2 * slip.c This module implements the SLIP protocol for kernel-based
3 * devices like TTY. It interfaces between a raw TTY, and the
4 * kernel's INET protocol layers.
6 * Version: @(#)slip.c 0.8.3 12/24/94
8 * Authors: Laurence Culhane, <loz@holmes.demon.co.uk>
9 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
12 * Alan Cox : Sanity checks and avoid tx overruns.
13 * Has a new sl->mtu field.
14 * Alan Cox : Found cause of overrun. ifconfig sl0 mtu upwards.
15 * Driver now spots this and grows/shrinks its buffers(hack!).
16 * Memory leak if you run out of memory setting up a slip driver fixed.
17 * Matt Dillon : Printable slip (borrowed from NET2E)
18 * Pauline Middelink : Slip driver fixes.
19 * Alan Cox : Honours the old SL_COMPRESSED flag
20 * Alan Cox : KISS AX.25 and AXUI IP support
21 * Michael Riepe : Automatic CSLIP recognition added
22 * Charles Hedrick : CSLIP header length problem fix.
23 * Alan Cox : Corrected non-IP cases of the above.
24 * Alan Cox : Now uses hardware type as per FvK.
25 * Alan Cox : Default to 192.168.0.0 (RFC 1597)
26 * A.N.Kuznetsov : dev_tint() recursion fix.
27 * Dmitry Gorodchanin : SLIP memory leaks
28 * Dmitry Gorodchanin : Code cleanup. Reduce tty driver
29 * buffering from 4096 to 256 bytes.
30 * Improving SLIP response time.
31 * CONFIG_SLIP_MODE_SLIP6.
32 * ifconfig sl? up & down now works correctly.
34 * Alan Cox : Oops - fix AX.25 buffer lengths
35 * Dmitry Gorodchanin : Even more cleanups. Preserve CSLIP
36 * statistics. Include CSLIP code only
37 * if it really needed.
38 * Alan Cox : Free slhc buffers in the right place.
39 * Alan Cox : Allow for digipeated IP over AX.25
40 * Matti Aarnio : Dynamic SLIP devices, with ideas taken
41 * from Jim Freeman's <jfree@caldera.com>
42 * dynamic PPP devices. We do NOT kfree()
43 * device entries, just reg./unreg. them
44 * as they are needed. We kfree() them
46 * With MODULE-loading ``insmod'', user can
47 * issue parameter: slip_maxdev=1024
48 * (Or how much he/she wants.. Default is 256)
49 * * Stanislav Voronyi : Slip line checking, with ideas taken
50 * from multislip BSDI driver which was written
51 * by Igor Chechik, RELCOM Corp. Only algorithms
52 * have been ported to Linux SLIP driver.
53 * Vitaly E. Lavrov : Sane behaviour on tty hangup.
54 * Alexey Kuznetsov : Cleanup interfaces to tty&netdevice modules.
57 #define SL_CHECK_TRANSMIT
58 #include <linux/config.h>
59 #include <linux/module.h>
60 #include <linux/moduleparam.h>
62 #include <asm/system.h>
63 #include <asm/uaccess.h>
64 #include <linux/bitops.h>
65 #include <linux/string.h>
67 #include <linux/interrupt.h>
69 #include <linux/tty.h>
70 #include <linux/errno.h>
71 #include <linux/netdevice.h>
72 #include <linux/etherdevice.h>
73 #include <linux/skbuff.h>
74 #include <linux/rtnetlink.h>
75 #include <linux/if_arp.h>
76 #include <linux/if_slip.h>
77 #include <linux/init.h>
81 #include <linux/tcp.h>
82 #include <net/slhc_vj.h>
85 #define SLIP_VERSION "0.8.4-NET3.019-NEWTTY"
87 static struct net_device **slip_devs;
89 static int slip_maxdev = SL_NRUNIT;
90 module_param(slip_maxdev, int, 0);
91 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
93 static int slip_esc(unsigned char *p, unsigned char *d, int len);
94 static void slip_unesc(struct slip *sl, unsigned char c);
95 #ifdef CONFIG_SLIP_MODE_SLIP6
96 static int slip_esc6(unsigned char *p, unsigned char *d, int len);
97 static void slip_unesc6(struct slip *sl, unsigned char c);
99 #ifdef CONFIG_SLIP_SMART
100 static void sl_keepalive(unsigned long sls);
101 static void sl_outfill(unsigned long sls);
102 static int sl_ioctl(struct net_device *dev,struct ifreq *rq,int cmd);
105 /********************************
106 * Buffer administration routines:
111 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because
112 * sl_realloc_bufs provides strong atomicity and reallocation
113 * on actively running device.
