Address PR feedback: remove outbound rate limit, improve config docs

Remove rate limiting from StartHandshake (outbound) since DoS
protection only needs to limit inbound handshakes. This also avoids
returning nil from StartHandshake which historically always returned
non-nil. Update config comment to note openssl speed is single-core
and suggest scaling by routines.

Co-Authored-By: Claude <svc-devxp-claude@slack-corp.com>

CODEOWNERS

@@ -0,0 +1 @@
+#ECCN:Open Source

cert/cert_v2.go

@@ -439,7 +439,11 @@ func (c *certificateV2) validate() error {
 				if !hasV6Networks {
 					return NewErrInvalidCertificateProperties("IPv6 unsafe networks require an IPv6 address assignment: %s", network)
 				}
-			} // as long as we have any IP address, IPv4 UnsafeNetworks are allowed
+			} else if network.Addr().Is4() {
+				if !hasV4Networks {
+					return NewErrInvalidCertificateProperties("IPv4 unsafe networks require an IPv4 address assignment: %s", network)
+				}
+			}
 		}
 	}
 

dist/wireshark/nebula.lua

@@ -84,30 +84,24 @@ end
 
 function nebula.prefs_changed()
     if default_settings.all_ports == nebula.prefs.all_ports and default_settings.port == nebula.prefs.port then
-        -- Nothing changed, bail
         return
     end
 
-    -- Remove our old dissector
+    -- Remove all existing registrations
     DissectorTable.get("udp.port"):remove_all(nebula)
 
-    if nebula.prefs.all_ports and default_settings.all_ports ~= nebula.prefs.all_ports then
+    if nebula.prefs.all_ports then
-        default_settings.all_port = nebula.prefs.all_ports
+        -- Register on every port for hole punch capture
-
         for i=0, 65535 do
             DissectorTable.get("udp.port"):add(i, nebula)
         end
-
+    else
-        -- no need to establish again on specific ports
+        -- Register on the configured port only
-        return
+        DissectorTable.get("udp.port"):add(nebula.prefs.port, nebula)
     end
 
-
+    default_settings.all_ports = nebula.prefs.all_ports
-    if default_settings.all_ports ~= nebula.prefs.all_ports then
+    default_settings.port = nebula.prefs.port
-        -- Add our new port dissector
-        default_settings.port = nebula.prefs.port
-        DissectorTable.get("udp.port"):add(default_settings.port, nebula)
-    end
 end
 
 DissectorTable.get("udp.port"):add(default_settings.port, nebula)

e2e/snat_test.go

@@ -1,400 +0,0 @@
-//go:build e2e_testing
-// +build e2e_testing
-
-package e2e
-
-import (
-	"encoding/binary"
-	"net/netip"
-	"testing"
-	"time"
-
-	"github.com/slackhq/nebula/cert"
-	"github.com/slackhq/nebula/cert_test"
-	"github.com/slackhq/nebula/e2e/router"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// parseIPv4UDPPacket extracts source/dest IPs, ports, and payload from an IPv4 UDP packet.
-func parseIPv4UDPPacket(t testing.TB, pkt []byte) (srcIP, dstIP netip.Addr, srcPort, dstPort uint16, payload []byte) {
-	t.Helper()
-	require.True(t, len(pkt) >= 28, "packet too short for IPv4+UDP header")
-	require.Equal(t, byte(0x45), pkt[0]&0xF0|pkt[0]&0x0F, "not a simple IPv4 packet (IHL!=5)")
-
-	srcIP, _ = netip.AddrFromSlice(pkt[12:16])
-	dstIP, _ = netip.AddrFromSlice(pkt[16:20])
-
-	ihl := int(pkt[0]&0x0F) * 4
-	require.True(t, len(pkt) >= ihl+8, "packet too short for UDP header")
-	srcPort = binary.BigEndian.Uint16(pkt[ihl : ihl+2])
-	dstPort = binary.BigEndian.Uint16(pkt[ihl+2 : ihl+4])
-	udpLen := binary.BigEndian.Uint16(pkt[ihl+4 : ihl+6])
-	payload = pkt[ihl+8 : ihl+int(udpLen)]
-	return
-}
-
-func TestSNAT_IPv6OnlyPeer_IPv4UnsafeTraffic(t *testing.T) {
-	// Scenario: Two IPv6-only VPN nodes. The "router" node has unsafe networks
-	// (192.168.0.0/16) in its cert and a configured SNAT address. The "sender"
-	// node has an unsafe route for 192.168.0.0/16 via the router.
-	//
-	// When sender injects an IPv4 packet destined for the unsafe network, it
-	// gets tunneled to the router. The router's firewall detects this is IPv4
-	// from an IPv6-only peer and applies SNAT, rewriting the source IP to the
-	// SNAT address before delivering it to TUN.
-	//
-	// When a reply comes back from TUN addressed to the SNAT address, the
-	// router un-SNATs it (restoring the original destination) and tunnels it
-	// back to the sender.
-
-	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-
-	unsafePrefix := "192.168.0.0/16"
-	snatAddr := netip.MustParseAddr("169.254.42.42")
-
-	// Router: IPv6-only with unsafe networks and a manual SNAT address.
-	// Override inbound firewall with local_cidr: "any" so both IPv4 (unsafe)
-	// and IPv6 (VPN) traffic is accepted.
-	routerControl, routerVpnIpNet, routerUdpAddr, _ := newSimpleServerWithUdpAndUnsafeNetworks(
-		cert.Version2, ca, caKey, "router", "ff::1/64",
-		netip.MustParseAddrPort("[beef::1]:4242"),
-		unsafePrefix,
-		m{
-			"firewall": m{
-				"inbound": []m{{
-					"proto":      "any",
-					"port":       "any",
-					"host":       "any",
-					"local_cidr": "any",
-				}},
-			},
-			"tun": m{
-				"snat_address_for_4over6": snatAddr.String(),
-			},
-		},
-	)
-
-	// Sender: IPv6-only with an unsafe route via the router
-	senderControl, _, _, _ := newSimpleServerWithUdp(
-		cert.Version2, ca, caKey, "sender", "ff::2/64",
-		netip.MustParseAddrPort("[beef::2]:4242"),
-		m{
-			"tun": m{
-				"unsafe_routes": []m{
-					{"route": unsafePrefix, "via": routerVpnIpNet[0].Addr().String()},
-				},
-			},
-		},
-	)
-
-	// Tell sender where the router lives
-	senderControl.InjectLightHouseAddr(routerVpnIpNet[0].Addr(), routerUdpAddr)
-
-	// Build the router and start both nodes
-	r := router.NewR(t, routerControl, senderControl)
-	defer r.RenderFlow()
-
-	routerControl.Start()
-	senderControl.Start()
-
-	// --- Outbound: sender -> IPv4 unsafe dest (via router with SNAT) ---
-
-	origSrcIP := netip.MustParseAddr("10.0.0.1")
-	unsafeDest := netip.MustParseAddr("192.168.1.1")
-	var origSrcPort uint16 = 12345
-	var dstPort uint16 = 80
-
-	t.Log("Sender injects an IPv4 packet to the unsafe network")
-	senderControl.InjectTunUDPPacket(unsafeDest, dstPort, origSrcIP, origSrcPort, []byte("snat me"))
-
-	t.Log("Route packets (handshake + data) until the router gets the packet on TUN")
-	snatPkt := r.RouteForAllUntilTxTun(routerControl)
-
-	t.Log("Verify the packet was SNATted")
-	gotSrcIP, gotDstIP, gotSrcPort, gotDstPort, gotPayload := parseIPv4UDPPacket(t, snatPkt)
-	assert.Equal(t, snatAddr, gotSrcIP, "source IP should be rewritten to the SNAT address")
-	assert.Equal(t, unsafeDest, gotDstIP, "destination IP should be unchanged")
-	assert.Equal(t, dstPort, gotDstPort, "destination port should be unchanged")
-	assert.Equal(t, []byte("snat me"), gotPayload, "payload should be unchanged")
-
-	// Capture the SNAT port (may differ from original if port was remapped)
-	snatPort := gotSrcPort
-	t.Logf("SNAT port: %d (original: %d)", snatPort, origSrcPort)
-
-	// --- Return: reply from unsafe dest -> un-SNATted back to sender ---
-
-	t.Log("Router injects a reply packet from the unsafe dest to the SNAT address")
-	routerControl.InjectTunUDPPacket(snatAddr, snatPort, unsafeDest, dstPort, []byte("reply from unsafe"))
-
-	t.Log("Route until sender gets the reply on TUN")
-	replyPkt := r.RouteForAllUntilTxTun(senderControl)
-
-	t.Log("Verify the reply was un-SNATted")
-	replySrcIP, replyDstIP, replySrcPort, replyDstPort, replyPayload := parseIPv4UDPPacket(t, replyPkt)
-	assert.Equal(t, unsafeDest, replySrcIP, "reply source should be the unsafe dest")
-	assert.Equal(t, origSrcIP, replyDstIP, "reply dest should be the original source IP (un-SNATted)")
-	assert.Equal(t, dstPort, replySrcPort, "reply source port should be the unsafe dest port")
-	assert.Equal(t, origSrcPort, replyDstPort, "reply dest port should be the original source port (un-SNATted)")
-	assert.Equal(t, []byte("reply from unsafe"), replyPayload, "payload should be unchanged")
-
-	r.RenderHostmaps("Final hostmaps", routerControl, senderControl)
-
-	// Also verify normal IPv6 VPN traffic still works between the nodes
-	t.Log("Verify normal IPv6 VPN tunnel still works")
-	assertTunnel(t, routerVpnIpNet[0].Addr(), senderControl.GetVpnAddrs()[0], routerControl, senderControl, r)
-
-	routerControl.Stop()
-	senderControl.Stop()
-}
-
-func TestSNAT_MultipleFlows(t *testing.T) {
-	// Test that multiple distinct IPv4 flows from the same IPv6-only peer
-	// are tracked independently through SNAT.
-
-	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-
-	unsafePrefix := "192.168.0.0/16"
-	snatAddr := netip.MustParseAddr("169.254.42.42")
-
-	routerControl, routerVpnIpNet, routerUdpAddr, _ := newSimpleServerWithUdpAndUnsafeNetworks(
-		cert.Version2, ca, caKey, "router", "ff::1/64",
-		netip.MustParseAddrPort("[beef::1]:4242"),
-		unsafePrefix,
-		m{
-			"firewall": m{
-				"inbound": []m{{
-					"proto":      "any",
-					"port":       "any",
-					"host":       "any",
-					"local_cidr": "any",
-				}},
-			},
-			"tun": m{
-				"snat_address_for_4over6": snatAddr.String(),
-			},
-		},
-	)
-
-	senderControl, _, _, _ := newSimpleServerWithUdp(
-		cert.Version2, ca, caKey, "sender", "ff::2/64",
-		netip.MustParseAddrPort("[beef::2]:4242"),
-		m{
-			"tun": m{
-				"unsafe_routes": []m{
-					{"route": unsafePrefix, "via": routerVpnIpNet[0].Addr().String()},
-				},
-			},
-		},
-	)
-
-	senderControl.InjectLightHouseAddr(routerVpnIpNet[0].Addr(), routerUdpAddr)
-
-	r := router.NewR(t, routerControl, senderControl)
-	defer r.RenderFlow()
-	r.CancelFlowLogs()
-
-	routerControl.Start()
-	senderControl.Start()
-
-	unsafeDest := netip.MustParseAddr("192.168.1.1")
-
-	// Send first flow
-	senderControl.InjectTunUDPPacket(unsafeDest, 80, netip.MustParseAddr("10.0.0.1"), 1111, []byte("flow1"))
-	pkt1 := r.RouteForAllUntilTxTun(routerControl)
-	srcIP1, _, srcPort1, _, payload1 := parseIPv4UDPPacket(t, pkt1)
-	assert.Equal(t, snatAddr, srcIP1)
-	assert.Equal(t, []byte("flow1"), payload1)
-
-	// Send second flow (different source port)
-	senderControl.InjectTunUDPPacket(unsafeDest, 80, netip.MustParseAddr("10.0.0.1"), 2222, []byte("flow2"))
-	pkt2 := r.RouteForAllUntilTxTun(routerControl)
-	srcIP2, _, srcPort2, _, payload2 := parseIPv4UDPPacket(t, pkt2)
-	assert.Equal(t, snatAddr, srcIP2)
-	assert.Equal(t, []byte("flow2"), payload2)
-
-	// The two flows should have different SNAT ports (since they're different conntracks)
-	t.Logf("Flow 1 SNAT port: %d, Flow 2 SNAT port: %d", srcPort1, srcPort2)
-
-	// Reply to flow 2 first (out of order)
-	routerControl.InjectTunUDPPacket(snatAddr, srcPort2, unsafeDest, 80, []byte("reply2"))
-	reply2 := r.RouteForAllUntilTxTun(senderControl)
-	_, replyDst2, _, replyDstPort2, replyPayload2 := parseIPv4UDPPacket(t, reply2)
-	assert.Equal(t, netip.MustParseAddr("10.0.0.1"), replyDst2)
-	assert.Equal(t, uint16(2222), replyDstPort2, "reply to flow 2 should restore original port 2222")
-	assert.Equal(t, []byte("reply2"), replyPayload2)
-
-	// Reply to flow 1
-	routerControl.InjectTunUDPPacket(snatAddr, srcPort1, unsafeDest, 80, []byte("reply1"))
-	reply1 := r.RouteForAllUntilTxTun(senderControl)
-	_, replyDst1, _, replyDstPort1, replyPayload1 := parseIPv4UDPPacket(t, reply1)
-	assert.Equal(t, netip.MustParseAddr("10.0.0.1"), replyDst1)
-	assert.Equal(t, uint16(1111), replyDstPort1, "reply to flow 1 should restore original port 1111")
-	assert.Equal(t, []byte("reply1"), replyPayload1)
-
-	routerControl.Stop()
-	senderControl.Stop()
-}
-
-// --- Adversarial SNAT E2E Tests ---
-
-func TestSNAT_UnsolicitedReplyDropped(t *testing.T) {
-	// Without any outbound SNAT traffic, inject a packet from the router's TUN
-	// addressed to the SNAT address. The sender must never receive it because
-	// there's no conntrack entry to un-SNAT through.
-
-	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-
-	unsafePrefix := "192.168.0.0/16"
-	snatAddr := netip.MustParseAddr("169.254.42.42")
-
-	routerControl, routerVpnIpNet, routerUdpAddr, _ := newSimpleServerWithUdpAndUnsafeNetworks(
-		cert.Version2, ca, caKey, "router", "ff::1/64",
-		netip.MustParseAddrPort("[beef::1]:4242"),
-		unsafePrefix,
-		m{
-			"firewall": m{
-				"inbound": []m{{
-					"proto":      "any",
-					"port":       "any",
-					"host":       "any",
-					"local_cidr": "any",
-				}},
-			},
-			"tun": m{
-				"snat_address_for_4over6": snatAddr.String(),
-			},
-		},
-	)
-
-	senderControl, _, _, _ := newSimpleServerWithUdp(
-		cert.Version2, ca, caKey, "sender", "ff::2/64",
-		netip.MustParseAddrPort("[beef::2]:4242"),
-		m{
-			"tun": m{
-				"unsafe_routes": []m{
-					{"route": unsafePrefix, "via": routerVpnIpNet[0].Addr().String()},
-				},
-			},
-		},
-	)
-
-	senderControl.InjectLightHouseAddr(routerVpnIpNet[0].Addr(), routerUdpAddr)
-
-	r := router.NewR(t, routerControl, senderControl)
-	defer r.RenderFlow()
-	r.CancelFlowLogs()
-
-	routerControl.Start()
-	senderControl.Start()
-
-	// First establish the tunnel with normal IPv6 traffic so handshake completes
-	assertTunnel(t, routerVpnIpNet[0].Addr(), senderControl.GetVpnAddrs()[0], routerControl, senderControl, r)
-
-	// Inject the unsolicited reply from router's TUN to the SNAT address.
-	// There is NO prior outbound SNAT flow, so no conntrack entry exists.
-	// The router should silently drop this because unSnat finds no matching conntrack.
-	routerControl.InjectTunUDPPacket(snatAddr, 55555, netip.MustParseAddr("192.168.1.1"), 80, []byte("unsolicited"))
-
-	// Send a canary IPv6 VPN packet after the bad one. Since the router processes
-	// TUN packets sequentially, the canary arriving proves the bad packet was processed first.
-	senderVpnAddr := senderControl.GetVpnAddrs()[0]
-	routerControl.InjectTunUDPPacket(senderVpnAddr, 90, routerVpnIpNet[0].Addr(), 80, []byte("canary"))
-	canaryPkt := r.RouteForAllUntilTxTun(senderControl)
-	assertUdpPacket(t, []byte("canary"), canaryPkt, routerVpnIpNet[0].Addr(), senderVpnAddr, 80, 90)
-
-	// The unsolicited packet should have been dropped — nothing else on sender's TUN
-	got := senderControl.GetFromTun(false)
-	assert.Nil(t, got, "sender should not receive unsolicited packet to SNAT address with no conntrack entry")
-
-	routerControl.Stop()
-	senderControl.Stop()
-}
-
-func TestSNAT_NonUnsafeDestDropped(t *testing.T) {
-	// An IPv6-only sender sends IPv4 traffic to a destination outside the router's
-	// unsafe networks (172.16.0.1 when unsafe is 192.168.0.0/16). The router should
-	// reject this because the local address is not routable. This verifies that
-	// willingToHandleLocalAddr enforces boundaries on what SNAT traffic can reach.
-
-	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-
-	unsafePrefix := "192.168.0.0/16"
-	snatAddr := netip.MustParseAddr("169.254.42.42")
-
-	routerControl, routerVpnIpNet, routerUdpAddr, _ := newSimpleServerWithUdpAndUnsafeNetworks(
-		cert.Version2, ca, caKey, "router", "ff::1/64",
-		netip.MustParseAddrPort("[beef::1]:4242"),
-		unsafePrefix,
-		m{
-			"firewall": m{
-				"inbound": []m{{
-					"proto":      "any",
-					"port":       "any",
-					"host":       "any",
-					"local_cidr": "any",
-				}},
-			},
-			"tun": m{
-				"snat_address_for_4over6": snatAddr.String(),
-			},
-		},
-	)
-
-	// Sender has unsafe routes for BOTH 192.168.0.0/16 AND 172.16.0.0/12 via router.
-	// This means the sender will route 172.16.0.1 through the tunnel to the router.
-	// But the router should reject it because 172.16.0.0/12 is NOT in its unsafe networks.
-	senderControl, _, _, _ := newSimpleServerWithUdp(
-		cert.Version2, ca, caKey, "sender", "ff::2/64",
-		netip.MustParseAddrPort("[beef::2]:4242"),
-		m{
-			"tun": m{
-				"unsafe_routes": []m{
-					{"route": unsafePrefix, "via": routerVpnIpNet[0].Addr().String()},
-					{"route": "172.16.0.0/12", "via": routerVpnIpNet[0].Addr().String()},
-				},
-			},
-		},
-	)
-
-	senderControl.InjectLightHouseAddr(routerVpnIpNet[0].Addr(), routerUdpAddr)
-
-	r := router.NewR(t, routerControl, senderControl)
-	defer r.RenderFlow()
-	r.CancelFlowLogs()
-
-	routerControl.Start()
-	senderControl.Start()
-
-	// Establish the tunnel first
-	assertTunnel(t, routerVpnIpNet[0].Addr(), senderControl.GetVpnAddrs()[0], routerControl, senderControl, r)
-
-	// Send to 172.16.0.1 (NOT in router's unsafe networks 192.168.0.0/16).
-	// The router should reject this at willingToHandleLocalAddr.
-	senderControl.InjectTunUDPPacket(
-		netip.MustParseAddr("172.16.0.1"), 80,
-		netip.MustParseAddr("10.0.0.1"), 12345,
-		[]byte("wrong dest"),
-	)
-
-	// Send a canary to a valid unsafe destination to prove the bad packet was processed
-	senderControl.InjectTunUDPPacket(
-		netip.MustParseAddr("192.168.1.1"), 80,
-		netip.MustParseAddr("10.0.0.1"), 33333,
-		[]byte("canary"),
-	)
-
-	// Route until the canary arrives — the 172.16.0.1 packet should have been
-	// processed and dropped before the canary gets through
-	canaryPkt := r.RouteForAllUntilTxTun(routerControl)
-	_, canaryDst, _, _, canaryPayload := parseIPv4UDPPacket(t, canaryPkt)
-	assert.Equal(t, netip.MustParseAddr("192.168.1.1"), canaryDst, "canary should arrive at the valid unsafe dest")
-	assert.Equal(t, []byte("canary"), canaryPayload)
-
-	// No more packets — the 172.16.0.1 packet was dropped
-	got := routerControl.GetFromTun(false)
-	assert.Nil(t, got, "packet to non-unsafe destination 172.16.0.1 should be dropped by the router")
-
-	routerControl.Stop()
-	senderControl.Stop()
-}

