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Diffstat (limited to 'drivers/net/ppp/ppp_mppe.c')
-rw-r--r--drivers/net/ppp/ppp_mppe.c740
1 files changed, 740 insertions, 0 deletions
diff --git a/drivers/net/ppp/ppp_mppe.c b/drivers/net/ppp/ppp_mppe.c
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index 000000000000..9a1849a83e2a
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1/*
2 * ppp_mppe.c - interface MPPE to the PPP code.
3 * This version is for use with Linux kernel 2.6.14+
4 *
5 * By Frank Cusack <fcusack@fcusack.com>.
6 * Copyright (c) 2002,2003,2004 Google, Inc.
7 * All rights reserved.
8 *
9 * License:
10 * Permission to use, copy, modify, and distribute this software and its
11 * documentation is hereby granted, provided that the above copyright
12 * notice appears in all copies. This software is provided without any
13 * warranty, express or implied.
14 *
15 * ALTERNATIVELY, provided that this notice is retained in full, this product
16 * may be distributed under the terms of the GNU General Public License (GPL),
17 * in which case the provisions of the GPL apply INSTEAD OF those given above.
18 *
19 * This program is free software; you can redistribute it and/or modify
20 * it under the terms of the GNU General Public License as published by
21 * the Free Software Foundation; either version 2 of the License, or
22 * (at your option) any later version.
23 *
24 * This program is distributed in the hope that it will be useful,
25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
27 * GNU General Public License for more details.
28 *
29 * You should have received a copy of the GNU General Public License
30 * along with this program; if not, write to the Free Software
31 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
32 *
33 *
34 * Changelog:
35 * 08/12/05 - Matt Domsch <Matt_Domsch@dell.com>
36 * Only need extra skb padding on transmit, not receive.
37 * 06/18/04 - Matt Domsch <Matt_Domsch@dell.com>, Oleg Makarenko <mole@quadra.ru>
38 * Use Linux kernel 2.6 arc4 and sha1 routines rather than
39 * providing our own.
40 * 2/15/04 - TS: added #include <version.h> and testing for Kernel
41 * version before using
42 * MOD_DEC_USAGE_COUNT/MOD_INC_USAGE_COUNT which are
43 * deprecated in 2.6
44 */
45
46#include <linux/err.h>
47#include <linux/module.h>
48#include <linux/kernel.h>
49#include <linux/init.h>
50#include <linux/types.h>
51#include <linux/slab.h>
52#include <linux/string.h>
53#include <linux/crypto.h>
54#include <linux/mm.h>
55#include <linux/ppp_defs.h>
56#include <linux/ppp-comp.h>
57#include <linux/scatterlist.h>
58#include <asm/unaligned.h>
59
60#include "ppp_mppe.h"
61
62MODULE_AUTHOR("Frank Cusack <fcusack@fcusack.com>");
63MODULE_DESCRIPTION("Point-to-Point Protocol Microsoft Point-to-Point Encryption support");
64MODULE_LICENSE("Dual BSD/GPL");
65MODULE_ALIAS("ppp-compress-" __stringify(CI_MPPE));
66MODULE_VERSION("1.0.2");
67
68static unsigned int
69setup_sg(struct scatterlist *sg, const void *address, unsigned int length)
70{
71 sg_set_buf(sg, address, length);
72 return length;
73}
74
75#define SHA1_PAD_SIZE 40
76
77/*
78 * kernel crypto API needs its arguments to be in kmalloc'd memory, not in the module
79 * static data area. That means sha_pad needs to be kmalloc'd.
80 */
81
82struct sha_pad {
83 unsigned char sha_pad1[SHA1_PAD_SIZE];
84 unsigned char sha_pad2[SHA1_PAD_SIZE];
85};
86static struct sha_pad *sha_pad;
87
88static inline void sha_pad_init(struct sha_pad *shapad)
89{
90 memset(shapad->sha_pad1, 0x00, sizeof(shapad->sha_pad1));
91 memset(shapad->sha_pad2, 0xF2, sizeof(shapad->sha_pad2));
92}
93
94/*
95 * State for an MPPE (de)compressor.
