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7c8347a91d
vmalloc() returns a void pointer - no need to cast the return value. Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
930 lines
23 KiB
C
930 lines
23 KiB
C
/*
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* BSD compression module
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*
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* Patched version for ISDN syncPPP written 1997/1998 by Michael Hipp
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* The whole module is now SKB based.
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*
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*/
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/*
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* Update: The Berkeley copyright was changed, and the change
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* is retroactive to all "true" BSD software (ie everything
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* from UCB as opposed to other peoples code that just carried
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* the same license). The new copyright doesn't clash with the
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* GPL, so the module-only restriction has been removed..
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*/
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/*
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* Original copyright notice:
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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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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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/fcntl.h>
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#include <linux/interrupt.h>
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#include <linux/ptrace.h>
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#include <linux/ioport.h>
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#include <linux/in.h>
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#include <linux/slab.h>
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#include <linux/tty.h>
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#include <linux/errno.h>
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#include <linux/string.h> /* used in new tty drivers */
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#include <linux/signal.h> /* used in new tty drivers */
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#include <linux/bitops.h>
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#include <asm/system.h>
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#include <asm/byteorder.h>
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#include <asm/types.h>
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#include <linux/if.h>
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#include <linux/if_ether.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/inet.h>
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#include <linux/ioctl.h>
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#include <linux/vmalloc.h>
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#include <linux/ppp_defs.h>
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#include <linux/isdn.h>
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#include <linux/isdn_ppp.h>
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#include <linux/ip.h>
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#include <linux/tcp.h>
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#include <linux/if_arp.h>
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#include <linux/ppp-comp.h>
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#include "isdn_ppp.h"
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MODULE_DESCRIPTION("ISDN4Linux: BSD Compression for PPP over ISDN");
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MODULE_LICENSE("Dual BSD/GPL");
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#define BSD_VERSION(x) ((x) >> 5)
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#define BSD_NBITS(x) ((x) & 0x1F)
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#define BSD_CURRENT_VERSION 1
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#define DEBUG 1
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/*
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* A dictionary for doing BSD compress.
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*/
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struct bsd_dict {
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u32 fcode;
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u16 codem1; /* output of hash table -1 */
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u16 cptr; /* map code to hash table entry */
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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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unsigned int hsize; /* size of the hash table */
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unsigned char hshift; /* used in hash function */
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unsigned char n_bits; /* current bits/code */
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unsigned char maxbits; /* maximum bits/code */
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unsigned char debug; /* non-zero if debug desired */
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unsigned char unit; /* ppp unit number */
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u16 seqno; /* sequence # of next packet */
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unsigned int mru; /* size of receive (decompress) bufr */
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unsigned int maxmaxcode; /* largest valid code */
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unsigned int max_ent; /* largest code in use */
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unsigned int in_count; /* uncompressed bytes, aged */
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unsigned int bytes_out; /* compressed bytes, aged */
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unsigned int ratio; /* recent compression ratio */
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unsigned int checkpoint; /* when to next check the ratio */
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unsigned int clear_count; /* times dictionary cleared */
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unsigned int incomp_count; /* incompressible packets */
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unsigned int incomp_bytes; /* incompressible bytes */
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unsigned int uncomp_count; /* uncompressed packets */
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unsigned int uncomp_bytes; /* uncompressed bytes */
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unsigned int comp_count; /* compressed packets */
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unsigned int comp_bytes; /* compressed bytes */
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unsigned short *lens; /* array of lengths of codes */
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struct bsd_dict *dict; /* dictionary */
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int xmit;
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};
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#define BSD_OVHD 2 /* BSD compress overhead/packet */
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#define MIN_BSD_BITS 9
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#define BSD_INIT_BITS MIN_BSD_BITS
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#define MAX_BSD_BITS 15
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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(MAX_BSD_BITS);
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#define BSD_HASH(prefix,suffix,hshift) ((((unsigned long)(suffix))<<(hshift)) \
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^ (unsigned long)(prefix))
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#define BSD_KEY(prefix,suffix) ((((unsigned long)(suffix)) << 16) \
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+ (unsigned long)(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 bsd_clear(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->bytes_out = 0;
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db->in_count = 0;
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db->incomp_count = 0;
