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 <net/sock.h>
  33 #include <asm/uaccess.h>
  34 #include <asm/system.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/mm.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/stat.h>
  39 #include <linux/init.h>
  40 #include <net/lapb.h>
  41
  42 static struct list_head lapb_list = LIST_HEAD_INIT(lapb_list);
  43 static DEFINE_RWLOCK(lapb_list_lock);
  44
  45 /*
  46  *      Free an allocated lapb control block.
  47  */
  48 static void lapb_free_cb(struct lapb_cb *lapb)
  49 {
  50         kfree(lapb);
  51 }
  52
  53 static __inline__ void lapb_hold(struct lapb_cb *lapb)
  54 {
  55         atomic_inc(&lapb->refcnt);
  56 }
  57
  58 static __inline__ void lapb_put(struct lapb_cb *lapb)
  59 {
  60         if (atomic_dec_and_test(&lapb->refcnt))
  61                 lapb_free_cb(lapb);
  62 }
  63
  64 /*
  65  *      Socket removal during an interrupt is now safe.
  66  */
  67 static void __lapb_remove_cb(struct lapb_cb *lapb)
  68 {
  69         if (lapb->node.next) {
  70                 list_del(&lapb->node);
  71                 lapb_put(lapb);
  72         }
  73 }
  74
  75 /*
  76  *      Add a socket to the bound sockets list.
  77  */
  78 static void __lapb_insert_cb(struct lapb_cb *lapb)
  79 {
  80         list_add(&lapb->node, &lapb_list);
  81         lapb_hold(lapb);
  82 }
  83
  84 static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
  85 {
  86         struct list_head *entry;
  87         struct lapb_cb *lapb, *use = NULL;
  88
  89         list_for_each(entry, &lapb_list) {
  90                 lapb = list_entry(entry, struct lapb_cb, node);
  91                 if (lapb->dev == dev) {
  92                         use = lapb;
  93                         break;
  94                 }
  95         }
  96
  97         if (use)
  98                 lapb_hold(use);
  99
 100         return use;
 101 }
 102
 103 static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
 104 {
 105         struct lapb_cb *rc;
 106
 107         read_lock_bh(&lapb_list_lock);
 108         rc = __lapb_devtostruct(dev);
 109         read_unlock_bh(&lapb_list_lock);
 110
 111         return rc;
 112 }
 113 /*
 114  *      Create an empty LAPB control block.
 115  */
 116 static struct lapb_cb *lapb_create_cb(void)
 117 {
 118         struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);
 119
 120
 121         if (!lapb)
 122                 goto out;
 123
 124         skb_queue_head_init(&lapb->write_queue);
 125         skb_queue_head_init(&lapb->ack_queue);
 126
 127         init_timer(&lapb->t1timer);
 128         init_timer(&lapb->t2timer);
 129
 130         lapb->t1      = LAPB_DEFAULT_T1;
 131         lapb->t2      = LAPB_DEFAULT_T2;
 132         lapb->n2      = LAPB_DEFAULT_N2;
 133         lapb->mode    = LAPB_DEFAULT_MODE;
 134         lapb->window  = LAPB_DEFAULT_WINDOW;
 135         lapb->state   = LAPB_STATE_0;
 136         atomic_set(&lapb->refcnt, 1);
 137 out:
 138         return lapb;
 139 }
 140
 141 int lapb_register(struct net_device *dev, struct lapb_register_struct *callbacks)
 142 {
 143         struct lapb_cb *lapb;
 144         int rc = LAPB_BADTOKEN;
 145
 146         write_lock_bh(&lapb_list_lock);
 147
 148         lapb = __lapb_devtostruct(dev);
 149         if (lapb) {
 150                 lapb_put(lapb);
 151                 goto out;
 152         }
 153
 154         lapb = lapb_create_cb();
 155         rc = LAPB_NOMEM;
 156         if (!lapb)
 157                 goto out;
 158
 159         lapb->dev       = dev;
 160         lapb->callbacks = *callbacks;
 161
 162         __lapb_insert_cb(lapb);
 163
 164         lapb_start_t1timer(lapb);
 165
 166         rc = LAPB_OK;
 167 out:
 168         write_unlock_bh(&lapb_list_lock);
 169         return rc;
