weird line breaks

* Fix incorrect CIDR construction in hostmap

* Introduce a regression test for incorrect hostmap CIDR

.github/workflows/gofmt.yml

@@ -16,9 +16,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Install goimports

.github/workflows/release.yml

@@ -12,9 +12,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
-          go-version: '1.24'
+          go-version: '1.25'
           check-latest: true
 
       - name: Build
@@ -35,9 +35,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
-          go-version: '1.24'
+          go-version: '1.25'
           check-latest: true
 
       - name: Build
@@ -68,9 +68,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
-          go-version: '1.24'
+          go-version: '1.25'
           check-latest: true
 
       - name: Import certificates

.github/workflows/smoke-extra.yml

@@ -22,9 +22,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version-file: 'go.mod'
+        go-version: '1.25'
         check-latest: true
 
     - name: add hashicorp source

.github/workflows/smoke.yml

@@ -20,9 +20,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: build

.github/workflows/test.yml

@@ -20,9 +20,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build
@@ -34,7 +34,7 @@ jobs:
     - name: golangci-lint
       uses: golangci/golangci-lint-action@v8
       with:
-        version: v2.1
+        version: v2.5
 
     - name: Test
       run: make test
@@ -58,9 +58,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build
@@ -79,9 +79,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.22'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build
@@ -100,9 +100,9 @@ jobs:
 
     - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build nebula
@@ -117,7 +117,7 @@ jobs:
     - name: golangci-lint
       uses: golangci/golangci-lint-action@v8
       with:
-        version: v2.1
+        version: v2.5
 
     - name: Test
       run: make test

cert/cert.go

@@ -58,6 +58,9 @@ type Certificate interface {
 	// PublicKey is the raw bytes to be used in asymmetric cryptographic operations.
 	PublicKey() []byte
 
+	// MarshalPublicKeyPEM is the value of PublicKey marshalled to PEM
+	MarshalPublicKeyPEM() []byte
+
 	// Curve identifies which curve was used for the PublicKey and Signature.
 	Curve() Curve
 

cert/cert_v1.go

@@ -83,6 +83,10 @@ func (c *certificateV1) PublicKey() []byte {
 	return c.details.publicKey
 }
 
+func (c *certificateV1) MarshalPublicKeyPEM() []byte {
+	return marshalCertPublicKeyToPEM(c)
+}
+
 func (c *certificateV1) Signature() []byte {
 	return c.signature
 }
@@ -110,8 +114,10 @@ func (c *certificateV1) CheckSignature(key []byte) bool {
 	case Curve_CURVE25519:
 		return ed25519.Verify(key, b, c.signature)
 	case Curve_P256:
-		x, y := elliptic.Unmarshal(elliptic.P256(), key)
+		pubKey, err := ecdsa.ParseUncompressedPublicKey(elliptic.P256(), key)
-		pubKey := &ecdsa.PublicKey{Curve: elliptic.P256(), X: x, Y: y}
+		if err != nil {
+			return false
+		}
 		hashed := sha256.Sum256(b)
 		return ecdsa.VerifyASN1(pubKey, hashed[:], c.signature)
 	default:

cert/cert_v1_test.go

@@ -1,6 +1,7 @@
 package cert
 
 import (
+	"crypto/ed25519"
 	"fmt"
 	"net/netip"
 	"testing"
@@ -13,6 +14,7 @@ import (
 )
 
 func TestCertificateV1_Marshal(t *testing.T) {
+	t.Parallel()
 	before := time.Now().Add(time.Second * -60).Round(time.Second)
 	after := time.Now().Add(time.Second * 60).Round(time.Second)
 	pubKey := []byte("1234567890abcedfghij1234567890ab")
@@ -60,6 +62,58 @@ func TestCertificateV1_Marshal(t *testing.T) {
 	assert.Equal(t, nc.Groups(), nc2.Groups())
 }
 
+func TestCertificateV1_PublicKeyPem(t *testing.T) {
+	t.Parallel()
+	before := time.Now().Add(time.Second * -60).Round(time.Second)
+	after := time.Now().Add(time.Second * 60).Round(time.Second)
+	pubKey := ed25519.PublicKey("1234567890abcedfghij1234567890ab")
+
+	nc := certificateV1{
+		details: detailsV1{
+			name:           "testing",
+			networks:       []netip.Prefix{},
+			unsafeNetworks: []netip.Prefix{},
+			groups:         []string{"test-group1", "test-group2", "test-group3"},
+			notBefore:      before,
+			notAfter:       after,
+			publicKey:      pubKey,
+			isCA:           false,
+			issuer:         "1234567890abcedfghij1234567890ab",
+		},
+		signature: []byte("1234567890abcedfghij1234567890ab"),
+	}
+
+	assert.Equal(t, Version1, nc.Version())
+	assert.Equal(t, Curve_CURVE25519, nc.Curve())
+	pubPem := "-----BEGIN NEBULA X25519 PUBLIC KEY-----\nMTIzNDU2Nzg5MGFiY2VkZmdoaWoxMjM0NTY3ODkwYWI=\n-----END NEBULA X25519 PUBLIC KEY-----\n"
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), pubPem)
+	assert.False(t, nc.IsCA())
+
+	nc.details.isCA = true
+	assert.Equal(t, Curve_CURVE25519, nc.Curve())
+	pubPem = "-----BEGIN NEBULA ED25519 PUBLIC KEY-----\nMTIzNDU2Nzg5MGFiY2VkZmdoaWoxMjM0NTY3ODkwYWI=\n-----END NEBULA ED25519 PUBLIC KEY-----\n"
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), pubPem)
+	assert.True(t, nc.IsCA())
+
+	pubP256KeyPem := []byte(`-----BEGIN NEBULA P256 PUBLIC KEY-----
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAAAAAAAAAAAAAAAAA=
+-----END NEBULA P256 PUBLIC KEY-----
+`)
+	pubP256Key, _, _, err := UnmarshalPublicKeyFromPEM(pubP256KeyPem)
+	require.NoError(t, err)
+	nc.details.curve = Curve_P256
+	nc.details.publicKey = pubP256Key
+	assert.Equal(t, Curve_P256, nc.Curve())
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), string(pubP256KeyPem))
+	assert.True(t, nc.IsCA())
+
+	nc.details.isCA = false
+	assert.Equal(t, Curve_P256, nc.Curve())
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), string(pubP256KeyPem))
+	assert.False(t, nc.IsCA())
+}
+
 func TestCertificateV1_Expired(t *testing.T) {
 	nc := certificateV1{
 		details: detailsV1{

cert/cert_v2.go

@@ -114,6 +114,10 @@ func (c *certificateV2) PublicKey() []byte {
 	return c.publicKey
 }
 
+func (c *certificateV2) MarshalPublicKeyPEM() []byte {
+	return marshalCertPublicKeyToPEM(c)
+}
+
 func (c *certificateV2) Signature() []byte {
 	return c.signature
 }
@@ -149,8 +153,10 @@ func (c *certificateV2) CheckSignature(key []byte) bool {
 	case Curve_CURVE25519:
 		return ed25519.Verify(key, b, c.signature)
 	case Curve_P256:
-		x, y := elliptic.Unmarshal(elliptic.P256(), key)
+		pubKey, err := ecdsa.ParseUncompressedPublicKey(elliptic.P256(), key)
-		pubKey := &ecdsa.PublicKey{Curve: elliptic.P256(), X: x, Y: y}
+		if err != nil {
+			return false
+		}
 		hashed := sha256.Sum256(b)
 		return ecdsa.VerifyASN1(pubKey, hashed[:], c.signature)
 	default:

cert/cert_v2_test.go

@@ -15,6 +15,7 @@ import (
 )
 
 func TestCertificateV2_Marshal(t *testing.T) {
+	t.Parallel()
 	before := time.Now().Add(time.Second * -60).Round(time.Second)
 	after := time.Now().Add(time.Second * 60).Round(time.Second)
 	pubKey := []byte("1234567890abcedfghij1234567890ab")
@@ -75,6 +76,58 @@ func TestCertificateV2_Marshal(t *testing.T) {
 	assert.Equal(t, nc.Groups(), nc2.Groups())
 }
 
+func TestCertificateV2_PublicKeyPem(t *testing.T) {
+	t.Parallel()
+	before := time.Now().Add(time.Second * -60).Round(time.Second)
+	after := time.Now().Add(time.Second * 60).Round(time.Second)
+	pubKey := ed25519.PublicKey("1234567890abcedfghij1234567890ab")
+
+	nc := certificateV2{
+		details: detailsV2{
+			name:           "testing",
+			networks:       []netip.Prefix{},
+			unsafeNetworks: []netip.Prefix{},
+			groups:         []string{"test-group1", "test-group2", "test-group3"},
+			notBefore:      before,
+			notAfter:       after,
+			isCA:           false,
+			issuer:         "1234567890abcedfghij1234567890ab",
+		},
+		publicKey: pubKey,
+		signature: []byte("1234567890abcedfghij1234567890ab"),
+	}
+
+	assert.Equal(t, Version2, nc.Version())
+	assert.Equal(t, Curve_CURVE25519, nc.Curve())
+	pubPem := "-----BEGIN NEBULA X25519 PUBLIC KEY-----\nMTIzNDU2Nzg5MGFiY2VkZmdoaWoxMjM0NTY3ODkwYWI=\n-----END NEBULA X25519 PUBLIC KEY-----\n"
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), pubPem)
+	assert.False(t, nc.IsCA())
+
+	nc.details.isCA = true
+	assert.Equal(t, Curve_CURVE25519, nc.Curve())
+	pubPem = "-----BEGIN NEBULA ED25519 PUBLIC KEY-----\nMTIzNDU2Nzg5MGFiY2VkZmdoaWoxMjM0NTY3ODkwYWI=\n-----END NEBULA ED25519 PUBLIC KEY-----\n"
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), pubPem)
+	assert.True(t, nc.IsCA())
+
+	pubP256KeyPem := []byte(`-----BEGIN NEBULA P256 PUBLIC KEY-----
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAAAAAAAAAAAAAAAAA=
+-----END NEBULA P256 PUBLIC KEY-----
+`)
+	pubP256Key, _, _, err := UnmarshalPublicKeyFromPEM(pubP256KeyPem)
+	require.NoError(t, err)
+	nc.curve = Curve_P256
+	nc.publicKey = pubP256Key
+	assert.Equal(t, Curve_P256, nc.Curve())
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), string(pubP256KeyPem))
+	assert.True(t, nc.IsCA())
+
+	nc.details.isCA = false
+	assert.Equal(t, Curve_P256, nc.Curve())
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), string(pubP256KeyPem))
+	assert.False(t, nc.IsCA())
+}
+
 func TestCertificateV2_Expired(t *testing.T) {
 	nc := certificateV2{
 		details: detailsV2{

cert/pem.go

@@ -7,19 +7,26 @@ import (
 	"golang.org/x/crypto/ed25519"
 )
 
-const (
+const ( //cert banners
-	CertificateBanner                = "NEBULA CERTIFICATE"
+	CertificateBanner   = "NEBULA CERTIFICATE"
-	CertificateV2Banner              = "NEBULA CERTIFICATE V2"
+	CertificateV2Banner = "NEBULA CERTIFICATE V2"
-	X25519PrivateKeyBanner           = "NEBULA X25519 PRIVATE KEY"
+)
-	X25519PublicKeyBanner            = "NEBULA X25519 PUBLIC KEY"
-	EncryptedEd25519PrivateKeyBanner = "NEBULA ED25519 ENCRYPTED PRIVATE KEY"
-	Ed25519PrivateKeyBanner          = "NEBULA ED25519 PRIVATE KEY"
-	Ed25519PublicKeyBanner           = "NEBULA ED25519 PUBLIC KEY"
 
-	P256PrivateKeyBanner               = "NEBULA P256 PRIVATE KEY"
+const ( //key-agreement-key banners
-	P256PublicKeyBanner                = "NEBULA P256 PUBLIC KEY"
+	X25519PrivateKeyBanner = "NEBULA X25519 PRIVATE KEY"
+	X25519PublicKeyBanner  = "NEBULA X25519 PUBLIC KEY"
+	P256PrivateKeyBanner   = "NEBULA P256 PRIVATE KEY"
+	P256PublicKeyBanner    = "NEBULA P256 PUBLIC KEY"
+)
+
+/* including "ECDSA" in the P256 banners is a clue that these keys should be used only for signing */
+const ( //signing key banners
 	EncryptedECDSAP256PrivateKeyBanner = "NEBULA ECDSA P256 ENCRYPTED PRIVATE KEY"
 	ECDSAP256PrivateKeyBanner          = "NEBULA ECDSA P256 PRIVATE KEY"
+	ECDSAP256PublicKeyBanner           = "NEBULA ECDSA P256 PUBLIC KEY"
+	EncryptedEd25519PrivateKeyBanner   = "NEBULA ED25519 ENCRYPTED PRIVATE KEY"
+	Ed25519PrivateKeyBanner            = "NEBULA ED25519 PRIVATE KEY"
+	Ed25519PublicKeyBanner             = "NEBULA ED25519 PUBLIC KEY"
 )
 
 // UnmarshalCertificateFromPEM will try to unmarshal the first pem block in a byte array, returning any non consumed
@@ -51,6 +58,16 @@ func UnmarshalCertificateFromPEM(b []byte) (Certificate, []byte, error) {
 
