drivers/net/wan/x25_asy.c

   1 /*
   2  *      Things to sort out:
   3  *
   4  *      o       tbusy handling
   5  *      o       allow users to set the parameters
   6  *      o       sync/async switching ?
   7  *
   8  *      Note: This does _not_ implement CCITT X.25 asynchronous framing
   9  *      recommendations. Its primarily for testing purposes. If you wanted
  10  *      to do CCITT then in theory all you need is to nick the HDLC async
  11  *      checksum routines from ppp.c
  12  *      Changes:
  13  *
  14  *      2000-10-29      Henner Eisen    lapb_data_indication() return status.
  15  */
  16
  17 #include <linux/module.h>
  18
  19 #include <asm/system.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/bitops.h>
  22 #include <linux/string.h>
  23 #include <linux/mm.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/in.h>
  26 #include <linux/tty.h>
  27 #include <linux/errno.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/etherdevice.h>
  30 #include <linux/skbuff.h>
  31 #include <linux/if_arp.h>
  32 #include <linux/lapb.h>
  33 #include <linux/init.h>
  34 #include <linux/rtnetlink.h>
  35 #include <linux/compat.h>
  36 #include <linux/slab.h>
  37 #include <net/x25device.h>
  38 #include "x25_asy.h"
  39
  40 static struct net_device **x25_asy_devs;
  41 static int x25_asy_maxdev = SL_NRUNIT;
  42
  43 module_param(x25_asy_maxdev, int, 0);
  44 MODULE_LICENSE("GPL");
  45
  46 static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
  47 static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
  48 static void x25_asy_setup(struct net_device *dev);
  49
  50 /* Find a free X.25 channel, and link in this `tty' line. */
  51 static struct x25_asy *x25_asy_alloc(void)
  52 {
  53         struct net_device *dev = NULL;
  54         struct x25_asy *sl;
  55         int i;
  56
  57         if (x25_asy_devs == NULL)
  58                 return NULL;    /* Master array missing ! */
  59
  60         for (i = 0; i < x25_asy_maxdev; i++) {
  61                 dev = x25_asy_devs[i];
  62
  63                 /* Not allocated ? */
  64                 if (dev == NULL)
  65                         break;
  66
  67                 sl = netdev_priv(dev);
  68                 /* Not in use ? */
  69                 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
  70                         return sl;
  71         }
  72
  73
  74         /* Sorry, too many, all slots in use */
  75         if (i >= x25_asy_maxdev)
  76                 return NULL;
  77
  78         /* If no channels are available, allocate one */
  79         if (!dev) {
  80                 char name[IFNAMSIZ];
  81                 sprintf(name, "x25asy%d", i);
  82
  83                 dev = alloc_netdev(sizeof(struct x25_asy),
  84                                    name, x25_asy_setup);
  85                 if (!dev)
  86                         return NULL;
  87
  88                 /* Initialize channel control data */
  89                 sl = netdev_priv(dev);
  90                 dev->base_addr    = i;
  91
  92                 /* register device so that it can be ifconfig'ed       */
  93                 if (register_netdev(dev) == 0) {
  94                         /* (Re-)Set the INUSE bit.   Very Important! */
  95                         set_bit(SLF_INUSE, &sl->flags);
  96                         x25_asy_devs[i] = dev;
  97                         return sl;
  98                 } else {
  99                         printk(KERN_WARNING "x25_asy_alloc() - register_netdev() failure.\n");
 100                         free_netdev(dev);
 101                 }
 102         }
 103         return NULL;
 104 }
 105
 106
 107 /* Free an X.25 channel. */
 108 static void x25_asy_free(struct x25_asy *sl)
 109 {
 110         /* Free all X.25 frame buffers. */
 111         kfree(sl->rbuff);
 112         sl->rbuff = NULL;
 113         kfree(sl->xbuff);
 114         sl->xbuff = NULL;
 115
 116         if (!test_and_clear_bit(SLF_INUSE, &sl->flags))
 117                 printk(KERN_ERR "%s: x25_asy_free for already free unit.\n",
