1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * slip.c This module implements the SLIP protocol for kernel-based
4 * devices like TTY. It interfaces between a raw TTY, and the
5 * kernel's INET protocol layers.
6 *
7 * Version: @(#)slip.c 0.8.3 12/24/94
8 *
9 * Authors: Laurence Culhane, <loz@holmes.demon.co.uk>
10 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
11 *
12 * Fixes:
13 * Alan Cox : Sanity checks and avoid tx overruns.
14 * Has a new sl->mtu field.
15 * Alan Cox : Found cause of overrun. ifconfig sl0
16 * mtu upwards. Driver now spots this
17 * and grows/shrinks its buffers(hack!).
18 * Memory leak if you run out of memory
19 * setting up a slip driver fixed.
20 * Matt Dillon : Printable slip (borrowed from NET2E)
21 * Pauline Middelink : Slip driver fixes.
22 * Alan Cox : Honours the old SL_COMPRESSED flag
23 * Alan Cox : KISS AX.25 and AXUI IP support
24 * Michael Riepe : Automatic CSLIP recognition added
25 * Charles Hedrick : CSLIP header length problem fix.
26 * Alan Cox : Corrected non-IP cases of the above.
27 * Alan Cox : Now uses hardware type as per FvK.
28 * Alan Cox : Default to 192.168.0.0 (RFC 1597)
29 * A.N.Kuznetsov : dev_tint() recursion fix.
30 * Dmitry Gorodchanin : SLIP memory leaks
31 * Dmitry Gorodchanin : Code cleanup. Reduce tty driver
32 * buffering from 4096 to 256 bytes.
33 * Improving SLIP response time.
34 * CONFIG_SLIP_MODE_SLIP6.
35 * ifconfig sl? up & down now works
36 * correctly.
37 * Modularization.
38 * Alan Cox : Oops - fix AX.25 buffer lengths
39 * Dmitry Gorodchanin : Even more cleanups. Preserve CSLIP
40 * statistics. Include CSLIP code only
41 * if it really needed.
42 * Alan Cox : Free slhc buffers in the right place.
43 * Alan Cox : Allow for digipeated IP over AX.25
44 * Matti Aarnio : Dynamic SLIP devices, with ideas taken
45 * from Jim Freeman's <jfree@caldera.com>
46 * dynamic PPP devices. We do NOT kfree()
47 * device entries, just reg./unreg. them
48 * as they are needed. We kfree() them
49 * at module cleanup.
50 * With MODULE-loading ``insmod'', user
51 * can issue parameter: slip_maxdev=1024
52 * (Or how much he/she wants.. Default
53 * is 256)
54 * Stanislav Voronyi : Slip line checking, with ideas taken
55 * from multislip BSDI driver which was
56 * written by Igor Chechik, RELCOM Corp.
57 * Only algorithms have been ported to
58 * Linux SLIP driver.
59 * Vitaly E. Lavrov : Sane behaviour on tty hangup.
60 * Alexey Kuznetsov : Cleanup interfaces to tty & netdevice
61 * modules.
62 */
63
64 #define SL_CHECK_TRANSMIT
65 #include <linux/compat.h>
66 #include <linux/module.h>
67 #include <linux/moduleparam.h>
68
69 #include <linux/uaccess.h>
70 #include <linux/bitops.h>
71 #include <linux/sched/signal.h>
72 #include <linux/string.h>
73 #include <linux/mm.h>
74 #include <linux/interrupt.h>
75 #include <linux/in.h>
76 #include <linux/tty.h>
77 #include <linux/errno.h>
78 #include <linux/netdevice.h>
79 #include <linux/etherdevice.h>
80 #include <linux/skbuff.h>
81 #include <linux/rtnetlink.h>
82 #include <linux/if_arp.h>
83 #include <linux/if_slip.h>
84 #include <linux/delay.h>
85 #include <linux/init.h>
86 #include <linux/slab.h>
87 #include <linux/workqueue.h>
88 #include "slip.h"
89 #ifdef CONFIG_INET
90 #include <linux/ip.h>
91 #include <linux/tcp.h>
92 #include <net/slhc_vj.h>
93 #endif
94
95 #define SLIP_VERSION "0.8.4-NET3.019-NEWTTY"
96
97 static struct net_device **slip_devs;
98
99 static int slip_maxdev = SL_NRUNIT;
100 module_param(slip_maxdev, int, 0);
101 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");
102
103 static int slip_esc(unsigned char *p, unsigned char *d, int len);
104 static void slip_unesc(struct slip *sl, unsigned char c);
105 #ifdef CONFIG_SLIP_MODE_SLIP6
106 static int slip_esc6(unsigned char *p, unsigned char *d, int len);
107 static void slip_unesc6(struct slip *sl, unsigned char c);
108 #endif
109 #ifdef CONFIG_SLIP_SMART
110 static void sl_keepalive(struct timer_list *t);
111 static void sl_outfill(struct timer_list *t);
112 static int sl_siocdevprivate(struct net_device *dev, struct ifreq *rq, void __user *data, int cmd);
113 #endif
114
115 /********************************
116 * Buffer administration routines:
117 * sl_alloc_bufs()
118 * sl_free_bufs()
119 * sl_realloc_bufs()
120 *
121 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because
122 * sl_realloc_bufs provides strong atomicity and reallocation
123 * on actively running device.
