MySQL IPv4 Validation implementation

Question

Hello guys it is my first post

I am struggling here for the past two days in implementing validation for ipv4 address.... The problem is that the validation should be performed on database level and this makes it difficult for noob like me

So I have to make :

1. Validation of ipv4 address
2. If the prefix somewhere in the ip is 0 I have to remove it (example : 123.013.221.011 should become 123.13.221.11)

What I have so far in a trigger:

This is not working as it is supposed to, so I am asking you guys for help...thanks !!!

DELIMITER $$
CREATE TRIGGER validation_trigger BEFORE INSERT ON setting_parameters
FOR EACH ROW 
BEGIN 
-- PROXY RULES --
   IF(NEW.parameter_name LIKE '%proxy%') = true THEN 
     IF(INET_ATON(NEW.parameter_value)<INET_ATON('255.255.255.255'))=true THEN 
        IF(NEW.parameter_name LIKE '0%') = true THEN 
           SET NEW.parameter_value = SUBSTR(NEW.parameter_value,2);
        ELSE 
           SIGNAL SQLSTATE '12345'
           SET MESSAGE_TEXT = 'Wrong PROXY parameter values !';
        END IF;
     END IF;
   END IF;

Answer 1

Here is a suggestion. Consider implementing this functionality as a User Defined Functions (or UDF). This will allow you to write code in either c or c++ rather than SQL.

Alternatively, You can use REGEXP support in MySQL.

This is a solution for Part 1 of your question:

This example is for validating an IPV4 address using REGEXP

SELECT '123.1.2.3'
REGEXP '^([1-9]|[1-9][0-9]|1[013-9][0-9]|12[0-689]|2[0-4][1-9]|25[0-4])\.(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){2}([1-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][1-9]|25[0-4])$'
;

SQL Fiddle Link

(Note: I have never used triggers myself. Hence cannot give you ready-to-use code. But you can use this example to make a trigger out of it)

I think solution for part 2 is a simple find-and-replace. Here again a REGEXP can be used to match all the patterns of 0, 00, .0, .00 and replace with a . (or nothing, if beginning of string)

Update 2:

Here is an SQL example to remove leading zeros. I did not have to use REGEXP here since CAST() did the magic!

SELECT ip, 
    CONCAT_WS('.',CAST(SUBSTRING_INDEX(ip,'.',1) as UNSIGNED), 
    CAST(SUBSTRING_INDEX(SUBSTRING_INDEX(ip,'.',2),'.',-1) as UNSIGNED), 
    CAST(SUBSTRING_INDEX(SUBSTRING_INDEX(ip,'.',-2),'.',1) as UNSIGNED), 
    CAST(SUBSTRING_INDEX(ip,'.',-1) as UNSIGNED))  as Converted_IP
FROM ip_addr;

If ip_addr is a table with a column named ip and values like this

-------------    
IP
-------------
127.0.0.1
001.02.0.123
1.23.123.000
-------------

The SQL will Output:

-----------------------------
IP              CONVERTED_IP
-----------------------------
127.0.0.1       127.0.0.1
001.02.0.123    1.2.0.123
1.23.123.000    1.23.123.0
-----------------------------

SQL Fiddle Link

Update 3:

I think this solution by Michael Berkowski is awesome

Answer 2

There are pre-implemented functions to check the validity of an ip address. please check https://dev.mysql.com/doc/refman/8.0/en/miscellaneous-functions.html

Simply call IS_IPV4()