Root/target/linux/generic-2.4/patches/106-mppe_mppc.patch

1MPPE/MPPC kernel module for Linux
2
3Microsoft Point-to-Point Encryption / Compression support
4
5  http://www.polbox.com/h/hs001/linux-2.4.29-mppe-mppc-1.3.patch.gz
6
7--- a/Documentation/Configure.help
8+++ b/Documentation/Configure.help
9@@ -9986,6 +9986,28 @@ CONFIG_PPP_BSDCOMP
10   module; it is called bsd_comp.o and will show up in the directory
11   modules once you have said "make modules". If unsure, say N.
12 
13+Microsoft PPP compression/encryption (MPPC/MPPE)
14+CONFIG_PPP_MPPE_MPPC
15+ Support for the Microsoft Point-To-Point Compression (RFC2118) and
16+ Microsoft Point-To-Point Encryption (RFC3078). These protocols are
17+ supported by Microsoft Windows and wide range of "hardware" access
18+ servers. MPPE is common protocol in Virtual Private Networks. According
19+ to RFC3078, MPPE supports 40, 56 and 128-bit key lengths. Depending on
20+ PPP daemon configuration on both ends of the link, following scenarios
21+ are possible:
22+ - only compression (MPPC) is used,
23+ - only encryption (MPPE) is used,
24+ - compression and encryption (MPPC+MPPE) are used.
25+
26+ Please note that Hi/Fn (http://www.hifn.com) holds patent on MPPC so
27+ you should check if this patent is valid in your country in order to
28+ avoid legal problems.
29+
30+ For more information please visit http://free.polbox.pl/h/hs001
31+
32+ To compile this driver as a module, choose M here. The module will
33+ be called ppp_mppe_mppc.o.
34+
35 PPP over Ethernet
36 CONFIG_PPPOE
37   Support for PPP over Ethernet.
38--- a/crypto/Config.in
39+++ b/crypto/Config.in
40@@ -11,7 +11,9 @@ if [ "$CONFIG_INET_AH" = "y" -o \
41      "$CONFIG_INET6_AH" = "y" -o \
42      "$CONFIG_INET6_AH" = "m" -o \
43      "$CONFIG_INET6_ESP" = "y" -o \
44- "$CONFIG_INET6_ESP" = "m" ]; then
45+ "$CONFIG_INET6_ESP" = "m" -o \
46+ "$CONFIG_PPP_MPPE_MPPC" = "y" -o \
47+ "$CONFIG_PPP_MPPE_MPPC" = "m" ]; then
48   define_bool CONFIG_CRYPTO y
49 else
50   bool 'Cryptographic API' CONFIG_CRYPTO
51@@ -51,11 +53,24 @@ if [ "$CONFIG_CRYPTO" = "y" ]; then
52        "$CONFIG_INET6_AH" = "y" -o \
53        "$CONFIG_INET6_AH" = "m" -o \
54        "$CONFIG_INET6_ESP" = "y" -o \
55- "$CONFIG_INET6_ESP" = "m" ]; then
56- define_bool CONFIG_CRYPTO_SHA1 y
57- else
58- tristate ' SHA1 digest algorithm' CONFIG_CRYPTO_SHA1
59+ "$CONFIG_INET6_ESP" = "m" -o \
60+ "$CONFIG_PPP_MPPE_MPPC" = "y" -o \
61+ "$CONFIG_PPP_MPPE_MPPC" = "m" ]; then
62+ if [ "$CONFIG_INET_AH" = "y" -o \
63+ "$CONFIG_INET_ESP" = "y" -o \
64+ "$CONFIG_INET6_AH" = "y" -o \
65+ "$CONFIG_INET6_ESP" = "y" -o \
66+ "$CONFIG_PPP_MPPE_MPPC" = "y" ]; then
67+ define_tristate CONFIG_CRYPTO_SHA1 y
68+ else
69+ if [ "$CONFIG_CRYPTO_SHA1" != "y" -a \
70+ "$CONFIG_CRYPTO_SHA1" != "m" ]; then
71+ define_tristate CONFIG_CRYPTO_SHA1 m
72+ fi
73+ fi
74   fi
75+ tristate ' SHA1 digest algorithm' CONFIG_CRYPTO_SHA1
76+
77   tristate ' SHA256 digest algorithm' CONFIG_CRYPTO_SHA256
78   tristate ' SHA384 and SHA512 digest algorithms' CONFIG_CRYPTO_SHA512
79   tristate ' Whirlpool digest algorithms' CONFIG_CRYPTO_WP512
80@@ -76,7 +91,20 @@ if [ "$CONFIG_CRYPTO" = "y" ]; then
81   tristate ' TEA and XTEA cipher algorithms' CONFIG_CRYPTO_TEA
82   tristate ' Khazad cipher algorithm' CONFIG_CRYPTO_KHAZAD
83   tristate ' Anubis cipher algorithm' CONFIG_CRYPTO_ANUBIS
84+
85+ if [ "$CONFIG_PPP_MPPE_MPPC" = "y" -o \
86+ "$CONFIG_PPP_MPPE_MPPC" = "m" ]; then
87+ if [ "$CONFIG_PPP_MPPE_MPPC" = "y" ]; then
88+ define_tristate CONFIG_CRYPTO_ARC4 y
89+ else
90+ if [ "$CONFIG_CRYPTO_ARC4" != "y" -a \
91+ "$CONFIG_CRYPTO_ARC4" != "m" ]; then
92+ define_tristate CONFIG_CRYPTO_ARC4 m
93+ fi
94+ fi
95+ fi
96   tristate ' ARC4 cipher algorithm' CONFIG_CRYPTO_ARC4
97+
98   if [ "$CONFIG_INET_IPCOMP" = "y" -o \
99        "$CONFIG_INET_IPCOMP" = "m" -o \
100        "$CONFIG_INET6_IPCOMP" = "y" -o \
101--- a/drivers/net/Config.in
102+++ b/drivers/net/Config.in
103@@ -336,6 +336,7 @@ if [ ! "$CONFIG_PPP" = "n" ]; then
104    dep_tristate ' PPP support for sync tty ports' CONFIG_PPP_SYNC_TTY $CONFIG_PPP
105    dep_tristate ' PPP Deflate compression' CONFIG_PPP_DEFLATE $CONFIG_PPP
106    dep_tristate ' PPP BSD-Compress compression' CONFIG_PPP_BSDCOMP $CONFIG_PPP
107+ dep_tristate ' Microsoft PPP compression/encryption (MPPC/MPPE)' CONFIG_PPP_MPPE_MPPC $CONFIG_PPP
108    if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
109       dep_tristate ' PPP over Ethernet (EXPERIMENTAL)' CONFIG_PPPOE $CONFIG_PPP
110    fi
111--- a/drivers/net/Makefile
112+++ b/drivers/net/Makefile
113@@ -166,6 +166,7 @@ obj-$(CONFIG_PPP_ASYNC) += ppp_async.o
114 obj-$(CONFIG_PPP_SYNC_TTY) += ppp_synctty.o
115 obj-$(CONFIG_PPP_DEFLATE) += ppp_deflate.o
116 obj-$(CONFIG_PPP_BSDCOMP) += bsd_comp.o
117+obj-$(CONFIG_PPP_MPPE_MPPC) += ppp_mppe_mppc.o
118 obj-$(CONFIG_PPPOE) += pppox.o pppoe.o
119 
120 obj-$(CONFIG_SLIP) += slip.o
121--- a/drivers/net/ppp_generic.c
122+++ b/drivers/net/ppp_generic.c
123@@ -19,7 +19,7 @@
124  * PPP driver, written by Michael Callahan and Al Longyear, and
125  * subsequently hacked by Paul Mackerras.
