bcmdhd: use the wiphy from private data structure (i.e., wl_priv)
[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 <linux/slab.h>
87 #include "slip.h"
88 #ifdef CONFIG_INET
89 #include <linux/ip.h>
90 #include <linux/tcp.h>
91 #include <net/slhc_vj.h>
92 #endif
93
94 #define SLIP_VERSION    "0.8.4-NET3.019-NEWTTY"
95
96 static struct net_device **slip_devs;
97
98 static int slip_maxdev = SL_NRUNIT;
99 module_param(slip_maxdev, int, 0);
100 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
101
102 static int slip_esc(unsigned char *p, unsigned char *d, int len);
103 static void slip_unesc(struct slip *sl, unsigned char c);
104 #ifdef CONFIG_SLIP_MODE_SLIP6
105 static int slip_esc6(unsigned char *p, unsigned char *d, int len);
106 static void slip_unesc6(struct slip *sl, unsigned char c);
107 #endif
108 #ifdef CONFIG_SLIP_SMART
109 static void sl_keepalive(unsigned long sls);
110 static void sl_outfill(unsigned long sls);
111 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
112 #endif
113
114 /********************************
115 *  Buffer administration routines:
116 *       sl_alloc_bufs()
117 *       sl_free_bufs()
118 *       sl_realloc_bufs()
119 *
120 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because
121 *       sl_realloc_bufs provides strong atomicity and reallocation
122 *       on actively running device.
123 *********************************/
124
125 /*
126    Allocate channel buffers.
127  */
128
129 static int sl_alloc_bufs(struct slip *sl, int mtu)
130 {
131         int err = -ENOBUFS;
132         unsigned long len;
133         char *rbuff = NULL;
134         char *xbuff = NULL;
135 #ifdef SL_INCLUDE_CSLIP
136         char *cbuff = NULL;
137         struct slcompress *slcomp = NULL;
138 #endif
139
140         /*
141          * Allocate the SLIP frame buffers:
142          *
143          * rbuff        Receive buffer.
144          * xbuff        Transmit buffer.
145          * cbuff        Temporary compression buffer.
146          */
147         len = mtu * 2;
148
149         /*
150          * allow for arrival of larger UDP packets, even if we say not to
151          * also fixes a bug in which SunOS sends 512-byte packets even with
152          * an MSS of 128
153          */
154         if (len < 576 * 2)
155                 len = 576 * 2;
156         rbuff = kmalloc(len + 4, GFP_KERNEL);
157         if (rbuff == NULL)
158                 goto err_exit;
159         xbuff = kmalloc(len + 4, GFP_KERNEL);
160         if (xbuff == NULL)
161                 goto err_exit;
162 #ifdef SL_INCLUDE_CSLIP
163         cbuff = kmalloc(len + 4, GFP_KERNEL);
164         if (cbuff == NULL)
165                 goto err_exit;
166         slcomp = slhc_init(16, 16);
167         if (slcomp == NULL)
168                 goto err_exit;
169 #endif
170         spin_lock_bh(&sl->lock);
171         if (sl->tty == NULL) {
172                 spin_unlock_bh(&sl->lock);
173                 err = -ENODEV;
174                 goto err_exit;
175         }
176         sl->mtu      = mtu;
177         sl->buffsize = len;
178         sl->rcount   = 0;
179         sl->xleft    = 0;
180         rbuff = xchg(&sl->rbuff, rbuff);
181         xbuff = xchg(&sl->xbuff, xbuff);
182 #ifdef SL_INCLUDE_CSLIP
183         cbuff = xchg(&sl->cbuff, cbuff);
184         slcomp = xchg(&sl->slcomp, slcomp);
185 #endif
186 #ifdef CONFIG_SLIP_MODE_SLIP6
187         sl->xdata    = 0;
188         sl->xbits    = 0;
189 #endif
190         spin_unlock_bh(&sl->lock);
191         err = 0;
192
193         /* Cleanup */
194 err_exit:
195 #ifdef SL_INCLUDE_CSLIP
196         kfree(cbuff);
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                         dev->stats.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                         dev->stats.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 net_device *dev = sl->dev;
322         struct sk_buff *skb;
323         int count;
324
325         count = sl->rcount;
326 #ifdef SL_INCLUDE_CSLIP
327         if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
328                 unsigned char c = sl->rbuff[0];
329                 if (c & SL_TYPE_COMPRESSED_TCP) {
330                         /* ignore compressed packets when CSLIP is off */
331                         if (!(sl->mode & SL_MODE_CSLIP)) {
332                                 printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name);
333                                 return;
334                         }
335                         /* make sure we've reserved enough space for uncompress
336                            to use */
337                         if (count + 80 > sl->buffsize) {
338                                 dev->stats.rx_over_errors++;
339                                 return;
340                         }
341                         count = slhc_uncompress(sl->slcomp, sl->rbuff, count);
342                         if (count <= 0)
343                                 return;
344                 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {
345                         if (!(sl->mode & SL_MODE_CSLIP)) {
346                                 /* turn on header compression */
347                                 sl->mode |= SL_MODE_CSLIP;
348                                 sl->mode &= ~SL_MODE_ADAPTIVE;
349                                 printk(KERN_INFO "%s: header compression turned on\n", dev->name);
350                         }
351                         sl->rbuff[0] &= 0x4f;
352                         if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0)
