1 // SPDX-License-Identifier: GPL-2.0-only
3 * slip.c This module implements the SLIP protocol for kernel-based
4 * devices like TTY. It interfaces between a raw TTY, and the
5 * kernel's INET protocol layers.
7 * Version: @(#)slip.c 0.8.3 12/24/94
9 * Authors: Laurence Culhane, <loz@holmes.demon.co.uk>
10 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
13 * Alan Cox : Sanity checks and avoid tx overruns.
14 * Has a new sl->mtu field.
15 * Alan Cox : Found cause of overrun. ifconfig sl0
16 * mtu upwards. Driver now spots this
17 * and grows/shrinks its buffers(hack!).
18 * Memory leak if you run out of memory
19 * setting up a slip driver fixed.
20 * Matt Dillon : Printable slip (borrowed from NET2E)
21 * Pauline Middelink : Slip driver fixes.
22 * Alan Cox : Honours the old SL_COMPRESSED flag
23 * Alan Cox : KISS AX.25 and AXUI IP support
24 * Michael Riepe : Automatic CSLIP recognition added
25 * Charles Hedrick : CSLIP header length problem fix.
26 * Alan Cox : Corrected non-IP cases of the above.
27 * Alan Cox : Now uses hardware type as per FvK.
28 * Alan Cox : Default to 192.168.0.0 (RFC 1597)
29 * A.N.Kuznetsov : dev_tint() recursion fix.
30 * Dmitry Gorodchanin : SLIP memory leaks
31 * Dmitry Gorodchanin : Code cleanup. Reduce tty driver
32 * buffering from 4096 to 256 bytes.
33 * Improving SLIP response time.
34 * CONFIG_SLIP_MODE_SLIP6.
35 * ifconfig sl? up & down now works
38 * Alan Cox : Oops - fix AX.25 buffer lengths
39 * Dmitry Gorodchanin : Even more cleanups. Preserve CSLIP
40 * statistics. Include CSLIP code only
41 * if it really needed.
42 * Alan Cox : Free slhc buffers in the right place.
43 * Alan Cox : Allow for digipeated IP over AX.25
44 * Matti Aarnio : Dynamic SLIP devices, with ideas taken
45 * from Jim Freeman's <jfree@caldera.com>
46 * dynamic PPP devices. We do NOT kfree()
47 * device entries, just reg./unreg. them
48 * as they are needed. We kfree() them
50 * With MODULE-loading ``insmod'', user
51 * can issue parameter: slip_maxdev=1024
52 * (Or how much he/she wants.. Default
54 * Stanislav Voronyi : Slip line checking, with ideas taken
55 * from multislip BSDI driver which was
56 * written by Igor Chechik, RELCOM Corp.
57 * Only algorithms have been ported to
59 * Vitaly E. Lavrov : Sane behaviour on tty hangup.
60 * Alexey Kuznetsov : Cleanup interfaces to tty & netdevice
64 #define SL_CHECK_TRANSMIT
65 #include <linux/module.h>
66 #include <linux/moduleparam.h>
68 #include <linux/uaccess.h>
69 #include <linux/bitops.h>
70 #include <linux/sched/signal.h>
71 #include <linux/string.h>
73 #include <linux/interrupt.h>
75 #include <linux/tty.h>
76 #include <linux/errno.h>
77 #include <linux/netdevice.h>
78 #include <linux/etherdevice.h>
79 #include <linux/skbuff.h>
80 #include <linux/rtnetlink.h>
81 #include <linux/if_arp.h>
82 #include <linux/if_slip.h>
83 #include <linux/delay.h>
84 #include <linux/init.h>
85 #include <linux/slab.h>
86 #include <linux/workqueue.h>
90 #include <linux/tcp.h>
91 #include <net/slhc_vj.h>
94 #define SLIP_VERSION "0.8.4-NET3.019-NEWTTY"
96 static struct net_device **slip_devs;
98 static int slip_maxdev = SL_NRUNIT;
99 module_param(slip_maxdev, int, 0);
100 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
102 static int slip_esc(unsigned char *p, unsigned char *d, int len);
103 static void slip_unesc(struct slip *sl, unsigned char c);
104 #ifdef CONFIG_SLIP_MODE_SLIP6
105 static int slip_esc6(unsigned char *p, unsigned char *d, int len);
106 static void slip_unesc6(struct slip *sl, unsigned char c);
108 #ifdef CONFIG_SLIP_SMART
109 static void sl_keepalive(struct timer_list *t);
110 static void sl_outfill(struct timer_list *t);
111 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
114 /********************************
115 * Buffer administration routines:
120 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because
121 * sl_realloc_bufs provides strong atomicity and reallocation
122 * on actively running device.
