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- /* SPDX-License-Identifier: GPL-2.0-only */
- /*
- * ppp-comp.h - Definitions for doing PPP packet compression.
- *
- * Copyright 1994-1998 Paul Mackerras.
- */
- #ifndef _NET_PPP_COMP_H
- #define _NET_PPP_COMP_H
- #include <uapi/linux/ppp-comp.h>
- struct compstat;
- 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. */
- extern int ppp_register_compressor(struct compressor *);
- extern void ppp_unregister_compressor(struct compressor *);
- #endif /* _NET_PPP_COMP_H */
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