96 */
97struct ppp_mppe_state {
98 struct crypto_blkcipher *arc4;
99 struct crypto_hash *sha1;
100 unsigned char *sha1_digest;
101 unsigned char master_key[MPPE_MAX_KEY_LEN];
102 unsigned char session_key[MPPE_MAX_KEY_LEN];
103 unsigned keylen; /* key length in bytes */
104 /* NB: 128-bit == 16, 40-bit == 8! */
105 /* If we want to support 56-bit, */
106 /* the unit has to change to bits */
107 unsigned char bits; /* MPPE control bits */
108 unsigned ccount; /* 12-bit coherency count (seqno) */
109 unsigned stateful; /* stateful mode flag */
110 int discard; /* stateful mode packet loss flag */
111 int sanity_errors; /* take down LCP if too many */
112 int unit;
113 int debug;
114 struct compstat stats;
115};
116
117/* struct ppp_mppe_state.bits definitions */
118#define MPPE_BIT_A 0x80 /* Encryption table were (re)inititalized */
119#define MPPE_BIT_B 0x40 /* MPPC only (not implemented) */
120#define MPPE_BIT_C 0x20 /* MPPC only (not implemented) */
121#define MPPE_BIT_D 0x10 /* This is an encrypted frame */
122
123#define MPPE_BIT_FLUSHED MPPE_BIT_A
124#define MPPE_BIT_ENCRYPTED MPPE_BIT_D
125
126#define MPPE_BITS(p) ((p)[4] & 0xf0)
127#define MPPE_CCOUNT(p) ((((p)[4] & 0x0f) << 8) + (p)[5])
128#define MPPE_CCOUNT_SPACE 0x1000 /* The size of the ccount space */
129
130#define MPPE_OVHD 2 /* MPPE overhead/packet */
131#define SANITY_MAX 1600 /* Max bogon factor we will tolerate */
132
133/*
134 * Key Derivation, from RFC 3078, RFC 3079.
135 * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
136 */
137static void get_new_key_from_sha(struct ppp_mppe_state * state)
138{
139 struct hash_desc desc;
140 struct scatterlist sg[4];
141 unsigned int nbytes;
142
143 sg_init_table(sg, 4);
144
145 nbytes = setup_sg(&sg[0], state->master_key, state->keylen);
146 nbytes += setup_sg(&sg[1], sha_pad->sha_pad1,
147 sizeof(sha_pad->sha_pad1));
148 nbytes += setup_sg(&sg[2], state->session_key, state->keylen);
149 nbytes += setup_sg(&sg[3], sha_pad->sha_pad2,
150 sizeof(sha_pad->sha_pad2));
151
152 desc.tfm = state->sha1;
153 desc.flags = 0;
154
155 crypto_hash_digest(&desc, sg, nbytes, state->sha1_digest);
156}
157
158/*
159 * Perform the MPPE rekey algorithm, from RFC 3078, sec. 7.3.
160 * Well, not what's written there, but rather what they meant.
161 */
162static void mppe_rekey(struct ppp_mppe_state * state, int initial_key)
163{
164 struct scatterlist sg_in[1], sg_out[1];
165 struct blkcipher_desc desc = { .tfm = state->arc4 };
166
167 get_new_key_from_sha(state);
168 if (!initial_key) {
169 crypto_blkcipher_setkey(state->arc4, state->sha1_digest,
170 state->keylen);
171 sg_init_table(sg_in, 1);
172 sg_init_table(sg_out, 1);
173 setup_sg(sg_in, state->sha1_digest, state->keylen);
174 setup_sg(sg_out, state->session_key, state->keylen);
175 if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
176 state->keylen) != 0) {
177 printk(KERN_WARNING "mppe_rekey: cipher_encrypt failed\n");
178 }
179 } else {
180 memcpy(state->session_key, state->sha1_digest, state->keylen);
181 }
182 if (state->keylen == 8) {
183 /* See RFC 3078 */
184 state->session_key[0] = 0xd1;
185 state->session_key[1] = 0x26;
186 state->session_key[2] = 0x9e;
187 }
188 crypto_blkcipher_setkey(state->arc4, state->session_key, state->keylen);
189}
190
191/*
192 * Allocate space for a (de)compressor.
