blob: 472bd0e6dd9d48a5a22db8ce9efc87968f506fb1 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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#include <linux/module.h>
18
19#include <asm/system.h>
Alan Coxf34d7a52008-04-30 00:54:13 -070020#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/bitops.h>
22#include <linux/string.h>
23#include <linux/mm.h>
24#include <linux/interrupt.h>
25#include <linux/in.h>
26#include <linux/tty.h>
27#include <linux/errno.h>
28#include <linux/netdevice.h>
29#include <linux/etherdevice.h>
30#include <linux/skbuff.h>
31#include <linux/if_arp.h>
32#include <linux/x25.h>
33#include <linux/lapb.h>
34#include <linux/init.h>
Ben Hutchings3e3cda92008-05-06 19:41:48 +010035#include <linux/rtnetlink.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include "x25_asy.h"
37
38#include <net/x25device.h>
39
40static struct net_device **x25_asy_devs;
41static int x25_asy_maxdev = SL_NRUNIT;
42
43module_param(x25_asy_maxdev, int, 0);
44MODULE_LICENSE("GPL");
45
46static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
47static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
48static void x25_asy_setup(struct net_device *dev);
49
50/* Find a free X.25 channel, and link in this `tty' line. */
51static struct x25_asy *x25_asy_alloc(void)
52{
53 struct net_device *dev = NULL;
54 struct x25_asy *sl;
55 int i;
56
57 if (x25_asy_devs == NULL)
58 return NULL; /* Master array missing ! */
59
60 for (i = 0; i < x25_asy_maxdev; i++) {
61 dev = x25_asy_devs[i];
62
63 /* Not allocated ? */
64 if (dev == NULL)
65 break;
66
Wang Chen8f15ea42008-11-12 23:38:36 -080067 sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 /* Not in use ? */
69 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
70 return sl;
71 }
72
73
74 /* Sorry, too many, all slots in use */
75 if (i >= x25_asy_maxdev)
76 return NULL;
77
78 /* If no channels are available, allocate one */
79 if (!dev) {
80 char name[IFNAMSIZ];
81 sprintf(name, "x25asy%d", i);
82
83 dev = alloc_netdev(sizeof(struct x25_asy),
84 name, x25_asy_setup);
85 if (!dev)
86 return NULL;
87
88 /* Initialize channel control data */
Wang Chen8f15ea42008-11-12 23:38:36 -080089 sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 dev->base_addr = i;
91
92 /* register device so that it can be ifconfig'ed */
93 if (register_netdev(dev) == 0) {
94 /* (Re-)Set the INUSE bit. Very Important! */
95 set_bit(SLF_INUSE, &sl->flags);
96 x25_asy_devs[i] = dev;
97 return sl;
98 } else {
Alan Coxf34d7a52008-04-30 00:54:13 -070099 printk(KERN_WARNING "x25_asy_alloc() - register_netdev() failure.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 free_netdev(dev);
101 }
102 }
103 return NULL;
104}
105
106
107/* Free an X.25 channel. */
108static void x25_asy_free(struct x25_asy *sl)
109{
110 /* Free all X.25 frame buffers. */
Jesper Juhl6a5d3622005-05-03 14:33:27 -0700111 kfree(sl->rbuff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 sl->rbuff = NULL;
Jesper Juhl6a5d3622005-05-03 14:33:27 -0700113 kfree(sl->xbuff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 sl->xbuff = NULL;
115
Alan Coxf34d7a52008-04-30 00:54:13 -0700116 if (!test_and_clear_bit(SLF_INUSE, &sl->flags))
117 printk(KERN_ERR "%s: x25_asy_free for already free unit.\n",
118 sl->dev->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119}
120
121static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
122{
Wang Chen8f15ea42008-11-12 23:38:36 -0800123 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 unsigned char *xbuff, *rbuff;
Alan Coxf34d7a52008-04-30 00:54:13 -0700125 int len = 2 * newmtu;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
Robert P. J. Day5cbded52006-12-13 00:35:56 -0800127 xbuff = kmalloc(len + 4, GFP_ATOMIC);
128 rbuff = kmalloc(len + 4, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
Alan Coxf34d7a52008-04-30 00:54:13 -0700130 if (xbuff == NULL || rbuff == NULL) {
131 printk(KERN_WARNING "%s: unable to grow X.25 buffers, MTU change cancelled.\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 dev->name);