 }
 
+func marshalCertPublicKeyToPEM(c Certificate) []byte {
+	if c.IsCA() {
+		return MarshalSigningPublicKeyToPEM(c.Curve(), c.PublicKey())
+	} else {
+		return MarshalPublicKeyToPEM(c.Curve(), c.PublicKey())
+	}
+}
+
+// MarshalPublicKeyToPEM returns a PEM representation of a public key used for ECDH.
+// if your public key came from a certificate, prefer Certificate.PublicKeyPEM() if possible, to avoid mistakes!
 func MarshalPublicKeyToPEM(curve Curve, b []byte) []byte {
 	switch curve {
 	case Curve_CURVE25519:
@@ -62,6 +79,19 @@ func MarshalPublicKeyToPEM(curve Curve, b []byte) []byte {
 	}
 }
 
+// MarshalSigningPublicKeyToPEM returns a PEM representation of a public key used for signing.
+// if your public key came from a certificate, prefer Certificate.PublicKeyPEM() if possible, to avoid mistakes!
+func MarshalSigningPublicKeyToPEM(curve Curve, b []byte) []byte {
+	switch curve {
+	case Curve_CURVE25519:
+		return pem.EncodeToMemory(&pem.Block{Type: Ed25519PublicKeyBanner, Bytes: b})
+	case Curve_P256:
+		return pem.EncodeToMemory(&pem.Block{Type: P256PublicKeyBanner, Bytes: b})
+	default:
+		return nil
+	}
+}
+
 func UnmarshalPublicKeyFromPEM(b []byte) ([]byte, []byte, Curve, error) {
 	k, r := pem.Decode(b)
 	if k == nil {
@@ -73,7 +103,7 @@ func UnmarshalPublicKeyFromPEM(b []byte) ([]byte, []byte, Curve, error) {
 	case X25519PublicKeyBanner, Ed25519PublicKeyBanner:
 		expectedLen = 32
 		curve = Curve_CURVE25519
-	case P256PublicKeyBanner:
+	case P256PublicKeyBanner, ECDSAP256PublicKeyBanner:
 		// Uncompressed
 		expectedLen = 65
 		curve = Curve_P256

cert/pem_test.go

@@ -177,6 +177,7 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 }
 
 func TestUnmarshalPublicKeyFromPEM(t *testing.T) {
+	t.Parallel()
 	pubKey := []byte(`# A good key
 -----BEGIN NEBULA ED25519 PUBLIC KEY-----
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
@@ -230,6 +231,7 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 }
 
 func TestUnmarshalX25519PublicKey(t *testing.T) {
+	t.Parallel()
 	pubKey := []byte(`# A good key
 -----BEGIN NEBULA X25519 PUBLIC KEY-----
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
@@ -240,6 +242,12 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAA=
 -----END NEBULA P256 PUBLIC KEY-----
+`)
+	oldPubP256Key := []byte(`# A good key
+-----BEGIN NEBULA ECDSA P256 PUBLIC KEY-----
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAAAAAAAAAAAAAAAAA=
+-----END NEBULA ECDSA P256 PUBLIC KEY-----
 `)
 	shortKey := []byte(`# A short key
 -----BEGIN NEBULA X25519 PUBLIC KEY-----
@@ -256,15 +264,22 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 -END NEBULA X25519 PUBLIC KEY-----`)
 
-	keyBundle := appendByteSlices(pubKey, pubP256Key, shortKey, invalidBanner, invalidPem)
+	keyBundle := appendByteSlices(pubKey, pubP256Key, oldPubP256Key, shortKey, invalidBanner, invalidPem)
 
 	// Success test case
 	k, rest, curve, err := UnmarshalPublicKeyFromPEM(keyBundle)
 	assert.Len(t, k, 32)
 	require.NoError(t, err)
-	assert.Equal(t, rest, appendByteSlices(pubP256Key, shortKey, invalidBanner, invalidPem))
+	assert.Equal(t, rest, appendByteSlices(pubP256Key, oldPubP256Key, shortKey, invalidBanner, invalidPem))
 	assert.Equal(t, Curve_CURVE25519, curve)
 
+	// Success test case
+	k, rest, curve, err = UnmarshalPublicKeyFromPEM(rest)
+	assert.Len(t, k, 65)
+	require.NoError(t, err)
+	assert.Equal(t, rest, appendByteSlices(oldPubP256Key, shortKey, invalidBanner, invalidPem))
+	assert.Equal(t, Curve_P256, curve)
+
 	// Success test case
 	k, rest, curve, err = UnmarshalPublicKeyFromPEM(rest)
 	assert.Len(t, k, 65)

cert/sign.go

@@ -7,7 +7,6 @@ import (
 	"crypto/rand"
 	"crypto/sha256"
 	"fmt"
-	"math/big"
 	"net/netip"
 	"time"
 )
@@ -55,15 +54,10 @@ func (t *TBSCertificate) Sign(signer Certificate, curve Curve, key []byte) (Cert
 		}
 		return t.SignWith(signer, curve, sp)
 	case Curve_P256:
-		pk := &ecdsa.PrivateKey{
+		pk, err := ecdsa.ParseRawPrivateKey(elliptic.P256(), key)
-			PublicKey: ecdsa.PublicKey{
+		if err != nil {
-				Curve: elliptic.P256(),
+			return nil, err
-			},
-			// ref: https://github.com/golang/go/blob/go1.19/src/crypto/x509/sec1.go#L95
-			D: new(big.Int).SetBytes(key),
 		}
-		// ref: https://github.com/golang/go/blob/go1.19/src/crypto/x509/sec1.go#L119
-		pk.X, pk.Y = pk.Curve.ScalarBaseMult(key)
 		sp := func(certBytes []byte) ([]byte, error) {
 			// We need to hash first for ECDSA
 			// - https://pkg.go.dev/crypto/ecdsa#SignASN1

connection_manager_test.go

@@ -22,7 +22,7 @@ func newTestLighthouse() *LightHouse {
 		addrMap:   map[netip.Addr]*RemoteList{},
 		queryChan: make(chan netip.Addr, 10),
 	}
-	lighthouses := map[netip.Addr]struct{}{}
+	lighthouses := []netip.Addr{}
 	staticList := map[netip.Addr]struct{}{}
 
 	lh.lighthouses.Store(&lighthouses)
@@ -446,6 +446,10 @@ func (d *dummyCert) PublicKey() []byte {
 	return d.publicKey
 }
 
+func (d *dummyCert) MarshalPublicKeyPEM() []byte {
+	return cert.MarshalPublicKeyToPEM(d.curve, d.publicKey)
+}
+
 func (d *dummyCert) Signature() []byte {
 	return d.signature
 }

e2e/helpers_test.go

@@ -29,8 +29,6 @@ type m = map[string]any
 
 // newSimpleServer creates a nebula instance with many assumptions
 func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name string, sVpnNetworks string, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
-	l := NewTestLogger()
-
 	var vpnNetworks []netip.Prefix
 	for _, sn := range strings.Split(sVpnNetworks, ",") {
 		vpnIpNet, err := netip.ParsePrefix(strings.TrimSpace(sn))
@@ -56,6 +54,25 @@ func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name
 		budpIp[3] = 239
 		udpAddr = netip.AddrPortFrom(netip.AddrFrom16(budpIp), 4242)
 	}
+	return newSimpleServerWithUdp(v, caCrt, caKey, name, sVpnNetworks, udpAddr, overrides)
+}
+
+func newSimpleServerWithUdp(v cert.Version, caCrt cert.Certificate, caKey []byte, name string, sVpnNetworks string, udpAddr netip.AddrPort, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
+	l := NewTestLogger()
+
+	var vpnNetworks []netip.Prefix
+	for _, sn := range strings.Split(sVpnNetworks, ",") {
+		vpnIpNet, err := netip.ParsePrefix(strings.TrimSpace(sn))
+		if err != nil {
+			panic(err)
+		}
+		vpnNetworks = append(vpnNetworks, vpnIpNet)
+	}
+
+	if len(vpnNetworks) == 0 {
+		panic("no vpn networks")
+	}
+
 	_, _, myPrivKey, myPEM := cert_test.NewTestCert(v, cert.Curve_CURVE25519, caCrt, caKey, name, time.Now(), time.Now().Add(5*time.Minute), vpnNetworks, nil, []string{})
 
 	caB, err := caCrt.MarshalPEM()

e2e/tunnels_test.go

@@ -4,6 +4,7 @@
 package e2e
 
 import (
+	"net/netip"
 	"testing"
 	"time"
 
@@ -55,3 +56,50 @@ func TestDropInactiveTunnels(t *testing.T) {
 	myControl.Stop()
 	theirControl.Stop()
 }
+
+func TestCrossStackRelaysWork(t *testing.T) {
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	myControl, myVpnIpNet, _, _ := newSimpleServer(cert.Version2, ca, caKey, "me     ", "10.128.0.1/24,fc00::1/64", m{"relay": m{"use_relays": true}})
+	relayControl, relayVpnIpNet, relayUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "relay  ", "10.128.0.128/24,fc00::128/64", m{"relay": m{"am_relay": true}})
+	theirUdp := netip.MustParseAddrPort("10.0.0.2:4242")
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServerWithUdp(cert.Version2, ca, caKey, "them   ", "fc00::2/64", theirUdp, m{"relay": m{"use_relays": true}})
+
+	//myVpnV4 := myVpnIpNet[0]
+	myVpnV6 := myVpnIpNet[1]
+	relayVpnV4 := relayVpnIpNet[0]
+	relayVpnV6 := relayVpnIpNet[1]
+	theirVpnV6 := theirVpnIpNet[0]
+
+	// Teach my how to get to the relay and that their can be reached via the relay
+	myControl.InjectLightHouseAddr(relayVpnV4.Addr(), relayUdpAddr)
+	myControl.InjectLightHouseAddr(relayVpnV6.Addr(), relayUdpAddr)
+	myControl.InjectRelays(theirVpnV6.Addr(), []netip.Addr{relayVpnV6.Addr()})
+	relayControl.InjectLightHouseAddr(theirVpnV6.Addr(), theirUdpAddr)
+
+	// Build a router so we don't have to reason who gets which packet
+	r := router.NewR(t, myControl, relayControl, theirControl)
+	defer r.RenderFlow()
+
+	// Start the servers
+	myControl.Start()
+	relayControl.Start()
+	theirControl.Start()
+
+	t.Log("Trigger a handshake from me to them via the relay")
+	myControl.InjectTunUDPPacket(theirVpnV6.Addr(), 80, myVpnV6.Addr(), 80, []byte("Hi from me"))
+
+	p := r.RouteForAllUntilTxTun(theirControl)
+	r.Log("Assert the tunnel works")
+	assertUdpPacket(t, []byte("Hi from me"), p, myVpnV6.Addr(), theirVpnV6.Addr(), 80, 80)
+
+	t.Log("reply?")
+	theirControl.InjectTunUDPPacket(myVpnV6.Addr(), 80, theirVpnV6.Addr(), 80, []byte("Hi from them"))
+	p = r.RouteForAllUntilTxTun(myControl)
+	assertUdpPacket(t, []byte("Hi from them"), p, theirVpnV6.Addr(), myVpnV6.Addr(), 80, 80)
+
+	r.RenderHostmaps("Final hostmaps", myControl, relayControl, theirControl)
+	//t.Log("finish up")
+	//myControl.Stop()
+	//theirControl.Stop()
+	//relayControl.Stop()
+}

firewall_test.go

@@ -692,6 +692,50 @@ func TestFirewall_DropConntrackReload(t *testing.T) {
 	assert.Equal(t, fw.Drop(p, false, &h, cp, nil), ErrNoMatchingRule)
 }
 
+func TestFirewall_DropIPSpoofing(t *testing.T) {
+	l := test.NewLogger()
+	ob := &bytes.Buffer{}
+	l.SetOutput(ob)
+
+	c := cert.CachedCertificate{
+		Certificate: &dummyCert{
+			name:     "host-owner",
+			networks: []netip.Prefix{netip.MustParsePrefix("192.0.2.1/24")},
+		},
+	}
+
+	c1 := cert.CachedCertificate{
+		Certificate: &dummyCert{
+			name:           "host",
+			networks:       []netip.Prefix{netip.MustParsePrefix("192.0.2.2/24")},
+			unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("198.51.100.0/24")},
+		},
+	}
+	h1 := HostInfo{
+		ConnectionState: &ConnectionState{
+			peerCert: &c1,
+		},
+		vpnAddrs: []netip.Addr{c1.Certificate.Networks()[0].Addr()},
+	}
+	h1.buildNetworks(c1.Certificate.Networks(), c1.Certificate.UnsafeNetworks())
+
+	fw := NewFirewall(l, time.Second, time.Minute, time.Hour, c.Certificate)
+
+	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 1, 1, []string{}, "", netip.Prefix{}, netip.Prefix{}, "", ""))
+	cp := cert.NewCAPool()
+
+	// Packet spoofed by `c1`. Note that the remote addr is not a valid one.
+	p := firewall.Packet{
+		LocalAddr:  netip.MustParseAddr("192.0.2.1"),
+		RemoteAddr: netip.MustParseAddr("192.0.2.3"),
+		LocalPort:  1,
+		RemotePort: 1,
+		Protocol:   firewall.ProtoUDP,
+		Fragment:   false,
+	}
+	assert.Equal(t, fw.Drop(p, true, &h1, cp, nil), ErrInvalidRemoteIP)
+}
+
 func BenchmarkLookup(b *testing.B) {
 	ml := func(m map[string]struct{}, a [][]string) {
 		for n := 0; n < b.N; n++ {

go.mod

@@ -1,8 +1,6 @@
 module github.com/slackhq/nebula
 
-go 1.23.0
+go 1.25
-
-toolchain go1.24.1
 
 require (
 	dario.cat/mergo v1.0.2

handshake_ix.go

@@ -459,7 +459,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	f.connectionManager.AddTrafficWatch(hostinfo)
 