193 */
194static void *mppe_alloc(unsigned char *options, int optlen)
195{
196 struct ppp_mppe_state *state;
197 unsigned int digestsize;
198
199 if (optlen != CILEN_MPPE + sizeof(state->master_key) ||
200 options[0] != CI_MPPE || options[1] != CILEN_MPPE)
201 goto out;
202
203 state = kzalloc(sizeof(*state), GFP_KERNEL);
204 if (state == NULL)
205 goto out;
206
207
208 state->arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
209 if (IS_ERR(state->arc4)) {
210 state->arc4 = NULL;
211 goto out_free;
212 }
213
214 state->sha1 = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC);
215 if (IS_ERR(state->sha1)) {
216 state->sha1 = NULL;
217 goto out_free;
218 }
219
220 digestsize = crypto_hash_digestsize(state->sha1);
221 if (digestsize < MPPE_MAX_KEY_LEN)
222 goto out_free;
223
224 state->sha1_digest = kmalloc(digestsize, GFP_KERNEL);
225 if (!state->sha1_digest)
226 goto out_free;
227
228 /* Save keys. */
229 memcpy(state->master_key, &options[CILEN_MPPE],
230 sizeof(state->master_key));
231 memcpy(state->session_key, state->master_key,
232 sizeof(state->master_key));
233
234 /*
235 * We defer initial key generation until mppe_init(), as mppe_alloc()
236 * is called frequently during negotiation.
237 */
238
239 return (void *)state;
240
241 out_free:
242 if (state->sha1_digest)
243 kfree(state->sha1_digest);
244 if (state->sha1)
245 crypto_free_hash(state->sha1);
246 if (state->arc4)
247 crypto_free_blkcipher(state->arc4);
248 kfree(state);
249 out:
250 return NULL;
251}
252
253/*
254 * Deallocate space for a (de)compressor.
255 */
256static void mppe_free(void *arg)
257{
258 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
259 if (state) {
260 if (state->sha1_digest)
261 kfree(state->sha1_digest);
262 if (state->sha1)
263 crypto_free_hash(state->sha1);
264 if (state->arc4)
265 crypto_free_blkcipher(state->arc4);
266 kfree(state);
267 }
268}
269
270/*
271 * Initialize (de)compressor state.
272 */
273static int
274mppe_init(void *arg, unsigned char *options, int optlen, int unit, int debug,
275 const char *debugstr)
276{
277 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
278 unsigned char mppe_opts;
279
280 if (optlen != CILEN_MPPE ||
281 options[0] != CI_MPPE || options[1] != CILEN_MPPE)
282 return 0;
283
284 MPPE_CI_TO_OPTS(&options[2], mppe_opts);
285 if (mppe_opts & MPPE_OPT_128)
286 state->keylen = 16;
287 else if (mppe_opts & MPPE_OPT_40)
288 state->keylen = 8;
289 else {
290 printk(KERN_WARNING "%s[%d]: unknown key length\n", debugstr,
291 unit);
292 return 0;
293 }
294 if (mppe_opts & MPPE_OPT_STATEFUL)
295 state->stateful = 1;
296
297 /* Generate the initial session key. */
298 mppe_rekey(state, 1);
299
300 if (debug) {
301 int i;
302 char mkey[sizeof(state->master_key) * 2 + 1];
303 char skey[sizeof(state->session_key) * 2 + 1];
304
305 printk(KERN_DEBUG "%s[%d]: initialized with %d-bit %s mode\n",
306 debugstr, unit, (state->keylen == 16) ? 128 : 40,
307 (state->stateful) ? "stateful" : "stateless");
308
309 for (i = 0; i < sizeof(state->master_key); i++)
310 sprintf(mkey + i * 2, "%02x", state->master_key[i]);
311 for (i = 0; i < sizeof(state->session_key); i++)
312 sprintf(skey + i * 2, "%02x", state->session_key[i]);
313 printk(KERN_DEBUG
314 "%s[%d]: keys: master: %s initial session: %s\n",
315 debugstr, unit, mkey, skey);
316 }
317
318 /*
319 * Initialize the coherency count. The initial value is not specified
320 * in RFC 3078, but we can make a reasonable assumption that it will
321 * start at 0. Setting it to the max here makes the comp/decomp code
322 * do the right thing (determined through experiment).
