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;
131 xbuff = kmalloc(len + 4, GFP_ATOMIC);
132 rbuff = kmalloc(len + 4, GFP_ATOMIC);
134 if (xbuff == NULL || rbuff == NULL) {
140 spin_lock_bh(&sl->lock);
141 xbuff = xchg(&sl->xbuff, xbuff);
143 if (sl->xleft <= len) {
144 memcpy(sl->xbuff, sl->xhead, sl->xleft);
147 dev->stats.tx_dropped++;
150 sl->xhead = sl->xbuff;
152 rbuff = xchg(&sl->rbuff, rbuff);
154 if (sl->rcount <= len) {
155 memcpy(sl->rbuff, rbuff, sl->rcount);
158 dev->stats.rx_over_errors++;
159 set_bit(SLF_ERROR, &sl->flags);
166 spin_unlock_bh(&sl->lock);
174 /* Set the "sending" flag. This must be atomic, hence the ASM. */
176 static inline void x25_asy_lock(struct x25_asy *sl)
178 netif_stop_queue(sl->dev);
182 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
184 static inline void x25_asy_unlock(struct x25_asy *sl)
186 netif_wake_queue(sl->dev);
189 /* Send an LAPB frame to the LAPB module to process. */
191 static void x25_asy_bump(struct x25_asy *sl)
193 struct net_device *dev = sl->dev;
199 dev->stats.rx_bytes += count;
201 skb = dev_alloc_skb(count);
203 netdev_warn(sl->dev, "memory squeeze, dropping packet\n");
204 dev->stats.rx_dropped++;
207 memcpy(skb_put(skb, count), sl->rbuff, count);
208 skb->protocol = x25_type_trans(skb, sl->dev);
209 err = lapb_data_received(skb->dev, skb);
210 if (err != LAPB_OK) {
212 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
214 dev->stats.rx_packets++;
218 /* Encapsulate one IP datagram and stuff into a TTY queue. */
219 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
222 int actual, count, mtu = sl->dev->mtu;
225 /* Sigh, shouldn't occur BUT ... */
227 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
229 sl->dev->stats.tx_dropped++;
235 count = x25_asy_esc(p, sl->xbuff, len);
237 /* Order of next two lines is *very* important.
238 * When we are sending a little amount of data,
239 * the transfer may be completed inside driver.write()
240 * routine, because it's running with interrupts enabled.
241 * In this case we *never* got WRITE_WAKEUP event,
242 * if we did not request it before write operation.
243 * 14 Oct 1994 Dmitry Gorodchanin.
245 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
246 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
247 sl->xleft = count - actual;
248 sl->xhead = sl->xbuff + actual;
250 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
254 * Called by the driver when there's room for more data. If we have
255 * more packets to send, we send them here.
257 static void x25_asy_write_wakeup(struct tty_struct *tty)
260 struct x25_asy *sl = tty->disc_data;
262 /* First make sure we're connected. */
263 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
266 if (sl->xleft <= 0) {
267 /* Now serial buffer is almost free & we can start
268 * transmission of another packet */
269 sl->dev->stats.tx_packets++;
270 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
275 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
280 static void x25_asy_timeout(struct net_device *dev)
282 struct x25_asy *sl = netdev_priv(dev);
284 spin_lock(&sl->lock);
285 if (netif_queue_stopped(dev)) {
286 /* May be we must check transmitter timeout here ?
287 * 14 Oct 1994 Dmitry Gorodchanin.
289 netdev_warn(dev, "transmit timed out, %s?\n",
290 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
291 "bad line quality" : "driver error");
293 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
296 spin_unlock(&sl->lock);
299 /* Encapsulate an IP datagram and kick it into a TTY queue. */
301 static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
302 struct net_device *dev)
304 struct x25_asy *sl = netdev_priv(dev);
307 if (!netif_running(sl->dev)) {
308 netdev_err(dev, "xmit call when iface is down\n");
313 switch (skb->data[0]) {
316 case X25_IFACE_CONNECT: /* Connection request .. do nothing */
317 err = lapb_connect_request(dev);
319 netdev_err(dev, "lapb_connect_request error: %d\n",
323 case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
324 err = lapb_disconnect_request(dev);
326 netdev_err(dev, "lapb_disconnect_request error: %d\n",
332 skb_pull(skb, 1); /* Remove control byte */
334 * If we are busy already- too bad. We ought to be able
335 * to queue things at this point, to allow for a little
336 * frame buffer. Oh well...
