x25_asy.c

powerpc内核mpc8241linux系统下net驱动程序

	skb->protocol = htons(ETH_P_X25);
	skb->mac.raw  = skb->data;
	skb->pkt_type = PACKET_HOST;

	netif_rx(skb);
}


/* Open the low-level part of the X.25 channel. Easy! */

static int x25_asy_open(struct device *dev)
{
	struct lapb_register_struct x25_asy_callbacks;
	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->mtu	     = dev->mtu;
	sl->buffsize = len;
	sl->rcount   = 0;
	sl->xleft    = 0;
	sl->flags   &= (1 << SLF_INUSE);      /* Clear ESCAPE & ERROR flags */

	dev->tbusy  = 0;
/*	dev->flags |= IFF_UP; */
	dev->start  = 1;
	
	/*
	 *	Now attach LAPB
	 */
	 
	x25_asy_callbacks.connect_confirmation=x25_asy_connected;
	x25_asy_callbacks.connect_indication=x25_asy_connected;
	x25_asy_callbacks.disconnect_confirmation=x25_asy_disconnected;
	x25_asy_callbacks.disconnect_indication=x25_asy_disconnected;
	x25_asy_callbacks.data_indication=x25_asy_data_indication;
	x25_asy_callbacks.data_transmit=x25_asy_data_transmit;

	if((err=lapb_register(sl, &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 device *dev)
{
	struct x25_asy *sl = (struct x25_asy*)(dev->priv);
	int err;

	if (sl->tty == NULL)
		return -EBUSY;

	sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
	dev->tbusy = 1;
	dev->start = 0;
	if((err=lapb_unregister(sl))!=LAPB_OK)
		printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",err);

/*	dev->flags &= ~IFF_UP; */
	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 || !sl->dev->start)
		return;

	/*
	 * Argh! mtu change time! - costs us the packet part received
	 * at the change
	 */
	if (sl->mtu != sl->dev->mtu)  {

		x25_asy_changed_mtu(sl);
	}

	/* Read the characters out of the buffer */
	while (count--) {
		if (fp && *fp++) {
			if (!test_and_set_bit(SLF_ERROR, &sl->flags))  {
				sl->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;

	MOD_INC_USE_COUNT;

	/* 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)
	{
		dev_lock_wait();
		(void) dev_close(sl->dev);
		dev_unlock_list();
	}

	tty->disc_data = 0;
	sl->tty = NULL;
	x25_asy_free(sl);
	unregister_netdev(sl->dev);
	MOD_DEC_USE_COUNT;
}


static struct net_device_stats *x25_asy_get_stats(struct device *dev)
{
	static struct net_device_stats stats;
	struct x25_asy *sl = (struct x25_asy*)(dev->priv);

	memset(&stats, 0, sizeof(struct net_device_stats));

	stats.rx_packets     = sl->rx_packets;
	stats.tx_packets     = sl->tx_packets;
	stats.rx_bytes	     = sl->rx_bytes;
	stats.tx_bytes	     = sl->tx_bytes;
	stats.rx_dropped     = sl->rx_dropped;
	stats.tx_dropped     = sl->tx_dropped;
	stats.tx_errors      = sl->tx_errors;
	stats.rx_errors      = sl->rx_errors;
	stats.rx_over_errors = sl->rx_over_errors;
	return (&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->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, void *file, int cmd, void *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(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, (struct file *) file, cmd, (unsigned long) arg);

		default:
			return -ENOIOCTLCMD;
	}
}

static int x25_asy_open_dev(struct device *dev)
{
	struct x25_asy *sl = (struct x25_asy*)(dev->priv);
	if(sl->tty==NULL)
		return -ENODEV;
	return 0;
}

/* Initialize X.25 control device -- register X.25 line discipline */
#ifdef MODULE
static int x25_asy_init_ctrl_dev(void)
#else	/* !MODULE */
__initfunc(int x25_asy_init_ctrl_dev(struct device *dummy))
#endif	/* !MODULE */
{
	int status;