Jesper Juhl6a5d3622005-05-03 14:33:27 -0700133 kfree(xbuff);
134 kfree(rbuff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 return -ENOMEM;
136 }
137
138 spin_lock_bh(&sl->lock);
139 xbuff = xchg(&sl->xbuff, xbuff);
140 if (sl->xleft) {
141 if (sl->xleft <= len) {
142 memcpy(sl->xbuff, sl->xhead, sl->xleft);
143 } else {
144 sl->xleft = 0;
145 sl->stats.tx_dropped++;
146 }
147 }
148 sl->xhead = sl->xbuff;
149
150 rbuff = xchg(&sl->rbuff, rbuff);
151 if (sl->rcount) {
152 if (sl->rcount <= len) {
153 memcpy(sl->rbuff, rbuff, sl->rcount);
154 } else {
155 sl->rcount = 0;
156 sl->stats.rx_over_errors++;
157 set_bit(SLF_ERROR, &sl->flags);
158 }
159 }
160
161 dev->mtu = newmtu;
162 sl->buffsize = len;
163
164 spin_unlock_bh(&sl->lock);
165
Jesper Juhl6a5d3622005-05-03 14:33:27 -0700166 kfree(xbuff);
167 kfree(rbuff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 return 0;
169}
170
171
172/* Set the "sending" flag. This must be atomic, hence the ASM. */
173
174static inline void x25_asy_lock(struct x25_asy *sl)
175{
176 netif_stop_queue(sl->dev);
177}
178
179
180/* Clear the "sending" flag. This must be atomic, hence the ASM. */
181
182static inline void x25_asy_unlock(struct x25_asy *sl)
183{
184 netif_wake_queue(sl->dev);
185}
186
187/* Send one completely decapsulated IP datagram to the IP layer. */
188
189static void x25_asy_bump(struct x25_asy *sl)
190{
191 struct sk_buff *skb;
192 int count;
193 int err;
194
195 count = sl->rcount;
Alan Coxf34d7a52008-04-30 00:54:13 -0700196 sl->stats.rx_bytes += count;
197
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 skb = dev_alloc_skb(count+1);
Alan Coxf34d7a52008-04-30 00:54:13 -0700199 if (skb == NULL) {
200 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n",
201 sl->dev->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 sl->stats.rx_dropped++;
203 return;
204 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700205 skb_push(skb, 1); /* LAPB internal control */
206 memcpy(skb_put(skb, count), sl->rbuff, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 skb->protocol = x25_type_trans(skb, sl->dev);
Alan Coxf34d7a52008-04-30 00:54:13 -0700208 err = lapb_data_received(skb->dev, skb);
209 if (err != LAPB_OK) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 kfree_skb(skb);
Alan Coxf34d7a52008-04-30 00:54:13 -0700211 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
212 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 netif_rx(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 sl->stats.rx_packets++;
215 }
216}
217
218/* Encapsulate one IP datagram and stuff into a TTY queue. */
219static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
220{
221 unsigned char *p;
222 int actual, count, mtu = sl->dev->mtu;
223
Alan Coxf34d7a52008-04-30 00:54:13 -0700224 if (len > mtu) {
225 /* Sigh, shouldn't occur BUT ... */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 len = mtu;
Alan Coxf34d7a52008-04-30 00:54:13 -0700227 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
228 sl->dev->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 sl->stats.tx_dropped++;
230 x25_asy_unlock(sl);
231 return;
232 }
233
234 p = icp;
235 count = x25_asy_esc(p, (unsigned char *) sl->xbuff, len);
236
237 /* Order of next two lines is *very* important.
238 * When we are sending a little amount of data,
239 * the transfer may be completed inside driver.write()
240 * routine, because it's running with interrupts enabled.
241 * In this case we *never* got WRITE_WAKEUP event,
242 * if we did not request it before write operation.
243 * 14 Oct 1994 Dmitry Gorodchanin.
244 */
Alan Cox8a1ec212008-12-05 22:31:52 -0800245 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
Alan Coxf34d7a52008-04-30 00:54:13 -0700246 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 sl->xleft = count - actual;
248 sl->xhead = sl->xbuff + actual;
249 /* VSV */
250 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
251}
252
253/*
254 * Called by the driver when there's room for more data. If we have
255 * more packets to send, we send them here.
