sys/net/ppp-comp.h

   1 /*      $NetBSD: ppp-comp.h,v 1.15 2008/11/25 02:40:36 cube Exp $       */
   2
   3 /*
   4  * ppp-comp.h - Definitions for doing PPP packet compression.
   5  *
   6  * Copyright (c) 1989-2002 Paul Mackerras. All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. The name(s) of the authors of this software must not be used to
  21  *    endorse or promote products derived from this software without
  22  *    prior written permission.
  23  *
  24  * 4. Redistributions of any form whatsoever must retain the following
  25  *    acknowledgment:
  26  *    "This product includes software developed by Paul Mackerras
  27  *     <paulus@samba.org>".
  28  *
  29  * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
  30  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  31  * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
  32  * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  33  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
  34  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  35  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  36  */
  37
  38 #ifndef _NET_PPP_COMP_H_
  39 #define _NET_PPP_COMP_H_
  40
  41 /*
  42  * The following symbols control whether we include code for
  43  * various compression methods.
  44  */
  45 #ifndef DO_BSD_COMPRESS
  46 #define DO_BSD_COMPRESS 1       /* by default, include BSD-Compress */
  47 #endif
  48 #ifndef DO_DEFLATE
  49 #define DO_DEFLATE      1       /* by default, include Deflate */
  50 #endif
  51 #define DO_PREDICTOR_1  0
  52 #define DO_PREDICTOR_2  0
  53
  54 /*
  55  * How many entries to make available in the compressors table
  56  */
  57 #ifndef PPP_COMPRESSORS_MAX
  58 #define PPP_COMPRESSORS_MAX     8
  59 #endif
  60
  61 /*
  62  * Structure giving methods for compression/decompression.
  63  */
  64 #ifdef PACKETPTR
  65 #include <sys/queue.h>
  66
  67 struct compressor {
  68         int     compress_proto; /* CCP compression protocol number */
  69
  70         /* Allocate space for a compressor (transmit side) */
  71         void    *(*comp_alloc)(u_char *, int);
  72         /* Free space used by a compressor */
  73         void    (*comp_free)(void *);
  74         /* Initialize a compressor */
  75         int     (*comp_init)(void *, u_char *, int, int, int, int);
  76         /* Reset a compressor */
  77         void    (*comp_reset)(void *);
  78         /* Compress a packet */
  79         int     (*compress)(void *, PACKETPTR *, PACKETPTR, int, int);
  80         /* Return compression statistics */
  81         void    (*comp_stat)(void *, struct compstat *);
  82
  83         /* Allocate space for a decompressor (receive side) */
  84         void    *(*decomp_alloc)(u_char *, int);
  85         /* Free space used by a decompressor */
  86         void    (*decomp_free)(void *);
  87         /* Initialize a decompressor */
  88         int     (*decomp_init)(void *, u_char *, int, int, int, int, int);
  89         /* Reset a decompressor */
  90         void    (*decomp_reset)(void *);
  91         /* Decompress a packet. */
  92         int     (*decompress)(void *, PACKETPTR, PACKETPTR *);
  93         /* Update state for an incompressible packet received */
  94         void    (*incomp)(void *, PACKETPTR);
  95         /* Return decompression statistics */
  96         void    (*decomp_stat)(void *, struct compstat *);
  97
  98         LIST_ENTRY(compressor)  comp_list;
  99         unsigned int            comp_refcnt;
 100 };
 101 #endif /* PACKETPTR */
 102
 103 /*
 104  * Return values for decompress routine.
 105  * We need to make these distinctions so that we can disable certain
 106  * useful functionality, namely sending a CCP reset-request as a result
 107  * of an error detected after decompression.  This is to avoid infringing
 108  * a patent held by Motorola.
 109  * Don't you just lurve software patents.
 110  */
 111 #define DECOMP_OK               0       /* everything went OK */
 112 #define DECOMP_ERROR            1       /* error detected before decomp. */
 113 #define DECOMP_FATALERROR       2       /* error detected after decomp. */
 114
 115 /*
 116  * CCP codes.
