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 <asm/system.h>
22 #include <linux/uaccess.h>
23 #include <linux/bitops.h>
24 #include <linux/string.h>
26 #include <linux/interrupt.h>
28 #include <linux/tty.h>
29 #include <linux/errno.h>
30 #include <linux/netdevice.h>
31 #include <linux/etherdevice.h>
32 #include <linux/skbuff.h>
33 #include <linux/if_arp.h>
34 #include <linux/lapb.h>
35 #include <linux/init.h>
36 #include <linux/rtnetlink.h>
37 #include <linux/compat.h>
38 #include <linux/slab.h>
39 #include <net/x25device.h>
42 static struct net_device **x25_asy_devs;
43 static int x25_asy_maxdev = SL_NRUNIT;
45 module_param(x25_asy_maxdev, int, 0);
46 MODULE_LICENSE("GPL");
48 static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
49 static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
50 static void x25_asy_setup(struct net_device *dev);
52 /* Find a free X.25 channel, and link in this `tty' line. */
53 static struct x25_asy *x25_asy_alloc(void)
55 struct net_device *dev = NULL;
59 if (x25_asy_devs == NULL)
60 return NULL; /* Master array missing ! */
62 for (i = 0; i < x25_asy_maxdev; i++) {
63 dev = x25_asy_devs[i];
69 sl = netdev_priv(dev);
71 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
76 /* Sorry, too many, all slots in use */
77 if (i >= x25_asy_maxdev)
80 /* If no channels are available, allocate one */
83 sprintf(name, "x25asy%d", i);
85 dev = alloc_netdev(sizeof(struct x25_asy),
90 /* Initialize channel control data */
91 sl = netdev_priv(dev);
94 /* register device so that it can be ifconfig'ed */
95 if (register_netdev(dev) == 0) {
96 /* (Re-)Set the INUSE bit. Very Important! */
97 set_bit(SLF_INUSE, &sl->flags);
98 x25_asy_devs[i] = dev;
101 pr_warn("%s(): register_netdev() failure\n", __func__);
109 /* Free an X.25 channel. */
110 static void x25_asy_free(struct x25_asy *sl)
112 /* Free all X.25 frame buffers. */
118 if (!test_and_clear_bit(SLF_INUSE, &sl->flags))
119 netdev_err(sl->dev, "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 netdev_warn(dev, "unable to grow X.25 buffers, MTU change cancelled\n");
138 spin_lock_bh(&sl->lock);
139 xbuff = xchg(&sl->xbuff, xbuff);
141 if (sl->xleft <= len) {
142 memcpy(sl->xbuff, sl->xhead, sl->xleft);
145 dev->stats.tx_dropped++;
148 sl->xhead = sl->xbuff;
150 rbuff = xchg(&sl->rbuff, rbuff);
152 if (sl->rcount <= len) {
153 memcpy(sl->rbuff, rbuff, sl->rcount);
156 dev->stats.rx_over_errors++;
157 set_bit(SLF_ERROR, &sl->flags);
164 spin_unlock_bh(&sl->lock);
172 /* Set the "sending" flag. This must be atomic, hence the ASM. */
174 static inline void x25_asy_lock(struct x25_asy *sl)
176 netif_stop_queue(sl->dev);
180 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
182 static inline void x25_asy_unlock(struct x25_asy *sl)
184 netif_wake_queue(sl->dev);
187 /* Send one completely decapsulated IP datagram to the IP layer. */
189 static void x25_asy_bump(struct x25_asy *sl)
191 struct net_device *dev = sl->dev;
197 dev->stats.rx_bytes += count;
199 skb = dev_alloc_skb(count+1);
201 netdev_warn(sl->dev, "memory squeeze, dropping packet\n");
202 dev->stats.rx_dropped++;
205 skb_push(skb, 1); /* LAPB internal control */
206 memcpy(skb_put(skb, count), sl->rbuff, count);
207 skb->protocol = x25_type_trans(skb, sl->dev);
208 err = lapb_data_received(skb->dev, skb);
209 if (err != LAPB_OK) {
211 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, (unsigned char *) 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 arrives. We did the work above - throw it
363 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
365 return netif_rx(skb);
369 * Data has emerged from the LAPB protocol machine. We don't handle
370 * busy cases too well. Its tricky to see how to do this nicely -
371 * perhaps lapb should allow us to bounce this ?
