ppp, slip: Validate VJ compression slot parameters completely
[linux-3.10.git] / drivers / net / slip / 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/uaccess.h>
68 #include <linux/bitops.h>
69 #include <linux/sched.h>
70 #include <linux/string.h>
71 #include <linux/mm.h>
72 #include <linux/interrupt.h>
73 #include <linux/in.h>
74 #include <linux/tty.h>
75 #include <linux/errno.h>
76 #include <linux/netdevice.h>
77 #include <linux/etherdevice.h>
78 #include <linux/skbuff.h>
79 #include <linux/rtnetlink.h>
80 #include <linux/if_arp.h>
81 #include <linux/if_slip.h>
82 #include <linux/compat.h>
83 #include <linux/delay.h>
84 #include <linux/init.h>
85 #include <linux/slab.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 (IS_ERR(slcomp))
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 #endif
185 #ifdef CONFIG_SLIP_MODE_SLIP6
186         sl->xdata    = 0;
187         sl->xbits    = 0;
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         slhc_free(slcomp);
197 #endif
198         kfree(xbuff);
199         kfree(rbuff);
200         return err;
201 }
202
203 /* Free a SLIP channel buffers. */
204 static void sl_free_bufs(struct slip *sl)
205 {
206         /* Free all SLIP frame buffers. */
207         kfree(xchg(&sl->rbuff, NULL));
208         kfree(xchg(&sl->xbuff, NULL));
209 #ifdef SL_INCLUDE_CSLIP
210         kfree(xchg(&sl->cbuff, NULL));
211         slhc_free(xchg(&sl->slcomp, NULL));
212 #endif
213 }
214
215 /*
216    Reallocate slip channel buffers.
217  */
218
219 static int sl_realloc_bufs(struct slip *sl, int mtu)
220 {
221         int err = 0;
222         struct net_device *dev = sl->dev;
223         unsigned char *xbuff, *rbuff;
224 #ifdef SL_INCLUDE_CSLIP
225         unsigned char *cbuff;
226 #endif
227         int len = mtu * 2;
228
229 /*
230  * allow for arrival of larger UDP packets, even if we say not to
231  * also fixes a bug in which SunOS sends 512-byte packets even with
232  * an MSS of 128
233  */
234         if (len < 576 * 2)
235                 len = 576 * 2;
236
237         xbuff = kmalloc(len + 4, GFP_ATOMIC);
238         rbuff = kmalloc(len + 4, GFP_ATOMIC);
239 #ifdef SL_INCLUDE_CSLIP
240         cbuff = kmalloc(len + 4, GFP_ATOMIC);
241 #endif
242
243
244 #ifdef SL_INCLUDE_CSLIP
245         if (xbuff == NULL || rbuff == NULL || cbuff == NULL)  {
246 #else
247         if (xbuff == NULL || rbuff == NULL)  {
248 #endif
249                 if (mtu > sl->mtu) {
250                         printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n",
251                                dev->name);
252                         err = -ENOBUFS;
253                 }
254                 goto done;
255         }
256         spin_lock_bh(&sl->lock);
257
258         err = -ENODEV;
259         if (sl->tty == NULL)
260                 goto done_on_bh;
261
262         xbuff    = xchg(&sl->xbuff, xbuff);
263         rbuff    = xchg(&sl->rbuff, rbuff);
264 #ifdef SL_INCLUDE_CSLIP
265         cbuff    = xchg(&sl->cbuff, cbuff);
266 #endif
267         if (sl->xleft)  {
268                 if (sl->xleft <= len)  {
269                         memcpy(sl->xbuff, sl->xhead, sl->xleft);
270                 } else  {
271                         sl->xleft = 0;
272                         dev->stats.tx_dropped++;
273                 }
274         }
275         sl->xhead = sl->xbuff;
276
277         if (sl->rcount)  {
278                 if (sl->rcount <= len) {
279                         memcpy(sl->rbuff, rbuff, sl->rcount);
280                 } else  {
281                         sl->rcount = 0;
282                         dev->stats.rx_over_errors++;
283                         set_bit(SLF_ERROR, &sl->flags);
284                 }
285         }
286         sl->mtu      = mtu;
287         dev->mtu      = mtu;
288         sl->buffsize = len;
289         err = 0;
290
291 done_on_bh:
292         spin_unlock_bh(&sl->lock);
293
294 done:
295         kfree(xbuff);
296         kfree(rbuff);
297 #ifdef SL_INCLUDE_CSLIP
298         kfree(cbuff);
299 #endif
300         return err;
301 }
302
303
304 /* Set the "sending" flag.  This must be atomic hence the set_bit. */
305 static inline void sl_lock(struct slip *sl)
306 {
307         netif_stop_queue(sl->dev);
308 }
309
310
311 /* Clear the "sending" flag.  This must be atomic, hence the ASM. */
312 static inline void sl_unlock(struct slip *sl)
313 {
314         netif_wake_queue(sl->dev);
315 }
316
317 /* Send one completely decapsulated IP datagram to the IP layer. */
318 static void sl_bump(struct slip *sl)
319 {
320         struct net_device *dev = sl->dev;
