Commit | Line | Data |
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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 | * | |
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 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> | |
6188e10d | 36 | #include <linux/semaphore.h> |
1da177e4 LT |
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 | ||
1da177e4 LT |
102 | int mtu; /* Our mtu (to spot changes!) */ |
103 | int buffsize; /* Max buffers sizes */ | |
104 | ||
105 | unsigned long flags; /* Flag values/ mode etc */ | |
106 | unsigned char mode; /* 6pack mode */ | |
107 | ||
108 | /* 6pack stuff */ | |
109 | unsigned char tx_delay; | |
110 | unsigned char persistence; | |
111 | unsigned char slottime; | |
112 | unsigned char duplex; | |
113 | unsigned char led_state; | |
114 | unsigned char status; | |
115 | unsigned char status1; | |
116 | unsigned char status2; | |
117 | unsigned char tx_enable; | |
118 | unsigned char tnc_state; | |
119 | ||
120 | struct timer_list tx_t; | |
121 | struct timer_list resync_t; | |
122 | atomic_t refcnt; | |
123 | struct semaphore dead_sem; | |
124 | spinlock_t lock; | |
125 | }; | |
126 | ||
127 | #define AX25_6PACK_HEADER_LEN 0 | |
128 | ||
1da177e4 LT |
129 | static void sixpack_decode(struct sixpack *, unsigned char[], int); |
130 | static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char); | |
131 | ||
132 | /* | |
c0438174 | 133 | * Perform the persistence/slottime algorithm for CSMA access. If the |
1da177e4 LT |
134 | * persistence check was successful, write the data to the serial driver. |
135 | * Note that in case of DAMA operation, the data is not sent here. | |
136 | */ | |
137 | ||
138 | static void sp_xmit_on_air(unsigned long channel) | |
139 | { | |
140 | struct sixpack *sp = (struct sixpack *) channel; | |
c0438174 | 141 | int actual, when = sp->slottime; |
1da177e4 LT |
142 | static unsigned char random; |
143 | ||
144 | random = random * 17 + 41; | |
145 | ||
146 | if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) { | |
147 | sp->led_state = 0x70; | |
f34d7a5b | 148 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 149 | sp->tx_enable = 1; |
f34d7a5b | 150 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); |
1da177e4 LT |
151 | sp->xleft -= actual; |
152 | sp->xhead += actual; | |
153 | sp->led_state = 0x60; | |
f34d7a5b | 154 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
155 | sp->status2 = 0; |
156 | } else | |
c0438174 | 157 | mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100); |
1da177e4 LT |
158 | } |
159 | ||
160 | /* ----> 6pack timer interrupt handler and friends. <---- */ | |
1da177e4 LT |
161 | |
162 | /* Encapsulate one AX.25 frame and stuff into a TTY queue. */ | |
163 | static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len) | |
164 | { | |
165 | unsigned char *msg, *p = icp; | |
166 | int actual, count; | |
167 | ||
168 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ | |
169 | msg = "oversized transmit packet!"; | |
170 | goto out_drop; | |
171 | } | |
172 | ||
173 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ | |
174 | msg = "oversized transmit packet!"; | |
175 | goto out_drop; | |
176 | } | |
177 | ||
178 | if (p[0] > 5) { | |
179 | msg = "invalid KISS command"; | |
180 | goto out_drop; | |
181 | } | |
182 | ||
183 | if ((p[0] != 0) && (len > 2)) { | |
184 | msg = "KISS control packet too long"; | |
185 | goto out_drop; | |
186 | } | |
187 | ||
188 | if ((p[0] == 0) && (len < 15)) { | |
189 | msg = "bad AX.25 packet to transmit"; | |
190 | goto out_drop; | |
191 | } | |
192 | ||
193 | count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay); | |
194 | set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); | |
195 | ||
196 | switch (p[0]) { | |
197 | case 1: sp->tx_delay = p[1]; | |
198 | return; | |
199 | case 2: sp->persistence = p[1]; | |
