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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/net/hamradio/6pack.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/net/hamradio/6pack.c')
-rw-r--r--drivers/net/hamradio/6pack.c1051
1 files changed, 1051 insertions, 0 deletions
diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
new file mode 100644
index 000000000000..067b353e1cbd
--- /dev/null
+++ b/drivers/net/hamradio/6pack.c
@@ -0,0 +1,1051 @@
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/config.h>
16#include <linux/module.h>
17#include <asm/system.h>
18#include <asm/uaccess.h>
19#include <linux/bitops.h>
20#include <linux/string.h>
21#include <linux/mm.h>
22#include <linux/interrupt.h>
23#include <linux/in.h>
24#include <linux/tty.h>
25#include <linux/errno.h>
26#include <linux/netdevice.h>
27#include <linux/timer.h>
28#include <net/ax25.h>
29#include <linux/etherdevice.h>
30#include <linux/skbuff.h>
31#include <linux/rtnetlink.h>
32#include <linux/spinlock.h>
33#include <linux/if_arp.h>
34#include <linux/init.h>
35#include <linux/ip.h>
36#include <linux/tcp.h>
37#include <asm/semaphore.h>
38#include <asm/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
81enum sixpack_flags {
82 SIXPF_ERROR, /* Parity, etc. error */
83};
84
85struct 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 /* 6pack interface statistics. */
104 struct net_device_stats stats;
105
106 int mtu; /* Our mtu (to spot changes!) */
107 int buffsize; /* Max buffers sizes */
108
109 unsigned long flags; /* Flag values/ mode etc */
110 unsigned char mode; /* 6pack mode */
111
112 /* 6pack stuff */
113 unsigned char tx_delay;
114 unsigned char persistence;
115 unsigned char slottime;
116 unsigned char duplex;
117 unsigned char led_state;
118 unsigned char status;
119 unsigned char status1;
120 unsigned char status2;
121 unsigned char tx_enable;
122 unsigned char tnc_state;
123
124 struct timer_list tx_t;
125 struct timer_list resync_t;
126 atomic_t refcnt;
127 struct semaphore dead_sem;
128 spinlock_t lock;
129};
130
131#define AX25_6PACK_HEADER_LEN 0
132
133static void sp_start_tx_timer(struct sixpack *);
134static void sixpack_decode(struct sixpack *, unsigned char[], int);
135static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char);
136
137/*
138 * perform the persistence/slottime algorithm for CSMA access. If the
139 * persistence check was successful, write the data to the serial driver.
140 * Note that in case of DAMA operation, the data is not sent here.
141 */
142
143static void sp_xmit_on_air(unsigned long channel)
144{
145 struct sixpack *sp = (struct sixpack *) channel;
146 int actual;
147 static unsigned char random;
148
149 random = random * 17 + 41;
150
151 if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) {
152 sp->led_state = 0x70;
153 sp->tty->driver->write(sp->tty, &sp->led_state, 1);
154 sp->tx_enable = 1;
155 actual = sp->tty->driver->write(sp->tty, sp->xbuff, sp->status2);
156 sp->xleft -= actual;
157 sp->xhead += actual;
158 sp->led_state = 0x60;
159 sp->tty->driver->write(sp->tty, &sp->led_state, 1);
160 sp->status2 = 0;
161 } else
162 sp_start_tx_timer(sp);
163}
164
165/* ----> 6pack timer interrupt handler and friends. <---- */
166static void sp_start_tx_timer(struct sixpack *sp)
167{
168 int when = sp->slottime;
169
170 del_timer(&sp->tx_t);
