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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 | 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 | ||
1d5da757 EB |
250 | if (skb->protocol == htons(ETH_P_IP)) |
251 | return ax25_ip_xmit(skb); | |
252 | ||
1da177e4 LT |
253 | spin_lock_bh(&sp->lock); |
254 | /* We were not busy, so we are now... :-) */ | |
255 | netif_stop_queue(dev); | |
de0561c4 | 256 | dev->stats.tx_bytes += skb->len; |
1da177e4 LT |
257 | sp_encaps(sp, skb->data, skb->len); |
258 | spin_unlock_bh(&sp->lock); | |
259 | ||
260 | dev_kfree_skb(skb); | |
261 | ||
6ed10654 | 262 | return NETDEV_TX_OK; |
1da177e4 LT |
263 | } |
264 | ||
265 | static int sp_open_dev(struct net_device *dev) | |
266 | { | |
267 | struct sixpack *sp = netdev_priv(dev); | |
268 | ||
269 | if (sp->tty == NULL) | |
270 | return -ENODEV; | |
271 | return 0; | |
272 | } | |
273 | ||
274 | /* Close the low-level part of the 6pack channel. */ | |
275 | static int sp_close(struct net_device *dev) | |
276 | { | |
277 | struct sixpack *sp = netdev_priv(dev); | |
278 | ||
279 | spin_lock_bh(&sp->lock); | |
280 | if (sp->tty) { | |
281 | /* TTY discipline is running. */ | |
282 | clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); | |
283 | } | |
284 | netif_stop_queue(dev); | |
285 | spin_unlock_bh(&sp->lock); | |
286 | ||
287 | return 0; | |
288 | } | |
289 | ||
1da177e4 LT |
290 | static int sp_set_mac_address(struct net_device *dev, void *addr) |
291 | { | |
292 | struct sockaddr_ax25 *sa = addr; | |
293 | ||
932ff279 | 294 | netif_tx_lock_bh(dev); |
e308a5d8 | 295 | netif_addr_lock(dev); |
1da177e4 | 296 | memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); |
e308a5d8 | 297 | netif_addr_unlock(dev); |
932ff279 | 298 | netif_tx_unlock_bh(dev); |
1da177e4 LT |
299 | |
300 | return 0; | |
301 | } | |
302 | ||
b3672a73 SH |
303 | static const struct net_device_ops sp_netdev_ops = { |
304 | .ndo_open = sp_open_dev, | |
305 | .ndo_stop = sp_close, | |
306 | .ndo_start_xmit = sp_xmit, | |
307 | .ndo_set_mac_address = sp_set_mac_address, | |
308 | }; | |
309 | ||
1da177e4 LT |
310 | static void sp_setup(struct net_device *dev) |
311 | { | |
1da177e4 | 312 | /* Finish setting up the DEVICE info. */ |
b3672a73 | 313 | dev->netdev_ops = &sp_netdev_ops; |
1da177e4 | 314 | dev->destructor = free_netdev; |
b3672a73 | 315 | dev->mtu = SIXP_MTU; |
1da177e4 | 316 | dev->hard_header_len = AX25_MAX_HEADER_LEN; |
204d2dca | 317 | dev->header_ops = &ax25_header_ops; |
3b04ddde | 318 | |
1da177e4 LT |
319 | dev->addr_len = AX25_ADDR_LEN; |
320 | dev->type = ARPHRD_AX25; | |
321 | dev->tx_queue_len = 10; | |
1da177e4 LT |
322 | |
323 | /* Only activated in AX.25 mode */ | |
15b1c0e8 RB |
324 | memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); |
325 | memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); | |
1da177e4 | 326 | |
1da177e4 LT |
327 | dev->flags = 0; |
328 | } | |
329 | ||
330 | /* Send one completely decapsulated IP datagram to the IP layer. */ | |
331 | ||
332 | /* | |
333 | * This is the routine that sends the received data to the kernel AX.25. | |
334 | * 'cmd' is the KISS command. For AX.25 data, it is zero. | |
335 | */ | |
