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 <linux/uaccess.h>
  68#include <linux/bitops.h>
  69#include <linux/sched/signal.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
  96static struct net_device **slip_devs;
  97
  98static int slip_maxdev = SL_NRUNIT;
  99module_param(slip_maxdev, int, 0);
 100MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
 101
 102static int slip_esc(unsigned char *p, unsigned char *d, int len);
 103static void slip_unesc(struct slip *sl, unsigned char c);
 104#ifdef CONFIG_SLIP_MODE_SLIP6
 105static int slip_esc6(unsigned char *p, unsigned char *d, int len);
 106static void slip_unesc6(struct slip *sl, unsigned char c);
 107#endif
 108#ifdef CONFIG_SLIP_SMART
 109static void sl_keepalive(struct timer_list *t);
 110static void sl_outfill(struct timer_list *t);
 111static 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
 129static 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 */
 194err_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. */
 205static 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
 220static 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
 292done_on_bh:
 293	spin_unlock_bh(&sl->lock);
 294
 295done:
 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. */
 306static 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. */
 313static 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. */
 319static 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	skb_put_data(skb, 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. */
 375static 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	netif_trans_update(sl->dev);
 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 */
 421static 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 */
 453static 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
 460static 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	}
 487out:
 488	spin_unlock(&sl->lock);
 489}
 490
 491
 492/* Encapsulate an IP datagram and kick it into a TTY queue. */
 493static netdev_tx_t
 494sl_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
 527static int
 528sl_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
 546static 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
 560static int sl_change_mtu(struct net_device *dev, int new_mtu)
 561{
 562	struct slip *sl = netdev_priv(dev);
 563
 564	return sl_realloc_bufs(sl, new_mtu);
 565}
 566
 567/* Netdevice get statistics request */
 568
 569static void
 570sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 571{
 572	struct net_device_stats *devstats = &dev->stats;
 573#ifdef SL_INCLUDE_CSLIP
 574	struct slip *sl = netdev_priv(dev);
 575	struct slcompress *comp = sl->slcomp;
 576#endif
 577	stats->rx_packets     = devstats->rx_packets;
 578	stats->tx_packets     = devstats->tx_packets;
 579	stats->rx_bytes       = devstats->rx_bytes;
 580	stats->tx_bytes       = devstats->tx_bytes;
 581	stats->rx_dropped     = devstats->rx_dropped;
 582	stats->tx_dropped     = devstats->tx_dropped;
 583	stats->tx_errors      = devstats->tx_errors;
 584	stats->rx_errors      = devstats->rx_errors;
 585	stats->rx_over_errors = devstats->rx_over_errors;
 586
 587#ifdef SL_INCLUDE_CSLIP
 588	if (comp) {
 589		/* Generic compressed statistics */
 590		stats->rx_compressed   = comp->sls_i_compressed;
 591		stats->tx_compressed   = comp->sls_o_compressed;
 592
 593		/* Are we really still needs this? */
 594		stats->rx_fifo_errors += comp->sls_i_compressed;
 595		stats->rx_dropped     += comp->sls_i_tossed;
 596		stats->tx_fifo_errors += comp->sls_o_compressed;
 597		stats->collisions     += comp->sls_o_misses;
 598	}
 599#endif
 600}
 601
 602/* Netdevice register callback */
 603
 604static int sl_init(struct net_device *dev)
 605{
 606	struct slip *sl = netdev_priv(dev);
 607
 608	/*
 609	 *	Finish setting up the DEVICE info.