-	hostinfo.remotes.ResetBlockedRemotes()
+	hostinfo.remotes.RefreshFromHandshake(vpnAddrs)
 
 	return
 }
@@ -667,7 +667,7 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 		f.cachedPacketMetrics.sent.Inc(int64(len(hh.packetStore)))
 	}
 
-	hostinfo.remotes.ResetBlockedRemotes()
+	hostinfo.remotes.RefreshFromHandshake(vpnAddrs)
 	f.metricHandshakes.Update(duration)
 
 	return false

handshake_manager.go

@@ -292,6 +292,7 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 					idx, err := AddRelay(hm.l, relayHostInfo, hm.mainHostMap, vpnIp, nil, TerminalType, Requested)
 					if err != nil {
 						hostinfo.logger(hm.l).WithField("relay", relay.String()).WithError(err).Info("Failed to add relay to hostmap")
+						continue
 					}
 
 					m := NebulaControl{
@@ -301,37 +302,25 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 
 					switch relayHostInfo.GetCert().Certificate.Version() {
 					case cert.Version1:
-						if !hm.f.myVpnAddrs[0].Is4() {
+						err = buildRelayInfoCertV1(&m, hm.f.myVpnNetworks, vpnIp)
-							hostinfo.logger(hm.l).Error("can not establish v1 relay with a v6 network because the relay is not running a current nebula version")
-							continue
-						}
-
-						if !vpnIp.Is4() {
-							hostinfo.logger(hm.l).Error("can not establish v1 relay with a v6 remote network because the relay is not running a current nebula version")
-							continue
-						}
-
-						b := hm.f.myVpnAddrs[0].As4()
-						m.OldRelayFromAddr = binary.BigEndian.Uint32(b[:])
-						b = vpnIp.As4()
-						m.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
 					case cert.Version2:
-						m.RelayFromAddr = netAddrToProtoAddr(hm.f.myVpnAddrs[0])
+						err = buildRelayInfoCertV2(&m, hm.f.myVpnNetworks, vpnIp)
-						m.RelayToAddr = netAddrToProtoAddr(vpnIp)
 					default:
-						hostinfo.logger(hm.l).Error("Unknown certificate version found while creating relay")
+						err = errors.New("unknown certificate version found while creating relay")
+					}
+					if err != nil {
+						hostinfo.logger(hm.l).WithError(err).Error("Refusing to relay")
 						continue
 					}
 
 					msg, err := m.Marshal()
 					if err != nil {
-						hostinfo.logger(hm.l).
+						hostinfo.logger(hm.l).WithError(err).
-							WithError(err).
 							Error("Failed to marshal Control message to create relay")
 					} else {
 						hm.f.SendMessageToHostInfo(header.Control, 0, relayHostInfo, msg, make([]byte, 12), make([]byte, mtu))
 						hm.l.WithFields(logrus.Fields{
-							"relayFrom":           hm.f.myVpnAddrs[0],
+							"relayFrom":           m.GetRelayFrom(),
 							"relayTo":             vpnIp,
 							"initiatorRelayIndex": idx,
 							"relay":               relay}).
@@ -357,39 +346,27 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 					InitiatorRelayIndex: existingRelay.LocalIndex,
 				}
 
+				var err error
 				switch relayHostInfo.GetCert().Certificate.Version() {
 				case cert.Version1:
-					if !hm.f.myVpnAddrs[0].Is4() {
+					err = buildRelayInfoCertV1(&m, hm.f.myVpnNetworks, vpnIp)
-						hostinfo.logger(hm.l).Error("can not establish v1 relay with a v6 network because the relay is not running a current nebula version")
-						continue
-					}
-
-					if !vpnIp.Is4() {
-						hostinfo.logger(hm.l).Error("can not establish v1 relay with a v6 remote network because the relay is not running a current nebula version")
-						continue
-					}
-
-					b := hm.f.myVpnAddrs[0].As4()
-					m.OldRelayFromAddr = binary.BigEndian.Uint32(b[:])
-					b = vpnIp.As4()
-					m.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
 				case cert.Version2:
-					m.RelayFromAddr = netAddrToProtoAddr(hm.f.myVpnAddrs[0])
+					err = buildRelayInfoCertV2(&m, hm.f.myVpnNetworks, vpnIp)
-					m.RelayToAddr = netAddrToProtoAddr(vpnIp)
 				default:
-					hostinfo.logger(hm.l).Error("Unknown certificate version found while creating relay")
+					err = errors.New("unknown certificate version found while creating relay")
+				}
+				if err != nil {
+					hostinfo.logger(hm.l).WithError(err).Error("Refusing to relay")
 					continue
 				}
 				msg, err := m.Marshal()
 				if err != nil {
-					hostinfo.logger(hm.l).
+					hostinfo.logger(hm.l).WithError(err).Error("Failed to marshal Control message to create relay")
-						WithError(err).
-						Error("Failed to marshal Control message to create relay")
 				} else {
 					// This must send over the hostinfo, not over hm.Hosts[ip]
 					hm.f.SendMessageToHostInfo(header.Control, 0, relayHostInfo, msg, make([]byte, 12), make([]byte, mtu))
 					hm.l.WithFields(logrus.Fields{
-						"relayFrom":           hm.f.myVpnAddrs[0],
+						"relayFrom":           m.GetRelayFrom(),
 						"relayTo":             vpnIp,
 						"initiatorRelayIndex": existingRelay.LocalIndex,
 						"relay":               relay}).
@@ -724,3 +701,32 @@ func generateIndex(l *logrus.Logger) (uint32, error) {
 func hsTimeout(tries int64, interval time.Duration) time.Duration {
 	return time.Duration(tries / 2 * ((2 * int64(interval)) + (tries-1)*int64(interval)))
 }
+
+var errNoRelayTooOld = errors.New("can not establish v1 relay with a v6 network because the relay is not running a current nebula version")
+
+func buildRelayInfoCertV1(m *NebulaControl, myVpnNetworks []netip.Prefix, peerVpnIp netip.Addr) error {
+	relayFrom := myVpnNetworks[0].Addr()
+	if !relayFrom.Is4() {
+		return errNoRelayTooOld
+	}
+	if !peerVpnIp.Is4() {
+		return errNoRelayTooOld
+	}
+
+	b := relayFrom.As4()
+	m.OldRelayFromAddr = binary.BigEndian.Uint32(b[:])
+	b = peerVpnIp.As4()
+	m.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
+	return nil
+}
+
+func buildRelayInfoCertV2(m *NebulaControl, myVpnNetworks []netip.Prefix, peerVpnIp netip.Addr) error {
+	for i := range myVpnNetworks {
+		if myVpnNetworks[i].Contains(peerVpnIp) {
+			m.RelayFromAddr = netAddrToProtoAddr(myVpnNetworks[i].Addr())
+			m.RelayToAddr = netAddrToProtoAddr(peerVpnIp)
+			return nil
+		}
+	}
+	return errors.New("cannot establish relay, no networks in common")
+}

hostmap.go

@@ -512,13 +512,16 @@ func (hm *HostMap) QueryVpnAddr(vpnIp netip.Addr) *HostInfo {
 	return hm.queryVpnAddr(vpnIp, nil)
 }
 
+var errUnableToFindHost = errors.New("unable to find host")
+var errUnableToFindHostWithRelay = errors.New("unable to find host with relay")
+
 func (hm *HostMap) QueryVpnAddrsRelayFor(targetIps []netip.Addr, relayHostIp netip.Addr) (*HostInfo, *Relay, error) {
 	hm.RLock()
 	defer hm.RUnlock()
 
 	h, ok := hm.Hosts[relayHostIp]
 	if !ok {
-		return nil, nil, errors.New("unable to find host")
+		return nil, nil, errUnableToFindHost
 	}
 
 	for h != nil {
@@ -531,7 +534,7 @@ func (hm *HostMap) QueryVpnAddrsRelayFor(targetIps []netip.Addr, relayHostIp net
 		h = h.next
 	}
 
-	return nil, nil, errors.New("unable to find host with relay")
+	return nil, nil, errUnableToFindHostWithRelay
 }
 
 func (hm *HostMap) unlockedDisestablishVpnAddrRelayFor(hi *HostInfo) {
@@ -738,7 +741,8 @@ func (i *HostInfo) buildNetworks(networks, unsafeNetworks []netip.Prefix) {
 
 	i.networks = new(bart.Lite)
 	for _, network := range networks {
-		i.networks.Insert(network)
+		nprefix := netip.PrefixFrom(network.Addr(), network.Addr().BitLen())
+		i.networks.Insert(nprefix)
 	}
 
 	for _, network := range unsafeNetworks {

lighthouse.go

@@ -57,7 +57,7 @@ type LightHouse struct {
 	// staticList exists to avoid having a bool in each addrMap entry
 	// since static should be rare
 	staticList  atomic.Pointer[map[netip.Addr]struct{}]
-	lighthouses atomic.Pointer[map[netip.Addr]struct{}]
+	lighthouses atomic.Pointer[[]netip.Addr]
 
 	interval     atomic.Int64
 	updateCancel context.CancelFunc
@@ -108,7 +108,7 @@ func NewLightHouseFromConfig(ctx context.Context, l *logrus.Logger, c *config.C,
 		queryChan:          make(chan netip.Addr, c.GetUint32("handshakes.query_buffer", 64)),
 		l:                  l,
 	}
-	lighthouses := make(map[netip.Addr]struct{})
+	lighthouses := make([]netip.Addr, 0)
 	h.lighthouses.Store(&lighthouses)
 	staticList := make(map[netip.Addr]struct{})
 	h.staticList.Store(&staticList)
@@ -144,7 +144,7 @@ func (lh *LightHouse) GetStaticHostList() map[netip.Addr]struct{} {
 	return *lh.staticList.Load()
 }
 
-func (lh *LightHouse) GetLighthouses() map[netip.Addr]struct{} {
+func (lh *LightHouse) GetLighthouses() []netip.Addr {
 	return *lh.lighthouses.Load()
 }
 
@@ -307,13 +307,12 @@ func (lh *LightHouse) reload(c *config.C, initial bool) error {
 	}
 
 	if initial || c.HasChanged("lighthouse.hosts") {
-		lhMap := make(map[netip.Addr]struct{})
+		lhList, err := lh.parseLighthouses(c)
-		err := lh.parseLighthouses(c, lhMap)
 		if err != nil {
 			return err
 		}
 
-		lh.lighthouses.Store(&lhMap)
+		lh.lighthouses.Store(&lhList)
 		if !initial {
 			//NOTE: we are not tearing down existing lighthouse connections because they might be used for non lighthouse traffic
 			lh.l.Info("lighthouse.hosts has changed")
@@ -347,36 +346,37 @@ func (lh *LightHouse) reload(c *config.C, initial bool) error {
 	return nil
 }
 
-func (lh *LightHouse) parseLighthouses(c *config.C, lhMap map[netip.Addr]struct{}) error {
+func (lh *LightHouse) parseLighthouses(c *config.C) ([]netip.Addr, error) {
 	lhs := c.GetStringSlice("lighthouse.hosts", []string{})
 	if lh.amLighthouse && len(lhs) != 0 {
 		lh.l.Warn("lighthouse.am_lighthouse enabled on node but upstream lighthouses exist in config")
 	}
+	out := make([]netip.Addr, len(lhs))
 
 	for i, host := range lhs {
 		addr, err := netip.ParseAddr(host)
 		if err != nil {
-			return util.NewContextualError("Unable to parse lighthouse host entry", m{"host": host, "entry": i + 1}, err)
+			return nil, util.NewContextualError("Unable to parse lighthouse host entry", m{"host": host, "entry": i + 1}, err)
 		}
 
 		if !lh.myVpnNetworksTable.Contains(addr) {
-			return util.NewContextualError("lighthouse host is not in our networks, invalid", m{"vpnAddr": addr, "networks": lh.myVpnNetworks}, nil)
+			return nil, util.NewContextualError("lighthouse host is not in our networks, invalid", m{"vpnAddr": addr, "networks": lh.myVpnNetworks}, nil)
 		}
-		lhMap[addr] = struct{}{}
+		out[i] = addr
 	}
 
-	if !lh.amLighthouse && len(lhMap) == 0 {
+	if !lh.amLighthouse && len(out) == 0 {
 		lh.l.Warn("No lighthouse.hosts configured, this host will only be able to initiate tunnels with static_host_map entries")
 	}
 
 	staticList := lh.GetStaticHostList()
-	for lhAddr, _ := range lhMap {
+	for i := range out {
-		if _, ok := staticList[lhAddr]; !ok {
+		if _, ok := staticList[out[i]]; !ok {
-			return fmt.Errorf("lighthouse %s does not have a static_host_map entry", lhAddr)
+			return nil, fmt.Errorf("lighthouse %s does not have a static_host_map entry", out[i])
 		}
 	}
 