336 | ||
337 | static void sp_bump(struct sixpack *sp, char cmd) | |
338 | { | |
339 | struct sk_buff *skb; | |
340 | int count; | |
341 | unsigned char *ptr; | |
342 | ||
343 | count = sp->rcount + 1; | |
344 | ||
de0561c4 | 345 | sp->dev->stats.rx_bytes += count; |
1da177e4 LT |
346 | |
347 | if ((skb = dev_alloc_skb(count)) == NULL) | |
348 | goto out_mem; | |
349 | ||
1da177e4 LT |
350 | ptr = skb_put(skb, count); |
351 | *ptr++ = cmd; /* KISS command */ | |
352 | ||
353 | memcpy(ptr, sp->cooked_buf + 1, count); | |
56cb5156 | 354 | skb->protocol = ax25_type_trans(skb, sp->dev); |
1da177e4 | 355 | netif_rx(skb); |
de0561c4 | 356 | sp->dev->stats.rx_packets++; |
1da177e4 LT |
357 | |
358 | return; | |
359 | ||
360 | out_mem: | |
de0561c4 | 361 | sp->dev->stats.rx_dropped++; |
1da177e4 LT |
362 | } |
363 | ||
364 | ||
365 | /* ----------------------------------------------------------------------- */ | |
366 | ||
367 | /* | |
368 | * We have a potential race on dereferencing tty->disc_data, because the tty | |
369 | * layer provides no locking at all - thus one cpu could be running | |
370 | * sixpack_receive_buf while another calls sixpack_close, which zeroes | |
371 | * tty->disc_data and frees the memory that sixpack_receive_buf is using. The | |
372 | * best way to fix this is to use a rwlock in the tty struct, but for now we | |
373 | * use a single global rwlock for all ttys in ppp line discipline. | |
374 | */ | |
375 | static DEFINE_RWLOCK(disc_data_lock); | |
376 | ||
377 | static struct sixpack *sp_get(struct tty_struct *tty) | |
378 | { | |
379 | struct sixpack *sp; | |
380 | ||
381 | read_lock(&disc_data_lock); | |
382 | sp = tty->disc_data; | |
383 | if (sp) | |
384 | atomic_inc(&sp->refcnt); | |
385 | read_unlock(&disc_data_lock); | |
386 | ||
387 | return sp; | |
388 | } | |
389 | ||
390 | static void sp_put(struct sixpack *sp) | |
391 | { | |
392 | if (atomic_dec_and_test(&sp->refcnt)) | |
393 | up(&sp->dead_sem); | |
394 | } | |
395 | ||
396 | /* | |
397 | * Called by the TTY driver when there's room for more data. If we have | |
398 | * more packets to send, we send them here. | |
399 | */ | |
400 | static void sixpack_write_wakeup(struct tty_struct *tty) | |
401 | { | |
402 | struct sixpack *sp = sp_get(tty); | |
403 | int actual; | |
404 | ||
405 | if (!sp) | |
406 | return; | |
407 | if (sp->xleft <= 0) { | |
408 | /* Now serial buffer is almost free & we can start | |
409 | * transmission of another packet */ | |
de0561c4 | 410 | sp->dev->stats.tx_packets++; |
1da177e4 LT |
411 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
412 | sp->tx_enable = 0; | |
413 | netif_wake_queue(sp->dev); | |
414 | goto out; | |
415 | } | |
416 | ||
417 | if (sp->tx_enable) { | |
f34d7a5b | 418 | actual = tty->ops->write(tty, sp->xhead, sp->xleft); |
1da177e4 LT |
419 | sp->xleft -= actual; |
420 | sp->xhead += actual; | |
421 | } | |
422 | ||
423 | out: | |
424 | sp_put(sp); | |
425 | } | |
426 | ||
427 | /* ----------------------------------------------------------------------- */ | |
428 | ||
1da177e4 LT |
429 | /* |
430 | * Handle the 'receiver data ready' interrupt. | |
431 | * This function is called by the 'tty_io' module in the kernel when | |
