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Merge branch 'r8169-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/romieu...
[deliverable/linux.git] / drivers / net / hamradio / 6pack.c
CommitLineData
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 *
96de0e25 6 * Authors: Andreas Könsgen <ajk@iehk.rwth-aachen.de>
1da177e4
LT		 7 * Ralf Baechle DL5RB <ralf@linux-mips.org>
8 *
9 * Quite a lot of stuff "stolen" by Joerg Reuter from slip.c, written by
10 *
11 * Laurence Culhane, <loz@holmes.demon.co.uk>
12 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
13 */
14
1da177e4
LT		 15#include <linux/module.h>
16#include <asm/system.h>
17#include <asm/uaccess.h>
18#include <linux/bitops.h>
19#include <linux/string.h>
20#include <linux/mm.h>
21#include <linux/interrupt.h>
22#include <linux/in.h>
23#include <linux/tty.h>
24#include <linux/errno.h>
25#include <linux/netdevice.h>
26#include <linux/timer.h>
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>
1da177e4
LT		 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
80enum sixpack_flags {
81 SIXPF_ERROR, /* Parity, etc. error */
82};
83
84struct 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
1da177e4
LT		 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
1da177e4
LT		 129static void sixpack_decode(struct sixpack *, unsigned char[], int);
130static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char);
131
132/*
c0438174 133 * Perform the persistence/slottime algorithm for CSMA access. If the
1da177e4
LT		 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
138static void sp_xmit_on_air(unsigned long channel)
139{
140 struct sixpack *sp = (struct sixpack *) channel;
c0438174 141 int actual, when = sp->slottime;
1da177e4
LT		 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;
f34d7a5b 148 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
1da177e4 149 sp->tx_enable = 1;
f34d7a5b 150 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
1da177e4
LT		 151 sp->xleft -= actual;
152 sp->xhead += actual;
153 sp->led_state = 0x60;
f34d7a5b 154 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
1da177e4
LT		 155 sp->status2 = 0;
156 } else
c0438174 157 mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100);
1da177e4
LT		 158}
159
160/* ----> 6pack timer interrupt handler and friends. <---- */
1da177e4
LT		 161
162/* Encapsulate one AX.25 frame and stuff into a TTY queue. */
163static 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;
f34d7a5b 220 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
1da177e4 221 sp->tx_enable = 1;
f34d7a5b 222 actual = sp->tty->ops->write(sp->tty, sp->xbuff, count);
1da177e4
LT		 223 sp->xleft = count - actual;
224 sp->xhead = sp->xbuff + actual;
225 sp->led_state = 0x60;
f34d7a5b 226 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
1da177e4
LT		 227 } else {
228 sp->xleft = count;
229 sp->xhead = sp->xbuff;
230 sp->status2 = count;
c0438174 231 sp_xmit_on_air((unsigned long)sp);
1da177e4
LT		 232 }
233
234 return;
235
236out_drop:
de0561c4 237 sp->dev->stats.tx_dropped++;
1da177e4
LT		 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
245static 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);
de0561c4 252 dev->stats.tx_bytes += skb->len;
1da177e4
LT		 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
261static 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. */
271static 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 */
287static int sp_header(struct sk_buff *skb, struct net_device *dev,
3b04ddde
SH		 288 unsigned short type, const void *daddr,
289 const void *saddr, unsigned len)
1da177e4
LT		 290{
291#ifdef CONFIG_INET
d9a19d20 292 if (type != ETH_P_AX25)
6f74998e 293 return ax25_hard_header(skb, dev, type, daddr, saddr, len);
1da177e4
LT		 294#endif
295 return 0;
296}
297
1da177e4
LT		 298static int sp_set_mac_address(struct net_device *dev, void *addr)
299{
300 struct sockaddr_ax25 *sa = addr;
301
932ff279 302 netif_tx_lock_bh(dev);
e308a5d8 303 netif_addr_lock(dev);
1da177e4 304 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
e308a5d8 305 netif_addr_unlock(dev);
932ff279 306 netif_tx_unlock_bh(dev);
1da177e4
LT		 307
308 return 0;
309}
310
311static 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
3b04ddde
SH		 320static const struct header_ops sp_header_ops = {
321 .create = sp_header,
322 .rebuild = sp_rebuild_header,
323};
324
1da177e4
LT		 325static void sp_setup(struct net_device *dev)
326{
1da177e4
LT		 327 /* Finish setting up the DEVICE info. */
328 dev->mtu = SIXP_MTU;
329 dev->hard_start_xmit = sp_xmit;
330 dev->open = sp_open_dev;
331 dev->destructor = free_netdev;
332 dev->stop = sp_close;
3b04ddde 333
1da177e4
LT		 334 dev->set_mac_address = sp_set_mac_address;
335 dev->hard_header_len = AX25_MAX_HEADER_LEN;
3b04ddde
SH		 336 dev->header_ops = &sp_header_ops;
337
1da177e4
LT		 338 dev->addr_len = AX25_ADDR_LEN;
339 dev->type = ARPHRD_AX25;
340 dev->tx_queue_len = 10;
1da177e4
LT		 341 dev->tx_timeout = NULL;
342
343 /* Only activated in AX.25 mode */
15b1c0e8
RB		 344 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
345 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
1da177e4 346
1da177e4
LT		 347 dev->flags = 0;
348}
349
350/* Send one completely decapsulated IP datagram to the IP layer. */
351
352/*
353 * This is the routine that sends the received data to the kernel AX.25.
