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/*

 * ppp-comp.h - Definitions for doing PPP packet compression.

 *

 * Copyright 1994-1998 Paul Mackerras.

 *

 *  This program is free software; you can redistribute it and/or

 *  modify it under the terms of the GNU General Public License

 *  version 2 as published by the Free Software Foundation.

 */

#ifndef _NET_PPP_COMP_H

#define _NET_PPP_COMP_H

/*

 * 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        9

#define DEFLATE_MAX_SIZE        15

#define DEFLATE_METHOD_VAL      8

#define DEFLATE_SIZE(x)         (((x) >> 4) + 8)

#define DEFLATE_METHOD(x)       ((x) & 0x0F)

#define DEFLATE_MAKE_OPT(w)     ((((w) - 8) << 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 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 */