1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Things to sort out:
4 *
5 * o tbusy handling
6 * o allow users to set the parameters
7 * o sync/async switching ?
8 *
9 * Note: This does _not_ implement CCITT X.25 asynchronous framing
10 * recommendations. Its primarily for testing purposes. If you wanted
11 * to do CCITT then in theory all you need is to nick the HDLC async
12 * checksum routines from ppp.c
13 * Changes:
14 *
15 * 2000-10-29 Henner Eisen lapb_data_indication() return status.
16 */
17
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20 #include <linux/module.h>
21
22 #include <linux/uaccess.h>
23 #include <linux/bitops.h>
24 #include <linux/string.h>
25 #include <linux/mm.h>
26 #include <linux/interrupt.h>
27 #include <linux/in.h>
28 #include <linux/tty.h>
29 #include <linux/errno.h>
30 #include <linux/netdevice.h>
31 #include <linux/etherdevice.h>
32 #include <linux/skbuff.h>
33 #include <linux/if_arp.h>
34 #include <linux/lapb.h>
35 #include <linux/init.h>
36 #include <linux/rtnetlink.h>
37 #include <linux/slab.h>
38 #include <net/x25device.h>
39 #include "x25_asy.h"
40
41 static struct net_device **x25_asy_devs;
42 static int x25_asy_maxdev = SL_NRUNIT;
43
44 module_param(x25_asy_maxdev, int, 0);
45 MODULE_LICENSE("GPL");
46
47 static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
48 static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
49 static void x25_asy_setup(struct net_device *dev);
50
51 /* Find a free X.25 channel, and link in this `tty' line. */
x25_asy_alloc(void)52 static 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), name,
85 NET_NAME_UNKNOWN, 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. */
x25_asy_free(struct x25_asy * sl)109 static 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
x25_asy_change_mtu(struct net_device * dev,int newmtu)121 static 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;
126
127 len = 2 * newmtu;
128 xbuff = kmalloc(len + 4, GFP_ATOMIC);
129 rbuff = kmalloc(len + 4, GFP_ATOMIC);
130
131 if (xbuff == NULL || rbuff == NULL) {
132 kfree(xbuff);
133 kfree(rbuff);
134 return -ENOMEM;
135 }
136
137 spin_lock_bh(&sl->lock);
138 xbuff = xchg(&sl->xbuff, xbuff);
139 if (sl->xleft) {
140 if (sl->xleft <= len) {
141 memcpy(sl->xbuff, sl->xhead, sl->xleft);
142 } else {
143 sl->xleft = 0;
144 dev->stats.tx_dropped++;
145 }
146 }
147 sl->xhead = sl->xbuff;
148
149 rbuff = xchg(&sl->rbuff, rbuff);
150 if (sl->rcount) {
151 if (sl->rcount <= len) {
152 memcpy(sl->rbuff, rbuff, sl->rcount);
153 } else {
154 sl->rcount = 0;
155 dev->stats.rx_over_errors++;
156 set_bit(SLF_ERROR, &sl->flags);
157 }
158 }
159
160 dev->mtu = newmtu;
161 sl->buffsize = len;
162
163 spin_unlock_bh(&sl->lock);
164
165 kfree(xbuff);
166 kfree(rbuff);
167 return 0;
168 }
169
170
171 /* Set the "sending" flag. This must be atomic, hence the ASM. */
172
x25_asy_lock(struct x25_asy * sl)173 static inline void x25_asy_lock(struct x25_asy *sl)
174 {
175 netif_stop_queue(sl->dev);
176 }
177
178
179 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
180
x25_asy_unlock(struct x25_asy * sl)181 static inline void x25_asy_unlock(struct x25_asy *sl)
182 {
183 netif_wake_queue(sl->dev);
184 }
185
186 /* Send one completely decapsulated IP datagram to the IP layer. */
187
x25_asy_bump(struct x25_asy * sl)188 static void x25_asy_bump(struct x25_asy *sl)
189 {
190 struct net_device *dev = sl->dev;
191 struct sk_buff *skb;
192 int count;
193 int err;
194
195 count = sl->rcount;
196 dev->stats.rx_bytes += count;
197
198 skb = dev_alloc_skb(count+1);
199 if (skb == NULL) {
200 netdev_warn(sl->dev, "memory squeeze, dropping packet\n");
201 dev->stats.rx_dropped++;
202 return;
203 }
204 skb_push(skb, 1); /* LAPB internal control */
205 skb_put_data(skb, sl->rbuff, count);
206 skb->protocol = x25_type_trans(skb, sl->dev);
207 err = lapb_data_received(skb->dev, skb);
208 if (err != LAPB_OK) {
209 kfree_skb(skb);
210 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
211 } else {
212 netif_rx(skb);
213 dev->stats.rx_packets++;
214 }
215 }
216
217 /* Encapsulate one IP datagram and stuff into a TTY queue. */
x25_asy_encaps(struct x25_asy * sl,unsigned char * icp,int len)218 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
219 {
220 unsigned char *p;
221 int actual, count, mtu = sl->dev->mtu;
222
223 if (len > mtu) {
224 /* Sigh, shouldn't occur BUT ... */
225 len = mtu;
226 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
227 sl->dev->name);
228 sl->dev->stats.tx_dropped++;
229 x25_asy_unlock(sl);
230 return;
231 }
232
233 p = icp;
234 count = x25_asy_esc(p, sl->xbuff, len);
235
236 /* Order of next two lines is *very* important.