353                                 return;
354                 }
355         }
356 #endif  /* SL_INCLUDE_CSLIP */
357
358         dev->stats.rx_bytes += count;
359
360         skb = dev_alloc_skb(count);
361         if (skb == NULL) {
362                 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name);
363                 dev->stats.rx_dropped++;
364                 return;
365         }
366         skb->dev = dev;
367         memcpy(skb_put(skb, count), sl->rbuff, count);
368         skb_reset_mac_header(skb);
369         skb->protocol = htons(ETH_P_IP);
370         netif_rx_ni(skb);
371         dev->stats.rx_packets++;
372 }
373
374 /* Encapsulate one IP datagram and stuff into a TTY queue. */
375 static void sl_encaps(struct slip *sl, unsigned char *icp, int len)
376 {
377         unsigned char *p;
378         int actual, count;
379
380         if (len > sl->mtu) {            /* Sigh, shouldn't occur BUT ... */
381                 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name);
382                 sl->dev->stats.tx_dropped++;
383                 sl_unlock(sl);
384                 return;
385         }
386
387         p = icp;
388 #ifdef SL_INCLUDE_CSLIP
389         if (sl->mode & SL_MODE_CSLIP)
390                 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);
391 #endif
392 #ifdef CONFIG_SLIP_MODE_SLIP6
393         if (sl->mode & SL_MODE_SLIP6)
394                 count = slip_esc6(p, (unsigned char *) sl->xbuff, len);
395         else
396 #endif
397                 count = slip_esc(p, (unsigned char *) sl->xbuff, len);
398
399         /* Order of next two lines is *very* important.
400          * When we are sending a little amount of data,
401          * the transfer may be completed inside the ops->write()
402          * routine, because it's running with interrupts enabled.
403          * In this case we *never* got WRITE_WAKEUP event,
404          * if we did not request it before write operation.
405          *       14 Oct 1994  Dmitry Gorodchanin.
406          */
407         set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
408         actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
409 #ifdef SL_CHECK_TRANSMIT
410         sl->dev->trans_start = jiffies;
411 #endif
412         sl->xleft = count - actual;
413         sl->xhead = sl->xbuff + actual;
414 #ifdef CONFIG_SLIP_SMART
415         /* VSV */
416         clear_bit(SLF_OUTWAIT, &sl->flags);     /* reset outfill flag */
417 #endif
418 }
419
420 /*
421  * Called by the driver when there's room for more data.  If we have
422  * more packets to send, we send them here.
423  */
424 static void slip_write_wakeup(struct tty_struct *tty)
425 {
426         int actual;
427         struct slip *sl = tty->disc_data;
428
429         /* First make sure we're connected. */
430         if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
431                 return;
432
433         if (sl->xleft <= 0)  {
434                 /* Now serial buffer is almost free & we can start
435                  * transmission of another packet */
436                 sl->dev->stats.tx_packets++;
437                 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
438                 sl_unlock(sl);
439                 return;
440         }
441
442         actual = tty->ops->write(tty, sl->xhead, sl->xleft);
443         sl->xleft -= actual;
444         sl->xhead += actual;
445 }
446
447 static void sl_tx_timeout(struct net_device *dev)
448 {
449         struct slip *sl = netdev_priv(dev);
450
451         spin_lock(&sl->lock);
452
453         if (netif_queue_stopped(dev)) {
454                 if (!netif_running(dev))
455                         goto out;
456
457                 /* May be we must check transmitter timeout here ?
458                  *      14 Oct 1994 Dmitry Gorodchanin.
459                  */
460 #ifdef SL_CHECK_TRANSMIT
461                 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ))  {
462                         /* 20 sec timeout not reached */
463                         goto out;
464                 }
465                 printk(KERN_WARNING "%s: transmit timed out, %s?\n",
466                         dev->name,
467                         (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
468                                 "bad line quality" : "driver error");
469                 sl->xleft = 0;
470                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
471                 sl_unlock(sl);
472 #endif
473         }
474 out:
475         spin_unlock(&sl->lock);
476 }
477
478
479 /* Encapsulate an IP datagram and kick it into a TTY queue. */
480 static netdev_tx_t
481 sl_xmit(struct sk_buff *skb, struct net_device *dev)
482 {
483         struct slip *sl = netdev_priv(dev);
484
485         spin_lock(&sl->lock);
486         if (!netif_running(dev)) {
487                 spin_unlock(&sl->lock);
488                 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
489                 dev_kfree_skb(skb);
490                 return NETDEV_TX_OK;
491         }
492         if (sl->tty == NULL) {
493                 spin_unlock(&sl->lock);
494                 dev_kfree_skb(skb);
495                 return NETDEV_TX_OK;
496         }
497
498         sl_lock(sl);
499         dev->stats.tx_bytes += skb->len;
500         sl_encaps(sl, skb->data, skb->len);
501         spin_unlock(&sl->lock);
502
503         dev_kfree_skb(skb);
504         return NETDEV_TX_OK;
505 }
506
507
508 /******************************************
509  *   Routines looking at netdevice side.
