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> | |
42 | #include <linux/if_ppp.h> | |
43 | #include <linux/ppp_channel.h> | |
44 | #include <linux/spinlock.h> | |
5e41fb83 | 45 | #include <linux/completion.h> |
1da177e4 | 46 | #include <linux/init.h> |
5a0e3ad6 | 47 | #include <linux/slab.h> |
1da177e4 | 48 | #include <asm/uaccess.h> |
1da177e4 LT |
49 | |
50 | #define PPP_VERSION "2.4.2" | |
51 | ||
52 | /* Structure for storing local state. */ | |
53 | struct syncppp { | |
54 | struct tty_struct *tty; | |
55 | unsigned int flags; | |
56 | unsigned int rbits; | |
57 | int mru; | |
58 | spinlock_t xmit_lock; | |
59 | spinlock_t recv_lock; | |
60 | unsigned long xmit_flags; | |
61 | u32 xaccm[8]; | |
62 | u32 raccm; | |
63 | unsigned int bytes_sent; | |
64 | unsigned int bytes_rcvd; | |
65 | ||
66 | struct sk_buff *tpkt; | |
67 | unsigned long last_xmit; | |
68 | ||
69 | struct sk_buff_head rqueue; | |
70 | ||
71 | struct tasklet_struct tsk; | |
72 | ||
73 | atomic_t refcnt; | |
5e41fb83 | 74 | struct completion dead_cmp; |
1da177e4 LT |
75 | struct ppp_channel chan; /* interface to generic ppp layer */ |
76 | }; | |
77 | ||
78 | /* Bit numbers in xmit_flags */ | |
79 | #define XMIT_WAKEUP 0 | |
80 | #define XMIT_FULL 1 | |
81 | ||
82 | /* Bits in rbits */ | |
83 | #define SC_RCV_BITS (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP) | |
84 | ||
85 | #define PPPSYNC_MAX_RQLEN 32 /* arbitrary */ | |
86 | ||
87 | /* | |
88 | * Prototypes. | |
89 | */ | |
90 | static struct sk_buff* ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *); | |
91 | static int ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb); | |
92 | static int ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd, | |
93 | unsigned long arg); | |
94 | static void ppp_sync_process(unsigned long arg); | |
95 | static int ppp_sync_push(struct syncppp *ap); | |
96 | static void ppp_sync_flush_output(struct syncppp *ap); | |
97 | static void ppp_sync_input(struct syncppp *ap, const unsigned char *buf, | |
98 | char *flags, int count); | |
99 | ||
d7100da0 | 100 | static const struct ppp_channel_ops sync_ops = { |
101 | .start_xmit = ppp_sync_send, | |
102 | .ioctl = ppp_sync_ioctl, | |
1da177e4 LT |
103 | }; |
104 | ||
105 | /* | |
106 | * Utility procedures to print a buffer in hex/ascii | |
107 | */ | |
108 | static void | |
109 | ppp_print_hex (register __u8 * out, const __u8 * in, int count) | |
110 | { | |
111 | register __u8 next_ch; | |
f71e1309 | 112 | static const char hex[] = "0123456789ABCDEF"; |
1da177e4 LT |
113 | |
114 | while (count-- > 0) { | |
115 | next_ch = *in++; | |
116 | *out++ = hex[(next_ch >> 4) & 0x0F]; | |
117 | *out++ = hex[next_ch & 0x0F]; | |
118 | ++out; | |
119 | } | |
120 | } | |
121 | ||
122 | static void | |
123 | ppp_print_char (register __u8 * out, const __u8 * in, int count) | |
124 | { | |
125 | register __u8 next_ch; | |
126 | ||
127 | while (count-- > 0) { | |
128 | next_ch = *in++; | |
