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/*
* ppp-comp.h - Definitions for doing PPP packet compression.
*
* Copyright 1994-1998 Paul Mackerras.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*/
#ifndef _NET_PPP_COMP_H
#define _NET_PPP_COMP_H
struct module;
/*
* The following symbols control whether we include code for
* various compression methods.
*/
#ifndef DO_BSD_COMPRESS
#define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */
#endif
#ifndef DO_DEFLATE
#define DO_DEFLATE 1 /* by default, include Deflate */
#endif
#define DO_PREDICTOR_1 0
#define DO_PREDICTOR_2 0
/*
* Structure giving methods for compression/decompression.
*/
struct compressor {
int compress_proto; /* CCP compression protocol number */
/* Allocate space for a compressor (transmit side) */
void *(*comp_alloc) (unsigned char *options, int opt_len);
/* Free space used by a compressor */
void (*comp_free) (void *state);
/* Initialize a compressor */
int (*comp_init) (void *state, unsigned char *options,
int opt_len, int unit, int opthdr, int debug);
/* Reset a compressor */
void (*comp_reset) (void *state);
/* Compress a packet */
int (*compress) (void *state, unsigned char *rptr,
unsigned char *obuf, int isize, int osize);
/* Return compression statistics */
void (*comp_stat) (void *state, struct compstat *stats);
/* Allocate space for a decompressor (receive side) */
void *(*decomp_alloc) (unsigned char *options, int opt_len);
/* Free space used by a decompressor */
void (*decomp_free) (void *state);
/* Initialize a decompressor */
int (*decomp_init) (void *state, unsigned char *options,
int opt_len, int unit, int opthdr, int mru,
int debug);
/* Reset a decompressor */
void (*decomp_reset) (void *state);
/* Decompress a packet. */
int (*decompress) (void *state, unsigned char *ibuf, int isize,
unsigned char *obuf, int osize);
/* Update state for an incompressible packet received */
void (*incomp) (void *state, unsigned char *ibuf, int icnt);
/* Return decompression statistics */
void (*decomp_stat) (void *state, struct compstat *stats);
/* Used in locking compressor modules */
struct module *owner;
/* Extra skb space needed by the compressor algorithm */
unsigned int comp_extra;
};
/*
* The return value from decompress routine is the length of the
* decompressed packet if successful, otherwise DECOMP_ERROR
* or DECOMP_FATALERROR if an error occurred.
*
* We need to make this distinction so that we can disable certain
* useful functionality, namely sending a CCP reset-request as a result
* of an error detected after decompression. This is to avoid infringing
* a patent held by Motorola.
* Don't you just lurve software patents.
*/
#define DECOMP_ERROR -1 /* error detected before decomp. */
#define DECOMP_FATALERROR -2 /* error detected after decomp. */
/*
* CCP codes.
*/
#define CCP_CONFREQ 1
#define CCP_CONFACK 2
#define CCP_TERMREQ 5
#define CCP_TERMACK 6
#define CCP_RESETREQ 14
#define CCP_RESETACK 15
/*
* Max # bytes for a CCP option
*/
#define CCP_MAX_OPTION_LENGTH 32
/*
* Parts of a CCP packet.
*/
#define CCP_CODE(dp) ((dp)[0])
#define CCP_ID(dp) ((dp)[1])
#define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3])
#define CCP_HDRLEN 4
#define CCP_OPT_CODE(dp) ((dp)[0])
#define CCP_OPT_LENGTH(dp) ((dp)[1])
#define CCP_OPT_MINLEN 2
/*
* Definitions for BSD-Compress.
*/
#define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */
#define CILEN_BSD_COMPRESS 3 /* length of config. option */
/* Macros for handling the 3rd byte of the BSD-Compress config option. */
#define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */
#define BSD_VERSION(x) ((x) >> 5) /* version of option format */
#define BSD_CURRENT_VERSION 1 /* current version number */
#define BSD_MAKE_OPT(v, n) (((v) << 5) | (n))
#define BSD_MIN_BITS 9 /* smallest code size supported */
#define BSD_MAX_BITS 15 /* largest code size supported */
/*
* Definitions for Deflate.
*/
#define CI_DEFLATE 26 /* config option for Deflate */
#define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */
#define CILEN_DEFLATE 4 /* length of its config option */
#define DEFLATE_MIN_SIZE 9
#define DEFLATE_MAX_SIZE 15
#define DEFLATE_METHOD_VAL 8
#define DEFLATE_SIZE(x) (((x) >> 4) + 8)
#define DEFLATE_METHOD(x) ((x) & 0x0F)
#define DEFLATE_MAKE_OPT(w) ((((w) - 8) << 4) + DEFLATE_METHOD_VAL)
#define DEFLATE_CHK_SEQUENCE 0
/*
* Definitions for MPPE.
*/
#define CI_MPPE 18 /* config option for MPPE */
#define CILEN_MPPE 6 /* length of config option */
/*
* Definitions for other, as yet unsupported, compression methods.
*/
#define CI_PREDICTOR_1 1 /* config option for Predictor-1 */
#define CILEN_PREDICTOR_1 2 /* length of its config option */
#define CI_PREDICTOR_2 2 /* config option for Predictor-2 */
#define CILEN_PREDICTOR_2 2 /* length of its config option */
#ifdef __KERNEL__
extern int ppp_register_compressor(struct compressor *);
extern void ppp_unregister_compressor(struct compressor *);
#endif /* __KERNEL__ */
#endif /* _NET_PPP_COMP_H */
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