432 | * a block of 6pack data has been received, which can now be decapsulated | |
433 | * and sent on to some IP layer for further processing. | |
434 | */ | |
55db4c64 | 435 | static void sixpack_receive_buf(struct tty_struct *tty, |
1da177e4 LT |
436 | const unsigned char *cp, char *fp, int count) |
437 | { | |
438 | struct sixpack *sp; | |
439 | unsigned char buf[512]; | |
440 | int count1; | |
441 | ||
442 | if (!count) | |
55db4c64 | 443 | return; |
1da177e4 LT |
444 | |
445 | sp = sp_get(tty); | |
446 | if (!sp) | |
55db4c64 | 447 | return; |
1da177e4 LT |
448 | |
449 | memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf)); | |
450 | ||
451 | /* Read the characters out of the buffer */ | |
452 | ||
453 | count1 = count; | |
454 | while (count) { | |
455 | count--; | |
456 | if (fp && *fp++) { | |
457 | if (!test_and_set_bit(SIXPF_ERROR, &sp->flags)) | |
de0561c4 | 458 | sp->dev->stats.rx_errors++; |
1da177e4 LT |
459 | continue; |
460 | } | |
461 | } | |
462 | sixpack_decode(sp, buf, count1); | |
463 | ||
464 | sp_put(sp); | |
39c2e60f | 465 | tty_unthrottle(tty); |
1da177e4 LT |
466 | } |
467 | ||
468 | /* | |
469 | * Try to resync the TNC. Called by the resync timer defined in | |
470 | * decode_prio_command | |
471 | */ | |
472 | ||
473 | #define TNC_UNINITIALIZED 0 | |
474 | #define TNC_UNSYNC_STARTUP 1 | |
475 | #define TNC_UNSYNCED 2 | |
476 | #define TNC_IN_SYNC 3 | |
477 | ||
478 | static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
479 | { | |
480 | char *msg; | |
481 | ||
482 | switch (new_tnc_state) { | |
483 | default: /* gcc oh piece-o-crap ... */ | |
484 | case TNC_UNSYNC_STARTUP: | |
485 | msg = "Synchronizing with TNC"; | |
486 | break; | |
487 | case TNC_UNSYNCED: | |
488 | msg = "Lost synchronization with TNC\n"; | |
489 | break; | |
490 | case TNC_IN_SYNC: | |
491 | msg = "Found TNC"; | |
492 | break; | |
493 | } | |
494 | ||
495 | sp->tnc_state = new_tnc_state; | |
496 | printk(KERN_INFO "%s: %s\n", sp->dev->name, msg); | |
497 | } | |
498 | ||
499 | static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) | |
500 | { | |
501 | int old_tnc_state = sp->tnc_state; | |
502 | ||
503 | if (old_tnc_state != new_tnc_state) | |
504 | __tnc_set_sync_state(sp, new_tnc_state); | |
505 | } | |
506 | ||
507 | static void resync_tnc(unsigned long channel) | |
508 | { | |
509 | struct sixpack *sp = (struct sixpack *) channel; | |
510 | static char resync_cmd = 0xe8; | |
511 | ||
512 | /* clear any data that might have been received */ | |
513 | ||
514 | sp->rx_count = 0; | |
515 | sp->rx_count_cooked = 0; | |
516 | ||
517 | /* reset state machine */ | |
518 | ||
519 | sp->status = 1; | |
520 | sp->status1 = 1; | |
521 | sp->status2 = 0; | |
522 | ||
523 | /* resync the TNC */ | |
524 | ||
525 | sp->led_state = 0x60; | |
f34d7a5b AC |
526 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
527 | sp->tty->ops->write(sp->tty, &resync_cmd, 1); | |
1da177e4 LT |
528 | |
529 | ||
530 | /* Start resync timer again -- the TNC might be still absent */ | |
531 | ||
532 | del_timer(&sp->resync_t); | |
533 | sp->resync_t.data = (unsigned long) sp; | |
534 | sp->resync_t.function = resync_tnc; | |