354 * 'cmd' is the KISS command. For AX.25 data, it is zero.
355 */
356
357static void sp_bump(struct sixpack *sp, char cmd)
358{
359 struct sk_buff *skb;
360 int count;
361 unsigned char *ptr;
362
363 count = sp->rcount + 1;
364
de0561c4 365 sp->dev->stats.rx_bytes += count;
1da177e4
LT		 366
367 if ((skb = dev_alloc_skb(count)) == NULL)
368 goto out_mem;
369
1da177e4
LT		 370 ptr = skb_put(skb, count);
371 *ptr++ = cmd; /* KISS command */
372
373 memcpy(ptr, sp->cooked_buf + 1, count);
56cb5156 374 skb->protocol = ax25_type_trans(skb, sp->dev);
1da177e4
LT		 375 netif_rx(skb);
376 sp->dev->last_rx = jiffies;
de0561c4 377 sp->dev->stats.rx_packets++;
1da177e4
LT		 378
379 return;
380
381out_mem:
de0561c4 382 sp->dev->stats.rx_dropped++;
1da177e4
LT		 383}
384
385
386/* ----------------------------------------------------------------------- */
387
388/*
389 * We have a potential race on dereferencing tty->disc_data, because the tty
390 * layer provides no locking at all - thus one cpu could be running
391 * sixpack_receive_buf while another calls sixpack_close, which zeroes
392 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
393 * best way to fix this is to use a rwlock in the tty struct, but for now we
394 * use a single global rwlock for all ttys in ppp line discipline.
395 */
396static DEFINE_RWLOCK(disc_data_lock);
397
398static struct sixpack *sp_get(struct tty_struct *tty)
399{
400 struct sixpack *sp;
401
402 read_lock(&disc_data_lock);
403 sp = tty->disc_data;
404 if (sp)
405 atomic_inc(&sp->refcnt);
406 read_unlock(&disc_data_lock);
407
408 return sp;
409}
410
411static void sp_put(struct sixpack *sp)
412{
413 if (atomic_dec_and_test(&sp->refcnt))
414 up(&sp->dead_sem);
415}
416
417/*
418 * Called by the TTY driver when there's room for more data. If we have
419 * more packets to send, we send them here.
420 */
421static void sixpack_write_wakeup(struct tty_struct *tty)
422{
423 struct sixpack *sp = sp_get(tty);
424 int actual;
425
426 if (!sp)
427 return;
428 if (sp->xleft <= 0) {
429 /* Now serial buffer is almost free & we can start
430 * transmission of another packet */
de0561c4 431 sp->dev->stats.tx_packets++;
1da177e4
LT		 432 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
433 sp->tx_enable = 0;
434 netif_wake_queue(sp->dev);
435 goto out;
436 }
437
438 if (sp->tx_enable) {
f34d7a5b 439 actual = tty->ops->write(tty, sp->xhead, sp->xleft);
1da177e4
LT		 440 sp->xleft -= actual;
441 sp->xhead += actual;
442 }
443
444out:
445 sp_put(sp);
446}
447
448/* ----------------------------------------------------------------------- */
449
1da177e4
LT		 450/*
451 * Handle the 'receiver data ready' interrupt.
452 * This function is called by the 'tty_io' module in the kernel when
453 * a block of 6pack data has been received, which can now be decapsulated
454 * and sent on to some IP layer for further processing.
