Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * PPP synchronous tty channel driver for Linux. | |
3 | * | |
4 | * This is a ppp channel driver that can be used with tty device drivers | |
5 | * that are frame oriented, such as synchronous HDLC devices. | |
6 | * | |
7 | * Complete PPP frames without encoding/decoding are exchanged between | |
8 | * the channel driver and the device driver. | |
6aa20a22 | 9 | * |
1da177e4 LT |
10 | * The async map IOCTL codes are implemented to keep the user mode |
11 | * applications happy if they call them. Synchronous PPP does not use | |
12 | * the async maps. | |
13 | * | |
14 | * Copyright 1999 Paul Mackerras. | |
15 | * | |
16 | * Also touched by the grubby hands of Paul Fulghum paulkf@microgate.com | |
17 | * | |
18 | * This program is free software; you can redistribute it and/or | |
19 | * modify it under the terms of the GNU General Public License | |
20 | * as published by the Free Software Foundation; either version | |
21 | * 2 of the License, or (at your option) any later version. | |
22 | * | |
23 | * This driver provides the encapsulation and framing for sending | |
24 | * and receiving PPP frames over sync serial lines. It relies on | |
25 | * the generic PPP layer to give it frames to send and to process | |
26 | * received frames. It implements the PPP line discipline. | |
27 | * | |
28 | * Part of the code in this driver was inspired by the old async-only | |
29 | * PPP driver, written by Michael Callahan and Al Longyear, and | |
30 | * subsequently hacked by Paul Mackerras. | |
31 | * | |
32 | * ==FILEVERSION 20040616== | |
33 | */ | |
34 | ||
35 | #include <linux/module.h> | |
36 | #include <linux/kernel.h> | |
37 | #include <linux/skbuff.h> | |
38 | #include <linux/tty.h> | |
39 | #include <linux/netdevice.h> | |
40 | #include <linux/poll.h> | |
41 | #include <linux/ppp_defs.h> | |
4b32da2b | 42 | #include <linux/ppp-ioctl.h> |
1da177e4 LT |
43 | #include <linux/ppp_channel.h> |
44 | #include <linux/spinlock.h> | |
5e41fb83 | 45 | #include <linux/completion.h> |
1da177e4 | 46 | #include <linux/init.h> |
a6b7a407 | 47 | #include <linux/interrupt.h> |
5a0e3ad6 | 48 | #include <linux/slab.h> |
96545aeb | 49 | #include <asm/unaligned.h> |
1da177e4 | 50 | #include <asm/uaccess.h> |
1da177e4 LT |
51 | |
52 | #define PPP_VERSION "2.4.2" | |
53 | ||
54 | /* Structure for storing local state. */ | |
55 | struct syncppp { | |
56 | struct tty_struct *tty; | |
57 | unsigned int flags; | |
58 | unsigned int rbits; | |
59 | int mru; | |
60 | spinlock_t xmit_lock; | |
61 | spinlock_t recv_lock; | |
62 | unsigned long xmit_flags; | |
63 | u32 xaccm[8]; | |
64 | u32 raccm; | |
65 | unsigned int bytes_sent; | |
66 | unsigned int bytes_rcvd; | |
67 | ||
68 | struct sk_buff *tpkt; | |
69 | unsigned long last_xmit; | |
70 | ||
71 | struct sk_buff_head rqueue; | |
72 | ||
73 | struct tasklet_struct tsk; | |
74 | ||
75 | atomic_t refcnt; | |
5e41fb83 | 76 | struct completion dead_cmp; |
1da177e4 LT |
77 | struct ppp_channel chan; /* interface to generic ppp layer */ |