200 | return; | |
201 | case 3: sp->slottime = p[1]; | |
202 | return; | |
203 | case 4: /* ignored */ | |
204 | return; | |
205 | case 5: sp->duplex = p[1]; | |
206 | return; | |
207 | } | |
208 | ||
209 | if (p[0] != 0) | |
210 | return; | |
211 | ||
212 | /* | |
213 | * In case of fullduplex or DAMA operation, we don't take care about the | |
214 | * state of the DCD or of any timers, as the determination of the | |
215 | * correct time to send is the job of the AX.25 layer. We send | |
216 | * immediately after data has arrived. | |
217 | */ | |
218 | if (sp->duplex == 1) { | |
219 | sp->led_state = 0x70; | |
f34d7a5b | 220 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 221 | sp->tx_enable = 1; |
f34d7a5b | 222 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, count); |
1da177e4 LT |
223 | sp->xleft = count - actual; |
224 | sp->xhead = sp->xbuff + actual; | |
225 | sp->led_state = 0x60; | |
f34d7a5b | 226 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
227 | } else { |
228 | sp->xleft = count; | |
229 | sp->xhead = sp->xbuff; | |
230 | sp->status2 = count; | |
c0438174 | 231 | sp_xmit_on_air((unsigned long)sp); |
1da177e4 LT |
232 | } |
233 | ||
234 | return; | |
235 | ||
236 | out_drop: | |
de0561c4 | 237 | sp->dev->stats.tx_dropped++; |
1da177e4 LT |
238 | netif_start_queue(sp->dev); |
239 | if (net_ratelimit()) | |
240 | printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg); | |
241 | } | |
242 | ||
243 | /* Encapsulate an IP datagram and kick it into a TTY queue. */ | |
244 | ||
245 | static int sp_xmit(struct sk_buff *skb, struct net_device *dev) | |
246 | { | |
247 | struct sixpack *sp = netdev_priv(dev); | |
248 | ||
249 | spin_lock_bh(&sp->lock); | |
250 | /* We were not busy, so we are now... :-) */ | |
251 | netif_stop_queue(dev); | |
de0561c4 | 252 | dev->stats.tx_bytes += skb->len; |
1da177e4 LT |
253 | sp_encaps(sp, skb->data, skb->len); |
254 | spin_unlock_bh(&sp->lock); | |
255 | ||
256 | dev_kfree_skb(skb); | |
257 | ||
258 | return 0; | |
259 | } | |
260 | ||
261 | static int sp_open_dev(struct net_device *dev) | |
262 | { | |
263 | struct sixpack *sp = netdev_priv(dev); | |
264 | ||
265 | if (sp->tty == NULL) | |
266 | return -ENODEV; | |
267 | return 0; | |
268 | } | |
269 | ||
270 | /* Close the low-level part of the 6pack channel. */ | |
271 | static int sp_close(struct net_device *dev) | |
272 | { | |
273 | struct sixpack *sp = netdev_priv(dev); | |
274 | ||
275 | spin_lock_bh(&sp->lock); | |
276 | if (sp->tty) { | |
277 | /* TTY discipline is running. */ | |
278 | clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); | |
279 | } | |
280 | netif_stop_queue(dev); | |
281 | spin_unlock_bh(&sp->lock); | |
282 | ||
283 | return 0; | |
284 | } | |
285 | ||
286 | /* Return the frame type ID */ | |
287 | static int sp_header(struct sk_buff *skb, struct net_device *dev, | |
3b04ddde SH |
288 | unsigned short type, const void *daddr, |
289 | const void *saddr, unsigned len) | |
1da177e4 LT |
290 | { |
291 | #ifdef CONFIG_INET | |
d9a19d20 | 292 | if (type != ETH_P_AX25) |
6f74998e | 293 | return ax25_hard_header(skb, dev, type, daddr, saddr, len); |
1da177e4 LT |
294 | #endif |
295 | return 0; | |
296 | } | |
297 | ||
1da177e4 LT |
298 | static int sp_set_mac_address(struct net_device *dev, void *addr) |
299 | { | |
300 | struct sockaddr_ax25 *sa = addr; | |
301 | ||
932ff279 | 302 | netif_tx_lock_bh(dev); |
e308a5d8 | 303 | netif_addr_lock(dev); |
1da177e4 | 304 | memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); |
e308a5d8 | 305 | netif_addr_unlock(dev); |
932ff279 | 306 | netif_tx_unlock_bh(dev); |
1da177e4 LT |
307 | |
308 | return 0; | |
309 | } | |
310 | ||
311 | static int sp_rebuild_header(struct sk_buff *skb) | |
312 | { | |
313 | #ifdef CONFIG_INET | |
314 | return ax25_rebuild_header(skb); | |
315 | #else | |
