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usblp: do not set TASK_INTERRUPTIBLE before lock
[linux/fpc-iii.git] / drivers / net / hamradio / 6pack.c
blob1450e33fc250e7e0bb4edf73aa6abc06df1a1855
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/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>
26 #include <linux/slab.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 <linux/compat.h>
38 #include <linux/atomic.h>
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
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
130 static void sixpack_decode(struct sixpack *, unsigned char[], int);
131 static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char);
132
133 /*
134 * Perform the persistence/slottime algorithm for CSMA access. If the
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;
142 int actual, when = sp->slottime;
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;
149 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
150 sp->tx_enable = 1;
151 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
152 sp->xleft -= actual;
153 sp->xhead += actual;
154 sp->led_state = 0x60;
155 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
156 sp->status2 = 0;
157 } else
158 mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100);
159 }
160
161 /* ----> 6pack timer interrupt handler and friends. <---- */
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;
221 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
222 sp->tx_enable = 1;
223 actual = sp->tty->ops->write(sp->tty, sp->xbuff, count);
224 sp->xleft = count - actual;
225 sp->xhead = sp->xbuff + actual;
226 sp->led_state = 0x60;
227 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
228 } else {
229 sp->xleft = count;
230 sp->xhead = sp->xbuff;
231 sp->status2 = count;
232 sp_xmit_on_air((unsigned long)sp);
233 }
234
235 return;
236
237 out_drop:
238 sp->dev->stats.tx_dropped++;
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
246 static netdev_tx_t sp_xmit(struct sk_buff *skb, struct net_device *dev)
247 {
248 struct sixpack *sp = netdev_priv(dev);
249
250 spin_lock_bh(&sp->lock);
251 /* We were not busy, so we are now... :-) */
252 netif_stop_queue(dev);
253 dev->stats.tx_bytes += skb->len;
254 sp_encaps(sp, skb->data, skb->len);
255 spin_unlock_bh(&sp->lock);
256
257 dev_kfree_skb(skb);
258
259 return NETDEV_TX_OK;
260 }
261
262 static int sp_open_dev(struct net_device *dev)
263 {
264 struct sixpack *sp = netdev_priv(dev);
265
266 if (sp->tty == NULL)
267 return -ENODEV;
268 return 0;
269 }
270
271 /* Close the low-level part of the 6pack channel. */
272 static int sp_close(struct net_device *dev)
273 {
274 struct sixpack *sp = netdev_priv(dev);
275
276 spin_lock_bh(&sp->lock);
277 if (sp->tty) {
278 /* TTY discipline is running. */
279 clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
280 }
281 netif_stop_queue(dev);
282 spin_unlock_bh(&sp->lock);
283
284 return 0;
285 }
286
287 /* Return the frame type ID */
288 static int sp_header(struct sk_buff *skb, struct net_device *dev,
289 unsigned short type, const void *daddr,
290 const void *saddr, unsigned len)
291 {
292 #ifdef CONFIG_INET
293 if (type != ETH_P_AX25)
294 return ax25_hard_header(skb, dev, type, daddr, saddr, len);
295 #endif
296 return 0;
297 }
298
299 static int sp_set_mac_address(struct net_device *dev, void *addr)
300 {
301 struct sockaddr_ax25 *sa = addr;
302
303 netif_tx_lock_bh(dev);
304 netif_addr_lock(dev);
305 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
306 netif_addr_unlock(dev);
307 netif_tx_unlock_bh(dev);
308
309 return 0;
310 }
311
312 static int sp_rebuild_header(struct sk_buff *skb)
313 {
314 #ifdef CONFIG_INET
315 return ax25_rebuild_header(skb);
316 #else
317 return 0;
318 #endif
319 }
320
321 static const struct header_ops sp_header_ops = {
322 .create = sp_header,
323 .rebuild = sp_rebuild_header,
324 };
325
326 static const struct net_device_ops sp_netdev_ops = {
327 .ndo_open = sp_open_dev,
328 .ndo_stop = sp_close,
329 .ndo_start_xmit = sp_xmit,
330 .ndo_set_mac_address = sp_set_mac_address,
331 };
332
333 static void sp_setup(struct net_device *dev)
334 {
335 /* Finish setting up the DEVICE info. */
336 dev->netdev_ops = &sp_netdev_ops;
337 dev->destructor = free_netdev;
338 dev->mtu = SIXP_MTU;
339 dev->hard_header_len = AX25_MAX_HEADER_LEN;
340 dev->header_ops = &sp_header_ops;
341
342 dev->addr_len = AX25_ADDR_LEN;
343 dev->type = ARPHRD_AX25;
344 dev->tx_queue_len = 10;
345
346 /* Only activated in AX.25 mode */
347 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
348 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
349
350 dev->flags = 0;
351 }
352
353 /* Send one completely decapsulated IP datagram to the IP layer. */
354
355 /*
356 * This is the routine that sends the received data to the kernel AX.25.