 118                         sl->dev->name);
 119 }
 120
 121 static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
 122 {
 123         struct x25_asy *sl = netdev_priv(dev);
 124         unsigned char *xbuff, *rbuff;
 125         int len = 2 * newmtu;
 126
 127         xbuff = kmalloc(len + 4, GFP_ATOMIC);
 128         rbuff = kmalloc(len + 4, GFP_ATOMIC);
 129
 130         if (xbuff == NULL || rbuff == NULL) {
 131                 printk(KERN_WARNING "%s: unable to grow X.25 buffers, MTU change cancelled.\n",
 132                        dev->name);
 133                 kfree(xbuff);
 134                 kfree(rbuff);
 135                 return -ENOMEM;
 136         }
 137
 138         spin_lock_bh(&sl->lock);
 139         xbuff    = xchg(&sl->xbuff, xbuff);
 140         if (sl->xleft)  {
 141                 if (sl->xleft <= len)  {
 142                         memcpy(sl->xbuff, sl->xhead, sl->xleft);
 143                 } else  {
 144                         sl->xleft = 0;
 145                         dev->stats.tx_dropped++;
 146                 }
 147         }
 148         sl->xhead = sl->xbuff;
 149
 150         rbuff    = xchg(&sl->rbuff, rbuff);
 151         if (sl->rcount)  {
 152                 if (sl->rcount <= len) {
 153                         memcpy(sl->rbuff, rbuff, sl->rcount);
 154                 } else  {
 155                         sl->rcount = 0;
 156                         dev->stats.rx_over_errors++;
 157                         set_bit(SLF_ERROR, &sl->flags);
 158                 }
 159         }
 160
 161         dev->mtu    = newmtu;
 162         sl->buffsize = len;
 163
 164         spin_unlock_bh(&sl->lock);
 165
 166         kfree(xbuff);
 167         kfree(rbuff);
 168         return 0;
 169 }
 170
 171
 172 /* Set the "sending" flag.  This must be atomic, hence the ASM. */
 173
 174 static inline void x25_asy_lock(struct x25_asy *sl)
 175 {
 176         netif_stop_queue(sl->dev);
 177 }
 178
 179
 180 /* Clear the "sending" flag.  This must be atomic, hence the ASM. */
 181
 182 static inline void x25_asy_unlock(struct x25_asy *sl)
 183 {
 184         netif_wake_queue(sl->dev);
 185 }
 186
 187 /* Send one completely decapsulated IP datagram to the IP layer. */
 188
 189 static void x25_asy_bump(struct x25_asy *sl)
 190 {
 191         struct net_device *dev = sl->dev;
 192         struct sk_buff *skb;
 193         int count;
 194         int err;
 195
 196         count = sl->rcount;
 197         dev->stats.rx_bytes += count;
 198
 199         skb = dev_alloc_skb(count+1);
 200         if (skb == NULL) {
 201                 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n",
 202                         sl->dev->name);
 203                 dev->stats.rx_dropped++;
 204                 return;
 205         }
 206         skb_push(skb, 1);       /* LAPB internal control */
 207         memcpy(skb_put(skb, count), sl->rbuff, count);
 208         skb->protocol = x25_type_trans(skb, sl->dev);
 209         err = lapb_data_received(skb->dev, skb);
 210         if (err != LAPB_OK) {
 211                 kfree_skb(skb);
 212                 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
 213         } else {
 214                 netif_rx(skb);
 215                 dev->stats.rx_packets++;
 216         }
 217 }
 218
 219 /* Encapsulate one IP datagram and stuff into a TTY queue. */
 220 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
 221 {
 222         unsigned char *p;
 223         int actual, count, mtu = sl->dev->mtu;
 224
 225         if (len > mtu) {
 226                 /* Sigh, shouldn't occur BUT ... */
 227                 len = mtu;
 228                 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
 229                                         sl->dev->name);
 230                 sl->dev->stats.tx_dropped++;
 231                 x25_asy_unlock(sl);
 232                 return;
 233         }
 234
 235         p = icp;
 236         count = x25_asy_esc(p, (unsigned char *) sl->xbuff, len);
 237
 238         /* Order of next two lines is *very* important.