123 *********************************/
126 Allocate channel buffers.
129 static int sl_alloc_bufs(struct slip *sl, int mtu)
135 #ifdef SL_INCLUDE_CSLIP
137 struct slcompress *slcomp = NULL;
141 * Allocate the SLIP frame buffers:
143 * rbuff Receive buffer.
144 * xbuff Transmit buffer.
145 * cbuff Temporary compression buffer.
150 * allow for arrival of larger UDP packets, even if we say not to
151 * also fixes a bug in which SunOS sends 512-byte packets even with
156 rbuff = kmalloc(len + 4, GFP_KERNEL);
159 xbuff = kmalloc(len + 4, GFP_KERNEL);
162 #ifdef SL_INCLUDE_CSLIP
163 cbuff = kmalloc(len + 4, GFP_KERNEL);
166 slcomp = slhc_init(16, 16);
170 spin_lock_bh(&sl->lock);
171 if (sl->tty == NULL) {
172 spin_unlock_bh(&sl->lock);
180 rbuff = xchg(&sl->rbuff, rbuff);
181 xbuff = xchg(&sl->xbuff, xbuff);
182 #ifdef SL_INCLUDE_CSLIP
183 cbuff = xchg(&sl->cbuff, cbuff);
184 slcomp = xchg(&sl->slcomp, slcomp);
186 #ifdef CONFIG_SLIP_MODE_SLIP6
190 spin_unlock_bh(&sl->lock);
195 #ifdef SL_INCLUDE_CSLIP
204 /* Free a SLIP channel buffers. */
205 static void sl_free_bufs(struct slip *sl)
207 /* Free all SLIP frame buffers. */
208 kfree(xchg(&sl->rbuff, NULL));
209 kfree(xchg(&sl->xbuff, NULL));
210 #ifdef SL_INCLUDE_CSLIP
211 kfree(xchg(&sl->cbuff, NULL));
212 slhc_free(xchg(&sl->slcomp, NULL));
217 Reallocate slip channel buffers.
220 static int sl_realloc_bufs(struct slip *sl, int mtu)
223 struct net_device *dev = sl->dev;
224 unsigned char *xbuff, *rbuff;
225 #ifdef SL_INCLUDE_CSLIP
226 unsigned char *cbuff;
231 * allow for arrival of larger UDP packets, even if we say not to
232 * also fixes a bug in which SunOS sends 512-byte packets even with
238 xbuff = kmalloc(len + 4, GFP_ATOMIC);
239 rbuff = kmalloc(len + 4, GFP_ATOMIC);
240 #ifdef SL_INCLUDE_CSLIP
241 cbuff = kmalloc(len + 4, GFP_ATOMIC);
245 #ifdef SL_INCLUDE_CSLIP
246 if (xbuff == NULL || rbuff == NULL || cbuff == NULL) {
248 if (xbuff == NULL || rbuff == NULL) {
251 printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n",
257 spin_lock_bh(&sl->lock);
263 xbuff = xchg(&sl->xbuff, xbuff);
264 rbuff = xchg(&sl->rbuff, rbuff);
265 #ifdef SL_INCLUDE_CSLIP
266 cbuff = xchg(&sl->cbuff, cbuff);
269 if (sl->xleft <= len) {
270 memcpy(sl->xbuff, sl->xhead, sl->xleft);
273 dev->stats.tx_dropped++;
276 sl->xhead = sl->xbuff;
279 if (sl->rcount <= len) {
280 memcpy(sl->rbuff, rbuff, sl->rcount);
283 dev->stats.rx_over_errors++;
284 set_bit(SLF_ERROR, &sl->flags);
293 spin_unlock_bh(&sl->lock);
298 #ifdef SL_INCLUDE_CSLIP
305 /* Set the "sending" flag. This must be atomic hence the set_bit. */
306 static inline void sl_lock(struct slip *sl)
308 netif_stop_queue(sl->dev);
312 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
313 static inline void sl_unlock(struct slip *sl)
315 netif_wake_queue(sl->dev);
318 /* Send one completely decapsulated IP datagram to the IP layer. */
319 static void sl_bump(struct slip *sl)
321 struct net_device *dev = sl->dev;
326 #ifdef SL_INCLUDE_CSLIP
327 if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
