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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> | |
5a0e3ad6 | 27 | #include <linux/slab.h> |
1da177e4 LT |
28 | #include <net/ax25.h> |
29 | #include <linux/etherdevice.h> | |
30 | #include <linux/skbuff.h> | |
31 | #include <linux/rtnetlink.h> | |
32 | #include <linux/spinlock.h> | |
33 | #include <linux/if_arp.h> | |
34 | #include <linux/init.h> | |
35 | #include <linux/ip.h> | |
36 | #include <linux/tcp.h> | |
6188e10d | 37 | #include <linux/semaphore.h> |
9646e7ce | 38 | #include <linux/compat.h> |
1da177e4 LT |
39 | #include <asm/atomic.h> |
40 | ||
41 | #define SIXPACK_VERSION "Revision: 0.3.0" | |
42 | ||
43 | /* sixpack priority commands */ | |
44 | #define SIXP_SEOF 0x40 /* start and end of a 6pack frame */ | |
45 | #define SIXP_TX_URUN 0x48 /* transmit overrun */ | |
46 | #define SIXP_RX_ORUN 0x50 /* receive overrun */ | |
47 | #define SIXP_RX_BUF_OVL 0x58 /* receive buffer overflow */ | |
48 | ||
49 | #define SIXP_CHKSUM 0xFF /* valid checksum of a 6pack frame */ | |
50 | ||
51 | /* masks to get certain bits out of the status bytes sent by the TNC */ | |
52 | ||
53 | #define SIXP_CMD_MASK 0xC0 | |
54 | #define SIXP_CHN_MASK 0x07 | |
55 | #define SIXP_PRIO_CMD_MASK 0x80 | |
56 | #define SIXP_STD_CMD_MASK 0x40 | |
57 | #define SIXP_PRIO_DATA_MASK 0x38 | |
58 | #define SIXP_TX_MASK 0x20 | |
59 | #define SIXP_RX_MASK 0x10 | |
60 | #define SIXP_RX_DCD_MASK 0x18 | |
61 | #define SIXP_LEDS_ON 0x78 | |
62 | #define SIXP_LEDS_OFF 0x60 | |
63 | #define SIXP_CON 0x08 | |
64 | #define SIXP_STA 0x10 | |
65 | ||
66 | #define SIXP_FOUND_TNC 0xe9 | |
67 | #define SIXP_CON_ON 0x68 | |
68 | #define SIXP_DCD_MASK 0x08 | |
69 | #define SIXP_DAMA_OFF 0 | |
70 | ||
71 | /* default level 2 parameters */ | |
72 | #define SIXP_TXDELAY (HZ/4) /* in 1 s */ | |
73 | #define SIXP_PERSIST 50 /* in 256ths */ | |
74 | #define SIXP_SLOTTIME (HZ/10) /* in 1 s */ | |
75 | #define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */ | |
76 | #define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */ | |
77 | ||
78 | /* 6pack configuration. */ | |
79 | #define SIXP_NRUNIT 31 /* MAX number of 6pack channels */ | |
80 | #define SIXP_MTU 256 /* Default MTU */ | |
81 | ||
82 | enum sixpack_flags { | |
83 | SIXPF_ERROR, /* Parity, etc. error */ | |
84 | }; | |
85 | ||
86 | struct sixpack { | |
87 | /* Various fields. */ | |
88 | struct tty_struct *tty; /* ptr to TTY structure */ | |
89 | struct net_device *dev; /* easy for intr handling */ | |
90 | ||
91 | /* These are pointers to the malloc()ed frame buffers. */ | |
92 | unsigned char *rbuff; /* receiver buffer */ | |
93 | int rcount; /* received chars counter */ | |
94 | unsigned char *xbuff; /* transmitter buffer */ | |
95 | unsigned char *xhead; /* next byte to XMIT */ | |
96 | int xleft; /* bytes left in XMIT queue */ | |
97 | ||
98 | unsigned char raw_buf[4]; | |
99 | unsigned char cooked_buf[400]; | |
100 | ||
101 | unsigned int rx_count; | |
102 | unsigned int rx_count_cooked; | |
103 | ||
1da177e4 LT |
104 | int mtu; /* Our mtu (to spot changes!) */ |
105 | int buffsize; /* Max buffers sizes */ | |
106 | ||
107 | unsigned long flags; /* Flag values/ mode etc */ | |
108 | unsigned char mode; /* 6pack mode */ | |
109 | ||
110 | /* 6pack stuff */ | |
111 | unsigned char tx_delay; | |
112 | unsigned char persistence; | |
113 | unsigned char slottime; | |
114 | unsigned char duplex; | |
115 | unsigned char led_state; | |
116 | unsigned char status; | |
117 | unsigned char status1; | |
118 | unsigned char status2; | |
119 | unsigned char tx_enable; | |
120 | unsigned char tnc_state; | |
121 | ||
122 | struct timer_list tx_t; | |
123 | struct timer_list resync_t; | |
124 | atomic_t refcnt; | |
125 | struct semaphore dead_sem; | |
126 | spinlock_t lock; | |
127 | }; | |
128 | ||
129 | #define AX25_6PACK_HEADER_LEN 0 | |
130 | ||
1da177e4 LT |
131 | static void sixpack_decode(struct sixpack *, unsigned char[], int); |
132 | static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char); | |
133 | ||
134 | /* | |
c0438174 | 135 | * Perform the persistence/slottime algorithm for CSMA access. If the |
1da177e4 LT |
136 | * persistence check was successful, write the data to the serial driver. |
