aed5570872
begun with a repo-copy of mac.h to mac_framework.h. sys/mac.h now contains the userspace and user<->kernel API and definitions, with all in-kernel interfaces moved to mac_framework.h, which is now included across most of the kernel instead. This change is the first step in a larger cleanup and sweep of MAC Framework interfaces in the kernel, and will not be MFC'd. Obtained from: TrustedBSD Project Sponsored by: SPARTA
1118 lines
29 KiB
C
1118 lines
29 KiB
C
/*-
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* Because this code is derived from the 4.3BSD compress source:
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*
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*
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* Copyright (c) 1985, 1986 The Regents of the University of California.
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* All rights reserved.
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*
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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
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* and Joseph Orost.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* 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
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* 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
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* 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 "opt_mac.h"
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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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#include <security/mac/mac_framework.h>
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/*
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* PPP "BSD compress" compression
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* The differences between this compression and the classic BSD LZW
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* source are obvious from the requirement that the classic code worked
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* with files while this handles arbitrarily long streams that
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* are broken into packets. They are:
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*
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* When the code size expands, a block of junk is not emitted by
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* the compressor and not expected by the decompressor.
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*
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* 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
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* end forces a code to be emitted, but does not imply that a
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* new sequence has been seen.
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*
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* The compression ratio is checked at the first end of a packet
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* after the appropriate gap. Besides simplifying and speeding
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* 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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/*
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* A dictionary for doing BSD compress.
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*/
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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 */
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u_int bytes_out; /* compressed bytes, aged */
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u_int ratio; /* recent compression ratio */
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u_int checkpoint; /* when to next check the ratio */
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u_int clear_count; /* times dictionary cleared */
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u_int incomp_count; /* incompressible packets */
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u_int incomp_bytes; /* incompressible bytes */
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u_int uncomp_count; /* uncompressed packets */
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u_int uncomp_bytes; /* uncompressed bytes */
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u_int comp_count; /* compressed packets */
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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 {
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union { /* hash value */
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u_int32_t fcode;
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struct {
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#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 */
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u_char pad;
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#else
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u_char pad;
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u_char suffix; /* last character of new code */
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u_int16_t prefix; /* preceding code */
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#endif
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} hs;
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} f;
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u_int16_t codem1; /* output of hash table -1 */
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u_int16_t cptr; /* map code to hash table entry */
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} dict[1];
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};
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#define BSD_OVHD 2 /* BSD compress overhead/packet */
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#define BSD_INIT_BITS BSD_MIN_BITS
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static void bsd_clear(struct bsd_db *db);
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static int bsd_check(struct bsd_db *db);
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static void *bsd_alloc(u_char *options, int opt_len, int decomp);
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static int bsd_init(struct bsd_db *db, u_char *options, int opt_len,
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int unit, int hdrlen, int mru, int debug, int decomp);
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static void *bsd_comp_alloc(u_char *options, int opt_len);
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static void *bsd_decomp_alloc(u_char *options, int opt_len);
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static void bsd_free(void *state);
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static int bsd_comp_init(void *state, u_char *options, int opt_len,
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int unit, int hdrlen, int debug);
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static int bsd_decomp_init(void *state, u_char *options, int opt_len,
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int unit, int hdrlen, int mru, int debug);
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static int bsd_compress(void *state, struct mbuf **mret, struct mbuf *mp,
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int slen, int maxolen);
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static void bsd_incomp(void *state, struct mbuf *dmsg);
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static int bsd_decompress(void *state, struct mbuf *cmp,
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struct mbuf **dmpp);
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static void bsd_reset(void *state);
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static void bsd_comp_stats(void *state, struct compstat *stats);
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/*
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* Procedures exported to if_ppp.c.
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*/
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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 */
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bsd_comp_init, /* comp_init */
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bsd_reset, /* comp_reset */
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bsd_compress, /* compress */
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bsd_comp_stats, /* comp_stat */
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bsd_decomp_alloc, /* decomp_alloc */
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bsd_free, /* decomp_free */
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bsd_decomp_init, /* decomp_init */
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bsd_reset, /* decomp_reset */
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bsd_decompress, /* decompress */
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bsd_incomp, /* incomp */
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bsd_comp_stats, /* decomp_stat */
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};
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/*
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* the next two codes should not be changed lightly, as they must not
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* lie within the contiguous general code space.
