[Click] Accessing the ingress interface of a packet

[Philip Prindeville]

(Forgive the newbie questions... I'm having to learn Click in a hurry as I ramp up on a project.)

Is there a built-in element that returns the ingress interface of a packet?

I'm trying to write an elementclass in Click that modifies a packet and then sends it back out the same interface it came in on, but don't want to have one instance of it per-interface that it is used on.

Thanks.

-Philip