-	return nil
+	return out, nil
 }
 
 func getStaticMapCadence(c *config.C) (time.Duration, error) {
@@ -487,7 +487,7 @@ func (lh *LightHouse) QueryCache(vpnAddrs []netip.Addr) *RemoteList {
 	lh.Lock()
 	defer lh.Unlock()
 	// Add an entry if we don't already have one
-	return lh.unlockedGetRemoteList(vpnAddrs)
+	return lh.unlockedGetRemoteList(vpnAddrs) //todo CERT-V2 this contains addrmap lookups we could potentially skip
 }
 
 // queryAndPrepMessage is a lock helper on RemoteList, assisting the caller to build a lighthouse message containing
@@ -570,7 +570,7 @@ func (lh *LightHouse) addStaticRemotes(i int, d time.Duration, network string, t
 	am.unlockedSetHostnamesResults(hr)
 
 	for _, addrPort := range hr.GetAddrs() {
-		if !lh.shouldAdd(vpnAddr, addrPort.Addr()) {
+		if !lh.shouldAdd([]netip.Addr{vpnAddr}, addrPort.Addr()) {
 			continue
 		}
 		switch {
@@ -645,18 +645,17 @@ func (lh *LightHouse) unlockedGetRemoteList(allAddrs []netip.Addr) *RemoteList {
 		}
 	}
 
-	//TODO lighthouse.remote_allow_ranges is almost certainly broken in a multiple-address-per-cert scenario
+	am := NewRemoteList(allAddrs, lh.shouldAdd)
-	am := NewRemoteList(allAddrs, func(a netip.Addr) bool { return lh.shouldAdd(allAddrs[0], a) })
 	for _, addr := range allAddrs {
 		lh.addrMap[addr] = am
 	}
 	return am
 }
 
-func (lh *LightHouse) shouldAdd(vpnAddr netip.Addr, to netip.Addr) bool {
+func (lh *LightHouse) shouldAdd(vpnAddrs []netip.Addr, to netip.Addr) bool {
-	allow := lh.GetRemoteAllowList().Allow(vpnAddr, to)
+	allow := lh.GetRemoteAllowList().AllowAll(vpnAddrs, to)
 	if lh.l.Level >= logrus.TraceLevel {
-		lh.l.WithField("vpnAddr", vpnAddr).WithField("udpAddr", to).WithField("allow", allow).
+		lh.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", to).WithField("allow", allow).
 			Trace("remoteAllowList.Allow")
 	}
 	if !allow {
@@ -711,15 +710,22 @@ func (lh *LightHouse) unlockedShouldAddV6(vpnAddr netip.Addr, to *V6AddrPort) bo
 }
 
 func (lh *LightHouse) IsLighthouseAddr(vpnAddr netip.Addr) bool {
-	_, ok := lh.GetLighthouses()[vpnAddr]
+	l := lh.GetLighthouses()
-	return ok
+	for i := range l {
+		if l[i] == vpnAddr {
+			return true
+		}
+	}
+	return false
 }
 
-func (lh *LightHouse) IsAnyLighthouseAddr(vpnAddr []netip.Addr) bool {
+func (lh *LightHouse) IsAnyLighthouseAddr(vpnAddrs []netip.Addr) bool {
 	l := lh.GetLighthouses()
-	for _, a := range vpnAddr {
+	for i := range vpnAddrs {
-		if _, ok := l[a]; ok {
+		for j := range l {
-			return true
+			if l[j] == vpnAddrs[i] {
+				return true
+			}
 		}
 	}
 	return false
@@ -761,7 +767,7 @@ func (lh *LightHouse) innerQueryServer(addr netip.Addr, nb, out []byte) {
 	queried := 0
 	lighthouses := lh.GetLighthouses()
 
-	for lhVpnAddr := range lighthouses {
+	for _, lhVpnAddr := range lighthouses {
 		hi := lh.ifce.GetHostInfo(lhVpnAddr)
 		if hi != nil {
 			v = hi.ConnectionState.myCert.Version()
@@ -879,7 +885,7 @@ func (lh *LightHouse) SendUpdate() {
 	updated := 0
 	lighthouses := lh.GetLighthouses()
 
-	for lhVpnAddr := range lighthouses {
+	for _, lhVpnAddr := range lighthouses {
 		var v cert.Version
 		hi := lh.ifce.GetHostInfo(lhVpnAddr)
 		if hi != nil {
@@ -937,7 +943,6 @@ func (lh *LightHouse) SendUpdate() {
 						V4AddrPorts:   v4,
 						V6AddrPorts:   v6,
 						RelayVpnAddrs: relays,
-						VpnAddr:       netAddrToProtoAddr(lh.myVpnNetworks[0].Addr()),
 					},
 				}
 
@@ -1060,7 +1065,16 @@ func (lhh *LightHouseHandler) handleHostQuery(n *NebulaMeta, fromVpnAddrs []neti
 	queryVpnAddr, useVersion, err := n.Details.GetVpnAddrAndVersion()
 	if err != nil {
 		if lhh.l.Level >= logrus.DebugLevel {
-			lhh.l.WithField("from", fromVpnAddrs).WithField("details", n.Details).Debugln("Dropping malformed HostQuery")
+			lhh.l.WithField("from", fromVpnAddrs).WithField("details", n.Details).
+				Debugln("Dropping malformed HostQuery")
+		}
+		return
+	}
+	if useVersion == cert.Version1 && queryVpnAddr.Is6() {
+		// this case really shouldn't be possible to represent, but reject it anyway.
+		if lhh.l.Level >= logrus.DebugLevel {
+			lhh.l.WithField("vpnAddrs", fromVpnAddrs).WithField("queryVpnAddr", queryVpnAddr).
+				Debugln("invalid vpn addr for v1 handleHostQuery")
 		}
 		return
 	}
@@ -1069,9 +1083,6 @@ func (lhh *LightHouseHandler) handleHostQuery(n *NebulaMeta, fromVpnAddrs []neti
 		n = lhh.resetMeta()
 		n.Type = NebulaMeta_HostQueryReply
 		if useVersion == cert.Version1 {
-			if !queryVpnAddr.Is4() {
-				return 0, fmt.Errorf("invalid vpn addr for v1 handleHostQuery")
-			}
 			b := queryVpnAddr.As4()
 			n.Details.OldVpnAddr = binary.BigEndian.Uint32(b[:])
 		} else {
@@ -1231,16 +1242,24 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 		return
 	}
 
-	detailsVpnAddr, useVersion, err := n.Details.GetVpnAddrAndVersion()
+	// not using GetVpnAddrAndVersion because we don't want to error on a blank detailsVpnAddr
-	if err != nil {
+	var detailsVpnAddr netip.Addr
-		if lhh.l.Level >= logrus.DebugLevel {
+	var useVersion cert.Version
-			lhh.l.WithField("details", n.Details).WithError(err).Debugln("dropping invalid HostUpdateNotification")
+	if n.Details.OldVpnAddr != 0 { //v1 always sets this field
-		}
+		b := [4]byte{}
+		binary.BigEndian.PutUint32(b[:], n.Details.OldVpnAddr)
+		detailsVpnAddr = netip.AddrFrom4(b)
+		useVersion = cert.Version1
+	} else if n.Details.VpnAddr != nil { //this field is "optional" in v2, but if it's set, we should enforce it
+		detailsVpnAddr = protoAddrToNetAddr(n.Details.VpnAddr)
+		useVersion = cert.Version2
+	} else {
+		detailsVpnAddr = netip.Addr{}
+		useVersion = cert.Version2
 	}
 
-	//TODO: CERT-V2 why do we care about the vpnAddr in the packet? We know where it came from, right?
+	//Simple check that the host sent this not someone else, if detailsVpnAddr is filled
-	//Simple check that the host sent this not someone else
+	if detailsVpnAddr.IsValid() && !slices.Contains(fromVpnAddrs, detailsVpnAddr) {
-	if !slices.Contains(fromVpnAddrs, detailsVpnAddr) {
 		if lhh.l.Level >= logrus.DebugLevel {
 			lhh.l.WithField("vpnAddrs", fromVpnAddrs).WithField("answer", detailsVpnAddr).Debugln("Host sent invalid update")
 		}
@@ -1254,24 +1273,24 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 	am.Lock()
 	lhh.lh.Unlock()
 
-	am.unlockedSetV4(fromVpnAddrs[0], detailsVpnAddr, n.Details.V4AddrPorts, lhh.lh.unlockedShouldAddV4)
+	am.unlockedSetV4(fromVpnAddrs[0], fromVpnAddrs[0], n.Details.V4AddrPorts, lhh.lh.unlockedShouldAddV4)
-	am.unlockedSetV6(fromVpnAddrs[0], detailsVpnAddr, n.Details.V6AddrPorts, lhh.lh.unlockedShouldAddV6)
+	am.unlockedSetV6(fromVpnAddrs[0], fromVpnAddrs[0], n.Details.V6AddrPorts, lhh.lh.unlockedShouldAddV6)
 	am.unlockedSetRelay(fromVpnAddrs[0], relays)
 	am.Unlock()
 
 	n = lhh.resetMeta()
 	n.Type = NebulaMeta_HostUpdateNotificationAck
-
+	switch useVersion {
-	if useVersion == cert.Version1 {
+	case cert.Version1:
 		if !fromVpnAddrs[0].Is4() {
 			lhh.l.WithField("vpnAddrs", fromVpnAddrs).Error("Can not send HostUpdateNotificationAck for a ipv6 vpn ip in a v1 message")
 			return
 		}
 		vpnAddrB := fromVpnAddrs[0].As4()
 		n.Details.OldVpnAddr = binary.BigEndian.Uint32(vpnAddrB[:])
-	} else if useVersion == cert.Version2 {
+	case cert.Version2:
-		n.Details.VpnAddr = netAddrToProtoAddr(fromVpnAddrs[0])
+		// do nothing, we want to send a blank message
-	} else {
+	default:
 		lhh.l.WithField("useVersion", useVersion).Error("invalid protocol version")
 		return
 	}
@@ -1289,7 +1308,6 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 func (lhh *LightHouseHandler) handleHostPunchNotification(n *NebulaMeta, fromVpnAddrs []netip.Addr, w EncWriter) {
 	//It's possible the lighthouse is communicating with us using a non primary vpn addr,
 	//which means we need to compare all fromVpnAddrs against all configured lighthouse vpn addrs.
-	//maybe one day we'll have a better idea, if it matters.
 	if !lhh.lh.IsAnyLighthouseAddr(fromVpnAddrs) {
 		return
 	}
@@ -1407,7 +1425,7 @@ func (d *NebulaMetaDetails) GetRelays() []netip.Addr {
 	return relays
 }
 
-// FindNetworkUnion returns the first netip.Addr contained in the list of provided netip.Prefix, if able
+// findNetworkUnion returns the first netip.Addr of addrs contained in the list of provided netip.Prefix, if able
 func findNetworkUnion(prefixes []netip.Prefix, addrs []netip.Addr) (netip.Addr, bool) {
 	for i := range prefixes {
 		for j := range addrs {
@@ -1432,3 +1450,13 @@ func (d *NebulaMetaDetails) GetVpnAddrAndVersion() (netip.Addr, cert.Version, er
 		return netip.Addr{}, cert.Version1, ErrBadDetailsVpnAddr
 	}
 }
+
+func (d *NebulaControl) GetRelayFrom() netip.Addr {
+	if d.OldRelayFromAddr != 0 {
+		b := [4]byte{}
+		binary.BigEndian.PutUint32(b[:], d.OldRelayFromAddr)
+		return netip.AddrFrom4(b)
+	} else {
+		return protoAddrToNetAddr(d.RelayFromAddr)
+	}
+}

overlay/tun.go

@@ -1,6 +1,8 @@
 package overlay
 
 import (
+	"fmt"
+	"net"
 	"net/netip"
 
 	"github.com/sirupsen/logrus"
@@ -70,3 +72,51 @@ func findRemovedRoutes(newRoutes, oldRoutes []Route) []Route {
 
 	return removed
 }
+
+func prefixToMask(prefix netip.Prefix) netip.Addr {
+	pLen := 128
+	if prefix.Addr().Is4() {
+		pLen = 32
+	}
+
+	addr, _ := netip.AddrFromSlice(net.CIDRMask(prefix.Bits(), pLen))
+	return addr
+}
+
+func flipBytes(b []byte) []byte {
+	for i := 0; i < len(b); i++ {
+		b[i] ^= 0xFF
+	}
+	return b
+}
+func orBytes(a []byte, b []byte) []byte {
+	ret := make([]byte, len(a))
+	for i := 0; i < len(a); i++ {
+		ret[i] = a[i] | b[i]
+	}
+	return ret
+}
+
+func getBroadcast(cidr netip.Prefix) netip.Addr {
+	broadcast, _ := netip.AddrFromSlice(
+		orBytes(
+			cidr.Addr().AsSlice(),
+			flipBytes(prefixToMask(cidr).AsSlice()),
+		),
+	)
+	return broadcast
+}
+
+func selectGateway(dest netip.Prefix, gateways []netip.Prefix) (netip.Prefix, error) {
+	for _, gateway := range gateways {
+		if dest.Addr().Is4() && gateway.Addr().Is4() {
+			return gateway, nil
+		}
+
+		if dest.Addr().Is6() && gateway.Addr().Is6() {
+			return gateway, nil
+		}
+	}
+
+	return netip.Prefix{}, fmt.Errorf("no gateway found for %v in the list of vpn networks", dest)
+}

overlay/tun_darwin.go

@@ -7,7 +7,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"net"
 	"net/netip"
 	"os"
 	"sync/atomic"
@@ -295,7 +294,6 @@ func (t *tun) activate6(network netip.Prefix) error {
 			Vltime: 0xffffffff,
 			Pltime: 0xffffffff,
 		},
-		//TODO: CERT-V2 should we disable DAD (duplicate address detection) and mark this as a secured address?
 		Flags: _IN6_IFF_NODAD,
 	}
 
