1/*
2 * mppe.h - Definitions for MPPE
3 *
4 * Copyright (c) 2008 Paul Mackerras. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in
15 *    the documentation and/or other materials provided with the
16 *    distribution.
17 *
18 * 3. The name(s) of the authors of this software must not be used to
19 *    endorse or promote products derived from this software without
20 *    prior written permission.
21 *
22 * 4. Redistributions of any form whatsoever must retain the following
23 *    acknowledgment:
24 *    "This product includes software developed by Paul Mackerras
25 *     <paulus@samba.org>".
26 *
27 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
28 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
29 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
30 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
31 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
32 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
33 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
34 */
35
36#define MPPE_PAD		4	/* MPPE growth per frame */
37#define MPPE_MAX_KEY_LEN	16	/* largest key length (128-bit) */
38
39/* option bits for ccp_options.mppe */
40#define MPPE_OPT_40		0x01	/* 40 bit */
41#define MPPE_OPT_128		0x02	/* 128 bit */
42#define MPPE_OPT_STATEFUL	0x04	/* stateful mode */
43/* unsupported opts */
44#define MPPE_OPT_56		0x08	/* 56 bit */
45#define MPPE_OPT_MPPC		0x10	/* MPPC compression */
46#define MPPE_OPT_D		0x20	/* Unknown */
47#define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
48#define MPPE_OPT_UNKNOWN	0x40	/* Bits !defined in RFC 3078 were set */
49
50/*
51 * This is not nice ... the alternative is a bitfield struct though.
52 * And unfortunately, we cannot share the same bits for the option
53 * names above since C and H are the same bit.  We could do a u_int32
54 * but then we have to do a htonl() all the time and/or we still need
55 * to know which octet is which.
56 */
57#define MPPE_C_BIT		0x01	/* MPPC */
58#define MPPE_D_BIT		0x10	/* Obsolete, usage unknown */
59#define MPPE_L_BIT		0x20	/* 40-bit */
60#define MPPE_S_BIT		0x40	/* 128-bit */
61#define MPPE_M_BIT		0x80	/* 56-bit, not supported */
62#define MPPE_H_BIT		0x01	/* Stateless (in a different byte) */
63
64/* Does not include H bit; used for least significant octet only. */
65#define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
66
67/* Build a CI from mppe opts (see RFC 3078) */
68#define MPPE_OPTS_TO_CI(opts, ci)		\
69    do {					\
70	u_char *ptr = ci; /* u_char[4] */	\
71						\
72	/* H bit */				\
73	if (opts & MPPE_OPT_STATEFUL)		\
74	    *ptr++ = 0x0;			\
75	else					\
76	    *ptr++ = MPPE_H_BIT;		\
77	*ptr++ = 0;				\
78	*ptr++ = 0;				\
79						\
80	/* S,L bits */				\
81	*ptr = 0;				\
82	if (opts & MPPE_OPT_128)		\
83	    *ptr |= MPPE_S_BIT;			\
84	if (opts & MPPE_OPT_40)			\
85	    *ptr |= MPPE_L_BIT;			\
86	/* M,D,C bits not supported */		\
87    } while (/* CONSTCOND */ 0)
88
89/* The reverse of the above */
90#define MPPE_CI_TO_OPTS(ci, opts)		\
91    do {					\
92	u_char *ptr = ci; /* u_char[4] */	\
93						\
94	opts = 0;				\
95						\
96	/* H bit */				\
97	if (!(ptr[0] & MPPE_H_BIT))		\
98	    opts |= MPPE_OPT_STATEFUL;		\
99						\
100	/* S,L bits */				\
101	if (ptr[3] & MPPE_S_BIT)		\
102	    opts |= MPPE_OPT_128;		\
103	if (ptr[3] & MPPE_L_BIT)		\
104	    opts |= MPPE_OPT_40;		\
105						\
106	/* M,D,C bits */			\
107	if (ptr[3] & MPPE_M_BIT)		\
108	    opts |= MPPE_OPT_56;		\
109	if (ptr[3] & MPPE_D_BIT)		\
110	    opts |= MPPE_OPT_D;			\
111	if (ptr[3] & MPPE_C_BIT)		\
112	    opts |= MPPE_OPT_MPPC;		\
113						\
114	/* Other bits */			\
115	if (ptr[0] & ~MPPE_H_BIT)		\
116	    opts |= MPPE_OPT_UNKNOWN;		\
117	if (ptr[1] || ptr[2])			\
118	    opts |= MPPE_OPT_UNKNOWN;		\
119	if (ptr[3] & ~MPPE_ALL_BITS)		\
120	    opts |= MPPE_OPT_UNKNOWN;		\
121    } while (/* CONSTCOND */ 0)
122