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 rwlock_t lapb_list_lock = RW_LOCK_UNLOCKED;
  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 /*
  85  *      Convert the integer token used by the device driver into a pointer
  86  *      to a LAPB control structure.
  87  */
  88 static struct lapb_cb *__lapb_tokentostruct(void *token)
  89 {
  90         struct list_head *entry;
  91         struct lapb_cb *lapb, *use = NULL;
  92
  93         list_for_each(entry, &lapb_list) {
  94                 lapb = list_entry(entry, struct lapb_cb, node);
  95                 if (lapb->token == token) {
  96                         use = lapb;
  97                         break;
  98                 }
  99         }
 100
 101         if (use)
 102                 lapb_hold(use);
 103
 104         return use;
 105 }
 106
 107 static struct lapb_cb *lapb_tokentostruct(void *token)
 108 {
 109         struct lapb_cb *rc;
 110
 111         read_lock_bh(&lapb_list_lock);
 112         rc = __lapb_tokentostruct(token);
 113         read_unlock_bh(&lapb_list_lock);
 114
 115         return rc;
 116 }
 117 /*
 118  *      Create an empty LAPB control block.
 119  */
 120 static struct lapb_cb *lapb_create_cb(void)
 121 {
 122         struct lapb_cb *lapb = kmalloc(sizeof(*lapb), GFP_ATOMIC);
 123
 124
 125         if (!lapb)
 126                 goto out;
 127
 128         memset(lapb, 0x00, sizeof(*lapb));
 129
 130         skb_queue_head_init(&lapb->write_queue);
 131         skb_queue_head_init(&lapb->ack_queue);
 132
 133         init_timer(&lapb->t1timer);
 134         init_timer(&lapb->t2timer);
 135
 136         lapb->t1      = LAPB_DEFAULT_T1;
 137         lapb->t2      = LAPB_DEFAULT_T2;
 138         lapb->n2      = LAPB_DEFAULT_N2;
 139         lapb->mode    = LAPB_DEFAULT_MODE;
 140         lapb->window  = LAPB_DEFAULT_WINDOW;
 141         lapb->state   = LAPB_STATE_0;
 142         atomic_set(&lapb->refcnt, 1);
 143 out:
 144         return lapb;
 145 }
 146
 147 int lapb_register(void *token, struct lapb_register_struct *callbacks)
 148 {
 149         struct lapb_cb *lapb;
 150         int rc = LAPB_BADTOKEN;
 151
 152         write_lock_bh(&lapb_list_lock);
 153
 154         lapb = __lapb_tokentostruct(token);
 155         if (lapb) {
 156                 lapb_put(lapb);
 157                 goto out;
 158         }
 159
 160         lapb = lapb_create_cb();
 161         rc = LAPB_NOMEM;
 162         if (!lapb)
 163                 goto out;
 164
 165         lapb->token     = token;
 166         lapb->callbacks = *callbacks;
 167
 168         __lapb_insert_cb(lapb);
 169
 170         lapb_start_t1timer(lapb);
 171
 172         rc = LAPB_OK;
 173 out:
 174         write_unlock_bh(&lapb_list_lock);
 175         return rc;
 176 }
 177
 178 int lapb_unregister(void *token)
 179 {
 180         struct lapb_cb *lapb;
 181         int rc = LAPB_BADTOKEN;
 182
 183         write_unlock_bh(&lapb_list_lock);
 184         lapb = __lapb_tokentostruct(token);
 185         if (!lapb)
 186                 goto out;
 187
 188         lapb_stop_t1timer(lapb);
 189         lapb_stop_t2timer(lapb);
 190
 191         lapb_clear_queues(lapb);
 192
 193         __lapb_remove_cb(lapb);
 194
 195         lapb_put(lapb);
 196         rc = LAPB_OK;
 197 out:
 198         write_unlock_bh(&lapb_list_lock);
 199         return rc;
 200 }
 201
 202 int lapb_getparms(void *token, struct lapb_parms_struct *parms)
 203 {
 204         int rc = LAPB_BADTOKEN;
 205         struct lapb_cb *lapb = lapb_tokentostruct(token);
 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
 234 int lapb_setparms(void *token, struct lapb_parms_struct *parms)
 235 {
 236         int rc = LAPB_BADTOKEN;
 237         struct lapb_cb *lapb = lapb_tokentostruct(token);
 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                      (parms->window < 1 || parms->window > 127)) ||
 249                     (parms->window < 1 || parms->window > 7))
 250                         goto out_put;
 251
 252                 lapb->mode    = parms->mode;
 253                 lapb->window  = parms->window;
 254         }
 255
 256         lapb->t1    = parms->t1 * HZ;
 257         lapb->t2    = parms->t2 * HZ;
 258         lapb->n2    = parms->n2;
 259
 260         rc = LAPB_OK;
 261 out_put:
 262         lapb_put(lapb);
 263 out:
 264         return rc;
 265 }
 266
 267 int lapb_connect_request(void *token)
 268 {
 269         struct lapb_cb *lapb = lapb_tokentostruct(token);
 270         int rc = LAPB_BADTOKEN;
 271
 272         if (!lapb)
 273                 goto out;
 274
 275         rc = LAPB_OK;
 276         if (lapb->state == LAPB_STATE_1)
 277                 goto out_put;
 278
 279         rc = LAPB_CONNECTED;
 280         if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
 281                 goto out_put;
 282
 283         lapb_establish_data_link(lapb);
 284
 285 #if LAPB_DEBUG > 0
 286         printk(KERN_DEBUG "lapb: (%p) S0 -> S1\n", lapb->token);
 287 #endif
 288         lapb->state = LAPB_STATE_1;
