net/lapb/lapb_iface.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      LAPB release 002
   4  *
   5  *      This code REQUIRES 2.1.15 or higher/ NET3.038
   6  *
   7  *      History
   8  *      LAPB 001        Jonathan Naylor Started Coding
   9  *      LAPB 002        Jonathan Naylor New timer architecture.
  10  *      2000-10-29      Henner Eisen    lapb_data_indication() return status.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/module.h>
  16 #include <linux/errno.h>
  17 #include <linux/types.h>
  18 #include <linux/socket.h>
  19 #include <linux/in.h>
  20 #include <linux/kernel.h>
  21 #include <linux/jiffies.h>
  22 #include <linux/timer.h>
  23 #include <linux/string.h>
  24 #include <linux/sockios.h>
  25 #include <linux/net.h>
  26 #include <linux/inet.h>
  27 #include <linux/if_arp.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/slab.h>
  30 #include <net/sock.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/fcntl.h>
  33 #include <linux/mm.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/stat.h>
  36 #include <linux/init.h>
  37 #include <net/lapb.h>
  38
  39 static LIST_HEAD(lapb_list);
  40 static DEFINE_RWLOCK(lapb_list_lock);
  41
  42 /*
  43  *      Free an allocated lapb control block.
  44  */
  45 static void lapb_free_cb(struct lapb_cb *lapb)
  46 {
  47         kfree(lapb);
  48 }
  49
  50 static __inline__ void lapb_hold(struct lapb_cb *lapb)
  51 {
  52         refcount_inc(&lapb->refcnt);
  53 }
  54
  55 static __inline__ void lapb_put(struct lapb_cb *lapb)
  56 {
  57         if (refcount_dec_and_test(&lapb->refcnt))
  58                 lapb_free_cb(lapb);
  59 }
  60
  61 /*
  62  *      Socket removal during an interrupt is now safe.
  63  */
  64 static void __lapb_remove_cb(struct lapb_cb *lapb)
  65 {
  66         if (lapb->node.next) {
  67                 list_del(&lapb->node);
  68                 lapb_put(lapb);
  69         }
  70 }
  71 EXPORT_SYMBOL(lapb_register);
  72
  73 /*
  74  *      Add a socket to the bound sockets list.
  75  */
  76 static void __lapb_insert_cb(struct lapb_cb *lapb)
  77 {
  78         list_add(&lapb->node, &lapb_list);
  79         lapb_hold(lapb);
  80 }
  81
  82 static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
  83 {
  84         struct list_head *entry;
  85         struct lapb_cb *lapb, *use = NULL;
  86
  87         list_for_each(entry, &lapb_list) {
  88                 lapb = list_entry(entry, struct lapb_cb, node);
  89                 if (lapb->dev == dev) {
  90                         use = lapb;
  91                         break;
  92                 }
  93         }
  94
  95         if (use)
  96                 lapb_hold(use);
  97
  98         return use;
  99 }
 100
 101 static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
 102 {
 103         struct lapb_cb *rc;
 104
 105         read_lock_bh(&lapb_list_lock);
 106         rc = __lapb_devtostruct(dev);
 107         read_unlock_bh(&lapb_list_lock);
 108
 109         return rc;
 110 }
 111 /*
 112  *      Create an empty LAPB control block.
