1/* $NetBSD: ppp-comp.h,v 1.16 2008/11/29 23:15:20 cube Exp $ */
2
3/*
4 * ppp-comp.h - Definitions for doing PPP packet compression.
5 *
6 * Copyright (c) 1989-2002 Paul Mackerras. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. The name(s) of the authors of this software must not be used to
21 * endorse or promote products derived from this software without
22 * prior written permission.
23 *
24 * 4. Redistributions of any form whatsoever must retain the following
25 * acknowledgment:
26 * "This product includes software developed by Paul Mackerras
27 * <paulus@samba.org>".
28 *
29 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
30 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
31 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
32 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
33 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
34 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
35 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
36 */
37
38#ifndef _NET_PPP_COMP_H_
39#define _NET_PPP_COMP_H_
40
41/*
42 * The following symbols control whether we include code for
43 * various compression methods.
44 */
45#ifndef DO_BSD_COMPRESS
46#define DO_BSD_COMPRESS 1 /* by default, include BSD-Compress */
47#endif
48#ifndef DO_DEFLATE
49#define DO_DEFLATE 1 /* by default, include Deflate */
50#endif
51#define DO_PREDICTOR_1 0
52#define DO_PREDICTOR_2 0
53
54/*
55 * How many entries to make available in the compressors table
56 */
57#ifndef PPP_COMPRESSORS_MAX
58#define PPP_COMPRESSORS_MAX 8
59#endif
60
61/*
62 * Structure giving methods for compression/decompression.
63 */
64#ifdef PACKETPTR
65#include <sys/queue.h>
66
67struct compressor {
68 int compress_proto; /* CCP compression protocol number */
69
70 /* Allocate space for a compressor (transmit side) */
71 void *(*comp_alloc)(u_char *, int);
72 /* Free space used by a compressor */
73 void (*comp_free)(void *);
74 /* Initialize a compressor */
75 int (*comp_init)(void *, u_char *, int, int, int, int);
76 /* Reset a compressor */
77 void (*comp_reset)(void *);
78 /* Compress a packet */
79 int (*compress)(void *, PACKETPTR *, PACKETPTR, int, int);
80 /* Return compression statistics */
81 void (*comp_stat)(void *, struct compstat *);
82
83 /* Allocate space for a decompressor (receive side) */
84 void *(*decomp_alloc)(u_char *, int);
85 /* Free space used by a decompressor */
86 void (*decomp_free)(void *);
87 /* Initialize a decompressor */
88 int (*decomp_init)(void *, u_char *, int, int, int, int, int);
89 /* Reset a decompressor */
90 void (*decomp_reset)(void *);
91 /* Decompress a packet. */
92 int (*decompress)(void *, PACKETPTR, PACKETPTR *);
93 /* Update state for an incompressible packet received */
94 void (*incomp)(void *, PACKETPTR);
95 /* Return decompression statistics */
96 void (*decomp_stat)(void *, struct compstat *);
97
98 LIST_ENTRY(compressor) comp_list;
99 unsigned int comp_refcnt;
100};
101#endif /* PACKETPTR */
102
103/*
104 * Return values for decompress routine.
105 * We need to make these distinctions so that we can disable certain
106 * useful functionality, namely sending a CCP reset-request as a result
107 * of an error detected after decompression. This is to avoid infringing
108 * a patent held by Motorola.
109 * Don't you just lurve software patents.
110 */
111#define DECOMP_OK 0 /* everything went OK */
112#define DECOMP_ERROR 1 /* error detected before decomp. */
113#define DECOMP_FATALERROR 2 /* error detected after decomp. */
114
115/*
116 * CCP codes.
117 */
118#define CCP_CONFREQ 1
119#define CCP_CONFACK 2
120#define CCP_CONFNAK 3
121#define CCP_CONFREJ 4
122#define CCP_TERMREQ 5
123#define CCP_TERMACK 6
124#define CCP_RESETREQ 14
125#define CCP_RESETACK 15
126
127/*
128 * Max # bytes for a CCP option
129 */
130#define CCP_MAX_OPTION_LENGTH 64
131
132/*
133 * Parts of a CCP packet.
134 */
135#define CCP_CODE(dp) ((dp)[0])
136#define CCP_ID(dp) ((dp)[1])
137#define CCP_LENGTH(dp) (((dp)[2] << 8) + (dp)[3])
138#define CCP_HDRLEN 4
139
140#define CCP_OPT_CODE(dp) ((dp)[0])
141#define CCP_OPT_LENGTH(dp) ((dp)[1])
142#define CCP_OPT_MINLEN 2
143
144/*
145 * Definitions for BSD-Compress.
146 */
147#define CI_BSD_COMPRESS 21 /* config. option for BSD-Compress */
148#define CILEN_BSD_COMPRESS 3 /* length of config. option */
149
150/* Macros for handling the 3rd byte of the BSD-Compress config option. */
151#define BSD_NBITS(x) ((x) & 0x1F) /* number of bits requested */
152#define BSD_VERSION(x) ((x) >> 5) /* version of option format */
153#define BSD_CURRENT_VERSION 1 /* current version number */
154#define BSD_MAKE_OPT(v, n) (((v) << 5) | (n))
155
156#define BSD_MIN_BITS 9 /* smallest code size supported */
157#define BSD_MAX_BITS 15 /* largest code size supported */
158
159/*
160 * Definitions for Deflate.
