tell stupid ai not to meddle with the paths on other platforms by adding a copy

CHANGELOG.md

@@ -7,12 +7,30 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Experimental Linux UDP offload support: enable `listen.enable_gso` and
+  `listen.enable_gro` to activate UDP_SEGMENT batching and GRO receive
+  splitting. Includes automatic capability probing, per-packet fallbacks, and
+  runtime metrics/logs for visibility.
+- Optional Linux TUN `virtio_net_hdr` support: set `tun.enable_vnet_hdr` to
+  have Nebula negotiate VNET headers and offload flags so future batches can
+  be delivered to the kernel with metadata instead of per-packet writes.
+- Linux UDP send sharding can now be tuned with `listen.send_shards`; defaults
+  to `GOMAXPROCS` but can be increased to stripe heavy peers across more
+  goroutines.
+
 ### Changed
 
 - `default_local_cidr_any` now defaults to false, meaning that any firewall rule
   intended to target an `unsafe_routes` entry must explicitly declare it via the
   `local_cidr` field. This is almost always the intended behavior. This flag is
   deprecated and will be removed in a future release.
+- UDP receive path now enqueues into per-worker lock-free rings, restoring the
+  `listen.decrypt_workers`/`listen.decrypt_queue_depth` tuning knobs while
+  eliminating the mutex contention from the old shared channel.
+- Increased replay protection window to 32k packets so high-throughput links
+  tolerate larger bursts of reordering without tripping the anti-replay logic.
 
 ## [1.9.4] - 2024-09-09
 

batch_pipeline.go

@@ -1,164 +0,0 @@
-package nebula
-
-import (
-	"net/netip"
-
-	"github.com/slackhq/nebula/overlay"
-	"github.com/slackhq/nebula/udp"
-)
-
-// batchPipelines tracks whether the inside device can operate on packet batches
-// and, if so, holds the shared packet pool sized for the virtio headroom and
-// payload limits advertised by the device. It also owns the fan-in/fan-out
-// queues between the TUN readers, encrypt/decrypt workers, and the UDP writers.
-type batchPipelines struct {
-	enabled    bool
-	inside     overlay.BatchCapableDevice
-	headroom   int
-	payloadCap int
-	pool       *overlay.PacketPool
-	batchSize  int
-	routines   int
-	rxQueues   []chan *overlay.Packet
-	txQueues   []chan queuedDatagram
-	tunQueues  []chan *overlay.Packet
-}
-
-type queuedDatagram struct {
-	packet *overlay.Packet
-	addr   netip.AddrPort
-}
-
-func (bp *batchPipelines) init(device overlay.Device, routines int, queueDepth int, maxSegments int) {
-	if device == nil || routines <= 0 {
-		return
-	}
-	bcap, ok := device.(overlay.BatchCapableDevice)
-	if !ok {
-		return
-	}
-	headroom := bcap.BatchHeadroom()
-	payload := bcap.BatchPayloadCap()
-	if maxSegments < 1 {
-		maxSegments = 1
-	}
-	requiredPayload := udp.MTU * maxSegments
-	if payload < requiredPayload {
-		payload = requiredPayload
-	}
-	batchSize := bcap.BatchSize()
-	if headroom <= 0 || payload <= 0 || batchSize <= 0 {
-		return
-	}
-	bp.enabled = true
-	bp.inside = bcap
-	bp.headroom = headroom
-	bp.payloadCap = payload
-	bp.batchSize = batchSize
-	bp.routines = routines
-	bp.pool = overlay.NewPacketPool(headroom, payload)
-	queueCap := batchSize * defaultBatchQueueDepthFactor
-	if queueDepth > 0 {
-		queueCap = queueDepth
-	}
-	if queueCap < batchSize {
-		queueCap = batchSize
-	}
-	bp.rxQueues = make([]chan *overlay.Packet, routines)
-	bp.txQueues = make([]chan queuedDatagram, routines)
-	bp.tunQueues = make([]chan *overlay.Packet, routines)
-	for i := 0; i < routines; i++ {
-		bp.rxQueues[i] = make(chan *overlay.Packet, queueCap)
-		bp.txQueues[i] = make(chan queuedDatagram, queueCap)
-		bp.tunQueues[i] = make(chan *overlay.Packet, queueCap)
-	}
-}
-
-func (bp *batchPipelines) Pool() *overlay.PacketPool {
-	if bp == nil || !bp.enabled {
-		return nil
-	}
-	return bp.pool
-}
-
-func (bp *batchPipelines) Enabled() bool {
-	return bp != nil && bp.enabled
-}
-
-func (bp *batchPipelines) batchSizeHint() int {
-	if bp == nil || bp.batchSize <= 0 {
-		return 1
-	}
-	return bp.batchSize
-}
-
-func (bp *batchPipelines) rxQueue(i int) chan *overlay.Packet {
-	if bp == nil || !bp.enabled || i < 0 || i >= len(bp.rxQueues) {
-		return nil
-	}
-	return bp.rxQueues[i]
-}
-
-func (bp *batchPipelines) txQueue(i int) chan queuedDatagram {
-	if bp == nil || !bp.enabled || i < 0 || i >= len(bp.txQueues) {
-		return nil
-	}
-	return bp.txQueues[i]
-}
-
-func (bp *batchPipelines) tunQueue(i int) chan *overlay.Packet {
-	if bp == nil || !bp.enabled || i < 0 || i >= len(bp.tunQueues) {
-		return nil
-	}
-	return bp.tunQueues[i]
-}
-
-func (bp *batchPipelines) txQueueLen(i int) int {
-	q := bp.txQueue(i)
-	if q == nil {
-		return 0
-	}
-	return len(q)
-}
-
-func (bp *batchPipelines) tunQueueLen(i int) int {
-	q := bp.tunQueue(i)
-	if q == nil {
-		return 0
-	}
-	return len(q)
-}
-
-func (bp *batchPipelines) enqueueRx(i int, pkt *overlay.Packet) bool {
-	q := bp.rxQueue(i)
-	if q == nil {
-		return false
-	}
-	q <- pkt
-	return true
-}
-
-func (bp *batchPipelines) enqueueTx(i int, pkt *overlay.Packet, addr netip.AddrPort) bool {
-	q := bp.txQueue(i)
-	if q == nil {
-		return false
-	}
-	q <- queuedDatagram{packet: pkt, addr: addr}
-	return true
-}
-
-func (bp *batchPipelines) enqueueTun(i int, pkt *overlay.Packet) bool {
-	q := bp.tunQueue(i)
-	if q == nil {
-		return false
-	}
-	q <- pkt
-	return true
-}
-
-func (bp *batchPipelines) newPacket() *overlay.Packet {
-	if bp == nil || !bp.enabled || bp.pool == nil {
-		return nil
-	}
-	return bp.pool.Get()
-}

cert/pem.go

@@ -1,10 +1,8 @@
 package cert
 
 import (
-	"encoding/hex"
 	"encoding/pem"
 	"fmt"
-	"time"
 
 	"golang.org/x/crypto/ed25519"
 )
@@ -140,101 +138,6 @@ func MarshalSigningPrivateKeyToPEM(curve Curve, b []byte) []byte {
 	}
 }
 
-// Backward compatibility functions for older API
-func MarshalX25519PublicKey(b []byte) []byte {
-	return MarshalPublicKeyToPEM(Curve_CURVE25519, b)
-}
-
-func MarshalX25519PrivateKey(b []byte) []byte {
-	return MarshalPrivateKeyToPEM(Curve_CURVE25519, b)
-}
-
-func MarshalPublicKey(curve Curve, b []byte) []byte {
-	return MarshalPublicKeyToPEM(curve, b)
-}
-
-func MarshalPrivateKey(curve Curve, b []byte) []byte {
-	return MarshalPrivateKeyToPEM(curve, b)
-}
-
-// NebulaCertificate is a compatibility wrapper for the old API
-type NebulaCertificate struct {
-	Details   NebulaCertificateDetails
-	Signature []byte
-	cert      Certificate
-}
-
-// NebulaCertificateDetails is a compatibility wrapper for certificate details
-type NebulaCertificateDetails struct {
-	Name      string
-	NotBefore time.Time
-	NotAfter  time.Time
-	PublicKey []byte
-	IsCA      bool
-	Issuer    []byte
-	Curve     Curve
-}
-
-// UnmarshalNebulaCertificateFromPEM provides backward compatibility with the old API
-func UnmarshalNebulaCertificateFromPEM(b []byte) (*NebulaCertificate, []byte, error) {
-	c, rest, err := UnmarshalCertificateFromPEM(b)
-	if err != nil {
-		return nil, rest, err
-	}
-
-	issuerBytes, err := func() ([]byte, error) {
-		issuer := c.Issuer()
-		if issuer == "" {
-			return nil, nil
-		}
-		decoded, err := hex.DecodeString(issuer)
-		if err != nil {
-			return nil, fmt.Errorf("failed to decode issuer fingerprint: %w", err)
-		}
-		return decoded, nil
-	}()
-	if err != nil {
-		return nil, rest, err
-	}
-
-	pubKey := c.PublicKey()
-	if pubKey != nil {
-		pubKey = append([]byte(nil), pubKey...)
-	}
-
-	sig := c.Signature()
-	if sig != nil {
-		sig = append([]byte(nil), sig...)
-	}
-
-	return &NebulaCertificate{
-		Details: NebulaCertificateDetails{
-			Name:      c.Name(),
-			NotBefore: c.NotBefore(),
-			NotAfter:  c.NotAfter(),
-			PublicKey: pubKey,
-			IsCA:      c.IsCA(),
-			Issuer:    issuerBytes,
-			Curve:     c.Curve(),
-		},
-		Signature: sig,
-		cert:      c,
-	}, rest, nil
-}
-
-// IssuerString returns the issuer in hex format for compatibility
-func (n *NebulaCertificate) IssuerString() string {
-	if n.Details.Issuer == nil {
-		return ""
-	}
-	return hex.EncodeToString(n.Details.Issuer)
-}
-
-// Certificate returns the underlying certificate (read-only)
-func (n *NebulaCertificate) Certificate() Certificate {
-	return n.cert
-}
-
 // UnmarshalPrivateKeyFromPEM will try to unmarshal the first pem block in a byte array, returning any non
 // consumed data or an error on failure
 func UnmarshalPrivateKeyFromPEM(b []byte) ([]byte, []byte, Curve, error) {

cert_test/cert.go

@@ -114,33 +114,6 @@ func NewTestCert(v cert.Version, curve cert.Curve, ca cert.Certificate, key []by
 	return c, pub, cert.MarshalPrivateKeyToPEM(curve, priv), pem
 }
 
-func NewTestCertDifferentVersion(c cert.Certificate, v cert.Version, ca cert.Certificate, key []byte) (cert.Certificate, []byte) {
-	nc := &cert.TBSCertificate{
-		Version:        v,
-		Curve:          c.Curve(),
-		Name:           c.Name(),
-		Networks:       c.Networks(),
-		UnsafeNetworks: c.UnsafeNetworks(),
-		Groups:         c.Groups(),
-		NotBefore:      time.Unix(c.NotBefore().Unix(), 0),
-		NotAfter:       time.Unix(c.NotAfter().Unix(), 0),
-		PublicKey:      c.PublicKey(),
-		IsCA:           false,
-	}
-
-	c, err := nc.Sign(ca, ca.Curve(), key)
-	if err != nil {
-		panic(err)
-	}
-
-	pem, err := c.MarshalPEM()
-	if err != nil {
-		panic(err)
-	}
-
-	return c, pem
-}
-
 func X25519Keypair() ([]byte, []byte) {
 	privkey := make([]byte, 32)
 	if _, err := io.ReadFull(rand.Reader, privkey); err != nil {

connection_manager.go

@@ -354,6 +354,7 @@ func (cm *connectionManager) makeTrafficDecision(localIndex uint32, now time.Tim
 
 		if mainHostInfo {
 			decision = tryRehandshake
+
 		} else {
 			if cm.shouldSwapPrimary(hostinfo) {
 				decision = swapPrimary
@@ -460,10 +461,6 @@ func (cm *connectionManager) shouldSwapPrimary(current *HostInfo) bool {
 	}
 
 	crt := cm.intf.pki.getCertState().getCertificate(current.ConnectionState.myCert.Version())
-	if crt == nil {
-		//my cert was reloaded away. We should definitely swap from this tunnel
-		return true
-	}
 	// If this tunnel is using the latest certificate then we should swap it to primary for a bit and see if things
 	// settle down.
 	return bytes.Equal(current.ConnectionState.myCert.Signature(), crt.Signature())
@@ -478,34 +475,31 @@ func (cm *connectionManager) swapPrimary(current, primary *HostInfo) {
 	cm.hostMap.Unlock()
 }
 
-// isInvalidCertificate decides if we should destroy a tunnel.
-// returns true if pki.disconnect_invalid is true and the certificate is no longer valid.
-// Blocklisted certificates will skip the pki.disconnect_invalid check and return true.
+// isInvalidCertificate will check if we should destroy a tunnel if pki.disconnect_invalid is true and
+// the certificate is no longer valid. Block listed certificates will skip the pki.disconnect_invalid
+// check and return true.
 func (cm *connectionManager) isInvalidCertificate(now time.Time, hostinfo *HostInfo) bool {
 	remoteCert := hostinfo.GetCert()
 	if remoteCert == nil {
-		return false //don't tear down tunnels for handshakes in progress
+		return false
 	}
 
 	caPool := cm.intf.pki.GetCAPool()
 	err := caPool.VerifyCachedCertificate(now, remoteCert)
 	if err == nil {
-		return false //cert is still valid! yay!
-	} else if err == cert.ErrBlockListed { //avoiding errors.Is for speed
-		// Block listed certificates should always be disconnected
-		hostinfo.logger(cm.l).WithError(err).
-			WithField("fingerprint", remoteCert.Fingerprint).
-			Info("Remote certificate is blocked, tearing down the tunnel")
-		return true
-	} else if cm.intf.disconnectInvalid.Load() {
-		hostinfo.logger(cm.l).WithError(err).
-			WithField("fingerprint", remoteCert.Fingerprint).
-			Info("Remote certificate is no longer valid, tearing down the tunnel")
-		return true
-	} else {
-		//if we reach here, the cert is no longer valid, but we're configured to keep tunnels from now-invalid certs open
 		return false
 	}
+
+	if !cm.intf.disconnectInvalid.Load() && err != cert.ErrBlockListed {
+		// Block listed certificates should always be disconnected
+		return false
+	}
+
+	hostinfo.logger(cm.l).WithError(err).
+		WithField("fingerprint", remoteCert.Fingerprint).
+		Info("Remote certificate is no longer valid, tearing down the tunnel")
+
+	return true
 }
 
 func (cm *connectionManager) sendPunch(hostinfo *HostInfo) {
@@ -536,45 +530,15 @@ func (cm *connectionManager) sendPunch(hostinfo *HostInfo) {
 func (cm *connectionManager) tryRehandshake(hostinfo *HostInfo) {
 	cs := cm.intf.pki.getCertState()
 	curCrt := hostinfo.ConnectionState.myCert
-	curCrtVersion := curCrt.Version()
-	myCrt := cs.getCertificate(curCrtVersion)
-	if myCrt == nil {
-		cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
-			WithField("version", curCrtVersion).
-			WithField("reason", "local certificate removed").
-			Info("Re-handshaking with remote")
-		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
+	myCrt := cs.getCertificate(curCrt.Version())
+	if curCrt.Version() >= cs.initiatingVersion && bytes.Equal(curCrt.Signature(), myCrt.Signature()) == true {
+		// The current tunnel is using the latest certificate and version, no need to rehandshake.
 		return
 	}
-	peerCrt := hostinfo.ConnectionState.peerCert
-	if peerCrt != nil && curCrtVersion < peerCrt.Certificate.Version() {
-		// if our certificate version is less than theirs, and we have a matching version available, rehandshake?
-		if cs.getCertificate(peerCrt.Certificate.Version()) != nil {
-			cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
-				WithField("version", curCrtVersion).
-				WithField("peerVersion", peerCrt.Certificate.Version()).
-				WithField("reason", "local certificate version lower than peer, attempting to correct").
-				Info("Re-handshaking with remote")
-			cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], func(hh *HandshakeHostInfo) {
-				hh.initiatingVersionOverride = peerCrt.Certificate.Version()
-			})
-			return
-		}
-	}
-	if !bytes.Equal(curCrt.Signature(), myCrt.Signature()) {
-		cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
-			WithField("reason", "local certificate is not current").
-			Info("Re-handshaking with remote")
 
-		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
-		return
-	}
-	if curCrtVersion < cs.initiatingVersion {
-		cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
-			WithField("reason", "current cert version < pki.initiatingVersion").
-			Info("Re-handshaking with remote")
+	cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+		WithField("reason", "local certificate is not current").
+		Info("Re-handshaking with remote")
 
-		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
-		return
-	}
+	cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
 }

connection_state.go

@@ -13,7 +13,10 @@ import (
 	"github.com/slackhq/nebula/noiseutil"
 )
 
-const ReplayWindow = 1024
+// ReplayWindow controls the size of the sliding window used to detect replays.
+// High-bandwidth links with GRO/GSO can reorder more than a thousand packets in
+// flight, so keep this comfortably above the largest expected burst.
+const ReplayWindow = 32768
 
 type ConnectionState struct {
 	eKey           *NebulaCipherState

e2e/helpers_test.go

@@ -129,109 +129,6 @@ func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name
 	return control, vpnNetworks, udpAddr, c
 }
 
-// newServer creates a nebula instance with fewer assumptions
-func newServer(caCrt []cert.Certificate, certs []cert.Certificate, key []byte, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
-	l := NewTestLogger()
-
-	vpnNetworks := certs[len(certs)-1].Networks()
-
-	var udpAddr netip.AddrPort
-	if vpnNetworks[0].Addr().Is4() {
-		budpIp := vpnNetworks[0].Addr().As4()
-		budpIp[1] -= 128
-		udpAddr = netip.AddrPortFrom(netip.AddrFrom4(budpIp), 4242)
-	} else {
-		budpIp := vpnNetworks[0].Addr().As16()
-		// beef for funsies
-		budpIp[2] = 190
-		budpIp[3] = 239
-		udpAddr = netip.AddrPortFrom(netip.AddrFrom16(budpIp), 4242)
-	}
-
-	caStr := ""
-	for _, ca := range caCrt {
-		x, err := ca.MarshalPEM()
-		if err != nil {
-			panic(err)
-		}
-		caStr += string(x)
-	}
-	certStr := ""
-	for _, c := range certs {
-		x, err := c.MarshalPEM()
-		if err != nil {
-			panic(err)
-		}
-		certStr += string(x)
-	}
-
-	mc := m{
-		"pki": m{
-			"ca":   caStr,
-			"cert": certStr,
-			"key":  string(key),
-		},
-		//"tun": m{"disabled": true},
-		"firewall": m{
-			"outbound": []m{{
-				"proto": "any",
-				"port":  "any",
-				"host":  "any",
-			}},
-			"inbound": []m{{
-				"proto": "any",
-				"port":  "any",
-				"host":  "any",
-			}},
-		},
-		//"handshakes": m{
-		//	"try_interval": "1s",
-		//},
-		"listen": m{
-			"host": udpAddr.Addr().String(),
-			"port": udpAddr.Port(),
-		},
-		"logging": m{
-			"timestamp_format": fmt.Sprintf("%v 15:04:05.000000", certs[0].Name()),
-			"level":            l.Level.String(),
-		},
-		"timers": m{
-			"pending_deletion_interval": 2,
-			"connection_alive_interval": 2,
-		},
-	}
-
-	if overrides != nil {
-		final := m{}
-		err := mergo.Merge(&final, overrides, mergo.WithAppendSlice)
-		if err != nil {
-			panic(err)
-		}
-		err = mergo.Merge(&final, mc, mergo.WithAppendSlice)
-		if err != nil {
-			panic(err)
-		}
-		mc = final
-	}
-
-	cb, err := yaml.Marshal(mc)
-	if err != nil {
-		panic(err)
-	}
-
-	c := config.NewC(l)
-	cStr := string(cb)
-	c.LoadString(cStr)
-
-	control, err := nebula.Main(c, false, "e2e-test", l, nil)
-
-	if err != nil {
-		panic(err)
-	}
-
-	return control, vpnNetworks, udpAddr, c
-}
-
 type doneCb func()
 
 func deadline(t *testing.T, seconds time.Duration) doneCb {

e2e/tunnels_test.go

@@ -4,16 +4,12 @@
 package e2e
 
 import (
-	"fmt"
-	"net/netip"
 	"testing"
 	"time"
 
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/cert_test"
 	"github.com/slackhq/nebula/e2e/router"
-	"github.com/stretchr/testify/assert"
-	"gopkg.in/yaml.v3"
 )
 
