drivers/net/slip/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
  15  *                                      mtu upwards. Driver now spots this
  16  *                                      and grows/shrinks its buffers(hack!).
  17  *                                      Memory leak if you run out of memory
  18  *                                      setting up a slip driver fixed.
  19  *              Matt Dillon     :       Printable slip (borrowed from NET2E)
  20  *      Pauline Middelink       :       Slip driver fixes.
  21  *              Alan Cox        :       Honours the old SL_COMPRESSED flag
  22  *              Alan Cox        :       KISS AX.25 and AXUI IP support
  23  *              Michael Riepe   :       Automatic CSLIP recognition added
  24  *              Charles Hedrick :       CSLIP header length problem fix.
  25  *              Alan Cox        :       Corrected non-IP cases of the above.
  26  *              Alan Cox        :       Now uses hardware type as per FvK.
  27  *              Alan Cox        :       Default to 192.168.0.0 (RFC 1597)
  28  *              A.N.Kuznetsov   :       dev_tint() recursion fix.
  29  *      Dmitry Gorodchanin      :       SLIP memory leaks
  30  *      Dmitry Gorodchanin      :       Code cleanup. Reduce tty driver
  31  *                                      buffering from 4096 to 256 bytes.
  32  *                                      Improving SLIP response time.
  33  *                                      CONFIG_SLIP_MODE_SLIP6.
  34  *                                      ifconfig sl? up & down now works
  35  *                                      correctly.
  36  *                                      Modularization.
  37  *              Alan Cox        :       Oops - fix AX.25 buffer lengths
  38  *      Dmitry Gorodchanin      :       Even more cleanups. Preserve CSLIP
  39  *                                      statistics. Include CSLIP code only
  40  *                                      if it really needed.
  41  *              Alan Cox        :       Free slhc buffers in the right place.
  42  *              Alan Cox        :       Allow for digipeated IP over AX.25
  43  *              Matti Aarnio    :       Dynamic SLIP devices, with ideas taken
  44  *                                      from Jim Freeman's <jfree@caldera.com>
  45  *                                      dynamic PPP devices.  We do NOT kfree()
  46  *                                      device entries, just reg./unreg. them
  47  *                                      as they are needed.  We kfree() them
  48  *                                      at module cleanup.
  49  *                                      With MODULE-loading ``insmod'', user
  50  *                                      can issue parameter:  slip_maxdev=1024
  51  *                                      (Or how much he/she wants.. Default
  52  *                                      is 256)
  53  *      Stanislav Voronyi       :       Slip line checking, with ideas taken
  54  *                                      from multislip BSDI driver which was
  55  *                                      written by Igor Chechik, RELCOM Corp.
  56  *                                      Only algorithms have been ported to
  57  *                                      Linux SLIP driver.
  58  *      Vitaly E. Lavrov        :       Sane behaviour on tty hangup.
  59  *      Alexey Kuznetsov        :       Cleanup interfaces to tty & netdevice
  60  *                                      modules.
  61  */
  62
  63 #define SL_CHECK_TRANSMIT
  64 #include <linux/module.h>
  65 #include <linux/moduleparam.h>
  66
  67 #include <asm/uaccess.h>
  68 #include <linux/bitops.h>
  69 #include <linux/sched.h>
  70 #include <linux/string.h>
  71 #include <linux/mm.h>
  72 #include <linux/interrupt.h>
  73 #include <linux/in.h>
  74 #include <linux/tty.h>
  75 #include <linux/errno.h>
  76 #include <linux/netdevice.h>
  77 #include <linux/etherdevice.h>
  78 #include <linux/skbuff.h>
  79 #include <linux/rtnetlink.h>
  80 #include <linux/if_arp.h>
  81 #include <linux/if_slip.h>
  82 #include <linux/compat.h>
  83 #include <linux/delay.h>
  84 #include <linux/init.h>
  85 #include <linux/slab.h>
  86 #include <linux/workqueue.h>
  87 #include "slip.h"
  88 #ifdef CONFIG_INET
  89 #include <linux/ip.h>
  90 #include <linux/tcp.h>
  91 #include <net/slhc_vj.h>
  92 #endif
  93
  94 #define SLIP_VERSION    "0.8.4-NET3.019-NEWTTY"
  95
  96 static struct net_device **slip_devs;
  97
  98 static int slip_maxdev = SL_NRUNIT;
  99 module_param(slip_maxdev, int, 0);
 100 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
 101
 102 static int slip_esc(unsigned char *p, unsigned char *d, int len);
 103 static void slip_unesc(struct slip *sl, unsigned char c);
 104 #ifdef CONFIG_SLIP_MODE_SLIP6
 105 static int slip_esc6(unsigned char *p, unsigned char *d, int len);
 106 static void slip_unesc6(struct slip *sl, unsigned char c);
 107 #endif
 108 #ifdef CONFIG_SLIP_SMART
 109 static void sl_keepalive(unsigned long sls);
 110 static void sl_outfill(unsigned long sls);
 111 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
 112 #endif
 113
 114 /********************************
 115 *  Buffer administration routines:
 116 *       sl_alloc_bufs()
 117 *       sl_free_bufs()
 118 *       sl_realloc_bufs()
 119 *
 120 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because
 121 *       sl_realloc_bufs provides strong atomicity and reallocation
 122 *       on actively running device.
 123 *********************************/
 124
 125 /*
 126    Allocate channel buffers.
 127  */
 128
 129 static int sl_alloc_bufs(struct slip *sl, int mtu)
 130 {
 131         int err = -ENOBUFS;
 132         unsigned long len;
 133         char *rbuff = NULL;
 134         char *xbuff = NULL;
 135 #ifdef SL_INCLUDE_CSLIP
 136         char *cbuff = NULL;
 137         struct slcompress *slcomp = NULL;
 138 #endif
 139
 140         /*
 141          * Allocate the SLIP frame buffers:
 142          *
 143          * rbuff        Receive buffer.
 144          * xbuff        Transmit buffer.
 145          * cbuff        Temporary compression buffer.
