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NET: Fix locking issues in PPP, 6pack, mkiss and strip line disciplines.
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / net / hamradio / 6pack.c
blob913a5640659428255cfaec0d308996bc824257ca
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@iehk.rwth-aachen.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 int sp_xmit(struct sk_buff *skb, struct net_device *dev)
246 {
247 struct sixpack *sp = netdev_priv(dev);
248
249 spin_lock_bh(&sp->lock);
250 /* We were not busy, so we are now... :-) */
251 netif_stop_queue(dev);
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 0;
259 }
260
261 static int sp_open_dev(struct net_device *dev)
262 {
263 struct sixpack *sp = netdev_priv(dev);
264
265 if (sp->tty == NULL)
266 return -ENODEV;
267 return 0;
268 }
269
270 /* Close the low-level part of the 6pack channel. */
271 static int sp_close(struct net_device *dev)
272 {
273 struct sixpack *sp = netdev_priv(dev);
274
275 spin_lock_bh(&sp->lock);
276 if (sp->tty) {
277 /* TTY discipline is running. */
278 clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
279 }
280 netif_stop_queue(dev);
281 spin_unlock_bh(&sp->lock);
282
283 return 0;
284 }
285
286 /* Return the frame type ID */
287 static int sp_header(struct sk_buff *skb, struct net_device *dev,
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 unsigned long flags;
402 struct sixpack *sp;
403
404 read_lock_irqsave(&disc_data_lock, flags);
405 sp = tty->disc_data;
406 if (sp)
407 atomic_inc(&sp->refcnt);
408 read_unlock_irqrestore(&disc_data_lock, flags);
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 init_MUTEX_LOCKED(&sp->dead_sem);
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 unsigned long flags;
693 struct sixpack *sp;
694
695 write_lock_irqsave(&disc_data_lock, flags);
696 sp = tty->disc_data;
697 tty->disc_data = NULL;
698 write_unlock_irqrestore(&disc_data_lock, flags);
699 if (!sp)
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);
724 struct net_device *dev;
725 unsigned int tmp, err;
726
727 if (!sp)
728 return -ENXIO;
729 dev = sp->dev;
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)) {
761 err = -EFAULT;
762 break;
763 }
764
765 netif_tx_lock_bh(dev);
766 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN);
767 netif_tx_unlock_bh(dev);
768
769 err = 0;
770 break;
771 }
772
773 default:
774 err = tty_mode_ioctl(tty, file, cmd, arg);
775 }
776
777 sp_put(sp);
778
779 return err;
780 }
781
782 static struct tty_ldisc_ops sp_ldisc = {
783 .owner = THIS_MODULE,
784 .magic = TTY_LDISC_MAGIC,
785 .name = "6pack",
786 .open = sixpack_open,
787 .close = sixpack_close,
788 .ioctl = sixpack_ioctl,
789 .receive_buf = sixpack_receive_buf,
790 .write_wakeup = sixpack_write_wakeup,
791 };
792
793 /* Initialize 6pack control device -- register 6pack line discipline */
794
795 static const char msg_banner[] __initdata = KERN_INFO \
796 "AX.25: 6pack driver, " SIXPACK_VERSION "\n";
797 static const char msg_regfail[] __initdata = KERN_ERR \
798 "6pack: can't register line discipline (err = %d)\n";
799
800 static int __init sixpack_init_driver(void)
801 {
802 int status;
803
804 printk(msg_banner);
805
806 /* Register the provided line protocol discipline */
807 if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0)
808 printk(msg_regfail, status);
809
810 return status;
811 }
812
813 static const char msg_unregfail[] __exitdata = KERN_ERR \
814 "6pack: can't unregister line discipline (err = %d)\n";
815
816 static void __exit sixpack_exit_driver(void)
817 {
818 int ret;
819
820 if ((ret = tty_unregister_ldisc(N_6PACK)))
821 printk(msg_unregfail, ret);
822 }
823
824 /* encode an AX.25 packet into 6pack */
825
826 static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw,
827 int length, unsigned char tx_delay)
828 {
829 int count = 0;
830 unsigned char checksum = 0, buf[400];
831 int raw_count = 0;
832
833 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK;
834 tx_buf_raw[raw_count++] = SIXP_SEOF;
835
836 buf[0] = tx_delay;
837 for (count = 1; count < length; count++)
838 buf[count] = tx_buf[count];
839
840 for (count = 0; count < length; count++)
841 checksum += buf[count];
842 buf[length] = (unsigned char) 0xff - checksum;
843
844 for (count = 0; count <= length; count++) {
845 if ((count % 3) == 0) {
846 tx_buf_raw[raw_count++] = (buf[count] & 0x3f);
847 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30);
848 } else if ((count % 3) == 1) {
849 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f);
850 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c);
851 } else {
852 tx_buf_raw[raw_count++] |= (buf[count] & 0x03);
853 tx_buf_raw[raw_count++] = (buf[count] >> 2);
854 }
855 }
856 if ((length % 3) != 2)
857 raw_count++;
858 tx_buf_raw[raw_count++] = SIXP_SEOF;
859 return raw_count;
860 }
861
