Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.git] / drivers / net / slip.c
1 /*
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.
5  *
6  * Version:     @(#)slip.c      0.8.3   12/24/94
7  *
8  * Authors:     Laurence Culhane, <loz@holmes.demon.co.uk>
9  *              Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
10  *
11  * Fixes:
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
15  *                                      mtu upwards. Driver now spots this
16  *                                      and grows/shrinks its buffers(hack!).
17  *                                      Memory leak if you run out of memory
18  *                                      setting up a slip driver fixed.
19  *              Matt Dillon     :       Printable slip (borrowed from NET2E)
20  *      Pauline Middelink       :       Slip driver fixes.
21  *              Alan Cox        :       Honours the old SL_COMPRESSED flag
22  *              Alan Cox        :       KISS AX.25 and AXUI IP support
23  *              Michael Riepe   :       Automatic CSLIP recognition added
24  *              Charles Hedrick :       CSLIP header length problem fix.
25  *              Alan Cox        :       Corrected non-IP cases of the above.
26  *              Alan Cox        :       Now uses hardware type as per FvK.
27  *              Alan Cox        :       Default to 192.168.0.0 (RFC 1597)
28  *              A.N.Kuznetsov   :       dev_tint() recursion fix.
29  *      Dmitry Gorodchanin      :       SLIP memory leaks
30  *      Dmitry Gorodchanin      :       Code cleanup. Reduce tty driver
31  *                                      buffering from 4096 to 256 bytes.
32  *                                      Improving SLIP response time.
33  *                                      CONFIG_SLIP_MODE_SLIP6.
34  *                                      ifconfig sl? up & down now works
35  *                                      correctly.
36  *                                      Modularization.
37  *              Alan Cox        :       Oops - fix AX.25 buffer lengths
38  *      Dmitry Gorodchanin      :       Even more cleanups. Preserve CSLIP
39  *                                      statistics. Include CSLIP code only
40  *                                      if it really needed.
41  *              Alan Cox        :       Free slhc buffers in the right place.
42  *              Alan Cox        :       Allow for digipeated IP over AX.25
43  *              Matti Aarnio    :       Dynamic SLIP devices, with ideas taken
44  *                                      from Jim Freeman's <jfree@caldera.com>
45  *                                      dynamic PPP devices.  We do NOT kfree()
46  *                                      device entries, just reg./unreg. them
47  *                                      as they are needed.  We kfree() them
48  *                                      at module cleanup.
49  *                                      With MODULE-loading ``insmod'', user
50  *                                      can issue parameter:  slip_maxdev=1024
51  *                                      (Or how much he/she wants.. Default
52  *                                      is 256)
53  *      Stanislav Voronyi       :       Slip line checking, with ideas taken
54  *                                      from multislip BSDI driver which was
55  *                                      written by Igor Chechik, RELCOM Corp.
56  *                                      Only algorithms have been ported to
57  *                                      Linux SLIP driver.
58  *      Vitaly E. Lavrov        :       Sane behaviour on tty hangup.
59  *      Alexey Kuznetsov        :       Cleanup interfaces to tty & netdevice
60  *                                      modules.
61  */
62
63 #define SL_CHECK_TRANSMIT
64 #include <linux/module.h>
65 #include <linux/moduleparam.h>
66
67 #include <asm/system.h>
68 #include <asm/uaccess.h>
69 #include <linux/bitops.h>
70 #include <linux/sched.h>
71 #include <linux/string.h>
72 #include <linux/mm.h>
73 #include <linux/interrupt.h>
74 #include <linux/in.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/compat.h>
84 #include <linux/delay.h>
85 #include <linux/init.h>
86 #include "slip.h"
87 #ifdef CONFIG_INET
88 #include <linux/ip.h>
89 #include <linux/tcp.h>
90 #include <net/slhc_vj.h>
91 #endif
92
93 #define SLIP_VERSION    "0.8.4-NET3.019-NEWTTY"
94
95 static struct net_device **slip_devs;
96
97 static int slip_maxdev = SL_NRUNIT;
98 module_param(slip_maxdev, int, 0);
99 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
100
101 static int slip_esc(unsigned char *p, unsigned char *d, int len);
102 static void slip_unesc(struct slip *sl, unsigned char c);
103 #ifdef CONFIG_SLIP_MODE_SLIP6
104 static int slip_esc6(unsigned char *p, unsigned char *d, int len);
105 static void slip_unesc6(struct slip *sl, unsigned char c);
106 #endif
107 #ifdef CONFIG_SLIP_SMART
108 static void sl_keepalive(unsigned long sls);
109 static void sl_outfill(unsigned long sls);
110 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
111 #endif
112
113 /********************************
114 *  Buffer administration routines:
115 *       sl_alloc_bufs()
116 *       sl_free_bufs()
117 *       sl_realloc_bufs()
118 *
119 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because
120 *       sl_realloc_bufs provides strong atomicity and reallocation
121 *       on actively running device.
122 *********************************/
123
124 /*
125    Allocate channel buffers.
126  */
127
128 static int sl_alloc_bufs(struct slip *sl, int mtu)
129 {
130         int err = -ENOBUFS;
131         unsigned long len;
132         char *rbuff = NULL;
133         char *xbuff = NULL;
134 #ifdef SL_INCLUDE_CSLIP
135         char *cbuff = NULL;
136         struct slcompress *slcomp = NULL;
137 #endif
138
139         /*
140          * Allocate the SLIP frame buffers:
141          *
142          * rbuff        Receive buffer.
143          * xbuff        Transmit buffer.
144          * cbuff        Temporary compression buffer.