455 */
456static void sixpack_receive_buf(struct tty_struct *tty,
457 const unsigned char *cp, char *fp, int count)
458{
459 struct sixpack *sp;
460 unsigned char buf[512];
461 int count1;
462
463 if (!count)
464 return;
465
466 sp = sp_get(tty);
467 if (!sp)
468 return;
469
470 memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf));
471
472 /* Read the characters out of the buffer */
473
474 count1 = count;
475 while (count) {
476 count--;
477 if (fp && *fp++) {
478 if (!test_and_set_bit(SIXPF_ERROR, &sp->flags))
de0561c4 479 sp->dev->stats.rx_errors++;
1da177e4
LT		 480 continue;
481 }
482 }
483 sixpack_decode(sp, buf, count1);
484
485 sp_put(sp);
39c2e60f 486 tty_unthrottle(tty);
1da177e4
LT		 487}
488
489/*
490 * Try to resync the TNC. Called by the resync timer defined in
491 * decode_prio_command
492 */
493
494#define TNC_UNINITIALIZED 0
495#define TNC_UNSYNC_STARTUP 1
496#define TNC_UNSYNCED 2
497#define TNC_IN_SYNC 3
498
499static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
500{
501 char *msg;
502
503 switch (new_tnc_state) {
504 default: /* gcc oh piece-o-crap ... */
505 case TNC_UNSYNC_STARTUP:
506 msg = "Synchronizing with TNC";
507 break;
508 case TNC_UNSYNCED:
509 msg = "Lost synchronization with TNC\n";
510 break;
511 case TNC_IN_SYNC:
512 msg = "Found TNC";
513 break;
514 }
515
516 sp->tnc_state = new_tnc_state;
517 printk(KERN_INFO "%s: %s\n", sp->dev->name, msg);
518}
519
520static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
521{
522 int old_tnc_state = sp->tnc_state;
523
524 if (old_tnc_state != new_tnc_state)
525 __tnc_set_sync_state(sp, new_tnc_state);
526}
527
528static void resync_tnc(unsigned long channel)
529{
530 struct sixpack *sp = (struct sixpack *) channel;
531 static char resync_cmd = 0xe8;
532
533 /* clear any data that might have been received */
534
535 sp->rx_count = 0;
536 sp->rx_count_cooked = 0;
537
538 /* reset state machine */
539
540 sp->status = 1;
541 sp->status1 = 1;
542 sp->status2 = 0;
543
544 /* resync the TNC */
545
546 sp->led_state = 0x60;
f34d7a5b
AC		 547 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
548 sp->tty->ops->write(sp->tty, &resync_cmd, 1);
1da177e4
LT		 549
550
551 /* Start resync timer again -- the TNC might be still absent */
552
553 del_timer(&sp->resync_t);
554 sp->resync_t.data = (unsigned long) sp;
555 sp->resync_t.function = resync_tnc;
556 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT;
557 add_timer(&sp->resync_t);
558}
559
560static inline int tnc_init(struct sixpack *sp)
561{
562 unsigned char inbyte = 0xe8;
563
564 tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP);
565
f34d7a5b 566 sp->tty->ops->write(sp->tty, &inbyte, 1);
1da177e4
LT		 567
568 del_timer(&sp->resync_t);
569 sp->resync_t.data = (unsigned long) sp;
570 sp->resync_t.function = resync_tnc;
571 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT;
572 add_timer(&sp->resync_t);
573
574 return 0;
575}
576
577/*
578 * Open the high-level part of the 6pack channel.
579 * This function is called by the TTY module when the
580 * 6pack line discipline is called for. Because we are
581 * sure the tty line exists, we only have to link it to
582 * a free 6pcack channel...