129 | ||
130 | if (next_ch < 0x20 || next_ch > 0x7e) | |
131 | *out++ = '.'; | |
132 | else { | |
133 | *out++ = next_ch; | |
134 | if (next_ch == '%') /* printk/syslogd has a bug !! */ | |
135 | *out++ = '%'; | |
136 | } | |
137 | } | |
138 | *out = '\0'; | |
139 | } | |
140 | ||
141 | static void | |
142 | ppp_print_buffer (const char *name, const __u8 *buf, int count) | |
143 | { | |
144 | __u8 line[44]; | |
145 | ||
146 | if (name != NULL) | |
147 | printk(KERN_DEBUG "ppp_synctty: %s, count = %d\n", name, count); | |
148 | ||
149 | while (count > 8) { | |
150 | memset (line, 32, 44); | |
151 | ppp_print_hex (line, buf, 8); | |
152 | ppp_print_char (&line[8 * 3], buf, 8); | |
153 | printk(KERN_DEBUG "%s\n", line); | |
154 | count -= 8; | |
155 | buf += 8; | |
156 | } | |
157 | ||
158 | if (count > 0) { | |
159 | memset (line, 32, 44); | |
160 | ppp_print_hex (line, buf, count); | |
161 | ppp_print_char (&line[8 * 3], buf, count); | |
162 | printk(KERN_DEBUG "%s\n", line); | |
163 | } | |
164 | } | |
165 | ||
166 | ||
167 | /* | |
168 | * Routines implementing the synchronous PPP line discipline. | |
169 | */ | |
170 | ||
171 | /* | |
172 | * We have a potential race on dereferencing tty->disc_data, | |
173 | * because the tty layer provides no locking at all - thus one | |
174 | * cpu could be running ppp_synctty_receive while another | |
175 | * calls ppp_synctty_close, which zeroes tty->disc_data and | |
176 | * frees the memory that ppp_synctty_receive is using. The best | |
177 | * way to fix this is to use a rwlock in the tty struct, but for now | |
178 | * we use a single global rwlock for all ttys in ppp line discipline. | |
179 | * | |
180 | * FIXME: Fixed in tty_io nowdays. | |
181 | */ | |
182 | static DEFINE_RWLOCK(disc_data_lock); | |
183 | ||
184 | static struct syncppp *sp_get(struct tty_struct *tty) | |
185 | { | |
186 | struct syncppp *ap; | |
187 | ||
188 | read_lock(&disc_data_lock); | |
189 | ap = tty->disc_data; | |
190 | if (ap != NULL) | |
191 | atomic_inc(&ap->refcnt); | |
192 | read_unlock(&disc_data_lock); | |
193 | return ap; | |
194 | } | |
195 | ||
196 | static void sp_put(struct syncppp *ap) | |
197 | { | |
198 | if (atomic_dec_and_test(&ap->refcnt)) | |
5e41fb83 | 199 | complete(&ap->dead_cmp); |
1da177e4 LT |
200 | } |
201 | ||
202 | /* | |
203 | * Called when a tty is put into sync-PPP line discipline. | |
204 | */ | |
205 | static int | |
206 | ppp_sync_open(struct tty_struct *tty) | |
207 | { | |
208 | struct syncppp *ap; | |
209 | int err; | |
9c705260 | 210 | int speed; |
1da177e4 | 211 | |
f34d7a5b AC |
212 | if (tty->ops->write == NULL) |
213 | return -EOPNOTSUPP; | |
214 | ||
dd00cc48 | 215 | ap = kzalloc(sizeof(*ap), GFP_KERNEL); |
1da177e4 | 216 | err = -ENOMEM; |
cd228d54 | 217 | if (!ap) |
1da177e4 LT |
218 | goto out; |
219 | ||
220 | /* initialize the syncppp structure */ | |
1da177e4 LT |
221 | ap->tty = tty; |
222 | ap->mru = PPP_MRU; | |
223 | spin_lock_init(&ap->xmit_lock); | |
