Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 844 insertions, 0 deletions

diff --git a/drivers/net/wan/x25_asy.c b/drivers/net/wan/x25_asy.c
new file mode 100644
index 000000000000..8c5cfcb55826
--- /dev/null
+++ b/drivers/net/wan/x25_asy.c
@@ -0,0 +1,844 @@
+/*
+ *      Things to sort out:
+ *
+ *      o       tbusy handling
+ *      o       allow users to set the parameters
+ *      o       sync/async switching ?
+ *
+ *      Note: This does _not_ implement CCITT X.25 asynchronous framing
+ *      recommendations. Its primarily for testing purposes. If you wanted
+ *      to do CCITT then in theory all you need is to nick the HDLC async
+ *      checksum routines from ppp.c
+ *      Changes:
+ *
+ *      2000-10-29      Henner Eisen    lapb_data_indication() return status.
+ */
+
+#include <linux/module.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <linux/bitops.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/if_arp.h>
+#include <linux/x25.h>
+#include <linux/lapb.h>
+#include <linux/init.h>
+#include "x25_asy.h"
+
+#include <net/x25device.h>
+
+static struct net_device **x25_asy_devs;
+static int x25_asy_maxdev = SL_NRUNIT;
+
+module_param(x25_asy_maxdev, int, 0);
+MODULE_LICENSE("GPL");
+
+static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
+static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
+static void x25_asy_setup(struct net_device *dev);
+
+/* Find a free X.25 channel, and link in this `tty' line. */
+static struct x25_asy *x25_asy_alloc(void)
+{
+        struct net_device *dev = NULL;
+        struct x25_asy *sl;
+        int i;
+
+        if (x25_asy_devs == NULL)
+                return NULL;    /* Master array missing ! */
+
+        for (i = 0; i < x25_asy_maxdev; i++) {
+                dev = x25_asy_devs[i];
+
+                /* Not allocated ? */
+                if (dev == NULL)
+                        break;
+
+                sl = dev->priv;
+                /* Not in use ? */
+                if (!test_and_set_bit(SLF_INUSE, &sl->flags))
+                        return sl;
+        }
+
+
+        /* Sorry, too many, all slots in use */
+        if (i >= x25_asy_maxdev)
+                return NULL;
+
+        /* If no channels are available, allocate one */
+        if (!dev) {
+                char name[IFNAMSIZ];
+                sprintf(name, "x25asy%d", i);
+
+                dev = alloc_netdev(sizeof(struct x25_asy),
+                                   name, x25_asy_setup);
+                if (!dev)
+                        return NULL;
+
+                /* Initialize channel control data */
+                sl = dev->priv;
+                dev->base_addr    = i;
+
+                /* register device so that it can be ifconfig'ed       */
+                if (register_netdev(dev) == 0) {
+                        /* (Re-)Set the INUSE bit.   Very Important! */
+                        set_bit(SLF_INUSE, &sl->flags);
+                        x25_asy_devs[i] = dev;
+                        return sl;
+                } else {
+                        printk("x25_asy_alloc() - register_netdev() failure.\n");
+                        free_netdev(dev);
+                }
+        }
+        return NULL;
+}
+
+
+/* Free an X.25 channel. */
+static void x25_asy_free(struct x25_asy *sl)
+{
+        /* Free all X.25 frame buffers. */
+        if (sl->rbuff)  {
+                kfree(sl->rbuff);
+        }
+        sl->rbuff = NULL;
+        if (sl->xbuff)  {
+                kfree(sl->xbuff);
+        }
+        sl->xbuff = NULL;
+
+        if (!test_and_clear_bit(SLF_INUSE, &sl->flags)) {
+                printk("%s: x25_asy_free for already free unit.\n", sl->dev->name);
+        }
+}
+
+static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
+{
+        struct x25_asy *sl = dev->priv;
+        unsigned char *xbuff, *rbuff;
+        int len = 2* newmtu;
+
+        xbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