337 * -----------------------------------------------------
338 * I hate queues in X.25 driver. May be it's efficient,
339 * but for me latency is more important. ;)
341 * 14 Oct 1994 Dmitry Gorodchanin.
344 err = lapb_data_request(dev, skb);
345 if (err != LAPB_OK) {
346 netdev_err(dev, "lapb_data_request error: %d\n", err);
355 * LAPB interface boilerplate
359 * Called when I frame data arrive. We add a pseudo header for upper
360 * layers and pass it to upper layers.
363 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
365 if (skb_cow(skb, 1)) {
370 skb->data[0] = X25_IFACE_DATA;
372 skb->protocol = x25_type_trans(skb, dev);
374 return netif_rx(skb);
378 * Data has emerged from the LAPB protocol machine. We don't handle
379 * busy cases too well. Its tricky to see how to do this nicely -
380 * perhaps lapb should allow us to bounce this ?
383 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
385 struct x25_asy *sl = netdev_priv(dev);
387 spin_lock(&sl->lock);
388 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
389 spin_unlock(&sl->lock);
390 netdev_err(dev, "tbusy drop\n");
394 /* We were not busy, so we are now... :-) */
397 dev->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 = netdev_priv(dev);
414 skb = dev_alloc_skb(1);
416 netdev_err(dev, "out of memory\n");
420 ptr = skb_put(skb, 1);
421 *ptr = X25_IFACE_CONNECT;
423 skb->protocol = x25_type_trans(skb, sl->dev);
427 static void x25_asy_disconnected(struct net_device *dev, int reason)
429 struct x25_asy *sl = netdev_priv(dev);
433 skb = dev_alloc_skb(1);
435 netdev_err(dev, "out of memory\n");
439 ptr = skb_put(skb, 1);
440 *ptr = X25_IFACE_DISCONNECT;
442 skb->protocol = x25_type_trans(skb, sl->dev);
446 static const 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,
456 /* Open the low-level part of the X.25 channel. Easy! */
457 static int x25_asy_open(struct net_device *dev)
459 struct x25_asy *sl = netdev_priv(dev);
467 * Allocate the X.25 frame buffers:
469 * rbuff Receive buffer.
470 * xbuff Transmit buffer.
475 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
476 if (sl->rbuff == NULL)
478 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
479 if (sl->xbuff == NULL)
485 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
487 netif_start_queue(dev);
492 err = lapb_register(dev, &x25_asy_callbacks);
505 /* Close the low-level part of the X.25 channel. Easy! */
506 static int x25_asy_close(struct net_device *dev)
508 struct x25_asy *sl = netdev_priv(dev);
510 spin_lock(&sl->lock);
512 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
514 netif_stop_queue(dev);
517 spin_unlock(&sl->lock);
522 * Handle the 'receiver data ready' interrupt.
523 * This function is called by the 'tty_io' module in the kernel when
524 * a block of X.25 data has been received, which can now be decapsulated
525 * and sent on to some IP layer for further processing.
528 static void x25_asy_receive_buf(struct tty_struct *tty,
529 const unsigned char *cp, char *fp, int count)
531 struct x25_asy *sl = tty->disc_data;
533 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
537 /* Read the characters out of the buffer */
540 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
541 sl->dev->stats.rx_errors++;
545 x25_asy_unesc(sl, *cp++);
550 * Open the high-level part of the X.25 channel.
551 * This function is called by the TTY module when the
552 * X.25 line discipline is called for. Because we are
553 * sure the tty line exists, we only have to link it to
554 * a free X.25 channel...
557 static int x25_asy_open_tty(struct tty_struct *tty)
562 if (tty->ops->write == NULL)
565 /* OK. Find a free X.25 channel to use. */
566 sl = x25_asy_alloc();
572 tty->receive_room = 65536;
573 tty_driver_flush_buffer(tty);
574 tty_ldisc_flush(tty);
576 /* Restore default settings */
577 sl->dev->type = ARPHRD_X25;
579 /* Perform the low-level X.25 async init */
580 err = x25_asy_open(sl->dev);
583 /* Done. We have linked the TTY line to a channel. */
589 * Close down an X.25 channel.
590 * This means flushing out any pending queues, and then restoring the
591 * TTY line discipline to what it was before it got hooked to X.25
592 * (which usually is TTY again).
