system_ip_blocking_form_validate($form, &$form_state)modules/system/system.admin.inc, line 1448
<?php
function system_ip_blocking_form_validate($form, &$form_state) {
$ip = trim($form_state['values']['ip']);
if (db_query("SELECT * FROM {blocked_ips} WHERE ip = :ip", array(':ip' => $ip))->fetchField()) {
form_set_error('ip', t('This IP address is already blocked.'));
}
elseif ($ip == ip_address()) {
form_set_error('ip', t('You may not block your own IP address.'));
}
elseif (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_RES_RANGE) == FALSE) {
form_set_error('ip', t('Enter a valid IP address.'));
}
}
?>