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
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 default:
328 kfree_skb(skb);
329 return NETDEV_TX_OK;
330 }
331 skb_pull(skb, 1); /* Remove control byte */
332 /*
333 * If we are busy already- too bad. We ought to be able
334 * to queue things at this point, to allow for a little
335 * frame buffer. Oh well...
336 * -----------------------------------------------------
337 * I hate queues in X.25 driver. May be it's efficient,
338 * but for me latency is more important. ;)
339 * So, no queues !
340 * 14 Oct 1994 Dmitry Gorodchanin.
341 */
342
343 err = lapb_data_request(dev, skb);
344 if (err != LAPB_OK) {
345 netdev_err(dev, "lapb_data_request error: %d\n", err);
346 kfree_skb(skb);
347 return NETDEV_TX_OK;
348 }
349 return NETDEV_TX_OK;
350 }
351
352
353 /*
354 * LAPB interface boilerplate
355 */
356
357 /*
358 * Called when I frame data arrives. We did the work above - throw it
359 * at the net layer.
360 */
361
x25_asy_data_indication(struct net_device * dev,struct sk_buff * skb)362 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
363 {
364 return netif_rx(skb);
365 }
366
367 /*
368 * Data has emerged from the LAPB protocol machine. We don't handle
369 * busy cases too well. Its tricky to see how to do this nicely -
370 * perhaps lapb should allow us to bounce this ?
371 */
372
x25_asy_data_transmit(struct net_device * dev,struct sk_buff * skb)373 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
374 {
375 struct x25_asy *sl = netdev_priv(dev);
376
377 spin_lock(&sl->lock);
378 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
379 spin_unlock(&sl->lock);
380 netdev_err(dev, "tbusy drop\n");
381 kfree_skb(skb);
382 return;
383 }
384 /* We were not busy, so we are now... :-) */
385 if (skb != NULL) {
386 x25_asy_lock(sl);
387 dev->stats.tx_bytes += skb->len;
388 x25_asy_encaps(sl, skb->data, skb->len);
389 dev_kfree_skb(skb);
390 }
391 spin_unlock(&sl->lock);
392 }
393
394 /*
395 * LAPB connection establish/down information.
396 */
397
x25_asy_connected(struct net_device * dev,int reason)398 static void x25_asy_connected(struct net_device *dev, int reason)
399 {
400 struct x25_asy *sl = netdev_priv(dev);
401 struct sk_buff *skb;
402 unsigned char *ptr;
403
404 skb = dev_alloc_skb(1);
405 if (skb == NULL) {
406 netdev_err(dev, "out of memory\n");
407 return;
408 }
409
410 ptr = skb_put(skb, 1);
411 *ptr = X25_IFACE_CONNECT;
412
413 skb->protocol = x25_type_trans(skb, sl->dev);
414 netif_rx(skb);
415 }
416
x25_asy_disconnected(struct net_device * dev,int reason)417 static void x25_asy_disconnected(struct net_device *dev, int reason)
418 {
419 struct x25_asy *sl = netdev_priv(dev);
420 struct sk_buff *skb;
421 unsigned char *ptr;
422
423 skb = dev_alloc_skb(1);
424 if (skb == NULL) {
425 netdev_err(dev, "out of memory\n");
426 return;
427 }
428
429 ptr = skb_put(skb, 1);
430 *ptr = X25_IFACE_DISCONNECT;
431
432 skb->protocol = x25_type_trans(skb, sl->dev);
433 netif_rx(skb);
434 }
435
436 static const struct lapb_register_struct x25_asy_callbacks = {
437 .connect_confirmation = x25_asy_connected,
438 .connect_indication = x25_asy_connected,
439 .disconnect_confirmation = x25_asy_disconnected,
440 .disconnect_indication = x25_asy_disconnected,
441 .data_indication = x25_asy_data_indication,
442 .data_transmit = x25_asy_data_transmit,
443 };
444
445
446 /* Open the low-level part of the X.25 channel. Easy! */
x25_asy_open(struct net_device * dev)447 static int x25_asy_open(struct net_device *dev)
448 {
449 struct x25_asy *sl = netdev_priv(dev);
450 unsigned long len;
451 int err;
452
453 if (sl->tty == NULL)
454 return -ENODEV;
455
456 /*
457 * Allocate the X.25 frame buffers:
458 *
459 * rbuff Receive buffer.
