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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 #include <linux/module.h>
21 #include <linux/uaccess.h>
22 #include <linux/bitops.h>
23 #include <linux/string.h>
25 #include <linux/interrupt.h>
27 #include <linux/tty.h>
28 #include <linux/errno.h>
29 #include <linux/netdevice.h>
30 #include <linux/etherdevice.h>
31 #include <linux/skbuff.h>
32 #include <linux/if_arp.h>
33 #include <linux/lapb.h>
34 #include <linux/init.h>
35 #include <linux/rtnetlink.h>
36 #include <linux/compat.h>
37 #include <linux/slab.h>
38 #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), name,
85 NET_NAME_UNKNOWN, x25_asy_setup);
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 pr_warn("%s(): register_netdev() failure\n", __func__);
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 netdev_err(sl->dev, "x25_asy_free for already free unit\n");
121 static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
123 struct x25_asy *sl = netdev_priv(dev);
124 unsigned char *xbuff, *rbuff;
128 xbuff = kmalloc(len + 4, GFP_ATOMIC);
129 rbuff = kmalloc(len + 4, GFP_ATOMIC);
131 if (xbuff == NULL || rbuff == NULL) {
137 spin_lock_bh(&sl->lock);
138 xbuff = xchg(&sl->xbuff, xbuff);
140 if (sl->xleft <= len) {
141 memcpy(sl->xbuff, sl->xhead, sl->xleft);
144 dev->stats.tx_dropped++;
147 sl->xhead = sl->xbuff;
149 rbuff = xchg(&sl->rbuff, rbuff);
151 if (sl->rcount <= len) {
152 memcpy(sl->rbuff, rbuff, sl->rcount);
155 dev->stats.rx_over_errors++;
156 set_bit(SLF_ERROR, &sl->flags);
163 spin_unlock_bh(&sl->lock);
171 /* Set the "sending" flag. This must be atomic, hence the ASM. */
173 static inline void x25_asy_lock(struct x25_asy *sl)
175 netif_stop_queue(sl->dev);
179 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
181 static inline void x25_asy_unlock(struct x25_asy *sl)
183 netif_wake_queue(sl->dev);
186 /* Send an LAPB frame to the LAPB module to process. */
188 static void x25_asy_bump(struct x25_asy *sl)
190 struct net_device *dev = sl->dev;
196 dev->stats.rx_bytes += count;
198 skb = dev_alloc_skb(count);
200 netdev_warn(sl->dev, "memory squeeze, dropping packet\n");
201 dev->stats.rx_dropped++;
204 skb_put_data(skb, sl->rbuff, count);
205 skb->protocol = x25_type_trans(skb, sl->dev);
206 err = lapb_data_received(skb->dev, skb);
207 if (err != LAPB_OK) {
209 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
211 dev->stats.rx_packets++;
215 /* Encapsulate one IP datagram and stuff into a TTY queue. */
216 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
219 int actual, count, mtu = sl->dev->mtu;
222 /* Sigh, shouldn't occur BUT ... */
224 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
226 sl->dev->stats.tx_dropped++;
232 count = x25_asy_esc(p, sl->xbuff, len);
234 /* Order of next two lines is *very* important.
235 * When we are sending a little amount of data,
236 * the transfer may be completed inside driver.write()
237 * routine, because it's running with interrupts enabled.
238 * In this case we *never* got WRITE_WAKEUP event,
239 * if we did not request it before write operation.
240 * 14 Oct 1994 Dmitry Gorodchanin.
242 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
243 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
244 sl->xleft = count - actual;
245 sl->xhead = sl->xbuff + actual;
247 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
251 * Called by the driver when there's room for more data. If we have
252 * more packets to send, we send them here.
254 static void x25_asy_write_wakeup(struct tty_struct *tty)
257 struct x25_asy *sl = tty->disc_data;
259 /* First make sure we're connected. */
260 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
263 if (sl->xleft <= 0) {
264 /* Now serial buffer is almost free & we can start
265 * transmission of another packet */
266 sl->dev->stats.tx_packets++;
267 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
272 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
277 static void x25_asy_timeout(struct net_device *dev)
279 struct x25_asy *sl = netdev_priv(dev);
281 spin_lock(&sl->lock);
282 if (netif_queue_stopped(dev)) {
283 /* May be we must check transmitter timeout here ?
284 * 14 Oct 1994 Dmitry Gorodchanin.
286 netdev_warn(dev, "transmit timed out, %s?\n",
287 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
288 "bad line quality" : "driver error");
290 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
293 spin_unlock(&sl->lock);
296 /* Encapsulate an IP datagram and kick it into a TTY queue. */
298 static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
299 struct net_device *dev)
301 struct x25_asy *sl = netdev_priv(dev);
304 if (!netif_running(sl->dev)) {
305 netdev_err(dev, "xmit call when iface is down\n");
310 switch (skb->data[0]) {
313 case X25_IFACE_CONNECT: /* Connection request .. do nothing */
314 err = lapb_connect_request(dev);
316 netdev_err(dev, "lapb_connect_request error: %d\n",
320 case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
321 err = lapb_disconnect_request(dev);
323 netdev_err(dev, "lapb_disconnect_request error: %d\n",
329 skb_pull(skb, 1); /* Remove control byte */
331 * If we are busy already- too bad. We ought to be able
332 * to queue things at this point, to allow for a little
333 * frame buffer. Oh well...
334 * -----------------------------------------------------
335 * I hate queues in X.25 driver. May be it's efficient,
336 * but for me latency is more important. ;)
338 * 14 Oct 1994 Dmitry Gorodchanin.
341 err = lapb_data_request(dev, skb);
342 if (err != LAPB_OK) {
343 netdev_err(dev, "lapb_data_request error: %d\n", err);
352 * LAPB interface boilerplate
356 * Called when I frame data arrive. We add a pseudo header for upper
357 * layers and pass it to upper layers.
360 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
362 if (skb_cow(skb, 1)) {
367 skb->data[0] = X25_IFACE_DATA;
369 skb->protocol = x25_type_trans(skb, dev);
371 return netif_rx(skb);
375 * Data has emerged from the LAPB protocol machine. We don't handle
376 * busy cases too well. Its tricky to see how to do this nicely -
377 * perhaps lapb should allow us to bounce this ?
380 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
382 struct x25_asy *sl = netdev_priv(dev);
384 spin_lock(&sl->lock);
385 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
386 spin_unlock(&sl->lock);
387 netdev_err(dev, "tbusy drop\n");
391 /* We were not busy, so we are now... :-) */
394 dev->stats.tx_bytes += skb->len;
395 x25_asy_encaps(sl, skb->data, skb->len);
398 spin_unlock(&sl->lock);
402 * LAPB connection establish/down information.
405 static void x25_asy_connected(struct net_device *dev, int reason)
407 struct x25_asy *sl = netdev_priv(dev);
411 skb = dev_alloc_skb(1);
413 netdev_err(dev, "out of memory\n");
417 ptr = skb_put(skb, 1);
418 *ptr = X25_IFACE_CONNECT;
420 skb->protocol = x25_type_trans(skb, sl->dev);
424 static void x25_asy_disconnected(struct net_device *dev, int reason)
426 struct x25_asy *sl = netdev_priv(dev);
430 skb = dev_alloc_skb(1);
432 netdev_err(dev, "out of memory\n");
436 ptr = skb_put(skb, 1);
437 *ptr = X25_IFACE_DISCONNECT;
439 skb->protocol = x25_type_trans(skb, sl->dev);
443 static const struct lapb_register_struct x25_asy_callbacks = {
444 .connect_confirmation = x25_asy_connected,
445 .connect_indication = x25_asy_connected,
446 .disconnect_confirmation = x25_asy_disconnected,
447 .disconnect_indication = x25_asy_disconnected,
448 .data_indication = x25_asy_data_indication,
449 .data_transmit = x25_asy_data_transmit,
453 /* Open the low-level part of the X.25 channel. Easy! */
454 static int x25_asy_open(struct net_device *dev)
456 struct x25_asy *sl = netdev_priv(dev);
464 * Allocate the X.25 frame buffers:
466 * rbuff Receive buffer.
467 * xbuff Transmit buffer.
472 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
473 if (sl->rbuff == NULL)
475 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
476 if (sl->xbuff == NULL)
482 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
484 netif_start_queue(dev);
489 err = lapb_register(dev, &x25_asy_callbacks);
504 /* Close the low-level part of the X.25 channel. Easy! */
505 static int x25_asy_close(struct net_device *dev)
507 struct x25_asy *sl = netdev_priv(dev);
509 spin_lock(&sl->lock);
511 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
513 netif_stop_queue(dev);
516 spin_unlock(&sl->lock);
521 * Handle the 'receiver data ready' interrupt.
522 * This function is called by the 'tty_io' module in the kernel when
523 * a block of X.25 data has been received, which can now be decapsulated
524 * and sent on to some IP layer for further processing.
527 static void x25_asy_receive_buf(struct tty_struct *tty,
528 const unsigned char *cp, char *fp, int count)
530 struct x25_asy *sl = tty->disc_data;
532 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
536 /* Read the characters out of the buffer */
539 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
540 sl->dev->stats.rx_errors++;
544 x25_asy_unesc(sl, *cp++);
549 * Open the high-level part of the X.25 channel.
550 * This function is called by the TTY module when the
551 * X.25 line discipline is called for. Because we are
552 * sure the tty line exists, we only have to link it to
553 * a free X.25 channel...
556 static int x25_asy_open_tty(struct tty_struct *tty)
561 if (tty->ops->write == NULL)
564 /* OK. Find a free X.25 channel to use. */
565 sl = x25_asy_alloc();
571 tty->receive_room = 65536;
572 tty_driver_flush_buffer(tty);
573 tty_ldisc_flush(tty);
575 /* Restore default settings */
576 sl->dev->type = ARPHRD_X25;
578 /* Perform the low-level X.25 async init */
579 err = x25_asy_open(sl->dev);
584 /* Done. We have linked the TTY line to a channel. */
590 * Close down an X.25 channel.
591 * This means flushing out any pending queues, and then restoring the
592 * TTY line discipline to what it was before it got hooked to X.25
593 * (which usually is TTY again).
595 static void x25_asy_close_tty(struct tty_struct *tty)
597 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 err = lapb_unregister(sl->dev);
611 pr_err("x25_asy_close: lapb_unregister error: %d\n",
614 tty->disc_data = NULL;
619 /************************************************************************
620 * STANDARD X.25 ENCAPSULATION *
621 ************************************************************************/
623 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
625 unsigned char *ptr = d;
629 * Send an initial END character to flush out any
630 * data that may have accumulated in the receiver
634 *ptr++ = X25_END; /* Send 10111110 bit seq */
637 * For each byte in the packet, send the appropriate
638 * character sequence, according to the X.25 protocol.
645 *ptr++ = X25_ESCAPE(X25_END);
649 *ptr++ = X25_ESCAPE(X25_ESC);
660 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
665 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
668 clear_bit(SLF_ESCAPE, &sl->flags);
672 set_bit(SLF_ESCAPE, &sl->flags);
674 case X25_ESCAPE(X25_ESC):
675 case X25_ESCAPE(X25_END):
676 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
680 if (!test_bit(SLF_ERROR, &sl->flags)) {
681 if (sl->rcount < sl->buffsize) {
682 sl->rbuff[sl->rcount++] = s;
685 sl->dev->stats.rx_over_errors++;
686 set_bit(SLF_ERROR, &sl->flags);
691 /* Perform I/O control on an active X.25 channel. */
692 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
693 unsigned int cmd, unsigned long arg)
695 struct x25_asy *sl = tty->disc_data;
697 /* First make sure we're connected. */
698 if (!sl || sl->magic != X25_ASY_MAGIC)
703 if (copy_to_user((void __user *)arg, sl->dev->name,
704 strlen(sl->dev->name) + 1))
710 return tty_mode_ioctl(tty, file, cmd, arg);
715 static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
716 unsigned int cmd, unsigned long arg)
721 return x25_asy_ioctl(tty, file, cmd,
722 (unsigned long)compat_ptr(arg));
729 static int x25_asy_open_dev(struct net_device *dev)
731 struct x25_asy *sl = netdev_priv(dev);
737 static const struct net_device_ops x25_asy_netdev_ops = {
738 .ndo_open = x25_asy_open_dev,
739 .ndo_stop = x25_asy_close,
740 .ndo_start_xmit = x25_asy_xmit,
741 .ndo_tx_timeout = x25_asy_timeout,
742 .ndo_change_mtu = x25_asy_change_mtu,
745 /* Initialise the X.25 driver. Called by the device init code */
746 static void x25_asy_setup(struct net_device *dev)
748 struct x25_asy *sl = netdev_priv(dev);
750 sl->magic = X25_ASY_MAGIC;
752 spin_lock_init(&sl->lock);
753 set_bit(SLF_INUSE, &sl->flags);
756 * Finish setting up the DEVICE info.
761 dev->max_mtu = 65534;
762 dev->netdev_ops = &x25_asy_netdev_ops;
763 dev->watchdog_timeo = HZ*20;
764 dev->hard_header_len = 0;
766 dev->type = ARPHRD_X25;
767 dev->tx_queue_len = 10;
769 /* New-style flags. */
770 dev->flags = IFF_NOARP;
773 static struct tty_ldisc_ops x25_ldisc = {
774 .owner = THIS_MODULE,
775 .magic = TTY_LDISC_MAGIC,
777 .open = x25_asy_open_tty,
778 .close = x25_asy_close_tty,
779 .ioctl = x25_asy_ioctl,
781 .compat_ioctl = x25_asy_compat_ioctl,
783 .receive_buf = x25_asy_receive_buf,
784 .write_wakeup = x25_asy_write_wakeup,
787 static int __init init_x25_asy(void)
789 if (x25_asy_maxdev < 4)
790 x25_asy_maxdev = 4; /* Sanity */
792 pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n",
795 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
800 return tty_register_ldisc(N_X25, &x25_ldisc);
804 static void __exit exit_x25_asy(void)
806 struct net_device *dev;
809 for (i = 0; i < x25_asy_maxdev; i++) {
810 dev = x25_asy_devs[i];
812 struct x25_asy *sl = netdev_priv(dev);
814 spin_lock_bh(&sl->lock);
818 spin_unlock_bh(&sl->lock);
820 * VSV = if dev->start==0, then device
821 * unregistered while close proc.
823 unregister_netdev(dev);
829 tty_unregister_ldisc(N_X25);
832 module_init(init_x25_asy);
833 module_exit(exit_x25_asy);