drivers/net/slip.c

   1 /*
   2  * slip.c       This module implements the SLIP protocol for kernel-based
   3  *              devices like TTY.  It interfaces between a raw TTY, and the
   4  *              kernel's INET protocol layers.
   5  *
   6  * Version:     @(#)slip.c      0.8.3   12/24/94
   7  *
   8  * Authors:     Laurence Culhane, <loz@holmes.demon.co.uk>
   9  *              Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
  10  *
  11  * Fixes:
  12  *              Alan Cox        :       Sanity checks and avoid tx overruns.
  13  *                                      Has a new sl->mtu field.
  14  *              Alan Cox        :       Found cause of overrun. ifconfig sl0 mtu upwards.
  15  *                                      Driver now spots this and grows/shrinks its buffers(hack!).
  16  *                                      Memory leak if you run out of memory setting up a slip driver fixed.
  17  *              Matt Dillon     :       Printable slip (borrowed from NET2E)
  18  *      Pauline Middelink       :       Slip driver fixes.
  19  *              Alan Cox        :       Honours the old SL_COMPRESSED flag
  20  *              Alan Cox        :       KISS AX.25 and AXUI IP support
  21  *              Michael Riepe   :       Automatic CSLIP recognition added
  22  *              Charles Hedrick :       CSLIP header length problem fix.
  23  *              Alan Cox        :       Corrected non-IP cases of the above.
  24  *              Alan Cox        :       Now uses hardware type as per FvK.
  25  *              Alan Cox        :       Default to 192.168.0.0 (RFC 1597)
  26  *              A.N.Kuznetsov   :       dev_tint() recursion fix.
  27  *      Dmitry Gorodchanin      :       SLIP memory leaks
  28  *      Dmitry Gorodchanin      :       Code cleanup. Reduce tty driver
  29  *                                      buffering from 4096 to 256 bytes.
  30  *                                      Improving SLIP response time.
  31  *                                      CONFIG_SLIP_MODE_SLIP6.
  32  *                                      ifconfig sl? up & down now works correctly.
  33  *                                      Modularization.
  34  *              Alan Cox        :       Oops - fix AX.25 buffer lengths
  35  *      Dmitry Gorodchanin      :       Even more cleanups. Preserve CSLIP
  36  *                                      statistics. Include CSLIP code only
  37  *                                      if it really needed.
  38  *              Alan Cox        :       Free slhc buffers in the right place.
  39  *              Alan Cox        :       Allow for digipeated IP over AX.25
  40  *              Matti Aarnio    :       Dynamic SLIP devices, with ideas taken
  41  *                                      from Jim Freeman's <jfree@caldera.com>
  42  *                                      dynamic PPP devices.  We do NOT kfree()
  43  *                                      device entries, just reg./unreg. them
  44  *                                      as they are needed.  We kfree() them
  45  *                                      at module cleanup.
  46  *                                      With MODULE-loading ``insmod'', user can
  47  *                                      issue parameter:   slip_maxdev=1024
  48  *                                      (Or how much he/she wants.. Default is 256)
  49  * *    Stanislav Voronyi       :       Slip line checking, with ideas taken
  50  *                                      from multislip BSDI driver which was written
  51  *                                      by Igor Chechik, RELCOM Corp. Only algorithms
  52  *                                      have been ported to Linux SLIP driver.
  53  *      Vitaly E. Lavrov        :       Sane behaviour on tty hangup.
  54  *      Alexey Kuznetsov        :       Cleanup interfaces to tty&netdevice modules.
  55  */
  56
  57 #define SL_CHECK_TRANSMIT
  58 #include <linux/config.h>
  59 #include <linux/module.h>
  60 #include <linux/moduleparam.h>
  61
  62 #include <asm/system.h>
  63 #include <asm/uaccess.h>
  64 #include <linux/bitops.h>
  65 #include <linux/string.h>
  66 #include <linux/mm.h>
  67 #include <linux/interrupt.h>
  68 #include <linux/in.h>
  69 #include <linux/tty.h>
  70 #include <linux/errno.h>
  71 #include <linux/netdevice.h>
  72 #include <linux/etherdevice.h>
  73 #include <linux/skbuff.h>
  74 #include <linux/rtnetlink.h>
  75 #include <linux/if_arp.h>
  76 #include <linux/if_slip.h>
  77 #include <linux/init.h>
  78 #include "slip.h"
  79 #ifdef CONFIG_INET
  80 #include <linux/ip.h>
  81 #include <linux/tcp.h>
  82 #include <net/slhc_vj.h>
  83 #endif
  84
  85 #define SLIP_VERSION    "0.8.4-NET3.019-NEWTTY"
  86
  87 static struct net_device **slip_devs;
  88
  89 static int slip_maxdev = SL_NRUNIT;
  90 module_param(slip_maxdev, int, 0);
  91 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
  92
  93 static int slip_esc(unsigned char *p, unsigned char *d, int len);
  94 static void slip_unesc(struct slip *sl, unsigned char c);
  95 #ifdef CONFIG_SLIP_MODE_SLIP6
  96 static int slip_esc6(unsigned char *p, unsigned char *d, int len);
  97 static void slip_unesc6(struct slip *sl, unsigned char c);
  98 #endif
  99 #ifdef CONFIG_SLIP_SMART
 100 static void sl_keepalive(unsigned long sls);
 101 static void sl_outfill(unsigned long sls);
 102 static int sl_ioctl(struct net_device *dev,struct ifreq *rq,int cmd);
 103 #endif
 104
 105 /********************************
 106 *  Buffer administration routines:
 107 *       sl_alloc_bufs()
 108 *       sl_free_bufs()
 109 *       sl_realloc_bufs()
 110 *
 111 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because
 112 *       sl_realloc_bufs provides strong atomicity and reallocation
 113 *       on actively running device.
 114 *********************************/
 115
 116 /*
 117    Allocate channel buffers.
 118  */
 119
 120 static int
 121 sl_alloc_bufs(struct slip *sl, int mtu)
 122 {
 123         int err = -ENOBUFS;
 124         unsigned long len;
 125         char * rbuff = NULL;
 126         char * xbuff = NULL;
 127 #ifdef SL_INCLUDE_CSLIP
 128         char * cbuff = NULL;
 129         struct slcompress *slcomp = NULL;
 130 #endif
 131
 132         /*
 133          * Allocate the SLIP frame buffers:
 134          *
 135          * rbuff        Receive buffer.
 136          * xbuff        Transmit buffer.
 137          * cbuff        Temporary compression buffer.
