xref: /openbsd/sys/net/ppp-comp.h (revision 952c3118)
1 /*	$OpenBSD: ppp-comp.h,v 1.8 2002/09/13 00:12:07 deraadt Exp $	*/
2 
3 /*
4  * ppp-comp.h - Definitions for doing PPP packet compression.
5  *
6  * Copyright (c) 1989-2002 Paul Mackerras. All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  *
20  * 3. The name(s) of the authors of this software must not be used to
21  *    endorse or promote products derived from this software without
22  *    prior written permission.
23  *
24  * 4. Redistributions of any form whatsoever must retain the following
25  *    acknowledgment:
26  *    "This product includes software developed by Paul Mackerras
27  *     <paulus@samba.org>".
28  *
29  * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
30  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
31  * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
32  * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
33  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
34  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
35  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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  */
57 #ifdef PACKETPTR
58 struct compressor {
59 	int	compress_proto;	/* CCP compression protocol number */
60 
61 	/* Allocate space for a compressor (transmit side) */
62 	void	*(*comp_alloc)(u_char *options, int opt_len);
63 	/* Free space used by a compressor */
64 	void	(*comp_free)(void *state);
65 	/* Initialize a compressor */
66 	int	(*comp_init)(void *state, u_char *options, int opt_len,
67 				  int unit, int hdrlen, int debug);
68 	/* Reset a compressor */
69 	void	(*comp_reset)(void *state);
70 	/* Compress a packet */
71 	int	(*compress)(void *state, PACKETPTR *mret,
72 				 PACKETPTR mp, int orig_len, int max_len);
73 	/* Return compression statistics */
74 	void	(*comp_stat)(void *state, struct compstat *stats);
75 
76 	/* Allocate space for a decompressor (receive side) */
77 	void	*(*decomp_alloc)(u_char *options, int opt_len);
78 	/* Free space used by a decompressor */
79 	void	(*decomp_free)(void *state);
80 	/* Initialize a decompressor */
81 	int	(*decomp_init)(void *state, u_char *options, int opt_len,
82 				    int unit, int hdrlen, int mru, int debug);
83 	/* Reset a decompressor */
84 	void	(*decomp_reset)(void *state);
85 	/* Decompress a packet. */
86 	int	(*decompress)(void *state, PACKETPTR mp,
87 				   PACKETPTR *dmpp);
88 	/* Update state for an incompressible packet received */
89 	void	(*incomp)(void *state, PACKETPTR mp);
90 	/* Return decompression statistics */
91 	void	(*decomp_stat)(void *state, struct compstat *stats);
92 };
93 #endif /* PACKETPTR */
94 
95 /*
96  * Return values for decompress routine.
97  * We need to make these distinctions so that we can disable certain
98  * useful functionality, namely sending a CCP reset-request as a result
99  * of an error detected after decompression.  This is to avoid infringing
100  * a patent held by Motorola.
101  * Don't you just lurve software patents.
102  */
103 #define DECOMP_OK		0	/* everything went OK */
104 #define DECOMP_ERROR		1	/* error detected before decomp. */
105 #define DECOMP_FATALERROR	2	/* error detected after decomp. */
106 
107 /*
108  * CCP codes.
109  */
110 #define CCP_CONFREQ	1
111 #define CCP_CONFACK	2
112 #define CCP_TERMREQ	5
113 #define CCP_TERMACK	6
114 #define CCP_RESETREQ	14
115 #define CCP_RESETACK	15
116 
117 /*
118  * Max # bytes for a CCP option
119  */
120 #define CCP_MAX_OPTION_LENGTH	32
121 
122 /*
123  * Parts of a CCP packet.
124  */
125 #define CCP_CODE(dp)		((dp)[0])
126 #define CCP_ID(dp)		((dp)[1])
127 #define CCP_LENGTH(dp)		(((dp)[2] << 8) + (dp)[3])
128 #define CCP_HDRLEN		4
129 
130 #define CCP_OPT_CODE(dp)	((dp)[0])
131 #define CCP_OPT_LENGTH(dp)	((dp)[1])
132 #define CCP_OPT_MINLEN		2
133 
134 /*
135  * Definitions for BSD-Compress.
136  */
137 #define CI_BSD_COMPRESS		21	/* config. option for BSD-Compress */
138 #define CILEN_BSD_COMPRESS	3	/* length of config. option */
139 
140 /* Macros for handling the 3rd byte of the BSD-Compress config option. */
141 #define BSD_NBITS(x)		((x) & 0x1F)	/* number of bits requested */
142 #define BSD_VERSION(x)		((x) >> 5)	/* version of option format */
143 #define BSD_CURRENT_VERSION	1		/* current version number */
144 #define BSD_MAKE_OPT(v, n)	(((v) << 5) | (n))
145 
146 #define BSD_MIN_BITS		9	/* smallest code size supported */
147 #define BSD_MAX_BITS		15	/* largest code size supported */
148 
149 /*
150  * Definitions for Deflate.
151  */
152 #define CI_DEFLATE		26	/* config option for Deflate */
153 #define CI_DEFLATE_DRAFT	24	/* value used in original draft RFC */
154 #define CILEN_DEFLATE		4	/* length of its config option */
155 
156 #define DEFLATE_MIN_SIZE	8
157 #define DEFLATE_MAX_SIZE	15
158 #define DEFLATE_METHOD_VAL	8
159 #define DEFLATE_SIZE(x)		(((x) >> 4) + DEFLATE_MIN_SIZE)
160 #define DEFLATE_METHOD(x)	((x) & 0x0F)
161 #define DEFLATE_MAKE_OPT(w)	((((w) - DEFLATE_MIN_SIZE) << 4) \
162 				 + DEFLATE_METHOD_VAL)
163 #define DEFLATE_CHK_SEQUENCE	0
164 
165 /*
166  * Definitions for other, as yet unsupported, compression methods.
167  */
168 #define CI_PREDICTOR_1		1	/* config option for Predictor-1 */
169 #define CILEN_PREDICTOR_1	2	/* length of its config option */
170 #define CI_PREDICTOR_2		2	/* config option for Predictor-2 */
171 #define CILEN_PREDICTOR_2	2	/* length of its config option */
172 
173 #endif /* _NET_PPP_COMP_H_ */
174