86cbb9ea2f269ee2532078dea529eebdb8cc0a9f
[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 #ifdef CONFIG_SLIP_MODE_SLIP6
186         sl->xdata    = 0;
187         sl->xbits    = 0;
188 #endif
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         if (slcomp)
198                 slhc_free(slcomp);
199 #endif
200         kfree(xbuff);
201         kfree(rbuff);
202         return err;
203 }
204
205 /* Free a SLIP channel buffers. */
206 static void sl_free_bufs(struct slip *sl)
207 {
208         /* Free all SLIP frame buffers. */
209         kfree(xchg(&sl->rbuff, NULL));
210         kfree(xchg(&sl->xbuff, NULL));
211 #ifdef SL_INCLUDE_CSLIP
212         kfree(xchg(&sl->cbuff, NULL));
213         slhc_free(xchg(&sl->slcomp, NULL));
214 #endif
215 }
216
217 /*
218    Reallocate slip channel buffers.
219  */
220
221 static int sl_realloc_bufs(struct slip *sl, int mtu)
222 {
223         int err = 0;
224         struct net_device *dev = sl->dev;
225         unsigned char *xbuff, *rbuff;
226 #ifdef SL_INCLUDE_CSLIP
227         unsigned char *cbuff;
228 #endif
229         int len = mtu * 2;
230
231 /*
232  * allow for arrival of larger UDP packets, even if we say not to
233  * also fixes a bug in which SunOS sends 512-byte packets even with
234  * an MSS of 128
235  */
236         if (len < 576 * 2)
237                 len = 576 * 2;
238
239         xbuff = kmalloc(len + 4, GFP_ATOMIC);
240         rbuff = kmalloc(len + 4, GFP_ATOMIC);
241 #ifdef SL_INCLUDE_CSLIP
242         cbuff = kmalloc(len + 4, GFP_ATOMIC);
243 #endif
244
245
246 #ifdef SL_INCLUDE_CSLIP
247         if (xbuff == NULL || rbuff == NULL || cbuff == NULL)  {
248 #else
249         if (xbuff == NULL || rbuff == NULL)  {
250 #endif
251                 if (mtu >= sl->mtu) {
252                         printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n",
253                                dev->name);
254                         err = -ENOBUFS;
255                 }
256                 goto done;
257         }
258         spin_lock_bh(&sl->lock);
259
260         err = -ENODEV;
261         if (sl->tty == NULL)
262                 goto done_on_bh;
263
264         xbuff    = xchg(&sl->xbuff, xbuff);
265         rbuff    = xchg(&sl->rbuff, rbuff);
266 #ifdef SL_INCLUDE_CSLIP
267         cbuff    = xchg(&sl->cbuff, cbuff);
268 #endif
269         if (sl->xleft)  {
270                 if (sl->xleft <= len)  {
271                         memcpy(sl->xbuff, sl->xhead, sl->xleft);
272                 } else  {
273                         sl->xleft = 0;
274                         dev->stats.tx_dropped++;
275                 }
276         }
277         sl->xhead = sl->xbuff;
278
279         if (sl->rcount)  {
280                 if (sl->rcount <= len) {
281                         memcpy(sl->rbuff, rbuff, sl->rcount);
282                 } else  {
283                         sl->rcount = 0;
284                         dev->stats.rx_over_errors++;
285                         set_bit(SLF_ERROR, &sl->flags);
286                 }
287         }
288         sl->mtu      = mtu;
289         dev->mtu      = mtu;
290         sl->buffsize = len;
291         err = 0;
292
293 done_on_bh:
294         spin_unlock_bh(&sl->lock);
295
296 done:
297         kfree(xbuff);
298         kfree(rbuff);
299 #ifdef SL_INCLUDE_CSLIP
300         kfree(cbuff);
301 #endif
302         return err;
303 }
304
305
306 /* Set the "sending" flag.  This must be atomic hence the set_bit. */
307 static inline void sl_lock(struct slip *sl)
308 {
309         netif_stop_queue(sl->dev);
310 }
311
312
313 /* Clear the "sending" flag.  This must be atomic, hence the ASM. */
314 static inline void sl_unlock(struct slip *sl)
315 {
316         netif_wake_queue(sl->dev);
317 }
318
319 /* Send one completely decapsulated IP datagram to the IP layer. */
320 static void sl_bump(struct slip *sl)
321 {
322         struct net_device *dev = sl->dev;
323         struct sk_buff *skb;
324         int count;
325
326         count = sl->rcount;
327 #ifdef SL_INCLUDE_CSLIP
328         if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
329                 unsigned char c = sl->rbuff[0];
330                 if (c & SL_TYPE_COMPRESSED_TCP) {
331                         /* ignore compressed packets when CSLIP is off */
332                         if (!(sl->mode & SL_MODE_CSLIP)) {
333                                 printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name);
334                                 return;
335                         }
336                         /* make sure we've reserved enough space for uncompress
337                            to use */
338                         if (count + 80 > sl->buffsize) {
339                                 dev->stats.rx_over_errors++;
340                                 return;
341                         }
342                         count = slhc_uncompress(sl->slcomp, sl->rbuff, count);
343                         if (count <= 0)
344                                 return;
345                 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {
346                         if (!(sl->mode & SL_MODE_CSLIP)) {
347                                 /* turn on header compression */
348                                 sl->mode |= SL_MODE_CSLIP;
349                                 sl->mode &= ~SL_MODE_ADAPTIVE;
350                                 printk(KERN_INFO "%s: header compression turned on\n", dev->name);
351                         }
352                         sl->rbuff[0] &= 0x4f;
353                         if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0)
