1 /*
2 * slip.c This module implements the SLIP protocol for kernel-based
3 * devices like TTY. It interfaces between a raw TTY, and the
4 * kernel's INET protocol layers.
5 *
6 * Version: @(#)slip.c 0.8.3 12/24/94
7 *
8 * Authors: Laurence Culhane, <loz@holmes.demon.co.uk>
9 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
10 *
11 * Fixes:
12 * Alan Cox : Sanity checks and avoid tx overruns.
13 * Has a new sl->mtu field.
14 * Alan Cox : Found cause of overrun. ifconfig sl0
15 * mtu upwards. Driver now spots this
16 * and grows/shrinks its buffers(hack!).
17 * Memory leak if you run out of memory
18 * setting up a slip driver fixed.
19 * Matt Dillon : Printable slip (borrowed from NET2E)
20 * Pauline Middelink : Slip driver fixes.
21 * Alan Cox : Honours the old SL_COMPRESSED flag
22 * Alan Cox : KISS AX.25 and AXUI IP support
23 * Michael Riepe : Automatic CSLIP recognition added
24 * Charles Hedrick : CSLIP header length problem fix.
25 * Alan Cox : Corrected non-IP cases of the above.
26 * Alan Cox : Now uses hardware type as per FvK.
27 * Alan Cox : Default to 192.168.0.0 (RFC 1597)
28 * A.N.Kuznetsov : dev_tint() recursion fix.
29 * Dmitry Gorodchanin : SLIP memory leaks
30 * Dmitry Gorodchanin : Code cleanup. Reduce tty driver
31 * buffering from 4096 to 256 bytes.
32 * Improving SLIP response time.
33 * CONFIG_SLIP_MODE_SLIP6.
34 * ifconfig sl? up & down now works
35 * correctly.
36 * Modularization.
37 * Alan Cox : Oops - fix AX.25 buffer lengths
38 * Dmitry Gorodchanin : Even more cleanups. Preserve CSLIP
39 * statistics. Include CSLIP code only
40 * if it really needed.
41 * Alan Cox : Free slhc buffers in the right place.
42 * Alan Cox : Allow for digipeated IP over AX.25
43 * Matti Aarnio : Dynamic SLIP devices, with ideas taken
44 * from Jim Freeman's <jfree@caldera.com>
45 * dynamic PPP devices. We do NOT kfree()
46 * device entries, just reg./unreg. them
47 * as they are needed. We kfree() them
48 * at module cleanup.
49 * With MODULE-loading ``insmod'', user
50 * can issue parameter: slip_maxdev=1024
51 * (Or how much he/she wants.. Default
52 * is 256)
53 * Stanislav Voronyi : Slip line checking, with ideas taken
54 * from multislip BSDI driver which was
55 * written by Igor Chechik, RELCOM Corp.
56 * Only algorithms have been ported to
57 * Linux SLIP driver.
58 * Vitaly E. Lavrov : Sane behaviour on tty hangup.
59 * Alexey Kuznetsov : Cleanup interfaces to tty & netdevice
60 * modules.
61 */
62
63 #define SL_CHECK_TRANSMIT
64 #include <linux/module.h>
65 #include <linux/moduleparam.h>
66
67 #include <asm/uaccess.h>
68 #include <linux/bitops.h>
69 #include <linux/sched.h>
70 #include <linux/string.h>
71 #include <linux/mm.h>
72 #include <linux/interrupt.h>
73 #include <linux/in.h>
74 #include <linux/tty.h>
75 #include <linux/errno.h>
76 #include <linux/netdevice.h>
77 #include <linux/etherdevice.h>
78 #include <linux/skbuff.h>
79 #include <linux/rtnetlink.h>
80 #include <linux/if_arp.h>
81 #include <linux/if_slip.h>
82 #include <linux/compat.h>
83 #include <linux/delay.h>
84 #include <linux/init.h>
85 #include <linux/slab.h>
86 #include "slip.h"
87 #ifdef CONFIG_INET
88 #include <linux/ip.h>
89 #include <linux/tcp.h>
90 #include <net/slhc_vj.h>
91 #endif
92
93 #define SLIP_VERSION "0.8.4-NET3.019-NEWTTY"
94
95 static struct net_device **slip_devs;
96
97 static int slip_maxdev = SL_NRUNIT;
98 module_param(slip_maxdev, int, 0);
99 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
100
101 static int slip_esc(unsigned char *p, unsigned char *d, int len);
102 static void slip_unesc(struct slip *sl, unsigned char c);
103 #ifdef CONFIG_SLIP_MODE_SLIP6
104 static int slip_esc6(unsigned char *p, unsigned char *d, int len);
105 static void slip_unesc6(struct slip *sl, unsigned char c);
106 #endif
107 #ifdef CONFIG_SLIP_SMART
108 static void sl_keepalive(unsigned long sls);
109 static void sl_outfill(unsigned long sls);
110 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
111 #endif
112
113 /********************************
114 * Buffer administration routines:
115 * sl_alloc_bufs()
116 * sl_free_bufs()
117 * sl_realloc_bufs()
118 *
119 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because
120 * sl_realloc_bufs provides strong atomicity and reallocation
121 * on actively running device.
122 *********************************/
123
124 /*
125 Allocate channel buffers.
126 */
127
sl_alloc_bufs(struct slip * sl,int mtu)128 static int sl_alloc_bufs(struct slip *sl, int mtu)
129 {
130 int err = -ENOBUFS;
131 unsigned long len;
132 char *rbuff = NULL;
133 char *xbuff = NULL;
134 #ifdef SL_INCLUDE_CSLIP
135 char *cbuff = NULL;
136 struct slcompress *slcomp = NULL;
137 #endif
138
139 /*
140 * Allocate the SLIP frame buffers:
141 *
142 * rbuff Receive buffer.
143 * xbuff Transmit buffer.
