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 <linux/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>
35 #include <linux/rtnetlink.h>
36 #include <linux/compat.h>
39 #include <net/x25device.h>
41 static struct net_device **x25_asy_devs;
42 static int x25_asy_maxdev = SL_NRUNIT;
44 module_param(x25_asy_maxdev, int, 0);
45 MODULE_LICENSE("GPL");
47 static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
48 static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
49 static void x25_asy_setup(struct net_device *dev);
51 /* Find a free X.25 channel, and link in this `tty' line. */
52 static struct x25_asy *x25_asy_alloc(void)
54 struct net_device *dev = NULL;
58 if (x25_asy_devs == NULL)
59 return NULL; /* Master array missing ! */
61 for (i = 0; i < x25_asy_maxdev; i++) {
62 dev = x25_asy_devs[i];
68 sl = netdev_priv(dev);
70 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
75 /* Sorry, too many, all slots in use */
76 if (i >= x25_asy_maxdev)
79 /* If no channels are available, allocate one */
82 sprintf(name, "x25asy%d", i);
84 dev = alloc_netdev(sizeof(struct x25_asy),
89 /* Initialize channel control data */
90 sl = netdev_priv(dev);
93 /* register device so that it can be ifconfig'ed */
94 if (register_netdev(dev) == 0) {
95 /* (Re-)Set the INUSE bit. Very Important! */
96 set_bit(SLF_INUSE, &sl->flags);
97 x25_asy_devs[i] = dev;
100 printk(KERN_WARNING "x25_asy_alloc() - register_netdev() failure.\n");
108 /* Free an X.25 channel. */
109 static void x25_asy_free(struct x25_asy *sl)
111 /* Free all X.25 frame buffers. */
117 if (!test_and_clear_bit(SLF_INUSE, &sl->flags))
118 printk(KERN_ERR "%s: x25_asy_free for already free unit.\n",
122 static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
124 struct x25_asy *sl = netdev_priv(dev);
125 unsigned char *xbuff, *rbuff;
126 int len = 2 * newmtu;
128 xbuff = kmalloc(len + 4, GFP_ATOMIC);
129 rbuff = kmalloc(len + 4, GFP_ATOMIC);
131 if (xbuff == NULL || rbuff == NULL) {
132 printk(KERN_WARNING "%s: unable to grow X.25 buffers, MTU change cancelled.\n",
139 spin_lock_bh(&sl->lock);
140 xbuff = xchg(&sl->xbuff, xbuff);
142 if (sl->xleft <= len) {
143 memcpy(sl->xbuff, sl->xhead, sl->xleft);
146 dev->stats.tx_dropped++;
149 sl->xhead = sl->xbuff;
151 rbuff = xchg(&sl->rbuff, rbuff);
153 if (sl->rcount <= len) {
154 memcpy(sl->rbuff, rbuff, sl->rcount);
157 dev->stats.rx_over_errors++;
158 set_bit(SLF_ERROR, &sl->flags);
165 spin_unlock_bh(&sl->lock);
173 /* Set the "sending" flag. This must be atomic, hence the ASM. */
175 static inline void x25_asy_lock(struct x25_asy *sl)
177 netif_stop_queue(sl->dev);
181 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
183 static inline void x25_asy_unlock(struct x25_asy *sl)
185 netif_wake_queue(sl->dev);
188 /* Send one completely decapsulated IP datagram to the IP layer. */
190 static void x25_asy_bump(struct x25_asy *sl)
192 struct net_device *dev = sl->dev;
198 dev->stats.rx_bytes += count;
200 skb = dev_alloc_skb(count+1);
202 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n",
204 dev->stats.rx_dropped++;
207 skb_push(skb, 1); /* LAPB internal control */
208 memcpy(skb_put(skb, count), sl->rbuff, count);
209 skb->protocol = x25_type_trans(skb, sl->dev);
210 err = lapb_data_received(skb->dev, skb);
211 if (err != LAPB_OK) {
213 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
216 dev->stats.rx_packets++;
220 /* Encapsulate one IP datagram and stuff into a TTY queue. */
221 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
224 int actual, count, mtu = sl->dev->mtu;
227 /* Sigh, shouldn't occur BUT ... */
229 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
231 sl->dev->stats.tx_dropped++;
237 count = x25_asy_esc(p, (unsigned char *) sl->xbuff, len);
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.
