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 1.6 1997/11/27 06:04:44 paulus Exp $ 28 */ 29 30 /* 31 * ==FILEVERSION 980319== 32 * 33 * NOTE TO MAINTAINERS: 34 * If you modify this file at all, please set the above date. 35 * ppp-comp.h is shipped with a PPP distribution as well as with the kernel; 36 * if everyone increases the FILEVERSION number above, then scripts 37 * can do the right thing when deciding whether to install a new ppp-comp.h 38 * file. Don't change the format of that line otherwise, so the 39 * installation script can recognize it. 40 */ 41 42 #ifndef _NET_PPP_COMP_H 43 #define _NET_PPP_COMP_H 44 45 struct module; 46 47 /* 48 * The following symbols control whether we include code for 49 * various compression methods. 50 */ 51 52 #ifndef DO_BSD_COMPRESS 53 #define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */ 54 #endif 55 #ifndef DO_DEFLATE 56 #define DO_DEFLATE 1 /* by default, include Deflate */ 57 #endif 58 #define DO_PREDICTOR_1 0 59 #define DO_PREDICTOR_2 0 60 61 /* 62 * Structure giving methods for compression/decompression. 63 */ 64 65 struct compressor { 66 int compress_proto; /* CCP compression protocol number */ 67 68 /* Allocate space for a compressor (transmit side) */ 69 void *(*comp_alloc) (unsigned char *options, int opt_len); 70 71 /* Free space used by a compressor */ 72 void (*comp_free) (void *state); 73 74 /* Initialize a compressor */ 75 int (*comp_init) (void *state, unsigned char *options, 76 int opt_len, int unit, int opthdr, int debug); 77 78 /* Reset a compressor */ 79 void (*comp_reset) (void *state); 80 81 /* Compress a packet */ 82 int (*compress) (void *state, unsigned char *rptr, 83 unsigned char *obuf, int isize, int osize); 84 85 /* Return compression statistics */ 86 void (*comp_stat) (void *state, struct compstat *stats); 87 88 /* Allocate space for a decompressor (receive side) */ 89 void *(*decomp_alloc) (unsigned char *options, int opt_len); 90 91 /* Free space used by a decompressor */ 92 void (*decomp_free) (void *state); 93 94 /* Initialize a decompressor */ 95 int (*decomp_init) (void *state, unsigned char *options, 96 int opt_len, int unit, int opthdr, int mru, 97 int debug); 98 99 /* Reset a decompressor */ 100 void (*decomp_reset) (void *state); 101 102 /* Decompress a packet. */ 103 int (*decompress) (void *state, unsigned char *ibuf, int isize, 104 unsigned char *obuf, int osize); 105 106 /* Update state for an incompressible packet received */ 107 void (*incomp) (void *state, unsigned char *ibuf, int icnt); 108 109 /* Return decompression statistics */ 110 void (*decomp_stat) (void *state, struct compstat *stats); 111 112 /* Used in locking compressor modules */ 113 struct module *owner; 114 /* Extra skb space needed by the compressor algorithm */ 115 unsigned int comp_extra; 116 }; 117 118 /* 119 * The return value from decompress routine is the length of the 120 * decompressed packet if successful, otherwise DECOMP_ERROR 121 * or DECOMP_FATALERROR if an error occurred. 122 * 123 * We need to make this distinction so that we can disable certain 124 * useful functionality, namely sending a CCP reset-request as a result 125 * of an error detected after decompression. This is to avoid infringing 126 * a patent held by Motorola. 127 * Don't you just lurve software patents. 128 */ 129 130 #define DECOMP_ERROR -1 /* error detected before decomp. */ 131 #define DECOMP_FATALERROR -2 /* error detected after decomp. */ 132 133 /* 134 * CCP codes. 135 */ 136 137 #define CCP_CONFREQ 1 138 #define CCP_CONFACK 2 139 #define CCP_TERMREQ 5 140 #define CCP_TERMACK 6 141 #define CCP_RESETREQ 14 142 #define CCP_RESETACK 15 143 144 /* 145 * Max # bytes for a CCP option 146 */ 147 148 #define CCP_MAX_OPTION_LENGTH 32 149 150 /* 151 * Parts of a CCP packet. 152 */ 153 154 #define CCP_CODE(dp) ((dp)[0]) 155 #define CCP_ID(dp) ((dp)[1]) 156 #define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3]) 157 #define CCP_HDRLEN 4 158 159 #define CCP_OPT_CODE(dp) ((dp)[0]) 160 #define CCP_OPT_LENGTH(dp) ((dp)[1]) 161 #define CCP_OPT_MINLEN 2 162 163 /* 164 * Definitions for BSD-Compress. 165 */ 166 167 #define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */ 168 #define CILEN_BSD_COMPRESS 3 /* length of config. option */ 169 170 /* Macros for handling the 3rd byte of the BSD-Compress config option. */ 171 #define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */ 172 #define BSD_VERSION(x) ((x) >> 5) /* version of option format */ 173 #define BSD_CURRENT_VERSION 1 /* current version number */ 174 #define BSD_MAKE_OPT(v, n) (((v) << 5) | (n)) 175 176 #define BSD_MIN_BITS 9 /* smallest code size supported */ 177 #define BSD_MAX_BITS 15 /* largest code size supported */ 178 179 /* 180 * Definitions for Deflate. 181 */ 182 183 #define CI_DEFLATE 26 /* config option for Deflate */ 184 #define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */ 185 #define CILEN_DEFLATE 4 /* length of its config option */ 186 187 #define DEFLATE_MIN_SIZE 9 188 #define DEFLATE_MAX_SIZE 15 189 #define DEFLATE_METHOD_VAL 8 190 #define DEFLATE_SIZE(x) (((x) >> 4) + 8) 191 #define DEFLATE_METHOD(x) ((x) & 0x0F) 192 #define DEFLATE_MAKE_OPT(w) ((((w) - 8) << 4) + DEFLATE_METHOD_VAL) 193 #define DEFLATE_CHK_SEQUENCE 0 194 195 /* 196 * Definitions for MPPE. 197 */ 198 199 #define CI_MPPE 18 /* config option for MPPE */ 200 #define CILEN_MPPE 6 /* length of config option */ 201 202 /* 203 * Definitions for other, as yet unsupported, compression methods. 204 */ 205 206 #define CI_PREDICTOR_1 1 /* config option for Predictor-1 */ 207 #define CILEN_PREDICTOR_1 2 /* length of its config option */ 208 #define CI_PREDICTOR_2 2 /* config option for Predictor-2 */ 209 #define CILEN_PREDICTOR_2 2 /* length of its config option */ 210 211 212 #endif /* _NET_PPP_COMP_H */ 213