144 * cbuff Temporary compression buffer.
145 */
146 len = mtu * 2;
147
148 /*
149 * allow for arrival of larger UDP packets, even if we say not to
150 * also fixes a bug in which SunOS sends 512-byte packets even with
151 * an MSS of 128
152 */
153 if (len < 576 * 2)
154 len = 576 * 2;
155 rbuff = kmalloc(len + 4, GFP_KERNEL);
156 if (rbuff == NULL)
157 goto err_exit;
158 xbuff = kmalloc(len + 4, GFP_KERNEL);
159 if (xbuff == NULL)
160 goto err_exit;
161 #ifdef SL_INCLUDE_CSLIP
162 cbuff = kmalloc(len + 4, GFP_KERNEL);
163 if (cbuff == NULL)
164 goto err_exit;
165 slcomp = slhc_init(16, 16);
166 if (slcomp == NULL)
167 goto err_exit;
168 #endif
169 spin_lock_bh(&sl->lock);
170 if (sl->tty == NULL) {
171 spin_unlock_bh(&sl->lock);
172 err = -ENODEV;
173 goto err_exit;
174 }
175 sl->mtu = mtu;
176 sl->buffsize = len;
177 sl->rcount = 0;
178 sl->xleft = 0;
179 rbuff = xchg(&sl->rbuff, rbuff);
180 xbuff = xchg(&sl->xbuff, xbuff);
181 #ifdef SL_INCLUDE_CSLIP
182 cbuff = xchg(&sl->cbuff, cbuff);
183 slcomp = xchg(&sl->slcomp, slcomp);
184 #endif
185 #ifdef CONFIG_SLIP_MODE_SLIP6
186 sl->xdata = 0;
187 sl->xbits = 0;
188 #endif
189 spin_unlock_bh(&sl->lock);
190 err = 0;
191
192 /* Cleanup */
193 err_exit:
194 #ifdef SL_INCLUDE_CSLIP
195 kfree(cbuff);
196 slhc_free(slcomp);
197 #endif
198 kfree(xbuff);
199 kfree(rbuff);
200 return err;
201 }
202
203 /* Free a SLIP channel buffers. */
sl_free_bufs(struct slip * sl)204 static void sl_free_bufs(struct slip *sl)
205 {
206 /* Free all SLIP frame buffers. */
207 kfree(xchg(&sl->rbuff, NULL));
208 kfree(xchg(&sl->xbuff, NULL));
209 #ifdef SL_INCLUDE_CSLIP
210 kfree(xchg(&sl->cbuff, NULL));
211 slhc_free(xchg(&sl->slcomp, NULL));
212 #endif
213 }
214
215 /*
216 Reallocate slip channel buffers.
217 */
218
sl_realloc_bufs(struct slip * sl,int mtu)219 static int sl_realloc_bufs(struct slip *sl, int mtu)
220 {
221 int err = 0;
222 struct net_device *dev = sl->dev;
223 unsigned char *xbuff, *rbuff;
224 #ifdef SL_INCLUDE_CSLIP
225 unsigned char *cbuff;
226 #endif
227 int len = mtu * 2;
228
229 /*
230 * allow for arrival of larger UDP packets, even if we say not to
231 * also fixes a bug in which SunOS sends 512-byte packets even with
232 * an MSS of 128
233 */
234 if (len < 576 * 2)
235 len = 576 * 2;
236
237 xbuff = kmalloc(len + 4, GFP_ATOMIC);
238 rbuff = kmalloc(len + 4, GFP_ATOMIC);
239 #ifdef SL_INCLUDE_CSLIP
240 cbuff = kmalloc(len + 4, GFP_ATOMIC);
241 #endif
242
243
244 #ifdef SL_INCLUDE_CSLIP
245 if (xbuff == NULL || rbuff == NULL || cbuff == NULL) {
246 #else
247 if (xbuff == NULL || rbuff == NULL) {
248 #endif
249 if (mtu > sl->mtu) {
250 printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n",
251 dev->name);
252 err = -ENOBUFS;
253 }
254 goto done;
255 }
256 spin_lock_bh(&sl->lock);
257
258 err = -ENODEV;
259 if (sl->tty == NULL)
260 goto done_on_bh;
261
262 xbuff = xchg(&sl->xbuff, xbuff);
263 rbuff = xchg(&sl->rbuff, rbuff);
264 #ifdef SL_INCLUDE_CSLIP
265 cbuff = xchg(&sl->cbuff, cbuff);
266 #endif
267 if (sl->xleft) {
268 if (sl->xleft <= len) {
269 memcpy(sl->xbuff, sl->xhead, sl->xleft);
270 } else {
271 sl->xleft = 0;
272 dev->stats.tx_dropped++;
273 }
274 }
275 sl->xhead = sl->xbuff;
276
277 if (sl->rcount) {
278 if (sl->rcount <= len) {
279 memcpy(sl->rbuff, rbuff, sl->rcount);
280 } else {
281 sl->rcount = 0;
282 dev->stats.rx_over_errors++;
283 set_bit(SLF_ERROR, &sl->flags);
284 }
285 }
286 sl->mtu = mtu;
287 dev->mtu = mtu;
288 sl->buffsize = len;
289 err = 0;
290
291 done_on_bh:
292 spin_unlock_bh(&sl->lock);
293
294 done:
295 kfree(xbuff);
296 kfree(rbuff);
297 #ifdef SL_INCLUDE_CSLIP
298 kfree(cbuff);
299 #endif
300 return err;
301 }
302
303
304 /* Set the "sending" flag. This must be atomic hence the set_bit. */
305 static inline void sl_lock(struct slip *sl)
306 {
307 netif_stop_queue(sl->dev);
308 }
309
310
311 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
312 static inline void sl_unlock(struct slip *sl)
313 {
314 netif_wake_queue(sl->dev);
315 }
316
317 /* Send one completely decapsulated IP datagram to the IP layer. */
318 static void sl_bump(struct slip *sl)
319 {
320 struct net_device *dev = sl->dev;
321 struct sk_buff *skb;
322 int count;
323
324 count = sl->rcount;
325 #ifdef SL_INCLUDE_CSLIP
326 if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {
327 unsigned char c = sl->rbuff[0];
328 if (c & SL_TYPE_COMPRESSED_TCP) {
329 /* ignore compressed packets when CSLIP is off */
330 if (!(sl->mode & SL_MODE_CSLIP)) {
331 printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name);
332 return;
333 }
334 /* make sure we've reserved enough space for uncompress
335 to use */
336 if (count + 80 > sl->buffsize) {
337 dev->stats.rx_over_errors++;
338 return;
339 }