328 unsigned char c = sl->rbuff[0];
329 if (c & SL_TYPE_COMPRESSED_TCP) {
330 /* ignore compressed packets when CSLIP is off */
331 if (!(sl->mode & SL_MODE_CSLIP)) {
332 printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name);
335 /* make sure we've reserved enough space for uncompress
337 if (count + 80 > sl->buffsize) {
338 dev->stats.rx_over_errors++;
341 count = slhc_uncompress(sl->slcomp, sl->rbuff, count);
344 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {
345 if (!(sl->mode & SL_MODE_CSLIP)) {
346 /* turn on header compression */
347 sl->mode |= SL_MODE_CSLIP;
348 sl->mode &= ~SL_MODE_ADAPTIVE;
349 printk(KERN_INFO "%s: header compression turned on\n", dev->name);
351 sl->rbuff[0] &= 0x4f;
352 if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0)
356 #endif /* SL_INCLUDE_CSLIP */
358 dev->stats.rx_bytes += count;
360 skb = dev_alloc_skb(count);
362 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name);
363 dev->stats.rx_dropped++;
367 skb_put_data(skb, sl->rbuff, count);
368 skb_reset_mac_header(skb);
369 skb->protocol = htons(ETH_P_IP);
371 dev->stats.rx_packets++;
374 /* Encapsulate one IP datagram and stuff into a TTY queue. */
375 static void 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);
382 sl->dev->stats.tx_dropped++;
388 #ifdef SL_INCLUDE_CSLIP
389 if (sl->mode & SL_MODE_CSLIP)
390 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);
392 #ifdef CONFIG_SLIP_MODE_SLIP6
393 if (sl->mode & SL_MODE_SLIP6)
394 count = slip_esc6(p, sl->xbuff, len);
397 count = slip_esc(p, sl->xbuff, len);
399 /* Order of next two lines is *very* important.
400 * When we are sending a little amount of data,
401 * the transfer may be completed inside the ops->write()
402 * routine, because it's running with interrupts enabled.
403 * In this case we *never* got WRITE_WAKEUP event,
404 * if we did not request it before write operation.
405 * 14 Oct 1994 Dmitry Gorodchanin.
407 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
408 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
409 #ifdef SL_CHECK_TRANSMIT
410 netif_trans_update(sl->dev);
412 sl->xleft = count - actual;
413 sl->xhead = sl->xbuff + actual;
414 #ifdef CONFIG_SLIP_SMART
416 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
420 /* Write out any remaining transmit buffer. Scheduled when tty is writable */
421 static void slip_transmit(struct work_struct *work)
423 struct slip *sl = container_of(work, struct slip, tx_work);
426 spin_lock_bh(&sl->lock);
427 /* First make sure we're connected. */
428 if (!sl->tty || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) {
429 spin_unlock_bh(&sl->lock);
433 if (sl->xleft <= 0) {
434 /* Now serial buffer is almost free & we can start
435 * transmission of another packet */
436 sl->dev->stats.tx_packets++;
437 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
438 spin_unlock_bh(&sl->lock);
443 actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
446 spin_unlock_bh(&sl->lock);
450 * Called by the driver when there's room for more data.
451 * Schedule the transmit.
