1/*
2 * ppp-comp.h - Definitions for doing PPP packet compression.
3 *
4 * Copyright (c) 1994 Paul Mackerras. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in
15 *    the documentation and/or other materials provided with the
16 *    distribution.
17 *
18 * 3. The name(s) of the authors of this software must not be used to
19 *    endorse or promote products derived from this software without
20 *    prior written permission.
21 *
22 * 4. Redistributions of any form whatsoever must retain the following
23 *    acknowledgment:
24 *    "This product includes software developed by Paul Mackerras
25 *     <paulus@samba.org>".
26 *
27 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
28 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
29 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
30 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
31 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
32 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
33 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
34 *
35 * $Id: ppp-comp.h,v 1.2 2002/12/06 09:49:16 paulus Exp $
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 * Structure giving methods for compression/decompression.
56 */
57struct compressor {
58	int	compress_proto;	/* CCP compression protocol number */
59
60	/* Allocate space for a decompressor (receive side) */
61	void	*(*decomp_alloc) __P((u_char *options, int opt_len));
62	/* Free space used by a decompressor */
63	void	(*decomp_free) __P((void *state));
64	/* Initialize a decompressor */
65	int	(*decomp_init) __P((void *state, u_char *options, int opt_len,
66				    int unit, int hdrlen, int mru, int debug));
67	/* Reset a decompressor */
68	void	(*decomp_reset) __P((void *state));
69	/* Decompress a packet. */
70	int	(*decompress) __P((void *state, u_char *mp, int inlen,
71				   u_char *dmp, int *outlen));
72	/* Update state for an incompressible packet received */
73	void	(*incomp) __P((void *state, u_char *mp, int len));
74	/* Return decompression statistics */
75	void	(*decomp_stat) __P((void *state, struct compstat *stats));
76};
77
78/*
79 * Return values for decompress routine.
80 * We need to make these distinctions so that we can disable certain
81 * useful functionality, namely sending a CCP reset-request as a result
82 * of an error detected after decompression.  This is to avoid infringing
83 * a patent held by Motorola.
84 * Don't you just lurve software patents.
85 */
86#define DECOMP_OK		0	/* everything went OK */
87#define DECOMP_ERROR		1	/* error detected before decomp. */
88#define DECOMP_FATALERROR	2	/* error detected after decomp. */
89
90/*
91 * CCP codes.
92 */
93#define CCP_CONFREQ	1
94#define CCP_CONFACK	2
95#define CCP_CONFNAK	3
96#define CCP_CONFREJ	4
97#define CCP_TERMREQ	5
98#define CCP_TERMACK	6
99#define CCP_RESETREQ	14
100#define CCP_RESETACK	15
101
102/*
103 * Max # bytes for a CCP option
104 */
105#define CCP_MAX_OPTION_LENGTH	32
106
107/*
108 * Parts of a CCP packet.
109 */
110#define CCP_CODE(dp)		((dp)[0])
111#define CCP_ID(dp)		((dp)[1])
112#define CCP_LENGTH(dp)		(((dp)[2] << 8) + (dp)[3])
113#define CCP_HDRLEN		4
114
115#define CCP_OPT_CODE(dp)	((dp)[0])
116#define CCP_OPT_LENGTH(dp)	((dp)[1])
117#define CCP_OPT_MINLEN		2
118
119/*
120 * Definitions for BSD-Compress.
121 */
122#define CI_BSD_COMPRESS		21	/* config. option for BSD-Compress */
123#define CILEN_BSD_COMPRESS	3	/* length of config. option */
124
125/* Macros for handling the 3rd byte of the BSD-Compress config option. */
126#define BSD_NBITS(x)		((x) & 0x1F)	/* number of bits requested */
127#define BSD_VERSION(x)		((x) >> 5)	/* version of option format */
128#define BSD_CURRENT_VERSION	1		/* current version number */
129#define BSD_MAKE_OPT(v, n)	(((v) << 5) | (n))
130
131#define BSD_MIN_BITS		9	/* smallest code size supported */
132#define BSD_MAX_BITS		15	/* largest code size supported */
133
134/*
135 * Definitions for Deflate.
136 */
137#define CI_DEFLATE		26	/* config option for Deflate */
138#define CI_DEFLATE_DRAFT	24	/* value used in original draft RFC */
139#define CILEN_DEFLATE		4	/* length of its config option */
140
141#define DEFLATE_MIN_SIZE	8
142#define DEFLATE_MAX_SIZE	15
143#define DEFLATE_METHOD_VAL	8
144#define DEFLATE_SIZE(x)		(((x) >> 4) + DEFLATE_MIN_SIZE)
145#define DEFLATE_METHOD(x)	((x) & 0x0F)
146#define DEFLATE_MAKE_OPT(w)	((((w) - DEFLATE_MIN_SIZE) << 4) \
147				 + DEFLATE_METHOD_VAL)
148#define DEFLATE_CHK_SEQUENCE	0
149
150/*
151 * Definitions for other, as yet unsupported, compression methods.
152 */
153#define CI_PREDICTOR_1		1	/* config option for Predictor-1 */
154#define CILEN_PREDICTOR_1	2	/* length of its config option */
155#define CI_PREDICTOR_2		2	/* config option for Predictor-2 */
156#define CILEN_PREDICTOR_2	2	/* length of its config option */
157
158#endif /* _NET_PPP_COMP_H */
159