slip: Move the SLIP drivers

Move the Serial Line Internet Protocol (SLIP) drivers into
drivers/net/slip/ and make the necessary Kconfig and Makefile
changes.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Alan Cox <alan@linux.intel.com>

1 files changed, 0 insertions, 1444 deletions

diff --git a/drivers/net/slip.c b/drivers/net/slip.c
deleted file mode 100644
index ba08341fb92c..000000000000
--- a/drivers/net/slip.c
+++ /dev/null
@@ -1,1444 +0,0 @@
-/*
- * slip.c	This module implements the SLIP protocol for kernel-based
- *		devices like TTY.  It interfaces between a raw TTY, and the
- *		kernel's INET protocol layers.
- *
- * Version:	@(#)slip.c	0.8.3	12/24/94
- *
- * Authors:	Laurence Culhane, <loz@holmes.demon.co.uk>
- *		Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
- *
- * Fixes:
- *		Alan Cox	: 	Sanity checks and avoid tx overruns.
- *					Has a new sl->mtu field.
- *		Alan Cox	: 	Found cause of overrun. ifconfig sl0
- *					mtu upwards. Driver now spots this
- *					and grows/shrinks its buffers(hack!).
- *					Memory leak if you run out of memory
- *					setting up a slip driver fixed.
- *		Matt Dillon	:	Printable slip (borrowed from NET2E)
- *	Pauline Middelink	:	Slip driver fixes.
- *		Alan Cox	:	Honours the old SL_COMPRESSED flag
- *		Alan Cox	:	KISS AX.25 and AXUI IP support
- *		Michael Riepe	:	Automatic CSLIP recognition added
- *		Charles Hedrick :	CSLIP header length problem fix.
- *		Alan Cox	:	Corrected non-IP cases of the above.
- *		Alan Cox	:	Now uses hardware type as per FvK.
- *		Alan Cox	:	Default to 192.168.0.0 (RFC 1597)
- *		A.N.Kuznetsov	:	dev_tint() recursion fix.
- *	Dmitry Gorodchanin	:	SLIP memory leaks
- *      Dmitry Gorodchanin      :       Code cleanup. Reduce tty driver
- *                                      buffering from 4096 to 256 bytes.
- *                                      Improving SLIP response time.
- *                                      CONFIG_SLIP_MODE_SLIP6.
- *                                      ifconfig sl? up & down now works
- *					correctly.
- *					Modularization.
- *              Alan Cox        :       Oops - fix AX.25 buffer lengths
- *      Dmitry Gorodchanin      :       Even more cleanups. Preserve CSLIP
- *                                      statistics. Include CSLIP code only
- *                                      if it really needed.
- *		Alan Cox	:	Free slhc buffers in the right place.
- *		Alan Cox	:	Allow for digipeated IP over AX.25
- *		Matti Aarnio	:	Dynamic SLIP devices, with ideas taken
- *					from Jim Freeman's <jfree@caldera.com>
- *					dynamic PPP devices.  We do NOT kfree()
- *					device entries, just reg./unreg. them
- *					as they are needed.  We kfree() them
- *					at module cleanup.
- *					With MODULE-loading ``insmod'', user
- *					can issue parameter:  slip_maxdev=1024
- *					(Or how much he/she wants.. Default
- *					is 256)
- *	Stanislav Voronyi	:	Slip line checking, with ideas taken
- *					from multislip BSDI driver which was
- *					written by Igor Chechik, RELCOM Corp.
- *					Only algorithms have been ported to
- *					Linux SLIP driver.
- *	Vitaly E. Lavrov	:	Sane behaviour on tty hangup.
- *	Alexey Kuznetsov	:	Cleanup interfaces to tty & netdevice
- *					modules.
- */
-
-#define SL_CHECK_TRANSMIT
-#include <linux/module.h>
-#include <linux/moduleparam.h>
-
-#include <asm/system.h>
-#include <asm/uaccess.h>
-#include <linux/bitops.h>
-#include <linux/sched.h>
-#include <linux/string.h>
-#include <linux/mm.h>
-#include <linux/interrupt.h>
-#include <linux/in.h>
-#include <linux/tty.h>
-#include <linux/errno.h>
-#include <linux/netdevice.h>
-#include <linux/etherdevice.h>
-#include <linux/skbuff.h>
-#include <linux/rtnetlink.h>
-#include <linux/if_arp.h>
-#include <linux/if_slip.h>
-#include <linux/compat.h>
-#include <linux/delay.h>
-#include <linux/init.h>
-#include <linux/slab.h>
-#include "slip.h"
-#ifdef CONFIG_INET
-#include <linux/ip.h>
-#include <linux/tcp.h>
-#include <net/slhc_vj.h>
-#endif
-
-#define SLIP_VERSION	"0.8.4-NET3.019-NEWTTY"
-
-static struct net_device **slip_devs;
-
-static int slip_maxdev = SL_NRUNIT;
-module_param(slip_maxdev, int, 0);
-MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
-
-static int slip_esc(unsigned char *p, unsigned char *d, int len);
-static void slip_unesc(struct slip *sl, unsigned char c);
-#ifdef CONFIG_SLIP_MODE_SLIP6
-static int slip_esc6(unsigned char *p, unsigned char *d, int len);
-static void slip_unesc6(struct slip *sl, unsigned char c);
-#endif
-#ifdef CONFIG_SLIP_SMART
-static void sl_keepalive(unsigned long sls);
-static void sl_outfill(unsigned long sls);
-static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
-#endif
-
-/********************************
-*  Buffer administration routines:
-*	sl_alloc_bufs()
-*	sl_free_bufs()
-*	sl_realloc_bufs()
-*
-* NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because
-*	sl_realloc_bufs provides strong atomicity and reallocation
-*	on actively running device.
-*********************************/
-
-/*
-   Allocate channel buffers.
