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 <linux/slab.h>
33#include <net/sock.h>
34#include <asm/uaccess.h>
35#include <asm/system.h>
36#include <linux/fcntl.h>
37#include <linux/mm.h>
38#include <linux/interrupt.h>
39#include <linux/stat.h>
40#include <linux/init.h>
41#include <net/lapb.h>
42
43static LIST_HEAD(lapb_list);
44static DEFINE_RWLOCK(lapb_list_lock);
45
46/*
47 *	Free an allocated lapb control block.
48 */
49static void lapb_free_cb(struct lapb_cb *lapb)
50{
51	kfree(lapb);
52}
53
54static __inline__ void lapb_hold(struct lapb_cb *lapb)
55{
56	atomic_inc(&lapb->refcnt);
57}
58
59static __inline__ void lapb_put(struct lapb_cb *lapb)
60{
61	if (atomic_dec_and_test(&lapb->refcnt))
62		lapb_free_cb(lapb);
63}
64
65/*
66 *	Socket removal during an interrupt is now safe.
67 */
68static void __lapb_remove_cb(struct lapb_cb *lapb)
69{
70	if (lapb->node.next) {
71		list_del(&lapb->node);
72		lapb_put(lapb);
73	}
74}
75
76/*
77 *	Add a socket to the bound sockets list.
78 */
79static void __lapb_insert_cb(struct lapb_cb *lapb)
80{
81	list_add(&lapb->node, &lapb_list);
82	lapb_hold(lapb);
83}
84
85static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
86{
87	struct list_head *entry;
88	struct lapb_cb *lapb, *use = NULL;
89
90	list_for_each(entry, &lapb_list) {
91		lapb = list_entry(entry, struct lapb_cb, node);
92		if (lapb->dev == dev) {
93			use = lapb;
94			break;
95		}
96	}
97
98	if (use)
99		lapb_hold(use);
100
101	return use;
102}
103
104static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
105{
106	struct lapb_cb *rc;
107
108	read_lock_bh(&lapb_list_lock);
109	rc = __lapb_devtostruct(dev);
110	read_unlock_bh(&lapb_list_lock);
111
112	return rc;
113}
114/*
115 *	Create an empty LAPB control block.
116 */
117static struct lapb_cb *lapb_create_cb(void)
118{
119	struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);
120
121
122	if (!lapb)
123		goto out;
124
125	skb_queue_head_init(&lapb->write_queue);
126	skb_queue_head_init(&lapb->ack_queue);
127
128	init_timer(&lapb->t1timer);
129	init_timer(&lapb->t2timer);
130
131	lapb->t1      = LAPB_DEFAULT_T1;
132	lapb->t2      = LAPB_DEFAULT_T2;
133	lapb->n2      = LAPB_DEFAULT_N2;
134	lapb->mode    = LAPB_DEFAULT_MODE;
135	lapb->window  = LAPB_DEFAULT_WINDOW;
136	lapb->state   = LAPB_STATE_0;
137	atomic_set(&lapb->refcnt, 1);
138out:
139	return lapb;
140}
141
142int lapb_register(struct net_device *dev, struct lapb_register_struct *callbacks)
143{
144	struct lapb_cb *lapb;
145	int rc = LAPB_BADTOKEN;
146
147	write_lock_bh(&lapb_list_lock);
148
149	lapb = __lapb_devtostruct(dev);
150	if (lapb) {
151		lapb_put(lapb);
152		goto out;
153	}
154
155	lapb = lapb_create_cb();
156	rc = LAPB_NOMEM;
157	if (!lapb)
158		goto out;
159
160	lapb->dev       = dev;
161	lapb->callbacks = *callbacks;
162
163	__lapb_insert_cb(lapb);
164
165	lapb_start_t1timer(lapb);
166
167	rc = LAPB_OK;
168out:
169	write_unlock_bh(&lapb_list_lock);
170	return rc;
171}
172
173int lapb_unregister(struct net_device *dev)
174{
175	struct lapb_cb *lapb;
176	int rc = LAPB_BADTOKEN;
177
178	write_lock_bh(&lapb_list_lock);
179	lapb = __lapb_devtostruct(dev);
