While netmap implements virtio-net header, it does not implement
receive_raw(). Instead of implementing receive_raw for netmap, add
virtio-net headers in the common code and use receive_iov()/receive()
instead. This also fixes the buffer size for the virtio-net header.
Fixes: fbbdbddec0 ("tap: allow extended virtio header with hash info")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>