ipv6subnets.c

   1 #include "cll1-0.6.2.h"
   2
   3 /* ====== iptables indexes are used to reduce complexity to log(N) ===== */
   4
   5 char *very_ugly_ipv6_code(char *inip, int bitmask, int format_as_chainname)
   6 {
   7  int colon=0, n, h;
   8  char *ip,*outip,*outptr,*fmt;
   9
  10  duplicate(inip,ip);
  11  /* debug printf("(%s,%d) -> ",ip,bitmask); */
  12
  13  if(ip && *ip && bitmask>=0 && bitmask<=64)
  14  {
  15   string(outip,strlen(ip)+10); /* assertion: 10>strlen("_%d_%d") */
  16  }
  17  else
  18  {
  19   /* should never exit here */
  20   return "undefined";
  21  }
  22  outptr=outip;
  23  while(ip && *ip)
  24  {
  25   if(*ip==':')
  26   {
  27    if(colon<(bitmask/16-1))
  28    {
  29     if(format_as_chainname)
  30     {
  31      *outptr='_';
  32     }
  33     else
  34     {
  35      *outptr=':';
  36     }
  37     outptr++;
  38     colon++;
  39    }
  40    else
  41    {
  42     char *cutcolon=strchr(ip+1,':');
  43     if(cutcolon)
  44     {
  45      *cutcolon = '\0';
  46     }
  47
  48     if(format_as_chainname)
  49     {
  50      fmt = "_%x_%d";
  51     }
  52     else
  53     {
  54      fmt = ":%x";
  55     }
  56
  57     if(bitmask%16)
  58     {
  59      sscanf(ip+1, "%x", &h);
  60 /*    printf("[debug - %s scanned hexa as %x]\n",ip+1,h);*/
  61      n = h-h%(1<<(16-bitmask%16));
  62     }
  63     else
  64     {
  65      n = 0;
  66     }
  67
  68 /*  printf("%d/%d => [_%d_%d]\n",h,bitmask,n,bitmask); */
  69     sprintf(outptr,fmt,n,bitmask);
  70     if(!format_as_chainname)
  71     {
  72      strcat(outip,"::");  /* ahem :-) */
  73     }
  74     /* debug printf("[%s]\n",outip); */
  75     return outip;
  76    }
  77   }
  78   else
  79   {
  80    *outptr=*ip;
  81    outptr++;
  82   }
  83   ip++;
  84  }
  85  /*should never exit here*/
  86  *outptr='\0';
  87  return outip;
  88 }
  89
  90 char *index6_id(char *ip,int bitmask)
  91 {
  92  return very_ugly_ipv6_code(ip,bitmask,1);
  93 }
  94
  95 char *subnet6_id(char *ip,int bitmask)
  96 {
  97  return very_ugly_ipv6_code(ip,bitmask,0);
  98 }