78 | }; | |
79 | ||
80 | /* Bit numbers in xmit_flags */ | |
81 | #define XMIT_WAKEUP 0 | |
82 | #define XMIT_FULL 1 | |
83 | ||
84 | /* Bits in rbits */ | |
85 | #define SC_RCV_BITS (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP) | |
86 | ||
87 | #define PPPSYNC_MAX_RQLEN 32 /* arbitrary */ | |
88 | ||
89 | /* | |
90 | * Prototypes. | |
91 | */ | |
92 | static struct sk_buff* ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *); | |
93 | static int ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb); | |
94 | static int ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd, | |
95 | unsigned long arg); | |
96 | static void ppp_sync_process(unsigned long arg); | |
97 | static int ppp_sync_push(struct syncppp *ap); | |
98 | static void ppp_sync_flush_output(struct syncppp *ap); | |
99 | static void ppp_sync_input(struct syncppp *ap, const unsigned char *buf, | |
100 | char *flags, int count); | |
101 | ||
d7100da0 | 102 | static const struct ppp_channel_ops sync_ops = { |
103 | .start_xmit = ppp_sync_send, | |
104 | .ioctl = ppp_sync_ioctl, | |
1da177e4 LT |
105 | }; |
106 | ||
107 | /* | |
167bfa71 | 108 | * Utility procedure to print a buffer in hex/ascii |
1da177e4 | 109 | */ |
1da177e4 LT |
110 | static void |
111 | ppp_print_buffer (const char *name, const __u8 *buf, int count) | |
112 | { | |
1da177e4 LT |
113 | if (name != NULL) |
114 | printk(KERN_DEBUG "ppp_synctty: %s, count = %d\n", name, count); | |
115 | ||
167bfa71 | 116 | print_hex_dump_bytes("", DUMP_PREFIX_NONE, buf, count); |
1da177e4 LT |
117 | } |
118 | ||
119 | ||
120 | /* | |
121 | * Routines implementing the synchronous PPP line discipline. | |
122 | */ | |
123 | ||
124 | /* | |
125 | * We have a potential race on dereferencing tty->disc_data, | |
126 | * because the tty layer provides no locking at all - thus one | |
127 | * cpu could be running ppp_synctty_receive while another | |
128 | * calls ppp_synctty_close, which zeroes tty->disc_data and | |
129 | * frees the memory that ppp_synctty_receive is using. The best | |
130 | * way to fix this is to use a rwlock in the tty struct, but for now | |
131 | * we use a single global rwlock for all ttys in ppp line discipline. | |
132 | * | |
25985edc | 133 | * FIXME: Fixed in tty_io nowadays. |
1da177e4 LT |
134 | */ |
135 | static DEFINE_RWLOCK(disc_data_lock); | |
136 | ||
137 | static struct syncppp *sp_get(struct tty_struct *tty) | |
138 | { | |
139 | struct syncppp *ap; | |
140 | ||
141 | read_lock(&disc_data_lock); | |
142 | ap = tty->disc_data; | |
143 | if (ap != NULL) | |
144 | atomic_inc(&ap->refcnt); | |
145 | read_unlock(&disc_data_lock); | |
146 | return ap; | |
147 | } | |
148 | ||
149 | static void sp_put(struct syncppp *ap) | |
150 | { | |
151 | if (atomic_dec_and_test(&ap->refcnt)) | |
5e41fb83 | 152 | complete(&ap->dead_cmp); |
1da177e4 LT |
153 | } |
154 | ||
155 | /* | |
156 | * Called when a tty is put into sync-PPP line discipline. | |
157 | */ | |
158 | static int | |
159 | ppp_sync_open(struct tty_struct *tty) | |
160 | { | |
