156 | sp->status2 = 0; |
157 | } else | |
c0438174 | 158 | mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100); |
1da177e4 LT |
159 | } |
160 | ||
161 | /* ----> 6pack timer interrupt handler and friends. <---- */ | |
1da177e4 LT |
162 | |
163 | /* Encapsulate one AX.25 frame and stuff into a TTY queue. */ | |
164 | static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len) | |
165 | { | |
166 | unsigned char *msg, *p = icp; | |
167 | int actual, count; | |
168 | ||
169 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ | |
170 | msg = "oversized transmit packet!"; | |
171 | goto out_drop; | |
172 | } | |
173 | ||
174 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ | |
175 | msg = "oversized transmit packet!"; | |
176 | goto out_drop; | |
177 | } | |
178 | ||
179 | if (p[0] > 5) { | |
180 | msg = "invalid KISS command"; | |
181 | goto out_drop; | |
182 | } | |
183 | ||
184 | if ((p[0] != 0) && (len > 2)) { | |
185 | msg = "KISS control packet too long"; | |
186 | goto out_drop; | |
187 | } | |
188 | ||
189 | if ((p[0] == 0) && (len < 15)) { | |
190 | msg = "bad AX.25 packet to transmit"; | |
191 | goto out_drop; | |
192 | } | |
193 | ||
194 | count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay); | |
195 | set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); | |
196 | ||
197 | switch (p[0]) { | |
198 | case 1: sp->tx_delay = p[1]; | |
199 | return; | |
200 | case 2: sp->persistence = p[1]; | |
201 | return; | |
202 | case 3: sp->slottime = p[1]; | |
203 | return; | |
204 | case 4: /* ignored */ | |
205 | return; | |
206 | case 5: sp->duplex = p[1]; | |
207 | return; | |
208 | } | |
209 | ||
210 | if (p[0] != 0) | |
211 | return; | |
212 | ||
213 | /* | |
214 | * In case of fullduplex or DAMA operation, we don't take care about the | |
215 | * state of the DCD or of any timers, as the determination of the | |
216 | * correct time to send is the job of the AX.25 layer. We send | |
217 | * immediately after data has arrived. | |
218 | */ | |
219 | if (sp->duplex == 1) { | |
220 | sp->led_state = 0x70; | |
f34d7a5b | 221 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 222 | sp->tx_enable = 1; |
f34d7a5b | 223 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, count); |
1da177e4 LT |
224 | sp->xleft = count - actual; |
225 | sp->xhead = sp->xbuff + actual; | |
226 | sp->led_state = 0x60; | |
f34d7a5b | 227 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
228 | } else { |
229 | sp->xleft = count; | |
230 | sp->xhead = sp->xbuff; | |
231 | sp->status2 = count; | |
c0438174 | 232 | sp_xmit_on_air((unsigned long)sp); |
1da177e4 LT |
233 | } |
234 | ||
235 | return; | |
236 | ||
237 | out_drop: | |
de0561c4 | 238 | sp->dev->stats.tx_dropped++; |
1da177e4 LT |
239 | netif_start_queue(sp->dev); |
240 | if (net_ratelimit()) | |
241 | printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg); | |
242 | } | |
243 | ||
244 | /* Encapsulate an IP datagram and kick it into a TTY queue. */ | |
245 | ||
36e4d64a | 246 | static netdev_tx_t sp_xmit(struct sk_buff *skb, struct net_device *dev) |
1da177e4 LT |
247 | { |
248 | struct sixpack *sp = netdev_priv(dev); | |
249 | ||
250 | spin_lock_bh(&sp->lock); | |
251 | /* We were not busy, so we are now... :-) */ | |
252 | netif_stop_queue(dev); | |
de0561c4 | 253 | dev->stats.tx_bytes += skb->len; |
1da177e4 LT |
254 | sp_encaps(sp, skb->data, skb->len); |
255 | spin_unlock_bh(&sp->lock); | |
256 | ||
257 | dev_kfree_skb(skb); | |
258 | ||
6ed10654 | 259 | return NETDEV_TX_OK; |
1da177e4 LT |
260 | } |
261 | ||
262 | static int sp_open_dev(struct net_device *dev) | |
263 | { | |
264 | struct sixpack *sp = netdev_priv(dev); | |
