IP address stored as decimal - PL/SQL to display as dotted quad - oracle

Question

We have an Oracle database that contains IP addresses stored as decimal integers - this is incredibly painful when manipulating the data by hand instead of via the web interface, yet hand manipulation is really handy as the network guys continually ask us to do strange things that the web interface authors did not anticipate.
Could someone provide me with the PL/SQL or other method to display these decimal IPs as dotted decimal i.e. 123.123.123.123 format?
I.e. I'd like to be able to run a query such as :
select hostname, inttoip(ip_address) from host;
and have the inttoip() procedure display ip_address as 203.30.237.2 instead of as 3407801602.
Ideally I'd like a procedure which provides the inverse function too, e.g.
insert into host (hostname,ip_address) values ('some-hostname', iptoint('203.30.237.2'));
I have perl to do this, but my PL/SQL/Oracle knowledge is not good enough to port it into PL/SQL.
Alternatively a way to run the perl as the procedural language within the oracle context analogous to the following in postgres:
CREATE FUNCTION perl_func (integer) RETURNS integer AS $$
<some perl>
$$ LANGUAGE plperl;
Would be great - if possible - probably even better as I could then do lots of procedural stuff within Oracle in a language I am familiar with.

Answer 1

This is the function you need:
create or replace
function inttoip(ip_address integer) return varchar2
deterministic
is
begin
return to_char(mod(trunc(ip_address/256/256/256),256))
||'.'||to_char(mod(trunc(ip_address/256/256),256))
||'.'||to_char(mod(trunc(ip_address/256),256))
||'.'||to_char(mod(ip_address,256));
end;
(Comments about making function deterministic and using to_char taken on board - thanks).
In Oracle 11G you could make the formatted IP address a virtual column on the host table:
alter table host
add formatted_ip_address varchar2(15)
generated always as
( to_char(mod(trunc(ip_address/256/256/256),256))
||'.'||to_char(mod(trunc(ip_address/256/256),256))
||'.'||to_char(mod(trunc(ip_address/256),256))
||'.'||to_char(mod(ip_address,256))
) virtual;
This column could then be indexed for queries if required.
Your query becomes:
select hostname, formatted_ip_address from host;

Answer 2

CREATE OR REPLACE
FUNCTION inttoip(ip_address IN INTEGER) RETURN VARCHAR2 IS
v8 VARCHAR2(8);
BEGIN
-- 1. convert the integer into hexadecimal representation
v8 := TO_CHAR(ip_address, 'FMXXXXXXXX');
-- 2. convert each XX portion back into decimal
RETURN to_number(substr(v8,1,2),'XX')
|| '.' || to_number(substr(v8,3,2),'XX')
|| '.' || to_number(substr(v8,5,2),'XX')
|| '.' || to_number(substr(v8,7,2),'XX');
END inttoip;
CREATE OR REPLACE
FUNCTION iptoint(ip_string IN VARCHAR2) RETURN INTEGER IS
d1 INTEGER;
d2 INTEGER;
d3 INTEGER;
q1 VARCHAR2(3);
q2 VARCHAR2(3);
q3 VARCHAR2(3);
q4 VARCHAR2(3);
v8 VARCHAR2(8);
BEGIN
-- 1. parse the input, e.g. '203.30.237.2'
d1 := INSTR(ip_string,'.'); -- first dot
d2 := INSTR(ip_string,'.',1,2); -- second dot
d3 := INSTR(ip_string,'.',1,3); -- third dot
q1 := SUBSTR(ip_string, 1, d1 - 1); -- e.g. '203'
q2 := SUBSTR(ip_string, d1 + 1, d2 - d1 - 1); -- e.g. '30'
q3 := SUBSTR(ip_string, d2 + 1, d3 - d2 - 1); -- e.g. '237'
q4 := SUBSTR(ip_string, d3 + 1); -- e.g. '2'
-- 2. convert to a hexadecimal string
v8 := LPAD(TO_CHAR(TO_NUMBER(q1),'FMXX'),2,'0')
|| LPAD(TO_CHAR(TO_NUMBER(q2),'FMXX'),2,'0')
|| LPAD(TO_CHAR(TO_NUMBER(q3),'FMXX'),2,'0')
|| LPAD(TO_CHAR(TO_NUMBER(q4),'FMXX'),2,'0');
-- 3. convert to a decimal number
RETURN TO_NUMBER(v8, 'FMXXXXXXXX');
END iptoint;

Answer 3

-- INET ATON en INET NTOA and helper function GET TOKEN
CREATE OR REPLACE function inet_ntoa (ip integer) return varchar2
is
ip1 integer;
ip2 integer;
ip3 integer;
ip4 integer;
ipi integer := ip;
begin
ip1 := floor(ipi/power(2,24));
ipi := ipi - (ip1*power(2,24));
ip2 := floor(ipi/power(2,16));
ipi := ipi - (ip2*power(2,16));
ip3 := floor(ipi/power(2,8));
ipi := ipi - (ip3*power(2,8));
ip4 := ipi;
return ip1||'.'||ip2||'.'||ip3||'.'||ip4;
end;
/
CREATE OR REPLACE FUNCTION get_token (the_list VARCHAR2,the_index NUMBER, delim VARCHAR2 := '.') RETURN VARCHAR2
IS
start_pos INTEGER;
end_pos INTEGER;
BEGIN
IF the_index = 1 THEN
start_pos := 1;
ELSE
start_pos := INSTR (the_list, delim, 1, the_index - 1);
IF start_pos = 0 THEN
RETURN NULL;
ELSE
start_pos := start_pos + LENGTH (delim);
END IF;
END IF;
end_pos := INSTR (the_list, delim, start_pos, 1);
IF end_pos = 0 THEN
RETURN SUBSTR (the_list, start_pos);
ELSE
RETURN SUBSTR (the_list, start_pos, end_pos - start_pos);
END IF;
END get_token;
/
CREATE OR REPLACE function inet_aton (ip varchar2) return integer
is
invalid_ip_adres exception;
pragma exception_init(invalid_ip_adres,-6502);
ipi integer;
begin
ipi := get_token(ip,4)
+(get_token(ip,3)*power(2,8))
+(get_token(ip,2)*power(2,16))
+(get_token(ip,1)*power(2,24));
return ipi;
exception
when invalid_ip_adres
then
return null;
end;
/