- */
-
-static int sl_alloc_bufs(struct slip *sl, int mtu)
-{
-	int err = -ENOBUFS;
-	unsigned long len;
-	char *rbuff = NULL;
-	char *xbuff = NULL;
-#ifdef SL_INCLUDE_CSLIP
-	char *cbuff = NULL;
-	struct slcompress *slcomp = NULL;
-#endif
-
-	/*
-	 * Allocate the SLIP frame buffers:
-	 *
-	 * rbuff	Receive buffer.
-	 * xbuff	Transmit buffer.
-	 * cbuff        Temporary compression buffer.
-	 */
-	len = mtu * 2;
-
-	/*
-	 * allow for arrival of larger UDP packets, even if we say not to
-	 * also fixes a bug in which SunOS sends 512-byte packets even with
-	 * an MSS of 128
-	 */
-	if (len < 576 * 2)
-		len = 576 * 2;
-	rbuff = kmalloc(len + 4, GFP_KERNEL);
-	if (rbuff == NULL)
-		goto err_exit;
-	xbuff = kmalloc(len + 4, GFP_KERNEL);
-	if (xbuff == NULL)
-		goto err_exit;
-#ifdef SL_INCLUDE_CSLIP
-	cbuff = kmalloc(len + 4, GFP_KERNEL);
-	if (cbuff == NULL)
-		goto err_exit;
-	slcomp = slhc_init(16, 16);
-	if (slcomp == NULL)
-		goto err_exit;
-#endif
-	spin_lock_bh(&sl->lock);
-	if (sl->tty == NULL) {
-		spin_unlock_bh(&sl->lock);
-		err = -ENODEV;
-		goto err_exit;
-	}
-	sl->mtu	     = mtu;
-	sl->buffsize = len;
-	sl->rcount   = 0;
-	sl->xleft    = 0;
-	rbuff = xchg(&sl->rbuff, rbuff);
-	xbuff = xchg(&sl->xbuff, xbuff);
-#ifdef SL_INCLUDE_CSLIP
-	cbuff = xchg(&sl->cbuff, cbuff);
-	slcomp = xchg(&sl->slcomp, slcomp);
-#endif
-#ifdef CONFIG_SLIP_MODE_SLIP6
-	sl->xdata    = 0;
-	sl->xbits    = 0;
-#endif
-	spin_unlock_bh(&sl->lock);
-	err = 0;
-
-	/* Cleanup */
-err_exit:
-#ifdef SL_INCLUDE_CSLIP
-	kfree(cbuff);
-	slhc_free(slcomp);
-#endif
-	kfree(xbuff);
-	kfree(rbuff);
-	return err;
-}
-
-/* Free a SLIP channel buffers. */
-static void sl_free_bufs(struct slip *sl)
-{
-	/* Free all SLIP frame buffers. */
-	kfree(xchg(&sl->rbuff, NULL));
-	kfree(xchg(&sl->xbuff, NULL));
-#ifdef SL_INCLUDE_CSLIP
-	kfree(xchg(&sl->cbuff, NULL));
-	slhc_free(xchg(&sl->slcomp, NULL));
-#endif
-}
-
-/*
-   Reallocate slip channel buffers.
- */
-
-static int sl_realloc_bufs(struct slip *sl, int mtu)
-{
-	int err = 0;
-	struct net_device *dev = sl->dev;
-	unsigned char *xbuff, *rbuff;
-#ifdef SL_INCLUDE_CSLIP
-	unsigned char *cbuff;
-#endif
-	int len = mtu * 2;
-
-/*
- * allow for arrival of larger UDP packets, even if we say not to
- * also fixes a bug in which SunOS sends 512-byte packets even with
- * an MSS of 128
- */
-	if (len < 576 * 2)
-		len = 576 * 2;
-
-	xbuff = kmalloc(len + 4, GFP_ATOMIC);
-	rbuff = kmalloc(len + 4, GFP_ATOMIC);
-#ifdef SL_INCLUDE_CSLIP
-	cbuff = kmalloc(len + 4, GFP_ATOMIC);
-#endif
-
-
-#ifdef SL_INCLUDE_CSLIP
-	if (xbuff == NULL || rbuff == NULL || cbuff == NULL)  {
-#else
-	if (xbuff == NULL || rbuff == NULL)  {
-#endif
-		if (mtu > sl->mtu) {
-			printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n",
-			       dev->name);
-			err = -ENOBUFS;
-		}
-		goto done;
-	}
-	spin_lock_bh(&sl->lock);
-
-	err = -ENODEV;
-	if (sl->tty == NULL)
-		goto done_on_bh;
-
-	xbuff    = xchg(&sl->xbuff, xbuff);
-	rbuff    = xchg(&sl->rbuff, rbuff);
-#ifdef SL_INCLUDE_CSLIP
-	cbuff    = xchg(&sl->cbuff, cbuff);
-#endif
-	if (sl->xleft)  {
-		if (sl->xleft <= len)  {
-			memcpy(sl->xbuff, sl->xhead, sl->xleft);
-		} else  {
-			sl->xleft = 0;
-			dev->stats.tx_dropped++;
-		}
-	}
-	sl->xhead = sl->xbuff;
-
-	if (sl->rcount)  {
-		if (sl->rcount <= len) {
-			memcpy(sl->rbuff, rbuff, sl->rcount);
-		} else  {
-			sl->rcount = 0;
-			dev->stats.rx_over_errors++;
-			set_bit(SLF_ERROR, &sl->flags);
-		}
-	}
-	sl->mtu      = mtu;
-	dev->mtu      = mtu;
-	sl->buffsize = len;
-	err = 0;
-
-done_on_bh:
-	spin_unlock_bh(&sl->lock);
-
-done:
-	kfree(xbuff);
-	kfree(rbuff);
-#ifdef SL_INCLUDE_CSLIP
-	kfree(cbuff);
-#endif
-	return err;
-}
-
-
-/* Set the "sending" flag.  This must be atomic hence the set_bit. */
-static inline void sl_lock(struct slip *sl)
-{
-	netif_stop_queue(sl->dev);
-}
-
-
-/* Clear the "sending" flag.  This must be atomic, hence the ASM. */
-static inline void sl_unlock(struct slip *sl)
-{
-	netif_wake_queue(sl->dev);
-}
-
-/* Send one completely decapsulated IP datagram to the IP layer. */
-static void sl_bump(struct slip *sl)
-{
-	struct net_device *dev = sl->dev;
-	struct sk_buff *skb;