161 | struct syncppp *ap; | |
162 | int err; | |
9c705260 | 163 | int speed; |
1da177e4 | 164 | |
f34d7a5b AC |
165 | if (tty->ops->write == NULL) |
166 | return -EOPNOTSUPP; | |
167 | ||
dd00cc48 | 168 | ap = kzalloc(sizeof(*ap), GFP_KERNEL); |
1da177e4 | 169 | err = -ENOMEM; |
cd228d54 | 170 | if (!ap) |
1da177e4 LT |
171 | goto out; |
172 | ||
173 | /* initialize the syncppp structure */ | |
1da177e4 LT |
174 | ap->tty = tty; |
175 | ap->mru = PPP_MRU; | |
176 | spin_lock_init(&ap->xmit_lock); | |
177 | spin_lock_init(&ap->recv_lock); | |
178 | ap->xaccm[0] = ~0U; | |
179 | ap->xaccm[3] = 0x60000000U; | |
180 | ap->raccm = ~0U; | |
181 | ||
182 | skb_queue_head_init(&ap->rqueue); | |
183 | tasklet_init(&ap->tsk, ppp_sync_process, (unsigned long) ap); | |
184 | ||
185 | atomic_set(&ap->refcnt, 1); | |
5e41fb83 | 186 | init_completion(&ap->dead_cmp); |
1da177e4 LT |
187 | |
188 | ap->chan.private = ap; | |
189 | ap->chan.ops = &sync_ops; | |
190 | ap->chan.mtu = PPP_MRU; | |
191 | ap->chan.hdrlen = 2; /* for A/C bytes */ | |
9c705260 GP |
192 | speed = tty_get_baud_rate(tty); |
193 | ap->chan.speed = speed; | |
1da177e4 LT |
194 | err = ppp_register_channel(&ap->chan); |
195 | if (err) | |
196 | goto out_free; | |
197 | ||
198 | tty->disc_data = ap; | |
33f0f88f | 199 | tty->receive_room = 65536; |
1da177e4 LT |
200 | return 0; |
201 | ||
202 | out_free: | |
203 | kfree(ap); | |
204 | out: | |
205 | return err; | |
206 | } | |
207 | ||
208 | /* | |
209 | * Called when the tty is put into another line discipline | |
210 | * or it hangs up. We have to wait for any cpu currently | |
211 | * executing in any of the other ppp_synctty_* routines to | |
212 | * finish before we can call ppp_unregister_channel and free | |
213 | * the syncppp struct. This routine must be called from | |
214 | * process context, not interrupt or softirq context. | |
215 | */ | |
216 | static void | |
217 | ppp_sync_close(struct tty_struct *tty) | |
218 | { | |
219 | struct syncppp *ap; | |
220 | ||
221 | write_lock_irq(&disc_data_lock); | |
222 | ap = tty->disc_data; | |
223 | tty->disc_data = NULL; | |
224 | write_unlock_irq(&disc_data_lock); | |
cd228d54 | 225 | if (!ap) |
1da177e4 LT |
226 | return; |
227 | ||
228 | /* | |
229 | * We have now ensured that nobody can start using ap from now | |
230 | * on, but we have to wait for all existing users to finish. | |
231 | * Note that ppp_unregister_channel ensures that no calls to | |
232 | * our channel ops (i.e. ppp_sync_send/ioctl) are in progress | |
233 | * by the time it returns. | |
234 | */ | |
235 | if (!atomic_dec_and_test(&ap->refcnt)) | |
5e41fb83 | 236 | wait_for_completion(&ap->dead_cmp); |
1da177e4 LT |
237 | tasklet_kill(&ap->tsk); |
238 | ||
239 | ppp_unregister_channel(&ap->chan); | |
240 | skb_queue_purge(&ap->rqueue); | |
1d2f8c95 | 241 | kfree_skb(ap->tpkt); |
1da177e4 LT |
242 | kfree(ap); |
243 | } | |
244 | ||
245 | /* | |
246 | * Called on tty hangup in process context. | |
247 | * | |
248 | * Wait for I/O to driver to complete and unregister PPP channel. | |