460 * xbuff Transmit buffer.
461 */
462
463 len = dev->mtu * 2;
464
465 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
466 if (sl->rbuff == NULL)
467 goto norbuff;
468 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
469 if (sl->xbuff == NULL)
470 goto noxbuff;
471
472 sl->buffsize = len;
473 sl->rcount = 0;
474 sl->xleft = 0;
475 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
476
477 netif_start_queue(dev);
478
479 /*
480 * Now attach LAPB
481 */
482 err = lapb_register(dev, &x25_asy_callbacks);
483 if (err == LAPB_OK)
484 return 0;
485
486 /* Cleanup */
487 kfree(sl->xbuff);
488 sl->xbuff = NULL;
489 noxbuff:
490 kfree(sl->rbuff);
491 sl->rbuff = NULL;
492 norbuff:
493 return -ENOMEM;
494 }
495
496
497 /* Close the low-level part of the X.25 channel. Easy! */
x25_asy_close(struct net_device * dev)498 static int x25_asy_close(struct net_device *dev)
499 {
500 struct x25_asy *sl = netdev_priv(dev);
501
502 spin_lock(&sl->lock);
503 if (sl->tty)
504 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
505
506 netif_stop_queue(dev);
507 sl->rcount = 0;
508 sl->xleft = 0;
509 spin_unlock(&sl->lock);
510 return 0;
511 }
512
513 /*
514 * Handle the 'receiver data ready' interrupt.
515 * This function is called by the 'tty_io' module in the kernel when
516 * a block of X.25 data has been received, which can now be decapsulated
517 * and sent on to some IP layer for further processing.
518 */
519
x25_asy_receive_buf(struct tty_struct * tty,const unsigned char * cp,char * fp,int count)520 static void x25_asy_receive_buf(struct tty_struct *tty,
521 const unsigned char *cp, char *fp, int count)
522 {
523 struct x25_asy *sl = tty->disc_data;
524
525 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
526 return;
527
528
529 /* Read the characters out of the buffer */
530 while (count--) {
531 if (fp && *fp++) {
532 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
533 sl->dev->stats.rx_errors++;
534 cp++;
535 continue;
536 }
537 x25_asy_unesc(sl, *cp++);
538 }
539 }
540
541 /*
542 * Open the high-level part of the X.25 channel.
543 * This function is called by the TTY module when the
544 * X.25 line discipline is called for. Because we are
545 * sure the tty line exists, we only have to link it to
546 * a free X.25 channel...
547 */
548
x25_asy_open_tty(struct tty_struct * tty)549 static int x25_asy_open_tty(struct tty_struct *tty)
550 {
551 struct x25_asy *sl;
552 int err;
553
554 if (tty->ops->write == NULL)
555 return -EOPNOTSUPP;
556
557 /* OK. Find a free X.25 channel to use. */
558 sl = x25_asy_alloc();
559 if (sl == NULL)
560 return -ENFILE;
561
562 sl->tty = tty;
563 tty->disc_data = sl;
564 tty->receive_room = 65536;
565 tty_driver_flush_buffer(tty);
566 tty_ldisc_flush(tty);
567
568 /* Restore default settings */
569 sl->dev->type = ARPHRD_X25;
570
571 /* Perform the low-level X.25 async init */
572 err = x25_asy_open(sl->dev);
573 if (err) {
574 x25_asy_free(sl);
575 return err;
576 }
577 /* Done. We have linked the TTY line to a channel. */
578 return 0;
579 }
580
581
582 /*
583 * Close down an X.25 channel.