e2e/tunnels_test.go

@@ -12,6 +12,8 @@ import (
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/cert_test"
 	"github.com/slackhq/nebula/e2e/router"
+	"github.com/slackhq/nebula/header"
+	"github.com/slackhq/nebula/udp"
 	"github.com/stretchr/testify/assert"
 	"gopkg.in/yaml.v3"
 )
@@ -365,3 +367,106 @@ func TestCrossStackRelaysWork(t *testing.T) {
 	//theirControl.Stop()
 	//relayControl.Stop()
 }
+
+func TestCloseTunnelAuthenticated(t *testing.T) {
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	myControl, myVpnIpNet, myUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "me", "10.128.0.1/24", m{"tunnels": m{"drop_inactive": true, "inactivity_timeout": "5s"}})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "them", "10.128.0.2/24", m{"tunnels": m{"drop_inactive": true, "inactivity_timeout": "10m"}})
+
+	// Share our underlay information
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	r := router.NewR(t, myControl, theirControl)
+
+	r.Log("Assert the tunnel between me and them works")
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+
+	r.Log("Close the tunnel")
+	myControl.CloseTunnel(theirVpnIpNet[0].Addr(), false)
+	r.FlushAll()
+
+	waitStart := time.Now()
+	for {
+		myIndexes := len(myControl.GetHostmap().Indexes)
+		theirIndexes := len(theirControl.GetHostmap().Indexes)
+		if myIndexes == 0 && theirIndexes == 0 {
+			break
+		}
+
+		since := time.Since(waitStart)
+		r.Logf("my tunnels: %v; their tunnels: %v; duration: %v", myIndexes, theirIndexes, since)
+		if since > time.Second*6 {
+			t.Fatal("Tunnel should have been declared inactive after 2 seconds and before 6 seconds")
+		}
+
+		time.Sleep(1 * time.Second)
+		//r.FlushAll()
+	}
+
+	r.Logf("Happy path success, tunnels were dropped within %v", time.Since(waitStart))
+
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+	r.Log("Assert another tunnel between me and them works")
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+	hi := myControl.GetHostInfoByVpnAddr(theirVpnIpNet[0].Addr(), false)
+	if hi == nil {
+		t.Fatal("There is no hostinfo for this tunnel")
+	}
+	myHi := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
+	if myHi == nil {
+		t.Fatal("There is no hostinfo for my tunnel")
+	}
+	r.Log("It does")
+
+	buf := make([]byte, 1024)
+	hdr := header.H{
+		Version:        1,
+		Type:           header.CloseTunnel,
+		Subtype:        0,
+		Reserved:       0,
+		RemoteIndex:    hi.RemoteIndex,
+		MessageCounter: 5,
+	}
+	out, err := hdr.Encode(buf)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	pkt := &udp.Packet{
+		To:   hi.CurrentRemote,
+		From: myHi.CurrentRemote,
+		Data: out,
+	}
+	r.InjectUDPPacket(myControl, theirControl, pkt)
+	r.Log("Injected bogus close tunnel. Let's see!")
+	waitStart = time.Now()
+	for {
+		myIndexes := len(myControl.GetHostmap().Indexes)
+		theirIndexes := len(theirControl.GetHostmap().Indexes)
+		if myIndexes == 0 {
+			t.Fatal("myIndexes should not be 0")
+		}
+		if theirIndexes == 0 {
+			t.Fatal("theirIndexes should not be 0, they should have rejected this bogus packet")
+		}
+
+		since := time.Since(waitStart)
+		r.Logf("my tunnels: %v; their tunnels: %v; duration: %v", myIndexes, theirIndexes, since)
+		if since > time.Second*4 {
+			t.Log("The tunnel would have been gone by now")
+			break
+		}
+
+		time.Sleep(1 * time.Second)
+		r.FlushAll()
+	}
+
+	myControl.Stop()
+	theirControl.Stop()
+}

examples/config.yml

@@ -283,15 +283,6 @@ tun:
   # If using massive routes updates, for example BGP, you may need to increase this value to avoid packet loss.
   # SO_RCVBUFFORCE is used to avoid having to raise the system wide max
   #use_system_route_table_buffer_size: 0
-  #
-  # When using the feature to carry IPv4 unsafe_routes through a IPv6-only overlay network (4over6),
-  # the system still needs to use IPv4 addresses to pass that traffic. 
-  # By default, they are randomly chosen out of 169.254.0.0/16 at startup, but if you need them to be static, you can set them here.
-  # Setting these options is not required for use of the 4over6 feature.
-  # this is the address that a client will use as a source IP for packets sent to the router
-  #unsafe_origin_address_for_4over6: 169.254.55.96
-  # this is the IP the router will use internally to hairpin-NAT 4over6 traffic before it hits the operating system.
-  #snat_address_for_4over6: 169.254.12.34
 
 # Configure logging level
 logging:
@@ -351,6 +342,14 @@ logging:
   # after receiving the response for lighthouse queries
   #trigger_buffer: 64
 
+  # max_rate limits the number of new inbound handshakes per second. Once the limit is reached,
+  # new handshakes are dropped until the next second. A value of 0 means unlimited (default).
+  # This is useful for preventing DoS attacks that attempt to exhaust CPU with handshake crypto.
+  # Running `openssl speed ecdhp256` on your hardware can be a good rule of thumb for choosing
+  # a max, as each handshake performs similar DH operations. Note that this benchmarks a single
+  # core, so you may wish to scale the value by the number of `routines` configured.
+  #max_rate: 0
+
 # Tunnel manager settings
 #tunnels:
   # drop_inactive controls whether inactive tunnels are maintained or dropped after the inactive_timeout period has

firewall.go

@@ -2,7 +2,6 @@ package nebula
 
 import (
 	"crypto/sha256"
-	"encoding/binary"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -23,35 +22,10 @@ import (
 	"github.com/slackhq/nebula/firewall"
 )
 
-var ErrCannotSNAT = errors.New("cannot SNAT this packet")
-var ErrSNATIdentityMismatch = errors.New("refusing to SNAT for mismatched host")
-var ErrSNATAddressCollision = errors.New("refusing to accept an incoming packet with my SNAT address")
-
-const ipv4SourcePosition = 12
-const ipv4DestinationPosition = 16
-const sourcePortOffset = 0
-const destinationPortOffset = 2
-
 type FirewallInterface interface {
 	AddRule(incoming bool, proto uint8, startPort int32, endPort int32, groups []string, host string, cidr, localCidr string, caName string, caSha string) error
 }
 
-type snatInfo struct {
-	//Src is the source IP+port to write into unsafe-route-bound packet
-	Src netip.AddrPort
-	//SrcVpnIp is the overlay IP associated with this flow. It's needed to associate reply traffic so we can get it back to the right host.
-	SrcVpnIp netip.Addr
-	//SnatPort is the port to rewrite into an overlay-bound packet
-	SnatPort uint16
-}
-
-func (s *snatInfo) Valid() bool {
-	if s == nil {
-		return false
-	}
-	return s.Src.IsValid()
-}
-
 type conn struct {
 	Expires time.Time // Time when this conntrack entry will expire
 
@@ -60,9 +34,6 @@ type conn struct {
 	// fields pack for free after the uint32 above
 	incoming     bool
 	rulesVersion uint16
-
-	//for SNAT support
-	snat *snatInfo
 }
 
 // TODO: need conntrack max tracked connections handling
@@ -95,8 +66,6 @@ type Firewall struct {
 	defaultLocalCIDRAny bool
 	incomingMetrics     firewallMetrics
 	outgoingMetrics     firewallMetrics
-	unsafeIPv4Origin    netip.Addr
-	snatAddr            netip.Addr
 
 	l *logrus.Logger
 }
@@ -224,12 +193,12 @@ func NewFirewall(l *logrus.Logger, tcpTimeout, UDPTimeout, defaultTimeout time.D
 
 func NewFirewallFromConfig(l *logrus.Logger, cs *CertState, c *config.C) (*Firewall, error) {
 	certificate := cs.getCertificate(cert.Version2)
-	if certificate == nil { //todo if config.initiating_version is set to 1, and unsafe_networks differ, things will suck
+	if certificate == nil {
 		certificate = cs.getCertificate(cert.Version1)
 	}
 
 	if certificate == nil {
-		return nil, errors.New("no certificate available to reconfigure the firewall")
+		panic("No certificate available to reconfigure the firewall")
 	}
 
 	fw := NewFirewall(
@@ -238,6 +207,7 @@ func NewFirewallFromConfig(l *logrus.Logger, cs *CertState, c *config.C) (*Firew
 		c.GetDuration("firewall.conntrack.udp_timeout", time.Minute*3),
 		c.GetDuration("firewall.conntrack.default_timeout", time.Minute*10),
 		certificate,
+		//TODO: max_connections
 	)
 
 	fw.defaultLocalCIDRAny = c.GetBool("firewall.default_local_cidr_any", false)
@@ -260,7 +230,7 @@ func NewFirewallFromConfig(l *logrus.Logger, cs *CertState, c *config.C) (*Firew
 	case "drop":
 		fw.OutSendReject = false
 	default:
-		l.WithField("action", inboundAction).Warn("invalid firewall.outbound_action, defaulting to `drop`")
+		l.WithField("action", outboundAction).Warn("invalid firewall.outbound_action, defaulting to `drop`")
 		fw.OutSendReject = false
 	}
 
@@ -344,18 +314,6 @@ func (f *Firewall) GetRuleHashes() string {
 	return "SHA:" + f.GetRuleHash() + ",FNV:" + strconv.FormatUint(uint64(f.GetRuleHashFNV()), 10)
 }
 
-func (f *Firewall) SetSNATAddressFromInterface(i *Interface) {
-	//address-mutation-avoidance is done inside Interface, the firewall doesn't need to care
-	//todo should snatted conntracks get expired out? Probably not needed until if/when we allow reload
-	f.snatAddr = i.inside.SNATAddress().Addr()
-	f.unsafeIPv4Origin = i.inside.UnsafeIPv4OriginAddress().Addr()
-}
-
-func (f *Firewall) ShouldUnSNAT(fp *firewall.Packet) bool {
-	// f.snatAddr is only valid if we're a snat-capable router
-	return f.snatAddr.IsValid() && fp.RemoteAddr == f.snatAddr
-}
-
 func AddFirewallRulesFromConfig(l *logrus.Logger, inbound bool, c *config.C, fw FirewallInterface) error {
 	var table string
 	if inbound {
@@ -456,207 +414,50 @@ var ErrInvalidRemoteIP = errors.New("remote address is not in remote certificate
 var ErrInvalidLocalIP = errors.New("local address is not in list of handled local addresses")
 var ErrNoMatchingRule = errors.New("no matching rule in firewall table")
 