 239          * When we are sending a little amount of data,
 240          * the transfer may be completed inside driver.write()
 241          * routine, because it's running with interrupts enabled.
 242          * In this case we *never* got WRITE_WAKEUP event,
 243          * if we did not request it before write operation.
 244          *       14 Oct 1994  Dmitry Gorodchanin.
 245          */
 246         set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 247         actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
 248         sl->xleft = count - actual;
 249         sl->xhead = sl->xbuff + actual;
 250         /* VSV */
 251         clear_bit(SLF_OUTWAIT, &sl->flags);     /* reset outfill flag */
 252 }
 253
 254 /*
 255  * Called by the driver when there's room for more data.  If we have
 256  * more packets to send, we send them here.
 257  */
 258 static void x25_asy_write_wakeup(struct tty_struct *tty)
 259 {
 260         int actual;
 261         struct x25_asy *sl = tty->disc_data;
 262
 263         /* First make sure we're connected. */
 264         if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
 265                 return;
 266
 267         if (sl->xleft <= 0) {
 268                 /* Now serial buffer is almost free & we can start
 269                  * transmission of another packet */
 270                 sl->dev->stats.tx_packets++;
 271                 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 272                 x25_asy_unlock(sl);
 273                 return;
 274         }
 275
 276         actual = tty->ops->write(tty, sl->xhead, sl->xleft);
 277         sl->xleft -= actual;
 278         sl->xhead += actual;
 279 }
 280
 281 static void x25_asy_timeout(struct net_device *dev)
 282 {
 283         struct x25_asy *sl = netdev_priv(dev);
 284
 285         spin_lock(&sl->lock);
 286         if (netif_queue_stopped(dev)) {
 287                 /* May be we must check transmitter timeout here ?
 288                  *      14 Oct 1994 Dmitry Gorodchanin.
 289                  */
 290                 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
 291                        (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
 292                        "bad line quality" : "driver error");
 293                 sl->xleft = 0;
 294                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 295                 x25_asy_unlock(sl);
 296         }
 297         spin_unlock(&sl->lock);
 298 }
 299
 300 /* Encapsulate an IP datagram and kick it into a TTY queue. */
 301
 302 static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
 303                                       struct net_device *dev)
 304 {
 305         struct x25_asy *sl = netdev_priv(dev);
 306         int err;
 307
 308         if (!netif_running(sl->dev)) {
 309                 printk(KERN_ERR "%s: xmit call when iface is down\n",
 310                         dev->name);
 311                 kfree_skb(skb);
 312                 return NETDEV_TX_OK;
 313         }
 314
 315         switch (skb->data[0]) {
 316         case X25_IFACE_DATA:
 317                 break;
 318         case X25_IFACE_CONNECT: /* Connection request .. do nothing */
 319                 err = lapb_connect_request(dev);
 320                 if (err != LAPB_OK)
 321                         printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
 322                 kfree_skb(skb);
 323                 return NETDEV_TX_OK;
 324         case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
 325                 err = lapb_disconnect_request(dev);
 326                 if (err != LAPB_OK)
 327                         printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
 328         default:
 329                 kfree_skb(skb);
 330                 return NETDEV_TX_OK;
 331         }
 332         skb_pull(skb, 1);       /* Remove control byte */
 333         /*
 334          * If we are busy already- too bad.  We ought to be able
 335          * to queue things at this point, to allow for a little
 336          * frame buffer.  Oh well...
 337          * -----------------------------------------------------
 338          * I hate queues in X.25 driver. May be it's efficient,
 339          * but for me latency is more important. ;)
 340          * So, no queues !
 341          *        14 Oct 1994  Dmitry Gorodchanin.
