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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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070026 */
27
28/*
29 * ==FILEVERSION 980319==
30 *
31 * NOTE TO MAINTAINERS:
32 * If you modify this file at all, please set the above date.
33 * ppp-comp.h is shipped with a PPP distribution as well as with the kernel;
34 * if everyone increases the FILEVERSION number above, then scripts
35 * can do the right thing when deciding whether to install a new ppp-comp.h
36 * file. Don't change the format of that line otherwise, so the
37 * installation script can recognize it.
38 */
39
40#ifndef _NET_PPP_COMP_H
41#define _NET_PPP_COMP_H
42
43struct module;
44
45/*
46 * The following symbols control whether we include code for
47 * various compression methods.
48 */
49
50#ifndef DO_BSD_COMPRESS
51#define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */
52#endif
53#ifndef DO_DEFLATE
54#define DO_DEFLATE 1 /* by default, include Deflate */
55#endif
56#define DO_PREDICTOR_1 0
57#define DO_PREDICTOR_2 0
58
59/*
60 * Structure giving methods for compression/decompression.
61 */
62
63struct compressor {
64 int compress_proto; /* CCP compression protocol number */
65
66 /* Allocate space for a compressor (transmit side) */
67 void *(*comp_alloc) (unsigned char *options, int opt_len);
68
69 /* Free space used by a compressor */
70 void (*comp_free) (void *state);
71
72 /* Initialize a compressor */
73 int (*comp_init) (void *state, unsigned char *options,
74 int opt_len, int unit, int opthdr, int debug);
75
76 /* Reset a compressor */
77 void (*comp_reset) (void *state);
78
79 /* Compress a packet */
80 int (*compress) (void *state, unsigned char *rptr,
81 unsigned char *obuf, int isize, int osize);
82
83 /* Return compression statistics */
84 void (*comp_stat) (void *state, struct compstat *stats);
85
86 /* Allocate space for a decompressor (receive side) */
87 void *(*decomp_alloc) (unsigned char *options, int opt_len);
88
89 /* Free space used by a decompressor */
90 void (*decomp_free) (void *state);
91
92 /* Initialize a decompressor */
93 int (*decomp_init) (void *state, unsigned char *options,
94 int opt_len, int unit, int opthdr, int mru,
95 int debug);
96
97 /* Reset a decompressor */
98 void (*decomp_reset) (void *state);
99
100 /* Decompress a packet. */
101 int (*decompress) (void *state, unsigned char *ibuf, int isize,
102 unsigned char *obuf, int osize);
103
104 /* Update state for an incompressible packet received */
105 void (*incomp) (void *state, unsigned char *ibuf, int icnt);
106
107 /* Return decompression statistics */
108 void (*decomp_stat) (void *state, struct compstat *stats);
109
110 /* Used in locking compressor modules */
111 struct module *owner;
Matt Domschb3f9b922005-11-08 09:40:47 -0800112 /* Extra skb space needed by the compressor algorithm */
113 unsigned int comp_extra;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114};
115
116/*
117 * The return value from decompress routine is the length of the
118 * decompressed packet if successful, otherwise DECOMP_ERROR
119 * or DECOMP_FATALERROR if an error occurred.
120 *
121 * We need to make this distinction so that we can disable certain
122 * useful functionality, namely sending a CCP reset-request as a result
123 * of an error detected after decompression. This is to avoid infringing
124 * a patent held by Motorola.
125 * Don't you just lurve software patents.
126 */
127
128#define DECOMP_ERROR -1 /* error detected before decomp. */
129#define DECOMP_FATALERROR -2 /* error detected after decomp. */
130
131/*
132 * CCP codes.
133 */
134
135#define CCP_CONFREQ 1
136#define CCP_CONFACK 2
137#define CCP_TERMREQ 5
138#define CCP_TERMACK 6
139#define CCP_RESETREQ 14
140#define CCP_RESETACK 15
141
142/*
143 * Max # bytes for a CCP option
144 */
145
146#define CCP_MAX_OPTION_LENGTH 32
147
148/*
149 * Parts of a CCP packet.
150 */
151
152#define CCP_CODE(dp) ((dp)[0])
153#define CCP_ID(dp) ((dp)[1])
154#define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3])
155#define CCP_HDRLEN 4
156
157#define CCP_OPT_CODE(dp) ((dp)[0])
158#define CCP_OPT_LENGTH(dp) ((dp)[1])
159#define CCP_OPT_MINLEN 2
160
161/*
162 * Definitions for BSD-Compress.
163 */
164
165#define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */
166#define CILEN_BSD_COMPRESS 3 /* length of config. option */
167
168/* Macros for handling the 3rd byte of the BSD-Compress config option. */
169#define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */
170#define BSD_VERSION(x) ((x) >> 5) /* version of option format */
171#define BSD_CURRENT_VERSION 1 /* current version number */
172#define BSD_MAKE_OPT(v, n) (((v) << 5) | (n))
173
174#define BSD_MIN_BITS 9 /* smallest code size supported */
175#define BSD_MAX_BITS 15 /* largest code size supported */
176
177/*
178 * Definitions for Deflate.
179 */
180
181#define CI_DEFLATE 26 /* config option for Deflate */
182#define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */
183#define CILEN_DEFLATE 4 /* length of its config option */
184
185#define DEFLATE_MIN_SIZE 9
186#define DEFLATE_MAX_SIZE 15
187#define DEFLATE_METHOD_VAL 8
188#define DEFLATE_SIZE(x) (((x) >> 4) + 8)
189#define DEFLATE_METHOD(x) ((x) & 0x0F)
190#define DEFLATE_MAKE_OPT(w) ((((w) - 8) << 4) + DEFLATE_METHOD_VAL)
191#define DEFLATE_CHK_SEQUENCE 0
192
193/*
Matt Domschb3f9b922005-11-08 09:40:47 -0800194 * Definitions for MPPE.
195 */
196
197#define CI_MPPE 18 /* config option for MPPE */
198#define CILEN_MPPE 6 /* length of config option */
199
200/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 * Definitions for other, as yet unsupported, compression methods.
202 */
203
204#define CI_PREDICTOR_1 1 /* config option for Predictor-1 */
205#define CILEN_PREDICTOR_1 2 /* length of its config option */
206#define CI_PREDICTOR_2 2 /* config option for Predictor-2 */
207#define CILEN_PREDICTOR_2 2 /* length of its config option */
208
209#ifdef __KERNEL__
210extern int ppp_register_compressor(struct compressor *);
211extern void ppp_unregister_compressor(struct compressor *);
212#endif /* __KERNEL__ */
213
214#endif /* _NET_PPP_COMP_H */