-func (f *Firewall) unSnat(data []byte, fp *firewall.Packet) netip.Addr {
-	c := f.peek(*fp) //unfortunately this needs to lock. Surely there's a better way.
-	if c == nil {
-		return netip.Addr{}
-	}
-	if !c.snat.Valid() {
-		return netip.Addr{}
-	}
-	oldIP := netip.AddrPortFrom(f.snatAddr, fp.RemotePort)
-	rewritePacket(data, fp, oldIP, c.snat.Src, ipv4DestinationPosition, destinationPortOffset)
-	return c.snat.SrcVpnIp
-}
-
-func rewritePacket(data []byte, fp *firewall.Packet, oldIP netip.AddrPort, newIP netip.AddrPort, ipOffset int, portOffset int) {
-	//change address
-	copy(data[ipOffset:], newIP.Addr().AsSlice())
-	recalcIPv4Checksum(data, oldIP.Addr(), newIP.Addr())
-	ipHeaderLen := int(data[0]&0x0F) * 4
-
-	switch fp.Protocol {
-	case firewall.ProtoICMP:
-		binary.BigEndian.PutUint16(data[ipHeaderLen+4:ipHeaderLen+6], newIP.Port()) //we use the ID field as a "port" for ICMP
-		icmpCode := uint16(data[ipHeaderLen+1])                                     //todo not snatting on code yet (but Linux would)
-		recalcICMPv4Checksum(data, icmpCode, icmpCode, oldIP.Port(), newIP.Port())
-	case firewall.ProtoUDP:
-		dstport := ipHeaderLen + portOffset
-		binary.BigEndian.PutUint16(data[dstport:dstport+2], newIP.Port())
-		recalcUDPv4Checksum(data, oldIP, newIP)
-	case firewall.ProtoTCP:
-		dstport := ipHeaderLen + portOffset
-		binary.BigEndian.PutUint16(data[dstport:dstport+2], newIP.Port())
-		recalcTCPv4Checksum(data, oldIP, newIP)
-	}
-}
-
-func (f *Firewall) findUsableSNATPort(fp *firewall.Packet, c *conn) error {
-	const halfThePorts = 0x7fff
-	oldPort := fp.RemotePort
-	conntrack := f.Conntrack
-	conntrack.Lock()
-	defer conntrack.Unlock()
-	for numPortsChecked := 0; numPortsChecked < halfThePorts; numPortsChecked++ {
-		_, ok := conntrack.Conns[*fp]
-		if !ok {
-			//yay, we can use this port
-			//track the snatted flow with the same expiration as the unsnatted version
-			c.snat.SnatPort = fp.RemotePort
-			conntrack.Conns[*fp] = c
-			return nil
-		}
-		//increment and retry. There's probably better strategies out there
-		fp.RemotePort++
-		if fp.RemotePort < halfThePorts {
-			fp.RemotePort += halfThePorts // keep it ephemeral for now
-		}
-	}
-
-	//if we made it here, we failed
-	fp.RemotePort = oldPort
-	return ErrCannotSNAT
-}
-
-func (f *Firewall) applySnat(data []byte, fp *firewall.Packet, c *conn, hostinfo *HostInfo) error {
-	if !f.snatAddr.IsValid() {
-		return ErrCannotSNAT
-	}
-	if f.snatAddr == fp.LocalAddr { //a packet that came from UDP (incoming) should never ever have our snat address on it
-		return ErrSNATAddressCollision
-	}
-	if c.snat.Valid() {
-		//old flow: make sure it came from the right place
-		if !slices.Contains(hostinfo.vpnAddrs, c.snat.SrcVpnIp) {
-			return ErrSNATIdentityMismatch
-		}
-		fp.RemoteAddr = f.snatAddr
-		fp.RemotePort = c.snat.SnatPort
-	} else if hostinfo.vpnAddrs[0].Is6() {
-		//we got a new flow
-		c.snat = &snatInfo{
-			Src:      netip.AddrPortFrom(fp.RemoteAddr, fp.RemotePort),
-			SrcVpnIp: hostinfo.vpnAddrs[0],
-		}
-		fp.RemoteAddr = f.snatAddr
-		//find a new port to use, if needed
-		err := f.findUsableSNATPort(fp, c)
-		if err != nil {
-			c.snat = nil
-			return err
-		}
-	} else {
-		return ErrCannotSNAT
-	}
-
-	newIP := netip.AddrPortFrom(f.snatAddr, c.snat.SnatPort)
-	rewritePacket(data, fp, c.snat.Src, newIP, ipv4SourcePosition, sourcePortOffset)
-	return nil
-}
-
-func (f *Firewall) identifyRemoteNetworkType(h *HostInfo, fp firewall.Packet) NetworkType {
-	if h.networks == nil {
-		// Simple case: Certificate has one address and no unsafe networks
-		if h.vpnAddrs[0] == fp.RemoteAddr {
-			return NetworkTypeVPN
-		} //else, fallthrough
-	} else if nwType, ok := h.networks.Lookup(fp.RemoteAddr); ok {
-		return nwType //will return NetworkTypeVPN or NetworkTypeUnsafe
-	}
-
-	//RemoteAddr not in our networks table
-	if f.snatAddr.IsValid() && fp.IsIPv4() && h.HasOnlyV6Addresses() {
-		return NetworkTypeUnverifiedSNATPeer
-	} else {
-		return NetworkTypeInvalidPeer
-	}
-}
-
-func (f *Firewall) allowRemoteNetworkType(nwType NetworkType, fp firewall.Packet) error {
-	switch nwType {
-	case NetworkTypeVPN:
-		return nil
-	case NetworkTypeInvalidPeer:
-		return ErrInvalidRemoteIP
-	case NetworkTypeVPNPeer:
-		//one day we might need a specialSnatMode case in here to handle routers with v4 addresses when we don't also have a v4 address?
-		return ErrPeerRejected // reject for now, one day this may have different FW rules
-	case NetworkTypeUnsafe:
-		return nil // nothing special, one day this may have different FW rules
-	case NetworkTypeUnverifiedSNATPeer:
-		if f.unsafeIPv4Origin.IsValid() && fp.LocalAddr == f.unsafeIPv4Origin {
-			return nil //the client case
-		}
-		if f.snatAddr.IsValid() {
-			if fp.RemoteAddr == f.snatAddr {
-				return ErrInvalidRemoteIP //we should never get a packet with our SNAT addr as the destination, or "from" our SNAT addr
-			}
-			return nil
-		} else {
-			return ErrInvalidRemoteIP
-		}
-	default:
-		return ErrUnknownNetworkType //should never happen
-	}
-}
-
-func (f *Firewall) willingToHandleLocalAddr(incoming bool, fp firewall.Packet, remoteNwType NetworkType) error {
-	if f.routableNetworks.Contains(fp.LocalAddr) {
-		return nil //easy, this should handle NetworkTypeVPN in all cases, and NetworkTypeUnsafe on the router side
-	}
-	if incoming { //at least for now, reject all traffic other than what we've already decided is locally routable
-		return ErrInvalidLocalIP
-	}
-
-	//below this line, all traffic is outgoing. Outgoing traffic to NetworkTypeUnsafe is not required to be considered inbound-routable
-	if remoteNwType == NetworkTypeUnsafe {
-		return nil
-	}
-
-	return ErrInvalidLocalIP
-}
-
 // Drop returns an error if the packet should be dropped, explaining why. It
 // returns nil if the packet should not be dropped.
-func (f *Firewall) Drop(fp firewall.Packet, pkt []byte, incoming bool, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) error {
+func (f *Firewall) Drop(fp firewall.Packet, incoming bool, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) error {
-	table := f.OutRules
-	if incoming {
-		table = f.InRules
-	}
-
-	snatmode := fp.IsIPv4() && h.HasOnlyV6Addresses() && f.snatAddr.IsValid()
-	if snatmode {
-		//if this is an IPv4 packet from a V6 only host, and we're configured to snat that kind of traffic, it must be snatted,
-		//so it can never be in the localcache, which lacks SNAT data
-		//nil out the pointer to avoid ever using it
-		localCache = nil
-	}
-
 	// Check if we spoke to this tuple, if we did then allow this packet
-	if localCache != nil {
+	if f.inConns(fp, h, caPool, localCache) {
-		if _, ok := localCache[fp]; ok {
-			return nil //packet matched the cache, we're not snatting, we can return early
-		}
-	}
-	c := f.inConns(fp, h, caPool, localCache)
-	if c != nil {
-		if incoming && snatmode {
-			return f.applySnat(pkt, &fp, c, h)
-		}
 		return nil
 	}
 
 	// Make sure remote address matches nebula certificate, and determine how to treat it
-	remoteNetworkType := f.identifyRemoteNetworkType(h, fp)
+	if h.networks == nil {
-	if err := f.allowRemoteNetworkType(remoteNetworkType, fp); err != nil {
+		// Simple case: Certificate has one address and no unsafe networks
-		f.metrics(incoming).droppedRemoteAddr.Inc(1)
+		if h.vpnAddrs[0] != fp.RemoteAddr {
-		return err
+			f.metrics(incoming).droppedRemoteAddr.Inc(1)
+			return ErrInvalidRemoteIP
+		}
+	} else {
+		nwType, ok := h.networks.Lookup(fp.RemoteAddr)
+		if !ok {
+			f.metrics(incoming).droppedRemoteAddr.Inc(1)
+			return ErrInvalidRemoteIP
+		}
+		switch nwType {
+		case NetworkTypeVPN:
+			break // nothing special
+		case NetworkTypeVPNPeer:
+			f.metrics(incoming).droppedRemoteAddr.Inc(1)
+			return ErrPeerRejected // reject for now, one day this may have different FW rules
+		case NetworkTypeUnsafe:
+			break // nothing special, one day this may have different FW rules
+		default:
+			f.metrics(incoming).droppedRemoteAddr.Inc(1)
+			return ErrUnknownNetworkType //should never happen
+		}
 	}
 
 	// Make sure we are supposed to be handling this local ip address
-	if err := f.willingToHandleLocalAddr(incoming, fp, remoteNetworkType); err != nil {
+	if !f.routableNetworks.Contains(fp.LocalAddr) {
 		f.metrics(incoming).droppedLocalAddr.Inc(1)
-		return err
+		return ErrInvalidLocalIP
+	}
+
+	table := f.OutRules
+	if incoming {
+		table = f.InRules
 	}
 
 	// We now know which firewall table to check against
@@ -666,14 +467,9 @@ func (f *Firewall) Drop(fp firewall.Packet, pkt []byte, incoming bool, h *HostIn
 	}
 
 	// We always want to conntrack since it is a faster operation
-	c = f.addConn(fp, incoming)
+	f.addConn(fp, incoming)
 
-	if incoming && remoteNetworkType == NetworkTypeUnverifiedSNATPeer {
+	return nil
-		return f.applySnat(pkt, &fp, c, h)
-	} else {
-		//outgoing snat is handled before this function is called
-		return nil
-	}
 }
 
 func (f *Firewall) metrics(incoming bool) firewallMetrics {
@@ -700,14 +496,12 @@ func (f *Firewall) EmitStats() {
 	metrics.GetOrRegisterGauge("firewall.rules.hash", nil).Update(int64(f.GetRuleHashFNV()))
 }
 
-func (f *Firewall) peek(fp firewall.Packet) *conn {
+func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) bool {
-	f.Conntrack.Lock()
+	if localCache != nil {
-	c := f.Conntrack.Conns[fp]
+		if _, ok := localCache[fp]; ok {
-	f.Conntrack.Unlock()
+			return true
-	return c
+		}
-}
+	}
-
-func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) *conn {
 	conntrack := f.Conntrack
 	conntrack.Lock()
 
@@ -721,7 +515,7 @@ func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool,
 
 	if !ok {
 		conntrack.Unlock()
-		return nil
+		return false
 	}
 
 	if c.rulesVersion != f.rulesVersion {
@@ -744,7 +538,7 @@ func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool,
 			}
 			delete(conntrack.Conns, fp)
 			conntrack.Unlock()
-			return nil
+			return false
 		}
 
 		if f.l.Level >= logrus.DebugLevel {
@@ -774,11 +568,12 @@ func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool,
 		localCache[fp] = struct{}{}
 	}
 
-	return c
+	return true
 }
 
-func (f *Firewall) packetTimeout(fp firewall.Packet) time.Duration {
+func (f *Firewall) addConn(fp firewall.Packet, incoming bool) {
 	var timeout time.Duration
+	c := &conn{}
 
 	switch fp.Protocol {
 	case firewall.ProtoTCP:
@@ -788,13 +583,7 @@ func (f *Firewall) packetTimeout(fp firewall.Packet) time.Duration {
 	default:
 		timeout = f.DefaultTimeout
 	}
-	return timeout
-}
 
-func (f *Firewall) addConn(fp firewall.Packet, incoming bool) *conn {
-	c := &conn{}
-
-	timeout := f.packetTimeout(fp)
 	conntrack := f.Conntrack
 	conntrack.Lock()
 	if _, ok := conntrack.Conns[fp]; !ok {
@@ -808,9 +597,7 @@ func (f *Firewall) addConn(fp firewall.Packet, incoming bool) *conn {
 	c.rulesVersion = f.rulesVersion
 	c.Expires = time.Now().Add(timeout)
 	conntrack.Conns[fp] = c
-
 	conntrack.Unlock()
-	return c
 }
 
 // Evict checks if a conntrack entry has expired, if so it is removed, if not it is re-added to the wheel

firewall/packet.go

@@ -31,10 +31,6 @@ type Packet struct {
 	Fragment   bool
 }
 
-func (fp *Packet) IsIPv4() bool {
-	return fp.LocalAddr.Is4() && fp.RemoteAddr.Is4()
-}
-
 func (fp *Packet) Copy() *Packet {
 	return &Packet{
 		LocalAddr:  fp.LocalAddr,

firewall_test.go

@@ -213,44 +213,44 @@ func TestFirewall_Drop(t *testing.T) {
 	cp := cert.NewCAPool()
 
 	// Drop outbound
-	assert.Equal(t, ErrNoMatchingRule, fw.Drop(p, nil, false, &h, cp, nil))
+	assert.Equal(t, ErrNoMatchingRule, fw.Drop(p, false, &h, cp, nil))
 	// Allow inbound
 	resetConntrack(fw)
-	require.NoError(t, fw.Drop(p, nil, true, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h, cp, nil))
 	// Allow outbound because conntrack
-	require.NoError(t, fw.Drop(p, nil, false, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, false, &h, cp, nil))
 
 	// test remote mismatch
 	oldRemote := p.RemoteAddr
 	p.RemoteAddr = netip.MustParseAddr("1.2.3.10")
-	assert.Equal(t, fw.Drop(p, nil, false, &h, cp, nil), ErrInvalidRemoteIP)
+	assert.Equal(t, fw.Drop(p, false, &h, cp, nil), ErrInvalidRemoteIP)
 	p.RemoteAddr = oldRemote
 
 	// ensure signer doesn't get in the way of group checks
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, &c)
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"nope"}, "", "", "", "", "signer-shasum"))
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"default-group"}, "", "", "", "", "signer-shasum-bad"))
-	assert.Equal(t, fw.Drop(p, nil, true, &h, cp, nil), ErrNoMatchingRule)
+	assert.Equal(t, fw.Drop(p, true, &h, cp, nil), ErrNoMatchingRule)
 
 	// test caSha doesn't drop on match
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, &c)
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"nope"}, "", "", "", "", "signer-shasum-bad"))
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"default-group"}, "", "", "", "", "signer-shasum"))
-	require.NoError(t, fw.Drop(p, nil, true, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h, cp, nil))
 
 	// ensure ca name doesn't get in the way of group checks
 	cp.CAs["signer-shasum"] = &cert.CachedCertificate{Certificate: &dummyCert{name: "ca-good"}}
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, &c)
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"nope"}, "", "", "", "ca-good", ""))
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"default-group"}, "", "", "", "ca-good-bad", ""))
-	assert.Equal(t, fw.Drop(p, nil, true, &h, cp, nil), ErrNoMatchingRule)
+	assert.Equal(t, fw.Drop(p, true, &h, cp, nil), ErrNoMatchingRule)
 
 	// test caName doesn't drop on match
 	cp.CAs["signer-shasum"] = &cert.CachedCertificate{Certificate: &dummyCert{name: "ca-good"}}
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, &c)
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"nope"}, "", "", "", "ca-good-bad", ""))
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"default-group"}, "", "", "", "ca-good", ""))
-	require.NoError(t, fw.Drop(p, nil, true, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h, cp, nil))
 }
 
 func TestFirewall_DropV6(t *testing.T) {
@@ -292,44 +292,44 @@ func TestFirewall_DropV6(t *testing.T) {
 	cp := cert.NewCAPool()
 