354                                 return;
355                 }
356         }
357 #endif  /* SL_INCLUDE_CSLIP */
358
359         dev->stats.rx_bytes += count;
360
361         skb = dev_alloc_skb(count);
362         if (skb == NULL) {
363                 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name);
364                 dev->stats.rx_dropped++;
365                 return;
366         }
367         skb->dev = dev;
368         memcpy(skb_put(skb, count), sl->rbuff, count);
369         skb_reset_mac_header(skb);
370         skb->protocol = htons(ETH_P_IP);
371         netif_rx(skb);
372         dev->stats.rx_packets++;
373 }
374
375 /* Encapsulate one IP datagram and stuff into a TTY queue. */
376 static void sl_encaps(struct slip *sl, unsigned char *icp, int len)
377 {
378         unsigned char *p;
379         int actual, count;
380
381         if (len > sl->mtu) {            /* Sigh, shouldn't occur BUT ... */
382                 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name);
383                 sl->dev->stats.tx_dropped++;
384                 sl_unlock(sl);
385                 return;
386         }
387
388         p = icp;
389 #ifdef SL_INCLUDE_CSLIP
390         if (sl->mode & SL_MODE_CSLIP)
391                 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);
392 #endif
393 #ifdef CONFIG_SLIP_MODE_SLIP6
394         if (sl->mode & SL_MODE_SLIP6)
395                 count = slip_esc6(p, (unsigned char *) sl->xbuff, len);
396         else
397 #endif
398                 count = slip_esc(p, (unsigned char *) sl->xbuff, len);
399
400         /* Order of next two lines is *very* important.
401          * When we are sending a little amount of data,
402          * the transfer may be completed inside the ops->write()
403          * routine, because it's running with interrupts enabled.
404          * In this case we *never* got WRITE_WAKEUP event,
405          * if we did not request it before write operation.
406          *       14 Oct 1994  Dmitry Gorodchanin.
407          */
408         set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
409         actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
410 #ifdef SL_CHECK_TRANSMIT
411         sl->dev->trans_start = jiffies;
412 #endif
413         sl->xleft = count - actual;
414         sl->xhead = sl->xbuff + actual;
415 #ifdef CONFIG_SLIP_SMART
416         /* VSV */
417         clear_bit(SLF_OUTWAIT, &sl->flags);     /* reset outfill flag */
418 #endif
419 }
420
421 /*
422  * Called by the driver when there's room for more data.  If we have
423  * more packets to send, we send them here.
424  */
425 static void slip_write_wakeup(struct tty_struct *tty)
426 {
427         int actual;
428         struct slip *sl = tty->disc_data;
429
430         /* First make sure we're connected. */
431         if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
432                 return;
433
434         if (sl->xleft <= 0)  {
435                 /* Now serial buffer is almost free & we can start
436                  * transmission of another packet */
437                 sl->dev->stats.tx_packets++;
438                 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
439                 sl_unlock(sl);
440                 return;
441         }
442
443         actual = tty->ops->write(tty, sl->xhead, sl->xleft);
444         sl->xleft -= actual;
445         sl->xhead += actual;
446 }
447
448 static void sl_tx_timeout(struct net_device *dev)
449 {
450         struct slip *sl = netdev_priv(dev);
451
452         spin_lock(&sl->lock);
453
454         if (netif_queue_stopped(dev)) {
455                 if (!netif_running(dev))
456                         goto out;
457
458                 /* May be we must check transmitter timeout here ?
459                  *      14 Oct 1994 Dmitry Gorodchanin.
460                  */
461 #ifdef SL_CHECK_TRANSMIT
462                 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ))  {
463                         /* 20 sec timeout not reached */
464                         goto out;
465                 }
466                 printk(KERN_WARNING "%s: transmit timed out, %s?\n",
467                         dev->name,
468                         (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
469                                 "bad line quality" : "driver error");
470                 sl->xleft = 0;
471                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
472                 sl_unlock(sl);
473 #endif
474         }
475 out:
476         spin_unlock(&sl->lock);
477 }
478
479
480 /* Encapsulate an IP datagram and kick it into a TTY queue. */
481 static netdev_tx_t
482 sl_xmit(struct sk_buff *skb, struct net_device *dev)
483 {
484         struct slip *sl = netdev_priv(dev);
485
486         spin_lock(&sl->lock);
487         if (!netif_running(dev)) {
488                 spin_unlock(&sl->lock);
489                 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
490                 dev_kfree_skb(skb);
491                 return NETDEV_TX_OK;
492         }
493         if (sl->tty == NULL) {
494                 spin_unlock(&sl->lock);
495                 dev_kfree_skb(skb);
496                 return NETDEV_TX_OK;
497         }
498
499         sl_lock(sl);
500         dev->stats.tx_bytes += skb->len;
501         sl_encaps(sl, skb->data, skb->len);
502         spin_unlock(&sl->lock);
503
504         dev_kfree_skb(skb);
505         return NETDEV_TX_OK;
506 }
507
508
509 /******************************************
510  *   Routines looking at netdevice side.