 138          */
 139         len = mtu * 2;
 140
 141         /*
 142          * allow for arrival of larger UDP packets, even if we say not to
 143          * also fixes a bug in which SunOS sends 512-byte packets even with
 144          * an MSS of 128
 145          */
 146         if (len < 576 * 2)
 147                 len = 576 * 2;
 148         rbuff = kmalloc(len + 4, GFP_KERNEL);
 149         if (rbuff == NULL)
 150                 goto err_exit;
 151         xbuff = kmalloc(len + 4, GFP_KERNEL);
 152         if (xbuff == NULL)
 153                 goto err_exit;
 154 #ifdef SL_INCLUDE_CSLIP
 155         cbuff = kmalloc(len + 4, GFP_KERNEL);
 156         if (cbuff == NULL)
 157                 goto err_exit;
 158         slcomp = slhc_init(16, 16);
 159         if (slcomp == NULL)
 160                 goto err_exit;
 161 #endif
 162         spin_lock_bh(&sl->lock);
 163         if (sl->tty == NULL) {
 164                 spin_unlock_bh(&sl->lock);
 165                 err = -ENODEV;
 166                 goto err_exit;
 167         }
 168         sl->mtu      = mtu;
 169         sl->buffsize = len;
 170         sl->rcount   = 0;
 171         sl->xleft    = 0;
 172         rbuff = xchg(&sl->rbuff, rbuff);
 173         xbuff = xchg(&sl->xbuff, xbuff);
 174 #ifdef SL_INCLUDE_CSLIP
 175         cbuff = xchg(&sl->cbuff, cbuff);
 176         slcomp = xchg(&sl->slcomp, slcomp);
 177 #ifdef CONFIG_SLIP_MODE_SLIP6
 178         sl->xdata    = 0;
 179         sl->xbits    = 0;
 180 #endif
 181 #endif
 182         spin_unlock_bh(&sl->lock);
 183         err = 0;
 184
 185         /* Cleanup */
 186 err_exit:
 187 #ifdef SL_INCLUDE_CSLIP
 188         kfree(cbuff);
 189         if (slcomp)
 190                 slhc_free(slcomp);
 191 #endif
 192         kfree(xbuff);
 193         kfree(rbuff);
 194         return err;
 195 }
 196
 197 /* Free a SLIP channel buffers. */
 198 static void
 199 sl_free_bufs(struct slip *sl)
 200 {
 201         void * tmp;
 202
 203         /* Free all SLIP frame buffers. */
 204         tmp = xchg(&sl->rbuff, NULL);
 205         kfree(tmp);
 206         tmp = xchg(&sl->xbuff, NULL);
 207         kfree(tmp);
 208 #ifdef SL_INCLUDE_CSLIP
 209         tmp = xchg(&sl->cbuff, NULL);
 210         kfree(tmp);
 211         if ((tmp = xchg(&sl->slcomp, NULL)) != NULL)
 212                 slhc_free(tmp);
 213 #endif
 214 }
 215
 216 /*
 217    Reallocate slip channel buffers.
 218  */
 219
 220 static int sl_realloc_bufs(struct slip *sl, int mtu)
 221 {
 222         int err = 0;
 223         struct net_device *dev = sl->dev;
 224         unsigned char *xbuff, *rbuff;
 225 #ifdef SL_INCLUDE_CSLIP
 226         unsigned char *cbuff;
 227 #endif
 228         int len = mtu * 2;
 229
 230 /*
 231  * allow for arrival of larger UDP packets, even if we say not to
 232  * also fixes a bug in which SunOS sends 512-byte packets even with
 233  * an MSS of 128
 234  */
 235         if (len < 576 * 2)
 236                 len = 576 * 2;
 237
 238         xbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
 239         rbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
 240 #ifdef SL_INCLUDE_CSLIP
 241         cbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
 242 #endif
 243
 244
 245 #ifdef SL_INCLUDE_CSLIP
 246         if (xbuff == NULL || rbuff == NULL || cbuff == NULL)  {
 247 #else
 248         if (xbuff == NULL || rbuff == NULL)  {
 249 #endif
 250                 if (mtu >= sl->mtu) {
 251                         printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n",
 252                                dev->name);
 253                         err = -ENOBUFS;
 254                 }
 255                 goto done;
 256         }
 257
 258         spin_lock_bh(&sl->lock);
 259
 260         err = -ENODEV;
 261         if (sl->tty == NULL)
 262                 goto done_on_bh;
 263
 264         xbuff    = xchg(&sl->xbuff, xbuff);
 265         rbuff    = xchg(&sl->rbuff, rbuff);
 266 #ifdef SL_INCLUDE_CSLIP
 267         cbuff    = xchg(&sl->cbuff, cbuff);
 268 #endif
 269         if (sl->xleft)  {
 270                 if (sl->xleft <= len)  {
 271                         memcpy(sl->xbuff, sl->xhead, sl->xleft);
 272                 } else  {
 273                         sl->xleft = 0;
 274                         sl->tx_dropped++;
 275                 }
 276         }
 277         sl->xhead = sl->xbuff;
 278
 279         if (sl->rcount)  {
 280                 if (sl->rcount <= len) {
 281                         memcpy(sl->rbuff, rbuff, sl->rcount);
 282                 } else  {
 283                         sl->rcount = 0;
 284                         sl->rx_over_errors++;
 285                         set_bit(SLF_ERROR, &sl->flags);
 286                 }
 287         }
 288         sl->mtu      = mtu;
 289         dev->mtu      = mtu;
 290         sl->buffsize = len;
 291         err = 0;
 292
 293 done_on_bh:
 294         spin_unlock_bh(&sl->lock);
 295
 296 done:
 297         kfree(xbuff);
 298         kfree(rbuff);
 299 #ifdef SL_INCLUDE_CSLIP
 300         kfree(cbuff);
 301 #endif
 302         return err;
 303 }
 304
 305
 306 /* Set the "sending" flag.  This must be atomic hence the set_bit. */
 307 static inline void
 308 sl_lock(struct slip *sl)
 309 {
 310         netif_stop_queue(sl->dev);
 311 }
 312
 313
 314 /* Clear the "sending" flag.  This must be atomic, hence the ASM. */
 315 static inline void
 316 sl_unlock(struct slip *sl)
 317 {
 318         netif_wake_queue(sl->dev);
 319 }
 320
 321 /* Send one completely decapsulated IP datagram to the IP layer. */
 322 static void
 323 sl_bump(struct slip *sl)
 324 {
 325         struct sk_buff *skb;
 326         int count;
 327
 328         count = sl->rcount;
 329 #ifdef SL_INCLUDE_CSLIP
 330         if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
 331                 unsigned char c;
 332                 if ((c = sl->rbuff[0]) & SL_TYPE_COMPRESSED_TCP) {
 333                         /* ignore compressed packets when CSLIP is off */
 334                         if (!(sl->mode & SL_MODE_CSLIP)) {
 335                                 printk(KERN_WARNING "%s: compressed packet ignored\n", sl->dev->name);
 336                                 return;
 337                         }
 338                         /* make sure we've reserved enough space for uncompress to use */
 339                         if (count + 80 > sl->buffsize) {
 340                                 sl->rx_over_errors++;
 341                                 return;
 342                         }