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", 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                                 dev->stats.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", 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         dev->stats.rx_bytes += count;
358
359         skb = dev_alloc_skb(count);
360         if (skb == NULL) {
361                 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name);
362                 dev->stats.rx_dropped++;
363                 return;
364         }
365         skb->dev = 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_ni(skb);
370         dev->stats.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->dev->stats.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, sl->xbuff, len);
394         else
395 #endif
396                 count = slip_esc(p, 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->dev->stats.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(dev) + 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         dev->stats.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 rtnl_link_stats64 *
561 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
562 {
563         struct net_device_stats *devstats = &dev->stats;
564 #ifdef SL_INCLUDE_CSLIP
565         struct slip *sl = netdev_priv(dev);
566         struct slcompress *comp = sl->slcomp;
567 #endif
568         stats->rx_packets     = devstats->rx_packets;
569         stats->tx_packets     = devstats->tx_packets;
570         stats->rx_bytes       = devstats->rx_bytes;
571         stats->tx_bytes       = devstats->tx_bytes;
572         stats->rx_dropped     = devstats->rx_dropped;
573         stats->tx_dropped     = devstats->tx_dropped;
574         stats->tx_errors      = devstats->tx_errors;
575         stats->rx_errors      = devstats->rx_errors;
576         stats->rx_over_errors = devstats->rx_over_errors;
577
578 #ifdef SL_INCLUDE_CSLIP
579         if (comp) {
580                 /* Generic compressed statistics */
581                 stats->rx_compressed   = comp->sls_i_compressed;
582                 stats->tx_compressed   = comp->sls_o_compressed;
583
584                 /* Are we really still needs this? */
585                 stats->rx_fifo_errors += comp->sls_i_compressed;
586                 stats->rx_dropped     += comp->sls_i_tossed;
587                 stats->tx_fifo_errors += comp->sls_o_compressed;
588                 stats->collisions     += comp->sls_o_misses;
589         }
590 #endif
591         return stats;
592 }
593
594 /* Netdevice register callback */
595
596 static int sl_init(struct net_device *dev)
597 {
598         struct slip *sl = netdev_priv(dev);
599
600         /*
601          *      Finish setting up the DEVICE info.
602          */
603
604         dev->mtu                = sl->mtu;
605         dev->type               = ARPHRD_SLIP + sl->mode;
606 #ifdef SL_CHECK_TRANSMIT
607         dev->watchdog_timeo     = 20*HZ;
608 #endif
609         return 0;
610 }
611
612
613 static void sl_uninit(struct net_device *dev)
614 {
615         struct slip *sl = netdev_priv(dev);
616
617         sl_free_bufs(sl);
618 }
619
620 /* Hook the destructor so we can free slip devices at the right point in time */
621 static void sl_free_netdev(struct net_device *dev)
622 {
623         int i = dev->base_addr;
624         free_netdev(dev);
625         slip_devs[i] = NULL;
626 }
627
628 static const struct net_device_ops sl_netdev_ops = {
629         .ndo_init               = sl_init,
630         .ndo_uninit             = sl_uninit,
631         .ndo_open               = sl_open,
632         .ndo_stop               = sl_close,
633         .ndo_start_xmit         = sl_xmit,
634         .ndo_get_stats64        = sl_get_stats64,
635         .ndo_change_mtu         = sl_change_mtu,
636         .ndo_tx_timeout         = sl_tx_timeout,
637 #ifdef CONFIG_SLIP_SMART
638         .ndo_do_ioctl           = sl_ioctl,
639 #endif
640 };
641
642
643 static void sl_setup(struct net_device *dev)
644 {
645         dev->netdev_ops         = &sl_netdev_ops;
646         dev->destructor         = sl_free_netdev;
647
648         dev->hard_header_len    = 0;
649         dev->addr_len           = 0;
650         dev->tx_queue_len       = 10;
651
652         /* New-style flags. */
653         dev->flags              = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
654 }
655
656 /******************************************
657   Routines looking at TTY side.
658  ******************************************/
659
660
661 /*
662  * Handle the 'receiver data ready' interrupt.
