1/* 2 * ppp-comp.h - Definitions for doing PPP packet compression. 3 * 4 * Copyright (c) 1984 Paul Mackerras. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 18 * 3. The name(s) of the authors of this software must not be used to 19 * endorse or promote products derived from this software without 20 * prior written permission. 21 * 22 * 4. Redistributions of any form whatsoever must retain the following 23 * acknowledgment: 24 * "This product includes software developed by Paul Mackerras 25 * <paulus@samba.org>". 26 * 27 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO 28 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 29 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY 30 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 31 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN 32 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING 33 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 34 * 35 * $Id: ppp-comp.h,v 1.10 2002/12/06 09:49:15 paulus Exp $ 36 */ 37 38/* 39 * ==FILEVERSION 20020715== 40 * 41 * NOTE TO MAINTAINERS: 42 * If you modify this file at all, please set the above date. 43 * ppp-comp.h is shipped with a PPP distribution as well as with the kernel; 44 * if everyone increases the FILEVERSION number above, then scripts 45 * can do the right thing when deciding whether to install a new ppp-comp.h 46 * file. Don't change the format of that line otherwise, so the 47 * installation script can recognize it. 48 */ 49 50#ifndef _NET_PPP_COMP_H 51#define _NET_PPP_COMP_H 52 53/* 54 * The following symbols control whether we include code for 55 * various compression methods. 56 */ 57 58#ifndef DO_BSD_COMPRESS 59#define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */ 60#endif 61#ifndef DO_DEFLATE 62#define DO_DEFLATE 1 /* by default, include Deflate */ 63#endif 64#define DO_PREDICTOR_1 0 65#define DO_PREDICTOR_2 0 66 67/* 68 * Structure giving methods for compression/decompression. 69 */ 70 71struct compressor { 72 int compress_proto; /* CCP compression protocol number */ 73 74 /* Allocate space for a compressor (transmit side) */ 75 void *(*comp_alloc) (unsigned char *options, int opt_len); 76 77 /* Free space used by a compressor */ 78 void (*comp_free) (void *state); 79 80 /* Initialize a compressor */ 81 int (*comp_init) (void *state, unsigned char *options, 82 int opt_len, int unit, int opthdr, int debug); 83 84 /* Reset a compressor */ 85 void (*comp_reset) (void *state); 86 87 /* Compress a packet */ 88 int (*compress) (void *state, unsigned char *rptr, 89 unsigned char *obuf, int isize, int osize); 90 91 /* Return compression statistics */ 92 void (*comp_stat) (void *state, struct compstat *stats); 93 94 /* Allocate space for a decompressor (receive side) */ 95 void *(*decomp_alloc) (unsigned char *options, int opt_len); 96 97 /* Free space used by a decompressor */ 98 void (*decomp_free) (void *state); 99 100 /* Initialize a decompressor */ 101 int (*decomp_init) (void *state, unsigned char *options, 102 int opt_len, int unit, int opthdr, int mru, 103 int debug); 104 105 /* Reset a decompressor */ 106 void (*decomp_reset) (void *state); 107 108 /* Decompress a packet. */ 109 int (*decompress) (void *state, unsigned char *ibuf, int isize, 110 unsigned char *obuf, int osize); 111 112 /* Update state for an incompressible packet received */ 113 void (*incomp) (void *state, unsigned char *ibuf, int icnt); 114 115 /* Return decompression statistics */ 116 void (*decomp_stat) (void *state, struct compstat *stats); 117}; 118 119/* 120 * The return value from decompress routine is the length of the 121 * decompressed packet if successful, otherwise DECOMP_ERROR 122 * or DECOMP_FATALERROR if an error occurred. 