535 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
536 | add_timer(&sp->resync_t); | |
537 | } | |
538 | ||
539 | static inline int tnc_init(struct sixpack *sp) | |
540 | { | |
541 | unsigned char inbyte = 0xe8; | |
542 | ||
543 | tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP); | |
544 | ||
f34d7a5b | 545 | sp->tty->ops->write(sp->tty, &inbyte, 1); |
1da177e4 LT |
546 | |
547 | del_timer(&sp->resync_t); | |
548 | sp->resync_t.data = (unsigned long) sp; | |
549 | sp->resync_t.function = resync_tnc; | |
550 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; | |
551 | add_timer(&sp->resync_t); | |
552 | ||
553 | return 0; | |
554 | } | |
555 | ||
556 | /* | |
557 | * Open the high-level part of the 6pack channel. | |
558 | * This function is called by the TTY module when the | |
559 | * 6pack line discipline is called for. Because we are | |
560 | * sure the tty line exists, we only have to link it to | |
561 | * a free 6pcack channel... | |
562 | */ | |
563 | static int sixpack_open(struct tty_struct *tty) | |
564 | { | |
565 | char *rbuff = NULL, *xbuff = NULL; | |
566 | struct net_device *dev; | |
567 | struct sixpack *sp; | |
568 | unsigned long len; | |
569 | int err = 0; | |
570 | ||
571 | if (!capable(CAP_NET_ADMIN)) | |
572 | return -EPERM; | |
f34d7a5b AC |
573 | if (tty->ops->write == NULL) |
574 | return -EOPNOTSUPP; | |
1da177e4 | 575 | |
c835a677 TG |
576 | dev = alloc_netdev(sizeof(struct sixpack), "sp%d", NET_NAME_UNKNOWN, |
577 | sp_setup); | |
1da177e4 LT |
578 | if (!dev) { |
579 | err = -ENOMEM; | |
580 | goto out; | |
581 | } | |
582 | ||
583 | sp = netdev_priv(dev); | |
584 | sp->dev = dev; | |
585 | ||
586 | spin_lock_init(&sp->lock); | |
587 | atomic_set(&sp->refcnt, 1); | |
89d9f10d | 588 | sema_init(&sp->dead_sem, 0); |
1da177e4 LT |
589 | |
590 | /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */ | |
591 | ||
592 | len = dev->mtu * 2; | |
593 | ||
594 | rbuff = kmalloc(len + 4, GFP_KERNEL); | |
595 | xbuff = kmalloc(len + 4, GFP_KERNEL); | |
596 | ||
597 | if (rbuff == NULL || xbuff == NULL) { | |
598 | err = -ENOBUFS; | |
599 | goto out_free; | |
600 | } | |
601 | ||
602 | spin_lock_bh(&sp->lock); | |
603 | ||
604 | sp->tty = tty; | |
605 | ||
606 | sp->rbuff = rbuff; | |
607 | sp->xbuff = xbuff; | |
608 | ||
609 | sp->mtu = AX25_MTU + 73; | |
610 | sp->buffsize = len; | |
611 | sp->rcount = 0; | |
612 | sp->rx_count = 0; | |
613 | sp->rx_count_cooked = 0; | |
614 | sp->xleft = 0; | |
615 | ||
616 | sp->flags = 0; /* Clear ESCAPE & ERROR flags */ | |
617 | ||
618 | sp->duplex = 0; | |
619 | sp->tx_delay = SIXP_TXDELAY; | |
620 | sp->persistence = SIXP_PERSIST; | |
621 | sp->slottime = SIXP_SLOTTIME; | |
622 | sp->led_state = 0x60; | |
623 | sp->status = 1; | |
624 | sp->status1 = 1; | |
625 | sp->status2 = 0; | |
626 | sp->tx_enable = 0; | |
627 | ||
628 | netif_start_queue(dev); | |
629 | ||
630 | init_timer(&sp->tx_t); | |
84a2ea1c RB |
631 | sp->tx_t.function = sp_xmit_on_air; |
632 | sp->tx_t.data = (unsigned long) sp; | |
633 | ||
1da177e4 LT |
634 | init_timer(&sp->resync_t); |
635 | ||
636 | spin_unlock_bh(&sp->lock); | |
637 | ||
638 | /* Done. We have linked the TTY line to a channel. */ | |