-	int count;
-
-	count = sl->rcount;
-#ifdef SL_INCLUDE_CSLIP
-	if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
-		unsigned char c = sl->rbuff[0];
-		if (c & SL_TYPE_COMPRESSED_TCP) {
-			/* ignore compressed packets when CSLIP is off */
-			if (!(sl->mode & SL_MODE_CSLIP)) {
-				printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name);
-				return;
-			}
-			/* make sure we've reserved enough space for uncompress
-			   to use */
-			if (count + 80 > sl->buffsize) {
-				dev->stats.rx_over_errors++;
-				return;
-			}
-			count = slhc_uncompress(sl->slcomp, sl->rbuff, count);
-			if (count <= 0)
-				return;
-		} else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {
-			if (!(sl->mode & SL_MODE_CSLIP)) {
-				/* turn on header compression */
-				sl->mode |= SL_MODE_CSLIP;
-				sl->mode &= ~SL_MODE_ADAPTIVE;
-				printk(KERN_INFO "%s: header compression turned on\n", dev->name);
-			}
-			sl->rbuff[0] &= 0x4f;
-			if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0)
-				return;
-		}
-	}
-#endif  /* SL_INCLUDE_CSLIP */
-
-	dev->stats.rx_bytes += count;
-
-	skb = dev_alloc_skb(count);
-	if (skb == NULL) {
-		printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name);
-		dev->stats.rx_dropped++;
-		return;
-	}
-	skb->dev = dev;
-	memcpy(skb_put(skb, count), sl->rbuff, count);
-	skb_reset_mac_header(skb);
-	skb->protocol = htons(ETH_P_IP);
-	netif_rx_ni(skb);
-	dev->stats.rx_packets++;
-}
-
-/* Encapsulate one IP datagram and stuff into a TTY queue. */
-static void sl_encaps(struct slip *sl, unsigned char *icp, int len)
-{
-	unsigned char *p;
-	int actual, count;
-
-	if (len > sl->mtu) {		/* Sigh, shouldn't occur BUT ... */
-		printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name);
-		sl->dev->stats.tx_dropped++;
-		sl_unlock(sl);
-		return;
-	}
-
-	p = icp;
-#ifdef SL_INCLUDE_CSLIP
-	if (sl->mode & SL_MODE_CSLIP)
-		len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);
-#endif
-#ifdef CONFIG_SLIP_MODE_SLIP6
-	if (sl->mode & SL_MODE_SLIP6)
-		count = slip_esc6(p, (unsigned char *) sl->xbuff, len);
-	else
-#endif
-		count = slip_esc(p, (unsigned char *) sl->xbuff, len);
-
-	/* Order of next two lines is *very* important.
-	 * When we are sending a little amount of data,
-	 * the transfer may be completed inside the ops->write()
-	 * routine, because it's running with interrupts enabled.
-	 * In this case we *never* got WRITE_WAKEUP event,
-	 * if we did not request it before write operation.
-	 *       14 Oct 1994  Dmitry Gorodchanin.
-	 */
-	set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
-	actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
-#ifdef SL_CHECK_TRANSMIT
-	sl->dev->trans_start = jiffies;
-#endif
-	sl->xleft = count - actual;
-	sl->xhead = sl->xbuff + actual;
-#ifdef CONFIG_SLIP_SMART
-	/* VSV */
-	clear_bit(SLF_OUTWAIT, &sl->flags);	/* reset outfill flag */
-#endif
-}
-
-/*
- * Called by the driver when there's room for more data.  If we have
- * more packets to send, we send them here.
- */
-static void slip_write_wakeup(struct tty_struct *tty)
-{
-	int actual;
-	struct slip *sl = tty->disc_data;
-
-	/* First make sure we're connected. */
-	if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
-		return;
-
-	if (sl->xleft <= 0)  {
-		/* Now serial buffer is almost free & we can start
-		 * transmission of another packet */
-		sl->dev->stats.tx_packets++;
-		clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
-		sl_unlock(sl);
-		return;
-	}
-
-	actual = tty->ops->write(tty, sl->xhead, sl->xleft);
-	sl->xleft -= actual;
-	sl->xhead += actual;
-}
-
-static void sl_tx_timeout(struct net_device *dev)
-{
-	struct slip *sl = netdev_priv(dev);
-
-	spin_lock(&sl->lock);
-
-	if (netif_queue_stopped(dev)) {
-		if (!netif_running(dev))
-			goto out;
-
-		/* May be we must check transmitter timeout here ?
-		 *      14 Oct 1994 Dmitry Gorodchanin.
-		 */
-#ifdef SL_CHECK_TRANSMIT
-		if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ))  {
-			/* 20 sec timeout not reached */
-			goto out;
-		}
-		printk(KERN_WARNING "%s: transmit timed out, %s?\n",
-			dev->name,
-			(tty_chars_in_buffer(sl->tty) || sl->xleft) ?
