aboutsummaryrefslogtreecommitdiff
path: root/net/lapb/lapb_iface.c
blob: d5d8d555c410dbe68b2b05a6a21284e1c2a44b1a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
/*
 *	LAPB release 002
 *
 *	This code REQUIRES 2.1.15 or higher/ NET3.038
 *
 *	This module:
 *		This module is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 *	History
 *	LAPB 001	Jonathan Naylor	Started Coding
 *	LAPB 002	Jonathan Naylor	New timer architecture.
 *	2000-10-29	Henner Eisen	lapb_data_indication() return status.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <net/lapb.h>

static LIST_HEAD(lapb_list);
static DEFINE_RWLOCK(lapb_list_lock);

/*
 *	Free an allocated lapb control block.
 */
static void lapb_free_cb(struct lapb_cb *lapb)
{
	kfree(lapb);
}

static __inline__ void lapb_hold(struct lapb_cb *lapb)
{
	atomic_inc(&lapb->refcnt);
}

static __inline__ void lapb_put(struct lapb_cb *lapb)
{
	if (atomic_dec_and_test(&lapb->refcnt))
		lapb_free_cb(lapb);
}

/*
 *	Socket removal during an interrupt is now safe.
 */
static void __lapb_remove_cb(struct lapb_cb *lapb)
{
	if (lapb->node.next) {
		list_del(&lapb->node);
		lapb_put(lapb);
	}
}

/*
 *	Add a socket to the bound sockets list.
 */
static void __lapb_insert_cb(struct lapb_cb *lapb)
{
	list_add(&lapb->node, &lapb_list);
	lapb_hold(lapb);
}

static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
{
	struct list_head *entry;
	struct lapb_cb *lapb, *use = NULL;

	list_for_each(entry, &lapb_list) {
		lapb = list_entry(entry, struct lapb_cb, node);
		if (lapb->dev == dev) {
			use = lapb;
			break;
		}
	}

	if (use)
		lapb_hold(use);

	return use;
}

static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
{
	struct lapb_cb *rc;

	read_lock_bh(&lapb_list_lock);
	rc = __lapb_devtostruct(dev);
	read_unlock_bh(&lapb_list_lock);

	return rc;
}
/*
 *	Create an empty LAPB control block.
 */
static struct lapb_cb *lapb_create_cb(void)
{
	struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);


	if (!lapb)
		goto out;

	skb_queue_head_init(&lapb->write_queue);
	skb_queue_head_init(&lapb->ack_queue);

	init_timer(&lapb->t1timer);
	init_timer(&lapb->t2timer);

	lapb->t1      = LAPB_DEFAULT_T1;
	lapb->t2      = LAPB_DEFAULT_T2;
	lapb->n2      = LAPB_DEFAULT_N2;
	lapb->mode    = LAPB_DEFAULT_MODE;
	lapb->window  = LAPB_DEFAULT_WINDOW;
	lapb->state   = LAPB_STATE_0;
	atomic_set(&lapb->refcnt, 1);
out:
	return lapb;
}

int lapb_register(struct net_device *dev, struct lapb_register_struct *callbacks)
{
	struct lapb_cb *lapb;
	int rc = LAPB_BADTOKEN;

	write_lock_bh(&lapb_list_lock);

	lapb = __lapb_devtostruct(dev);
	if (lapb) {
		lapb_put(lapb);
		goto out;
	}

	lapb = lapb_create_cb();
	rc = LAPB_NOMEM;
	if (!lapb)
		goto out;

	lapb->dev       = dev;
	lapb->callbacks = *callbacks;

	__lapb_insert_cb(lapb);

	lapb_start_t1timer(lapb);

	rc = LAPB_OK;
out:
	write_unlock_bh(&lapb_list_lock);
	return rc;
}

int lapb_unregister(struct net_device *dev)
{
	struct lapb_cb *lapb;
	int rc = LAPB_BADTOKEN;

	write_lock_bh(&lapb_list_lock);
	lapb = __lapb_devtostruct(dev);
	if (!lapb)
		goto out;

	lapb_stop_t1timer(lapb);
	lapb_stop_t2timer(lapb);

	lapb_clear_queues(lapb);

	__lapb_remove_cb(lapb);

	lapb_put(lapb);
	rc = LAPB_OK;
out:
	write_unlock_bh(&lapb_list_lock);
	return rc;
}

int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
{
	int rc = LAPB_BADTOKEN;
	struct lapb_cb *lapb = lapb_devtostruct(dev);

	if (!lapb)
		goto out;

	parms->t1      = lapb->t1 / HZ;
	parms->t2      = lapb->t2 / HZ;
	parms->n2      = lapb->n2;
	parms->n2count = lapb->n2count;
	parms->state   = lapb->state;
	parms->window  = lapb->window;
	parms->mode    = lapb->mode;

	if (!timer_pending(&lapb->t1timer))
		parms->t1timer = 0;
	else
		parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;

	if (!timer_pending(&lapb->t2timer))
		parms->t2timer = 0;
	else
		parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;

	lapb_put(lapb);
	rc = LAPB_OK;
out:
	return rc;
}

int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
{
	int rc = LAPB_BADTOKEN;
	struct lapb_cb *lapb = lapb_devtostruct(dev);

	if (!lapb)
		goto out;

	rc = LAPB_INVALUE;
	if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
		goto out_put;

