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/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,
 143                   const struct lapb_register_struct *callbacks)
 144 {
 145         struct lapb_cb *lapb;
 146         int rc = LAPB_BADTOKEN;
 147
 148         write_lock_bh(&lapb_list_lock);
 149
 150         lapb = __lapb_devtostruct(dev);
 151         if (lapb) {
 152                 lapb_put(lapb);
 153                 goto out;
 154         }
 155
 156         lapb = lapb_create_cb();
 157         rc = LAPB_NOMEM;
 158         if (!lapb)
 159                 goto out;
 160
 161         lapb->dev       = dev;
 162         lapb->callbacks = callbacks;
 163
 164         __lapb_insert_cb(lapb);
 165
 166         lapb_start_t1timer(lapb);
 167
 168         rc = LAPB_OK;
 169 out:
 170         write_unlock_bh(&lapb_list_lock);
 171         return rc;
 172 }
 173
 174 int lapb_unregister(struct net_device *dev)
 175 {
 176         struct lapb_cb *lapb;
 177         int rc = LAPB_BADTOKEN;
 178
 179         write_lock_bh(&lapb_list_lock);
 180         lapb = __lapb_devtostruct(dev);
 181         if (!lapb)
 182                 goto out;
 183
 184         lapb_stop_t1timer(lapb);
 185         lapb_stop_t2timer(lapb);
 186
 187         lapb_clear_queues(lapb);
 188
 189         __lapb_remove_cb(lapb);
 190
 191         lapb_put(lapb);
 192         rc = LAPB_OK;
 193 out:
 194         write_unlock_bh(&lapb_list_lock);
 195         return rc;
 196 }
 197
 198 int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
 199 {
 200         int rc = LAPB_BADTOKEN;
 201         struct lapb_cb *lapb = lapb_devtostruct(dev);
 202
 203         if (!lapb)
 204                 goto out;
 205
 206         parms->t1      = lapb->t1 / HZ;
 207         parms->t2      = lapb->t2 / HZ;
 208         parms->n2      = lapb->n2;
 209         parms->n2count = lapb->n2count;
 210         parms->state   = lapb->state;
 211         parms->window  = lapb->window;
 212         parms->mode    = lapb->mode;
 213
 214         if (!timer_pending(&lapb->t1timer))
 215                 parms->t1timer = 0;
 216         else
 217                 parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
 218
 219         if (!timer_pending(&lapb->t2timer))
 220                 parms->t2timer = 0;
 221         else
 222                 parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
 223
 224         lapb_put(lapb);
 225         rc = LAPB_OK;
 226 out:
 227         return rc;
 228 }
 229
 230 int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
 231 {
 232         int rc = LAPB_BADTOKEN;
 233         struct lapb_cb *lapb = lapb_devtostruct(dev);
 234
 235         if (!lapb)
 236                 goto out;
 237
 238         rc = LAPB_INVALUE;
 239         if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
 240                 goto out_put;
 241
 242         if (lapb->state == LAPB_STATE_0) {
 243                 if (parms->mode & LAPB_EXTENDED) {
 244                         if (parms->window < 1 || parms->window > 127)
 245                                 goto out_put;
 246                 } else {
 247                         if (parms->window < 1 || parms->window > 7)
 248                                 goto out_put;
 249                 }
 250                 lapb->mode    = parms->mode;
 251                 lapb->window  = parms->window;
 252         }
 253
 254         lapb->t1    = parms->t1 * HZ;
 255         lapb->t2    = parms->t2 * HZ;
 256         lapb->n2    = parms->n2;
 257
 258         rc = LAPB_OK;
 259 out_put:
 260         lapb_put(lapb);
 261 out:
 262         return rc;
 263 }
 264
 265 int lapb_connect_request(struct net_device *dev)
 266 {
 267         struct lapb_cb *lapb = lapb_devtostruct(dev);
 268         int rc = LAPB_BADTOKEN;
 269
 270         if (!lapb)
 271                 goto out;
 272
 273         rc = LAPB_OK;
 274         if (lapb->state == LAPB_STATE_1)
 275                 goto out_put;
 276
 277         rc = LAPB_CONNECTED;
