linux/drivers/net/ppp/ppp_mppe.h
<<
>>
Prefs
   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