 610	 */
 611
 612	dev->mtu		= sl->mtu;
 613	dev->type		= ARPHRD_SLIP + sl->mode;
 614#ifdef SL_CHECK_TRANSMIT
 615	dev->watchdog_timeo	= 20*HZ;
 616#endif
 617	return 0;
 618}
 619
 620
 621static void sl_uninit(struct net_device *dev)
 622{
 623	struct slip *sl = netdev_priv(dev);
 624
 625	sl_free_bufs(sl);
 626}
 627
 628/* Hook the destructor so we can free slip devices at the right point in time */
 629static void sl_free_netdev(struct net_device *dev)
 630{
 631	int i = dev->base_addr;
 632
 633	slip_devs[i] = NULL;
 634}
 635
 636static const struct net_device_ops sl_netdev_ops = {
 637	.ndo_init		= sl_init,
 638	.ndo_uninit	  	= sl_uninit,
 639	.ndo_open		= sl_open,
 640	.ndo_stop		= sl_close,
 641	.ndo_start_xmit		= sl_xmit,
 642	.ndo_get_stats64        = sl_get_stats64,
 643	.ndo_change_mtu		= sl_change_mtu,
 644	.ndo_tx_timeout		= sl_tx_timeout,
 645#ifdef CONFIG_SLIP_SMART
 646	.ndo_do_ioctl		= sl_ioctl,
 647#endif
 648};
 649
 650
 651static void sl_setup(struct net_device *dev)
 652{
 653	dev->netdev_ops		= &sl_netdev_ops;
 654	dev->needs_free_netdev	= true;
 655	dev->priv_destructor	= sl_free_netdev;
 656
 657	dev->hard_header_len	= 0;
 658	dev->addr_len		= 0;
 659	dev->tx_queue_len	= 10;
 660
 661	/* MTU range: 68 - 65534 */
 662	dev->min_mtu = 68;
 663	dev->max_mtu = 65534;
 664
 665	/* New-style flags. */
 666	dev->flags		= IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
 667}
 668
 669/******************************************
 670  Routines looking at TTY side.
 671 ******************************************/
 672
 673
 674/*
 675 * Handle the 'receiver data ready' interrupt.
 676 * This function is called by the 'tty_io' module in the kernel when
 677 * a block of SLIP data has been received, which can now be decapsulated
 678 * and sent on to some IP layer for further processing. This will not
 679 * be re-entered while running but other ldisc functions may be called
 680 * in parallel
 681 */
 682
 683static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 684							char *fp, int count)
 685{
 686	struct slip *sl = tty->disc_data;
 687
 688	if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
 689		return;
 690
 691	/* Read the characters out of the buffer */
 692	while (count--) {
 693		if (fp && *fp++) {
 694			if (!test_and_set_bit(SLF_ERROR, &sl->flags))
 695				sl->dev->stats.rx_errors++;
 696			cp++;
 697			continue;
 698		}
 699#ifdef CONFIG_SLIP_MODE_SLIP6
 700		if (sl->mode & SL_MODE_SLIP6)
 701			slip_unesc6(sl, *cp++);
 702		else
 703#endif
 704			slip_unesc(sl, *cp++);
 705	}
 706}
 707
 708/************************************
 709 *  slip_open helper routines.
 710 ************************************/
 711
 712/* Collect hanged up channels */
 713static void sl_sync(void)
 714{
 715	int i;
 716	struct net_device *dev;
 717	struct slip	  *sl;
 718
 719	for (i = 0; i < slip_maxdev; i++) {
 720		dev = slip_devs[i];
 721		if (dev == NULL)
 722			break;
 723
 724		sl = netdev_priv(dev);
 725		if (sl->tty || sl->leased)
 726			continue;
 727		if (dev->flags & IFF_UP)
 728			dev_close(dev);
 729	}
 730}
 731
 732
 733/* Find a free SLIP channel, and link in this `tty' line. */
 734static struct slip *sl_alloc(void)
 735{
 736	int i;
 737	char name[IFNAMSIZ];
 738	struct net_device *dev = NULL;
 739	struct slip       *sl;
 740
 741	for (i = 0; i < slip_maxdev; i++) {
 742		dev = slip_devs[i];
 743		if (dev == NULL)
 744			break;
 745	}
 746	/* Sorry, too many, all slots in use */
 747	if (i >= slip_maxdev)
 748		return NULL;
 749
 750	sprintf(name, "sl%d", i);
 751	dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup);
 752	if (!dev)
 753		return NULL;
 754
 755	dev->base_addr  = i;
 756	sl = netdev_priv(dev);
 757
 758	/* Initialize channel control data */
 759	sl->magic       = SLIP_MAGIC;
 760	sl->dev	      	= dev;
 761	spin_lock_init(&sl->lock);
 762	INIT_WORK(&sl->tx_work, slip_transmit);
 763	sl->mode        = SL_MODE_DEFAULT;
 764#ifdef CONFIG_SLIP_SMART
 765	/* initialize timer_list struct */
 766	timer_setup(&sl->keepalive_timer, sl_keepalive, 0);
 767	timer_setup(&sl->outfill_timer, sl_outfill, 0);
 768#endif
 769	slip_devs[i] = dev;
 770	return sl;
 771}
 772
 773/*
 774 * Open the high-level part of the SLIP channel.