357 * 'cmd' is the KISS command. For AX.25 data, it is zero.
358 */
359
360 static void sp_bump(struct sixpack *sp, char cmd)
361 {
362 struct sk_buff *skb;
363 int count;
364 unsigned char *ptr;
365
366 count = sp->rcount + 1;
367
368 sp->dev->stats.rx_bytes += count;
369
370 if ((skb = dev_alloc_skb(count)) == NULL)
371 goto out_mem;
372
373 ptr = skb_put(skb, count);
374 *ptr++ = cmd; /* KISS command */
375
376 memcpy(ptr, sp->cooked_buf + 1, count);
377 skb->protocol = ax25_type_trans(skb, sp->dev);
378 netif_rx(skb);
379 sp->dev->stats.rx_packets++;
380
381 return;
382
383 out_mem:
384 sp->dev->stats.rx_dropped++;
385 }
386
387
388 /* ----------------------------------------------------------------------- */
389
390 /*
391 * We have a potential race on dereferencing tty->disc_data, because the tty
392 * layer provides no locking at all - thus one cpu could be running
393 * sixpack_receive_buf while another calls sixpack_close, which zeroes
394 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
395 * best way to fix this is to use a rwlock in the tty struct, but for now we
396 * use a single global rwlock for all ttys in ppp line discipline.
397 */
398 static DEFINE_RWLOCK(disc_data_lock);
399
400 static struct sixpack *sp_get(struct tty_struct *tty)
401 {
402 struct sixpack *sp;
403
404 read_lock(&disc_data_lock);
405 sp = tty->disc_data;
406 if (sp)
407 atomic_inc(&sp->refcnt);
408 read_unlock(&disc_data_lock);
409
410 return sp;
411 }
412
413 static void sp_put(struct sixpack *sp)
414 {
415 if (atomic_dec_and_test(&sp->refcnt))
416 up(&sp->dead_sem);
417 }
418
419 /*
420 * Called by the TTY driver when there's room for more data. If we have
421 * more packets to send, we send them here.
422 */
423 static void sixpack_write_wakeup(struct tty_struct *tty)
424 {
425 struct sixpack *sp = sp_get(tty);
426 int actual;
427
428 if (!sp)
429 return;
430 if (sp->xleft <= 0) {
431 /* Now serial buffer is almost free & we can start
432 * transmission of another packet */
433 sp->dev->stats.tx_packets++;
434 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
435 sp->tx_enable = 0;
436 netif_wake_queue(sp->dev);
437 goto out;
438 }
439
440 if (sp->tx_enable) {
441 actual = tty->ops->write(tty, sp->xhead, sp->xleft);
442 sp->xleft -= actual;
443 sp->xhead += actual;
444 }
445
446 out:
447 sp_put(sp);
448 }
449
450 /* ----------------------------------------------------------------------- */
451
452 /*
453 * Handle the 'receiver data ready' interrupt.
454 * This function is called by the 'tty_io' module in the kernel when
455 * a block of 6pack data has been received, which can now be decapsulated
456 * and sent on to some IP layer for further processing.
