bcca5847d5
other "system" header files. Also help the deprecation of lockmgr.h by making it a sub-include of sys/lock.h and removing sys/lockmgr.h form kernel .c files. Sort sys/*.h includes where possible in affected files. OK'ed by: bde (with reservations)
1115 lines
29 KiB
C
1115 lines
29 KiB
C
/* Because this code is derived from the 4.3BSD compress source:
|
|
*
|
|
*
|
|
* Copyright (c) 1985, 1986 The Regents of the University of California.
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* All rights reserved.
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*
|
|
* This code is derived from software contributed to Berkeley by
|
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* James A. Woods, derived from original work by Spencer Thomas
|
|
* and Joseph Orost.
|
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*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
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* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
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* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
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*/
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|
|
|
/*
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|
* This version is for use with mbufs on BSD-derived systems.
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*
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* $FreeBSD$
|
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*/
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|
|
|
#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/mutex.h>
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|
#include <net/ppp_defs.h>
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|
|
#define PACKETPTR struct mbuf *
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#include <net/ppp_comp.h>
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|
/*
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* PPP "BSD compress" compression
|
|
* The differences between this compression and the classic BSD LZW
|
|
* source are obvious from the requirement that the classic code worked
|
|
* with files while this handles arbitrarily long streams that
|
|
* are broken into packets. They are:
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|
*
|
|
* When the code size expands, a block of junk is not emitted by
|
|
* the compressor and not expected by the decompressor.
|
|
*
|
|
* New codes are not necessarily assigned every time an old
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|
* code is output by the compressor. This is because a packet
|
|
* end forces a code to be emitted, but does not imply that a
|
|
* new sequence has been seen.
|
|
*
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|
* The compression ratio is checked at the first end of a packet
|
|
* after the appropriate gap. Besides simplifying and speeding
|
|
* things up, this makes it more likely that the transmitter
|
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* and receiver will agree when the dictionary is cleared when
|
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* compression is not going well.
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|
*/
|
|
|
|
/*
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|
* A dictionary for doing BSD compress.
|
|
*/
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|
struct bsd_db {
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|
int totlen; /* length of this structure */
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|
u_int hsize; /* size of the hash table */
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|
u_char hshift; /* used in hash function */
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|
u_char n_bits; /* current bits/code */
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|
u_char maxbits;
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|
u_char debug;
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|
u_char unit;
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|
u_int16_t seqno; /* sequence # of next packet */
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|
u_int hdrlen; /* header length to preallocate */
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|
u_int mru;
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|
u_int maxmaxcode; /* largest valid code */
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|
u_int max_ent; /* largest code in use */
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|
u_int in_count; /* uncompressed bytes, aged */
|
|
u_int bytes_out; /* compressed bytes, aged */
|
|
u_int ratio; /* recent compression ratio */
|
|
u_int checkpoint; /* when to next check the ratio */
|
|
u_int clear_count; /* times dictionary cleared */
|
|
u_int incomp_count; /* incompressible packets */
|
|
u_int incomp_bytes; /* incompressible bytes */
|
|
u_int uncomp_count; /* uncompressed packets */
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|
u_int uncomp_bytes; /* uncompressed bytes */
|
|
u_int comp_count; /* compressed packets */
|
|
u_int comp_bytes; /* compressed bytes */
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|
u_int16_t *lens; /* array of lengths of codes */
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|
struct bsd_dict {
|
|
union { /* hash value */
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|
u_int32_t fcode;
|
|
struct {
|
|
#if BYTE_ORDER == LITTLE_ENDIAN
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u_int16_t prefix; /* preceding code */
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|
u_char suffix; /* last character of new code */
|
|
u_char pad;
|
|
#else
|
|
u_char pad;
|
|
u_char suffix; /* last character of new code */
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|
u_int16_t prefix; /* preceding code */
|
|
#endif
|
|
} hs;
|
|
} f;
|
|
u_int16_t codem1; /* output of hash table -1 */
|
|
u_int16_t cptr; /* map code to hash table entry */
|
|
} dict[1];
|
|
};
|
|
|
|
#define BSD_OVHD 2 /* BSD compress overhead/packet */
|
|
#define BSD_INIT_BITS BSD_MIN_BITS
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|
|
|
static void bsd_clear __P((struct bsd_db *db));
|
|
static int bsd_check __P((struct bsd_db *db));
|
|
static void *bsd_alloc __P((u_char *options, int opt_len, int decomp));
|
|
static int bsd_init __P((struct bsd_db *db, u_char *options, int opt_len,
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|
int unit, int hdrlen, int mru, int debug,
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|
int decomp));
|
|
static void *bsd_comp_alloc __P((u_char *options, int opt_len));
|
|
static void *bsd_decomp_alloc __P((u_char *options, int opt_len));
|
|
static void bsd_free __P((void *state));
|
|
static int bsd_comp_init __P((void *state, u_char *options, int opt_len,
|
|
int unit, int hdrlen, int debug));
|
|
static int bsd_decomp_init __P((void *state, u_char *options, int opt_len,
|
|
int unit, int hdrlen, int mru, int debug));
|
|
static int bsd_compress __P((void *state, struct mbuf **mret,
|
|
struct mbuf *mp, int slen, int maxolen));
|
|
static void bsd_incomp __P((void *state, struct mbuf *dmsg));
|
|
static int bsd_decompress __P((void *state, struct mbuf *cmp,
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|
struct mbuf **dmpp));
|
|
static void bsd_reset __P((void *state));
|
|
static void bsd_comp_stats __P((void *state, struct compstat *stats));
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|
|
|
/*
|
|
* Procedures exported to if_ppp.c.
