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/x25.h>
  33 #include <linux/lapb.h>
  34 #include <linux/init.h>
  35 #include <linux/rtnetlink.h>
  36 #include <linux/compat.h>
  37 #include "x25_asy.h"
  38
  39 #include <net/x25device.h>
  40
  41 static struct net_device **x25_asy_devs;
  42 static int x25_asy_maxdev = SL_NRUNIT;
  43
  44 module_param(x25_asy_maxdev, int, 0);
  45 MODULE_LICENSE("GPL");
  46
  47 static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
  48 static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
  49 static void x25_asy_setup(struct net_device *dev);
  50
  51 /* Find a free X.25 channel, and link in this `tty' line. */
  52 static struct x25_asy *x25_asy_alloc(void)
  53 {
  54         struct net_device *dev = NULL;
  55         struct x25_asy *sl;
  56         int i;
  57
  58         if (x25_asy_devs == NULL)
  59                 return NULL;    /* Master array missing ! */
  60
  61         for (i = 0; i < x25_asy_maxdev; i++) {
  62                 dev = x25_asy_devs[i];
  63
  64                 /* Not allocated ? */
  65                 if (dev == NULL)
  66                         break;
  67
  68                 sl = netdev_priv(dev);
  69                 /* Not in use ? */
  70                 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
  71                         return sl;
  72         }
  73
  74
  75         /* Sorry, too many, all slots in use */
  76         if (i >= x25_asy_maxdev)
  77                 return NULL;
  78
  79         /* If no channels are available, allocate one */
  80         if (!dev) {
  81                 char name[IFNAMSIZ];
  82                 sprintf(name, "x25asy%d", i);
  83
  84                 dev = alloc_netdev(sizeof(struct x25_asy),
  85                                    name, x25_asy_setup);
  86                 if (!dev)
  87                         return NULL;
  88
  89                 /* Initialize channel control data */
  90                 sl = netdev_priv(dev);
  91                 dev->base_addr    = i;
  92
  93                 /* register device so that it can be ifconfig'ed       */
  94                 if (register_netdev(dev) == 0) {
  95                         /* (Re-)Set the INUSE bit.   Very Important! */
  96                         set_bit(SLF_INUSE, &sl->flags);
  97                         x25_asy_devs[i] = dev;
  98                         return sl;
  99                 } else {
 100                         printk(KERN_WARNING "x25_asy_alloc() - register_netdev() failure.\n");
 101                         free_netdev(dev);
 102                 }
 103         }
 104         return NULL;
 105 }
 106
 107
 108 /* Free an X.25 channel. */
 109 static void x25_asy_free(struct x25_asy *sl)
 110 {
 111         /* Free all X.25 frame buffers. */
 112         kfree(sl->rbuff);
 113         sl->rbuff = NULL;
 114         kfree(sl->xbuff);
 115         sl->xbuff = NULL;
 116
 117         if (!test_and_clear_bit(SLF_INUSE, &sl->flags))
 118                 printk(KERN_ERR "%s: x25_asy_free for already free unit.\n",
 119                         sl->dev->name);
 120 }
 121
 122 static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
 123 {
 124         struct x25_asy *sl = netdev_priv(dev);
 125         unsigned char *xbuff, *rbuff;
 126         int len = 2 * newmtu;
 127
 128         xbuff = kmalloc(len + 4, GFP_ATOMIC);
 129         rbuff = kmalloc(len + 4, GFP_ATOMIC);
 130
 131         if (xbuff == NULL || rbuff == NULL) {
 132                 printk(KERN_WARNING "%s: unable to grow X.25 buffers, MTU change cancelled.\n",
 133                        dev->name);
 134                 kfree(xbuff);
 135                 kfree(rbuff);
 136                 return -ENOMEM;
 137         }
 138
 139         spin_lock_bh(&sl->lock);
 140         xbuff    = xchg(&sl->xbuff, xbuff);
 141         if (sl->xleft)  {
 142                 if (sl->xleft <= len)  {
 143                         memcpy(sl->xbuff, sl->xhead, sl->xleft);