171 sp->tx_t.data = (unsigned long) sp;
172 sp->tx_t.function = sp_xmit_on_air;
173 sp->tx_t.expires = jiffies + ((when + 1) * HZ) / 100;
174 add_timer(&sp->tx_t);
175}
176
177/* Encapsulate one AX.25 frame and stuff into a TTY queue. */
178static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len)
179{
180 unsigned char *msg, *p = icp;
181 int actual, count;
182
183 if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */
184 msg = "oversized transmit packet!";
185 goto out_drop;
186 }
187
188 if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */
189 msg = "oversized transmit packet!";
190 goto out_drop;
191 }
192
193 if (p[0] > 5) {
194 msg = "invalid KISS command";
195 goto out_drop;
196 }
197
198 if ((p[0] != 0) && (len > 2)) {
199 msg = "KISS control packet too long";
200 goto out_drop;
201 }
202
203 if ((p[0] == 0) && (len < 15)) {
204 msg = "bad AX.25 packet to transmit";
205 goto out_drop;
206 }
207
208 count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay);
209 set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
210
211 switch (p[0]) {
212 case 1: sp->tx_delay = p[1];
213 return;
214 case 2: sp->persistence = p[1];
215 return;
216 case 3: sp->slottime = p[1];
217 return;
218 case 4: /* ignored */
219 return;
220 case 5: sp->duplex = p[1];
221 return;
222 }
223
224 if (p[0] != 0)
225 return;
226
227 /*
228 * In case of fullduplex or DAMA operation, we don't take care about the
229 * state of the DCD or of any timers, as the determination of the
230 * correct time to send is the job of the AX.25 layer. We send
231 * immediately after data has arrived.
232 */
233 if (sp->duplex == 1) {
234 sp->led_state = 0x70;
235 sp->tty->driver->write(sp->tty, &sp->led_state, 1);
236 sp->tx_enable = 1;
237 actual = sp->tty->driver->write(sp->tty, sp->xbuff, count);
238 sp->xleft = count - actual;
239 sp->xhead = sp->xbuff + actual;
240 sp->led_state = 0x60;
241 sp->tty->driver->write(sp->tty, &sp->led_state, 1);
242 } else {
243 sp->xleft = count;
244 sp->xhead = sp->xbuff;
245 sp->status2 = count;
246 if (sp->duplex == 0)
247 sp_start_tx_timer(sp);
248 }
249
250 return;
251
252out_drop:
253 sp->stats.tx_dropped++;
254 netif_start_queue(sp->dev);
255 if (net_ratelimit())
256 printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg);
257}
258
259/* Encapsulate an IP datagram and kick it into a TTY queue. */
260
261static int sp_xmit(struct sk_buff *skb, struct net_device *dev)
262{
263 struct sixpack *sp = netdev_priv(dev);
264
265 spin_lock_bh(&sp->lock);
266 /* We were not busy, so we are now... :-) */
267 netif_stop_queue(dev);
268 sp->stats.tx_bytes += skb->len;
269 sp_encaps(sp, skb->data, skb->len);
270 spin_unlock_bh(&sp->lock);
271
272 dev_kfree_skb(skb);
273
274 return 0;
275}
276
277static int sp_open_dev(struct net_device *dev)
278{
279 struct sixpack *sp = netdev_priv(dev);
280
281 if (sp->tty == NULL)
282 return -ENODEV;
283 return 0;
284}
285
286/* Close the low-level part of the 6pack channel. */
287static int sp_close(struct net_device *dev)
288{
289 struct sixpack *sp = netdev_priv(dev);
290
291 spin_lock_bh(&sp->lock);
292 if (sp->tty) {
293 /* TTY discipline is running. */
294 clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
295 }
296 netif_stop_queue(dev);
297 spin_unlock_bh(&sp->lock);
298
299 return 0;
300}
301
302/* Return the frame type ID */