 func TestDropInactiveTunnels(t *testing.T) {
@@ -59,262 +55,3 @@ func TestDropInactiveTunnels(t *testing.T) {
 	myControl.Stop()
 	theirControl.Stop()
 }
-
-func TestCertUpgrade(t *testing.T) {
-	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
-	// under ideal conditions
-	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-	caB, err := ca.MarshalPEM()
-	if err != nil {
-		panic(err)
-	}
-	ca2, _, caKey2, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-
-	ca2B, err := ca2.MarshalPEM()
-	if err != nil {
-		panic(err)
-	}
-	caStr := fmt.Sprintf("%s\n%s", caB, ca2B)
-
-	myCert, _, myPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "me", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.1/24")}, nil, []string{})
-	_, myCert2Pem := cert_test.NewTestCertDifferentVersion(myCert, cert.Version2, ca2, caKey2)
-
-	theirCert, _, theirPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "them", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.2/24")}, nil, []string{})
-	theirCert2, _ := cert_test.NewTestCertDifferentVersion(theirCert, cert.Version2, ca2, caKey2)
-
-	myControl, myVpnIpNet, myUdpAddr, myC := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{myCert}, myPrivKey, m{})
-	theirControl, theirVpnIpNet, theirUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{theirCert, theirCert2}, theirPrivKey, m{})
-
-	// Share our underlay information
-	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
-	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
-
-	// Start the servers
-	myControl.Start()
-	theirControl.Start()
-
-	r := router.NewR(t, myControl, theirControl)
-	defer r.RenderFlow()
-
-	r.Log("Assert the tunnel between me and them works")
-	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
-	r.Log("yay")
-	//todo ???
-	time.Sleep(1 * time.Second)
-	r.FlushAll()
-
-	mc := m{
-		"pki": m{
-			"ca":   caStr,
-			"cert": string(myCert2Pem),
-			"key":  string(myPrivKey),
-		},
-		//"tun": m{"disabled": true},
-		"firewall": myC.Settings["firewall"],
-		//"handshakes": m{
-		//	"try_interval": "1s",
-		//},
-		"listen":  myC.Settings["listen"],
-		"logging": myC.Settings["logging"],
-		"timers":  myC.Settings["timers"],
-	}
-
-	cb, err := yaml.Marshal(mc)
-	if err != nil {
-		panic(err)
-	}
-
-	r.Logf("reload new v2-only config")
-	err = myC.ReloadConfigString(string(cb))
-	assert.NoError(t, err)
-	r.Log("yay, spin until their sees it")
-	waitStart := time.Now()
-	for {
-		assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
-		c := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
-		if c == nil {
-			r.Log("nil")
-		} else {
-			version := c.Cert.Version()
-			r.Logf("version %d", version)
-			if version == cert.Version2 {
-				break
-			}
-		}
-		since := time.Since(waitStart)
-		if since > time.Second*10 {
-			t.Fatal("Cert should be new by now")
-		}
-		time.Sleep(time.Second)
-	}
-
-	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
-
-	myControl.Stop()
-	theirControl.Stop()
-}
-
-func TestCertDowngrade(t *testing.T) {
-	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
-	// under ideal conditions
-	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-	caB, err := ca.MarshalPEM()
-	if err != nil {
-		panic(err)
-	}
-	ca2, _, caKey2, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-
-	ca2B, err := ca2.MarshalPEM()
-	if err != nil {
-		panic(err)
-	}
-	caStr := fmt.Sprintf("%s\n%s", caB, ca2B)
-
-	myCert, _, myPrivKey, myCertPem := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "me", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.1/24")}, nil, []string{})
-	myCert2, _ := cert_test.NewTestCertDifferentVersion(myCert, cert.Version2, ca2, caKey2)
-
-	theirCert, _, theirPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "them", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.2/24")}, nil, []string{})
-	theirCert2, _ := cert_test.NewTestCertDifferentVersion(theirCert, cert.Version2, ca2, caKey2)
-
-	myControl, myVpnIpNet, myUdpAddr, myC := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{myCert2}, myPrivKey, m{})
-	theirControl, theirVpnIpNet, theirUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{theirCert, theirCert2}, theirPrivKey, m{})
-
-	// Share our underlay information
-	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
-	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
-
-	// Start the servers
-	myControl.Start()
-	theirControl.Start()
-
-	r := router.NewR(t, myControl, theirControl)
-	defer r.RenderFlow()
-
-	r.Log("Assert the tunnel between me and them works")
-	//assertTunnel(t, theirVpnIpNet[0].Addr(), myVpnIpNet[0].Addr(), theirControl, myControl, r)
-	//r.Log("yay")
-	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
-	r.Log("yay")
-	//todo ???
-	time.Sleep(1 * time.Second)
-	r.FlushAll()
-
-	mc := m{
-		"pki": m{
-			"ca":   caStr,
-			"cert": string(myCertPem),
-			"key":  string(myPrivKey),
-		},
-		"firewall": myC.Settings["firewall"],
-		"listen":   myC.Settings["listen"],
-		"logging":  myC.Settings["logging"],
-		"timers":   myC.Settings["timers"],
-	}
-
-	cb, err := yaml.Marshal(mc)
-	if err != nil {
-		panic(err)
-	}
-
-	r.Logf("reload new v1-only config")
-	err = myC.ReloadConfigString(string(cb))
-	assert.NoError(t, err)
-	r.Log("yay, spin until their sees it")
-	waitStart := time.Now()
-	for {
-		assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
-		c := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
-		c2 := myControl.GetHostInfoByVpnAddr(theirVpnIpNet[0].Addr(), false)
-		if c == nil || c2 == nil {
-			r.Log("nil")
-		} else {
-			version := c.Cert.Version()
-			theirVersion := c2.Cert.Version()
-			r.Logf("version %d,%d", version, theirVersion)
-			if version == cert.Version1 {
-				break
-			}
-		}
-		since := time.Since(waitStart)
-		if since > time.Second*5 {
-			r.Log("it is unusual that the cert is not new yet, but not a failure yet")
-		}
-		if since > time.Second*10 {
-			r.Log("wtf")
-			t.Fatal("Cert should be new by now")
-		}
-		time.Sleep(time.Second)
-	}
-
-	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
-
-	myControl.Stop()
-	theirControl.Stop()
-}
-
-func TestCertMismatchCorrection(t *testing.T) {
-	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
-	// under ideal conditions
-	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-	ca2, _, caKey2, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-
-	myCert, _, myPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "me", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.1/24")}, nil, []string{})
-	myCert2, _ := cert_test.NewTestCertDifferentVersion(myCert, cert.Version2, ca2, caKey2)
-
-	theirCert, _, theirPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "them", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.2/24")}, nil, []string{})
-	theirCert2, _ := cert_test.NewTestCertDifferentVersion(theirCert, cert.Version2, ca2, caKey2)
-
-	myControl, myVpnIpNet, myUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{myCert2}, myPrivKey, m{})
-	theirControl, theirVpnIpNet, theirUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{theirCert, theirCert2}, theirPrivKey, m{})
-
-	// Share our underlay information
-	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
-	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
-
-	// Start the servers
-	myControl.Start()
-	theirControl.Start()
-
-	r := router.NewR(t, myControl, theirControl)
-	defer r.RenderFlow()
-
-	r.Log("Assert the tunnel between me and them works")
-	//assertTunnel(t, theirVpnIpNet[0].Addr(), myVpnIpNet[0].Addr(), theirControl, myControl, r)
-	//r.Log("yay")
-	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
-	r.Log("yay")
-	//todo ???
-	time.Sleep(1 * time.Second)
-	r.FlushAll()
-
-	waitStart := time.Now()
-	for {
-		assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
-		c := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
-		c2 := myControl.GetHostInfoByVpnAddr(theirVpnIpNet[0].Addr(), false)
-		if c == nil || c2 == nil {
-			r.Log("nil")
-		} else {
-			version := c.Cert.Version()
-			theirVersion := c2.Cert.Version()
-			r.Logf("version %d,%d", version, theirVersion)
-			if version == theirVersion {
-				break
-			}
-		}
-		since := time.Since(waitStart)
-		if since > time.Second*5 {
-			r.Log("wtf")
-		}
-		if since > time.Second*10 {
-			r.Log("wtf")
-			t.Fatal("Cert should be new by now")
-		}
-		time.Sleep(time.Second)
-	}
-
-	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
-
-	myControl.Stop()
-	theirControl.Stop()
-}

firewall.go

@@ -423,7 +423,7 @@ var ErrNoMatchingRule = errors.New("no matching rule in firewall table")
 
 // Drop returns an error if the packet should be dropped, explaining why. It
 // returns nil if the packet should not be dropped.
-func (f *Firewall) Drop(fp firewall.Packet, incoming bool, h *HostInfo, caPool *cert.CAPool, localCache *firewall.ConntrackCache) error {
+func (f *Firewall) Drop(fp firewall.Packet, incoming bool, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) error {
 	// Check if we spoke to this tuple, if we did then allow this packet
 	if f.inConns(fp, h, caPool, localCache) {
 		return nil
@@ -490,9 +490,11 @@ func (f *Firewall) EmitStats() {
 	metrics.GetOrRegisterGauge("firewall.rules.hash", nil).Update(int64(f.GetRuleHashFNV()))
 }
 
-func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool, localCache *firewall.ConntrackCache) bool {
-	if localCache != nil && localCache.Has(fp) {
-		return true
+func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) bool {
+	if localCache != nil {
+		if _, ok := localCache[fp]; ok {
+			return true
+		}
 	}
 	conntrack := f.Conntrack
 	conntrack.Lock()
@@ -557,7 +559,7 @@ func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool,
 	conntrack.Unlock()
 
 	if localCache != nil {
-		localCache.Add(fp)
+		localCache[fp] = struct{}{}
 	}
 
 	return true

firewall/cache.go

@@ -1,7 +1,6 @@
 package firewall
 
 import (
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -10,58 +9,13 @@ import (
 
 // ConntrackCache is used as a local routine cache to know if a given flow
 // has been seen in the conntrack table.
-type ConntrackCache struct {
-	mu      sync.Mutex
-	entries map[Packet]struct{}
-}
-
-func newConntrackCache() *ConntrackCache {
-	return &ConntrackCache{entries: make(map[Packet]struct{})}
-}
-
-func (c *ConntrackCache) Has(p Packet) bool {
-	if c == nil {
-		return false
-	}
-	c.mu.Lock()
-	_, ok := c.entries[p]
-	c.mu.Unlock()
-	return ok
-}
-
-func (c *ConntrackCache) Add(p Packet) {
-	if c == nil {
-		return
-	}
-	c.mu.Lock()
-	c.entries[p] = struct{}{}
-	c.mu.Unlock()
-}
-
-func (c *ConntrackCache) Len() int {
-	if c == nil {
-		return 0
-	}
-	c.mu.Lock()
-	l := len(c.entries)
-	c.mu.Unlock()
-	return l
-}
-
-func (c *ConntrackCache) Reset(capHint int) {
-	if c == nil {
-		return
-	}
-	c.mu.Lock()
-	c.entries = make(map[Packet]struct{}, capHint)
-	c.mu.Unlock()
-}
+type ConntrackCache map[Packet]struct{}
 
 type ConntrackCacheTicker struct {
 	cacheV    uint64
 	cacheTick atomic.Uint64
 
-	cache *ConntrackCache
+	cache ConntrackCache
 }
 
 func NewConntrackCacheTicker(d time.Duration) *ConntrackCacheTicker {
@@ -69,7 +23,9 @@ func NewConntrackCacheTicker(d time.Duration) *ConntrackCacheTicker {
 		return nil
 	}
 
-	c := &ConntrackCacheTicker{cache: newConntrackCache()}
+	c := &ConntrackCacheTicker{
+		cache: ConntrackCache{},
+	}
 
 	go c.tick(d)
 
@@ -85,17 +41,17 @@ func (c *ConntrackCacheTicker) tick(d time.Duration) {
 
 // Get checks if the cache ticker has moved to the next version before returning
 // the map. If it has moved, we reset the map.
-func (c *ConntrackCacheTicker) Get(l *logrus.Logger) *ConntrackCache {
+func (c *ConntrackCacheTicker) Get(l *logrus.Logger) ConntrackCache {
 	if c == nil {
 		return nil
 	}
 	if tick := c.cacheTick.Load(); tick != c.cacheV {
 		c.cacheV = tick
-		if ll := c.cache.Len(); ll > 0 {
+		if ll := len(c.cache); ll > 0 {
 			if l.Level == logrus.DebugLevel {
 				l.WithField("len", ll).Debug("resetting conntrack cache")
 			}
-			c.cache.Reset(ll)
+			c.cache = make(ConntrackCache, ll)
 		}
 	}
 

go.mod

@@ -6,7 +6,6 @@ require (
 	dario.cat/mergo v1.0.2
 	github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be
 	github.com/armon/go-radix v1.0.0
-	github.com/cilium/ebpf v0.12.3
 	github.com/cyberdelia/go-metrics-graphite v0.0.0-20161219230853-39f87cc3b432
 	github.com/flynn/noise v1.1.0
 	github.com/gaissmai/bart v0.25.0

go.sum

@@ -17,8 +17,6 @@ github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6r
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
-github.com/cilium/ebpf v0.12.3 h1:8ht6F9MquybnY97at+VDZb3eQQr8ev79RueWeVaEcG4=
-github.com/cilium/ebpf v0.12.3/go.mod h1:TctK1ivibvI3znr66ljgi4hqOT8EYQjz1KWBfb1UVgM=
 github.com/cyberdelia/go-metrics-graphite v0.0.0-20161219230853-39f87cc3b432 h1:M5QgkYacWj0Xs8MhpIK/5uwU02icXpEoSo9sM2aRCps=
 github.com/cyberdelia/go-metrics-graphite v0.0.0-20161219230853-39f87cc3b432/go.mod h1:xwIwAxMvYnVrGJPe2FKx5prTrnAjGOD8zvDOnxnrrkM=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -26,8 +24,6 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/flynn/noise v1.1.0 h1:KjPQoQCEFdZDiP03phOvGi11+SVVhBG2wOWAorLsstg=
 github.com/flynn/noise v1.1.0/go.mod h1:xbMo+0i6+IGbYdJhF31t2eR1BIU0CYc12+BNAKwUTag=
-github.com/frankban/quicktest v1.14.5 h1:dfYrrRyLtiqT9GyKXgdh+k4inNeTvmGbuSgZ3lx3GhA=
-github.com/frankban/quicktest v1.14.5/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
 github.com/gaissmai/bart v0.25.0 h1:eqiokVPqM3F94vJ0bTHXHtH91S8zkKL+bKh+BsGOsJM=
 github.com/gaissmai/bart v0.25.0/go.mod h1:GREWQfTLRWz/c5FTOsIw+KkscuFkIV5t8Rp7Nd1Td5c=
 github.com/go-kit/kit v0.8.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
@@ -82,9 +78,8 @@ github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfn
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
-github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=

handshake_ix.go

@@ -23,17 +23,13 @@ func ixHandshakeStage0(f *Interface, hh *HandshakeHostInfo) bool {
 		return false
 	}
 
+	// If we're connecting to a v6 address we must use a v2 cert
 	cs := f.pki.getCertState()
 	v := cs.initiatingVersion
-	if hh.initiatingVersionOverride != cert.VersionPre1 {
-		v = hh.initiatingVersionOverride
-	} else if v < cert.Version2 {
-		// If we're connecting to a v6 address we should encourage use of a V2 cert
-		for _, a := range hh.hostinfo.vpnAddrs {
-			if a.Is6() {
-				v = cert.Version2
-				break
-			}
+	for _, a := range hh.hostinfo.vpnAddrs {
+		if a.Is6() {
+			v = cert.Version2
+			break
 		}
 	}
 
@@ -52,7 +48,6 @@ func ixHandshakeStage0(f *Interface, hh *HandshakeHostInfo) bool {
 			WithField("handshake", m{"stage": 0, "style": "ix_psk0"}).
 			WithField("certVersion", v).
 			Error("Unable to handshake with host because no certificate handshake bytes is available")
-		return false
 	}
 
 	ci, err := NewConnectionState(f.l, cs, crt, true, noise.HandshakeIX)
@@ -108,7 +103,6 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 			WithField("handshake", m{"stage": 0, "style": "ix_psk0"}).
 			WithField("certVersion", cs.initiatingVersion).
 			Error("Unable to handshake with host because no certificate is available")
-		return
 	}
 
 	ci, err := NewConnectionState(f.l, cs, crt, false, noise.HandshakeIX)
@@ -149,8 +143,8 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	remoteCert, err := f.pki.GetCAPool().VerifyCertificate(time.Now(), rc)
 	if err != nil {
-		fp, fperr := rc.Fingerprint()
-		if fperr != nil {
+		fp, err := rc.Fingerprint()
+		if err != nil {
 			fp = "<error generating certificate fingerprint>"
 		}
 
@@ -169,19 +163,16 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	if remoteCert.Certificate.Version() != ci.myCert.Version() {
 		// We started off using the wrong certificate version, lets see if we can match the version that was sent to us
-		myCertOtherVersion := cs.getCertificate(remoteCert.Certificate.Version())
-		if myCertOtherVersion == nil {
-			if f.l.Level >= logrus.DebugLevel {
-				f.l.WithError(err).WithFields(m{
-					"udpAddr":   addr,
-					"handshake": m{"stage": 1, "style": "ix_psk0"},
-					"cert":      remoteCert,
-				}).Debug("Might be unable to handshake with host due to missing certificate version")
-			}
-		} else {
-			// Record the certificate we are actually using
-			ci.myCert = myCertOtherVersion
+		rc := cs.getCertificate(remoteCert.Certificate.Version())
+		if rc == nil {
+			f.l.WithError(err).WithField("udpAddr", addr).
+				WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).WithField("cert", remoteCert).
+				Info("Unable to handshake with host due to missing certificate version")
+			return
 		}
+
+		// Record the certificate we are actually using
+		ci.myCert = rc
 	}
 
 	if len(remoteCert.Certificate.Networks()) == 0 {

handshake_manager.go

@@ -68,12 +68,11 @@ type HandshakeManager struct {
 type HandshakeHostInfo struct {
 	sync.Mutex
 
-	startTime                 time.Time        // Time that we first started trying with this handshake
-	ready                     bool             // Is the handshake ready
-	initiatingVersionOverride cert.Version     // Should we use a non-default cert version for this handshake?
-	counter                   int64            // How many attempts have we made so far
-	lastRemotes               []netip.AddrPort // Remotes that we sent to during the previous attempt
-	packetStore               []*cachedPacket  // A set of packets to be transmitted once the handshake completes
+	startTime   time.Time        // Time that we first started trying with this handshake
+	ready       bool             // Is the handshake ready
+	counter     int64            // How many attempts have we made so far
+	lastRemotes []netip.AddrPort // Remotes that we sent to during the previous attempt
+	packetStore []*cachedPacket  // A set of packets to be transmitted once the handshake completes
 
 	hostinfo *HostInfo
 }

inside.go

@@ -2,18 +2,16 @@ package nebula
 
 import (
 	"net/netip"
-	"unsafe"
 
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/firewall"
 	"github.com/slackhq/nebula/header"
 	"github.com/slackhq/nebula/iputil"
 	"github.com/slackhq/nebula/noiseutil"
-	"github.com/slackhq/nebula/overlay"
 	"github.com/slackhq/nebula/routing"
 )
 
-func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet, nb, out []byte, q int, localCache *firewall.ConntrackCache) {
+func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet, nb, out []byte, q int, localCache firewall.ConntrackCache) {
 	err := newPacket(packet, false, fwPacket)
 	if err != nil {
 		if f.l.Level >= logrus.DebugLevel {
@@ -337,21 +335,9 @@ func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType
 	if ci.eKey == nil {
 		return
 	}
-	target := remote
-	if !target.IsValid() {
-		target = hostinfo.remote
-	}
-	useRelay := !target.IsValid()
+	useRelay := !remote.IsValid() && !hostinfo.remote.IsValid()
 	fullOut := out
 
-	var pkt *overlay.Packet
-	if !useRelay && f.batches.Enabled() {
-		pkt = f.batches.newPacket()
-		if pkt != nil {
-			out = pkt.Payload()[:0]
-		}
-	}
-
 	if useRelay {
 		if len(out) < header.Len {
 			// out always has a capacity of mtu, but not always a length greater than the header.Len.
@@ -385,85 +371,41 @@ func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType
 	}
 
 	var err error
-	if len(p) > 0 && slicesOverlap(out, p) {
-		tmp := make([]byte, len(p))
-		copy(tmp, p)
-		p = tmp
-	}
 	out, err = ci.eKey.EncryptDanger(out, out, p, c, nb)
 	if noiseutil.EncryptLockNeeded {
 		ci.writeLock.Unlock()
 	}
 	if err != nil {
-		if pkt != nil {
-			pkt.Release()
-		}
 		hostinfo.logger(f.l).WithError(err).
-			WithField("udpAddr", target).WithField("counter", c).
+			WithField("udpAddr", remote).WithField("counter", c).
 			WithField("attemptedCounter", c).
 			Error("Failed to encrypt outgoing packet")
 		return
 	}
 
-	if target.IsValid() {
-		if pkt != nil {
-			pkt.Len = len(out)
-			if f.l.Level >= logrus.DebugLevel {
-				f.l.WithFields(logrus.Fields{
-					"queue":        q,
-					"dest":         target,
-					"payload_len":  pkt.Len,
-					"use_batches":  true,
-					"remote_index": hostinfo.remoteIndexId,
-				}).Debug("enqueueing packet to UDP batch queue")
-			}
-			if f.tryQueuePacket(q, pkt, target) {
-				return
-			}
-			if f.l.Level >= logrus.DebugLevel {
-				f.l.WithFields(logrus.Fields{
-					"queue": q,
-					"dest":  target,
-				}).Debug("failed to enqueue packet; falling back to immediate send")
-			}
-			f.writeImmediatePacket(q, pkt, target, hostinfo)
-			return
-		}
-		if f.tryQueueDatagram(q, out, target) {
-			return
-		}
-		f.writeImmediate(q, out, target, hostinfo)
-		return
-	}
-
-	// fall back to relay path
-	if pkt != nil {
-		pkt.Release()
-	}
-
-	// Try to send via a relay
-	for _, relayIP := range hostinfo.relayState.CopyRelayIps() {
-		relayHostInfo, relay, err := f.hostMap.QueryVpnAddrsRelayFor(hostinfo.vpnAddrs, relayIP)
+	if remote.IsValid() {
+		err = f.writers[q].WriteTo(out, remote)
 		if err != nil {
-			hostinfo.relayState.DeleteRelay(relayIP)
-			hostinfo.logger(f.l).WithField("relay", relayIP).WithError(err).Info("sendNoMetrics failed to find HostInfo")
-			continue
+			hostinfo.logger(f.l).WithError(err).
+				WithField("udpAddr", remote).Error("Failed to write outgoing packet")
+		}
+	} else if hostinfo.remote.IsValid() {
+		err = f.writers[q].WriteTo(out, hostinfo.remote)
+		if err != nil {
+			hostinfo.logger(f.l).WithError(err).
+				WithField("udpAddr", remote).Error("Failed to write outgoing packet")
+		}
+	} else {
+		// Try to send via a relay
+		for _, relayIP := range hostinfo.relayState.CopyRelayIps() {
+			relayHostInfo, relay, err := f.hostMap.QueryVpnAddrsRelayFor(hostinfo.vpnAddrs, relayIP)
+			if err != nil {
+				hostinfo.relayState.DeleteRelay(relayIP)
+				hostinfo.logger(f.l).WithField("relay", relayIP).WithError(err).Info("sendNoMetrics failed to find HostInfo")
+				continue
+			}
+			f.SendVia(relayHostInfo, relay, out, nb, fullOut[:header.Len+len(out)], true)
+			break
 		}
-		f.SendVia(relayHostInfo, relay, out, nb, fullOut[:header.Len+len(out)], true)
-		break
 	}
 }
-
-// slicesOverlap reports whether the two byte slices share any portion of memory.
-// cipher.AEAD.Seal requires plaintext and dst to live in disjoint regions.
-func slicesOverlap(a, b []byte) bool {
-	if len(a) == 0 || len(b) == 0 {
-		return false
-	}
-
-	aStart := uintptr(unsafe.Pointer(&a[0]))
-	aEnd := aStart + uintptr(len(a))
-	bStart := uintptr(unsafe.Pointer(&b[0]))
-	bEnd := bStart + uintptr(len(b))
-	return aStart < bEnd && bStart < aEnd
-}

main.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
-	"runtime"
 	"time"
 
 	"github.com/sirupsen/logrus"
@@ -121,6 +120,8 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		l.WithField("duration", conntrackCacheTimeout).Info("Using routine-local conntrack cache")
 	}
 
+	udp.SetDisableUDPCsum(c.GetBool("listen.disable_udp_checksum", false))
+
 	var tun overlay.Device
 	if !configTest {
 		c.CatchHUP(ctx)
@@ -144,20 +145,6 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 	// set up our UDP listener
 	udpConns := make([]udp.Conn, routines)
 	port := c.GetInt("listen.port", 0)
-	enableGSO := c.GetBool("listen.enable_gso", true)
-	enableGRO := c.GetBool("listen.enable_gro", true)
-	gsoMaxSegments := c.GetInt("listen.gso_max_segments", defaultGSOMaxSegments)
-	if gsoMaxSegments <= 0 {
-		gsoMaxSegments = defaultGSOMaxSegments
-	}
-	if gsoMaxSegments > maxKernelGSOSegments {
-		gsoMaxSegments = maxKernelGSOSegments
-	}
-	gsoFlushTimeout := c.GetDuration("listen.gso_flush_timeout", defaultGSOFlushInterval)
-	if gsoFlushTimeout < 0 {
-		gsoFlushTimeout = 0
-	}
-	batchQueueDepth := c.GetInt("batch.queue_depth", 0)
 
 	if !configTest {
 		rawListenHost := c.GetString("listen.host", "0.0.0.0")
@@ -177,28 +164,13 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 			listenHost = ips[0].Unmap()
 		}
 
-		useWGDefault := runtime.GOOS == "linux"
-		useWG := c.GetBool("listen.use_wireguard_stack", useWGDefault)
-		var mkListener func(*logrus.Logger, netip.Addr, int, bool, int, int) (udp.Conn, error)
-		if useWG {
-			mkListener = udp.NewWireguardListener
-		} else {
-			mkListener = udp.NewListener
-		}
-
 		for i := 0; i < routines; i++ {
 			l.Infof("listening on %v", netip.AddrPortFrom(listenHost, uint16(port)))
-			udpServer, err := mkListener(l, listenHost, port, routines > 1, c.GetInt("listen.batch", 64), i)
+			udpServer, err := udp.NewListener(l, listenHost, port, routines > 1, c.GetInt("listen.batch", 64))
 			if err != nil {
 				return nil, util.NewContextualError("Failed to open udp listener", m{"queue": i}, err)
 			}
-			//todo set bpf on zeroth socket
 			udpServer.ReloadConfig(c)
-			if cfg, ok := udpServer.(interface {
-				ConfigureOffload(bool, bool, int)
-			}); ok {
-				cfg.ConfigureOffload(enableGSO, enableGRO, gsoMaxSegments)
-			}
 			udpConns[i] = udpServer
 
 			// If port is dynamic, discover it before the next pass through the for loop
@@ -251,6 +223,9 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		}
 	}
 
+	decryptWorkers := c.GetInt("listen.decrypt_workers", 0)
+	decryptQueueDepth := c.GetInt("listen.decrypt_queue_depth", 0)
+
 	ifConfig := &InterfaceConfig{
 		HostMap:               hostMap,
 		Inside:                tun,
@@ -266,18 +241,15 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		reQueryWait:           c.GetDuration("timers.requery_wait_duration", defaultReQueryWait),
 		DropLocalBroadcast:    c.GetBool("tun.drop_local_broadcast", false),
 		DropMulticast:         c.GetBool("tun.drop_multicast", false),
-		EnableGSO:             enableGSO,
-		EnableGRO:             enableGRO,
-		GSOMaxSegments:        gsoMaxSegments,
 		routines:              routines,
 		MessageMetrics:        messageMetrics,
 		version:               buildVersion,
 		relayManager:          NewRelayManager(ctx, l, hostMap, c),
 		punchy:                punchy,
 		ConntrackCacheTimeout: conntrackCacheTimeout,
-		BatchFlushInterval:    gsoFlushTimeout,
-		BatchQueueDepth:       batchQueueDepth,
 		l:                     l,
+		DecryptWorkers:        decryptWorkers,
+		DecryptQueueDepth:     decryptQueueDepth,
 	}
 
 	var ifce *Interface
@@ -288,7 +260,6 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		}
 
 		ifce.writers = udpConns
-		ifce.applyOffloadConfig(enableGSO, enableGRO, gsoMaxSegments)
 		lightHouse.ifce = ifce
 
 		ifce.RegisterConfigChangeCallbacks(c)

outside.go

@@ -12,7 +12,6 @@ import (
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/firewall"
 	"github.com/slackhq/nebula/header"
-	"github.com/slackhq/nebula/overlay"
 	"golang.org/x/net/ipv4"
 )
 
