5 * o allow users to set the parameters
6 * o sync/async switching ?
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
14 * 2000-10-29 Henner Eisen lapb_data_indication() return status.
17 #include <linux/module.h>
19 #include <asm/system.h>
20 #include <asm/uaccess.h>
21 #include <linux/bitops.h>
22 #include <linux/string.h>
24 #include <linux/interrupt.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>
37 #include <net/x25device.h>
39 static struct net_device **x25_asy_devs;
40 static int x25_asy_maxdev = SL_NRUNIT;
42 module_param(x25_asy_maxdev, int, 0);
43 MODULE_LICENSE("GPL");
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);
49 /* Find a free X.25 channel, and link in this `tty' line. */
50 static struct x25_asy *x25_asy_alloc(void)
52 struct net_device *dev = NULL;
56 if (x25_asy_devs == NULL)
57 return NULL; /* Master array missing ! */
59 for (i = 0; i < x25_asy_maxdev; i++) {
60 dev = x25_asy_devs[i];
68 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
73 /* Sorry, too many, all slots in use */
74 if (i >= x25_asy_maxdev)
77 /* If no channels are available, allocate one */
80 sprintf(name, "x25asy%d", i);
82 dev = alloc_netdev(sizeof(struct x25_asy),
87 /* Initialize channel control data */
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;
98 printk("x25_asy_alloc() - register_netdev() failure.\n");
106 /* Free an X.25 channel. */
107 static void x25_asy_free(struct x25_asy *sl)
109 /* Free all X.25 frame buffers. */
119 if (!test_and_clear_bit(SLF_INUSE, &sl->flags)) {
120 printk("%s: x25_asy_free for already free unit.\n", sl->dev->name);
124 static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
126 struct x25_asy *sl = dev->priv;
127 unsigned char *xbuff, *rbuff;
130 xbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
131 rbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
133 if (xbuff == NULL || rbuff == NULL)
135 printk("%s: unable to grow X.25 buffers, MTU change cancelled.\n",
144 spin_lock_bh(&sl->lock);
145 xbuff = xchg(&sl->xbuff, xbuff);
147 if (sl->xleft <= len) {
148 memcpy(sl->xbuff, sl->xhead, sl->xleft);
151 sl->stats.tx_dropped++;
154 sl->xhead = sl->xbuff;
156 rbuff = xchg(&sl->rbuff, rbuff);
158 if (sl->rcount <= len) {
159 memcpy(sl->rbuff, rbuff, sl->rcount);
162 sl->stats.rx_over_errors++;
163 set_bit(SLF_ERROR, &sl->flags);
170 spin_unlock_bh(&sl->lock);
180 /* Set the "sending" flag. This must be atomic, hence the ASM. */
182 static inline void x25_asy_lock(struct x25_asy *sl)
184 netif_stop_queue(sl->dev);
188 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
190 static inline void x25_asy_unlock(struct x25_asy *sl)
192 netif_wake_queue(sl->dev);
195 /* Send one completely decapsulated IP datagram to the IP layer. */
197 static void x25_asy_bump(struct x25_asy *sl)
204 sl->stats.rx_bytes+=count;
206 skb = dev_alloc_skb(count+1);
209 printk("%s: memory squeeze, dropping packet.\n", sl->dev->name);
210 sl->stats.rx_dropped++;
213 skb_push(skb,1); /* LAPB internal control */
214 memcpy(skb_put(skb,count), sl->rbuff, count);
215 skb->protocol = x25_type_trans(skb, sl->dev);
216 if((err=lapb_data_received(skb->dev, skb))!=LAPB_OK)
219 printk(KERN_DEBUG "x25_asy: data received err - %d\n",err);
224 sl->dev->last_rx = jiffies;
225 sl->stats.rx_packets++;
229 /* Encapsulate one IP datagram and stuff into a TTY queue. */
230 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
233 int actual, count, mtu = sl->dev->mtu;
236 { /* Sigh, shouldn't occur BUT ... */
238 printk ("%s: truncating oversized transmit packet!\n", sl->dev->name);
239 sl->stats.tx_dropped++;
245 count = x25_asy_esc(p, (unsigned char *) sl->xbuff, len);
247 /* Order of next two lines is *very* important.