453 static void slip_write_wakeup(struct tty_struct *tty)
455 struct slip *sl = tty->disc_data;
457 schedule_work(&sl->tx_work);
460 static void sl_tx_timeout(struct net_device *dev)
462 struct slip *sl = netdev_priv(dev);
464 spin_lock(&sl->lock);
466 if (netif_queue_stopped(dev)) {
467 if (!netif_running(dev))
470 /* May be we must check transmitter timeout here ?
471 * 14 Oct 1994 Dmitry Gorodchanin.
473 #ifdef SL_CHECK_TRANSMIT
474 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) {
475 /* 20 sec timeout not reached */
478 printk(KERN_WARNING "%s: transmit timed out, %s?\n",
480 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
481 "bad line quality" : "driver error");
483 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
488 spin_unlock(&sl->lock);
492 /* Encapsulate an IP datagram and kick it into a TTY queue. */
494 sl_xmit(struct sk_buff *skb, struct net_device *dev)
496 struct slip *sl = netdev_priv(dev);
498 spin_lock(&sl->lock);
499 if (!netif_running(dev)) {
500 spin_unlock(&sl->lock);
501 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
505 if (sl->tty == NULL) {
506 spin_unlock(&sl->lock);
512 dev->stats.tx_bytes += skb->len;
513 sl_encaps(sl, skb->data, skb->len);
514 spin_unlock(&sl->lock);
521 /******************************************
522 * Routines looking at netdevice side.
523 ******************************************/
525 /* Netdevice UP -> DOWN routine */
528 sl_close(struct net_device *dev)
530 struct slip *sl = netdev_priv(dev);
532 spin_lock_bh(&sl->lock);
534 /* TTY discipline is running. */
535 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
536 netif_stop_queue(dev);
539 spin_unlock_bh(&sl->lock);
544 /* Netdevice DOWN -> UP routine */
546 static int sl_open(struct net_device *dev)
548 struct slip *sl = netdev_priv(dev);
553 sl->flags &= (1 << SLF_INUSE);
554 netif_start_queue(dev);
558 /* Netdevice change MTU request */
560 static int sl_change_mtu(struct net_device *dev, int new_mtu)
562 struct slip *sl = netdev_priv(dev);
564 return sl_realloc_bufs(sl, new_mtu);
567 /* Netdevice get statistics request */
570 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
572 struct net_device_stats *devstats = &dev->stats;
573 #ifdef SL_INCLUDE_CSLIP
574 struct slip *sl = netdev_priv(dev);
575 struct slcompress *comp = sl->slcomp;
577 stats->rx_packets = devstats->rx_packets;
578 stats->tx_packets = devstats->tx_packets;
579 stats->rx_bytes = devstats->rx_bytes;
580 stats->tx_bytes = devstats->tx_bytes;
581 stats->rx_dropped = devstats->rx_dropped;
582 stats->tx_dropped = devstats->tx_dropped;
583 stats->tx_errors = devstats->tx_errors;
584 stats->rx_errors = devstats->rx_errors;
585 stats->rx_over_errors = devstats->rx_over_errors;
587 #ifdef SL_INCLUDE_CSLIP
589 /* Generic compressed statistics */
590 stats->rx_compressed = comp->sls_i_compressed;
591 stats->tx_compressed = comp->sls_o_compressed;
593 /* Are we really still needs this? */
594 stats->rx_fifo_errors += comp->sls_i_compressed;
595 stats->rx_dropped += comp->sls_i_tossed;
596 stats->tx_fifo_errors += comp->sls_o_compressed;
597 stats->collisions += comp->sls_o_misses;
602 /* Netdevice register callback */
604 static int sl_init(struct net_device *dev)
606 struct slip *sl = netdev_priv(dev);
609 * Finish setting up the DEVICE info.