265 | ||
266 | if (sp->tty == NULL) | |
267 | return -ENODEV; | |
268 | return 0; | |
269 | } | |
270 | ||
271 | /* Close the low-level part of the 6pack channel. */ | |
272 | static int sp_close(struct net_device *dev) | |
273 | { | |
274 | struct sixpack *sp = netdev_priv(dev); | |
275 | ||
276 | spin_lock_bh(&sp->lock); | |
277 | if (sp->tty) { | |
278 | /* TTY discipline is running. */ | |
279 | clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); | |
280 | } | |
281 | netif_stop_queue(dev); | |
282 | spin_unlock_bh(&sp->lock); | |
283 | ||
284 | return 0; | |
285 | } | |
286 | ||
287 | /* Return the frame type ID */ | |
288 | static int sp_header(struct sk_buff *skb, struct net_device *dev, | |
3b04ddde SH |
289 | unsigned short type, const void *daddr, |
290 | const void *saddr, unsigned len) | |
1da177e4 LT |
291 | { |
292 | #ifdef CONFIG_INET | |
d9a19d20 | 293 | if (type != ETH_P_AX25) |
6f74998e | 294 | return ax25_hard_header(skb, dev, type, daddr, saddr, len); |
1da177e4 LT |
295 | #endif |
296 | return 0; | |
297 | } | |
298 | ||
1da177e4 LT |
299 | static int sp_set_mac_address(struct net_device *dev, void *addr) |
300 | { | |
301 | struct sockaddr_ax25 *sa = addr; | |
302 | ||
932ff279 | 303 | netif_tx_lock_bh(dev); |
e308a5d8 | 304 | netif_addr_lock(dev); |
1da177e4 | 305 | memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); |
e308a5d8 | 306 | netif_addr_unlock(dev); |
932ff279 | 307 | netif_tx_unlock_bh(dev); |
1da177e4 LT |
308 | |
309 | return 0; | |
310 | } | |
311 | ||
312 | static int sp_rebuild_header(struct sk_buff *skb) | |
313 | { | |
314 | #ifdef CONFIG_INET | |
315 | return ax25_rebuild_header(skb); | |
316 | #else | |
317 | return 0; | |
318 | #endif | |
319 | } | |
320 | ||
3b04ddde SH |
321 | static const struct header_ops sp_header_ops = { |
322 | .create = sp_header, | |
323 | .rebuild = sp_rebuild_header, | |
324 | }; | |
325 | ||
b3672a73 SH |
326 | static const struct net_device_ops sp_netdev_ops = { |
327 | .ndo_open = sp_open_dev, | |
328 | .ndo_stop = sp_close, | |
329 | .ndo_start_xmit = sp_xmit, | |
330 | .ndo_set_mac_address = sp_set_mac_address, | |
331 | }; | |
332 | ||
1da177e4 LT |
333 | static void sp_setup(struct net_device *dev) |
334 | { | |
1da177e4 | 335 | /* Finish setting up the DEVICE info. */ |
b3672a73 | 336 | dev->netdev_ops = &sp_netdev_ops; |
1da177e4 | 337 | dev->destructor = free_netdev; |
b3672a73 | 338 | dev->mtu = SIXP_MTU; |
1da177e4 | 339 | dev->hard_header_len = AX25_MAX_HEADER_LEN; |
3b04ddde SH |
340 | dev->header_ops = &sp_header_ops; |
341 | ||
1da177e4 LT |
342 | dev->addr_len = AX25_ADDR_LEN; |
343 | dev->type = ARPHRD_AX25; | |
344 | dev->tx_queue_len = 10; | |
1da177e4 LT |
345 | |
346 | /* Only activated in AX.25 mode */ | |
15b1c0e8 RB |
347 | memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); |
348 | memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); | |
1da177e4 | 349 | |
1da177e4 LT |
350 | dev->flags = 0; |
351 | } | |
352 | ||
353 | /* Send one completely decapsulated IP datagram to the IP layer. */ | |
354 | ||
355 | /* | |
356 | * This is the routine that sends the received data to the kernel AX.25. | |
357 | * 'cmd' is the KISS command. For AX.25 data, it is zero. | |
358 | */ | |
359 | ||
360 | static void sp_bump(struct sixpack *sp, char cmd) | |
361 | { | |
362 | struct sk_buff *skb; | |
363 | int count; | |
364 | unsigned char *ptr; | |
365 | ||
366 | count = sp->rcount + 1; | |
367 | ||
de0561c4 | 368 | sp->dev->stats.rx_bytes += count; |
1da177e4 LT |
369 | |
370 | if ((skb = dev_alloc_skb(count)) == NULL) | |
371 | goto out_mem; | |
372 | ||
1da177e4 LT |
