go/src/net/mptcpsock_linux.go

var mptcpOnce …

var mptcpAvailable …

var hasSOLMPTCP …

const _IPPROTO_MPTCP …

const _SOL_MPTCP …

const _MPTCP_INFO …

func supportsMultipathTCP() bool { … }

// Check that MPTCP is supported by attempting to create an MPTCP socket and by
// looking at the returned error if any.
func initMPTCPavailable() { … }

func (sd *sysDialer) dialMPTCP(ctx context.Context, laddr, raddr *TCPAddr) (*TCPConn, error) { … }

func (sl *sysListener) listenMPTCP(ctx context.Context, laddr *TCPAddr) (*TCPListener, error) { … }

// hasFallenBack reports whether the MPTCP connection has fallen back to "plain"
// TCP.
//
// A connection can fallback to TCP for different reasons, e.g. the other peer
// doesn't support it, a middle box "accidentally" drops the option, etc.
//
// If the MPTCP protocol has not been requested when creating the socket, this
// method will return true: MPTCP is not being used.
//
// Kernel >= 5.16 returns EOPNOTSUPP/ENOPROTOOPT in case of fallback.
// Older kernels will always return them even if MPTCP is used: not usable.
func hasFallenBack(fd *netFD) bool { … }

// isUsingMPTCPProto reports whether the socket protocol is MPTCP.
//
// Compared to hasFallenBack method, here only the socket protocol being used is
// checked: it can be MPTCP but it doesn't mean MPTCP is used on the wire, maybe
// a fallback to TCP has been done.
func isUsingMPTCPProto(fd *netFD) bool { … }

// isUsingMultipathTCP reports whether MPTCP is still being used.
//
// Please look at the description of hasFallenBack (kernel >=5.16) and
// isUsingMPTCPProto methods for more details about what is being checked here.
func isUsingMultipathTCP(fd *netFD) bool { … }