137 | * Note that in case of DAMA operation, the data is not sent here. | |
138 | */ | |
139 | ||
140 | static void sp_xmit_on_air(unsigned long channel) | |
141 | { | |
142 | struct sixpack *sp = (struct sixpack *) channel; | |
c0438174 | 143 | int actual, when = sp->slottime; |
1da177e4 LT |
144 | static unsigned char random; |
145 | ||
146 | random = random * 17 + 41; | |
147 | ||
148 | if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) { | |
149 | sp->led_state = 0x70; | |
f34d7a5b | 150 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 151 | sp->tx_enable = 1; |
f34d7a5b | 152 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); |
1da177e4 LT |
153 | sp->xleft -= actual; |
154 | sp->xhead += actual; | |
155 | sp->led_state = 0x60; | |
f34d7a5b | 156 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
157 | sp->status2 = 0; |
158 | } else | |
c0438174 | 159 | mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100); |
1da177e4 LT |
160 | } |
161 | ||
162 | /* ----> 6pack timer interrupt handler and friends. <---- */ | |
1da177e4 LT |
163 | |
164 | /* Encapsulate one AX.25 frame and stuff into a TTY queue. */ | |
165 | static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len) | |
166 | { | |
167 | unsigned char *msg, *p = icp; | |
168 | int actual, count; | |
169 | ||
170 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ | |
171 | msg = "oversized transmit packet!"; | |
172 | goto out_drop; | |
173 | } | |
174 | ||
175 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ | |
176 | msg = "oversized transmit packet!"; | |
177 | goto out_drop; | |
178 | } | |
179 | ||
180 | if (p[0] > 5) { | |
181 | msg = "invalid KISS command"; | |
182 | goto out_drop; | |
183 | } | |
184 | ||
185 | if ((p[0] != 0) && (len > 2)) { | |
186 | msg = "KISS control packet too long"; | |
187 | goto out_drop; | |
188 | } | |
189 | ||
190 | if ((p[0] == 0) && (len < 15)) { | |
191 | msg = "bad AX.25 packet to transmit"; | |
192 | goto out_drop; | |
193 | } | |
194 | ||
195 | count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay); | |
196 | set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); | |
197 | ||
198 | switch (p[0]) { | |
199 | case 1: sp->tx_delay = p[1]; | |
200 | return; | |
201 | case 2: sp->persistence = p[1]; | |
202 | return; | |
203 | case 3: sp->slottime = p[1]; | |
204 | return; | |
205 | case 4: /* ignored */ | |
206 | return; | |
207 | case 5: sp->duplex = p[1]; | |
208 | return; | |
209 | } | |
210 | ||
211 | if (p[0] != 0) | |
212 | return; | |
213 | ||
214 | /* | |
215 | * In case of fullduplex or DAMA operation, we don't take care about the | |
216 | * state of the DCD or of any timers, as the determination of the | |
217 | * correct time to send is the job of the AX.25 layer. We send | |
218 | * immediately after data has arrived. | |
219 | */ | |
220 | if (sp->duplex == 1) { | |
221 | sp->led_state = 0x70; | |
f34d7a5b | 222 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 223 | sp->tx_enable = 1; |
f34d7a5b | 224 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, count); |
1da177e4 LT |
225 | sp->xleft = count - actual; |
226 | sp->xhead = sp->xbuff + actual; | |
227 | sp->led_state = 0x60; | |
f34d7a5b | 228 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
229 | } else { |
230 | sp->xleft = count; | |
231 | sp->xhead = sp->xbuff; | |
232 | sp->status2 = count; | |
c0438174 | 233 | sp_xmit_on_air((unsigned long)sp); |
1da177e4 LT |
234 | } |
235 | ||
236 | return; | |
237 | ||
238 | out_drop: | |
de0561c4 | 239 | sp->dev->stats.tx_dropped++; |
1da177e4 LT |
240 | netif_start_queue(sp->dev); |
241 | if (net_ratelimit()) | |
242 | printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg); | |
243 | } | |
244 | ||
245 | /* Encapsulate an IP datagram and kick it into a TTY queue. */ | |
246 | ||
36e4d64a | 247 | static netdev_tx_t sp_xmit(struct sk_buff *skb, struct net_device *dev) |
1da177e4 LT |
248 | { |
249 | struct sixpack *sp = netdev_priv(dev); | |
250 | ||
251 | spin_lock_bh(&sp->lock); | |
252 | /* We were not busy, so we are now... :-) */ | |
253 | netif_stop_queue(dev); | |
de0561c4 | 254 | dev->stats.tx_bytes += skb->len; |
1da177e4 LT |
255 | sp_encaps(sp, skb->data, skb->len); |
256 | spin_unlock_bh(&sp->lock); | |
257 | ||
258 | dev_kfree_skb(skb); | |
259 | ||