510  ******************************************/
511
512 /* Netdevice UP -> DOWN routine */
513
514 static int
515 sl_close(struct net_device *dev)
516 {
517         struct slip *sl = netdev_priv(dev);
518
519         spin_lock_bh(&sl->lock);
520         if (sl->tty)
521                 /* TTY discipline is running. */
522                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
523         netif_stop_queue(dev);
524         sl->rcount   = 0;
525         sl->xleft    = 0;
526         spin_unlock_bh(&sl->lock);
527
528         return 0;
529 }
530
531 /* Netdevice DOWN -> UP routine */
532
533 static int sl_open(struct net_device *dev)
534 {
535         struct slip *sl = netdev_priv(dev);
536
537         if (sl->tty == NULL)
538                 return -ENODEV;
539
540         sl->flags &= (1 << SLF_INUSE);
541         netif_start_queue(dev);
542         return 0;
543 }
544
545 /* Netdevice change MTU request */
546
547 static int sl_change_mtu(struct net_device *dev, int new_mtu)
548 {
549         struct slip *sl = netdev_priv(dev);
550
551         if (new_mtu < 68 || new_mtu > 65534)
552                 return -EINVAL;
553
554         if (new_mtu != dev->mtu)
555                 return sl_realloc_bufs(sl, new_mtu);
556         return 0;
557 }
558
559 /* Netdevice get statistics request */
560
561 static struct rtnl_link_stats64 *
562 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
563 {
564         struct net_device_stats *devstats = &dev->stats;
565         unsigned long c_rx_dropped = 0;
566 #ifdef SL_INCLUDE_CSLIP
567         unsigned long c_rx_fifo_errors = 0;
568         unsigned long c_tx_fifo_errors = 0;
569         unsigned long c_collisions = 0;
570         struct slip *sl = netdev_priv(dev);
571         struct slcompress *comp = sl->slcomp;
572
573         if (comp) {
574                 c_rx_fifo_errors = comp->sls_i_compressed;
575                 c_rx_dropped     = comp->sls_i_tossed;
576                 c_tx_fifo_errors = comp->sls_o_compressed;
577                 c_collisions     = comp->sls_o_misses;
578         }
579         stats->rx_fifo_errors = sl->rx_compressed + c_rx_fifo_errors;
580         stats->tx_fifo_errors = sl->tx_compressed + c_tx_fifo_errors;
581         stats->collisions     = sl->tx_misses + c_collisions;
582 #endif
583         stats->rx_packets     = devstats->rx_packets;
584         stats->tx_packets     = devstats->tx_packets;
585         stats->rx_bytes       = devstats->rx_bytes;
586         stats->tx_bytes       = devstats->tx_bytes;
587         stats->rx_dropped     = devstats->rx_dropped + c_rx_dropped;
588         stats->tx_dropped     = devstats->tx_dropped;
589         stats->tx_errors      = devstats->tx_errors;
590         stats->rx_errors      = devstats->rx_errors;
591         stats->rx_over_errors = devstats->rx_over_errors;
592
593         return stats;
594 }
595
596 /* Netdevice register callback */
597
598 static int sl_init(struct net_device *dev)
599 {
600         struct slip *sl = netdev_priv(dev);
601
602         /*
603          *      Finish setting up the DEVICE info.
604          */
605
606         dev->mtu                = sl->mtu;
607         dev->type               = ARPHRD_SLIP + sl->mode;
608 #ifdef SL_CHECK_TRANSMIT
609         dev->watchdog_timeo     = 20*HZ;
610 #endif
611         return 0;
612 }
613
614
615 static void sl_uninit(struct net_device *dev)
616 {
617         struct slip *sl = netdev_priv(dev);
618
619         sl_free_bufs(sl);
620 }
621
622 /* Hook the destructor so we can free slip devices at the right point in time */
623 static void sl_free_netdev(struct net_device *dev)
624 {
625         int i = dev->base_addr;
626         free_netdev(dev);
627         slip_devs[i] = NULL;
628 }
629
630 static const struct net_device_ops sl_netdev_ops = {
631         .ndo_init               = sl_init,
632         .ndo_uninit             = sl_uninit,
633         .ndo_open               = sl_open,
634         .ndo_stop               = sl_close,
635         .ndo_start_xmit         = sl_xmit,
636         .ndo_get_stats64        = sl_get_stats64,
637         .ndo_change_mtu         = sl_change_mtu,
638         .ndo_tx_timeout         = sl_tx_timeout,
639 #ifdef CONFIG_SLIP_SMART
640         .ndo_do_ioctl           = sl_ioctl,
641 #endif
642 };
643
644
645 static void sl_setup(struct net_device *dev)
646 {
647         dev->netdev_ops         = &sl_netdev_ops;
648         dev->destructor         = sl_free_netdev;
649
650         dev->hard_header_len    = 0;
651         dev->addr_len           = 0;
652         dev->tx_queue_len       = 10;
653
654         /* New-style flags. */
655         dev->flags              = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
656 }
657
658 /******************************************
659   Routines looking at TTY side.
660  ******************************************/
661
662
663 /*
664  * Handle the 'receiver data ready' interrupt.
