text: /*
   * 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.
   *
   * $Id: ppp-comp.h,v 1.1.1.1 1999/11/22 03:47:53 christ Exp $
   */
  
  #ifndef _NET_PPP_COMP_H
  #define _NET_PPP_COMP_H
  
  /*
   * The following symbols control whether we include code for
   * various compression methods.
   */
  #ifndef DO_BSD_COMPRESS
  #define DO_BSD_COMPRESS	1	/* by default, include BSD-Compress */
  #endif
  #ifndef DO_DEFLATE
  #define DO_DEFLATE	1	/* by default, include Deflate */
  #endif
  #define DO_PREDICTOR_1	0
  #define DO_PREDICTOR_2	0
  
  /*
   * 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) __P((u_char *options, int opt_len));
  	/* Free space used by a compressor */
  	void	(*comp_free) __P((void *state));
  	/* Initialize a compressor */
  	int	(*comp_init) __P((void *state, u_char *options, int opt_len,
  				  int unit, int hdrlen, int debug));
  	/* Reset a compressor */
  	void	(*comp_reset) __P((void *state));
  	/* Compress a packet */
  	int	(*compress) __P((void *state, PACKETPTR *mret,
  				 PACKETPTR mp, int orig_len, int max_len));
  	/* Return compression statistics */
  	void	(*comp_stat) __P((void *state, struct compstat *stats));
  
  	/* Allocate space for a decompressor (receive side) */
  	void	*(*decomp_alloc) __P((u_char *options, int opt_len));
  	/* Free space used by a decompressor */
  	void	(*decomp_free) __P((void *state));
  	/* Initialize a decompressor */
  	int	(*decomp_init) __P((void *state, u_char *options, int opt_len,
  				    int unit, int hdrlen, int mru, int debug));
  	/* Reset a decompressor */
  	void	(*decomp_reset) __P((void *state));
  	/* Decompress a packet. */
  	int	(*decompress) __P((void *state, PACKETPTR mp,
  				   PACKETPTR *dmpp));
  	/* Update state for an incompressible packet received */
  	void	(*incomp) __P((void *state, PACKETPTR mp));
  	/* Return decompression statistics */
  	void	(*decomp_stat) __P((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	64
  
  /*
   * 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 MPPE.
   */
  
  #define CI_MPPE			18	/* config. option for MPPE */
  #define CILEN_MPPE		6	/* length of config. option */
  
  /*
   * Definitions for Stac LZS.
   */
  
  #define CI_LZS			17	/* config option for Stac LZS */
  #define CILEN_LZS		5	/* length of config option */
  
  /*
   * 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 */
  