6ed10654 | 260 | return NETDEV_TX_OK; |
1da177e4 LT |
261 | } |
262 | ||
263 | static int sp_open_dev(struct net_device *dev) | |
264 | { | |
265 | struct sixpack *sp = netdev_priv(dev); | |
266 | ||
267 | if (sp->tty == NULL) | |
268 | return -ENODEV; | |
269 | return 0; | |
270 | } | |
271 | ||
272 | /* Close the low-level part of the 6pack channel. */ | |
273 | static int sp_close(struct net_device *dev) | |
274 | { | |
275 | struct sixpack *sp = netdev_priv(dev); | |
276 | ||
277 | spin_lock_bh(&sp->lock); | |
278 | if (sp->tty) { | |
279 | /* TTY discipline is running. */ | |
280 | clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); | |
281 | } | |
282 | netif_stop_queue(dev); | |
283 | spin_unlock_bh(&sp->lock); | |
284 | ||
285 | return 0; | |
286 | } | |
287 | ||
288 | /* Return the frame type ID */ | |
289 | static int sp_header(struct sk_buff *skb, struct net_device *dev, | |
3b04ddde SH |
290 | unsigned short type, const void *daddr, |
291 | const void *saddr, unsigned len) | |
1da177e4 LT |
292 | { |
293 | #ifdef CONFIG_INET | |
d9a19d20 | 294 | if (type != ETH_P_AX25) |
6f74998e | 295 | return ax25_hard_header(skb, dev, type, daddr, saddr, len); |
1da177e4 LT |
296 | #endif |
297 | return 0; | |
298 | } | |
299 | ||
1da177e4 LT |
300 | static int sp_set_mac_address(struct net_device *dev, void *addr) |
301 | { | |
302 | struct sockaddr_ax25 *sa = addr; | |
303 | ||
932ff279 | 304 | netif_tx_lock_bh(dev); |
e308a5d8 | 305 | netif_addr_lock(dev); |
1da177e4 | 306 | memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); |
e308a5d8 | 307 | netif_addr_unlock(dev); |
932ff279 | 308 | netif_tx_unlock_bh(dev); |
1da177e4 LT |
309 | |
310 | return 0; | |
311 | } | |
312 | ||
313 | static int sp_rebuild_header(struct sk_buff *skb) | |
314 | { | |
315 | #ifdef CONFIG_INET | |
316 | return ax25_rebuild_header(skb); | |
317 | #else | |
318 | return 0; | |
319 | #endif | |
320 | } | |
321 | ||
3b04ddde SH |
322 | static const struct header_ops sp_header_ops = { |
323 | .create = sp_header, | |
324 | .rebuild = sp_rebuild_header, | |
325 | }; | |
326 | ||
b3672a73 SH |
327 | static const struct net_device_ops sp_netdev_ops = { |
328 | .ndo_open = sp_open_dev, | |
329 | .ndo_stop = sp_close, | |
330 | .ndo_start_xmit = sp_xmit, | |
331 | .ndo_set_mac_address = sp_set_mac_address, | |
332 | }; | |
333 | ||
1da177e4 LT |
334 | static void sp_setup(struct net_device *dev) |
335 | { | |
1da177e4 | 336 | /* Finish setting up the DEVICE info. */ |
b3672a73 | 337 | dev->netdev_ops = &sp_netdev_ops; |
1da177e4 | 338 | dev->destructor = free_netdev; |
b3672a73 | 339 | dev->mtu = SIXP_MTU; |
1da177e4 | 340 | dev->hard_header_len = AX25_MAX_HEADER_LEN; |
3b04ddde SH |
341 | dev->header_ops = &sp_header_ops; |
342 | ||
1da177e4 LT |
343 | dev->addr_len = AX25_ADDR_LEN; |
344 | dev->type = ARPHRD_AX25; | |
345 | dev->tx_queue_len = 10; | |
1da177e4 LT |
346 | |
347 | /* Only activated in AX.25 mode */ | |
15b1c0e8 RB |
348 | memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); |
349 | memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); | |
1da177e4 | 350 | |
1da177e4 LT |
351 | dev->flags = 0; |
352 | } | |
353 | ||
354 | /* Send one completely decapsulated IP datagram to the IP layer. */ | |
355 | ||
356 | /* | |
357 | * This is the routine that sends the received data to the kernel AX.25. | |
358 | * 'cmd' is the KISS command. For AX.25 data, it is zero. | |
359 | */ | |
360 | ||
361 | static void sp_bump(struct sixpack *sp, char cmd) | |
362 | { | |
363 | struct sk_buff *skb; | |
364 | int count; | |
365 | unsigned char *ptr; | |
366 | ||
367 | count = sp->rcount + 1; | |
368 | ||
de0561c4 | 369 | sp->dev->stats.rx_bytes += count; |
1da177e4 LT |
370 | |
371 | if ((skb = dev_alloc_skb(count)) == NULL) | |
372 | goto out_mem; | |
373 | ||
1da177e4 LT |
374 | ptr = skb_put(skb, count); |
375 | *ptr++ = cmd; /* KISS command */ | |
376 | ||
377 | memcpy(ptr, sp->cooked_buf + 1, count); | |
56cb5156 | 378 | skb->protocol = ax25_type_trans(skb, sp->dev); |
1da177e4 | 379 | netif_rx(skb); |
de0561c4 | 380 | sp->dev->stats.rx_packets++; |
1da177e4 LT |
381 | |
382 | return; | |
383 | ||
384 | out_mem: | |
de0561c4 | 385 | sp->dev->stats.rx_dropped++; |
1da177e4 LT |
386 | } |
387 | ||
388 | ||