 144                 } else  {
 145                         sl->xleft = 0;
 146                         dev->stats.tx_dropped++;
 147                 }
 148         }
 149         sl->xhead = sl->xbuff;
 150
 151         rbuff    = xchg(&sl->rbuff, rbuff);
 152         if (sl->rcount)  {
 153                 if (sl->rcount <= len) {
 154                         memcpy(sl->rbuff, rbuff, sl->rcount);
 155                 } else  {
 156                         sl->rcount = 0;
 157                         dev->stats.rx_over_errors++;
 158                         set_bit(SLF_ERROR, &sl->flags);
 159                 }
 160         }
 161
 162         dev->mtu    = newmtu;
 163         sl->buffsize = len;
 164
 165         spin_unlock_bh(&sl->lock);
 166
 167         kfree(xbuff);
 168         kfree(rbuff);
 169         return 0;
 170 }
 171
 172
 173 /* Set the "sending" flag.  This must be atomic, hence the ASM. */
 174
 175 static inline void x25_asy_lock(struct x25_asy *sl)
 176 {
 177         netif_stop_queue(sl->dev);
 178 }
 179
 180
 181 /* Clear the "sending" flag.  This must be atomic, hence the ASM. */
 182
 183 static inline void x25_asy_unlock(struct x25_asy *sl)
 184 {
 185         netif_wake_queue(sl->dev);
 186 }
 187
 188 /* Send one completely decapsulated IP datagram to the IP layer. */
 189
 190 static void x25_asy_bump(struct x25_asy *sl)
 191 {
 192         struct net_device *dev = sl->dev;
 193         struct sk_buff *skb;
 194         int count;
 195         int err;
 196
 197         count = sl->rcount;
 198         dev->stats.rx_bytes += count;
 199
 200         skb = dev_alloc_skb(count+1);
 201         if (skb == NULL) {
 202                 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n",
 203                         sl->dev->name);
 204                 dev->stats.rx_dropped++;
 205                 return;
 206         }
 207         skb_push(skb, 1);       /* LAPB internal control */
 208         memcpy(skb_put(skb, count), sl->rbuff, count);
 209         skb->protocol = x25_type_trans(skb, sl->dev);
 210         err = lapb_data_received(skb->dev, skb);
 211         if (err != LAPB_OK) {
 212                 kfree_skb(skb);
 213                 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
 214         } else {
 215                 netif_rx(skb);
 216                 dev->stats.rx_packets++;
 217         }
 218 }
 219
 220 /* Encapsulate one IP datagram and stuff into a TTY queue. */
 221 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
 222 {
 223         unsigned char *p;
 224         int actual, count, mtu = sl->dev->mtu;
 225
 226         if (len > mtu) {
 227                 /* Sigh, shouldn't occur BUT ... */
 228                 len = mtu;
 229                 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
 230                                         sl->dev->name);
 231                 sl->dev->stats.tx_dropped++;
 232                 x25_asy_unlock(sl);
 233                 return;
 234         }
 235
 236         p = icp;
 237         count = x25_asy_esc(p, (unsigned char *) sl->xbuff, len);
 238
 239         /* Order of next two lines is *very* important.
 240          * When we are sending a little amount of data,
 241          * the transfer may be completed inside driver.write()
 242          * routine, because it's running with interrupts enabled.
 243          * In this case we *never* got WRITE_WAKEUP event,
 244          * if we did not request it before write operation.
 245          *       14 Oct 1994  Dmitry Gorodchanin.
 246          */
 247         set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 248         actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
 249         sl->xleft = count - actual;
 250         sl->xhead = sl->xbuff + actual;
 251         /* VSV */
 252         clear_bit(SLF_OUTWAIT, &sl->flags);     /* reset outfill flag */
 253 }
 254
 255 /*
 256  * Called by the driver when there's room for more data.  If we have
 257  * more packets to send, we send them here.
