config tweaks for batching

examples/config.yml

@@ -132,6 +132,13 @@ listen:
   # Sets the max number of packets to pull from the kernel for each syscall (under systems that support recvmmsg)
   # default is 64, does not support reload
   #batch: 64
+
+# Control batching between UDP and TUN pipelines
+#batch:
+#  inbound_size: 32        # packets to queue from UDP before handing to workers
+#  outbound_size: 32       # packets to queue from TUN before handing to workers
+#  flush_interval: 50us    # flush partially filled batches after this duration
+#  max_outstanding: 1028   # batches buffered per routine on each channel
   # Configure socket buffers for the udp side (outside), leave unset to use the system defaults. Values will be doubled by the kernel
   # Default is net.core.rmem_default and net.core.wmem_default (/proc/sys/net/core/rmem_default and /proc/sys/net/core/rmem_default)
   # Maximum is limited by memory in the system, SO_RCVBUFFORCE and SO_SNDBUFFORCE is used to avoid having to raise the system wide

interface.go

@@ -22,7 +22,14 @@ import (
 	"github.com/slackhq/nebula/udp"
 )
 
-const mtu = 9001
+const (
+	mtu = 9001
+
+	inboundBatchSizeDefault      = 32
+	outboundBatchSizeDefault     = 32
+	batchFlushIntervalDefault    = 50 * time.Microsecond
+	maxOutstandingBatchesDefault = 1028
+)
 
 type InterfaceConfig struct {
 	HostMap            *HostMap
@@ -48,9 +55,17 @@ type InterfaceConfig struct {
 	reQueryWait     time.Duration
 
 	ConntrackCacheTimeout time.Duration
+	BatchConfig           BatchConfig
 	l                     *logrus.Logger
 }
 
+type BatchConfig struct {
+	InboundBatchSize      int
+	OutboundBatchSize     int
+	FlushInterval         time.Duration
+	MaxOutstandingPerChan int
+}
+
 type Interface struct {
 	hostMap               *HostMap
 	outside               udp.Conn
@@ -97,10 +112,86 @@ type Interface struct {
 	l *logrus.Logger
 
 	inPool  sync.Pool
-	inbound chan *packet.Packet
+	inbound []chan *packetBatch
 
 	outPool  sync.Pool
-	outbound chan *[]byte
+	outbound []chan *outboundBatch
+
+	packetBatchPool   sync.Pool
+	outboundBatchPool sync.Pool
+
+	inboundBatchSize      int
+	outboundBatchSize     int
+	batchFlushInterval    time.Duration
+	maxOutstandingPerChan int
+}
+
+type packetBatch struct {
+	packets []*packet.Packet
+}
+
+func newPacketBatch(capacity int) *packetBatch {
+	return &packetBatch{
+		packets: make([]*packet.Packet, 0, capacity),
+	}
+}
+
+func (b *packetBatch) add(p *packet.Packet) {
+	b.packets = append(b.packets, p)
+}
+
+func (b *packetBatch) reset() {
+	for i := range b.packets {
+		b.packets[i] = nil
+	}
+	b.packets = b.packets[:0]
+}
+
+func (f *Interface) getPacketBatch() *packetBatch {
+	if v := f.packetBatchPool.Get(); v != nil {
+		b := v.(*packetBatch)
+		b.reset()
+		return b
+	}
+	return newPacketBatch(f.inboundBatchSize)
+}
+
+func (f *Interface) releasePacketBatch(b *packetBatch) {
+	b.reset()
+	f.packetBatchPool.Put(b)
+}
+
+type outboundBatch struct {
+	payloads []*[]byte
+}
+
+func newOutboundBatch(capacity int) *outboundBatch {
+	return &outboundBatch{payloads: make([]*[]byte, 0, capacity)}
+}
+
+func (b *outboundBatch) add(buf *[]byte) {
+	b.payloads = append(b.payloads, buf)
+}
+
+func (b *outboundBatch) reset() {
+	for i := range b.payloads {
+		b.payloads[i] = nil
+	}
+	b.payloads = b.payloads[:0]
+}
+
+func (f *Interface) getOutboundBatch() *outboundBatch {
+	if v := f.outboundBatchPool.Get(); v != nil {
+		b := v.(*outboundBatch)
+		b.reset()
+		return b
+	}
+	return newOutboundBatch(f.outboundBatchSize)
+}
+
+func (f *Interface) releaseOutboundBatch(b *outboundBatch) {
+	b.reset()
+	f.outboundBatchPool.Put(b)
 }
 
 type EncWriter interface {
@@ -170,6 +261,20 @@ func NewInterface(ctx context.Context, c *InterfaceConfig) (*Interface, error) {
 	}
 