224 | spin_lock_init(&ap->recv_lock); | |
225 | ap->xaccm[0] = ~0U; | |
226 | ap->xaccm[3] = 0x60000000U; | |
227 | ap->raccm = ~0U; | |
228 | ||
229 | skb_queue_head_init(&ap->rqueue); | |
230 | tasklet_init(&ap->tsk, ppp_sync_process, (unsigned long) ap); | |
231 | ||
232 | atomic_set(&ap->refcnt, 1); | |
5e41fb83 | 233 | init_completion(&ap->dead_cmp); |
1da177e4 LT |
234 | |
235 | ap->chan.private = ap; | |
236 | ap->chan.ops = &sync_ops; | |
237 | ap->chan.mtu = PPP_MRU; | |
238 | ap->chan.hdrlen = 2; /* for A/C bytes */ | |
9c705260 GP |
239 | speed = tty_get_baud_rate(tty); |
240 | ap->chan.speed = speed; | |
1da177e4 LT |
241 | err = ppp_register_channel(&ap->chan); |
242 | if (err) | |
243 | goto out_free; | |
244 | ||
245 | tty->disc_data = ap; | |
33f0f88f | 246 | tty->receive_room = 65536; |
1da177e4 LT |
247 | return 0; |
248 | ||
249 | out_free: | |
250 | kfree(ap); | |
251 | out: | |
252 | return err; | |
253 | } | |
254 | ||
255 | /* | |
256 | * Called when the tty is put into another line discipline | |
257 | * or it hangs up. We have to wait for any cpu currently | |
258 | * executing in any of the other ppp_synctty_* routines to | |
259 | * finish before we can call ppp_unregister_channel and free | |
260 | * the syncppp struct. This routine must be called from | |
261 | * process context, not interrupt or softirq context. | |
262 | */ | |
263 | static void | |
264 | ppp_sync_close(struct tty_struct *tty) | |
265 | { | |
266 | struct syncppp *ap; | |
267 | ||
268 | write_lock_irq(&disc_data_lock); | |
269 | ap = tty->disc_data; | |
270 | tty->disc_data = NULL; | |
271 | write_unlock_irq(&disc_data_lock); | |
cd228d54 | 272 | if (!ap) |
1da177e4 LT |
273 | return; |
274 | ||
275 | /* | |
276 | * We have now ensured that nobody can start using ap from now | |
277 | * on, but we have to wait for all existing users to finish. | |
278 | * Note that ppp_unregister_channel ensures that no calls to | |
279 | * our channel ops (i.e. ppp_sync_send/ioctl) are in progress | |
280 | * by the time it returns. | |
281 | */ | |
282 | if (!atomic_dec_and_test(&ap->refcnt)) | |
5e41fb83 | 283 | wait_for_completion(&ap->dead_cmp); |
1da177e4 LT |
284 | tasklet_kill(&ap->tsk); |
285 | ||
286 | ppp_unregister_channel(&ap->chan); | |
287 | skb_queue_purge(&ap->rqueue); | |
1d2f8c95 | 288 | kfree_skb(ap->tpkt); |
1da177e4 LT |
289 | kfree(ap); |
290 | } | |
291 | ||
292 | /* | |
293 | * Called on tty hangup in process context. | |
294 | * | |
295 | * Wait for I/O to driver to complete and unregister PPP channel. | |
296 | * This is already done by the close routine, so just call that. | |
297 | */ | |
298 | static int ppp_sync_hangup(struct tty_struct *tty) | |
299 | { | |
300 | ppp_sync_close(tty); | |
301 | return 0; | |
302 | } | |
303 | ||
304 | /* | |
305 | * Read does nothing - no data is ever available this way. | |
306 | * Pppd reads and writes packets via /dev/ppp instead. | |
307 | */ | |
