2 * ppp-comp.h - Definitions for doing PPP packet compression.
4 * Copyright (c) 1984 Paul Mackerras. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
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
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.
22 * 4. Redistributions of any form whatsoever must retain the following
24 * "This product includes software developed by Paul Mackerras
25 * <paulus@samba.org>".
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.
35 * $Id: ppp-comp.h,v 1.10 2002/12/06 09:49:15 paulus Exp $
39 * ==FILEVERSION 20020319==
41 * NOTE TO MAINTAINERS:
42 * If you modify this file at all, please set the above date.
43 * ppp-comp.h is shipped with a PPP distribution as well as with the kernel;
44 * if everyone increases the FILEVERSION number above, then scripts
45 * can do the right thing when deciding whether to install a new ppp-comp.h
46 * file. Don't change the format of that line otherwise, so the
47 * installation script can recognize it.
50 #ifndef _NET_PPP_COMP_H
51 #define _NET_PPP_COMP_H
54 * The following symbols control whether we include code for
55 * various compression methods.
58 #ifndef DO_BSD_COMPRESS
59 #define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */
62 #define DO_DEFLATE 1 /* by default, include Deflate */
64 #define DO_PREDICTOR_1 0
65 #define DO_PREDICTOR_2 0
68 * Structure giving methods for compression/decompression.
72 int compress_proto; /* CCP compression protocol number */
74 /* Allocate space for a compressor (transmit side) */
75 void *(*comp_alloc) (unsigned char *options, int opt_len);
77 /* Free space used by a compressor */
78 void (*comp_free) (void *state);
80 /* Initialize a compressor */
81 int (*comp_init) (void *state, unsigned char *options,
82 int opt_len, int unit, int opthdr, int debug);
84 /* Reset a compressor */
85 void (*comp_reset) (void *state);
87 /* Compress a packet */
88 int (*compress) (void *state, unsigned char *rptr,
89 unsigned char *obuf, int isize, int osize);
91 /* Return compression statistics */
92 void (*comp_stat) (void *state, struct compstat *stats);
94 /* Allocate space for a decompressor (receive side) */
95 void *(*decomp_alloc) (unsigned char *options, int opt_len);
97 /* Free space used by a decompressor */
98 void (*decomp_free) (void *state);
100 /* Initialize a decompressor */
101 int (*decomp_init) (void *state, unsigned char *options,
102 int opt_len, int unit, int opthdr, int mru,
105 /* Reset a decompressor */
106 void (*decomp_reset) (void *state);
108 /* Decompress a packet. */
109 int (*decompress) (void *state, unsigned char *ibuf, int isize,
110 unsigned char *obuf, int osize);
112 /* Update state for an incompressible packet received */
113 void (*incomp) (void *state, unsigned char *ibuf, int icnt);
115 /* Return decompression statistics */
116 void (*decomp_stat) (void *state, struct compstat *stats);
120 * The return value from decompress routine is the length of the
121 * decompressed packet if successful, otherwise DECOMP_ERROR
122 * or DECOMP_FATALERROR if an error occurred.
124 * We need to make this distinction so that we can disable certain
125 * useful functionality, namely sending a CCP reset-request as a result
126 * of an error detected after decompression. This is to avoid infringing
127 * a patent held by Motorola.
128 * Don't you just lurve software patents.
131 #define DECOMP_ERROR -1 /* error detected before decomp. */
132 #define DECOMP_FATALERROR -2 /* error detected after decomp. */
138 #define CCP_CONFREQ 1
139 #define CCP_CONFACK 2
140 #define CCP_TERMREQ 5
141 #define CCP_TERMACK 6
142 #define CCP_RESETREQ 14
143 #define CCP_RESETACK 15
146 * Max # bytes for a CCP option
149 #define CCP_MAX_OPTION_LENGTH 32
152 * Parts of a CCP packet.
155 #define CCP_CODE(dp) ((dp)[0])
156 #define CCP_ID(dp) ((dp)[1])
157 #define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3])
160 #define CCP_OPT_CODE(dp) ((dp)[0])
161 #define CCP_OPT_LENGTH(dp) ((dp)[1])
162 #define CCP_OPT_MINLEN 2
165 * Definitions for BSD-Compress.
168 #define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */
169 #define CILEN_BSD_COMPRESS 3 /* length of config. option */
171 /* Macros for handling the 3rd byte of the BSD-Compress config option. */
172 #define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */
173 #define BSD_VERSION(x) ((x) >> 5) /* version of option format */
174 #define BSD_CURRENT_VERSION 1 /* current version number */
175 #define BSD_MAKE_OPT(v, n) (((v) << 5) | (n))
177 #define BSD_MIN_BITS 9 /* smallest code size supported */
178 #define BSD_MAX_BITS 15 /* largest code size supported */
181 * Definitions for Deflate.
184 #define CI_DEFLATE 26 /* config option for Deflate */
185 #define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */
186 #define CILEN_DEFLATE 4 /* length of its config option */
188 #define DEFLATE_MIN_SIZE 8
189 #define DEFLATE_MAX_SIZE 15
190 #define DEFLATE_METHOD_VAL 8
191 #define DEFLATE_SIZE(x) (((x) >> 4) + DEFLATE_MIN_SIZE)
192 #define DEFLATE_METHOD(x) ((x) & 0x0F)
193 #define DEFLATE_MAKE_OPT(w) ((((w) - DEFLATE_MIN_SIZE) << 4) \
194 + DEFLATE_METHOD_VAL)
195 #define DEFLATE_CHK_SEQUENCE 0
198 * Definitions for MPPE.
201 #define CI_MPPE 18 /* config option for MPPE */
202 #define CILEN_MPPE 6 /* length of config option */
205 * Definitions for other, as yet unsupported, compression methods.
208 #define CI_PREDICTOR_1 1 /* config option for Predictor-1 */
209 #define CILEN_PREDICTOR_1 2 /* length of its config option */
210 #define CI_PREDICTOR_2 2 /* config option for Predictor-2 */
211 #define CILEN_PREDICTOR_2 2 /* length of its config option */
213 #endif /* _NET_PPP_COMP_H */