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
42 static LIST_HEAD(lapb_list);
43 static DEFINE_RWLOCK(lapb_list_lock);
44
45 /*
46 * Free an allocated lapb control block.
47 */
48 static void lapb_free_cb(struct lapb_cb *lapb)
49 {
50 kfree(lapb);
51 }
52
53 static __inline__ void lapb_hold(struct lapb_cb *lapb)
54 {
55 atomic_inc(&lapb->refcnt);
56 }
57
58 static __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 */
67 static 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 */
78 static void __lapb_insert_cb(struct lapb_cb *lapb)
79 {
80 list_add(&lapb->node, &lapb_list);
81 lapb_hold(lapb);
82 }
83
84 static 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
103 static 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 */
116 static 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);
137 out:
138 return lapb;
139 }
140
141 int 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;
167 out:
168 write_unlock_bh(&lapb_list_lock);
169 return rc;
170 }
171
172 int 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;
191 out:
192 write_unlock_bh(&lapb_list_lock);
193 return rc;
194 }
195
196 int 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;
224 out:
225 return rc;
226 }
227
228 int 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;
257 out_put:
258 lapb_put(lapb);
259 out:
260 return rc;
261 }
262
263 int 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;
287 out_put:
288 lapb_put(lapb);
289 out:
290 return rc;
291 }
292
293 int 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;
339 out_put:
340 lapb_put(lapb);
341 out:
342 return rc;
343 }
344
345 int 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;
360 out_put:
361 lapb_put(lapb);
362 out:
363 return rc;
364 }
365
366 int 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
380 void 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
386 void 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
392 void 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
398 void 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
404 int 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
413 int 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
425 EXPORT_SYMBOL(lapb_register);
426 EXPORT_SYMBOL(lapb_unregister);
427 EXPORT_SYMBOL(lapb_getparms);
428 EXPORT_SYMBOL(lapb_setparms);
429 EXPORT_SYMBOL(lapb_connect_request);
430 EXPORT_SYMBOL(lapb_disconnect_request);
431 EXPORT_SYMBOL(lapb_data_request);
432 EXPORT_SYMBOL(lapb_data_received);
433
434 static int __init lapb_init(void)
435 {
436 return 0;
437 }
438
439 static void __exit lapb_exit(void)
440 {
441 WARN_ON(!list_empty(&lapb_list));
442 }
443
444 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
445 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
446 MODULE_LICENSE("GPL");
447
448 module_init(lapb_init);
449 module_exit(lapb_exit);
450
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