583 */
584static int sixpack_open(struct tty_struct *tty)
585{
586 char *rbuff = NULL, *xbuff = NULL;
587 struct net_device *dev;
588 struct sixpack *sp;
589 unsigned long len;
590 int err = 0;
591
592 if (!capable(CAP_NET_ADMIN))
593 return -EPERM;
f34d7a5b
AC		 594 if (tty->ops->write == NULL)
595 return -EOPNOTSUPP;
1da177e4
LT		 596
597 dev = alloc_netdev(sizeof(struct sixpack), "sp%d", sp_setup);
598 if (!dev) {
599 err = -ENOMEM;
600 goto out;
601 }
602
603 sp = netdev_priv(dev);
604 sp->dev = dev;
605
606 spin_lock_init(&sp->lock);
607 atomic_set(&sp->refcnt, 1);
608 init_MUTEX_LOCKED(&sp->dead_sem);
609
610 /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */
611
612 len = dev->mtu * 2;
613
614 rbuff = kmalloc(len + 4, GFP_KERNEL);
615 xbuff = kmalloc(len + 4, GFP_KERNEL);
616
617 if (rbuff == NULL || xbuff == NULL) {
618 err = -ENOBUFS;
619 goto out_free;
620 }
621
622 spin_lock_bh(&sp->lock);
623
624 sp->tty = tty;
625
626 sp->rbuff = rbuff;
627 sp->xbuff = xbuff;
628
629 sp->mtu = AX25_MTU + 73;
630 sp->buffsize = len;
631 sp->rcount = 0;
632 sp->rx_count = 0;
633 sp->rx_count_cooked = 0;
634 sp->xleft = 0;
635
636 sp->flags = 0; /* Clear ESCAPE & ERROR flags */
637
638 sp->duplex = 0;
639 sp->tx_delay = SIXP_TXDELAY;
640 sp->persistence = SIXP_PERSIST;
641 sp->slottime = SIXP_SLOTTIME;
642 sp->led_state = 0x60;
643 sp->status = 1;
644 sp->status1 = 1;
645 sp->status2 = 0;
646 sp->tx_enable = 0;
647
648 netif_start_queue(dev);
649
650 init_timer(&sp->tx_t);
84a2ea1c
RB		 651 sp->tx_t.function = sp_xmit_on_air;
652 sp->tx_t.data = (unsigned long) sp;
653
1da177e4
LT		 654 init_timer(&sp->resync_t);
655
656 spin_unlock_bh(&sp->lock);
657
658 /* Done. We have linked the TTY line to a channel. */
659 tty->disc_data = sp;
33f0f88f 660 tty->receive_room = 65536;
1da177e4
LT		 661
662 /* Now we're ready to register. */
663 if (register_netdev(dev))
664 goto out_free;
665
666 tnc_init(sp);
667
668 return 0;
669
670out_free:
671 kfree(xbuff);
672 kfree(rbuff);
673
674 if (dev)
675 free_netdev(dev);
676
677out:
678 return err;
679}
680
681
682/*
683 * Close down a 6pack channel.
684 * This means flushing out any pending queues, and then restoring the
685 * TTY line discipline to what it was before it got hooked to 6pack
686 * (which usually is TTY again).
687 */
688static void sixpack_close(struct tty_struct *tty)
689{
690 struct sixpack *sp;
691
692 write_lock(&disc_data_lock);
693 sp = tty->disc_data;
694 tty->disc_data = NULL;
695 write_unlock(&disc_data_lock);
79ea13ce 696 if (!sp)
1da177e4
LT		 697 return;
698
699 /*
700 * We have now ensured that nobody can start using ap from now on, but
701 * we have to wait for all existing users to finish.
702 */
703 if (!atomic_dec_and_test(&sp->refcnt))
704 down(&sp->dead_sem);
705
706 unregister_netdev(sp->dev);
707
708 del_timer(&sp->tx_t);
709 del_timer(&sp->resync_t);
710
711 /* Free all 6pack frame buffers. */
712 kfree(sp->rbuff);
713 kfree(sp->xbuff);
714}
715
716/* Perform I/O control on an active 6pack channel. */
717static int sixpack_ioctl(struct tty_struct *tty, struct file *file,
718 unsigned int cmd, unsigned long arg)
719{
720 struct sixpack *sp = sp_get(tty);
721 struct net_device *dev = sp->dev;
722 unsigned int tmp, err;
723
724 if (!sp)
725 return -ENXIO;
726
727 switch(cmd) {
728 case SIOCGIFNAME:
729 err = copy_to_user((void __user *) arg, dev->name,
730 strlen(dev->name) + 1) ? -EFAULT : 0;
731 break;
732
733 case SIOCGIFENCAP:
734 err = put_user(0, (int __user *) arg);
735 break;
736
737 case SIOCSIFENCAP:
738 if (get_user(tmp, (int __user *) arg)) {
739 err = -EFAULT;
740 break;
741 }
742
743 sp->mode = tmp;
744 dev->addr_len = AX25_ADDR_LEN;
745 dev->hard_header_len = AX25_KISS_HEADER_LEN +
746 AX25_MAX_HEADER_LEN + 3;
747 dev->type = ARPHRD_AX25;
748
749 err = 0;
750 break;
751
752 case SIOCSIFHWADDR: {
753 char addr[AX25_ADDR_LEN];
754
755 if (copy_from_user(&addr,