511  ******************************************/
512
513 /* Netdevice UP -> DOWN routine */
514
515 static int
516 sl_close(struct net_device *dev)
517 {
518         struct slip *sl = netdev_priv(dev);
519
520         spin_lock_bh(&sl->lock);
521         if (sl->tty)
522                 /* TTY discipline is running. */
523                 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
524         netif_stop_queue(dev);
525         sl->rcount   = 0;
526         sl->xleft    = 0;
527         spin_unlock_bh(&sl->lock);
528
529         return 0;
530 }
531
532 /* Netdevice DOWN -> UP routine */
533
534 static int sl_open(struct net_device *dev)
535 {
536         struct slip *sl = netdev_priv(dev);
537
538         if (sl->tty == NULL)
539                 return -ENODEV;
540
541         sl->flags &= (1 << SLF_INUSE);
542         netif_start_queue(dev);
543         return 0;
544 }
545
546 /* Netdevice change MTU request */
547
548 static int sl_change_mtu(struct net_device *dev, int new_mtu)
549 {
550         struct slip *sl = netdev_priv(dev);
551
552         if (new_mtu < 68 || new_mtu > 65534)
553                 return -EINVAL;
554
555         if (new_mtu != dev->mtu)
556                 return sl_realloc_bufs(sl, new_mtu);
557         return 0;
558 }
559
560 /* Netdevice get statistics request */
561
562 static struct rtnl_link_stats64 *
563 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
564 {
565         struct net_device_stats *devstats = &dev->stats;
566         unsigned long c_rx_dropped = 0;
567 #ifdef SL_INCLUDE_CSLIP
568         unsigned long c_rx_fifo_errors = 0;
569         unsigned long c_tx_fifo_errors = 0;
570         unsigned long c_collisions = 0;
571         struct slip *sl = netdev_priv(dev);
572         struct slcompress *comp = sl->slcomp;
573
574         if (comp) {
575                 c_rx_fifo_errors = comp->sls_i_compressed;
576                 c_rx_dropped     = comp->sls_i_tossed;
577                 c_tx_fifo_errors = comp->sls_o_compressed;
578                 c_collisions     = comp->sls_o_misses;
579         }
580         stats->rx_fifo_errors = sl->rx_compressed + c_rx_fifo_errors;
581         stats->tx_fifo_errors = sl->tx_compressed + c_tx_fifo_errors;
582         stats->collisions     = sl->tx_misses + c_collisions;
583 #endif
584         stats->rx_packets     = devstats->rx_packets;
585         stats->tx_packets     = devstats->tx_packets;
586         stats->rx_bytes       = devstats->rx_bytes;
587         stats->tx_bytes       = devstats->tx_bytes;
588         stats->rx_dropped     = devstats->rx_dropped + c_rx_dropped;
589         stats->tx_dropped     = devstats->tx_dropped;
590         stats->tx_errors      = devstats->tx_errors;
591         stats->rx_errors      = devstats->rx_errors;
592         stats->rx_over_errors = devstats->rx_over_errors;
593
594         return stats;
595 }
596
597 /* Netdevice register callback */
598
599 static int sl_init(struct net_device *dev)
600 {
601         struct slip *sl = netdev_priv(dev);
602
603         /*
604          *      Finish setting up the DEVICE info.
605          */
606
607         dev->mtu                = sl->mtu;
608         dev->type               = ARPHRD_SLIP + sl->mode;
609 #ifdef SL_CHECK_TRANSMIT
610         dev->watchdog_timeo     = 20*HZ;
611 #endif
612         return 0;
613 }
614
615
616 static void sl_uninit(struct net_device *dev)
617 {
618         struct slip *sl = netdev_priv(dev);
619
620         sl_free_bufs(sl);
621 }
622
623 /* Hook the destructor so we can free slip devices at the right point in time */
624 static void sl_free_netdev(struct net_device *dev)
625 {
626         int i = dev->base_addr;
627         free_netdev(dev);
628         slip_devs[i] = NULL;
629 }
630
631 static const struct net_device_ops sl_netdev_ops = {
632         .ndo_init               = sl_init,
633         .ndo_uninit             = sl_uninit,
634         .ndo_open               = sl_open,
635         .ndo_stop               = sl_close,
636         .ndo_start_xmit         = sl_xmit,
637         .ndo_get_stats64        = sl_get_stats64,
638         .ndo_change_mtu         = sl_change_mtu,
639         .ndo_tx_timeout         = sl_tx_timeout,
640 #ifdef CONFIG_SLIP_SMART
641         .ndo_do_ioctl           = sl_ioctl,
642 #endif
643 };
644
645
646 static void sl_setup(struct net_device *dev)
647 {
648         dev->netdev_ops         = &sl_netdev_ops;
649         dev->destructor         = sl_free_netdev;
650
651         dev->hard_header_len    = 0;
652         dev->addr_len           = 0;
653         dev->tx_queue_len       = 10;
654
655         /* New-style flags. */
656         dev->flags              = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
657 }
658
659 /******************************************
660   Routines looking at TTY side.
661  ******************************************/
662
663
664 /*
665  * Handle the 'receiver data ready' interrupt.
