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drivers/net/ppp_mppe.h 4.01 KB
b3f9b92a6   Matt Domsch   [PPP]: add PPP MP...
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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)