 342          */
 343
 344         err = lapb_data_request(dev, skb);
 345         if (err != LAPB_OK) {
 346                 printk(KERN_ERR "x25_asy: lapb_data_request error - %d\n", err);
 347                 kfree_skb(skb);
 348                 return NETDEV_TX_OK;
 349         }
 350         return NETDEV_TX_OK;
 351 }
 352
 353
 354 /*
 355  *      LAPB interface boilerplate
 356  */
 357
 358 /*
 359  *      Called when I frame data arrives. We did the work above - throw it
 360  *      at the net layer.
 361  */
 362
 363 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
 364 {
 365         return netif_rx(skb);
 366 }
 367
 368 /*
 369  *      Data has emerged from the LAPB protocol machine. We don't handle
 370  *      busy cases too well. Its tricky to see how to do this nicely -
 371  *      perhaps lapb should allow us to bounce this ?
 372  */
 373
 374 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
 375 {
 376         struct x25_asy *sl = netdev_priv(dev);
 377
 378         spin_lock(&sl->lock);
 379         if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
 380                 spin_unlock(&sl->lock);
 381                 printk(KERN_ERR "x25_asy: tbusy drop\n");
 382                 kfree_skb(skb);
 383                 return;
 384         }
 385         /* We were not busy, so we are now... :-) */
 386         if (skb != NULL) {
 387                 x25_asy_lock(sl);
 388                 dev->stats.tx_bytes += skb->len;
 389                 x25_asy_encaps(sl, skb->data, skb->len);
 390                 dev_kfree_skb(skb);
 391         }
 392         spin_unlock(&sl->lock);
 393 }
 394
 395 /*
 396  *      LAPB connection establish/down information.
 397  */
 398
 399 static void x25_asy_connected(struct net_device *dev, int reason)
 400 {
 401         struct x25_asy *sl = netdev_priv(dev);
 402         struct sk_buff *skb;
 403         unsigned char *ptr;
 404
 405         skb = dev_alloc_skb(1);
 406         if (skb == NULL) {
 407                 printk(KERN_ERR "x25_asy: out of memory\n");
 408                 return;
 409         }
 410
 411         ptr  = skb_put(skb, 1);
 412         *ptr = X25_IFACE_CONNECT;
 413
 414         skb->protocol = x25_type_trans(skb, sl->dev);
 415         netif_rx(skb);
 416 }
 417
 418 static void x25_asy_disconnected(struct net_device *dev, int reason)
 419 {
 420         struct x25_asy *sl = netdev_priv(dev);
 421         struct sk_buff *skb;
 422         unsigned char *ptr;
 423
 424         skb = dev_alloc_skb(1);
 425         if (skb == NULL) {
 426                 printk(KERN_ERR "x25_asy: out of memory\n");
 427                 return;
 428         }
 429
 430         ptr  = skb_put(skb, 1);
 431         *ptr = X25_IFACE_DISCONNECT;
 432
 433         skb->protocol = x25_type_trans(skb, sl->dev);
 434         netif_rx(skb);
 435 }
 436
 437 static struct lapb_register_struct x25_asy_callbacks = {
 438         .connect_confirmation = x25_asy_connected,
 439         .connect_indication = x25_asy_connected,
 440         .disconnect_confirmation = x25_asy_disconnected,
 441         .disconnect_indication = x25_asy_disconnected,
 442         .data_indication = x25_asy_data_indication,
 443         .data_transmit = x25_asy_data_transmit,
 444
 445 };
 446
 447
 448 /* Open the low-level part of the X.25 channel. Easy! */
 449 static int x25_asy_open(struct net_device *dev)
 450 {
 451         struct x25_asy *sl = netdev_priv(dev);
 452         unsigned long len;
 453         int err;
 454
 455         if (sl->tty == NULL)
 456                 return -ENODEV;
 457
 458         /*
 459          * Allocate the X.25 frame buffers:
 460          *
 461          * rbuff        Receive buffer.
 462          * xbuff        Transmit buffer.