303static int sp_header(struct sk_buff *skb, struct net_device *dev,
304 unsigned short type, void *daddr, void *saddr, unsigned len)
305{
306#ifdef CONFIG_INET
307 if (type != htons(ETH_P_AX25))
308 return ax25_encapsulate(skb, dev, type, daddr, saddr, len);
309#endif
310 return 0;
311}
312
313static struct net_device_stats *sp_get_stats(struct net_device *dev)
314{
315 struct sixpack *sp = netdev_priv(dev);
316 return &sp->stats;
317}
318
319static int sp_set_mac_address(struct net_device *dev, void *addr)
320{
321 struct sockaddr_ax25 *sa = addr;
322
323 if (sa->sax25_family != AF_AX25)
324 return -EINVAL;
325
326 if (!sa->sax25_ndigis)
327 return -EINVAL;
328
329 spin_lock_irq(&dev->xmit_lock);
330 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
331 spin_unlock_irq(&dev->xmit_lock);
332
333 return 0;
334}
335
336static int sp_rebuild_header(struct sk_buff *skb)
337{
338#ifdef CONFIG_INET
339 return ax25_rebuild_header(skb);
340#else
341 return 0;
342#endif
343}
344
345static void sp_setup(struct net_device *dev)
346{
347 static char ax25_bcast[AX25_ADDR_LEN] =
348 {'Q'<<1,'S'<<1,'T'<<1,' '<<1,' '<<1,' '<<1,'0'<<1};
349 static char ax25_test[AX25_ADDR_LEN] =
350 {'L'<<1,'I'<<1,'N'<<1,'U'<<1,'X'<<1,' '<<1,'1'<<1};
351
352 /* Finish setting up the DEVICE info. */
353 dev->mtu = SIXP_MTU;
354 dev->hard_start_xmit = sp_xmit;
355 dev->open = sp_open_dev;
356 dev->destructor = free_netdev;
357 dev->stop = sp_close;
358 dev->hard_header = sp_header;
359 dev->get_stats = sp_get_stats;
360 dev->set_mac_address = sp_set_mac_address;
361 dev->hard_header_len = AX25_MAX_HEADER_LEN;
362 dev->addr_len = AX25_ADDR_LEN;
363 dev->type = ARPHRD_AX25;
364 dev->tx_queue_len = 10;
365 dev->rebuild_header = sp_rebuild_header;
366 dev->tx_timeout = NULL;
367
368 /* Only activated in AX.25 mode */
369 memcpy(dev->broadcast, ax25_bcast, AX25_ADDR_LEN);
370 memcpy(dev->dev_addr, ax25_test, AX25_ADDR_LEN);
371
372 SET_MODULE_OWNER(dev);
373
374 dev->flags = 0;
375}
376
377/* Send one completely decapsulated IP datagram to the IP layer. */
378
379/*
380 * This is the routine that sends the received data to the kernel AX.25.
381 * 'cmd' is the KISS command. For AX.25 data, it is zero.
382 */
383
384static void sp_bump(struct sixpack *sp, char cmd)
385{
386 struct sk_buff *skb;
387 int count;
388 unsigned char *ptr;
389
390 count = sp->rcount + 1;
391
392 sp->stats.rx_bytes += count;
393
394 if ((skb = dev_alloc_skb(count)) == NULL)
395 goto out_mem;
396
397 skb->dev = sp->dev;
398 ptr = skb_put(skb, count);
399 *ptr++ = cmd; /* KISS command */
400
401 memcpy(ptr, sp->cooked_buf + 1, count);
402 skb->mac.raw = skb->data;
403 skb->protocol = htons(ETH_P_AX25);
404 netif_rx(skb);
405 sp->dev->last_rx = jiffies;
406 sp->stats.rx_packets++;
407
408 return;
409
410out_mem:
411 sp->stats.rx_dropped++;
412}
413
414
415/* ----------------------------------------------------------------------- */
416
417/*
418 * We have a potential race on dereferencing tty->disc_data, because the tty
419 * layer provides no locking at all - thus one cpu could be running
420 * sixpack_receive_buf while another calls sixpack_close, which zeroes
421 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The
422 * best way to fix this is to use a rwlock in the tty struct, but for now we
423 * use a single global rwlock for all ttys in ppp line discipline.