114 *********************************/
117 Allocate channel buffers.
121 sl_alloc_bufs(struct slip *sl, int mtu)
127 #ifdef SL_INCLUDE_CSLIP
129 struct slcompress *slcomp = NULL;
133 * Allocate the SLIP frame buffers:
135 * rbuff Receive buffer.
136 * xbuff Transmit buffer.
137 * cbuff Temporary compression buffer.
142 * allow for arrival of larger UDP packets, even if we say not to
143 * also fixes a bug in which SunOS sends 512-byte packets even with
148 rbuff = kmalloc(len + 4, GFP_KERNEL);
151 xbuff = kmalloc(len + 4, GFP_KERNEL);
154 #ifdef SL_INCLUDE_CSLIP
155 cbuff = kmalloc(len + 4, GFP_KERNEL);
158 slcomp = slhc_init(16, 16);
162 spin_lock_bh(&sl->lock);
163 if (sl->tty == NULL) {
164 spin_unlock_bh(&sl->lock);
172 rbuff = xchg(&sl->rbuff, rbuff);
173 xbuff = xchg(&sl->xbuff, xbuff);
174 #ifdef SL_INCLUDE_CSLIP
175 cbuff = xchg(&sl->cbuff, cbuff);
176 slcomp = xchg(&sl->slcomp, slcomp);
177 #ifdef CONFIG_SLIP_MODE_SLIP6
182 spin_unlock_bh(&sl->lock);
187 #ifdef SL_INCLUDE_CSLIP
197 /* Free a SLIP channel buffers. */
199 sl_free_bufs(struct slip *sl)
201 /* Free all SLIP frame buffers. */
202 kfree(xchg(&sl->rbuff, NULL));
203 kfree(xchg(&sl->xbuff, NULL));
204 #ifdef SL_INCLUDE_CSLIP
205 kfree(xchg(&sl->cbuff, NULL));
206 slhc_free(xchg(&sl->slcomp, NULL));
211 Reallocate slip channel buffers.
214 static int sl_realloc_bufs(struct slip *sl, int mtu)
217 struct net_device *dev = sl->dev;
218 unsigned char *xbuff, *rbuff;
219 #ifdef SL_INCLUDE_CSLIP
220 unsigned char *cbuff;
225 * allow for arrival of larger UDP packets, even if we say not to
226 * also fixes a bug in which SunOS sends 512-byte packets even with
232 xbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
233 rbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
234 #ifdef SL_INCLUDE_CSLIP
235 cbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
239 #ifdef SL_INCLUDE_CSLIP
240 if (xbuff == NULL || rbuff == NULL || cbuff == NULL) {
242 if (xbuff == NULL || rbuff == NULL) {
244 if (mtu >= sl->mtu) {
245 printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n",
252 spin_lock_bh(&sl->lock);
258 xbuff = xchg(&sl->xbuff, xbuff);
259 rbuff = xchg(&sl->rbuff, rbuff);
260 #ifdef SL_INCLUDE_CSLIP
261 cbuff = xchg(&sl->cbuff, cbuff);
264 if (sl->xleft <= len) {
265 memcpy(sl->xbuff, sl->xhead, sl->xleft);
271 sl->xhead = sl->xbuff;
274 if (sl->rcount <= len) {
275 memcpy(sl->rbuff, rbuff, sl->rcount);
278 sl->rx_over_errors++;
279 set_bit(SLF_ERROR, &sl->flags);
288 spin_unlock_bh(&sl->lock);
293 #ifdef SL_INCLUDE_CSLIP
300 /* Set the "sending" flag. This must be atomic hence the set_bit. */
302 sl_lock(struct slip *sl)
304 netif_stop_queue(sl->dev);
308 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
310 sl_unlock(struct slip *sl)
312 netif_wake_queue(sl->dev);
315 /* Send one completely decapsulated IP datagram to the IP layer. */
317 sl_bump(struct slip *sl)
323 #ifdef SL_INCLUDE_CSLIP
324 if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
326 if ((c = sl->rbuff[0]) & SL_TYPE_COMPRESSED_TCP) {
327 /* ignore compressed packets when CSLIP is off */
328 if (!(sl->mode & SL_MODE_CSLIP)) {
329 printk(KERN_WARNING "%s: compressed packet ignored\n", sl->dev->name);
