lapb_iface.c revision 56d6c3d7a7963ee2a480232e5ef6a2f31635e80e 
1/*
2 *	LAPB release 002
3 *
4 *	This code REQUIRES 2.1.15 or higher/ NET3.038
5 *
6 *	This module:
7 *		This module is free software; you can redistribute it and/or
8 *		modify it under the terms of the GNU General Public License
9 *		as published by the Free Software Foundation; either version
10 *		2 of the License, or (at your option) any later version.
11 *
12 *	History
13 *	LAPB 001	Jonathan Naylor	Started Coding
14 *	LAPB 002	Jonathan Naylor	New timer architecture.
15 *	2000-10-29	Henner Eisen	lapb_data_indication() return status.
16 */
17
18#include <linux/module.h>
19#include <linux/errno.h>
20#include <linux/types.h>
21#include <linux/socket.h>
22#include <linux/in.h>
23#include <linux/kernel.h>
24#include <linux/jiffies.h>
25#include <linux/timer.h>
26#include <linux/string.h>
27#include <linux/sockios.h>
28#include <linux/net.h>
29#include <linux/inet.h>
30#include <linux/if_arp.h>
31#include <linux/skbuff.h>
32#include <net/sock.h>
33#include <asm/uaccess.h>
34#include <asm/system.h>
35#include <linux/fcntl.h>
36#include <linux/mm.h>
37#include <linux/interrupt.h>
38#include <linux/stat.h>
39#include <linux/init.h>
40#include <net/lapb.h>
41
42static struct list_head lapb_list = LIST_HEAD_INIT(lapb_list);
43static DEFINE_RWLOCK(lapb_list_lock);
44
45/*
46 *	Free an allocated lapb control block.
47 */
48static void lapb_free_cb(struct lapb_cb *lapb)
49{
50	kfree(lapb);
51}
52
53static __inline__ void lapb_hold(struct lapb_cb *lapb)
54{
55	atomic_inc(&lapb->refcnt);
56}
57
58static __inline__ void lapb_put(struct lapb_cb *lapb)
59{
60	if (atomic_dec_and_test(&lapb->refcnt))
61		lapb_free_cb(lapb);
62}
63
64/*
65 *	Socket removal during an interrupt is now safe.
66 */
67static void __lapb_remove_cb(struct lapb_cb *lapb)
68{
69	if (lapb->node.next) {
70		list_del(&lapb->node);
71		lapb_put(lapb);
72	}
73}
74
75/*
76 *	Add a socket to the bound sockets list.
77 */
78static void __lapb_insert_cb(struct lapb_cb *lapb)
79{
80	list_add(&lapb->node, &lapb_list);
81	lapb_hold(lapb);
82}
83
84static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
85{
86	struct list_head *entry;
87	struct lapb_cb *lapb, *use = NULL;
88
89	list_for_each(entry, &lapb_list) {
90		lapb = list_entry(entry, struct lapb_cb, node);
91		if (lapb->dev == dev) {
92			use = lapb;
93			break;
94		}
95	}
96
97	if (use)
98		lapb_hold(use);
99
100	return use;
101}
102
103static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
104{
105	struct lapb_cb *rc;
106
107	read_lock_bh(&lapb_list_lock);
108	rc = __lapb_devtostruct(dev);
109	read_unlock_bh(&lapb_list_lock);
110
111	return rc;
112}
113/*
114 *	Create an empty LAPB control block.
