Same as for udp4, let BPF program override the socket lookup result, by
selecting a receiving socket of its choice or failing the lookup, if no
connected UDP socket matched packet 4-tuple.
Suggested-by: NMarek Majkowski <marek@cloudflare.com>
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200717103536.397595-11-jakub@cloudflare.com