639 | tty->disc_data = sp; | |
33f0f88f | 640 | tty->receive_room = 65536; |
1da177e4 LT |
641 | |
642 | /* Now we're ready to register. */ | |
769f01ef JL |
643 | err = register_netdev(dev); |
644 | if (err) | |
1da177e4 LT |
645 | goto out_free; |
646 | ||
647 | tnc_init(sp); | |
648 | ||
649 | return 0; | |
650 | ||
651 | out_free: | |
652 | kfree(xbuff); | |
653 | kfree(rbuff); | |
654 | ||
ec5a0ec1 | 655 | free_netdev(dev); |
1da177e4 LT |
656 | |
657 | out: | |
658 | return err; | |
659 | } | |
660 | ||
661 | ||
662 | /* | |
663 | * Close down a 6pack channel. | |
664 | * This means flushing out any pending queues, and then restoring the | |
665 | * TTY line discipline to what it was before it got hooked to 6pack | |
666 | * (which usually is TTY again). | |
667 | */ | |
668 | static void sixpack_close(struct tty_struct *tty) | |
669 | { | |
670 | struct sixpack *sp; | |
671 | ||
6e4e2f81 | 672 | write_lock_bh(&disc_data_lock); |
1da177e4 LT |
673 | sp = tty->disc_data; |
674 | tty->disc_data = NULL; | |
6e4e2f81 | 675 | write_unlock_bh(&disc_data_lock); |
79ea13ce | 676 | if (!sp) |
1da177e4 LT |
677 | return; |
678 | ||
679 | /* | |
680 | * We have now ensured that nobody can start using ap from now on, but | |
681 | * we have to wait for all existing users to finish. | |
682 | */ | |
683 | if (!atomic_dec_and_test(&sp->refcnt)) | |
684 | down(&sp->dead_sem); | |
685 | ||
686 | unregister_netdev(sp->dev); | |
687 | ||
688 | del_timer(&sp->tx_t); | |
689 | del_timer(&sp->resync_t); | |
690 | ||
691 | /* Free all 6pack frame buffers. */ | |
692 | kfree(sp->rbuff); | |
693 | kfree(sp->xbuff); | |
694 | } | |
695 | ||
696 | /* Perform I/O control on an active 6pack channel. */ | |
697 | static int sixpack_ioctl(struct tty_struct *tty, struct file *file, | |
698 | unsigned int cmd, unsigned long arg) | |
699 | { | |
700 | struct sixpack *sp = sp_get(tty); | |
0397a264 | 701 | struct net_device *dev; |
1da177e4 LT |
702 | unsigned int tmp, err; |
703 | ||
704 | if (!sp) | |
705 | return -ENXIO; | |
0397a264 | 706 | dev = sp->dev; |
1da177e4 LT |
707 | |
708 | switch(cmd) { | |
709 | case SIOCGIFNAME: | |
710 | err = copy_to_user((void __user *) arg, dev->name, | |
711 | strlen(dev->name) + 1) ? -EFAULT : 0; | |
712 | break; | |
713 | ||
714 | case SIOCGIFENCAP: | |
715 | err = put_user(0, (int __user *) arg); | |
716 | break; | |
717 | ||
718 | case SIOCSIFENCAP: | |
719 | if (get_user(tmp, (int __user *) arg)) { | |
720 | err = -EFAULT; | |
721 | break; | |
722 | } | |
723 | ||
724 | sp->mode = tmp; | |
725 | dev->addr_len = AX25_ADDR_LEN; | |
726 | dev->hard_header_len = AX25_KISS_HEADER_LEN + | |
727 | AX25_MAX_HEADER_LEN + 3; | |
728 | dev->type = ARPHRD_AX25; | |
729 | ||
730 | err = 0; | |
731 | break; | |
732 | ||
733 | case SIOCSIFHWADDR: { | |
734 | char addr[AX25_ADDR_LEN]; | |
735 | ||
736 | if (copy_from_user(&addr, | |
737 | (void __user *) arg, AX25_ADDR_LEN)) { | |
d0127539 AC |
738 | err = -EFAULT; |
739 | break; | |
740 | } | |
1da177e4 | 741 | |
d0127539 AC |
742 | netif_tx_lock_bh(dev); |
743 | memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN); | |
744 | netif_tx_unlock_bh(dev); | |
1da177e4 | 745 | |
d0127539 AC |