145          */
146         len = mtu * 2;
147
148         /*
149          * allow for arrival of larger UDP packets, even if we say not to
150          * also fixes a bug in which SunOS sends 512-byte packets even with
151          * an MSS of 128
152          */
153         if (len < 576 * 2)
154                 len = 576 * 2;
155         rbuff = kmalloc(len + 4, GFP_KERNEL);
156         if (rbuff == NULL)
157                 goto err_exit;
158         xbuff = kmalloc(len + 4, GFP_KERNEL);
159         if (xbuff == NULL)
160                 goto err_exit;
161 #ifdef SL_INCLUDE_CSLIP
162         cbuff = kmalloc(len + 4, GFP_KERNEL);
163         if (cbuff == NULL)
164                 goto err_exit;
165         slcomp = slhc_init(16, 16);
166         if (slcomp == NULL)
167                 goto err_exit;
168 #endif
169         spin_lock_bh(&sl->lock);
170         if (sl->tty == NULL) {
171                 spin_unlock_bh(&sl->lock);
172                 err = -ENODEV;
173                 goto err_exit;
174         }
175         sl->mtu      = mtu;
176         sl->buffsize = len;
177         sl->rcount   = 0;
178         sl->xleft    = 0;
179         rbuff = xchg(&sl->rbuff, rbuff);
180         xbuff = xchg(&sl->xbuff, xbuff);
181 #ifdef SL_INCLUDE_CSLIP
182         cbuff = xchg(&sl->cbuff, cbuff);
183         slcomp = xchg(&sl->slcomp, slcomp);
184 #ifdef CONFIG_SLIP_MODE_SLIP6
185         sl->xdata    = 0;
186         sl->xbits    = 0;
187 #endif
188 #endif
189         spin_unlock_bh(&sl->lock);
190         err = 0;
191
192         /* Cleanup */
193 err_exit:
194 #ifdef SL_INCLUDE_CSLIP
195         kfree(cbuff);
196         if (slcomp)
197                 slhc_free(slcomp);
198 #endif
199         kfree(xbuff);
200         kfree(rbuff);
201         return err;
202 }
203
204 /* Free a SLIP channel buffers. */
205 static void sl_free_bufs(struct slip *sl)
206 {
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));
213 #endif
214 }
215
216 /*
217    Reallocate slip channel buffers.
218  */
219
220 static int sl_realloc_bufs(struct slip *sl, int mtu)
221 {
222         int err = 0;
223         struct net_device *dev = sl->dev;
224         unsigned char *xbuff, *rbuff;
225 #ifdef SL_INCLUDE_CSLIP
226         unsigned char *cbuff;
227 #endif
228         int len = mtu * 2;
229
230 /*
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
233  * an MSS of 128
234  */
235         if (len < 576 * 2)
236                 len = 576 * 2;
237
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);
242 #endif
243
244
245 #ifdef SL_INCLUDE_CSLIP
246         if (xbuff == NULL || rbuff == NULL || cbuff == NULL)  {
247 #else
248         if (xbuff == NULL || rbuff == NULL)  {
249 #endif
250                 if (mtu >= sl->mtu) {
251                         printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n",
252                                dev->name);
253                         err = -ENOBUFS;
254                 }
255                 goto done;
256         }
257         spin_lock_bh(&sl->lock);
258
259         err = -ENODEV;
260         if (sl->tty == NULL)
261                 goto done_on_bh;
262
263         xbuff    = xchg(&sl->xbuff, xbuff);
264         rbuff    = xchg(&sl->rbuff, rbuff);
265 #ifdef SL_INCLUDE_CSLIP
266         cbuff    = xchg(&sl->cbuff, cbuff);
267 #endif
268         if (sl->xleft)  {
269                 if (sl->xleft <= len)  {
270                         memcpy(sl->xbuff, sl->xhead, sl->xleft);
271                 } else  {
272                         sl->xleft = 0;
273                         sl->tx_dropped++;
274                 }
275         }
276         sl->xhead = sl->xbuff;
277
278         if (sl->rcount)  {
279                 if (sl->rcount <= len) {
280                         memcpy(sl->rbuff, rbuff, sl->rcount);
281                 } else  {
282                         sl->rcount = 0;
283                         sl->rx_over_errors++;
284                         set_bit(SLF_ERROR, &sl->flags);
285                 }
286         }
287         sl->mtu      = mtu;
288         dev->mtu      = mtu;
289         sl->buffsize = len;
290         err = 0;
291
292 done_on_bh:
293         spin_unlock_bh(&sl->lock);
294
295 done:
296         kfree(xbuff);
297         kfree(rbuff);
298 #ifdef SL_INCLUDE_CSLIP
299         kfree(cbuff);
300 #endif
301         return err;
302 }
303
304
305 /* Set the "sending" flag.  This must be atomic hence the set_bit. */
306 static inline void sl_lock(struct slip *sl)
307 {
308         netif_stop_queue(sl->dev);
309 }
310
311
312 /* Clear the "sending" flag.  This must be atomic, hence the ASM. */
313 static inline void sl_unlock(struct slip *sl)
314 {
315         netif_wake_queue(sl->dev);
316 }
317
318 /* Send one completely decapsulated IP datagram to the IP layer. */
319 static void sl_bump(struct slip *sl)
320 {
321         struct sk_buff *skb;
322         int count;
323
324         count = sl->rcount;
325 #ifdef SL_INCLUDE_CSLIP
326         if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
327                 unsigned char c = sl->rbuff[0];
328                 if (c & SL_TYPE_COMPRESSED_TCP) {
329                         /* ignore compressed packets when CSLIP is off */
330                         if (!(sl->mode & SL_MODE_CSLIP)) {
331                                 printk(KERN_WARNING "%s: compressed packet ignored\n", sl->dev->name);
332                                 return;
333                         }
334                         /* make sure we've reserved enough space for uncompress
335                            to use */
336                         if (count + 80 > sl->buffsize) {
337                                 sl->rx_over_errors++;
338                                 return;
339                         }
340                         count = slhc_uncompress(sl->slcomp, sl->rbuff, count);
341                         if (count <= 0)
342                                 return;
343                 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {
344                         if (!(sl->mode & SL_MODE_CSLIP)) {
345                                 /* turn on header compression */
346                                 sl->mode |= SL_MODE_CSLIP;
347                                 sl->mode &= ~SL_MODE_ADAPTIVE;
348                                 printk(KERN_INFO "%s: header compression turned on\n", sl->dev->name);
349                         }
350                         sl->rbuff[0] &= 0x4f;
351                         if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0)
352                                 return;
353                 }
354         }
355 #endif  /* SL_INCLUDE_CSLIP */
356
357         sl->rx_bytes += count;
358
359         skb = dev_alloc_skb(count);
360         if (skb == NULL) {
361                 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", sl->dev->name);
362                 sl->rx_dropped++;
363                 return;
364         }
365         skb->dev = sl->dev;
366         memcpy(skb_put(skb, count), sl->rbuff, count);
367         skb_reset_mac_header(skb);
368         skb->protocol = htons(ETH_P_IP);
369         netif_rx(skb);
370         sl->rx_packets++;
371 }
372
373 /* Encapsulate one IP datagram and stuff into a TTY queue. */
374 static void sl_encaps(struct slip *sl, unsigned char *icp, int len)
375 {
376         unsigned char *p;
377         int actual, count;
378
379         if (len > sl->mtu) {            /* Sigh, shouldn't occur BUT ... */
380                 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name);
381                 sl->tx_dropped++;
382                 sl_unlock(sl);
383                 return;
384         }
385
386         p = icp;
387 #ifdef SL_INCLUDE_CSLIP
388         if (sl->mode & SL_MODE_CSLIP)
389                 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);
390 #endif
391 #ifdef CONFIG_SLIP_MODE_SLIP6
392         if (sl->mode & SL_MODE_SLIP6)
393                 count = slip_esc6(p, (unsigned char *) sl->xbuff, len);
394         else
395 #endif
396                 count = slip_esc(p, (unsigned char *) sl->xbuff, len);
397
398         /* Order of next two lines is *very* important.