594 static void x25_asy_close_tty(struct tty_struct *tty)
596 struct x25_asy *sl = tty->disc_data;
599 /* First make sure we're connected. */
600 if (!sl || sl->magic != X25_ASY_MAGIC)
604 if (sl->dev->flags & IFF_UP)
608 err = lapb_unregister(sl->dev);
610 pr_err("x25_asy_close: lapb_unregister error: %d\n",
613 tty->disc_data = NULL;
618 /************************************************************************
619 * STANDARD X.25 ENCAPSULATION *
620 ************************************************************************/
622 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
624 unsigned char *ptr = d;
628 * Send an initial END character to flush out any
629 * data that may have accumulated in the receiver
633 *ptr++ = X25_END; /* Send 10111110 bit seq */
636 * For each byte in the packet, send the appropriate
637 * character sequence, according to the X.25 protocol.
644 *ptr++ = X25_ESCAPE(X25_END);
648 *ptr++ = X25_ESCAPE(X25_ESC);
659 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
664 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
667 clear_bit(SLF_ESCAPE, &sl->flags);
671 set_bit(SLF_ESCAPE, &sl->flags);
673 case X25_ESCAPE(X25_ESC):
674 case X25_ESCAPE(X25_END):
675 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
679 if (!test_bit(SLF_ERROR, &sl->flags)) {
680 if (sl->rcount < sl->buffsize) {
681 sl->rbuff[sl->rcount++] = s;
684 sl->dev->stats.rx_over_errors++;
685 set_bit(SLF_ERROR, &sl->flags);
690 /* Perform I/O control on an active X.25 channel. */
691 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
692 unsigned int cmd, unsigned long arg)
694 struct x25_asy *sl = tty->disc_data;
696 /* First make sure we're connected. */
697 if (!sl || sl->magic != X25_ASY_MAGIC)
702 if (copy_to_user((void __user *)arg, sl->dev->name,
703 strlen(sl->dev->name) + 1))
709 return tty_mode_ioctl(tty, file, cmd, arg);
714 static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
715 unsigned int cmd, unsigned long arg)
720 return x25_asy_ioctl(tty, file, cmd,
721 (unsigned long)compat_ptr(arg));
728 static int x25_asy_open_dev(struct net_device *dev)
730 struct x25_asy *sl = netdev_priv(dev);
736 static const struct net_device_ops x25_asy_netdev_ops = {
737 .ndo_open = x25_asy_open_dev,
738 .ndo_stop = x25_asy_close,
739 .ndo_start_xmit = x25_asy_xmit,
740 .ndo_tx_timeout = x25_asy_timeout,
741 .ndo_change_mtu = x25_asy_change_mtu,
744 /* Initialise the X.25 driver. Called by the device init code */
745 static void x25_asy_setup(struct net_device *dev)
747 struct x25_asy *sl = netdev_priv(dev);
749 sl->magic = X25_ASY_MAGIC;
751 spin_lock_init(&sl->lock);
752 set_bit(SLF_INUSE, &sl->flags);
755 * Finish setting up the DEVICE info.
759 dev->netdev_ops = &x25_asy_netdev_ops;
760 dev->watchdog_timeo = HZ*20;
761 dev->hard_header_len = 0;
763 dev->type = ARPHRD_X25;
764 dev->tx_queue_len = 10;
766 /* New-style flags. */
767 dev->flags = IFF_NOARP;
770 static struct tty_ldisc_ops x25_ldisc = {
771 .owner = THIS_MODULE,
772 .magic = TTY_LDISC_MAGIC,
774 .open = x25_asy_open_tty,
775 .close = x25_asy_close_tty,
776 .ioctl = x25_asy_ioctl,
778 .compat_ioctl = x25_asy_compat_ioctl,
780 .receive_buf = x25_asy_receive_buf,
781 .write_wakeup = x25_asy_write_wakeup,
784 static int __init init_x25_asy(void)
786 if (x25_asy_maxdev < 4)
787 x25_asy_maxdev = 4; /* Sanity */
789 pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n",
792 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
797 return tty_register_ldisc(N_X25, &x25_ldisc);
801 static void __exit exit_x25_asy(void)
803 struct net_device *dev;
806 for (i = 0; i < x25_asy_maxdev; i++) {
807 dev = x25_asy_devs[i];
809 struct x25_asy *sl = netdev_priv(dev);
811 spin_lock_bh(&sl->lock);
815 spin_unlock_bh(&sl->lock);
817 * VSV = if dev->start==0, then device
818 * unregistered while close proc.
820 unregister_netdev(dev);
826 tty_unregister_ldisc(N_X25);
829 module_init(init_x25_asy);
830 module_exit(exit_x25_asy);