124 *********************************/
125
126 /*
127 Allocate channel buffers.
128 */
129
sl_alloc_bufs(struct slip * sl,int mtu)130 static int sl_alloc_bufs(struct slip *sl, int mtu)
131 {
132 int err = -ENOBUFS;
133 unsigned long len;
134 char *rbuff = NULL;
135 char *xbuff = NULL;
136 #ifdef SL_INCLUDE_CSLIP
137 char *cbuff = NULL;
138 struct slcompress *slcomp = NULL;
139 #endif
140
141 /*
142 * Allocate the SLIP frame buffers:
143 *
144 * rbuff Receive buffer.
145 * xbuff Transmit buffer.
146 * cbuff Temporary compression buffer.
147 */
148 len = mtu * 2;
149
150 /*
151 * allow for arrival of larger UDP packets, even if we say not to
152 * also fixes a bug in which SunOS sends 512-byte packets even with
153 * an MSS of 128
154 */
155 if (len < 576 * 2)
156 len = 576 * 2;
157 rbuff = kmalloc(len + 4, GFP_KERNEL);
158 if (rbuff == NULL)
159 goto err_exit;
160 xbuff = kmalloc(len + 4, GFP_KERNEL);
161 if (xbuff == NULL)
162 goto err_exit;
163 #ifdef SL_INCLUDE_CSLIP
164 cbuff = kmalloc(len + 4, GFP_KERNEL);
165 if (cbuff == NULL)
166 goto err_exit;
167 slcomp = slhc_init(16, 16);
168 if (IS_ERR(slcomp))
169 goto err_exit;
170 #endif
171 spin_lock_bh(&sl->lock);
172 if (sl->tty == NULL) {
173 spin_unlock_bh(&sl->lock);
174 err = -ENODEV;
175 goto err_exit;
176 }
177 sl->mtu = mtu;
178 sl->buffsize = len;
179 sl->rcount = 0;
180 sl->xleft = 0;
181 rbuff = xchg(&sl->rbuff, rbuff);
182 xbuff = xchg(&sl->xbuff, xbuff);
183 #ifdef SL_INCLUDE_CSLIP
184 cbuff = xchg(&sl->cbuff, cbuff);
185 slcomp = xchg(&sl->slcomp, slcomp);
186 #endif
187 #ifdef CONFIG_SLIP_MODE_SLIP6
188 sl->xdata = 0;
189 sl->xbits = 0;
190 #endif
191 spin_unlock_bh(&sl->lock);
192 err = 0;
193
194 /* Cleanup */
195 err_exit:
196 #ifdef SL_INCLUDE_CSLIP
197 kfree(cbuff);
198 slhc_free(slcomp);
199 #endif
200 kfree(xbuff);
201 kfree(rbuff);
202 return err;
203 }
204
205 /* Free a SLIP channel buffers. */
sl_free_bufs(struct slip * sl)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
sl_realloc_bufs(struct slip * sl,int mtu)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 WRITE_ONCE(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 skb_put_data(skb, 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, sl->xbuff, len);
396 else
397 #endif
398 count = slip_esc(p, 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 netif_trans_update(sl->dev);
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 /* Write out any remaining transmit buffer. Scheduled when tty is writable */
422 static void slip_transmit(struct work_struct *work)
423 {
424 struct slip *sl = container_of(work, struct slip, tx_work);
425 int actual;
426
427 spin_lock_bh(&sl->lock);
428 /* First make sure we're connected. */
429 if (!sl->tty || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) {
430 spin_unlock_bh(&sl->lock);
431 return;
432 }
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, &sl->tty->flags);
439 spin_unlock_bh(&sl->lock);
440 sl_unlock(sl);
441 return;
442 }
443
444 actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
445 sl->xleft -= actual;
446 sl->xhead += actual;
447 spin_unlock_bh(&sl->lock);
448 }
449
450 /*
451 * Called by the driver when there's room for more data.
452 * Schedule the transmit.
453 */
454 static void slip_write_wakeup(struct tty_struct *tty)
455 {
456 struct slip *sl;
457
458 rcu_read_lock();
459 sl = rcu_dereference(tty->disc_data);
460 if (sl)
461 schedule_work(&sl->tx_work);
462 rcu_read_unlock();
463 }
464
465 static void sl_tx_timeout(struct net_device *dev, unsigned int txqueue)
466 {
467 struct slip *sl = netdev_priv(dev);
468
469 spin_lock(&sl->lock);
470
471 if (netif_queue_stopped(dev)) {
472 if (!netif_running(dev) || !sl->tty)
473 goto out;
474
475 /* May be we must check transmitter timeout here ?