 	// Drop outbound
-	assert.Equal(t, ErrNoMatchingRule, fw.Drop(p, nil, false, &h, cp, nil))
+	assert.Equal(t, ErrNoMatchingRule, fw.Drop(p, false, &h, cp, nil))
 	// Allow inbound
 	resetConntrack(fw)
-	require.NoError(t, fw.Drop(p, nil, true, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h, cp, nil))
 	// Allow outbound because conntrack
-	require.NoError(t, fw.Drop(p, nil, false, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, false, &h, cp, nil))
 
 	// test remote mismatch
 	oldRemote := p.RemoteAddr
 	p.RemoteAddr = netip.MustParseAddr("fd12::56")
-	assert.Equal(t, fw.Drop(p, nil, false, &h, cp, nil), ErrInvalidRemoteIP)
+	assert.Equal(t, fw.Drop(p, false, &h, cp, nil), ErrInvalidRemoteIP)
 	p.RemoteAddr = oldRemote
 
 	// ensure signer doesn't get in the way of group checks
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, &c)
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"nope"}, "", "", "", "", "signer-shasum"))
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"default-group"}, "", "", "", "", "signer-shasum-bad"))
-	assert.Equal(t, fw.Drop(p, nil, true, &h, cp, nil), ErrNoMatchingRule)
+	assert.Equal(t, fw.Drop(p, true, &h, cp, nil), ErrNoMatchingRule)
 
 	// test caSha doesn't drop on match
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, &c)
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"nope"}, "", "", "", "", "signer-shasum-bad"))
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"default-group"}, "", "", "", "", "signer-shasum"))
-	require.NoError(t, fw.Drop(p, nil, true, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h, cp, nil))
 
 	// ensure ca name doesn't get in the way of group checks
 	cp.CAs["signer-shasum"] = &cert.CachedCertificate{Certificate: &dummyCert{name: "ca-good"}}
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, &c)
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"nope"}, "", "", "", "ca-good", ""))
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"default-group"}, "", "", "", "ca-good-bad", ""))
-	assert.Equal(t, fw.Drop(p, nil, true, &h, cp, nil), ErrNoMatchingRule)
+	assert.Equal(t, fw.Drop(p, true, &h, cp, nil), ErrNoMatchingRule)
 
 	// test caName doesn't drop on match
 	cp.CAs["signer-shasum"] = &cert.CachedCertificate{Certificate: &dummyCert{name: "ca-good"}}
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, &c)
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"nope"}, "", "", "", "ca-good-bad", ""))
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"default-group"}, "", "", "", "ca-good", ""))
-	require.NoError(t, fw.Drop(p, nil, true, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h, cp, nil))
 }
 
 func BenchmarkFirewallTable_match(b *testing.B) {
@@ -537,10 +537,10 @@ func TestFirewall_Drop2(t *testing.T) {
 	cp := cert.NewCAPool()
 
 	// h1/c1 lacks the proper groups
-	require.ErrorIs(t, fw.Drop(p, nil, true, &h1, cp, nil), ErrNoMatchingRule)
+	require.ErrorIs(t, fw.Drop(p, true, &h1, cp, nil), ErrNoMatchingRule)
 	// c has the proper groups
 	resetConntrack(fw)
-	require.NoError(t, fw.Drop(p, nil, true, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h, cp, nil))
 }
 
 func TestFirewall_Drop3(t *testing.T) {
@@ -618,18 +618,18 @@ func TestFirewall_Drop3(t *testing.T) {
 	cp := cert.NewCAPool()
 
 	// c1 should pass because host match
-	require.NoError(t, fw.Drop(p, nil, true, &h1, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h1, cp, nil))
 	// c2 should pass because ca sha match
 	resetConntrack(fw)
-	require.NoError(t, fw.Drop(p, nil, true, &h2, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h2, cp, nil))
 	// c3 should fail because no match
 	resetConntrack(fw)
-	assert.Equal(t, fw.Drop(p, nil, true, &h3, cp, nil), ErrNoMatchingRule)
+	assert.Equal(t, fw.Drop(p, true, &h3, cp, nil), ErrNoMatchingRule)
 
 	// Test a remote address match
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, c.Certificate)
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 1, 1, []string{}, "", "1.2.3.4/24", "", "", ""))
-	require.NoError(t, fw.Drop(p, nil, true, &h1, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h1, cp, nil))
 }
 
 func TestFirewall_Drop3V6(t *testing.T) {
@@ -667,7 +667,7 @@ func TestFirewall_Drop3V6(t *testing.T) {
 	fw := NewFirewall(l, time.Second, time.Minute, time.Hour, c.Certificate)
 	cp := cert.NewCAPool()
 	require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 1, 1, []string{}, "", "fd12::34/120", "", "", ""))
-	require.NoError(t, fw.Drop(p, nil, true, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h, cp, nil))
 }
 
 func TestFirewall_DropConntrackReload(t *testing.T) {
@@ -709,12 +709,12 @@ func TestFirewall_DropConntrackReload(t *testing.T) {
 	cp := cert.NewCAPool()
 
 	// Drop outbound
-	assert.Equal(t, fw.Drop(p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+	assert.Equal(t, fw.Drop(p, false, &h, cp, nil), ErrNoMatchingRule)
 	// Allow inbound
 	resetConntrack(fw)
-	require.NoError(t, fw.Drop(p, nil, true, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, true, &h, cp, nil))
 	// Allow outbound because conntrack
-	require.NoError(t, fw.Drop(p, nil, false, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, false, &h, cp, nil))
 
 	oldFw := fw
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, c.Certificate)
@@ -723,7 +723,7 @@ func TestFirewall_DropConntrackReload(t *testing.T) {
 	fw.rulesVersion = oldFw.rulesVersion + 1
 
 	// Allow outbound because conntrack and new rules allow port 10
-	require.NoError(t, fw.Drop(p, nil, false, &h, cp, nil))
+	require.NoError(t, fw.Drop(p, false, &h, cp, nil))
 
 	oldFw = fw
 	fw = NewFirewall(l, time.Second, time.Minute, time.Hour, c.Certificate)
@@ -732,7 +732,7 @@ func TestFirewall_DropConntrackReload(t *testing.T) {
 	fw.rulesVersion = oldFw.rulesVersion + 1
 
 	// Drop outbound because conntrack doesn't match new ruleset
-	assert.Equal(t, fw.Drop(p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+	assert.Equal(t, fw.Drop(p, false, &h, cp, nil), ErrNoMatchingRule)
 }
 
 func TestFirewall_ICMPPortBehavior(t *testing.T) {
@@ -778,12 +778,12 @@ func TestFirewall_ICMPPortBehavior(t *testing.T) {
 			p.LocalPort = 0
 			p.RemotePort = 0
 			// Drop outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 			// Allow inbound
 			resetConntrack(fw)
-			require.NoError(t, fw.Drop(*p, nil, true, &h, cp, nil))
+			require.NoError(t, fw.Drop(*p, true, &h, cp, nil))
 			//now also allow outbound
-			require.NoError(t, fw.Drop(*p, nil, false, &h, cp, nil))
+			require.NoError(t, fw.Drop(*p, false, &h, cp, nil))
 		})
 
 		t.Run("nonzero ports", func(t *testing.T) {
@@ -791,12 +791,12 @@ func TestFirewall_ICMPPortBehavior(t *testing.T) {
 			p.LocalPort = 0xabcd
 			p.RemotePort = 0x1234
 			// Drop outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 			// Allow inbound
 			resetConntrack(fw)
-			require.NoError(t, fw.Drop(*p, nil, true, &h, cp, nil))
+			require.NoError(t, fw.Drop(*p, true, &h, cp, nil))
 			//now also allow outbound
-			require.NoError(t, fw.Drop(*p, nil, false, &h, cp, nil))
+			require.NoError(t, fw.Drop(*p, false, &h, cp, nil))
 		})
 	})
 
@@ -808,12 +808,12 @@ func TestFirewall_ICMPPortBehavior(t *testing.T) {
 			p.LocalPort = 0
 			p.RemotePort = 0
 			// Drop outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 			// Allow inbound
 			resetConntrack(fw)
-			assert.Equal(t, fw.Drop(*p, nil, true, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, true, &h, cp, nil), ErrNoMatchingRule)
 			//now also allow outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 		})
 
 		t.Run("nonzero ports, still blocked", func(t *testing.T) {
@@ -821,12 +821,12 @@ func TestFirewall_ICMPPortBehavior(t *testing.T) {
 			p.LocalPort = 0xabcd
 			p.RemotePort = 0x1234
 			// Drop outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 			// Allow inbound
 			resetConntrack(fw)
-			assert.Equal(t, fw.Drop(*p, nil, true, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, true, &h, cp, nil), ErrNoMatchingRule)
 			//now also allow outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 		})
 
 		t.Run("nonzero, matching ports, still blocked", func(t *testing.T) {
@@ -834,12 +834,12 @@ func TestFirewall_ICMPPortBehavior(t *testing.T) {
 			p.LocalPort = 80
 			p.RemotePort = 80
 			// Drop outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 			// Allow inbound
 			resetConntrack(fw)
-			assert.Equal(t, fw.Drop(*p, nil, true, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, true, &h, cp, nil), ErrNoMatchingRule)
 			//now also allow outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 		})
 	})
 	t.Run("Any proto, any port", func(t *testing.T) {
@@ -851,12 +851,12 @@ func TestFirewall_ICMPPortBehavior(t *testing.T) {
 			p.LocalPort = 0
 			p.RemotePort = 0
 			// Drop outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 			// Allow inbound
 			resetConntrack(fw)
-			require.NoError(t, fw.Drop(*p, nil, true, &h, cp, nil))
+			require.NoError(t, fw.Drop(*p, true, &h, cp, nil))
 			//now also allow outbound
-			require.NoError(t, fw.Drop(*p, nil, false, &h, cp, nil))
+			require.NoError(t, fw.Drop(*p, false, &h, cp, nil))
 		})
 
 		t.Run("nonzero ports, allowed", func(t *testing.T) {
@@ -865,15 +865,15 @@ func TestFirewall_ICMPPortBehavior(t *testing.T) {
 			p.LocalPort = 0xabcd
 			p.RemotePort = 0x1234
 			// Drop outbound
-			assert.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			assert.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 			// Allow inbound
 			resetConntrack(fw)
-			require.NoError(t, fw.Drop(*p, nil, true, &h, cp, nil))
+			require.NoError(t, fw.Drop(*p, true, &h, cp, nil))
 			//now also allow outbound
-			require.NoError(t, fw.Drop(*p, nil, false, &h, cp, nil))
+			require.NoError(t, fw.Drop(*p, false, &h, cp, nil))
 			//different ID is blocked
 			p.RemotePort++
-			require.Equal(t, fw.Drop(*p, nil, false, &h, cp, nil), ErrNoMatchingRule)
+			require.Equal(t, fw.Drop(*p, false, &h, cp, nil), ErrNoMatchingRule)
 		})
 	})
 
@@ -922,7 +922,7 @@ func TestFirewall_DropIPSpoofing(t *testing.T) {
 		Protocol:   firewall.ProtoUDP,
 		Fragment:   false,
 	}
-	assert.Equal(t, fw.Drop(p, nil, true, &h1, cp, nil), ErrInvalidRemoteIP)
+	assert.Equal(t, fw.Drop(p, true, &h1, cp, nil), ErrInvalidRemoteIP)
 }
 
 func BenchmarkLookup(b *testing.B) {
@@ -1042,7 +1042,7 @@ func TestNewFirewallFromConfig(t *testing.T) {
 	l := test.NewLogger()
 	// Test a bad rule definition
 	c := &dummyCert{}
-	cs, err := newCertState(l, cert.Version2, nil, c, false, cert.Curve_CURVE25519, nil)
+	cs, err := newCertState(cert.Version2, nil, c, false, cert.Curve_CURVE25519, nil)
 	require.NoError(t, err)
 
 	conf := config.NewC(l)
@@ -1336,7 +1336,7 @@ func (c *testcase) Test(t *testing.T, fw *Firewall) {
 	t.Helper()
 	cp := cert.NewCAPool()
 	resetConntrack(fw)
-	err := fw.Drop(c.p, nil, true, c.h, cp, nil)
+	err := fw.Drop(c.p, true, c.h, cp, nil)
 	if c.err == nil {
 		require.NoError(t, err, "failed to not drop remote address %s", c.p.RemoteAddr)
 	} else {
@@ -1344,7 +1344,7 @@ func (c *testcase) Test(t *testing.T, fw *Firewall) {
 	}
 }
 
-func buildHostinfo(setup testsetup, theirPrefixes ...netip.Prefix) *HostInfo {
+func buildTestCase(setup testsetup, err error, theirPrefixes ...netip.Prefix) testcase {
 	c1 := dummyCert{
 		name:     "host1",
 		networks: theirPrefixes,
@@ -1364,11 +1364,6 @@ func buildHostinfo(setup testsetup, theirPrefixes ...netip.Prefix) *HostInfo {
 		h.vpnAddrs[i] = theirPrefixes[i].Addr()
 	}
 	h.buildNetworks(setup.myVpnNetworksTable, &c1)
-	return &h
-}
-
-func buildTestCase(setup testsetup, err error, theirPrefixes ...netip.Prefix) testcase {
-	h := buildHostinfo(setup, theirPrefixes...)
 	p := firewall.Packet{
 		LocalAddr:  setup.c.Networks()[0].Addr(), //todo?
 		RemoteAddr: theirPrefixes[0].Addr(),
@@ -1378,9 +1373,9 @@ func buildTestCase(setup testsetup, err error, theirPrefixes ...netip.Prefix) te
 		Fragment:   false,
 	}
 	return testcase{
-		h:   h,
+		h:   &h,
 		p:   p,
-		c:   h.ConnectionState.peerCert.Certificate,
+		c:   &c1,
 		err: err,
 	}
 }
@@ -1402,19 +1397,6 @@ func newSetup(t *testing.T, l *logrus.Logger, myPrefixes ...netip.Prefix) testse
 	return newSetupFromCert(t, l, c)
 }
 
