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 <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  */
  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         refcount_inc(&lapb->refcnt);
  58 }
  59
  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  */
  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         refcount_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         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
 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
 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
 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
 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
 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
 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
 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 static int __init lapb_init(void)
 428 {
 429         return 0;
 430 }
 431
 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);