Representing IPv4/IPv6 addresses in Oracle

In Oracle, what is the appropriate data type or technique for representing network addresses, which addresses may be IPv4 or IPv6?

Background: I'm converting a table recording network activity, built using the PostgreSQL inet data type to hold both v4 and v6 addresses in the same table.

No row contains both v4 and v6 addresses, however. (That is, a record is either from a machine's v4 stack, or a machine's v6 stack.)