476 * 14 Oct 1994 Dmitry Gorodchanin.
477 */
478 #ifdef SL_CHECK_TRANSMIT
479 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) {
480 /* 20 sec timeout not reached */
481 goto out;
482 }
483 printk(KERN_WARNING "%s: transmit timed out, %s?\n",
484 dev->name,
485 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
486 "bad line quality" : "driver error");
487 sl->xleft = 0;
488 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
489 sl_unlock(sl);
490 #endif
491 }
492 out:
493 spin_unlock(&sl->lock);
494 }
495
496
497 /* Encapsulate an IP datagram and kick it into a TTY queue. */
498 static netdev_tx_t
499 sl_xmit(struct sk_buff *skb, struct net_device *dev)
500 {
501 struct slip *sl = netdev_priv(dev);
502
503 spin_lock(&sl->lock);
504 if (!netif_running(dev)) {
505 spin_unlock(&sl->lock);
506 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);
507 dev_kfree_skb(skb);
508 return NETDEV_TX_OK;
509 }
510 if (sl->tty == NULL) {
511 spin_unlock(&sl->lock);
512 dev_kfree_skb(skb);
513 return NETDEV_TX_OK;
514 }
515
516 sl_lock(sl);
517 dev->stats.tx_bytes += skb->len;
518 sl_encaps(sl, skb->data, skb->len);
519 spin_unlock(&sl->lock);
520
521 dev_kfree_skb(skb);
522 return NETDEV_TX_OK;
523 }
524
525
526 /******************************************
527 * Routines looking at netdevice side.
528 ******************************************/
529
530 /* Netdevice UP -> DOWN routine */
531
532 static int
533 sl_close(struct net_device *dev)
534 {
535 struct slip *sl = netdev_priv(dev);
536
537 spin_lock_bh(&sl->lock);
538 if (sl->tty)
539 /* TTY discipline is running. */
540 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
541 netif_stop_queue(dev);
542 sl->rcount = 0;
543 sl->xleft = 0;
544 spin_unlock_bh(&sl->lock);
545
546 return 0;
547 }
548
549 /* Netdevice DOWN -> UP routine */
550
551 static int sl_open(struct net_device *dev)
552 {
553 struct slip *sl = netdev_priv(dev);
554
555 if (sl->tty == NULL)
556 return -ENODEV;
557
558 sl->flags &= (1 << SLF_INUSE);
559 netif_start_queue(dev);
560 return 0;
561 }
562
563 /* Netdevice change MTU request */
564
565 static int sl_change_mtu(struct net_device *dev, int new_mtu)
566 {
567 struct slip *sl = netdev_priv(dev);
568
569 return sl_realloc_bufs(sl, new_mtu);
570 }
571
572 /* Netdevice get statistics request */
573
574 static void
575 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
576 {
577 struct net_device_stats *devstats = &dev->stats;
578 #ifdef SL_INCLUDE_CSLIP
579 struct slip *sl = netdev_priv(dev);
580 struct slcompress *comp = sl->slcomp;
581 #endif
582 stats->rx_packets = devstats->rx_packets;
583 stats->tx_packets = devstats->tx_packets;
584 stats->rx_bytes = devstats->rx_bytes;
585 stats->tx_bytes = devstats->tx_bytes;
586 stats->rx_dropped = devstats->rx_dropped;
587 stats->tx_dropped = devstats->tx_dropped;
588 stats->tx_errors = devstats->tx_errors;
589 stats->rx_errors = devstats->rx_errors;
590 stats->rx_over_errors = devstats->rx_over_errors;
591
592 #ifdef SL_INCLUDE_CSLIP
593 if (comp) {
594 /* Generic compressed statistics */
595 stats->rx_compressed = comp->sls_i_compressed;
596 stats->tx_compressed = comp->sls_o_compressed;
597
598 /* Are we really still needs this? */
599 stats->rx_fifo_errors += comp->sls_i_compressed;
600 stats->rx_dropped += comp->sls_i_tossed;
601 stats->tx_fifo_errors += comp->sls_o_compressed;
602 stats->collisions += comp->sls_o_misses;
603 }
604 #endif
605 }
606
607 /* Netdevice register callback */
608
609 static int sl_init(struct net_device *dev)
610 {
611 struct slip *sl = netdev_priv(dev);
612
613 /*
614 * Finish setting up the DEVICE info.