-				"bad line quality" : "driver error");
-		sl->xleft = 0;
-		clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
-		sl_unlock(sl);
-#endif
-	}
-out:
-	spin_unlock(&sl->lock);
-}
-
-
-/* Encapsulate an IP datagram and kick it into a TTY queue. */
-static netdev_tx_t
-sl_xmit(struct sk_buff *skb, struct net_device *dev)
-{
-	struct slip *sl = netdev_priv(dev);
-
-	spin_lock(&sl->lock);
-	if (!netif_running(dev)) {
-		spin_unlock(&sl->lock);
-		printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
-		dev_kfree_skb(skb);
-		return NETDEV_TX_OK;
-	}
-	if (sl->tty == NULL) {
-		spin_unlock(&sl->lock);
-		dev_kfree_skb(skb);
-		return NETDEV_TX_OK;
-	}
-
-	sl_lock(sl);
-	dev->stats.tx_bytes += skb->len;
-	sl_encaps(sl, skb->data, skb->len);
-	spin_unlock(&sl->lock);
-
-	dev_kfree_skb(skb);
-	return NETDEV_TX_OK;
-}
-
-
-/******************************************
- *   Routines looking at netdevice side.
- ******************************************/
-
-/* Netdevice UP -> DOWN routine */
-
-static int
-sl_close(struct net_device *dev)
-{
-	struct slip *sl = netdev_priv(dev);
-
-	spin_lock_bh(&sl->lock);
-	if (sl->tty)
-		/* TTY discipline is running. */
-		clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
-	netif_stop_queue(dev);
-	sl->rcount   = 0;
-	sl->xleft    = 0;
-	spin_unlock_bh(&sl->lock);
-
-	return 0;
-}
-
-/* Netdevice DOWN -> UP routine */
-
-static int sl_open(struct net_device *dev)
-{
-	struct slip *sl = netdev_priv(dev);
-
-	if (sl->tty == NULL)
-		return -ENODEV;
-
-	sl->flags &= (1 << SLF_INUSE);
-	netif_start_queue(dev);
-	return 0;
-}
-
-/* Netdevice change MTU request */
-
-static int sl_change_mtu(struct net_device *dev, int new_mtu)
-{
-	struct slip *sl = netdev_priv(dev);
-
-	if (new_mtu < 68 || new_mtu > 65534)
-		return -EINVAL;
-
-	if (new_mtu != dev->mtu)
-		return sl_realloc_bufs(sl, new_mtu);
-	return 0;
-}
-
-/* Netdevice get statistics request */
-
-static struct rtnl_link_stats64 *
-sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
-{
-	struct net_device_stats *devstats = &dev->stats;
-#ifdef SL_INCLUDE_CSLIP
-	struct slip *sl = netdev_priv(dev);
-	struct slcompress *comp = sl->slcomp;
-#endif
-	stats->rx_packets     = devstats->rx_packets;
-	stats->tx_packets     = devstats->tx_packets;
-	stats->rx_bytes       = devstats->rx_bytes;
-	stats->tx_bytes       = devstats->tx_bytes;
-	stats->rx_dropped     = devstats->rx_dropped;
-	stats->tx_dropped     = devstats->tx_dropped;
-	stats->tx_errors      = devstats->tx_errors;
-	stats->rx_errors      = devstats->rx_errors;
-	stats->rx_over_errors = devstats->rx_over_errors;
-
-#ifdef SL_INCLUDE_CSLIP
-	if (comp) {
-		/* Generic compressed statistics */
-		stats->rx_compressed   = comp->sls_i_compressed;
-		stats->tx_compressed   = comp->sls_o_compressed;
-
-		/* Are we really still needs this? */
-		stats->rx_fifo_errors += comp->sls_i_compressed;
-		stats->rx_dropped     += comp->sls_i_tossed;
-		stats->tx_fifo_errors += comp->sls_o_compressed;
-		stats->collisions     += comp->sls_o_misses;
-	}
-#endif
-	return stats;
-}
-
-/* Netdevice register callback */
-
-static int sl_init(struct net_device *dev)
-{
-	struct slip *sl = netdev_priv(dev);
-
-	/*
-	 *	Finish setting up the DEVICE info.
-	 */
-
-	dev->mtu		= sl->mtu;
-	dev->type		= ARPHRD_SLIP + sl->mode;
-#ifdef SL_CHECK_TRANSMIT
-	dev->watchdog_timeo	= 20*HZ;
-#endif
-	return 0;
-}
-
-
-static void sl_uninit(struct net_device *dev)
-{
-	struct slip *sl = netdev_priv(dev);
-
-	sl_free_bufs(sl);
-}
-
-/* Hook the destructor so we can free slip devices at the right point in time */
-static void sl_free_netdev(struct net_device *dev)
-{
-	int i = dev->base_addr;
-	free_netdev(dev);
-	slip_devs[i] = NULL;
-}
-
-static const struct net_device_ops sl_netdev_ops = {
-	.ndo_init		= sl_init,
-	.ndo_uninit	  	= sl_uninit,
-	.ndo_open		= sl_open,
-	.ndo_stop		= sl_close,
-	.ndo_start_xmit		= sl_xmit,
-	.ndo_get_stats64        = sl_get_stats64,
-	.ndo_change_mtu		= sl_change_mtu,
-	.ndo_tx_timeout		= sl_tx_timeout,
-#ifdef CONFIG_SLIP_SMART
-	.ndo_do_ioctl		= sl_ioctl,
-#endif
-};
-
-
-static void sl_setup(struct net_device *dev)
-{
-	dev->netdev_ops		= &sl_netdev_ops;
-	dev->destructor		= sl_free_netdev;
-
-	dev->hard_header_len	= 0;
-	dev->addr_len		= 0;
-	dev->tx_queue_len	= 10;
-
-	/* New-style flags. */
-	dev->flags		= IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
-}
-
-/******************************************
-  Routines looking at TTY side.
- ******************************************/
-
-
-/*
- * Handle the 'receiver data ready' interrupt.
