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mppe.h revision 1.4 
      1 /*	$NetBSD: mppe.h,v 1.4 2014/10/25 21:11:37 christos Exp $	*/
      2 
      3 /*
      4  * mppe.h - Definitions for MPPE
      5  *
      6  * Copyright (c) 2008 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 #define MPPE_PAD		4	/* MPPE growth per frame */
     39 #define MPPE_MAX_KEY_LEN	16	/* largest key length (128-bit) */
     40 
     41 /* option bits for ccp_options.mppe */
     42 #define MPPE_OPT_40		0x01	/* 40 bit */
     43 #define MPPE_OPT_128		0x02	/* 128 bit */
     44 #define MPPE_OPT_STATEFUL	0x04	/* stateful mode */
     45 /* unsupported opts */
     46 #define MPPE_OPT_56		0x08	/* 56 bit */
     47 #define MPPE_OPT_MPPC		0x10	/* MPPC compression */
     48 #define MPPE_OPT_D		0x20	/* Unknown */
     49 #define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
     50 #define MPPE_OPT_UNKNOWN	0x40	/* Bits !defined in RFC 3078 were set */
     51 
     52 /*
     53  * This is not nice ... the alternative is a bitfield struct though.
     54  * And unfortunately, we cannot share the same bits for the option
     55  * names above since C and H are the same bit.  We could do a u_int32
     56  * but then we have to do a htonl() all the time and/or we still need
     57  * to know which octet is which.
     58  */
     59 #define MPPE_C_BIT		0x01	/* MPPC */
     60 #define MPPE_D_BIT		0x10	/* Obsolete, usage unknown */
     61 #define MPPE_L_BIT		0x20	/* 40-bit */
     62 #define MPPE_S_BIT		0x40	/* 128-bit */
     63 #define MPPE_M_BIT		0x80	/* 56-bit, not supported */
     64 #define MPPE_H_BIT		0x01	/* Stateless (in a different byte) */
     65 
     66 /* Does not include H bit; used for least significant octet only. */
     67 #define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
     68 
     69 /* Build a CI from mppe opts (see RFC 3078) */
     70 #define MPPE_OPTS_TO_CI(opts, ci)		\
     71     do {					\
     72 	u_char *ptr = ci; /* u_char[4] */	\
     73 						\
     74 	/* H bit */				\
     75 	if (opts & MPPE_OPT_STATEFUL)		\
     76 	    *ptr++ = 0x0;			\
     77 	else					\
     78 	    *ptr++ = MPPE_H_BIT;		\
     79 	*ptr++ = 0;				\
     80 	*ptr++ = 0;				\
     81 						\
     82 	/* S,L bits */				\
     83 	*ptr = 0;				\
     84 	if (opts & MPPE_OPT_128)		\
     85 	    *ptr |= MPPE_S_BIT;			\
     86 	if (opts & MPPE_OPT_40)			\
     87 	    *ptr |= MPPE_L_BIT;			\
     88 	/* M,D,C bits not supported */		\
     89     } while (/* CONSTCOND */ 0)
     90 
     91 /* The reverse of the above */
     92 #define MPPE_CI_TO_OPTS(ci, opts)		\
     93     do {					\
     94 	u_char *ptr = ci; /* u_char[4] */	\
     95 						\
     96 	opts = 0;				\
     97 						\
     98 	/* H bit */				\
     99 	if (!(ptr[0] & MPPE_H_BIT))		\
    100 	    opts |= MPPE_OPT_STATEFUL;		\
    101 						\
    102 	/* S,L bits */				\
    103 	if (ptr[3] & MPPE_S_BIT)		\
    104 	    opts |= MPPE_OPT_128;		\
    105 	if (ptr[3] & MPPE_L_BIT)		\
    106 	    opts |= MPPE_OPT_40;		\
    107 						\
    108 	/* M,D,C bits */			\
    109 	if (ptr[3] & MPPE_M_BIT)		\
    110 	    opts |= MPPE_OPT_56;		\
    111 	if (ptr[3] & MPPE_D_BIT)		\
    112 	    opts |= MPPE_OPT_D;			\
    113 	if (ptr[3] & MPPE_C_BIT)		\
    114 	    opts |= MPPE_OPT_MPPC;		\
    115 						\
    116 	/* Other bits */			\
    117 	if (ptr[0] & ~MPPE_H_BIT)		\
    118 	    opts |= MPPE_OPT_UNKNOWN;		\
    119 	if (ptr[1] || ptr[2])			\
    120 	    opts |= MPPE_OPT_UNKNOWN;		\
    121 	if (ptr[3] & ~MPPE_ALL_BITS)		\
    122 	    opts |= MPPE_OPT_UNKNOWN;		\
    123     } while (/* CONSTCOND */ 0)
    124