|
|
*/
|
|
struct compressor ppp_bsd_compress = {
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|
CI_BSD_COMPRESS, /* compress_proto */
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|
bsd_comp_alloc, /* comp_alloc */
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|
bsd_free, /* comp_free */
|
|
bsd_comp_init, /* comp_init */
|
|
bsd_reset, /* comp_reset */
|
|
bsd_compress, /* compress */
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|
bsd_comp_stats, /* comp_stat */
|
|
bsd_decomp_alloc, /* decomp_alloc */
|
|
bsd_free, /* decomp_free */
|
|
bsd_decomp_init, /* decomp_init */
|
|
bsd_reset, /* decomp_reset */
|
|
bsd_decompress, /* decompress */
|
|
bsd_incomp, /* incomp */
|
|
bsd_comp_stats, /* decomp_stat */
|
|
};
|
|
|
|
/*
|
|
* the next two codes should not be changed lightly, as they must not
|
|
* lie within the contiguous general code space.
|
|
*/
|
|
#define CLEAR 256 /* table clear output code */
|
|
#define FIRST 257 /* first free entry */
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|
#define LAST 255
|
|
|
|
#define MAXCODE(b) ((1 << (b)) - 1)
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|
#define BADCODEM1 MAXCODE(BSD_MAX_BITS)
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|
|
|
#define BSD_HASH(prefix,suffix,hshift) ((((u_int32_t)(suffix)) << (hshift)) \
|
|
^ (u_int32_t)(prefix))
|
|
#define BSD_KEY(prefix,suffix) ((((u_int32_t)(suffix)) << 16) \
|
|
+ (u_int32_t)(prefix))
|
|
|
|
#define CHECK_GAP 10000 /* Ratio check interval */
|
|
|
|
#define RATIO_SCALE_LOG 8
|
|
#define RATIO_SCALE (1<<RATIO_SCALE_LOG)
|
|
#define RATIO_MAX (0x7fffffff>>RATIO_SCALE_LOG)
|
|
|
|
/*
|
|
* clear the dictionary
|
|
*/
|
|
static void
|
|
bsd_clear(db)
|
|
struct bsd_db *db;
|
|
{
|
|
db->clear_count++;
|
|
db->max_ent = FIRST-1;
|
|
db->n_bits = BSD_INIT_BITS;
|
|
db->ratio = 0;
|
|
db->bytes_out = 0;
|
|
db->in_count = 0;
|
|
db->checkpoint = CHECK_GAP;
|
|
}
|
|
|
|
/*
|
|
* If the dictionary is full, then see if it is time to reset it.
|
|
*
|
|
* Compute the compression ratio using fixed-point arithmetic
|
|
* with 8 fractional bits.
|
|
*
|
|
* Since we have an infinite stream instead of a single file,
|
|
* watch only the local compression ratio.
|
|
*
|
|
* Since both peers must reset the dictionary at the same time even in
|
|
* the absence of CLEAR codes (while packets are incompressible), they
|
|
* must compute the same ratio.
|
|
*/
|
|
static int /* 1=output CLEAR */
|
|
bsd_check(db)
|
|
struct bsd_db *db;
|
|
{
|
|
u_int new_ratio;
|
|
|
|
if (db->in_count >= db->checkpoint) {
|
|
/* age the ratio by limiting the size of the counts */
|
|
if (db->in_count >= RATIO_MAX
|
|
|| db->bytes_out >= RATIO_MAX) {
|
|
db->in_count -= db->in_count/4;
|
|
db->bytes_out -= db->bytes_out/4;
|
|
}
|
|
|
|
db->checkpoint = db->in_count + CHECK_GAP;
|
|
|
|
if (db->max_ent >= db->maxmaxcode) {
|
|
/* Reset the dictionary only if the ratio is worse,
|
|
* or if it looks as if it has been poisoned
|
|
* by incompressible data.
|
|
*
|
|
* This does not overflow, because
|
|
* db->in_count <= RATIO_MAX.
|
|
*/
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|
new_ratio = db->in_count << RATIO_SCALE_LOG;
|
|
if (db->bytes_out != 0)
|
|
new_ratio /= db->bytes_out;
|
|
|
|
if (new_ratio < db->ratio || new_ratio < 1 * RATIO_SCALE) {
|
|
bsd_clear(db);
|
|
return 1;
|
|
}
|
|
db->ratio = new_ratio;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Return statistics.
|
|
*/
|
|
static void
|
|
bsd_comp_stats(state, stats)
|
|
void *state;
|
|
struct compstat *stats;
|
|
{
|
|
struct bsd_db *db = (struct bsd_db *) state;
|
|
u_int out;
|
|
|
|
stats->unc_bytes = db->uncomp_bytes;
|
|
stats->unc_packets = db->uncomp_count;
|
|
stats->comp_bytes = db->comp_bytes;
|
|
stats->comp_packets = db->comp_count;
|
|
stats->inc_bytes = db->incomp_bytes;
|
|
stats->inc_packets = db->incomp_count;
|
|
stats->ratio = db->in_count;
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|
out = db->bytes_out;
|
|
if (stats->ratio <= 0x7fffff)
|
|
stats->ratio <<= 8;
|
|
else
|
|
out >>= 8;
|
|
if (out != 0)
|
|
stats->ratio /= out;
|
|
}
|
|
|
|
/*
|
|
* Reset state, as on a CCP ResetReq.