389 | /* ----------------------------------------------------------------------- */ | |
390 | ||
391 | /* | |
392 | * We have a potential race on dereferencing tty->disc_data, because the tty | |
393 | * layer provides no locking at all - thus one cpu could be running | |
394 | * sixpack_receive_buf while another calls sixpack_close, which zeroes | |
395 | * tty->disc_data and frees the memory that sixpack_receive_buf is using. The | |
396 | * best way to fix this is to use a rwlock in the tty struct, but for now we | |
397 | * use a single global rwlock for all ttys in ppp line discipline. | |
398 | */ | |
399 | static DEFINE_RWLOCK(disc_data_lock); | |
400 | ||
401 | static struct sixpack *sp_get(struct tty_struct *tty) | |
402 | { | |
403 | struct sixpack *sp; | |
404 | ||
405 | read_lock(&disc_data_lock); | |
406 | sp = tty->disc_data; | |
407 | if (sp) | |
408 | atomic_inc(&sp->refcnt); | |
409 | read_unlock(&disc_data_lock); | |
410 | ||
411 | return sp; | |
412 | } | |
413 | ||
414 | static void sp_put(struct sixpack *sp) | |
415 | { | |
416 | if (atomic_dec_and_test(&sp->refcnt)) | |
417 | up(&sp->dead_sem); | |
418 | } | |
419 | ||
420 | /* | |
421 | * Called by the TTY driver when there's room for more data. If we have | |
422 | * more packets to send, we send them here. | |
423 | */ | |
424 | static void sixpack_write_wakeup(struct tty_struct *tty) | |
425 | { | |
426 | struct sixpack *sp = sp_get(tty); | |
427 | int actual; | |
428 | ||
429 | if (!sp) | |
430 | return; | |
431 | if (sp->xleft <= 0) { | |
432 | /* Now serial buffer is almost free & we can start | |
433 | * transmission of another packet */ | |
de0561c4 | 434 | sp->dev->stats.tx_packets++; |
1da177e4 LT |
435 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
436 | sp->tx_enable = 0; | |
437 | netif_wake_queue(sp->dev); | |
438 | goto out; | |
439 | } | |
440 | ||
441 | if (sp->tx_enable) { | |
f34d7a5b | 442 | actual = tty->ops->write(tty, sp->xhead, sp->xleft); |
1da177e4 LT |
443 | sp->xleft -= actual; |
444 | sp->xhead += actual; | |
445 | } | |
446 | ||
447 | out: | |
448 | sp_put(sp); | |
449 | } | |
450 | ||
451 | /* ----------------------------------------------------------------------- */ | |
452 | ||
1da177e4 LT |
453 | /* |
454 | * Handle the 'receiver data ready' interrupt. | |
455 | * This function is called by the 'tty_io' module in the kernel when | |
456 | * a block of 6pack data has been received, which can now be decapsulated | |
457 | * and sent on to some IP layer for further processing. | |
458 | */ | |
55db4c64 | 459 | static void sixpack_receive_buf(struct tty_struct *tty, |
1da177e4 LT |
460 | const unsigned char *cp, char *fp, int count) |
461 | { | |
462 | struct sixpack *sp; | |
463 | unsigned char buf[512]; | |
464 | int count1; | |
465 | ||
466 | if (!count) | |
55db4c64 | 467 | return; |
1da177e4 LT |
468 | |
469 | sp = sp_get(tty); | |
470 | if (!sp) | |
55db4c64 | 471 | return; |
1da177e4 LT |
472 | |
473 | memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf)); | |
474 | ||
475 | /* Read the characters out of the buffer */ | |
476 | ||
477 | count1 = count; | |
478 | while (count) { | |
479 | count--; | |
480 | if (fp && *fp++) { | |
481 | if (!test_and_set_bit(SIXPF_ERROR, &sp->flags)) | |
de0561c4 | 482 | sp->dev->stats.rx_errors++; |
1da177e4 LT |
483 | continue; |
484 | } | |
485 | } | |
486 | sixpack_decode(sp, buf, count1); | |
487 | ||
488 | sp_put(sp); | |
39c2e60f | 489 | tty_unthrottle(tty); |
1da177e4 LT |
490 | } |
491 | ||
492 | /* | |
493 | * Try to resync the TNC. Called by the resync timer defined in | |
494 | * decode_prio_command | |
495 | */ | |
496 | ||
497 | #define TNC_UNINITIALIZED 0 | |
498 | #define TNC_UNSYNC_STARTUP 1 | |
499 | #define TNC_UNSYNCED 2 | |
500 | #define TNC_IN_SYNC 3 | |
501 | ||
502 | static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
503 | { | |
504 | char *msg; | |
505 | ||
506 | switch (new_tnc_state) { | |
507 | default: /* gcc oh piece-o-crap ... */ | |
508 | case TNC_UNSYNC_STARTUP: | |
509 | msg = "Synchronizing with TNC"; | |
510 | break; | |
511 | case TNC_UNSYNCED: | |
512 | msg = "Lost synchronization with TNC\n"; | |
513 | break; | |
514 | case TNC_IN_SYNC: | |
515 | msg = "Found TNC"; | |
516 | break; | |
517 | } | |
518 | ||
519 | sp->tnc_state = new_tnc_state; | |
