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