1/*	$NetBSD$	*/
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@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