332 /* make sure we've reserved enough space for uncompress to use */
333 if (count + 80 > sl->buffsize) {
334 sl->rx_over_errors++;
337 count = slhc_uncompress(sl->slcomp, sl->rbuff, count);
341 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {
342 if (!(sl->mode & SL_MODE_CSLIP)) {
343 /* turn on header compression */
344 sl->mode |= SL_MODE_CSLIP;
345 sl->mode &= ~SL_MODE_ADAPTIVE;
346 printk(KERN_INFO "%s: header compression turned on\n", sl->dev->name);
348 sl->rbuff[0] &= 0x4f;
349 if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0) {
354 #endif /* SL_INCLUDE_CSLIP */
358 skb = dev_alloc_skb(count);
360 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", sl->dev->name);
365 memcpy(skb_put(skb,count), sl->rbuff, count);
366 skb->mac.raw=skb->data;
367 skb->protocol=htons(ETH_P_IP);
369 sl->dev->last_rx = jiffies;
373 /* Encapsulate one IP datagram and stuff into a TTY queue. */
375 sl_encaps(struct slip *sl, unsigned char *icp, int len)
380 if (len > sl->mtu) { /* Sigh, shouldn't occur BUT ... */
381 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name);
388 #ifdef SL_INCLUDE_CSLIP
389 if (sl->mode & SL_MODE_CSLIP) {
390 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);
393 #ifdef CONFIG_SLIP_MODE_SLIP6
394 if(sl->mode & SL_MODE_SLIP6)
395 count = slip_esc6(p, (unsigned char *) sl->xbuff, len);
398 count = slip_esc(p, (unsigned char *) sl->xbuff, len);
400 /* Order of next two lines is *very* important.
401 * When we are sending a little amount of data,
402 * the transfer may be completed inside driver.write()
403 * routine, because it's running with interrupts enabled.
404 * In this case we *never* got WRITE_WAKEUP event,
405 * if we did not request it before write operation.
406 * 14 Oct 1994 Dmitry Gorodchanin.
408 sl->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
409 actual = sl->tty->driver->write(sl->tty, sl->xbuff, count);
410 #ifdef SL_CHECK_TRANSMIT
411 sl->dev->trans_start = jiffies;
413 sl->xleft = count - actual;
414 sl->xhead = sl->xbuff + actual;
415 #ifdef CONFIG_SLIP_SMART
417 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
422 * Called by the driver when there's room for more data. If we have
423 * more packets to send, we send them here.
425 static void slip_write_wakeup(struct tty_struct *tty)
428 struct slip *sl = (struct slip *) tty->disc_data;
430 /* First make sure we're connected. */
431 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) {
434 if (sl->xleft <= 0) {
435 /* Now serial buffer is almost free & we can start
436 * transmission of another packet */
438 tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
443 actual = tty->driver->write(tty, sl->xhead, sl->xleft);
448 static void sl_tx_timeout(struct net_device *dev)
450 struct slip *sl = netdev_priv(dev);
452 spin_lock(&sl->lock);
454 if (netif_queue_stopped(dev)) {
455 if (!netif_running(dev))
458 /* May be we must check transmitter timeout here ?
459 * 14 Oct 1994 Dmitry Gorodchanin.
461 #ifdef SL_CHECK_TRANSMIT
462 if (time_before(jiffies, dev->trans_start + 20 * HZ)) {
463 /* 20 sec timeout not reached */
466 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
467 (sl->tty->driver->chars_in_buffer(sl->tty) || sl->xleft) ?