+        rbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
+
+        if (xbuff == NULL || rbuff == NULL)  
+        {
+                printk("%s: unable to grow X.25 buffers, MTU change cancelled.\n",
+                       dev->name);
+                if (xbuff != NULL)  
+                        kfree(xbuff);
+                if (rbuff != NULL)  
+                        kfree(rbuff);
+                return -ENOMEM;
+        }
+
+        spin_lock_bh(&sl->lock);
+        xbuff    = xchg(&sl->xbuff, xbuff);
+        if (sl->xleft)  {
+                if (sl->xleft <= len)  {
+                        memcpy(sl->xbuff, sl->xhead, sl->xleft);
+                } else  {
+                        sl->xleft = 0;
+                        sl->stats.tx_dropped++;
+                }
+        }
+        sl->xhead = sl->xbuff;
+
+        rbuff    = xchg(&sl->rbuff, rbuff);
+        if (sl->rcount)  {
+                if (sl->rcount <= len) {
+                        memcpy(sl->rbuff, rbuff, sl->rcount);
+                } else  {
+                        sl->rcount = 0;
+                        sl->stats.rx_over_errors++;
+                        set_bit(SLF_ERROR, &sl->flags);
+                }
+        }
+
+        dev->mtu    = newmtu;
+        sl->buffsize = len;
+
+        spin_unlock_bh(&sl->lock);
+
+        if (xbuff != NULL) 
+                kfree(xbuff);
+        if (rbuff != NULL)
+                kfree(rbuff);
+        return 0;
+}
+
+
+/* Set the "sending" flag.  This must be atomic, hence the ASM. */
+
+static inline void x25_asy_lock(struct x25_asy *sl)
+{
+        netif_stop_queue(sl->dev);
+}
+
+
+/* Clear the "sending" flag.  This must be atomic, hence the ASM. */
+
+static inline void x25_asy_unlock(struct x25_asy *sl)
+{
+        netif_wake_queue(sl->dev);
+}
+
+/* Send one completely decapsulated IP datagram to the IP layer. */
+
+static void x25_asy_bump(struct x25_asy *sl)
+{
+        struct sk_buff *skb;
+        int count;
+        int err;
+
+        count = sl->rcount;
+        sl->stats.rx_bytes+=count;
+        
+        skb = dev_alloc_skb(count+1);
+        if (skb == NULL)  
+        {
+                printk("%s: memory squeeze, dropping packet.\n", sl->dev->name);
+                sl->stats.rx_dropped++;
+                return;
+        }
+        skb_push(skb,1);        /* LAPB internal control */
+        memcpy(skb_put(skb,count), sl->rbuff, count);
+        skb->protocol = x25_type_trans(skb, sl->dev);
+        if((err=lapb_data_received(skb->dev, skb))!=LAPB_OK)
+        {
+                kfree_skb(skb);
+                printk(KERN_DEBUG "x25_asy: data received err - %d\n",err);
+        }
+        else
+        {
+                netif_rx(skb);
+                sl->dev->last_rx = jiffies;
+                sl->stats.rx_packets++;
+        }
+}
+
+/* Encapsulate one IP datagram and stuff into a TTY queue. */
+static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
+{
+        unsigned char *p;
+        int actual, count, mtu = sl->dev->mtu;
+
+        if (len > mtu) 
+        {               /* Sigh, shouldn't occur BUT ... */
+                len = mtu;
+                printk ("%s: truncating oversized transmit packet!\n", sl->dev->name);
+                sl->stats.tx_dropped++;
+                x25_asy_unlock(sl);
+                return;
+        }
+
+        p = icp;
+        count = x25_asy_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 driver.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.
+         */
+        sl->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
+        actual = sl->tty->driver->write(sl->tty, sl->xbuff, count);
+        sl->xleft = count - actual;
+        sl->xhead = sl->xbuff + actual;
+        /* VSV */
+        clear_bit(SLF_OUTWAIT, &sl->flags);     /* reset outfill flag */
+}
+
+/*
+ * Called by the driver when there's room for more data.  If we have
+ * more packets to send, we send them here.
