1 /* 2 * ppp-comp.h - Definitions for doing PPP packet compression. 3 * 4 * Copyright 1994-1998 Paul Mackerras. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * version 2 as published by the Free Software Foundation. 9 */ 10 #ifndef _NET_PPP_COMP_H 11 #define _NET_PPP_COMP_H 12 13 struct module; 14 15 /* 16 * The following symbols control whether we include code for 17 * various compression methods. 18 */ 19 20 #ifndef DO_BSD_COMPRESS 21 #define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */ 22 #endif 23 #ifndef DO_DEFLATE 24 #define DO_DEFLATE 1 /* by default, include Deflate */ 25 #endif 26 #define DO_PREDICTOR_1 0 27 #define DO_PREDICTOR_2 0 28 29 /* 30 * Structure giving methods for compression/decompression. 31 */ 32 33 struct compressor { 34 int compress_proto; /* CCP compression protocol number */ 35 36 /* Allocate space for a compressor (transmit side) */ 37 void *(*comp_alloc) (unsigned char *options, int opt_len); 38 39 /* Free space used by a compressor */ 40 void (*comp_free) (void *state); 41 42 /* Initialize a compressor */ 43 int (*comp_init) (void *state, unsigned char *options, 44 int opt_len, int unit, int opthdr, int debug); 45 46 /* Reset a compressor */ 47 void (*comp_reset) (void *state); 48 49 /* Compress a packet */ 50 int (*compress) (void *state, unsigned char *rptr, 51 unsigned char *obuf, int isize, int osize); 52 53 /* Return compression statistics */ 54 void (*comp_stat) (void *state, struct compstat *stats); 55 56 /* Allocate space for a decompressor (receive side) */ 57 void *(*decomp_alloc) (unsigned char *options, int opt_len); 58 59 /* Free space used by a decompressor */ 60 void (*decomp_free) (void *state); 61 62 /* Initialize a decompressor */ 63 int (*decomp_init) (void *state, unsigned char *options, 64 int opt_len, int unit, int opthdr, int mru, 65 int debug); 66 67 /* Reset a decompressor */ 68 void (*decomp_reset) (void *state); 69 70 /* Decompress a packet. */ 71 int (*decompress) (void *state, unsigned char *ibuf, int isize, 72 unsigned char *obuf, int osize); 73 74 /* Update state for an incompressible packet received */ 75 void (*incomp) (void *state, unsigned char *ibuf, int icnt); 76 77 /* Return decompression statistics */ 78 void (*decomp_stat) (void *state, struct compstat *stats); 79 80 /* Used in locking compressor modules */ 81 struct module *owner; 82 /* Extra skb space needed by the compressor algorithm */ 83 unsigned int comp_extra; 84 }; 85 86 /* 87 * The return value from decompress routine is the length of the 88 * decompressed packet if successful, otherwise DECOMP_ERROR 89 * or DECOMP_FATALERROR if an error occurred. 90 * 91 * We need to make this distinction so that we can disable certain 92 * useful functionality, namely sending a CCP reset-request as a result 93 * of an error detected after decompression. This is to avoid infringing 94 * a patent held by Motorola. 95 * Don't you just lurve software patents. 96 */ 97 98 #define DECOMP_ERROR -1 /* error detected before decomp. */ 99 #define DECOMP_FATALERROR -2 /* error detected after decomp. */ 100 101 /* 102 * CCP codes. 103 */ 104 105 #define CCP_CONFREQ 1 106 #define CCP_CONFACK 2 107 #define CCP_TERMREQ 5 108 #define CCP_TERMACK 6 109 #define CCP_RESETREQ 14 110 #define CCP_RESETACK 15 111 112 /* 113 * Max # bytes for a CCP option 114 */ 115 116 #define CCP_MAX_OPTION_LENGTH 32 117 118 /* 119 * Parts of a CCP packet. 120 */ 121 122 #define CCP_CODE(dp) ((dp)[0]) 123 #define CCP_ID(dp) ((dp)[1]) 124 #define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3]) 125 #define CCP_HDRLEN 4 126 127 #define CCP_OPT_CODE(dp) ((dp)[0]) 128 #define CCP_OPT_LENGTH(dp) ((dp)[1]) 129 #define CCP_OPT_MINLEN 2 130 131 /* 132 * Definitions for BSD-Compress. 133 */ 134 135 #define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */ 136 #define CILEN_BSD_COMPRESS 3 /* length of config. option */ 137 138 /* Macros for handling the 3rd byte of the BSD-Compress config option. */ 139 #define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */ 140 #define BSD_VERSION(x) ((x) >> 5) /* version of option format */ 141 #define BSD_CURRENT_VERSION 1 /* current version number */ 142 #define BSD_MAKE_OPT(v, n) (((v) << 5) | (n)) 143 144 #define BSD_MIN_BITS 9 /* smallest code size supported */ 145 #define BSD_MAX_BITS 15 /* largest code size supported */ 146 147 /* 148 * Definitions for Deflate. 149 */ 150 151 #define CI_DEFLATE 26 /* config option for Deflate */ 152 #define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */ 153 #define CILEN_DEFLATE 4 /* length of its config option */ 154 155 #define DEFLATE_MIN_SIZE 9 156 #define DEFLATE_MAX_SIZE 15 157 #define DEFLATE_METHOD_VAL 8 158 #define DEFLATE_SIZE(x) (((x) >> 4) + 8) 159 #define DEFLATE_METHOD(x) ((x) & 0x0F) 160 #define DEFLATE_MAKE_OPT(w) ((((w) - 8) << 4) + DEFLATE_METHOD_VAL) 161 #define DEFLATE_CHK_SEQUENCE 0 162 163 /* 164 * Definitions for MPPE. 165 */ 166 167 #define CI_MPPE 18 /* config option for MPPE */ 168 #define CILEN_MPPE 6 /* length of config option */ 169 170 /* 171 * Definitions for other, as yet unsupported, compression methods. 172 */ 173 174 #define CI_PREDICTOR_1 1 /* config option for Predictor-1 */ 175 #define CILEN_PREDICTOR_1 2 /* length of its config option */ 176 #define CI_PREDICTOR_2 2 /* config option for Predictor-2 */ 177 #define CILEN_PREDICTOR_2 2 /* length of its config option */ 178 179 #ifdef __KERNEL__ 180 extern int ppp_register_compressor(struct compressor *); 181 extern void ppp_unregister_compressor(struct compressor *); 182 #endif /* __KERNEL__ */ 183 184 #endif /* _NET_PPP_COMP_H */ 185