115 */
116static struct lapb_cb *lapb_create_cb(void)
117{
118	struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);
119
120
121	if (!lapb)
122		goto out;
123
124	skb_queue_head_init(&lapb->write_queue);
125	skb_queue_head_init(&lapb->ack_queue);
126
127	init_timer(&lapb->t1timer);
128	init_timer(&lapb->t2timer);
129
130	lapb->t1      = LAPB_DEFAULT_T1;
131	lapb->t2      = LAPB_DEFAULT_T2;
132	lapb->n2      = LAPB_DEFAULT_N2;
133	lapb->mode    = LAPB_DEFAULT_MODE;
134	lapb->window  = LAPB_DEFAULT_WINDOW;
135	lapb->state   = LAPB_STATE_0;
136	atomic_set(&lapb->refcnt, 1);
137out:
138	return lapb;
139}
140
141int lapb_register(struct net_device *dev, struct lapb_register_struct *callbacks)
142{
143	struct lapb_cb *lapb;
144	int rc = LAPB_BADTOKEN;
145
146	write_lock_bh(&lapb_list_lock);
147
148	lapb = __lapb_devtostruct(dev);
149	if (lapb) {
150		lapb_put(lapb);
151		goto out;
152	}
153
154	lapb = lapb_create_cb();
155	rc = LAPB_NOMEM;
156	if (!lapb)
157		goto out;
158
159	lapb->dev       = dev;
160	lapb->callbacks = *callbacks;
161
162	__lapb_insert_cb(lapb);
163
164	lapb_start_t1timer(lapb);
165
166	rc = LAPB_OK;
167out:
168	write_unlock_bh(&lapb_list_lock);
169	return rc;
170}
171
172int lapb_unregister(struct net_device *dev)
173{
174	struct lapb_cb *lapb;
175	int rc = LAPB_BADTOKEN;
176
177	write_lock_bh(&lapb_list_lock);
178	lapb = __lapb_devtostruct(dev);
179	if (!lapb)
180		goto out;
181
182	lapb_stop_t1timer(lapb);
183	lapb_stop_t2timer(lapb);
184
185	lapb_clear_queues(lapb);
186
187	__lapb_remove_cb(lapb);
188
189	lapb_put(lapb);
190	rc = LAPB_OK;
191out:
192	write_unlock_bh(&lapb_list_lock);
193	return rc;
194}
195
196int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
197{
198	int rc = LAPB_BADTOKEN;
199	struct lapb_cb *lapb = lapb_devtostruct(dev);
200
201	if (!lapb)
202		goto out;
203
204	parms->t1      = lapb->t1 / HZ;
205	parms->t2      = lapb->t2 / HZ;
206	parms->n2      = lapb->n2;
207	parms->n2count = lapb->n2count;
208	parms->state   = lapb->state;
209	parms->window  = lapb->window;
210	parms->mode    = lapb->mode;
211
212	if (!timer_pending(&lapb->t1timer))
213		parms->t1timer = 0;
214	else
215		parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
216
217	if (!timer_pending(&lapb->t2timer))
218		parms->t2timer = 0;
219	else
220		parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
221
222	lapb_put(lapb);
223	rc = LAPB_OK;
224out:
225	return rc;
226}
227
228int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
229{
230	int rc = LAPB_BADTOKEN;
231	struct lapb_cb *lapb = lapb_devtostruct(dev);
232
233	if (!lapb)
234		goto out;
235
236	rc = LAPB_INVALUE;
237	if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
238		goto out_put;
239
240	if (lapb->state == LAPB_STATE_0) {
241		if (parms->mode & LAPB_EXTENDED) {
242			if (parms->window < 1 || parms->window > 127)
243				goto out_put;
244		} else {
245			if (parms->window < 1 || parms->window > 7)
246				goto out_put;
247		}
248		lapb->mode    = parms->mode;
249		lapb->window  = parms->window;
250	}
251
252	lapb->t1    = parms->t1 * HZ;
253	lapb->t2    = parms->t2 * HZ;
254	lapb->n2    = parms->n2;
255
256	rc = LAPB_OK;
257out_put:
258	lapb_put(lapb);
259out:
260	return rc;
261}
262
263int lapb_connect_request(struct net_device *dev)
264{
265	struct lapb_cb *lapb = lapb_devtostruct(dev);
266	int rc = LAPB_BADTOKEN;
267
268	if (!lapb)
269		goto out;
270
271	rc = LAPB_OK;
272	if (lapb->state == LAPB_STATE_1)
273		goto out_put;
274
275	rc = LAPB_CONNECTED;
276	if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
277		goto out_put;
278
279	lapb_establish_data_link(lapb);
280
281#if LAPB_DEBUG > 0
282	printk(KERN_DEBUG "lapb: (%p) S0 -> S1\n", lapb->dev);
283#endif
284	lapb->state = LAPB_STATE_1;
285
286	rc = LAPB_OK;
287out_put:
288	lapb_put(lapb);
289out:
290	return rc;
291}
292