 463          */
 464
 465         len = dev->mtu * 2;
 466
 467         sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
 468         if (sl->rbuff == NULL)
 469                 goto norbuff;
 470         sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
 471         if (sl->xbuff == NULL)
 472                 goto noxbuff;
 473
 474         sl->buffsize = len;
 475         sl->rcount   = 0;
 476         sl->xleft    = 0;
 477         sl->flags   &= (1 << SLF_INUSE);      /* Clear ESCAPE & ERROR flags */
 478
 479         netif_start_queue(dev);
 480
 481         /*
 482          *      Now attach LAPB
 483          */
 484         err = lapb_register(dev, &x25_asy_callbacks);
 485         if (err == LAPB_OK)
 486                 return 0;
 487
 488         /* Cleanup */
 489         kfree(sl->xbuff);
 490 noxbuff:
 491         kfree(sl->rbuff);
 492 norbuff:
 493         return -ENOMEM;
 494 }
 495
 496
 497 /* Close the low-level part of the X.25 channel. Easy! */
 498 static int x25_asy_close(struct net_device *dev)
 499 {
 500         struct x25_asy *sl = netdev_priv(dev);
 501
 502         spin_lock(&sl->lock);
 503         if (sl->tty)
 504                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 505
 506         netif_stop_queue(dev);
 507         sl->rcount = 0;
 508         sl->xleft  = 0;
 509         spin_unlock(&sl->lock);
 510         return 0;
 511 }
 512
 513 /*
 514  * Handle the 'receiver data ready' interrupt.
 515  * This function is called by the 'tty_io' module in the kernel when
 516  * a block of X.25 data has been received, which can now be decapsulated
 517  * and sent on to some IP layer for further processing.
 518  */
 519
 520 static void x25_asy_receive_buf(struct tty_struct *tty,
 521                                 const unsigned char *cp, char *fp, int count)
 522 {
 523         struct x25_asy *sl = tty->disc_data;
 524
 525         if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
 526                 return;
 527
 528
 529         /* Read the characters out of the buffer */
 530         while (count--) {
 531                 if (fp && *fp++) {
 532                         if (!test_and_set_bit(SLF_ERROR, &sl->flags))
 533                                 sl->dev->stats.rx_errors++;
 534                         cp++;
 535                         continue;
 536                 }
 537                 x25_asy_unesc(sl, *cp++);
 538         }
 539 }
 540
 541 /*
 542  * Open the high-level part of the X.25 channel.
 543  * This function is called by the TTY module when the
 544  * X.25 line discipline is called for.  Because we are
 545  * sure the tty line exists, we only have to link it to
 546  * a free X.25 channel...
 547  */
 548
 549 static int x25_asy_open_tty(struct tty_struct *tty)
 550 {
 551         struct x25_asy *sl = tty->disc_data;
 552         int err;
 553
 554         if (tty->ops->write == NULL)
 555                 return -EOPNOTSUPP;
 556
 557         /* First make sure we're not already connected. */
 558         if (sl && sl->magic == X25_ASY_MAGIC)
 559                 return -EEXIST;
 560
 561         /* OK.  Find a free X.25 channel to use. */
 562         sl = x25_asy_alloc();
 563         if (sl == NULL)
 564                 return -ENFILE;
 565
 566         sl->tty = tty;
 567         tty->disc_data = sl;
 568         tty->receive_room = 65536;
 569         tty_driver_flush_buffer(tty);
 570         tty_ldisc_flush(tty);
 571
 572         /* Restore default settings */
 573         sl->dev->type = ARPHRD_X25;
 574
 575         /* Perform the low-level X.25 async init */
 576         err = x25_asy_open(sl->dev);
 577         if (err)
 578                 return err;
 579         /* Done.  We have linked the TTY line to a channel. */
 580         return 0;
 581 }
 582
 583
 584 /*
 585  * Close down an X.25 channel.
 586  * This means flushing out any pending queues, and then restoring the
 587  * TTY line discipline to what it was before it got hooked to X.25
 588  * (which usually is TTY again).