247 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
248 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
249 sl->xleft = count - actual;
250 sl->xhead = sl->xbuff + actual;
252 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
256 * Called by the driver when there's room for more data. If we have
257 * more packets to send, we send them here.
259 static void x25_asy_write_wakeup(struct tty_struct *tty)
262 struct x25_asy *sl = tty->disc_data;
264 /* First make sure we're connected. */
265 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
268 if (sl->xleft <= 0) {
269 /* Now serial buffer is almost free & we can start
270 * transmission of another packet */
271 sl->dev->stats.tx_packets++;
272 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
277 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
282 static void x25_asy_timeout(struct net_device *dev)
284 struct x25_asy *sl = netdev_priv(dev);
286 spin_lock(&sl->lock);
287 if (netif_queue_stopped(dev)) {
288 /* May be we must check transmitter timeout here ?
289 * 14 Oct 1994 Dmitry Gorodchanin.
291 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
292 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
293 "bad line quality" : "driver error");
295 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
298 spin_unlock(&sl->lock);
301 /* Encapsulate an IP datagram and kick it into a TTY queue. */
303 static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
304 struct net_device *dev)
306 struct x25_asy *sl = netdev_priv(dev);
309 if (!netif_running(sl->dev)) {
310 printk(KERN_ERR "%s: xmit call when iface is down\n",
316 switch (skb->data[0]) {
319 case 0x01: /* Connection request .. do nothing */
320 err = lapb_connect_request(dev);
322 printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
325 case 0x02: /* Disconnect request .. do nothing - hang up ?? */
326 err = lapb_disconnect_request(dev);
328 printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
333 skb_pull(skb, 1); /* Remove control byte */
335 * If we are busy already- too bad. We ought to be able
336 * to queue things at this point, to allow for a little
337 * frame buffer. Oh well...
338 * -----------------------------------------------------
339 * I hate queues in X.25 driver. May be it's efficient,
340 * but for me latency is more important. ;)
342 * 14 Oct 1994 Dmitry Gorodchanin.
345 err = lapb_data_request(dev, skb);
346 if (err != LAPB_OK) {
347 printk(KERN_ERR "x25_asy: lapb_data_request error - %d\n", err);
356 * LAPB interface boilerplate
360 * Called when I frame data arrives. We did the work above - throw it
364 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
366 return netif_rx(skb);
370 * Data has emerged from the LAPB protocol machine. We don't handle
371 * busy cases too well. Its tricky to see how to do this nicely -
372 * perhaps lapb should allow us to bounce this ?
375 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
377 struct x25_asy *sl = netdev_priv(dev);
379 spin_lock(&sl->lock);
380 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
381 spin_unlock(&sl->lock);
382 printk(KERN_ERR "x25_asy: tbusy drop\n");
386 /* We were not busy, so we are now... :-) */
389 dev->stats.tx_bytes += skb->len;
390 x25_asy_encaps(sl, skb->data, skb->len);
393 spin_unlock(&sl->lock);
397 * LAPB connection establish/down information.
400 static void x25_asy_connected(struct net_device *dev, int reason)
402 struct x25_asy *sl = netdev_priv(dev);
406 skb = dev_alloc_skb(1);
408 printk(KERN_ERR "x25_asy: out of memory\n");
412 ptr = skb_put(skb, 1);
415 skb->protocol = x25_type_trans(skb, sl->dev);
419 static void x25_asy_disconnected(struct net_device *dev, int reason)
421 struct x25_asy *sl = netdev_priv(dev);
425 skb = dev_alloc_skb(1);
427 printk(KERN_ERR "x25_asy: out of memory\n");
431 ptr = skb_put(skb, 1);
434 skb->protocol = x25_type_trans(skb, sl->dev);
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,
449 /* Open the low-level part of the X.25 channel. Easy! */
450 static int x25_asy_open(struct net_device *dev)
452 struct x25_asy *sl = netdev_priv(dev);
460 * Allocate the X.25 frame buffers:
462 * rbuff Receive buffer.
463 * xbuff Transmit buffer.
468 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
469 if (sl->rbuff == NULL)
471 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
472 if (sl->xbuff == NULL)
478 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
480 netif_start_queue(dev);
485 err = lapb_register(dev, &x25_asy_callbacks);
498 /* Close the low-level part of the X.25 channel. Easy! */
499 static int x25_asy_close(struct net_device *dev)
501 struct x25_asy *sl = netdev_priv(dev);
504 spin_lock(&sl->lock);
506 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
508 netif_stop_queue(dev);
511 err = lapb_unregister(dev);
513 printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",
515 spin_unlock(&sl->lock);
520 * Handle the 'receiver data ready' interrupt.
521 * This function is called by the 'tty_io' module in the kernel when
522 * a block of X.25 data has been received, which can now be decapsulated
523 * and sent on to some IP layer for further processing.
526 static void x25_asy_receive_buf(struct tty_struct *tty,
527 const unsigned char *cp, char *fp, int count)
529 struct x25_asy *sl = tty->disc_data;
531 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
535 /* Read the characters out of the buffer */
538 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
539 sl->dev->stats.rx_errors++;
543 x25_asy_unesc(sl, *cp++);
548 * Open the high-level part of the X.25 channel.
549 * This function is called by the TTY module when the
550 * X.25 line discipline is called for. Because we are
551 * sure the tty line exists, we only have to link it to
552 * a free X.25 channel...
555 static int x25_asy_open_tty(struct tty_struct *tty)
557 struct x25_asy *sl = tty->disc_data;
560 if (tty->ops->write == NULL)
563 /* First make sure we're not already connected. */
564 if (sl && sl->magic == X25_ASY_MAGIC)
567 /* OK. Find a free X.25 channel to use. */
568 sl = x25_asy_alloc();
574 tty->receive_room = 65536;
575 tty_driver_flush_buffer(tty);
576 tty_ldisc_flush(tty);
578 /* Restore default settings */
579 sl->dev->type = ARPHRD_X25;
581 /* Perform the low-level X.25 async init */
582 err = x25_asy_open(sl->dev);
585 /* Done. We have linked the TTY line to a channel. */
586 return sl->dev->base_addr;
591 * Close down an X.25 channel.
592 * This means flushing out any pending queues, and then restoring the
593 * TTY line discipline to what it was before it got hooked to X.25
594 * (which usually is TTY again).
596 static void x25_asy_close_tty(struct tty_struct *tty)
598 struct x25_asy *sl = tty->disc_data;
600 /* First make sure we're connected. */
601 if (!sl || sl->magic != X25_ASY_MAGIC)
605 if (sl->dev->flags & IFF_UP)
609 tty->disc_data = NULL;
614 /************************************************************************
615 * STANDARD X.25 ENCAPSULATION *
616 ************************************************************************/
618 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
620 unsigned char *ptr = d;
624 * Send an initial END character to flush out any
625 * data that may have accumulated in the receiver
629 *ptr++ = X25_END; /* Send 10111110 bit seq */
632 * For each byte in the packet, send the appropriate
633 * character sequence, according to the X.25 protocol.