373 | ptr = skb_put(skb, count); |
374 | *ptr++ = cmd; /* KISS command */ | |
375 | ||
376 | memcpy(ptr, sp->cooked_buf + 1, count); | |
56cb5156 | 377 | skb->protocol = ax25_type_trans(skb, sp->dev); |
1da177e4 | 378 | netif_rx(skb); |
de0561c4 | 379 | sp->dev->stats.rx_packets++; |
1da177e4 LT |
380 | |
381 | return; | |
382 | ||
383 | out_mem: | |
de0561c4 | 384 | sp->dev->stats.rx_dropped++; |
1da177e4 LT |
385 | } |
386 | ||
387 | ||
388 | /* ----------------------------------------------------------------------- */ | |
389 | ||
390 | /* | |
391 | * We have a potential race on dereferencing tty->disc_data, because the tty | |
392 | * layer provides no locking at all - thus one cpu could be running | |
393 | * sixpack_receive_buf while another calls sixpack_close, which zeroes | |
394 | * tty->disc_data and frees the memory that sixpack_receive_buf is using. The | |
395 | * best way to fix this is to use a rwlock in the tty struct, but for now we | |
396 | * use a single global rwlock for all ttys in ppp line discipline. | |
397 | */ | |
398 | static DEFINE_RWLOCK(disc_data_lock); | |
399 | ||
400 | static struct sixpack *sp_get(struct tty_struct *tty) | |
401 | { | |
402 | struct sixpack *sp; | |
403 | ||
404 | read_lock(&disc_data_lock); | |
405 | sp = tty->disc_data; | |
406 | if (sp) | |
407 | atomic_inc(&sp->refcnt); | |
408 | read_unlock(&disc_data_lock); | |
409 | ||
410 | return sp; | |
411 | } | |
412 | ||
413 | static void sp_put(struct sixpack *sp) | |
414 | { | |
415 | if (atomic_dec_and_test(&sp->refcnt)) | |
416 | up(&sp->dead_sem); | |
417 | } | |
418 | ||
419 | /* | |
420 | * Called by the TTY driver when there's room for more data. If we have | |
421 | * more packets to send, we send them here. | |
422 | */ | |
423 | static void sixpack_write_wakeup(struct tty_struct *tty) | |
424 | { | |
425 | struct sixpack *sp = sp_get(tty); | |
426 | int actual; | |
427 | ||
428 | if (!sp) | |
429 | return; | |
430 | if (sp->xleft <= 0) { | |
431 | /* Now serial buffer is almost free & we can start | |
432 | * transmission of another packet */ | |
de0561c4 | 433 | sp->dev->stats.tx_packets++; |
1da177e4 LT |
434 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
435 | sp->tx_enable = 0; | |
436 | netif_wake_queue(sp->dev); | |
437 | goto out; | |
438 | } | |
439 | ||
440 | if (sp->tx_enable) { | |
f34d7a5b | 441 | actual = tty->ops->write(tty, sp->xhead, sp->xleft); |
1da177e4 LT |
442 | sp->xleft -= actual; |
443 | sp->xhead += actual; | |
444 | } | |
445 | ||
446 | out: | |
447 | sp_put(sp); | |
448 | } | |
449 | ||
450 | /* ----------------------------------------------------------------------- */ | |
451 | ||
1da177e4 LT |
452 | /* |
453 | * Handle the 'receiver data ready' interrupt. | |
454 | * This function is called by the 'tty_io' module in the kernel when | |
455 | * a block of 6pack data has been received, which can now be decapsulated | |
456 | * and sent on to some IP layer for further processing. | |
457 | */ | |
55db4c64 | 458 | static void sixpack_receive_buf(struct tty_struct *tty, |
1da177e4 LT |
459 | const unsigned char *cp, char *fp, int count) |
460 | { | |
461 | struct sixpack *sp; | |
462 | unsigned char buf[512]; | |
463 | int count1; | |
464 | ||
465 | if (!count) | |
55db4c64 | 466 | return; |
1da177e4 LT |
467 | |
468 | sp = sp_get(tty); | |
469 | if (!sp) | |
55db4c64 | 470 | return; |
1da177e4 LT |
471 | |
472 | memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf)); | |
473 | ||
474 | /* Read the characters out of the buffer */ | |
475 | ||
476 | count1 = count; | |
477 | while (count) { | |
478 | count--; | |
479 | if (fp && *fp++) { | |