126  *
127- * ==FILEVERSION 20020217==
128+ * ==FILEVERSION 20040509==
129  */
130 
131 #include <linux/config.h>
132@@ -102,6 +102,7 @@ struct ppp {
133     spinlock_t rlock; /* lock for receive side 58 */
134     spinlock_t wlock; /* lock for transmit side 5c */
135     int mru; /* max receive unit 60 */
136+ int mru_alloc; /* MAX(1500,MRU) for dev_alloc_skb() */
137     unsigned int flags; /* control bits 64 */
138     unsigned int xstate; /* transmit state bits 68 */
139     unsigned int rstate; /* receive state bits 6c */
140@@ -552,7 +553,9 @@ static int ppp_ioctl(struct inode *inode
141     case PPPIOCSMRU:
142         if (get_user(val, (int *) arg))
143             break;
144- ppp->mru = val;
145+ ppp->mru_alloc = ppp->mru = val;
146+ if (ppp->mru_alloc < PPP_MRU)
147+ ppp->mru_alloc = PPP_MRU; /* increase for broken peers */
148         err = 0;
149         break;
150 
151@@ -1025,14 +1028,37 @@ ppp_send_frame(struct ppp *ppp, struct s
152     case PPP_CCP:
153         /* peek at outbound CCP frames */
154         ppp_ccp_peek(ppp, skb, 0);
155+ /*
156+ * When LZS or MPPE/MPPC has been negotiated we don't send
157+ * CCP_RESETACK after receiving CCP_RESETREQ; in fact pppd
158+ * sends such a packet but we silently discard it here
159+ */
160+ if (CCP_CODE(skb->data+2) == CCP_RESETACK
161+ && (ppp->xcomp->compress_proto == CI_MPPE
162+ || ppp->xcomp->compress_proto == CI_LZS)) {
163+ --ppp->stats.tx_packets;
164+ ppp->stats.tx_bytes -= skb->len - 2;
165+ kfree_skb(skb);
166+ return;
167+ }
168         break;
169     }
170 
171     /* try to do packet compression */
172     if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0
173         && proto != PPP_LCP && proto != PPP_CCP) {
174- new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len,
175- GFP_ATOMIC);
176+ int comp_ovhd = 0;
177+ /*
178+ * because of possible data expansion when MPPC or LZS
179+ * is used, allocate compressor's buffer 12.5% bigger
180+ * than MTU
181+ */
182+ if (ppp->xcomp->compress_proto == CI_MPPE)
183+ comp_ovhd = ((ppp->dev->mtu * 9) / 8) + 1 + MPPE_OVHD;
184+ else if (ppp->xcomp->compress_proto == CI_LZS)
185+ comp_ovhd = ((ppp->dev->mtu * 9) / 8) + 1 + LZS_OVHD;
186+ new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len
187+ + comp_ovhd, GFP_ATOMIC);
188         if (new_skb == 0) {
189             printk(KERN_ERR "PPP: no memory (comp pkt)\n");
190             goto drop;
191@@ -1050,9 +1076,21 @@ ppp_send_frame(struct ppp *ppp, struct s
192             skb = new_skb;
193             skb_put(skb, len);
194             skb_pull(skb, 2); /* pull off A/C bytes */
195- } else {
196+ } else if (len == 0) {
197             /* didn't compress, or CCP not up yet */
198             kfree_skb(new_skb);
199+ } else {
200+ /*
201+ * (len < 0)
202+ * MPPE requires that we do not send unencrypted
203+ * frames. The compressor will return -1 if we
204+ * should drop the frame. We cannot simply test
205+ * the compress_proto because MPPE and MPPC share
206+ * the same number.
207+ */
208+ printk(KERN_ERR "ppp: compressor dropped pkt\n");
209+ kfree_skb(new_skb);
210+ goto drop;
211         }
212     }
213 
214@@ -1540,14 +1578,15 @@ ppp_decompress_frame(struct ppp *ppp, st
215     int len;
216 
217     if (proto == PPP_COMP) {
218- ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN);
219+ ns = dev_alloc_skb(ppp->mru_alloc + PPP_HDRLEN);
220         if (ns == 0) {
221             printk(KERN_ERR "ppp_decompress_frame: no memory\n");
222             goto err;
223         }
224         /* the decompressor still expects the A/C bytes in the hdr */
225         len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
226- skb->len + 2, ns->data, ppp->mru + PPP_HDRLEN);
227+ skb->len + 2, ns->data,
228+ ppp->mru_alloc + PPP_HDRLEN);
229         if (len < 0) {
230             /* Pass the compressed frame to pppd as an
231                error indication. */
232@@ -1573,7 +1612,14 @@ ppp_decompress_frame(struct ppp *ppp, st
233     return skb;
234 
235  err:
236- ppp->rstate |= SC_DC_ERROR;
237+ if (ppp->rcomp->compress_proto != CI_MPPE
238+ && ppp->rcomp->compress_proto != CI_LZS) {
239+ /*
240+ * If decompression protocol isn't MPPE/MPPC or LZS, we set
241+ * SC_DC_ERROR flag and wait for CCP_RESETACK
242+ */
243+ ppp->rstate |= SC_DC_ERROR;
244+ }
245     ppp_receive_error(ppp);
246     return skb;
247 }
248@@ -2253,6 +2299,7 @@ ppp_create_interface(int unit, int *retp
249     /* Initialize the new ppp unit */
250     ppp->file.index = unit;
251     ppp->mru = PPP_MRU;
252+ ppp->mru_alloc = PPP_MRU;
253     init_ppp_file(&ppp->file, INTERFACE);
254     ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
255     for (i = 0; i < NUM_NP; ++i)
256--- /dev/null
257+++ b/drivers/net/ppp_mppe_mppc.c
258@@ -0,0 +1,1312 @@
259+/*
260+ * ppp_mppe_mppc.c - MPPC/MPPE "compressor/decompressor" module.
261+ *
262+ * Copyright (c) 1994 Árpád Magosányi <mag@bunuel.tii.matav.hu>
263+ * Copyright (c) 1999 Tim Hockin, Cobalt Networks Inc. <thockin@cobaltnet.com>
264+ * Copyright (c) 2002-2005 Jan Dubiec <jdx@slackware.pl>
265+ *
266+ * Permission to use, copy, modify, and distribute this software and its
267+ * documentation is hereby granted, provided that the above copyright
268+ * notice appears in all copies. This software is provided without any
269+ * warranty, express or implied.
270+ *
271+ * The code is based on MPPE kernel module written by Árpád Magosányi and
272+ * Tim Hockin which can be found on http://planetmirror.com/pub/mppe/.
273+ * I have added MPPC and 56 bit session keys support in MPPE.
274+ *
275+ * WARNING! Although this is open source code, its usage in some countries
276+ * (in particular in the USA) may violate Stac Inc. patent for MPPC.
277+ *
278+ * ==FILEVERSION 20050202==
279+ *
280+ */
281+
282+#include <linux/init.h>
283+#include <linux/module.h>
284+#include <linux/mm.h>
285+#include <linux/slab.h>
286+#include <asm/scatterlist.h>
287+#include <linux/vmalloc.h>
288+#include <linux/crypto.h>
289+
290+#include <linux/ppp_defs.h>
291+#include <linux/ppp-comp.h>
292+
293+/*
294+ * In 2.4.x kernels macro offset_in_page() is not defined in linux/mm.h so
295+ * we define it here; PAGE_MASK is defined in asm/page.h which is included
296+ * by linux/mm.h.
297+ */
298+#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
299+
300+/*
301+ * State for a mppc/mppe "(de)compressor".
302+ */
303+struct ppp_mppe_state {
304+ struct crypto_tfm *arc4_tfm;
305+ struct crypto_tfm *sha1_tfm;
306+ u8 *sha1_digest;
307+ u8 master_key[MPPE_MAX_KEY_LEN];
308+ u8 session_key[MPPE_MAX_KEY_LEN];
309+ u8 mppc; /* do we use compression (MPPC)? */
310+ u8 mppe; /* do we use encryption (MPPE)? */
311+ u8 keylen; /* key length in bytes */
312+ u8 bitkeylen; /* key length in bits */
313+ u16 ccount; /* coherency counter */
314+ u16 bits; /* MPPC/MPPE control bits */
315+ u8 stateless; /* do we use stateless mode? */
316+ u8 nextflushed; /* set A bit in the next outgoing packet;
317+ used only by compressor*/
318+ u8 flushexpected; /* drop packets until A bit is received;
319+ used only by decompressor*/
320+ u8 *hist; /* MPPC history */
321+ u16 *hash; /* Hash table; used only by compressor */
322+ u16 histptr; /* history "cursor" */
323+ int unit;
324+ int debug;
325+ int mru;
326+ struct compstat stats;
327+};
328+
329+#define MPPE_HIST_LEN 8192 /* MPPC history size */
330+#define MPPE_MAX_CCOUNT 0x0FFF /* max. coherency counter value */
331+
332+#define MPPE_BIT_FLUSHED 0x80 /* bit A */
333+#define MPPE_BIT_RESET 0x40 /* bit B */
334+#define MPPE_BIT_COMP 0x20 /* bit C */
335+#define MPPE_BIT_ENCRYPTED 0x10 /* bit D */
336+
337+#define MPPE_SALT0 0xD1 /* values used in MPPE key derivation */
338+#define MPPE_SALT1 0x26 /* according to RFC3079 */
339+#define MPPE_SALT2 0x9E
340+
341+#define MPPE_CCOUNT(x) ((((x)[4] & 0x0f) << 8) + (x)[5])
342+#define MPPE_BITS(x) ((x)[4] & 0xf0)
343+#define MPPE_CTRLHI(x) ((((x)->ccount & 0xf00)>>8)|((x)->bits))
344+#define MPPE_CTRLLO(x) ((x)->ccount & 0xff)
345+
346+/*
347+ * Kernel Crypto API needs its arguments to be in kmalloc'd memory, not in the
348+ * module static data area. That means sha_pad needs to be kmalloc'd. It is done
349+ * in mppe_module_init(). This has been pointed out on 30th July 2004 by Oleg
350+ * Makarenko on pptpclient-devel mailing list.
351+ */
352+#define SHA1_PAD_SIZE 40
353+struct sha_pad {
354+ unsigned char sha_pad1[SHA1_PAD_SIZE];
355+ unsigned char sha_pad2[SHA1_PAD_SIZE];
356+};
357+static struct sha_pad *sha_pad;
358+
359+static inline void
360+setup_sg(struct scatterlist *sg, const void *address, unsigned int length)
361+{
362+ sg[0].page = virt_to_page(address);
363+ sg[0].offset = offset_in_page(address);
364+ sg[0].length = length;
365+}
366+
367+static inline void
368+arc4_setkey(struct ppp_mppe_state *state, const unsigned char *key,
369+ const unsigned int keylen)
370+{
371+ crypto_cipher_setkey(state->arc4_tfm, key, keylen);
372+}
373+
374+static inline void
375+arc4_encrypt(struct ppp_mppe_state *state, const unsigned char *in,
376+ const unsigned int len, unsigned char *out)
377+{
378+ struct scatterlist sgin[4], sgout[4];
379+
380+ setup_sg(sgin, in, len);
381+ setup_sg(sgout, out, len);
382+ crypto_cipher_encrypt(state->arc4_tfm, sgout, sgin, len);
383+}
384+
385+#define arc4_decrypt arc4_encrypt
386+
387+/*
388+ * Key Derivation, from RFC 3078, RFC 3079.