424 */
425static DEFINE_RWLOCK(disc_data_lock);
426
427static struct sixpack *sp_get(struct tty_struct *tty)
428{
429 struct sixpack *sp;
430
431 read_lock(&disc_data_lock);
432 sp = tty->disc_data;
433 if (sp)
434 atomic_inc(&sp->refcnt);
435 read_unlock(&disc_data_lock);
436
437 return sp;
438}
439
440static void sp_put(struct sixpack *sp)
441{
442 if (atomic_dec_and_test(&sp->refcnt))
443 up(&sp->dead_sem);
444}
445
446/*
447 * Called by the TTY driver when there's room for more data. If we have
448 * more packets to send, we send them here.
449 */
450static void sixpack_write_wakeup(struct tty_struct *tty)
451{
452 struct sixpack *sp = sp_get(tty);
453 int actual;
454
455 if (!sp)
456 return;
457 if (sp->xleft <= 0) {
458 /* Now serial buffer is almost free & we can start
459 * transmission of another packet */
460 sp->stats.tx_packets++;
461 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
462 sp->tx_enable = 0;
463 netif_wake_queue(sp->dev);
464 goto out;
465 }
466
467 if (sp->tx_enable) {
468 actual = tty->driver->write(tty, sp->xhead, sp->xleft);
469 sp->xleft -= actual;
470 sp->xhead += actual;
471 }
472
473out:
474 sp_put(sp);
475}
476
477/* ----------------------------------------------------------------------- */
478
479static int sixpack_receive_room(struct tty_struct *tty)
480{
481 return 65536; /* We can handle an infinite amount of data. :-) */
482}
483
484/*
485 * Handle the 'receiver data ready' interrupt.
486 * This function is called by the 'tty_io' module in the kernel when
487 * a block of 6pack data has been received, which can now be decapsulated
488 * and sent on to some IP layer for further processing.
489 */
490static void sixpack_receive_buf(struct tty_struct *tty,
491 const unsigned char *cp, char *fp, int count)
492{
493 struct sixpack *sp;
494 unsigned char buf[512];
495 int count1;
496
497 if (!count)
498 return;
499
500 sp = sp_get(tty);
501 if (!sp)
502 return;
503
504 memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf));
505
506 /* Read the characters out of the buffer */
507
508 count1 = count;
509 while (count) {
510 count--;
511 if (fp && *fp++) {
512 if (!test_and_set_bit(SIXPF_ERROR, &sp->flags))
513 sp->stats.rx_errors++;
514 continue;
515 }
516 }
517 sixpack_decode(sp, buf, count1);
518
519 sp_put(sp);
520 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags)
521 && tty->driver->unthrottle)
522 tty->driver->unthrottle(tty);
523}
524
525/*
526 * Try to resync the TNC. Called by the resync timer defined in
527 * decode_prio_command
528 */
529
530#define TNC_UNINITIALIZED 0
531#define TNC_UNSYNC_STARTUP 1
532#define TNC_UNSYNCED 2
533#define TNC_IN_SYNC 3
534
535static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
536{
537 char *msg;
538
539 switch (new_tnc_state) {
540 default: /* gcc oh piece-o-crap ... */
541 case TNC_UNSYNC_STARTUP:
542 msg = "Synchronizing with TNC";
543 break;
544 case TNC_UNSYNCED:
545 msg = "Lost synchronization with TNC\n";
546 break;
547 case TNC_IN_SYNC:
548 msg = "Found TNC";
549 break;
550 }
551
552 sp->tnc_state = new_tnc_state;
553 printk(KERN_INFO "%s: %s\n", sp->dev->name, msg);
554}
555
556static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
557{
558 int old_tnc_state = sp->tnc_state;
559
560 if (old_tnc_state != new_tnc_state)
561 __tnc_set_sync_state(sp, new_tnc_state);
562}
563