665  * This function is called by the 'tty_io' module in the kernel when
666  * a block of SLIP data has been received, which can now be decapsulated
667  * and sent on to some IP layer for further processing. This will not
668  * be re-entered while running but other ldisc functions may be called
669  * in parallel
670  */
671
672 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
673                                                         char *fp, int count)
674 {
675         struct slip *sl = tty->disc_data;
676
677         if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
678                 return;
679
680         /* Read the characters out of the buffer */
681         while (count--) {
682                 if (fp && *fp++) {
683                         if (!test_and_set_bit(SLF_ERROR, &sl->flags))
684                                 sl->dev->stats.rx_errors++;
685                         cp++;
686                         continue;
687                 }
688 #ifdef CONFIG_SLIP_MODE_SLIP6
689                 if (sl->mode & SL_MODE_SLIP6)
690                         slip_unesc6(sl, *cp++);
691                 else
692 #endif
693                         slip_unesc(sl, *cp++);
694         }
695 }
696
697 /************************************
698  *  slip_open helper routines.
699  ************************************/
700
701 /* Collect hanged up channels */
702 static void sl_sync(void)
703 {
704         int i;
705         struct net_device *dev;
706         struct slip       *sl;
707
708         for (i = 0; i < slip_maxdev; i++) {
709                 dev = slip_devs[i];
710                 if (dev == NULL)
711                         break;
712
713                 sl = netdev_priv(dev);
714                 if (sl->tty || sl->leased)
715                         continue;
716                 if (dev->flags & IFF_UP)
717                         dev_close(dev);
718         }
719 }
720
721
722 /* Find a free SLIP channel, and link in this `tty' line. */
723 static struct slip *sl_alloc(dev_t line)
724 {
725         int i;
726         char name[IFNAMSIZ];
727         struct net_device *dev = NULL;
728         struct slip       *sl;
729
730         for (i = 0; i < slip_maxdev; i++) {
731                 dev = slip_devs[i];
732                 if (dev == NULL)
733                         break;
734         }
735         /* Sorry, too many, all slots in use */
736         if (i >= slip_maxdev)
737                 return NULL;
738
739         sprintf(name, "sl%d", i);
740         dev = alloc_netdev(sizeof(*sl), name, sl_setup);
741         if (!dev)
742                 return NULL;
743
744         dev->base_addr  = i;
745         sl = netdev_priv(dev);
746
747         /* Initialize channel control data */
748         sl->magic       = SLIP_MAGIC;
749         sl->dev         = dev;
750         spin_lock_init(&sl->lock);
751         sl->mode        = SL_MODE_DEFAULT;
752 #ifdef CONFIG_SLIP_SMART
753         /* initialize timer_list struct */
754         init_timer(&sl->keepalive_timer);
755         sl->keepalive_timer.data = (unsigned long)sl;
756         sl->keepalive_timer.function = sl_keepalive;
757         init_timer(&sl->outfill_timer);
758         sl->outfill_timer.data = (unsigned long)sl;
759         sl->outfill_timer.function = sl_outfill;
760 #endif
761         slip_devs[i] = dev;
762         return sl;
763 }
764
765 /*
766  * Open the high-level part of the SLIP channel.
767  * This function is called by the TTY module when the
768  * SLIP line discipline is called for.  Because we are
769  * sure the tty line exists, we only have to link it to
770  * a free SLIP channel...
771  *
772  * Called in process context serialized from other ldisc calls.
773  */
774
775 static int slip_open(struct tty_struct *tty)
776 {
777         struct slip *sl;
778         int err;
779
780         if (!capable(CAP_NET_ADMIN))
781                 return -EPERM;
782
783         if (tty->ops->write == NULL)
784                 return -EOPNOTSUPP;
785
786         /* RTnetlink lock is misused here to serialize concurrent
787            opens of slip channels. There are better ways, but it is
788            the simplest one.