468 "bad line quality" : "driver error");
470 sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
476 spin_unlock(&sl->lock);
480 /* Encapsulate an IP datagram and kick it into a TTY queue. */
482 sl_xmit(struct sk_buff *skb, struct net_device *dev)
484 struct slip *sl = netdev_priv(dev);
486 spin_lock(&sl->lock);
487 if (!netif_running(dev)) {
488 spin_unlock(&sl->lock);
489 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
493 if (sl->tty == NULL) {
494 spin_unlock(&sl->lock);
500 sl->tx_bytes+=skb->len;
501 sl_encaps(sl, skb->data, skb->len);
502 spin_unlock(&sl->lock);
509 /******************************************
510 * Routines looking at netdevice side.
511 ******************************************/
513 /* Netdevice UP -> DOWN routine */
516 sl_close(struct net_device *dev)
518 struct slip *sl = netdev_priv(dev);
520 spin_lock_bh(&sl->lock);
522 /* TTY discipline is running. */
523 sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
525 netif_stop_queue(dev);
528 spin_unlock_bh(&sl->lock);
533 /* Netdevice DOWN -> UP routine */
535 static int sl_open(struct net_device *dev)
537 struct slip *sl = netdev_priv(dev);
542 sl->flags &= (1 << SLF_INUSE);
543 netif_start_queue(dev);
547 /* Netdevice change MTU request */
549 static int sl_change_mtu(struct net_device *dev, int new_mtu)
551 struct slip *sl = netdev_priv(dev);
553 if (new_mtu < 68 || new_mtu > 65534)
556 if (new_mtu != dev->mtu)
557 return sl_realloc_bufs(sl, new_mtu);
561 /* Netdevice get statistics request */
563 static struct net_device_stats *
564 sl_get_stats(struct net_device *dev)
566 static struct net_device_stats stats;
567 struct slip *sl = netdev_priv(dev);
568 #ifdef SL_INCLUDE_CSLIP
569 struct slcompress *comp;
572 memset(&stats, 0, sizeof(struct net_device_stats));
574 stats.rx_packets = sl->rx_packets;
575 stats.tx_packets = sl->tx_packets;
576 stats.rx_bytes = sl->rx_bytes;
577 stats.tx_bytes = sl->tx_bytes;
578 stats.rx_dropped = sl->rx_dropped;
579 stats.tx_dropped = sl->tx_dropped;
580 stats.tx_errors = sl->tx_errors;
581 stats.rx_errors = sl->rx_errors;
582 stats.rx_over_errors = sl->rx_over_errors;
583 #ifdef SL_INCLUDE_CSLIP
584 stats.rx_fifo_errors = sl->rx_compressed;
585 stats.tx_fifo_errors = sl->tx_compressed;
586 stats.collisions = sl->tx_misses;
589 stats.rx_fifo_errors += comp->sls_i_compressed;
590 stats.rx_dropped += comp->sls_i_tossed;
591 stats.tx_fifo_errors += comp->sls_o_compressed;
592 stats.collisions += comp->sls_o_misses;
594 #endif /* CONFIG_INET */
598 /* Netdevice register callback */
600 static int sl_init(struct net_device *dev)
602 struct slip *sl = netdev_priv(dev);
605 * Finish setting up the DEVICE info.
609 dev->type = ARPHRD_SLIP + sl->mode;
610 #ifdef SL_CHECK_TRANSMIT
611 dev->tx_timeout = sl_tx_timeout;
612 dev->watchdog_timeo = 20*HZ;
618 static void sl_uninit(struct net_device *dev)
620 struct slip *sl = netdev_priv(dev);
625 static void sl_setup(struct net_device *dev)
628 dev->uninit = sl_uninit;
630 dev->destructor = free_netdev;
631 dev->stop = sl_close;
632 dev->get_stats = sl_get_stats;
633 dev->change_mtu = sl_change_mtu;
634 dev->hard_start_xmit = sl_xmit;
635 #ifdef CONFIG_SLIP_SMART
636 dev->do_ioctl = sl_ioctl;
638 dev->hard_header_len = 0;
640 dev->tx_queue_len = 10;
642 SET_MODULE_OWNER(dev);
644 /* New-style flags. */
645 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
648 /******************************************
649 Routines looking at TTY side.
650 ******************************************/
653 static int slip_receive_room(struct tty_struct *tty)
655 return 65536; /* We can handle an infinite amount of data. :-) */
659 * Handle the 'receiver data ready' interrupt.