564static void resync_tnc(unsigned long channel)
565{
566 struct sixpack *sp = (struct sixpack *) channel;
567 static char resync_cmd = 0xe8;
568
569 /* clear any data that might have been received */
570
571 sp->rx_count = 0;
572 sp->rx_count_cooked = 0;
573
574 /* reset state machine */
575
576 sp->status = 1;
577 sp->status1 = 1;
578 sp->status2 = 0;
579
580 /* resync the TNC */
581
582 sp->led_state = 0x60;
583 sp->tty->driver->write(sp->tty, &sp->led_state, 1);
584 sp->tty->driver->write(sp->tty, &resync_cmd, 1);
585
586
587 /* Start resync timer again -- the TNC might be still absent */
588
589 del_timer(&sp->resync_t);
590 sp->resync_t.data = (unsigned long) sp;
591 sp->resync_t.function = resync_tnc;
592 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT;
593 add_timer(&sp->resync_t);
594}
595
596static inline int tnc_init(struct sixpack *sp)
597{
598 unsigned char inbyte = 0xe8;
599
600 tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP);
601
602 sp->tty->driver->write(sp->tty, &inbyte, 1);
603
604 del_timer(&sp->resync_t);
605 sp->resync_t.data = (unsigned long) sp;
606 sp->resync_t.function = resync_tnc;
607 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT;
608 add_timer(&sp->resync_t);
609
610 return 0;
611}
612
613/*
614 * Open the high-level part of the 6pack channel.
615 * This function is called by the TTY module when the
616 * 6pack line discipline is called for. Because we are
617 * sure the tty line exists, we only have to link it to
618 * a free 6pcack channel...
619 */
620static int sixpack_open(struct tty_struct *tty)
621{
622 char *rbuff = NULL, *xbuff = NULL;
623 struct net_device *dev;
624 struct sixpack *sp;
625 unsigned long len;
626 int err = 0;
627
628 if (!capable(CAP_NET_ADMIN))
629 return -EPERM;
630
631 dev = alloc_netdev(sizeof(struct sixpack), "sp%d", sp_setup);
632 if (!dev) {
633 err = -ENOMEM;
634 goto out;
635 }
636
637 sp = netdev_priv(dev);
638 sp->dev = dev;
639
640 spin_lock_init(&sp->lock);
641 atomic_set(&sp->refcnt, 1);
642 init_MUTEX_LOCKED(&sp->dead_sem);
643
644 /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */
645
646 len = dev->mtu * 2;
647
648 rbuff = kmalloc(len + 4, GFP_KERNEL);
649 xbuff = kmalloc(len + 4, GFP_KERNEL);
650
651 if (rbuff == NULL || xbuff == NULL) {
652 err = -ENOBUFS;
653 goto out_free;
654 }
655
656 spin_lock_bh(&sp->lock);
657
658 sp->tty = tty;
659
660 sp->rbuff = rbuff;
661 sp->xbuff = xbuff;
662
663 sp->mtu = AX25_MTU + 73;
664 sp->buffsize = len;
665 sp->rcount = 0;
666 sp->rx_count = 0;
667 sp->rx_count_cooked = 0;
668 sp->xleft = 0;
669
670 sp->flags = 0; /* Clear ESCAPE & ERROR flags */
671
672 sp->duplex = 0;
673 sp->tx_delay = SIXP_TXDELAY;
674 sp->persistence = SIXP_PERSIST;
675 sp->slottime = SIXP_SLOTTIME;
676 sp->led_state = 0x60;
677 sp->status = 1;
678 sp->status1 = 1;
679 sp->status2 = 0;
680 sp->tx_enable = 0;
681
682 netif_start_queue(dev);
683
684 init_timer(&sp->tx_t);
685 init_timer(&sp->resync_t);
686
687 spin_unlock_bh(&sp->lock);
688
689 /* Done. We have linked the TTY line to a channel. */
690 tty->disc_data = sp;
691
692 /* Now we're ready to register. */
693 if (register_netdev(dev))
694 goto out_free;
695
696 tnc_init(sp);
697
698 return 0;
699
700out_free:
701 kfree(xbuff);
702 kfree(rbuff);
703
704 if (dev)
705 free_netdev(dev);
706
707out:
708 return err;
709}
710
711
712/*
713 * Close down a 6pack channel.