- * This function is called by the 'tty_io' module in the kernel when
- * a block of SLIP data has been received, which can now be decapsulated
- * and sent on to some IP layer for further processing. This will not
- * be re-entered while running but other ldisc functions may be called
- * in parallel
- */
-
-static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
-							char *fp, int count)
-{
-	struct slip *sl = tty->disc_data;
-
-	if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
-		return;
-
-	/* Read the characters out of the buffer */
-	while (count--) {
-		if (fp && *fp++) {
-			if (!test_and_set_bit(SLF_ERROR, &sl->flags))
-				sl->dev->stats.rx_errors++;
-			cp++;
-			continue;
-		}
-#ifdef CONFIG_SLIP_MODE_SLIP6
-		if (sl->mode & SL_MODE_SLIP6)
-			slip_unesc6(sl, *cp++);
-		else
-#endif
-			slip_unesc(sl, *cp++);
-	}
-}
-
-/************************************
- *  slip_open helper routines.
- ************************************/
-
-/* Collect hanged up channels */
-static void sl_sync(void)
-{
-	int i;
-	struct net_device *dev;
-	struct slip	  *sl;
-
-	for (i = 0; i < slip_maxdev; i++) {
-		dev = slip_devs[i];
-		if (dev == NULL)
-			break;
-
-		sl = netdev_priv(dev);
-		if (sl->tty || sl->leased)
-			continue;
-		if (dev->flags & IFF_UP)
-			dev_close(dev);
-	}
-}
-
-
-/* Find a free SLIP channel, and link in this `tty' line. */
-static struct slip *sl_alloc(dev_t line)
-{
-	int i;
-	char name[IFNAMSIZ];
-	struct net_device *dev = NULL;
-	struct slip       *sl;
-
-	for (i = 0; i < slip_maxdev; i++) {
-		dev = slip_devs[i];
-		if (dev == NULL)
-			break;
-	}
-	/* Sorry, too many, all slots in use */
-	if (i >= slip_maxdev)
-		return NULL;
-
-	sprintf(name, "sl%d", i);
-	dev = alloc_netdev(sizeof(*sl), name, sl_setup);
-	if (!dev)
-		return NULL;
-
-	dev->base_addr  = i;
-	sl = netdev_priv(dev);
-
-	/* Initialize channel control data */
-	sl->magic       = SLIP_MAGIC;
-	sl->dev	      	= dev;
-	spin_lock_init(&sl->lock);
-	sl->mode        = SL_MODE_DEFAULT;
-#ifdef CONFIG_SLIP_SMART
-	/* initialize timer_list struct */
-	init_timer(&sl->keepalive_timer);
-	sl->keepalive_timer.data = (unsigned long)sl;
-	sl->keepalive_timer.function = sl_keepalive;
-	init_timer(&sl->outfill_timer);
-	sl->outfill_timer.data = (unsigned long)sl;
-	sl->outfill_timer.function = sl_outfill;
-#endif
-	slip_devs[i] = dev;
-	return sl;
-}
-
-/*
- * Open the high-level part of the SLIP channel.
- * This function is called by the TTY module when the
- * SLIP line discipline is called for.  Because we are
- * sure the tty line exists, we only have to link it to
- * a free SLIP channel...
- *
- * Called in process context serialized from other ldisc calls.
- */
-
-static int slip_open(struct tty_struct *tty)
-{
-	struct slip *sl;
-	int err;
-
-	if (!capable(CAP_NET_ADMIN))
-		return -EPERM;
-
-	if (tty->ops->write == NULL)
-		return -EOPNOTSUPP;
-
-	/* RTnetlink lock is misused here to serialize concurrent
-	   opens of slip channels. There are better ways, but it is
-	   the simplest one.
-	 */
-	rtnl_lock();
-
-	/* Collect hanged up channels. */
-	sl_sync();
-
-	sl = tty->disc_data;
-
-	err = -EEXIST;
-	/* First make sure we're not already connected. */
-	if (sl && sl->magic == SLIP_MAGIC)
-		goto err_exit;
-
-	/* OK.  Find a free SLIP channel to use. */
-	err = -ENFILE;
-	sl = sl_alloc(tty_devnum(tty));
-	if (sl == NULL)
-		goto err_exit;
-
-	sl->tty = tty;
-	tty->disc_data = sl;
-	sl->pid = current->pid;
-
-	if (!test_bit(SLF_INUSE, &sl->flags)) {
-		/* Perform the low-level SLIP initialization. */
-		err = sl_alloc_bufs(sl, SL_MTU);
-		if (err)
-			goto err_free_chan;
-
-		set_bit(SLF_INUSE, &sl->flags);
-
-		err = register_netdevice(sl->dev);
-		if (err)
-			goto err_free_bufs;
-	}
-
-#ifdef CONFIG_SLIP_SMART
-	if (sl->keepalive) {
-		sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;
-		add_timer(&sl->keepalive_timer);
-	}
-	if (sl->outfill) {
-		sl->outfill_timer.expires = jiffies + sl->outfill * HZ;
-		add_timer(&sl->outfill_timer);
-	}
-#endif
-
-	/* Done.  We have linked the TTY line to a channel. */
-	rtnl_unlock();
-	tty->receive_room = 65536;	/* We don't flow control */
-
-	/* TTY layer expects 0 on success */
-	return 0;
-
-err_free_bufs:
-	sl_free_bufs(sl);
-
-err_free_chan:
-	sl->tty = NULL;
-	tty->disc_data = NULL;
-	clear_bit(SLF_INUSE, &sl->flags);
-
-err_exit:
-	rtnl_unlock();
-
-	/* Count references from TTY module */
-	return err;
-}
-
-/*
- * Close down a SLIP channel.
- * This means flushing out any pending queues, and then returning. This
- * call is serialized against other ldisc functions.
