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1/*
2 * Things to sort out:
3 *
4 * o tbusy handling
5 * o allow users to set the parameters
6 * o sync/async switching ?
7 *
8 * Note: This does _not_ implement CCITT X.25 asynchronous framing
9 * recommendations. Its primarily for testing purposes. If you wanted
10 * to do CCITT then in theory all you need is to nick the HDLC async
11 * checksum routines from ppp.c
12 * Changes:
13 *
14 * 2000-10-29 Henner Eisen lapb_data_indication() return status.
15 */
16
17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/module.h>
20
21#include <linux/uaccess.h>
22#include <linux/bitops.h>
23#include <linux/string.h>
24#include <linux/mm.h>
25#include <linux/interrupt.h>
26#include <linux/in.h>
27#include <linux/tty.h>
28#include <linux/errno.h>
29#include <linux/netdevice.h>
30#include <linux/etherdevice.h>
31#include <linux/skbuff.h>
32#include <linux/if_arp.h>
33#include <linux/lapb.h>
34#include <linux/init.h>
35#include <linux/rtnetlink.h>
36#include <linux/compat.h>
37#include <linux/slab.h>
38#include <net/x25device.h>
39#include "x25_asy.h"
40
41static struct net_device **x25_asy_devs;
42static int x25_asy_maxdev = SL_NRUNIT;
43
44module_param(x25_asy_maxdev, int, 0);
45MODULE_LICENSE("GPL");
46
47static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
48static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
49static void x25_asy_setup(struct net_device *dev);
50
51/* Find a free X.25 channel, and link in this `tty' line. */
52static struct x25_asy *x25_asy_alloc(void)
53{
54 struct net_device *dev = NULL;
55 struct x25_asy *sl;
56 int i;
57
58 if (x25_asy_devs == NULL)
59 return NULL; /* Master array missing ! */
60
61 for (i = 0; i < x25_asy_maxdev; i++) {
62 dev = x25_asy_devs[i];
63
64 /* Not allocated ? */
65 if (dev == NULL)
66 break;
67
68 sl = netdev_priv(dev);
69 /* Not in use ? */
70 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
71 return sl;
72 }
73
74
75 /* Sorry, too many, all slots in use */
76 if (i >= x25_asy_maxdev)
77 return NULL;
78
79 /* If no channels are available, allocate one */
80 if (!dev) {
81 char name[IFNAMSIZ];
82 sprintf(name, "x25asy%d", i);
83
84 dev = alloc_netdev(sizeof(struct x25_asy),
85 name, x25_asy_setup);
86 if (!dev)
87 return NULL;
88
89 /* Initialize channel control data */
90 sl = netdev_priv(dev);
91 dev->base_addr = i;
92
93 /* register device so that it can be ifconfig'ed */
94 if (register_netdev(dev) == 0) {
95 /* (Re-)Set the INUSE bit. Very Important! */
96 set_bit(SLF_INUSE, &sl->flags);
97 x25_asy_devs[i] = dev;
98 return sl;
99 } else {
100 pr_warn("%s(): register_netdev() failure\n", __func__);
101 free_netdev(dev);
102 }
103 }
104 return NULL;
105}
106
107
108/* Free an X.25 channel. */
109static void x25_asy_free(struct x25_asy *sl)
110{
111 /* Free all X.25 frame buffers. */
112 kfree(sl->rbuff);
113 sl->rbuff = NULL;
114 kfree(sl->xbuff);
115 sl->xbuff = NULL;
116
117 if (!test_and_clear_bit(SLF_INUSE, &sl->flags))
118 netdev_err(sl->dev, "x25_asy_free for already free unit\n");
119}
120
121static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
122{
123 struct x25_asy *sl = netdev_priv(dev);
124 unsigned char *xbuff, *rbuff;
125 int len = 2 * newmtu;
126
127 xbuff = kmalloc(len + 4, GFP_ATOMIC);