 	cs := c.pki.getCertState()
+
+	bc := c.BatchConfig
+	if bc.InboundBatchSize <= 0 {
+		bc.InboundBatchSize = inboundBatchSizeDefault
+	}
+	if bc.OutboundBatchSize <= 0 {
+		bc.OutboundBatchSize = outboundBatchSizeDefault
+	}
+	if bc.FlushInterval <= 0 {
+		bc.FlushInterval = batchFlushIntervalDefault
+	}
+	if bc.MaxOutstandingPerChan <= 0 {
+		bc.MaxOutstandingPerChan = maxOutstandingBatchesDefault
+	}
 	ifce := &Interface{
 		pki:                   c.pki,
 		hostMap:               c.HostMap,
@@ -202,11 +307,20 @@ func NewInterface(ctx context.Context, c *InterfaceConfig) (*Interface, error) {
 			dropped: metrics.GetOrRegisterCounter("hostinfo.cached_packets.dropped", nil),
 		},
 
-		//TODO: configurable size
-		inbound:  make(chan *packet.Packet, 1028),
-		outbound: make(chan *[]byte, 1028),
+		inbound:  make([]chan *packetBatch, c.routines),
+		outbound: make([]chan *outboundBatch, c.routines),
 
 		l: c.l,
+
+		inboundBatchSize:      bc.InboundBatchSize,
+		outboundBatchSize:     bc.OutboundBatchSize,
+		batchFlushInterval:    bc.FlushInterval,
+		maxOutstandingPerChan: bc.MaxOutstandingPerChan,
+	}
+
+	for i := 0; i < c.routines; i++ {
+		ifce.inbound[i] = make(chan *packetBatch, ifce.maxOutstandingPerChan)
+		ifce.outbound[i] = make(chan *outboundBatch, ifce.maxOutstandingPerChan)
 	}
 
 	ifce.inPool = sync.Pool{New: func() any {
@@ -218,6 +332,14 @@ func NewInterface(ctx context.Context, c *InterfaceConfig) (*Interface, error) {
 		return &t
 	}}
 
+	ifce.packetBatchPool = sync.Pool{New: func() any {
+		return newPacketBatch(ifce.inboundBatchSize)
+	}}
+
+	ifce.outboundBatchPool = sync.Pool{New: func() any {
+		return newOutboundBatch(ifce.outboundBatchSize)
+	}}
+
 	ifce.tryPromoteEvery.Store(c.tryPromoteEvery)
 	ifce.reQueryEvery.Store(c.reQueryEvery)
 	ifce.reQueryWait.Store(int64(c.reQueryWait))
@@ -296,22 +418,41 @@ func (f *Interface) listenOut(i int) {
 		li = f.outside
 	}
 
+	batch := f.getPacketBatch()
+	lastFlush := time.Now()
+
+	flush := func(force bool) {
+		if len(batch.packets) == 0 {
+			if force {
+				f.releasePacketBatch(batch)
+			}
+			return
+		}
+
+		f.inbound[i] <- batch
+		batch = f.getPacketBatch()
+		lastFlush = time.Now()
+	}
+
 	err := li.ListenOut(func(fromUdpAddr netip.AddrPort, payload []byte) {
 		p := f.inPool.Get().(*packet.Packet)
-		//TODO: have the listener store this in the msgs array after a read instead of doing a copy
-
 		p.Payload = p.Payload[:mtu]
 		copy(p.Payload, payload)
 		p.Payload = p.Payload[:len(payload)]
 		p.Addr = fromUdpAddr
-		f.inbound <- p
-		//select {
-		//case f.inbound <- p:
-		//default:
-		//	f.l.Error("Dropped packet from inbound channel")
-		//}
+		batch.add(p)
+
+		if len(batch.packets) >= f.inboundBatchSize || time.Since(lastFlush) >= f.batchFlushInterval {
+			flush(false)
+		}
 	})
 
+	if len(batch.packets) > 0 {
+		f.inbound[i] <- batch
+	} else {
+		f.releasePacketBatch(batch)
+	}
+
 	if err != nil && !f.closed.Load() {
 		f.l.WithError(err).Error("Error while reading packet inbound packet, closing")
 		//TODO: Trigger Control to close
@@ -324,6 +465,22 @@ func (f *Interface) listenOut(i int) {
 func (f *Interface) listenIn(reader io.ReadWriteCloser, i int) {
 	runtime.LockOSThread()
 
+	batch := f.getOutboundBatch()
+	lastFlush := time.Now()
+
+	flush := func(force bool) {
+		if len(batch.payloads) == 0 {
+			if force {
+				f.releaseOutboundBatch(batch)
+			}
+			return
+		}
+
+		f.outbound[i] <- batch
+		batch = f.getOutboundBatch()
+		lastFlush = time.Now()
+	}
+
 	for {
 		p := f.outPool.Get().(*[]byte)
 		*p = (*p)[:mtu]
@@ -337,13 +494,17 @@ func (f *Interface) listenIn(reader io.ReadWriteCloser, i int) {
 		}
 