237 * When we are sending a little amount of data,
238 * the transfer may be completed inside driver.write()
239 * routine, because it's running with interrupts enabled.
240 * In this case we *never* got WRITE_WAKEUP event,
241 * if we did not request it before write operation.
242 * 14 Oct 1994 Dmitry Gorodchanin.
243 */
244 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
245 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
246 sl->xleft = count - actual;
247 sl->xhead = sl->xbuff + actual;
248 /* VSV */
249 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
250 }
251
252 /*
253 * Called by the driver when there's room for more data. If we have
254 * more packets to send, we send them here.
255 */
x25_asy_write_wakeup(struct tty_struct * tty)256 static void x25_asy_write_wakeup(struct tty_struct *tty)
257 {
258 int actual;
259 struct x25_asy *sl = tty->disc_data;
260
261 /* First make sure we're connected. */
262 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
263 return;
264
265 if (sl->xleft <= 0) {
266 /* Now serial buffer is almost free & we can start
267 * transmission of another packet */
268 sl->dev->stats.tx_packets++;
269 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
270 x25_asy_unlock(sl);
271 return;
272 }
273
274 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
275 sl->xleft -= actual;
276 sl->xhead += actual;
277 }
278
x25_asy_timeout(struct net_device * dev)279 static void x25_asy_timeout(struct net_device *dev)
280 {
281 struct x25_asy *sl = netdev_priv(dev);
282
283 spin_lock(&sl->lock);
284 if (netif_queue_stopped(dev)) {
285 /* May be we must check transmitter timeout here ?
286 * 14 Oct 1994 Dmitry Gorodchanin.
287 */
288 netdev_warn(dev, "transmit timed out, %s?\n",
289 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
290 "bad line quality" : "driver error");
291 sl->xleft = 0;
292 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
293 x25_asy_unlock(sl);
294 }
295 spin_unlock(&sl->lock);
296 }
297
298 /* Encapsulate an IP datagram and kick it into a TTY queue. */
299
x25_asy_xmit(struct sk_buff * skb,struct net_device * dev)300 static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
301 struct net_device *dev)
302 {
303 struct x25_asy *sl = netdev_priv(dev);
304 int err;
305
306 if (!netif_running(sl->dev)) {
307 netdev_err(dev, "xmit call when iface is down\n");
308 kfree_skb(skb);
309 return NETDEV_TX_OK;
310 }
311
312 switch (skb->data[0]) {
313 case X25_IFACE_DATA:
314 break;
315 case X25_IFACE_CONNECT: /* Connection request .. do nothing */
316 err = lapb_connect_request(dev);
317 if (err != LAPB_OK)
318 netdev_err(dev, "lapb_connect_request error: %d\n",
319 err);
320 kfree_skb(skb);
321 return NETDEV_TX_OK;
322 case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
323 err = lapb_disconnect_request(dev);
324 if (err != LAPB_OK)
325 netdev_err(dev, "lapb_disconnect_request error: %d\n",
326 err);
327 /* fall through */
328 default:
329 kfree_skb(skb);
330 return NETDEV_TX_OK;
331 }
332 skb_pull(skb, 1); /* Remove control byte */
333 /*
334 * If we are busy already- too bad. We ought to be able
335 * to queue things at this point, to allow for a little
336 * frame buffer. Oh well...
337 * -----------------------------------------------------
338 * I hate queues in X.25 driver. May be it's efficient,
339 * but for me latency is more important. ;)
340 * So, no queues !
341 * 14 Oct 1994 Dmitry Gorodchanin.