613 dev->type = ARPHRD_SLIP + sl->mode;
614 #ifdef SL_CHECK_TRANSMIT
615 dev->watchdog_timeo = 20*HZ;
621 static void sl_uninit(struct net_device *dev)
623 struct slip *sl = netdev_priv(dev);
628 /* Hook the destructor so we can free slip devices at the right point in time */
629 static void sl_free_netdev(struct net_device *dev)
631 int i = dev->base_addr;
636 static const struct net_device_ops sl_netdev_ops = {
638 .ndo_uninit = sl_uninit,
640 .ndo_stop = sl_close,
641 .ndo_start_xmit = sl_xmit,
642 .ndo_get_stats64 = sl_get_stats64,
643 .ndo_change_mtu = sl_change_mtu,
644 .ndo_tx_timeout = sl_tx_timeout,
645 #ifdef CONFIG_SLIP_SMART
646 .ndo_do_ioctl = sl_ioctl,
651 static void sl_setup(struct net_device *dev)
653 dev->netdev_ops = &sl_netdev_ops;
654 dev->needs_free_netdev = true;
655 dev->priv_destructor = sl_free_netdev;
657 dev->hard_header_len = 0;
659 dev->tx_queue_len = 10;
661 /* MTU range: 68 - 65534 */
663 dev->max_mtu = 65534;
665 /* New-style flags. */
666 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
669 /******************************************
670 Routines looking at TTY side.
671 ******************************************/
675 * Handle the 'receiver data ready' interrupt.
676 * This function is called by the 'tty_io' module in the kernel when
677 * a block of SLIP data has been received, which can now be decapsulated
678 * and sent on to some IP layer for further processing. This will not
679 * be re-entered while running but other ldisc functions may be called
683 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
686 struct slip *sl = tty->disc_data;
688 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
691 /* Read the characters out of the buffer */
694 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
695 sl->dev->stats.rx_errors++;
699 #ifdef CONFIG_SLIP_MODE_SLIP6
700 if (sl->mode & SL_MODE_SLIP6)
701 slip_unesc6(sl, *cp++);
704 slip_unesc(sl, *cp++);
708 /************************************
709 * slip_open helper routines.
710 ************************************/
712 /* Collect hanged up channels */
713 static void sl_sync(void)
716 struct net_device *dev;
719 for (i = 0; i < slip_maxdev; i++) {
724 sl = netdev_priv(dev);
725 if (sl->tty || sl->leased)
727 if (dev->flags & IFF_UP)
733 /* Find a free SLIP channel, and link in this `tty' line. */
734 static struct slip *sl_alloc(void)
738 struct net_device *dev = NULL;
741 for (i = 0; i < slip_maxdev; i++) {
746 /* Sorry, too many, all slots in use */
747 if (i >= slip_maxdev)
750 sprintf(name, "sl%d", i);
751 dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup);
756 sl = netdev_priv(dev);
758 /* Initialize channel control data */
759 sl->magic = SLIP_MAGIC;
761 spin_lock_init(&sl->lock);
762 INIT_WORK(&sl->tx_work, slip_transmit);
763 sl->mode = SL_MODE_DEFAULT;
764 #ifdef CONFIG_SLIP_SMART
765 /* initialize timer_list struct */
766 timer_setup(&sl->keepalive_timer, sl_keepalive, 0);
767 timer_setup(&sl->outfill_timer, sl_outfill, 0);
774 * Open the high-level part of the SLIP channel.
775 * This function is called by the TTY module when the
776 * SLIP line discipline is called for. Because we are
777 * sure the tty line exists, we only have to link it to
778 * a free SLIP channel...
780 * Called in process context serialized from other ldisc calls.
783 static int slip_open(struct tty_struct *tty)
788 if (!capable(CAP_NET_ADMIN))
791 if (tty->ops->write == NULL)
794 /* RTnetlink lock is misused here to serialize concurrent
795 opens of slip channels. There are better ways, but it is
800 /* Collect hanged up channels. */
806 /* First make sure we're not already connected. */
807 if (sl && sl->magic == SLIP_MAGIC)
810 /* OK. Find a free SLIP channel to use. */
818 sl->pid = current->pid;
820 if (!test_bit(SLF_INUSE, &sl->flags)) {
821 /* Perform the low-level SLIP initialization. */
822 err = sl_alloc_bufs(sl, SL_MTU);
826 set_bit(SLF_INUSE, &sl->flags);
828 err = register_netdevice(sl->dev);
833 #ifdef CONFIG_SLIP_SMART
835 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;
836 add_timer(&sl->keepalive_timer);
839 sl->outfill_timer.expires = jiffies + sl->outfill * HZ;
840 add_timer(&sl->outfill_timer);
844 /* Done. We have linked the TTY line to a channel. */
846 tty->receive_room = 65536; /* We don't flow control */
848 /* TTY layer expects 0 on success */
856 tty->disc_data = NULL;
857 clear_bit(SLF_INUSE, &sl->flags);
858 free_netdev(sl->dev);
863 /* Count references from TTY module */
868 * Close down a SLIP channel.