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db->ratio = 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 bsd_check (struct bsd_db *db) /* 1=output CLEAR */
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{
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unsigned int new_ratio;
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if (db->in_count >= db->checkpoint)
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{
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/* age the ratio by limiting the size of the counts */
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if (db->in_count >= RATIO_MAX || db->bytes_out >= RATIO_MAX)
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{
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db->in_count -= (db->in_count >> 2);
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db->bytes_out -= (db->bytes_out >> 2);
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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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{
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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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{
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new_ratio /= db->bytes_out;
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}
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if (new_ratio < db->ratio || new_ratio < 1 * RATIO_SCALE)
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{
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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 bsd_stats (void *state, struct compstat *stats)
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{
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struct bsd_db *db = (struct bsd_db *) state;
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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->in_count = db->in_count;
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stats->bytes_out = db->bytes_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 bsd_reset (void *state,unsigned char code, unsigned char id,
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unsigned char *data, unsigned len,
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struct isdn_ppp_resetparams *rsparm)
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{
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struct bsd_db *db = (struct bsd_db *) state;
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bsd_clear(db);
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db->seqno = 0;
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db->clear_count = 0;
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}
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/*
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* Release the compression structure
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*/
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static void bsd_free (void *state)
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{
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struct bsd_db *db = (struct bsd_db *) state;
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if (db) {
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/*
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* Release the dictionary
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*/
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vfree(db->dict);
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db->dict = NULL;
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/*
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* Release the string buffer
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*/
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vfree(db->lens);
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db->lens = NULL;
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/*
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* Finally release the structure itself.
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*/
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kfree(db);
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}
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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 *bsd_alloc (struct isdn_ppp_comp_data *data)
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{
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int bits;
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unsigned int hsize, hshift, maxmaxcode;
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struct bsd_db *db;
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int decomp;
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static unsigned int htab[][2] = {
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{ 5003 , 4 } , { 5003 , 4 } , { 5003 , 4 } , { 5003 , 4 } ,
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{ 9001 , 5 } , { 18013 , 6 } , { 35023 , 7 } , { 69001 , 8 }
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};
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if (data->optlen != 1 || data->num != CI_BSD_COMPRESS
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|| BSD_VERSION(data->options[0]) != BSD_CURRENT_VERSION)
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return NULL;
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bits = BSD_NBITS(data->options[0]);
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if(bits < 9 || bits > 15)
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return NULL;
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hsize = htab[bits-9][0];
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hshift = htab[bits-9][1];
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/*
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* Allocate the main control structure for this instance.
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*/
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maxmaxcode = MAXCODE(bits);
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db = kzalloc (sizeof (struct bsd_db),GFP_KERNEL);
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if (!db)
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return NULL;
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db->xmit = data->flags & IPPP_COMP_FLAG_XMIT;
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decomp = db->xmit ? 0 : 1;
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/*
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* Allocate space for the dictionary. This may be more than one page in
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* length.
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*/
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db->dict = vmalloc(hsize * sizeof(struct bsd_dict));
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if (!db->dict) {
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bsd_free (db);
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return NULL;
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}
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/*
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* If this is the compression buffer then there is no length data.
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* For decompression, the length information is needed as well.
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*/
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if (!decomp)
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db->lens = NULL;
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else {
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db->lens = vmalloc((maxmaxcode + 1) * sizeof(db->lens[0]));
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if (!db->lens) {
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bsd_free (db);
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return (NULL);
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}
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}
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/*
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* Initialize the data information for the compression code
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*/
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db->totlen = sizeof (struct bsd_db) + (sizeof (struct bsd_dict) * hsize);
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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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/*
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* Initialize the database.