128 rbuff = kmalloc(len + 4, GFP_ATOMIC);
129
130 if (xbuff == NULL || rbuff == NULL) {
131 kfree(xbuff);
132 kfree(rbuff);
133 return -ENOMEM;
134 }
135
136 spin_lock_bh(&sl->lock);
137 xbuff = xchg(&sl->xbuff, xbuff);
138 if (sl->xleft) {
139 if (sl->xleft <= len) {
140 memcpy(sl->xbuff, sl->xhead, sl->xleft);
141 } else {
142 sl->xleft = 0;
143 dev->stats.tx_dropped++;
144 }
145 }
146 sl->xhead = sl->xbuff;
147
148 rbuff = xchg(&sl->rbuff, rbuff);
149 if (sl->rcount) {
150 if (sl->rcount <= len) {
151 memcpy(sl->rbuff, rbuff, sl->rcount);
152 } else {
153 sl->rcount = 0;
154 dev->stats.rx_over_errors++;
155 set_bit(SLF_ERROR, &sl->flags);
156 }
157 }
158
159 dev->mtu = newmtu;
160 sl->buffsize = len;
161
162 spin_unlock_bh(&sl->lock);
163
164 kfree(xbuff);
165 kfree(rbuff);
166 return 0;
167}
168
169
170/* Set the "sending" flag. This must be atomic, hence the ASM. */
171
172static inline void x25_asy_lock(struct x25_asy *sl)
173{
174 netif_stop_queue(sl->dev);
175}
176
177
178/* Clear the "sending" flag. This must be atomic, hence the ASM. */
179
180static inline void x25_asy_unlock(struct x25_asy *sl)
181{
182 netif_wake_queue(sl->dev);
183}
184
185/* Send one completely decapsulated IP datagram to the IP layer. */
186
187static void x25_asy_bump(struct x25_asy *sl)
188{
189 struct net_device *dev = sl->dev;
190 struct sk_buff *skb;
191 int count;
192 int err;
193
194 count = sl->rcount;
195 dev->stats.rx_bytes += count;
196
197 skb = dev_alloc_skb(count+1);
198 if (skb == NULL) {
199 netdev_warn(sl->dev, "memory squeeze, dropping packet\n");
200 dev->stats.rx_dropped++;
201 return;
202 }
203 skb_push(skb, 1); /* LAPB internal control */
204 memcpy(skb_put(skb, count), sl->rbuff, count);
205 skb->protocol = x25_type_trans(skb, sl->dev);
206 err = lapb_data_received(skb->dev, skb);
207 if (err != LAPB_OK) {
208 kfree_skb(skb);
209 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
210 } else {
211 netif_rx(skb);
212 dev->stats.rx_packets++;
213 }
214}
215
216/* Encapsulate one IP datagram and stuff into a TTY queue. */
217static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
218{
219 unsigned char *p;
220 int actual, count, mtu = sl->dev->mtu;
221
222 if (len > mtu) {
223 /* Sigh, shouldn't occur BUT ... */
224 len = mtu;
225 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
226 sl->dev->name);
227 sl->dev->stats.tx_dropped++;
228 x25_asy_unlock(sl);
229 return;
230 }
231
232 p = icp;
233 count = x25_asy_esc(p, sl->xbuff, len);
234
235 /* Order of next two lines is *very* important.
236 * When we are sending a little amount of data,
237 * the transfer may be completed inside driver.write()
238 * routine, because it's running with interrupts enabled.
239 * In this case we *never* got WRITE_WAKEUP event,
240 * if we did not request it before write operation.
241 * 14 Oct 1994 Dmitry Gorodchanin.
242 */
243 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
244 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
245 sl->xleft = count - actual;
246 sl->xhead = sl->xbuff + actual;
247 /* VSV */
248 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
249}
250
251/*
252 * Called by the driver when there's room for more data. If we have
253 * more packets to send, we send them here.