663  * This function is called by the 'tty_io' module in the kernel when
664  * a block of SLIP data has been received, which can now be decapsulated
665  * and sent on to some IP layer for further processing. This will not
666  * be re-entered while running but other ldisc functions may be called
667  * in parallel
668  */
669
670 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
671                                                         char *fp, int count)
672 {
673         struct slip *sl = tty->disc_data;
674
675         if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
676                 return;
677
678         /* Read the characters out of the buffer */
679         while (count--) {
680                 if (fp && *fp++) {
681                         if (!test_and_set_bit(SLF_ERROR, &sl->flags))
682                                 sl->dev->stats.rx_errors++;
683                         cp++;
684                         continue;
685                 }
686 #ifdef CONFIG_SLIP_MODE_SLIP6
687                 if (sl->mode & SL_MODE_SLIP6)
688                         slip_unesc6(sl, *cp++);
689                 else
690 #endif
691                         slip_unesc(sl, *cp++);
692         }
693 }
694
695 /************************************
696  *  slip_open helper routines.
697  ************************************/
698
699 /* Collect hanged up channels */
700 static void sl_sync(void)
701 {
702         int i;
703         struct net_device *dev;
704         struct slip       *sl;
705
706         for (i = 0; i < slip_maxdev; i++) {
707                 dev = slip_devs[i];
708                 if (dev == NULL)
709                         break;
710
711                 sl = netdev_priv(dev);
712                 if (sl->tty || sl->leased)
713                         continue;
714                 if (dev->flags & IFF_UP)
715                         dev_close(dev);
716         }
717 }
718
719
720 /* Find a free SLIP channel, and link in this `tty' line. */
721 static struct slip *sl_alloc(dev_t line)
722 {
723         int i;
724         char name[IFNAMSIZ];
725         struct net_device *dev = NULL;
726         struct slip       *sl;
727
728         for (i = 0; i < slip_maxdev; i++) {
729                 dev = slip_devs[i];
730                 if (dev == NULL)
731                         break;
732         }
733         /* Sorry, too many, all slots in use */
734         if (i >= slip_maxdev)
735                 return NULL;
736
737         sprintf(name, "sl%d", i);
738         dev = alloc_netdev(sizeof(*sl), name, sl_setup);
739         if (!dev)
740                 return NULL;
741
742         dev->base_addr  = i;
743         sl = netdev_priv(dev);
744
745         /* Initialize channel control data */
746         sl->magic       = SLIP_MAGIC;
747         sl->dev         = dev;
748         spin_lock_init(&sl->lock);
749         sl->mode        = SL_MODE_DEFAULT;
750 #ifdef CONFIG_SLIP_SMART
751         /* initialize timer_list struct */
752         init_timer(&sl->keepalive_timer);
753         sl->keepalive_timer.data = (unsigned long)sl;
754         sl->keepalive_timer.function = sl_keepalive;
755         init_timer(&sl->outfill_timer);
756         sl->outfill_timer.data = (unsigned long)sl;
757         sl->outfill_timer.function = sl_outfill;
758 #endif
759         slip_devs[i] = dev;
760         return sl;
761 }
762
763 /*
764  * Open the high-level part of the SLIP channel.
765  * This function is called by the TTY module when the
766  * SLIP line discipline is called for.  Because we are
767  * sure the tty line exists, we only have to link it to
768  * a free SLIP channel...
769  *
770  * Called in process context serialized from other ldisc calls.
771  */
772
773 static int slip_open(struct tty_struct *tty)
774 {
775         struct slip *sl;
776         int err;
777
778         if (!capable(CAP_NET_ADMIN))
779                 return -EPERM;
780
781         if (tty->ops->write == NULL)
782                 return -EOPNOTSUPP;
783
784         /* RTnetlink lock is misused here to serialize concurrent
785            opens of slip channels. There are better ways, but it is
786            the simplest one.