480 | if (!test_and_set_bit(SIXPF_ERROR, &sp->flags)) | |
de0561c4 | 481 | sp->dev->stats.rx_errors++; |
1da177e4 LT |
482 | continue; |
483 | } | |
484 | } | |
485 | sixpack_decode(sp, buf, count1); | |
486 | ||
487 | sp_put(sp); | |
39c2e60f | 488 | tty_unthrottle(tty); |
1da177e4 LT |
489 | } |
490 | ||
491 | /* | |
492 | * Try to resync the TNC. Called by the resync timer defined in | |
493 | * decode_prio_command | |
494 | */ | |
495 | ||
496 | #define TNC_UNINITIALIZED 0 | |
497 | #define TNC_UNSYNC_STARTUP 1 | |
498 | #define TNC_UNSYNCED 2 | |
499 | #define TNC_IN_SYNC 3 | |
500 | ||
501 | static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
502 | { | |
503 | char *msg; | |
504 | ||
505 | switch (new_tnc_state) { | |
506 | default: /* gcc oh piece-o-crap ... */ | |
507 | case TNC_UNSYNC_STARTUP: | |
508 | msg = "Synchronizing with TNC"; | |
509 | break; | |
510 | case TNC_UNSYNCED: | |
511 | msg = "Lost synchronization with TNC\n"; | |
512 | break; | |
513 | case TNC_IN_SYNC: | |
514 | msg = "Found TNC"; | |
515 | break; | |
516 | } | |
517 | ||
518 | sp->tnc_state = new_tnc_state; | |
519 | printk(KERN_INFO "%s: %s\n", sp->dev->name, msg); | |
520 | } | |
521 | ||
522 | static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
523 | { | |
524 | int old_tnc_state = sp->tnc_state; | |
525 | ||
526 | if (old_tnc_state != new_tnc_state) | |
527 | __tnc_set_sync_state(sp, new_tnc_state); | |
528 | } | |
529 | ||
530 | static void resync_tnc(unsigned long channel) | |
531 | { | |
532 | struct sixpack *sp = (struct sixpack *) channel; | |
533 | static char resync_cmd = 0xe8; | |
534 | ||
535 | /* clear any data that might have been received */ | |
536 | ||
537 | sp->rx_count = 0; | |
538 | sp->rx_count_cooked = 0; | |
539 | ||
540 | /* reset state machine */ | |
541 | ||
542 | sp->status = 1; | |
543 | sp->status1 = 1; | |
544 | sp->status2 = 0; | |
545 | ||
546 | /* resync the TNC */ | |
547 | ||
548 | sp->led_state = 0x60; | |
f34d7a5b AC |
549 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
550 | sp->tty->ops->write(sp->tty, &resync_cmd, 1); | |
1da177e4 LT |
551 | |
552 | ||
553 | /* Start resync timer again -- the TNC might be still absent */ | |
554 | ||
555 | del_timer(&sp->resync_t); | |
556 | sp->resync_t.data = (unsigned long) sp; | |
557 | sp->resync_t.function = resync_tnc; | |
558 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
559 | add_timer(&sp->resync_t); | |
560 | } | |
561 | ||
562 | static inline int tnc_init(struct sixpack *sp) | |
563 | { | |
564 | unsigned char inbyte = 0xe8; | |
565 | ||
566 | tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP); | |
567 | ||
f34d7a5b | 568 | sp->tty->ops->write(sp->tty, &inbyte, 1); |
1da177e4 LT |
569 | |
570 | del_timer(&sp->resync_t); | |
571 | sp->resync_t.data = (unsigned long) sp; | |
572 | sp->resync_t.function = resync_tnc; | |
573 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
574 | add_timer(&sp->resync_t); | |
575 | ||
576 | return 0; | |
577 | } | |
578 | ||
579 | /* | |
580 | * Open the high-level part of the 6pack channel. | |
581 | * This function is called by the TTY module when the | |
582 | * 6pack line discipline is called for. Because we are | |
583 | * sure the tty line exists, we only have to link it to | |
584 | * a free 6pcack channel... | |
585 | */ | |
586 | static int sixpack_open(struct tty_struct *tty) | |
587 | { | |
588 | char *rbuff = NULL, *xbuff = NULL; | |
589 | struct net_device *dev; | |
590 | struct sixpack *sp; | |
591 | unsigned long len; | |
592 | int err = 0; | |
593 | ||
594 | if (!capable(CAP_NET_ADMIN)) | |
595 | return -EPERM; | |
f34d7a5b AC |