|
|
*/
|
|
static void
|
|
bsd_reset(state)
|
|
void *state;
|
|
{
|
|
struct bsd_db *db = (struct bsd_db *) state;
|
|
|
|
db->seqno = 0;
|
|
bsd_clear(db);
|
|
db->clear_count = 0;
|
|
}
|
|
|
|
/*
|
|
* Allocate space for a (de) compressor.
|
|
*/
|
|
static void *
|
|
bsd_alloc(options, opt_len, decomp)
|
|
u_char *options;
|
|
int opt_len, decomp;
|
|
{
|
|
int bits;
|
|
u_int newlen, hsize, hshift, maxmaxcode;
|
|
struct bsd_db *db;
|
|
|
|
if (opt_len < CILEN_BSD_COMPRESS || options[0] != CI_BSD_COMPRESS
|
|
|| options[1] != CILEN_BSD_COMPRESS
|
|
|| BSD_VERSION(options[2]) != BSD_CURRENT_VERSION)
|
|
return NULL;
|
|
bits = BSD_NBITS(options[2]);
|
|
switch (bits) {
|
|
case 9: /* needs 82152 for both directions */
|
|
case 10: /* needs 84144 */
|
|
case 11: /* needs 88240 */
|
|
case 12: /* needs 96432 */
|
|
hsize = 5003;
|
|
hshift = 4;
|
|
break;
|
|
case 13: /* needs 176784 */
|
|
hsize = 9001;
|
|
hshift = 5;
|
|
break;
|
|
case 14: /* needs 353744 */
|
|
hsize = 18013;
|
|
hshift = 6;
|
|
break;
|
|
case 15: /* needs 691440 */
|
|
hsize = 35023;
|
|
hshift = 7;
|
|
break;
|
|
case 16: /* needs 1366160--far too much, */
|
|
/* hsize = 69001; */ /* and 69001 is too big for cptr */
|
|
/* hshift = 8; */ /* in struct bsd_db */
|
|
/* break; */
|
|
default:
|
|
return NULL;
|
|
}
|
|
|
|
maxmaxcode = MAXCODE(bits);
|
|
newlen = sizeof(*db) + (hsize-1) * (sizeof(db->dict[0]));
|
|
MALLOC(db, struct bsd_db *, newlen, M_DEVBUF, M_NOWAIT);
|
|
if (!db)
|
|
return NULL;
|
|
bzero(db, sizeof(*db) - sizeof(db->dict));
|
|
|
|
if (!decomp) {
|
|
db->lens = NULL;
|
|
} else {
|
|
MALLOC(db->lens, u_int16_t *, (maxmaxcode+1) * sizeof(db->lens[0]),
|
|
M_DEVBUF, M_NOWAIT);
|
|
if (!db->lens) {
|
|
FREE(db, M_DEVBUF);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
db->totlen = newlen;
|
|
db->hsize = hsize;
|
|
db->hshift = hshift;
|
|
db->maxmaxcode = maxmaxcode;
|
|
db->maxbits = bits;
|
|
|
|
return (void *) db;
|
|
}
|
|
|
|
static void
|
|
bsd_free(state)
|
|
void *state;
|
|
{
|
|
struct bsd_db *db = (struct bsd_db *) state;
|
|
|
|
if (db->lens)
|
|
FREE(db->lens, M_DEVBUF);
|
|
FREE(db, M_DEVBUF);
|
|
}
|
|
|
|
static void *
|
|
bsd_comp_alloc(options, opt_len)
|
|
u_char *options;
|
|
int opt_len;
|
|
{
|
|
return bsd_alloc(options, opt_len, 0);
|
|
}
|
|
|
|
static void *
|
|
bsd_decomp_alloc(options, opt_len)
|
|
u_char *options;
|
|
int opt_len;
|
|
{
|
|
return bsd_alloc(options, opt_len, 1);
|
|
}
|
|
|
|
/*
|
|
* Initialize the database.