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*/
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#define CLEAR 256 /* table clear output code */
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#define FIRST 257 /* first free entry */
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#define LAST 255
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#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)) \
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^ (u_int32_t)(prefix))
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#define BSD_KEY(prefix,suffix) ((((u_int32_t)(suffix)) << 16) \
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+ (u_int32_t)(prefix))
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#define CHECK_GAP 10000 /* Ratio check interval */
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#define RATIO_SCALE_LOG 8
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#define RATIO_SCALE (1<<RATIO_SCALE_LOG)
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#define RATIO_MAX (0x7fffffff>>RATIO_SCALE_LOG)
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/*
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* clear the dictionary
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*/
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static void
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bsd_clear(db)
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struct bsd_db *db;
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{
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db->clear_count++;
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db->max_ent = FIRST-1;
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db->n_bits = BSD_INIT_BITS;
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db->ratio = 0;
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db->bytes_out = 0;
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db->in_count = 0;
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db->checkpoint = CHECK_GAP;
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}
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/*
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* If the dictionary is full, then see if it is time to reset it.
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*
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* Compute the compression ratio using fixed-point arithmetic
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* with 8 fractional bits.
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*
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* Since we have an infinite stream instead of a single file,
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* watch only the local compression ratio.
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*
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* Since both peers must reset the dictionary at the same time even in
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* the absence of CLEAR codes (while packets are incompressible), they
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* must compute the same ratio.
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*/
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static int /* 1=output CLEAR */
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bsd_check(db)
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struct bsd_db *db;
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{
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u_int new_ratio;
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if (db->in_count >= db->checkpoint) {
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/* age the ratio by limiting the size of the counts */
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if (db->in_count >= RATIO_MAX
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|| db->bytes_out >= RATIO_MAX) {
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db->in_count -= db->in_count/4;
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db->bytes_out -= db->bytes_out/4;
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}
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db->checkpoint = db->in_count + CHECK_GAP;
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if (db->max_ent >= db->maxmaxcode) {
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/* Reset the dictionary only if the ratio is worse,
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* or if it looks as if it has been poisoned
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* by incompressible data.
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*
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* This does not overflow, because
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* db->in_count <= RATIO_MAX.
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*/
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new_ratio = db->in_count << RATIO_SCALE_LOG;
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if (db->bytes_out != 0)
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new_ratio /= db->bytes_out;
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if (new_ratio < db->ratio || new_ratio < 1 * RATIO_SCALE) {
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bsd_clear(db);
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return 1;
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}
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db->ratio = new_ratio;
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}
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}
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return 0;
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}
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/*
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* Return statistics.
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*/
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static void
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bsd_comp_stats(state, stats)
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void *state;
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struct compstat *stats;
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{
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struct bsd_db *db = (struct bsd_db *) state;
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u_int out;
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stats->unc_bytes = db->uncomp_bytes;
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stats->unc_packets = db->uncomp_count;
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stats->comp_bytes = db->comp_bytes;
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stats->comp_packets = db->comp_count;
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stats->inc_bytes = db->incomp_bytes;
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stats->inc_packets = db->incomp_count;
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stats->ratio = db->in_count;
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out = db->bytes_out;
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if (stats->ratio <= 0x7fffff)
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stats->ratio <<= 8;
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else
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out >>= 8;
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if (out != 0)
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stats->ratio /= out;
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}
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/*
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* Reset state, as on a CCP ResetReq.
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*/
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static void
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bsd_reset(state)
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void *state;
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{
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struct bsd_db *db = (struct bsd_db *) state;
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db->seqno = 0;
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bsd_clear(db);
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db->clear_count = 0;
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}
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/*
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* Allocate space for a (de) compressor.
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*/
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static void *
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bsd_alloc(options, opt_len, decomp)
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u_char *options;
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int opt_len, decomp;
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{
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int bits;
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u_int newlen, hsize, hshift, maxmaxcode;
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struct bsd_db *db;
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if (opt_len < CILEN_BSD_COMPRESS || options[0] != CI_BSD_COMPRESS
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|| options[1] != CILEN_BSD_COMPRESS
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|| BSD_VERSION(options[2]) != BSD_CURRENT_VERSION)
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return NULL;
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bits = BSD_NBITS(options[2]);
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switch (bits) {
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case 9: /* needs 82152 for both directions */
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case 10: /* needs 84144 */
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case 11: /* needs 88240 */
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case 12: /* needs 96432 */
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hsize = 5003;
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hshift = 4;
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break;
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case 13: /* needs 176784 */
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hsize = 9001;
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hshift = 5;
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break;
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case 14: /* needs 353744 */
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hsize = 18013;
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hshift = 6;
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break;
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case 15: /* needs 691440 */
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hsize = 35023;
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hshift = 7;
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break;
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case 16: /* needs 1366160--far too much, */
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/* hsize = 69001; */ /* and 69001 is too big for cptr */
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/* hshift = 8; */ /* in struct bsd_db */
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/* break; */
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default:
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return NULL;
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}
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maxmaxcode = MAXCODE(bits);
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newlen = sizeof(*db) + (hsize-1) * (sizeof(db->dict[0]));
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MALLOC(db, struct bsd_db *, newlen, M_DEVBUF, M_NOWAIT);
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if (!db)
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return NULL;
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bzero(db, sizeof(*db) - sizeof(db->dict));
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if (!decomp) {
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db->lens = NULL;
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} else {
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MALLOC(db->lens, u_int16_t *, (maxmaxcode+1) * sizeof(db->lens[0]),
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M_DEVBUF, M_NOWAIT);
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if (!db->lens) {
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free(db, M_DEVBUF);
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return NULL;
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}
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}
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db->totlen = newlen;
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db->hsize = hsize;
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db->hshift = hshift;
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db->maxmaxcode = maxmaxcode;
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db->maxbits = bits;
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return (void *) db;
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}
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static void
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bsd_free(state)
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void *state;
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{
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struct bsd_db *db = (struct bsd_db *) state;
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if (db->lens)
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free(db->lens, M_DEVBUF);
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free(db, M_DEVBUF);
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}
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static void *
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bsd_comp_alloc(options, opt_len)
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u_char *options;
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int opt_len;
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{
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return bsd_alloc(options, opt_len, 0);
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}
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static void *
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bsd_decomp_alloc(options, opt_len)
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u_char *options;
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int opt_len;
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{
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return bsd_alloc(options, opt_len, 1);
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}
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/*
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* Initialize the database.