 146          */
 147         len = mtu * 2;
 148
 149         /*
 150          * allow for arrival of larger UDP packets, even if we say not to
 151          * also fixes a bug in which SunOS sends 512-byte packets even with
 152          * an MSS of 128
 153          */
 154         if (len < 576 * 2)
 155                 len = 576 * 2;
 156         rbuff = kmalloc(len + 4, GFP_KERNEL);
 157         if (rbuff == NULL)
 158                 goto err_exit;
 159         xbuff = kmalloc(len + 4, GFP_KERNEL);
 160         if (xbuff == NULL)
 161                 goto err_exit;
 162 #ifdef SL_INCLUDE_CSLIP
 163         cbuff = kmalloc(len + 4, GFP_KERNEL);
 164         if (cbuff == NULL)
 165                 goto err_exit;
 166         slcomp = slhc_init(16, 16);
 167         if (IS_ERR(slcomp))
 168                 goto err_exit;
 169 #endif
 170         spin_lock_bh(&sl->lock);
 171         if (sl->tty == NULL) {
 172                 spin_unlock_bh(&sl->lock);
 173                 err = -ENODEV;
 174                 goto err_exit;
 175         }
 176         sl->mtu      = mtu;
 177         sl->buffsize = len;
 178         sl->rcount   = 0;
 179         sl->xleft    = 0;
 180         rbuff = xchg(&sl->rbuff, rbuff);
 181         xbuff = xchg(&sl->xbuff, xbuff);
 182 #ifdef SL_INCLUDE_CSLIP
 183         cbuff = xchg(&sl->cbuff, cbuff);
 184         slcomp = xchg(&sl->slcomp, slcomp);
 185 #endif
 186 #ifdef CONFIG_SLIP_MODE_SLIP6
 187         sl->xdata    = 0;
 188         sl->xbits    = 0;
 189 #endif
 190         spin_unlock_bh(&sl->lock);
 191         err = 0;
 192
 193         /* Cleanup */
 194 err_exit:
 195 #ifdef SL_INCLUDE_CSLIP
 196         kfree(cbuff);
 197         slhc_free(slcomp);
 198 #endif
 199         kfree(xbuff);
 200         kfree(rbuff);
 201         return err;
 202 }
 203
 204 /* Free a SLIP channel buffers. */
 205 static void sl_free_bufs(struct slip *sl)
 206 {
 207         /* Free all SLIP frame buffers. */
 208         kfree(xchg(&sl->rbuff, NULL));
 209         kfree(xchg(&sl->xbuff, NULL));
 210 #ifdef SL_INCLUDE_CSLIP
 211         kfree(xchg(&sl->cbuff, NULL));
 212         slhc_free(xchg(&sl->slcomp, NULL));
 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 = kmalloc(len + 4, GFP_ATOMIC);
 239         rbuff = kmalloc(len + 4, GFP_ATOMIC);
 240 #ifdef SL_INCLUDE_CSLIP
 241         cbuff = 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         spin_lock_bh(&sl->lock);
 258
 259         err = -ENODEV;
 260         if (sl->tty == NULL)
 261                 goto done_on_bh;
 262
 263         xbuff    = xchg(&sl->xbuff, xbuff);
 264         rbuff    = xchg(&sl->rbuff, rbuff);
 265 #ifdef SL_INCLUDE_CSLIP
 266         cbuff    = xchg(&sl->cbuff, cbuff);
 267 #endif
 268         if (sl->xleft)  {
 269                 if (sl->xleft <= len)  {
 270                         memcpy(sl->xbuff, sl->xhead, sl->xleft);
 271                 } else  {
 272                         sl->xleft = 0;
 273                         dev->stats.tx_dropped++;
 274                 }
 275         }
 276         sl->xhead = sl->xbuff;
 277
 278         if (sl->rcount)  {
 279                 if (sl->rcount <= len) {
 280                         memcpy(sl->rbuff, rbuff, sl->rcount);
 281                 } else  {
 282                         sl->rcount = 0;
 283                         dev->stats.rx_over_errors++;
 284                         set_bit(SLF_ERROR, &sl->flags);
 285                 }
 286         }
 287         sl->mtu      = mtu;
 288         dev->mtu      = mtu;
 289         sl->buffsize = len;
 290         err = 0;
 291
 292 done_on_bh:
 293         spin_unlock_bh(&sl->lock);
 294
 295 done:
 296         kfree(xbuff);
 297         kfree(rbuff);
 298 #ifdef SL_INCLUDE_CSLIP
 299         kfree(cbuff);
 300 #endif
 301         return err;
 302 }
 303
 304
 305 /* Set the "sending" flag.  This must be atomic hence the set_bit. */
 306 static inline void sl_lock(struct slip *sl)
 307 {
 308         netif_stop_queue(sl->dev);
 309 }
 310
 311
 312 /* Clear the "sending" flag.  This must be atomic, hence the ASM. */
 313 static inline void sl_unlock(struct slip *sl)
 314 {
 315         netif_wake_queue(sl->dev);
 316 }
 317
 318 /* Send one completely decapsulated IP datagram to the IP layer. */
 319 static void sl_bump(struct slip *sl)
 320 {
 321         struct net_device *dev = sl->dev;
 322         struct sk_buff *skb;
 323         int count;
 324
 325         count = sl->rcount;
 326 #ifdef SL_INCLUDE_CSLIP
 327         if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
 328                 unsigned char c = sl->rbuff[0];
 329                 if (c & SL_TYPE_COMPRESSED_TCP) {
 330                         /* ignore compressed packets when CSLIP is off */
 331                         if (!(sl->mode & SL_MODE_CSLIP)) {
 332                                 printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name);
 333                                 return;
 334                         }
 335                         /* make sure we've reserved enough space for uncompress
 336                            to use */
 337                         if (count + 80 > sl->buffsize) {
 338                                 dev->stats.rx_over_errors++;
 339                                 return;
 340                         }
 341                         count = slhc_uncompress(sl->slcomp, sl->rbuff, count);
 342                         if (count <= 0)
 343                                 return;
 344                 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {
 345                         if (!(sl->mode & SL_MODE_CSLIP)) {
 346                                 /* turn on header compression */
 347                                 sl->mode |= SL_MODE_CSLIP;
 348                                 sl->mode &= ~SL_MODE_ADAPTIVE;
 349                                 printk(KERN_INFO "%s: header compression turned on\n", dev->name);
 350                         }
 351                         sl->rbuff[0] &= 0x4f;
 352                         if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0)
 353                                 return;
 354                 }
 355         }
 356 #endif  /* SL_INCLUDE_CSLIP */
 357
 358         dev->stats.rx_bytes += count;
 359
 360         skb = dev_alloc_skb(count);
 361         if (skb == NULL) {
 362                 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name);
 363                 dev->stats.rx_dropped++;
 364                 return;
 365         }
 366         skb->dev = dev;
 367         memcpy(skb_put(skb, count), sl->rbuff, count);
 368         skb_reset_mac_header(skb);
 369         skb->protocol = htons(ETH_P_IP);
 370         netif_rx_ni(skb);
 371         dev->stats.rx_packets++;
 372 }
 373
 374 /* Encapsulate one IP datagram and stuff into a TTY queue. */
 375 static void sl_encaps(struct slip *sl, unsigned char *icp, int len)
 376 {
 377         unsigned char *p;
 378         int actual, count;
 379
 380         if (len > sl->mtu) {            /* Sigh, shouldn't occur BUT ... */
 381                 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name);
 382                 sl->dev->stats.tx_dropped++;
 383                 sl_unlock(sl);
 384                 return;
 385         }
 386
 387         p = icp;
 388 #ifdef SL_INCLUDE_CSLIP
 389         if (sl->mode & SL_MODE_CSLIP)
 390                 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);
 391 #endif
 392 #ifdef CONFIG_SLIP_MODE_SLIP6
 393         if (sl->mode & SL_MODE_SLIP6)
 394                 count = slip_esc6(p, sl->xbuff, len);
 395         else
 396 #endif
 397                 count = slip_esc(p, sl->xbuff, len);
 398
 399         /* Order of next two lines is *very* important.