615 */
616
617 dev->mtu = sl->mtu;
618 dev->type = ARPHRD_SLIP + sl->mode;
619 #ifdef SL_CHECK_TRANSMIT
620 dev->watchdog_timeo = 20*HZ;
621 #endif
622 return 0;
623 }
624
625
626 static void sl_uninit(struct net_device *dev)
627 {
628 struct slip *sl = netdev_priv(dev);
629
630 sl_free_bufs(sl);
631 }
632
633 /* Hook the destructor so we can free slip devices at the right point in time */
634 static void sl_free_netdev(struct net_device *dev)
635 {
636 int i = dev->base_addr;
637
638 slip_devs[i] = NULL;
639 }
640
641 static const struct net_device_ops sl_netdev_ops = {
642 .ndo_init = sl_init,
643 .ndo_uninit = sl_uninit,
644 .ndo_open = sl_open,
645 .ndo_stop = sl_close,
646 .ndo_start_xmit = sl_xmit,
647 .ndo_get_stats64 = sl_get_stats64,
648 .ndo_change_mtu = sl_change_mtu,
649 .ndo_tx_timeout = sl_tx_timeout,
650 #ifdef CONFIG_SLIP_SMART
651 .ndo_siocdevprivate = sl_siocdevprivate,
652 #endif
653 };
654
655
656 static void sl_setup(struct net_device *dev)
657 {
658 dev->netdev_ops = &sl_netdev_ops;
659 dev->needs_free_netdev = true;
660 dev->priv_destructor = sl_free_netdev;
661
662 dev->hard_header_len = 0;
663 dev->addr_len = 0;
664 dev->tx_queue_len = 10;
665
666 /* MTU range: 68 - 65534 */
667 dev->min_mtu = 68;
668 dev->max_mtu = 65534;
669
670 /* New-style flags. */
671 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;
672 }
673
674 /******************************************
675 Routines looking at TTY side.
676 ******************************************/
677
678
679 /*
680 * Handle the 'receiver data ready' interrupt.
681 * This function is called by the 'tty_io' module in the kernel when
682 * a block of SLIP data has been received, which can now be decapsulated
683 * and sent on to some IP layer for further processing. This will not
684 * be re-entered while running but other ldisc functions may be called
685 * in parallel
686 */
687
688 static void slip_receive_buf(struct tty_struct *tty, const u8 *cp, const u8 *fp,
689 size_t count)
690 {
691 struct slip *sl = tty->disc_data;
692
693 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
694 return;
695
696 spin_lock_bh(&sl->lock);
697
698 /* Read the characters out of the buffer */
699 while (count--) {
700 if (fp && *fp++) {
701 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
702 sl->dev->stats.rx_errors++;
703 cp++;
704 continue;
705 }
706 #ifdef CONFIG_SLIP_MODE_SLIP6
707 if (sl->mode & SL_MODE_SLIP6)
708 slip_unesc6(sl, *cp++);
709 else
710 #endif
711 slip_unesc(sl, *cp++);
712 }
713
714 spin_unlock_bh(&sl->lock);
715 }
716
717 /************************************
718 * slip_open helper routines.
719 ************************************/
720
721 /* Collect hanged up channels */
722 static void sl_sync(void)
723 {
724 int i;
725 struct net_device *dev;
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 sl = netdev_priv(dev);
734 if (sl->tty || sl->leased)
735 continue;
736 if (dev->flags & IFF_UP)
737 dev_close(dev);
738 }
739 }
740
741
742 /* Find a free SLIP channel, and link in this `tty' line. */
743 static struct slip *sl_alloc(void)
744 {
745 int i;
746 char name[IFNAMSIZ];
747 struct net_device *dev = NULL;
748 struct slip *sl;
749
750 for (i = 0; i < slip_maxdev; i++) {
751 dev = slip_devs[i];
752 if (dev == NULL)
753 break;
754 }
755 /* Sorry, too many, all slots in use */
756 if (i >= slip_maxdev)
757 return NULL;
758
759 sprintf(name, "sl%d", i);
760 dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup);
761 if (!dev)
762 return NULL;
763
764 dev->base_addr = i;
765 sl = netdev_priv(dev);
766
767 /* Initialize channel control data */
768 sl->magic = SLIP_MAGIC;
769 sl->dev = dev;
770 spin_lock_init(&sl->lock);
771 INIT_WORK(&sl->tx_work, slip_transmit);
772 sl->mode = SL_MODE_DEFAULT;
773 #ifdef CONFIG_SLIP_SMART
774 /* initialize timer_list struct */
775 timer_setup(&sl->keepalive_timer, sl_keepalive, 0);
776 timer_setup(&sl->outfill_timer, sl_outfill, 0);
777 #endif
778 slip_devs[i] = dev;
779 return sl;
780 }
781
782 /*
783 * Open the high-level part of the SLIP channel.
784 * This function is called by the TTY module when the
785 * SLIP line discipline is called for. Because we are
786 * sure the tty line exists, we only have to link it to
787 * a free SLIP channel...
788 *
789 * Called in process context serialized from other ldisc calls.
790 */
791
792 static int slip_open(struct tty_struct *tty)
793 {
794 struct slip *sl;
795 int err;
796
797 if (!capable(CAP_NET_ADMIN))
798 return -EPERM;
799
800 if (tty->ops->write == NULL)
801 return -EOPNOTSUPP;
802
803 /* RTnetlink lock is misused here to serialize concurrent
804 opens of slip channels. There are better ways, but it is
805 the simplest one.
