It does not make sense to queue retransmitted packets if the
original packet is still in some queue of this host. So add
a check to xdst_queue_output() and drop the packet if the
original packet is not yet sent.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Eric Dumazet <edumazet@google.com>