 258  */
 259 static void x25_asy_write_wakeup(struct tty_struct *tty)
 260 {
 261         int actual;
 262         struct x25_asy *sl = tty->disc_data;
 263
 264         /* First make sure we're connected. */
 265         if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
 266                 return;
 267
 268         if (sl->xleft <= 0) {
 269                 /* Now serial buffer is almost free & we can start
 270                  * transmission of another packet */
 271                 sl->dev->stats.tx_packets++;
 272                 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 273                 x25_asy_unlock(sl);
 274                 return;
 275         }
 276
 277         actual = tty->ops->write(tty, sl->xhead, sl->xleft);
 278         sl->xleft -= actual;
 279         sl->xhead += actual;
 280 }
 281
 282 static void x25_asy_timeout(struct net_device *dev)
 283 {
 284         struct x25_asy *sl = netdev_priv(dev);
 285
 286         spin_lock(&sl->lock);
 287         if (netif_queue_stopped(dev)) {
 288                 /* May be we must check transmitter timeout here ?
 289                  *      14 Oct 1994 Dmitry Gorodchanin.
 290                  */
 291                 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
 292                        (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
 293                        "bad line quality" : "driver error");
 294                 sl->xleft = 0;
 295                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 296                 x25_asy_unlock(sl);
 297         }
 298         spin_unlock(&sl->lock);
 299 }
 300
 301 /* Encapsulate an IP datagram and kick it into a TTY queue. */
 302
 303 static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
 304                                       struct net_device *dev)
 305 {
 306         struct x25_asy *sl = netdev_priv(dev);
 307         int err;
 308
 309         if (!netif_running(sl->dev)) {
 310                 printk(KERN_ERR "%s: xmit call when iface is down\n",
 311                         dev->name);
 312                 kfree_skb(skb);
 313                 return NETDEV_TX_OK;
 314         }
 315
 316         switch (skb->data[0]) {
 317         case 0x00:
 318                 break;
 319         case 0x01: /* Connection request .. do nothing */
 320                 err = lapb_connect_request(dev);
 321                 if (err != LAPB_OK)
 322                         printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
 323                 kfree_skb(skb);
 324                 return NETDEV_TX_OK;
 325         case 0x02: /* Disconnect request .. do nothing - hang up ?? */
 326                 err = lapb_disconnect_request(dev);
 327                 if (err != LAPB_OK)
 328                         printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
 329         default:
 330                 kfree_skb(skb);
 331                 return NETDEV_TX_OK;
 332         }
 333         skb_pull(skb, 1);       /* Remove control byte */
 334         /*
 335          * If we are busy already- too bad.  We ought to be able
 336          * to queue things at this point, to allow for a little
 337          * frame buffer.  Oh well...
 338          * -----------------------------------------------------
 339          * I hate queues in X.25 driver. May be it's efficient,
 340          * but for me latency is more important. ;)
 341          * So, no queues !
 342          *        14 Oct 1994  Dmitry Gorodchanin.
 343          */
 344
 345         err = lapb_data_request(dev, skb);
 346         if (err != LAPB_OK) {
 347                 printk(KERN_ERR "x25_asy: lapb_data_request error - %d\n", err);
 348                 kfree_skb(skb);
 349                 return NETDEV_TX_OK;
 350         }
 351         return NETDEV_TX_OK;
 352 }
 353
 354
 355 /*
 356  *      LAPB interface boilerplate
 357  */
 358
 359 /*
 360  *      Called when I frame data arrives. We did the work above - throw it
 361  *      at the net layer.
 362  */
 363
 364 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
 365 {
 366         return netif_rx(skb);
 367 }
 368
 369 /*
 370  *      Data has emerged from the LAPB protocol machine. We don't handle
 371  *      busy cases too well. Its tricky to see how to do this nicely -
 372  *      perhaps lapb should allow us to bounce this ?
