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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * ppp-comp.h - Definitions for doing PPP packet compression.
3 *
4 * Copyright (c) 1994 The Australian National University.
5 * All rights reserved.
6 *
7 * Permission to use, copy, modify, and distribute this software and its
8 * documentation is hereby granted, provided that the above copyright
9 * notice appears in all copies. This software is provided without any
10 * warranty, express or implied. The Australian National University
11 * makes no representations about the suitability of this software for
12 * any purpose.
13 *
14 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
15 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
16 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
17 * THE AUSTRALIAN NATIONAL UNIVERSITY HAVE BEEN ADVISED OF THE POSSIBILITY
18 * OF SUCH DAMAGE.
19 *
20 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
21 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
22 * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
23 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
24 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
25 * OR MODIFICATIONS.
26 *
27 * $Id: ppp-comp.h,v 1.6 1997/11/27 06:04:44 paulus Exp $
28 */
29
30/*
31 * ==FILEVERSION 980319==
32 *
33 * NOTE TO MAINTAINERS:
34 * If you modify this file at all, please set the above date.
35 * ppp-comp.h is shipped with a PPP distribution as well as with the kernel;
36 * if everyone increases the FILEVERSION number above, then scripts
37 * can do the right thing when deciding whether to install a new ppp-comp.h
38 * file. Don't change the format of that line otherwise, so the
39 * installation script can recognize it.
40 */
41
42#ifndef _NET_PPP_COMP_H
43#define _NET_PPP_COMP_H
44
45struct module;
46
47/*
48 * The following symbols control whether we include code for
49 * various compression methods.
50 */
51
52#ifndef DO_BSD_COMPRESS
53#define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */
54#endif
55#ifndef DO_DEFLATE
56#define DO_DEFLATE 1 /* by default, include Deflate */
57#endif
58#define DO_PREDICTOR_1 0
59#define DO_PREDICTOR_2 0
60
61/*
62 * Structure giving methods for compression/decompression.
63 */
64
65struct compressor {
66 int compress_proto; /* CCP compression protocol number */
67
68 /* Allocate space for a compressor (transmit side) */
69 void *(*comp_alloc) (unsigned char *options, int opt_len);
70
71 /* Free space used by a compressor */
72 void (*comp_free) (void *state);
73
74 /* Initialize a compressor */
75 int (*comp_init) (void *state, unsigned char *options,
76 int opt_len, int unit, int opthdr, int debug);
77
78 /* Reset a compressor */
79 void (*comp_reset) (void *state);
80
81 /* Compress a packet */
82 int (*compress) (void *state, unsigned char *rptr,
83 unsigned char *obuf, int isize, int osize);
84
85 /* Return compression statistics */
86 void (*comp_stat) (void *state, struct compstat *stats);
87
88 /* Allocate space for a decompressor (receive side) */
89 void *(*decomp_alloc) (unsigned char *options, int opt_len);
90
91 /* Free space used by a decompressor */
92 void (*decomp_free) (void *state);
93
94 /* Initialize a decompressor */
95 int (*decomp_init) (void *state, unsigned char *options,
96 int opt_len, int unit, int opthdr, int mru,
97 int debug);
98
99 /* Reset a decompressor */
100 void (*decomp_reset) (void *state);
101
102 /* Decompress a packet. */
103 int (*decompress) (void *state, unsigned char *ibuf, int isize,
104 unsigned char *obuf, int osize);
105
106 /* Update state for an incompressible packet received */
107 void (*incomp) (void *state, unsigned char *ibuf, int icnt);
108
109 /* Return decompression statistics */
110 void (*decomp_stat) (void *state, struct compstat *stats);
111
112 /* Used in locking compressor modules */
113 struct module *owner;
Matt Domschb3f9b922005-11-08 09:40:47 -0800114 /* Extra skb space needed by the compressor algorithm */
115 unsigned int comp_extra;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116};
117
118/*
119 * The return value from decompress routine is the length of the
120 * decompressed packet if successful, otherwise DECOMP_ERROR
121 * or DECOMP_FATALERROR if an error occurred.
122 *
123 * We need to make this distinction so that we can disable certain
124 * useful functionality, namely sending a CCP reset-request as a result
125 * of an error detected after decompression. This is to avoid infringing
126 * a patent held by Motorola.
127 * Don't you just lurve software patents.
128 */
129
130#define DECOMP_ERROR -1 /* error detected before decomp. */
131#define DECOMP_FATALERROR -2 /* error detected after decomp. */
132
133/*
134 * CCP codes.
135 */
136
137#define CCP_CONFREQ 1
138#define CCP_CONFACK 2
139#define CCP_TERMREQ 5
140#define CCP_TERMACK 6
141#define CCP_RESETREQ 14
142#define CCP_RESETACK 15
143
144/*
145 * Max # bytes for a CCP option
146 */
147
148#define CCP_MAX_OPTION_LENGTH 32
149
150/*
151 * Parts of a CCP packet.
152 */
153
154#define CCP_CODE(dp) ((dp)[0])
155#define CCP_ID(dp) ((dp)[1])
156#define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3])
157#define CCP_HDRLEN 4
158
159#define CCP_OPT_CODE(dp) ((dp)[0])
160#define CCP_OPT_LENGTH(dp) ((dp)[1])
161#define CCP_OPT_MINLEN 2
162
163/*
164 * Definitions for BSD-Compress.
165 */
166
167#define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */
168#define CILEN_BSD_COMPRESS 3 /* length of config. option */
169
170/* Macros for handling the 3rd byte of the BSD-Compress config option. */
171#define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */
172#define BSD_VERSION(x) ((x) >> 5) /* version of option format */
173#define BSD_CURRENT_VERSION 1 /* current version number */
174#define BSD_MAKE_OPT(v, n) (((v) << 5) | (n))
175
176#define BSD_MIN_BITS 9 /* smallest code size supported */
177#define BSD_MAX_BITS 15 /* largest code size supported */
178
179/*
180 * Definitions for Deflate.
181 */
182
183#define CI_DEFLATE 26 /* config option for Deflate */
184#define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */
185#define CILEN_DEFLATE 4 /* length of its config option */
186
187#define DEFLATE_MIN_SIZE 9
188#define DEFLATE_MAX_SIZE 15
189#define DEFLATE_METHOD_VAL 8
190#define DEFLATE_SIZE(x) (((x) >> 4) + 8)
191#define DEFLATE_METHOD(x) ((x) & 0x0F)
192#define DEFLATE_MAKE_OPT(w) ((((w) - 8) << 4) + DEFLATE_METHOD_VAL)
193#define DEFLATE_CHK_SEQUENCE 0
194
195/*
Matt Domschb3f9b922005-11-08 09:40:47 -0800196 * Definitions for MPPE.
197 */
198
199#define CI_MPPE 18 /* config option for MPPE */
200#define CILEN_MPPE 6 /* length of config option */
201
202/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 * Definitions for other, as yet unsupported, compression methods.
204 */
205
206#define CI_PREDICTOR_1 1 /* config option for Predictor-1 */
207#define CILEN_PREDICTOR_1 2 /* length of its config option */
208#define CI_PREDICTOR_2 2 /* config option for Predictor-2 */
209#define CILEN_PREDICTOR_2 2 /* length of its config option */
210
211#ifdef __KERNEL__
212extern int ppp_register_compressor(struct compressor *);
213extern void ppp_unregister_compressor(struct compressor *);
214#endif /* __KERNEL__ */
215
216#endif /* _NET_PPP_COMP_H */