[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / net / wan / x25_asy.c

/*
 *	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. */
	kfree(sl->rbuff);
	sl->rbuff = NULL;
	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 = kmalloc(len + 4, GFP_ATOMIC);
	rbuff = kmalloc(len + 4, GFP_ATOMIC);

	if (xbuff == NULL || rbuff == NULL)  
	{
		printk("%s: unable to grow X.25 buffers, MTU change cancelled.\n",
		       dev->name);
		kfree(xbuff);
		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);

	kfree(xbuff);
	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 = kmalloc(len + 4, GFP_KERNEL);
	if (sl->rbuff == NULL)   {
		goto norbuff;
	}
	sl->xbuff = 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;
}

/*
 * 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;
	tty->receive_room = 65536;
	if (tty->driver->flush_buffer)  {
		tty->driver->flush_buffer(tty);
	}
	tty_ldisc_flush(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;
	default:
		return tty_mode_ioctl(tty, file, cmd, arg);
	}
}

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,
	.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 = kcalloc(x25_asy_maxdev, sizeof(struct net_device*), 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;
	}

	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_unregister_ldisc(N_X25);
}

module_init(init_x25_asy);
module_exit(exit_x25_asy);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Things to sort out:
	3	*
	4	* o tbusy handling
	5	* o allow users to set the parameters
	6	* o sync/async switching ?
	7	*
	8	* Note: This does _not_ implement CCITT X.25 asynchronous framing
	9	* recommendations. Its primarily for testing purposes. If you wanted
	10	* to do CCITT then in theory all you need is to nick the HDLC async
	11	* checksum routines from ppp.c
	12	* Changes:
	13	*
	14	* 2000-10-29 Henner Eisen lapb_data_indication() return status.
	15	*/
	16
	17	#include <linux/module.h>
	18
	19	#include <asm/system.h>
	20	#include <asm/uaccess.h>
	21	#include <linux/bitops.h>
	22	#include <linux/string.h>
	23	#include <linux/mm.h>
	24	#include <linux/interrupt.h>
	25	#include <linux/in.h>
	26	#include <linux/tty.h>
	27	#include <linux/errno.h>
	28	#include <linux/netdevice.h>
	29	#include <linux/etherdevice.h>
	30	#include <linux/skbuff.h>
	31	#include <linux/if_arp.h>
	32	#include <linux/x25.h>
	33	#include <linux/lapb.h>
	34	#include <linux/init.h>
	35	#include "x25_asy.h"
	36
	37	#include <net/x25device.h>
	38
	39	static struct net_device **x25_asy_devs;
	40	static int x25_asy_maxdev = SL_NRUNIT;
	41
	42	module_param(x25_asy_maxdev, int, 0);
	43	MODULE_LICENSE("GPL");
	44
	45	static int x25_asy_esc(unsigned char p, unsigned char d, int len);
	46	static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
	47	static void x25_asy_setup(struct net_device *dev);
	48
	49	/* Find a free X.25 channel, and link in this `tty' line. */
	50	static struct x25_asy *x25_asy_alloc(void)
	51	{
	52	struct net_device *dev = NULL;
	53	struct x25_asy *sl;
	54	int i;
	55
	56	if (x25_asy_devs == NULL)
	57	return NULL; /* Master array missing ! */
	58
	59	for (i = 0; i < x25_asy_maxdev; i++) {
	60	dev = x25_asy_devs[i];
	61
	62	/* Not allocated ? */
	63	if (dev == NULL)
	64	break;
65
66	sl = dev->priv;
67	/* Not in use ? */
68	if (!test_and_set_bit(SLF_INUSE, &sl->flags))
69	return sl;
70	}
71
72
73	/* Sorry, too many, all slots in use */
74	if (i >= x25_asy_maxdev)
75	return NULL;
76
77	/* If no channels are available, allocate one */
78	if (!dev) {
79	char name[IFNAMSIZ];