@@ -554,13 +552,3 @@ func (t *tun) Name() string {
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for darwin")
 }
-
-func prefixToMask(prefix netip.Prefix) netip.Addr {
-	pLen := 128
-	if prefix.Addr().Is4() {
-		pLen = 32
-	}
-
-	addr, _ := netip.AddrFromSlice(net.CIDRMask(prefix.Bits(), pLen))
-	return addr
-}

overlay/tun_freebsd.go

@@ -10,11 +10,9 @@ import (
 	"io"
 	"io/fs"
 	"net/netip"
-	"os"
-	"os/exec"
-	"strconv"
 	"sync/atomic"
 	"syscall"
+	"time"
 	"unsafe"
 
 	"github.com/gaissmai/bart"
@@ -22,12 +20,18 @@ import (
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	netroute "golang.org/x/net/route"
+	"golang.org/x/sys/unix"
 )
 
 const (
 	// FIODGNAME is defined in sys/sys/filio.h on FreeBSD
 	// For 32-bit systems, use FIODGNAME_32 (not defined in this file: 0x80086678)
-	FIODGNAME = 0x80106678
+	FIODGNAME        = 0x80106678
+	TUNSIFMODE       = 0x8004745e
+	TUNSIFHEAD       = 0x80047460
+	OSIOCAIFADDR_IN6 = 0x8088691b
+	IN6_IFF_NODAD    = 0x0020
 )
 
 type fiodgnameArg struct {
@@ -37,43 +41,159 @@ type fiodgnameArg struct {
 }
 
 type ifreqRename struct {
-	Name [16]byte
+	Name [unix.IFNAMSIZ]byte
 	Data uintptr
 }
 
 type ifreqDestroy struct {
-	Name [16]byte
+	Name [unix.IFNAMSIZ]byte
 	pad  [16]byte
 }
 
+type ifReq struct {
+	Name  [unix.IFNAMSIZ]byte
+	Flags uint16
+}
+
+type ifreqMTU struct {
+	Name [unix.IFNAMSIZ]byte
+	MTU  int32
+}
+
+type addrLifetime struct {
+	Expire    uint64
+	Preferred uint64
+	Vltime    uint32
+	Pltime    uint32
+}
+
+type ifreqAlias4 struct {
+	Name     [unix.IFNAMSIZ]byte
+	Addr     unix.RawSockaddrInet4
+	DstAddr  unix.RawSockaddrInet4
+	MaskAddr unix.RawSockaddrInet4
+	VHid     uint32
+}
+
+type ifreqAlias6 struct {
+	Name       [unix.IFNAMSIZ]byte
+	Addr       unix.RawSockaddrInet6
+	DstAddr    unix.RawSockaddrInet6
+	PrefixMask unix.RawSockaddrInet6
+	Flags      uint32
+	Lifetime   addrLifetime
+	VHid       uint32
+}
+
 type tun struct {
 	Device      string
 	vpnNetworks []netip.Prefix
 	MTU         int
 	Routes      atomic.Pointer[[]Route]
 	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
+	linkAddr    *netroute.LinkAddr
 	l           *logrus.Logger
+	devFd       int
+}
 
-	io.ReadWriteCloser
+func (t *tun) Read(to []byte) (int, error) {
+	// use readv() to read from the tunnel device, to eliminate the need for copying the buffer
+	if t.devFd < 0 {
+		return -1, syscall.EINVAL
+	}
+
+	// first 4 bytes is protocol family, in network byte order
+	head := make([]byte, 4)
+
+	iovecs := []syscall.Iovec{
+		{&head[0], 4},
+		{&to[0], uint64(len(to))},
+	}
+
+	n, _, errno := syscall.Syscall(syscall.SYS_READV, uintptr(t.devFd), uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
+
+	var err error
+	if errno != 0 {
+		err = syscall.Errno(errno)
+	} else {
+		err = nil
+	}
+	// fix bytes read number to exclude header
+	bytesRead := int(n)
+	if bytesRead < 0 {
+		return bytesRead, err
+	} else if bytesRead < 4 {
+		return 0, err
+	} else {
+		return bytesRead - 4, err
+	}
+}
+
+// Write is only valid for single threaded use
+func (t *tun) Write(from []byte) (int, error) {
+	// use writev() to write to the tunnel device, to eliminate the need for copying the buffer
+	if t.devFd < 0 {
+		return -1, syscall.EINVAL
+	}
+
+	if len(from) <= 1 {
+		return 0, syscall.EIO
+	}
+	ipVer := from[0] >> 4
+	var head []byte
+	// first 4 bytes is protocol family, in network byte order
+	if ipVer == 4 {
+		head = []byte{0, 0, 0, syscall.AF_INET}
+	} else if ipVer == 6 {
+		head = []byte{0, 0, 0, syscall.AF_INET6}
+	} else {
+		return 0, fmt.Errorf("unable to determine IP version from packet")
+	}
+	iovecs := []syscall.Iovec{
+		{&head[0], 4},
+		{&from[0], uint64(len(from))},
+	}
+
+	n, _, errno := syscall.Syscall(syscall.SYS_WRITEV, uintptr(t.devFd), uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
+
+	var err error
+	if errno != 0 {
+		err = syscall.Errno(errno)
+	} else {
+		err = nil
+	}
+
+	return int(n) - 4, err
 }
 
 func (t *tun) Close() error {
-	if t.ReadWriteCloser != nil {
+	if t.devFd >= 0 {
-		if err := t.ReadWriteCloser.Close(); err != nil {
+		err := syscall.Close(t.devFd)
-			return err
-		}
-
-		s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
 		if err != nil {
-			return err
+			t.l.WithError(err).Error("Error closing device")
 		}
-		defer syscall.Close(s)
+		t.devFd = -1
 
-		ifreq := ifreqDestroy{Name: t.deviceBytes()}
+		c := make(chan struct{})
+		go func() {
+			// destroying the interface can block if a read() is still pending. Do this asynchronously.
+			defer close(c)
+			s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
+			if err == nil {
+				defer syscall.Close(s)
+				ifreq := ifreqDestroy{Name: t.deviceBytes()}
+				err = ioctl(uintptr(s), syscall.SIOCIFDESTROY, uintptr(unsafe.Pointer(&ifreq)))
+			}
+			if err != nil {
+				t.l.WithError(err).Error("Error destroying tunnel")
+			}
+		}()
 
-		// Destroy the interface
+		// wait up to 1 second so we start blocking at the ioctl
-		err = ioctl(uintptr(s), syscall.SIOCIFDESTROY, uintptr(unsafe.Pointer(&ifreq)))
+		select {
-		return err
+		case <-c:
+		case <-time.After(1 * time.Second):
+		}
 	}
 
 	return nil
@@ -85,32 +205,37 @@ func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun,
 
 func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*tun, error) {
 	// Try to open existing tun device
-	var file *os.File
+	var fd int
 	var err error
 	deviceName := c.GetString("tun.dev", "")
 	if deviceName != "" {
-		file, err = os.OpenFile("/dev/"+deviceName, os.O_RDWR, 0)
+		fd, err = syscall.Open("/dev/"+deviceName, syscall.O_RDWR, 0)
 	}
 	if errors.Is(err, fs.ErrNotExist) || deviceName == "" {
 		// If the device doesn't already exist, request a new one and rename it
-		file, err = os.OpenFile("/dev/tun", os.O_RDWR, 0)
+		fd, err = syscall.Open("/dev/tun", syscall.O_RDWR, 0)
 	}
 	if err != nil {
 		return nil, err
 	}
 
-	rawConn, err := file.SyscallConn()
+	// Read the name of the interface
-	if err != nil {
+	var name [16]byte
-		return nil, fmt.Errorf("SyscallConn: %v", err)
+	arg := fiodgnameArg{length: 16, buf: unsafe.Pointer(&name)}
+	ctrlErr := ioctl(uintptr(fd), FIODGNAME, uintptr(unsafe.Pointer(&arg)))
+
+	if ctrlErr == nil {
+		// set broadcast mode and multicast
+		ifmode := uint32(unix.IFF_BROADCAST | unix.IFF_MULTICAST)
+		ctrlErr = ioctl(uintptr(fd), TUNSIFMODE, uintptr(unsafe.Pointer(&ifmode)))
+	}
+
+	if ctrlErr == nil {
+		// turn on link-layer mode, to support ipv6
+		ifhead := uint32(1)
+		ctrlErr = ioctl(uintptr(fd), TUNSIFHEAD, uintptr(unsafe.Pointer(&ifhead)))
 	}
 
-	var name [16]byte
-	var ctrlErr error
-	rawConn.Control(func(fd uintptr) {
-		// Read the name of the interface
-		arg := fiodgnameArg{length: 16, buf: unsafe.Pointer(&name)}
-		ctrlErr = ioctl(fd, FIODGNAME, uintptr(unsafe.Pointer(&arg)))
-	})
 	if ctrlErr != nil {
 		return nil, err
 	}
@@ -122,11 +247,7 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 
 	// If the name doesn't match the desired interface name, rename it now
 	if ifName != deviceName {
-		s, err := syscall.Socket(
+		s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
-			syscall.AF_INET,
-			syscall.SOCK_DGRAM,
-			syscall.IPPROTO_IP,
-		)
 		if err != nil {
 			return nil, err
 		}
@@ -149,11 +270,11 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 	}
 
 	t := &tun{
-		ReadWriteCloser: file,
+		Device:      deviceName,
-		Device:          deviceName,
+		vpnNetworks: vpnNetworks,
-		vpnNetworks:     vpnNetworks,
+		MTU:         c.GetInt("tun.mtu", DefaultMTU),
-		MTU:             c.GetInt("tun.mtu", DefaultMTU),
+		l:           l,
-		l:               l,
+		devFd:       fd,
 	}
 
 	err = t.reload(c, true)
@@ -172,38 +293,111 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 }
 
 func (t *tun) addIp(cidr netip.Prefix) error {
-	var err error
+	if cidr.Addr().Is4() {
-	// TODO use syscalls instead of exec.Command
+		ifr := ifreqAlias4{
-	cmd := exec.Command("/sbin/ifconfig", t.Device, cidr.String(), cidr.Addr().String())
+			Name: t.deviceBytes(),
-	t.l.Debug("command: ", cmd.String())
+			Addr: unix.RawSockaddrInet4{
-	if err = cmd.Run(); err != nil {
+				Len:    unix.SizeofSockaddrInet4,
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
+				Family: unix.AF_INET,
+				Addr:   cidr.Addr().As4(),
+			},
+			DstAddr: unix.RawSockaddrInet4{
+				Len:    unix.SizeofSockaddrInet4,
+				Family: unix.AF_INET,
+				Addr:   getBroadcast(cidr).As4(),
+			},
+			MaskAddr: unix.RawSockaddrInet4{
+				Len:    unix.SizeofSockaddrInet4,
+				Family: unix.AF_INET,
+				Addr:   prefixToMask(cidr).As4(),
+			},
+			VHid: 0,
+		}
+		s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+		// Note: unix.SIOCAIFADDR corresponds to FreeBSD's OSIOCAIFADDR
+		if err := ioctl(uintptr(s), unix.SIOCAIFADDR, uintptr(unsafe.Pointer(&ifr))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr().String(), err)
+		}
+		return nil
 	}
 
-	cmd = exec.Command("/sbin/route", "-n", "add", "-net", cidr.String(), "-interface", t.Device)
+	if cidr.Addr().Is6() {
-	t.l.Debug("command: ", cmd.String())
+		ifr := ifreqAlias6{
-	if err = cmd.Run(); err != nil {
+			Name: t.deviceBytes(),
-		return fmt.Errorf("failed to run 'route add': %s", err)
+			Addr: unix.RawSockaddrInet6{
+				Len:    unix.SizeofSockaddrInet6,
+				Family: unix.AF_INET6,
+				Addr:   cidr.Addr().As16(),
+			},
+			PrefixMask: unix.RawSockaddrInet6{
+				Len:    unix.SizeofSockaddrInet6,
+				Family: unix.AF_INET6,
+				Addr:   prefixToMask(cidr).As16(),
+			},
+			Lifetime: addrLifetime{
+				Expire:    0,
+				Preferred: 0,
+				Vltime:    0xffffffff,
+				Pltime:    0xffffffff,
+			},
+			Flags: IN6_IFF_NODAD,
+		}
+		s, err := syscall.Socket(syscall.AF_INET6, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), OSIOCAIFADDR_IN6, uintptr(unsafe.Pointer(&ifr))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr().String(), err)
+		}
+		return nil
 	}
 