787          */
788         rtnl_lock();
789
790         /* Collect hanged up channels. */
791         sl_sync();
792
793         sl = tty->disc_data;
794
795         err = -EEXIST;
796         /* First make sure we're not already connected. */
797         if (sl && sl->magic == SLIP_MAGIC)
798                 goto err_exit;
799
800         /* OK.  Find a free SLIP channel to use. */
801         err = -ENFILE;
802         sl = sl_alloc(tty_devnum(tty));
803         if (sl == NULL)
804                 goto err_exit;
805
806         sl->tty = tty;
807         tty->disc_data = sl;
808         sl->pid = current->pid;
809
810         if (!test_bit(SLF_INUSE, &sl->flags)) {
811                 /* Perform the low-level SLIP initialization. */
812                 err = sl_alloc_bufs(sl, SL_MTU);
813                 if (err)
814                         goto err_free_chan;
815
816                 set_bit(SLF_INUSE, &sl->flags);
817
818                 err = register_netdevice(sl->dev);
819                 if (err)
820                         goto err_free_bufs;
821         }
822
823 #ifdef CONFIG_SLIP_SMART
824         if (sl->keepalive) {
825                 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;
826                 add_timer(&sl->keepalive_timer);
827         }
828         if (sl->outfill) {
829                 sl->outfill_timer.expires = jiffies + sl->outfill * HZ;
830                 add_timer(&sl->outfill_timer);
831         }
832 #endif
833
834         /* Done.  We have linked the TTY line to a channel. */
835         rtnl_unlock();
836         tty->receive_room = 65536;      /* We don't flow control */
837
838         /* TTY layer expects 0 on success */
839         return 0;
840
841 err_free_bufs:
842         sl_free_bufs(sl);
843
844 err_free_chan:
845         sl->tty = NULL;
846         tty->disc_data = NULL;
847         clear_bit(SLF_INUSE, &sl->flags);
848
849 err_exit:
850         rtnl_unlock();
851
852         /* Count references from TTY module */
853         return err;
854 }
855
856 /*
857  * Close down a SLIP channel.
858  * This means flushing out any pending queues, and then returning. This
859  * call is serialized against other ldisc functions.
860  *
861  * We also use this method fo a hangup event
862  */
863
864 static void slip_close(struct tty_struct *tty)
865 {
866         struct slip *sl = tty->disc_data;
867
868         /* First make sure we're connected. */
869         if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
870                 return;
871
872         tty->disc_data = NULL;
873         sl->tty = NULL;
874
875         /* VSV = very important to remove timers */
876 #ifdef CONFIG_SLIP_SMART
877         del_timer_sync(&sl->keepalive_timer);
878         del_timer_sync(&sl->outfill_timer);
879 #endif
880         /* Flush network side */
881         unregister_netdev(sl->dev);
882         /* This will complete via sl_free_netdev */
883 }
884
885 static int slip_hangup(struct tty_struct *tty)
886 {
887         slip_close(tty);
888         return 0;
889 }
890  /************************************************************************
891   *                     STANDARD SLIP ENCAPSULATION                      *
892   ************************************************************************/
893
894 static int slip_esc(unsigned char *s, unsigned char *d, int len)
895 {
896         unsigned char *ptr = d;
897         unsigned char c;
898
899         /*
900          * Send an initial END character to flush out any
901          * data that may have accumulated in the receiver
902          * due to line noise.
903          */
904
905         *ptr++ = END;
906
907         /*
908          * For each byte in the packet, send the appropriate
909          * character sequence, according to the SLIP protocol.