80	sprintf(name, "x25asy%d", i);
81
82	dev = alloc_netdev(sizeof(struct x25_asy),
83	name, x25_asy_setup);
84	if (!dev)
85	return NULL;
86
87	/* Initialize channel control data */
88	sl = dev->priv;
89	dev->base_addr = i;
90
91	/* register device so that it can be ifconfig'ed */
92	if (register_netdev(dev) == 0) {
93	/* (Re-)Set the INUSE bit. Very Important! */
94	set_bit(SLF_INUSE, &sl->flags);
95	x25_asy_devs[i] = dev;
96	return sl;
97	} else {
98	printk("x25_asy_alloc() - register_netdev() failure.\n");
99	free_netdev(dev);
100	}
101	}
102	return NULL;
103	}
104
105
106	/* Free an X.25 channel. */
107	static void x25_asy_free(struct x25_asy *sl)
108	{
109	/* Free all X.25 frame buffers. */
6a5d3621	110	kfree(sl->rbuff);
1da177e4	111	sl->rbuff = NULL;
6a5d3621	112	kfree(sl->xbuff);
1da177e4 LT	113	sl->xbuff = NULL;
	114
	115	if (!test_and_clear_bit(SLF_INUSE, &sl->flags)) {
	116	printk("%s: x25_asy_free for already free unit.\n", sl->dev->name);
	117	}
	118	}
	119
	120	static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
	121	{
	122	struct x25_asy *sl = dev->priv;
	123	unsigned char xbuff, rbuff;
	124	int len = 2* newmtu;
	125
5cbded58 RD	126	xbuff = kmalloc(len + 4, GFP_ATOMIC);
5cbded58 RD	127	rbuff = kmalloc(len + 4, GFP_ATOMIC);
1da177e4 LT	128
	129	if (xbuff == NULL \|\| rbuff == NULL)
	130	{
	131	printk("%s: unable to grow X.25 buffers, MTU change cancelled.\n",
	132	dev->name);
6a5d3621 JJ	133	kfree(xbuff);
6a5d3621 JJ	134	kfree(rbuff);
1da177e4 LT	135	return -ENOMEM;
	136	}
	137
	138	spin_lock_bh(&sl->lock);
	139	xbuff = xchg(&sl->xbuff, xbuff);
	140	if (sl->xleft) {
	141	if (sl->xleft <= len) {
	142	memcpy(sl->xbuff, sl->xhead, sl->xleft);
	143	} else {
	144	sl->xleft = 0;
	145	sl->stats.tx_dropped++;
	146	}
	147	}
	148	sl->xhead = sl->xbuff;
	149
	150	rbuff = xchg(&sl->rbuff, rbuff);
	151	if (sl->rcount) {
	152	if (sl->rcount <= len) {
	153	memcpy(sl->rbuff, rbuff, sl->rcount);
	154	} else {
	155	sl->rcount = 0;
	156	sl->stats.rx_over_errors++;
	157	set_bit(SLF_ERROR, &sl->flags);
	158	}
	159	}
	160
	161	dev->mtu = newmtu;
	162	sl->buffsize = len;
	163
	164	spin_unlock_bh(&sl->lock);
	165
6a5d3621 JJ	166	kfree(xbuff);
6a5d3621 JJ	167	kfree(rbuff);
1da177e4 LT	168	return 0;
	169	}
	170
	171
	172	/* Set the "sending" flag. This must be atomic, hence the ASM. */
	173
	174	static inline void x25_asy_lock(struct x25_asy *sl)
	175	{
	176	netif_stop_queue(sl->dev);
	177	}
	178
	179
	180	/* Clear the "sending" flag. This must be atomic, hence the ASM. */
	181
	182	static inline void x25_asy_unlock(struct x25_asy *sl)
	183	{
	184	netif_wake_queue(sl->dev);
	185	}
	186
	187	/* Send one completely decapsulated IP datagram to the IP layer. */
	188
	189	static void x25_asy_bump(struct x25_asy *sl)
	190	{
	191	struct sk_buff *skb;
	192	int count;
	193	int err;
	194
	195	count = sl->rcount;
	196	sl->stats.rx_bytes+=count;
	197
	198	skb = dev_alloc_skb(count+1);
	199	if (skb == NULL)
	200	{
	201	printk("%s: memory squeeze, dropping packet.\n", sl->dev->name);
	202	sl->stats.rx_dropped++;
	203	return;
	204	}
	205	skb_push(skb,1); /* LAPB internal control */
	206	memcpy(skb_put(skb,count), sl->rbuff, count);
	207	skb->protocol = x25_type_trans(skb, sl->dev);
	208	if((err=lapb_data_received(skb->dev, skb))!=LAPB_OK)
	209	{
	210	kfree_skb(skb);
	211	printk(KERN_DEBUG "x25_asy: data received err - %d\n",err);
	212	}
	213	else
	214	{
	215	netif_rx(skb);
	216	sl->dev->last_rx = jiffies;
	217	sl->stats.rx_packets++;
	218	}
	219	}
	220
	221	/* Encapsulate one IP datagram and stuff into a TTY queue. */