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*/
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static int
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bsd_init(db, options, opt_len, unit, hdrlen, mru, debug, decomp)
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struct bsd_db *db;
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u_char *options;
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int opt_len, unit, hdrlen, mru, debug, decomp;
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{
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int i;
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if (opt_len < CILEN_BSD_COMPRESS || options[0] != CI_BSD_COMPRESS
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|| options[1] != CILEN_BSD_COMPRESS
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|| BSD_VERSION(options[2]) != BSD_CURRENT_VERSION
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|| BSD_NBITS(options[2]) != db->maxbits
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|| (decomp && db->lens == NULL))
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return 0;
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if (decomp) {
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i = LAST+1;
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while (i != 0)
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db->lens[--i] = 1;
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}
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i = db->hsize;
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while (i != 0) {
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db->dict[--i].codem1 = BADCODEM1;
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db->dict[i].cptr = 0;
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}
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db->unit = unit;
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db->hdrlen = hdrlen;
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db->mru = mru;
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#ifndef DEBUG
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if (debug)
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#endif
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db->debug = 1;
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bsd_reset(db);
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return 1;
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}
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static int
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bsd_comp_init(state, options, opt_len, unit, hdrlen, debug)
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void *state;
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u_char *options;
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int opt_len, unit, hdrlen, debug;
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{
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return bsd_init((struct bsd_db *) state, options, opt_len,
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unit, hdrlen, 0, debug, 0);
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}
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static int
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bsd_decomp_init(state, options, opt_len, unit, hdrlen, mru, debug)
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void *state;
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u_char *options;
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int opt_len, unit, hdrlen, mru, debug;
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{
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return bsd_init((struct bsd_db *) state, options, opt_len,
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unit, hdrlen, mru, debug, 1);
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}
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|
|
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/*
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* compress a packet
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* One change from the BSD compress command is that when the
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* code size expands, we do not output a bunch of padding.
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*/
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static int /* new slen */
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bsd_compress(state, mret, mp, slen, maxolen)
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void *state;
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struct mbuf **mret; /* return compressed mbuf chain here */
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struct mbuf *mp; /* from here */
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int slen; /* uncompressed length */
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int maxolen; /* max compressed length */
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{
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struct bsd_db *db = (struct bsd_db *) state;
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int hshift = db->hshift;
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u_int max_ent = db->max_ent;
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u_int n_bits = db->n_bits;
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u_int bitno = 32;
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u_int32_t accm = 0, fcode;
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struct bsd_dict *dictp;
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u_char c;
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int hval, disp, ent, ilen;
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u_char *rptr, *wptr;
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u_char *cp_end;
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int olen;
|
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struct mbuf *m;
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|
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#define PUTBYTE(v) { \
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++olen; \
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if (wptr) { \
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*wptr++ = (v); \
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if (wptr >= cp_end) { \
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m->m_len = wptr - mtod(m, u_char *); \
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MGET(m->m_next, M_DONTWAIT, MT_DATA); \
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m = m->m_next; \
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if (m) { \
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m->m_len = 0; \
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if (maxolen - olen > MLEN) \
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MCLGET(m, M_DONTWAIT); \
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wptr = mtod(m, u_char *); \
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cp_end = wptr + M_TRAILINGSPACE(m); \
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} else \
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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.
|
|
*/
|
|
static 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;
|
|
#ifdef MAC
|
|
mac_copy_mbuf(cmp, dmp);
|
|
#endif
|
|
|
|
/*
|
|
* 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 */
|
|
}
|