	if (lapb->state == LAPB_STATE_0) {
		if (parms->mode & LAPB_EXTENDED) {
			if (parms->window < 1 || parms->window > 127)
				goto out_put;
		} else {
			if (parms->window < 1 || parms->window > 7)
				goto out_put;
		}
		lapb->mode    = parms->mode;
		lapb->window  = parms->window;
	}

	lapb->t1    = parms->t1 * HZ;
	lapb->t2    = parms->t2 * HZ;
	lapb->n2    = parms->n2;

	rc = LAPB_OK;
out_put:
	lapb_put(lapb);
out:
	return rc;
}

int lapb_connect_request(struct net_device *dev)
{
	struct lapb_cb *lapb = lapb_devtostruct(dev);
	int rc = LAPB_BADTOKEN;

	if (!lapb)
		goto out;

	rc = LAPB_OK;
	if (lapb->state == LAPB_STATE_1)
		goto out_put;

	rc = LAPB_CONNECTED;
	if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
		goto out_put;

	lapb_establish_data_link(lapb);

#if LAPB_DEBUG > 0
	printk(KERN_DEBUG "lapb: (%p) S0 -> S1\n", lapb->dev);
#endif
	lapb->state = LAPB_STATE_1;

	rc = LAPB_OK;
out_put:
	lapb_put(lapb);
out:
	return rc;
}

int lapb_disconnect_request(struct net_device *dev)
{
	struct lapb_cb *lapb = lapb_devtostruct(dev);
	int rc = LAPB_BADTOKEN;

	if (!lapb)
		goto out;

	switch (lapb->state) {
		case LAPB_STATE_0:
			rc = LAPB_NOTCONNECTED;
			goto out_put;

		case LAPB_STATE_1:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S1 TX DISC(1)\n", lapb->dev);
#endif
#if LAPB_DEBUG > 0
			printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n", lapb->dev);
#endif
			lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
			lapb->state = LAPB_STATE_0;
			lapb_start_t1timer(lapb);
			rc = LAPB_NOTCONNECTED;
			goto out_put;

		case LAPB_STATE_2:
			rc = LAPB_OK;
			goto out_put;
	}

	lapb_clear_queues(lapb);
	lapb->n2count = 0;
	lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
	lapb_start_t1timer(lapb);
	lapb_stop_t2timer(lapb);
	lapb->state = LAPB_STATE_2;

#if LAPB_DEBUG > 1
	printk(KERN_DEBUG "lapb: (%p) S3 DISC(1)\n", lapb->dev);
#endif
#if LAPB_DEBUG > 0
	printk(KERN_DEBUG "lapb: (%p) S3 -> S2\n", lapb->dev);
#endif

	rc = LAPB_OK;
out_put:
	lapb_put(lapb);
out:
	return rc;
}

int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
{
	struct lapb_cb *lapb = lapb_devtostruct(dev);
	int rc = LAPB_BADTOKEN;

	if (!lapb)
		goto out;

	rc = LAPB_NOTCONNECTED;
	if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
		goto out_put;

	skb_queue_tail(&lapb->write_queue, skb);
	lapb_kick(lapb);
	rc = LAPB_OK;
out_put:
	lapb_put(lapb);
out:
	return rc;
}

int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
{
	struct lapb_cb *lapb = lapb_devtostruct(dev);
	int rc = LAPB_BADTOKEN;

	if (lapb) {
		lapb_data_input(lapb, skb);
		lapb_put(lapb);
		rc = LAPB_OK;
	}

	return rc;
}

void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
{
	if (lapb->callbacks.connect_confirmation)
		lapb->callbacks.connect_confirmation(lapb->dev, reason);
}

void lapb_connect_indication(struct lapb_cb *lapb, int reason)
{
	if (lapb->callbacks.connect_indication)
		lapb->callbacks.connect_indication(lapb->dev, reason);
}

void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
{
	if (lapb->callbacks.disconnect_confirmation)
		lapb->callbacks.disconnect_confirmation(lapb->dev, reason);
}

void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
{
	if (lapb->callbacks.disconnect_indication)
		lapb->callbacks.disconnect_indication(lapb->dev, reason);
}

int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
{
	if (lapb->callbacks.data_indication)
		return lapb->callbacks.data_indication(lapb->dev, skb);

	kfree_skb(skb);
	return NET_RX_SUCCESS; /* For now; must be != NET_RX_DROP */
}

int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
{
	int used = 0;

	if (lapb->callbacks.data_transmit) {
		lapb->callbacks.data_transmit(lapb->dev, skb);
		used = 1;
	}

	return used;
}

EXPORT_SYMBOL(lapb_register);
EXPORT_SYMBOL(lapb_unregister);
EXPORT_SYMBOL(lapb_getparms);
EXPORT_SYMBOL(lapb_setparms);
EXPORT_SYMBOL(lapb_connect_request);
EXPORT_SYMBOL(lapb_disconnect_request);
EXPORT_SYMBOL(lapb_data_request);
EXPORT_SYMBOL(lapb_data_received);

static int __init lapb_init(void)
{
	return 0;
}

static void __exit lapb_exit(void)
{
	WARN_ON(!list_empty(&lapb_list));
}

MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
MODULE_LICENSE("GPL");

module_init(lapb_init);
module_exit(lapb_exit);