	222	static void x25_asy_encaps(struct x25_asy sl, unsigned char icp, int len)
	223	{
	224	unsigned char *p;
	225	int actual, count, mtu = sl->dev->mtu;
	226
	227	if (len > mtu)
	228	{ /* Sigh, shouldn't occur BUT ... */
	229	len = mtu;
	230	printk ("%s: truncating oversized transmit packet!\n", sl->dev->name);
	231	sl->stats.tx_dropped++;
232	x25_asy_unlock(sl);
233	return;
234	}
235
236	p = icp;
237	count = x25_asy_esc(p, (unsigned char *) sl->xbuff, len);
238
239	/* Order of next two lines is very important.
240	* When we are sending a little amount of data,
241	* the transfer may be completed inside driver.write()
242	* routine, because it's running with interrupts enabled.
243	* In this case we never got WRITE_WAKEUP event,
244	* if we did not request it before write operation.
245	* 14 Oct 1994 Dmitry Gorodchanin.
246	*/
247	sl->tty->flags \|= (1 << TTY_DO_WRITE_WAKEUP);
248	actual = sl->tty->driver->write(sl->tty, sl->xbuff, count);
249	sl->xleft = count - actual;
250	sl->xhead = sl->xbuff + actual;
251	/* VSV */
252	clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
253	}
254
255	/*
256	* Called by the driver when there's room for more data. If we have
257	* more packets to send, we send them here.
258	*/
259	static void x25_asy_write_wakeup(struct tty_struct *tty)
260	{
261	int actual;
262	struct x25_asy sl = (struct x25_asy ) tty->disc_data;
263
264	/* First make sure we're connected. */
265	if (!sl \|\| sl->magic != X25_ASY_MAGIC \|\| !netif_running(sl->dev))
266	return;
267
268	if (sl->xleft <= 0)
269	{
270	/* Now serial buffer is almost free & we can start
271	* transmission of another packet */
272	sl->stats.tx_packets++;
273	tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
274	x25_asy_unlock(sl);
275	return;
276	}
277
278	actual = tty->driver->write(tty, sl->xhead, sl->xleft);
279	sl->xleft -= actual;
280	sl->xhead += actual;
281	}
282
283	static void x25_asy_timeout(struct net_device *dev)
284	{
285	struct x25_asy sl = (struct x25_asy)(dev->priv);
286
287	spin_lock(&sl->lock);
288	if (netif_queue_stopped(dev)) {
289	/* May be we must check transmitter timeout here ?
290	* 14 Oct 1994 Dmitry Gorodchanin.
291	*/
292	printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
293	(sl->tty->driver->chars_in_buffer(sl->tty) \|\| sl->xleft) ?
294	"bad line quality" : "driver error");
295	sl->xleft = 0;
296	sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
297	x25_asy_unlock(sl);
298	}
299	spin_unlock(&sl->lock);
300	}
301
302	/* Encapsulate an IP datagram and kick it into a TTY queue. */
303
304	static int x25_asy_xmit(struct sk_buff skb, struct net_device dev)
305	{
306	struct x25_asy sl = (struct x25_asy)(dev->priv);
307	int err;
308
309	if (!netif_running(sl->dev)) {
310	printk("%s: xmit call when iface is down\n", dev->name);
311	kfree_skb(skb);
312	return 0;
313	}
314
315	switch(skb->data[0])
316	{
317	case 0x00:break;
318	case 0x01: /* Connection request .. do nothing */
319	if((err=lapb_connect_request(dev))!=LAPB_OK)
320	printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
321	kfree_skb(skb);
322	return 0;
323	case 0x02: /* Disconnect request .. do nothing - hang up ?? */
324	if((err=lapb_disconnect_request(dev))!=LAPB_OK)
325	printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
326	default:
327	kfree_skb(skb);
328	return 0;
329	}
330	skb_pull(skb,1); /* Remove control byte */
331	/*
332	* If we are busy already- too bad. We ought to be able
333	* to queue things at this point, to allow for a little
334	* frame buffer. Oh well...
