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> |
96545aeb | 48 | #include <asm/unaligned.h> |
1da177e4 | 49 | #include <asm/uaccess.h> |
1da177e4 LT |
50 | |
51 | #define PPP_VERSION "2.4.2" | |
52 | ||
53 | /* Structure for storing local state. */ | |
54 | struct syncppp { | |
55 | struct tty_struct *tty; | |
56 | unsigned int flags; | |
57 | unsigned int rbits; | |
58 | int mru; | |
59 | spinlock_t xmit_lock; | |
60 | spinlock_t recv_lock; | |
61 | unsigned long xmit_flags; | |
62 | u32 xaccm[8]; | |
63 | u32 raccm; | |
64 | unsigned int bytes_sent; | |
65 | unsigned int bytes_rcvd; | |
66 | ||
67 | struct sk_buff *tpkt; | |
68 | unsigned long last_xmit; | |
69 | ||
70 | struct sk_buff_head rqueue; | |
71 | ||
72 | struct tasklet_struct tsk; | |
73 | ||
74 | atomic_t refcnt; | |
5e41fb83 | 75 | struct completion dead_cmp; |
1da177e4 LT |
76 | struct ppp_channel chan; /* interface to generic ppp layer */ |
77 | }; | |
78 | ||
79 | /* Bit numbers in xmit_flags */ | |
80 | #define XMIT_WAKEUP 0 | |
81 | #define XMIT_FULL 1 | |
82 | ||
83 | /* Bits in rbits */ | |
84 | #define SC_RCV_BITS (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP) | |
85 | ||
86 | #define PPPSYNC_MAX_RQLEN 32 /* arbitrary */ | |
87 | ||
88 | /* | |
89 | * Prototypes. | |
90 | */ | |
91 | static struct sk_buff* ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *); | |
92 | static int ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb); | |
93 | static int ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd, | |
94 | unsigned long arg); | |
95 | static void ppp_sync_process(unsigned long arg); | |
96 | static int ppp_sync_push(struct syncppp *ap); | |
97 | static void ppp_sync_flush_output(struct syncppp *ap); | |
98 | static void ppp_sync_input(struct syncppp *ap, const unsigned char *buf, | |
99 | char *flags, int count); | |
100 | ||
d7100da0 | 101 | static const struct ppp_channel_ops sync_ops = { |
102 | .start_xmit = ppp_sync_send, | |
103 | .ioctl = ppp_sync_ioctl, | |
1da177e4 LT |
104 | }; |
105 | ||
106 | /* | |
107 | * Utility procedures to print a buffer in hex/ascii | |
108 | */ | |
109 | static void | |
110 | ppp_print_hex (register __u8 * out, const __u8 * in, int count) | |
111 | { | |
112 | register __u8 next_ch; | |
f71e1309 | 113 | static const char hex[] = "0123456789ABCDEF"; |
1da177e4 LT |
114 | |
115 | while (count-- > 0) { | |
116 | next_ch = *in++; | |
117 | *out++ = hex[(next_ch >> 4) & 0x0F]; | |
118 | *out++ = hex[next_ch & 0x0F]; | |
119 | ++out; | |
120 | } | |
121 | } | |
122 | ||
123 | static void | |
124 | ppp_print_char (register __u8 * out, const __u8 * in, int count) | |
125 | { | |
126 | register __u8 next_ch; | |
127 | ||
128 | while (count-- > 0) { | |
129 | next_ch = *in++; | |
130 | ||
131 | if (next_ch < 0x20 || next_ch > 0x7e) | |
132 | *out++ = '.'; | |
133 | else { | |
134 | *out++ = next_ch; | |
135 | if (next_ch == '%') /* printk/syslogd has a bug !! */ | |
136 | *out++ = '%'; | |
137 | } | |
138 | } | |
139 | *out = '\0'; | |
140 | } | |
141 | ||
142 | static void | |
143 | ppp_print_buffer (const char *name, const __u8 *buf, int count) | |
144 | { | |
145 | __u8 line[44]; | |
146 | ||
147 | if (name != NULL) | |
148 | printk(KERN_DEBUG "ppp_synctty: %s, count = %d\n", name, count); | |
149 | ||
150 | while (count > 8) { | |
151 | memset (line, 32, 44); | |