399          * When we are sending a little amount of data,
400          * the transfer may be completed inside the ops->write()
401          * routine, because it's running with interrupts enabled.
402          * In this case we *never* got WRITE_WAKEUP event,
403          * if we did not request it before write operation.
404          *       14 Oct 1994  Dmitry Gorodchanin.
405          */
406         set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
407         actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
408 #ifdef SL_CHECK_TRANSMIT
409         sl->dev->trans_start = jiffies;
410 #endif
411         sl->xleft = count - actual;
412         sl->xhead = sl->xbuff + actual;
413 #ifdef CONFIG_SLIP_SMART
414         /* VSV */
415         clear_bit(SLF_OUTWAIT, &sl->flags);     /* reset outfill flag */
416 #endif
417 }
418
419 /*
420  * Called by the driver when there's room for more data.  If we have
421  * more packets to send, we send them here.
422  */
423 static void slip_write_wakeup(struct tty_struct *tty)
424 {
425         int actual;
426         struct slip *sl = tty->disc_data;
427
428         /* First make sure we're connected. */
429         if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
430                 return;
431
432         if (sl->xleft <= 0)  {
433                 /* Now serial buffer is almost free & we can start
434                  * transmission of another packet */
435                 sl->tx_packets++;
436                 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
437                 sl_unlock(sl);
438                 return;
439         }
440
441         actual = tty->ops->write(tty, sl->xhead, sl->xleft);
442         sl->xleft -= actual;
443         sl->xhead += actual;
444 }
445
446 static void sl_tx_timeout(struct net_device *dev)
447 {
448         struct slip *sl = netdev_priv(dev);
449
450         spin_lock(&sl->lock);
451
452         if (netif_queue_stopped(dev)) {
453                 if (!netif_running(dev))
454                         goto out;
455
456                 /* May be we must check transmitter timeout here ?
457                  *      14 Oct 1994 Dmitry Gorodchanin.
458                  */
459 #ifdef SL_CHECK_TRANSMIT
460                 if (time_before(jiffies, dev->trans_start + 20 * HZ))  {
461                         /* 20 sec timeout not reached */
462                         goto out;
463                 }
464                 printk(KERN_WARNING "%s: transmit timed out, %s?\n",
465                         dev->name,
466                         (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
467                                 "bad line quality" : "driver error");
468                 sl->xleft = 0;
469                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
470                 sl_unlock(sl);
471 #endif
472         }
473 out:
474         spin_unlock(&sl->lock);
475 }
476
477
478 /* Encapsulate an IP datagram and kick it into a TTY queue. */
479 static netdev_tx_t
480 sl_xmit(struct sk_buff *skb, struct net_device *dev)
481 {
482         struct slip *sl = netdev_priv(dev);
483
484         spin_lock(&sl->lock);
485         if (!netif_running(dev)) {
486                 spin_unlock(&sl->lock);
487                 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
488                 dev_kfree_skb(skb);
489                 return NETDEV_TX_OK;
490         }
491         if (sl->tty == NULL) {
492                 spin_unlock(&sl->lock);
493                 dev_kfree_skb(skb);
494                 return NETDEV_TX_OK;
495         }
496
497         sl_lock(sl);
498         sl->tx_bytes += skb->len;
499         sl_encaps(sl, skb->data, skb->len);
500         spin_unlock(&sl->lock);
501
502         dev_kfree_skb(skb);
503         return NETDEV_TX_OK;
504 }
505
506
507 /******************************************
508  *   Routines looking at netdevice side.