 		*p = (*p)[:n]
-		//TODO: nonblocking channel write
-		f.outbound <- p
-		//select {
-		//case f.outbound <- p:
-		//default:
-		//	f.l.Error("Dropped packet from outbound channel")
-		//}
+		batch.add(p)
+
+		if len(batch.payloads) >= f.outboundBatchSize || time.Since(lastFlush) >= f.batchFlushInterval {
+			flush(false)
+		}
+	}
+
+	if len(batch.payloads) > 0 {
+		f.outbound[i] <- batch
+	} else {
+		f.releaseOutboundBatch(batch)
 	}
 
 	f.l.Debugf("overlay reader %v is done", i)
@@ -360,10 +521,13 @@ func (f *Interface) workerIn(i int, ctx context.Context) {
 
 	for {
 		select {
-		case p := <-f.inbound:
-			f.readOutsidePackets(p.Addr, nil, result2[:0], p.Payload, h, fwPacket2, lhh, nb2, i, conntrackCache.Get(f.l))
-			p.Payload = p.Payload[:mtu]
-			f.inPool.Put(p)
+		case batch := <-f.inbound[i]:
+			for _, p := range batch.packets {
+				f.readOutsidePackets(p.Addr, nil, result2[:0], p.Payload, h, fwPacket2, lhh, nb2, i, conntrackCache.Get(f.l))
+				p.Payload = p.Payload[:mtu]
+				f.inPool.Put(p)
+			}
+			f.releasePacketBatch(batch)
 		case <-ctx.Done():
 			f.wg.Done()
 			return
@@ -379,10 +543,13 @@ func (f *Interface) workerOut(i int, ctx context.Context) {
 
 	for {
 		select {
-		case data := <-f.outbound:
-			f.consumeInsidePacket(*data, fwPacket1, nb1, result1, i, conntrackCache.Get(f.l))
-			*data = (*data)[:mtu]
-			f.outPool.Put(data)
+		case batch := <-f.outbound[i]:
+			for _, data := range batch.payloads {
+				f.consumeInsidePacket(*data, fwPacket1, nb1, result1, i, conntrackCache.Get(f.l))
+				*data = (*data)[:mtu]
+				f.outPool.Put(data)
+			}
+			f.releaseOutboundBatch(batch)
 		case <-ctx.Done():
 			f.wg.Done()
 			return

main.go

@@ -221,6 +221,13 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		}
 	}
 
+	batchCfg := BatchConfig{
+		InboundBatchSize:      c.GetInt("batch.inbound_size", inboundBatchSizeDefault),
+		OutboundBatchSize:     c.GetInt("batch.outbound_size", outboundBatchSizeDefault),
+		FlushInterval:         c.GetDuration("batch.flush_interval", batchFlushIntervalDefault),
+		MaxOutstandingPerChan: c.GetInt("batch.max_outstanding", maxOutstandingBatchesDefault),
+	}
+
 	ifConfig := &InterfaceConfig{
 		HostMap:               hostMap,
 		Inside:                tun,
@@ -242,6 +249,7 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		relayManager:          NewRelayManager(ctx, l, hostMap, c),
 		punchy:                punchy,
 		ConntrackCacheTimeout: conntrackCacheTimeout,
+		BatchConfig:           batchCfg,
 		l:                     l,
 	}
 

service/service.go

@@ -9,13 +9,10 @@ import (
 	"math"
 	"net"
 	"net/netip"
-	"os"
 	"strings"
 	"sync"
 
-	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula"
-	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/overlay"
 	"golang.org/x/sync/errgroup"
 	"gvisor.dev/gvisor/pkg/buffer"
@@ -46,15 +43,7 @@ type Service struct {
 	}
 }
 
-func New(config *config.C) (*Service, error) {
-	logger := logrus.New()
-	logger.Out = os.Stdout
-
-	control, err := nebula.Main(config, false, "custom-app", logger, overlay.NewUserDeviceFromConfig)
-	if err != nil {
-		return nil, err
-	}
-
+func New(control *nebula.Control) (*Service, error) {
 	wait, err := control.Start()
 	if err != nil {
 		return nil, err

udp/conn.go

@@ -30,8 +30,8 @@ func (NoopConn) Rebind() error {
 func (NoopConn) LocalAddr() (netip.AddrPort, error) {
 	return netip.AddrPort{}, nil
 }
-func (NoopConn) ListenOut(_ EncReader) {
-	return
+func (NoopConn) ListenOut(_ EncReader) error {
+	return nil
 }
 func (NoopConn) WriteTo(_ []byte, _ netip.AddrPort) error {
 	return nil