806 */
807 rtnl_lock();
808
809 /* Collect hanged up channels. */
810 sl_sync();
811
812 sl = tty->disc_data;
813
814 err = -EEXIST;
815 /* First make sure we're not already connected. */
816 if (sl && sl->magic == SLIP_MAGIC)
817 goto err_exit;
818
819 /* OK. Find a free SLIP channel to use. */
820 err = -ENFILE;
821 sl = sl_alloc();
822 if (sl == NULL)
823 goto err_exit;
824
825 sl->tty = tty;
826 tty->disc_data = sl;
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
857 /* TTY layer expects 0 on success */
858 return 0;
859
860 err_free_bufs:
861 sl_free_bufs(sl);
862
863 err_free_chan:
864 sl->tty = NULL;
865 tty->disc_data = NULL;
866 clear_bit(SLF_INUSE, &sl->flags);
867 sl_free_netdev(sl->dev);
868 /* do not call free_netdev before rtnl_unlock */
869 rtnl_unlock();
870 free_netdev(sl->dev);
871 return err;
872
873 err_exit:
874 rtnl_unlock();
875
876 /* Count references from TTY module */
877 return err;
878 }
879
880 /*
881 * Close down a SLIP channel.
882 * This means flushing out any pending queues, and then returning. This
883 * call is serialized against other ldisc functions.
884 *
885 * We also use this method fo a hangup event
886 */
887
888 static void slip_close(struct tty_struct *tty)
889 {
890 struct slip *sl = tty->disc_data;
891
892 /* First make sure we're connected. */
893 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
894 return;
895
896 spin_lock_bh(&sl->lock);
897 rcu_assign_pointer(tty->disc_data, NULL);
898 sl->tty = NULL;
899 spin_unlock_bh(&sl->lock);
900
901 synchronize_rcu();
902 flush_work(&sl->tx_work);
903
904 /* VSV = very important to remove timers */
905 #ifdef CONFIG_SLIP_SMART
906 timer_delete_sync(&sl->keepalive_timer);
907 timer_delete_sync(&sl->outfill_timer);
908 #endif
909 /* Flush network side */
910 unregister_netdev(sl->dev);
911 /* This will complete via sl_free_netdev */
912 }
913
914 static void slip_hangup(struct tty_struct *tty)
915 {
916 slip_close(tty);
917 }
918 /************************************************************************
919 * STANDARD SLIP ENCAPSULATION *
920 ************************************************************************/
921
922 static int slip_esc(unsigned char *s, unsigned char *d, int len)
923 {
924 unsigned char *ptr = d;
925 unsigned char c;
926
927 /*
928 * Send an initial END character to flush out any
929 * data that may have accumulated in the receiver
930 * due to line noise.
931 */
932
933 *ptr++ = END;
934
935 /*
936 * For each byte in the packet, send the appropriate
937 * character sequence, according to the SLIP protocol.
938 */
939
940 while (len-- > 0) {
941 switch (c = *s++) {
942 case END:
943 *ptr++ = ESC;
944 *ptr++ = ESC_END;
945 break;
946 case ESC:
947 *ptr++ = ESC;
948 *ptr++ = ESC_ESC;
949 break;
950 default:
951 *ptr++ = c;
952 break;
953 }
954 }
955 *ptr++ = END;
956 return ptr - d;
957 }
958
959 static void slip_unesc(struct slip *sl, unsigned char s)
960 {
961
962 switch (s) {
963 case END:
964 #ifdef CONFIG_SLIP_SMART
965 /* drop keeptest bit = VSV */
966 if (test_bit(SLF_KEEPTEST, &sl->flags))
967 clear_bit(SLF_KEEPTEST, &sl->flags);
968 #endif
969
970 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
971 (sl->rcount > 2))
972 sl_bump(sl);
973 clear_bit(SLF_ESCAPE, &sl->flags);
974 sl->rcount = 0;
975 return;
976
977 case ESC:
978 set_bit(SLF_ESCAPE, &sl->flags);
979 return;
980 case ESC_ESC:
981 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
982 s = ESC;
983 break;
984 case ESC_END:
985 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
986 s = END;
987 break;
988 }
989 if (!test_bit(SLF_ERROR, &sl->flags)) {
990 if (sl->rcount < sl->buffsize) {
991 sl->rbuff[sl->rcount++] = s;
992 return;
993 }
994 sl->dev->stats.rx_over_errors++;
995 set_bit(SLF_ERROR, &sl->flags);
996 }
997 }
998
999
1000 #ifdef CONFIG_SLIP_MODE_SLIP6
1001 /************************************************************************
1002 * 6 BIT SLIP ENCAPSULATION *
1003 ************************************************************************/
1004
1005 static int slip_esc6(unsigned char *s, unsigned char *d, int len)
1006 {
1007 unsigned char *ptr = d;
1008 unsigned char c;
1009 int i;
1010 unsigned short v = 0;
1011 short bits = 0;
1012
1013 /*
1014 * Send an initial END character to flush out any
1015 * data that may have accumulated in the receiver
1016 * due to line noise.