666  * This function is called by the 'tty_io' module in the kernel when
667  * a block of SLIP data has been received, which can now be decapsulated
668  * and sent on to some IP layer for further processing. This will not
669  * be re-entered while running but other ldisc functions may be called
670  * in parallel
671  */
672
673 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
674                                                         char *fp, int count)
675 {
676         struct slip *sl = tty->disc_data;
677
678         if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
679                 return;
680
681         /* Read the characters out of the buffer */
682         while (count--) {
683                 if (fp && *fp++) {
684                         if (!test_and_set_bit(SLF_ERROR, &sl->flags))
685                                 sl->dev->stats.rx_errors++;
686                         cp++;
687                         continue;
688                 }
689 #ifdef CONFIG_SLIP_MODE_SLIP6
690                 if (sl->mode & SL_MODE_SLIP6)
691                         slip_unesc6(sl, *cp++);
692                 else
693 #endif
694                         slip_unesc(sl, *cp++);
695         }
696 }
697
698 /************************************
699  *  slip_open helper routines.
700  ************************************/
701
702 /* Collect hanged up channels */
703 static void sl_sync(void)
704 {
705         int i;
706         struct net_device *dev;
707         struct slip       *sl;
708
709         for (i = 0; i < slip_maxdev; i++) {
710                 dev = slip_devs[i];
711                 if (dev == NULL)
712                         break;
713
714                 sl = netdev_priv(dev);
715                 if (sl->tty || sl->leased)
716                         continue;
717                 if (dev->flags & IFF_UP)
718                         dev_close(dev);
719         }
720 }
721
722
723 /* Find a free SLIP channel, and link in this `tty' line. */
724 static struct slip *sl_alloc(dev_t line)
725 {
726         int i;
727         struct net_device *dev = NULL;
728         struct slip       *sl;
729
730         if (slip_devs == NULL)
731                 return NULL;    /* Master array missing ! */
732
733         for (i = 0; i < slip_maxdev; i++) {
734                 dev = slip_devs[i];
735                 if (dev == NULL)
736                         break;
737         }
738         /* Sorry, too many, all slots in use */
739         if (i >= slip_maxdev)
740                 return NULL;
741
742         if (dev) {
743                 sl = netdev_priv(dev);
744                 if (test_bit(SLF_INUSE, &sl->flags)) {
745                         unregister_netdevice(dev);
746                         dev = NULL;
747                         slip_devs[i] = NULL;
748                 }
749         }
750
751         if (!dev) {
752                 char name[IFNAMSIZ];
753                 sprintf(name, "sl%d", i);
754
755                 dev = alloc_netdev(sizeof(*sl), name, sl_setup);
756                 if (!dev)
757                         return NULL;
758                 dev->base_addr  = i;
759         }
760
761         sl = netdev_priv(dev);
762
763         /* Initialize channel control data */
764         sl->magic       = SLIP_MAGIC;
765         sl->dev         = dev;
766         spin_lock_init(&sl->lock);
767         sl->mode        = SL_MODE_DEFAULT;
768 #ifdef CONFIG_SLIP_SMART
769         /* initialize timer_list struct */
770         init_timer(&sl->keepalive_timer);
771         sl->keepalive_timer.data = (unsigned long)sl;
772         sl->keepalive_timer.function = sl_keepalive;
773         init_timer(&sl->outfill_timer);
774         sl->outfill_timer.data = (unsigned long)sl;
775         sl->outfill_timer.function = sl_outfill;
776 #endif
777         slip_devs[i] = dev;
778         return sl;
779 }
780
781 /*
782  * Open the high-level part of the SLIP channel.
783  * This function is called by the TTY module when the
784  * SLIP line discipline is called for.  Because we are
785  * sure the tty line exists, we only have to link it to
786  * a free SLIP channel...
787  *
788  * Called in process context serialized from other ldisc calls.
789  */
790
791 static int slip_open(struct tty_struct *tty)
792 {
793         struct slip *sl;
794         int err;
795
796         if (!capable(CAP_NET_ADMIN))
797                 return -EPERM;
798
799         if (tty->ops->write == NULL)
800                 return -EOPNOTSUPP;
801
802         /* RTnetlink lock is misused here to serialize concurrent
803            opens of slip channels. There are better ways, but it is
804            the simplest one.
