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31#include <linux/module.h>
32#include <linux/kernel.h>
33#include <linux/skbuff.h>
34#include <linux/tty.h>
35#include <linux/netdevice.h>
36#include <linux/poll.h>
37#include <linux/ppp_defs.h>
38#include <linux/ppp-ioctl.h>
39#include <linux/ppp_channel.h>
40#include <linux/spinlock.h>
41#include <linux/completion.h>
42#include <linux/init.h>
43#include <linux/interrupt.h>
44#include <linux/slab.h>
45#include <linux/refcount.h>
46#include <asm/unaligned.h>
47#include <linux/uaccess.h>
48
49#define PPP_VERSION "2.4.2"
50
51
52struct syncppp {
53 struct tty_struct *tty;
54 unsigned int flags;
55 unsigned int rbits;
56 int mru;
57 spinlock_t xmit_lock;
58 spinlock_t recv_lock;
59 unsigned long xmit_flags;
60 u32 xaccm[8];
61 u32 raccm;
62 unsigned int bytes_sent;
63 unsigned int bytes_rcvd;
64
65 struct sk_buff *tpkt;
66 unsigned long last_xmit;
67
68 struct sk_buff_head rqueue;
69
70 struct tasklet_struct tsk;
71
72 refcount_t refcnt;
73 struct completion dead_cmp;
74 struct ppp_channel chan;
75};
76
77
78#define XMIT_WAKEUP 0
79#define XMIT_FULL 1
80
81
82#define SC_RCV_BITS (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP)
83
84#define PPPSYNC_MAX_RQLEN 32
85
86
87
88
89static struct sk_buff* ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *);
90static int ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb);
91static int ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd,
92 unsigned long arg);
93static void ppp_sync_process(struct tasklet_struct *t);
94static int ppp_sync_push(struct syncppp *ap);
95static void ppp_sync_flush_output(struct syncppp *ap);
96static void ppp_sync_input(struct syncppp *ap, const unsigned char *buf,
97 const char *flags, int count);
98
99static const struct ppp_channel_ops sync_ops = {
100 .start_xmit = ppp_sync_send,
101 .ioctl = ppp_sync_ioctl,
102};
103
104
105
106
107static void
108ppp_print_buffer (const char *name, const __u8 *buf, int count)
109{
110 if (name != NULL)
111 printk(KERN_DEBUG "ppp_synctty: %s, count = %d\n", name, count);
112
113 print_hex_dump_bytes("", DUMP_PREFIX_NONE, buf, count);
114}
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132static DEFINE_RWLOCK(disc_data_lock);
133
134static struct syncppp *sp_get(struct tty_struct *tty)
135{
136 struct syncppp *ap;
137
138 read_lock(&disc_data_lock);
139 ap = tty->disc_data;
140 if (ap != NULL)
141 refcount_inc(&ap->refcnt);
142 read_unlock(&disc_data_lock);
143 return ap;
144}
145
146static void sp_put(struct syncppp *ap)
147{
148 if (refcount_dec_and_test(&ap->refcnt))
149 complete(&ap->dead_cmp);
150}
151
152
153
154
155static int
156ppp_sync_open(struct tty_struct *tty)
157{
158 struct syncppp *ap;
159 int err;
160 int speed;
161
162 if (tty->ops->write == NULL)
163 return -EOPNOTSUPP;
164
165 ap = kzalloc(sizeof(*ap), GFP_KERNEL);
166 err = -ENOMEM;
167 if (!ap)
168 goto out;
169
170
171 ap->tty = tty;
172 ap->mru = PPP_MRU;
173 spin_lock_init(&ap->xmit_lock);
174 spin_lock_init(&ap->recv_lock);
175 ap->xaccm[0] = ~0U;
176 ap->xaccm[3] = 0x60000000U;
177 ap->raccm = ~0U;
178
179 skb_queue_head_init(&ap->rqueue);
180 tasklet_setup(&ap->tsk, ppp_sync_process);
181
182 refcount_set(&ap->refcnt, 1);
183 init_completion(&ap->dead_cmp);
184
185 ap->chan.private = ap;
186 ap->chan.ops = &sync_ops;
187 ap->chan.mtu = PPP_MRU;
188 ap->chan.hdrlen = 2;
189 speed = tty_get_baud_rate(tty);