520 | printk(KERN_INFO "%s: %s\n", sp->dev->name, msg); | |
521 | } | |
522 | ||
523 | static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
524 | { | |
525 | int old_tnc_state = sp->tnc_state; | |
526 | ||
527 | if (old_tnc_state != new_tnc_state) | |
528 | __tnc_set_sync_state(sp, new_tnc_state); | |
529 | } | |
530 | ||
531 | static void resync_tnc(unsigned long channel) | |
532 | { | |
533 | struct sixpack *sp = (struct sixpack *) channel; | |
534 | static char resync_cmd = 0xe8; | |
535 | ||
536 | /* clear any data that might have been received */ | |
537 | ||
538 | sp->rx_count = 0; | |
539 | sp->rx_count_cooked = 0; | |
540 | ||
541 | /* reset state machine */ | |
542 | ||
543 | sp->status = 1; | |
544 | sp->status1 = 1; | |
545 | sp->status2 = 0; | |
546 | ||
547 | /* resync the TNC */ | |
548 | ||
549 | sp->led_state = 0x60; | |
f34d7a5b AC |
550 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
551 | sp->tty->ops->write(sp->tty, &resync_cmd, 1); | |
1da177e4 LT |
552 | |
553 | ||
554 | /* Start resync timer again -- the TNC might be still absent */ | |
555 | ||
556 | del_timer(&sp->resync_t); | |
557 | sp->resync_t.data = (unsigned long) sp; | |
558 | sp->resync_t.function = resync_tnc; | |
559 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
560 | add_timer(&sp->resync_t); | |
561 | } | |
562 | ||
563 | static inline int tnc_init(struct sixpack *sp) | |
564 | { | |
565 | unsigned char inbyte = 0xe8; | |
566 | ||
567 | tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP); | |
568 | ||
f34d7a5b | 569 | sp->tty->ops->write(sp->tty, &inbyte, 1); |
1da177e4 LT |
570 | |
571 | del_timer(&sp->resync_t); | |
572 | sp->resync_t.data = (unsigned long) sp; | |
573 | sp->resync_t.function = resync_tnc; | |
574 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
575 | add_timer(&sp->resync_t); | |
576 | ||
577 | return 0; | |
578 | } | |
579 | ||
580 | /* | |
581 | * Open the high-level part of the 6pack channel. | |
582 | * This function is called by the TTY module when the | |
583 | * 6pack line discipline is called for. Because we are | |
584 | * sure the tty line exists, we only have to link it to | |
585 | * a free 6pcack channel... | |
586 | */ | |
587 | static int sixpack_open(struct tty_struct *tty) | |
588 | { | |
589 | char *rbuff = NULL, *xbuff = NULL; | |
590 | struct net_device *dev; | |
591 | struct sixpack *sp; | |
592 | unsigned long len; | |
593 | int err = 0; | |
594 | ||
595 | if (!capable(CAP_NET_ADMIN)) | |
596 | return -EPERM; | |
f34d7a5b AC |
597 | if (tty->ops->write == NULL) |
598 | return -EOPNOTSUPP; | |
1da177e4 LT |
599 | |
600 | dev = alloc_netdev(sizeof(struct sixpack), "sp%d", sp_setup); | |
601 | if (!dev) { | |
602 | err = -ENOMEM; | |
603 | goto out; | |
604 | } | |
605 | ||
606 | sp = netdev_priv(dev); | |
607 | sp->dev = dev; | |
608 | ||
609 | spin_lock_init(&sp->lock); | |
610 | atomic_set(&sp->refcnt, 1); | |
89d9f10d | 611 | sema_init(&sp->dead_sem, 0); |
1da177e4 LT |
612 | |
613 | /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */ | |
614 | ||
615 | len = dev->mtu * 2; | |
616 | ||
617 | rbuff = kmalloc(len + 4, GFP_KERNEL); | |
618 | xbuff = kmalloc(len + 4, GFP_KERNEL); | |
619 | ||
620 | if (rbuff == NULL || xbuff == NULL) { | |
621 | err = -ENOBUFS; | |
622 | goto out_free; | |
623 | } | |
624 | ||
625 | spin_lock_bh(&sp->lock); | |
626 | ||
627 | sp->tty = tty; | |
628 | ||
629 | sp->rbuff = rbuff; | |
630 | sp->xbuff = xbuff; | |
631 | ||
632 | sp->mtu = AX25_MTU + 73; | |
633 | sp->buffsize = len; | |
634 | sp->rcount = 0; | |
635 | sp->rx_count = 0; | |
636 | sp->rx_count_cooked = 0; | |
637 | sp->xleft = 0; | |
638 | ||
639 | sp->flags = 0; /* Clear ESCAPE & ERROR flags */ | |
640 | ||
641 | sp->duplex = 0; | |
642 | sp->tx_delay = SIXP_TXDELAY; | |
643 | sp->persistence = SIXP_PERSIST; | |
644 | sp->slottime = SIXP_SLOTTIME; | |
645 | sp->led_state = 0x60; | |
646 | sp->status = 1; | |
647 | sp->status1 = 1; | |
648 | sp->status2 = 0; | |
649 | sp->tx_enable = 0; | |
650 | ||
651 | netif_start_queue(dev); | |
652 | ||
653 | init_timer(&sp->tx_t); | |
84a2ea1c RB |
654 | sp->tx_t.function = sp_xmit_on_air; |
655 | sp->tx_t.data = (unsigned long) sp; | |
656 | ||
1da177e4 LT |
657 | init_timer(&sp->resync_t); |
658 | ||