+ */
+static void x25_asy_write_wakeup(struct tty_struct *tty)
+{
+        int actual;
+        struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
+
+        /* First make sure we're connected. */
+        if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
+                return;
+
+        if (sl->xleft <= 0)  
+        {
+                /* Now serial buffer is almost free & we can start
+                 * transmission of another packet */
+                sl->stats.tx_packets++;
+                tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
+                x25_asy_unlock(sl);
+                return;
+        }
+
+        actual = tty->driver->write(tty, sl->xhead, sl->xleft);
+        sl->xleft -= actual;
+        sl->xhead += actual;
+}
+
+static void x25_asy_timeout(struct net_device *dev)
+{
+        struct x25_asy *sl = (struct x25_asy*)(dev->priv);
+
+        spin_lock(&sl->lock);
+        if (netif_queue_stopped(dev)) {
+                /* May be we must check transmitter timeout here ?
+                 *      14 Oct 1994 Dmitry Gorodchanin.
+                 */
+                printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
+                       (sl->tty->driver->chars_in_buffer(sl->tty) || sl->xleft) ?
+                       "bad line quality" : "driver error");
+                sl->xleft = 0;
+                sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
+                x25_asy_unlock(sl);
+        }
+        spin_unlock(&sl->lock);
+}
+
+/* Encapsulate an IP datagram and kick it into a TTY queue. */
+
+static int x25_asy_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+        struct x25_asy *sl = (struct x25_asy*)(dev->priv);
+        int err;
+
+        if (!netif_running(sl->dev)) {
+                printk("%s: xmit call when iface is down\n", dev->name);
+                kfree_skb(skb);
+                return 0;
+        }
+        
+        switch(skb->data[0])
+        {
+                case 0x00:break;
+                case 0x01: /* Connection request .. do nothing */
+                        if((err=lapb_connect_request(dev))!=LAPB_OK)
+                                printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
+                        kfree_skb(skb);
+                        return 0;
+                case 0x02: /* Disconnect request .. do nothing - hang up ?? */
+                        if((err=lapb_disconnect_request(dev))!=LAPB_OK)
+                                printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
+                default:
+                        kfree_skb(skb);
+                        return  0;
+        }
+        skb_pull(skb,1);        /* Remove control byte */
+        /*
+         * If we are busy already- too bad.  We ought to be able
+         * to queue things at this point, to allow for a little
+         * frame buffer.  Oh well...
+         * -----------------------------------------------------
+         * I hate queues in X.25 driver. May be it's efficient,
+         * but for me latency is more important. ;)
+         * So, no queues !
+         *        14 Oct 1994  Dmitry Gorodchanin.
+         */
+        
+        if((err=lapb_data_request(dev,skb))!=LAPB_OK)
+        {
+                printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
+                kfree_skb(skb);
+                return 0;
+        }
+        return 0;
+}
+
+
+/*
+ *      LAPB interface boilerplate
+ */
+
+/*
+ *      Called when I frame data arrives. We did the work above - throw it
+ *      at the net layer.
+ */
+  
+static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
+{
+        skb->dev->last_rx = jiffies;
+        return netif_rx(skb);
+}
+
+/*
+ *      Data has emerged from the LAPB protocol machine. We don't handle
+ *      busy cases too well. Its tricky to see how to do this nicely -
+ *      perhaps lapb should allow us to bounce this ?
+ */
+ 
+static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
+{
+        struct x25_asy *sl=dev->priv;
+        
+        spin_lock(&sl->lock);
+        if (netif_queue_stopped(sl->dev) || sl->tty == NULL)
+        {
+                spin_unlock(&sl->lock);
+                printk(KERN_ERR "x25_asy: tbusy drop\n");
+                kfree_skb(skb);
+                return;
+        }
+        /* We were not busy, so we are now... :-) */
+        if (skb != NULL) 
+        {
+                x25_asy_lock(sl);
+                sl->stats.tx_bytes+=skb->len;
+                x25_asy_encaps(sl, skb->data, skb->len);
+                dev_kfree_skb(skb);
+        }
+        spin_unlock(&sl->lock);
+}
+
+/*
+ *      LAPB connection establish/down information.