374 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
376 struct x25_asy *sl = netdev_priv(dev);
378 spin_lock(&sl->lock);
379 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
380 spin_unlock(&sl->lock);
381 netdev_err(dev, "tbusy drop\n");
385 /* We were not busy, so we are now... :-) */
388 dev->stats.tx_bytes += skb->len;
389 x25_asy_encaps(sl, skb->data, skb->len);
392 spin_unlock(&sl->lock);
396 * LAPB connection establish/down information.
399 static void x25_asy_connected(struct net_device *dev, int reason)
401 struct x25_asy *sl = netdev_priv(dev);
405 skb = dev_alloc_skb(1);
407 netdev_err(dev, "out of memory\n");
411 ptr = skb_put(skb, 1);
412 *ptr = X25_IFACE_CONNECT;
414 skb->protocol = x25_type_trans(skb, sl->dev);
418 static void x25_asy_disconnected(struct net_device *dev, int reason)
420 struct x25_asy *sl = netdev_priv(dev);
424 skb = dev_alloc_skb(1);
426 netdev_err(dev, "out of memory\n");
430 ptr = skb_put(skb, 1);
431 *ptr = X25_IFACE_DISCONNECT;
433 skb->protocol = x25_type_trans(skb, sl->dev);
437 static const struct lapb_register_struct x25_asy_callbacks = {
438 .connect_confirmation = x25_asy_connected,
439 .connect_indication = x25_asy_connected,
440 .disconnect_confirmation = x25_asy_disconnected,
441 .disconnect_indication = x25_asy_disconnected,
442 .data_indication = x25_asy_data_indication,
443 .data_transmit = x25_asy_data_transmit,
447 /* Open the low-level part of the X.25 channel. Easy! */
448 static int x25_asy_open(struct net_device *dev)
450 struct x25_asy *sl = netdev_priv(dev);
458 * Allocate the X.25 frame buffers:
460 * rbuff Receive buffer.
461 * xbuff Transmit buffer.
466 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
467 if (sl->rbuff == NULL)
469 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
470 if (sl->xbuff == NULL)
476 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
478 netif_start_queue(dev);
483 err = lapb_register(dev, &x25_asy_callbacks);
496 /* Close the low-level part of the X.25 channel. Easy! */
497 static int x25_asy_close(struct net_device *dev)
499 struct x25_asy *sl = netdev_priv(dev);
501 spin_lock(&sl->lock);
503 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
505 netif_stop_queue(dev);
508 spin_unlock(&sl->lock);
513 * Handle the 'receiver data ready' interrupt.
514 * This function is called by the 'tty_io' module in the kernel when
515 * a block of X.25 data has been received, which can now be decapsulated
516 * and sent on to some IP layer for further processing.
519 static void x25_asy_receive_buf(struct tty_struct *tty,
520 const unsigned char *cp, char *fp, int count)
522 struct x25_asy *sl = tty->disc_data;
524 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
528 /* Read the characters out of the buffer */
531 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
532 sl->dev->stats.rx_errors++;
536 x25_asy_unesc(sl, *cp++);
541 * Open the high-level part of the X.25 channel.
542 * This function is called by the TTY module when the
543 * X.25 line discipline is called for. Because we are
544 * sure the tty line exists, we only have to link it to
545 * a free X.25 channel...
548 static int x25_asy_open_tty(struct tty_struct *tty)
550 struct x25_asy *sl = tty->disc_data;
553 if (tty->ops->write == NULL)
556 /* First make sure we're not already connected. */
557 if (sl && sl->magic == X25_ASY_MAGIC)
560 /* OK. Find a free X.25 channel to use. */
561 sl = x25_asy_alloc();
567 tty->receive_room = 65536;
568 tty_driver_flush_buffer(tty);
569 tty_ldisc_flush(tty);
571 /* Restore default settings */
572 sl->dev->type = ARPHRD_X25;
574 /* Perform the low-level X.25 async init */
575 err = x25_asy_open(sl->dev);
578 /* Done. We have linked the TTY line to a channel. */
584 * Close down an X.25 channel.
585 * This means flushing out any pending queues, and then restoring the
586 * TTY line discipline to what it was before it got hooked to X.25
587 * (which usually is TTY again).
