ipv4subnets.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_ipv4_code(char *inip, int bitmask, int format_as_chainname)
   6 {
   7  int dot=0, n;
   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<=32)
  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(dot<(bitmask/8-1))
  28    {
  29     if(format_as_chainname)
  30     {
  31      *outptr='_';
  32     }
  33     else
  34     {
  35      *outptr='.';
  36     }
  37     outptr++;
  38     dot++;
  39    }
  40    else
  41    {
  42     char *cutdot=strchr(ip+1,'.'); /*for bitmask<24*/
  43     if(cutdot)
  44     {
  45      *cutdot = '\0';
  46     }
  47
  48     if(format_as_chainname)
  49     {
  50      fmt = "_%d_%d";
  51     }
  52     else
  53     {
  54      fmt = ".%d";
  55     }
  56
  57     if(bitmask%8)
  58     {
  59      n = atoi(ip+1)-atoi(ip+1)%(1<<(8-bitmask%8));
  60     }
  61     else
  62     {
  63      n = 0;
  64     }
  65
  66     /*debug  printf("%d/%d => [_%d_%d]\n",atoi(ip+1),bitmask,n,bitmask); */
  67     sprintf(outptr,fmt,n,bitmask);
  68     if(!format_as_chainname)
  69     {
  70      while(bitmask<24)
  71      {
  72       strcat(outip,".0");
  73       bitmask+=8;
  74      }
  75     }
  76     /* debug printf("[%s]\n",outip); */
  77     return outip;
  78    }
  79   }
  80   else
  81   {
  82    *outptr=*ip;
  83    outptr++;
  84   }
  85   ip++;
  86  }
  87  /*should never exit here*/
  88  *outptr='\0';
  89  return outip;
  90 }
  91
  92 char *index_id(char *ip, int bitmask)
  93 {
  94  return very_ugly_ipv4_code(ip,bitmask,1);
  95 }
  96
  97 char *subnet_id(char *ip, int bitmask)
  98 {
  99  return very_ugly_ipv4_code(ip,bitmask,0);
 100 }