1017 */
1018
1019 *ptr++ = 0x70;
1020
1021 /*
1022 * Encode the packet into printable ascii characters
1023 */
1024
1025 for (i = 0; i < len; ++i) {
1026 v = (v << 8) | s[i];
1027 bits += 8;
1028 while (bits >= 6) {
1029 bits -= 6;
1030 c = 0x30 + ((v >> bits) & 0x3F);
1031 *ptr++ = c;
1032 }
1033 }
1034 if (bits) {
1035 c = 0x30 + ((v << (6 - bits)) & 0x3F);
1036 *ptr++ = c;
1037 }
1038 *ptr++ = 0x70;
1039 return ptr - d;
1040 }
1041
1042 static void slip_unesc6(struct slip *sl, unsigned char s)
1043 {
1044 unsigned char c;
1045
1046 if (s == 0x70) {
1047 #ifdef CONFIG_SLIP_SMART
1048 /* drop keeptest bit = VSV */
1049 if (test_bit(SLF_KEEPTEST, &sl->flags))
1050 clear_bit(SLF_KEEPTEST, &sl->flags);
1051 #endif
1052
1053 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
1054 (sl->rcount > 2))
1055 sl_bump(sl);
1056 sl->rcount = 0;
1057 sl->xbits = 0;
1058 sl->xdata = 0;
1059 } else if (s >= 0x30 && s < 0x70) {
1060 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F);
1061 sl->xbits += 6;
1062 if (sl->xbits >= 8) {
1063 sl->xbits -= 8;
1064 c = (unsigned char)(sl->xdata >> sl->xbits);
1065 if (!test_bit(SLF_ERROR, &sl->flags)) {
1066 if (sl->rcount < sl->buffsize) {
1067 sl->rbuff[sl->rcount++] = c;
1068 return;
1069 }
1070 sl->dev->stats.rx_over_errors++;
1071 set_bit(SLF_ERROR, &sl->flags);
1072 }
1073 }
1074 }
1075 }
1076 #endif /* CONFIG_SLIP_MODE_SLIP6 */
1077
1078 /* Perform I/O control on an active SLIP channel. */
1079 static int slip_ioctl(struct tty_struct *tty, unsigned int cmd,
1080 unsigned long arg)
1081 {
1082 struct slip *sl = tty->disc_data;
1083 unsigned int tmp;
1084 int __user *p = (int __user *)arg;
1085
1086 /* First make sure we're connected. */
1087 if (!sl || sl->magic != SLIP_MAGIC)
1088 return -EINVAL;
1089
1090 switch (cmd) {
1091 case SIOCGIFNAME:
1092 tmp = strlen(sl->dev->name) + 1;
1093 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1094 return -EFAULT;
1095 return 0;
1096
1097 case SIOCGIFENCAP:
1098 if (put_user(sl->mode, p))
1099 return -EFAULT;
1100 return 0;
1101
1102 case SIOCSIFENCAP:
1103 if (get_user(tmp, p))
1104 return -EFAULT;
1105 #ifndef SL_INCLUDE_CSLIP
1106 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))
1107 return -EINVAL;
1108 #else
1109 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==
1110 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))
1111 /* return -EINVAL; */
1112 tmp &= ~SL_MODE_ADAPTIVE;
1113 #endif
1114 #ifndef CONFIG_SLIP_MODE_SLIP6
1115 if (tmp & SL_MODE_SLIP6)
1116 return -EINVAL;
1117 #endif
1118 sl->mode = tmp;
1119 sl->dev->type = ARPHRD_SLIP + sl->mode;
1120 return 0;
1121
1122 case SIOCSIFHWADDR:
1123 return -EINVAL;
1124
1125 #ifdef CONFIG_SLIP_SMART
1126 /* VSV changes start here */
1127 case SIOCSKEEPALIVE:
1128 if (get_user(tmp, p))
1129 return -EFAULT;
1130 if (tmp > 255) /* max for unchar */
1131 return -EINVAL;
1132
1133 spin_lock_bh(&sl->lock);
1134 if (!sl->tty) {
1135 spin_unlock_bh(&sl->lock);
1136 return -ENODEV;
1137 }
1138 sl->keepalive = (u8)tmp;
1139 if (sl->keepalive != 0) {
1140 mod_timer(&sl->keepalive_timer,
1141 jiffies + sl->keepalive * HZ);
1142 set_bit(SLF_KEEPTEST, &sl->flags);
1143 } else
1144 timer_delete(&sl->keepalive_timer);
1145 spin_unlock_bh(&sl->lock);
1146 return 0;
1147
1148 case SIOCGKEEPALIVE:
1149 if (put_user(sl->keepalive, p))
1150 return -EFAULT;
1151 return 0;
1152
1153 case SIOCSOUTFILL:
1154 if (get_user(tmp, p))
1155 return -EFAULT;
1156 if (tmp > 255) /* max for unchar */
1157 return -EINVAL;
1158 spin_lock_bh(&sl->lock);
1159 if (!sl->tty) {
1160 spin_unlock_bh(&sl->lock);
1161 return -ENODEV;
1162 }
1163 sl->outfill = (u8)tmp;
1164 if (sl->outfill != 0) {
1165 mod_timer(&sl->outfill_timer,
1166 jiffies + sl->outfill * HZ);
1167 set_bit(SLF_OUTWAIT, &sl->flags);
1168 } else
1169 timer_delete(&sl->outfill_timer);
1170 spin_unlock_bh(&sl->lock);