256 */
257static void x25_asy_write_wakeup(struct tty_struct *tty)
258{
259 int actual;
Alan Coxd2b88812008-12-05 22:32:22 -0800260 struct x25_asy *sl = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
262 /* First make sure we're connected. */
263 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
264 return;
265
Alan Coxf34d7a52008-04-30 00:54:13 -0700266 if (sl->xleft <= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 /* Now serial buffer is almost free & we can start
268 * transmission of another packet */
269 sl->stats.tx_packets++;
Alan Cox8a1ec212008-12-05 22:31:52 -0800270 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 x25_asy_unlock(sl);
272 return;
273 }
274
Alan Coxf34d7a52008-04-30 00:54:13 -0700275 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 sl->xleft -= actual;
277 sl->xhead += actual;
278}
279
280static void x25_asy_timeout(struct net_device *dev)
281{
Wang Chen8f15ea42008-11-12 23:38:36 -0800282 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
284 spin_lock(&sl->lock);
285 if (netif_queue_stopped(dev)) {
286 /* May be we must check transmitter timeout here ?
287 * 14 Oct 1994 Dmitry Gorodchanin.
288 */
289 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
Alan Coxf34d7a52008-04-30 00:54:13 -0700290 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 "bad line quality" : "driver error");
292 sl->xleft = 0;
Alan Cox8a1ec212008-12-05 22:31:52 -0800293 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 x25_asy_unlock(sl);
295 }
296 spin_unlock(&sl->lock);
297}
298
299/* Encapsulate an IP datagram and kick it into a TTY queue. */
300
301static int x25_asy_xmit(struct sk_buff *skb, struct net_device *dev)
302{
Wang Chen8f15ea42008-11-12 23:38:36 -0800303 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 int err;
305
306 if (!netif_running(sl->dev)) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700307 printk(KERN_ERR "%s: xmit call when iface is down\n",
308 dev->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 kfree_skb(skb);
310 return 0;
311 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700312
313 switch (skb->data[0]) {
314 case 0x00:
315 break;
316 case 0x01: /* Connection request .. do nothing */
317 err = lapb_connect_request(dev);
318 if (err != LAPB_OK)
319 printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
320 kfree_skb(skb);
321 return 0;
322 case 0x02: /* Disconnect request .. do nothing - hang up ?? */
323 err = lapb_disconnect_request(dev);
324 if (err != LAPB_OK)
325 printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
326 default:
327 kfree_skb(skb);
328 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700330 skb_pull(skb, 1); /* Remove control byte */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 /*
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 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700341
342 err = lapb_data_request(dev, skb);
343 if (err != LAPB_OK) {
344 printk(KERN_ERR "x25_asy: lapb_data_request error - %d\n", err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 kfree_skb(skb);
346 return 0;
347 }
348 return 0;
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 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700360
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
362{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 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 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700371
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
373{
Wang Chen8f15ea42008-11-12 23:38:36 -0800374 struct x25_asy *sl = netdev_priv(dev);
Alan Coxf34d7a52008-04-30 00:54:13 -0700375
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 spin_lock(&sl->lock);
Alan Coxf34d7a52008-04-30 00:54:13 -0700377 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 spin_unlock(&sl->lock);
379 printk(KERN_ERR "x25_asy: tbusy drop\n");
380 kfree_skb(skb);
381 return;
382 }
383 /* We were not busy, so we are now... :-) */
Alan Coxf34d7a52008-04-30 00:54:13 -0700384 if (skb != NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 x25_asy_lock(sl);
Alan Coxf34d7a52008-04-30 00:54:13 -0700386 sl->stats.tx_bytes += skb->len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 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 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700396
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397static void x25_asy_connected(struct net_device *dev, int reason)
398{
Wang Chen8f15ea42008-11-12 23:38:36 -0800399 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 struct sk_buff *skb;
401 unsigned char *ptr;
402
Alan Coxf34d7a52008-04-30 00:54:13 -0700403 skb = dev_alloc_skb(1);
404 if (skb == NULL) {
405 printk(KERN_ERR "x25_asy: out of memory\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 return;
407 }
408
409 ptr = skb_put(skb, 1);
410 *ptr = 0x01;
411
412 skb->protocol = x25_type_trans(skb, sl->dev);
413 netif_rx(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414}
415
416static void x25_asy_disconnected(struct net_device *dev, int reason)
417{
Wang Chen8f15ea42008-11-12 23:38:36 -0800418 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 struct sk_buff *skb;
420 unsigned char *ptr;
421
Alan Coxf34d7a52008-04-30 00:54:13 -0700422 skb = dev_alloc_skb(1);