 775 * This function is called by the TTY module when the
 776 * SLIP line discipline is called for.  Because we are
 777 * sure the tty line exists, we only have to link it to
 778 * a free SLIP channel...
 779 *
 780 * Called in process context serialized from other ldisc calls.
 781 */
 782
 783static int slip_open(struct tty_struct *tty)
 784{
 785	struct slip *sl;
 786	int err;
 787
 788	if (!capable(CAP_NET_ADMIN))
 789		return -EPERM;
 790
 791	if (tty->ops->write == NULL)
 792		return -EOPNOTSUPP;
 793
 794	/* RTnetlink lock is misused here to serialize concurrent
 795	   opens of slip channels. There are better ways, but it is
 796	   the simplest one.
 797	 */
 798	rtnl_lock();
 799
 800	/* Collect hanged up channels. */
 801	sl_sync();
 802
 803	sl = tty->disc_data;
 804
 805	err = -EEXIST;
 806	/* First make sure we're not already connected. */
 807	if (sl && sl->magic == SLIP_MAGIC)
 808		goto err_exit;
 809
 810	/* OK.  Find a free SLIP channel to use. */
 811	err = -ENFILE;
 812	sl = sl_alloc();
 813	if (sl == NULL)
 814		goto err_exit;
 815
 816	sl->tty = tty;
 817	tty->disc_data = sl;
 818	sl->pid = current->pid;
 819
 820	if (!test_bit(SLF_INUSE, &sl->flags)) {
 821		/* Perform the low-level SLIP initialization. */
 822		err = sl_alloc_bufs(sl, SL_MTU);
 823		if (err)
 824			goto err_free_chan;
 825
 826		set_bit(SLF_INUSE, &sl->flags);
 827
 828		err = register_netdevice(sl->dev);
 829		if (err)
 830			goto err_free_bufs;
 831	}
 832
 833#ifdef CONFIG_SLIP_SMART
 834	if (sl->keepalive) {
 835		sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;
 836		add_timer(&sl->keepalive_timer);
 837	}
 838	if (sl->outfill) {
 839		sl->outfill_timer.expires = jiffies + sl->outfill * HZ;
 840		add_timer(&sl->outfill_timer);
 841	}
 842#endif
 843
 844	/* Done.  We have linked the TTY line to a channel. */
 845	rtnl_unlock();
 846	tty->receive_room = 65536;	/* We don't flow control */
 847
 848	/* TTY layer expects 0 on success */
 849	return 0;
 850
 851err_free_bufs:
 852	sl_free_bufs(sl);
 853
 854err_free_chan:
 855	sl->tty = NULL;
 856	tty->disc_data = NULL;
 857	clear_bit(SLF_INUSE, &sl->flags);
 
 858
 859err_exit:
 860	rtnl_unlock();
 861
 862	/* Count references from TTY module */
 863	return err;
 864}
 865
 866/*
 867 * Close down a SLIP channel.
 868 * This means flushing out any pending queues, and then returning. This
 869 * call is serialized against other ldisc functions.
 870 *
 871 * We also use this method fo a hangup event
 872 */
 873
 874static void slip_close(struct tty_struct *tty)
 875{
 876	struct slip *sl = tty->disc_data;
 877
 878	/* First make sure we're connected. */
 879	if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
 880		return;
 881
 882	spin_lock_bh(&sl->lock);
 883	tty->disc_data = NULL;
 884	sl->tty = NULL;
 885	spin_unlock_bh(&sl->lock);
 886
 887	flush_work(&sl->tx_work);
 888
 889	/* VSV = very important to remove timers */
 890#ifdef CONFIG_SLIP_SMART
 891	del_timer_sync(&sl->keepalive_timer);
 892	del_timer_sync(&sl->outfill_timer);
 893#endif
 894	/* Flush network side */
 895	unregister_netdev(sl->dev);
 896	/* This will complete via sl_free_netdev */
 897}
 898
 899static int slip_hangup(struct tty_struct *tty)
 900{
 901	slip_close(tty);
 902	return 0;
 903}
 904 /************************************************************************
 905  *			STANDARD SLIP ENCAPSULATION		  	 *
 906  ************************************************************************/
 907
 908static int slip_esc(unsigned char *s, unsigned char *d, int len)
 909{
 910	unsigned char *ptr = d;
 911	unsigned char c;
 912
 913	/*
 914	 * Send an initial END character to flush out any
 915	 * data that may have accumulated in the receiver
 916	 * due to line noise.