|
|
*/
|
|
static int
|
|
bsd_init(db, options, opt_len, unit, hdrlen, mru, debug, decomp)
|
|
struct bsd_db *db;
|
|
u_char *options;
|
|
int opt_len, unit, hdrlen, mru, debug, decomp;
|
|
{
|
|
int i;
|
|
|
|
if (opt_len < CILEN_BSD_COMPRESS || options[0] != CI_BSD_COMPRESS
|
|
|| options[1] != CILEN_BSD_COMPRESS
|
|
|| BSD_VERSION(options[2]) != BSD_CURRENT_VERSION
|
|
|| BSD_NBITS(options[2]) != db->maxbits
|
|
|| (decomp && db->lens == NULL))
|
|
return 0;
|
|
|
|
if (decomp) {
|
|
i = LAST+1;
|
|
while (i != 0)
|
|
db->lens[--i] = 1;
|
|
}
|
|
i = db->hsize;
|
|
while (i != 0) {
|
|
db->dict[--i].codem1 = BADCODEM1;
|
|
db->dict[i].cptr = 0;
|
|
}
|
|
|
|
db->unit = unit;
|
|
db->hdrlen = hdrlen;
|
|
db->mru = mru;
|
|
#ifndef DEBUG
|
|
if (debug)
|
|
#endif
|
|
db->debug = 1;
|
|
|
|
bsd_reset(db);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
bsd_comp_init(state, options, opt_len, unit, hdrlen, debug)
|
|
void *state;
|
|
u_char *options;
|
|
int opt_len, unit, hdrlen, debug;
|
|
{
|
|
return bsd_init((struct bsd_db *) state, options, opt_len,
|
|
unit, hdrlen, 0, debug, 0);
|
|
}
|
|
|
|
static int
|
|
bsd_decomp_init(state, options, opt_len, unit, hdrlen, mru, debug)
|
|
void *state;
|
|
u_char *options;
|
|
int opt_len, unit, hdrlen, mru, debug;
|
|
{
|
|
return bsd_init((struct bsd_db *) state, options, opt_len,
|
|
unit, hdrlen, mru, debug, 1);
|
|
}
|
|
|
|
|
|
/*
|
|
* compress a packet
|
|
* One change from the BSD compress command is that when the
|
|
* code size expands, we do not output a bunch of padding.
|
|
*/
|
|
int /* new slen */
|
|
bsd_compress(state, mret, mp, slen, maxolen)
|
|
void *state;
|
|
struct mbuf **mret; /* return compressed mbuf chain here */
|
|
struct mbuf *mp; /* from here */
|
|
int slen; /* uncompressed length */
|
|
int maxolen; /* max compressed length */
|
|
{
|
|
struct bsd_db *db = (struct bsd_db *) state;
|
|
int hshift = db->hshift;
|
|
u_int max_ent = db->max_ent;
|
|
u_int n_bits = db->n_bits;
|
|
u_int bitno = 32;
|
|
u_int32_t accm = 0, fcode;
|
|
struct bsd_dict *dictp;
|
|
u_char c;
|
|
int hval, disp, ent, ilen;
|
|
u_char *rptr, *wptr;
|
|
u_char *cp_end;
|
|
int olen;
|
|
struct mbuf *m;
|
|
|
|
#define PUTBYTE(v) { \
|
|
++olen; \
|
|
if (wptr) { \
|
|
*wptr++ = (v); \
|
|
if (wptr >= cp_end) { \
|
|
m->m_len = wptr - mtod(m, u_char *); \
|
|
MGET(m->m_next, M_DONTWAIT, MT_DATA); \
|
|
m = m->m_next; \
|
|
if (m) { \
|
|
m->m_len = 0; \
|
|
if (maxolen - olen > MLEN) \
|
|
MCLGET(m, M_DONTWAIT); \
|
|
wptr = mtod(m, u_char *); \
|
|
cp_end = wptr + M_TRAILINGSPACE(m); \
|
|
} else \
|
|
wptr = NULL; \
|
|
} \
|
|
} \
|
|
}
|
|
|
|
#define OUTPUT(ent) { \
|
|
bitno -= n_bits; \
|
|
accm |= ((ent) << bitno); \
|
|
do { \
|
|
PUTBYTE(accm >> 24); \
|
|
accm <<= 8; \
|
|
bitno += 8; \
|
|
} while (bitno <= 24); \
|
|
}
|
|
|
|
/*
|
|
* If the protocol is not in the range we're interested in,
|
|
* just return without compressing the packet. If it is,
|
|
* the protocol becomes the first byte to compress.
|
|
*/
|
|
rptr = mtod(mp, u_char *);
|
|
ent = PPP_PROTOCOL(rptr);
|
|
if (ent < 0x21 || ent > 0xf9) {
|
|
*mret = NULL;
|
|
return slen;
|
|
}
|
|
|
|
/* Don't generate compressed packets which are larger than
|
|
the uncompressed packet. */
|
|
if (maxolen > slen)
|
|
maxolen = slen;
|
|
|
|
/* Allocate one mbuf to start with. */
|
|
MGET(m, M_DONTWAIT, MT_DATA);
|
|
*mret = m;
|
|
if (m != NULL) {
|
|
m->m_len = 0;
|
|
if (maxolen + db->hdrlen > MLEN)
|
|
MCLGET(m, M_DONTWAIT);
|
|
m->m_data += db->hdrlen;
|
|
wptr = mtod(m, u_char *);
|
|
cp_end = wptr + M_TRAILINGSPACE(m);
|
|
} else
|
|
wptr = cp_end = NULL;
|
|
|
|
/*
|
|
* Copy the PPP header over, changing the protocol,
|
|
* and install the 2-byte packet sequence number.