789          */
790         rtnl_lock();
791
792         /* Collect hanged up channels. */
793         sl_sync();
794
795         sl = tty->disc_data;
796
797         err = -EEXIST;
798         /* First make sure we're not already connected. */
799         if (sl && sl->magic == SLIP_MAGIC)
800                 goto err_exit;
801
802         /* OK.  Find a free SLIP channel to use. */
803         err = -ENFILE;
804         sl = sl_alloc(tty_devnum(tty));
805         if (sl == NULL)
806                 goto err_exit;
807
808         sl->tty = tty;
809         tty->disc_data = sl;
810         sl->pid = current->pid;
811
812         if (!test_bit(SLF_INUSE, &sl->flags)) {
813                 /* Perform the low-level SLIP initialization. */
814                 err = sl_alloc_bufs(sl, SL_MTU);
815                 if (err)
816                         goto err_free_chan;
817
818                 set_bit(SLF_INUSE, &sl->flags);
819
820                 err = register_netdevice(sl->dev);
821                 if (err)
822                         goto err_free_bufs;
823         }
824
825 #ifdef CONFIG_SLIP_SMART
826         if (sl->keepalive) {
827                 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;
828                 add_timer(&sl->keepalive_timer);
829         }
830         if (sl->outfill) {
831                 sl->outfill_timer.expires = jiffies + sl->outfill * HZ;
832                 add_timer(&sl->outfill_timer);
833         }
834 #endif
835
836         /* Done.  We have linked the TTY line to a channel. */
837         rtnl_unlock();
838         tty->receive_room = 65536;      /* We don't flow control */
839
840         /* TTY layer expects 0 on success */
841         return 0;
842
843 err_free_bufs:
844         sl_free_bufs(sl);
845
846 err_free_chan:
847         sl->tty = NULL;
848         tty->disc_data = NULL;
849         clear_bit(SLF_INUSE, &sl->flags);
850
851 err_exit:
852         rtnl_unlock();
853
854         /* Count references from TTY module */
855         return err;
856 }
857
858 /*
859  * Close down a SLIP channel.
860  * This means flushing out any pending queues, and then returning. This
861  * call is serialized against other ldisc functions.
862  *
863  * We also use this method fo a hangup event
864  */
865
866 static void slip_close(struct tty_struct *tty)
867 {
868         struct slip *sl = tty->disc_data;
869
870         /* First make sure we're connected. */
871         if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
872                 return;
873
874         tty->disc_data = NULL;
875         sl->tty = NULL;
876
877         /* VSV = very important to remove timers */
878 #ifdef CONFIG_SLIP_SMART
879         del_timer_sync(&sl->keepalive_timer);
880         del_timer_sync(&sl->outfill_timer);
881 #endif
882         /* Flush network side */
883         unregister_netdev(sl->dev);
884         /* This will complete via sl_free_netdev */
885 }
886
887 static int slip_hangup(struct tty_struct *tty)
888 {
889         slip_close(tty);
890         return 0;
891 }
892  /************************************************************************
893   *                     STANDARD SLIP ENCAPSULATION                      *
894   ************************************************************************/
895
896 static int slip_esc(unsigned char *s, unsigned char *d, int len)
897 {
898         unsigned char *ptr = d;
899         unsigned char c;
900
901         /*
902          * Send an initial END character to flush out any
903          * data that may have accumulated in the receiver
904          * due to line noise.
905          */
906
907         *ptr++ = END;
908
909         /*
910          * For each byte in the packet, send the appropriate
911          * character sequence, according to the SLIP protocol.
912          */
913
914         while (len-- > 0) {
915                 switch (c = *s++) {
916                 case END:
917                         *ptr++ = ESC;
918                         *ptr++ = ESC_END;
919                         break;
920                 case ESC:
921                         *ptr++ = ESC;
922                         *ptr++ = ESC_ESC;
923                         break;
924                 default:
925                         *ptr++ = c;
926                         break;
927                 }
928         }
929         *ptr++ = END;
930         return ptr - d;
931 }
932
933 static void slip_unesc(struct slip *sl, unsigned char s)
934 {
935
936         switch (s) {
937         case END:
938 #ifdef CONFIG_SLIP_SMART
939                 /* drop keeptest bit = VSV */
940                 if (test_bit(SLF_KEEPTEST, &sl->flags))
941                         clear_bit(SLF_KEEPTEST, &sl->flags);
942 #endif
943
944                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
945                     (sl->rcount > 2))
946                         sl_bump(sl);
947                 clear_bit(SLF_ESCAPE, &sl->flags);
948                 sl->rcount = 0;
949                 return;
950
951         case ESC:
952                 set_bit(SLF_ESCAPE, &sl->flags);
953                 return;
954         case ESC_ESC:
955                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
956                         s = ESC;
957                 break;
958         case ESC_END:
959                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
960                         s = END;
961                 break;
962         }
963         if (!test_bit(SLF_ERROR, &sl->flags))  {
964                 if (sl->rcount < sl->buffsize)  {
965                         sl->rbuff[sl->rcount++] = s;
966                         return;
967                 }
968                 sl->dev->stats.rx_over_errors++;
969                 set_bit(SLF_ERROR, &sl->flags);
970         }
971 }
972
973
974 #ifdef CONFIG_SLIP_MODE_SLIP6
975 /************************************************************************
976  *                       6 BIT SLIP ENCAPSULATION                       *
977  ************************************************************************/
978
979 static int slip_esc6(unsigned char *s, unsigned char *d, int len)
980 {
981         unsigned char *ptr = d;
982         unsigned char c;
983         int i;
984         unsigned short v = 0;
985         short bits = 0;
986
987         /*
988          * Send an initial END character to flush out any
989          * data that may have accumulated in the receiver
990          * due to line noise.