714 * This means flushing out any pending queues, and then restoring the
715 * TTY line discipline to what it was before it got hooked to 6pack
716 * (which usually is TTY again).
717 */
718static void sixpack_close(struct tty_struct *tty)
719{
720 struct sixpack *sp;
721
722 write_lock(&disc_data_lock);
723 sp = tty->disc_data;
724 tty->disc_data = NULL;
725 write_unlock(&disc_data_lock);
726 if (sp == 0)
727 return;
728
729 /*
730 * We have now ensured that nobody can start using ap from now on, but
731 * we have to wait for all existing users to finish.
732 */
733 if (!atomic_dec_and_test(&sp->refcnt))
734 down(&sp->dead_sem);
735
736 unregister_netdev(sp->dev);
737
738 del_timer(&sp->tx_t);
739 del_timer(&sp->resync_t);
740
741 /* Free all 6pack frame buffers. */
742 kfree(sp->rbuff);
743 kfree(sp->xbuff);
744}
745
746/* Perform I/O control on an active 6pack channel. */
747static int sixpack_ioctl(struct tty_struct *tty, struct file *file,
748 unsigned int cmd, unsigned long arg)
749{
750 struct sixpack *sp = sp_get(tty);
751 struct net_device *dev = sp->dev;
752 unsigned int tmp, err;
753
754 if (!sp)
755 return -ENXIO;
756
757 switch(cmd) {
758 case SIOCGIFNAME:
759 err = copy_to_user((void __user *) arg, dev->name,
760 strlen(dev->name) + 1) ? -EFAULT : 0;
761 break;
762
763 case SIOCGIFENCAP:
764 err = put_user(0, (int __user *) arg);
765 break;
766
767 case SIOCSIFENCAP:
768 if (get_user(tmp, (int __user *) arg)) {
769 err = -EFAULT;
770 break;
771 }
772
773 sp->mode = tmp;
774 dev->addr_len = AX25_ADDR_LEN;
775 dev->hard_header_len = AX25_KISS_HEADER_LEN +
776 AX25_MAX_HEADER_LEN + 3;
777 dev->type = ARPHRD_AX25;
778
779 err = 0;
780 break;
781
782 case SIOCSIFHWADDR: {
783 char addr[AX25_ADDR_LEN];
784
785 if (copy_from_user(&addr,
786 (void __user *) arg, AX25_ADDR_LEN)) {
787 err = -EFAULT;
788 break;
789 }
790
791 spin_lock_irq(&dev->xmit_lock);
792 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN);
793 spin_unlock_irq(&dev->xmit_lock);
794
795 err = 0;
796 break;
797 }
798
799 /* Allow stty to read, but not set, the serial port */
800 case TCGETS:
801 case TCGETA:
802 err = n_tty_ioctl(tty, (struct file *) file, cmd, arg);
803 break;
804
805 default:
806 err = -ENOIOCTLCMD;
807 }
808
809 sp_put(sp);
810
811 return err;
812}
813
814static struct tty_ldisc sp_ldisc = {
815 .owner = THIS_MODULE,
816 .magic = TTY_LDISC_MAGIC,
817 .name = "6pack",
818 .open = sixpack_open,
819 .close = sixpack_close,
820 .ioctl = sixpack_ioctl,
821 .receive_buf = sixpack_receive_buf,
822 .receive_room = sixpack_receive_room,
823 .write_wakeup = sixpack_write_wakeup,
824};
825
826/* Initialize 6pack control device -- register 6pack line discipline */
827
828static char msg_banner[] __initdata = KERN_INFO \
829 "AX.25: 6pack driver, " SIXPACK_VERSION "\n";
830static char msg_regfail[] __initdata = KERN_ERR \
831 "6pack: can't register line discipline (err = %d)\n";
832
833static int __init sixpack_init_driver(void)
834{
835 int status;
836
837 printk(msg_banner);
838
839 /* Register the provided line protocol discipline */
840 if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0)
841 printk(msg_regfail, status);
842