660 * This function is called by the 'tty_io' module in the kernel when
661 * a block of SLIP data has been received, which can now be decapsulated
662 * and sent on to some IP layer for further processing. This will not
663 * be re-entered while running but other ldisc functions may be called
667 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, char *fp, int count)
669 struct slip *sl = (struct slip *) tty->disc_data;
671 if (!sl || sl->magic != SLIP_MAGIC ||
672 !netif_running(sl->dev))
675 /* Read the characters out of the buffer */
678 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) {
684 #ifdef CONFIG_SLIP_MODE_SLIP6
685 if (sl->mode & SL_MODE_SLIP6)
686 slip_unesc6(sl, *cp++);
689 slip_unesc(sl, *cp++);
693 /************************************
694 * slip_open helper routines.
695 ************************************/
697 /* Collect hanged up channels */
699 static void sl_sync(void)
702 struct net_device *dev;
705 for (i = 0; i < slip_maxdev; i++) {
706 if ((dev = slip_devs[i]) == NULL)
709 sl = netdev_priv(dev);
710 if (sl->tty || sl->leased)
712 if (dev->flags&IFF_UP)
718 /* Find a free SLIP channel, and link in this `tty' line. */
725 struct net_device *dev = NULL;
728 if (slip_devs == NULL)
729 return NULL; /* Master array missing ! */
731 for (i = 0; i < slip_maxdev; i++) {
736 sl = netdev_priv(dev);
738 if (sl->line != line)
743 /* Clear ESCAPE & ERROR flags */
744 sl->flags &= (1 << SLF_INUSE);
751 if (current->pid == sl->pid) {
752 if (sl->line == line && score < 3) {
763 if (sl->line == line && score < 1) {
778 sl = netdev_priv(dev);
779 sl->flags &= (1 << SLF_INUSE);
784 /* Sorry, too many, all slots in use */
785 if (i >= slip_maxdev)
789 sl = netdev_priv(dev);
790 if (test_bit(SLF_INUSE, &sl->flags)) {
791 unregister_netdevice(dev);
799 sprintf(name, "sl%d", i);
801 dev = alloc_netdev(sizeof(*sl), name, sl_setup);
807 sl = netdev_priv(dev);
809 /* Initialize channel control data */
810 sl->magic = SLIP_MAGIC;
812 spin_lock_init(&sl->lock);
813 sl->mode = SL_MODE_DEFAULT;
814 #ifdef CONFIG_SLIP_SMART
815 init_timer(&sl->keepalive_timer); /* initialize timer_list struct */
816 sl->keepalive_timer.data=(unsigned long)sl;
817 sl->keepalive_timer.function=sl_keepalive;
818 init_timer(&sl->outfill_timer);
819 sl->outfill_timer.data=(unsigned long)sl;
820 sl->outfill_timer.function=sl_outfill;
828 * Open the high-level part of the SLIP channel.
829 * This function is called by the TTY module when the
830 * SLIP line discipline is called for. Because we are
831 * sure the tty line exists, we only have to link it to
832 * a free SLIP channel...
834 * Called in process context serialized from other ldisc calls.
837 static int slip_open(struct tty_struct *tty)
842 if(!capable(CAP_NET_ADMIN))
845 /* RTnetlink lock is misused here to serialize concurrent
846 opens of slip channels. There are better ways, but it is
851 /* Collect hanged up channels. */
854 sl = (struct slip *) tty->disc_data;
857 /* First make sure we're not already connected. */
858 if (sl && sl->magic == SLIP_MAGIC)
861 /* OK. Find a free SLIP channel to use. */
863 if ((sl = sl_alloc(tty_devnum(tty))) == NULL)
868 sl->line = tty_devnum(tty);
869 sl->pid = current->pid;
871 /* FIXME: already done before we were called - seems this can go */
872 if (tty->driver->flush_buffer)
873 tty->driver->flush_buffer(tty);
875 if (!test_bit(SLF_INUSE, &sl->flags)) {
876 /* Perform the low-level SLIP initialization. */
877 if ((err = sl_alloc_bufs(sl, SL_MTU)) != 0)
880 set_bit(SLF_INUSE, &sl->flags);
882 if ((err = register_netdevice(sl->dev)))
886 #ifdef CONFIG_SLIP_SMART
888 sl->keepalive_timer.expires=jiffies+sl->keepalive*HZ;
889 add_timer (&sl->keepalive_timer);
892 sl->outfill_timer.expires=jiffies+sl->outfill*HZ;
893 add_timer (&sl->outfill_timer);
897 /* Done. We have linked the TTY line to a channel. */
899 return sl->dev->base_addr;
906 tty->disc_data = NULL;
907 clear_bit(SLF_INUSE, &sl->flags);
