Relax the restriction on routines from the config (#1531)

interface.go

@@ -222,6 +222,13 @@ func (f *Interface) activate() {
 		WithField("boringcrypto", boringEnabled()).
 		Info("Nebula interface is active")
 
+	if f.routines > 1 {
+		if !f.inside.SupportsMultiqueue() || !f.outside.SupportsMultipleReaders() {
+			f.routines = 1
+			f.l.Warn("routines is not supported on this platform, falling back to a single routine")
+		}
+	}
+
 	metrics.GetOrRegisterGauge("routines", nil).Update(int64(f.routines))
 
 	// Prepare n tun queues

overlay/device.go

@@ -13,5 +13,6 @@ type Device interface {
 	Networks() []netip.Prefix
 	Name() string
 	RoutesFor(netip.Addr) routing.Gateways
+	SupportsMultiqueue() bool
 	NewMultiQueueReader() (io.ReadWriteCloser, error)
 }

overlay/tun_android.go

@@ -95,6 +95,10 @@ func (t *tun) Name() string {
 	return "android"
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for android")
 }

overlay/tun_darwin.go

@@ -549,6 +549,10 @@ func (t *tun) Name() string {
 	return t.Device
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for darwin")
 }

overlay/tun_disabled.go

@@ -105,6 +105,10 @@ func (t *disabledTun) Write(b []byte) (int, error) {
 	return len(b), nil
 }
 
+func (t *disabledTun) SupportsMultiqueue() bool {
+	return true
+}
+
 func (t *disabledTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return t, nil
 }

overlay/tun_freebsd.go

@@ -450,6 +450,10 @@ func (t *tun) Name() string {
 	return t.Device
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for freebsd")
 }

overlay/tun_ios.go

@@ -151,6 +151,10 @@ func (t *tun) Name() string {
 	return "iOS"
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for ios")
 }

overlay/tun_linux.go

@@ -216,6 +216,10 @@ func (t *tun) reload(c *config.C, initial bool) error {
 	return nil
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return true
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	fd, err := unix.Open("/dev/net/tun", os.O_RDWR, 0)
 	if err != nil {

overlay/tun_netbsd.go

@@ -390,6 +390,10 @@ func (t *tun) Name() string {
 	return t.Device
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for netbsd")
 }

overlay/tun_openbsd.go

@@ -310,6 +310,10 @@ func (t *tun) Name() string {
 	return t.Device
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for openbsd")
 }

overlay/tun_tester.go

@@ -132,6 +132,10 @@ func (t *TestTun) Read(b []byte) (int, error) {
 	return len(p), nil
 }
 
+func (t *TestTun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *TestTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented")
 }

overlay/tun_windows.go

@@ -234,6 +234,10 @@ func (t *winTun) Write(b []byte) (int, error) {
 	return t.tun.Write(b, 0)
 }
 
+func (t *winTun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *winTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for windows")
 }

overlay/user.go

@@ -46,6 +46,10 @@ func (d *UserDevice) RoutesFor(ip netip.Addr) routing.Gateways {
 	return routing.Gateways{routing.NewGateway(ip, 1)}
 }
 
+func (d *UserDevice) SupportsMultiqueue() bool {
+	return true
+}
+
 func (d *UserDevice) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return d, nil
 }

test/tun.go

@@ -34,6 +34,10 @@ func (NoopTun) Write([]byte) (int, error) {
 	return 0, nil
 }
 
+func (NoopTun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (NoopTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, errors.New("unsupported")
 }

udp/conn.go

@@ -19,6 +19,7 @@ type Conn interface {
 	ListenOut(r EncReader)
 	WriteTo(b []byte, addr netip.AddrPort) error
 	ReloadConfig(c *config.C)
+	SupportsMultipleReaders() bool
 	Close() error
 }
 
@@ -33,6 +34,9 @@ func (NoopConn) LocalAddr() (netip.AddrPort, error) {
 func (NoopConn) ListenOut(_ EncReader) {
 	return
 }
+func (NoopConn) SupportsMultipleReaders() bool {
+	return false
+}
 func (NoopConn) WriteTo(_ []byte, _ netip.AddrPort) error {
 	return nil
 }

udp/udp_darwin.go

@@ -184,6 +184,10 @@ func (u *StdConn) ListenOut(r EncReader) {
 	}
 }
 
+func (u *StdConn) SupportsMultipleReaders() bool {
+	return false
+}
+
 func (u *StdConn) Rebind() error {
 	var err error
 	if u.isV4 {

udp/udp_generic.go

@@ -85,3 +85,7 @@ func (u *GenericConn) ListenOut(r EncReader) {
 		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n])
 	}
 }
+
+func (u *GenericConn) SupportsMultipleReaders() bool {
+	return false
+}

udp/udp_linux.go

@@ -72,6 +72,10 @@ func NewListener(l *logrus.Logger, ip netip.Addr, port int, multi bool, batch in
 	return &StdConn{sysFd: fd, isV4: ip.Is4(), l: l, batch: batch}, err
 }
 
+func (u *StdConn) SupportsMultipleReaders() bool {
+	return true
+}
+
 func (u *StdConn) Rebind() error {
 	return nil
 }

udp/udp_rio_windows.go

@@ -315,6 +315,10 @@ func (u *RIOConn) LocalAddr() (netip.AddrPort, error) {
 
 }
 
+func (u *RIOConn) SupportsMultipleReaders() bool {
+	return false
+}
+
 func (u *RIOConn) Rebind() error {
 	return nil
 }

udp/udp_tester.go

@@ -127,6 +127,10 @@ func (u *TesterConn) LocalAddr() (netip.AddrPort, error) {
 	return u.Addr, nil
 }
 
+func (u *TesterConn) SupportsMultipleReaders() bool {
+	return false
+}
+
 func (u *TesterConn) Rebind() error {
 	return nil
 }