340 count = slhc_uncompress(sl->slcomp, sl->rbuff, count);
341 if (count <= 0)
342 return;
343 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {
344 if (!(sl->mode & SL_MODE_CSLIP)) {
345 /* turn on header compression */
346 sl->mode |= SL_MODE_CSLIP;
347 sl->mode &= ~SL_MODE_ADAPTIVE;
348 printk(KERN_INFO "%s: header compression turned on\n", dev->name);
349 }
350 sl->rbuff[0] &= 0x4f;
351 if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0)
352 return;
353 }
354 }
355 #endif /* SL_INCLUDE_CSLIP */
356
357 dev->stats.rx_bytes += count;
358
359 skb = dev_alloc_skb(count);
360 if (skb == NULL) {
361 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name);
362 dev->stats.rx_dropped++;
363 return;
364 }
365 skb->dev = dev;
366 memcpy(skb_put(skb, count), sl->rbuff, count);
367 skb_reset_mac_header(skb);
368 skb->protocol = htons(ETH_P_IP);
369 netif_rx_ni(skb);
370 dev->stats.rx_packets++;
371 }
372
373 /* Encapsulate one IP datagram and stuff into a TTY queue. */
374 static void sl_encaps(struct slip *sl, unsigned char *icp, int len)
375 {
376 unsigned char *p;
377 int actual, count;
378
379 if (len > sl->mtu) { /* Sigh, shouldn't occur BUT ... */
380 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name);
381 sl->dev->stats.tx_dropped++;
382 sl_unlock(sl);
383 return;
384 }
385
386 p = icp;
387 #ifdef SL_INCLUDE_CSLIP
388 if (sl->mode & SL_MODE_CSLIP)
389 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);
390 #endif
391 #ifdef CONFIG_SLIP_MODE_SLIP6
392 if (sl->mode & SL_MODE_SLIP6)
393 count = slip_esc6(p, (unsigned char *) sl->xbuff, len);
394 else
395 #endif
396 count = slip_esc(p, (unsigned char *) sl->xbuff, len);
397
398 /* Order of next two lines is *very* important.
399 * When we are sending a little amount of data,
400 * the transfer may be completed inside the ops->write()
401 * routine, because it's running with interrupts enabled.
402 * In this case we *never* got WRITE_WAKEUP event,
403 * if we did not request it before write operation.
404 * 14 Oct 1994 Dmitry Gorodchanin.
405 */
406 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
407 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
408 #ifdef SL_CHECK_TRANSMIT
409 sl->dev->trans_start = jiffies;
410 #endif
411 sl->xleft = count - actual;
412 sl->xhead = sl->xbuff + actual;
413 #ifdef CONFIG_SLIP_SMART
414 /* VSV */
415 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
416 #endif
417 }
418
419 /*
420 * Called by the driver when there's room for more data. If we have
421 * more packets to send, we send them here.
422 */
423 static void slip_write_wakeup(struct tty_struct *tty)
424 {
425 int actual;
426 struct slip *sl = tty->disc_data;
427
428 /* First make sure we're connected. */
429 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
430 return;
431
432 if (sl->xleft <= 0) {
433 /* Now serial buffer is almost free & we can start
434 * transmission of another packet */
435 sl->dev->stats.tx_packets++;
436 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
437 sl_unlock(sl);
438 return;
439 }
440
441 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
442 sl->xleft -= actual;
443 sl->xhead += actual;
444 }
445
446 static void sl_tx_timeout(struct net_device *dev)
447 {
448 struct slip *sl = netdev_priv(dev);
449
450 spin_lock(&sl->lock);
451
452 if (netif_queue_stopped(dev)) {
453 if (!netif_running(dev))
454 goto out;
455
456 /* May be we must check transmitter timeout here ?
457 * 14 Oct 1994 Dmitry Gorodchanin.
458 */
459 #ifdef SL_CHECK_TRANSMIT
460 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) {
461 /* 20 sec timeout not reached */
462 goto out;
463 }
464 printk(KERN_WARNING "%s: transmit timed out, %s?\n",
465 dev->name,
466 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
467 "bad line quality" : "driver error");
468 sl->xleft = 0;
469 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
470 sl_unlock(sl);
471 #endif
472 }
473 out:
474 spin_unlock(&sl->lock);
475 }
476
477
478 /* Encapsulate an IP datagram and kick it into a TTY queue. */
479 static netdev_tx_t
480 sl_xmit(struct sk_buff *skb, struct net_device *dev)
481 {
482 struct slip *sl = netdev_priv(dev);
483
484 spin_lock(&sl->lock);
485 if (!netif_running(dev)) {
486 spin_unlock(&sl->lock);
487 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
488 dev_kfree_skb(skb);
489 return NETDEV_TX_OK;
490 }
491 if (sl->tty == NULL) {
492 spin_unlock(&sl->lock);
493 dev_kfree_skb(skb);
494 return NETDEV_TX_OK;
495 }
496
497 sl_lock(sl);
498 dev->stats.tx_bytes += skb->len;
499 sl_encaps(sl, skb->data, skb->len);
500 spin_unlock(&sl->lock);
501
502 dev_kfree_skb(skb);
503 return NETDEV_TX_OK;
504 }
505
506
507 /******************************************
508 * Routines looking at netdevice side.
