SKB_DROP_REASON_TCP_OLD_DATA is used for the case that end_seq of skb
less than the left edges of receive window. (Maybe there is a better
name?)
Reviewed-by: Mengen Sun <mengensun@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>