659 | spin_unlock_bh(&sp->lock); | |
660 | ||
661 | /* Done. We have linked the TTY line to a channel. */ | |
662 | tty->disc_data = sp; | |
33f0f88f | 663 | tty->receive_room = 65536; |
1da177e4 LT |
664 | |
665 | /* Now we're ready to register. */ | |
666 | if (register_netdev(dev)) | |
667 | goto out_free; | |
668 | ||
669 | tnc_init(sp); | |
670 | ||
671 | return 0; | |
672 | ||
673 | out_free: | |
674 | kfree(xbuff); | |
675 | kfree(rbuff); | |
676 | ||
677 | if (dev) | |
678 | free_netdev(dev); | |
679 | ||
680 | out: | |
681 | return err; | |
682 | } | |
683 | ||
684 | ||
685 | /* | |
686 | * Close down a 6pack channel. | |
687 | * This means flushing out any pending queues, and then restoring the | |
688 | * TTY line discipline to what it was before it got hooked to 6pack | |
689 | * (which usually is TTY again). | |
690 | */ | |
691 | static void sixpack_close(struct tty_struct *tty) | |
692 | { | |
693 | struct sixpack *sp; | |
694 | ||
6e4e2f81 | 695 | write_lock_bh(&disc_data_lock); |
1da177e4 LT |
696 | sp = tty->disc_data; |
697 | tty->disc_data = NULL; | |
6e4e2f81 | 698 | write_unlock_bh(&disc_data_lock); |
79ea13ce | 699 | if (!sp) |
1da177e4 LT |
700 | return; |
701 | ||
702 | /* | |
703 | * We have now ensured that nobody can start using ap from now on, but | |
704 | * we have to wait for all existing users to finish. | |
705 | */ | |
706 | if (!atomic_dec_and_test(&sp->refcnt)) | |
707 | down(&sp->dead_sem); | |
708 | ||
709 | unregister_netdev(sp->dev); | |
710 | ||
711 | del_timer(&sp->tx_t); | |
712 | del_timer(&sp->resync_t); | |
713 | ||
714 | /* Free all 6pack frame buffers. */ | |
715 | kfree(sp->rbuff); | |
716 | kfree(sp->xbuff); | |
717 | } | |
718 | ||
719 | /* Perform I/O control on an active 6pack channel. */ | |
720 | static int sixpack_ioctl(struct tty_struct *tty, struct file *file, | |
721 | unsigned int cmd, unsigned long arg) | |
722 | { | |
723 | struct sixpack *sp = sp_get(tty); | |
0397a264 | 724 | struct net_device *dev; |
1da177e4 LT |
725 | unsigned int tmp, err; |
726 | ||
727 | if (!sp) | |
728 | return -ENXIO; | |
0397a264 | 729 | dev = sp->dev; |
1da177e4 LT |
730 | |
731 | switch(cmd) { | |
732 | case SIOCGIFNAME: | |
733 | err = copy_to_user((void __user *) arg, dev->name, | |
734 | strlen(dev->name) + 1) ? -EFAULT : 0; | |
735 | break; | |
736 | ||
737 | case SIOCGIFENCAP: | |
738 | err = put_user(0, (int __user *) arg); | |
739 | break; | |
740 | ||
741 | case SIOCSIFENCAP: | |
742 | if (get_user(tmp, (int __user *) arg)) { | |
743 | err = -EFAULT; | |
744 | break; | |
745 | } | |
746 | ||
747 | sp->mode = tmp; | |
748 | dev->addr_len = AX25_ADDR_LEN; | |
749 | dev->hard_header_len = AX25_KISS_HEADER_LEN + | |
750 | AX25_MAX_HEADER_LEN + 3; | |
751 | dev->type = ARPHRD_AX25; | |
752 | ||
753 | err = 0; | |
754 | break; | |
755 | ||
756 | case SIOCSIFHWADDR: { | |
757 | char addr[AX25_ADDR_LEN]; | |
758 | ||
759 | if (copy_from_user(&addr, | |
760 | (void __user *) arg, AX25_ADDR_LEN)) { | |
d0127539 AC |
761 | err = -EFAULT; |
762 | break; | |
763 | } | |
1da177e4 | 764 | |
d0127539 AC |
765 | netif_tx_lock_bh(dev); |
766 | memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN); | |
767 | netif_tx_unlock_bh(dev); | |
1da177e4 | 768 | |
d0127539 AC |
769 | err = 0; |
770 | break; | |
771 | } | |
1da177e4 LT |
772 | |
773 | default: | |
d0127539 | 774 | err = tty_mode_ioctl(tty, file, cmd, arg); |
1da177e4 LT |
775 | } |
776 | ||
777 | sp_put(sp); | |
778 | ||
779 | return err; | |
780 | } | |
781 | ||
9646e7ce AB |
782 | #ifdef CONFIG_COMPAT |
783 | static long sixpack_compat_ioctl(struct tty_struct * tty, struct file * file, | |
784 | unsigned int cmd, unsigned long arg) | |
785 | { | |
786 | switch (cmd) { | |
787 | case SIOCGIFNAME: | |
788 | case SIOCGIFENCAP: | |
789 | case SIOCSIFENCAP: | |
790 | case SIOCSIFHWADDR: | |
791 | return sixpack_ioctl(tty, file, cmd, | |
792 | (unsigned long)compat_ptr(arg)); | |
793 | } | |
794 | ||
795 | return -ENOIOCTLCMD; | |
796 | } | |
797 | #endif | |
798 | ||
a352def2 | 799 | static struct tty_ldisc_ops sp_ldisc = { |
1da177e4 LT |
800 | .owner = THIS_MODULE, |
801 | .magic = TTY_LDISC_MAGIC, | |
802 | .name = "6pack", | |
803 | .open = sixpack_open, | |
804 | .close = sixpack_close, | |
805 | .ioctl = sixpack_ioctl, | |