254 */
255static void x25_asy_write_wakeup(struct tty_struct *tty)
256{
257 int actual;
258 struct x25_asy *sl = tty->disc_data;
259
260 /* First make sure we're connected. */
261 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
262 return;
263
264 if (sl->xleft <= 0) {
265 /* Now serial buffer is almost free & we can start
266 * transmission of another packet */
267 sl->dev->stats.tx_packets++;
268 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
269 x25_asy_unlock(sl);
270 return;
271 }
272
273 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
274 sl->xleft -= actual;
275 sl->xhead += actual;
276}
277
278static void x25_asy_timeout(struct net_device *dev)
279{
280 struct x25_asy *sl = netdev_priv(dev);
281
282 spin_lock(&sl->lock);
283 if (netif_queue_stopped(dev)) {
284 /* May be we must check transmitter timeout here ?
285 * 14 Oct 1994 Dmitry Gorodchanin.
286 */
287 netdev_warn(dev, "transmit timed out, %s?\n",
288 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
289 "bad line quality" : "driver error");
290 sl->xleft = 0;
291 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
292 x25_asy_unlock(sl);
293 }
294 spin_unlock(&sl->lock);
295}
296
297/* Encapsulate an IP datagram and kick it into a TTY queue. */
298
299static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
300 struct net_device *dev)
301{
302 struct x25_asy *sl = netdev_priv(dev);
303 int err;
304
305 if (!netif_running(sl->dev)) {
306 netdev_err(dev, "xmit call when iface is down\n");
307 kfree_skb(skb);
308 return NETDEV_TX_OK;
309 }
310
311 switch (skb->data[0]) {
312 case X25_IFACE_DATA:
313 break;
314 case X25_IFACE_CONNECT: /* Connection request .. do nothing */
315 err = lapb_connect_request(dev);
316 if (err != LAPB_OK)
317 netdev_err(dev, "lapb_connect_request error: %d\n",
318 err);
319 kfree_skb(skb);
320 return NETDEV_TX_OK;
321 case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
322 err = lapb_disconnect_request(dev);
323 if (err != LAPB_OK)
324 netdev_err(dev, "lapb_disconnect_request error: %d\n",
325 err);
326 default:
327 kfree_skb(skb);
328 return NETDEV_TX_OK;
329 }
330 skb_pull(skb, 1); /* Remove control byte */
331 /*
332 * If we are busy already- too bad. We ought to be able
333 * to queue things at this point, to allow for a little
334 * frame buffer. Oh well...
335 * -----------------------------------------------------
336 * I hate queues in X.25 driver. May be it's efficient,
337 * but for me latency is more important. ;)
338 * So, no queues !
339 * 14 Oct 1994 Dmitry Gorodchanin.
340 */
341
342 err = lapb_data_request(dev, skb);
343 if (err != LAPB_OK) {
344 netdev_err(dev, "lapb_data_request error: %d\n", err);
345 kfree_skb(skb);
346 return NETDEV_TX_OK;
347 }
348 return NETDEV_TX_OK;
349}
350
351
352/*
353 * LAPB interface boilerplate
354 */
355
356/*
357 * Called when I frame data arrives. We did the work above - throw it
358 * at the net layer.
359 */
360
361static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
362{
363 return netif_rx(skb);
364}
365
366/*
367 * Data has emerged from the LAPB protocol machine. We don't handle
368 * busy cases too well. Its tricky to see how to do this nicely -
369 * perhaps lapb should allow us to bounce this ?
370 */
371
372static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
373{
374 struct x25_asy *sl = netdev_priv(dev);
375
376 spin_lock(&sl->lock);
377 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
378 spin_unlock(&sl->lock);
379 netdev_err(dev, "tbusy drop\n");
380 kfree_skb(skb);
381 return;
382 }
383 /* We were not busy, so we are now... :-) */
384 if (skb != NULL) {
385 x25_asy_lock(sl);
386 dev->stats.tx_bytes += skb->len;
387 x25_asy_encaps(sl, skb->data, skb->len);
388 dev_kfree_skb(skb);
389 }
390 spin_unlock(&sl->lock);
391}
392
393/*
394 * LAPB connection establish/down information.