910          */
911
912         while (len-- > 0) {
913                 switch (c = *s++) {
914                 case END:
915                         *ptr++ = ESC;
916                         *ptr++ = ESC_END;
917                         break;
918                 case ESC:
919                         *ptr++ = ESC;
920                         *ptr++ = ESC_ESC;
921                         break;
922                 default:
923                         *ptr++ = c;
924                         break;
925                 }
926         }
927         *ptr++ = END;
928         return ptr - d;
929 }
930
931 static void slip_unesc(struct slip *sl, unsigned char s)
932 {
933
934         switch (s) {
935         case END:
936 #ifdef CONFIG_SLIP_SMART
937                 /* drop keeptest bit = VSV */
938                 if (test_bit(SLF_KEEPTEST, &sl->flags))
939                         clear_bit(SLF_KEEPTEST, &sl->flags);
940 #endif
941
942                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
943                     (sl->rcount > 2))
944                         sl_bump(sl);
945                 clear_bit(SLF_ESCAPE, &sl->flags);
946                 sl->rcount = 0;
947                 return;
948
949         case ESC:
950                 set_bit(SLF_ESCAPE, &sl->flags);
951                 return;
952         case ESC_ESC:
953                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
954                         s = ESC;
955                 break;
956         case ESC_END:
957                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
958                         s = END;
959                 break;
960         }
961         if (!test_bit(SLF_ERROR, &sl->flags))  {
962                 if (sl->rcount < sl->buffsize)  {
963                         sl->rbuff[sl->rcount++] = s;
964                         return;
965                 }
966                 sl->dev->stats.rx_over_errors++;
967                 set_bit(SLF_ERROR, &sl->flags);
968         }
969 }
970
971
972 #ifdef CONFIG_SLIP_MODE_SLIP6
973 /************************************************************************
974  *                       6 BIT SLIP ENCAPSULATION                       *
975  ************************************************************************/
976
977 static int slip_esc6(unsigned char *s, unsigned char *d, int len)
978 {
979         unsigned char *ptr = d;
980         unsigned char c;
981         int i;
982         unsigned short v = 0;
983         short bits = 0;
984
985         /*
986          * Send an initial END character to flush out any
987          * data that may have accumulated in the receiver
988          * due to line noise.
989          */
990
991         *ptr++ = 0x70;
992
993         /*
994          * Encode the packet into printable ascii characters
995          */
996
997         for (i = 0; i < len; ++i) {
998                 v = (v << 8) | s[i];
999                 bits += 8;
1000                 while (bits >= 6) {
1001                         bits -= 6;
1002                         c = 0x30 + ((v >> bits) & 0x3F);
1003                         *ptr++ = c;
1004                 }
1005         }
1006         if (bits) {
1007                 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1008                 *ptr++ = c;
1009         }
1010         *ptr++ = 0x70;
1011         return ptr - d;
1012 }
1013
1014 static void slip_unesc6(struct slip *sl, unsigned char s)
1015 {
1016         unsigned char c;
1017
1018         if (s == 0x70) {
1019 #ifdef CONFIG_SLIP_SMART
1020                 /* drop keeptest bit = VSV */
1021                 if (test_bit(SLF_KEEPTEST, &sl->flags))
1022                         clear_bit(SLF_KEEPTEST, &sl->flags);
1023 #endif
1024
1025                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
1026                     (sl->rcount > 2))
1027                         sl_bump(sl);
1028                 sl->rcount = 0;
1029                 sl->xbits = 0;
1030                 sl->xdata = 0;
1031         } else if (s >= 0x30 && s < 0x70) {
1032                 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1033                 sl->xbits += 6;
1034                 if (sl->xbits >= 8) {
1035                         sl->xbits -= 8;
1036                         c = (unsigned char)(sl->xdata >> sl->xbits);
1037                         if (!test_bit(SLF_ERROR, &sl->flags))  {
1038                                 if (sl->rcount < sl->buffsize)  {
1039                                         sl->rbuff[sl->rcount++] = c;
1040                                         return;
1041                                 }
1042                                 sl->dev->stats.rx_over_errors++;
1043                                 set_bit(SLF_ERROR, &sl->flags);
1044                         }
1045                 }
1046         }
1047 }
1048 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1049
1050 /* Perform I/O control on an active SLIP channel. */
1051 static int slip_ioctl(struct tty_struct *tty, struct file *file,