423 if (skb == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 printk(KERN_ERR "x25_asy: out of memory\n");
425 return;
426 }
427
428 ptr = skb_put(skb, 1);
429 *ptr = 0x02;
430
431 skb->protocol = x25_type_trans(skb, sl->dev);
432 netif_rx(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433}
434
435static 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
446/* Open the low-level part of the X.25 channel. Easy! */
447static int x25_asy_open(struct net_device *dev)
448{
Wang Chen8f15ea42008-11-12 23:38:36 -0800449 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 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
Robert P. J. Day5cbded52006-12-13 00:35:56 -0800465 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
Alan Coxf34d7a52008-04-30 00:54:13 -0700466 if (sl->rbuff == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 goto norbuff;
Robert P. J. Day5cbded52006-12-13 00:35:56 -0800468 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
Alan Coxf34d7a52008-04-30 00:54:13 -0700469 if (sl->xbuff == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 goto noxbuff;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471
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);
Alan Coxf34d7a52008-04-30 00:54:13 -0700478
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 /*
480 * Now attach LAPB
481 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700482 err = lapb_register(dev, &x25_asy_callbacks);
483 if (err == LAPB_OK)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 return 0;
485
486 /* Cleanup */
487 kfree(sl->xbuff);
488noxbuff:
489 kfree(sl->rbuff);
490norbuff:
491 return -ENOMEM;
492}
493
494
495/* Close the low-level part of the X.25 channel. Easy! */
496static int x25_asy_close(struct net_device *dev)
497{
Wang Chen8f15ea42008-11-12 23:38:36 -0800498 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 int err;
500
501 spin_lock(&sl->lock);
Alan Coxf34d7a52008-04-30 00:54:13 -0700502 if (sl->tty)
Alan Cox8a1ec212008-12-05 22:31:52 -0800503 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
505 netif_stop_queue(dev);
506 sl->rcount = 0;
507 sl->xleft = 0;
Alan Coxf34d7a52008-04-30 00:54:13 -0700508 err = lapb_unregister(dev);
509 if (err != LAPB_OK)
510 printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",
511 err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 spin_unlock(&sl->lock);
513 return 0;
514}
515
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516/*
517 * Handle the 'receiver data ready' interrupt.
518 * This function is called by the 'tty_io' module in the kernel when
519 * a block of X.25 data has been received, which can now be decapsulated
520 * and sent on to some IP layer for further processing.
521 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700522
523static void x25_asy_receive_buf(struct tty_struct *tty,
524 const unsigned char *cp, char *fp, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525{
Alan Coxd2b88812008-12-05 22:32:22 -0800526 struct x25_asy *sl = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
528 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
529 return;
530
531
532 /* Read the characters out of the buffer */
533 while (count--) {
534 if (fp && *fp++) {
Alan Coxf34d7a52008-04-30 00:54:13 -0700535 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 sl->stats.rx_errors++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 cp++;
538 continue;
539 }
540 x25_asy_unesc(sl, *cp++);
541 }
542}
543
544/*
545 * Open the high-level part of the X.25 channel.
546 * This function is called by the TTY module when the
547 * X.25 line discipline is called for. Because we are
548 * sure the tty line exists, we only have to link it to
549 * a free X.25 channel...
550 */
551
552static int x25_asy_open_tty(struct tty_struct *tty)
553{
Alan Coxd2b88812008-12-05 22:32:22 -0800554 struct x25_asy *sl = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 int err;
556
Alan Coxf34d7a52008-04-30 00:54:13 -0700557 if (tty->ops->write == NULL)
558 return -EOPNOTSUPP;
559
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 /* First make sure we're not already connected. */
Alan Coxf34d7a52008-04-30 00:54:13 -0700561 if (sl && sl->magic == X25_ASY_MAGIC)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 return -EEXIST;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563
564 /* OK. Find a free X.25 channel to use. */
Alan Coxf34d7a52008-04-30 00:54:13 -0700565 sl = x25_asy_alloc();
566 if (sl == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 return -ENFILE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568
569 sl->tty = tty;
570 tty->disc_data = sl;
Alan Cox33f0f882006-01-09 20:54:13 -0800571 tty->receive_room = 65536;
Alan Coxf34d7a52008-04-30 00:54:13 -0700572 tty_driver_flush_buffer(tty);
Alan Cox11b0cc32008-02-08 15:00:48 -0800573 tty_ldisc_flush(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
575 /* Restore default settings */
576 sl->dev->type = ARPHRD_X25;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577
Alan Coxf34d7a52008-04-30 00:54:13 -0700578 /* Perform the low-level X.25 async init */
579 err = x25_asy_open(sl->dev);
580 if (err)
581 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 /* Done. We have linked the TTY line to a channel. */
583 return sl->dev->base_addr;
584}
585
586
587/*
588 * Close down an X.25 channel.