342 */
343
344 err = lapb_data_request(dev, skb);
345 if (err != LAPB_OK) {
346 netdev_err(dev, "lapb_data_request error: %d\n", err);
347 kfree_skb(skb);
348 return NETDEV_TX_OK;
349 }
350 return NETDEV_TX_OK;
351 }
352
353
354 /*
355 * LAPB interface boilerplate
356 */
357
358 /*
359 * Called when I frame data arrives. We did the work above - throw it
360 * at the net layer.
361 */
362
x25_asy_data_indication(struct net_device * dev,struct sk_buff * skb)363 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
364 {
365 return netif_rx(skb);
366 }
367
368 /*
369 * Data has emerged from the LAPB protocol machine. We don't handle
370 * busy cases too well. Its tricky to see how to do this nicely -
371 * perhaps lapb should allow us to bounce this ?
372 */
373
x25_asy_data_transmit(struct net_device * dev,struct sk_buff * skb)374 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
375 {
376 struct x25_asy *sl = netdev_priv(dev);
377
378 spin_lock(&sl->lock);
379 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
380 spin_unlock(&sl->lock);
381 netdev_err(dev, "tbusy drop\n");
382 kfree_skb(skb);
383 return;
384 }
385 /* We were not busy, so we are now... :-) */
386 if (skb != NULL) {
387 x25_asy_lock(sl);
388 dev->stats.tx_bytes += skb->len;
389 x25_asy_encaps(sl, skb->data, skb->len);
390 dev_kfree_skb(skb);
391 }
392 spin_unlock(&sl->lock);
393 }
394
395 /*
396 * LAPB connection establish/down information.
397 */
398
x25_asy_connected(struct net_device * dev,int reason)399 static void x25_asy_connected(struct net_device *dev, int reason)
400 {
401 struct x25_asy *sl = netdev_priv(dev);
402 struct sk_buff *skb;
403 unsigned char *ptr;
404
405 skb = dev_alloc_skb(1);
406 if (skb == NULL) {
407 netdev_err(dev, "out of memory\n");
408 return;
409 }
410
411 ptr = skb_put(skb, 1);
412 *ptr = X25_IFACE_CONNECT;
413
414 skb->protocol = x25_type_trans(skb, sl->dev);
415 netif_rx(skb);
416 }
417
x25_asy_disconnected(struct net_device * dev,int reason)418 static void x25_asy_disconnected(struct net_device *dev, int reason)
419 {
420 struct x25_asy *sl = netdev_priv(dev);
421 struct sk_buff *skb;
422 unsigned char *ptr;
423
424 skb = dev_alloc_skb(1);
425 if (skb == NULL) {
426 netdev_err(dev, "out of memory\n");
427 return;
428 }
429
430 ptr = skb_put(skb, 1);
431 *ptr = X25_IFACE_DISCONNECT;
432
433 skb->protocol = x25_type_trans(skb, sl->dev);
434 netif_rx(skb);
435 }
436
437 static const struct lapb_register_struct x25_asy_callbacks = {
438 .connect_confirmation = x25_asy_connected,
439 .connect_indication = x25_asy_connected,
440 .disconnect_confirmation = x25_asy_disconnected,
441 .disconnect_indication = x25_asy_disconnected,
442 .data_indication = x25_asy_data_indication,
443 .data_transmit = x25_asy_data_transmit,
444 };
445
446
447 /* Open the low-level part of the X.25 channel. Easy! */
x25_asy_open(struct net_device * dev)448 static int x25_asy_open(struct net_device *dev)
449 {
450 struct x25_asy *sl = netdev_priv(dev);
451 unsigned long len;
452 int err;
453
454 if (sl->tty == NULL)
455 return -ENODEV;
456
457 /*
458 * Allocate the X.25 frame buffers:
459 *
460 * rbuff Receive buffer.
461 * xbuff Transmit buffer.
462 */
463
464 len = dev->mtu * 2;
465
466 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
467 if (sl->rbuff == NULL)
468 goto norbuff;
469 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
470 if (sl->xbuff == NULL)
471 goto noxbuff;
472
473 sl->buffsize = len;
474 sl->rcount = 0;
475 sl->xleft = 0;
476 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
477
478 netif_start_queue(dev);
479
480 /*
481 * Now attach LAPB
482 */
483 err = lapb_register(dev, &x25_asy_callbacks);
484 if (err == LAPB_OK)
485 return 0;
486
487 /* Cleanup */
488 kfree(sl->xbuff);
489 sl->xbuff = NULL;
490 noxbuff:
491 kfree(sl->rbuff);
492 sl->rbuff = NULL;
493 norbuff:
494 return -ENOMEM;
495 }
496
497
498 /* Close the low-level part of the X.25 channel. Easy! */
x25_asy_close(struct net_device * dev)499 static int x25_asy_close(struct net_device *dev)
500 {
501 struct x25_asy *sl = netdev_priv(dev);
502
503 spin_lock(&sl->lock);
504 if (sl->tty)
505 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
506
507 netif_stop_queue(dev);
508 sl->rcount = 0;
509 sl->xleft = 0;
510 spin_unlock(&sl->lock);
511 return 0;
512 }
513
514 /*
515 * Handle the 'receiver data ready' interrupt.
