[client] Bump go-netroute to v0.4.0 and drop fork (#6062)

client/internal/portforward/pcp/nat.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
+	"runtime"
 	"sync"
 	"time"
 
@@ -177,7 +178,12 @@ func getDefaultGateway() (gateway net.IP, localIP net.IP, err error) {
 		return nil, nil, err
 	}
 
-	_, gateway, localIP, err = router.Route(net.IPv4zero)
+	dst := net.IPv4zero
+	if runtime.GOOS == "linux" {
+		// go-netroute v0.4.0 rejects unspecified destinations client-side on Linux.
+		dst = net.IPv4(0, 0, 0, 1)
+	}
+	_, gateway, localIP, err = router.Route(dst)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -196,7 +202,12 @@ func getDefaultGateway6() (gateway net.IP, localIP net.IP, err error) {
 		return nil, nil, err
 	}
 
-	_, gateway, localIP, err = router.Route(net.IPv6zero)
+	dst := net.IPv6zero
+	if runtime.GOOS == "linux" {
+		// ::2
+		dst = net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2}
+	}
+	_, gateway, localIP, err = router.Route(dst)
 	if err != nil {
 		return nil, nil, err
 	}

client/internal/routemanager/systemops/systemops_generic.go

@@ -342,6 +342,22 @@ func GetNextHop(ip netip.Addr) (Nexthop, error) {
 	if err != nil {
 		return Nexthop{}, fmt.Errorf("new netroute: %w", err)
 	}
+
+	// go-netroute v0.4.0 rejects unspecified destinations on Linux with a hard
+	// client-side check. Substitute the lowest non-loopback address so the
+	// lookup falls through to the default route (::1 / 127.0.0.1 would match
+	// loopback, ::/0.0.0.0 are unspec). BSD/Windows pass the query straight to
+	// the kernel and need no substitution.
+	if runtime.GOOS == "linux" && ip.IsUnspecified() {
+		if ip.Is6() {
+			// ::2
+			ip = netip.AddrFrom16([16]byte{15: 2})
+		} else {
+			// 0.0.0.1
+			ip = netip.AddrFrom4([4]byte{0, 0, 0, 1})
+		}
+	}
+
 	intf, gateway, preferredSrc, err := r.Route(ip.AsSlice())
 	if err != nil {
 		log.Debugf("Failed to get route for %s: %v", ip, err)

client/internal/routemanager/systemops/systemops_generic_test.go

@@ -354,9 +354,13 @@ func TestAddRouteToNonVPNIntf(t *testing.T) {
 			require.NoError(t, err, "Should be able to get IPv4 default route")
 			t.Logf("Initial IPv4 next hop: %s", initialNextHopV4)
 
+			if testCase.prefix.Addr().Is6() && !testCase.expectError {
+				ensureIPv6DefaultRoute(t)
+			}
+
 			initialNextHopV6, err := GetNextHop(netip.IPv6Unspecified())
 			if testCase.prefix.Addr().Is6() &&
-				(errors.Is(err, vars.ErrRouteNotFound) || initialNextHopV6.Intf != nil && strings.HasPrefix(initialNextHopV6.Intf.Name, "utun")) {
+				initialNextHopV6.Intf != nil && strings.HasPrefix(initialNextHopV6.Intf.Name, "utun") {
 				t.Skip("Skipping test as no ipv6 default route is available")
 			}
 			if err != nil && !errors.Is(err, vars.ErrRouteNotFound) {

client/internal/routemanager/systemops/v6route_bsd_test.go

@@ -0,0 +1,30 @@
+//go:build darwin || dragonfly || freebsd || netbsd || openbsd
+
+package systemops
+
+import (
+	"bytes"
+	"os/exec"
+	"testing"
+)
+
+// ensureIPv6DefaultRoute installs an IPv6 default route via the loopback
+// interface so route lookups for global IPv6 prefixes resolve in environments
+// without v6 connectivity. If a default already exists it is left alone.
+func ensureIPv6DefaultRoute(t *testing.T) {
+	t.Helper()
+
+	out, err := exec.Command("route", "-6", "add", "default", "-iface", "lo0").CombinedOutput()
+	if err != nil {
+		// Existing default; nothing to install or clean up.
+		if bytes.Contains(out, []byte("route already in table")) {
+			return
+		}
+		t.Skipf("install IPv6 fallback default route: %v: %s", err, out)
+	}
+	t.Cleanup(func() {
+		if out, err := exec.Command("route", "-6", "delete", "default").CombinedOutput(); err != nil {
+			t.Logf("delete IPv6 fallback default route: %v: %s", err, out)
+		}
+	})
+}

client/internal/routemanager/systemops/v6route_linux_test.go

@@ -0,0 +1,41 @@
+//go:build linux && !android
+
+package systemops
+
+import (
+	"errors"
+	"net"
+	"syscall"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/vishvananda/netlink"
+)
+
+// ensureIPv6DefaultRoute installs a low-preference IPv6 default route via the
+// loopback interface so route lookups for global IPv6 prefixes resolve in
+// environments without v6 connectivity. Any pre-existing default route wins
+// because of its lower metric.
+func ensureIPv6DefaultRoute(t *testing.T) {
+	t.Helper()
+
+	lo, err := netlink.LinkByName("lo")
+	require.NoError(t, err, "find loopback interface")
+
+	route := &netlink.Route{
+		Dst:       &net.IPNet{IP: net.IPv6zero, Mask: net.CIDRMask(0, 128)},
+		LinkIndex: lo.Attrs().Index,
+		Priority:  1 << 20,
+	}
+	if err := netlink.RouteAdd(route); err != nil {
+		if errors.Is(err, syscall.EEXIST) {
+			return
+		}
+		t.Skipf("install IPv6 fallback default route: %v", err)
+	}
+	t.Cleanup(func() {
+		if err := netlink.RouteDel(route); err != nil && !errors.Is(err, syscall.ESRCH) {
+			t.Logf("delete IPv6 fallback default route: %v", err)
+		}
+	})
+}

client/internal/routemanager/systemops/v6route_windows_test.go

@@ -0,0 +1,34 @@
+//go:build windows
+
+package systemops
+
+import (
+	"bytes"
+	"os/exec"
+	"testing"
+)
+
+const loopbackIfaceWindows = "Loopback Pseudo-Interface 1"
+
+// ensureIPv6DefaultRoute installs an IPv6 default route via the loopback
+// interface so route lookups for global IPv6 prefixes resolve in environments
+// without v6 connectivity. If a default already exists it is left alone.
+func ensureIPv6DefaultRoute(t *testing.T) {
+	t.Helper()
+
+	script := `New-NetRoute -DestinationPrefix "::/0" -InterfaceAlias "` + loopbackIfaceWindows + `" -RouteMetric 9999 -PolicyStore ActiveStore -ErrorAction Stop`
+	out, err := exec.Command("powershell", "-Command", script).CombinedOutput()
+	if err != nil {
+		// Existing default; nothing to install or clean up.
+		if bytes.Contains(out, []byte("already exists")) {
+			return
+		}
+		t.Skipf("install IPv6 fallback default route: %v: %s", err, out)
+	}
+	t.Cleanup(func() {
+		script := `Remove-NetRoute -DestinationPrefix "::/0" -InterfaceAlias "` + loopbackIfaceWindows + `" -Confirm:$false -ErrorAction Stop`
+		if out, err := exec.Command("powershell", "-Command", script).CombinedOutput(); err != nil {
+			t.Logf("delete IPv6 fallback default route: %v: %s", err, out)
+		}
+	})
+}