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 one completely decapsulated IP datagram to the IP layer. */
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+1);
203 netdev_warn(sl->dev, "memory squeeze, dropping packet\n");
204 dev->stats.rx_dropped++;
207 skb_push(skb, 1); /* LAPB internal control */
208 memcpy(skb_put(skb, count), sl->rbuff, count);
209 skb->protocol = x25_type_trans(skb, sl->dev);
210 err = lapb_data_received(skb->dev, skb);
211 if (err != LAPB_OK) {
213 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
216 dev->stats.rx_packets++;
220 /* Encapsulate one IP datagram and stuff into a TTY queue. */
221 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
224 int actual, count, mtu = sl->dev->mtu;
227 /* Sigh, shouldn't occur BUT ... */
229 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
231 sl->dev->stats.tx_dropped++;
237 count = x25_asy_esc(p, sl->xbuff, len);
239 /* Order of next two lines is *very* important.
240 * When we are sending a little amount of data,
241 * the transfer may be completed inside driver.write()
242 * routine, because it's running with interrupts enabled.
243 * In this case we *never* got WRITE_WAKEUP event,
244 * if we did not request it before write operation.
245 * 14 Oct 1994 Dmitry Gorodchanin.
247 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
248 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
249 sl->xleft = count - actual;
250 sl->xhead = sl->xbuff + actual;
252 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
256 * Called by the driver when there's room for more data. If we have
257 * more packets to send, we send them here.
259 static void x25_asy_write_wakeup(struct tty_struct *tty)
262 struct x25_asy *sl = tty->disc_data;
264 /* First make sure we're connected. */
265 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
268 if (sl->xleft <= 0) {
269 /* Now serial buffer is almost free & we can start
270 * transmission of another packet */
271 sl->dev->stats.tx_packets++;
272 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
277 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
282 static void x25_asy_timeout(struct net_device *dev)
284 struct x25_asy *sl = netdev_priv(dev);
286 spin_lock(&sl->lock);
287 if (netif_queue_stopped(dev)) {
288 /* May be we must check transmitter timeout here ?
289 * 14 Oct 1994 Dmitry Gorodchanin.
291 netdev_warn(dev, "transmit timed out, %s?\n",
292 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
293 "bad line quality" : "driver error");
295 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
298 spin_unlock(&sl->lock);
301 /* Encapsulate an IP datagram and kick it into a TTY queue. */
303 static netdev_tx_t x25_asy_xmit(struct sk_buff *skb,
304 struct net_device *dev)
306 struct x25_asy *sl = netdev_priv(dev);
309 if (!netif_running(sl->dev)) {
310 netdev_err(dev, "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 netdev_err(dev, "lapb_connect_request error: %d\n",
325 case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */
326 err = lapb_disconnect_request(dev);
328 netdev_err(dev, "lapb_disconnect_request error: %d\n",
334 skb_pull(skb, 1); /* Remove control byte */
336 * If we are busy already- too bad. We ought to be able
337 * to queue things at this point, to allow for a little
338 * frame buffer. Oh well...
339 * -----------------------------------------------------
340 * I hate queues in X.25 driver. May be it's efficient,
341 * but for me latency is more important. ;)
343 * 14 Oct 1994 Dmitry Gorodchanin.
346 err = lapb_data_request(dev, skb);
347 if (err != LAPB_OK) {
348 netdev_err(dev, "lapb_data_request error: %d\n", err);
357 * LAPB interface boilerplate
361 * Called when I frame data arrives. We did the work above - throw it
365 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
367 return netif_rx(skb);
371 * Data has emerged from the LAPB protocol machine. We don't handle
372 * busy cases too well. Its tricky to see how to do this nicely -
373 * perhaps lapb should allow us to bounce this ?
376 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
378 struct x25_asy *sl = netdev_priv(dev);
380 spin_lock(&sl->lock);
381 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
382 spin_unlock(&sl->lock);
383 netdev_err(dev, "tbusy drop\n");
387 /* We were not busy, so we are now... :-) */
390 dev->stats.tx_bytes += skb->len;
391 x25_asy_encaps(sl, skb->data, skb->len);
394 spin_unlock(&sl->lock);
398 * LAPB connection establish/down information.