-	cmd = exec.Command("/sbin/ifconfig", t.Device, "mtu", strconv.Itoa(t.MTU))
+	return fmt.Errorf("unknown address type %v", cidr)
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
-	}
-
-	// Unsafe path routes
-	return t.addRoutes(false)
 }
 
 func (t *tun) Activate() error {
+	// Setup our default MTU
+	err := t.setMTU()
+	if err != nil {
+		return err
+	}
+
+	linkAddr, err := getLinkAddr(t.Device)
+	if err != nil {
+		return err
+	}
+	if linkAddr == nil {
+		return fmt.Errorf("unable to discover link_addr for tun interface")
+	}
+	t.linkAddr = linkAddr
+
 	for i := range t.vpnNetworks {
 		err := t.addIp(t.vpnNetworks[i])
 		if err != nil {
 			return err
 		}
 	}
-	return nil
+
+	return t.addRoutes(false)
+}
+
+func (t *tun) setMTU() error {
+	// Set the MTU on the device
+	s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(s)
+
+	ifm := ifreqMTU{Name: t.deviceBytes(), MTU: int32(t.MTU)}
+	err = ioctl(uintptr(s), unix.SIOCSIFMTU, uintptr(unsafe.Pointer(&ifm)))
+	return err
 }
 
 func (t *tun) reload(c *config.C, initial bool) error {
@@ -268,15 +462,16 @@ func (t *tun) addRoutes(logErrors bool) error {
 			continue
 		}
 
-		cmd := exec.Command("/sbin/route", "-n", "add", "-net", r.Cidr.String(), "-interface", t.Device)
+		err := addRoute(r.Cidr, t.linkAddr)
-		t.l.Debug("command: ", cmd.String())
+		if err != nil {
-		if err := cmd.Run(); err != nil {
+			retErr := util.NewContextualError("Failed to add route", map[string]any{"route": r}, err)
-			retErr := util.NewContextualError("failed to run 'route add' for unsafe_route", map[string]any{"route": r}, err)
 			if logErrors {
 				retErr.Log(t.l)
 			} else {
 				return retErr
 			}
+		} else {
+			t.l.WithField("route", r).Info("Added route")
 		}
 	}
 
@@ -289,9 +484,8 @@ func (t *tun) removeRoutes(routes []Route) error {
 			continue
 		}
 
-		cmd := exec.Command("/sbin/route", "-n", "delete", "-net", r.Cidr.String(), "-interface", t.Device)
+		err := delRoute(r.Cidr, t.linkAddr)
-		t.l.Debug("command: ", cmd.String())
+		if err != nil {
-		if err := cmd.Run(); err != nil {
 			t.l.WithError(err).WithField("route", r).Error("Failed to remove route")
 		} else {
 			t.l.WithField("route", r).Info("Removed route")
@@ -306,3 +500,120 @@ func (t *tun) deviceBytes() (o [16]byte) {
 	}
 	return
 }
+
+func addRoute(prefix netip.Prefix, gateway netroute.Addr) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := &netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_ADD,
+		Flags:   unix.RTF_UP,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: gateway,
+		}
+	} else {
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: gateway,
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		if errors.Is(err, unix.EEXIST) {
+			// Try to do a change
+			route.Type = unix.RTM_CHANGE
+			data, err = route.Marshal()
+			if err != nil {
+				return fmt.Errorf("failed to create route.RouteMessage for change: %w", err)
+			}
+			_, err = unix.Write(sock, data[:])
+			fmt.Println("DOING CHANGE")
+			return err
+		}
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}
+
+func delRoute(prefix netip.Prefix, gateway netroute.Addr) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_DELETE,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: gateway,
+		}
+	} else {
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: gateway,
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}
+
+// getLinkAddr Gets the link address for the interface of the given name
+func getLinkAddr(name string) (*netroute.LinkAddr, error) {
+	rib, err := netroute.FetchRIB(unix.AF_UNSPEC, unix.NET_RT_IFLIST, 0)
+	if err != nil {
+		return nil, err
+	}
+	msgs, err := netroute.ParseRIB(unix.NET_RT_IFLIST, rib)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, m := range msgs {
+		switch m := m.(type) {
+		case *netroute.InterfaceMessage:
+			if m.Name == name {
+				sa, ok := m.Addrs[unix.RTAX_IFP].(*netroute.LinkAddr)
+				if ok {
+					return sa, nil
+				}
+			}
+		}
+	}
+
+	return nil, nil
+}

overlay/tun_netbsd.go

@@ -4,13 +4,12 @@
 package overlay
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"net/netip"
 	"os"
-	"os/exec"
 	"regexp"
-	"strconv"
 	"sync/atomic"
 	"syscall"
 	"unsafe"
@@ -20,11 +19,42 @@ import (
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	netroute "golang.org/x/net/route"
+	"golang.org/x/sys/unix"
 )
 
-type ifreqDestroy struct {
+const (
-	Name [16]byte
+	SIOCAIFADDR_IN6 = 0x8080696b
-	pad  [16]byte
+	TUNSIFHEAD      = 0x80047442
+	TUNSIFMODE      = 0x80047458
+)
+
+type ifreqAlias4 struct {
+	Name     [unix.IFNAMSIZ]byte
+	Addr     unix.RawSockaddrInet4
+	DstAddr  unix.RawSockaddrInet4
+	MaskAddr unix.RawSockaddrInet4
+}
+
+type ifreqAlias6 struct {
+	Name       [unix.IFNAMSIZ]byte
+	Addr       unix.RawSockaddrInet6
+	DstAddr    unix.RawSockaddrInet6
+	PrefixMask unix.RawSockaddrInet6
+	Flags      uint32
+	Lifetime   addrLifetime
+}
+
+type ifreq struct {
+	Name [unix.IFNAMSIZ]byte
+	data int
+}
+
+type addrLifetime struct {
+	Expire    uint64
+	Preferred uint64
+	Vltime    uint32
+	Pltime    uint32
 }
 
 type tun struct {
@@ -34,40 +64,18 @@ type tun struct {
 	Routes      atomic.Pointer[[]Route]
 	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
 	l           *logrus.Logger
-
+	f           *os.File
-	io.ReadWriteCloser
+	fd          int
 }
 
-func (t *tun) Close() error {
+var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
-	if t.ReadWriteCloser != nil {
-		if err := t.ReadWriteCloser.Close(); err != nil {
-			return err
-		}
-
-		s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
-		if err != nil {
-			return err
-		}
-		defer syscall.Close(s)
-
-		ifreq := ifreqDestroy{Name: t.deviceBytes()}
-
-		err = ioctl(uintptr(s), syscall.SIOCIFDESTROY, uintptr(unsafe.Pointer(&ifreq)))
-
-		return err
-	}
-	return nil
-}
 
 func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in NetBSD")
 }
 
-var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
-
 func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*tun, error) {
 	// Try to open tun device
-	var file *os.File
 	var err error
 	deviceName := c.GetString("tun.dev", "")
 	if deviceName == "" {
@@ -77,17 +85,23 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 		return nil, fmt.Errorf("a device name in the format of /dev/tunN must be specified")
 	}
 
-	file, err = os.OpenFile("/dev/"+deviceName, os.O_RDWR, 0)
+	fd, err := unix.Open("/dev/"+deviceName, os.O_RDWR, 0)
 	if err != nil {
 		return nil, err
 	}
 
+	err = unix.SetNonblock(fd, true)
+	if err != nil {
+		l.WithError(err).Warn("Failed to set the tun device as nonblocking")
+	}
+
 	t := &tun{
-		ReadWriteCloser: file,
+		f:           os.NewFile(uintptr(fd), ""),
-		Device:          deviceName,
+		fd:          fd,
-		vpnNetworks:     vpnNetworks,
+		Device:      deviceName,
-		MTU:             c.GetInt("tun.mtu", DefaultMTU),
+		vpnNetworks: vpnNetworks,
-		l:               l,
+		MTU:         c.GetInt("tun.mtu", DefaultMTU),
+		l:           l,
 	}
 
 	err = t.reload(c, true)
@@ -105,40 +119,225 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 	return t, nil
 }
 
+func (t *tun) Close() error {
+	if t.f != nil {
+		if err := t.f.Close(); err != nil {
+			return fmt.Errorf("error closing tun file: %w", err)
+		}
+
+		// t.f.Close should have handled it for us but let's be extra sure
+		_ = unix.Close(t.fd)
+
+		s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		ifr := ifreq{Name: t.deviceBytes()}
+		err = ioctl(uintptr(s), syscall.SIOCIFDESTROY, uintptr(unsafe.Pointer(&ifr)))
+		return err
+	}
+	return nil
+}
+
+func (t *tun) Read(to []byte) (int, error) {
+	rc, err := t.f.SyscallConn()
+	if err != nil {
+		return 0, fmt.Errorf("failed to get syscall conn for tun: %w", err)
+	}
+
+	var errno syscall.Errno
+	var n uintptr
+	err = rc.Read(func(fd uintptr) bool {
+		// first 4 bytes is protocol family, in network byte order
+		head := [4]byte{}
+		iovecs := []syscall.Iovec{
+			{&head[0], 4},
+			{&to[0], uint64(len(to))},
+		}
+
+		n, _, errno = syscall.Syscall(syscall.SYS_READV, fd, uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
+		if errno.Temporary() {
+			// We got an EAGAIN, EINTR, or EWOULDBLOCK, go again
+			return false
+		}
+		return true
+	})
+	if err != nil {
+		if err == syscall.EBADF || err.Error() == "use of closed file" {
+			// Go doesn't export poll.ErrFileClosing but happily reports it to us so here we are
+			// https://github.com/golang/go/blob/master/src/internal/poll/fd_poll_runtime.go#L121
+			return 0, os.ErrClosed
+		}
+		return 0, fmt.Errorf("failed to make read call for tun: %w", err)
+	}
+
+	if errno != 0 {
+		return 0, fmt.Errorf("failed to make inner read call for tun: %w", errno)
+	}
+
+	// fix bytes read number to exclude header
+	bytesRead := int(n)
+	if bytesRead < 0 {
+		return bytesRead, nil
+	} else if bytesRead < 4 {
+		return 0, nil
+	} else {
+		return bytesRead - 4, nil
+	}
+}
+
+// Write is only valid for single threaded use
+func (t *tun) Write(from []byte) (int, error) {
+	if len(from) <= 1 {
+		return 0, syscall.EIO
+	}
+
+	ipVer := from[0] >> 4
+	var head [4]byte
+	// first 4 bytes is protocol family, in network byte order
+	if ipVer == 4 {
+		head[3] = syscall.AF_INET
+	} else if ipVer == 6 {
+		head[3] = syscall.AF_INET6
+	} else {
+		return 0, fmt.Errorf("unable to determine IP version from packet")
+	}
+
+	rc, err := t.f.SyscallConn()
+	if err != nil {
+		return 0, err
+	}
+
+	var errno syscall.Errno
+	var n uintptr
+	err = rc.Write(func(fd uintptr) bool {
+		iovecs := []syscall.Iovec{
+			{&head[0], 4},
+			{&from[0], uint64(len(from))},
+		}
+
+		n, _, errno = syscall.Syscall(syscall.SYS_WRITEV, fd, uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
+		// According to NetBSD documentation for TUN, writes will only return errors in which
+		// this packet will never be delivered so just go on living life.
+		return true
+	})
+	if err != nil {
+		return 0, err
+	}
+
+	if errno != 0 {
+		return 0, errno
+	}
+
+	return int(n) - 4, err
+}
+
 func (t *tun) addIp(cidr netip.Prefix) error {
-	var err error
+	if cidr.Addr().Is4() {
+		var req ifreqAlias4
+		req.Name = t.deviceBytes()
+		req.Addr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   cidr.Addr().As4(),
+		}
+		req.DstAddr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   cidr.Addr().As4(),
+		}
+		req.MaskAddr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   prefixToMask(cidr).As4(),
+		}
 
-	// TODO use syscalls instead of exec.Command
+		s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
-	cmd := exec.Command("/sbin/ifconfig", t.Device, cidr.String(), cidr.Addr().String())
+		if err != nil {
-	t.l.Debug("command: ", cmd.String())
+			return err
-	if err = cmd.Run(); err != nil {
+		}
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), unix.SIOCAIFADDR, uintptr(unsafe.Pointer(&req))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr(), err)
+		}
+
+		return nil
 	}
 
-	cmd = exec.Command("/sbin/route", "-n", "add", "-net", cidr.String(), cidr.Addr().String())
+	if cidr.Addr().Is6() {
-	t.l.Debug("command: ", cmd.String())
+		var req ifreqAlias6
-	if err = cmd.Run(); err != nil {
+		req.Name = t.deviceBytes()
-		return fmt.Errorf("failed to run 'route add': %s", err)
+		req.Addr = unix.RawSockaddrInet6{
+			Len:    unix.SizeofSockaddrInet6,
+			Family: unix.AF_INET6,
+			Addr:   cidr.Addr().As16(),
+		}
+		req.PrefixMask = unix.RawSockaddrInet6{
+			Len:    unix.SizeofSockaddrInet6,
+			Family: unix.AF_INET6,
+			Addr:   prefixToMask(cidr).As16(),
+		}
+		req.Lifetime = addrLifetime{
+			Vltime: 0xffffffff,
+			Pltime: 0xffffffff,
+		}
+
+		s, err := unix.Socket(unix.AF_INET6, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), SIOCAIFADDR_IN6, uintptr(unsafe.Pointer(&req))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr().String(), err)
+		}
+		return nil
 	}
 