 289
 290         rc = LAPB_OK;
 291 out_put:
 292         lapb_put(lapb);
 293 out:
 294         return rc;
 295 }
 296
 297 int lapb_disconnect_request(void *token)
 298 {
 299         struct lapb_cb *lapb = lapb_tokentostruct(token);
 300         int rc = LAPB_BADTOKEN;
 301
 302         if (!lapb)
 303                 goto out;
 304
 305         switch (lapb->state) {
 306                 case LAPB_STATE_0:
 307                         rc = LAPB_NOTCONNECTED;
 308                         goto out_put;
 309
 310                 case LAPB_STATE_1:
 311 #if LAPB_DEBUG > 1
 312                         printk(KERN_DEBUG "lapb: (%p) S1 TX DISC(1)\n", lapb->token);
 313 #endif
 314 #if LAPB_DEBUG > 0
 315                         printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n", lapb->token);
 316 #endif
 317                         lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 318                         lapb->state = LAPB_STATE_0;
 319                         lapb_start_t1timer(lapb);
 320                         rc = LAPB_NOTCONNECTED;
 321                         goto out_put;
 322
 323                 case LAPB_STATE_2:
 324                         rc = LAPB_OK;
 325                         goto out_put;
 326         }
 327
 328         lapb_clear_queues(lapb);
 329         lapb->n2count = 0;
 330         lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 331         lapb_start_t1timer(lapb);
 332         lapb_stop_t2timer(lapb);
 333         lapb->state = LAPB_STATE_2;
 334
 335 #if LAPB_DEBUG > 1
 336         printk(KERN_DEBUG "lapb: (%p) S3 DISC(1)\n", lapb->token);
 337 #endif
 338 #if LAPB_DEBUG > 0
 339         printk(KERN_DEBUG "lapb: (%p) S3 -> S2\n", lapb->token);
 340 #endif
 341
 342         rc = LAPB_OK;
 343 out_put:
 344         lapb_put(lapb);
 345 out:
 346         return rc;
 347 }
 348
 349 int lapb_data_request(void *token, struct sk_buff *skb)
 350 {
 351         struct lapb_cb *lapb = lapb_tokentostruct(token);
 352         int rc = LAPB_BADTOKEN;
 353
 354         if (!lapb)
 355                 goto out;
 356
 357         rc = LAPB_NOTCONNECTED;
 358         if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
 359                 goto out_put;
 360
 361         skb_queue_tail(&lapb->write_queue, skb);
 362         lapb_kick(lapb);
 363         rc = LAPB_OK;
 364 out_put:
 365         lapb_put(lapb);
 366 out:
 367         return rc;
 368 }
 369
 370 int lapb_data_received(void *token, struct sk_buff *skb)
 371 {
 372         struct lapb_cb *lapb = lapb_tokentostruct(token);
 373         int rc = LAPB_BADTOKEN;
 374
 375         if (lapb) {
 376                 lapb_data_input(lapb, skb);
 377                 lapb_put(lapb);
 378                 rc = LAPB_OK;
 379         }
 380
 381         return rc;
 382 }
 383
 384 void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
 385 {
 386         if (lapb->callbacks.connect_confirmation)
 387                 lapb->callbacks.connect_confirmation(lapb->token, reason);
 388 }
 389
 390 void lapb_connect_indication(struct lapb_cb *lapb, int reason)
 391 {
 392         if (lapb->callbacks.connect_indication)
 393                 lapb->callbacks.connect_indication(lapb->token, reason);
 394 }
 395
 396 void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
 397 {
 398         if (lapb->callbacks.disconnect_confirmation)
 399                 lapb->callbacks.disconnect_confirmation(lapb->token, reason);
 400 }
 401
 402 void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
 403 {
 404         if (lapb->callbacks.disconnect_indication)
 405                 lapb->callbacks.disconnect_indication(lapb->token, reason);
 406 }
 407
 408 int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
 409 {
 410         if (lapb->callbacks.data_indication)
 411                 return lapb->callbacks.data_indication(lapb->token, skb);
 412
 413         kfree_skb(skb);
 414         return NET_RX_CN_HIGH; /* For now; must be != NET_RX_DROP */
 415 }
 416
 417 int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
 418 {
 419         int used = 0;
 420
 421         if (lapb->callbacks.data_transmit) {
 422                 lapb->callbacks.data_transmit(lapb->token, skb);
 423                 used = 1;
 424         }
 425
 426         return used;
 427 }
 428
 429 EXPORT_SYMBOL(lapb_register);
 430 EXPORT_SYMBOL(lapb_unregister);
 431 EXPORT_SYMBOL(lapb_getparms);
 432 EXPORT_SYMBOL(lapb_setparms);
 433 EXPORT_SYMBOL(lapb_connect_request);
 434 EXPORT_SYMBOL(lapb_disconnect_request);
 435 EXPORT_SYMBOL(lapb_data_request);
 436 EXPORT_SYMBOL(lapb_data_received);
 437
 438 static int __init lapb_init(void)
 439 {
 440         return 0;
 441 }
 442
 443 static void __exit lapb_exit(void)
 444 {
 445         WARN_ON(!list_empty(&lapb_list));
 446 }
 447
 448 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
 449 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
 450 MODULE_LICENSE("GPL");
 451
 452 module_init(lapb_init);
 453 module_exit(lapb_exit);