596 | if (tty->ops->write == NULL) |
597 | return -EOPNOTSUPP; | |
1da177e4 LT |
598 | |
599 | dev = alloc_netdev(sizeof(struct sixpack), "sp%d", sp_setup); | |
600 | if (!dev) { | |
601 | err = -ENOMEM; | |
602 | goto out; | |
603 | } | |
604 | ||
605 | sp = netdev_priv(dev); | |
606 | sp->dev = dev; | |
607 | ||
608 | spin_lock_init(&sp->lock); | |
609 | atomic_set(&sp->refcnt, 1); | |
89d9f10d | 610 | sema_init(&sp->dead_sem, 0); |
1da177e4 LT |
611 | |
612 | /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */ | |
613 | ||
614 | len = dev->mtu * 2; | |
615 | ||
616 | rbuff = kmalloc(len + 4, GFP_KERNEL); | |
617 | xbuff = kmalloc(len + 4, GFP_KERNEL); | |
618 | ||
619 | if (rbuff == NULL || xbuff == NULL) { | |
620 | err = -ENOBUFS; | |
621 | goto out_free; | |
622 | } | |
623 | ||
624 | spin_lock_bh(&sp->lock); | |
625 | ||
626 | sp->tty = tty; | |
627 | ||
628 | sp->rbuff = rbuff; | |
629 | sp->xbuff = xbuff; | |
630 | ||
631 | sp->mtu = AX25_MTU + 73; | |
632 | sp->buffsize = len; | |
633 | sp->rcount = 0; | |
634 | sp->rx_count = 0; | |
635 | sp->rx_count_cooked = 0; | |
636 | sp->xleft = 0; | |
637 | ||
638 | sp->flags = 0; /* Clear ESCAPE & ERROR flags */ | |
639 | ||
640 | sp->duplex = 0; | |
641 | sp->tx_delay = SIXP_TXDELAY; | |
642 | sp->persistence = SIXP_PERSIST; | |
643 | sp->slottime = SIXP_SLOTTIME; | |
644 | sp->led_state = 0x60; | |
645 | sp->status = 1; | |
646 | sp->status1 = 1; | |
647 | sp->status2 = 0; | |
648 | sp->tx_enable = 0; | |
649 | ||
650 | netif_start_queue(dev); | |
651 | ||
652 | init_timer(&sp->tx_t); | |
84a2ea1c RB |
653 | sp->tx_t.function = sp_xmit_on_air; |
654 | sp->tx_t.data = (unsigned long) sp; | |
655 | ||
1da177e4 LT |
656 | init_timer(&sp->resync_t); |
657 | ||
658 | spin_unlock_bh(&sp->lock); | |
659 | ||
660 | /* Done. We have linked the TTY line to a channel. */ | |
661 | tty->disc_data = sp; | |
33f0f88f | 662 | tty->receive_room = 65536; |
1da177e4 LT |
663 | |
664 | /* Now we're ready to register. */ | |
665 | if (register_netdev(dev)) | |
666 | goto out_free; | |
667 | ||
668 | tnc_init(sp); | |
669 | ||
670 | return 0; | |
671 | ||
672 | out_free: | |
673 | kfree(xbuff); | |
674 | kfree(rbuff); | |
675 | ||
676 | if (dev) | |
677 | free_netdev(dev); | |
678 | ||
679 | out: | |
680 | return err; | |
681 | } | |
682 | ||
683 | ||
684 | /* | |
685 | * Close down a 6pack channel. | |
686 | * This means flushing out any pending queues, and then restoring the | |
687 | * TTY line discipline to what it was before it got hooked to 6pack | |
688 | * (which usually is TTY again). | |
689 | */ | |
690 | static void sixpack_close(struct tty_struct *tty) | |
691 | { | |
692 | struct sixpack *sp; | |
693 | ||
6e4e2f81 | 694 | write_lock_bh(&disc_data_lock); |
1da177e4 LT |
695 | sp = tty->disc_data; |
696 | tty->disc_data = NULL; | |
6e4e2f81 | 697 | write_unlock_bh(&disc_data_lock); |
79ea13ce | 698 | if (!sp) |
1da177e4 LT |
699 | return; |
700 | ||
701 | /* | |
702 | * We have now ensured that nobody can start using ap from now on, but | |
703 | * we have to wait for all existing users to finish. | |
704 | */ | |
705 | if (!atomic_dec_and_test(&sp->refcnt)) | |
706 | down(&sp->dead_sem); | |
707 | ||
708 | unregister_netdev(sp->dev); | |
709 | ||
710 | del_timer(&sp->tx_t); | |
711 | del_timer(&sp->resync_t); | |
712 | ||
713 | /* Free all 6pack frame buffers. */ | |
714 | kfree(sp->rbuff); | |
715 | kfree(sp->xbuff); | |
716 | } | |
717 | ||
718 | /* Perform I/O control on an active 6pack channel. */ | |
719 | static int sixpack_ioctl(struct tty_struct *tty, struct file *file, | |
720 | unsigned int cmd, unsigned long arg) | |
721 | { | |