389+ * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
390+ */
391+static void
392+get_new_key_from_sha(struct ppp_mppe_state *state, unsigned char *interim_key)
393+{
394+ struct scatterlist sg[4];
395+
396+ setup_sg(&sg[0], state->master_key, state->keylen);
397+ setup_sg(&sg[1], sha_pad->sha_pad1, sizeof(sha_pad->sha_pad1));
398+ setup_sg(&sg[2], state->session_key, state->keylen);
399+ setup_sg(&sg[3], sha_pad->sha_pad2, sizeof(sha_pad->sha_pad2));
400+
401+ crypto_digest_digest (state->sha1_tfm, sg, 4, state->sha1_digest);
402+
403+ memcpy(interim_key, state->sha1_digest, state->keylen);
404+}
405+
406+static void
407+mppe_change_key(struct ppp_mppe_state *state, int initialize)
408+{
409+ unsigned char interim_key[MPPE_MAX_KEY_LEN];
410+
411+ get_new_key_from_sha(state, interim_key);
412+ if (initialize) {
413+ memcpy(state->session_key, interim_key, state->keylen);
414+ } else {
415+ arc4_setkey(state, interim_key, state->keylen);
416+ arc4_encrypt(state, interim_key, state->keylen, state->session_key);
417+ }
418+ if (state->keylen == 8) {
419+ if (state->bitkeylen == 40) {
420+ state->session_key[0] = MPPE_SALT0;
421+ state->session_key[1] = MPPE_SALT1;
422+ state->session_key[2] = MPPE_SALT2;
423+ } else {
424+ state->session_key[0] = MPPE_SALT0;
425+ }
426+ }
427+ arc4_setkey(state, state->session_key, state->keylen);
428+}
429+
430+/* increase 12-bit coherency counter */
431+static inline void
432+mppe_increase_ccount(struct ppp_mppe_state *state)
433+{
434+ state->ccount = (state->ccount + 1) & MPPE_MAX_CCOUNT;
435+ if (state->mppe) {
436+ if (state->stateless) {
437+ mppe_change_key(state, 0);
438+ state->nextflushed = 1;
439+ } else {
440+ if ((state->ccount & 0xff) == 0xff) {
441+ mppe_change_key(state, 0);
442+ }
443+ }
444+ }
445+}
446+
447+/* allocate space for a MPPE/MPPC (de)compressor. */
448+/* comp != 0 -> init compressor */
449+/* comp = 0 -> init decompressor */
450+static void *
451+mppe_alloc(unsigned char *options, int opt_len, int comp)
452+{
453+ struct ppp_mppe_state *state;
454+ unsigned int digestsize;
455+ u8* fname;
456+
457+ fname = comp ? "mppe_comp_alloc" : "mppe_decomp_alloc";
458+
459+ /*
460+ * Hack warning - additionally to the standard MPPC/MPPE configuration
461+ * options, pppd passes to the (de)copressor 8 or 16 byte session key.
462+ * Therefore options[1] contains MPPC/MPPE configuration option length
463+ * (CILEN_MPPE = 6), but the real options length, depending on the key
464+ * length, is 6+8 or 6+16.
465+ */
466+ if (opt_len < CILEN_MPPE) {
467+ printk(KERN_WARNING "%s: wrong options length: %u\n", fname, opt_len);
468+ return NULL;
469+ }
470+
471+ if (options[0] != CI_MPPE || options[1] != CILEN_MPPE ||
472+ (options[2] & ~MPPE_STATELESS) != 0 ||
473+ options[3] != 0 || options[4] != 0 ||
474+ (options[5] & ~(MPPE_128BIT|MPPE_56BIT|MPPE_40BIT|MPPE_MPPC)) != 0 ||
475+ (options[5] & (MPPE_128BIT|MPPE_56BIT|MPPE_40BIT|MPPE_MPPC)) == 0) {
476+ printk(KERN_WARNING "%s: options rejected: o[0]=%02x, o[1]=%02x, "
477+ "o[2]=%02x, o[3]=%02x, o[4]=%02x, o[5]=%02x\n", fname, options[0],
478+ options[1], options[2], options[3], options[4], options[5]);
479+ return NULL;
480+ }
481+
482+ state = (struct ppp_mppe_state *)kmalloc(sizeof(*state), GFP_KERNEL);
483+ if (state == NULL) {
484+ printk(KERN_ERR "%s: cannot allocate space for %scompressor\n", fname,
485+ comp ? "" : "de");
486+ return NULL;
487+ }
488+ memset(state, 0, sizeof(struct ppp_mppe_state));
489+
490+ state->mppc = options[5] & MPPE_MPPC; /* Do we use MPPC? */
491+ state->mppe = options[5] & (MPPE_128BIT | MPPE_56BIT |
492+ MPPE_40BIT); /* Do we use MPPE? */
493+
494+ if (state->mppc) {
495+ /* allocate MPPC history */
496+ state->hist = (u8*)vmalloc(2*MPPE_HIST_LEN*sizeof(u8));
497+ if (state->hist == NULL) {
498+ kfree(state);
499+ printk(KERN_ERR "%s: cannot allocate space for MPPC history\n",
500+ fname);
501+ return NULL;
502+ }
503+
504+ /* allocate hashtable for MPPC compressor */
505+ if (comp) {
506+ state->hash = (u16*)vmalloc(MPPE_HIST_LEN*sizeof(u16));
507+ if (state->hash == NULL) {
508+ vfree(state->hist);
509+ kfree(state);
510+ printk(KERN_ERR "%s: cannot allocate space for MPPC history\n",
511+ fname);
512+ return NULL;
513+ }
514+ }
515+ }
516+
517+ if (state->mppe) { /* specific for MPPE */
518+ /* Load ARC4 algorithm */
519+ state->arc4_tfm = crypto_alloc_tfm("arc4", 0);
520+ if (state->arc4_tfm == NULL) {
521+ if (state->mppc) {
522+ vfree(state->hash);
523+ if (comp)
524+ vfree(state->hist);
525+ }
526+ kfree(state);
527+ printk(KERN_ERR "%s: cannot load ARC4 module\n", fname);
528+ return NULL;
529+ }
530+
531+ /* Load SHA1 algorithm */
532+ state->sha1_tfm = crypto_alloc_tfm("sha1", 0);
533+ if (state->sha1_tfm == NULL) {
534+ crypto_free_tfm(state->arc4_tfm);
535+ if (state->mppc) {
536+ vfree(state->hash);
537+ if (comp)
538+ vfree(state->hist);
539+ }
540+ kfree(state);
541+ printk(KERN_ERR "%s: cannot load SHA1 module\n", fname);
542+ return NULL;
543+ }
544+
545+ digestsize = crypto_tfm_alg_digestsize(state->sha1_tfm);
546+ if (digestsize < MPPE_MAX_KEY_LEN) {
547+ crypto_free_tfm(state->sha1_tfm);
548+ crypto_free_tfm(state->arc4_tfm);
549+ if (state->mppc) {
550+ vfree(state->hash);
551+ if (comp)
552+ vfree(state->hist);
553+ }
554+ kfree(state);
555+ printk(KERN_ERR "%s: CryptoAPI SHA1 digest size too small\n", fname);
556+ }
557+
558+ state->sha1_digest = kmalloc(digestsize, GFP_KERNEL);
559+ if (!state->sha1_digest) {
560+ crypto_free_tfm(state->sha1_tfm);
561+ crypto_free_tfm(state->arc4_tfm);
562+ if (state->mppc) {
563+ vfree(state->hash);
564+ if (comp)
565+ vfree(state->hist);
566+ }
567+ kfree(state);
568+ printk(KERN_ERR "%s: cannot allocate space for SHA1 digest\n", fname);
569+ }
570+
571+ memcpy(state->master_key, options+CILEN_MPPE, MPPE_MAX_KEY_LEN);
572+ memcpy(state->session_key, state->master_key, MPPE_MAX_KEY_LEN);
573+ /* initial key generation is done in mppe_init() */
574+ }
575+
576+ MOD_INC_USE_COUNT;
577+
578+ return (void *) state;
579+}
580+
581+static void *
582+mppe_comp_alloc(unsigned char *options, int opt_len)
583+{
584+ return mppe_alloc(options, opt_len, 1);
585+}
586+
587+static void *
588+mppe_decomp_alloc(unsigned char *options, int opt_len)
589+{
590+ return mppe_alloc(options, opt_len, 0);
591+}
592+
593+/* cleanup the (de)compressor */
594+static void
595+mppe_comp_free(void *arg)
596+{
597+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
598+
599+ if (state != NULL) {
600+ if (state->mppe) {
601+ if (state->sha1_tfm != NULL)
602+ crypto_free_tfm(state->sha1_tfm);
603+ if (state->arc4_tfm != NULL)
604+ crypto_free_tfm(state->arc4_tfm);
605+ }