- *
- * We also use this method fo a hangup event
- */
-
-static void slip_close(struct tty_struct *tty)
-{
-	struct slip *sl = tty->disc_data;
-
-	/* First make sure we're connected. */
-	if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
-		return;
-
-	tty->disc_data = NULL;
-	sl->tty = NULL;
-
-	/* VSV = very important to remove timers */
-#ifdef CONFIG_SLIP_SMART
-	del_timer_sync(&sl->keepalive_timer);
-	del_timer_sync(&sl->outfill_timer);
-#endif
-	/* Flush network side */
-	unregister_netdev(sl->dev);
-	/* This will complete via sl_free_netdev */
-}
-
-static int slip_hangup(struct tty_struct *tty)
-{
-	slip_close(tty);
-	return 0;
-}
- /************************************************************************
-  *			STANDARD SLIP ENCAPSULATION		  	 *
-  ************************************************************************/
-
-static int slip_esc(unsigned char *s, unsigned char *d, int len)
-{
-	unsigned char *ptr = d;
-	unsigned char c;
-
-	/*
-	 * Send an initial END character to flush out any
-	 * data that may have accumulated in the receiver
-	 * due to line noise.
-	 */
-
-	*ptr++ = END;
-
-	/*
-	 * For each byte in the packet, send the appropriate
-	 * character sequence, according to the SLIP protocol.
-	 */
-
-	while (len-- > 0) {
-		switch (c = *s++) {
-		case END:
-			*ptr++ = ESC;
-			*ptr++ = ESC_END;
-			break;
-		case ESC:
-			*ptr++ = ESC;
-			*ptr++ = ESC_ESC;
-			break;
-		default:
-			*ptr++ = c;
-			break;
-		}
-	}
-	*ptr++ = END;
-	return ptr - d;
-}
-
-static void slip_unesc(struct slip *sl, unsigned char s)
-{
-
-	switch (s) {
-	case END:
-#ifdef CONFIG_SLIP_SMART
-		/* drop keeptest bit = VSV */
-		if (test_bit(SLF_KEEPTEST, &sl->flags))
-			clear_bit(SLF_KEEPTEST, &sl->flags);
-#endif
-
-		if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
-		    (sl->rcount > 2))
-			sl_bump(sl);
-		clear_bit(SLF_ESCAPE, &sl->flags);
-		sl->rcount = 0;
-		return;
-
-	case ESC:
-		set_bit(SLF_ESCAPE, &sl->flags);
-		return;
-	case ESC_ESC:
-		if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
-			s = ESC;
-		break;
-	case ESC_END:
-		if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
-			s = END;
-		break;
-	}
-	if (!test_bit(SLF_ERROR, &sl->flags))  {
-		if (sl->rcount < sl->buffsize)  {
-			sl->rbuff[sl->rcount++] = s;
-			return;
-		}
-		sl->dev->stats.rx_over_errors++;
-		set_bit(SLF_ERROR, &sl->flags);
-	}
-}
-
-
-#ifdef CONFIG_SLIP_MODE_SLIP6
-/************************************************************************
- *			 6 BIT SLIP ENCAPSULATION			*
- ************************************************************************/
-
-static int slip_esc6(unsigned char *s, unsigned char *d, int len)
-{
-	unsigned char *ptr = d;
-	unsigned char c;
-	int i;
-	unsigned short v = 0;
-	short bits = 0;
-
-	/*
-	 * Send an initial END character to flush out any
-	 * data that may have accumulated in the receiver
-	 * due to line noise.
-	 */
-
-	*ptr++ = 0x70;
-
-	/*
-	 * Encode the packet into printable ascii characters
-	 */
-
-	for (i = 0; i < len; ++i) {
-		v = (v << 8) | s[i];
-		bits += 8;
-		while (bits >= 6) {
-			bits -= 6;
-			c = 0x30 + ((v >> bits) & 0x3F);
-			*ptr++ = c;
-		}
-	}
-	if (bits) {
-		c = 0x30 + ((v << (6 - bits)) & 0x3F);
-		*ptr++ = c;
-	}
-	*ptr++ = 0x70;
-	return ptr - d;
-}
-
-static void slip_unesc6(struct slip *sl, unsigned char s)
-{
-	unsigned char c;
-
-	if (s == 0x70) {
-#ifdef CONFIG_SLIP_SMART
-		/* drop keeptest bit = VSV */
-		if (test_bit(SLF_KEEPTEST, &sl->flags))
-			clear_bit(SLF_KEEPTEST, &sl->flags);
-#endif
-
-		if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
-		    (sl->rcount > 2))
-			sl_bump(sl);
-		sl->rcount = 0;
-		sl->xbits = 0;
-		sl->xdata = 0;
-	} else if (s >= 0x30 && s < 0x70) {
-		sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
-		sl->xbits += 6;
-		if (sl->xbits >= 8) {
-			sl->xbits -= 8;
-			c = (unsigned char)(sl->xdata >> sl->xbits);
-			if (!test_bit(SLF_ERROR, &sl->flags))  {
-				if (sl->rcount < sl->buffsize)  {
-					sl->rbuff[sl->rcount++] = c;
-					return;
-				}
-				sl->dev->stats.rx_over_errors++;
-				set_bit(SLF_ERROR, &sl->flags);
-			}
-		}
-	}
-}
-#endif /* CONFIG_SLIP_MODE_SLIP6 */
-
-/* Perform I/O control on an active SLIP channel. */
-static int slip_ioctl(struct tty_struct *tty, struct file *file,
-					unsigned int cmd, unsigned long arg)
