chiark - git - mdw - secnet/blob - transform-common.h

   1
   2 #ifndef TRANSFORM_COMMON_H
   3 #define TRANSFORM_COMMON_H
   4
   5 #include "magic.h"
   6
   7 #define KEYED_CHECK do{                         \
   8         if (!ti->keyed) {                       \
   9             *errmsg="transform unkeyed";        \
  10             return 1;                           \
  11         }                                       \
  12     }while(0)
  13
  14 #define RECVBITMAP_SIZE 32
  15 typedef uint32_t recvbitmap_type;
  16
  17 #define SEQNUM_CHECK(seqnum, p) do{                             \
  18         uint32_t skew=seqnum-ti->lastrecvseq;                   \
  19         if (skew<0x8fffffff) {                                  \
  20             /* Ok */                                            \
  21             ti->lastrecvseq=seqnum;                             \
  22             if (skew < RECVBITMAP_SIZE)                         \
  23                 ti->recvbitmap <<= skew;                        \
  24             else                                                \
  25                 ti->recvbitmap=0;                               \
  26             skew=0;                                             \
  27         } else if ((0-skew)<(p)->max_seq_skew) {                \
  28             /* Ok */                                            \
  29         } else {                                                \
  30             /* Too much skew */                                 \
  31             *errmsg="seqnum: too much skew";                    \
  32             return 2;                                           \
  33         }                                                       \
  34         if ((p)->dedupe) {                                      \
  35             recvbitmap_type recvbit=(uint32_t)1 << skew;        \
  36             if (ti->recvbitmap & recvbit) {                     \
  37                 *errmsg="seqnum: duplicate";                    \
  38                 return 2;                                       \
  39             }                                                   \
  40             ti->recvbitmap |= recvbit;                          \
  41         }                                                       \
  42     }while(0)
  43
  44 #define SEQNUM_KEYED_FIELDS                                             \
  45     uint32_t sendseq;                                                   \
  46     uint32_t lastrecvseq;                                               \
  47     recvbitmap_type recvbitmap; /* 1<<0 is lastrecvseq (i.e., most recent) */ \
  48     bool_t keyed
  49
  50 #define SEQNUM_KEYED_INIT(initlastrecvseq,initsendseq)  \
  51     (ti->lastrecvseq=(initlastrecvseq),                 \
  52      ti->sendseq=(initsendseq),                         \
  53      ti->recvbitmap=0,                                  \
  54      ti->keyed=True)
  55
  56 #define TRANSFORM_VALID                         \
  57     static bool_t transform_valid(void *sst)    \
  58     {                                           \
  59         struct transform_inst *ti=sst;          \
  60                                                 \
  61         return ti->keyed;                       \
  62     }
  63
  64 #define TRANSFORM_DESTROY                               \
  65     static void transform_destroy(void *sst)            \
  66     {                                                   \
  67         struct transform_inst *st=sst;                  \
  68                                                         \
  69         FILLZERO(*st); /* Destroy key material */       \
  70         free(st);                                       \
  71     }
  72
  73 #define SET_CAPAB_TRANSFORMNUM(def) do{                                 \
  74         st->ops.capab_transformnum=dict_read_number(dict, "capab-num",  \
  75                                      False, "transform", loc, (def));   \
  76         if (st->ops.capab_transformnum > CAPAB_TRANSFORMNUM_MAX)        \
  77             cfgfatal(loc,"transform","capab-num out of range 0..%d\n",  \
  78                      CAPAB_TRANSFORMNUM_MAX);                           \
  79     }while(0)
  80
  81 #define TRANSFORM_CREATE_CORE                           \
  82         struct transform_inst *ti;                      \
  83         NEW(ti);                                        \
  84         /* mlock XXX */                                 \
  85         ti->ops.st=ti;                                  \
  86         ti->ops.setkey=transform_setkey;                \
  87         ti->ops.valid=transform_valid;                  \
  88         ti->ops.delkey=transform_delkey;                \
  89         ti->ops.forwards=transform_forward;             \
  90         ti->ops.reverse=transform_reverse;              \
  91         ti->ops.destroy=transform_destroy;              \
  92         ti->keyed=False;
  93
  94 #define SEQNUM_PARAMS_FIELDS                    \
  95     uint32_t max_seq_skew;                      \
  96     bool_t dedupe;
  97
  98 #define SEQNUM_PARAMS_INIT(dict,p,desc,loc)                             \
  99     (p)->max_seq_skew=dict_read_number((dict), "max-sequence-skew",     \
 100                                         False, (desc), (loc), 10);      \
 101     bool_t can_dedupe=(p)->max_seq_skew < RECVBITMAP_SIZE;              \
 102     (p)->dedupe=dict_read_bool((dict), "dedupe",                        \
 103                                False,(desc),(loc), can_dedupe);         \
 104     if ((p)->dedupe && !can_dedupe)                                     \
 105         cfgfatal(loc,"transform",                                       \
 106                  "cannot dedupe with max-sequence-skew>=32");           \
 107     else (void)0
 108
 109 #endif /*TRANSFORM_COMMON_H*/