606+ if (state->hist != NULL)
607+ vfree(state->hist);
608+ if (state->hash != NULL)
609+ vfree(state->hash);
610+ kfree(state);
611+ }
612+
613+ MOD_DEC_USE_COUNT;
614+}
615+
616+/* init MPPC/MPPE (de)compresor */
617+/* comp != 0 -> init compressor */
618+/* comp = 0 -> init decompressor */
619+static int
620+mppe_init(void *arg, unsigned char *options, int opt_len, int unit,
621+ int hdrlen, int mru, int debug, int comp)
622+{
623+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
624+ u8* fname;
625+
626+ fname = comp ? "mppe_comp_init" : "mppe_decomp_init";
627+
628+ if (opt_len < CILEN_MPPE) {
629+ if (debug)
630+ printk(KERN_WARNING "%s: wrong options length: %u\n",
631+ fname, opt_len);
632+ return 0;
633+ }
634+
635+ if (options[0] != CI_MPPE || options[1] != CILEN_MPPE ||
636+ (options[2] & ~MPPE_STATELESS) != 0 ||
637+ options[3] != 0 || options[4] != 0 ||
638+ (options[5] & ~(MPPE_56BIT|MPPE_128BIT|MPPE_40BIT|MPPE_MPPC)) != 0 ||
639+ (options[5] & (MPPE_56BIT|MPPE_128BIT|MPPE_40BIT|MPPE_MPPC)) == 0) {
640+ if (debug)
641+ printk(KERN_WARNING "%s: options rejected: o[0]=%02x, o[1]=%02x, "
642+ "o[2]=%02x, o[3]=%02x, o[4]=%02x, o[5]=%02x\n", fname,
643+ options[0], options[1], options[2], options[3], options[4],
644+ options[5]);
645+ return 0;
646+ }
647+
648+ if ((options[5] & ~MPPE_MPPC) != MPPE_128BIT &&
649+ (options[5] & ~MPPE_MPPC) != MPPE_56BIT &&
650+ (options[5] & ~MPPE_MPPC) != MPPE_40BIT &&
651+ (options[5] & MPPE_MPPC) != MPPE_MPPC) {
652+ if (debug)
653+ printk(KERN_WARNING "%s: don't know what to do: o[5]=%02x\n",
654+ fname, options[5]);
655+ return 0;
656+ }
657+
658+ state->mppc = options[5] & MPPE_MPPC; /* Do we use MPPC? */
659+ state->mppe = options[5] & (MPPE_128BIT | MPPE_56BIT |
660+ MPPE_40BIT); /* Do we use MPPE? */
661+ state->stateless = options[2] & MPPE_STATELESS; /* Do we use stateless mode? */
662+
663+ switch (state->mppe) {
664+ case MPPE_40BIT: /* 40 bit key */
665+ state->keylen = 8;
666+ state->bitkeylen = 40;
667+ break;
668+ case MPPE_56BIT: /* 56 bit key */
669+ state->keylen = 8;
670+ state->bitkeylen = 56;
671+ break;
672+ case MPPE_128BIT: /* 128 bit key */
673+ state->keylen = 16;
674+ state->bitkeylen = 128;
675+ break;
676+ default:
677+ state->keylen = 0;
678+ state->bitkeylen = 0;
679+ }
680+
681+ state->ccount = MPPE_MAX_CCOUNT;
682+ state->bits = 0;
683+ state->unit = unit;
684+ state->debug = debug;
685+ state->histptr = MPPE_HIST_LEN;
686+ if (state->mppc) { /* reset history if MPPC was negotiated */
687+ memset(state->hist, 0, 2*MPPE_HIST_LEN*sizeof(u8));
688+ }
689+
690+ if (state->mppe) { /* generate initial session keys */
691+ mppe_change_key(state, 1);
692+ }
693+
694+ if (comp) { /* specific for compressor */
695+ state->nextflushed = 1;
696+ } else { /* specific for decompressor */
697+ state->mru = mru;
698+ state->flushexpected = 1;
699+ }
700+
701+ return 1;
702+}
703+
704+static int
705+mppe_comp_init(void *arg, unsigned char *options, int opt_len, int unit,
706+ int hdrlen, int debug)
707+{
708+ return mppe_init(arg, options, opt_len, unit, hdrlen, 0, debug, 1);
709+}
710+
711+
712+static int
713+mppe_decomp_init(void *arg, unsigned char *options, int opt_len, int unit,
714+ int hdrlen, int mru, int debug)
715+{
716+ return mppe_init(arg, options, opt_len, unit, hdrlen, mru, debug, 0);
717+}
718+
719+static void
720+mppe_comp_reset(void *arg)
721+{
722+ struct ppp_mppe_state *state = (struct ppp_mppe_state *)arg;
723+
724+ if (state->debug)
725+ printk(KERN_DEBUG "%s%d: resetting MPPC/MPPE compressor\n",
726+ __FUNCTION__, state->unit);
727+
728+ state->nextflushed = 1;
729+ if (state->mppe)
730+ arc4_setkey(state, state->session_key, state->keylen);
731+}
732+
733+static void
734+mppe_decomp_reset(void *arg)
735+{
736+ /* When MPPC/MPPE is in use, we shouldn't receive any CCP Reset-Ack.
737+ But when we receive such a packet, we just ignore it. */
738+ return;
739+}
740+
741+static void
742+mppe_stats(void *arg, struct compstat *stats)
743+{
744+ struct ppp_mppe_state *state = (struct ppp_mppe_state *)arg;
745+
746+ *stats = state->stats;
747+}
748+
749+/***************************/
750+/**** Compression stuff ****/
751+/***************************/
752+/* inserts 1 to 8 bits into the output buffer */
753+static inline void putbits8(u8 *buf, u32 val, const u32 n, u32 *i, u32 *l)
754+{
755+ buf += *i;
756+ if (*l >= n) {
757+ *l = (*l) - n;
758+ val <<= *l;
759+ *buf = *buf | (val & 0xff);
760+ if (*l == 0) {
761+ *l = 8;
762+ (*i)++;
763+ *(++buf) = 0;
764+ }
765+ } else {
766+ (*i)++;
767+ *l = 8 - n + (*l);
768+ val <<= *l;
769+ *buf = *buf | ((val >> 8) & 0xff);
770+ *(++buf) = val & 0xff;
771+ }
772+}
773+
774+/* inserts 9 to 16 bits into the output buffer */
775+static inline void putbits16(u8 *buf, u32 val, const u32 n, u32 *i, u32 *l)
776+{
777+ buf += *i;
778+ if (*l >= n - 8) {
779+ (*i)++;
780+ *l = 8 - n + (*l);
781+ val <<= *l;
782+ *buf = *buf | ((val >> 8) & 0xff);
783+ *(++buf) = val & 0xff;
784+ if (*l == 0) {
785+ *l = 8;
786+ (*i)++;
787+ *(++buf) = 0;
788+ }
789+ } else {
790+ (*i)++; (*i)++;
791+ *l = 16 - n + (*l);
792+ val <<= *l;
793+ *buf = *buf | ((val >> 16) & 0xff);
794+ *(++buf) = (val >> 8) & 0xff;
795+ *(++buf) = val & 0xff;
796+ }
797+}
798+
799+/* inserts 17 to 24 bits into the output buffer */
800+static inline void putbits24(u8 *buf, u32 val, const u32 n, u32 *i, u32 *l)
801+{
802+ buf += *i;
803+ if (*l >= n - 16) {
804+ (*i)++; (*i)++;
805+ *l = 16 - n + (*l);
806+ val <<= *l;
807+ *buf = *buf | ((val >> 16) & 0xff);
808+ *(++buf) = (val >> 8) & 0xff;
809+ *(++buf) = val & 0xff;
810+ if (*l == 0) {
811+ *l = 8;
812+ (*i)++;
813+ *(++buf) = 0;
814+ }
815+ } else {
816+ (*i)++; (*i)++; (*i)++;
817+ *l = 24 - n + (*l);
818+ val <<= *l;
819+ *buf = *buf | ((val >> 24) & 0xff);
820+ *(++buf) = (val >> 16) & 0xff;
821+ *(++buf) = (val >> 8) & 0xff;
822+ *(++buf) = val & 0xff;
823+ }
824+}
825+
826+static int
827+mppc_compress(struct ppp_mppe_state *state, unsigned char *ibuf,
828+ unsigned char *obuf, int isize, int osize)
829+{
830+ u32 olen, off, len, idx, i, l;
831+ u8 *hist, *sbuf, *p, *q, *r, *s;
832+
833+ /*
834+ At this point, to avoid possible buffer overflow caused by packet
835+ expansion during/after compression, we should make sure that
836+ osize >= (((isize*9)/8)+1)+2, but we don't do that because in
837+ ppp_generic.c we simply allocate bigger obuf.
838+
839+ Maximum MPPC packet expansion is 12.5%. This is the worst case when
840+ all octets in the input buffer are >= 0x80 and we cannot find any
841+ repeated tokens. Additionally we have to reserve 2 bytes for MPPE/MPPC
842+ status bits and coherency counter.
