2 * ppp-comp.h - Definitions for doing PPP packet compression.
4 * Copyright (c) 1994 The Australian National University.
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
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
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,
29 * ==FILEVERSION 980319==
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.
40 #ifndef _NET_PPP_COMP_H
41 #define _NET_PPP_COMP_H
46 * The following symbols control whether we include code for
47 * various compression methods.
50 #ifndef DO_BSD_COMPRESS
51 #define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */
54 #define DO_DEFLATE 1 /* by default, include Deflate */
56 #define DO_PREDICTOR_1 0
57 #define DO_PREDICTOR_2 0
60 * Structure giving methods for compression/decompression.
64 int compress_proto
; /* CCP compression protocol number */
66 /* Allocate space for a compressor (transmit side) */
67 void *(*comp_alloc
) (unsigned char *options
, int opt_len
);
69 /* Free space used by a compressor */
70 void (*comp_free
) (void *state
);
72 /* Initialize a compressor */
73 int (*comp_init
) (void *state
, unsigned char *options
,
74 int opt_len
, int unit
, int opthdr
, int debug
);
76 /* Reset a compressor */
77 void (*comp_reset
) (void *state
);
79 /* Compress a packet */
80 int (*compress
) (void *state
, unsigned char *rptr
,
81 unsigned char *obuf
, int isize
, int osize
);
83 /* Return compression statistics */
84 void (*comp_stat
) (void *state
, struct compstat
*stats
);
86 /* Allocate space for a decompressor (receive side) */
87 void *(*decomp_alloc
) (unsigned char *options
, int opt_len
);
89 /* Free space used by a decompressor */
90 void (*decomp_free
) (void *state
);
92 /* Initialize a decompressor */
93 int (*decomp_init
) (void *state
, unsigned char *options
,
94 int opt_len
, int unit
, int opthdr
, int mru
,
97 /* Reset a decompressor */
98 void (*decomp_reset
) (void *state
);
100 /* Decompress a packet. */
101 int (*decompress
) (void *state
, unsigned char *ibuf
, int isize
,
102 unsigned char *obuf
, int osize
);
104 /* Update state for an incompressible packet received */
105 void (*incomp
) (void *state
, unsigned char *ibuf
, int icnt
);
107 /* Return decompression statistics */
108 void (*decomp_stat
) (void *state
, struct compstat
*stats
);
110 /* Used in locking compressor modules */
111 struct module
*owner
;
112 /* Extra skb space needed by the compressor algorithm */
113 unsigned int comp_extra
;
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.
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.
128 #define DECOMP_ERROR -1 /* error detected before decomp. */
129 #define DECOMP_FATALERROR -2 /* error detected after decomp. */
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
143 * Max # bytes for a CCP option
146 #define CCP_MAX_OPTION_LENGTH 32
149 * Parts of a CCP packet.
152 #define CCP_CODE(dp) ((dp)[0])
153 #define CCP_ID(dp) ((dp)[1])
154 #define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3])
157 #define CCP_OPT_CODE(dp) ((dp)[0])
158 #define CCP_OPT_LENGTH(dp) ((dp)[1])
159 #define CCP_OPT_MINLEN 2
162 * Definitions for BSD-Compress.
165 #define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */
166 #define CILEN_BSD_COMPRESS 3 /* length of config. option */
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))
174 #define BSD_MIN_BITS 9 /* smallest code size supported */
175 #define BSD_MAX_BITS 15 /* largest code size supported */
178 * Definitions for Deflate.
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 */
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
194 * Definitions for MPPE.
197 #define CI_MPPE 18 /* config option for MPPE */
198 #define CILEN_MPPE 6 /* length of config option */
201 * Definitions for other, as yet unsupported, compression methods.
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 */
210 extern int ppp_register_compressor(struct compressor
*);
211 extern void ppp_unregister_compressor(struct compressor
*);
212 #endif /* __KERNEL__ */
214 #endif /* _NET_PPP_COMP_H */
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