509 ******************************************/
510
511 /* Netdevice UP -> DOWN routine */
512
513 static int
514 sl_close(struct net_device *dev)
515 {
516 struct slip *sl = netdev_priv(dev);
517
518 spin_lock_bh(&sl->lock);
519 if (sl->tty)
520 /* TTY discipline is running. */
521 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
522 netif_stop_queue(dev);
523 sl->rcount = 0;
524 sl->xleft = 0;
525 spin_unlock_bh(&sl->lock);
526
527 return 0;
528 }
529
530 /* Netdevice DOWN -> UP routine */
531
532 static int sl_open(struct net_device *dev)
533 {
534 struct slip *sl = netdev_priv(dev);
535
536 if (sl->tty == NULL)
537 return -ENODEV;
538
539 sl->flags &= (1 << SLF_INUSE);
540 netif_start_queue(dev);
541 return 0;
542 }
543
544 /* Netdevice change MTU request */
545
546 static int sl_change_mtu(struct net_device *dev, int new_mtu)
547 {
548 struct slip *sl = netdev_priv(dev);
549
550 if (new_mtu < 68 || new_mtu > 65534)
551 return -EINVAL;
552
553 if (new_mtu != dev->mtu)
554 return sl_realloc_bufs(sl, new_mtu);
555 return 0;
556 }
557
558 /* Netdevice get statistics request */
559
560 static struct rtnl_link_stats64 *
561 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
562 {
563 struct net_device_stats *devstats = &dev->stats;
564 #ifdef SL_INCLUDE_CSLIP
565 struct slip *sl = netdev_priv(dev);
566 struct slcompress *comp = sl->slcomp;
567 #endif
568 stats->rx_packets = devstats->rx_packets;
569 stats->tx_packets = devstats->tx_packets;
570 stats->rx_bytes = devstats->rx_bytes;
571 stats->tx_bytes = devstats->tx_bytes;
572 stats->rx_dropped = devstats->rx_dropped;
573 stats->tx_dropped = devstats->tx_dropped;
574 stats->tx_errors = devstats->tx_errors;
575 stats->rx_errors = devstats->rx_errors;
576 stats->rx_over_errors = devstats->rx_over_errors;
577
578 #ifdef SL_INCLUDE_CSLIP
579 if (comp) {
580 /* Generic compressed statistics */
581 stats->rx_compressed = comp->sls_i_compressed;
582 stats->tx_compressed = comp->sls_o_compressed;
583
584 /* Are we really still needs this? */
585 stats->rx_fifo_errors += comp->sls_i_compressed;
586 stats->rx_dropped += comp->sls_i_tossed;
587 stats->tx_fifo_errors += comp->sls_o_compressed;
588 stats->collisions += comp->sls_o_misses;
589 }
590 #endif
591 return stats;
592 }
593
594 /* Netdevice register callback */
595
596 static int sl_init(struct net_device *dev)
597 {
598 struct slip *sl = netdev_priv(dev);
599
600 /*
601 * Finish setting up the DEVICE info.
602 */
603
604 dev->mtu = sl->mtu;
605 dev->type = ARPHRD_SLIP + sl->mode;
606 #ifdef SL_CHECK_TRANSMIT
607 dev->watchdog_timeo = 20*HZ;
608 #endif
609 return 0;
610 }
611
612
613 static void sl_uninit(struct net_device *dev)
614 {
615 struct slip *sl = netdev_priv(dev);
616
617 sl_free_bufs(sl);
618 }
619
620 /* Hook the destructor so we can free slip devices at the right point in time */
621 static void sl_free_netdev(struct net_device *dev)
622 {
623 int i = dev->base_addr;
624 free_netdev(dev);
625 slip_devs[i] = NULL;
626 }
627
628 static const struct net_device_ops sl_netdev_ops = {
629 .ndo_init = sl_init,
630 .ndo_uninit = sl_uninit,
631 .ndo_open = sl_open,
632 .ndo_stop = sl_close,
633 .ndo_start_xmit = sl_xmit,
634 .ndo_get_stats64 = sl_get_stats64,
635 .ndo_change_mtu = sl_change_mtu,
636 .ndo_tx_timeout = sl_tx_timeout,
637 #ifdef CONFIG_SLIP_SMART
638 .ndo_do_ioctl = sl_ioctl,
639 #endif
640 };
641
642
643 static void sl_setup(struct net_device *dev)
644 {
645 dev->netdev_ops = &sl_netdev_ops;
646 dev->destructor = sl_free_netdev;
647
648 dev->hard_header_len = 0;
649 dev->addr_len = 0;
650 dev->tx_queue_len = 10;
651
652 /* New-style flags. */
653 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
654 }
655
656 /******************************************
657 Routines looking at TTY side.
658 ******************************************/
659
660
661 /*
662 * Handle the 'receiver data ready' interrupt.
663 * This function is called by the 'tty_io' module in the kernel when
664 * a block of SLIP data has been received, which can now be decapsulated
665 * and sent on to some IP layer for further processing. This will not
666 * be re-entered while running but other ldisc functions may be called
667 * in parallel
668 */
669
670 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp,
671 char *fp, int count)
672 {
673 struct slip *sl = tty->disc_data;
674
675 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
676 return;
677
678 /* Read the characters out of the buffer */
679 while (count--) {
680 if (fp && *fp++) {
681 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
682 sl->dev->stats.rx_errors++;
683 cp++;
684 continue;
685 }
686 #ifdef CONFIG_SLIP_MODE_SLIP6
687 if (sl->mode & SL_MODE_SLIP6)
688 slip_unesc6(sl, *cp++);
689 else
690 #endif
691 slip_unesc(sl, *cp++);
692 }
693 }
694
695 /************************************
696 * slip_open helper routines.