-func newSnatSetup(t *testing.T, l *logrus.Logger, myPrefix netip.Prefix, snatAddr netip.Addr) testsetup {
-	c := dummyCert{
-		name:     "me",
-		networks: []netip.Prefix{myPrefix},
-		groups:   []string{"default-group"},
-		issuer:   "signer-shasum",
-	}
-
-	out := newSetupFromCert(t, l, c)
-	out.fw.snatAddr = snatAddr
-	return out
-}
-
 func newSetupFromCert(t *testing.T, l *logrus.Logger, c dummyCert) testsetup {
 	myVpnNetworksTable := new(bart.Lite)
 	for _, prefix := range c.Networks() {
@@ -1550,59 +1532,3 @@ func resetConntrack(fw *Firewall) {
 	fw.Conntrack.Conns = map[firewall.Packet]*conn{}
 	fw.Conntrack.Unlock()
 }
-
-func TestFirewall_SNAT(t *testing.T) {
-	t.Parallel()
-	l := test.NewLogger()
-	ob := &bytes.Buffer{}
-	l.SetOutput(ob)
-	cp := cert.NewCAPool()
-	myPrefix := netip.MustParsePrefix("1.1.1.1/8")
-
-	MyCert := dummyCert{
-		name:     "me",
-		networks: []netip.Prefix{myPrefix},
-		groups:   []string{"default-group"},
-		issuer:   "signer-shasum",
-	}
-
-	theirPrefix := netip.MustParsePrefix("1.2.2.2/8")
-	snatAddr := netip.MustParseAddr("169.254.55.96")
-	t.Run("allow inbound all matching", func(t *testing.T) {
-		t.Parallel()
-		myCert := MyCert.Copy()
-		setup := newSnatSetup(t, l, myPrefix, snatAddr)
-		fw := NewFirewall(l, time.Second, time.Minute, time.Hour, myCert)
-		require.NoError(t, fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"any"}, "", "", "", "", ""))
-		resetConntrack(setup.fw)
-		h := buildHostinfo(setup, theirPrefix)
-		p := firewall.Packet{
-			LocalAddr:  setup.c.Networks()[0].Addr(), //todo?
-			RemoteAddr: h.vpnAddrs[0],
-			LocalPort:  10,
-			RemotePort: 90,
-			Protocol:   firewall.ProtoUDP,
-			Fragment:   false,
-		}
-		require.NoError(t, setup.fw.Drop(p, nil, true, h, cp, nil))
-	})
-	//t.Run("allow inbound unsafe route", func(t *testing.T) {
-	//	t.Parallel()
-	//	unsafePrefix := netip.MustParsePrefix("192.168.0.0/24")
-	//	c := dummyCert{
-	//		name:           "me",
-	//		networks:       []netip.Prefix{myPrefix},
-	//		unsafeNetworks: []netip.Prefix{unsafePrefix},
-	//		groups:         []string{"default-group"},
-	//		issuer:         "signer-shasum",
-	//	}
-	//	unsafeSetup := newSetupFromCert(t, l, c)
-	//	tc := buildTestCase(unsafeSetup, nil, twoPrefixes...)
-	//	tc.p.LocalAddr = netip.MustParseAddr("192.168.0.3")
-	//	tc.err = ErrNoMatchingRule
-	//	tc.Test(t, unsafeSetup.fw) //should hit firewall and bounce off
-	//	require.NoError(t, unsafeSetup.fw.AddRule(true, firewall.ProtoAny, 0, 0, []string{"any"}, "", "", unsafePrefix.String(), "", ""))
-	//	tc.err = nil
-	//	tc.Test(t, unsafeSetup.fw) //should pass
-	//})
-}

handshake_manager.go

@@ -23,22 +23,25 @@ const (
 	DefaultHandshakeRetries       = 10
 	DefaultHandshakeTriggerBuffer = 64
 	DefaultUseRelays              = true
+	DefaultMaxHandshakeRate       = 0 // 0 means unlimited
 )
 
 var (
 	defaultHandshakeConfig = HandshakeConfig{
-		tryInterval:   DefaultHandshakeTryInterval,
+		tryInterval:      DefaultHandshakeTryInterval,
-		retries:       DefaultHandshakeRetries,
+		retries:          DefaultHandshakeRetries,
-		triggerBuffer: DefaultHandshakeTriggerBuffer,
+		triggerBuffer:    DefaultHandshakeTriggerBuffer,
-		useRelays:     DefaultUseRelays,
+		useRelays:        DefaultUseRelays,
+		maxHandshakeRate: DefaultMaxHandshakeRate,
 	}
 )
 
 type HandshakeConfig struct {
-	tryInterval   time.Duration
+	tryInterval      time.Duration
-	retries       int64
+	retries          int64
-	triggerBuffer int
+	triggerBuffer    int
-	useRelays     bool
+	useRelays        bool
+	maxHandshakeRate int
 
 	messageMetrics *MessageMetrics
 }
@@ -58,9 +61,15 @@ type HandshakeManager struct {
 	messageMetrics         *MessageMetrics
 	metricInitiated        metrics.Counter
 	metricTimedOut         metrics.Counter
+	metricRateLimited      metrics.Counter
 	f                      *Interface
 	l                      *logrus.Logger
 
+	// Rate limiting for new handshakes (token bucket)
+	rateBucket   int // tokens currently available
+	rateMax      int // max tokens (== max handshakes per second), 0 means unlimited
+	rateLastTick time.Time
+
 	// can be used to trigger outbound handshake for the given vpnIp
 	trigger chan netip.Addr
 }
@@ -116,10 +125,41 @@ func NewHandshakeManager(l *logrus.Logger, mainHostMap *HostMap, lightHouse *Lig
 		messageMetrics:         config.messageMetrics,
 		metricInitiated:        metrics.GetOrRegisterCounter("handshake_manager.initiated", nil),
 		metricTimedOut:         metrics.GetOrRegisterCounter("handshake_manager.timed_out", nil),
+		metricRateLimited:      metrics.GetOrRegisterCounter("handshake_manager.rate_limited", nil),
+		rateBucket:             config.maxHandshakeRate,
+		rateMax:                config.maxHandshakeRate,
+		rateLastTick:           time.Now(),
 		l:                      l,
 	}
 }
 
+// handshakeRateAllow checks the token bucket rate limiter and returns true if a
+// new handshake is allowed. Must be called with hm.Lock held.
+func (hm *HandshakeManager) handshakeRateAllow(now time.Time) bool {
+	if hm.rateMax == 0 {
+		return true
+	}
+
+	// Refill tokens based on elapsed time
+	elapsed := now.Sub(hm.rateLastTick)
+	if elapsed >= time.Second {
+		// Add tokens for full seconds elapsed
+		tokens := int(elapsed/time.Second) * hm.rateMax
+		hm.rateBucket += tokens
+		if hm.rateBucket > hm.rateMax {
+			hm.rateBucket = hm.rateMax
+		}
+		hm.rateLastTick = now
+	}
+
+	if hm.rateBucket > 0 {
+		hm.rateBucket--
+		return true
+	}
+
+	return false
+}
+
 func (hm *HandshakeManager) Run(ctx context.Context) {
 	clockSource := time.NewTicker(hm.config.tryInterval)
 	defer clockSource.Stop()
@@ -149,6 +189,15 @@ func (hm *HandshakeManager) HandleIncoming(via ViaSender, packet []byte, h *head
 	case header.HandshakeIXPSK0:
 		switch h.MessageCounter {
 		case 1:
+			// Check rate limit for new incoming handshakes
+			hm.Lock()
+			allowed := hm.handshakeRateAllow(time.Now())
+			hm.Unlock()
+			if !allowed {
+				hm.metricRateLimited.Inc(1)
+				hm.l.WithField("from", via).Debug("Handshake rate limit reached, dropping incoming handshake")
+				return
+			}
 			ixHandshakeStage1(hm.f, via, packet, h)
 
 		case 2:

handshake_manager_test.go

@@ -65,6 +65,68 @@ func Test_NewHandshakeManagerVpnIp(t *testing.T) {
 	assert.NotContains(t, blah.vpnIps, ip)
 }
 
+func Test_HandshakeManagerRateLimit(t *testing.T) {
+	l := test.NewLogger()
+	localrange := netip.MustParsePrefix("10.1.1.1/24")
+	preferredRanges := []netip.Prefix{localrange}
+	mainHM := newHostMap(l)
+	mainHM.preferredRanges.Store(&preferredRanges)
+
+	lh := newTestLighthouse()
+
+	config := defaultHandshakeConfig
+	config.maxHandshakeRate = 2
+
+	hm := NewHandshakeManager(l, mainHM, lh, &udp.NoopConn{}, config)
+	hm.f = &Interface{handshakeManager: hm, pki: &PKI{}, l: l}
+
+	now := time.Now()
+
+	// Should allow up to maxHandshakeRate handshakes
+	hm.Lock()
+	assert.True(t, hm.handshakeRateAllow(now), "first handshake should be allowed")
+	assert.True(t, hm.handshakeRateAllow(now), "second handshake should be allowed")
+	assert.False(t, hm.handshakeRateAllow(now), "third handshake should be rate limited")
+	hm.Unlock()
+
+	// After advancing time by 1 second, tokens should refill
+	hm.Lock()
+	assert.True(t, hm.handshakeRateAllow(now.Add(time.Second)), "handshake should be allowed after token refill")
+	hm.Unlock()
+}
+
+func Test_HandshakeManagerRateLimitUnlimited(t *testing.T) {
+	l := test.NewLogger()
+	localrange := netip.MustParsePrefix("10.1.1.1/24")
+	preferredRanges := []netip.Prefix{localrange}
+	mainHM := newHostMap(l)
+	mainHM.preferredRanges.Store(&preferredRanges)
+
+	lh := newTestLighthouse()
+
+	cs := &CertState{
+		initiatingVersion: cert.Version1,
+		privateKey:        []byte{},
+		v1Cert:            &dummyCert{version: cert.Version1},
+		v1HandshakeBytes:  []byte{},
+	}
+
+	// Default config has maxHandshakeRate=0 (unlimited)
+	hm := NewHandshakeManager(l, mainHM, lh, &udp.NoopConn{}, defaultHandshakeConfig)
+	hm.f = &Interface{handshakeManager: hm, pki: &PKI{}, l: l}
+	hm.f.pki.cs.Store(cs)
+
+	// Should allow many handshakes with no limit
+	// Limited to 10 due to test lighthouse query channel buffer
+	for i := 0; i < 10; i++ {
+		ip := netip.MustParseAddr("172.1.1.1").As16()
+		ip[15] = byte(i + 1)
+		addr := netip.AddrFrom16(ip)
+		h := hm.StartHandshake(addr, nil)
+		assert.NotNil(t, h, "handshake %d should be allowed with unlimited rate", i)
+	}
+}
+
 func testCountTimerWheelEntries(tw *LockingTimerWheel[netip.Addr]) (c int) {
 	for _, i := range tw.t.wheel {
 		n := i.Head

hostmap.go

@@ -224,9 +224,6 @@ const (
 	NetworkTypeVPNPeer
 	// NetworkTypeUnsafe is a network from Certificate.UnsafeNetworks()
 	NetworkTypeUnsafe
-	// NetworkTypeUnverifiedSNATPeer is used to indicate traffic we're willing to route, but never deliver to a NetworkTypeVPN
-	NetworkTypeUnverifiedSNATPeer
-	NetworkTypeInvalidPeer
 )
 
 type HostInfo struct {
@@ -280,15 +277,6 @@ type HostInfo struct {
 	lastUsed time.Time
 }
 
-func (i *HostInfo) HasOnlyV6Addresses() bool {
-	for _, vpnIp := range i.vpnAddrs {
-		if !vpnIp.Is6() {
-			return false
-		}
-	}
-	return true
-}
-
 type ViaSender struct {
 	UdpAddr   netip.AddrPort
 	relayHI   *HostInfo // relayHI is the host info object of the relay

inside.go

@@ -48,7 +48,9 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 		return
 	}
 
-	hostinfo, ready := f.getHostinfo(packet, fwPacket)
+	hostinfo, ready := f.getOrHandshakeConsiderRouting(fwPacket, func(hh *HandshakeHostInfo) {
+		hh.cachePacket(f.l, header.Message, 0, packet, f.sendMessageNow, f.cachedPacketMetrics)
+	})
 
 	if hostinfo == nil {
 		f.rejectInside(packet, out, q)
@@ -64,9 +66,10 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 		return
 	}
 
-	dropReason := f.firewall.Drop(*fwPacket, packet, false, hostinfo, f.pki.GetCAPool(), localCache)
+	dropReason := f.firewall.Drop(*fwPacket, false, hostinfo, f.pki.GetCAPool(), localCache)
 	if dropReason == nil {
 		f.sendNoMetrics(header.Message, 0, hostinfo.ConnectionState, hostinfo, netip.AddrPort{}, packet, nb, out, q)
+
 	} else {
 		f.rejectInside(packet, out, q)
 		if f.l.Level >= logrus.DebugLevel {
@@ -78,26 +81,6 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 	}
 }
 
-func (f *Interface) getHostinfo(packet []byte, fwPacket *firewall.Packet) (*HostInfo, bool) {
-	if f.firewall.ShouldUnSNAT(fwPacket) {
-		//unsnat packet re-writing also happens here, would be nice to not,
-		//but we need to do the unsnat lookup to find the hostinfo so we can run the firewall checks
-		destVpnAddr := f.firewall.unSnat(packet, fwPacket)
-		if destVpnAddr.IsValid() {
-			//because this was a snatted packet, we know it has an on-overlay destination, so no routing should be required.
-			return f.getOrHandshakeNoRouting(destVpnAddr, func(hh *HandshakeHostInfo) {
-				hh.cachePacket(f.l, header.Message, 0, packet, f.sendMessageNow, f.cachedPacketMetrics)
-			})
-		} else {
-			return nil, false
-		}
-	} else { //if we didn't need to unsnat
-		return f.getOrHandshakeConsiderRouting(fwPacket, func(hh *HandshakeHostInfo) {
-			hh.cachePacket(f.l, header.Message, 0, packet, f.sendMessageNow, f.cachedPacketMetrics)
-		})
-	}
-}
-
 func (f *Interface) rejectInside(packet []byte, out []byte, q int) {
 	if !f.firewall.InSendReject {
 		return
@@ -235,7 +218,7 @@ func (f *Interface) sendMessageNow(t header.MessageType, st header.MessageSubTyp
 	}
 
 	// check if packet is in outbound fw rules
-	dropReason := f.firewall.Drop(*fp, p, false, hostinfo, f.pki.GetCAPool(), nil)
+	dropReason := f.firewall.Drop(*fp, false, hostinfo, f.pki.GetCAPool(), nil)
 	if dropReason != nil {
 		if f.l.Level >= logrus.DebugLevel {
 			f.l.WithField("fwPacket", fp).

interface.go

@@ -248,7 +248,6 @@ func (f *Interface) activate() {
 		f.inside.Close()
 		f.l.Fatal(err)
 	}
-	f.firewall.SetSNATAddressFromInterface(f)
 }
 
 func (f *Interface) run() {
@@ -345,7 +344,6 @@ func (f *Interface) reloadFirewall(c *config.C) {
 		f.l.WithError(err).Error("Error while creating firewall during reload")
 		return
 	}
-	fw.SetSNATAddressFromInterface(f)
 
 	oldFw := f.firewall
 	conntrack := oldFw.Conntrack

main.go

@@ -131,8 +131,7 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 			deviceFactory = overlay.NewDeviceFromConfig
 		}
 
-		cs := pki.getCertState()
+		tun, err = deviceFactory(c, l, pki.getCertState().myVpnNetworks, routines)
-		tun, err = deviceFactory(c, l, cs.myVpnNetworks, cs.GetDefaultCertificate().UnsafeNetworks(), routines)
 		if err != nil {
 			return nil, util.ContextualizeIfNeeded("Failed to get a tun/tap device", err)
 		}
@@ -205,10 +204,11 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 	useRelays := c.GetBool("relay.use_relays", DefaultUseRelays) && !c.GetBool("relay.am_relay", false)
 
 	handshakeConfig := HandshakeConfig{
-		tryInterval:   c.GetDuration("handshakes.try_interval", DefaultHandshakeTryInterval),
+		tryInterval:      c.GetDuration("handshakes.try_interval", DefaultHandshakeTryInterval),
-		retries:       int64(c.GetInt("handshakes.retries", DefaultHandshakeRetries)),
+		retries:          int64(c.GetInt("handshakes.retries", DefaultHandshakeRetries)),
-		triggerBuffer: c.GetInt("handshakes.trigger_buffer", DefaultHandshakeTriggerBuffer),
+		triggerBuffer:    c.GetInt("handshakes.trigger_buffer", DefaultHandshakeTriggerBuffer),
-		useRelays:     useRelays,
+		useRelays:        useRelays,
+		maxHandshakeRate: c.GetInt("handshakes.max_rate", DefaultMaxHandshakeRate),
 
 		messageMetrics: messageMetrics,
 	}

outside.go

@@ -190,6 +190,13 @@ func (f *Interface) readOutsidePackets(via ViaSender, out []byte, packet []byte,
 		if !f.handleEncrypted(ci, via, h) {
 			return
 		}
+		_, err = f.decrypt(hostinfo, h.MessageCounter, out, packet, h, nb)
+		if err != nil {
+			hostinfo.logger(f.l).WithError(err).WithField("from", via).
+				WithField("packet", packet).
+				Error("Failed to decrypt CloseTunnel packet")
+			return
+		}
 
 		hostinfo.logger(f.l).WithField("from", via).
 			Info("Close tunnel received, tearing down.")
@@ -514,7 +521,7 @@ func (f *Interface) decryptToTun(hostinfo *HostInfo, messageCounter uint64, out
 		return false
 	}
 