756 (void __user *) arg, AX25_ADDR_LEN)) {
d0127539
AC		 757 err = -EFAULT;
758 break;
759 }
1da177e4 760
d0127539
AC		 761 netif_tx_lock_bh(dev);
762 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN);
763 netif_tx_unlock_bh(dev);
1da177e4 764
d0127539
AC		 765 err = 0;
766 break;
767 }
1da177e4
LT		 768
769 default:
d0127539 770 err = tty_mode_ioctl(tty, file, cmd, arg);
1da177e4
LT		 771 }
772
773 sp_put(sp);
774
775 return err;
776}
777
a352def2 778static struct tty_ldisc_ops sp_ldisc = {
1da177e4
LT		 779 .owner = THIS_MODULE,
780 .magic = TTY_LDISC_MAGIC,
781 .name = "6pack",
782 .open = sixpack_open,
783 .close = sixpack_close,
784 .ioctl = sixpack_ioctl,
785 .receive_buf = sixpack_receive_buf,
1da177e4
LT		 786 .write_wakeup = sixpack_write_wakeup,
787};
788
789/* Initialize 6pack control device -- register 6pack line discipline */
790
791static char msg_banner[] __initdata = KERN_INFO \
792 "AX.25: 6pack driver, " SIXPACK_VERSION "\n";
793static char msg_regfail[] __initdata = KERN_ERR \
794 "6pack: can't register line discipline (err = %d)\n";
795
796static int __init sixpack_init_driver(void)
797{
798 int status;
799
800 printk(msg_banner);
801
802 /* Register the provided line protocol discipline */
803 if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0)
804 printk(msg_regfail, status);
805
806 return status;
807}
808
809static const char msg_unregfail[] __exitdata = KERN_ERR \
810 "6pack: can't unregister line discipline (err = %d)\n";
811
812static void __exit sixpack_exit_driver(void)
813{
814 int ret;
815
64ccd715 816 if ((ret = tty_unregister_ldisc(N_6PACK)))
1da177e4
LT		 817 printk(msg_unregfail, ret);
818}
819
820/* encode an AX.25 packet into 6pack */
821
822static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw,
823 int length, unsigned char tx_delay)
824{
825 int count = 0;
826 unsigned char checksum = 0, buf[400];
827 int raw_count = 0;
828
829 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK;
830 tx_buf_raw[raw_count++] = SIXP_SEOF;
831
832 buf[0] = tx_delay;
833 for (count = 1; count < length; count++)
834 buf[count] = tx_buf[count];
835
836 for (count = 0; count < length; count++)
837 checksum += buf[count];
838 buf[length] = (unsigned char) 0xff - checksum;
839
840 for (count = 0; count <= length; count++) {
841 if ((count % 3) == 0) {
842 tx_buf_raw[raw_count++] = (buf[count] & 0x3f);
843 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30);
844 } else if ((count % 3) == 1) {
845 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f);
846 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c);
847 } else {
848 tx_buf_raw[raw_count++] |= (buf[count] & 0x03);
849 tx_buf_raw[raw_count++] = (buf[count] >> 2);
850 }
851 }
852 if ((length % 3) != 2)
853 raw_count++;
854 tx_buf_raw[raw_count++] = SIXP_SEOF;
855 return raw_count;
856}
857
858/* decode 4 sixpack-encoded bytes into 3 data bytes */
859
860static void decode_data(struct sixpack *sp, unsigned char inbyte)
861{
862 unsigned char *buf;
863
864 if (sp->rx_count != 3) {
865 sp->raw_buf[sp->rx_count++] = inbyte;
866
867 return;
868 }
869
870 buf = sp->raw_buf;
871 sp->cooked_buf[sp->rx_count_cooked++] =
872 buf[0] | ((buf[1] << 2) & 0xc0);
873 sp->cooked_buf[sp->rx_count_cooked++] =
874 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0);
875 sp->cooked_buf[sp->rx_count_cooked++] =
876 (buf[2] & 0x03) | (inbyte << 2);
877 sp->rx_count = 0;
878}
879
880/* identify and execute a 6pack priority command byte */
881
882static void decode_prio_command(struct sixpack *sp, unsigned char cmd)
883{
884 unsigned char channel;
885 int actual;
886
887 channel = cmd & SIXP_CHN_MASK;
888 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */
889
890 /* RX and DCD flags can only be set in the same prio command,
891 if the DCD flag has been set without the RX flag in the previous
892 prio command. If DCD has not been set before, something in the