316 | return 0; | |
317 | #endif | |
318 | } | |
319 | ||
3b04ddde SH |
320 | static const struct header_ops sp_header_ops = { |
321 | .create = sp_header, | |
322 | .rebuild = sp_rebuild_header, | |
323 | }; | |
324 | ||
b3672a73 SH |
325 | static const struct net_device_ops sp_netdev_ops = { |
326 | .ndo_open = sp_open_dev, | |
327 | .ndo_stop = sp_close, | |
328 | .ndo_start_xmit = sp_xmit, | |
329 | .ndo_set_mac_address = sp_set_mac_address, | |
330 | }; | |
331 | ||
1da177e4 LT |
332 | static void sp_setup(struct net_device *dev) |
333 | { | |
1da177e4 | 334 | /* Finish setting up the DEVICE info. */ |
b3672a73 | 335 | dev->netdev_ops = &sp_netdev_ops; |
1da177e4 | 336 | dev->destructor = free_netdev; |
b3672a73 | 337 | dev->mtu = SIXP_MTU; |
1da177e4 | 338 | dev->hard_header_len = AX25_MAX_HEADER_LEN; |
3b04ddde SH |
339 | dev->header_ops = &sp_header_ops; |
340 | ||
1da177e4 LT |
341 | dev->addr_len = AX25_ADDR_LEN; |
342 | dev->type = ARPHRD_AX25; | |
343 | dev->tx_queue_len = 10; | |
1da177e4 LT |
344 | |
345 | /* Only activated in AX.25 mode */ | |
15b1c0e8 RB |
346 | memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); |
347 | memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); | |
1da177e4 | 348 | |
1da177e4 LT |
349 | dev->flags = 0; |
350 | } | |
351 | ||
352 | /* Send one completely decapsulated IP datagram to the IP layer. */ | |
353 | ||
354 | /* | |
355 | * This is the routine that sends the received data to the kernel AX.25. | |
356 | * 'cmd' is the KISS command. For AX.25 data, it is zero. | |
357 | */ | |
358 | ||
359 | static void sp_bump(struct sixpack *sp, char cmd) | |
360 | { | |
361 | struct sk_buff *skb; | |
362 | int count; | |
363 | unsigned char *ptr; | |
364 | ||
365 | count = sp->rcount + 1; | |
366 | ||
de0561c4 | 367 | sp->dev->stats.rx_bytes += count; |
1da177e4 LT |
368 | |
369 | if ((skb = dev_alloc_skb(count)) == NULL) | |
370 | goto out_mem; | |
371 | ||
1da177e4 LT |
372 | ptr = skb_put(skb, count); |
373 | *ptr++ = cmd; /* KISS command */ | |
374 | ||
375 | memcpy(ptr, sp->cooked_buf + 1, count); | |
56cb5156 | 376 | skb->protocol = ax25_type_trans(skb, sp->dev); |
1da177e4 | 377 | netif_rx(skb); |
de0561c4 | 378 | sp->dev->stats.rx_packets++; |
1da177e4 LT |
379 | |
380 | return; | |
381 | ||
382 | out_mem: | |
de0561c4 | 383 | sp->dev->stats.rx_dropped++; |
1da177e4 LT |
384 | } |
385 | ||
386 | ||
387 | /* ----------------------------------------------------------------------- */ | |
388 | ||
389 | /* | |
390 | * We have a potential race on dereferencing tty->disc_data, because the tty | |
391 | * layer provides no locking at all - thus one cpu could be running | |
392 | * sixpack_receive_buf while another calls sixpack_close, which zeroes | |
393 | * tty->disc_data and frees the memory that sixpack_receive_buf is using. The | |
394 | * best way to fix this is to use a rwlock in the tty struct, but for now we | |
395 | * use a single global rwlock for all ttys in ppp line discipline. | |
396 | */ | |
397 | static DEFINE_RWLOCK(disc_data_lock); | |
398 | ||
399 | static struct sixpack *sp_get(struct tty_struct *tty) | |
400 | { | |
401 | struct sixpack *sp; | |
402 | ||
252aa9d9 | 403 | read_lock(&disc_data_lock); |
1da177e4 LT |
404 | sp = tty->disc_data; |
405 | if (sp) | |
406 | atomic_inc(&sp->refcnt); | |
252aa9d9 | 407 | read_unlock(&disc_data_lock); |
1da177e4 LT |
408 | |
409 | return sp; | |
410 | } | |
411 | ||
412 | static void sp_put(struct sixpack *sp) | |
413 | { | |
414 | if (atomic_dec_and_test(&sp->refcnt)) | |
415 | up(&sp->dead_sem); | |
416 | } | |
417 | ||
418 | /* | |
419 | * Called by the TTY driver when there's room for more data. If we have | |
420 | * more packets to send, we send them here. | |
421 | */ | |
422 | static void sixpack_write_wakeup(struct tty_struct *tty) | |
423 | { | |
424 | struct sixpack *sp = sp_get(tty); | |