@@ -20,7 +19,7 @@ const (
 	minFwPacketLen = 4
 )
 
-func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []byte, packet []byte, h *header.H, fwPacket *firewall.Packet, lhf *LightHouseHandler, nb []byte, q int, localCache *firewall.ConntrackCache) {
+func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []byte, packet []byte, h *header.H, fwPacket *firewall.Packet, lhf *LightHouseHandler, nb []byte, q int, localCache firewall.ConntrackCache) {
 	err := h.Parse(packet)
 	if err != nil {
 		// Hole punch packets are 0 or 1 byte big, so lets ignore printing those errors
@@ -62,7 +61,7 @@ func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []
 
 		switch h.Subtype {
 		case header.MessageNone:
-			if !f.decryptToTun(hostinfo, h.MessageCounter, out, packet, fwPacket, nb, q, localCache, ip, h.RemoteIndex) {
+			if !f.decryptToTun(hostinfo, h.MessageCounter, out, packet, fwPacket, nb, q, localCache) {
 				return
 			}
 		case header.MessageRelay:
@@ -466,45 +465,29 @@ func (f *Interface) decrypt(hostinfo *HostInfo, mc uint64, out []byte, packet []
 	return out, nil
 }
 
-func (f *Interface) decryptToTun(hostinfo *HostInfo, messageCounter uint64, out []byte, packet []byte, fwPacket *firewall.Packet, nb []byte, q int, localCache *firewall.ConntrackCache, addr netip.AddrPort, recvIndex uint32) bool {
-	var (
-		err error
-		pkt *overlay.Packet
-	)
-
-	if f.batches.tunQueue(q) != nil {
-		pkt = f.batches.newPacket()
-		if pkt != nil {
-			out = pkt.Payload()[:0]
-		}
-	}
+func (f *Interface) decryptToTun(hostinfo *HostInfo, messageCounter uint64, out []byte, packet []byte, fwPacket *firewall.Packet, nb []byte, q int, localCache firewall.ConntrackCache) bool {
+	var err error
 
 	out, err = hostinfo.ConnectionState.dKey.DecryptDanger(out, packet[:header.Len], packet[header.Len:], messageCounter, nb)
 	if err != nil {
-		if pkt != nil {
-			pkt.Release()
-		}
-		hostinfo.logger(f.l).WithError(err).Error("Failed to decrypt packet")
-		if addr.IsValid() {
-			f.maybeSendRecvError(addr, recvIndex)
-		}
+		hostinfo.logger(f.l).
+			WithError(err).
+			WithField("tag", "decrypt-debug").
+			WithField("remoteIndexLocal", hostinfo.localIndexId).
+			WithField("messageCounter", messageCounter).
+			WithField("packet_len", len(packet)).
+			Error("Failed to decrypt packet")
 		return false
 	}
 
 	err = newPacket(out, true, fwPacket)
 	if err != nil {
-		if pkt != nil {
-			pkt.Release()
-		}
 		hostinfo.logger(f.l).WithError(err).WithField("packet", out).
 			Warnf("Error while validating inbound packet")
 		return false
 	}
 
 	if !hostinfo.ConnectionState.window.Update(f.l, messageCounter) {
-		if pkt != nil {
-			pkt.Release()
-		}
 		hostinfo.logger(f.l).WithField("fwPacket", fwPacket).
 			Debugln("dropping out of window packet")
 		return false
@@ -512,9 +495,6 @@ func (f *Interface) decryptToTun(hostinfo *HostInfo, messageCounter uint64, out
 
 	dropReason := f.firewall.Drop(*fwPacket, true, hostinfo, f.pki.GetCAPool(), localCache)
 	if dropReason != nil {
-		if pkt != nil {
-			pkt.Release()
-		}
 		// NOTE: We give `packet` as the `out` here since we already decrypted from it and we don't need it anymore
 		// This gives us a buffer to build the reject packet in
 		f.rejectOutside(out, hostinfo.ConnectionState, hostinfo, nb, packet, q)
@@ -527,17 +507,8 @@ func (f *Interface) decryptToTun(hostinfo *HostInfo, messageCounter uint64, out
 	}
 
 	f.connectionManager.In(hostinfo)
-	if pkt != nil {
-		pkt.Len = len(out)
-		if f.batches.enqueueTun(q, pkt) {
-			f.observeTunQueueLen(q)
-			return true
-		}
-		f.writePacketToTun(q, pkt)
-		return true
-	}
-
-	if _, err = f.readers[q].Write(out); err != nil {
+	_, err = f.readers[q].Write(out)
+	if err != nil {
 		f.l.WithError(err).Error("Failed to write to tun")
 	}
 	return true

overlay/device.go

@@ -3,7 +3,6 @@ package overlay
 import (
 	"io"
 	"net/netip"
-	"sync"
 
 	"github.com/slackhq/nebula/routing"
 )
@@ -16,84 +15,3 @@ type Device interface {
 	RoutesFor(netip.Addr) routing.Gateways
 	NewMultiQueueReader() (io.ReadWriteCloser, error)
 }
-
-// Packet represents a single packet buffer with optional headroom to carry
-// metadata (for example virtio-net headers).
-type Packet struct {
-	Buf     []byte
-	Offset  int
-	Len     int
-	release func()
-}
-
-func (p *Packet) Payload() []byte {
-	return p.Buf[p.Offset : p.Offset+p.Len]
-}
-
-func (p *Packet) Reset() {
-	p.Len = 0
-	p.Offset = 0
-	p.release = nil
-}
-
-func (p *Packet) Release() {
-	if p.release != nil {
-		p.release()
-		p.release = nil
-	}
-}
-
-func (p *Packet) Capacity() int {
-	return len(p.Buf) - p.Offset
-}
-
-// PacketPool manages reusable buffers with headroom.
-type PacketPool struct {
-	headroom int
-	blksz    int
-	pool     sync.Pool
-}
-
-func NewPacketPool(headroom, payload int) *PacketPool {
-	p := &PacketPool{headroom: headroom, blksz: headroom + payload}
-	p.pool.New = func() any {
-		buf := make([]byte, p.blksz)
-		return &Packet{Buf: buf, Offset: headroom}
-	}
-	return p
-}
-
-func (p *PacketPool) Get() *Packet {
-	pkt := p.pool.Get().(*Packet)
-	pkt.Offset = p.headroom
-	pkt.Len = 0
-	pkt.release = func() { p.put(pkt) }
-	return pkt
-}
-
-func (p *PacketPool) put(pkt *Packet) {
-	pkt.Reset()
-	p.pool.Put(pkt)
-}
-
-// BatchReader allows reading multiple packets into a shared pool with
-// preallocated headroom (e.g. virtio-net headers).
-type BatchReader interface {
-	ReadIntoBatch(pool *PacketPool) ([]*Packet, error)
-}
-
-// BatchWriter writes a slice of packets that carry their own metadata.
-type BatchWriter interface {
-	WriteBatch(packets []*Packet) (int, error)
-}
-
-// BatchCapableDevice describes a device that can efficiently read and write
-// batches of packets with virtio headroom.
-type BatchCapableDevice interface {
-	Device
-	BatchReader
-	BatchWriter
-	BatchHeadroom() int
-	BatchPayloadCap() int
-	BatchSize() int
-}

overlay/tun_linux.go

@@ -9,7 +9,6 @@ import (
 	"net"
 	"net/netip"
 	"os"
-	"runtime"
 	"strings"
 	"sync/atomic"
 	"time"
@@ -20,22 +19,23 @@ import (
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
-	wgtun "github.com/slackhq/nebula/wgstack/tun"
 	"github.com/vishvananda/netlink"
 	"golang.org/x/sys/unix"
 )
 
 type tun struct {
 	io.ReadWriteCloser
-	fd          int
-	Device      string
-	vpnNetworks []netip.Prefix
-	MaxMTU      int
-	DefaultMTU  int
-	TXQueueLen  int
-	deviceIndex int
-	ioctlFd     uintptr
-	wgDevice    wgtun.Device
+	fd            int
+	Device        string
+	vpnNetworks   []netip.Prefix
+	MaxMTU        int
+	DefaultMTU    int
+	TXQueueLen    int
+	deviceIndex   int
+	ioctlFd       uintptr
+	enableVnetHdr bool
+	vnetHdrLen    int
+	queues        []*tunQueue
 
 	Routes                    atomic.Pointer[[]Route]
 	routeTree                 atomic.Pointer[bart.Table[routing.Gateways]]
@@ -68,12 +68,90 @@ type ifreqQLEN struct {
 	pad   [8]byte
 }
 
+const (
+	virtioNetHdrLen     = 12
+	tunDefaultMaxPacket = 65536
+)
+
+type tunQueue struct {
+	file          *os.File
+	fd            int
+	enableVnetHdr bool
+	vnetHdrLen    int
+	maxPacket     int
+	writeScratch  []byte
+	readScratch   []byte
+	l             *logrus.Logger
+}
+
+func newTunQueue(file *os.File, enableVnetHdr bool, vnetHdrLen, maxPacket int, l *logrus.Logger) *tunQueue {
+	if maxPacket <= 0 {
+		maxPacket = tunDefaultMaxPacket
+	}
+	q := &tunQueue{
+		file:          file,
+		fd:            int(file.Fd()),
+		enableVnetHdr: enableVnetHdr,
+		vnetHdrLen:    vnetHdrLen,
+		maxPacket:     maxPacket,
+		l:             l,
+	}
+	if enableVnetHdr {
+		q.growReadScratch(maxPacket)
+	}
+	return q
+}
+
+func (q *tunQueue) growReadScratch(packetSize int) {
+	needed := q.vnetHdrLen + packetSize
+	if needed < q.vnetHdrLen+DefaultMTU {
+		needed = q.vnetHdrLen + DefaultMTU
+	}
+	if q.readScratch == nil || cap(q.readScratch) < needed {
+		q.readScratch = make([]byte, needed)
+	} else {
+		q.readScratch = q.readScratch[:needed]
+	}
+}
+
+func (q *tunQueue) setMaxPacket(packet int) {
+	if packet <= 0 {
+		packet = DefaultMTU
+	}
+	q.maxPacket = packet
+	if q.enableVnetHdr {
+		q.growReadScratch(packet)
+	}
+}
+
+func configureVnetHdr(fd int, hdrLen int, l *logrus.Logger) error {
+	features, err := unix.IoctlGetInt(fd, unix.TUNGETFEATURES)
+	if err == nil && features&unix.IFF_VNET_HDR == 0 {
+		return fmt.Errorf("kernel does not support IFF_VNET_HDR")
+	}
+	if err := unix.IoctlSetInt(fd, unix.TUNSETVNETHDRSZ, hdrLen); err != nil {
+		return err
+	}
+	offload := unix.TUN_F_CSUM | unix.TUN_F_UFO
+	if err := unix.IoctlSetInt(fd, unix.TUNSETOFFLOAD, offload); err != nil {
+		if l != nil {
+			l.WithError(err).Warn("Failed to enable TUN offload features")
+		}
+	}
+	return nil
+}
+
 func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
 	file := os.NewFile(uintptr(deviceFd), "/dev/net/tun")
+	enableVnetHdr := c.GetBool("tun.enable_vnet_hdr", false)
+	if enableVnetHdr {
+		if err := configureVnetHdr(deviceFd, virtioNetHdrLen, l); err != nil {
+			l.WithError(err).Warn("Failed to configure VNET header support on provided tun fd; disabling")
+			enableVnetHdr = false
+		}
+	}
 
-	useWGDefault := runtime.GOOS == "linux"
-	useWG := c.GetBool("tun.use_wireguard_stack", c.GetBool("listen.use_wireguard_stack", useWGDefault))
-	t, err := newTunGeneric(c, l, file, vpnNetworks, useWG)
+	t, err := newTunGeneric(c, l, file, vpnNetworks, enableVnetHdr)
 	if err != nil {
 		return nil, err
 	}
@@ -111,16 +189,25 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, multiqueu
 	if multiqueue {
 		req.Flags |= unix.IFF_MULTI_QUEUE
 	}
+	enableVnetHdr := c.GetBool("tun.enable_vnet_hdr", false)
+	if enableVnetHdr {
+		req.Flags |= unix.IFF_VNET_HDR
+	}
 	copy(req.Name[:], c.GetString("tun.dev", ""))
 	if err = ioctl(uintptr(fd), uintptr(unix.TUNSETIFF), uintptr(unsafe.Pointer(&req))); err != nil {
 		return nil, err
 	}
 	name := strings.Trim(string(req.Name[:]), "\x00")
 
+	if enableVnetHdr {
+		if err := configureVnetHdr(fd, virtioNetHdrLen, l); err != nil {
+			l.WithError(err).Warn("Failed to configure VNET header support on tun device; disabling")
+			enableVnetHdr = false
+		}
+	}
+
 	file := os.NewFile(uintptr(fd), "/dev/net/tun")
-	useWGDefault := runtime.GOOS == "linux"
-	useWG := c.GetBool("tun.use_wireguard_stack", c.GetBool("listen.use_wireguard_stack", useWGDefault))
-	t, err := newTunGeneric(c, l, file, vpnNetworks, useWG)
+	t, err := newTunGeneric(c, l, file, vpnNetworks, enableVnetHdr)
 	if err != nil {
 		return nil, err
 	}
@@ -130,50 +217,30 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, multiqueu
 	return t, nil
 }
 
-func newTunGeneric(c *config.C, l *logrus.Logger, file *os.File, vpnNetworks []netip.Prefix, useWireguard bool) (*tun, error) {
-	var (
-		rw    io.ReadWriteCloser = file
-		fd                       = int(file.Fd())
-		wgDev wgtun.Device
-	)
-
-	if useWireguard {
-		dev, err := wgtun.CreateTUNFromFile(file, c.GetInt("tun.mtu", DefaultMTU))
-		if err != nil {
-			return nil, fmt.Errorf("failed to initialize wireguard tun device: %w", err)
-		}
-		wgDev = dev
-		rw = newWireguardTunIO(dev, c.GetInt("tun.mtu", DefaultMTU))
-		fd = int(dev.File().Fd())
-	}
-
+func newTunGeneric(c *config.C, l *logrus.Logger, file *os.File, vpnNetworks []netip.Prefix, enableVnetHdr bool) (*tun, error) {
+	queue := newTunQueue(file, enableVnetHdr, virtioNetHdrLen, tunDefaultMaxPacket, l)
 	t := &tun{
-		ReadWriteCloser:           rw,
-		fd:                        fd,
+		ReadWriteCloser:           queue,
+		fd:                        int(file.Fd()),
 		vpnNetworks:               vpnNetworks,
 		TXQueueLen:                c.GetInt("tun.tx_queue", 500),
 		useSystemRoutes:           c.GetBool("tun.use_system_route_table", false),
 		useSystemRoutesBufferSize: c.GetInt("tun.use_system_route_table_buffer_size", 0),
 		l:                         l,
-	}
-	if wgDev != nil {
-		t.wgDevice = wgDev
-	}
-	if wgDev != nil {
-		// replace ioctl fd with device file descriptor to keep route management working
-		file = wgDev.File()
-		t.fd = int(file.Fd())
-		t.ioctlFd = file.Fd()
-	}
-
-	if t.ioctlFd == 0 {
-		t.ioctlFd = file.Fd()
+		enableVnetHdr:             enableVnetHdr,
+		vnetHdrLen:                virtioNetHdrLen,
+		queues:                    []*tunQueue{queue},
 	}
 
 	err := t.reload(c, true)
 	if err != nil {
 		return nil, err
 	}
+	if enableVnetHdr {
+		for _, q := range t.queues {
+			q.setMaxPacket(t.MaxMTU)
+		}
+	}
 
 	c.RegisterReloadCallback(func(c *config.C) {
 		err := t.reload(c, false)
@@ -216,6 +283,11 @@ func (t *tun) reload(c *config.C, initial bool) error {
 
 	t.MaxMTU = newMaxMTU
 	t.DefaultMTU = newDefaultMTU
+	if t.enableVnetHdr {
+		for _, q := range t.queues {
+			q.setMaxPacket(t.MaxMTU)
+		}
+	}
 
 	// Teach nebula how to handle the routes before establishing them in the system table
 	oldRoutes := t.Routes.Swap(&routes)
@@ -260,14 +332,87 @@ func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 
 	var req ifReq
 	req.Flags = uint16(unix.IFF_TUN | unix.IFF_NO_PI | unix.IFF_MULTI_QUEUE)
+	if t.enableVnetHdr {
+		req.Flags |= unix.IFF_VNET_HDR
+	}
 	copy(req.Name[:], t.Device)
 	if err = ioctl(uintptr(fd), uintptr(unix.TUNSETIFF), uintptr(unsafe.Pointer(&req))); err != nil {
 		return nil, err
 	}
 
 	file := os.NewFile(uintptr(fd), "/dev/net/tun")
+	queue := newTunQueue(file, t.enableVnetHdr, t.vnetHdrLen, t.MaxMTU, t.l)
+	if t.enableVnetHdr {
+		if err := configureVnetHdr(fd, t.vnetHdrLen, t.l); err != nil {
+			queue.enableVnetHdr = false
+		}
+	}
+	t.queues = append(t.queues, queue)
 
-	return file, nil
+	return queue, nil
+}
+
+func (q *tunQueue) Read(p []byte) (int, error) {
+	if !q.enableVnetHdr {
+		return q.file.Read(p)
+	}
+
+	if len(p)+q.vnetHdrLen > cap(q.readScratch) {
+		q.growReadScratch(len(p))
+	}
+
+	buf := q.readScratch[:cap(q.readScratch)]
+	n, err := q.file.Read(buf)
+	if n <= 0 {
+		return n, err
+	}
+	if n < q.vnetHdrLen {
+		if err == nil {
+			err = io.ErrUnexpectedEOF
+		}
+		return 0, err
+	}
+
+	payload := buf[q.vnetHdrLen:n]
+	if len(payload) > len(p) {
+		copy(p, payload[:len(p)])
+		if err == nil {
+			err = io.ErrShortBuffer
+		}
+		return len(p), err
+	}
+	copy(p, payload)
+	return len(payload), err
+}
+
+func (q *tunQueue) Write(b []byte) (int, error) {
+	if !q.enableVnetHdr {
+		return unix.Write(q.fd, b)
+	}
+
+	total := q.vnetHdrLen + len(b)
+	if cap(q.writeScratch) < total {
+		q.writeScratch = make([]byte, total)
+	} else {
+		q.writeScratch = q.writeScratch[:total]
+	}
+
+	for i := 0; i < q.vnetHdrLen; i++ {
+		q.writeScratch[i] = 0
+	}
+	copy(q.writeScratch[q.vnetHdrLen:], b)
+
+	n, err := unix.Write(q.fd, q.writeScratch)
+	if n >= q.vnetHdrLen {
+		n -= q.vnetHdrLen
+	} else {
+		n = 0
+	}
+	return n, err
+}
+
+func (q *tunQueue) Close() error {
+	return q.file.Close()
 }
 
 func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
@@ -714,14 +859,6 @@ func (t *tun) Close() error {
 		_ = t.ReadWriteCloser.Close()
 	}
 
-	if t.wgDevice != nil {
-		_ = t.wgDevice.Close()
-		if t.ioctlFd > 0 {
-			// underlying fd already closed by the device
-			t.ioctlFd = 0
-		}
-	}
-
 	if t.ioctlFd > 0 {
 		_ = os.NewFile(t.ioctlFd, "ioctlFd").Close()
 	}

overlay/tun_linux_batch.go

@@ -1,56 +0,0 @@
-//go:build linux && !android && !e2e_testing
-
-package overlay
-
-import "fmt"
-
-func (t *tun) batchIO() (*wireguardTunIO, bool) {
-	io, ok := t.ReadWriteCloser.(*wireguardTunIO)
-	return io, ok
-}
-
-func (t *tun) ReadIntoBatch(pool *PacketPool) ([]*Packet, error) {
-	io, ok := t.batchIO()
-	if !ok {
-		return nil, fmt.Errorf("wireguard batch I/O not enabled")
-	}
-	return io.ReadIntoBatch(pool)
-}
-
-func (t *tun) WriteBatch(packets []*Packet) (int, error) {
-	io, ok := t.batchIO()
-	if ok {
-		return io.WriteBatch(packets)
-	}
-	for _, pkt := range packets {
-		if pkt == nil {
-			continue
-		}
-		if _, err := t.Write(pkt.Payload()[:pkt.Len]); err != nil {
-			return 0, err
-		}
-		pkt.Release()
-	}
-	return len(packets), nil
-}
-
-func (t *tun) BatchHeadroom() int {
-	if io, ok := t.batchIO(); ok {
-		return io.BatchHeadroom()
-	}
-	return 0
-}
-
-func (t *tun) BatchPayloadCap() int {
-	if io, ok := t.batchIO(); ok {
-		return io.BatchPayloadCap()
-	}
-	return 0
-}
-
-func (t *tun) BatchSize() int {
-	if io, ok := t.batchIO(); ok {
-		return io.BatchSize()
-	}
-	return 1
-}

