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 43struct 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 63struct 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 */ 208 209 210#endif /* _NET_PPP_COMP_H */ 211