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   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 <asm/system.h>
  36 #include <linux/fcntl.h>
  37 #include <linux/mm.h>
  38 #include <linux/interrupt.h>
  39 #include <linux/stat.h>
  40 #include <linux/init.h>
  41 #include <net/lapb.h>
  42
  43 static LIST_HEAD(lapb_list);
  44 static DEFINE_RWLOCK(lapb_list_lock);
  45
  46 /*
  47  *      Free an allocated lapb control block.
  48  */
  49 static void lapb_free_cb(struct lapb_cb *lapb)
  50 {
  51         kfree(lapb);
  52 }
  53
  54 static __inline__ void lapb_hold(struct lapb_cb *lapb)
  55 {
  56         atomic_inc(&lapb->refcnt);
  57 }
  58
  59 static __inline__ void lapb_put(struct lapb_cb *lapb)
  60 {
  61         if (atomic_dec_and_test(&lapb->refcnt))
  62                 lapb_free_cb(lapb);
  63 }
  64
  65 /*
  66  *      Socket removal during an interrupt is now safe.
  67  */
  68 static void __lapb_remove_cb(struct lapb_cb *lapb)
  69 {
  70         if (lapb->node.next) {
  71                 list_del(&lapb->node);
  72                 lapb_put(lapb);
  73         }
  74 }
  75
  76 /*
  77  *      Add a socket to the bound sockets list.
  78  */
  79 static void __lapb_insert_cb(struct lapb_cb *lapb)
  80 {
  81         list_add(&lapb->node, &lapb_list);
  82         lapb_hold(lapb);
  83 }
  84
  85 static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
  86 {
  87         struct list_head *entry;
  88         struct lapb_cb *lapb, *use = NULL;
  89
  90         list_for_each(entry, &lapb_list) {
  91                 lapb = list_entry(entry, struct lapb_cb, node);
  92                 if (lapb->dev == dev) {
  93                         use = lapb;
  94                         break;
  95                 }
  96         }
  97
  98         if (use)
  99                 lapb_hold(use);
 100
 101         return use;
 102 }
 103
 104 static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
 105 {
 106         struct lapb_cb *rc;
 107
 108         read_lock_bh(&lapb_list_lock);
 109         rc = __lapb_devtostruct(dev);
 110         read_unlock_bh(&lapb_list_lock);
 111
 112         return rc;
 113 }
 114 /*
 115  *      Create an empty LAPB control block.
 116  */
 117 static struct lapb_cb *lapb_create_cb(void)
 118 {
 119         struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);
 120
 121
 122         if (!lapb)
 123                 goto out;
 124
 125         skb_queue_head_init(&lapb->write_queue);
 126         skb_queue_head_init(&lapb->ack_queue);
 127
 128         init_timer(&lapb->t1timer);
 129         init_timer(&lapb->t2timer);
 130
 131         lapb->t1      = LAPB_DEFAULT_T1;
 132         lapb->t2      = LAPB_DEFAULT_T2;
 133         lapb->n2      = LAPB_DEFAULT_N2;
 134         lapb->mode    = LAPB_DEFAULT_MODE;
 135         lapb->window  = LAPB_DEFAULT_WINDOW;
 136         lapb->state   = LAPB_STATE_0;
 137         atomic_set(&lapb->refcnt, 1);
 138 out:
 139         return lapb;
 140 }
 141
 142 int lapb_register(struct net_device *dev, 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 435 static int __init lapb_init(void)
 436 {
 437         return 0;
 438 }
 439
 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);