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ppp-comp.h revision 1.14
      1 /*	$NetBSD: ppp-comp.h,v 1.14 2008/02/20 17:05:53 matt 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 (at) 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 struct compressor {
     66 	int	compress_proto;	/* CCP compression protocol number */
     67 
     68 	/* Allocate space for a compressor (transmit side) */
     69 	void	*(*comp_alloc)(u_char *, int);
     70 	/* Free space used by a compressor */
     71 	void	(*comp_free)(void *);
     72 	/* Initialize a compressor */
     73 	int	(*comp_init)(void *, u_char *, int, int, int, int);
     74 	/* Reset a compressor */
     75 	void	(*comp_reset)(void *);
     76 	/* Compress a packet */
     77 	int	(*compress)(void *, PACKETPTR *, PACKETPTR, int, int);
     78 	/* Return compression statistics */
     79 	void	(*comp_stat)(void *, struct compstat *);
     80 
     81 	/* Allocate space for a decompressor (receive side) */
     82 	void	*(*decomp_alloc)(u_char *, int);
     83 	/* Free space used by a decompressor */
     84 	void	(*decomp_free)(void *);
     85 	/* Initialize a decompressor */
     86 	int	(*decomp_init)(void *, u_char *, int, int, int, int, int);
     87 	/* Reset a decompressor */
     88 	void	(*decomp_reset)(void *);
     89 	/* Decompress a packet. */
     90 	int	(*decompress)(void *, PACKETPTR, PACKETPTR *);
     91 	/* Update state for an incompressible packet received */
     92 	void	(*incomp)(void *, PACKETPTR);
     93 	/* Return decompression statistics */
     94 	void	(*decomp_stat)(void *, struct compstat *);
     95 };
     96 #endif /* PACKETPTR */
     97 
     98 /*
     99  * Return values for decompress routine.
    100  * We need to make these distinctions so that we can disable certain
    101  * useful functionality, namely sending a CCP reset-request as a result
    102  * of an error detected after decompression.  This is to avoid infringing
    103  * a patent held by Motorola.
    104  * Don't you just lurve software patents.
    105  */
    106 #define DECOMP_OK		0	/* everything went OK */
    107 #define DECOMP_ERROR		1	/* error detected before decomp. */
    108 #define DECOMP_FATALERROR	2	/* error detected after decomp. */
    109 
    110 /*
    111  * CCP codes.
    112  */
    113 #define CCP_CONFREQ	1
    114 #define CCP_CONFACK	2
    115 #define	CCP_CONFNAK	3
    116 #define	CCP_CONFREJ	4
    117 #define CCP_TERMREQ	5
    118 #define CCP_TERMACK	6
    119 #define CCP_RESETREQ	14
    120 #define CCP_RESETACK	15
    121 
    122 /*
    123  * Max # bytes for a CCP option
    124  */
    125 #define CCP_MAX_OPTION_LENGTH	64
    126 
    127 /*
    128  * Parts of a CCP packet.
    129  */
    130 #define CCP_CODE(dp)		((dp)[0])
    131 #define CCP_ID(dp)		((dp)[1])
    132 #define CCP_LENGTH(dp)		(((dp)[2] << 8) + (dp)[3])
    133 #define CCP_HDRLEN		4
    134 
    135 #define CCP_OPT_CODE(dp)	((dp)[0])
    136 #define CCP_OPT_LENGTH(dp)	((dp)[1])
    137 #define CCP_OPT_MINLEN		2
    138 
    139 /*
    140  * Definitions for BSD-Compress.
    141  */
    142 #define CI_BSD_COMPRESS		21	/* config. option for BSD-Compress */
    143 #define CILEN_BSD_COMPRESS	3	/* length of config. option */
    144 
    145 /* Macros for handling the 3rd byte of the BSD-Compress config option. */
    146 #define BSD_NBITS(x)		((x) & 0x1F)	/* number of bits requested */
    147 #define BSD_VERSION(x)		((x) >> 5)	/* version of option format */
    148 #define BSD_CURRENT_VERSION	1		/* current version number */
    149 #define BSD_MAKE_OPT(v, n)	(((v) << 5) | (n))
    150 
    151 #define BSD_MIN_BITS		9	/* smallest code size supported */
    152 #define BSD_MAX_BITS		15	/* largest code size supported */
    153 
    154 /*
    155  * Definitions for Deflate.
    156  */
    157 #define CI_DEFLATE		26	/* config option for Deflate */
    158 #define CI_DEFLATE_DRAFT	24	/* value used in original draft RFC */
    159 
    160 #define CILEN_DEFLATE		4	/* length of its config option */
    161 
    162 #define DEFLATE_MIN_SIZE	8
    163 #define DEFLATE_MAX_SIZE	15
    164 #define DEFLATE_METHOD_VAL	8
    165 #define DEFLATE_SIZE(x)		(((x) >> 4) + DEFLATE_MIN_SIZE)
    166 #define DEFLATE_METHOD(x)	((x) & 0x0F)
    167 #define DEFLATE_MAKE_OPT(w)	((((w) - DEFLATE_MIN_SIZE) << 4) \
    168 				 + DEFLATE_METHOD_VAL)
    169 #define DEFLATE_CHK_SEQUENCE	0
    170 
    171 /*
    172  * Definitions for MPPE.
