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_ */