308 | static ssize_t | |
309 | ppp_sync_read(struct tty_struct *tty, struct file *file, | |
310 | unsigned char __user *buf, size_t count) | |
311 | { | |
312 | return -EAGAIN; | |
313 | } | |
314 | ||
315 | /* | |
316 | * Write on the tty does nothing, the packets all come in | |
317 | * from the ppp generic stuff. | |
318 | */ | |
319 | static ssize_t | |
320 | ppp_sync_write(struct tty_struct *tty, struct file *file, | |
321 | const unsigned char *buf, size_t count) | |
322 | { | |
323 | return -EAGAIN; | |
324 | } | |
325 | ||
326 | static int | |
327 | ppp_synctty_ioctl(struct tty_struct *tty, struct file *file, | |
328 | unsigned int cmd, unsigned long arg) | |
329 | { | |
330 | struct syncppp *ap = sp_get(tty); | |
331 | int __user *p = (int __user *)arg; | |
332 | int err, val; | |
333 | ||
cd228d54 | 334 | if (!ap) |
1da177e4 LT |
335 | return -ENXIO; |
336 | err = -EFAULT; | |
337 | switch (cmd) { | |
338 | case PPPIOCGCHAN: | |
1da177e4 LT |
339 | err = -EFAULT; |
340 | if (put_user(ppp_channel_index(&ap->chan), p)) | |
341 | break; | |
342 | err = 0; | |
343 | break; | |
344 | ||
345 | case PPPIOCGUNIT: | |
1da177e4 LT |
346 | err = -EFAULT; |
347 | if (put_user(ppp_unit_number(&ap->chan), p)) | |
348 | break; | |
349 | err = 0; | |
350 | break; | |
351 | ||
1da177e4 LT |
352 | case TCFLSH: |
353 | /* flush our buffers and the serial port's buffer */ | |
354 | if (arg == TCIOFLUSH || arg == TCOFLUSH) | |
355 | ppp_sync_flush_output(ap); | |
d0127539 | 356 | err = tty_perform_flush(tty, arg); |
1da177e4 LT |
357 | break; |
358 | ||
359 | case FIONREAD: | |
360 | val = 0; | |
361 | if (put_user(val, p)) | |
362 | break; | |
363 | err = 0; | |
364 | break; | |
365 | ||
366 | default: | |
d0127539 AC |
367 | err = tty_mode_ioctl(tty, file, cmd, arg); |
368 | break; | |
1da177e4 LT |
369 | } |
370 | ||
371 | sp_put(ap); | |
372 | return err; | |
373 | } | |
374 | ||
375 | /* No kernel lock - fine */ | |
376 | static unsigned int | |
377 | ppp_sync_poll(struct tty_struct *tty, struct file *file, poll_table *wait) | |
378 | { | |
379 | return 0; | |
380 | } | |
381 | ||
92d326f6 | 382 | /* May sleep, don't call from interrupt level or with interrupts disabled */ |
1da177e4 LT |
383 | static void |
384 | ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf, | |
385 | char *cflags, int count) | |
386 | { | |
387 | struct syncppp *ap = sp_get(tty); | |
388 | unsigned long flags; | |
389 | ||
cd228d54 | 390 | if (!ap) |
1da177e4 LT |
391 | return; |
392 | spin_lock_irqsave(&ap->recv_lock, flags); | |
393 | ppp_sync_input(ap, buf, cflags, count); | |
394 | spin_unlock_irqrestore(&ap->recv_lock, flags); | |
b03efcfb | 395 | if (!skb_queue_empty(&ap->rqueue)) |
1da177e4 LT |
396 | tasklet_schedule(&ap->tsk); |
397 | sp_put(ap); | |
4a21b8cb | 398 | tty_unthrottle(tty); |
1da177e4 LT |
399 | } |
400 | ||
401 | static void | |
402 | ppp_sync_wakeup(struct tty_struct *tty) | |
403 | { | |