123 * 124 * We need to make this distinction so that we can disable certain 125 * useful functionality, namely sending a CCP reset-request as a result 126 * of an error detected after decompression. This is to avoid infringing 127 * a patent held by Motorola. 128 * Don't you just lurve software patents. 129 */ 130 131#define DECOMP_ERROR -1 /* error detected before decomp. */ 132#define DECOMP_FATALERROR -2 /* error detected after decomp. */ 133 134/* 135 * CCP codes. 136 */ 137 138#define CCP_CONFREQ 1 139#define CCP_CONFACK 2 140#define CCP_TERMREQ 5 141#define CCP_TERMACK 6 142#define CCP_RESETREQ 14 143#define CCP_RESETACK 15 144 145/* 146 * Max # bytes for a CCP option 147 */ 148 149#define CCP_MAX_OPTION_LENGTH 32 150 151/* 152 * Parts of a CCP packet. 153 */ 154 155#define CCP_CODE(dp) ((dp)[0]) 156#define CCP_ID(dp) ((dp)[1]) 157#define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3]) 158#define CCP_HDRLEN 4 159 160#define CCP_OPT_CODE(dp) ((dp)[0]) 161#define CCP_OPT_LENGTH(dp) ((dp)[1]) 162#define CCP_OPT_MINLEN 2 163 164/* 165 * Definitions for BSD-Compress. 166 */ 167 168#define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */ 169#define CILEN_BSD_COMPRESS 3 /* length of config. option */ 170 171/* Macros for handling the 3rd byte of the BSD-Compress config option. */ 172#define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */ 173#define BSD_VERSION(x) ((x) >> 5) /* version of option format */ 174#define BSD_CURRENT_VERSION 1 /* current version number */ 175#define BSD_MAKE_OPT(v, n) (((v) << 5) | (n)) 176 177#define BSD_MIN_BITS 9 /* smallest code size supported */ 178#define BSD_MAX_BITS 15 /* largest code size supported */ 179 180/* 181 * Definitions for Deflate. 182 */ 183 184#define CI_DEFLATE 26 /* config option for Deflate */ 185#define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */ 186#define CILEN_DEFLATE 4 /* length of its config option */ 187 188#define DEFLATE_MIN_SIZE 8 189#define DEFLATE_MAX_SIZE 15 190#define DEFLATE_METHOD_VAL 8 191#define DEFLATE_SIZE(x) (((x) >> 4) + DEFLATE_MIN_SIZE) 192#define DEFLATE_METHOD(x) ((x) & 0x0F) 193#define DEFLATE_MAKE_OPT(w) ((((w) - DEFLATE_MIN_SIZE) << 4) \ 194 + DEFLATE_METHOD_VAL) 195#define DEFLATE_CHK_SEQUENCE 0 196 197/* 198 * Definitions for MPPE. 199 */ 200 201#define CI_MPPE 18 /* config option for MPPE */ 202#define CILEN_MPPE 6 /* length of config option */ 203 204/* MPPE/MPPC definitions by J.D.*/ 205#define MPPE_STATELESS MPPE_H_BIT /* configuration bit H */ 206#define MPPE_40BIT MPPE_L_BIT /* configuration bit L */ 207#define MPPE_56BIT MPPE_M_BIT /* configuration bit M */ 208#define MPPE_128BIT MPPE_S_BIT /* configuration bit S */ 209#define MPPE_MPPC MPPE_C_BIT /* configuration bit C */ 210 211/* 212 * Definitions for Stac LZS. 213 */ 214 215#define CI_LZS 17 /* config option for Stac LZS */ 216#define CILEN_LZS 5 /* length of config option */ 217 218#define LZS_OVHD 4 /* max. LZS overhead */ 219#define LZS_HIST_LEN 2048 /* LZS history size */ 220#define LZS_MAX_CCOUNT 0x0FFF /* max. coherency counter value */ 221 222#define LZS_MODE_NONE 0 223#define LZS_MODE_LCB 1 224#define LZS_MODE_CRC 2 225#define LZS_MODE_SEQ 3 226#define LZS_MODE_EXT 4 227 228#define LZS_EXT_BIT_FLUSHED 0x80 /* bit A */ 229#define LZS_EXT_BIT_COMP 0x20 /* bit C */ 230 231/* 232 * Definitions for other, as yet unsupported, compression methods. 233 */ 234 235#define CI_PREDICTOR_1 1 /* config option for Predictor-1 */ 236#define CILEN_PREDICTOR_1 2 /* length of its config option */ 237#define CI_PREDICTOR_2 2 /* config option for Predictor-2 */ 238#define CILEN_PREDICTOR_2 2 /* length of its config option */ 239 240#endif /* _NET_PPP_COMP_H */ 241