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 28 /* 29 * ==FILEVERSION 980319== 30 * 31 * NOTE TO MAINTAINERS: 32 * If you modify this file at all, please set the above date. 33 * ppp-comp.h is shipped with a PPP distribution as well as with the kernel; 34 * if everyone increases the FILEVERSION number above, then scripts 35 * can do the right thing when deciding whether to install a new ppp-comp.h 36 * file. Don't change the format of that line otherwise, so the 37 * installation script can recognize it. 38 */ 39 40 #ifndef _NET_PPP_COMP_H 41 #define _NET_PPP_COMP_H 42 43 struct module; 44 45 /* 46 * The following symbols control whether we include code for 47 * various compression methods. 48 */ 49 50 #ifndef DO_BSD_COMPRESS 51 #define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */ 52 #endif 53 #ifndef DO_DEFLATE 54 #define DO_DEFLATE 1 /* by default, include Deflate */ 55 #endif 56 #define DO_PREDICTOR_1 0 57 #define DO_PREDICTOR_2 0 58 59 /* 60 * Structure giving methods for compression/decompression. 61 */ 62 63 struct compressor { 64 int compress_proto; /* CCP compression protocol number */ 65 66 /* Allocate space for a compressor (transmit side) */ 67 void *(*comp_alloc) (unsigned char *options, int opt_len); 68 69 /* Free space used by a compressor */ 70 void (*comp_free) (void *state); 71 72 /* Initialize a compressor */ 73 int (*comp_init) (void *state, unsigned char *options, 74 int opt_len, int unit, int opthdr, int debug); 75 76 /* Reset a compressor */ 77 void (*comp_reset) (void *state); 78 79 /* Compress a packet */ 80 int (*compress) (void *state, unsigned char *rptr, 81 unsigned char *obuf, int isize, int osize); 82 83 /* Return compression statistics */ 84 void (*comp_stat) (void *state, struct compstat *stats); 85 86 /* Allocate space for a decompressor (receive side) */ 87 void *(*decomp_alloc) (unsigned char *options, int opt_len); 88 89 /* Free space used by a decompressor */ 90 void (*decomp_free) (void *state); 91 92 /* Initialize a decompressor */ 93 int (*decomp_init) (void *state, unsigned char *options, 94 int opt_len, int unit, int opthdr, int mru, 95 int debug); 96 97 /* Reset a decompressor */ 98 void (*decomp_reset) (void *state); 99 100 /* Decompress a packet. */ 101 int (*decompress) (void *state, unsigned char *ibuf, int isize, 102 unsigned char *obuf, int osize); 103 104 /* Update state for an incompressible packet received */ 105 void (*incomp) (void *state, unsigned char *ibuf, int icnt); 106 107 /* Return decompression statistics */ 108 void (*decomp_stat) (void *state, struct compstat *stats); 109 110 /* Used in locking compressor modules */ 111 struct module *owner; 112 /* Extra skb space needed by the compressor algorithm */ 113 unsigned int comp_extra; 114 }; 115 116 /* 117 * The return value from decompress routine is the length of the 118 * decompressed packet if successful, otherwise DECOMP_ERROR 119 * or DECOMP_FATALERROR if an error occurred. 120 * 121 * We need to make this distinction so that we can disable certain 122 * useful functionality, namely sending a CCP reset-request as a result 123 * of an error detected after decompression. This is to avoid infringing 124 * a patent held by Motorola. 125 * Don't you just lurve software patents. 126 */ 127 128 #define DECOMP_ERROR -1 /* error detected before decomp. */ 129 #define DECOMP_FATALERROR -2 /* error detected after decomp. */ 130 131 /* 132 * CCP codes. 133 */ 134 135 #define CCP_CONFREQ 1 136 #define CCP_CONFACK 2 137 #define CCP_TERMREQ 5 138 #define CCP_TERMACK 6 139 #define CCP_RESETREQ 14 140 #define CCP_RESETACK 15 141 142 /* 143 * Max # bytes for a CCP option 144 */ 145 146 #define CCP_MAX_OPTION_LENGTH 32 147 148 /* 149 * Parts of a CCP packet. 150 */ 151 152 #define CCP_CODE(dp) ((dp)[0]) 153 #define CCP_ID(dp) ((dp)[1]) 154 #define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3]) 155 #define CCP_HDRLEN 4 156 157 #define CCP_OPT_CODE(dp) ((dp)[0]) 158 #define CCP_OPT_LENGTH(dp) ((dp)[1]) 159 #define CCP_OPT_MINLEN 2 160 161 /* 162 * Definitions for BSD-Compress. 163 */ 164 165 #define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */ 166 #define CILEN_BSD_COMPRESS 3 /* length of config. option */ 167 168 /* Macros for handling the 3rd byte of the BSD-Compress config option. */ 169 #define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */ 170 #define BSD_VERSION(x) ((x) >> 5) /* version of option format */ 171 #define BSD_CURRENT_VERSION 1 /* current version number */ 172 #define BSD_MAKE_OPT(v, n) (((v) << 5) | (n)) 173 174 #define BSD_MIN_BITS 9 /* smallest code size supported */ 175 #define BSD_MAX_BITS 15 /* largest code size supported */ 176 177 /* 178 * Definitions for Deflate. 179 */ 180 181 #define CI_DEFLATE 26 /* config option for Deflate */ 182 #define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */ 183 #define CILEN_DEFLATE 4 /* length of its config option */ 184 185 #define DEFLATE_MIN_SIZE 9 186 #define DEFLATE_MAX_SIZE 15 187 #define DEFLATE_METHOD_VAL 8 188 #define DEFLATE_SIZE(x) (((x) >> 4) + 8) 189 #define DEFLATE_METHOD(x) ((x) & 0x0F) 190 #define DEFLATE_MAKE_OPT(w) ((((w) - 8) << 4) + DEFLATE_METHOD_VAL) 191 #define DEFLATE_CHK_SEQUENCE 0 192 193 /* 194 * Definitions for MPPE. 195 */ 196 197 #define CI_MPPE 18 /* config option for MPPE */ 198 #define CILEN_MPPE 6 /* length of config option */ 199 200 /* 201 * Definitions for other, as yet unsupported, compression methods. 202 */ 203 204 #define CI_PREDICTOR_1 1 /* config option for Predictor-1 */ 205 #define CILEN_PREDICTOR_1 2 /* length of its config option */ 206 #define CI_PREDICTOR_2 2 /* config option for Predictor-2 */ 207 #define CILEN_PREDICTOR_2 2 /* length of its config option */ 208 209 #ifdef __KERNEL__ 210 extern int ppp_register_compressor(struct compressor *); 211 extern void ppp_unregister_compressor(struct compressor *); 212 #endif /* __KERNEL__ */ 213 214 #endif /* _NET_PPP_COMP_H */ 215