722 | struct sixpack *sp = sp_get(tty); | |
0397a264 | 723 | struct net_device *dev; |
1da177e4 LT |
724 | unsigned int tmp, err; |
725 | ||
726 | if (!sp) | |
727 | return -ENXIO; | |
0397a264 | 728 | dev = sp->dev; |
1da177e4 LT |
729 | |
730 | switch(cmd) { | |
731 | case SIOCGIFNAME: | |
732 | err = copy_to_user((void __user *) arg, dev->name, | |
733 | strlen(dev->name) + 1) ? -EFAULT : 0; | |
734 | break; | |
735 | ||
736 | case SIOCGIFENCAP: | |
737 | err = put_user(0, (int __user *) arg); | |
738 | break; | |
739 | ||
740 | case SIOCSIFENCAP: | |
741 | if (get_user(tmp, (int __user *) arg)) { | |
742 | err = -EFAULT; | |
743 | break; | |
744 | } | |
745 | ||
746 | sp->mode = tmp; | |
747 | dev->addr_len = AX25_ADDR_LEN; | |
748 | dev->hard_header_len = AX25_KISS_HEADER_LEN + | |
749 | AX25_MAX_HEADER_LEN + 3; | |
750 | dev->type = ARPHRD_AX25; | |
751 | ||
752 | err = 0; | |
753 | break; | |
754 | ||
755 | case SIOCSIFHWADDR: { | |
756 | char addr[AX25_ADDR_LEN]; | |
757 | ||
758 | if (copy_from_user(&addr, | |
759 | (void __user *) arg, AX25_ADDR_LEN)) { | |
d0127539 AC |
760 | err = -EFAULT; |
761 | break; | |
762 | } | |
1da177e4 | 763 | |
d0127539 AC |
764 | netif_tx_lock_bh(dev); |
765 | memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN); | |
766 | netif_tx_unlock_bh(dev); | |
1da177e4 | 767 | |
d0127539 AC |
768 | err = 0; |
769 | break; | |
770 | } | |
1da177e4 LT |
771 | |
772 | default: | |
d0127539 | 773 | err = tty_mode_ioctl(tty, file, cmd, arg); |
1da177e4 LT |
774 | } |
775 | ||
776 | sp_put(sp); | |
777 | ||
778 | return err; | |
779 | } | |
780 | ||
9646e7ce AB |
781 | #ifdef CONFIG_COMPAT |
782 | static long sixpack_compat_ioctl(struct tty_struct * tty, struct file * file, | |
783 | unsigned int cmd, unsigned long arg) | |
784 | { | |
785 | switch (cmd) { | |
786 | case SIOCGIFNAME: | |
787 | case SIOCGIFENCAP: | |
788 | case SIOCSIFENCAP: | |
789 | case SIOCSIFHWADDR: | |
790 | return sixpack_ioctl(tty, file, cmd, | |
791 | (unsigned long)compat_ptr(arg)); | |
792 | } | |
793 | ||
794 | return -ENOIOCTLCMD; | |
795 | } | |
796 | #endif | |
797 | ||
a352def2 | 798 | static struct tty_ldisc_ops sp_ldisc = { |
1da177e4 LT |
799 | .owner = THIS_MODULE, |
800 | .magic = TTY_LDISC_MAGIC, | |
801 | .name = "6pack", | |
802 | .open = sixpack_open, | |
803 | .close = sixpack_close, | |
804 | .ioctl = sixpack_ioctl, | |
9646e7ce AB |
805 | #ifdef CONFIG_COMPAT |
806 | .compat_ioctl = sixpack_compat_ioctl, | |
807 | #endif | |
1da177e4 | 808 | .receive_buf = sixpack_receive_buf, |
1da177e4 LT |
809 | .write_wakeup = sixpack_write_wakeup, |
810 | }; | |
811 | ||
812 | /* Initialize 6pack control device -- register 6pack line discipline */ | |
813 | ||
c477ebd8 | 814 | static const char msg_banner[] __initconst = KERN_INFO \ |
1da177e4 | 815 | "AX.25: 6pack driver, " SIXPACK_VERSION "\n"; |
c477ebd8 | 816 | static const char msg_regfail[] __initconst = KERN_ERR \ |
1da177e4 LT |
817 | "6pack: can't register line discipline (err = %d)\n"; |
818 | ||
819 | static int __init sixpack_init_driver(void) | |
820 | { | |
821 | int status; | |
822 | ||
823 | printk(msg_banner); | |
824 | ||
825 | /* Register the provided line protocol discipline */ | |
826 | if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0) | |
827 | printk(msg_regfail, status); | |
828 | ||
829 | return status; | |
830 | } | |
831 | ||
afa8c78b | 832 | static const char msg_unregfail[] = KERN_ERR \ |
1da177e4 LT |
833 | "6pack: can't unregister line discipline (err = %d)\n"; |
834 | ||
835 | static void __exit sixpack_exit_driver(void) | |
836 | { | |
837 | int ret; | |
838 | ||
64ccd715 | 839 | if ((ret = tty_unregister_ldisc(N_6PACK))) |