overlay/wireguard_tun_linux.go

@@ -1,220 +0,0 @@
-//go:build linux && !android && !e2e_testing
-
-package overlay
-
-import (
-	"fmt"
-	"sync"
-
-	wgtun "github.com/slackhq/nebula/wgstack/tun"
-)
-
-type wireguardTunIO struct {
-	dev       wgtun.Device
-	mtu       int
-	batchSize int
-
-	readMu      sync.Mutex
-	readBuffers [][]byte
-	readLens    []int
-	legacyBuf   []byte
-
-	writeMu      sync.Mutex
-	writeBuf     []byte
-	writeWrap    [][]byte
-	writeBuffers [][]byte
-}
-
-func newWireguardTunIO(dev wgtun.Device, mtu int) *wireguardTunIO {
-	batch := dev.BatchSize()
-	if batch <= 0 {
-		batch = 1
-	}
-	if mtu <= 0 {
-		mtu = DefaultMTU
-	}
-	return &wireguardTunIO{
-		dev:       dev,
-		mtu:       mtu,
-		batchSize: batch,
-		readLens:  make([]int, batch),
-		legacyBuf: make([]byte, wgtun.VirtioNetHdrLen+mtu),
-		writeBuf:  make([]byte, wgtun.VirtioNetHdrLen+mtu),
-		writeWrap: make([][]byte, 1),
-	}
-}
-
-func (w *wireguardTunIO) Read(p []byte) (int, error) {
-	w.readMu.Lock()
-	defer w.readMu.Unlock()
-
-	bufs := w.readBuffers
-	if len(bufs) == 0 {
-		bufs = [][]byte{w.legacyBuf}
-		w.readBuffers = bufs
-	}
-	n, err := w.dev.Read(bufs[:1], w.readLens[:1], wgtun.VirtioNetHdrLen)
-	if err != nil {
-		return 0, err
-	}
-	if n == 0 {
-		return 0, nil
-	}
-	length := w.readLens[0]
-	copy(p, w.legacyBuf[wgtun.VirtioNetHdrLen:wgtun.VirtioNetHdrLen+length])
-	return length, nil
-}
-
-func (w *wireguardTunIO) Write(p []byte) (int, error) {
-	if len(p) > w.mtu {
-		return 0, fmt.Errorf("wireguard tun: payload exceeds MTU (%d > %d)", len(p), w.mtu)
-	}
-	w.writeMu.Lock()
-	defer w.writeMu.Unlock()
-	buf := w.writeBuf[:wgtun.VirtioNetHdrLen+len(p)]
-	for i := 0; i < wgtun.VirtioNetHdrLen; i++ {
-		buf[i] = 0
-	}
-	copy(buf[wgtun.VirtioNetHdrLen:], p)
-	w.writeWrap[0] = buf
-	n, err := w.dev.Write(w.writeWrap, wgtun.VirtioNetHdrLen)
-	if err != nil {
-		return n, err
-	}
-	return len(p), nil
-}
-
-func (w *wireguardTunIO) ReadIntoBatch(pool *PacketPool) ([]*Packet, error) {
-	if pool == nil {
-		return nil, fmt.Errorf("wireguard tun: packet pool is nil")
-	}
-
-	w.readMu.Lock()
-	defer w.readMu.Unlock()
-
-	if len(w.readBuffers) < w.batchSize {
-		w.readBuffers = make([][]byte, w.batchSize)
-	}
-	if len(w.readLens) < w.batchSize {
-		w.readLens = make([]int, w.batchSize)
-	}
-
-	packets := make([]*Packet, w.batchSize)
-	requiredHeadroom := w.BatchHeadroom()
-	requiredPayload := w.BatchPayloadCap()
-	headroom := 0
-	for i := 0; i < w.batchSize; i++ {
-		pkt := pool.Get()
-		if pkt == nil {
-			releasePackets(packets[:i])
-			return nil, fmt.Errorf("wireguard tun: packet pool returned nil packet")
-		}
-		if pkt.Capacity() < requiredPayload {
-			pkt.Release()
-			releasePackets(packets[:i])
-			return nil, fmt.Errorf("wireguard tun: packet capacity %d below required %d", pkt.Capacity(), requiredPayload)
-		}
-		if i == 0 {
-			headroom = pkt.Offset
-			if headroom < requiredHeadroom {
-				pkt.Release()
-				releasePackets(packets[:i])
-				return nil, fmt.Errorf("wireguard tun: packet headroom %d below virtio requirement %d", headroom, requiredHeadroom)
-			}
-		} else if pkt.Offset != headroom {
-			pkt.Release()
-			releasePackets(packets[:i])
-			return nil, fmt.Errorf("wireguard tun: inconsistent packet headroom (%d != %d)", pkt.Offset, headroom)
-		}
-		packets[i] = pkt
-		w.readBuffers[i] = pkt.Buf
-	}
-
-	n, err := w.dev.Read(w.readBuffers[:w.batchSize], w.readLens[:w.batchSize], headroom)
-	if err != nil {
-		releasePackets(packets)
-		return nil, err
-	}
-	if n == 0 {
-		releasePackets(packets)
-		return nil, nil
-	}
-	for i := 0; i < n; i++ {
-		packets[i].Len = w.readLens[i]
-	}
-	for i := n; i < w.batchSize; i++ {
-		packets[i].Release()
-		packets[i] = nil
-	}
-	return packets[:n], nil
-}
-
-func (w *wireguardTunIO) WriteBatch(packets []*Packet) (int, error) {
-	if len(packets) == 0 {
-		return 0, nil
-	}
-	requiredHeadroom := w.BatchHeadroom()
-	offset := packets[0].Offset
-	if offset < requiredHeadroom {
-		releasePackets(packets)
-		return 0, fmt.Errorf("wireguard tun: packet offset %d smaller than required headroom %d", offset, requiredHeadroom)
-	}
-	for _, pkt := range packets {
-		if pkt == nil {
-			continue
-		}
-		if pkt.Offset != offset {
-			releasePackets(packets)
-			return 0, fmt.Errorf("wireguard tun: mixed packet offsets not supported")
-		}
-		limit := pkt.Offset + pkt.Len
-		if limit > len(pkt.Buf) {
-			releasePackets(packets)
-			return 0, fmt.Errorf("wireguard tun: packet length %d exceeds buffer capacity %d", pkt.Len, len(pkt.Buf)-pkt.Offset)
-		}
-	}
-	w.writeMu.Lock()
-	defer w.writeMu.Unlock()
-
-	if len(w.writeBuffers) < len(packets) {
-		w.writeBuffers = make([][]byte, len(packets))
-	}
-	for i, pkt := range packets {
-		if pkt == nil {
-			w.writeBuffers[i] = nil
-			continue
-		}
-		limit := pkt.Offset + pkt.Len
-		w.writeBuffers[i] = pkt.Buf[:limit]
-	}
-	n, err := w.dev.Write(w.writeBuffers[:len(packets)], offset)
-	if err != nil {
-		return n, err
-	}
-	releasePackets(packets)
-	return n, nil
-}
-
-func (w *wireguardTunIO) BatchHeadroom() int {
-	return wgtun.VirtioNetHdrLen
-}
-
-func (w *wireguardTunIO) BatchPayloadCap() int {
-	return w.mtu
-}
-
-func (w *wireguardTunIO) BatchSize() int {
-	return w.batchSize
-}
-
-func (w *wireguardTunIO) Close() error {
-	return nil
-}
-
-func releasePackets(pkts []*Packet) {
-	for _, pkt := range pkts {
-		if pkt != nil {
-			pkt.Release()
-		}
-	}
-}

pki.go

@@ -100,62 +100,55 @@ func (p *PKI) reloadCerts(c *config.C, initial bool) *util.ContextualError {
 		currentState := p.cs.Load()
 		if newState.v1Cert != nil {
 			if currentState.v1Cert == nil {
-				//adding certs is fine, actually. Networks-in-common confirmed in newCertState().
-			} else {
-				// did IP in cert change? if so, don't set
-				if !slices.Equal(currentState.v1Cert.Networks(), newState.v1Cert.Networks()) {
-					return util.NewContextualError(
-						"Networks in new cert was different from old",
-						m{"new_networks": newState.v1Cert.Networks(), "old_networks": currentState.v1Cert.Networks(), "cert_version": cert.Version1},
-						nil,
-					)
-				}
-
-				if currentState.v1Cert.Curve() != newState.v1Cert.Curve() {
-					return util.NewContextualError(
-						"Curve in new v1 cert was different from old",
-						m{"new_curve": newState.v1Cert.Curve(), "old_curve": currentState.v1Cert.Curve(), "cert_version": cert.Version1},
-						nil,
-					)
-				}
+				return util.NewContextualError("v1 certificate was added, restart required", nil, err)
 			}
+
+			// did IP in cert change? if so, don't set
+			if !slices.Equal(currentState.v1Cert.Networks(), newState.v1Cert.Networks()) {
+				return util.NewContextualError(
+					"Networks in new cert was different from old",
+					m{"new_networks": newState.v1Cert.Networks(), "old_networks": currentState.v1Cert.Networks()},
+					nil,
+				)
+			}
+
+			if currentState.v1Cert.Curve() != newState.v1Cert.Curve() {
+				return util.NewContextualError(
+					"Curve in new cert was different from old",
+					m{"new_curve": newState.v1Cert.Curve(), "old_curve": currentState.v1Cert.Curve()},
+					nil,
+				)
+			}
+
+		} else if currentState.v1Cert != nil {
+			//TODO: CERT-V2 we should be able to tear this down
+			return util.NewContextualError("v1 certificate was removed, restart required", nil, err)
 		}
 
 		if newState.v2Cert != nil {
 			if currentState.v2Cert == nil {
-				//adding certs is fine, actually
-			} else {
-				// did IP in cert change? if so, don't set
-				if !slices.Equal(currentState.v2Cert.Networks(), newState.v2Cert.Networks()) {
-					return util.NewContextualError(
-						"Networks in new cert was different from old",
-						m{"new_networks": newState.v2Cert.Networks(), "old_networks": currentState.v2Cert.Networks(), "cert_version": cert.Version2},
-						nil,
-					)
-				}
-
-				if currentState.v2Cert.Curve() != newState.v2Cert.Curve() {
-					return util.NewContextualError(
-						"Curve in new cert was different from old",
-						m{"new_curve": newState.v2Cert.Curve(), "old_curve": currentState.v2Cert.Curve(), "cert_version": cert.Version2},
-						nil,
-					)
-				}
+				return util.NewContextualError("v2 certificate was added, restart required", nil, err)
 			}
 
-		} else if currentState.v2Cert != nil {
-			//newState.v1Cert is non-nil bc empty certstates aren't permitted
-			if newState.v1Cert == nil {
-				return util.NewContextualError("v1 and v2 certs are nil, this should be impossible", nil, err)
-			}
-			//if we're going to v1-only, we need to make sure we didn't orphan any v2-cert vpnaddrs
-			if !slices.Equal(currentState.v2Cert.Networks(), newState.v1Cert.Networks()) {
+			// did IP in cert change? if so, don't set
+			if !slices.Equal(currentState.v2Cert.Networks(), newState.v2Cert.Networks()) {
 				return util.NewContextualError(
-					"Removing a V2 cert is not permitted unless it has identical networks to the new V1 cert",
-					m{"new_v1_networks": newState.v1Cert.Networks(), "old_v2_networks": currentState.v2Cert.Networks()},
+					"Networks in new cert was different from old",
+					m{"new_networks": newState.v2Cert.Networks(), "old_networks": currentState.v2Cert.Networks()},
 					nil,
 				)
 			}
+
+			if currentState.v2Cert.Curve() != newState.v2Cert.Curve() {
+				return util.NewContextualError(
+					"Curve in new cert was different from old",
+					m{"new_curve": newState.v2Cert.Curve(), "old_curve": currentState.v2Cert.Curve()},
+					nil,
+				)
+			}
+
+		} else if currentState.v2Cert != nil {
+			return util.NewContextualError("v2 certificate was removed, restart required", nil, err)
 		}
 
 		// Cipher cant be hot swapped so just leave it at what it was before

udp/config.go

@@ -0,0 +1,16 @@
+package udp
+
+import "sync/atomic"
+
+var disableUDPCsum atomic.Bool
+
+// SetDisableUDPCsum controls whether IPv4 UDP sockets opt out of kernel
+// checksum calculation via SO_NO_CHECK. Only applicable on platforms that
+// support the option (Linux). IPv6 always keeps the checksum enabled.
+func SetDisableUDPCsum(disable bool) {
+	disableUDPCsum.Store(disable)
+}
+
+func udpChecksumDisabled() bool {
+	return disableUDPCsum.Load()
+}

udp/conn.go

@@ -11,6 +11,7 @@ const MTU = 9001
 type EncReader func(
 	addr netip.AddrPort,
 	payload []byte,
+	release func(),
 )
 
 type Conn interface {
@@ -22,18 +23,6 @@ type Conn interface {
 	Close() error
 }
 
-// Datagram represents a UDP payload destined to a specific address.
-type Datagram struct {
-	Payload []byte
-	Addr    netip.AddrPort
-}
-
-// BatchConn can send multiple datagrams in one syscall.
-type BatchConn interface {
-	Conn
-	WriteBatch(pkts []Datagram) error
-}
-
 type NoopConn struct{}
 
 func (NoopConn) Rebind() error {

udp/msghdr_helper_linux_32.go

@@ -0,0 +1,25 @@
+//go:build linux && (386 || amd64p32 || arm || mips || mipsle) && !android && !e2e_testing
+// +build linux
+// +build 386 amd64p32 arm mips mipsle
+// +build !android
+// +build !e2e_testing
+
+package udp
+
+import "golang.org/x/sys/unix"
+
+func controllen(n int) uint32 {
+	return uint32(n)
+}
+
+func setCmsgLen(h *unix.Cmsghdr, n int) {
+	h.Len = uint32(unix.CmsgLen(n))
+}
+
+func setIovecLen(v *unix.Iovec, n int) {
+	v.Len = uint32(n)
+}
+
+func setMsghdrIovlen(m *unix.Msghdr, n int) {
+	m.Iovlen = uint32(n)
+}

udp/msghdr_helper_linux_64.go

@@ -0,0 +1,25 @@
+//go:build linux && (amd64 || arm64 || ppc64 || ppc64le || mips64 || mips64le || s390x || riscv64 || loong64) && !android && !e2e_testing
+// +build linux
+// +build amd64 arm64 ppc64 ppc64le mips64 mips64le s390x riscv64 loong64
+// +build !android
+// +build !e2e_testing
+
+package udp
+
+import "golang.org/x/sys/unix"
+
+func controllen(n int) uint64 {
+	return uint64(n)
+}
+
+func setCmsgLen(h *unix.Cmsghdr, n int) {
+	h.Len = uint64(unix.CmsgLen(n))
+}
+
+func setIovecLen(v *unix.Iovec, n int) {
+	v.Len = uint64(n)
+}
+
+func setMsghdrIovlen(m *unix.Msghdr, n int) {
+	m.Iovlen = uint64(n)
+}

udp/sendmmsg_linux_32.go

@@ -0,0 +1,25 @@
+//go:build linux && (386 || amd64p32 || arm || mips || mipsle) && !android && !e2e_testing
+
+package udp
+
+import (
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+type linuxMmsgHdr struct {
+	Hdr unix.Msghdr
+	Len uint32
+}
+
+func sendmmsg(fd int, hdrs []linuxMmsgHdr, flags int) (int, error) {
+	if len(hdrs) == 0 {
+		return 0, nil
+	}
+	n, _, errno := unix.Syscall6(unix.SYS_SENDMMSG, uintptr(fd), uintptr(unsafe.Pointer(&hdrs[0])), uintptr(len(hdrs)), uintptr(flags), 0, 0)
+	if errno != 0 {
+		return int(n), errno
+	}
+	return int(n), nil
+}

udp/sendmmsg_linux_64.go

@@ -0,0 +1,26 @@
+//go:build linux && (amd64 || arm64 || ppc64 || ppc64le || mips64 || mips64le || s390x || riscv64 || loong64) && !android && !e2e_testing
+
+package udp
+
+import (
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+type linuxMmsgHdr struct {
+	Hdr unix.Msghdr
+	Len uint32
+	_   uint32
+}
+
+func sendmmsg(fd int, hdrs []linuxMmsgHdr, flags int) (int, error) {
+	if len(hdrs) == 0 {
+		return 0, nil
+	}
+	n, _, errno := unix.Syscall6(unix.SYS_SENDMMSG, uintptr(fd), uintptr(unsafe.Pointer(&hdrs[0])), uintptr(len(hdrs)), uintptr(flags), 0, 0)
+	if errno != 0 {
+		return int(n), errno
+	}
+	return int(n), nil
+}

udp/udp_darwin.go

@@ -180,7 +180,7 @@ func (u *StdConn) ListenOut(r EncReader) {
 			u.l.WithError(err).Error("unexpected udp socket receive error")
 		}
 
-		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n])
+		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n], nil)
 	}
 }
 

udp/udp_generic.go

@@ -82,6 +82,6 @@ func (u *GenericConn) ListenOut(r EncReader) {
 			return
 		}
 
-		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n])
+		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n], nil)
 	}
 }

udp/udp_linux_32.go

@@ -30,17 +30,29 @@ type rawMessage struct {
 	Len uint32
 }
 
-func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]byte, [][]byte) {
+func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]byte, [][]byte, [][]byte) {
+	controlLen := int(u.controlLen.Load())
+
 	msgs := make([]rawMessage, n)
 	buffers := make([][]byte, n)
 	names := make([][]byte, n)
 
+	var controls [][]byte
+	if controlLen > 0 {
+		controls = make([][]byte, n)
+	}
+
 	for i := range msgs {
-		buffers[i] = make([]byte, MTU)
+		size := int(u.groBufSize.Load())
+		if size < MTU {
+			size = MTU
+		}
+		buf := u.borrowRxBuffer(size)
+		buffers[i] = buf
 		names[i] = make([]byte, unix.SizeofSockaddrInet6)
 
 		vs := []iovec{
-			{Base: &buffers[i][0], Len: uint32(len(buffers[i]))},
+			{Base: &buf[0], Len: uint32(len(buf))},
 		}
 
 		msgs[i].Hdr.Iov = &vs[0]
@@ -48,7 +60,22 @@ func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]byte, [][]byte) {
 
 		msgs[i].Hdr.Name = &names[i][0]
 		msgs[i].Hdr.Namelen = uint32(len(names[i]))
+
+		if controlLen > 0 {
+			controls[i] = make([]byte, controlLen)
+			msgs[i].Hdr.Control = &controls[i][0]
+			msgs[i].Hdr.Controllen = controllen(len(controls[i]))
+		} else {
+			msgs[i].Hdr.Control = nil
+			msgs[i].Hdr.Controllen = controllen(0)
+		}
 	}
 
-	return msgs, buffers, names
+	return msgs, buffers, names, controls
+}
+
+func setIovecBase(msg *rawMessage, buf []byte) {
+	iov := (*iovec)(msg.Hdr.Iov)
+	iov.Base = &buf[0]
+	iov.Len = uint32(len(buf))
 }

udp/udp_linux_64.go

@@ -33,25 +33,50 @@ type rawMessage struct {
 	Pad0 [4]byte
 }
 
-func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]byte, [][]byte) {
+func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]byte, [][]byte, [][]byte) {
+	controlLen := int(u.controlLen.Load())
+
 	msgs := make([]rawMessage, n)
 	buffers := make([][]byte, n)
 	names := make([][]byte, n)
 
+	var controls [][]byte
+	if controlLen > 0 {
+		controls = make([][]byte, n)
+	}
+
 	for i := range msgs {
-		buffers[i] = make([]byte, MTU)
+		size := int(u.groBufSize.Load())
+		if size < MTU {
+			size = MTU
+		}
+		buf := u.borrowRxBuffer(size)
+		buffers[i] = buf
 		names[i] = make([]byte, unix.SizeofSockaddrInet6)
 
-		vs := []iovec{
-			{Base: &buffers[i][0], Len: uint64(len(buffers[i]))},
-		}
+		vs := []iovec{{Base: &buf[0], Len: uint64(len(buf))}}
 
 		msgs[i].Hdr.Iov = &vs[0]
 		msgs[i].Hdr.Iovlen = uint64(len(vs))
 
 		msgs[i].Hdr.Name = &names[i][0]
 		msgs[i].Hdr.Namelen = uint32(len(names[i]))
+
+		if controlLen > 0 {
+			controls[i] = make([]byte, controlLen)
+			msgs[i].Hdr.Control = &controls[i][0]
+			msgs[i].Hdr.Controllen = controllen(len(controls[i]))
+		} else {
+			msgs[i].Hdr.Control = nil
+			msgs[i].Hdr.Controllen = controllen(0)
+		}
 	}
 
-	return msgs, buffers, names
+	return msgs, buffers, names, controls
+}
+
+func setIovecBase(msg *rawMessage, buf []byte) {
+	iov := (*iovec)(msg.Hdr.Iov)
+	iov.Base = &buf[0]
+	iov.Len = uint64(len(buf))
 }

udp/udp_rio_windows.go

@@ -149,7 +149,7 @@ func (u *RIOConn) ListenOut(r EncReader) {
 			continue
 		}
 
-		r(netip.AddrPortFrom(netip.AddrFrom16(rua.Addr).Unmap(), (rua.Port>>8)|((rua.Port&0xff)<<8)), buffer[:n])
+		r(netip.AddrPortFrom(netip.AddrFrom16(rua.Addr).Unmap(), (rua.Port>>8)|((rua.Port&0xff)<<8)), buffer[:n], nil)
 	}
 }
 

udp/udp_tester.go

@@ -112,7 +112,7 @@ func (u *TesterConn) ListenOut(r EncReader) {
 		if !ok {
 			return
 		}
-		r(p.From, p.Data)
+		r(p.From, p.Data, func() {})
 	}
 }
 

udp/wireguard_conn_linux.go

@@ -1,226 +0,0 @@
-//go:build linux && !android && !e2e_testing
-
-package udp
-
-import (
-	"errors"
-	"net"
-	"net/netip"
-	"sync"
-	"sync/atomic"
-
-	"github.com/sirupsen/logrus"
-	"github.com/slackhq/nebula/config"
-	wgconn "github.com/slackhq/nebula/wgstack/conn"
-)
-
-// WGConn adapts WireGuard's batched UDP bind implementation to Nebula's udp.Conn interface.
-type WGConn struct {
-	l         *logrus.Logger
-	bind      *wgconn.StdNetBind
-	recvers   []wgconn.ReceiveFunc
-	batch     int
-	reqBatch  int
-	localIP   netip.Addr
-	localPort uint16
-	enableGSO bool
-	enableGRO bool
-	gsoMaxSeg int
-	closed    atomic.Bool
-	q         int
-	closeOnce sync.Once
-}
-
-// NewWireguardListener creates a UDP listener backed by WireGuard's StdNetBind.
-func NewWireguardListener(l *logrus.Logger, ip netip.Addr, port int, multi bool, batch int, q int) (Conn, error) {
-	bind := wgconn.NewStdNetBindForAddr(ip, multi, q)
-	recvers, actualPort, err := bind.Open(uint16(port))
-	if err != nil {
-		return nil, err
-	}
-	if batch <= 0 {
-		batch = bind.BatchSize()
-	} else if batch > bind.BatchSize() {
-		batch = bind.BatchSize()
-	}
-	return &WGConn{
-		l:         l,
-		bind:      bind,
-		recvers:   recvers,
-		batch:     batch,
-		reqBatch:  batch,
-		localIP:   ip,
-		localPort: actualPort,
-		q:         q,
-	}, nil
-}
-
-func (c *WGConn) Rebind() error {
-	// WireGuard's bind does not support rebinding in place.
-	return nil
-}
-
-func (c *WGConn) LocalAddr() (netip.AddrPort, error) {
-	if !c.localIP.IsValid() || c.localIP.IsUnspecified() {
-		// Fallback to wildcard IPv4 for display purposes.
-		return netip.AddrPortFrom(netip.IPv4Unspecified(), c.localPort), nil
-	}
-	return netip.AddrPortFrom(c.localIP, c.localPort), nil
-}
-
-func (c *WGConn) listen(fn wgconn.ReceiveFunc, r EncReader) {
-	batchSize := c.batch
-	packets := make([][]byte, batchSize)
-	for i := range packets {
-		packets[i] = make([]byte, 0xffff)
-	}
-	sizes := make([]int, batchSize)
-	endpoints := make([]wgconn.Endpoint, batchSize)
-
-	for {
-		if c.closed.Load() {
-			return
-		}
-		n, err := fn(packets, sizes, endpoints)
-		if err != nil {
-			if errors.Is(err, net.ErrClosed) {
-				return
-			}
-			if c.l != nil {
-				c.l.WithError(err).Debug("wireguard UDP listener receive error")
-			}
-			continue
-		}
-		for i := 0; i < n; i++ {
-			if sizes[i] == 0 {
-				continue
-			}
-			stdEp, ok := endpoints[i].(*wgconn.StdNetEndpoint)
-			if !ok {
-				if c.l != nil {
-					c.l.Warn("wireguard UDP listener received unexpected endpoint type")
-				}
-				continue
-			}
-			addr := stdEp.AddrPort
-			r(addr, packets[i][:sizes[i]])
-			endpoints[i] = nil
-		}
-	}
-}
-
-func (c *WGConn) ListenOut(r EncReader) {
-	for _, fn := range c.recvers {
-		go c.listen(fn, r)
-	}
-}
-
-func (c *WGConn) WriteTo(b []byte, addr netip.AddrPort) error {
-	if len(b) == 0 {
-		return nil
-	}
-	if c.closed.Load() {
-		return net.ErrClosed
-	}
-	ep := &wgconn.StdNetEndpoint{AddrPort: addr}
-	return c.bind.Send([][]byte{b}, ep)
-}
-
-func (c *WGConn) WriteBatch(datagrams []Datagram) error {
-	if len(datagrams) == 0 {
-		return nil
-	}
-	if c.closed.Load() {
-		return net.ErrClosed
-	}
-	max := c.batch
-	if max <= 0 {
-		max = len(datagrams)
-		if max == 0 {
-			max = 1
-		}
-	}
-	bufs := make([][]byte, 0, max)
-	var (
-		current  netip.AddrPort
-		endpoint *wgconn.StdNetEndpoint
-		haveAddr bool
-	)
-	flush := func() error {
-		if len(bufs) == 0 || endpoint == nil {
-			bufs = bufs[:0]
-			return nil
-		}
-		err := c.bind.Send(bufs, endpoint)
-		bufs = bufs[:0]
-		return err
-	}
-
-	for _, d := range datagrams {
-		if len(d.Payload) == 0 || !d.Addr.IsValid() {
-			continue
-		}
-		if !haveAddr || d.Addr != current {
-			if err := flush(); err != nil {
-				return err
-			}
-			current = d.Addr
-			endpoint = &wgconn.StdNetEndpoint{AddrPort: current}
-			haveAddr = true
-		}
-		bufs = append(bufs, d.Payload)
-		if len(bufs) >= max {
-			if err := flush(); err != nil {
-				return err
-			}
-		}
-	}
-	return flush()
-}
-
-func (c *WGConn) ConfigureOffload(enableGSO, enableGRO bool, maxSegments int) {
-	c.enableGSO = enableGSO
-	c.enableGRO = enableGRO
-	if maxSegments <= 0 {
-		maxSegments = 1
-	} else if maxSegments > wgconn.IdealBatchSize {
-		maxSegments = wgconn.IdealBatchSize
-	}
-	c.gsoMaxSeg = maxSegments
-
-	effectiveBatch := c.reqBatch
-	if enableGSO && c.bind != nil {
-		bindBatch := c.bind.BatchSize()
-		if effectiveBatch < bindBatch {
-			if c.l != nil {
-				c.l.WithFields(logrus.Fields{
-					"requested": c.reqBatch,
-					"effective": bindBatch,
-				}).Warn("listen.batch below wireguard minimum; using bind batch size for UDP GSO support")
-			}
-			effectiveBatch = bindBatch
-		}
-	}
-	c.batch = effectiveBatch
-
-	if c.l != nil {
-		c.l.WithFields(logrus.Fields{
-			"enableGSO":      enableGSO,
-			"enableGRO":      enableGRO,
-			"gsoMaxSegments": maxSegments,
-		}).Debug("configured wireguard UDP offload")
-	}
-}
-
-func (c *WGConn) ReloadConfig(*config.C) {
-	// WireGuard bind currently does not expose runtime configuration knobs.
-}
-
-func (c *WGConn) Close() error {
-	var err error
-	c.closeOnce.Do(func() {
-		c.closed.Store(true)
-		err = c.bind.Close()
-	})
-	return err
-}

