[mirror_ubuntu-bionic-kernel.git] / include / linux / ppp-comp.h

/*
 * 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

struct module;

/*
 * 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.
 */

struct compressor {
	int	compress_proto;	/* CCP compression protocol number */

	/* Allocate space for a compressor (transmit side) */
	void	*(*comp_alloc) (unsigned char *options, int opt_len);

	/* Free space used by a compressor */
	void	(*comp_free) (void *state);

	/* Initialize a compressor */
	int	(*comp_init) (void *state, unsigned char *options,
			      int opt_len, int unit, int opthdr, int debug);

	/* Reset a compressor */
	void	(*comp_reset) (void *state);

	/* Compress a packet */
	int     (*compress) (void *state, unsigned char *rptr,
			      unsigned char *obuf, int isize, int osize);

	/* Return compression statistics */
	void	(*comp_stat) (void *state, struct compstat *stats);

	/* Allocate space for a decompressor (receive side) */
	void	*(*decomp_alloc) (unsigned char *options, int opt_len);

	/* Free space used by a decompressor */
	void	(*decomp_free) (void *state);

	/* Initialize a decompressor */
	int	(*decomp_init) (void *state, unsigned char *options,
				int opt_len, int unit, int opthdr, int mru,
				int debug);

	/* Reset a decompressor */
	void	(*decomp_reset) (void *state);

	/* Decompress a packet. */
	int	(*decompress) (void *state, unsigned char *ibuf, int isize,
				unsigned char *obuf, int osize);

	/* Update state for an incompressible packet received */
	void	(*incomp) (void *state, unsigned char *ibuf, int icnt);

	/* Return decompression statistics */
	void	(*decomp_stat) (void *state, struct compstat *stats);

	/* Used in locking compressor modules */
	struct module *owner;
	/* Extra skb space needed by the compressor algorithm */
	unsigned int comp_extra;
};

/*
 * The return value from decompress routine is the length of the
 * decompressed packet if successful, otherwise DECOMP_ERROR
 * or DECOMP_FATALERROR if an error occurred.
 * 
 * We need to make this distinction 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_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	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 */

#ifdef __KERNEL__
extern int ppp_register_compressor(struct compressor *);
extern void ppp_unregister_compressor(struct compressor *);
#endif /* __KERNEL__ */

#endif /* _NET_PPP_COMP_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* ppp-comp.h - Definitions for doing PPP packet compression.
	3	*
784db3f0	4	* Copyright 1994-1998 Paul Mackerras.
1da177e4	5	*
784db3f0 PM	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.
1da177e4	9	*/
1da177e4 LT	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;
b3f9b92a MD	82	/* Extra skb space needed by the compressor algorithm */
b3f9b92a MD	83	unsigned int comp_extra;
1da177e4 LT	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
b3f9b92a MD	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
1da177e4 LT	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 */