249 | * This is already done by the close routine, so just call that. | |
250 | */ | |
251 | static int ppp_sync_hangup(struct tty_struct *tty) | |
252 | { | |
253 | ppp_sync_close(tty); | |
254 | return 0; | |
255 | } | |
256 | ||
257 | /* | |
258 | * Read does nothing - no data is ever available this way. | |
259 | * Pppd reads and writes packets via /dev/ppp instead. | |
260 | */ | |
261 | static ssize_t | |
262 | ppp_sync_read(struct tty_struct *tty, struct file *file, | |
263 | unsigned char __user *buf, size_t count) | |
264 | { | |
265 | return -EAGAIN; | |
266 | } | |
267 | ||
268 | /* | |
269 | * Write on the tty does nothing, the packets all come in | |
270 | * from the ppp generic stuff. | |
271 | */ | |
272 | static ssize_t | |
273 | ppp_sync_write(struct tty_struct *tty, struct file *file, | |
274 | const unsigned char *buf, size_t count) | |
275 | { | |
276 | return -EAGAIN; | |
277 | } | |
278 | ||
279 | static int | |
280 | ppp_synctty_ioctl(struct tty_struct *tty, struct file *file, | |
281 | unsigned int cmd, unsigned long arg) | |
282 | { | |
283 | struct syncppp *ap = sp_get(tty); | |
284 | int __user *p = (int __user *)arg; | |
285 | int err, val; | |
286 | ||
cd228d54 | 287 | if (!ap) |
1da177e4 LT |
288 | return -ENXIO; |
289 | err = -EFAULT; | |
290 | switch (cmd) { | |
291 | case PPPIOCGCHAN: | |
1da177e4 LT |
292 | err = -EFAULT; |
293 | if (put_user(ppp_channel_index(&ap->chan), p)) | |
294 | break; | |
295 | err = 0; | |
296 | break; | |
297 | ||
298 | case PPPIOCGUNIT: | |
1da177e4 LT |
299 | err = -EFAULT; |
300 | if (put_user(ppp_unit_number(&ap->chan), p)) | |
301 | break; | |
302 | err = 0; | |
303 | break; | |
304 | ||
1da177e4 LT |
305 | case TCFLSH: |
306 | /* flush our buffers and the serial port's buffer */ | |
307 | if (arg == TCIOFLUSH || arg == TCOFLUSH) | |
308 | ppp_sync_flush_output(ap); | |
e7f3880c | 309 | err = n_tty_ioctl_helper(tty, file, cmd, arg); |
1da177e4 LT |
310 | break; |
311 | ||
312 | case FIONREAD: | |
313 | val = 0; | |
314 | if (put_user(val, p)) | |
315 | break; | |
316 | err = 0; | |
317 | break; | |
318 | ||
319 | default: | |
d0127539 AC |
320 | err = tty_mode_ioctl(tty, file, cmd, arg); |
321 | break; | |
1da177e4 LT |
322 | } |
323 | ||
324 | sp_put(ap); | |
325 | return err; | |
326 | } | |
327 | ||
328 | /* No kernel lock - fine */ | |
329 | static unsigned int | |
330 | ppp_sync_poll(struct tty_struct *tty, struct file *file, poll_table *wait) | |
331 | { | |
332 | return 0; | |
333 | } | |
334 | ||
92d326f6 | 335 | /* May sleep, don't call from interrupt level or with interrupts disabled */ |
55db4c64 | 336 | static void |
1da177e4 LT |
337 | ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf, |
338 | char *cflags, int count) | |
339 | { | |
340 | struct syncppp *ap = sp_get(tty); | |
341 | unsigned long flags; | |
342 | ||
cd228d54 | 343 | if (!ap) |
55db4c64 | 344 | return; |
1da177e4 LT |
345 | spin_lock_irqsave(&ap->recv_lock, flags); |
346 | ppp_sync_input(ap, buf, cflags, count); | |
347 | spin_unlock_irqrestore(&ap->recv_lock, flags); | |