589 * This means flushing out any pending queues, and then restoring the
590 * TTY line discipline to what it was before it got hooked to X.25
591 * (which usually is TTY again).
592 */
593static void x25_asy_close_tty(struct tty_struct *tty)
594{
Alan Coxd2b88812008-12-05 22:32:22 -0800595 struct x25_asy *sl = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596
597 /* First make sure we're connected. */
598 if (!sl || sl->magic != X25_ASY_MAGIC)
599 return;
600
Ben Hutchings3e3cda92008-05-06 19:41:48 +0100601 rtnl_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 if (sl->dev->flags & IFF_UP)
Alan Coxf34d7a52008-04-30 00:54:13 -0700603 dev_close(sl->dev);
Ben Hutchings3e3cda92008-05-06 19:41:48 +0100604 rtnl_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605
606 tty->disc_data = NULL;
607 sl->tty = NULL;
608 x25_asy_free(sl);
609}
610
611
612static struct net_device_stats *x25_asy_get_stats(struct net_device *dev)
613{
Wang Chen8f15ea42008-11-12 23:38:36 -0800614 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 return &sl->stats;
616}
617
618
619 /************************************************************************
620 * STANDARD X.25 ENCAPSULATION *
621 ************************************************************************/
622
623int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
624{
625 unsigned char *ptr = d;
626 unsigned char c;
627
628 /*
629 * Send an initial END character to flush out any
630 * data that may have accumulated in the receiver
631 * due to line noise.
632 */
633
634 *ptr++ = X25_END; /* Send 10111110 bit seq */
635
636 /*
637 * For each byte in the packet, send the appropriate
638 * character sequence, according to the X.25 protocol.
639 */
640
Alan Coxf34d7a52008-04-30 00:54:13 -0700641 while (len-- > 0) {
642 switch (c = *s++) {
643 case X25_END:
644 *ptr++ = X25_ESC;
645 *ptr++ = X25_ESCAPE(X25_END);
646 break;
647 case X25_ESC:
648 *ptr++ = X25_ESC;
649 *ptr++ = X25_ESCAPE(X25_ESC);
650 break;
651 default:
652 *ptr++ = c;
653 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 }
655 }
656 *ptr++ = X25_END;
657 return (ptr - d);
658}
659
660static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
661{
662
Alan Coxf34d7a52008-04-30 00:54:13 -0700663 switch (s) {
664 case X25_END:
665 if (!test_and_clear_bit(SLF_ERROR, &sl->flags)
666 && sl->rcount > 2)
667 x25_asy_bump(sl);
668 clear_bit(SLF_ESCAPE, &sl->flags);
669 sl->rcount = 0;
670 return;
671 case X25_ESC:
672 set_bit(SLF_ESCAPE, &sl->flags);
673 return;
674 case X25_ESCAPE(X25_ESC):
675 case X25_ESCAPE(X25_END):
676 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
677 s = X25_UNESCAPE(s);
678 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 }
Alan Coxf34d7a52008-04-30 00:54:13 -0700680 if (!test_bit(SLF_ERROR, &sl->flags)) {
681 if (sl->rcount < sl->buffsize) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682 sl->rbuff[sl->rcount++] = s;
683 return;
684 }
685 sl->stats.rx_over_errors++;
686 set_bit(SLF_ERROR, &sl->flags);
687 }
688}
689
690
691/* Perform I/O control on an active X.25 channel. */
692static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
693 unsigned int cmd, unsigned long arg)
694{
Alan Coxd2b88812008-12-05 22:32:22 -0800695 struct x25_asy *sl = tty->disc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696
697 /* First make sure we're connected. */
698 if (!sl || sl->magic != X25_ASY_MAGIC)
699 return -EINVAL;
700
Alan Coxf34d7a52008-04-30 00:54:13 -0700701 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 case SIOCGIFNAME:
703 if (copy_to_user((void __user *)arg, sl->dev->name,
704 strlen(sl->dev->name) + 1))
705 return -EFAULT;