843 return status;
844}
845
846static const char msg_unregfail[] __exitdata = KERN_ERR \
847 "6pack: can't unregister line discipline (err = %d)\n";
848
849static void __exit sixpack_exit_driver(void)
850{
851 int ret;
852
853 if ((ret = tty_register_ldisc(N_6PACK, NULL)))
854 printk(msg_unregfail, ret);
855}
856
857/* encode an AX.25 packet into 6pack */
858
859static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw,
860 int length, unsigned char tx_delay)
861{
862 int count = 0;
863 unsigned char checksum = 0, buf[400];
864 int raw_count = 0;
865
866 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK;
867 tx_buf_raw[raw_count++] = SIXP_SEOF;
868
869 buf[0] = tx_delay;
870 for (count = 1; count < length; count++)
871 buf[count] = tx_buf[count];
872
873 for (count = 0; count < length; count++)
874 checksum += buf[count];
875 buf[length] = (unsigned char) 0xff - checksum;
876
877 for (count = 0; count <= length; count++) {
878 if ((count % 3) == 0) {
879 tx_buf_raw[raw_count++] = (buf[count] & 0x3f);
880 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30);
881 } else if ((count % 3) == 1) {
882 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f);
883 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c);
884 } else {
885 tx_buf_raw[raw_count++] |= (buf[count] & 0x03);
886 tx_buf_raw[raw_count++] = (buf[count] >> 2);
887 }
888 }
889 if ((length % 3) != 2)
890 raw_count++;
891 tx_buf_raw[raw_count++] = SIXP_SEOF;
892 return raw_count;
893}
894
895/* decode 4 sixpack-encoded bytes into 3 data bytes */
896
897static void decode_data(struct sixpack *sp, unsigned char inbyte)
898{
899 unsigned char *buf;
900
901 if (sp->rx_count != 3) {
902 sp->raw_buf[sp->rx_count++] = inbyte;
903
904 return;
905 }
906
907 buf = sp->raw_buf;
908 sp->cooked_buf[sp->rx_count_cooked++] =
909 buf[0] | ((buf[1] << 2) & 0xc0);
910 sp->cooked_buf[sp->rx_count_cooked++] =
911 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0);
912 sp->cooked_buf[sp->rx_count_cooked++] =
913 (buf[2] & 0x03) | (inbyte << 2);
914 sp->rx_count = 0;
915}
916
917/* identify and execute a 6pack priority command byte */
918
919static void decode_prio_command(struct sixpack *sp, unsigned char cmd)
920{
921 unsigned char channel;
922 int actual;
923
924 channel = cmd & SIXP_CHN_MASK;
925 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */
926
927 /* RX and DCD flags can only be set in the same prio command,
928 if the DCD flag has been set without the RX flag in the previous
929 prio command. If DCD has not been set before, something in the
930 transmission has gone wrong. In this case, RX and DCD are
931 cleared in order to prevent the decode_data routine from
932 reading further data that might be corrupt. */
933
934 if (((sp->status & SIXP_DCD_MASK) == 0) &&
935 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) {
936 if (sp->status != 1)
937 printk(KERN_DEBUG "6pack: protocol violation\n");
938 else
939 sp->status = 0;
940 cmd &= !SIXP_RX_DCD_MASK;
941 }
942 sp->status = cmd & SIXP_PRIO_DATA_MASK;
943 } else { /* output watchdog char if idle */
944 if ((sp->status2 != 0) && (sp->duplex == 1)) {
945 sp->led_state = 0x70;
946 sp->tty->driver->write(sp->tty, &sp->led_state, 1);