 113  */
 114 static struct lapb_cb *lapb_create_cb(void)
 115 {
 116         struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);
 117
 118
 119         if (!lapb)
 120                 goto out;
 121
 122         skb_queue_head_init(&lapb->write_queue);
 123         skb_queue_head_init(&lapb->ack_queue);
 124
 125         timer_setup(&lapb->t1timer, NULL, 0);
 126         timer_setup(&lapb->t2timer, NULL, 0);
 127
 128         lapb->t1      = LAPB_DEFAULT_T1;
 129         lapb->t2      = LAPB_DEFAULT_T2;
 130         lapb->n2      = LAPB_DEFAULT_N2;
 131         lapb->mode    = LAPB_DEFAULT_MODE;
 132         lapb->window  = LAPB_DEFAULT_WINDOW;
 133         lapb->state   = LAPB_STATE_0;
 134         refcount_set(&lapb->refcnt, 1);
 135 out:
 136         return lapb;
 137 }
 138
 139 int lapb_register(struct net_device *dev,
 140                   const struct lapb_register_struct *callbacks)
 141 {
 142         struct lapb_cb *lapb;
 143         int rc = LAPB_BADTOKEN;
 144
 145         write_lock_bh(&lapb_list_lock);
 146
 147         lapb = __lapb_devtostruct(dev);
 148         if (lapb) {
 149                 lapb_put(lapb);
 150                 goto out;
 151         }
 152
 153         lapb = lapb_create_cb();
 154         rc = LAPB_NOMEM;
 155         if (!lapb)
 156                 goto out;
 157
 158         lapb->dev       = dev;
 159         lapb->callbacks = callbacks;
 160
 161         __lapb_insert_cb(lapb);
 162
 163         lapb_start_t1timer(lapb);
 164
 165         rc = LAPB_OK;
 166 out:
 167         write_unlock_bh(&lapb_list_lock);
 168         return rc;
 169 }
 170
 171 int lapb_unregister(struct net_device *dev)
 172 {
 173         struct lapb_cb *lapb;
 174         int rc = LAPB_BADTOKEN;
 175
 176         write_lock_bh(&lapb_list_lock);
 177         lapb = __lapb_devtostruct(dev);
 178         if (!lapb)
 179                 goto out;
 180         lapb_put(lapb);
 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 EXPORT_SYMBOL(lapb_unregister);
 196
 197 int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
 198 {
 199         int rc = LAPB_BADTOKEN;
 200         struct lapb_cb *lapb = lapb_devtostruct(dev);
 201
 202         if (!lapb)
 203                 goto out;
 204
 205         parms->t1      = lapb->t1 / HZ;
 206         parms->t2      = lapb->t2 / HZ;
 207         parms->n2      = lapb->n2;
 208         parms->n2count = lapb->n2count;
 209         parms->state   = lapb->state;
 210         parms->window  = lapb->window;
 211         parms->mode    = lapb->mode;
 212
 213         if (!timer_pending(&lapb->t1timer))
 214                 parms->t1timer = 0;
 215         else
 216                 parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
 217
 218         if (!timer_pending(&lapb->t2timer))
 219                 parms->t2timer = 0;
 220         else
 221                 parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
 222
 223         lapb_put(lapb);
 224         rc = LAPB_OK;
 225 out:
 226         return rc;
 227 }
 228 EXPORT_SYMBOL(lapb_getparms);
 229
 230 int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
 231 {
 232         int rc = LAPB_BADTOKEN;
 233         struct lapb_cb *lapb = lapb_devtostruct(dev);
 234
 235         if (!lapb)
 236                 goto out;
 237
 238         rc = LAPB_INVALUE;
 239         if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
 240                 goto out_put;
 241
 242         if (lapb->state == LAPB_STATE_0) {
 243                 if (parms->mode & LAPB_EXTENDED) {
 244                         if (parms->window < 1 || parms->window > 127)
 245                                 goto out_put;
 246                 } else {
 247                         if (parms->window < 1 || parms->window > 7)
 248                                 goto out_put;
 249                 }
 250                 lapb->mode    = parms->mode;
 251                 lapb->window  = parms->window;
 252         }
 253
 254         lapb->t1    = parms->t1 * HZ;
 255         lapb->t2    = parms->t2 * HZ;
 256         lapb->n2    = parms->n2;
 257
 258         rc = LAPB_OK;
 259 out_put:
 260         lapb_put(lapb);
 261 out:
 262         return rc;
 263 }
 264 EXPORT_SYMBOL(lapb_setparms);
 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 EXPORT_SYMBOL(lapb_connect_request);
 294
