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 <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 */
lapb_free_cb(struct lapb_cb * lapb)48 static void lapb_free_cb(struct lapb_cb *lapb)
49 {
50 kfree(lapb);
51 }
52
lapb_hold(struct lapb_cb * lapb)53 static __inline__ void lapb_hold(struct lapb_cb *lapb)
54 {
55 atomic_inc(&lapb->refcnt);
56 }
57
lapb_put(struct lapb_cb * lapb)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 */
__lapb_remove_cb(struct lapb_cb * lapb)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 */
__lapb_insert_cb(struct lapb_cb * lapb)78 static void __lapb_insert_cb(struct lapb_cb *lapb)
79 {
80 list_add(&lapb->node, &lapb_list);
81 lapb_hold(lapb);
82 }
83
__lapb_devtostruct(struct net_device * dev)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
lapb_devtostruct(struct net_device * dev)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 */
lapb_create_cb(void)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
lapb_register(struct net_device * dev,const struct lapb_register_struct * callbacks)141 int lapb_register(struct net_device *dev,
142 const 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;
168 out:
169 write_unlock_bh(&lapb_list_lock);
170 return rc;
171 }
172
lapb_unregister(struct net_device * dev)173 int 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;
192 out:
193 write_unlock_bh(&lapb_list_lock);
194 return rc;
195 }
196
lapb_getparms(struct net_device * dev,struct lapb_parms_struct * parms)197 int 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;
225 out:
226 return rc;
227 }
228
lapb_setparms(struct net_device * dev,struct lapb_parms_struct * parms)229 int 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;
258 out_put:
259 lapb_put(lapb);
260 out:
261 return rc;
262 }
263
lapb_connect_request(struct net_device * dev)264 int 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;
288 out_put:
289 lapb_put(lapb);
290 out:
291 return rc;
292 }
293
lapb_disconnect_request(struct net_device * dev)294 int 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;
340 out_put:
341 lapb_put(lapb);
342 out:
343 return rc;
344 }
345
lapb_data_request(struct net_device * dev,struct sk_buff * skb)346 int 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;
361 out_put:
362 lapb_put(lapb);
363 out:
364 return rc;
365 }
366
lapb_data_received(struct net_device * dev,struct sk_buff * skb)367 int 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
lapb_connect_confirmation(struct lapb_cb * lapb,int reason)381 void 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
lapb_connect_indication(struct lapb_cb * lapb,int reason)387 void 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
lapb_disconnect_confirmation(struct lapb_cb * lapb,int reason)393 void 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
lapb_disconnect_indication(struct lapb_cb * lapb,int reason)399 void 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
lapb_data_indication(struct lapb_cb * lapb,struct sk_buff * skb)405 int 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
lapb_data_transmit(struct lapb_cb * lapb,struct sk_buff * skb)414 int 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
426 EXPORT_SYMBOL(lapb_register);
427 EXPORT_SYMBOL(lapb_unregister);
428 EXPORT_SYMBOL(lapb_getparms);
429 EXPORT_SYMBOL(lapb_setparms);
430 EXPORT_SYMBOL(lapb_connect_request);
431 EXPORT_SYMBOL(lapb_disconnect_request);
432 EXPORT_SYMBOL(lapb_data_request);
433 EXPORT_SYMBOL(lapb_data_received);
434
lapb_init(void)435 static int __init lapb_init(void)
436 {
437 return 0;
438 }
439
lapb_exit(void)440 static void __exit lapb_exit(void)
441 {
442 WARN_ON(!list_empty(&lapb_list));
443 }
444
445 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
446 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
447 MODULE_LICENSE("GPL");
448
449 module_init(lapb_init);
450 module_exit(lapb_exit);
451