425 | int actual; | |
426 | ||
427 | if (!sp) | |
428 | return; | |
429 | if (sp->xleft <= 0) { | |
430 | /* Now serial buffer is almost free & we can start | |
431 | * transmission of another packet */ | |
de0561c4 | 432 | sp->dev->stats.tx_packets++; |
1da177e4 LT |
433 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
434 | sp->tx_enable = 0; | |
435 | netif_wake_queue(sp->dev); | |
436 | goto out; | |
437 | } | |
438 | ||
439 | if (sp->tx_enable) { | |
f34d7a5b | 440 | actual = tty->ops->write(tty, sp->xhead, sp->xleft); |
1da177e4 LT |
441 | sp->xleft -= actual; |
442 | sp->xhead += actual; | |
443 | } | |
444 | ||
445 | out: | |
446 | sp_put(sp); | |
447 | } | |
448 | ||
449 | /* ----------------------------------------------------------------------- */ | |
450 | ||
1da177e4 LT |
451 | /* |
452 | * Handle the 'receiver data ready' interrupt. | |
453 | * This function is called by the 'tty_io' module in the kernel when | |
454 | * a block of 6pack data has been received, which can now be decapsulated | |
455 | * and sent on to some IP layer for further processing. | |
456 | */ | |
457 | static void sixpack_receive_buf(struct tty_struct *tty, | |
458 | const unsigned char *cp, char *fp, int count) | |
459 | { | |
460 | struct sixpack *sp; | |
461 | unsigned char buf[512]; | |
462 | int count1; | |
463 | ||
464 | if (!count) | |
465 | return; | |
466 | ||
467 | sp = sp_get(tty); | |
468 | if (!sp) | |
469 | return; | |
470 | ||
471 | memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf)); | |
472 | ||
473 | /* Read the characters out of the buffer */ | |
474 | ||
475 | count1 = count; | |
476 | while (count) { | |
477 | count--; | |
478 | if (fp && *fp++) { | |
479 | if (!test_and_set_bit(SIXPF_ERROR, &sp->flags)) | |
de0561c4 | 480 | sp->dev->stats.rx_errors++; |
1da177e4 LT |
481 | continue; |
482 | } | |
483 | } | |
484 | sixpack_decode(sp, buf, count1); | |
485 | ||
486 | sp_put(sp); | |
39c2e60f | 487 | tty_unthrottle(tty); |
1da177e4 LT |
488 | } |
489 | ||
490 | /* | |
491 | * Try to resync the TNC. Called by the resync timer defined in | |
492 | * decode_prio_command | |
493 | */ | |
494 | ||
495 | #define TNC_UNINITIALIZED 0 | |
496 | #define TNC_UNSYNC_STARTUP 1 | |
497 | #define TNC_UNSYNCED 2 | |
498 | #define TNC_IN_SYNC 3 | |
499 | ||
500 | static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
501 | { | |
502 | char *msg; | |
503 | ||
504 | switch (new_tnc_state) { | |
505 | default: /* gcc oh piece-o-crap ... */ | |
506 | case TNC_UNSYNC_STARTUP: | |
507 | msg = "Synchronizing with TNC"; | |
508 | break; | |
509 | case TNC_UNSYNCED: | |
510 | msg = "Lost synchronization with TNC\n"; | |
511 | break; | |
512 | case TNC_IN_SYNC: | |
513 | msg = "Found TNC"; | |
514 | break; | |
515 | } | |
516 | ||
517 | sp->tnc_state = new_tnc_state; | |
518 | printk(KERN_INFO "%s: %s\n", sp->dev->name, msg); | |
519 | } | |
520 | ||
521 | static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
522 | { | |
523 | int old_tnc_state = sp->tnc_state; | |
524 | ||
525 | if (old_tnc_state != new_tnc_state) | |
526 | __tnc_set_sync_state(sp, new_tnc_state); | |
527 | } | |
528 | ||
529 | static void resync_tnc(unsigned long channel) | |
530 | { | |
531 | struct sixpack *sp = (struct sixpack *) channel; | |
532 | static char resync_cmd = 0xe8; | |
533 | ||
534 | /* clear any data that might have been received */ | |
535 | ||
536 | sp->rx_count = 0; | |
537 | sp->rx_count_cooked = 0; | |
538 | ||
539 | /* reset state machine */ | |
540 | ||
541 | sp->status = 1; | |
542 | sp->status1 = 1; | |
543 | sp->status2 = 0; | |
544 | ||
545 | /* resync the TNC */ | |
546 | ||
547 | sp->led_state = 0x60; | |
f34d7a5b AC |
548 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
549 | sp->tty->ops->write(sp->tty, &resync_cmd, 1); | |
1da177e4 LT |
550 | |
551 | ||
