Circular and Multi-Master Replication tools

I am trying to find out the solution/tools of multi-master replication (4 mysql nodes) when one node goes offline then it should not effected the replication but when it back be online then all replication should work properly.
Please let me know if any tools for above situation.

Thanks

Hi,

Have you heard about PXC (Percona XtraDB Cluster)? I would suggest you to read about it. It might get fulfill your requirement.
http://www.percona.com/doc/percona-xtradb-cluster/5.5/