 343                         count = slhc_uncompress(sl->slcomp, sl->rbuff, count);
 344                         if (count <= 0) {
 345                                 return;
 346                         }
 347                 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {
 348                         if (!(sl->mode & SL_MODE_CSLIP)) {
 349                                 /* turn on header compression */
 350                                 sl->mode |= SL_MODE_CSLIP;
 351                                 sl->mode &= ~SL_MODE_ADAPTIVE;
 352                                 printk(KERN_INFO "%s: header compression turned on\n", sl->dev->name);
 353                         }
 354                         sl->rbuff[0] &= 0x4f;
 355                         if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0) {
 356                                 return;
 357                         }
 358                 }
 359         }
 360 #endif  /* SL_INCLUDE_CSLIP */
 361
 362         sl->rx_bytes+=count;
 363
 364         skb = dev_alloc_skb(count);
 365         if (skb == NULL)  {
 366                 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", sl->dev->name);
 367                 sl->rx_dropped++;
 368                 return;
 369         }
 370         skb->dev = sl->dev;
 371         memcpy(skb_put(skb,count), sl->rbuff, count);
 372         skb->mac.raw=skb->data;
 373         skb->protocol=htons(ETH_P_IP);
 374         netif_rx(skb);
 375         sl->dev->last_rx = jiffies;
 376         sl->rx_packets++;
 377 }
 378
 379 /* Encapsulate one IP datagram and stuff into a TTY queue. */
 380 static void
 381 sl_encaps(struct slip *sl, unsigned char *icp, int len)
 382 {
 383         unsigned char *p;
 384         int actual, count;
 385
 386         if (len > sl->mtu) {            /* Sigh, shouldn't occur BUT ... */
 387                 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name);
 388                 sl->tx_dropped++;
 389                 sl_unlock(sl);
 390                 return;
 391         }
 392
 393         p = icp;
 394 #ifdef SL_INCLUDE_CSLIP
 395         if (sl->mode & SL_MODE_CSLIP)  {
 396                 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);
 397         }
 398 #endif
 399 #ifdef CONFIG_SLIP_MODE_SLIP6
 400         if(sl->mode & SL_MODE_SLIP6)
 401                 count = slip_esc6(p, (unsigned char *) sl->xbuff, len);
 402         else
 403 #endif
 404                 count = slip_esc(p, (unsigned char *) sl->xbuff, len);
 405
 406         /* Order of next two lines is *very* important.
 407          * When we are sending a little amount of data,
 408          * the transfer may be completed inside driver.write()
 409          * routine, because it's running with interrupts enabled.
 410          * In this case we *never* got WRITE_WAKEUP event,
 411          * if we did not request it before write operation.
 412          *       14 Oct 1994  Dmitry Gorodchanin.
 413          */
 414         sl->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
 415         actual = sl->tty->driver->write(sl->tty, sl->xbuff, count);
 416 #ifdef SL_CHECK_TRANSMIT
 417         sl->dev->trans_start = jiffies;
 418 #endif
 419         sl->xleft = count - actual;
 420         sl->xhead = sl->xbuff + actual;
 421 #ifdef CONFIG_SLIP_SMART
 422         /* VSV */
 423         clear_bit(SLF_OUTWAIT, &sl->flags);     /* reset outfill flag */
 424 #endif
 425 }
 426
 427 /*
 428  * Called by the driver when there's room for more data.  If we have
 429  * more packets to send, we send them here.
 430  */
 431 static void slip_write_wakeup(struct tty_struct *tty)
 432 {
 433         int actual;
 434         struct slip *sl = (struct slip *) tty->disc_data;
 435
 436         /* First make sure we're connected. */
 437         if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) {
 438                 return;
 439         }
 440         if (sl->xleft <= 0)  {
 441                 /* Now serial buffer is almost free & we can start
 442                  * transmission of another packet */
 443                 sl->tx_packets++;
 444                 tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
 445                 sl_unlock(sl);
 446                 return;
 447         }
 448
 449         actual = tty->driver->write(tty, sl->xhead, sl->xleft);
 450         sl->xleft -= actual;
 451         sl->xhead += actual;
 452 }
 453
 454 static void sl_tx_timeout(struct net_device *dev)
 455 {
 456         struct slip *sl = netdev_priv(dev);
 457
 458         spin_lock(&sl->lock);
 459
 460         if (netif_queue_stopped(dev)) {
 461                 if (!netif_running(dev))
 462                         goto out;
 463
 464                 /* May be we must check transmitter timeout here ?
 465                  *      14 Oct 1994 Dmitry Gorodchanin.
 466                  */
 467 #ifdef SL_CHECK_TRANSMIT
 468                 if (time_before(jiffies, dev->trans_start + 20 * HZ))  {
 469                         /* 20 sec timeout not reached */
 470                         goto out;
 471                 }
 472                 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
 473                        (sl->tty->driver->chars_in_buffer(sl->tty) || sl->xleft) ?
 474                        "bad line quality" : "driver error");
 475                 sl->xleft = 0;
 476                 sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
 477                 sl_unlock(sl);
 478 #endif
 479         }
 480
 481 out:
 482         spin_unlock(&sl->lock);
 483 }
 484
 485
 486 /* Encapsulate an IP datagram and kick it into a TTY queue. */
 487 static int
 488 sl_xmit(struct sk_buff *skb, struct net_device *dev)
 489 {
 490         struct slip *sl = netdev_priv(dev);
 491
 492         spin_lock(&sl->lock);
 493         if (!netif_running(dev))  {
 494                 spin_unlock(&sl->lock);
 495                 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
 496                 dev_kfree_skb(skb);
 497                 return 0;
 498         }
 499         if (sl->tty == NULL) {
 500                 spin_unlock(&sl->lock);
 501                 dev_kfree_skb(skb);
 502                 return 0;
 503         }
 504
 505         sl_lock(sl);
 506         sl->tx_bytes+=skb->len;
 507         sl_encaps(sl, skb->data, skb->len);
 508         spin_unlock(&sl->lock);
 509
 510         dev_kfree_skb(skb);
 511         return 0;
 512 }
 513
 514
 515 /******************************************
 516  *   Routines looking at netdevice side.