udp/wireguard_conn_unsupported.go

@@ -1,15 +0,0 @@
-//go:build !linux || android || e2e_testing
-
-package udp
-
-import (
-	"fmt"
-	"net/netip"
-
-	"github.com/sirupsen/logrus"
-)
-
-// NewWireguardListener is only available on Linux builds.
-func NewWireguardListener(*logrus.Logger, netip.Addr, int, bool, int) (Conn, error) {
-	return nil, fmt.Errorf("wireguard experimental UDP listener is only supported on Linux")
-}

wgstack/conn/bind_std.go

@@ -1,587 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-import (
-	"context"
-	"errors"
-	"fmt"
-	"net"
-	"net/netip"
-	"runtime"
-	"strconv"
-	"sync"
-	"syscall"
-
-	"golang.org/x/net/ipv4"
-	"golang.org/x/net/ipv6"
-)
-
-var (
-	_ Bind = (*StdNetBind)(nil)
-)
-
-// StdNetBind implements Bind for all platforms. While Windows has its own Bind
-// (see bind_windows.go), it may fall back to StdNetBind.
-// TODO: Remove usage of ipv{4,6}.PacketConn when net.UDPConn has comparable
-// methods for sending and receiving multiple datagrams per-syscall. See the
-// proposal in https://github.com/golang/go/issues/45886#issuecomment-1218301564.
-type StdNetBind struct {
-	mu            sync.Mutex // protects all fields except as specified
-	ipv4          *net.UDPConn
-	ipv6          *net.UDPConn
-	ipv4PC        *ipv4.PacketConn // will be nil on non-Linux
-	ipv6PC        *ipv6.PacketConn // will be nil on non-Linux
-	ipv4TxOffload bool
-	ipv4RxOffload bool
-	ipv6TxOffload bool
-	ipv6RxOffload bool
-
-	// these two fields are not guarded by mu
-	udpAddrPool sync.Pool
-	msgsPool    sync.Pool
-
-	blackhole4 bool
-	blackhole6 bool
-	q          int
-}
-
-// NewStdNetBind creates a bind that listens on all interfaces.
-func NewStdNetBind() *StdNetBind {
-	return newStdNetBind().(*StdNetBind)
-}
-
-// NewStdNetBindForAddr creates a bind that listens on a specific address.
-// If addr is IPv4, only the IPv4 socket will be created. For IPv6, only the
-// IPv6 socket will be created.
-func NewStdNetBindForAddr(addr netip.Addr, reusePort bool, q int) *StdNetBind {
-	b := NewStdNetBind()
-	b.q = q
-	//if addr.IsValid() {
-	//	if addr.IsUnspecified() {
-	//		// keep dual-stack defaults with empty listen addresses
-	//	} else if addr.Is4() {
-	//		b.listenAddr4 = addr.Unmap().String()
-	//		b.bindV4 = true
-	//		b.bindV6 = false
-	//	} else {
-	//		b.listenAddr6 = addr.Unmap().String()
-	//		b.bindV6 = true
-	//		b.bindV4 = false
-	//	}
-	//}
-	//b.reusePort = reusePort
-
-	return b
-}
-
-func newStdNetBind() Bind {
-	return &StdNetBind{
-		udpAddrPool: sync.Pool{
-			New: func() any {
-				return &net.UDPAddr{
-					IP: make([]byte, 16),
-				}
-			},
-		},
-
-		msgsPool: sync.Pool{
-			New: func() any {
-				// ipv6.Message and ipv4.Message are interchangeable as they are
-				// both aliases for x/net/internal/socket.Message.
-				msgs := make([]ipv6.Message, IdealBatchSize)
-				for i := range msgs {
-					msgs[i].Buffers = make(net.Buffers, 1)
-					msgs[i].OOB = make([]byte, 0, stickyControlSize+gsoControlSize)
-				}
-				return &msgs
-			},
-		},
-	}
-}
-
-type StdNetEndpoint struct {
-	// AddrPort is the endpoint destination.
-	netip.AddrPort
-	// src is the current sticky source address and interface index, if
-	// supported. Typically this is a PKTINFO structure from/for control
-	// messages, see unix.PKTINFO for an example.
-	src []byte
-}
-
-var (
-	_ Bind     = (*StdNetBind)(nil)
-	_ Endpoint = &StdNetEndpoint{}
-)
-
-func (*StdNetBind) ParseEndpoint(s string) (Endpoint, error) {
-	e, err := netip.ParseAddrPort(s)
-	if err != nil {
-		return nil, err
-	}
-	return &StdNetEndpoint{
-		AddrPort: e,
-	}, nil
-}
-
-func (e *StdNetEndpoint) ClearSrc() {
-	if e.src != nil {
-		// Truncate src, no need to reallocate.
-		e.src = e.src[:0]
-	}
-}
-
-func (e *StdNetEndpoint) DstIP() netip.Addr {
-	return e.AddrPort.Addr()
-}
-
-// See control_default,linux, etc for implementations of SrcIP and SrcIfidx.
-
-func (e *StdNetEndpoint) DstToBytes() []byte {
-	b, _ := e.AddrPort.MarshalBinary()
-	return b
-}
-
-func (e *StdNetEndpoint) DstToString() string {
-	return e.AddrPort.String()
-}
-
-func listenNet(network string, port int, q int) (*net.UDPConn, int, error) {
-	lc := listenConfig(q)
-
-	conn, err := lc.ListenPacket(context.Background(), network, ":"+strconv.Itoa(port))
-	if err != nil {
-		return nil, 0, err
-	}
-
-	if q == 0 {
-		if EvilFdZero == 0 {
-			panic("fuck")
-		}
-		err = reusePortHax(EvilFdZero)
-		if err != nil {
-			return nil, 0, fmt.Errorf("reuse port hax: %v", err)
-		}
-	}
-
-	// Retrieve port.
-	laddr := conn.LocalAddr()
-	uaddr, err := net.ResolveUDPAddr(
-		laddr.Network(),
-		laddr.String(),
-	)
-	if err != nil {
-		return nil, 0, err
-	}
-
-	return conn.(*net.UDPConn), uaddr.Port, nil
-}
-
-func (s *StdNetBind) Open(uport uint16) ([]ReceiveFunc, uint16, error) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
-	var err error
-	var tries int
-
-	if s.ipv4 != nil || s.ipv6 != nil {
-		return nil, 0, ErrBindAlreadyOpen
-	}
-
-	// Attempt to open ipv4 and ipv6 listeners on the same port.
-	// If uport is 0, we can retry on failure.
-again:
-	port := int(uport)
-	var v4conn, v6conn *net.UDPConn
-	var v4pc *ipv4.PacketConn
-	var v6pc *ipv6.PacketConn
-
-	v4conn, port, err = listenNet("udp4", port, s.q)
-	if err != nil && !errors.Is(err, syscall.EAFNOSUPPORT) {
-		return nil, 0, err
-	}
-
-	// Listen on the same port as we're using for ipv4.
-	v6conn, port, err = listenNet("udp6", port, s.q)
-	if uport == 0 && errors.Is(err, syscall.EADDRINUSE) && tries < 100 {
-		v4conn.Close()
-		tries++
-		goto again
-	}
-	if err != nil && !errors.Is(err, syscall.EAFNOSUPPORT) {
-		v4conn.Close()
-		return nil, 0, err
-	}
-	var fns []ReceiveFunc
-	if v4conn != nil {
-		s.ipv4TxOffload, s.ipv4RxOffload = supportsUDPOffload(v4conn)
-		if runtime.GOOS == "linux" || runtime.GOOS == "android" {
-			v4pc = ipv4.NewPacketConn(v4conn)
-			s.ipv4PC = v4pc
-		}
-		fns = append(fns, s.makeReceiveIPv4(v4pc, v4conn, s.ipv4RxOffload))
-		s.ipv4 = v4conn
-	}
-	if v6conn != nil {
-		s.ipv6TxOffload, s.ipv6RxOffload = supportsUDPOffload(v6conn)
-		if runtime.GOOS == "linux" || runtime.GOOS == "android" {
-			v6pc = ipv6.NewPacketConn(v6conn)
-			s.ipv6PC = v6pc
-		}
-		fns = append(fns, s.makeReceiveIPv6(v6pc, v6conn, s.ipv6RxOffload))
-		s.ipv6 = v6conn
-	}
-	if len(fns) == 0 {
-		return nil, 0, syscall.EAFNOSUPPORT
-	}
-
-	return fns, uint16(port), nil
-}
-
-func (s *StdNetBind) putMessages(msgs *[]ipv6.Message) {
-	for i := range *msgs {
-		(*msgs)[i].OOB = (*msgs)[i].OOB[:0]
-		(*msgs)[i] = ipv6.Message{Buffers: (*msgs)[i].Buffers, OOB: (*msgs)[i].OOB}
-	}
-	s.msgsPool.Put(msgs)
-}
-
-func (s *StdNetBind) getMessages() *[]ipv6.Message {
-	return s.msgsPool.Get().(*[]ipv6.Message)
-}
-
-var (
-	// If compilation fails here these are no longer the same underlying type.
-	_ ipv6.Message = ipv4.Message{}
-)
-
-type batchReader interface {
-	ReadBatch([]ipv6.Message, int) (int, error)
-}
-
-type batchWriter interface {
-	WriteBatch([]ipv6.Message, int) (int, error)
-}
-
-func (s *StdNetBind) receiveIP(
-	br batchReader,
-	conn *net.UDPConn,
-	rxOffload bool,
-	bufs [][]byte,
-	sizes []int,
-	eps []Endpoint,
-) (n int, err error) {
-	msgs := s.getMessages()
-	for i := range bufs {
-		(*msgs)[i].Buffers[0] = bufs[i]
-		(*msgs)[i].OOB = (*msgs)[i].OOB[:cap((*msgs)[i].OOB)]
-	}
-	defer s.putMessages(msgs)
-	var numMsgs int
-	if runtime.GOOS == "linux" || runtime.GOOS == "android" {
-		if rxOffload {
-			readAt := len(*msgs) - (IdealBatchSize / udpSegmentMaxDatagrams)
-			numMsgs, err = br.ReadBatch((*msgs)[readAt:], 0)
-			if err != nil {
-				return 0, err
-			}
-			numMsgs, err = splitCoalescedMessages(*msgs, readAt, getGSOSize)
-			if err != nil {
-				return 0, err
-			}
-		} else {
-			numMsgs, err = br.ReadBatch(*msgs, 0)
-			if err != nil {
-				return 0, err
-			}
-		}
-	} else {
-		msg := &(*msgs)[0]
-		msg.N, msg.NN, _, msg.Addr, err = conn.ReadMsgUDP(msg.Buffers[0], msg.OOB)
-		if err != nil {
-			return 0, err
-		}
-		numMsgs = 1
-	}
-	for i := 0; i < numMsgs; i++ {
-		msg := &(*msgs)[i]
-		sizes[i] = msg.N
-		if sizes[i] == 0 {
-			continue
-		}
-		addrPort := msg.Addr.(*net.UDPAddr).AddrPort()
-		ep := &StdNetEndpoint{AddrPort: addrPort} // TODO: remove allocation
-		getSrcFromControl(msg.OOB[:msg.NN], ep)
-		eps[i] = ep
-	}
-	return numMsgs, nil
-}
-
-func (s *StdNetBind) makeReceiveIPv4(pc *ipv4.PacketConn, conn *net.UDPConn, rxOffload bool) ReceiveFunc {
-	return func(bufs [][]byte, sizes []int, eps []Endpoint) (n int, err error) {
-		return s.receiveIP(pc, conn, rxOffload, bufs, sizes, eps)
-	}
-}
-
-func (s *StdNetBind) makeReceiveIPv6(pc *ipv6.PacketConn, conn *net.UDPConn, rxOffload bool) ReceiveFunc {
-	return func(bufs [][]byte, sizes []int, eps []Endpoint) (n int, err error) {
-		return s.receiveIP(pc, conn, rxOffload, bufs, sizes, eps)
-	}
-}
-
-// TODO: When all Binds handle IdealBatchSize, remove this dynamic function and
-// rename the IdealBatchSize constant to BatchSize.
-func (s *StdNetBind) BatchSize() int {
-	if runtime.GOOS == "linux" || runtime.GOOS == "android" {
-		return IdealBatchSize
-	}
-	return 1
-}
-
-func (s *StdNetBind) Close() error {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
-	var err1, err2 error
-	if s.ipv4 != nil {
-		err1 = s.ipv4.Close()
-		s.ipv4 = nil
-		s.ipv4PC = nil
-	}
-	if s.ipv6 != nil {
-		err2 = s.ipv6.Close()
-		s.ipv6 = nil
-		s.ipv6PC = nil
-	}
-	s.blackhole4 = false
-	s.blackhole6 = false
-	s.ipv4TxOffload = false
-	s.ipv4RxOffload = false
-	s.ipv6TxOffload = false
-	s.ipv6RxOffload = false
-	if err1 != nil {
-		return err1
-	}
-	return err2
-}
-
-type ErrUDPGSODisabled struct {
-	onLaddr  string
-	RetryErr error
-}
-
-func (e ErrUDPGSODisabled) Error() string {
-	return fmt.Sprintf("disabled UDP GSO on %s, NIC(s) may not support checksum offload", e.onLaddr)
-}
-
-func (e ErrUDPGSODisabled) Unwrap() error {
-	return e.RetryErr
-}
-
-func (s *StdNetBind) Send(bufs [][]byte, endpoint Endpoint) error {
-	s.mu.Lock()
-	blackhole := s.blackhole4
-	conn := s.ipv4
-	offload := s.ipv4TxOffload
-	br := batchWriter(s.ipv4PC)
-	is6 := false
-	if endpoint.DstIP().Is6() {
-		blackhole = s.blackhole6
-		conn = s.ipv6
-		br = s.ipv6PC
-		is6 = true
-		offload = s.ipv6TxOffload
-	}
-	s.mu.Unlock()
-
-	if blackhole {
-		return nil
-	}
-	if conn == nil {
-		return syscall.EAFNOSUPPORT
-	}
-
-	msgs := s.getMessages()
-	defer s.putMessages(msgs)
-	ua := s.udpAddrPool.Get().(*net.UDPAddr)
-	defer s.udpAddrPool.Put(ua)
-	if is6 {
-		as16 := endpoint.DstIP().As16()
-		copy(ua.IP, as16[:])
-		ua.IP = ua.IP[:16]
-	} else {
-		as4 := endpoint.DstIP().As4()
-		copy(ua.IP, as4[:])
-		ua.IP = ua.IP[:4]
-	}
-	ua.Port = int(endpoint.(*StdNetEndpoint).Port())
-	var (
-		retried bool
-		err     error
-	)
-retry:
-	if offload {
-		n := coalesceMessages(ua, endpoint.(*StdNetEndpoint), bufs, *msgs, setGSOSize)
-		err = s.send(conn, br, (*msgs)[:n])
-		if err != nil && offload && errShouldDisableUDPGSO(err) {
-			offload = false
-			s.mu.Lock()
-			if is6 {
-				s.ipv6TxOffload = false
-			} else {
-				s.ipv4TxOffload = false
-			}
-			s.mu.Unlock()
-			retried = true
-			goto retry
-		}
-	} else {
-		for i := range bufs {
-			(*msgs)[i].Addr = ua
-			(*msgs)[i].Buffers[0] = bufs[i]
-			setSrcControl(&(*msgs)[i].OOB, endpoint.(*StdNetEndpoint))
-		}
-		err = s.send(conn, br, (*msgs)[:len(bufs)])
-	}
-	if retried {
-		return ErrUDPGSODisabled{onLaddr: conn.LocalAddr().String(), RetryErr: err}
-	}
-	return err
-}
-
-func (s *StdNetBind) send(conn *net.UDPConn, pc batchWriter, msgs []ipv6.Message) error {
-	var (
-		n     int
-		err   error
-		start int
-	)
-	if runtime.GOOS == "linux" || runtime.GOOS == "android" {
-		for {
-			n, err = pc.WriteBatch(msgs[start:], 0)
-			if err != nil || n == len(msgs[start:]) {
-				break
-			}
-			start += n
-		}
-	} else {
-		for _, msg := range msgs {
-			_, _, err = conn.WriteMsgUDP(msg.Buffers[0], msg.OOB, msg.Addr.(*net.UDPAddr))
-			if err != nil {
-				break
-			}
-		}
-	}
-	return err
-}
-
-const (
-	// Exceeding these values results in EMSGSIZE. They account for layer3 and
-	// layer4 headers. IPv6 does not need to account for itself as the payload
-	// length field is self excluding.
-	maxIPv4PayloadLen = 1<<16 - 1 - 20 - 8
-	maxIPv6PayloadLen = 1<<16 - 1 - 8
-
-	// This is a hard limit imposed by the kernel.
-	udpSegmentMaxDatagrams = 64
-)
-
-type setGSOFunc func(control *[]byte, gsoSize uint16)
-
-func coalesceMessages(addr *net.UDPAddr, ep *StdNetEndpoint, bufs [][]byte, msgs []ipv6.Message, setGSO setGSOFunc) int {
-	var (
-		base     = -1 // index of msg we are currently coalescing into
-		gsoSize  int  // segmentation size of msgs[base]
-		dgramCnt int  // number of dgrams coalesced into msgs[base]
-		endBatch bool // tracking flag to start a new batch on next iteration of bufs
-	)
-	maxPayloadLen := maxIPv4PayloadLen
-	if ep.DstIP().Is6() {
-		maxPayloadLen = maxIPv6PayloadLen
-	}
-	for i, buf := range bufs {
-		if i > 0 {
-			msgLen := len(buf)
-			baseLenBefore := len(msgs[base].Buffers[0])
-			freeBaseCap := cap(msgs[base].Buffers[0]) - baseLenBefore
-			if msgLen+baseLenBefore <= maxPayloadLen &&
-				msgLen <= gsoSize &&
-				msgLen <= freeBaseCap &&
-				dgramCnt < udpSegmentMaxDatagrams &&
-				!endBatch {
-				msgs[base].Buffers[0] = append(msgs[base].Buffers[0], buf...)
-				if i == len(bufs)-1 {
-					setGSO(&msgs[base].OOB, uint16(gsoSize))
-				}
-				dgramCnt++
-				if msgLen < gsoSize {
-					// A smaller than gsoSize packet on the tail is legal, but
-					// it must end the batch.
-					endBatch = true
-				}
-				continue
-			}
-		}
-		if dgramCnt > 1 {
-			setGSO(&msgs[base].OOB, uint16(gsoSize))
-		}
-		// Reset prior to incrementing base since we are preparing to start a
-		// new potential batch.
-		endBatch = false
-		base++
-		gsoSize = len(buf)
-		setSrcControl(&msgs[base].OOB, ep)
-		msgs[base].Buffers[0] = buf
-		msgs[base].Addr = addr
-		dgramCnt = 1
-	}
-	return base + 1
-}
-
-type getGSOFunc func(control []byte) (int, error)
-
-func splitCoalescedMessages(msgs []ipv6.Message, firstMsgAt int, getGSO getGSOFunc) (n int, err error) {
-	for i := firstMsgAt; i < len(msgs); i++ {
-		msg := &msgs[i]
-		if msg.N == 0 {
-			return n, err
-		}
-		var (
-			gsoSize    int
-			start      int
-			end        = msg.N
-			numToSplit = 1
-		)
-		gsoSize, err = getGSO(msg.OOB[:msg.NN])
-		if err != nil {
-			return n, err
-		}
-		if gsoSize > 0 {
-			numToSplit = (msg.N + gsoSize - 1) / gsoSize
-			end = gsoSize
-		}
-		for j := 0; j < numToSplit; j++ {
-			if n > i {
-				return n, errors.New("splitting coalesced packet resulted in overflow")
-			}
-			copied := copy(msgs[n].Buffers[0], msg.Buffers[0][start:end])
-			msgs[n].N = copied
-			msgs[n].Addr = msg.Addr
-			start = end
-			end += gsoSize
-			if end > msg.N {
-				end = msg.N
-			}
-			n++
-		}
-		if i != n-1 {
-			// It is legal for bytes to move within msg.Buffers[0] as a result
-			// of splitting, so we only zero the source msg len when it is not
-			// the destination of the last split operation above.
-			msg.N = 0
-		}
-	}
-	return n, nil
-}

wgstack/conn/conn.go

@@ -1,131 +0,0 @@
-// SPDX-License-Identifier: MIT
-//
-// Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
-
-package conn
-
-import (
-	"errors"
-	"fmt"
-	"net/netip"
-	"reflect"
-	"runtime"
-	"strings"
-)
-
-const (
-	IdealBatchSize = 128 // maximum number of packets handled per read and write
-)
-
-// A ReceiveFunc receives at least one packet from the network and writes them
-// into packets. On a successful read it returns the number of elements of
-// sizes, packets, and endpoints that should be evaluated. Some elements of
-// sizes may be zero, and callers should ignore them. Callers must pass a sizes
-// and eps slice with a length greater than or equal to the length of packets.
-// These lengths must not exceed the length of the associated Bind.BatchSize().
-type ReceiveFunc func(packets [][]byte, sizes []int, eps []Endpoint) (n int, err error)
-
-// A Bind listens on a port for both IPv6 and IPv4 UDP traffic.
-//
-// A Bind interface may also be a PeekLookAtSocketFd or BindSocketToInterface,
-// depending on the platform-specific implementation.
-type Bind interface {
-	// Open puts the Bind into a listening state on a given port and reports the actual
-	// port that it bound to. Passing zero results in a random selection.
-	// fns is the set of functions that will be called to receive packets.
-	Open(port uint16) (fns []ReceiveFunc, actualPort uint16, err error)
-
-	// Close closes the Bind listener.
-	// All fns returned by Open must return net.ErrClosed after a call to Close.
-	Close() error
-
-	// SetMark sets the mark for each packet sent through this Bind.
-	// This mark is passed to the kernel as the socket option SO_MARK.
-	SetMark(mark uint32) error
-
-	// Send writes one or more packets in bufs to address ep. The length of
-	// bufs must not exceed BatchSize().
-	Send(bufs [][]byte, ep Endpoint) error
-
-	// ParseEndpoint creates a new endpoint from a string.
-	ParseEndpoint(s string) (Endpoint, error)
-
-	// BatchSize is the number of buffers expected to be passed to
-	// the ReceiveFuncs, and the maximum expected to be passed to SendBatch.
-	BatchSize() int
-}
-
-// BindSocketToInterface is implemented by Bind objects that support being
-// tied to a single network interface. Used by wireguard-windows.
-type BindSocketToInterface interface {
-	BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error
-	BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error
-}
-
-// PeekLookAtSocketFd is implemented by Bind objects that support having their
-// file descriptor peeked at. Used by wireguard-android.
-type PeekLookAtSocketFd interface {
-	PeekLookAtSocketFd4() (fd int, err error)
-	PeekLookAtSocketFd6() (fd int, err error)
-}
-
-// An Endpoint maintains the source/destination caching for a peer.
-//
-//	dst: the remote address of a peer ("endpoint" in uapi terminology)
-//	src: the local address from which datagrams originate going to the peer
-type Endpoint interface {
-	ClearSrc()           // clears the source address
-	SrcToString() string // returns the local source address (ip:port)
-	DstToString() string // returns the destination address (ip:port)
-	DstToBytes() []byte  // used for mac2 cookie calculations
-	DstIP() netip.Addr
-	SrcIP() netip.Addr
-}
-
-var (
-	ErrBindAlreadyOpen   = errors.New("bind is already open")
-	ErrWrongEndpointType = errors.New("endpoint type does not correspond with bind type")
-)
-
-func (fn ReceiveFunc) PrettyName() string {
-	name := runtime.FuncForPC(reflect.ValueOf(fn).Pointer()).Name()
-	// 0. cheese/taco.beansIPv6.func12.func21218-fm
-	name = strings.TrimSuffix(name, "-fm")
-	// 1. cheese/taco.beansIPv6.func12.func21218
-	if idx := strings.LastIndexByte(name, '/'); idx != -1 {
-		name = name[idx+1:]
-		// 2. taco.beansIPv6.func12.func21218
-	}
-	for {
-		var idx int
-		for idx = len(name) - 1; idx >= 0; idx-- {
-			if name[idx] < '0' || name[idx] > '9' {
-				break
-			}
-		}
-		if idx == len(name)-1 {
-			break
-		}
-		const dotFunc = ".func"
-		if !strings.HasSuffix(name[:idx+1], dotFunc) {
-			break
-		}
-		name = name[:idx+1-len(dotFunc)]
-		// 3. taco.beansIPv6.func12
-		// 4. taco.beansIPv6
-	}
-	if idx := strings.LastIndexByte(name, '.'); idx != -1 {
-		name = name[idx+1:]
-		// 5. beansIPv6
-	}
-	if name == "" {
-		return fmt.Sprintf("%p", fn)
-	}
-	if strings.HasSuffix(name, "IPv4") {
-		return "v4"
-	}
-	if strings.HasSuffix(name, "IPv6") {
-		return "v6"
-	}
-	return name
-}