|
|
*/
|
|
if (wptr) {
|
|
*wptr++ = PPP_ADDRESS(rptr); /* assumes the ppp header is */
|
|
*wptr++ = PPP_CONTROL(rptr); /* all in one mbuf */
|
|
*wptr++ = 0; /* change the protocol */
|
|
*wptr++ = PPP_COMP;
|
|
*wptr++ = db->seqno >> 8;
|
|
*wptr++ = db->seqno;
|
|
}
|
|
++db->seqno;
|
|
|
|
olen = 0;
|
|
rptr += PPP_HDRLEN;
|
|
slen = mp->m_len - PPP_HDRLEN;
|
|
ilen = slen + 1;
|
|
for (;;) {
|
|
if (slen <= 0) {
|
|
mp = mp->m_next;
|
|
if (!mp)
|
|
break;
|
|
rptr = mtod(mp, u_char *);
|
|
slen = mp->m_len;
|
|
if (!slen)
|
|
continue; /* handle 0-length buffers */
|
|
ilen += slen;
|
|
}
|
|
|
|
slen--;
|
|
c = *rptr++;
|
|
fcode = BSD_KEY(ent, c);
|
|
hval = BSD_HASH(ent, c, hshift);
|
|
dictp = &db->dict[hval];
|
|
|
|
/* Validate and then check the entry. */
|
|
if (dictp->codem1 >= max_ent)
|
|
goto nomatch;
|
|
if (dictp->f.fcode == fcode) {
|
|
ent = dictp->codem1+1;
|
|
continue; /* found (prefix,suffix) */
|
|
}
|
|
|
|
/* continue probing until a match or invalid entry */
|
|
disp = (hval == 0) ? 1 : hval;
|
|
do {
|
|
hval += disp;
|
|
if (hval >= db->hsize)
|
|
hval -= db->hsize;
|
|
dictp = &db->dict[hval];
|
|
if (dictp->codem1 >= max_ent)
|
|
goto nomatch;
|
|
} while (dictp->f.fcode != fcode);
|
|
ent = dictp->codem1 + 1; /* finally found (prefix,suffix) */
|
|
continue;
|
|
|
|
nomatch:
|
|
OUTPUT(ent); /* output the prefix */
|
|
|
|
/* code -> hashtable */
|
|
if (max_ent < db->maxmaxcode) {
|
|
struct bsd_dict *dictp2;
|
|
/* expand code size if needed */
|
|
if (max_ent >= MAXCODE(n_bits))
|
|
db->n_bits = ++n_bits;
|
|
|
|
/* Invalidate old hash table entry using
|
|
* this code, and then take it over.
|
|
*/
|
|
dictp2 = &db->dict[max_ent+1];
|
|
if (db->dict[dictp2->cptr].codem1 == max_ent)
|
|
db->dict[dictp2->cptr].codem1 = BADCODEM1;
|
|
dictp2->cptr = hval;
|
|
dictp->codem1 = max_ent;
|
|
dictp->f.fcode = fcode;
|
|
|
|
db->max_ent = ++max_ent;
|
|
}
|
|
ent = c;
|
|
}
|
|
|
|
OUTPUT(ent); /* output the last code */
|
|
db->bytes_out += olen;
|
|
db->in_count += ilen;
|
|
if (bitno < 32)
|
|
++db->bytes_out; /* count complete bytes */
|
|
|
|
if (bsd_check(db))
|
|
OUTPUT(CLEAR); /* do not count the CLEAR */
|
|
|
|
/*
|
|
* Pad dribble bits of last code with ones.
|
|
* Do not emit a completely useless byte of ones.
|
|
*/
|
|
if (bitno != 32)
|
|
PUTBYTE((accm | (0xff << (bitno-8))) >> 24);
|
|
|
|
if (m != NULL) {
|
|
m->m_len = wptr - mtod(m, u_char *);
|
|
m->m_next = NULL;
|
|
}
|
|
|
|
/*
|
|
* Increase code size if we would have without the packet
|
|
* boundary and as the decompressor will.
|
|
*/
|
|
if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode)
|
|
db->n_bits++;
|
|
|
|
db->uncomp_bytes += ilen;
|
|
++db->uncomp_count;
|
|
if (olen + PPP_HDRLEN + BSD_OVHD > maxolen) {
|
|
/* throw away the compressed stuff if it is longer than uncompressed */
|
|
if (*mret != NULL) {
|
|
m_freem(*mret);
|
|
*mret = NULL;
|
|
}
|
|
++db->incomp_count;
|
|
db->incomp_bytes += ilen;
|
|
} else {
|
|
++db->comp_count;
|
|
db->comp_bytes += olen + BSD_OVHD;
|
|
}
|
|
|
|
return olen + PPP_HDRLEN + BSD_OVHD;
|
|
#undef OUTPUT
|
|
#undef PUTBYTE
|
|
}
|
|
|
|
|
|
/*
|
|
* Update the "BSD Compress" dictionary on the receiver for
|
|
* incompressible data by pretending to compress the incoming data.
|
|
*/
|
|
static void
|
|
bsd_incomp(state, dmsg)
|
|
void *state;
|
|
struct mbuf *dmsg;
|
|
{
|
|
struct bsd_db *db = (struct bsd_db *) state;
|
|
u_int hshift = db->hshift;
|
|
u_int max_ent = db->max_ent;
|
|
u_int n_bits = db->n_bits;
|
|
struct bsd_dict *dictp;
|
|
u_int32_t fcode;
|
|
u_char c;
|
|
u_int32_t hval, disp;
|
|
int slen, ilen;
|
|
u_int bitno = 7;
|
|
u_char *rptr;
|
|
u_int ent;
|
|
|
|
/*
|
|
* If the protocol is not in the range we're interested in,
|
|
* just return without looking at the packet. If it is,
|
|
* the protocol becomes the first byte to "compress".