584 * This means flushing out any pending queues, and then restoring the
585 * TTY line discipline to what it was before it got hooked to X.25
586 * (which usually is TTY again).
587 */
x25_asy_close_tty(struct tty_struct * tty)588 static void x25_asy_close_tty(struct tty_struct *tty)
589 {
590 struct x25_asy *sl = tty->disc_data;
591 int err;
592
593 /* First make sure we're connected. */
594 if (!sl || sl->magic != X25_ASY_MAGIC)
595 return;
596
597 rtnl_lock();
598 if (sl->dev->flags & IFF_UP)
599 dev_close(sl->dev);
600 rtnl_unlock();
601
602 err = lapb_unregister(sl->dev);
603 if (err != LAPB_OK)
604 pr_err("x25_asy_close: lapb_unregister error: %d\n",
605 err);
606
607 tty->disc_data = NULL;
608 sl->tty = NULL;
609 x25_asy_free(sl);
610 }
611
612 /************************************************************************
613 * STANDARD X.25 ENCAPSULATION *
614 ************************************************************************/
615
x25_asy_esc(unsigned char * s,unsigned char * d,int len)616 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
617 {
618 unsigned char *ptr = d;
619 unsigned char c;
620
621 /*
622 * Send an initial END character to flush out any
623 * data that may have accumulated in the receiver
624 * due to line noise.
625 */
626
627 *ptr++ = X25_END; /* Send 10111110 bit seq */
628
629 /*
630 * For each byte in the packet, send the appropriate
631 * character sequence, according to the X.25 protocol.
632 */
633
634 while (len-- > 0) {
635 switch (c = *s++) {
636 case X25_END:
637 *ptr++ = X25_ESC;
638 *ptr++ = X25_ESCAPE(X25_END);
639 break;
640 case X25_ESC:
641 *ptr++ = X25_ESC;
642 *ptr++ = X25_ESCAPE(X25_ESC);
643 break;
644 default:
645 *ptr++ = c;
646 break;
647 }
648 }
649 *ptr++ = X25_END;
650 return ptr - d;
651 }
652
x25_asy_unesc(struct x25_asy * sl,unsigned char s)653 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
654 {
655
656 switch (s) {
657 case X25_END:
658 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
659 sl->rcount > 2)
660 x25_asy_bump(sl);
661 clear_bit(SLF_ESCAPE, &sl->flags);
662 sl->rcount = 0;
663 return;
664 case X25_ESC:
665 set_bit(SLF_ESCAPE, &sl->flags);
666 return;
667 case X25_ESCAPE(X25_ESC):
668 case X25_ESCAPE(X25_END):
669 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
670 s = X25_UNESCAPE(s);
671 break;
672 }
673 if (!test_bit(SLF_ERROR, &sl->flags)) {
674 if (sl->rcount < sl->buffsize) {
675 sl->rbuff[sl->rcount++] = s;
676 return;
677 }
678 sl->dev->stats.rx_over_errors++;
679 set_bit(SLF_ERROR, &sl->flags);
680 }
681 }
682
683
684 /* 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)685 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
686 unsigned int cmd, unsigned long arg)
687 {
688 struct x25_asy *sl = tty->disc_data;
689
690 /* First make sure we're connected. */
691 if (!sl || sl->magic != X25_ASY_MAGIC)
692 return -EINVAL;
693
694 switch (cmd) {
695 case SIOCGIFNAME:
696 if (copy_to_user((void __user *)arg, sl->dev->name,
697 strlen(sl->dev->name) + 1))
698 return -EFAULT;
699 return 0;
700 case SIOCSIFHWADDR:
701 return -EINVAL;
702 default:
703 return tty_mode_ioctl(tty, file, cmd, arg);
704 }
705 }
706
707 #ifdef CONFIG_COMPAT
x25_asy_compat_ioctl(struct tty_struct * tty,struct file * file,unsigned int cmd,unsigned long arg)708 static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
709 unsigned int cmd, unsigned long arg)
710 {
711 switch (cmd) {
712 case SIOCGIFNAME:
713 case SIOCSIFHWADDR:
714 return x25_asy_ioctl(tty, file, cmd,
715 (unsigned long)compat_ptr(arg));
716 }
717
718 return -ENOIOCTLCMD;
719 }
720 #endif
721
x25_asy_open_dev(struct net_device * dev)722 static int x25_asy_open_dev(struct net_device *dev)
723 {
724 struct x25_asy *sl = netdev_priv(dev);
725 if (sl->tty == NULL)
726 return -ENODEV;
727 return 0;
728 }
729
730 static const struct net_device_ops x25_asy_netdev_ops = {
731 .ndo_open = x25_asy_open_dev,
732 .ndo_stop = x25_asy_close,
733 .ndo_start_xmit = x25_asy_xmit,
734 .ndo_tx_timeout = x25_asy_timeout,
735 .ndo_change_mtu = x25_asy_change_mtu,
736 };
737
738 /* Initialise the X.25 driver. Called by the device init code */
x25_asy_setup(struct net_device * dev)739 static void x25_asy_setup(struct net_device *dev)
740 {
741 struct x25_asy *sl = netdev_priv(dev);
742
743 sl->magic = X25_ASY_MAGIC;
744 sl->dev = dev;
745 spin_lock_init(&sl->lock);
746 set_bit(SLF_INUSE, &sl->flags);
747
748 /*
749 * Finish setting up the DEVICE info.
750 */
751
752 dev->mtu = SL_MTU;
753 dev->min_mtu = 0;
754 dev->max_mtu = 65534;
755 dev->netdev_ops = &x25_asy_netdev_ops;
756 dev->watchdog_timeo = HZ*20;
757 dev->hard_header_len = 0;
758 dev->addr_len = 0;
759 dev->type = ARPHRD_X25;
760 dev->tx_queue_len = 10;
761
762 /* New-style flags. */
763 dev->flags = IFF_NOARP;
764 }
765
766 static struct tty_ldisc_ops x25_ldisc = {
767 .owner = THIS_MODULE,
768 .magic = TTY_LDISC_MAGIC,
769 .name = "X.25",
770 .open = x25_asy_open_tty,
771 .close = x25_asy_close_tty,
772 .ioctl = x25_asy_ioctl,
773 #ifdef CONFIG_COMPAT
774 .compat_ioctl = x25_asy_compat_ioctl,
775 #endif
776 .receive_buf = x25_asy_receive_buf,
777 .write_wakeup = x25_asy_write_wakeup,
778 };
779
init_x25_asy(void)780 static int __init init_x25_asy(void)
781 {
782 if (x25_asy_maxdev < 4)
783 x25_asy_maxdev = 4; /* Sanity */
784
785 pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n",
786 x25_asy_maxdev);
787
788 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
789 GFP_KERNEL);
790 if (!x25_asy_devs)
791 return -ENOMEM;
792
793 return tty_register_ldisc(N_X25, &x25_ldisc);
794 }
795
796
exit_x25_asy(void)797 static void __exit exit_x25_asy(void)
798 {
799 struct net_device *dev;
800 int i;
801
802 for (i = 0; i < x25_asy_maxdev; i++) {
803 dev = x25_asy_devs[i];
804 if (dev) {
805 struct x25_asy *sl = netdev_priv(dev);
806
807 spin_lock_bh(&sl->lock);
808 if (sl->tty)
809 tty_hangup(sl->tty);
810
811 spin_unlock_bh(&sl->lock);
812 /*
813 * VSV = if dev->start==0, then device
814 * unregistered while close proc.
815 */
816 unregister_netdev(dev);
817 free_netdev(dev);
818 }
819 }
820
821 kfree(x25_asy_devs);
822 tty_unregister_ldisc(N_X25);
823 }
824
825 module_init(init_x25_asy);
826 module_exit(exit_x25_asy);
827