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#define MPPE_PAD 4 /* MPPE growth per frame */
#define MPPE_MAX_KEY_LEN 16 /* largest key length (128-bit) */
/* option bits for ccp_options.mppe */
#define MPPE_OPT_40 0x01 /* 40 bit */
#define MPPE_OPT_128 0x02 /* 128 bit */
#define MPPE_OPT_STATEFUL 0x04 /* stateful mode */
/* unsupported opts */
#define MPPE_OPT_56 0x08 /* 56 bit */
#define MPPE_OPT_MPPC 0x10 /* MPPC compression */
#define MPPE_OPT_D 0x20 /* Unknown */
#define MPPE_OPT_UNSUPPORTED (MPPE_OPT_56|MPPE_OPT_MPPC|MPPE_OPT_D)
#define MPPE_OPT_UNKNOWN 0x40 /* Bits !defined in RFC 3078 were set */
/*
* This is not nice ... the alternative is a bitfield struct though.
* And unfortunately, we cannot share the same bits for the option
* names above since C and H are the same bit. We could do a u_int32
* but then we have to do a htonl() all the time and/or we still need
* to know which octet is which.
*/
#define MPPE_C_BIT 0x01 /* MPPC */
#define MPPE_D_BIT 0x10 /* Obsolete, usage unknown */
#define MPPE_L_BIT 0x20 /* 40-bit */
#define MPPE_S_BIT 0x40 /* 128-bit */
#define MPPE_M_BIT 0x80 /* 56-bit, not supported */
#define MPPE_H_BIT 0x01 /* Stateless (in a different byte) */
/* Does not include H bit; used for least significant octet only. */
#define MPPE_ALL_BITS (MPPE_D_BIT|MPPE_L_BIT|MPPE_S_BIT|MPPE_M_BIT|MPPE_H_BIT)
/* Build a CI from mppe opts (see RFC 3078) */
#define MPPE_OPTS_TO_CI(opts, ci) \
do { \
u_char *ptr = ci; /* u_char[4] */ \
\
/* H bit */ \
if (opts & MPPE_OPT_STATEFUL) \
*ptr++ = 0x0; \
else \
*ptr++ = MPPE_H_BIT; \
*ptr++ = 0; \
*ptr++ = 0; \
\
/* S,L bits */ \
*ptr = 0; \
if (opts & MPPE_OPT_128) \
*ptr |= MPPE_S_BIT; \
if (opts & MPPE_OPT_40) \
*ptr |= MPPE_L_BIT; \
/* M,D,C bits not supported */ \
} while (/* CONSTCOND */ 0)
/* The reverse of the above */
#define MPPE_CI_TO_OPTS(ci, opts) \
do { \
u_char *ptr = ci; /* u_char[4] */ \
\
opts = 0; \
\
/* H bit */ \
if (!(ptr[0] & MPPE_H_BIT)) \
opts |= MPPE_OPT_STATEFUL; \
\
/* S,L bits */ \
if (ptr[3] & MPPE_S_BIT) \
opts |= MPPE_OPT_128; \
if (ptr[3] & MPPE_L_BIT) \
opts |= MPPE_OPT_40; \
\
/* M,D,C bits */ \
if (ptr[3] & MPPE_M_BIT) \
opts |= MPPE_OPT_56; \
if (ptr[3] & MPPE_D_BIT) \
opts |= MPPE_OPT_D; \
if (ptr[3] & MPPE_C_BIT) \
opts |= MPPE_OPT_MPPC; \
\
/* Other bits */ \
if (ptr[0] & ~MPPE_H_BIT) \
opts |= MPPE_OPT_UNKNOWN; \
if (ptr[1] || ptr[2]) \
opts |= MPPE_OPT_UNKNOWN; \
if (ptr[3] & ~MPPE_ALL_BITS) \
opts |= MPPE_OPT_UNKNOWN; \
} while (/* CONSTCOND */ 0)
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