samples/bpf: xdp_redirect load XDP dummy prog on TX device
For supporting XDP_REDIRECT, a device driver must (obviously) implement the "TX" function ndo_xdp_xmit(). An additional requirement is you cannot TX out a device, unless it also have a xdp bpf program attached. This dependency is caused by the driver code need to setup XDP resources before it can ndo_xdp_xmit. Update bpf samples xdp_redirect and xdp_redirect_map to automatically attach a dummy XDP program to the configured ifindex_out device. Use the XDP flag XDP_FLAGS_UPDATE_IF_NOEXIST on the dummy load, to avoid overriding an existing XDP prog on the device. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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