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*/
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static int bsd_init (void *state, struct isdn_ppp_comp_data *data, int unit, int debug)
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{
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struct bsd_db *db = state;
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int indx;
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int decomp;
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if(!state || !data) {
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printk(KERN_ERR "isdn_bsd_init: [%d] ERR, state %lx data %lx\n",unit,(long)state,(long)data);
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return 0;
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}
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decomp = db->xmit ? 0 : 1;
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if (data->optlen != 1 || data->num != CI_BSD_COMPRESS
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|| (BSD_VERSION(data->options[0]) != BSD_CURRENT_VERSION)
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|| (BSD_NBITS(data->options[0]) != db->maxbits)
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|| (decomp && db->lens == NULL)) {
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printk(KERN_ERR "isdn_bsd: %d %d %d %d %lx\n",data->optlen,data->num,data->options[0],decomp,(unsigned long)db->lens);
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return 0;
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}
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if (decomp)
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for(indx=LAST;indx>=0;indx--)
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db->lens[indx] = 1;
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indx = db->hsize;
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while (indx-- != 0) {
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db->dict[indx].codem1 = BADCODEM1;
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db->dict[indx].cptr = 0;
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}
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db->unit = unit;
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db->mru = 0;
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db->debug = 1;
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bsd_reset(db,0,0,NULL,0,NULL);
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return 1;
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}
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/*
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* Obtain pointers to the various structures in the compression tables
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*/
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#define dict_ptrx(p,idx) &(p->dict[idx])
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#define lens_ptrx(p,idx) &(p->lens[idx])
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#ifdef DEBUG
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static unsigned short *lens_ptr(struct bsd_db *db, int idx)
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{
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if ((unsigned int) idx > (unsigned int) db->maxmaxcode) {
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printk (KERN_DEBUG "<9>ppp: lens_ptr(%d) > max\n", idx);
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idx = 0;
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}
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return lens_ptrx (db, idx);
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}
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static struct bsd_dict *dict_ptr(struct bsd_db *db, int idx)
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{
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if ((unsigned int) idx >= (unsigned int) db->hsize) {
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printk (KERN_DEBUG "<9>ppp: dict_ptr(%d) > max\n", idx);
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idx = 0;
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}
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return dict_ptrx (db, idx);
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}
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#else
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#define lens_ptr(db,idx) lens_ptrx(db,idx)
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#define dict_ptr(db,idx) dict_ptrx(db,idx)
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#endif
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/*
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* compress a packet
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*/
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static int bsd_compress (void *state, struct sk_buff *skb_in, struct sk_buff *skb_out,int proto)
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{
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struct bsd_db *db;
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int hshift;
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unsigned int max_ent;
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unsigned int n_bits;
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unsigned int bitno;
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unsigned long accm;
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int ent;
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unsigned long fcode;
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struct bsd_dict *dictp;
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unsigned char c;
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int hval,disp,ilen,mxcode;
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unsigned char *rptr = skb_in->data;
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int isize = skb_in->len;
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#define OUTPUT(ent) \
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{ \
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bitno -= n_bits; \
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accm |= ((ent) << bitno); \
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do { \
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if(skb_out && skb_tailroom(skb_out) > 0) \
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*(skb_put(skb_out,1)) = (unsigned char) (accm>>24); \
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accm <<= 8; \
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bitno += 8; \
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} while (bitno <= 24); \
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}
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/*
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* If the protocol is not in the range we're interested in,
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* just return without compressing the packet. If it is,
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* the protocol becomes the first byte to compress.
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*/
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printk(KERN_DEBUG "bsd_compress called with %x\n",proto);
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ent = proto;
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if (proto < 0x21 || proto > 0xf9 || !(proto & 0x1) )
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return 0;
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db = (struct bsd_db *) state;
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hshift = db->hshift;
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max_ent = db->max_ent;
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n_bits = db->n_bits;
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bitno = 32;
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accm = 0;
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mxcode = MAXCODE (n_bits);
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/* This is the PPP header information */
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if(skb_out && skb_tailroom(skb_out) >= 2) {
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char *v = skb_put(skb_out,2);
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/* we only push our own data on the header,
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AC,PC and protos is pushed by caller */
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v[0] = db->seqno >> 8;
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v[1] = db->seqno;
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}
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ilen = ++isize; /* This is off by one, but that is what is in draft! */
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while (--ilen > 0) {
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c = *rptr++;
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fcode = BSD_KEY (ent, c);
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hval = BSD_HASH (ent, c, hshift);
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dictp = dict_ptr (db, hval);
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/* Validate and then check the entry. */
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if (dictp->codem1 >= max_ent)
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goto nomatch;
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if (dictp->fcode == fcode) {
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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 = dict_ptr (db, hval);
|
|
if (dictp->codem1 >= max_ent)
|
|
goto nomatch;
|
|
} while (dictp->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;
|
|
struct bsd_dict *dictp3;
|
|
int indx;
|
|
|
|
/* expand code size if needed */
|
|
if (max_ent >= mxcode) {
|
|
db->n_bits = ++n_bits;
|
|
mxcode = MAXCODE (n_bits);
|
|
}
|
|
|
|
/*
|
|
* Invalidate old hash table entry using
|
|
* this code, and then take it over.