b03efcfb | 348 | if (!skb_queue_empty(&ap->rqueue)) |
1da177e4 LT |
349 | tasklet_schedule(&ap->tsk); |
350 | sp_put(ap); | |
4a21b8cb | 351 | tty_unthrottle(tty); |
1da177e4 LT |
352 | } |
353 | ||
354 | static void | |
355 | ppp_sync_wakeup(struct tty_struct *tty) | |
356 | { | |
357 | struct syncppp *ap = sp_get(tty); | |
358 | ||
359 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
cd228d54 | 360 | if (!ap) |
1da177e4 LT |
361 | return; |
362 | set_bit(XMIT_WAKEUP, &ap->xmit_flags); | |
363 | tasklet_schedule(&ap->tsk); | |
364 | sp_put(ap); | |
365 | } | |
366 | ||
367 | ||
a352def2 | 368 | static struct tty_ldisc_ops ppp_sync_ldisc = { |
1da177e4 LT |
369 | .owner = THIS_MODULE, |
370 | .magic = TTY_LDISC_MAGIC, | |
371 | .name = "pppsync", | |
372 | .open = ppp_sync_open, | |
373 | .close = ppp_sync_close, | |
374 | .hangup = ppp_sync_hangup, | |
375 | .read = ppp_sync_read, | |
376 | .write = ppp_sync_write, | |
377 | .ioctl = ppp_synctty_ioctl, | |
378 | .poll = ppp_sync_poll, | |
1da177e4 LT |
379 | .receive_buf = ppp_sync_receive, |
380 | .write_wakeup = ppp_sync_wakeup, | |
381 | }; | |
382 | ||
383 | static int __init | |
384 | ppp_sync_init(void) | |
385 | { | |
386 | int err; | |
387 | ||
388 | err = tty_register_ldisc(N_SYNC_PPP, &ppp_sync_ldisc); | |
389 | if (err != 0) | |
390 | printk(KERN_ERR "PPP_sync: error %d registering line disc.\n", | |
391 | err); | |
392 | return err; | |
393 | } | |
394 | ||
395 | /* | |
396 | * The following routines provide the PPP channel interface. | |
397 | */ | |
398 | static int | |
399 | ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd, unsigned long arg) | |
400 | { | |
401 | struct syncppp *ap = chan->private; | |
402 | int err, val; | |
403 | u32 accm[8]; | |
404 | void __user *argp = (void __user *)arg; | |
405 | u32 __user *p = argp; | |
406 | ||
407 | err = -EFAULT; | |
408 | switch (cmd) { | |
409 | case PPPIOCGFLAGS: | |
410 | val = ap->flags | ap->rbits; | |
411 | if (put_user(val, (int __user *) argp)) | |
412 | break; | |
413 | err = 0; | |
414 | break; | |
415 | case PPPIOCSFLAGS: | |
416 | if (get_user(val, (int __user *) argp)) | |
417 | break; | |
418 | ap->flags = val & ~SC_RCV_BITS; | |
419 | spin_lock_irq(&ap->recv_lock); | |
420 | ap->rbits = val & SC_RCV_BITS; | |
421 | spin_unlock_irq(&ap->recv_lock); | |
422 | err = 0; | |
423 | break; | |
424 | ||
425 | case PPPIOCGASYNCMAP: | |
426 | if (put_user(ap->xaccm[0], p)) | |
427 | break; | |
428 | err = 0; | |
429 | break; | |
430 | case PPPIOCSASYNCMAP: | |
431 | if (get_user(ap->xaccm[0], p)) | |
432 | break; | |
433 | err = 0; | |
434 | break; | |
435 | ||
436 | case PPPIOCGRASYNCMAP: | |
437 | if (put_user(ap->raccm, p)) | |
438 | break; | |
439 | err = 0; | |
440 | break; | |
441 | case PPPIOCSRASYNCMAP: | |
442 | if (get_user(ap->raccm, p)) | |
443 | break; | |
444 | err = 0; | |
445 | break; | |
446 | ||
447 | case PPPIOCGXASYNCMAP: | |
448 | if (copy_to_user(argp, ap->xaccm, sizeof(ap->xaccm))) | |
449 | break; | |
450 | err = 0; | |
451 | break; | |