9646e7ce AB |
806 | #ifdef CONFIG_COMPAT |
807 | .compat_ioctl = sixpack_compat_ioctl, | |
808 | #endif | |
1da177e4 | 809 | .receive_buf = sixpack_receive_buf, |
1da177e4 LT |
810 | .write_wakeup = sixpack_write_wakeup, |
811 | }; | |
812 | ||
813 | /* Initialize 6pack control device -- register 6pack line discipline */ | |
814 | ||
eb33ae24 | 815 | static const char msg_banner[] __initdata = KERN_INFO \ |
1da177e4 | 816 | "AX.25: 6pack driver, " SIXPACK_VERSION "\n"; |
eb33ae24 | 817 | static const char msg_regfail[] __initdata = KERN_ERR \ |
1da177e4 LT |
818 | "6pack: can't register line discipline (err = %d)\n"; |
819 | ||
820 | static int __init sixpack_init_driver(void) | |
821 | { | |
822 | int status; | |
823 | ||
824 | printk(msg_banner); | |
825 | ||
826 | /* Register the provided line protocol discipline */ | |
827 | if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0) | |
828 | printk(msg_regfail, status); | |
829 | ||
830 | return status; | |
831 | } | |
832 | ||
833 | static const char msg_unregfail[] __exitdata = KERN_ERR \ | |
834 | "6pack: can't unregister line discipline (err = %d)\n"; | |
835 | ||
836 | static void __exit sixpack_exit_driver(void) | |
837 | { | |
838 | int ret; | |
839 | ||
64ccd715 | 840 | if ((ret = tty_unregister_ldisc(N_6PACK))) |
1da177e4 LT |
841 | printk(msg_unregfail, ret); |
842 | } | |
843 | ||
844 | /* encode an AX.25 packet into 6pack */ | |
845 | ||
846 | static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw, | |
847 | int length, unsigned char tx_delay) | |
848 | { | |
849 | int count = 0; | |
850 | unsigned char checksum = 0, buf[400]; | |
851 | int raw_count = 0; | |
852 | ||
853 | tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK; | |
854 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
855 | ||
856 | buf[0] = tx_delay; | |
857 | for (count = 1; count < length; count++) | |
858 | buf[count] = tx_buf[count]; | |
859 | ||
860 | for (count = 0; count < length; count++) | |
861 | checksum += buf[count]; | |
862 | buf[length] = (unsigned char) 0xff - checksum; | |
863 | ||
864 | for (count = 0; count <= length; count++) { | |
865 | if ((count % 3) == 0) { | |
866 | tx_buf_raw[raw_count++] = (buf[count] & 0x3f); | |
867 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30); | |
868 | } else if ((count % 3) == 1) { | |
869 | tx_buf_raw[raw_count++] |= (buf[count] & 0x0f); | |
870 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c); | |
871 | } else { | |
872 | tx_buf_raw[raw_count++] |= (buf[count] & 0x03); | |
873 | tx_buf_raw[raw_count++] = (buf[count] >> 2); | |
874 | } | |
875 | } | |
876 | if ((length % 3) != 2) | |
877 | raw_count++; | |
878 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
879 | return raw_count; | |
880 | } | |
881 | ||
882 | /* decode 4 sixpack-encoded bytes into 3 data bytes */ | |
883 | ||
884 | static void decode_data(struct sixpack *sp, unsigned char inbyte) | |
885 | { | |
886 | unsigned char *buf; | |
887 | ||
888 | if (sp->rx_count != 3) { | |
889 | sp->raw_buf[sp->rx_count++] = inbyte; | |
890 | ||
891 | return; | |
892 | } | |
893 | ||
894 | buf = sp->raw_buf; | |
895 | sp->cooked_buf[sp->rx_count_cooked++] = | |
896 | buf[0] | ((buf[1] << 2) & 0xc0); | |
897 | sp->cooked_buf[sp->rx_count_cooked++] = | |
898 | (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0); | |
899 | sp->cooked_buf[sp->rx_count_cooked++] = | |
900 | (buf[2] & 0x03) | (inbyte << 2); | |
901 | sp->rx_count = 0; | |
902 | } | |
903 | ||
904 | /* identify and execute a 6pack priority command byte */ | |
905 | ||
906 | static void decode_prio_command(struct sixpack *sp, unsigned char cmd) | |
907 | { | |
908 | unsigned char channel; | |
909 | int actual; | |
910 | ||
911 | channel = cmd & SIXP_CHN_MASK; | |
912 | if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */ | |
913 | ||
914 | /* RX and DCD flags can only be set in the same prio command, | |
915 | if the DCD flag has been set without the RX flag in the previous | |
916 | prio command. If DCD has not been set before, something in the | |
917 | transmission has gone wrong. In this case, RX and DCD are | |
918 | cleared in order to prevent the decode_data routine from | |
919 | reading further data that might be corrupt. */ | |
920 | ||
921 | if (((sp->status & SIXP_DCD_MASK) == 0) && | |