746 | err = 0; |
747 | break; | |
748 | } | |
1da177e4 LT |
749 | |
750 | default: | |
d0127539 | 751 | err = tty_mode_ioctl(tty, file, cmd, arg); |
1da177e4 LT |
752 | } |
753 | ||
754 | sp_put(sp); | |
755 | ||
756 | return err; | |
757 | } | |
758 | ||
9646e7ce AB |
759 | #ifdef CONFIG_COMPAT |
760 | static long sixpack_compat_ioctl(struct tty_struct * tty, struct file * file, | |
761 | unsigned int cmd, unsigned long arg) | |
762 | { | |
763 | switch (cmd) { | |
764 | case SIOCGIFNAME: | |
765 | case SIOCGIFENCAP: | |
766 | case SIOCSIFENCAP: | |
767 | case SIOCSIFHWADDR: | |
768 | return sixpack_ioctl(tty, file, cmd, | |
769 | (unsigned long)compat_ptr(arg)); | |
770 | } | |
771 | ||
772 | return -ENOIOCTLCMD; | |
773 | } | |
774 | #endif | |
775 | ||
a352def2 | 776 | static struct tty_ldisc_ops sp_ldisc = { |
1da177e4 LT |
777 | .owner = THIS_MODULE, |
778 | .magic = TTY_LDISC_MAGIC, | |
779 | .name = "6pack", | |
780 | .open = sixpack_open, | |
781 | .close = sixpack_close, | |
782 | .ioctl = sixpack_ioctl, | |
9646e7ce AB |
783 | #ifdef CONFIG_COMPAT |
784 | .compat_ioctl = sixpack_compat_ioctl, | |
785 | #endif | |
1da177e4 | 786 | .receive_buf = sixpack_receive_buf, |
1da177e4 LT |
787 | .write_wakeup = sixpack_write_wakeup, |
788 | }; | |
789 | ||
790 | /* Initialize 6pack control device -- register 6pack line discipline */ | |
791 | ||
c477ebd8 | 792 | static const char msg_banner[] __initconst = KERN_INFO \ |
1da177e4 | 793 | "AX.25: 6pack driver, " SIXPACK_VERSION "\n"; |
c477ebd8 | 794 | static const char msg_regfail[] __initconst = KERN_ERR \ |
1da177e4 LT |
795 | "6pack: can't register line discipline (err = %d)\n"; |
796 | ||
797 | static int __init sixpack_init_driver(void) | |
798 | { | |
799 | int status; | |
800 | ||
801 | printk(msg_banner); | |
802 | ||
803 | /* Register the provided line protocol discipline */ | |
804 | if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0) | |
805 | printk(msg_regfail, status); | |
806 | ||
807 | return status; | |
808 | } | |
809 | ||
afa8c78b | 810 | static const char msg_unregfail[] = KERN_ERR \ |
1da177e4 LT |
811 | "6pack: can't unregister line discipline (err = %d)\n"; |
812 | ||
813 | static void __exit sixpack_exit_driver(void) | |
814 | { | |
815 | int ret; | |
816 | ||
64ccd715 | 817 | if ((ret = tty_unregister_ldisc(N_6PACK))) |
1da177e4 LT |
818 | printk(msg_unregfail, ret); |
819 | } | |
820 | ||
821 | /* encode an AX.25 packet into 6pack */ | |
822 | ||
823 | static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw, | |
824 | int length, unsigned char tx_delay) | |
825 | { | |
826 | int count = 0; | |
827 | unsigned char checksum = 0, buf[400]; | |
828 | int raw_count = 0; | |
829 | ||
830 | tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK; | |
831 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
832 | ||
833 | buf[0] = tx_delay; | |
834 | for (count = 1; count < length; count++) | |
835 | buf[count] = tx_buf[count]; | |
836 | ||
837 | for (count = 0; count < length; count++) | |
838 | checksum += buf[count]; | |
839 | buf[length] = (unsigned char) 0xff - checksum; | |
840 | ||
841 | for (count = 0; count <= length; count++) { | |
842 | if ((count % 3) == 0) { | |