 170 }
 171
 172 int lapb_unregister(struct net_device *dev)
 173 {
 174         struct lapb_cb *lapb;
 175         int rc = LAPB_BADTOKEN;
 176
 177         write_lock_bh(&lapb_list_lock);
 178         lapb = __lapb_devtostruct(dev);
 179         if (!lapb)
 180                 goto out;
 181
 182         lapb_stop_t1timer(lapb);
 183         lapb_stop_t2timer(lapb);
 184
 185         lapb_clear_queues(lapb);
 186
 187         __lapb_remove_cb(lapb);
 188
 189         lapb_put(lapb);
 190         rc = LAPB_OK;
 191 out:
 192         write_unlock_bh(&lapb_list_lock);
 193         return rc;
 194 }
 195
 196 int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
 197 {
 198         int rc = LAPB_BADTOKEN;
 199         struct lapb_cb *lapb = lapb_devtostruct(dev);
 200
 201         if (!lapb)
 202                 goto out;
 203
 204         parms->t1      = lapb->t1 / HZ;
 205         parms->t2      = lapb->t2 / HZ;
 206         parms->n2      = lapb->n2;
 207         parms->n2count = lapb->n2count;
 208         parms->state   = lapb->state;
 209         parms->window  = lapb->window;
 210         parms->mode    = lapb->mode;
 211
 212         if (!timer_pending(&lapb->t1timer))
 213                 parms->t1timer = 0;
 214         else
 215                 parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
 216
 217         if (!timer_pending(&lapb->t2timer))
 218                 parms->t2timer = 0;
 219         else
 220                 parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
 221
 222         lapb_put(lapb);
 223         rc = LAPB_OK;
 224 out:
 225         return rc;
 226 }
 227
 228 int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
 229 {
 230         int rc = LAPB_BADTOKEN;
 231         struct lapb_cb *lapb = lapb_devtostruct(dev);
 232
 233         if (!lapb)
 234                 goto out;
 235
 236         rc = LAPB_INVALUE;
 237         if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
 238                 goto out_put;
 239
 240         if (lapb->state == LAPB_STATE_0) {
 241                 if (parms->mode & LAPB_EXTENDED) {
 242                         if (parms->window < 1 || parms->window > 127)
 243                                 goto out_put;
 244                 } else {
 245                         if (parms->window < 1 || parms->window > 7)
 246                                 goto out_put;
 247                 }
 248                 lapb->mode    = parms->mode;
 249                 lapb->window  = parms->window;
 250         }
 251
 252         lapb->t1    = parms->t1 * HZ;
 253         lapb->t2    = parms->t2 * HZ;
 254         lapb->n2    = parms->n2;
 255
 256         rc = LAPB_OK;
 257 out_put:
 258         lapb_put(lapb);
 259 out:
 260         return rc;
 261 }
 262
 263 int lapb_connect_request(struct net_device *dev)
 264 {
 265         struct lapb_cb *lapb = lapb_devtostruct(dev);
 266         int rc = LAPB_BADTOKEN;
 267
 268         if (!lapb)
 269                 goto out;
 270
 271         rc = LAPB_OK;
 272         if (lapb->state == LAPB_STATE_1)
 273                 goto out_put;
 274
 275         rc = LAPB_CONNECTED;
 276         if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
 277                 goto out_put;
 278
 279         lapb_establish_data_link(lapb);
 280
 281 #if LAPB_DEBUG > 0
 282         printk(KERN_DEBUG "lapb: (%p) S0 -> S1\n", lapb->dev);
 283 #endif
 284         lapb->state = LAPB_STATE_1;
 285
 286         rc = LAPB_OK;
 287 out_put:
 288         lapb_put(lapb);
 289 out:
 290         return rc;
 291 }
 292
 293 int lapb_disconnect_request(struct net_device *dev)
 294 {
 295         struct lapb_cb *lapb = lapb_devtostruct(dev);
 296         int rc = LAPB_BADTOKEN;
 297
 298         if (!lapb)
 299                 goto out;
 300
