1 /* SPDX-License-Identifier: GPL-2.0 */
2 #define MPPE_PAD 4 /* MPPE growth per frame */
3 #define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */
4
5 /* option bits for ccp_options.mppe */
6 #define MPPE_OPT_40 0x01 /* 40 bit */
7 #define MPPE_OPT_128 0x02 /* 128 bit */
8 #define MPPE_OPT_STATEFUL 0x04 /* stateful mode */
9 /* unsupported opts */
10 #define MPPE_OPT_56 0x08 /* 56 bit */
11 #define MPPE_OPT_MPPC 0x10 /* MPPC compression */
12 #define MPPE_OPT_D 0x20 /* Unknown */
13 #define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
14 #define MPPE_OPT_UNKNOWN 0x40 /* Bits !defined in RFC 3078 were set */
15
16 /*
17 * This is not nice ... the alternative is a bitfield struct though.
18 * And unfortunately, we cannot share the same bits for the option
19 * names above since C and H are the same bit. We could do a u_int32
20 * but then we have to do a htonl() all the time and/or we still need
21 * to know which octet is which.
22 */
23 #define MPPE_C_BIT 0x01 /* MPPC */
24 #define MPPE_D_BIT 0x10 /* Obsolete, usage unknown */
25 #define MPPE_L_BIT 0x20 /* 40-bit */
26 #define MPPE_S_BIT 0x40 /* 128-bit */
27 #define MPPE_M_BIT 0x80 /* 56-bit, not supported */
28 #define MPPE_H_BIT 0x01 /* Stateless (in a different byte) */
29
30 /* Does not include H bit; used for least significant octet only. */
31 #define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
32
33 /* Build a CI from mppe opts (see RFC 3078) */
34 #define MPPE_OPTS_TO_CI(opts, ci) \
35 do { \
36 u_char *ptr = ci; /* u_char[4] */ \
37 \
38 /* H bit */ \
39 if (opts & MPPE_OPT_STATEFUL) \
40 *ptr++ = 0x0; \
41 else \
42 *ptr++ = MPPE_H_BIT; \
43 *ptr++ = 0; \
44 *ptr++ = 0; \
45 \
46 /* S,L bits */ \
47 *ptr = 0; \
48 if (opts & MPPE_OPT_128) \
49 *ptr |= MPPE_S_BIT; \
50 if (opts & MPPE_OPT_40) \
51 *ptr |= MPPE_L_BIT; \
52 /* M,D,C bits not supported */ \
53 } while (/* CONSTCOND */ 0)
54
55 /* The reverse of the above */
56 #define MPPE_CI_TO_OPTS(ci, opts) \
57 do { \
58 u_char *ptr = ci; /* u_char[4] */ \
59 \
60 opts = 0; \
61 \
62 /* H bit */ \
63 if (!(ptr[0] & MPPE_H_BIT)) \
64 opts |= MPPE_OPT_STATEFUL; \
65 \
66 /* S,L bits */ \
67 if (ptr[3] & MPPE_S_BIT) \
68 opts |= MPPE_OPT_128; \
69 if (ptr[3] & MPPE_L_BIT) \
70 opts |= MPPE_OPT_40; \
71 \
72 /* M,D,C bits */ \
73 if (ptr[3] & MPPE_M_BIT) \
74 opts |= MPPE_OPT_56; \
75 if (ptr[3] & MPPE_D_BIT) \
76 opts |= MPPE_OPT_D; \
77 if (ptr[3] & MPPE_C_BIT) \
78 opts |= MPPE_OPT_MPPC; \
79 \
80 /* Other bits */ \
81 if (ptr[0] & ~MPPE_H_BIT) \
82 opts |= MPPE_OPT_UNKNOWN; \
83 if (ptr[1] || ptr[2]) \
84 opts |= MPPE_OPT_UNKNOWN; \
85 if (ptr[3] & ~MPPE_ALL_BITS) \
86 opts |= MPPE_OPT_UNKNOWN; \
87 } while (/* CONSTCOND */ 0)