912 /* Count references from TTY module */
918 FIXME: 1,2 are fixed 3 was never true anyway.
920 Let me to blame a bit.
921 1. TTY module calls this funstion on soft interrupt.
922 2. TTY module calls this function WITH MASKED INTERRUPTS!
923 3. TTY module does not notify us about line discipline
926 Seems, now it is clean. The solution is to consider netdevice and
927 line discipline sides as two independent threads.
929 By-product (not desired): sl? does not feel hangups and remains open.
930 It is supposed, that user level program (dip, diald, slattach...)
931 will catch SIGHUP and make the rest of work.
933 I see no way to make more with current tty code. --ANK
937 * Close down a SLIP channel.
938 * This means flushing out any pending queues, and then returning. This
939 * call is serialized against other ldisc functions.
942 slip_close(struct tty_struct *tty)
944 struct slip *sl = (struct slip *) tty->disc_data;
946 /* First make sure we're connected. */
947 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
950 tty->disc_data = NULL;
955 /* VSV = very important to remove timers */
956 #ifdef CONFIG_SLIP_SMART
957 del_timer_sync(&sl->keepalive_timer);
958 del_timer_sync(&sl->outfill_timer);
961 /* Count references from TTY module */
964 /************************************************************************
965 * STANDARD SLIP ENCAPSULATION *
966 ************************************************************************/
969 slip_esc(unsigned char *s, unsigned char *d, int len)
971 unsigned char *ptr = d;
975 * Send an initial END character to flush out any
976 * data that may have accumulated in the receiver
983 * For each byte in the packet, send the appropriate
984 * character sequence, according to the SLIP protocol.
1006 static void slip_unesc(struct slip *sl, unsigned char s)
1011 #ifdef CONFIG_SLIP_SMART
1012 /* drop keeptest bit = VSV */
1013 if (test_bit(SLF_KEEPTEST, &sl->flags))
1014 clear_bit(SLF_KEEPTEST, &sl->flags);
1017 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2)) {
1020 clear_bit(SLF_ESCAPE, &sl->flags);
1025 set_bit(SLF_ESCAPE, &sl->flags);
1028 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) {
1033 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) {
1038 if (!test_bit(SLF_ERROR, &sl->flags)) {
1039 if (sl->rcount < sl->buffsize) {
1040 sl->rbuff[sl->rcount++] = s;
1043 sl->rx_over_errors++;
1044 set_bit(SLF_ERROR, &sl->flags);
1049 #ifdef CONFIG_SLIP_MODE_SLIP6
1050 /************************************************************************
1051 * 6 BIT SLIP ENCAPSULATION *
1052 ************************************************************************/
1055 slip_esc6(unsigned char *s, unsigned char *d, int len)
1057 unsigned char *ptr = d;
1060 unsigned short v = 0;
1064 * Send an initial END character to flush out any
1065 * data that may have accumulated in the receiver
1066 * due to line noise.