|
|
*/
|
|
dictp2 = dict_ptr (db, max_ent + 1);
|
|
indx = dictp2->cptr;
|
|
dictp3 = dict_ptr (db, indx);
|
|
|
|
if (dictp3->codem1 == max_ent)
|
|
dictp3->codem1 = BADCODEM1;
|
|
|
|
dictp2->cptr = hval;
|
|
dictp->codem1 = max_ent;
|
|
dictp->fcode = fcode;
|
|
db->max_ent = ++max_ent;
|
|
|
|
if (db->lens) {
|
|
unsigned short *len1 = lens_ptr (db, max_ent);
|
|
unsigned short *len2 = lens_ptr (db, ent);
|
|
*len1 = *len2 + 1;
|
|
}
|
|
}
|
|
ent = c;
|
|
}
|
|
|
|
OUTPUT(ent); /* output the last code */
|
|
|
|
if(skb_out)
|
|
db->bytes_out += skb_out->len; /* Do not count bytes from here */
|
|
db->uncomp_bytes += isize;
|
|
db->in_count += isize;
|
|
++db->uncomp_count;
|
|
++db->seqno;
|
|
|
|
if (bitno < 32)
|
|
++db->bytes_out; /* must be set before calling bsd_check */
|
|
|
|
/*
|
|
* Generate the clear command if needed
|
|
*/
|
|
|
|
if (bsd_check(db))
|
|
OUTPUT (CLEAR);
|
|
|
|
/*
|
|
* Pad dribble bits of last code with ones.
|
|
* Do not emit a completely useless byte of ones.
|
|
*/
|
|
if (bitno < 32 && skb_out && skb_tailroom(skb_out) > 0)
|
|
*(skb_put(skb_out,1)) = (unsigned char) ((accm | (0xff << (bitno-8))) >> 24);
|
|
|
|
/*
|
|
* Increase code size if we would have without the packet
|
|
* boundary because the decompressor will do so.
|
|
*/
|
|
if (max_ent >= mxcode && max_ent < db->maxmaxcode)
|
|
db->n_bits++;
|
|
|
|
/* If output length is too large then this is an incompressible frame. */
|
|
if (!skb_out || (skb_out && skb_out->len >= skb_in->len) ) {
|
|
++db->incomp_count;
|
|
db->incomp_bytes += isize;
|
|
return 0;
|
|
}
|
|
|
|
/* Count the number of compressed frames */
|
|
++db->comp_count;
|
|
db->comp_bytes += skb_out->len;
|
|
return skb_out->len;
|
|
|
|
#undef OUTPUT
|
|
}
|
|
|
|
/*
|
|
* Update the "BSD Compress" dictionary on the receiver for
|
|
* incompressible data by pretending to compress the incoming data.
|
|
*/
|
|
static void bsd_incomp (void *state, struct sk_buff *skb_in,int proto)
|
|
{
|
|
bsd_compress (state, skb_in, NULL, proto);
|
|
}
|
|
|
|
/*
|
|
* Decompress "BSD Compress".
|
|
*/
|
|
static int bsd_decompress (void *state, struct sk_buff *skb_in, struct sk_buff *skb_out,
|
|
struct isdn_ppp_resetparams *rsparm)
|
|
{
|
|
struct bsd_db *db;
|
|
unsigned int max_ent;
|
|
unsigned long accm;
|
|
unsigned int bitno; /* 1st valid bit in accm */
|
|
unsigned int n_bits;
|
|
unsigned int tgtbitno; /* bitno when we have a code */
|
|
struct bsd_dict *dictp;
|
|
int seq;
|
|
unsigned int incode;
|
|
unsigned int oldcode;
|
|
unsigned int finchar;
|
|
unsigned char *p,*ibuf;
|
|
int ilen;
|
|
int codelen;
|
|
int extra;
|
|
|
|
db = (struct bsd_db *) state;
|
|
max_ent = db->max_ent;
|
|
accm = 0;
|
|
bitno = 32; /* 1st valid bit in accm */
|
|
n_bits = db->n_bits;
|
|
tgtbitno = 32 - n_bits; /* bitno when we have a code */
|
|
|
|
printk(KERN_DEBUG "bsd_decompress called\n");
|
|
|
|
if(!skb_in || !skb_out) {
|
|
printk(KERN_ERR "bsd_decompress called with NULL parameter\n");
|
|
return DECOMP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* Get the sequence number.