457 */
458 static void sixpack_receive_buf(struct tty_struct *tty,
459 const unsigned char *cp, char *fp, int count)
460 {
461 struct sixpack *sp;
462 unsigned char buf[512];
463 int count1;
464
465 if (!count)
466 return;
467
468 sp = sp_get(tty);
469 if (!sp)
470 return;
471
472 memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf));
473
474 /* Read the characters out of the buffer */
475
476 count1 = count;
477 while (count) {
478 count--;
479 if (fp && *fp++) {
480 if (!test_and_set_bit(SIXPF_ERROR, &sp->flags))
481 sp->dev->stats.rx_errors++;
482 continue;
483 }
484 }
485 sixpack_decode(sp, buf, count1);
486
487 sp_put(sp);
488 tty_unthrottle(tty);
489 }
490
491 /*
492 * Try to resync the TNC. Called by the resync timer defined in
493 * decode_prio_command
494 */
495
496 #define TNC_UNINITIALIZED 0
497 #define TNC_UNSYNC_STARTUP 1
498 #define TNC_UNSYNCED 2
499 #define TNC_IN_SYNC 3
500
501 static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
502 {
503 char *msg;
504
505 switch (new_tnc_state) {
506 default: /* gcc oh piece-o-crap ... */
507 case TNC_UNSYNC_STARTUP:
508 msg = "Synchronizing with TNC";
509 break;
510 case TNC_UNSYNCED:
511 msg = "Lost synchronization with TNC\n";
512 break;
513 case TNC_IN_SYNC:
514 msg = "Found TNC";
515 break;
516 }
517
518 sp->tnc_state = new_tnc_state;
519 printk(KERN_INFO "%s: %s\n", sp->dev->name, msg);
520 }
521
522 static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
523 {
524 int old_tnc_state = sp->tnc_state;
525
526 if (old_tnc_state != new_tnc_state)
527 __tnc_set_sync_state(sp, new_tnc_state);
528 }
529
530 static void resync_tnc(unsigned long channel)
531 {
532 struct sixpack *sp = (struct sixpack *) channel;
533 static char resync_cmd = 0xe8;
534
535 /* clear any data that might have been received */
536
537 sp->rx_count = 0;
538 sp->rx_count_cooked = 0;
539
540 /* reset state machine */
541
542 sp->status = 1;
543 sp->status1 = 1;
544 sp->status2 = 0;
545
546 /* resync the TNC */
547
548 sp->led_state = 0x60;
549 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
550 sp->tty->ops->write(sp->tty, &resync_cmd, 1);
551
552
553 /* Start resync timer again -- the TNC might be still absent */
554
555 del_timer(&sp->resync_t);
556 sp->resync_t.data = (unsigned long) sp;
557 sp->resync_t.function = resync_tnc;
558 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT;
559 add_timer(&sp->resync_t);
560 }
561
562 static inline int tnc_init(struct sixpack *sp)
563 {
564 unsigned char inbyte = 0xe8;
565
566 tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP);
567
568 sp->tty->ops->write(sp->tty, &inbyte, 1);
569
570 del_timer(&sp->resync_t);
571 sp->resync_t.data = (unsigned long) sp;
572 sp->resync_t.function = resync_tnc;
573 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT;
574 add_timer(&sp->resync_t);
575
576 return 0;
577 }
578
579 /*
580 * Open the high-level part of the 6pack channel.
581 * This function is called by the TTY module when the
582 * 6pack line discipline is called for. Because we are
583 * sure the tty line exists, we only have to link it to
584 * a free 6pcack channel...
585 */
586 static int sixpack_open(struct tty_struct *tty)
587 {
588 char *rbuff = NULL, *xbuff = NULL;
589 struct net_device *dev;
590 struct sixpack *sp;
591 unsigned long len;
592 int err = 0;
593
594 if (!capable(CAP_NET_ADMIN))
595 return -EPERM;
596 if (tty->ops->write == NULL)
597 return -EOPNOTSUPP;
598
599 dev = alloc_netdev(sizeof(struct sixpack), "sp%d", sp_setup);
600 if (!dev) {
601 err = -ENOMEM;
602 goto out;
603 }
604
605 sp = netdev_priv(dev);
606 sp->dev = dev;
607
608 spin_lock_init(&sp->lock);
609 atomic_set(&sp->refcnt, 1);
610 sema_init(&sp->dead_sem, 0);
611
612 /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */
613
614 len = dev->mtu * 2;
615
616 rbuff = kmalloc(len + 4, GFP_KERNEL);
617 xbuff = kmalloc(len + 4, GFP_KERNEL);
618
619 if (rbuff == NULL || xbuff == NULL) {
620 err = -ENOBUFS;
621 goto out_free;
622 }
623
624 spin_lock_bh(&sp->lock);
625
626 sp->tty = tty;
627
628 sp->rbuff = rbuff;
629 sp->xbuff = xbuff;
630
631 sp->mtu = AX25_MTU + 73;
632 sp->buffsize = len;
633 sp->rcount = 0;
634 sp->rx_count = 0;
635 sp->rx_count_cooked = 0;
636 sp->xleft = 0;
637
638 sp->flags = 0; /* Clear ESCAPE & ERROR flags */
639
640 sp->duplex = 0;
641 sp->tx_delay = SIXP_TXDELAY;
642 sp->persistence = SIXP_PERSIST;
643 sp->slottime = SIXP_SLOTTIME;
644 sp->led_state = 0x60;
645 sp->status = 1;
646 sp->status1 = 1;
647 sp->status2 = 0;
648 sp->tx_enable = 0;
649
650 netif_start_queue(dev);
651
652 init_timer(&sp->tx_t);
653 sp->tx_t.function = sp_xmit_on_air;
654 sp->tx_t.data = (unsigned long) sp;
655
656 init_timer(&sp->resync_t);
657
658 spin_unlock_bh(&sp->lock);
659
660 /* Done. We have linked the TTY line to a channel. */
661 tty->disc_data = sp;
662 tty->receive_room = 65536;
663
664 /* Now we're ready to register. */
665 if (register_netdev(dev))
666 goto out_free;
667
668 tnc_init(sp);
669
670 return 0;
671
672 out_free:
673 kfree(xbuff);
674 kfree(rbuff);
675
676 if (dev)
677 free_netdev(dev);
678
679 out:
680 return err;
681 }
682
683
684 /*
685 * Close down a 6pack channel.
686 * This means flushing out any pending queues, and then restoring the
687 * TTY line discipline to what it was before it got hooked to 6pack
688 * (which usually is TTY again).
689 */
690 static void sixpack_close(struct tty_struct *tty)
691 {
692 struct sixpack *sp;
693
694 write_lock_bh(&disc_data_lock);
695 sp = tty->disc_data;
696 tty->disc_data = NULL;
697 write_unlock_bh(&disc_data_lock);
698 if (!sp)
699 return;
700
701 /*
702 * We have now ensured that nobody can start using ap from now on, but
703 * we have to wait for all existing users to finish.
704 */
705 if (!atomic_dec_and_test(&sp->refcnt))
706 down(&sp->dead_sem);
707
708 unregister_netdev(sp->dev);
709
710 del_timer(&sp->tx_t);
711 del_timer(&sp->resync_t);
712
713 /* Free all 6pack frame buffers. */
714 kfree(sp->rbuff);
715 kfree(sp->xbuff);
716 }
717
718 /* Perform I/O control on an active 6pack channel. */
719 static int sixpack_ioctl(struct tty_struct *tty, struct file *file,
720 unsigned int cmd, unsigned long arg)
721 {
722 struct sixpack *sp = sp_get(tty);
723 struct net_device *dev;
724 unsigned int tmp, err;
725
726 if (!sp)
727 return -ENXIO;
728 dev = sp->dev;
729
730 switch(cmd) {
731 case SIOCGIFNAME:
732 err = copy_to_user((void __user *) arg, dev->name,
733 strlen(dev->name) + 1) ? -EFAULT : 0;
734 break;
735
736 case SIOCGIFENCAP:
737 err = put_user(0, (int __user *) arg);
738 break;
739
740 case SIOCSIFENCAP:
741 if (get_user(tmp, (int __user *) arg)) {
742 err = -EFAULT;
743 break;
744 }
745
746 sp->mode = tmp;
747 dev->addr_len = AX25_ADDR_LEN;
748 dev->hard_header_len = AX25_KISS_HEADER_LEN +
749 AX25_MAX_HEADER_LEN + 3;
750 dev->type = ARPHRD_AX25;
751
752 err = 0;
753 break;
754
755 case SIOCSIFHWADDR: {
756 char addr[AX25_ADDR_LEN];
757
758 if (copy_from_user(&addr,
759 (void __user *) arg, AX25_ADDR_LEN)) {
760 err = -EFAULT;
761 break;
762 }
763
764 netif_tx_lock_bh(dev);
765 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN);
766 netif_tx_unlock_bh(dev);
767
768 err = 0;
769 break;
770 }
771
772 default:
773 err = tty_mode_ioctl(tty, file, cmd, arg);
774 }
775
776 sp_put(sp);
777
778 return err;
779 }
780
781 #ifdef CONFIG_COMPAT
782 static long sixpack_compat_ioctl(struct tty_struct * tty, struct file * file,
783 unsigned int cmd, unsigned long arg)
784 {
785 switch (cmd) {
786 case SIOCGIFNAME:
787 case SIOCGIFENCAP:
788 case SIOCSIFENCAP:
789 case SIOCSIFHWADDR:
790 return sixpack_ioctl(tty, file, cmd,
791 (unsigned long)compat_ptr(arg));
792 }
793
794 return -ENOIOCTLCMD;
795 }
796 #endif
797
798 static struct tty_ldisc_ops sp_ldisc = {
799 .owner = THIS_MODULE,
800 .magic = TTY_LDISC_MAGIC,
801 .name = "6pack",
802 .open = sixpack_open,
803 .close = sixpack_close,
804 .ioctl = sixpack_ioctl,
805 #ifdef CONFIG_COMPAT
806 .compat_ioctl = sixpack_compat_ioctl,
807 #endif
808 .receive_buf = sixpack_receive_buf,
809 .write_wakeup = sixpack_write_wakeup,
810 };
811
812 /* Initialize 6pack control device -- register 6pack line discipline */
813
814 static const char msg_banner[] __initconst = KERN_INFO \
815 "AX.25: 6pack driver, " SIXPACK_VERSION "\n";
816 static const char msg_regfail[] __initconst = KERN_ERR \
817 "6pack: can't register line discipline (err = %d)\n";
818
819 static int __init sixpack_init_driver(void)
820 {
821 int status;
822
823 printk(msg_banner);
824
825 /* Register the provided line protocol discipline */
826 if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0)
827 printk(msg_regfail, status);
828
829 return status;
830 }
831
832 static const char msg_unregfail[] = KERN_ERR \
833 "6pack: can't unregister line discipline (err = %d)\n";
834
835 static void __exit sixpack_exit_driver(void)
836 {
837 int ret;
838
839 if ((ret = tty_unregister_ldisc(N_6PACK)))
840 printk(msg_unregfail, ret);
841 }
842
843 /* encode an AX.25 packet into 6pack */
844
845 static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw,
846 int length, unsigned char tx_delay)
847 {
848 int count = 0;
849 unsigned char checksum = 0, buf[400];
850 int raw_count = 0;
851
852 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK;
853 tx_buf_raw[raw_count++] = SIXP_SEOF;
854
855 buf[0] = tx_delay;
856 for (count = 1; count < length; count++)
857 buf[count] = tx_buf[count];
858
859 for (count = 0; count < length; count++)
860 checksum += buf[count];
861 buf[length] = (unsigned char) 0xff - checksum;
862
863 for (count = 0; count <= length; count++) {
864 if ((count % 3) == 0) {
865 tx_buf_raw[raw_count++] = (buf[count] & 0x3f);
866 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30);
867 } else if ((count % 3) == 1) {
868 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f);
869 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c);
870 } else {
871 tx_buf_raw[raw_count++] |= (buf[count] & 0x03);
872 tx_buf_raw[raw_count++] = (buf[count] >> 2);
873 }
874 }
875 if ((length % 3) != 2)
876 raw_count++;
877 tx_buf_raw[raw_count++] = SIXP_SEOF;
878 return raw_count;
879 }
880
881 /* decode 4 sixpack-encoded bytes into 3 data bytes */
882
883 static void decode_data(struct sixpack *sp, unsigned char inbyte)
884 {
885 unsigned char *buf;
886
887 if (sp->rx_count != 3) {
888 sp->raw_buf[sp->rx_count++] = inbyte;
889
890 return;
891 }
892
893 buf = sp->raw_buf;
894 sp->cooked_buf[sp->rx_count_cooked++] =
895 buf[0] | ((buf[1] << 2) & 0xc0);
896 sp->cooked_buf[sp->rx_count_cooked++] =
897 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0);
898 sp->cooked_buf[sp->rx_count_cooked++] =
899 (buf[2] & 0x03) | (inbyte << 2);
900 sp->rx_count = 0;
901 }
902
903 /* identify and execute a 6pack priority command byte */
904
905 static void decode_prio_command(struct sixpack *sp, unsigned char cmd)
906 {
907 unsigned char channel;
908 int actual;
909
910 channel = cmd & SIXP_CHN_MASK;
911 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */
912
913 /* RX and DCD flags can only be set in the same prio command,
914 if the DCD flag has been set without the RX flag in the previous
915 prio command. If DCD has not been set before, something in the