509  ******************************************/
510
511 /* Netdevice UP -> DOWN routine */
512
513 static int
514 sl_close(struct net_device *dev)
515 {
516         struct slip *sl = netdev_priv(dev);
517
518         spin_lock_bh(&sl->lock);
519         if (sl->tty)
520                 /* TTY discipline is running. */
521                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
522         netif_stop_queue(dev);
523         sl->rcount   = 0;
524         sl->xleft    = 0;
525         spin_unlock_bh(&sl->lock);
526
527         return 0;
528 }
529
530 /* Netdevice DOWN -> UP routine */
531
532 static int sl_open(struct net_device *dev)
533 {
534         struct slip *sl = netdev_priv(dev);
535
536         if (sl->tty == NULL)
537                 return -ENODEV;
538
539         sl->flags &= (1 << SLF_INUSE);
540         netif_start_queue(dev);
541         return 0;
542 }
543
544 /* Netdevice change MTU request */
545
546 static int sl_change_mtu(struct net_device *dev, int new_mtu)
547 {
548         struct slip *sl = netdev_priv(dev);
549
550         if (new_mtu < 68 || new_mtu > 65534)
551                 return -EINVAL;
552
553         if (new_mtu != dev->mtu)
554                 return sl_realloc_bufs(sl, new_mtu);
555         return 0;
556 }
557
558 /* Netdevice get statistics request */
559
560 static struct net_device_stats *
561 sl_get_stats(struct net_device *dev)
562 {
563         static struct net_device_stats stats;
564         struct slip *sl = netdev_priv(dev);
565 #ifdef SL_INCLUDE_CSLIP
566         struct slcompress *comp;
567 #endif
568
569         memset(&stats, 0, sizeof(struct net_device_stats));
570
571         stats.rx_packets     = sl->rx_packets;
572         stats.tx_packets     = sl->tx_packets;
573         stats.rx_bytes       = sl->rx_bytes;
574         stats.tx_bytes       = sl->tx_bytes;
575         stats.rx_dropped     = sl->rx_dropped;
576         stats.tx_dropped     = sl->tx_dropped;
577         stats.tx_errors      = sl->tx_errors;
578         stats.rx_errors      = sl->rx_errors;
579         stats.rx_over_errors = sl->rx_over_errors;
580 #ifdef SL_INCLUDE_CSLIP
581         stats.rx_fifo_errors = sl->rx_compressed;
582         stats.tx_fifo_errors = sl->tx_compressed;
583         stats.collisions     = sl->tx_misses;
584         comp = sl->slcomp;
585         if (comp) {
586                 stats.rx_fifo_errors += comp->sls_i_compressed;
587                 stats.rx_dropped     += comp->sls_i_tossed;
588                 stats.tx_fifo_errors += comp->sls_o_compressed;
589                 stats.collisions     += comp->sls_o_misses;
590         }
591 #endif /* CONFIG_INET */
592         return (&stats);
593 }
594
595 /* Netdevice register callback */
596
597 static int sl_init(struct net_device *dev)
598 {
599         struct slip *sl = netdev_priv(dev);
600
601         /*
602          *      Finish setting up the DEVICE info.
603          */
604
605         dev->mtu                = sl->mtu;
606         dev->type               = ARPHRD_SLIP + sl->mode;
607 #ifdef SL_CHECK_TRANSMIT
608         dev->watchdog_timeo     = 20*HZ;
609 #endif
610         return 0;
611 }
612
613
614 static void sl_uninit(struct net_device *dev)
615 {
616         struct slip *sl = netdev_priv(dev);
617
618         sl_free_bufs(sl);
619 }
620
621 /* Hook the destructor so we can free slip devices at the right point in time */
622 static void sl_free_netdev(struct net_device *dev)
623 {
624         int i = dev->base_addr;
625         free_netdev(dev);
626         slip_devs[i] = NULL;
627 }
628
629 static const struct net_device_ops sl_netdev_ops = {
630         .ndo_init               = sl_init,
631         .ndo_uninit             = sl_uninit,
632         .ndo_open               = sl_open,
633         .ndo_stop               = sl_close,
634         .ndo_start_xmit         = sl_xmit,
635         .ndo_get_stats          = sl_get_stats,
636         .ndo_change_mtu         = sl_change_mtu,
637         .ndo_tx_timeout         = sl_tx_timeout,
638 #ifdef CONFIG_SLIP_SMART
639         .ndo_do_ioctl           = sl_ioctl,
640 #endif
641 };
642
643
644 static void sl_setup(struct net_device *dev)
645 {
646         dev->netdev_ops         = &sl_netdev_ops;
647         dev->destructor         = sl_free_netdev;
648
649         dev->hard_header_len    = 0;
650         dev->addr_len           = 0;
651         dev->tx_queue_len       = 10;
652
653         /* New-style flags. */
654         dev->flags              = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
655 }
656
657 /******************************************
658   Routines looking at TTY side.
659  ******************************************/
660
661
662 /*
663  * Handle the 'receiver data ready' interrupt.
664  * This function is called by the 'tty_io' module in the kernel when
665  * a block of SLIP data has been received, which can now be decapsulated
666  * and sent on to some IP layer for further processing. This will not
667  * be re-entered while running but other ldisc functions may be called
668  * in parallel
669  */
670
671 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
672                                                         char *fp, int count)
673 {
674         struct slip *sl = tty->disc_data;
675
676         if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
677                 return;
678
679         /* Read the characters out of the buffer */
680         while (count--) {
681                 if (fp && *fp++) {
682                         if (!test_and_set_bit(SLF_ERROR, &sl->flags))
683                                 sl->rx_errors++;
684                         cp++;
685                         continue;
686                 }
687 #ifdef CONFIG_SLIP_MODE_SLIP6
688                 if (sl->mode & SL_MODE_SLIP6)
689                         slip_unesc6(sl, *cp++);
690                 else
691 #endif
692                         slip_unesc(sl, *cp++);
693         }
694 }
695
696 /************************************
697  *  slip_open helper routines.