335	* -----------------------------------------------------
336	* I hate queues in X.25 driver. May be it's efficient,
337	* but for me latency is more important. ;)
338	* So, no queues !
339	* 14 Oct 1994 Dmitry Gorodchanin.
340	*/
341
342	if((err=lapb_data_request(dev,skb))!=LAPB_OK)
343	{
344	printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
345	kfree_skb(skb);
346	return 0;
347	}
348	return 0;
349	}
350
351
352	/*
353	* LAPB interface boilerplate
354	*/
355
356	/*
357	* Called when I frame data arrives. We did the work above - throw it
358	* at the net layer.
359	*/
360
361	static int x25_asy_data_indication(struct net_device dev, struct sk_buff skb)
362	{
363	skb->dev->last_rx = jiffies;
364	return netif_rx(skb);
365	}
366
367	/*
368	* Data has emerged from the LAPB protocol machine. We don't handle
369	* busy cases too well. Its tricky to see how to do this nicely -
370	* perhaps lapb should allow us to bounce this ?
371	*/
372
373	static void x25_asy_data_transmit(struct net_device dev, struct sk_buff skb)
374	{
375	struct x25_asy *sl=dev->priv;
376
377	spin_lock(&sl->lock);
378	if (netif_queue_stopped(sl->dev) \|\| sl->tty == NULL)
379	{
380	spin_unlock(&sl->lock);
381	printk(KERN_ERR "x25_asy: tbusy drop\n");
382	kfree_skb(skb);
383	return;
384	}
385	/* We were not busy, so we are now... :-) */
386	if (skb != NULL)
387	{
388	x25_asy_lock(sl);
389	sl->stats.tx_bytes+=skb->len;
390	x25_asy_encaps(sl, skb->data, skb->len);
391	dev_kfree_skb(skb);
392	}
393	spin_unlock(&sl->lock);
394	}
395
396	/*
397	* LAPB connection establish/down information.
398	*/
399
400	static void x25_asy_connected(struct net_device *dev, int reason)
401	{
402	struct x25_asy *sl = dev->priv;
403	struct sk_buff *skb;
404	unsigned char *ptr;
405
406	if ((skb = dev_alloc_skb(1)) == NULL) {
407	printk(KERN_ERR "lapbeth: out of memory\n");
408	return;
409	}
410
411	ptr = skb_put(skb, 1);
412	*ptr = 0x01;
413
414	skb->protocol = x25_type_trans(skb, sl->dev);
415	netif_rx(skb);
416	sl->dev->last_rx = jiffies;
417	}
418
419	static void x25_asy_disconnected(struct net_device *dev, int reason)
420	{
421	struct x25_asy *sl = dev->priv;
422	struct sk_buff *skb;
423	unsigned char *ptr;
424
425	if ((skb = dev_alloc_skb(1)) == NULL) {
426	printk(KERN_ERR "x25_asy: out of memory\n");
427	return;
428	}
429
430	ptr = skb_put(skb, 1);
431	*ptr = 0x02;
432
433	skb->protocol = x25_type_trans(skb, sl->dev);
434	netif_rx(skb);
435	sl->dev->last_rx = jiffies;
436	}
437
438	static struct lapb_register_struct x25_asy_callbacks = {
439	.connect_confirmation = x25_asy_connected,
440	.connect_indication = x25_asy_connected,
441	.disconnect_confirmation = x25_asy_disconnected,
442	.disconnect_indication = x25_asy_disconnected,
443	.data_indication = x25_asy_data_indication,
444	.data_transmit = x25_asy_data_transmit,
445
446	};
447
448
449	/* Open the low-level part of the X.25 channel. Easy! */
450	static int x25_asy_open(struct net_device *dev)
451	{
452	struct x25_asy sl = (struct x25_asy)(dev->priv);
453	unsigned long len;
454	int err;
455
456	if (sl->tty == NULL)
457	return -ENODEV;
458
459	/*
460	* Allocate the X.25 frame buffers:
461	*
462	* rbuff Receive buffer.