180	if (!lapb)
181		goto out;
182
183	lapb_stop_t1timer(lapb);
184	lapb_stop_t2timer(lapb);
185
186	lapb_clear_queues(lapb);
187
188	__lapb_remove_cb(lapb);
189
190	lapb_put(lapb);
191	rc = LAPB_OK;
192out:
193	write_unlock_bh(&lapb_list_lock);
194	return rc;
195}
196
197int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
198{
199	int rc = LAPB_BADTOKEN;
200	struct lapb_cb *lapb = lapb_devtostruct(dev);
201
202	if (!lapb)
203		goto out;
204
205	parms->t1      = lapb->t1 / HZ;
206	parms->t2      = lapb->t2 / HZ;
207	parms->n2      = lapb->n2;
208	parms->n2count = lapb->n2count;
209	parms->state   = lapb->state;
210	parms->window  = lapb->window;
211	parms->mode    = lapb->mode;
212
213	if (!timer_pending(&lapb->t1timer))
214		parms->t1timer = 0;
215	else
216		parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
217
218	if (!timer_pending(&lapb->t2timer))
219		parms->t2timer = 0;
220	else
221		parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
222
223	lapb_put(lapb);
224	rc = LAPB_OK;
225out:
226	return rc;
227}
228
229int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
230{
231	int rc = LAPB_BADTOKEN;
232	struct lapb_cb *lapb = lapb_devtostruct(dev);
233
234	if (!lapb)
235		goto out;
236
237	rc = LAPB_INVALUE;
238	if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
239		goto out_put;
240
241	if (lapb->state == LAPB_STATE_0) {
242		if (parms->mode & LAPB_EXTENDED) {
243			if (parms->window < 1 || parms->window > 127)
244				goto out_put;
245		} else {
246			if (parms->window < 1 || parms->window > 7)
247				goto out_put;
248		}
249		lapb->mode    = parms->mode;
250		lapb->window  = parms->window;
251	}
252
253	lapb->t1    = parms->t1 * HZ;
254	lapb->t2    = parms->t2 * HZ;
255	lapb->n2    = parms->n2;
256
257	rc = LAPB_OK;
258out_put:
259	lapb_put(lapb);
260out:
261	return rc;
262}
263
264int lapb_connect_request(struct net_device *dev)
265{
266	struct lapb_cb *lapb = lapb_devtostruct(dev);
267	int rc = LAPB_BADTOKEN;
268
269	if (!lapb)
270		goto out;
271
272	rc = LAPB_OK;
273	if (lapb->state == LAPB_STATE_1)
274		goto out_put;
275
276	rc = LAPB_CONNECTED;
277	if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
278		goto out_put;
279
280	lapb_establish_data_link(lapb);
281
282#if LAPB_DEBUG > 0
283	printk(KERN_DEBUG "lapb: (%p) S0 -> S1\n", lapb->dev);
284#endif
285	lapb->state = LAPB_STATE_1;
286
287	rc = LAPB_OK;
288out_put:
289	lapb_put(lapb);
290out:
291	return rc;
292}
293
294int lapb_disconnect_request(struct net_device *dev)
295{
296	struct lapb_cb *lapb = lapb_devtostruct(dev);
297	int rc = LAPB_BADTOKEN;
298
299	if (!lapb)
300		goto out;
301
302	switch (lapb->state) {
303		case LAPB_STATE_0:
304			rc = LAPB_NOTCONNECTED;
305			goto out_put;
306
307		case LAPB_STATE_1:
308#if LAPB_DEBUG > 1
309			printk(KERN_DEBUG "lapb: (%p) S1 TX DISC(1)\n", lapb->dev);
310#endif
311#if LAPB_DEBUG > 0
312			printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n", lapb->dev);
313#endif
314			lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
315			lapb->state = LAPB_STATE_0;
316			lapb_start_t1timer(lapb);
317			rc = LAPB_NOTCONNECTED;
318			goto out_put;
319