589 static void x25_asy_close_tty(struct tty_struct *tty)
591 struct x25_asy *sl = tty->disc_data;
594 /* First make sure we're connected. */
595 if (!sl || sl->magic != X25_ASY_MAGIC)
599 if (sl->dev->flags & IFF_UP)
603 err = lapb_unregister(sl->dev);
605 pr_err("x25_asy_close: lapb_unregister error: %d\n",
608 tty->disc_data = NULL;
613 /************************************************************************
614 * STANDARD X.25 ENCAPSULATION *
615 ************************************************************************/
617 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
619 unsigned char *ptr = d;
623 * Send an initial END character to flush out any
624 * data that may have accumulated in the receiver
628 *ptr++ = X25_END; /* Send 10111110 bit seq */
631 * For each byte in the packet, send the appropriate
632 * character sequence, according to the X.25 protocol.
639 *ptr++ = X25_ESCAPE(X25_END);
643 *ptr++ = X25_ESCAPE(X25_ESC);
654 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
659 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
662 clear_bit(SLF_ESCAPE, &sl->flags);
666 set_bit(SLF_ESCAPE, &sl->flags);
668 case X25_ESCAPE(X25_ESC):
669 case X25_ESCAPE(X25_END):
670 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
674 if (!test_bit(SLF_ERROR, &sl->flags)) {
675 if (sl->rcount < sl->buffsize) {
676 sl->rbuff[sl->rcount++] = s;
679 sl->dev->stats.rx_over_errors++;
680 set_bit(SLF_ERROR, &sl->flags);
685 /* Perform I/O control on an active X.25 channel. */
686 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
687 unsigned int cmd, unsigned long arg)
689 struct x25_asy *sl = tty->disc_data;
691 /* First make sure we're connected. */
692 if (!sl || sl->magic != X25_ASY_MAGIC)
697 if (copy_to_user((void __user *)arg, sl->dev->name,
698 strlen(sl->dev->name) + 1))
704 return tty_mode_ioctl(tty, file, cmd, arg);
709 static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
710 unsigned int cmd, unsigned long arg)
715 return x25_asy_ioctl(tty, file, cmd,
716 (unsigned long)compat_ptr(arg));
723 static int x25_asy_open_dev(struct net_device *dev)
725 struct x25_asy *sl = netdev_priv(dev);
731 static const struct net_device_ops x25_asy_netdev_ops = {
732 .ndo_open = x25_asy_open_dev,
733 .ndo_stop = x25_asy_close,
734 .ndo_start_xmit = x25_asy_xmit,
735 .ndo_tx_timeout = x25_asy_timeout,
736 .ndo_change_mtu = x25_asy_change_mtu,
739 /* Initialise the X.25 driver. Called by the device init code */
740 static void x25_asy_setup(struct net_device *dev)
742 struct x25_asy *sl = netdev_priv(dev);
744 sl->magic = X25_ASY_MAGIC;
746 spin_lock_init(&sl->lock);
747 set_bit(SLF_INUSE, &sl->flags);
750 * Finish setting up the DEVICE info.
754 dev->netdev_ops = &x25_asy_netdev_ops;
755 dev->watchdog_timeo = HZ*20;
756 dev->hard_header_len = 0;
758 dev->type = ARPHRD_X25;
759 dev->tx_queue_len = 10;
761 /* New-style flags. */
762 dev->flags = IFF_NOARP;
765 static struct tty_ldisc_ops x25_ldisc = {
766 .owner = THIS_MODULE,
767 .magic = TTY_LDISC_MAGIC,
769 .open = x25_asy_open_tty,
770 .close = x25_asy_close_tty,
771 .ioctl = x25_asy_ioctl,
773 .compat_ioctl = x25_asy_compat_ioctl,
775 .receive_buf = x25_asy_receive_buf,
776 .write_wakeup = x25_asy_write_wakeup,
779 static int __init init_x25_asy(void)
781 if (x25_asy_maxdev < 4)
782 x25_asy_maxdev = 4; /* Sanity */
784 pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n",
787 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
792 return tty_register_ldisc(N_X25, &x25_ldisc);
796 static void __exit exit_x25_asy(void)
798 struct net_device *dev;
801 for (i = 0; i < x25_asy_maxdev; i++) {
802 dev = x25_asy_devs[i];
804 struct x25_asy *sl = netdev_priv(dev);
806 spin_lock_bh(&sl->lock);
810 spin_unlock_bh(&sl->lock);
812 * VSV = if dev->start==0, then device
813 * unregistered while close proc.
815 unregister_netdev(dev);
821 tty_unregister_ldisc(N_X25);
824 module_init(init_x25_asy);
825 module_exit(exit_x25_asy);