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
  77 /*
  78  *      Add a socket to the bound sockets list.
  79  */
  80 static void __lapb_insert_cb(struct lapb_cb *lapb)
  81 {
  82         list_add(&lapb->node, &lapb_list);
  83         lapb_hold(lapb);
  84 }
  85
  86 static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
  87 {
  88         struct list_head *entry;
  89         struct lapb_cb *lapb, *use = NULL;
  90
  91         list_for_each(entry, &lapb_list) {
  92                 lapb = list_entry(entry, struct lapb_cb, node);
  93                 if (lapb->dev == dev) {
  94                         use = lapb;
  95                         break;
  96                 }
  97         }
  98
  99         if (use)
 100                 lapb_hold(use);
 101
 102         return use;
 103 }
 104
 105 static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
 106 {
 107         struct lapb_cb *rc;
 108
 109         read_lock_bh(&lapb_list_lock);
 110         rc = __lapb_devtostruct(dev);
 111         read_unlock_bh(&lapb_list_lock);
 112
 113         return rc;
 114 }
 115 /*
 116  *      Create an empty LAPB control block.
 117  */
 118 static struct lapb_cb *lapb_create_cb(void)
 119 {
 120         struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);
 121
 122
 123         if (!lapb)
 124                 goto out;
 125
 126         skb_queue_head_init(&lapb->write_queue);
 127         skb_queue_head_init(&lapb->ack_queue);
 128
 129         init_timer(&lapb->t1timer);
 130         init_timer(&lapb->t2timer);
 131
 132         lapb->t1      = LAPB_DEFAULT_T1;
 133         lapb->t2      = LAPB_DEFAULT_T2;
 134         lapb->n2      = LAPB_DEFAULT_N2;
 135         lapb->mode    = LAPB_DEFAULT_MODE;
 136         lapb->window  = LAPB_DEFAULT_WINDOW;
 137         lapb->state   = LAPB_STATE_0;
 138         atomic_set(&lapb->refcnt, 1);
 139 out:
 140         return lapb;
 141 }
 142
 143 int lapb_register(struct net_device *dev,
 144                   const struct lapb_register_struct *callbacks)
 145 {
 146         struct lapb_cb *lapb;
 147         int rc = LAPB_BADTOKEN;
 148
 149         write_lock_bh(&lapb_list_lock);
 150
 151         lapb = __lapb_devtostruct(dev);
 152         if (lapb) {
 153                 lapb_put(lapb);
 154                 goto out;
 155         }
 156
 157         lapb = lapb_create_cb();
 158         rc = LAPB_NOMEM;
 159         if (!lapb)
 160                 goto out;
 161
 162         lapb->dev       = dev;
 163         lapb->callbacks = callbacks;
 164
 165         __lapb_insert_cb(lapb);
 166
 167         lapb_start_t1timer(lapb);
 168
 169         rc = LAPB_OK;
 170 out:
 171         write_unlock_bh(&lapb_list_lock);
 172         return rc;
 173 }
 174
 175 int lapb_unregister(struct net_device *dev)
 176 {
 177         struct lapb_cb *lapb;
 178         int rc = LAPB_BADTOKEN;
 179
 180         write_lock_bh(&lapb_list_lock);
 181         lapb = __lapb_devtostruct(dev);
 182         if (!lapb)
 183                 goto out;
 184
 185         lapb_stop_t1timer(lapb);
 186         lapb_stop_t2timer(lapb);
 187
 188         lapb_clear_queues(lapb);
 189
 190         __lapb_remove_cb(lapb);
 191
 192         lapb_put(lapb);
 193         rc = LAPB_OK;
 194 out:
 195         write_unlock_bh(&lapb_list_lock);
 196         return rc;
 197 }
 198
 199 int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
 200 {
 201         int rc = LAPB_BADTOKEN;
 202         struct lapb_cb *lapb = lapb_devtostruct(dev);
 203
 204         if (!lapb)
 205                 goto out;
 206
 207         parms->t1      = lapb->t1 / HZ;
 208         parms->t2      = lapb->t2 / HZ;
 209         parms->n2      = lapb->n2;
 210         parms->n2count = lapb->n2count;
 211         parms->state   = lapb->state;
 212         parms->window  = lapb->window;
 213         parms->mode    = lapb->mode;
 214
 215         if (!timer_pending(&lapb->t1timer))
 216                 parms->t1timer = 0;
 217         else
 218                 parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
 219
 220         if (!timer_pending(&lapb->t2timer))
 221                 parms->t2timer = 0;
 222         else
 223                 parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
 224
 225         lapb_put(lapb);
 226         rc = LAPB_OK;
 227 out:
 228         return rc;
 229 }
 230
 231 int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
 232 {
 233         int rc = LAPB_BADTOKEN;
 234         struct lapb_cb *lapb = lapb_devtostruct(dev);
 235
 236         if (!lapb)
 237                 goto out;
 238
 239         rc = LAPB_INVALUE;
 240         if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
 241                 goto out_put;
 242
 243         if (lapb->state == LAPB_STATE_0) {
 244                 if (parms->mode & LAPB_EXTENDED) {
 245                         if (parms->window < 1 || parms->window > 127)
 246                                 goto out_put;