248 * When we are sending a little amount of data,
249 * the transfer may be completed inside driver.write()
250 * routine, because it's running with interrupts enabled.
251 * In this case we *never* got WRITE_WAKEUP event,
252 * if we did not request it before write operation.
253 * 14 Oct 1994 Dmitry Gorodchanin.
255 sl->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
256 actual = sl->tty->driver->write(sl->tty, sl->xbuff, count);
257 sl->xleft = count - actual;
258 sl->xhead = sl->xbuff + actual;
260 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
264 * Called by the driver when there's room for more data. If we have
265 * more packets to send, we send them here.
267 static void x25_asy_write_wakeup(struct tty_struct *tty)
270 struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
272 /* First make sure we're connected. */
273 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
278 /* Now serial buffer is almost free & we can start
279 * transmission of another packet */
280 sl->stats.tx_packets++;
281 tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
286 actual = tty->driver->write(tty, sl->xhead, sl->xleft);
291 static void x25_asy_timeout(struct net_device *dev)
293 struct x25_asy *sl = (struct x25_asy*)(dev->priv);
295 spin_lock(&sl->lock);
296 if (netif_queue_stopped(dev)) {
297 /* May be we must check transmitter timeout here ?
298 * 14 Oct 1994 Dmitry Gorodchanin.
300 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
301 (sl->tty->driver->chars_in_buffer(sl->tty) || sl->xleft) ?
302 "bad line quality" : "driver error");
304 sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
307 spin_unlock(&sl->lock);
310 /* Encapsulate an IP datagram and kick it into a TTY queue. */
312 static int x25_asy_xmit(struct sk_buff *skb, struct net_device *dev)
314 struct x25_asy *sl = (struct x25_asy*)(dev->priv);
317 if (!netif_running(sl->dev)) {
318 printk("%s: xmit call when iface is down\n", dev->name);
326 case 0x01: /* Connection request .. do nothing */
327 if((err=lapb_connect_request(dev))!=LAPB_OK)
328 printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
331 case 0x02: /* Disconnect request .. do nothing - hang up ?? */
332 if((err=lapb_disconnect_request(dev))!=LAPB_OK)
333 printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
338 skb_pull(skb,1); /* Remove control byte */
340 * If we are busy already- too bad. We ought to be able
341 * to queue things at this point, to allow for a little
342 * frame buffer. Oh well...
343 * -----------------------------------------------------
344 * I hate queues in X.25 driver. May be it's efficient,
345 * but for me latency is more important. ;)
347 * 14 Oct 1994 Dmitry Gorodchanin.
350 if((err=lapb_data_request(dev,skb))!=LAPB_OK)
352 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
361 * LAPB interface boilerplate
365 * Called when I frame data arrives. We did the work above - throw it
369 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
371 skb->dev->last_rx = jiffies;
372 return netif_rx(skb);
376 * Data has emerged from the LAPB protocol machine. We don't handle
377 * busy cases too well. Its tricky to see how to do this nicely -
378 * perhaps lapb should allow us to bounce this ?
381 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
383 struct x25_asy *sl=dev->priv;
385 spin_lock(&sl->lock);
386 if (netif_queue_stopped(sl->dev) || sl->tty == NULL)
388 spin_unlock(&sl->lock);
389 printk(KERN_ERR "x25_asy: tbusy drop\n");
393 /* We were not busy, so we are now... :-) */
397 sl->stats.tx_bytes+=skb->len;
398 x25_asy_encaps(sl, skb->data, skb->len);
401 spin_unlock(&sl->lock);
405 * LAPB connection establish/down information.