869 * This means flushing out any pending queues, and then returning. This
870 * call is serialized against other ldisc functions.
872 * We also use this method fo a hangup event
875 static void slip_close(struct tty_struct *tty)
877 struct slip *sl = tty->disc_data;
879 /* First make sure we're connected. */
880 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
883 spin_lock_bh(&sl->lock);
884 tty->disc_data = NULL;
886 spin_unlock_bh(&sl->lock);
888 flush_work(&sl->tx_work);
890 /* VSV = very important to remove timers */
891 #ifdef CONFIG_SLIP_SMART
892 del_timer_sync(&sl->keepalive_timer);
893 del_timer_sync(&sl->outfill_timer);
895 /* Flush network side */
896 unregister_netdev(sl->dev);
897 /* This will complete via sl_free_netdev */
900 static int slip_hangup(struct tty_struct *tty)
905 /************************************************************************
906 * STANDARD SLIP ENCAPSULATION *
907 ************************************************************************/
909 static int slip_esc(unsigned char *s, unsigned char *d, int len)
911 unsigned char *ptr = d;
915 * Send an initial END character to flush out any
916 * data that may have accumulated in the receiver
923 * For each byte in the packet, send the appropriate
924 * character sequence, according to the SLIP protocol.
946 static void slip_unesc(struct slip *sl, unsigned char s)
951 #ifdef CONFIG_SLIP_SMART
952 /* drop keeptest bit = VSV */
953 if (test_bit(SLF_KEEPTEST, &sl->flags))
954 clear_bit(SLF_KEEPTEST, &sl->flags);
957 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
960 clear_bit(SLF_ESCAPE, &sl->flags);
965 set_bit(SLF_ESCAPE, &sl->flags);
968 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
972 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
976 if (!test_bit(SLF_ERROR, &sl->flags)) {
977 if (sl->rcount < sl->buffsize) {
978 sl->rbuff[sl->rcount++] = s;
981 sl->dev->stats.rx_over_errors++;
982 set_bit(SLF_ERROR, &sl->flags);
987 #ifdef CONFIG_SLIP_MODE_SLIP6
988 /************************************************************************
989 * 6 BIT SLIP ENCAPSULATION *
990 ************************************************************************/
992 static int slip_esc6(unsigned char *s, unsigned char *d, int len)
994 unsigned char *ptr = d;
997 unsigned short v = 0;
1001 * Send an initial END character to flush out any
1002 * data that may have accumulated in the receiver
1003 * due to line noise.