 400          * When we are sending a little amount of data,
 401          * the transfer may be completed inside the ops->write()
 402          * routine, because it's running with interrupts enabled.
 403          * In this case we *never* got WRITE_WAKEUP event,
 404          * if we did not request it before write operation.
 405          *       14 Oct 1994  Dmitry Gorodchanin.
 406          */
 407         set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 408         actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
 409 #ifdef SL_CHECK_TRANSMIT
 410         sl->dev->trans_start = jiffies;
 411 #endif
 412         sl->xleft = count - actual;
 413         sl->xhead = sl->xbuff + actual;
 414 #ifdef CONFIG_SLIP_SMART
 415         /* VSV */
 416         clear_bit(SLF_OUTWAIT, &sl->flags);     /* reset outfill flag */
 417 #endif
 418 }
 419
 420 /* Write out any remaining transmit buffer. Scheduled when tty is writable */
 421 static void slip_transmit(struct work_struct *work)
 422 {
 423         struct slip *sl = container_of(work, struct slip, tx_work);
 424         int actual;
 425
 426         spin_lock_bh(&sl->lock);
 427         /* First make sure we're connected. */
 428         if (!sl->tty || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) {
 429                 spin_unlock_bh(&sl->lock);
 430                 return;
 431         }
 432
 433         if (sl->xleft <= 0)  {
 434                 /* Now serial buffer is almost free & we can start
 435                  * transmission of another packet */
 436                 sl->dev->stats.tx_packets++;
 437                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 438                 spin_unlock_bh(&sl->lock);
 439                 sl_unlock(sl);
 440                 return;
 441         }
 442
 443         actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
 444         sl->xleft -= actual;
 445         sl->xhead += actual;
 446         spin_unlock_bh(&sl->lock);
 447 }
 448
 449 /*
 450  * Called by the driver when there's room for more data.
 451  * Schedule the transmit.
 452  */
 453 static void slip_write_wakeup(struct tty_struct *tty)
 454 {
 455         struct slip *sl = tty->disc_data;
 456
 457         schedule_work(&sl->tx_work);
 458 }
 459
 460 static void sl_tx_timeout(struct net_device *dev)
 461 {
 462         struct slip *sl = netdev_priv(dev);
 463
 464         spin_lock(&sl->lock);
 465
 466         if (netif_queue_stopped(dev)) {
 467                 if (!netif_running(dev))
 468                         goto out;
 469
 470                 /* May be we must check transmitter timeout here ?
 471                  *      14 Oct 1994 Dmitry Gorodchanin.
 472                  */
 473 #ifdef SL_CHECK_TRANSMIT
 474                 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ))  {
 475                         /* 20 sec timeout not reached */
 476                         goto out;
 477                 }
 478                 printk(KERN_WARNING "%s: transmit timed out, %s?\n",
 479                         dev->name,
 480                         (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
 481                                 "bad line quality" : "driver error");
 482                 sl->xleft = 0;
 483                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 484                 sl_unlock(sl);
 485 #endif
 486         }
 487 out:
 488         spin_unlock(&sl->lock);
 489 }
 490
 491
 492 /* Encapsulate an IP datagram and kick it into a TTY queue. */
 493 static netdev_tx_t
 494 sl_xmit(struct sk_buff *skb, struct net_device *dev)
 495 {
 496         struct slip *sl = netdev_priv(dev);
 497
 498         spin_lock(&sl->lock);
 499         if (!netif_running(dev)) {
 500                 spin_unlock(&sl->lock);
 501                 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
 502                 dev_kfree_skb(skb);
 503                 return NETDEV_TX_OK;
 504         }
 505         if (sl->tty == NULL) {
 506                 spin_unlock(&sl->lock);
 507                 dev_kfree_skb(skb);
 508                 return NETDEV_TX_OK;
 509         }
 510
 511         sl_lock(sl);
 512         dev->stats.tx_bytes += skb->len;
 513         sl_encaps(sl, skb->data, skb->len);
 514         spin_unlock(&sl->lock);
 515
 516         dev_kfree_skb(skb);
 517         return NETDEV_TX_OK;
 518 }
 519
 520
 521 /******************************************
 522  *   Routines looking at netdevice side.
