Allow DNSAction.Allow action for DynBlocks

[MiniPierre]

• Program: dnsdist
• Issue type: Feature request

Short description

DynBlocks only allow DNSAction.Drop, DNSAction.NoOp, DNSAction.NXDomain, DNSAction.Refused, DNSAction.Truncate and DNSAction.NoRecurse at the moment. Allowing the DNSAction.Allow action would be an interesting feature for testing purposes

Usecase

We are currently working with XDP filter and would like to perform some tests in order to set our rules threshold correctly. The idea would be to set a threshold to trigger XDP action but in a non-blocking way so that we can perform with real data. BPFFilter::MatchAction include the PASS Action, but as DynBlocks do not allow the DNSAction.Allow action, it is not possible to set it up.

[rgacogne]

That does make complete sense to me! It might take me a bit of time before I can actually implement that myself, but I would gladly review a pull request implementing that in the meantime ;-)