Since XDP's view of the packet includes the MAC header, moving the start-
of-packet with bpf_xdp_adjust_head needs to also update the offset of the
MAC header (which is relative to skb->head, not to the skb->data that was
changed).
Without this, tcpdump sees packets starting from the old MAC header rather
than the new one, at least in my tests on the loopback device.
Fixes: b5cdae3291 ("net: Generic XDP")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
92dd5452c1