947 sp->tx_enable = 1;
948 actual = sp->tty->driver->write(sp->tty, sp->xbuff, sp->status2);
949 sp->xleft -= actual;
950 sp->xhead += actual;
951 sp->led_state = 0x60;
952 sp->status2 = 0;
953
954 }
955 }
956
957 /* needed to trigger the TNC watchdog */
958 sp->tty->driver->write(sp->tty, &sp->led_state, 1);
959
960 /* if the state byte has been received, the TNC is present,
961 so the resync timer can be reset. */
962
963 if (sp->tnc_state == TNC_IN_SYNC) {
964 del_timer(&sp->resync_t);
965 sp->resync_t.data = (unsigned long) sp;
966 sp->resync_t.function = resync_tnc;
967 sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT;
968 add_timer(&sp->resync_t);
969 }
970
971 sp->status1 = cmd & SIXP_PRIO_DATA_MASK;
972}
973
974/* identify and execute a standard 6pack command byte */
975
976static void decode_std_command(struct sixpack *sp, unsigned char cmd)
977{
978 unsigned char checksum = 0, rest = 0, channel;
979 short i;
980
981 channel = cmd & SIXP_CHN_MASK;
982 switch (cmd & SIXP_CMD_MASK) { /* normal command */
983 case SIXP_SEOF:
984 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) {
985 if ((sp->status & SIXP_RX_DCD_MASK) ==
986 SIXP_RX_DCD_MASK) {
987 sp->led_state = 0x68;
988 sp->tty->driver->write(sp->tty, &sp->led_state, 1);
989 }
990 } else {
991 sp->led_state = 0x60;
992 /* fill trailing bytes with zeroes */
993 sp->tty->driver->write(sp->tty, &sp->led_state, 1);
994 rest = sp->rx_count;
995 if (rest != 0)
996 for (i = rest; i <= 3; i++)
997 decode_data(sp, 0);
998 if (rest == 2)
999 sp->rx_count_cooked -= 2;
1000 else if (rest == 3)
1001 sp->rx_count_cooked -= 1;
1002 for (i = 0; i < sp->rx_count_cooked; i++)
1003 checksum += sp->cooked_buf[i];
1004 if (checksum != SIXP_CHKSUM) {
1005 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum);
1006 } else {
1007 sp->rcount = sp->rx_count_cooked-2;
1008 sp_bump(sp, 0);
1009 }
1010 sp->rx_count_cooked = 0;
1011 }
1012 break;
1013 case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n");
1014 break;
1015 case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n");
1016 break;
1017 case SIXP_RX_BUF_OVL:
1018 printk(KERN_DEBUG "6pack: RX buffer overflow\n");
1019 }
1020}
1021
1022/* decode a 6pack packet */
1023
1024static void
1025sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count)
1026{
1027 unsigned char inbyte;
1028 int count1;
1029
1030 for (count1 = 0; count1 < count; count1++) {
1031 inbyte = pre_rbuff[count1];
1032 if (inbyte == SIXP_FOUND_TNC) {
1033 tnc_set_sync_state(sp, TNC_IN_SYNC);
1034 del_timer(&sp->resync_t);
1035 }
1036 if ((inbyte & SIXP_PRIO_CMD_MASK) != 0)
1037 decode_prio_command(sp, inbyte);
1038 else if ((inbyte & SIXP_STD_CMD_MASK) != 0)
1039 decode_std_command(sp, inbyte);
1040 else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)
1041 decode_data(sp, inbyte);
1042 }
1043}
1044
1045MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>");
1046MODULE_DESCRIPTION("6pack driver for AX.25");
1047MODULE_LICENSE("GPL");
1048MODULE_ALIAS_LDISC(N_6PACK);
1049
1050module_init(sixpack_init_driver);
1051module_exit(sixpack_exit_driver);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-17 13:49:13 -0500