+ */
+ 
+static void x25_asy_connected(struct net_device *dev, int reason)
+{
+        struct x25_asy *sl = dev->priv;
+        struct sk_buff *skb;
+        unsigned char *ptr;
+
+        if ((skb = dev_alloc_skb(1)) == NULL) {
+                printk(KERN_ERR "lapbeth: out of memory\n");
+                return;
+        }
+
+        ptr  = skb_put(skb, 1);
+        *ptr = 0x01;
+
+        skb->protocol = x25_type_trans(skb, sl->dev);
+        netif_rx(skb);
+        sl->dev->last_rx = jiffies;
+}
+
+static void x25_asy_disconnected(struct net_device *dev, int reason)
+{
+        struct x25_asy *sl = dev->priv;
+        struct sk_buff *skb;
+        unsigned char *ptr;
+
+        if ((skb = dev_alloc_skb(1)) == NULL) {
+                printk(KERN_ERR "x25_asy: out of memory\n");
+                return;
+        }
+
+        ptr  = skb_put(skb, 1);
+        *ptr = 0x02;
+
+        skb->protocol = x25_type_trans(skb, sl->dev);
+        netif_rx(skb);
+        sl->dev->last_rx = jiffies;
+}
+
+static struct lapb_register_struct x25_asy_callbacks = {
+        .connect_confirmation = x25_asy_connected,
+        .connect_indication = x25_asy_connected,
+        .disconnect_confirmation = x25_asy_disconnected,
+        .disconnect_indication = x25_asy_disconnected,
+        .data_indication = x25_asy_data_indication,
+        .data_transmit = x25_asy_data_transmit,
+
+};
+
+
+/* Open the low-level part of the X.25 channel. Easy! */
+static int x25_asy_open(struct net_device *dev)
+{
+        struct x25_asy *sl = (struct x25_asy*)(dev->priv);
+        unsigned long len;
+        int err;
+
+        if (sl->tty == NULL)
+                return -ENODEV;
+
+        /*
+         * Allocate the X.25 frame buffers:
+         *
+         * rbuff        Receive buffer.
+         * xbuff        Transmit buffer.
+         */
+
+        len = dev->mtu * 2;
+
+        sl->rbuff = (unsigned char *) kmalloc(len + 4, GFP_KERNEL);
+        if (sl->rbuff == NULL)   {
+                goto norbuff;
+        }
+        sl->xbuff = (unsigned char *) kmalloc(len + 4, GFP_KERNEL);
+        if (sl->xbuff == NULL)   {
+                goto noxbuff;
+        }
+
+        sl->buffsize = len;
+        sl->rcount   = 0;
+        sl->xleft    = 0;
+        sl->flags   &= (1 << SLF_INUSE);      /* Clear ESCAPE & ERROR flags */
+
+        netif_start_queue(dev);
+                        
+        /*
+         *      Now attach LAPB
+         */
+        if((err=lapb_register(dev, &x25_asy_callbacks))==LAPB_OK)
+                return 0;
+
+        /* Cleanup */
+        kfree(sl->xbuff);
+noxbuff:
+        kfree(sl->rbuff);
+norbuff:
+        return -ENOMEM;
+}
+
+
+/* Close the low-level part of the X.25 channel. Easy! */
+static int x25_asy_close(struct net_device *dev)
+{
+        struct x25_asy *sl = (struct x25_asy*)(dev->priv);
+        int err;
+
+        spin_lock(&sl->lock);
+        if (sl->tty) 
+                sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
+
+        netif_stop_queue(dev);
+        sl->rcount = 0;
+        sl->xleft  = 0;
+        if((err=lapb_unregister(dev))!=LAPB_OK)
+                printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",err);
+        spin_unlock(&sl->lock);
+        return 0;
+}
+
+static int x25_asy_receive_room(struct tty_struct *tty)
+{
+        return 65536;  /* We can handle an infinite amount of data. :-) */
+}
+
+/*
+ * Handle the 'receiver data ready' interrupt.
+ * This function is called by the 'tty_io' module in the kernel when
+ * a block of X.25 data has been received, which can now be decapsulated
+ * and sent on to some IP layer for further processing.
+ */
+ 
+static void x25_asy_receive_buf(struct tty_struct *tty, const unsigned char *cp, char *fp, int count)
+{
+        struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
+
+        if (!sl || sl->magic != X25_ASY_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->stats.rx_errors++;
+                        }
+                        cp++;
+                        continue;
+                }
+                x25_asy_unesc(sl, *cp++);
+        }
+}
+
+/*
+ * Open the high-level part of the X.25 channel.