697 ************************************/
698
699 /* Collect hanged up channels */
700 static void sl_sync(void)
701 {
702 int i;
703 struct net_device *dev;
704 struct slip *sl;
705
706 for (i = 0; i < slip_maxdev; i++) {
707 dev = slip_devs[i];
708 if (dev == NULL)
709 break;
710
711 sl = netdev_priv(dev);
712 if (sl->tty || sl->leased)
713 continue;
714 if (dev->flags & IFF_UP)
715 dev_close(dev);
716 }
717 }
718
719
720 /* Find a free SLIP channel, and link in this `tty' line. */
721 static struct slip *sl_alloc(dev_t line)
722 {
723 int i;
724 char name[IFNAMSIZ];
725 struct net_device *dev = NULL;
726 struct slip *sl;
727
728 for (i = 0; i < slip_maxdev; i++) {
729 dev = slip_devs[i];
730 if (dev == NULL)
731 break;
732 }
733 /* Sorry, too many, all slots in use */
734 if (i >= slip_maxdev)
735 return NULL;
736
737 sprintf(name, "sl%d", i);
738 dev = alloc_netdev(sizeof(*sl), name, sl_setup);
739 if (!dev)
740 return NULL;
741
742 dev->base_addr = i;
743 sl = netdev_priv(dev);
744
745 /* Initialize channel control data */
746 sl->magic = SLIP_MAGIC;
747 sl->dev = dev;
748 spin_lock_init(&sl->lock);
749 sl->mode = SL_MODE_DEFAULT;
750 #ifdef CONFIG_SLIP_SMART
751 /* initialize timer_list struct */
752 init_timer(&sl->keepalive_timer);
753 sl->keepalive_timer.data = (unsigned long)sl;
754 sl->keepalive_timer.function = sl_keepalive;
755 init_timer(&sl->outfill_timer);
756 sl->outfill_timer.data = (unsigned long)sl;
757 sl->outfill_timer.function = sl_outfill;
758 #endif
759 slip_devs[i] = dev;
760 return sl;
761 }
762
763 /*
764 * Open the high-level part of the SLIP channel.
765 * This function is called by the TTY module when the
766 * SLIP line discipline is called for. Because we are
767 * sure the tty line exists, we only have to link it to
768 * a free SLIP channel...
769 *
770 * Called in process context serialized from other ldisc calls.
771 */
772
773 static int slip_open(struct tty_struct *tty)
774 {
775 struct slip *sl;
776 int err;
777
778 if (!capable(CAP_NET_ADMIN))
779 return -EPERM;
780
781 if (tty->ops->write == NULL)
782 return -EOPNOTSUPP;
783
784 /* RTnetlink lock is misused here to serialize concurrent
785 opens of slip channels. There are better ways, but it is
786 the simplest one.
787 */
788 rtnl_lock();
789
790 /* Collect hanged up channels. */
791 sl_sync();
792
793 sl = tty->disc_data;
794
795 err = -EEXIST;
796 /* First make sure we're not already connected. */
797 if (sl && sl->magic == SLIP_MAGIC)
798 goto err_exit;
799
800 /* OK. Find a free SLIP channel to use. */
801 err = -ENFILE;
802 sl = sl_alloc(tty_devnum(tty));
803 if (sl == NULL)
804 goto err_exit;
805
806 sl->tty = tty;
807 tty->disc_data = sl;
808 sl->pid = current->pid;
809
810 if (!test_bit(SLF_INUSE, &sl->flags)) {
811 /* Perform the low-level SLIP initialization. */
812 err = sl_alloc_bufs(sl, SL_MTU);
813 if (err)
814 goto err_free_chan;
815
816 set_bit(SLF_INUSE, &sl->flags);
817
818 err = register_netdevice(sl->dev);
819 if (err)
820 goto err_free_bufs;
821 }
822
823 #ifdef CONFIG_SLIP_SMART
824 if (sl->keepalive) {
825 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;
826 add_timer(&sl->keepalive_timer);
827 }
828 if (sl->outfill) {
829 sl->outfill_timer.expires = jiffies + sl->outfill * HZ;
830 add_timer(&sl->outfill_timer);
831 }
832 #endif
833
834 /* Done. We have linked the TTY line to a channel. */
835 rtnl_unlock();
836 tty->receive_room = 65536; /* We don't flow control */
837
838 /* TTY layer expects 0 on success */
839 return 0;
840
841 err_free_bufs:
842 sl_free_bufs(sl);
843
844 err_free_chan:
845 sl->tty = NULL;
846 tty->disc_data = NULL;
847 clear_bit(SLF_INUSE, &sl->flags);
848
849 err_exit:
850 rtnl_unlock();
851
852 /* Count references from TTY module */
853 return err;
854 }
855
856 /*
857 * Close down a SLIP channel.
858 * This means flushing out any pending queues, and then returning. This
859 * call is serialized against other ldisc functions.
860 *
861 * We also use this method fo a hangup event
862 */
863
864 static void slip_close(struct tty_struct *tty)
865 {
866 struct slip *sl = tty->disc_data;
867
868 /* First make sure we're connected. */
869 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
870 return;
871
872 tty->disc_data = NULL;
873 sl->tty = NULL;
874
875 /* VSV = very important to remove timers */
876 #ifdef CONFIG_SLIP_SMART
877 del_timer_sync(&sl->keepalive_timer);
878 del_timer_sync(&sl->outfill_timer);
879 #endif
880 /* Flush network side */
881 unregister_netdev(sl->dev);
882 /* This will complete via sl_free_netdev */
883 }
884
885 static int slip_hangup(struct tty_struct *tty)
886 {
887 slip_close(tty);
888 return 0;
889 }
890 /************************************************************************
891 * STANDARD SLIP ENCAPSULATION *
892 ************************************************************************/
893
894 static int slip_esc(unsigned char *s, unsigned char *d, int len)
895 {
896 unsigned char *ptr = d;
897 unsigned char c;
898
899 /*
900 * Send an initial END character to flush out any
901 * data that may have accumulated in the receiver
902 * due to line noise.
