File: /usr/src/linux/net/lapb/lapb_iface.c
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/sched.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 lapb_cb *volatile lapb_list /* = NULL initially */;
43
44 /*
45 * Free an allocated lapb control block. This is done to centralise
46 * the MOD count code.
47 */
48 static void lapb_free_cb(lapb_cb *lapb)
49 {
50 kfree(lapb);
51
52 MOD_DEC_USE_COUNT;
53 }
54
55 /*
56 * Socket removal during an interrupt is now safe.
57 */
58 static void lapb_remove_cb(lapb_cb *lapb)
59 {
60 lapb_cb *s;
61 unsigned long flags;
62
63 save_flags(flags); cli();
64
65 if ((s = lapb_list) == lapb) {
66 lapb_list = s->next;
67 restore_flags(flags);
68 return;
69 }
70
71 while (s != NULL && s->next != NULL) {
72 if (s->next == lapb) {
73 s->next = lapb->next;
74 restore_flags(flags);
75 return;
76 }
77
78 s = s->next;
79 }
80
81 restore_flags(flags);
82 }
83
84 /*
85 * Add a socket to the bound sockets list.
86 */
87 static void lapb_insert_cb(lapb_cb *lapb)
88 {
89 unsigned long flags;
90
91 save_flags(flags); cli();
92
93 lapb->next = lapb_list;
94 lapb_list = lapb;
95
96 restore_flags(flags);
97 }
98
99 /*
100 * Convert the integer token used by the device driver into a pointer
101 * to a LAPB control structure.
102 */
103 static lapb_cb *lapb_tokentostruct(void *token)
104 {
105 lapb_cb *lapb;
106
107 for (lapb = lapb_list; lapb != NULL; lapb = lapb->next)
108 if (lapb->token == token)
109 return lapb;
110
111 return NULL;
112 }
113
114 /*
115 * Create an empty LAPB control block.
116 */
117 static lapb_cb *lapb_create_cb(void)
118 {
119 lapb_cb *lapb;
120
121 if ((lapb = kmalloc(sizeof(*lapb), GFP_ATOMIC)) == NULL)
122 return NULL;
123
124 MOD_INC_USE_COUNT;
125
126 memset(lapb, 0x00, sizeof(*lapb));
127
128 skb_queue_head_init(&lapb->write_queue);
129 skb_queue_head_init(&lapb->ack_queue);
130
131 init_timer(&lapb->t1timer);
132 init_timer(&lapb->t2timer);
133
134 lapb->t1 = LAPB_DEFAULT_T1;
135 lapb->t2 = LAPB_DEFAULT_T2;
136 lapb->n2 = LAPB_DEFAULT_N2;
137 lapb->mode = LAPB_DEFAULT_MODE;
138 lapb->window = LAPB_DEFAULT_WINDOW;
139 lapb->state = LAPB_STATE_0;
140
141 return lapb;
142 }
143
144 int lapb_register(void *token, struct lapb_register_struct *callbacks)
145 {
146 lapb_cb *lapb;
147
148 if (lapb_tokentostruct(token) != NULL)
149 return LAPB_BADTOKEN;
150
151 if ((lapb = lapb_create_cb()) == NULL)
152 return LAPB_NOMEM;
153
154 lapb->token = token;
155 lapb->callbacks = *callbacks;
156
157 lapb_insert_cb(lapb);
158
159 lapb_start_t1timer(lapb);
160
161 return LAPB_OK;
162 }
163
164 int lapb_unregister(void *token)
165 {
166 lapb_cb *lapb;
167
168 if ((lapb = lapb_tokentostruct(token)) == NULL)
169 return LAPB_BADTOKEN;
170
171 lapb_stop_t1timer(lapb);
172 lapb_stop_t2timer(lapb);
173
174 lapb_clear_queues(lapb);
175
176 lapb_remove_cb(lapb);
177
178 lapb_free_cb(lapb);
179
180 return LAPB_OK;
181 }
182
183 int lapb_getparms(void *token, struct lapb_parms_struct *parms)
184 {
185 lapb_cb *lapb;
186
187 if ((lapb = lapb_tokentostruct(token)) == NULL)
188 return LAPB_BADTOKEN;
189
190 parms->t1 = lapb->t1 / HZ;
191 parms->t2 = lapb->t2 / HZ;
192 parms->n2 = lapb->n2;
193 parms->n2count = lapb->n2count;
194 parms->state = lapb->state;
195 parms->window = lapb->window;
196 parms->mode = lapb->mode;
197
198 if (!timer_pending(&lapb->t1timer))
199 parms->t1timer = 0;
200 else
201 parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
202
203 if (!timer_pending(&lapb->t2timer))
204 parms->t2timer = 0;
205 else
206 parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
207
208 return LAPB_OK;
209 }
210
211 int lapb_setparms(void *token, struct lapb_parms_struct *parms)
212 {
213 lapb_cb *lapb;
214
215 if ((lapb = lapb_tokentostruct(token)) == NULL)
216 return LAPB_BADTOKEN;
217
218 if (parms->t1 < 1)
219 return LAPB_INVALUE;
220
221 if (parms->t2 < 1)
222 return LAPB_INVALUE;
223
224 if (parms->n2 < 1)
225 return LAPB_INVALUE;
226
227 if (lapb->state == LAPB_STATE_0) {
228 if (parms->mode & LAPB_EXTENDED) {
229 if (parms->window < 1 || parms->window > 127)
230 return LAPB_INVALUE;
231 } else {
232 if (parms->window < 1 || parms->window > 7)
233 return LAPB_INVALUE;
234 }
235
236 lapb->mode = parms->mode;
237 lapb->window = parms->window;
238 }
239
240 lapb->t1 = parms->t1 * HZ;