698  ************************************/
699
700 /* Collect hanged up channels */
701 static void sl_sync(void)
702 {
703         int i;
704         struct net_device *dev;
705         struct slip       *sl;
706
707         for (i = 0; i < slip_maxdev; i++) {
708                 dev = slip_devs[i];
709                 if (dev == NULL)
710                         break;
711
712                 sl = netdev_priv(dev);
713                 if (sl->tty || sl->leased)
714                         continue;
715                 if (dev->flags & IFF_UP)
716                         dev_close(dev);
717         }
718 }
719
720
721 /* Find a free SLIP channel, and link in this `tty' line. */
722 static struct slip *sl_alloc(dev_t line)
723 {
724         int i;
725         struct net_device *dev = NULL;
726         struct slip       *sl;
727
728         if (slip_devs == NULL)
729                 return NULL;    /* Master array missing ! */
730
731         for (i = 0; i < slip_maxdev; i++) {
732                 dev = slip_devs[i];
733                 if (dev == NULL)
734                         break;
735         }
736         /* Sorry, too many, all slots in use */
737         if (i >= slip_maxdev)
738                 return NULL;
739
740         if (dev) {
741                 sl = netdev_priv(dev);
742                 if (test_bit(SLF_INUSE, &sl->flags)) {
743                         unregister_netdevice(dev);
744                         dev = NULL;
745                         slip_devs[i] = NULL;
746                 }
747         }
748
749         if (!dev) {
750                 char name[IFNAMSIZ];
751                 sprintf(name, "sl%d", i);
752
753                 dev = alloc_netdev(sizeof(*sl), name, sl_setup);
754                 if (!dev)
755                         return NULL;
756                 dev->base_addr  = i;
757         }
758
759         sl = netdev_priv(dev);
760
761         /* Initialize channel control data */
762         sl->magic       = SLIP_MAGIC;
763         sl->dev         = dev;
764         spin_lock_init(&sl->lock);
765         sl->mode        = SL_MODE_DEFAULT;
766 #ifdef CONFIG_SLIP_SMART
767         /* initialize timer_list struct */
768         init_timer(&sl->keepalive_timer);
769         sl->keepalive_timer.data = (unsigned long)sl;
770         sl->keepalive_timer.function = sl_keepalive;
771         init_timer(&sl->outfill_timer);
772         sl->outfill_timer.data = (unsigned long)sl;
773         sl->outfill_timer.function = sl_outfill;
774 #endif
775         slip_devs[i] = dev;
776         return sl;
777 }
778
779 /*
780  * Open the high-level part of the SLIP channel.
781  * This function is called by the TTY module when the
782  * SLIP line discipline is called for.  Because we are
783  * sure the tty line exists, we only have to link it to
784  * a free SLIP channel...
785  *
786  * Called in process context serialized from other ldisc calls.
787  */
788
789 static int slip_open(struct tty_struct *tty)
790 {
791         struct slip *sl;
792         int err;
793
794         if (!capable(CAP_NET_ADMIN))
795                 return -EPERM;
796
797         if (tty->ops->write == NULL)
798                 return -EOPNOTSUPP;
799
800         /* RTnetlink lock is misused here to serialize concurrent
801            opens of slip channels. There are better ways, but it is
802            the simplest one.
803          */
804         rtnl_lock();
805
806         /* Collect hanged up channels. */
807         sl_sync();
808
809         sl = tty->disc_data;
810
811         err = -EEXIST;
812         /* First make sure we're not already connected. */
813         if (sl && sl->magic == SLIP_MAGIC)
814                 goto err_exit;
815
816         /* OK.  Find a free SLIP channel to use. */
817         err = -ENFILE;
818         sl = sl_alloc(tty_devnum(tty));
819         if (sl == NULL)
820                 goto err_exit;
821
822         sl->tty = tty;
823         tty->disc_data = sl;
824         sl->line = tty_devnum(tty);
825         sl->pid = current->pid;
826
827         if (!test_bit(SLF_INUSE, &sl->flags)) {
828                 /* Perform the low-level SLIP initialization. */
829                 err = sl_alloc_bufs(sl, SL_MTU);
830                 if (err)
831                         goto err_free_chan;
832
833                 set_bit(SLF_INUSE, &sl->flags);
834
835                 err = register_netdevice(sl->dev);
836                 if (err)
837                         goto err_free_bufs;
838         }
839
840 #ifdef CONFIG_SLIP_SMART
841         if (sl->keepalive) {
842                 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;
843                 add_timer(&sl->keepalive_timer);
844         }
845         if (sl->outfill) {
846                 sl->outfill_timer.expires = jiffies + sl->outfill * HZ;
847                 add_timer(&sl->outfill_timer);
848         }
849 #endif
850
851         /* Done.  We have linked the TTY line to a channel. */
852         rtnl_unlock();
853         tty->receive_room = 65536;      /* We don't flow control */
854         return sl->dev->base_addr;
855
856 err_free_bufs:
857         sl_free_bufs(sl);
858
859 err_free_chan:
860         sl->tty = NULL;
861         tty->disc_data = NULL;
862         clear_bit(SLF_INUSE, &sl->flags);
863
864 err_exit:
865         rtnl_unlock();
866
867         /* Count references from TTY module */
868         return err;
869 }
870
871 /*
872  * Close down a SLIP channel.
873  * This means flushing out any pending queues, and then returning. This
874  * call is serialized against other ldisc functions.
875  *
876  * We also use this method fo a hangup event
877  */
878
879 static void slip_close(struct tty_struct *tty)
880 {
881         struct slip *sl = tty->disc_data;
882
883         /* First make sure we're connected. */
884         if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
885                 return;
886
887         tty->disc_data = NULL;
888         sl->tty = NULL;
889         if (!sl->leased)
890                 sl->line = 0;
891
892         /* VSV = very important to remove timers */
893 #ifdef CONFIG_SLIP_SMART
894         del_timer_sync(&sl->keepalive_timer);
895         del_timer_sync(&sl->outfill_timer);
896 #endif
897         /* Flush network side */
898         unregister_netdev(sl->dev);
899         /* This will complete via sl_free_netdev */
900 }
901
902 static int slip_hangup(struct tty_struct *tty)
903 {
904         slip_close(tty);
905         return 0;
906 }
907  /************************************************************************
908   *                     STANDARD SLIP ENCAPSULATION                      *
909   ************************************************************************/
910
911 static int slip_esc(unsigned char *s, unsigned char *d, int len)
912 {
913         unsigned char *ptr = d;
914         unsigned char c;
915
916         /*
917          * Send an initial END character to flush out any
918          * data that may have accumulated in the receiver
919          * due to line noise.