1052                                         unsigned int cmd, unsigned long arg)
1053 {
1054         struct slip *sl = tty->disc_data;
1055         unsigned int tmp;
1056         int __user *p = (int __user *)arg;
1057
1058         /* First make sure we're connected. */
1059         if (!sl || sl->magic != SLIP_MAGIC)
1060                 return -EINVAL;
1061
1062         switch (cmd) {
1063         case SIOCGIFNAME:
1064                 tmp = strlen(sl->dev->name) + 1;
1065                 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1066                         return -EFAULT;
1067                 return 0;
1068
1069         case SIOCGIFENCAP:
1070                 if (put_user(sl->mode, p))
1071                         return -EFAULT;
1072                 return 0;
1073
1074         case SIOCSIFENCAP:
1075                 if (get_user(tmp, p))
1076                         return -EFAULT;
1077 #ifndef SL_INCLUDE_CSLIP
1078                 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
1079                         return -EINVAL;
1080 #else
1081                 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1082                     (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
1083                         /* return -EINVAL; */
1084                         tmp &= ~SL_MODE_ADAPTIVE;
1085 #endif
1086 #ifndef CONFIG_SLIP_MODE_SLIP6
1087                 if (tmp & SL_MODE_SLIP6)
1088                         return -EINVAL;
1089 #endif
1090                 sl->mode = tmp;
1091                 sl->dev->type = ARPHRD_SLIP + sl->mode;
1092                 return 0;
1093
1094         case SIOCSIFHWADDR:
1095                 return -EINVAL;
1096
1097 #ifdef CONFIG_SLIP_SMART
1098         /* VSV changes start here */
1099         case SIOCSKEEPALIVE:
1100                 if (get_user(tmp, p))
1101                         return -EFAULT;
1102                 if (tmp > 255) /* max for unchar */
1103                         return -EINVAL;
1104
1105                 spin_lock_bh(&sl->lock);
1106                 if (!sl->tty) {
1107                         spin_unlock_bh(&sl->lock);
1108                         return -ENODEV;
1109                 }
1110                 sl->keepalive = (u8)tmp;
1111                 if (sl->keepalive != 0) {
1112                         mod_timer(&sl->keepalive_timer,
1113                                         jiffies + sl->keepalive * HZ);
1114                         set_bit(SLF_KEEPTEST, &sl->flags);
1115                 } else
1116                         del_timer(&sl->keepalive_timer);
1117                 spin_unlock_bh(&sl->lock);
1118                 return 0;
1119
1120         case SIOCGKEEPALIVE:
1121                 if (put_user(sl->keepalive, p))
1122                         return -EFAULT;
1123                 return 0;
1124
1125         case SIOCSOUTFILL:
1126                 if (get_user(tmp, p))
1127                         return -EFAULT;
1128                 if (tmp > 255) /* max for unchar */
1129                         return -EINVAL;
1130                 spin_lock_bh(&sl->lock);
1131                 if (!sl->tty) {
1132                         spin_unlock_bh(&sl->lock);
1133                         return -ENODEV;
1134                 }
1135                 sl->outfill = (u8)tmp;
1136                 if (sl->outfill != 0) {
1137                         mod_timer(&sl->outfill_timer,
1138                                                 jiffies + sl->outfill * HZ);
1139                         set_bit(SLF_OUTWAIT, &sl->flags);
1140                 } else
1141                         del_timer(&sl->outfill_timer);
1142                 spin_unlock_bh(&sl->lock);
1143                 return 0;
1144
1145         case SIOCGOUTFILL:
1146                 if (put_user(sl->outfill, p))
1147                         return -EFAULT;
1148                 return 0;
1149         /* VSV changes end */
1150 #endif
1151         default:
1152                 return tty_mode_ioctl(tty, file, cmd, arg);
1153         }
1154 }
1155
1156 #ifdef CONFIG_COMPAT
1157 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
1158                                         unsigned int cmd, unsigned long arg)
1159 {
1160         switch (cmd) {
1161         case SIOCGIFNAME:
1162         case SIOCGIFENCAP:
1163         case SIOCSIFENCAP:
1164         case SIOCSIFHWADDR:
1165         case SIOCSKEEPALIVE:
1166         case SIOCGKEEPALIVE:
1167         case SIOCSOUTFILL:
1168         case SIOCGOUTFILL:
1169                 return slip_ioctl(tty, file, cmd,
1170                                   (unsigned long)compat_ptr(arg));
1171         }
1172
1173         return -ENOIOCTLCMD;
1174 }
1175 #endif
1176
1177 /* VSV changes start here */
1178 #ifdef CONFIG_SLIP_SMART
1179 /* function do_ioctl called from net/core/dev.c
1180    to allow get/set outfill/keepalive parameter
1181    by ifconfig                                 */
1182
1183 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