 589  */
 590 static void x25_asy_close_tty(struct tty_struct *tty)
 591 {
 592         struct x25_asy *sl = tty->disc_data;
 593         int err;
 594
 595         /* First make sure we're connected. */
 596         if (!sl || sl->magic != X25_ASY_MAGIC)
 597                 return;
 598
 599         rtnl_lock();
 600         if (sl->dev->flags & IFF_UP)
 601                 dev_close(sl->dev);
 602         rtnl_unlock();
 603
 604         err = lapb_unregister(sl->dev);
 605         if (err != LAPB_OK)
 606                 printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",
 607                         err);
 608
 609         tty->disc_data = NULL;
 610         sl->tty = NULL;
 611         x25_asy_free(sl);
 612 }
 613
 614  /************************************************************************
 615   *                     STANDARD X.25 ENCAPSULATION                      *
 616   ************************************************************************/
 617
 618 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
 619 {
 620         unsigned char *ptr = d;
 621         unsigned char c;
 622
 623         /*
 624          * Send an initial END character to flush out any
 625          * data that may have accumulated in the receiver
 626          * due to line noise.
 627          */
 628
 629         *ptr++ = X25_END;       /* Send 10111110 bit seq */
 630
 631         /*
 632          * For each byte in the packet, send the appropriate
 633          * character sequence, according to the X.25 protocol.
 634          */
 635
 636         while (len-- > 0) {
 637                 switch (c = *s++) {
 638                 case X25_END:
 639                         *ptr++ = X25_ESC;
 640                         *ptr++ = X25_ESCAPE(X25_END);
 641                         break;
 642                 case X25_ESC:
 643                         *ptr++ = X25_ESC;
 644                         *ptr++ = X25_ESCAPE(X25_ESC);
 645                         break;
 646                 default:
 647                         *ptr++ = c;
 648                         break;
 649                 }
 650         }
 651         *ptr++ = X25_END;
 652         return ptr - d;
 653 }
 654
 655 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
 656 {
 657
 658         switch (s) {
 659         case X25_END:
 660                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
 661                     sl->rcount > 2)
 662                         x25_asy_bump(sl);
 663                 clear_bit(SLF_ESCAPE, &sl->flags);
 664                 sl->rcount = 0;
 665                 return;
 666         case X25_ESC:
 667                 set_bit(SLF_ESCAPE, &sl->flags);
 668                 return;
 669         case X25_ESCAPE(X25_ESC):
 670         case X25_ESCAPE(X25_END):
 671                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
 672                         s = X25_UNESCAPE(s);
 673                 break;
 674         }
 675         if (!test_bit(SLF_ERROR, &sl->flags)) {
 676                 if (sl->rcount < sl->buffsize) {
 677                         sl->rbuff[sl->rcount++] = s;
 678                         return;
 679                 }
 680                 sl->dev->stats.rx_over_errors++;
 681                 set_bit(SLF_ERROR, &sl->flags);
 682         }
 683 }
 684
 685
 686 /* Perform I/O control on an active X.25 channel. */
 687 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
 688                          unsigned int cmd,  unsigned long arg)
 689 {
 690         struct x25_asy *sl = tty->disc_data;
 691
 692         /* First make sure we're connected. */
 693         if (!sl || sl->magic != X25_ASY_MAGIC)
 694                 return -EINVAL;
 695
 696         switch (cmd) {
 697         case SIOCGIFNAME:
 698                 if (copy_to_user((void __user *)arg, sl->dev->name,
 699                                         strlen(sl->dev->name) + 1))
 700                         return -EFAULT;
 701                 return 0;
 702         case SIOCSIFHWADDR:
 703                 return -EINVAL;
 704         default:
 705                 return tty_mode_ioctl(tty, file, cmd, arg);
 706         }