408 static void x25_asy_connected(struct net_device *dev, int reason)
410 struct x25_asy *sl = dev->priv;
414 if ((skb = dev_alloc_skb(1)) == NULL) {
415 printk(KERN_ERR "lapbeth: out of memory\n");
419 ptr = skb_put(skb, 1);
422 skb->protocol = x25_type_trans(skb, sl->dev);
424 sl->dev->last_rx = jiffies;
427 static void x25_asy_disconnected(struct net_device *dev, int reason)
429 struct x25_asy *sl = dev->priv;
433 if ((skb = dev_alloc_skb(1)) == NULL) {
434 printk(KERN_ERR "x25_asy: out of memory\n");
438 ptr = skb_put(skb, 1);
441 skb->protocol = x25_type_trans(skb, sl->dev);
443 sl->dev->last_rx = jiffies;
446 static struct lapb_register_struct x25_asy_callbacks = {
447 .connect_confirmation = x25_asy_connected,
448 .connect_indication = x25_asy_connected,
449 .disconnect_confirmation = x25_asy_disconnected,
450 .disconnect_indication = x25_asy_disconnected,
451 .data_indication = x25_asy_data_indication,
452 .data_transmit = x25_asy_data_transmit,
457 /* Open the low-level part of the X.25 channel. Easy! */
458 static int x25_asy_open(struct net_device *dev)
460 struct x25_asy *sl = (struct x25_asy*)(dev->priv);
468 * Allocate the X.25 frame buffers:
470 * rbuff Receive buffer.
471 * xbuff Transmit buffer.
476 sl->rbuff = (unsigned char *) kmalloc(len + 4, GFP_KERNEL);
477 if (sl->rbuff == NULL) {
480 sl->xbuff = (unsigned char *) kmalloc(len + 4, GFP_KERNEL);
481 if (sl->xbuff == NULL) {
488 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
490 netif_start_queue(dev);
495 if((err=lapb_register(dev, &x25_asy_callbacks))==LAPB_OK)
507 /* Close the low-level part of the X.25 channel. Easy! */
508 static int x25_asy_close(struct net_device *dev)
510 struct x25_asy *sl = (struct x25_asy*)(dev->priv);
513 spin_lock(&sl->lock);
515 sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
517 netif_stop_queue(dev);
520 if((err=lapb_unregister(dev))!=LAPB_OK)
521 printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",err);
522 spin_unlock(&sl->lock);
526 static int x25_asy_receive_room(struct tty_struct *tty)
528 return 65536; /* We can handle an infinite amount of data. :-) */
532 * Handle the 'receiver data ready' interrupt.
533 * This function is called by the 'tty_io' module in the kernel when
534 * a block of X.25 data has been received, which can now be decapsulated
535 * and sent on to some IP layer for further processing.
538 static void x25_asy_receive_buf(struct tty_struct *tty, const unsigned char *cp, char *fp, int count)
540 struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
542 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
546 /* Read the characters out of the buffer */
549 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) {
550 sl->stats.rx_errors++;
555 x25_asy_unesc(sl, *cp++);
560 * Open the high-level part of the X.25 channel.
561 * This function is called by the TTY module when the
562 * X.25 line discipline is called for. Because we are
563 * sure the tty line exists, we only have to link it to
564 * a free X.25 channel...
567 static int x25_asy_open_tty(struct tty_struct *tty)
569 struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
572 /* First make sure we're not already connected. */
573 if (sl && sl->magic == X25_ASY_MAGIC) {
577 /* OK. Find a free X.25 channel to use. */
578 if ((sl = x25_asy_alloc()) == NULL) {
584 if (tty->driver->flush_buffer) {
585 tty->driver->flush_buffer(tty);
587 if (tty->ldisc.flush_buffer) {
588 tty->ldisc.flush_buffer(tty);
591 /* Restore default settings */
592 sl->dev->type = ARPHRD_X25;
594 /* Perform the low-level X.25 async init */
595 if ((err = x25_asy_open(sl->dev)))
598 /* Done. We have linked the TTY line to a channel. */
599 return sl->dev->base_addr;
604 * Close down an X.25 channel.
605 * This means flushing out any pending queues, and then restoring the
606 * TTY line discipline to what it was before it got hooked to X.25
607 * (which usually is TTY again).
609 static void x25_asy_close_tty(struct tty_struct *tty)
611 struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
613 /* First make sure we're connected. */
614 if (!sl || sl->magic != X25_ASY_MAGIC)
617 if (sl->dev->flags & IFF_UP)
619 (void) dev_close(sl->dev);
622 tty->disc_data = NULL;
628 static struct net_device_stats *x25_asy_get_stats(struct net_device *dev)
630 struct x25_asy *sl = (struct x25_asy*)(dev->priv);
636 /************************************************************************
637 * STANDARD X.25 ENCAPSULATION *
638 ************************************************************************/
640 int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
642 unsigned char *ptr = d;
646 * Send an initial END character to flush out any
647 * data that may have accumulated in the receiver
651 *ptr++ = X25_END; /* Send 10111110 bit seq */
654 * For each byte in the packet, send the appropriate
655 * character sequence, according to the X.25 protocol.