991          */
992
993         *ptr++ = 0x70;
994
995         /*
996          * Encode the packet into printable ascii characters
997          */
998
999         for (i = 0; i < len; ++i) {
1000                 v = (v << 8) | s[i];
1001                 bits += 8;
1002                 while (bits >= 6) {
1003                         bits -= 6;
1004                         c = 0x30 + ((v >> bits) & 0x3F);
1005                         *ptr++ = c;
1006                 }
1007         }
1008         if (bits) {
1009                 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1010                 *ptr++ = c;
1011         }
1012         *ptr++ = 0x70;
1013         return ptr - d;
1014 }
1015
1016 static void slip_unesc6(struct slip *sl, unsigned char s)
1017 {
1018         unsigned char c;
1019
1020         if (s == 0x70) {
1021 #ifdef CONFIG_SLIP_SMART
1022                 /* drop keeptest bit = VSV */
1023                 if (test_bit(SLF_KEEPTEST, &sl->flags))
1024                         clear_bit(SLF_KEEPTEST, &sl->flags);
1025 #endif
1026
1027                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
1028                     (sl->rcount > 2))
1029                         sl_bump(sl);
1030                 sl->rcount = 0;
1031                 sl->xbits = 0;
1032                 sl->xdata = 0;
1033         } else if (s >= 0x30 && s < 0x70) {
1034                 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1035                 sl->xbits += 6;
1036                 if (sl->xbits >= 8) {
1037                         sl->xbits -= 8;
1038                         c = (unsigned char)(sl->xdata >> sl->xbits);
1039                         if (!test_bit(SLF_ERROR, &sl->flags))  {
1040                                 if (sl->rcount < sl->buffsize)  {
1041                                         sl->rbuff[sl->rcount++] = c;
1042                                         return;
1043                                 }
1044                                 sl->dev->stats.rx_over_errors++;
1045                                 set_bit(SLF_ERROR, &sl->flags);
1046                         }
1047                 }
1048         }
1049 }
1050 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1051
1052 /* Perform I/O control on an active SLIP channel. */
1053 static int slip_ioctl(struct tty_struct *tty, struct file *file,
1054                                         unsigned int cmd, unsigned long arg)
1055 {
1056         struct slip *sl = tty->disc_data;
1057         unsigned int tmp;
1058         int __user *p = (int __user *)arg;
1059
1060         /* First make sure we're connected. */
1061         if (!sl || sl->magic != SLIP_MAGIC)
1062                 return -EINVAL;
1063
1064         switch (cmd) {
1065         case SIOCGIFNAME:
1066                 tmp = strlen(sl->dev->name) + 1;
1067                 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1068                         return -EFAULT;
1069                 return 0;
1070
1071         case SIOCGIFENCAP:
1072                 if (put_user(sl->mode, p))
1073                         return -EFAULT;
1074                 return 0;
1075
1076         case SIOCSIFENCAP:
1077                 if (get_user(tmp, p))
1078                         return -EFAULT;
1079 #ifndef SL_INCLUDE_CSLIP
1080                 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
1081                         return -EINVAL;
1082 #else
1083                 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1084                     (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
1085                         /* return -EINVAL; */
1086                         tmp &= ~SL_MODE_ADAPTIVE;
1087 #endif
1088 #ifndef CONFIG_SLIP_MODE_SLIP6
1089                 if (tmp & SL_MODE_SLIP6)
1090                         return -EINVAL;
1091 #endif
1092                 sl->mode = tmp;
1093                 sl->dev->type = ARPHRD_SLIP + sl->mode;
1094                 return 0;
1095
1096         case SIOCSIFHWADDR:
1097                 return -EINVAL;
1098
1099 #ifdef CONFIG_SLIP_SMART
1100         /* VSV changes start here */
1101         case SIOCSKEEPALIVE:
1102                 if (get_user(tmp, p))
1103                         return -EFAULT;
1104                 if (tmp > 255) /* max for unchar */
1105                         return -EINVAL;
1106
1107                 spin_lock_bh(&sl->lock);
1108                 if (!sl->tty) {
1109                         spin_unlock_bh(&sl->lock);
1110                         return -ENODEV;
1111                 }
1112                 sl->keepalive = (u8)tmp;
1113                 if (sl->keepalive != 0) {
1114                         mod_timer(&sl->keepalive_timer,
1115                                         jiffies + sl->keepalive * HZ);
1116                         set_bit(SLF_KEEPTEST, &sl->flags);
1117                 } else
1118                         del_timer(&sl->keepalive_timer);
1119                 spin_unlock_bh(&sl->lock);
1120                 return 0;
1121
1122         case SIOCGKEEPALIVE:
1123                 if (put_user(sl->keepalive, p))
1124                         return -EFAULT;
1125                 return 0;
1126
1127         case SIOCSOUTFILL:
1128                 if (get_user(tmp, p))
1129                         return -EFAULT;
1130                 if (tmp > 255) /* max for unchar */
1131                         return -EINVAL;
1132                 spin_lock_bh(&sl->lock);
1133                 if (!sl->tty) {
1134                         spin_unlock_bh(&sl->lock);
1135                         return -ENODEV;
1136                 }
1137                 sl->outfill = (u8)tmp;
1138                 if (sl->outfill != 0) {
1139                         mod_timer(&sl->outfill_timer,
1140                                                 jiffies + sl->outfill * HZ);
1141                         set_bit(SLF_OUTWAIT, &sl->flags);
1142                 } else
1143                         del_timer(&sl->outfill_timer);
1144                 spin_unlock_bh(&sl->lock);
1145                 return 0;
1146
1147         case SIOCGOUTFILL:
1148                 if (put_user(sl->outfill, p))
1149                         return -EFAULT;
1150                 return 0;