1184 {
1185         struct slip *sl = netdev_priv(dev);
1186         unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1187
1188         if (sl == NULL)         /* Allocation failed ?? */
1189                 return -ENODEV;
1190
1191         spin_lock_bh(&sl->lock);
1192
1193         if (!sl->tty) {
1194                 spin_unlock_bh(&sl->lock);
1195                 return -ENODEV;
1196         }
1197
1198         switch (cmd) {
1199         case SIOCSKEEPALIVE:
1200                 /* max for unchar */
1201                 if ((unsigned)*p > 255) {
1202                         spin_unlock_bh(&sl->lock);
1203                         return -EINVAL;
1204                 }
1205                 sl->keepalive = (u8)*p;
1206                 if (sl->keepalive != 0) {
1207                         sl->keepalive_timer.expires =
1208                                                 jiffies + sl->keepalive * HZ;
1209                         mod_timer(&sl->keepalive_timer,
1210                                                 jiffies + sl->keepalive * HZ);
1211                         set_bit(SLF_KEEPTEST, &sl->flags);
1212                 } else
1213                         del_timer(&sl->keepalive_timer);
1214                 break;
1215
1216         case SIOCGKEEPALIVE:
1217                 *p = sl->keepalive;
1218                 break;
1219
1220         case SIOCSOUTFILL:
1221                 if ((unsigned)*p > 255) { /* max for unchar */
1222                         spin_unlock_bh(&sl->lock);
1223                         return -EINVAL;
1224                 }
1225                 sl->outfill = (u8)*p;
1226                 if (sl->outfill != 0) {
1227                         mod_timer(&sl->outfill_timer,
1228                                                 jiffies + sl->outfill * HZ);
1229                         set_bit(SLF_OUTWAIT, &sl->flags);
1230                 } else
1231                         del_timer(&sl->outfill_timer);
1232                 break;
1233
1234         case SIOCGOUTFILL:
1235                 *p = sl->outfill;
1236                 break;
1237
1238         case SIOCSLEASE:
1239                 /* Resolve race condition, when ioctl'ing hanged up
1240                    and opened by another process device.
1241                  */
1242                 if (sl->tty != current->signal->tty &&
1243                                                 sl->pid != current->pid) {
1244                         spin_unlock_bh(&sl->lock);
1245                         return -EPERM;
1246                 }
1247                 sl->leased = 0;
1248                 if (*p)
1249                         sl->leased = 1;
1250                 break;
1251
1252         case SIOCGLEASE:
1253                 *p = sl->leased;
1254         }
1255         spin_unlock_bh(&sl->lock);
1256         return 0;
1257 }
1258 #endif
1259 /* VSV changes end */
1260
1261 static struct tty_ldisc_ops sl_ldisc = {
1262         .owner          = THIS_MODULE,
1263         .magic          = TTY_LDISC_MAGIC,
1264         .name           = "slip",
1265         .open           = slip_open,
1266         .close          = slip_close,
1267         .hangup         = slip_hangup,
1268         .ioctl          = slip_ioctl,
1269 #ifdef CONFIG_COMPAT
1270         .compat_ioctl   = slip_compat_ioctl,
1271 #endif
1272         .receive_buf    = slip_receive_buf,
1273         .write_wakeup   = slip_write_wakeup,
1274 };
1275
1276 static int __init slip_init(void)
1277 {
1278         int status;
1279
1280         if (slip_maxdev < 4)
1281                 slip_maxdev = 4; /* Sanity */
1282
1283         printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1284 #ifdef CONFIG_SLIP_MODE_SLIP6
1285                " (6 bit encapsulation enabled)"
1286 #endif
1287                ".\n",
1288                SLIP_VERSION, slip_maxdev);
1289 #if defined(SL_INCLUDE_CSLIP)
1290         printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1291 #endif
1292 #ifdef CONFIG_SLIP_SMART
1293         printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1294 #endif
1295
1296         slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev,
1297                                                                 GFP_KERNEL);
1298         if (!slip_devs)
1299                 return -ENOMEM;
1300
1301         /* Fill in our line protocol discipline, and register it */
1302         status = tty_register_ldisc(N_SLIP, &sl_ldisc);
1303         if (status != 0) {
1304                 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1305                 kfree(slip_devs);
1306         }
1307         return status;
1308 }
1309
1310 static void __exit slip_exit(void)
1311 {
1312         int i;
1313         struct net_device *dev;
1314         struct slip *sl;
1315         unsigned long timeout = jiffies + HZ;
1316         int busy = 0;
1317
1318         if (slip_devs == NULL)
1319                 return;
1320
1321         /* First of all: check for active disciplines and hangup them.