395 */
396
397static void x25_asy_connected(struct net_device *dev, int reason)
398{
399 struct x25_asy *sl = netdev_priv(dev);
400 struct sk_buff *skb;
401 unsigned char *ptr;
402
403 skb = dev_alloc_skb(1);
404 if (skb == NULL) {
405 netdev_err(dev, "out of memory\n");
406 return;
407 }
408
409 ptr = skb_put(skb, 1);
410 *ptr = X25_IFACE_CONNECT;
411
412 skb->protocol = x25_type_trans(skb, sl->dev);
413 netif_rx(skb);
414}
415
416static void x25_asy_disconnected(struct net_device *dev, int reason)
417{
418 struct x25_asy *sl = netdev_priv(dev);
419 struct sk_buff *skb;
420 unsigned char *ptr;
421
422 skb = dev_alloc_skb(1);
423 if (skb == NULL) {
424 netdev_err(dev, "out of memory\n");
425 return;
426 }
427
428 ptr = skb_put(skb, 1);
429 *ptr = X25_IFACE_DISCONNECT;
430
431 skb->protocol = x25_type_trans(skb, sl->dev);
432 netif_rx(skb);
433}
434
435static const struct lapb_register_struct x25_asy_callbacks = {
436 .connect_confirmation = x25_asy_connected,
437 .connect_indication = x25_asy_connected,
438 .disconnect_confirmation = x25_asy_disconnected,
439 .disconnect_indication = x25_asy_disconnected,
440 .data_indication = x25_asy_data_indication,
441 .data_transmit = x25_asy_data_transmit,
442};
443
444
445/* Open the low-level part of the X.25 channel. Easy! */
446static int x25_asy_open(struct net_device *dev)
447{
448 struct x25_asy *sl = netdev_priv(dev);
449 unsigned long len;
450 int err;
451
452 if (sl->tty == NULL)
453 return -ENODEV;
454
455 /*
456 * Allocate the X.25 frame buffers:
457 *
458 * rbuff Receive buffer.
459 * xbuff Transmit buffer.
460 */
461
462 len = dev->mtu * 2;
463
464 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
465 if (sl->rbuff == NULL)
466 goto norbuff;
467 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
468 if (sl->xbuff == NULL)
469 goto noxbuff;
470
471 sl->buffsize = len;
472 sl->rcount = 0;
473 sl->xleft = 0;
474 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
475
476 netif_start_queue(dev);
477
478 /*
479 * Now attach LAPB
480 */
481 err = lapb_register(dev, &x25_asy_callbacks);
482 if (err == LAPB_OK)
483 return 0;
484
485 /* Cleanup */
486 kfree(sl->xbuff);
487noxbuff:
488 kfree(sl->rbuff);
489norbuff:
490 return -ENOMEM;
491}
492
493
494/* Close the low-level part of the X.25 channel. Easy! */
495static int x25_asy_close(struct net_device *dev)
496{
497 struct x25_asy *sl = netdev_priv(dev);
498
499 spin_lock(&sl->lock);
500 if (sl->tty)
501 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
502
503 netif_stop_queue(dev);
504 sl->rcount = 0;
505 sl->xleft = 0;
506 spin_unlock(&sl->lock);
507 return 0;
508}
509
510/*
511 * Handle the 'receiver data ready' interrupt.
512 * This function is called by the 'tty_io' module in the kernel when
513 * a block of X.25 data has been received, which can now be decapsulated
514 * and sent on to some IP layer for further processing.
515 */
516
517static void x25_asy_receive_buf(struct tty_struct *tty,
518 const unsigned char *cp, char *fp, int count)
519{
520 struct x25_asy *sl = tty->disc_data;
521
522 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
523 return;
524
525
526 /* Read the characters out of the buffer */
527 while (count--) {
528 if (fp && *fp++) {
529 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
530 sl->dev->stats.rx_errors++;
531 cp++;
532 continue;
533 }
534 x25_asy_unesc(sl, *cp++);
535 }
536}
537
538/*
539 * Open the high-level part of the X.25 channel.
540 * This function is called by the TTY module when the
541 * X.25 line discipline is called for. Because we are
542 * sure the tty line exists, we only have to link it to
543 * a free X.25 channel...