161 */
162#define CI_DEFLATE 26 /* config option for Deflate */
163#define CI_DEFLATE_DRAFT 24 /* value used in original draft RFC */
164
165#define CILEN_DEFLATE 4 /* length of its config option */
166
167#define DEFLATE_MIN_SIZE 8
168#define DEFLATE_MAX_SIZE 15
169#define DEFLATE_METHOD_VAL 8
170#define DEFLATE_SIZE(x) (((x) >> 4) + DEFLATE_MIN_SIZE)
171#define DEFLATE_METHOD(x) ((x) & 0x0F)
172#define DEFLATE_MAKE_OPT(w) ((((w) - DEFLATE_MIN_SIZE) << 4) \
173 + DEFLATE_METHOD_VAL)
174#define DEFLATE_CHK_SEQUENCE 0
175
176/*
177 * Definitions for MPPE.
178 */
179#define CI_MPPE 18 /* config option for MPPE */
180#define CILEN_MPPE 6 /* length of config option */
181
182#define MPPE_PAD 4 /* MPPE growth per frame */
183#define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */
184
185/* option bits for ccp_options.mppe */
186#define MPPE_OPT_40 0x01 /* 40 bit */
187#define MPPE_OPT_128 0x02 /* 128 bit */
188#define MPPE_OPT_STATEFUL 0x04 /* stateful mode */
189/* unsupported opts */
190#define MPPE_OPT_56 0x08 /* 56 bit */
191#define MPPE_OPT_MPPC 0x10 /* MPPC compression */
192#define MPPE_OPT_D 0x20 /* Unknown */
193#define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
194#define MPPE_OPT_UNKNOWN 0x40 /* Bits !defined in RFC 3078 were set */
195
196/*
197 * This is not nice ... the alternative is a bitfield struct though.
198 * And unfortunately, we cannot share the same bits for the option
199 * names above since C and H are the same bit. We could do a uint32_t
200 * but then we have to do a htonl() all the time and/or we still need
201 * to know which octet is which.
202 */
203#define MPPE_C_BIT 0x01 /* MPPC */
204#define MPPE_D_BIT 0x10 /* Obsolete, usage unknown */
205#define MPPE_L_BIT 0x20 /* 40-bit */
206#define MPPE_S_BIT 0x40 /* 128-bit */
207#define MPPE_M_BIT 0x80 /* 56-bit, not supported */
208#define MPPE_H_BIT 0x01 /* Stateless (in a different byte) */
209
210/* Does not include H bit; used for least significant octet only. */
211#define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
212
213/* Build a CI from mppe opts (see RFC 3078) */
214#define MPPE_OPTS_TO_CI(opts, ci) \
215 do { \
216 u_char *ptr = ci; /* u_char[4] */ \
217 \
218 /* H bit */ \
219 if (opts & MPPE_OPT_STATEFUL) \
220 *ptr++ = 0x0; \
221 else \
222 *ptr++ = MPPE_H_BIT; \
223 *ptr++ = 0; \
224 *ptr++ = 0; \
225 \
226 /* S,L bits */ \
227 *ptr = 0; \
228 if (opts & MPPE_OPT_128) \
229 *ptr |= MPPE_S_BIT; \
230 if (opts & MPPE_OPT_40) \
231 *ptr |= MPPE_L_BIT; \
232 /* M,D,C bits not supported */ \
233 } while (/* CONSTCOND */ 0)
234
235/* The reverse of the above */
236#define MPPE_CI_TO_OPTS(ci, opts) \
237 do { \
238 u_char *ptr = ci; /* u_char[4] */ \
239 \
240 opts = 0; \
241 \
242 /* H bit */ \
243 if (!(ptr[0] & MPPE_H_BIT)) \
244 opts |= MPPE_OPT_STATEFUL; \
245 \
246 /* S,L bits */ \
247 if (ptr[3] & MPPE_S_BIT) \
248 opts |= MPPE_OPT_128; \
249 if (ptr[3] & MPPE_L_BIT) \
250 opts |= MPPE_OPT_40; \
251 \
252 /* M,D,C bits */ \
253 if (ptr[3] & MPPE_M_BIT) \
254 opts |= MPPE_OPT_56; \
255 if (ptr[3] & MPPE_D_BIT) \
256 opts |= MPPE_OPT_D; \
257 if (ptr[3] & MPPE_C_BIT) \
258 opts |= MPPE_OPT_MPPC; \
259 \
260 /* Other bits */ \
261 if (ptr[0] & ~MPPE_H_BIT) \
262 opts |= MPPE_OPT_UNKNOWN; \
263 if (ptr[1] || ptr[2]) \
264 opts |= MPPE_OPT_UNKNOWN; \
265 if (ptr[3] & ~MPPE_ALL_BITS) \
266 opts |= MPPE_OPT_UNKNOWN; \
267 } while (/* CONSTCOND */ 0)
268
269/*
270 * Definitions for other, as yet unsupported, compression methods.
271 */
272#define CI_PREDICTOR_1 1 /* config option for Predictor-1 */
273#define CILEN_PREDICTOR_1 2 /* length of its config option */
274#define CI_PREDICTOR_2 2 /* config option for Predictor-2 */
275#define CILEN_PREDICTOR_2 2 /* length of its config option */
276
277#endif /* !_NET_PPP_COMP_H_ */
278