401 static void x25_asy_connected(struct net_device *dev, int reason)
403 struct x25_asy *sl = netdev_priv(dev);
407 skb = dev_alloc_skb(1);
409 netdev_err(dev, "out of memory\n");
413 ptr = skb_put(skb, 1);
414 *ptr = X25_IFACE_CONNECT;
416 skb->protocol = x25_type_trans(skb, sl->dev);
420 static void x25_asy_disconnected(struct net_device *dev, int reason)
422 struct x25_asy *sl = netdev_priv(dev);
426 skb = dev_alloc_skb(1);
428 netdev_err(dev, "out of memory\n");
432 ptr = skb_put(skb, 1);
433 *ptr = X25_IFACE_DISCONNECT;
435 skb->protocol = x25_type_trans(skb, sl->dev);
439 static const struct lapb_register_struct x25_asy_callbacks = {
440 .connect_confirmation = x25_asy_connected,
441 .connect_indication = x25_asy_connected,
442 .disconnect_confirmation = x25_asy_disconnected,
443 .disconnect_indication = x25_asy_disconnected,
444 .data_indication = x25_asy_data_indication,
445 .data_transmit = x25_asy_data_transmit,
449 /* Open the low-level part of the X.25 channel. Easy! */
450 static int x25_asy_open(struct net_device *dev)
452 struct x25_asy *sl = netdev_priv(dev);
460 * Allocate the X.25 frame buffers:
462 * rbuff Receive buffer.
463 * xbuff Transmit buffer.
468 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
469 if (sl->rbuff == NULL)
471 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
472 if (sl->xbuff == NULL)
478 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
480 netif_start_queue(dev);
485 err = lapb_register(dev, &x25_asy_callbacks);
498 /* Close the low-level part of the X.25 channel. Easy! */
499 static int x25_asy_close(struct net_device *dev)
501 struct x25_asy *sl = netdev_priv(dev);
503 spin_lock(&sl->lock);
505 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
507 netif_stop_queue(dev);
510 spin_unlock(&sl->lock);
515 * Handle the 'receiver data ready' interrupt.
516 * This function is called by the 'tty_io' module in the kernel when
517 * a block of X.25 data has been received, which can now be decapsulated
518 * and sent on to some IP layer for further processing.
521 static void x25_asy_receive_buf(struct tty_struct *tty,
522 const unsigned char *cp, char *fp, int count)
524 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++);
543 * Open the high-level part of the X.25 channel.
544 * This function is called by the TTY module when the
545 * X.25 line discipline is called for. Because we are
546 * sure the tty line exists, we only have to link it to
547 * a free X.25 channel...
550 static int x25_asy_open_tty(struct tty_struct *tty)
552 struct x25_asy *sl = tty->disc_data;
555 if (tty->ops->write == NULL)
558 /* First make sure we're not already connected. */
559 if (sl && sl->magic == X25_ASY_MAGIC)
562 /* OK. Find a free X.25 channel to use. */
563 sl = x25_asy_alloc();
569 tty->receive_room = 65536;
570 tty_driver_flush_buffer(tty);
571 tty_ldisc_flush(tty);
573 /* Restore default settings */
574 sl->dev->type = ARPHRD_X25;
576 /* Perform the low-level X.25 async init */
577 err = x25_asy_open(sl->dev);
580 /* Done. We have linked the TTY line to a channel. */
586 * Close down an X.25 channel.
587 * This means flushing out any pending queues, and then restoring the
588 * TTY line discipline to what it was before it got hooked to X.25
589 * (which usually is TTY again).
591 static void x25_asy_close_tty(struct tty_struct *tty)
593 struct x25_asy *sl = tty->disc_data;
596 /* First make sure we're connected. */
597 if (!sl || sl->magic != X25_ASY_MAGIC)
601 if (sl->dev->flags & IFF_UP)
605 err = lapb_unregister(sl->dev);
607 pr_err("x25_asy_close: lapb_unregister error: %d\n",
610 tty->disc_data = NULL;
615 /************************************************************************
616 * STANDARD X.25 ENCAPSULATION *
617 ************************************************************************/
619 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
621 unsigned char *ptr = d;
625 * Send an initial END character to flush out any
626 * data that may have accumulated in the receiver
630 *ptr++ = X25_END; /* Send 10111110 bit seq */
633 * For each byte in the packet, send the appropriate
634 * character sequence, according to the X.25 protocol.