 517  ******************************************/
 518
 519 /* Netdevice UP -> DOWN routine */
 520
 521 static int
 522 sl_close(struct net_device *dev)
 523 {
 524         struct slip *sl = netdev_priv(dev);
 525
 526         spin_lock_bh(&sl->lock);
 527         if (sl->tty) {
 528                 /* TTY discipline is running. */
 529                 sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
 530         }
 531         netif_stop_queue(dev);
 532         sl->rcount   = 0;
 533         sl->xleft    = 0;
 534         spin_unlock_bh(&sl->lock);
 535
 536         return 0;
 537 }
 538
 539 /* Netdevice DOWN -> UP routine */
 540
 541 static int sl_open(struct net_device *dev)
 542 {
 543         struct slip *sl = netdev_priv(dev);
 544
 545         if (sl->tty==NULL)
 546                 return -ENODEV;
 547
 548         sl->flags &= (1 << SLF_INUSE);
 549         netif_start_queue(dev);
 550         return 0;
 551 }
 552
 553 /* Netdevice change MTU request */
 554
 555 static int sl_change_mtu(struct net_device *dev, int new_mtu)
 556 {
 557         struct slip *sl = netdev_priv(dev);
 558
 559         if (new_mtu < 68 || new_mtu > 65534)
 560                 return -EINVAL;
 561
 562         if (new_mtu != dev->mtu)
 563                 return sl_realloc_bufs(sl, new_mtu);
 564         return 0;
 565 }
 566
 567 /* Netdevice get statistics request */
 568
 569 static struct net_device_stats *
 570 sl_get_stats(struct net_device *dev)
 571 {
 572         static struct net_device_stats stats;
 573         struct slip *sl = netdev_priv(dev);
 574 #ifdef SL_INCLUDE_CSLIP
 575         struct slcompress *comp;
 576 #endif
 577
 578         memset(&stats, 0, sizeof(struct net_device_stats));
 579
 580         stats.rx_packets     = sl->rx_packets;
 581         stats.tx_packets     = sl->tx_packets;
 582         stats.rx_bytes       = sl->rx_bytes;
 583         stats.tx_bytes       = sl->tx_bytes;
 584         stats.rx_dropped     = sl->rx_dropped;
 585         stats.tx_dropped     = sl->tx_dropped;
 586         stats.tx_errors      = sl->tx_errors;
 587         stats.rx_errors      = sl->rx_errors;
 588         stats.rx_over_errors = sl->rx_over_errors;
 589 #ifdef SL_INCLUDE_CSLIP
 590         stats.rx_fifo_errors = sl->rx_compressed;
 591         stats.tx_fifo_errors = sl->tx_compressed;
 592         stats.collisions     = sl->tx_misses;
 593         comp = sl->slcomp;
 594         if (comp) {
 595                 stats.rx_fifo_errors += comp->sls_i_compressed;
 596                 stats.rx_dropped     += comp->sls_i_tossed;
 597                 stats.tx_fifo_errors += comp->sls_o_compressed;
 598                 stats.collisions     += comp->sls_o_misses;
 599         }
 600 #endif /* CONFIG_INET */
 601         return (&stats);
 602 }
 603
 604 /* Netdevice register callback */
 605
 606 static int sl_init(struct net_device *dev)
 607 {
 608         struct slip *sl = netdev_priv(dev);
 609
 610         /*
 611          *      Finish setting up the DEVICE info.
 612          */
 613
 614         dev->mtu                = sl->mtu;
 615         dev->type               = ARPHRD_SLIP + sl->mode;
 616 #ifdef SL_CHECK_TRANSMIT
 617         dev->tx_timeout         = sl_tx_timeout;
 618         dev->watchdog_timeo     = 20*HZ;
 619 #endif
 620         return 0;
 621 }
 622
 623
 624 static void sl_uninit(struct net_device *dev)
 625 {
 626         struct slip *sl = netdev_priv(dev);
 627
 628         sl_free_bufs(sl);
 629 }
 630
 631 static void sl_setup(struct net_device *dev)
 632 {
 633         dev->init               = sl_init;
 634         dev->uninit             = sl_uninit;
 635         dev->open               = sl_open;
 636         dev->destructor         = free_netdev;
 637         dev->stop               = sl_close;
 638         dev->get_stats          = sl_get_stats;
 639         dev->change_mtu         = sl_change_mtu;
 640         dev->hard_start_xmit    = sl_xmit;
 641 #ifdef CONFIG_SLIP_SMART
 642         dev->do_ioctl           = sl_ioctl;
 643 #endif
 644         dev->hard_header_len    = 0;
 645         dev->addr_len           = 0;
 646         dev->tx_queue_len       = 10;
 647
 648         SET_MODULE_OWNER(dev);
 649
 650         /* New-style flags. */
 651         dev->flags              = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
 652 }
 653
 654 /******************************************
 655   Routines looking at TTY side.
 656  ******************************************/
 657
 658
 659 static int slip_receive_room(struct tty_struct *tty)
 660 {
 661         return 65536;  /* We can handle an infinite amount of data. :-) */
 662 }
 663
 664 /*
 665  * Handle the 'receiver data ready' interrupt.
 666  * This function is called by the 'tty_io' module in the kernel when
 667  * a block of SLIP data has been received, which can now be decapsulated
 668  * and sent on to some IP layer for further processing. This will not
 669  * be re-entered while running but other ldisc functions may be called
 670  * in parallel
 671  */
 672
 673 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, char *fp, int count)
 674 {
 675         struct slip *sl = (struct slip *) tty->disc_data;
 676
 677         if (!sl || sl->magic != SLIP_MAGIC ||
 678             !netif_running(sl->dev))
 679                 return;
 680
 681         /* Read the characters out of the buffer */
 682         while (count--) {
 683                 if (fp && *fp++) {
 684                         if (!test_and_set_bit(SLF_ERROR, &sl->flags))  {
 685                                 sl->rx_errors++;
 686                         }
 687                         cp++;
 688                         continue;
 689                 }
 690 #ifdef CONFIG_SLIP_MODE_SLIP6
 691                 if (sl->mode & SL_MODE_SLIP6)
 692                         slip_unesc6(sl, *cp++);
 693                 else
 694 #endif
 695                         slip_unesc(sl, *cp++);
 696         }
 697 }
 698
 699 /************************************
 700  *  slip_open helper routines.
