#unconditional
MPTCP_SUBFLOW_FLAG_MCAP_REM		(1 << 0)
MPTCP_SUBFLOW_FLAG_MCAP_LOC		(1 << 1)
MPTCP_SUBFLOW_FLAG_JOIN_REM		(1 << 2)
MPTCP_SUBFLOW_FLAG_JOIN_LOC		(1 << 3)
MPTCP_SUBFLOW_FLAG_BKUP_REM		(1 << 4)
MPTCP_SUBFLOW_FLAG_BKUP_LOC		(1 << 5)
MPTCP_SUBFLOW_FLAG_FULLY_ESTABLISHED	(1 << 6)
MPTCP_SUBFLOW_FLAG_CONNECTED		(1 << 7)
MPTCP_SUBFLOW_FLAG_MAPVALID		(1 << 8)