843 | tx_buf_raw[raw_count++] = (buf[count] & 0x3f); | |
844 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30); | |
845 | } else if ((count % 3) == 1) { | |
846 | tx_buf_raw[raw_count++] |= (buf[count] & 0x0f); | |
847 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c); | |
848 | } else { | |
849 | tx_buf_raw[raw_count++] |= (buf[count] & 0x03); | |
850 | tx_buf_raw[raw_count++] = (buf[count] >> 2); | |
851 | } | |
852 | } | |
853 | if ((length % 3) != 2) | |
854 | raw_count++; | |
855 | tx_buf_raw[raw_count++] = SIXP_SEOF; | |
856 | return raw_count; | |
857 | } | |
858 | ||
859 | /* decode 4 sixpack-encoded bytes into 3 data bytes */ | |
860 | ||
861 | static void decode_data(struct sixpack *sp, unsigned char inbyte) | |
862 | { | |
863 | unsigned char *buf; | |
864 | ||
865 | if (sp->rx_count != 3) { | |
866 | sp->raw_buf[sp->rx_count++] = inbyte; | |
867 | ||
868 | return; | |
869 | } | |
870 | ||
871 | buf = sp->raw_buf; | |
872 | sp->cooked_buf[sp->rx_count_cooked++] = | |
873 | buf[0] | ((buf[1] << 2) & 0xc0); | |
874 | sp->cooked_buf[sp->rx_count_cooked++] = | |
875 | (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0); | |
876 | sp->cooked_buf[sp->rx_count_cooked++] = | |
877 | (buf[2] & 0x03) | (inbyte << 2); | |
878 | sp->rx_count = 0; | |
879 | } | |
880 | ||
881 | /* identify and execute a 6pack priority command byte */ | |
882 | ||
883 | static void decode_prio_command(struct sixpack *sp, unsigned char cmd) | |
884 | { | |
885 | unsigned char channel; | |
886 | int actual; | |
887 | ||
888 | channel = cmd & SIXP_CHN_MASK; | |
889 | if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */ | |
890 | ||
891 | /* RX and DCD flags can only be set in the same prio command, | |
892 | if the DCD flag has been set without the RX flag in the previous | |
893 | prio command. If DCD has not been set before, something in the | |
894 | transmission has gone wrong. In this case, RX and DCD are | |
895 | cleared in order to prevent the decode_data routine from | |
896 | reading further data that might be corrupt. */ | |
897 | ||
898 | if (((sp->status & SIXP_DCD_MASK) == 0) && | |
899 | ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) { | |
900 | if (sp->status != 1) | |
901 | printk(KERN_DEBUG "6pack: protocol violation\n"); | |
902 | else | |
903 | sp->status = 0; | |
95f6134e | 904 | cmd &= ~SIXP_RX_DCD_MASK; |
1da177e4 LT |
905 | } |
906 | sp->status = cmd & SIXP_PRIO_DATA_MASK; | |
907 | } else { /* output watchdog char if idle */ | |
908 | if ((sp->status2 != 0) && (sp->duplex == 1)) { | |
909 | sp->led_state = 0x70; | |
f34d7a5b | 910 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 | 911 | sp->tx_enable = 1; |
f34d7a5b | 912 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); |
1da177e4 LT |
913 | sp->xleft -= actual; |
914 | sp->xhead += actual; | |
915 | sp->led_state = 0x60; | |
916 | sp->status2 = 0; | |
917 | ||
918 | } | |
919 | } | |
920 | ||
921 | /* needed to trigger the TNC watchdog */ | |
f34d7a5b | 922 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
923 | |
924 | /* if the state byte has been received, the TNC is present, | |
925 | so the resync timer can be reset. */ | |
926 | ||
