sys/net/ppp_layer/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  * $FreeBSD: src/sys/net/ppp_comp.h,v 1.8 1999/08/28 00:48:25 peter Exp $
  28  * $DragonFly: src/sys/net/ppp_layer/ppp_comp.h,v 1.3 2003/08/26 20:49:48 rob Exp $
  29  */
  30
  31 #ifndef _NET_PPP_COMP_H
  32 #define _NET_PPP_COMP_H
  33
  34 /*
  35  * The following symbols control whether we include code for
  36  * various compression methods.
  37  */
  38 #ifndef DO_BSD_COMPRESS
  39 #define DO_BSD_COMPRESS 1       /* by default, include BSD-Compress */
  40 #endif
  41 #ifndef DO_DEFLATE
  42 #define DO_DEFLATE      1       /* by default, include Deflate */
  43 #endif
  44 #define DO_PREDICTOR_1  0
  45 #define DO_PREDICTOR_2  0
  46
  47 /*
  48  * Structure giving methods for compression/decompression.
  49  */
  50 #ifdef PACKETPTR
  51 struct compressor {
  52         int     compress_proto; /* CCP compression protocol number */
  53
  54         /* Allocate space for a compressor (transmit side) */
  55         void    *(*comp_alloc) (u_char *options, int opt_len);
  56         /* Free space used by a compressor */
  57         void    (*comp_free) (void *state);
  58         /* Initialize a compressor */
  59         int     (*comp_init) (void *state, u_char *options, int opt_len,
  60                                   int unit, int hdrlen, int debug);
  61         /* Reset a compressor */
  62         void    (*comp_reset) (void *state);
  63         /* Compress a packet */
  64         int     (*compress) (void *state, PACKETPTR *mret,
  65                                  PACKETPTR mp, int orig_len, int max_len);
  66         /* Return compression statistics */
  67         void    (*comp_stat) (void *state, struct compstat *stats);
  68
  69         /* Allocate space for a decompressor (receive side) */
  70         void    *(*decomp_alloc) (u_char *options, int opt_len);
  71         /* Free space used by a decompressor */
  72         void    (*decomp_free) (void *state);
  73         /* Initialize a decompressor */
  74         int     (*decomp_init) (void *state, u_char *options, int opt_len,
  75                                     int unit, int hdrlen, int mru, int debug);
  76         /* Reset a decompressor */
  77         void    (*decomp_reset) (void *state);
  78         /* Decompress a packet. */
  79         int     (*decompress) (void *state, PACKETPTR mp,
  80                                    PACKETPTR *dmpp);
  81         /* Update state for an incompressible packet received */
  82         void    (*incomp) (void *state, PACKETPTR mp);
  83         /* Return decompression statistics */
  84         void    (*decomp_stat) (void *state, struct compstat *stats);
  85 };
  86 #endif /* PACKETPTR */
  87
  88 /*
  89  * Return values for decompress routine.
  90  * We need to make these distinctions so that we can disable certain
  91  * useful functionality, namely sending a CCP reset-request as a result
  92  * of an error detected after decompression.  This is to avoid infringing
  93  * a patent held by Motorola.
  94  * Don't you just lurve software patents.
  95  */
  96 #define DECOMP_OK               0       /* everything went OK */
  97 #define DECOMP_ERROR            1       /* error detected before decomp. */
  98 #define DECOMP_FATALERROR       2       /* error detected after decomp. */
  99
 100 /*
 101  * CCP codes.
 102  */
 103 #define CCP_CONFREQ     1
 104 #define CCP_CONFACK     2
 105 #define CCP_TERMREQ     5
 106 #define CCP_TERMACK     6
 107 #define CCP_RESETREQ    14
 108 #define CCP_RESETACK    15
 109
 110 /*
 111  * Max # bytes for a CCP option
 112  */
 113 #define CCP_MAX_OPTION_LENGTH   32
 114
 115 /*
 116  * Parts of a CCP packet.
 117  */
 118 #define CCP_CODE(dp)            ((dp)[0])
 119 #define CCP_ID(dp)              ((dp)[1])
 120 #define CCP_LENGTH(dp)          (((dp)[2] << 8) + (dp)[3])
 121 #define CCP_HDRLEN              4
 122
 123 #define CCP_OPT_CODE(dp)        ((dp)[0])
 124 #define CCP_OPT_LENGTH(dp)      ((dp)[1])
 125 #define CCP_OPT_MINLEN          2
 126
 127 /*
 128  * Definitions for BSD-Compress.
 129  */
 130 #define CI_BSD_COMPRESS         21      /* config. option for BSD-Compress */
 131 #define CILEN_BSD_COMPRESS      3       /* length of config. option */
 132
 133 /* Macros for handling the 3rd byte of the BSD-Compress config option. */
 134 #define BSD_NBITS(x)            ((x) & 0x1F)    /* number of bits requested */
 135 #define BSD_VERSION(x)          ((x) >> 5)      /* version of option format */
 136 #define BSD_CURRENT_VERSION     1               /* current version number */
 137 #define BSD_MAKE_OPT(v, n)      (((v) << 5) | (n))
 138
 139 #define BSD_MIN_BITS            9       /* smallest code size supported */
 140 #define BSD_MAX_BITS            15      /* largest code size supported */
 141
 142 /*
 143  * Definitions for Deflate.
 144  */
 145 #define CI_DEFLATE              26      /* config option for Deflate */
 146 #define CI_DEFLATE_DRAFT        24      /* value used in original draft RFC */
 147 #define CILEN_DEFLATE           4       /* length of its config option */
 148
 149 #define DEFLATE_MIN_SIZE        8
 150 #define DEFLATE_MAX_SIZE        15
 151 #define DEFLATE_METHOD_VAL      8
 152 #define DEFLATE_SIZE(x)         (((x) >> 4) + DEFLATE_MIN_SIZE)
 153 #define DEFLATE_METHOD(x)       ((x) & 0x0F)
 154 #define DEFLATE_MAKE_OPT(w)     ((((w) - DEFLATE_MIN_SIZE) << 4) \
 155                                  + DEFLATE_METHOD_VAL)
 156 #define DEFLATE_CHK_SEQUENCE    0
 157
 158 /*
 159  * Definitions for other, as yet unsupported, compression methods.
 160  */
 161 #define CI_PREDICTOR_1          1       /* config option for Predictor-1 */
 162 #define CILEN_PREDICTOR_1       2       /* length of its config option */
 163 #define CI_PREDICTOR_2          2       /* config option for Predictor-2 */
 164 #define CILEN_PREDICTOR_2       2       /* length of its config option */
 165
 166 #endif /* _NET_PPP_COMP_H */