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1da177e4 LT |
1 | /* |
2 | * ppp-comp.h - Definitions for doing PPP packet compression. | |
3 | * | |
784db3f0 | 4 | * Copyright 1994-1998 Paul Mackerras. |
1da177e4 | 5 | * |
784db3f0 PM |
6 | * This program is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU General Public License | |
8 | * version 2 as published by the Free Software Foundation. | |
1da177e4 | 9 | */ |
1da177e4 LT |
10 | #ifndef _NET_PPP_COMP_H |
11 | #define _NET_PPP_COMP_H | |
12 | ||
13 | struct module; | |
14 | ||
15 | /* | |
16 | * The following symbols control whether we include code for | |
17 | * various compression methods. | |
18 | */ | |
19 | ||
20 | #ifndef DO_BSD_COMPRESS | |
21 | #define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */ | |
22 | #endif | |
23 | #ifndef DO_DEFLATE | |
24 | #define DO_DEFLATE 1 /* by default, include Deflate */ | |
25 | #endif | |
26 | #define DO_PREDICTOR_1 0 | |
27 | #define DO_PREDICTOR_2 0 | |
28 | ||
29 | /* | |
30 | * Structure giving methods for compression/decompression. | |
31 | */ | |
32 | ||
33 | struct compressor { | |
34 | int compress_proto; /* CCP compression protocol number */ | |
35 | ||
36 | /* Allocate space for a compressor (transmit side) */ | |
37 | void *(*comp_alloc) (unsigned char *options, int opt_len); | |
38 | ||
39 | /* Free space used by a compressor */ | |
40 | void (*comp_free) (void *state); | |
41 | ||
42 | /* Initialize a compressor */ | |
43 | int (*comp_init) (void *state, unsigned char *options, | |
44 | int opt_len, int unit, int opthdr, int debug); | |
45 | ||
46 | /* Reset a compressor */ | |
47 | void (*comp_reset) (void *state); | |
48 | ||
49 | /* Compress a packet */ | |
50 | int (*compress) (void *state, unsigned char *rptr, | |
51 | unsigned char *obuf, int isize, int osize); | |
52 | ||
53 | /* Return compression statistics */ | |
54 | void (*comp_stat) (void *state, struct compstat *stats); | |
55 | ||
56 | /* Allocate space for a decompressor (receive side) */ | |
57 | void *(*decomp_alloc) (unsigned char *options, int opt_len); | |
58 | ||
59 | /* Free space used by a decompressor */ | |
60 | void (*decomp_free) (void *state); | |
61 | ||
62 | /* Initialize a decompressor */ | |
63 | int (*decomp_init) (void *state, unsigned char *options, | |
64 | int opt_len, int unit, int opthdr, int mru, | |
65 | int debug); | |
66 | ||
67 | /* Reset a decompressor */ | |
68 | void (*decomp_reset) (void *state); | |
69 | ||
70 | /* Decompress a packet. */ | |
71 | int (*decompress) (void *state, unsigned char *ibuf, int isize, | |
72 | unsigned char *obuf, int osize); | |
73 | ||
74 | /* Update state for an incompressible packet received */ | |
75 | void (*incomp) (void *state, unsigned char *ibuf, int icnt); | |
76 | ||
77 | /* Return decompression statistics */ | |
78 | void (*decomp_stat) (void *state, struct compstat *stats); | |
79 | ||
80 | /* Used in locking compressor modules */ | |
81 | struct module *owner; | |
b3f9b92a MD |
82 | /* Extra skb space needed by the compressor algorithm */ |
83 | unsigned int comp_extra; | |
1da177e4 LT |
84 | }; |
85 | ||
86 | /* | |
87 | * The return value from decompress routine is the length of the | |
88 | * decompressed packet if successful, otherwise DECOMP_ERROR | |
89 | * or DECOMP_FATALERROR if an error occurred. | |
90 | * | |
91 | * We need to make this distinction so that we can disable certain | |