 295 int lapb_disconnect_request(struct net_device *dev)
 296 {
 297         struct lapb_cb *lapb = lapb_devtostruct(dev);
 298         int rc = LAPB_BADTOKEN;
 299
 300         if (!lapb)
 301                 goto out;
 302
 303         switch (lapb->state) {
 304         case LAPB_STATE_0:
 305                 rc = LAPB_NOTCONNECTED;
 306                 goto out_put;
 307
 308         case LAPB_STATE_1:
 309                 lapb_dbg(1, "(%p) S1 TX DISC(1)\n", lapb->dev);
 310                 lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
 311                 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 312                 lapb->state = LAPB_STATE_0;
 313                 lapb_start_t1timer(lapb);
 314                 rc = LAPB_NOTCONNECTED;
 315                 goto out_put;
 316
 317         case LAPB_STATE_2:
 318                 rc = LAPB_OK;
 319                 goto out_put;
 320         }
 321
 322         lapb_clear_queues(lapb);
 323         lapb->n2count = 0;
 324         lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 325         lapb_start_t1timer(lapb);
 326         lapb_stop_t2timer(lapb);
 327         lapb->state = LAPB_STATE_2;
 328
 329         lapb_dbg(1, "(%p) S3 DISC(1)\n", lapb->dev);
 330         lapb_dbg(0, "(%p) S3 -> S2\n", lapb->dev);
 331
 332         rc = LAPB_OK;
 333 out_put:
 334         lapb_put(lapb);
 335 out:
 336         return rc;
 337 }
 338 EXPORT_SYMBOL(lapb_disconnect_request);
 339
 340 int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
 341 {
 342         struct lapb_cb *lapb = lapb_devtostruct(dev);
 343         int rc = LAPB_BADTOKEN;
 344
 345         if (!lapb)
 346                 goto out;
 347
 348         rc = LAPB_NOTCONNECTED;
 349         if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
 350                 goto out_put;
 351
 352         skb_queue_tail(&lapb->write_queue, skb);
 353         lapb_kick(lapb);
 354         rc = LAPB_OK;
 355 out_put:
 356         lapb_put(lapb);
 357 out:
 358         return rc;
 359 }
 360 EXPORT_SYMBOL(lapb_data_request);
 361
 362 int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
 363 {
 364         struct lapb_cb *lapb = lapb_devtostruct(dev);
 365         int rc = LAPB_BADTOKEN;
 366
 367         if (lapb) {
 368                 lapb_data_input(lapb, skb);
 369                 lapb_put(lapb);
 370                 rc = LAPB_OK;
 371         }
 372
 373         return rc;
 374 }
 375 EXPORT_SYMBOL(lapb_data_received);
 376
 377 void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
 378 {
 379         if (lapb->callbacks->connect_confirmation)
 380                 lapb->callbacks->connect_confirmation(lapb->dev, reason);
 381 }
 382
 383 void lapb_connect_indication(struct lapb_cb *lapb, int reason)
 384 {
 385         if (lapb->callbacks->connect_indication)
 386                 lapb->callbacks->connect_indication(lapb->dev, reason);
 387 }
 388
 389 void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
 390 {
 391         if (lapb->callbacks->disconnect_confirmation)
 392                 lapb->callbacks->disconnect_confirmation(lapb->dev, reason);
 393 }
 394
 395 void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
 396 {
 397         if (lapb->callbacks->disconnect_indication)
 398                 lapb->callbacks->disconnect_indication(lapb->dev, reason);
 399 }
 400
 401 int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
 402 {
 403         if (lapb->callbacks->data_indication)
 404                 return lapb->callbacks->data_indication(lapb->dev, skb);
 405
 406         kfree_skb(skb);
 407         return NET_RX_SUCCESS; /* For now; must be != NET_RX_DROP */
 408 }
 409
 410 int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
 411 {
 412         int used = 0;
 413
 414         if (lapb->callbacks->data_transmit) {
 415                 lapb->callbacks->data_transmit(lapb->dev, skb);
 416                 used = 1;
 417         }
 418
 419         return used;
 420 }
 421
 422 static int __init lapb_init(void)
 423 {
 424         return 0;
 425 }
 426
 427 static void __exit lapb_exit(void)
 428 {
 429         WARN_ON(!list_empty(&lapb_list));
 430 }
 431
 432 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
 433 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
 434 MODULE_LICENSE("GPL");
 435
 436 module_init(lapb_init);
 437 module_exit(lapb_exit);