-	cmd = exec.Command("/sbin/ifconfig", t.Device, "mtu", strconv.Itoa(t.MTU))
+	return fmt.Errorf("unknown address type %v", cidr)
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
-	}
-
-	// Unsafe path routes
-	return t.addRoutes(false)
 }
 
 func (t *tun) Activate() error {
+	mode := int32(unix.IFF_BROADCAST)
+	err := ioctl(uintptr(t.fd), TUNSIFMODE, uintptr(unsafe.Pointer(&mode)))
+	if err != nil {
+		return fmt.Errorf("failed to set tun device mode: %w", err)
+	}
+
+	v := 1
+	err = ioctl(uintptr(t.fd), TUNSIFHEAD, uintptr(unsafe.Pointer(&v)))
+	if err != nil {
+		return fmt.Errorf("failed to set tun device head: %w", err)
+	}
+
+	err = t.doIoctlByName(unix.SIOCSIFMTU, uint32(t.MTU))
+	if err != nil {
+		return fmt.Errorf("failed to set tun mtu: %w", err)
+	}
+
 	for i := range t.vpnNetworks {
-		err := t.addIp(t.vpnNetworks[i])
+		err = t.addIp(t.vpnNetworks[i])
 		if err != nil {
 			return err
 		}
 	}
-	return nil
+
+	return t.addRoutes(false)
+}
+
+func (t *tun) doIoctlByName(ctl uintptr, value uint32) error {
+	s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(s)
+
+	ir := ifreq{Name: t.deviceBytes(), data: int(value)}
+	err = ioctl(uintptr(s), ctl, uintptr(unsafe.Pointer(&ir)))
+	return err
 }
 
 func (t *tun) reload(c *config.C, initial bool) error {
@@ -197,21 +396,23 @@ func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 
 func (t *tun) addRoutes(logErrors bool) error {
 	routes := *t.Routes.Load()
+
 	for _, r := range routes {
 		if len(r.Via) == 0 || !r.Install {
 			// We don't allow route MTUs so only install routes with a via
 			continue
 		}
 
-		cmd := exec.Command("/sbin/route", "-n", "add", "-net", r.Cidr.String(), t.vpnNetworks[0].Addr().String())
+		err := addRoute(r.Cidr, t.vpnNetworks)
-		t.l.Debug("command: ", cmd.String())
+		if err != nil {
-		if err := cmd.Run(); err != nil {
+			retErr := util.NewContextualError("Failed to add route", map[string]any{"route": r}, err)
-			retErr := util.NewContextualError("failed to run 'route add' for unsafe_route", map[string]any{"route": r}, err)
 			if logErrors {
 				retErr.Log(t.l)
 			} else {
 				return retErr
 			}
+		} else {
+			t.l.WithField("route", r).Info("Added route")
 		}
 	}
 
@@ -224,10 +425,8 @@ func (t *tun) removeRoutes(routes []Route) error {
 			continue
 		}
 
-		//TODO: CERT-V2 is this right?
+		err := delRoute(r.Cidr, t.vpnNetworks)
-		cmd := exec.Command("/sbin/route", "-n", "delete", "-net", r.Cidr.String(), t.vpnNetworks[0].Addr().String())
+		if err != nil {
-		t.l.Debug("command: ", cmd.String())
-		if err := cmd.Run(); err != nil {
 			t.l.WithError(err).WithField("route", r).Error("Failed to remove route")
 		} else {
 			t.l.WithField("route", r).Info("Removed route")
@@ -242,3 +441,109 @@ func (t *tun) deviceBytes() (o [16]byte) {
 	}
 	return
 }
+
+func addRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := &netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_ADD,
+		Flags:   unix.RTF_UP | unix.RTF_GATEWAY,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: &netroute.Inet4Addr{IP: gw.Addr().As4()},
+		}
+	} else {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: &netroute.Inet6Addr{IP: gw.Addr().As16()},
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		if errors.Is(err, unix.EEXIST) {
+			// Try to do a change
+			route.Type = unix.RTM_CHANGE
+			data, err = route.Marshal()
+			if err != nil {
+				return fmt.Errorf("failed to create route.RouteMessage for change: %w", err)
+			}
+			_, err = unix.Write(sock, data[:])
+			return err
+		}
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}
+
+func delRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_DELETE,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: &netroute.Inet4Addr{IP: gw.Addr().As4()},
+		}
+	} else {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: &netroute.Inet6Addr{IP: gw.Addr().As16()},
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}

overlay/tun_openbsd.go

@@ -4,23 +4,50 @@
 package overlay
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"net/netip"
 	"os"
-	"os/exec"
 	"regexp"
-	"strconv"
 	"sync/atomic"
 	"syscall"
+	"unsafe"
 
 	"github.com/gaissmai/bart"
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	netroute "golang.org/x/net/route"
+	"golang.org/x/sys/unix"
 )
 
+const (
+	SIOCAIFADDR_IN6 = 0x8080691a
+)
+
+type ifreqAlias4 struct {
+	Name     [unix.IFNAMSIZ]byte
+	Addr     unix.RawSockaddrInet4
+	DstAddr  unix.RawSockaddrInet4
+	MaskAddr unix.RawSockaddrInet4
+}
+
+type ifreqAlias6 struct {
+	Name       [unix.IFNAMSIZ]byte
+	Addr       unix.RawSockaddrInet6
+	DstAddr    unix.RawSockaddrInet6
+	PrefixMask unix.RawSockaddrInet6
+	Flags      uint32
+	Lifetime   [2]uint32
+}
+
+type ifreq struct {
+	Name [unix.IFNAMSIZ]byte
+	data int
+}
+
 type tun struct {
 	Device      string
 	vpnNetworks []netip.Prefix
@@ -28,48 +55,46 @@ type tun struct {
 	Routes      atomic.Pointer[[]Route]
 	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
 	l           *logrus.Logger
-
+	f           *os.File
-	io.ReadWriteCloser
+	fd          int
-
 	// cache out buffer since we need to prepend 4 bytes for tun metadata
 	out []byte
 }
 
-func (t *tun) Close() error {
-	if t.ReadWriteCloser != nil {
-		return t.ReadWriteCloser.Close()
-	}
-
-	return nil
-}
-
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
-	return nil, fmt.Errorf("newTunFromFd not supported in OpenBSD")
-}
-
 var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
 
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
+	return nil, fmt.Errorf("newTunFromFd not supported in openbsd")
+}
+
 func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*tun, error) {
+	// Try to open tun device
+	var err error
 	deviceName := c.GetString("tun.dev", "")
 	if deviceName == "" {
-		return nil, fmt.Errorf("a device name in the format of tunN must be specified")
+		return nil, fmt.Errorf("a device name in the format of /dev/tunN must be specified")
 	}
-
 	if !deviceNameRE.MatchString(deviceName) {
-		return nil, fmt.Errorf("a device name in the format of tunN must be specified")
+		return nil, fmt.Errorf("a device name in the format of /dev/tunN must be specified")
 	}
 
-	file, err := os.OpenFile("/dev/"+deviceName, os.O_RDWR, 0)
+	fd, err := unix.Open("/dev/"+deviceName, os.O_RDWR, 0)
 	if err != nil {
 		return nil, err
 	}
 
+	err = unix.SetNonblock(fd, true)
+	if err != nil {
+		l.WithError(err).Warn("Failed to set the tun device as nonblocking")
+	}
+
 	t := &tun{
-		ReadWriteCloser: file,
+		f:           os.NewFile(uintptr(fd), ""),
-		Device:          deviceName,
+		fd:          fd,
-		vpnNetworks:     vpnNetworks,
+		Device:      deviceName,
-		MTU:             c.GetInt("tun.mtu", DefaultMTU),
+		vpnNetworks: vpnNetworks,
-		l:               l,
+		MTU:         c.GetInt("tun.mtu", DefaultMTU),
+		l:           l,
 	}
 
 	err = t.reload(c, true)
@@ -87,6 +112,154 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 	return t, nil
 }
 
+func (t *tun) Close() error {
+	if t.f != nil {
+		if err := t.f.Close(); err != nil {
+			return fmt.Errorf("error closing tun file: %w", err)
+		}
+
+		// t.f.Close should have handled it for us but let's be extra sure
+		_ = unix.Close(t.fd)
+	}
+	return nil
+}
+
+func (t *tun) Read(to []byte) (int, error) {
+	buf := make([]byte, len(to)+4)
+
+	n, err := t.f.Read(buf)
+
+	copy(to, buf[4:])
+	return n - 4, err
+}
+
+// Write is only valid for single threaded use
+func (t *tun) Write(from []byte) (int, error) {
+	buf := t.out
+	if cap(buf) < len(from)+4 {
+		buf = make([]byte, len(from)+4)
+		t.out = buf
+	}
+	buf = buf[:len(from)+4]
+
+	if len(from) == 0 {
+		return 0, syscall.EIO
+	}
+
+	// Determine the IP Family for the NULL L2 Header
+	ipVer := from[0] >> 4
+	if ipVer == 4 {
+		buf[3] = syscall.AF_INET
+	} else if ipVer == 6 {
+		buf[3] = syscall.AF_INET6
+	} else {
+		return 0, fmt.Errorf("unable to determine IP version from packet")
+	}
+
+	copy(buf[4:], from)
+
+	n, err := t.f.Write(buf)
+	return n - 4, err
+}
+
+func (t *tun) addIp(cidr netip.Prefix) error {
+	if cidr.Addr().Is4() {
+		var req ifreqAlias4
+		req.Name = t.deviceBytes()
+		req.Addr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   cidr.Addr().As4(),
+		}
+		req.DstAddr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   cidr.Addr().As4(),
+		}
+		req.MaskAddr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   prefixToMask(cidr).As4(),
+		}
+
+		s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), unix.SIOCAIFADDR, uintptr(unsafe.Pointer(&req))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr(), err)
+		}
+
+		err = addRoute(cidr, t.vpnNetworks)
+		if err != nil {
+			return fmt.Errorf("failed to set route for vpn network %v: %w", cidr, err)
+		}
+
+		return nil
+	}
+
+	if cidr.Addr().Is6() {
+		var req ifreqAlias6
+		req.Name = t.deviceBytes()
+		req.Addr = unix.RawSockaddrInet6{
+			Len:    unix.SizeofSockaddrInet6,
+			Family: unix.AF_INET6,
+			Addr:   cidr.Addr().As16(),
+		}
+		req.PrefixMask = unix.RawSockaddrInet6{
+			Len:    unix.SizeofSockaddrInet6,
+			Family: unix.AF_INET6,
+			Addr:   prefixToMask(cidr).As16(),
+		}
+		req.Lifetime[0] = 0xffffffff
+		req.Lifetime[1] = 0xffffffff
+
+		s, err := unix.Socket(unix.AF_INET6, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), SIOCAIFADDR_IN6, uintptr(unsafe.Pointer(&req))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr().String(), err)
+		}
+
+		return nil
+	}
+
+	return fmt.Errorf("unknown address type %v", cidr)
+}
+
+func (t *tun) Activate() error {
+	err := t.doIoctlByName(unix.SIOCSIFMTU, uint32(t.MTU))
+	if err != nil {
+		return fmt.Errorf("failed to set tun mtu: %w", err)
+	}
+
+	for i := range t.vpnNetworks {
+		err = t.addIp(t.vpnNetworks[i])
+		if err != nil {
+			return err
+		}
+	}
+
+	return t.addRoutes(false)
+}
+
+func (t *tun) doIoctlByName(ctl uintptr, value uint32) error {
+	s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(s)
+
+	ir := ifreq{Name: t.deviceBytes(), data: int(value)}
+	err = ioctl(uintptr(s), ctl, uintptr(unsafe.Pointer(&ir)))
+	return err
+}
+
 func (t *tun) reload(c *config.C, initial bool) error {
 	change, routes, err := getAllRoutesFromConfig(c, t.vpnNetworks, initial)
 	if err != nil {
@@ -124,86 +297,11 @@ func (t *tun) reload(c *config.C, initial bool) error {
 	return nil
 }
 
-func (t *tun) addIp(cidr netip.Prefix) error {
-	var err error
-	// TODO use syscalls instead of exec.Command
-	cmd := exec.Command("/sbin/ifconfig", t.Device, cidr.String(), cidr.Addr().String())
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
-	}
-
-	cmd = exec.Command("/sbin/ifconfig", t.Device, "mtu", strconv.Itoa(t.MTU))
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
-	}
-
-	cmd = exec.Command("/sbin/route", "-n", "add", "-inet", cidr.String(), cidr.Addr().String())
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'route add': %s", err)
-	}
-
-	// Unsafe path routes
-	return t.addRoutes(false)
-}
-
-func (t *tun) Activate() error {
-	for i := range t.vpnNetworks {
-		err := t.addIp(t.vpnNetworks[i])
-		if err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
 func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
 	r, _ := t.routeTree.Load().Lookup(ip)
 	return r
 }
 
-func (t *tun) addRoutes(logErrors bool) error {
-	routes := *t.Routes.Load()
-	for _, r := range routes {
-		if len(r.Via) == 0 || !r.Install {
-			// We don't allow route MTUs so only install routes with a via
-			continue
-		}
-		//TODO: CERT-V2 is this right?
-		cmd := exec.Command("/sbin/route", "-n", "add", "-inet", r.Cidr.String(), t.vpnNetworks[0].Addr().String())
-		t.l.Debug("command: ", cmd.String())
-		if err := cmd.Run(); err != nil {
-			retErr := util.NewContextualError("failed to run 'route add' for unsafe_route", map[string]any{"route": r}, err)
-			if logErrors {
-				retErr.Log(t.l)
-			} else {
-				return retErr
-			}
-		}
-	}
-
-	return nil
-}
-
-func (t *tun) removeRoutes(routes []Route) error {
-	for _, r := range routes {
-		if !r.Install {
-			continue
-		}
-		//TODO: CERT-V2 is this right?
-		cmd := exec.Command("/sbin/route", "-n", "delete", "-inet", r.Cidr.String(), t.vpnNetworks[0].Addr().String())
-		t.l.Debug("command: ", cmd.String())
-		if err := cmd.Run(); err != nil {
-			t.l.WithError(err).WithField("route", r).Error("Failed to remove route")
-		} else {
-			t.l.WithField("route", r).Info("Removed route")
-		}
-	}
-	return nil
-}
-
 func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
@@ -213,43 +311,159 @@ func (t *tun) Name() string {
 }
 