 523  ******************************************/
 524
 525 /* Netdevice UP -> DOWN routine */
 526
 527 static int
 528 sl_close(struct net_device *dev)
 529 {
 530         struct slip *sl = netdev_priv(dev);
 531
 532         spin_lock_bh(&sl->lock);
 533         if (sl->tty)
 534                 /* TTY discipline is running. */
 535                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
 536         netif_stop_queue(dev);
 537         sl->rcount   = 0;
 538         sl->xleft    = 0;
 539         spin_unlock_bh(&sl->lock);
 540
 541         return 0;
 542 }
 543
 544 /* Netdevice DOWN -> UP routine */
 545
 546 static int sl_open(struct net_device *dev)
 547 {
 548         struct slip *sl = netdev_priv(dev);
 549
 550         if (sl->tty == NULL)
 551                 return -ENODEV;
 552
 553         sl->flags &= (1 << SLF_INUSE);
 554         netif_start_queue(dev);
 555         return 0;
 556 }
 557
 558 /* Netdevice change MTU request */
 559
 560 static int sl_change_mtu(struct net_device *dev, int new_mtu)
 561 {
 562         struct slip *sl = netdev_priv(dev);
 563
 564         if (new_mtu < 68 || new_mtu > 65534)
 565                 return -EINVAL;
 566
 567         if (new_mtu != dev->mtu)
 568                 return sl_realloc_bufs(sl, new_mtu);
 569         return 0;
 570 }
 571
 572 /* Netdevice get statistics request */
 573
 574 static struct rtnl_link_stats64 *
 575 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 576 {
 577         struct net_device_stats *devstats = &dev->stats;
 578 #ifdef SL_INCLUDE_CSLIP
 579         struct slip *sl = netdev_priv(dev);
 580         struct slcompress *comp = sl->slcomp;
 581 #endif
 582         stats->rx_packets     = devstats->rx_packets;
 583         stats->tx_packets     = devstats->tx_packets;
 584         stats->rx_bytes       = devstats->rx_bytes;
 585         stats->tx_bytes       = devstats->tx_bytes;
 586         stats->rx_dropped     = devstats->rx_dropped;
 587         stats->tx_dropped     = devstats->tx_dropped;
 588         stats->tx_errors      = devstats->tx_errors;
 589         stats->rx_errors      = devstats->rx_errors;
 590         stats->rx_over_errors = devstats->rx_over_errors;
 591
 592 #ifdef SL_INCLUDE_CSLIP
 593         if (comp) {
 594                 /* Generic compressed statistics */
 595                 stats->rx_compressed   = comp->sls_i_compressed;
 596                 stats->tx_compressed   = comp->sls_o_compressed;
 597
 598                 /* Are we really still needs this? */
 599                 stats->rx_fifo_errors += comp->sls_i_compressed;
 600                 stats->rx_dropped     += comp->sls_i_tossed;
 601                 stats->tx_fifo_errors += comp->sls_o_compressed;
 602                 stats->collisions     += comp->sls_o_misses;
 603         }
 604 #endif
 605         return stats;
 606 }
 607
 608 /* Netdevice register callback */
 609
 610 static int sl_init(struct net_device *dev)
 611 {
 612         struct slip *sl = netdev_priv(dev);
 613
 614         /*
 615          *      Finish setting up the DEVICE info.
 616          */
 617
 618         dev->mtu                = sl->mtu;
 619         dev->type               = ARPHRD_SLIP + sl->mode;
 620 #ifdef SL_CHECK_TRANSMIT
 621         dev->watchdog_timeo     = 20*HZ;
 622 #endif
 623         return 0;
 624 }
 625
 626
 627 static void sl_uninit(struct net_device *dev)
 628 {
 629         struct slip *sl = netdev_priv(dev);
 630
 631         sl_free_bufs(sl);
 632 }
 633
 634 /* Hook the destructor so we can free slip devices at the right point in time */
 635 static void sl_free_netdev(struct net_device *dev)
 636 {
 637         int i = dev->base_addr;
 638         free_netdev(dev);
 639         slip_devs[i] = NULL;
 640 }
 641
 642 static const struct net_device_ops sl_netdev_ops = {
 643         .ndo_init               = sl_init,
 644         .ndo_uninit             = sl_uninit,
 645         .ndo_open               = sl_open,
 646         .ndo_stop               = sl_close,
 647         .ndo_start_xmit         = sl_xmit,
 648         .ndo_get_stats64        = sl_get_stats64,
 649         .ndo_change_mtu         = sl_change_mtu,
 650         .ndo_tx_timeout         = sl_tx_timeout,
 651 #ifdef CONFIG_SLIP_SMART
 652         .ndo_do_ioctl           = sl_ioctl,
 653 #endif
 654 };
 655
 656
 657 static void sl_setup(struct net_device *dev)
 658 {
 659         dev->netdev_ops         = &sl_netdev_ops;
 660         dev->destructor         = sl_free_netdev;
 661
 662         dev->hard_header_len    = 0;
 663         dev->addr_len           = 0;
 664         dev->tx_queue_len       = 10;
 665
 666         /* New-style flags. */
 667         dev->flags              = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
 668 }
 669
 670 /******************************************
 671   Routines looking at TTY side.
 672  ******************************************/
 673
 674
 675 /*
 676  * Handle the 'receiver data ready' interrupt.
 677  * This function is called by the 'tty_io' module in the kernel when
 678  * a block of SLIP data has been received, which can now be decapsulated
 679  * and sent on to some IP layer for further processing. This will not
 680  * be re-entered while running but other ldisc functions may be called
 681  * in parallel
 682  */
 683
 684 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 685                                                         char *fp, int count)
 686 {
 687         struct slip *sl = tty->disc_data;
 688
 689         if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
 690                 return;
 691
 692         /* Read the characters out of the buffer */
 693         while (count--) {
 694                 if (fp && *fp++) {
 695                         if (!test_and_set_bit(SLF_ERROR, &sl->flags))
 696                                 sl->dev->stats.rx_errors++;
 697                         cp++;
 698                         continue;
 699                 }
 700 #ifdef CONFIG_SLIP_MODE_SLIP6
 701                 if (sl->mode & SL_MODE_SLIP6)
 702                         slip_unesc6(sl, *cp++);
 703                 else
 704 #endif
 705                         slip_unesc(sl, *cp++);
 706         }
 707 }
 708
 709 /************************************
 710  *  slip_open helper routines.