    173  */
    174 #define CI_MPPE			18	/* config option for MPPE */
    175 #define CILEN_MPPE		6	/* length of config option */
    176 
    177 #define MPPE_PAD		4	/* MPPE growth per frame */
    178 #define MPPE_MAX_KEY_LEN	16	/* largest key length (128-bit) */
    179 
    180 /* option bits for ccp_options.mppe */
    181 #define MPPE_OPT_40		0x01	/* 40 bit */
    182 #define MPPE_OPT_128		0x02	/* 128 bit */
    183 #define MPPE_OPT_STATEFUL	0x04	/* stateful mode */
    184 /* unsupported opts */
    185 #define MPPE_OPT_56		0x08	/* 56 bit */
    186 #define MPPE_OPT_MPPC		0x10	/* MPPC compression */
    187 #define MPPE_OPT_D		0x20	/* Unknown */
    188 #define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
    189 #define MPPE_OPT_UNKNOWN	0x40	/* Bits !defined in RFC 3078 were set */
    190 
    191 /*
    192  * This is not nice ... the alternative is a bitfield struct though.
    193  * And unfortunately, we cannot share the same bits for the option
    194  * names above since C and H are the same bit.  We could do a uint32_t
    195  * but then we have to do a htonl() all the time and/or we still need
    196  * to know which octet is which.
    197  */
    198 #define MPPE_C_BIT		0x01	/* MPPC */
    199 #define MPPE_D_BIT		0x10	/* Obsolete, usage unknown */
    200 #define MPPE_L_BIT		0x20	/* 40-bit */
    201 #define MPPE_S_BIT		0x40	/* 128-bit */
    202 #define MPPE_M_BIT		0x80	/* 56-bit, not supported */
    203 #define MPPE_H_BIT		0x01	/* Stateless (in a different byte) */
    204 
    205 /* Does not include H bit; used for least significant octet only. */
    206 #define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
    207 
    208 /* Build a CI from mppe opts (see RFC 3078) */
    209 #define MPPE_OPTS_TO_CI(opts, ci)		\
    210     do {					\
    211 	u_char *ptr = ci; /* u_char[4] */	\
    212 						\
    213 	/* H bit */				\
    214 	if (opts & MPPE_OPT_STATEFUL)		\
    215 	    *ptr++ = 0x0;			\
    216 	else					\
    217 	    *ptr++ = MPPE_H_BIT;		\
    218 	*ptr++ = 0;				\
    219 	*ptr++ = 0;				\
    220 						\
    221 	/* S,L bits */				\
    222 	*ptr = 0;				\
    223 	if (opts & MPPE_OPT_128)		\
    224 	    *ptr |= MPPE_S_BIT;			\
    225 	if (opts & MPPE_OPT_40)			\
    226 	    *ptr |= MPPE_L_BIT;			\
    227 	/* M,D,C bits not supported */		\
    228     } while (/* CONSTCOND */ 0)
    229 
    230 /* The reverse of the above */
    231 #define MPPE_CI_TO_OPTS(ci, opts)		\
    232     do {					\
    233 	u_char *ptr = ci; /* u_char[4] */	\
    234 						\
    235 	opts = 0;				\
    236 						\
    237 	/* H bit */				\
    238 	if (!(ptr[0] & MPPE_H_BIT))		\
    239 	    opts |= MPPE_OPT_STATEFUL;		\
    240 						\
    241 	/* S,L bits */				\
    242 	if (ptr[3] & MPPE_S_BIT)		\
    243 	    opts |= MPPE_OPT_128;		\
    244 	if (ptr[3] & MPPE_L_BIT)		\
    245 	    opts |= MPPE_OPT_40;		\
    246 						\
    247 	/* M,D,C bits */			\
    248 	if (ptr[3] & MPPE_M_BIT)		\
    249 	    opts |= MPPE_OPT_56;		\
    250 	if (ptr[3] & MPPE_D_BIT)		\
    251 	    opts |= MPPE_OPT_D;			\
    252 	if (ptr[3] & MPPE_C_BIT)		\
    253 	    opts |= MPPE_OPT_MPPC;		\
    254 						\
    255 	/* Other bits */			\
    256 	if (ptr[0] & ~MPPE_H_BIT)		\
    257 	    opts |= MPPE_OPT_UNKNOWN;		\
    258 	if (ptr[1] || ptr[2])			\
    259 	    opts |= MPPE_OPT_UNKNOWN;		\
    260 	if (ptr[3] & ~MPPE_ALL_BITS)		\
    261 	    opts |= MPPE_OPT_UNKNOWN;		\
    262     } while (/* CONSTCOND */ 0)
    263 
    264 /*
    265  * Definitions for other, as yet unsupported, compression methods.
    266  */
    267 #define CI_PREDICTOR_1		1	/* config option for Predictor-1 */
    268 #define CILEN_PREDICTOR_1	2	/* length of its config option */
    269 #define CI_PREDICTOR_2		2	/* config option for Predictor-2 */
    270 #define CILEN_PREDICTOR_2	2	/* length of its config option */
    271 
    272 #endif /* !_NET_PPP_COMP_H_ */
    273