862 /* decode 4 sixpack-encoded bytes into 3 data bytes */
863
864 static void decode_data(struct sixpack *sp, unsigned char inbyte)
865 {
866 unsigned char *buf;
867
868 if (sp->rx_count != 3) {
869 sp->raw_buf[sp->rx_count++] = inbyte;
870
871 return;
872 }
873
874 buf = sp->raw_buf;
875 sp->cooked_buf[sp->rx_count_cooked++] =
876 buf[0] | ((buf[1] << 2) & 0xc0);
877 sp->cooked_buf[sp->rx_count_cooked++] =
878 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0);
879 sp->cooked_buf[sp->rx_count_cooked++] =
880 (buf[2] & 0x03) | (inbyte << 2);
881 sp->rx_count = 0;
882 }
883
884 /* identify and execute a 6pack priority command byte */
885
886 static void decode_prio_command(struct sixpack *sp, unsigned char cmd)
887 {
888 unsigned char channel;
889 int actual;
890
891 channel = cmd & SIXP_CHN_MASK;
892 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */
893
894 /* RX and DCD flags can only be set in the same prio command,
895 if the DCD flag has been set without the RX flag in the previous
896 prio command. If DCD has not been set before, something in the
897 transmission has gone wrong. In this case, RX and DCD are
898 cleared in order to prevent the decode_data routine from
899 reading further data that might be corrupt. */
900
901 if (((sp->status & SIXP_DCD_MASK) == 0) &&
902 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) {
903 if (sp->status != 1)
904 printk(KERN_DEBUG "6pack: protocol violation\n");
905 else
906 sp->status = 0;
907 cmd &= ~SIXP_RX_DCD_MASK;
908 }
909 sp->status = cmd & SIXP_PRIO_DATA_MASK;
910 } else { /* output watchdog char if idle */
911 if ((sp->status2 != 0) && (sp->duplex == 1)) {
912 sp->led_state = 0x70;
913 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
914 sp->tx_enable = 1;
915 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
916 sp->xleft -= actual;
917 sp->xhead += actual;
918 sp->led_state = 0x60;
919 sp->status2 = 0;
920
921 }
922 }
923
924 /* needed to trigger the TNC watchdog */
925 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
926
927 /* if the state byte has been received, the TNC is present,
928 so the resync timer can be reset. */
929
930 if (sp->tnc_state == TNC_IN_SYNC) {
931 del_timer(&sp->resync_t);
932 sp->resync_t.data = (unsigned long) sp;
933 sp->resync_t.function = resync_tnc;
934 sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT;
935 add_timer(&sp->resync_t);
936 }
937
938 sp->status1 = cmd & SIXP_PRIO_DATA_MASK;
939 }
940
941 /* identify and execute a standard 6pack command byte */
942
943 static void decode_std_command(struct sixpack *sp, unsigned char cmd)
944 {
945 unsigned char checksum = 0, rest = 0, channel;
946 short i;
947
948 channel = cmd & SIXP_CHN_MASK;
949 switch (cmd & SIXP_CMD_MASK) { /* normal command */
950 case SIXP_SEOF:
951 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) {
952 if ((sp->status & SIXP_RX_DCD_MASK) ==
953 SIXP_RX_DCD_MASK) {
954 sp->led_state = 0x68;
955 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
956 }
957 } else {
958 sp->led_state = 0x60;
959 /* fill trailing bytes with zeroes */
960 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
961 rest = sp->rx_count;
962 if (rest != 0)
963 for (i = rest; i <= 3; i++)
964 decode_data(sp, 0);
965 if (rest == 2)
966 sp->rx_count_cooked -= 2;
967 else if (rest == 3)
968 sp->rx_count_cooked -= 1;
969 for (i = 0; i < sp->rx_count_cooked; i++)
970 checksum += sp->cooked_buf[i];
971 if (checksum != SIXP_CHKSUM) {
972 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum);
973 } else {
974 sp->rcount = sp->rx_count_cooked-2;
975 sp_bump(sp, 0);
976 }
977 sp->rx_count_cooked = 0;
978 }
979 break;
980 case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n");
981 break;
982 case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n");
983 break;
984 case SIXP_RX_BUF_OVL:
985 printk(KERN_DEBUG "6pack: RX buffer overflow\n");
986 }
987 }
988
989 /* decode a 6pack packet */
990
991 static void
992 sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count)
993 {
994 unsigned char inbyte;
995 int count1;
996
997 for (count1 = 0; count1 < count; count1++) {
998 inbyte = pre_rbuff[count1];
999 if (inbyte == SIXP_FOUND_TNC) {
1000 tnc_set_sync_state(sp, TNC_IN_SYNC);
1001 del_timer(&sp->resync_t);
1002 }
1003 if ((inbyte & SIXP_PRIO_CMD_MASK) != 0)
1004 decode_prio_command(sp, inbyte);
1005 else if ((inbyte & SIXP_STD_CMD_MASK) != 0)
1006 decode_std_command(sp, inbyte);
1007 else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)
1008 decode_data(sp, inbyte);
1009 }
1010 }
1011
1012 MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>");
1013 MODULE_DESCRIPTION("6pack driver for AX.25");
1014 MODULE_LICENSE("GPL");
1015 MODULE_ALIAS_LDISC(N_6PACK);
1016
1017 module_init(sixpack_init_driver);
1018 module_exit(sixpack_exit_driver);
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree