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),
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;
125 int len = 2 * newmtu;
127 xbuff = kmalloc(len + 4, GFP_ATOMIC);
128 rbuff = kmalloc(len + 4, GFP_ATOMIC);
130 if (xbuff == NULL || rbuff == NULL) {
136 spin_lock_bh(&sl->lock);
137 xbuff = xchg(&sl->xbuff, xbuff);
139 if (sl->xleft <= len) {
140 memcpy(sl->xbuff, sl->xhead, sl->xleft);
143 dev->stats.tx_dropped++;
146 sl->xhead = sl->xbuff;
148 rbuff = xchg(&sl->rbuff, rbuff);
150 if (sl->rcount <= len) {
151 memcpy(sl->rbuff, rbuff, sl->rcount);
154 dev->stats.rx_over_errors++;
155 set_bit(SLF_ERROR, &sl->flags);
162 spin_unlock_bh(&sl->lock);
170 /* Set the "sending" flag. This must be atomic, hence the ASM. */
172 static inline void x25_asy_lock(struct x25_asy *sl)
174 netif_stop_queue(sl->dev);
178 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
180 static inline void x25_asy_unlock(struct x25_asy *sl)
182 netif_wake_queue(sl->dev);
185 /* Send one completely decapsulated IP datagram to the IP layer. */
187 static void x25_asy_bump(struct x25_asy *sl)
189 struct net_device *dev = sl->dev;
195 dev->stats.rx_bytes += count;
197 skb = dev_alloc_skb(count+1);
199 netdev_warn(sl->dev, "memory squeeze, dropping packet\n");
200 dev->stats.rx_dropped++;
203 skb_push(skb, 1); /* LAPB internal control */
204 memcpy(skb_put(skb, count), 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);
212 dev->stats.rx_packets++;
216 /* Encapsulate one IP datagram and stuff into a TTY queue. */
217 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
220 int actual, count, mtu = sl->dev->mtu;
223 /* Sigh, shouldn't occur BUT ... */
225 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
227 sl->dev->stats.tx_dropped++;
233 count = x25_asy_esc(p, sl->xbuff, len);
235 /* Order of next two lines is *very* important.
236 * When we are sending a little amount of data,
237 * the transfer may be completed inside driver.write()
238 * routine, because it's running with interrupts enabled.
239 * In this case we *never* got WRITE_WAKEUP event,
240 * if we did not request it before write operation.
241 * 14 Oct 1994 Dmitry Gorodchanin.
243 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
244 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
245 sl->xleft = count - actual;
246 sl->xhead = sl->xbuff + actual;
248 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
252 * Called by the driver when there's room for more data. If we have
253 * more packets to send, we send them here.
255 static void x25_asy_write_wakeup(struct tty_struct *tty)
258 struct x25_asy *sl = tty->disc_data;
260 /* First make sure we're connected. */
261 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
264 if (sl->xleft <= 0) {
265 /* Now serial buffer is almost free & we can start
266 * transmission of another packet */
267 sl->dev->stats.tx_packets++;
268 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
273 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
278 static void x25_asy_timeout(struct net_device *dev)
280 struct x25_asy *sl = netdev_priv(dev);
282 spin_lock(&sl->lock);
283 if (netif_queue_stopped(dev)) {
284 /* May be we must check transmitter timeout here ?
285 * 14 Oct 1994 Dmitry Gorodchanin.
287 netdev_warn(dev, "transmit timed out, %s?\n",
288 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
289 "bad line quality" : "driver error");
291 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
294 spin_unlock(&sl->lock);
297 /* Encapsulate an IP datagram and kick it into a TTY queue. */
299 static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
300 struct net_device *dev)
302 struct x25_asy *sl = netdev_priv(dev);
305 if (!netif_running(sl->dev)) {
306 netdev_err(dev, "xmit call when iface is down\n");
311 switch (skb->data[0]) {
314 case X25_IFACE_CONNECT: /* Connection request .. do nothing */
315 err = lapb_connect_request(dev);
317 netdev_err(dev, "lapb_connect_request error: %d\n",
321 case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
322 err = lapb_disconnect_request(dev);
324 netdev_err(dev, "lapb_disconnect_request error: %d\n",
330 skb_pull(skb, 1); /* Remove control byte */
332 * If we are busy already- too bad. We ought to be able
333 * to queue things at this point, to allow for a little
334 * frame buffer. Oh well...
335 * -----------------------------------------------------
336 * I hate queues in X.25 driver. May be it's efficient,
337 * but for me latency is more important. ;)
339 * 14 Oct 1994 Dmitry Gorodchanin.
342 err = lapb_data_request(dev, skb);
343 if (err != LAPB_OK) {
344 netdev_err(dev, "lapb_data_request error: %d\n", err);
353 * LAPB interface boilerplate
357 * Called when I frame data arrives. We did the work above - throw it
361 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
363 return netif_rx(skb);
367 * Data has emerged from the LAPB protocol machine. We don't handle
368 * busy cases too well. Its tricky to see how to do this nicely -
369 * perhaps lapb should allow us to bounce this ?
372 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
374 struct x25_asy *sl = netdev_priv(dev);
376 spin_lock(&sl->lock);
377 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
378 spin_unlock(&sl->lock);
379 netdev_err(dev, "tbusy drop\n");
383 /* We were not busy, so we are now... :-) */
386 dev->stats.tx_bytes += skb->len;
387 x25_asy_encaps(sl, skb->data, skb->len);
390 spin_unlock(&sl->lock);
394 * LAPB connection establish/down information.
397 static void x25_asy_connected(struct net_device *dev, int reason)
399 struct x25_asy *sl = netdev_priv(dev);
403 skb = dev_alloc_skb(1);
405 netdev_err(dev, "out of memory\n");
409 ptr = skb_put(skb, 1);
410 *ptr = X25_IFACE_CONNECT;
412 skb->protocol = x25_type_trans(skb, sl->dev);
416 static void x25_asy_disconnected(struct net_device *dev, int reason)
418 struct x25_asy *sl = netdev_priv(dev);
422 skb = dev_alloc_skb(1);
424 netdev_err(dev, "out of memory\n");
428 ptr = skb_put(skb, 1);
429 *ptr = X25_IFACE_DISCONNECT;
431 skb->protocol = x25_type_trans(skb, sl->dev);
435 static const struct lapb_register_struct x25_asy_callbacks = {
436 .connect_confirmation = x25_asy_connected,
437 .connect_indication = x25_asy_connected,
438 .disconnect_confirmation = x25_asy_disconnected,
439 .disconnect_indication = x25_asy_disconnected,
440 .data_indication = x25_asy_data_indication,
441 .data_transmit = x25_asy_data_transmit,
445 /* Open the low-level part of the X.25 channel. Easy! */
446 static int x25_asy_open(struct net_device *dev)
448 struct x25_asy *sl = netdev_priv(dev);
456 * Allocate the X.25 frame buffers:
458 * rbuff Receive buffer.
459 * xbuff Transmit buffer.
464 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
465 if (sl->rbuff == NULL)
467 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
468 if (sl->xbuff == NULL)
474 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
476 netif_start_queue(dev);
481 err = lapb_register(dev, &x25_asy_callbacks);
494 /* Close the low-level part of the X.25 channel. Easy! */
495 static int x25_asy_close(struct net_device *dev)
497 struct x25_asy *sl = netdev_priv(dev);
499 spin_lock(&sl->lock);
501 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
503 netif_stop_queue(dev);
506 spin_unlock(&sl->lock);
511 * Handle the 'receiver data ready' interrupt.
512 * This function is called by the 'tty_io' module in the kernel when
513 * a block of X.25 data has been received, which can now be decapsulated
514 * and sent on to some IP layer for further processing.
517 static void x25_asy_receive_buf(struct tty_struct *tty,
518 const unsigned char *cp, char *fp, int count)
520 struct x25_asy *sl = tty->disc_data;
522 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
526 /* Read the characters out of the buffer */
529 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
530 sl->dev->stats.rx_errors++;
534 x25_asy_unesc(sl, *cp++);
539 * Open the high-level part of the X.25 channel.
540 * This function is called by the TTY module when the
541 * X.25 line discipline is called for. Because we are
542 * sure the tty line exists, we only have to link it to
543 * a free X.25 channel...
546 static int x25_asy_open_tty(struct tty_struct *tty)
548 struct x25_asy *sl = tty->disc_data;
551 if (tty->ops->write == NULL)
554 /* First make sure we're not already connected. */
555 if (sl && sl->magic == X25_ASY_MAGIC)
558 /* OK. Find a free X.25 channel to use. */
559 sl = x25_asy_alloc();
565 tty->receive_room = 65536;
566 tty_driver_flush_buffer(tty);
567 tty_ldisc_flush(tty);
569 /* Restore default settings */
570 sl->dev->type = ARPHRD_X25;
572 /* Perform the low-level X.25 async init */
573 err = x25_asy_open(sl->dev);
576 /* Done. We have linked the TTY line to a channel. */
582 * Close down an X.25 channel.
583 * This means flushing out any pending queues, and then restoring the
584 * TTY line discipline to what it was before it got hooked to X.25
585 * (which usually is TTY again).