805          */
806         rtnl_lock();
807
808         /* Collect hanged up channels. */
809         sl_sync();
810
811         sl = tty->disc_data;
812
813         err = -EEXIST;
814         /* First make sure we're not already connected. */
815         if (sl && sl->magic == SLIP_MAGIC)
816                 goto err_exit;
817
818         /* OK.  Find a free SLIP channel to use. */
819         err = -ENFILE;
820         sl = sl_alloc(tty_devnum(tty));
821         if (sl == NULL)
822                 goto err_exit;
823
824         sl->tty = tty;
825         tty->disc_data = sl;
826         sl->line = tty_devnum(tty);
827         sl->pid = current->pid;
828
829         if (!test_bit(SLF_INUSE, &sl->flags)) {
830                 /* Perform the low-level SLIP initialization. */
831                 err = sl_alloc_bufs(sl, SL_MTU);
832                 if (err)
833                         goto err_free_chan;
834
835                 set_bit(SLF_INUSE, &sl->flags);
836
837                 err = register_netdevice(sl->dev);
838                 if (err)
839                         goto err_free_bufs;
840         }
841
842 #ifdef CONFIG_SLIP_SMART
843         if (sl->keepalive) {
844                 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;
845                 add_timer(&sl->keepalive_timer);
846         }
847         if (sl->outfill) {
848                 sl->outfill_timer.expires = jiffies + sl->outfill * HZ;
849                 add_timer(&sl->outfill_timer);
850         }
851 #endif
852
853         /* Done.  We have linked the TTY line to a channel. */
854         rtnl_unlock();
855         tty->receive_room = 65536;      /* We don't flow control */
856         return sl->dev->base_addr;
857
858 err_free_bufs:
859         sl_free_bufs(sl);
860
861 err_free_chan:
862         sl->tty = NULL;
863         tty->disc_data = NULL;
864         clear_bit(SLF_INUSE, &sl->flags);
865
866 err_exit:
867         rtnl_unlock();
868
869         /* Count references from TTY module */
870         return err;
871 }
872
873 /*
874  * Close down a SLIP channel.
875  * This means flushing out any pending queues, and then returning. This
876  * call is serialized against other ldisc functions.
877  *
878  * We also use this method fo a hangup event
879  */
880
881 static void slip_close(struct tty_struct *tty)
882 {
883         struct slip *sl = tty->disc_data;
884
885         /* First make sure we're connected. */
886         if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
887                 return;
888
889         tty->disc_data = NULL;
890         sl->tty = NULL;
891         if (!sl->leased)
892                 sl->line = 0;
893
894         /* VSV = very important to remove timers */
895 #ifdef CONFIG_SLIP_SMART
896         del_timer_sync(&sl->keepalive_timer);
897         del_timer_sync(&sl->outfill_timer);
898 #endif
899         /* Flush network side */
900         unregister_netdev(sl->dev);
901         /* This will complete via sl_free_netdev */
902 }
903
904 static int slip_hangup(struct tty_struct *tty)
905 {
906         slip_close(tty);
907         return 0;
908 }
909  /************************************************************************
910   *                     STANDARD SLIP ENCAPSULATION                      *
911   ************************************************************************/
912
913 static int slip_esc(unsigned char *s, unsigned char *d, int len)
914 {
915         unsigned char *ptr = d;
916         unsigned char c;
917
918         /*
919          * Send an initial END character to flush out any
920          * data that may have accumulated in the receiver
921          * due to line noise.
922          */
923
924         *ptr++ = END;
925
926         /*
927          * For each byte in the packet, send the appropriate
928          * character sequence, according to the SLIP protocol.
929          */
930
931         while (len-- > 0) {
932                 switch (c = *s++) {
933                 case END:
934                         *ptr++ = ESC;
935                         *ptr++ = ESC_END;
936                         break;
937                 case ESC:
938                         *ptr++ = ESC;
939                         *ptr++ = ESC_ESC;
940                         break;
941                 default:
942                         *ptr++ = c;
943                         break;
944                 }
945         }
946         *ptr++ = END;
947         return ptr - d;
948 }
949
950 static void slip_unesc(struct slip *sl, unsigned char s)
951 {
952
953         switch (s) {
954         case END:
955 #ifdef CONFIG_SLIP_SMART
956                 /* drop keeptest bit = VSV */
957                 if (test_bit(SLF_KEEPTEST, &sl->flags))
958                         clear_bit(SLF_KEEPTEST, &sl->flags);
959 #endif
960
961                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
962                     (sl->rcount > 2))
963                         sl_bump(sl);
964                 clear_bit(SLF_ESCAPE, &sl->flags);
965                 sl->rcount = 0;
966                 return;
967
968         case ESC:
969                 set_bit(SLF_ESCAPE, &sl->flags);
970                 return;
971         case ESC_ESC:
972                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
973                         s = ESC;
974                 break;
975         case ESC_END:
976                 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
977                         s = END;
978                 break;
979         }
980         if (!test_bit(SLF_ERROR, &sl->flags))  {
981                 if (sl->rcount < sl->buffsize)  {
982                         sl->rbuff[sl->rcount++] = s;
983                         return;
984                 }
985                 sl->dev->stats.rx_over_errors++;
986                 set_bit(SLF_ERROR, &sl->flags);
987         }
988 }
989
990
991 #ifdef CONFIG_SLIP_MODE_SLIP6
992 /************************************************************************
993  *                       6 BIT SLIP ENCAPSULATION                       *
994  ************************************************************************/
995
996 static int slip_esc6(unsigned char *s, unsigned char *d, int len)
997 {
998         unsigned char *ptr = d;
999         unsigned char c;
1000         int i;
1001         unsigned short v = 0;
1002         short bits = 0;
1003
1004         /*
1005          * Send an initial END character to flush out any
1006          * data that may have accumulated in the receiver
1007          * due to line noise.