 701  ************************************/
 702
 703 /* Collect hanged up channels */
 704
 705 static void sl_sync(void)
 706 {
 707         int i;
 708         struct net_device *dev;
 709         struct slip       *sl;
 710
 711         for (i = 0; i < slip_maxdev; i++) {
 712                 if ((dev = slip_devs[i]) == NULL)
 713                         break;
 714
 715                 sl = netdev_priv(dev);
 716                 if (sl->tty || sl->leased)
 717                         continue;
 718                 if (dev->flags&IFF_UP)
 719                         dev_close(dev);
 720         }
 721 }
 722
 723
 724 /* Find a free SLIP channel, and link in this `tty' line. */
 725 static struct slip *
 726 sl_alloc(dev_t line)
 727 {
 728         int i;
 729         int sel = -1;
 730         int score = -1;
 731         struct net_device *dev = NULL;
 732         struct slip       *sl;
 733
 734         if (slip_devs == NULL)
 735                 return NULL;    /* Master array missing ! */
 736
 737         for (i = 0; i < slip_maxdev; i++) {
 738                 dev = slip_devs[i];
 739                 if (dev == NULL)
 740                         break;
 741
 742                 sl = netdev_priv(dev);
 743                 if (sl->leased) {
 744                         if (sl->line != line)
 745                                 continue;
 746                         if (sl->tty)
 747                                 return NULL;
 748
 749                         /* Clear ESCAPE & ERROR flags */
 750                         sl->flags &= (1 << SLF_INUSE);
 751                         return sl;
 752                 }
 753
 754                 if (sl->tty)
 755                         continue;
 756
 757                 if (current->pid == sl->pid) {
 758                         if (sl->line == line && score < 3) {
 759                                 sel = i;
 760                                 score = 3;
 761                                 continue;
 762                         }
 763                         if (score < 2) {
 764                                 sel = i;
 765                                 score = 2;
 766                         }
 767                         continue;
 768                 }
 769                 if (sl->line == line && score < 1) {
 770                         sel = i;
 771                         score = 1;
 772                         continue;
 773                 }
 774                 if (score < 0) {
 775                         sel = i;
 776                         score = 0;
 777                 }
 778         }
 779
 780         if (sel >= 0) {
 781                 i = sel;
 782                 dev = slip_devs[i];
 783                 if (score > 1) {
 784                         sl = netdev_priv(dev);
 785                         sl->flags &= (1 << SLF_INUSE);
 786                         return sl;
 787                 }
 788         }
 789
 790         /* Sorry, too many, all slots in use */
 791         if (i >= slip_maxdev)
 792                 return NULL;
 793
 794         if (dev) {
 795                 sl = netdev_priv(dev);
 796                 if (test_bit(SLF_INUSE, &sl->flags)) {
 797                         unregister_netdevice(dev);
 798                         dev = NULL;
 799                         slip_devs[i] = NULL;
 800                 }
 801         }
 802
 803         if (!dev) {
 804                 char name[IFNAMSIZ];
 805                 sprintf(name, "sl%d", i);
 806
 807                 dev = alloc_netdev(sizeof(*sl), name, sl_setup);
 808                 if (!dev)
 809                         return NULL;
 810                 dev->base_addr  = i;
 811         }
 812
 813         sl = netdev_priv(dev);
 814
 815         /* Initialize channel control data */
 816         sl->magic       = SLIP_MAGIC;
 817         sl->dev         = dev;
 818         spin_lock_init(&sl->lock);
 819         sl->mode        = SL_MODE_DEFAULT;
 820 #ifdef CONFIG_SLIP_SMART
 821         init_timer(&sl->keepalive_timer);       /* initialize timer_list struct */
 822         sl->keepalive_timer.data=(unsigned long)sl;
 823         sl->keepalive_timer.function=sl_keepalive;
 824         init_timer(&sl->outfill_timer);
 825         sl->outfill_timer.data=(unsigned long)sl;
 826         sl->outfill_timer.function=sl_outfill;
 827 #endif
 828         slip_devs[i] = dev;
 829
 830         return sl;
 831 }
 832
 833 /*
 834  * Open the high-level part of the SLIP channel.
 835  * This function is called by the TTY module when the
 836  * SLIP line discipline is called for.  Because we are
 837  * sure the tty line exists, we only have to link it to
 838  * a free SLIP channel...
 839  *
 840  * Called in process context serialized from other ldisc calls.
 841  */
 842
 843 static int slip_open(struct tty_struct *tty)
 844 {
 845         struct slip *sl;
 846         int err;
 847
 848         if(!capable(CAP_NET_ADMIN))
 849                 return -EPERM;
 850
 851         /* RTnetlink lock is misused here to serialize concurrent
 852            opens of slip channels. There are better ways, but it is
 853            the simplest one.
 854          */
 855         rtnl_lock();
 856
 857         /* Collect hanged up channels. */
 858         sl_sync();
 859
 860         sl = (struct slip *) tty->disc_data;
 861
 862         err = -EEXIST;
 863         /* First make sure we're not already connected. */
 864         if (sl && sl->magic == SLIP_MAGIC)
 865                 goto err_exit;
 866
 867         /* OK.  Find a free SLIP channel to use. */
 868         err = -ENFILE;
 869         if ((sl = sl_alloc(tty_devnum(tty))) == NULL)
 870                 goto err_exit;
 871
 872         sl->tty = tty;
 873         tty->disc_data = sl;
 874         sl->line = tty_devnum(tty);
 875         sl->pid = current->pid;
 876
 877         /* FIXME: already done before we were called - seems this can go */
 878         if (tty->driver->flush_buffer)
 879                 tty->driver->flush_buffer(tty);
 880
 881         if (!test_bit(SLF_INUSE, &sl->flags)) {
 882                 /* Perform the low-level SLIP initialization. */
 883                 if ((err = sl_alloc_bufs(sl, SL_MTU)) != 0)
 884                         goto err_free_chan;
 885
 886                 set_bit(SLF_INUSE, &sl->flags);
 887
 888                 if ((err = register_netdevice(sl->dev)))
 889                         goto err_free_bufs;
 890         }
 891
 892 #ifdef CONFIG_SLIP_SMART
 893         if (sl->keepalive) {
 894                 sl->keepalive_timer.expires=jiffies+sl->keepalive*HZ;
 895                 add_timer (&sl->keepalive_timer);
 896         }
 897         if (sl->outfill) {
 898                 sl->outfill_timer.expires=jiffies+sl->outfill*HZ;
 899                 add_timer (&sl->outfill_timer);
 900         }
 901 #endif
 902
 903         /* Done.  We have linked the TTY line to a channel. */
 904         rtnl_unlock();
 905         return sl->dev->base_addr;
 906
 907 err_free_bufs:
 908         sl_free_bufs(sl);
 909
 910 err_free_chan:
 911         sl->tty = NULL;
 912         tty->disc_data = NULL;
 913         clear_bit(SLF_INUSE, &sl->flags);
 914
 915 err_exit:
 916         rtnl_unlock();
 917
 918         /* Count references from TTY module */
 919         return err;
 920 }
 921
 922 /*
 923
 924   FIXME: 1,2 are fixed 3 was never true anyway.
 925
 926    Let me to blame a bit.
 927    1. TTY module calls this funstion on soft interrupt.