152 | ppp_print_hex (line, buf, 8); | |
153 | ppp_print_char (&line[8 * 3], buf, 8); | |
154 | printk(KERN_DEBUG "%s\n", line); | |
155 | count -= 8; | |
156 | buf += 8; | |
157 | } | |
158 | ||
159 | if (count > 0) { | |
160 | memset (line, 32, 44); | |
161 | ppp_print_hex (line, buf, count); | |
162 | ppp_print_char (&line[8 * 3], buf, count); | |
163 | printk(KERN_DEBUG "%s\n", line); | |
164 | } | |
165 | } | |
166 | ||
167 | ||
168 | /* | |
169 | * Routines implementing the synchronous PPP line discipline. | |
170 | */ | |
171 | ||
172 | /* | |
173 | * We have a potential race on dereferencing tty->disc_data, | |
174 | * because the tty layer provides no locking at all - thus one | |
175 | * cpu could be running ppp_synctty_receive while another | |
176 | * calls ppp_synctty_close, which zeroes tty->disc_data and | |
177 | * frees the memory that ppp_synctty_receive is using. The best | |
178 | * way to fix this is to use a rwlock in the tty struct, but for now | |
179 | * we use a single global rwlock for all ttys in ppp line discipline. | |
180 | * | |
25985edc | 181 | * FIXME: Fixed in tty_io nowadays. |
1da177e4 LT |
182 | */ |
183 | static DEFINE_RWLOCK(disc_data_lock); | |
184 | ||
185 | static struct syncppp *sp_get(struct tty_struct *tty) | |
186 | { | |
187 | struct syncppp *ap; | |
188 | ||
189 | read_lock(&disc_data_lock); | |
190 | ap = tty->disc_data; | |
191 | if (ap != NULL) | |
192 | atomic_inc(&ap->refcnt); | |
193 | read_unlock(&disc_data_lock); | |
194 | return ap; | |
195 | } | |
196 | ||
197 | static void sp_put(struct syncppp *ap) | |
198 | { | |
199 | if (atomic_dec_and_test(&ap->refcnt)) | |
5e41fb83 | 200 | complete(&ap->dead_cmp); |
1da177e4 LT |
201 | } |
202 | ||
203 | /* | |
204 | * Called when a tty is put into sync-PPP line discipline. | |
205 | */ | |
206 | static int | |
207 | ppp_sync_open(struct tty_struct *tty) | |
208 | { | |
209 | struct syncppp *ap; | |
210 | int err; | |
9c705260 | 211 | int speed; |
1da177e4 | 212 | |
f34d7a5b AC |
213 | if (tty->ops->write == NULL) |
214 | return -EOPNOTSUPP; | |
215 | ||
dd00cc48 | 216 | ap = kzalloc(sizeof(*ap), GFP_KERNEL); |
1da177e4 | 217 | err = -ENOMEM; |
cd228d54 | 218 | if (!ap) |
1da177e4 LT |
219 | goto out; |
220 | ||
221 | /* initialize the syncppp structure */ | |
1da177e4 LT |
222 | ap->tty = tty; |
223 | ap->mru = PPP_MRU; | |
224 | spin_lock_init(&ap->xmit_lock); | |
225 | spin_lock_init(&ap->recv_lock); | |
226 | ap->xaccm[0] = ~0U; | |
227 | ap->xaccm[3] = 0x60000000U; | |
228 | ap->raccm = ~0U; | |
229 | ||
230 | skb_queue_head_init(&ap->rqueue); | |
231 | tasklet_init(&ap->tsk, ppp_sync_process, (unsigned long) ap); | |
232 | ||
233 | atomic_set(&ap->refcnt, 1); | |
5e41fb83 | 234 | init_completion(&ap->dead_cmp); |
1da177e4 LT |
235 | |
236 | ap->chan.private = ap; | |
237 | ap->chan.ops = &sync_ops; | |
238 | ap->chan.mtu = PPP_MRU; | |
239 | ap->chan.hdrlen = 2; /* for A/C bytes */ | |
9c705260 GP |
240 | speed = tty_get_baud_rate(tty); |
241 | ap->chan.speed = speed; | |
1da177e4 LT |
242 | err = ppp_register_channel(&ap->chan); |
243 | if (err) | |
244 | goto out_free; | |
245 | ||
246 | tty->disc_data = ap; | |
33f0f88f | 247 | tty->receive_room = 65536; |
1da177e4 LT |
248 | return 0; |
249 | ||
250 | out_free: | |
251 | kfree(ap); | |
252 | out: | |
253 | return err; | |
254 | } | |
255 | ||