|
|
*/
|
|
rptr = mtod(dmsg, u_char *);
|
|
ent = PPP_PROTOCOL(rptr);
|
|
if (ent < 0x21 || ent > 0xf9)
|
|
return;
|
|
|
|
db->seqno++;
|
|
ilen = 1; /* count the protocol as 1 byte */
|
|
rptr += PPP_HDRLEN;
|
|
slen = dmsg->m_len - PPP_HDRLEN;
|
|
for (;;) {
|
|
if (slen <= 0) {
|
|
dmsg = dmsg->m_next;
|
|
if (!dmsg)
|
|
break;
|
|
rptr = mtod(dmsg, u_char *);
|
|
slen = dmsg->m_len;
|
|
continue;
|
|
}
|
|
ilen += slen;
|
|
|
|
do {
|
|
c = *rptr++;
|
|
fcode = BSD_KEY(ent, c);
|
|
hval = BSD_HASH(ent, c, hshift);
|
|
dictp = &db->dict[hval];
|
|
|
|
/* validate and then check the entry */
|
|
if (dictp->codem1 >= max_ent)
|
|
goto nomatch;
|
|
if (dictp->f.fcode == fcode) {
|
|
ent = dictp->codem1+1;
|
|
continue; /* found (prefix,suffix) */
|
|
}
|
|
|
|
/* continue probing until a match or invalid entry */
|
|
disp = (hval == 0) ? 1 : hval;
|
|
do {
|
|
hval += disp;
|
|
if (hval >= db->hsize)
|
|
hval -= db->hsize;
|
|
dictp = &db->dict[hval];
|
|
if (dictp->codem1 >= max_ent)
|
|
goto nomatch;
|
|
} while (dictp->f.fcode != fcode);
|
|
ent = dictp->codem1+1;
|
|
continue; /* finally found (prefix,suffix) */
|
|
|
|
nomatch: /* output (count) the prefix */
|
|
bitno += n_bits;
|
|
|
|
/* code -> hashtable */
|
|
if (max_ent < db->maxmaxcode) {
|
|
struct bsd_dict *dictp2;
|
|
/* expand code size if needed */
|
|
if (max_ent >= MAXCODE(n_bits))
|
|
db->n_bits = ++n_bits;
|
|
|
|
/* Invalidate previous hash table entry
|
|
* assigned this code, and then take it over.
|
|
*/
|
|
dictp2 = &db->dict[max_ent+1];
|
|
if (db->dict[dictp2->cptr].codem1 == max_ent)
|
|
db->dict[dictp2->cptr].codem1 = BADCODEM1;
|
|
dictp2->cptr = hval;
|
|
dictp->codem1 = max_ent;
|
|
dictp->f.fcode = fcode;
|
|
|
|
db->max_ent = ++max_ent;
|
|
db->lens[max_ent] = db->lens[ent]+1;
|
|
}
|
|
ent = c;
|
|
} while (--slen != 0);
|
|
}
|
|
bitno += n_bits; /* output (count) the last code */
|
|
db->bytes_out += bitno/8;
|
|
db->in_count += ilen;
|
|
(void)bsd_check(db);
|
|
|
|
++db->incomp_count;
|
|
db->incomp_bytes += ilen;
|
|
++db->uncomp_count;
|
|
db->uncomp_bytes += ilen;
|
|
|
|
/* Increase code size if we would have without the packet
|
|
* boundary and as the decompressor will.
|
|
*/
|
|
if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode)
|
|
db->n_bits++;
|
|
}
|
|
|
|
|
|
/*
|
|
* Decompress "BSD Compress".
|
|
*
|
|
* Because of patent problems, we return DECOMP_ERROR for errors
|
|
* found by inspecting the input data and for system problems, but
|
|
* DECOMP_FATALERROR for any errors which could possibly be said to
|
|
* be being detected "after" decompression. For DECOMP_ERROR,
|
|
* we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
|
|
* infringing a patent of Motorola's if we do, so we take CCP down
|
|
* instead.
|
|
*
|
|
* Given that the frame has the correct sequence number and a good FCS,
|
|
* errors such as invalid codes in the input most likely indicate a
|
|
* bug, so we return DECOMP_FATALERROR for them in order to turn off
|
|
* compression, even though they are detected by inspecting the input.
|
|
*/
|
|
int
|
|
bsd_decompress(state, cmp, dmpp)
|
|
void *state;
|
|
struct mbuf *cmp, **dmpp;
|
|
{
|
|
struct bsd_db *db = (struct bsd_db *) state;
|
|
u_int max_ent = db->max_ent;
|
|
u_int32_t accm = 0;
|
|
u_int bitno = 32; /* 1st valid bit in accm */
|
|
u_int n_bits = db->n_bits;
|
|
u_int tgtbitno = 32-n_bits; /* bitno when we have a code */
|
|
struct bsd_dict *dictp;
|
|
int explen, i, seq, len;
|
|
u_int incode, oldcode, finchar;
|
|
u_char *p, *rptr, *wptr;
|
|
struct mbuf *m, *dmp, *mret;
|
|
int adrs, ctrl, ilen;
|
|
int space, codelen, extra;
|
|
|
|
/*
|
|
* Save the address/control from the PPP header
|
|
* and then get the sequence number.
