include/linux/ppp-comp.h

   1 /*
   2  * ppp-comp.h - Definitions for doing PPP packet compression.
   3  *
   4  * Copyright 1994-1998 Paul Mackerras.
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License
   8  *  version 2 as published by the Free Software Foundation.
   9  */
  10 #ifndef _NET_PPP_COMP_H
  11 #define _NET_PPP_COMP_H
  12
  13 #include <uapi/linux/ppp-comp.h>
  14
  15
  16 struct module;
  17
  18 /*
  19  * The following symbols control whether we include code for
  20  * various compression methods.
  21  */
  22
  23 #ifndef DO_BSD_COMPRESS
  24 #define DO_BSD_COMPRESS 1       /* by default, include BSD-Compress */
  25 #endif
  26 #ifndef DO_DEFLATE
  27 #define DO_DEFLATE      1       /* by default, include Deflate */
  28 #endif
  29 #define DO_PREDICTOR_1  0
  30 #define DO_PREDICTOR_2  0
  31
  32 /*
  33  * Structure giving methods for compression/decompression.
  34  */
  35
  36 struct compressor {
  37         int     compress_proto; /* CCP compression protocol number */
  38
  39         /* Allocate space for a compressor (transmit side) */
  40         void    *(*comp_alloc) (unsigned char *options, int opt_len);
  41
  42         /* Free space used by a compressor */
  43         void    (*comp_free) (void *state);
  44
  45         /* Initialize a compressor */
  46         int     (*comp_init) (void *state, unsigned char *options,
  47                               int opt_len, int unit, int opthdr, int debug);
  48
  49         /* Reset a compressor */
  50         void    (*comp_reset) (void *state);
  51
  52         /* Compress a packet */
  53         int     (*compress) (void *state, unsigned char *rptr,
  54                               unsigned char *obuf, int isize, int osize);
  55
  56         /* Return compression statistics */
  57         void    (*comp_stat) (void *state, struct compstat *stats);
  58
  59         /* Allocate space for a decompressor (receive side) */
  60         void    *(*decomp_alloc) (unsigned char *options, int opt_len);
  61
  62         /* Free space used by a decompressor */
  63         void    (*decomp_free) (void *state);
  64
  65         /* Initialize a decompressor */
  66         int     (*decomp_init) (void *state, unsigned char *options,
  67                                 int opt_len, int unit, int opthdr, int mru,
  68                                 int debug);
  69
  70         /* Reset a decompressor */
  71         void    (*decomp_reset) (void *state);
  72
  73         /* Decompress a packet. */
  74         int     (*decompress) (void *state, unsigned char *ibuf, int isize,
  75                                 unsigned char *obuf, int osize);
  76
  77         /* Update state for an incompressible packet received */
  78         void    (*incomp) (void *state, unsigned char *ibuf, int icnt);
  79
  80         /* Return decompression statistics */
  81         void    (*decomp_stat) (void *state, struct compstat *stats);
  82
  83         /* Used in locking compressor modules */
  84         struct module *owner;
  85         /* Extra skb space needed by the compressor algorithm */
  86         unsigned int comp_extra;
  87 };
  88
  89 /*
  90  * The return value from decompress routine is the length of the
  91  * decompressed packet if successful, otherwise DECOMP_ERROR
  92  * or DECOMP_FATALERROR if an error occurred.
  93  *
  94  * We need to make this distinction so that we can disable certain
  95  * useful functionality, namely sending a CCP reset-request as a result
  96  * of an error detected after decompression.  This is to avoid infringing
  97  * a patent held by Motorola.
  98  * Don't you just lurve software patents.
  99  */
 100
 101 #define DECOMP_ERROR            -1      /* error detected before decomp. */
 102 #define DECOMP_FATALERROR       -2      /* error detected after decomp. */
 103
 104 extern int ppp_register_compressor(struct compressor *);
 105 extern void ppp_unregister_compressor(struct compressor *);
 106 #endif /* _NET_PPP_COMP_H */