463	* xbuff Transmit buffer.
464	*/
465
466	len = dev->mtu * 2;
467
5cbded58	468	sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
1da177e4 LT	469	if (sl->rbuff == NULL) {
	470	goto norbuff;
	471	}
5cbded58	472	sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
1da177e4 LT	473	if (sl->xbuff == NULL) {
	474	goto noxbuff;
	475	}
	476
	477	sl->buffsize = len;
	478	sl->rcount = 0;
	479	sl->xleft = 0;
	480	sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
	481
	482	netif_start_queue(dev);
	483
	484	/*
	485	* Now attach LAPB
	486	*/
	487	if((err=lapb_register(dev, &x25_asy_callbacks))==LAPB_OK)
	488	return 0;
	489
	490	/* Cleanup */
	491	kfree(sl->xbuff);
	492	noxbuff:
	493	kfree(sl->rbuff);
	494	norbuff:
	495	return -ENOMEM;
	496	}
	497
	498
	499	/* Close the low-level part of the X.25 channel. Easy! */
	500	static int x25_asy_close(struct net_device *dev)
	501	{
	502	struct x25_asy sl = (struct x25_asy)(dev->priv);
	503	int err;
	504
	505	spin_lock(&sl->lock);
	506	if (sl->tty)
	507	sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
	508
	509	netif_stop_queue(dev);
	510	sl->rcount = 0;
	511	sl->xleft = 0;
	512	if((err=lapb_unregister(dev))!=LAPB_OK)
	513	printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",err);
	514	spin_unlock(&sl->lock);
	515	return 0;
	516	}
	517
1da177e4 LT	518	/*
	519	* Handle the 'receiver data ready' interrupt.
	520	* This function is called by the 'tty_io' module in the kernel when
	521	* a block of X.25 data has been received, which can now be decapsulated
	522	* and sent on to some IP layer for further processing.
	523	*/
	524
	525	static void x25_asy_receive_buf(struct tty_struct tty, const unsigned char cp, char *fp, int count)
	526	{
	527	struct x25_asy sl = (struct x25_asy ) tty->disc_data;
	528
	529	if (!sl \|\| sl->magic != X25_ASY_MAGIC \|\| !netif_running(sl->dev))
	530	return;
	531
	532
	533	/* Read the characters out of the buffer */
	534	while (count--) {
	535	if (fp && *fp++) {
	536	if (!test_and_set_bit(SLF_ERROR, &sl->flags)) {
	537	sl->stats.rx_errors++;
	538	}
	539	cp++;
	540	continue;
	541	}
	542	x25_asy_unesc(sl, *cp++);
	543	}
	544	}
	545
	546	/*
	547	* Open the high-level part of the X.25 channel.
	548	* This function is called by the TTY module when the
	549	* X.25 line discipline is called for. Because we are
	550	* sure the tty line exists, we only have to link it to
	551	* a free X.25 channel...
	552	*/
	553
	554	static int x25_asy_open_tty(struct tty_struct *tty)
	555	{
	556	struct x25_asy sl = (struct x25_asy ) tty->disc_data;
	557	int err;
	558
	559	/* First make sure we're not already connected. */
	560	if (sl && sl->magic == X25_ASY_MAGIC) {
	561	return -EEXIST;
	562	}
	563
	564	/* OK. Find a free X.25 channel to use. */
	565	if ((sl = x25_asy_alloc()) == NULL) {
	566	return -ENFILE;
	567	}
	568
	569	sl->tty = tty;
	570	tty->disc_data = sl;
33f0f88f	571	tty->receive_room = 65536;
1da177e4 LT	572	if (tty->driver->flush_buffer) {
	573	tty->driver->flush_buffer(tty);
	574	}
11b0cc3a	575	tty_ldisc_flush(tty);
1da177e4 LT	576
	577	/* Restore default settings */
	578	sl->dev->type = ARPHRD_X25;
	579
	580	/* Perform the low-level X.25 async init */
	581	if ((err = x25_asy_open(sl->dev)))
	582	return err;
	583
	584	/* Done. We have linked the TTY line to a channel. */
	585	return sl->dev->base_addr;
	586	}
	587
	588
	589	/*
	590	* Close down an X.25 channel.