1151         /* VSV changes end */
1152 #endif
1153         default:
1154                 return tty_mode_ioctl(tty, file, cmd, arg);
1155         }
1156 }
1157
1158 #ifdef CONFIG_COMPAT
1159 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
1160                                         unsigned int cmd, unsigned long arg)
1161 {
1162         switch (cmd) {
1163         case SIOCGIFNAME:
1164         case SIOCGIFENCAP:
1165         case SIOCSIFENCAP:
1166         case SIOCSIFHWADDR:
1167         case SIOCSKEEPALIVE:
1168         case SIOCGKEEPALIVE:
1169         case SIOCSOUTFILL:
1170         case SIOCGOUTFILL:
1171                 return slip_ioctl(tty, file, cmd,
1172                                   (unsigned long)compat_ptr(arg));
1173         }
1174
1175         return -ENOIOCTLCMD;
1176 }
1177 #endif
1178
1179 /* VSV changes start here */
1180 #ifdef CONFIG_SLIP_SMART
1181 /* function do_ioctl called from net/core/dev.c
1182    to allow get/set outfill/keepalive parameter
1183    by ifconfig                                 */
1184
1185 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
1186 {
1187         struct slip *sl = netdev_priv(dev);
1188         unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1189
1190         if (sl == NULL)         /* Allocation failed ?? */
1191                 return -ENODEV;
1192
1193         spin_lock_bh(&sl->lock);
1194
1195         if (!sl->tty) {
1196                 spin_unlock_bh(&sl->lock);
1197                 return -ENODEV;
1198         }
1199
1200         switch (cmd) {
1201         case SIOCSKEEPALIVE:
1202                 /* max for unchar */
1203                 if ((unsigned)*p > 255) {
1204                         spin_unlock_bh(&sl->lock);
1205                         return -EINVAL;
1206                 }
1207                 sl->keepalive = (u8)*p;
1208                 if (sl->keepalive != 0) {
1209                         sl->keepalive_timer.expires =
1210                                                 jiffies + sl->keepalive * HZ;
1211                         mod_timer(&sl->keepalive_timer,
1212                                                 jiffies + sl->keepalive * HZ);
1213                         set_bit(SLF_KEEPTEST, &sl->flags);
1214                 } else
1215                         del_timer(&sl->keepalive_timer);
1216                 break;
1217
1218         case SIOCGKEEPALIVE:
1219                 *p = sl->keepalive;
1220                 break;
1221
1222         case SIOCSOUTFILL:
1223                 if ((unsigned)*p > 255) { /* max for unchar */
1224                         spin_unlock_bh(&sl->lock);
1225                         return -EINVAL;
1226                 }
1227                 sl->outfill = (u8)*p;
1228                 if (sl->outfill != 0) {
1229                         mod_timer(&sl->outfill_timer,
1230                                                 jiffies + sl->outfill * HZ);
1231                         set_bit(SLF_OUTWAIT, &sl->flags);
1232                 } else
1233                         del_timer(&sl->outfill_timer);
1234                 break;
1235
1236         case SIOCGOUTFILL:
1237                 *p = sl->outfill;
1238                 break;
1239
1240         case SIOCSLEASE:
1241                 /* Resolve race condition, when ioctl'ing hanged up
1242                    and opened by another process device.
1243                  */
1244                 if (sl->tty != current->signal->tty &&
1245                                                 sl->pid != current->pid) {
1246                         spin_unlock_bh(&sl->lock);
1247                         return -EPERM;
1248                 }
1249                 sl->leased = 0;
1250                 if (*p)
1251                         sl->leased = 1;
1252                 break;
1253
1254         case SIOCGLEASE:
1255                 *p = sl->leased;
1256         }
1257         spin_unlock_bh(&sl->lock);
1258         return 0;
1259 }
1260 #endif
1261 /* VSV changes end */
1262
1263 static struct tty_ldisc_ops sl_ldisc = {
1264         .owner          = THIS_MODULE,
1265         .magic          = TTY_LDISC_MAGIC,
1266         .name           = "slip",
1267         .open           = slip_open,
1268         .close          = slip_close,
1269         .hangup         = slip_hangup,
1270         .ioctl          = slip_ioctl,
1271 #ifdef CONFIG_COMPAT
1272         .compat_ioctl   = slip_compat_ioctl,
1273 #endif
1274         .receive_buf    = slip_receive_buf,
1275         .write_wakeup   = slip_write_wakeup,
1276 };
1277
1278 static int __init slip_init(void)
1279 {
1280         int status;
1281
1282         if (slip_maxdev < 4)
1283                 slip_maxdev = 4; /* Sanity */
1284
1285         printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1286 #ifdef CONFIG_SLIP_MODE_SLIP6
1287                " (6 bit encapsulation enabled)"
1288 #endif
1289                ".\n",
1290                SLIP_VERSION, slip_maxdev);
1291 #if defined(SL_INCLUDE_CSLIP)
1292         printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1293 #endif
1294 #ifdef CONFIG_SLIP_SMART
1295         printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1296 #endif
1297
1298         slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev,
1299                                                                 GFP_KERNEL);
1300         if (!slip_devs) {
1301                 printk(KERN_ERR "SLIP: Can't allocate slip devices array.\n");
1302                 return -ENOMEM;
1303         }
1304
1305         /* Fill in our line protocol discipline, and register it */
1306         status = tty_register_ldisc(N_SLIP, &sl_ldisc);
1307         if (status != 0) {
1308                 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1309                 kfree(slip_devs);
1310         }
1311         return status;
1312 }
1313
1314 static void __exit slip_exit(void)
1315 {
1316         int i;
1317         struct net_device *dev;
1318         struct slip *sl;
1319         unsigned long timeout = jiffies + HZ;
1320         int busy = 0;
1321
1322         if (slip_devs == NULL)
1323                 return;
1324
1325         /* First of all: check for active disciplines and hangup them.