 928    2. TTY module calls this function WITH MASKED INTERRUPTS!
 929    3. TTY module does not notify us about line discipline
 930       shutdown,
 931
 932    Seems, now it is clean. The solution is to consider netdevice and
 933    line discipline sides as two independent threads.
 934
 935    By-product (not desired): sl? does not feel hangups and remains open.
 936    It is supposed, that user level program (dip, diald, slattach...)
 937    will catch SIGHUP and make the rest of work.
 938
 939    I see no way to make more with current tty code. --ANK
 940  */
 941
 942 /*
 943  * Close down a SLIP channel.
 944  * This means flushing out any pending queues, and then returning. This
 945  * call is serialized against other ldisc functions.
 946  */
 947 static void
 948 slip_close(struct tty_struct *tty)
 949 {
 950         struct slip *sl = (struct slip *) tty->disc_data;
 951
 952         /* First make sure we're connected. */
 953         if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
 954                 return;
 955
 956         tty->disc_data = NULL;
 957         sl->tty = NULL;
 958         if (!sl->leased)
 959                 sl->line = 0;
 960
 961         /* VSV = very important to remove timers */
 962 #ifdef CONFIG_SLIP_SMART
 963         del_timer_sync(&sl->keepalive_timer);
 964         del_timer_sync(&sl->outfill_timer);
 965 #endif
 966
 967         /* Count references from TTY module */
 968 }
 969
 970  /************************************************************************
 971   *                     STANDARD SLIP ENCAPSULATION                      *
 972   ************************************************************************/
 973
 974 int
 975 slip_esc(unsigned char *s, unsigned char *d, int len)
 976 {
 977         unsigned char *ptr = d;
 978         unsigned char c;
 979
 980         /*
 981          * Send an initial END character to flush out any
 982          * data that may have accumulated in the receiver
 983          * due to line noise.
 984          */
 985
 986         *ptr++ = END;
 987
 988         /*
 989          * For each byte in the packet, send the appropriate
 990          * character sequence, according to the SLIP protocol.
 991          */
 992
 993         while (len-- > 0) {
 994                 switch(c = *s++) {
 995                  case END:
 996                         *ptr++ = ESC;
 997                         *ptr++ = ESC_END;
 998                         break;
 999                  case ESC:
1000                         *ptr++ = ESC;
1001                         *ptr++ = ESC_ESC;
1002                         break;
1003                  default:
1004                         *ptr++ = c;
1005                         break;
1006                 }
1007         }
1008         *ptr++ = END;
1009         return (ptr - d);
1010 }
1011
1012 static void slip_unesc(struct slip *sl, unsigned char s)
1013 {
1014
1015         switch(s) {
1016          case END:
1017 #ifdef CONFIG_SLIP_SMART
1018                 /* drop keeptest bit = VSV */
1019                 if (test_bit(SLF_KEEPTEST, &sl->flags))
1020                         clear_bit(SLF_KEEPTEST, &sl->flags);
1021 #endif
1022
1023                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2))  {
1024                         sl_bump(sl);
1025                 }
1026                 clear_bit(SLF_ESCAPE, &sl->flags);
1027                 sl->rcount = 0;
1028                 return;
1029
1030          case ESC:
1031                 set_bit(SLF_ESCAPE, &sl->flags);
1032                 return;
1033          case ESC_ESC:
1034                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))  {
1035                         s = ESC;
1036                 }
1037                 break;
1038          case ESC_END:
1039                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))  {
1040                         s = END;
1041                 }
1042                 break;
1043         }
1044         if (!test_bit(SLF_ERROR, &sl->flags))  {
1045                 if (sl->rcount < sl->buffsize)  {
1046                         sl->rbuff[sl->rcount++] = s;
1047                         return;
1048                 }
1049                 sl->rx_over_errors++;
1050                 set_bit(SLF_ERROR, &sl->flags);
1051         }
1052 }
1053
1054
1055 #ifdef CONFIG_SLIP_MODE_SLIP6
1056 /************************************************************************
1057  *                       6 BIT SLIP ENCAPSULATION                       *
1058  ************************************************************************/
1059
1060 int
1061 slip_esc6(unsigned char *s, unsigned char *d, int len)
1062 {
1063         unsigned char *ptr = d;
1064         unsigned char c;
1065         int i;
1066         unsigned short v = 0;
1067         short bits = 0;
1068
1069         /*
1070          * Send an initial END character to flush out any
1071          * data that may have accumulated in the receiver
1072          * due to line noise.