544 */
545
546static int x25_asy_open_tty(struct tty_struct *tty)
547{
548 struct x25_asy *sl = tty->disc_data;
549 int err;
550
551 if (tty->ops->write == NULL)
552 return -EOPNOTSUPP;
553
554 /* First make sure we're not already connected. */
555 if (sl && sl->magic == X25_ASY_MAGIC)
556 return -EEXIST;
557
558 /* OK. Find a free X.25 channel to use. */
559 sl = x25_asy_alloc();
560 if (sl == NULL)
561 return -ENFILE;
562
563 sl->tty = tty;
564 tty->disc_data = sl;
565 tty->receive_room = 65536;
566 tty_driver_flush_buffer(tty);
567 tty_ldisc_flush(tty);
568
569 /* Restore default settings */
570 sl->dev->type = ARPHRD_X25;
571
572 /* Perform the low-level X.25 async init */
573 err = x25_asy_open(sl->dev);
574 if (err)
575 return err;
576 /* Done. We have linked the TTY line to a channel. */
577 return 0;
578}
579
580
581/*
582 * Close down an X.25 channel.
583 * This means flushing out any pending queues, and then restoring the
584 * TTY line discipline to what it was before it got hooked to X.25
585 * (which usually is TTY again).
586 */
587static void x25_asy_close_tty(struct tty_struct *tty)
588{
589 struct x25_asy *sl = tty->disc_data;
590 int err;
591
592 /* First make sure we're connected. */
593 if (!sl || sl->magic != X25_ASY_MAGIC)
594 return;
595
596 rtnl_lock();
597 if (sl->dev->flags & IFF_UP)
598 dev_close(sl->dev);
599 rtnl_unlock();
600
601 err = lapb_unregister(sl->dev);
602 if (err != LAPB_OK)
603 pr_err("x25_asy_close: lapb_unregister error: %d\n",
604 err);
605
606 tty->disc_data = NULL;
607 sl->tty = NULL;
608 x25_asy_free(sl);
609}
610
611 /************************************************************************
612 * STANDARD X.25 ENCAPSULATION *
613 ************************************************************************/
614
615static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
616{
617 unsigned char *ptr = d;
618 unsigned char c;
619
620 /*
621 * Send an initial END character to flush out any
622 * data that may have accumulated in the receiver
623 * due to line noise.
624 */
625
626 *ptr++ = X25_END; /* Send 10111110 bit seq */
627
628 /*
629 * For each byte in the packet, send the appropriate
630 * character sequence, according to the X.25 protocol.
631 */
632
633 while (len-- > 0) {
634 switch (c = *s++) {
635 case X25_END:
636 *ptr++ = X25_ESC;
637 *ptr++ = X25_ESCAPE(X25_END);
638 break;
639 case X25_ESC:
640 *ptr++ = X25_ESC;
641 *ptr++ = X25_ESCAPE(X25_ESC);
642 break;
643 default:
644 *ptr++ = c;
645 break;
646 }
647 }
648 *ptr++ = X25_END;
649 return ptr - d;
650}
651
652static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
653{
654
655 switch (s) {
656 case X25_END:
657 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
658 sl->rcount > 2)
659 x25_asy_bump(sl);
660 clear_bit(SLF_ESCAPE, &sl->flags);
661 sl->rcount = 0;
662 return;
663 case X25_ESC:
664 set_bit(SLF_ESCAPE, &sl->flags);
665 return;
666 case X25_ESCAPE(X25_ESC):
667 case X25_ESCAPE(X25_END):
668 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
669 s = X25_UNESCAPE(s);
670 break;
671 }
672 if (!test_bit(SLF_ERROR, &sl->flags)) {
673 if (sl->rcount < sl->buffsize) {
674 sl->rbuff[sl->rcount++] = s;
675 return;
676 }
677 sl->dev->stats.rx_over_errors++;
678 set_bit(SLF_ERROR, &sl->flags);
679 }
680}
681
682
683/* Perform I/O control on an active X.25 channel. */