 117  */
 118 #define CCP_CONFREQ     1
 119 #define CCP_CONFACK     2
 120 #define CCP_CONFNAK     3
 121 #define CCP_CONFREJ     4
 122 #define CCP_TERMREQ     5
 123 #define CCP_TERMACK     6
 124 #define CCP_RESETREQ    14
 125 #define CCP_RESETACK    15
 126
 127 /*
 128  * Max # bytes for a CCP option
 129  */
 130 #define CCP_MAX_OPTION_LENGTH   64
 131
 132 /*
 133  * Parts of a CCP packet.
 134  */
 135 #define CCP_CODE(dp)            ((dp)[0])
 136 #define CCP_ID(dp)              ((dp)[1])
 137 #define CCP_LENGTH(dp)          (((dp)[2] << 8) + (dp)[3])
 138 #define CCP_HDRLEN              4
 139
 140 #define CCP_OPT_CODE(dp)        ((dp)[0])
 141 #define CCP_OPT_LENGTH(dp)      ((dp)[1])
 142 #define CCP_OPT_MINLEN          2
 143
 144 /*
 145  * Definitions for BSD-Compress.
 146  */
 147 #define CI_BSD_COMPRESS         21      /* config. option for BSD-Compress */
 148 #define CILEN_BSD_COMPRESS      3       /* length of config. option */
 149
 150 /* Macros for handling the 3rd byte of the BSD-Compress config option. */
 151 #define BSD_NBITS(x)            ((x) & 0x1F)    /* number of bits requested */
 152 #define BSD_VERSION(x)          ((x) >> 5)      /* version of option format */
 153 #define BSD_CURRENT_VERSION     1               /* current version number */
 154 #define BSD_MAKE_OPT(v, n)      (((v) << 5) | (n))
 155
 156 #define BSD_MIN_BITS            9       /* smallest code size supported */
 157 #define BSD_MAX_BITS            15      /* largest code size supported */
 158
 159 /*
 160  * Definitions for Deflate.
 161  */
 162 #define CI_DEFLATE              26      /* config option for Deflate */
 163 #define CI_DEFLATE_DRAFT        24      /* value used in original draft RFC */
 164
 165 #define CILEN_DEFLATE           4       /* length of its config option */
 166
 167 #define DEFLATE_MIN_SIZE        8
 168 #define DEFLATE_MAX_SIZE        15
 169 #define DEFLATE_METHOD_VAL      8
 170 #define DEFLATE_SIZE(x)         (((x) >> 4) + DEFLATE_MIN_SIZE)
 171 #define DEFLATE_METHOD(x)       ((x) & 0x0F)
 172 #define DEFLATE_MAKE_OPT(w)     ((((w) - DEFLATE_MIN_SIZE) << 4) \
 173                                  + DEFLATE_METHOD_VAL)
 174 #define DEFLATE_CHK_SEQUENCE    0
 175
 176 /*
 177  * Definitions for MPPE.
 178  */
 179 #define CI_MPPE                 18      /* config option for MPPE */
 180 #define CILEN_MPPE              6       /* length of config option */
 181
 182 #define MPPE_PAD                4       /* MPPE growth per frame */
 183 #define MPPE_MAX_KEY_LEN        16      /* largest key length (128-bit) */
 184
 185 /* option bits for ccp_options.mppe */
 186 #define MPPE_OPT_40             0x01    /* 40 bit */
 187 #define MPPE_OPT_128            0x02    /* 128 bit */
 188 #define MPPE_OPT_STATEFUL       0x04    /* stateful mode */
 189 /* unsupported opts */
 190 #define MPPE_OPT_56             0x08    /* 56 bit */
 191 #define MPPE_OPT_MPPC           0x10    /* MPPC compression */
 192 #define MPPE_OPT_D              0x20    /* Unknown */
 193 #define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
 194 #define MPPE_OPT_UNKNOWN        0x40    /* Bits !defined in RFC 3078 were set */
 195
 196 /*
 197  * This is not nice ... the alternative is a bitfield struct though.