	591	* This means flushing out any pending queues, and then restoring the
	592	* TTY line discipline to what it was before it got hooked to X.25
	593	* (which usually is TTY again).
	594	*/
	595	static void x25_asy_close_tty(struct tty_struct *tty)
	596	{
	597	struct x25_asy sl = (struct x25_asy ) tty->disc_data;
	598
	599	/* First make sure we're connected. */
	600	if (!sl \|\| sl->magic != X25_ASY_MAGIC)
	601	return;
	602
	603	if (sl->dev->flags & IFF_UP)
	604	{
	605	(void) dev_close(sl->dev);
	606	}
	607
	608	tty->disc_data = NULL;
	609	sl->tty = NULL;
	610	x25_asy_free(sl);
	611	}
	612
	613
	614	static struct net_device_stats x25_asy_get_stats(struct net_device dev)
	615	{
	616	struct x25_asy sl = (struct x25_asy)(dev->priv);
	617
	618	return &sl->stats;
	619	}
	620
	621
	622	/************************************************************************
	623	* STANDARD X.25 ENCAPSULATION *
	624	************************************************************************/
	625
	626	int x25_asy_esc(unsigned char s, unsigned char d, int len)
	627	{
	628	unsigned char *ptr = d;
	629	unsigned char c;
	630
	631	/*
	632	* Send an initial END character to flush out any
	633	* data that may have accumulated in the receiver
	634	* due to line noise.
	635	*/
	636
	637	ptr++ = X25_END; / Send 10111110 bit seq */
	638
	639	/*
640	* For each byte in the packet, send the appropriate
641	* character sequence, according to the X.25 protocol.
642	*/
643
644	while (len-- > 0)
645	{
646	switch(c = *s++)
647	{
648	case X25_END:
649	*ptr++ = X25_ESC;
650	*ptr++ = X25_ESCAPE(X25_END);
651	break;
652	case X25_ESC:
653	*ptr++ = X25_ESC;
654	*ptr++ = X25_ESCAPE(X25_ESC);
655	break;
656	default:
657	*ptr++ = c;
658	break;
659	}
660	}
661	*ptr++ = X25_END;
662	return (ptr - d);
663	}
664
665	static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
666	{
667
668	switch(s)
669	{
670	case X25_END:
671	if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2))
672	{
673	x25_asy_bump(sl);
674	}
675	clear_bit(SLF_ESCAPE, &sl->flags);
676	sl->rcount = 0;
677	return;
678
679	case X25_ESC:
680	set_bit(SLF_ESCAPE, &sl->flags);
681	return;
682
683	case X25_ESCAPE(X25_ESC):
684	case X25_ESCAPE(X25_END):
685	if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
686	s = X25_UNESCAPE(s);
687	break;
688	}
689	if (!test_bit(SLF_ERROR, &sl->flags))
690	{
691	if (sl->rcount < sl->buffsize)
692	{
693	sl->rbuff[sl->rcount++] = s;
694	return;
695	}
696	sl->stats.rx_over_errors++;
697	set_bit(SLF_ERROR, &sl->flags);
698	}
699	}
700
701
702	/* Perform I/O control on an active X.25 channel. */
703	static int x25_asy_ioctl(struct tty_struct tty, struct file file,
704	unsigned int cmd, unsigned long arg)
705	{
706	struct x25_asy sl = (struct x25_asy ) tty->disc_data;
707
708	/* First make sure we're connected. */
709	if (!sl \|\| sl->magic != X25_ASY_MAGIC)
710	return -EINVAL;
711
712	switch(cmd) {
713	case SIOCGIFNAME:
714	if (copy_to_user((void __user *)arg, sl->dev->name,
715	strlen(sl->dev->name) + 1))
716	return -EFAULT;
717	return 0;
718	case SIOCSIFHWADDR:
719	return -EINVAL;
1da177e4	720	default:
d0127539	721	return tty_mode_ioctl(tty, file, cmd, arg);
1da177e4 LT	722	}
	723	}
	724
	725	static int x25_asy_open_dev(struct net_device *dev)
	726	{
	727	struct x25_asy sl = (struct x25_asy)(dev->priv);
	728	if(sl->tty==NULL)
	729	return -ENODEV;
	730	return 0;
	731	}
	732
	733	/* Initialise the X.25 driver. Called by the device init code */
	734	static void x25_asy_setup(struct net_device *dev)
	735	{
	736	struct x25_asy *sl = dev->priv;
	737
	738	sl->magic = X25_ASY_MAGIC;
	739	sl->dev = dev;
	740	spin_lock_init(&sl->lock);
	741	set_bit(SLF_INUSE, &sl->flags);
	742
	743	/*
	744	* Finish setting up the DEVICE info.
