When using the view plugin, filtered and unfiltered server blocks can
share the same zone and port. The zone overlap validation rejected this
configuration when the unfiltered block was not declared last, because
filtered configs treated an already-registered zone as an error.
Skip the 'already defined' check for configs that have filter functions,
since they are expected to coexist with an unfiltered catch-all block on
the same zone/port.
Fixes#7733
Signed-off-by: umut-polat <52835619+umut-polat@users.noreply.github.com>
* introduce new interface "dnsserver.Viewer", that allows a plugin implementing it to decide if a query should be routed into its server block.
* add new plugin "view", that uses the new interface to enable a user to define expression based conditions that must be met for a query to be routed to its server block.
Signed-off-by: Chris O'Haver <cohaver@infoblox.com>