843+ */
844+
845+ hist = state->hist + MPPE_HIST_LEN;
846+ /* check if there is enough room at the end of the history */
847+ if (state->histptr + isize >= 2*MPPE_HIST_LEN) {
848+ state->bits |= MPPE_BIT_RESET;
849+ state->histptr = MPPE_HIST_LEN;
850+ memcpy(state->hist, hist, MPPE_HIST_LEN);
851+ }
852+ /* add packet to the history; isize must be <= MPPE_HIST_LEN */
853+ sbuf = state->hist + state->histptr;
854+ memcpy(sbuf, ibuf, isize);
855+ state->histptr += isize;
856+
857+ /* compress data */
858+ r = sbuf + isize;
859+ *obuf = olen = i = 0;
860+ l = 8;
861+ while (i < isize - 2) {
862+ s = q = sbuf + i;
863+ idx = ((40543*((((s[0]<<4)^s[1])<<4)^s[2]))>>4) & 0x1fff;
864+ p = hist + state->hash[idx];
865+ state->hash[idx] = (u16) (s - hist);
866+ off = s - p;
867+ if (off > MPPE_HIST_LEN - 1 || off < 1 || *p++ != *s++ || *p++ != *s++ ||
868+ *p++ != *s++) {
869+ /* no match found; encode literal byte */
870+ if (ibuf[i] < 0x80) { /* literal byte < 0x80 */
871+ putbits8(obuf, (u32) ibuf[i], 8, &olen, &l);
872+ } else { /* literal byte >= 0x80 */
873+ putbits16(obuf, (u32) (0x100|(ibuf[i]&0x7f)), 9, &olen, &l);
874+ }
875+ ++i;
876+ continue;
877+ }
878+ if (r - q >= 64) {
879+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
880+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
881+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
882+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
883+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
884+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
885+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
886+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
887+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
888+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
889+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
890+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
891+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
892+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
893+ *p++ != *s++ || *p++ != *s++ || *p++ != *s++ || *p++ != *s++ ||
894+ *p++ != *s++;
895+ if (s - q == 64) {
896+ p--; s--;
897+ while((*p++ == *s++) && (s < r) && (p < q));
898+ }
899+ } else {
900+ while((*p++ == *s++) && (s < r) && (p < q));
901+ }
902+ len = s - q - 1;
903+ i += len;
904+
905+ /* at least 3 character match found; code data */
906+ /* encode offset */
907+ if (off < 64) { /* 10-bit offset; 0 <= offset < 64 */
908+ putbits16(obuf, 0x3c0|off, 10, &olen, &l);
909+ } else if (off < 320) { /* 12-bit offset; 64 <= offset < 320 */
910+ putbits16(obuf, 0xe00|(off-64), 12, &olen, &l);
911+ } else if (off < 8192) { /* 16-bit offset; 320 <= offset < 8192 */
912+ putbits16(obuf, 0xc000|(off-320), 16, &olen, &l);
913+ } else {
914+ /* This shouldn't happen; we return 0 what means "packet expands",
915+ and we send packet uncompressed. */
916+ if (state->debug)
917+ printk(KERN_DEBUG "%s%d: wrong offset value: %d\n",
918+ __FUNCTION__, state->unit, off);
919+ return 0;
920+ }
921+ /* encode length of match */
922+ if (len < 4) { /* length = 3 */
923+ putbits8(obuf, 0, 1, &olen, &l);
924+ } else if (len < 8) { /* 4 <= length < 8 */
925+ putbits8(obuf, 0x08|(len&0x03), 4, &olen, &l);
926+ } else if (len < 16) { /* 8 <= length < 16 */
927+ putbits8(obuf, 0x30|(len&0x07), 6, &olen, &l);
928+ } else if (len < 32) { /* 16 <= length < 32 */
929+ putbits8(obuf, 0xe0|(len&0x0f), 8, &olen, &l);
930+ } else if (len < 64) { /* 32 <= length < 64 */
931+ putbits16(obuf, 0x3c0|(len&0x1f), 10, &olen, &l);
932+ } else if (len < 128) { /* 64 <= length < 128 */
933+ putbits16(obuf, 0xf80|(len&0x3f), 12, &olen, &l);
934+ } else if (len < 256) { /* 128 <= length < 256 */
935+ putbits16(obuf, 0x3f00|(len&0x7f), 14, &olen, &l);
936+ } else if (len < 512) { /* 256 <= length < 512 */
937+ putbits16(obuf, 0xfe00|(len&0xff), 16, &olen, &l);
938+ } else if (len < 1024) { /* 512 <= length < 1024 */
939+ putbits24(obuf, 0x3fc00|(len&0x1ff), 18, &olen, &l);
940+ } else if (len < 2048) { /* 1024 <= length < 2048 */
941+ putbits24(obuf, 0xff800|(len&0x3ff), 20, &olen, &l);
942+ } else if (len < 4096) { /* 2048 <= length < 4096 */
943+ putbits24(obuf, 0x3ff000|(len&0x7ff), 22, &olen, &l);
944+ } else if (len < 8192) { /* 4096 <= length < 8192 */
945+ putbits24(obuf, 0xffe000|(len&0xfff), 24, &olen, &l);
946+ } else {
947+ /* This shouldn't happen; we return 0 what means "packet expands",
948+ and send packet uncompressed. */
949+ if (state->debug)
950+ printk(KERN_DEBUG "%s%d: wrong length of match value: %d\n",
951+ __FUNCTION__, state->unit, len);
952+ return 0;
953+ }
954+ }
955+
956+ /* Add remaining octets to the output */
957+ while(isize - i > 0) {
958+ if (ibuf[i] < 0x80) { /* literal byte < 0x80 */
959+ putbits8(obuf, (u32) ibuf[i++], 8, &olen, &l);
960+ } else { /* literal byte >= 0x80 */
961+ putbits16(obuf, (u32) (0x100|(ibuf[i++]&0x7f)), 9, &olen, &l);
962+ }
963+ }
964+ /* Reset unused bits of the last output octet */
965+ if ((l != 0) && (l != 8)) {
966+ putbits8(obuf, 0, l, &olen, &l);
967+ }
968+
969+ return (int) olen;
970+}
971+
972+int
973+mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf,
974+ int isize, int osize)
975+{
976+ struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
977+ int proto, olen, complen, off;
978+ unsigned char *wptr;
979+
980+ /* Check that the protocol is in the range we handle. */
981+ proto = PPP_PROTOCOL(ibuf);
982+ if (proto < 0x0021 || proto > 0x00fa)
983+ return 0;
984+
985+ wptr = obuf;
986+ /* Copy over the PPP header */
987+ wptr[0] = PPP_ADDRESS(ibuf);
988+ wptr[1] = PPP_CONTROL(ibuf);
989+ wptr[2] = PPP_COMP >> 8;
990+ wptr[3] = PPP_COMP;
991+ wptr += PPP_HDRLEN + (MPPE_OVHD / 2); /* Leave two octets for MPPE/MPPC bits */
992+
993+ /*
994+ * In ver. 0.99 protocol field was compressed. Deflate and BSD compress
995+ * do PFC before actual compression, RCF2118 and RFC3078 are not precise
996+ * on this topic so I decided to do PFC. Unfortunately this change caused
997+ * incompatibility with older/other MPPE/MPPC modules. I have received
998+ * a lot of complaints from unexperienced users so I have decided to revert
999+ * to previous state, i.e. the protocol field is sent uncompressed now.
1000+ * Although this may be changed in the future.
1001+ *
1002+ * Receiving side (mppe_decompress()) still accepts packets with compressed
1003+ * and uncompressed protocol field so you shouldn't get "Unsupported protocol
1004+ * 0x2145 received" messages anymore.
1005+ */
1006+ //off = (proto > 0xff) ? 2 : 3; /* PFC - skip first protocol byte if 0 */
1007+ off = 2;
1008+
1009+ ibuf += off;
1010+
1011+ mppe_increase_ccount(state);
1012+
1013+ if (state->nextflushed) {
1014+ state->bits |= MPPE_BIT_FLUSHED;
1015+ state->nextflushed = 0;
1016+ if (state->mppe && !state->stateless) {
1017+ /*
1018+ * If this is the flag packet, the key has been already changed in
1019+ * mppe_increase_ccount() so we dont't do it once again.
1020+ */
1021+ if ((state->ccount & 0xff) != 0xff) {
1022+ arc4_setkey(state, state->session_key, state->keylen);
1023+ }
1024+ }
1025+ if (state->mppc) { /* reset history */
1026+ state->bits |= MPPE_BIT_RESET;
1027+ state->histptr = MPPE_HIST_LEN;
1028+ memset(state->hist + MPPE_HIST_LEN, 0, MPPE_HIST_LEN*sizeof(u8));
1029+ }
1030+ }
1031+
1032+ if (state->mppc && !state->mppe) { /* Do only compression */
1033+ complen = mppc_compress(state, ibuf, wptr, isize - off,
1034+ osize - PPP_HDRLEN - (MPPE_OVHD / 2));
1035+ /*
1036+ * TODO: Implement an heuristics to handle packet expansion in a smart
1037+ * way. Now, when a packet expands, we send it as uncompressed and
1038+ * when next packet is sent we have to reset compressor's history.