920          */
921
922         *ptr++ = END;
923
924         /*
925          * For each byte in the packet, send the appropriate
926          * character sequence, according to the SLIP protocol.
927          */
928
929         while (len-- > 0) {
930                 switch (c = *s++) {
931                 case END:
932                         *ptr++ = ESC;
933                         *ptr++ = ESC_END;
934                         break;
935                 case ESC:
936                         *ptr++ = ESC;
937                         *ptr++ = ESC_ESC;
938                         break;
939                 default:
940                         *ptr++ = c;
941                         break;
942                 }
943         }
944         *ptr++ = END;
945         return (ptr - d);
946 }
947
948 static void slip_unesc(struct slip *sl, unsigned char s)
949 {
950
951         switch (s) {
952         case END:
953 #ifdef CONFIG_SLIP_SMART
954                 /* drop keeptest bit = VSV */
955                 if (test_bit(SLF_KEEPTEST, &sl->flags))
956                         clear_bit(SLF_KEEPTEST, &sl->flags);
957 #endif
958
959                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
960                     (sl->rcount > 2))
961                         sl_bump(sl);
962                 clear_bit(SLF_ESCAPE, &sl->flags);
963                 sl->rcount = 0;
964                 return;
965
966         case ESC:
967                 set_bit(SLF_ESCAPE, &sl->flags);
968                 return;
969         case ESC_ESC:
970                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
971                         s = ESC;
972                 break;
973         case ESC_END:
974                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
975                         s = END;
976                 break;
977         }
978         if (!test_bit(SLF_ERROR, &sl->flags))  {
979                 if (sl->rcount < sl->buffsize)  {
980                         sl->rbuff[sl->rcount++] = s;
981                         return;
982                 }
983                 sl->rx_over_errors++;
984                 set_bit(SLF_ERROR, &sl->flags);
985         }
986 }
987
988
989 #ifdef CONFIG_SLIP_MODE_SLIP6
990 /************************************************************************
991  *                       6 BIT SLIP ENCAPSULATION                       *
992  ************************************************************************/
993
994 static int slip_esc6(unsigned char *s, unsigned char *d, int len)
995 {
996         unsigned char *ptr = d;
997         unsigned char c;
998         int i;
999         unsigned short v = 0;
1000         short bits = 0;
1001
1002         /*
1003          * Send an initial END character to flush out any
1004          * data that may have accumulated in the receiver
1005          * due to line noise.
1006          */
1007
1008         *ptr++ = 0x70;
1009
1010         /*
1011          * Encode the packet into printable ascii characters
1012          */
1013
1014         for (i = 0; i < len; ++i) {
1015                 v = (v << 8) | s[i];
1016                 bits += 8;
1017                 while (bits >= 6) {
1018                         bits -= 6;
1019                         c = 0x30 + ((v >> bits) & 0x3F);
1020                         *ptr++ = c;
1021                 }
1022         }
1023         if (bits) {
1024                 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1025                 *ptr++ = c;
1026         }
1027         *ptr++ = 0x70;
1028         return ptr - d;
1029 }
1030
1031 static void slip_unesc6(struct slip *sl, unsigned char s)
1032 {
1033         unsigned char c;
1034
1035         if (s == 0x70) {
1036 #ifdef CONFIG_SLIP_SMART
1037                 /* drop keeptest bit = VSV */
1038                 if (test_bit(SLF_KEEPTEST, &sl->flags))
1039                         clear_bit(SLF_KEEPTEST, &sl->flags);
1040 #endif
1041
1042                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
1043                     (sl->rcount > 2))
1044                         sl_bump(sl);
1045                 sl->rcount = 0;
1046                 sl->xbits = 0;
1047                 sl->xdata = 0;
1048         } else if (s >= 0x30 && s < 0x70) {
1049                 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1050                 sl->xbits += 6;
1051                 if (sl->xbits >= 8) {
1052                         sl->xbits -= 8;
1053                         c = (unsigned char)(sl->xdata >> sl->xbits);
1054                         if (!test_bit(SLF_ERROR, &sl->flags))  {
1055                                 if (sl->rcount < sl->buffsize)  {
1056                                         sl->rbuff[sl->rcount++] = c;
1057                                         return;
1058                                 }
1059                                 sl->rx_over_errors++;
1060                                 set_bit(SLF_ERROR, &sl->flags);
1061                         }
1062                 }
1063         }
1064 }
1065 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1066
1067 /* Perform I/O control on an active SLIP channel. */
1068 static int slip_ioctl(struct tty_struct *tty, struct file *file,
1069                                         unsigned int cmd, unsigned long arg)
1070 {
1071         struct slip *sl = tty->disc_data;
1072         unsigned int tmp;
1073         int __user *p = (int __user *)arg;
1074
1075         /* First make sure we're connected. */
1076         if (!sl || sl->magic != SLIP_MAGIC)
1077                 return -EINVAL;
1078
1079         switch (cmd) {
1080         case SIOCGIFNAME:
1081                 tmp = strlen(sl->dev->name) + 1;
1082                 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1083                         return -EFAULT;
1084                 return 0;
1085
1086         case SIOCGIFENCAP:
1087                 if (put_user(sl->mode, p))
1088                         return -EFAULT;
1089                 return 0;
1090
1091         case SIOCSIFENCAP:
1092                 if (get_user(tmp, p))
1093                         return -EFAULT;
1094 #ifndef SL_INCLUDE_CSLIP
1095                 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