1073          */
1074
1075         *ptr++ = 0x70;
1076
1077         /*
1078          * Encode the packet into printable ascii characters
1079          */
1080
1081         for (i = 0; i < len; ++i) {
1082                 v = (v << 8) | s[i];
1083                 bits += 8;
1084                 while (bits >= 6) {
1085                         bits -= 6;
1086                         c = 0x30 + ((v >> bits) & 0x3F);
1087                         *ptr++ = c;
1088                 }
1089         }
1090         if (bits) {
1091                 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1092                 *ptr++ = c;
1093         }
1094         *ptr++ = 0x70;
1095         return ptr - d;
1096 }
1097
1098 void
1099 slip_unesc6(struct slip *sl, unsigned char s)
1100 {
1101         unsigned char c;
1102
1103         if (s == 0x70) {
1104 #ifdef CONFIG_SLIP_SMART
1105                 /* drop keeptest bit = VSV */
1106                 if (test_bit(SLF_KEEPTEST, &sl->flags))
1107                         clear_bit(SLF_KEEPTEST, &sl->flags);
1108 #endif
1109
1110                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2))  {
1111                         sl_bump(sl);
1112                 }
1113                 sl->rcount = 0;
1114                 sl->xbits = 0;
1115                 sl->xdata = 0;
1116         } else if (s >= 0x30 && s < 0x70) {
1117                 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1118                 sl->xbits += 6;
1119                 if (sl->xbits >= 8) {
1120                         sl->xbits -= 8;
1121                         c = (unsigned char)(sl->xdata >> sl->xbits);
1122                         if (!test_bit(SLF_ERROR, &sl->flags))  {
1123                                 if (sl->rcount < sl->buffsize)  {
1124                                         sl->rbuff[sl->rcount++] = c;
1125                                         return;
1126                                 }
1127                                 sl->rx_over_errors++;
1128                                 set_bit(SLF_ERROR, &sl->flags);
1129                         }
1130                 }
1131         }
1132 }
1133 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1134
1135 /* Perform I/O control on an active SLIP channel. */
1136 static int slip_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
1137 {
1138         struct slip *sl = (struct slip *) tty->disc_data;
1139         unsigned int tmp;
1140         int __user *p = (int __user *)arg;
1141
1142         /* First make sure we're connected. */
1143         if (!sl || sl->magic != SLIP_MAGIC) {
1144                 return -EINVAL;
1145         }
1146
1147         switch(cmd) {
1148          case SIOCGIFNAME:
1149                 tmp = strlen(sl->dev->name) + 1;
1150                 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1151                         return -EFAULT;
1152                 return 0;
1153
1154         case SIOCGIFENCAP:
1155                 if (put_user(sl->mode, p))
1156                         return -EFAULT;
1157                 return 0;
1158
1159         case SIOCSIFENCAP:
1160                 if (get_user(tmp, p))
1161                         return -EFAULT;
1162 #ifndef SL_INCLUDE_CSLIP
1163                 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))  {
1164                         return -EINVAL;
1165                 }
1166 #else
1167                 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1168                     (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))  {
1169                         /* return -EINVAL; */
1170                         tmp &= ~SL_MODE_ADAPTIVE;
1171                 }
1172 #endif
1173 #ifndef CONFIG_SLIP_MODE_SLIP6
1174                 if (tmp & SL_MODE_SLIP6)  {
1175                         return -EINVAL;
1176                 }
1177 #endif
1178                 sl->mode = tmp;
1179                 sl->dev->type = ARPHRD_SLIP+sl->mode;
1180                 return 0;
1181
1182          case SIOCSIFHWADDR:
1183                 return -EINVAL;
1184
1185 #ifdef CONFIG_SLIP_SMART
1186         /* VSV changes start here */
1187         case SIOCSKEEPALIVE:
1188                 if (get_user(tmp, p))
1189                         return -EFAULT;
1190                 if (tmp > 255) /* max for unchar */
1191                         return -EINVAL;
1192
1193                 spin_lock_bh(&sl->lock);
1194                 if (!sl->tty) {
1195                         spin_unlock_bh(&sl->lock);
1196                         return -ENODEV;
1197                 }
1198                 if ((sl->keepalive = (unchar) tmp) != 0) {
1199                         mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1200                         set_bit(SLF_KEEPTEST, &sl->flags);
1201                 } else {
1202                         del_timer (&sl->keepalive_timer);
1203                 }
1204                 spin_unlock_bh(&sl->lock);
1205                 return 0;
1206
1207         case SIOCGKEEPALIVE:
1208                 if (put_user(sl->keepalive, p))
1209                         return -EFAULT;
1210                 return 0;
1211
1212         case SIOCSOUTFILL:
1213                 if (get_user(tmp, p))
1214                         return -EFAULT;
1215                 if (tmp > 255) /* max for unchar */
1216                         return -EINVAL;
1217                 spin_lock_bh(&sl->lock);
1218                 if (!sl->tty) {
1219                         spin_unlock_bh(&sl->lock);
1220                         return -ENODEV;
1221                 }
1222                 if ((sl->outfill = (unchar) tmp) != 0){
1223                         mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1224                         set_bit(SLF_OUTWAIT, &sl->flags);
1225                 } else {
1226                         del_timer (&sl->outfill_timer);
1227                 }
1228                 spin_unlock_bh(&sl->lock);
1229                 return 0;
1230
1231         case SIOCGOUTFILL:
1232                 if (put_user(sl->outfill, p))
1233                         return -EFAULT;
1234                 return 0;
1235         /* VSV changes end */
1236 #endif
1237
1238         /* Allow stty to read, but not set, the serial port */
1239         case TCGETS:
1240         case TCGETA:
1241                 return n_tty_ioctl(tty, file, cmd, arg);
1242
1243         default:
1244                 return -ENOIOCTLCMD;
1245         }
1246 }
1247
1248 /* VSV changes start here */
1249 #ifdef CONFIG_SLIP_SMART
1250 /* function do_ioctl called from net/core/dev.c
1251    to allow get/set outfill/keepalive parameter
1252    by ifconfig                                 */
1253
1254 static int sl_ioctl(struct net_device *dev,struct ifreq *rq,int cmd)
1255 {
1256         struct slip *sl = netdev_priv(dev);
1257         unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1258
1259         if (sl == NULL)         /* Allocation failed ?? */
1260                 return -ENODEV;
1261
1262         spin_lock_bh(&sl->lock);
1263
1264         if (!sl->tty) {
1265                 spin_unlock_bh(&sl->lock);
1266                 return -ENODEV;
1267         }
1268
1269         switch(cmd){
1270         case SIOCSKEEPALIVE:
1271                 /* max for unchar */
1272                 if ((unsigned)*p > 255) {
1273                         spin_unlock_bh(&sl->lock);
1274                         return -EINVAL;
1275                 }
1276                 sl->keepalive = (unchar) *p;
1277                 if (sl->keepalive != 0) {
1278                         sl->keepalive_timer.expires=jiffies+sl->keepalive*HZ;
1279                         mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1280                         set_bit(SLF_KEEPTEST, &sl->flags);
1281                 } else {
1282                         del_timer(&sl->keepalive_timer);
1283                 }
1284                 break;
1285
1286         case SIOCGKEEPALIVE:
1287                 *p = sl->keepalive;
1288                 break;
1289
1290         case SIOCSOUTFILL:
1291                 if ((unsigned)*p > 255) { /* max for unchar */
1292                         spin_unlock_bh(&sl->lock);
1293                         return -EINVAL;
1294                 }
1295                 if ((sl->outfill = (unchar)*p) != 0){
1296                         mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1297                         set_bit(SLF_OUTWAIT, &sl->flags);
1298                 } else {
1299                         del_timer (&sl->outfill_timer);
1300                 }
1301                 break;
1302
1303         case SIOCGOUTFILL:
1304                 *p = sl->outfill;
1305                 break;
1306
1307         case SIOCSLEASE:
1308                 /* Resolve race condition, when ioctl'ing hanged up
1309                    and opened by another process device.