 917	 */
 918
 919	*ptr++ = END;
 920
 921	/*
 922	 * For each byte in the packet, send the appropriate
 923	 * character sequence, according to the SLIP protocol.
 924	 */
 925
 926	while (len-- > 0) {
 927		switch (c = *s++) {
 928		case END:
 929			*ptr++ = ESC;
 930			*ptr++ = ESC_END;
 931			break;
 932		case ESC:
 933			*ptr++ = ESC;
 934			*ptr++ = ESC_ESC;
 935			break;
 936		default:
 937			*ptr++ = c;
 938			break;
 939		}
 940	}
 941	*ptr++ = END;
 942	return ptr - d;
 943}
 944
 945static void slip_unesc(struct slip *sl, unsigned char s)
 946{
 947
 948	switch (s) {
 949	case END:
 950#ifdef CONFIG_SLIP_SMART
 951		/* drop keeptest bit = VSV */
 952		if (test_bit(SLF_KEEPTEST, &sl->flags))
 953			clear_bit(SLF_KEEPTEST, &sl->flags);
 954#endif
 955
 956		if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
 957		    (sl->rcount > 2))
 958			sl_bump(sl);
 959		clear_bit(SLF_ESCAPE, &sl->flags);
 960		sl->rcount = 0;
 961		return;
 962
 963	case ESC:
 964		set_bit(SLF_ESCAPE, &sl->flags);
 965		return;
 966	case ESC_ESC:
 967		if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
 968			s = ESC;
 969		break;
 970	case ESC_END:
 971		if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
 972			s = END;
 973		break;
 974	}
 975	if (!test_bit(SLF_ERROR, &sl->flags))  {
 976		if (sl->rcount < sl->buffsize)  {
 977			sl->rbuff[sl->rcount++] = s;
 978			return;
 979		}
 980		sl->dev->stats.rx_over_errors++;
 981		set_bit(SLF_ERROR, &sl->flags);
 982	}
 983}
 984
 985
 986#ifdef CONFIG_SLIP_MODE_SLIP6
 987/************************************************************************
 988 *			 6 BIT SLIP ENCAPSULATION			*
 989 ************************************************************************/
 990
 991static int slip_esc6(unsigned char *s, unsigned char *d, int len)
 992{
 993	unsigned char *ptr = d;
 994	unsigned char c;
 995	int i;
 996	unsigned short v = 0;
 997	short bits = 0;
 998
 999	/*
1000	 * Send an initial END character to flush out any
1001	 * data that may have accumulated in the receiver
1002	 * due to line noise.
1003	 */
1004
1005	*ptr++ = 0x70;
1006
1007	/*
1008	 * Encode the packet into printable ascii characters
1009	 */
1010
1011	for (i = 0; i < len; ++i) {
1012		v = (v << 8) | s[i];
1013		bits += 8;
1014		while (bits >= 6) {
1015			bits -= 6;
1016			c = 0x30 + ((v >> bits) & 0x3F);
1017			*ptr++ = c;
1018		}
1019	}
1020	if (bits) {
1021		c = 0x30 + ((v << (6 - bits)) & 0x3F);
1022		*ptr++ = c;
1023	}
1024	*ptr++ = 0x70;
1025	return ptr - d;
1026}
1027
1028static void slip_unesc6(struct slip *sl, unsigned char s)
1029{
1030	unsigned char c;
1031
1032	if (s == 0x70) {
1033#ifdef CONFIG_SLIP_SMART
1034		/* drop keeptest bit = VSV */
1035		if (test_bit(SLF_KEEPTEST, &sl->flags))
1036			clear_bit(SLF_KEEPTEST, &sl->flags);
1037#endif
1038
1039		if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
1040		    (sl->rcount > 2))
1041			sl_bump(sl);
1042		sl->rcount = 0;
1043		sl->xbits = 0;
1044		sl->xdata = 0;
1045	} else if (s >= 0x30 && s < 0x70) {
1046		sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1047		sl->xbits += 6;
1048		if (sl->xbits >= 8) {
1049			sl->xbits -= 8;
1050			c = (unsigned char)(sl->xdata >> sl->xbits);
1051			if (!test_bit(SLF_ERROR, &sl->flags))  {
1052				if (sl->rcount < sl->buffsize)  {
1053					sl->rbuff[sl->rcount++] = c;
1054					return;
1055				}
1056				sl->dev->stats.rx_over_errors++;
1057				set_bit(SLF_ERROR, &sl->flags);
1058			}
1059		}
1060	}
1061}
1062#endif /* CONFIG_SLIP_MODE_SLIP6 */
1063