 198  * And unfortunately, we cannot share the same bits for the option
 199  * names above since C and H are the same bit.  We could do a uint32_t
 200  * but then we have to do a htonl() all the time and/or we still need
 201  * to know which octet is which.
 202  */
 203 #define MPPE_C_BIT              0x01    /* MPPC */
 204 #define MPPE_D_BIT              0x10    /* Obsolete, usage unknown */
 205 #define MPPE_L_BIT              0x20    /* 40-bit */
 206 #define MPPE_S_BIT              0x40    /* 128-bit */
 207 #define MPPE_M_BIT              0x80    /* 56-bit, not supported */
 208 #define MPPE_H_BIT              0x01    /* Stateless (in a different byte) */
 209
 210 /* Does not include H bit; used for least significant octet only. */
 211 #define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
 212
 213 /* Build a CI from mppe opts (see RFC 3078) */
 214 #define MPPE_OPTS_TO_CI(opts, ci)               \
 215     do {                                        \
 216         u_char *ptr = ci; /* u_char[4] */       \
 217                                                 \
 218         /* H bit */                             \
 219         if (opts & MPPE_OPT_STATEFUL)           \
 220             *ptr++ = 0x0;                       \
 221         else                                    \
 222             *ptr++ = MPPE_H_BIT;                \
 223         *ptr++ = 0;                             \
 224         *ptr++ = 0;                             \
 225                                                 \
 226         /* S,L bits */                          \
 227         *ptr = 0;                               \
 228         if (opts & MPPE_OPT_128)                \
 229             *ptr |= MPPE_S_BIT;                 \
 230         if (opts & MPPE_OPT_40)                 \
 231             *ptr |= MPPE_L_BIT;                 \
 232         /* M,D,C bits not supported */          \
 233     } while (/* CONSTCOND */ 0)
 234
 235 /* The reverse of the above */
 236 #define MPPE_CI_TO_OPTS(ci, opts)               \
 237     do {                                        \
 238         u_char *ptr = ci; /* u_char[4] */       \
 239                                                 \
 240         opts = 0;                               \
 241                                                 \
 242         /* H bit */                             \
 243         if (!(ptr[0] & MPPE_H_BIT))             \
 244             opts |= MPPE_OPT_STATEFUL;          \
 245                                                 \
 246         /* S,L bits */                          \
 247         if (ptr[3] & MPPE_S_BIT)                \
 248             opts |= MPPE_OPT_128;               \
 249         if (ptr[3] & MPPE_L_BIT)                \
 250             opts |= MPPE_OPT_40;                \
 251                                                 \
 252         /* M,D,C bits */                        \
 253         if (ptr[3] & MPPE_M_BIT)                \
 254             opts |= MPPE_OPT_56;                \
 255         if (ptr[3] & MPPE_D_BIT)                \
 256             opts |= MPPE_OPT_D;                 \
 257         if (ptr[3] & MPPE_C_BIT)                \
 258             opts |= MPPE_OPT_MPPC;              \
 259                                                 \
 260         /* Other bits */                        \
 261         if (ptr[0] & ~MPPE_H_BIT)               \
 262             opts |= MPPE_OPT_UNKNOWN;           \
 263         if (ptr[1] || ptr[2])                   \
 264             opts |= MPPE_OPT_UNKNOWN;           \
 265         if (ptr[3] & ~MPPE_ALL_BITS)            \
 266             opts |= MPPE_OPT_UNKNOWN;           \
 267     } while (/* CONSTCOND */ 0)
 268
 269 /*
 270  * Definitions for other, as yet unsupported, compression methods.
 271  */
 272 #define CI_PREDICTOR_1          1       /* config option for Predictor-1 */
 273 #define CILEN_PREDICTOR_1       2       /* length of its config option */
 274 #define CI_PREDICTOR_2          2       /* config option for Predictor-2 */
 275 #define CILEN_PREDICTOR_2       2       /* length of its config option */
 276
 277 #endif /* !_NET_PPP_COMP_H_ */