320		case LAPB_STATE_2:
321			rc = LAPB_OK;
322			goto out_put;
323	}
324
325	lapb_clear_queues(lapb);
326	lapb->n2count = 0;
327	lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
328	lapb_start_t1timer(lapb);
329	lapb_stop_t2timer(lapb);
330	lapb->state = LAPB_STATE_2;
331
332#if LAPB_DEBUG > 1
333	printk(KERN_DEBUG "lapb: (%p) S3 DISC(1)\n", lapb->dev);
334#endif
335#if LAPB_DEBUG > 0
336	printk(KERN_DEBUG "lapb: (%p) S3 -> S2\n", lapb->dev);
337#endif
338
339	rc = LAPB_OK;
340out_put:
341	lapb_put(lapb);
342out:
343	return rc;
344}
345
346int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
347{
348	struct lapb_cb *lapb = lapb_devtostruct(dev);
349	int rc = LAPB_BADTOKEN;
350
351	if (!lapb)
352		goto out;
353
354	rc = LAPB_NOTCONNECTED;
355	if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
356		goto out_put;
357
358	skb_queue_tail(&lapb->write_queue, skb);
359	lapb_kick(lapb);
360	rc = LAPB_OK;
361out_put:
362	lapb_put(lapb);
363out:
364	return rc;
365}
366
367int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
368{
369	struct lapb_cb *lapb = lapb_devtostruct(dev);
370	int rc = LAPB_BADTOKEN;
371
372	if (lapb) {
373		lapb_data_input(lapb, skb);
374		lapb_put(lapb);
375		rc = LAPB_OK;
376	}
377
378	return rc;
379}
380
381void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
382{
383	if (lapb->callbacks.connect_confirmation)
384		lapb->callbacks.connect_confirmation(lapb->dev, reason);
385}
386
387void lapb_connect_indication(struct lapb_cb *lapb, int reason)
388{
389	if (lapb->callbacks.connect_indication)
390		lapb->callbacks.connect_indication(lapb->dev, reason);
391}
392
393void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
394{
395	if (lapb->callbacks.disconnect_confirmation)
396		lapb->callbacks.disconnect_confirmation(lapb->dev, reason);
397}
398
399void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
400{
401	if (lapb->callbacks.disconnect_indication)
402		lapb->callbacks.disconnect_indication(lapb->dev, reason);
403}
404
405int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
406{
407	if (lapb->callbacks.data_indication)
408		return lapb->callbacks.data_indication(lapb->dev, skb);
409
410	kfree_skb(skb);
411	return NET_RX_SUCCESS; /* For now; must be != NET_RX_DROP */
412}
413
414int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
415{
416	int used = 0;
417
418	if (lapb->callbacks.data_transmit) {
419		lapb->callbacks.data_transmit(lapb->dev, skb);
420		used = 1;
421	}
422
423	return used;
424}
425
426EXPORT_SYMBOL(lapb_register);
427EXPORT_SYMBOL(lapb_unregister);
428EXPORT_SYMBOL(lapb_getparms);
429EXPORT_SYMBOL(lapb_setparms);
430EXPORT_SYMBOL(lapb_connect_request);
431EXPORT_SYMBOL(lapb_disconnect_request);
432EXPORT_SYMBOL(lapb_data_request);
433EXPORT_SYMBOL(lapb_data_received);
434
435static int __init lapb_init(void)
436{
437	return 0;
438}
439
440static void __exit lapb_exit(void)
441{
442	WARN_ON(!list_empty(&lapb_list));
443}
444
445MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
446MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
447MODULE_LICENSE("GPL");
448
449module_init(lapb_init);
450module_exit(lapb_exit);
451