916 transmission has gone wrong. In this case, RX and DCD are
917 cleared in order to prevent the decode_data routine from
918 reading further data that might be corrupt. */
919
920 if (((sp->status & SIXP_DCD_MASK) == 0) &&
921 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) {
922 if (sp->status != 1)
923 printk(KERN_DEBUG "6pack: protocol violation\n");
924 else
925 sp->status = 0;
926 cmd &= ~SIXP_RX_DCD_MASK;
927 }
928 sp->status = cmd & SIXP_PRIO_DATA_MASK;
929 } else { /* output watchdog char if idle */
930 if ((sp->status2 != 0) && (sp->duplex == 1)) {
931 sp->led_state = 0x70;
932 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
933 sp->tx_enable = 1;
934 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
935 sp->xleft -= actual;
936 sp->xhead += actual;
937 sp->led_state = 0x60;
938 sp->status2 = 0;
939
940 }
941 }
942
943 /* needed to trigger the TNC watchdog */
944 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
945
946 /* if the state byte has been received, the TNC is present,
947 so the resync timer can be reset. */
948
949 if (sp->tnc_state == TNC_IN_SYNC) {
950 del_timer(&sp->resync_t);
951 sp->resync_t.data = (unsigned long) sp;
952 sp->resync_t.function = resync_tnc;
953 sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT;
954 add_timer(&sp->resync_t);
955 }
956
957 sp->status1 = cmd & SIXP_PRIO_DATA_MASK;
958 }
959
960 /* identify and execute a standard 6pack command byte */
961
962 static void decode_std_command(struct sixpack *sp, unsigned char cmd)
963 {
964 unsigned char checksum = 0, rest = 0, channel;
965 short i;
966
967 channel = cmd & SIXP_CHN_MASK;
968 switch (cmd & SIXP_CMD_MASK) { /* normal command */
969 case SIXP_SEOF:
970 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) {
971 if ((sp->status & SIXP_RX_DCD_MASK) ==
972 SIXP_RX_DCD_MASK) {
973 sp->led_state = 0x68;
974 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
975 }
976 } else {
977 sp->led_state = 0x60;
978 /* fill trailing bytes with zeroes */
979 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
980 rest = sp->rx_count;
981 if (rest != 0)
982 for (i = rest; i <= 3; i++)
983 decode_data(sp, 0);
984 if (rest == 2)
985 sp->rx_count_cooked -= 2;
986 else if (rest == 3)
987 sp->rx_count_cooked -= 1;
988 for (i = 0; i < sp->rx_count_cooked; i++)
989 checksum += sp->cooked_buf[i];
990 if (checksum != SIXP_CHKSUM) {
991 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum);
992 } else {
993 sp->rcount = sp->rx_count_cooked-2;
994 sp_bump(sp, 0);
995 }
996 sp->rx_count_cooked = 0;
997 }
998 break;
999 case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n");
1000 break;
1001 case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n");
1002 break;
1003 case SIXP_RX_BUF_OVL:
1004 printk(KERN_DEBUG "6pack: RX buffer overflow\n");
1005 }
1006 }
1007
1008 /* decode a 6pack packet */
1009
1010 static void
1011 sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count)
1012 {
1013 unsigned char inbyte;
1014 int count1;
1015
1016 for (count1 = 0; count1 < count; count1++) {
1017 inbyte = pre_rbuff[count1];
1018 if (inbyte == SIXP_FOUND_TNC) {
1019 tnc_set_sync_state(sp, TNC_IN_SYNC);
1020 del_timer(&sp->resync_t);
1021 }
1022 if ((inbyte & SIXP_PRIO_CMD_MASK) != 0)
1023 decode_prio_command(sp, inbyte);
1024 else if ((inbyte & SIXP_STD_CMD_MASK) != 0)
1025 decode_std_command(sp, inbyte);
1026 else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)
1027 decode_data(sp, inbyte);
1028 }
1029 }
1030
1031 MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>");
1032 MODULE_DESCRIPTION("6pack driver for AX.25");
1033 MODULE_LICENSE("GPL");
1034 MODULE_ALIAS_LDISC(N_6PACK);
1035
1036 module_init(sixpack_init_driver);
1037 module_exit(sixpack_exit_driver);
Linux with added FPC-III support