1064/* Perform I/O control on an active SLIP channel. */
1065static int slip_ioctl(struct tty_struct *tty, struct file *file,
1066					unsigned int cmd, unsigned long arg)
1067{
1068	struct slip *sl = tty->disc_data;
1069	unsigned int tmp;
1070	int __user *p = (int __user *)arg;
1071
1072	/* First make sure we're connected. */
1073	if (!sl || sl->magic != SLIP_MAGIC)
1074		return -EINVAL;
1075
1076	switch (cmd) {
1077	case SIOCGIFNAME:
1078		tmp = strlen(sl->dev->name) + 1;
1079		if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1080			return -EFAULT;
1081		return 0;
1082
1083	case SIOCGIFENCAP:
1084		if (put_user(sl->mode, p))
1085			return -EFAULT;
1086		return 0;
1087
1088	case SIOCSIFENCAP:
1089		if (get_user(tmp, p))
1090			return -EFAULT;
1091#ifndef SL_INCLUDE_CSLIP
1092		if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
1093			return -EINVAL;
1094#else
1095		if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1096		    (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
1097			/* return -EINVAL; */
1098			tmp &= ~SL_MODE_ADAPTIVE;
1099#endif
1100#ifndef CONFIG_SLIP_MODE_SLIP6
1101		if (tmp & SL_MODE_SLIP6)
1102			return -EINVAL;
1103#endif
1104		sl->mode = tmp;
1105		sl->dev->type = ARPHRD_SLIP + sl->mode;
1106		return 0;
1107
1108	case SIOCSIFHWADDR:
1109		return -EINVAL;
1110
1111#ifdef CONFIG_SLIP_SMART
1112	/* VSV changes start here */
1113	case SIOCSKEEPALIVE:
1114		if (get_user(tmp, p))
1115			return -EFAULT;
1116		if (tmp > 255) /* max for unchar */
1117			return -EINVAL;
1118
1119		spin_lock_bh(&sl->lock);
1120		if (!sl->tty) {
1121			spin_unlock_bh(&sl->lock);
1122			return -ENODEV;
1123		}
1124		sl->keepalive = (u8)tmp;
1125		if (sl->keepalive != 0) {
1126			mod_timer(&sl->keepalive_timer,
1127					jiffies + sl->keepalive * HZ);
1128			set_bit(SLF_KEEPTEST, &sl->flags);
1129		} else
1130			del_timer(&sl->keepalive_timer);
1131		spin_unlock_bh(&sl->lock);
1132		return 0;
1133
1134	case SIOCGKEEPALIVE:
1135		if (put_user(sl->keepalive, p))
1136			return -EFAULT;
1137		return 0;
1138
1139	case SIOCSOUTFILL:
1140		if (get_user(tmp, p))
1141			return -EFAULT;
1142		if (tmp > 255) /* max for unchar */
1143			return -EINVAL;
1144		spin_lock_bh(&sl->lock);
1145		if (!sl->tty) {
1146			spin_unlock_bh(&sl->lock);
1147			return -ENODEV;
1148		}
1149		sl->outfill = (u8)tmp;
1150		if (sl->outfill != 0) {
1151			mod_timer(&sl->outfill_timer,
1152						jiffies + sl->outfill * HZ);
1153			set_bit(SLF_OUTWAIT, &sl->flags);
1154		} else
1155			del_timer(&sl->outfill_timer);
1156		spin_unlock_bh(&sl->lock);
1157		return 0;
1158
1159	case SIOCGOUTFILL:
1160		if (put_user(sl->outfill, p))
1161			return -EFAULT;
1162		return 0;
1163	/* VSV changes end */
1164#endif
1165	default:
1166		return tty_mode_ioctl(tty, file, cmd, arg);
1167	}
1168}
1169
1170#ifdef CONFIG_COMPAT
1171static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
1172					unsigned int cmd, unsigned long arg)
1173{
1174	switch (cmd) {
1175	case SIOCGIFNAME:
1176	case SIOCGIFENCAP:
1177	case SIOCSIFENCAP:
1178	case SIOCSIFHWADDR:
1179	case SIOCSKEEPALIVE:
1180	case SIOCGKEEPALIVE:
1181	case SIOCSOUTFILL:
1182	case SIOCGOUTFILL:
1183		return slip_ioctl(tty, file, cmd,
1184				  (unsigned long)compat_ptr(arg));
1185	}
1186
1187	return -ENOIOCTLCMD;
1188}
1189#endif
1190
1191/* VSV changes start here */
1192#ifdef CONFIG_SLIP_SMART
1193/* function do_ioctl called from net/core/dev.c
1194   to allow get/set outfill/keepalive parameter
1195   by ifconfig                                 */
1196