516 * This function is called by the 'tty_io' module in the kernel when
517 * a block of X.25 data has been received, which can now be decapsulated
518 * and sent on to some IP layer for further processing.
519 */
520
x25_asy_receive_buf(struct tty_struct * tty,const unsigned char * cp,char * fp,int count)521 static void x25_asy_receive_buf(struct tty_struct *tty,
522 const unsigned char *cp, char *fp, int count)
523 {
524 struct x25_asy *sl = tty->disc_data;
525
526 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
527 return;
528
529
530 /* Read the characters out of the buffer */
531 while (count--) {
532 if (fp && *fp++) {
533 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
534 sl->dev->stats.rx_errors++;
535 cp++;
536 continue;
537 }
538 x25_asy_unesc(sl, *cp++);
539 }
540 }
541
542 /*
543 * Open the high-level part of the X.25 channel.
544 * This function is called by the TTY module when the
545 * X.25 line discipline is called for. Because we are
546 * sure the tty line exists, we only have to link it to
547 * a free X.25 channel...
548 */
549
x25_asy_open_tty(struct tty_struct * tty)550 static int x25_asy_open_tty(struct tty_struct *tty)
551 {
552 struct x25_asy *sl;
553 int err;
554
555 if (tty->ops->write == NULL)
556 return -EOPNOTSUPP;
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 x25_asy_free(sl);
576 return err;
577 }
578 /* Done. We have linked the TTY line to a channel. */
579 return 0;
580 }
581
582
583 /*
584 * Close down an X.25 channel.
585 * This means flushing out any pending queues, and then restoring the
586 * TTY line discipline to what it was before it got hooked to X.25
587 * (which usually is TTY again).
588 */
x25_asy_close_tty(struct tty_struct * tty)589 static void x25_asy_close_tty(struct tty_struct *tty)
590 {
591 struct x25_asy *sl = tty->disc_data;
592 int err;
593
594 /* First make sure we're connected. */
595 if (!sl || sl->magic != X25_ASY_MAGIC)
596 return;
597
598 rtnl_lock();
599 if (sl->dev->flags & IFF_UP)
600 dev_close(sl->dev);
601 rtnl_unlock();
602
603 err = lapb_unregister(sl->dev);
604 if (err != LAPB_OK)
605 pr_err("%s: lapb_unregister error: %d\n",
606 __func__, err);
607
608 tty->disc_data = NULL;
609 sl->tty = NULL;
610 x25_asy_free(sl);
611 }
612
613 /************************************************************************
614 * STANDARD X.25 ENCAPSULATION *
615 ************************************************************************/
616
x25_asy_esc(unsigned char * s,unsigned char * d,int len)617 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
618 {
619 unsigned char *ptr = d;
620 unsigned char c;
621
622 /*
623 * Send an initial END character to flush out any
624 * data that may have accumulated in the receiver
625 * due to line noise.
626 */
627
628 *ptr++ = X25_END; /* Send 10111110 bit seq */
629
630 /*
631 * For each byte in the packet, send the appropriate
632 * character sequence, according to the X.25 protocol.