-	dropReason := f.firewall.Drop(*fwPacket, out, true, hostinfo, f.pki.GetCAPool(), localCache)
+	dropReason := f.firewall.Drop(*fwPacket, true, hostinfo, f.pki.GetCAPool(), localCache)
 	if dropReason != nil {
 		// NOTE: We give `packet` as the `out` here since we already decrypted from it and we don't need it anymore
 		// This gives us a buffer to build the reject packet in

overlay/device.go

@@ -11,9 +11,6 @@ type Device interface {
 	io.ReadWriteCloser
 	Activate() error
 	Networks() []netip.Prefix
-	UnsafeNetworks() []netip.Prefix
-	UnsafeIPv4OriginAddress() netip.Prefix
-	SNATAddress() netip.Prefix
 	Name() string
 	RoutesFor(netip.Addr) routing.Gateways
 	SupportsMultiqueue() bool

overlay/tun.go

@@ -1,9 +1,7 @@
 package overlay
 
 import (
-	"crypto/rand"
 	"fmt"
-	"io"
 	"net"
 	"net/netip"
 
@@ -24,22 +22,22 @@ func (e *NameError) Error() string {
 }
 
 // TODO: We may be able to remove routines
-type DeviceFactory func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, routines int) (Device, error)
+type DeviceFactory func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error)
 
-func NewDeviceFromConfig(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, routines int) (Device, error) {
+func NewDeviceFromConfig(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error) {
 	switch {
 	case c.GetBool("tun.disabled", false):
 		tun := newDisabledTun(vpnNetworks, c.GetInt("tun.tx_queue", 500), c.GetBool("stats.message_metrics", false), l)
 		return tun, nil
 
 	default:
-		return newTun(c, l, vpnNetworks, unsafeNetworks, routines > 1)
+		return newTun(c, l, vpnNetworks, routines > 1)
 	}
 }
 
 func NewFdDeviceFromConfig(fd *int) DeviceFactory {
-	return func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, routines int) (Device, error) {
+	return func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error) {
-		return newTunFromFd(c, l, *fd, vpnNetworks, unsafeNetworks)
+		return newTunFromFd(c, l, *fd, vpnNetworks)
 	}
 }
 
@@ -131,85 +129,3 @@ func selectGateway(dest netip.Prefix, gateways []netip.Prefix) (netip.Prefix, er
 
 	return netip.Prefix{}, fmt.Errorf("no gateway found for %v in the list of vpn networks", dest)
 }
-
-// genLinkLocal generates a random IPv4 link-local address.
-// If randomizer is nil, it uses rand.Reader to find two random bytes
-func genLinkLocal(randomizer io.Reader) netip.Prefix {
-	if randomizer == nil {
-		randomizer = rand.Reader
-	}
-	octets := []byte{169, 254, 0, 0}
-	_, _ = randomizer.Read(octets[2:4])
-	return coerceLinkLocal(octets)
-}
-
-func coerceLinkLocal(octets []byte) netip.Prefix {
-	if octets[3] == 0 {
-		octets[3] = 1 //please no .0 addresses
-	} else if octets[2] == 255 && octets[3] == 255 {
-		octets[3] = 254 //please no broadcast addresses
-	}
-	out, _ := netip.AddrFromSlice(octets)
-	return netip.PrefixFrom(out, 32)
-}
-
-// prepareUnsafeOriginAddr provides the IPv4 address used on IPv6-only clients that need to access IPv4 unsafe routes
-func prepareUnsafeOriginAddr(d Device, l *logrus.Logger, c *config.C, routes []Route) netip.Prefix {
-	if !d.Networks()[0].Addr().Is6() {
-		return netip.Prefix{} //if we have an IPv4 assignment within the overlay, we don't need an unsafe origin address
-	}
-
-	needed := false
-	for _, route := range routes { //or if we have a route defined into an IPv4 range
-		if route.Cidr.Addr().Is4() {
-			needed = true //todo should this only apply to unsafe routes? almost certainly
-			break
-		}
-	}
-	if !needed {
-		return netip.Prefix{}
-	}
-
-	//todo better config name for sure
-	if a := c.GetString("tun.unsafe_origin_address_for_4over6", ""); a != "" {
-		out, err := netip.ParseAddr(a)
-		if err != nil {
-			l.WithField("value", a).WithError(err).Warn("failed to parse tun.unsafe_origin_address_for_4over6, will use a random value")
-		} else if !out.Is4() || !out.IsLinkLocalUnicast() {
-			l.WithField("value", out).Warn("tun.unsafe_origin_address_for_4over6 must be an IPv4 address")
-		} else if out.IsValid() {
-			return netip.PrefixFrom(out, 32)
-		}
-	}
-	return genLinkLocal(nil)
-}
-
-// prepareSnatAddr provides the address that an IPv6-only unsafe router should use to SNAT traffic before handing it to the operating system
-func prepareSnatAddr(d Device, l *logrus.Logger, c *config.C) netip.Prefix {
-	if !d.Networks()[0].Addr().Is6() {
-		return netip.Prefix{} //if we have an IPv4 assignment within the overlay, we don't need a snat address
-	}
-
-	needed := false
-	for _, un := range d.UnsafeNetworks() { //if we are an unsafe router for an IPv4 range
-		if un.Addr().Is4() {
-			needed = true
-			break
-		}
-	}
-	if !needed {
-		return netip.Prefix{}
-	}
-
-	if a := c.GetString("tun.snat_address_for_4over6", ""); a != "" {
-		out, err := netip.ParseAddr(a)
-		if err != nil {
-			l.WithField("value", a).WithError(err).Warn("failed to parse tun.snat_address_for_4over6, will use a random value")
-		} else if !out.Is4() || !out.IsLinkLocalUnicast() {
-			l.WithField("value", out).Warn("tun.snat_address_for_4over6 must be an IPv4 address")
-		} else if out.IsValid() {
-			return netip.PrefixFrom(out, 32)
-		}
-	}
-	return genLinkLocal(nil)
-}

overlay/tun_android.go

@@ -19,16 +19,14 @@ import (
 
 type tun struct {
 	io.ReadWriteCloser
-	fd               int
+	fd          int
-	vpnNetworks      []netip.Prefix
+	vpnNetworks []netip.Prefix
-	unsafeNetworks   []netip.Prefix
+	Routes      atomic.Pointer[[]Route]
-	unsafeIPv4Origin netip.Prefix
+	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
-	Routes           atomic.Pointer[[]Route]
+	l           *logrus.Logger
-	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
-	l                *logrus.Logger
 }
 
-func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix) (*tun, error) {
+func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
 	// XXX Android returns an fd in non-blocking mode which is necessary for shutdown to work properly.
 	// Be sure not to call file.Fd() as it will set the fd to blocking mode.
 	file := os.NewFile(uintptr(deviceFd), "/dev/net/tun")
@@ -37,7 +35,6 @@ func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []net
 		ReadWriteCloser: file,
 		fd:              deviceFd,
 		vpnNetworks:     vpnNetworks,
-		unsafeNetworks:  unsafeNetworks,
 		l:               l,
 	}
 
@@ -56,7 +53,7 @@ func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []net
 	return t, nil
 }
 
-func newTun(_ *config.C, _ *logrus.Logger, _ []netip.Prefix, _ []netip.Prefix, _ bool) (*tun, error) {
+func newTun(_ *config.C, _ *logrus.Logger, _ []netip.Prefix, _ bool) (*tun, error) {
 	return nil, fmt.Errorf("newTun not supported in Android")
 }
 
@@ -79,8 +76,6 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
-	t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
-
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -96,18 +91,6 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
-func (t *tun) UnsafeNetworks() []netip.Prefix {
-	return t.unsafeNetworks
-}
-
-func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return t.unsafeIPv4Origin
-}
-
-func (t *tun) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (t *tun) Name() string {
 	return "android"
 }

overlay/tun_darwin.go

@@ -24,15 +24,13 @@ import (
 
 type tun struct {
 	io.ReadWriteCloser
-	Device           string
+	Device      string
-	vpnNetworks      []netip.Prefix
+	vpnNetworks []netip.Prefix
-	unsafeNetworks   []netip.Prefix
+	DefaultMTU  int
-	unsafeIPv4Origin netip.Prefix
+	Routes      atomic.Pointer[[]Route]
-	DefaultMTU       int
+	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
-	Routes           atomic.Pointer[[]Route]
+	linkAddr    *netroute.LinkAddr
-	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
+	l           *logrus.Logger
-	linkAddr         *netroute.LinkAddr
-	l                *logrus.Logger
 
 	// cache out buffer since we need to prepend 4 bytes for tun metadata
 	out []byte
@@ -81,7 +79,7 @@ type ifreqAlias6 struct {
 	Lifetime   addrLifetime
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*tun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*tun, error) {
 	name := c.GetString("tun.dev", "")
 	ifIndex := -1
 	if name != "" && name != "utun" {
@@ -129,7 +127,6 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNet
 		ReadWriteCloser: os.NewFile(uintptr(fd), ""),
 		Device:          name,
 		vpnNetworks:     vpnNetworks,
-		unsafeNetworks:  unsafeNetworks,
 		DefaultMTU:      c.GetInt("tun.mtu", DefaultMTU),
 		l:               l,
 	}
@@ -156,7 +153,7 @@ func (t *tun) deviceBytes() (o [16]byte) {
 	return
 }
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*tun, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in Darwin")
 }
 
@@ -216,11 +213,6 @@ func (t *tun) Activate() error {
 			}
 		}
 	}
-	if t.unsafeIPv4Origin.IsValid() && t.unsafeIPv4Origin.Addr().Is4() {
-		if err = t.activate4(t.unsafeIPv4Origin); err != nil {
-			return err
-		}
-	}
 
 	// Run the interface
 	ifrf.Flags = ifrf.Flags | unix.IFF_UP | unix.IFF_RUNNING
@@ -322,10 +314,6 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
-	if initial {
-		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
-	}
-
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -557,18 +545,6 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
-func (t *tun) UnsafeNetworks() []netip.Prefix {
-	return t.unsafeNetworks
-}
-
-func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return t.unsafeIPv4Origin
-}
-
-func (t *tun) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (t *tun) Name() string {
 	return t.Device
 }

overlay/tun_disabled.go

@@ -52,17 +52,6 @@ func (t *disabledTun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
-func (*disabledTun) UnsafeNetworks() []netip.Prefix {
-	return nil
-}
-func (*disabledTun) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
-func (*disabledTun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (*disabledTun) Name() string {
 	return "disabled"
 }

overlay/tun_freebsd.go

@@ -86,16 +86,14 @@ type ifreqAlias6 struct {
 }
 
 type tun struct {
-	Device           string
+	Device      string
-	vpnNetworks      []netip.Prefix
+	vpnNetworks []netip.Prefix
-	unsafeNetworks   []netip.Prefix
+	MTU         int
-	unsafeIPv4Origin netip.Prefix
+	Routes      atomic.Pointer[[]Route]
-	MTU              int
+	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
-	Routes           atomic.Pointer[[]Route]
+	linkAddr    *netroute.LinkAddr
-	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
+	l           *logrus.Logger
-	linkAddr         *netroute.LinkAddr
+	devFd       int
-	l                *logrus.Logger
-	devFd            int
 }
 
 func (t *tun) Read(to []byte) (int, error) {
@@ -201,11 +199,11 @@ func (t *tun) Close() error {
 	return nil
 }
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*tun, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in FreeBSD")
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*tun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*tun, error) {
 	// Try to open existing tun device
 	var fd int
 	var err error
@@ -272,12 +270,11 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNet
 	}
 
 	t := &tun{
-		Device:         deviceName,
+		Device:      deviceName,
-		vpnNetworks:    vpnNetworks,
+		vpnNetworks: vpnNetworks,
-		unsafeNetworks: unsafeNetworks,
+		MTU:         c.GetInt("tun.mtu", DefaultMTU),
-		MTU:            c.GetInt("tun.mtu", DefaultMTU),
+		l:           l,
-		l:              l,
+		devFd:       fd,
-		devFd:          fd,
 	}
 
 	err = t.reload(c, true)
@@ -413,10 +410,6 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
-	if initial {
-		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
-	}
-
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -453,18 +446,6 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
-func (t *tun) UnsafeNetworks() []netip.Prefix {
-	return t.unsafeNetworks
-}
-
-func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return t.unsafeIPv4Origin
-}
-
-func (t *tun) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (t *tun) Name() string {
 	return t.Device
 }

overlay/tun_ios.go

@@ -22,23 +22,20 @@ import (
 
 type tun struct {
 	io.ReadWriteCloser
-	vpnNetworks      []netip.Prefix
+	vpnNetworks []netip.Prefix
-	unsafeNetworks   []netip.Prefix
+	Routes      atomic.Pointer[[]Route]
-	unsafeIPv4Origin netip.Prefix
+	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
-	Routes           atomic.Pointer[[]Route]
+	l           *logrus.Logger
-	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
-	l                *logrus.Logger
 }
 
-func newTun(_ *config.C, _ *logrus.Logger, _ []netip.Prefix, _ []netip.Prefix, _ bool) (*tun, error) {
+func newTun(_ *config.C, _ *logrus.Logger, _ []netip.Prefix, _ bool) (*tun, error) {
 	return nil, fmt.Errorf("newTun not supported in iOS")
 }
 
-func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix) (*tun, error) {
+func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
 	file := os.NewFile(uintptr(deviceFd), "/dev/tun")
 	t := &tun{
 		vpnNetworks:     vpnNetworks,
-		unsafeNetworks:  unsafeNetworks,
 		ReadWriteCloser: &tunReadCloser{f: file},
 		l:               l,
 	}
@@ -72,8 +69,6 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
-	t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
-
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -152,18 +147,6 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
-func (t *tun) UnsafeNetworks() []netip.Prefix {
-	return t.unsafeNetworks
-}
-
-func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return t.unsafeIPv4Origin
-}
-
-func (t *tun) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (t *tun) Name() string {
 	return "iOS"
 }

overlay/tun_linux.go

@@ -26,15 +26,14 @@ import (
 
 type tun struct {
 	io.ReadWriteCloser
-	fd             int
+	fd          int
-	Device         string
+	Device      string
-	vpnNetworks    []netip.Prefix
+	vpnNetworks []netip.Prefix
-	unsafeNetworks []netip.Prefix
+	MaxMTU      int
-	MaxMTU         int
+	DefaultMTU  int
-	DefaultMTU     int
+	TXQueueLen  int
-	TXQueueLen     int
+	deviceIndex int
-	deviceIndex    int
+	ioctlFd     uintptr
-	ioctlFd        uintptr
 
 	Routes                    atomic.Pointer[[]Route]
 	routeTree                 atomic.Pointer[bart.Table[routing.Gateways]]
@@ -47,9 +46,6 @@ type tun struct {
 	routesFromSystem     map[netip.Prefix]routing.Gateways
 	routesFromSystemLock sync.Mutex
 
-	snatAddr         netip.Prefix
-	unsafeIPv4Origin netip.Prefix
-
 	l *logrus.Logger
 }
 
@@ -57,18 +53,6 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
-func (t *tun) UnsafeNetworks() []netip.Prefix {
-	return t.unsafeNetworks
-}
-
-func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return t.unsafeIPv4Origin
-}
-
-func (t *tun) SNATAddress() netip.Prefix {
-	return t.snatAddr
-}
-
 type ifReq struct {
 	Name  [16]byte
 	Flags uint16
@@ -87,10 +71,10 @@ type ifreqQLEN struct {
 	pad   [8]byte
 }
 
-func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix) (*tun, error) {
+func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
 	file := os.NewFile(uintptr(deviceFd), "/dev/net/tun")
 
-	t, err := newTunGeneric(c, l, file, vpnNetworks, unsafeNetworks)
+	t, err := newTunGeneric(c, l, file, vpnNetworks)
 	if err != nil {
 		return nil, err
 	}
@@ -100,7 +84,7 @@ func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []net
 	return t, nil
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, multiqueue bool) (*tun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, multiqueue bool) (*tun, error) {
 	fd, err := unix.Open("/dev/net/tun", os.O_RDWR, 0)
 	if err != nil {
 		// If /dev/net/tun doesn't exist, try to create it (will happen in docker)
@@ -139,7 +123,7 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNet
 	name := strings.Trim(string(req.Name[:]), "\x00")
 
 	file := os.NewFile(uintptr(fd), "/dev/net/tun")
-	t, err := newTunGeneric(c, l, file, vpnNetworks, unsafeNetworks)
+	t, err := newTunGeneric(c, l, file, vpnNetworks)
 	if err != nil {
 		return nil, err
 	}
@@ -149,12 +133,11 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNet
 	return t, nil
 }
 
