release/src/router/ppp/include/net/ppp-comp.h

   1 /*
   2  * ppp-comp.h - Definitions for doing PPP packet compression.
   3  *
   4  * Copyright (c) 1994 The Australian National University.
   5  * All rights reserved.
   6  *
   7  * Permission to use, copy, modify, and distribute this software and its
   8  * documentation is hereby granted, provided that the above copyright
   9  * notice appears in all copies.  This software is provided without any
  10  * warranty, express or implied. The Australian National University
  11  * makes no representations about the suitability of this software for
  12  * any purpose.
  13  *
  14  * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
  15  * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  16  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
  17  * THE AUSTRALIAN NATIONAL UNIVERSITY HAVE BEEN ADVISED OF THE POSSIBILITY
  18  * OF SUCH DAMAGE.
  19  *
  20  * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
  21  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  22  * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  23  * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
  24  * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
  25  * OR MODIFICATIONS.
  26  *
  27  * $Id: ppp-comp.h,v 1.1.1.4 2003/10/14 08:09:53 sparq Exp $
  28  */
  29
  30 #ifndef _NET_PPP_COMP_H
  31 #define _NET_PPP_COMP_H
  32
  33 /*
  34  * The following symbols control whether we include code for
  35  * various compression methods.
  36  */
  37 #ifndef DO_BSD_COMPRESS
  38 #define DO_BSD_COMPRESS 1       /* by default, include BSD-Compress */
  39 #endif
  40 #ifndef DO_DEFLATE
  41 #define DO_DEFLATE      1       /* by default, include Deflate */
  42 #endif
  43 #define DO_PREDICTOR_1  0
  44 #define DO_PREDICTOR_2  0
  45
  46 /*
  47  * Structure giving methods for compression/decompression.
  48  */
  49 #ifdef PACKETPTR
  50 struct compressor {
  51         int     compress_proto; /* CCP compression protocol number */
  52
  53         /* Allocate space for a compressor (transmit side) */
  54         void    *(*comp_alloc) __P((u_char *options, int opt_len));
  55         /* Free space used by a compressor */
  56         void    (*comp_free) __P((void *state));
  57         /* Initialize a compressor */
  58         int     (*comp_init) __P((void *state, u_char *options, int opt_len,
  59                                   int unit, int hdrlen, int debug));
  60         /* Reset a compressor */
  61         void    (*comp_reset) __P((void *state));
  62         /* Compress a packet */
  63         int     (*compress) __P((void *state, PACKETPTR *mret,
  64                                  PACKETPTR mp, int orig_len, int max_len));
  65         /* Return compression statistics */
  66         void    (*comp_stat) __P((void *state, struct compstat *stats));
  67
  68         /* Allocate space for a decompressor (receive side) */
  69         void    *(*decomp_alloc) __P((u_char *options, int opt_len));
  70         /* Free space used by a decompressor */
  71         void    (*decomp_free) __P((void *state));
  72         /* Initialize a decompressor */
  73         int     (*decomp_init) __P((void *state, u_char *options, int opt_len,
  74                                     int unit, int hdrlen, int mru, int debug));
  75         /* Reset a decompressor */
  76         void    (*decomp_reset) __P((void *state));
  77         /* Decompress a packet. */
  78         int     (*decompress) __P((void *state, PACKETPTR mp,
  79                                    PACKETPTR *dmpp));
  80         /* Update state for an incompressible packet received */
  81         void    (*incomp) __P((void *state, PACKETPTR mp));
  82         /* Return decompression statistics */
  83         void    (*decomp_stat) __P((void *state, struct compstat *stats));
  84 };
  85 #endif /* PACKETPTR */
  86
  87 /*
  88  * Return values for decompress routine.
  89  * We need to make these distinctions so that we can disable certain
  90  * useful functionality, namely sending a CCP reset-request as a result
  91  * of an error detected after decompression.  This is to avoid infringing
  92  * a patent held by Motorola.
  93  * Don't you just lurve software patents.
  94  */
  95 #define DECOMP_OK               0       /* everything went OK */
  96 #define DECOMP_ERROR            1       /* error detected before decomp. */
  97 #define DECOMP_FATALERROR       2       /* error detected after decomp. */
  98
  99 /*
 100  * CCP codes.
 101  */
 102 #define CCP_CONFREQ     1
 103 #define CCP_CONFACK     2
 104 #define CCP_TERMREQ     5
 105 #define CCP_TERMACK     6
 106 #define CCP_RESETREQ    14
 107 #define CCP_RESETACK    15
 108
 109 /*
 110  * Max # bytes for a CCP option
 111  */
 112 #define CCP_MAX_OPTION_LENGTH   32
 113
 114 /*
 115  * Parts of a CCP packet.
 116  */
 117 #define CCP_CODE(dp)            ((dp)[0])
 118 #define CCP_ID(dp)              ((dp)[1])
 119 #define CCP_LENGTH(dp)          (((dp)[2] << 8) + (dp)[3])
 120 #define CCP_HDRLEN              4
 121
 122 #define CCP_OPT_CODE(dp)        ((dp)[0])
 123 #define CCP_OPT_LENGTH(dp)      ((dp)[1])
 124 #define CCP_OPT_MINLEN          2
 125
 126 /*
 127  * Definitions for BSD-Compress.
 128  */
 129 #define CI_BSD_COMPRESS         21      /* config. option for BSD-Compress */
 130 #define CILEN_BSD_COMPRESS      3       /* length of config. option */
 131
 132 /* Macros for handling the 3rd byte of the BSD-Compress config option. */
 133 #define BSD_NBITS(x)            ((x) & 0x1F)    /* number of bits requested */
 134 #define BSD_VERSION(x)          ((x) >> 5)      /* version of option format */
 135 #define BSD_CURRENT_VERSION     1               /* current version number */
 136 #define BSD_MAKE_OPT(v, n)      (((v) << 5) | (n))
 137
 138 #define BSD_MIN_BITS            9       /* smallest code size supported */
 139 #define BSD_MAX_BITS            15      /* largest code size supported */
 140
 141 /*
 142  * Definitions for Deflate.
 143  */
 144 #define CI_DEFLATE              26      /* config option for Deflate */
 145 #define CI_DEFLATE_DRAFT        24      /* value used in original draft RFC */
 146 #define CILEN_DEFLATE           4       /* length of its config option */
 147
 148 #define DEFLATE_MIN_SIZE        8
 149 #define DEFLATE_MAX_SIZE        15
 150 #define DEFLATE_METHOD_VAL      8
 151 #define DEFLATE_SIZE(x)         (((x) >> 4) + DEFLATE_MIN_SIZE)
 152 #define DEFLATE_METHOD(x)       ((x) & 0x0F)
 153 #define DEFLATE_MAKE_OPT(w)     ((((w) - DEFLATE_MIN_SIZE) << 4) \
 154                                  + DEFLATE_METHOD_VAL)
 155 #define DEFLATE_CHK_SEQUENCE    0
 156
 157 /*
 158  * Definitions for other, as yet unsupported, compression methods.
 159  */
 160 #define CI_PREDICTOR_1          1       /* config option for Predictor-1 */
 161 #define CILEN_PREDICTOR_1       2       /* length of its config option */
 162 #define CI_PREDICTOR_2          2       /* config option for Predictor-2 */
 163 #define CILEN_PREDICTOR_2       2       /* length of its config option */
 164
 165 #endif /* _NET_PPP_COMP_H */