893 transmission has gone wrong. In this case, RX and DCD are
894 cleared in order to prevent the decode_data routine from
895 reading further data that might be corrupt. */
896
897 if (((sp->status & SIXP_DCD_MASK) == 0) &&
898 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) {
899 if (sp->status != 1)
900 printk(KERN_DEBUG "6pack: protocol violation\n");
901 else
902 sp->status = 0;
95f6134e 903 cmd &= ~SIXP_RX_DCD_MASK;
1da177e4
LT		 904 }
905 sp->status = cmd & SIXP_PRIO_DATA_MASK;
906 } else { /* output watchdog char if idle */
907 if ((sp->status2 != 0) && (sp->duplex == 1)) {
908 sp->led_state = 0x70;
f34d7a5b 909 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
1da177e4 910 sp->tx_enable = 1;
f34d7a5b 911 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
1da177e4
LT		 912 sp->xleft -= actual;
913 sp->xhead += actual;
914 sp->led_state = 0x60;
915 sp->status2 = 0;
916
917 }
918 }
919
920 /* needed to trigger the TNC watchdog */
f34d7a5b 921 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
1da177e4
LT		 922
923 /* if the state byte has been received, the TNC is present,
924 so the resync timer can be reset. */
925
926 if (sp->tnc_state == TNC_IN_SYNC) {
927 del_timer(&sp->resync_t);
928 sp->resync_t.data = (unsigned long) sp;
929 sp->resync_t.function = resync_tnc;
930 sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT;
931 add_timer(&sp->resync_t);
932 }
933
934 sp->status1 = cmd & SIXP_PRIO_DATA_MASK;
935}
936
937/* identify and execute a standard 6pack command byte */
938
939static void decode_std_command(struct sixpack *sp, unsigned char cmd)
940{
941 unsigned char checksum = 0, rest = 0, channel;
942 short i;
943
944 channel = cmd & SIXP_CHN_MASK;
945 switch (cmd & SIXP_CMD_MASK) { /* normal command */
946 case SIXP_SEOF:
947 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) {
948 if ((sp->status & SIXP_RX_DCD_MASK) ==
949 SIXP_RX_DCD_MASK) {
950 sp->led_state = 0x68;
f34d7a5b 951 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
1da177e4
LT		 952 }
953 } else {
954 sp->led_state = 0x60;
955 /* fill trailing bytes with zeroes */
f34d7a5b 956 sp->tty->ops->write(sp->tty, &sp->led_state, 1);
1da177e4
LT		 957 rest = sp->rx_count;
958 if (rest != 0)
959 for (i = rest; i <= 3; i++)
960 decode_data(sp, 0);
961 if (rest == 2)
962 sp->rx_count_cooked -= 2;
963 else if (rest == 3)
964 sp->rx_count_cooked -= 1;
965 for (i = 0; i < sp->rx_count_cooked; i++)
966 checksum += sp->cooked_buf[i];
967 if (checksum != SIXP_CHKSUM) {
968 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum);
969 } else {
970 sp->rcount = sp->rx_count_cooked-2;
971 sp_bump(sp, 0);
972 }
973 sp->rx_count_cooked = 0;
974 }
975 break;
976 case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n");
977 break;
978 case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n");
979 break;
980 case SIXP_RX_BUF_OVL:
981 printk(KERN_DEBUG "6pack: RX buffer overflow\n");
982 }
983}
984
985/* decode a 6pack packet */
986
987static void
988sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count)
989{
990 unsigned char inbyte;
991 int count1;
992
993 for (count1 = 0; count1 < count; count1++) {
994 inbyte = pre_rbuff[count1];
995 if (inbyte == SIXP_FOUND_TNC) {
996 tnc_set_sync_state(sp, TNC_IN_SYNC);
997 del_timer(&sp->resync_t);
998 }
999 if ((inbyte & SIXP_PRIO_CMD_MASK) != 0)
1000 decode_prio_command(sp, inbyte);
1001 else if ((inbyte & SIXP_STD_CMD_MASK) != 0)
1002 decode_std_command(sp, inbyte);
1003 else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)
1004 decode_data(sp, inbyte);
1005 }
1006}
1007
1008MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>");
1009MODULE_DESCRIPTION("6pack driver for AX.25");
1010MODULE_LICENSE("GPL");
1011MODULE_ALIAS_LDISC(N_6PACK);
1012
1013module_init(sixpack_init_driver);
1014module_exit(sixpack_exit_driver);
Linux kernel - Deliverables
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