1096                         return -EINVAL;
1097 #else
1098                 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1099                     (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
1100                         /* return -EINVAL; */
1101                         tmp &= ~SL_MODE_ADAPTIVE;
1102 #endif
1103 #ifndef CONFIG_SLIP_MODE_SLIP6
1104                 if (tmp & SL_MODE_SLIP6)
1105                         return -EINVAL;
1106 #endif
1107                 sl->mode = tmp;
1108                 sl->dev->type = ARPHRD_SLIP + sl->mode;
1109                 return 0;
1110
1111         case SIOCSIFHWADDR:
1112                 return -EINVAL;
1113
1114 #ifdef CONFIG_SLIP_SMART
1115         /* VSV changes start here */
1116         case SIOCSKEEPALIVE:
1117                 if (get_user(tmp, p))
1118                         return -EFAULT;
1119                 if (tmp > 255) /* max for unchar */
1120                         return -EINVAL;
1121
1122                 spin_lock_bh(&sl->lock);
1123                 if (!sl->tty) {
1124                         spin_unlock_bh(&sl->lock);
1125                         return -ENODEV;
1126                 }
1127                 sl->keepalive = (u8)tmp;
1128                 if (sl->keepalive != 0) {
1129                         mod_timer(&sl->keepalive_timer,
1130                                         jiffies + sl->keepalive * HZ);
1131                         set_bit(SLF_KEEPTEST, &sl->flags);
1132                 } else
1133                         del_timer(&sl->keepalive_timer);
1134                 spin_unlock_bh(&sl->lock);
1135                 return 0;
1136
1137         case SIOCGKEEPALIVE:
1138                 if (put_user(sl->keepalive, p))
1139                         return -EFAULT;
1140                 return 0;
1141
1142         case SIOCSOUTFILL:
1143                 if (get_user(tmp, p))
1144                         return -EFAULT;
1145                 if (tmp > 255) /* max for unchar */
1146                         return -EINVAL;
1147                 spin_lock_bh(&sl->lock);
1148                 if (!sl->tty) {
1149                         spin_unlock_bh(&sl->lock);
1150                         return -ENODEV;
1151                 }
1152                 sl->outfill = (u8)tmp;
1153                 if (sl->outfill != 0) {
1154                         mod_timer(&sl->outfill_timer,
1155                                                 jiffies + sl->outfill * HZ);
1156                         set_bit(SLF_OUTWAIT, &sl->flags);
1157                 } else
1158                         del_timer(&sl->outfill_timer);
1159                 spin_unlock_bh(&sl->lock);
1160                 return 0;
1161
1162         case SIOCGOUTFILL:
1163                 if (put_user(sl->outfill, p))
1164                         return -EFAULT;
1165                 return 0;
1166         /* VSV changes end */
1167 #endif
1168         default:
1169                 return tty_mode_ioctl(tty, file, cmd, arg);
1170         }
1171 }
1172
1173 #ifdef CONFIG_COMPAT
1174 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
1175                                         unsigned int cmd, unsigned long arg)
1176 {
1177         switch (cmd) {
1178         case SIOCGIFNAME:
1179         case SIOCGIFENCAP:
1180         case SIOCSIFENCAP:
1181         case SIOCSIFHWADDR:
1182         case SIOCSKEEPALIVE:
1183         case SIOCGKEEPALIVE:
1184         case SIOCSOUTFILL:
1185         case SIOCGOUTFILL:
1186                 return slip_ioctl(tty, file, cmd,
1187                                   (unsigned long)compat_ptr(arg));
1188         }
1189
1190         return -ENOIOCTLCMD;
1191 }
1192 #endif
1193
1194 /* VSV changes start here */
1195 #ifdef CONFIG_SLIP_SMART
1196 /* function do_ioctl called from net/core/dev.c
1197    to allow get/set outfill/keepalive parameter
1198    by ifconfig                                 */
1199
1200 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
1201 {
1202         struct slip *sl = netdev_priv(dev);
1203         unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1204
1205         if (sl == NULL)         /* Allocation failed ?? */
1206                 return -ENODEV;
1207
1208         spin_lock_bh(&sl->lock);
1209
1210         if (!sl->tty) {
1211                 spin_unlock_bh(&sl->lock);
1212                 return -ENODEV;
1213         }
1214
1215         switch (cmd) {
1216         case SIOCSKEEPALIVE:
1217                 /* max for unchar */
1218                 if ((unsigned)*p > 255) {
1219                         spin_unlock_bh(&sl->lock);
1220                         return -EINVAL;
1221                 }
1222                 sl->keepalive = (u8)*p;
1223                 if (sl->keepalive != 0) {
1224                         sl->keepalive_timer.expires =
1225                                                 jiffies + sl->keepalive * HZ;
1226                         mod_timer(&sl->keepalive_timer,
1227                                                 jiffies + sl->keepalive * HZ);
1228                         set_bit(SLF_KEEPTEST, &sl->flags);
1229                 } else
1230                         del_timer(&sl->keepalive_timer);
1231                 break;
1232
1233         case SIOCGKEEPALIVE:
1234                 *p = sl->keepalive;
1235                 break;
1236
1237         case SIOCSOUTFILL:
1238                 if ((unsigned)*p > 255) { /* max for unchar */
1239                         spin_unlock_bh(&sl->lock);
1240                         return -EINVAL;
1241                 }
1242                 sl->outfill = (u8)*p;
1243                 if (sl->outfill != 0) {
1244                         mod_timer(&sl->outfill_timer,
1245                                                 jiffies + sl->outfill * HZ);
1246                         set_bit(SLF_OUTWAIT, &sl->flags);
1247                 } else
1248                         del_timer(&sl->outfill_timer);
1249                 break;
1250
1251         case SIOCGOUTFILL:
1252                 *p = sl->outfill;
1253                 break;
1254
1255         case SIOCSLEASE:
1256                 /* Resolve race condition, when ioctl'ing hanged up
1257                    and opened by another process device.