552 | /* Start resync timer again -- the TNC might be still absent */ | |
553 | ||
554 | del_timer(&sp->resync_t); | |
555 | sp->resync_t.data = (unsigned long) sp; | |
556 | sp->resync_t.function = resync_tnc; | |
557 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
558 | add_timer(&sp->resync_t); | |
559 | } | |
560 | ||
561 | static inline int tnc_init(struct sixpack *sp) | |
562 | { | |
563 | unsigned char inbyte = 0xe8; | |
564 | ||
565 | tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP); | |
566 | ||
f34d7a5b | 567 | sp->tty->ops->write(sp->tty, &inbyte, 1); |
1da177e4 LT |
568 | |
569 | del_timer(&sp->resync_t); | |
570 | sp->resync_t.data = (unsigned long) sp; | |
571 | sp->resync_t.function = resync_tnc; | |
572 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
573 | add_timer(&sp->resync_t); | |
574 | ||
575 | return 0; | |
576 | } | |
577 | ||
578 | /* | |
579 | * Open the high-level part of the 6pack channel. | |
580 | * This function is called by the TTY module when the | |
581 | * 6pack line discipline is called for. Because we are | |
582 | * sure the tty line exists, we only have to link it to | |
583 | * a free 6pcack channel... | |
584 | */ | |
585 | static int sixpack_open(struct tty_struct *tty) | |
586 | { | |
587 | char *rbuff = NULL, *xbuff = NULL; | |
588 | struct net_device *dev; | |
589 | struct sixpack *sp; | |
590 | unsigned long len; | |
591 | int err = 0; | |
592 | ||
593 | if (!capable(CAP_NET_ADMIN)) | |
594 | return -EPERM; | |
f34d7a5b AC |
595 | if (tty->ops->write == NULL) |
596 | return -EOPNOTSUPP; | |
1da177e4 LT |
597 | |
598 | dev = alloc_netdev(sizeof(struct sixpack), "sp%d", sp_setup); | |
599 | if (!dev) { | |
600 | err = -ENOMEM; | |
601 | goto out; | |
602 | } | |
603 | ||
604 | sp = netdev_priv(dev); | |
605 | sp->dev = dev; | |
606 | ||
607 | spin_lock_init(&sp->lock); | |
608 | atomic_set(&sp->refcnt, 1); | |
609 | init_MUTEX_LOCKED(&sp->dead_sem); | |
610 | ||
611 | /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */ | |
612 | ||
613 | len = dev->mtu * 2; | |
614 | ||
615 | rbuff = kmalloc(len + 4, GFP_KERNEL); | |
616 | xbuff = kmalloc(len + 4, GFP_KERNEL); | |
617 | ||
618 | if (rbuff == NULL || xbuff == NULL) { | |
619 | err = -ENOBUFS; | |
620 | goto out_free; | |
621 | } | |
622 | ||
623 | spin_lock_bh(&sp->lock); | |
624 | ||
625 | sp->tty = tty; | |
626 | ||
627 | sp->rbuff = rbuff; | |
628 | sp->xbuff = xbuff; | |
629 | ||
630 | sp->mtu = AX25_MTU + 73; | |
631 | sp->buffsize = len; | |
632 | sp->rcount = 0; | |
633 | sp->rx_count = 0; | |
634 | sp->rx_count_cooked = 0; | |
635 | sp->xleft = 0; | |
636 | ||
637 | sp->flags = 0; /* Clear ESCAPE & ERROR flags */ | |
638 | ||
639 | sp->duplex = 0; | |
640 | sp->tx_delay = SIXP_TXDELAY; | |
641 | sp->persistence = SIXP_PERSIST; | |
642 | sp->slottime = SIXP_SLOTTIME; | |
643 | sp->led_state = 0x60; | |
644 | sp->status = 1; | |
645 | sp->status1 = 1; | |
646 | sp->status2 = 0; | |
647 | sp->tx_enable = 0; | |
648 | ||
649 | netif_start_queue(dev); | |
650 | ||
651 | init_timer(&sp->tx_t); | |
84a2ea1c RB |
652 | sp->tx_t.function = sp_xmit_on_air; |
653 | sp->tx_t.data = (unsigned long) sp; | |
654 | ||
1da177e4 LT |
655 | init_timer(&sp->resync_t); |
656 | ||
657 | spin_unlock_bh(&sp->lock); | |
658 | ||
659 | /* Done. We have linked the TTY line to a channel. */ | |
660 | tty->disc_data = sp; | |
33f0f88f | 661 | tty->receive_room = 65536; |
1da177e4 LT |
662 | |
663 | /* Now we're ready to register. */ | |
664 | if (register_netdev(dev)) | |
665 | goto out_free; | |
666 | ||
667 | tnc_init(sp); | |
668 | ||
669 | return 0; | |
670 | ||
671 | out_free: | |
672 | kfree(xbuff); | |
673 | kfree(rbuff); | |
674 | ||
675 | if (dev) | |
676 | free_netdev(dev); | |
677 | ||
678 | out: | |
679 | return err; | |
680 | } | |
681 | ||
682 | ||
683 | /* | |
684 | * Close down a 6pack channel. | |