|
|
*/
|
|
if( (p = skb_pull(skb_in,2)) == NULL) {
|
|
return DECOMP_ERROR;
|
|
}
|
|
p-=2;
|
|
seq = (p[0] << 8) + p[1];
|
|
ilen = skb_in->len;
|
|
ibuf = skb_in->data;
|
|
|
|
/*
|
|
* Check the sequence number and give up if it differs from
|
|
* the value we're expecting.
|
|
*/
|
|
if (seq != db->seqno) {
|
|
if (db->debug) {
|
|
printk(KERN_DEBUG "bsd_decomp%d: bad sequence # %d, expected %d\n",
|
|
db->unit, seq, db->seqno - 1);
|
|
}
|
|
return DECOMP_ERROR;
|
|
}
|
|
|
|
++db->seqno;
|
|
db->bytes_out += ilen;
|
|
|
|
if(skb_tailroom(skb_out) > 0)
|
|
*(skb_put(skb_out,1)) = 0;
|
|
else
|
|
return DECOMP_ERR_NOMEM;
|
|
|
|
oldcode = CLEAR;
|
|
|
|
/*
|
|
* Keep the checkpoint correctly so that incompressible packets
|
|
* clear the dictionary at the proper times.
|
|
*/
|
|
|
|
for (;;) {
|
|
if (ilen-- <= 0) {
|
|
db->in_count += (skb_out->len - 1); /* don't count the header */
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* 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 |= *ibuf++ << bitno;
|
|
if (tgtbitno < bitno)
|
|
continue;
|
|
|
|
incode = accm >> tgtbitno;
|
|
accm <<= n_bits;
|
|
bitno += n_bits;
|
|
|
|
/*
|
|
* The dictionary must only be cleared at the end of a packet.
|
|
*/
|
|
|
|
if (incode == CLEAR) {
|
|
if (ilen > 0) {
|
|
if (db->debug)
|
|
printk(KERN_DEBUG "bsd_decomp%d: bad CLEAR\n", db->unit);
|
|
return DECOMP_FATALERROR; /* probably a bug */
|
|
}
|
|
bsd_clear(db);
|
|
break;
|
|
}
|
|
|
|
if ((incode > max_ent + 2) || (incode > db->maxmaxcode)
|
|
|| (incode > max_ent && oldcode == CLEAR)) {
|
|
if (db->debug) {
|
|
printk(KERN_DEBUG "bsd_decomp%d: bad code 0x%x oldcode=0x%x ",
|
|
db->unit, incode, oldcode);
|
|
printk(KERN_DEBUG "max_ent=0x%x skb->Len=%d seqno=%d\n",
|
|
max_ent, skb_out->len, 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 = *(lens_ptr (db, finchar));
|
|
if( skb_tailroom(skb_out) < codelen + extra) {
|
|
if (db->debug) {
|
|
printk(KERN_DEBUG "bsd_decomp%d: ran out of mru\n", db->unit);
|
|
#ifdef DEBUG
|
|
printk(KERN_DEBUG " len=%d, finchar=0x%x, codelen=%d,skblen=%d\n",
|
|
ilen, finchar, codelen, skb_out->len);
|
|
#endif
|
|
}
|
|
return DECOMP_FATALERROR;
|
|
}
|
|
|
|
/*
|
|
* Decode this code and install it in the decompressed buffer.