1da177e4 LT |
840 | printk(msg_unregfail, ret); |
841 | } | |
842 | ||
843 | /* encode an AX.25 packet into 6pack */ | |
844 | ||
845 | static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw, | |
846 | int length, unsigned char tx_delay) | |
847 | { | |
848 | int count = 0; | |
849 | unsigned char checksum = 0, buf[400]; | |
850 | int raw_count = 0; | |
851 | ||
852 | tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK; | |
853 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
854 | ||
855 | buf[0] = tx_delay; | |
856 | for (count = 1; count < length; count++) | |
857 | buf[count] = tx_buf[count]; | |
858 | ||
859 | for (count = 0; count < length; count++) | |
860 | checksum += buf[count]; | |
861 | buf[length] = (unsigned char) 0xff - checksum; | |
862 | ||
863 | for (count = 0; count <= length; count++) { | |
864 | if ((count % 3) == 0) { | |
865 | tx_buf_raw[raw_count++] = (buf[count] & 0x3f); | |
866 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30); | |
867 | } else if ((count % 3) == 1) { | |
868 | tx_buf_raw[raw_count++] |= (buf[count] & 0x0f); | |
869 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c); | |
870 | } else { | |
871 | tx_buf_raw[raw_count++] |= (buf[count] & 0x03); | |
872 | tx_buf_raw[raw_count++] = (buf[count] >> 2); | |
873 | } | |
874 | } | |
875 | if ((length % 3) != 2) | |
876 | raw_count++; | |
877 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
878 | return raw_count; | |
879 | } | |
880 | ||
881 | /* decode 4 sixpack-encoded bytes into 3 data bytes */ | |
882 | ||
883 | static void decode_data(struct sixpack *sp, unsigned char inbyte) | |
884 | { | |
885 | unsigned char *buf; | |
886 | ||
887 | if (sp->rx_count != 3) { | |
888 | sp->raw_buf[sp->rx_count++] = inbyte; | |
889 | ||
890 | return; | |
891 | } | |
892 | ||
893 | buf = sp->raw_buf; | |
894 | sp->cooked_buf[sp->rx_count_cooked++] = | |
895 | buf[0] | ((buf[1] << 2) & 0xc0); | |
896 | sp->cooked_buf[sp->rx_count_cooked++] = | |
897 | (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0); | |
898 | sp->cooked_buf[sp->rx_count_cooked++] = | |
899 | (buf[2] & 0x03) | (inbyte << 2); | |
900 | sp->rx_count = 0; | |
901 | } | |
902 | ||
903 | /* identify and execute a 6pack priority command byte */ | |
904 | ||
905 | static void decode_prio_command(struct sixpack *sp, unsigned char cmd) | |
906 | { | |
907 | unsigned char channel; | |
908 | int actual; | |
909 | ||
910 | channel = cmd & SIXP_CHN_MASK; | |
911 | if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */ | |
912 | ||
913 | /* RX and DCD flags can only be set in the same prio command, | |
914 | if the DCD flag has been set without the RX flag in the previous | |
915 | prio command. If DCD has not been set before, something in the | |
916 | transmission has gone wrong. In this case, RX and DCD are | |
917 | cleared in order to prevent the decode_data routine from | |
918 | reading further data that might be corrupt. */ | |
919 | ||
920 | if (((sp->status & SIXP_DCD_MASK) == 0) && | |
921 | ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) { | |
922 | if (sp->status != 1) | |
923 | printk(KERN_DEBUG "6pack: protocol violation\n"); | |
924 | else | |
925 | sp->status = 0; | |
95f6134e | 926 | cmd &= ~SIXP_RX_DCD_MASK; |
1da177e4 LT |
927 | } |
928 | sp->status = cmd & SIXP_PRIO_DATA_MASK; | |
929 | } else { /* output watchdog char if idle */ | |
930 | if ((sp->status2 != 0) && (sp->duplex == 1)) { | |
931 | sp->led_state = 0x70; | |
f34d7a5b | 932 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 933 | sp->tx_enable = 1; |
f34d7a5b | 934 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); |
