diff --git a/transport/internet/system_listener.go b/transport/internet/system_listener.go index 364d2d40..26e42dae 100644 --- a/transport/internet/system_listener.go +++ b/transport/internet/system_listener.go @@ -12,36 +12,57 @@ var ( effectiveListener = DefaultListener{} ) -type DefaultListener struct{} +type controller func(network, address string, fd uintptr) error -func (*DefaultListener) Listen(ctx context.Context, addr net.Addr, sockopt *SocketConfig) (net.Listener, error) { - var lc net.ListenConfig +type DefaultListener struct { + contollers []controller +} - if sockopt != nil { - lc.Control = func(network, address string, c syscall.RawConn) error { - return c.Control(func(fd uintptr) { +func getControlFunc(ctx context.Context, sockopt *SocketConfig, contollers []controller) func(network, address string, c syscall.RawConn) error { + return func(network, address string, c syscall.RawConn) error { + return c.Control(func(fd uintptr) { + if sockopt != nil { if err := applyInboundSocketOptions(network, fd, sockopt); err != nil { newError("failed to apply socket options to incoming connection").Base(err).WriteToLog(session.ExportIDToError(ctx)) } - }) - } + } + + for _, controller := range contollers { + if err := controller(network, address, fd); err != nil { + newError("failed to apply external controller").Base(err).WriteToLog(session.ExportIDToError(ctx)) + } + } + }) + } +} + +func (dl *DefaultListener) Listen(ctx context.Context, addr net.Addr, sockopt *SocketConfig) (net.Listener, error) { + var lc net.ListenConfig + + if sockopt != nil || len(dl.contollers) > 0 { + lc.Control = getControlFunc(ctx, sockopt, dl.contollers) } return lc.Listen(ctx, addr.Network(), addr.String()) } -func (*DefaultListener) ListenPacket(ctx context.Context, addr net.Addr, sockopt *SocketConfig) (net.PacketConn, error) { +func (dl *DefaultListener) ListenPacket(ctx context.Context, addr net.Addr, sockopt *SocketConfig) (net.PacketConn, error) { var lc net.ListenConfig - if sockopt != nil { - lc.Control = func(network, address string, c syscall.RawConn) error { - return c.Control(func(fd uintptr) { - if err := applyInboundSocketOptions(network, fd, sockopt); err != nil { - newError("failed to apply socket options to incoming connection").Base(err).WriteToLog(session.ExportIDToError(ctx)) - } - }) - } + if sockopt != nil || len(dl.contollers) > 0 { + lc.Control = getControlFunc(ctx, sockopt, dl.contollers) } return lc.ListenPacket(ctx, addr.Network(), addr.String()) } + +// RegisterListenerController adds a controller to the effective system listener. +// The controller can be used to operate on file descriptors before they are put into use. +func RegisterListenerController(controller func(network, address string, fd uintptr) error) error { + if controller == nil { + return newError("nil listener controller") + } + + effectiveListener.contollers = append(effectiveListener.contollers, controller) + return nil +} diff --git a/transport/internet/system_listener_test.go b/transport/internet/system_listener_test.go new file mode 100644 index 00000000..ae413615 --- /dev/null +++ b/transport/internet/system_listener_test.go @@ -0,0 +1,29 @@ +package internet_test + +import ( + "context" + "net" + "testing" + + "v2ray.com/core/common" + "v2ray.com/core/transport/internet" +) + +func TestRegisterListenerController(t *testing.T) { + var gotFd uintptr + + common.Must(internet.RegisterListenerController(func(network string, addr string, fd uintptr) error { + gotFd = fd + return nil + })) + + conn, err := internet.ListenSystemPacket(context.Background(), &net.UDPAddr{ + IP: net.IPv4zero, + }, nil) + common.Must(err) + common.Must(conn.Close()) + + if gotFd == 0 { + t.Error("expected none-zero fd, but actually 0") + } +}