|
|
*/
|
|
*dmpp = NULL;
|
|
rptr = mtod(cmp, u_char *);
|
|
adrs = PPP_ADDRESS(rptr);
|
|
ctrl = PPP_CONTROL(rptr);
|
|
rptr += PPP_HDRLEN;
|
|
len = cmp->m_len - PPP_HDRLEN;
|
|
seq = 0;
|
|
for (i = 0; i < 2; ++i) {
|
|
while (len <= 0) {
|
|
cmp = cmp->m_next;
|
|
if (cmp == NULL)
|
|
return DECOMP_ERROR;
|
|
rptr = mtod(cmp, u_char *);
|
|
len = cmp->m_len;
|
|
}
|
|
seq = (seq << 8) + *rptr++;
|
|
--len;
|
|
}
|
|
|
|
/*
|
|
* Check the sequence number and give up if it differs from
|
|
* the value we're expecting.
|
|
*/
|
|
if (seq != db->seqno) {
|
|
if (db->debug)
|
|
printf("bsd_decomp%d: bad sequence # %d, expected %d\n",
|
|
db->unit, seq, db->seqno - 1);
|
|
return DECOMP_ERROR;
|
|
}
|
|
++db->seqno;
|
|
|
|
/*
|
|
* Allocate one mbuf to start with.
|
|
*/
|
|
MGETHDR(dmp, M_DONTWAIT, MT_DATA);
|
|
if (dmp == NULL)
|
|
return DECOMP_ERROR;
|
|
mret = dmp;
|
|
dmp->m_len = 0;
|
|
dmp->m_next = NULL;
|
|
MCLGET(dmp, M_DONTWAIT);
|
|
dmp->m_data += db->hdrlen;
|
|
wptr = mtod(dmp, u_char *);
|
|
space = M_TRAILINGSPACE(dmp) - PPP_HDRLEN + 1;
|
|
|
|
/*
|
|
* Fill in the ppp header, but not the last byte of the protocol
|
|
* (that comes from the decompressed data).
|
|
*/
|
|
wptr[0] = adrs;
|
|
wptr[1] = ctrl;
|
|
wptr[2] = 0;
|
|
wptr += PPP_HDRLEN - 1;
|
|
|
|
ilen = len;
|
|
oldcode = CLEAR;
|
|
explen = 0;
|
|
for (;;) {
|
|
if (len == 0) {
|
|
cmp = cmp->m_next;
|
|
if (!cmp) /* quit at end of message */
|
|
break;
|
|
rptr = mtod(cmp, u_char *);
|
|
len = cmp->m_len;
|
|
ilen += len;
|
|
continue; /* handle 0-length buffers */
|
|
}
|
|
|
|
/*
|
|
* Accumulate bytes until we have a complete code.
|
|
* Then get the next code, relying on the 32-bit,
|
|
* unsigned accm to mask the result.
|
|
*/
|
|
bitno -= 8;
|
|
accm |= *rptr++ << bitno;
|
|
--len;
|
|
if (tgtbitno < bitno)
|
|
continue;
|
|
incode = accm >> tgtbitno;
|
|
accm <<= n_bits;
|
|
bitno += n_bits;
|
|
|
|
if (incode == CLEAR) {
|
|
/*
|
|
* The dictionary must only be cleared at
|
|
* the end of a packet. But there could be an
|
|
* empty mbuf at the end.
|
|
*/
|
|
if (len > 0 || cmp->m_next != NULL) {
|
|
while ((cmp = cmp->m_next) != NULL)
|
|
len += cmp->m_len;
|
|
if (len > 0) {
|
|
m_freem(mret);
|
|
if (db->debug)
|
|
printf("bsd_decomp%d: bad CLEAR\n", db->unit);
|
|
return DECOMP_FATALERROR; /* probably a bug */
|
|
}
|
|
}
|
|
bsd_clear(db);
|
|
explen = ilen = 0;
|
|
break;
|
|
}
|
|
|
|
if (incode > max_ent + 2 || incode > db->maxmaxcode
|
|
|| (incode > max_ent && oldcode == CLEAR)) {
|
|
m_freem(mret);
|
|
if (db->debug) {
|
|
printf("bsd_decomp%d: bad code 0x%x oldcode=0x%x ",
|
|
db->unit, incode, oldcode);
|
|
printf("max_ent=0x%x explen=%d seqno=%d\n",
|
|
max_ent, explen, db->seqno);
|
|
}
|
|
return DECOMP_FATALERROR; /* probably a bug */
|
|
}
|
|
|
|
/* Special case for KwKwK string. */
|
|
if (incode > max_ent) {
|
|
finchar = oldcode;
|
|
extra = 1;
|
|
} else {
|
|
finchar = incode;
|
|
extra = 0;
|
|
}
|
|
|
|
codelen = db->lens[finchar];
|
|
explen += codelen + extra;
|
|
if (explen > db->mru + 1) {
|
|
m_freem(mret);
|
|
if (db->debug) {
|
|
printf("bsd_decomp%d: ran out of mru\n", db->unit);
|
|
#ifdef DEBUG
|
|
while ((cmp = cmp->m_next) != NULL)
|
|
len += cmp->m_len;
|
|
printf(" len=%d, finchar=0x%x, codelen=%d, explen=%d\n",
|
|
len, finchar, codelen, explen);
|
|
#endif
|
|
}
|
|
return DECOMP_FATALERROR;
|
|
}
|
|
|
|
/*
|
|
* For simplicity, the decoded characters go in a single mbuf,
|
|
* so we allocate a single extra cluster mbuf if necessary.
