BGP make client (default) announcement depend on ibgp/upstream peers being "up"

[Patrick Schaaf]

Hi,

new bird / BGP user here, please bear with me :)

Consider a scenario with a bird box acting as (one of several
possible) gateway for a set of clients, while having an iBGP and/or
upstream BGP connection where the "real routes" come from.

Towards the client(s) a default route should be announced.

Is it possible to make the client default route announcement depend on
at least one of the upstream peers (iBGP, real upstream) being "up"
and having sent us all its routes? Or, even more ideally, one of them
being up, having sent all its routes, _and_ bird having gotten around
to installing them all in the kernel (data plane)?

Conversely, if for any reason no more upstream peers are up, kernel
routes are withdrawm (shutdown), withdraw that default announce to the
clients?

Is this possible? (using bird 2.0.2)

Is there a different approach to make sure the clients won't be fooled
into sending us data plane traffic already while we're not ready for
it yet?

best regards
  Patrick