-func newTunGeneric(c *config.C, l *logrus.Logger, file *os.File, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix) (*tun, error) {
+func newTunGeneric(c *config.C, l *logrus.Logger, file *os.File, vpnNetworks []netip.Prefix) (*tun, error) {
 	t := &tun{
 		ReadWriteCloser:           file,
 		fd:                        int(file.Fd()),
 		vpnNetworks:               vpnNetworks,
-		unsafeNetworks:            unsafeNetworks,
 		TXQueueLen:                c.GetInt("tun.tx_queue", 500),
 		useSystemRoutes:           c.GetBool("tun.use_system_route_table", false),
 		useSystemRoutesBufferSize: c.GetInt("tun.use_system_route_table_buffer_size", 0),
@@ -187,11 +170,6 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
-	if initial {
-		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes) //todo MUST be different from t.snatAddr!
-		t.snatAddr = prepareSnatAddr(t, t.l, c)
-	}
-
 	routeTree, err := makeRouteTree(t.l, routes, true)
 	if err != nil {
 		return err
@@ -335,17 +313,6 @@ func (t *tun) addIPs(link netlink.Link) error {
 		}
 	}
 
-	if t.unsafeIPv4Origin.IsValid() {
-		newAddrs = append(newAddrs, &netlink.Addr{
-			IPNet: &net.IPNet{
-				IP:   t.unsafeIPv4Origin.Addr().AsSlice(),
-				Mask: net.CIDRMask(t.unsafeIPv4Origin.Bits(), t.unsafeIPv4Origin.Addr().BitLen()),
-			},
-			Label: t.unsafeIPv4Origin.Addr().Zone(),
-		})
-		t.l.WithField("address", t.unsafeIPv4Origin).Info("Adding origin address for IPv4 unsafe_routes")
-	}
-
 	//add all new addresses
 	for i := range newAddrs {
 		//AddrReplace still adds new IPs, but if their properties change it will change them as well
@@ -433,13 +400,7 @@ func (t *tun) Activate() error {
 	//set route MTU
 	for i := range t.vpnNetworks {
 		if err = t.setDefaultRoute(t.vpnNetworks[i]); err != nil {
-			return fmt.Errorf("failed to set default route MTU for %s: %w", t.vpnNetworks[i], err)
+			return fmt.Errorf("failed to set default route MTU: %w", err)
-		}
-	}
-
-	if t.unsafeIPv4Origin.IsValid() {
-		if err = t.setDefaultRoute(t.unsafeIPv4Origin); err != nil {
-			return fmt.Errorf("failed to set default route MTU for %s: %w", t.unsafeIPv4Origin, err)
 		}
 	}
 
@@ -466,23 +427,6 @@ func (t *tun) setMTU() {
 	}
 }
 
-func (t *tun) setSnatRoute() error {
-	dr := &net.IPNet{
-		IP:   t.snatAddr.Masked().Addr().AsSlice(),
-		Mask: net.CIDRMask(t.snatAddr.Bits(), t.snatAddr.Addr().BitLen()),
-	}
-
-	nr := netlink.Route{
-		LinkIndex: t.deviceIndex,
-		Dst:       dr,
-		Scope:     unix.RT_SCOPE_LINK,
-		//Protocol: unix.RTPROT_KERNEL,
-		Table: unix.RT_TABLE_MAIN,
-		Type:  unix.RTN_UNICAST,
-	}
-	return netlink.RouteReplace(&nr)
-}
-
 func (t *tun) setDefaultRoute(cidr netip.Prefix) error {
 	dr := &net.IPNet{
 		IP:   cidr.Masked().Addr().AsSlice(),
@@ -559,13 +503,6 @@ func (t *tun) addRoutes(logErrors bool) error {
 		}
 	}
 
-	if t.snatAddr.IsValid() {
-		//at least for Linux, we need to set a return route for the SNATted traffic in order to satisfy the reverse-path filter,
-		//and to help the kernel deliver our reply traffic to the tun device.
-		//however, it is important that we do not actually /assign/ the SNAT address,
-		//since link-local addresses will not be routed between interfaces without significant trickery.
-		return t.setSnatRoute()
-	}
 	return nil
 }
 

overlay/tun_netbsd.go

@@ -58,25 +58,23 @@ type addrLifetime struct {
 }
 
 type tun struct {
-	Device           string
+	Device      string
-	vpnNetworks      []netip.Prefix
+	vpnNetworks []netip.Prefix
-	unsafeNetworks   []netip.Prefix
+	MTU         int
-	unsafeIPv4Origin netip.Prefix
+	Routes      atomic.Pointer[[]Route]
-	MTU              int
+	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
-	Routes           atomic.Pointer[[]Route]
+	l           *logrus.Logger
-	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
+	f           *os.File
-	l                *logrus.Logger
+	fd          int
-	f                *os.File
-	fd               int
 }
 
 var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*tun, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in NetBSD")
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*tun, error) {
+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", "")
@@ -352,10 +350,6 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
-	if initial {
-		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
-	}
-
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -392,18 +386,6 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
-func (t *tun) UnsafeNetworks() []netip.Prefix {
-	return t.unsafeNetworks
-}
-
-func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return t.unsafeIPv4Origin
-}
-
-func (t *tun) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (t *tun) Name() string {
 	return t.Device
 }

overlay/tun_openbsd.go

@@ -49,27 +49,25 @@ type ifreq struct {
 }
 
 type tun struct {
-	Device           string
+	Device      string
-	vpnNetworks      []netip.Prefix
+	vpnNetworks []netip.Prefix
-	unsafeNetworks   []netip.Prefix
+	MTU         int
-	unsafeIPv4Origin netip.Prefix
+	Routes      atomic.Pointer[[]Route]
-	MTU              int
+	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
-	Routes           atomic.Pointer[[]Route]
+	l           *logrus.Logger
-	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
+	f           *os.File
-	l                *logrus.Logger
+	fd          int
-	f                *os.File
-	fd               int
 	// cache out buffer since we need to prepend 4 bytes for tun metadata
 	out []byte
 }
 
 var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*tun, error) {
+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, unsafeNetworks []netip.Prefix, _ bool) (*tun, error) {
+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", "")
@@ -91,13 +89,12 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNet
 	}
 
 	t := &tun{
-		f:              os.NewFile(uintptr(fd), ""),
+		f:           os.NewFile(uintptr(fd), ""),
-		fd:             fd,
+		fd:          fd,
-		Device:         deviceName,
+		Device:      deviceName,
-		vpnNetworks:    vpnNetworks,
+		vpnNetworks: vpnNetworks,
-		unsafeNetworks: unsafeNetworks,
+		MTU:         c.GetInt("tun.mtu", DefaultMTU),
-		MTU:            c.GetInt("tun.mtu", DefaultMTU),
+		l:           l,
-		l:              l,
 	}
 
 	err = t.reload(c, true)
@@ -273,10 +270,6 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
-	if initial {
-		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
-	}
-
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -313,18 +306,6 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
-func (t *tun) UnsafeNetworks() []netip.Prefix {
-	return t.unsafeNetworks
-}
-
-func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return t.unsafeIPv4Origin
-}
-
-func (t *tun) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (t *tun) Name() string {
 	return t.Device
 }

overlay/tun_snat_test.go

@@ -1,179 +0,0 @@
-package overlay
-
-import (
-	"io"
-	"net/netip"
-	"testing"
-
-	"github.com/sirupsen/logrus"
-	"github.com/slackhq/nebula/config"
-	"github.com/slackhq/nebula/routing"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// mockDevice is a minimal Device implementation for testing prepareUnsafeOriginAddr.
-type mockDevice struct {
-	networks       []netip.Prefix
-	unsafeNetworks []netip.Prefix
-	snatAddr       netip.Prefix
-	unsafeSnatAddr netip.Prefix
-}
-
-func (d *mockDevice) Read([]byte) (int, error)                         { return 0, nil }
-func (d *mockDevice) Write([]byte) (int, error)                        { return 0, nil }
-func (d *mockDevice) Close() error                                     { return nil }
-func (d *mockDevice) Activate() error                                  { return nil }
-func (d *mockDevice) Networks() []netip.Prefix                         { return d.networks }
-func (d *mockDevice) UnsafeNetworks() []netip.Prefix                   { return d.unsafeNetworks }
-func (d *mockDevice) SNATAddress() netip.Prefix                        { return d.snatAddr }
-func (d *mockDevice) UnsafeIPv4OriginAddress() netip.Prefix            { return d.unsafeSnatAddr }
-func (d *mockDevice) Name() string                                     { return "mock" }
-func (d *mockDevice) RoutesFor(netip.Addr) routing.Gateways            { return routing.Gateways{} }
-func (d *mockDevice) SupportsMultiqueue() bool                         { return false }
-func (d *mockDevice) NewMultiQueueReader() (io.ReadWriteCloser, error) { return nil, nil }
-
-func TestPrepareSnatAddr_V4Primary_NoSnat(t *testing.T) {
-	l := logrus.New()
-	l.SetLevel(logrus.PanicLevel)
-	c := config.NewC(l)
-
-	// If the device has an IPv4 primary address, no SNAT needed
-	d := &mockDevice{
-		networks: []netip.Prefix{netip.MustParsePrefix("10.0.0.1/24")},
-	}
-	result := prepareUnsafeOriginAddr(d, l, c, nil)
-	assert.Equal(t, netip.Prefix{}, result, "should not assign SNAT addr when device has IPv4 primary")
-}
-
-func TestPrepareSnatAddr_V6Primary_NoUnsafeOrRoutes(t *testing.T) {
-	l := logrus.New()
-	l.SetLevel(logrus.PanicLevel)
-	c := config.NewC(l)
-
-	// IPv6 primary but no unsafe networks or IPv4 routes
-	d := &mockDevice{
-		networks: []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
-	}
-	result := prepareUnsafeOriginAddr(d, l, c, nil)
-	assert.Equal(t, netip.Prefix{}, result, "should not assign SNAT addr without IPv4 unsafe networks or routes")
-}
-
-func TestPrepareSnatAddr_V6Primary_WithV4Unsafe(t *testing.T) {
-	l := logrus.New()
-	l.SetLevel(logrus.PanicLevel)
-	c := config.NewC(l)
-
-	// IPv6 primary with IPv4 unsafe network -> should get SNAT addr
-	d := &mockDevice{
-		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
-		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("192.168.0.0/16")},
-	}
-	result := prepareSnatAddr(d, l, c)
-	require.True(t, result.IsValid(), "should assign SNAT addr")
-	assert.True(t, result.Addr().Is4(), "SNAT addr should be IPv4")
-	assert.True(t, result.Addr().IsLinkLocalUnicast(), "SNAT addr should be link-local")
-	assert.Equal(t, 32, result.Bits(), "SNAT addr should be /32")
-
-	result = prepareUnsafeOriginAddr(d, l, c, nil)
-	require.False(t, result.IsValid(), "no routes = no origin addr needed")
-}
-
-func TestPrepareUnsafeOriginAddr_V6Primary_WithV4Route(t *testing.T) {
-	l := logrus.New()
-	l.SetLevel(logrus.PanicLevel)
-	c := config.NewC(l)
-
-	// IPv6 primary with IPv4 route -> should get SNAT addr
-	d := &mockDevice{
-		networks: []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
-	}
-	routes := []Route{
-		{Cidr: netip.MustParsePrefix("10.0.0.0/8")},
-	}
-	result := prepareUnsafeOriginAddr(d, l, c, routes)
-	require.True(t, result.IsValid(), "should assign SNAT addr when IPv4 route exists")
-	assert.True(t, result.Addr().Is4())
-	assert.True(t, result.Addr().IsLinkLocalUnicast())
-
-	result = prepareSnatAddr(d, l, c)
-	require.False(t, result.IsValid(), "no UnsafeNetworks = no snat addr needed")
-}
-
-func TestPrepareSnatAddr_V6Primary_V6UnsafeOnly(t *testing.T) {
-	l := logrus.New()
-	l.SetLevel(logrus.PanicLevel)
-	c := config.NewC(l)
-
-	// IPv6 primary with only IPv6 unsafe network -> no SNAT needed
-	d := &mockDevice{
-		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
-		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("fd01::/64")},
-	}
-	result := prepareUnsafeOriginAddr(d, l, c, nil)
-	assert.Equal(t, netip.Prefix{}, result, "should not assign SNAT addr for IPv6-only unsafe networks")
-}
-
-func TestPrepareSnatAddr_ManualAddress(t *testing.T) {
-	l := logrus.New()
-	l.SetLevel(logrus.PanicLevel)
-	c := config.NewC(l)
-	c.Settings["tun"] = map[string]any{
-		"snat_address_for_4over6": "169.254.42.42",
-	}
-
-	d := &mockDevice{
-		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
-		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("192.168.0.0/16")},
-	}
-	result := prepareSnatAddr(d, l, c)
-	require.True(t, result.IsValid())
-	assert.Equal(t, netip.MustParseAddr("169.254.42.42"), result.Addr())
-	assert.Equal(t, 32, result.Bits())
-}
-
-func TestPrepareSnatAddr_InvalidManualAddress_Fallback(t *testing.T) {
-	l := logrus.New()
-	l.SetLevel(logrus.PanicLevel)
-	c := config.NewC(l)
-	c.Settings["tun"] = map[string]any{
-		"snat_address_for_4over6": "not-an-ip",
-	}
-
-	d := &mockDevice{
-		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
-		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("192.168.0.0/16")},
-	}
-	result := prepareSnatAddr(d, l, c)
-	// Should fall back to auto-assignment
-	require.True(t, result.IsValid(), "should fall back to auto-assigned address")
-	assert.True(t, result.Addr().Is4())
-	assert.True(t, result.Addr().IsLinkLocalUnicast())
-}
-
-func TestPrepareSnatAddr_AutoGenerated_Range(t *testing.T) {
-	l := logrus.New()
-	l.SetLevel(logrus.PanicLevel)
-	c := config.NewC(l)
-
-	d := &mockDevice{
-		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
-		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("192.168.0.0/16")},
-	}
-
-	// Generate several addresses and verify they're all in the expected range
-	for i := 0; i < 100; i++ {
-		result := prepareSnatAddr(d, l, c)
-		require.True(t, result.IsValid())
-		addr := result.Addr()
-		octets := addr.As4()
-		assert.Equal(t, byte(169), octets[0], "first octet should be 169")
-		assert.Equal(t, byte(254), octets[1], "second octet should be 254")
-		// Should not have .0 in the last octet
-		assert.NotEqual(t, byte(0), octets[3], "last octet should not be 0")
-		// Should not be 169.254.255.255 (broadcast)
-		if octets[2] == 255 {
-			assert.NotEqual(t, byte(255), octets[3], "should not be broadcast address")
-		}
-	}
-}

overlay/tun_test.go

@@ -1,37 +0,0 @@
-package overlay
-
-import (
-	"bytes"
-	"net/netip"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func TestLinkLocal(t *testing.T) {
-	r := bytes.NewReader([]byte{42, 99})
-	result := genLinkLocal(r)
-	assert.Equal(t, netip.MustParsePrefix("169.254.42.99/32"), result, "genLinkLocal with a deterministic randomizer")
-
-	result = genLinkLocal(nil)
-	assert.True(t, result.IsValid(), "genLinkLocal with nil randomizer should be valid")
-	assert.True(t, result.Addr().IsLinkLocalUnicast(), "genLinkLocal with nil randomizer should be link-local")
-
-	result = coerceLinkLocal([]byte{169, 254, 100, 50})
-	assert.Equal(t, netip.MustParsePrefix("169.254.100.50/32"), result, "coerceLinkLocal should pass through normal values")
-
-	result = coerceLinkLocal([]byte{169, 254, 0, 0})
-	assert.Equal(t, netip.MustParsePrefix("169.254.0.1/32"), result, "coerceLinkLocal should bump .0 last octet to .1")
-
-	result = coerceLinkLocal([]byte{169, 254, 255, 255})
-	assert.Equal(t, netip.MustParsePrefix("169.254.255.254/32"), result, "coerceLinkLocal should bump broadcast 255.255 to 255.254")
-
-	result = coerceLinkLocal([]byte{169, 254, 0, 1})
-	assert.Equal(t, netip.MustParsePrefix("169.254.0.1/32"), result, "coerceLinkLocal should leave .1 last octet unchanged")
-
-	result = coerceLinkLocal([]byte{169, 254, 255, 254})
-	assert.Equal(t, netip.MustParsePrefix("169.254.255.254/32"), result, "coerceLinkLocal should leave 255.254 unchanged")
-
-	result = coerceLinkLocal([]byte{169, 254, 255, 100})
-	assert.Equal(t, netip.MustParsePrefix("169.254.255.100/32"), result, "coerceLinkLocal should leave 255.100 unchanged")
-}

overlay/tun_tester.go

@@ -17,21 +17,18 @@ import (
 )
 
 type TestTun struct {
-	Device           string
+	Device      string
-	vpnNetworks      []netip.Prefix
+	vpnNetworks []netip.Prefix
-	unsafeNetworks   []netip.Prefix
+	Routes      []Route
-	snatAddr         netip.Prefix
+	routeTree   *bart.Table[routing.Gateways]
-	unsafeIPv4Origin netip.Prefix
+	l           *logrus.Logger
-	Routes           []Route
-	routeTree        *bart.Table[routing.Gateways]
-	l                *logrus.Logger
 
 	closed    atomic.Bool
 	rxPackets chan []byte // Packets to receive into nebula
 	TxPackets chan []byte // Packets transmitted outside by nebula
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*TestTun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*TestTun, error) {
 	_, routes, err := getAllRoutesFromConfig(c, vpnNetworks, true)
 	if err != nil {
 		return nil, err
@@ -41,22 +38,18 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNet
 		return nil, err
 	}
 