wgstack/conn/controlfns.go

@@ -1,222 +0,0 @@
-// SPDX-License-Identifier: MIT
-//
-// Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
-
-package conn
-
-import (
-	"fmt"
-	"net"
-	"syscall"
-
-	"github.com/cilium/ebpf"
-	"github.com/cilium/ebpf/asm"
-)
-
-// UDP socket read/write buffer size (7MB). The value of 7MB is chosen as it is
-// the max supported by a default configuration of macOS. Some platforms will
-// silently clamp the value to other maximums, such as linux clamping to
-// net.core.{r,w}mem_max (see _linux.go for additional implementation that works
-// around this limitation)
-const socketBufferSize = 7 << 20
-
-// controlFn is the callback function signature from net.ListenConfig.Control.
-// It is used to apply platform specific configuration to the socket prior to
-// bind.
-type controlFn func(network, address string, c syscall.RawConn) error
-
-// controlFns is a list of functions that are called from the listen config
-// that can apply socket options.
-var controlFns = []controlFn{}
-
-const SO_ATTACH_REUSEPORT_EBPF = 52
-
-//Create eBPF program that returns a hash to distribute packets
-
-func createReuseportProgram() (*ebpf.Program, error) {
-	// This program uses the packet's hash and returns it modulo number of sockets
-	// Simple version: just return a counter-based distribution
-	//instructions := asm.Instructions{
-	//	// Load the skb->hash value (already computed by kernel)
-	//	asm.LoadMem(asm.R0, asm.R1, int16(unsafe.Offsetof(unix.XDPMd{}.RxQueueIndex)), asm.Word),
-	//	asm.Return(),
-	//}
-	//
-	//// Alternative: simpler round-robin approach
-	//// This returns the CPU number, effectively round-robin
-	//instructions := asm.Instructions{
-	//	asm.Mov.Reg(asm.R0, asm.R1),              // Move ctx to R0
-	//	asm.LoadMem(asm.R0, asm.R1, 0, asm.Word), // Load some field
-	//	asm.Return(),
-	//}
-
-	// Better: Use BPF helper to get random/hash value
-	//instructions := asm.Instructions{
-	//	// Call get_prandom_u32() to get random value for distribution
-	//	asm.Mov.Imm(asm.R0, 0),
-	//	asm.Call.Label("get_prandom_u32"),
-	//	asm.Return(),
-	//}
-	//
-	//prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
-	//	Type:         ebpf.SocketFilter,
-	//	Instructions: instructions,
-	//	License:      "GPL",
-	//})
-
-	//instructions := asm.Instructions{
-	//	// R1 contains pointer to skb
-	//	// Load skb->hash at offset 0x20 (may vary by kernel, but 0x20 is common)
-	//	asm.LoadMem(asm.R0, asm.R1, 0x20, asm.Word),
-	//
-	//	// If hash is 0, use rxhash instead (fallback)
-	//	asm.JEq.Imm(asm.R0, 0, "use_rxhash"),
-	//	asm.Return().Sym("return"),
-	//
-	//	// Fallback: load rxhash
-	//	asm.LoadMem(asm.R0, asm.R1, 0x24, asm.Word).Sym("use_rxhash"),
-	//	asm.Return(),
-	//}
-	//
-	//prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
-	//	Type:         ebpf.SkReuseport,
-	//	Instructions: instructions,
-	//	License:      "GPL",
-	//})
-
-	//instructions := asm.Instructions{
-	//	// R1 = ctx (sk_reuseport_md)
-	//	// R2 = sk_reuseport map (we'll use NULL/0 for default behavior)
-	//	// R3 = key (select socket index)
-	//	// R4 = flags
-	//
-	//	// Simple approach: use the hash field from sk_reuseport_md
-	//	// struct sk_reuseport_md { ... __u32 hash; ... } at offset 24
-	//	asm.Mov.Reg(asm.R6, asm.R1), // Save ctx
-	//
-	//	// Load the hash value at offset 24
-	//	asm.LoadMem(asm.R2, asm.R6, 24, asm.Word),
-	//
-	//	// Call bpf_sk_select_reuseport(ctx, map, key, flags)
-	//	asm.Mov.Reg(asm.R1, asm.R6), // ctx
-	//	asm.Mov.Imm(asm.R2, 0),      // map (NULL = use default)
-	//	asm.Mov.Reg(asm.R3, asm.R2), // key = hash we loaded (in R2)
-	//	asm.Mov.Imm(asm.R4, 0),      // flags
-	//	asm.Call.Label("sk_select_reuseport"),
-	//
-	//	// Return 0
-	//	asm.Mov.Imm(asm.R0, 0),
-	//	asm.Return(),
-	//}
-	//
-	//prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
-	//	Type:         ebpf.SkReuseport,
-	//	Instructions: instructions,
-	//	License:      "GPL",
-	//})
-
-	instructions := asm.Instructions{
-		// R1 = ctx (sk_reuseport_md pointer)
-		// Load hash from sk_reuseport_md at offset 24
-		//asm.LoadMem(asm.R0, asm.R1, 20, asm.Word),
-
-		// R1 = ctx (save it)
-		asm.Mov.Reg(asm.R6, asm.R1),
-
-		// Prepare string on stack: "BPF called!\n"
-		// We need to build the format string on the stack
-		asm.Mov.Reg(asm.R1, asm.R10), // R1 = frame pointer
-		asm.Add.Imm(asm.R1, -16),     // R1 = stack location for string
-
-		// Write "BPF called!\n" to stack (we'll use a simpler version)
-		// Store immediate 64-bit values
-		asm.StoreImm(asm.R1, 0, 0x2066706220, asm.DWord), // "bpf "
-		asm.StoreImm(asm.R1, 8, 0x0a21, asm.DWord),       // "!\n"
-
-		// Call bpf_trace_printk(fmt, fmt_size)
-		// R1 already points to format string
-		asm.Mov.Imm(asm.R2, 16), // R2 = format size
-		asm.Call.Label("bpf_printk"),
-
-		// Return 0 (send to socket 0 for testing)
-		asm.Mov.Imm(asm.R0, 0),
-		asm.Return(),
-
-		//asm.Mov.Imm(asm.R0, 0),
-		//// Just return the hash directly
-		//// The kernel will automatically modulo by number of sockets
-		//asm.Return(),
-	}
-
-	prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
-		Type:         ebpf.SkReuseport,
-		Instructions: instructions,
-		License:      "GPL",
-	})
-
-	return prog, err
-}
-
-//func createReuseportProgram() (*ebpf.Program, error) {
-//	// Try offset 20 (common in newer kernels)
-//	instructions := asm.Instructions{
-//		asm.LoadMem(asm.R0, asm.R1, 20, asm.Word),
-//		asm.Return(),
-//	}
-//
-//	prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
-//		Type:         ebpf.SkReuseport,
-//		Instructions: instructions,
-//		License:      "GPL",
-//	})
-//
-//	return prog, err
-//}
-
-func reusePortHax(fd uintptr) error {
-	prog, err := createReuseportProgram()
-	if err != nil {
-		return fmt.Errorf("failed to create eBPF program: %w", err)
-	}
-	//defer prog.Close()
-	sockErr := syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF, prog.FD())
-	if sockErr != nil {
-		return sockErr
-	}
-	return nil
-}
-
-var EvilFdZero uintptr
-
-// listenConfig returns a net.ListenConfig that applies the controlFns to the
-// socket prior to bind. This is used to apply socket buffer sizing and packet
-// information OOB configuration for sticky sockets.
-func listenConfig(q int) *net.ListenConfig {
-	return &net.ListenConfig{
-		Control: func(network, address string, c syscall.RawConn) error {
-			for _, fn := range controlFns {
-				if err := fn(network, address, c); err != nil {
-					return err
-				}
-			}
-
-			if q == 0 {
-				c.Control(func(fd uintptr) {
-					EvilFdZero = fd
-				})
-				//	var e error
-				//	err := c.Control(func(fd uintptr) {
-				//		e = reusePortHax(fd)
-				//	})
-				//	if err != nil {
-				//		return err
-				//	}
-				//	if e != nil {
-				//		return e
-				//	}
-			}
-
-			return nil
-		},
-	}
-}

wgstack/conn/controlfns_linux.go

@@ -1,66 +0,0 @@
-//go:build linux
-
-// SPDX-License-Identifier: MIT
-//
-// Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
-
-package conn
-
-import (
-	"fmt"
-	"runtime"
-	"syscall"
-
-	"golang.org/x/sys/unix"
-)
-
-func init() {
-	controlFns = append(controlFns,
-
-		// Attempt to set the socket buffer size beyond net.core.{r,w}mem_max by
-		// using SO_*BUFFORCE. This requires CAP_NET_ADMIN, and is allowed here to
-		// fail silently - the result of failure is lower performance on very fast
-		// links or high latency links.
-		func(network, address string, c syscall.RawConn) error {
-			return c.Control(func(fd uintptr) {
-				// Set up to *mem_max
-				_ = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_RCVBUF, socketBufferSize)
-				_ = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_SNDBUF, socketBufferSize)
-				// Set beyond *mem_max if CAP_NET_ADMIN
-				_ = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_RCVBUFFORCE, socketBufferSize)
-				_ = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_SNDBUFFORCE, socketBufferSize)
-				_ = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_REUSEPORT, 1)  //todo!!!
-				_ = unix.SetsockoptInt(int(fd), unix.IPPROTO_UDP, unix.UDP_GRO, 1)      //todo!!!
-				_ = unix.SetsockoptInt(int(fd), unix.SOL_UDP, unix.UDP_SEGMENT, 0xffff) //todo!!!
-				//print(err.Error())
-			})
-		},
-
-		// Enable receiving of the packet information (IP_PKTINFO for IPv4,
-		// IPV6_PKTINFO for IPv6) that is used to implement sticky socket support.
-		func(network, address string, c syscall.RawConn) error {
-			var err error
-			switch network {
-			case "udp4":
-				if runtime.GOOS != "android" {
-					c.Control(func(fd uintptr) {
-						err = unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_PKTINFO, 1)
-					})
-				}
-			case "udp6":
-				c.Control(func(fd uintptr) {
-					if runtime.GOOS != "android" {
-						err = unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_RECVPKTINFO, 1)
-						if err != nil {
-							return
-						}
-					}
-					err = unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_V6ONLY, 1)
-				})
-			default:
-				err = fmt.Errorf("unhandled network: %s: %w", network, unix.EINVAL)
-			}
-			return err
-		},
-	)
-}

wgstack/conn/default.go

@@ -1,9 +0,0 @@
-//go:build !windows
-
-// SPDX-License-Identifier: MIT
-//
-// Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
-
-package conn
-
-func NewDefaultBind() Bind { return NewStdNetBind() }

wgstack/conn/errors_default.go

@@ -1,12 +0,0 @@
-//go:build !linux
-
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-func errShouldDisableUDPGSO(err error) bool {
-	return false
-}

wgstack/conn/errors_linux.go

@@ -1,26 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-import (
-	"errors"
-	"os"
-
-	"golang.org/x/sys/unix"
-)
-
-func errShouldDisableUDPGSO(err error) bool {
-	var serr *os.SyscallError
-	if errors.As(err, &serr) {
-		// EIO is returned by udp_send_skb() if the device driver does not have
-		// tx checksumming enabled, which is a hard requirement of UDP_SEGMENT.
-		// See:
-		// https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/man7/udp.7?id=806eabd74910447f21005160e90957bde4db0183#n228
-		// https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/udp.c?h=v6.2&id=c9c3395d5e3dcc6daee66c6908354d47bf98cb0c#n942
-		return serr.Err == unix.EIO
-	}
-	return false
-}

wgstack/conn/features_default.go

@@ -1,15 +0,0 @@
-//go:build !linux
-// +build !linux
-
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-import "net"
-
-func supportsUDPOffload(conn *net.UDPConn) (txOffload, rxOffload bool) {
-	return
-}

wgstack/conn/features_linux.go

@@ -1,33 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-import (
-	"fmt"
-	"net"
-
-	"golang.org/x/sys/unix"
-)
-
-func supportsUDPOffload(conn *net.UDPConn) (txOffload, rxOffload bool) {
-	rc, err := conn.SyscallConn()
-	if err != nil {
-		return
-	}
-	a := 0
-	err = rc.Control(func(fd uintptr) {
-		a, err = unix.GetsockoptInt(int(fd), unix.IPPROTO_UDP, unix.UDP_SEGMENT)
-
-		txOffload = err == nil
-		opt, errSyscall := unix.GetsockoptInt(int(fd), unix.IPPROTO_UDP, unix.UDP_GRO)
-		rxOffload = errSyscall == nil && opt == 1
-	})
-	fmt.Printf("%d", a)
-	if err != nil {
-		return false, false
-	}
-	return txOffload, rxOffload
-}

wgstack/conn/gso_default.go

@@ -1,21 +0,0 @@
-//go:build !linux
-
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-// getGSOSize parses control for UDP_GRO and if found returns its GSO size data.
-func getGSOSize(control []byte) (int, error) {
-	return 0, nil
-}
-
-// setGSOSize sets a UDP_SEGMENT in control based on gsoSize.
-func setGSOSize(control *[]byte, gsoSize uint16) {
-}
-
-// gsoControlSize returns the recommended buffer size for pooling sticky and UDP
-// offloading control data.
-const gsoControlSize = 0

wgstack/conn/gso_linux.go

@@ -1,65 +0,0 @@
-//go:build linux
-
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-import (
-	"fmt"
-	"unsafe"
-
-	"golang.org/x/sys/unix"
-)
-
-const (
-	sizeOfGSOData = 2
-)
-
-// getGSOSize parses control for UDP_GRO and if found returns its GSO size data.
-func getGSOSize(control []byte) (int, error) {
-	var (
-		hdr  unix.Cmsghdr
-		data []byte
-		rem  = control
-		err  error
-	)
-
-	for len(rem) > unix.SizeofCmsghdr {
-		hdr, data, rem, err = unix.ParseOneSocketControlMessage(rem)
-		if err != nil {
-			return 0, fmt.Errorf("error parsing socket control message: %w", err)
-		}
-		if hdr.Level == unix.SOL_UDP && hdr.Type == unix.UDP_GRO && len(data) >= sizeOfGSOData {
-			var gso uint16
-			copy(unsafe.Slice((*byte)(unsafe.Pointer(&gso)), sizeOfGSOData), data[:sizeOfGSOData])
-			return int(gso), nil
-		}
-	}
-	return 0, nil
-}
-
-// setGSOSize sets a UDP_SEGMENT in control based on gsoSize. It leaves existing
-// data in control untouched.
-func setGSOSize(control *[]byte, gsoSize uint16) {
-	existingLen := len(*control)
-	avail := cap(*control) - existingLen
-	space := unix.CmsgSpace(sizeOfGSOData)
-	if avail < space {
-		return
-	}
-	*control = (*control)[:cap(*control)]
-	gsoControl := (*control)[existingLen:]
-	hdr := (*unix.Cmsghdr)(unsafe.Pointer(&(gsoControl)[0]))
-	hdr.Level = unix.SOL_UDP
-	hdr.Type = unix.UDP_SEGMENT
-	hdr.SetLen(unix.CmsgLen(sizeOfGSOData))
-	copy((gsoControl)[unix.CmsgLen(0):], unsafe.Slice((*byte)(unsafe.Pointer(&gsoSize)), sizeOfGSOData))
-	*control = (*control)[:existingLen+space]
-}
-
-// gsoControlSize returns the recommended buffer size for pooling UDP
-// offloading control data.
-var gsoControlSize = unix.CmsgSpace(sizeOfGSOData)

wgstack/conn/mark_unix.go

@@ -1,64 +0,0 @@
-//go:build linux || openbsd || freebsd
-
-// SPDX-License-Identifier: MIT
-//
-// Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
-
-package conn
-
-import (
-	"runtime"
-
-	"golang.org/x/sys/unix"
-)
-
-var fwmarkIoctl int
-
-func init() {
-	switch runtime.GOOS {
-	case "linux", "android":
-		fwmarkIoctl = 36 /* unix.SO_MARK */
-	case "freebsd":
-		fwmarkIoctl = 0x1015 /* unix.SO_USER_COOKIE */
-	case "openbsd":
-		fwmarkIoctl = 0x1021 /* unix.SO_RTABLE */
-	}
-}
-
-func (s *StdNetBind) SetMark(mark uint32) error {
-	var operr error
-	if fwmarkIoctl == 0 {
-		return nil
-	}
-	if s.ipv4 != nil {
-		fd, err := s.ipv4.SyscallConn()
-		if err != nil {
-			return err
-		}
-		err = fd.Control(func(fd uintptr) {
-			operr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, fwmarkIoctl, int(mark))
-		})
-		if err == nil {
-			err = operr
-		}
-		if err != nil {
-			return err
-		}
-	}
-	if s.ipv6 != nil {
-		fd, err := s.ipv6.SyscallConn()
-		if err != nil {
-			return err
-		}
-		err = fd.Control(func(fd uintptr) {
-			operr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, fwmarkIoctl, int(mark))
-		})
-		if err == nil {
-			err = operr
-		}
-		if err != nil {
-			return err
-		}
-	}
-	return nil
-}

wgstack/conn/sticky_default.go

@@ -1,42 +0,0 @@
-//go:build !linux || android
-
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-import "net/netip"
-
-func (e *StdNetEndpoint) SrcIP() netip.Addr {
-	return netip.Addr{}
-}
-
-func (e *StdNetEndpoint) SrcIfidx() int32 {
-	return 0
-}
-
-func (e *StdNetEndpoint) SrcToString() string {
-	return ""
-}
-
-// TODO: macOS, FreeBSD and other BSDs likely do support the sticky sockets
-// {get,set}srcControl feature set, but use alternatively named flags and need
-// ports and require testing.
-
-// getSrcFromControl parses the control for PKTINFO and if found updates ep with
-// the source information found.
-func getSrcFromControl(control []byte, ep *StdNetEndpoint) {
-}
-
-// setSrcControl parses the control for PKTINFO and if found updates ep with
-// the source information found.
-func setSrcControl(control *[]byte, ep *StdNetEndpoint) {
-}
-
-// stickyControlSize returns the recommended buffer size for pooling sticky
-// offloading control data.
-const stickyControlSize = 0
-
-const StdNetSupportsStickySockets = false

wgstack/conn/sticky_linux.go

@@ -1,105 +0,0 @@
-package conn
-
-import (
-	"net/netip"
-	"unsafe"
-
-	"golang.org/x/sys/unix"
-)
-
-func (e *StdNetEndpoint) SrcIP() netip.Addr {
-	switch len(e.src) {
-	case unix.CmsgSpace(unix.SizeofInet4Pktinfo):
-		info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&e.src[unix.CmsgLen(0)]))
-		return netip.AddrFrom4(info.Spec_dst)
-	case unix.CmsgSpace(unix.SizeofInet6Pktinfo):
-		info := (*unix.Inet6Pktinfo)(unsafe.Pointer(&e.src[unix.CmsgLen(0)]))
-		// TODO: set zone. in order to do so we need to check if the address is
-		// link local, and if it is perform a syscall to turn the ifindex into a
-		// zone string because netip uses string zones.
-		return netip.AddrFrom16(info.Addr)
-	}
-	return netip.Addr{}
-}
-
-func (e *StdNetEndpoint) SrcIfidx() int32 {
-	switch len(e.src) {
-	case unix.CmsgSpace(unix.SizeofInet4Pktinfo):
-		info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&e.src[unix.CmsgLen(0)]))
-		return info.Ifindex
-	case unix.CmsgSpace(unix.SizeofInet6Pktinfo):
-		info := (*unix.Inet6Pktinfo)(unsafe.Pointer(&e.src[unix.CmsgLen(0)]))
-		return int32(info.Ifindex)
-	}
-	return 0
-}
-
-func (e *StdNetEndpoint) SrcToString() string {
-	return e.SrcIP().String()
-}
-
-// getSrcFromControl parses the control for PKTINFO and if found updates ep with
-// the source information found.
-func getSrcFromControl(control []byte, ep *StdNetEndpoint) {
-	ep.ClearSrc()
-
-	var (
-		hdr  unix.Cmsghdr
-		data []byte
-		rem  []byte = control
-		err  error
-	)
-
-	for len(rem) > unix.SizeofCmsghdr {
-		hdr, data, rem, err = unix.ParseOneSocketControlMessage(rem)
-		if err != nil {
-			return
-		}
-
-		if hdr.Level == unix.IPPROTO_IP &&
-			hdr.Type == unix.IP_PKTINFO {
-
-			if ep.src == nil || cap(ep.src) < unix.CmsgSpace(unix.SizeofInet4Pktinfo) {
-				ep.src = make([]byte, 0, unix.CmsgSpace(unix.SizeofInet4Pktinfo))
-			}
-			ep.src = ep.src[:unix.CmsgSpace(unix.SizeofInet4Pktinfo)]
-
-			hdrBuf := unsafe.Slice((*byte)(unsafe.Pointer(&hdr)), unix.SizeofCmsghdr)
-			copy(ep.src, hdrBuf)
-			copy(ep.src[unix.CmsgLen(0):], data)
-			return
-		}
-
-		if hdr.Level == unix.IPPROTO_IPV6 &&
-			hdr.Type == unix.IPV6_PKTINFO {
-
-			if ep.src == nil || cap(ep.src) < unix.CmsgSpace(unix.SizeofInet6Pktinfo) {
-				ep.src = make([]byte, 0, unix.CmsgSpace(unix.SizeofInet6Pktinfo))
-			}
-
-			ep.src = ep.src[:unix.CmsgSpace(unix.SizeofInet6Pktinfo)]
-
-			hdrBuf := unsafe.Slice((*byte)(unsafe.Pointer(&hdr)), unix.SizeofCmsghdr)
-			copy(ep.src, hdrBuf)
-			copy(ep.src[unix.CmsgLen(0):], data)
-			return
-		}
-	}
-}
-
-// setSrcControl sets an IP{V6}_PKTINFO in control based on the source address
-// and source ifindex found in ep. control's len will be set to 0 in the event
-// that ep is a default value.
-func setSrcControl(control *[]byte, ep *StdNetEndpoint) {
-	if cap(*control) < len(ep.src) {
-		return
-	}
-	*control = (*control)[:0]
-	*control = append(*control, ep.src...)
-}
-
-// stickyControlSize returns the recommended buffer size for pooling sticky
-// offloading control data.
-var stickyControlSize = unix.CmsgSpace(unix.SizeofInet6Pktinfo)
-
-const StdNetSupportsStickySockets = true

wgstack/tun/checksum.go

@@ -1,42 +0,0 @@
-package tun
-
-import "encoding/binary"
-
-// TODO: Explore SIMD and/or other assembly optimizations.
-func checksumNoFold(b []byte, initial uint64) uint64 {
-	ac := initial
-	i := 0
-	n := len(b)
-	for n >= 4 {
-		ac += uint64(binary.BigEndian.Uint32(b[i : i+4]))
-		n -= 4
-		i += 4
-	}
-	for n >= 2 {
-		ac += uint64(binary.BigEndian.Uint16(b[i : i+2]))
-		n -= 2
-		i += 2
-	}
-	if n == 1 {
-		ac += uint64(b[i]) << 8
-	}
-	return ac
-}
-
-func checksum(b []byte, initial uint64) uint16 {
-	ac := checksumNoFold(b, initial)
-	ac = (ac >> 16) + (ac & 0xffff)
-	ac = (ac >> 16) + (ac & 0xffff)
-	ac = (ac >> 16) + (ac & 0xffff)
-	ac = (ac >> 16) + (ac & 0xffff)
-	return uint16(ac)
-}
-
-func pseudoHeaderChecksumNoFold(protocol uint8, srcAddr, dstAddr []byte, totalLen uint16) uint64 {
-	sum := checksumNoFold(srcAddr, 0)
-	sum = checksumNoFold(dstAddr, sum)
-	sum = checksumNoFold([]byte{0, protocol}, sum)
-	tmp := make([]byte, 2)
-	binary.BigEndian.PutUint16(tmp, totalLen)
-	return checksumNoFold(tmp, sum)
-}