404 | struct syncppp *ap = sp_get(tty); | |
405 | ||
406 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
cd228d54 | 407 | if (!ap) |
1da177e4 LT |
408 | return; |
409 | set_bit(XMIT_WAKEUP, &ap->xmit_flags); | |
410 | tasklet_schedule(&ap->tsk); | |
411 | sp_put(ap); | |
412 | } | |
413 | ||
414 | ||
a352def2 | 415 | static struct tty_ldisc_ops ppp_sync_ldisc = { |
1da177e4 LT |
416 | .owner = THIS_MODULE, |
417 | .magic = TTY_LDISC_MAGIC, | |
418 | .name = "pppsync", | |
419 | .open = ppp_sync_open, | |
420 | .close = ppp_sync_close, | |
421 | .hangup = ppp_sync_hangup, | |
422 | .read = ppp_sync_read, | |
423 | .write = ppp_sync_write, | |
424 | .ioctl = ppp_synctty_ioctl, | |
425 | .poll = ppp_sync_poll, | |
1da177e4 LT |
426 | .receive_buf = ppp_sync_receive, |
427 | .write_wakeup = ppp_sync_wakeup, | |
428 | }; | |
429 | ||
430 | static int __init | |
431 | ppp_sync_init(void) | |
432 | { | |
433 | int err; | |
434 | ||
435 | err = tty_register_ldisc(N_SYNC_PPP, &ppp_sync_ldisc); | |
436 | if (err != 0) | |
437 | printk(KERN_ERR "PPP_sync: error %d registering line disc.\n", | |
438 | err); | |
439 | return err; | |
440 | } | |
441 | ||
442 | /* | |
443 | * The following routines provide the PPP channel interface. | |
444 | */ | |
445 | static int | |
446 | ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd, unsigned long arg) | |
447 | { | |
448 | struct syncppp *ap = chan->private; | |
449 | int err, val; | |
450 | u32 accm[8]; | |
451 | void __user *argp = (void __user *)arg; | |
452 | u32 __user *p = argp; | |
453 | ||
454 | err = -EFAULT; | |
455 | switch (cmd) { | |
456 | case PPPIOCGFLAGS: | |
457 | val = ap->flags | ap->rbits; | |
458 | if (put_user(val, (int __user *) argp)) | |
459 | break; | |
460 | err = 0; | |
461 | break; | |
462 | case PPPIOCSFLAGS: | |
463 | if (get_user(val, (int __user *) argp)) | |
464 | break; | |
465 | ap->flags = val & ~SC_RCV_BITS; | |
466 | spin_lock_irq(&ap->recv_lock); | |
467 | ap->rbits = val & SC_RCV_BITS; | |
468 | spin_unlock_irq(&ap->recv_lock); | |
469 | err = 0; | |
470 | break; | |
471 | ||
472 | case PPPIOCGASYNCMAP: | |
473 | if (put_user(ap->xaccm[0], p)) | |
474 | break; | |
475 | err = 0; | |
476 | break; | |
477 | case PPPIOCSASYNCMAP: | |
478 | if (get_user(ap->xaccm[0], p)) | |
479 | break; | |
480 | err = 0; | |
481 | break; | |
482 | ||
483 | case PPPIOCGRASYNCMAP: | |
484 | if (put_user(ap->raccm, p)) | |
485 | break; | |
486 | err = 0; | |
487 | break; | |
488 | case PPPIOCSRASYNCMAP: | |
489 | if (get_user(ap->raccm, p)) | |
490 | break; | |
491 | err = 0; | |
492 | break; | |
493 | ||
494 | case PPPIOCGXASYNCMAP: | |
495 | if (copy_to_user(argp, ap->xaccm, sizeof(ap->xaccm))) | |
496 | break; | |
497 | err = 0; | |
498 | break; | |
499 | case PPPIOCSXASYNCMAP: | |
500 | if (copy_from_user(accm, argp, sizeof(accm))) | |
501 | break; | |
502 | accm[2] &= ~0x40000000U; /* can't escape 0x5e */ | |
503 | accm[3] |= 0x60000000U; /* must escape 0x7d, 0x7e */ | |