1326          */
1327         do {
1328                 if (busy)
1329                         msleep_interruptible(100);
1330
1331                 busy = 0;
1332                 for (i = 0; i < slip_maxdev; i++) {
1333                         dev = slip_devs[i];
1334                         if (!dev)
1335                                 continue;
1336                         sl = netdev_priv(dev);
1337                         spin_lock_bh(&sl->lock);
1338                         if (sl->tty) {
1339                                 busy++;
1340                                 tty_hangup(sl->tty);
1341                         }
1342                         spin_unlock_bh(&sl->lock);
1343                 }
1344         } while (busy && time_before(jiffies, timeout));
1345
1346         /* FIXME: hangup is async so we should wait when doing this second
1347            phase */
1348
1349         for (i = 0; i < slip_maxdev; i++) {
1350                 dev = slip_devs[i];
1351                 if (!dev)
1352                         continue;
1353                 slip_devs[i] = NULL;
1354
1355                 sl = netdev_priv(dev);
1356                 if (sl->tty) {
1357                         printk(KERN_ERR "%s: tty discipline still running\n",
1358                                dev->name);
1359                         /* Intentionally leak the control block. */
1360                         dev->destructor = NULL;
1361                 }
1362
1363                 unregister_netdev(dev);
1364         }
1365
1366         kfree(slip_devs);
1367         slip_devs = NULL;
1368
1369         i = tty_unregister_ldisc(N_SLIP);
1370         if (i != 0)
1371                 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1372 }
1373
1374 module_init(slip_init);
1375 module_exit(slip_exit);
1376
1377 #ifdef CONFIG_SLIP_SMART
1378 /*
1379  * This is start of the code for multislip style line checking
1380  * added by Stanislav Voronyi. All changes before marked VSV
1381  */
1382
1383 static void sl_outfill(unsigned long sls)
1384 {
1385         struct slip *sl = (struct slip *)sls;
1386
1387         spin_lock(&sl->lock);
1388
1389         if (sl->tty == NULL)
1390                 goto out;
1391
1392         if (sl->outfill) {
1393                 if (test_bit(SLF_OUTWAIT, &sl->flags)) {
1394                         /* no packets were transmitted, do outfill */
1395 #ifdef CONFIG_SLIP_MODE_SLIP6
1396                         unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1397 #else
1398                         unsigned char s = END;
1399 #endif
1400                         /* put END into tty queue. Is it right ??? */
1401                         if (!netif_queue_stopped(sl->dev)) {
1402                                 /* if device busy no outfill */
1403                                 sl->tty->ops->write(sl->tty, &s, 1);
1404                         }
1405                 } else
1406                         set_bit(SLF_OUTWAIT, &sl->flags);
1407
1408                 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1409         }
1410 out:
1411         spin_unlock(&sl->lock);
1412 }
1413
1414 static void sl_keepalive(unsigned long sls)
1415 {
1416         struct slip *sl = (struct slip *)sls;
1417
1418         spin_lock(&sl->lock);
1419
1420         if (sl->tty == NULL)
1421                 goto out;
1422
1423         if (sl->keepalive) {
1424                 if (test_bit(SLF_KEEPTEST, &sl->flags)) {
1425                         /* keepalive still high :(, we must hangup */
1426                         if (sl->outfill)
1427                                 /* outfill timer must be deleted too */
1428                                 (void)del_timer(&sl->outfill_timer);
1429                         printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1430                         /* this must hangup tty & close slip */
1431                         tty_hangup(sl->tty);
1432                         /* I think we need not something else */
1433                         goto out;
1434                 } else
1435                         set_bit(SLF_KEEPTEST, &sl->flags);
1436
1437                 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1438         }
1439 out:
1440         spin_unlock(&sl->lock);
1441 }
1442
1443 #endif
1444 MODULE_LICENSE("GPL");
1445 MODULE_ALIAS_LDISC(N_SLIP);