587 static void x25_asy_close_tty(struct tty_struct *tty)
589 struct x25_asy *sl = tty->disc_data;
592 /* First make sure we're connected. */
593 if (!sl || sl->magic != X25_ASY_MAGIC)
597 if (sl->dev->flags & IFF_UP)
601 err = lapb_unregister(sl->dev);
603 pr_err("x25_asy_close: lapb_unregister error: %d\n",
606 tty->disc_data = NULL;
611 /************************************************************************
612 * STANDARD X.25 ENCAPSULATION *
613 ************************************************************************/
615 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
617 unsigned char *ptr = d;
621 * Send an initial END character to flush out any
622 * data that may have accumulated in the receiver
626 *ptr++ = X25_END; /* Send 10111110 bit seq */
629 * For each byte in the packet, send the appropriate
630 * character sequence, according to the X.25 protocol.
637 *ptr++ = X25_ESCAPE(X25_END);
641 *ptr++ = X25_ESCAPE(X25_ESC);
652 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
657 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
660 clear_bit(SLF_ESCAPE, &sl->flags);
664 set_bit(SLF_ESCAPE, &sl->flags);
666 case X25_ESCAPE(X25_ESC):
667 case X25_ESCAPE(X25_END):
668 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
672 if (!test_bit(SLF_ERROR, &sl->flags)) {
673 if (sl->rcount < sl->buffsize) {
674 sl->rbuff[sl->rcount++] = s;
677 sl->dev->stats.rx_over_errors++;
678 set_bit(SLF_ERROR, &sl->flags);
683 /* Perform I/O control on an active X.25 channel. */
684 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
685 unsigned int cmd, unsigned long arg)
687 struct x25_asy *sl = tty->disc_data;
689 /* First make sure we're connected. */
690 if (!sl || sl->magic != X25_ASY_MAGIC)
695 if (copy_to_user((void __user *)arg, sl->dev->name,
696 strlen(sl->dev->name) + 1))
702 return tty_mode_ioctl(tty, file, cmd, arg);
707 static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
708 unsigned int cmd, unsigned long arg)
713 return x25_asy_ioctl(tty, file, cmd,
714 (unsigned long)compat_ptr(arg));
721 static int x25_asy_open_dev(struct net_device *dev)
723 struct x25_asy *sl = netdev_priv(dev);
729 static const struct net_device_ops x25_asy_netdev_ops = {
730 .ndo_open = x25_asy_open_dev,
731 .ndo_stop = x25_asy_close,
732 .ndo_start_xmit = x25_asy_xmit,
733 .ndo_tx_timeout = x25_asy_timeout,
734 .ndo_change_mtu = x25_asy_change_mtu,
737 /* Initialise the X.25 driver. Called by the device init code */
738 static void x25_asy_setup(struct net_device *dev)
740 struct x25_asy *sl = netdev_priv(dev);
742 sl->magic = X25_ASY_MAGIC;
744 spin_lock_init(&sl->lock);
745 set_bit(SLF_INUSE, &sl->flags);
748 * Finish setting up the DEVICE info.
752 dev->netdev_ops = &x25_asy_netdev_ops;
753 dev->watchdog_timeo = HZ*20;
754 dev->hard_header_len = 0;
756 dev->type = ARPHRD_X25;
757 dev->tx_queue_len = 10;
759 /* New-style flags. */
760 dev->flags = IFF_NOARP;
763 static struct tty_ldisc_ops x25_ldisc = {
764 .owner = THIS_MODULE,
765 .magic = TTY_LDISC_MAGIC,
767 .open = x25_asy_open_tty,
768 .close = x25_asy_close_tty,
769 .ioctl = x25_asy_ioctl,
771 .compat_ioctl = x25_asy_compat_ioctl,
773 .receive_buf = x25_asy_receive_buf,
774 .write_wakeup = x25_asy_write_wakeup,
777 static int __init init_x25_asy(void)
779 if (x25_asy_maxdev < 4)
780 x25_asy_maxdev = 4; /* Sanity */
782 pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n",
785 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
790 return tty_register_ldisc(N_X25, &x25_ldisc);
794 static void __exit exit_x25_asy(void)
796 struct net_device *dev;
799 for (i = 0; i < x25_asy_maxdev; i++) {
800 dev = x25_asy_devs[i];
802 struct x25_asy *sl = netdev_priv(dev);
804 spin_lock_bh(&sl->lock);
808 spin_unlock_bh(&sl->lock);
810 * VSV = if dev->start==0, then device
811 * unregistered while close proc.
813 unregister_netdev(dev);
819 tty_unregister_ldisc(N_X25);
822 module_init(init_x25_asy);
823 module_exit(exit_x25_asy);