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jbd2: Annotate transaction start also for jbd2_journal_restart()
[linux/fpc-iii.git] / drivers / net / hamradio / 6pack.c
blobfb588301a05dd4ad058f8230299e8e66248a6b95
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 *
6 * Authors: Andreas Könsgen <ajk@comnets.uni-bremen.de>
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
15 #include <linux/module.h>
16 #include <asm/system.h>
17 #include <asm/uaccess.h>
18 #include <linux/bitops.h>
19 #include <linux/string.h>
20 #include <linux/mm.h>
21 #include <linux/interrupt.h>
22 #include <linux/in.h>
23 #include <linux/tty.h>
24 #include <linux/errno.h>
25 #include <linux/netdevice.h>
26 #include <linux/timer.h>
27 #include <net/ax25.h>
28 #include <linux/etherdevice.h>
29 #include <linux/skbuff.h>
30 #include <linux/rtnetlink.h>
31 #include <linux/spinlock.h>
32 #include <linux/if_arp.h>
33 #include <linux/init.h>
34 #include <linux/ip.h>
35 #include <linux/tcp.h>
36 #include <linux/semaphore.h>
37 #include <asm/atomic.h>
38
39 #define SIXPACK_VERSION "Revision: 0.3.0"
40
41 /* sixpack priority commands */
42 #define SIXP_SEOF 0x40 /* start and end of a 6pack frame */
43 #define SIXP_TX_URUN 0x48 /* transmit overrun */
44 #define SIXP_RX_ORUN 0x50 /* receive overrun */
45 #define SIXP_RX_BUF_OVL 0x58 /* receive buffer overflow */
46
47 #define SIXP_CHKSUM 0xFF /* valid checksum of a 6pack frame */
48
49 /* masks to get certain bits out of the status bytes sent by the TNC */
50
51 #define SIXP_CMD_MASK 0xC0
52 #define SIXP_CHN_MASK 0x07
53 #define SIXP_PRIO_CMD_MASK 0x80
54 #define SIXP_STD_CMD_MASK 0x40
55 #define SIXP_PRIO_DATA_MASK 0x38
56 #define SIXP_TX_MASK 0x20
57 #define SIXP_RX_MASK 0x10
58 #define SIXP_RX_DCD_MASK 0x18
59 #define SIXP_LEDS_ON 0x78
60 #define SIXP_LEDS_OFF 0x60
61 #define SIXP_CON 0x08
62 #define SIXP_STA 0x10
63
64 #define SIXP_FOUND_TNC 0xe9
65 #define SIXP_CON_ON 0x68
66 #define SIXP_DCD_MASK 0x08
67 #define SIXP_DAMA_OFF 0
68
69 /* default level 2 parameters */
70 #define SIXP_TXDELAY (HZ/4) /* in 1 s */
71 #define SIXP_PERSIST 50 /* in 256ths */
72 #define SIXP_SLOTTIME (HZ/10) /* in 1 s */
73 #define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */
74 #define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */
75
76 /* 6pack configuration. */
77 #define SIXP_NRUNIT 31 /* MAX number of 6pack channels */
78 #define SIXP_MTU 256 /* Default MTU */
79
80 enum sixpack_flags {
81 SIXPF_ERROR, /* Parity, etc. error */
82 };
83
84 struct sixpack {
85 /* Various fields. */
86 struct tty_struct *tty; /* ptr to TTY structure */
87 struct net_device *dev; /* easy for intr handling */
88
89 /* These are pointers to the malloc()ed frame buffers. */
90 unsigned char *rbuff; /* receiver buffer */
91 int rcount; /* received chars counter */
92 unsigned char *xbuff; /* transmitter buffer */
93 unsigned char *xhead; /* next byte to XMIT */
94 int xleft; /* bytes left in XMIT queue */
95
96 unsigned char raw_buf[4];
97 unsigned char cooked_buf[400];
98
99 unsigned int rx_count;
100 unsigned int rx_count_cooked;
101
102 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
129 static void sixpack_decode(struct sixpack *, unsigned char[], int);
130 static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char);
131
132 /*
133 * Perform the persistence/slottime algorithm for CSMA access. If the
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;
141 int actual, when = sp->slottime;
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;
148 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
149 sp->tx_enable = 1;
150 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
151 sp->xleft -= actual;
152 sp->xhead += actual;
153 sp->led_state = 0x60;
154 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
155 sp->status2 = 0;
156 } else
157 mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100);
158 }
159
160 /* ----> 6pack timer interrupt handler and friends. <---- */
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;
220 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
221 sp->tx_enable = 1;
222 actual = sp->tty->ops->write(sp->tty, sp->xbuff, count);
223 sp->xleft = count - actual;
224 sp->xhead = sp->xbuff + actual;
225 sp->led_state = 0x60;
226 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
227 } else {
228 sp->xleft = count;
229 sp->xhead = sp->xbuff;
230 sp->status2 = count;
231 sp_xmit_on_air((unsigned long)sp);
232 }
233
234 return;
235
236 out_drop:
237 sp->dev->stats.tx_dropped++;
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 netdev_tx_t 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);
252 dev->stats.tx_bytes += skb->len;
253 sp_encaps(sp, skb->data, skb->len);
254 spin_unlock_bh(&sp->lock);
255
256 dev_kfree_skb(skb);
257
258 return NETDEV_TX_OK;
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,
288 unsigned short type, const void *daddr,
289 const void *saddr, unsigned len)
290 {
291 #ifdef CONFIG_INET
