The assumptions on which this test was based were violated by the
introduction of fast datapath. A new rule is required to block fast
datapath traffic, to ensure that sleeve is selected for forwarding; the
rules must also be moved from the FORWARD chain to INPUT as the router
now runs in the host netns (NB we use INPUT instead of OUTPUT as the
latter results in sleeve receiving an 'operation not permitted' udpv4
write error when it tries to send a packet that is too big, rather than
the packet just being silently dropped as required)
Marc CARRE