 711  ************************************/
 712
 713 /* Collect hanged up channels */
 714 static void sl_sync(void)
 715 {
 716         int i;
 717         struct net_device *dev;
 718         struct slip       *sl;
 719
 720         for (i = 0; i < slip_maxdev; i++) {
 721                 dev = slip_devs[i];
 722                 if (dev == NULL)
 723                         break;
 724
 725                 sl = netdev_priv(dev);
 726                 if (sl->tty || sl->leased)
 727                         continue;
 728                 if (dev->flags & IFF_UP)
 729                         dev_close(dev);
 730         }
 731 }
 732
 733
 734 /* Find a free SLIP channel, and link in this `tty' line. */
 735 static struct slip *sl_alloc(dev_t line)
 736 {
 737         int i;
 738         char name[IFNAMSIZ];
 739         struct net_device *dev = NULL;
 740         struct slip       *sl;
 741
 742         for (i = 0; i < slip_maxdev; i++) {
 743                 dev = slip_devs[i];
 744                 if (dev == NULL)
 745                         break;
 746         }
 747         /* Sorry, too many, all slots in use */
 748         if (i >= slip_maxdev)
 749                 return NULL;
 750
 751         sprintf(name, "sl%d", i);
 752         dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup);
 753         if (!dev)
 754                 return NULL;
 755
 756         dev->base_addr  = i;
 757         sl = netdev_priv(dev);
 758
 759         /* Initialize channel control data */
 760         sl->magic       = SLIP_MAGIC;
 761         sl->dev         = dev;
 762         spin_lock_init(&sl->lock);
 763         INIT_WORK(&sl->tx_work, slip_transmit);
 764         sl->mode        = SL_MODE_DEFAULT;
 765 #ifdef CONFIG_SLIP_SMART
 766         /* initialize timer_list struct */
 767         init_timer(&sl->keepalive_timer);
 768         sl->keepalive_timer.data = (unsigned long)sl;
 769         sl->keepalive_timer.function = sl_keepalive;
 770         init_timer(&sl->outfill_timer);
 771         sl->outfill_timer.data = (unsigned long)sl;
 772         sl->outfill_timer.function = sl_outfill;
 773 #endif
 774         slip_devs[i] = dev;
 775         return sl;
 776 }
 777
 778 /*
 779  * Open the high-level part of the SLIP channel.
 780  * This function is called by the TTY module when the
 781  * SLIP line discipline is called for.  Because we are
 782  * sure the tty line exists, we only have to link it to
 783  * a free SLIP channel...
 784  *
 785  * Called in process context serialized from other ldisc calls.
 786  */
 787
 788 static int slip_open(struct tty_struct *tty)
 789 {
 790         struct slip *sl;
 791         int err;
 792
 793         if (!capable(CAP_NET_ADMIN))
 794                 return -EPERM;
 795
 796         if (tty->ops->write == NULL)
 797                 return -EOPNOTSUPP;
 798
 799         /* RTnetlink lock is misused here to serialize concurrent
 800            opens of slip channels. There are better ways, but it is
 801            the simplest one.
 802          */
 803         rtnl_lock();
 804
 805         /* Collect hanged up channels. */
 806         sl_sync();
 807
 808         sl = tty->disc_data;
 809
 810         err = -EEXIST;
 811         /* First make sure we're not already connected. */
 812         if (sl && sl->magic == SLIP_MAGIC)
 813                 goto err_exit;
 814
 815         /* OK.  Find a free SLIP channel to use. */
 816         err = -ENFILE;
 817         sl = sl_alloc(tty_devnum(tty));
 818         if (sl == NULL)
 819                 goto err_exit;
 820
 821         sl->tty = tty;
 822         tty->disc_data = sl;
 823         sl->pid = current->pid;
 824
 825         if (!test_bit(SLF_INUSE, &sl->flags)) {
 826                 /* Perform the low-level SLIP initialization. */
 827                 err = sl_alloc_bufs(sl, SL_MTU);
 828                 if (err)
 829                         goto err_free_chan;
 830
 831                 set_bit(SLF_INUSE, &sl->flags);
 832
 833                 err = register_netdevice(sl->dev);
 834                 if (err)
 835                         goto err_free_bufs;
 836         }
 837
 838 #ifdef CONFIG_SLIP_SMART
 839         if (sl->keepalive) {
 840                 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;
 841                 add_timer(&sl->keepalive_timer);
 842         }
 843         if (sl->outfill) {
 844                 sl->outfill_timer.expires = jiffies + sl->outfill * HZ;
 845                 add_timer(&sl->outfill_timer);
 846         }
 847 #endif
 848
 849         /* Done.  We have linked the TTY line to a channel. */
 850         rtnl_unlock();
 851         tty->receive_room = 65536;      /* We don't flow control */
 852
 853         /* TTY layer expects 0 on success */
 854         return 0;
 855
 856 err_free_bufs:
 857         sl_free_bufs(sl);
 858
 859 err_free_chan:
 860         sl->tty = NULL;
 861         tty->disc_data = NULL;
 862         clear_bit(SLF_INUSE, &sl->flags);
 863
 864 err_exit:
 865         rtnl_unlock();
 866
 867         /* Count references from TTY module */
 868         return err;
 869 }
 870
 871 /*
 872  * Close down a SLIP channel.
 873  * This means flushing out any pending queues, and then returning. This
 874  * call is serialized against other ldisc functions.
 875  *
 876  * We also use this method fo a hangup event
 877  */
 878
 879 static void slip_close(struct tty_struct *tty)
 880 {
 881         struct slip *sl = tty->disc_data;
 882
 883         /* First make sure we're connected. */
 884         if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
 885                 return;
 886
 887         spin_lock_bh(&sl->lock);
 888         tty->disc_data = NULL;
 889         sl->tty = NULL;
 890         spin_unlock_bh(&sl->lock);
 891
 892         flush_work(&sl->tx_work);
 893
 894         /* VSV = very important to remove timers */
 895 #ifdef CONFIG_SLIP_SMART
 896         del_timer_sync(&sl->keepalive_timer);
 897         del_timer_sync(&sl->outfill_timer);
 898 #endif
 899         /* Flush network side */
 900         unregister_netdev(sl->dev);
 901         /* This will complete via sl_free_netdev */
 902 }
 903
 904 static int slip_hangup(struct tty_struct *tty)
 905 {
 906         slip_close(tty);
 907         return 0;
 908 }
 909  /************************************************************************
 910   *                     STANDARD SLIP ENCAPSULATION                      *
 911   ************************************************************************/
 912
 913 static int slip_esc(unsigned char *s, unsigned char *d, int len)
 914 {
 915         unsigned char *ptr = d;
 916         unsigned char c;
 917
 918         /*
 919          * Send an initial END character to flush out any
 920          * data that may have accumulated in the receiver
 921          * due to line noise.