1072 * Encode the packet into printable ascii characters
1075 for (i = 0; i < len; ++i) {
1076 v = (v << 8) | s[i];
1080 c = 0x30 + ((v >> bits) & 0x3F);
1085 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1093 slip_unesc6(struct slip *sl, unsigned char s)
1098 #ifdef CONFIG_SLIP_SMART
1099 /* drop keeptest bit = VSV */
1100 if (test_bit(SLF_KEEPTEST, &sl->flags))
1101 clear_bit(SLF_KEEPTEST, &sl->flags);
1104 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2)) {
1110 } else if (s >= 0x30 && s < 0x70) {
1111 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1113 if (sl->xbits >= 8) {
1115 c = (unsigned char)(sl->xdata >> sl->xbits);
1116 if (!test_bit(SLF_ERROR, &sl->flags)) {
1117 if (sl->rcount < sl->buffsize) {
1118 sl->rbuff[sl->rcount++] = c;
1121 sl->rx_over_errors++;
1122 set_bit(SLF_ERROR, &sl->flags);
1127 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1129 /* Perform I/O control on an active SLIP channel. */
1130 static int slip_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
1132 struct slip *sl = (struct slip *) tty->disc_data;
1134 int __user *p = (int __user *)arg;
1136 /* First make sure we're connected. */
1137 if (!sl || sl->magic != SLIP_MAGIC) {
1143 tmp = strlen(sl->dev->name) + 1;
1144 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1149 if (put_user(sl->mode, p))
1154 if (get_user(tmp, p))
1156 #ifndef SL_INCLUDE_CSLIP
1157 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE)) {
1161 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1162 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
1163 /* return -EINVAL; */
1164 tmp &= ~SL_MODE_ADAPTIVE;
1167 #ifndef CONFIG_SLIP_MODE_SLIP6
1168 if (tmp & SL_MODE_SLIP6) {
1173 sl->dev->type = ARPHRD_SLIP+sl->mode;
1179 #ifdef CONFIG_SLIP_SMART
1180 /* VSV changes start here */
1181 case SIOCSKEEPALIVE:
1182 if (get_user(tmp, p))
1184 if (tmp > 255) /* max for unchar */
1187 spin_lock_bh(&sl->lock);
1189 spin_unlock_bh(&sl->lock);
1192 if ((sl->keepalive = (unchar) tmp) != 0) {
1193 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1194 set_bit(SLF_KEEPTEST, &sl->flags);
1196 del_timer (&sl->keepalive_timer);
1198 spin_unlock_bh(&sl->lock);
1201 case SIOCGKEEPALIVE:
1202 if (put_user(sl->keepalive, p))
1207 if (get_user(tmp, p))
1209 if (tmp > 255) /* max for unchar */
1211 spin_lock_bh(&sl->lock);
1213 spin_unlock_bh(&sl->lock);
1216 if ((sl->outfill = (unchar) tmp) != 0){
1217 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1218 set_bit(SLF_OUTWAIT, &sl->flags);
1220 del_timer (&sl->outfill_timer);
1222 spin_unlock_bh(&sl->lock);
1226 if (put_user(sl->outfill, p))
1229 /* VSV changes end */
1232 /* Allow stty to read, but not set, the serial port */
1235 return n_tty_ioctl(tty, file, cmd, arg);
1238 return -ENOIOCTLCMD;
1242 /* VSV changes start here */
1243 #ifdef CONFIG_SLIP_SMART
1244 /* function do_ioctl called from net/core/dev.c
1245 to allow get/set outfill/keepalive parameter
1248 static int sl_ioctl(struct net_device *dev,struct ifreq *rq,int cmd)
1250 struct slip *sl = netdev_priv(dev);
1251 unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1253 if (sl == NULL) /* Allocation failed ?? */
1256 spin_lock_bh(&sl->lock);
1259 spin_unlock_bh(&sl->lock);
1264 case SIOCSKEEPALIVE:
1265 /* max for unchar */
1266 if ((unsigned)*p > 255) {
1267 spin_unlock_bh(&sl->lock);
1270 sl->keepalive = (unchar) *p;
1271 if (sl->keepalive != 0) {
1272 sl->keepalive_timer.expires=jiffies+sl->keepalive*HZ;
1273 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1274 set_bit(SLF_KEEPTEST, &sl->flags);
1276 del_timer(&sl->keepalive_timer);
1280 case SIOCGKEEPALIVE:
1285 if ((unsigned)*p > 255) { /* max for unchar */
1286 spin_unlock_bh(&sl->lock);
1289 if ((sl->outfill = (unchar)*p) != 0){
1290 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1291 set_bit(SLF_OUTWAIT, &sl->flags);
1293 del_timer (&sl->outfill_timer);
1302 /* Resolve race condition, when ioctl'ing hanged up
1303 and opened by another process device.