92 | * useful functionality, namely sending a CCP reset-request as a result | |
93 | * of an error detected after decompression. This is to avoid infringing | |
94 | * a patent held by Motorola. | |
95 | * Don't you just lurve software patents. | |
96 | */ | |
97 | ||
98 | #define DECOMP_ERROR -1 /* error detected before decomp. */ | |
99 | #define DECOMP_FATALERROR -2 /* error detected after decomp. */ | |
100 | ||
101 | /* | |
102 | * CCP codes. | |
103 | */ | |
104 | ||
105 | #define CCP_CONFREQ 1 | |
106 | #define CCP_CONFACK 2 | |
107 | #define CCP_TERMREQ 5 | |
108 | #define CCP_TERMACK 6 | |
109 | #define CCP_RESETREQ 14 | |
110 | #define CCP_RESETACK 15 | |
111 | ||
112 | /* | |
113 | * Max # bytes for a CCP option | |
114 | */ | |
115 | ||
116 | #define CCP_MAX_OPTION_LENGTH 32 | |
117 | ||
118 | /* | |
119 | * Parts of a CCP packet. | |
120 | */ | |
121 | ||
122 | #define CCP_CODE(dp) ((dp)[0]) | |
123 | #define CCP_ID(dp) ((dp)[1]) | |
124 | #define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3]) | |
125 | #define CCP_HDRLEN 4 | |
126 | ||
127 | #define CCP_OPT_CODE(dp) ((dp)[0]) | |
128 | #define CCP_OPT_LENGTH(dp) ((dp)[1]) | |
129 | #define CCP_OPT_MINLEN 2 | |
130 | ||
131 | /* | |
132 | * Definitions for BSD-Compress. | |
133 | */ | |
134 | ||
135 | #define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */ | |
136 | #define CILEN_BSD_COMPRESS 3 /* length of config. option */ | |
137 | ||
138 | /* Macros for handling the 3rd byte of the BSD-Compress config option. */ | |
139 | #define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */ | |
140 | #define BSD_VERSION(x) ((x) >> 5) /* version of option format */ | |
141 | #define BSD_CURRENT_VERSION 1 /* current version number */ | |
142 | #define BSD_MAKE_OPT(v, n) (((v) << 5) | (n)) | |
143 | ||
144 | #define BSD_MIN_BITS 9 /* smallest code size supported */ | |
145 | #define BSD_MAX_BITS 15 /* largest code size supported */ | |
146 | ||
147 | /* | |
148 | * Definitions for Deflate. | |
149 | */ | |
150 | ||
151 | #define CI_DEFLATE 26 /* config option for Deflate */ | |
152 | #define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */ | |
153 | #define CILEN_DEFLATE 4 /* length of its config option */ | |
154 | ||
155 | #define DEFLATE_MIN_SIZE 9 | |
156 | #define DEFLATE_MAX_SIZE 15 | |
157 | #define DEFLATE_METHOD_VAL 8 | |
158 | #define DEFLATE_SIZE(x) (((x) >> 4) + 8) | |
159 | #define DEFLATE_METHOD(x) ((x) & 0x0F) | |
160 | #define DEFLATE_MAKE_OPT(w) ((((w) - 8) << 4) + DEFLATE_METHOD_VAL) | |
161 | #define DEFLATE_CHK_SEQUENCE 0 | |
162 | ||
b3f9b92a MD |
163 | /* |
164 | * Definitions for MPPE. | |
165 | */ | |
166 | ||
167 | #define CI_MPPE 18 /* config option for MPPE */ | |
168 | #define CILEN_MPPE 6 /* length of config option */ | |
169 | ||
1da177e4 LT |
170 | /* |
171 | * Definitions for other, as yet unsupported, compression methods. | |
172 | */ | |
173 | ||
174 | #define CI_PREDICTOR_1 1 /* config option for Predictor-1 */ | |
175 | #define CILEN_PREDICTOR_1 2 /* length of its config option */ | |
176 | #define CI_PREDICTOR_2 2 /* config option for Predictor-2 */ | |
177 | #define CILEN_PREDICTOR_2 2 /* length of its config option */ | |
178 | ||
179 | #ifdef __KERNEL__ | |
180 | extern int ppp_register_compressor(struct compressor *); | |
181 | extern void ppp_unregister_compressor(struct compressor *); | |
182 | #endif /* __KERNEL__ */ | |
183 | ||
184 | #endif /* _NET_PPP_COMP_H */ |