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