1da177e4 LT |
935 | sp->xleft -= actual; |
936 | sp->xhead += actual; | |
937 | sp->led_state = 0x60; | |
938 | sp->status2 = 0; | |
939 | ||
940 | } | |
941 | } | |
942 | ||
943 | /* needed to trigger the TNC watchdog */ | |
f34d7a5b | 944 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
945 | |
946 | /* if the state byte has been received, the TNC is present, | |
947 | so the resync timer can be reset. */ | |
948 | ||
949 | if (sp->tnc_state == TNC_IN_SYNC) { | |
950 | del_timer(&sp->resync_t); | |
951 | sp->resync_t.data = (unsigned long) sp; | |
952 | sp->resync_t.function = resync_tnc; | |
953 | sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT; | |
954 | add_timer(&sp->resync_t); | |
955 | } | |
956 | ||
957 | sp->status1 = cmd & SIXP_PRIO_DATA_MASK; | |
958 | } | |
959 | ||
960 | /* identify and execute a standard 6pack command byte */ | |
961 | ||
962 | static void decode_std_command(struct sixpack *sp, unsigned char cmd) | |
963 | { | |
964 | unsigned char checksum = 0, rest = 0, channel; | |
965 | short i; | |
966 | ||
967 | channel = cmd & SIXP_CHN_MASK; | |
968 | switch (cmd & SIXP_CMD_MASK) { /* normal command */ | |
969 | case SIXP_SEOF: | |
970 | if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) { | |
971 | if ((sp->status & SIXP_RX_DCD_MASK) == | |
972 | SIXP_RX_DCD_MASK) { | |
973 | sp->led_state = 0x68; | |
f34d7a5b | 974 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
975 | } |
976 | } else { | |
977 | sp->led_state = 0x60; | |
978 | /* fill trailing bytes with zeroes */ | |
f34d7a5b | 979 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
980 | rest = sp->rx_count; |
981 | if (rest != 0) | |
982 | for (i = rest; i <= 3; i++) | |
983 | decode_data(sp, 0); | |
984 | if (rest == 2) | |
985 | sp->rx_count_cooked -= 2; | |
986 | else if (rest == 3) | |
987 | sp->rx_count_cooked -= 1; | |
988 | for (i = 0; i < sp->rx_count_cooked; i++) | |
989 | checksum += sp->cooked_buf[i]; | |
990 | if (checksum != SIXP_CHKSUM) { | |
991 | printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum); | |
992 | } else { | |
993 | sp->rcount = sp->rx_count_cooked-2; | |
994 | sp_bump(sp, 0); | |
995 | } | |
996 | sp->rx_count_cooked = 0; | |
997 | } | |
998 | break; | |
999 | case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n"); | |
1000 | break; | |
1001 | case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n"); | |
1002 | break; | |
1003 | case SIXP_RX_BUF_OVL: | |
1004 | printk(KERN_DEBUG "6pack: RX buffer overflow\n"); | |
1005 | } | |
1006 | } | |
1007 | ||
1008 | /* decode a 6pack packet */ | |
1009 | ||
1010 | static void | |
1011 | sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count) | |
1012 | { | |
1013 | unsigned char inbyte; | |
1014 | int count1; | |
1015 | ||
1016 | for (count1 = 0; count1 < count; count1++) { | |
1017 | inbyte = pre_rbuff[count1]; | |
1018 | if (inbyte == SIXP_FOUND_TNC) { | |
1019 | tnc_set_sync_state(sp, TNC_IN_SYNC); | |
1020 | del_timer(&sp->resync_t); | |
1021 | } | |
1022 | if ((inbyte & SIXP_PRIO_CMD_MASK) != 0) | |
1023 | decode_prio_command(sp, inbyte); | |
1024 | else if ((inbyte & SIXP_STD_CMD_MASK) != 0) | |
1025 | decode_std_command(sp, inbyte); | |
1026 | else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK) | |
1027 | decode_data(sp, inbyte); | |
1028 | } | |
1029 | } | |
1030 | ||
1031 | MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>"); | |
1032 | MODULE_DESCRIPTION("6pack driver for AX.25"); | |
1033 | MODULE_LICENSE("GPL"); | |
1034 | MODULE_ALIAS_LDISC(N_6PACK); | |
1035 | ||
1036 | module_init(sixpack_init_driver); | |
1037 | module_exit(sixpack_exit_driver); |