452 | case PPPIOCSXASYNCMAP: | |
453 | if (copy_from_user(accm, argp, sizeof(accm))) | |
454 | break; | |
455 | accm[2] &= ~0x40000000U; /* can't escape 0x5e */ | |
456 | accm[3] |= 0x60000000U; /* must escape 0x7d, 0x7e */ | |
457 | memcpy(ap->xaccm, accm, sizeof(ap->xaccm)); | |
458 | err = 0; | |
459 | break; | |
460 | ||
461 | case PPPIOCGMRU: | |
462 | if (put_user(ap->mru, (int __user *) argp)) | |
463 | break; | |
464 | err = 0; | |
465 | break; | |
466 | case PPPIOCSMRU: | |
467 | if (get_user(val, (int __user *) argp)) | |
468 | break; | |
469 | if (val < PPP_MRU) | |
470 | val = PPP_MRU; | |
471 | ap->mru = val; | |
472 | err = 0; | |
473 | break; | |
474 | ||
475 | default: | |
476 | err = -ENOTTY; | |
477 | } | |
478 | return err; | |
479 | } | |
480 | ||
481 | /* | |
482 | * This is called at softirq level to deliver received packets | |
483 | * to the ppp_generic code, and to tell the ppp_generic code | |
484 | * if we can accept more output now. | |
485 | */ | |
486 | static void ppp_sync_process(unsigned long arg) | |
487 | { | |
488 | struct syncppp *ap = (struct syncppp *) arg; | |
489 | struct sk_buff *skb; | |
490 | ||
491 | /* process received packets */ | |
492 | while ((skb = skb_dequeue(&ap->rqueue)) != NULL) { | |
493 | if (skb->len == 0) { | |
494 | /* zero length buffers indicate error */ | |
495 | ppp_input_error(&ap->chan, 0); | |
496 | kfree_skb(skb); | |
497 | } | |
498 | else | |
499 | ppp_input(&ap->chan, skb); | |
500 | } | |
501 | ||
502 | /* try to push more stuff out */ | |
503 | if (test_bit(XMIT_WAKEUP, &ap->xmit_flags) && ppp_sync_push(ap)) | |
504 | ppp_output_wakeup(&ap->chan); | |
505 | } | |
506 | ||
507 | /* | |
508 | * Procedures for encapsulation and framing. | |
509 | */ | |
510 | ||
3c582b30 | 511 | static struct sk_buff* |
1da177e4 LT |
512 | ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *skb) |
513 | { | |
514 | int proto; | |
515 | unsigned char *data; | |
516 | int islcp; | |
517 | ||
518 | data = skb->data; | |
96545aeb | 519 | proto = get_unaligned_be16(data); |
1da177e4 LT |
520 | |
521 | /* LCP packets with codes between 1 (configure-request) | |
522 | * and 7 (code-reject) must be sent as though no options | |
523 | * have been negotiated. | |
524 | */ | |
525 | islcp = proto == PPP_LCP && 1 <= data[2] && data[2] <= 7; | |
526 | ||
527 | /* compress protocol field if option enabled */ | |
528 | if (data[0] == 0 && (ap->flags & SC_COMP_PROT) && !islcp) | |
529 | skb_pull(skb,1); | |
530 | ||
531 | /* prepend address/control fields if necessary */ | |
532 | if ((ap->flags & SC_COMP_AC) == 0 || islcp) { | |
533 | if (skb_headroom(skb) < 2) { | |
534 | struct sk_buff *npkt = dev_alloc_skb(skb->len + 2); | |
535 | if (npkt == NULL) { | |
536 | kfree_skb(skb); | |
537 | return NULL; | |
538 | } | |
539 | skb_reserve(npkt,2); | |
d626f62b ACM |
540 | skb_copy_from_linear_data(skb, |
541 | skb_put(npkt, skb->len), skb->len); | |
968d7018 | 542 | consume_skb(skb); |
1da177e4 LT |
543 | skb = npkt; |
544 | } | |
545 | skb_push(skb,2); | |