641 *ptr++ = X25_ESCAPE(X25_END);
645 *ptr++ = X25_ESCAPE(X25_ESC);
656 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
661 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
664 clear_bit(SLF_ESCAPE, &sl->flags);
668 set_bit(SLF_ESCAPE, &sl->flags);
670 case X25_ESCAPE(X25_ESC):
671 case X25_ESCAPE(X25_END):
672 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
676 if (!test_bit(SLF_ERROR, &sl->flags)) {
677 if (sl->rcount < sl->buffsize) {
678 sl->rbuff[sl->rcount++] = s;
681 sl->dev->stats.rx_over_errors++;
682 set_bit(SLF_ERROR, &sl->flags);
687 /* Perform I/O control on an active X.25 channel. */
688 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
689 unsigned int cmd, unsigned long arg)
691 struct x25_asy *sl = tty->disc_data;
693 /* First make sure we're connected. */
694 if (!sl || sl->magic != X25_ASY_MAGIC)
699 if (copy_to_user((void __user *)arg, sl->dev->name,
700 strlen(sl->dev->name) + 1))
706 return tty_mode_ioctl(tty, file, cmd, arg);
711 static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file,
712 unsigned int cmd, unsigned long arg)
717 return x25_asy_ioctl(tty, file, cmd,
718 (unsigned long)compat_ptr(arg));
725 static int x25_asy_open_dev(struct net_device *dev)
727 struct x25_asy *sl = netdev_priv(dev);
733 static const struct net_device_ops x25_asy_netdev_ops = {
734 .ndo_open = x25_asy_open_dev,
735 .ndo_stop = x25_asy_close,
736 .ndo_start_xmit = x25_asy_xmit,
737 .ndo_tx_timeout = x25_asy_timeout,
738 .ndo_change_mtu = x25_asy_change_mtu,
741 /* Initialise the X.25 driver. Called by the device init code */
742 static void x25_asy_setup(struct net_device *dev)
744 struct x25_asy *sl = netdev_priv(dev);
746 sl->magic = X25_ASY_MAGIC;
748 spin_lock_init(&sl->lock);
749 set_bit(SLF_INUSE, &sl->flags);
752 * Finish setting up the DEVICE info.
756 dev->netdev_ops = &x25_asy_netdev_ops;
757 dev->watchdog_timeo = HZ*20;
758 dev->hard_header_len = 0;
760 dev->type = ARPHRD_X25;
761 dev->tx_queue_len = 10;
763 /* New-style flags. */
764 dev->flags = IFF_NOARP;
767 static struct tty_ldisc_ops x25_ldisc = {
768 .owner = THIS_MODULE,
769 .magic = TTY_LDISC_MAGIC,
771 .open = x25_asy_open_tty,
772 .close = x25_asy_close_tty,
773 .ioctl = x25_asy_ioctl,
775 .compat_ioctl = x25_asy_compat_ioctl,
777 .receive_buf = x25_asy_receive_buf,
778 .write_wakeup = x25_asy_write_wakeup,
781 static int __init init_x25_asy(void)
783 if (x25_asy_maxdev < 4)
784 x25_asy_maxdev = 4; /* Sanity */
786 pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n",
789 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
794 return tty_register_ldisc(N_X25, &x25_ldisc);
798 static void __exit exit_x25_asy(void)
800 struct net_device *dev;
803 for (i = 0; i < x25_asy_maxdev; i++) {
804 dev = x25_asy_devs[i];
806 struct x25_asy *sl = netdev_priv(dev);
808 spin_lock_bh(&sl->lock);
812 spin_unlock_bh(&sl->lock);
814 * VSV = if dev->start==0, then device
815 * unregistered while close proc.
817 unregister_netdev(dev);
823 tty_unregister_ldisc(N_X25);
826 module_init(init_x25_asy);
827 module_exit(exit_x25_asy);