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
-	return nil, fmt.Errorf("TODO: multiqueue not implemented for freebsd")
+	return nil, fmt.Errorf("TODO: multiqueue not implemented for openbsd")
 }
 
-func (t *tun) Read(to []byte) (int, error) {
+func (t *tun) addRoutes(logErrors bool) error {
-	buf := make([]byte, len(to)+4)
+	routes := *t.Routes.Load()
 
-	n, err := t.ReadWriteCloser.Read(buf)
+	for _, r := range routes {
+		if len(r.Via) == 0 || !r.Install {
+			// We don't allow route MTUs so only install routes with a via
+			continue
+		}
 
-	copy(to, buf[4:])
+		err := addRoute(r.Cidr, t.vpnNetworks)
-	return n - 4, err
+		if err != nil {
+			retErr := util.NewContextualError("Failed to add route", map[string]any{"route": r}, err)
+			if logErrors {
+				retErr.Log(t.l)
+			} else {
+				return retErr
+			}
+		} else {
+			t.l.WithField("route", r).Info("Added route")
+		}
+	}
+
+	return nil
 }
 
-// Write is only valid for single threaded use
+func (t *tun) removeRoutes(routes []Route) error {
-func (t *tun) Write(from []byte) (int, error) {
+	for _, r := range routes {
-	buf := t.out
+		if !r.Install {
-	if cap(buf) < len(from)+4 {
+			continue
-		buf = make([]byte, len(from)+4)
+		}
-		t.out = buf
-	}
-	buf = buf[:len(from)+4]
 
-	if len(from) == 0 {
+		err := delRoute(r.Cidr, t.vpnNetworks)
-		return 0, syscall.EIO
+		if err != nil {
+			t.l.WithError(err).WithField("route", r).Error("Failed to remove route")
+		} else {
+			t.l.WithField("route", r).Info("Removed route")
+		}
+	}
+	return nil
+}
+
+func (t *tun) deviceBytes() (o [16]byte) {
+	for i, c := range t.Device {
+		o[i] = byte(c)
+	}
+	return
+}
+
+func addRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := &netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_ADD,
+		Flags:   unix.RTF_UP | unix.RTF_GATEWAY,
+		Seq:     1,
 	}
 
-	// Determine the IP Family for the NULL L2 Header
+	if prefix.Addr().Is4() {
-	ipVer := from[0] >> 4
+		gw, err := selectGateway(prefix, gateways)
-	if ipVer == 4 {
+		if err != nil {
-		buf[3] = syscall.AF_INET
+			return err
-	} else if ipVer == 6 {
+		}
-		buf[3] = syscall.AF_INET6
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: &netroute.Inet4Addr{IP: gw.Addr().As4()},
+		}
 	} else {
-		return 0, fmt.Errorf("unable to determine IP version from packet")
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: &netroute.Inet6Addr{IP: gw.Addr().As16()},
+		}
 	}
 
-	copy(buf[4:], from)
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
 
-	n, err := t.ReadWriteCloser.Write(buf)
+	_, err = unix.Write(sock, data[:])
-	return n - 4, err
+	if err != nil {
+		if errors.Is(err, unix.EEXIST) {
+			// Try to do a change
+			route.Type = unix.RTM_CHANGE
+			data, err = route.Marshal()
+			if err != nil {
+				return fmt.Errorf("failed to create route.RouteMessage for change: %w", err)
+			}
+			_, err = unix.Write(sock, data[:])
+			return err
+		}
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}
+
+func delRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_DELETE,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: &netroute.Inet4Addr{IP: gw.Addr().As4()},
+		}
+	} else {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: &netroute.Inet6Addr{IP: gw.Addr().As16()},
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
 }

pkclient/pkclient_cgo.go

@@ -180,6 +180,7 @@ func (c *PKClient) DeriveNoise(peerPubKey []byte) ([]byte, error) {
 		pkcs11.NewAttribute(pkcs11.CKA_DECRYPT, true),
 		pkcs11.NewAttribute(pkcs11.CKA_WRAP, true),
 		pkcs11.NewAttribute(pkcs11.CKA_UNWRAP, true),
+		pkcs11.NewAttribute(pkcs11.CKA_VALUE_LEN, NoiseKeySize),
 	}
 
 	// Set up the parameters which include the peer's public key

relay_manager.go

@@ -155,6 +155,8 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 		"vpnAddrs":            h.vpnAddrs}).
 		Info("handleCreateRelayResponse")
 
+	//peer == relayFrom
+	//target == relayTo
 	target := m.RelayToAddr
 	targetAddr := protoAddrToNetAddr(target)
 
@@ -190,11 +192,12 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 			InitiatorRelayIndex: peerRelay.RemoteIndex,
 		}
 
+		relayFrom := h.vpnAddrs[0]
 		if v == cert.Version1 {
 			peer := peerHostInfo.vpnAddrs[0]
 			if !peer.Is4() {
 				rm.l.WithField("relayFrom", peer).
-					WithField("relayTo", target).
+					WithField("relayTo", targetAddr).
 					WithField("initiatorRelayIndex", resp.InitiatorRelayIndex).
 					WithField("responderRelayIndex", resp.ResponderRelayIndex).
 					WithField("vpnAddrs", peerHostInfo.vpnAddrs).
@@ -207,7 +210,22 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 			b = targetAddr.As4()
 			resp.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
 		} else {
-			resp.RelayFromAddr = netAddrToProtoAddr(peerHostInfo.vpnAddrs[0])
+			ok = false
+			peerNetworks := h.GetCert().Certificate.Networks()
+			for i := range peerNetworks {
+				if peerNetworks[i].Contains(targetAddr) {
+					relayFrom = peerNetworks[i].Addr()
+					ok = true
+					break
+				}
+			}
+			if !ok {
+				rm.l.WithFields(logrus.Fields{"from": f.myVpnNetworks, "to": targetAddr}).
+					Error("cannot establish relay, no networks in common")
+				return
+			}
+
+			resp.RelayFromAddr = netAddrToProtoAddr(relayFrom)
 			resp.RelayToAddr = target
 		}
 
@@ -218,8 +236,8 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 		} else {
 			f.SendMessageToHostInfo(header.Control, 0, peerHostInfo, msg, make([]byte, 12), make([]byte, mtu))
 			rm.l.WithFields(logrus.Fields{
-				"relayFrom":           resp.RelayFromAddr,
+				"relayFrom":           relayFrom,
-				"relayTo":             resp.RelayToAddr,
+				"relayTo":             targetAddr,
 				"initiatorRelayIndex": resp.InitiatorRelayIndex,
 				"responderRelayIndex": resp.ResponderRelayIndex,
 				"vpnAddrs":            peerHostInfo.vpnAddrs}).
@@ -313,8 +331,7 @@ func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f
 
 		msg, err := resp.Marshal()
 		if err != nil {
-			logMsg.
+			logMsg.WithError(err).Error("relayManager Failed to marshal Control CreateRelayResponse message to create relay")
-				WithError(err).Error("relayManager Failed to marshal Control CreateRelayResponse message to create relay")
 		} else {
 			f.SendMessageToHostInfo(header.Control, 0, h, msg, make([]byte, 12), make([]byte, mtu))
 			rm.l.WithFields(logrus.Fields{
@@ -360,10 +377,10 @@ func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f
 			Type:                NebulaControl_CreateRelayRequest,
 			InitiatorRelayIndex: index,
 		}
-
+		relayFrom := h.vpnAddrs[0]
 		if v == cert.Version1 {
-			if !h.vpnAddrs[0].Is4() {
+			if !relayFrom.Is4() {
-				rm.l.WithField("relayFrom", h.vpnAddrs[0]).
+				rm.l.WithField("relayFrom", relayFrom).
 					WithField("relayTo", target).
 					WithField("initiatorRelayIndex", req.InitiatorRelayIndex).
 					WithField("responderRelayIndex", req.ResponderRelayIndex).
@@ -372,23 +389,37 @@ func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f
 				return
 			}
 
-			b := h.vpnAddrs[0].As4()
+			b := relayFrom.As4()
 			req.OldRelayFromAddr = binary.BigEndian.Uint32(b[:])
 			b = target.As4()
 			req.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
 		} else {
-			req.RelayFromAddr = netAddrToProtoAddr(h.vpnAddrs[0])
+			ok = false
+			peerNetworks := h.GetCert().Certificate.Networks()
+			for i := range peerNetworks {
+				if peerNetworks[i].Contains(target) {
+					relayFrom = peerNetworks[i].Addr()
+					ok = true
+					break
+				}
+			}
+			if !ok {
+				rm.l.WithFields(logrus.Fields{"from": f.myVpnNetworks, "to": target}).
+					Error("cannot establish relay, no networks in common")
+				return
+			}
+
+			req.RelayFromAddr = netAddrToProtoAddr(relayFrom)
 			req.RelayToAddr = netAddrToProtoAddr(target)
 		}
 
 		msg, err := req.Marshal()
 		if err != nil {
-			logMsg.
+			logMsg.WithError(err).Error("relayManager Failed to marshal Control message to create relay")
-				WithError(err).Error("relayManager Failed to marshal Control message to create relay")
 		} else {
 			f.SendMessageToHostInfo(header.Control, 0, peer, msg, make([]byte, 12), make([]byte, mtu))
 			rm.l.WithFields(logrus.Fields{
-				"relayFrom":           h.vpnAddrs[0],
+				"relayFrom":           relayFrom,
 				"relayTo":             target,
 				"initiatorRelayIndex": req.InitiatorRelayIndex,
 				"responderRelayIndex": req.ResponderRelayIndex,
@@ -401,8 +432,7 @@ func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f
 		if !ok {
 			_, err := AddRelay(rm.l, h, f.hostMap, target, &m.InitiatorRelayIndex, ForwardingType, PeerRequested)
 			if err != nil {
-				logMsg.
+				logMsg.WithError(err).Error("relayManager Failed to allocate a local index for relay")
-					WithError(err).Error("relayManager Failed to allocate a local index for relay")
 				return
 			}
 		}

remote_list.go

@@ -190,7 +190,7 @@ type RemoteList struct {
 	// The full list of vpn addresses assigned to this host
 	vpnAddrs []netip.Addr
 
-	// A deduplicated set of addresses. Any accessor should lock beforehand.
+	// A deduplicated set of underlay addresses. Any accessor should lock beforehand.
 	addrs []netip.AddrPort
 
 	// A set of relay addresses. VpnIp addresses that the remote identified as relays.
@@ -201,8 +201,10 @@ type RemoteList struct {
 	// For learned addresses, this is the vpnIp that sent the packet
 	cache map[netip.Addr]*cache
 
-	hr        *hostnamesResults
+	hr *hostnamesResults
-	shouldAdd func(netip.Addr) bool
+
+	// shouldAdd is a nillable function that decides if x should be added to addrs.
+	shouldAdd func(vpnAddrs []netip.Addr, x netip.Addr) bool
 
 	// This is a list of remotes that we have tried to handshake with and have returned from the wrong vpn ip.
 	// They should not be tried again during a handshake
@@ -213,7 +215,7 @@ type RemoteList struct {
 }
 
 // NewRemoteList creates a new empty RemoteList
-func NewRemoteList(vpnAddrs []netip.Addr, shouldAdd func(netip.Addr) bool) *RemoteList {
+func NewRemoteList(vpnAddrs []netip.Addr, shouldAdd func([]netip.Addr, netip.Addr) bool) *RemoteList {
 	r := &RemoteList{
 		vpnAddrs:  make([]netip.Addr, len(vpnAddrs)),
 		addrs:     make([]netip.AddrPort, 0),
@@ -368,6 +370,15 @@ func (r *RemoteList) CopyBlockedRemotes() []netip.AddrPort {
 	return c
 }
 
+// RefreshFromHandshake locks and updates the RemoteList to account for data learned upon a completed handshake
+func (r *RemoteList) RefreshFromHandshake(vpnAddrs []netip.Addr) {
+	r.Lock()
+	r.badRemotes = nil
+	r.vpnAddrs = make([]netip.Addr, len(vpnAddrs))
+	copy(r.vpnAddrs, vpnAddrs)
+	r.Unlock()
+}
+
 // ResetBlockedRemotes locks and clears the blocked remotes list
 func (r *RemoteList) ResetBlockedRemotes() {
 	r.Lock()
@@ -577,7 +588,7 @@ func (r *RemoteList) unlockedCollect() {
 
 	dnsAddrs := r.hr.GetAddrs()
 	for _, addr := range dnsAddrs {
-		if r.shouldAdd == nil || r.shouldAdd(addr.Addr()) {
+		if r.shouldAdd == nil || r.shouldAdd(r.vpnAddrs, addr.Addr()) {
 			if !r.unlockedIsBad(addr) {
 				addrs = append(addrs, addr)
 			}