1197static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
1198{
1199	struct slip *sl = netdev_priv(dev);
1200	unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1201
1202	if (sl == NULL)		/* Allocation failed ?? */
1203		return -ENODEV;
1204
1205	spin_lock_bh(&sl->lock);
1206
1207	if (!sl->tty) {
1208		spin_unlock_bh(&sl->lock);
1209		return -ENODEV;
1210	}
1211
1212	switch (cmd) {
1213	case SIOCSKEEPALIVE:
1214		/* max for unchar */
1215		if ((unsigned)*p > 255) {
1216			spin_unlock_bh(&sl->lock);
1217			return -EINVAL;
1218		}
1219		sl->keepalive = (u8)*p;
1220		if (sl->keepalive != 0) {
1221			sl->keepalive_timer.expires =
1222						jiffies + sl->keepalive * HZ;
1223			mod_timer(&sl->keepalive_timer,
1224						jiffies + sl->keepalive * HZ);
1225			set_bit(SLF_KEEPTEST, &sl->flags);
1226		} else
1227			del_timer(&sl->keepalive_timer);
1228		break;
1229
1230	case SIOCGKEEPALIVE:
1231		*p = sl->keepalive;
1232		break;
1233
1234	case SIOCSOUTFILL:
1235		if ((unsigned)*p > 255) { /* max for unchar */
1236			spin_unlock_bh(&sl->lock);
1237			return -EINVAL;
1238		}
1239		sl->outfill = (u8)*p;
1240		if (sl->outfill != 0) {
1241			mod_timer(&sl->outfill_timer,
1242						jiffies + sl->outfill * HZ);
1243			set_bit(SLF_OUTWAIT, &sl->flags);
1244		} else
1245			del_timer(&sl->outfill_timer);
1246		break;
1247
1248	case SIOCGOUTFILL:
1249		*p = sl->outfill;
1250		break;
1251
1252	case SIOCSLEASE:
1253		/* Resolve race condition, when ioctl'ing hanged up
1254		   and opened by another process device.
1255		 */
1256		if (sl->tty != current->signal->tty &&
1257						sl->pid != current->pid) {
1258			spin_unlock_bh(&sl->lock);
1259			return -EPERM;
1260		}
1261		sl->leased = 0;
1262		if (*p)
1263			sl->leased = 1;
1264		break;
1265
1266	case SIOCGLEASE:
1267		*p = sl->leased;
1268	}
1269	spin_unlock_bh(&sl->lock);
1270	return 0;
1271}
1272#endif
1273/* VSV changes end */
1274
1275static struct tty_ldisc_ops sl_ldisc = {
1276	.owner 		= THIS_MODULE,
1277	.magic 		= TTY_LDISC_MAGIC,
1278	.name 		= "slip",
1279	.open 		= slip_open,
1280	.close	 	= slip_close,
1281	.hangup	 	= slip_hangup,
1282	.ioctl		= slip_ioctl,
1283#ifdef CONFIG_COMPAT
1284	.compat_ioctl	= slip_compat_ioctl,
1285#endif
1286	.receive_buf	= slip_receive_buf,
1287	.write_wakeup	= slip_write_wakeup,
1288};
1289
1290static int __init slip_init(void)
1291{
1292	int status;
1293
1294	if (slip_maxdev < 4)
1295		slip_maxdev = 4; /* Sanity */
1296
1297	printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1298#ifdef CONFIG_SLIP_MODE_SLIP6
1299	       " (6 bit encapsulation enabled)"
1300#endif
1301	       ".\n",
1302	       SLIP_VERSION, slip_maxdev);
1303#if defined(SL_INCLUDE_CSLIP)
1304	printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1305#endif
1306#ifdef CONFIG_SLIP_SMART
1307	printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1308#endif
1309
1310	slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev,
1311								GFP_KERNEL);
1312	if (!slip_devs)
1313		return -ENOMEM;
1314
1315	/* Fill in our line protocol discipline, and register it */
1316	status = tty_register_ldisc(N_SLIP, &sl_ldisc);
1317	if (status != 0) {
1318		printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1319		kfree(slip_devs);
1320	}
1321	return status;
1322}
1323
1324static void __exit slip_exit(void)
1325{
1326	int i;
1327	struct net_device *dev;
1328	struct slip *sl;
1329	unsigned long timeout = jiffies + HZ;
1330	int busy = 0;
1331
1332	if (slip_devs == NULL)
1333		return;
1334
1335	/* First of all: check for active disciplines and hangup them.