546 | skb->data[0] = PPP_ALLSTATIONS; | |
547 | skb->data[1] = PPP_UI; | |
548 | } | |
549 | ||
550 | ap->last_xmit = jiffies; | |
551 | ||
552 | if (skb && ap->flags & SC_LOG_OUTPKT) | |
553 | ppp_print_buffer ("send buffer", skb->data, skb->len); | |
554 | ||
555 | return skb; | |
556 | } | |
557 | ||
558 | /* | |
559 | * Transmit-side routines. | |
560 | */ | |
561 | ||
562 | /* | |
563 | * Send a packet to the peer over an sync tty line. | |
564 | * Returns 1 iff the packet was accepted. | |
565 | * If the packet was not accepted, we will call ppp_output_wakeup | |
566 | * at some later time. | |
567 | */ | |
568 | static int | |
569 | ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb) | |
570 | { | |
571 | struct syncppp *ap = chan->private; | |
572 | ||
573 | ppp_sync_push(ap); | |
574 | ||
575 | if (test_and_set_bit(XMIT_FULL, &ap->xmit_flags)) | |
576 | return 0; /* already full */ | |
577 | skb = ppp_sync_txmunge(ap, skb); | |
578 | if (skb != NULL) | |
579 | ap->tpkt = skb; | |
580 | else | |
581 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
582 | ||
583 | ppp_sync_push(ap); | |
584 | return 1; | |
585 | } | |
586 | ||
587 | /* | |
588 | * Push as much data as possible out to the tty. | |
589 | */ | |
590 | static int | |
591 | ppp_sync_push(struct syncppp *ap) | |
592 | { | |
593 | int sent, done = 0; | |
594 | struct tty_struct *tty = ap->tty; | |
595 | int tty_stuffed = 0; | |
596 | ||
597 | if (!spin_trylock_bh(&ap->xmit_lock)) | |
598 | return 0; | |
599 | for (;;) { | |
600 | if (test_and_clear_bit(XMIT_WAKEUP, &ap->xmit_flags)) | |
601 | tty_stuffed = 0; | |
cd228d54 | 602 | if (!tty_stuffed && ap->tpkt) { |
1da177e4 | 603 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
f34d7a5b | 604 | sent = tty->ops->write(tty, ap->tpkt->data, ap->tpkt->len); |
1da177e4 LT |
605 | if (sent < 0) |
606 | goto flush; /* error, e.g. loss of CD */ | |
607 | if (sent < ap->tpkt->len) { | |
608 | tty_stuffed = 1; | |
609 | } else { | |
968d7018 | 610 | consume_skb(ap->tpkt); |
1da177e4 LT |
611 | ap->tpkt = NULL; |
612 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
613 | done = 1; | |
614 | } | |
615 | continue; | |
616 | } | |
617 | /* haven't made any progress */ | |
618 | spin_unlock_bh(&ap->xmit_lock); | |
8e95a202 JP |
619 | if (!(test_bit(XMIT_WAKEUP, &ap->xmit_flags) || |
620 | (!tty_stuffed && ap->tpkt))) | |
1da177e4 LT |
621 | break; |
622 | if (!spin_trylock_bh(&ap->xmit_lock)) | |
623 | break; | |
624 | } | |
625 | return done; | |
626 | ||
627 | flush: | |
cd228d54 | 628 | if (ap->tpkt) { |
1da177e4 LT |
629 | kfree_skb(ap->tpkt); |
630 | ap->tpkt = NULL; | |
631 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
632 | done = 1; | |
633 | } | |
634 | spin_unlock_bh(&ap->xmit_lock); | |
635 | return done; | |
636 | } | |
637 | ||
638 | /* | |
639 | * Flush output from our internal buffers. | |
640 | * Called for the TCFLSH ioctl. | |
641 | */ | |
642 | static void | |
643 | ppp_sync_flush_output(struct syncppp *ap) | |
644 | { | |
645 | int done = 0; | |
646 | ||