1008          */
1009
1010         *ptr++ = 0x70;
1011
1012         /*
1013          * Encode the packet into printable ascii characters
1014          */
1015
1016         for (i = 0; i < len; ++i) {
1017                 v = (v << 8) | s[i];
1018                 bits += 8;
1019                 while (bits >= 6) {
1020                         bits -= 6;
1021                         c = 0x30 + ((v >> bits) & 0x3F);
1022                         *ptr++ = c;
1023                 }
1024         }
1025         if (bits) {
1026                 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1027                 *ptr++ = c;
1028         }
1029         *ptr++ = 0x70;
1030         return ptr - d;
1031 }
1032
1033 static void slip_unesc6(struct slip *sl, unsigned char s)
1034 {
1035         unsigned char c;
1036
1037         if (s == 0x70) {
1038 #ifdef CONFIG_SLIP_SMART
1039                 /* drop keeptest bit = VSV */
1040                 if (test_bit(SLF_KEEPTEST, &sl->flags))
1041                         clear_bit(SLF_KEEPTEST, &sl->flags);
1042 #endif
1043
1044                 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
1045                     (sl->rcount > 2))
1046                         sl_bump(sl);
1047                 sl->rcount = 0;
1048                 sl->xbits = 0;
1049                 sl->xdata = 0;
1050         } else if (s >= 0x30 && s < 0x70) {
1051                 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1052                 sl->xbits += 6;
1053                 if (sl->xbits >= 8) {
1054                         sl->xbits -= 8;
1055                         c = (unsigned char)(sl->xdata >> sl->xbits);
1056                         if (!test_bit(SLF_ERROR, &sl->flags))  {
1057                                 if (sl->rcount < sl->buffsize)  {
1058                                         sl->rbuff[sl->rcount++] = c;
1059                                         return;
1060                                 }
1061                                 sl->dev->stats.rx_over_errors++;
1062                                 set_bit(SLF_ERROR, &sl->flags);
1063                         }
1064                 }
1065         }
1066 }
1067 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1068
1069 /* Perform I/O control on an active SLIP channel. */
1070 static int slip_ioctl(struct tty_struct *tty, struct file *file,
1071                                         unsigned int cmd, unsigned long arg)
1072 {
1073         struct slip *sl = tty->disc_data;
1074         unsigned int tmp;
1075         int __user *p = (int __user *)arg;
1076
1077         /* First make sure we're connected. */
1078         if (!sl || sl->magic != SLIP_MAGIC)
1079                 return -EINVAL;
1080
1081         switch (cmd) {
1082         case SIOCGIFNAME:
1083                 tmp = strlen(sl->dev->name) + 1;
1084                 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1085                         return -EFAULT;
1086                 return 0;
1087
1088         case SIOCGIFENCAP:
1089                 if (put_user(sl->mode, p))
1090                         return -EFAULT;
1091                 return 0;
1092
1093         case SIOCSIFENCAP:
1094                 if (get_user(tmp, p))
1095                         return -EFAULT;
1096 #ifndef SL_INCLUDE_CSLIP
1097                 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
1098                         return -EINVAL;
1099 #else
1100                 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1101                     (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
1102                         /* return -EINVAL; */
1103                         tmp &= ~SL_MODE_ADAPTIVE;
1104 #endif
1105 #ifndef CONFIG_SLIP_MODE_SLIP6
1106                 if (tmp & SL_MODE_SLIP6)
1107                         return -EINVAL;
1108 #endif
1109                 sl->mode = tmp;
1110                 sl->dev->type = ARPHRD_SLIP + sl->mode;
1111                 return 0;
1112
1113         case SIOCSIFHWADDR:
1114                 return -EINVAL;
1115
1116 #ifdef CONFIG_SLIP_SMART
1117         /* VSV changes start here */
1118         case SIOCSKEEPALIVE:
1119                 if (get_user(tmp, p))
1120                         return -EFAULT;
1121                 if (tmp > 255) /* max for unchar */
1122                         return -EINVAL;
1123
1124                 spin_lock_bh(&sl->lock);
1125                 if (!sl->tty) {
1126                         spin_unlock_bh(&sl->lock);
1127                         return -ENODEV;
1128                 }
1129                 sl->keepalive = (u8)tmp;
1130                 if (sl->keepalive != 0) {
1131                         mod_timer(&sl->keepalive_timer,
1132                                         jiffies + sl->keepalive * HZ);
1133                         set_bit(SLF_KEEPTEST, &sl->flags);
1134                 } else
1135                         del_timer(&sl->keepalive_timer);
1136                 spin_unlock_bh(&sl->lock);
1137                 return 0;
1138
1139         case SIOCGKEEPALIVE:
1140                 if (put_user(sl->keepalive, p))
1141                         return -EFAULT;
1142                 return 0;
1143
1144         case SIOCSOUTFILL:
1145                 if (get_user(tmp, p))
1146                         return -EFAULT;
1147                 if (tmp > 255) /* max for unchar */
1148                         return -EINVAL;
1149                 spin_lock_bh(&sl->lock);
1150                 if (!sl->tty) {
1151                         spin_unlock_bh(&sl->lock);
1152                         return -ENODEV;
1153                 }
1154                 sl->outfill = (u8)tmp;
1155                 if (sl->outfill != 0) {
1156                         mod_timer(&sl->outfill_timer,
1157                                                 jiffies + sl->outfill * HZ);
1158                         set_bit(SLF_OUTWAIT, &sl->flags);
1159                 } else
1160                         del_timer(&sl->outfill_timer);
1161                 spin_unlock_bh(&sl->lock);
1162                 return 0;
1163
1164         case SIOCGOUTFILL:
1165                 if (put_user(sl->outfill, p))
1166                         return -EFAULT;