190 ap->chan.speed = speed;
191 err = ppp_register_channel(&ap->chan);
192 if (err)
193 goto out_free;
194
195 tty->disc_data = ap;
196 tty->receive_room = 65536;
197 return 0;
198
199 out_free:
200 kfree(ap);
201 out:
202 return err;
203}
204
205
206
207
208
209
210
211
212
213static void
214ppp_sync_close(struct tty_struct *tty)
215{
216 struct syncppp *ap;
217
218 write_lock_irq(&disc_data_lock);
219 ap = tty->disc_data;
220 tty->disc_data = NULL;
221 write_unlock_irq(&disc_data_lock);
222 if (!ap)
223 return;
224
225
226
227
228
229
230
231
232 if (!refcount_dec_and_test(&ap->refcnt))
233 wait_for_completion(&ap->dead_cmp);
234 tasklet_kill(&ap->tsk);
235
236 ppp_unregister_channel(&ap->chan);
237 skb_queue_purge(&ap->rqueue);
238 kfree_skb(ap->tpkt);
239 kfree(ap);
240}
241
242
243
244
245
246
247
248static int ppp_sync_hangup(struct tty_struct *tty)
249{
250 ppp_sync_close(tty);
251 return 0;
252}
253
254
255
256
257
258static ssize_t
259ppp_sync_read(struct tty_struct *tty, struct file *file,
260 unsigned char *buf, size_t count,
261 void **cookie, unsigned long offset)
262{
263 return -EAGAIN;
264}
265
266
267
268
269
270static ssize_t
271ppp_sync_write(struct tty_struct *tty, struct file *file,
272 const unsigned char *buf, size_t count)
273{
274 return -EAGAIN;
275}
276
277static int
278ppp_synctty_ioctl(struct tty_struct *tty, struct file *file,
279 unsigned int cmd, unsigned long arg)
280{
281 struct syncppp *ap = sp_get(tty);
282 int __user *p = (int __user *)arg;
283 int err, val;
284
285 if (!ap)
286 return -ENXIO;
287 err = -EFAULT;
288 switch (cmd) {
289 case PPPIOCGCHAN:
290 err = -EFAULT;
291 if (put_user(ppp_channel_index(&ap->chan), p))
292 break;
293 err = 0;
294 break;
295
296 case PPPIOCGUNIT:
297 err = -EFAULT;
298 if (put_user(ppp_unit_number(&ap->chan), p))
299 break;
300 err = 0;
301 break;
302
303 case TCFLSH:
304
305 if (arg == TCIOFLUSH || arg == TCOFLUSH)
306 ppp_sync_flush_output(ap);
307 err = n_tty_ioctl_helper(tty, file, cmd, arg);
308 break;
309
310 case FIONREAD:
311 val = 0;
312 if (put_user(val, p))
313 break;
314 err = 0;
315 break;
316
317 default:
318 err = tty_mode_ioctl(tty, file, cmd, arg);
319 break;
320 }
321
322 sp_put(ap);
323 return err;
324}
325
326
327static __poll_t
328ppp_sync_poll(struct tty_struct *tty, struct file *file, poll_table *wait)
329{
330 return 0;
331}
332
333
334static void
335ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf,
336 const char *cflags, int count)
337{
338 struct syncppp *ap = sp_get(tty);
339 unsigned long flags;
340
341 if (!ap)
342 return;
343 spin_lock_irqsave(&ap->recv_lock, flags);
344 ppp_sync_input(ap, buf, cflags, count);
345 spin_unlock_irqrestore(&ap->recv_lock, flags);
346 if (!skb_queue_empty(&ap->rqueue))
347 tasklet_schedule(&ap->tsk);
348 sp_put(ap);
349 tty_unthrottle(tty);
350}
351
352static void
353ppp_sync_wakeup(struct tty_struct *tty)
354{
355 struct syncppp *ap = sp_get(tty);
356
357 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
358 if (!ap)
359 return;
360 set_bit(XMIT_WAKEUP, &ap->xmit_flags);
361 tasklet_schedule(&ap->tsk);
362 sp_put(ap);
363}
364
365
366static struct tty_ldisc_ops ppp_sync_ldisc = {
367 .owner = THIS_MODULE,
368 .num = N_SYNC_PPP,
369 .name = "pppsync",
370 .open = ppp_sync_open,
371 .close = ppp_sync_close,
372 .hangup = ppp_sync_hangup,
373 .read = ppp_sync_read,
374 .write = ppp_sync_write,
375 .ioctl = ppp_synctty_ioctl,