1305 if (sl->tty != current->signal->tty && sl->pid != current->pid) {
1306 spin_unlock_bh(&sl->lock);
1317 spin_unlock_bh(&sl->lock);
1321 /* VSV changes end */
1323 static struct tty_ldisc sl_ldisc = {
1324 .owner = THIS_MODULE,
1325 .magic = TTY_LDISC_MAGIC,
1328 .close = slip_close,
1329 .ioctl = slip_ioctl,
1330 .receive_buf = slip_receive_buf,
1331 .receive_room = slip_receive_room,
1332 .write_wakeup = slip_write_wakeup,
1335 static int __init slip_init(void)
1339 if (slip_maxdev < 4)
1340 slip_maxdev = 4; /* Sanity */
1342 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1343 #ifdef CONFIG_SLIP_MODE_SLIP6
1344 " (6 bit encapsulation enabled)"
1347 SLIP_VERSION, slip_maxdev );
1348 #if defined(SL_INCLUDE_CSLIP)
1349 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1351 #ifdef CONFIG_SLIP_SMART
1352 printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1355 slip_devs = kmalloc(sizeof(struct net_device *)*slip_maxdev, GFP_KERNEL);
1357 printk(KERN_ERR "SLIP: Can't allocate slip devices array! Uaargh! (-> No SLIP available)\n");
1361 /* Clear the pointer array, we allocate devices when we need them */
1362 memset(slip_devs, 0, sizeof(struct net_device *)*slip_maxdev);
1364 /* Fill in our line protocol discipline, and register it */
1365 if ((status = tty_register_ldisc(N_SLIP, &sl_ldisc)) != 0) {
1366 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1372 static void __exit slip_exit(void)
1375 struct net_device *dev;
1377 unsigned long timeout = jiffies + HZ;
1380 if (slip_devs == NULL)
1383 /* First of all: check for active disciplines and hangup them.
1387 msleep_interruptible(100);
1390 for (i = 0; i < slip_maxdev; i++) {
1394 sl = netdev_priv(dev);
1395 spin_lock_bh(&sl->lock);
1398 tty_hangup(sl->tty);
1400 spin_unlock_bh(&sl->lock);
1402 } while (busy && time_before(jiffies, timeout));
1405 for (i = 0; i < slip_maxdev; i++) {
1409 slip_devs[i] = NULL;
1411 sl = netdev_priv(dev);
1413 printk(KERN_ERR "%s: tty discipline still running\n",
1415 /* Intentionally leak the control block. */
1416 dev->destructor = NULL;
1419 unregister_netdev(dev);
1425 if ((i = tty_unregister_ldisc(N_SLIP)))
1427 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1431 module_init(slip_init);
1432 module_exit(slip_exit);
1434 #ifdef CONFIG_SLIP_SMART
1436 * This is start of the code for multislip style line checking
1437 * added by Stanislav Voronyi. All changes before marked VSV
1440 static void sl_outfill(unsigned long sls)
1442 struct slip *sl=(struct slip *)sls;
1444 spin_lock(&sl->lock);
1446 if (sl->tty == NULL)
1451 if( test_bit(SLF_OUTWAIT, &sl->flags) )
1453 /* no packets were transmitted, do outfill */
1454 #ifdef CONFIG_SLIP_MODE_SLIP6
1455 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1457 unsigned char s = END;
1459 /* put END into tty queue. Is it right ??? */
1460 if (!netif_queue_stopped(sl->dev))
1462 /* if device busy no outfill */
1463 sl->tty->driver->write(sl->tty, &s, 1);
1467 set_bit(SLF_OUTWAIT, &sl->flags);
1469 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1472 spin_unlock(&sl->lock);
1475 static void sl_keepalive(unsigned long sls)
1477 struct slip *sl=(struct slip *)sls;
1479 spin_lock(&sl->lock);
1481 if (sl->tty == NULL)
1486 if(test_bit(SLF_KEEPTEST, &sl->flags))
1488 /* keepalive still high :(, we must hangup */
1489 if( sl->outfill ) /* outfill timer must be deleted too */
1490 (void)del_timer(&sl->outfill_timer);
1491 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1492 tty_hangup(sl->tty); /* this must hangup tty & close slip */
1493 /* I think we need not something else */
1497 set_bit(SLF_KEEPTEST, &sl->flags);
1499 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1503 spin_unlock(&sl->lock);
1507 MODULE_LICENSE("GPL");
1508 MODULE_ALIAS_LDISC(N_SLIP);