Galera Mariadb Multi-Master Replication
The performance is going to be atrocious with your setup, especially in writes because every write has to be acknowledged by at least one remote node. You will also get an astronomical number of deadlocks.
If you need geo-replicated synchronous redundancy, you would be batter off with with DRBD for block level replication. Performance will still be terrible on commit latency but not as terrible as with Galera.
You need to rethink your requirements and your approach to fulfilling them.