376 .poll = ppp_sync_poll,
377 .receive_buf = ppp_sync_receive,
378 .write_wakeup = ppp_sync_wakeup,
379};
380
381static int __init
382ppp_sync_init(void)
383{
384 int err;
385
386 err = tty_register_ldisc(&ppp_sync_ldisc);
387 if (err != 0)
388 printk(KERN_ERR "PPP_sync: error %d registering line disc.\n",
389 err);
390 return err;
391}
392
393
394
395
396static int
397ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd, unsigned long arg)
398{
399 struct syncppp *ap = chan->private;
400 int err, val;
401 u32 accm[8];
402 void __user *argp = (void __user *)arg;
403 u32 __user *p = argp;
404
405 err = -EFAULT;
406 switch (cmd) {
407 case PPPIOCGFLAGS:
408 val = ap->flags | ap->rbits;
409 if (put_user(val, (int __user *) argp))
410 break;
411 err = 0;
412 break;
413 case PPPIOCSFLAGS:
414 if (get_user(val, (int __user *) argp))
415 break;
416 ap->flags = val & ~SC_RCV_BITS;
417 spin_lock_irq(&ap->recv_lock);
418 ap->rbits = val & SC_RCV_BITS;
419 spin_unlock_irq(&ap->recv_lock);
420 err = 0;
421 break;
422
423 case PPPIOCGASYNCMAP:
424 if (put_user(ap->xaccm[0], p))
425 break;
426 err = 0;
427 break;
428 case PPPIOCSASYNCMAP:
429 if (get_user(ap->xaccm[0], p))
430 break;
431 err = 0;
432 break;
433
434 case PPPIOCGRASYNCMAP:
435 if (put_user(ap->raccm, p))
436 break;
437 err = 0;
438 break;
439 case PPPIOCSRASYNCMAP:
440 if (get_user(ap->raccm, p))
441 break;
442 err = 0;
443 break;
444
445 case PPPIOCGXASYNCMAP:
446 if (copy_to_user(argp, ap->xaccm, sizeof(ap->xaccm)))
447 break;
448 err = 0;
449 break;
450 case PPPIOCSXASYNCMAP:
451 if (copy_from_user(accm, argp, sizeof(accm)))
452 break;
453 accm[2] &= ~0x40000000U;
454 accm[3] |= 0x60000000U;
455 memcpy(ap->xaccm, accm, sizeof(ap->xaccm));
456 err = 0;
457 break;
458
459 case PPPIOCGMRU:
460 if (put_user(ap->mru, (int __user *) argp))
461 break;
462 err = 0;
463 break;
464 case PPPIOCSMRU:
465 if (get_user(val, (int __user *) argp))
466 break;
467 if (val < PPP_MRU)
468 val = PPP_MRU;
469 ap->mru = val;
470 err = 0;
471 break;
472
473 default:
474 err = -ENOTTY;
475 }
476 return err;
477}
478
479
480
481
482
483
484static void ppp_sync_process(struct tasklet_struct *t)
485{
486 struct syncppp *ap = from_tasklet(ap, t, tsk);
487 struct sk_buff *skb;
488
489
490 while ((skb = skb_dequeue(&ap->rqueue)) != NULL) {
491 if (skb->len == 0) {
492
493 ppp_input_error(&ap->chan, 0);
494 kfree_skb(skb);
495 }
496 else
497 ppp_input(&ap->chan, skb);
498 }
499
500
501 if (test_bit(XMIT_WAKEUP, &ap->xmit_flags) && ppp_sync_push(ap))
502 ppp_output_wakeup(&ap->chan);
503}
504
505
506
507
508
509static struct sk_buff*
510ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *skb)
511{
512 int proto;
513 unsigned char *data;
514 int islcp;
515
516 data = skb->data;
517 proto = get_unaligned_be16(data);
518
519
520
521
522
523 islcp = proto == PPP_LCP && 1 <= data[2] && data[2] <= 7;
524
525
526 if (data[0] == 0 && (ap->flags & SC_COMP_PROT) && !islcp)
527 skb_pull(skb,1);
528
529
530 if ((ap->flags & SC_COMP_AC) == 0 || islcp) {
531 if (skb_headroom(skb) < 2) {
532 struct sk_buff *npkt = dev_alloc_skb(skb->len + 2);
533 if (npkt == NULL) {
534 kfree_skb(skb);
535 return NULL;
536 }
537 skb_reserve(npkt,2);
538 skb_copy_from_linear_data(skb,
539 skb_put(npkt, skb->len), skb->len);
540 consume_skb(skb);
541 skb = npkt;
542 }
543 skb_push(skb,2);
544 skb->data[0] = PPP_ALLSTATIONS;
545 skb->data[1] = PPP_UI;
546 }
547
548 ap->last_xmit = jiffies;