|
|
*/
|
|
|
|
p = skb_put(skb_out,codelen);
|
|
p += codelen;
|
|
while (finchar > LAST) {
|
|
struct bsd_dict *dictp2 = dict_ptr (db, finchar);
|
|
|
|
dictp = dict_ptr (db, dictp2->cptr);
|
|
|
|
#ifdef DEBUG
|
|
if (--codelen <= 0 || dictp->codem1 != finchar-1) {
|
|
if (codelen <= 0) {
|
|
printk(KERN_ERR "bsd_decomp%d: fell off end of chain ", db->unit);
|
|
printk(KERN_ERR "0x%x at 0x%x by 0x%x, max_ent=0x%x\n", incode, finchar, dictp2->cptr, max_ent);
|
|
} else {
|
|
if (dictp->codem1 != finchar-1) {
|
|
printk(KERN_ERR "bsd_decomp%d: bad code chain 0x%x finchar=0x%x ",db->unit, incode, finchar);
|
|
printk(KERN_ERR "oldcode=0x%x cptr=0x%x codem1=0x%x\n", oldcode, dictp2->cptr, dictp->codem1);
|
|
}
|
|
}
|
|
return DECOMP_FATALERROR;
|
|
}
|
|
#endif
|
|
|
|
{
|
|
u32 fcode = dictp->fcode;
|
|
*--p = (fcode >> 16) & 0xff;
|
|
finchar = fcode & 0xffff;
|
|
}
|
|
}
|
|
*--p = finchar;
|
|
|
|
#ifdef DEBUG
|
|
if (--codelen != 0)
|
|
printk(KERN_ERR "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 */
|
|
*(skb_put(skb_out,1)) = 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, *dictp3;
|
|
u16 *lens1, *lens2;
|
|
unsigned long fcode;
|
|
int hval, disp, indx;
|
|
|
|
fcode = BSD_KEY(oldcode,finchar);
|
|
hval = BSD_HASH(oldcode,finchar,db->hshift);
|
|
dictp = dict_ptr (db, 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 = dict_ptr (db, hval);
|
|
} while (dictp->codem1 < max_ent);
|
|
}
|
|
|
|
/*
|
|
* Invalidate previous hash table entry
|
|
* assigned this code, and then take it over
|
|
*/
|
|
|
|
dictp2 = dict_ptr (db, max_ent + 1);
|
|
indx = dictp2->cptr;
|
|
dictp3 = dict_ptr (db, indx);
|
|
|
|
if (dictp3->codem1 == max_ent)
|
|
dictp3->codem1 = BADCODEM1;
|
|
|
|
dictp2->cptr = hval;
|
|
dictp->codem1 = max_ent;
|
|
dictp->fcode = fcode;
|
|
db->max_ent = ++max_ent;
|
|
|
|
/* Update the length of this string. */
|
|
lens1 = lens_ptr (db, max_ent);
|
|
lens2 = lens_ptr (db, oldcode);
|
|
*lens1 = *lens2 + 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;
|
|
}
|
|
|
|
++db->comp_count;
|
|
++db->uncomp_count;
|
|
db->comp_bytes += skb_in->len - BSD_OVHD;
|
|
db->uncomp_bytes += skb_out->len;
|
|
|
|
if (bsd_check(db)) {
|
|
if (db->debug)
|
|
printk(KERN_DEBUG "bsd_decomp%d: peer should have cleared dictionary on %d\n",
|
|
db->unit, db->seqno - 1);
|
|
}
|
|
return skb_out->len;
|
|
}
|
|
|
|
/*************************************************************
|
|
* Table of addresses for the BSD compression module
|
|
*************************************************************/
|
|
|
|
static struct isdn_ppp_compressor ippp_bsd_compress = {
|
|
.owner = THIS_MODULE,
|
|
.num = CI_BSD_COMPRESS,
|
|
.alloc = bsd_alloc,
|
|
.free = bsd_free,
|
|
.init = bsd_init,
|
|
.reset = bsd_reset,
|
|
.compress = bsd_compress,
|
|
.decompress = bsd_decompress,
|
|
.incomp = bsd_incomp,
|
|
.stat = bsd_stats,
|
|
};
|
|
|
|
/*************************************************************
|
|
* Module support routines
|
|
*************************************************************/
|
|
|
|
static int __init isdn_bsdcomp_init(void)
|
|
{
|
|
int answer = isdn_ppp_register_compressor (&ippp_bsd_compress);
|
|
if (answer == 0)
|
|
printk (KERN_INFO "PPP BSD Compression module registered\n");
|
|
return answer;
|
|
}
|
|
|
|
static void __exit isdn_bsdcomp_exit(void)
|
|
{
|
|
isdn_ppp_unregister_compressor (&ippp_bsd_compress);
|
|
}
|
|
|
|
module_init(isdn_bsdcomp_init);
|
|
module_exit(isdn_bsdcomp_exit);
|