903 */
904
905 *ptr++ = END;
906
907 /*
908 * For each byte in the packet, send the appropriate
909 * character sequence, according to the SLIP protocol.
910 */
911
912 while (len-- > 0) {
913 switch (c = *s++) {
914 case END:
915 *ptr++ = ESC;
916 *ptr++ = ESC_END;
917 break;
918 case ESC:
919 *ptr++ = ESC;
920 *ptr++ = ESC_ESC;
921 break;
922 default:
923 *ptr++ = c;
924 break;
925 }
926 }
927 *ptr++ = END;
928 return ptr - d;
929 }
930
931 static void slip_unesc(struct slip *sl, unsigned char s)
932 {
933
934 switch (s) {
935 case END:
936 #ifdef CONFIG_SLIP_SMART
937 /* drop keeptest bit = VSV */
938 if (test_bit(SLF_KEEPTEST, &sl->flags))
939 clear_bit(SLF_KEEPTEST, &sl->flags);
940 #endif
941
942 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
943 (sl->rcount > 2))
944 sl_bump(sl);
945 clear_bit(SLF_ESCAPE, &sl->flags);
946 sl->rcount = 0;
947 return;
948
949 case ESC:
950 set_bit(SLF_ESCAPE, &sl->flags);
951 return;
952 case ESC_ESC:
953 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
954 s = ESC;
955 break;
956 case ESC_END:
957 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
958 s = END;
959 break;
960 }
961 if (!test_bit(SLF_ERROR, &sl->flags)) {
962 if (sl->rcount < sl->buffsize) {
963 sl->rbuff[sl->rcount++] = s;
964 return;
965 }
966 sl->dev->stats.rx_over_errors++;
967 set_bit(SLF_ERROR, &sl->flags);
968 }
969 }
970
971
972 #ifdef CONFIG_SLIP_MODE_SLIP6
973 /************************************************************************
974 * 6 BIT SLIP ENCAPSULATION *
975 ************************************************************************/
976
977 static int slip_esc6(unsigned char *s, unsigned char *d, int len)
978 {
979 unsigned char *ptr = d;
980 unsigned char c;
981 int i;
982 unsigned short v = 0;
983 short bits = 0;
984
985 /*
986 * Send an initial END character to flush out any
987 * data that may have accumulated in the receiver
988 * due to line noise.
989 */
990
991 *ptr++ = 0x70;
992
993 /*
994 * Encode the packet into printable ascii characters
995 */
996
997 for (i = 0; i < len; ++i) {
998 v = (v << 8) | s[i];
999 bits += 8;
1000 while (bits >= 6) {
1001 bits -= 6;
1002 c = 0x30 + ((v >> bits) & 0x3F);
1003 *ptr++ = c;
1004 }
1005 }
1006 if (bits) {
1007 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1008 *ptr++ = c;
1009 }
1010 *ptr++ = 0x70;
1011 return ptr - d;
1012 }
1013
1014 static void slip_unesc6(struct slip *sl, unsigned char s)
1015 {
1016 unsigned char c;
1017
1018 if (s == 0x70) {
1019 #ifdef CONFIG_SLIP_SMART
1020 /* drop keeptest bit = VSV */
1021 if (test_bit(SLF_KEEPTEST, &sl->flags))
1022 clear_bit(SLF_KEEPTEST, &sl->flags);
1023 #endif
1024
1025 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
1026 (sl->rcount > 2))
1027 sl_bump(sl);
1028 sl->rcount = 0;
1029 sl->xbits = 0;
1030 sl->xdata = 0;
1031 } else if (s >= 0x30 && s < 0x70) {
1032 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1033 sl->xbits += 6;
1034 if (sl->xbits >= 8) {
1035 sl->xbits -= 8;
1036 c = (unsigned char)(sl->xdata >> sl->xbits);
1037 if (!test_bit(SLF_ERROR, &sl->flags)) {
1038 if (sl->rcount < sl->buffsize) {
1039 sl->rbuff[sl->rcount++] = c;
1040 return;
1041 }
1042 sl->dev->stats.rx_over_errors++;
1043 set_bit(SLF_ERROR, &sl->flags);
1044 }
1045 }
1046 }
1047 }
1048 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1049
1050 /* Perform I/O control on an active SLIP channel. */
1051 static int slip_ioctl(struct tty_struct *tty, struct file *file,
1052 unsigned int cmd, unsigned long arg)
1053 {
1054 struct slip *sl = tty->disc_data;
1055 unsigned int tmp;
1056 int __user *p = (int __user *)arg;
1057
1058 /* First make sure we're connected. */
1059 if (!sl || sl->magic != SLIP_MAGIC)
1060 return -EINVAL;
1061
1062 switch (cmd) {
1063 case SIOCGIFNAME:
1064 tmp = strlen(sl->dev->name) + 1;
1065 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1066 return -EFAULT;
1067 return 0;
1068
1069 case SIOCGIFENCAP:
1070 if (put_user(sl->mode, p))
1071 return -EFAULT;
1072 return 0;
1073
1074 case SIOCSIFENCAP:
1075 if (get_user(tmp, p))
1076 return -EFAULT;