1039+ * Maybe it would be better to send such packet as compressed in order
1040+ * to keep history's continuity.
1041+ */
1042+ if ((complen > isize) || (complen > osize - PPP_HDRLEN) ||
1043+ (complen == 0)) {
1044+ /* packet expands */
1045+ state->nextflushed = 1;
1046+ memcpy(wptr, ibuf, isize - off);
1047+ olen = isize - (off - 2) + MPPE_OVHD;
1048+ (state->stats).inc_bytes += olen;
1049+ (state->stats).inc_packets++;
1050+ } else {
1051+ state->bits |= MPPE_BIT_COMP;
1052+ olen = complen + PPP_HDRLEN + (MPPE_OVHD / 2);
1053+ (state->stats).comp_bytes += olen;
1054+ (state->stats).comp_packets++;
1055+ }
1056+ } else { /* Do encryption with or without compression */
1057+ state->bits |= MPPE_BIT_ENCRYPTED;
1058+ if (!state->mppc && state->mppe) { /* Do only encryption */
1059+ /* read from ibuf, write to wptr, adjust for PPP_HDRLEN */
1060+ arc4_encrypt(state, ibuf, isize - off, wptr);
1061+ olen = isize - (off - 2) + MPPE_OVHD;
1062+ (state->stats).inc_bytes += olen;
1063+ (state->stats).inc_packets++;
1064+ } else { /* Do compression and then encryption - RFC3078 */
1065+ complen = mppc_compress(state, ibuf, wptr, isize - off,
1066+ osize - PPP_HDRLEN - (MPPE_OVHD / 2));
1067+ /*
1068+ * TODO: Implement an heuristics to handle packet expansion in a smart
1069+ * way. Now, when a packet expands, we send it as uncompressed and
1070+ * when next packet is sent we have to reset compressor's history.
1071+ * Maybe it would be good to send such packet as compressed in order
1072+ * to keep history's continuity.
1073+ */
1074+ if ((complen > isize) || (complen > osize - PPP_HDRLEN) ||
1075+ (complen == 0)) {
1076+ /* packet expands */
1077+ state->nextflushed = 1;
1078+ arc4_encrypt(state, ibuf, isize - off, wptr);
1079+ olen = isize - (off - 2) + MPPE_OVHD;
1080+ (state->stats).inc_bytes += olen;
1081+ (state->stats).inc_packets++;
1082+ } else {
1083+ state->bits |= MPPE_BIT_COMP;
1084+ /* Hack warning !!! RC4 implementation which we use does
1085+ encryption "in place" - it means that input and output
1086+ buffers can be *the same* memory area. Therefore we don't
1087+ need to use a temporary buffer. But be careful - other
1088+ implementations don't have to be so nice.
1089+ I used to use ibuf as temporary buffer here, but it led
1090+ packet sniffers into error. Thanks to Wilfried Weissmann
1091+ for pointing that. */
1092+ arc4_encrypt(state, wptr, complen, wptr);
1093+ olen = complen + PPP_HDRLEN + (MPPE_OVHD / 2);
1094+ (state->stats).comp_bytes += olen;
1095+ (state->stats).comp_packets++;
1096+ }
1097+ }
1098+ }
1099+
1100+ /* write status bits and coherency counter into the output buffer */
1101+ wptr = obuf + PPP_HDRLEN;
1102+ wptr[0] = MPPE_CTRLHI(state);
1103+ wptr[1] = MPPE_CTRLLO(state);
1104+
1105+ state->bits = 0;
1106+
1107+ (state->stats).unc_bytes += isize;
1108+ (state->stats).unc_packets++;
1109+
1110+ return olen;
1111+}
1112+
1113+/***************************/
1114+/*** Decompression stuff ***/
1115+/***************************/
1116+static inline u32 getbits(const u8 *buf, const u32 n, u32 *i, u32 *l)
1117+{
1118+ static const u32 m[] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
1119+ u32 res, ol;
1120+
1121+ ol = *l;
1122+ if (*l >= n) {
1123+ *l = (*l) - n;
1124+ res = (buf[*i] & m[ol]) >> (*l);
1125+ if (*l == 0) {
1126+ *l = 8;
1127+ (*i)++;
1128+ }
1129+ } else {
1130+ *l = 8 - n + (*l);
1131+ res = (buf[(*i)++] & m[ol]) << 8;
1132+ res = (res | buf[*i]) >> (*l);
1133+ }
1134+
1135+ return res;
1136+}
1137+
1138+static inline u32 getbyte(const u8 *buf, const u32 i, const u32 l)
1139+{
1140+ if (l == 8) {
1141+ return buf[i];
1142+ } else {
1143+ return (((buf[i] << 8) | buf[i+1]) >> l) & 0xff;
1144+ }
1145+}
1146+
1147+static inline void lamecopy(u8 *dst, u8 *src, u32 len)
1148+{
1149+ while (len--)
1150+ *dst++ = *src++;
1151+}
1152+
1153+static int
1154+mppc_decompress(struct ppp_mppe_state *state, unsigned char *ibuf,
1155+ unsigned char *obuf, int isize, int osize)
1156+{
1157+ u32 olen, off, len, bits, val, sig, i, l;
1158+ u8 *history, *s;
1159+
1160+ history = state->hist + state->histptr;
1161+ olen = len = i = 0;
1162+ l = 8;
1163+ bits = isize * 8;
1164+ while (bits >= 8) {
1165+ val = getbyte(ibuf, i++, l);
1166+ if (val < 0x80) { /* literal byte < 0x80 */
1167+ if (state->histptr < 2*MPPE_HIST_LEN) {
1168+ /* copy uncompressed byte to the history */
1169+ (state->hist)[(state->histptr)++] = (u8) val;
1170+ } else {
1171+ /* buffer overflow; drop packet */
1172+ if (state->debug)
1173+ printk(KERN_ERR "%s%d: trying to write outside history "
1174+ "buffer\n", __FUNCTION__, state->unit);
1175+ return DECOMP_ERROR;
1176+ }
1177+ olen++;
1178+ bits -= 8;
1179+ continue;
1180+ }
1181+
1182+ sig = val & 0xc0;
1183+ if (sig == 0x80) { /* literal byte >= 0x80 */
1184+ if (state->histptr < 2*MPPE_HIST_LEN) {
1185+ /* copy uncompressed byte to the history */
1186+ (state->hist)[(state->histptr)++] =
1187+ (u8) (0x80|((val&0x3f)<<1)|getbits(ibuf, 1 , &i ,&l));
1188+ } else {
1189+ /* buffer overflow; drop packet */
1190+ if (state->debug)
1191+ printk(KERN_ERR "%s%d: trying to write outside history "
1192+ "buffer\n", __FUNCTION__, state->unit);
1193+ return DECOMP_ERROR;
1194+ }
1195+ olen++;
1196+ bits -= 9;
1197+ continue;
1198+ }
1199+
1200+ /* Not a literal byte so it must be an (offset,length) pair */
1201+ /* decode offset */
1202+ sig = val & 0xf0;
1203+ if (sig == 0xf0) { /* 10-bit offset; 0 <= offset < 64 */
1204+ off = (((val&0x0f)<<2)|getbits(ibuf, 2 , &i ,&l));
1205+ bits -= 10;
1206+ } else {
1207+ if (sig == 0xe0) { /* 12-bit offset; 64 <= offset < 320 */
1208+ off = ((((val&0x0f)<<4)|getbits(ibuf, 4 , &i ,&l))+64);
1209+ bits -= 12;
1210+ } else {
1211+ if ((sig&0xe0) == 0xc0) {/* 16-bit offset; 320 <= offset < 8192 */
1212+ off = ((((val&0x1f)<<8)|getbyte(ibuf, i++, l))+320);
1213+ bits -= 16;
1214+ if (off > MPPE_HIST_LEN - 1) {
1215+ if (state->debug)
1216+ printk(KERN_DEBUG "%s%d: too big offset value: %d\n",
1217+ __FUNCTION__, state->unit, off);
1218+ return DECOMP_ERROR;
1219+ }
1220+ } else { /* this shouldn't happen */
1221+ if (state->debug)
1222+ printk(KERN_DEBUG "%s%d: cannot decode offset value\n",
1223+ __FUNCTION__, state->unit);
1224+ return DECOMP_ERROR;
1225+ }
1226+ }
1227+ }
1228+ /* decode length of match */
1229+ val = getbyte(ibuf, i, l);
1230+ if ((val & 0x80) == 0x00) { /* len = 3 */
1231+ len = 3;
1232+ bits--;
1233+ getbits(ibuf, 1 , &i ,&l);
1234+ } else if ((val & 0xc0) == 0x80) { /* 4 <= len < 8 */
1235+ len = 0x04 | ((val>>4) & 0x03);
1236+ bits -= 4;
1237+ getbits(ibuf, 4 , &i ,&l);
1238+ } else if ((val & 0xe0) == 0xc0) { /* 8 <= len < 16 */
1239+ len = 0x08 | ((val>>2) & 0x07);
1240+ bits -= 6;
1241+ getbits(ibuf, 6 , &i ,&l);
1242+ } else if ((val & 0xf0) == 0xe0) { /* 16 <= len < 32 */
1243+ len = 0x10 | (val & 0x0f);
1244+ bits -= 8;
1245+ i++;
1246+ } else {
1247+ bits -= 8;
1248+ val = (val << 8) | getbyte(ibuf, ++i, l);