 373  */
 374
 375 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
 376 {
 377         struct x25_asy *sl = netdev_priv(dev);
 378
 379         spin_lock(&sl->lock);
 380         if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
 381                 spin_unlock(&sl->lock);
 382                 printk(KERN_ERR "x25_asy: tbusy drop\n");
 383                 kfree_skb(skb);
 384                 return;
 385         }
 386         /* We were not busy, so we are now... :-) */
 387         if (skb != NULL) {
 388                 x25_asy_lock(sl);
 389                 dev->stats.tx_bytes += skb->len;
 390                 x25_asy_encaps(sl, skb->data, skb->len);
 391                 dev_kfree_skb(skb);
 392         }
 393         spin_unlock(&sl->lock);
 394 }
 395
 396 /*
 397  *      LAPB connection establish/down information.
 398  */
 399
 400 static void x25_asy_connected(struct net_device *dev, int reason)
 401 {
 402         struct x25_asy *sl = netdev_priv(dev);
 403         struct sk_buff *skb;
 404         unsigned char *ptr;
 405
 406         skb = dev_alloc_skb(1);
 407         if (skb == NULL) {
 408                 printk(KERN_ERR "x25_asy: out of memory\n");
 409                 return;
 410         }
 411
 412         ptr  = skb_put(skb, 1);
 413         *ptr = 0x01;
 414
 415         skb->protocol = x25_type_trans(skb, sl->dev);
 416         netif_rx(skb);
 417 }
 418
 419 static void x25_asy_disconnected(struct net_device *dev, int reason)
 420 {
 421         struct x25_asy *sl = netdev_priv(dev);
 422         struct sk_buff *skb;
 423         unsigned char *ptr;
 424
 425         skb = dev_alloc_skb(1);
 426         if (skb == NULL) {
 427                 printk(KERN_ERR "x25_asy: out of memory\n");
 428                 return;
 429         }
 430
 431         ptr  = skb_put(skb, 1);
 432         *ptr = 0x02;
 433
 434         skb->protocol = x25_type_trans(skb, sl->dev);
 435         netif_rx(skb);
 436 }
 437
 438 static struct lapb_register_struct x25_asy_callbacks = {
 439         .connect_confirmation = x25_asy_connected,
 440         .connect_indication = x25_asy_connected,
 441         .disconnect_confirmation = x25_asy_disconnected,
 442         .disconnect_indication = x25_asy_disconnected,
 443         .data_indication = x25_asy_data_indication,
 444         .data_transmit = x25_asy_data_transmit,
 445
 446 };
 447
 448
 449 /* Open the low-level part of the X.25 channel. Easy! */
 450 static int x25_asy_open(struct net_device *dev)
 451 {
 452         struct x25_asy *sl = netdev_priv(dev);
 453         unsigned long len;
 454         int err;
 455
 456         if (sl->tty == NULL)
 457                 return -ENODEV;
 458
 459         /*
 460          * Allocate the X.25 frame buffers:
 461          *
 462          * rbuff        Receive buffer.
 463          * xbuff        Transmit buffer.