1077 #ifndef SL_INCLUDE_CSLIP
1078 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
1079 return -EINVAL;
1080 #else
1081 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1082 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
1083 /* return -EINVAL; */
1084 tmp &= ~SL_MODE_ADAPTIVE;
1085 #endif
1086 #ifndef CONFIG_SLIP_MODE_SLIP6
1087 if (tmp & SL_MODE_SLIP6)
1088 return -EINVAL;
1089 #endif
1090 sl->mode = tmp;
1091 sl->dev->type = ARPHRD_SLIP + sl->mode;
1092 return 0;
1093
1094 case SIOCSIFHWADDR:
1095 return -EINVAL;
1096
1097 #ifdef CONFIG_SLIP_SMART
1098 /* VSV changes start here */
1099 case SIOCSKEEPALIVE:
1100 if (get_user(tmp, p))
1101 return -EFAULT;
1102 if (tmp > 255) /* max for unchar */
1103 return -EINVAL;
1104
1105 spin_lock_bh(&sl->lock);
1106 if (!sl->tty) {
1107 spin_unlock_bh(&sl->lock);
1108 return -ENODEV;
1109 }
1110 sl->keepalive = (u8)tmp;
1111 if (sl->keepalive != 0) {
1112 mod_timer(&sl->keepalive_timer,
1113 jiffies + sl->keepalive * HZ);
1114 set_bit(SLF_KEEPTEST, &sl->flags);
1115 } else
1116 del_timer(&sl->keepalive_timer);
1117 spin_unlock_bh(&sl->lock);
1118 return 0;
1119
1120 case SIOCGKEEPALIVE:
1121 if (put_user(sl->keepalive, p))
1122 return -EFAULT;
1123 return 0;
1124
1125 case SIOCSOUTFILL:
1126 if (get_user(tmp, p))
1127 return -EFAULT;
1128 if (tmp > 255) /* max for unchar */
1129 return -EINVAL;
1130 spin_lock_bh(&sl->lock);
1131 if (!sl->tty) {
1132 spin_unlock_bh(&sl->lock);
1133 return -ENODEV;
1134 }
1135 sl->outfill = (u8)tmp;
1136 if (sl->outfill != 0) {
1137 mod_timer(&sl->outfill_timer,
1138 jiffies + sl->outfill * HZ);
1139 set_bit(SLF_OUTWAIT, &sl->flags);
1140 } else
1141 del_timer(&sl->outfill_timer);
1142 spin_unlock_bh(&sl->lock);
1143 return 0;
1144
1145 case SIOCGOUTFILL:
1146 if (put_user(sl->outfill, p))
1147 return -EFAULT;
1148 return 0;
1149 /* VSV changes end */
1150 #endif
1151 default:
1152 return tty_mode_ioctl(tty, file, cmd, arg);
1153 }
1154 }
1155
1156 #ifdef CONFIG_COMPAT
1157 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
1158 unsigned int cmd, unsigned long arg)
1159 {
1160 switch (cmd) {
1161 case SIOCGIFNAME:
1162 case SIOCGIFENCAP:
1163 case SIOCSIFENCAP:
1164 case SIOCSIFHWADDR:
1165 case SIOCSKEEPALIVE:
1166 case SIOCGKEEPALIVE:
1167 case SIOCSOUTFILL:
1168 case SIOCGOUTFILL:
1169 return slip_ioctl(tty, file, cmd,
1170 (unsigned long)compat_ptr(arg));
1171 }
1172
1173 return -ENOIOCTLCMD;
1174 }
1175 #endif
1176
1177 /* VSV changes start here */
1178 #ifdef CONFIG_SLIP_SMART
1179 /* function do_ioctl called from net/core/dev.c
1180 to allow get/set outfill/keepalive parameter
1181 by ifconfig */
1182
1183 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
1184 {
1185 struct slip *sl = netdev_priv(dev);
1186 unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1187
1188 if (sl == NULL) /* Allocation failed ?? */
1189 return -ENODEV;
1190
1191 spin_lock_bh(&sl->lock);
1192
1193 if (!sl->tty) {
1194 spin_unlock_bh(&sl->lock);
1195 return -ENODEV;
1196 }
1197
1198 switch (cmd) {
1199 case SIOCSKEEPALIVE:
1200 /* max for unchar */
1201 if ((unsigned)*p > 255) {
1202 spin_unlock_bh(&sl->lock);
1203 return -EINVAL;
1204 }
1205 sl->keepalive = (u8)*p;
1206 if (sl->keepalive != 0) {
1207 sl->keepalive_timer.expires =
1208 jiffies + sl->keepalive * HZ;
1209 mod_timer(&sl->keepalive_timer,
1210 jiffies + sl->keepalive * HZ);
1211 set_bit(SLF_KEEPTEST, &sl->flags);
1212 } else
1213 del_timer(&sl->keepalive_timer);
1214 break;
1215
1216 case SIOCGKEEPALIVE:
1217 *p = sl->keepalive;
1218 break;
1219
1220 case SIOCSOUTFILL:
1221 if ((unsigned)*p > 255) { /* max for unchar */
1222 spin_unlock_bh(&sl->lock);
1223 return -EINVAL;
1224 }
1225 sl->outfill = (u8)*p;
1226 if (sl->outfill != 0) {
1227 mod_timer(&sl->outfill_timer,
1228 jiffies + sl->outfill * HZ);
1229 set_bit(SLF_OUTWAIT, &sl->flags);
1230 } else
1231 del_timer(&sl->outfill_timer);
1232 break;
1233
1234 case SIOCGOUTFILL:
1235 *p = sl->outfill;
1236 break;
1237
1238 case SIOCSLEASE:
1239 /* Resolve race condition, when ioctl'ing hanged up
1240 and opened by another process device.