|
|
*/
|
|
if ((space -= codelen + extra) < 0) {
|
|
dmp->m_len = wptr - mtod(dmp, u_char *);
|
|
MGET(m, M_DONTWAIT, MT_DATA);
|
|
if (m == NULL) {
|
|
m_freem(mret);
|
|
return DECOMP_ERROR;
|
|
}
|
|
m->m_len = 0;
|
|
m->m_next = NULL;
|
|
dmp->m_next = m;
|
|
MCLGET(m, M_DONTWAIT);
|
|
space = M_TRAILINGSPACE(m) - (codelen + extra);
|
|
if (space < 0) {
|
|
/* now that's what I call *compression*. */
|
|
m_freem(mret);
|
|
return DECOMP_ERROR;
|
|
}
|
|
dmp = m;
|
|
wptr = mtod(dmp, u_char *);
|
|
}
|
|
|
|
/*
|
|
* Decode this code and install it in the decompressed buffer.
|
|
*/
|
|
p = (wptr += codelen);
|
|
while (finchar > LAST) {
|
|
dictp = &db->dict[db->dict[finchar].cptr];
|
|
#ifdef DEBUG
|
|
if (--codelen <= 0 || dictp->codem1 != finchar-1)
|
|
goto bad;
|
|
#endif
|
|
*--p = dictp->f.hs.suffix;
|
|
finchar = dictp->f.hs.prefix;
|
|
}
|
|
*--p = finchar;
|
|
|
|
#ifdef DEBUG
|
|
if (--codelen != 0)
|
|
printf("bsd_decomp%d: short by %d after code 0x%x, max_ent=0x%x\n",
|
|
db->unit, codelen, incode, max_ent);
|
|
#endif
|
|
|
|
if (extra) /* the KwKwK case again */
|
|
*wptr++ = finchar;
|
|
|
|
/*
|
|
* If not first code in a packet, and
|
|
* if not out of code space, then allocate a new code.
|
|
*
|
|
* Keep the hash table correct so it can be used
|
|
* with uncompressed packets.
|
|
*/
|
|
if (oldcode != CLEAR && max_ent < db->maxmaxcode) {
|
|
struct bsd_dict *dictp2;
|
|
u_int32_t fcode;
|
|
u_int32_t hval, disp;
|
|
|
|
fcode = BSD_KEY(oldcode,finchar);
|
|
hval = BSD_HASH(oldcode,finchar,db->hshift);
|
|
dictp = &db->dict[hval];
|
|
|
|
/* look for a free hash table entry */
|
|
if (dictp->codem1 < max_ent) {
|
|
disp = (hval == 0) ? 1 : hval;
|
|
do {
|
|
hval += disp;
|
|
if (hval >= db->hsize)
|
|
hval -= db->hsize;
|
|
dictp = &db->dict[hval];
|
|
} while (dictp->codem1 < max_ent);
|
|
}
|
|
|
|
/*
|
|
* Invalidate previous hash table entry
|
|
* assigned this code, and then take it over
|
|
*/
|
|
dictp2 = &db->dict[max_ent+1];
|
|
if (db->dict[dictp2->cptr].codem1 == max_ent) {
|
|
db->dict[dictp2->cptr].codem1 = BADCODEM1;
|
|
}
|
|
dictp2->cptr = hval;
|
|
dictp->codem1 = max_ent;
|
|
dictp->f.fcode = fcode;
|
|
|
|
db->max_ent = ++max_ent;
|
|
db->lens[max_ent] = db->lens[oldcode]+1;
|
|
|
|
/* Expand code size if needed. */
|
|
if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) {
|
|
db->n_bits = ++n_bits;
|
|
tgtbitno = 32-n_bits;
|
|
}
|
|
}
|
|
oldcode = incode;
|
|
}
|
|
dmp->m_len = wptr - mtod(dmp, u_char *);
|
|
|
|
/*
|
|
* Keep the checkpoint right so that incompressible packets
|
|
* clear the dictionary at the right times.
|
|
*/
|
|
db->bytes_out += ilen;
|
|
db->in_count += explen;
|
|
if (bsd_check(db) && db->debug) {
|
|
printf("bsd_decomp%d: peer should have cleared dictionary\n",
|
|
db->unit);
|
|
}
|
|
|
|
++db->comp_count;
|
|
db->comp_bytes += ilen + BSD_OVHD;
|
|
++db->uncomp_count;
|
|
db->uncomp_bytes += explen;
|
|
|
|
*dmpp = mret;
|
|
return DECOMP_OK;
|
|
|
|
#ifdef DEBUG
|
|
bad:
|
|
if (codelen <= 0) {
|
|
printf("bsd_decomp%d: fell off end of chain ", db->unit);
|
|
printf("0x%x at 0x%x by 0x%x, max_ent=0x%x\n",
|
|
incode, finchar, db->dict[finchar].cptr, max_ent);
|
|
} else if (dictp->codem1 != finchar-1) {
|
|
printf("bsd_decomp%d: bad code chain 0x%x finchar=0x%x ",
|
|
db->unit, incode, finchar);
|
|
printf("oldcode=0x%x cptr=0x%x codem1=0x%x\n", oldcode,
|
|
db->dict[finchar].cptr, dictp->codem1);
|
|
}
|
|
m_freem(mret);
|
|
return DECOMP_FATALERROR;
|
|
#endif /* DEBUG */
|
|
}
|