685 | * This means flushing out any pending queues, and then restoring the | |
686 | * TTY line discipline to what it was before it got hooked to 6pack | |
687 | * (which usually is TTY again). | |
688 | */ | |
689 | static void sixpack_close(struct tty_struct *tty) | |
690 | { | |
691 | struct sixpack *sp; | |
692 | ||
252aa9d9 | 693 | write_lock(&disc_data_lock); |
1da177e4 LT |
694 | sp = tty->disc_data; |
695 | tty->disc_data = NULL; | |
252aa9d9 | 696 | write_unlock(&disc_data_lock); |
79ea13ce | 697 | if (!sp) |
1da177e4 LT |
698 | return; |
699 | ||
700 | /* | |
701 | * We have now ensured that nobody can start using ap from now on, but | |
702 | * we have to wait for all existing users to finish. | |
703 | */ | |
704 | if (!atomic_dec_and_test(&sp->refcnt)) | |
705 | down(&sp->dead_sem); | |
706 | ||
707 | unregister_netdev(sp->dev); | |
708 | ||
709 | del_timer(&sp->tx_t); | |
710 | del_timer(&sp->resync_t); | |
711 | ||
712 | /* Free all 6pack frame buffers. */ | |
713 | kfree(sp->rbuff); | |
714 | kfree(sp->xbuff); | |
715 | } | |
716 | ||
717 | /* Perform I/O control on an active 6pack channel. */ | |
718 | static int sixpack_ioctl(struct tty_struct *tty, struct file *file, | |
719 | unsigned int cmd, unsigned long arg) | |
720 | { | |
721 | struct sixpack *sp = sp_get(tty); | |
0397a264 | 722 | struct net_device *dev; |
1da177e4 LT |
723 | unsigned int tmp, err; |
724 | ||
725 | if (!sp) | |
726 | return -ENXIO; | |
0397a264 | 727 | dev = sp->dev; |
1da177e4 LT |
728 | |
729 | switch(cmd) { | |
730 | case SIOCGIFNAME: | |
731 | err = copy_to_user((void __user *) arg, dev->name, | |
732 | strlen(dev->name) + 1) ? -EFAULT : 0; | |
733 | break; | |
734 | ||
735 | case SIOCGIFENCAP: | |
736 | err = put_user(0, (int __user *) arg); | |
737 | break; | |
738 | ||
739 | case SIOCSIFENCAP: | |
740 | if (get_user(tmp, (int __user *) arg)) { | |
741 | err = -EFAULT; | |
742 | break; | |
743 | } | |
744 | ||
745 | sp->mode = tmp; | |
746 | dev->addr_len = AX25_ADDR_LEN; | |
747 | dev->hard_header_len = AX25_KISS_HEADER_LEN + | |
748 | AX25_MAX_HEADER_LEN + 3; | |
749 | dev->type = ARPHRD_AX25; | |
750 | ||
751 | err = 0; | |
752 | break; | |
753 | ||
754 | case SIOCSIFHWADDR: { | |
755 | char addr[AX25_ADDR_LEN]; | |
756 | ||
757 | if (copy_from_user(&addr, | |
758 | (void __user *) arg, AX25_ADDR_LEN)) { | |
d0127539 AC |
759 | err = -EFAULT; |
760 | break; | |
761 | } | |
1da177e4 | 762 | |
d0127539 AC |
763 | netif_tx_lock_bh(dev); |
764 | memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN); | |
765 | netif_tx_unlock_bh(dev); | |
1da177e4 | 766 | |
d0127539 AC |
767 | err = 0; |
768 | break; | |
769 | } | |
1da177e4 LT |
770 | |
771 | default: | |
d0127539 | 772 | err = tty_mode_ioctl(tty, file, cmd, arg); |
1da177e4 LT |
773 | } |
774 | ||
775 | sp_put(sp); | |
776 | ||
777 | return err; | |
778 | } | |
779 | ||
a352def2 | 780 | static struct tty_ldisc_ops sp_ldisc = { |
1da177e4 LT |
781 | .owner = THIS_MODULE, |
782 | .magic = TTY_LDISC_MAGIC, | |
783 | .name = "6pack", | |
784 | .open = sixpack_open, | |
785 | .close = sixpack_close, | |
786 | .ioctl = sixpack_ioctl, | |
787 | .receive_buf = sixpack_receive_buf, | |
1da177e4 LT |
788 | .write_wakeup = sixpack_write_wakeup, |
789 | }; | |
790 | ||
791 | /* Initialize 6pack control device -- register 6pack line discipline */ | |
792 | ||
eb33ae24 | 793 | static const char msg_banner[] __initdata = KERN_INFO \ |
1da177e4 | 794 | "AX.25: 6pack driver, " SIXPACK_VERSION "\n"; |
eb33ae24 | 795 | static const char msg_regfail[] __initdata = KERN_ERR \ |
1da177e4 LT |
796 | "6pack: can't register line discipline (err = %d)\n"; |
797 | ||
798 | static int __init sixpack_init_driver(void) | |
799 | { | |
800 | int status; | |
801 | ||
802 | printk(msg_banner); | |
803 | ||
804 | /* Register the provided line protocol discipline */ | |