 247                 } else {
 248                         if (parms->window < 1 || parms->window > 7)
 249                                 goto out_put;
 250                 }
 251                 lapb->mode    = parms->mode;
 252                 lapb->window  = parms->window;
 253         }
 254
 255         lapb->t1    = parms->t1 * HZ;
 256         lapb->t2    = parms->t2 * HZ;
 257         lapb->n2    = parms->n2;
 258
 259         rc = LAPB_OK;
 260 out_put:
 261         lapb_put(lapb);
 262 out:
 263         return rc;
 264 }
 265
 266 int lapb_connect_request(struct net_device *dev)
 267 {
 268         struct lapb_cb *lapb = lapb_devtostruct(dev);
 269         int rc = LAPB_BADTOKEN;
 270
 271         if (!lapb)
 272                 goto out;
 273
 274         rc = LAPB_OK;
 275         if (lapb->state == LAPB_STATE_1)
 276                 goto out_put;
 277
 278         rc = LAPB_CONNECTED;
 279         if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
 280                 goto out_put;
 281
 282         lapb_establish_data_link(lapb);
 283
 284         lapb_dbg(0, "(%p) S0 -> S1\n", lapb->dev);
 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                 lapb_dbg(1, "(%p) S1 TX DISC(1)\n", lapb->dev);
 309                 lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
 310                 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 311                 lapb->state = LAPB_STATE_0;
 312                 lapb_start_t1timer(lapb);
 313                 rc = LAPB_NOTCONNECTED;
 314                 goto out_put;
 315
 316         case LAPB_STATE_2:
 317                 rc = LAPB_OK;
 318                 goto out_put;
 319         }
 320
 321         lapb_clear_queues(lapb);
 322         lapb->n2count = 0;
 323         lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 324         lapb_start_t1timer(lapb);
 325         lapb_stop_t2timer(lapb);
 326         lapb->state = LAPB_STATE_2;
 327
 328         lapb_dbg(1, "(%p) S3 DISC(1)\n", lapb->dev);
 329         lapb_dbg(0, "(%p) S3 -> S2\n", lapb->dev);
 330
 331         rc = LAPB_OK;
 332 out_put:
 333         lapb_put(lapb);
 334 out:
 335         return rc;
 336 }
 337
 338 int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
 339 {
 340         struct lapb_cb *lapb = lapb_devtostruct(dev);
 341         int rc = LAPB_BADTOKEN;
 342
 343         if (!lapb)
 344                 goto out;
 345
 346         rc = LAPB_NOTCONNECTED;
 347         if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
 348                 goto out_put;
 349
 350         skb_queue_tail(&lapb->write_queue, skb);
 351         lapb_kick(lapb);
 352         rc = LAPB_OK;
 353 out_put:
 354         lapb_put(lapb);
 355 out:
 356         return rc;
 357 }
 358
 359 int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
 360 {
 361         struct lapb_cb *lapb = lapb_devtostruct(dev);
 362         int rc = LAPB_BADTOKEN;
 363
 364         if (lapb) {
 365                 lapb_data_input(lapb, skb);
 366                 lapb_put(lapb);
 367                 rc = LAPB_OK;
 368         }
 369
 370         return rc;
 371 }
 372
 373 void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
 374 {
 375         if (lapb->callbacks->connect_confirmation)
 376                 lapb->callbacks->connect_confirmation(lapb->dev, reason);
 377 }
 378
 379 void lapb_connect_indication(struct lapb_cb *lapb, int reason)
 380 {
 381         if (lapb->callbacks->connect_indication)
 382                 lapb->callbacks->connect_indication(lapb->dev, reason);
 383 }
 384
 385 void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
 386 {
 387         if (lapb->callbacks->disconnect_confirmation)
 388                 lapb->callbacks->disconnect_confirmation(lapb->dev, reason);
 389 }
 390
 391 void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
 392 {
 393         if (lapb->callbacks->disconnect_indication)
 394                 lapb->callbacks->disconnect_indication(lapb->dev, reason);
 395 }
 396
 397 int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
 398 {
 399         if (lapb->callbacks->data_indication)
 400                 return lapb->callbacks->data_indication(lapb->dev, skb);
 401
 402         kfree_skb(skb);
 403         return NET_RX_SUCCESS; /* For now; must be != NET_RX_DROP */
 404 }
 405
 406 int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
 407 {
 408         int used = 0;
 409
 410         if (lapb->callbacks->data_transmit) {
 411                 lapb->callbacks->data_transmit(lapb->dev, skb);
 412                 used = 1;
 413         }
 414
 415         return used;
 416 }
 417
 418 EXPORT_SYMBOL(lapb_register);
 419 EXPORT_SYMBOL(lapb_unregister);
 420 EXPORT_SYMBOL(lapb_getparms);
 421 EXPORT_SYMBOL(lapb_setparms);
 422 EXPORT_SYMBOL(lapb_connect_request);
 423 EXPORT_SYMBOL(lapb_disconnect_request);
 424 EXPORT_SYMBOL(lapb_data_request);
 425 EXPORT_SYMBOL(lapb_data_received);
 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);