 922          */
 923
 924         *ptr++ = END;
 925
 926         /*
 927          * For each byte in the packet, send the appropriate
 928          * character sequence, according to the SLIP protocol.
 929          */
 930
 931         while (len-- > 0) {
 932                 switch (c = *s++) {
 933                 case END:
 934                         *ptr++ = ESC;
 935                         *ptr++ = ESC_END;
 936                         break;
 937                 case ESC:
 938                         *ptr++ = ESC;
 939                         *ptr++ = ESC_ESC;
 940                         break;
 941                 default:
 942                         *ptr++ = c;
 943                         break;
 944                 }
 945         }
 946         *ptr++ = END;
 947         return ptr - d;
 948 }
 949
 950 static void slip_unesc(struct slip *sl, unsigned char s)
 951 {
 952
 953         switch (s) {
 954         case END:
 955 #ifdef CONFIG_SLIP_SMART
 956                 /* drop keeptest bit = VSV */
 957                 if (test_bit(SLF_KEEPTEST, &sl->flags))
 958                         clear_bit(SLF_KEEPTEST, &sl->flags);
 959 #endif
 960
 961                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
 962                     (sl->rcount > 2))
 963                         sl_bump(sl);
 964                 clear_bit(SLF_ESCAPE, &sl->flags);
 965                 sl->rcount = 0;
 966                 return;
 967
 968         case ESC:
 969                 set_bit(SLF_ESCAPE, &sl->flags);
 970                 return;
 971         case ESC_ESC:
 972                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
 973                         s = ESC;
 974                 break;
 975         case ESC_END:
 976                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
 977                         s = END;
 978                 break;
 979         }
 980         if (!test_bit(SLF_ERROR, &sl->flags))  {
 981                 if (sl->rcount < sl->buffsize)  {
 982                         sl->rbuff[sl->rcount++] = s;
 983                         return;
 984                 }
 985                 sl->dev->stats.rx_over_errors++;
 986                 set_bit(SLF_ERROR, &sl->flags);
 987         }
 988 }
 989
 990
 991 #ifdef CONFIG_SLIP_MODE_SLIP6
 992 /************************************************************************
 993  *                       6 BIT SLIP ENCAPSULATION                       *
 994  ************************************************************************/
 995
 996 static int slip_esc6(unsigned char *s, unsigned char *d, int len)
 997 {
 998         unsigned char *ptr = d;
 999         unsigned char c;
1000         int i;
1001         unsigned short v = 0;
1002         short bits = 0;
1003
1004         /*
1005          * Send an initial END character to flush out any
1006          * data that may have accumulated in the receiver
1007          * due to line noise.
1008          */
1009
1010         *ptr++ = 0x70;
1011
1012         /*
1013          * Encode the packet into printable ascii characters
1014          */
1015
1016         for (i = 0; i < len; ++i) {
1017                 v = (v << 8) | s[i];
1018                 bits += 8;
1019                 while (bits >= 6) {
1020                         bits -= 6;
1021                         c = 0x30 + ((v >> bits) & 0x3F);
1022                         *ptr++ = c;
1023                 }
1024         }
1025         if (bits) {
1026                 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1027                 *ptr++ = c;
1028         }
1029         *ptr++ = 0x70;
1030         return ptr - d;
1031 }
1032
1033 static void slip_unesc6(struct slip *sl, unsigned char s)
1034 {
1035         unsigned char c;
1036
1037         if (s == 0x70) {
1038 #ifdef CONFIG_SLIP_SMART
1039                 /* drop keeptest bit = VSV */
1040                 if (test_bit(SLF_KEEPTEST, &sl->flags))
1041                         clear_bit(SLF_KEEPTEST, &sl->flags);
1042 #endif
1043
1044                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
1045                     (sl->rcount > 2))
1046                         sl_bump(sl);
1047                 sl->rcount = 0;
1048                 sl->xbits = 0;
1049                 sl->xdata = 0;
1050         } else if (s >= 0x30 && s < 0x70) {
1051                 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1052                 sl->xbits += 6;
1053                 if (sl->xbits >= 8) {
1054                         sl->xbits -= 8;
1055                         c = (unsigned char)(sl->xdata >> sl->xbits);
1056                         if (!test_bit(SLF_ERROR, &sl->flags))  {
1057                                 if (sl->rcount < sl->buffsize)  {
1058                                         sl->rbuff[sl->rcount++] = c;
1059                                         return;
1060                                 }
1061                                 sl->dev->stats.rx_over_errors++;
1062                                 set_bit(SLF_ERROR, &sl->flags);
1063                         }
1064                 }
1065         }
1066 }
1067 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1068
1069 /* Perform I/O control on an active SLIP channel. */
1070 static int slip_ioctl(struct tty_struct *tty, struct file *file,
1071                                         unsigned int cmd, unsigned long arg)
1072 {
1073         struct slip *sl = tty->disc_data;
1074         unsigned int tmp;
1075         int __user *p = (int __user *)arg;
1076
1077         /* First make sure we're connected. */
1078         if (!sl || sl->magic != SLIP_MAGIC)
1079                 return -EINVAL;
1080
1081         switch (cmd) {
1082         case SIOCGIFNAME:
1083                 tmp = strlen(sl->dev->name) + 1;
1084                 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1085                         return -EFAULT;
1086                 return 0;
1087
1088         case SIOCGIFENCAP:
1089                 if (put_user(sl->mode, p))
1090                         return -EFAULT;
1091                 return 0;
1092
1093         case SIOCSIFENCAP:
1094                 if (get_user(tmp, p))
1095                         return -EFAULT;
1096 #ifndef SL_INCLUDE_CSLIP
