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/lapb.h>
33 #include <linux/init.h>
34 #include <linux/rtnetlink.h>
35 #include <linux/compat.h>
36 #include <linux/slab.h>
37 #include <net/x25device.h>
40 static struct net_device **x25_asy_devs;
41 static int x25_asy_maxdev = SL_NRUNIT;
43 module_param(x25_asy_maxdev, int, 0);
44 MODULE_LICENSE("GPL");
46 static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
47 static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
48 static void x25_asy_setup(struct net_device *dev);
50 /* Find a free X.25 channel, and link in this `tty' line. */
51 static struct x25_asy *x25_asy_alloc(void)
53 struct net_device *dev = NULL;
57 if (x25_asy_devs == NULL)
58 return NULL; /* Master array missing ! */
60 for (i = 0; i < x25_asy_maxdev; i++) {
61 dev = x25_asy_devs[i];
67 sl = netdev_priv(dev);
69 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
74 /* Sorry, too many, all slots in use */
75 if (i >= x25_asy_maxdev)
78 /* If no channels are available, allocate one */
81 sprintf(name, "x25asy%d", i);
83 dev = alloc_netdev(sizeof(struct x25_asy),
88 /* Initialize channel control data */
89 sl = netdev_priv(dev);
92 /* register device so that it can be ifconfig'ed */
93 if (register_netdev(dev) == 0) {
94 /* (Re-)Set the INUSE bit. Very Important! */
95 set_bit(SLF_INUSE, &sl->flags);
96 x25_asy_devs[i] = dev;
99 printk(KERN_WARNING "x25_asy_alloc() - register_netdev() failure.\n");
107 /* Free an X.25 channel. */
108 static void x25_asy_free(struct x25_asy *sl)
110 /* Free all X.25 frame buffers. */
116 if (!test_and_clear_bit(SLF_INUSE, &sl->flags))
117 printk(KERN_ERR "%s: 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) {
131 printk(KERN_WARNING "%s: 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 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n",
203 dev->stats.rx_dropped++;
206 skb_push(skb, 1); /* LAPB internal control */
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);
215 dev->stats.rx_packets++;
219 /* Encapsulate one IP datagram and stuff into a TTY queue. */
220 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
223 int actual, count, mtu = sl->dev->mtu;
226 /* Sigh, shouldn't occur BUT ... */
228 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
230 sl->dev->stats.tx_dropped++;
236 count = x25_asy_esc(p, (unsigned char *) sl->xbuff, len);
238 /* Order of next two lines is *very* important.
239 * When we are sending a little amount of data,
240 * the transfer may be completed inside driver.write()
241 * routine, because it's running with interrupts enabled.
242 * In this case we *never* got WRITE_WAKEUP event,
243 * if we did not request it before write operation.
244 * 14 Oct 1994 Dmitry Gorodchanin.
246 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
247 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
248 sl->xleft = count - actual;
249 sl->xhead = sl->xbuff + actual;
251 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
255 * Called by the driver when there's room for more data. If we have
256 * more packets to send, we send them here.
258 static void x25_asy_write_wakeup(struct tty_struct *tty)
261 struct x25_asy *sl = tty->disc_data;
263 /* First make sure we're connected. */
264 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
267 if (sl->xleft <= 0) {
268 /* Now serial buffer is almost free & we can start
269 * transmission of another packet */
270 sl->dev->stats.tx_packets++;
271 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
276 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
281 static void x25_asy_timeout(struct net_device *dev)
283 struct x25_asy *sl = netdev_priv(dev);
285 spin_lock(&sl->lock);
286 if (netif_queue_stopped(dev)) {
287 /* May be we must check transmitter timeout here ?
288 * 14 Oct 1994 Dmitry Gorodchanin.