 278         if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
 279                 goto out_put;
 280
 281         lapb_establish_data_link(lapb);
 282
 283 #if LAPB_DEBUG > 0
 284         printk(KERN_DEBUG "lapb: (%p) S0 -> S1\n", lapb->dev);
 285 #endif
 286         lapb->state = LAPB_STATE_1;
 287
 288         rc = LAPB_OK;
 289 out_put:
 290         lapb_put(lapb);
 291 out:
 292         return rc;
 293 }
 294
 295 int lapb_disconnect_request(struct net_device *dev)
 296 {
 297         struct lapb_cb *lapb = lapb_devtostruct(dev);
 298         int rc = LAPB_BADTOKEN;
 299
 300         if (!lapb)
 301                 goto out;
 302
 303         switch (lapb->state) {
 304         case LAPB_STATE_0:
 305                 rc = LAPB_NOTCONNECTED;
 306                 goto out_put;
 307
 308         case LAPB_STATE_1:
 309 #if LAPB_DEBUG > 1
 310                 printk(KERN_DEBUG "lapb: (%p) S1 TX DISC(1)\n", lapb->dev);
 311 #endif
 312 #if LAPB_DEBUG > 0
 313                 printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n", lapb->dev);
 314 #endif
 315                 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 316                 lapb->state = LAPB_STATE_0;
 317                 lapb_start_t1timer(lapb);
 318                 rc = LAPB_NOTCONNECTED;
 319                 goto out_put;
 320
 321         case LAPB_STATE_2:
 322                 rc = LAPB_OK;
 323                 goto out_put;
 324         }
 325
 326         lapb_clear_queues(lapb);
 327         lapb->n2count = 0;
 328         lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 329         lapb_start_t1timer(lapb);
 330         lapb_stop_t2timer(lapb);
 331         lapb->state = LAPB_STATE_2;
 332
 333 #if LAPB_DEBUG > 1
 334         printk(KERN_DEBUG "lapb: (%p) S3 DISC(1)\n", lapb->dev);
 335 #endif
 336 #if LAPB_DEBUG > 0
 337         printk(KERN_DEBUG "lapb: (%p) S3 -> S2\n", lapb->dev);
 338 #endif
 339
 340         rc = LAPB_OK;
 341 out_put:
 342         lapb_put(lapb);
 343 out:
 344         return rc;
 345 }
 346
 347 int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
 348 {
 349         struct lapb_cb *lapb = lapb_devtostruct(dev);
 350         int rc = LAPB_BADTOKEN;
 351
 352         if (!lapb)
 353                 goto out;
 354
 355         rc = LAPB_NOTCONNECTED;
 356         if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
 357                 goto out_put;
 358
 359         skb_queue_tail(&lapb->write_queue, skb);
 360         lapb_kick(lapb);
 361         rc = LAPB_OK;
 362 out_put:
 363         lapb_put(lapb);
 364 out:
 365         return rc;
 366 }
 367
 368 int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
 369 {
 370         struct lapb_cb *lapb = lapb_devtostruct(dev);
 371         int rc = LAPB_BADTOKEN;
 372
 373         if (lapb) {
 374                 lapb_data_input(lapb, skb);
 375                 lapb_put(lapb);
 376                 rc = LAPB_OK;
 377         }
 378
 379         return rc;
 380 }
 381
 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
 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
 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
 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
 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
 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
 427 EXPORT_SYMBOL(lapb_register);
 428 EXPORT_SYMBOL(lapb_unregister);
 429 EXPORT_SYMBOL(lapb_getparms);
 430 EXPORT_SYMBOL(lapb_setparms);
 431 EXPORT_SYMBOL(lapb_connect_request);
 432 EXPORT_SYMBOL(lapb_disconnect_request);
 433 EXPORT_SYMBOL(lapb_data_request);
 434 EXPORT_SYMBOL(lapb_data_received);
 435
 436 static int __init lapb_init(void)
 437 {
 438         return 0;
 439 }
 440
 441 static void __exit lapb_exit(void)
 442 {
 443         WARN_ON(!list_empty(&lapb_list));
 444 }
 445
 446 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
 447 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
 448 MODULE_LICENSE("GPL");
 449
 450 module_init(lapb_init);
 451 module_exit(lapb_exit);