lib/dnet_ntop.c

   1 #include <errno.h>
   2 #include <string.h>
   3 #include <sys/types.h>
   4 #include <netinet/in.h>
   5
   6 #include "utils.h"
   7
   8 static __inline__ u_int16_t dn_ntohs(u_int16_t addr)
   9 {
  10         union {
  11                 u_int8_t byte[2];
  12                 u_int16_t word;
  13         } u;
  14
  15         u.word = addr;
  16         return ((u_int16_t)u.byte[0]) | (((u_int16_t)u.byte[1]) << 8);
  17 }
  18
  19 static __inline__ int do_digit(char *str, u_int16_t *addr, u_int16_t scale, size_t *pos, size_t len, int *started)
  20 {
  21         u_int16_t tmp = *addr / scale;
  22
  23         if (*pos == len)
  24                 return 1;
  25
  26         if (((tmp) > 0) || *started || (scale == 1)) {
  27                 *str = tmp + '0';
  28                 *started = 1;
  29                 (*pos)++;
  30                 *addr -= (tmp * scale);
  31         }
  32
  33         return 0;
  34 }
  35
  36
  37 static const char *dnet_ntop1(const struct dn_naddr *dna, char *str, size_t len)
  38 {
  39         u_int16_t addr, area;
  40         size_t pos = 0;
  41         int started = 0;
  42
  43         memcpy(&addr, dna->a_addr, sizeof(addr));
  44         addr = dn_ntohs(addr);
  45         area = addr >> 10;
  46
  47         if (dna->a_len != 2)
  48                 return NULL;
  49
  50         addr &= 0x03ff;
  51
  52         if (len == 0)
  53                 return str;
  54
  55         if (do_digit(str + pos, &area, 10, &pos, len, &started))
  56                 return str;
  57
  58         if (do_digit(str + pos, &area, 1, &pos, len, &started))
  59                 return str;
  60
  61         if (pos == len)
  62                 return str;
  63
  64         *(str + pos) = '.';
  65         pos++;
  66         started = 0;
  67
  68         if (do_digit(str + pos, &addr, 1000, &pos, len, &started))
  69                 return str;
  70
  71         if (do_digit(str + pos, &addr, 100, &pos, len, &started))
  72                 return str;
  73
  74         if (do_digit(str + pos, &addr, 10, &pos, len, &started))
  75                 return str;
  76
  77         if (do_digit(str + pos, &addr, 1, &pos, len, &started))
  78                 return str;
  79
  80         if (pos == len)
  81                 return str;
  82
  83         *(str + pos) = 0;
  84
  85         return str;
  86 }
  87
  88
  89 const char *dnet_ntop(int af, const void *addr, char *str, size_t len)
  90 {
  91         switch(af) {
  92                 case AF_DECnet:
  93                         errno = 0;
  94                         return dnet_ntop1((struct dn_naddr *)addr, str, len);
  95                 default:
  96                         errno = EAFNOSUPPORT;
  97         }
  98
  99         return NULL;
 100 }
 101
 102