1249+ if ((val & 0xf800) == 0xf000) { /* 32 <= len < 64 */
1250+ len = 0x0020 | ((val >> 6) & 0x001f);
1251+ bits -= 2;
1252+ getbits(ibuf, 2 , &i ,&l);
1253+ } else if ((val & 0xfc00) == 0xf800) { /* 64 <= len < 128 */
1254+ len = 0x0040 | ((val >> 4) & 0x003f);
1255+ bits -= 4;
1256+ getbits(ibuf, 4 , &i ,&l);
1257+ } else if ((val & 0xfe00) == 0xfc00) { /* 128 <= len < 256 */
1258+ len = 0x0080 | ((val >> 2) & 0x007f);
1259+ bits -= 6;
1260+ getbits(ibuf, 6 , &i ,&l);
1261+ } else if ((val & 0xff00) == 0xfe00) { /* 256 <= len < 512 */
1262+ len = 0x0100 | (val & 0x00ff);
1263+ bits -= 8;
1264+ i++;
1265+ } else {
1266+ bits -= 8;
1267+ val = (val << 8) | getbyte(ibuf, ++i, l);
1268+ if ((val & 0xff8000) == 0xff0000) { /* 512 <= len < 1024 */
1269+ len = 0x000200 | ((val >> 6) & 0x0001ff);
1270+ bits -= 2;
1271+ getbits(ibuf, 2 , &i ,&l);
1272+ } else if ((val & 0xffc000) == 0xff8000) {/* 1024 <= len < 2048 */
1273+ len = 0x000400 | ((val >> 4) & 0x0003ff);
1274+ bits -= 4;
1275+ getbits(ibuf, 4 , &i ,&l);
1276+ } else if ((val & 0xffe000) == 0xffc000) {/* 2048 <= len < 4096 */
1277+ len = 0x000800 | ((val >> 2) & 0x0007ff);
1278+ bits -= 6;
1279+ getbits(ibuf, 6 , &i ,&l);
1280+ } else if ((val & 0xfff000) == 0xffe000) {/* 4096 <= len < 8192 */
1281+ len = 0x001000 | (val & 0x000fff);
1282+ bits -= 8;
1283+ i++;
1284+ } else { /* this shouldn't happen */
1285+ if (state->debug)
1286+ printk(KERN_DEBUG "%s%d: wrong length code: 0x%X\n",
1287+ __FUNCTION__, state->unit, val);
1288+ return DECOMP_ERROR;
1289+ }
1290+ }
1291+ }
1292+ s = state->hist + state->histptr;
1293+ state->histptr += len;
1294+ olen += len;
1295+ if (state->histptr < 2*MPPE_HIST_LEN) {
1296+ /* copy uncompressed bytes to the history */
1297+
1298+ /* In some cases len may be greater than off. It means that memory
1299+ * areas pointed by s and s-off overlap. I had used memmove() here
1300+ * because I thought that it acts as libc's version. Unfortunately,
1301+ * I was wrong. :-) I got strange errors sometimes. Wilfried suggested
1302+ * using of byte by byte copying here and strange errors disappeared.
1303+ */
1304+ lamecopy(s, s - off, len);
1305+ } else {
1306+ /* buffer overflow; drop packet */
1307+ if (state->debug)
1308+ printk(KERN_ERR "%s%d: trying to write outside history "
1309+ "buffer\n", __FUNCTION__, state->unit);
1310+ return DECOMP_ERROR;
1311+ }
1312+ }
1313+
1314+ /* Do PFC decompression */
1315+ len = olen;
1316+ if ((history[0] & 0x01) != 0) {
1317+ obuf[0] = 0;
1318+ obuf++;
1319+ len++;
1320+ }
1321+
1322+ if (len <= osize) {
1323+ /* copy uncompressed packet to the output buffer */
1324+ memcpy(obuf, history, olen);
1325+ } else {
1326+ /* buffer overflow; drop packet */
1327+ if (state->debug)
1328+ printk(KERN_ERR "%s%d: too big uncompressed packet: %d\n",
1329+ __FUNCTION__, state->unit, len + (PPP_HDRLEN / 2));
1330+ return DECOMP_ERROR;
1331+ }
1332+
1333+ return (int) len;
1334+}
1335+
1336+int
1337+mppe_decompress(void *arg, unsigned char *ibuf, int isize,
1338+ unsigned char *obuf, int osize)
1339+{
1340+ struct ppp_mppe_state *state = (struct ppp_mppe_state *)arg;
1341+ int seq, bits, uncomplen;
1342+
1343+ if (isize <= PPP_HDRLEN + MPPE_OVHD) {
1344+ if (state->debug) {
1345+ printk(KERN_DEBUG "%s%d: short packet (len=%d)\n", __FUNCTION__,
1346+ state->unit, isize);
1347+ }
1348+ return DECOMP_ERROR;
1349+ }
1350+
1351+ /* Get coherency counter and control bits from input buffer */
1352+ seq = MPPE_CCOUNT(ibuf);
1353+ bits = MPPE_BITS(ibuf);
1354+
1355+ if (state->stateless) {
1356+ /* RFC 3078, sec 8.1. */
1357+ mppe_increase_ccount(state);
1358+ if ((seq != state->ccount) && state->debug)
1359+ printk(KERN_DEBUG "%s%d: bad sequence number: %d, expected: %d\n",
1360+ __FUNCTION__, state->unit, seq, state->ccount);
1361+ while (seq != state->ccount)
1362+ mppe_increase_ccount(state);
1363+ } else {
1364+ /* RFC 3078, sec 8.2. */
1365+ if (state->flushexpected) { /* discard state */
1366+ if ((bits & MPPE_BIT_FLUSHED)) { /* we received expected FLUSH bit */
1367+ while (seq != state->ccount)
1368+ mppe_increase_ccount(state);
1369+ state->flushexpected = 0;
1370+ } else /* drop packet*/
1371+ return DECOMP_ERROR;
1372+ } else { /* normal state */
1373+ mppe_increase_ccount(state);
1374+ if (seq != state->ccount) {
1375+ /* Packet loss detected, enter the discard state. */
1376+ if (state->debug)
1377+ printk(KERN_DEBUG "%s%d: bad sequence number: %d, expected: %d\n",
1378+ __FUNCTION__, state->unit, seq, state->ccount);
1379+ state->flushexpected = 1;
1380+ return DECOMP_ERROR;
1381+ }
1382+ }
1383+ if (state->mppe && (bits & MPPE_BIT_FLUSHED)) {
1384+ arc4_setkey(state, state->session_key, state->keylen);
1385+ }
1386+ }
1387+
1388+ if (state->mppc && (bits & (MPPE_BIT_FLUSHED | MPPE_BIT_RESET))) {
1389+ state->histptr = MPPE_HIST_LEN;
1390+ if ((bits & MPPE_BIT_FLUSHED)) {
1391+ memset(state->hist + MPPE_HIST_LEN, 0, MPPE_HIST_LEN*sizeof(u8));
1392+ } else
1393+ if ((bits & MPPE_BIT_RESET)) {
1394+ memcpy(state->hist, state->hist + MPPE_HIST_LEN, MPPE_HIST_LEN);
1395+ }
1396+ }
1397+
1398+ /* Fill in the first part of the PPP header. The protocol field
1399+ comes from the decompressed data. */
1400+ obuf[0] = PPP_ADDRESS(ibuf);
1401+ obuf[1] = PPP_CONTROL(ibuf);
1402+ obuf += PPP_HDRLEN / 2;
1403+
1404+ if (state->mppe) { /* process encrypted packet */
1405+ if ((bits & MPPE_BIT_ENCRYPTED)) {
1406+ /* OK, packet encrypted, so decrypt it */
1407+ if (state->mppc && (bits & MPPE_BIT_COMP)) {
1408+ /* Hack warning !!! RC4 implementation which we use does
1409+ decryption "in place" - it means that input and output
1410+ buffers can be *the same* memory area. Therefore we don't
1411+ need to use a temporary buffer. But be careful - other
1412+ implementations don't have to be so nice. */
1413+ arc4_decrypt(state, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2), isize -
1414+ PPP_HDRLEN - (MPPE_OVHD / 2), ibuf + PPP_HDRLEN +
1415+ (MPPE_OVHD / 2));
1416+ uncomplen = mppc_decompress(state, ibuf + PPP_HDRLEN +
1417+ (MPPE_OVHD / 2), obuf, isize -
1418+ PPP_HDRLEN - (MPPE_OVHD / 2),
1419+ osize - (PPP_HDRLEN / 2));
1420+ if (uncomplen == DECOMP_ERROR) {
1421+ state->flushexpected = 1;
1422+ return DECOMP_ERROR;
1423+ }
1424+ uncomplen += PPP_HDRLEN / 2;
1425+ (state->stats).comp_bytes += isize;
1426+ (state->stats).comp_packets++;
1427+ } else {
1428+ uncomplen = isize - MPPE_OVHD;
1429+ /* Decrypt the first byte in order to check if it is
1430+ compressed or uncompressed protocol field */
1431+ arc4_decrypt(state, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2), 1, obuf);
1432+ /* Do PFC decompression */
1433+ if ((obuf[0] & 0x01) != 0) {
1434+ obuf[1] = obuf[0];
1435+ obuf[0] = 0;
1436+ obuf++;
1437+ uncomplen++;
1438+ }
1439+ /* And finally, decrypt the rest of the frame. */
1440+ arc4_decrypt(state, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2) + 1,
1441+ isize - PPP_HDRLEN - (MPPE_OVHD / 2) - 1, obuf + 1);
1442+ (state->stats).inc_bytes += isize;