633 */
634
635 while (len-- > 0) {
636 switch (c = *s++) {
637 case X25_END:
638 *ptr++ = X25_ESC;
639 *ptr++ = X25_ESCAPE(X25_END);
640 break;
641 case X25_ESC:
642 *ptr++ = X25_ESC;
643 *ptr++ = X25_ESCAPE(X25_ESC);
644 break;
645 default:
646 *ptr++ = c;
647 break;
648 }
649 }
650 *ptr++ = X25_END;
651 return ptr - d;
652 }
653
x25_asy_unesc(struct x25_asy * sl,unsigned char s)654 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
655 {
656
657 switch (s) {
658 case X25_END:
659 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
660 sl->rcount > 2)
661 x25_asy_bump(sl);
662 clear_bit(SLF_ESCAPE, &sl->flags);
663 sl->rcount = 0;
664 return;
665 case X25_ESC:
666 set_bit(SLF_ESCAPE, &sl->flags);
667 return;
668 case X25_ESCAPE(X25_ESC):
669 case X25_ESCAPE(X25_END):
670 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
671 s = X25_UNESCAPE(s);
672 break;
673 }
674 if (!test_bit(SLF_ERROR, &sl->flags)) {
675 if (sl->rcount < sl->buffsize) {
676 sl->rbuff[sl->rcount++] = s;
677 return;
678 }
679 sl->dev->stats.rx_over_errors++;
680 set_bit(SLF_ERROR, &sl->flags);
681 }
682 }
683
684
685 /* Perform I/O control on an active X.25 channel. */
x25_asy_ioctl(struct tty_struct * tty,struct file * file,unsigned int cmd,unsigned long arg)686 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
687 unsigned int cmd, unsigned long arg)
688 {
689 struct x25_asy *sl = tty->disc_data;
690
691 /* First make sure we're connected. */
692 if (!sl || sl->magic != X25_ASY_MAGIC)
693 return -EINVAL;
694
695 switch (cmd) {
696 case SIOCGIFNAME:
697 if (copy_to_user((void __user *)arg, sl->dev->name,
698 strlen(sl->dev->name) + 1))
699 return -EFAULT;
700 return 0;
701 case SIOCSIFHWADDR:
702 return -EINVAL;
703 default:
704 return tty_mode_ioctl(tty, file, cmd, arg);
705 }
706 }
707
x25_asy_open_dev(struct net_device * dev)708 static int x25_asy_open_dev(struct net_device *dev)
709 {
710 struct x25_asy *sl = netdev_priv(dev);
711 if (sl->tty == NULL)
712 return -ENODEV;
713 return 0;
714 }
715
716 static const struct net_device_ops x25_asy_netdev_ops = {
717 .ndo_open = x25_asy_open_dev,
718 .ndo_stop = x25_asy_close,
719 .ndo_start_xmit = x25_asy_xmit,
720 .ndo_tx_timeout = x25_asy_timeout,
721 .ndo_change_mtu = x25_asy_change_mtu,
722 };
723
724 /* Initialise the X.25 driver. Called by the device init code */
x25_asy_setup(struct net_device * dev)725 static void x25_asy_setup(struct net_device *dev)
726 {
727 struct x25_asy *sl = netdev_priv(dev);
728
729 sl->magic = X25_ASY_MAGIC;
730 sl->dev = dev;
731 spin_lock_init(&sl->lock);
732 set_bit(SLF_INUSE, &sl->flags);
733
734 /*
735 * Finish setting up the DEVICE info.
736 */
737
738 dev->mtu = SL_MTU;
739 dev->min_mtu = 0;
740 dev->max_mtu = 65534;
741 dev->netdev_ops = &x25_asy_netdev_ops;
742 dev->watchdog_timeo = HZ*20;
743 dev->hard_header_len = 0;
744 dev->addr_len = 0;
745 dev->type = ARPHRD_X25;
746 dev->tx_queue_len = 10;
747
748 /* New-style flags. */
749 dev->flags = IFF_NOARP;
750 }
751
752 static struct tty_ldisc_ops x25_ldisc = {
753 .owner = THIS_MODULE,
754 .magic = TTY_LDISC_MAGIC,
755 .name = "X.25",
756 .open = x25_asy_open_tty,
757 .close = x25_asy_close_tty,
758 .ioctl = x25_asy_ioctl,
759 .receive_buf = x25_asy_receive_buf,
760 .write_wakeup = x25_asy_write_wakeup,
761 };
762
init_x25_asy(void)763 static int __init init_x25_asy(void)
764 {
765 if (x25_asy_maxdev < 4)
766 x25_asy_maxdev = 4; /* Sanity */
767
768 pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n",
769 x25_asy_maxdev);
770
771 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
772 GFP_KERNEL);
773 if (!x25_asy_devs)
774 return -ENOMEM;
775
776 return tty_register_ldisc(N_X25, &x25_ldisc);
777 }
778
779
exit_x25_asy(void)780 static void __exit exit_x25_asy(void)
781 {
782 struct net_device *dev;
783 int i;
784
785 for (i = 0; i < x25_asy_maxdev; i++) {
786 dev = x25_asy_devs[i];
787 if (dev) {
788 struct x25_asy *sl = netdev_priv(dev);
789
790 spin_lock_bh(&sl->lock);
791 if (sl->tty)
792 tty_hangup(sl->tty);
793
794 spin_unlock_bh(&sl->lock);
795 /*
796 * VSV = if dev->start==0, then device
797 * unregistered while close proc.
798 */
799 unregister_netdev(dev);
800 free_netdev(dev);
801 }
802 }
803
804 kfree(x25_asy_devs);
805 tty_unregister_ldisc(N_X25);
806 }
807
808 module_init(init_x25_asy);
809 module_exit(exit_x25_asy);
810