 301         switch (lapb->state) {
 302                 case LAPB_STATE_0:
 303                         rc = LAPB_NOTCONNECTED;
 304                         goto out_put;
 305
 306                 case LAPB_STATE_1:
 307 #if LAPB_DEBUG > 1
 308                         printk(KERN_DEBUG "lapb: (%p) S1 TX DISC(1)\n", lapb->dev);
 309 #endif
 310 #if LAPB_DEBUG > 0
 311                         printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n", lapb->dev);
 312 #endif
 313                         lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 314                         lapb->state = LAPB_STATE_0;
 315                         lapb_start_t1timer(lapb);
 316                         rc = LAPB_NOTCONNECTED;
 317                         goto out_put;
 318
 319                 case LAPB_STATE_2:
 320                         rc = LAPB_OK;
 321                         goto out_put;
 322         }
 323
 324         lapb_clear_queues(lapb);
 325         lapb->n2count = 0;
 326         lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 327         lapb_start_t1timer(lapb);
 328         lapb_stop_t2timer(lapb);
 329         lapb->state = LAPB_STATE_2;
 330
 331 #if LAPB_DEBUG > 1
 332         printk(KERN_DEBUG "lapb: (%p) S3 DISC(1)\n", lapb->dev);
 333 #endif
 334 #if LAPB_DEBUG > 0
 335         printk(KERN_DEBUG "lapb: (%p) S3 -> S2\n", lapb->dev);
 336 #endif
 337
 338         rc = LAPB_OK;
 339 out_put:
 340         lapb_put(lapb);
 341 out:
 342         return rc;
 343 }
 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
 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
 380 void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
 381 {
 382         if (lapb->callbacks.connect_confirmation)
 383                 lapb->callbacks.connect_confirmation(lapb->dev, reason);
 384 }
 385
 386 void lapb_connect_indication(struct lapb_cb *lapb, int reason)
 387 {
 388         if (lapb->callbacks.connect_indication)
 389                 lapb->callbacks.connect_indication(lapb->dev, reason);
 390 }
 391
 392 void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
 393 {
 394         if (lapb->callbacks.disconnect_confirmation)
 395                 lapb->callbacks.disconnect_confirmation(lapb->dev, reason);
 396 }
 397
 398 void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
 399 {
 400         if (lapb->callbacks.disconnect_indication)
 401                 lapb->callbacks.disconnect_indication(lapb->dev, reason);
 402 }
 403
 404 int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
 405 {
 406         if (lapb->callbacks.data_indication)
 407                 return lapb->callbacks.data_indication(lapb->dev, skb);
 408
 409         kfree_skb(skb);
 410         return NET_RX_CN_HIGH; /* For now; must be != NET_RX_DROP */
 411 }
 412
 413 int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
 414 {
 415         int used = 0;
 416
 417         if (lapb->callbacks.data_transmit) {
 418                 lapb->callbacks.data_transmit(lapb->dev, skb);
 419                 used = 1;
 420         }
 421
 422         return used;
 423 }
 424
 425 EXPORT_SYMBOL(lapb_register);
 426 EXPORT_SYMBOL(lapb_unregister);
 427 EXPORT_SYMBOL(lapb_getparms);
 428 EXPORT_SYMBOL(lapb_setparms);
 429 EXPORT_SYMBOL(lapb_connect_request);
 430 EXPORT_SYMBOL(lapb_disconnect_request);
 431 EXPORT_SYMBOL(lapb_data_request);
 432 EXPORT_SYMBOL(lapb_data_received);
 433
 434 static int __init lapb_init(void)
 435 {
 436         return 0;
 437 }
 438
 439 static void __exit lapb_exit(void)
 440 {
 441         WARN_ON(!list_empty(&lapb_list));
 442 }
 443
 444 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
 445 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
 446 MODULE_LICENSE("GPL");
 447
 448 module_init(lapb_init);
 449 module_exit(lapb_exit);