 464          */
 465
 466         len = dev->mtu * 2;
 467
 468         sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
 469         if (sl->rbuff == NULL)
 470                 goto norbuff;
 471         sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
 472         if (sl->xbuff == NULL)
 473                 goto noxbuff;
 474
 475         sl->buffsize = len;
 476         sl->rcount   = 0;
 477         sl->xleft    = 0;
 478         sl->flags   &= (1 << SLF_INUSE);      /* Clear ESCAPE & ERROR flags */
 479
 480         netif_start_queue(dev);
 481
 482         /*
 483          *      Now attach LAPB
 484          */
 485         err = lapb_register(dev, &x25_asy_callbacks);
 486         if (err == LAPB_OK)
 487                 return 0;
 488
 489         /* Cleanup */
 490         kfree(sl->xbuff);
 491 noxbuff:
 492         kfree(sl->rbuff);
 493 norbuff:
 494         return -ENOMEM;
 495 }
 496
 497
 498 /* Close the low-level part of the X.25 channel. Easy! */
 499 static int x25_asy_close(struct net_device *dev)
 500 {
 501         struct x25_asy *sl = netdev_priv(dev);
 502         int err;
 503
 504         spin_lock(&sl->lock);
 505         if (sl->tty)
 506                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 507
 508         netif_stop_queue(dev);
 509         sl->rcount = 0;
 510         sl->xleft  = 0;
 511         err = lapb_unregister(dev);
 512         if (err != LAPB_OK)
 513                 printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",
 514                         err);
 515         spin_unlock(&sl->lock);
 516         return 0;
 517 }
 518
 519 /*
 520  * Handle the 'receiver data ready' interrupt.
 521  * This function is called by the 'tty_io' module in the kernel when
 522  * a block of X.25 data has been received, which can now be decapsulated
 523  * and sent on to some IP layer for further processing.
 524  */
 525
 526 static void x25_asy_receive_buf(struct tty_struct *tty,
 527                                 const unsigned char *cp, char *fp, int count)
 528 {
 529         struct x25_asy *sl = tty->disc_data;
 530
 531         if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
 532                 return;
 533
 534
 535         /* Read the characters out of the buffer */
 536         while (count--) {
 537                 if (fp && *fp++) {
 538                         if (!test_and_set_bit(SLF_ERROR, &sl->flags))
 539                                 sl->dev->stats.rx_errors++;
 540                         cp++;
 541                         continue;
 542                 }
 543                 x25_asy_unesc(sl, *cp++);
 544         }
 545 }
 546
 547 /*
 548  * Open the high-level part of the X.25 channel.
 549  * This function is called by the TTY module when the
 550  * X.25 line discipline is called for.  Because we are
 551  * sure the tty line exists, we only have to link it to
 552  * a free X.25 channel...
 553  */
 554
 555 static int x25_asy_open_tty(struct tty_struct *tty)
 556 {
 557         struct x25_asy *sl = tty->disc_data;
 558         int err;
 559
 560         if (tty->ops->write == NULL)
 561                 return -EOPNOTSUPP;
 562
 563         /* First make sure we're not already connected. */
 564         if (sl && sl->magic == X25_ASY_MAGIC)
 565                 return -EEXIST;
 566
 567         /* OK.  Find a free X.25 channel to use. */
 568         sl = x25_asy_alloc();
 569         if (sl == NULL)
 570                 return -ENFILE;
 571
 572         sl->tty = tty;
 573         tty->disc_data = sl;
 574         tty->receive_room = 65536;
 575         tty_driver_flush_buffer(tty);
 576         tty_ldisc_flush(tty);
 577
 578         /* Restore default settings */
 579         sl->dev->type = ARPHRD_X25;
 580
 581         /* Perform the low-level X.25 async init */
 582         err = x25_asy_open(sl->dev);
 583         if (err)
 584                 return err;
 585         /* Done.  We have linked the TTY line to a channel. */
 586         return sl->dev->base_addr;
 587 }
 588
 589
 590 /*
 591  * Close down an X.25 channel.
 592  * This means flushing out any pending queues, and then restoring the
 593  * TTY line discipline to what it was before it got hooked to X.25
 594  * (which usually is TTY again).
 595  */
 596 static void x25_asy_close_tty(struct tty_struct *tty)
 597 {
 598         struct x25_asy *sl = tty->disc_data;
 599
 600         /* First make sure we're connected. */
 601         if (!sl || sl->magic != X25_ASY_MAGIC)
 602                 return;
 603
 604         rtnl_lock();
 605         if (sl->dev->flags & IFF_UP)
 606                 dev_close(sl->dev);
 607         rtnl_unlock();
 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);