1310                  */
1311                 if (sl->tty != current->signal->tty && sl->pid != current->pid) {
1312                         spin_unlock_bh(&sl->lock);
1313                         return -EPERM;
1314                 }
1315                 sl->leased = 0;
1316                 if (*p)
1317                         sl->leased = 1;
1318                 break;
1319
1320         case SIOCGLEASE:
1321                 *p = sl->leased;
1322         };
1323         spin_unlock_bh(&sl->lock);
1324         return 0;
1325 }
1326 #endif
1327 /* VSV changes end */
1328
1329 static struct tty_ldisc sl_ldisc = {
1330         .owner          = THIS_MODULE,
1331         .magic          = TTY_LDISC_MAGIC,
1332         .name           = "slip",
1333         .open           = slip_open,
1334         .close          = slip_close,
1335         .ioctl          = slip_ioctl,
1336         .receive_buf    = slip_receive_buf,
1337         .receive_room   = slip_receive_room,
1338         .write_wakeup   = slip_write_wakeup,
1339 };
1340
1341 static int __init slip_init(void)
1342 {
1343         int status;
1344
1345         if (slip_maxdev < 4)
1346                 slip_maxdev = 4; /* Sanity */
1347
1348         printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1349 #ifdef CONFIG_SLIP_MODE_SLIP6
1350                " (6 bit encapsulation enabled)"
1351 #endif
1352                ".\n",
1353                SLIP_VERSION, slip_maxdev );
1354 #if defined(SL_INCLUDE_CSLIP)
1355         printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1356 #endif
1357 #ifdef CONFIG_SLIP_SMART
1358         printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1359 #endif
1360
1361         slip_devs = kmalloc(sizeof(struct net_device *)*slip_maxdev, GFP_KERNEL);
1362         if (!slip_devs) {
1363                 printk(KERN_ERR "SLIP: Can't allocate slip devices array!  Uaargh! (-> No SLIP available)\n");
1364                 return -ENOMEM;
1365         }
1366
1367         /* Clear the pointer array, we allocate devices when we need them */
1368         memset(slip_devs, 0, sizeof(struct net_device *)*slip_maxdev);
1369
1370         /* Fill in our line protocol discipline, and register it */
1371         if ((status = tty_register_ldisc(N_SLIP, &sl_ldisc)) != 0)  {
1372                 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1373                 kfree(slip_devs);
1374         }
1375         return status;
1376 }
1377
1378 static void __exit slip_exit(void)
1379 {
1380         int i;
1381         struct net_device *dev;
1382         struct slip *sl;
1383         unsigned long timeout = jiffies + HZ;
1384         int busy = 0;
1385
1386         if (slip_devs == NULL)
1387                 return;
1388
1389         /* First of all: check for active disciplines and hangup them.
1390          */
1391         do {
1392                 if (busy) {
1393                         set_current_state(TASK_INTERRUPTIBLE);
1394                         schedule_timeout(HZ / 10);
1395                 }
1396
1397                 busy = 0;
1398                 for (i = 0; i < slip_maxdev; i++) {
1399                         dev = slip_devs[i];
1400                         if (!dev)
1401                                 continue;
1402                         sl = netdev_priv(dev);
1403                         spin_lock_bh(&sl->lock);
1404                         if (sl->tty) {
1405                                 busy++;
1406                                 tty_hangup(sl->tty);
1407                         }
1408                         spin_unlock_bh(&sl->lock);
1409                 }
1410         } while (busy && time_before(jiffies, timeout));
1411
1412
1413         for (i = 0; i < slip_maxdev; i++) {
1414                 dev = slip_devs[i];
1415                 if (!dev)
1416                         continue;
1417                 slip_devs[i] = NULL;
1418
1419                 sl = netdev_priv(dev);
1420                 if (sl->tty) {
1421                         printk(KERN_ERR "%s: tty discipline still running\n",
1422                                dev->name);
1423                         /* Intentionally leak the control block. */
1424                         dev->destructor = NULL;
1425                 }
1426
1427                 unregister_netdev(dev);
1428         }
1429
1430         kfree(slip_devs);
1431         slip_devs = NULL;
1432
1433         if ((i = tty_register_ldisc(N_SLIP, NULL)))
1434         {
1435                 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1436         }
1437 }
1438
1439 module_init(slip_init);
1440 module_exit(slip_exit);
1441
1442 #ifdef CONFIG_SLIP_SMART
1443 /*
1444  * This is start of the code for multislip style line checking
1445  * added by Stanislav Voronyi. All changes before marked VSV
1446  */
1447
1448 static void sl_outfill(unsigned long sls)
1449 {
1450         struct slip *sl=(struct slip *)sls;
1451
1452         spin_lock(&sl->lock);
1453
1454         if (sl->tty == NULL)
1455                 goto out;
1456
1457         if(sl->outfill)
1458         {
1459                 if( test_bit(SLF_OUTWAIT, &sl->flags) )
1460                 {
1461                         /* no packets were transmitted, do outfill */
1462 #ifdef CONFIG_SLIP_MODE_SLIP6
1463                         unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1464 #else
1465                         unsigned char s = END;
1466 #endif
1467                         /* put END into tty queue. Is it right ??? */
1468                         if (!netif_queue_stopped(sl->dev))
1469                         {
1470                                 /* if device busy no outfill */
1471                                 sl->tty->driver->write(sl->tty, &s, 1);
1472                         }
1473                 }
1474                 else
1475                         set_bit(SLF_OUTWAIT, &sl->flags);
1476
1477                 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1478         }
1479 out:
1480         spin_unlock(&sl->lock);
1481 }
1482
1483 static void sl_keepalive(unsigned long sls)
1484 {
1485         struct slip *sl=(struct slip *)sls;
1486
1487         spin_lock(&sl->lock);
1488
1489         if (sl->tty == NULL)
1490                 goto out;
1491
1492         if( sl->keepalive)
1493         {
1494                 if(test_bit(SLF_KEEPTEST, &sl->flags))
1495                 {
1496                         /* keepalive still high :(, we must hangup */
1497                         if( sl->outfill ) /* outfill timer must be deleted too */
1498                                 (void)del_timer(&sl->outfill_timer);
1499                         printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1500                         tty_hangup(sl->tty); /* this must hangup tty & close slip */
1501                         /* I think we need not something else */
1502                         goto out;
1503                 }
1504                 else
1505                         set_bit(SLF_KEEPTEST, &sl->flags);
1506
1507                 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1508         }
1509
1510 out:
1511         spin_unlock(&sl->lock);
1512 }
1513
1514 #endif
1515 MODULE_LICENSE("GPL");
1516 MODULE_ALIAS_LDISC(N_SLIP);