FreeBSD/Linux Kernel Cross Reference
sys/net/ppp_comp.h

     /*
      * ppp_comp.h - Definitions for doing PPP packet compression.
      *
      * Copyright (c) 1994 The Australian National University.
      * All rights reserved.
      *
      * Permission to use, copy, modify, and distribute this software and its
      * documentation is hereby granted, provided that the above copyright
      * notice appears in all copies.  This software is provided without any
     * warranty, express or implied. The Australian National University
     * makes no representations about the suitability of this software for
     * any purpose.
     *
     * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
     * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
     * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
     * THE AUSTRALIAN NATIONAL UNIVERSITY HAVE BEEN ADVISED OF THE POSSIBILITY
     * OF SUCH DAMAGE.
     *
     * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
     * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
     * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
     * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
     * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
     * OR MODIFICATIONS.
     *
     * $FreeBSD: releng/5.0/sys/net/ppp_comp.h 93084 2002-03-24 09:34:04Z bde $
     */
    
    #ifndef _NET_PPP_COMP_H
    #define _NET_PPP_COMP_H
    
    /*
     * Structure giving methods for compression/decompression.
     */
    #ifdef PACKETPTR
    struct compressor {
            int     compress_proto; /* CCP compression protocol number */
    
            /* Allocate space for a compressor (transmit side) */
            void    *(*comp_alloc)(u_char *options, int opt_len);
            /* Free space used by a compressor */
            void    (*comp_free)(void *state);
            /* Initialize a compressor */
            int     (*comp_init)(void *state, u_char *options, int opt_len,
                        int unit, int hdrlen, int debug);
            /* Reset a compressor */
            void    (*comp_reset)(void *state);
            /* Compress a packet */
            int     (*compress)(void *state, PACKETPTR *mret, PACKETPTR mp,
                        int orig_len, int max_len);
            /* Return compression statistics */
            void    (*comp_stat)(void *state, struct compstat *stats);
    
            /* Allocate space for a decompressor (receive side) */
            void    *(*decomp_alloc)(u_char *options, int opt_len);
            /* Free space used by a decompressor */
            void    (*decomp_free)(void *state);
            /* Initialize a decompressor */
            int     (*decomp_init)(void *state, u_char *options, int opt_len,
                        int unit, int hdrlen, int mru, int debug);
            /* Reset a decompressor */
            void    (*decomp_reset)(void *state);
            /* Decompress a packet. */
            int     (*decompress)(void *state, PACKETPTR mp, PACKETPTR *dmpp);
            /* Update state for an incompressible packet received */
            void    (*incomp)(void *state, PACKETPTR mp);
            /* Return decompression statistics */
            void    (*decomp_stat)(void *state, struct compstat *stats);
    };
    #endif /* PACKETPTR */
    
    /*
     * Return values for decompress routine.
     * We need to make these distinctions so that we can disable certain
     * useful functionality, namely sending a CCP reset-request as a result
     * of an error detected after decompression.  This is to avoid infringing
     * a patent held by Motorola.
     * Don't you just lurve software patents.
     */
    #define DECOMP_OK               0       /* everything went OK */
    #define DECOMP_ERROR            1       /* error detected before decomp. */
    #define DECOMP_FATALERROR       2       /* error detected after decomp. */
    
    /*
     * CCP codes.
     */
    #define CCP_CONFREQ     1
    #define CCP_CONFACK     2
    #define CCP_TERMREQ     5
    #define CCP_TERMACK     6
    #define CCP_RESETREQ    14
    #define CCP_RESETACK    15
    
    /*
     * Max # bytes for a CCP option
     */
    #define CCP_MAX_OPTION_LENGTH   32
    
   /*
    * Parts of a CCP packet.
    */
   #define CCP_CODE(dp)            ((dp)[0])
   #define CCP_ID(dp)              ((dp)[1])
   #define CCP_LENGTH(dp)          (((dp)[2] << 8) + (dp)[3])
   #define CCP_HDRLEN              4
   
   #define CCP_OPT_CODE(dp)        ((dp)[0])
   #define CCP_OPT_LENGTH(dp)      ((dp)[1])
   #define CCP_OPT_MINLEN          2
   
   /*
    * Definitions for BSD-Compress.
    */
   #define CI_BSD_COMPRESS         21      /* config. option for BSD-Compress */
   #define CILEN_BSD_COMPRESS      3       /* length of config. option */
   
   /* Macros for handling the 3rd byte of the BSD-Compress config option. */
   #define BSD_NBITS(x)            ((x) & 0x1F)    /* number of bits requested */
   #define BSD_VERSION(x)          ((x) >> 5)      /* version of option format */
   #define BSD_CURRENT_VERSION     1               /* current version number */
   #define BSD_MAKE_OPT(v, n)      (((v) << 5) | (n))
   
   #define BSD_MIN_BITS            9       /* smallest code size supported */
   #define BSD_MAX_BITS            15      /* largest code size supported */
   
   /*
    * Definitions for Deflate.
    */
   #define CI_DEFLATE              26      /* config option for Deflate */
   #define CI_DEFLATE_DRAFT        24      /* value used in original draft RFC */
   #define CILEN_DEFLATE           4       /* length of its config option */
   
   #define DEFLATE_MIN_SIZE        8
   #define DEFLATE_MAX_SIZE        15
   #define DEFLATE_METHOD_VAL      8
   #define DEFLATE_SIZE(x)         (((x) >> 4) + DEFLATE_MIN_SIZE)
   #define DEFLATE_METHOD(x)       ((x) & 0x0F)
   #define DEFLATE_MAKE_OPT(w)     ((((w) - DEFLATE_MIN_SIZE) << 4) \
                                    + DEFLATE_METHOD_VAL)
   #define DEFLATE_CHK_SEQUENCE    0
   
   /*
    * Definitions for other, as yet unsupported, compression methods.
    */
   #define CI_PREDICTOR_1          1       /* config option for Predictor-1 */
   #define CILEN_PREDICTOR_1       2       /* length of its config option */
   #define CI_PREDICTOR_2          2       /* config option for Predictor-2 */
   #define CILEN_PREDICTOR_2       2       /* length of its config option */
   
   #endif /* _NET_PPP_COMP_H */

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