1171 return 0;
1172
1173 case SIOCGOUTFILL:
1174 if (put_user(sl->outfill, p))
1175 return -EFAULT;
1176 return 0;
1177 /* VSV changes end */
1178 #endif
1179 default:
1180 return tty_mode_ioctl(tty, cmd, arg);
1181 }
1182 }
1183
1184 /* VSV changes start here */
1185 #ifdef CONFIG_SLIP_SMART
1186 /* function sl_siocdevprivate called from net/core/dev.c
1187 to allow get/set outfill/keepalive parameter
1188 by ifconfig */
1189
1190 static int sl_siocdevprivate(struct net_device *dev, struct ifreq *rq,
1191 void __user *data, int cmd)
1192 {
1193 struct slip *sl = netdev_priv(dev);
1194 unsigned long *p = (unsigned long *)&rq->ifr_ifru;
1195
1196 if (sl == NULL) /* Allocation failed ?? */
1197 return -ENODEV;
1198
1199 if (in_compat_syscall())
1200 return -EOPNOTSUPP;
1201
1202 spin_lock_bh(&sl->lock);
1203
1204 if (!sl->tty) {
1205 spin_unlock_bh(&sl->lock);
1206 return -ENODEV;
1207 }
1208
1209 switch (cmd) {
1210 case SIOCSKEEPALIVE:
1211 /* max for unchar */
1212 if ((unsigned)*p > 255) {
1213 spin_unlock_bh(&sl->lock);
1214 return -EINVAL;
1215 }
1216 sl->keepalive = (u8)*p;
1217 if (sl->keepalive != 0) {
1218 sl->keepalive_timer.expires =
1219 jiffies + sl->keepalive * HZ;
1220 mod_timer(&sl->keepalive_timer,
1221 jiffies + sl->keepalive * HZ);
1222 set_bit(SLF_KEEPTEST, &sl->flags);
1223 } else
1224 timer_delete(&sl->keepalive_timer);
1225 break;
1226
1227 case SIOCGKEEPALIVE:
1228 *p = sl->keepalive;
1229 break;
1230
1231 case SIOCSOUTFILL:
1232 if ((unsigned)*p > 255) { /* max for unchar */
1233 spin_unlock_bh(&sl->lock);
1234 return -EINVAL;
1235 }
1236 sl->outfill = (u8)*p;
1237 if (sl->outfill != 0) {
1238 mod_timer(&sl->outfill_timer,
1239 jiffies + sl->outfill * HZ);
1240 set_bit(SLF_OUTWAIT, &sl->flags);
1241 } else
1242 timer_delete(&sl->outfill_timer);
1243 break;
1244
1245 case SIOCGOUTFILL:
1246 *p = sl->outfill;
1247 break;
1248
1249 case SIOCSLEASE:
1250 /* Resolve race condition, when ioctl'ing hanged up
1251 and opened by another process device.
1252 */
1253 if (sl->tty != current->signal->tty &&
1254 sl->pid != current->pid) {
1255 spin_unlock_bh(&sl->lock);
1256 return -EPERM;
1257 }
1258 sl->leased = 0;
1259 if (*p)
1260 sl->leased = 1;
1261 break;
1262
1263 case SIOCGLEASE:
1264 *p = sl->leased;
1265 }
1266 spin_unlock_bh(&sl->lock);
1267 return 0;
1268 }
1269 #endif
1270 /* VSV changes end */
1271
1272 static struct tty_ldisc_ops sl_ldisc = {
1273 .owner = THIS_MODULE,
1274 .num = N_SLIP,
1275 .name = "slip",
1276 .open = slip_open,
1277 .close = slip_close,
1278 .hangup = slip_hangup,
1279 .ioctl = slip_ioctl,
1280 .receive_buf = slip_receive_buf,
1281 .write_wakeup = slip_write_wakeup,
1282 };
1283
1284 static int __init slip_init(void)
1285 {
1286 int status;
1287
1288 if (slip_maxdev < 4)
1289 slip_maxdev = 4; /* Sanity */
1290
1291 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"
1292 #ifdef CONFIG_SLIP_MODE_SLIP6
1293 " (6 bit encapsulation enabled)"
1294 #endif
1295 ".\n",
1296 SLIP_VERSION, slip_maxdev);
1297 #if defined(SL_INCLUDE_CSLIP)
1298 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");
1299 #endif
1300 #ifdef CONFIG_SLIP_SMART
1301 printk(KERN_INFO "SLIP linefill/keepalive option.\n");
1302 #endif
1303
1304 slip_devs = kzalloc_objs(struct net_device *, slip_maxdev);
1305 if (!slip_devs)
1306 return -ENOMEM;
1307
1308 /* Fill in our line protocol discipline, and register it */
1309 status = tty_register_ldisc(&sl_ldisc);
1310 if (status != 0) {
1311 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);
1312 kfree(slip_devs);
1313 }
1314 return status;
1315 }
1316
1317 static void __exit slip_exit(void)
1318 {
1319 int i;
1320 struct net_device *dev;
1321 struct slip *sl;
1322 unsigned long timeout = jiffies + HZ;
1323 int busy = 0;
1324
1325 if (slip_devs == NULL)
1326 return;
1327
1328 /* First of all: check for active disciplines and hangup them.