256 | /* | |
257 | * Called when the tty is put into another line discipline | |
258 | * or it hangs up. We have to wait for any cpu currently | |
259 | * executing in any of the other ppp_synctty_* routines to | |
260 | * finish before we can call ppp_unregister_channel and free | |
261 | * the syncppp struct. This routine must be called from | |
262 | * process context, not interrupt or softirq context. | |
263 | */ | |
264 | static void | |
265 | ppp_sync_close(struct tty_struct *tty) | |
266 | { | |
267 | struct syncppp *ap; | |
268 | ||
269 | write_lock_irq(&disc_data_lock); | |
270 | ap = tty->disc_data; | |
271 | tty->disc_data = NULL; | |
272 | write_unlock_irq(&disc_data_lock); | |
cd228d54 | 273 | if (!ap) |
1da177e4 LT |
274 | return; |
275 | ||
276 | /* | |
277 | * We have now ensured that nobody can start using ap from now | |
278 | * on, but we have to wait for all existing users to finish. | |
279 | * Note that ppp_unregister_channel ensures that no calls to | |
280 | * our channel ops (i.e. ppp_sync_send/ioctl) are in progress | |
281 | * by the time it returns. | |
282 | */ | |
283 | if (!atomic_dec_and_test(&ap->refcnt)) | |
5e41fb83 | 284 | wait_for_completion(&ap->dead_cmp); |
1da177e4 LT |
285 | tasklet_kill(&ap->tsk); |
286 | ||
287 | ppp_unregister_channel(&ap->chan); | |
288 | skb_queue_purge(&ap->rqueue); | |
1d2f8c95 | 289 | kfree_skb(ap->tpkt); |
1da177e4 LT |
290 | kfree(ap); |
291 | } | |
292 | ||
293 | /* | |
294 | * Called on tty hangup in process context. | |
295 | * | |
296 | * Wait for I/O to driver to complete and unregister PPP channel. | |
297 | * This is already done by the close routine, so just call that. | |
298 | */ | |
299 | static int ppp_sync_hangup(struct tty_struct *tty) | |
300 | { | |
301 | ppp_sync_close(tty); | |
302 | return 0; | |
303 | } | |
304 | ||
305 | /* | |
306 | * Read does nothing - no data is ever available this way. | |
307 | * Pppd reads and writes packets via /dev/ppp instead. | |
308 | */ | |
309 | static ssize_t | |
310 | ppp_sync_read(struct tty_struct *tty, struct file *file, | |
311 | unsigned char __user *buf, size_t count) | |
312 | { | |
313 | return -EAGAIN; | |
314 | } | |
315 | ||
316 | /* | |
317 | * Write on the tty does nothing, the packets all come in | |
318 | * from the ppp generic stuff. | |
319 | */ | |
320 | static ssize_t | |
321 | ppp_sync_write(struct tty_struct *tty, struct file *file, | |
322 | const unsigned char *buf, size_t count) | |
323 | { | |
324 | return -EAGAIN; | |
325 | } | |
326 | ||
327 | static int | |
328 | ppp_synctty_ioctl(struct tty_struct *tty, struct file *file, | |
329 | unsigned int cmd, unsigned long arg) | |
330 | { | |
331 | struct syncppp *ap = sp_get(tty); | |
332 | int __user *p = (int __user *)arg; | |
333 | int err, val; | |
334 | ||
cd228d54 | 335 | if (!ap) |
1da177e4 LT |
336 | return -ENXIO; |
337 | err = -EFAULT; | |
338 | switch (cmd) { | |
339 | case PPPIOCGCHAN: | |
1da177e4 LT |
340 | err = -EFAULT; |
341 | if (put_user(ppp_channel_index(&ap->chan), p)) | |
342 | break; | |
343 | err = 0; | |
344 | break; | |
345 | ||
346 | case PPPIOCGUNIT: | |
1da177e4 LT |
347 | err = -EFAULT; |
348 | if (put_user(ppp_unit_number(&ap->chan), p)) | |
349 | break; | |
350 | err = 0; | |
351 | break; | |
352 | ||
1da177e4 LT |
353 | case TCFLSH: |
354 | /* flush our buffers and the serial port's buffer */ | |