1322          */
1323         do {
1324                 if (busy)
1325                         msleep_interruptible(100);
1326
1327                 busy = 0;
1328                 for (i = 0; i < slip_maxdev; i++) {
1329                         dev = slip_devs[i];
1330                         if (!dev)
1331                                 continue;
1332                         sl = netdev_priv(dev);
1333                         spin_lock_bh(&sl->lock);
1334                         if (sl->tty) {
1335                                 busy++;
1336                                 tty_hangup(sl->tty);
1337                         }
1338                         spin_unlock_bh(&sl->lock);
1339                 }
1340         } while (busy && time_before(jiffies, timeout));
1341
1342         /* FIXME: hangup is async so we should wait when doing this second
1343            phase */
1344
1345         for (i = 0; i < slip_maxdev; i++) {
1346                 dev = slip_devs[i];
1347                 if (!dev)
1348                         continue;
1349                 slip_devs[i] = NULL;
1350
1351                 sl = netdev_priv(dev);
1352                 if (sl->tty) {
1353                         printk(KERN_ERR "%s: tty discipline still running\n",
1354                                dev->name);
1355                         /* Intentionally leak the control block. */
1356                         dev->destructor = NULL;
1357                 }
1358
1359                 unregister_netdev(dev);
1360         }
1361
1362         kfree(slip_devs);
1363         slip_devs = NULL;
1364
1365         i = tty_unregister_ldisc(N_SLIP);
1366         if (i != 0)
1367                 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1368 }
1369
1370 module_init(slip_init);
1371 module_exit(slip_exit);
1372
1373 #ifdef CONFIG_SLIP_SMART
1374 /*
1375  * This is start of the code for multislip style line checking
1376  * added by Stanislav Voronyi. All changes before marked VSV
1377  */
1378
1379 static void sl_outfill(unsigned long sls)
1380 {
1381         struct slip *sl = (struct slip *)sls;
1382
1383         spin_lock(&sl->lock);
1384
1385         if (sl->tty == NULL)
1386                 goto out;
1387
1388         if (sl->outfill) {
1389                 if (test_bit(SLF_OUTWAIT, &sl->flags)) {
1390                         /* no packets were transmitted, do outfill */
1391 #ifdef CONFIG_SLIP_MODE_SLIP6
1392                         unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1393 #else
1394                         unsigned char s = END;
1395 #endif
1396                         /* put END into tty queue. Is it right ??? */
1397                         if (!netif_queue_stopped(sl->dev)) {
1398                                 /* if device busy no outfill */
1399                                 sl->tty->ops->write(sl->tty, &s, 1);
1400                         }
1401                 } else
1402                         set_bit(SLF_OUTWAIT, &sl->flags);
1403
1404                 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1405         }
1406 out:
1407         spin_unlock(&sl->lock);
1408 }
1409
1410 static void sl_keepalive(unsigned long sls)
1411 {
1412         struct slip *sl = (struct slip *)sls;
1413
1414         spin_lock(&sl->lock);
1415
1416         if (sl->tty == NULL)
1417                 goto out;
1418
1419         if (sl->keepalive) {
1420                 if (test_bit(SLF_KEEPTEST, &sl->flags)) {
1421                         /* keepalive still high :(, we must hangup */
1422                         if (sl->outfill)
1423                                 /* outfill timer must be deleted too */
1424                                 (void)del_timer(&sl->outfill_timer);
1425                         printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1426                         /* this must hangup tty & close slip */
1427                         tty_hangup(sl->tty);
1428                         /* I think we need not something else */
1429                         goto out;
1430                 } else
1431                         set_bit(SLF_KEEPTEST, &sl->flags);
1432
1433                 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1434         }
1435 out:
1436         spin_unlock(&sl->lock);
1437 }
1438
1439 #endif
1440 MODULE_LICENSE("GPL");
1441 MODULE_ALIAS_LDISC(N_SLIP);