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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
96static struct net_device **slip_devs;
97
98static int slip_maxdev = SL_NRUNIT;
99module_param(slip_maxdev, int, 0);
100MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
101
102static int slip_esc(unsigned char *p, unsigned char *d, int len);
103static void slip_unesc(struct slip *sl, unsigned char c);
104#ifdef CONFIG_SLIP_MODE_SLIP6
105static int slip_esc6(unsigned char *p, unsigned char *d, int len);
106static void slip_unesc6(struct slip *sl, unsigned char c);
107#endif
108#ifdef CONFIG_SLIP_SMART
109static void sl_keepalive(unsigned long sls);
110static void sl_outfill(unsigned long sls);
111static 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
129static 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 */
194err_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. */
205static 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
220static 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
292done_on_bh:
293 spin_unlock_bh(&sl->lock);
294
295done:
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. */
306static 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. */
313static 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. */
319static 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. */
375static 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 */
424static 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
447static 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 }
474out:
475 spin_unlock(&sl->lock);
476}
477
478
479/* Encapsulate an IP datagram and kick it into a TTY queue. */
480static netdev_tx_t
481sl_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
514static int
515sl_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
533static 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
547static 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
561static struct rtnl_link_stats64 *
562sl_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
598static 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
615static 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 */
623static 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
630static 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
645static 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
672static 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 */
702static 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. */
723static 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
775static 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
843err_free_bufs:
844 sl_free_bufs(sl);
845
846err_free_chan:
847 sl->tty = NULL;
848 tty->disc_data = NULL;
849 clear_bit(SLF_INUSE, &sl->flags);
850
851err_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
866static 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
887static int slip_hangup(struct tty_struct *tty)
888{
889 slip_close(tty);
890 return 0;
891}
892 /************************************************************************
893 * STANDARD SLIP ENCAPSULATION *
894 ************************************************************************/
895
896static 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
933static 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
979static 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
1016static 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. */
1053static 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
1159static 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
1185static 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
1263static 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
1278static 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
1314static 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
1374module_init(slip_init);
1375module_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
1383static 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 }
1410out:
1411 spin_unlock(&sl->lock);
1412}
1413
1414static 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 }
1439out:
1440 spin_unlock(&sl->lock);
1441}
1442
1443#endif
1444MODULE_LICENSE("GPL");
1445MODULE_ALIAS_LDISC(N_SLIP);