1097                 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
1098                         return -EINVAL;
1099 #else
1100                 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1101                     (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
1102                         /* return -EINVAL; */
1103                         tmp &= ~SL_MODE_ADAPTIVE;
1104 #endif
1105 #ifndef CONFIG_SLIP_MODE_SLIP6
1106                 if (tmp & SL_MODE_SLIP6)
1107                         return -EINVAL;
1108 #endif
1109                 sl->mode = tmp;
1110                 sl->dev->type = ARPHRD_SLIP + sl->mode;
1111                 return 0;
1112
1113         case SIOCSIFHWADDR:
1114                 return -EINVAL;
1115
1116 #ifdef CONFIG_SLIP_SMART
1117         /* VSV changes start here */
1118         case SIOCSKEEPALIVE:
1119                 if (get_user(tmp, p))
1120                         return -EFAULT;
1121                 if (tmp > 255) /* max for unchar */
1122                         return -EINVAL;
1123
1124                 spin_lock_bh(&sl->lock);
1125                 if (!sl->tty) {
1126                         spin_unlock_bh(&sl->lock);
1127                         return -ENODEV;
1128                 }
1129                 sl->keepalive = (u8)tmp;
1130                 if (sl->keepalive != 0) {
1131                         mod_timer(&sl->keepalive_timer,
1132                                         jiffies + sl->keepalive * HZ);
1133                         set_bit(SLF_KEEPTEST, &sl->flags);
1134                 } else
1135                         del_timer(&sl->keepalive_timer);
1136                 spin_unlock_bh(&sl->lock);
1137                 return 0;
1138
1139         case SIOCGKEEPALIVE:
1140                 if (put_user(sl->keepalive, p))
1141                         return -EFAULT;
1142                 return 0;
1143
1144         case SIOCSOUTFILL:
1145                 if (get_user(tmp, p))
1146                         return -EFAULT;
1147                 if (tmp > 255) /* max for unchar */
1148                         return -EINVAL;
1149                 spin_lock_bh(&sl->lock);
1150                 if (!sl->tty) {
1151                         spin_unlock_bh(&sl->lock);
1152                         return -ENODEV;
1153                 }
1154                 sl->outfill = (u8)tmp;
1155                 if (sl->outfill != 0) {
1156                         mod_timer(&sl->outfill_timer,
1157                                                 jiffies + sl->outfill * HZ);
1158                         set_bit(SLF_OUTWAIT, &sl->flags);
1159                 } else
1160                         del_timer(&sl->outfill_timer);
1161                 spin_unlock_bh(&sl->lock);
1162                 return 0;
1163
1164         case SIOCGOUTFILL:
1165                 if (put_user(sl->outfill, p))
1166                         return -EFAULT;
1167                 return 0;
1168         /* VSV changes end */
1169 #endif
1170         default:
1171                 return tty_mode_ioctl(tty, file, cmd, arg);
1172         }
1173 }
1174
1175 #ifdef CONFIG_COMPAT
1176 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
1177                                         unsigned int cmd, unsigned long arg)
1178 {
1179         switch (cmd) {
1180         case SIOCGIFNAME:
1181         case SIOCGIFENCAP:
1182         case SIOCSIFENCAP:
1183         case SIOCSIFHWADDR:
1184         case SIOCSKEEPALIVE:
1185         case SIOCGKEEPALIVE:
1186         case SIOCSOUTFILL:
1187         case SIOCGOUTFILL:
1188                 return slip_ioctl(tty, file, cmd,
1189                                   (unsigned long)compat_ptr(arg));
1190         }
1191
1192         return -ENOIOCTLCMD;
1193 }
1194 #endif
1195
1196 /* VSV changes start here */
1197 #ifdef CONFIG_SLIP_SMART
1198 /* function do_ioctl called from net/core/dev.c
1199    to allow get/set outfill/keepalive parameter
1200    by ifconfig                                 */
1201
1202 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
1203 {
1204         struct slip *sl = netdev_priv(dev);
1205         unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1206
1207         if (sl == NULL)         /* Allocation failed ?? */
1208                 return -ENODEV;
1209
1210         spin_lock_bh(&sl->lock);
1211
1212         if (!sl->tty) {
1213                 spin_unlock_bh(&sl->lock);
1214                 return -ENODEV;
1215         }
1216
1217         switch (cmd) {
1218         case SIOCSKEEPALIVE:
1219                 /* max for unchar */
1220                 if ((unsigned)*p > 255) {
1221                         spin_unlock_bh(&sl->lock);
1222                         return -EINVAL;
1223                 }
1224                 sl->keepalive = (u8)*p;
1225                 if (sl->keepalive != 0) {
1226                         sl->keepalive_timer.expires =
1227                                                 jiffies + sl->keepalive * HZ;
1228                         mod_timer(&sl->keepalive_timer,
1229                                                 jiffies + sl->keepalive * HZ);
1230                         set_bit(SLF_KEEPTEST, &sl->flags);
1231                 } else
1232                         del_timer(&sl->keepalive_timer);
1233                 break;
1234
1235         case SIOCGKEEPALIVE:
1236                 *p = sl->keepalive;
1237                 break;
1238
1239         case SIOCSOUTFILL:
1240                 if ((unsigned)*p > 255) { /* max for unchar */
1241                         spin_unlock_bh(&sl->lock);
1242                         return -EINVAL;
1243                 }
1244                 sl->outfill = (u8)*p;
1245                 if (sl->outfill != 0) {
1246                         mod_timer(&sl->outfill_timer,
1247                                                 jiffies + sl->outfill * HZ);
1248                         set_bit(SLF_OUTWAIT, &sl->flags);
1249                 } else
1250                         del_timer(&sl->outfill_timer);
1251                 break;
1252
1253         case SIOCGOUTFILL:
1254                 *p = sl->outfill;
1255                 break;
1256
1257         case SIOCSLEASE:
1258                 /* Resolve race condition, when ioctl'ing hanged up
1259                    and opened by another process device.