	745	*/
	746
	747	dev->mtu = SL_MTU;
	748	dev->hard_start_xmit = x25_asy_xmit;
	749	dev->tx_timeout = x25_asy_timeout;
	750	dev->watchdog_timeo = HZ*20;
	751	dev->open = x25_asy_open_dev;
	752	dev->stop = x25_asy_close;
	753	dev->get_stats = x25_asy_get_stats;
	754	dev->change_mtu = x25_asy_change_mtu;
	755	dev->hard_header_len = 0;
	756	dev->addr_len = 0;
	757	dev->type = ARPHRD_X25;
	758	dev->tx_queue_len = 10;
	759
	760	/* New-style flags. */
	761	dev->flags = IFF_NOARP;
	762	}
	763
	764	static struct tty_ldisc x25_ldisc = {
	765	.owner = THIS_MODULE,
	766	.magic = TTY_LDISC_MAGIC,
	767	.name = "X.25",
	768	.open = x25_asy_open_tty,
	769	.close = x25_asy_close_tty,
	770	.ioctl = x25_asy_ioctl,
	771	.receive_buf = x25_asy_receive_buf,
1da177e4 LT	772	.write_wakeup = x25_asy_write_wakeup,
	773	};
	774
	775	static int __init init_x25_asy(void)
	776	{
	777	if (x25_asy_maxdev < 4)
	778	x25_asy_maxdev = 4; /* Sanity */
	779
	780	printk(KERN_INFO "X.25 async: version 0.00 ALPHA "
	781	"(dynamic channels, max=%d).\n", x25_asy_maxdev );
	782
dd00cc48	783	x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device*), GFP_KERNEL);
1da177e4 LT	784	if (!x25_asy_devs) {
	785	printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] "
	786	"array! Uaargh! (-> No X.25 available)\n");
	787	return -ENOMEM;
	788	}
1da177e4 LT	789
	790	return tty_register_ldisc(N_X25, &x25_ldisc);
	791	}
	792
	793
	794	static void __exit exit_x25_asy(void)
	795	{
	796	struct net_device *dev;
	797	int i;
	798
	799	for (i = 0; i < x25_asy_maxdev; i++) {
	800	dev = x25_asy_devs[i];
	801	if (dev) {
	802	struct x25_asy *sl = dev->priv;
	803
	804	spin_lock_bh(&sl->lock);
	805	if (sl->tty)
	806	tty_hangup(sl->tty);
	807
	808	spin_unlock_bh(&sl->lock);
	809	/*
	810	* VSV = if dev->start==0, then device
	811	* unregistered while close proc.
	812	*/
	813	unregister_netdev(dev);
	814	free_netdev(dev);
	815	}
	816	}
	817
	818	kfree(x25_asy_devs);
64ccd715	819	tty_unregister_ldisc(N_X25);
1da177e4 LT	820	}
	821
	822	module_init(init_x25_asy);
	823	module_exit(exit_x25_asy);