504 | memcpy(ap->xaccm, accm, sizeof(ap->xaccm)); | |
505 | err = 0; | |
506 | break; | |
507 | ||
508 | case PPPIOCGMRU: | |
509 | if (put_user(ap->mru, (int __user *) argp)) | |
510 | break; | |
511 | err = 0; | |
512 | break; | |
513 | case PPPIOCSMRU: | |
514 | if (get_user(val, (int __user *) argp)) | |
515 | break; | |
516 | if (val < PPP_MRU) | |
517 | val = PPP_MRU; | |
518 | ap->mru = val; | |
519 | err = 0; | |
520 | break; | |
521 | ||
522 | default: | |
523 | err = -ENOTTY; | |
524 | } | |
525 | return err; | |
526 | } | |
527 | ||
528 | /* | |
529 | * This is called at softirq level to deliver received packets | |
530 | * to the ppp_generic code, and to tell the ppp_generic code | |
531 | * if we can accept more output now. | |
532 | */ | |
533 | static void ppp_sync_process(unsigned long arg) | |
534 | { | |
535 | struct syncppp *ap = (struct syncppp *) arg; | |
536 | struct sk_buff *skb; | |
537 | ||
538 | /* process received packets */ | |
539 | while ((skb = skb_dequeue(&ap->rqueue)) != NULL) { | |
540 | if (skb->len == 0) { | |
541 | /* zero length buffers indicate error */ | |
542 | ppp_input_error(&ap->chan, 0); | |
543 | kfree_skb(skb); | |
544 | } | |
545 | else | |
546 | ppp_input(&ap->chan, skb); | |
547 | } | |
548 | ||
549 | /* try to push more stuff out */ | |
550 | if (test_bit(XMIT_WAKEUP, &ap->xmit_flags) && ppp_sync_push(ap)) | |
551 | ppp_output_wakeup(&ap->chan); | |
552 | } | |
553 | ||
554 | /* | |
555 | * Procedures for encapsulation and framing. | |
556 | */ | |
557 | ||
3c582b30 | 558 | static struct sk_buff* |
1da177e4 LT |
559 | ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *skb) |
560 | { | |
561 | int proto; | |
562 | unsigned char *data; | |
563 | int islcp; | |
564 | ||
565 | data = skb->data; | |
566 | proto = (data[0] << 8) + data[1]; | |
567 | ||
568 | /* LCP packets with codes between 1 (configure-request) | |
569 | * and 7 (code-reject) must be sent as though no options | |
570 | * have been negotiated. | |
571 | */ | |
572 | islcp = proto == PPP_LCP && 1 <= data[2] && data[2] <= 7; | |
573 | ||
574 | /* compress protocol field if option enabled */ | |
575 | if (data[0] == 0 && (ap->flags & SC_COMP_PROT) && !islcp) | |
576 | skb_pull(skb,1); | |
577 | ||
578 | /* prepend address/control fields if necessary */ | |
579 | if ((ap->flags & SC_COMP_AC) == 0 || islcp) { | |
580 | if (skb_headroom(skb) < 2) { | |
581 | struct sk_buff *npkt = dev_alloc_skb(skb->len + 2); | |
582 | if (npkt == NULL) { | |
583 | kfree_skb(skb); | |
584 | return NULL; | |
585 | } | |
586 | skb_reserve(npkt,2); | |
d626f62b ACM |
587 | skb_copy_from_linear_data(skb, |
588 | skb_put(npkt, skb->len), skb->len); | |
1da177e4 LT |
589 | kfree_skb(skb); |
590 | skb = npkt; | |
591 | } | |
592 | skb_push(skb,2); | |
593 | skb->data[0] = PPP_ALLSTATIONS; | |
594 | skb->data[1] = PPP_UI; | |
595 | } | |
596 | ||
597 | ap->last_xmit = jiffies; | |
598 | ||
599 | if (skb && ap->flags & SC_LOG_OUTPKT) | |