805 | if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0) | |
806 | printk(msg_regfail, status); | |
807 | ||
808 | return status; | |
809 | } | |
810 | ||
811 | static const char msg_unregfail[] __exitdata = KERN_ERR \ | |
812 | "6pack: can't unregister line discipline (err = %d)\n"; | |
813 | ||
814 | static void __exit sixpack_exit_driver(void) | |
815 | { | |
816 | int ret; | |
817 | ||
64ccd715 | 818 | if ((ret = tty_unregister_ldisc(N_6PACK))) |
1da177e4 LT |
819 | printk(msg_unregfail, ret); |
820 | } | |
821 | ||
822 | /* encode an AX.25 packet into 6pack */ | |
823 | ||
824 | static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw, | |
825 | int length, unsigned char tx_delay) | |
826 | { | |
827 | int count = 0; | |
828 | unsigned char checksum = 0, buf[400]; | |
829 | int raw_count = 0; | |
830 | ||
831 | tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK; | |
832 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
833 | ||
834 | buf[0] = tx_delay; | |
835 | for (count = 1; count < length; count++) | |
836 | buf[count] = tx_buf[count]; | |
837 | ||
838 | for (count = 0; count < length; count++) | |
839 | checksum += buf[count]; | |
840 | buf[length] = (unsigned char) 0xff - checksum; | |
841 | ||
842 | for (count = 0; count <= length; count++) { | |
843 | if ((count % 3) == 0) { | |
844 | tx_buf_raw[raw_count++] = (buf[count] & 0x3f); | |
845 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30); | |
846 | } else if ((count % 3) == 1) { | |
847 | tx_buf_raw[raw_count++] |= (buf[count] & 0x0f); | |
848 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c); | |
849 | } else { | |
850 | tx_buf_raw[raw_count++] |= (buf[count] & 0x03); | |
851 | tx_buf_raw[raw_count++] = (buf[count] >> 2); | |
852 | } | |
853 | } | |
854 | if ((length % 3) != 2) | |
855 | raw_count++; | |
856 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
857 | return raw_count; | |
858 | } | |
859 | ||
860 | /* decode 4 sixpack-encoded bytes into 3 data bytes */ | |
861 | ||
862 | static void decode_data(struct sixpack *sp, unsigned char inbyte) | |
863 | { | |
864 | unsigned char *buf; | |
865 | ||
866 | if (sp->rx_count != 3) { | |
867 | sp->raw_buf[sp->rx_count++] = inbyte; | |
868 | ||
869 | return; | |
870 | } | |
871 | ||
872 | buf = sp->raw_buf; | |
873 | sp->cooked_buf[sp->rx_count_cooked++] = | |
874 | buf[0] | ((buf[1] << 2) & 0xc0); | |
875 | sp->cooked_buf[sp->rx_count_cooked++] = | |
876 | (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0); | |
877 | sp->cooked_buf[sp->rx_count_cooked++] = | |
878 | (buf[2] & 0x03) | (inbyte << 2); | |
879 | sp->rx_count = 0; | |
880 | } | |
881 | ||
882 | /* identify and execute a 6pack priority command byte */ | |
883 | ||
884 | static void decode_prio_command(struct sixpack *sp, unsigned char cmd) | |
885 | { | |
886 | unsigned char channel; | |
887 | int actual; | |
888 | ||
889 | channel = cmd & SIXP_CHN_MASK; | |
890 | if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */ | |
891 | ||
892 | /* RX and DCD flags can only be set in the same prio command, | |
893 | if the DCD flag has been set without the RX flag in the previous | |
894 | prio command. If DCD has not been set before, something in the | |
895 | transmission has gone wrong. In this case, RX and DCD are | |
896 | cleared in order to prevent the decode_data routine from | |
897 | reading further data that might be corrupt. */ | |
898 | ||
899 | if (((sp->status & SIXP_DCD_MASK) == 0) && | |
900 | ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) { | |
901 | if (sp->status != 1) | |
902 | printk(KERN_DEBUG "6pack: protocol violation\n"); | |
903 | else | |
904 | sp->status = 0; | |
95f6134e | 905 | cmd &= ~SIXP_RX_DCD_MASK; |
1da177e4 LT |
906 | } |
907 | sp->status = cmd & SIXP_PRIO_DATA_MASK; | |
908 | } else { /* output watchdog char if idle */ | |
