Root/drivers/net/ppp_mppe.h

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

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