1329 */
1330 do {
1331 if (busy)
1332 msleep_interruptible(100);
1333
1334 busy = 0;
1335 for (i = 0; i < slip_maxdev; i++) {
1336 dev = slip_devs[i];
1337 if (!dev)
1338 continue;
1339 sl = netdev_priv(dev);
1340 spin_lock_bh(&sl->lock);
1341 if (sl->tty) {
1342 busy++;
1343 tty_hangup(sl->tty);
1344 }
1345 spin_unlock_bh(&sl->lock);
1346 }
1347 } while (busy && time_before(jiffies, timeout));
1348
1349 /* FIXME: hangup is async so we should wait when doing this second
1350 phase */
1351
1352 for (i = 0; i < slip_maxdev; i++) {
1353 dev = slip_devs[i];
1354 if (!dev)
1355 continue;
1356 slip_devs[i] = NULL;
1357
1358 sl = netdev_priv(dev);
1359 if (sl->tty) {
1360 printk(KERN_ERR "%s: tty discipline still running\n",
1361 dev->name);
1362 }
1363
1364 unregister_netdev(dev);
1365 }
1366
1367 kfree(slip_devs);
1368 slip_devs = NULL;
1369
1370 tty_unregister_ldisc(&sl_ldisc);
1371 }
1372
1373 module_init(slip_init);
1374 module_exit(slip_exit);
1375
1376 #ifdef CONFIG_SLIP_SMART
1377 /*
1378 * This is start of the code for multislip style line checking
1379 * added by Stanislav Voronyi. All changes before marked VSV
1380 */
1381
1382 static void sl_outfill(struct timer_list *t)
1383 {
1384 struct slip *sl = timer_container_of(sl, t, outfill_timer);
1385
1386 spin_lock(&sl->lock);
1387
1388 if (sl->tty == NULL)
1389 goto out;
1390
1391 if (sl->outfill) {
1392 if (test_bit(SLF_OUTWAIT, &sl->flags)) {
1393 /* no packets were transmitted, do outfill */
1394 #ifdef CONFIG_SLIP_MODE_SLIP6
1395 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;
1396 #else
1397 unsigned char s = END;
1398 #endif
1399 /* put END into tty queue. Is it right ??? */
1400 if (!netif_queue_stopped(sl->dev)) {
1401 /* if device busy no outfill */
1402 sl->tty->ops->write(sl->tty, &s, 1);
1403 }
1404 } else
1405 set_bit(SLF_OUTWAIT, &sl->flags);
1406
1407 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);
1408 }
1409 out:
1410 spin_unlock(&sl->lock);
1411 }
1412
1413 static void sl_keepalive(struct timer_list *t)
1414 {
1415 struct slip *sl = timer_container_of(sl, t, keepalive_timer);
1416
1417 spin_lock(&sl->lock);
1418
1419 if (sl->tty == NULL)
1420 goto out;
1421
1422 if (sl->keepalive) {
1423 if (test_bit(SLF_KEEPTEST, &sl->flags)) {
1424 /* keepalive still high :(, we must hangup */
1425 if (sl->outfill)
1426 /* outfill timer must be deleted too */
1427 (void) timer_delete(&sl->outfill_timer);
1428 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name);
1429 /* this must hangup tty & close slip */
1430 tty_hangup(sl->tty);
1431 /* I think we need not something else */
1432 goto out;
1433 } else
1434 set_bit(SLF_KEEPTEST, &sl->flags);
1435
1436 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);
1437 }
1438 out:
1439 spin_unlock(&sl->lock);
1440 }
1441
1442 #endif
1443 MODULE_DESCRIPTION("SLIP (serial line) protocol module");
1444 MODULE_LICENSE("GPL");
1445 MODULE_ALIAS_LDISC(N_SLIP);
1446