241 lapb->t2 = parms->t2 * HZ;
242 lapb->n2 = parms->n2;
243
244 return LAPB_OK;
245 }
246
247 int lapb_connect_request(void *token)
248 {
249 lapb_cb *lapb;
250
251 if ((lapb = lapb_tokentostruct(token)) == NULL)
252 return LAPB_BADTOKEN;
253
254 switch (lapb->state) {
255 case LAPB_STATE_1:
256 return LAPB_OK;
257 case LAPB_STATE_3:
258 case LAPB_STATE_4:
259 return LAPB_CONNECTED;
260 }
261
262 lapb_establish_data_link(lapb);
263
264 #if LAPB_DEBUG > 0
265 printk(KERN_DEBUG "lapb: (%p) S0 -> S1\n", lapb->token);
266 #endif
267
268 lapb->state = LAPB_STATE_1;
269
270 return LAPB_OK;
271 }
272
273 int lapb_disconnect_request(void *token)
274 {
275 lapb_cb *lapb;
276
277 if ((lapb = lapb_tokentostruct(token)) == NULL)
278 return LAPB_BADTOKEN;
279
280 switch (lapb->state) {
281 case LAPB_STATE_0:
282 return LAPB_NOTCONNECTED;
283
284 case LAPB_STATE_1:
285 #if LAPB_DEBUG > 1
286 printk(KERN_DEBUG "lapb: (%p) S1 TX DISC(1)\n", lapb->token);
287 #endif
288 #if LAPB_DEBUG > 0
289 printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n", lapb->token);
290 #endif
291 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
292 lapb->state = LAPB_STATE_0;
293 lapb_start_t1timer(lapb);
294 return LAPB_NOTCONNECTED;
295
296 case LAPB_STATE_2:
297 return LAPB_OK;
298 }
299
300 lapb_clear_queues(lapb);
301 lapb->n2count = 0;
302 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
303 lapb_start_t1timer(lapb);
304 lapb_stop_t2timer(lapb);
305 lapb->state = LAPB_STATE_2;
306
307 #if LAPB_DEBUG > 1
308 printk(KERN_DEBUG "lapb: (%p) S3 DISC(1)\n", lapb->token);
309 #endif
310 #if LAPB_DEBUG > 0
311 printk(KERN_DEBUG "lapb: (%p) S3 -> S2\n", lapb->token);
312 #endif
313
314 return LAPB_OK;
315 }
316
317 int lapb_data_request(void *token, struct sk_buff *skb)
318 {
319 lapb_cb *lapb;
320
321 if ((lapb = lapb_tokentostruct(token)) == NULL)
322 return LAPB_BADTOKEN;
323
324 if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
325 return LAPB_NOTCONNECTED;
326
327 skb_queue_tail(&lapb->write_queue, skb);
328
329 lapb_kick(lapb);
330
331 return LAPB_OK;
332 }
333
334 int lapb_data_received(void *token, struct sk_buff *skb)
335 {
336 lapb_cb *lapb;
337
338 if ((lapb = lapb_tokentostruct(token)) == NULL)
339 return LAPB_BADTOKEN;
340
341 lapb_data_input(lapb, skb);
342
343 return LAPB_OK;
344 }
345
346 void lapb_connect_confirmation(lapb_cb *lapb, int reason)
347 {
348 if (lapb->callbacks.connect_confirmation != NULL)
349 (lapb->callbacks.connect_confirmation)(lapb->token, reason);
350 }
351
352 void lapb_connect_indication(lapb_cb *lapb, int reason)
353 {
354 if (lapb->callbacks.connect_indication != NULL)
355 (lapb->callbacks.connect_indication)(lapb->token, reason);
356 }
357
358 void lapb_disconnect_confirmation(lapb_cb *lapb, int reason)
359 {
360 if (lapb->callbacks.disconnect_confirmation != NULL)
361 (lapb->callbacks.disconnect_confirmation)(lapb->token, reason);
362 }
363
364 void lapb_disconnect_indication(lapb_cb *lapb, int reason)
365 {
366 if (lapb->callbacks.disconnect_indication != NULL)
367 (lapb->callbacks.disconnect_indication)(lapb->token, reason);
368 }
369
370 int lapb_data_indication(lapb_cb *lapb, struct sk_buff *skb)
371 {
372 if (lapb->callbacks.data_indication != NULL) {
373 return (lapb->callbacks.data_indication)(lapb->token, skb);
374 }
375 kfree_skb(skb);
376 return NET_RX_CN_HIGH; /* For now; must be != NET_RX_DROP */
377 }
378
379 int lapb_data_transmit(lapb_cb *lapb, struct sk_buff *skb)
380 {
381 int used = 0;
382
383 if (lapb->callbacks.data_transmit != NULL) {
384 (lapb->callbacks.data_transmit)(lapb->token, skb);
385 used = 1;
386 }
387
388 return used;
389 }
390
391 EXPORT_SYMBOL(lapb_register);
392 EXPORT_SYMBOL(lapb_unregister);
393 EXPORT_SYMBOL(lapb_getparms);
394 EXPORT_SYMBOL(lapb_setparms);
395 EXPORT_SYMBOL(lapb_connect_request);
396 EXPORT_SYMBOL(lapb_disconnect_request);
397 EXPORT_SYMBOL(lapb_data_request);
398 EXPORT_SYMBOL(lapb_data_received);
399
400 static char banner[] __initdata = KERN_INFO "NET4: LAPB for Linux. Version 0.01 for NET4.0\n";
401
402 static int __init lapb_init(void)
403 {
404 printk(banner);
405 return 0;
406 }
407
408 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
409 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
410
411 module_init(lapb_init);
412