	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_ctrls = (x25_asy_ctrl_t **) kmalloc(sizeof(void*)*x25_asy_maxdev, GFP_KERNEL);
	if (x25_asy_ctrls == NULL)
	{
		printk("X25 async: Can't allocate x25_asy_ctrls[] array!  Uaargh! (-> No X.25 available)\n");
		return -ENOMEM;
	}

	/* Clear the pointer array, we allocate devices when we need them */
	memset(x25_asy_ctrls, 0, sizeof(void*)*x25_asy_maxdev); /* Pointers */

	/* Fill in our line protocol discipline, and register it */
	memset(&x25_ldisc, 0, sizeof(x25_ldisc));
	x25_ldisc.magic  = TTY_LDISC_MAGIC;
	x25_ldisc.name   = "X.25";
	x25_ldisc.flags  = 0;
	x25_ldisc.open   = x25_asy_open_tty;
	x25_ldisc.close  = x25_asy_close_tty;
	x25_ldisc.read   = NULL;
	x25_ldisc.write  = NULL;
	x25_ldisc.ioctl  = (int (*)(struct tty_struct *, struct file *,
				   unsigned int, unsigned long)) x25_asy_ioctl;
	x25_ldisc.poll   = NULL;
	x25_ldisc.receive_buf = x25_asy_receive_buf;
	x25_ldisc.receive_room = x25_asy_receive_room;
	x25_ldisc.write_wakeup = x25_asy_write_wakeup;
	if ((status = tty_register_ldisc(N_X25, &x25_ldisc)) != 0)  {
		printk("X.25 async: can't register line discipline (err = %d)\n", status);
	}

#ifdef MODULE
	return status;
#else
	/* Return "not found", so that dev_init() will unlink
	 * the placeholder device entry for us.
	 */
	return ENODEV;
#endif
      }


/* Initialise the X.25 driver.  Called by the device init code */

int x25_asy_init(struct device *dev)
{
	struct x25_asy *sl = (struct x25_asy*)(dev->priv);

	if (sl == NULL)		/* Allocation failed ?? */
		return -ENODEV;

	/* Set up the control block. (And clear statistics) */

	memset(sl, 0, sizeof (struct x25_asy));
	sl->magic  = X25_ASY_MAGIC;
	sl->dev	   = dev;

	/*
	 *	Finish setting up the DEVICE info. 
	 */
	 
	dev->mtu		= SL_MTU;
	dev->hard_start_xmit	= x25_asy_xmit;
	dev->open		= x25_asy_open_dev;
	dev->stop		= x25_asy_close;
	dev->get_stats	        = x25_asy_get_stats;
	dev->hard_header_len	= 0;
	dev->addr_len		= 0;
	dev->type		= ARPHRD_X25;
	dev->tx_queue_len	= 10;

	dev_init_buffers(dev);
	
	/* New-style flags. */
	dev->flags		= IFF_NOARP;

	return 0;
}
#ifdef MODULE

int
init_module(void)
{
	return x25_asy_init_ctrl_dev();
}

void
cleanup_module(void)
{
	int i;

	if (x25_asy_ctrls != NULL)
	{
		for (i = 0; i < x25_asy_maxdev; i++)
		{
			if (x25_asy_ctrls[i])
			{
				/*
				 * VSV = if dev->start==0, then device
				 * unregistered while close proc.
				 */
				if (x25_asy_ctrls[i]->dev.start)
					unregister_netdev(&(x25_asy_ctrls[i]->dev));

				kfree(x25_asy_ctrls[i]);
				x25_asy_ctrls[i] = NULL;
			}
		}
		kfree(x25_asy_ctrls);
		x25_asy_ctrls = NULL;
	}
	if ((i = tty_register_ldisc(N_X25, NULL)))
	{
		printk("X.25 async: can't unregister line discipline (err = %d)\n", i);
	}
}
#endif /* MODULE */