1336	 */
1337	do {
1338		if (busy)
1339			msleep_interruptible(100);
1340
1341		busy = 0;
1342		for (i = 0; i < slip_maxdev; i++) {
1343			dev = slip_devs[i];
1344			if (!dev)
1345				continue;
1346			sl = netdev_priv(dev);
1347			spin_lock_bh(&sl->lock);
1348			if (sl->tty) {
1349				busy++;
1350				tty_hangup(sl->tty);
1351			}
1352			spin_unlock_bh(&sl->lock);
1353		}
1354	} while (busy && time_before(jiffies, timeout));
1355
1356	/* FIXME: hangup is async so we should wait when doing this second
1357	   phase */
1358
1359	for (i = 0; i < slip_maxdev; i++) {
1360		dev = slip_devs[i];
1361		if (!dev)
1362			continue;
1363		slip_devs[i] = NULL;
1364
1365		sl = netdev_priv(dev);
1366		if (sl->tty) {
1367			printk(KERN_ERR "%s: tty discipline still running\n",
1368			       dev->name);
1369		}
1370
1371		unregister_netdev(dev);
1372	}
1373
1374	kfree(slip_devs);
1375	slip_devs = NULL;
1376
1377	i = tty_unregister_ldisc(N_SLIP);
1378	if (i != 0)
1379		printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1380}
1381
1382module_init(slip_init);
1383module_exit(slip_exit);
1384
1385#ifdef CONFIG_SLIP_SMART
1386/*
1387 * This is start of the code for multislip style line checking
1388 * added by Stanislav Voronyi. All changes before marked VSV
1389 */
1390
1391static void sl_outfill(struct timer_list *t)
1392{
1393	struct slip *sl = from_timer(sl, t, outfill_timer);
1394
1395	spin_lock(&sl->lock);
1396
1397	if (sl->tty == NULL)
1398		goto out;
1399
1400	if (sl->outfill) {
1401		if (test_bit(SLF_OUTWAIT, &sl->flags)) {
1402			/* no packets were transmitted, do outfill */
1403#ifdef CONFIG_SLIP_MODE_SLIP6
1404			unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1405#else
1406			unsigned char s = END;
1407#endif
1408			/* put END into tty queue. Is it right ??? */
1409			if (!netif_queue_stopped(sl->dev)) {
1410				/* if device busy no outfill */
1411				sl->tty->ops->write(sl->tty, &s, 1);
1412			}
1413		} else
1414			set_bit(SLF_OUTWAIT, &sl->flags);
1415
1416		mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1417	}
1418out:
1419	spin_unlock(&sl->lock);
1420}
1421
1422static void sl_keepalive(struct timer_list *t)
1423{
1424	struct slip *sl = from_timer(sl, t, keepalive_timer);
1425
1426	spin_lock(&sl->lock);
1427
1428	if (sl->tty == NULL)
1429		goto out;
1430
1431	if (sl->keepalive) {
1432		if (test_bit(SLF_KEEPTEST, &sl->flags)) {
1433			/* keepalive still high :(, we must hangup */
1434			if (sl->outfill)
1435				/* outfill timer must be deleted too */
1436				(void)del_timer(&sl->outfill_timer);
1437			printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1438			/* this must hangup tty & close slip */
1439			tty_hangup(sl->tty);
1440			/* I think we need not something else */
1441			goto out;
1442		} else
1443			set_bit(SLF_KEEPTEST, &sl->flags);
1444
1445		mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1446	}
1447out:
1448	spin_unlock(&sl->lock);
1449}
1450
1451#endif
1452MODULE_LICENSE("GPL");
1453MODULE_ALIAS_LDISC(N_SLIP);