 707 }
 708
 709 #ifdef CONFIG_COMPAT
 710 static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
 711                          unsigned int cmd,  unsigned long arg)
 712 {
 713         switch (cmd) {
 714         case SIOCGIFNAME:
 715         case SIOCSIFHWADDR:
 716                 return x25_asy_ioctl(tty, file, cmd,
 717                                      (unsigned long)compat_ptr(arg));
 718         }
 719
 720         return -ENOIOCTLCMD;
 721 }
 722 #endif
 723
 724 static int x25_asy_open_dev(struct net_device *dev)
 725 {
 726         struct x25_asy *sl = netdev_priv(dev);
 727         if (sl->tty == NULL)
 728                 return -ENODEV;
 729         return 0;
 730 }
 731
 732 static const struct net_device_ops x25_asy_netdev_ops = {
 733         .ndo_open       = x25_asy_open_dev,
 734         .ndo_stop       = x25_asy_close,
 735         .ndo_start_xmit = x25_asy_xmit,
 736         .ndo_tx_timeout = x25_asy_timeout,
 737         .ndo_change_mtu = x25_asy_change_mtu,
 738 };
 739
 740 /* Initialise the X.25 driver.  Called by the device init code */
 741 static void x25_asy_setup(struct net_device *dev)
 742 {
 743         struct x25_asy *sl = netdev_priv(dev);
 744
 745         sl->magic  = X25_ASY_MAGIC;
 746         sl->dev    = dev;
 747         spin_lock_init(&sl->lock);
 748         set_bit(SLF_INUSE, &sl->flags);
 749
 750         /*
 751          *      Finish setting up the DEVICE info.
 752          */
 753
 754         dev->mtu                = SL_MTU;
 755         dev->netdev_ops         = &x25_asy_netdev_ops;
 756         dev->watchdog_timeo     = HZ*20;
 757         dev->hard_header_len    = 0;
 758         dev->addr_len           = 0;
 759         dev->type               = ARPHRD_X25;
 760         dev->tx_queue_len       = 10;
 761
 762         /* New-style flags. */
 763         dev->flags              = IFF_NOARP;
 764 }
 765
 766 static struct tty_ldisc_ops x25_ldisc = {
 767         .owner          = THIS_MODULE,
 768         .magic          = TTY_LDISC_MAGIC,
 769         .name           = "X.25",
 770         .open           = x25_asy_open_tty,
 771         .close          = x25_asy_close_tty,
 772         .ioctl          = x25_asy_ioctl,
 773 #ifdef CONFIG_COMPAT
 774         .compat_ioctl   = x25_asy_compat_ioctl,
 775 #endif
 776         .receive_buf    = x25_asy_receive_buf,
 777         .write_wakeup   = x25_asy_write_wakeup,
 778 };
 779
 780 static int __init init_x25_asy(void)
 781 {
 782         if (x25_asy_maxdev < 4)
 783                 x25_asy_maxdev = 4; /* Sanity */
 784
 785         printk(KERN_INFO "X.25 async: version 0.00 ALPHA "
 786                         "(dynamic channels, max=%d).\n", x25_asy_maxdev);
 787
 788         x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
 789                                 GFP_KERNEL);
 790         if (!x25_asy_devs) {
 791                 printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] "
 792                                 "array! Uaargh! (-> No X.25 available)\n");
 793                 return -ENOMEM;
 794         }
 795
 796         return tty_register_ldisc(N_X25, &x25_ldisc);
 797 }
 798
 799
 800 static void __exit exit_x25_asy(void)
 801 {
 802         struct net_device *dev;
 803         int i;
 804
 805         for (i = 0; i < x25_asy_maxdev; i++) {
 806                 dev = x25_asy_devs[i];
 807                 if (dev) {
 808                         struct x25_asy *sl = netdev_priv(dev);
 809
 810                         spin_lock_bh(&sl->lock);
 811                         if (sl->tty)
 812                                 tty_hangup(sl->tty);
 813
 814                         spin_unlock_bh(&sl->lock);
 815                         /*
 816                          * VSV = if dev->start==0, then device
 817                          * unregistered while close proc.
 818                          */
 819                         unregister_netdev(dev);
 820                         free_netdev(dev);
 821                 }
 822         }
 823
 824         kfree(x25_asy_devs);
 825         tty_unregister_ldisc(N_X25);
 826 }
 827
 828 module_init(init_x25_asy);
 829 module_exit(exit_x25_asy);