664 *ptr++ = X25_ESCAPE(X25_END);
668 *ptr++ = X25_ESCAPE(X25_ESC);
679 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
685 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2))
689 clear_bit(SLF_ESCAPE, &sl->flags);
694 set_bit(SLF_ESCAPE, &sl->flags);
697 case X25_ESCAPE(X25_ESC):
698 case X25_ESCAPE(X25_END):
699 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
703 if (!test_bit(SLF_ERROR, &sl->flags))
705 if (sl->rcount < sl->buffsize)
707 sl->rbuff[sl->rcount++] = s;
710 sl->stats.rx_over_errors++;
711 set_bit(SLF_ERROR, &sl->flags);
716 /* Perform I/O control on an active X.25 channel. */
717 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
718 unsigned int cmd, unsigned long arg)
720 struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
722 /* First make sure we're connected. */
723 if (!sl || sl->magic != X25_ASY_MAGIC)
728 if (copy_to_user((void __user *)arg, sl->dev->name,
729 strlen(sl->dev->name) + 1))
734 /* Allow stty to read, but not set, the serial port */
737 return n_tty_ioctl(tty, file, cmd, arg);
743 static int x25_asy_open_dev(struct net_device *dev)
745 struct x25_asy *sl = (struct x25_asy*)(dev->priv);
751 /* Initialise the X.25 driver. Called by the device init code */
752 static void x25_asy_setup(struct net_device *dev)
754 struct x25_asy *sl = dev->priv;
756 sl->magic = X25_ASY_MAGIC;
758 spin_lock_init(&sl->lock);
759 set_bit(SLF_INUSE, &sl->flags);
762 * Finish setting up the DEVICE info.
766 dev->hard_start_xmit = x25_asy_xmit;
767 dev->tx_timeout = x25_asy_timeout;
768 dev->watchdog_timeo = HZ*20;
769 dev->open = x25_asy_open_dev;
770 dev->stop = x25_asy_close;
771 dev->get_stats = x25_asy_get_stats;
772 dev->change_mtu = x25_asy_change_mtu;
773 dev->hard_header_len = 0;
775 dev->type = ARPHRD_X25;
776 dev->tx_queue_len = 10;
778 /* New-style flags. */
779 dev->flags = IFF_NOARP;
782 static struct tty_ldisc x25_ldisc = {
783 .owner = THIS_MODULE,
784 .magic = TTY_LDISC_MAGIC,
786 .open = x25_asy_open_tty,
787 .close = x25_asy_close_tty,
788 .ioctl = x25_asy_ioctl,
789 .receive_buf = x25_asy_receive_buf,
790 .receive_room = x25_asy_receive_room,
791 .write_wakeup = x25_asy_write_wakeup,
794 static int __init init_x25_asy(void)
796 if (x25_asy_maxdev < 4)
797 x25_asy_maxdev = 4; /* Sanity */
799 printk(KERN_INFO "X.25 async: version 0.00 ALPHA "
800 "(dynamic channels, max=%d).\n", x25_asy_maxdev );
802 x25_asy_devs = kmalloc(sizeof(struct net_device *)*x25_asy_maxdev,
805 printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] "
806 "array! Uaargh! (-> No X.25 available)\n");
809 memset(x25_asy_devs, 0, sizeof(struct net_device *)*x25_asy_maxdev);
811 return tty_register_ldisc(N_X25, &x25_ldisc);
815 static void __exit exit_x25_asy(void)
817 struct net_device *dev;
820 for (i = 0; i < x25_asy_maxdev; i++) {
821 dev = x25_asy_devs[i];
823 struct x25_asy *sl = dev->priv;
825 spin_lock_bh(&sl->lock);
829 spin_unlock_bh(&sl->lock);
831 * VSV = if dev->start==0, then device
832 * unregistered while close proc.
834 unregister_netdev(dev);
840 tty_register_ldisc(N_X25, NULL);
843 module_init(init_x25_asy);
844 module_exit(exit_x25_asy);