ipv4subnets.c

   1 #include "cll1-0.6.2.h"
   2
   3 /* ====== iptables indexes are used to reduce complexity to log8(N) ===== */
   4
   5 char *very_ugly_ipv4_code(char *inip, int bitmask, int format_as_chainname)
   6 {
   7  /* warning: this function was debugged only for bitmask values 20,24,28 !!!*/
   8  int dot=0, n;
   9  char *ip,*outip,*outptr,*fmt;
  10
  11  duplicate(inip,ip);
  12  /* debug printf("(%s,%d) -> ",ip,bitmask); */
  13
  14  if(ip && *ip && bitmask>=0 && bitmask<=32)
  15  {
  16   string(outip,strlen(ip)+10); /*fuck unicode? assertion: 10>strlen("_%d_%d") */
  17  }
  18  else
  19  {
  20   /* should never exit here */
  21   return "undefined";
  22  }
  23  outptr=outip;
  24  while(ip && *ip)
  25  {
  26   if(*ip=='.')
  27   {
  28    if(dot<(bitmask/8-1))
  29    {
  30     if(format_as_chainname)
  31     {
  32      *outptr='_';
  33     }
  34     else
  35     {
  36      *outptr='.';
  37     }
  38     outptr++;
  39     dot++;
  40    }
  41    else
  42    {
  43     char *cutdot=strchr(ip+1,'.'); /*for bitmask<24*/
  44     if(cutdot)
  45     {
  46      *cutdot = '\0';
  47     }
  48
  49     if(format_as_chainname)
  50     {
  51      fmt = "_%d_%d";
  52     }
  53     else
  54     {
  55      fmt = ".%d";
  56     }
  57
  58     if(bitmask%8)
  59     {
  60      n = atoi(ip+1)-atoi(ip+1)%(1<<(8-bitmask%8));
  61     }
  62     else
  63     {
  64      n = 0;
  65     }
  66
  67     /*debug  printf("%d/%d => [_%d_%d]\n",atoi(ip+1),bitmask,n,bitmask); */
  68     sprintf(outptr,fmt,n,bitmask);
  69     if(!format_as_chainname)
  70     {
  71      while(bitmask<24)
  72      {
  73       strcat(outip,".0");
  74       bitmask+=8;
  75      }
  76     }
  77     /* debug printf("[%s]\n",outip); */
  78     return outip;
  79    }
  80   }
  81   else
  82   {
  83    *outptr=*ip;
  84    outptr++;
  85   }
  86   ip++;
  87  }
  88  /*should never exit here*/
  89  *outptr='\0';
  90  return outip;
  91 }
  92
  93 char *index_id(char *ip,int bitmask)
  94 {
  95  return very_ugly_ipv4_code(ip,bitmask,1);
  96 }
  97
  98 char *subnet_id(char *ip,int bitmask)
  99 {
 100  return very_ugly_ipv4_code(ip,bitmask,0);
 101 }