323 */
324 state->ccount = MPPE_CCOUNT_SPACE - 1;
325
326 /*
327 * Note that even though we have initialized the key table, we don't
328 * set the FLUSHED bit. This is contrary to RFC 3078, sec. 3.1.
329 */
330 state->bits = MPPE_BIT_ENCRYPTED;
331
332 state->unit = unit;
333 state->debug = debug;
334
335 return 1;
336}
337
338static int
339mppe_comp_init(void *arg, unsigned char *options, int optlen, int unit,
340 int hdrlen, int debug)
341{
342 /* ARGSUSED */
343 return mppe_init(arg, options, optlen, unit, debug, "mppe_comp_init");
344}
345
346/*
347 * We received a CCP Reset-Request (actually, we are sending a Reset-Ack),
348 * tell the compressor to rekey. Note that we MUST NOT rekey for
349 * every CCP Reset-Request; we only rekey on the next xmit packet.
350 * We might get multiple CCP Reset-Requests if our CCP Reset-Ack is lost.
351 * So, rekeying for every CCP Reset-Request is broken as the peer will not
352 * know how many times we've rekeyed. (If we rekey and THEN get another
353 * CCP Reset-Request, we must rekey again.)
354 */
355static void mppe_comp_reset(void *arg)
356{
357 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
358
359 state->bits |= MPPE_BIT_FLUSHED;
360}
361
362/*
363 * Compress (encrypt) a packet.
364 * It's strange to call this a compressor, since the output is always
365 * MPPE_OVHD + 2 bytes larger than the input.
366 */
367static int
368mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf,
369 int isize, int osize)
370{
371 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
372 struct blkcipher_desc desc = { .tfm = state->arc4 };
373 int proto;
374 struct scatterlist sg_in[1], sg_out[1];
375
376 /*
377 * Check that the protocol is in the range we handle.
378 */
379 proto = PPP_PROTOCOL(ibuf);
380 if (proto < 0x0021 || proto > 0x00fa)
381 return 0;
382
383 /* Make sure we have enough room to generate an encrypted packet. */
384 if (osize < isize + MPPE_OVHD + 2) {
385 /* Drop the packet if we should encrypt it, but can't. */
386 printk(KERN_DEBUG "mppe_compress[%d]: osize too small! "
387 "(have: %d need: %d)\n", state->unit,
388 osize, osize + MPPE_OVHD + 2);
389 return -1;
390 }
391
392 osize = isize + MPPE_OVHD + 2;
393
394 /*
395 * Copy over the PPP header and set control bits.
