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linux-sg2042/drivers/net/wan/x25_asy.c

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/*
* 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 = (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);
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 = (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;
}
/*
* 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);
}
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,
.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_unregister_ldisc(N_X25);
}
module_init(init_x25_asy);
module_exit(exit_x25_asy);
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