355 | if (arg == TCIOFLUSH || arg == TCOFLUSH) | |
356 | ppp_sync_flush_output(ap); | |
d0127539 | 357 | err = tty_perform_flush(tty, arg); |
1da177e4 LT |
358 | break; |
359 | ||
360 | case FIONREAD: | |
361 | val = 0; | |
362 | if (put_user(val, p)) | |
363 | break; | |
364 | err = 0; | |
365 | break; | |
366 | ||
367 | default: | |
d0127539 AC |
368 | err = tty_mode_ioctl(tty, file, cmd, arg); |
369 | break; | |
1da177e4 LT |
370 | } |
371 | ||
372 | sp_put(ap); | |
373 | return err; | |
374 | } | |
375 | ||
376 | /* No kernel lock - fine */ | |
377 | static unsigned int | |
378 | ppp_sync_poll(struct tty_struct *tty, struct file *file, poll_table *wait) | |
379 | { | |
380 | return 0; | |
381 | } | |
382 | ||
92d326f6 | 383 | /* May sleep, don't call from interrupt level or with interrupts disabled */ |
1da177e4 LT |
384 | static void |
385 | ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf, | |
386 | char *cflags, int count) | |
387 | { | |
388 | struct syncppp *ap = sp_get(tty); | |
389 | unsigned long flags; | |
390 | ||
cd228d54 | 391 | if (!ap) |
1da177e4 LT |
392 | return; |
393 | spin_lock_irqsave(&ap->recv_lock, flags); | |
394 | ppp_sync_input(ap, buf, cflags, count); | |
395 | spin_unlock_irqrestore(&ap->recv_lock, flags); | |
b03efcfb | 396 | if (!skb_queue_empty(&ap->rqueue)) |
1da177e4 LT |
397 | tasklet_schedule(&ap->tsk); |
398 | sp_put(ap); | |
4a21b8cb | 399 | tty_unthrottle(tty); |
1da177e4 LT |
400 | } |
401 | ||
402 | static void | |
403 | ppp_sync_wakeup(struct tty_struct *tty) | |
404 | { | |
405 | struct syncppp *ap = sp_get(tty); | |
406 | ||
407 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
cd228d54 | 408 | if (!ap) |
1da177e4 LT |
409 | return; |
410 | set_bit(XMIT_WAKEUP, &ap->xmit_flags); | |
411 | tasklet_schedule(&ap->tsk); | |
412 | sp_put(ap); | |
413 | } | |
414 | ||
415 | ||
a352def2 | 416 | static struct tty_ldisc_ops ppp_sync_ldisc = { |
1da177e4 LT |
417 | .owner = THIS_MODULE, |
418 | .magic = TTY_LDISC_MAGIC, | |
419 | .name = "pppsync", | |
420 | .open = ppp_sync_open, | |
421 | .close = ppp_sync_close, | |
422 | .hangup = ppp_sync_hangup, | |
423 | .read = ppp_sync_read, | |
424 | .write = ppp_sync_write, | |
425 | .ioctl = ppp_synctty_ioctl, | |
426 | .poll = ppp_sync_poll, | |
1da177e4 LT |
427 | .receive_buf = ppp_sync_receive, |
428 | .write_wakeup = ppp_sync_wakeup, | |
429 | }; | |
430 | ||
431 | static int __init | |
432 | ppp_sync_init(void) | |
433 | { | |
434 | int err; | |
435 | ||
436 | err = tty_register_ldisc(N_SYNC_PPP, &ppp_sync_ldisc); | |
437 | if (err != 0) | |
438 | printk(KERN_ERR "PPP_sync: error %d registering line disc.\n", | |
439 | err); | |
440 | return err; | |
441 | } | |
442 | ||
443 | /* | |
444 | * The following routines provide the PPP channel interface. | |
445 | */ | |
446 | static int | |
447 | ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd, unsigned long arg) | |
448 | { | |
449 | struct syncppp *ap = chan->private; | |
450 | int err, val; | |
451 | u32 accm[8]; | |
452 | void __user *argp = (void __user *)arg; | |
453 | u32 __user *p = argp; | |
454 | ||
455 | err = -EFAULT; | |
456 | switch (cmd) { | |
457 | case PPPIOCGFLAGS: | |
458 | val = ap->flags | ap->rbits; | |
459 | if (put_user(val, (int __user *) argp)) | |
460 | break; | |
461 | err = 0; | |
462 | break; | |