922 | ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) { | |
923 | if (sp->status != 1) | |
924 | printk(KERN_DEBUG "6pack: protocol violation\n"); | |
925 | else | |
926 | sp->status = 0; | |
95f6134e | 927 | cmd &= ~SIXP_RX_DCD_MASK; |
1da177e4 LT |
928 | } |
929 | sp->status = cmd & SIXP_PRIO_DATA_MASK; | |
930 | } else { /* output watchdog char if idle */ | |
931 | if ((sp->status2 != 0) && (sp->duplex == 1)) { | |
932 | sp->led_state = 0x70; | |
f34d7a5b | 933 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 934 | sp->tx_enable = 1; |
f34d7a5b | 935 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); |
1da177e4 LT |
936 | sp->xleft -= actual; |
937 | sp->xhead += actual; | |
938 | sp->led_state = 0x60; | |
939 | sp->status2 = 0; | |
940 | ||
941 | } | |
942 | } | |
943 | ||
944 | /* needed to trigger the TNC watchdog */ | |
f34d7a5b | 945 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
946 | |
947 | /* if the state byte has been received, the TNC is present, | |
948 | so the resync timer can be reset. */ | |
949 | ||
950 | if (sp->tnc_state == TNC_IN_SYNC) { | |
951 | del_timer(&sp->resync_t); | |
952 | sp->resync_t.data = (unsigned long) sp; | |
953 | sp->resync_t.function = resync_tnc; | |
954 | sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT; | |
955 | add_timer(&sp->resync_t); | |
956 | } | |
957 | ||
958 | sp->status1 = cmd & SIXP_PRIO_DATA_MASK; | |
959 | } | |
960 | ||
961 | /* identify and execute a standard 6pack command byte */ | |
962 | ||
963 | static void decode_std_command(struct sixpack *sp, unsigned char cmd) | |
964 | { | |
965 | unsigned char checksum = 0, rest = 0, channel; | |
966 | short i; | |
967 | ||
968 | channel = cmd & SIXP_CHN_MASK; | |
969 | switch (cmd & SIXP_CMD_MASK) { /* normal command */ | |
970 | case SIXP_SEOF: | |
971 | if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) { | |
972 | if ((sp->status & SIXP_RX_DCD_MASK) == | |
973 | SIXP_RX_DCD_MASK) { | |
974 | sp->led_state = 0x68; | |
f34d7a5b | 975 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
976 | } |
977 | } else { | |
978 | sp->led_state = 0x60; | |
979 | /* fill trailing bytes with zeroes */ | |
f34d7a5b | 980 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
981 | rest = sp->rx_count; |
982 | if (rest != 0) | |
983 | for (i = rest; i <= 3; i++) | |
984 | decode_data(sp, 0); | |
985 | if (rest == 2) | |
986 | sp->rx_count_cooked -= 2; | |
987 | else if (rest == 3) | |
988 | sp->rx_count_cooked -= 1; | |
989 | for (i = 0; i < sp->rx_count_cooked; i++) | |
990 | checksum += sp->cooked_buf[i]; | |
991 | if (checksum != SIXP_CHKSUM) { | |
992 | printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum); | |
993 | } else { | |
994 | sp->rcount = sp->rx_count_cooked-2; | |
995 | sp_bump(sp, 0); | |
996 | } | |
997 | sp->rx_count_cooked = 0; | |
998 | } | |
999 | break; | |
1000 | case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n"); | |
1001 | break; | |
1002 | case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n"); | |
1003 | break; | |
1004 | case SIXP_RX_BUF_OVL: | |
1005 | printk(KERN_DEBUG "6pack: RX buffer overflow\n"); | |
1006 | } | |
1007 | } | |
1008 | ||
1009 | /* decode a 6pack packet */ | |
1010 | ||
1011 | static void | |
1012 | sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count) | |
1013 | { | |
1014 | unsigned char inbyte; | |
1015 | int count1; | |
1016 | ||
1017 | for (count1 = 0; count1 < count; count1++) { | |
1018 | inbyte = pre_rbuff[count1]; | |
1019 | if (inbyte == SIXP_FOUND_TNC) { | |
1020 | tnc_set_sync_state(sp, TNC_IN_SYNC); | |
1021 | del_timer(&sp->resync_t); | |
1022 | } | |
1023 | if ((inbyte & SIXP_PRIO_CMD_MASK) != 0) | |
1024 | decode_prio_command(sp, inbyte); | |
1025 | else if ((inbyte & SIXP_STD_CMD_MASK) != 0) | |
1026 | decode_std_command(sp, inbyte); | |
1027 | else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK) | |
1028 | decode_data(sp, inbyte); | |
1029 | } | |
1030 | } | |
1031 | ||
1032 | MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>"); | |
1033 | MODULE_DESCRIPTION("6pack driver for AX.25"); | |
1034 | MODULE_LICENSE("GPL"); | |
1035 | MODULE_ALIAS_LDISC(N_6PACK); | |
1036 | ||
1037 | module_init(sixpack_init_driver); | |
1038 | module_exit(sixpack_exit_driver); |