1260                  */
1261                 if (sl->tty != current->signal->tty &&
1262                                                 sl->pid != current->pid) {
1263                         spin_unlock_bh(&sl->lock);
1264                         return -EPERM;
1265                 }
1266                 sl->leased = 0;
1267                 if (*p)
1268                         sl->leased = 1;
1269                 break;
1270
1271         case SIOCGLEASE:
1272                 *p = sl->leased;
1273         }
1274         spin_unlock_bh(&sl->lock);
1275         return 0;
1276 }
1277 #endif
1278 /* VSV changes end */
1279
1280 static struct tty_ldisc_ops sl_ldisc = {
1281         .owner          = THIS_MODULE,
1282         .magic          = TTY_LDISC_MAGIC,
1283         .name           = "slip",
1284         .open           = slip_open,
1285         .close          = slip_close,
1286         .hangup         = slip_hangup,
1287         .ioctl          = slip_ioctl,
1288 #ifdef CONFIG_COMPAT
1289         .compat_ioctl   = slip_compat_ioctl,
1290 #endif
1291         .receive_buf    = slip_receive_buf,
1292         .write_wakeup   = slip_write_wakeup,
1293 };
1294
1295 static int __init slip_init(void)
1296 {
1297         int status;
1298
1299         if (slip_maxdev < 4)
1300                 slip_maxdev = 4; /* Sanity */
1301
1302         printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1303 #ifdef CONFIG_SLIP_MODE_SLIP6
1304                " (6 bit encapsulation enabled)"
1305 #endif
1306                ".\n",
1307                SLIP_VERSION, slip_maxdev);
1308 #if defined(SL_INCLUDE_CSLIP)
1309         printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1310 #endif
1311 #ifdef CONFIG_SLIP_SMART
1312         printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1313 #endif
1314
1315         slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev,
1316                                                                 GFP_KERNEL);
1317         if (!slip_devs)
1318                 return -ENOMEM;
1319
1320         /* Fill in our line protocol discipline, and register it */
1321         status = tty_register_ldisc(N_SLIP, &sl_ldisc);
1322         if (status != 0) {
1323                 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1324                 kfree(slip_devs);
1325         }
1326         return status;
1327 }
1328
1329 static void __exit slip_exit(void)
1330 {
1331         int i;
1332         struct net_device *dev;
1333         struct slip *sl;
1334         unsigned long timeout = jiffies + HZ;
1335         int busy = 0;
1336
1337         if (slip_devs == NULL)
1338                 return;
1339
1340         /* First of all: check for active disciplines and hangup them.
1341          */
1342         do {
1343                 if (busy)
1344                         msleep_interruptible(100);
1345
1346                 busy = 0;
1347                 for (i = 0; i < slip_maxdev; i++) {
1348                         dev = slip_devs[i];
1349                         if (!dev)
1350                                 continue;
1351                         sl = netdev_priv(dev);
1352                         spin_lock_bh(&sl->lock);
1353                         if (sl->tty) {
1354                                 busy++;
1355                                 tty_hangup(sl->tty);
1356                         }
1357                         spin_unlock_bh(&sl->lock);
1358                 }
1359         } while (busy && time_before(jiffies, timeout));
1360
1361         /* FIXME: hangup is async so we should wait when doing this second
1362            phase */
1363
1364         for (i = 0; i < slip_maxdev; i++) {
1365                 dev = slip_devs[i];
1366                 if (!dev)
1367                         continue;
1368                 slip_devs[i] = NULL;
1369
1370                 sl = netdev_priv(dev);
1371                 if (sl->tty) {
1372                         printk(KERN_ERR "%s: tty discipline still running\n",
1373                                dev->name);
1374                         /* Intentionally leak the control block. */
1375                         dev->destructor = NULL;
1376                 }
1377
1378                 unregister_netdev(dev);
1379         }
1380
1381         kfree(slip_devs);
1382         slip_devs = NULL;
1383
1384         i = tty_unregister_ldisc(N_SLIP);
1385         if (i != 0)
1386                 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1387 }
1388
1389 module_init(slip_init);
1390 module_exit(slip_exit);
1391
1392 #ifdef CONFIG_SLIP_SMART
1393 /*
1394  * This is start of the code for multislip style line checking
1395  * added by Stanislav Voronyi. All changes before marked VSV
1396  */
1397
1398 static void sl_outfill(unsigned long sls)
1399 {
1400         struct slip *sl = (struct slip *)sls;
1401
1402         spin_lock(&sl->lock);
1403
1404         if (sl->tty == NULL)
1405                 goto out;
1406
1407         if (sl->outfill) {
1408                 if (test_bit(SLF_OUTWAIT, &sl->flags)) {
1409                         /* no packets were transmitted, do outfill */
1410 #ifdef CONFIG_SLIP_MODE_SLIP6
1411                         unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1412 #else
1413                         unsigned char s = END;
1414 #endif
1415                         /* put END into tty queue. Is it right ??? */
1416                         if (!netif_queue_stopped(sl->dev)) {
1417                                 /* if device busy no outfill */
1418                                 sl->tty->ops->write(sl->tty, &s, 1);
1419                         }
1420                 } else
1421                         set_bit(SLF_OUTWAIT, &sl->flags);
1422
1423                 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1424         }
1425 out:
1426         spin_unlock(&sl->lock);
1427 }
1428
1429 static void sl_keepalive(unsigned long sls)
1430 {
1431         struct slip *sl = (struct slip *)sls;
1432
1433         spin_lock(&sl->lock);
1434
1435         if (sl->tty == NULL)
1436                 goto out;
1437
1438         if (sl->keepalive) {
1439                 if (test_bit(SLF_KEEPTEST, &sl->flags)) {
1440                         /* keepalive still high :(, we must hangup */
1441                         if (sl->outfill)
1442                                 /* outfill timer must be deleted too */
1443                                 (void)del_timer(&sl->outfill_timer);
1444                         printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1445                         /* this must hangup tty & close slip */
1446                         tty_hangup(sl->tty);
1447                         /* I think we need not something else */
1448                         goto out;
1449                 } else
1450                         set_bit(SLF_KEEPTEST, &sl->flags);
1451
1452                 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1453         }
1454 out:
1455         spin_unlock(&sl->lock);
1456 }
1457
1458 #endif
1459 MODULE_LICENSE("GPL");
1460 MODULE_ALIAS_LDISC(N_SLIP);