290 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
291 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
292 "bad line quality" : "driver error");
294 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
297 spin_unlock(&sl->lock);
300 /* Encapsulate an IP datagram and kick it into a TTY queue. */
302 static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
303 struct net_device *dev)
305 struct x25_asy *sl = netdev_priv(dev);
308 if (!netif_running(sl->dev)) {
309 printk(KERN_ERR "%s: xmit call when iface is down\n",
315 switch (skb->data[0]) {
318 case X25_IFACE_CONNECT: /* Connection request .. do nothing */
319 err = lapb_connect_request(dev);
321 printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
324 case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
325 err = lapb_disconnect_request(dev);
327 printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
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 printk(KERN_ERR "x25_asy: 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 printk(KERN_ERR "x25_asy: 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 printk(KERN_ERR "x25_asy: 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 printk(KERN_ERR "x25_asy: 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 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,
448 /* Open the low-level part of the X.25 channel. Easy! */
449 static int x25_asy_open(struct net_device *dev)
451 struct x25_asy *sl = netdev_priv(dev);
459 * Allocate the X.25 frame buffers:
461 * rbuff Receive buffer.
462 * xbuff Transmit buffer.
467 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
468 if (sl->rbuff == NULL)
470 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
471 if (sl->xbuff == NULL)
477 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
479 netif_start_queue(dev);
484 err = lapb_register(dev, &x25_asy_callbacks);
497 /* Close the low-level part of the X.25 channel. Easy! */
498 static int x25_asy_close(struct net_device *dev)
500 struct x25_asy *sl = netdev_priv(dev);
502 spin_lock(&sl->lock);
504 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
506 netif_stop_queue(dev);
509 spin_unlock(&sl->lock);
514 * Handle the 'receiver data ready' interrupt.
515 * This function is called by the 'tty_io' module in the kernel when
516 * a block of X.25 data has been received, which can now be decapsulated
517 * and sent on to some IP layer for further processing.
520 static unsigned int x25_asy_receive_buf(struct tty_struct *tty,
521 const unsigned char *cp, char *fp, int count)
523 struct x25_asy *sl = tty->disc_data;
526 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
530 /* Read the characters out of the buffer */
533 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
534 sl->dev->stats.rx_errors++;
538 x25_asy_unesc(sl, *cp++);
545 * Open the high-level part of the X.25 channel.
546 * This function is called by the TTY module when the
547 * X.25 line discipline is called for. Because we are
548 * sure the tty line exists, we only have to link it to
549 * a free X.25 channel...
552 static int x25_asy_open_tty(struct tty_struct *tty)
554 struct x25_asy *sl = tty->disc_data;
557 if (tty->ops->write == NULL)
560 /* First make sure we're not already connected. */
561 if (sl && sl->magic == X25_ASY_MAGIC)
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);
582 /* Done. We have linked the TTY line to a channel. */
588 * Close down an X.25 channel.
589 * This means flushing out any pending queues, and then restoring the
590 * TTY line discipline to what it was before it got hooked to X.25
591 * (which usually is TTY again).
593 static void x25_asy_close_tty(struct tty_struct *tty)
595 struct x25_asy *sl = tty->disc_data;
598 /* First make sure we're connected. */
599 if (!sl || sl->magic != X25_ASY_MAGIC)
603 if (sl->dev->flags & IFF_UP)
607 err = lapb_unregister(sl->dev);
609 printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",
612 tty->disc_data = NULL;
617 /************************************************************************
618 * STANDARD X.25 ENCAPSULATION *
619 ************************************************************************/
621 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
623 unsigned char *ptr = d;
627 * Send an initial END character to flush out any
628 * data that may have accumulated in the receiver
632 *ptr++ = X25_END; /* Send 10111110 bit seq */
635 * For each byte in the packet, send the appropriate
636 * character sequence, according to the X.25 protocol.