-{
-	struct slip *sl = tty->disc_data;
-	unsigned int tmp;
-	int __user *p = (int __user *)arg;
-
-	/* First make sure we're connected. */
-	if (!sl || sl->magic != SLIP_MAGIC)
-		return -EINVAL;
-
-	switch (cmd) {
-	case SIOCGIFNAME:
-		tmp = strlen(sl->dev->name) + 1;
-		if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
-			return -EFAULT;
-		return 0;
-
-	case SIOCGIFENCAP:
-		if (put_user(sl->mode, p))
-			return -EFAULT;
-		return 0;
-
-	case SIOCSIFENCAP:
-		if (get_user(tmp, p))
-			return -EFAULT;
-#ifndef SL_INCLUDE_CSLIP
-		if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
-			return -EINVAL;
-#else
-		if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
-		    (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
-			/* return -EINVAL; */
-			tmp &= ~SL_MODE_ADAPTIVE;
-#endif
-#ifndef CONFIG_SLIP_MODE_SLIP6
-		if (tmp & SL_MODE_SLIP6)
-			return -EINVAL;
-#endif
-		sl->mode = tmp;
-		sl->dev->type = ARPHRD_SLIP + sl->mode;
-		return 0;
-
-	case SIOCSIFHWADDR:
-		return -EINVAL;
-
-#ifdef CONFIG_SLIP_SMART
-	/* VSV changes start here */
-	case SIOCSKEEPALIVE:
-		if (get_user(tmp, p))
-			return -EFAULT;
-		if (tmp > 255) /* max for unchar */
-			return -EINVAL;
-
-		spin_lock_bh(&sl->lock);
-		if (!sl->tty) {
-			spin_unlock_bh(&sl->lock);
-			return -ENODEV;
-		}
-		sl->keepalive = (u8)tmp;
-		if (sl->keepalive != 0) {
-			mod_timer(&sl->keepalive_timer,
-					jiffies + sl->keepalive * HZ);
-			set_bit(SLF_KEEPTEST, &sl->flags);
-		} else
-			del_timer(&sl->keepalive_timer);
-		spin_unlock_bh(&sl->lock);
-		return 0;
-
-	case SIOCGKEEPALIVE:
-		if (put_user(sl->keepalive, p))
-			return -EFAULT;
-		return 0;
-
-	case SIOCSOUTFILL:
-		if (get_user(tmp, p))
-			return -EFAULT;
-		if (tmp > 255) /* max for unchar */
-			return -EINVAL;
-		spin_lock_bh(&sl->lock);
-		if (!sl->tty) {
-			spin_unlock_bh(&sl->lock);
-			return -ENODEV;
-		}
-		sl->outfill = (u8)tmp;
-		if (sl->outfill != 0) {
-			mod_timer(&sl->outfill_timer,
-						jiffies + sl->outfill * HZ);
-			set_bit(SLF_OUTWAIT, &sl->flags);
-		} else
-			del_timer(&sl->outfill_timer);
-		spin_unlock_bh(&sl->lock);
-		return 0;
-
-	case SIOCGOUTFILL:
-		if (put_user(sl->outfill, p))
-			return -EFAULT;
-		return 0;
-	/* VSV changes end */
-#endif
-	default:
-		return tty_mode_ioctl(tty, file, cmd, arg);
-	}
-}
-
-#ifdef CONFIG_COMPAT
-static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
-					unsigned int cmd, unsigned long arg)
-{
-	switch (cmd) {
-	case SIOCGIFNAME:
-	case SIOCGIFENCAP:
-	case SIOCSIFENCAP:
-	case SIOCSIFHWADDR:
-	case SIOCSKEEPALIVE:
-	case SIOCGKEEPALIVE:
-	case SIOCSOUTFILL:
-	case SIOCGOUTFILL:
-		return slip_ioctl(tty, file, cmd,
-				  (unsigned long)compat_ptr(arg));
-	}
-
-	return -ENOIOCTLCMD;
-}
-#endif
-
-/* VSV changes start here */
-#ifdef CONFIG_SLIP_SMART
-/* function do_ioctl called from net/core/dev.c
-   to allow get/set outfill/keepalive parameter
-   by ifconfig                                 */
-
-static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
-{
-	struct slip *sl = netdev_priv(dev);
-	unsigned long *p = (unsigned long *)&rq->ifr_ifru;
-
-	if (sl == NULL)		/* Allocation failed ?? */
-		return -ENODEV;
-
-	spin_lock_bh(&sl->lock);
-
-	if (!sl->tty) {
-		spin_unlock_bh(&sl->lock);
-		return -ENODEV;
-	}
-
-	switch (cmd) {
-	case SIOCSKEEPALIVE:
-		/* max for unchar */
-		if ((unsigned)*p > 255) {
-			spin_unlock_bh(&sl->lock);
-			return -EINVAL;
-		}
-		sl->keepalive = (u8)*p;
-		if (sl->keepalive != 0) {
-			sl->keepalive_timer.expires =
-						jiffies + sl->keepalive * HZ;
-			mod_timer(&sl->keepalive_timer,
-						jiffies + sl->keepalive * HZ);
-			set_bit(SLF_KEEPTEST, &sl->flags);
-		} else
-			del_timer(&sl->keepalive_timer);
-		break;
-
-	case SIOCGKEEPALIVE:
-		*p = sl->keepalive;
-		break;
-
-	case SIOCSOUTFILL:
-		if ((unsigned)*p > 255) { /* max for unchar */
-			spin_unlock_bh(&sl->lock);
-			return -EINVAL;
-		}
-		sl->outfill = (u8)*p;
-		if (sl->outfill != 0) {
-			mod_timer(&sl->outfill_timer,
-						jiffies + sl->outfill * HZ);
-			set_bit(SLF_OUTWAIT, &sl->flags);
-		} else
-			del_timer(&sl->outfill_timer);
-		break;
-
-	case SIOCGOUTFILL:
-		*p = sl->outfill;
-		break;
-
-	case SIOCSLEASE:
-		/* Resolve race condition, when ioctl'ing hanged up
-		   and opened by another process device.