647 | spin_lock_bh(&ap->xmit_lock); | |
648 | if (ap->tpkt != NULL) { | |
649 | kfree_skb(ap->tpkt); | |
650 | ap->tpkt = NULL; | |
651 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
652 | done = 1; | |
653 | } | |
654 | spin_unlock_bh(&ap->xmit_lock); | |
655 | if (done) | |
656 | ppp_output_wakeup(&ap->chan); | |
657 | } | |
658 | ||
659 | /* | |
660 | * Receive-side routines. | |
661 | */ | |
662 | ||
663 | /* called when the tty driver has data for us. | |
664 | * | |
665 | * Data is frame oriented: each call to ppp_sync_input is considered | |
666 | * a whole frame. If the 1st flag byte is non-zero then the whole | |
667 | * frame is considered to be in error and is tossed. | |
668 | */ | |
669 | static void | |
670 | ppp_sync_input(struct syncppp *ap, const unsigned char *buf, | |
671 | char *flags, int count) | |
672 | { | |
673 | struct sk_buff *skb; | |
674 | unsigned char *p; | |
675 | ||
676 | if (count == 0) | |
677 | return; | |
678 | ||
679 | if (ap->flags & SC_LOG_INPKT) | |
680 | ppp_print_buffer ("receive buffer", buf, count); | |
681 | ||
682 | /* stuff the chars in the skb */ | |
cd228d54 JP |
683 | skb = dev_alloc_skb(ap->mru + PPP_HDRLEN + 2); |
684 | if (!skb) { | |
1da177e4 LT |
685 | printk(KERN_ERR "PPPsync: no memory (input pkt)\n"); |
686 | goto err; | |
687 | } | |
688 | /* Try to get the payload 4-byte aligned */ | |
689 | if (buf[0] != PPP_ALLSTATIONS) | |
690 | skb_reserve(skb, 2 + (buf[0] & 1)); | |
691 | ||
cd228d54 | 692 | if (flags && *flags) { |
1da177e4 LT |
693 | /* error flag set, ignore frame */ |
694 | goto err; | |
695 | } else if (count > skb_tailroom(skb)) { | |
696 | /* packet overflowed MRU */ | |
697 | goto err; | |
698 | } | |
699 | ||
700 | p = skb_put(skb, count); | |
701 | memcpy(p, buf, count); | |
702 | ||
703 | /* strip address/control field if present */ | |
704 | p = skb->data; | |
705 | if (p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) { | |
706 | /* chop off address/control */ | |
707 | if (skb->len < 3) | |
708 | goto err; | |
709 | p = skb_pull(skb, 2); | |
710 | } | |
711 | ||
712 | /* decompress protocol field if compressed */ | |
713 | if (p[0] & 1) { | |
714 | /* protocol is compressed */ | |
715 | skb_push(skb, 1)[0] = 0; | |
716 | } else if (skb->len < 2) | |
717 | goto err; | |
718 | ||
719 | /* queue the frame to be processed */ | |
720 | skb_queue_tail(&ap->rqueue, skb); | |
721 | return; | |
722 | ||
723 | err: | |
724 | /* queue zero length packet as error indication */ | |
725 | if (skb || (skb = dev_alloc_skb(0))) { | |
726 | skb_trim(skb, 0); | |
727 | skb_queue_tail(&ap->rqueue, skb); | |
728 | } | |
729 | } | |
730 | ||
731 | static void __exit | |
732 | ppp_sync_cleanup(void) | |
733 | { | |
64ccd715 | 734 | if (tty_unregister_ldisc(N_SYNC_PPP) != 0) |
1da177e4 LT |
735 | printk(KERN_ERR "failed to unregister Sync PPP line discipline\n"); |
736 | } | |
737 | ||
738 | module_init(ppp_sync_init); | |
739 | module_exit(ppp_sync_cleanup); | |
740 | MODULE_LICENSE("GPL"); | |
741 | MODULE_ALIAS_LDISC(N_SYNC_PPP); |