1167                 return 0;
1168         /* VSV changes end */
1169 #endif
1170         default:
1171                 return tty_mode_ioctl(tty, file, cmd, arg);
1172         }
1173 }
1174
1175 #ifdef CONFIG_COMPAT
1176 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
1177                                         unsigned int cmd, unsigned long arg)
1178 {
1179         switch (cmd) {
1180         case SIOCGIFNAME:
1181         case SIOCGIFENCAP:
1182         case SIOCSIFENCAP:
1183         case SIOCSIFHWADDR:
1184         case SIOCSKEEPALIVE:
1185         case SIOCGKEEPALIVE:
1186         case SIOCSOUTFILL:
1187         case SIOCGOUTFILL:
1188                 return slip_ioctl(tty, file, cmd,
1189                                   (unsigned long)compat_ptr(arg));
1190         }
1191
1192         return -ENOIOCTLCMD;
1193 }
1194 #endif
1195
1196 /* VSV changes start here */
1197 #ifdef CONFIG_SLIP_SMART
1198 /* function do_ioctl called from net/core/dev.c
1199    to allow get/set outfill/keepalive parameter
1200    by ifconfig                                 */
1201
1202 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
1203 {
1204         struct slip *sl = netdev_priv(dev);
1205         unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1206
1207         if (sl == NULL)         /* Allocation failed ?? */
1208                 return -ENODEV;
1209
1210         spin_lock_bh(&sl->lock);
1211
1212         if (!sl->tty) {
1213                 spin_unlock_bh(&sl->lock);
1214                 return -ENODEV;
1215         }
1216
1217         switch (cmd) {
1218         case SIOCSKEEPALIVE:
1219                 /* max for unchar */
1220                 if ((unsigned)*p > 255) {
1221                         spin_unlock_bh(&sl->lock);
1222                         return -EINVAL;
1223                 }
1224                 sl->keepalive = (u8)*p;
1225                 if (sl->keepalive != 0) {
1226                         sl->keepalive_timer.expires =
1227                                                 jiffies + sl->keepalive * HZ;
1228                         mod_timer(&sl->keepalive_timer,
1229                                                 jiffies + sl->keepalive * HZ);
1230                         set_bit(SLF_KEEPTEST, &sl->flags);
1231                 } else
1232                         del_timer(&sl->keepalive_timer);
1233                 break;
1234
1235         case SIOCGKEEPALIVE:
1236                 *p = sl->keepalive;
1237                 break;
1238
1239         case SIOCSOUTFILL:
1240                 if ((unsigned)*p > 255) { /* max for unchar */
1241                         spin_unlock_bh(&sl->lock);
1242                         return -EINVAL;
1243                 }
1244                 sl->outfill = (u8)*p;
1245                 if (sl->outfill != 0) {
1246                         mod_timer(&sl->outfill_timer,
1247                                                 jiffies + sl->outfill * HZ);
1248                         set_bit(SLF_OUTWAIT, &sl->flags);
1249                 } else
1250                         del_timer(&sl->outfill_timer);
1251                 break;
1252
1253         case SIOCGOUTFILL:
1254                 *p = sl->outfill;
1255                 break;
1256
1257         case SIOCSLEASE:
1258                 /* Resolve race condition, when ioctl'ing hanged up
1259                    and opened by another process device.
1260                  */
1261                 if (sl->tty != current->signal->tty &&
1262                                                 sl->pid != current->pid) {
1263                         spin_unlock_bh(&sl->lock);
1264                         return -EPERM;
1265                 }
1266                 sl->leased = 0;
1267                 if (*p)
1268                         sl->leased = 1;
1269                 break;
1270
1271         case SIOCGLEASE:
1272                 *p = sl->leased;
1273         }
1274         spin_unlock_bh(&sl->lock);
1275         return 0;
1276 }
1277 #endif
1278 /* VSV changes end */
1279
1280 static struct tty_ldisc_ops sl_ldisc = {
1281         .owner          = THIS_MODULE,
1282         .magic          = TTY_LDISC_MAGIC,
1283         .name           = "slip",
1284         .open           = slip_open,
1285         .close          = slip_close,
1286         .hangup         = slip_hangup,
1287         .ioctl          = slip_ioctl,
1288 #ifdef CONFIG_COMPAT
1289         .compat_ioctl   = slip_compat_ioctl,
1290 #endif
1291         .receive_buf    = slip_receive_buf,
1292         .write_wakeup   = slip_write_wakeup,
1293 };
1294
1295 static int __init slip_init(void)
1296 {
1297         int status;
1298
1299         if (slip_maxdev < 4)
1300                 slip_maxdev = 4; /* Sanity */
1301
1302         printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1303 #ifdef CONFIG_SLIP_MODE_SLIP6
1304                " (6 bit encapsulation enabled)"
1305 #endif
1306                ".\n",
1307                SLIP_VERSION, slip_maxdev);
1308 #if defined(SL_INCLUDE_CSLIP)
1309         printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1310 #endif
1311 #ifdef CONFIG_SLIP_SMART
1312         printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1313 #endif
1314
1315         slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev,
1316                                                                 GFP_KERNEL);
1317         if (!slip_devs) {
1318                 printk(KERN_ERR "SLIP: Can't allocate slip devices array.\n");
1319                 return -ENOMEM;
1320         }
1321
1322         /* Fill in our line protocol discipline, and register it */
1323         status = tty_register_ldisc(N_SLIP, &sl_ldisc);
1324         if (status != 0) {
1325                 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1326                 kfree(slip_devs);
1327         }
1328         return status;
1329 }
1330
1331 static void __exit slip_exit(void)
1332 {
1333         int i;
1334         struct net_device *dev;
1335         struct slip *sl;
1336         unsigned long timeout = jiffies + HZ;
1337         int busy = 0;
1338
1339         if (slip_devs == NULL)
1340                 return;
1341
1342         /* First of all: check for active disciplines and hangup them.