396 */
397 obuf[0] = PPP_ADDRESS(ibuf);
398 obuf[1] = PPP_CONTROL(ibuf);
399 put_unaligned_be16(PPP_COMP, obuf + 2);
400 obuf += PPP_HDRLEN;
401
402 state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
403 if (state->debug >= 7)
404 printk(KERN_DEBUG "mppe_compress[%d]: ccount %d\n", state->unit,
405 state->ccount);
406 put_unaligned_be16(state->ccount, obuf);
407
408 if (!state->stateful || /* stateless mode */
409 ((state->ccount & 0xff) == 0xff) || /* "flag" packet */
410 (state->bits & MPPE_BIT_FLUSHED)) { /* CCP Reset-Request */
411 /* We must rekey */
412 if (state->debug && state->stateful)
413 printk(KERN_DEBUG "mppe_compress[%d]: rekeying\n",
414 state->unit);
415 mppe_rekey(state, 0);
416 state->bits |= MPPE_BIT_FLUSHED;
417 }
418 obuf[0] |= state->bits;
419 state->bits &= ~MPPE_BIT_FLUSHED; /* reset for next xmit */
420
421 obuf += MPPE_OVHD;
422 ibuf += 2; /* skip to proto field */
423 isize -= 2;
424
425 /* Encrypt packet */
426 sg_init_table(sg_in, 1);
427 sg_init_table(sg_out, 1);
428 setup_sg(sg_in, ibuf, isize);
429 setup_sg(sg_out, obuf, osize);
430 if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in, isize) != 0) {
431 printk(KERN_DEBUG "crypto_cypher_encrypt failed\n");
432 return -1;
433 }
434
435 state->stats.unc_bytes += isize;
436 state->stats.unc_packets++;
437 state->stats.comp_bytes += osize;
438 state->stats.comp_packets++;
439
440 return osize;
441}
442
443/*
444 * Since every frame grows by MPPE_OVHD + 2 bytes, this is always going
445 * to look bad ... and the longer the link is up the worse it will get.
446 */
447static void mppe_comp_stats(void *arg, struct compstat *stats)
448{
449 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
450
451 *stats = state->stats;
452}
453
454static int
455mppe_decomp_init(void *arg, unsigned char *options, int optlen, int unit,
456 int hdrlen, int mru, int debug)
457{
458 /* ARGSUSED */
459 return mppe_init(arg, options, optlen, unit, debug, "mppe_decomp_init");
460}
461
462/*
463 * We received a CCP Reset-Ack. Just ignore it.
464 */
465static void mppe_decomp_reset(void *arg)
466{
467 /* ARGSUSED */
468 return;
469}
470
471/*
472 * Decompress (decrypt) an MPPE packet.
473 */
474static int
475mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf,
476 int osize)
477{
478 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
479 struct blkcipher_desc desc = { .tfm = state->arc4 };
480 unsigned ccount;
481 int flushed = MPPE_BITS(ibuf) & MPPE_BIT_FLUSHED;
482 int sanity = 0;
483 struct scatterlist sg_in[1], sg_out[1];
484
485 if (isize <= PPP_HDRLEN + MPPE_OVHD) {
486 if (state->debug)
487 printk(KERN_DEBUG
488 "mppe_decompress[%d]: short pkt (%d)\n",
489 state->unit, isize);
490 return DECOMP_ERROR;
491 }
492
493 /*
494 * Make sure we have enough room to decrypt the packet.
495 * Note that for our test we only subtract 1 byte whereas in
496 * mppe_compress() we added 2 bytes (+MPPE_OVHD);
497 * this is to account for possible PFC.