-		 */
-		if (sl->tty != current->signal->tty &&
-						sl->pid != current->pid) {
-			spin_unlock_bh(&sl->lock);
-			return -EPERM;
-		}
-		sl->leased = 0;
-		if (*p)
-			sl->leased = 1;
-		break;
-
-	case SIOCGLEASE:
-		*p = sl->leased;
-	}
-	spin_unlock_bh(&sl->lock);
-	return 0;
-}
-#endif
-/* VSV changes end */
-
-static struct tty_ldisc_ops sl_ldisc = {
-	.owner 		= THIS_MODULE,
-	.magic 		= TTY_LDISC_MAGIC,
-	.name 		= "slip",
-	.open 		= slip_open,
-	.close	 	= slip_close,
-	.hangup	 	= slip_hangup,
-	.ioctl		= slip_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl	= slip_compat_ioctl,
-#endif
-	.receive_buf	= slip_receive_buf,
-	.write_wakeup	= slip_write_wakeup,
-};
-
-static int __init slip_init(void)
-{
-	int status;
-
-	if (slip_maxdev < 4)
-		slip_maxdev = 4; /* Sanity */
-
-	printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
-#ifdef CONFIG_SLIP_MODE_SLIP6
-	       " (6 bit encapsulation enabled)"
-#endif
-	       ".\n",
-	       SLIP_VERSION, slip_maxdev);
-#if defined(SL_INCLUDE_CSLIP)
-	printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
-#endif
-#ifdef CONFIG_SLIP_SMART
-	printk(KERN_INFO "SLIP linefill/keepalive option.\n");
-#endif
-
-	slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev,
-								GFP_KERNEL);
-	if (!slip_devs) {
-		printk(KERN_ERR "SLIP: Can't allocate slip devices array.\n");
-		return -ENOMEM;
-	}
-
-	/* Fill in our line protocol discipline, and register it */
-	status = tty_register_ldisc(N_SLIP, &sl_ldisc);
-	if (status != 0) {
-		printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
-		kfree(slip_devs);
-	}
-	return status;
-}
-
-static void __exit slip_exit(void)
-{
-	int i;
-	struct net_device *dev;
-	struct slip *sl;
-	unsigned long timeout = jiffies + HZ;
-	int busy = 0;
-
-	if (slip_devs == NULL)
-		return;
-
-	/* First of all: check for active disciplines and hangup them.
-	 */
-	do {
-		if (busy)
-			msleep_interruptible(100);
-
-		busy = 0;
-		for (i = 0; i < slip_maxdev; i++) {
-			dev = slip_devs[i];
-			if (!dev)
-				continue;
-			sl = netdev_priv(dev);
-			spin_lock_bh(&sl->lock);
-			if (sl->tty) {
-				busy++;
-				tty_hangup(sl->tty);
-			}
-			spin_unlock_bh(&sl->lock);
-		}
-	} while (busy && time_before(jiffies, timeout));
-
-	/* FIXME: hangup is async so we should wait when doing this second
-	   phase */
-
-	for (i = 0; i < slip_maxdev; i++) {
-		dev = slip_devs[i];
-		if (!dev)
-			continue;
-		slip_devs[i] = NULL;
-
-		sl = netdev_priv(dev);
-		if (sl->tty) {
-			printk(KERN_ERR "%s: tty discipline still running\n",
-			       dev->name);
-			/* Intentionally leak the control block. */
-			dev->destructor = NULL;
-		}
-
-		unregister_netdev(dev);
-	}
-
-	kfree(slip_devs);
-	slip_devs = NULL;
-
-	i = tty_unregister_ldisc(N_SLIP);
-	if (i != 0)
-		printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
-}
-
-module_init(slip_init);
-module_exit(slip_exit);
-
-#ifdef CONFIG_SLIP_SMART
-/*
- * This is start of the code for multislip style line checking
- * added by Stanislav Voronyi. All changes before marked VSV
- */
-
-static void sl_outfill(unsigned long sls)
-{
-	struct slip *sl = (struct slip *)sls;
-
-	spin_lock(&sl->lock);
-
-	if (sl->tty == NULL)
-		goto out;
-
-	if (sl->outfill) {
-		if (test_bit(SLF_OUTWAIT, &sl->flags)) {
-			/* no packets were transmitted, do outfill */
-#ifdef CONFIG_SLIP_MODE_SLIP6
-			unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
-#else
-			unsigned char s = END;
-#endif
-			/* put END into tty queue. Is it right ??? */
-			if (!netif_queue_stopped(sl->dev)) {
-				/* if device busy no outfill */
-				sl->tty->ops->write(sl->tty, &s, 1);
-			}
-		} else
-			set_bit(SLF_OUTWAIT, &sl->flags);
-
-		mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
-	}
-out:
-	spin_unlock(&sl->lock);
-}
-
-static void sl_keepalive(unsigned long sls)
-{
-	struct slip *sl = (struct slip *)sls;
-
-	spin_lock(&sl->lock);
-
-	if (sl->tty == NULL)
-		goto out;
-
-	if (sl->keepalive) {
-		if (test_bit(SLF_KEEPTEST, &sl->flags)) {
-			/* keepalive still high :(, we must hangup */
-			if (sl->outfill)
-				/* outfill timer must be deleted too */
-				(void)del_timer(&sl->outfill_timer);
-			printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
-			/* this must hangup tty & close slip */
-			tty_hangup(sl->tty);
-			/* I think we need not something else */
-			goto out;
-		} else
-			set_bit(SLF_KEEPTEST, &sl->flags);
-
-		mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
-	}
-out:
-	spin_unlock(&sl->lock);
-}
-
-#endif
-MODULE_LICENSE("GPL");
-MODULE_ALIAS_LDISC(N_SLIP);