706 return 0;
707 case SIOCSIFHWADDR:
708 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 default:
Alan Coxd0127532007-11-07 01:27:34 -0800710 return tty_mode_ioctl(tty, file, cmd, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 }
712}
713
714static int x25_asy_open_dev(struct net_device *dev)
715{
Wang Chen8f15ea42008-11-12 23:38:36 -0800716 struct x25_asy *sl = netdev_priv(dev);
Alan Coxf34d7a52008-04-30 00:54:13 -0700717 if (sl->tty == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 return -ENODEV;
719 return 0;
720}
721
722/* Initialise the X.25 driver. Called by the device init code */
723static void x25_asy_setup(struct net_device *dev)
724{
Wang Chen8f15ea42008-11-12 23:38:36 -0800725 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726
727 sl->magic = X25_ASY_MAGIC;
728 sl->dev = dev;
729 spin_lock_init(&sl->lock);
730 set_bit(SLF_INUSE, &sl->flags);
731
732 /*
Alan Coxf34d7a52008-04-30 00:54:13 -0700733 * Finish setting up the DEVICE info.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 */
Alan Coxf34d7a52008-04-30 00:54:13 -0700735
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 dev->mtu = SL_MTU;
737 dev->hard_start_xmit = x25_asy_xmit;
738 dev->tx_timeout = x25_asy_timeout;
739 dev->watchdog_timeo = HZ*20;
740 dev->open = x25_asy_open_dev;
741 dev->stop = x25_asy_close;
742 dev->get_stats = x25_asy_get_stats;
743 dev->change_mtu = x25_asy_change_mtu;
744 dev->hard_header_len = 0;
745 dev->addr_len = 0;
746 dev->type = ARPHRD_X25;
747 dev->tx_queue_len = 10;
748
749 /* New-style flags. */
750 dev->flags = IFF_NOARP;
751}
752
Alan Coxa352def2008-07-16 21:53:12 +0100753static struct tty_ldisc_ops x25_ldisc = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 .owner = THIS_MODULE,
755 .magic = TTY_LDISC_MAGIC,
756 .name = "X.25",
757 .open = x25_asy_open_tty,
758 .close = x25_asy_close_tty,
759 .ioctl = x25_asy_ioctl,
760 .receive_buf = x25_asy_receive_buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 .write_wakeup = x25_asy_write_wakeup,
762};
763
764static int __init init_x25_asy(void)
765{
766 if (x25_asy_maxdev < 4)
767 x25_asy_maxdev = 4; /* Sanity */
768
769 printk(KERN_INFO "X.25 async: version 0.00 ALPHA "
Alan Coxf34d7a52008-04-30 00:54:13 -0700770 "(dynamic channels, max=%d).\n", x25_asy_maxdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771
Alan Coxf34d7a52008-04-30 00:54:13 -0700772 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
773 GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 if (!x25_asy_devs) {
775 printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] "
776 "array! Uaargh! (-> No X.25 available)\n");
777 return -ENOMEM;
778 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779
780 return tty_register_ldisc(N_X25, &x25_ldisc);
781}
782
783
784static void __exit exit_x25_asy(void)
785{
786 struct net_device *dev;
787 int i;
788
789 for (i = 0; i < x25_asy_maxdev; i++) {
790 dev = x25_asy_devs[i];
791 if (dev) {
Wang Chen8f15ea42008-11-12 23:38:36 -0800792 struct x25_asy *sl = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793
794 spin_lock_bh(&sl->lock);
Alan Coxf34d7a52008-04-30 00:54:13 -0700795 if (sl->tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 tty_hangup(sl->tty);
797
798 spin_unlock_bh(&sl->lock);
799 /*
800 * VSV = if dev->start==0, then device
801 * unregistered while close proc.
802 */
803 unregister_netdev(dev);
804 free_netdev(dev);
805 }
806 }
807
808 kfree(x25_asy_devs);
Alexey Dobriyan64ccd712005-06-23 00:10:33 -0700809 tty_unregister_ldisc(N_X25);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810}
811
812module_init(init_x25_asy);
813module_exit(exit_x25_asy);