SELECT * FROM TABLE WHERE `column1` = 'x' and (`column2` = INET_ATON('1.1.1.1') OR `column3` like '%bla%'...)

$where->add($qb->expr()->eq('column2', $qb->expr()->literal('inet_aton('1.1.1.1'))));

<?php

namespace ApplicationDQL;

use DoctrineORMQueryLexer;

class InetAtonFunction extends DoctrineORMQueryASTFunctionsFunctionNode
{
    public $valueExpression = null;

    /**
     * parse
     *
     * @param DoctrineORMQueryParser $parser
     * @access public
     * @return void
     */
    public function parse(DoctrineORMQueryParser $parser)
    {
        $parser->match(Lexer::T_IDENTIFIER);
        $parser->match(Lexer::T_OPEN_PARENTHESIS);
        $this->valueExpression = $parser->StringPrimary();
        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }

    /**
     * getSql
     *
     * @param DoctrineORMQuerySqlWalker $sqlWalker
     * @access public
     * @return string
     */
    public function getSql(DoctrineORMQuerySqlWalker $sqlWalker)
    {
        return 'INET_ATON('. $this->valueExpression->dispatch($sqlWalker) . ')';
    }
}

<?php
namespace Observer;

//...

class Module implements
    AutoloaderProviderInterface,
    ConfigProviderInterface,
    ServiceProviderInterface
{
//...
    public function onBootstrap($e)
    {

        $application = $e->getParam('application');
        $sm  = $application->getServiceManager();
        $em  = $application->getEventManager();

        $entityManager = $sm->get('doctrine.entitymanager.orm_default');
        $entityManager->getConfiguration()->addCustomStringFunction('inet_aton', 'ApplicationDQLInetAtonFunction');
    }
...

SELECT whatever FROM someting where cloumn = inet_aton(:?)

<?php

namespace MyAppDQL;

use DoctrineORMQueryASTFunctionsFunctionNode;
use DoctrineORMQueryLexer;
use DoctrineORMQuerySqlWalker;

class InetAnon extends FunctionNode
{
    private $arithmeticExpression;

    public function getSql(SqlWalker $sqlWalker)
    {

        return 'INET_ANON(' . $sqlWalker->walkSimpleArithmeticExpression(
            $this->arithmeticExpression
        ) . ')';
    }

    public function parse(DoctrineORMQueryParser $parser)
    {

        $lexer = $parser->getLexer();

        $parser->match(Lexer::T_IDENTIFIER);
        $parser->match(Lexer::T_OPEN_PARENTHESIS);

        $this->arithmeticExpression = $parser->SimpleArithmeticExpression();

        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }
}

$config = new DoctrineORMConfiguration();

$config->addCustomNumericFunction('INET_ANON', 'MyAppDQLInetAnon');

doctrine:
    dbal:
        driver:   "%database_driver%"
        host:     "%database_host%"
        port:     "%database_port%"
        dbname:   "%database_name%"
        user:     "%database_user%"
        password: "%database_password%"

    orm:
        auto_generate_proxy_classes: "%kernel.debug%"
        auto_mapping: true
        dql:
            string_functions:
                inet_aton: homemyBundlemyFolderContaintClassInetAton