293int lapb_disconnect_request(struct net_device *dev)
294{
295	struct lapb_cb *lapb = lapb_devtostruct(dev);
296	int rc = LAPB_BADTOKEN;
297
298	if (!lapb)
299		goto out;
300
301	switch (lapb->state) {
302		case LAPB_STATE_0:
303			rc = LAPB_NOTCONNECTED;
304			goto out_put;
305
306		case LAPB_STATE_1:
307#if LAPB_DEBUG > 1
308			printk(KERN_DEBUG "lapb: (%p) S1 TX DISC(1)\n", lapb->dev);
309#endif
310#if LAPB_DEBUG > 0
311			printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n", lapb->dev);
312#endif
313			lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
314			lapb->state = LAPB_STATE_0;
315			lapb_start_t1timer(lapb);
316			rc = LAPB_NOTCONNECTED;
317			goto out_put;
318
319		case LAPB_STATE_2:
320			rc = LAPB_OK;
321			goto out_put;
322	}
323
324	lapb_clear_queues(lapb);
325	lapb->n2count = 0;
326	lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
327	lapb_start_t1timer(lapb);
328	lapb_stop_t2timer(lapb);
329	lapb->state = LAPB_STATE_2;
330
331#if LAPB_DEBUG > 1
332	printk(KERN_DEBUG "lapb: (%p) S3 DISC(1)\n", lapb->dev);
333#endif
334#if LAPB_DEBUG > 0
335	printk(KERN_DEBUG "lapb: (%p) S3 -> S2\n", lapb->dev);
336#endif
337
338	rc = LAPB_OK;
339out_put:
340	lapb_put(lapb);
341out:
342	return rc;
343}
344
345int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
346{
347	struct lapb_cb *lapb = lapb_devtostruct(dev);
348	int rc = LAPB_BADTOKEN;
349
350	if (!lapb)
351		goto out;
352
353	rc = LAPB_NOTCONNECTED;
354	if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
355		goto out_put;
356
357	skb_queue_tail(&lapb->write_queue, skb);
358	lapb_kick(lapb);
359	rc = LAPB_OK;
360out_put:
361	lapb_put(lapb);
362out:
363	return rc;
364}
365
366int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
367{
368	struct lapb_cb *lapb = lapb_devtostruct(dev);
369	int rc = LAPB_BADTOKEN;
370
371	if (lapb) {
372		lapb_data_input(lapb, skb);
373		lapb_put(lapb);
374		rc = LAPB_OK;
375	}
376
377	return rc;
378}
379
380void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
381{
382	if (lapb->callbacks.connect_confirmation)
383		lapb->callbacks.connect_confirmation(lapb->dev, reason);
384}
385
386void lapb_connect_indication(struct lapb_cb *lapb, int reason)
387{
388	if (lapb->callbacks.connect_indication)
389		lapb->callbacks.connect_indication(lapb->dev, reason);
390}
391
392void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
393{
394	if (lapb->callbacks.disconnect_confirmation)
395		lapb->callbacks.disconnect_confirmation(lapb->dev, reason);
396}
397
398void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
399{
400	if (lapb->callbacks.disconnect_indication)
401		lapb->callbacks.disconnect_indication(lapb->dev, reason);
402}
403
404int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
405{
406	if (lapb->callbacks.data_indication)
407		return lapb->callbacks.data_indication(lapb->dev, skb);
408
409	kfree_skb(skb);
410	return NET_RX_CN_HIGH; /* For now; must be != NET_RX_DROP */
411}
412
413int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
414{
415	int used = 0;
416
417	if (lapb->callbacks.data_transmit) {
418		lapb->callbacks.data_transmit(lapb->dev, skb);
419		used = 1;
420	}
421
422	return used;
423}
424
425EXPORT_SYMBOL(lapb_register);
426EXPORT_SYMBOL(lapb_unregister);
427EXPORT_SYMBOL(lapb_getparms);
428EXPORT_SYMBOL(lapb_setparms);
429EXPORT_SYMBOL(lapb_connect_request);
430EXPORT_SYMBOL(lapb_disconnect_request);
431EXPORT_SYMBOL(lapb_data_request);
432EXPORT_SYMBOL(lapb_data_received);
433
434static int __init lapb_init(void)
435{
436	return 0;
437}
438
439static void __exit lapb_exit(void)
440{
441	WARN_ON(!list_empty(&lapb_list));
442}
443
444MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
445MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
446MODULE_LICENSE("GPL");
447
448module_init(lapb_init);
449module_exit(lapb_exit);
450