684static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
685 unsigned int cmd, unsigned long arg)
686{
687 struct x25_asy *sl = tty->disc_data;
688
689 /* First make sure we're connected. */
690 if (!sl || sl->magic != X25_ASY_MAGIC)
691 return -EINVAL;
692
693 switch (cmd) {
694 case SIOCGIFNAME:
695 if (copy_to_user((void __user *)arg, sl->dev->name,
696 strlen(sl->dev->name) + 1))
697 return -EFAULT;
698 return 0;
699 case SIOCSIFHWADDR:
700 return -EINVAL;
701 default:
702 return tty_mode_ioctl(tty, file, cmd, arg);
703 }
704}
705
706#ifdef CONFIG_COMPAT
707static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
708 unsigned int cmd, unsigned long arg)
709{
710 switch (cmd) {
711 case SIOCGIFNAME:
712 case SIOCSIFHWADDR:
713 return x25_asy_ioctl(tty, file, cmd,
714 (unsigned long)compat_ptr(arg));
715 }
716
717 return -ENOIOCTLCMD;
718}
719#endif
720
721static int x25_asy_open_dev(struct net_device *dev)
722{
723 struct x25_asy *sl = netdev_priv(dev);
724 if (sl->tty == NULL)
725 return -ENODEV;
726 return 0;
727}
728
729static const struct net_device_ops x25_asy_netdev_ops = {
730 .ndo_open = x25_asy_open_dev,
731 .ndo_stop = x25_asy_close,
732 .ndo_start_xmit = x25_asy_xmit,
733 .ndo_tx_timeout = x25_asy_timeout,
734 .ndo_change_mtu = x25_asy_change_mtu,
735};
736
737/* Initialise the X.25 driver. Called by the device init code */
738static void x25_asy_setup(struct net_device *dev)
739{
740 struct x25_asy *sl = netdev_priv(dev);
741
742 sl->magic = X25_ASY_MAGIC;
743 sl->dev = dev;
744 spin_lock_init(&sl->lock);
745 set_bit(SLF_INUSE, &sl->flags);
746
747 /*
748 * Finish setting up the DEVICE info.
749 */
750
751 dev->mtu = SL_MTU;
752 dev->netdev_ops = &x25_asy_netdev_ops;
753 dev->watchdog_timeo = HZ*20;
754 dev->hard_header_len = 0;
755 dev->addr_len = 0;
756 dev->type = ARPHRD_X25;
757 dev->tx_queue_len = 10;
758
759 /* New-style flags. */
760 dev->flags = IFF_NOARP;
761}
762
763static struct tty_ldisc_ops x25_ldisc = {
764 .owner = THIS_MODULE,
765 .magic = TTY_LDISC_MAGIC,
766 .name = "X.25",
767 .open = x25_asy_open_tty,
768 .close = x25_asy_close_tty,
769 .ioctl = x25_asy_ioctl,
770#ifdef CONFIG_COMPAT
771 .compat_ioctl = x25_asy_compat_ioctl,
772#endif
773 .receive_buf = x25_asy_receive_buf,
774 .write_wakeup = x25_asy_write_wakeup,
775};
776
777static int __init init_x25_asy(void)
778{
779 if (x25_asy_maxdev < 4)
780 x25_asy_maxdev = 4; /* Sanity */
781
782 pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n",
783 x25_asy_maxdev);
784
785 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
786 GFP_KERNEL);
787 if (!x25_asy_devs)
788 return -ENOMEM;
789
790 return tty_register_ldisc(N_X25, &x25_ldisc);
791}
792
793
794static void __exit exit_x25_asy(void)
795{
796 struct net_device *dev;
797 int i;
798
799 for (i = 0; i < x25_asy_maxdev; i++) {
800 dev = x25_asy_devs[i];
801 if (dev) {
802 struct x25_asy *sl = netdev_priv(dev);
803
804 spin_lock_bh(&sl->lock);
805 if (sl->tty)
806 tty_hangup(sl->tty);
807
808 spin_unlock_bh(&sl->lock);
809 /*
810 * VSV = if dev->start==0, then device
811 * unregistered while close proc.
812 */
813 unregister_netdev(dev);
814 free_netdev(dev);
815 }
816 }
817
818 kfree(x25_asy_devs);
819 tty_unregister_ldisc(N_X25);
820}
821
822module_init(init_x25_asy);
823module_exit(exit_x25_asy);