1241 */
1242 if (sl->tty != current->signal->tty &&
1243 sl->pid != current->pid) {
1244 spin_unlock_bh(&sl->lock);
1245 return -EPERM;
1246 }
1247 sl->leased = 0;
1248 if (*p)
1249 sl->leased = 1;
1250 break;
1251
1252 case SIOCGLEASE:
1253 *p = sl->leased;
1254 }
1255 spin_unlock_bh(&sl->lock);
1256 return 0;
1257 }
1258 #endif
1259 /* VSV changes end */
1260
1261 static struct tty_ldisc_ops sl_ldisc = {
1262 .owner = THIS_MODULE,
1263 .magic = TTY_LDISC_MAGIC,
1264 .name = "slip",
1265 .open = slip_open,
1266 .close = slip_close,
1267 .hangup = slip_hangup,
1268 .ioctl = slip_ioctl,
1269 #ifdef CONFIG_COMPAT
1270 .compat_ioctl = slip_compat_ioctl,
1271 #endif
1272 .receive_buf = slip_receive_buf,
1273 .write_wakeup = slip_write_wakeup,
1274 };
1275
1276 static int __init slip_init(void)
1277 {
1278 int status;
1279
1280 if (slip_maxdev < 4)
1281 slip_maxdev = 4; /* Sanity */
1282
1283 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1284 #ifdef CONFIG_SLIP_MODE_SLIP6
1285 " (6 bit encapsulation enabled)"
1286 #endif
1287 ".\n",
1288 SLIP_VERSION, slip_maxdev);
1289 #if defined(SL_INCLUDE_CSLIP)
1290 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1291 #endif
1292 #ifdef CONFIG_SLIP_SMART
1293 printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1294 #endif
1295
1296 slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev,
1297 GFP_KERNEL);
1298 if (!slip_devs)
1299 return -ENOMEM;
1300
1301 /* Fill in our line protocol discipline, and register it */
1302 status = tty_register_ldisc(N_SLIP, &sl_ldisc);
1303 if (status != 0) {
1304 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1305 kfree(slip_devs);
1306 }
1307 return status;
1308 }
1309
1310 static void __exit slip_exit(void)
1311 {
1312 int i;
1313 struct net_device *dev;
1314 struct slip *sl;
1315 unsigned long timeout = jiffies + HZ;
1316 int busy = 0;
1317
1318 if (slip_devs == NULL)
1319 return;
1320
1321 /* First of all: check for active disciplines and hangup them.
1322 */
1323 do {
1324 if (busy)
1325 msleep_interruptible(100);
1326
1327 busy = 0;
1328 for (i = 0; i < slip_maxdev; i++) {
1329 dev = slip_devs[i];
1330 if (!dev)
1331 continue;
1332 sl = netdev_priv(dev);
1333 spin_lock_bh(&sl->lock);
1334 if (sl->tty) {
1335 busy++;
1336 tty_hangup(sl->tty);
1337 }
1338 spin_unlock_bh(&sl->lock);
1339 }
1340 } while (busy && time_before(jiffies, timeout));
1341
1342 /* FIXME: hangup is async so we should wait when doing this second
1343 phase */
1344
1345 for (i = 0; i < slip_maxdev; i++) {
1346 dev = slip_devs[i];
1347 if (!dev)
1348 continue;
1349 slip_devs[i] = NULL;
1350
1351 sl = netdev_priv(dev);
1352 if (sl->tty) {
1353 printk(KERN_ERR "%s: tty discipline still running\n",
1354 dev->name);
1355 /* Intentionally leak the control block. */
1356 dev->destructor = NULL;
1357 }
1358
1359 unregister_netdev(dev);
1360 }
1361
1362 kfree(slip_devs);
1363 slip_devs = NULL;
1364
1365 i = tty_unregister_ldisc(N_SLIP);
1366 if (i != 0)
1367 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i);
1368 }
1369
1370 module_init(slip_init);
1371 module_exit(slip_exit);
1372
1373 #ifdef CONFIG_SLIP_SMART
1374 /*
1375 * This is start of the code for multislip style line checking
1376 * added by Stanislav Voronyi. All changes before marked VSV
1377 */
1378
1379 static void sl_outfill(unsigned long sls)
1380 {
1381 struct slip *sl = (struct slip *)sls;
1382
1383 spin_lock(&sl->lock);
1384
1385 if (sl->tty == NULL)
1386 goto out;
1387
1388 if (sl->outfill) {
1389 if (test_bit(SLF_OUTWAIT, &sl->flags)) {
1390 /* no packets were transmitted, do outfill */
1391 #ifdef CONFIG_SLIP_MODE_SLIP6
1392 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1393 #else
1394 unsigned char s = END;
1395 #endif
1396 /* put END into tty queue. Is it right ??? */
1397 if (!netif_queue_stopped(sl->dev)) {
1398 /* if device busy no outfill */
1399 sl->tty->ops->write(sl->tty, &s, 1);
1400 }
1401 } else
1402 set_bit(SLF_OUTWAIT, &sl->flags);
1403
1404 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1405 }
1406 out:
1407 spin_unlock(&sl->lock);
1408 }
1409
1410 static void sl_keepalive(unsigned long sls)
1411 {
1412 struct slip *sl = (struct slip *)sls;
1413
1414 spin_lock(&sl->lock);
1415
1416 if (sl->tty == NULL)
1417 goto out;
1418
1419 if (sl->keepalive) {
1420 if (test_bit(SLF_KEEPTEST, &sl->flags)) {
1421 /* keepalive still high :(, we must hangup */
1422 if (sl->outfill)
1423 /* outfill timer must be deleted too */
1424 (void)del_timer(&sl->outfill_timer);
1425 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1426 /* this must hangup tty & close slip */
1427 tty_hangup(sl->tty);
1428 /* I think we need not something else */
1429 goto out;
1430 } else
1431 set_bit(SLF_KEEPTEST, &sl->flags);
1432
1433 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1434 }
1435 out:
1436 spin_unlock(&sl->lock);
1437 }
1438
1439 #endif
1440 MODULE_LICENSE("GPL");
1441 MODULE_ALIAS_LDISC(N_SLIP);
1442