1009 * Encode the packet into printable ascii characters
1012 for (i = 0; i < len; ++i) {
1013 v = (v << 8) | s[i];
1017 c = 0x30 + ((v >> bits) & 0x3F);
1022 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1029 static void slip_unesc6(struct slip *sl, unsigned char s)
1034 #ifdef CONFIG_SLIP_SMART
1035 /* drop keeptest bit = VSV */
1036 if (test_bit(SLF_KEEPTEST, &sl->flags))
1037 clear_bit(SLF_KEEPTEST, &sl->flags);
1040 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
1046 } else if (s >= 0x30 && s < 0x70) {
1047 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1049 if (sl->xbits >= 8) {
1051 c = (unsigned char)(sl->xdata >> sl->xbits);
1052 if (!test_bit(SLF_ERROR, &sl->flags)) {
1053 if (sl->rcount < sl->buffsize) {
1054 sl->rbuff[sl->rcount++] = c;
1057 sl->dev->stats.rx_over_errors++;
1058 set_bit(SLF_ERROR, &sl->flags);
1063 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1065 /* Perform I/O control on an active SLIP channel. */
1066 static int slip_ioctl(struct tty_struct *tty, struct file *file,
1067 unsigned int cmd, unsigned long arg)
1069 struct slip *sl = tty->disc_data;
1071 int __user *p = (int __user *)arg;
1073 /* First make sure we're connected. */
1074 if (!sl || sl->magic != SLIP_MAGIC)
1079 tmp = strlen(sl->dev->name) + 1;
1080 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1085 if (put_user(sl->mode, p))
1090 if (get_user(tmp, p))
1092 #ifndef SL_INCLUDE_CSLIP
1093 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
1096 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1097 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
1098 /* return -EINVAL; */
1099 tmp &= ~SL_MODE_ADAPTIVE;
1101 #ifndef CONFIG_SLIP_MODE_SLIP6
1102 if (tmp & SL_MODE_SLIP6)
1106 sl->dev->type = ARPHRD_SLIP + sl->mode;
1112 #ifdef CONFIG_SLIP_SMART
1113 /* VSV changes start here */
1114 case SIOCSKEEPALIVE:
1115 if (get_user(tmp, p))
1117 if (tmp > 255) /* max for unchar */
1120 spin_lock_bh(&sl->lock);
1122 spin_unlock_bh(&sl->lock);
1125 sl->keepalive = (u8)tmp;
1126 if (sl->keepalive != 0) {
1127 mod_timer(&sl->keepalive_timer,
1128 jiffies + sl->keepalive * HZ);
1129 set_bit(SLF_KEEPTEST, &sl->flags);
1131 del_timer(&sl->keepalive_timer);
1132 spin_unlock_bh(&sl->lock);
1135 case SIOCGKEEPALIVE:
1136 if (put_user(sl->keepalive, p))
1141 if (get_user(tmp, p))
1143 if (tmp > 255) /* max for unchar */
1145 spin_lock_bh(&sl->lock);
1147 spin_unlock_bh(&sl->lock);
1150 sl->outfill = (u8)tmp;
1151 if (sl->outfill != 0) {
1152 mod_timer(&sl->outfill_timer,
1153 jiffies + sl->outfill * HZ);
1154 set_bit(SLF_OUTWAIT, &sl->flags);
1156 del_timer(&sl->outfill_timer);
1157 spin_unlock_bh(&sl->lock);
1161 if (put_user(sl->outfill, p))
1164 /* VSV changes end */
1167 return tty_mode_ioctl(tty, file, cmd, arg);
1171 /* VSV changes start here */
1172 #ifdef CONFIG_SLIP_SMART
1173 /* function do_ioctl called from net/core/dev.c
1174 to allow get/set outfill/keepalive parameter
1177 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
1179 struct slip *sl = netdev_priv(dev);
1180 unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1182 if (sl == NULL) /* Allocation failed ?? */
1185 spin_lock_bh(&sl->lock);
1188 spin_unlock_bh(&sl->lock);
1193 case SIOCSKEEPALIVE:
1194 /* max for unchar */
1195 if ((unsigned)*p > 255) {
1196 spin_unlock_bh(&sl->lock);
1199 sl->keepalive = (u8)*p;
1200 if (sl->keepalive != 0) {
1201 sl->keepalive_timer.expires =
1202 jiffies + sl->keepalive * HZ;
1203 mod_timer(&sl->keepalive_timer,
1204 jiffies + sl->keepalive * HZ);
1205 set_bit(SLF_KEEPTEST, &sl->flags);
1207 del_timer(&sl->keepalive_timer);
1210 case SIOCGKEEPALIVE:
1215 if ((unsigned)*p > 255) { /* max for unchar */
1216 spin_unlock_bh(&sl->lock);
1219 sl->outfill = (u8)*p;
1220 if (sl->outfill != 0) {
1221 mod_timer(&sl->outfill_timer,
1222 jiffies + sl->outfill * HZ);
1223 set_bit(SLF_OUTWAIT, &sl->flags);
1225 del_timer(&sl->outfill_timer);
1233 /* Resolve race condition, when ioctl'ing hanged up
1234 and opened by another process device.