600 | ppp_print_buffer ("send buffer", skb->data, skb->len); | |
601 | ||
602 | return skb; | |
603 | } | |
604 | ||
605 | /* | |
606 | * Transmit-side routines. | |
607 | */ | |
608 | ||
609 | /* | |
610 | * Send a packet to the peer over an sync tty line. | |
611 | * Returns 1 iff the packet was accepted. | |
612 | * If the packet was not accepted, we will call ppp_output_wakeup | |
613 | * at some later time. | |
614 | */ | |
615 | static int | |
616 | ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb) | |
617 | { | |
618 | struct syncppp *ap = chan->private; | |
619 | ||
620 | ppp_sync_push(ap); | |
621 | ||
622 | if (test_and_set_bit(XMIT_FULL, &ap->xmit_flags)) | |
623 | return 0; /* already full */ | |
624 | skb = ppp_sync_txmunge(ap, skb); | |
625 | if (skb != NULL) | |
626 | ap->tpkt = skb; | |
627 | else | |
628 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
629 | ||
630 | ppp_sync_push(ap); | |
631 | return 1; | |
632 | } | |
633 | ||
634 | /* | |
635 | * Push as much data as possible out to the tty. | |
636 | */ | |
637 | static int | |
638 | ppp_sync_push(struct syncppp *ap) | |
639 | { | |
640 | int sent, done = 0; | |
641 | struct tty_struct *tty = ap->tty; | |
642 | int tty_stuffed = 0; | |
643 | ||
644 | if (!spin_trylock_bh(&ap->xmit_lock)) | |
645 | return 0; | |
646 | for (;;) { | |
647 | if (test_and_clear_bit(XMIT_WAKEUP, &ap->xmit_flags)) | |
648 | tty_stuffed = 0; | |
cd228d54 | 649 | if (!tty_stuffed && ap->tpkt) { |
1da177e4 | 650 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
f34d7a5b | 651 | sent = tty->ops->write(tty, ap->tpkt->data, ap->tpkt->len); |
1da177e4 LT |
652 | if (sent < 0) |
653 | goto flush; /* error, e.g. loss of CD */ | |
654 | if (sent < ap->tpkt->len) { | |
655 | tty_stuffed = 1; | |
656 | } else { | |
657 | kfree_skb(ap->tpkt); | |
658 | ap->tpkt = NULL; | |
659 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
660 | done = 1; | |
661 | } | |
662 | continue; | |
663 | } | |
664 | /* haven't made any progress */ | |
665 | spin_unlock_bh(&ap->xmit_lock); | |
8e95a202 JP |
666 | if (!(test_bit(XMIT_WAKEUP, &ap->xmit_flags) || |
667 | (!tty_stuffed && ap->tpkt))) | |
1da177e4 LT |
668 | break; |
669 | if (!spin_trylock_bh(&ap->xmit_lock)) | |
670 | break; | |
671 | } | |
672 | return done; | |
673 | ||
674 | flush: | |
cd228d54 | 675 | if (ap->tpkt) { |
1da177e4 LT |
676 | kfree_skb(ap->tpkt); |
677 | ap->tpkt = NULL; | |
678 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
679 | done = 1; | |
680 | } | |
681 | spin_unlock_bh(&ap->xmit_lock); | |
682 | return done; | |
683 | } | |
684 | ||
685 | /* | |
686 | * Flush output from our internal buffers. | |
687 | * Called for the TCFLSH ioctl. | |
688 | */ | |
689 | static void | |
690 | ppp_sync_flush_output(struct syncppp *ap) | |
691 | { | |
692 | int done = 0; | |
693 | ||
694 | spin_lock_bh(&ap->xmit_lock); | |
695 | if (ap->tpkt != NULL) { | |
696 | kfree_skb(ap->tpkt); | |