463 | case PPPIOCSFLAGS: | |
464 | if (get_user(val, (int __user *) argp)) | |
465 | break; | |
466 | ap->flags = val & ~SC_RCV_BITS; | |
467 | spin_lock_irq(&ap->recv_lock); | |
468 | ap->rbits = val & SC_RCV_BITS; | |
469 | spin_unlock_irq(&ap->recv_lock); | |
470 | err = 0; | |
471 | break; | |
472 | ||
473 | case PPPIOCGASYNCMAP: | |
474 | if (put_user(ap->xaccm[0], p)) | |
475 | break; | |
476 | err = 0; | |
477 | break; | |
478 | case PPPIOCSASYNCMAP: | |
479 | if (get_user(ap->xaccm[0], p)) | |
480 | break; | |
481 | err = 0; | |
482 | break; | |
483 | ||
484 | case PPPIOCGRASYNCMAP: | |
485 | if (put_user(ap->raccm, p)) | |
486 | break; | |
487 | err = 0; | |
488 | break; | |
489 | case PPPIOCSRASYNCMAP: | |
490 | if (get_user(ap->raccm, p)) | |
491 | break; | |
492 | err = 0; | |
493 | break; | |
494 | ||
495 | case PPPIOCGXASYNCMAP: | |
496 | if (copy_to_user(argp, ap->xaccm, sizeof(ap->xaccm))) | |
497 | break; | |
498 | err = 0; | |
499 | break; | |
500 | case PPPIOCSXASYNCMAP: | |
501 | if (copy_from_user(accm, argp, sizeof(accm))) | |
502 | break; | |
503 | accm[2] &= ~0x40000000U; /* can't escape 0x5e */ | |
504 | accm[3] |= 0x60000000U; /* must escape 0x7d, 0x7e */ | |
505 | memcpy(ap->xaccm, accm, sizeof(ap->xaccm)); | |
506 | err = 0; | |
507 | break; | |
508 | ||
509 | case PPPIOCGMRU: | |
510 | if (put_user(ap->mru, (int __user *) argp)) | |
511 | break; | |
512 | err = 0; | |
513 | break; | |
514 | case PPPIOCSMRU: | |
515 | if (get_user(val, (int __user *) argp)) | |
516 | break; | |
517 | if (val < PPP_MRU) | |
518 | val = PPP_MRU; | |
519 | ap->mru = val; | |
520 | err = 0; | |
521 | break; | |
522 | ||
523 | default: | |
524 | err = -ENOTTY; | |
525 | } | |
526 | return err; | |
527 | } | |
528 | ||
529 | /* | |
530 | * This is called at softirq level to deliver received packets | |
531 | * to the ppp_generic code, and to tell the ppp_generic code | |
532 | * if we can accept more output now. | |
533 | */ | |
534 | static void ppp_sync_process(unsigned long arg) | |
535 | { | |
536 | struct syncppp *ap = (struct syncppp *) arg; | |
537 | struct sk_buff *skb; | |
538 | ||
539 | /* process received packets */ | |
540 | while ((skb = skb_dequeue(&ap->rqueue)) != NULL) { | |
541 | if (skb->len == 0) { | |
542 | /* zero length buffers indicate error */ | |
543 | ppp_input_error(&ap->chan, 0); | |
544 | kfree_skb(skb); | |
545 | } | |
546 | else | |
547 | ppp_input(&ap->chan, skb); | |
548 | } | |
549 | ||
550 | /* try to push more stuff out */ | |
551 | if (test_bit(XMIT_WAKEUP, &ap->xmit_flags) && ppp_sync_push(ap)) | |
552 | ppp_output_wakeup(&ap->chan); | |
553 | } | |
554 | ||
555 | /* | |
556 | * Procedures for encapsulation and framing. | |
557 | */ | |
558 | ||
3c582b30 | 559 | static struct sk_buff* |
1da177e4 LT |
560 | ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *skb) |
561 | { | |
562 | int proto; | |
563 | unsigned char *data; | |
564 | int islcp; | |
565 | ||
566 | data = skb->data; | |
96545aeb | 567 | proto = get_unaligned_be16(data); |
1da177e4 LT |
568 | |
569 | /* LCP packets with codes between 1 (configure-request) | |
570 | * and 7 (code-reject) must be sent as though no options | |
571 | * have been negotiated. | |
572 | */ | |
573 | islcp = proto == PPP_LCP && 1 <= data[2] && data[2] <= 7; | |
574 | ||
575 | /* compress protocol field if option enabled */ | |