+ * This function is called by the TTY module when the
+ * X.25 line discipline is called for.  Because we are
+ * sure the tty line exists, we only have to link it to
+ * a free X.25 channel...
+ */
+
+static int x25_asy_open_tty(struct tty_struct *tty)
+{
+        struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
+        int err;
+
+        /* First make sure we're not already connected. */
+        if (sl && sl->magic == X25_ASY_MAGIC) {
+                return -EEXIST;
+        }
+
+        /* OK.  Find a free X.25 channel to use. */
+        if ((sl = x25_asy_alloc()) == NULL) {
+                return -ENFILE;
+        }
+
+        sl->tty = tty;
+        tty->disc_data = sl;
+        if (tty->driver->flush_buffer)  {
+                tty->driver->flush_buffer(tty);
+        }
+        if (tty->ldisc.flush_buffer)  {
+                tty->ldisc.flush_buffer(tty);
+        }
+
+        /* Restore default settings */
+        sl->dev->type = ARPHRD_X25;
+        
+        /* Perform the low-level X.25 async init */
+        if ((err = x25_asy_open(sl->dev)))
+                return err;
+
+        /* Done.  We have linked the TTY line to a channel. */
+        return sl->dev->base_addr;
+}
+
+
+/*
+ * Close down an X.25 channel.
+ * This means flushing out any pending queues, and then restoring the
+ * TTY line discipline to what it was before it got hooked to X.25
+ * (which usually is TTY again).
+ */
+static void x25_asy_close_tty(struct tty_struct *tty)
+{
+        struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
+
+        /* First make sure we're connected. */
+        if (!sl || sl->magic != X25_ASY_MAGIC)
+                return;
+
+        if (sl->dev->flags & IFF_UP)
+        {
+                (void) dev_close(sl->dev);
+        }
+
+        tty->disc_data = NULL;
+        sl->tty = NULL;
+        x25_asy_free(sl);
+}
+
+
+static struct net_device_stats *x25_asy_get_stats(struct net_device *dev)
+{
+        struct x25_asy *sl = (struct x25_asy*)(dev->priv);
+
+        return &sl->stats;
+}
+
+
+ /************************************************************************
+  *                     STANDARD X.25 ENCAPSULATION                      *
+  ************************************************************************/
+
+int x25_asy_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++ = X25_END;       /* Send 10111110 bit seq */
+
+        /*
+         * For each byte in the packet, send the appropriate
+         * character sequence, according to the X.25 protocol.
+         */
+
+        while (len-- > 0) 
+        {
+                switch(c = *s++) 
+                {
+                        case X25_END:
+                                *ptr++ = X25_ESC;
+                                *ptr++ = X25_ESCAPE(X25_END);
+                                break;
+                        case X25_ESC:
+                                *ptr++ = X25_ESC;
+                                *ptr++ = X25_ESCAPE(X25_ESC);
+                                break;
+                         default:
+                                *ptr++ = c;
+                                break;
+                }
+        }
+        *ptr++ = X25_END;
+        return (ptr - d);
+}
+
+static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
+{
+
+        switch(s) 
+        {
+                case X25_END:
+                        if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2))  
+                        {
+                                x25_asy_bump(sl);
+                        }
+                        clear_bit(SLF_ESCAPE, &sl->flags);
+                        sl->rcount = 0;
+                        return;
+
+                case X25_ESC:
+                        set_bit(SLF_ESCAPE, &sl->flags);
+                        return;
+                        
+                case X25_ESCAPE(X25_ESC):
+                case X25_ESCAPE(X25_END):
+                        if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
+                                s = X25_UNESCAPE(s);
+                        break;
+        }
+        if (!test_bit(SLF_ERROR, &sl->flags))  
+        {
+                if (sl->rcount < sl->buffsize)  
+                {
+                        sl->rbuff[sl->rcount++] = s;
+                        return;
+                }
+                sl->stats.rx_over_errors++;
+                set_bit(SLF_ERROR, &sl->flags);
+        }
+}
+
+
+/* Perform I/O control on an active X.25 channel. */
+static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
+                         unsigned int cmd,  unsigned long arg)
+{
+        struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
+
+        /* First make sure we're connected. */
+        if (!sl || sl->magic != X25_ASY_MAGIC)
+                return -EINVAL;
+
+        switch(cmd) {
+        case SIOCGIFNAME:
+                if (copy_to_user((void __user *)arg, sl->dev->name,
+                                        strlen(sl->dev->name) + 1))
+                        return -EFAULT;
+                return 0;
+        case SIOCSIFHWADDR:
+                return -EINVAL;
+        /* Allow stty to read, but not set, the serial port */
+        case TCGETS:
+        case TCGETA:
+                return n_tty_ioctl(tty, file, cmd, arg);
+        default:
+                return -ENOIOCTLCMD;
+        }
+}
+
+static int x25_asy_open_dev(struct net_device *dev)
+{
+        struct x25_asy *sl = (struct x25_asy*)(dev->priv);
+        if(sl->tty==NULL)
+                return -ENODEV;
+        return 0;
+}
+
+/* Initialise the X.25 driver.  Called by the device init code */
+static void x25_asy_setup(struct net_device *dev)
+{
+        struct x25_asy *sl = dev->priv;
+
+        sl->magic  = X25_ASY_MAGIC;
+        sl->dev    = dev;
+        spin_lock_init(&sl->lock);
+        set_bit(SLF_INUSE, &sl->flags);
+
+        /*
+         *      Finish setting up the DEVICE info. 