498 */
499 if (osize < isize - MPPE_OVHD - 1) {
500 printk(KERN_DEBUG "mppe_decompress[%d]: osize too small! "
501 "(have: %d need: %d)\n", state->unit,
502 osize, isize - MPPE_OVHD - 1);
503 return DECOMP_ERROR;
504 }
505 osize = isize - MPPE_OVHD - 2; /* assume no PFC */
506
507 ccount = MPPE_CCOUNT(ibuf);
508 if (state->debug >= 7)
509 printk(KERN_DEBUG "mppe_decompress[%d]: ccount %d\n",
510 state->unit, ccount);
511
512 /* sanity checks -- terminate with extreme prejudice */
513 if (!(MPPE_BITS(ibuf) & MPPE_BIT_ENCRYPTED)) {
514 printk(KERN_DEBUG
515 "mppe_decompress[%d]: ENCRYPTED bit not set!\n",
516 state->unit);
517 state->sanity_errors += 100;
518 sanity = 1;
519 }
520 if (!state->stateful && !flushed) {
521 printk(KERN_DEBUG "mppe_decompress[%d]: FLUSHED bit not set in "
522 "stateless mode!\n", state->unit);
523 state->sanity_errors += 100;
524 sanity = 1;
525 }
526 if (state->stateful && ((ccount & 0xff) == 0xff) && !flushed) {
527 printk(KERN_DEBUG "mppe_decompress[%d]: FLUSHED bit not set on "
528 "flag packet!\n", state->unit);
529 state->sanity_errors += 100;
530 sanity = 1;
531 }
532
533 if (sanity) {
534 if (state->sanity_errors < SANITY_MAX)
535 return DECOMP_ERROR;
536 else
537 /*
538 * Take LCP down if the peer is sending too many bogons.
539 * We don't want to do this for a single or just a few
540 * instances since it could just be due to packet corruption.
541 */
542 return DECOMP_FATALERROR;
543 }
544
545 /*
546 * Check the coherency count.
547 */
548
549 if (!state->stateful) {
550 /* RFC 3078, sec 8.1. Rekey for every packet. */
551 while (state->ccount != ccount) {
552 mppe_rekey(state, 0);
553 state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
554 }
555 } else {
556 /* RFC 3078, sec 8.2. */
557 if (!state->discard) {
558 /* normal state */
559 state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
560 if (ccount != state->ccount) {
561 /*
562 * (ccount > state->ccount)
563 * Packet loss detected, enter the discard state.
564 * Signal the peer to rekey (by sending a CCP Reset-Request).
565 */
566 state->discard = 1;
567 return DECOMP_ERROR;
568 }
569 } else {
570 /* discard state */
571 if (!flushed) {
572 /* ccp.c will be silent (no additional CCP Reset-Requests). */
573 return DECOMP_ERROR;
574 } else {
575 /* Rekey for every missed "flag" packet. */
576 while ((ccount & ~0xff) !=
577 (state->ccount & ~0xff)) {
578 mppe_rekey(state, 0);
579 state->ccount =
580 (state->ccount +
581 256) % MPPE_CCOUNT_SPACE;
582 }
583
584 /* reset */
585 state->discard = 0;
586 state->ccount = ccount;
587 /*
588 * Another problem with RFC 3078 here. It implies that the
589 * peer need not send a Reset-Ack packet. But RFC 1962
590 * requires it. Hopefully, M$ does send a Reset-Ack; even
591 * though it isn't required for MPPE synchronization, it is
592 * required to reset CCP state.
593 */
594 }
595 }
596 if (flushed)
597 mppe_rekey(state, 0);
598 }
599
600 /*
601 * Fill in the first part of the PPP header. The protocol field
602 * comes from the decrypted data.
603 */
604 obuf[0] = PPP_ADDRESS(ibuf); /* +1 */
605 obuf[1] = PPP_CONTROL(ibuf); /* +1 */
606 obuf += 2;
607 ibuf += PPP_HDRLEN + MPPE_OVHD;
608 isize -= PPP_HDRLEN + MPPE_OVHD; /* -6 */
609 /* net osize: isize-4 */
610
611 /*
612 * Decrypt the first byte in order to check if it is
613 * a compressed or uncompressed protocol field.
614 */
615 sg_init_table(sg_in, 1);
616 sg_init_table(sg_out, 1);
617 setup_sg(sg_in, ibuf, 1);
618 setup_sg(sg_out, obuf, 1);
619 if (crypto_blkcipher_decrypt(&desc, sg_out, sg_in, 1) != 0) {
620 printk(KERN_DEBUG "crypto_cypher_decrypt failed\n");
621 return DECOMP_ERROR;
622 }
623
624 /*
625 * Do PFC decompression.
626 * This would be nicer if we were given the actual sk_buff
627 * instead of a char *.