wgstack/tun/export.go

@@ -1,3 +0,0 @@
-package tun
-
-const VirtioNetHdrLen = virtioNetHdrLen

wgstack/tun/tcp_offload_linux.go

@@ -1,630 +0,0 @@
-//go:build linux
-
-// SPDX-License-Identifier: MIT
-//
-// Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
-
-package tun
-
-import (
-	"bytes"
-	"encoding/binary"
-	"errors"
-	"io"
-	"unsafe"
-
-	wgconn "github.com/slackhq/nebula/wgstack/conn"
-	"golang.org/x/sys/unix"
-)
-
-var ErrTooManySegments = errors.New("tun: too many segments for TSO")
-
-const tcpFlagsOffset = 13
-
-const (
-	tcpFlagFIN uint8 = 0x01
-	tcpFlagPSH uint8 = 0x08
-	tcpFlagACK uint8 = 0x10
-)
-
-// virtioNetHdr is defined in the kernel in include/uapi/linux/virtio_net.h. The
-// kernel symbol is virtio_net_hdr.
-type virtioNetHdr struct {
-	flags      uint8
-	gsoType    uint8
-	hdrLen     uint16
-	gsoSize    uint16
-	csumStart  uint16
-	csumOffset uint16
-}
-
-func (v *virtioNetHdr) decode(b []byte) error {
-	if len(b) < virtioNetHdrLen {
-		return io.ErrShortBuffer
-	}
-	copy(unsafe.Slice((*byte)(unsafe.Pointer(v)), virtioNetHdrLen), b[:virtioNetHdrLen])
-	return nil
-}
-
-func (v *virtioNetHdr) encode(b []byte) error {
-	if len(b) < virtioNetHdrLen {
-		return io.ErrShortBuffer
-	}
-	copy(b[:virtioNetHdrLen], unsafe.Slice((*byte)(unsafe.Pointer(v)), virtioNetHdrLen))
-	return nil
-}
-
-const (
-	// virtioNetHdrLen is the length in bytes of virtioNetHdr. This matches the
-	// shape of the C ABI for its kernel counterpart -- sizeof(virtio_net_hdr).
-	virtioNetHdrLen = int(unsafe.Sizeof(virtioNetHdr{}))
-)
-
-// flowKey represents the key for a flow.
-type flowKey struct {
-	srcAddr, dstAddr [16]byte
-	srcPort, dstPort uint16
-	rxAck            uint32 // varying ack values should not be coalesced. Treat them as separate flows.
-}
-
-// tcpGROTable holds flow and coalescing information for the purposes of GRO.
-type tcpGROTable struct {
-	itemsByFlow map[flowKey][]tcpGROItem
-	itemsPool   [][]tcpGROItem
-}
-
-func newTCPGROTable() *tcpGROTable {
-	t := &tcpGROTable{
-		itemsByFlow: make(map[flowKey][]tcpGROItem, wgconn.IdealBatchSize),
-		itemsPool:   make([][]tcpGROItem, wgconn.IdealBatchSize),
-	}
-	for i := range t.itemsPool {
-		t.itemsPool[i] = make([]tcpGROItem, 0, wgconn.IdealBatchSize)
-	}
-	return t
-}
-
-func newFlowKey(pkt []byte, srcAddr, dstAddr, tcphOffset int) flowKey {
-	key := flowKey{}
-	addrSize := dstAddr - srcAddr
-	copy(key.srcAddr[:], pkt[srcAddr:dstAddr])
-	copy(key.dstAddr[:], pkt[dstAddr:dstAddr+addrSize])
-	key.srcPort = binary.BigEndian.Uint16(pkt[tcphOffset:])
-	key.dstPort = binary.BigEndian.Uint16(pkt[tcphOffset+2:])
-	key.rxAck = binary.BigEndian.Uint32(pkt[tcphOffset+8:])
-	return key
-}
-
-// lookupOrInsert looks up a flow for the provided packet and metadata,
-// returning the packets found for the flow, or inserting a new one if none
-// is found.
-func (t *tcpGROTable) lookupOrInsert(pkt []byte, srcAddrOffset, dstAddrOffset, tcphOffset, tcphLen, bufsIndex int) ([]tcpGROItem, bool) {
-	key := newFlowKey(pkt, srcAddrOffset, dstAddrOffset, tcphOffset)
-	items, ok := t.itemsByFlow[key]
-	if ok {
-		return items, ok
-	}
-	// TODO: insert() performs another map lookup. This could be rearranged to avoid.
-	t.insert(pkt, srcAddrOffset, dstAddrOffset, tcphOffset, tcphLen, bufsIndex)
-	return nil, false
-}
-
-// insert an item in the table for the provided packet and packet metadata.
-func (t *tcpGROTable) insert(pkt []byte, srcAddrOffset, dstAddrOffset, tcphOffset, tcphLen, bufsIndex int) {
-	key := newFlowKey(pkt, srcAddrOffset, dstAddrOffset, tcphOffset)
-	item := tcpGROItem{
-		key:       key,
-		bufsIndex: uint16(bufsIndex),
-		gsoSize:   uint16(len(pkt[tcphOffset+tcphLen:])),
-		iphLen:    uint8(tcphOffset),
-		tcphLen:   uint8(tcphLen),
-		sentSeq:   binary.BigEndian.Uint32(pkt[tcphOffset+4:]),
-		pshSet:    pkt[tcphOffset+tcpFlagsOffset]&tcpFlagPSH != 0,
-	}
-	items, ok := t.itemsByFlow[key]
-	if !ok {
-		items = t.newItems()
-	}
-	items = append(items, item)
-	t.itemsByFlow[key] = items
-}
-
-func (t *tcpGROTable) updateAt(item tcpGROItem, i int) {
-	items, _ := t.itemsByFlow[item.key]
-	items[i] = item
-}
-
-func (t *tcpGROTable) deleteAt(key flowKey, i int) {
-	items, _ := t.itemsByFlow[key]
-	items = append(items[:i], items[i+1:]...)
-	t.itemsByFlow[key] = items
-}
-
-// tcpGROItem represents bookkeeping data for a TCP packet during the lifetime
-// of a GRO evaluation across a vector of packets.
-type tcpGROItem struct {
-	key       flowKey
-	sentSeq   uint32 // the sequence number
-	bufsIndex uint16 // the index into the original bufs slice
-	numMerged uint16 // the number of packets merged into this item
-	gsoSize   uint16 // payload size
-	iphLen    uint8  // ip header len
-	tcphLen   uint8  // tcp header len
-	pshSet    bool   // psh flag is set
-}
-
-func (t *tcpGROTable) newItems() []tcpGROItem {
-	var items []tcpGROItem
-	items, t.itemsPool = t.itemsPool[len(t.itemsPool)-1], t.itemsPool[:len(t.itemsPool)-1]
-	return items
-}
-
-func (t *tcpGROTable) reset() {
-	for k, items := range t.itemsByFlow {
-		items = items[:0]
-		t.itemsPool = append(t.itemsPool, items)
-		delete(t.itemsByFlow, k)
-	}
-}
-
-// canCoalesce represents the outcome of checking if two TCP packets are
-// candidates for coalescing.
-type canCoalesce int
-
-const (
-	coalescePrepend     canCoalesce = -1
-	coalesceUnavailable canCoalesce = 0
-	coalesceAppend      canCoalesce = 1
-)
-
-// tcpPacketsCanCoalesce evaluates if pkt can be coalesced with the packet
-// described by item. This function makes considerations that match the kernel's
-// GRO self tests, which can be found in tools/testing/selftests/net/gro.c.
-func tcpPacketsCanCoalesce(pkt []byte, iphLen, tcphLen uint8, seq uint32, pshSet bool, gsoSize uint16, item tcpGROItem, bufs [][]byte, bufsOffset int) canCoalesce {
-	pktTarget := bufs[item.bufsIndex][bufsOffset:]
-	if tcphLen != item.tcphLen {
-		// cannot coalesce with unequal tcp options len
-		return coalesceUnavailable
-	}
-	if tcphLen > 20 {
-		if !bytes.Equal(pkt[iphLen+20:iphLen+tcphLen], pktTarget[item.iphLen+20:iphLen+tcphLen]) {
-			// cannot coalesce with unequal tcp options
-			return coalesceUnavailable
-		}
-	}
-	if pkt[0]>>4 == 6 {
-		if pkt[0] != pktTarget[0] || pkt[1]>>4 != pktTarget[1]>>4 {
-			// cannot coalesce with unequal Traffic class values
-			return coalesceUnavailable
-		}
-		if pkt[7] != pktTarget[7] {
-			// cannot coalesce with unequal Hop limit values
-			return coalesceUnavailable
-		}
-	} else {
-		if pkt[1] != pktTarget[1] {
-			// cannot coalesce with unequal ToS values
-			return coalesceUnavailable
-		}
-		if pkt[6]>>5 != pktTarget[6]>>5 {
-			// cannot coalesce with unequal DF or reserved bits. MF is checked
-			// further up the stack.
-			return coalesceUnavailable
-		}
-		if pkt[8] != pktTarget[8] {
-			// cannot coalesce with unequal TTL values
-			return coalesceUnavailable
-		}
-	}
-	// seq adjacency
-	lhsLen := item.gsoSize
-	lhsLen += item.numMerged * item.gsoSize
-	if seq == item.sentSeq+uint32(lhsLen) { // pkt aligns following item from a seq num perspective
-		if item.pshSet {
-			// We cannot append to a segment that has the PSH flag set, PSH
-			// can only be set on the final segment in a reassembled group.
-			return coalesceUnavailable
-		}
-		if len(pktTarget[iphLen+tcphLen:])%int(item.gsoSize) != 0 {
-			// A smaller than gsoSize packet has been appended previously.
-			// Nothing can come after a smaller packet on the end.
-			return coalesceUnavailable
-		}
-		if gsoSize > item.gsoSize {
-			// We cannot have a larger packet following a smaller one.
-			return coalesceUnavailable
-		}
-		return coalesceAppend
-	} else if seq+uint32(gsoSize) == item.sentSeq { // pkt aligns in front of item from a seq num perspective
-		if pshSet {
-			// We cannot prepend with a segment that has the PSH flag set, PSH
-			// can only be set on the final segment in a reassembled group.
-			return coalesceUnavailable
-		}
-		if gsoSize < item.gsoSize {
-			// We cannot have a larger packet following a smaller one.
-			return coalesceUnavailable
-		}
-		if gsoSize > item.gsoSize && item.numMerged > 0 {
-			// There's at least one previous merge, and we're larger than all
-			// previous. This would put multiple smaller packets on the end.
-			return coalesceUnavailable
-		}
-		return coalescePrepend
-	}
-	return coalesceUnavailable
-}
-
-func tcpChecksumValid(pkt []byte, iphLen uint8, isV6 bool) bool {
-	srcAddrAt := ipv4SrcAddrOffset
-	addrSize := 4
-	if isV6 {
-		srcAddrAt = ipv6SrcAddrOffset
-		addrSize = 16
-	}
-	tcpTotalLen := uint16(len(pkt) - int(iphLen))
-	tcpCSumNoFold := pseudoHeaderChecksumNoFold(unix.IPPROTO_TCP, pkt[srcAddrAt:srcAddrAt+addrSize], pkt[srcAddrAt+addrSize:srcAddrAt+addrSize*2], tcpTotalLen)
-	return ^checksum(pkt[iphLen:], tcpCSumNoFold) == 0
-}
-
-// coalesceResult represents the result of attempting to coalesce two TCP
-// packets.
-type coalesceResult int
-
-const (
-	coalesceInsufficientCap coalesceResult = 0
-	coalescePSHEnding       coalesceResult = 1
-	coalesceItemInvalidCSum coalesceResult = 2
-	coalescePktInvalidCSum  coalesceResult = 3
-	coalesceSuccess         coalesceResult = 4
-)
-
-// coalesceTCPPackets attempts to coalesce pkt with the packet described by
-// item, returning the outcome. This function may swap bufs elements in the
-// event of a prepend as item's bufs index is already being tracked for writing
-// to a Device.
-func coalesceTCPPackets(mode canCoalesce, pkt []byte, pktBuffsIndex int, gsoSize uint16, seq uint32, pshSet bool, item *tcpGROItem, bufs [][]byte, bufsOffset int, isV6 bool) coalesceResult {
-	var pktHead []byte // the packet that will end up at the front
-	headersLen := item.iphLen + item.tcphLen
-	coalescedLen := len(bufs[item.bufsIndex][bufsOffset:]) + len(pkt) - int(headersLen)
-
-	// Copy data
-	if mode == coalescePrepend {
-		pktHead = pkt
-		if cap(pkt)-bufsOffset < coalescedLen {
-			// We don't want to allocate a new underlying array if capacity is
-			// too small.
-			return coalesceInsufficientCap
-		}
-		if pshSet {
-			return coalescePSHEnding
-		}
-		if item.numMerged == 0 {
-			if !tcpChecksumValid(bufs[item.bufsIndex][bufsOffset:], item.iphLen, isV6) {
-				return coalesceItemInvalidCSum
-			}
-		}
-		if !tcpChecksumValid(pkt, item.iphLen, isV6) {
-			return coalescePktInvalidCSum
-		}
-		item.sentSeq = seq
-		extendBy := coalescedLen - len(pktHead)
-		bufs[pktBuffsIndex] = append(bufs[pktBuffsIndex], make([]byte, extendBy)...)
-		copy(bufs[pktBuffsIndex][bufsOffset+len(pkt):], bufs[item.bufsIndex][bufsOffset+int(headersLen):])
-		// Flip the slice headers in bufs as part of prepend. The index of item
-		// is already being tracked for writing.
-		bufs[item.bufsIndex], bufs[pktBuffsIndex] = bufs[pktBuffsIndex], bufs[item.bufsIndex]
-	} else {
-		pktHead = bufs[item.bufsIndex][bufsOffset:]
-		if cap(pktHead)-bufsOffset < coalescedLen {
-			// We don't want to allocate a new underlying array if capacity is
-			// too small.
-			return coalesceInsufficientCap
-		}
-		if item.numMerged == 0 {
-			if !tcpChecksumValid(bufs[item.bufsIndex][bufsOffset:], item.iphLen, isV6) {
-				return coalesceItemInvalidCSum
-			}
-		}
-		if !tcpChecksumValid(pkt, item.iphLen, isV6) {
-			return coalescePktInvalidCSum
-		}
-		if pshSet {
-			// We are appending a segment with PSH set.
-			item.pshSet = pshSet
-			pktHead[item.iphLen+tcpFlagsOffset] |= tcpFlagPSH
-		}
-		extendBy := len(pkt) - int(headersLen)
-		bufs[item.bufsIndex] = append(bufs[item.bufsIndex], make([]byte, extendBy)...)
-		copy(bufs[item.bufsIndex][bufsOffset+len(pktHead):], pkt[headersLen:])
-	}
-
-	if gsoSize > item.gsoSize {
-		item.gsoSize = gsoSize
-	}
-	hdr := virtioNetHdr{
-		flags:      unix.VIRTIO_NET_HDR_F_NEEDS_CSUM, // this turns into CHECKSUM_PARTIAL in the skb
-		hdrLen:     uint16(headersLen),
-		gsoSize:    uint16(item.gsoSize),
-		csumStart:  uint16(item.iphLen),
-		csumOffset: 16,
-	}
-
-	// Recalculate the total len (IPv4) or payload len (IPv6). Recalculate the
-	// (IPv4) header checksum.
-	if isV6 {
-		hdr.gsoType = unix.VIRTIO_NET_HDR_GSO_TCPV6
-		binary.BigEndian.PutUint16(pktHead[4:], uint16(coalescedLen)-uint16(item.iphLen)) // set new payload len
-	} else {
-		hdr.gsoType = unix.VIRTIO_NET_HDR_GSO_TCPV4
-		pktHead[10], pktHead[11] = 0, 0                               // clear checksum field
-		binary.BigEndian.PutUint16(pktHead[2:], uint16(coalescedLen)) // set new total length
-		iphCSum := ^checksum(pktHead[:item.iphLen], 0)                // compute checksum
-		binary.BigEndian.PutUint16(pktHead[10:], iphCSum)             // set checksum field
-	}
-	hdr.encode(bufs[item.bufsIndex][bufsOffset-virtioNetHdrLen:])
-
-	// Calculate the pseudo header checksum and place it at the TCP checksum
-	// offset. Downstream checksum offloading will combine this with computation
-	// of the tcp header and payload checksum.
-	addrLen := 4
-	addrOffset := ipv4SrcAddrOffset
-	if isV6 {
-		addrLen = 16
-		addrOffset = ipv6SrcAddrOffset
-	}
-	srcAddrAt := bufsOffset + addrOffset
-	srcAddr := bufs[item.bufsIndex][srcAddrAt : srcAddrAt+addrLen]
-	dstAddr := bufs[item.bufsIndex][srcAddrAt+addrLen : srcAddrAt+addrLen*2]
-	psum := pseudoHeaderChecksumNoFold(unix.IPPROTO_TCP, srcAddr, dstAddr, uint16(coalescedLen-int(item.iphLen)))
-	binary.BigEndian.PutUint16(pktHead[hdr.csumStart+hdr.csumOffset:], checksum([]byte{}, psum))
-
-	item.numMerged++
-	return coalesceSuccess
-}
-
-const (
-	ipv4FlagMoreFragments uint8 = 0x20
-)
-
-const (
-	ipv4SrcAddrOffset = 12
-	ipv6SrcAddrOffset = 8
-	maxUint16         = 1<<16 - 1
-)
-
-// tcpGRO evaluates the TCP packet at pktI in bufs for coalescing with
-// existing packets tracked in table. It will return false when pktI is not
-// coalesced, otherwise true. This indicates to the caller if bufs[pktI]
-// should be written to the Device.
-func tcpGRO(bufs [][]byte, offset int, pktI int, table *tcpGROTable, isV6 bool) (pktCoalesced bool) {
-	pkt := bufs[pktI][offset:]
-	if len(pkt) > maxUint16 {
-		// A valid IPv4 or IPv6 packet will never exceed this.
-		return false
-	}
-	iphLen := int((pkt[0] & 0x0F) * 4)
-	if isV6 {
-		iphLen = 40
-		ipv6HPayloadLen := int(binary.BigEndian.Uint16(pkt[4:]))
-		if ipv6HPayloadLen != len(pkt)-iphLen {
-			return false
-		}
-	} else {
-		totalLen := int(binary.BigEndian.Uint16(pkt[2:]))
-		if totalLen != len(pkt) {
-			return false
-		}
-	}
-	if len(pkt) < iphLen {
-		return false
-	}
-	tcphLen := int((pkt[iphLen+12] >> 4) * 4)
-	if tcphLen < 20 || tcphLen > 60 {
-		return false
-	}
-	if len(pkt) < iphLen+tcphLen {
-		return false
-	}
-	if !isV6 {
-		if pkt[6]&ipv4FlagMoreFragments != 0 || pkt[6]<<3 != 0 || pkt[7] != 0 {
-			// no GRO support for fragmented segments for now
-			return false
-		}
-	}
-	tcpFlags := pkt[iphLen+tcpFlagsOffset]
-	var pshSet bool
-	// not a candidate if any non-ACK flags (except PSH+ACK) are set
-	if tcpFlags != tcpFlagACK {
-		if pkt[iphLen+tcpFlagsOffset] != tcpFlagACK|tcpFlagPSH {
-			return false
-		}
-		pshSet = true
-	}
-	gsoSize := uint16(len(pkt) - tcphLen - iphLen)
-	// not a candidate if payload len is 0
-	if gsoSize < 1 {
-		return false
-	}
-	seq := binary.BigEndian.Uint32(pkt[iphLen+4:])
-	srcAddrOffset := ipv4SrcAddrOffset
-	addrLen := 4
-	if isV6 {
-		srcAddrOffset = ipv6SrcAddrOffset
-		addrLen = 16
-	}
-	items, existing := table.lookupOrInsert(pkt, srcAddrOffset, srcAddrOffset+addrLen, iphLen, tcphLen, pktI)
-	if !existing {
-		return false
-	}
-	for i := len(items) - 1; i >= 0; i-- {
-		// In the best case of packets arriving in order iterating in reverse is
-		// more efficient if there are multiple items for a given flow. This
-		// also enables a natural table.deleteAt() in the
-		// coalesceItemInvalidCSum case without the need for index tracking.
-		// This algorithm makes a best effort to coalesce in the event of
-		// unordered packets, where pkt may land anywhere in items from a
-		// sequence number perspective, however once an item is inserted into
-		// the table it is never compared across other items later.
-		item := items[i]
-		can := tcpPacketsCanCoalesce(pkt, uint8(iphLen), uint8(tcphLen), seq, pshSet, gsoSize, item, bufs, offset)
-		if can != coalesceUnavailable {
-			result := coalesceTCPPackets(can, pkt, pktI, gsoSize, seq, pshSet, &item, bufs, offset, isV6)
-			switch result {
-			case coalesceSuccess:
-				table.updateAt(item, i)
-				return true
-			case coalesceItemInvalidCSum:
-				// delete the item with an invalid csum
-				table.deleteAt(item.key, i)
-			case coalescePktInvalidCSum:
-				// no point in inserting an item that we can't coalesce
-				return false
-			default:
-			}
-		}
-	}
-	// failed to coalesce with any other packets; store the item in the flow
-	table.insert(pkt, srcAddrOffset, srcAddrOffset+addrLen, iphLen, tcphLen, pktI)
-	return false
-}
-
-func isTCP4NoIPOptions(b []byte) bool {
-	if len(b) < 40 {
-		return false
-	}
-	if b[0]>>4 != 4 {
-		return false
-	}
-	if b[0]&0x0F != 5 {
-		return false
-	}
-	if b[9] != unix.IPPROTO_TCP {
-		return false
-	}
-	return true
-}
-
-func isTCP6NoEH(b []byte) bool {
-	if len(b) < 60 {
-		return false
-	}
-	if b[0]>>4 != 6 {
-		return false
-	}
-	if b[6] != unix.IPPROTO_TCP {
-		return false
-	}
-	return true
-}
-
-// handleGRO evaluates bufs for GRO, and writes the indices of the resulting
-// packets into toWrite. toWrite, tcp4Table, and tcp6Table should initially be
-// empty (but non-nil), and are passed in to save allocs as the caller may reset
-// and recycle them across vectors of packets.
-func handleGRO(bufs [][]byte, offset int, tcp4Table, tcp6Table *tcpGROTable, toWrite *[]int) error {
-	for i := range bufs {
-		if offset < virtioNetHdrLen || offset > len(bufs[i])-1 {
-			return errors.New("invalid offset")
-		}
-		var coalesced bool
-		switch {
-		case isTCP4NoIPOptions(bufs[i][offset:]): // ipv4 packets w/IP options do not coalesce
-			coalesced = tcpGRO(bufs, offset, i, tcp4Table, false)
-		case isTCP6NoEH(bufs[i][offset:]): // ipv6 packets w/extension headers do not coalesce
-			coalesced = tcpGRO(bufs, offset, i, tcp6Table, true)
-		}
-		if !coalesced {
-			hdr := virtioNetHdr{}
-			err := hdr.encode(bufs[i][offset-virtioNetHdrLen:])
-			if err != nil {
-				return err
-			}
-			*toWrite = append(*toWrite, i)
-		}
-	}
-	return nil
-}
-
-// tcpTSO splits packets from in into outBuffs, writing the size of each
-// element into sizes. It returns the number of buffers populated, and/or an
-// error.
-func tcpTSO(in []byte, hdr virtioNetHdr, outBuffs [][]byte, sizes []int, outOffset int) (int, error) {
-	iphLen := int(hdr.csumStart)
-	srcAddrOffset := ipv6SrcAddrOffset
-	addrLen := 16
-	if hdr.gsoType == unix.VIRTIO_NET_HDR_GSO_TCPV4 {
-		in[10], in[11] = 0, 0 // clear ipv4 header checksum
-		srcAddrOffset = ipv4SrcAddrOffset
-		addrLen = 4
-	}
-	tcpCSumAt := int(hdr.csumStart + hdr.csumOffset)
-	in[tcpCSumAt], in[tcpCSumAt+1] = 0, 0 // clear tcp checksum
-	firstTCPSeqNum := binary.BigEndian.Uint32(in[hdr.csumStart+4:])
-	nextSegmentDataAt := int(hdr.hdrLen)
-	i := 0
-	for ; nextSegmentDataAt < len(in); i++ {
-		if i == len(outBuffs) {
-			return i - 1, ErrTooManySegments
-		}
-		nextSegmentEnd := nextSegmentDataAt + int(hdr.gsoSize)
-		if nextSegmentEnd > len(in) {
-			nextSegmentEnd = len(in)
-		}
-		segmentDataLen := nextSegmentEnd - nextSegmentDataAt
-		totalLen := int(hdr.hdrLen) + segmentDataLen
-		sizes[i] = totalLen
-		out := outBuffs[i][outOffset:]
-
-		copy(out, in[:iphLen])
-		if hdr.gsoType == unix.VIRTIO_NET_HDR_GSO_TCPV4 {
-			// For IPv4 we are responsible for incrementing the ID field,
-			// updating the total len field, and recalculating the header
-			// checksum.
-			if i > 0 {
-				id := binary.BigEndian.Uint16(out[4:])
-				id += uint16(i)
-				binary.BigEndian.PutUint16(out[4:], id)
-			}
-			binary.BigEndian.PutUint16(out[2:], uint16(totalLen))
-			ipv4CSum := ^checksum(out[:iphLen], 0)
-			binary.BigEndian.PutUint16(out[10:], ipv4CSum)
-		} else {
-			// For IPv6 we are responsible for updating the payload length field.
-			binary.BigEndian.PutUint16(out[4:], uint16(totalLen-iphLen))
-		}
-
-		// TCP header
-		copy(out[hdr.csumStart:hdr.hdrLen], in[hdr.csumStart:hdr.hdrLen])
-		tcpSeq := firstTCPSeqNum + uint32(hdr.gsoSize*uint16(i))
-		binary.BigEndian.PutUint32(out[hdr.csumStart+4:], tcpSeq)
-		if nextSegmentEnd != len(in) {
-			// FIN and PSH should only be set on last segment
-			clearFlags := tcpFlagFIN | tcpFlagPSH
-			out[hdr.csumStart+tcpFlagsOffset] &^= clearFlags
-		}
-
-		// payload
-		copy(out[hdr.hdrLen:], in[nextSegmentDataAt:nextSegmentEnd])
-
-		// TCP checksum
-		tcpHLen := int(hdr.hdrLen - hdr.csumStart)
-		tcpLenForPseudo := uint16(tcpHLen + segmentDataLen)
-		tcpCSumNoFold := pseudoHeaderChecksumNoFold(unix.IPPROTO_TCP, in[srcAddrOffset:srcAddrOffset+addrLen], in[srcAddrOffset+addrLen:srcAddrOffset+addrLen*2], tcpLenForPseudo)
-		tcpCSum := ^checksum(out[hdr.csumStart:totalLen], tcpCSumNoFold)
-		binary.BigEndian.PutUint16(out[hdr.csumStart+hdr.csumOffset:], tcpCSum)
-
-		nextSegmentDataAt += int(hdr.gsoSize)
-	}
-	return i, nil
-}
-
-func gsoNoneChecksum(in []byte, cSumStart, cSumOffset uint16) error {
-	cSumAt := cSumStart + cSumOffset
-	// The initial value at the checksum offset should be summed with the
-	// checksum we compute. This is typically the pseudo-header checksum.
-	initial := binary.BigEndian.Uint16(in[cSumAt:])
-	in[cSumAt], in[cSumAt+1] = 0, 0
-	binary.BigEndian.PutUint16(in[cSumAt:], ^checksum(in[cSumStart:], uint64(initial)))
-	return nil
-}