1343          */
1344         do {
1345                 if (busy)
1346                         msleep_interruptible(100);
1347
1348                 busy = 0;
1349                 for (i = 0; i < slip_maxdev; i++) {
1350                         dev = slip_devs[i];
1351                         if (!dev)
1352                                 continue;
1353                         sl = netdev_priv(dev);
1354                         spin_lock_bh(&sl->lock);
1355                         if (sl->tty) {
1356                                 busy++;
1357                                 tty_hangup(sl->tty);
1358                         }
1359                         spin_unlock_bh(&sl->lock);
1360                 }
1361         } while (busy && time_before(jiffies, timeout));
1362
1363         /* FIXME: hangup is async so we should wait when doing this second
1364            phase */
1365
1366         for (i = 0; i < slip_maxdev; i++) {
1367                 dev = slip_devs[i];
1368                 if (!dev)
1369                         continue;
1370                 slip_devs[i] = NULL;
1371
1372                 sl = netdev_priv(dev);
1373                 if (sl->tty) {
1374                         printk(KERN_ERR "%s: tty discipline still running\n",
1375                                dev->name);
1376                         /* Intentionally leak the control block. */
1377                         dev->destructor = NULL;
1378                 }
1379
1380                 unregister_netdev(dev);
1381         }
1382
1383         kfree(slip_devs);
1384         slip_devs = NULL;
1385
1386         i = tty_unregister_ldisc(N_SLIP);
1387         if (i != 0)
1388                 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1389 }
1390
1391 module_init(slip_init);
1392 module_exit(slip_exit);
1393
1394 #ifdef CONFIG_SLIP_SMART
1395 /*
1396  * This is start of the code for multislip style line checking
1397  * added by Stanislav Voronyi. All changes before marked VSV
1398  */
1399
1400 static void sl_outfill(unsigned long sls)
1401 {
1402         struct slip *sl = (struct slip *)sls;
1403
1404         spin_lock(&sl->lock);
1405
1406         if (sl->tty == NULL)
1407                 goto out;
1408
1409         if (sl->outfill) {
1410                 if (test_bit(SLF_OUTWAIT, &sl->flags)) {
1411                         /* no packets were transmitted, do outfill */
1412 #ifdef CONFIG_SLIP_MODE_SLIP6
1413                         unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1414 #else
1415                         unsigned char s = END;
1416 #endif
1417                         /* put END into tty queue. Is it right ??? */
1418                         if (!netif_queue_stopped(sl->dev)) {
1419                                 /* if device busy no outfill */
1420                                 sl->tty->ops->write(sl->tty, &s, 1);
1421                         }
1422                 } else
1423                         set_bit(SLF_OUTWAIT, &sl->flags);
1424
1425                 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1426         }
1427 out:
1428         spin_unlock(&sl->lock);
1429 }
1430
1431 static void sl_keepalive(unsigned long sls)
1432 {
1433         struct slip *sl = (struct slip *)sls;
1434
1435         spin_lock(&sl->lock);
1436
1437         if (sl->tty == NULL)
1438                 goto out;
1439
1440         if (sl->keepalive) {
1441                 if (test_bit(SLF_KEEPTEST, &sl->flags)) {
1442                         /* keepalive still high :(, we must hangup */
1443                         if (sl->outfill)
1444                                 /* outfill timer must be deleted too */
1445                                 (void)del_timer(&sl->outfill_timer);
1446                         printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1447                         /* this must hangup tty & close slip */
1448                         tty_hangup(sl->tty);
1449                         /* I think we need not something else */
1450                         goto out;
1451                 } else
1452                         set_bit(SLF_KEEPTEST, &sl->flags);
1453
1454                 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1455         }
1456 out:
1457         spin_unlock(&sl->lock);
1458 }
1459
1460 #endif
1461 MODULE_LICENSE("GPL");
1462 MODULE_ALIAS_LDISC(N_SLIP);