declare
 i varchar2(50);
 n varchar2(50);
 m varchar2(50);
 cv_ipseparator CONSTANT VARCHAR2(1) := '.'; 
FUNCTION fn_IpIsMask(p_MaskIp VARCHAR2, p_Mask VARCHAR2, p_IpNum VARCHAR2) RETURN NUMBER
  IS
    vr_returnvalue NUMBER;
  vr_Numip NUMBER;
  vr_NumMaskip NUMBER;
  vr_NumMask NUMBER; 
  vr_NumReturn NUMBER; 
FUNCTION Fn_IPtoNum(p_ip IN VARCHAR2) RETURN NUMBER 
 IS
   vr_IpNumber VARCHAR2(255);
   vr_IpReturnNumber NUMBER;
   vr_dec1 VARCHAR2(255);
   vr_dec2 VARCHAR2(255);
   vr_dec3 VARCHAR2(255);
   vr_dec4 VARCHAR2(255);
 BEGIN
 BEGIN
   vr_ipNumber := p_ip ;
   vr_dec1 := SUBSTR(vr_ipNumber, 1, INSTR(vr_ipNumber, cv_ipseparator )-1);
   vr_ipNumber := SUBSTR(vr_ipNumber , INSTR(vr_ipNumber, cv_ipseparator )+1); 
   vr_dec2 := SUBSTR(vr_ipNumber, 1, INSTR(vr_ipNumber, cv_ipseparator )-1);
   vr_ipNumber := SUBSTR(vr_ipNumber , INSTR(vr_ipNumber, cv_ipseparator )+1); 
   vr_dec3 := SUBSTR(vr_ipNumber, 1, INSTR(vr_ipNumber, cv_ipseparator )-1);
   vr_ipNumber := SUBSTR(vr_ipNumber , INSTR(vr_ipNumber, cv_ipseparator )+1)||'.'; 
   vr_dec4 := SUBSTR(vr_ipNumber, 1, INSTR(vr_ipNumber, cv_ipseparator )-1);
 --   
   IF TO_NUMBER(vr_dec1)>255 THEN 
     vr_dec1:='0';
   END IF;
   IF TO_NUMBER(vr_dec2)>255 THEN 
     vr_dec2:='0';
   END IF;
   IF TO_NUMBER(vr_dec3)>255 THEN 
     vr_dec3:='0';
   END IF;
   IF TO_NUMBER(vr_dec4)>255 THEN 
     vr_dec4:='0';
   END IF;
   vr_IpReturnNumber := 
     TO_NUMBER(vr_dec4)
   + TO_NUMBER(vr_dec3) * 256
   + TO_NUMBER(vr_dec2) * 256* 256
   + TO_NUMBER(vr_dec1) * 256 * 256 * 256;
  EXCEPTION 
    WHEN OTHERS THEN RAISE_APPLICATION_ERROR('Fn_IPtoNum '||SQLERRM ,0 );	
  END; 
  RETURN vr_ipReturnNumber;
  END Fn_IpToNum;   
  BEGIN
  BEGIN     
    IF INSTR(p_MaskIp, '.') = 0 THEN    
      vr_NumMaskip := TO_NUMBER(p_MaskIp);
  ELSE   
      vr_NumMaskip := fn_IpToNum(p_MaskIp);
  END IF;
    IF INSTR(p_IpNum, '.') = 0 THEN    
      vr_Numip := TO_NUMBER(p_IpNum);
  ELSE   
      vr_Numip := fn_IpToNum(p_IpNum);
  END IF;
    IF INSTR(p_Mask, '.') = 0 THEN    
    IF vr_NumMask<33 THEN
         vr_NumMask := TO_NUMBER(p_Mask);
    ELSE     
         vr_NumMask := fn_IpToNum(p_Mask);
    END IF; 
  ELSE
    vr_NumMask := fn_IpToNum(p_Mask);
  -- здесь надо доработать  
  END IF;  
  SELECT BITAND(vr_NumMask, vr_NumIp) 
    INTO vr_NumReturn 
    FROM dual;
  vr_returnvalue := 0;   
   SELECT DECODE(vr_NumReturn, vr_NumMaskip, 1 , 0) 
    INTO vr_returnvalue
    FROM 
    dual ;    
    RETURN vr_returnvalue;
  EXCEPTION 
    WHEN OTHERS THEN RAISE_APPLICATION_ERROR('fn_IpIsMask '||SQLERRM ,0 );	
  END;
  END fn_IpIsMask; 
begin
 dbms_output.put_line(to_char(fn_IpIsMask('123.123.123.0','255.255.255.0','123.123.123.8'))); 
end;

begin
 dbms_output.put_line(to_char(fn_IpIsMask('123.123.123.0','255.255.0.0','123.123.123.8'))); 
end;

begin
 dbms_output.put_line(to_char(fn_IpIsMask('123.123.0.0','255.255.0.0','123.123.123.8'))); 
end;