wgstack/tun/tun.go

@@ -1,52 +0,0 @@
-// SPDX-License-Identifier: MIT
-//
-// Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
-
-package tun
-
-import (
-	"os"
-)
-
-type Event int
-
-const (
-	EventUp = 1 << iota
-	EventDown
-	EventMTUUpdate
-)
-
-type Device interface {
-	// File returns the file descriptor of the device.
-	File() *os.File
-
-	// Read one or more packets from the Device (without any additional headers).
-	// On a successful read it returns the number of packets read, and sets
-	// packet lengths within the sizes slice. len(sizes) must be >= len(bufs).
-	// A nonzero offset can be used to instruct the Device on where to begin
-	// reading into each element of the bufs slice.
-	Read(bufs [][]byte, sizes []int, offset int) (n int, err error)
-
-	// Write one or more packets to the device (without any additional headers).
-	// On a successful write it returns the number of packets written. A nonzero
-	// offset can be used to instruct the Device on where to begin writing from
-	// each packet contained within the bufs slice.
-	Write(bufs [][]byte, offset int) (int, error)
-
-	// MTU returns the MTU of the Device.
-	MTU() (int, error)
-
-	// Name returns the current name of the Device.
-	Name() (string, error)
-
-	// Events returns a channel of type Event, which is fed Device events.
-	Events() <-chan Event
-
-	// Close stops the Device and closes the Event channel.
-	Close() error
-
-	// BatchSize returns the preferred/max number of packets that can be read or
-	// written in a single read/write call. BatchSize must not change over the
-	// lifetime of a Device.
-	BatchSize() int
-}

wgstack/tun/tun_linux.go

@@ -1,664 +0,0 @@
-//go:build linux
-
-// SPDX-License-Identifier: MIT
-//
-// Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
-
-package tun
-
-/* Implementation of the TUN device interface for linux
- */
-
-import (
-	"errors"
-	"fmt"
-	"os"
-	"sync"
-	"syscall"
-	"time"
-	"unsafe"
-
-	wgconn "github.com/slackhq/nebula/wgstack/conn"
-	"golang.org/x/sys/unix"
-	"golang.zx2c4.com/wireguard/rwcancel"
-)
-
-const (
-	cloneDevicePath = "/dev/net/tun"
-	ifReqSize       = unix.IFNAMSIZ + 64
-)
-
-type NativeTun struct {
-	tunFile                 *os.File
-	index                   int32      // if index
-	errors                  chan error // async error handling
-	events                  chan Event // device related events
-	netlinkSock             int
-	netlinkCancel           *rwcancel.RWCancel
-	hackListenerClosed      sync.Mutex
-	statusListenersShutdown chan struct{}
-	batchSize               int
-	vnetHdr                 bool
-
-	closeOnce sync.Once
-
-	nameOnce  sync.Once // guards calling initNameCache, which sets following fields
-	nameCache string    // name of interface
-	nameErr   error
-
-	readOpMu sync.Mutex                    // readOpMu guards readBuff
-	readBuff [virtioNetHdrLen + 65535]byte // if vnetHdr every read() is prefixed by virtioNetHdr
-
-	writeOpMu                  sync.Mutex // writeOpMu guards toWrite, tcp4GROTable, tcp6GROTable
-	toWrite                    []int
-	tcp4GROTable, tcp6GROTable *tcpGROTable
-}
-
-func (tun *NativeTun) File() *os.File {
-	return tun.tunFile
-}
-
-func (tun *NativeTun) routineHackListener() {
-	defer tun.hackListenerClosed.Unlock()
-	/* This is needed for the detection to work across network namespaces
-	 * If you are reading this and know a better method, please get in touch.
-	 */
-	last := 0
-	const (
-		up   = 1
-		down = 2
-	)
-	for {
-		sysconn, err := tun.tunFile.SyscallConn()
-		if err != nil {
-			return
-		}
-		err2 := sysconn.Control(func(fd uintptr) {
-			_, err = unix.Write(int(fd), nil)
-		})
-		if err2 != nil {
-			return
-		}
-		switch err {
-		case unix.EINVAL:
-			if last != up {
-				// If the tunnel is up, it reports that write() is
-				// allowed but we provided invalid data.
-				tun.events <- EventUp
-				last = up
-			}
-		case unix.EIO:
-			if last != down {
-				// If the tunnel is down, it reports that no I/O
-				// is possible, without checking our provided data.
-				tun.events <- EventDown
-				last = down
-			}
-		default:
-			return
-		}
-		select {
-		case <-time.After(time.Second):
-			// nothing
-		case <-tun.statusListenersShutdown:
-			return
-		}
-	}
-}
-
-func createNetlinkSocket() (int, error) {
-	sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW|unix.SOCK_CLOEXEC, unix.NETLINK_ROUTE)
-	if err != nil {
-		return -1, err
-	}
-	saddr := &unix.SockaddrNetlink{
-		Family: unix.AF_NETLINK,
-		Groups: unix.RTMGRP_LINK | unix.RTMGRP_IPV4_IFADDR | unix.RTMGRP_IPV6_IFADDR,
-	}
-	err = unix.Bind(sock, saddr)
-	if err != nil {
-		return -1, err
-	}
-	return sock, nil
-}
-
-func (tun *NativeTun) routineNetlinkListener() {
-	defer func() {
-		unix.Close(tun.netlinkSock)
-		tun.hackListenerClosed.Lock()
-		close(tun.events)
-		tun.netlinkCancel.Close()
-	}()
-
-	for msg := make([]byte, 1<<16); ; {
-		var err error
-		var msgn int
-		for {
-			msgn, _, _, _, err = unix.Recvmsg(tun.netlinkSock, msg[:], nil, 0)
-			if err == nil || !rwcancel.RetryAfterError(err) {
-				break
-			}
-			if !tun.netlinkCancel.ReadyRead() {
-				tun.errors <- fmt.Errorf("netlink socket closed: %w", err)
-				return
-			}
-		}
-		if err != nil {
-			tun.errors <- fmt.Errorf("failed to receive netlink message: %w", err)
-			return
-		}
-
-		select {
-		case <-tun.statusListenersShutdown:
-			return
-		default:
-		}
-
-		wasEverUp := false
-		for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
-
-			hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
-
-			if int(hdr.Len) > len(remain) {
-				break
-			}
-
-			switch hdr.Type {
-			case unix.NLMSG_DONE:
-				remain = []byte{}
-
-			case unix.RTM_NEWLINK:
-				info := *(*unix.IfInfomsg)(unsafe.Pointer(&remain[unix.SizeofNlMsghdr]))
-				remain = remain[hdr.Len:]
-
-				if info.Index != tun.index {
-					// not our interface
-					continue
-				}
-
-				if info.Flags&unix.IFF_RUNNING != 0 {
-					tun.events <- EventUp
-					wasEverUp = true
-				}
-
-				if info.Flags&unix.IFF_RUNNING == 0 {
-					// Don't emit EventDown before we've ever emitted EventUp.
-					// This avoids a startup race with HackListener, which
-					// might detect Up before we have finished reporting Down.
-					if wasEverUp {
-						tun.events <- EventDown
-					}
-				}
-
-				tun.events <- EventMTUUpdate
-
-			default:
-				remain = remain[hdr.Len:]
-			}
-		}
-	}
-}
-
-func getIFIndex(name string) (int32, error) {
-	fd, err := unix.Socket(
-		unix.AF_INET,
-		unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
-		0,
-	)
-	if err != nil {
-		return 0, err
-	}
-
-	defer unix.Close(fd)
-
-	var ifr [ifReqSize]byte
-	copy(ifr[:], name)
-	_, _, errno := unix.Syscall(
-		unix.SYS_IOCTL,
-		uintptr(fd),
-		uintptr(unix.SIOCGIFINDEX),
-		uintptr(unsafe.Pointer(&ifr[0])),
-	)
-
-	if errno != 0 {
-		return 0, errno
-	}
-
-	return *(*int32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])), nil
-}
-
-func (tun *NativeTun) setMTU(n int) error {
-	name, err := tun.Name()
-	if err != nil {
-		return err
-	}
-
-	// open datagram socket
-	fd, err := unix.Socket(
-		unix.AF_INET,
-		unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
-		0,
-	)
-	if err != nil {
-		return err
-	}
-	defer unix.Close(fd)
-
-	var ifr [ifReqSize]byte
-	copy(ifr[:], name)
-	*(*uint32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = uint32(n)
-
-	_, _, errno := unix.Syscall(
-		unix.SYS_IOCTL,
-		uintptr(fd),
-		uintptr(unix.SIOCSIFMTU),
-		uintptr(unsafe.Pointer(&ifr[0])),
-	)
-
-	if errno != 0 {
-		return errno
-	}
-	return nil
-}
-
-func (tun *NativeTun) routineNetlinkRead() {
-	defer func() {
-		unix.Close(tun.netlinkSock)
-		tun.hackListenerClosed.Lock()
-		close(tun.events)
-		tun.netlinkCancel.Close()
-	}()
-
-	for msg := make([]byte, 1<<16); ; {
-		var err error
-		var msgn int
-		for {
-			msgn, _, _, _, err = unix.Recvmsg(tun.netlinkSock, msg[:], nil, 0)
-			if err == nil || !rwcancel.RetryAfterError(err) {
-				break
-			}
-			if !tun.netlinkCancel.ReadyRead() {
-				tun.errors <- fmt.Errorf("netlink socket closed: %w", err)
-				return
-			}
-		}
-		if err != nil {
-			tun.errors <- fmt.Errorf("failed to receive netlink message: %w", err)
-			return
-		}
-
-		wasEverUp := false
-		for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
-
-			hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
-
-			if int(hdr.Len) > len(remain) {
-				break
-			}
-
-			switch hdr.Type {
-			case unix.NLMSG_DONE:
-				remain = []byte{}
-
-			case unix.RTM_NEWLINK:
-				info := *(*unix.IfInfomsg)(unsafe.Pointer(&remain[unix.SizeofNlMsghdr]))
-				remain = remain[hdr.Len:]
-
-				if info.Index != tun.index {
-					continue
-				}
-
-				if info.Flags&unix.IFF_RUNNING != 0 {
-					tun.events <- EventUp
-					wasEverUp = true
-				}
-
-				if info.Flags&unix.IFF_RUNNING == 0 {
-					if wasEverUp {
-						tun.events <- EventDown
-					}
-				}
-				tun.events <- EventMTUUpdate
-
-			default:
-				remain = remain[hdr.Len:]
-			}
-		}
-	}
-}
-
-func (tun *NativeTun) routineNetlink() {
-	var err error
-
-	tun.netlinkSock, err = createNetlinkSocket()
-	if err != nil {
-		tun.errors <- fmt.Errorf("failed to create netlink socket: %w", err)
-		return
-	}
-
-	tun.netlinkCancel, err = rwcancel.NewRWCancel(tun.netlinkSock)
-	if err != nil {
-		tun.errors <- fmt.Errorf("failed to create netlink cancel: %w", err)
-		return
-	}
-
-	go tun.routineNetlinkListener()
-}
-
-func (tun *NativeTun) Close() error {
-	var err1, err2 error
-	tun.closeOnce.Do(func() {
-		if tun.statusListenersShutdown != nil {
-			close(tun.statusListenersShutdown)
-			if tun.netlinkCancel != nil {
-				err1 = tun.netlinkCancel.Cancel()
-			}
-		} else if tun.events != nil {
-			close(tun.events)
-		}
-		err2 = tun.tunFile.Close()
-	})
-	if err1 != nil {
-		return err1
-	}
-	return err2
-}
-
-func (tun *NativeTun) BatchSize() int {
-	return tun.batchSize
-}
-
-const (
-	// TODO: support TSO with ECN bits
-	tunOffloads = unix.TUN_F_CSUM | unix.TUN_F_TSO4 | unix.TUN_F_TSO6
-)
-
-func (tun *NativeTun) initFromFlags(name string) error {
-	sc, err := tun.tunFile.SyscallConn()
-	if err != nil {
-		return err
-	}
-	if e := sc.Control(func(fd uintptr) {
-		var (
-			ifr *unix.Ifreq
-		)
-		ifr, err = unix.NewIfreq(name)
-		if err != nil {
-			return
-		}
-		err = unix.IoctlIfreq(int(fd), unix.TUNGETIFF, ifr)
-		if err != nil {
-			return
-		}
-		got := ifr.Uint16()
-		if got&unix.IFF_VNET_HDR != 0 {
-			err = unix.IoctlSetInt(int(fd), unix.TUNSETOFFLOAD, tunOffloads)
-			if err != nil {
-				return
-			}
-			tun.vnetHdr = true
-			tun.batchSize = wgconn.IdealBatchSize
-		} else {
-			tun.batchSize = 1
-		}
-	}); e != nil {
-		return e
-	}
-	return err
-}
-
-// CreateTUN creates a Device with the provided name and MTU.
-func CreateTUN(name string, mtu int) (Device, error) {
-	nfd, err := unix.Open(cloneDevicePath, unix.O_RDWR|unix.O_CLOEXEC, 0)
-	if err != nil {
-		return nil, fmt.Errorf("CreateTUN(%q) failed; %s does not exist", name, cloneDevicePath)
-	}
-	fd := os.NewFile(uintptr(nfd), cloneDevicePath)
-	tun, err := CreateTUNFromFile(fd, mtu)
-	if err != nil {
-		return nil, err
-	}
-	if name != "tun" {
-		if err := tun.(*NativeTun).initFromFlags(name); err != nil {
-			tun.Close()
-			return nil, fmt.Errorf("CreateTUN(%q) failed to set flags: %w", name, err)
-		}
-	}
-	return tun, nil
-}
-
-// CreateTUNFromFile creates a Device from an os.File with the provided MTU.
-func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
-	tun := &NativeTun{
-		tunFile: file,
-		errors:  make(chan error, 5),
-		events:  make(chan Event, 5),
-	}
-
-	name, err := tun.Name()
-	if err != nil {
-		return nil, fmt.Errorf("failed to determine TUN name: %w", err)
-	}
-
-	if err := tun.initFromFlags(name); err != nil {
-		return nil, fmt.Errorf("failed to query TUN flags: %w", err)
-	}
-
-	if tun.batchSize == 0 {
-		tun.batchSize = 1
-	}
-
-	tun.index, err = getIFIndex(name)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get TUN index: %w", err)
-	}
-
-	if err = tun.setMTU(mtu); err != nil {
-		return nil, fmt.Errorf("failed to set MTU: %w", err)
-	}
-
-	tun.statusListenersShutdown = make(chan struct{})
-	go tun.routineNetlink()
-
-	if tun.batchSize == 0 {
-		tun.batchSize = 1
-	}
-
-	tun.tcp4GROTable = newTCPGROTable()
-	tun.tcp6GROTable = newTCPGROTable()
-
-	return tun, nil
-}
-
-func (tun *NativeTun) Name() (string, error) {
-	tun.nameOnce.Do(tun.initNameCache)
-	return tun.nameCache, tun.nameErr
-}
-
-func (tun *NativeTun) initNameCache() {
-	sysconn, err := tun.tunFile.SyscallConn()
-	if err != nil {
-		tun.nameErr = err
-		return
-	}
-	err = sysconn.Control(func(fd uintptr) {
-		var ifr [ifReqSize]byte
-		_, _, errno := unix.Syscall(
-			unix.SYS_IOCTL,
-			fd,
-			uintptr(unix.TUNGETIFF),
-			uintptr(unsafe.Pointer(&ifr[0])),
-		)
-		if errno != 0 {
-			tun.nameErr = errno
-			return
-		}
-		tun.nameCache = unix.ByteSliceToString(ifr[:])
-	})
-	if err != nil && tun.nameErr == nil {
-		tun.nameErr = err
-	}
-}
-
-func (tun *NativeTun) MTU() (int, error) {
-	name, err := tun.Name()
-	if err != nil {
-		return 0, err
-	}
-
-	// open datagram socket
-	fd, err := unix.Socket(
-		unix.AF_INET,
-		unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
-		0,
-	)
-	if err != nil {
-		return 0, err
-	}
-	defer unix.Close(fd)
-
-	var ifr [ifReqSize]byte
-	copy(ifr[:], name)
-
-	_, _, errno := unix.Syscall(
-		unix.SYS_IOCTL,
-		uintptr(fd),
-		uintptr(unix.SIOCGIFMTU),
-		uintptr(unsafe.Pointer(&ifr[0])),
-	)
-
-	if errno != 0 {
-		return 0, errno
-	}
-
-	return int(*(*uint32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ]))), nil
-}
-
-func (tun *NativeTun) Events() <-chan Event {
-	return tun.events
-}
-
-func (tun *NativeTun) Write(bufs [][]byte, offset int) (int, error) {
-	tun.writeOpMu.Lock()
-	defer func() {
-		tun.tcp4GROTable.reset()
-		tun.tcp6GROTable.reset()
-		tun.writeOpMu.Unlock()
-	}()
-	var (
-		errs  error
-		total int
-	)
-	tun.toWrite = tun.toWrite[:0]
-	if tun.vnetHdr {
-		err := handleGRO(bufs, offset, tun.tcp4GROTable, tun.tcp6GROTable, &tun.toWrite)
-		if err != nil {
-			return 0, err
-		}
-		offset -= virtioNetHdrLen
-	} else {
-		for i := range bufs {
-			tun.toWrite = append(tun.toWrite, i)
-		}
-	}
-	for _, bufsI := range tun.toWrite {
-		n, err := tun.tunFile.Write(bufs[bufsI][offset:])
-		if errors.Is(err, syscall.EBADFD) {
-			return total, os.ErrClosed
-		}
-		if err != nil {
-			errs = errors.Join(errs, err)
-		} else {
-			total += n
-		}
-	}
-	return total, errs
-}
-
-// handleVirtioRead splits in into bufs, leaving offset bytes at the front of
-// each buffer. It mutates sizes to reflect the size of each element of bufs,
-// and returns the number of packets read.
-func handleVirtioRead(in []byte, bufs [][]byte, sizes []int, offset int) (int, error) {
-	var hdr virtioNetHdr
-	if err := hdr.decode(in); err != nil {
-		return 0, err
-	}
-	in = in[virtioNetHdrLen:]
-	if hdr.gsoType == unix.VIRTIO_NET_HDR_GSO_NONE {
-		if hdr.flags&unix.VIRTIO_NET_HDR_F_NEEDS_CSUM != 0 {
-			if err := gsoNoneChecksum(in, hdr.csumStart, hdr.csumOffset); err != nil {
-				return 0, err
-			}
-		}
-		if len(in) > len(bufs[0][offset:]) {
-			return 0, fmt.Errorf("read len %d overflows bufs element len %d", len(in), len(bufs[0][offset:]))
-		}
-		n := copy(bufs[0][offset:], in)
-		sizes[0] = n
-		return 1, nil
-	}
-	if hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV4 && hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV6 {
-		return 0, fmt.Errorf("unsupported virtio GSO type: %d", hdr.gsoType)
-	}
-
-	ipVersion := in[0] >> 4
-	switch ipVersion {
-	case 4:
-		if hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV4 {
-			return 0, fmt.Errorf("ip header version: %d, GSO type: %d", ipVersion, hdr.gsoType)
-		}
-	case 6:
-		if hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV6 {
-			return 0, fmt.Errorf("ip header version: %d, GSO type: %d", ipVersion, hdr.gsoType)
-		}
-	default:
-		return 0, fmt.Errorf("invalid ip header version: %d", ipVersion)
-	}
-
-	if len(in) <= int(hdr.csumStart+12) {
-		return 0, errors.New("packet is too short")
-	}
-	tcpHLen := uint16(in[hdr.csumStart+12] >> 4 * 4)
-	if tcpHLen < 20 || tcpHLen > 60 {
-		return 0, fmt.Errorf("tcp header len is invalid: %d", tcpHLen)
-	}
-	hdr.hdrLen = hdr.csumStart + tcpHLen
-	if len(in) < int(hdr.hdrLen) {
-		return 0, fmt.Errorf("length of packet (%d) < virtioNetHdr.hdrLen (%d)", len(in), hdr.hdrLen)
-	}
-	if hdr.hdrLen < hdr.csumStart {
-		return 0, fmt.Errorf("virtioNetHdr.hdrLen (%d) < virtioNetHdr.csumStart (%d)", hdr.hdrLen, hdr.csumStart)
-	}
-	cSumAt := int(hdr.csumStart + hdr.csumOffset)
-	if cSumAt+1 >= len(in) {
-		return 0, fmt.Errorf("end of checksum offset (%d) exceeds packet length (%d)", cSumAt+1, len(in))
-	}
-
-	return tcpTSO(in, hdr, bufs, sizes, offset)
-}
-
-func (tun *NativeTun) Read(bufs [][]byte, sizes []int, offset int) (int, error) {
-	tun.readOpMu.Lock()
-	defer tun.readOpMu.Unlock()
-	select {
-	case err := <-tun.errors:
-		return 0, err
-	default:
-		readInto := bufs[0][offset:]
-		if tun.vnetHdr {
-			readInto = tun.readBuff[:]
-		}
-		n, err := tun.tunFile.Read(readInto)
-		if errors.Is(err, syscall.EBADFD) {
-			err = os.ErrClosed
-		}
-		if err != nil {
-			return 0, err
-		}
-		if tun.vnetHdr {
-			return handleVirtioRead(readInto[:n], bufs, sizes, offset)
-		}
-		sizes[0] = n
-		return 1, nil
-	}
-}