909 | if ((sp->status2 != 0) && (sp->duplex == 1)) { | |
910 | sp->led_state = 0x70; | |
f34d7a5b | 911 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 912 | sp->tx_enable = 1; |
f34d7a5b | 913 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); |
1da177e4 LT |
914 | sp->xleft -= actual; |
915 | sp->xhead += actual; | |
916 | sp->led_state = 0x60; | |
917 | sp->status2 = 0; | |
918 | ||
919 | } | |
920 | } | |
921 | ||
922 | /* needed to trigger the TNC watchdog */ | |
f34d7a5b | 923 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
924 | |
925 | /* if the state byte has been received, the TNC is present, | |
926 | so the resync timer can be reset. */ | |
927 | ||
928 | if (sp->tnc_state == TNC_IN_SYNC) { | |
929 | del_timer(&sp->resync_t); | |
930 | sp->resync_t.data = (unsigned long) sp; | |
931 | sp->resync_t.function = resync_tnc; | |
932 | sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT; | |
933 | add_timer(&sp->resync_t); | |
934 | } | |
935 | ||
936 | sp->status1 = cmd & SIXP_PRIO_DATA_MASK; | |
937 | } | |
938 | ||
939 | /* identify and execute a standard 6pack command byte */ | |
940 | ||
941 | static void decode_std_command(struct sixpack *sp, unsigned char cmd) | |
942 | { | |
943 | unsigned char checksum = 0, rest = 0, channel; | |
944 | short i; | |
945 | ||
946 | channel = cmd & SIXP_CHN_MASK; | |
947 | switch (cmd & SIXP_CMD_MASK) { /* normal command */ | |
948 | case SIXP_SEOF: | |
949 | if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) { | |
950 | if ((sp->status & SIXP_RX_DCD_MASK) == | |
951 | SIXP_RX_DCD_MASK) { | |
952 | sp->led_state = 0x68; | |
f34d7a5b | 953 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
954 | } |
955 | } else { | |
956 | sp->led_state = 0x60; | |
957 | /* fill trailing bytes with zeroes */ | |
f34d7a5b | 958 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
959 | rest = sp->rx_count; |
960 | if (rest != 0) | |
961 | for (i = rest; i <= 3; i++) | |
962 | decode_data(sp, 0); | |
963 | if (rest == 2) | |
964 | sp->rx_count_cooked -= 2; | |
965 | else if (rest == 3) | |
966 | sp->rx_count_cooked -= 1; | |
967 | for (i = 0; i < sp->rx_count_cooked; i++) | |
968 | checksum += sp->cooked_buf[i]; | |
969 | if (checksum != SIXP_CHKSUM) { | |
970 | printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum); | |
971 | } else { | |
972 | sp->rcount = sp->rx_count_cooked-2; | |
973 | sp_bump(sp, 0); | |
974 | } | |
975 | sp->rx_count_cooked = 0; | |
976 | } | |
977 | break; | |
978 | case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n"); | |
979 | break; | |
980 | case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n"); | |
981 | break; | |
982 | case SIXP_RX_BUF_OVL: | |
983 | printk(KERN_DEBUG "6pack: RX buffer overflow\n"); | |
984 | } | |
985 | } | |
986 | ||
987 | /* decode a 6pack packet */ | |
988 | ||
989 | static void | |
990 | sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count) | |
991 | { | |
992 | unsigned char inbyte; | |
993 | int count1; | |
994 | ||
995 | for (count1 = 0; count1 < count; count1++) { | |
996 | inbyte = pre_rbuff[count1]; | |
997 | if (inbyte == SIXP_FOUND_TNC) { | |
998 | tnc_set_sync_state(sp, TNC_IN_SYNC); | |
999 | del_timer(&sp->resync_t); | |
1000 | } | |
1001 | if ((inbyte & SIXP_PRIO_CMD_MASK) != 0) | |
1002 | decode_prio_command(sp, inbyte); | |
1003 | else if ((inbyte & SIXP_STD_CMD_MASK) != 0) | |
1004 | decode_std_command(sp, inbyte); | |
1005 | else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK) | |
1006 | decode_data(sp, inbyte); | |
1007 | } | |
1008 | } | |
1009 | ||
1010 | MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>"); | |
1011 | MODULE_DESCRIPTION("6pack driver for AX.25"); | |
1012 | MODULE_LICENSE("GPL"); | |
1013 | MODULE_ALIAS_LDISC(N_6PACK); | |
1014 | ||
1015 | module_init(sixpack_init_driver); | |
1016 | module_exit(sixpack_exit_driver); |