576 | if (data[0] == 0 && (ap->flags & SC_COMP_PROT) && !islcp) | |
577 | skb_pull(skb,1); | |
578 | ||
579 | /* prepend address/control fields if necessary */ | |
580 | if ((ap->flags & SC_COMP_AC) == 0 || islcp) { | |
581 | if (skb_headroom(skb) < 2) { | |
582 | struct sk_buff *npkt = dev_alloc_skb(skb->len + 2); | |
583 | if (npkt == NULL) { | |
584 | kfree_skb(skb); | |
585 | return NULL; | |
586 | } | |
587 | skb_reserve(npkt,2); | |
d626f62b ACM |
588 | skb_copy_from_linear_data(skb, |
589 | skb_put(npkt, skb->len), skb->len); | |
1da177e4 LT |
590 | kfree_skb(skb); |
591 | skb = npkt; | |
592 | } | |
593 | skb_push(skb,2); | |
594 | skb->data[0] = PPP_ALLSTATIONS; | |
595 | skb->data[1] = PPP_UI; | |
596 | } | |
597 | ||
598 | ap->last_xmit = jiffies; | |
599 | ||
600 | if (skb && ap->flags & SC_LOG_OUTPKT) | |
601 | ppp_print_buffer ("send buffer", skb->data, skb->len); | |
602 | ||
603 | return skb; | |
604 | } | |
605 | ||
606 | /* | |
607 | * Transmit-side routines. | |
608 | */ | |
609 | ||
610 | /* | |
611 | * Send a packet to the peer over an sync tty line. | |
612 | * Returns 1 iff the packet was accepted. | |
613 | * If the packet was not accepted, we will call ppp_output_wakeup | |
614 | * at some later time. | |
615 | */ | |
616 | static int | |
617 | ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb) | |
618 | { | |
619 | struct syncppp *ap = chan->private; | |
620 | ||
621 | ppp_sync_push(ap); | |
622 | ||
623 | if (test_and_set_bit(XMIT_FULL, &ap->xmit_flags)) | |
624 | return 0; /* already full */ | |
625 | skb = ppp_sync_txmunge(ap, skb); | |
626 | if (skb != NULL) | |
627 | ap->tpkt = skb; | |
628 | else | |
629 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
630 | ||
631 | ppp_sync_push(ap); | |
632 | return 1; | |
633 | } | |
634 | ||
635 | /* | |
636 | * Push as much data as possible out to the tty. | |
637 | */ | |
638 | static int | |
639 | ppp_sync_push(struct syncppp *ap) | |
640 | { | |
641 | int sent, done = 0; | |
642 | struct tty_struct *tty = ap->tty; | |
643 | int tty_stuffed = 0; | |
644 | ||
645 | if (!spin_trylock_bh(&ap->xmit_lock)) | |
646 | return 0; | |
647 | for (;;) { | |
648 | if (test_and_clear_bit(XMIT_WAKEUP, &ap->xmit_flags)) | |
649 | tty_stuffed = 0; | |
cd228d54 | 650 | if (!tty_stuffed && ap->tpkt) { |
1da177e4 | 651 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
f34d7a5b | 652 | sent = tty->ops->write(tty, ap->tpkt->data, ap->tpkt->len); |
1da177e4 LT |
653 | if (sent < 0) |
654 | goto flush; /* error, e.g. loss of CD */ | |
655 | if (sent < ap->tpkt->len) { | |
656 | tty_stuffed = 1; | |
657 | } else { | |
658 | kfree_skb(ap->tpkt); | |
659 | ap->tpkt = NULL; | |
660 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
661 | done = 1; | |
662 | } | |
663 | continue; | |
664 | } | |
665 | /* haven't made any progress */ | |
666 | spin_unlock_bh(&ap->xmit_lock); | |
8e95a202 JP |
667 | if (!(test_bit(XMIT_WAKEUP, &ap->xmit_flags) || |
668 | (!tty_stuffed && ap->tpkt))) | |
1da177e4 LT |
669 | break; |
670 | if (!spin_trylock_bh(&ap->xmit_lock)) | |
671 | break; | |
672 | } | |
673 | return done; | |
674 | ||
675 | flush: | |
cd228d54 | 676 | if (ap->tpkt) { |
1da177e4 LT |
677 | kfree_skb(ap->tpkt); |
678 | ap->tpkt = NULL; | |
679 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
680 | done = 1; | |
681 | } | |