1258                  */
1259                 if (sl->tty != current->signal->tty &&
1260                                                 sl->pid != current->pid) {
1261                         spin_unlock_bh(&sl->lock);
1262                         return -EPERM;
1263                 }
1264                 sl->leased = 0;
1265                 if (*p)
1266                         sl->leased = 1;
1267                 break;
1268
1269         case SIOCGLEASE:
1270                 *p = sl->leased;
1271         };
1272         spin_unlock_bh(&sl->lock);
1273         return 0;
1274 }
1275 #endif
1276 /* VSV changes end */
1277
1278 static struct tty_ldisc_ops sl_ldisc = {
1279         .owner          = THIS_MODULE,
1280         .magic          = TTY_LDISC_MAGIC,
1281         .name           = "slip",
1282         .open           = slip_open,
1283         .close          = slip_close,
1284         .hangup         = slip_hangup,
1285         .ioctl          = slip_ioctl,
1286 #ifdef CONFIG_COMPAT
1287         .compat_ioctl   = slip_compat_ioctl,
1288 #endif
1289         .receive_buf    = slip_receive_buf,
1290         .write_wakeup   = slip_write_wakeup,
1291 };
1292
1293 static int __init slip_init(void)
1294 {
1295         int status;
1296
1297         if (slip_maxdev < 4)
1298                 slip_maxdev = 4; /* Sanity */
1299
1300         printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1301 #ifdef CONFIG_SLIP_MODE_SLIP6
1302                " (6 bit encapsulation enabled)"
1303 #endif
1304                ".\n",
1305                SLIP_VERSION, slip_maxdev);
1306 #if defined(SL_INCLUDE_CSLIP)
1307         printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1308 #endif
1309 #ifdef CONFIG_SLIP_SMART
1310         printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1311 #endif
1312
1313         slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev,
1314                                                                 GFP_KERNEL);
1315         if (!slip_devs) {
1316                 printk(KERN_ERR "SLIP: Can't allocate slip devices array.\n");
1317                 return -ENOMEM;
1318         }
1319
1320         /* Fill in our line protocol discipline, and register it */
1321         status = tty_register_ldisc(N_SLIP, &sl_ldisc);
1322         if (status != 0) {
1323                 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1324                 kfree(slip_devs);
1325         }
1326         return status;
1327 }
1328
1329 static void __exit slip_exit(void)
1330 {
1331         int i;
1332         struct net_device *dev;
1333         struct slip *sl;
1334         unsigned long timeout = jiffies + HZ;
1335         int busy = 0;
1336
1337         if (slip_devs == NULL)
1338                 return;
1339
1340         /* First of all: check for active disciplines and hangup them.
1341          */
1342         do {
1343                 if (busy)
1344                         msleep_interruptible(100);
1345
1346                 busy = 0;
1347                 for (i = 0; i < slip_maxdev; i++) {
1348                         dev = slip_devs[i];
1349                         if (!dev)
1350                                 continue;
1351                         sl = netdev_priv(dev);
1352                         spin_lock_bh(&sl->lock);
1353                         if (sl->tty) {
1354                                 busy++;
1355                                 tty_hangup(sl->tty);
1356                         }
1357                         spin_unlock_bh(&sl->lock);
1358                 }
1359         } while (busy && time_before(jiffies, timeout));
1360
1361         /* FIXME: hangup is async so we should wait when doing this second
1362            phase */
1363
1364         for (i = 0; i < slip_maxdev; i++) {
1365                 dev = slip_devs[i];
1366                 if (!dev)
1367                         continue;
1368                 slip_devs[i] = NULL;
1369
1370                 sl = netdev_priv(dev);
1371                 if (sl->tty) {
1372                         printk(KERN_ERR "%s: tty discipline still running\n",
1373                                dev->name);
1374                         /* Intentionally leak the control block. */
1375                         dev->destructor = NULL;
1376                 }
1377
1378                 unregister_netdev(dev);
1379         }
1380
1381         kfree(slip_devs);
1382         slip_devs = NULL;
1383
1384         i = tty_unregister_ldisc(N_SLIP);
1385         if (i != 0)
1386                 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1387 }
1388
1389 module_init(slip_init);
1390 module_exit(slip_exit);
1391
1392 #ifdef CONFIG_SLIP_SMART
1393 /*
1394  * This is start of the code for multislip style line checking
1395  * added by Stanislav Voronyi. All changes before marked VSV
1396  */
1397
1398 static void sl_outfill(unsigned long sls)
1399 {
1400         struct slip *sl = (struct slip *)sls;
1401
1402         spin_lock(&sl->lock);
1403
1404         if (sl->tty == NULL)
1405                 goto out;
1406
1407         if (sl->outfill) {
1408                 if (test_bit(SLF_OUTWAIT, &sl->flags)) {
1409                         /* no packets were transmitted, do outfill */
1410 #ifdef CONFIG_SLIP_MODE_SLIP6
1411                         unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1412 #else
1413                         unsigned char s = END;
1414 #endif
1415                         /* put END into tty queue. Is it right ??? */
1416                         if (!netif_queue_stopped(sl->dev)) {
1417                                 /* if device busy no outfill */
1418                                 sl->tty->ops->write(sl->tty, &s, 1);
1419                         }
1420                 } else
1421                         set_bit(SLF_OUTWAIT, &sl->flags);
1422
1423                 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1424         }
1425 out:
1426         spin_unlock(&sl->lock);
1427 }
1428
1429 static void sl_keepalive(unsigned long sls)
1430 {
1431         struct slip *sl = (struct slip *)sls;
1432
1433         spin_lock(&sl->lock);
1434
1435         if (sl->tty == NULL)
1436                 goto out;
1437
1438         if (sl->keepalive) {
1439                 if (test_bit(SLF_KEEPTEST, &sl->flags)) {
1440                         /* keepalive still high :(, we must hangup */
1441                         if (sl->outfill)
1442                                 /* outfill timer must be deleted too */
1443                                 (void)del_timer(&sl->outfill_timer);
1444                         printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1445                         /* this must hangup tty & close slip */
1446                         tty_hangup(sl->tty);
1447                         /* I think we need not something else */
1448                         goto out;
1449                 } else
1450                         set_bit(SLF_KEEPTEST, &sl->flags);
1451
1452                 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1453         }
1454 out:
1455         spin_unlock(&sl->lock);
1456 }
1457
1458 #endif
1459 MODULE_LICENSE("GPL");
1460 MODULE_ALIAS_LDISC(N_SLIP);