-	tt := &TestTun{
+	return &TestTun{
-		Device:         c.GetString("tun.dev", ""),
+		Device:      c.GetString("tun.dev", ""),
-		vpnNetworks:    vpnNetworks,
+		vpnNetworks: vpnNetworks,
-		unsafeNetworks: unsafeNetworks,
+		Routes:      routes,
-		Routes:         routes,
+		routeTree:   routeTree,
-		routeTree:      routeTree,
+		l:           l,
-		l:              l,
+		rxPackets:   make(chan []byte, 10),
-		rxPackets:      make(chan []byte, 10),
+		TxPackets:   make(chan []byte, 10),
-		TxPackets:      make(chan []byte, 10),
+	}, nil
-	}
-	tt.unsafeIPv4Origin = prepareUnsafeOriginAddr(tt, l, c, routes)
-	tt.snatAddr = prepareSnatAddr(tt, tt.l, c)
-	return tt, nil
 }
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*TestTun, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*TestTun, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported")
 }
 
@@ -146,15 +139,3 @@ func (t *TestTun) SupportsMultiqueue() bool {
 func (t *TestTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented")
 }
-
-func (t *TestTun) UnsafeNetworks() []netip.Prefix {
-	return t.unsafeNetworks
-}
-
-func (t *TestTun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return t.unsafeIPv4Origin
-}
-
-func (t *TestTun) SNATAddress() netip.Prefix {
-	return t.snatAddr
-}

overlay/tun_windows.go

@@ -28,23 +28,21 @@ import (
 const tunGUIDLabel = "Fixed Nebula Windows GUID v1"
 
 type winTun struct {
-	Device           string
+	Device      string
-	vpnNetworks      []netip.Prefix
+	vpnNetworks []netip.Prefix
-	unsafeNetworks   []netip.Prefix
+	MTU         int
-	unsafeIPv4Origin netip.Prefix
+	Routes      atomic.Pointer[[]Route]
-	MTU              int
+	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
-	Routes           atomic.Pointer[[]Route]
+	l           *logrus.Logger
-	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
-	l                *logrus.Logger
 
 	tun *wintun.NativeTun
 }
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (Device, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (Device, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in Windows")
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*winTun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*winTun, error) {
 	err := checkWinTunExists()
 	if err != nil {
 		return nil, fmt.Errorf("can not load the wintun driver: %w", err)
@@ -57,11 +55,10 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNet
 	}
 
 	t := &winTun{
-		Device:         deviceName,
+		Device:      deviceName,
-		vpnNetworks:    vpnNetworks,
+		vpnNetworks: vpnNetworks,
-		unsafeNetworks: unsafeNetworks,
+		MTU:         c.GetInt("tun.mtu", DefaultMTU),
-		MTU:            c.GetInt("tun.mtu", DefaultMTU),
+		l:           l,
-		l:              l,
 	}
 
 	err = t.reload(c, true)
@@ -105,10 +102,6 @@ func (t *winTun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
-	if initial {
-		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
-	}
-
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -139,12 +132,7 @@ func (t *winTun) reload(c *config.C, initial bool) error {
 func (t *winTun) Activate() error {
 	luid := winipcfg.LUID(t.tun.LUID())
 
-	prefixes := t.vpnNetworks
+	err := luid.SetIPAddresses(t.vpnNetworks)
-	if t.unsafeIPv4Origin.IsValid() {
-		prefixes = append(prefixes, t.unsafeIPv4Origin)
-	}
-
-	err := luid.SetIPAddresses(prefixes)
 	if err != nil {
 		return fmt.Errorf("failed to set address: %w", err)
 	}
@@ -237,18 +225,6 @@ func (t *winTun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
-func (t *winTun) UnsafeNetworks() []netip.Prefix {
-	return t.unsafeNetworks
-}
-
-func (t *winTun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return t.unsafeIPv4Origin
-}
-
-func (t *winTun) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (t *winTun) Name() string {
 	return t.Device
 }

overlay/user.go

@@ -9,7 +9,7 @@ import (
 	"github.com/slackhq/nebula/routing"
 )
 
-func NewUserDeviceFromConfig(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, routines int) (Device, error) {
+func NewUserDeviceFromConfig(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error) {
 	return NewUserDevice(vpnNetworks)
 }
 
@@ -36,17 +36,6 @@ type UserDevice struct {
 	inboundWriter *io.PipeWriter
 }
 
-func (d *UserDevice) UnsafeNetworks() []netip.Prefix {
-	return nil
-}
-
-func (d *UserDevice) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-func (d *UserDevice) UnsafeIPv4OriginAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (d *UserDevice) Activate() error {
 	return nil
 }

pki.go

@@ -91,7 +91,7 @@ func (p *PKI) reload(c *config.C, initial bool) error {
 }
 
 func (p *PKI) reloadCerts(c *config.C, initial bool) *util.ContextualError {
-	newState, err := newCertStateFromConfig(c, p.l)
+	newState, err := newCertStateFromConfig(c)
 	if err != nil {
 		return util.NewContextualError("Could not load client cert", nil, err)
 	}
@@ -102,7 +102,7 @@ func (p *PKI) reloadCerts(c *config.C, initial bool) *util.ContextualError {
 			if currentState.v1Cert == nil {
 				//adding certs is fine, actually. Networks-in-common confirmed in newCertState().
 			} else {
-				// did IP in cert change? if so, don't set. If we ever allow this, need to set p.firewallReloadNeeded
+				// did IP in cert change? if so, don't set
 				if !slices.Equal(currentState.v1Cert.Networks(), newState.v1Cert.Networks()) {
 					return util.NewContextualError(
 						"Networks in new cert was different from old",
@@ -158,14 +158,6 @@ func (p *PKI) reloadCerts(c *config.C, initial bool) *util.ContextualError {
 			}
 		}
 
-		newUN := newState.GetDefaultCertificate().UnsafeNetworks()
-		oldUN := currentState.GetDefaultCertificate().UnsafeNetworks()
-		if !slices.Equal(newUN, oldUN) {
-			//todo I don't love this, because other clients will see the new assignments and act on them, but we will not be able to.
-			//I think we need to wire this into the firewall reload.
-			p.l.WithFields(m{"previous": oldUN, "new": newUN}).Warning("UnsafeNetworks assignments differ. A restart is required in order for this to take effect.")
-		}
-
 		// Cipher cant be hot swapped so just leave it at what it was before
 		newState.cipher = currentState.cipher
 
@@ -268,7 +260,7 @@ func (cs *CertState) MarshalJSON() ([]byte, error) {
 	return json.Marshal(msg)
 }
 
-func newCertStateFromConfig(c *config.C, l *logrus.Logger) (*CertState, error) {
+func newCertStateFromConfig(c *config.C) (*CertState, error) {
 	var err error
 
 	privPathOrPEM := c.GetString("pki.key", "")
@@ -352,33 +344,10 @@ func newCertStateFromConfig(c *config.C, l *logrus.Logger) (*CertState, error) {
 		return nil, fmt.Errorf("unknown pki.initiating_version: %v", rawInitiatingVersion)
 	}
 
-	return newCertState(l, initiatingVersion, v1, v2, isPkcs11, curve, rawKey)
+	return newCertState(initiatingVersion, v1, v2, isPkcs11, curve, rawKey)
 }
 
-func compareUnsafeNetworksAcrossCertVersions(v1, v2 cert.Certificate) error {
+func newCertState(dv cert.Version, v1, v2 cert.Certificate, pkcs11backed bool, privateKeyCurve cert.Curve, privateKey []byte) (*CertState, error) {
-	if v1 == nil || v2 == nil {
-		return nil //can't be a problem if we don't have one of the kinds of cert
-	}
-
-	v4UnsafeNets := 0
-	for _, n := range v2.UnsafeNetworks() {
-		if n.Addr().Is6() {
-			continue // V1 certs can't have IPv6 unsafe networks
-		} else {
-			v4UnsafeNets++
-		}
-		if !slices.Contains(v1.UnsafeNetworks(), n) {
-			return errors.New("UnsafeNetworks mismatch")
-		}
-	}
-	if len(v1.UnsafeNetworks()) != v4UnsafeNets {
-		return errors.New("UnsafeNetworks mismatch")
-	}
-
-	return nil
-}
-
-func newCertState(l *logrus.Logger, dv cert.Version, v1, v2 cert.Certificate, pkcs11backed bool, privateKeyCurve cert.Curve, privateKey []byte) (*CertState, error) {
 	cs := CertState{
 		privateKey:               privateKey,
 		pkcs11Backed:             pkcs11backed,
@@ -401,12 +370,6 @@ func newCertState(l *logrus.Logger, dv cert.Version, v1, v2 cert.Certificate, pk
 		}
 
 		cs.initiatingVersion = dv
-
-		warn := compareUnsafeNetworksAcrossCertVersions(v1, v2)
-		if warn != nil {
-			l.WithFields(m{"UnsafeNetworksV1": v1.UnsafeNetworks(), "UnsafeNetworksV2": v2.UnsafeNetworks()}).
-				Warning("the IPv4 UnsafeNetworks assigned in the V1 certificate do not match the ones in V2")
-		}
 	}
 
 	if v1 != nil {

snat.go

@@ -1,91 +0,0 @@
-package nebula
-
-import (
-	"encoding/binary"
-	"net/netip"
-)
-
-func recalcIPv4Checksum(data []byte, oldSrcIP netip.Addr, newSrcIP netip.Addr) {
-	oldChecksum := binary.BigEndian.Uint16(data[10:12])
-	//because of how checksums work, we can re-use this function
-	checksum := calcNewTransportChecksum(oldChecksum, oldSrcIP, 0, newSrcIP, 0)
-	binary.BigEndian.PutUint16(data[10:12], checksum)
-}
-
-func calcNewTransportChecksum(oldChecksum uint16, oldSrcIP netip.Addr, oldSrcPort uint16, newSrcIP netip.Addr, newSrcPort uint16) uint16 {
-	oldIP := binary.BigEndian.Uint32(oldSrcIP.AsSlice())
-	newIP := binary.BigEndian.Uint32(newSrcIP.AsSlice())
-
-	// Start with inverted checksum
-	checksum := uint32(^oldChecksum)
-
-	// Subtract old IP (as two 16-bit words)
-	checksum += uint32(^uint16(oldIP >> 16))
-	checksum += uint32(^uint16(oldIP & 0xFFFF))
-
-	// Subtract old port
-	checksum += uint32(^oldSrcPort)
-
-	// Add new IP (as two 16-bit words)
-	checksum += uint32(newIP >> 16)
-	checksum += uint32(newIP & 0xFFFF)
-
-	// Add new port
-	checksum += uint32(newSrcPort)
-
-	// Fold carries
-	for checksum > 0xFFFF {
-		checksum = (checksum & 0xFFFF) + (checksum >> 16)
-	}
-
-	// Return ones' complement
-	return ^uint16(checksum)
-}
-
-func recalcV4TransportChecksum(offsetInsideHeader int, data []byte, oldSrcIP netip.AddrPort, newSrcIP netip.AddrPort) {
-	ipHeaderOffset := int(data[0]&0x0F) * 4
-	offset := ipHeaderOffset + offsetInsideHeader
-	oldcsum := binary.BigEndian.Uint16(data[offset : offset+2])
-	checksum := calcNewTransportChecksum(oldcsum, oldSrcIP.Addr(), oldSrcIP.Port(), newSrcIP.Addr(), newSrcIP.Port())
-	binary.BigEndian.PutUint16(data[offset:offset+2], checksum)
-}
-
-func recalcUDPv4Checksum(data []byte, oldSrcIP netip.AddrPort, newSrcIP netip.AddrPort) {
-	const offsetInsideHeader = 6
-	recalcV4TransportChecksum(offsetInsideHeader, data, oldSrcIP, newSrcIP)
-}
-
-func recalcTCPv4Checksum(data []byte, oldSrcIP netip.AddrPort, newSrcIP netip.AddrPort) {
-	const offsetInsideHeader = 16
-	recalcV4TransportChecksum(offsetInsideHeader, data, oldSrcIP, newSrcIP)
-}
-
-func calcNewICMPChecksum(oldChecksum uint16, oldCode uint16, newCode uint16, oldID uint16, newID uint16) uint16 {
-	// Start with inverted checksum
-	checksum := uint32(^oldChecksum)
-
-	// Subtract old stuff
-	checksum += uint32(^oldCode)
-	checksum += uint32(^oldID)
-
-	// Add new stuff
-	checksum += uint32(newCode)
-	checksum += uint32(newID)
-
-	// Fold carries
-	for checksum > 0xFFFF {
-		checksum = (checksum & 0xFFFF) + (checksum >> 16)
-	}
-
-	// Return ones' complement
-	return ^uint16(checksum)
-}
-
-func recalcICMPv4Checksum(data []byte, oldCode uint16, newCode uint16, oldID uint16, newID uint16) {
-	const offsetInsideHeader = 2
-	ipHeaderOffset := int(data[0]&0x0F) * 4
-	offset := ipHeaderOffset + offsetInsideHeader
-	oldChecksum := binary.BigEndian.Uint16(data[offset : offset+2])
-	checksum := calcNewICMPChecksum(oldChecksum, oldCode, newCode, oldID, newID)
-	binary.BigEndian.PutUint16(data[offset:offset+2], checksum)
-}

ssh.go

@@ -632,6 +632,9 @@ func sshCreateTunnel(ifce *Interface, fs any, a []string, w sshd.StringWriter) e
 	}
 
 	hostInfo = ifce.handshakeManager.StartHandshake(vpnAddr, nil)
+	if hostInfo == nil {
+		return w.WriteLine("Handshake rate limit reached")
+	}
 	if addr.IsValid() {
 		hostInfo.SetRemote(addr)
 	}

test/tun.go

@@ -10,18 +10,6 @@ import (
 
 type NoopTun struct{}
 
-func (NoopTun) UnsafeNetworks() []netip.Prefix {
-	return nil
-}
-
-func (NoopTun) SNATAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
-func (NoopTun) UnsafeIPv4OriginAddress() netip.Prefix {
-	return netip.Prefix{}
-}
-
 func (NoopTun) RoutesFor(addr netip.Addr) routing.Gateways {
 	return routing.Gateways{}
 }