+         */
+         
+        dev->mtu                = SL_MTU;
+        dev->hard_start_xmit    = x25_asy_xmit;
+        dev->tx_timeout         = x25_asy_timeout;
+        dev->watchdog_timeo     = HZ*20;
+        dev->open               = x25_asy_open_dev;
+        dev->stop               = x25_asy_close;
+        dev->get_stats          = x25_asy_get_stats;
+        dev->change_mtu         = x25_asy_change_mtu;
+        dev->hard_header_len    = 0;
+        dev->addr_len           = 0;
+        dev->type               = ARPHRD_X25;
+        dev->tx_queue_len       = 10;
+
+        /* New-style flags. */
+        dev->flags              = IFF_NOARP;
+}
+
+static struct tty_ldisc x25_ldisc = {
+        .owner          = THIS_MODULE,
+        .magic          = TTY_LDISC_MAGIC,
+        .name           = "X.25",
+        .open           = x25_asy_open_tty,
+        .close          = x25_asy_close_tty,
+        .ioctl          = x25_asy_ioctl,
+        .receive_buf    = x25_asy_receive_buf,
+        .receive_room   = x25_asy_receive_room,
+        .write_wakeup   = x25_asy_write_wakeup,
+};
+
+static int __init init_x25_asy(void)
+{
+        if (x25_asy_maxdev < 4)
+                x25_asy_maxdev = 4; /* Sanity */
+
+        printk(KERN_INFO "X.25 async: version 0.00 ALPHA "
+                        "(dynamic channels, max=%d).\n", x25_asy_maxdev );
+
+        x25_asy_devs = kmalloc(sizeof(struct net_device *)*x25_asy_maxdev, 
+                               GFP_KERNEL);
+        if (!x25_asy_devs) {
+                printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] "
+                                "array! Uaargh! (-> No X.25 available)\n");
+                return -ENOMEM;
+        }
+        memset(x25_asy_devs, 0, sizeof(struct net_device *)*x25_asy_maxdev); 
+
+        return tty_register_ldisc(N_X25, &x25_ldisc);
+}
+
+
+static void __exit exit_x25_asy(void)
+{
+        struct net_device *dev;
+        int i;
+
+        for (i = 0; i < x25_asy_maxdev; i++) {
+                dev = x25_asy_devs[i];
+                if (dev) {
+                        struct x25_asy *sl = dev->priv;
+
+                        spin_lock_bh(&sl->lock);
+                        if (sl->tty) 
+                                tty_hangup(sl->tty);
+
+                        spin_unlock_bh(&sl->lock);
+                        /*
+                         * VSV = if dev->start==0, then device
+                         * unregistered while close proc.
+                         */
+                        unregister_netdev(dev);
+                        free_netdev(dev);
+                }
+        }
+
+        kfree(x25_asy_devs);
+        tty_register_ldisc(N_X25, NULL);
+}
+
+module_init(init_x25_asy);
+module_exit(exit_x25_asy);