682 | spin_unlock_bh(&ap->xmit_lock); | |
683 | return done; | |
684 | } | |
685 | ||
686 | /* | |
687 | * Flush output from our internal buffers. | |
688 | * Called for the TCFLSH ioctl. | |
689 | */ | |
690 | static void | |
691 | ppp_sync_flush_output(struct syncppp *ap) | |
692 | { | |
693 | int done = 0; | |
694 | ||
695 | spin_lock_bh(&ap->xmit_lock); | |
696 | if (ap->tpkt != NULL) { | |
697 | kfree_skb(ap->tpkt); | |
698 | ap->tpkt = NULL; | |
699 | clear_bit(XMIT_FULL, &ap->xmit_flags); | |
700 | done = 1; | |
701 | } | |
702 | spin_unlock_bh(&ap->xmit_lock); | |
703 | if (done) | |
704 | ppp_output_wakeup(&ap->chan); | |
705 | } | |
706 | ||
707 | /* | |
708 | * Receive-side routines. | |
709 | */ | |
710 | ||
711 | /* called when the tty driver has data for us. | |
712 | * | |
713 | * Data is frame oriented: each call to ppp_sync_input is considered | |
714 | * a whole frame. If the 1st flag byte is non-zero then the whole | |
715 | * frame is considered to be in error and is tossed. | |
716 | */ | |
717 | static void | |
718 | ppp_sync_input(struct syncppp *ap, const unsigned char *buf, | |
719 | char *flags, int count) | |
720 | { | |
721 | struct sk_buff *skb; | |
722 | unsigned char *p; | |
723 | ||
724 | if (count == 0) | |
725 | return; | |
726 | ||
727 | if (ap->flags & SC_LOG_INPKT) | |
728 | ppp_print_buffer ("receive buffer", buf, count); | |
729 | ||
730 | /* stuff the chars in the skb */ | |
cd228d54 JP |
731 | skb = dev_alloc_skb(ap->mru + PPP_HDRLEN + 2); |
732 | if (!skb) { | |
1da177e4 LT |
733 | printk(KERN_ERR "PPPsync: no memory (input pkt)\n"); |
734 | goto err; | |
735 | } | |
736 | /* Try to get the payload 4-byte aligned */ | |
737 | if (buf[0] != PPP_ALLSTATIONS) | |
738 | skb_reserve(skb, 2 + (buf[0] & 1)); | |
739 | ||
cd228d54 | 740 | if (flags && *flags) { |
1da177e4 LT |
741 | /* error flag set, ignore frame */ |
742 | goto err; | |
743 | } else if (count > skb_tailroom(skb)) { | |
744 | /* packet overflowed MRU */ | |
745 | goto err; | |
746 | } | |
747 | ||
748 | p = skb_put(skb, count); | |
749 | memcpy(p, buf, count); | |
750 | ||
751 | /* strip address/control field if present */ | |
752 | p = skb->data; | |
753 | if (p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) { | |
754 | /* chop off address/control */ | |
755 | if (skb->len < 3) | |
756 | goto err; | |
757 | p = skb_pull(skb, 2); | |
758 | } | |
759 | ||
760 | /* decompress protocol field if compressed */ | |
761 | if (p[0] & 1) { | |
762 | /* protocol is compressed */ | |
763 | skb_push(skb, 1)[0] = 0; | |
764 | } else if (skb->len < 2) | |
765 | goto err; | |
766 | ||
767 | /* queue the frame to be processed */ | |
768 | skb_queue_tail(&ap->rqueue, skb); | |
769 | return; | |
770 | ||
771 | err: | |
772 | /* queue zero length packet as error indication */ | |
773 | if (skb || (skb = dev_alloc_skb(0))) { | |
774 | skb_trim(skb, 0); | |
775 | skb_queue_tail(&ap->rqueue, skb); | |
776 | } | |
777 | } | |
778 | ||
779 | static void __exit | |
780 | ppp_sync_cleanup(void) | |
781 | { | |
64ccd715 | 782 | if (tty_unregister_ldisc(N_SYNC_PPP) != 0) |
1da177e4 LT |
783 | printk(KERN_ERR "failed to unregister Sync PPP line discipline\n"); |
784 | } | |
785 | ||
786 | module_init(ppp_sync_init); | |
787 | module_exit(ppp_sync_cleanup); | |
788 | MODULE_LICENSE("GPL"); | |
789 | MODULE_ALIAS_LDISC(N_SYNC_PPP); |