wp-includes/rest-api.php:1517Determines if an IP address is valid.
$ipstringstring|falsefunction rest_is_ip_address( $ip ) { $ipv4_pattern = '/^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/'; if ( ! preg_match( $ipv4_pattern, $ip ) && ! WpOrg\Requests\Ipv6::check_ipv6( $ip ) ) { return false; } return $ip;}Introduced in 4.7.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rest-api.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.