640 *ptr++ = X25_ESCAPE(X25_END);
644 *ptr++ = X25_ESCAPE(X25_ESC);
655 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
660 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
663 clear_bit(SLF_ESCAPE, &sl->flags);
667 set_bit(SLF_ESCAPE, &sl->flags);
669 case X25_ESCAPE(X25_ESC):
670 case X25_ESCAPE(X25_END):
671 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
675 if (!test_bit(SLF_ERROR, &sl->flags)) {
676 if (sl->rcount < sl->buffsize) {
677 sl->rbuff[sl->rcount++] = s;
680 sl->dev->stats.rx_over_errors++;
681 set_bit(SLF_ERROR, &sl->flags);
686 /* Perform I/O control on an active X.25 channel. */
687 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
688 unsigned int cmd, unsigned long arg)
690 struct x25_asy *sl = tty->disc_data;
692 /* First make sure we're connected. */
693 if (!sl || sl->magic != X25_ASY_MAGIC)
698 if (copy_to_user((void __user *)arg, sl->dev->name,
699 strlen(sl->dev->name) + 1))
705 return tty_mode_ioctl(tty, file, cmd, arg);
710 static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
711 unsigned int cmd, unsigned long arg)
716 return x25_asy_ioctl(tty, file, cmd,
717 (unsigned long)compat_ptr(arg));
724 static int x25_asy_open_dev(struct net_device *dev)
726 struct x25_asy *sl = netdev_priv(dev);
732 static const struct net_device_ops x25_asy_netdev_ops = {
733 .ndo_open = x25_asy_open_dev,
734 .ndo_stop = x25_asy_close,
735 .ndo_start_xmit = x25_asy_xmit,
736 .ndo_tx_timeout = x25_asy_timeout,
737 .ndo_change_mtu = x25_asy_change_mtu,
740 /* Initialise the X.25 driver. Called by the device init code */
741 static void x25_asy_setup(struct net_device *dev)
743 struct x25_asy *sl = netdev_priv(dev);
745 sl->magic = X25_ASY_MAGIC;
747 spin_lock_init(&sl->lock);
748 set_bit(SLF_INUSE, &sl->flags);
751 * Finish setting up the DEVICE info.
755 dev->netdev_ops = &x25_asy_netdev_ops;
756 dev->watchdog_timeo = HZ*20;
757 dev->hard_header_len = 0;
759 dev->type = ARPHRD_X25;
760 dev->tx_queue_len = 10;
762 /* New-style flags. */
763 dev->flags = IFF_NOARP;
766 static struct tty_ldisc_ops x25_ldisc = {
767 .owner = THIS_MODULE,
768 .magic = TTY_LDISC_MAGIC,
770 .open = x25_asy_open_tty,
771 .close = x25_asy_close_tty,
772 .ioctl = x25_asy_ioctl,
774 .compat_ioctl = x25_asy_compat_ioctl,
776 .receive_buf = x25_asy_receive_buf,
777 .write_wakeup = x25_asy_write_wakeup,
780 static int __init init_x25_asy(void)
782 if (x25_asy_maxdev < 4)
783 x25_asy_maxdev = 4; /* Sanity */
785 printk(KERN_INFO "X.25 async: version 0.00 ALPHA "
786 "(dynamic channels, max=%d).\n", x25_asy_maxdev);
788 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
791 printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] "
792 "array! Uaargh! (-> No X.25 available)\n");
796 return tty_register_ldisc(N_X25, &x25_ldisc);
800 static void __exit exit_x25_asy(void)
802 struct net_device *dev;
805 for (i = 0; i < x25_asy_maxdev; i++) {
806 dev = x25_asy_devs[i];
808 struct x25_asy *sl = netdev_priv(dev);
810 spin_lock_bh(&sl->lock);
814 spin_unlock_bh(&sl->lock);
816 * VSV = if dev->start==0, then device
817 * unregistered while close proc.
819 unregister_netdev(dev);
825 tty_unregister_ldisc(N_X25);
828 module_init(init_x25_asy);
829 module_exit(exit_x25_asy);