• Sowmini Varadhan's avatar
    net/rds: RDS-TCP: Always create a new rds_sock for an incoming connection. · f711a6ae
    Sowmini Varadhan authored
    When running RDS over TCP, the active (client) side connects to the
    listening ("passive") side at the RDS_TCP_PORT.  After the connection
    is established, if the client side reboots (potentially without even
    sending a FIN) the server still has a TCP socket in the esablished
    state.  If the server-side now gets a new SYN comes from the client
    with a different client port, TCP will create a new socket-pair, but
    the RDS layer will incorrectly pull up the old rds_connection (which
    is still associated with the stale t_sock and RDS socket state).
    
    This patch corrects this behavior by having rds_tcp_accept_one()
    always create a new connection for an incoming TCP SYN.
    The rds and tcp state associated with the old socket-pair is cleaned
    up via the rds_tcp_state_change() callback which would typically be
    invoked in most cases when the client-TCP sends a FIN on TCP restart,
    triggering a transition to CLOSE_WAIT state. In the rarer event of client
    death without a FIN, TCP_KEEPALIVE probes on the socket will detect
    the stale socket, and the TCP transition to CLOSE state will trigger
    the RDS state cleanup.
    Signed-off-by: default avatarSowmini Varadhan <sowmini.varadhan@oracle.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    f711a6ae
tcp_connect.c 4.28 KB