- 根目录:
- 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <asm/system.h>
#include <linux/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/lapb.h>
#include <linux/init.h>
#include <linux/rtnetlink.h>
#include <linux/compat.h>
#include <linux/slab.h>
#include <net/x25device.h>
#include "x25_asy.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 = netdev_priv(dev);
/* 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 = netdev_priv(dev);
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 {
pr_warn("%s(): register_netdev() failure\n", __func__);
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))
netdev_err(sl->dev, "x25_asy_free for already free unit\n");
}
static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
{
struct x25_asy *sl = netdev_priv(dev);
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) {
netdev_warn(dev, "unable to grow X.25 buffers, MTU change cancelled\n");
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;
dev->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;
dev->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 net_device *dev = sl->dev;
struct sk_buff *skb;
int count;
int err;
count = sl->rcount;
dev->stats.rx_bytes += count;
skb = dev_alloc_skb(count+1);
if (skb == NULL) {
netdev_warn(sl->dev, "memory squeeze, dropping packet\n");
dev->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);
err = lapb_data_received(skb->dev, skb);
if (err != LAPB_OK) {
kfree_skb(skb);
printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
} else {
netif_rx(skb);
dev->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(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
sl->dev->name);
sl->dev->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.
*/
set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
actual = sl->tty->ops->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 = 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->dev->stats.tx_packets++;
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
x25_asy_unlock(sl);
return;
}
actual = tty->ops->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 = netdev_priv(dev);
spin_lock(&sl->lock);
if (netif_queue_stopped(dev)) {
/* May be we must check transmitter timeout here ?
* 14 Oct 1994 Dmitry Gorodchanin.
*/
netdev_warn(dev, "transmit timed out, %s?\n",
(tty_chars_in_buffer(sl->tty) || sl->xleft) ?
"bad line quality" : "driver error");
sl->xleft = 0;
clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
x25_asy_unlock(sl);
}
spin_unlock(&sl->lock);
}
/* Encapsulate an IP datagram and kick it into a TTY queue. */
static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct x25_asy *sl = netdev_priv(dev);
int err;
if (!netif_running(sl->dev)) {
netdev_err(dev, "xmit call when iface is down\n");
kfree_skb(skb);
return NETDEV_TX_OK;
}
switch (skb->data[0]) {
case X25_IFACE_DATA:
break;
case X25_IFACE_CONNECT: /* Connection request .. do nothing */
err = lapb_connect_request(dev);
if (err != LAPB_OK)
netdev_err(dev, "lapb_connect_request error: %d\n",
err);
kfree_skb(skb);
return NETDEV_TX_OK;
case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
err = lapb_disconnect_request(dev);
if (err != LAPB_OK)
netdev_err(dev, "lapb_disconnect_request error: %d\n",
err);
default:
kfree_skb(skb);
return NETDEV_TX_OK;
}
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.
*/
err = lapb_data_request(dev, skb);
if (err != LAPB_OK) {
netdev_err(dev, "lapb_data_request error: %d\n", err);
kfree_skb(skb);
return NETDEV_TX_OK;
}
return NETDEV_TX_OK;
}
/*
* 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)
{
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 = netdev_priv(dev);
spin_lock(&sl->lock);
if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
spin_unlock(&sl->lock);
netdev_err(dev, "tbusy drop\n");
kfree_skb(skb);
return;
}
/* We were not busy, so we are now... :-) */
if (skb != NULL) {
x25_asy_lock(sl);
dev->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 = netdev_priv(dev);
struct sk_buff *skb;
unsigned char *ptr;
skb = dev_alloc_skb(1);
if (skb == NULL) {
netdev_err(dev, "out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = X25_IFACE_CONNECT;
skb->protocol = x25_type_trans(skb, sl->dev);
netif_rx(skb);
}
static void x25_asy_disconnected(struct net_device *dev, int reason)
{
struct x25_asy *sl = netdev_priv(dev);
struct sk_buff *skb;
unsigned char *ptr;
skb = dev_alloc_skb(1);
if (skb == NULL) {
netdev_err(dev, "out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = X25_IFACE_DISCONNECT;
skb->protocol = x25_type_trans(skb, sl->dev);
netif_rx(skb);
}
static const 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 = netdev_priv(dev);
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
*/
err = lapb_register(dev, &x25_asy_callbacks);
if (err == 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 = netdev_priv(dev);
spin_lock(&sl->lock);
if (sl->tty)
clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
netif_stop_queue(dev);
sl->rcount = 0;
sl->xleft = 0;
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 = 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->dev->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 = tty->disc_data;
int err;
if (tty->ops->write == NULL)
return -EOPNOTSUPP;
/* 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. */
sl = x25_asy_alloc();
if (sl == NULL)
return -ENFILE;
sl->tty = tty;
tty->disc_data = sl;
tty->receive_room = 65536;
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 */
err = x25_asy_open(sl->dev);
if (err)
return err;
/* Done. We have linked the TTY line to a channel. */
return 0;
}
/*
* 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 = tty->disc_data;
int err;
/* First make sure we're connected. */
if (!sl || sl->magic != X25_ASY_MAGIC)
return;
rtnl_lock();
if (sl->dev->flags & IFF_UP)
dev_close(sl->dev);
rtnl_unlock();
err = lapb_unregister(sl->dev);
if (err != LAPB_OK)
pr_err("x25_asy_close: lapb_unregister error: %d\n",
err);
tty->disc_data = NULL;
sl->tty = NULL;
x25_asy_free(sl);
}
/************************************************************************
* STANDARD X.25 ENCAPSULATION *
************************************************************************/
static 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->dev->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 = 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);
}
}
#ifdef CONFIG_COMPAT
static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case SIOCGIFNAME:
case SIOCSIFHWADDR:
return x25_asy_ioctl(tty, file, cmd,
(unsigned long)compat_ptr(arg));
}
return -ENOIOCTLCMD;
}
#endif
static int x25_asy_open_dev(struct net_device *dev)
{
struct x25_asy *sl = netdev_priv(dev);
if (sl->tty == NULL)
return -ENODEV;
return 0;
}
static const struct net_device_ops x25_asy_netdev_ops = {
.ndo_open = x25_asy_open_dev,
.ndo_stop = x25_asy_close,
.ndo_start_xmit = x25_asy_xmit,
.ndo_tx_timeout = x25_asy_timeout,
.ndo_change_mtu = x25_asy_change_mtu,
};
/* Initialise the X.25 driver. Called by the device init code */
static void x25_asy_setup(struct net_device *dev)
{
struct x25_asy *sl = netdev_priv(dev);
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->netdev_ops = &x25_asy_netdev_ops;
dev->watchdog_timeo = HZ*20;
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_ops 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,
#ifdef CONFIG_COMPAT
.compat_ioctl = x25_asy_compat_ioctl,
#endif
.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 */
pr_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) {
pr_warn("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 = netdev_priv(dev);
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);