1443+ (state->stats).inc_packets++;
1444+ }
1445+ } else { /* this shouldn't happen */
1446+ if (state->debug)
1447+ printk(KERN_ERR "%s%d: encryption negotiated but not an "
1448+ "encrypted packet received\n", __FUNCTION__, state->unit);
1449+ mppe_change_key(state, 0);
1450+ state->flushexpected = 1;
1451+ return DECOMP_ERROR;
1452+ }
1453+ } else {
1454+ if (state->mppc) { /* no MPPE, only MPPC */
1455+ if ((bits & MPPE_BIT_COMP)) {
1456+ uncomplen = mppc_decompress(state, ibuf + PPP_HDRLEN +
1457+ (MPPE_OVHD / 2), obuf, isize -
1458+ PPP_HDRLEN - (MPPE_OVHD / 2),
1459+ osize - (PPP_HDRLEN / 2));
1460+ if (uncomplen == DECOMP_ERROR) {
1461+ state->flushexpected = 1;
1462+ return DECOMP_ERROR;
1463+ }
1464+ uncomplen += PPP_HDRLEN / 2;
1465+ (state->stats).comp_bytes += isize;
1466+ (state->stats).comp_packets++;
1467+ } else {
1468+ memcpy(obuf, ibuf + PPP_HDRLEN + (MPPE_OVHD / 2), isize -
1469+ PPP_HDRLEN - (MPPE_OVHD / 2));
1470+ uncomplen = isize - MPPE_OVHD;
1471+ (state->stats).inc_bytes += isize;
1472+ (state->stats).inc_packets++;
1473+ }
1474+ } else { /* this shouldn't happen */
1475+ if (state->debug)
1476+ printk(KERN_ERR "%s%d: error - not an MPPC or MPPE frame "
1477+ "received\n", __FUNCTION__, state->unit);
1478+ state->flushexpected = 1;
1479+ return DECOMP_ERROR;
1480+ }
1481+ }
1482+
1483+ (state->stats).unc_bytes += uncomplen;
1484+ (state->stats).unc_packets++;
1485+
1486+ return uncomplen;
1487+}
1488+
1489+
1490+/************************************************************
1491+ * Module interface table
1492+ ************************************************************/
1493+
1494+/* These are in ppp_generic.c */
1495+extern int ppp_register_compressor (struct compressor *cp);
1496+extern void ppp_unregister_compressor (struct compressor *cp);
1497+
1498+/*
1499+ * Functions exported to ppp_generic.c.
1500+ *
1501+ * In case of MPPC/MPPE there is no need to process incompressible data
1502+ * because such a data is sent in MPPC/MPPE frame. Therefore the (*incomp)
1503+ * callback function isn't needed.
1504+ */
1505+struct compressor ppp_mppe = {
1506+ CI_MPPE, /* compress_proto */
1507+ mppe_comp_alloc, /* comp_alloc */
1508+ mppe_comp_free, /* comp_free */
1509+ mppe_comp_init, /* comp_init */
1510+ mppe_comp_reset, /* comp_reset */
1511+ mppe_compress, /* compress */
1512+ mppe_stats, /* comp_stat */
1513+ mppe_decomp_alloc, /* decomp_alloc */
1514+ mppe_comp_free, /* decomp_free */
1515+ mppe_decomp_init, /* decomp_init */
1516+ mppe_decomp_reset, /* decomp_reset */
1517+ mppe_decompress, /* decompress */
1518+ NULL, /* incomp */
1519+ mppe_stats, /* decomp_stat */
1520+};
1521+
1522+/************************************************************
1523+ * Module support routines
1524+ ************************************************************/
1525+
1526+int __init mppe_module_init(void)
1527+{
1528+ int answer;
1529+
1530+ /* When the module is compiled into kernel, it is initialized before
1531+ * CryptoAPI. Therefore the code below reports that there is no crypto
1532+ * stuff in the kernel. Marlon de Boer who has pointed out the problem,
1533+ * has sent also a message to CryptoAPI developers, so maybe in the future
1534+ * the code will be uncommented.
1535+ *
1536+ if (!(crypto_alg_available("arc4", 0) && crypto_alg_available("sha1", 0))) {
1537+ printk(KERN_ERR "Kernel doesn't provide ARC4 and/or SHA1 algorithms "
1538+ "required by MPPE/MPPC. Check CryptoAPI configuration.\n");
1539+ return -ENODEV;
1540+ }
1541+ */
1542+
1543+ /* Allocate space for SHAPad1, SHAPad2 and ... */
1544+ sha_pad = kmalloc(sizeof(struct sha_pad), GFP_KERNEL);
1545+ if (sha_pad == NULL)
1546+ return -ENOMEM;
1547+ /* ... initialize them */
1548+ memset(sha_pad->sha_pad1, 0x00, sizeof(sha_pad->sha_pad1));
1549+ memset(sha_pad->sha_pad2, 0xf2, sizeof(sha_pad->sha_pad2));
1550+
1551+ answer = ppp_register_compressor(&ppp_mppe);
1552+ if (answer == 0) {
1553+ printk(KERN_INFO "MPPE/MPPC encryption/compression module registered\n");
1554+ }
1555+ return answer;
1556+}
1557+
1558+void __exit mppe_module_cleanup(void)
1559+{
1560+ kfree(sha_pad);
1561+ ppp_unregister_compressor(&ppp_mppe);
1562+ printk(KERN_INFO "MPPE/MPPC encryption/compression module unregistered\n");
1563+}
1564+
1565+module_init(mppe_module_init);
1566+module_exit(mppe_module_cleanup);
1567+
1568+MODULE_AUTHOR("Jan Dubiec <jdx@slackware.pl>");
1569+MODULE_DESCRIPTION("MPPE/MPPC encryption/compression module for Linux");
1570+MODULE_LICENSE("Dual BSD/GPL");
1571--- a/include/linux/ppp-comp.h
1572+++ b/include/linux/ppp-comp.h
1573@@ -28,7 +28,7 @@
1574  */
1575 
1576 /*
1577- * ==FILEVERSION 980319==
1578+ * ==FILEVERSION 20040509==
1579  *
1580  * NOTE TO MAINTAINERS:
1581  * If you modify this file at all, please set the above date.
1582@@ -78,7 +78,7 @@ struct compressor {
1583 
1584     /* Compress a packet */
1585     int (*compress) (void *state, unsigned char *rptr,
1586- unsigned char *obuf, int isize, int osize);
1587+ unsigned char *obuf, int isize, int osize);
1588 
1589     /* Return compression statistics */
1590     void (*comp_stat) (void *state, struct compstat *stats);
1591@@ -99,7 +99,7 @@ struct compressor {
1592 
1593     /* Decompress a packet. */
1594     int (*decompress) (void *state, unsigned char *ibuf, int isize,
1595- unsigned char *obuf, int osize);
1596+ unsigned char *obuf, int osize);
1597 
1598     /* Update state for an incompressible packet received */
1599     void (*incomp) (void *state, unsigned char *ibuf, int icnt);
1600@@ -187,6 +187,42 @@ struct compressor {
1601 #define DEFLATE_CHK_SEQUENCE 0
1602 
1603 /*
1604+ * Definitions for MPPE/MPPC.
1605+ */
1606+
1607+#define CI_MPPE 18 /* config option for MPPE */
1608+#define CILEN_MPPE 6 /* length of config option */
1609+
1610+#define MPPE_OVHD 4 /* MPPE overhead */
1611+#define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */
1612+
1613+#define MPPE_STATELESS 0x01 /* configuration bit H */
1614+#define MPPE_40BIT 0x20 /* configuration bit L */
1615+#define MPPE_56BIT 0x80 /* configuration bit M */
1616+#define MPPE_128BIT 0x40 /* configuration bit S */
1617+#define MPPE_MPPC 0x01 /* configuration bit C */
1618+
1619+/*
1620+ * Definitions for Stac LZS.
1621+ */
1622+
1623+#define CI_LZS 17 /* config option for Stac LZS */
1624+#define CILEN_LZS 5 /* length of config option */
1625+
1626+#define LZS_OVHD 4 /* max. LZS overhead */
1627+#define LZS_HIST_LEN 2048 /* LZS history size */
1628+#define LZS_MAX_CCOUNT 0x0FFF /* max. coherency counter value */
1629+
1630+#define LZS_MODE_NONE 0
1631+#define LZS_MODE_LCB 1
1632+#define LZS_MODE_CRC 2
1633+#define LZS_MODE_SEQ 3
1634+#define LZS_MODE_EXT 4
1635+
1636+#define LZS_EXT_BIT_FLUSHED 0x80 /* bit A */
1637+#define LZS_EXT_BIT_COMP 0x20 /* bit C */
1638+
1639+/*
1640  * Definitions for other, as yet unsupported, compression methods.
1641  */
1642 
1643

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