549
550 if (skb && ap->flags & SC_LOG_OUTPKT)
551 ppp_print_buffer ("send buffer", skb->data, skb->len);
552
553 return skb;
554}
555
556
557
558
559
560
561
562
563
564
565
566static int
567ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb)
568{
569 struct syncppp *ap = chan->private;
570
571 ppp_sync_push(ap);
572
573 if (test_and_set_bit(XMIT_FULL, &ap->xmit_flags))
574 return 0;
575 skb = ppp_sync_txmunge(ap, skb);
576 if (skb != NULL)
577 ap->tpkt = skb;
578 else
579 clear_bit(XMIT_FULL, &ap->xmit_flags);
580
581 ppp_sync_push(ap);
582 return 1;
583}
584
585
586
587
588static int
589ppp_sync_push(struct syncppp *ap)
590{
591 int sent, done = 0;
592 struct tty_struct *tty = ap->tty;
593 int tty_stuffed = 0;
594
595 if (!spin_trylock_bh(&ap->xmit_lock))
596 return 0;
597 for (;;) {
598 if (test_and_clear_bit(XMIT_WAKEUP, &ap->xmit_flags))
599 tty_stuffed = 0;
600 if (!tty_stuffed && ap->tpkt) {
601 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
602 sent = tty->ops->write(tty, ap->tpkt->data, ap->tpkt->len);
603 if (sent < 0)
604 goto flush;
605 if (sent < ap->tpkt->len) {
606 tty_stuffed = 1;
607 } else {
608 consume_skb(ap->tpkt);
609 ap->tpkt = NULL;
610 clear_bit(XMIT_FULL, &ap->xmit_flags);
611 done = 1;
612 }
613 continue;
614 }
615
616 spin_unlock_bh(&ap->xmit_lock);
617 if (!(test_bit(XMIT_WAKEUP, &ap->xmit_flags) ||
618 (!tty_stuffed && ap->tpkt)))
619 break;
620 if (!spin_trylock_bh(&ap->xmit_lock))
621 break;
622 }
623 return done;
624
625flush:
626 if (ap->tpkt) {
627 kfree_skb(ap->tpkt);
628 ap->tpkt = NULL;
629 clear_bit(XMIT_FULL, &ap->xmit_flags);
630 done = 1;
631 }
632 spin_unlock_bh(&ap->xmit_lock);
633 return done;
634}
635
636
637
638
639
640static void
641ppp_sync_flush_output(struct syncppp *ap)
642{
643 int done = 0;
644
645 spin_lock_bh(&ap->xmit_lock);
646 if (ap->tpkt != NULL) {
647 kfree_skb(ap->tpkt);
648 ap->tpkt = NULL;
649 clear_bit(XMIT_FULL, &ap->xmit_flags);
650 done = 1;
651 }
652 spin_unlock_bh(&ap->xmit_lock);
653 if (done)
654 ppp_output_wakeup(&ap->chan);
655}
656
657
658
659
660
661
662
663
664
665
666
667static void
668ppp_sync_input(struct syncppp *ap, const unsigned char *buf,
669 const char *flags, int count)
670{
671 struct sk_buff *skb;
672 unsigned char *p;
673
674 if (count == 0)
675 return;
676
677 if (ap->flags & SC_LOG_INPKT)
678 ppp_print_buffer ("receive buffer", buf, count);
679
680
681 skb = dev_alloc_skb(ap->mru + PPP_HDRLEN + 2);
682 if (!skb) {
683 printk(KERN_ERR "PPPsync: no memory (input pkt)\n");
684 goto err;
685 }
686
687 if (buf[0] != PPP_ALLSTATIONS)
688 skb_reserve(skb, 2 + (buf[0] & 1));
689
690 if (flags && *flags) {
691
692 goto err;
693 } else if (count > skb_tailroom(skb)) {
694
695 goto err;
696 }
697
698 skb_put_data(skb, buf, count);
699
700
701 p = skb->data;
702 if (p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
703
704 if (skb->len < 3)
705 goto err;
706 p = skb_pull(skb, 2);
707 }
708
709
710
711
712 if (!(p[0] & 0x01) && skb->len < 2)
713 goto err;
714
715
716 skb_queue_tail(&ap->rqueue, skb);
717 return;
718
719err:
720
721 if (skb || (skb = dev_alloc_skb(0))) {
722 skb_trim(skb, 0);
723 skb_queue_tail(&ap->rqueue, skb);
724 }
725}
726
727static void __exit
728ppp_sync_cleanup(void)
729{
730 tty_unregister_ldisc(&ppp_sync_ldisc);
731}
732
733module_init(ppp_sync_init);
734module_exit(ppp_sync_cleanup);
735MODULE_LICENSE("GPL");
736MODULE_ALIAS_LDISC(N_SYNC_PPP);
737