927 | if (sp->tnc_state == TNC_IN_SYNC) { | |
928 | del_timer(&sp->resync_t); | |
929 | sp->resync_t.data = (unsigned long) sp; | |
930 | sp->resync_t.function = resync_tnc; | |
931 | sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT; | |
932 | add_timer(&sp->resync_t); | |
933 | } | |
934 | ||
935 | sp->status1 = cmd & SIXP_PRIO_DATA_MASK; | |
936 | } | |
937 | ||
938 | /* identify and execute a standard 6pack command byte */ | |
939 | ||
940 | static void decode_std_command(struct sixpack *sp, unsigned char cmd) | |
941 | { | |
942 | unsigned char checksum = 0, rest = 0, channel; | |
943 | short i; | |
944 | ||
945 | channel = cmd & SIXP_CHN_MASK; | |
946 | switch (cmd & SIXP_CMD_MASK) { /* normal command */ | |
947 | case SIXP_SEOF: | |
948 | if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) { | |
949 | if ((sp->status & SIXP_RX_DCD_MASK) == | |
950 | SIXP_RX_DCD_MASK) { | |
951 | sp->led_state = 0x68; | |
f34d7a5b | 952 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
953 | } |
954 | } else { | |
955 | sp->led_state = 0x60; | |
956 | /* fill trailing bytes with zeroes */ | |
f34d7a5b | 957 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
1da177e4 LT |
958 | rest = sp->rx_count; |
959 | if (rest != 0) | |
960 | for (i = rest; i <= 3; i++) | |
961 | decode_data(sp, 0); | |
962 | if (rest == 2) | |
963 | sp->rx_count_cooked -= 2; | |
964 | else if (rest == 3) | |
965 | sp->rx_count_cooked -= 1; | |
966 | for (i = 0; i < sp->rx_count_cooked; i++) | |
967 | checksum += sp->cooked_buf[i]; | |
968 | if (checksum != SIXP_CHKSUM) { | |
969 | printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum); | |
970 | } else { | |
971 | sp->rcount = sp->rx_count_cooked-2; | |
972 | sp_bump(sp, 0); | |
973 | } | |
974 | sp->rx_count_cooked = 0; | |
975 | } | |
976 | break; | |
977 | case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n"); | |
978 | break; | |
979 | case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n"); | |
980 | break; | |
981 | case SIXP_RX_BUF_OVL: | |
982 | printk(KERN_DEBUG "6pack: RX buffer overflow\n"); | |
983 | } | |
984 | } | |
985 | ||
986 | /* decode a 6pack packet */ | |
987 | ||
988 | static void | |
989 | sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count) | |
990 | { | |
991 | unsigned char inbyte; | |
992 | int count1; | |
993 | ||
994 | for (count1 = 0; count1 < count; count1++) { | |
995 | inbyte = pre_rbuff[count1]; | |
996 | if (inbyte == SIXP_FOUND_TNC) { | |
997 | tnc_set_sync_state(sp, TNC_IN_SYNC); | |
998 | del_timer(&sp->resync_t); | |
999 | } | |
1000 | if ((inbyte & SIXP_PRIO_CMD_MASK) != 0) | |
1001 | decode_prio_command(sp, inbyte); | |
1002 | else if ((inbyte & SIXP_STD_CMD_MASK) != 0) | |
1003 | decode_std_command(sp, inbyte); | |
1004 | else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK) | |
1005 | decode_data(sp, inbyte); | |
1006 | } | |
1007 | } | |
1008 | ||
1009 | MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>"); | |
1010 | MODULE_DESCRIPTION("6pack driver for AX.25"); | |
1011 | MODULE_LICENSE("GPL"); | |
1012 | MODULE_ALIAS_LDISC(N_6PACK); | |
1013 | ||
1014 | module_init(sixpack_init_driver); | |
1015 | module_exit(sixpack_exit_driver); |