• Eric Dumazet's avatar
    tcp: reflect SYN queue_mapping into SYNACK packets · fff32699
    Eric Dumazet authored
    While testing how linux behaves on SYNFLOOD attack on multiqueue device
    (ixgbe), I found that SYNACK messages were dropped at Qdisc level
    because we send them all on a single queue.
    
    Obvious choice is to reflect incoming SYN packet @queue_mapping to
    SYNACK packet.
    
    Under stress, my machine could only send 25.000 SYNACK per second (for
    200.000 incoming SYN per second). NIC : ixgbe with 16 rx/tx queues.
    
    After patch, not a single SYNACK is dropped.
    Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
    Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>
    Cc: Jesper Dangaard Brouer <brouer@redhat.com>
    Cc: Neal Cardwell <ncardwell@google.com>
    Cc: Tom Herbert <therbert@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    fff32699
tcp_ipv4.c 67.1 KB