xref: /openbmc/linux/drivers/net/ppp/ppp_mppe.h (revision f3539c12)
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