697 | ap->tpkt = NULL; | |
698 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
699 | done = 1; | |
700 | } | |
701 | spin_unlock_bh(&ap->xmit_lock); | |
702 | if (done) | |
703 | ppp_output_wakeup(&ap->chan); | |
704 | } | |
705 | ||
706 | /* | |
707 | * Receive-side routines. | |
708 | */ | |
709 | ||
710 | /* called when the tty driver has data for us. | |
711 | * | |
712 | * Data is frame oriented: each call to ppp_sync_input is considered | |
713 | * a whole frame. If the 1st flag byte is non-zero then the whole | |
714 | * frame is considered to be in error and is tossed. | |
715 | */ | |
716 | static void | |
717 | ppp_sync_input(struct syncppp *ap, const unsigned char *buf, | |
718 | char *flags, int count) | |
719 | { | |
720 | struct sk_buff *skb; | |
721 | unsigned char *p; | |
722 | ||
723 | if (count == 0) | |
724 | return; | |
725 | ||
726 | if (ap->flags & SC_LOG_INPKT) | |
727 | ppp_print_buffer ("receive buffer", buf, count); | |
728 | ||
729 | /* stuff the chars in the skb */ | |
cd228d54 JP |
730 | skb = dev_alloc_skb(ap->mru + PPP_HDRLEN + 2); |
731 | if (!skb) { | |
1da177e4 LT |
732 | printk(KERN_ERR "PPPsync: no memory (input pkt)\n"); |
733 | goto err; | |
734 | } | |
735 | /* Try to get the payload 4-byte aligned */ | |
736 | if (buf[0] != PPP_ALLSTATIONS) | |
737 | skb_reserve(skb, 2 + (buf[0] & 1)); | |
738 | ||
cd228d54 | 739 | if (flags && *flags) { |
1da177e4 LT |
740 | /* error flag set, ignore frame */ |
741 | goto err; | |
742 | } else if (count > skb_tailroom(skb)) { | |
743 | /* packet overflowed MRU */ | |
744 | goto err; | |
745 | } | |
746 | ||
747 | p = skb_put(skb, count); | |
748 | memcpy(p, buf, count); | |
749 | ||
750 | /* strip address/control field if present */ | |
751 | p = skb->data; | |
752 | if (p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) { | |
753 | /* chop off address/control */ | |
754 | if (skb->len < 3) | |
755 | goto err; | |
756 | p = skb_pull(skb, 2); | |
757 | } | |
758 | ||
759 | /* decompress protocol field if compressed */ | |
760 | if (p[0] & 1) { | |
761 | /* protocol is compressed */ | |
762 | skb_push(skb, 1)[0] = 0; | |
763 | } else if (skb->len < 2) | |
764 | goto err; | |
765 | ||
766 | /* queue the frame to be processed */ | |
767 | skb_queue_tail(&ap->rqueue, skb); | |
768 | return; | |
769 | ||
770 | err: | |
771 | /* queue zero length packet as error indication */ | |
772 | if (skb || (skb = dev_alloc_skb(0))) { | |
773 | skb_trim(skb, 0); | |
774 | skb_queue_tail(&ap->rqueue, skb); | |
775 | } | |
776 | } | |
777 | ||
778 | static void __exit | |
779 | ppp_sync_cleanup(void) | |
780 | { | |
64ccd715 | 781 | if (tty_unregister_ldisc(N_SYNC_PPP) != 0) |
1da177e4 LT |
782 | printk(KERN_ERR "failed to unregister Sync PPP line discipline\n"); |
783 | } | |
784 | ||
785 | module_init(ppp_sync_init); | |
786 | module_exit(ppp_sync_cleanup); | |
787 | MODULE_LICENSE("GPL"); | |
788 | MODULE_ALIAS_LDISC(N_SYNC_PPP); |