643 *ptr++ = X25_ESCAPE(X25_END);
647 *ptr++ = X25_ESCAPE(X25_ESC);
658 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
663 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
666 clear_bit(SLF_ESCAPE, &sl->flags);
670 set_bit(SLF_ESCAPE, &sl->flags);
672 case X25_ESCAPE(X25_ESC):
673 case X25_ESCAPE(X25_END):
674 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
678 if (!test_bit(SLF_ERROR, &sl->flags)) {
679 if (sl->rcount < sl->buffsize) {
680 sl->rbuff[sl->rcount++] = s;
683 sl->dev->stats.rx_over_errors++;
684 set_bit(SLF_ERROR, &sl->flags);
689 /* Perform I/O control on an active X.25 channel. */
690 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
691 unsigned int cmd, unsigned long arg)
693 struct x25_asy *sl = tty->disc_data;
695 /* First make sure we're connected. */
696 if (!sl || sl->magic != X25_ASY_MAGIC)
701 if (copy_to_user((void __user *)arg, sl->dev->name,
702 strlen(sl->dev->name) + 1))
708 return tty_mode_ioctl(tty, file, cmd, arg);
713 static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
714 unsigned int cmd, unsigned long arg)
719 return x25_asy_ioctl(tty, file, cmd,
720 (unsigned long)compat_ptr(arg));
727 static int x25_asy_open_dev(struct net_device *dev)
729 struct x25_asy *sl = netdev_priv(dev);
735 static const struct net_device_ops x25_asy_netdev_ops = {
736 .ndo_open = x25_asy_open_dev,
737 .ndo_stop = x25_asy_close,
738 .ndo_start_xmit = x25_asy_xmit,
739 .ndo_tx_timeout = x25_asy_timeout,
740 .ndo_change_mtu = x25_asy_change_mtu,
743 /* Initialise the X.25 driver. Called by the device init code */
744 static void x25_asy_setup(struct net_device *dev)
746 struct x25_asy *sl = netdev_priv(dev);
748 sl->magic = X25_ASY_MAGIC;
750 spin_lock_init(&sl->lock);
751 set_bit(SLF_INUSE, &sl->flags);
754 * Finish setting up the DEVICE info.
758 dev->netdev_ops = &x25_asy_netdev_ops;
759 dev->watchdog_timeo = HZ*20;
760 dev->hard_header_len = 0;
762 dev->type = ARPHRD_X25;
763 dev->tx_queue_len = 10;
765 /* New-style flags. */
766 dev->flags = IFF_NOARP;
769 static struct tty_ldisc_ops x25_ldisc = {
770 .owner = THIS_MODULE,
771 .magic = TTY_LDISC_MAGIC,
773 .open = x25_asy_open_tty,
774 .close = x25_asy_close_tty,
775 .ioctl = x25_asy_ioctl,
777 .compat_ioctl = x25_asy_compat_ioctl,
779 .receive_buf = x25_asy_receive_buf,
780 .write_wakeup = x25_asy_write_wakeup,
783 static int __init init_x25_asy(void)
785 if (x25_asy_maxdev < 4)
786 x25_asy_maxdev = 4; /* Sanity */
788 printk(KERN_INFO "X.25 async: version 0.00 ALPHA "
789 "(dynamic channels, max=%d).\n", x25_asy_maxdev);
791 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
794 printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] "
795 "array! Uaargh! (-> No X.25 available)\n");
799 return tty_register_ldisc(N_X25, &x25_ldisc);
803 static void __exit exit_x25_asy(void)
805 struct net_device *dev;
808 for (i = 0; i < x25_asy_maxdev; i++) {
809 dev = x25_asy_devs[i];
811 struct x25_asy *sl = netdev_priv(dev);
813 spin_lock_bh(&sl->lock);
817 spin_unlock_bh(&sl->lock);
819 * VSV = if dev->start==0, then device
820 * unregistered while close proc.
822 unregister_netdev(dev);
828 tty_unregister_ldisc(N_X25);
831 module_init(init_x25_asy);
832 module_exit(exit_x25_asy);