628 */
629 if ((obuf[0] & 0x01) != 0) {
630 obuf[1] = obuf[0];
631 obuf[0] = 0;
632 obuf++;
633 osize++;
634 }
635
636 /* And finally, decrypt the rest of the packet. */
637 setup_sg(sg_in, ibuf + 1, isize - 1);
638 setup_sg(sg_out, obuf + 1, osize - 1);
639 if (crypto_blkcipher_decrypt(&desc, sg_out, sg_in, isize - 1)) {
640 printk(KERN_DEBUG "crypto_cypher_decrypt failed\n");
641 return DECOMP_ERROR;
642 }
643
644 state->stats.unc_bytes += osize;
645 state->stats.unc_packets++;
646 state->stats.comp_bytes += isize;
647 state->stats.comp_packets++;
648
649 /* good packet credit */
650 state->sanity_errors >>= 1;
651
652 return osize;
653}
654
655/*
656 * Incompressible data has arrived (this should never happen!).
657 * We should probably drop the link if the protocol is in the range
658 * of what should be encrypted. At the least, we should drop this
659 * packet. (How to do this?)
660 */
661static void mppe_incomp(void *arg, unsigned char *ibuf, int icnt)
662{
663 struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
664
665 if (state->debug &&
666 (PPP_PROTOCOL(ibuf) >= 0x0021 && PPP_PROTOCOL(ibuf) <= 0x00fa))
667 printk(KERN_DEBUG
668 "mppe_incomp[%d]: incompressible (unencrypted) data! "
669 "(proto %04x)\n", state->unit, PPP_PROTOCOL(ibuf));
670
671 state->stats.inc_bytes += icnt;
672 state->stats.inc_packets++;
673 state->stats.unc_bytes += icnt;
674 state->stats.unc_packets++;
675}
676
677/*************************************************************
678 * Module interface table
679 *************************************************************/
680
681/*
682 * Procedures exported to if_ppp.c.
683 */
684static struct compressor ppp_mppe = {
685 .compress_proto = CI_MPPE,
686 .comp_alloc = mppe_alloc,
687 .comp_free = mppe_free,
688 .comp_init = mppe_comp_init,
689 .comp_reset = mppe_comp_reset,
690 .compress = mppe_compress,
691 .comp_stat = mppe_comp_stats,
692 .decomp_alloc = mppe_alloc,
693 .decomp_free = mppe_free,
694 .decomp_init = mppe_decomp_init,
695 .decomp_reset = mppe_decomp_reset,
696 .decompress = mppe_decompress,
697 .incomp = mppe_incomp,
698 .decomp_stat = mppe_comp_stats,
699 .owner = THIS_MODULE,
700 .comp_extra = MPPE_PAD,
701};
702
703/*
704 * ppp_mppe_init()
705 *
706 * Prior to allowing load, try to load the arc4 and sha1 crypto
707 * libraries. The actual use will be allocated later, but
708 * this way the module will fail to insmod if they aren't available.
709 */
710
711static int __init ppp_mppe_init(void)
712{
713 int answer;
714 if (!(crypto_has_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC) &&
715 crypto_has_hash("sha1", 0, CRYPTO_ALG_ASYNC)))
716 return -ENODEV;
717
718 sha_pad = kmalloc(sizeof(struct sha_pad), GFP_KERNEL);
719 if (!sha_pad)
720 return -ENOMEM;
721 sha_pad_init(sha_pad);
722
723 answer = ppp_register_compressor(&ppp_mppe);
724
725 if (answer == 0)
726 printk(KERN_INFO "PPP MPPE Compression module registered\n");
727 else
728 kfree(sha_pad);
729
730 return answer;
731}
732
733static void __exit ppp_mppe_cleanup(void)
734{
735 ppp_unregister_compressor(&ppp_mppe);
736 kfree(sha_pad);
737}
738
739module_init(ppp_mppe_init);
740module_exit(ppp_mppe_cleanup);
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