292 if (type != ETH_P_AX25)
293 return ax25_hard_header(skb, dev, type, daddr, saddr, len);
294 #endif
295 return 0;
296 }
297
298 static int sp_set_mac_address(struct net_device *dev, void *addr)
299 {
300 struct sockaddr_ax25 *sa = addr;
301
302 netif_tx_lock_bh(dev);
303 netif_addr_lock(dev);
304 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
305 netif_addr_unlock(dev);
306 netif_tx_unlock_bh(dev);
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
320 static const struct header_ops sp_header_ops = {
321 .create = sp_header,
322 .rebuild = sp_rebuild_header,
323 };
324
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
332 static void sp_setup(struct net_device *dev)
333 {
334 /* Finish setting up the DEVICE info. */
335 dev->netdev_ops = &sp_netdev_ops;
336 dev->destructor = free_netdev;
337 dev->mtu = SIXP_MTU;
338 dev->hard_header_len = AX25_MAX_HEADER_LEN;
339 dev->header_ops = &sp_header_ops;
340
341 dev->addr_len = AX25_ADDR_LEN;
342 dev->type = ARPHRD_AX25;
343 dev->tx_queue_len = 10;
344
345 /* Only activated in AX.25 mode */
346 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
347 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
348
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
367 sp->dev->stats.rx_bytes += count;
368
369 if ((skb = dev_alloc_skb(count)) == NULL)
370 goto out_mem;
371
372 ptr = skb_put(skb, count);
373 *ptr++ = cmd; /* KISS command */
374
375 memcpy(ptr, sp->cooked_buf + 1, count);
376 skb->protocol = ax25_type_trans(skb, sp->dev);
377 netif_rx(skb);
378 sp->dev->stats.rx_packets++;
379
380 return;
381
382 out_mem:
383 sp->dev->stats.rx_dropped++;
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
403 read_lock(&disc_data_lock);
404 sp = tty->disc_data;
405 if (sp)
406 atomic_inc(&sp->refcnt);
407 read_unlock(&disc_data_lock);
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 */
432 sp->dev->stats.tx_packets++;
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) {
440 actual = tty->ops->write(tty, sp->xhead, sp->xleft);
441 sp->xleft -= actual;
442 sp->xhead += actual;
443 }
444
445 out:
446 sp_put(sp);
447 }
448
449 /* ----------------------------------------------------------------------- */
450
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))
480 sp->dev->stats.rx_errors++;
481 continue;
482 }
483 }
484 sixpack_decode(sp, buf, count1);
485
486 sp_put(sp);
487 tty_unthrottle(tty);
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;
548 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
549 sp->tty->ops->write(sp->tty, &resync_cmd, 1);
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
567 sp->tty->ops->write(sp->tty, &inbyte, 1);
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;
595 if (tty->ops->write == NULL)
596 return -EOPNOTSUPP;
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);
652 sp->tx_t.function = sp_xmit_on_air;
653 sp->tx_t.data = (unsigned long) sp;
654
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;
661 tty->receive_room = 65536;
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
693 write_lock(&disc_data_lock);
694 sp = tty->disc_data;
695 tty->disc_data = NULL;
696 write_unlock(&disc_data_lock);
697 if (!sp)
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);
722 struct net_device *dev;
723 unsigned int tmp, err;
724
725 if (!sp)
726 return -ENXIO;
727 dev = sp->dev;
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)) {
759 err = -EFAULT;
760 break;
761 }
762
763 netif_tx_lock_bh(dev);
764 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN);
765 netif_tx_unlock_bh(dev);
766
767 err = 0;
768 break;
769 }
770
771 default:
772 err = tty_mode_ioctl(tty, file, cmd, arg);
773 }
774
775 sp_put(sp);
776
777 return err;
778 }
779
780 static struct tty_ldisc_ops sp_ldisc = {
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,
788 .write_wakeup = sixpack_write_wakeup,
789 };
790
791 /* Initialize 6pack control device -- register 6pack line discipline */
792
793 static const char msg_banner[] __initdata = KERN_INFO \
794 "AX.25: 6pack driver, " SIXPACK_VERSION "\n";
795 static const char msg_regfail[] __initdata = KERN_ERR \
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
818 if ((ret = tty_unregister_ldisc(N_6PACK)))
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;
905 cmd &= ~SIXP_RX_DCD_MASK;
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;
911 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
912 sp->tx_enable = 1;
913 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
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 */
923 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
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;
953 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
954 }
955 } else {
956 sp->led_state = 0x60;
957 /* fill trailing bytes with zeroes */
958 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
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);
Linux with added FPC-III support