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,
27 * $Id: ppp-comp.h,v 1.9 2002/04/02 13:54:59 dfs Exp $
31 * ==FILEVERSION 20020319==
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.
42 #ifndef _NET_PPP_COMP_H
43 #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);
112 * The return value from decompress routine is the length of the
113 * decompressed packet if successful, otherwise DECOMP_ERROR
114 * or DECOMP_FATALERROR if an error occurred.
116 * We need to make this distinction so that we can disable certain
117 * useful functionality, namely sending a CCP reset-request as a result
118 * of an error detected after decompression. This is to avoid infringing
119 * a patent held by Motorola.
120 * Don't you just lurve software patents.
123 #define DECOMP_ERROR -1 /* error detected before decomp. */
124 #define DECOMP_FATALERROR -2 /* error detected after decomp. */
130 #define CCP_CONFREQ 1
131 #define CCP_CONFACK 2
132 #define CCP_TERMREQ 5
133 #define CCP_TERMACK 6
134 #define CCP_RESETREQ 14
135 #define CCP_RESETACK 15
138 * Max # bytes for a CCP option
141 #define CCP_MAX_OPTION_LENGTH 32
144 * Parts of a CCP packet.
147 #define CCP_CODE(dp) ((dp)[0])
148 #define CCP_ID(dp) ((dp)[1])
149 #define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3])
152 #define CCP_OPT_CODE(dp) ((dp)[0])
153 #define CCP_OPT_LENGTH(dp) ((dp)[1])
154 #define CCP_OPT_MINLEN 2
157 * Definitions for BSD-Compress.
160 #define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */
161 #define CILEN_BSD_COMPRESS 3 /* length of config. option */
163 /* Macros for handling the 3rd byte of the BSD-Compress config option. */
164 #define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */
165 #define BSD_VERSION(x) ((x) >> 5) /* version of option format */
166 #define BSD_CURRENT_VERSION 1 /* current version number */
167 #define BSD_MAKE_OPT(v, n) (((v) << 5) | (n))
169 #define BSD_MIN_BITS 9 /* smallest code size supported */
170 #define BSD_MAX_BITS 15 /* largest code size supported */
173 * Definitions for Deflate.
176 #define CI_DEFLATE 26 /* config option for Deflate */
177 #define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */
178 #define CILEN_DEFLATE 4 /* length of its config option */
180 #define DEFLATE_MIN_SIZE 8
181 #define DEFLATE_MAX_SIZE 15
182 #define DEFLATE_METHOD_VAL 8
183 #define DEFLATE_SIZE(x) (((x) >> 4) + DEFLATE_MIN_SIZE)
184 #define DEFLATE_METHOD(x) ((x) & 0x0F)
185 #define DEFLATE_MAKE_OPT(w) ((((w) - DEFLATE_MIN_SIZE) << 4) \
186 + DEFLATE_METHOD_VAL)
187 #define DEFLATE_CHK_SEQUENCE 0
190 * Definitions for MPPE.
193 #define CI_MPPE 18 /* config option for MPPE */
194 #define CILEN_MPPE 6 /* length of config option */
196 #define MPPE_PAD 4 /* MPPE growth per frame */
197 #define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */
199 /* option bits for ccp_options.mppe */
200 #define MPPE_OPT_40 0x01 /* 40 bit */
201 #define MPPE_OPT_128 0x02 /* 128 bit */
202 #define MPPE_OPT_STATEFUL 0x04 /* stateful mode */
203 /* unsupported opts */
204 #define MPPE_OPT_56 0x08 /* 56 bit */
205 #define MPPE_OPT_MPPC 0x10 /* MPPC compression */
206 #define MPPE_OPT_D 0x20 /* Unknown */
207 #define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
208 #define MPPE_OPT_UNKNOWN 0x40 /* Bits !defined in RFC 3078 were set */
211 * This is not nice ... the alternative is a bitfield struct though.
212 * And unfortunately, we cannot share the same bits for the option
213 * names above since C and H are the same bit. We could do a u_int32
214 * but then we have to do a htonl() all the time and/or we still need
215 * to know which octet is which.
217 #define MPPE_C_BIT 0x01 /* MPPC */
218 #define MPPE_D_BIT 0x10 /* Obsolete, usage unknown */
219 #define MPPE_L_BIT 0x20 /* 40-bit */
220 #define MPPE_S_BIT 0x40 /* 128-bit */
221 #define MPPE_M_BIT 0x80 /* 56-bit, not supported */
222 #define MPPE_H_BIT 0x01 /* Stateless (in a different byte) */
224 /* Does not include H bit; used for least significant octet only. */
225 #define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
227 /* Build a CI from mppe opts (see RFC 3078) */
228 #define MPPE_OPTS_TO_CI(opts, ci) \
230 u_char *ptr = ci; /* u_char[4] */ \
233 if (opts & MPPE_OPT_STATEFUL) \
236 *ptr++ = MPPE_H_BIT; \
242 if (opts & MPPE_OPT_128) \
243 *ptr |= MPPE_S_BIT; \
244 if (opts & MPPE_OPT_40) \
245 *ptr |= MPPE_L_BIT; \
246 /* M,D,C bits not supported */ \
247 } while (/* CONSTCOND */ 0)
249 /* The reverse of the above */
250 #define MPPE_CI_TO_OPTS(ci, opts) \
252 u_char *ptr = ci; /* u_char[4] */ \
257 if (!(ptr[0] & MPPE_H_BIT)) \
258 opts |= MPPE_OPT_STATEFUL; \
261 if (ptr[3] & MPPE_S_BIT) \
262 opts |= MPPE_OPT_128; \
263 if (ptr[3] & MPPE_L_BIT) \
264 opts |= MPPE_OPT_40; \
267 if (ptr[3] & MPPE_M_BIT) \
268 opts |= MPPE_OPT_56; \
269 if (ptr[3] & MPPE_D_BIT) \
270 opts |= MPPE_OPT_D; \
271 if (ptr[3] & MPPE_C_BIT) \
272 opts |= MPPE_OPT_MPPC; \
275 if (ptr[0] & ~MPPE_H_BIT) \
276 opts |= MPPE_OPT_UNKNOWN; \
277 if (ptr[1] || ptr[2]) \
278 opts |= MPPE_OPT_UNKNOWN; \
279 if (ptr[3] & ~MPPE_ALL_BITS) \
280 opts |= MPPE_OPT_UNKNOWN; \
281 } while (/* CONSTCOND */ 0)
284 * Definitions for other, as yet unsupported, compression methods.
287 #define CI_PREDICTOR_1 1 /* config option for Predictor-1 */
288 #define CILEN_PREDICTOR_1 2 /* length of its config option */
289 #define CI_PREDICTOR_2 2 /* config option for Predictor-2 */
290 #define CILEN_PREDICTOR_2 2 /* length of its config option */
293 extern int ppp_register_compressor(struct compressor *);
294 extern void ppp_unregister_compressor(struct compressor *);
295 #endif /* __KERNEL__ */
297 #endif /* _NET_PPP_COMP_H */