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 #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 <asm/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  */
  50 static void lapb_free_cb(struct lapb_cb *lapb)
  51 {
  52         kfree(lapb);
  53 }
  54
  55 static __inline__ void lapb_hold(struct lapb_cb *lapb)
  56 {
  57         atomic_inc(&lapb->refcnt);
  58 }
  59
  60 static __inline__ void lapb_put(struct lapb_cb *lapb)
  61 {
  62         if (atomic_dec_and_test(&lapb->refcnt))
  63                 lapb_free_cb(lapb);
  64 }
  65
  66 /*
  67  *      Socket removal during an interrupt is now safe.
  68  */
  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  */
  81 static void __lapb_insert_cb(struct lapb_cb *lapb)
  82 {
  83         list_add(&lapb->node, &lapb_list);
  84         lapb_hold(lapb);
  85 }
  86
  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
 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  */
 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         init_timer(&lapb->t1timer);
 131         init_timer(&lapb->t2timer);
 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         atomic_set(&lapb->refcnt, 1);
 140 out:
 141         return lapb;
 142 }
 143
 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
 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
 186         lapb_stop_t1timer(lapb);
 187         lapb_stop_t2timer(lapb);
 188
 189         lapb_clear_queues(lapb);
 190
 191         __lapb_remove_cb(lapb);
 192
 193         lapb_put(lapb);
 194         rc = LAPB_OK;
 195 out:
 196         write_unlock_bh(&lapb_list_lock);
 197         return rc;
 198 }
 199 EXPORT_SYMBOL(lapb_unregister);
 200
 201 int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
 202 {
 203         int rc = LAPB_BADTOKEN;
 204         struct lapb_cb *lapb = lapb_devtostruct(dev);
 205
 206         if (!lapb)
 207                 goto out;
 208
 209         parms->t1      = lapb->t1 / HZ;
 210         parms->t2      = lapb->t2 / HZ;
 211         parms->n2      = lapb->n2;
 212         parms->n2count = lapb->n2count;
 213         parms->state   = lapb->state;
 214         parms->window  = lapb->window;
 215         parms->mode    = lapb->mode;
 216
 217         if (!timer_pending(&lapb->t1timer))
 218                 parms->t1timer = 0;
 219         else
 220                 parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
 221
 222         if (!timer_pending(&lapb->t2timer))
 223                 parms->t2timer = 0;
 224         else
 225                 parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
 226
 227         lapb_put(lapb);
 228         rc = LAPB_OK;
 229 out:
 230         return rc;
 231 }
 232 EXPORT_SYMBOL(lapb_getparms);
 233
 234 int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
 235 {
 236         int rc = LAPB_BADTOKEN;
 237         struct lapb_cb *lapb = lapb_devtostruct(dev);
 238
 239         if (!lapb)
 240                 goto out;
 241
 242         rc = LAPB_INVALUE;
 243         if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
 244                 goto out_put;
 245
 246         if (lapb->state == LAPB_STATE_0) {
 247                 if (parms->mode & LAPB_EXTENDED) {
 248                         if (parms->window < 1 || parms->window > 127)
 249                                 goto out_put;
 250                 } else {
 251                         if (parms->window < 1 || parms->window > 7)
 252                                 goto out_put;
 253                 }
 254                 lapb->mode    = parms->mode;
 255                 lapb->window  = parms->window;
 256         }
 257
 258         lapb->t1    = parms->t1 * HZ;
 259         lapb->t2    = parms->t2 * HZ;
 260         lapb->n2    = parms->n2;
 261
 262         rc = LAPB_OK;
 263 out_put:
 264         lapb_put(lapb);
 265 out:
 266         return rc;
 267 }
 268 EXPORT_SYMBOL(lapb_setparms);
 269
 270 int lapb_connect_request(struct net_device *dev)
 271 {
 272         struct lapb_cb *lapb = lapb_devtostruct(dev);
 273         int rc = LAPB_BADTOKEN;
 274
 275         if (!lapb)
 276                 goto out;
 277
 278         rc = LAPB_OK;
 279         if (lapb->state == LAPB_STATE_1)
 280                 goto out_put;
 281
 282         rc = LAPB_CONNECTED;
 283         if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
 284                 goto out_put;
 285
 286         lapb_establish_data_link(lapb);
 287
 288         lapb_dbg(0, "(%p) S0 -> S1\n", lapb->dev);
 289         lapb->state = LAPB_STATE_1;
 290
 291         rc = LAPB_OK;
 292 out_put:
 293         lapb_put(lapb);
 294 out:
 295         return rc;
 296 }
 297 EXPORT_SYMBOL(lapb_connect_request);
 298
 299 int lapb_disconnect_request(struct net_device *dev)
 300 {
 301         struct lapb_cb *lapb = lapb_devtostruct(dev);
 302         int rc = LAPB_BADTOKEN;
 303
 304         if (!lapb)
 305                 goto out;
 306
 307         switch (lapb->state) {
 308         case LAPB_STATE_0:
 309                 rc = LAPB_NOTCONNECTED;
 310                 goto out_put;
 311
 312         case LAPB_STATE_1:
 313                 lapb_dbg(1, "(%p) S1 TX DISC(1)\n", lapb->dev);
 314                 lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
 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         lapb_dbg(1, "(%p) S3 DISC(1)\n", lapb->dev);
 334         lapb_dbg(0, "(%p) S3 -> S2\n", lapb->dev);
 335
 336         rc = LAPB_OK;
 337 out_put:
 338         lapb_put(lapb);
 339 out:
 340         return rc;
 341 }
 342 EXPORT_SYMBOL(lapb_disconnect_request);
 343
 344 int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
 345 {
 346         struct lapb_cb *lapb = lapb_devtostruct(dev);
 347         int rc = LAPB_BADTOKEN;
 348
 349         if (!lapb)
 350                 goto out;
 351
 352         rc = LAPB_NOTCONNECTED;
 353         if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
 354                 goto out_put;
 355
 356         skb_queue_tail(&lapb->write_queue, skb);
 357         lapb_kick(lapb);
 358         rc = LAPB_OK;
 359 out_put:
 360         lapb_put(lapb);
 361 out:
 362         return rc;
 363 }
 364 EXPORT_SYMBOL(lapb_data_request);
 365
 366 int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
 367 {
 368         struct lapb_cb *lapb = lapb_devtostruct(dev);
 369         int rc = LAPB_BADTOKEN;
 370
 371         if (lapb) {
 372                 lapb_data_input(lapb, skb);
 373                 lapb_put(lapb);
 374                 rc = LAPB_OK;
 375         }
 376
 377         return rc;
 378 }
 379 EXPORT_SYMBOL(lapb_data_received);
 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 static int __init lapb_init(void)
 427 {
 428         return 0;
 429 }
 430
 431 static void __exit lapb_exit(void)
 432 {
 433         WARN_ON(!list_empty(&lapb_list));
 434 }
 435
 436 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
 437 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
 438 MODULE_LICENSE("GPL");
 439
 440 module_init(lapb_init);
 441 module_exit(lapb_exit);