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