1236 if (sl->tty != current->signal->tty &&
1237 sl->pid != current->pid) {
1238 spin_unlock_bh(&sl->lock);
1249 spin_unlock_bh(&sl->lock);
1253 /* VSV changes end */
1255 static struct tty_ldisc_ops sl_ldisc = {
1256 .owner = THIS_MODULE,
1257 .magic = TTY_LDISC_MAGIC,
1260 .close = slip_close,
1261 .hangup = slip_hangup,
1262 .ioctl = slip_ioctl,
1263 .receive_buf = slip_receive_buf,
1264 .write_wakeup = slip_write_wakeup,
1267 static int __init slip_init(void)
1271 if (slip_maxdev < 4)
1272 slip_maxdev = 4; /* Sanity */
1274 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1275 #ifdef CONFIG_SLIP_MODE_SLIP6
1276 " (6 bit encapsulation enabled)"
1279 SLIP_VERSION, slip_maxdev);
1280 #if defined(SL_INCLUDE_CSLIP)
1281 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1283 #ifdef CONFIG_SLIP_SMART
1284 printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1287 slip_devs = kcalloc(slip_maxdev, sizeof(struct net_device *),
1292 /* Fill in our line protocol discipline, and register it */
1293 status = tty_register_ldisc(N_SLIP, &sl_ldisc);
1295 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1301 static void __exit slip_exit(void)
1304 struct net_device *dev;
1306 unsigned long timeout = jiffies + HZ;
1309 if (slip_devs == NULL)
1312 /* First of all: check for active disciplines and hangup them.
1316 msleep_interruptible(100);
1319 for (i = 0; i < slip_maxdev; i++) {
1323 sl = netdev_priv(dev);
1324 spin_lock_bh(&sl->lock);
1327 tty_hangup(sl->tty);
1329 spin_unlock_bh(&sl->lock);
1331 } while (busy && time_before(jiffies, timeout));
1333 /* FIXME: hangup is async so we should wait when doing this second
1336 for (i = 0; i < slip_maxdev; i++) {
1340 slip_devs[i] = NULL;
1342 sl = netdev_priv(dev);
1344 printk(KERN_ERR "%s: tty discipline still running\n",
1348 unregister_netdev(dev);
1354 i = tty_unregister_ldisc(N_SLIP);
1356 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1359 module_init(slip_init);
1360 module_exit(slip_exit);
1362 #ifdef CONFIG_SLIP_SMART
1364 * This is start of the code for multislip style line checking
1365 * added by Stanislav Voronyi. All changes before marked VSV
1368 static void sl_outfill(struct timer_list *t)
1370 struct slip *sl = from_timer(sl, t, outfill_timer);
1372 spin_lock(&sl->lock);
1374 if (sl->tty == NULL)
1378 if (test_bit(SLF_OUTWAIT, &sl->flags)) {
1379 /* no packets were transmitted, do outfill */
1380 #ifdef CONFIG_SLIP_MODE_SLIP6
1381 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1383 unsigned char s = END;
1385 /* put END into tty queue. Is it right ??? */
1386 if (!netif_queue_stopped(sl->dev)) {
1387 /* if device busy no outfill */
1388 sl->tty->ops->write(sl->tty, &s, 1);
1391 set_bit(SLF_OUTWAIT, &sl->flags);
1393 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1396 spin_unlock(&sl->lock);
1399 static void sl_keepalive(struct timer_list *t)
1401 struct slip *sl = from_timer(sl, t, keepalive_timer);
1403 spin_lock(&sl->lock);
1405 if (sl->tty == NULL)
1408 if (sl->keepalive) {
1409 if (test_bit(SLF_KEEPTEST, &sl->flags)) {
1410 /* keepalive still high :(, we must hangup */
1412 /* outfill timer must be deleted too */
1413 (void)del_timer(&sl->outfill_timer);
1414 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1415 /* this must hangup tty & close slip */
1416 tty_hangup(sl->tty);
1417 /* I think we need not something else */
1420 set_bit(SLF_KEEPTEST, &sl->flags);
1422 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1425 spin_unlock(&sl->lock);
1429 MODULE_LICENSE("GPL");
1430 MODULE_ALIAS_LDISC(N_SLIP);